<?xml version="1.0" encoding="utf-8"?>
<posts>
  <row Id="1" PostTypeId="1" AcceptedAnswerId="366" CreationDate="2014-04-15T18:11:01.930" Score="24" ViewCount="1016" Body="&lt;p&gt;The atmosphere is a highly dynamical system, and exhibits many chaotical features.  An operational weather forecasting model tries to model an initial value problem, in fact one of the most famous examples of a chaotic system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Climate&lt;/em&gt; however, is the statistics of the behaviour of the atmosphere over a long period of time.  It is not an initial value problem; it is a boundary value problem.  Whereas small changes in initial values can imply large changes in behaviour over time, can there be any similar behaviour in climate?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, we force a climate model with prescribed atmospheric constituents, coastlines, orbital characteristics, etc.  Can a &lt;em&gt;small&lt;/em&gt; change in any of those boundary values lead to a climate exbiting a different state?  Or, similarly, can, in the context of natural variability only, the climate suddenly switch to a very different state?&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2014-04-20T15:07:33.163" Title="Is climate chaotic?" Tags="|climate|atmosphere|chaos|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2" PostTypeId="1" AcceptedAnswerId="2962" CreationDate="2014-04-15T18:21:53.510" Score="14" ViewCount="166" Body="&lt;p&gt;In-situ measurements in deep convective systems, tropical cyclones, etc., are difficult to perform.  Few if any people would like to fly a small aircraft close to its core, and radiosondes or larger balloons would be ripped to pieces.  Even flying high above the top of such a system may not be a pleasant idea.  However, with unmanned aerial vehicles (UAVs or drones), perhaps higher risks can be taken than with manned aircraft.  And whereas radiosondes cannot be launched, dropsondes should not be a problem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any projects, either operationally or for research purposes, that involve dropping sondes from UAVs flying above deep convective systems, in order to measure profiles of pressure, temperature, as well as cloud and precipitation properties?&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="64" LastEditDate="2014-12-05T19:02:37.117" LastActivityDate="2014-12-05T19:02:37.117" Title="Have there been any attempts to measure profiles through deep convective systems using dropsondes?" Tags="|meteorology|atmosphere|measurements|storms|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="3" PostTypeId="1" AcceptedAnswerId="140" CreationDate="2014-04-15T18:25:40.903" Score="10" ViewCount="122" Body="&lt;p&gt;Remote sounding of the atmosphere is a well-established method used extensively used extensively for operational weather forecasting and scientific research.  Active or passive instruments carried on satellites (or aircraft) can measure profiles of temperature, pressure, trace gases, and particulate matter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is anything similar possible for a ship sailing on the ocean?  What methods exist, in theory and in practice, to remotely sense a profile of temperature, density, salinity, etc., from the ocean floor to the ship?  Or can such profiles only be obtained in-situ?&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2014-04-16T22:27:56.657" Title="What methods exist for remote profiling of oceanic columns?" Tags="|measurements|ocean|remote-sensing|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4" PostTypeId="1" CreationDate="2014-04-15T18:56:43.193" Score="9" ViewCount="165" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Virtual_temperature&quot;&gt;virtual temperature&lt;/a&gt; is a pseudo-temperature taking into account water vapour in the atmosphere in such a way, that the resulting quantity can be used with the ideal gas law and the molar mass for dry air.  Although the most significant in the troposphere, water vapour is not the only trace gas for which the concentration varies through the atmosphere.  Are there any similarly defined pseudo-temperatures, taking into account varying volume mixing ratios for other trace gases?&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="124" LastEditDate="2014-04-30T16:00:11.327" LastActivityDate="2014-04-30T16:00:11.327" Title="Are there any quantities defined analogically to the virtual temperature, but for other gases?" Tags="|atmosphere|meteorology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5" PostTypeId="1" CreationDate="2014-04-15T19:10:00.560" Score="9" ViewCount="173" Body="&lt;p&gt;So we know that surface air temperatures are warmer during El Niño events (which implies that there is more heat in the atmosphere, although maybe it's possible that it also means there's less heat in the oceans?).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm wondering... though.. Could this simply mean that the land surface emits more longwave radiation out into space during periods of El Niño. &lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="111" LastEditDate="2014-12-21T21:52:04.513" LastActivityDate="2014-12-21T21:53:28.560" Title="Does El Niño increase the amount of heat that escapes into space, or does it increase the amount of heat trapped on Earth?" Tags="|atmosphere|enso|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6" PostTypeId="1" CreationDate="2014-04-15T19:15:52.640" Score="13" ViewCount="10098" Body="&lt;p&gt;Do cirrus clouds in the upper troposphere move faster than cumulus and stratus clouds in the lower atmosphere?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What about clouds associated with extratropical systems, compared with clouds in the tropics?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="10681" LastEditDate="2017-09-20T20:01:20.770" LastActivityDate="2017-09-25T14:47:19.227" Title="What determines how fast clouds move?" Tags="|meteorology|atmosphere|clouds|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7" PostTypeId="1" CreationDate="2014-04-15T19:21:12.483" Score="20" ViewCount="1639" Body="&lt;p&gt;So &lt;a href=&quot;http://dspace.mit.edu/openaccess-disseminate/1721.1/52333&quot;&gt;Enderton and Marshall&lt;/a&gt; (2009) wrote an interesting paper on the ocean circulation of various aquaplanets covered with certain terrain: e.g. an aquaplanet with a small ridge of land that ranged from North Pole to South Pole, and studied the effects it had on the ocean circulation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm curious: Has anyone ever applied this type of analysis to a Pangaea-like planet?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorDisplayName="user12525" LastEditDate="2019-04-21T10:36:51.467" LastActivityDate="2019-04-21T10:36:51.467" Title="What was the ocean circulation like during the time of Pangaea?" Tags="|oceanography|paleoclimatology|paleogeography|thermohaline-circulation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8" PostTypeId="1" AcceptedAnswerId="1070" CreationDate="2014-04-15T19:25:48.243" Score="19" ViewCount="750" Body="&lt;p&gt;Figure 1.12 from the &lt;a href=&quot;http://ipcc.ch/report/ar5/wg1/&quot; rel=&quot;noreferrer&quot;&gt;IPCC AR5 WG1 report&lt;/a&gt; (reproduced below) illustrates the different instruments that have been used for weather forecasting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of the methods have been in continuous use since their inception, except one: kites were used, but later disbanded.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is this so?  &lt;a href=&quot;http://www.ctie.monash.edu.au/hargrave/kites_and_meterology.html&quot; rel=&quot;noreferrer&quot;&gt;This Monash university article from 1999&lt;/a&gt; makes the point that they are superseded by radiosondes and aircraft.  However, atmospheric measurements on aircraft are very expensive and mainly used for research as opposed to operational weather forecasting; and, unlike weather kites, they do not (normally) fly in the boundary layer¹.  Radiosondes are only launched once or twice per 24 hours per location.  Passive (operational) space-borne measurements have a lower vertical resolution, in particular near the boundary layer.  I imagine that kites should provide a low-cost, high-resolution (both temporally and vertically) profile of the boundary layer.  Why is it they are not really used operationally anymore?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/VQ0TX.jpg&quot; alt=&quot;IPCC AR5 WG1 Figure 1.12&quot;&gt;&#xA;&lt;sup&gt;&#xA;&lt;br /&gt;Figure 1.12 | Development of capabilities of observations. Top: Changes in the mix and increasing diversity of observations over time create challenges for a consistent climate record (adapted from Brönnimann et al., 2008). Bottom left: First year of temperature data in Global Historical Climatology Network (GHCN) daily database (available at &lt;a href=&quot;http://www.ncdc.noaa.gov/oa/climate/ghcn-daily/&quot; rel=&quot;noreferrer&quot;&gt;http://www.ncdc.noaa.gov/oa/climate/ghcn-daily/&lt;/a&gt;; Menne et al., 2012). Bottom right: Number of satellite instruments from which data have been assimilated in the European Centre for Medium-Range Weather Forecasts production streams for each year from 1996 to 2010. This figure is used as an example to demonstrate the fivefold increase in the usage of satellite data over this time period.  Figure reference: &lt;em&gt;Cubasch, U., D. Wuebbles, D. Chen, M.C. Facchini, D. Frame, N. Mahowald and J.-G. Winther, 2013: Introduction. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.&lt;/em&gt;&#xA;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;¹&lt;sup&gt;Research aircraft sometimes do.  Flying in a full-sized jet 20 metre above the ocean surface is an interesting experience!&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2014-05-08T14:48:14.163" LastActivityDate="2016-07-14T01:20:59.017" Title="Why are weather kites no longer used (much) operationally?" Tags="|measurements|weather|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="9" PostTypeId="1" CreationDate="2014-04-15T19:27:53.613" Score="7" ViewCount="280" Body="&lt;p&gt;So as we know, climate change is associated with increased radiation flux into the Earth. In other words, the sum of (incoming shortwave radiation) - (outgoing longwave radiation) [which I will call net flux] is greater than 0.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm just curious though - how have all of these fluxes changed over the last 20 years? Has net flux been constantly positive over the last 20-30 years? Is it changed by El Niño? Have we seen any changes in the flux associated with the recent &quot;slowdown&quot; in global warming?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="111" LastEditDate="2014-12-21T21:40:25.713" LastActivityDate="2014-12-21T21:40:25.713" Title="How have levels of outgoing longwave and incoming shortwave radiation changed over the last 20-30 years?" Tags="|climate|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10" PostTypeId="2" ParentId="6" CreationDate="2014-04-15T19:28:51.787" Score="15" Body="&lt;p&gt;Cloud particles are suspended in air, and their movement is governed by:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Wind; whichever way the wind blows, the clouds go (with some exceptions such as lenticular clouds; thanks &lt;a href=&quot;https://earthscience.stackexchange.com/questions/6/what-determines-how-fast-clouds-move/10?noredirect=1#comment22564_10&quot;&gt;jamesqf comment&lt;/a&gt;).  The wind is often &lt;a href=&quot;https://en.wikipedia.org/wiki/Jet_stream&quot; rel=&quot;nofollow noreferrer&quot;&gt;strongest in the upper troposphere&lt;/a&gt; (there are no clouds in the upper atmosphere), so upper tropospheric clouds will move faster than near-surface clouds.&lt;/li&gt;&#xA;&lt;li&gt;Convection: strong updrafts will force particles upward, as will forced convection by wind reaching obstacles&lt;/li&gt;&#xA;&lt;li&gt;Particle size: larger particles are more likely to fall down.  Note that &quot;fall down&quot; may be used either relative to the surrounding air, or relative to the ground (i.e. precipitation that may or may not reach the ground).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So the type of cloud is indirectly relevant: different cloud types are associated with different particle sizes, are to a larger or smaller degree the consequence of convection, and are more or less likely to contain precipitation-sized particles.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2017-09-25T14:47:19.227" LastActivityDate="2017-09-25T14:47:19.227" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="11" PostTypeId="1" CreationDate="2014-04-15T19:31:07.827" Score="9" ViewCount="135" Body="&lt;p&gt;Some examples of &lt;a href=&quot;http://www.atmos.colostate.edu/ao/introduction.html&quot;&gt;annular modes&lt;/a&gt; include ENSO, NAM, and SAM. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think one of the major mysteries of them is how they formed to begin with.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm just curious - do we have any idea of whether or not these annular modes existed in paleoclimates, particularly around the time of Pangaea? Do we have the computational power to predict them?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="87" LastEditDate="2014-06-05T08:43:01.567" LastActivityDate="2014-06-05T08:43:01.567" Title="Can we predict which annular modes existed during the time of Pangaea?" Tags="|atmosphere|paleoclimatology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12" PostTypeId="1" AcceptedAnswerId="136" CreationDate="2014-04-15T19:33:46.327" Score="12" ViewCount="1363" Body="&lt;p&gt;So on land, I believe that one factor in their formation is due to inhomogeneities in surface heating between land and ocean (and also inhomogeneities in surface heating due to terrain effects like the Rocky Mountains).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But what about in the ocean, where we don't see such inhomogeneities? How is the formation and movement of Rossby Waves in ocean different from that of land?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="6129" LastEditDate="2020-05-08T17:02:29.847" LastActivityDate="2023-08-04T15:36:21.847" Title="How do Rossby Waves in the ocean form?" Tags="|geophysics|oceanography|waves|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13" PostTypeId="1" CreationDate="2014-04-15T19:38:24.553" Score="6" ViewCount="132" Body="&lt;p&gt;So we know that the air temperature at higher elevations is lower. But is the air temperature at a certain isobar over, say Vail, Colorado, higher than the air temperature of the same isobar over, say, New York City?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And more importantly, do these differences in air temperature along the same isobar affect the large-scale atmospheric circulation?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="725" LastEditDate="2014-11-27T11:38:17.533" LastActivityDate="2014-11-27T11:38:17.533" Title="Are certain isobar temperatures higher in mountainous regions?" Tags="|atmosphere|temperature|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="14" PostTypeId="2" ParentId="9" CreationDate="2014-04-15T19:40:24.720" Score="6" Body="&lt;p&gt;&lt;em&gt;Have we seen any changes in the flux associated with the recent &quot;slowdown&quot; in global warming?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is no evidence for such a slowdown, nor for a change in the associated flux.  &lt;em&gt;Atmospheric&lt;/em&gt; warming has not been significant in the past 15 years (nor can we significantly state that it hasn't warmed), ocean warming has continued.  As the oceans absorb the vast majority of the excess heat, this net flux probably has not significantly changed during the &quot;slowdown&quot;.  Note that 15 years is in any case too short to state anything about global climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for your other questions: &lt;em&gt;estimates&lt;/em&gt; of the flux have certainly changed over the past 20 years. but estimates vary quite a bit, so I don't think we can significantly state that there has been a change in the fluxes over the past 20 years.  Nor can we state the reverse; it appears further research is needed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For an excellent and still somewhat recent overview article on the topic, see:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://citeseerx.ist.psu.edu/viewdoc/download?rep=rep1&amp;amp;type=pdf&amp;amp;doi=10.1.1.210.2513&quot;&gt;Trenberth et al., Earth's Global Energy Budget, BAMS 2009&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2014-04-15T19:53:12.420" LastActivityDate="2014-04-15T19:53:12.420" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="15" PostTypeId="1" AcceptedAnswerId="18" CreationDate="2014-04-15T19:41:22.853" Score="9" ViewCount="1619" Body="&lt;p&gt;Are the pole-to-equator temperature gradients lower at higher heights than at lower heights (like 850 mb/500 mb)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If so, why is it the case? Especially given that the zonal circulation tends to be much higher at higher heights, so one could expect there to be less &lt;a href=&quot;https://en.wikipedia.org/wiki/Meridional_flow&quot; rel=&quot;nofollow&quot;&gt;meridional&lt;/a&gt; heat transport.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Bonus question: how is it different in other planetary atmospheres?)&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="725" LastEditDate="2014-11-27T11:40:14.733" LastActivityDate="2014-11-27T11:40:14.733" Title="How does the pole-to-equator temperature gradient scale with height contours?" Tags="|atmosphere|meteorology|temperature|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="16" PostTypeId="1" CreationDate="2014-04-15T19:50:54.113" Score="14" ViewCount="1592" Body="&lt;p&gt;The oceans are absorbing much of the heat from climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How is all of this heat measured?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="284" LastEditDate="2014-05-21T03:05:48.943" LastActivityDate="2014-10-07T09:38:18.293" Title="How is ocean heat content measured?" Tags="|ocean|oceanography|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="17" PostTypeId="1" CreationDate="2014-04-15T19:52:31.040" Score="18" ViewCount="2144" Body="&lt;p&gt;A common layman explanation for &lt;em&gt;why does it get colder to higher elevations&lt;/em&gt; (considering only the troposphere here) qualitatively boils down to &lt;em&gt;The Sun heats the Earth's surface and the Earth's surface heats the atmosphere&lt;/em&gt;.  I remember that, every time I heard or read this explanation as a child, I thought: then why is the Tibetan plateau still colder than lowlands at the same latitude?  After all, the solar energy reaching the surface in Tibet is no less.  Clearly there is more to it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Considering a remark from a quantum physics lecturer that &lt;em&gt;you only really understand something after you've taught the subject twice&lt;/em&gt;, I'm phrasing my question as such: How does one explain, in layman terms, why the Tibetan plateau is colder than lowlands at similar latitudes?&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorDisplayName="user1066" LastEditDate="2019-03-05T01:39:45.660" LastActivityDate="2019-03-05T01:39:45.660" Title="How do I explain why the Tibetan plateau is colder than lowlands at similar latitudes?" Tags="|meteorology|atmosphere|temperature|climatology|tibetan-plateau|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="18" PostTypeId="2" ParentId="15" CreationDate="2014-04-15T20:04:30.393" Score="13" Body="&lt;p&gt;It depends on the season. The figures below shows zonal mean temperature for June-July-August &lt;a href=&quot;http://old.ecmwf.int/research/era/ERA-40_Atlas/docs/section_D25/parameter_zmtsp.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;from ECMWF ERA-40 reanalysis&lt;/a&gt;.  As you can see, at 100 hPa, the equator is actually &lt;em&gt;colder&lt;/em&gt; than the sunlit hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;June-July-August&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/nBQBX.gif&quot; alt=&quot;Zonally averaged temperature&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;December-January-February&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/fT5At.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For getting the &quot;facts&quot; on this kind of questions, the &lt;a href=&quot;http://old.ecmwf.int/research/era/ERA-40_Atlas/docs/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ECMWF ERA-40 atlas&lt;/a&gt; is a good source.  Now as to &lt;em&gt;why&lt;/em&gt; this is the case; that is a much more involved question on atmospheric dynamics and circulation.  The Earth heats the surface, in particular where it's sunlit.  It also heats the spring and summer stratosphere, where ozone absorbs solar radiation.  Heating causes air to rise from the surface to the tropopause, where it's forced poleward creating a &lt;a href=&quot;https://en.wikipedia.org/wiki/Hadley_cell&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hadley cell&lt;/a&gt;.  Meanwhile, the Earth rotates and everything becomes a highly chaotic and dynamical system.  So the fact that winds are strongest near the tropopause (see, for example, &lt;a href=&quot;http://old.ecmwf.int/research/era/ERA-40_Atlas/images/full/D25_XS_DJF.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;DJF winds&lt;/a&gt;) is not a direct consequence of where the heating occurs, but rather the effect of a lot of dynamics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For further reading on why atmospheric circulation is as it is, one needs to study textbooks.  Some famous textbooks on dynamic meteorology and atmospheric science are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://books.google.ca/books/about/An_Introduction_to_Dynamic_Meteorology.html?id=fhW5oDv3EPsC&quot; rel=&quot;nofollow noreferrer&quot;&gt;James Holton, An Introduction to Dynamic Meteorology&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://books.google.ca/books?id=HZ2wNtDOU0oC&amp;amp;redir_esc=y&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wallace &amp;amp; Hobbs, Atmospheric Science: An Introductory Survey&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2014-05-13T23:36:02.877" LastActivityDate="2014-05-13T23:36:02.877" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="19" PostTypeId="1" AcceptedAnswerId="56" CreationDate="2014-04-15T20:15:10.483" Score="32" ViewCount="4549" Body="&lt;p&gt;We use different weather models all the time, such as the &lt;a href=&quot;http://en.wikipedia.org/wiki/Integrated_Forecast_System&quot;&gt;ECMWF&lt;/a&gt; and the &lt;a href=&quot;http://en.wikipedia.org/wiki/Global_Forecast_System&quot;&gt;GFS&lt;/a&gt;. These models are simply &lt;em&gt;amazing&lt;/em&gt; to me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How do these models work? I know they have to take in various data points - what are these, and how does the model use it? Also, how do they come up with a forecast or a map of what will happen in the future?&lt;/p&gt;&#xA;" OwnerUserId="20" LastEditorUserId="192" LastEditDate="2015-03-08T23:16:11.270" LastActivityDate="2015-03-08T23:16:11.270" Title="How do weather models work?" Tags="|meteorology|models|weather-forecasting|nwp|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="20" PostTypeId="1" AcceptedAnswerId="74" CreationDate="2014-04-15T20:20:25.937" Score="22" ViewCount="5933" Body="&lt;p&gt;Some weather models include GFS (&lt;a href=&quot;https://en.wikipedia.org/wiki/Global_Forecast_System&quot; rel=&quot;noreferrer&quot;&gt;Global Forecast System&lt;/a&gt;) and NAM (&lt;a href=&quot;https://en.wikipedia.org/wiki/North_American_Mesoscale_Model&quot; rel=&quot;noreferrer&quot;&gt;North American Mesoscale Model&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some climate models include CCSM (&lt;a href=&quot;https://en.wikipedia.org/wiki/Community_Climate_System_Model&quot; rel=&quot;noreferrer&quot;&gt;Community Climate System Model&lt;/a&gt;) and the NASA GISS (&lt;a href=&quot;http://www.giss.nasa.gov/projects/gcm/&quot; rel=&quot;noreferrer&quot;&gt;Goddard Institute for Space Studies&lt;/a&gt;) model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the differences in the types of physics, parameterizations, and other properties that they use?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="94" LastEditDate="2015-11-20T10:28:06.523" LastActivityDate="2015-11-20T10:28:06.523" Title="What are the major differences between weather models and climate models?" Tags="|meteorology|atmosphere|climate|models|weather-forecasting|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="21" PostTypeId="1" CreationDate="2014-04-15T20:29:10.783" Score="13" ViewCount="216" Body="&lt;p&gt;Kelvin waves are basically waves that balance out the Coriolis force against topographic boundaries like coastlines and mountains. It seems very important in the oceans, for example.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is this: are Kelvin waves important in determining the surface temperature variations of regions that are, for example, on the west side of mountain slopes like the Andes or Rockies?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="200" LastEditDate="2015-02-04T18:25:28.353" LastActivityDate="2015-02-04T18:25:28.353" Title="How do Kelvin waves determine surface temperature variations?" Tags="|atmosphere|ocean|waves|atmosphere-modelling|coriolis|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="22" PostTypeId="1" AcceptedAnswerId="26" CreationDate="2014-04-15T20:33:48.477" Score="16" ViewCount="598" Body="&lt;p&gt;So global warming will increase the tropospheric temperatures, which, in turn, would make the clouds higher than they otherwise would be.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And higher clouds (especially cirrus clouds) tend to trap in more long-wave radiation. It's the low clouds (like marine stratus) that reflect away incoming shortwave radiation while not trapping in more long-wave radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my question is this: would global warming increase these feedback effects due to increasing the cloud heights? (and perhaps decreasing the amount of marine stratus clouds?) If status clouds gave way to cumulus clouds, what would be their net effects on Earth's radiative budget?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="124" LastEditDate="2014-04-19T06:59:30.727" LastActivityDate="2014-04-19T06:59:30.727" Title="How will cloud feedback effects on the climate change as the result of global warming?" Tags="|atmosphere|meteorology|climate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="23" PostTypeId="1" CreationDate="2014-04-15T20:35:07.193" Score="3" ViewCount="114" Body="&lt;p&gt;Large-scale patterns of climate variability can be explained at this &lt;a href=&quot;http://www.atmos.colostate.edu/ao/introduction.html&quot; rel=&quot;nofollow&quot;&gt;Annular Modes Website&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If so, have they been characterized by EOF analysis in the same way that the annular modes in the atmosphere have been characterized? Where would be able to find this?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="111" LastEditDate="2016-09-16T14:57:06.910" LastActivityDate="2016-09-16T14:57:06.910" Title="Do large-scale modes of variability (like NAM/SAM/ENSO) exist in the ocean?" Tags="|ocean|enso|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="24" PostTypeId="1" CreationDate="2014-04-15T20:37:49.747" Score="16" ViewCount="409" Body="&lt;p&gt;The lapse rate is the rate at which temperature decreases with height. By &quot;3D&quot; distribution, I mean distribution across all latitudes, longitudes, and heights.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would climate change change the lapse rate more in the poles than the tropics? Would increased humidity be the main reason, or could there be other causes as well? &lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="725" LastEditDate="2014-11-27T11:45:33.833" LastActivityDate="2016-10-31T17:33:26.800" Title="How will climate change affect the 3D distribution of lapse rate in the atmosphere?" Tags="|atmosphere|climate-change|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="25" PostTypeId="1" CreationDate="2014-04-15T20:39:10.967" Score="9" ViewCount="364" Body="&lt;p&gt;Just as importantly, how do we measure the heat that's transported from the surface layer into the twilight zone and deep oceans?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="4487" LastEditDate="2015-11-08T21:04:29.120" LastActivityDate="2015-11-08T21:04:29.120" Title="How does heat get transported between the surface layer, twilight zone, and the deep ocean?" Tags="|ocean|oceanography|ocean-currents|salinity|ocean-models|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="26" PostTypeId="2" ParentId="22" CreationDate="2014-04-15T20:39:49.863" Score="21" Body="&lt;p&gt;&lt;strong&gt;We don't really know.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Climate models agree that the feedback is profound.  Significant.  Unfortunately, they do not agree about the magnitude of the feedback.  Nor about the sign.  The problem is that there are competing feedbacks.  Clouds act similar to greenhouse gases, because they absorb and re-emit terrestrial radiation.  But they also reflect solar radiation.  These feedbacks compete, and both have a large uncertainty.  The net effect is the difference between the two, and the difference between two quantities with a large uncertainty, has a very large uncertainty.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a major topic of research and it has been a major source of uncertainty in global climate models for... decades.  A major paper on the topic, a bit old but still mostly true, is:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Stephens, Graeme L., 2005: Cloud Feedbacks in the Climate System: A Critical Review. J. Climate, 18, 237–273. doi: &lt;a href=&quot;http://dx.doi.org/10.1175/JCLI-3243.1&quot; rel=&quot;noreferrer&quot;&gt;http://dx.doi.org/10.1175/JCLI-3243.1&lt;/a&gt; &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Quoting from this article, published in 2005:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Thus we have no clear theory that suggests the accumulated effects of cloud feedbacks are in any way a function of global-mean temperature or, as posed, ΔT.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And from IPCC AR4 WG1, published in 2007:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Cloud feedbacks remain the largest source of uncertainty in climate sensitivity estimates.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The most state-of-the-art knowledge at the time of writing is summarised in &lt;a href=&quot;http://www.climatechange2013.org/images/report/WG1AR5_Chapter07_FINAL.pdf&quot; rel=&quot;noreferrer&quot;&gt;IPCC AR5 WG1 chapter 7&lt;/a&gt; (PDF), which stated in 2013:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Owing to the large magnitudes of the SWCRE [short wave cloud radiative effect] and LWCRE [long wave cloud radiative effect], clouds have the potential to cause significant climate feedback (Section 7.2.5). The sign of this feedback on climate change cannot be determined from the sign of CRE [cloud radiative effect] in the current climate, but depends instead on how climate-sensitive the properties are that govern the LWCRE and SWCRE.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Does that mean we can say nothing?  Well, it's not quite so pessimistic.  There are many attempts to answer this question.  The figure below shows estimates for the regional distribution of the shortwave and longwave cloud radiative effect, again from AR5 WG1:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/ltbg8.jpg&quot; alt=&quot;AR5 WG1 Fig 7.7&quot;&gt;&#xA;&lt;br /&gt;&#xA;&lt;sup&gt;Figure 7.7 | Distribution of annual-mean top of the atmosphere (a) shortwave, (b) longwave, (c) net cloud radiative effects averaged over the period 2001–2011 from the Clouds and the Earth’s Radiant Energy System (CERES) Energy Balanced and Filled (EBAF) Ed2.6r data set (Loeb et al., 2009) and (d) precipitation rate (1981–2000 average from the GPCP version 2.2 data set; Adler et al., 2003).  &lt;em&gt;Figure reference:  Boucher, O., D. Randall, P. Artaxo, C. Bretherton, G. Feingold, P. Forster, V.-M. Kerminen, Y. Kondo, H. Liao, U. Lohmann, P. Rasch, S.K. Satheesh, S. Sherwood, B. Stevens and X.Y. Zhang, 2013: Clouds and Aerosols. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.&lt;/em&gt;&#xA;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This suggests the effect is negative, but the debate goes on.  To be continued!&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2014-04-15T20:54:44.620" LastActivityDate="2014-04-15T20:54:44.620" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="27" PostTypeId="1" CreationDate="2014-04-15T20:41:39.313" Score="7" ViewCount="356" Body="&lt;p&gt;E.g. How could I calculate the average temperature anomaly between, say, Boulder, CO and all other locations along the 40N parallel?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What about Boulder, CO, and all other locations along 40N at Boulder's altitude?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What datasets would I need, and what resolution would they have? What would be the advantages/disadvantages of these datasets?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="81" LastEditDate="2014-04-16T15:17:13.540" LastActivityDate="2014-04-16T15:17:13.540" Title="How can I calculate the average latitudinal temperature anomaly between a city and all other locations along the city's latitude?" Tags="|weather|temperature|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="28" PostTypeId="1" CreationDate="2014-04-15T20:43:55.260" Score="7" ViewCount="265" Body="&lt;p&gt;E.g. are the clouds on Venus (and Titan) cumulus, stratus, cirrus, or some other type that isn't found on Earth?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="87" LastEditDate="2014-04-16T14:44:48.687" LastActivityDate="2014-05-07T03:19:01.407" Title="Can the clouds on Venus and Titan be categorized in the same way as clouds on Earth?" Tags="|atmosphere|planetology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="29" PostTypeId="1" CreationDate="2014-04-15T20:48:35.120" Score="14" ViewCount="807" Body="&lt;p&gt;This is similar to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/16/how-is-ocean-heat-uptake-measured&quot;&gt;How is ocean heat content measured?&lt;/a&gt;, but here I'm thinking about the total content rather than fluxes in the content between land and ocean.&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2018-11-25T14:01:35.647" Title="How do we measure the total heat content contained in ocean and atmosphere?" Tags="|atmosphere|ocean|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="30" PostTypeId="1" CreationDate="2014-04-15T20:51:00.823" Score="7" ViewCount="265" Body="&lt;p&gt;In particular, how it will affect the eddy and zonal components of kinetic energy in the atmosphere?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(I'm also curious about potential energy, though that could come in another question)&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="725" LastEditDate="2014-11-27T11:47:38.077" LastActivityDate="2014-11-27T11:47:38.077" Title="How will climate change affect the total kinetic energy in the atmosphere?" Tags="|atmosphere|climate-change|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="31" PostTypeId="1" CreationDate="2014-04-15T20:53:13.413" Score="10" ViewCount="203" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Marine_snow&quot; rel=&quot;noreferrer&quot;&gt;Marine snow&lt;/a&gt; in the deep ocean is a continuous shower of mostly organic detritus falling from the upper layers of the water column.  How much carbon is sequestered in this process? How does it compare with the amount of carbon sequestered through plants?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm also curious: what percent of this carbon sequestration comes from plankton and what percent from fish? Do seabirds reduce this carbon sequestration? What about marine mammals?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="53" LastEditDate="2014-04-21T15:28:13.810" LastActivityDate="2017-09-19T08:09:54.680" Title="How much carbon is sequestered out of the atmosphere through marine snow?" Tags="|climate|carbon-cycle|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="32" PostTypeId="2" ParentId="20" CreationDate="2014-04-15T21:03:46.217" Score="16" Body="&lt;p&gt;This answer is not complete, but it is a start.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the most significant differences is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Weather models use measurements, whereas climate models do not&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Put another way: a weather model is an &lt;em&gt;initial value problem&lt;/em&gt;.  The initial values that go in are of essential importance for the result to be correct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A climate model solves what is primarily a &lt;em&gt;boundary value problem&lt;/em&gt;.  The initial values &lt;em&gt;should&lt;/em&gt; not matter.  In fact, climate models are &quot;spun up&quot;, that means, to determine the climate 2000–2100, the model run may start in 1950 to &lt;em&gt;get rid&lt;/em&gt; of initial values.  Then, the relevant information is not the weather or March 23, 2063; but the statistics of the weather (mean, standard deviation, etc.), over 2060–2090 (for example).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if a climate model runs 1900–2100, &lt;em&gt;it is not expected to reproduce the climate for a particular year&lt;/em&gt;.  This is commonly misunderstood, and might be taken by climate skepticists as showing that climate models don't work (for example, “&lt;em&gt;they don't reproduce the recent lack of significant atmospheric warming!&lt;/em&gt;”, not realising that &lt;em&gt;this doesn't matter&lt;/em&gt;).  Different are analysis or reanalysis (weather) models, that &lt;em&gt;do&lt;/em&gt; use measurements, and therefore &lt;em&gt;do&lt;/em&gt; represent the weather in a particular year accurately.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As stated before, this is only a partial answer.  There are many more important differences, but this is one of the most important ones.&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2014-04-15T21:03:46.217" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="33" PostTypeId="2" ParentId="19" CreationDate="2014-04-15T21:11:18.943" Score="13" Body="&lt;p&gt;This is not a complete answer.  One aspect of weather models consists of &lt;em&gt;Data assimilation&lt;/em&gt; or &lt;em&gt;4D-var&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I agree that they are amazing, and the question &lt;em&gt;how do they work&lt;/em&gt; is too broad to be answered.  So I recommend you read up on &lt;a href=&quot;https://en.wikipedia.org/wiki/Data_assimilation&quot; rel=&quot;noreferrer&quot;&gt;data assimilation&lt;/a&gt; and in particular &lt;a href=&quot;http://old.ecmwf.int/newsevents/training/rcourse_notes/DATA_ASSIMILATION/ASSIM_CONCEPTS/Assim_concepts11.html&quot; rel=&quot;noreferrer&quot;&gt;4D-Var&lt;/a&gt;.  Concepts are &lt;em&gt;somewhat&lt;/em&gt; similar in inverse theory, but of much higher dimensionality.  In a tiny nutshell:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;At each time step and grid point, the model has a &lt;em&gt;background&lt;/em&gt; consisting of the latest information it has on the entire atmosphere (and ocean!).  This is a huge quantity of information.&lt;/li&gt;&#xA;&lt;li&gt;Then, every six hours or so, it feeds in a big chunk of information from measurements.  It uses a Bayesian method (see the 4D-Var link above) to combine the background and the measurements to make a &lt;em&gt;new&lt;/em&gt; estimate of the state of the atmosphere.&lt;/li&gt;&#xA;&lt;li&gt;Measurements are, naturally, only available for the present and past.  The rest is basically extrapolation.  But to get a good estimate, the model run starts at some time in the past; so the first part of the forecast is actually for the past or present (they don't show you that one in the models ;-).  &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Can't go into detail, but it's true, they are amazing!&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2015-03-08T17:26:59.910" LastActivityDate="2015-03-08T17:26:59.910" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="34" PostTypeId="1" CreationDate="2014-04-15T21:24:00.727" Score="12" ViewCount="7850" Body="&lt;p&gt;It is said that carbon dioxide levels were much higher during the Cretaceous and Eocene periods: which proxies are used to determine paleo-pCO&lt;sub&gt;2&lt;/sub&gt;?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="725" LastEditDate="2014-11-27T11:48:52.560" LastActivityDate="2021-09-28T12:10:57.507" Title="How were we able to measure carbon dioxide levels in earlier climates?" Tags="|climate|paleoclimatology|carbon-cycle|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="35" PostTypeId="1" CreationDate="2014-04-15T21:29:15.677" Score="14" ViewCount="308" Body="&lt;p&gt;Do we have a graph of how sedimentation rates changed over time?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="725" LastEditDate="2016-01-22T10:38:19.733" LastActivityDate="2016-01-22T16:41:09.780" Title="How have global sedimentation rates changed over the last billion years?" Tags="|geology|earth-history|sedimentology|stratigraphy|erosion|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="36" PostTypeId="2" ParentId="34" CreationDate="2014-04-15T21:31:35.693" Score="11" Body="&lt;p&gt;One method is through &lt;a href=&quot;https://en.wikipedia.org/wiki/Ice_core&quot;&gt;ice cores&lt;/a&gt; from the worlds ice caps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each year, as small amounts of snow accumulate on ice caps such as on Antarctica and Greenland, bubbled of air gets trapped.  As we drill through the ice, we can identify the air samples in those trapped bubbles, and measure directly the composition of the air in those bubbled.  It tells us much more than the level of CO₂.  For example, the ratio of isotopes of oxygen is &lt;a href=&quot;https://en.wikipedia.org/wiki/Paleothermometer&quot;&gt;a pretty good thermometer&lt;/a&gt;.  We can also see pollen, volcanic ash, and other things.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other methods are listed at the &lt;a href=&quot;https://en.wikipedia.org/wiki/Proxy_%28climate%29&quot;&gt;Wikipedia article on climate proxies&lt;/a&gt;.  Most famous are ice cores and tree rings, but other methods are lake and ocean sediments, corals, and others.  Those methods are somewhat independent so if they confirm each other, that is good.  Errors on timing may get larger if one gets further back, and sometimes a new analysis leads too a change in timing estimates.  But for the period where we have comparable records (for example, the period for which written historical records exist), results compare pretty well!&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2014-04-15T21:31:35.693" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="37" PostTypeId="1" CreationDate="2014-04-15T21:33:27.373" Score="7" ViewCount="118" Body="&lt;p&gt;Could it be measured by taking the Laplacian over all tiles and then averaging it, for example?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(this question can be relevant for both surface topography and ocean bathymetry).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think measuring it relative to Earth's geopotential would be fine.&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="10" LastEditDate="2014-04-15T22:47:06.107" LastActivityDate="2014-04-15T22:47:06.107" Title="How do we measure the total amount of variation in height of Earth's topography?" Tags="|geomorphology|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="38" PostTypeId="1" AcceptedAnswerId="98" CreationDate="2014-04-15T21:35:21.057" Score="8" ViewCount="140" Body="&lt;p&gt;Do we have any rough indices of how this flux has changed? I'm particularly interested in knowing whether the flux was higher or lower during the time of Pangaea, or during the time of the unusually warm Eocene (or at least up to the earliest time that this flux can been measured from).&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="111" LastEditDate="2015-01-23T16:05:55.983" LastActivityDate="2015-01-23T16:05:55.983" Title="How has river to ocean flux changed over the last 500 million years?" Tags="|ocean|paleoclimatology|rivers|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="39" PostTypeId="1" AcceptedAnswerId="65" CreationDate="2014-04-15T21:39:03.143" Score="12" ViewCount="285" Body="&lt;p&gt;As an example of an atmospheric river, see &lt;a href=&quot;http://www.wired.com/2014/03/california-atmospheric-river-rain/&quot;&gt;http://www.wired.com/2014/03/california-atmospheric-river-rain/&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These events have been known to hit areas like California and Bergen, Norway.&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="725" LastEditDate="2014-11-27T11:54:45.583" LastActivityDate="2014-11-27T11:54:45.583" Title="Why is heavy precipitation from atmospheric rivers more likely to hit the West Coasts than the East Coasts?" Tags="|meteorology|climate|precipitation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="40" PostTypeId="2" ParentId="34" CreationDate="2014-04-15T21:39:49.687" Score="10" Body="&lt;p&gt;Huh, this is a very interesting question. According to &lt;a href=&quot;http://www.pnas.org/content/99/7/4167.full&quot; rel=&quot;nofollow&quot;&gt;a research paper&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The long-term carbon cycle is controlled by chemical weathering,&#xA;  volcanic and metamorphic degassing, and the burial of organic carbon&#xA;  (1, 2). Ancient atmospheric carbon dioxide levels are reflected in the&#xA;  isotopic content of organic carbon (3) and, less directly, strontium&#xA;  (4) in marine sedimentary rocks; the former because photosynthetic&#xA;  carbon isotope fractionation is sensitive to CO&lt;sub&gt;2&lt;/sub&gt; levels, and the&#xA;  latter because weathering and degassing are associated with extreme&#xA;  values of the abundance ratio &lt;sup&gt;87&lt;/sup&gt;Sr/&lt;sup&gt;86&lt;/sup&gt;Sr. However, attempts to use&#xA;  these geochemical signals to estimate past CO&lt;sub&gt;2&lt;/sub&gt; levels (5–8) are&#xA;  hindered by the signals' additional relationships to various tectonic&#xA;  (9, 10) and biological (11) effects. Moreover, the strontium signal&#xA;  has proven especially difficult to parse (12–15).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So sometimes, carbon and strontium can be used to measure the CO&lt;sub&gt;2&lt;/sub&gt; levels. This is because CO&lt;sub&gt;2&lt;/sub&gt; levels are reflected in carbon and strontium. However, this is hard to identify, but in the paper above, people have studied what the CO&lt;sub&gt;2&lt;/sub&gt; levels were via strontium and carbon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition, &lt;a href=&quot;http://serc.carleton.edu/microbelife/topics/proxies/paleoclimate.html&quot; rel=&quot;nofollow&quot;&gt;sometimes ice cores in the Arctic will be drilled&lt;/a&gt;, because they trap air bubbles from long ago. Scientists can then measure the amounts of various contents in this air, including CO&lt;sub&gt;2&lt;/sub&gt;. They can represent atmospheric conditions up to 160,000 years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you'd like a more general overview of climate proxies, I'd recommend &lt;a href=&quot;http://serc.carleton.edu/microbelife/topics/proxies/paleoclimate.html&quot; rel=&quot;nofollow&quot;&gt;reading this website.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20" LastEditorUserId="67" LastEditDate="2014-05-27T10:49:59.890" LastActivityDate="2014-05-27T10:49:59.890" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="41" PostTypeId="1" AcceptedAnswerId="55" CreationDate="2014-04-15T21:42:10.540" Score="20" ViewCount="763" Body="&lt;p&gt;We know that vegetation sequesters CO&lt;sub&gt;2&lt;/sub&gt; in its leaves. Much of this carbon sequestration is temporary, since when the plant dies, much of it is released back into the atmosphere as CO&lt;sub&gt;2&lt;/sub&gt;. If it dies in a frozen region, it could be sequestered in permafrost, but even that can be released back.&lt;/p&gt;&#xA;&lt;p&gt;What if it dies, and some of the carbon gets carried into a river, which could then deposit its carbon into the ocean basins?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="6129" LastEditDate="2021-11-07T13:50:40.467" LastActivityDate="2021-11-08T05:32:14.603" Title="Does vegetation contribute to long-term carbon sequestration?" Tags="|climate|oceanography|carbon-cycle|carbon-capture|" AnswerCount="5" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="42" PostTypeId="1" CreationDate="2014-04-15T21:44:33.947" Score="10" ViewCount="398" Body="&lt;p&gt;Traditionally we think of them as being caused by differences in land-sea heating.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But more recently, some researchers, like Simona Bordoni and William Boos, have argued otherwise.&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorDisplayName="user889" LastEditDate="2015-01-01T09:47:36.380" LastActivityDate="2020-09-15T18:13:25.363" Title="What are monsoons caused by?" Tags="|climate|monsoon|" AnswerCount="2" CommentCount="4" ClosedDate="2020-09-16T22:23:50.183" ContentLicense="CC BY-SA 3.0" />
  <row Id="43" PostTypeId="1" CreationDate="2014-04-15T21:46:00.840" Score="32" ViewCount="27682" Body="&lt;p&gt;Traditionally it has thought to be the Gulf Stream. But other researchers, like &lt;a href=&quot;https://www.americanscientist.org/issues/issue.aspx?id=999&amp;amp;y=0&amp;amp;no=&amp;amp;content=true&amp;amp;page=5&amp;amp;css=print&quot;&gt;Richard Seager&lt;/a&gt; and &lt;a href=&quot;http://www.nature.com/nature/journal/v471/n7340/full/nature09924.html?WT.ec_id=NATURE-20110331&quot;&gt;Tapio Schneider&lt;/a&gt;, propose different arguments as to why.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How much of a role does the Gulf Stream really play? Who is right? (or are they all at least partially right?)&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="10" LastEditDate="2014-04-15T21:51:01.233" LastActivityDate="2023-08-04T23:20:59.543" Title="Why is Europe warmer than North America at similar latitudes?" Tags="|climate|" AnswerCount="2" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="46" PostTypeId="1" CreationDate="2014-04-15T21:48:47.207" Score="5" ViewCount="64" Body="&lt;p&gt;Rivers help transport sediment from higher regions into the oceans (where it's hard to get back into the atmosphere).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And this sediment could be carbon-rich. &lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="56" LastEditDate="2014-07-02T10:40:15.450" LastActivityDate="2014-07-02T10:40:15.450" Title="Do river fluxes help contribute to long-term carbon sequestration?" Tags="|hydrology|carbon-cycle|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="48" PostTypeId="2" ParentId="43" CreationDate="2014-04-15T21:55:07.393" Score="14" Body="&lt;p&gt;The Gulf Stream is one reason why. The other is the Labrador current.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The warm &lt;a href=&quot;http://en.wikipedia.org/wiki/Gulf_stream&quot;&gt;Gulf Stream&lt;/a&gt; runs southwest to northeast, and carries warmth from the Gulf of Mexico to western Europe. Hence, this part of the world is warmer than other parts of the world where the latitudes are similar, but the currents are &quot;neutral.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cold &lt;a href=&quot;http://en.wikipedia.org/wiki/Labrador_Current&quot;&gt;Labrador current&lt;/a&gt; runs northeast to southwest along the East coast of North America, bringing &quot;arctic&quot; influences into play. Hence the East coast of North America is colder than normal for that latitude. Tapio Schneider, cited in the question, concedes as much by &lt;a href=&quot;http://www.nature.com/nature/journal/v471/n7340/full/nature09924.html?WT.ec_id=NATURE-20110331&quot;&gt;saying,&lt;/a&gt; &quot;Our results show that warm ocean waters contribute to the contrast in mid-latitude winter temperatures between eastern and western continental boundaries not only by warming western boundaries, but also by cooling eastern boundaries.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Between the two influences, Western Europe is warmer than the northeast United States at comparable latitudes. &lt;/p&gt;&#xA;" OwnerUserId="42" LastEditorUserId="42" LastEditDate="2014-05-25T21:46:00.600" LastActivityDate="2014-05-25T21:46:00.600" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="49" PostTypeId="1" AcceptedAnswerId="2940" CreationDate="2014-04-15T21:55:50.173" Score="37" ViewCount="978" Body="&lt;p&gt;My impression is that both ocean grand circulation models (e.g. &lt;a href=&quot;http://mitgcm.org/&quot; rel=&quot;noreferrer&quot;&gt;MITgcm&lt;/a&gt;), and Mantle Convection models (e.g. &lt;a href=&quot;http://geodynamics.org/cig/software/citcoms/&quot; rel=&quot;noreferrer&quot;&gt;CitcomS&lt;/a&gt;), both use Navier-Stoke's as the governing equation. What are the other major similarities between these two types of models?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Should there be more shared between these two modeling communities since they both rely on fluid dynamics?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: For those wondering why this might be important: You can use mantle convection to calculate dynamic topography, and then couple it with heatflow models to predict sea level rise. Of course, you also need to couple that with glacial melting dynamics and GCMs. &lt;a href=&quot;http://www.sciencemag.org/content/319/5868/1357.short&quot; rel=&quot;noreferrer&quot;&gt;See Muller et al., 2008&lt;/a&gt; for more information. I know there are a few geodynamicsts now working on this problem in general, but no substantial work has been published . (May 2015) &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="32" LastEditDate="2015-05-04T19:45:48.863" LastActivityDate="2016-03-26T04:04:04.623" Title="Similarities between grand circulation solvers and mantle convection solvers" Tags="|atmosphere|geophysics|ocean|models|geodynamics|" AnswerCount="2" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="50" PostTypeId="1" CreationDate="2014-04-15T21:56:36.840" Score="17" ViewCount="764" Body="&lt;p&gt;The entropy per unit mass of moist air can be defined as&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$s=(1-q_t)(C_{pd} \ln{T}-R_d\ln{p_d})+q_tC_l\ln{T} + \frac{q_vL_v}{T}-q_vR_v\ln{\mathcal{H}}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And in statistical equilibrium, the entropy budget takes this following form&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\frac{Q_{\mathrm{lat}}+Q_{\mathrm{sen}}}{T_{\mathrm{surf}}}+\frac{Q_{\mathrm{rad}}}{T_{\mathrm{rad}}}+\Delta{S}_{\mathrm{irr}}=0$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are all explained in &lt;a href=&quot;http://www.math.nyu.edu/~pauluis/Olivier_Pauluis_Homepage/Bibliography_files/Pauluis_Held_2002a.pdf&quot; rel=&quot;noreferrer&quot;&gt;this paper&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Irreversible entropy is produced from irreversible phase changes, the diffusion of water vapor, and the frictional dissipation of falling water vapor. Entropy can reduce the amount of work available to accelerate convective updrafts and downdrafts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm just wondering - how will the amount of entropy in the atmosphere change as a result of climate change? Seeing that global warming tends to decrease the pole-to-equator gradient (resulting in a more homogeneous temperature distribution), I wonder if it might increase?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="725" LastEditDate="2014-11-28T07:49:52.833" LastActivityDate="2018-10-17T14:29:27.693" Title="How will climate change affect the entropy budget of the atmosphere?" Tags="|atmosphere|climate|climate-change|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="51" PostTypeId="1" AcceptedAnswerId="87" CreationDate="2014-04-15T21:59:11.533" Score="14" ViewCount="569" Body="&lt;p&gt;Massive amounts of freshwater rests atop the world's mountains in the form of ice, snow, permafrost, and glaciers.  Many areas of the world rely upon the melting of snow and ice to recharge their rivers and reservoirs.  But not all of that ice and snow actually melts. Some percentage of a snowpack will phase change directly into water vapor (sublimation).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How much potential mountain run off is lost to sublimation anually?  How can we measure this loss?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What sort of insight do researchers have on the impacts of sublimation on the local microclimate? &lt;/p&gt;&#xA;" OwnerUserId="38" LastEditorUserId="38" LastEditDate="2014-04-16T00:20:43.177" LastActivityDate="2014-04-17T23:47:45.370" Title="What are the impacts of sublimation on an annual mountain snowpack?" Tags="|hydrology|meteorology|runoff|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="52" PostTypeId="1" CreationDate="2014-04-15T22:05:27.247" Score="11" ViewCount="829" Body="&lt;p&gt;Here's a paper on the &lt;a href=&quot;http://www.math.nyu.edu/~pauluis/Olivier_Pauluis_Homepage/Bibliography_files/Pauluis_Held_2002a.pdf&quot; rel=&quot;nofollow&quot;&gt;entropy budget&lt;/a&gt;&lt;sup&gt;1&lt;/sup&gt;, where moist entropy is defined in equation (8) as&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;$$&#xA;s = (1-q_t)(C_{pd} \ln T - R_d \ln p_d) + q_t C_l \ln T + \frac{q_v L_v}{T} - q_v R_v \ln \mathcal{H} &#xA;$$&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;In this expression, $q_v$ is the speciﬁc humidity for water vapor, $C_{pd}$ is the speciﬁc heat at constant pressure of dry air, $C_l$ is the speciﬁc heat of liquid water, $T$ is the temperature of moist air, $R_d$ and $R_v$ are the gas constants of dry air and water vapor, $p_d$ is the partial pressure of dry air, $\mathcal{H} = e/e_s$ is the relative humidity, $e$ is the water vapor pressure, and $e_s$ is the saturation vapor pressure.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm just curious: is entropy directly measured, or indirectly measured from other sources? If we measured it, what would be the spatial-temporal resolution of such a measurement?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt; Pauluis, Olivier, and Isaac M. Held. &quot;Entropy Budget of an Atmosphere in Radiative–Convective Equilibrium. Part I: Maximum Work and Frictional Dissipation.&quot; &lt;em&gt;Journal of the Atmospheric Sciences&lt;/em&gt; 59: 125-139. &lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="64" LastEditDate="2014-05-21T02:59:57.607" LastActivityDate="2018-05-18T13:32:01.977" Title="How do we measure (or empirically calculate) the amount of entropy in the atmosphere and oceans?" Tags="|meteorology|atmosphere|thermodynamics|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="53" PostTypeId="2" ParentId="46" CreationDate="2014-04-15T22:09:52.307" Score="5" Body="&lt;p&gt;Rivers generally include dissolved oxygen. Therefore any organic content in suspension will tend to dissolve. The movement of water (open to the atmosphere, etc) will tend to entrain some oxygen from the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For carbon to be preserved in sediment, it has to be buried before it can break down. Typically this would occur where water movement is minimal so that it can precipitate out and be buried by mud/sand.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Areas of water may be anoxic (eg. ocean bottom waters, or the sea bottom waters that led to the deposition of the English Kimmeridge Clay), but these areas tend to have restricted currents so that what oxygen that is available is &quot;quickly used up&quot; oxidising some of the organic material.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes you can capture carbon in sediments - that is how all fossil fuels are formed, but you have to have the right conditions. Lakes, swamps, seas are much better than running rivers themselves. A deltaic swamp with lots of organic stuff growing in situ but experiencing periodic river floods could be a good way to preserve organic material...  (cf. the Carboniferous in Europe and the US).&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Further references:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pubmed/11539298&quot; rel=&quot;nofollow&quot;&gt;Factors influencing organic carbon preservation in marine sediments.&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/030442039500008F&quot; rel=&quot;nofollow&quot;&gt;&quot;Sedimentary organic matter preservation: an assessment and speculative synthesis&quot; in Marine Chemistry Volume 49, Issues 2–3, April 1995, Pages 81–115&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Interesting research on the influence of iron's oxidation states on the oxidation of organic matter:  &lt;a href=&quot;http://www.nature.com/nature/journal/v483/n7388/full/nature10855.html&quot; rel=&quot;nofollow&quot;&gt;Preservation of organic matter in sediments promoted by iron, Lalonde et al,  Nature v483, pp198–200&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorUserId="44" LastEditDate="2014-04-16T13:40:17.470" LastActivityDate="2014-04-16T13:40:17.470" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="54" PostTypeId="2" ParentId="41" CreationDate="2014-04-15T22:17:00.243" Score="14" Body="&lt;p&gt;Unlikely but theoretically possible.&#xA;As the bits of tree work their way down to the sea, they are going to oxidise and release CO2. This would appear to our eyes as &quot;rotting&quot; and breaking down. Leaves aren't going to make it, although they might get buried in river sediments.&#xA;Trunks might. Once they reach the open sea, they are going to have to become water logged and sink to the bottom of the sea or ocean. They are going to then have to either fall into an area of anoxic bottom waters (restricted water flow =&gt; very little oxygen if any), or be quickly buried by sediment that cuts off the oxygen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Speaking generally, when I look at ocean sediments, I have yet to see fossil wood. I do see fossil wood in places like river deltaic sediments though (eg. the Carboniferous sandstones of West Yorkshire).&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2014-04-15T22:17:00.243" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="55" PostTypeId="2" ParentId="41" CreationDate="2014-04-15T22:24:37.847" Score="14" Body="&lt;p&gt;This has been in the news in the last week or so here in Canada:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Hippie Carbon offset business: &lt;a href=&quot;http://www.edmontonjournal.com/technology/2013+Couple+converts+family+land+carbon+farm/8328600/story.html&quot; rel=&quot;nofollow&quot;&gt;2013: Couple converts family land to ‘carbon farm’.&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Using more wood in buildings from quick growing farmed trees as a long-term sequestration: &lt;a href=&quot;http://www.economist.com/blogs/babbage/2014/04/wooden-skyscrapers&quot; rel=&quot;nofollow&quot;&gt;Wooden skyscrapers.&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;From the Kyoto rules on what counts in this space, this document provides some good details also with respect to Canada: &lt;a href=&quot;http://www.mnr.gov.on.ca/stdprodconsume/groups/lr/@mnr/@climatechange/documents/document/276909.pdf&quot; rel=&quot;nofollow&quot;&gt;The Ministry protects Ontario’s biodiversity while promoting economic opportunities in the resource sector and supporting outdoor recreation opportunities.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thoughts on this space: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Re-vegetation should eventually hit steady-state but most of the approaches rely on the substantial deforestation that has already happened worldwide - regaining this often unused former farmland for forests increase the overall per-km^2 biomass and thus increases the overall size of the biomass carbon sink of earth.&lt;/li&gt;&#xA;&lt;li&gt;Farming fast growth biomass (some types of trees, bamboo, etc) for new/hybrid building materials has some promise as this unnaturally ties up this carbon in a much longer cycle (steady-state is pushed much further out - so an improvement) and ideally reduces dependance on things like steel.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Getting to your question: the idea that rivers and oceans suck in organic matter and delay the time before which it becomes re-released into the atmosphere is certainly true in the same type of way, but is something else which has a steady-state as well (or at least one which does not see mass amounts of biomass sent into the oceans and rivers and destroying them as they rot and change the water chemistry). In short I do not think there is much of an argument there for this aspect as something meaningful/measurable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good thought exercise though: If I cut down the entire continent of trees and replanted them, dumping all the cut biomass into the ocean - what would the net effect be?&lt;/p&gt;&#xA;" OwnerUserId="46" LastEditorUserId="6093" LastEditDate="2016-07-18T13:11:22.920" LastActivityDate="2016-07-18T13:11:22.920" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="56" PostTypeId="2" ParentId="19" CreationDate="2014-04-15T22:30:36.593" Score="30" Body="&lt;p&gt;All numerical atmospheric models are built around calculations derived from &lt;a href=&quot;http://en.wikipedia.org/wiki/Primitive_equations&quot;&gt;primitive equations&lt;/a&gt; that describe atmospheric flow. Vilhelm Bjerknes discovered the relationships and thereby became the father of numerical weather prediction. Conceptually, the equations can be thought of as describing how a parcel of air would move in relationship to its surroundings. For instance, we learn at a young age that hot air rises. The &lt;a href=&quot;http://en.wikipedia.org/wiki/Hydrostatic_pressure#Hydrostatic_pressure&quot;&gt;hydrostatic&lt;/a&gt; vertical momentum equation explains why &lt;em&gt;and&lt;/em&gt; quantifies under what condictions hot air would stop rising. (As the air rises it expands and cools until it reaches hydrostatic equilibrium.) The other equations consider other types of motion and heat transfer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, the equations are nonlinear, which means that you can't simply plug in a few numbers and get useful results. Instead, weather models are simulations which divide the atmosphere into three-dimensional grids and calculate how matter and energy will flow from one cube of space into another during discrete time increments. Actual atmospheric flow is continuous, not discrete, so by necessity the models are approximations. Different models make different approximations appropriate to their specific purpose.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Numerical models have been improving over time for several reasons:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;More and better input data,&lt;/li&gt;&#xA;&lt;li&gt;Tighter grids, and&lt;/li&gt;&#xA;&lt;li&gt;Better approximations.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Increasing computational power has allowed models to use smaller grid boxes. However, the number of computations increases exponentially with the number of boxes and the process suffers &lt;a href=&quot;http://en.wikipedia.org/wiki/Finite_difference_method#Accuracy_and_order&quot;&gt;diminishing returns&lt;/a&gt;. On the input end of things, more and better sensors improve the accuracy of the initial conditions of the model. &lt;a href=&quot;http://en.wikipedia.org/wiki/Synoptic_scale_meteorology&quot;&gt;Synoptic scale&lt;/a&gt; and &lt;a href=&quot;http://en.wikipedia.org/wiki/Mesoscale_meteorology&quot;&gt;mesoscale&lt;/a&gt; models take input from &lt;a href=&quot;http://en.wikipedia.org/wiki/General_Circulation_Model&quot;&gt;General Circulation Models&lt;/a&gt;, which helps set reasonable intial conditions. On the output end, &lt;a href=&quot;http://en.wikipedia.org/wiki/Model_output_statistics&quot;&gt;Model Output Statistics&lt;/a&gt; do a remarkable job of estimating local weather by comparing the current model state with historical data of times when the model showed similar results.  Finally, &lt;a href=&quot;http://en.wikipedia.org/wiki/Ensemble_forecasting&quot;&gt;ensemble models&lt;/a&gt; take the output of several models as input and produce a range of possibly outcomes.&lt;/p&gt;&#xA;" OwnerUserId="4" LastEditorUserId="4" LastEditDate="2014-04-15T22:37:06.100" LastActivityDate="2014-04-15T22:37:06.100" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="57" PostTypeId="1" AcceptedAnswerId="62" CreationDate="2014-04-15T22:33:58.547" Score="20" ViewCount="932" Body="&lt;p&gt;I know that they occur when energy that was previously stored is released in &lt;a href=&quot;http://en.wikipedia.org/wiki/Earthquake&quot; rel=&quot;nofollow noreferrer&quot;&gt;seismic waves.&lt;/a&gt; But how is the energy stored in the earth in the first place, and what can trigger the release of such energy?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Put another way, the above preconditions for earthquakes can be brought about by natural phenomena such as fault lines in the earth, and also by man-made phenomena such as &lt;a href=&quot;https://earthscience.stackexchange.com/questions/73/can-mining-trigger-earthquakes&quot;&gt;mining.&lt;/a&gt; What are the ways to measure/estimate the &quot;potential&quot; energy of a fault line, and the likely resulting earthquake, and what are the ways to measure/estimate the energy released by mining or other human activities, and how large an earthquake is likely to result?&lt;/p&gt;&#xA;" OwnerUserId="42" LastEditorDisplayName="user12525" LastEditDate="2019-04-20T18:08:22.723" LastActivityDate="2019-04-20T18:08:22.723" Title="How does one measure what causes earthquakes?" Tags="|geology|geophysics|earthquakes|seismology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="58" PostTypeId="1" AcceptedAnswerId="122" CreationDate="2014-04-15T22:36:48.483" Score="30" ViewCount="2352" Body="&lt;p&gt;What is the current status of the Raymo &amp;amp; Ruddiman hypothesis that the uplift of the Tibetan Plateau during the Cenozoic cooled the Earth, resulting the current ice age(*)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;cf. &lt;a href=&quot;http://www.moraymo.us/1992_Raymo_Nature.pdf&quot;&gt;Raymo, M.E. and W.F. Ruddiman (1992) Tectonic forcing of late Cenozoic climate. Nature, v. 359, p. 117-122.&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This argued that enhanced erosion rates from the uplift of the Tibetan Plateau took CO&lt;sub&gt;2&lt;/sub&gt; from the atmosphere and cooled the Earth enough for polar ice caps to form. This was popular in my undergraduate days, although there were questions about the precise timing of events, and stopping a &quot;runaway cooling&quot; event.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(*) Ice age in a geological sense, i.e. with ice caps at one or both of the poles.&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorUserId="87" LastEditDate="2014-05-08T09:34:50.247" LastActivityDate="2014-05-08T12:58:32.233" Title="What is the status of the Raymo &amp; Ruddiman idea that Tibet cooled the Earth?" Tags="|paleoclimatology|carbon-cycle|tibetan-plateau|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="59" PostTypeId="2" ParentId="16" CreationDate="2014-04-15T22:42:06.937" Score="15" Body="&lt;p&gt;The easiest way this is measured is via &lt;a href=&quot;http://en.wikipedia.org/wiki/Argo_%28oceanography%29&quot;&gt;Argo floats&lt;/a&gt;. They're probes which periodically dive into the sea, and measure the ocean heat content.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is done by calculating the formula. &lt;a href=&quot;http://www.eea.europa.eu/data-and-maps/figures/ocean-heat-content-calculated-based&quot;&gt;According to the European Environmental Agency&lt;/a&gt;, this formula is:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Ocean heat content is defined as the integrated temperature change times the density of seawater, times specific heat capacity from the surface down to the deep ocean.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This could also be done manually by calcuating out the formula, and obtaining the temperature of the seawater by using a device such as a &lt;a href=&quot;http://en.wikipedia.org/wiki/Nansen_bottle&quot;&gt;Nansen Bottle&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="20" LastActivityDate="2014-04-15T22:42:06.937" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="60" PostTypeId="1" AcceptedAnswerId="63" CreationDate="2014-04-15T22:42:09.080" Score="19" ViewCount="1105" Body="&lt;p&gt;Historically, the earth has had five &lt;a href=&quot;http://en.wikipedia.org/wiki/Ice_age&quot;&gt;&quot;Ice Ages&quot;&lt;/a&gt; Each of them lasted millions, tens of millions, or hundreds of millions of years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The last ice age reportedly ended perhaps 10,000 years ago. That seems to represent the beginning of recorded history.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Except that a period 10,000 years is a &quot;rounding error&quot; in the span of millions of years. If it was true that &quot;we haven't been in an ice age for at least 1 million years, then I would believe that we were &quot;clear&quot; of  the last one. But what is to say that the last 10,000 years isn't just an usually warm &quot;spell&quot; in what would otherwise be a cold period of say, a million years?&lt;/p&gt;&#xA;" OwnerUserId="42" LastEditorUserId="11908" LastEditDate="2019-03-14T00:43:00.727" LastActivityDate="2019-03-14T00:43:00.727" Title="How do we know that we are NOT in an &quot;Ice Age?&quot;" Tags="|climate-change|glaciology|paleoclimatology|ice-age|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="61" PostTypeId="2" ParentId="57" CreationDate="2014-04-15T22:51:26.343" Score="10" Body="&lt;p&gt;Short answer: A build up of stress between tectonic boundaries caused by a slow, but massive convecting mantle. The stress is released when the mechanical properties of the rock (moving from ductile to brittle) are overcome.  The failure of the rocks between the two lithospheric plates cause a drastic slip; a conversion between potential and kinetic energy. This energy is often viewed in the form of seismic waves, but I prefer to think of the wave forms as just a way of mathematically representing the release in energy. The correct dictation, in my opinion, is to say that energy is released by tectonic slip which is quantified and analyzed in seismic waveforms. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are other methods of relieving stress in tectonic plates such as isostatic rebound, large impacts. Two texts one might read to get a deeper understanding of earthquake mechanics are &lt;a href=&quot;http://books.google.com/books/about/Geodynamics.html?id=-nCHlVuJ4FoC&quot;&gt;Turcotte and Shubert&lt;/a&gt;  and &lt;a href=&quot;http://epsc.wustl.edu/seismology/book/&quot;&gt;Stein and Wyessesion&lt;/a&gt;. Both are upper division/lower graduate level texts. &lt;a href=&quot;http://books.google.com/books/about/The_Solid_Earth.html?id=PifkAotvTroC&quot;&gt;Fowler&lt;/a&gt; is great if you do not have a strong mathematical background (multivariate calculus). &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-04-15T22:51:26.343" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="62" PostTypeId="2" ParentId="57" CreationDate="2014-04-15T22:55:59.510" Score="14" Body="&lt;p&gt;There are a number of causes (this list is probably not complete):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Elastic Rebound of tectonic faults. This is the most common and well known. Here the energy is elastic energy stored as two blocks of rocks move against each other. There is a point where elastic deformation cannot take up the entire movement, and the rock breaks releasing the elastic energy. This is better explained here: &lt;a href=&quot;http://earthquake.usgs.gov/regional/nca/1906/18april/reid.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reid's Elastic Rebound Theory (USGS)&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Landslides/etc. These typically appear as extremely shallow earthquakes and can often be determined from seismic records.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Cavity collapses. E.g. mines, volcanic systems, caves.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Subterranean explosions / volume expansion. Eg. mining activity, atom bomb tests, volcanic activity (eg. phreatic involving water; or magma injection)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Crystalline phase changes. Fast, deep subduction zones (eg. Tonga) experience very deep earthquakes where the rocks should be too plastic for classic elastic rebound. These are usually interpreted as 'catastrophic' phase changes of olivine -&gt; spinel -&gt; perovskite, and the depths generally match. Eg. &lt;a href=&quot;ftp://ftp.gps.caltech.edu/pub/shjwei/OkhotskSea/Kirby_1991_Science.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kirby 1991&lt;/a&gt;. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="44" LastEditorUserId="44" LastEditDate="2017-02-08T16:03:37.847" LastActivityDate="2017-02-08T16:03:37.847" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="63" PostTypeId="2" ParentId="60" CreationDate="2014-04-15T23:09:52.550" Score="19" Body="&lt;p&gt;I think you're slightly confused by some of the terminology. (Caveat: I'm a geophysist, take anything I say with a grain of salt!)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We're currently in an &lt;a href=&quot;http://en.wikipedia.org/wiki/Interglacial&quot;&gt;interglacial&lt;/a&gt; during a prolonged period of &lt;a href=&quot;http://en.wikipedia.org/wiki/Greenhouse_and_icehouse_Earth&quot;&gt;icehouse climate&lt;/a&gt; (most of the Cenozoic). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;During most of the Earth's history, the overall climate tends to be much warmer and more stable on the million-year scale. These periods are referred to as &quot;greenhouse&quot; climates.  During these times, there's relatively little evidence for extensive ice sheets (either on continents or over the ocean) at the poles.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, during times of &quot;icehouse&quot; climate, the Earth becomes cooler.  Ice masses develop at the poles and due to regular preturbations in Earth's orbit (&lt;a href=&quot;http://en.wikipedia.org/wiki/Milankovich_cycles&quot;&gt;Milankovich cycles&lt;/a&gt;), continental ice sheets tend to advance and retreat.  (Assuming there are continents near the poles.)  This leads to regular glacial and interglacial periods.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Presumably, regular fluctuations in climate due to Milankovich cycles would occur during periods of greenhouse climate.  However, ice sheets cause positive feedback that amplifies the effect of the Milankovich cycles.  This is largely due to ice and snow's albedo: they reflect more sunlight back into space instead of adsorbing it.  Therefore greenhouse Milankovich cycles were probably smaller.  (There's probably a lot more to the story. I'm not an ideal person to ask.)&lt;/p&gt;&#xA;" OwnerUserId="12" LastEditorUserId="12" LastEditDate="2014-04-15T23:26:21.267" LastActivityDate="2014-04-15T23:26:21.267" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="64" PostTypeId="1" AcceptedAnswerId="177" CreationDate="2014-04-15T23:28:45.910" Score="12" ViewCount="212" Body="&lt;p&gt;Tsunamis are quite interesting, as they only happen after a large displacement of water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Usually, the waves travel quite weirdly. Sometimes there are waves which bounce off of land and go back to sea. Sometimes they go straight to land and don't bother any other pieces of land around them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So why does this happen?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why do some tsunamis go straight to land while others are spread out?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And why others take various pathways toward land or the open sea?&lt;/p&gt;&#xA;" OwnerUserId="20" LastEditorUserId="93" LastEditDate="2014-04-16T14:44:54.247" LastActivityDate="2014-04-16T18:30:18.800" Title="Why does every tsunami travel differently?" Tags="|weather|tsunami|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="65" PostTypeId="2" ParentId="39" CreationDate="2014-04-15T23:48:06.680" Score="13" Body="&lt;p&gt;Extratropical cyclones in the Northern Hemisphere rotate around the earth in the mid-latitudes in a mean westerly flow.  This means that, on average, the track of a storm between 30°-60°N moves from west to east.  Ahead of these extratropical cyclones is a strong frontal boundary with very powerful winds, sometimes up to hurricane strength near the boundary layer.  Moisture is advected (transported by wind) from the tropics (a very wet place, relatively speaking) by these powerful winds ahead of the extratropical cyclone. The moisture then creates a narrow channel of extremely moist air along the frontal boundary. Finally, the atmospheric river moves with the mean westerly flow as the frontal boundary/extratropical cyclone shifts east. &lt;strong&gt;Therefore, to answer your question, it is because extratropical cyclones on average move from west to east that ARs impact west coasts in the Northern Hemisphere.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/lKqjk.gif&quot; alt=&quot;Atmospheric River preceding Upper low in Mid-latitudes off of US West Coast&quot;&gt;&#xA;&lt;em&gt;Atmospheric River preceding Upper low in Mid-latitudes off of US West Coast&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another way to think of this is that tropical systems (those that develop between 0°-30°N) initially move from east to west in the easterlies.  Now ask yourself how often do the mid-latitude west coast's of northern hemisphere continents fall victim to category 3-4-5 hurricanes?  Caveat: remnants from weakening tropical depressions often move into the mid-latitudes before impacting these regions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/3LlCq.jpg&quot; alt=&quot;Track of tropical cyclones in the opposite direction of Atmospheric Rivers&quot;&gt;&#xA;&lt;em&gt;Track of tropical cyclones in the opposite direction of Atmospheric Rivers&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="38" LastEditorUserId="38" LastEditDate="2014-04-16T14:11:10.347" LastActivityDate="2014-04-16T14:11:10.347" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="66" PostTypeId="2" ParentId="27" CreationDate="2014-04-16T00:44:13.500" Score="9" Body="&lt;p&gt;I think you'd be looking for a &lt;em&gt;gridded&lt;/em&gt; dataset, where data has been interpolated to a grid of the Earth, rather than one that has data at particular points (eg. stations). I'm probably not the best person to recommend one particular gridded set over another, but a good start might be the Met Office's &lt;a href=&quot;http://www.metoffice.gov.uk/hadobs/hadcrut4/&quot;&gt;HadCRUT4&lt;/a&gt; set, which combines gridded surface temperature data over both land and sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I haven't looked at HadCRUT4, but I daresay it'll come (either in plain text or NetCDF format) as a lat/lon/time array (grid), and if you're interested in a particular latitude, you should just be able to read off a latitudinal row. Then you can look at it however you like: subtract the temperature of the point closest to your city from the rest to get an anomaly right across the latitude, or average the whole thing (a zonal average) and subtract the city baseline from that. Hope that helps :)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Edit:&lt;/em&gt; HadCRUT4 is a monthly dataset. If you're looking for more temporal resolution (the weather tag suggests to me that you are), I'm not sure what availability among gridded sets is like, but you could try taking a station set (eg. &lt;a href=&quot;http://www.metoffice.gov.uk/hadobs/hadisd&quot;&gt;HadISD&lt;/a&gt;, which is hourly) and gridding it yourself.&lt;/p&gt;&#xA;" OwnerUserId="66" LastEditorUserId="66" LastEditDate="2014-04-16T03:03:15.333" LastActivityDate="2014-04-16T03:03:15.333" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="67" PostTypeId="1" AcceptedAnswerId="82" CreationDate="2014-04-16T01:04:34.560" Score="12" ViewCount="475" Body="&lt;p&gt;What's the difference between sandstorms and regular storms? Are they more than just strong wind within deserts?&lt;/p&gt;&#xA;" OwnerUserId="68" LastEditorUserId="32" LastEditDate="2014-04-16T11:35:34.630" LastActivityDate="2014-05-29T20:08:36.223" Title="Are sandstorms like regular storms?" Tags="|weather|storms|desert|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="68" PostTypeId="2" ParentId="17" CreationDate="2014-04-16T01:05:06.900" Score="17" Body="&lt;p&gt;The answer is because the Earth is not a static system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Due to the ideal gas law, air cools as it rises.  This is referred to as the dry adiabatic lapse rate.  However, you are curious why every location on earth is not the same temperature at the same latitude.  We know this is not true. But why is not true?  Weather.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The earth, as with most natural phenomenon, attempts to achieve static equilibrium.  The differences in incoming and outgoing radiation leave the earth with net energy reserves that need to be balanced out.  Weather is the mechanism that the Earth uses to attempt to achieve balance. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Okay, so we know that weather is disrupting static equilibrium on earth.  But how does that work?  Wind.  Or better yet, advection.  Advection is simply the transport of an atmospheric parameter (such as moisture, temperature, or rotation) from one location to another.  So, wind can 'transport' temperature, moisture, and rotation.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You don't necessarily need a storm to advect any of these parameters. In fact, they are always in motion.  Cold air is always moving away from the poles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Still, that doesn't quite answer it, does it?  Well, imagine you are hundreds or thousands of miles away from Tibet.  You aren't in a mountainous region anymore but instead a flatlands at sea level. The environmental lapse rate is 6.5°C/1000m above this location (because we are not dealing with an air parcel).  Tibet is 4500m - 8850m high.   That would be around approximately 32.5°C of cooling at 5000m.  The air that advects into Tibet from elsewhere is on average of 32.5-50°C cooler than at sea level. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, it isn't so much that Tibet is receiving less radiation than other points at the same latitude (&lt;em&gt;its not&lt;/em&gt;). Its more that, the air at &lt;em&gt;other locations&lt;/em&gt; at the elevation of Tibet is much cooler than the air at sea level. Remember, we measure air temperature! &lt;/p&gt;&#xA;" OwnerUserId="38" LastEditorUserId="38" LastEditDate="2014-04-18T19:31:25.427" LastActivityDate="2014-04-18T19:31:25.427" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="69" PostTypeId="1" AcceptedAnswerId="451" CreationDate="2014-04-16T01:07:36.817" Score="14" ViewCount="1416" Body="&lt;p&gt;Why don't cold fronts and other steep-gradient weather effects just dissipate? Why do they last so long? Why doesn't the heat dissipate toward the cooler region?&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2014-11-28T08:17:39.017" Title="Why don't cold fronts and other steep-gradient weather effects just dissipate?" Tags="|weather|meteorology|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="70" PostTypeId="1" AcceptedAnswerId="77" CreationDate="2014-04-16T01:09:41.603" Score="26" ViewCount="8752" Body="&lt;p&gt;What do weather forecasters mean when they say &quot;50% chance of rain&quot;? &#xA;Even more confusing: weather report often says something like &quot;30% chance of rain. &gt;10mm&quot;, then the next day &quot;70% chance of rain &amp;lt;1mm&quot;. How should I deal with this information, for example, if I'm planning a picnic?&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorDisplayName="user402" LastEditDate="2014-05-06T18:44:59.673" LastActivityDate="2017-08-23T02:21:21.837" Title="What do weather forecasters mean when they say &quot;50% chance of rain&quot;?" Tags="|meteorology|weather|precipitation|statistics|weather-forecasting|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="71" PostTypeId="1" AcceptedAnswerId="80" CreationDate="2014-04-16T01:09:50.133" Score="10" ViewCount="1771" Body="&lt;p&gt;In theory, how deep can a natural formation on the surface of the Earth's crust be? What are the limits to this depth?&lt;/p&gt;&#xA;" OwnerUserId="68" LastEditorUserId="87" LastEditDate="2014-04-16T15:17:17.860" LastActivityDate="2014-04-16T15:17:17.860" Title="How deep could the surface of the Earth's crust get?" Tags="|ocean|measurements|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="72" PostTypeId="1" AcceptedAnswerId="109" CreationDate="2014-04-16T01:11:57.480" Score="33" ViewCount="1366" Body="&lt;p&gt;Approximately what proportion of the global warming seen over the the last century is attributed to anthropogenic sources?&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="56" LastEditDate="2014-04-21T22:41:04.200" LastActivityDate="2019-02-26T18:22:48.910" Title="How much of the current global warming is due to human influence?" Tags="|climate|human-influence|climate-change|global-warming|" AnswerCount="2" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="73" PostTypeId="1" AcceptedAnswerId="79" CreationDate="2014-04-16T01:15:11.930" Score="27" ViewCount="3553" Body="&lt;p&gt;Are earthquakes more common in mining regions than they would otherwise be? e.g. is the frequency of earthquakes in those regions different when mining is occurring than when it is not?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am interested in earthquakes generally, but also particularly interested in earthquakes strong enough to have damaging impacts (to life and infrastructure).&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="56" LastEditDate="2018-03-13T00:40:21.570" LastActivityDate="2018-03-13T00:40:21.570" Title="Can mining trigger earthquakes?" Tags="|earthquakes|human-influence|mining|induced-seismicity|" AnswerCount="4" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="74" PostTypeId="2" ParentId="20" CreationDate="2014-04-16T01:16:23.817" Score="20" Body="&lt;p&gt;The major differences between weather and climate models are many.  At their core lie the same set of primitive equations, but from here there are many differences.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A weather model only (skillfully) predicts about 10 days into the future, while a climate model integrates forward in time for hundreds of years.  The main difference here is that in a weather model, we care about the &lt;em&gt;when&lt;/em&gt; and &lt;em&gt;where&lt;/em&gt; of a storm or front.  In a climate model, you get weather, but you don't really care too much where or exactly when the weather is as you are looking for a long term means (e.g. a weather model cares where a hurricane is, and when/where it will impact land, whereas a climate model may only care the average number of hurricanes per year and not about where the details of those storms).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other differences:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Spatial / temporal resolution  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because climate models run for much longer into the future than a weather model, it will have more integration timesteps for the same temporal scale.  This is relaxed by increasing the model timestep, but for numerical stability reasons the higher your timestep the more coarse your spatial resolution must be.  As a result, in general, climate models run at larger temporal and spatial scales than weather models.  The coarser resolution may force more parameterizations in the climate models.  For example a 3 km weather model may explicitly resolve convection, whereas a 30 km climate model will certainly not and need to parameterize convection.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Data Assimilation (DA)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Weather and climate models vary in their use of DA.  The biggest difference is how DA is used to &quot;spin up&quot; the model to the initialization time.  For weather models, if DA is used at all, you may only have a few DA steps spaced a few hours apart before the model starts integrating into the future.  For a climate model the DA period may be 100 years long before the present time is reached and forecasting begun.   However:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This incorporation [of DA into climate models] occurs at a number of stages of the model development, including parametrization of sub-grid scale effects and model tuning. The process is not, however, done systematically and current practice is not thought of as &quot;data assimilation.&quot;  There seems to be a growing realization that DA will have a significant role to play in future climate model development. This is, in part, driven by the need to quantify uncertainty in the model predictions. Nevertheless, there is not a consensus as to how DA should be used in these large-scale climate models. (source: &lt;a href=&quot;http://www.samsi.info/working-groups/data-assimilation-ipcc-level-models-climate-uq&quot; rel=&quot;noreferrer&quot;&gt;http://www.samsi.info/working-groups/data-assimilation-ipcc-level-models-climate-uq&lt;/a&gt; )&lt;/p&gt;&#xA;&lt;/blockquote&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Coupled models  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Weather models may represent the ocean as a parameterized surface flux (of momentum, moisture, etc) or perhaps handle it through data assimilation.  Climate models typically couple the atmosphere model to an ocean model and simulate the ocean as well.  The climate models in actuality are typically suites of models that all communicate with each other.  You may have a model for atmosphere, one for soil, one for ocean, one for vegetation, one for chemistry, etc.  A weather model may have these features, but typically as parameterizations.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Spatial coverage  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Weather models vary from global models to very localized regional models, which can in some cases be very idealized.  Climate models tend to be global.  This doesn't change the physics involved, but can influence the specific forms of the equations.  A global model will solve in spherical coordinates and many use spectral methods.  Regional weather models will use Cartesian coordinates and may make other assumptions that simplify the physics for the specific purpose the model (e.g. a storm scale idealized weather model may neglect Coriolis).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="64" LastEditorUserId="543" LastEditDate="2015-09-18T03:38:39.960" LastActivityDate="2015-09-18T03:38:39.960" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="75" PostTypeId="1" AcceptedAnswerId="81" CreationDate="2014-04-16T01:17:26.477" Score="18" ViewCount="4526" Body="&lt;p&gt;What is the period of the thermohaline circulation in the ocean? Obviously, individual particles may take longer or shorter, but what is the average for a small water parcel to do a full loop and end up back in the same place?&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="192" LastEditDate="2014-10-10T01:42:05.183" LastActivityDate="2014-10-10T01:42:05.183" Title="How long does it take for the ocean conveyor to circulate?" Tags="|ocean|thermohaline-circulation|oceanography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="76" PostTypeId="1" AcceptedAnswerId="106" CreationDate="2014-04-16T01:20:11.593" Score="11" ViewCount="606" Body="&lt;p&gt;What parts of the fossil record are most lacking in specimens? That is, if you were to trace the evolution of a modern mammal (humans, for example) from abiogenesis to now, which periods are the most lacking in fossils? Where are the biggest gaps in our evolutionary history.&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2019-12-14T15:31:11.420" Title="What periods of the fossil record are most lacking in specimens?" Tags="|fossils|paleontology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="77" PostTypeId="2" ParentId="70" CreationDate="2014-04-16T01:21:10.163" Score="28" Body="&lt;p&gt;In the US, meteorologists forecast the probability of ANY amount of precipitation falling.  The minimum amount of that we deem acceptable to meet this criteria is .01&quot;.  So, we are forecasting the probability of one hundredth of an inch of precipitation to fall at a location.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We look at observational data from ground stations, satellites, and computer models and combine it with our knowledge of meteorology/climate and our past experiences with similar weather systems to create a probability of precipitation.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;A 10% chance of rain means that 10 times out of 100 with this weather pattern, we can expect at least .01&quot; at a given location.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Likewise, a 90% chance of rain would mean that 90 times out of 100 with this weather pattern, we can expect at least .01&quot; at a given location.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly, the Storm Prediction Center issues severe threat probabilities.   You can see things like 5% chance of tornado or 15% chance of severe hail.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This simply means 5 times out of 100 in this scenario we can expect a tornado.  Or 15 times out of 100 you can expect severe hail with thunderstorms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;By definition, there is no difference in the amount of rain forecast by a 10% chance or a 90% chance.  Instead, that information is defined elsewhere, typically by a Quantitative Precipitation Forecast (QPF).&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meteorologists are still struggling with the best ways to inform the public about the differences between high chance, low QPF events versus low chance, high QPF events, and everything else in between.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meteorologists are still human and have their own wet or dry biases that can hedge the chance of precipitation you see.   Recently, forecasts are relying more on bias-correction techniques and statistical models to remove the human bias from precipitation forecasts. &lt;/p&gt;&#xA;" OwnerUserId="38" LastEditorUserId="38" LastEditDate="2014-04-17T00:49:34.037" LastActivityDate="2014-04-17T00:49:34.037" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="78" PostTypeId="2" ParentId="73" CreationDate="2014-04-16T01:25:47.183" Score="18" Body="&lt;p&gt;The Short Answer is Yes. The consensus is that humans can prematurely trigger earthquakes, and this &lt;a href=&quot;http://articles.adsabs.harvard.edu//full/1986AREPS..14...21S/0000021.000.html&quot;&gt;paper in 1986's EPSL annual reviews&lt;/a&gt; seems to be in full support. &lt;a href=&quot;http://egsp.lyellcollection.org/content/5/1/405.short&quot;&gt;There is also this paper&lt;/a&gt; which suggests that mining induced earthquakes are quite common. &lt;a href=&quot;http://www.sciencemag.org/content/341/6142/1225942.short&quot;&gt;A third paper&lt;/a&gt; published in Science last year also suggests that hydraulic fracking can cause earthquakes. There are many more papers on this subject, easily found using google scholar, as it is contentious to both the public and scientists alike.&lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-04-16T01:25:47.183" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="79" PostTypeId="2" ParentId="73" CreationDate="2014-04-16T01:28:08.930" Score="26" Body="&lt;p&gt;Yep, mining can trigger earthquakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;http://www.scientificamerican.com/article/geothermal-drilling-earthquakes/&quot;&gt;a Scientific American article&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We've been monitoring [The Geysers] since 1975. All the earthquakes we see there are [human] induced. When they move production into a new area, earthquakes start there, and when they stop production, the earthquakes stop.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is talking about geothermal power. They create small little fractures, which cause tiny earthquakes. They then harness this power for electricity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earthquakes can also be caused by coal mining and other mining, according to &lt;a href=&quot;http://news.nationalgeographic.com/news/2007/01/070103-mine-quake.html&quot;&gt;this study&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Klose has identified more than 200 human-caused temblors, mostly in&#xA;  the past 60 years. &quot;They were rare before World War II,&quot; he said.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Most were caused by mining, he said, but nearly a third came from&#xA;  reservoir construction.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Oil and gas production can also trigger earthquakes, he added.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Three of the biggest human-caused earthquakes of all time, he pointed&#xA;  out, occurred in Uzbekistan's Gazli natural gas field between 1976 and&#xA;  1984 (map of Uzbekistan).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://unews.utah.edu/news_releases/u-seismologists-study-mining-induced-earthquakes/&quot;&gt;Another study&lt;/a&gt; also concluded this.&lt;/p&gt;&#xA;" OwnerUserId="20" LastActivityDate="2014-04-16T01:28:08.930" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="80" PostTypeId="2" ParentId="71" CreationDate="2014-04-16T01:45:05.267" Score="15" Body="&lt;p&gt;Challenger Deep (10.99km) in the Mariana's Trench is the deepest part of the ocean floor. This is probably close to the deepest theoretically possible ocean floor with the  current thermal regime.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With the current thermal regime, the deepest 'steady state' ocean floor depth is about 5.5-6km ( &lt;a href=&quot;http://www.auscope.org.au/userfiles/file/Communications/Muller_etal_age_rate_asym_G3_2008-1.pdf&quot; rel=&quot;nofollow&quot;&gt;cooling curves at Muller et al&lt;/a&gt; ) - limit is reached as the ocean crust cools and subsides. The crust (lithosphere) is effectively floating on the mantle (asthenosphere), and this steady state situation is known as 'isostatic equilibrium'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can get deeper by moving from a static to a dynamic situation. A subduction zone provides this - the subducting plate is moving and being pushed down, resulting in a deep ocean trench. Eg. The Mariana's, or the trench offshore Chile. A fast subduction zone should go deeper. A deep hole like this will also tend to fill with sediment. The fastest subduction zones move at about 16cm (and these are only the short arcs). The physical characteristics of the ocean crust will also vary a little (thickness, temperature), but beyond these parameters it is difficult to make the hole deeper, as it were.&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorUserId="44" LastEditDate="2014-04-16T12:37:49.057" LastActivityDate="2014-04-16T12:37:49.057" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="81" PostTypeId="2" ParentId="75" CreationDate="2014-04-16T01:53:47.517" Score="11" Body="&lt;p&gt;According to &lt;a href=&quot;http://oceanservice.noaa.gov/facts/conveyor.html&quot;&gt;NOAA&lt;/a&gt; It takes almost a 1000 years to complete a cycle. I am not sure how accurate, or where the citation came from their information so take it with a grain of salt. &lt;a href=&quot;http://eesc.columbia.edu/courses/ees/climate/lectures/o_circ.html&quot;&gt;Lecture notes&lt;/a&gt; from one of Columbia University's 2007 &quot;The Climate System&quot; class suggests this process takes between 100-1000 years. This &lt;a href=&quot;http://cdiac.ornl.gov/oceans/glodap/glodap_pdfs/Thermohaline.web.pdf&quot;&gt;paper&lt;/a&gt; says Thermohaline Circulation overturns deep water every 600 years or so.&lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-04-16T01:53:47.517" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="82" PostTypeId="2" ParentId="67" CreationDate="2014-04-16T01:54:41.523" Score="15" Body="&lt;p&gt;There are two types of dust storms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first, a dust storm or &quot;sandstorm&quot;, is associated with a synoptic scale feature (like a low pressure system).  Strong winds along air mass boundaries (i.e. cold front) create clouds of dust as sand, dust, or other particulates become suspended by turbulent eddies near the surface and aloft. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://acd.ucar.edu/~drews/sandstorm/index_html_166874ec.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/j94iy.jpg&quot; alt=&quot;Arabian dust storm&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second, the infamous &quot;haboob&quot; is associated with the cold pool of thunderstorms.  In the American desert southwest, during the summer monsoon, numerous thunderstorms develop. These thunderstorms produce rain or virga that cools the atmosphere beneath the thunderstorm as it evaporates.  Cool air sinks into what is known as a 'cold pool'. Cold pools generally strengthen as a thunderstorm decays.  Cold pools are air masses of cooler than environment air that spreads out like a pancake in all directions from beneath the thunderstorm.  These cold pools can create wind gust fronts between 40 and 70mph. Similar to larger dust storms, sand, dust or other particulates become suspended in the air and create the wall of dust.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.islandnet.com/~see/weather/graphics/photos0910/gustfront1.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HmSgd.jpg&quot; alt=&quot;cold pool&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="38" LastEditorUserId="67" LastEditDate="2014-05-29T20:08:36.223" LastActivityDate="2014-05-29T20:08:36.223" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="83" PostTypeId="2" ParentId="7" CreationDate="2014-04-16T02:30:49.943" Score="16" Body="&lt;p&gt;Here is an estimate from Beauchamp and Baud (2002), for parts of the ocean around Pangea, for the latter parts of it's existence (~300-250mya). It is based on various previous papers that looked at deposits of carbonates and phosphate deposits, and made a few assumptions, including a sufficient supply of silica and nutrient inputs, and environments suitable for particular biota, including particularly siliceous sponges:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/BbzqN.jpg&quot; alt=&quot;Ocean circulation patterns for &quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Beauchamp, B. &amp;amp; Baud, A., 2002. Growth and demise of Permian biogenic chert along northwest Pangea: evidence for end-Permian collapse of thermohaline circulation. Palaeogeography, Palaeoclimatology, Palaeoecology, 184(1–2), pp.37–63. &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0031018202002456&quot; rel=&quot;noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/S0031018202002456&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="56" LastActivityDate="2014-04-16T02:30:49.943" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="84" PostTypeId="2" ParentId="71" CreationDate="2014-04-16T03:59:28.373" Score="6" Body="&lt;p&gt;In theory, a new fissure could open up at any time, leading to a new depth. But for a long while now, the deepest known natural point is the &lt;a href=&quot;http://en.wikipedia.org/wiki/Mariana_Trench&quot;&gt;Mariana Trench&lt;/a&gt; - just shy of 11km deep!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, we have gone deeper!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In 1970, the &lt;a href=&quot;http://en.wikipedia.org/wiki/Kola_Superdeep_Borehole&quot;&gt;Kola Superdeep Bore&lt;/a&gt; project had several boreholes drilled from a central hole. The deepest - SG-3, reached 12,262metres into the earth.  The goal was to get to 15000m, but the problem is that the drill bits start melting in the heat down there - they need to operate in over 300 degrees Celsius!&lt;/p&gt;&#xA;" OwnerUserId="73" LastActivityDate="2014-04-16T03:59:28.373" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="85" PostTypeId="1" AcceptedAnswerId="231" CreationDate="2014-04-16T04:00:51.570" Score="22" ViewCount="442" Body="&lt;p&gt;Post Christchurch-2011 earthquake, there was much concern that fracking in the surrounding areas might lead to further quakes, as was rumoured to have happened elsewhere in the world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there evidence that fundamentally validates or discredits this?&lt;/p&gt;&#xA;" OwnerUserId="73" LastEditorDisplayName="user12525" LastEditDate="2019-04-19T09:29:31.900" LastActivityDate="2019-04-19T09:29:31.900" Title="Is fracking likely to produce earthquakes?" Tags="|geology|geophysics|earthquakes|seismology|fracking|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="86" PostTypeId="1" AcceptedAnswerId="215" CreationDate="2014-04-16T04:13:41.970" Score="15" ViewCount="120548" Body="&lt;p&gt;It seems to be a fairly widely held belief that if the sky is green or yellow, a tornado may be developing/approaching. But is there any truth to it? Could the color of the sky actually be associated with the hail that usually accompanies a tornado?&lt;/p&gt;&#xA;" OwnerUserId="58" LastActivityDate="2017-08-09T02:04:45.253" Title="Does a green or yellow sky actually indicate a tornado?" Tags="|weather|storms|tornado|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="87" PostTypeId="2" ParentId="51" CreationDate="2014-04-16T04:32:27.333" Score="6" Body="&lt;p&gt;I looked into this and found &lt;a href=&quot;http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.69.6406&amp;amp;rep=rep1&amp;amp;type=pdf&quot; rel=&quot;nofollow&quot;&gt;Sublimation from a seasonal snowpack at a continental, mid-latitude apline site&lt;/a&gt; by Eran Hood, Mark Williams, and Don Cline go into great detail on this subject. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Martinelli (1960) reports that sublimation is&#xA;responsible for only 1-2% of summer snowpack ablation in snowfields between 3500-3800 m in the Rocky&#xA;Mountains.&lt;/li&gt;&#xA;&lt;li&gt;(West and Knoerr, 1959) Measurements from snow evaporation pans at the Central Sierra Snow Laboratory in&#xA;California measured annual sublimation at only 25-35 mm or 2-3% of total ablation over the snow season&lt;/li&gt;&#xA;&lt;li&gt;Beaty (1975) reported that sublimation was responsible for 80%&#xA;of the ablation of fresh snow and 60% of the ablation of older snow during springtime conditions in the&#xA;White Mountains of California.&lt;/li&gt;&#xA;&lt;li&gt;Kattelmann and Elder&#xA;(1991) estimated sublimation from snow to be 18% of total precipitation over two water years based on data&#xA;collected in the Emerald Lake Basin in the Sierra Nevada.&lt;/li&gt;&#xA;&lt;li&gt;Marks and Dozier snowpack estimated lost to sublimation in the Sierra Nevada to be&#xA;20%. &lt;/li&gt;&#xA;&lt;li&gt;Water losses to sublimation were equal to 13% of annual&#xA;precipitation at Niwot Ridge.&lt;/li&gt;&#xA;&lt;li&gt;Hood, Willians &amp;amp; Cline report 15% of maximum snow accumulation at the study site was lost due to sublimation.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/%28SICI%291099-1085%28199812%2912:15%3C2317%3a%3aAID-HYP799%3E3.0.CO;2-X/abstract&quot; rel=&quot;nofollow&quot;&gt;Another article&lt;/a&gt; notes the importance of vegetation on sublimation:   ranging from 13% for a mixed spruce–aspen, 31% for the mature pine and 40% for a mature spruce stand. The results indicate that sublimation can be a significant abstraction of water from mature evergreen stands in northern forests.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The results seem somewhat inconclusive.  This topic needs more comprehensive and robust research.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Take-aways&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;15-20% is the range given by the most recent studies in the intermountain USA.&lt;/strong&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Solar&#xA;radiation was the most closely correlated with trends in sublimation and condensation.&lt;/strong&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Vegetation impacts sublimation rates.&lt;/strong&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="38" LastEditorUserId="38" LastEditDate="2014-04-17T23:47:45.370" LastActivityDate="2014-04-17T23:47:45.370" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="88" PostTypeId="1" AcceptedAnswerId="91" CreationDate="2014-04-16T05:12:33.473" Score="47" ViewCount="32752" Body="&lt;p&gt;According to textbook knowledge, the mass of the earth is about &lt;span class=&quot;math-container&quot;&gt;$6 × 10^{24}\,\mathrm{kg}$&lt;/span&gt;.  How is this number determined when one cannot just weight the earth using regular scales?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorDisplayName="user20559" LastEditDate="2021-09-03T13:35:15.127" LastActivityDate="2022-05-08T17:13:38.817" Title="How is the mass of the Earth determined?" Tags="|geophysics|geology|" AnswerCount="5" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="89" PostTypeId="2" ParentId="88" CreationDate="2014-04-16T05:35:36.323" Score="21" Body="&lt;p&gt;The mass of the Earth can be determined by the so called &lt;a href=&quot;https://en.wikipedia.org/wiki/Cavendish_experiment&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cavendish experiment&lt;/a&gt;. Henry Cavendish used an apparatus to determine the gravitational constant G which appears in the full equation for the gravitational force:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ F = {Gm_1m_2\over R^2} $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$m_1$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$m_2$&lt;/span&gt; are the masses of two objects, &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; the distance between the centers of gravity of the objects and &lt;span class=&quot;math-container&quot;&gt;$G$&lt;/span&gt; the gravitational constant (approximately &lt;span class=&quot;math-container&quot;&gt;$6.674 \times 10^{-11} \mathrm{N~m^2~kg^{-2}}$&lt;/span&gt;).&lt;/p&gt;&#xA;&lt;p&gt;As the diameter of the earth is known, as well as the gravitational constant, determining the gravitational force on an object with known mass gives us the mass of the object exerting that force (so the Earth).&lt;/p&gt;&#xA;" OwnerUserId="79" LastEditorUserId="2470" LastEditDate="2022-05-08T17:13:38.817" LastActivityDate="2022-05-08T17:13:38.817" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="90" PostTypeId="1" AcceptedAnswerId="107" CreationDate="2014-04-16T05:35:47.763" Score="1" ViewCount="698" Body="&lt;p&gt;What are some good textbooks and online resources for learning about geophysics? That is, physics, as it relates to the earth's geology, shape, and internal structure.&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="42" LastEditDate="2014-04-21T01:50:33.773" LastActivityDate="2014-04-21T01:50:33.773" Title="What are some good resources to learn about geophysics?" Tags="|geophysics|resources|" AnswerCount="3" CommentCount="7" ClosedDate="2014-04-16T14:45:58.580" ContentLicense="CC BY-SA 3.0" />
  <row Id="91" PostTypeId="2" ParentId="88" CreationDate="2014-04-16T05:36:45.187" Score="44" Body="&lt;p&gt;According to &lt;strong&gt;Newton's Law of Gravity&lt;/strong&gt; based on attractive force (gravitational force) that two masses exert on each other:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$F=\frac{GmM}{r^2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$F$&lt;/span&gt; is the gravitational force&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$G = 6.67 \times 10^{-11}\ \mathrm{m}^3\ \mathrm{kg}^{-1}\ \mathrm{s}^{-2}$&lt;/span&gt; is a constant of proportionality&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$M$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt; are the two masses exerting the forces&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; is the distance between the two centers of mass.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;From &lt;strong&gt;Newton's second law of motion&lt;/strong&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$F=ma$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$F$&lt;/span&gt; is the force applied to an object&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt; is the mass of the object&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$a$&lt;/span&gt; is its acceleration due to the force.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;Equating both the equations&lt;/strong&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$F = \frac{GmM}{r^2} = ma$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{GM}{r^2}= a$$&lt;/span&gt; (The &lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt;'s canceled out.)&lt;/p&gt;&#xA;&lt;p&gt;Now solve for &lt;span class=&quot;math-container&quot;&gt;$M$&lt;/span&gt;, the mass of the Earth.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$M = \frac{ar^2}{G}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where &lt;span class=&quot;math-container&quot;&gt;$a = 9.8\ \mathrm{m}\ \mathrm{s}^{-2}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$r = 6.4 \times 10^6\ \mathrm{m}$&lt;/span&gt;, and &lt;span class=&quot;math-container&quot;&gt;$G = 6.67 \times 10^{-11}\ \mathrm{m}^3\ \mathrm{kg}^{-1}\ \mathrm{s}^{-2}$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$M = 9.8 \times (6.4 \times 10^6)^2/(6.67 \times 10^{-11})\ \mathrm{kg}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Hence,&lt;/p&gt;&#xA;&lt;h2&gt;&lt;span class=&quot;math-container&quot;&gt;$M = 6.0 \times 10^{24}\ \mathrm{kg}$&lt;/span&gt;&lt;/h2&gt;&#xA;" OwnerUserId="78" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-12-01T06:27:26.867" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="92" PostTypeId="2" ParentId="88" CreationDate="2014-04-16T05:37:38.580" Score="11" Body="&lt;p&gt;The easiest way is to use a gravimeter from a satellite, and solve the famous inverse square law equation that Newton came up with centuries ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another way, which might be a worthwhile exercise ( I had to do it in a Solid-Earth Geophysics Class) is to assume a 4 layered earth (crust,mantle, outer core, inner core). Use seismic data to not only get the depths of each layer (through S/P reflections) but also the densities of each layer through seismic velocities. You can assume homogenous densities for each &quot;shell&quot; and find the mass using the circumference of the earth (and thus diameter).    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can also solve it using kepler/newton laws of planetary motion, if you know the distance between two bodies (Earth and moon / Earth and Sun).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;IE, there are many ways in which Newton's law of gravity gives us a very good approximation for the Earth's mass.  &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-04-16T05:37:38.580" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="93" PostTypeId="2" ParentId="90" CreationDate="2014-04-16T05:47:37.517" Score="7" Body="&lt;p&gt;There are two universally loved geophysics texts : &lt;a href=&quot;http://books.google.com/books/about/Geodynamics.html?id=-nCHlVuJ4FoC&quot;&gt;Turcotte and Shubert&lt;/a&gt;  and &lt;a href=&quot;http://epsc.wustl.edu/seismology/book/&quot;&gt;Stein and Wyessesion&lt;/a&gt;. Both are upper division/lower graduate level texts. &lt;a href=&quot;http://books.google.com/books/about/The_Solid_Earth.html?id=PifkAotvTroC&quot;&gt;Fowler&lt;/a&gt; is great if you do not have a strong mathematical background (multivariate calculus). Beyond that, it might be difficult to get a a good understanding without an Introductory physics course, and a few semesters of calculus. A good way to learn about geophysics, is in fact, just learning about physics and mathematics in general. Hopefully this stack exchange will also become a good resource. &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-04-16T05:47:37.517" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="94" PostTypeId="1" AcceptedAnswerId="97" CreationDate="2014-04-16T05:48:08.913" Score="16" ViewCount="10148" Body="&lt;p&gt;I have heard that the Earth is made up of four layers, being the crust, the mantle, the outer core and the inner core.  I have also heard that the Earth's temperature increases as you move from the crust to the inner core, with the inner core having a temperature of 4700 degrees.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is it that the inside of the Earth is so hot compared to the outside of the Earth?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="6129" LastEditDate="2020-05-07T11:28:42.073" LastActivityDate="2020-05-07T11:28:42.073" Title="Why is the inside of the Earth so hot?" Tags="|geophysics|temperature|geothermal-heat|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="95" PostTypeId="2" ParentId="60" CreationDate="2014-04-16T05:53:17.617" Score="13" Body="&lt;p&gt;Essentially, we can't. At a meeting some years ago, different specialists tried to define the onset of glaciation and found that each (sub-) discpline had their own definition. An oceanographer boldly stated the glaciation started 2000 years ago since a change in the Greenland ocean currents occurred at that time which was observed to also change before the latest glaciation. But, since we are unable to predict natural variations with any certainty (at least useful for any human lifetime) such observations remain speculation and ideas worthy of more research. Milankovich theory predicts an ice age but the onset will likely be very weak for us to detect in the general noise and human interference with the system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition, we must remember that and ice age is not a sudden event (as seen in the movies) and is likely to start with a slow general drop in temperature with superimposed oscillations (both colder and warmer), at least if our understanding of past ice ages is anything to go by. Hence, we will not know, other than in hindsight, and by some definition, when such a time started.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, our understanding says we should be heading towards a colder period but how we enter into it, for example, given our influence of the climate system makes it difficult to predict.&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2014-04-16T05:53:17.617" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="96" PostTypeId="1" AcceptedAnswerId="153" CreationDate="2014-04-16T05:55:55.730" Score="35" ViewCount="10680" Body="&lt;p&gt;Earth is the only planet in our solar system that has copious amounts of water on it.  Where did this water come from and why is there so much water on Earth compared to every other planet in the solar system?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorDisplayName="user12525" LastEditDate="2019-04-16T09:23:28.800" LastActivityDate="2019-07-22T11:34:39.507" Title="How and why did the oceans form on Earth but not on other planets?" Tags="|geology|oceanography|geochemistry|planetary-science|" AnswerCount="5" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="97" PostTypeId="2" ParentId="94" CreationDate="2014-04-16T05:58:50.457" Score="13" Body="&lt;p&gt;This is a very good question. There a few main heat sources: Heat(and work) left over from the formation of the earth, work (potential energy) generated by dense iron sinking into the center of the earth and forming a core, and radioactive energy. Since the Thermal diffusivity of the materials that make up the earth is low, heat transport is very slow and thus the planet retains a significant amount of its heat. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another reason why the earth is so hot, is that mantle convection is a very inefficient way to transport said heat, and thus the earth loses energy very slowly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We know how hot the interior of the earth might be because of laboratory experiments, and also volcanic eruptions. How much energy(temperature) does it take to melt gabbro (mantle rock)? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Interestingly enough, the earth is cooling. And the inner core / outer core boundary is a freezing front (meaning turning from a liquid outer core to a solid inner core). Though, it is a very hot freezing front.&lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="32" LastEditDate="2014-05-03T22:42:40.900" LastActivityDate="2014-05-03T22:42:40.900" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="98" PostTypeId="2" ParentId="38" CreationDate="2014-04-16T06:10:14.857" Score="8" Body="&lt;p&gt;There is no direct answer. One way to think about this is to consider the water cycle. Water evaporates from the oceans and is precipitates over land. Distance from the ocean affects the amount of precipitation so at the center of a large contintent you may have less precipitation than over a smaller one. Mountains also drain moisture out of the air as it is heaved. hence the topography of the continents affect this effect. A Pangea directly after collisions will likely have more and higher mountains than a later stage when break-up is imminent. Location on the earth's surface is a third factor since we have larger scale circulation belts that affect the atmospheric conditions so that we have a tropical belt (the Intertropical Convergence Zone) around the equator, a drier zone north and south of the ITCZ, followed by temperate and polar zones towards the poles. Hence the location of the continent(s) and their topography will affect the zones and the zones will will determine which parts receive more or less precipitation. Furthermore the movement of the continent(s) through these climate zones change conditions as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In summary, we can be sure it is not constant over geological times. The only possible way to get some relative handle on the question would be to try to apply a global circulation model to past continent configurations, including topographical effects and see what comes out, being aware of all uncertainties and comparing with geological evidence.&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2014-04-16T06:10:14.857" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="99" PostTypeId="1" AcceptedAnswerId="100" CreationDate="2014-04-16T06:15:52.470" Score="17" ViewCount="2249" Body="&lt;p&gt;A compass can tell me the directions of the Earth's North and South poles?  What is it about the Earth that produces this &quot;polarity&quot; such that a compass can pick it up?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first thing that jumped into my head was the Earth's rotation, but if that is the explanation, why have I heard from people that the Earth's polarity can switch every million years or so?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/8VhZa.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="94" LastEditDate="2014-06-07T07:08:49.050" LastActivityDate="2014-06-07T07:08:49.050" Title="What causes the Earth to have magnetic poles?" Tags="|geophysics|geomagnetism|paleomagnetism|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="100" PostTypeId="2" ParentId="99" CreationDate="2014-04-16T06:20:21.927" Score="23" Body="&lt;p&gt;Well, firstly it's important to recognise that the poles are merely the extremities of the shape of a magnetic field - the earth's magnetic field.  All magnetic fields have polarities as such.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, you're asking why the field itself even exists, I gather.  In this case it's generated by electric currents in the conductive molten iron (and other metals) in the core of the earth, as a result of convection currents generated by escaping heat.   This is known as a geodynamo, and is one way of generating a magnetic field.  However, exactly why this occurs is still under investigation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More is available in this &lt;a href=&quot;http://en.wikipedia.org/wiki/Earth%27s_magnetic_field#Physical_origin&quot;&gt;Wiki piece - specifically on the physical origins of the earth's magnetic field&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="73" LastEditorUserId="99" LastEditDate="2014-04-16T14:10:32.443" LastActivityDate="2014-04-16T14:10:32.443" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="101" PostTypeId="1" AcceptedAnswerId="119" CreationDate="2014-04-16T06:35:28.227" Score="15" ViewCount="676" Body="&lt;p&gt;I have heard that geothermal heating is a way of generating energy from the temperature difference between the inner layers of the Earth and the Earth's crust.  How is it possible to extract this energy?  Must one be near a tectonic plate boundary to gain access to this temperature gradient?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="725" LastEditDate="2016-01-22T00:56:45.633" LastActivityDate="2020-05-06T07:52:42.797" Title="How does geothermal heating work?" Tags="|geophysics|geothermal-heat|drilling|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="102" PostTypeId="1" AcceptedAnswerId="117" CreationDate="2014-04-16T06:37:16.277" Score="17" ViewCount="3950" Body="&lt;p&gt;Are there any estimates of the amount of Uranium there is in Earth's Crust? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From what I know, it's supposed that there are large amounts of Uranium in Earth's Core, the decay of which is responsible for the core maintaining its high temperature. Mining the core is hardly imaginable, while the resources in Crust are more accessible available for mining: so how much is in the Crust, and at what levels of concentration? (which affects the viability of accessing it).&lt;/p&gt;&#xA;" OwnerUserId="77" LastEditorUserId="23" LastEditDate="2014-04-16T15:17:06.677" LastActivityDate="2019-02-11T07:21:24.743" Title="How much Uranium is there in the Earth's Crust?" Tags="|resources|uranium|geochemistry|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="103" PostTypeId="1" AcceptedAnswerId="116" CreationDate="2014-04-16T06:46:49.337" Score="19" ViewCount="762" Body="&lt;p&gt;I have heard from many people that sinks do not empty in a particular pattern depending on what hemisphere you are in, but I have also heard from people who adamant that a sink of water would empty clockwise in one hemisphere and anti-clockwise in another.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While I acknowledge the above idea is probably a myth, is there any simple experiment that one can do do determine what hemisphere they are in, utilizing the Coriolis effect, or otherwise?&lt;/p&gt;&#xA;" OwnerUserId="51" LastActivityDate="2014-11-12T15:03:22.197" Title="Is there any simple way of using the Coriolis effect to determine what hemisphere you are in?" Tags="|coriolis|" AnswerCount="4" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="104" PostTypeId="1" CreationDate="2014-04-16T06:50:12.873" Score="13" ViewCount="1309" Body="&lt;p&gt;Is there any standard internationally recognizable definition of the term &quot;mountain&quot;? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If international texts describe some terrain as mountains, do they use some international definition of the term, or do they use the local definitions?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, in Poland geographers usually agree that terrain is called mountains when its peaks are at least 600 meters above sea level. This makes, for example, the Świętokrzyskie Mountains 'mountains', although only a single peak is above 600m. But there are other definitions that are bases on the geological structure of the terrain, not on the height.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Germans, from what I know, use a definition based on 'Reliefenergie', so the relative height difference for every square kilometer, independent of the absolute height.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What criteria are usually used to call a terrain 'mountains' in international community? For example, what would we use on this site?&lt;/p&gt;&#xA;" OwnerUserId="77" LastEditorUserId="56" LastEditDate="2014-04-16T08:20:14.513" LastActivityDate="2014-04-20T07:38:18.073" Title="Is there a standard definition of the term &quot;mountain&quot;?" Tags="|mountains|geography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="105" PostTypeId="1" AcceptedAnswerId="164" CreationDate="2014-04-16T07:01:18.227" Score="13" ViewCount="935" Body="&lt;p&gt;What is the scientific reason for the majestic sights of the northern and southern lights, otherwise known as Auroras near the magnetic poles, and why do the northern lights differ from the southern lights?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/9mVih.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="51" LastEditDate="2014-04-16T07:07:52.837" LastActivityDate="2014-04-16T16:43:32.057" Title="What causes the beautiful Auroras on the north and south magnetic poles?" Tags="|auroras|" AnswerCount="2" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="106" PostTypeId="2" ParentId="76" CreationDate="2014-04-16T07:23:17.630" Score="14" Body="&lt;p&gt;The biggest temporal gap would be (IMO) the Precambrian, specifically pre-Ediacarian. Accordingly the biggest gap in the evolutionary history is the origin of eukaryots, both because of the paucity of pre-Ediacarian formations but also because few of the early protists were likely to be fossilizable.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the probable apparition of life ca. 3.8-3.5 Ga (e. g. &lt;strong&gt;1&lt;/strong&gt; for a review of Archean fossils) to the Ediacarian (ca. 600 Ma) in which metazoans (i. e. &quot;animals&quot;) are already diverse (e. g. &lt;strong&gt;2&lt;/strong&gt;), this is more than 3 Ga of life history for which we have very little fossils (though our knowledge of this fossil record increases currently thanks, in part, to our better understanding of the &quot;chemical&quot; fossil record).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;1&lt;/strong&gt;: J. W. Schopf, 2006. &lt;a href=&quot;http://rstb.royalsocietypublishing.org/content/361/1470/869&quot;&gt;Fossil evidence of Archaean life.&lt;/a&gt; Philosophical transactions of the Royal Society, B., 361: 869-885.&lt;br&gt;&#xA;&lt;strong&gt;2&lt;/strong&gt;: S.Conway Morris, 1993. &lt;a href=&quot;http://www.nature.com/nature/journal/v361/n6409/abs/361219a0.html&quot;&gt;The fossil record and the early evolution of the Metazoa&lt;/a&gt;. Nature, 361: 219-225.&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-04-16T07:46:33.863" LastActivityDate="2014-04-16T07:46:33.863" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="107" PostTypeId="2" ParentId="90" CreationDate="2014-04-16T07:34:37.237" Score="5" Body="&lt;p&gt;I also strongly suggest the courses available on the coursera platform under the category &quot;Energy &amp;amp; Earth Sciences&quot; &lt;a href=&quot;https://www.coursera.org/courses?orderby=upcoming&amp;amp;cats=energy&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="9" LastActivityDate="2014-04-16T07:34:37.237" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="108" PostTypeId="1" AcceptedAnswerId="110" CreationDate="2014-04-16T07:35:26.960" Score="17" ViewCount="12441" Body="&lt;p&gt;We've all learned at school that the Earth was a sphere. Actually, it is more nearly a slightly flattened sphere - an oblate ellipsoid of revolution, also called an oblate spheroid. This is an ellipse rotated about its shorter axis.  What are the physical reasons for that phenomenon?&lt;/p&gt;&#xA;" OwnerUserId="91" LastEditorUserId="6031" LastEditDate="2020-07-14T00:49:49.590" LastActivityDate="2020-07-14T00:49:49.590" Title="Why is Earth not a sphere?" Tags="|geodesy|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="109" PostTypeId="2" ParentId="72" CreationDate="2014-04-16T07:42:07.570" Score="28" Body="&lt;p&gt;Firstly it is worth demonstrating that 97% of climate scientists agree that climate-warming trends over the past century are very likely due to human activities.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;W. R. L. Anderegg, “Expert Credibility in Climate Change,” Proceedings&#xA;  of the National Academy of Sciences Vol. 107 No. 27, 12107-12109 (21&#xA;  June 2010); DOI: 10.1073/pnas.1003187107.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;P. T. Doran &amp;amp; M. K. Zimmerman, &quot;Examining the Scientific Consensus on&#xA;  Climate Change,&quot; Eos Transactions American Geophysical Union Vol. 90&#xA;  Issue 3 (2009), 22; DOI: 10.1029/2009EO030002.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;N. Oreskes, “Beyond the Ivory Tower: The Scientific Consensus on&#xA;  Climate Change,” Science Vol. 306 no. 5702, p. 1686 (3 December 2004);&#xA;  DOI: 10.1126/science.1103618.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But what percentage of the increase is attributed to humans?  Probably almost of all of it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The scientist Gavin Schmidt from NASA was asked this question on &lt;a href=&quot;http://www.realclimate.org/?comments_popup=1853#comment-142358&quot; rel=&quot;noreferrer&quot;&gt;realclimate.org&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;His response was as follows:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Over the last 40 or so years, natural drivers would have caused&#xA;  cooling, and so the warming there has been (and some) is caused by a&#xA;  combination of human drivers and some degree of internal variability.&#xA;  I would judge the maximum amplitude of the internal variability to be&#xA;  roughly 0.1 deg C over that time period, and so given the warming of&#xA;  ~0.5 deg C, I'd say &lt;strong&gt;somewhere between 80 to 120% of the warming.&lt;/strong&gt;&#xA;  Slightly larger range if you want a large range for the internal&#xA;  stuff. &lt;em&gt;[emphasis added]&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The rapid increase in the human-driven component of the forcing are increasingly dwarfing the small, slow natural forcings, rendering them increasingly irrelevant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/epPSa.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="56" LastEditDate="2014-05-01T02:52:14.460" LastActivityDate="2014-05-01T02:52:14.460" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="110" PostTypeId="2" ParentId="108" CreationDate="2014-04-16T08:01:26.450" Score="24" Body="&lt;p&gt;Normally in the absence of rotation, the natural tenancy of gravity is to pull the Earth together in the shape of a sphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However the Earth in fact bulges at the equator, and the diameter across the equatorial plane is 42.72 km more than the diameter from pole to pole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is due to the rotation of the Earth.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/707k9.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As we can see in the image above, the spinning disk appears to bulge at the points on the disk furthest from the axis of rotation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is because in order for the particles of the disk to remain in orbit, there must be an inward force, known as the centripetal force, given by:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$F = \frac{mv^2}{r},$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $F$ is the force, $m$ is the mass of rotating body, $v$ is the velocity and $r$ is the radius of particle from the axis of rotation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the disk is rotating at a given angular velocity, say $\omega$, then the tangential velocity $v$, is given by $v = \omega r$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$F = m\omega^2r$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore the greater the radius of the particle, the more force is required to maintain such an orbit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore particles on the Earth near the equator, which are farthest from the axis of rotation, will buldge outwards because they require a greater inward force to maintain their orbit.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Additional details for more mathematically literate now that mathjax is enabled:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The net force on an object rotating around the equator with a radius $r$ around a planet with a gravitational force of $\frac{Gm_1m_2}{r^2}$ is the centripetal force given by,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$F_{net} = \frac{Gm_1m_2}{r^2} - N = m\omega^2r,$$ where $N$ is the normal force.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Re-arranging the above equation gives:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$N = \frac{Gm_1m_2}{r^2} - m\omega^2r$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The normal force here is the perceived downward force that a rotating body observers.  The equation shows that the perceived downward force is lessened due to the centripetal motion.  The typical example to illustrate this is there is an appearance of 0 gravity in a satellite orbiting the Earth, because in this situation the centripetal force is exactly balanced by the gravitational force.  On Earth however, the centripetal force is much less than the gravitational force, so we perceive almost the whole contribution of $mg$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now we will examine how the perceived gravitational force differs at different angles of latitude.  Let $\theta$ represent the angle of latitude.  Let $F_G$ be the force of gravity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In vector notation we will take the $j$-direction to be parallel with the axis of rotation and the $i$-direction to be perpendicular with the axis of rotation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the absence of the Earth's rotation,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$F_G = N = (-\frac{Gm_1m_2}{r^2}\cos\theta)\tilde{i} + (-\frac{Gm_1m_2}{r^2}\sin\theta)\tilde{j}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is easily seen that the above equation represents the perceived force of gravity in the absence of rotation.  Now the centripetal force acts only in the i-direction, since it acts perpendicular to the axis of rotation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we let $R_{rot}$ be the radius of rotation, then the centripetal force is $m_1\omega^2R_{rot}$, which for an angle of latitude of $\theta$ corresponds to $m_1\omega^2r\cos{\theta}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$N = (-\frac{Gm_1m_2}{r^2} + m_1\omega^2r)\cos{\theta}\tilde{i} + (-\frac{Gm_1m_2}{r^2})\sin{\theta}\tilde{j}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By comparing this equation to the case shown earlier in the absence of rotation, it is apparent that as $\theta$ is increased (angle of latitude), the effect of rotation on perceived gravity becomes negligible, since the only difference lies in the $x$-component and $\cos\theta$ approaches 0 as $\theta$ approaches 90 degrees latitude.  However it can also be seen that as theta approaches 0, near the equator, the $x$-component of gravity is reduced as a result of the Earth's rotation.  &lt;strong&gt;Therefore, we can see that the magnitude of $N$ is slightly less at the equator than at the poles.&lt;/strong&gt;  The reduced apparent gravitational pull here is what gives rise to the slight bulging of the Earth at the equator, given that the Earth was not originally as rigid as it is today (see other answer).&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="5510" LastEditDate="2016-04-29T20:59:36.513" LastActivityDate="2016-04-29T20:59:36.513" CommentCount="17" ContentLicense="CC BY-SA 3.0" />
  <row Id="111" PostTypeId="2" ParentId="103" CreationDate="2014-04-16T08:45:56.633" Score="14" Body="&lt;p&gt;It's my understanding that the famous &quot;sink swirl&quot; example doesn't work simply because the Coriolis effect is too weak at that scale: it's insignificant compared to the motion of the water from residual momentum from when it entered the sink, and from vibration, air motion, and so on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For long-range artillery, the Coriolis effect &lt;em&gt;can&lt;/em&gt; become noticeable: it causes the projectile to deviate from the path that you would otherwise expect it to follow. The most famous example is probably the &lt;a href=&quot;http://en.wikipedia.org/wiki/Paris_Gun#Use_in_World_War_I&quot;&gt;Paris gun&lt;/a&gt;. This probably doesn't constitute a practical experiment for most people, though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To address the &quot;or otherwise&quot; part of your question, there are definitely simpler ways to determine your hemisphere: if the sun is to the south in the middle of the day, you're in the northern hemisphere, and vice versa. This assumes that you know where north is, but you can determine this by observing the stars. (This, of course, requires a clear and visible sky.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have a way of measuring the vertical component of the Earth's magnetic field, you can also use the &lt;a href=&quot;http://en.wikipedia.org/wiki/Magnetic_dip&quot;&gt;magnetic dip&lt;/a&gt; to determine your hemisphere. This won't work well if you're less than about 15° from the equator, since the magnetic equator doesn't correspond exactly to the geographical equator.&lt;/p&gt;&#xA;" OwnerUserId="94" LastActivityDate="2014-04-16T08:45:56.633" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="112" PostTypeId="2" ParentId="104" CreationDate="2014-04-16T08:47:40.543" Score="12" Body="&lt;p&gt;There does not appear to be an agreed international definition of a mountain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the UK there is a colloquial definition that a mountain must be &quot;a thousand feet high&quot;. This definition is sufficiently firmly established in a &quot;folklore&quot; sense that the 1995 film &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/The_Englishman_Who_Went_Up_a_Hill_But_Came_Down_a_Mountain&quot; rel=&quot;noreferrer&quot;&gt;The Englishman Who Went Up a Hill But Came Down a Mountain&lt;/a&gt;&quot; centred around it for its plot, and this plot is allegedly based on an older story in the region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the UK's Ordnance Survey,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;There is no precise international definition of a mountain... However,&#xA;  it is generally agreed that the minimum height is 610 metres (2 000&#xA;  feet). (&lt;a href=&quot;http://mapzone.ordnancesurvey.co.uk/mapzone/didyouknow/whatis/q_12_70.html&quot; rel=&quot;noreferrer&quot;&gt;Source&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This definition does not make clear whether a 2000' rise from the surroundings is required, or whether a peak must simply be 2000' above sea level.&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2014-04-20T07:38:18.073" LastActivityDate="2014-04-20T07:38:18.073" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="113" PostTypeId="1" AcceptedAnswerId="129" CreationDate="2014-04-16T08:54:33.023" Score="19" ViewCount="3382" Body="&lt;p&gt;Tsunamis, in the deep ocean, &lt;a href=&quot;https://en.wikipedia.org/wiki/Tsunami#Characteristics&quot;&gt;travel at around 800 kilometers per hour&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The speed of sound under water is about 5300 kilometers per hour.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both of these waves are pressure waves, operating in the same medium. Why is one so much faster than the other?&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2020-07-05T10:39:12.220" Title="Why do Tsunamis travel slower than sound?" Tags="|tsunami|waves|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="114" PostTypeId="1" AcceptedAnswerId="223" CreationDate="2014-04-16T09:36:32.093" Score="20" ViewCount="1012" Body="&lt;p&gt;I have always wondered what is the origin of Montmartre mountain in Paris. What surprises me is that the whole area seems quite flat, and yet there's a very steep hill in the middle. How has that happen? Is it an instance of some common geological phenomenon?&lt;/p&gt;&#xA;" OwnerUserId="99" LastEditorUserId="73" LastEditDate="2014-04-17T11:22:24.667" LastActivityDate="2014-04-17T11:22:24.667" Title="What is the origin of the Montmartre mountain in Paris?" Tags="|geology|mountains|geomorphology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="115" PostTypeId="1" CreationDate="2014-04-16T09:41:37.597" Score="12" ViewCount="773" Body="&lt;p&gt;I have found on &lt;a href=&quot;http://en.wikipedia.org/wiki/Magnetic_hill&quot;&gt;Wikipedia&lt;/a&gt; that the term &quot;magnetic hill&quot; is used for an optical illusion. However, I have heard that there are true &lt;em&gt;magnetic hills&lt;/em&gt;, i.e., locations where you can't use compass simply because the nearby hill generates its own magnetic field, which drives your compass crazy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a list of such places, so that one can visit any of them? (I'm especially interested in places in Europe.)&lt;/p&gt;&#xA;" OwnerUserId="99" LastEditorUserId="44" LastEditDate="2014-04-16T13:05:10.447" LastActivityDate="2014-04-19T09:04:49.703" Title="Magnetic &quot;magnetic hills&quot;?" Tags="|mountains|geomagnetism|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="116" PostTypeId="2" ParentId="103" CreationDate="2014-04-16T10:02:33.900" Score="23" Body="&lt;p&gt;You can use the &lt;a href=&quot;http://en.wikipedia.org/wiki/Foucault_pendulum&quot;&gt;Foucault pendulum&lt;/a&gt; to determine the hemisphere: Its plane of movement rotates:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;anti-clockwise in the southern hemisphere;&lt;/li&gt;&#xA;&lt;li&gt;clockwise in the northern hemisphere. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The rotation of the plane can be explained by the Coriolis force.&lt;/p&gt;&#xA;" OwnerUserId="99" LastEditorUserId="99" LastEditDate="2014-04-16T14:39:39.970" LastActivityDate="2014-04-16T14:39:39.970" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="117" PostTypeId="2" ParentId="102" CreationDate="2014-04-16T10:24:21.910" Score="11" Body="&lt;p&gt;According to wikipedia, there are around 5.5 million tonnes of &lt;a href=&quot;https://en.wikipedia.org/wiki/Uranium#Resources_and_reserves&quot; rel=&quot;nofollow noreferrer&quot;&gt;uranium in ore deposits&lt;/a&gt; that are commercially viable at current prices, and perhaps 35 million tonnes that are potentially viable if prices increase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also according to wikipedia, &lt;a href=&quot;https://en.wikipedia.org/wiki/Uranium#Biotic_and_abiotic&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Earth's crust&lt;/a&gt; (to 25 km depth) contains an estimated 10^14 tonnes (100 trillion tonnes), while the oceans may contain 10^10 tonnes (10 billion tonnes). This presumably includes the ore figures stated above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The previous link states that &quot;The decay of uranium, thorium, and potassium-40 in the Earth's mantle is thought to be the main source of heat&quot;, however no estimate is given for quantities. Allègre, Lewin and Dupré (1988) state that &quot;The concentration of U in the primordial mantle (bulk Earth) has been determined to be ~21±1 ppb&quot;. Back of the envelope calculations would then give us that the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mantle_%28geology%29&quot; rel=&quot;nofollow noreferrer&quot;&gt;mantle&lt;/a&gt; is 84% of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth&lt;/a&gt; by volume (probably slightly less than that by mass?), and the mass of the earth is 6*10^21 tonnes, which would give us, very approximately, 0.84 * (6*10^21) * (2.1*10^-8) ~= 10^14 tonnes, or roughly the same as is in the Earth's crust.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Allègre, C.J., Lewin, E. &amp;amp; Dupré, B., 1988. &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/0009254188900940&quot; rel=&quot;nofollow noreferrer&quot;&gt;A coherent crust-mantle model for the uranium-thorium-lead isotopic system.&lt;/a&gt; &#xA;Chemical Geology, 70(3), pp.211–234. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="56" LastEditorUserId="6093" LastEditDate="2016-12-05T12:18:50.943" LastActivityDate="2016-12-05T12:18:50.943" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="118" PostTypeId="1" AcceptedAnswerId="120" CreationDate="2014-04-16T10:26:50.437" Score="13" ViewCount="464" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Stratigraphy&quot;&gt;Stratigraphy&lt;/a&gt;, or study of rock or soil layers (strata), was originally introduced as a branch of geology. However, it is often applied in other disciplines, especially in archaeology and paleonthology. As an archaeologist (though not a field archaeologist), all I learnt about stratigraphy was taught from archaeological perspective. So I'm curious how the approach of other disciplines to stratigraphy differs from the archaeological. I'm especially interrested in geology - because it is the main and original discipline for stratigraphy, and because the geological time is very different from the archaeological time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know the basic principles such as &lt;a href=&quot;http://en.wikipedia.org/wiki/Law_of_superposition&quot;&gt;law of superposition&lt;/a&gt; and &lt;a href=&quot;http://en.wikipedia.org/wiki/Principle_of_original_horizontality&quot;&gt;principle of original horizontality&lt;/a&gt; are common. On the other hand, the time (hundreds or thousands of years x millions of years before present), materials on which stratigraphy is studied (sediments often created by human culture x rocks) and dating methods differ.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But how do these differences affect the &quot;theoretical&quot; methodology? That it is usually not possible to dig 100 million old strata with a spade is natural, but how about interpretation?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is geological stratigraphy visualized with &lt;a href=&quot;http://en.wikipedia.org/wiki/Harris-matrix&quot;&gt;Harris matrix&lt;/a&gt; or something very similar too? Are there any special principles that usually apply only on very old strata? Or is geological stratigraphy simpler, so some archaeological stratigraphy rules don't apply? Is there any distinctions between various stratigraphic units (layers and cuts, or other distinctions)? If yes, which categories are usually distinguished?&lt;/p&gt;&#xA;" OwnerUserId="101" LastEditorUserId="200" LastEditDate="2015-10-12T18:27:38.257" LastActivityDate="2022-12-01T18:43:00.263" Title="Which are the biggest methodological differences between the archaeological and geological approaches to stratigraphy?" Tags="|geology|stratigraphy|archaeology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="119" PostTypeId="2" ParentId="101" CreationDate="2014-04-16T10:27:46.980" Score="10" Body="&lt;p&gt;To explain the earth science bit (how a heat exchanger works is beyond the scope of the site). The Earth is essentially cooling, losing heat from the interior by conduction to space. this heat flux can be used to heat, for example water at depth since temperature increases with (significant) depth in the earth's crust. It is not necessary to be near a plate boundary although such locations may have anomalously large heat fluxes. A good example is Iceland. For an igneous plate, heat fluxes may average just above 40 milliwatts per square meter. In addition to pure heat flow out from the crust, heat is also generated within the bedrock due to radioactive decay. Measurements in Scandinavia shows that heat fluxes may vary between 30 and 82 miliwatt per square meter (Näslund et al. 2005). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hence there is an from a human perspective inexhaustible energy source that can be tapped into. the point is to use the ground eat to warm some liquid, usually water and use a heat exchanger (essentially a reversed refrigerator to extract, for example, heat for heating or hot water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Näslund, J., Jansson, P., Fastook, J., Johnson, J., &amp;amp; Andersson, L. (2005). Detailed spatially distributed geothermal heat-flow data for modeling of basal temperatures and meltwater production beneath the Fennoscandian ice sheet. Annals of Glaciology, 40, 95-101. doi:10.3189/172756405781813582&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="81" LastEditDate="2020-05-06T07:52:42.797" LastActivityDate="2020-05-06T07:52:42.797" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="120" PostTypeId="2" ParentId="118" CreationDate="2014-04-16T10:50:37.200" Score="6" Body="&lt;p&gt;As I see it there are no clear differences. There are, however, processes that are not compatible with a superposition principle. In geology, it is possible for layers to be folded and result in inverse age relationships. Packs of sediments can also be pushed over other layers during, for example mountain building, so that sequences are out of order or even repeated, almost like shuffling a deck of cards. It is also possible for, for example, magma to penetrate into rocks and generate much younger layers within an older rock mass. A depth, mass is added to the crust by melting and solidification while cooling such that rock units of different age can be found parallel (in a stratigraphic context) to each other. Hence the superposition principle only applies in sedimentary rocks and unconsolidated sediments that has not undergone and significant tectonic activity. But, I can also imagine that archaeological material can (although not extensively) be subject to disruptions in certain environments where active tectonics are at play or for example where glaciers act to push material forward and generate repeat sequences. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To expand on the second part of the post. Geological stratigraphy is established from physical exposures and by measuring structural shapes such as the strike and dip of strata (a branch of geology called &lt;a href=&quot;http://en.wikipedia.org/wiki/Structural_geology&quot;&gt;Structural geology&lt;/a&gt;. Very little is gained from created exposures such as open day mines, mine shafts of other dug pits. It is also possible (as in archaeology) to use geophysical methods to infer layer by ground penetrating radar, seismics etc. It should be mentioned here that methods and possibilities vary between bedrock and unconsolidated sediments, where I would venture to say that archaeology and studies of the unconsolidated sediments are very similar using test pits and coring with the addition of understanding transport mechanisms to understand how and why certain sediment layers exist where they are.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Visualisation pof geological data is usually done in sections or logs of boireholes with attempts to connect between observed sections. In bedrock where there is not only vertical variability but also significant horizontal, such as in igneous rocks, obtaining a precise image is very difficult&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="81" LastEditDate="2014-04-16T11:06:01.593" LastActivityDate="2014-04-16T11:06:01.593" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="121" PostTypeId="2" ParentId="102" CreationDate="2014-04-16T10:52:29.130" Score="5" Body="&lt;p&gt;The question &quot;how much&quot; is a little unprecise for geochemical questions. Rather you should think about:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-How much of the element is there per Rock-Volume (=Concentration)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The crust has a higher U-concentration than the mantle because U is drawn into the minerals that compose the crust. Or you could also say that the minerals that compose the mantle don't like to incorporate U. The same is true for the solid iron core and the iron melt that composes the outer core.&lt;/p&gt;&#xA;" OwnerUserId="23" LastActivityDate="2014-04-16T10:52:29.130" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="122" PostTypeId="2" ParentId="58" CreationDate="2014-04-16T11:07:55.763" Score="25" Body="&lt;p&gt;The Tibetan Plateau uplift is still generally considered as playing a role in the Neogene cooling through the process you explained in your question (see for instance the seminal &lt;strong&gt;Zachos et al. 2001&lt;/strong&gt; and more recently &lt;strong&gt;Garzione 2008&lt;/strong&gt;).&lt;br&gt;&#xA;It is probable that other phenomena played a role as well such as the diversification of diatoms (which are, today, the most efficient biological carbon sink, e. g. &lt;strong&gt;Goldman 1993&lt;/strong&gt;; &lt;strong&gt;Ragueneau et al 2000&lt;/strong&gt;) around 15 Ma (&lt;strong&gt;Lazarus et al 2014&lt;/strong&gt; &lt;em&gt;[Disclaimer: I am a co-author of the latter paper]&lt;/em&gt; ) or changes in the ocean circulation (specifically an increase in the proportion of bottom water originating from the Southern Ocean; &lt;strong&gt;Flower &amp;amp; Kennett 1994&lt;/strong&gt;).&lt;br&gt;&#xA;That being said, the cooling in question here would be the one starting at ca. 15 Ma. However the Cenozoic cooling trend started way earlier, in the Early Eocene (after the Early Eocene Climatic Optimum, aka EECO), with ice on the eastern Antarctic&#xA;continent as early as the Late Eocene / Early Oligocene (see again &lt;strong&gt;Zachos et al 2001&lt;/strong&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;&#xA;Sources:  &lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Flower, B. P. &amp;amp; Kennett, J. P., 1994. &lt;a href=&quot;http://dx.doi.org/10.1016/0031-0182%2894%2990251-8&quot;&gt;The middle Miocene climatic transition: East Antarctic ice sheet development, deep ocean circulation and global carbon cycling.&lt;/a&gt; Palaeogeography, Palaeoclimatology, Palaeoecology, 108: 537-555.&lt;/sub&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Garzione, C. N., 2008. &lt;a href=&quot;http://geology.gsapubs.org/content/36/12/1003.full&quot;&gt;Surface uplift of Tibet and Cenozoic global cooling.&lt;/a&gt; Geology, 36: 1003-1004.&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Goldman, J. C., 1993. &lt;a href=&quot;http://dx.doi.org/10.1016/0967-0637%2893%2990059-C&quot;&gt;Potential role of large oceanic diatoms in new primary production.&lt;/a&gt; Deep-Sea Research I, 40(1): 159-168.&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Lazarus, D., Barron, J., Renaudie, J., Diver, P., &amp;amp; Türke, A., 2014. &lt;a href=&quot;http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0084857&quot;&gt;Cenozoic Planktonic Marine Diatom Diversity and Correlation to Climate Change.&lt;/a&gt; Plos One, 9(1): e84857.&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;&#xA;Ragueneau, O., Tréguer, P., Leynaert, A., Anderson, R. F., Brzezinski, M. A., DeMaster, D. J., Dugdale, R. C., Dymond, J., Fischer, G., François, R., Heinze, C., Maier-Reimer, E., Martin-Jézéquel, E., Nelson, D. M., Quéguiner, B., 2000. &lt;a href=&quot;http://dx.doi.org/10.1016/s0921-8181%2800%2900052-7&quot;&gt;A review of Si cycle in the modern ocean: recent progress and missing gaps in the application of biogenic opal as a paleoproductivity proxy.&lt;/a&gt; Global and Planetary Change, 26: 317-365.  &lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Zachos, J., Pagani, M., Sloan, L., Thomas, E., Billups, K., 2001. &lt;a href=&quot;http://dx.doi.org/10.1126/science.1059412&quot;&gt;Trends, rhythms, and aberrations in global climate 65 Ma to Present.&lt;/a&gt; Science, 292:686-693.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-05-08T12:58:32.233" LastActivityDate="2014-05-08T12:58:32.233" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="123" PostTypeId="2" ParentId="105" CreationDate="2014-04-16T11:09:22.113" Score="3" Body="&lt;p&gt;Straight from &lt;a href=&quot;https://en.wikipedia.org/wiki/Aurora#Auroral_mechanism&quot; rel=&quot;nofollow&quot;&gt;wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Auroras are associated with the solar wind, a flow of ions&#xA;  continuously flowing outward from the Sun. The Earth's magnetic field&#xA;  traps these particles, many of which travel toward the poles where&#xA;  they are accelerated toward Earth. Collisions between these ions and&#xA;  atmospheric atoms and molecules cause energy releases in the form of&#xA;  auroras appearing in large circles around the poles. Auroras are more&#xA;  frequent and brighter during the intense phase of the solar cycle when&#xA;  coronal mass ejections increase the intensity of the solar wind.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Auroras result from emissions of photons in the Earth's upper&#xA;  atmosphere, above 80 km (50 mi), from ionized nitrogen molecules&#xA;  regaining an electron, and oxygen atoms and nitrogen molecules&#xA;  returning from an excited state to ground state. They are ionized&#xA;  or excited by the collision of solar wind and magnetospheric particles&#xA;  being funneled down and accelerated along the Earth's magnetic field&#xA;  lines; excitation energy is lost by the emission of a photon, or by&#xA;  collision with another atom or molecule:&lt;/p&gt;&#xA;  &#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;&lt;p&gt;&lt;strong&gt;oxygen emissions&lt;/strong&gt;: green or brownish-red, depending on the amount of energy absorbed.&lt;/p&gt;&lt;/li&gt;&#xA;  &lt;li&gt;&lt;p&gt;&lt;strong&gt;nitrogen emissions&lt;/strong&gt;: blue or red; blue if the atom regains an electron after it has been ionized, red if returning to ground state from an excited state.&lt;/p&gt;&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;  &#xA;  &lt;p&gt;Oxygen is unusual in terms of its return to ground state: it can take&#xA;  three quarters of a second to emit green light and up to two minutes&#xA;  to emit red. Collisions with other atoms or molecules absorb the&#xA;  excitation energy and prevent emission. Because the very top of the&#xA;  atmosphere has a higher percentage of oxygen and is sparsely&#xA;  distributed such collisions are rare enough to allow time for oxygen&#xA;  to emit red. Collisions become more frequent progressing down into the&#xA;  atmosphere, so that red emissions do not have time to happen, and&#xA;  eventually even green light emissions are prevented.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;This is why there is a color differential with altitude; at high&#xA;  altitude oxygen red dominates, then oxygen green and nitrogen&#xA;  blue/red, then finally nitrogen blue/red when collisions prevent&#xA;  oxygen from emitting anything. Green is the most common of all&#xA;  auroras. Behind it is pink, a mixture of light green and red, followed&#xA;  by pure red, yellow (a mixture of red and green), and finally, pure&#xA;  blue.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="56" LastActivityDate="2014-04-16T11:09:22.113" CommentCount="2" CommunityOwnedDate="2014-04-16T11:09:22.113" ContentLicense="CC BY-SA 3.0" />
  <row Id="124" PostTypeId="2" ParentId="71" CreationDate="2014-04-16T11:17:46.560" Score="5" Body="&lt;p&gt;About the limits: The largest depths on land are created by thinning of the lithosphere (Dead Sea rift as far as I know). The limit to this lowering is of course the inflow of the ocean (So the deepest point you can reach on dry land can only be slightly lower than the ocean water level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the ocean the deepest points are the places where the subducting plate pulls the lithosphere down into the astenosphere. The longer the attached subducting plate is (before it detaches), the stronger the force will be. It is probably difficult to say how deep a subduction trench can get because as it deepens it is also filled with sediments.&lt;/p&gt;&#xA;" OwnerUserId="23" LastActivityDate="2014-04-16T11:17:46.560" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="125" PostTypeId="2" ParentId="101" CreationDate="2014-04-16T11:27:13.173" Score="11" Body="&lt;p&gt;There are currently two ways to extract geothermal energy: one mainstream, one still at the experimental / demonstration level.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://dx.doi.org/10.1029/93RG01249&quot; rel=&quot;noreferrer&quot;&gt;Pollack et al (2010)&lt;/a&gt; estimate the global geoethermal heat loss at 44 TW (by comparison, civilisation's rate of energy use is about 20 TW).&lt;/p&gt;&#xA;&lt;p&gt;As the &lt;a href=&quot;http://www1.eere.energy.gov/geothermal/powerplants.html&quot; rel=&quot;noreferrer&quot;&gt;USA Department of Energy notes&lt;/a&gt;, all methods rely on the combination of three factors:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;heat&lt;/strong&gt; underground,&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;fluid&lt;/strong&gt; to carry the heat to the surface, and&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;permeability&lt;/strong&gt; to allow the fluid to flow.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;h3&gt;The mainstream geothermal method&lt;/h3&gt;&#xA;&lt;p&gt;This happens close to tectonic plate boundaries. Reservoirs of hot liquid are tapped, to bring the hot fluids to the surface. Typically the temperature of the fluids is well over 100 &amp;amp;degC;, and can be used for electricity generation, as well as for heating.&lt;/p&gt;&#xA;&lt;h3&gt;The experimental method is Hot Dry Rock&lt;/h3&gt;&#xA;&lt;p&gt;aka Enhanced Geothermal System or EGS.&lt;/p&gt;&#xA;&lt;p&gt;As Pavel V. commented, this is being &lt;a href=&quot;http://geomedia.cz/data/GMLitVal.pdf&quot; rel=&quot;noreferrer&quot;&gt;piloted in the Czech Republic&lt;/a&gt;, amongst other places, and allows geothermal heat extraction from places that are not close to tectonic plate boundaries. From that link:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;the projected depth of the ... borehole was between 2100 and 2500 m. The drilling diameter ranges from 393,7 mm for the starting upper section to 152 mm at the borehole bottom&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;One tube is placed inside another, inside the borehole. Water can be injected down the inner tube, and returned up through the gap between tubes, or the other way around.&lt;/p&gt;&#xA;&lt;p&gt;That paper reproduces the following chart from Šafanda, J., Dědeček, P., Krešl, M., Čermák, V. [2007] Report from geothermal research for PVGT-LT1 (in Czech):&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/iwWqD.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;As you can see, these temperatures are much lower, so are unsuitable for electricity generation, because one must accept very low efficiencies (Carnot's Law). They are used for space- and water-heating.&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-04-19T23:06:57.053" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="126" PostTypeId="1" CreationDate="2014-04-16T11:40:00.700" Score="20" ViewCount="416" Body="&lt;p&gt;This is a sort of a follow-up question to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/99/what-causes-the-earth-to-have-magnetic-poles&quot;&gt;What causes the Earth to have magnetic poles?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth has magnetic fields, and according to &lt;a href=&quot;http://en.wikipedia.org/wiki/Earth%27s_magnetic_field#Physical_origin&quot; rel=&quot;noreferrer&quot;&gt;dynamo theory&lt;/a&gt; I roughly understand why. If the Earth's rotation influences the Earth's magnetic field, it also seems natural that the poles will be orthogonal to the plane of rotation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I still don't understand few things:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Why are the magnetic poles positioned near, but not exactly at, the geographic poles?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Why do they drift over time?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Why does the Earth's magnetic field sometimes change polarity?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Are the changes in polarity based on some cycle? Can they be predicted?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="101" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-04-16T15:51:46.897" Title="Why Earth's magnetic poles are (and were) in their positions?" Tags="|geophysics|paleomagnetism|geomagnetism|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="127" PostTypeId="1" CreationDate="2014-04-16T11:45:40.173" Score="18" ViewCount="1901" Body="&lt;p&gt;&lt;em&gt;A question which has haunted me for years.&lt;/em&gt; What temperature do small meteorites (which don't evaporate on impact) have if you find them immediately after they hit the surface. I understand that the outer parts are heated by atmospheric friction, but what about the inside? Can the inside keep its low temperature that it inherits from space?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are some stories on the internet about meteorites that were so cold, that the moisture of the air froze on the surface of the meteorite. Can this really happen?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Subquestion:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Are there numerical simulations that can prove this?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Some of the rumours are summed up here:&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Talk:Meteorite#.22Frosty.22_meteorite&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;Frosty&quot; meteorite (Wikipedia)&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="23" LastEditorUserId="6093" LastEditDate="2017-01-11T09:59:11.267" LastActivityDate="2019-06-25T08:22:04.653" Title="What temperature do small meteorites have on impact" Tags="|meteorite|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="128" PostTypeId="1" CreationDate="2014-04-16T12:00:55.697" Score="12" ViewCount="938" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Vredefort_crater&quot;&gt;Vredefort Crater&lt;/a&gt; is one of the biggest known impact craters on earth. How deep would it have been, relative to the original ground height, immediately after the dust settled, and before any erosion kicked in? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a general relationship between the diameter of a meteorite crater and it's initial depth?&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2014-04-30T16:02:31.433" Title="How deep was the Vredefort Crater when it happened?" Tags="|geomorphology|meteorite|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="129" PostTypeId="2" ParentId="113" CreationDate="2014-04-16T12:06:42.440" Score="22" Body="&lt;p&gt;Tsunamis and sound waves are different types of wave - one is a transverse wave and the other is a longitudinal one. Let's look at the factors that influence the speed of each one.&lt;/p&gt;&#xA;&lt;h2&gt;Tsunami - transverse wave in shallow water&lt;/h2&gt;&#xA;&lt;p&gt;A transverse wave is one of the type that we think of from day to day - where the direction of oscillation is perpendicular to the direction of travel. The speed that a transverse wave travels at depends on different factors depending on the depth of the water. For this purpose, &amp;quot;shallow water&amp;quot; is usually defined as existing where depth &amp;lt; wavelength/20. The wavelength of a tsunami is very large - of the order of hundreds of kilometres - so for a tsunami, any part of the world's oceans counts as &amp;quot;shallow water&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;In shallow water, the speed of a transverse wave can be described by,&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$V = \sqrt{gD}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$V$&lt;/span&gt; is the wave's speed, &lt;span class=&quot;math-container&quot;&gt;$D$&lt;/span&gt; is the depth, and &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; is the acceleration due to gravity (9.81 m/s&lt;sup&gt;2&lt;/sup&gt;). In the case of a tsunami in the deep ocean, then, if we assume a depth of 4 km we can estimate a speed of 198 m/s, or 713 kph. That's a back-of-an-envelope calculation, but it's sufficiently similar to the 800kph that you quoted in the question that I'm happy with it.&lt;/p&gt;&#xA;&lt;h2&gt;Sound - longitudinal wave&lt;/h2&gt;&#xA;&lt;p&gt;In a longitudinal wave, the direction of the oscillation is parallel to the direction of travel - i.e. it's an oscillation in the &lt;em&gt;density&lt;/em&gt; of the material. We don't see many of these in everyday life, but one good example is the wave that moves down a slinky if you jerk the ends towards or away from each other.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/JpWFf.png&quot; alt=&quot;Picture of a slinky showing a longitudinal wave&quot; /&gt;&#xA;(&lt;a href=&quot;http://www.frankswebspace.org.uk/ScienceAndMaths/physics/physicsGCSE/transLong.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image source&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;Sound, in a liquid or a gas, is an example of a longitudinal wave. The speed of a longitudinal wave depends on the stiffness and the density of the material that it travels through, in the following way:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$c = \sqrt{\frac{K}{\rho}}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$c$&lt;/span&gt; is the speed of the wave, &lt;span class=&quot;math-container&quot;&gt;$K$&lt;/span&gt; is the bulk modulus of the fluid, and &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; is its density. Note that there is no dependence on the depth of the fluid (in this case the sea) - sound one metre below the surface of a salt water swimming pool would move at roughly the same speed as sound one meter below the surface of an ocean.&lt;/p&gt;&#xA;&lt;h2&gt;Summary&lt;/h2&gt;&#xA;&lt;p&gt;Sound waves and tsunami waves propagate through different mechanisms, and thus different things influence their speeds.&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2020-07-05T10:39:12.220" LastActivityDate="2020-07-05T10:39:12.220" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="130" PostTypeId="1" AcceptedAnswerId="214" CreationDate="2014-04-16T12:39:06.727" Score="15" ViewCount="1549" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Hydrocarbon&quot;&gt;&quot;Hydrocarbons&quot;&lt;/a&gt; are found in geological formations consisting of strata or layers of rocks. Specifically, they are formed from decomposed organic material (that contains carbon), that bonds with hydrogen, which is a component of water. (Somehow, the resulting oxygen is released).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Such hydrocarbons can take the form of either liquids (e.g. petroleum) or gas (natural gas). There are also &quot;intermediate&quot; products such as propane or butane that can easily take either liquid or gas form (at differing temperatures, but at temperature ranges that are normal for human existence).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What further factors cause hydrocarbons to take the form of petroleum, natural gas, or one of the others?&lt;/p&gt;&#xA;" OwnerUserId="42" LastEditorUserId="111" LastEditDate="2022-01-19T01:49:08.793" LastActivityDate="2024-02-28T05:10:25.637" Title="What causes &quot;hydrocarbons&quot; to take the form of petroleum versus natural gas?" Tags="|geology|petroleum|fossil-fuel|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="131" PostTypeId="2" ParentId="19" CreationDate="2014-04-16T12:57:07.497" Score="9" Body="&lt;p&gt;Weather models and forecasts are governed by systems of &lt;a href=&quot;http://en.wikipedia.org/wiki/Differential_equation&quot;&gt;differential equations&lt;/a&gt;. One starts with the current levels or values of causal variables: temperature, humidity, atmospheric pressure etc. One also has to factor in the &quot;derivatives,&quot; or rates of change of these variables. Hence the need for differential equations, which incorporate both variables and their derivatives to explain various &quot;wave&quot; phenomena such as heat, light, and sound, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even with the current large body of raw knowledge over large parts of the earth, forecasting the weather is still a dicey business, because of the apparent &quot;randomness&quot; of various variables. (Some of them are truly random, others get explained better over time.) By &quot;slicing and dicing&quot; variables, (and benefiting from past experience, weather forecasts have slowly but surely gotten more accurate over time over larger spaces. Increased computational power has also helped. (Extending the length of time for more accurate forecasts is trickier, because there are still too many moving parts.) For now, it seems that the tools that we have are a &quot;drop in the bucket&quot; compared to the size of the earth and universe (some weather patterns may be caused by things happening in interplanetary space), so it is truly amazing that we can often come up with weather forecasts that are more or less accurate. &lt;/p&gt;&#xA;" OwnerUserId="42" LastActivityDate="2014-04-16T12:57:07.497" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="132" PostTypeId="2" ParentId="60" CreationDate="2014-04-16T13:03:06.763" Score="10" Body="&lt;p&gt;I will answer mostly from archaeological perspective; I don't know much about the paleoclimatology before the first people started to produce stone tools. I know just some basics of other disciplines where they affect human (pre)history, but it might help.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, even though longer and older cold periods are also refered as &quot;&lt;a href=&quot;http://en.wikipedia.org/wiki/Ice_age&quot; rel=&quot;nofollow noreferrer&quot;&gt;ice ages&lt;/a&gt;&quot;, most people don't understand &quot;ice age&quot; as this, but as the time when our ancestors hunted mammoths. This is &quot;archaeological&quot; perspective. If you are interrested in the older geological history, &lt;a href=&quot;https://earthscience.stackexchange.com/a/63/101&quot;&gt;Joe Kington's answer&lt;/a&gt; explains the &quot;geological&quot; perspective better than I could. From this perspective, no ice age ended 10000 BC - the climate during current &quot;big Ice Age&quot; just went little milder.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've been told several times during paleolithic and paleoclimatology courses that according to current state of knowledge, there were 52 cold and the same number of warm periods during the quaternary. I didn't really try to find some more sources now, and I'm not sure whether the cold periods can all be classified as &quot;ice ages&quot;. I'm not sure, but I think that &lt;a href=&quot;http://en.wikipedia.org/wiki/B%C3%B8lling-Aller%C3%B8d&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bølling-Allerød interstadial&lt;/a&gt; is considered to be one of the warm period and &lt;a href=&quot;http://en.wikipedia.org/wiki/Younger_Dryas&quot; rel=&quot;nofollow noreferrer&quot;&gt;Younger Dryas&lt;/a&gt; might be an example of a cold period. If we divide the duration of quaternary by 52, we get around 50ky per cold + warm period; so either the 52 + 52 periods were longer and roughly regular, or Bølling-Allerød/ Younger Dryas drag the average length down, while ice ages lasting tens or hundreds thousands years drag the average up.&lt;br&gt;&#xA;Anyway, even if there were just four big Ice Ages during quaternary, as scientists expected few decades ago, they wouldn't last millions of years, and the rounding error would be much smaller than 10ky.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bølling-Allerød and Younger Dryas are especially relevant to your question, since they show that the last Ice Age (with maximum of glaciation around 20ky BP) didn't end suddenly, but that it ended for some 2000 years, then returned for some 1300 years and than ended for good (we usually mark this moment, around 11500 BP, as the beginning of Holocene). The prevailing theory is that the reason of the sudden cold shift is melting of a huge amount of ice, which decreased salinity of ocean water, slowing the Gulf stream down. So there is some &quot;rounding error&quot;, but we are out of its scope - I don't think there is enough ice to slow down the Gulf stream enough to trigger something that could be called &quot;ice age&quot; in the &quot;archaeological&quot; sense.&lt;/p&gt;&#xA;" OwnerUserId="101" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-04-29T18:08:53.287" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="134" PostTypeId="2" ParentId="90" CreationDate="2014-04-16T13:35:45.930" Score="4" Body="&lt;p&gt;Geophysics has many flavors to it. Prof Claerbout's site has a lot of free stuff which are a good introduction to one part of it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://sepwww.stanford.edu/sep/prof/&quot; rel=&quot;nofollow&quot;&gt;http://sepwww.stanford.edu/sep/prof/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="113" LastActivityDate="2014-04-16T13:35:45.930" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="135" PostTypeId="2" ParentId="103" CreationDate="2014-04-16T13:50:09.510" Score="10" Body="&lt;p&gt;The Coriolis force does not impart any difference in the draining of your sink or toilet, that has much more to do with the construction and design of the basin.  In fact, for Coriolis to do anything it needs hours to take effect.  The Coriolis effect requires large spatial and time scales.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can, however, look for its influence to determine which hemisphere you are in.   The obvious way to do this is to look at weather.  Mid-latitude cyclones and tropical cyclones center around low pressure, and the wind field around low pressure will swirl counter-clockwise in the North and clockwise in the South.  If you watch a large long-lived storm swirl, you know where you are (note that the direction of rotation of supercell thunderstorms and tornadoes is not due to Coriolis and cannot be used for this purpose).  Likewise with a high pressure system, the surface winds will swirl clockwise in the North and counter-clockwise in the south.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you don't have access to weather to make this determination but do have access to geographical surveys, you can inspect wear patterns on long sections of riverbank or railroad track.  These methods can be masked by other effects though, and are not as straightforward as using weather.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-04-16T13:50:09.510" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="136" PostTypeId="2" ParentId="12" CreationDate="2014-04-16T14:08:29.063" Score="16" Body="&lt;p&gt;First, inhomogeneities in the ocean are in fact quite common. There are density gradients in both horizontal and vertical directions and those gradients result in the baroclinic circulation of the ocean. The density gradients in the ocean are caused by salinity and temperature differences. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rossby waves are common in the ocean. They propagate along lines of latitude with the waves traveling along the Equator being the most obvious example and the most thoroughly studied. As in the case of atmospheric Rossby waves, their formation and propagation is related to the conservation of (potential) vorticity (rotational movement, angular momentum). A parcel of water has two sources of vorticity: its own spin and the planetary spin. When a parcel of water moves across a latitudinal line, its planetary spin (planetary vorticity) changes (as the Coriolis effect is latitudinally dependent) and, in order to conserve vorticity, it changes its own spin (relative vorticity). The water parcel tends to swing back and forth around the original latitude resulting in a wave-like motion. A Rossby wave is characterized by a westward phase velocity (that of the wave crests).&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2014-04-29T17:15:39.683" LastActivityDate="2014-04-29T17:15:39.683" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="137" PostTypeId="2" ParentId="31" CreationDate="2014-04-16T14:15:17.393" Score="6" Body="&lt;p&gt;This probably doesn't answer your question but might help the thought process:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The part of the carbon cycle you are inquiring about is referred to as the biological carbon pump.&lt;br&gt;&#xA;Phytoplankton total net primary productivity is estimated to be ca. 45 to 50x10&lt;sup&gt;15&lt;/sup&gt;g of (fixed) Carbon per year (&lt;strong&gt;Falkowski et al. 1998&lt;/strong&gt;). In comparison land plants are producing an estimated 50 to 60x10&lt;sup&gt;15&lt;/sup&gt;g of (fixed) Carbon per year (&lt;strong&gt;Field et al. 1998&lt;/strong&gt;), hence a roughly 50-50% situation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course not all of it is being buried: some is being recycled by heterotrophs and some decomposed (and thus released). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as the zooplankton and zoonekton (fishes, marine mammals, swimming molluscs and arthropods,...) are concerned, although I do not have numbers to back this claim, I would assume their impact on the carbon cycle to be (necessarily) smaller than that of the phytoplankton (since the carbon they are exporting comes, ultimately, from recycling the phytoplankton).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;&lt;sub&gt;Source:&lt;br&gt;&#xA;Falkowski, P. G., Barber, R. T., Smetacek, V., 1998. &lt;a href=&quot;http://dx.doi.org/10.1126/science.281.5374.200&quot; rel=&quot;nofollow noreferrer&quot;&gt;Biogeochemical Controls and Feedbacks on Ocean Primary Production.&lt;/a&gt; Science, 281: 200-207.&lt;br&gt;&#xA;Field, C. B., Behrenfield, M. J., Randerson, J. T., Falkowski, P., 1998. &lt;a href=&quot;http://dx.doi.org/10.1126/science.281.5374.237&quot; rel=&quot;nofollow noreferrer&quot;&gt;Primary Production of the Biosphere: Integrating Terrestrial and Oceanic Components.&lt;/a&gt; Science, 281: 237-240.&#xA;&lt;/sub&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2017-09-19T08:09:54.680" LastActivityDate="2017-09-19T08:09:54.680" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="138" PostTypeId="1" CreationDate="2014-04-16T14:27:04.927" Score="10" ViewCount="117" Body="&lt;p&gt;I study the fumarolic ice caves of Erebus Volcano, and am looking for published research on similar sorts of caves. My criteria for a &quot;fumarolic ice cave&quot; are that it must be:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A gas-filled void space in a snowpack large enough to fit humans&lt;/li&gt;&#xA;&lt;li&gt;Present because of geothermal or volcanic heat&lt;/li&gt;&#xA;&lt;li&gt;Not primarily present because of a flow of water&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So far, these are the fumarolic ice caves I know of:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The &lt;a href=&quot;http://dx.doi.org/10.1029/2011GL048272&quot;&gt;fumarolic ice caves&lt;/a&gt; of Mt. Erebus, Antarctica&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://dx.doi.org/10.1016/S0377-0273%2899%2900180-8&quot;&gt;The crater firn caves&lt;/a&gt; of Mt. Rainier, USA&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.caves.org/pub/journal/PDF/V60/V60N1-Anderson.pdf&quot;&gt;Crater firn caves&lt;/a&gt; of Mt. St. Helens, USA&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.oregongeology.org/pubs/og/OBv40n08.pdf&quot;&gt;Caves in Mt. Baker's Sherman Crater&lt;/a&gt;, USA&lt;/li&gt;&#xA;&lt;li&gt;Small fumarolic ice cave on Villarrica volcano, Chile (no reference, I've just been in it)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I imagine there are probably hundreds more and these things are common on glaciated volcanoes. I'd be particularly interested in references for Kamchatka and Iceland where I suspect I may not be able to find information because of the language barrier.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that I am not asking about rock-hosted caves with a permanent ice mass. &lt;/p&gt;&#xA;" OwnerUserId="63" LastEditorUserId="63" LastEditDate="2014-04-16T21:29:12.127" LastActivityDate="2014-04-16T21:29:12.127" Title="Any other fumarolic ice caves in the literature?" Tags="|volcanology|glaciology|" AnswerCount="0" CommentCount="6" ClosedDate="2014-04-18T17:55:05.063" ContentLicense="CC BY-SA 3.0" />
  <row Id="139" PostTypeId="1" AcceptedAnswerId="161" CreationDate="2014-04-16T14:41:53.633" Score="15" ViewCount="233" Body="&lt;p&gt;What supports the Rocky Mountains in North America? Or put another way, Why are they there? and Why are they still there?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It might be tempting to think of compression, especially in an east-west direction. However at the south end, New Mexico is experiencing east-west &lt;em&gt;extension&lt;/em&gt; (grabens including Rio Grande Rift Valley, plus associated volcanism).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hot spot and/or mantle plume uplift doesn't appear to explain them either. Yes there's the Yellowstone Hotspot under NW Wyoming. Regardless of whether this is really caused by a mantle plume or not, the related volcanism does not correlate with the mountains.&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2016-05-02T19:20:29.437" Title="What supports the Rockies?" Tags="|mountains|orogeny|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="140" PostTypeId="2" ParentId="3" CreationDate="2014-04-16T14:52:58.077" Score="5" Body="&lt;p&gt;There are a number of programs and instruments that sample the ocean autonomously. Examples of such programs are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The ARGO program (&lt;a href=&quot;http://www.argo.net/&quot; rel=&quot;noreferrer&quot;&gt;http://www.argo.net/&lt;/a&gt;): Currently around 3000 floats are freely drifting in the ocean measuring temperature, salinity and in some cases velocity of the upper 1000-2000 meters of the ocean. The floats drift for around 10 days most commonly at 1000 or 2000 meters and then conduct a vertical profile to the surface where they transfer the data to a satellite. &lt;/li&gt;&#xA;&lt;li&gt;RAFOS floats (&lt;a href=&quot;http://www.whoi.edu/instruments/viewInstrument.do?id=1061&quot; rel=&quot;noreferrer&quot;&gt;http://www.whoi.edu/instruments/viewInstrument.do?id=1061&lt;/a&gt;): They map the ocean currents using the SOFAR channel (a horizontal layer in the ocean where sound speed is minimum).&lt;/li&gt;&#xA;&lt;li&gt;Gliders (&lt;a href=&quot;http://www.ioos.noaa.gov/glider/&quot; rel=&quot;noreferrer&quot;&gt;http://www.ioos.noaa.gov/glider/&lt;/a&gt;): A type of autonomous underwater vehicle (AUV) that uses buoyancy to control its vertical position in the ocean. They sample along predetermined routes and can be equipped with instruments to measure temperature, salinity, turbidity, velocity...&lt;/li&gt;&#xA;&lt;li&gt;Other AUVs: Most other AUVs use propellers powered by rechargeable batteries and are able to carry a lot more instruments, but are limited to shorter missions.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Measuring oceanographic interior conditions remotely is much more challenging. While satellites provide data for sea surface (or near-surface) parameters, such as temperature (e.g., MODIS), salinity (SMOS &amp;amp; Aquarius), height (e.g., Jason 2) and color (SeaWiFS, MODIS), remote interior data are more challenging to acquire. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seismic oceanography is a recently developed technique that uses multichannel seismic reflection to characterize the ocean interior. It provides continuous mapping of the finer structure associated with the thermohaline (temperature and salinity) structure of the ocean. One of the best examples is Holbrook et al., 2003 Science paper (sciencemag.org/content/301/5634/821.full). You can find more information in: steveholbrook.com/research/seismic_oceanography and www.utm.csic.es/so&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2014-04-16T22:27:56.657" LastActivityDate="2014-04-16T22:27:56.657" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="141" PostTypeId="2" ParentId="88" CreationDate="2014-04-16T14:55:07.627" Score="16" Body="&lt;p&gt;Cavendish may have used a more direct approach, but Neville Maskelyn did it earlier in the &lt;a href=&quot;http://en.wikipedia.org/wiki/Schiehallion_experiment&quot;&gt;Schiehallion Experiment&lt;/a&gt; - publishing in 1778. Very much an Enlightenment story involving money left over from Cook's expedition to observe the Transit of Venus; Mason &amp;amp; Dixon; and even Benjamin Franklin was involved in the early planning.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Schiehallion is symmetrical and relatively isolated  mountain in Scotland. By measuring the shape (and inventing contour lines in the process!) it is possible to calculate the volume. From rock sampling, you can then calculate the mass of the mountain. Looking at pendulum deflection, you can calculate the ratio of the mass of the Earth to the mass of Schiehallion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using a modern Digital Terrain Model and geological models, Maskelyn's pendulum measurements give a result that agrees with the current accepted value of G (or M - they're two sides of the same coin).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an aside, I've hiked up the mountain about 18 months ago. If the weather is clear, you get some marvellous views as there aren't any mountains that close (which would also interfere with the measurements).&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2014-04-16T14:55:07.627" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="142" PostTypeId="2" ParentId="126" CreationDate="2014-04-16T15:00:51.633" Score="19" Body="&lt;p&gt;Actually, all of the three questions are directly related.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you noted, the Earth's magnetic field is generated by flow of molten conductive materials (probably mostly iron) in the outer core. (Contrary to popular belief, only the outer core and the oceans are liquid. The crust, mantle, and inner core are all solid. Solids can flow, but they have a shear strength. Liquids have no shear strength.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this flow is turbulent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, Earth's magnetic field can be described by having two poles, but in reality, it's much more complex.  Part of this is due to crustal structure (i.e. the magnetic anomalies we typically work with in geophysics to, say, locate an igneous intrusion or understand the evolution of the oceanic crust). However, the part that's due to crustal structure doesn't change rapidly and only influences a very small region.  The &quot;longer wavelength&quot; (i.e. broader) differences are due to variations in the flow of the outer core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Every &quot;eddy&quot; (i.e. any vorticity) in the flow produces its own magnetic field.  The sum of these is what produces the global magnetic field.  At the surface, we're a significant distance from the flow that produces the magnetic field.  Therefore, it gets &quot;smoothed out&quot; and these small perturbations are less apparent. It looks fairly close to a single magnetic dipole because the bulk of the flow is approximately around Earth's rotational axes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the answer to your first and second questions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The magnetic field is not the result of a single &quot;current&quot; of laminar flow, but rather the sum of much more complex turbulent flow.  Therefore, it doesn't exactly match the rotation axes, and the position of the magnetic poles changes over human timescales.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll hold off on answer the third question, as you split it into a separate question, but basically, the flow tends to self-organize, producing a strong magnetic field that's close to a single dipole.  Then, for reasons that aren't entirely clear, it episodically de-stabilizes (basically, you'd have multiple equally strong poles that somewhat cancel each other out), and then re-stabilizes (sometimes in the opposite direction).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you're interested in a &quot;pop-sci&quot; style writeup, there was a very nice &lt;a href=&quot;http://www.scientificamerican.com/article/probing-the-geodynamo-2005-07/?page=1&quot;&gt;Scientific American piece&lt;/a&gt; on this awhile back written by Glatzmaier (a very big name in the field).  Unfortunately, the web version is missing  the figures that were in the print version, but they're mostly from &lt;a href=&quot;http://www.es.ucsc.edu/~glatz/pub/glatzmaier_roberts_nature_1995.pdf&quot;&gt;Glatzmaier &amp;amp; Roberts, 1995&lt;/a&gt; or one of the follow-up papers by the same authors.&lt;/p&gt;&#xA;" OwnerUserId="12" LastEditorUserId="12" LastEditDate="2014-04-16T15:42:51.650" LastActivityDate="2014-04-16T15:42:51.650" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="143" PostTypeId="1" AcceptedAnswerId="169" CreationDate="2014-04-16T15:10:46.053" Score="16" ViewCount="865" Body="&lt;p&gt;I am aware that techniques exist for measuring surface currents using HF radar, either from &lt;a href=&quot;http://www.codar.com/&quot;&gt;land-based installations&lt;/a&gt; or from space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How do these work? I have assumed in the past that it's some sort of doppler system, but if I'm right about that, how are currents separated out from waves?&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2014-04-17T05:49:12.970" Title="How does remote sensing of ocean currents work?" Tags="|oceanography|ocean-currents|remote-sensing|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="144" PostTypeId="1" AcceptedAnswerId="156" CreationDate="2014-04-16T15:11:02.377" Score="18" ViewCount="1460" Body="&lt;p&gt;Mount Hood in Oregon is a dormant volcano, and in Washington Mount St. Helens and Mt. Ranier are both active volcanoes.  What causes this line of volcanoes running parallel to the coastline along the northwest coast of North America?&lt;/p&gt;&#xA;" OwnerUserId="53" LastEditorUserId="124" LastEditDate="2014-10-21T05:42:27.173" LastActivityDate="2016-12-14T16:21:27.193" Title="Why is there a line of volcanoes along the northwest coast of North America?" Tags="|geophysics|volcanology|plate-tectonics|geography|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="145" PostTypeId="2" ParentId="23" CreationDate="2014-04-16T15:15:18.693" Score="6" Body="&lt;p&gt;The large scale modes of variability present in the atmosphere are also found in the ocean. There is a strong feedback between the two systems with wind, heat flux and atmospheric pressure modifying ocean surface conditions and with parameters such as sea surface temperature altering atmospheric conditions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A lot of studies have explored teleconnections in the ocean looking for instance at the EOFs of sea surface temperature. A good compilation of different atmospheric and oceanic time series and references can be found in &lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/climateindices/list/&quot; rel=&quot;nofollow&quot;&gt;Climate Indices: Monthly Atmospheric and Ocean Time Series&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="6093" LastEditDate="2016-09-16T07:44:00.663" LastActivityDate="2016-09-16T07:44:00.663" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="146" PostTypeId="5" CreationDate="2014-04-16T15:22:02.757" Score="0" Body="&lt;p&gt;Geochemistry is the field that studies the chemical composition of natural systems. This includes rocks, water and air. The branch of cosmochemistry deals with extraterrestrial materials like meteorites or samples form other planets and moons.&lt;/p&gt;&#xA;" OwnerUserId="23" LastEditorUserId="23" LastEditDate="2014-04-16T17:40:21.270" LastActivityDate="2014-04-16T17:40:21.270" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="147" PostTypeId="4" CreationDate="2014-04-16T15:22:02.757" Score="0" Body="The science that uses the tools and principles of chemistry to explain the mechanisms behind major geological systems." OwnerDisplayName="user2872" LastEditorDisplayName="user2872" LastEditDate="2015-05-06T21:22:17.607" LastActivityDate="2015-05-06T21:22:17.607" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="148" PostTypeId="5" CreationDate="2014-04-16T15:32:22.430" Score="0" Body="&lt;p&gt;Uranium is an important element for the Earth's heat budget and acts as a natural clock in many minerals (different methods of Uranium dating). The heat of radioactive decay is harvested in nuclear power. The uncommon isotope 235U if purified can be used for nuclear weapons. The technological usage of Uranium can cause incredible environmental damage, which is why nuclear storage facilities for nuclear waste are a necessary step in the technological life cycle.&lt;/p&gt;&#xA;" OwnerUserId="23" LastEditorUserId="23" LastEditDate="2014-04-16T17:40:12.507" LastActivityDate="2014-04-16T17:40:12.507" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="149" PostTypeId="4" CreationDate="2014-04-16T15:32:22.430" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-16T15:32:22.430" LastActivityDate="2014-04-16T15:32:22.430" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="150" PostTypeId="1" AcceptedAnswerId="162" CreationDate="2014-04-16T15:48:36.497" Score="12" ViewCount="349" Body="&lt;p&gt;This question is related to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/133/what-causes-changes-in-the-polarity-of-earths-magnetic-field&quot;&gt;this question&lt;/a&gt; about the cause of the Earth's magnetic field switching polarity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: How does this switch in the polarity of the magnetic field affect life on Earth?  Will it have detrimental effects to living organisms?&lt;/p&gt;&#xA;" OwnerUserId="53" LastEditorUserId="32" LastEditDate="2014-04-16T16:26:28.693" LastActivityDate="2014-04-16T16:28:36.673" Title="What are the ramifications to life on Earth when the Earth's magnetic poles switch?" Tags="|geomagnetism|geobiology|astrobiology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="151" PostTypeId="2" ParentId="150" CreationDate="2014-04-16T15:58:25.730" Score="7" Body="&lt;p&gt;As far as I know there are no extinction phases that have been connected to a magnetic reversal. From this one can argue that there is no or only minor changes in the amount of radiation that reaches the Earth's surface. Life in the oceans and underwater anyway has an extra protective layer, i.e. water (but also see this as a grain of salt because most extinction events are recorded in the oceans, which are anyway protected).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are also some physics-models that say that a reversal is most likely not harmful. And migratory animals with magnetic sensors will adapt to the changes by simply migrating with their parents (The changes are so slow that the animals just slightly correct their compass bearing each generation)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source:&#xA;&lt;a href=&quot;http://www.geomag.bgs.ac.uk/education/reversals.html#6&quot;&gt;http://www.geomag.bgs.ac.uk/education/reversals.html#6&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="23" LastActivityDate="2014-04-16T15:58:25.730" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="152" PostTypeId="2" ParentId="144" CreationDate="2014-04-16T16:06:05.837" Score="4" Body="&lt;p&gt;It's because in this place two tectonic plates meet. Most volcanoes are in such place - where there is border between tectonic plates.&lt;/p&gt;&#xA;" OwnerUserId="109" LastActivityDate="2014-04-16T16:06:05.837" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="153" PostTypeId="2" ParentId="96" CreationDate="2014-04-16T16:09:44.857" Score="26" Body="&lt;p&gt;The water was already present when the Earth assembled itself out of the accretionary disk. Continued outgassing of volcanoes transferred the water into the atmosphere which was saturated with water. And rain transferred the water onto the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Compared to other planets and smaller solar system object Earth has a big advantage. It is large enough to prevent water molecules to leave the gravitational field, and it has a magnetic field which prevents atmospheric erosion &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_escape&quot; rel=&quot;noreferrer&quot;&gt;(Wikipedia).&lt;/a&gt; This is due to the Earth's outer core being liquid (Moving charged liquid = magnetic field). Mars probably had oceans until its outer core solidified so much, that the convection was stopped. After the magnetic field disappeared a few million years of solar radiation removed all of the atmosphere and the oceans.&lt;/p&gt;&#xA;" OwnerUserId="23" LastEditorUserId="6093" LastEditDate="2016-07-17T14:04:21.330" LastActivityDate="2016-07-17T14:04:21.330" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="154" PostTypeId="1" AcceptedAnswerId="660" CreationDate="2014-04-16T16:12:50.233" Score="24" ViewCount="929" Body="&lt;p&gt;The &lt;a href=&quot;http://en.wikipedia.org/wiki/Laki&quot; rel=&quot;noreferrer&quot;&gt;Laki fissure eruption of 1783/4&lt;/a&gt; in Iceland was not particularly large or explosive, but it is infamous for the large quantities of fluorine (or hydrofluoric acid) and SO&lt;sub&gt;2&lt;/sub&gt; that it produced, and the resulting local mass poisonings and Europe-wide vog (volcanic smog).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How come a number of Icelandic volcanoes are capable of producing hydrofluoric acid in such large quantities?&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorUserId="725" LastEditDate="2015-07-08T11:19:19.970" LastActivityDate="2017-08-21T01:12:02.483" Title="Why did the Laki eruption of 1783 produce so much fluorine?" Tags="|volcanology|volcanic-eruption|vog|hydrofluoric-acid|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="155" PostTypeId="2" ParentId="5" CreationDate="2014-04-16T16:13:07.713" Score="5" Body="&lt;p&gt;During El Niño heat is transferred from ocean to atmosphere. If atmosphere gets warmer, yes, it generates more radiation and more heat escapes into space. The same about land surface - if it's warmer, it radiates more heat. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course that's all with assumption that there are no other factors influencing it - like e.g. greenhouse gases.&lt;/p&gt;&#xA;" OwnerUserId="109" LastEditorUserId="111" LastEditDate="2014-12-21T21:53:28.560" LastActivityDate="2014-12-21T21:53:28.560" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="156" PostTypeId="2" ParentId="144" CreationDate="2014-04-16T16:15:24.137" Score="23" Body="&lt;p&gt;The Cascades (the volcanic range that Mt. St. Helens and Mt. Ranier are a part of) are &quot;arc volcanoes&quot; (a.k.a. &quot;a volcanic arc&quot;, etc).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Volcanic arcs form at a regular distance (and fairly regular spacing) behind subduction zones.  Subduction zones are areas where dense oceanic crust dives beneath more buoyant crust (either younger oceanic crust or continental crust).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The down-going oceanic plate begins to generate fluids due to metamorphic reactions that occur at a particular pressure and temperature.  These fluids cause partial melting of the mantle above the down-going slab.  (Contrary to what's often taught, the oceanic crust itself doesn't melt at this point - it's the mantle above it that does.)  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This causes arc volcanoes to form at the surface at approximately where the down-going oceanic slab reaches ~100km depth (I may be mis-remembering the exact number).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, there's an interesting story with the Cascades, the San Andreas Fault, and the Sierra Nevada.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically, Sierras are the old volcanic arc before an oceanic spreading ridge tried to subduct off the coast of California. (Search for the Farallon plate.) The ridge was too buoyant to subduct, so subduction stopped, shutting off the supply of magma to the volcanic arc.  Because the motion of the Pacific Plate (on the other side of the spreading ridge that tried to subduct) was roughly parallel to the margin of North America, a strike slip boundary formed instead: The San Andreas Fault.  Northward, there's still a remnant of the Farallon plate that's subducting beneath Northern CA, OR, WA, and BC.  Therefore, the Cascades are still active arc volcanoes, while the Sierras are just the &quot;roots&quot; of the old arc.&lt;/p&gt;&#xA;" OwnerUserId="12" LastEditorUserId="6703" LastEditDate="2016-12-14T16:21:27.193" LastActivityDate="2016-12-14T16:21:27.193" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="157" PostTypeId="5" CreationDate="2014-04-16T16:16:18.950" Score="0" Body="&lt;p&gt;A term for volcanic smog, popularized in Hawai'i where SO2 and dust particles from Kīlauea can drift over Honolulu and create a natural smog.&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorUserId="44" LastEditDate="2014-04-16T17:40:18.157" LastActivityDate="2014-04-16T17:40:18.157" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="158" PostTypeId="4" CreationDate="2014-04-16T16:16:18.950" Score="0" Body="Volcanic Smog formed from volcanogenic SO2 and dust particles." OwnerUserId="44" LastEditorUserId="44" LastEditDate="2014-04-16T17:41:38.357" LastActivityDate="2014-04-16T17:41:38.357" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="159" PostTypeId="2" ParentId="35" CreationDate="2014-04-16T16:16:27.327" Score="12" Body="&lt;p&gt;Sedimentation rate presently varies many orders of magnitude depending on the place you observe. The rate of sedimentation is also different. Some places have continual sedimentation, others have episodic sedimentation events.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is why charts that show changes in sedimentation rate are usually done for individual sedimentary basins, to determine the basin evolution. This is available for many basins, especially if they are of interest to the hydrocarbon industry.&lt;/p&gt;&#xA;" OwnerUserId="23" LastActivityDate="2014-04-16T16:16:27.327" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="160" PostTypeId="2" ParentId="13" CreationDate="2014-04-16T16:19:26.283" Score="5" Body="&lt;p&gt;Well, if there were no other factors, the temperature at the same isobar should be the same all over the Earth. But there are other factors, like winds, air mixing, albedo, ocean currents etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The temperature in atmosphere is lower at higher altitudes. That's because the air is gas, and it compresses. So the air at ocean level is denser than the air at 10km height. The air heats from the ground, and when it's getting warmer, it goes up. But because there is lower pressure, it expands, and while it's expanding, it cools down. That's why the higher you go - the colder it is. But if the pressure is not changing, the temperature shouldn't change too.&lt;/p&gt;&#xA;" OwnerUserId="109" LastActivityDate="2014-04-16T16:19:26.283" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="161" PostTypeId="2" ParentId="139" CreationDate="2014-04-16T16:21:11.540" Score="7" Body="&lt;p&gt;Part of the current topography might be due to a hot upper mantle below the Rocky mountains. This can be determined by seismic tomography. The hot mantle creates isostatic uplift.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just one of many pictures I found:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://srl.geoscienceworld.org/content/83/1/23/F2.large.jpg&quot; rel=&quot;nofollow&quot;&gt;http://srl.geoscienceworld.org/content/83/1/23/F2.large.jpg&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="23" LastEditorUserId="23" LastEditDate="2015-05-05T10:28:31.447" LastActivityDate="2015-05-05T10:28:31.447" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="162" PostTypeId="2" ParentId="150" CreationDate="2014-04-16T16:28:36.673" Score="9" Body="&lt;p&gt;While this does not directly answer the question, these two ideas are relevant: &lt;a href=&quot;http://en.wikipedia.org/wiki/Rare_Earth_hypothesis&quot;&gt;Rare Earth hypothesis&lt;/a&gt; and &lt;a href=&quot;http://en.wikipedia.org/wiki/Principle_of_mediocrity&quot;&gt;Mediocrity principle&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;More focused to the question, &lt;a href=&quot;http://www.nature.com/nature/journal/v217/n5123/abs/217046a0.html&quot;&gt;This letter to nature&lt;/a&gt; discusses the purposed link between evolution/mutation rate during of life and magnetic pole reversal periods. You see, when the magnetic fields reversed, it widely thought that it occurs over a period on the order of 1 - 10,000 years. During this reversal, the intensity of the magnetic field degrades to 0, and then increases from there in a reversed polarity. It is not a contentious position that during these field reversals the mutation rate (not sure about speciation rate) dramatically increases. &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-04-16T16:28:36.673" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="163" PostTypeId="2" ParentId="96" CreationDate="2014-04-16T16:39:03.887" Score="31" Body="&lt;p&gt;Your assumption that there is not a lot of water elsewhere in the solar system is incorrect.  According the &lt;a href=&quot;https://solarsystem.nasa.gov/yss/display.cfm?ThemeID=23&quot; rel=&quot;noreferrer&quot;&gt;this article&lt;/a&gt; on NASA's website;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Missions in recent years have overturned our view of a dry solar system, returning mounting evidence of ample water from a vast array of locations.&lt;/p&gt;&#xA;&lt;p&gt;Comets from the remote corners of our solar system are made of water and other ices. Orbiters, landers, and rovers reveal Mars as a watery world in the distant past -- a world that today may contain entire underground oceans of frozen water.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It also points out that&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Jupiter's moon Europa has a frozen crust of water, covering a thick global ocean. By current estimates, it has twice as much water as all of Earth's oceans and rivers!&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The perception that the rest of the solar system does not have a lot of water is probably due to the fact that the Earth is in the &lt;a href=&quot;http://en.wikipedia.org/wiki/Habitable_zone&quot; rel=&quot;noreferrer&quot;&gt;'Goldilocks zone'&lt;/a&gt; where water can exist in all three phases &lt;em&gt;at the surface&lt;/em&gt; of the planet.  The temperatures on the rest of the planets in the solar system are either so hot that it can only exist in a vapor phase or so cold that it can only exist in ice at the surface or liquid beneath.&lt;/p&gt;&#xA;" OwnerUserId="53" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-04-16T16:39:03.887" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="164" PostTypeId="2" ParentId="105" CreationDate="2014-04-16T16:43:32.057" Score="0" Body="&lt;p&gt;The Auroras are formed because a reconnection in the magnetic field. Particles are emitted by the Sun and collide with our magnetic field. This collision generates effects in the  ionosphere. You can read more about it in these links:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.atoptics.co.uk/highsky/auror2.htm&quot; rel=&quot;nofollow&quot;&gt;http://www.atoptics.co.uk/highsky/auror2.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://mrx.pppl.gov/Physics/physics.html&quot; rel=&quot;nofollow&quot;&gt;http://mrx.pppl.gov/Physics/physics.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="122" LastActivityDate="2014-04-16T16:43:32.057" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="165" PostTypeId="2" ParentId="144" CreationDate="2014-04-16T17:01:49.207" Score="10" Body="&lt;p&gt;In addition to Joe Kington's excellent answer; there is also a more complex process going on in the pacific northwest. As described in &lt;a href=&quot;http://www.nature.com/nature/journal/v482/n7385/full/nature10749.html?WT.ec_id=NATURE-20120216&quot;&gt;Nature&lt;/a&gt;, the origin of Columbia River Basalts is caused by the rupture of the of the subducted Farallon slab. The intense mantle flow weakened the slab to the point that the end decoupled from the &quot;main&quot; tectonic plate. The decoupled lithosphere is left to &quot;sink&quot; into the mantle without constraints from surface boundary conditions (kinematic) pushing hot mantle up under the pacific northwest. The pushing of this hot mantle provides an uncommonly abundant source of meltable mantle, resulting in increased volcanism. &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-04-16T17:01:49.207" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="166" PostTypeId="2" ParentId="17" CreationDate="2014-04-16T17:26:37.443" Score="11" Body="&lt;p&gt;You are correct that solar input on the Tibetan plateau will be the same as a location at sea level at the same latitude.  You are also correct that the Sun heats the Earths surface and that in turn heats the atmosphere.  Now for the rest of the details.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Albedo  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Albedo is a measure of &quot;whiteness&quot; and gives us an idea of how solar irradiance interacts with the Earth.  You probably know that dark colored things tend to get really hot when left in the sun, while light colored objects do not get as hot.  This is because when a photon from the Sun hits the Earth, it is either absorbed or scattered.  Without getting into the dynamics of radiation, I'll just leave it that dark colors tend to absorb and light colors tend toward scattering.  Now we translate this to albedo -- a high value &quot;white&quot; means solar input is being reflected back into the atmosphere; a low value means solar input is being absorbed.  A forest or ocean will have low albedo.  Snowpack and ice will have high albedo.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the albedo in Tibet on average is only slightly higher than average (~0.35 as cited in the comments below) and so this effect is limited with only a slight decrease in absorbed solar radiation than average.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Absorption&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The solar input that is absorbed in Tibet will excite the molecules in the ground and they will respond by warming up (and emitting longwave radiation).  The emitted radiation upward does nothing to the air temperature, only the greenhouse gases are good at absorbing these wavelengths, regular dry air is not.  It is notable that at these altitudes will also be less water vapor, which is probably the best greenhouse gas.  If radiation isn't going to warm the air, that leaves conduction and convection.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Conduction  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth heats the atmosphere via conduction with the lowest level of molecules in the atmosphere.  For conduction to happen, molecules need to touch.  At the lower pressures at high altitude, there are less molecules of air and conduction will be less efficient than at lower altitudes. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Atmosphere&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Air getting up to the Tibetan Plateau will have blown in, already at high altitude, or it will be blown upslope from lower elevations.  In either case, this air will tend to be cold and dry.  Upslope flow will tend to cool around 6C/km until it dries out (rain, clouds) and then cool at 10C/km.  For the air already at altitude, the average elevation of Tibet is around 580 hPa and the standard temperature at that pressure is -14 C.  Of these two effects, cool air advection of air already at this altitude dominates over upslope adiabatic flow .  This air at altitude tends to move faster than at the surface and you will have a constant flow of new incoming, cold air blowing over the surface of Tibet.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Putting it all together:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The slightly higher albedo is our first suspect as to why Tibet is colder than lower elevations at the same latitude -- more of the sunlight is reflected to space and does not contribute to warming the ground.  The next suspect is the less efficient heating of the atmosphere by the surface.  This is followed up by the atmosphere that is already much colder than the surface at sea level (at similar latitudes).  Take a much colder airmass than sea level, heat it up less than at sea level and you end up colder than you would be at sea level.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2014-04-18T20:15:58.213" LastActivityDate="2014-04-18T20:15:58.213" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="167" PostTypeId="1" AcceptedAnswerId="2975" CreationDate="2014-04-16T17:31:52.747" Score="15" ViewCount="492" Body="&lt;p&gt;Stromatolite fossils have a layered structure vaguely reminiscent of tree rings, which are a well-known source for climate data. Although the formation process of stromatolite layers is less seasonal than that of tree rings, it seems plausible that some information about environment conditions and changes in those conditions might be derived from stromatolite fossils. Having very close modern analogues in modern stromatolites might make interpreting such observations easier than for growth data from other fossils, and the great age of some stromatilite fossils might give at least a blurry window into such ancient environments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any potential for using stromatolite fossils to infer climatic (or other) conditions from billions of years ago?&lt;/p&gt;&#xA;" OwnerDisplayName="user26" LastEditorUserId="44" LastEditDate="2014-04-16T17:41:12.487" LastActivityDate="2014-12-07T08:21:30.713" Title="What, if any, paleoclimate data can be derived from stromatolite fossils?" Tags="|paleoclimatology|fossils|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="168" PostTypeId="1" AcceptedAnswerId="461" CreationDate="2014-04-16T17:34:42.573" Score="9" ViewCount="820" Body="&lt;p&gt;I have been looking for a proper way to create a netCDF file that is compliant with the &lt;strong&gt;Climate and Forecast (CF) Metadata Convention&lt;/strong&gt;. It is amazing that I can find a &lt;a href=&quot;http://cf-convention.github.io/compliance-checker.html&quot;&gt;compliance checker&lt;/a&gt; for NetCDF files at the CF-Metadata web page, but I have problems to find any tools or methods to create such a file. How can I create a CF-compliant netCDF file? Are there any good tools, which I can use?&lt;/p&gt;&#xA;" OwnerUserId="120" LastEditorUserId="124" LastEditDate="2014-04-21T22:12:37.380" LastActivityDate="2014-04-23T16:01:44.067" Title="How can I create a CF compliant netCDF file?" Tags="|oceanography|cf-metadata|" AnswerCount="1" CommentCount="10" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="169" PostTypeId="2" ParentId="143" CreationDate="2014-04-16T17:37:43.293" Score="13" Body="&lt;p&gt;I'm not familiar with land-based methods, but for global measurements, one method is to use satellite altimetry (I'm more familiar with the geodesy side, but many of the same satellites are used).  I think many of the current methods interpolate global or regional currents from a sparse network of buoys.  As more radar satellites are launched, however, satellite measurements of sea surface currents will become more common. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Global-scale satellite-based radar altimetry measures the average elevation of the ocean's surface over a few kilometers (the exact amount depends on the wavelength of the radar band being used).  Over this distance, waves cancel out, so the measurement is accurate to within a few centimeters.  (This is aided by using the motion of the satellite to enhance the image, referred to as Synthetic Aperture Radar (SAR).)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Surface currents in the ocean are directly related to the slope of the ocean's surface. (Again, at the scales we're working with, wind-formed waves cancel out.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once you have an accurate snapshot of the elevation of the ocean, you can calculate the direction and magnitude of the surface currents.  (Note that this is &lt;em&gt;only&lt;/em&gt; the surface currents! Deep ocean currents are different matter altogether.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is also how we coarsely map the ocean floor from space.  (For example, Sandwell &amp;amp; Smith's extensive work: &lt;a href=&quot;http://topex.ucsd.edu/WWW_html/mar_topo.html&quot;&gt;http://topex.ucsd.edu/WWW_html/mar_topo.html&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The average elevation of the ocean's surface with respect to center of the Earth follows the geoid (by definition).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seamounts on the ocean floor cause a preturbation in the geoid above them.  Water effectively &quot;bunches up&quot; around seamounts (or rather, the surface of gravitational equipotential &quot;bunches up&quot; above the seamount).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By repeatedly measuring the oceans surface (over several years) we can remove the effect of surface currents and get an accurate picture of what the geoid looks like over the ocean.  You can then use this to predict water depths over the oceans on a spatial scale of ~1 kilometer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact, to calculate surface currents, you need this information to begin with.  The surface currents are calculated as deviations from this measurement of the geoid.&lt;/p&gt;&#xA;" OwnerUserId="12" LastEditorUserId="12" LastEditDate="2014-04-16T17:50:35.743" LastActivityDate="2014-04-16T17:50:35.743" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="170" PostTypeId="1" AcceptedAnswerId="222" CreationDate="2014-04-16T17:39:04.077" Score="22" ViewCount="2809" Body="&lt;p&gt;I am writing my own MATLAB scripts to do most of the visualization and data analysis of model results. I wonder if there is a quicker way for visual comparison of simulation results gained from different ocean modeling systems. Is there a (preferably free) software package that works with CF (&lt;a href=&quot;http://en.wikipedia.org/wiki/Climate_and_Forecast_Metadata_Conventions&quot;&gt;Climate and Forecast Metadata Conventions&lt;/a&gt;) compliant NetCDF model output directly or is always some coding required? &lt;/p&gt;&#xA;" OwnerUserId="120" LastEditorUserId="124" LastEditDate="2016-07-25T19:17:16.543" LastActivityDate="2016-10-02T09:25:53.267" Title="What tools allow a quick comparison of NetCDF output from ocean models?" Tags="|ocean|oceanography|models|software|netcdf|" AnswerCount="7" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="171" PostTypeId="1" AcceptedAnswerId="175" CreationDate="2014-04-16T17:47:01.283" Score="11" ViewCount="560" Body="&lt;p&gt;The &lt;a href=&quot;http://www.yellowstonenationalpark.com/geysers.htm&quot;&gt;Yellowstone National Park&lt;/a&gt; in Wyoming is unique for its large number of &quot;thermal occurrences, of which there are some 30 geysers. This, in turn, appears to be the result of the presence of large quantities of molten rock, and the thinness of the earth's crust there, compared to the other spots on the earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To the best of my knowledge, there is no other (known) place on earth where so much thermal power is contained in a relatively small area. Is this in fact the case? If so, what made Yellowstone, Wyoming so unique in this regard?&lt;/p&gt;&#xA;" OwnerUserId="42" LastEditorUserId="42" LastEditDate="2019-06-23T15:57:23.597" LastActivityDate="2019-06-23T15:57:23.597" Title="Is the Yellowstone National Park unique for its geysers?" Tags="|geophysics|volcanology|geysers|geodynamics|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="172" PostTypeId="2" ParentId="170" CreationDate="2014-04-16T17:47:51.903" Score="4" Body="&lt;p&gt;While I don't know the specifics of ocean modeling, unless there there is a &quot;standard&quot; in which nodes are organized and written (Ie X,Y,Z), there will always be coding required. Furthermore, the way a a data file is written always depends on how tasks in the model are delegated to the processor: Is the model designed to be run on a personal PC or a Beowulf Cluster? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might be able to use something such as &lt;a href=&quot;http://www.opendx.org/&quot; rel=&quot;nofollow&quot;&gt;OpenDx&lt;/a&gt;, to compare ocean modeling results, though I still think that a quick python script would be in order to properly format all data types.  &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-04-16T17:47:51.903" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="173" PostTypeId="1" AcceptedAnswerId="176" CreationDate="2014-04-16T17:55:52.440" Score="13" ViewCount="1181" Body="&lt;p&gt;The Pacific Rim is pretty much defined by the so-called &lt;a href=&quot;http://en.wikipedia.org/wiki/Pacific_Ring_of_Fire&quot;&gt;&quot;Ring of Fire.&quot;&lt;/a&gt; It consists of the &quot;stomping ground&quot; for a disproportionate number of earthquakes and volcanoes, and the affected territory extends up and down the coast of North and South America, up and down the East Asian coast, and into the &quot;Australasian&quot; islands like Indonesia, the Philippines, and New Zealand. Apparently it has something to do with the presence (or absence) of tectonic plates  there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is there such a configuration of tectonic plates, and the resulting earthquakes and volcanoes in the Pacific, and not to the other oceans?&lt;/p&gt;&#xA;" OwnerUserId="42" LastEditorUserId="725" LastEditDate="2014-11-28T08:53:28.270" LastActivityDate="2014-11-28T08:53:28.270" Title="Why does the &quot;Ring of Fire&quot; pretty much define &quot;Pacific Rim&quot;" Tags="|plate-tectonics|earthquakes|volcanoes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="174" PostTypeId="1" AcceptedAnswerId="2742" CreationDate="2014-04-16T18:05:38.590" Score="33" ViewCount="11991" Body="&lt;p&gt;It is clear from Bowen's reaction series that more felsic minerals have lower melting points than mafic minerals. As far as I know, the same is true of quenched glasses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Felsics have a higher degree of SiO&lt;sub&gt;2&lt;/sub&gt; polymerization in the solid phase, which I would have thought was energetically favorable, and therefore I would have expected a felsic glass to require more energy to melt than a corresponding basaltic glass and therefore have a higher melting temperature. However, the opposite is true. Why is this the case?&lt;/p&gt;&#xA;" OwnerUserId="63" LastEditorUserId="725" LastEditDate="2014-11-28T08:55:32.923" LastActivityDate="2018-11-06T22:12:45.387" Title="Why do felsic materials have lower melting points than mafic?" Tags="|mineralogy|petrology|igneous|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="175" PostTypeId="2" ParentId="171" CreationDate="2014-04-16T18:13:21.000" Score="12" Body="&lt;p&gt;Yellowstone is thought to be above a &lt;a href=&quot;http://en.wikipedia.org/wiki/Mantle_plume&quot;&gt;mantle plume&lt;/a&gt;, of with there are tens to hundreds on our planet, although there is plenty of &lt;a href=&quot;http://geology.gsapubs.org/content/40/5/479.full&quot;&gt;debate on this matter&lt;/a&gt;. The exact nature of mantle plumes is a huge area of hotly contested research, but generally the are thought to be large melts originally sourced from the D'' layer (core / mantle boundary). Below the park, the plume is theorized to have resulted in magmatic intrusions overlain by a hydrothermal system. The intrusions can also be considered as magma chambers of a supervolcano, which has had several ultraplinean caldera-forming events. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Yellowstone hotspot is the only obvious expression of a mantle plume beneath the continental United States, which may be why you consider it &quot;unique.&quot; The other major plume / hotspot in the US is Hawaii.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yellowstone is certainly not the only major geothermal area in the world; geothermal areas in New Zealand, Italy, Japan and Antarctica are comparable in terms of heat flow. It's unclear what you mean by &quot;thermal power&quot; but Yellowstone park does not have any geothermal electric power generation plants. New Zealand, on the other hand, generates 13% of their national power needs geothermally.&lt;/p&gt;&#xA;" OwnerUserId="63" LastEditorUserId="63" LastEditDate="2014-04-16T18:27:26.023" LastActivityDate="2014-04-16T18:27:26.023" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="176" PostTypeId="2" ParentId="173" CreationDate="2014-04-16T18:14:34.517" Score="12" Body="&lt;p&gt;There isn't a concentration of tectonic plates - rather the opposite!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &quot;Ring of Fire&quot; is a pattern really. It is marked by subduction zones. So the question becomes, &quot;Why is the Pacific Ocean surrounded by subduction zones?&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Think back to Pangaea. This was a supercontinent that formed in the late Palaeozoic. Virtually all of the Earth's land masses were concentrated in one large supercontinent. When this broke up, the new continents moved away from each other. Fast forward 200Ma or so, and you find that the continents have moved so far apart that they are now converging on a point on the other side of the planet - the continents are moving towards each other! Hence the remains of the super ocean (which was actually multiple ocean plates - today's Pacific &amp;amp; Nazca plates, plus the Farrallon plate (RIP),etc ) is shrinking as the continental plates move towards it.&#xA;This destruction of the ocean plate(s) occurs at subduction zones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a big picture generalisation. Not all of the Pacific's boundaries are marked with subduction zones (e.g. North America has two large strike slip systems + a new spreading ridge). Also, not all of the continents are converging on each other. Africa is doing a pirouette, India is moving northwards, etc.&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2014-04-16T18:14:34.517" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="177" PostTypeId="2" ParentId="64" CreationDate="2014-04-16T18:30:18.800" Score="10" Body="&lt;p&gt;The answer to some parts of your question lie mainly in basic physics, there are a number of factors that will affect how a Tsunami will travel after the initial water displacement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, is the initial displacement a point event (such as Tsunami caused by landslides), or an event occurring along a long line, such as the massive fault movement that caused the &quot;Boxing Day&quot; Tsunami of 2004.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A point event allows the water to spread out in all directions from that point, similar to ripples in a pond after a raindrop or pebble falls in, the energy is dissipated equally in all directions and therefore the water displacement - and thus the height of the breaking Tsunami wave - decreases rapidly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Conversely, a linear event such as the &quot;Boxing Day&quot; tsunami doesn't allow the energy to dissipate equally in all directions, because at any given point along the wave-front, there is more &quot;wave&quot; to the 'left' and 'right' that prevent that dissipation. This allows the energy to be transferred over much greater distances, and allowing the water displacement to be preserved.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for why some land gets passed by, this is usually an effect of the local topography, going back to the Boxing Day Tsunami example, the Maldives were less effected than they could have been because there was no continental shelf for the waves to encounter and build up on. Bangladesh and other countries north of the fault-line also suffered less than they could have done because the northern and southern ends of the fault acted like point-events, and the waves to the north and south dissipated much more rapidly than those to the east and west.&lt;/p&gt;&#xA;" OwnerUserId="123" LastActivityDate="2014-04-16T18:30:18.800" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="178" PostTypeId="1" CreationDate="2014-04-16T18:43:58.653" Score="22" ViewCount="4207" Body="&lt;p&gt;The water close to the deep ocean floor is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Bottom_water&quot; rel=&quot;noreferrer&quot;&gt;bottom water&lt;/a&gt;.  It may be located in deep valleys or trenches.  I understand that water flowing to the Arctic will sink there, because it's saltier and therefore heavier than the surrounding water.  But once it sinks to the bottom, for example, inside trenches, what causes it to ever leave?  As far as I know, there aren't any significant sources of heat down at the ocean floor, like there are at the bottom of the atmosphere, but we still seem to have a highly dynamic system.  What causes this bottom water to mix again?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/06DOR.jpg&quot; alt=&quot;Thermohaline circulation&quot;&gt;&#xA;&lt;br /&gt;&lt;sup&gt;Figure obtained from &lt;a href=&quot;http://www.ocean.washington.edu/courses/envir202/Water_lecture_1.html&quot; rel=&quot;noreferrer&quot;&gt;University of Washington page&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="79" LastEditDate="2014-04-16T18:57:44.010" LastActivityDate="2014-05-05T19:01:18.880" Title="What causes bottom water to rise?" Tags="|ocean|oceanography|thermohaline-circulation|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="179" PostTypeId="5" CreationDate="2014-04-16T18:47:02.023" Score="0" Body="&lt;p&gt;Hydrology is the study of the properties and behaviour of water. It concerns both surface as well as subsurface water, although water in the oceans and atmosphere is generally excluded. Those are studied by &lt;a href=&quot;/questions/tagged/oceanography&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged &amp;#39;oceanography&amp;#39;&quot; rel=&quot;tag&quot;&gt;oceanography&lt;/a&gt; and &lt;a href=&quot;/questions/tagged/meteorology&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged &amp;#39;meteorology&amp;#39;&quot; rel=&quot;tag&quot;&gt;meteorology&lt;/a&gt;, respectively.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Typical subjects of hydrological studies are the hydrological cycle and water balance, the chemistry of the water, and flow patterns in surfacewater or groundwater. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The applications of hydrology are diverse, ranging from management of water resources, to prediction and prevention of floodings, droughts or landslides. Also the designs of sewer networks, bridges, canals, and hydro-electrical dams are heavily influenced by hydrological knownledge. Furthermore, hydrological concepts are sometimes also used outside the direct field of Earth Science, for example in modelling of urine flows in diapers.&lt;/p&gt;&#xA;" OwnerUserId="79" LastEditorUserId="79" LastEditDate="2014-04-17T14:01:10.303" LastActivityDate="2014-04-17T14:01:10.303" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="180" PostTypeId="4" CreationDate="2014-04-16T18:47:02.023" Score="0" Body="Hydrology is the study of the properties and behaviour of water. It concerns both surface as well as subsurface water, although water in the oceans and atmosphere is generally excluded. Those are studied by oceanography and meteorology, respectively." OwnerUserId="79" LastEditorUserId="87" LastEditDate="2014-04-19T22:25:04.897" LastActivityDate="2014-04-19T22:25:04.897" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="181" PostTypeId="2" ParentId="178" CreationDate="2014-04-16T18:50:09.107" Score="7" Body="&lt;p&gt;Some areas may well be relatively isolated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However water will come up when it is pushed from behind! E.g. there are strong sinks in the Norwegian Sea and Weddell Sea. This water must go somewhere and drives the deep water currents. These currents are pushed from behind and will come up when they hit a steep continental shelf. Such areas of upwelling water are often fertile ocean areas where the nutrient-rich deep waters reach the surface. E.g. offshore Namibia ( &lt;a href=&quot;http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=47178&quot;&gt;NASA photo&lt;/a&gt; ).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are sources of heat underwater, but they tend to be on the flanks of the mid ocean ridges (Black &amp;amp; White Smokers). These are actually the outlets of large convection systems which feed large quantities of ocean water through the young hot upper crust. However, they are relatively shallow and not in the ocean depths (and definitely not in the trenches).&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2014-04-16T18:50:09.107" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="182" PostTypeId="1" AcceptedAnswerId="3095" CreationDate="2014-04-16T18:55:07.960" Score="20" ViewCount="298" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_tide#Lunar_atmospheric_tides&quot;&gt;Lunar atmospheric tides&lt;/a&gt; are likely &lt;a href=&quot;http://www.scientificamerican.com/article/does-the-moon-have-a-tida/&quot;&gt;insignificant for weather&lt;/a&gt;, although &lt;a href=&quot;http://link.springer.com/article/10.1007%2FBF02918750&quot;&gt;Guoqing (2005)&lt;/a&gt; asserts that &lt;em&gt;The lunar revolution around the earth strongly influences the atmospheric circulation&lt;/em&gt;.  They don't seem to be studied terribly much.  What insights can we gain from the study of lunar atmospheric tides?&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2014-04-16T19:10:19.160" LastActivityDate="2014-12-21T21:41:05.280" Title="What can we learn by studying lunar atmospheric tides?" Tags="|atmosphere|tides|moon|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="183" PostTypeId="5" CreationDate="2014-04-16T19:09:38.057" Score="0" Body="&lt;p&gt;The &lt;a href=&quot;/questions/tagged/paleoclimatology&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged &amp;#39;paleoclimatology&amp;#39;&quot; rel=&quot;tag&quot;&gt;paleoclimatology&lt;/a&gt; tag concerns climate and climate variability before instrumented measurements begun. Paleoclimate studies are based on either proxy data or models. Proxy data can be ocean cores, dendrochronology, varves, peat, or other layered deposits which can be related to climate through process understanding.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="87" LastEditDate="2014-04-21T13:10:54.520" LastActivityDate="2014-04-21T13:10:54.520" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="184" PostTypeId="4" CreationDate="2014-04-16T19:09:38.057" Score="0" Body="Paleoclimatology concerns climate and climate variability before the onset of instrumented measurements." OwnerUserId="81" LastEditorUserId="87" LastEditDate="2014-04-21T13:11:06.547" LastActivityDate="2014-04-21T13:11:06.547" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="185" PostTypeId="1" CreationDate="2014-04-16T19:09:50.330" Score="8" ViewCount="533" Body="&lt;p&gt;The &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Turbopause&quot;&gt;turbopause&lt;/a&gt; separates (by definition) the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Homosphere&quot;&gt;homosphere&lt;/a&gt; from the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Heterosphere&quot;&gt;heterosphere&lt;/a&gt;.  What factors cause the turbopause to be where it is?  Is it affected by mesopheric composition, solar irradiance, global atmospheric change, and other factors that may change significantly?  Or is it mostly determined by density in the absolute sense, and therefore relatively constant?&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2014-11-28T08:58:43.390" Title="What factors determine the height of the turbopause?" Tags="|atmosphere|upper-atmosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="186" PostTypeId="2" ParentId="174" CreationDate="2014-04-16T19:11:09.793" Score="18" Body="&lt;p&gt;Good question! As you know, Bowen's reaction series describes the order of crystallization of silicate minerals in a cooling magma. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The complex anion of silicates is a tetrahedron of four oxygen atoms surrounding one silicon atom, connected with strong covalent bonds. Each tetrahedron may be isolated from one another or they may be bonded together covalently by sharing oxygen atoms between adjacent tetrahedra. In this way they may form single chains (pyroxene), double chains (amphibole), sheets (biotite), and three-dimensional networks of interlocking tetrahedra (quartz).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each of these covalently bonded structural groups (except 3D networks) is bonded to its neighboring structural group (e.g. single chain to single chain) by ionic bonds with intervening cations (K&lt;sup&gt;+&lt;/sup&gt;, Na&lt;sup&gt;+&lt;/sup&gt;, Ca&lt;sup&gt;2+&lt;/sup&gt;, Mg&lt;sup&gt;2+&lt;/sup&gt;, Fe&lt;sup&gt;2+&lt;/sup&gt;, etc.).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Relatively speaking, &lt;strong&gt;covalent bonds have lower melting points than ionic bonds.&lt;/strong&gt; &lt;a href=&quot;http://chemwiki.ucdavis.edu/Theoretical_Chemistry/Chemical_Bonding/Covalent_Bonds_vs_Ionic_Bonds&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Bowen's reaction series, the minerals that form at the cooler end of the discontinuous series are richer in silicon and oxygen and poorer in metal cations. Therefore, the minerals at the cooler end are also more dominated by covalent bonds over ionic bonds. &lt;strong&gt;This prevalence is the reason why felsic minerals melt at lower temperatures than mafic ones&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your logic is correct when looking at mineral stability in the face of chemical weathering. At the Earth's surface, those covalent bonds are much more stable and minerals like quartz tend to be much more resistant to weathering than olivine or pyroxene. This is described in the &lt;a href=&quot;http://www.columbia.edu/~vjd1/weathering.htm#Goldich&quot;&gt;Goldich stability series&lt;/a&gt;, which I like to think of as Bowen's reaction series stood on its head.&lt;/p&gt;&#xA;" OwnerUserId="112" LastEditorUserId="112" LastEditDate="2014-04-16T19:59:22.483" LastActivityDate="2014-04-16T19:59:22.483" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="187" PostTypeId="5" CreationDate="2014-04-16T19:17:57.960" Score="0" Body="&lt;p&gt;The &lt;a href=&quot;/questions/tagged/geomorphology&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged &amp;#39;geomorphology&amp;#39;&quot; rel=&quot;tag&quot;&gt;geomorphology&lt;/a&gt; tag concerns the landforms and exogenous processes of the surface of the Earth and or other solid surface planets. Geomorphological studies pairs understanding of processes altering the surface, both bedrock and unconsolidated sediments, resulting in typical landforms. this results in prediction of effects from processes on the landscape as well as interpretation of forms to quantify and understand processes from identified landforms or landform assemblages.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="81" LastEditDate="2014-04-17T14:00:59.207" LastActivityDate="2014-04-17T14:00:59.207" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="188" PostTypeId="4" CreationDate="2014-04-16T19:17:57.960" Score="0" Body="The [geomorphology] tag concerns the landforms and exogenous processes of the surface of the Earth or other solid surface planets." OwnerUserId="81" LastEditorUserId="81" LastEditDate="2014-04-17T14:02:52.207" LastActivityDate="2014-04-17T14:02:52.207" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="189" PostTypeId="1" CreationDate="2014-04-16T19:24:15.603" Score="8" ViewCount="66" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Argo_%28oceanography%29&quot;&gt;Argo probes&lt;/a&gt; broadcast surface measurements (among other things) on the worlds oceans, far away from traditional surface observations.  &lt;a href=&quot;http://link.springer.com/article/10.1007%2Fs00343-010-9017-2&quot;&gt;Yin et al. (2010)&lt;/a&gt; study the assimilation of these measurements in an ocean model, but according to an unsourced remark on Wikipedia:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;When a float transmits a profile it is quickly converted to a format that can be inserted on the GTS (Global Telecommunications System). The GTS is operated by the World Meteorological Organisation, or WMO, specifically for the purpose of sharing data needed for weather forecasting. Thus all nations who are members of the WMO receive all Argo profiles within a few hours of the acquisition of the profile.&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The ocean model by Yin et al. (2010) is not a weather forecasting model.  Are there any operational agencies that &lt;em&gt;actually use Argo probe data&lt;/em&gt; for numerical weather prediction?  Are there any publications on the impact this has had on forecast skill?&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="81" LastEditDate="2014-04-16T19:43:32.977" LastActivityDate="2014-04-16T22:44:15.787" Title="Are Argo probe data used for numerical weather prediction (NWP)?" Tags="|ocean|nwp|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="190" PostTypeId="5" CreationDate="2014-04-16T19:25:07.030" Score="0" Body="&lt;p&gt;NWP or &lt;strong&gt;Numerical Weather Prediction&lt;/strong&gt; is the use of numerical models to produce weather forecasts for operational purposes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See also &lt;a href=&quot;/questions/tagged/nowcasting&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged 'nowcasting'&quot; rel=&quot;tag&quot;&gt;nowcasting&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="56" LastEditDate="2015-04-09T07:32:45.970" LastActivityDate="2015-04-09T07:32:45.970" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="191" PostTypeId="4" CreationDate="2014-04-16T19:25:07.030" Score="0" Body="NWP is Numerical Weather Prediction: the use of numerical models to produce weather forecasts for operational purposes." OwnerUserId="6" LastEditorUserId="56" LastEditDate="2015-04-09T07:32:23.820" LastActivityDate="2015-04-09T07:32:23.820" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="192" PostTypeId="5" CreationDate="2014-04-16T19:27:08.413" Score="0" Body="&lt;p&gt;The &lt;a href=&quot;/questions/tagged/glaciology&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged &amp;#39;glaciology&amp;#39;&quot; rel=&quot;tag&quot;&gt;glaciology&lt;/a&gt; tag concerns all forms of ice and snow, frozen water, on earth or in space. The field of glaciology covers aspects such as materials science, chemistry, physics and climatology to understand the behaviour, composition, processes and existence of snow and ice. The International Association of Cryospheric Sciences (&lt;a href=&quot;http://www.cryosphericsciences.org&quot; rel=&quot;nofollow&quot;&gt;IACS&lt;/a&gt;) for example, provide five areas of snow and ice research to cover the field Snow and Avalanches, Glaciers and Ice sheets, Marine and Freshwater Ice, Cryosphere, Atmosphere and Climate, Planetary and other Ices of the Solar System,&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="81" LastEditDate="2014-04-17T14:01:13.197" LastActivityDate="2014-04-17T14:01:13.197" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="193" PostTypeId="4" CreationDate="2014-04-16T19:27:08.413" Score="0" Body="The [glaciology] tag concerns all forms of snow and ice on Earth and in space. And the marks left by ancient glaciers." OwnerUserId="81" LastEditorUserId="11908" LastEditDate="2018-02-01T01:19:56.217" LastActivityDate="2018-02-01T01:19:56.217" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="194" PostTypeId="1" AcceptedAnswerId="2221" CreationDate="2014-04-16T19:31:31.233" Score="10" ViewCount="113" Body="&lt;p&gt;The weather satellites &lt;a href=&quot;http://www.wmo-sat.info/oscar/satellites/view/306&quot;&gt;Metop-A&lt;/a&gt; and &lt;a href=&quot;http://www.wmo-sat.info/oscar/satellites/view/307&quot;&gt;Metop-B&lt;/a&gt; carry copies of the &lt;a href=&quot;http://www.wmo-sat.info/oscar/instruments/view/184&quot;&gt;High-Resolution Infrared Radiation Sounder&lt;/a&gt; (HIRS), an instrument with a heritage &lt;a href=&quot;http://www.wmo-sat.info/oscar/instruments/view/181&quot;&gt;back to 1975&lt;/a&gt;.  Considering that &lt;a href=&quot;http://www.wmo-sat.info/oscar/satellites/view/308&quot;&gt;Metop-C&lt;/a&gt; is part of &lt;a href=&quot;http://www.wmo-sat.info/oscar/satelliteprogrammes/view/44&quot;&gt;the same programme&lt;/a&gt; as Metop-A and Metop-B, a and operational satellites in the same programme normally carry the same payload, why is there no HIRS on Metop-C?&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="81" LastEditDate="2014-04-16T19:43:42.923" LastActivityDate="2014-07-04T17:21:43.720" Title="Why is there no High-Resolution Infrared Radiation Sounder (HIRS) on Metop-C?" Tags="|earth-observation|weather-satellites|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="195" PostTypeId="1" CreationDate="2014-04-16T19:43:25.200" Score="14" ViewCount="82" Body="&lt;p&gt;As early as the late 1960s / early 1970s, &lt;a href=&quot;http://www.wmo-sat.info/oscar/satellites/view/317&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nimbus-3&lt;/a&gt; carried &lt;a href=&quot;http://www.wmo-sat.info/oscar/instruments/view/228&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iris-B&lt;/a&gt; and &lt;a href=&quot;http://www.wmo-sat.info/oscar/satellites/view/318&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nimbus-4&lt;/a&gt; carried &lt;a href=&quot;http://www.wmo-sat.info/oscar/instruments/view/229&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iris-D&lt;/a&gt;, both infrared spectroradiometers with a moderate spectral resolution.  Subsequently, I believe it was not until &lt;a href=&quot;http://www.wmo-sat.info/oscar/instruments/view/16&quot; rel=&quot;nofollow noreferrer&quot;&gt;AIRS&lt;/a&gt; flew on &lt;a href=&quot;http://www.wmo-sat.info/oscar/satellites/view/79&quot; rel=&quot;nofollow noreferrer&quot;&gt;EOS-Aqua&lt;/a&gt; (launch 2002), and subsequently &lt;a href=&quot;http://www.wmo-sat.info/oscar/instruments/view/207&quot; rel=&quot;nofollow noreferrer&quot;&gt;IASI&lt;/a&gt; on &lt;a href=&quot;http://www.wmo-sat.info/oscar/satelliteprogrammes/view/44&quot; rel=&quot;nofollow noreferrer&quot;&gt;EPS&lt;/a&gt; and &lt;a href=&quot;http://www.wmo-sat.info/oscar/instruments/view/93&quot; rel=&quot;nofollow noreferrer&quot;&gt;CrIS&lt;/a&gt; on &lt;a href=&quot;http://www.wmo-sat.info/oscar/satelliteprogrammes/view/113&quot; rel=&quot;nofollow noreferrer&quot;&gt;SNPP&lt;/a&gt; and on &lt;a href=&quot;http://www.wmo-sat.info/oscar/satelliteprogrammes/view/87&quot; rel=&quot;nofollow noreferrer&quot;&gt;JPSS&lt;/a&gt;, that spectrometers were flown on (semi-)operational weather satellites.  Why is this so?  Were IRIS-B and IRIS-D considered unsuccessful, prohibitively expensive, or did agencies simply prioritise on other things?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT 2019-03-20&lt;/strong&gt;: There was actually one other hyperspectral interferometer: The &lt;a href=&quot;https://www.wmo-sat.info/oscar/instruments/view/1014&quot; rel=&quot;nofollow noreferrer&quot;&gt;Spectrometer Interferometer&lt;/a&gt; was &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/0094576580900156?via%3Dihub&quot; rel=&quot;nofollow noreferrer&quot;&gt;flown on several Meteor satellites&lt;/a&gt;.  The instrument was built by the &lt;em&gt;Academy of Sciences of German Democratic Republic (GDR), in collaboration with the former Soviet Hydrometeorological Service (HYDROMET) and the former Meteorological Service of GDR (Spänkuch 1980)&lt;/em&gt; and flew in the late 1970s / early 1980s.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2019-03-20T08:54:56.503" LastActivityDate="2019-03-20T08:54:56.503" Title="Why were no interferometers launched on weather satellites between the '69-'72 IRIS-D and the 2002-onward AIRS?" Tags="|earth-observation|weather-satellites|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="196" PostTypeId="1" CreationDate="2014-04-16T19:47:42.740" Score="9" ViewCount="92" Body="&lt;p&gt;E.g. see &lt;a href=&quot;http://www.wired.com/2014/04/el-nino-effects/&quot; rel=&quot;nofollow&quot;&gt;http://www.wired.com/2014/04/el-nino-effects/&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm thinking.. In case a major El Niño event didn't happen this year, then would it only make it more likely that a stronger El Niño would happen in a subsequent year?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="111" LastEditDate="2014-12-21T21:39:06.500" LastActivityDate="2014-12-21T21:39:06.500" Title="Are El Niños stronger when there is a longer gap from the last El Niño?" Tags="|atmosphere|enso|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="197" PostTypeId="5" CreationDate="2014-04-16T19:49:33.743" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-16T19:49:33.743" LastActivityDate="2014-04-16T19:49:33.743" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="198" PostTypeId="4" CreationDate="2014-04-16T19:49:33.743" Score="0" Body="concerning processes leading to large-scale deformation of the Earth's surface, particularly mountain-building events" OwnerUserId="105" LastEditorUserId="105" LastEditDate="2014-05-02T18:28:22.873" LastActivityDate="2014-05-02T18:28:22.873" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="199" PostTypeId="5" CreationDate="2014-04-16T19:59:41.193" Score="0" Body="&lt;p&gt;Fossils are the evidence of past life that has been preserved in rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As such, fossils can cover wide range of features. As well as the relatively common 'hard preservation' of common shells, they can include organic carbon films (e.g. leaves); isotope deviations (e.g. the hints of early ~3.5-4Ga life); chemical fossils (amino acids, keratin, breakdown products); casts (eg. at Pompeii); footprints; coprolites (fossil dung); regurgites (fossil vommit); burrows; and even buried cars, telephone boxes, etc ('technofossils') could be considered fossils.&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorUserId="44" LastEditDate="2014-06-16T15:33:59.707" LastActivityDate="2014-06-16T15:33:59.707" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="200" PostTypeId="4" CreationDate="2014-04-16T19:59:41.193" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-16T19:59:41.193" LastActivityDate="2014-04-16T19:59:41.193" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="201" PostTypeId="1" CreationDate="2014-04-16T20:00:27.357" Score="9" ViewCount="635" Body="&lt;p&gt;Convective &lt;a href=&quot;https://en.wikipedia.org/wiki/Overshooting_top&quot; rel=&quot;nofollow noreferrer&quot;&gt;overshooting tops&lt;/a&gt; &#xA;reach above the normally horizontal flat layer of the convective system, a layer that should coincide with the tropopause.  If we have such an overshooting top, does this mean we actually have the cloud reaching into the stratosphere, or does it mean that the convective system locally pushes the tropopause upward, while the convection is still limited to the (temporarily extended) troposphere?  Both alternatives are given as unsourced answers to &lt;a href=&quot;https://ca.answers.yahoo.com/question/index?qid=20120427041137AA6kWKW&quot; rel=&quot;nofollow noreferrer&quot;&gt;this identical Yahoo! Answers question&lt;/a&gt;, so I would like to see a referenced answer that &lt;em&gt;specifically&lt;/em&gt; addresses the distinction between &quot;air parcel reaches stratosphere&quot; or &quot;air parcel pushes tropopause upward&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;em&gt;Note that this is not merely a matter of terminology, but should affect troposphere-stratosphere interaction in general&lt;/em&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/0qHEM.jpg&quot; alt=&quot;Overshooting top&quot;&gt;&#xA;&lt;br /&gt;&lt;sup&gt;Source: &lt;a href=&quot;http://www.crh.noaa.gov/images/sgf/wxphotos/thunderstorms/711supercellsaloft_4.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="64" LastEditDate="2014-05-04T15:42:17.950" LastActivityDate="2014-05-04T15:42:17.950" Title="Can overshooting tops enter the stratosphere, or will they rather push the tropopause upward?" Tags="|meteorology|convection|clouds|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="202" PostTypeId="5" CreationDate="2014-04-16T20:00:47.177" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-16T20:00:47.177" LastActivityDate="2014-04-16T20:00:47.177" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="203" PostTypeId="4" CreationDate="2014-04-16T20:00:47.177" Score="0" Body="Petrology is the study of rocks and the processes that lead to their formation and alteration." OwnerUserId="23" LastEditorUserId="23" LastEditDate="2014-04-17T14:01:42.463" LastActivityDate="2014-04-17T14:01:42.463" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="204" PostTypeId="5" CreationDate="2014-04-16T20:02:51.673" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-16T20:02:51.673" LastActivityDate="2014-04-16T20:02:51.673" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="205" PostTypeId="4" CreationDate="2014-04-16T20:02:51.673" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-16T20:02:51.673" LastActivityDate="2014-04-16T20:02:51.673" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="206" PostTypeId="5" CreationDate="2014-04-16T20:04:03.973" Score="0" Body="&lt;p&gt;Climate is the long-term average weather sitation for a particular area on Earth and for a particular time of year. Since this average is measured of multiple years, or even decades a climate is relatively stable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For questions on climate change see &lt;a href=&quot;/questions/tagged/climate-change&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged 'climate-change'&quot; rel=&quot;tag&quot;&gt;climate-change&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For questions on ancient climates (before the use of weather instruments) see &lt;a href=&quot;/questions/tagged/paleoclimatology&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged 'paleoclimatology'&quot; rel=&quot;tag&quot;&gt;paleoclimatology&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For questions on mathematical models of climates see &lt;a href=&quot;/questions/tagged/climate-models&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged 'climate-models'&quot; rel=&quot;tag&quot;&gt;climate-models&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1109" LastEditorUserId="1109" LastEditDate="2014-12-05T08:59:40.280" LastActivityDate="2014-12-05T08:59:40.280" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="207" PostTypeId="4" CreationDate="2014-04-16T20:04:03.973" Score="0" Body="Average weather conditions for a particular area measured over multiple years or decades.&#xD;&#xA;For questions on climate change use the [climate-change] tag." OwnerUserId="1109" LastEditorUserId="1109" LastEditDate="2014-12-05T09:27:03.847" LastActivityDate="2014-12-05T09:27:03.847" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="208" PostTypeId="5" CreationDate="2014-04-16T20:04:27.270" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-16T20:04:27.270" LastActivityDate="2014-04-16T20:04:27.270" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="209" PostTypeId="4" CreationDate="2014-04-16T20:04:27.270" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-16T20:04:27.270" LastActivityDate="2014-04-16T20:04:27.270" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="210" PostTypeId="5" CreationDate="2014-04-16T20:05:39.853" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-16T20:05:39.853" LastActivityDate="2014-04-16T20:05:39.853" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="211" PostTypeId="4" CreationDate="2014-04-16T20:05:39.853" Score="0" Body="Resources are essential commodities required by every organism, and usually come at a prize, and are connected with trade-offs." OwnerUserId="23" LastEditorUserId="23" LastEditDate="2014-04-17T14:00:54.947" LastActivityDate="2014-04-17T14:00:54.947" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="212" PostTypeId="1" CreationDate="2014-04-16T20:12:59.403" Score="6" ViewCount="162" Body="&lt;p&gt;In particular, I'm interested in the heat contained in the stratosphere, mesophere, and thermosphere.&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="124" LastEditDate="2014-04-17T20:39:29.903" LastActivityDate="2016-03-04T11:07:33.503" Title="How much total heat is contained in the upper layers of the atmosphere?" Tags="|atmosphere|upper-atmosphere|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="213" PostTypeId="1" CreationDate="2014-04-16T20:15:58.023" Score="12" ViewCount="998" Body="&lt;p&gt;As quoted over &lt;a href=&quot;http://www.wired.com/2014/04/el-nino-effects/&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;. This is especially interesting to me because El Niño tends to warm up the climate, and warmer climates are generally associated with weaker jet streams.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;El Niño has other effects further into North America. It tends to enhance the jet stream, creating a wall that prevents Arctic air (and the Polar Vortex) from dipping down to mid-latitudes. East Coast winters are generally drier and warmer during El Niño years, which is probably good news to those still smarting from this recent frigid season. The mild winter has interesting downstream effects, like a boost for the U.S. economy during the Christmas season.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="10" LastEditorUserId="111" LastEditDate="2014-12-21T21:39:51.853" LastActivityDate="2015-01-13T08:10:09.007" Title="Why does El Niño enhance the jet stream?" Tags="|atmosphere|enso|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="214" PostTypeId="2" ParentId="130" CreationDate="2014-04-16T20:26:00.143" Score="10" Body="&lt;p&gt;Oil and gas both form when organic matter is buried under anoxic conditions, such that it isn't oxidised and subsequently mineralised to the elemental components of the hydrocarbons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What hydrocarbons are formed depends on both burial depth and temperature. Above approximately 1km below the surface no significant formation of oil takes place, and hydrocarbons are either mineralised or broken down to volatile products such as methane, propane, and butane.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The often so called 'oil window' is located below 1km, but above ~4km, and at temperatures between 40-50&amp;#8239;&amp;#176;C and 150&amp;#8239;&amp;#176;C. Under these conditions long hydrocarbon chains can form without being broken down to shorter, more volatile chains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At larger depths or higher temperatures no (significant amount of) oil is formed, and all organic matter is transformed to natural gas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/6HtSS.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;br&gt;&#xA;An approximate graph after Nichols (2009).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Formation of these fossil fuels often takes place in shales (lithified clay) that are rich in organic matter, but as all sedimentary rocks this is a porous medium and thus liquids will tend to flow upwards to areas of lower pressure. To be preserved two other components are therefore necessary: a reservoir rock (often sandstone) and a sealing rock (numerous types of rock are suitable, including rock salt and certain igneous rocks), often in dome or fault structures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Source:&lt;/strong&gt; Nichols, Gary (2009) &lt;em&gt;Sedimentology and Stratigraphy&lt;/em&gt;, p 293-295&lt;/p&gt;&#xA;" OwnerUserId="79" LastActivityDate="2014-04-16T20:26:00.143" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="215" PostTypeId="2" ParentId="86" CreationDate="2014-04-16T20:41:08.887" Score="11" Body="&lt;p&gt;You know, there hasn't been &lt;em&gt;too&lt;/em&gt; much research into this... but there has been some. For the most part, it's been proven that a green sky most likely means that a &lt;em&gt;thunderstorm&lt;/em&gt; is coming. According &lt;a href=&quot;http://www.news.wisc.edu/15301&quot;&gt;to a researcher&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Green is significant, &lt;strong&gt;but not proof that a tornado is on the way&lt;/strong&gt;. A&#xA;  green cloud “will only occur if the cloud is very deep, which&#xA;  generally only occurs in thunderstorm clouds,” Bachmeier says. “Those&#xA;  are the kind of storms that may produce hail and tornadoes.” Green&#xA;  does indicate that the cloud is extremely tall, and since&#xA;  thunderclouds are the tallest clouds, green is &lt;strong&gt;a warning sign&lt;/strong&gt; that&#xA;  large hail or a tornado may be present.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In addition, &lt;a href=&quot;http://www.scientificamerican.com/article/fact-or-fiction-if-sky-is-green-run-for-cover-tornado-is-coming/&quot;&gt;a Scientific American article was run on this&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Over the past 15 years, a small group of scientists have weathered the elements working on green thunderstorms as a pet project, publishing a handful of articles in meteorological journals. &lt;strong&gt;All point to the existence of green skies with severe thunderstorms but no direct connection to tornadoes or hail can be made.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They then go on to state:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Threatening green skies during a thunderstorm also proved entirely&#xA;  independent of the type of severe weather that came with it. Gallagher&#xA;  measured hailstorms where the dominant wavelength of light was green&#xA;  as well as hailstorms where it was the typical gray-blue color of&#xA;  thunderstorms. &lt;strong&gt;Tornado-producing storms proved similarly divorced from&#xA;  any particular sky color, other than dark.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;We do know that green skies are a sign of thunderstorms, though:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The moisture particles are so small that they can bend the light and&#xA;  alter its appearance to the observer. These water droplets absorb red&#xA;  light, making the scattered light appear blue. If this blue scattered&#xA;  light is set against an environment heavy in red light—during sunset&#xA;  for instance—and a dark gray thunderstorm cloud, the net effect can&#xA;  make the sky appear faintly green.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So to sum all of this up: we know that thunderstorms sometimes create a green sky. However, there is no evidence to prove that a green sky is a sure sign of a tornado or hail. It is however a warning sign, as it shows that a thunderstorm is most likely coming, and it could be a strong storm.&lt;/p&gt;&#xA;" OwnerUserId="20" LastActivityDate="2014-04-16T20:41:08.887" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="216" PostTypeId="1" AcceptedAnswerId="259" CreationDate="2014-04-16T20:52:53.570" Score="9" ViewCount="450" Body="&lt;p&gt;In magnetostratigraphic logs various chrons are distinguished with either normal or reversed polarity, with the magnetic north pole at the geographic north and south pole, respectively. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How and why can these polarities be determined? Note that I'm not after the quantummechanical reasons for magnetism, but how rocks store the magnetic orientation and how this information can later be retrieved from the rock.&lt;/p&gt;&#xA;" OwnerUserId="79" LastEditorUserId="725" LastEditDate="2014-11-28T09:02:47.370" LastActivityDate="2014-11-28T09:02:47.370" Title="How are paleomagnetic polarities determined?" Tags="|mineralogy|paleomagnetism|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="217" PostTypeId="2" ParentId="216" CreationDate="2014-04-16T20:52:53.570" Score="6" Body="&lt;p&gt;The paleomagnetic field is recorded initially by minerals with a magnetic dipole, which is lined up with the surrounding magnetic field as long as the temperature is above the so called Curie Point. When these minerals cool down below this temperature the dipole is 'frozen' and fixed until the mineral is exposed again to a higher temperature. Different minerals have their Curie Point at different temperatures, so you'll seldomly find a rock with a single paleomagnetic orientation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To later measure this orientation most often sample cores are drilled from the rock, carefully recording the original orientation of the core and analysed in a magnetometer. This device is shielded from the surrounding magnetic fields which are invariably stronger than the magnetic dipole stored in the sample. By either heating the sample or exposing it to a electromagnetic field the magnetic field in the sample is detected.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;After this is determined one must carefully reconstruct the paleoorientation of the sample at the time the magnetic field was captured, by reconstructing the tectonic history of the sample, which might include regional folding or faulting, or rotation of plates.&lt;/p&gt;&#xA;" OwnerUserId="79" LastActivityDate="2014-04-16T20:52:53.570" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="218" PostTypeId="1" AcceptedAnswerId="348" CreationDate="2014-04-16T21:10:48.907" Score="11" ViewCount="691" Body="&lt;p&gt;Looking at seismic noise around the Earth there is commonly a peak in the seismic noise around a frequency of 200 mHz.  This peak is typically referred to as the microseism (an example is shown below).  What is the source of these low frequency oscillations.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From experience I know that in southern Louisiana the motion at this peak is generally stronger throughout the winter than in the summer.  I have also been told that it is associated with water waves in the gulf, but it is unclear how those waves get converted to ground motion tens of miles inland.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/9Re1N.png&quot; alt=&quot;Seismic noise taken from www.ligo.caltech.edu/~jharms/data/Plots/Histograms/GR_MOX_BHZ_specvar.png&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="53" LastEditorUserId="53" LastEditDate="2014-04-19T15:02:03.950" LastActivityDate="2014-04-19T15:02:03.950" Title="What generates the microseism?" Tags="|seismology|microseism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="219" PostTypeId="1" AcceptedAnswerId="220" CreationDate="2014-04-16T21:11:47.210" Score="4" ViewCount="326" Body="&lt;p&gt;For those confused about the title, there's a joke that every moderator has a &quot;diamond hammer&quot; (diamond from the little &lt;code&gt;♦&lt;/code&gt; by the username). In a &lt;a href=&quot;http://chat.stackexchange.com/transcript/11540?m=14796232#14796232&quot;&gt;chat discussion&lt;/a&gt;, it was brought to my attention that a diamond &lt;em&gt;can&lt;/em&gt; burn (which makes total sense because it's pure carbon) after I got a notification in orange in the topbar of SE.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyway my question is &lt;strong&gt;why can something so durable be able to burn?&lt;/strong&gt; I would imagine that there would be a relationship between flammability and durability, especially since metal cannot burn.* Is it just a coincidence that most people think hard == inflammable? Why &lt;em&gt;can&lt;/em&gt; diamond burn?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*It can burn when oxidized IIRC.&lt;/p&gt;&#xA;" OwnerUserId="55" LastEditorUserId="725" LastEditorDisplayName="user889" LastEditDate="2016-05-10T09:39:09.590" LastActivityDate="2016-05-10T09:39:09.590" Title="Why is my ♦ hammer (i.e. diamond) so durable, but it can burn?" Tags="|geology|geochemistry|mineralogy|diamond|" AnswerCount="1" CommentCount="7" ClosedDate="2014-04-18T02:55:54.260" ContentLicense="CC BY-SA 3.0" />
  <row Id="220" PostTypeId="2" ParentId="219" CreationDate="2014-04-16T21:19:15.420" Score="11" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;It is bond strength, not hardness, that determines how easily oxygen&#xA;  can attack and burn a material, allowing me to burn a diamond in a&#xA;  pool of liquid oxygen resting in a block of graphite.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Diamond is hard because its bonds form an inflexible, three-dimensional lattice. However, the strength of these bonds themselves is not even as strong as graphite, for example. Graphite has much stronger bonds, but they create &quot;sheets,&quot; which can slide around, making graphite softer but harder to burn.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&lt;a href=&quot;http://www.popsci.com/diy/article/2009-08/burn-diamonds-torch-and-liquid-oxygen&quot;&gt;(source)&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Indeed, &lt;a href=&quot;http://io9.com/how-and-why-to-make-a-diamond-burn-637183425&quot;&gt;people have burned diamonds before by putting them in tubes of pure oxygen&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="127" LastActivityDate="2014-04-16T21:19:15.420" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="221" PostTypeId="1" CreationDate="2014-04-16T21:20:35.310" Score="12" ViewCount="657" Body="&lt;p&gt;Does the shape of the fault that the earthquake originated from determine its ratio of high frequency to low frequency waves?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What about shallow-fault vs deep subduction zone earthquakes?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="725" LastEditDate="2014-11-29T07:31:53.723" LastActivityDate="2016-01-25T22:23:33.833" Title="What determines the spectrum of high and low frequency waves emitted by an earthquake?" Tags="|seismology|earthquakes|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="222" PostTypeId="2" ParentId="170" CreationDate="2014-04-16T21:55:37.347" Score="18" Body="&lt;p&gt;The writers of netCDF, &lt;a href=&quot;http://www.unidata.ucar.edu&quot;&gt;UNIDATA&lt;/a&gt;, maintain a &lt;a href=&quot;http://www.unidata.ucar.edu/software/netcdf/software.html&quot;&gt;pretty extensive list&lt;/a&gt; of visualisation software on the netCDF website.  It even mentions an Excel add-in, for the masochistic, presumably.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Over the years, I've found &lt;a href=&quot;http://ferret.pmel.noaa.gov/Ferret/&quot;&gt;Ferret&lt;/a&gt; to be reliable with CF compliant files (and non-compliant ones, for that matter) and useful for interactive quick looks and simple manipulations.  It understands, for example, the CF-recommended UDUNITS time format and will automatically apply &lt;code&gt;scale_factor&lt;/code&gt; and &lt;code&gt;add_offset&lt;/code&gt; attributes to variables.  It's certainly quicker to get something on screen than the Python/R/Matlab route that I usually take for presentation and publication quality plots.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you're after a more GUI-like viewer, then I've heard good things about &lt;a href=&quot;http://www.giss.nasa.gov/tools/panoply/&quot;&gt;Panoply&lt;/a&gt;, although I must admit I've never used it myself.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2014-04-16T21:55:37.347" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="223" PostTypeId="2" ParentId="114" CreationDate="2014-04-16T22:02:40.967" Score="16" Body="&lt;p&gt;A clue is in the full name of the hill: 'Butte Montmartre'. A butte is an erosional feature in which a block of resistant rock overlies a less resistant layer. Erosion of the soft layer below causes the more resistant rock to erode as well by undercutting. This can lead to an isolated hill in a relatively flat surrounding.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Montmartre hill itself consists of relatively resistant sedimentary rocks (can't find what exactly, although Deffontaines (2005) and De Wever (2002) hint at sandstones and shales) overlying soft marls and gypsum, which was mined until 1860, also contributing to instability of the butte (Deffontaines, 2005). Evaporite-diapirism, as mentioned by Spießbürger, might therefore have played a role as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Deffontaines, B., B. Fruneau, A. Prunier-Leparmentier, A. Arnaud, R. Cojean, E. Pajot, J. Rudant (2005) &lt;a href=&quot;http://www.geotech-fr.org/sites/default/files/congres/geoline/GEOLINE2005%20S4%20pp%201-7%20Deffontaines.pdf&quot;&gt;&lt;em&gt;Urban instability revealed by DINSAR and SPN Interferometry: The Montmartre &quot;Funiculaire&quot; case example (Paris, France)&lt;/em&gt;&lt;/a&gt;. Géoline 2005&lt;br&gt;&#xA;De Wever, P., F. Guillocheau, J. Reynaud, E. Vennin, C. Robin, A. Cornée, D. Rouby (2002) &lt;a href=&quot;http://dx.doi.org/10.1016/S1631-0683%2802%2900071-4&quot;&gt;&lt;em&gt;Deux siècles de stratigraphie dans le bassin de Paris&lt;/em&gt;&lt;/a&gt;. Comptes Rendus Palevol&lt;/p&gt;&#xA;" OwnerUserId="79" LastEditorUserId="79" LastEditDate="2014-04-17T05:53:56.127" LastActivityDate="2014-04-17T05:53:56.127" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="224" PostTypeId="1" AcceptedAnswerId="459" CreationDate="2014-04-16T22:03:52.940" Score="8" ViewCount="131" Body="&lt;p&gt;&lt;a href=&quot;http://www.pbs.org/wgbh/nova/next/nature/animals-as-oceanographers/&quot;&gt;This article&lt;/a&gt; says that mounting sensors on animals is relatively cheap compared with the alternatives.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Seals, in other words, were filling in the blind spots on oceanographer’s maps. And they were doing it relatively cheaply—at least compared to the cost of ships or Argo floats, the international network of probes that transmit real-time measurements of the Earth’s oceans.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But how much cheaper? &lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="124" LastEditDate="2014-05-21T09:58:52.440" LastActivityDate="2014-05-21T09:58:52.440" Title="How much cheaper is it to mount oceanographic sensors on elephant seals and other animals, compared using Argo floats and other abiotic sensors?" Tags="|ocean|in-situ-measurements|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="225" PostTypeId="1" CreationDate="2014-04-16T22:08:54.043" Score="14" ViewCount="2069" Body="&lt;p&gt;&lt;strong&gt;Numerical models&lt;/strong&gt; of the atmosphere usually &lt;strong&gt;have their first atmospheric grid level well above 2 m&lt;/strong&gt;, but the temperature at 2 m above ground level is something one often wants to calculate with such a model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These models have some surface scheme to calculate temperatures at / in the ground and solve (approximated) Navier–Stokes equations on the atmospheric grid. Heat fluxes between these model components are usually parameterized with the help of &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Monin-obukhov_similarity_theory&quot;&gt;Monin–Obukhov similarity theory&lt;/a&gt;. Hence, a &lt;strong&gt;diagnostic calculation of the 2 m temperature is needed&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What needs to be done to get a reasonable 2 m temperature?&lt;/strong&gt; Is a simple use of a diagnostic formula using surface layer similarity again enough? What could be done based on data, assuming many simulations and observations are available?&lt;/p&gt;&#xA;" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2014-04-17T23:48:26.497" LastActivityDate="2014-04-17T23:48:26.497" Title="How can I estimate a 2 m temperature from / in an atmospheric model?" Tags="|atmosphere|meteorology|models|nwp|mos|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="226" PostTypeId="5" CreationDate="2014-04-16T22:10:00.637" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-16T22:10:00.637" LastActivityDate="2014-04-16T22:10:00.637" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="227" PostTypeId="4" CreationDate="2014-04-16T22:10:00.637" Score="0" Body="MOS (Model Output Statistics) is applied to improve the output of models used for numerical weather prediction." OwnerUserId="124" LastEditorUserId="124" LastEditDate="2014-04-19T22:25:53.463" LastActivityDate="2014-04-19T22:25:53.463" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="228" PostTypeId="1" AcceptedAnswerId="229" CreationDate="2014-04-16T22:24:44.310" Score="11" ViewCount="2843" Body="&lt;p&gt;What is the Calcite Compensation Depth (CCD) and what is its significance for carbonate deposits? &lt;/p&gt;&#xA;" OwnerUserId="79" LastActivityDate="2024-02-22T18:14:12.697" Title="What is the Calcite Compensation Depth and what is its significance for carbonate deposits?" Tags="|oceanography|geochemistry|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="229" PostTypeId="2" ParentId="228" CreationDate="2014-04-16T22:24:44.310" Score="7" Body="&lt;p&gt;The Calcite Compensation Depth is the depth below which all calcite minerals are dissolved. The solubility of calcite depends on both pressure and temperature. Under high pressure, low temperature conditions calcite is most soluble, and in deep parts of the ocean only siliceous deposits are found.&lt;/p&gt;&#xA;&lt;p&gt;Typical values for the CCD are between 3000 and 4000 m, but since the CCD also depends on the amount of calcite in the water it can occur as shallow as 2500 m (in parts of the Pacific Ocean).&lt;/p&gt;&#xA;&lt;p&gt;Taking all this together it becomes clear carbonate deposits can form and/or be preserved only above the CCD.&lt;/p&gt;&#xA;" OwnerUserId="79" LastEditorUserId="29921" LastEditDate="2024-02-22T18:14:12.697" LastActivityDate="2024-02-22T18:14:12.697" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="230" PostTypeId="2" ParentId="225" CreationDate="2014-04-16T22:30:41.133" Score="13" Body="&lt;p&gt;Your premise is incorrect.&lt;/p&gt;&#xA;&lt;p&gt;Numerical models normally have:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A full temperature profile&lt;/li&gt;&#xA;&lt;li&gt;&lt;em&gt;A specific field&lt;/em&gt; for the 2 metre temperature&lt;/li&gt;&#xA;&lt;li&gt;&lt;em&gt;A specific field&lt;/em&gt; for the skin temperature&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;For example, see &lt;a href=&quot;http://data-portal.ecmwf.int/data/d/era40_daily/&quot; rel=&quot;noreferrer&quot;&gt;ERA-40 daily fields&lt;/a&gt;, which both &lt;em&gt;2 metre temperature&lt;/em&gt; and &lt;em&gt;Skin temperature&lt;/em&gt;, or &lt;a href=&quot;http://rda.ucar.edu/datasets/ds093.0/&quot; rel=&quot;noreferrer&quot;&gt;CFS reanalysis 6-hour fields&lt;/a&gt;, which has &lt;em&gt;Air temperature&lt;/em&gt;, &lt;em&gt;Skin temperature&lt;/em&gt;, and &lt;em&gt;Surface air temperature&lt;/em&gt;, (I think surface air temperature means 2-metre temperature, but check their full documentation to be sure).&lt;/p&gt;&#xA;&lt;p&gt;It is not accurate to take the lowest temperature level in the temperature profile for either of the two, nor to interchange skin temperature with 2-m temperature.  But, in some cases, the data distribution may be such that &lt;em&gt;either or both of these are actually attached to the temperature profile&lt;/em&gt;.  For example, &lt;a href=&quot;http://rda.ucar.edu/datasets/ds093.1/#docs/FAQs_hrly_timeseries.html&quot; rel=&quot;noreferrer&quot;&gt;the CFS hourly timeseries&lt;/a&gt; has the question:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Where is Sea Surface Temperature (SST) in CFSR? Where is Skin Temperature?&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;CFSR does not label SST and skin temperature grids differently than temperature grids on other levels. Select the parameter 'Temperature' and the level 'Ground or water surface' to obtain the SST/skin temperature grids, and then use the land/sea mask to determine whether a gridpoint is over water (SST) or land (skin temperature).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;(I had the opposite problem, needing skin temperature, and being tempted to use 2 metre temperature instead, until I realised where the data were).&lt;/p&gt;&#xA;&lt;p&gt;If you encounter a model that really &lt;em&gt;only&lt;/em&gt; has the full temperature profile, then I would contact the authors to inquire.  Maybe it is a model that really only does well in the free atmosphere, and is not suitable for the extraction of (near-) surface temperatures.  The boundary layer can be a hard thing to model!&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-04-16T22:37:27.630" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="231" PostTypeId="2" ParentId="85" CreationDate="2014-04-16T22:32:46.070" Score="19" Body="&lt;p&gt;It's not too too likely, but it can happen. A few earthquakes have either been attributed to fracking, or the wastewater produced from fracking.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;http://www.usgs.gov/blogs/features/usgs_top_story/man-made-earthquakes/&quot;&gt;the USGS&lt;/a&gt; (for more information, visit that page):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Many questions have been raised about whether hydraulic fracturing —&#xA;  commonly known as “fracking”— is responsible for the recent increase&#xA;  of earthquakes. &lt;strong&gt;USGS’s studies suggest that the actual hydraulic&#xA;  fracturing process is only very rarely the direct cause of felt&#xA;  earthquakes.&lt;/strong&gt; While hydraulic fracturing works by making thousands of&#xA;  extremely small “microearthquakes,” they are, with just a few&#xA;  exceptions, too small to be felt; none have been large enough to cause&#xA;  structural damage. As noted previously, &lt;strong&gt;underground disposal of&#xA;  wastewater co-produced with oil and gas, enabled by hydraulic&#xA;  fracturing operations, has been linked to induced earthquakes.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, indeed, the disposal of wastewater has been linked to earthquakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://geology.gsapubs.org/content/early/2013/03/26/G34045.1.abstract&quot;&gt;This study in Geology&lt;/a&gt; also came to the same conclusion that the wastewater of fracking caused earthquakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.huffingtonpost.com/2014/04/11/ohio-earthquakes-fracking_n_5136110.html&quot;&gt;An additional study produced by Ohio geologists&lt;/a&gt; concluded that a few small earthquakes were due to fracking. I do wonder exactly what they concluded, but the news story doesn't say. It does say this, but it doesn't say exact what this study was, either:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A U.S. government-funded report released in 2012 found that two worldwide instances of shaking can be attributed to actual extraction of oil and gas, as opposed to wastewater disposal in the ground — a magnitude-2.8 quake in Oklahoma and a magnitude-2.3 quake in England. Both were in 2011.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="20" LastActivityDate="2014-04-16T22:32:46.070" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="232" PostTypeId="2" ParentId="189" CreationDate="2014-04-16T22:44:15.787" Score="5" Body="&lt;p&gt;One of the issues with ARGO data is that in most cases it does not provide data from the real surface of the ocean. When they ascend from their drifting depth (usually at 1000 or 2000 meters) to the surface, most of them stop recording at a depth of around 5 meters from the surface. From SeaBird (the company that provides the CTD sensors in most ARGO floats, SSalOceanSciencesMar08-5Pages.pdf‎): &quot;...to avoid degrading the salinity accuracy by ingesting sea surface contaminants, the pump is turned off at approximately 5 decibars beneath the surface as the Argo float ascends.&quot; This creates problems when assimilating into atmospheric models because of inconsistencies between the satellite-derived sea surface temperature and the ARGO temperature at 5 meters. To address this issue and provide better surface flux information, some ARGO floats are equipped with a second temperature and salinity sensor (STS) that only measures in the proximity of the surface.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-04-16T22:44:15.787" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="233" PostTypeId="1" AcceptedAnswerId="253" CreationDate="2014-04-16T23:01:34.393" Score="17" ViewCount="22906" Body="&lt;p&gt;Most of the water cycle studies focus on the processes and changes occurring over land with little emphasis on the ocean. Meanwhile, the ocean covers almost 3/4 of the surface of Earth. How much of the global precipitation and evaporation takes place over the ocean? Is it 75% of the total? If the percentage is higher, why does that occur?&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2023-12-04T17:35:26.483" Title="What is the percentage of the global water cycle (evaporation, precipitation) that occurs over the ocean?" Tags="|ocean|precipitation|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="234" PostTypeId="1" AcceptedAnswerId="237" CreationDate="2014-04-16T23:14:19.477" Score="22" ViewCount="641" Body="&lt;p&gt;Since 2009, two satellites (SMOS from ESA and Aquarius from NASA) are providing global salinity measurements. While ocean temperature is easily derived from infrared radiation for instance, what parameter is measured by those satellites to estimate the salinity of the ocean?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="64" LastEditDate="2014-04-29T15:17:48.457" LastActivityDate="2014-04-29T15:17:48.457" Title="How is ocean salinity measured from space?" Tags="|ocean|oceanography|remote-sensing|salinity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="235" PostTypeId="2" ParentId="221" CreationDate="2014-04-16T23:22:51.490" Score="9" Body="&lt;p&gt;There are several factors that determine the spectrum of wave frequencies of earthquakes. They include the &lt;a href=&quot;http://faculty.weber.edu/bdattilo/shknbk/notes/msrngerthqks.htm&quot;&gt;following:&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Size of the earthquake. All other things being equal, the larger the earthquake, the larger the spectrum of frequencies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) The texture of the rocks or other materials. Hard materials have a wider range of frequencies than soft materials.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) The ratio of &quot;body&quot; to surface waves. Waves emanating from the body of the earthquake have higher total frequencies (and greater variation), than waves emanating from the surface of the ground.&lt;/p&gt;&#xA;" OwnerUserId="42" LastActivityDate="2014-04-16T23:22:51.490" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="236" PostTypeId="1" AcceptedAnswerId="254" CreationDate="2014-04-16T23:44:26.113" Score="20" ViewCount="16497" Body="&lt;p&gt;It is well known that the Earth's rotation is slowing down and that millions of years ago there was a point in time where there was only a mere 20 hours in a day on Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is in two parts.  Firstly why is the Earth's rotation slowing given that angular momentum is conserved, and secondly given that understanding, will the Earth either (a) stop rotating in the future, or (b) eventually begin rotating in the reverse direction to what it is now or will it (c) reach a constant rotational velocity in the same direction it is rotating now and why?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think the answer to the question will depend on whether the Earth's rotation is slowing at a decreasing rate or at a constant rate.&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorDisplayName="user12525" LastEditDate="2019-04-23T08:43:32.870" LastActivityDate="2021-01-28T04:30:04.250" Title="Will the Earth ever stop rotating?" Tags="|geophysics|planetary-science|earth-rotation|" AnswerCount="4" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="237" PostTypeId="2" ParentId="234" CreationDate="2014-04-16T23:47:29.943" Score="23" Body="&lt;p&gt;In a nutshell:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The instrument measures microwave radiances (after calibration)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;If we know the sea surface temperature, we can use radiances to calculate emissivity.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The emissivity at 1.4 GHz is itself a function of near-surface ocean salinity.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;However, in reality, it's more complicated, because there are other factors that come into the equation, such as surface roughness, which depends on wind.  Remote sensing problems are often underdetermined, and we need to make assumptions in order to retrieve the desired quantity.  Measuring ocean salinity from space is a classical &lt;a href=&quot;https://en.wikipedia.org/wiki/Inverse_problem&quot;&gt;inverse problem&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can find details in the highly cited paper:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Kerr, Yann H., Philippe Waldteufel, J-P. Wigneron, J. Martinuzzi, Jordi Font, and Michael Berger. &quot;Soil moisture retrieval from space: The Soil Moisture and Ocean Salinity (SMOS) mission.&quot; Geoscience and Remote Sensing, IEEE Transactions on 39, no. 8 (2001): 1729-1735. (&lt;a href=&quot;http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=942551&quot;&gt;weblink&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;which addresses both soil moisture and ocean salinity.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2014-04-29T15:09:47.567" LastActivityDate="2014-04-29T15:09:47.567" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="238" PostTypeId="1" AcceptedAnswerId="2151" CreationDate="2014-04-17T00:04:15.310" Score="21" ViewCount="4602" Body="&lt;p&gt;What is the process that creates a tropopause fold?  Do these features have any significant impact(s) on weather patterns or the atmosphere?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Aolhg.jpg&quot; alt=&quot;Cross Section of a Tropopause Fold&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="38" LastEditorUserId="38" LastEditDate="2014-04-17T23:59:19.423" LastActivityDate="2014-06-25T03:04:48.690" Title="How do tropopause folds form and do they have any impact on synoptic scale weather?" Tags="|meteorology|troposphere|stratosphere|synoptic|vorticity|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="239" PostTypeId="1" AcceptedAnswerId="285" CreationDate="2014-04-17T00:18:11.430" Score="88" ViewCount="39080" Body="&lt;p&gt;No known hurricane has ever crossed the equator.  Hurricanes require the Coriolis force to develop and generally form at least 5° away from the equator since the Coriolis force is zero there. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are the physics of the earth and tropical systems such that it is impossible for a hurricane to cross the equator after forming, or are the forces working against this occurring so strong that an equator crossing hurricane is an exceedingly rare event we may not witness in 1000+ years?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cECCC.png&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cECCC.png&quot; alt=&quot;Tracks and Intensity of All Tropical Storms&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="38" LastEditorUserId="5698" LastEditDate="2016-03-29T10:55:02.210" LastActivityDate="2019-08-08T09:10:03.527" Title="Impossible or improbable? Hurricane crossing the equator" Tags="|meteorology|coriolis|tropical-cyclone|equator|" AnswerCount="3" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="240" PostTypeId="1" AcceptedAnswerId="260" CreationDate="2014-04-17T00:37:50.327" Score="16" ViewCount="7439" Body="&lt;p&gt;The inner core of the Earth has an enormous temperature of around 4300 degrees Celsius.  Is this large inner core temperature an important factor contributing to the ideal temperature that is necessary to maintain life as we know it on the Earth's outer-crust and atmosphere, or is the temperature of the core quite irrelevant to the temperature on the Earth's crust?&#xA;&lt;img src=&quot;https://i.stack.imgur.com/UbOw1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="87" LastEditDate="2014-04-23T11:47:10.763" LastActivityDate="2023-09-10T17:21:08.747" Title="Is the Earth's hot inner core necessary for life?" Tags="|climate|temperature|core|" AnswerCount="6" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="241" PostTypeId="1" AcceptedAnswerId="283" CreationDate="2014-04-17T00:39:46.807" Score="11" ViewCount="8188" Body="&lt;p&gt;What are the key differences between warm and cold core cyclones?  What is an example of each?&lt;/p&gt;&#xA;" OwnerUserId="38" LastEditorUserId="81" LastEditDate="2014-04-18T10:42:31.307" LastActivityDate="2014-04-18T10:42:31.307" Title="What are the key differences between warm and cold core cyclones?" Tags="|meteorology|synoptic|cyclone|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="242" PostTypeId="2" ParentId="240" CreationDate="2014-04-17T00:45:27.993" Score="6" Body="&lt;p&gt;Yes and no. The Earth's hot inner core is one of many factors that contribute to the theory of &lt;a href=&quot;http://en.wikipedia.org/wiki/Rare_Earth_hypothesis#With_plate_tectonics&quot; rel=&quot;nofollow&quot;&gt;Rare Earth&lt;/a&gt; indirectly. Since the potential temperature difference is what drives mantle convection (well density, but density depends on both pressure and temperature), the cold lithosphere and the hot core are absolutely necessary for the development of complex life if you take Darwin's theory of evolution to be the primary driver of speciation. Though, I'm sure there are other environments where life can emerge (I'm hoping one day we will find methanogenic life on Titan, that would be cool).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As winwaed also mentioned, the hot inner core is surrounded by a chaotically convecting liquid core which produces the Earth's magnetic field, undoubtedly important to life. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Edit for further explanation on the link between evolution and the potential temperature difference between the core and lithosphere:&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While this goes a bit out of my expertise, the Theory of Evolution requires a diversity of environments in which random mutations naturally give a species an advantage over another. Plate tectonics enhances this diversity, by not only transporting land to different climates but also making new ones (arc volcanism).  Without the temperature difference between the core and the lithosphere, we would not have mantle convection, which is the fundamental driver of plate tectonics. So while the temperature of the core is not directly necessary for life, it has allowed for a much more diverse speciation on this planet. This, of course, has other implications (such as surviving catastrophic extinction) but those I feel are outside the scope of this question. &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="87" LastEditDate="2014-04-17T07:29:54.470" LastActivityDate="2014-04-17T07:29:54.470" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="243" PostTypeId="1" AcceptedAnswerId="249" CreationDate="2014-04-17T01:07:43.840" Score="8" ViewCount="999" Body="&lt;p&gt;Inspired by the question, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/57/what-causes-earthquakes&quot;&gt;How does one measure what causes earthquakes?&lt;/a&gt;, I'd like to know what causes another great geological phenomenon - volcanoes? &lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-04-23T06:14:53.230" Title="What causes a volcano?" Tags="|volcanology|" AnswerCount="1" CommentCount="2" ClosedDate="2014-04-20T01:16:02.177" ContentLicense="CC BY-SA 3.0" />
  <row Id="244" PostTypeId="1" AcceptedAnswerId="250" CreationDate="2014-04-17T01:12:30.767" Score="10" ViewCount="640" Body="&lt;p&gt;According to a documentary, &quot;&lt;a href=&quot;http://www.dailymotion.com/video/xngjuy_horizon-mega-tsunami-wave-of-destruction-www-pisothshow-com_shortfilms&quot;&gt;Mega Tsunami - A wave of destruction&lt;/a&gt;&quot;, most mega tsunamis are caused by landslides creating tsunamis 10 times the size as those caused by earthquakes. It was said that there is a volcano in the Canary islands that holds water in an enclosed basin, which heats up every time the volcano erupts. It was said that this basin will cause the surrounding lands to crack and produce a massive landslide that will lead to a tsunami reaching America with a height as tall as a 50 story building.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it true that this mega tsunami is inevitable or very likely to occur?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="543" LastEditDate="2017-02-28T05:34:14.067" LastActivityDate="2017-02-28T05:34:14.067" Title="Is it inevitable that a mega tsunami will hit America?" Tags="|tsunami|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="245" PostTypeId="1" AcceptedAnswerId="248" CreationDate="2014-04-17T01:32:37.253" Score="20" ViewCount="6155" Body="&lt;p&gt;I have heard that extreme storm events can be caused simply by a butterfly flapping its wings somewhere in a distant location.  Is it true that such a small disturbance in the air in one location can result in such a large catastrophic event in another separate location?  If so how can we know this is possible, and how is this even possible?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorDisplayName="user12525" LastEditDate="2019-04-20T18:08:40.133" LastActivityDate="2019-04-20T18:08:40.133" Title="Is it true that a butterfly flapping its wings can result in a tornado in a distant location?" Tags="|meteorology|atmosphere|climate-models|chaos|" AnswerCount="5" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="246" PostTypeId="1" AcceptedAnswerId="257" CreationDate="2014-04-17T01:41:11.453" Score="14" ViewCount="11725" Body="&lt;p&gt;Inspired by the movie, &quot;&lt;a href=&quot;http://www.imdb.com/title/tt0298814/&quot;&gt;The Core&lt;/a&gt;&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can we really travel through earth's core? I will provide 2 sub questions:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Is there any substance that can resist the heat of earth's core?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Between the crust and mantle, and the mantle and outer core is there any &quot;wall&quot; between them? And how hard is the wall (can we go through it)?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="132" LastEditorUserId="725" LastEditDate="2016-01-22T00:55:55.263" LastActivityDate="2017-03-08T19:50:17.893" Title="Can we really travel through earth's core?" Tags="|core|mantle|drilling|" AnswerCount="4" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="248" PostTypeId="2" ParentId="245" CreationDate="2014-04-17T02:36:34.193" Score="25" Body="&lt;p&gt;The butterfly is a colourful illustration of &lt;a href=&quot;https://en.wikipedia.org/wiki/Chaos_theory&quot; rel=&quot;noreferrer&quot;&gt;Chaos Theory&lt;/a&gt;, and the word butterfly came from the diagram of the state space (see below).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A system that is &lt;em&gt;chaotic&lt;/em&gt; is extremely sensitive on its initial value.  In principle, if you know &lt;em&gt;exactly&lt;/em&gt; how the state of the universe is now, you could calculate how it develops (but due to other reasons, it is &lt;em&gt;theoretically impossible&lt;/em&gt; to know the state exactly — but that's not the main point here).  The issue with a chaotic system is that a &lt;em&gt;very&lt;/em&gt; small change in the initial state can cause a &lt;em&gt;completely different&lt;/em&gt; outcome in the system (given enough time).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, suppose that we take the entire atmosphere and calculate the weather happening for the next 20 days; suppose for the moment that we actually &lt;em&gt;do&lt;/em&gt; know every bit.  Now, we repeat the calculation, but with one &lt;em&gt;tiny tiny&lt;/em&gt; bit that is different; such as a butterfly flapping its wings.  As the nature of a chaotic system is such that a &lt;em&gt;very small&lt;/em&gt; change in the initial value can cause a &lt;em&gt;very large&lt;/em&gt; change in the final state, the difference between these two initial systems may be that one gets a tornado, and the other doesn't.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this to say that the butterfly flapping its wings results in a tornado?  &lt;strong&gt;No, not really&lt;/strong&gt;.  It's just a matter of saying, but not really accurate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many systems are chaotic:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Try to drop a leave from a tree; it will never fall the same way twice.&lt;/li&gt;&#xA;&lt;li&gt;Hang a pendulum below another pendulum and track its motion:&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/wMghE.gif&quot; alt=&quot;Double pendulum&quot;&gt; &#xA;&lt;br /&gt;&lt;sup&gt;(Figure from Wikipedia)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Or &lt;a href=&quot;https://en.wikipedia.org/wiki/Run_Lola_Run&quot; rel=&quot;noreferrer&quot;&gt;try to help your boyfriend&lt;/a&gt; in what must be one of the loveliest illustrations of Chaos Theory ever.  Suppose you are running to catch the bus.  You keep sight of a butterfly, which delays you by a split second.  This split second causes you to miss the bus, which later crashes into a ravine, killing everyone on board.  Later in life, you go on to be a major political dictator starting World War III (&lt;em&gt;Note: this is not the plot of the linked movie, but my own morbid reinterpretation&lt;/em&gt;).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Tell me, did this butterfly cause World War III?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not really.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/NQiNn.png&quot; alt=&quot;Lorenz attractors&quot;&gt;&#xA;&lt;br /&gt;&lt;sup&gt;(Figure from Wikipedia)&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2014-05-06T14:15:47.040" LastActivityDate="2014-05-06T14:15:47.040" CommentCount="21" ContentLicense="CC BY-SA 3.0" />
  <row Id="249" PostTypeId="2" ParentId="243" CreationDate="2014-04-17T02:37:34.410" Score="14" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/3kQ2b.jpg&quot; alt=&quot;Examples of Volcanism&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most volcanism occurs at three major tectonic features: Subduction Zones, Rifting Centers (Like East Pacific Rise) and under hotspots. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will start with the most contentious, hotspots. The clearest example of hotspot volcanism is the island chain Hawaii. Underneath the island, there is a chaotic discontinuity caused by the boundary conditions at the core-mantle boundary. This causes highly viscous and hot mantle to upwell rapidly and push through the lithosphere, forming a volcano. The orgin of hotspots is not well known, and it is even a debate if they exist (they do, imo). Some papers worth looking at are by Paul Hall (BU) and Christopher Kincaid(URI), and maybe Dave Stegman (Scripps) who publish on melting caused by mantle plumes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a consequence of a subducting slab, at a distance in front of the trench, Arc Volcanoes form. The distance in front of the trench is often thought to be where the overriding plate is 100-120km higher than the suducting slab. The cold, oceanic plate plunges underneath the continental plate in the image above, adding water to the mantle. This water lowers the melting temperature (solidus) of the mantle inside the wedge of the subduction zone, causing  partial melting (4-6%). This melt, more viscous and buoyant than the solid mantle, floats to tho the top of the mantle and eventually penetrates the lithosphere and forms a volcano. This &lt;a href=&quot;https://earthscience.stackexchange.com/questions/144/why-is-there-a-line-of-volcanoes-along-the-northwest-coast-of-north-america?rq=1&quot;&gt;question&lt;/a&gt; is also relevant. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, at divergent plate boundaries, the process is fairly straight forward. A break in the lithosphere caused by rifting plates allows the pressurized mantle to flow towards the opening. This causes and abundance of hot, fertile mantle which can be melted.  This melted mantle creeps through the lithosphere and forms ocean floor volcanoes (sometimes called smokers). &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-04-17T02:37:34.410" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="250" PostTypeId="2" ParentId="244" CreationDate="2014-04-17T02:47:12.483" Score="10" Body="&lt;p&gt;As a lecturer I had during my undergraduate put it: if you draw your information from BBC/Discovery Channel documentaries, you will believe we could get a 100-million-people-killing disaster every week.  The collapse of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cumbre_Vieja#Future_threats&quot; rel=&quot;noreferrer&quot;&gt;Cumbre Vieja&lt;/a&gt; is but one of those perceived threats.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How do such documentaries get their info?  Scientists develop models, then run them.  Remember than &lt;a href=&quot;https://en.wikiquote.org/wiki/George_E._P._Box&quot; rel=&quot;noreferrer&quot;&gt;all models are wrong, but some are useful&lt;/a&gt;.  Using their models, they speculate that &lt;em&gt;if&lt;/em&gt; the substance of the mountain has a certain shape, and &lt;em&gt;if&lt;/em&gt; the volcano erupts in a certain way, and &lt;em&gt;if&lt;/em&gt; this causes a landslide in a particular way, with a couple of more &lt;em&gt;ifs&lt;/em&gt;, then they speculate that there &lt;em&gt;might&lt;/em&gt; be a huge tsuname destroying the eastern US.  Do they state this with certainty?  Absolutely not.  Do other scientists agree with them?  Not really.  Does Discovery channel care that it doesn't appear very likely?  No.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The already linked Wikipedia article &lt;a href=&quot;https://en.wikipedia.org/wiki/Cumbre_Vieja#Future_threats&quot; rel=&quot;noreferrer&quot;&gt;Cumbre Vieja#Future threats&lt;/a&gt; answers this particular one better than I can do.  Don't worry and sleep well ;-).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oh, and you must visit, it is spectacular!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/xzJLT.jpg&quot; alt=&quot;Cumbre Vieja coast&quot;&gt;&#xA;&lt;br /&gt;La Palma, 27 December 2012.  Certainly, the inhabitants of the shores of the Cumbre Vieja are more at risk than the inhabitants of the US east coast. (&lt;sub&gt;P.S. I'm cheating, this is actually some 15 km north of the dangerous part of the slope.  But still, if this mega-tsunami &lt;em&gt;does&lt;/em&gt; happen, I think the TV networks will forget about the poor islanders :(&lt;/sub&gt;)&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2014-04-17T02:52:55.217" LastActivityDate="2014-04-17T02:52:55.217" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="251" PostTypeId="1" AcceptedAnswerId="749" CreationDate="2014-04-17T03:38:33.260" Score="18" ViewCount="1103" Body="&lt;p&gt;A tropical cyclone is the generic term for a hurricane, typhoon, or tropical storm.  &lt;a href=&quot;http://en.wikipedia.org/wiki/Tropical_cyclone&quot; rel=&quot;noreferrer&quot;&gt;Tropical cyclones&lt;/a&gt; derive their energy from evaporation of water at the ocean surface which ultimately recondenses when it cools to the saturation point.  The rotation of a tropical cyclone is caused by the &lt;a href=&quot;http://en.wikipedia.org/wiki/Coriolis_effect&quot; rel=&quot;noreferrer&quot;&gt;Coriolis effect&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is unclear to me is: &lt;strong&gt;Why do these massive bodies of warm, moist air clump together over thousands of kilometers?&lt;/strong&gt;  What physical process causes them to be drawn in towards the center of the storm?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/cGc1i.jpg&quot; alt=&quot;enter image description here&quot;&gt;&#xA;*image taken from the Wikipedia article on &lt;a href=&quot;http://en.wikipedia.org/wiki/Tropical_cyclone&quot; rel=&quot;noreferrer&quot;&gt;tropical cyclones&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="53" LastEditorUserId="140" LastEditDate="2014-05-21T20:30:59.783" LastActivityDate="2014-05-21T21:35:00.300" Title="Why do tropical cyclones not tear themselves apart?" Tags="|meteorology|weather|tropical-cyclone|vorticity|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="252" PostTypeId="2" ParentId="34" CreationDate="2014-04-17T03:48:34.283" Score="12" Body="&lt;p&gt;It seems like you are asking about proxies that are useful on the scale of tens to hundreds of millions of years. We have great proxies that going back thousands of years (tree rings, peat cores, lake sediments), and quite a few that go back around a million or so (speleothem, ice cores), but beyond that the data is in sediments and rocks.&lt;/p&gt;&#xA;&lt;p&gt;Deep sea sediment cores are probably the most important source of proxy material going back tens of millions of years, and carbonates the most useful lithology for retrieving proxy data from those cores. Changing CO2 values affect the PH of the ocean, and this has various effects on the plankton fossils and carbonate chemistry. One effect is that the &lt;a href=&quot;http://www.ldeo.columbia.edu/%7Edmcgee/Carbon/Syllabus_files/Hemming%20&amp;amp;%20Ho%CC%88nisch%202007.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;chemical speciation of boron in their shells will be affected&lt;/a&gt;. High CO2 dissolves in the ocean as carbonic acid, acidifying the water and causing there to be more B(OH)3 relative to B(OH)4. B(OH)3 is relatively more likely to form with the heavy isotope of Boron, Boron-11. Several other isotope systems can be used in similar ways. For example, carbon and oxygen isotopes (d13C, d18O) of foraminifera fossils have also been used to reconstruct atmospheric CO2. The processes determining these values are complex and involve ocean PH and partial pressures of dissolved gasses. The concentration of a chemical called alkenones in photosynthetic plankton is one of the more recently invented deep-sea core proxies for CO2 as well.&lt;/p&gt;&#xA;&lt;p&gt;One of the non-isotope proxies for CO2 dating back tens of millions of years is the &lt;a href=&quot;http://dx.doi.org/10.1016/j.quascirev.2013.02.003&quot; rel=&quot;nofollow noreferrer&quot;&gt;stomatal index record&lt;/a&gt;. Stomata are microscopic &amp;quot;mouths&amp;quot; on plant leaves that open and close to let in CO2 but keep H2O from escaping. In a higher CO2 environment, plants grow more stomata per unit area. Stomata can be counted in some plant fossils, and this can be used as a proxy.&lt;/p&gt;&#xA;&lt;p&gt;Most of the proxies are too complex to be modelled backwards to get the atmospheric CO2 values that caused them, so they must be calibrated against more &amp;quot;absolute&amp;quot; records such as bubbles in ice cores.&lt;/p&gt;&#xA;" OwnerUserId="63" LastEditorUserId="18081" LastEditDate="2021-09-28T12:10:57.507" LastActivityDate="2021-09-28T12:10:57.507" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="253" PostTypeId="2" ParentId="233" CreationDate="2014-04-17T05:02:52.707" Score="14" Body="&lt;p&gt;The bulk of the planet's precipitation falls from convective storms that develop throughout the Intertropical Convergence Zone (ITCZ). The ITCZ transits north and south of the equator due tracking the sun's zenith throughout the year and is skewed by the position of land, but is generally situated near the equator over the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/1tBJA.png&quot; alt=&quot;Wikipedia ITCZ&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/EWxEk.png&quot; alt=&quot;Global Precipitation&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://acd.ucar.edu/~lsmith/GEWEX-JHydroMet8.pdf&quot; rel=&quot;noreferrer&quot;&gt;Trenberth et al (2006)&lt;/a&gt; go into detail describing the different components of the global hydrological cycle, but the core of their research can be summed up in the image below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/4OoEj.png&quot; alt=&quot;Hydrologic Cycle from Trenberth et all (2006)&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;~96.5% of the world's water is held in the oceans.&lt;/li&gt;&#xA;&lt;li&gt;~90% of evaporated ocean water leads to precipitation over the oceans.&lt;/li&gt;&#xA;&lt;li&gt;~77% of precipitation falls over the ocean.&lt;/li&gt;&#xA;&lt;li&gt;~10% of evaporated ocean water leads to precipitation over land. This equals the roughly ~10% of runoff that returns to the oceans.&lt;/li&gt;&#xA;&lt;li&gt;Envirotranspiration from plants plays a noticeable role in the water cycle over land.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Personally, I do wonder about the ~77% falling over the ocean.  That number seems a slight bit low given recent remote sensing data of global annual precipitation.&lt;/p&gt;&#xA;" OwnerUserId="38" LastEditorUserId="38" LastEditDate="2014-04-17T05:15:40.120" LastActivityDate="2014-04-17T05:15:40.120" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="254" PostTypeId="2" ParentId="236" CreationDate="2014-04-17T05:10:19.023" Score="18" Body="&lt;p&gt;The short answer is &quot;Probably Yes&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The longer answer is that it is debatable whether Earth's rotation will become tidally locked to the moon due to tidal drag, at which point it will not be rotating &lt;em&gt;relative to the moon&lt;/em&gt;, or whether the sun's exhaustion of hydrogen and the fusion of Helium will result in the sun's expansion vaporizing the earth first.  As tidal drag slows the earth's rotation, the moon moves further away, reducing its effect on the earth's rotation, and making the calculations fairly complex.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In either case, unless something really unexpected happens to the earth first, such as it being ejected from the solar system, which is completely improbable, it &lt;em&gt;will&lt;/em&gt; stop rotating, if only due to it ceasing to be a planet at all.&lt;/p&gt;&#xA;" OwnerUserId="133" LastActivityDate="2014-04-17T05:10:19.023" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="255" PostTypeId="1" AcceptedAnswerId="313" CreationDate="2014-04-17T05:37:54.567" Score="23" ViewCount="543" Body="&lt;p&gt;Among the people I interact with in the geodynamics community, it seems that almost all of us are in full support of the mantle plume theory. What are the strongest arguments against this theory? Is the earth science community not as divided on this subject as some people have led me to believe ?&lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="28050" LastEditDate="2015-04-13T18:54:41.473" LastActivityDate="2015-04-19T16:19:43.193" Title="What are some of the strongest theories against the existence of mantle plumes?" Tags="|geophysics|volcanology|plate-tectonics|geodynamics|mantle-plumes|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="256" PostTypeId="2" ParentId="143" CreationDate="2014-04-17T05:49:12.970" Score="6" Body="&lt;p&gt;&lt;em&gt;Joe Kington has provided an excellent answer re sensing from space.&#xA;Torbjørn T. pointed out in a comment that the site that I linked for context actually has a good explanation... so after blushing slightly, I shall summarise it here. People with more specialist knowledge are, of course, welcome to elaborate or correct any misunderstanding.&#xA;Incidentally, it came as a surprise to me to realise that the land-based and space-based methods are entirely different techniques - so perhaps this should have been two questions.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's a good explanation at &lt;a href=&quot;http://www.codar.com/intro_hf_radar.shtml&quot;&gt;http://www.codar.com/intro_hf_radar.shtml&lt;/a&gt;.&#xA;In summary:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The surface of the sea, complete with waves, acts in a manner analogous to a diffraction grating. When illuminated with HF radar, only a specific frequency is returned in the direction of the transmitter, and that specific frequency corresponds to waves of a particular wavelength that are travelling directly towards or away from the transmitter.&#xA;This wavelength is one that is always present in the ocean (and, presumably, always present at some level in every direction of travel?).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming deep water, because we know the wavelength and frequency of the wave, we can calculate its speed. We can also obtain its speed from doppler shift in the radar return.&#xA;Any difference between the two must be due to surface currents.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2014-04-17T05:49:12.970" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="257" PostTypeId="2" ParentId="246" CreationDate="2014-04-17T06:20:41.757" Score="32" Body="&lt;p&gt;As Chris Mueller said, in short: it isn't, or at least highly infeasible. Projects to drill into the mantle, such as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole&quot;&gt;Kola Superdeep Borehole&lt;/a&gt;, have all failed because drilling equipment can't withstand the heat at only ~15km deep. Even if we were to come up with some sort of cooling system that's able to cool to 6400km or 12800km deep (depending on whether you would drill from one side only or from both sides at the same time), pressure is the second barrier that holds us from traveling through the earth's core. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to Lide (2006) the pressure in the inner core is 330 to 360 GPa, at which iron becomes a solid even at the high temperatures in the core. If you could drill as far as the core you would have to build a device that's able to withstand that pressure, because if you can't, the material surrounding your well would immediately become liquid and fill the hole, if not shoot up your well towards the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are no physical walls between the layers of the Earth, only transition zones where temperature and pressure combinations lead to different behaviour of the materials. An example is the Mohorovičić discontinuity, or Moho, which is the boundary between crust and mantle, below which temperatures are high enough and at the same time the pressure is low enough so that rock becomes either liquid or at least a &quot;flowing&quot; solid. Similarly, at the boundary between the inner and outer core the pressure is so high that even at those temperatures the iron becomes a solid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lide, D.R., ed. (2006-2007). &lt;a href=&quot;http://hbcpnetbase.com/&quot;&gt;&lt;em&gt;CRC Handbook of Chemistry and Physics&lt;/em&gt;&lt;/a&gt; (87th ed.). pp. j14–13.&lt;/p&gt;&#xA;" OwnerUserId="79" LastEditorUserId="79" LastEditDate="2014-04-22T20:41:08.723" LastActivityDate="2014-04-22T20:41:08.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="258" PostTypeId="1" CreationDate="2014-04-17T06:50:49.870" Score="10" ViewCount="58037" Body="&lt;p&gt;So, there are three main methods of transferring heat: radiation, convection/mass transfer, and conduction. Presumably radiation is not a major method of heat transport between the core and the crust, because it requires transparent materials (or a vacuum), and I don't think there is much of either in the mantle. Presumably conduction is the only significant method of transport in the crust, apart from volcanos.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, in the mantle, between the core, where heat is generated, and the crust, where it is eventually dissapated, what proportion of heat is transported via convection and conduction?&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="-1" LastEditDate="2014-09-24T19:04:50.410" LastActivityDate="2016-01-22T15:50:34.147" Title="How is heat transferred from the core through the mantle to the crust?" Tags="|geothermal-heat|mantle|" AnswerCount="3" CommentCount="6" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="259" PostTypeId="2" ParentId="216" CreationDate="2014-04-17T07:10:12.230" Score="7" Body="&lt;p&gt;This is a big question: it essentially translates to ‘how do we do palaeomagnetism’? I will try to give a brief overview and links to more detailed explanations. I'm also going to focus on the ‘how’, and leave the ‘why’ to someone else (perhaps it would be best split out into a separate question?). To record the geomagnetic field, you need three things:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;A ferromagnetic mineral -- that is, one that can be magnetized like a compass needle.&lt;/li&gt;&#xA;&lt;li&gt;A situation where grains of this mineral can have their magnetization aligned with the earth's field.&lt;/li&gt;&#xA;&lt;li&gt;An event that locks the magnetization in place once it's aligned.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;There are a surprising number of ways that (2) and (3) can happen, but for this answer I'll just describe the two that tend to be most useful: thermal remanent magnetization (TRM) and depositional remanent magnetization (DRM).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thermal remanent magnetization is induced when a rock cools from a hot (often molten) state. Here, (2) occurs because, above a certain temperature called the &lt;em&gt;blocking temperature&lt;/em&gt;, the magnetization of a mineral is able to change freely to align itself with the earth's magnetic field. As the rock cools, it becomes harder for the magnetization to align, and eventually it is locked in place.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Depositional remanent magnetization occurs in sediments, and is induced when grains of a magnetic mineral fall through the water column and land on the sea floor (or lake bottom). While they are in the water column, the grains are free to move and align themselves with the geomagnetic field. Once on the bottom, they gradually become buried in more layers of sediment, fixing their original orientation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In principle, recovering the recorded field from a piece of rock is very simple: you record the rock's orientation, cut or drill it from its current situation, then measure its magnetic field in a laboratory magnetometer. In an ideal world, the field you measure would correspond to the Earth's magnetic field when the rock was formed. In practice, it's rarely that simple, and you might need to use heat treatment or alternating-field demagnetization to ‘peel off’ weaker magnetizations that have been layered on top of the original magnetization over the years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This answer is a gross simplification and glosses over a great deal of theory, practical detail, and possible complication. For more depth, I would direct you to two excellent textbooks which (thanks to the magnanimity of their authors) are freely available online:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tauxe, L., Banerjee, S. K., Butler, R. F. and van der Voo, R. (2014). &lt;em&gt;Essentials of Paleomagnetism&lt;/em&gt;, third web edition. &lt;a href=&quot;http://earthref.org/MAGIC/books/Tauxe/Essentials/&quot; rel=&quot;nofollow&quot;&gt;http://earthref.org/MAGIC/books/Tauxe/Essentials/&lt;/a&gt; (accessed 2014-04-17)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Butler, R. F., (2004). &lt;em&gt;Paleomagnetism: Magnetic Domains to Geologic Terranes&lt;/em&gt;. electronic edition. &lt;a href=&quot;http://www.geo.arizona.edu/Paleomag/book/&quot; rel=&quot;nofollow&quot;&gt;http://www.geo.arizona.edu/Paleomag/book/&lt;/a&gt; (accessed 2014-04-17)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tauxe et al. (2014) is more recent and more extensive; Butler (2004) is an electronic reprint of a 1992 book, but is still an excellent introductory work, and provides (to my mind) a slightly gentler introduction than Tauxe et al. (2014). (While many advances have been made since 1992, the basic theory and techniques have not changed.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are interested in the nitty gritty of how the techniques are actually applied, you might want to look at:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Richter, C., Acton, G., Endris, C. and Radsted, M. (2007). &lt;em&gt;Handbook for shipboard paleomagnetists&lt;/em&gt;. ODP Technical Note 34, Texas A&amp;amp;M University, College Station, Texas, USA: Ocean Drilling Program. &lt;a href=&quot;http://www-odp.tamu.edu/publications/tnotes/tn34/TNOTE_34.PDF&quot; rel=&quot;nofollow&quot;&gt;http://www-odp.tamu.edu/publications/tnotes/tn34/TNOTE_34.PDF&lt;/a&gt; (accessed 2014-04-17)&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2014-04-20T11:09:26.310" LastActivityDate="2014-04-20T11:09:26.310" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="260" PostTypeId="2" ParentId="240" CreationDate="2014-04-17T07:17:07.893" Score="13" Body="&lt;p&gt;Whether the high temperatures of the core is strictly necessary to maintain a habitable temperature at the surface I'm not sure, as the global temperatures are largely controlled by insolation and the greenhouse effect. The black-body radiation temperature of the Earth is about -18&amp;#8239;&amp;#176;C, and even a more realistic estimate of the surface temperature without an atmosphere is around 1&amp;#8239;&amp;#176;C [1]. That being said, it depends on what you define as life, if the Earth had no atmosphere the temperature would have been lower, but organisms would have adapted to that if they existed in the first place.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As Neo and winwaed also mentioned, the molten iron in the core does protect organisms against harmful radiation from the sun, by providing the Earth with a shielding magnetic field.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, the hot core and mantle most likely did influence the origin of life to begin with, as near hydrothermal vents in the ocean floor conditions might have been or are suitable for spontaneous reactions that lead to the formation of self-reproducing molecules [2]. Note this is not in the Darwinian sense Neo talks about (Darwin's book is called &lt;em&gt;On the Origin of &lt;strong&gt;Species&lt;/strong&gt;&lt;/em&gt;, not &lt;em&gt;On the Origin of Life&lt;/em&gt;), but in the microbiological and geological sense.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1] &lt;a href=&quot;https://en.wikipedia.org/wiki/Black-body_radiation#Temperature_of_Earth&quot;&gt;https://en.wikipedia.org/wiki/Black-body_radiation#Temperature_of_Earth&lt;/a&gt;&lt;br&gt;&#xA;[2] Martin, W., J. Baross, D. Kelley, M.J. Russell (2008) &lt;em&gt;&lt;a href=&quot;http://dx.doi.org/10.1038/nrmicro1991&quot;&gt;Hydrothermal vents and the origin of life&lt;/a&gt;&lt;/em&gt;. Nature&lt;/p&gt;&#xA;" OwnerUserId="79" LastActivityDate="2014-04-17T07:17:07.893" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="261" PostTypeId="2" ParentId="35" CreationDate="2014-04-17T08:37:55.140" Score="8" Body="&lt;p&gt;As Spießbürger also mentions in his answer sedimentation rates are local, and highly depend on sediment supply and accommodation room in the sedimentary basin. Global sedimentation rates are then just an average of all sedimentary basins, and are closely related to global erosion rates, although not necessarily the same depending on the time scales you look at, as dissolution of minerals doesn't directly lead to sedimentation, and eroded material can be trapped in for example a glacier for a substantial amount of time. The erosion rates then depend on the amount of erodable material (so topography, vegetation cover, etc.) and climate conditions providing some means of transport. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;All in all globally averaged sedimentation rates could be calculated, but are in the end such an indirect effect of wildly varying causes, while at the same time not providing much meaningful data, that it's probably not something worth investing much time in.&lt;/p&gt;&#xA;" OwnerUserId="79" LastActivityDate="2014-04-17T08:37:55.140" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="264" PostTypeId="1" AcceptedAnswerId="266" CreationDate="2014-04-17T09:04:01.810" Score="15" ViewCount="379" Body="&lt;p&gt;Most paleogeographic maps available (&lt;a href=&quot;http://www.scotese.com/Default.htm&quot;&gt;C. R. Scotese&lt;/a&gt; or &lt;a href=&quot;http://jan.ucc.nau.edu/rcb7/globaltext2.html&quot;&gt;R. Blakey&lt;/a&gt; maps for instance) show not only the shape of the continents during the concerned period but also the level of the seas and oceans (i. e. the coastlines, the epicontinental seas, etc.).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since &lt;a href=&quot;http://www.sciencemag.org/content/235/4793/1156.short&quot;&gt;Haq et al. 1987&lt;/a&gt;, there has been quite a few reconstructions of the &lt;em&gt;global relative sea level changes&lt;/em&gt; for parts of the Phanerozoic. But going from such global curves to actual maps showing the approximative coastlines and epicontinental seas does require a fair amount of extra information such as paleobathymetry of the oceans and paleoaltimetry of the continents to name the more obvious.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my question is: do we have such informations on a global scale? Or are the sea level representation on such maps just a shot in the dark?&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-04-17T09:23:55.123" LastActivityDate="2014-04-17T09:45:31.030" Title="Sea Level in Paleogeographic Maps" Tags="|paleogeography|sea-level|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="265" PostTypeId="1" AcceptedAnswerId="271" CreationDate="2014-04-17T09:13:14.730" Score="11" ViewCount="25761" Body="&lt;p&gt;What are the main differences between geologists and geophysicists?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="51" LastEditDate="2014-04-17T09:19:09.517" LastActivityDate="2022-10-26T10:17:37.367" Title="What is the difference between a geologist and a geophysicist?" Tags="|geophysics|geology|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="266" PostTypeId="2" ParentId="264" CreationDate="2014-04-17T09:28:03.740" Score="11" Body="&lt;p&gt;There are various plate tectonic models around, that are able to provide insight in paleobathymetry and -altimetry. These models include information on sea floor spreading and subduction, which provides much information on bathymetry. Also plate tectonic movement largely drives the uplift of mountain ranges, and combining this with isostatic effects of sediment loading, glaciation, etc. you can get a fair picture of paleoaltimetry as well. Of course this method provides only relatively low resolution data, and to get more detailed maps you need more localised data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Outcrops and bore holes provide much information on the depositional environment, and for example &lt;a href=&quot;https://en.wikipedia.org/wiki/Sequence_stratigraphy&quot;&gt;sequence stratigraphy&lt;/a&gt; is a tool that can be used to predict/retrodict regional environments. If you know from a number of locations where the coastline was relative to its current position, and know from models etc. where the sampling locations were in the past you can map paleocoastlines as well. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to answer your question shortly, yes there is a lot of global information available by combining large scale models and local investigations, and where such information is missing you can at least provide an educated guess of coastal positions.&lt;/p&gt;&#xA;" OwnerUserId="79" LastEditorUserId="79" LastEditDate="2014-04-17T09:45:31.030" LastActivityDate="2014-04-17T09:45:31.030" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="267" PostTypeId="1" AcceptedAnswerId="270" CreationDate="2014-04-17T09:36:32.767" Score="16" ViewCount="330" Body="&lt;p&gt;In most or all geological site reports I read, the groundwater table (of the uppermost groundwater layer) always followed the morphology of the surface. Is this always the case? Are there signs for situation where this might not be the case, something I can see on the surface?&lt;/p&gt;&#xA;" OwnerUserId="117" LastEditorUserId="56" LastEditDate="2014-04-18T01:24:17.527" LastActivityDate="2014-05-13T23:32:45.367" Title="Are there situations where the groundwater table doesn't follow the morphology of the surface?" Tags="|geology|hydrology|water-table|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="268" PostTypeId="2" ParentId="41" CreationDate="2014-04-17T09:45:44.187" Score="6" Body="&lt;p&gt;Plant matter decomposes, partly it is digested aerobically (releasing CO2 again) but partly it forms &lt;a href=&quot;http://en.wikipedia.org/wiki/Humic_acid&quot;&gt;humic acids&lt;/a&gt;. The latter are a large part of topsoil. In this form, carbon can be sequestered in the ground for a long time.  &lt;/p&gt;&#xA;" OwnerUserId="117" LastActivityDate="2014-04-17T09:45:44.187" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="269" PostTypeId="2" ParentId="246" CreationDate="2014-04-17T09:51:00.800" Score="21" Body="&lt;p&gt;Short answer: No.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Long answer: Our deepest drills failed around &lt;a href=&quot;http://www.atlasobscura.com/places/kola-superdeep-borehole&quot;&gt;12km down when the drill bits were having to cope with temperatures hot enough to melt the drills&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;12km down is only a tiny distance into the earth.  The average distance to the center is over &lt;a href=&quot;http://www.universetoday.com/48919/distance-to-the-center-of-the-earth/&quot;&gt;6300km&lt;/a&gt;.   So didn't even get to half of a percent of the way to the center.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To do so, we'd have to have:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;a vehicle capable of propulsion through liquid magma&lt;/li&gt;&#xA;&lt;li&gt;capable of drilling through various types of very thick rock&lt;/li&gt;&#xA;&lt;li&gt;capable of surviving temperatures over &lt;a href=&quot;http://en.wikipedia.org/wiki/Inner_core#Temperature_and_pressure&quot;&gt;5400 degrees Celsius&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;capable of surviving pressures of over &lt;a href=&quot;http://en.wikipedia.org/wiki/Inner_core#Temperature_and_pressure&quot;&gt;330 gigapascals&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;capable of insulating passengers and their atmosphere within the vehicle from the extreme temperatures outside&lt;/li&gt;&#xA;&lt;li&gt;capable of doing this in a reasonable time (ie days - given you'd need oxygen and food and water for the passengers)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;none of which are currently possible.&lt;/p&gt;&#xA;" OwnerUserId="73" LastActivityDate="2014-04-17T09:51:00.800" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="270" PostTypeId="2" ParentId="267" CreationDate="2014-04-17T10:57:30.060" Score="13" Body="&lt;p&gt;The groundwater table depends on a lot of properties. These include precipitation rates, permeability/transmissivity of the subsurface and regional groundwater flow. There are two different regimes that are distinguished: one with a &lt;em&gt;topography-controlled watertable&lt;/em&gt; and the other with a &lt;em&gt;recharge-controlled watertable&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A topography-controlled watertable closely follows local topography, while a recharge-controlled watertable only follows the regional topography, and so 'following the morphology' is partly scale dependent. To give an estimate of which regime is more likely at a location, Haitjema and Mitchell-Bruker (2005) studied a number of models and came to the following equation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\frac{\overline{R}_r}{K} \cdot &#xA;\frac{\overline{L}}{\overline{D}} \cdot &#xA;\frac{\overline{L}}{z_{\text{max}}} &#xA;\left\{ &#xA; \begin{array}{ll}&#xA; &amp;gt; m &amp;amp; \text{topography controlled} \\&#xA; &amp;lt; m &amp;amp; \text{recharge controlled}&#xA; \end{array}&#xA;\right.&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where the terms have the following meaning:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$R_r$ is the average anual recharge rate&lt;/li&gt;&#xA;&lt;li&gt;$K$ is the aquifer's hydraulic conductivity&lt;/li&gt;&#xA;&lt;li&gt;$L$ is the average distance between surface waters&lt;/li&gt;&#xA;&lt;li&gt;$D$ is the average aquifer thickness&lt;/li&gt;&#xA;&lt;li&gt;$z_{\text{max}}$ is the maximum distance between the surface water levels and terrain elevation&lt;/li&gt;&#xA;&lt;li&gt;$m$ is either 8 for one dimensional groundwater flow, or 16 for radial-symmetric groundwater flow (in a circular aquifer).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In cases of a relatively low permeability combined with enough recharge by precipitation the groundwater is likely to follow the surface. However, for example in karst areas, where extensive networks of caves and tunnels in soluble rock cause a very effective drainage over long distances, the groundwater will follow the surface on a much more regional scale. Also, areas with high relief groundwater at least isn't parallel to the surface, and for example in sand dunes, the groundwater level is usually relatively flat compared to the dune.&lt;/p&gt;&#xA;" OwnerUserId="79" LastEditorUserId="67" LastEditDate="2014-05-13T23:32:45.367" LastActivityDate="2014-05-13T23:32:45.367" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="271" PostTypeId="2" ParentId="265" CreationDate="2014-04-17T11:00:50.550" Score="12" Body="&lt;p&gt;First of all you have to think about that both geology and geophysics are huge fields and even people that think of themselves as a geologist or geophysicist can have vastly different research topics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a geologist and a geophysicist are interested in the same topic, e.g. the lithosphere, they will have a lot in common. In this example I think the main differences would be methodology. While a geophysicist would rely on the analysis of seismic waves, numerical simulations and modelling, a geologists would work more with lithospheric scale cross sections, and geologic data that he or she can gather on the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In summary I would say: The fields have much overlap, many differences, and when approaching a question more calculations and modelling will be done in geophysics and more field work and lab work (petrology, age dating, stratigraphic age, ...) will be done in geology.&lt;/p&gt;&#xA;" OwnerUserId="23" LastActivityDate="2014-04-17T11:00:50.550" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="272" PostTypeId="1" AcceptedAnswerId="2805" CreationDate="2014-04-17T11:09:06.883" Score="10" ViewCount="112" Body="&lt;p&gt;&lt;strong&gt;Bohrmann et al. 1989&lt;/strong&gt; advanced the idea that the silicate phase from some clinoptilolites come from the diagenetic degradation of biogenic opal (from radiolarians in that case but presumably also other siliceous microfossils).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this hypothesis is still regarded as valid, is clinoptilolite the only kind of authigenic zeolite that can be traced to biogenic opal?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has any work been done in that domain since this paper?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;&lt;sub&gt;Source:&lt;br&gt;&#xA;Bohrmann, G., Stein, R., Faugères, J.-C., 1989. &lt;a href=&quot;http://dx.doi.org/10.1007/BF01829322&quot; rel=&quot;nofollow&quot;&gt;Authigenic  zeolites  and their  relation  to  silica  diagenesis  in ODP  Site  661 sediments  (Leg  108,  Eastern Equatorial  Atlantic)&lt;/a&gt;. Geologische Rundschau, 78(3): 779-792.&#xA;&lt;/sub&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-07-10T07:13:00.710" LastActivityDate="2014-11-15T14:27:10.067" Title="Biogenic origin of authigenic zeolites" Tags="|paleontology|sedimentology|diagenesis|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="273" PostTypeId="2" ParentId="240" CreationDate="2014-04-17T11:20:51.480" Score="5" Body="&lt;p&gt;The liquid outer core and the magnetic field it generates are essential to life. Without the magnetic field we would have no atmosphere. The temperatures would be roughly equal to the moon (Which goes from 123 C on the hemisphere that happens to face the sun and -153 C on the shadowed hemisphere).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source for moon temperatures:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.space.com/18175-moon-temperature.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.space.com/18175-moon-temperature.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="23" LastActivityDate="2014-04-17T11:20:51.480" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="274" PostTypeId="2" ParentId="258" CreationDate="2014-04-17T11:27:50.637" Score="11" Body="&lt;p&gt;It is still a little known fact that radiation play an important role in the Earth's mantle. Experiments show that mantle-material becomes transparent to infrared radiation at increasing pressures (&lt;a href=&quot;http://www.esrf.eu/news/general-old/general-2004/earthbadro/index_html&quot;&gt;http://www.esrf.eu/news/general-old/general-2004/earthbadro/index_html&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would also say that the mantle is currently not understood in a way where estimates of heat-conduction-type versus depth can be accurately made. The heterogeneity of heat transfer (Cold detached subduction-slabs sinking to various depths and hot plumes quickly rising from the D''-layer) makes the question even more difficult.&lt;/p&gt;&#xA;" OwnerUserId="23" LastActivityDate="2014-04-17T11:27:50.637" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="275" PostTypeId="1" CreationDate="2014-04-17T12:06:17.447" Score="13" ViewCount="216" Body="&lt;p&gt;This has always bothered me during field mapping: A boudin with two stretching directions has the form of an M&amp;amp;M candy (or almond shape). What do I do to measure the two stretching directions if the surrounding rocks don't show any stretching lineations. Does anybody have experience with this?&lt;/p&gt;&#xA;" OwnerUserId="23" LastEditorUserId="94" LastEditDate="2016-04-13T06:38:00.523" LastActivityDate="2016-04-13T06:38:00.523" Title="How to measure stretching direction on chocolate-tablet boudins?" Tags="|structural-geology|mapping|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="276" PostTypeId="2" ParentId="258" CreationDate="2014-04-17T12:22:44.160" Score="3" Body="&lt;p&gt;Conduction probably is the main method in the crust, but do not underestimate fluid convection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Every time you find a hot spring, then that is an example of fluid convection. Even volcanic eruptions could be considered convection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Possibly even larger than these too, there is vigorous convection of seawater through young ocean crust. This can be seen on &lt;a href=&quot;http://www.auscope.org.au/userfiles/file/Communications/Muller_etal_age_rate_asym_G3_2008-1.pdf&quot; rel=&quot;nofollow&quot;&gt;Figure 10 of Muller eta al Digital Models of the World's Ocean Crust&lt;/a&gt;.  This plots depth vs age of ocean curve.  The &quot;TBL&quot; line approximates the curve that is expected for conductive cooling of the Earth's crust. Reality (the bars) are rather different. Although most of this cooling is in young rock, the accumulative effect shows in the older crust. (this plot is trying to demonstrate something else, but I couldn't find a good example of this classic graph that implied this convection must exist long before Black Smokers were ever discovered)&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2014-04-17T12:22:44.160" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="277" PostTypeId="1" AcceptedAnswerId="661" CreationDate="2014-04-17T12:43:46.317" Score="18" ViewCount="162" Body="&lt;p&gt;&lt;strong&gt;Lawver &amp;amp; Gahagan (1998; 2003)&lt;/strong&gt; hypothesized, based on sea level records and the isostatically adjusted bedrock surface of Antarctica, the existence of a Trans-Antarctic Seaway linking the Ross Sea and the Weddell Sea, between the Antarctic peninsula and the Ellsworth Mountains, in the Paleogene.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has any other evidence confirming or infirming the existence of such a seaway been found since then? If so, do we have an idea of when it opened and closed?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;&lt;sub&gt;Source:&lt;br&gt;&#xA;Lawver, L. A., Gahagan, L. M., 1998. Opening of Drake Passage and and its impact on Cenozoic ocean circulation. In Crowley, T. C. &amp;amp; Burke, K. C., &lt;a href=&quot;http://books.google.de/books?id=HbamVUkDTLMC&amp;amp;printsec=frontcover#v=onepage&amp;amp;q&amp;amp;f=false&quot;&gt;Tectonic boundary conditions for climate reconstructions&lt;/a&gt;, Oxford monographs on geology and geophysics, 39: 212-227.&lt;br&gt;&#xA;Lawver, L. A., Gahagan, L. M., 2003. &lt;a href=&quot;http://dx.doi.org/10.1016/S0031-0182(03)00392-4&quot;&gt;Evolution of Cenozoic seaways in the circum-Antarctic region&lt;/a&gt;. Palaeogeography, Palaeoclimatology, Palaeoecology, 198: 11-37.&#xA;&lt;/sub&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-10-01T12:21:43.470" LastActivityDate="2014-10-01T12:21:43.470" Title="Paleogene transantarctic seaway" Tags="|oceanography|sea-level|antarctic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="279" PostTypeId="2" ParentId="201" CreationDate="2014-04-17T13:29:21.727" Score="6" Body="&lt;p&gt;This is an interesting question and I feel the best answer is &quot;a little bit of both&quot;.  Consider your picture without the overshooting top and just the anvil.  The tropopause is clearly defined as the anvil spreads out horizontally against the static stability of the stratosphere.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now let us consider a single parcel in the updraft, accelerating upward due to &lt;a href=&quot;https://en.wikipedia.org/wiki/Convective_available_potential_energy&quot; rel=&quot;nofollow&quot;&gt;CAPE&lt;/a&gt; and hitting the tropopause with significant vertical momentum.  This parcel is full of tropospheric air but makes an excursion into the stratosphere until the negative buoyancy it experiences reduces its vertical velocity to 0 (the top of the overshooting top) and then continues to accelerate downward to eventually oscillate about its equilibrium level (level of neutral buoyancy).  For this single parcel I would argue that it is in the stratosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now consider all of the updraft parcels doing this.  They are all transporting tropospheric air upward into the stratosphere -- inside that cloud it is all tropospheric air and toward the edges it is a mix of tropospheric and stratospheric air due to entrainment.  The tropospheric air transported upward that mixes with the stratospheric air will reduce the static stability locally and may eventually modify the temperature gradient such that you consider the tropopause lifted.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I may run a simulation later with many grid levels around the tropopause and see what a model has to say.  I'll edit with my results.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="6" LastEditDate="2014-04-17T14:43:24.733" LastActivityDate="2014-04-17T14:43:24.733" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="280" PostTypeId="1" CreationDate="2014-04-17T13:30:13.037" Score="5" ViewCount="237" Body="&lt;p&gt;The &lt;a href=&quot;http://en.wikipedia.org/wiki/Grand_Canyon&quot; rel=&quot;nofollow noreferrer&quot;&gt;Grand Canyon&lt;/a&gt; is nearly 446 km (300 miles) long, 29 km (18 miles) wide, and over 1,8 km (1 mile) deep. To the best of my knowledge, there is no other canyon of comparable size in the world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this in fact the case? If no, which canyons are larger? If yes, what made the Grand Canyon so much larger than others? What is, perhaps, a &quot;fusion&quot; of several other, smaller canyons linked by the Colorado River? Were the rock formations surrounding the Grand Canyon in some ways more &quot;continuous&quot; than others in the world? Were there at one time other canyons of comparable size elsewhere in the world that somehow got broken up into smaller entities?&lt;/p&gt;&#xA;" OwnerUserId="42" LastEditorUserId="42" LastEditDate="2019-06-23T15:52:07.527" LastActivityDate="2019-06-23T15:52:07.527" Title="Is the Grand Canyon the &quot;greatest&quot; canyon in the world?" Tags="|geology|geomorphology|erosion|" AnswerCount="0" CommentCount="7" ClosedDate="2014-04-19T15:12:23.843" ContentLicense="CC BY-SA 4.0" />
  <row Id="281" PostTypeId="1" AcceptedAnswerId="282" CreationDate="2014-04-17T13:41:11.277" Score="16" ViewCount="20946" Body="&lt;p&gt;What differences are there between  geology, petrology, and lithology?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I were to get into any of those fields, what exactly would I be studying?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, are petrology and lithology just branches of geology?&lt;/p&gt;&#xA;" OwnerUserId="115" LastEditorUserId="115" LastEditDate="2014-04-18T01:01:35.217" LastActivityDate="2017-02-03T09:13:58.900" Title="What are the differences between geology, petrology, and lithology?" Tags="|geology|petrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="282" PostTypeId="2" ParentId="281" CreationDate="2014-04-17T14:10:47.573" Score="19" Body="&lt;p&gt;The basic differences are:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Geology&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;study of rocks and minerals: the study of the structure of the Earth or another planet, especially its rocks, soil, and minerals, and its history and origins&lt;/li&gt;&#xA;&lt;li&gt;structure of area: the rocks, minerals, and physical structure of a specific area&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Petrology&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;study of rocks: the study of sedimentary, igneous, and metamorphic rocks with respect to their occurrence, structure, origin, history, and mineral content &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Lithology&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;description of the physical characteristics of a rock unit or rock formation, and actually not a scientific discipline as the two above&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="116" LastEditorUserId="725" LastEditDate="2014-11-29T11:36:59.930" LastActivityDate="2014-11-29T11:36:59.930" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="283" PostTypeId="2" ParentId="241" CreationDate="2014-04-17T14:19:58.210" Score="6" Body="&lt;p&gt;Key differences are in structure, location, environments they thrive in.  To compare/contrast these storms I'll use a mid-latitude cyclone for the cold core cyclone and a hurricane for the warm core cyclone.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Structure&lt;/p&gt;&#xA;&lt;p&gt;The hurricane is nearly symmetric and devoid of fronts.  The mid-latitude cyclone is asymmetric (comma shaped with a long tail) and has fronts associated with it.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Location and Movement&lt;/p&gt;&#xA;&lt;p&gt;Hurricanes form in the tropics (but not around the Equator) and initially move from east to west with a discrete well-defined low pressure center.  Hurricanes move with the wind.  Mid-latitude cyclones occur in the mid-latitudes and move west to east with centers of low pressure that may dissipate and re-form further downstream.  Mid-latitude storms move as temperature advection drives pressure falls ahead of the storm.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Environment&lt;/p&gt;&#xA;&lt;p&gt;Hurricanes need warm ocean surface and weak vertical wind shear throughout the troposphere to develop.  Mid-latitude storms are at home with shear and require horizontal temperature gradients to develop.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Hurricanes can transition into cold-core cyclones once they exit the tropics.  It is possible, but not common, for a mid-latitude cyclone to transition into a warm-core tropical cyclone.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-04-17T16:03:58.103" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="284" PostTypeId="1" AcceptedAnswerId="290" CreationDate="2014-04-17T14:49:04.717" Score="22" ViewCount="152" Body="&lt;p&gt;Seismic surface waves present a characteristic dispersion behavior in which different frequencies travel at different speeds. This characteristic &lt;em&gt;dispersion curve&lt;/em&gt; depends on the shear and compressional wave velocity structure of the crust and upper mantle. These physical parameters can be estimated using some inversion method that can be 1D, 2D, or even 3D. 1D inversions are very common for their relative simplicity and speed. However, the dispersion is usually measured &lt;strong&gt;between two stations&lt;/strong&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my question is, where do we &quot;place&quot; the resulting 1D estimated model? Is it the average of the crust between the stations (I did the math for this once long ago and it seems that it is not, but I'm not sure)? Or is there no way to place the estimate at a single point?&lt;/p&gt;&#xA;" OwnerUserId="137" LastEditorUserId="192" LastEditDate="2015-03-20T17:12:03.877" LastActivityDate="2015-03-20T17:12:03.877" Title="Placement of crustal thickness estimation from 1D inversion of surface wave dispersion curves" Tags="|seismology|waves|inversion|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="285" PostTypeId="2" ParentId="239" CreationDate="2014-04-17T15:09:38.597" Score="71" Body="&lt;p&gt;Improbable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is well known that the Coriolis force is needed to form a hurricane, and the figure of 5&lt;sup&gt;o&lt;/sup&gt;N/S as the minimum for formation is widely publicized. You can also find record of tropical storm formation near India as far south as 1.4&lt;sup&gt;o&lt;/sup&gt;N.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem of crossing the Equator isn't one of hurricane formation though, it is one of hurricane motion.  Due to Coriolis, a hurricane initially moving parallel to the Equator will start gaining a poleward component to its motion, thus moving it away from the Equator.  But, because this is due to Coriolis, if you could get a storm close enough to the Equator, this effect would not be as strong.  This would be an improbable track, but I'm not willing to call it impossible.  We haven't had satellites all that long, and all we can really say is that it hasn't happened since we've been watching.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a storm did cross the equator though, what would it do?  Nothing at first, but as it moved further into the opposite hemisphere, Coriolis would be working against the storm and it would spin down, become disorganized and cease to be a hurricane, probably becoming a remnant low.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A tropical disturbance &lt;em&gt;has&lt;/em&gt; crossed the equator.  One such disturbance occurred June 27, 2008 in the Atlantic basin (south to north) that retained its clockwise motion for some time:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.imgur.com/YbTLvTr.gif&quot; alt=&quot;animated satellite loop&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="5698" LastEditDate="2016-03-29T13:44:04.137" LastActivityDate="2016-03-29T13:44:04.137" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="286" PostTypeId="1" AcceptedAnswerId="16489" CreationDate="2014-04-17T15:38:05.980" Score="30" ViewCount="2113" Body="&lt;p&gt;While reading the &lt;a href=&quot;http://en.wikipedia.org/wiki/Pyroclastic_flow&quot;&gt;Wikipedia article on pyroclastic flows&lt;/a&gt;, I noticed that there's a section called &lt;a href=&quot;http://en.wikipedia.org/wiki/Pyroclastic_flow#Interaction_with_water&quot;&gt;'Interaction with water'&lt;/a&gt;. This piqued my interest, as I was under the impression that lava generally doesn't interact much with water other than cooling down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To my surprise, this claim is made in the article:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Testimonial evidence from the 1883 eruption of Krakatoa, supported by experimental evidence, shows that pyroclastic flows can cross significant bodies of water. One flow reached the Sumatran coast as much as 48 km (30 mi) away.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I tried to look up the citations, but they're both in books that I don't have access to at the moment. Can these flows cross water, and how?&lt;/p&gt;&#xA;" OwnerDisplayName="user13" LastEditorUserId="56" LastEditDate="2014-04-22T23:48:16.110" LastActivityDate="2019-03-18T19:37:47.957" Title="Can pyroclastic flows cross water?" Tags="|volcanoes|pyroclastic-flows|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="287" PostTypeId="1" CreationDate="2014-04-17T15:43:30.790" Score="4" ViewCount="253" Body="&lt;p&gt;I think we can all agree that these are hills:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/LvbRs.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;Image from &lt;a href=&quot;http://en.wikipedia.org/wiki/File:Chocolate_Hills.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They're kinda gentle, not too tall, and altogether nice-looking. But it's always bugged me that I can't come up with an objective definition for the word. Is that little bump in my lawn a hill? It's gentle, not too tall, and altogether nice looking. But I still wouldn't call it a hill.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a widely accepted definition for 'hill'?&lt;/p&gt;&#xA;" OwnerDisplayName="user13" LastEditorDisplayName="user13" LastEditDate="2014-04-17T17:08:13.083" LastActivityDate="2014-04-17T17:08:13.083" Title="Is there a standard definition of a hill?" Tags="|terminology|" AnswerCount="0" CommentCount="5" ClosedDate="2014-04-18T19:40:41.077" ContentLicense="CC BY-SA 3.0" />
  <row Id="288" PostTypeId="2" ParentId="286" CreationDate="2014-04-17T15:57:42.010" Score="12" Body="&lt;p&gt;Can't help with the details, but think about it like this. It is a density current (denser than air, that's why it flows downhill), but the density is less than that of water, so it will flow across it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Compare this to turbidity flows (also density currents), which are denser than water and will therefore flow downhill in the ocean.&lt;/p&gt;&#xA;" OwnerUserId="23" LastActivityDate="2014-04-17T15:57:42.010" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="289" PostTypeId="2" ParentId="286" CreationDate="2014-04-17T16:06:30.653" Score="16" Body="&lt;p&gt;In answer to the title question, &quot;yes&quot;!&#xA;Here are some videos from Montserrat Soufriere Hills where the phenomenon has been extensively studied (probably more than anywhere else):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.geo.mtu.edu/volcanoes/west.indies/soufriere/govt/images/051296/&quot;&gt;http://www.geo.mtu.edu/volcanoes/west.indies/soufriere/govt/images/051296/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As well as Krakatoa, Mt Pelee's (Martinique) 1902 eruption managed to ignite ships in the harbour when the main town was destroyed - which suggests the pyroclastic flows crossed the harbour.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also my u/g mapping area in North Wales included the Snowdon Volcanic Group. It and related tuffs appear to have been erupted over water and/or wet estuary type environments (there is open to debate).&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2014-04-17T16:06:30.653" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="290" PostTypeId="2" ParentId="284" CreationDate="2014-04-17T16:15:59.657" Score="12" Body="&lt;p&gt;This is a very good question, not just important to seismic inversion, but also modeling in general. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lets set this problem up differently. Lets say point's A and D are nodes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/C6kkc.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each node represents a system of equations, and these equations are only calculated on these points. Therefore, the model can only exist on the points in which they are calculated. Since B and C are dimensionally  between A and D, a smoothing factor must be imposed to graphically represent them. So while there might be a line in between A and D, the model only exists on points A and D. To find the model at point B and C, you would have to build them in your model, creating a higher resolution mesh.  This is perhaps why it is so important to have a dense seismic array when doing seismic studies. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in your case, the model is dependent on information on information at two stations, making each node &lt;strong&gt;TWO STATIONS&lt;/strong&gt;. This would mean that the it is impossible to give an exact geographic location to where the inversion is, just a generalized idea of between these two stations. &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="32" LastEditDate="2014-04-17T16:24:20.127" LastActivityDate="2014-04-17T16:24:20.127" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="291" PostTypeId="1" AcceptedAnswerId="623" CreationDate="2014-04-17T17:19:46.720" Score="10" ViewCount="125" Body="&lt;p&gt;Is there a page where I can look up rock unit definitions for France similar to:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.bgs.ac.uk/lexicon/home.cfm&quot;&gt;https://www.bgs.ac.uk/lexicon/home.cfm&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.bgr.de/app/litholex/index.php&quot;&gt;http://www.bgr.de/app/litholex/index.php&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I did some searching for this, but because of my poor French I couldn't find anything.&lt;/p&gt;&#xA;" OwnerUserId="23" LastEditorUserId="81" LastEditDate="2014-04-18T10:42:27.057" LastActivityDate="2014-04-30T15:22:21.837" Title="Is there a database of the geologic/stratigraphic units of France?" Tags="|regional-geology|stratigraphy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="292" PostTypeId="1" CreationDate="2014-04-17T17:28:22.243" Score="12" ViewCount="516" Body="&lt;p&gt;What are the likely stresses that caused the uplift of the Harz mountains? Was the uplift connected to another orogeny, lithospheric-scale folding or a mantle process?&lt;/p&gt;&#xA;" OwnerUserId="23" LastActivityDate="2014-05-01T13:06:56.110" Title="What caused the Cretaceous uplift of the Harz mountains (Germany)" Tags="|regional-geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="293" PostTypeId="1" AcceptedAnswerId="386" CreationDate="2014-04-17T17:32:52.863" Score="5" ViewCount="615" Body="&lt;p&gt;More and more evidence of fossilized dinosaurs with feathers are appearing. Did many dinosaurs have feathers and did this change during the Mesozoic?&lt;/p&gt;&#xA;" OwnerUserId="23" LastEditorUserId="42" LastEditDate="2014-04-20T23:06:33.043" LastActivityDate="2014-11-20T13:29:48.103" Title="Were dinosaurs with feathers common?" Tags="|paleontology|" AnswerCount="1" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="295" PostTypeId="1" AcceptedAnswerId="440" CreationDate="2014-04-17T18:37:17.763" Score="20" ViewCount="441" Body="&lt;p&gt;The models I have in mind are the major global models such as the Global Forecast System (GFS) and the European Center for Medium range Weather Forecasting (ECMWF).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These models produce numerous output and as such there are numerous ways to validate the forecast they produce. I've seen many plots that focus on specific heights on the 500 mb surface to gauge forecast accuracy, but that is all I'm familiar with. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How is model skill and forecast correctness measured?  Is it an overall global skill, or are various skills in specific regions of the globe also evaluated?  Are these validation results freely available on the internet?&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="124" LastEditDate="2014-04-29T13:18:31.213" LastActivityDate="2016-09-11T03:14:34.587" Title="How is global weather model skill measured?" Tags="|meteorology|models|nwp|validation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="296" PostTypeId="2" ParentId="286" CreationDate="2014-04-17T19:37:18.667" Score="8" Body="&lt;p&gt;I think I recall that being superheated, the pyroclastic flow can cross water as it can ride over a layer of steam generated from the water surface, sort of like a hovercraft, but riding on steam rather than blown air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also Lava/volcanoes do interact with water, aside from the relatively benign interaction with basaltic pillow lavas (which I assume is the cooling you speak of) there are &lt;a href=&quot;https://en.wikipedia.org/wiki/Phreatic_eruption&quot;&gt;https://en.wikipedia.org/wiki/Phreatic_eruption&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="140" LastEditorUserId="140" LastEditDate="2014-04-17T20:25:40.797" LastActivityDate="2014-04-17T20:25:40.797" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="298" PostTypeId="5" CreationDate="2014-04-17T21:17:56.377" Score="0" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The study of the physics, chemistry, and dynamics of the earth's atmosphere, including the related effects at the air–earth boundary over both land and the oceans. Fundamental topics include the composition, structure, and motion of the atmosphere. The goals ascribed to meteorology are the complete understanding and accurate prediction of atmospheric phenomena.  -- &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Meteorology&quot; rel=&quot;nofollow&quot;&gt;Glossary of Meteorology, American Meteorological Society&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="64" LastEditorUserId="20" LastEditDate="2014-08-17T22:56:46.560" LastActivityDate="2014-08-17T22:56:46.560" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="299" PostTypeId="4" CreationDate="2014-04-17T21:17:56.377" Score="0" Body="The study of how the earth's atmosphere works, including weather forecasting. Use this tag for questions about the earth's weather. When asking questions specifically about the atmosphere, also include the [atmosphere] tag." OwnerUserId="-1" LastEditorUserId="6298" LastEditDate="2019-02-06T03:06:19.243" LastActivityDate="2019-02-06T03:06:19.243" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="300" PostTypeId="1" AcceptedAnswerId="307" CreationDate="2014-04-17T21:22:22.210" Score="16" ViewCount="6458" Body="&lt;p&gt;I know that geostrophic flow means straight wind flow that is balanced by the pressure gradient and Coriolis forces. But what do quasi-geostrophic and ageostrophic mean specifically?&lt;/p&gt;&#xA;" OwnerDisplayName="anon" LastEditorUserId="124" LastEditDate="2014-04-18T17:31:09.370" LastActivityDate="2019-05-19T13:15:59.663" Title="What do quasi-geostrophic and ageostrophic mean?" Tags="|meteorology|coriolis|wind|dynamics|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="301" PostTypeId="5" CreationDate="2014-04-17T21:44:41.437" Score="0" Body="&lt;p&gt;The atmosphere is the gaseous outer layer of a planet.  For the Earth (and other inner planets), it is characterised by a sharp lower boundary, separating it from the &lt;a href=&quot;/questions/tagged/ocean&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged &amp;#39;ocean&amp;#39;&quot; rel=&quot;tag&quot;&gt;ocean&lt;/a&gt;, the &lt;a href=&quot;/questions/tagged/cryosphere&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged &amp;#39;cryosphere&amp;#39;&quot; rel=&quot;tag&quot;&gt;cryosphere&lt;/a&gt;, or land surface.  The atmosphere is a highly dynamical system due to differential heating, effects of the rotating Earth, transport of latent and sensible heat, and other effects.  For more information:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere&quot; rel=&quot;nofollow&quot;&gt;Wikipedia article Atmosphere&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Earth&quot; rel=&quot;nofollow&quot;&gt;Wikipedia article Atmosphere of Earth&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2014-04-19T22:25:42.393" LastActivityDate="2014-04-19T22:25:42.393" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="302" PostTypeId="4" CreationDate="2014-04-17T21:44:41.437" Score="0" Body="The gaseous envelope surrounding the *Earth*, and retained by the Earth's gravitational field. If your question is about the atmosphere on another celestial body or is more astronomy related, please ask on Astronomy.SE." OwnerUserId="115" LastEditorUserId="6298" LastEditDate="2019-02-06T03:15:11.347" LastActivityDate="2019-02-06T03:15:11.347" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="303" PostTypeId="5" CreationDate="2014-04-17T22:04:36.213" Score="0" Body="&lt;p&gt;A tsunami is a series of waves that occur right after the displacement of a large amount of water. Some examples of this are an earthquake, a volcanic eruption, or an underwater explosion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tsunamis were first discovered as early as 462 BC. &lt;a href=&quot;http://www.perseus.tufts.edu/hopper/text?doc=Thuc.%203.89.1&amp;amp;redirect=true&quot; rel=&quot;nofollow&quot;&gt;Greek historian Thucydides inquired in his book &lt;em&gt;History of the Peloponnesian War&lt;/em&gt; about the cause of tsunamis&lt;/a&gt;, and thought that an earthquake might be the cause:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The cause of such inundation, for my part, I take to be this: that the&#xA;  earthquake, where it was very great, did there send off the sea; and&#xA;  the sea returning on a sudden, caused the water to come on with&#xA;  greater violence. And it seemeth unto me that without an earthquake&#xA;  such an accident could never happen.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Some notable recent tsunamis are: &lt;a href=&quot;http://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami&quot; rel=&quot;nofollow&quot;&gt;the 2011 Japan tsunami&lt;/a&gt;, &lt;a href=&quot;http://en.wikipedia.org/wiki/2004_Indian_Ocean_earthquake&quot; rel=&quot;nofollow&quot;&gt;the 2004 Indian Ocean tsunami&lt;/a&gt;, and &lt;a href=&quot;http://en.wikipedia.org/wiki/Megatsunami#1980%3a_Spirit_Lake.2C_Washington.2C_USA&quot; rel=&quot;nofollow&quot;&gt;the 1980 Spirit Lake &quot;megatsunami&quot;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20" LastEditorUserId="20" LastEditDate="2014-04-19T22:25:55.680" LastActivityDate="2014-04-19T22:25:55.680" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="304" PostTypeId="4" CreationDate="2014-04-17T22:04:36.213" Score="0" Body="A tsunami is a series of waves that occur right after the displacement of a large amount of water. Use this tag for questions about tsunamis, why they happen, and how they occur." OwnerUserId="20" LastEditorUserId="20" LastEditDate="2014-04-19T22:25:02.423" LastActivityDate="2014-04-19T22:25:02.423" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="305" PostTypeId="1" AcceptedAnswerId="309" CreationDate="2014-04-17T22:33:55.723" Score="23" ViewCount="2544" Body="&lt;p&gt;Why is 'positive' lightning rarer, brighter, higher charged, and longer lasting than 'negative' lightning?  Are there any other unique characteristics to positive lightning that sets it apart from more common negative lightning?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Positive Lightning vs Negative Lightning&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Rarity: 1:10 - 1:20 (on average)&lt;/li&gt;&#xA;&lt;li&gt;Charge: 10:1 (on average)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;(I'd imagine that brightness and duration are correlated to the charge).&lt;/p&gt;&#xA;" OwnerUserId="38" LastEditorUserId="38" LastEditDate="2014-04-17T22:54:33.467" LastActivityDate="2015-03-02T01:07:57.463" Title="What causes 'positive' lightning to be rarer, higher charged, and longer lasting than 'negative' lightning?" Tags="|meteorology|convection|lightning|electromagnetism|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="306" PostTypeId="2" ParentId="41" CreationDate="2014-04-17T22:45:58.240" Score="10" Body="&lt;p&gt;One way to lock some of the carbon in plant biomass into the soil for a very long time is, paradoxically, by burning it.  While most of the carbon in burning vegetation does literally go up in smoke, turning back into CO&lt;sub&gt;2&lt;/sub&gt;, a small fraction &amp;mdash; around 1% to 5% or so &amp;mdash; of it turns into ash and charcoal, collectively known as &lt;strong&gt;black carbon&lt;/strong&gt; or pyrogenic carbon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once formed, this black carbon can stay in the soil for a very long time (half-life measured in thousands of years) since, being essentially inorganic elemental carbon, it is not easily broken down by microorganisms.  Some of it can also get transported by air and/or rivers into lakes and seas, where it can become locked up in sediments for even longer times.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For instance, to quote Forbes, Raison &amp;amp; Skjemstad, &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0048969706004475&quot;&gt;&quot;Formation, transformation and transport of black carbon&#xA;(charcoal) in terrestrial and aquatic ecosystems&quot;&lt;/a&gt;, &lt;em&gt;Science of the Total Environment&lt;/em&gt; 370 (2006), pp. 190–206 (&lt;a href=&quot;http://www.researchgate.net/publication/6926438_Formation_transformation_and_transport_of_black_carbon_%28charcoal%29_in_terrestrial_and_aquatic_ecosystems/file/e0b4952971b42bd4ac.pdf&quot;&gt;PDF&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;BC [= black carbon] can comprise up to 40% of the OC [= organic carbon] in terrestrial soils and between 12% and 31% of the OC in deep ocean sediments, and has radiocarbon ages in soils in excess of thousands of years. Hence, BC appears to have a significant half-life, in the order of thousands of years. This relative inertness means that the projected &amp;lt;3% of the carbon converted to BC during forest, savanna and grassland fires, must be considered a significant component of the global carbon cycle with a very slow turnover.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In recent years, there's been increasing interest in the deliberate conversion of biomass into black carbon, often known as &lt;a href=&quot;//en.wikipedia.org/wiki/Biochar&quot;&gt;&lt;strong&gt;biochar&lt;/strong&gt;&lt;/a&gt; in this context.  Such artificial charring can achieve much higher conversion ratios than natural burning, on the order of 50% or so, while simultanenously allowing the rest of the biomass to be converted e.g. into biogas and/or directly into energy.  The resulting biochar can then e.g. be mixed into farm soil (where it can apparently improve water retention and pH and otherwise improve the soil quality), or it could potentially be dumped into the ocean for very long-term storage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All this makes biochar production a very attractive proposition.  It's almost an environmental engineer's dream come true &amp;mdash; a power plant / biogas generator with a &lt;em&gt;negative&lt;/em&gt; net CO&lt;sub&gt;2&lt;/sub&gt; emission rate, effectively burning the hydrogen in hydrocarbon biofuel for energy while locking down the carbon into an inert form that &amp;mdash; as icing on the cake &amp;mdash; can then be sold as soil improvement material.  Of course, as usual with emerging technologies, it's not entirely free of practical problems, but it does show promise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ps. Of course, there are also other mechanisms by which carbon in biomass can become locked down for long periods.  For example, in &lt;a href=&quot;//en.wikipedia.org/wiki/Peat_bog&quot;&gt;peat bogs&lt;/a&gt;, the dead moss and other vegetation does not decay normally due to the low pH and lack of oxygen, but rather accumulates as peat.  This can also sequester the carbon in it for thousands of years &amp;mdash; assuming, of course, that no pesky humans come along to &lt;a href=&quot;http://en.wikipedia.org/wiki/Peat#Characteristics_and_uses&quot;&gt;dig it up and burn it&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="142" LastActivityDate="2014-04-17T22:45:58.240" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="307" PostTypeId="2" ParentId="300" CreationDate="2014-04-17T22:48:11.887" Score="13" Body="&lt;p&gt;Ageostrophic winds are merely the component of the actual wind that is not geostrophic.  In other words, given the actual wind ($\mathbf v$) and the geostrophic wind ($\mathbf v_g$), the ageostrophic wind ($\mathbf v_a$) is the vector difference between them.  The ageostrophic wind represents friction and and other effects.  This, for example, is responsible for surface wind crossing isobars rather than following them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\mathbf v_a =\mathbf v - \mathbf v_g$$&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Quasigeostrophic refers to a modified set of equations that are make a number of assumptions, approximations and neglecting terms due to scaling.  The equations are only valid for Rossby numbers much less than 1 (Ro &amp;lt;&amp;lt; 1)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some of these include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;neglect advection by $\mathbf v_a$&lt;/li&gt;&#xA;&lt;li&gt;neglect advection by vertical velocity&lt;/li&gt;&#xA;&lt;li&gt;neglect the time tendency of $\mathbf v_a$&lt;/li&gt;&#xA;&lt;li&gt;neglect advection of $\mathbf v_a$ by $\mathbf v_g$&lt;/li&gt;&#xA;&lt;li&gt;replace $f$ with the beta plane approximation ($f = f_0 + \beta y$)&lt;/li&gt;&#xA;&lt;li&gt;neglect friction&lt;/li&gt;&#xA;&lt;li&gt;horizontally constant static stability ($\sigma$)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Starting with the frictionless horizontal momentum equations you end up with a number of &quot;Q-G&quot; equations: a thermodynamic energy equation, a vorticity equation and the omega equation.  The Q-G omega equation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\left( \nabla^2_p + \dfrac{f^2_0}{\sigma}\dfrac{\partial^2}{\partial p^2} \right)\omega =  - \dfrac{f_0}{\sigma} \dfrac{\partial}{\partial p} \left[ - \mathbf v_g \cdot \mathbf \nabla_p(\zeta_g + f) \right] + \dfrac{R}{\sigma p}\left[ -\nabla^2_p(- \mathbf v_g \cdot \mathbf \nabla_p T) \right]$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first term on the RHS vertical change in advection of geostrophic absolute vorticity by the geostrophic wind.  Positive vorticity advection increasing with height results in upward vertical motion.  Negative vorticity advection increasing with height results in downward vertical motion. The second term on the RHS is related to temperature advection by the geostrophic wind.  Cool air advection (CAA) correlates with upward vertical motion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the traditional form of the equation and other forms exist to aid in diagnosing vertical motion with specific variables (e.g. the Sutcliffe-Trenberth recasts the equation using the thermal wind and Hoskins et al. (1978) defines the equation in terms of $\vec Q$, &quot;Q vectors&quot;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There isn't much NWP utility to the Q-G equations with todays computers, but they are good for diagnosing vertical motion in hand map analysis.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(will add the QG chi equation here)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further reading:  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.mmm.ucar.edu/people/tomjr/files/realtime/diagnostics.html&quot;&gt;Real-time anlyses and forecasts of the QG diagnostic equations&lt;/a&gt; &lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.geos.ed.ac.uk/~rharwood/teaching/phys4/dynamics/ch_13.pdf&quot;&gt;The QG equations&lt;/a&gt; (Thanks @DrewP84)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Quasi-geostrophic_equations&quot;&gt;An abbreviated derivation&lt;/a&gt; &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2014-04-24T14:35:16.243" LastActivityDate="2014-04-24T14:35:16.243" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="308" PostTypeId="1" AcceptedAnswerId="2648" CreationDate="2014-04-17T23:22:35.283" Score="8" ViewCount="6736" Body="&lt;p&gt;The Caledonian mountains and Appalachian mountains are recognised to be the roots of the same Palaeozoic orogenic belt. This has since been split in two with the opening of the Atlantic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the European side, two orogenies are recognised: the Caledonian and Variscan (or Hercynian). On the American side the Appalachians are also recognised to be made up of multiple orogenies, eg. the Taconic and Allegheny.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A parallel could be drawn with the present day Tethyan Belt - especially the Mediterranean length. Here we don't see one big mountain building episode but many as each sub-continent or large island is accreted onto Europe. Similarly, Pangaea was not formed in one big orogeny but multiple as sub-continents such as Avalonia were accreted on to what is now North America.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can each orogenic episode on the European side be correlated with an orogenic episode on the North American side? I.e. having two names for the same orogeny?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are correlations possible at a finer scale? For example the Caledonides in Scotland are marked by some very prominent ancient faults (Great Glen, Moine, and Highland Boundary Faults). The Appalachians also have some large fault systems. Can any of these be correlated across the Atlantic?&#xA;Can specific sedimentary sequences be correlated?&#xA;(I realise that big picture sequences in the late Palaeozoic are broadly similar, e.g. Permian Aeolian Sandstones, Carboniferous Deltaics &amp;amp; Coal, etc)&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2014-10-17T20:27:43.940" Title="Correlating the Caledonian and Appalachian Orogenies" Tags="|orogeny|correlation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="309" PostTypeId="2" ParentId="305" CreationDate="2014-04-17T23:29:38.707" Score="11" Body="&lt;p&gt;Positive lightning is indeed very interesting. &lt;a href=&quot;http://www.srh.noaa.gov/jetstream/lightning/positive.htm&quot; rel=&quot;noreferrer&quot;&gt;According to the National Weather Service&lt;/a&gt;, the reason why it has a higher amperage and voltage is due to the due to the amount of air it must get through to reach the ground. Otherwise, it would never reach the ground.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Since it originates in the upper levels of a storm, &lt;strong&gt;the amount of air&#xA;  it must burn through to reach the ground usually much greater.&#xA;  Therefore, its electric field typically is much stronger than a&#xA;  negative strike.&lt;/strong&gt; Its flash duration is longer, and its peak charge and&#xA;  potential can be ten times greater than a negative strike; as much as&#xA;  300,000 amperes and one billion volts!&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This would also account for the brightness of positive lightning and the extended duration, as a higher amperage &amp;amp; voltage strike would appear brighter and take longer to dissipate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://diaxiomtechnologies.com/what-creates-positive-lightning&quot; rel=&quot;noreferrer&quot;&gt;This page&lt;/a&gt; talks about why positive lightning occurs. It says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Positive lightning&quot; is a simple process of completing an electrical&#xA;  circuit from the cloud to the ground and back to the cloud.  &lt;strong&gt;As&#xA;  negative lightning strikes the ground, the ground becomes negatively&#xA;  charged over a wide area.  As the storm moves over this area and past&#xA;  it, the H+ in the upper reaches of the cloud feels this potential&#xA;  difference from the ground and sends out a positive streamer which,&#xA;  for all intents, looks like normal negative lightning.  The ground&#xA;  sends up a negative streamer and once these two join, electrons from&#xA;  the ground flow upwards to the H+ in the top of the cloud. The ground&#xA;  then becomes neutral once again.  The ground will hold the negative&#xA;  charge of dozens of negative strikes, building up a huge potential,&#xA;  before positive lightning will occur.&lt;/strong&gt;   This is why positive lightning&#xA;  is so powerful.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/zCVLj.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Positive lightning is probably so rare because it takes so many negative strikes in order for enough energy to build up to cause a positive lightening strike.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are quite a few interesting facts about positive lightning:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Some interesting properties of positive lightning:&lt;/p&gt;&#xA;  &#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;&lt;p&gt;Positive lightning can be the dominate type of cloud-to-ground during the winter months and in the dissipating stage of a&#xA;  thunderstorm.&lt;/p&gt;&lt;/li&gt;&#xA;  &lt;li&gt;&lt;p&gt;Positive lightning has been identified as a major source for the recently discovered sprites and elves. Sprites and elves are most&#xA;  likely lightning discharges but occur from 18-60 miles (30-95 km) in&#xA;  altitude, well above the parent thunderstorm.&lt;/p&gt;&lt;/li&gt;&#xA;  &lt;li&gt;&lt;p&gt;Positive lightning is usually composed of one stroke (negative lightning typically consists of two or more strokes)&lt;/p&gt;&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nssl.noaa.gov/education/svrwx101/lightning/faq/&quot; rel=&quot;noreferrer&quot;&gt;Another NOAA site says&lt;/a&gt; that positive lightning can strike &quot;near the edge of a cloud&quot;, or even 10 miles away from the cloud! This means that a positive lighting strike &lt;em&gt;could&lt;/em&gt; occur somewhere where the sky is blue, and it's not raining.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition, there is also a type of lightning called &quot;bipolar&quot; lightning, which &lt;em&gt;changes&lt;/em&gt; its polarity.&lt;/p&gt;&#xA;" OwnerUserId="20" LastEditorUserId="20" LastEditDate="2015-03-02T01:07:57.463" LastActivityDate="2015-03-02T01:07:57.463" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="310" PostTypeId="1" AcceptedAnswerId="2762" CreationDate="2014-04-17T23:42:57.933" Score="20" ViewCount="1957" Body="&lt;p&gt;'Rare earths' play a vital role in the modern economy, and they are becoming more of a point of focus in geopolitical realms.  What are 'rare earths' and why do they appear to cluster in association with:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;alkaline to peralkaline igneous complexes&lt;/li&gt;&#xA;&lt;li&gt;pegmatites associated with alkaline magmas/carbonatite intrusives&lt;/li&gt;&#xA;&lt;li&gt;perovskite mineral phases within akaline complexes&lt;/li&gt;&#xA;&lt;li&gt;mantle derived carbonate melts&lt;/li&gt;&#xA;&lt;li&gt;hydrothermal deposits associated with alkaline magmatism&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/bpDrW.jpg&quot; alt=&quot;Rare Earths&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="38" LastEditorUserId="725" LastEditDate="2014-11-13T06:51:50.363" LastActivityDate="2016-10-05T14:16:52.707" Title="What are rare earths and why do they cluster near alkaline magmatism?" Tags="|geology|geochemistry|economic-geology|rare-earth|magmatism|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="311" PostTypeId="2" ParentId="310" CreationDate="2014-04-18T00:54:47.850" Score="12" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Rare_earth_element&quot;&gt;&quot;Rare earth&quot;&lt;/a&gt; metals consist of Scandium, Yttrium, and 15 other metals of the so-called &quot;Lanthanide&quot; series toward the bottom of the &lt;a href=&quot;http://en.wikipedia.org/wiki/Periodic_table&quot;&gt;Periodic Table&lt;/a&gt; of elements. Basically, these are the chemicals that we &lt;strong&gt;didn't&lt;/strong&gt; study in chemistry class at school.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Like other metals, they have two electrons in the outer shell, but unlike &quot;metallic&quot; chemicals such as sodium or magnesium, they have a special &quot;metal&quot; shell for electrons. They are located at the &quot;left&quot; (relative to the carbon family) or akaline end of the Periodic Table, which is why they are found near alkaline magnatism, in alkaline &quot;compounds.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is in contrast to the more common chemicals, which are typically found as &quot;oxides,&quot; or &quot;sulfides,&quot; or possibly in combination with fluorine or chlorine. These common chemical compounds are on the right, or acid side of the periodic table.&lt;/p&gt;&#xA;" OwnerUserId="42" LastEditorUserId="42" LastEditDate="2014-04-18T01:01:10.693" LastActivityDate="2014-04-18T01:01:10.693" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="312" PostTypeId="2" ParentId="85" CreationDate="2014-04-18T01:34:07.343" Score="7" Body="&lt;p&gt;Your question uses the word &quot;likely&quot;, so to that I would say no, it's not likely, but it can happen, depending on the tectonic setting and the state of the stress field.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In 2007 work on the &lt;a href=&quot;http://www.geothermal.ch/index.php?id=94&amp;amp;L=1&quot;&gt;&quot;hot rock&quot; geothermal project in Basel, Switzerland&lt;/a&gt; was stopped because hydraulic stimulation caused a series of small seismic events that were over a predetermined safe level of magnitude. Most of the seismic events were too small to be felt at the surface, or even recorded on &quot;normal&quot; seismometers. The project was located in an active fault setting, and in the centre of a city, and though the seismic activity was at most about 3 ML (Richter scale), the project was deemed unsafe for the city's residents and buildings and eventually canned.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some large dams are known to cause minor seismic activity as they fill up, again depending on the tectonic setting. &lt;/p&gt;&#xA;" OwnerUserId="61" LastActivityDate="2014-04-18T01:34:07.343" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="313" PostTypeId="2" ParentId="255" CreationDate="2014-04-18T01:57:45.657" Score="20" Body="&lt;p&gt;The best argument I've heard supporting strong skepticism of plumes, if not total dismissal, is that the theory is too flexible. To put it more bluntly, this amounts to saying that it is unfalsifiable and therefore not helpful (in Popper's words, &quot;A theory that explains everything, explains nothing.&quot;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Erik Lundin, a Norwegian geologist, is a fairly vociferous (and sarcastic) proponent of this view. He likes to point out that you can explain almost any tectonic anomaly with plumes. Have a look at his articles &lt;a href=&quot;http://www.mantleplumes.org/Iceland2.html&quot;&gt;&lt;em&gt;The Iceland “Anomaly” – An Outcome of Plate Tectonics&lt;/em&gt;&lt;/a&gt; and &lt;a href=&quot;http://www.mantleplumes.org/Abstracts/Lundin_NGS_2004.html&quot;&gt;&lt;em&gt;Phanerozoic fold belts and volcanic passive margins: a causal relationship?&lt;/em&gt;&lt;/a&gt; on Gillian Foulger's site &lt;a href=&quot;http://www.mantleplumes.org/About.html&quot;&gt;mantleplumes.org&lt;/a&gt; — where you'll find lots of other evidence for and against plumes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My own view is that there seems to be some clear cases of plume-like things being a good explanation for observations — the Hawaiian–Emperor chain comes to mind. And then there's the rest of the infinitely complex earth, with thousands of competing and interacting forces, convection currents being just one.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2014-04-18T01:57:45.657" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="314" PostTypeId="2" ParentId="245" CreationDate="2014-04-18T03:03:18.257" Score="1" Body="&lt;p&gt;It's just a demonstration of cause-and-effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Over time(years and years) even the smallest motions compound, and the eddies from butterfies wings will be the difference between a tornado and a clear day.&lt;/p&gt;&#xA;" OwnerUserId="116" LastActivityDate="2014-04-18T03:03:18.257" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="315" PostTypeId="1" AcceptedAnswerId="327" CreationDate="2014-04-18T09:00:37.497" Score="13" ViewCount="640" Body="&lt;p&gt;Caesium-137 is &lt;a href=&quot;http://www.northerndailyleader.com.au/story/2223585/santos-issued-please-explain-over-radioactive-material-in-pilliga/?cs=159&quot;&gt;used in the fracking process&lt;/a&gt;. What is it used for?&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="725" LastEditDate="2016-01-22T00:56:20.913" LastActivityDate="2016-01-22T00:56:20.913" Title="What is caesium-137 used for in fracking?" Tags="|gas|resources|drilling|fracking|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="316" PostTypeId="1" AcceptedAnswerId="328" CreationDate="2014-04-18T09:29:58.497" Score="18" ViewCount="1633" Body="&lt;p&gt;I hope that the question title is resonably clear: What are the most significant factors which influence the tide height? I'm aware of the following couple of them:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Sun-Earth-Moon relative position (higher tide when co-linear)&lt;/li&gt;&#xA;&lt;li&gt;Size of the land/peninsula/island (higher for larger lands I suppose?)&lt;/li&gt;&#xA;&lt;li&gt;Shape of the surrounding seafloor (Hawaii has low tide partly because it has no shelf)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;However, I'm really curious as which are the most important amongst them? Or is it even possible to guess the tide height if I know the Lunar phase and I have a good globe with sea depth?&lt;/p&gt;&#xA;" OwnerUserId="99" LastEditorUserId="124" LastEditDate="2014-04-18T17:30:59.713" LastActivityDate="2014-04-20T22:29:16.097" Title="What influences tide-height the most? Can I guess the height by looking on a globe?" Tags="|ocean|oceanography|sea-level|tides|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="319" PostTypeId="1" CreationDate="2014-04-18T10:29:14.287" Score="20" ViewCount="1069" Body="&lt;p&gt;Many of the richest and purest iron ores are found in so called banded iron formations, cm thick magnetite or hematite layers intermixed with iron poor rock layers. Since these are usually of pre-Cambrian age, the processes involved seem to preclude modern day environments.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="725" LastEditDate="2014-11-13T06:52:43.570" LastActivityDate="2016-11-26T12:05:45.450" Title="How are the banded-iron-formation iron-ores formed?" Tags="|earth-history|geobiology|economic-geology|iron|precambrian|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="320" PostTypeId="1" AcceptedAnswerId="343" CreationDate="2014-04-18T11:14:50.123" Score="21" ViewCount="344" Body="&lt;p&gt;I am working with a coastal hydrodynamic model in the MIKE3 modelling package. MIKE3 uses the finite volume method to solve the shallow water equations with explicit timestepping, over a triangular mesh.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My model frequently &quot;blows up&quot; (numerically diverges) in a few cells around a headland, at times of peak flow. What steps can I take to improve the numerical stability, either through modifications to the mesh or other measures?&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="111" LastEditDate="2015-07-17T17:33:45.323" LastActivityDate="2015-07-17T17:33:45.323" Title="How can I improve the numerical stability of a coastal hydrodynamic model?" Tags="|oceanography|models|coastal|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="321" PostTypeId="1" AcceptedAnswerId="326" CreationDate="2014-04-18T12:35:26.470" Score="25" ViewCount="1940" Body="&lt;p&gt;Jet streams are fast-flowing currents of air in our earth's atmosphere. An enormous amount of energy is necessary to keep a jet stream going. Where does this come from and why?&lt;/p&gt;&#xA;" OwnerUserId="116" LastEditorUserId="116" LastEditDate="2014-05-01T14:26:54.757" LastActivityDate="2019-03-14T01:06:02.507" Title="What is the cause of the jet streams?" Tags="|atmosphere|weather|meteorology|jet-stream|air-currents|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="322" PostTypeId="1" AcceptedAnswerId="337" CreationDate="2014-04-18T12:44:36.540" Score="23" ViewCount="20995" Body="&lt;p&gt;Some crystals, like quartz and diamonds, form in a variety of different colors. For example, quartz can be clear, 'foggy', pink, yellow, and even blue.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;What happens during the crystal's formation to make it one color or&#xA;another?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="115" LastEditorUserId="725" LastEditDate="2016-05-10T09:39:44.653" LastActivityDate="2019-07-29T15:54:16.817" Title="Why do crystals, like quartz and diamonds, form in different colors?" Tags="|geology|crystals|crystallography|diamond|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="323" PostTypeId="2" ParentId="321" CreationDate="2014-04-18T12:54:21.640" Score="5" Body="&lt;p&gt;Jet streams are caused by a combination of a planet's rotation on its axis and atmospheric heating. These form air masses near each other of different temperatures, which cause jet streams.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, a links that might help you: &lt;a href=&quot;http://www.weatherquestions.com/What_causes_the_jet_stream.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;What causes the jet stream?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="115" LastEditorUserId="6093" LastEditDate="2016-12-08T08:36:53.933" LastActivityDate="2016-12-08T08:36:53.933" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="324" PostTypeId="1" AcceptedAnswerId="329" CreationDate="2014-04-18T13:01:03.397" Score="14" ViewCount="7246" Body="&lt;p&gt;How and where do double-terminated crystals form?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most terminated crystals form by 'growing' out of a rock. Which causes one side to be flat,(or whatever the shape of the rock it 'grew' out of was shaped like), and the other side to be 'terminated'. Meaning that the one side has a natural faceted end.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Double-terminated crystals obviously couldn't form like this.&lt;/p&gt;&#xA;" OwnerUserId="115" LastEditorDisplayName="user20559" LastEditDate="2021-05-12T10:38:02.827" LastActivityDate="2021-05-12T10:38:02.827" Title="How and where do double-terminated crystals form?" Tags="|geology|mineralogy|minerals|crystallography|crystals|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="326" PostTypeId="2" ParentId="321" CreationDate="2014-04-18T13:27:08.150" Score="19" Body="&lt;h3&gt;The subtropical jetstream&lt;/h3&gt;&#xA;&lt;p&gt;The subtropical jetstream can be explained with angular momentum arguments.  In an idealized circulation model of the atmosphere, there is a hadley cell that circulates upward at the equator, poleward along the tropical tropopause, downward around 30 N/S and equatorward at the surface.  Parcels rising at the equator have a fair bit of angular momentum from the rotation of the Earth.  As these parcels move poleward they tend to conserve this momentum and this manifests as a westerly wind.&lt;/p&gt;&#xA;&lt;p&gt;The subtropical jet is weak in the summer (ITZC and maxmium solar heating disrupt the hadley cell in that hemisphere), strong in the winter and is generally fixed at around 30 N/S and at a higher altitude than the polar jet.&lt;/p&gt;&#xA;&lt;h3&gt;The polar jetstream&lt;/h3&gt;&#xA;&lt;p&gt;The polar jetstream draws its energy from horizontal temperature gradients in the lower troposphere as a consequence of the thermal wind.  To understand the thermal wind, consider a temperature gradient at the surface, cold toward the pole and warm toward the equator.  Over the cold air, heights of pressure levels will be lower than normal and over the warm air the heights will be higher than normal.  If you look at any pressure level this will result in a height gradient with higher heights toward the equatot.  This gradient will increase with height.  The geostrophic wind is proportional to the height gradient and thus increases with height.  The polar jet exists where these surface temperature gradients are strong but above them around 250 mb.&lt;/p&gt;&#xA;&lt;p&gt;You will find the polar jet wandering around and associated with the strong surface fronts that come out out of the poles and into the mid-latitudes.  It will be stronger in the winter when the fronts are stronger.  During the summer the jet will remain at higher latitudes and in the winter can dip well into the mid-latitudes.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-04-18T14:21:55.147" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="327" PostTypeId="2" ParentId="315" CreationDate="2014-04-18T14:39:34.590" Score="16" Body="&lt;p&gt;Caesium-137 is not used in the fracking process.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Caesium-137&lt;/strong&gt; is used as a source of gamma-rays in some logging tools, most notably &lt;a href=&quot;https://en.wikipedia.org/wiki/Density_logging&quot;&gt;the density tool&lt;/a&gt; (&lt;a href=&quot;http://www.halliburton.com/public/lp/contents/Data_Sheets/web/I_through_Z/L&amp;amp;P14_01.asp&quot;&gt;one example&lt;/a&gt;), and some other instruments such as flowmeters. This is what the story you linked to is about. Logging tools are used after drilling to measure the properties of the rocks in the borehole, and thereby calibrate geological models of the subsurface. These sources are valuable, and should be secured and only handled by trained engineers. The caesium is completely enclosed in the tool, and none is left in the subsurface, unless something goes badly wrong with the logging process and a tool is lost.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Caesium-133&lt;/strong&gt;, the naturally-occurring non-radioactive isotope of caesium, is sometimes used in drilling and fracking fluids in the form of caesium formate brine. Its high density (ca. 2300 kg/m³) improves drilling efficiency and rig safety, and assists with pressure build-up for induced fracturing. It's still pretty valuable stuff, so companies often rent it, retrieving as much as possible (5–15% losses are common, however) and paying only for what they use. &lt;a href=&quot;http://www.formatebrines.com/&quot;&gt;Cabot&lt;/a&gt; is one vendor of such brines. &lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2014-04-19T01:13:51.453" LastActivityDate="2014-04-19T01:13:51.453" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="328" PostTypeId="2" ParentId="316" CreationDate="2014-04-18T15:28:08.647" Score="15" Body="&lt;p&gt;I don't know about the size of land masses, but their distribution and the shape of ocean basins definitely play a big role.&#xA;When considering the ideal case of an all-ocean globe, i.e. one with &lt;em&gt;no&lt;/em&gt; land masses (equilibrium tidal theory), the combined effect of sun and moon give a theoretical tidal range of less than 1 m&lt;sup&gt;(1)&lt;/sup&gt;. As tidal ranges can be much larger than this,  there are other effects that has a greater influence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Bay of Fundy for example, is one of the places with the largest difference between low tide and high tide, at about 16 m. The large difference in this location has to do with the shape of the bay. The bay has a natural frequency for waves that is about the same as the frequency of the tide itself, giving an amplification of the tidal amplitude. In addition there is a funnelling effect in the inner part of the bay, giving an additional contribution.&lt;sup&gt;(2)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another example of large tidal differences is the English channel, particularly the French side. In this case the tides are large at least partly because the tide moves as a coastal trapped Kelvin wave. These are waves that propagate along land, with the land to the right when looking in the direction of propagation (on the Northern hemisphere, land to the right on SH). The amplitude of the wave is highest near the coast, decaying exponentially away from the coast. As the tide in the English channel moves northward, the largest tidal range is on the French side.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regard to guessing the tidal range, this is not entirely straight forward.&#xA;First, when discussing tides, we generally split the tidal potential into a series of oscillations having different frequencies, mainly either diurnal (period of ~24 h) or semi-diurnal (period of ~12 h).&#xA;These given frequencies are obtained through trigonometric considerations, and depend on the latitude of the point, the declination of the moon or sun relative to the equator, and the hour angle.&#xA;(The hour angle is basically the longitudinal difference between the sub-lunar point and the point we consider.)&#xA;Each of these components can vary in time and space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further, the pattern of the amplitudes of each component is not necessarily simple. In addition to the differences in potential, the topography modifies it.&#xA;See for example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/EyKBR.jpg&quot; alt=&quot;https://en.wikipedia.org/wiki/File%3aM2_tidal_constituent.jpg&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;from &lt;a href=&quot;https://en.wikipedia.org/wiki/File%3aM2_tidal_constituent.jpg&quot;&gt;wikipedia&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;which shows the amplitude of the M2 tidal component.&#xA;This is the strongest semi-diurnal tidal component caused by the moon. You'll notice that there are places where the amplitude is zero, i.e. this component causes no tides here.&#xA;These are known as amphidromic points.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, depending on which components dominate at a given location, you can have either a mainly semi-diurnal tide, a mainly diurnal tide, or a mixed tide where there are two high tides in a day, but one has lower amplitude than the other.  A sketch of which can be seen here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/J3EqY.png&quot; alt=&quot;sketch of tide amplitudes&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;from &lt;a href=&quot;http://en.wikipedia.org/wiki/File:Tide_type.svg&quot;&gt;wikipedia&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;(1)&lt;/sup&gt; Pugh, David T. (1987) &lt;em&gt;Tides, surges and mean sea level&lt;/em&gt;, chapter 3.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;(2)&lt;/sup&gt; &lt;a href=&quot;http://www.bayoffundy.com/about/highest-tides/&quot;&gt;http://www.bayoffundy.com/about/highest-tides/&lt;/a&gt; (for lack of better sources)&lt;/p&gt;&#xA;" OwnerUserId="129" LastEditorUserId="129" LastEditDate="2014-04-20T22:29:16.097" LastActivityDate="2014-04-20T22:29:16.097" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="329" PostTypeId="2" ParentId="324" CreationDate="2014-04-18T15:58:18.857" Score="11" Body="&lt;p&gt;Double-terminated crystals can from by crystallizing from a melt. The crystallization nucleus has to float freely in the magma chamber. As long as no other crystals obstruct the growth the crystal will grow in its own characteristic form (euhedral). This happens for example with feldspar crystals. (Example: &lt;a href=&quot;http://www.erdwissen.ch/wp-content/uploads/2010/12/granit-feldspat.jpg&quot;&gt;http://www.erdwissen.ch/wp-content/uploads/2010/12/granit-feldspat.jpg&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the crystal forms in a fluid cavity it can form double-terminations when it doesn't grow with the c-Axis normal to the wall. Sometimes crystals also grow with their c-Axis parallel to the wall (Example: &lt;a href=&quot;http://wannenkopfe.strahlen.org/titanite.html&quot;&gt;http://wannenkopfe.strahlen.org/titanite.html&lt;/a&gt;). Probably super cooled pegmatitic melts also form free floating double-terminated crystals like tourmaline.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the smaller scale (microscope and electron microprobe) double terminated crystals are pretty common in metamorphic rocks. Sections cut parallel to the stretching lineation (or the lineation which elongated crystals aligned themselves to) will show many porphyroblastic crystals with double-terminations. &lt;/p&gt;&#xA;" OwnerUserId="23" LastEditorUserId="44" LastEditDate="2014-04-18T23:40:44.857" LastActivityDate="2014-04-18T23:40:44.857" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="330" PostTypeId="2" ParentId="310" CreationDate="2014-04-18T16:13:50.230" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;In the early stages of crystallization, the ions that form&#xA;  high-temperature minerals are depleted from the melt. Rare ions that&#xA;  do not participate in the crystallization of common rock-forming&#xA;  minerals become concentrated in the melt and in the excluded water.&#xA;  These ions can form the rare minerals that are often found in&#xA;  pegmatites... rare elements concentrated in large crystals make pegmatite a&#xA;  potential source of valuable ore.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://geology.com/rocks/pegmatite.shtml&quot; rel=&quot;nofollow&quot;&gt;What is Pegmatite?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;They are typically found in association with alkaline magmas, as these are highly differentiated as they slowly crystallise. The slow crystallisation of the magmas enriches the leftover melt in the rare earths as they don't tend to form minerals early in the crystallisation process. Think of it perhaps being like freeze distillation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Pegmatites are important because they often contain rare earth minerals...&quot;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Pegmatite&quot; rel=&quot;nofollow&quot;&gt;Pegmatite (Wikipedia)&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="140" LastEditorUserId="6093" LastEditDate="2016-10-05T14:16:52.707" LastActivityDate="2016-10-05T14:16:52.707" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="331" PostTypeId="1" AcceptedAnswerId="9310" CreationDate="2014-04-18T18:19:22.410" Score="15" ViewCount="336" Body="&lt;p&gt;When defining an area average of sea ice thickness, it is important to distinguish between an average taken over an ocean area&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$h_1 = \sum \frac{\text{sea ice thickness (in area)}}{\text{area}_\text{ice} + \text{area}_\text{water}}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and an average taken over the ice covered area&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$h_2 = \sum \frac{\text{sea ice thickness (in area)}}{\text{area}_\text{ice}}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The notations $h_1$ and $h_2$ are mine. I've seen both quantities referred to as “effective ice thickness”. I might go with &lt;a href=&quot;http://dx.doi.org/10.1175/JCLI-D-13-00301.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Holland et al 2014&lt;/a&gt; and call $h_1$ “effective ice thickness” and $h_2$ “average ice thickness”.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an example think of a multi-category sea ice model: Let's say an ocean grid cell has a sea ice concentration of 50 %. Thus 50 % of the ocean grid cell is covered by water. The other 50 % of the grid cell is half-filled with 50 cm thick ice and half filled with 30 cm thick ice. For this case $h_1$ and $h_2$ would be 0.2 m and 0.4 m:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\begin{align}&#xA;h_1 &amp;amp;= 0.5 \times 0 \text{m} + 0.25 \times 0.5 \text{m} + 0.25 \times 0.3 \text{m} = 0.2 \text{m} \\&#xA;h_2 &amp;amp;= 0.5 \times 0.5 \text{m} + 0.5 \times 0.3 \text{m} = 0.4 \text{m} &#xA;\end{align}$$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both variables can be useful. As I have seen conflicting names, I am a bit puzzled with the naming for $h_1$ and $h_2$. &lt;strong&gt;What are the standard names for $h_1$ and $h_2$ used in the sea ice community?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="124" LastEditorUserId="5594" LastEditDate="2016-12-02T12:15:40.477" LastActivityDate="2016-12-16T23:14:33.913" Title="Naming convention for sea ice thickness per unit area of ice or ocean" Tags="|terminology|sea-ice|cryosphere|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="332" PostTypeId="1" AcceptedAnswerId="823" CreationDate="2014-04-18T19:40:06.747" Score="9" ViewCount="2522" Body="&lt;p&gt;What is the official letter for the bedrock soil horizon? I know that the letters to represent the A, B, and C horizons are widespread, but the fourth layer (bedrock) is referred to with different names. Some call it the D-Horizon, some the R-Horizon, and some just say bedrock. Is there any standard or official term, and if so, what is it?&lt;/p&gt;&#xA;" OwnerUserId="153" LastEditorUserId="87" LastEditDate="2014-05-08T14:46:44.050" LastActivityDate="2014-11-21T15:29:11.473" Title="Horizon letter for bedrock" Tags="|terminology|soil|bedrock|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="333" PostTypeId="2" ParentId="115" CreationDate="2014-04-18T20:24:54.620" Score="13" Body="&lt;p&gt;Certainly there are such places. They are simply spots where the nearby rocks have a high concentration of magnetic minerals with a strong remanent magnetization. They're not necessarily literal hills: any kind of topography can be magnetized in this way. I'm not sure what exactly you mean by &quot;drives your compass crazy&quot; -- its direction will be affected, but it won't spin around madly since there's still a field for it to align to.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These phenomena are called &lt;a href=&quot;http://en.wikipedia.org/wiki/Magnetic_anomaly&quot;&gt;magnetic anomalies&lt;/a&gt;, and their effect on a compass is called &lt;a href=&quot;http://en.wikipedia.org/wiki/Magnetic_deviation&quot;&gt;magnetic deviation&lt;/a&gt;. You can get an idea of anomalies at a large scale by looking at the &lt;a href=&quot;http://geomag.org/models/wdmam.html&quot;&gt;World Digital Magnetic Anomaly Map&lt;/a&gt; -- however, this map shows anomalies as measured or inferred at 5km above sea level, so small-scale surface features won't show up well. You'll see that, in Europe, there are a lot of anomalies in north-eastern regions (corresponding to iron ore deposits, I suspect) and in Iceland (corresponding to lava flows). At the surface level, there is a fairly recent &lt;a href=&quot;http://www.annalsofgeophysics.eu/index.php/annals/article/viewFile/5575/6184&quot;&gt;magnetic declination chart of Europe&lt;/a&gt;, but the spatial resolution is too low for the small, intense features which you seem to be interested in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think these small-scale magnetic anomalies are mainly of interest to navigators (marine ones might be marked on nautical charts -- I'm not sure) and possibly to exploration geophysicists (who might use them to infer the presence of ore bodies). Unfortunately, data collected for mineral exploration purposes tends to be kept private for commercial reasons. However, geological maps can give you some clues: volcanic rocks tend to be relatively magnetic so if they're near the surface they're good candidates. I found &lt;a href=&quot;http://www.ipgp.fr/~legoff/Download-PDF/ArcheoItalia/Tanguy-LeGoff-PEPI2004.pdf&quot;&gt;this paper about magnetic anomalies on Mount Etna&lt;/a&gt; which shows magnetic declination varying by about five degrees across different sites on the volcano.&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2014-04-19T09:04:49.703" LastActivityDate="2014-04-19T09:04:49.703" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="334" PostTypeId="1" AcceptedAnswerId="2590" CreationDate="2014-04-18T21:34:37.103" Score="21" ViewCount="1993" Body="&lt;p&gt;The classic Troodos Ophiolite in Cyprus has been uplifted by a 'serpentinization event'. Upper mantle (peridotite) has been serpentinized creating a buoyant diapir. This has uplifted the ocean crust sufficiently for it to be thrust over continental crust (underlying continental crust has been inferred from gravitational surveys).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The last sentence of the abstract of &lt;a href=&quot;http://gsabulletin.gsapubs.org/content/88/12/1763&quot;&gt;&quot;Tertiary uplift history of the Troodos massif, Cyprus&quot;, AHF Robertson&lt;/a&gt; says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The dominant driving force may have involved the liberation of water&#xA;  from a subduction zone dipping northward beneath Cyprus.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This makes sense - serpentinization is the alteration process of olivine -&gt; serpentine in the presence of water. And, as we know, subduction slabs release fluids (primarily water) into the overlying mantle wedge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These fluids usually promote partial melting leading to andesite arc volcanism. However, Cyprus has this big serpentinite diapir instead of volcanism. Why?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What causes the fluids from the subducting slab to occasionally result in serpentinization of the mantle wedge instead of partial melting?&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorDisplayName="user12525" LastEditDate="2019-04-23T08:43:29.107" LastActivityDate="2023-01-04T00:27:25.880" Title="Why does a subduction zone produce a serpentinization diapir rather than volcanism?" Tags="|geology|plate-tectonics|petrology|subduction|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="335" PostTypeId="1" AcceptedAnswerId="339" CreationDate="2014-04-18T21:55:18.133" Score="7" ViewCount="3492" Body="&lt;p&gt;Recently I checked a picture about the geologic layers of the Earth, and I saw that the mantle is divided into upper and lower mantle. What's the reason of this differentiation?&lt;/p&gt;&#xA;" OwnerUserId="68" LastActivityDate="2015-11-03T21:04:49.033" Title="What's the difference between the upper &amp; lower mantle?" Tags="|mantle|geologic-layers|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="336" PostTypeId="1" AcceptedAnswerId="338" CreationDate="2014-04-18T21:59:23.937" Score="8" ViewCount="121" Body="&lt;p&gt;I've heard long ago that the rock material deeply below surface are checked by a device that acts like radar - it sends radiowaves into the ground, and geologists find out from reflections that what type of rock can be found there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What's the name of this device or method, and how is it possible to differentiate rocks from radiowave reflection?&lt;/p&gt;&#xA;" OwnerUserId="68" LastEditorUserId="44" LastEditDate="2014-04-18T22:14:27.277" LastActivityDate="2014-04-18T23:32:57.397" Title="Checking the bedrock with radiowaves - how does it work?" Tags="|geophysics|measurements|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="337" PostTypeId="2" ParentId="322" CreationDate="2014-04-18T22:09:49.647" Score="12" Body="&lt;p&gt;The reason minerals like quarts and diamonds vary in color is generally caused by the chemical elements involved while the crystal is being formed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Chemicals&lt;/strong&gt;&lt;br&gt;&#xA;Different colors can be created by different chemicals. Amethyst for example has traces of iron built into its crystalline structure giving it a purple hue. Iron can also give crystals a yellow hue.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;[edit: See Gimelist's answer for a much more detailed and colorful explanation]&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Growth Imperfections&lt;/strong&gt;&lt;br&gt;&#xA;Some colors, like in smoky quartz, are from growth imperfections. These imperfections change the way the crystal reflects light, which changes the appearance of coloration.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Light&lt;/strong&gt;&lt;br&gt;&#xA;Part of the color seen when looking at a crystal is light. When light enters a crystal its spectrum is broken apart, and part of it is absorbed while other parts are reflected. This changes the &lt;em&gt;apparent&lt;/em&gt; color of the crystal.&lt;/p&gt;&#xA;" OwnerUserId="115" LastEditorUserId="115" LastEditDate="2019-01-22T04:05:35.457" LastActivityDate="2019-01-22T04:05:35.457" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="338" PostTypeId="2" ParentId="336" CreationDate="2014-04-18T22:14:05.513" Score="6" Body="&lt;p&gt;Do you mean &lt;a href=&quot;http://en.wikipedia.org/wiki/Ground-penetrating_radar&quot; rel=&quot;noreferrer&quot;&gt;Ground Penetrating Radar&lt;/a&gt;? This is typically limited to very shallow depths though - eg. archaeological investigations, police forensics (finding graves), and civil engineering site investigations. The latter can go to tens of meters and would be used for planning foundations, excavations, etc (I know of an example where it was used for site characterization for a planned rowing lake). The depth limit is typically due to attenuation in brackish groundwaters. Ice applications can typically go further due to the lack of conducting liquid water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or are you thinking of &lt;a href=&quot;http://principles.ou.edu/seismic_explo/reflect/reflect.html&quot; rel=&quot;noreferrer&quot;&gt;Reflection ('Active') Seismic Surveys&lt;/a&gt;, which work on a similar principle but using sound waves. Sound waves can travel to the far side of the Earth (cf. large earthquake 'P' waves), but reflection surveys are typically looking at the upper crust (few km) and rarely go beyond the base of the crust (aka the 'Moho') which is a strong seismic reflector. Reflection seismic surveys are widely used in the oil business.&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorUserId="44" LastEditDate="2014-04-18T23:32:57.397" LastActivityDate="2014-04-18T23:32:57.397" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="339" PostTypeId="2" ParentId="335" CreationDate="2014-04-18T22:37:30.857" Score="9" Body="&lt;p&gt;The boundary between the upper and lower mantle is today believed to be due to the phase change because of increasing pressure of:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\text{Ringwoodite} \xrightarrow{\text{660 km, about 24.5 GPa}} \text{Mg-Perovskite} + \text{Mg-Wüstite}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The boundary was originally found in the form of a seismic discontinuity (the &quot;660 km discontinuity&quot;). This information was combined with the knowledge that the most primitive meteorites have roughly the chemistry of the bulk Earth. Accounting for the chemical differentiation (into crust, mantle and core) the chemistry of the mantle was known. Additional clues for the chemistry come from mantle-xenoliths. The crystal structure (important for the density of a chemical compound or mineral) can be deduced from high pressure experiments and natural laboratories such as meteorite impact craters. For example, the mineral majorite was found, which is also postulated for the lower mantle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some literature on this: &lt;a href=&quot;http://mahi.ucsd.edu/shearer/PDF/30NT92a.pdf&quot; rel=&quot;nofollow&quot;&gt;http://mahi.ucsd.edu/shearer/PDF/30NT92a.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="23" LastEditorUserId="67" LastEditDate="2014-05-17T03:29:38.580" LastActivityDate="2014-05-17T03:29:38.580" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="340" PostTypeId="1" AcceptedAnswerId="357" CreationDate="2014-04-19T00:00:06.673" Score="16" ViewCount="3794" Body="&lt;p&gt;I read this explanation about rivers: &#xA;&quot;As the river erodes laterally, to the right side then the left side, it forms large bends, and then horseshoe-like loops called meanders&quot; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why does the river erode laterally to the right side then the left side? Surely it would erode both sides at the same time and therefore the river would go in a straight line. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could someone please explain more clearly how these meanders in rivers form?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="10681" LastEditDate="2018-09-25T18:43:01.563" LastActivityDate="2018-09-25T18:43:01.563" Title="How does a meandering river form?" Tags="|hydrology|rivers|potamology|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="341" PostTypeId="2" ParentId="320" CreationDate="2014-04-19T00:00:45.507" Score="10" Body="&lt;p&gt;The usual panacea for numeric stability problems is to decrease the timestep. It doesn't always help (and, indeed, in some cases can even make the instability worse), but it's generally the first thing to try.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, a shorter timestep costs more computer time.  Another approach to try, if reducing the timestep doesn't help, or leads to unacceptably poor performance, is to either refine or, somewhat paradoxically, coarsen the mesh in the problematic regions.  (Which one of these is more likely to help depends on the exact cause of the instability.)  If this alone doesn't help either, try adjusting the mesh &lt;em&gt;and&lt;/em&gt; decreasing the timestep.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ultimately, the &lt;em&gt;best&lt;/em&gt; way to fix such problems is usually to switch to a more stable timestepping method.  As a general rule of thumb, higher-order methods are more stable than lower-order methods (up to some point, anyway), and implicit methods are more stable than explicit.  In both cases, stability comes at the cost of extra computational effort, but it's still generally cheaper than just decreasing the timestep enough to achieve comparable stability.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, I'm not personally familiar with the MIKE3 software, and have no idea what timestepping algorithm(s) it uses, or whether there's any way for the end user to adjust the algorithm.&lt;/p&gt;&#xA;" OwnerUserId="142" LastActivityDate="2014-04-19T00:00:45.507" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="342" PostTypeId="1" CreationDate="2014-04-19T00:14:11.717" Score="26" ViewCount="950" Body="&lt;p&gt;It has been observed that the shape of a meandering river is roughly circular, not sinusoidal (Leopold and Wolman 1960).  It has also been observed that the following mathematical relationships tends to hold:.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\lambda \sim 11 w$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$r \sim 2.3w$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where $r$ is the radius of the circular bend, $w$ is the width of the river, and $\lambda$ is the length of the meander (wavelength), as labelled in the diagram below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/9JZDG.png&quot; alt=&quot;River equations diagram&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since this pattern was first observed in 1960, has a theoretical model of meandering rivers been obtained that explains the above observed relationships and if so, what is the theoretical explanation of this relationship?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note:  Given $r \sim 2.3 w$, it can be shown that $\lambda \sim 11 w$ from geometrical principles, or vice versa.  For example $\lambda$ should be equal to&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$0.5w + 2r + w + 2r + 0.5w = 2w + 4r = 2w + 4(2.3w) = 11.2 w$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So since the two equations are not completely independent, the question is how could either of these relations be determined from a theoretical basis.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;References&lt;/h3&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Leopold, Luna B. and M. Gordon Wolman, 1960, &lt;em&gt;River Meanders&lt;/em&gt;, Geological Society of America Bulletin, no. 6;769-793, &lt;a href=&quot;https://www.usu.edu/jackschmidt/files/uploads/Fluvial_2013_Labs/Leopold_Wolman_1960.pdf&quot; rel=&quot;noreferrer&quot;&gt;https://www.usu.edu/jackschmidt/files/uploads/Fluvial_2013_Labs/Leopold_Wolman_1960.pdf&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="51" LastEditorUserId="56" LastEditDate="2014-07-02T10:40:28.047" LastActivityDate="2014-09-19T01:38:17.567" Title="How can the following equations for meandering rivers be theoretically obtained?" Tags="|rivers|potamology|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="343" PostTypeId="2" ParentId="320" CreationDate="2014-04-19T00:18:55.133" Score="12" Body="&lt;p&gt;Almost all finite methods that use forward time models adhere to the Courant-Friedrichs-Lewy law which calculates a courant number and compares it to a $C_{max}$, which is what determines stability, so for 2-D:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$C = \frac {V_xdt}{dx}  + \frac{V_ydt}{dy} \ge C_{max}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where $C$ is the courant number, $V_i$ is the velocity in subscripted direction, $dx$ or $dy$ is the length interval in specified direction and $dt$ is the specified time step. If you are getting numerical instability, increasing the mesh spacing will lower the courant number, but then you might be missing the dynamics you want to capture. If you decrease the time step, it will take longer for the dynamics to develop computationally. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One way to solve this computational problem is to code in a dynamic time step: Keep calculating the $C$ and $C_{max}$. If $C &amp;gt; C_{max}$, then have the model lower the step by half. Check again, then reset for the next step so you can have larger timesteps for &quot;less dynamic&quot; times. I have implemented this many times in other models and it has worked well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another possibility might be that you have high aspect ratios in your mesh: if your $x$ direction is 10 km and your $y$ is 1 km, a $10:1$ aspect ratio is very high. In your case, since the model package you use are triangles, you want the angles in the triangle grid to be as acute as possible. Obtuse angles would mean high aspect ration, in general. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Like llmari, I am not familiar with hydrodynamic models, so I do not do specifics. My expertise are in both mantle convection and plate flexure models. I hope this helps.&lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="32" LastEditDate="2014-04-24T15:00:07.403" LastActivityDate="2014-04-24T15:00:07.403" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="344" PostTypeId="1" AcceptedAnswerId="405" CreationDate="2014-04-19T01:08:08.013" Score="11" ViewCount="1368" Body="&lt;p&gt;It is well known that the jet stream follows an overall meandering pattern, but what is less well known is that this meandering pattern itself moves as a wave with a velocity much slower than the velocity of the jet stream itself.  So why does this meandering wave propagate, and what causes the meandering pattern in the first place?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="64" LastEditDate="2014-04-28T23:44:03.047" LastActivityDate="2014-04-28T23:44:03.047" Title="Why does the meandering pattern of the jet stream itself propagate?" Tags="|atmosphere|meteorology|atmospheric-circulation|jet-stream|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="345" PostTypeId="1" AcceptedAnswerId="3126" CreationDate="2014-04-19T02:05:32.010" Score="17" ViewCount="20664" Body="&lt;p&gt;It is well known that the purple hue that is characteristic of the amethyst quartz ($\ce{SiO2}$) will fade if the crystal is exposed to light for a prolonged period of time.  What is the underlying mechanism of this change?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorDisplayName="user12525" LastEditDate="2019-04-27T09:35:17.933" LastActivityDate="2019-04-27T09:35:17.933" Title="Why does the colour of amethyst fade if exposed to too much light?" Tags="|mineralogy|minerals|crystals|crystallography|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="346" PostTypeId="1" CreationDate="2014-04-19T03:25:22.627" Score="28" ViewCount="642" Body="&lt;p&gt;Since &lt;a href=&quot;http://dx.doi.org/10.1007%2FBF01821169&quot;&gt;Harland&lt;/a&gt;'s sedimentary work and &lt;a href=&quot;https://en.wikipedia.org/wiki/Mikhail_Budyko&quot;&gt;Budyko&lt;/a&gt;'s models in the 1960s, geologists have hypothesized that the Earth may once have been completely frozen. There are &lt;a href=&quot;https://en.wikipedia.org/wiki/Snowball_Earth#Evidence&quot;&gt;various lines of evidence&lt;/a&gt; for this event.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would it take to conclusively confirm or refute this hypothesis, short of going back in a time machine?&lt;/p&gt;&#xA;" OwnerUserId="154" LastEditorUserId="94" LastEditDate="2014-07-04T08:09:48.730" LastActivityDate="2018-05-08T08:30:08.737" Title="What would it take to confirm or refute the Snowball Earth Hypothesis?" Tags="|paleoclimatology|glaciation|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="347" PostTypeId="2" ParentId="340" CreationDate="2014-04-19T03:43:50.043" Score="14" Body="&lt;p&gt;Meanders amplify themselves--the stream tends to erode on the outside of the meander (forming a cut bank) and deposit sediment on the inside (forming a point bar).  Eventually, the meander will propagate so far from the stream's mean path that the stream cuts across it.  Eventually, the old meander will turn into an oxbow lake and fill in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to why it erodes on the outside and deposits on the inside, the simple answer is that the water has to travel farther on the outside, so it flows faster and erodes more, while the water on the inside moves slower and deposits its sediment.  A more complete answer involves vortices crossing the river bed carrying sediment from the outside to the inside.&lt;/p&gt;&#xA;" OwnerUserId="40" LastActivityDate="2014-04-19T03:43:50.043" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="348" PostTypeId="2" ParentId="218" CreationDate="2014-04-19T03:53:08.790" Score="8" Body="&lt;p&gt;The microseism is ocean waves that couple to the ground to make Rayleigh waves.  The ocean waves are gravity waves which are dispersive (different frequencies travel at different speeds), and 0.2 Hz (not 20 mHz) is the frequency of the waves that travel at the same speed as storm winds to which they couple.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ground motion doesn't die off, even thousands of kilometers inland, because Rayleigh waves are bound to the surface (so waves from a point source would spread circularly instead of spherically).  The waves are produced all along the coast, which negates the circular spreading.&lt;/p&gt;&#xA;" OwnerUserId="40" LastActivityDate="2014-04-19T03:53:08.790" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="349" PostTypeId="1" CreationDate="2014-04-19T03:57:20.750" Score="16" ViewCount="1078" Body="&lt;p&gt;Note that it needs to include coal and chert, therefore the common answer &quot;a rock is made of minerals&quot; is incomplete.  &lt;/p&gt;&#xA;" OwnerUserId="40" LastEditorDisplayName="user20559" LastEditDate="2021-05-12T10:38:11.697" LastActivityDate="2021-05-17T03:49:21.187" Title="What is a good definition of the word &quot;rock&quot; for teaching?" Tags="|geology|rocks|petrology|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="350" PostTypeId="1" CreationDate="2014-04-19T04:24:42.780" Score="14" ViewCount="397" Body="&lt;p&gt;This is something I've never quite understood from a geology class I took years ago:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider the following picture (courtesy of wikipedia)&#xA; &lt;img src=&quot;https://i.stack.imgur.com/OGFh7.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously, we can't possibly have sensors deep in the mantle (or core).  So, how exactly are these wave speeds determined? &lt;/p&gt;&#xA;" OwnerUserId="154" LastEditorUserId="154" LastEditDate="2014-04-19T05:12:52.197" LastActivityDate="2014-04-19T11:39:01.097" Title="How are subsurface wave speeds determined without subsurface sensors?" Tags="|geophysics|measurements|seismology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="351" PostTypeId="2" ParentId="350" CreationDate="2014-04-19T04:59:09.093" Score="14" Body="&lt;p&gt;This is a good question, and the basic answer is earthquake seismology. To answer this question, lets accept a fact: Waves propagate through the least time pathway, and not the least distance path. This property of physics is known as &lt;a href=&quot;http://en.wikipedia.org/wiki/Fermat%27s_principle&quot; rel=&quot;noreferrer&quot;&gt;Fermat's principle&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When an Earthquake occurs, energy propagates similar to a ripple of water, and spreads. Each point on this ripple can be modeled as a ray, each following its least time path through the Earth. As these rays propagate, they reflect and refract  off heterogeneities inside the earth. These reflections are important: we can detect these reflections using surface seismometers. Using multiple seismometers, and the location of the source (earthquake), we can calculate the &quot;lag&quot; between when the closest seismometer detects the earthquake and the others(further from the source). This lag time can be used as a proxy for the depth of the reflected wave's heterogeneity. Using how deep this reflection originates, we can then figure out the least time path of the wave in terms of actual distance. Velocity is just distance over time, even for seismic waves. So since we have the distance traveled by the wave, and the time the wave took to get to the receiver, we can complete the equation (distance/time). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In actual practice, this process is far more complex, as you have to look for many different waveforms:  &lt;img src=&quot;https://i.stack.imgur.com/iiGl2.png&quot; alt=&quot;enter image description here&quot;&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The picture above illustrates an earthquake sending waveforms through the earth. The SKS wave is a shear wave that refracts into the liquid outer core, turns into a compressional wave (since shear waves cannot propagate through liquid), and then is converted again to a shear wave as it enters the mantle and goes to the surface. A trained seismologist looks at the readings from seismometers to tease out specific waves, which we know the properties of, to determine properties of the planet's interior. The speeds of these waves are highly dependent on the assumed densities and other rock properties of the crust, mantle, and core.&lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="32" LastEditDate="2014-04-19T05:08:08.143" LastActivityDate="2014-04-19T05:08:08.143" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="352" PostTypeId="1" AcceptedAnswerId="359" CreationDate="2014-04-19T05:35:02.087" Score="23" ViewCount="11816" Body="&lt;p&gt;What features should I look for to determine each of these kinds of waves in a &lt;a href=&quot;http://en.wikipedia.org/wiki/Seismogram&quot;&gt;seismogram&lt;/a&gt;?  What signal processing methods (filters, transforms, etc...) should I use to determine them?&lt;/p&gt;&#xA;" OwnerUserId="154" LastEditorUserId="53" LastEditDate="2014-04-19T16:40:42.477" LastActivityDate="2014-04-25T22:58:17.203" Title="How to distinguish P, S, Love, and Rayleigh waves in a seismogram?" Tags="|geophysics|seismology|waves|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="353" PostTypeId="1" CreationDate="2014-04-19T06:03:15.510" Score="14" ViewCount="723" Body="&lt;p&gt;I remember reading in a geology book that a seismogram is a convolution between a source signal and propagation effects.  In layman's terms, what does this really mean?&lt;/p&gt;&#xA;" OwnerUserId="154" LastEditorUserId="154" LastEditDate="2014-04-19T06:25:53.517" LastActivityDate="2015-07-16T19:57:14.733" Title="Why is a seismogram interpreted as a convolution?" Tags="|geophysics|seismology|waves|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="354" PostTypeId="1" CreationDate="2014-04-19T06:24:13.340" Score="11" ViewCount="181" Body="&lt;p&gt;Let's assume that a seismogram $s(t)$ is the convolution $s(t)=r(t)g(t)$ between a source signal $r(t)$ and propagation effects $g(t)$. If the source signal $r(t)$ is known, then we can obtain the propagation effects using a Fourier transform; that is,  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Original equation (time domain):  $s(t)=r(t)g(t)$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fourier transform (frequency domain):  $S(w) = R(w)G(w)$&lt;br&gt;&#xA;where $S(w)=\mathcal{F}[s(t)]$, $R(w)=\mathcal{F}[r(t)]$ and $G(w)=\mathcal{F}[g(t)]$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Solve for the unknown:  $G(w) = \dfrac{S(w)}{R(w)}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Inverse Fourier transform:  $g(t) = \mathcal{F}^{-1}\left[\dfrac{S(w)}{R(w)}\right]$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;My question&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How do we use the information in $g(t)$ to determine the composition of the medium that the wave is traveling through? Moreover, knowing that the earth is heterogeneous, how can we isolate any one single substance or rock type?  How accurate is this kind of measurement?  How can we minimize the uncertainty in this measurement?&lt;/p&gt;&#xA;" OwnerUserId="154" LastEditorUserId="67" LastEditDate="2014-05-13T23:32:01.090" LastActivityDate="2014-05-13T23:32:01.090" Title="How do we determine subsurface composition?" Tags="|geophysics|measurements|seismology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="355" PostTypeId="2" ParentId="319" CreationDate="2014-04-19T07:50:55.630" Score="6" Body="&lt;p&gt;At μ/g level some decade ago, they were explained as forming in relation to the oxygenation of the atmosphere, as photosynthetic life developed changing a reducing environment to an oxygenated one, iron oxides formed precipitating out of seawater in variable bands related to local (or possibly seasonal) oxygen availability.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Though this traditional explanation is being challenged, with research claiming the iron and silica compounds came from hydrothermal vents on the ocean floor known as black smokers. This theory has nothing to do with the oxygenation of the atmosphere, with the suggestion that BIFs may still be forming at present.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further reading:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Banded_iron_formation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Banded Iron Formation&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Oxygenation_Event&quot; rel=&quot;nofollow noreferrer&quot;&gt;Great Oxygenation Event&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://phys.org/news/2015-03-banded-ironstone-formation-theory-current.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Banded ironstone formation theory challenges current thinking&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="140" LastEditorUserId="725" LastEditDate="2016-11-26T12:05:45.450" LastActivityDate="2016-11-26T12:05:45.450" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="356" PostTypeId="2" ParentId="353" CreationDate="2014-04-19T09:00:23.040" Score="17" Body="&lt;p&gt;In simplest terms, it simply means that:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;if the source signal is shifted by some amount of time &lt;em&gt;&amp;Delta;t&lt;/em&gt;, but otherwise unchanged, then the seismogram will also be shifted by &lt;em&gt;&amp;Delta;t&lt;/em&gt;, but otherwise unchanged; and&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;the seismogram generated by the sum of two (or more) source signals is the sum of the seismograms that would've been generated by each of the individual source signals.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Basically, it works &lt;em&gt;exactly&lt;/em&gt; like an ordinary echo: what you hear is the original sound, or rather several overlapping echoes of it, each reaching you by a different path, delayed and attenuated by varying amounts during its propagation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mathematically, this process can be represented by &lt;a href=&quot;//en.wikipedia.org/wiki/Convolution&quot;&gt;convolving&lt;/a&gt; the source signal waveform with a function, called the &lt;em&gt;convolution kernel&lt;/em&gt;, that describes how the signal is spread out and split into multiple echoes.  Specifically, the convolution kernel is northing more or less than the waveform of the echo that would, in principle, be produced by an &quot;&lt;a href=&quot;//en.wikipedia.org/wiki/Delta_function&quot;&gt;ideal unit impulse&lt;/a&gt;&quot; source signal &amp;mdash; that is to say, a source signal consisting of a single, infinitesimally short pulse of sound pressure carrying one unit of energy.  For this reason, the convolution kernel is also known as the &lt;a href=&quot;//en.wikipedia.org/wiki/Impulse_response&quot;&gt;impulse response&lt;/a&gt; of the system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The convolution process itself, in the simplest case, merely amounts to summing together several shifted and scaled copies of the impulse response.  Specifically, this is the case when the input signal can be represented (or at least approximated) as a sum of several pure impulses.  More generally, &lt;em&gt;any&lt;/em&gt; input signal can be mathematically represented as a sum &amp;mdash; or, more properly, an &lt;a href=&quot;//en.wikipedia.org/wiki/Integral&quot;&gt;integral&lt;/a&gt; &amp;mdash; of infinitely many tiny impulses spaced infinitely closely*, in which case the resulting seismogram is simply the integral of infinitely many infinitely small shifted copies of the impulse response.  This is precisely what a convolution does.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;*) Mathematicians, and perhaps some physicists, reading this will cringe at this point; while a sum of impulses can indeed approximate any function &lt;a href=&quot;//en.wikipedia.org/wiki/Convergence_of_measures#Weak_convergence_of_measures&quot;&gt;as a measure in the weak sense&lt;/a&gt;, it's not a good approximation is most other senses.  Nonetheless, it &lt;em&gt;is&lt;/em&gt; a rather useful and concrete way to think about convolutions.&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One reason why thinking about seismograms as convolutions is useful is that, if we know the physics of seismic propagation and the geological structure of the area through which the signal propagates, we can calculate the theoretical impulse response function of the system and convolve it with a simulated source signal to obtain a &lt;a href=&quot;//en.wikipedia.org/wiki/Synthetic_seismogram&quot;&gt;synthetic seismogram&lt;/a&gt;.  Conversely, given a real seismogram and the source signal that produced it, we can &lt;a href=&quot;//en.wikipedia.org/wiki/Deconvolution&quot;&gt;deconvolve&lt;/a&gt; them to obtain an approximation of the impulse response, which can then yield &lt;a href=&quot;//en.wikipedia.org/wiki/Seismic_tomography&quot;&gt;tomographical&lt;/a&gt; information about the geology.&lt;/p&gt;&#xA;" OwnerUserId="142" LastActivityDate="2014-04-19T09:00:23.040" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="357" PostTypeId="2" ParentId="340" CreationDate="2014-04-19T10:33:06.483" Score="15" Body="&lt;p&gt;I'm under the impression you're not asking why a meandering river will keep meandering, but why even a straight river will start to meander in the first place. The first is indeed by erosion of the outside of the bends, and deposition on the inside of the bend, which is fairly easy to understand.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the origin of meanders, this is a more complicated matter. Theoretically it might be possible to create a perfectly straight and homogeneous canal, with perfectly laminar flow, and in that case you'd expect equal erosion on both sides of the river. However, nature isn't as straightforward (if you pardon the pun), and rivers never start of perfectly straight, neither is the material ever perfectly homogeneous, and natural laminar waters are very rare.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, even if you would start with a straight canal, some parts of the walls are preferentially eroded over others, causing the canal to no longer be straight. This imperfection will then cause turbulence near the edges of the imperfection, leading to further erosion, thereby creating the seed of a meander.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, even if the walls were perfectly homogeneous, the slightest disturbance in the flow will cause the flow to oscillate leading to inhomogeneous forces on the walls and thus uneven erosion.&lt;/p&gt;&#xA;" OwnerUserId="79" LastEditorUserId="725" LastEditDate="2014-11-29T11:46:23.910" LastActivityDate="2014-11-29T11:46:23.910" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="358" PostTypeId="2" ParentId="167" CreationDate="2014-04-19T11:03:21.540" Score="6" Body="&lt;p&gt;Stromatolites have indeed been used in palaeoclimatic investigations. Here are a couple of papers I found through Google Scholar:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Paul I. Abell, Stanley M. Awramik, Robert H. Osborne, Sterling Tomellini, Plio-pleistocene lacustrine stromatolites from lake Turkana, Kenya: Morphology, stratigraphy and stable isotopes, Sedimentary Geology, Volume 32, Issues 1–2, May 1982, Pages 1-26, ISSN 0037-0738, &lt;a href=&quot;http://dx.doi.org/10.1016/0037-0738%2882%2990011-2&quot;&gt;http://dx.doi.org/10.1016/0037-0738(82)90011-2&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Andrews, J. E. and Brasier, A. T. (2005), Seasonal records of climatic change in annually laminated tufas: short review and future prospects. J. Quaternary Sci., 20: 411–421. doi: 10.1002/jqs.942 &lt;a href=&quot;http://dx.doi.org/10.1002/jqs.942&quot;&gt;http://dx.doi.org/10.1002/jqs.942&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you'll notice, though, these are both relatively young records. I don't know if similar studies have been attempted for Precambrian stromatolites.&lt;/p&gt;&#xA;" OwnerUserId="94" LastActivityDate="2014-04-19T11:03:21.540" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="359" PostTypeId="2" ParentId="352" CreationDate="2014-04-19T11:17:06.983" Score="20" Body="&lt;p&gt;There are two important ways to recognize different types of waves in seismic records:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;strong&gt;Their velocity.&lt;/strong&gt; These waves travel at different speeds: &lt;a href=&quot;http://en.wikipedia.org/wiki/P-wave&quot;&gt;P-waves&lt;/a&gt; are fastest, then &lt;a href=&quot;http://en.wikipedia.org/wiki/S-wave&quot;&gt;S-waves&lt;/a&gt;, then &lt;a href=&quot;http://en.wikipedia.org/wiki/Love_wave&quot;&gt;Love waves&lt;/a&gt;, then &lt;a href=&quot;http://en.wikipedia.org/wiki/Rayleigh_waves&quot;&gt;Rayleigh&lt;/a&gt;. Since seismic recordings are measures of earth displacement, particle velocity, or water pressure over elapsed time, this means the waves show up at different times in the record. If we know or guess their velocities, then we can model the arrival times at various stations and try to recognize the different wavefronts. &lt;a href=&quot;http://geophysics.geoscienceworld.org/content/76/6/V115/F3.large.jpg&quot;&gt;Here's one example&lt;/a&gt; of a shot record (distance &lt;em&gt;x&lt;/em&gt; on the horizontal axis, time &lt;em&gt;t&lt;/em&gt; on the vertical) where you can see reflected P-waves and Rayleigh waves: the slope of the arrivals is a function of wave speed. Once we can discriminate them in some domain (commonly &lt;em&gt;t&lt;/em&gt;–&lt;em&gt;x&lt;/em&gt;, &lt;em&gt;f&lt;/em&gt;–&lt;em&gt;x&lt;/em&gt;, or &lt;em&gt;tau&lt;/em&gt;–&lt;em&gt;p&lt;/em&gt;), we can design filters that exploit this fact.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Their mode of oscillation.&lt;/strong&gt; The waves are distinguished by different types of particple motion. For example, P-waves are longitudinal, S-waves are transverse, Rayleigh waves are circular. So if we have a sensor that can detect particle motion in three dimensions, we can recognize waveforms that way. In the oil &amp;amp; gas industry, where seismic reflection data is an important tool, so-called multi-component (or three-component, or 3C) sensors are now widespread; &lt;a href=&quot;http://www.inovageo.com/products/vectorseis.html&quot;&gt;here's one example&lt;/a&gt;. I'm afraid it's beyond me, but I know one of the methods they use to unpack the different waveform polarizations is singular value decomposition. &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Reconciling P- and S-wave reflections is one of the great problems in reflection seismology today. Everything is made more complicated by the fact that these waves can convert from one to the other. For example, when P-waves reflect from an elastic interface, like rock broundaries, some energy is converted into S-waves. Furthermore, some recording equipment is more sensitive to vertical ground motion than to horizontal (e.g. single component geophones), so our records are often strongly filtered. The result is that unpeeling multiple wave types is not easy.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2014-04-19T11:17:06.983" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="360" PostTypeId="2" ParentId="350" CreationDate="2014-04-19T11:39:01.097" Score="11" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Seismic_tomography&quot;&gt;Tomography!&lt;/a&gt; In essence, we guess some velocities, compute the arrival times our guess implies, compare them with actual arrival times, tweak our answer, and repeat. Seismic tomography is an &lt;a href=&quot;http://en.wikipedia.org/wiki/Well-posed_problem&quot;&gt;ill-posed&lt;/a&gt;, &lt;a href=&quot;http://en.wikipedia.org/wiki/Condition_number&quot;&gt;ill-conditioned&lt;/a&gt; &lt;a href=&quot;http://en.wikipedia.org/wiki/Inverse_problem&quot;&gt;inverse problem&lt;/a&gt;, and one upshot of this is that the solutions are non-unique — there are infinitely many answers! We have to choose one (or, better, many), that are compatible with what we think we know about the earth. Compare this with a medical &lt;a href=&quot;http://en.wikipedia.org/wiki/X-ray_computed_tomography&quot;&gt;computed tomography (CT) scan&lt;/a&gt;, in which there are far fewer unknowns. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the shallow subsurface, down to about 5–10 km in most basins, we have the added advantage of measured &lt;a href=&quot;http://en.wikipedia.org/wiki/Well_logging&quot;&gt;well logs&lt;/a&gt;, specifically sonic logs, which measure the slowness (1/velocity) of ultrasound. As in all inverse problems, extra information constrains the solution greatly.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2014-04-19T11:39:01.097" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="361" PostTypeId="1" AcceptedAnswerId="362" CreationDate="2014-04-19T11:48:11.437" Score="11" ViewCount="585" Body="&lt;p&gt;It is well known that the Earth is not a sphere, but rather it bulges at the equator. Also it is well known that the Earth's crust is composed of 7 or 8 (depending on definition) major tectonic plates, which are able to move on top of the asthenosphere, the upper layer of the Earth's mantle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Due to the equatorial bulge, it would seem as though plates near the equator should not be able to drift away from the equator, and plates away from the equator should not be able to drift near the equator, since they will not be of the right shape to fit over these portions of the Earth. So how are the plates able to drift to and from the equator when the surface of the Earth is shaped differently there?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="28050" LastEditDate="2015-11-10T18:42:04.530" LastActivityDate="2015-11-10T19:07:49.163" Title="Equatorial bulge and tectonic plates" Tags="|geophysics|plate-tectonics|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="362" PostTypeId="2" ParentId="361" CreationDate="2014-04-19T12:05:41.810" Score="18" Body="&lt;p&gt;The plates are not as rigid as you think. You seem to be imagining the situation as something like this: I boil an egg and take the shell off in pieces, but I can't take a piece of shell from the end and make it lay flat on the side of the egg. However, rock is not that rigid on scales of thousands of kilometres and millions of years (I don't think there exists any material which would be that rigid). Also, Earth's equatorial bulge is tiny relative to its diameter -- less than 50km. Tectonic plates move very slowly, and there is plenty of time for them to deform as they move.&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2014-04-19T17:05:31.160" LastActivityDate="2014-04-19T17:05:31.160" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="363" PostTypeId="1" CreationDate="2014-04-19T16:40:12.477" Score="22" ViewCount="326" Body="&lt;p&gt;I work a lot with numerical methods to solve multiphase flow in porous media for oil applications.  In our field, we often use Darcy's law which states that the flux is negatively proportional to the pressure gradient by a factor called the permeability.  In general, permeability is not a constant, but a tensor.  This implies that a pressure gradient in one direction may induce flow in an orthogonal direction as well.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a laboratory, permeability tensors are obtained by inducing controlled pressure gradients and measuring the resulting flow.  In an oil field, we can certainly induce pressure gradients, but it is much more difficult to control all the parameters.  Is there a way to sense a permeability field using remote sensors and geophysical inversion?&lt;/p&gt;&#xA;" OwnerUserId="154" LastEditorUserId="28050" LastEditDate="2014-11-19T12:42:42.643" LastActivityDate="2014-11-19T12:42:42.643" Title="Estimating the permeability tensor of an oil field by remote sensing" Tags="|geophysics|measurements|petroleum|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="364" PostTypeId="2" ParentId="245" CreationDate="2014-04-19T17:22:10.147" Score="5" Body="&lt;p&gt;The causes of a single particular extreme weather event, like a tornado, may never be fully understood, especially if it is a chaotic system. The causes or contributing factors to the number of tornados expected for a particular atmospheric condition is much more fully understood and is certainly not chaotic. In that sense, butterflies do not cause tornados.&lt;/p&gt;&#xA;" OwnerUserId="152" LastActivityDate="2014-04-19T17:22:10.147" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="365" PostTypeId="1" CreationDate="2014-04-19T18:16:16.630" Score="12" ViewCount="567" Body="&lt;p&gt;Most modern works (e.g. Nichols 2009; Allaby &amp;amp; Allaby 1999) seem to restrict the definition of ‘concretion’ specifically to formations in sedimentary rocks. I have recently come across a taxonomy of concretions  in Crimes (1966), which includes concretions ‘formed as a result of metamorphism’. He gives little detail about formation processes but writes that ‘[m]etamorphic concretions have also received much attention and have been reviewed briefly by Barth and Ramberg.’ (I don’t have access to the cited references.) It seems plausible to me that the concretionary processes that operate in sedimentary rock would also be possible at very low grades of metamorphism, provided that some pore space remains. However, Crimes’ concretions are apparently formed as a &lt;em&gt;result&lt;/em&gt; of metamorphism.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do such metamorphic concretions have a place in currently accepted taxonomies of sedimentary features, or have they been reclassified as a different phenomenon altogether?&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Allaby, A. &amp;amp; Allaby, A., 1999. &lt;em&gt;A dictionary of earth sciences&lt;/em&gt;, 2nd ed. Oxford University Press.  &lt;/li&gt;&#xA;&lt;li&gt;Barth, T. F. W., 1952. &lt;em&gt;Theoretical Petrology.&lt;/em&gt; New York.&lt;/li&gt;&#xA;&lt;li&gt;Crimes, T. P., 1966. The relative age of some concretions in Cambrian sediments of St. Tudwal's Peninsula, North Wales. &lt;em&gt;Geological Journal&lt;/em&gt;, 5(1), 33-42.  &lt;/li&gt;&#xA;&lt;li&gt;Nichols, G., 2009. &lt;em&gt;Sedimentology and Stratigraphy&lt;/em&gt;, 2nd ed. Wiley-Blackwell.&lt;/li&gt;&#xA;&lt;li&gt;Ramberg, H., 1952. &lt;em&gt;The origin of metamorphic and metasomatic rocks; a treatise on crystallisation and replacement in the earth’s crust.&lt;/em&gt; Chicago.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="163" LastEditorUserId="56" LastEditDate="2014-04-22T04:52:16.450" LastActivityDate="2014-11-08T11:54:24.633" Title="Can concretions form in non-sedimentary rocks?" Tags="|diagenesis|sedimentology|metamorphism|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="366" PostTypeId="2" ParentId="1" CreationDate="2014-04-19T21:36:53.587" Score="12" Body="&lt;p&gt;There's quite a bit of evidence to support that at least part of the climate system is chaotic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the &lt;a href=&quot;https://www.ipcc.ch/ipccreports/tar/wg1/504.htm&quot;&gt;IPCC&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The climate system is particularly challenging since &lt;strong&gt;it is known that&#xA;  components in the system are inherently chaotic; there are feedbacks&#xA;  that could potentially switch sign, and there are central processes&#xA;  that affect the system in a complicated, non-linear manner&lt;/strong&gt;. These&#xA;  complex, chaotic, non-linear dynamics &lt;strong&gt;are an inherent aspect&lt;/strong&gt; of the&#xA;  climate system.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There's also evidence to support this from &lt;a href=&quot;http://www.meteor.iastate.edu/gccourse/model/basic/chaos.html&quot;&gt;an Iowa State University course&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;The climate system is thought to possibly have such multiple states;&#xA;  that is, the climate (or some components of the climate system) could&#xA;  be stable for a period of time and then abruptly, and for no overtly&#xA;  evident reason, change to another stable regime.&lt;/strong&gt; There is evidence&#xA;  that certain components of the climate system have done this. The&#xA;  circulation in the north Atlantic Ocean is believed to have gone&#xA;  through an abrupt change in which the Gulf Stream, instead of tracking&#xA;  northeastward off the East Coast of the United States and heading&#xA;  toward Scandinavia, at one time switched very abruptly over about&#xA;  fifty years (that's abrupt on geological time scales) to an easterly&#xA;  direction toward the Mediterranean Sea. This caused an abrupt cooling&#xA;  of the climate in Scandinavia.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;In summary, almost-intransitivity is an inherent characteristic of the&#xA;  dynamics of the climate system that may, for seemingly small or&#xA;  unknown reasons, launch some component of the climate system into a&#xA;  pattern not previously seen.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Even more information is given in &lt;a href=&quot;http://www.giss.nasa.gov/research/briefs/hansen_03/&quot;&gt;this NASA post&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To sum all of this up: yes, at least some parts of the climate system are chaotic. But is &lt;em&gt;all&lt;/em&gt; of it chaotic? I'm not sure, but I really don't think so. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But as to the definition of a chaotic system, yes, climate is chaotic. There are definitely some things in the climate system that when changed minutely can cause everything to shift. We don't understand everything about climate right now, so it may not be truly chaotic. But as of our research right now, it is chaotic.&lt;/p&gt;&#xA;" OwnerUserId="20" LastActivityDate="2014-04-19T21:36:53.587" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="367" PostTypeId="2" ParentId="349" CreationDate="2014-04-19T22:28:08.917" Score="12" Body="&lt;p&gt;I usually tend to think that the shorter a definition is the more it introduces ambiguity and errors. So I would just think about your audience and choose an appropriate length (You  didn't mention the level you are teaching for).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similar to the definition of life you can offer to your audience characteristics, which some rocks will conform more or less. This is just a list I thought out:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Rocks are solids at the Earth's surface&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;I would definitely include solid ice, which is the primary lithology of Greenland and Antarctica&lt;/li&gt;&#xA;&lt;li&gt;How solid? Most of them are incompressible to high pressures(Exception porous sediments)&lt;/li&gt;&#xA;&lt;li&gt;With lower temperatures more things become rocks (even our Sun).&lt;/li&gt;&#xA;&lt;li&gt;Density varies greatly (bring a lead-ore and a floating tuff)&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Rocks are consolidated&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;To differentiate them from sediments rocks have underwent a certain amount of compaction and cementation&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;Rocks form through purely anorganic, organic, or a mixture of those processes&#xA;&lt;ul&gt;&#xA;&lt;li&gt;This category probably needs the most explanation on how diverse the pathways to a rocks are&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;Rocks form through natural processes&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Human-made rocks exist so instead of tossing that aside, talk about the interesting differences and similarities. Natural rocks fulfill the requirments of chemistry, physics, thermodynamics. Human-made rocks additionally fulfill requirements of pragmatism: a brick needs to be square in order to build a wall; holes make it light and insulate better; etc...&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;Anorganic rocks fall into natural categories which obey the conditions set by their chemistry and the resulting eutectic points, reduce chemical oversaturations, and minimalization of the Gibbs free energy (There is a reason why granites in all their diversity, are actually pretty similar)&lt;/li&gt;&#xA;&lt;li&gt;Organic rocks obey the requirements by organisms of which nutrients exist in excess and can be used to synthesize a skeleton or shell.&lt;/li&gt;&#xA;&lt;li&gt;Rocks don't fulfill the requirements of life&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Talk about what makes living matter special. Talk about, that on planets devoid of life everything is a rock or sediment.&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;Rocks have a scale&#xA;&lt;ul&gt;&#xA;&lt;li&gt;One atom or chemical compound is not enough to make a rock. At what scale does language speak of a rock. What scale is so big that other words are introduced. Talk about how words are also just concepts defined by other words which are concepts themselves (This is what makes science fun)&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="23" LastActivityDate="2014-04-19T22:28:08.917" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="368" PostTypeId="1" AcceptedAnswerId="462" CreationDate="2014-04-19T23:58:47.640" Score="16" ViewCount="412" Body="&lt;p&gt;Opinions abound on the web. What is the state of the current science regarding this theory and what is the best evidence? Is the theory gaining or losing traction? If it's losing what's the best of the alternatives? Perhaps there was more than one major cause. What changed peoples' minds either way pro or con?&lt;/p&gt;&#xA;" OwnerUserId="152" LastEditorDisplayName="user12525" LastEditDate="2019-04-25T08:29:22.560" LastActivityDate="2019-04-25T08:29:22.560" Title="Did the impact event that caused the Chicxulub-Crater definitively and single-handedly cause the Cretaceous-Paleogene extinction?" Tags="|geology|geophysics|paleoclimatology|paleontology|mass-extinction|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="369" PostTypeId="1" AcceptedAnswerId="456" CreationDate="2014-04-20T00:37:43.443" Score="7" ViewCount="1497" Body="&lt;p&gt;There are many factors that drive the movement of tectonic plates on the surface of asthenosphere, and some of these factors have a larger contribution than others (e.g. slab suction).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One driving factor of less significance influencing tectonic plate movement is however the Earth's rotation. Apparently one such effect of the Earth's rotation is the &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Plate_tectonics#Driving_forces_related_to_Earth_rotation&quot; rel=&quot;nofollow&quot;&gt;Pole flight force&lt;/a&gt;&quot; which results in an equatorial drift of the plates to the equator.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why does the rotation of Earth result in tectonic plates having a tendency to want to move closer to the equator?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="124" LastEditDate="2014-10-21T05:42:19.807" LastActivityDate="2015-11-16T16:28:39.503" Title="Why do tectonic plates have a tendency to drift closer to the equator?" Tags="|geophysics|plate-tectonics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="370" PostTypeId="1" AcceptedAnswerId="372" CreationDate="2014-04-20T01:45:40.273" Score="17" ViewCount="16677" Body="&lt;p&gt;The Coriolis force predicts that winds in the northern hemisphere should be deflected in a clockwise pattern and winds in the southern hemisphere should be deflected in an anti-clockwise pattern.  Why is it that in the case of cyclones however, the cyclones spin anti-clockwise in the northern hemisphere and clockwise in the southern hemisphere?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="725" LastEditDate="2014-11-30T06:23:56.827" LastActivityDate="2023-03-29T05:51:39.483" Title="Coriolis effect and Cyclones" Tags="|atmosphere|coriolis|cyclone|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="371" PostTypeId="1" AcceptedAnswerId="397" CreationDate="2014-04-20T02:54:15.613" Score="12" ViewCount="318" Body="&lt;p&gt;As mantle plumes begin in the core and move towards the crust, I would have thought that the heat in the mantle plume would disperse to the surrounding mantle, and the plume would cease to exist by the time it reaches the crust, a large distance away.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So how is the mantle plume able to survive with such a localized trajectory on its way from the core of Earth to the crust?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="28050" LastEditDate="2015-04-13T18:54:22.447" LastActivityDate="2015-04-13T18:54:22.447" Title="How do mantle plumes travel from the core of Earth to the crust?" Tags="|geophysics|volcanology|geodynamics|mantle-plumes|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="372" PostTypeId="2" ParentId="370" CreationDate="2014-04-20T07:13:49.180" Score="19" Body="&lt;p&gt;Don't think of the Coriolis force as deflecting motion clockwise/counter clockwise, but to the right (NH) or left (SH), when looking in the direction of the motion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So this is sort of 'by definition'. A cyclone is a &lt;em&gt;low&lt;/em&gt; pressure system, and air will move from a location with high pressure towards a location with low pressure. The Coriolis force will deflect this air to the right in the Northern Hemisphere, creating a counter-clockwise motion around the low pressure.&#xA;Around high pressure systems the direction of the motion is opposite, anti-cyclonic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A very simple sketch, with a low pressure in the centre, and higher pressure around it:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/CUMIs.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Another way of looking at this is through the equation for geostrophic motion. The wind around a cyclone is (nearly) geostrophic, so the equation of motion can be simplified to &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;f\mathbf{k}\times\mathbf{v} = -\frac{1}{\rho}\nabla p&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $f$ is the Coriolis parameter, $\mathbf{k}$ is the vertical unit vector, $\mathbf{v}$ is the wind speed vector, $\rho$ is density and $\nabla p$ is the pressure gradient.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, looking at a sketch of a low pressure system on the northern hemisphere, the pressure gradient force will look like&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/m8cRL.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The gradient itself goes from low to high pressure, but the force has the opposite direction. To achieve a balance between this and the Coriolis term, we need this situation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/oAxch.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Note the negative sign for the Coriolis term here. In the above equation we have equality, so with the negative sign the direction is opposite that of the pressure gradient force.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As $f$ is positive on the northern hemisphere, when we use the right-hand rule for cross-products, this means that $\mathbf{v}$ must be directed as&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/CadBM.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;i.e., giving a counter-clockwise motion around the low pressure.&lt;/p&gt;&#xA;" OwnerUserId="129" LastEditorUserId="129" LastEditDate="2014-04-25T05:54:34.383" LastActivityDate="2014-04-25T05:54:34.383" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="373" PostTypeId="2" ParentId="370" CreationDate="2014-04-20T07:15:23.993" Score="14" Body="&lt;p&gt;To correct your phrasing slightly: The Coriolis force acts to turn flows in the northern hemisphere to the right. This is not &lt;em&gt;quite&lt;/em&gt; the same as &quot;in a clockwise pattern&quot;, as will become evident in a moment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cyclones have a low pressure core and higher pressure outside. Therefore, the wind is flowing from the outside in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When we think of a cyclone, we think of a fully-formed one that has a spiral pattern. If one sets out to draw a spiral from the outside in, and bears in mind northern-hemisphere Coriolis, one curves it to the right and ends up with a clockwise spiral, which is wrong:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/UpiVA.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, a cyclone doesn't start out this way. Instead, think of a low pressure area inside a higher pressure area, so that the wind is blowing towards the centre from all directions. Draw a number of radial lines to show this... and then curve each of those to the right:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/RrEjh.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that the resulting circular motion (blue arrows) is counter-clockwise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, AIUI a cyclone doesn't quite start out that way either, but I hope that this simplified approach explains how the &quot;wrong&quot; direction of rotation could be produced.&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2014-04-21T13:10:06.127" LastActivityDate="2014-04-21T13:10:06.127" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="374" PostTypeId="2" ParentId="1" CreationDate="2014-04-20T15:07:33.163" Score="6" Body="&lt;p&gt;One problem here is the defition of &lt;em&gt;chaos&lt;/em&gt;. In the mathematical theory of dynamical systems, a system is chaotic if it contains both dense and periodic points. This is somewhat different from what one thinks &lt;em&gt;chaos&lt;/em&gt; means.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's say that by chaotic, for continuous-time dynamical systems, we mean &lt;em&gt;sensitive to initial conditions&lt;/em&gt;, i.e., that a (general, random) small perturbation of the state modifies the trajectory (future) of the system significantly. This is generally refered to as the &lt;em&gt;butterfly effect&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's been proved that, for instance, large towns have a &lt;em&gt;microclima&lt;/em&gt;, i.e., they change the local weather significantly, and that these changes know to have a significant impact on the wheather in much larger areas. This can be taken as an evidence that the system is sensitive to small perturbations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(I've taken more the &quot;mathematical chaos&quot; part of the question, the other answer by &lt;strong&gt;hichris123&lt;/strong&gt; aims more on the evidence of chaotic behaviour itself. I hope it's fine, suggestions are of course welcome.)&lt;/p&gt;&#xA;" OwnerUserId="99" LastActivityDate="2014-04-20T15:07:33.163" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="375" PostTypeId="1" AcceptedAnswerId="389" CreationDate="2014-04-20T15:34:48.577" Score="13" ViewCount="111" Body="&lt;p&gt;Periods of operation at longitude--current as well as historical. The &lt;a href=&quot;http://en.wikipedia.org/wiki/List_of_satellites_in_geosynchronous_orbit&quot;&gt;historical list on Wikipedia&lt;/a&gt; is incomplete. Is there a single site with status of &lt;strong&gt;operational&lt;/strong&gt; satellites (real-time) or do you have to go to every operator you can think of?&lt;/p&gt;&#xA;" OwnerUserId="152" LastEditorUserId="23" LastEditDate="2014-04-20T15:53:18.943" LastActivityDate="2014-04-21T15:51:42.820" Title="Does anyone know of a comprehensive listing of geostationary weather satellites?" Tags="|weather-satellites|open-data|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="376" PostTypeId="1" CreationDate="2014-04-20T15:41:37.733" Score="12" ViewCount="150" Body="&lt;p&gt;We need to store coverage areas and search by location over arbitrarily large areas. It has to be able to handle polar searches and coverage areas that span multiple hemispheres. No GIS can do this. Informix has the Geospatial Datablade, but it costs like a hundred grand. Does anyone use something more affordable--preferably free? &lt;/p&gt;&#xA;" OwnerUserId="152" LastEditorUserId="152" LastEditDate="2014-04-21T14:40:22.997" LastActivityDate="2014-04-21T14:40:22.997" Title="Does anyone know of a DBMS with global geospatial search?" Tags="|geospatial|database|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="377" PostTypeId="1" AcceptedAnswerId="3118" CreationDate="2014-04-20T15:44:59.117" Score="16" ViewCount="2155" Body="&lt;p&gt;The reason for the initiation of the El Niño is unknown, but what is well known is how it progresses once initiated.  The West Pacific warm pool begins to drift East, and the strength of the trade winds begins to decrease.  In turn, the decreased trade wind strength further enhances the drift of the warm pool to the East, and this in turn further decreases the strength of the trade winds.  It appears as though this forms a positive feedback cycle, so what is responsible for the cessation of the El Niño event?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/6Qbvy.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="111" LastEditDate="2014-12-21T21:36:50.530" LastActivityDate="2014-12-23T03:16:39.177" Title="Why does the El Niño Stop?" Tags="|ocean|climate|enso|atmospheric-circulation|climate-models|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="378" PostTypeId="2" ParentId="375" CreationDate="2014-04-20T15:51:23.487" Score="3" Body="&lt;p&gt;I queried Wikidata for &quot;instance of&quot; = &quot;weather satellite&quot; and came up with this list:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://tools.wmflabs.org/wikidata-todo/autolist.html?q=CLAIM%5b31%3A209363%2C0%3A%28%29%5d&quot; rel=&quot;nofollow&quot;&gt;http://tools.wmflabs.org/wikidata-todo/autolist.html?q=CLAIM[31%3A209363%2C0%3A%28%29]&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please remember that Wikidata still needs a huge amount of work, before queries can be judged accurate and complete (The project just started 2 years ago). If you need help improving the listing I can help you out, because I am heavily involved in Wikidata (Or coordinate your effort with the Space WikiProject: &lt;a href=&quot;https://www.wikidata.org/wiki/Wikidata%3aWikiProject_Space&quot; rel=&quot;nofollow&quot;&gt;https://www.wikidata.org/wiki/Wikidata:WikiProject_Space&lt;/a&gt;). More complex queries will be possible in the future when data density increases (the query is missing the &quot;operational status&quot; you would like to query).&lt;/p&gt;&#xA;" OwnerUserId="23" LastActivityDate="2014-04-20T15:51:23.487" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="379" PostTypeId="2" ParentId="376" CreationDate="2014-04-20T16:02:11.427" Score="7" Body="&lt;p&gt;The best open-source and free geospatial database is in my opinion PostGIS. It is easy to use and has a huge support group (also for example at  &lt;a href=&quot;https://gis.stackexchange.com/&quot;&gt;https://gis.stackexchange.com/&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It also connect to all sorts of different open-source programs and web-interfaces which should make data editing, viewing and sharing easy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It can handle the date-line and the poles:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt; 4.2.3.2.&#xA; What about the date-line and the poles?&#xA; All the calculations have no conception of date-line or poles, the coordinates are spherical (longitude/latitude) so a shape that crosses the dateline is, from a calculation point of view, no different from any other shape. &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://postgis.net/docs/manual-1.5/ch04.html#id358535&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://postgis.net/docs/manual-1.5/ch04.html#id358535&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Link: &lt;a href=&quot;http://postgis.net/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://postgis.net/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="23" LastEditorUserId="-1" LastEditDate="2017-04-13T12:33:47.360" LastActivityDate="2014-04-21T08:10:23.353" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="380" PostTypeId="1" AcceptedAnswerId="381" CreationDate="2014-04-20T16:10:30.760" Score="6" ViewCount="930" Body="&lt;p&gt;I found a rock on a beach in north-east Evia, Greece. Half is light gray, and half is dark gray. There are white (or very light gray) thin lines that form swirls throughout, crossing the light/dark gray boundary in the main body of the rock. To me, they look like fossilized leaves or something similar.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the best way to work out what this is? There seems to be an abundance of different rock types, many colors, but there are many similar stones to this one, all worn into smooth rounded pebbles.&lt;/p&gt;&#xA;" OwnerUserId="172" LastEditorUserId="2536" LastEditDate="2017-06-01T13:12:26.497" LastActivityDate="2017-06-01T13:12:26.497" Title="How can a non-geologist identify a rock?" Tags="|geology|rocks|fossils|" AnswerCount="1" CommentCount="5" ClosedDate="2014-04-22T03:29:49.337" ContentLicense="CC BY-SA 3.0" />
  <row Id="381" PostTypeId="2" ParentId="380" CreationDate="2014-04-20T16:51:29.087" Score="13" Body="&lt;p&gt;OK, so you've found yourself an interesting rock and you want to know how to identify it. I am going to go ahead and assume that you haven't studied Geology before (apologies if that's an assumption too far).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first thing you can do is to head to your local public library and find a basic &quot;rocks, minerals and fossils&quot; identification book, and try to match up what you have with something in the book. Most of these books will include some kind of description of the various tests you can do (Mohs Hardness Tests, Acid Tests, Flame tests etc).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A quick google search for the geology of the area in which you found the rock might also give you a good starting point. You are more than likely not going to find an exact match by doing this, but it will help later if you have some idea of what you might have. It also means that you will have to look at the rock critically and you'll gain far more for having tried to identify it yourself. (I work with helping ID fossils on a regular basis, and it's far more rewarding if the person who has found the fossil has some idea as to what they have, or at least a reason for their identification).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If that doesn't get you anywhere, you can turn to the internet, there are places such as the NHM's &lt;a href=&quot;http://www.nhm.ac.uk/natureplus/index.jspa&quot;&gt;Nature Plus&lt;/a&gt; where you'll find other people including experts and amateur rock hounds who might be able to give you more help. You will want to have good photographs with a scale (coins, Lens Cap, Rulers all apply).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If all else fails, Head to your local museum with a geological collection and &lt;a href=&quot;http://www.nhm.ac.uk/visit-us/galleries/red-zone/earth-lab/index.html&quot;&gt;look at the collection&lt;/a&gt;. You can also ask to speak to a geological curator and they should be able to help you identify your specimen (as your profile lists London as your location, the &lt;a href=&quot;http://www.nhm.ac.uk/visit-us/darwin-centre-visitors/marmont-centre/&quot;&gt;Natural History Museum's Angela Marmot Centre&lt;/a&gt;, &lt;a href=&quot;http://www.horniman.ac.uk/&quot;&gt;The Horniman Museum&lt;/a&gt;, or &lt;a href=&quot;https://www.bgs.ac.uk/&quot;&gt;British Geological Survey&lt;/a&gt; are all good bets).&lt;/p&gt;&#xA;" OwnerUserId="123" LastActivityDate="2014-04-20T16:51:29.087" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="382" PostTypeId="2" ParentId="70" CreationDate="2014-04-20T18:11:44.893" Score="6" Body="&lt;p&gt;To build on Drew's excellent answer, I would note the following:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Weather forecasts of the &lt;strong&gt;future&lt;/strong&gt; are built on &lt;strong&gt;historical&lt;/strong&gt; frequencies. A &quot;forecast&quot; of a X percent chance of rain (however defined), means, based on the current configuration of casual variables (temperature, humidity, air pressure etc.), there has historically been an X per cent chance of rain in 24 hours. Therefore, we forecast X percent for tomorrow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sometimes a forecaster will try to incorporate unusual events into the equation. (&lt;a href=&quot;http://en.wikipedia.org/wiki/Chernobyl_disaster&quot; rel=&quot;noreferrer&quot;&gt;Chernobyl&lt;/a&gt; comes to mind.) Then the argument might be, historically the chances of rain were X percent, but we're bumping up the forecast to y percent, because of all the atomic particles released by Chernobyl.&lt;/p&gt;&#xA;" OwnerUserId="42" LastActivityDate="2014-04-20T18:11:44.893" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="384" PostTypeId="1" CreationDate="2014-04-20T20:18:24.497" Score="10" ViewCount="411" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Floral transformations have been due to gradual replacement and&#xA;  piecemeal, not mass extinction. Plant “geoevents”; have not been&#xA;  synchronous with epochal animal originations/ extinctions and hence&#xA;  may not be attributable to the same causes.&#xA;  -&lt;a href=&quot;http://www.tandfonline.com/doi/abs/10.1080/08912968809386480?journalCode=ghbi20#.U1QqXvldWT8&quot;&gt;Traverse (1988)&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What evidence is preserved in the fossil record to support that the terrestrial plants were largely unaffected by Mass Extinction events? And what does this tell us about possible Mass Extinction scenarios? &lt;/p&gt;&#xA;" OwnerUserId="140" LastEditorUserId="140" LastEditDate="2014-04-21T15:34:29.377" LastActivityDate="2014-05-19T12:33:14.690" Title="What evidence is there that plant evolutionary history &quot;dances to a different beat&quot; than that of animals?" Tags="|paleontology|paleobotany|mass-extinction|evolution|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="385" PostTypeId="2" ParentId="376" CreationDate="2014-04-20T22:01:11.923" Score="4" Body="&lt;p&gt;I agree with Speissburger that PostGIS (an extension of Postgre) has excellent Geospatial support. In the open source world, this would also be my recommendation.&#xA;(MySQL claims to have some geospatial support but it is very limited in capabilities)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For completeness, Microsoft's SQL Server also has good geospatial support - I think it was introduced as an extension to SQL Server 2008, and then standard after that.&#xA;I have heard that Oracle also has good geospatial support, although I have never use it.&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2014-04-20T22:01:11.923" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="386" PostTypeId="2" ParentId="293" CreationDate="2014-04-21T09:53:28.927" Score="9" Body="&lt;p&gt;&lt;em&gt;Keep in mind that although I am a paleontologist, I am not a vertebrate paleontologist so I might not be aware of every single find ever made of feathered dinosaur.&lt;/em&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as I can tell, all dinosaurs fossils exhibiting feathers belong to the Theropoda. Here is a (probably dated) phylogeny of dinosaurs from &lt;strong&gt;Sereno 1999&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/GxsO1.jpg&quot; alt=&quot;Phylogeny of Dinosaurs by Paul Sereno, 1999, published in Science.&quot;&gt;&#xA;&lt;sub&gt;Credit: Paul C. Sereno&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Theropoda is the group from &lt;em&gt;Eoraptor&lt;/em&gt; to Euornithes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;While &lt;em&gt;Eoraptor&lt;/em&gt;  is Triassic, the group diversifies mostly during the Jurassic (still &lt;strong&gt;Sereno 1999&lt;/strong&gt;) and it is also during that time that we start having &quot;common&quot; feathered dinosaur fossil evidence (e.g. &lt;strong&gt;Zhang et al. 2008, Sullivan et al. 2014&lt;/strong&gt;).&lt;br&gt;&#xA;Birds (Aves) seem to have appeared in the late Jurassic / early Cretaceous as well, but modern birds (Neornithes), i. e. birds with living representative, appeared only in the late Cretaceous.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know of any proper (sample-standardized, with coherent bias detection and removal) paleodiversity study for the theropods, although there is one for Aves (&lt;strong&gt;Brocklehurst et al. 2012&lt;/strong&gt;), so it's hard to discuss about it at a species level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In theory, feathers are more likely to fossilize than other soft tissue (&lt;strong&gt;Davis &amp;amp; Briggs 1995&lt;/strong&gt;) but in practice they are mostly found in finely grained sediments such as limestones, thus limiting the amount of outcrops in which they can be found.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Sources:&lt;br&gt;&#xA;Brocklehurst, N., Upchurch, P., Mannion, P. D., O'Connor, J., 2012. &lt;a href=&quot;http://dx.doi.org/10.1371/journal.pone.0039056&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Completeness of the Fossil Record of Mesozoic Birds: Implications for Early Avian Evolution&lt;/a&gt;. PLoS ONE 7(6): e39056.&lt;br&gt;&#xA;Davis, P. G., Briggs, D. E. G., 1995. &lt;a href=&quot;http://geology.gsapubs.org/content/23/9/783.short&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fossilization of feathers.&lt;/a&gt; Geology, 23(9): 783-786.&lt;br&gt;&#xA;Sereno, P., 1999. &lt;a href=&quot;http://dx.doi.org/10.1126/science.284.5423.2137&quot; rel=&quot;nofollow noreferrer&quot;&gt;The evolution of Dinosaurs.&lt;/a&gt; Science, 284: 2137-2147.&lt;br&gt;&#xA;Sullivan, C. &lt;em&gt;et al.&lt;/em&gt; 2014. &lt;a href=&quot;http://dx.doi.org/10.1080/02724634.2013.787316&quot; rel=&quot;nofollow noreferrer&quot;&gt;The vertebrates of the Jurassic Daohugou Biota of northeastern China.&lt;/a&gt; Journal of Vertebrate Paleontology, 34: 243-280.&lt;br&gt;&#xA;Zhang, F. &lt;em&gt;et al.&lt;/em&gt;  2008. &lt;a href=&quot;http://dx.doi.org/10.1038/nature07447&quot; rel=&quot;nofollow noreferrer&quot;&gt;A bizarre Jurassic maniraptoran from China with elongate ribbon-like feathers.&lt;/a&gt; Nature, 455: 1105-1108.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-11-20T13:29:48.103" LastActivityDate="2014-11-20T13:29:48.103" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="387" PostTypeId="2" ParentId="213" CreationDate="2014-04-21T10:30:50.997" Score="6" Body="&lt;p&gt;I'm not sure if it's correct to say that El Niño enhances the jet stream, reading &lt;a href=&quot;http://www.srh.noaa.gov/jetstream/tropics/enso_impacts.htm&quot;&gt;NWS&lt;/a&gt;&#xA;they seem to state that the affect is more of a shift in the position of the jet stream over the Pacific and North America. I guess any enhancement would be due to a greater temperature contrast between the poles and equator.&lt;/p&gt;&#xA;" OwnerUserId="140" LastActivityDate="2014-04-21T10:30:50.997" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="388" PostTypeId="1" CreationDate="2014-04-21T12:32:21.443" Score="18" ViewCount="9088" Body="&lt;p&gt;George Hadley's initial model of the Hadley cell described air as being heated at the equator, ascending, and then moving aloft pole-wards where it would cool and descend.  Meanwhile surface air would move towards the equator to take the place of the rising hot air there, forming a giant Hadley cell, as in the picture below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/4VBsc.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However the modern conception of the Hadley cell is one where air ascends at the equator while air at an angle of 30° latitude descends, with winds moving towards the equator on the surface, and with winds moving towards the poles aloft to complete the cell.  The modern conception of the Polar cell also works in the same manner, with the difference being that the expanding air hot air in this cell originates from 60° latitude, rather than from the equator.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/VBfjd.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is it that the air in the Hadley cell descends at 30° latitude, as opposed to continuing all the way to the poles as Hadley had initially suggested, and why does air then rise again at 60° latitude forming the Polar cell?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="2470" LastEditDate="2023-11-14T18:24:50.733" LastActivityDate="2023-11-14T18:24:50.733" Title="Why does the Hadley cell descend at 30 degrees latitude?" Tags="|meteorology|atmospheric-circulation|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="389" PostTypeId="2" ParentId="375" CreationDate="2014-04-21T14:36:52.027" Score="12" Body="&lt;p&gt;The &lt;a href=&quot;http://www.wmo-sat.info/oscar/satellites&quot; rel=&quot;noreferrer&quot;&gt;WMO OSCAR&lt;/a&gt; database is a list of &lt;em&gt;all&lt;/em&gt; Earth observation satellites¹.  The resulting table can be sorted by orbit type, status (inactive/operation/planned), agency, and other aspects.  From their own description:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This table shows all known past, current and future satellites for meteorological and earth observation purposes.It can be sorted by clicking on the column headers. The filter on the right allows to display only specific satellites.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A screenshot showing three GOES satellites and the scroll-bar on the right is shown below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/sw2NC.png&quot; alt=&quot;OSCAR SATS screenshot&quot;&gt;&#xA;&lt;br /&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that OSCAR has a lot more capabilities than this.  For anything Earth-observation-from-space related, it is a superb resource.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;¹Except classified (spy) satellites...&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2014-04-21T15:51:42.820" LastActivityDate="2014-04-21T15:51:42.820" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="390" PostTypeId="2" ParentId="363" CreationDate="2014-04-21T15:45:48.730" Score="12" Body="&lt;p&gt;I remember a comment on this by Rodney Calvert in the video lecture version of his SEG Distinguished Instructor Lecture &quot;Insights and Methods for 4D Reservoir Monitoring and Characterization&quot;:&#xA;&lt;a href=&quot;http://shop.seg.org/OnlineStore/ProductDetail/tabid/177/Default.aspx?ProductId=1842&quot;&gt;http://shop.seg.org/OnlineStore/ProductDetail/tabid/177/Default.aspx?ProductId=1842&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The comment was referring to the possibility of observing a pressure change front moving through the reservoir (as opposed to a fluid staturation change front) if one were to perform very closely repeated time lapse seismic surveys (down to probably days instead of months between surveys) AND in the very early stages of development. Costly of course but it would allow far superior well placement in complex reservoirs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's some reference to this in Chapter 2 of the book:&#xA;&lt;a href=&quot;http://library.seg.org/doi/book/10.1190/1.9781560801696&quot;&gt;http://library.seg.org/doi/book/10.1190/1.9781560801696&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;but if I recall, the comment in the video lecture was far more specific. It is worht a try, the course is great to take anyways.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;UPDATE&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Following comments below and a review of some reference material.&#xA;The problem of permeability is that this is a multiscale property. You get different estimates (and different relationships, for example to porosity) at different scales (e.g. pore, lamina, bed, geobody, formation, and reservoir scales). The challenge is to link permeability at all scales and it is compound mainly by two facts: 1) at some scales you measure permeability statically, at other scales dynamically; and 2) at some scales permeability is not well captured/represented by any measurement (for example bedset scale, which is larger than core scale but often not well captured by wireline log data).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My advice to you would be to get this book by Patrick Corbett, the go-to guy in the field: &lt;a href=&quot;http://library.seg.org/doi/book/10.1190/1.9781560801597&quot;&gt;http://library.seg.org/doi/book/10.1190/1.9781560801597&lt;/a&gt;. It is about 90 pages and it guides you through the whole process, with measurements, modeling, testing at all scales, topped by an excellent example of integration at all scales in chapter 6. I worked through the book and several of the reference papers 3 years ago, for personal knowledge, and it was great.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From a quick review last night I'd say one very important tool is Petrotyping, as defined in the book. The full work is in reference paper Corbett and Potter, 2004, Society of Core Analysts paper SCA2004-30. This paper defines Hydraulic Units as representative volume elements where geological, petrophysical, hydraulic properties are predictable and different from those in other units. Each unit is defined by a Flow Zone Indicator (FZI) (defined in the paper). A relationship is intorduced in the paper relating permeability to porosity via FZI. With this relationship a set of lines of constant FZI can be used as a template in a porosity (decimal) - permeability (log) plot to assess Global Hydraulic Elements in the reservoir. A Global Hydraulic Element is an element where the relationship between porosity and permeability is unique. If you are lucky your reservoir (for example a chalk reservoir, one of the examples in Corbett's book) has a single Global Hydraulic Element, in essence a single rock type of uniform properties. In this case you could go relatively easily from a static geomodel of reservoir facies modeled at the reservoir scale (and constrained with seismic inversion for acoustic impedance or porosity, ideally stochastically) to permeability at the scale of your lab measurements - you would be using also well tests (drill stem tests, production tests) and Lorentz plots. In the case of a developed field you may also integrate dynamic simulations and time laps (4D) seismic data (linekd to saturation and/or geomechanic changes introduced  in the reservoir by production).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If there are multiple GHEs, then the work of predicting at core plug scale, upscaling, validating with dynamic testing, and extending to the reservoir scale is more complicated (but still possible). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I really recommend the book.&lt;/p&gt;&#xA;" OwnerUserId="144" LastEditorUserId="144" LastEditDate="2014-04-23T14:46:10.617" LastActivityDate="2014-04-23T14:46:10.617" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="391" PostTypeId="1" CreationDate="2014-04-21T16:37:44.740" Score="22" ViewCount="3458" Body="&lt;p&gt;I've heard that gold ore is often associated with quartz veins.  What geological processes enable gold particles to naturally cluster together like this? What characteristics/properties should I look out for on the surface of a rock that are likely to yield gold within it? Are there remote sensors that I use to detect the presence of gold in a rock?&lt;/p&gt;&#xA;" OwnerUserId="154" LastEditorDisplayName="user12525" LastEditDate="2019-04-18T13:44:57.273" LastActivityDate="2019-04-18T13:44:57.273" Title="In what geological situations can I find gold?" Tags="|geology|mineralogy|economic-geology|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="392" PostTypeId="2" ParentId="365" CreationDate="2014-04-21T17:38:06.183" Score="7" Body="&lt;p&gt;Not really. Concretions are features of sedimentary rocks almost by definition. Here's my go at a definition; it essentially presupposes a sedimentary rock:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Concretions&lt;/strong&gt; are spatially discrete zones of above-average (compared to the rest of the rock) cementation by authigenic minerals. Common cements include calcite, quartz, siderite, and pyrite.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Concretions form during the process of &lt;a href=&quot;https://en.wikipedia.org/wiki/Diagenesis&quot; rel=&quot;nofollow&quot;&gt;diagenesis&lt;/a&gt;. However, diagenesis and metamorphism are really on a continuum of 'burial effects' — increasing temperature and pressure, compaction, changing porewater chemistry, and so on. One could almost call diagenesis a &lt;a href=&quot;https://en.wikipedia.org/wiki/Metamorphism#Metamorphic_facies&quot; rel=&quot;nofollow&quot;&gt;metamorphic facies&lt;/a&gt;. Concretions can start to form immediately after burial, and grow during burial as long as geo- and electro-chemical conditions allow, or until the pores are completely occluded. According to some workers (e.g. Bjoerkum &amp;amp; Walderhaug), total occlusion usually happens somewhere between about 150 °C and 200 °C. By this time, clay minerals have started altering and we are into low-grade metamorphism (&lt;a href=&quot;https://en.wikipedia.org/wiki/Zeolite_facies&quot; rel=&quot;nofollow&quot;&gt;zeolite facies&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Conversely, I think most so-called soft-rock geologists just lump all alteration into 'diagenesis' (I know I did until I started working on geothermal reservoirs). So, if you're prepared to explain yourself because it sounds weird, you could claim that concretions form in metamorphic rocks. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Footnotes&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;I've never seen one, but I don't see why you couldn't have concretions in volcaniclastic rocks (which I count as sufficiently like sedimentary rocks to warrant no more than a footnote).&lt;/li&gt;&#xA;&lt;li&gt;If you were desperate to call something else a concretion — a mass of phenocrysts in a granite, say — you could always broaden your definition of 'concretion'. We geologists love arguing about the definitions of words!&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="725" LastEditDate="2014-11-08T11:54:24.633" LastActivityDate="2014-11-08T11:54:24.633" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="393" PostTypeId="1" AcceptedAnswerId="409" CreationDate="2014-04-21T18:38:32.637" Score="11" ViewCount="913" Body="&lt;p&gt;Organic walled microfossils have no hard mineralised parts, how are they preserved in the fossil record?&lt;/p&gt;&#xA;" OwnerUserId="140" LastEditorUserId="140" LastEditDate="2014-04-21T18:56:52.843" LastActivityDate="2014-08-20T07:19:23.900" Title="How are organic walled microfossils preserved in the fossil record?" Tags="|paleontology|taphonomy|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="394" PostTypeId="5" CreationDate="2014-04-21T18:44:54.597" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-21T18:44:54.597" LastActivityDate="2014-04-21T18:44:54.597" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="395" PostTypeId="4" CreationDate="2014-04-21T18:44:54.597" Score="0" Body="Paleontology (also Palaeontology) is the scientific study of past life. Questions about the biological aspect of paleontology (such as taxonomy and anatomy) are off-topic here and should be asked on biology.stackexchange.com" OwnerUserId="140" LastEditorUserId="87" LastEditDate="2014-04-22T13:51:49.170" LastActivityDate="2014-04-22T13:51:49.170" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="397" PostTypeId="2" ParentId="371" CreationDate="2014-04-21T20:15:30.540" Score="9" Body="&lt;p&gt;The high values obtained when estimating the Rayleigh number for the mantle indicates that convection there is vigorous, and that convection is responsible for almost all the heat transported from the deep interior to the surface. Similar systems set up in the laboratory can develop 'plume-like' patterns of convective flow, and so mantle plumes are a physically plausible model of mantle convection too.   &lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-04-21T20:15:30.540" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="399" PostTypeId="2" ParentId="352" CreationDate="2014-04-21T22:57:17.623" Score="8" Body="&lt;p&gt;You can automatically detect the P and S waves for an event but I don't know of a way to automatically extract the Rayleigh and Love waves directly from the seismograms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As @kwinkunks points out things are complicated in the real world. Understanding an event is an iterative bootstrapping process that is best done by looking at  recordings from several stations and preferably with multi-component recordings. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My experience is with regional scale earthquake seismology where the signal amplitude is also a powerful discriminator - the fast, low amplitude P wave arrives first. Then the slower, higher amplitude S wave comes in later. You can see this happening on the seismogram that you originally linked to or you can watch this somewhat relevant &lt;a href=&quot;https://www.youtube.com/watch?v=1MFzcl-kZHo&quot;&gt;video of a dog&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="8" LastEditorUserId="8" LastEditDate="2014-04-25T16:20:06.100" LastActivityDate="2014-04-25T16:20:06.100" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="400" PostTypeId="1" AcceptedAnswerId="401" CreationDate="2014-04-21T23:47:47.947" Score="51" ViewCount="6561" Body="&lt;p&gt;Most of us know about the Dust Bowl: the huge storms of dirt and dust that swept across America in the 1930's. But what I'm wondering is... &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;What actually triggered the start of the Dust Bowl?&lt;/li&gt;&#xA;&lt;li&gt;Is it very likely that it will occur again?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I've often heard that it was the farmers plowing up to much soil, but that doesn't make any sense to me because we're definitely plowing up more soil now than we were then.&lt;/p&gt;&#xA;" OwnerUserId="115" LastEditorUserId="2470" LastEditDate="2015-04-30T08:14:47.657" LastActivityDate="2017-05-23T22:24:54.783" Title="What started the US Dust Bowl of the 1930s, and could it happen again?" Tags="|climate|soil|dust-bowl|" AnswerCount="5" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="401" PostTypeId="2" ParentId="400" CreationDate="2014-04-22T00:49:11.637" Score="47" Body="&lt;p&gt;The Dustbowl occurred during the 1930s because of a combination of man-induced drought and the (mis)use of relatively new farming practices.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the 1920s, the spread of automotive (and tractor) technologies made it possible to &quot;plow up&quot; the Great Plains. This resulted in the loss of a lot of natural moisture and the creation of drought conditions in lands that had been marginal to begin with regarding the adequacy of the water supply. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even by the 1930s we &lt;em&gt;still&lt;/em&gt; had not learned our lesson. There were conservation techniques using the new technologies, but we weren't using them. For example, the tractors would still plow up and down slopes (the &quot;easy&quot; way) making it easy for topsoil to run down hills and into the rivers. More to the point, the newly dry and loosened topsoil would then go into the air and create a &quot;Dust Bowl&quot; when the winds kicked up. There was a real fear that the agricultural Midwest (basically the Plains states) would turn into a desert.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It was only after an additional half a decade of bitter trial and error (and a new generation of better educated farmers) that things changed. By the &lt;strong&gt;mid&lt;/strong&gt; 1930s, it was a relatively new technique called &lt;a href=&quot;http://en.wikipedia.org/wiki/Contour_plowing&quot;&gt;contour farming&lt;/a&gt;, which consisted of using motor vehicles to plow horizontally around hills instead of vertically, that saved the day. Also, farmers started planting trees as &quot;windbreaks&quot; in strategic locations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;IMHO, it could happen again, probably in a developing country like China, which is trying to &quot;catch up&quot; to the United States, and has been prone to adopting our bad habits of an earlier era.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bottom line, the Dust Bowl was (largely) a man-made, not a natural phenomenon. And the operative principle was attributed to Confucius: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Men are the same everywhere. Only their habits are different.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="42" LastEditorUserId="42" LastEditDate="2014-09-22T13:47:03.853" LastActivityDate="2014-09-22T13:47:03.853" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="402" PostTypeId="1" AcceptedAnswerId="748" CreationDate="2014-04-22T00:57:11.700" Score="12" ViewCount="4265" Body="&lt;p&gt;Is it true that Earth's outercore rotates in the opposite direction to Earth's inner-core?  Is there a plausible explanation for why this phenomenon occurs and what is the available evidence supporting this notion?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="87" LastEditDate="2014-04-23T11:47:33.550" LastActivityDate="2014-05-03T23:18:30.267" Title="Why does Earth's outer-core rotate in the opposite direction to the inner-core?" Tags="|geophysics|geodynamics|core|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="403" PostTypeId="1" CreationDate="2014-04-22T01:27:38.030" Score="13" ViewCount="253" Body="&lt;p&gt;Earth's core mantle boundary represents a phase change from a solid (though convecting) mantle to a liquid Iron/Nickel core. This dramatic transition is likely the origin of the D&quot; boundary, as well as thermodynamic perturbations and deep mineral heterogeneities in the mantle, which cause tectonic features on Earth's surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is well documented that &lt;a href=&quot;http://en.wikipedia.org/wiki/Europa_%28moon%29&quot;&gt;Europa&lt;/a&gt; and &lt;a href=&quot;http://en.wikipedia.org/wiki/Enceladus&quot;&gt;Enceladus&lt;/a&gt; have subsurface oceans, which represents a phase change inside the satellite's interior. Is this phase change responsible for the &lt;a href=&quot;http://en.wikipedia.org/wiki/Chaos_terrain&quot;&gt;chaos terrain&lt;/a&gt;  on Europa, the &lt;a href=&quot;http://en.wikipedia.org/wiki/Tiger_stripes_%28Enceladus%29&quot;&gt;Tiger Stripes&lt;/a&gt; and &lt;a href=&quot;http://en.wikipedia.org/wiki/Cryovolcano&quot;&gt;volcanism&lt;/a&gt; on Enceladus? Or do these tectonic features originate from exterior forces, such as gravitational tides and bombardments from Jupiter/Saturn's magnetosphere?  &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="51" LastEditDate="2014-04-22T02:04:49.270" LastActivityDate="2016-05-12T09:59:18.240" Title="Phase changes deep in planetary interiors and their implications for surface tectonics" Tags="|geophysics|oceanography|geodynamics|planetary-science|tectonics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="404" PostTypeId="2" ParentId="402" CreationDate="2014-04-22T03:00:52.027" Score="4" Body="&lt;p&gt;The earth's core may rotate at a faster rate, not in the opposite direction, this would be consistent with heavier elements sinking to form the core during planetary differentiation. Conservation of angular momentum could cause it to rotate faster. See this question in Physics SE.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://physics.stackexchange.com/questions/68677/what-is-the-evidence-for-the-super-rotation-of-earths-inner-core&quot;&gt;What is the evidence for the super-rotation of the earth's core?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorUserId="-1" LastEditDate="2017-04-13T12:40:15.470" LastActivityDate="2014-04-22T03:00:52.027" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="405" PostTypeId="2" ParentId="344" CreationDate="2014-04-22T03:09:45.547" Score="9" Body="&lt;p&gt;I wouldn't characterize the movement of the jetstream as a &quot;less well known&quot; problem, at least not to anyone who has sat through a synoptic meteorology class.  The jetstream from a dynamic point of view is just an enhanced gradient in the heights on a constant pressure surface (or pressures on a constant height surface) and there are many factors the influence this gradient.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, lets take a look at the northern hemisphere 500 mb heights and surface pressure:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZBvys.gif&quot; alt=&quot;height anomaly&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What we see here is in the mid-latitude storm track we have a series of highs and lows on the 500 mb surface (blues are low anomalies, red high anomalies).  This particular pattern look to be wavenumber 7,  This is a planetary rossby wave. If the weather was frozen in place and all external factors eliminated, the wavenumber is going to dictate how fast this pattern rotates around the globe.  For low wavenumbers, this pattern will even move retrograde, but that is not something you see often (if memory serves, this is wavenumber 3 and lower).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might wonder why I'm talking about waves at 500 mb when the polar jetstream is up a bit higher between 250 and 300 mb, varying seasonally.  The pattern of highs and lows is evident throughout the troposphere.  You can see it reflected in the surface pressure and in the image below you can see it in the 300 mb pattern.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/xCXgq.png&quot; alt=&quot;300 mb&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far we've mentioned that the wavenumber of the planetary wave has an influence on movement of the pattern, but what about how the pattern evolves?  There are a lot of factors here:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Oceans&lt;/li&gt;&#xA;&lt;li&gt;Mountains&lt;/li&gt;&#xA;&lt;li&gt;Surface heating&lt;/li&gt;&#xA;&lt;li&gt;Convection&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;And perhaps the biggest: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;mid-latitude cyclones.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Part of cyclone self development is a positive feedback between surface temperature advection and pressure changes at the tropospheric mid levels.  As the cyclone matures the advancing surface cold front will correlate with low 500 mb heights and lower 300 mb heights.  This response will perturb where the jetstream lies and indeed, the jetstream tends to lie over the fronts extending from a mid-latitude cyclone.  If you conceptualize the fronts from one cyclone extending back and forward to the cyclones next to it, this is the &quot;polar front&quot; and gives you a rough idea of where the jetstream is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An additional factor in how the jetstream propagates is the particular shape of the jetstream.  There are a number of blocking patterns (e.g. Omega block, Rex block) that tend to persist as a stationary feature once setup.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, remember that in an atmospheric column, pressure is just the weight of all the air above a height, and anything that can modify the column (e.g. surface heating, cooling, mid-level changes) can modify the 300mb heights and subsequently affect the positioning of the jetstream.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-04-22T03:09:45.547" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="406" PostTypeId="2" ParentId="403" CreationDate="2014-04-22T03:51:36.897" Score="7" Body="&lt;p&gt;The tiger stripes of Enceladus are thought to be a result of this moon's unusual chemical composition, as opposed to any mineral heterogeneity or thermodynamic perturbations occurring due to the phase change near the rocky core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/agdwH.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ammonia has been found indirectly to exist on Enceladus and the unique ammonia-water composition of Enceladus is thought to give rise to the cracks in the tectonic plates on the surface, which we know as the &quot;tiger stripes&quot;.  Enceladus began as a frozen shell of an ammonia and water ice mixture surrounding a rocky core.  Through interaction with other moons, heat was generated above the rocky silicate core, resulting in the ice shell separating into an ammonia-enriched liquid layer directly on top of the core, and a thin layer of ice (water) above it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0019103509001286&quot; rel=&quot;nofollow noreferrer&quot;&gt;Research&lt;/a&gt; by Dr Dave Stegman, a Centenary Research Fellow in the School of Earth Sciences at the University of Melbourne, has found that if the water ice formed near the core, then it would give rise to the &quot;tiger stripes&quot; which are thought to be cracks caused by tectonic activity on the south pole of the moon's surface&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;We found that if a layer of pure water ice formed near the core, it&#xA;  would have enough buoyancy to rise upwards, and such a redistribution&#xA;  of mass can generate large tectonic stresses at the surface,&quot; &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&quot;However, the pure water ice rising up is also slightly warmer which&#xA;  causes the separation to occur again, this time forming an&#xA;  ammonia-enriched ocean just under the surface. The presence of&#xA;  ammonia, which acts as an anti-freeze, then helps keep the ocean in&#xA;  its liquid state.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So in this case, while one could say that the boundary may have played a role, it is certainly not analogous to the role the phase transition plays in the formation of features on Earth's surface.  The linked paper provides more details as to how the ammonia-water composition can give rise to the observed terrain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regards to the chaotic terrain of Europa, it is an active area of research and is very poorly understood.  No model so far has been able to explain why features such as Conamara Chaos stand above surrounding terrain and contain matrix domes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;http://www.nature.com/ngeo/journal/v7/n1/full/ngeo2021.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;one paper&lt;/a&gt; however,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We conclude that Europa's ocean dynamics can modulate the exchange of&#xA;  heat and materials between the surface and interior and explain the&#xA;  observed distribution of chaos terrains.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It therefore seems unlikely given current research that the chaotic terrain of Europa is a result of a phase change boundary.&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="56" LastEditDate="2014-04-23T02:10:37.627" LastActivityDate="2014-04-23T02:10:37.627" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="407" PostTypeId="2" ParentId="402" CreationDate="2014-04-22T04:42:24.650" Score="8" Body="&lt;p&gt;The answer is that there are more forces than just the momentum of the earth at play. The electromagnetic force generated by the core is pushing on itself, in fact:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;The fact that Earth's internal magnetic field changes slowly, over a timescale of decades, means that the electromagnetic force responsible for pushing the inner and outer cores will itself change over time. This may explain fluctuations in the predominantly eastwards rotation of the inner core, a phenomenon reported for the last 50 years by Tkalčić et al. in a recent study published in Nature Geoscience.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;from &lt;a href=&quot;http://www.sciencedaily.com/releases/2013/09/130916162005.htm&quot; rel=&quot;noreferrer&quot;&gt;http://www.sciencedaily.com/releases/2013/09/130916162005.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You see, these changes in the internal portions in the Earth's magnetic field cause a shear.  The Earth's magnetic poles are not stationary, they wander. There is clear evidence of this from the paleomagnetic record. This is caused by the viscous convection of the iron nickel outer core. Their numerical models showed that the electromagnetic torque :&#xA;&lt;img src=&quot;https://i.stack.imgur.com/uznwp.gif&quot; alt=&quot;enter image description here&quot;&gt; from P.W. Livermore et al. 2013&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the outer core has a westward direction, while the inner core's torque scales accordingly in the opposite direction. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/rsXl8.gif&quot; alt=&quot;&quot;&gt;&#xA; from P.W. Livermore et al. 2013&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally a cross section (image above) of the asymmetric flow (off dipole) clearly shows opposite direction in the outer core and inner core (blue vs red on the color bar).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, in summary:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The electromagnetic field is modeled as a dipole, but in actuality has ~10% component that is off the dipole.&lt;/li&gt;&#xA;&lt;li&gt;The wandering of this dipole (and by consequence, off dipole) magnetic field causes a shear in opposite directions at the inner and outer core.&lt;/li&gt;&#xA;&lt;li&gt;This inner and outer core shear scales similarly at the edges (at the inner core outer boundary and at the core mantle boundary) but in opposite directions (so they are of the same magnitude).&lt;/li&gt;&#xA;&lt;li&gt;This torque, causes the flow of the inner core and the outer core to spin in opposite directions, as shown by the last figure.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;This is a complex article, let me know if there is anything I could explain better. I think I've got this right. &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-04-22T04:42:24.650" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="408" PostTypeId="2" ParentId="170" CreationDate="2014-04-22T05:33:00.697" Score="20" Body="&lt;p&gt;For very quick visual comparison I would use &lt;a href=&quot;http://scitools.github.io/cube_browser&quot; rel=&quot;nofollow&quot;&gt;Cube Browser&lt;/a&gt; or &lt;a href=&quot;http://meteora.ucsd.edu/~pierce/ncview_home_page.html&quot; rel=&quot;nofollow&quot;&gt;ncview&lt;/a&gt; together with a command line tool like the &lt;a href=&quot;https://code.zmaw.de/projects/cdo/wiki&quot; rel=&quot;nofollow&quot;&gt;Climate Data Operators&lt;/a&gt;. For quick production of nice looking graphics (and animations) &lt;a href=&quot;http://www.giss.nasa.gov/tools/panoply/&quot; rel=&quot;nofollow&quot;&gt;Panoply&lt;/a&gt; really makes good job. For further analysis or special graphics keep following your approach and script with things like &lt;a href=&quot;http://www.mathworks.com/products/matlab&quot; rel=&quot;nofollow&quot;&gt;MATLAB&lt;/a&gt;, &lt;a href=&quot;https://www.python.org/&quot; rel=&quot;nofollow&quot;&gt;Python&lt;/a&gt; (e.g. with &lt;a href=&quot;http://scitools.org.uk/iris/&quot; rel=&quot;nofollow&quot;&gt;Iris&lt;/a&gt;), &lt;a href=&quot;http://www.exelisvis.com/IDL&quot; rel=&quot;nofollow&quot;&gt;IDL&lt;/a&gt;, &lt;a href=&quot;https://www.r-project.org&quot; rel=&quot;nofollow&quot;&gt;R&lt;/a&gt;, &lt;a href=&quot;https://www.ncl.ucar.edu/&quot; rel=&quot;nofollow&quot;&gt;ncl&lt;/a&gt; or whatever people around you are using.&lt;/p&gt;&#xA;" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2016-06-15T17:35:22.663" LastActivityDate="2016-06-15T17:35:22.663" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="409" PostTypeId="2" ParentId="393" CreationDate="2014-04-22T07:07:21.683" Score="11" Body="&lt;p&gt;Organic-walled microfossils (wether they be dinoflagellates, pollens, spores or &quot;acritarchs&quot;)  all have in common to contain an organic compound known as sporopollenin (for the spores and pollens) or dinosporin (for dinoflagellates and, I believe, acritarchs as well). Both compounds have chemical and structural similarities but have appeared independently. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Those compound are incredibly resistant. To give you an idea, to collect siliceous microfossils we first dissolve the sediments with HCl (hydrochloric acid) to get rid of carbonate microfossils. Palynologists (who study such organic-walled microfossils) uses HF (hydrofluoric acid) to get rid of both carbonate and siliceous microfossils (e.g. &lt;strong&gt;Doher 1980&lt;/strong&gt;). Sporopollenin therefore resist to HF, which has a pH of ca. 3. In addition to this, they are also unusually resistant to microbiological degradation (e. g. &lt;strong&gt;Gunnison &amp;amp; Alexander 1975&lt;/strong&gt;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;They are however not resistant to oxydation, hence, probably, why we don't find more of them in the sediments. Additionally, to break sporopollenin walls (in order to study the inner side of those walls) ultrasound can be used (e. g. &lt;strong&gt;Lennie 1968&lt;/strong&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Organic-walled&quot; doesn't mean no hard part, it just means no &quot;mineral&quot; hard part.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Sources:&lt;br&gt;&#xA;Doher, I., 1980. &lt;a href=&quot;http://pubs.usgs.gov/circ/1980/0830/report.pdf&quot; rel=&quot;nofollow&quot;&gt;Palynomorph preparation procedures currently used in the paleontology and stratigraphy laboratories, U.S. Geological Survey&lt;/a&gt;. Geological Survey circular, 830: 1-29.&lt;br&gt;&#xA;Gunnison, D., Alexander, M., 1975. &lt;a href=&quot;http://aem.asm.org/content/29/6/729.full.pdf&quot; rel=&quot;nofollow&quot;&gt;Basis for the resistance of several algae to microbial decomposition&lt;/a&gt;. Applied Microbiology, 29: 729-738.&lt;br&gt;&#xA;Lennie, C. R., 1968. &lt;a href=&quot;http://dx.doi.org/10.1080/00288306.1968.10420254&quot; rel=&quot;nofollow&quot;&gt;Palynological Techniques used in New Zealand&lt;/a&gt;. New Zealand Journal of Geology and Geophysics, 11: 1211-1221.&#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;At the request of the OP, a little word on another group of organic-walled microfossil with a extensive, coherent Paleozoic fossil record: the Chitinozoans.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This enigmatic group was found by &lt;strong&gt;Eisenack (1931)&lt;/strong&gt; and because of their resistance to acids &amp;amp; bases he thought they consisted of chitin, hence the name he gave them. However studies (&lt;strong&gt;Voss-Foucart &amp;amp; Jeuniaux 1972; Jacob et al. 2007&lt;/strong&gt;) showed that they do not consist of chitin or any kind of chitin-like bioproduct but of a network of kerogen with aromatic compounds. The diagenetic path that lead to this chemical composition is however unknown, meaning that we know neither what was their chemical composition when those organisms (NB: we don't know as well what their biological affinities are, though metazoan eggs seem to be a popular hypothesis, see e.g. &lt;strong&gt;Paris &amp;amp; Nõlvak 1999&lt;/strong&gt;) were alive nor how they preserved.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Additional sources:&lt;br&gt;&#xA;Eisenack, A., 1931. &lt;a href=&quot;http://dx.doi.org/10.1007/BF03043326&quot; rel=&quot;nofollow&quot;&gt;Neue Mikrofossilien des baltischen Silurs I&lt;/a&gt;.&#xA;Palaeontologische Zeitschrift, 13: 74–118.&lt;br&gt;&#xA;Jacob, J., &lt;em&gt;et al.&lt;/em&gt;, 2007. &lt;a href=&quot;http://dx.doi.org/10.1016/j.orggeochem.2007.06.005&quot; rel=&quot;nofollow&quot;&gt;New insights into the chemical composition of chitinozoans&lt;/a&gt;. Organic Geochemistry, 36(10): 1782–1788.&lt;br&gt;&#xA;Paris, F. &amp;amp; Nõlvak, J., 1999. &lt;a href=&quot;http://dx.doi.org/10.1016/S0016-6995(99)80045-X&quot; rel=&quot;nofollow&quot;&gt;Biological interpretation and paleobiodiversity of a cryptic fossil group: The “chitinozoan animal”&lt;/a&gt;. Geobios, 32(2): 315-324.&lt;br&gt;&#xA;Voss-Foucart, M.F. &amp;amp; Jeuniaux, C., 1972. Lack of chitin in a sample of Ordovician chitinozoa. Journal of Paleontology, 46: 769–770.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-08-20T07:19:23.900" LastActivityDate="2014-08-20T07:19:23.900" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="410" PostTypeId="2" ParentId="170" CreationDate="2014-04-22T07:29:32.560" Score="11" Body="&lt;p&gt;Normally I use the following softwares for a quick view of my NetCDF files:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;NASA Panoply (&lt;a href=&quot;http://www.giss.nasa.gov/tools/panoply/&quot; rel=&quot;nofollow&quot;&gt;Panoply netCDF, HDF and GRIB Data Viewer&lt;/a&gt;): java based, very good in opening HDF, NetCDF, GRIBs...&lt;/li&gt;&#xA;&lt;li&gt;CDO functions as shaded, contour, etc. (very basic but useful from command-line)&lt;/li&gt;&#xA;&lt;li&gt;MATLAB and R with their basic functions&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="9" LastEditorUserId="6093" LastEditDate="2016-10-02T09:25:53.267" LastActivityDate="2016-10-02T09:25:53.267" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="411" PostTypeId="5" CreationDate="2014-04-22T07:48:17.513" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-22T07:48:17.513" LastActivityDate="2014-04-22T07:48:17.513" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="412" PostTypeId="4" CreationDate="2014-04-22T07:48:17.513" Score="0" Body="Paleogeography is the study of past arrangements of the Earth surface." OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-04-22T13:03:58.430" LastActivityDate="2014-04-22T13:03:58.430" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="413" PostTypeId="5" CreationDate="2014-04-22T07:50:12.307" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-22T07:50:12.307" LastActivityDate="2014-04-22T07:50:12.307" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="414" PostTypeId="4" CreationDate="2014-04-22T07:50:12.307" Score="0" Body="Stratigraphy is the study of rock strata and their intrepretation in term of absolute or relative age." OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-04-22T13:03:54.090" LastActivityDate="2014-04-22T13:03:54.090" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="415" PostTypeId="1" AcceptedAnswerId="926" CreationDate="2014-04-22T08:04:43.140" Score="22" ViewCount="2802" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Peak_phosphorus&quot;&gt;The minable phosphorus reserves are limited&lt;/a&gt;. Where is the mined phosphoprus landing, what are the global phosphorus sinks?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would assume that most phosphorus is used for fertilizer and ultimately ends up in the water (via consumption by plants, than animals or humans and then wastewater or faeces). The most likely candidate in water would be phosphate ($PO_4^{-3}$). I would assume that phosphate is fixed in microorganisms and that those ultimatly form sediment and get mineralized. But this is a wild guess.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How does the phosphorus cycle actually work after phosphorus is used by humans and emitted into the environment? What are major processes, and in what forms is phosphorus mineralized?&lt;/p&gt;&#xA;" OwnerUserId="117" LastEditorDisplayName="user12525" LastEditDate="2019-04-18T11:22:26.950" LastActivityDate="2019-04-18T11:22:26.950" Title="Peak phosphorus - what are the sinks?" Tags="|geochemistry|mineralogy|biogeochemistry|geobiology|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="416" PostTypeId="1" AcceptedAnswerId="2609" CreationDate="2014-04-22T08:19:10.723" Score="12" ViewCount="147" Body="&lt;p&gt;Acantharians are planktonic protists (abundant in today oceans), sister-group to polycystine Radiolarians, that have the particularity of biomineralizing complex skeletons in strontium sulfate SrSO&lt;sub&gt;4&lt;/sub&gt; (i. e. celestine). &#xA;Those protists have no (as far as I know) fossil record for the good reason that celestine is soluble in seawater once the organism decayed. &#xA;However it has been speculated (e. g. &lt;strong&gt;Bernstein et al. 1992&lt;/strong&gt;) that acantharian-derived celestine could be at the origin of the formation of Sr-rich barite.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the status of this hypothesis? If this is still considered true, is there a way to differentiate unambiguously acantharian-derived barite from other kind of barite?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This would of course have interesting paleontological implications.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Source:&lt;br&gt;&#xA;Bernstein, R. E., Byrne, R. H., Betzer, P. R., Greco, A. M., 1992. &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/0016703792903042&quot; rel=&quot;nofollow&quot;&gt;Morphologies and transformations of celestite in seawater: The role of acantharians in strontium and barium geochemistry&lt;/a&gt;. Geochimica et Cosmochimica Acta, 56: 3273-3279.&#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="725" LastEditDate="2014-10-11T09:26:23.607" LastActivityDate="2014-10-11T09:26:23.607" Title="Barite and Acantharians" Tags="|paleontology|diagenesis|sedimentology|biomineralization|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="417" PostTypeId="2" ParentId="415" CreationDate="2014-04-22T08:34:31.897" Score="3" Body="&lt;p&gt;It is very likely that there will always be phosphorous for mining, because rising demand will increase prizes, and make more mining sites profitable (This is like the golden rule of mining and seen for example with oil sands suddenly being profitable).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From a crystalline-rock perspective (&lt;em&gt;this is just a partial answer&lt;/em&gt;) the phosphate minerals are a huge phosphorous sink. Prominent members of this group are Apatite, Monazite and Xenotime, which occur widely in granitic rocks. The problem with these minerals is that they can contain high percentages of radioactive elements and submicroscopic inclusions with even higher radioactivity. This has already contributed to the rise of radioactivity on fertilized fields and rivers that run from them (&lt;a href=&quot;http://link.springer.com/article/10.1007%2FBF00747688&quot; rel=&quot;nofollow&quot;&gt;http://link.springer.com/article/10.1007%2FBF00747688&lt;/a&gt;). This is relevant to your question because radioactivity and the isotopes that produce it, can be used as a tracer for phosphorous.&lt;/p&gt;&#xA;" OwnerUserId="23" LastActivityDate="2014-04-22T08:34:31.897" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="418" PostTypeId="1" AcceptedAnswerId="464" CreationDate="2014-04-22T09:04:12.183" Score="20" ViewCount="5079" Body="&lt;p&gt;Plate tectonics is a theory which describes Earth's lithosphere as being composed of distinct plates which are able to move atop of the underlying asthenosphere.  At plate boundaries, this movement can give rise to convergent boundaries where subduction may occur, divergent boundaries, where molten lava rises to fill the gaps between diverging plates, or sliding plates at transform boundaries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While I understand why we have come to adopt this theory, what I am less clear about is why  Earth's lithosphere is composed of such distinct plates in the first place, and is it possible for existing plates to split into two distinct plates?  Is there a theory on how the Earth's plates were initially formed?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="6467" LastEditorDisplayName="user12525" LastEditDate="2019-12-06T23:30:52.677" LastActivityDate="2019-12-06T23:30:52.677" Title="How did Earth's plate tectonics start?" Tags="|geology|geophysics|plate-tectonics|earth-history|" AnswerCount="3" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="420" PostTypeId="1" AcceptedAnswerId="439" CreationDate="2014-04-22T11:12:01.007" Score="13" ViewCount="5616" Body="&lt;p&gt;It is well known among regular beach goers that a sudden shoreline drawback is often a warning sign for an impending Tsunami.  My understanding of Tsunamis is they they form as a result of the seafloor abruptly changing, causing a local vertical displacement of water at the site of above the disruption, which initiates the wave. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/OFN7s.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How does this process ultimately result in the shoreline often receding prior to the Tsunami reaching the coast?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="725" LastEditDate="2014-11-30T06:34:04.943" LastActivityDate="2023-08-04T15:26:23.377" Title="Why does the shoreline sometimes recede prior to a Tsunami?" Tags="|ocean|tsunami|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="421" PostTypeId="1" AcceptedAnswerId="443" CreationDate="2014-04-22T11:17:09.303" Score="15" ViewCount="2756" Body="&lt;p&gt;We all know that as waves approach the shallow shores, the waves begin to form a characteristic shape.  The upper portion of these breaking waves appears to curl forward and downwards over the bottom segment of the wave, before breaking into &quot;white wash&quot;. The image below illustrates what this characteristic shape looks like:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/N130G.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So why do waves form this characteristic breaking shape as they approach the shallow shores?&lt;/p&gt;&#xA;" OwnerUserId="51" LastActivityDate="2023-08-04T15:34:00.067" Title="What causes waves to form the characteristic &quot;breaking&quot; shape as they approach the shoreline?" Tags="|ocean|waves|" AnswerCount="3" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="422" PostTypeId="1" AcceptedAnswerId="423" CreationDate="2014-04-22T11:57:26.257" Score="22" ViewCount="76743" Body="&lt;p&gt;In the theory of tectonic plates, at a convergent boundary between a continental plate and an oceanic plate, the denser plate usually subducts underneath the less dense plate.  It is well known that oceanic plates subduct under continental plates, and therefore oceanic plates are more dense than continental plates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is why are the oceanic plates always denser than the continental plates.  I'm aware that the difference in density can be attributed to the plates differing compositions, but what I'm interested in is why these plates have different composition in the first place giving rise to their relative difference in densities.&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorDisplayName="user12525" LastEditDate="2019-04-21T10:37:08.400" LastActivityDate="2019-04-21T10:37:08.400" Title="Why are oceanic plates denser than continental plates?" Tags="|geology|geophysics|plate-tectonics|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="423" PostTypeId="2" ParentId="422" CreationDate="2014-04-22T13:04:05.360" Score="24" Body="&lt;p&gt;Ocean lithosphere (geophysical definition of crust + upper mantle that acts as a 'plate') is primarily of basaltic composition - the upper levels are basalt and the lower levels are gabbro. The top levels have been proven with boreholes, whilst the lower levels have been inferred from transform fault sampling and comparisons with ophiolites. This sequence is produced by partial melting of mantle peridotite at a fairly controlled rate. So much so that basalts formed in this way even have a specific composition &quot;MORB&quot; (Mid Ocean Ridge Basalt).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In contrast, continent lithosphere is more complex and tends to be of a 'granitic' composition. This includes granites but can also include a lot of metamorphic rocks (eg. gneiss) and sediments. Sediments are lower density anyway (high pore space), but so are quartz-rich rocks such as granites. The various processes that build continents tend to favour silica rich compositions, resulting in this bulk &quot;granitic&quot; composition. For example, limited partial melting will initially produce high silica, high alkali melts. Erosion will tend to break down most common minerals before quartz - leaving quartz-rich sediments (hence sandstone is primarily quartz). Metamorphism of pelites (rocks rich in Al and Si) will tend from the initial mudstones &amp;amp; basalts through to gneisses &amp;amp; migmatites (which have a lot of quartz and feldspar). Migmatites are partially melted - and the melted bits are essentially granite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basalt is denser than granite. On gravity surveys, basalts and gabbros will appear as positive anomalies, whilst granites and sedimentary basins will appear as negative anomalies.&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorUserId="44" LastEditDate="2014-04-22T19:25:10.010" LastActivityDate="2014-04-22T19:25:10.010" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="424" PostTypeId="1" AcceptedAnswerId="427" CreationDate="2014-04-22T15:16:12.193" Score="13" ViewCount="624" Body="&lt;p&gt;There have been some claims made (&lt;a href=&quot;http://www.csmonitor.com/Science/2014/0106/How-frigid-polar-vortex-could-be-result-of-global-warming-video&quot;&gt;example&lt;/a&gt;) that global warming had something to do with why the 2013-2014 winter was so cold in the Midwest area of America.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this is true then how did global warming make the winter so cold? Shouldn't it make the temperature rise in all parts of the world, during all seasons?&lt;/p&gt;&#xA;" OwnerUserId="181" LastEditorUserId="56" LastEditDate="2014-09-10T07:44:12.460" LastActivityDate="2016-12-24T11:21:06.120" Title="Did global warming cause the extreme cold 2013-14 winter in North America?" Tags="|climate|temperature|global-warming|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="427" PostTypeId="2" ParentId="424" CreationDate="2014-04-22T16:27:34.510" Score="20" Body="&lt;p&gt;I bet you live on the eastern half of North America, which had a cold winter of 2013-2014, Europe and Alaska had a very warm winter, and China had its second warmest January.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Jennifer Francis of Rutgers has been advocating the Arctic or Polar Amplification theory (&lt;a href=&quot;https://en.wikipedia.org/wiki/Polar_amplification&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;). In which she hypothesises that warming of the Arctic has been greater than lower latitudes, and this lowers the temperature contrast between the poles and the equator. This in turn weakens the jet stream which becomes slow and meandering. This weakened and meandering jet stream then is less able to hold back cold polar air, the so called &quot;polar vortex&quot; which can then bring outbreaks of cold air from the poles to the mid latitudes.(&lt;a href=&quot;http://www.bbc.co.uk/news/science-environment-26023166&quot; rel=&quot;nofollow noreferrer&quot;&gt;BBC Article outlining the theory&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the theory is not without some problems... &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;One problem is that the changes in atmospheric thickness and wind&#xA;  speed observed have become apparent only since the mid-1990s, which&#xA;  gives fewer than 20 years of data to work with. Another difficulty&#xA;  concerns the blocking patterns. Dr Francis’s theory suggests there&#xA;  will be more of them in future, as the world warms. But climate models&#xA;  unanimously disagree, saying that global warming will produce fewer of&#xA;  them...(&lt;a href=&quot;http://www.economist.com/news/science-and-technology/21596920-polar-warming-blame-americas-and-britains-bad-winter-weather-jet-set&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Economist&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tim Woollings, an atmospheric dynamics researcher at Oxford University pointed out in an email exchange that over the Atlantic the jet stream was stuck, but was not meandering or slowed, however he did concede that the jet stream over the Pacific did match the hypothesis.(&lt;a href=&quot;http://e360.yale.edu/feature/is_weird_winter_weather_related_to_climate_change/2742/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Yale Environment 360&lt;/a&gt;) The jet stream over the Atlantic reached sustained speeds over 230 miles per hour (370 km/h) during the winter,(&lt;a href=&quot;http://blogs.channel4.com/liam-dutton-on-weather/weeks-stormy/5573&quot; rel=&quot;nofollow noreferrer&quot;&gt;Liam Dutton&lt;/a&gt;) reaching  275 miles per hour (443 km/h) on 22 December 2013. 30% stronger than the normal jet stream.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So yes, there is a theory which describes how warming can bring locally colder winters, but also, the science isn't exactly settled yet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Addendum: here's a link to a good blog post on the matter &lt;a href=&quot;http://robertscribbler.wordpress.com/2014/02/28/7656/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Polar Amplification, Vortex Disruption to Set off Extreme Weather Events For US, UK Yet Again&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An overview of the debate as of 2016:&lt;a href=&quot;https://www.washingtonpost.com/news/energy-environment/wp/2016/12/23/the-arctic-is-behaving-so-bizarrely-and-these-scientists-think-they-know-why/?postshare=5831482554415631&amp;amp;tid=ss_tw-bottom&amp;amp;utm_term=.7a49de2c1794&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wapo 2016&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="140" LastEditorUserId="140" LastEditDate="2016-12-24T11:21:06.120" LastActivityDate="2016-12-24T11:21:06.120" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="428" PostTypeId="1" AcceptedAnswerId="431" CreationDate="2014-04-22T16:36:55.093" Score="26" ViewCount="13133" Body="&lt;p&gt;Will all the drilling and digging to use the Earth's natural heat as geothermal energy affect the Earth's core, causing it to cool down?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If so, would it result in an ice age?  If not, how does the Earth's core retain its heat?&lt;/p&gt;&#xA;" OwnerUserId="181" LastEditorUserId="6129" LastEditorDisplayName="user889" LastEditDate="2020-05-06T13:28:22.493" LastActivityDate="2020-05-06T13:28:22.493" Title="Could the Earth's core lose its heat?" Tags="|geophysics|geodynamics|core|geothermal-heat|human-influence|" AnswerCount="7" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="429" PostTypeId="2" ParentId="428" CreationDate="2014-04-22T16:46:28.723" Score="20" Body="&lt;p&gt;This question is relevant, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/94/why-is-the-inside-of-the-earth-so-hot/97#97&quot;&gt;Why is the inside of the Earth so hot?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The short answer is the core is losing heat no matter what we do. You see, heat is transported from the core to the surface, but its important to think of heat in terms of energy. Since there is a finite amount of energy within the earth, we are actually transferring energy from the inside to the out. It works similar to a internal combustion engine found inside your car. You are converting a potential difference (High and Low temperature) into mechanical energy. In Earth's case, this mechanical energy is represented as as convection cells, which drive plate tectonics. Eventually, an engine runs out of gas, or in Earth's case, energy, and will begin to cool off.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the core cools down, I don't think an ice age would be the right think to say. Mars would be a good example of what might happen to Earth when it loses most of its heat. There will no longer be tectonic events like volcanism, Earth will be a cold ball of mass. There will be a lot of ice, but eventually cosmic radiation and solar winds will destroy the atmosphere without the protection of the Earth's magnetic field leaving a barren planet with a largely homogenous surface. So sure, it will cause an ice age, but the ultimate destiny of the planet is barren, with a solid non-convecting mantle and core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to add this this is largely speculation, that we really don't know what will happen. I just assume that Earth will share a similar fate to Mars. Mars once had a magnetic field protecting its atmosphere, but as the planet cooled off the field disappeared. Mars's historic magnetic field is an area of contentious research.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As gerrit pointed out, Venus has an atmosphere without a magnetic field, so this is clearly postulation. Perhaps an expert will shed light on this question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/432/how-long-would-earths-atmosphere-last-without-a-global-magnetic-field&quot;&gt;(How long) would Earth&amp;#39;s atmosphere last without a global magnetic field?&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-04-22T18:22:00.663" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="430" PostTypeId="2" ParentId="345" CreationDate="2014-04-22T17:12:21.103" Score="4" Body="&lt;p&gt;The color of a mineral can be caused by a variety of mechanisms. This is also true of amethyst, which is a variety of quartz ($\ce{SiO2}$), and can be found in many colors. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The major factors responsible for the &lt;a href=&quot;http://www.enmu.edu/services/museums/miles-mineral/colors.shtml&quot; rel=&quot;nofollow&quot;&gt;production of color&lt;/a&gt; in minerals fall into five categories:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The presence of an element essential to the mineral composition&lt;/li&gt;&#xA;&lt;li&gt;The presence of a minor chemical impurity&lt;/li&gt;&#xA;&lt;li&gt;Physical defects in the crystal structure&lt;/li&gt;&#xA;&lt;li&gt;The mechanical mixture of very fine impurities&lt;/li&gt;&#xA;&lt;li&gt;The presence of finely-spaced structures in the mineral&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;See these pages for more information about the &lt;a href=&quot;http://minerals.gps.caltech.edu/COLOR_Causes/index.html&quot; rel=&quot;nofollow&quot;&gt;causes of color in minerals&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you search for &quot;Color Centers in Quartz&quot; you will find a large literature on this subject. Some color centers in quartz can be created or destroyed by irradiating crystals with light or X-rays. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The quantitative measurement and study of mineral color is called &lt;a href=&quot;http://minerals.gps.caltech.edu/&quot; rel=&quot;nofollow&quot;&gt;Mineral Spectroscopy&lt;/a&gt;.   &lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorDisplayName="user889" LastEditDate="2014-12-19T10:02:13.460" LastActivityDate="2014-12-19T10:02:13.460" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="431" PostTypeId="2" ParentId="428" CreationDate="2014-04-22T17:40:48.040" Score="32" Body="&lt;p&gt;Part 1, see &lt;a href=&quot;https://earthscience.stackexchange.com/a/429/6&quot;&gt;Neos answer&lt;/a&gt;.  Earth will lose its heat no matter what we do, and our extraction of geothermal energy is insignificant (&lt;a href=&quot;https://en.wikipedia.org/wiki/Geothermal_energy#cite_ref-5&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia quotes a BP figure of 11.4 GW electrical, 28 GW heating&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer part 2 of your question: if the Earth's core loses its heat, this will not have a major direct impact on climate.  &lt;strong&gt;Internal heat generation is estimated&lt;/strong&gt; by &lt;a href=&quot;http://www.solid-earth.net/1/5/2010/se-1-5-2010.html&quot; rel=&quot;noreferrer&quot;&gt;Davies and Davies (2010)&lt;/a&gt; &lt;strong&gt;to be roughly&lt;/strong&gt; 47 TW.  With a surface area of 5.1 &amp;times; 10&lt;sup&gt;14&lt;/sup&gt; m&lt;sup&gt;2&lt;/sup&gt;, this translates to roughly &lt;strong&gt;0.1 W/m&lt;sup&gt;2&lt;/sup&gt;&lt;/strong&gt;.  This can be compared to the other flows in the climate system, illustrated by &lt;a href=&quot;http://link.springer.com/article/10.1007%2Fs10712-011-9150-2&quot; rel=&quot;noreferrer&quot;&gt;Trenberth and Fasullo, 2012&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Oydvq.png&quot; alt=&quot;Global energy flows&quot;&gt;&#xA;&lt;br /&gt;&amp;mdash;Trenberth, Kevin E., and John T. Fasullo. &quot;Tracking Earth’s energy: From El Niño to global warming.&quot; Surveys in geophysics 33, no. 3-4 (2012): 413-426.  &lt;a href=&quot;http://link.springer.com/article/10.1007%2Fs10712-011-9150-2#&quot; rel=&quot;noreferrer&quot;&gt;Weblink&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, from a climate perspective, internal heat generation is not important.  See also &lt;a href=&quot;http://www.skepticalscience.com/heatflow.html&quot; rel=&quot;noreferrer&quot;&gt;this post on skepticalscience&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;However&lt;/em&gt;, we might lose our atmosphere, which &lt;em&gt;would&lt;/em&gt; have inconvenient consequences.  An ice age would be the least of our worries.  A subsequent question would be: &lt;em&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/432/6&quot;&gt;(How long) would Earth&amp;#39;s atmosphere last without a global magnetic field?&lt;/a&gt;&lt;/em&gt;  That is a different question and I'm not sure if we really know the answer.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-04-23T23:23:55.793" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="432" PostTypeId="1" AcceptedAnswerId="662" CreationDate="2014-04-22T18:09:51.510" Score="44" ViewCount="6556" Body="&lt;p&gt;The Earth's magnetic field provides an important protection against the solar wind (for example, &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_magnetic_field#Importance&quot;&gt;see Wikipedia on Earth's magnetic field&lt;/a&gt; and references therein).  Mars may have lost its atmosphere because it did not retain such a magnetic field, although &lt;a href=&quot;https://en.wikipedia.org/wiki/Venus#Magnetic_field_and_core&quot;&gt;Venus does not have an intrinsic magnetic field either&lt;/a&gt;.  This raises the question: what will happen to Earth's atmosphere if the global magnetic field would disappear?  Would the solar wind blow it all away?  If so, how long would it take until only a small part (&amp;lt;10 kPa sea level pressure) is left?&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="56" LastEditDate="2014-09-18T06:03:23.240" LastActivityDate="2023-01-09T12:23:57.983" Title="(How long) would Earth's atmosphere last without a global magnetic field?" Tags="|atmosphere|hypothetical|solar-terrestrial-physics|magnetosphere|" AnswerCount="2" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="436" PostTypeId="1" CreationDate="2014-04-22T21:33:44.080" Score="21" ViewCount="1647" Body="&lt;p&gt;During the termination of the latest ice age the warming climate leading from glacial to interglacial conditions was abruptly reverted by a distinct but short (about 1300 years in duration) cold event, referred to as the Younger Dryas. This event resulted in substantial moraine zones around the southern edges of the Fennoscandian ice sheet, indicating a halt in retreat. There are also evidence of strong permafrost conditions in the periglacial area. What caused this cold event?&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="725" LastEditDate="2014-11-30T06:38:14.643" LastActivityDate="2019-01-31T17:12:46.427" Title="What caused the Younger Dryas cold event?" Tags="|climate-change|paleoclimatology|ice-age|younger-dryas|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="437" PostTypeId="2" ParentId="432" CreationDate="2014-04-22T23:06:45.007" Score="15" Body="&lt;p&gt;Since atmospheric retention is largely dependent on escape velocity and temperature, removal of the Earth's magnetic field should not have a greatly noticeable effect, as current research shows that Earth's magnetic field changes the location of atmosphere loss due to the solar wind rather than eliminating it.  Earth's temperature is not likely to change much without a magnetic field (with the current solar luminosity), so that too can be discounted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is far more likely that Earth's atmosphere will diminish as a result of increasing temperature as the sun expands due to an increase in helium fusion as it runs out of hydrogen, a phenomenon that would not be dependent on having or not having a magnetic field.  That would be in roughly 5 to 7 billion years according to the &lt;a href=&quot;http://en.wikipedia.org/wiki/Future_of_the_Earth&quot;&gt;Atmospheric Escape&lt;/a&gt; and the &lt;a href=&quot;http://en.wikipedia.org/wiki/Formation_and_evolution_of_the_Solar_System#Timeline_of_Solar_System_evolution&quot;&gt;Formation and evolution of the Solar System &lt;/a&gt; Wikipedia articles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we discount solar expansion and make the convenient but incorrect assumption that solar wind and temperature will remain constant over time, then it is possible that Earth's atmosphere could be stripped in a timeframe on the order of many trillions of years.  See the &lt;a href=&quot;http://en.wikipedia.org/wiki/Atmospheric_escape&quot;&gt;Atmospheric Escape&lt;/a&gt; Wikipedia article, and this &lt;a href=&quot;http://www.space.com/11187-earth-magnetic-field-solar-wind.html&quot;&gt;How Vital Is a Planet's Magnetic Field&lt;/a&gt; Space.com article.&lt;/p&gt;&#xA;" OwnerUserId="133" LastEditorUserId="133" LastEditDate="2014-04-23T23:55:22.067" LastActivityDate="2014-04-23T23:55:22.067" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="438" PostTypeId="2" ParentId="428" CreationDate="2014-04-23T00:01:41.250" Score="18" Body="&lt;p&gt;Put a frying pan on a stove burner and make the pan hot. Measure its temperature every minute over half an hour or so to get an idea of how rapidly it naturally cools.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then start the experiment over again. This time, take a needle and touch and hold its tip to the frying pan so that it acts as a heat sink. The relative sizes of frying pan and needle will approximate &quot;Earth and current methods of geothermal energy transfer&quot;. Measure the cooling over the next half hour.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you run the two experiments a few times and compare results, you should find that it's practically impossible to detect any difference. The results can be extrapolated to estimate effects on the Earth, and a plausible conclusion is that it won't make a meaningful difference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The simple reason is that our current geothermal efforts (as well as any currently projected future efforts) are so vanishingly small when compared to the size of the Earth that it has less effect than we can measure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, that doesn't mean that some radical future change in technology won't change things. But no one can answer on those terms except to assert that we could make a significant difference if we could advance technology far enough.&lt;/p&gt;&#xA;" OwnerUserId="198" LastActivityDate="2014-04-23T00:01:41.250" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="439" PostTypeId="2" ParentId="420" CreationDate="2014-04-23T00:05:27.737" Score="12" Body="&lt;p&gt;It has nothing to do with the geological cause of the tsunami. Instead, it's a result of the way waves propagate. You can see the same effect on ordinary wind-generated ocean waves — the waterline draws back before each wave peak arrives and washes up the beach. Tsunamis are much bigger waves, in terms of both amplitude and wavelength, so the effect is more dramatic. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The particles in some surface waves, including &lt;a href=&quot;http://en.wikipedia.org/wiki/Wind_wave&quot;&gt;wind waves&lt;/a&gt; and &lt;a href=&quot;http://en.wikipedia.org/wiki/Rayleigh_wave&quot;&gt;Rayleigh waves&lt;/a&gt; (a component of what is often called ground roll), have in a circular or elliptical motion — in the case of a wind wave the motion is clockwise if the wave is traveling from left to right (see &lt;a href=&quot;http://www.acs.psu.edu/drussell/demos/waves/wavemotion.html&quot;&gt;this animated comparison&lt;/a&gt; for Rayleigh waves). The 'backwards' motion in the trough results in the &lt;a href=&quot;http://en.wikipedia.org/wiki/Tsunami#Drawback&quot;&gt;drawback&lt;/a&gt; you are asking about.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2014-04-23T00:05:27.737" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="440" PostTypeId="2" ParentId="295" CreationDate="2014-04-23T00:32:13.893" Score="12" Body="&lt;p&gt;There are lots of articles that assess global models both locally and globally. They usually focus on a few parameters that are easily comparable with observations (e.g., temperature, wind, surface pressure). A couple of examples of the many available: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;for ECMWF:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Roberto Buizza, 1997: &lt;a href=&quot;http://journals.ametsoc.org/doi/full/10.1175/1520-0493%281997%29125%3C0099:PFSOEP%3E2.0.CO%3B2&quot; rel=&quot;nofollow&quot;&gt;Potential Forecast Skill of Ensemble Prediction and Spread and Skill Distributions of the ECMWF Ensemble Prediction System.&lt;/a&gt; &lt;em&gt;Mon. Wea. Rev.,&lt;/em&gt; &lt;strong&gt;125&lt;/strong&gt;, 99–119, doi: 10.1175/1520-0493(1997)125&amp;lt;0099:PFSOEP&gt;2.0.CO;2.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;for both only looking at precipitation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thomas M. Hamill, Renate Hagedorn, and Jeffrey S. Whitaker, 2008: &lt;a href=&quot;http://journals.ametsoc.org/doi/full/10.1175/2007MWR2411.1&quot; rel=&quot;nofollow&quot;&gt;Probabilistic Forecast Calibration Using ECMWF and GFS Ensemble Reforecasts. Part II: Precipitation.&lt;/a&gt; &lt;em&gt;Mon. Wea. Rev.,&lt;/em&gt; &lt;strong&gt;136&lt;/strong&gt;, 2620–2632, doi: 10.1175/2007MWR2411.1.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;For the climate model world, check out: &lt;a href=&quot;http://www-pcmdi.llnl.gov&quot; rel=&quot;nofollow&quot;&gt;http://www-pcmdi.llnl.gov&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="111" LastEditorUserId="20" LastEditDate="2016-09-11T03:14:34.587" LastActivityDate="2016-09-11T03:14:34.587" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="441" PostTypeId="1" CreationDate="2014-04-23T00:57:42.653" Score="9" ViewCount="800" Body="&lt;p&gt;Generating finite element/volume grids is tricky for ocean models, especially when you are dealing with complex coastlines. What are the more common tools to create the grids and to check the quality (e.g., minimum angles, wave propagation constraints) of it?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="543" LastEditDate="2023-10-17T04:57:52.747" LastActivityDate="2023-10-17T04:57:52.747" Title="What tools are available to build unstructured grids for ocean models?" Tags="|oceanography|models|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="442" PostTypeId="1" AcceptedAnswerId="2380" CreationDate="2014-04-23T01:05:42.583" Score="10" ViewCount="114" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Plant_functional_type&quot;&gt;Plant Functional Types (PFTs)&lt;/a&gt; are a discretisation of global vegetation types. They are used in land surface models to parametrise many values, including albedo, various photosynthesis parameters, and water use. These affect the resultant estimates of Net Ecosystem Exchange of carbon (NEE), and heat and radiation budgets, and what happens to soil moisture. However, Alton (2011) has showed that for some of these parametrised variables, there is no significant difference between many commonly used PFTs. This means that PFTs may, in some cases, be a less than optimal method of deciding how each land surface model grid cell should operate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any alternative parametrisations of the global land surface that could provide more, or better information to land surface models? Perhaps based on soil types, or even statistical parametrisations (like something PCA based)? If so, are any in use in any current land surface models?&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Alton, P.B., 2011. How useful are plant functional types in global simulations of the carbon, water, and energy cycles? &lt;em&gt;Journal of Geophysical Research&lt;/em&gt;, 116(G1). Available at: &lt;a href=&quot;http://doi.wiley.com/10.1029/2010JG001430&quot;&gt;http://doi.wiley.com/10.1029/2010JG001430&lt;/a&gt; [Accessed August 26, 2013].&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="56" LastActivityDate="2014-08-19T14:48:59.133" Title="Alternatives to Plant Functional Types as parametrisations in land surface models?" Tags="|land-surface|climate-models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="443" PostTypeId="2" ParentId="421" CreationDate="2014-04-23T01:15:00.723" Score="18" Body="&lt;p&gt;The physical process you describe is known as &lt;a href=&quot;http://en.wikipedia.org/wiki/Wave_shoaling&quot;&gt;wave shoaling&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the basic level, waves propagating into shallow water become shorter and higher, and consequently, steeper. In shallow water, the water particles near the crest move &lt;strong&gt;forward&lt;/strong&gt; faster than those below them. Similarly, the particles near the trough move &lt;strong&gt;backward&lt;/strong&gt; faster than those above them. This causes strong shearing of the near-surface body of water, eventually forming a plunging breaker, or a surf wave. For small-slope (linear) and inviscid (no friction) waves, the above is a consequence of the bottom boundary condition for the water velocity to be zero at the sea floor. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two fundamental and related properties of water waves that contribute to shoaling. One is the wave frequency $\omega$ remaining constant as the depth $d$ decreases. Think of this as the conservation of wave crests at any fixed point. However, the wavenumber $k$ (wavelength $\lambda$) must increase (decrease) with decreasing depth, as per the &lt;a href=&quot;http://en.wikipedia.org/wiki/Dispersion_%28water_waves%29&quot;&gt;dispersion relationship&lt;/a&gt; of water waves (neglecting the effects of viscosity):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\omega^{2} = gk\tanh{(kd)}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $g$ is gravitational acceleration. In shallow water, the dispersion relationship reduces to:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\omega = \sqrt{gd}k $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and phase speed $C_p$ and group velocity $C_g$ are both proportional to the square root of the water depth:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ C_p = \dfrac{\omega}{k} = \sqrt{gd} $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ C_g = \dfrac{\partial\omega}{\partial k} = \sqrt{gd} $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Individual wave crests propagate with phase speed $C_p$. Wave groups and wave energy propagate with group velocity $C_g$. Thus, waves entering shallow water become &lt;strong&gt;shorter&lt;/strong&gt; and &lt;strong&gt;slower&lt;/strong&gt;. The second important property leading to shoaling is the conservation of wave energy flux, which is proportional to the group velocity and wave energy: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\dfrac{\partial(C_{g}E)}{\partial x}=0$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because the group velocity decreases, the wave energy (read: height) must increase (locally). This causes the waves to grow in height as they enter shallow water. As pointed out by @IsopycnalOscillation in a comment above, the separation of water particles from the wave crests happen because the individual orbital velocities at the top of the crest exceed by far the phase speed of the wave.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although bottom friction is significant and non-negligible in shallow water, it does not cause shoaling. Mathematically, wave shoaling can occur for completely inviscid and small-slope (linear) waves that propagate into water of decreasing depth.&lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2014-04-24T15:35:00.220" LastActivityDate="2014-04-24T15:35:00.220" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="444" PostTypeId="2" ParentId="170" CreationDate="2014-04-23T03:52:58.770" Score="13" Body="&lt;p&gt;I second &lt;a href=&quot;http://meteora.ucsd.edu/~pierce/ncview_home_page.html&quot;&gt;ncview&lt;/a&gt; for taking a quick look at NetCDF files.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would also recommend trying Unidata's &lt;a href=&quot;http://www.unidata.ucar.edu/software/idv/&quot;&gt;Integrated Data Viewer (IDV)&lt;/a&gt;. It is great for overlaying geophysical fields in 3-D from different sources. Besides NetCDF, it supports many other formats. It also comes with a pre-loaded listing of various observational and model data repositories through THREDDS and OpenDAP. IDV also lets you to define functions and operations between fields on different grids or projections. Note that IDV is not good for serious analysis in my opinion, but is more suitable for exploring datasets visually.&lt;/p&gt;&#xA;" OwnerUserId="192" LastActivityDate="2014-04-23T03:52:58.770" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="446" PostTypeId="1" AcceptedAnswerId="457" CreationDate="2014-04-23T05:25:03.900" Score="47" ViewCount="21047" Body="&lt;p&gt;Snowflakes are known to form into pretty hexagonal structures.  The image below shows a variety of such structures that are possible (although by all means not an exhaustive list): &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/EHmok.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the mechanism for snowflakes forming into these delightful symmetric hexagonal structures?  Also what is the mechanism for the differing shapes in each of the different snow flakes?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="64" LastEditDate="2014-04-24T00:48:59.760" LastActivityDate="2020-04-15T06:55:37.287" Title="Why do snowflakes form into hexagonal structures?" Tags="|meteorology|snow|crystallography|" AnswerCount="5" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="447" PostTypeId="2" ParentId="170" CreationDate="2014-04-23T07:04:39.570" Score="12" Body="&lt;p&gt;Just to add my point of view; &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Using ncks you can do many things, i.e. differentiate, get&#xA;ratio, extract some vars, slice on the dimension etc..&lt;/li&gt;&#xA;&lt;li&gt;If you want to make some binary operations on netcdf files consider ncbo. For huge files I prefer to cut down what I want at the first place, it does opendap remote as well. &lt;/li&gt;&#xA;&lt;li&gt;Hate matlab so I moved to NCL &lt;a href=&quot;http://www.ncl.ucar.edu/&quot; rel=&quot;nofollow&quot;&gt;(NCAR)&lt;/a&gt;&#xA;which is straight forward and has many scripts already prepared for most &lt;a href=&quot;http://www.ncl.ucar.edu/Applications/list_models.shtml&quot; rel=&quot;nofollow&quot;&gt;common models&lt;/a&gt; . &#xA;No need to tell it is producing publication quality figures ;)&lt;/li&gt;&#xA;&lt;li&gt;There is portion of the lib for python (pyNGL), the same syntax so once when familiar with ncl easy to use it in python as well, support for other formats like grib, hdf, ... &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="207" LastEditorUserId="6093" LastEditDate="2016-10-01T15:12:15.023" LastActivityDate="2016-10-01T15:12:15.023" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="448" PostTypeId="1" AcceptedAnswerId="7945" CreationDate="2014-04-23T07:09:02.740" Score="14" ViewCount="199" Body="&lt;p&gt;Inspired by Chris McKay's &lt;a href=&quot;http://www.astro.sunysb.edu/astro/seminars/archive/JS09/jcl27Feb09-1.pdf&quot;&gt;Possibilities for methanogenic life in liquid methane on the surface of Titan&lt;/a&gt;. In the paper, the PI's found that the consumed acetylene, ethane, and other organic solids would produce enough energy for bacteria to live. They hypothesize that because the Cassini-Huygens probe detects a depletion of acetylene, ethane and hydrogen on Titan's surface, that living bacteria &lt;em&gt;could&lt;/em&gt; be a possible causation for this anomaly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously, there is some fantasy in this paper, but it is interesting none the less. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is, How could a scientist falsify this hypothesis? What biomarkers would be useful to look for? What kinds of sensors would track these biomarkers?&lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="32" LastEditDate="2014-04-23T15:17:04.303" LastActivityDate="2016-05-03T21:22:09.013" Title="What kinds of remote sensing required to observe methanogenic life on Titan?" Tags="|measurements|remote-sensing|astrobiology|planetary-science|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="449" PostTypeId="2" ParentId="441" CreationDate="2014-04-23T07:14:32.690" Score="4" Body="&lt;p&gt;The simplest is triangle &lt;a href=&quot;http://www.cs.cmu.edu/~quake/triangle.html&quot; rel=&quot;nofollow&quot;&gt;http://www.cs.cmu.edu/~quake/triangle.html&lt;/a&gt; which is providing lib form many other more advanced packages. You can create poly file and create &quot;holes/islands&quot; in grid etc. Easy to make simple grids.&#xA;Another more advanced / gui is xmgredit where you can create/modify grids.&#xA;Blue kenue  etc.. &#xA;use the force luke, do a google and it will popup many other packages,&#xA;I just wrote a few which are free and for 2D ocean applications.&lt;/p&gt;&#xA;" OwnerUserId="207" LastEditorUserId="124" LastEditDate="2014-04-24T17:58:04.803" LastActivityDate="2014-04-24T17:58:04.803" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="450" PostTypeId="2" ParentId="446" CreationDate="2014-04-23T08:45:38.467" Score="27" Body="&lt;p&gt;H&lt;sub&gt;2&lt;/sub&gt;O ice on Earth crystallizes with a structure called &quot;Ice-Ih&quot; which is hexagonal. The structure is dependent on the dipole properties of H&lt;sub&gt;2&lt;/sub&gt;O-molecules. Similar to what water does with ions to bring them into solution, the crystal structure is dependent on the energetically favourable alignment of the dipoles. In Ice-Ih the most favourable alignment is a (more or less) plane hexagonal ring with the negative dipole (the oxygen) facing (more or less) inwards. Neighbouring rings in the same plane and rings in the above and below plane are held together by hydrogen bonds (the positive dipole the both hydrogens). (See:&#xA;&lt;a href=&quot;http://www1.lsbu.ac.uk/water/ice1h.html&quot; rel=&quot;nofollow&quot;&gt;Hexagonal Ice (ice Ih)&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Snow flakes are all different, because crystal growth is very dynamic. While one crystal face grows another one can be susceptible to dissolution. While the snow flake is blown around through the air, temperature and humidity are always changing. This has the additional effect that sometimes crystal nucleation and sometimes crystal growth (which are energetically favourable at different temperatures) are active. While the snow flake descends the same dynamic continues. The crystal competes with liquid water and humidty for H&lt;sub&gt;2&lt;/sub&gt;O-molecules. Even the crystal faces compete with each other leading to for example dissolution of molecules on the inside and crystallization on the outside. Because no snowflake experiences the same conditions in the same history, every one looks a little different (not surprising because actually there are also not two &lt;a href=&quot;http://en.wikipedia.org/wiki/Zircon&quot; rel=&quot;nofollow&quot;&gt;Zircon&lt;/a&gt; crystals that look alike, or two flowers that look alike, etc...).&lt;/p&gt;&#xA;" OwnerUserId="23" LastEditorUserId="6093" LastEditDate="2016-10-11T15:12:04.810" LastActivityDate="2016-10-11T15:12:04.810" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="451" PostTypeId="2" ParentId="69" CreationDate="2014-04-23T09:09:40.120" Score="7" Body="&lt;p&gt;Good question.  It would seem without much thought, that air in a high pressure zone should move towards the air in low pressure zone, resulting in a disappearance of the pressure gradient.  The reason this does not occur is because there other forces (or pseudo-forces) at work, acting in addition to the force resulting from the pressure gradient.  I will outline such forces below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;1.  Pressure Gradient:&lt;/strong&gt; &lt;br&gt;&#xA;This is the force resulting from the pressure difference between a high and low pressure zone.  We term this a pressure gradient, because the pressure change is continuous rather than a discrete change between a high and low pressure zone.  We can model the acceleration in a particular direction resulting from a pressure gradient using the equation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\alpha=\frac{-1}{\rho}\frac{dP}{dz}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\alpha$ is the acceleration at a given point, $\rho$ is the density of air at that point, and $dP/dz$ represents a small change in pressure over a small change in horizontal distance.  More generally, we can model the acceleration vector in 3-dimensions using the equation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\vec{\alpha}=\frac{-1}{\rho}\vec{\nabla}P$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now if the pressure gradient was the only force at work, it is obvious from above that the acceleration would be directed from high pressure areas to low pressure areas, ultimately resulting in a dissipation of such gradients.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The next pseudo-force to consider however is the Coriolis effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;2. Coriolis Effect:&lt;/strong&gt;&lt;br&gt;&#xA;The Coriolis effect influences winds away from the equator that move horizontally.  Such winds in the northern hemisphere are deflected to the right, whereas winds in the southern hemisphere are directed to the left.  This is a result of the Earth's rotation.  (More information on this effect can be in the question and answer &lt;a href=&quot;https://physics.stackexchange.com/questions/43124/is-there-an-intuitive-explanation-for-the-southward-force-caused-by-the-coriolis/52509#52509&quot;&gt;here&lt;/a&gt;).  The acceleration resulting from the Coriolis psuedo-force is given by the following equation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\boldsymbol{a}_C=-2\Omega\times\boldsymbol{v}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\Omega$ represents the angular velocity of the Earth and $\boldsymbol{v}$ represents the velocity of the wind.  The cross product here is of significance and indicates that the deflection of the Coriolis effect will be at right angles to the direction of the wind's velocity.  More details of deriving the specific result for the Earth at different angles of latitude can be found &lt;a href=&quot;http://en.wikipedia.org/wiki/Coriolis_effect#Applied_to_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So how does this Coriolis effect stop wind from moving from high pressure to low pressure?  Well imagine that wind begins to move North (in the northern hemisphere) from a high pressure region to a low pressure region.  Due to the Coriolis effect, this wind will be deflected to the right, and will continue to be deflected in such a manner until the pseduo-force resulting from the Coriolis effect exactly balances the force due to the pressure gradient (ignoring friction for the time being).  &lt;strong&gt;At this time, we say the wind is said to be in geostrophic balance.  The wind therefore is no longer moving directly from the high pressure region to the low pressure region, and it is for this reason that the pressure gradients do not dissipate straight away. (See friction force below)&lt;/strong&gt;  This can be represented by the picture below, and I will include the formula when we have access to mathjax (note the Coriolis term is represented a bit differently in this diagram, but don't worry I'll explain how it is the same when mathjax is added - basically it just a certain direction component of my more generalized vector above):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/kldE3.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;3. Friction&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I mentioned previously, the geostrophic balance presumes the absence of friction.  In reality, friction acts to slow the flow of wind, in turn lessening the influence of the Coriolis effect. Thus ultimately the wind does tend to spirally slightly inwards towards the low pressure zone.  The effect of friction is more noticeable in the lower atmosphere, and in the upper troposphere the geostrophic motion approximation is more accurate, and therefore the pressure gradients will take longer to dissipate in the upper atmosphere than the lower atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The force of friction is given by:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$F = cV$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $c$ is a constant, and $V$ is the velocity of the wind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;4.  Gravity&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pressure gradients can also be sustained vertically, due to the influence of gravity.  When the force of gravity balances the pressure gradient, this situation is known as hydro-static wind balance, and is represented by the equation:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$dP/dz = -{\rho}g$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\rho$ is density of air, and $g$ is the acceleration due to gravity, which is approximately $9.8 m s^{-2}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Net Effect:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While I have already answered the question, I have decided include the equation combining all 4 forces for completeness.  Combining all these forces acting on the wind, the net acceleration of wind can be determined by the equation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\frac{D\boldsymbol{U}}{Dt}=-2\Omega\times\boldsymbol{U}-\frac{1}{\rho}{\nabla}p+\boldsymbol{g}+\boldsymbol{F}_r$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\boldsymbol{U}$ represents the velocity of the wind, and $t$ represents time.  The quantities in bold are vectors, and act in a specified direction.  (e.g. $\boldsymbol{g}$ acts vertically, where as $\boldsymbol{F}$ acts in the opposite direction to $\boldsymbol{U}$).  Below is in image of this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/aT67I.jpg&quot; alt=&quot;enter image description here&quot;&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This image shows how the forces act (excluding gravity) around high and low pressure zones.  PGF is the pressure gradient force, CF is the psuedo-Coriolis force and F is the frictional force opposing the velocity of the wind.  Note that the wind moves slightly in wards towards the low pressure region, rather than perpendicular to the gradient predicted by geostrophic motion.  This is due to the frictional force.&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="-1" LastEditDate="2017-04-13T12:40:15.470" LastActivityDate="2014-11-28T08:17:39.017" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="452" PostTypeId="2" ParentId="108" CreationDate="2014-04-23T09:33:47.683" Score="15" Body="&lt;p&gt;Actually, the reason why the Earth is not a sphere is twofold:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;the Earth is rotating and has been rotating for a long time&lt;/li&gt;&#xA;&lt;li&gt;the Earth is not perfectly rigid, it can even be considered as a viscous fluid on long timescales&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;If the Earth were not rotating, it would be a sphere.&#xA;If the Earth had started to rotate very recently, it wouldn't be at equilibrium, thus probably not the ellipsoid of revolution we are familiar with.&#xA;Last but not least, if the Earth were perfectly rigid, it wouldn't be deformed by any process, including rotation, thus still have its initial shape.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can consider that the Earth is a fluid in hydrostatic equilibrium (i.e. a fluid at rest) at each point, taking into account both the effect of gravity and centrifugal (pseudo) force due to rotation. Then, if we look for the shape of the Earth's surface under this condition, the solution is an ellipsoid of revolution. It is very close to the actual Earth's surface which is a good evidence that our initial assumption -- rotating fluid in hydrostatic equilibrium -- is reasonable for long timescale.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The study of this question is related to the famous Clairaut's equation from the name of the famous French scientist who published the treatise &lt;em&gt;Théorie de la figure de la terre&lt;/em&gt; at the end of the 18th century.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NB: if we just explain the bulge at the equator referring to the effect of the centrifugal pseudo force and ignoring the hydrostatic equilibrium issue, we should conclude that the polar radius is the same with or without rotation. Though, it is smaller: about 6357 km vs 6371 km for a spherical Earth of equal volume.&lt;/p&gt;&#xA;" OwnerUserId="114" LastActivityDate="2014-04-23T09:33:47.683" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="453" PostTypeId="1" CreationDate="2014-04-23T11:00:20.747" Score="18" ViewCount="229" Body="&lt;p&gt;Heat is transferred from the interior to the surface through several methods. One is simply the conduction of sensible heat through the crust - I would guess this accounts for most of it. But some is also transferred through another route: when crust is subducted, it becomes dehydrated, which absorbs heat. Elsewhere, new crust is created and becomes hydrated, which releases heat. The net effect is the transfer of heat from the interior to the surface, but it is transferred in the form of hydration enthalpy rather than sensible heat. A similar process is serpentinisation, which transfers energy in the form of chemical bonds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm looking for data about the total (net) amount of energy that is transferred from the interior to the surface in the form of hydration enthalpy and heat of serpentinisation, as opposed to sensible heat? Is it a substantial fraction of the total ~45TW figure?&lt;/p&gt;&#xA;" OwnerUserId="215" LastActivityDate="2018-12-17T03:20:11.933" Title="How much heat is transported from the interior to the surface in the form of hydration enthalpy?" Tags="|geophysics|plate-tectonics|geothermal-heat|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="454" PostTypeId="2" ParentId="246" CreationDate="2014-04-23T11:50:59.167" Score="13" Body="&lt;p&gt;There is one vaguely plausible method that has been proposed: blow open a crack in the Earth's crust using a hydrogen bomb and then fill the crack with molten iron. The iron then sinks to the core, and a small probe can sit on top of it and ride it all the way down. There's no way to get it back again, of course, but it could transmit its data back to the surface using seismic waves. (We have detectors sensitive enough to pick them up.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although it's a pretty crazy idea, it was published in Nature magazine by a respected geophysicist, so there's a certain plausibility to it, although I don't think anyone intends to carry the plan out in practice. (Original article: &lt;a href=&quot;http://www.nature.com/nature/journal/v423/n6937/full/423239a.html&quot;&gt;Mission to Earth's core — a modest proposal&lt;/a&gt;, unfortunately paywalled. Googling the title will give a number of press articles about the idea.)&lt;/p&gt;&#xA;" OwnerUserId="215" LastEditorUserId="215" LastEditDate="2014-11-06T13:51:22.747" LastActivityDate="2014-11-06T13:51:22.747" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="455" PostTypeId="2" ParentId="388" CreationDate="2014-04-23T11:55:32.400" Score="13" Body="&lt;p&gt;The Hadley cell was proposed and works only for a non-rotating earth. When we consider the earth's spin, we have to consider the Coriolis force as well. Because of this force air cannot travel in one unhindered cell from the equator to pole or back. So there must be an odd number of cells together so that the air rising and falling in the adjacent cells is oriented in the proper direction. Considering the various observations of the Easterly and Westerly trade winds a 3 cell model best explains our atmospheric circulation. The location of the majority of earth's driest and arid regions are located in the areas underneath the descending branches of the Hadley circulation around 30 degrees latitude, which also supports the 3 cell model. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also watch this video which gives a great explanation to all of your questions with the help of practical experiment and animations.&#xA;&lt;a href=&quot;http://youtu.be/WXuGYSM2D8k&quot;&gt;Atmospheric Circulation Video&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="206" LastActivityDate="2014-04-23T11:55:32.400" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="456" PostTypeId="2" ParentId="369" CreationDate="2014-04-23T12:45:11.453" Score="7" Body="&lt;p&gt;I'm not a tectonicist or a science historian, but as far as I know the ‘pole flight force’ or Polfluchtkraft was introduced by Wegener in his theory of continental drift. Essentially it's just the application of centrifugal force to continents (or, if we are now considering it within the plate tectonic paradigm, to plates). As stated in the Wikipedia article you link to, this force is far too weak to account for plate motions, and this very fact was one of the reasons for the scientific community's rejection of continental drift. Modern tectonics doesn't seem to consider it even as a measurable contributing factor. The only modern references I've found to it have been in historical contexts, such as in Krause (2007). The subtitle of this paper, ‘Vergessene Begriffe der Geologiegeschichte’, translates to ‘forgotten concepts of geological history’, and as far as I can tell this is an accurate summary of Polflucht's current status.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Krause, R.A., 2007. Die Polfluchtkraft: Der LELY-Versuch&#xA;– Vergessene Begriffe der Geologiegeschichte. &lt;em&gt;Polarforschung&lt;/em&gt; 76 (3), 133–140. DOI: 10013/epic.29962&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2015-11-16T16:28:39.503" LastActivityDate="2015-11-16T16:28:39.503" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="457" PostTypeId="2" ParentId="446" CreationDate="2014-04-23T14:55:13.077" Score="39" Body="&lt;p&gt;Ice grows in many forms.  As mentioned in the other answer, all of the ice we are going to observe is &lt;a href=&quot;http://en.wikipedia.org/wiki/Ice_Ih&quot; rel=&quot;noreferrer&quot;&gt;Ice Ih&lt;/a&gt;, but there are many other forms.  See this phase diagram of water:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/k9Ths.png&quot; alt=&quot;Phase diagram of water&quot;&gt;&lt;br&gt;&#xA;&lt;sub&gt;Image courtesy of &lt;a href=&quot;http://commons.wikimedia.org/wiki/User:Cmglee&quot; rel=&quot;noreferrer&quot;&gt;Cmglee&lt;/a&gt; on &lt;a href=&quot;http://en.wikipedia.org/wiki/File:Phase_diagram_of_water.svg&quot; rel=&quot;noreferrer&quot;&gt;wikipedia&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The different ice regimes grow different crystalline shapes.  Ice Ih grows hexagonal crystals and in certain regimes you can find triangular and cubic ice crystals.  The hexagonal shape is a consequence of the bond angles within the water molecule as it forms into a solid crystal lattice.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This phase diagram says we'll experience Ice Ih between 0 C and -100 C and throughout tropospheric pressures.  This ice crystal is hexagonal, but within this crystal form there are many ice habits of crystal growth.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/lOwcY.jpg&quot; alt=&quot;ice habits&quot;&gt;&lt;br&gt;&#xA;&lt;sub&gt;Image used from Weatherwise magazine, AMS&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The axes of this plot are supersaturation with respect to ice ($e/e_{si} &amp;gt; 1$) and temperature.  All of of these crystals are hexagonal but some are long skinny hexagonal prisms and some are very thin and wide hexagonal plates.  The snowflake is a dendrite and these crystals grow between -10 and -22 C in and supersaturation with respect to liquid water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What happens is that the hexagonal crystal has 6 vertices connecting its 6 edges.  These vertices produce an increased gradient in vapor (indeed, the sharper the angle, the stronger the vapor gradient becomes).  At high supersaturations vapor is quickly deposited in the areas of the enhanced vapor gradient and the arms of the dentrite form.  The particular shape of the dendrite will depend strongly on the vapor gradient it is experiencing, which in turn is influenced strongly by its current shape and the environment it is growing in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Lamb, D. and Verlinde, H., 2011: Vapor-growth of individual ice crystals. &lt;em&gt;&lt;a href=&quot;http://ebooks.cambridge.org/ebook.jsf?bid=CBO9780511976377&quot; rel=&quot;noreferrer&quot;&gt;Physics and Chemistry of Clouds&lt;/a&gt;&lt;/em&gt;. Cambridge University Press, Ch 8.3, 342-369.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-04-23T14:55:13.077" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="458" PostTypeId="2" ParentId="428" CreationDate="2014-04-23T15:28:55.990" Score="13" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Could all the drilling and digging to use the earth's natural heat as geothermal energy be affecting Earth's core, causing it to cool down?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes. But by how much? Let's do some rough math.  We'll just be concerned with orders of magnitude here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Suppose we have a uniform sphere the size of the Earth. Call it 10&lt;sup&gt;21&lt;/sup&gt; cubic meters. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Suppose this sphere is made of rock that is four times more dense than water. Water weighs 1000 kg per cubic meter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course the Earth is not uniform; it is made up of rocks that are less dense and metals which are more dense. We're doing some rough math here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And let's suppose that the interior of our planet is of uniform temperature, say, 5000 Kelvin. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Again, of course the Earth is not uniformly hot throughout. Again, we're doing rough math here, just to get an idea of the order of magnitude involved.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's suppose that our ball of rock is not producing new heat. Of course the Earth is producing new heat inside it, for instance, from radioactive elements in the core. But let's suppose that it is not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And let's suppose that our ball of rock has a specific heat capacity of 0.8 joules per kilogram * kelvin.  The specific heat capacity roughly speaking tells us how much energy is in some amount of a substance at a particular temperature.  So multiply that out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(10&lt;sup&gt;21&lt;/sup&gt; cubic meters) x &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(4000 kg / cubic meter) x &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(5000 kelvin) x &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(0.8 Joules per kilogram * kelvin) = &lt;/p&gt;&#xA;&#xA;&lt;p&gt;1.6 x 10&lt;sup&gt;28&lt;/sup&gt; joules&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We're just looking for an order of magnitude here. Our ball of rock has roughly 10&lt;sup&gt;28&lt;/sup&gt; joules of thermal energy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now let's suppose that we extract some amount of those joules.  Total energy consumption of humanity from all sources -- nuclear, gas, etc -- is about 10&lt;sup&gt;18&lt;/sup&gt; joules per year.  If we got 100% of that from our ball of hot rock, it would cool it off by one-ten-billionth of its total heat every year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's making the worst possible assumptions; of course we do not get anywhere even close to all our power from geothermal, the energy we do get was just going to be wasted into the atmosphere eventually anyway, the earth does make its own heat, and so on. We could get our total power needs met by geothermal energy for &lt;em&gt;trillions&lt;/em&gt; of years without worrying about cooling the core.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;how does it retain its heat?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The same way anything other ball of rock retains its heat. Heat, like all forms of energy, is retained indefinitely until something acts to remove it. I'm not clear on what question you're actually asking here.&lt;/p&gt;&#xA;" OwnerUserId="225" LastEditorUserId="225" LastEditDate="2014-04-23T15:40:35.860" LastActivityDate="2014-04-23T15:40:35.860" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="459" PostTypeId="2" ParentId="224" CreationDate="2014-04-23T15:44:35.573" Score="5" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Each float costs around US$15,000 and communication, deployment and calibrations costs approximately double the through-life cost of each float.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;(from &lt;a href=&quot;http://www.argo.ucsd.edu/Argoflyer_final.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.argo.ucsd.edu/Argoflyer_final.pdf&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;One can roughly estimate from this source, given a life-span of four years, an Argo float costs slightly over \$3.5k/yr (float only) or \$7k/yr (including deployment and calibration etc.).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;...by June 2007, over 95 percent of the goal of 3,000 floats had been deployed...&lt;/p&gt;&#xA;&lt;p&gt;...With a four-year life span per float ...&lt;/p&gt;&#xA;&lt;p&gt;...The annual cost of the worldwide Argo program is about $20 million...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;(from &lt;a href=&quot;http://celebrating200years.noaa.gov/magazine/argo/welcome.html#float&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://celebrating200years.noaa.gov/magazine/argo/welcome.html#float&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;Based on this source all inclusive number will be in the ball park of slightly less than \$7k/yr.&lt;/p&gt;&#xA;&lt;p&gt;So, without getting into details of whether one can be an alternative to another technically, a primitive cost comparison based on the yearly cost derived from the mentioned article and the links below it is ~7k\$/yr (including deployment and calibration etc.) or ~3.5k/yr (only the float) vs versus \$4k per tag with Tarpon fish. So if one can assume the deployment/retrieval/calibration costs are similar they will cost about the same by the end of first year. After one year the annual cost of a fish tag will keep getting cheaper and cheaper than a float until the end of its life-span.&lt;/p&gt;&#xA;" OwnerUserId="120" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-05-14T03:27:23.407" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="460" PostTypeId="2" ParentId="446" CreationDate="2014-04-23T15:57:19.580" Score="19" Body="&lt;p&gt;To add to both Spießbürger's and casey's excellent answers, &lt;a href=&quot;http://en.wikipedia.org/wiki/Hydrogen&quot; rel=&quot;noreferrer&quot;&gt;hydrogen&lt;/a&gt; bonds are the reason why some snowflakes are six-sided. His was alluded to, but I think it could use a bit more extrapolation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ta91T.gif&quot; alt=&quot;Enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;www.physicsofmatter.com&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The image above shows an &lt;a href=&quot;http://en.wikipedia.org/wiki/Oxygen&quot; rel=&quot;noreferrer&quot;&gt;oxygen&lt;/a&gt; atom bonding with two hydrogen atoms (water). We can call these covalent bonds for our purposes, although hydrogen bonds tend, in some cases (and especially water) have special properties that make it unique from other covalent bonds. The result of this bond is a slightly negative charge near the oxygen atom and slightly positive near the hydrogens. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What happens next is that two water molecules will build up in a specific way, relating to their charge: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Lm6Gu.png&quot; alt=&quot;&quot;&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;www.doublexscience.org&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You see, as Spießbürger mentioned, the dipole of the water molecule allows the water molecules to build up in the shape pictured above, over and over and over. This happens naturally, since when water freezes, it forces the molecules to get closer together (but interestingly enough, the end result makes ice less dense than its liquid form). As these molecules build up, you start seeing a crystal lattice:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/4PZ3r.jpg&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;www.doublexscience.org&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With each ring in the crystal lattice having six side. Each point is an oxygen atom. Each side is side is a hydrogen bonding with an oxygen. The snow flake, is just this bonding happening many many times.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So while it might not seem so obvious, we can explain the nature of the hexagonal structure with highschool/middle school level chemistry. &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="502" LastEditDate="2014-05-21T19:47:32.883" LastActivityDate="2014-05-21T19:47:32.883" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="461" PostTypeId="2" ParentId="168" CreationDate="2014-04-23T16:01:44.067" Score="5" Body="&lt;p&gt;So far this has been the most suitable answer to my question... &lt;/p&gt;&#xA;&#xA;&lt;p&gt;NOAA's National Oceanographic Data Center has posted NetCDF Templates v1.0 the CDL templates on their &lt;a href=&quot;http://www.nodc.noaa.gov/data/formats/netcdf/&quot; rel=&quot;noreferrer&quot;&gt;web site&lt;/a&gt;. These can be used with &lt;a href=&quot;http://nco.sourceforge.net/&quot; rel=&quot;noreferrer&quot;&gt;netCDF Operator (NCO) commands&lt;/a&gt; to create &lt;a href=&quot;http://cf-convention.github.io/index.html&quot; rel=&quot;noreferrer&quot;&gt;Climate and Forecast (CF)&lt;/a&gt; compliant files. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nodc.noaa.gov/data/formats/netcdf/&quot; rel=&quot;noreferrer&quot;&gt;http://www.nodc.noaa.gov/data/formats/netcdf/&lt;/a&gt; &lt;br&gt;&#xA;&lt;a href=&quot;http://nco.sourceforge.net/&quot; rel=&quot;noreferrer&quot;&gt;http://nco.sourceforge.net/&lt;/a&gt; &lt;br&gt;&#xA;&lt;a href=&quot;http://cf-convention.github.io/index.html&quot; rel=&quot;noreferrer&quot;&gt;http://cf-convention.github.io/index.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="120" LastActivityDate="2014-04-23T16:01:44.067" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="462" PostTypeId="2" ParentId="368" CreationDate="2014-04-23T17:15:43.253" Score="10" Body="&lt;p&gt;No, it did not definitively single-handedly cause the KT mass extinction event. Around the same time, the Deccan Traps Large Igneous Province (India) was being emplaced. Flood volcanism has been associated with other mass extinctions, due to the impact on climate, sunlight at the surface, etc, of the output of huge volumes of sulphur-based gases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Chicxulub impact probably didn't hurt the extinction, but the large particulate material it distributed in the atmosphere would have sedimented out again entirely within a handful of years. Meanwhile, the Deccan Traps contain sediment layers intercalated between lava flows, some of which contain fossilised dinosaur eggs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reasons for mass extinctions (and whether they actually occur at all, as distinct identifiable events) remain poorly understood, but we're pretty sure the meteorite impact wasn't the only thing that did for the dinosaurs.&lt;/p&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-04-23T17:15:43.253" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="463" PostTypeId="2" ParentId="418" CreationDate="2014-04-23T17:26:03.743" Score="6" Body="&lt;p&gt;Existing plates can and do split: see, for example, the ridge-ridge-ridge triple junction at the Red Sea/Gulf of Aden/East African Rift Zone, though plate splitting is also fundamental to the breakup of megacontinents such as Gondwana.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plates form as part of the Earth's convective system: they're fundamental to heat transport in the mantle. When plate tectonics started up is still under debate, but the mechanism is pretty well understood. A cooling magma ocean will start to form a blocky surface (if you want a human-scale analogue, check out videos of Mount Erebus' permanent lava lake, or of Hawai'ian a'a flows). The mantle contains just enough water to act as a lubricant and promote formation of shear zones, allowing these plates to continue moving past one another as opposed to locking up (whereas Venus' water concentrations are too low, hence its lack of plate tectonics).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Continental and oceanic lithosphere do behave differently - in particular, it's in general much harder to point at distinct &quot;plates&quot; in continental lithosphere, in part because it survives much longer (the oldest oceanic crust is ca 250Ma) and thus has a much more complex history with respect to suturing/breaking up - think the growth of the Himalaya. My understanding is that the details of the formation of continental lithosphere, as opposed to oceanic lithosphere, are still an area of active research.&lt;/p&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-04-23T17:26:03.743" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="464" PostTypeId="2" ParentId="418" CreationDate="2014-04-23T17:31:05.997" Score="22" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is there a theory on how the Earth's plates were initially formed?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The answer to this is has roots in another question you asked about the differences between continental crust and oceanic crust. &lt;a href=&quot;http://www.annualreviews.org/doi/abs/10.1146/annurev-earth-060313-055016&quot; rel=&quot;noreferrer&quot;&gt;Carlson et al. (2014)&lt;/a&gt; just put out an excellent review of what we know about Earth and how it formed through time. I am using it as a guide and source for much of this post.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just recently an age of a zircon was determined to be 4.374 Ga (&lt;a href=&quot;http://www.news.wisc.edu/22568&quot; rel=&quot;noreferrer&quot;&gt;Valley et al., 2014&lt;/a&gt;) using U-Pb geochronology. The age of the Earth is 4.54 ± 0.05 Ga. This new result suggests that granitic and felsic magma was already present on Earth only after ~160 million years after the Earth formed. Some other interesting dates is the Moon formation between 4.4 to 4.45 Ga and, based on xenon isotopes, the separation of the atmosphere from the solid Earth is thought to happen around 4.45 Ga.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;After the formation of the Earth, the core formed, thereby creating a metallic inner core and the primitive outer mantle. The Earth began to cool and differentiate and thereby form a crust. Different models suggest a range of possibilities such as a quasi-stable quench crust of peridotitic/komatiitic composition (Smith, J.V., 1981) to a very evolved composition approaching tonalite (Harrison,T.A., 2009).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question now is this crust now a plate or rather, similar to the lithosphere as we know it today?  The lithosphere is defined as the brittle outer layer of the Earth and plates are segments of the lithosphere and the base of it is called the Mohorovičić discontinuity, which generally defines the contact between the lithosphere and the upper mantle. It is interesting to think about when these features may have formed as the Earth's outer crust is forming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is an entire GSA Special Paper volume on the subject of &lt;a href=&quot;http://specialpapers.gsapubs.org/content/440.toc&quot; rel=&quot;noreferrer&quot;&gt;'When Did Plate Tectonics Begin on Planet Earth?'&lt;/a&gt;. There is a range of evidence suggesting that plate tectonics as we know it today initiated at the latest around ~3 Ga to as late as ~1 Ga (Condie &amp;amp; Kröner, 2008). Below is a table from that paper that outlines indicators of plate tectonics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Wq120.png&quot; alt=&quot;Table from (Condie &amp;amp; Kröner, 2008) that reviews evidence of plate tecotnics.&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The outer crust of Earth is likely not stationary, but possibly being dragged along the paths of mantle convection. These brittle segments begins colliding into one another and building upwards while other portions are subducted beneath other plate segments. The convecting mantle causes mantle material to be brought up from depth to conditions at lower pressures, which cause the mantle to melt (this is called adiabatic melting). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There was a paper just recently published in Nature by &lt;a href=&quot;http://www.nature.com/doifinder/10.1038/nature13072&quot; rel=&quot;noreferrer&quot;&gt;Bercovici and Ricard(2014)&lt;/a&gt; where they try to answer the question as to why we see geological evidence of proto-subduction at 4 Ga with for prominent subduction features appearing around 3 Ga. I suggest reading the abstract on the papers website but they suggest that ...&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;when sufficient lithospheric damage combines with transiet mantle&#xA;  flow and migrating proto-subduction, it leads to the accumulation of&#xA;  weak plate boundaries and eventually to fully formed tectonic plates&#xA;  driven by subduction alone. - Bercovici and Ricard (2014)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;On the composition of the crust...&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most incompatible elements in the mantle (e.g. lithophile elements [K,Na, Nd] and high field strength elements [U,Th]) will go into the liquid melt and move towards the surface of the Earth and either erupt on the surface or be stored in a magma chamber and further fractionate or differentiate to more felsic magma compositions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Through time, all of these processes will generate different pieces of crust formed from different sources and at varying conditions and later become altered due to either chemical or physical metamorphism. Each of the continents we have today are pieced together from the separation and collision of other tectonic plates. For example, Pangaea was formed due to the collision of many different plates, I am not sure if Pangaea was then considered one giant plate, but it then broke apart and separated. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is it possible for existing plates to split into two distinct plates?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The East African Rift is currently a divergent boundary within the African Plate. So the answer is yes.&lt;/p&gt;&#xA;" OwnerUserId="188" LastEditorUserId="188" LastEditDate="2014-04-24T17:03:01.503" LastActivityDate="2014-04-24T17:03:01.503" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="465" PostTypeId="2" ParentId="428" CreationDate="2014-04-23T17:47:40.840" Score="4" Body="&lt;p&gt;You have to start with the cause of the heat: radioactive isotopes are distributed throughout the earth and, since thermal radiation occurs at the surface, the deeper you go the hotter it gets. Radioactive isotopes decay at a fixed rate and some have very long half lives so this heat is released over the lifespan of the earth. The earth's heat is not (mostly?) due to kinetic energy left over from its formation or tidal squeezing by the moon. Because of the scale nothing we do will make much difference to this situation. &lt;/p&gt;&#xA;" OwnerDisplayName="user231" LastEditorDisplayName="user231" LastEditDate="2014-05-03T06:11:11.400" LastActivityDate="2014-05-03T06:11:11.400" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="466" PostTypeId="2" ParentId="94" CreationDate="2014-04-23T18:02:02.830" Score="2" Body="&lt;p&gt;Mostly it's due to radioactive isotopes distributed throughout the earth decaying at rates corresponding to their half lives - some of which are very long. We lose heat from the surface so the centre is hot. NB Just found out there is some tidal squeezing by the moon on the earth, but it's minimal compared to Io for example.&lt;/p&gt;&#xA;" OwnerDisplayName="user231" LastEditorDisplayName="user231" LastEditDate="2014-05-03T06:08:25.903" LastActivityDate="2014-05-03T06:08:25.903" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="467" PostTypeId="2" ParentId="428" CreationDate="2014-04-23T18:40:08.690" Score="13" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;... causing it to cool down?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This &lt;a href=&quot;https://physics.stackexchange.com/a/80169/1989&quot;&gt;answer&lt;/a&gt; to the question 'Why has Earth's core not become solid?' over on Physics seems to claim the answer is no. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The core is heated by radioactive decays of Uranium-238, Uranium-235, Thorium-232, and Potassium-40, all of which have half-lives of greater than 700 million years (up to about 14 billion years for Thorium).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The core isn't hot just because of remnant heat left over from formation, the heat energy in the core is continually renewed by radioactive processes. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If so, would it result in an ice age?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This energy from the core must already be continually dissipated up through the mantle, through the crust, into the atmosphere and eventually into space (or else the planet would be heating up). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;All we could possibly do is speed the dissipation of this energy through the crust, any energy we extract would get to the surface anyway.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As others have pointed out geothermal energy is a tiny fraction of what heats our atmosphere, most of that comes from the sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even if this were not the case, for us to cause an ice age, would require us to have near complete control over geothermal release through artificial means.&#xA;We would have to extract enough energy over a long enough period from deep enough in the earth that there was no longer significant natural heat dispersion through the crust.&#xA;Then we would have to stop and bottle up our manual extraction so that the heat had no other means to escape but rising through the crust in the natural way. The heat present in the atmosphere would dissipate into space far quicker than new heat would rise through the crust.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I imagine both the process of our intervening to the point of control, and our sudden relinquishing control would both have significant effects aside from climate change: earthquakes, volcanic eruptions, disrupting continental drift... &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If not, how does it retain its heat?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I hope it is clear that it doesn't. &lt;/p&gt;&#xA;" OwnerUserId="230" LastEditorUserId="-1" LastEditDate="2017-04-13T12:40:15.470" LastActivityDate="2014-12-24T07:13:27.830" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="468" PostTypeId="5" CreationDate="2014-04-23T23:53:47.397" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-23T23:53:47.397" LastActivityDate="2014-04-23T23:53:47.397" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="469" PostTypeId="4" CreationDate="2014-04-23T23:53:47.397" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-23T23:53:47.397" LastActivityDate="2014-04-23T23:53:47.397" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="470" PostTypeId="5" CreationDate="2014-04-23T23:56:41.213" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-23T23:56:41.213" LastActivityDate="2014-04-23T23:56:41.213" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="471" PostTypeId="4" CreationDate="2014-04-23T23:56:41.213" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-23T23:56:41.213" LastActivityDate="2014-04-23T23:56:41.213" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="472" PostTypeId="5" CreationDate="2014-04-23T23:59:54.207" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-23T23:59:54.207" LastActivityDate="2014-04-23T23:59:54.207" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="473" PostTypeId="4" CreationDate="2014-04-23T23:59:54.207" Score="0" Body="Oceanography is the branch of Earth science that studies the ocean. It is also known as oceanology." OwnerUserId="111" LastEditorUserId="111" LastEditDate="2014-08-15T20:22:15.957" LastActivityDate="2014-08-15T20:22:15.957" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="474" PostTypeId="5" CreationDate="2014-04-24T00:00:28.650" Score="0" Body="&lt;p&gt;The field of volcanology includes study of the formation, distribution, and classification of volcanoes; their structures; the types of material erupted (e.g. lava, ash, pyroclastic flows, gases); research into relationships between volcanic eruptions and other large-scale geologic processes; and eruption prediction.&lt;/p&gt;&#xA;" OwnerUserId="105" LastEditorUserId="105" LastEditDate="2014-04-30T20:16:09.303" LastActivityDate="2014-04-30T20:16:09.303" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="475" PostTypeId="4" CreationDate="2014-04-24T00:00:28.650" Score="0" Body="The properties and behaviour of volcanoes, from the genesis of magmas to their ascent and emission at the surface of the Earth (or other planetary environments)." OwnerUserId="105" LastEditorUserId="18081" LastEditDate="2019-11-26T17:07:50.897" LastActivityDate="2019-11-26T17:07:50.897" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="476" PostTypeId="5" CreationDate="2014-04-24T00:02:20.247" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:02:20.247" LastActivityDate="2014-04-24T00:02:20.247" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="477" PostTypeId="4" CreationDate="2014-04-24T00:02:20.247" Score="0" Body="Geodynamics is the application of mathematics, physics, chemistry, geology, and computer science in understanding how mantle convection leads to plate tectonics." OwnerUserId="-1" LastEditorUserId="32" LastEditDate="2015-07-27T07:44:09.623" LastActivityDate="2015-07-27T07:44:09.623" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="478" PostTypeId="5" CreationDate="2014-04-24T00:03:00.633" Score="0" Body="&lt;p&gt;Seismology is the scientific study of earthquakes. Earthquakes have various source mechanisms (tectonic, volcanic, or even artificial mechanisms such as explosions) which all produce elastic waves that propagate through Earth's materials. Those waves are recorded by seismometers and the data is used to characterize earthquakes (location, magnitude, etc.).&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2019-12-20T04:29:44.913" LastActivityDate="2019-12-20T04:29:44.913" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="479" PostTypeId="4" CreationDate="2014-04-24T00:03:00.633" Score="0" Body="For questions about the study of earthquakes and various seismic sources." OwnerDisplayName="user13" LastEditorDisplayName="user13" LastEditDate="2014-05-01T21:53:47.520" LastActivityDate="2014-05-01T21:53:47.520" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="480" PostTypeId="5" CreationDate="2014-04-24T00:10:56.410" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:10:56.410" LastActivityDate="2014-04-24T00:10:56.410" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="481" PostTypeId="4" CreationDate="2014-04-24T00:10:56.410" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:10:56.410" LastActivityDate="2014-04-24T00:10:56.410" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="482" PostTypeId="5" CreationDate="2014-04-24T00:11:31.777" Score="0" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;carbon cycle&lt;/a&gt; is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Biogeochemical_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;biogeochemical&lt;/a&gt; cycle which transports carbon around the earth. This is mediated by a range of different processes which result in the uptake, release, and storage of carbon in different chemical states.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a good introduction on the &lt;a href=&quot;https://earthobservatory.nasa.gov/features/CarbonCycle/page1.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA Earth Observatory webpage&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Questions with this tag may be about specific processes and fluxes within the carbon cycle (though other more specialised tags may be more appropriate in some cases) - or about how human activities change the direction, magnitude, and rate of processes.&lt;/p&gt;&#xA;" OwnerUserId="18621" LastEditorUserId="18621" LastEditDate="2020-01-06T06:27:09.667" LastActivityDate="2020-01-06T06:27:09.667" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="483" PostTypeId="4" CreationDate="2014-04-24T00:11:31.777" Score="0" Body="Questions about the absorption and release of carbon due to natural biogeochemical processes, and human interactions with the carbon cycle." OwnerUserId="18621" LastEditorUserId="18621" LastEditDate="2020-01-06T06:27:13.500" LastActivityDate="2020-01-06T06:27:13.500" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="484" PostTypeId="5" CreationDate="2014-04-24T00:12:20.177" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:12:20.177" LastActivityDate="2014-04-24T00:12:20.177" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="485" PostTypeId="4" CreationDate="2014-04-24T00:12:20.177" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:12:20.177" LastActivityDate="2014-04-24T00:12:20.177" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="486" PostTypeId="5" CreationDate="2014-04-24T00:13:15.163" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:13:15.163" LastActivityDate="2014-04-24T00:13:15.163" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="487" PostTypeId="4" CreationDate="2014-04-24T00:13:15.163" Score="0" Body="An objective measure of hot and cold, typically measured by a thermometer." OwnerUserId="192" LastEditorUserId="6298" LastEditDate="2019-02-06T03:16:44.270" LastActivityDate="2019-02-06T03:16:44.270" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="488" PostTypeId="2" ParentId="391" CreationDate="2014-04-24T00:13:43.857" Score="10" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;I've heard that gold ore is often associated with quartz veins. What&#xA;  geological processes enable gold particles to naturally cluster&#xA;  together like this?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;First of all, gold is mostly found in quartz veins in and around igneous intrusions.&lt;br&gt;&#xA;It happens with a very hot hydro-thermal fluid of silica, oxygen and concentrated gold that is created during incidences of compressional forces acting on the crust. It is then released at the end of magma crystallization and fills cracks and voids in the surrounding rock. This fluid then solidifies to form gold-rich (and also other metals like silver) quartz veins.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What characteristics/properties should I look out for on the surface&#xA;  of a rock that are likely to yield gold within it?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm not sure of any way to tell on the outside of a rock except maybe if it is igneous and you see signs of a quartz vein.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Are there remote sensors that I use to detect the presence of gold in&#xA;  a rock?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There are many metal detectors that have a frequency you can set them to that can detect gold.&lt;/p&gt;&#xA;" OwnerUserId="115" LastEditorUserId="181" LastEditDate="2014-05-23T02:36:06.863" LastActivityDate="2014-05-23T02:36:06.863" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="489" PostTypeId="5" CreationDate="2014-04-24T00:13:47.103" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:13:47.103" LastActivityDate="2014-04-24T00:13:47.103" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="490" PostTypeId="4" CreationDate="2014-04-24T00:13:47.103" Score="0" Body="Terminology is the study of terms and their use. Terms are words and compound words that in specific contexts are given specific meanings, meanings that may deviate from the meaning the same words have in other contexts and in everyday language." OwnerUserId="116" LastEditorUserId="116" LastEditDate="2014-04-24T16:36:57.767" LastActivityDate="2014-04-24T16:36:57.767" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="491" PostTypeId="5" CreationDate="2014-04-24T00:14:20.650" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:14:20.650" LastActivityDate="2014-04-24T00:14:20.650" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="492" PostTypeId="4" CreationDate="2014-04-24T00:14:20.650" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:14:20.650" LastActivityDate="2014-04-24T00:14:20.650" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="493" PostTypeId="5" CreationDate="2014-04-24T00:14:55.317" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:14:55.317" LastActivityDate="2014-04-24T00:14:55.317" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="494" PostTypeId="4" CreationDate="2014-04-24T00:14:55.317" Score="0" Body="Questions regarding the height of the ocean's surface." OwnerDisplayName="user13" LastEditorDisplayName="user13" LastEditDate="2014-05-01T22:05:03.140" LastActivityDate="2014-05-01T22:05:03.140" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="495" PostTypeId="5" CreationDate="2014-04-24T00:15:27.930" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:15:27.930" LastActivityDate="2014-04-24T00:15:27.930" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="496" PostTypeId="4" CreationDate="2014-04-24T00:15:27.930" Score="0" Body="Sedimentology encompasses the study of modern sediments such as sand, mud, and clay, and the processes that result in their deposition." OwnerUserId="116" LastEditorUserId="116" LastEditDate="2014-04-24T16:37:19.667" LastActivityDate="2014-04-24T16:37:19.667" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="497" PostTypeId="5" CreationDate="2014-04-24T00:17:17.043" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:17:17.043" LastActivityDate="2014-04-24T00:17:17.043" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="498" PostTypeId="4" CreationDate="2014-04-24T00:17:17.043" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:17:17.043" LastActivityDate="2014-04-24T00:17:17.043" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="499" PostTypeId="5" CreationDate="2014-04-24T00:17:55.720" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:17:55.720" LastActivityDate="2014-04-24T00:17:55.720" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="500" PostTypeId="4" CreationDate="2014-04-24T00:17:55.720" Score="0" Body="Questions regarding the magnetic field emanating from Earth's interior." OwnerDisplayName="user13" LastEditorDisplayName="user13" LastEditDate="2014-05-02T10:48:54.850" LastActivityDate="2014-05-02T10:48:54.850" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="501" PostTypeId="5" CreationDate="2014-04-24T00:19:09.303" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:19:09.303" LastActivityDate="2014-04-24T00:19:09.303" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="502" PostTypeId="4" CreationDate="2014-04-24T00:19:09.303" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:19:09.303" LastActivityDate="2014-04-24T00:19:09.303" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="503" PostTypeId="5" CreationDate="2014-04-24T00:20:31.783" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:20:31.783" LastActivityDate="2014-04-24T00:20:31.783" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="504" PostTypeId="4" CreationDate="2014-04-24T00:20:31.783" Score="0" Body="Questions about rock types, formation, chemistry, and physics." OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2020-10-15T13:19:52.017" LastActivityDate="2020-10-15T13:19:52.017" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="505" PostTypeId="5" CreationDate="2014-04-24T00:21:43.137" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:21:43.137" LastActivityDate="2014-04-24T00:21:43.137" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="506" PostTypeId="4" CreationDate="2014-04-24T00:21:43.137" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:21:43.137" LastActivityDate="2014-04-24T00:21:43.137" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="507" PostTypeId="5" CreationDate="2014-04-24T00:22:15.943" Score="0" Body="&lt;p&gt;When Earth, moon and sun are approximately lining up  (full or new moon) gravitational forces are added up and tides are stronger than usual. You call this phenomenon spring tides.&#xA;When Earth, moon and sun form a right angle  (first or third quarter of moon) gravitational forces partially cancel out each other and tides are weaker than usual. You call this phenomenon neap tides.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Don't mix them up with solar tides in the atmosphere, which are inertia-gravity waves caused by the absorption of solar radiation in the the atmosphere.)&lt;/p&gt;&#xA;" OwnerUserId="6441" LastEditorUserId="6441" LastEditDate="2016-12-02T15:45:09.887" LastActivityDate="2016-12-02T15:45:09.887" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="508" PostTypeId="4" CreationDate="2014-04-24T00:22:15.943" Score="0" Body="Tides are the periodic fall and rise of sea-level due to gravitational forces of the moon, sun or earth-rotation. &#xD;&#xA;When asking questions specifically about tides, use this tag and also include the [ocean], [moon], [sun] or [earth-rotation] tag if appropriate." OwnerUserId="6441" LastEditorUserId="2470" LastEditDate="2016-12-02T13:04:49.773" LastActivityDate="2016-12-02T13:04:49.773" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="509" PostTypeId="5" CreationDate="2014-04-24T00:22:52.983" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:22:52.983" LastActivityDate="2014-04-24T00:22:52.983" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="510" PostTypeId="4" CreationDate="2014-04-24T00:22:52.983" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:22:52.983" LastActivityDate="2014-04-24T00:22:52.983" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="511" PostTypeId="5" CreationDate="2014-04-24T00:23:23.530" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:23:23.530" LastActivityDate="2014-04-24T00:23:23.530" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="512" PostTypeId="4" CreationDate="2014-04-24T00:23:23.530" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:23:23.530" LastActivityDate="2014-04-24T00:23:23.530" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="513" PostTypeId="5" CreationDate="2014-04-24T00:23:56.773" Score="0" Body="&lt;p&gt;An &lt;a href=&quot;https://en.wikipedia.org/wiki/Ice_age&quot; rel=&quot;nofollow noreferrer&quot;&gt;ice age&lt;/a&gt; is a long period of reduction in the temperature of the Earth's surface and atmosphere, resulting in the presence or expansion of continental and polar ice sheets and alpine glaciers.&#xA;This topic relates to questions related to the causes that lead to ice ages, the conditions during such periods and the evidence we have of recent and more ancient ice ages.&lt;/p&gt;&#xA;" OwnerUserId="-1" LastEditorUserId="11908" LastEditDate="2019-02-03T19:17:16.303" LastActivityDate="2019-02-03T19:17:16.303" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="514" PostTypeId="4" CreationDate="2014-04-24T00:23:56.773" Score="0" Body="Questions related to ice ages, including causes, conditions, and evidence." OwnerUserId="-1" LastEditorUserId="11908" LastEditDate="2019-02-03T19:17:16.303" LastActivityDate="2019-02-03T19:17:16.303" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="515" PostTypeId="5" CreationDate="2014-04-24T00:25:03.420" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-24T00:25:03.420" LastActivityDate="2014-04-24T00:25:03.420" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="516" PostTypeId="4" CreationDate="2014-04-24T00:25:03.420" Score="0" Body="Observations recorded on earth. " OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-03-04T13:46:27.743" LastActivityDate="2019-03-04T13:46:27.743" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="517" PostTypeId="1" AcceptedAnswerId="519" CreationDate="2014-04-24T02:10:03.133" Score="35" ViewCount="16108" Body="&lt;p&gt;&lt;strong&gt;From &lt;a href=&quot;http://en.wikipedia.org/wiki/Inner_core&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/strong&gt;&lt;br/&gt;&#xA;Earth's inner core is Earth's innermost part and is a primarily solid ball with a radius of about 1,220 km (760 mi). (This is about 70% of the Moon's radius.) It is believed to consist primarily of an iron–nickel alloy and to be approximately the same temperature as the surface of the Sun: approximately 5700 K (5430 °C).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How do we know what the size of the inner core is?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Bonus Points:&lt;/strong&gt;&#xA;How did we come up with iron-nickel as being the believed constituent for the core?&lt;/p&gt;&#xA;" OwnerUserId="116" LastEditorUserId="543" LastEditDate="2016-01-23T05:34:59.650" LastActivityDate="2018-01-31T02:44:50.697" Title="How can we determine the size and composition of Earth's inner core?" Tags="|geophysics|geodynamics|core|seismology|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="518" PostTypeId="2" ParentId="517" CreationDate="2014-04-24T02:45:30.047" Score="9" Body="&lt;p&gt;Scientists used the seismic waves created by earthquakes bouncing off the core to map out the approximate size of the earth's inner core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The materials that constituted the core were guessed with the thinking that because it was once liquid, the heavier elements like iron and nickel were able to sink down into the center. It probably even has vast amounts of the heaviest elements, like gold, platinum and uranium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reference: &lt;a href=&quot;http://www.universetoday.com/26710/earths-inner-core/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth’s Inner Core&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="115" LastEditorUserId="6093" LastEditDate="2017-01-29T06:29:57.813" LastActivityDate="2017-01-29T06:29:57.813" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="519" PostTypeId="2" ParentId="517" CreationDate="2014-04-24T02:52:29.830" Score="34" Body="&lt;p&gt;We know the the size of the inner core through seismology. From my answer to this question: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/350/how-are-subsurface-wave-speeds-determined-without-subsurface-sensors/351#351&quot;&gt;How are subsurface wave speeds determined without subsurface sensors?&lt;/a&gt;, we can determine the speeds of the different layers of earth. Pictured below is a diagram of raypaths going through the earth from the 1994 Northridge Earthquake in Southern California:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(image from &lt;a href=&quot;http://serc.carleton.edu/NAGTWorkshops/geophysics/seismic11/overview.html&quot; rel=&quot;noreferrer&quot;&gt;http://serc.carleton.edu/NAGTWorkshops/geophysics/seismic11/overview.html&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/xu6wC.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see the earthquake causes many raypaths, some of which go all the layers of Earth. From &lt;a href=&quot;http://en.wikipedia.org/wiki/Huygens%E2%80%93Fresnel_principle&quot; rel=&quot;noreferrer&quot;&gt;Huygen's Principle&lt;/a&gt; we know that there are infinitely many ray paths, meaning that there is a raypath, depending on location, that&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Goes through only the crust&lt;/li&gt;&#xA;&lt;li&gt;Goes through the crust + mantle&lt;/li&gt;&#xA;&lt;li&gt;Goes through the crust + mantle + outer core&lt;/li&gt;&#xA;&lt;li&gt;Goes through the crust + mantle + outer core + inner core&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;and arrives at the same seismometer (probe that measures vibrations, or seismic waves in this case). Depending on the composition of these layers, the ray paths will have different arrival times. The difference between these arrival times are important, we call them lag times, which seismologists can use as a proxy for distance. The lag time between the 3rd and 4th raypath I mentioned above could be used as a proxy for the radius of of the inner core, but we probably would not get a good answer from that. More over, we use this seismic data along with other data types to constrain its size.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can use gravity data to understand get the mass of the earth. See this question for how that can be achieved: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/88/how-is-the-mass-of-the-earth-determined&quot;&gt;How is the mass of the Earth determined?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using the mass of the earth, its size, and assuming that density increases with depth, we can form a seismic wave model (in the first question I linked) which would give us a more accurate lag time to distance conversion. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We also know that Earth is made up of the same stuff as the Sun, by examining its composition through the light spectrum. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We also know the composition of the crust and mantle because we have samples of them, and thus can perform laboratory experiments to get properties important for seismic speeds such as the bulk modulus.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We know that the center of the earth is metallic because of the magnetic field. It was the Trela model that first proposed this. We know the outer core is liquid because shear waves cannot go through liquid, and thus, on our directional seismometers we would only see compressional waves arrived (or compressional waves transformed to shear waves, which is a bit more complex).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Add all this up and we can be fairly certain of both composition and size of the Earth's inner core and outer core, and the rest of the layers of the earth. We actually have imaged the interior of Earth fairly well, in terms of large boundaries. Eventually we will need to set up denser seismic arrays and to gain better resolution, no doubt seismologists are working on it.  &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-04-24T17:11:51.447" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="521" PostTypeId="2" ParentId="12" CreationDate="2014-04-24T04:49:17.947" Score="13" Body="&lt;p&gt;To add to the excellent answer by aretxabaleta:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is what happens for eastward flow over a step change in depth. Note that the wavy pattern is seen from above, and it veers right due to the step and the conservation of potential vorticity (and the fact it is in the Northern Hemisphere). Similar to a particle displaced from its equilibrium in a buoyancy field, the particle veers right towards the latitude that is its new equilibrium point. However, due to its momentum it overshoots the equilibrium latitude. When it returns, the same happens and so on forever (in linear terms), thus giving origin to the wave.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/1uXNm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(from kundu)&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2014-04-24T05:17:49.227" LastActivityDate="2014-04-24T05:17:49.227" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="522" PostTypeId="1" AcceptedAnswerId="524" CreationDate="2014-04-24T06:01:41.097" Score="28" ViewCount="44548" Body="&lt;p&gt;From an aerial view just off the island of Mauritius, there is what appears be an underwater waterfall.  The picture below illustrates this visual phenomenon:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/3JmWC.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The image can also be seen from the google maps satellite &lt;a href=&quot;https://www.google.com/maps/place/Mauritius/@-20.475104,57.312584,3934m/data=!3m1!1e3!4m2!3m1!1s0x217c504df94474c9:0x4203d9c2116bd031&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is responsible for this majestic illusion near the island?  I have heard that it may be sand moving over the edge of an underwater cliff, and if so what causes the sand to be pushed off continuously without the process coming to a stop and what is responsible for this unique geographical landscape allowing this to occur?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="725" LastEditDate="2014-11-30T06:42:40.067" LastActivityDate="2022-11-04T16:32:51.943" Title="What is responsible for the underwater waterfall illusion of Mauritius Island?" Tags="|ocean|sedimentology|ocean-currents|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="523" PostTypeId="2" ParentId="88" CreationDate="2014-04-24T12:40:44.580" Score="42" Body="&lt;p&gt;&lt;em&gt;Note: I updated this answer to include a description of the historical techniques.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Historical Techniques&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Newton developed his theory of gravitation primarily to explain the motions of the bodies that form the solar system. He also realized that while gravity makes the Earth orbit the Sun and the Moon orbit the Earth, it is also responsible for apples falling from trees. Everything attracts everything else, gravitationally. That suggested that one could in theory measure the gravitational attraction between a pair of small spheres. Newton himself realized this, but he didn't think it was very practical. Certainly not two small spheres (Newton 1846):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Whence a sphere of one foot in diameter, and of a like nature to the &#xA;  earth, would attract a small body placed near its surface with a force &#xA;  20000000 times less than the earth would do if placed near its surface; &#xA;  but so small a force could produce no sensible effect. If two such spheres &#xA;  were distant but by 1 of an inch, they would not, even in spaces void of &#xA;  resistance, come together by the force of their mutual attraction in less &#xA;  than a month's time; and less spheres will come together at a rate yet &#xA;  slower, namely in the proportion of their diameters.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Maybe a mountain?&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Nay, whole mountains will not be sufficient to produce any sensible effect. A mountain of an hemispherical figure, three miles high, and six broad, will not, by its attraction, draw the pendulum two minutes out of the true perpendicular : &#xA;  and it is only in the great bodies of the planets that these forces are to be &#xA;  perceived, ...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Newton's idea on the impracticality of such tiny measurements would turn out to be incorrect. Little did Newton know that the scientific revolution that he himself helped propel would quickly make such tiny measurements possible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;&lt;em&gt;Weighing the Earth using mountains&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first attempt to &quot;weigh the Earth&quot; was made during the French geodesic mission to Peru by Pierre Bouguer, Charles Marie de La Condamine, and Louis Godin. Their primary mission was to determine the shape of the Earth. Did the Earth have an equatorial bulge, as predicted by Newton? (The French had sent a different team to Lapland to accomplish the same end.) Bouguer used the trip as an opportunity to test Newton's suggestion that a mountain would deflect a plumb bob from surveyed normal. He chose Chimborazo as the subject mountain. Unfortunately, the measurements came up completely wrong. The plumb bob was deflected, but in the wrong direction. Bouguer measured a slight deflection away from the mountain (Beeson, webpage).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The next attempt was the Schiehallion experiment. While surveying the Mason-Dixon line, Charles Mason and Jeremiah Dixon found that occasionally their calibrations just couldn't be made to agree with one another. The cause was that their plumb bobs occasionally deviated from surveyed normal. This discovery led to the Schiehallion experiment conducted by Nevil Maskelyne. Unlike Bouguer, Maskelyne did get a positive result, a deflection of 11.6 arc seconds, and in the right direction. The observed deflections led Maskelyne to conclude that the mean density of the Earth is 4.713 times that of water (von Zittel 1914).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It turns out that Newton's idea of using a mountain is fundamentally flawed. Others tried to repeat these experiments using other mountains. Many measured a negative deflection, as did Bouguer. There's a good reason for this. For the same reason that we only see a small part of an iceberg (the bulk is underwater), we only see a small part of a mountain. The bulk of the mountain is inside the Earth. A huge isolated mountain should make a plumb bob deviate away from the mountain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;&lt;em&gt;Weighing the Earth using small masses&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if using mountains is dubious, what does that say about the dubiousness of using small masses that would take months to approach one another even if separated by mere inches?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This turned out to be a very good idea. Those small masses are controllable and their masses can be measured to a high degree of accuracy. There's no need to wait until they collide. Simply measure the force they exert upon one another.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This idea was the basis for the Cavendish experiment (Cavendish 1798). Cavendish used two small and two large lead spheres. The two small spheres were hung from opposite ends of a horizontal wooden arm. The wooden arm in turn was suspended by a wire. The two large spheres were mounted on a separate device that he could turn to bring a large sphere very close to a small sphere. This close separation resulted in a gravitational force between the small and large spheres, which in turn caused the wire holding the wooden arm to twist. The torsion in the wire acted to counterbalance this gravitational force. Eventually the system settled to an equilibrium state. He measured the torsion by observing the angular deviation of the arm from its untwisted state. He calibrated this torsion by a different set of measurements. Finally, by weighing those lead spheres Cavendish was able to calculate the mean density of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that Cavendish did not measure the universal gravitational constant G. There is no mention of a gravitational constant in Cavendish's paper. The notion that Cavendish measured G is a bit of historical revisionism. The modern notation of Newton's law of universal gravitation, $F=\frac {GMm}{r^2}$, simply did not exist in Cavendish's time. It wasn't until 75 years after Cavendish's experiments that Newton's law of universal gravitation was reformulated in terms of the gravitational constant G. Scientists of Newton's and Cavendish's times wrote in terms of proportionalities rather than using a constant of proportionality.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The very intent of Cavendish's experiment was to &quot;weigh&quot; the Earth, and that is exactly what he did.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;&lt;strong&gt;Modern Techniques&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the Earth was spherical, if there were no other perturbing effects such as gravitational acceleration toward the Moon and Sun, and if Newton's theory of gravitation was correct, the period of a small satellite orbiting the Earth is given by Kepler's third law: $\left( \frac T {2\pi} \right)^2 = \frac {a^3}{GM_E}$  . Here $T$ is the satellite's period, $a$ is the satellite's semi-major axis (orbital radius), $G$ is the universal gravitational constant, and $M_E$ is the mass of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From this, it's easy  solve for the product $G M_E$ if the period $T$ and the orbital radius $a$ are known: $G M_E = \left( \frac {2\pi} T \right)^2 a^3$. To calculate the mass of the Earth, all one needs to do is divide by $G$. There's a catch, though. If the product is $G M_E$ is known to a high degree of accuracy (and it is), dividing by $G$ will lose a lot of accuracy because the gravitational constant $G$ is only known to four decimal places of accuracy. This lack of knowledge of $G$ inherently plagues any precise measurement of the mass of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I put a lot of caveats on this calculation:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The Earth isn't spherical. The Earth is better modeled as an oblate spheroid. That equatorial bulge perturbs the orbits of satellites (as do deviations from the oblate spheroid model).&lt;/li&gt;&#xA;&lt;li&gt;The Earth isn't alone in the universe. Gravitation from the Moon and Sun (and the other planets) perturb the orbits of satellites. So does radiation from the Sun and from the Earth.&lt;/li&gt;&#xA;&lt;li&gt;Newton's theory of gravitation is only approximately correct. Einstein's theory of general relativity provides a better model. Deviations between Newton's and Einstein's theories become observable given precise measurements over a long period of time.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;These perturbations need to be taken into account, but the basic idea still stands: One can &quot;weigh the Earth&quot; by precisely observing a satellite for a long period of time.  What's needed is a satellite specially suited to that purpose. Here it is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/7/78/LAGEOS-NASA.jpg/480px-LAGEOS-NASA.jpg&quot; alt=&quot;!LAGEOS&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is LAGEOS-1, launched in 1976. An identical twin, LAGEOS-2, was deployed in 1992. These are &lt;em&gt;extremely&lt;/em&gt; simple satellites. They have no sensors, no effectors, no communications equipment, no electronics. They are completely passive satellites. They are just solid brass balls 60 cm in diameter, covered with retroreflectors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Instead, of having the satellite make measurements, people on the ground aim lasers at the satellites. That the satellites are covered with retroreflectors means some of the laser light that hits a satellite will be reflected back to the source. Precisely timing the delay between the emission and the reception of the reflected light gives a precise measure of the distance to the satellite. Precisely measuring the frequency change between the transmitted signal and the return signal gives a precise measure of the rate at which the distance is changing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By accumulating these measurements over time, scientists can very precisely determine these satellites orbits, and from that they can &quot;weigh the Earth&quot;. The current estimate of the product $G M_E$ is $G M_E=398600.4418 \pm 0.0009 \ \text{km}^3/\text{s}^2$. (NIMA 2000). That tiny error means this is accurate to 8.6 decimal places. Almost all of the error in the mass of the Earth is going to come from the uncertainty in $G$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.michaelbeeson.com/interests/GreatMoments/Chimborazo.pdf&quot; rel=&quot;noreferrer&quot;&gt;M. Beeson, &quot;Bouguer fails to weigh the Earth&quot; (webpage)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.phys.ufl.edu/courses/phy3221/spring10/1798Cavendish.pdf&quot; rel=&quot;noreferrer&quot;&gt;H. Cavendish, &quot;Experiments to determine the Density of the Earth,&quot; &lt;em&gt;Phil. Trans. R. Soc. London,&lt;/em&gt; 88 (1798) 469-526&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikisource.org/wiki/The_Mathematical_Principles_of_Natural_Philosophy_(1846)/The_System_of_the_World&quot; rel=&quot;noreferrer&quot;&gt;I. Newton (translated by A. Motte), Principia, The System of the World (1846)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://earth-info.nga.mil/GandG/publications/tr8350.2/wgs84fin.pdf&quot; rel=&quot;noreferrer&quot;&gt;NIMA Technical Report TR8350.2, &quot;Department of Defense World Geodetic System 1984, Its Definition and Relationships With Local Geodetic Systems&quot;, Third Edition, January 2000&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://books.google.com/books?id=_2x1XZBVYhYC&quot; rel=&quot;noreferrer&quot;&gt;K. von Zittel (translated by M. Ogilvie-Gordon), &quot;History of Geology and Palæontology to the End of the Nineteenth Century,&quot; (1914)&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="-1" LastEditDate="2017-03-10T09:42:50.153" LastActivityDate="2014-05-16T23:56:40.283" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="524" PostTypeId="2" ParentId="522" CreationDate="2014-04-24T15:20:57.777" Score="20" Body="&lt;p&gt;The cause for this phenomenon is sand and silt moving down an underwater cliff as you guessed.  The geography that makes this possible is as follows.  The island of Mauritius is located on a giant plateau that was created by seafloor spreading a few million years ago.  Most of which is under 8-150 meters of water.  Where the waterfall effect occurs there is a huge drop-off which drops down thousands of meters.  Because of the islands angle when the waves beat upon the shore and displace sand, the drawing out of the waves creates, you could say, a down pulling  effect.  This motion pulls the sand and silt down the drop-off, thus creating the underwater waterfall illusion.  Because waves constantly bring sand and weathering and erosion keep making sand and silt, is not very probable that this illusion will stop for a long time, if it stop at all.  I hope this was helpful.&lt;/p&gt;&#xA;" OwnerUserId="181" LastActivityDate="2014-04-24T15:20:57.777" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="525" PostTypeId="1" CreationDate="2014-04-24T15:45:12.877" Score="14" ViewCount="240" Body="&lt;p&gt;Currently (April 2014), the fraction of the Great Lakes covered by ice is more than ten times the median amount for this time of year, the median amount being indicated by the green line in the below graph and representing the 1980-2010 time period.  The source of the graph is the &lt;a href=&quot;http://www.ec.gc.ca/glaces-ice/?lang=En&quot; rel=&quot;nofollow noreferrer&quot;&gt;Canadian Ice Service&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/sCEBD.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(in the graph, the x-axis is year, 1980-2014; the y-axis is percent ice cover 0-40%; &lt;a href=&quot;http://ice-glaces.ec.gc.ca/prods/CVCHDCTGL/20140421180000_CVCHDCTGL_0007628832.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Link to graph&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While the data in the graph are only back to 1980, looking at data from the &lt;a href=&quot;http://www.glerl.noaa.gov/data/ice/atlas/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA Atlas of Great Lakes Ice Cover&lt;/a&gt; it can be seen that the amount of ice for this time of year is unprecedented back to 1973, the earliest year in the atlas.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is, how far back would one have to go to find a year with an equal or greater amount of ice coverage on the Great Lakes at this time of the year?  Obviously the Great Lakes were glaciated thousands of years ago :), but is there any historical record of a similar ice coverage event?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;update 4/29/2014:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/kAnEO.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(x-axis is year, 1980-2014; the y-axis is percent ice cover 0-30% &lt;a href=&quot;http://ice-glaces.ec.gc.ca/prods/CVCHDCTGL/20140428180000_CVCHDCTGL_0007639788.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Link to graph&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As we close out April, the amount of ice remaining on the Great Lakes is more than 4 times greater than any other year in the 1980-2014 time period, and about 50 times the median value for this time of year.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Vast areas of Lake Superior which &lt;a href=&quot;http://iceweb1.cis.ec.gc.ca/30Atlas10/page1.xhtml?region=GL&amp;amp;lang=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;were considered by Canadian Ice Service&lt;/a&gt; as having a &lt;strong&gt;zero-probablity&lt;/strong&gt; of ice-cover at this time of year are in fact covered in very thick ice:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Y3dvO.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;update 6/2/14&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A small amount of ice still remains on Lake Superior.  This is the first time in the satellite era (1973-) that ice has been present in June.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/BOAbz.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2014-06-02T11:50:14.073" LastActivityDate="2015-02-20T17:20:22.990" Title="Ice Coverage on the Laurentian Great Lakes" Tags="|climate|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="526" PostTypeId="1" AcceptedAnswerId="528" CreationDate="2014-04-24T16:03:30.313" Score="37" ViewCount="50144" Body="&lt;p&gt;I have never understood why earth's inner core is solid.  Considering that the inner core is made of an iron-nickel alloy (melting point around 1350 C to 1600 C) and the temperature of the inner core is approximately 5430 C (about the temperature of the surface of the sun). Since Earth's core is nearly 3-4 times the melting point of iron-nickel alloys how can it possibly be solid?&lt;/p&gt;&#xA;" OwnerUserId="181" LastEditorUserId="81" LastEditDate="2014-04-25T10:03:21.593" LastActivityDate="2016-05-09T23:30:49.773" Title="Why is Earth's inner core solid?" Tags="|geophysics|core|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="527" PostTypeId="2" ParentId="526" CreationDate="2014-04-24T16:16:03.610" Score="13" Body="&lt;p&gt;You are only considering the melting point at atmospheric pressure.  Melting point depends upon pressure.  The pressure in Earth's core is about 350 GigaPascals.  It is important to study the &lt;a href=&quot;http://en.wikipedia.org/wiki/Phase_diagram&quot;&gt;phase diagram&lt;/a&gt; of the substance being considered.  A phase diagram explains what phase (solid, liquid, gas) a substance is in at various temperatures and pressures.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;http://www.gps.caltech.edu/~sue/TJA_LindhurstLabWebsite/ListPublications/Papers_pdf/Seismo_2069.pdf&quot;&gt;Phase diagram of iron, revised-core temperatures&lt;/a&gt; for detailed information.&lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2014-04-24T16:16:03.610" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="528" PostTypeId="2" ParentId="526" CreationDate="2014-04-24T16:18:32.650" Score="32" Body="&lt;p&gt;Earth's inner core is solid even though the temperature is so high because the pressure is also very high.  According to &lt;a href=&quot;http://en.wikipedia.org/wiki/Inner_core&quot; rel=&quot;noreferrer&quot;&gt;the Wikipedia article&lt;/a&gt; on the Earth's inner core, the temperature at the center is $5,700\ \text{K}$ and the pressure is estimated to be $330$ to $360\ \text{GPa}$ ($\sim3\cdot10^{6}\ \text{atm}$).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The phase diagram shown below (taken from &lt;a href=&quot;http://www.agu.org/books/gd/v031/GD031p0083/GD031p0083.pdf&quot; rel=&quot;noreferrer&quot;&gt;this paper&lt;/a&gt;) shows the liquid/solid transition, where fcc and hcp are two different crystalline forms of solid iron.  You can see clearly from the slope of the line going off toward the upper right that iron should be solid at this temperature and pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/w82eb.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="53" LastEditorUserId="53" LastEditDate="2014-04-24T16:25:01.167" LastActivityDate="2014-04-24T16:25:01.167" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="529" PostTypeId="2" ParentId="525" CreationDate="2014-04-24T16:27:37.913" Score="2" Body="&lt;p&gt;It's unprecedented for &lt;strong&gt;March&lt;/strong&gt; going back to 1973. It is not quite unprecedented; February 1979 is still the champ with 94.7% ice cover on the Great Lakes in recent history.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What about before that? Measurements were intermittent and not all that accurate. Earth observation satellites are needed to do this kind of measurement frequently and accurately. That's why the records start with 1973. (Note: Something similar happens with hurricanes records. Meteorologists didn't know how many tropical storms and hurricanes never reached shore until the advent of modern weather satellites.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Temperatures have been rising since the mid 19th century. There were eight times in the 19th century when the East River froze solid enough to walk on. Since then? None. The winters of 1815-1816 and 1816-1817 are especially good bets for even greater ice coverage on the Great Lakes. 1815 was the &quot;year without summer&quot;, thanks to the 1815 eruption of Mount Tambora. The summer of 1815 wasn't, and the winters that followed were just brutal.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2014-04-24T17:03:17.263" LastActivityDate="2014-04-24T17:03:17.263" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="530" PostTypeId="1" AcceptedAnswerId="535" CreationDate="2014-04-24T16:42:16.060" Score="31" ViewCount="39429" Body="&lt;p&gt;The Earth's inner core is solid because despite the enormous temperature in this region, there is also enormous pressure there, which in turn raises the melting point of iron and nickel to a value above the Earth's core temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now as we move out from the solid inner core, temperature drops, and pressure also decreases.  Obviously because the inner core is solid but the outer core is liquid, we must conclude that the drop in temperature vs the drop in pressure must be lower than the gradient of 16 degrees/GPa shown in the diagram below (&lt;a href=&quot;http://www.agu.org/books/gd/v031/GD031p0083/GD031p0083.pdf&quot;&gt;link to source&lt;/a&gt;), given that at the outer-core temperature has exceeded the melting point of iron/nickel, which is a function of pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, the drop in pressure must be quite significant compared to the drop in temperature as radius increases from the core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/FsLVa.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So how is it that pressure drops off fast enough relative to temperature to give rise to the liquid outer-core.  A good answer will explain how temperature drops off with radius and how pressure drops off with radius and how these compare to give rise to the liquid outer-core.&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="51" LastEditDate="2014-04-25T13:00:08.970" LastActivityDate="2020-03-31T19:57:20.453" Title="Why is Earth's outer-core liquid?" Tags="|geophysics|core|" AnswerCount="4" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="532" PostTypeId="2" ParentId="391" CreationDate="2014-04-24T17:12:08.713" Score="15" Body="&lt;p&gt;I think Azzie's answer describes the situations where gold is formed and found as &lt;a href=&quot;https://en.wikipedia.org/wiki/Lode&quot; rel=&quot;nofollow&quot;&gt;Lode deposits&lt;/a&gt;. But &lt;a href=&quot;https://en.wikipedia.org/wiki/Native_metal&quot; rel=&quot;nofollow&quot;&gt;native gold&lt;/a&gt; in lode can then be subject to weathering when it is exposed, which releases the gold into the environment as flakes, grains and nuggets. This gold is then subject to erosive and sedimentary processes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As gold is denser than most minerals it can often be concentrated by sedimentary processes as &lt;a href=&quot;https://en.wikipedia.org/wiki/Placer_deposit&quot; rel=&quot;nofollow&quot;&gt;Placer Deposits&lt;/a&gt;, where the gold is concentrated by gravity. Dense gold quickly settles out of a water column, and lighter minerals are winnowed away. These accumulations of gold can then be economically mined using &lt;a href=&quot;https://en.wikipedia.org/wiki/Placer_mining&quot; rel=&quot;nofollow&quot;&gt;Placer Mining&lt;/a&gt; techniques such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Gold_panning&quot; rel=&quot;nofollow&quot;&gt;Gold Panning&lt;/a&gt;. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Witwatersrand_basin&quot; rel=&quot;nofollow&quot;&gt;Witwatersrand Basin&lt;/a&gt; in South Africa is an important palaeo-placer deposit from which nearly 50% of all of the gold ever mined has been obtained.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alluvial placers are formed by the deposition of dense particles at a site where water velocity remains below that required to transport them further.Typical locations for gold placer deposits are on the inside bends of rivers and creeks, in hollows, at the break of slope on a stream or the base of an escarpment, waterfall or other barrier.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The vast majority of the Earth's gold and other heavy metals are locked up in the Earth’s core, being a dense material most of the gold is thought have sunk to the centre of the Earth as the core formed. Though there is 1000 times more gold in the Earth's silicate mantle than would be expected. Evidence from tungsten isotope studies indicates that most of the gold in the mantle and crust (which we can access) is derived from gold which arrived during the &lt;a href=&quot;https://en.wikipedia.org/wiki/Late_Heavy_Bombardment&quot; rel=&quot;nofollow&quot;&gt;Late Heavy Bombardment&lt;/a&gt; some 3.9 billion years ago.(&lt;a href=&quot;http://www.bbc.co.uk/news/science-environment-14827624&quot; rel=&quot;nofollow&quot;&gt;BBC Article 1&lt;/a&gt;) Which has been called the Late Veneer Hypothesis.(&lt;a href=&quot;http://www.bbc.co.uk/news/magazine-22904141&quot; rel=&quot;nofollow&quot;&gt;BBC Article 2&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Future mining of asteroids for gold and other metals has been proposed,(&lt;a href=&quot;http://uk.reuters.com/article/2013/11/21/us-space-mining-asteroids-idUKBRE9AK0JF20131121&quot; rel=&quot;nofollow&quot;&gt;Reuters Article&lt;/a&gt;) with estimates that there are up to 20,000 million tonnes of gold in the near-Earth asteroid Eros, with an estimated value of $1,000 billion (1999).(&lt;a href=&quot;http://news.bbc.co.uk/1/hi/sci/tech/401227.stm&quot; rel=&quot;nofollow&quot;&gt;BBC Article 3&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="140" LastEditorUserId="115" LastEditDate="2014-12-01T15:14:47.413" LastActivityDate="2014-12-01T15:14:47.413" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="533" PostTypeId="1" AcceptedAnswerId="536" CreationDate="2014-04-24T17:19:32.683" Score="11" ViewCount="7423" Body="&lt;p&gt;For displaying atmospheric soundings the use of Skew-T Log-P diagrams is very common. The manual &lt;a href=&quot;http://wx.erau.edu/reference/text/Tr79-006.pdf&quot;&gt;THE USE OF SKEW T, LOG P DIAGRAM IN ANALYSIS AND FORECASTING&lt;/a&gt; from the Air Weather Service explains what this diagram is and how it can be used. What tools are available to create Skew-T Log-P diagrams and how do they differ?&lt;/p&gt;&#xA;" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2016-07-25T19:15:19.797" LastActivityDate="2016-07-25T19:15:19.797" Title="How can I plot a Skew-T log-P diagram?" Tags="|meteorology|software|radiosounding|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="534" PostTypeId="2" ParentId="530" CreationDate="2014-04-24T17:23:24.843" Score="16" Body="&lt;p&gt;The pressure gradient is given by hydrostatic equilibrium.  In a solid, this may not be exactly true, but creep will make it so.  Let $p$ be the local pressure, $g$ be the local acceleration of gravity and $\rho$ the local density.  Imagine a small element of volume with area $A$ horizontal and height $\Delta h$.  Its mass is $\rho A \Delta h$ and it is attracted downward by force $g\rho \Delta h$  This has to be balanced by the pressure difference between the top and bottom, so $\frac {dp}{dh}=g\rho$.  $g$ can be determined (assuming spherical symmetry) by just counting the total mass at smaller radii.&lt;/p&gt;&#xA;" OwnerUserId="251" LastActivityDate="2014-04-24T17:23:24.843" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="535" PostTypeId="2" ParentId="530" CreationDate="2014-04-24T17:24:16.370" Score="20" Body="&lt;p&gt;First, you need a phase diagram that goes to higher pressure. The pressure at the inner/outer core boundary is over 300 GPa. The one in the question would only get us into the mantle:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/nwV8G.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.geo.arizona.edu/xtal/geos306/ironphasediagram360.jpg&quot;&gt;link to source&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A typical temperature and pressure at the outermost part of the core would be 3750K and 135GPa, which is in the liquid region of the phase diagram.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For more data on pressure and temperature as a function of depth see &lt;a href=&quot;http://www.geo.arizona.edu/xtal/geos306/fall11-13.htm&quot;&gt;this University of Arizona source&lt;/a&gt;.  All appropriate credit to Marcus Origlieri.&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="239" LastEditDate="2014-04-24T18:12:12.157" LastActivityDate="2014-04-24T18:12:12.157" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="536" PostTypeId="2" ParentId="533" CreationDate="2014-04-24T18:02:28.760" Score="16" Body="&lt;p&gt;Skew-T Log-P diagrams can be plotted in most mathmatics software.  I have seen examples in Matlab (and by proxy Octave), &lt;a href=&quot;http://www.mmm.ucar.edu/people/bryan/cm1/grads/plotskew.gs&quot; rel=&quot;noreferrer&quot;&gt;GrADS&lt;/a&gt;, &lt;a href=&quot;https://www.ncl.ucar.edu/Applications/skewt.shtml&quot; rel=&quot;noreferrer&quot;&gt;NCL&lt;/a&gt;, &lt;a href=&quot;http://cimss.ssec.wisc.edu/camex3/archive/quicklooks/skewt.pro&quot; rel=&quot;noreferrer&quot;&gt;IDL&lt;/a&gt; and I have my own code in Python that generates Skew-T plots.  There are also some programs such as &lt;a href=&quot;http://www.ral.ucar.edu/staff/knievel/callaway/4DWX_Knowledge_Base/Related_Products/Metbox/NSHARP.htm&quot; rel=&quot;noreferrer&quot;&gt;NSHARP&lt;/a&gt; and &lt;a href=&quot;http://www.wdtb.noaa.gov/tools/BUFKIT/&quot; rel=&quot;noreferrer&quot;&gt;BUFKIT&lt;/a&gt; that are more full featured.  You can also find websites that plot forecast soundings such as &lt;a href=&quot;http://www.twisterdata.com/&quot; rel=&quot;noreferrer&quot;&gt;twisterdata&lt;/a&gt; and &lt;a href=&quot;http://www.spc.noaa.gov/exper/soundings/&quot; rel=&quot;noreferrer&quot;&gt;real data soundings&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The major variances arise from the specific use case of whoever wrote the code you are using.  The most basic code will generally be able to tell you the lifting condensation level (LCL), level of free convection (LFC), equilibrium level (EL) and perhaps the 500 mb lifted index, all for a surface parcel.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The more advanced code will generally be able to calculate the above quantities not just for surface parcels, but also for the mixed layer and be able to find the most unstable parcel.  Convection oriented code will give you CAPE, storm tops and other severe weather parameters and will also tend to be able to analyze the hodograph.  BUFKIT can do analysis to identify snow growth levels and some other winter weather related quantities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the subtle differences in skew-T plotting software is how they handle the moist adiabats.  This can be modeled as a fully reversible process or a pseudo reversible process and this produces subtle temperature differences aloft on the adiabat.  There can also be differences in whether the moist adiabat only considers liquid water and vapor, or if ice process are included in the latent heat release.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is an example of what my Python code produces:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Cxbk5.png&quot; alt=&quot;Skew-T&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Var          SFC            ML              MU&#xA;CAPE  J/kg   1877           1877            2415&#xA;CIN   J/kg   46.9           46.9            0.4&#xA;LI_max       -9.5           -9.5            -11.3&#xA;LI_500       -7.3           -7.3            -8.4&#xA;LI_30        -4.8           -4.8            -6.4&#xA;TOPS  m      14800          14800           15400&#xA;LCL   mb (m) 892 (1000)     892 (1000)      862 (1292)&#xA;LFC   mb (m) 831 (1604)     831 (1604)      857 (1343)&#xA;PRS   mb     1000           1000            871&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-04-24T18:02:28.760" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="537" PostTypeId="2" ParentId="441" CreationDate="2014-04-24T18:15:32.950" Score="2" Body="&lt;p&gt;My first grid generation was using SMS (&lt;a href=&quot;http://www.aquaveo.com/software/sms-surface-water-modeling-system-introduction&quot; rel=&quot;nofollow&quot;&gt;http://www.aquaveo.com/software/sms-surface-water-modeling-system-introduction&lt;/a&gt;). That software is proprietary and it used to be cumbersome to get it to do what you needed sometimes. It also provides metrics for grid quality.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The tool that I am more familiar with is BatTri. It was developed by Ata Bilgili and Keston Smith and is a graphical Matlab interface to the C language two-dimensional quality grid generator Triangle developed by Jonathan Richard Shewchuk. They explain the code in &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0098300405001950&quot; rel=&quot;nofollow&quot;&gt;http://www.sciencedirect.com/science/article/pii/S0098300405001950&lt;/a&gt;. They include several quality checks that I have found quite useful.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have just found this website (&lt;a href=&quot;http://www.robertschneiders.de/meshgeneration/software.html&quot; rel=&quot;nofollow&quot;&gt;http://www.robertschneiders.de/meshgeneration/software.html&lt;/a&gt;) that lists a lot of mesh generation software. Most of them I have never heard of or know anything about. &lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-04-24T18:15:32.950" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="538" PostTypeId="2" ParentId="196" CreationDate="2014-04-24T18:47:02.920" Score="5" Body="&lt;p&gt;One issue here is whether El Niño (ENSO) is chaotic in nature. There is a fair amount of literature on the chaotic and deterministic nature of ENSO (e.g., &lt;a href=&quot;https://www.sciencemag.org/content/264/5155/72.abstract&quot; rel=&quot;noreferrer&quot;&gt;https://www.sciencemag.org/content/264/5155/72.abstract&lt;/a&gt;, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/97GL53639/full&quot; rel=&quot;noreferrer&quot;&gt;http://onlinelibrary.wiley.com/doi/10.1029/97GL53639/full&lt;/a&gt;). Under the chaotic assumption, the posted question might not have a clear answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then there is the fact that ENSO affects the atmospheric-oceanic energy budget. If too much energy is available, then El Niño might happen, but whether it is stronger is unclear. &lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-04-24T18:47:02.920" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="539" PostTypeId="5" CreationDate="2014-04-24T19:42:10.110" Score="0" Body="&lt;p&gt;For questions about the Earth's core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seismic refraction data has shown that the Earth has a central core surrounded by a &lt;a href=&quot;/questions/tagged/mantle&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged &amp;#39;mantle&amp;#39;&quot; rel=&quot;tag&quot;&gt;mantle&lt;/a&gt;, which in turn is surrounded by the relatively thin &lt;a href=&quot;/questions/tagged/crust&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged &amp;#39;crust&amp;#39;&quot; rel=&quot;tag&quot;&gt;crust&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Following the chonditic model of the Earth and other evidence (eg. mass distribution, active magnetic field), the core is primarily composed of iron and nickel. The inner core is ~1220 km diameter and solid due to high pressure. This is surrounded by the liquid outer core which is ~2260 km thick. The solid:liquid boundary produces a strong seismic reflector and S waves do not pass through the outer core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The outer core is actively convecting and is believed to act as a 'self exciting dynamo' which produces the Earth's active magnetic field.&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorUserId="44" LastEditDate="2014-06-14T17:20:31.130" LastActivityDate="2014-06-14T17:20:31.130" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="540" PostTypeId="4" CreationDate="2014-04-24T19:42:10.110" Score="0" Body="For questions about the Earth's core. The center of the Earth is primarily iron-nickel." OwnerUserId="44" LastEditorUserId="44" LastEditDate="2014-06-14T17:19:21.620" LastActivityDate="2014-06-14T17:19:21.620" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="541" PostTypeId="1" AcceptedAnswerId="542" CreationDate="2014-04-24T20:16:42.790" Score="23" ViewCount="5205" Body="&lt;p&gt;Wind is (according to &lt;a href=&quot;http://en.wikipedia.org/wiki/Wind&quot;&gt;Wikipedia&lt;/a&gt;) the flow of gases on a large scale.&lt;br/&gt;On the surface of the Earth, wind consists of the bulk movement of air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What forces would cause such a mass movement of air?&lt;/p&gt;&#xA;" OwnerUserId="116" LastEditorUserId="64" LastEditDate="2015-05-04T18:36:49.537" LastActivityDate="2023-07-17T12:58:27.390" Title="Where does wind come from?" Tags="|meteorology|atmosphere|wind|air-currents|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="542" PostTypeId="2" ParentId="541" CreationDate="2014-04-24T20:25:24.663" Score="20" Body="&lt;p&gt;Wind is caused by pressure differences.  Think of a balloon full of air; poke a hole in it and the air comes out.  Why?  Because the pressure in the balloon is higher than outside, and so to regain equal pressure, mass moves and that is the wind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a bit more to this in the atmosphere as the Earth rotates and near the surface friction also plays a role.  The equation of motion is the Navier-Stokes and in vector form in Cartesian space is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\dfrac{\partial\mathbf u}{\partial t} = - \mathbf u \cdot \nabla \mathbf u  -\dfrac{1}{\rho}\nabla p-2 \mathbf \Omega \times \mathbf u + \mathbf g + \mathbf F$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this equation, $\mathbf u$ is the vector wind, $(\mathbf u \cdot \nabla)$ is the advection operator, $\rho$ is density, $\mathbf \Omega$ is the vector rotation of the Earth, $\mathbf g$ is effective gravity and $\mathbf F$ is friction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The LHS is the time rate of change of the wind at a point in space (as opposed to following the parcel).  The RHS represent a number of factors that produce a change in the wind.  From left to right: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Advection of momentum (non-linear)&lt;/li&gt;&#xA;&lt;li&gt;Pressure gradient force (this is wind blowing from high to low pressure)&lt;/li&gt;&#xA;&lt;li&gt;Coriolis force (this turns wind to the right in the NH and left in the SH and causes the wind to flow parallel to isobars)&lt;/li&gt;&#xA;&lt;li&gt;gravity (provides hydrostatic balance with the PGF in the vertical)&lt;/li&gt;&#xA;&lt;li&gt;Friction (in the boundary layer you may see this as $\nu\nabla^2\mathbf u$)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;For large scale synoptic flow above the surface, this is often simplified as a balanced flow called &lt;em&gt;geostrophic balance&lt;/em&gt;.  This a steady flow with a balance between the PGF and Coriolis force in the horizontal and hydrostatic balance in the vertical.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ \dfrac{1}{\rho}\nabla p = 2 \mathbf \Omega \times \mathbf u $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which can also be written as &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$u_g = -\dfrac{1}{\rho f}\dfrac{\partial p}{\partial y}$$&#xA;$$v_g =  \dfrac{1}{\rho f}\dfrac{\partial p}{\partial x}$$&#xA;$$\dfrac{\partial p}{\partial z} = -\rho g$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In these equations, $u_g$ is the geostrophic wind in the east/west direction and $v_g$ is the geostrophic wind in the north/south direction and $f$ is the Coriolis parameter ($f = 2\Omega\sin\phi$, where $\phi$ is lattitude).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For this idealized geostrophic and hydrostatic balance, there is no vertical motion and all horizontal flow is parallel to isobars, flowing clockwise (counter-clockwise) around high pressure in the NH (SH) and flowing counter-clockwise (clockwise) around low pressure in the NH (SH).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For curved flow, we can consider another balance, the &lt;em&gt;gradient wind balance&lt;/em&gt; that allows acceleration of the flow though centrifugal forces.  This can be written as (where $n$ is in the cross-wind direction):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ \dfrac{V^2}{R_t} = -fV - \dfrac{1}{\rho}\dfrac{\partial p}{\partial n} $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where $R_t$ is the radius of curvature in the flow. In the limit of $R_t \rightarrow \infty$ the acceleration term vanishes and this becomes geostrophic flow.  The consequence of this balance is that wind will flow slower than geostrophic balance around a low pressure center, this is said to be &lt;em&gt;subgeostrophic&lt;/em&gt;.  Around a high pressure center we have &lt;em&gt;supergeostrophic&lt;/em&gt; flow, or faster than geostrophic.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;You may have noticed the wind balances above are non-divergent and lack vertical flow.  This makes for boring weather, and does not hold near the ground or where vertical motion is large.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We term the deviation from geostrophic flow the &lt;em&gt;ageostrophic&lt;/em&gt; wind and this accounts for friction.  This results in wind converging toward low pressure and diverging from high pressure. &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Another flow is the &lt;em&gt;isallobaric&lt;/em&gt; wind, and this is wind that blows from pressure rises toward pressure falls.  A place you will normally see this wind is just as a cold front passes and the pressure rises behind the front and falls in front of it.  This enhances the cross frontal wind and helps produce the often strong, gusty winds after a cold front passes.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2014-04-24T21:36:23.657" LastActivityDate="2014-04-24T21:36:23.657" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="543" PostTypeId="2" ParentId="29" CreationDate="2014-04-24T20:52:17.297" Score="10" Body="&lt;p&gt;The heat content of a substance is known as &lt;a href=&quot;http://en.wikipedia.org/wiki/Enthalpy&quot; rel=&quot;nofollow&quot;&gt;enthalpy&lt;/a&gt;.  The international convention used for the &lt;a href=&quot;http://www.teos-10.org/&quot; rel=&quot;nofollow&quot;&gt;Thermodynamic Equation of Sea Water&lt;/a&gt; is maintained by the Joint Committee on the Properties of Seawater. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Equations for calculating the thermodynamic variables of sea water, humid air and other substances are set forth in &lt;a href=&quot;http://www.teos-10.org/pubs/SIA_Paper_1.pdf&quot; rel=&quot;nofollow&quot;&gt;&lt;strong&gt;the Numerical implementation and oceanographic application of the thermodynamic potentials of liquid water, water vapour, ice, seawater and humid air – Part 1: Background and equations&lt;/strong&gt;&lt;/a&gt; by R. Feistel, D. G. Wright,†, D. R. Jackett, K. Miyagawa, J. H. Reissmann, W. Wagner, U. Overhoff, C. Guder&#xA;,A. Feistel, and G. M. Marion. &lt;em&gt;Enthalpy of sea water is discussed in section 4.3.&lt;/em&gt;   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One would need temperature, pressure and salinity information for each point in the ocean, and integrate specific enthalpy over the entire volume of the ocean. &lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="543" LastEditDate="2015-12-12T12:24:54.263" LastActivityDate="2015-12-12T12:24:54.263" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="544" PostTypeId="1" AcceptedAnswerId="545" CreationDate="2014-04-24T21:10:37.733" Score="14" ViewCount="1850" Body="&lt;p&gt;I would like to calculate the force of an underwater current on a meter by meter plate (or any other unit that you may use to represent it) that is standing in front of the current.&#xA;How do I calculate it? What parameters do I need?&lt;/p&gt;&#xA;" OwnerUserId="261" LastEditorUserId="192" LastEditDate="2016-05-28T16:21:43.443" LastActivityDate="2016-05-28T16:21:43.443" Title="What is the force imposed by underwater currents?" Tags="|models|ocean-currents|numerical-modelling|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="545" PostTypeId="2" ParentId="544" CreationDate="2014-04-24T21:47:48.730" Score="13" Body="&lt;p&gt;You are looking for the drag force imposed by the fluid flow on an object:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$F = \dfrac{1}{2} \rho v^{2} C_D A$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\rho$ is the density of the fluid, $v$ is the speed of the flow, $C_D$ is the &lt;a href=&quot;http://en.wikipedia.org/wiki/Drag_coefficient&quot;&gt;drag coefficient&lt;/a&gt; depending on the shape of the object, and $A$ is the surface area normal to the fluid flow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's plug in some characteristic numbers for scaling. For a current of 1 m s$^{-1}$, fluid density of 1000 kg m$^{-3}$, drag coefficient of 1, surface area of 1 m$^2$, the force imposed by the fluid on the object, according to the equation above, would be 500 N.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that this equation is valid only for high $Re$ flows that produce turbulence in the wake of the object. The drag coefficient is estimated empirically and takes into account both skin and form drag of the object.&lt;/p&gt;&#xA;" OwnerUserId="192" LastActivityDate="2014-04-24T21:47:48.730" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="546" PostTypeId="1" AcceptedAnswerId="574" CreationDate="2014-04-24T23:10:22.333" Score="19" ViewCount="304" Body="&lt;p&gt;With global climate change, is it possible that tropical cyclones (as seen in the Atlantic basin for example) are going to form and be sustained in regions where they previously did not, for example near Europe?&lt;/p&gt;&#xA;" OwnerUserId="68" LastEditorUserId="192" LastEditDate="2014-04-26T19:31:50.630" LastActivityDate="2014-05-15T13:41:24.783" Title="Will tropical cyclones form and be sustained in areas they previously were not due to global climate change?" Tags="|meteorology|global-warming|tropical-cyclone|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="547" PostTypeId="1" CreationDate="2014-04-25T01:52:50.240" Score="9" ViewCount="955" Body="&lt;p&gt;Natural catastrophic events such as hurricanes, earthquakes, volcanic eruptions and meteor impacts releases vast amount of energy. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the most powerful single event of such nature ever recorded in human history on the planet Earth? And as a measure of energy release, how many atomic bombs or megatons of TNT is that equivalent to? What kind of event releases most energy? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How would the most powerful events compare with modern day natural disasters, to give some sense of perspective. &lt;/p&gt;&#xA;" OwnerUserId="263" LastEditorUserId="2536" LastEditDate="2015-05-05T10:02:00.353" LastActivityDate="2015-05-06T07:22:30.327" Title="What is the most powerful natural catastrophic event on record?" Tags="|volcanology|earthquakes|tropical-cyclone|meteorite|storms|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="548" PostTypeId="2" ParentId="4" CreationDate="2014-04-25T02:38:44.623" Score="4" Body="&lt;p&gt;It is true that water is not the only variable constituent of the atmosphere, but it is capable of large variations (0-5%+) that I'm not sure other trace constituents are capable of outside of plumes from smokestacks / cars / factories / etc.  A virtual temperature for other gases would only be meaningful if their variability imparts a significant change in mass in a parcel such that it becomes important for buoyancy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That being said, you could easily derive such a virtual temperature, as the virtual temperature is just a proxy for density changes and we can easily calculate this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For each constituent gas, you can use the ideal gas law as&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$p_i = \rho_i R_i T$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;such that each density of gas $i$ is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\rho_i = \dfrac{p_i}{R_i T}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and then sum these with dry air ($p_d$)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\rho = \dfrac{p-\sum p_i}{R_d T} + {\large\sum} \dfrac{p_i}{R_i T} $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and then solving for $p$ in terms of $\rho$, $R_d$ and collecting the rest of the terms into a variable and calling it $T_v$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This process could be used to generically define a virtual temperature for any number of trace gases (single or multiple) as long as you know their mixing ratios with dry air.  I'm not aware of anyone using (on Earth) a virtual temp for anything other than water vapor and suspended hydrometeors (e.g. density potential temperature, $\theta_\rho$) but that certainly doesn't mean no one is.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-04-25T02:38:44.623" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="550" PostTypeId="2" ParentId="526" CreationDate="2014-04-25T04:53:49.493" Score="22" Body="&lt;p&gt;In addition to the answers below and my comment above, I believe the following phase diagram, from DavePhd's answer &lt;a href=&quot;https://earthscience.stackexchange.com/questions/530/why-is-earths-outer-core-liquid/535#535&quot;&gt;here&lt;/a&gt;, sourced from &lt;a href=&quot;http://www.geo.arizona.edu/xtal/geos306/ironphasediagram360.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, is more appropriate for the pressure levels near the Earth's core of about 330 to 360GPa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can see from the image that for pressures between 330 and 360GPa, the melting temperature ranges from about 6200 K to 6600 K, which is much higher than Earth's inner core temperature of about 5700 K.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/iIt52.jpg&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-04-25T04:53:49.493" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="551" PostTypeId="1" AcceptedAnswerId="2594" CreationDate="2014-04-25T05:40:15.343" Score="13" ViewCount="1045" Body="&lt;p&gt;Paleosalinity is measured by chloricity of pore fluids (&lt;a href=&quot;http://schraglab.unix.fas.harvard.edu/publications/CV49.pdf&quot;&gt;Adkins 2002&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Current data are provided by &lt;a href=&quot;https://en.wikipedia.org/wiki/CORA_dataset&quot;&gt;the CORA dataset&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to answers to the main question, there are a few more points I'd like to know:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;How can one forecast ocean salinity?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;What is the relationship between forecast errors and forecast horizon?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Are there any existing global salinity forecasts?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;What are the sources of uncertainty in forecasting salinity 100 years ahead?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="269" LastEditorUserId="111" LastEditDate="2017-11-30T16:54:35.243" LastActivityDate="2017-11-30T16:54:35.243" Title="Is it possible to forecast ocean salinity 100 years into the future?" Tags="|climate-change|oceanography|salinity|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="552" PostTypeId="2" ParentId="319" CreationDate="2014-04-25T11:56:55.300" Score="11" Body="&lt;p&gt;A few elements to complement @Siv answer, and some alternatives hypotheses:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Originally the idea was that the Fe&lt;sup&gt;2+&lt;/sup&gt; oxidation into Fe&lt;sup&gt;3+&lt;/sup&gt; that lead to the formation of the BIF (&quot;banded iron formations&quot;) was an indirect consequence of the increased atmospheric p&lt;sub&gt;O&lt;sub&gt;2&lt;/sub&gt;&lt;/sub&gt; caused by the photosynthetic activity of, then freshly appeared, cyanobacteria (see e. g. &lt;strong&gt;Cloud 1973&lt;/strong&gt;  which, along with &lt;strong&gt;Cloud 1968&lt;/strong&gt;, are i think the first occurrence in the literature of such an idea). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Later, the idea that the cause of the iron oxidation was linked to a specific metabolic reaction involved in &lt;em&gt;anoxygenic&lt;/em&gt; photosynthesis (i. e. a different way of fixing CO&lt;sub&gt;2&lt;/sub&gt; that does not create O&lt;sub&gt;2&lt;/sub&gt;) in bacteria was also introduced (&lt;strong&gt;Hartman 1984; Konhauser et al. 2005&lt;/strong&gt;).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another possibility invoked by &lt;strong&gt;Holm 1989&lt;/strong&gt; is the active oxidation of Fe&lt;sup&gt;2+&lt;/sup&gt; by &quot;chemolithoautotrophic&quot; bacteria (using it directly as energy source).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, the only (as far as I can see) non-bacterial hypothesis on the BIF formation is that of photo-oxidation (&lt;strong&gt;Braterman et al. 1983&lt;/strong&gt;): the oxidation and precipitation of Fe&lt;sup&gt;2+&lt;/sup&gt; in Fe&lt;sup&gt;3+&lt;/sup&gt; being indeed possible without oxygen, in strongly acid conditions with a little help from UV photons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;&lt;strong&gt;References:&lt;/strong&gt;&lt;br&gt;&#xA;Braterman P. S., Cairns-Smith A. G., Sloper R. W., 1983. &lt;a href=&quot;http://dx.doi.org/10.1038/303163a0&quot;&gt;Photo-oxidation of hydrated Fe&lt;sup&gt;2+&lt;/sup&gt; – significance for banded iron formations&lt;/a&gt;. Nature, 303: 163-164.&lt;br&gt;&#xA;Cloud P., 1968. &lt;a href=&quot;http://dx.doi.org/10.1126/science.160.3829.729&quot;&gt;Atmospheric and hydrospheric evolution on the primitive earth&lt;/a&gt;. Science, 160, 729–736.&lt;br&gt;&#xA;Cloud P., 1973. &lt;a href=&quot;http://dx.doi.org/10.2113/gsecongeo.68.7.1135&quot;&gt;Paleoecological Significance of the Banded Iron-Formation&lt;/a&gt;. Economic Geology and the Bulletin of the Society of Economic Geologists, 68: 1135-1143.&lt;br&gt;&#xA;Hartman H., 1984. The evolution of photosynthesis and microbial mats: A speculation on the banded iron formations. In Y. Cohen et al. (Eds), Microbial  Mats: Stromatolites, Alan Liss Inc. (New York): 449–453.&lt;br&gt;&#xA;Holm N. G., 1989. &lt;a href=&quot;http://dx.doi.org/10.1016/0009-2541(89)90013-2&quot;&gt;The &lt;sup&gt;13&lt;/sup&gt;C/&lt;sup&gt;12&lt;/sup&gt;C ratios of siderite and organic matter of a modern metalliferous hydrothermal sediment and their implications for banded iron formations&lt;/a&gt;. Chemical Geology, 77: 41-45.&lt;br&gt;&#xA;Konhauser K. O., Newman D. K., Kappler A., 2005. &lt;a href=&quot;http://dx.doi.org/10.1111/j.1472-4669.2005.00055.x&quot;&gt;The potential signiﬁcance of microbial Fe(III) reduction during deposition of Precambrian banded iron formations&lt;/a&gt;. Geobiology, 3, 167–177.&lt;br&gt;&#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-08-15T06:50:47.857" LastActivityDate="2014-08-15T06:50:47.857" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="553" PostTypeId="5" CreationDate="2014-04-25T12:08:05.303" Score="0" Body="&lt;p&gt;Geobiology is the study of the link between life and its chemical and physical environment. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In pratice, as bacteria do not fossilize directly, extinct bacteria are studied thanks to their chemical impact on their geological environment (concretions, oxidations, etc.); therefore bacteria are typically studied in the context of geobiology and not paleontology.&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-04-25T13:05:04.860" LastActivityDate="2014-04-25T13:05:04.860" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="554" PostTypeId="4" CreationDate="2014-04-25T12:08:05.303" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-25T12:08:05.303" LastActivityDate="2014-04-25T12:08:05.303" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="555" PostTypeId="1" AcceptedAnswerId="556" CreationDate="2014-04-25T12:59:14.950" Score="4" ViewCount="10063" Body="&lt;p&gt;According to &lt;a href=&quot;http://en.wikipedia.org/wiki/Mantle_%28geology%29&quot; rel=&quot;nofollow&quot;&gt;Wikipedia&lt;/a&gt; the earth's mantle is approximately 2900 km (1,800 miles) thick.&lt;br/&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How is it possible to achieve such measurements?&lt;br/&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously we haven't sent anything down that far to check.&lt;/p&gt;&#xA;" OwnerUserId="116" LastEditorUserId="23" LastEditDate="2014-04-26T19:27:44.307" LastActivityDate="2014-04-26T19:27:44.307" Title="How can we measure the thickness of the Earth's mantle?" Tags="|geophysics|measurements|" AnswerCount="2" CommentCount="6" FavoriteCount="0" ClosedDate="2014-04-30T14:22:23.473" ContentLicense="CC BY-SA 3.0" />
  <row Id="556" PostTypeId="2" ParentId="555" CreationDate="2014-04-25T13:20:08.377" Score="8" Body="&lt;p&gt;You are right...noone ever was able to make a borehole that deep. The two deepest boreholes are about. 12.300 m (40.400 ft) - those are the Kola Superdeep Borehole in Russia and the Al Shaheen oil well in Qatar.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So how do we measure the thickness of our subsurface? Think of the earth as an onion with different layers. Each of those layers (lithosphere, asthenosphere, mesospheric mantle, outer core, inner core) contain different mechanical (and chemical) properties. Due to this it is possible to infer indirectly the depth of each layer by using the travel time of refracted/reflected seismic waves (those come from earthquakes).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As mentioned before, each layer contains different mechanical properties, thus making the seismic velocity different in each layer. So on the border of each layer, those changes cause refraction or reflection if large increases in seismic velocity are involved.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Conclusion: no direct measurements possible, only indirectly derived measurements by the speed of travel from seismic waves.&lt;/p&gt;&#xA;" OwnerUserId="278" LastActivityDate="2014-04-25T13:20:08.377" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="557" PostTypeId="1" AcceptedAnswerId="938" CreationDate="2014-04-25T13:45:24.823" Score="9" ViewCount="442" Body="&lt;p&gt;Answers from these two questions: &#xA;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/517/how-can-we-guess-the-size-of-the-earths-inner-coreand-what-its-made-of&quot;&gt;How can we guess the size of the earths inner core?&lt;/a&gt; &lt;br/&gt;&#xA;&amp;amp; &#xA;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/555/how-can-we-measure-the-thickness-of-the-earths-mantle&quot;&gt;How can we measure the thickness of the earths mantle?&lt;/a&gt; &#xA;use seismic waves as the &lt;br/&gt;method for detirmining size and thickness of sections in the earth.&lt;br/&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this the only way of measuring the inner sections of the earth?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Bonus Points:&lt;/strong&gt; Where did the idea of using seismic waves to measure earth's layers start?&lt;/p&gt;&#xA;" OwnerUserId="116" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-05-15T20:00:21.573" Title="Is seismology really the only way to measure the thickness of Earth's layers?" Tags="|measurements|seismology|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="558" PostTypeId="2" ParentId="547" CreationDate="2014-04-25T14:35:39.497" Score="3" Body="&lt;p&gt;hard to impossible to tell. In recorded history it was for sure one of those massive volcanic eruptions from Krakatoa, Yellowstone or Tambora. But in earth's history there were some impacts from meteorites or commets that must have been a lot more powerfull in terms of released energy than any volcanic erruption. My guess is the Vredefort crater in South Africa (largest verified impact crater on Earth with a diameter of 300 km) or the Chicxulub crater in Mexico that is said to have triggered the mass extinction of the dinosaurs.&lt;/p&gt;&#xA;" OwnerUserId="278" LastActivityDate="2014-04-25T14:35:39.497" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="559" PostTypeId="2" ParentId="557" CreationDate="2014-04-25T14:41:29.740" Score="6" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Robert_Mallet&quot;&gt;Robert Mallet&lt;/a&gt; is sometimes referred to as the &quot;father of seismology.&quot; He was helped (around 1850) by the newly created science of photography, which enabled him to create seismic &quot;maps&quot; of the earth, at different depths.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;He has started life as an iron engineer/manufacturer, but turned his talents to seismology after a number of devastating earthquakes in Europe. His earlier work with iron gave him a background in the use of explosives to &quot;open up&quot; the earth at critical points.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Paleoseismology&quot;&gt;Paleoseismology&lt;/a&gt; is a related field that relies on paleontology to form estimates of various properties of the earth.&lt;/p&gt;&#xA;" OwnerUserId="42" LastActivityDate="2014-04-25T14:41:29.740" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="560" PostTypeId="1" AcceptedAnswerId="781" CreationDate="2014-04-25T16:51:32.157" Score="19" ViewCount="352" Body="&lt;p&gt;At the 2011 AGU Fall meeting, this &lt;a href=&quot;http://adsabs.harvard.edu/abs/2011AGUFM.U53E..06W&quot;&gt;poster&lt;/a&gt; claimed that the water erosion from Taiwan's wettest storms could prematurely trigger large magnitude earthquakes , $ M \ge 6.0 $. If this was true, this discovery would be incredibly important for not only our understand of earthquake mechanics but also hazard prevention. Could this theory really be correct?&lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-05-05T14:18:55.523" Title="Can large (and wet) storms really trigger large magnitude Earthquakes?" Tags="|geophysics|climate|earthquakes|storms|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="561" PostTypeId="2" ParentId="555" CreationDate="2014-04-25T17:00:21.993" Score="4" Body="&lt;p&gt;Very important is that the outer core being liquid (and mantle solid), shear waves from earthquakes cannot travel through the outer core. Along with refraction and reflection of &lt;em&gt;P&lt;/em&gt;-waves at the core-mantle boundary, this &lt;em&gt;S&lt;/em&gt;-wave shadow makes it possible to figure out how far down the boundary is.&lt;/p&gt;&#xA;" OwnerUserId="280" LastActivityDate="2014-04-25T17:00:21.993" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="562" PostTypeId="1" AcceptedAnswerId="577" CreationDate="2014-04-25T17:00:36.133" Score="30" ViewCount="45155" Body="&lt;p&gt;This question has puzzled me for a while. I know that earth's mantle is made of different minerals, metals and rocks etc. and that has always made complete sense to me.  But why is the inner core made of an iron-nickel alloy?  The only reasons that I could come up with (they are kind of crazy) is that:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A. The iron-nickel alloy that composes the inner core is heavier than other elements in the mantle and outer core, causing it to sink to the center of earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;B. Since both iron and nickel and attracted to magnets earth's magnetic field drew the to metals into the inner core mixing them into the alloy. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;C. Earth started as a giant asteroid composed of an iron-nickel alloy (which many are), and other materials from space built upon it causing earth to have an iron-nickel core (I told you they were crazy!). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But these explanations don't really make much sense to me.&lt;/p&gt;&#xA;" OwnerUserId="181" LastEditorDisplayName="user12525" LastEditDate="2019-04-17T10:23:19.973" LastActivityDate="2019-08-13T17:42:11.860" Title="Why is Earth's inner core made of an iron-nickel alloy?" Tags="|geology|geophysics|earth-history|core|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="563" PostTypeId="1" AcceptedAnswerId="653" CreationDate="2014-04-25T17:29:49.730" Score="12" ViewCount="409" Body="&lt;p&gt;Although I basically understand, that how the Himalayas formed, it has always confused me how did the vast high Tibetian Plateau came into existence behind it? And what would be its future, is it expected to remain as such for a long time?&lt;/p&gt;&#xA;" OwnerUserId="276" LastEditorUserId="140" LastEditDate="2014-05-01T01:01:24.330" LastActivityDate="2014-05-01T01:01:24.330" Title="What is the current theory about the formation of Tibet?" Tags="|tibetan-plateau|orogeny|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="564" PostTypeId="1" AcceptedAnswerId="567" CreationDate="2014-04-25T20:44:17.910" Score="11" ViewCount="162" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Magnetic_survey_%28archaeology%29&quot; rel=&quot;noreferrer&quot;&gt;Magnetometry&lt;/a&gt; is used to find archaeological features such as stone walls or ancient hearth. But it usually cannot be used for archaeological prospection in areas where the bedrock is strongly magnetic. Let's assume basalt - it is quite common near the town I come from. With an average &lt;a href=&quot;http://en.wikipedia.org/wiki/Magnetometers#Caesium_vapour_magnetometer&quot; rel=&quot;noreferrer&quot;&gt;cesium vapour magnetometer&lt;/a&gt;, how thick must be the soil so that I could find remains of highly magnetic features like remains of a burnt &lt;a href=&quot;http://en.wikipedia.org/wiki/Wattle_and_daub&quot; rel=&quot;noreferrer&quot;&gt;wattle-and-daub&lt;/a&gt; house or an iron depot? And if operating near a fault between magnetic and non-magnetic rock, how far from the magnetic rock can I find weakly magnetic situations like disturbed soil?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: I expect approximate answer. An answer I would expect could start: &quot;Iron is more magnetic than basalt, so several kilograms of iron (or iron rust) could be found even less than a meter above the bedrock under condidtions X, several meters otherwise. Very small iron items and piles of burnt soil would usually need several tens of meters...&quot; I just guess all the facts, I don't know, I'm just an archaeologist with no background i geophysics. The aim of this edit is to emphasize that I don't need exact numbers, but I need an idea which numbers might be exact and which are likely to be completely wrong.&lt;/p&gt;&#xA;" OwnerUserId="101" LastEditorUserId="101" LastEditDate="2014-04-28T11:20:03.233" LastActivityDate="2016-03-29T17:44:50.387" Title="How far from basalt bedrock can magnetometic survey find archaeological features?" Tags="|geophysics|archaeology|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="565" PostTypeId="1" AcceptedAnswerId="782" CreationDate="2014-04-25T20:57:54.550" Score="15" ViewCount="3357" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Organism&quot;&gt;According to Wikipedia&lt;/a&gt;, &quot;all known types of organism are capable of some degree of response to stimuli, reproduction, growth and development and self-regulation via homeostasis.&quot; Further, watching a video like the &quot;&lt;a href=&quot;http://www.youtube.com/watch?v=kSNbLYHRrU8&quot;&gt;Earth Breathes as Seasons Change&lt;/a&gt;&quot; (&lt;a href=&quot;http://www.nasa.gov/vision/earth/features/blue_marble.html&quot;&gt;which is from NASA&lt;/a&gt;) - superficially gives the sense that the &quot;Earth is alive&quot; so to speak. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is Earth an organism?&lt;/strong&gt; Since there is no unequivocal definition of life, the current understanding is descriptive. To define Earth as an organism, your answer most show either via observed phenomena or theoretically observable phenomena that Earth exhibits all or most of the following traits: &lt;a href=&quot;https://en.wikipedia.org/wiki/Life#Biology&quot;&gt;Homeostasis, Organization, Metabolism, Growth, Adaptation, Response to stimuli, and Reproduction&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="140" LastEditDate="2014-05-06T13:47:08.077" LastActivityDate="2021-02-25T19:00:45.723" Title="Is Earth an organism?" Tags="|earth-history|planetary-science|earth-observation|" AnswerCount="5" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="566" PostTypeId="2" ParentId="562" CreationDate="2014-04-25T22:06:14.073" Score="1" Body="&lt;p&gt;From what I found after doing a little research on this question, your answer C is the most accurate explanation.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Scientists believe that the overall chemical composition of the Earth is very similar to a kind of meteorite called chondrites, which formed at the same time the Earth was formed. We know a lot about the composition of the Earths crust and mantle, because we can observe those rocks that have been brought to the surface by geologic processes. By comparing the composition of rocks from the Earths crust and mantle to the composition of chondrites, we can see what elements are missing, and therefore must be found in the core. Theories about how Earths magnetic field is formed, as well as experiments done at high temperature and pressures give clues as to the actual composition of the Earths core. Based on all these theories and observations, scientists know that the Earths core is mostly iron with some nickel and lighter elements such as oxygen or sulfur.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Reference: &lt;a href=&quot;http://scienceline.ucsb.edu/getkey.php?key=2618&quot; rel=&quot;nofollow&quot;&gt;http://scienceline.ucsb.edu/getkey.php?key=2618&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="206" LastEditorUserId="20" LastEditDate="2014-05-01T21:55:42.423" LastActivityDate="2014-05-01T21:55:42.423" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="567" PostTypeId="2" ParentId="564" CreationDate="2014-04-25T22:16:33.613" Score="5" Body="&lt;p&gt;You can get a good idea of the magnitude and wavelengths of typical archaeological magnetic anomalies with a literature search. For instance this page shows a magnetic map of fire hearths &lt;a href=&quot;http://en.wikipedia.org/wiki/Magnetic_survey_%28archaeology%29&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/Magnetic_survey_(archaeology)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geology is a lot more complicated though and there are many variables that might affect the background magnetic signature. It doesn't matter how much you study up on basalt rock properties you still won't know enough about the rocks in your project area to predict the outcome of a survey. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your best hope is to use prior experience from other surveys close to your project area. If a survey worked in one farmer's field then it will probably work in the adjacent field as well. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If no one has collected any magnetic data close to your project area then go ask the geophysicists if they will do a test line or two. If it works great, if not then try something else like magnetic gradiometry, resistivity or ground probing radar. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sorry I can't give you a definitive answer to your question. I understand what you are asking but geology is just too complex to give you a useful rule of thumb. &lt;/p&gt;&#xA;" OwnerUserId="8" LastEditorUserId="8" LastEditDate="2014-04-30T18:50:23.123" LastActivityDate="2014-04-30T18:50:23.123" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="568" PostTypeId="2" ParentId="352" CreationDate="2014-04-25T22:58:17.203" Score="7" Body="&lt;p&gt;To supplement the current and very good answers , we can look at a seismogram:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/cMYSj.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;from (&lt;a href=&quot;http://www.bgs.ac.uk/discoveringGeology/hazards/earthquakes/images/dia_seismogram.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.bgs.ac.uk/discoveringGeology/hazards/earthquakes/images/dia_seismogram.jpg&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, we know that P-waves(compressional) will generally arrives before S-waves(shear). Also, in general, S-waves will arrive before the much stronger in response body waves. To distinguish which waves are which, we use a three directional seismometer, which will record three different seismograms: Radial, North-South, and East-West. Notice that all these directions are perpendicular to each other.  The characteristic wave motion of the specific wave you are analyzing  will cause stronger or weaker perturbations on each of the different directional seismographs depending on how the wave arrives. For example, if a shear wave arrives directly beneath a the seismometer, because of the wave motion, it will show up most on the East-West and North-South seismograms and less so on the radial seismogram where there is no deformation caused in that direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Suffice to say, there are a lot of factors and &quot;tricks&quot; that seismologists use to distinguish these waves from one another. Becoming a master at this takes years of doing this, and being good at this could also result in a very nice paycheck.       &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-04-25T22:58:17.203" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="571" PostTypeId="1" CreationDate="2014-04-26T05:29:59.460" Score="54" ViewCount="9270" Body="&lt;p&gt;We all know that oil is an essentially nonrenewable resource over human time scales. However, I am currently working on an activity for high schoolers that teaches them to predict how long humans can continue extracting oil before running out (and what a sustainable rate of extraction would be).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To that end, does anyone know roughly how much oil is created each year, (in the entire crust, no matter how inaccessible)?&lt;/p&gt;&#xA;" OwnerUserId="288" LastEditorUserId="595" LastEditDate="2018-01-26T08:27:31.227" LastActivityDate="2018-01-26T08:27:31.227" Title="How much oil is created each year?" Tags="|resources|petroleum|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="573" PostTypeId="1" AcceptedAnswerId="575" CreationDate="2014-04-26T07:52:05.593" Score="17" ViewCount="3626" Body="&lt;p&gt;75% of the world's tornadoes occur in the USA, and within the USA these tornadoes are most likely to occur in particular regions of the country, such as the well known &quot;tornado alley&quot;.  The diagram below shows tornado activity in various parts of the USA, from 1950 to 1998.  It can be seen from the diagram below that most tornadoes occur on the Eastern half of the country.  Within this half of the country, there are regions with much greater tornado activity than others, highlighted in dark red in the diagram below, and includes the so called &quot;tornado alley&quot;.  Why is there a higher frequency of tornadoes in these regions compared to other regions of the USA and around the world?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/jtpfy.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="64" LastEditDate="2014-04-26T13:30:19.157" LastActivityDate="2014-05-25T02:15:09.170" Title="Why does the so called &quot;tornado alley&quot; exist?" Tags="|meteorology|tornado|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="574" PostTypeId="2" ParentId="546" CreationDate="2014-04-26T07:59:31.397" Score="10" Body="&lt;p&gt;The short answer is no.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tropical cyclones (TC) develop and persist in conditions favorable to them:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Low Coriolis parameter $f = 2\Omega \sin{\theta}$, where $\Omega$ is the angular velocity of Earth and $\theta$ is latitude. If $f$ is small, the centripetal force balances the pressure gradient force in the &lt;a href=&quot;http://en.wikipedia.org/wiki/Gradient_wind#Gradient_flow&quot;&gt;gradient wind balance&lt;/a&gt;, and the radius of curvature becomes small. While this is one of the reasons why TCs form in the tropics, that still does not prevent the storm to move North and re-curve into Western Europe or Northern California. This limits the latitude extent of the region of TC genesis to approximately 5-30 N (or S). This factor is most certain and not subject to climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) TCs get the energy from sensible and latent heat fluxes at the surface. Thus, they form over the ocean and it needs to be warm. Historically popular threshold of sea surface temperature (SST) necessary for a TC to develop was 26$^{\circ}$C. Nowadays, we know that this is not enough - TCs need a significant thickness of the upper ocean to be warm in order to get enough heat to be sustainable. Another reason why the ocean is more favorable for TCs than land is surface friction - the air flow over the ocean surface is typically much more aerodynamically smooth compared to over land. Low wind stress and high heat fluxes are key. Though the wind stress is not going to change, heat fluxes may increase if the ocean heat content in the tropics increases (for example, by weakening of the Meridional Overturning Circulation).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) TCs also need favorable atmospheric conditions in their environment - namely, high humidity (water vapor content) in the environmental air, and low wind shear (difference between wind in the upper and lower troposphere) facilitate TC genesis and longer life. These factors are, in my opinion, least understood of the three, especially in terms of their contribution to the vortex dynamics and vortex-mean flow interaction. This aspect is more likely to be subject to climate change compared to the others.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;All this being said, we may see a change in the occurrence frequency of TCs in the future, and/or a change in the distribution of the extreme weather events. However, the mechanisms in the climate that would lead to this change are still not well understood. It is unlikely though that the TCs will start forming in new regions around the world.&lt;/p&gt;&#xA;" OwnerUserId="192" LastActivityDate="2014-04-26T07:59:31.397" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="575" PostTypeId="2" ParentId="573" CreationDate="2014-04-26T13:29:35.673" Score="18" Body="&lt;p&gt;The kind of tornadoes &quot;tornado alley&quot; refers to are associated with supercell thunderstorms.  To first figure out why this region exists, we need to explore why this is a hotspot for supercells.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thunderstorms require energy and this energy comes in the form of convective available potential energy (CAPE).  This is simply the vertically integrated buoyancy of a parcel from its level of free convection (LFC) to its equilibrium level (EL).  Thunderstorms need CAPE but CAPE is not a great predictor of what kind of storm we get, that falls to vertical windshear.  Supercells form in environments with a 0-6 km shear (this measure if just a vector difference of the winds at these levels) greater than 20 m/s. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;CAPE is going to be maximized where you have warm, moist air at the surface and cold air aloft.  The Gulf of Mexico has plenty of water and it is common to find strong southerlies advecting this moisture into the US.  With a particularly strong low level jet, this moisture can be advected as far north as the Dakotas. As warm air is typically found toward the equator, this is also advecting warm air northward.  This results in a tongue of warm, moist air extending northward out of the gulf.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cool air aloft is provided by the Rockies and high plains.  In the boundary layer, mixing drives the temperature lapse rate toward dry adiabatic, while in the free troposphere the lapse rate is typically less than dry adiabatic.  The high elevations of the mountains mean that there are boundary layers and some layer of atmosphere with a dry adiabatic temperature profile.  These cool, dry adiabatic layers get advected by the westerlies aloft and end up on top of the warm moist air provided by southerlies out of the gulf. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This setup provides CAPE and the necessary shear (southerlies at low levels and westerlies aloft) for supercell thunderstorms.  However, not all supercells form tornadoes, and why is an area of active research.  Tornadoes will be favored with low LCL heights (lifting condensation level) and large low-level shear.  The occurrence of these environments combined with empirical data result in the area termed &quot;tornado alley&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The US isn't the only home to such a place.  There is a similar setup in Bangladesh where warm moist southerlies come off the ocean and cool adiabatic layers come from the high terrain in the region.  &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Because the atmosphere is giving a nice case study, here is an example of a sounding that demonstrates the above concepts.  This is from a radiosonde launched at &lt;a href=&quot;http://www.spc.noaa.gov/exper/soundings/14042812_OBS/&quot; rel=&quot;noreferrer&quot;&gt;Jackson, MS this morning at 12Z&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/fgYNT.gif&quot; alt=&quot;12Z JAN sounding&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Key features:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Boundary layer is well mixed (dry adiabatic temperature profile and constant water vapor mixing ratio)&lt;/li&gt;&#xA;&lt;li&gt;A cap (and a rather large one at that)&lt;/li&gt;&#xA;&lt;li&gt;An elevated mixed layer extended up to nearly 500 mb (nearly dry adiabatic temperature profile)&lt;/li&gt;&#xA;&lt;li&gt;Dry midlevels&lt;/li&gt;&#xA;&lt;li&gt;Southerlies at the surface&lt;/li&gt;&#xA;&lt;li&gt;Westerlies aloft&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Of note, the hodograph has a lot of low-level shear with almost all of the 0-6 km shear contained within the lowest 1 km.  The LCL is also somewhat low.  These are both favorable for tornado formation.  The big question is whether a storm will actually fire, as this sounding has considerable convective inhibition (CIN) from the large temperature inversion capping the boundary layer.  This is a morning sounding though and so there is plenty of time for the temperature to evolve.  The cap can be broken through pure solar heating, though requiring a temperature of 94 F to do so.  Throughout the day the boundary layer will be mixing with the cap, which will reduce its strength.  Moistening the boundary layer can also help decrease the CIN.  Aside from the large cap in the morning, this is a setup favorable for supercells and severe weather.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;And the result?  As of 2218Z, here is a view of the Jackson, MS radar:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/0sUu9.png&quot; alt=&quot;supercell&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a supercell (well, a line of them and a bit messy looking) with a possible tornado due west of Jackson and moving to the east.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;For a broader picture, lets also take a look at the 18Z NAM.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Surface moisture:&lt;br&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/x1lab.png&quot; alt=&quot;dewpoints&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This shows a tongue of moisture being advected by the southerlies out of the gulf.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Surface temperature (F):&#xA;&lt;img src=&quot;https://i.stack.imgur.com/blZn8.png&quot; alt=&quot;temp&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is also warm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Surface based CAPE:&lt;br&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/TYCMk.png&quot; alt=&quot;cape&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Put this together with midlevel lapse rates and we have lots of CAPE.  But do we have adequate shear?  Here is the 500 mb flow:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;500 mb height and relative vorticity:&lt;br&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/LgXr0.png&quot; alt=&quot;500mb&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Flow somewhat westerly, but direction is not as important as the magnitude.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Surface to 500 mb shear:&lt;br&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/XaA0t.png&quot; alt=&quot;shear&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And as this shows, we have plenty of shear.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a classic setup for severe weather and the frequency that this setup occurs and the resulting weather is how tornado alley earned its name.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2014-04-28T23:00:06.643" LastActivityDate="2014-04-28T23:00:06.643" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="576" PostTypeId="2" ParentId="565" CreationDate="2014-04-26T15:09:26.637" Score="12" Body="&lt;p&gt;[I am going to preface this by saying that I am not in one camp or the other in this discussion, as I think there are pros and cons to each side]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This links to the &quot;Gaia Theory&quot; proposed by James Lovelock, wherein the Earth is considered a self regulating organism. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this hypothesis, Earth is an organism in that it will try to maintain certain conditions.  These conditions include temperature (within a range suitable for life as we currently understand it), oxygen content of the atmosphere, water availability etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This does not mean that the ball of rock we are flying through space on is a living organism as we understand it, but rather that the various spheres of life (These are usually the biosphere (ecosystems), the atmosphere, the cryosphere (the poles, and other ice-bound areas), the hydrosphere(oceans), and the pedosphere(soil)) interact with each other in such a way that optimal conditions are maintained.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whilst the theory as a whole is not used today, it is recognised that feedbacks and interactions between different spheres occur, and are an important part of understanding Earth systems, and is studied in an area of science known as Earth System Science&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the initial arguments for this theory was that our atmosphere is not in chemical equilibrium, and that there must therefore be processes active to maintain oxygen levels at a steady state outside of equilibrium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a difficult topic, as it is important to stress that the Gaia hypothesis does not state the Earth is some sentient being consciously doing anything, rather that a complex set of interactions, abiotic and biotic, combine to maintain and regulate the planets temperature and atmospheric composition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An example of this regulation is chemical weathering, whereby carbon dioxide in the atmosphere falls in rain, and reacts with rocks, to form calcium bicarbonate, removing carbon from the short term carbon cycles.  The more surface rocks there are which are capable of this reaction, the more CO2 is removed from the atmosphere.&#xA;There is a hypothesis which says that at least once, the Earth has been covered largely in ice and snow, and this reaction (known as carbonation) is suspected to have played a part in the recovery of Earth.&#xA;The hypothesis (Snowball Earth) goes like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth became cooler, whether due to Milankovich cycles, volcanic activity, or solar output changes.  As this happened, ice began to form at the poles, changing the albedo, and reflecting more radiation back to space, this caused local cooling, and allowed for the growth of the ice sheets. As they spread, the albedo became higher on a larger scale, and the ice sheets eventually covered the two hemispheres, with a band of open ocean at the equator.&#xA;The earth was now very cold, but not completely empty of life, or without volcanic activity.  Life continued to respire CO2, and volcanoes continued releasing CO2.  Without rocks to remove it from rain, or ocean to absorb it, Carbon dioxide began to build up in the atmosphere.&#xA;As it built up (over millions of years), it began to warm the planet, which in turn began to melt the snow. As the snow and ice began to retreat to the poles, rocks, and open ocean were again available to remove the carbon dioxide from the atmosphere, and more photosynthetic organisms were able to survive, and remove more CO2 through photosynthesis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This lead to a stabilisation of the planets systems again, although, it may have gone too far, and swung back to a glacial period (although not a frozen earth), then moving back to a warm period before stabilising due to the tectonic movement of the continents northwards &lt;a href=&quot;http://www.brynmawr.edu/geology/documents/Hoffman1999JAES.pdf&quot;&gt;The break-up of Rodinia, birth of Gondwana, true polar &#xA;wander and the snowball Earth&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope this long ramble illustrates how there are a number of complex systems which all interact with each other to maintain conditions.  Whether we consider the sum of these systems an organism is an ongoing discussion, but, all organisms have the ability to regulate via various systems, and each of these systems has the potential to lead to chaotic positive feedbacks, and spiral out of control, although negative feedbacks usually keep everything running as normal. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have linked the Gaia theory webpage, and if you search for Daisyworld model, you will find a model which you can run to simulate feedbacks&#xA;It is up to you whether you think this collection of feedback systems is an organism, and this debate will likely run for decades more.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.gaiatheory.org/&quot;&gt;Gaia Theory Site&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="290" LastActivityDate="2014-04-26T15:09:26.637" CommentCount="15" ContentLicense="CC BY-SA 3.0" />
  <row Id="577" PostTypeId="2" ParentId="562" CreationDate="2014-04-26T19:20:50.690" Score="23" Body="&lt;p&gt;The first thing you should think about is how the accretionary disk cooled and the cosmochemical constraints this put on Earth (&lt;em&gt;But I am not going into details here&lt;/em&gt;). From studying meteorites it is apparent that the oldest meteorites don't show signs of chemical differentiation (e.g. melting, ...) and are thought to represent the solids that formed from the accretionary disk. Because of their characteristic round structures, chondrules, they are called Chondrites. The most chemically primitive Chondrites (e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Allende_meteorite&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Allende_meteorite&lt;/a&gt;) roughly have the same composition as Earth. This is why it is thought that Earth formed by accretion of these smaller chondritic objects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are also other meteorites called &quot;achondrites&quot;, meaning &quot;no chondrules&quot;. They show signs of chemical differentiation (we can find stony-, stony-iron-, and iron-achondrites). For this chemical differentiation to happen it is necessary to think of the meteorite as having a parent body, on which this differentiation took place. These parent bodies differentiated similar to earth into an iron-nickel core (iron-achondrites), an olivine-rich mantle (stony and stony-irons) and a silicate crust (stony-achondrites). Because differentiation takes time, it is somewhat unlikely that a parent body formed, was destroyed and the iron-core was recycled to nucleate Earth (Earth has roughly the same radiometric age as many meteorites). So your suggestion C would take quite some explaining. Also suggestion B is not temporally possible, because the magnetic field needs a liquid iron core to work and therefore only came into existence after the iron migrated to the core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/jt6v9.jpg&quot; alt=&quot;http://www.nature.com/nature/journal/v491/n7422/fig_tab/nature11565_F4.html - Current thoughts about differentiation&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A few words about iron-nickel. This has something to do with the abundance of elements in the accretionary disk (&lt;a href=&quot;http://upload.wikimedia.org/wikipedia/commons/e/e6/SolarSystemAbundances.png&quot; rel=&quot;noreferrer&quot;&gt;http://upload.wikimedia.org/wikipedia/commons/e/e6/SolarSystemAbundances.png&lt;/a&gt;). Iron and Nickel are very common elements. They are also siderophile, which means, that when a chondrite melts, the iron will try to separate from the sulfide- and silicate-melt. Because of the larger density of this melt, it will try to move towards the core of a planet. But it is very likely that other elements form a certain percentage of the core's chemical composition and it can be reckoned that this will be similar to some of the compositions of iron-meteorites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you get more interested in this I can fully recommend &quot;McSween, Harry Y. (1999). Meteorites and their parent planets (2. ed. ed.). Cambridge [u.a.]: Cambridge University Press. ISBN 978-0521583039.&quot; which is very enjoyable to read and because of its descriptive approach not outdated. The newer book is also very good &quot;Huss, Harry Y. McSween, Jr., Gary R. (2010). Cosmochemistry. Cambridge: Cambridge University Press. ISBN 978-0521878623.&quot;.&lt;/p&gt;&#xA;" OwnerUserId="23" LastEditorDisplayName="user889" LastEditDate="2015-02-18T09:28:07.107" LastActivityDate="2015-02-18T09:28:07.107" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="578" PostTypeId="2" ParentId="565" CreationDate="2014-04-27T02:03:30.523" Score="3" Body="&lt;p&gt;Interesting question. I think many issues of self-regulation and so forth have been addressed but what is really up for debate is whether the Earth can reproduce.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I answer with yes it is possible the Earth is an organism because it is possible for it to reproduce.  Through intelligent life that is able to develop technology, this life is able to reproduce the Earth (assuming living creatures are part of the Earth - like cells of the Earth).  We can think of the inanimate features of the Earth (e.g. atmosphere) like the blood of the organism that must supply the right Milieu intérieur for it's cells, the living creatures of the Earth.  The humans are analogous to the planets sex cells, because through humans, the most intelligent of Earth's species, the Earth is able to replicate itself through technology in the ways listed below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two potential ways that humans can be used to replicate the Earth.  The first way, is that because humans have adapted to fit in with the inanimate features of the Earth, if humans are to inhabit another existing planet, they must transform this planet into another Earth with the same properties of the Earth, that are compatible with human life, in order for that planet to be suitable for them.  Humans have evolved to be suited the Earth's conditions, and therefore any planet they wish to inhabit must have these same features of Earth.  &lt;strong&gt;It is a neat method of reproduction - evolve a species to need you, so it will later be forced to reproduce you.&lt;/strong&gt;  This effectively replicates the Earth.  The second way humans could replicate the Earth is directly producing another planet that has the same features of Earth using technology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While at present we have no record of living creatures having replicated a planet it is certainly plausible, and therefore it is plausible that the Earth is a living organism, given that it is possible for it to reproduce and self regulate through negative feedback mechanisms observable in nature.&lt;/p&gt;&#xA;" OwnerUserId="51" LastActivityDate="2014-04-27T02:03:30.523" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="580" PostTypeId="1" AcceptedAnswerId="582" CreationDate="2014-04-27T05:59:40.393" Score="64" ViewCount="511626" Body="&lt;p&gt;The enlightening image below is of a lightning strike slowed down at 10,000 frames per second.   It can be seen that the most intense flash produced from the lightening occurs in the direction from the ground up.  Why does this final &quot;ground-up&quot; strike occur and why is it so much brighter and faster than the initial part of strike heading towards the ground?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Qp2PB.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="51" LastActivityDate="2020-05-23T13:49:12.343" Title="Why does lightning strike from the ground-up?" Tags="|lightning|" AnswerCount="6" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="582" PostTypeId="2" ParentId="580" CreationDate="2014-04-27T06:51:41.457" Score="46" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Does lightning strike from the sky down, or the ground up?&lt;/strong&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The answer is both. Cloud-to-ground lightning comes from the sky down,&#xA;  but the part you see comes from the ground up. A typical&#xA;  cloud-to-ground flash lowers a path of negative electricity (that we&#xA;  cannot see) towards the ground in a series of spurts. Objects on the&#xA;  ground generally have a positive charge. Since opposites attract, an&#xA;  upward streamer is sent out from the object about to be struck. When&#xA;  these two paths meet, a return stroke zips back up to the sky. It is&#xA;  the return stroke that produces the visible flash, but it all happens&#xA;  so fast - in about one-millionth of a second - so the human eye&#xA;  doesn't see the actual formation of the stroke.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;strong&gt;Source:&lt;/strong&gt; &lt;a href=&quot;https://www.nssl.noaa.gov/education/svrwx101/lightning/faq/&quot; rel=&quot;noreferrer&quot;&gt;National Severe Storms Laboratory&lt;/a&gt; &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The reason is that when cloud-to-ground strike approaches the ground, the presence of opposite charges on the ground enhances the strength of the electric field and the &quot;downward leader&quot; strike creates bridge for the &quot;return stroke&quot;; this &lt;a href=&quot;http://en.wikipedia.org/wiki/Lightning#Upward_streamers&quot; rel=&quot;noreferrer&quot;&gt;per the wiki page for Lightning&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Cloud to cloud and Intra-Cloud Lightning&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/vBIiD.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Might be worth also noting that cloud-to-ground is not as common as &lt;strong&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Lightning#Cloud_to_cloud_.28CC.29_and_Intra-Cloud_.28IC.29&quot; rel=&quot;noreferrer&quot;&gt;Cloud to cloud (CC) and Intra-Cloud (IC&lt;/a&gt;)&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Lightning discharges may occur between areas of cloud without&#xA;  contacting the ground. When it occurs between two separate clouds it&#xA;  is known as inter-cloud lightning, and when it occurs between areas of&#xA;  differing electric potential within a single cloud it is known as&#xA;  intra-cloud lightning. Intra-cloud lightning is the most frequently&#xA;  occurring type.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Ground-to-Cloud&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/RM2Xe.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Appears that ground-to-cloud is possible, though normally only a result of a man-made object creating &quot;unnatural&quot; electric potential, and is the least common type of lightning.&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="284" LastEditDate="2014-04-27T19:42:58.883" LastActivityDate="2014-04-27T19:42:58.883" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="583" PostTypeId="2" ParentId="580" CreationDate="2014-04-27T09:49:58.243" Score="15" Body="&lt;p&gt;Lightning happens when the potential difference between the clouds and the grounds becomes too large. Once the voltage reaches a critical strength, the atmosphere can no longer act as an electrical insulator. First, a stepped leader is created at the base of the cloud which is a channel through which electrons in the cloud can travel to the ground. But while moving towards the ground, it searches for the most efficient(minimum electrical resistance) route possible. It does so by traveling 50-100 meters at a time then stopping for about 50 microseconds, then traveling another 50-100 meters. In this process it also branches out looking for the best route. As the stepped leader gets close to the ground, a positively charged traveling spark is initiated on some tall object (trees, towers etc) on the ground. The traveling spark moves upward and eventually connects with the stepped leader. Once the stepped leader and the traveling spark have connected, then electrons from the cloud can flow to the ground, and positive charges can flow from the ground to the cloud. This is known as return stroke. But this flow unlike the flow from up has a well defined shortest route now. This massive flow of electrical current occurring during the return stroke combined with the rate at which it occurs (measured in microseconds) rapidly superheats the completed leader channel, forming a highly electrically-conductive plasma channel. The core temperature of the plasma during the return stroke may exceed 50,000 K, which makes it shine so bright.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In your image above as well, you can see a lot of time is lost in looking for the route, whereas the return stroke just runs through the well defined channel and hence is much faster.&lt;/p&gt;&#xA;" OwnerUserId="206" LastEditorUserId="206" LastEditDate="2014-10-29T00:58:16.727" LastActivityDate="2014-10-29T00:58:16.727" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="586" PostTypeId="1" AcceptedAnswerId="872" CreationDate="2014-04-27T20:14:00.283" Score="12" ViewCount="240" Body="&lt;p&gt;It is known that when a large earthquake occurs, say $M \ge 9.0$, The surface waves travel around Earth over and over, &quot;ringing the surface like a bell&quot;. The GIF below is an example (&lt;a href=&quot;http://www.seismology.harvard.edu/research/research_normal_modes_source.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image Source&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/2z2t0.gif&quot; alt=&quot;enter image description here&quot;&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do these normal modes cause permanent deformation &lt;strong&gt;AWAY&lt;/strong&gt; from the earthquake source or does Earth affected simply slide back in place after the wave passes through it? If there is no permeant deformation, why does the surface near (but off source) crack and fault? &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="87" LastEditDate="2014-11-19T14:50:08.527" LastActivityDate="2014-11-19T14:50:08.527" Title="Do normal modes of oscillation cause permanent deformation?" Tags="|geophysics|seismology|geodesy|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="587" PostTypeId="2" ParentId="571" CreationDate="2014-04-27T21:47:12.547" Score="21" Body="&lt;p&gt;&lt;em&gt;I can't provide numbers, but a hopefully reasonable outline for your own calculations:&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All that is required for oil to form is a source-rock brought to the right depths in a sedimentary basin and the oil migrating into a host-rock. If it is economically profitable (See Footnote) it goes into the global reserve calculation. (Petroleum Sedimentology Winfried Zimmerle, H. Zimmerle)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/g94p1.jpg&quot; alt=&quot;Oil window&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All you need to calculate the oil production is an estimate of the volume of host-rock that is currently under those conditions in sedimentary basins around the world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/avQQz.gif&quot; alt=&quot;Sedimentary basins&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see there is a staggering area of Earth covered by sedimentary basins, and all those basins have a certain volume under oil generating conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You will probably also need a rough estimate of how much oil can come out of an average source-rock, and how much will be trapped in economically profitable host-rock traps. Maybe a factor that takes into account the basin type, would also help to improve the calculation (Compressional basins would have a lot of antiform traps, while extensional basins have tilted bed traps).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have the feeling that the total oil inventory of Earth is probably a Logistic function. Once all the oil traps are filled all the excessive oil is lost to migration or too much heat. Empty traps would mean that oil would find a place to accumulate. So it might even be a self-stabilizing system (but not in human-time-scale, but let's see how long we last).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think that this would yield an order-of-magnitude answer. It is possible that somebody already made these calculations and I would love to see the numbers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Footnote: Oil, like all resources, follows mining economics. If you earn money, you mine, if you loose money, you leave. This also means that if more money can be earned, there are also more deposits worth the effort. Calculations with today's reserves are almost useless, because they can't predict what people will be willing to pay for oil in the future. Even if mining becomes unprofitable, we might produce synthetic oil, just because it is a convenient chemical (energy stored in relation to mass, diffusivity, and danger). We kind of already have that with rapeseed oil, which sadly can get a better price to power rich countries cars, than feed poor countries people.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="23" LastActivityDate="2014-04-27T21:47:12.547" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="588" PostTypeId="2" ParentId="580" CreationDate="2014-04-27T23:58:04.460" Score="9" Body="&lt;p&gt;I'm pretty sure that lightning can go either way. We did the calculation in physics class, a bit of a back of the envelope calculation to be sure, but we came out with an electric field of 300,000 V/m being the electric field needed for lightning to form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What that means is, an electric field is created between the clouds and the ground by a build up of electrons on one of the surfaces. I believe that the electron build up can occur on either side. Once the field strength gets high enough, electrons begin to &quot;leak&quot; from one side of the air-gap (air does not normally conduct electricity unless it is highly charged) and that is what lightning is. You see the same affect in a capacitor that is overcharged, only instead of a thin sheet of paper, you are inside the insulator between plates. That is why you get a lot of noise (thunder of course), see a lot of light, and wireless communications and some electronics are affected.&lt;/p&gt;&#xA;" OwnerUserId="297" LastActivityDate="2014-04-27T23:58:04.460" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="589" PostTypeId="1" AcceptedAnswerId="598" CreationDate="2014-04-28T09:11:16.470" Score="12" ViewCount="620" Body="&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The theory of mantle plumes is useful (although controversial) in explaining the occurrence of intra-plate volcanoes.  The website &lt;a href=&quot;http://www.uhh.hawaii.edu/~kenhon/geol205/chain/default.htm&quot;&gt;here&lt;/a&gt; suggests that &quot;hotspots&quot; exist in fixed locations relative to one another in the core, and thus on a planet like Mars, where there are no tectonic plates, massive volcanoes will form above these &quot;hotspots&quot;, but on Earth moving tectonic plates give rise to strings of volcanoes above underlying &quot;hotspots&quot;.  The quote below is from the linked website:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The image on the right shows some of the other &quot;hot spots&quot; scattered&#xA;  about the floor of the Pacific Ocean. It is intriguing, that portions&#xA;  of island chains of similar age are parallel to each other. This&#xA;  suggest that the &quot;hot spots&quot; themselves remain mostly fixed with&#xA;  respect to each other, otherwise the chains might be expect to be&#xA;  curvilinear, or trend in different directions as the &quot;hot spots&quot;&#xA;  generating them moved independantly.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming that mantle plumes remain in fixed locations relative to one another at the core, is there any known pattern for how these mantle plumes are distributed relative to one another (or to fixed landmarks, e.g. axis of rotation), or do they appear to be distributed randomly?&lt;/p&gt;&#xA;" OwnerUserId="51" LastEditorUserId="105" LastEditDate="2014-04-30T19:28:50.477" LastActivityDate="2014-04-30T19:28:50.477" Title="Are mantle plumes distributed around the core randomly or in a known pattern?" Tags="|plate-tectonics|volcanoes|mantle|convection|mantle-plumes|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="590" PostTypeId="2" ParentId="573" CreationDate="2014-04-28T12:50:52.243" Score="11" Body="&lt;p&gt;In addition to @casey's answer regarding the conditions (which undoubtedly is the main answer), don't forget the issues of size and sampling.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the US, the tornadoes can be large and destructive. Therefore US authorities and citizens are very interested in tracking and reporting them. You also have good communication. In other words you get much higher reporting rates (unlike say the Asian steppes or Africa where communication and/or population is relatively sparse)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also compare to the UK which &lt;a href=&quot;http://www.ncdc.noaa.gov/climate-information/extreme-events/us-tornado-climatology&quot;&gt;gets more tornadoes by square kilometer than the US (NOAA URL)&lt;/a&gt;! So why don't we think of the UK as the Tornado Islands? Well first, they tend to be quite small, they are usually in relatively remote areas, and UK citizens &amp;amp; authorities are not looking intently for them (they're not a significant risk).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other-hand, I've lived in the UK for about 25 years including a fair amount of fell walking and have never knowingly seen or been near a UK tornado. I've lived in the Dallas-Fort Worth Metroplex over 10 years now, have heard the sirens many times, and although I didn't see it I have been within a block's distance of a destructive tornado once (luckily it wasn't on the ground at that point!). &lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2014-04-28T12:50:52.243" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="591" PostTypeId="2" ParentId="108" CreationDate="2014-04-28T13:07:33.487" Score="7" Body="&lt;p&gt;That the Earth is approximately an oblate spheroid is best explained by energy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Place a marble in a bowl. No matter where you place it, it will eventually come to rest at the bottom of the bowl. This is the position that minimizes the total energy of the marble subject to the constraint of being in the bowl. Suspend a chain between two posts. When the chain comes to rest it will take on a well-known shape, that of a catenary curve. This is the shape that minimizes the energy of the chain, subject to the constraint of being suspended between the two posts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you place the marble away from the bottom it will roll around for a while before coming to rest. If you pull the chain away from it's catenary shape it will swing back and forth for a while before coming to rest in that stable shape. The off-center marble and out-of-plane chain have greater potential energies than they do in their stable configuration. If at all possible, nature will attempt to minimize total potential energy. It's a consequence of the second law of thermodynamics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case of the Earth, that minimum energy configuration is a surface over which the sum of the gravitational and centrifugal potential energies are constant. Something that makes the Earth deviate from this equipotential surface will result in an increase in this potential energy. The Earth will eventually adjust itself back into that minimum energy configuration. This equipotential surface would be an oblate spheroid were it not for density variations such as thick and light continental crust in one place, thin and dense oceanic crust in another.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of force, the quantity we call &lt;i&gt;g&lt;/i&gt; is the gradient of the gravitational and centrifugal potential energies (specifically, $\vec g = -\nabla \Phi$). Since the Earth's surface is very close to being an equipotential surface and since that surface in turn is very close to being an oblate spheroid, gravitation at the poles is necessarily slightly more than it is at the equator.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This gravitational force will not be normal to the surface at places where the surface deviates from the equipotential surface. The tangential component of the gravitational force results in places where water flows downhill and in stresses and strains in the Earth's surface. The eventual responses to these tangential forces are erosion, floods, and sometimes even earthquakes that eventually bring the Earth back to its equilibrium shape.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Update: Why is this the right picture?&lt;/strong&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Based on comments elsewhere, a number of people don't understand why energy rather than force is the right way to look at this problem, or how the second law of thermodynamics comes into play.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are a number of different ways to state the second law of thermodynamics. One is that a system tends to a state that maximizes its entropy. For example, put two blocks at two different temperatures in contact with one another. The cooler block will get warmer and the warmer block will get cooler until both blocks are at the same temperature, thanks to the second law of thermodynamics. That uniform temperature is the state that maximizes the entropy of this two block system. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Those two blocks only have thermal energy. What about a system with non-zero mechanical energy? Friction is almost inevitably going to sap kinetic energy from the system. That friction means the system's mechanical energy will decrease until it reaches a global minimum, if any. For a rotating, dissipative, self-gravitating body, that global minimum does exist and it is a (more or less) oblate spheroid shape.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2014-04-30T19:40:38.683" LastActivityDate="2014-04-30T19:40:38.683" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="592" PostTypeId="2" ParentId="580" CreationDate="2014-04-28T19:53:09.753" Score="12" Body="&lt;p&gt;In the video, the downward strike created an ionized path. The brightness was less as the current was less because it was travelling through un-ionized air. The upward strike took the ionized path. The upward strike's current (brightness) was much greater as the electrons flowed along the ionized path as it had the least resistance. The current equals the voltage divided by the resistance. The less the resistance, the higher the current.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The apparent speed difference is because the upward strike took a more direct path. The camera shows a two dimensional image and does not show the motion of the lightning away from or towards the camera. In a video when you see an object coming directly towards or away from the camera, you see the object get larger or smaller. The size differences in the video are not large enough to show the direction towards or away from the camera.&lt;/p&gt;&#xA;" OwnerUserId="306" LastActivityDate="2014-04-28T19:53:09.753" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="593" PostTypeId="2" ParentId="178" CreationDate="2014-04-29T14:42:00.363" Score="11" Body="&lt;p&gt;The density of a water parcel evolves as it moves in the ocean. A parcel of bottom water (e.g., Antarctic Bottom Water (AABW) the densest water mass) is much denser than the surrounding water when it is formed near the surface (in the case of the AABW in polynyas and below the ice shelf in the Weddell and Ross Seas). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the parcel of AABW sinks, it flows down the Antarctic continental shelf and slope and moves north along the bottom at speeds of 2-8 cm/s. The issue is that the water parcel of AABW will be interacting and mixing with the surrounding water.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, a parcel of AABW that when it was formed had a temperature of around -0.8°C and a salinity of 34.7, will get mixed with warmer water masses (e.g., Antarctic Intermediate Water, North Atlantic Deep Water) and as it becomes less dense it will be more easily mixed with the surroundings.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have surrounding waters that are more saline and with comparable temperatures, then the less saline water parcel (modified AABW for instance compared to NADW) will rise. The interior circulation of the ocean is predominantly driven by thermohaline processes (differences in density) and the thermal wind equation can be used as a simplification of the dynamics, especially away from the edges (surface, bottom).&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2014-05-05T19:01:18.880" LastActivityDate="2014-05-05T19:01:18.880" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="594" PostTypeId="2" ParentId="25" CreationDate="2014-04-29T14:53:47.700" Score="6" Body="&lt;p&gt;I think the simplest answer is through water mass formation, the resulting &lt;a href=&quot;http://en.wikipedia.org/wiki/Thermohaline_circulation&quot; rel=&quot;nofollow&quot;&gt;thermohaline circulation&lt;/a&gt;, mixing caused by wind predominantly in shallow regions, and through &lt;a href=&quot;http://en.wikipedia.org/wiki/Ocean_current#Downwelling_of_deep_water_in_polar_regions&quot; rel=&quot;nofollow&quot;&gt;downwelling processes&lt;/a&gt;. The heat exchanged with the atmosphere in the surface layers determine the temperature of the near-surface water. From there, mixing (caused by wind, for instance) will transfer some of the heat to lower layers in the ocean. In the case of areas of water mass formation, the sinking of surface waters is usually enhanced. When the water masses are away from the ocean boundaries (surface and bottom), then the thermohaline circulation controls the transport and exchange between water parcels and thus the heat transfer.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="4487" LastEditDate="2015-11-08T12:08:12.673" LastActivityDate="2015-11-08T12:08:12.673" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="595" PostTypeId="2" ParentId="16" CreationDate="2014-04-29T15:08:14.060" Score="7" Body="&lt;p&gt;Most of the heat balance calculations in the ocean use satellite-measured sea surface temperature (SST). This provides global temperature fields with daily variations. The interior heat content is determined using &lt;a href=&quot;http://www.argo.net/&quot;&gt;ARGO floats&lt;/a&gt; (as mentioned before), long-term mooring arrays (e.g., &lt;a href=&quot;http://www.pmel.noaa.gov/tao/&quot;&gt;TAO&lt;/a&gt;, &lt;a href=&quot;http://www.pmel.noaa.gov/pirata/&quot;&gt;PIRATA&lt;/a&gt;) and extensive field cruises (e.g., &lt;a href=&quot;http://www.nodc.noaa.gov/woce/&quot;&gt;WOCE&lt;/a&gt;) that use &lt;a href=&quot;http://www.whoi.edu/instruments/viewInstrument.do?id=1003&quot;&gt;CTDs&lt;/a&gt; to measure temperature down to several thousand meters deep. Very few people use bottle samples (e.g., Nansen or Niskin bottles) for heat content estimates (they are used for sensor calibration for instance).&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-04-29T15:08:14.060" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="596" PostTypeId="1" AcceptedAnswerId="597" CreationDate="2014-04-29T16:03:52.523" Score="8" ViewCount="143" Body="&lt;p&gt;Can anyone tell me the concentration of silver in uncontaminated water ways, or treated tap water in the united kingdom? sources would be desirable too&lt;/p&gt;&#xA;" OwnerUserId="309" LastEditorUserId="140" LastEditDate="2014-04-29T19:11:25.733" LastActivityDate="2014-04-29T19:11:25.733" Title="What is the concentration of silver in tap or freshwater in the United kingdom" Tags="|ocean|geochemistry|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="597" PostTypeId="2" ParentId="596" CreationDate="2014-04-29T16:28:50.853" Score="7" Body="&lt;p&gt;Monitoring results from UK groundwaters 1996-2007, Silver:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sites 2929&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Samples 19420&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Min &amp;lt;0.04 µg/l&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Max 79.6 µg/l&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Average 0.457 µg/l&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://dwi.defra.gov.uk/research/completed-research/reports/DWI70_2_215_Monitoring_Data.pdf&quot;&gt;Source - Defra&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Routine monitoring for trace elements in drinking water is only&#xA;  conducted for the elements specified in the Water Supply (Water&#xA;  Quality) Regulations. Specified elements include antimony, arsenic,&#xA;  boron, cadmium, chloride, chromium, copper, fluoride, iron, lead,&#xA;  manganese, mercury, nickel, selenium and sodium. Monitoring for other&#xA;  elements will only normally be conducted in response to specific&#xA;  identified risk. Recently DWI has funded investigations of uranium1&#xA;  and molybdenum2 in drinking water in response to recent developments&#xA;  in WHO guideline values. Both these studies showed a good level of&#xA;  compliance should the WHO guideline value be adopted as a standard.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Also...&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Water companies also conduct raw water monitoring and these results&#xA;  are reported to Drinking Water Inspectorate. Preliminary analysis suggests most of the &#xA;  raw water monitoring relates to elements already covered by the&#xA;  regulations but a few companies monitor for additional elements in raw&#xA;  water. A summary of the additional elements and (number of companies&#xA;  monitoring). Silver (4).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://randd.defra.gov.uk/Default.aspx?Menu=Menu&amp;amp;Module=More&amp;amp;Location=None&amp;amp;Completed=0&amp;amp;ProjectID=17665&quot;&gt;Source - Defra 2&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Average silver concentrations in natural waters are 0.2-0.3 µg/litre.&#xA;  Silver levels in drinking-water in the USA that had not been treated&#xA;  with silver for disinfection purposes varied between &quot;non-detectable&quot;&#xA;  and 5 µg/litre. In a survey of Canadian tapwater, only 0.1% of the&#xA;  samples contained more than 1-5 µg of silver per litre. Water treated&#xA;  with silver may have levels of 50 µg/litre or higher; most of the&#xA;  silver will be present as nondissociated silver chloride.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.who.int/water_sanitation_health/dwq/chemicals/silver.pdf&quot;&gt;Source - WHO&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="140" LastEditorUserId="140" LastEditDate="2014-04-29T18:28:15.653" LastActivityDate="2014-04-29T18:28:15.653" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="598" PostTypeId="2" ParentId="589" CreationDate="2014-04-29T16:53:14.030" Score="10" Body="&lt;p&gt;First of all, the idea of a fixed &quot;hotspot&quot; reference frame is (albeit reluctantly) falling out of favour on a geological timescale; see e.g. &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/GM121p0339/summary&quot;&gt;http://onlinelibrary.wiley.com/doi/10.1029/GM121p0339/summary&lt;/a&gt; (&quot;As studies of plate motions have advanced, however, it has become clear that the global hotspots do not stay fixed relative to each other...&quot;) and &lt;a href=&quot;http://adsabs.harvard.edu/abs/2010AGUFM.U51A0010S&quot;&gt;http://adsabs.harvard.edu/abs/2010AGUFM.U51A0010S&lt;/a&gt; (&quot;Hotspot reference frames can only be confidently tied back to about 130 Ma and there is evidence that mantle plumes have moved relative to each other.&quot;) Global Moving Hotspot Reference Frames are in the process of being built, see e.g. &lt;a href=&quot;http://adsabs.harvard.edu/abs/2010AGUFMGP24A..03D&quot;&gt;http://adsabs.harvard.edu/abs/2010AGUFMGP24A..03D&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly, identifiable patterns in the distribution of mantle plumes are an area of active research: &lt;a href=&quot;https://www.egu.eu/awards-medals/division-outstanding-young-scientists-award/2014/rhodri-davies/&quot;&gt;this year's EGU medal for outstanding young scientist was awarded to Rhodri Davies for his work in this area&lt;/a&gt;. Key to most arguments are the presence of &lt;a href=&quot;https://en.wikipedia.org/wiki/Large_Low_Shear_Velocity_Provinces&quot;&gt;Large Low Shear Velocity Provinces&lt;/a&gt; (LLSVPs) in the lower mantle, historically assumed to be &quot;slab graveyards&quot; (thermochemical piles created when subducting slabs pool in the lower mantle). The suggestion that these areas were both chemically and thermally distinct from surrounding mantle focussed attention on their margins as a highly probable location for the formation of mantle plumes. However, recent findings (by and cited extensively by Rhodri Davies) increasingly support the idea that these piles are thermal features &lt;em&gt;only&lt;/em&gt;, with no chemical difference to surrounding mantle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rhodri Davies' research revisits past studies that found hotspots were concentrated along the edges of LLSVPs, and has thoroughly demonstrated that these conclusions are not robust, e.g. to choice of hotspot catalogue, prescribed angular search tolerance (between surface expression and imaged margin), (arbitrary) depth of analysis, and (arbitrary) shear-wave velocity contour. Via Monte Carlo simulations he rules out hotspots being drawn from the margins of the Pacific LLSVP, but cannot rule out the possibility that hotspots are preferentially drawn from the entire areal extent of LLSVPs in both the Pacific and the Atlantic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;RD &amp;amp; his team conclude that present-day hotspot locations are controlled by ancient subduction, rather than the current margins of LLSVPs - which are demonstrated via dynamical simulations to be mobile, even in the presence of dense chemical heterogeneity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(As a side note, both &quot;hotspots&quot; and &quot;mantle plume&quot; are contested terminology, it's true - but the vast majority of geoscientists believe that mantle plumes &lt;em&gt;do&lt;/em&gt; exist. There is complexity to that view, in that the consensus does not require &lt;em&gt;all&lt;/em&gt; intraplate volcanism to be the result of atypically hot mantle -- but the idea that mantle plumes simply do not exist, as espoused by &lt;a href=&quot;http://mantleplumes.org&quot;&gt;mantleplumes.org&lt;/a&gt;, does not have wide acceptance.)&lt;/p&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-04-29T16:53:14.030" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="599" PostTypeId="5" CreationDate="2014-04-29T16:55:14.247" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-29T16:55:14.247" LastActivityDate="2014-04-29T16:55:14.247" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="600" PostTypeId="4" CreationDate="2014-04-29T16:55:14.247" Score="0" Body="Questions about anthropogenic and natural climate change, which increases the global average of near surface air temperature." OwnerUserId="124" LastEditorUserId="20" LastEditDate="2014-05-03T20:44:20.953" LastActivityDate="2014-05-03T20:44:20.953" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="601" PostTypeId="1" CreationDate="2014-04-29T20:30:31.220" Score="12" ViewCount="656" Body="&lt;p&gt;I read that the mathematical definition of bifurcation is that, at a critical value of a parameter that governs the dynamical system, the system changes to a topologically different system than the previous.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I recognize that the scope of this question is large, but still:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is this phenomenon relevant in atmospheric sciences?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One can say that since the topology of the systems orbit changed, so different, previously unaccounted for, phenomena will show up - but that is obvious. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why, if at all, should a climatologist trying to predict a long term time series keep bifurcation in mind, given they can also compute the results numerically within the limits of precision, without explicitly worrying about bifurcation?&lt;/p&gt;&#xA;" OwnerUserId="313" LastEditorUserId="105" LastEditDate="2014-04-29T23:11:56.973" LastActivityDate="2014-04-29T23:11:56.973" Title="Bifurcation Scenarios in the Atmosphere" Tags="|atmosphere|meteorology|climate|nwp|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="602" PostTypeId="2" ParentId="601" CreationDate="2014-04-29T21:34:50.200" Score="6" Body="&lt;p&gt;Bifurcation is relevant to the atmosphere because it effects the predictability of the evolution of the atmosphere.  I can't speak to its merits with climate models, but with weather it is quite important.  As Lorenz discovered, the atmosphere is chaotic and numerical prediction is very sensitive to the initial conditions.  If the initial conditions are close to the bifurcation point, the solution can be wildly different and this leads to poor predictability.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In particular, weather models assimilate observations and each observation is a value and an uncertainty.  When the uncertainty contains the bifurcation point that essentially means for that particular scenario the instrument error is such that the instrument can provide an observation on either side of the bifurcation. This can be explored with ensemble modeling where many models are run with slightly different initial conditions (or slightly different models, or both) and leads to a large spread in the ensemble and low confidence in the forecast.  Our atmosphere can be more sensitive than the instruments we use to measure it can detect.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll try to dig up some references to presentations I've seen that show hurricane dissapation / rapid strengthening determined by differences in gulf of Mexico observations smaller than the instrument error reporting them.  For more NWP-centric studies, you can search for articles on &lt;em&gt;predictability&lt;/em&gt;.  I know there should be a couple by &lt;a href=&quot;http://scholar.google.com/citations?user=RL0foHcAAAAJ&amp;amp;hl=en&quot;&gt;Dr. Fuqing Zhang (PSU)&lt;/a&gt; and I'll edit when I can point to some specific articles.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-04-29T21:34:50.200" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="603" PostTypeId="2" ParentId="601" CreationDate="2014-04-29T21:43:18.653" Score="4" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Bifurcation_theory&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bifurcation&lt;/a&gt; is a characteristic of &lt;a href=&quot;http://en.wikipedia.org/wiki/Chaos_theory&quot; rel=&quot;nofollow noreferrer&quot;&gt;chaotic systems&lt;/a&gt;.  To quote the Wikipedia article on chaos theory&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Chaos theory studies the behavior of dynamical systems that are highly sensitive to initial conditions—a paradigm popularly referred to as the butterfly effect. Small differences in initial conditions (such as those due to rounding errors in numerical computation) yield widely diverging outcomes for such dynamical systems, rendering long-term prediction impossible in general. This happens even though these systems are deterministic, meaning that their future behavior is fully determined by their initial conditions, with no random elements involved. In other words, the deterministic nature of these systems does not make them predictable.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The climate of the Earth is one of these chaotic systems.  What happens at a bifurcation point in a chaotic system is that a tiny change of the input parameters to the model results in an entirely different outcome.  For this reason it is important to understand the bifurcation points of the system in order to understand when your model has no predictive power.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most classic example of a chaotic system which exhibits bifurcation is the &lt;a href=&quot;http://en.wikipedia.org/wiki/Logistic_map&quot; rel=&quot;nofollow noreferrer&quot;&gt;logistic map&lt;/a&gt;.  This equation is used to model demographics or population growth in biological systems.&lt;br&gt;&#xA;$$&#xA;x_{n+1}=r x_n(1-x_n)&#xA;$$&#xA;The outcomes of this equation for different values of the parameter $r$ are shown in the plot below (taken from the Wikipedia article cited above).  You can see that after $r$ goes over $3$ the outcomes of each successive iteration become completely unpredictable.  The first two bifurcations in this example are at $r=3$ and $r=3.5$.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/8IBKa.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="53" LastActivityDate="2014-04-29T21:43:18.653" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="604" PostTypeId="2" ParentId="349" CreationDate="2014-04-30T00:04:11.703" Score="3" Body="&lt;p&gt;A rock is a rock.  It is made of rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A rock is the solid mineral material forming part of the surface of the earth and other similar planets, exposed on the surface or underlying the soil or oceans.&lt;/p&gt;&#xA;" OwnerUserId="314" LastActivityDate="2014-04-30T00:04:11.703" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="605" PostTypeId="1" CreationDate="2014-04-30T02:50:03.997" Score="15" ViewCount="1613" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Rain_shadow&quot;&gt;Rain shadows&lt;/a&gt; are dry areas on the lee side of mountains. Due to humid air condensing and precipitating as they are lifted up and over the mountains, they lose moisture by the time they reach the lee side, forming a relatively dry area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What factors affect the size of this dry area, and how?&lt;/p&gt;&#xA;" OwnerUserId="85" LastActivityDate="2015-01-13T07:10:21.967" Title="What factors affect the size of rain shadows?" Tags="|meteorology|climate|precipitation|" AnswerCount="2" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="606" PostTypeId="1" AcceptedAnswerId="611" CreationDate="2014-04-30T03:36:34.833" Score="13" ViewCount="1028" Body="&lt;p&gt;In the &lt;a href=&quot;https://en.wikipedia.org/wiki/Scandinavian_mountains&quot;&gt;Scandinavian mountains&lt;/a&gt;, there is a strong effect of &lt;a href=&quot;https://en.wikipedia.org/wiki/Orographic_lift&quot;&gt;orographic precipitation&lt;/a&gt;.  The west receives far more precipitation than the east.  This difference can be a factor 5 or more in some places.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But when I observe the locations of glaciers, they seem to be mostly on the &lt;em&gt;eastern&lt;/em&gt; side.  An example can be found by studying &lt;a href=&quot;http://kart.statkart.no/adaptive2/default.aspx?gui=1&amp;amp;lang=1&amp;amp;minX=596866.3125&amp;amp;minY=7568020.71875&amp;amp;maxX=632154.9375&amp;amp;maxY=7588373.03125&amp;amp;layers=&amp;amp;baselayer=100&amp;amp;visibleOLOverlays=avinetBasemap100002,avinetBasemap2&quot;&gt;the Norwegian topographic map near Narvik&lt;/a&gt;.  Almost all the glaciers, on Rienatčohkka, Storsteinsfjellet, Ristačohkka, and others, are on the east side of the mountains, while the west side is mostly bare.  If the precipitation is orographic, shouldn't it fall on the west side?  Then why is the east side more glaciated?  Is this a typical effect, or is there a strange situation locally?&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="81" LastEditDate="2014-04-30T13:46:31.867" LastActivityDate="2017-03-25T19:34:17.377" Title="Why do those glaciers form on the lee side of the mountains?" Tags="|precipitation|glaciology|glacier|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="607" PostTypeId="2" ParentId="178" CreationDate="2014-04-30T04:53:35.447" Score="5" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Upwelling&quot; rel=&quot;noreferrer&quot;&gt;Upwelling&lt;/a&gt; of deep ocean water can be driven by the wind. &lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-04-30T04:53:35.447" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="608" PostTypeId="1" AcceptedAnswerId="612" CreationDate="2014-04-30T07:29:14.630" Score="30" ViewCount="6430" Body="&lt;p&gt;There are many movies about global warming, which say that melting of all polar ice would cause the whole world to suffer a huge flood. According my research (teachers, TV, Internet) people hold one of these two viewpoints:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;There will be a huge flood, because the polar ice has a huge volume.&lt;/li&gt;&#xA;&lt;li&gt;There won't be any flood, because the volume of polar ice is small compared to the whole world.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Which one is correct, if all the polar ice melts? What would be the approximate sea-level change (in meters), if this were to happen?&lt;/p&gt;&#xA;" OwnerUserId="132" LastEditorUserId="349" LastEditDate="2014-05-01T10:25:46.730" LastActivityDate="2019-05-09T11:43:48.343" Title="How much will sea level rise if all the polar ice melts?" Tags="|global-warming|sea-level|climate-change|cryosphere|ice-sheets|" AnswerCount="6" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="609" PostTypeId="1" CreationDate="2014-04-30T08:46:46.353" Score="8" ViewCount="158" Body="&lt;p&gt;There are numerous measurement systems available for measuring groundwater levels (head / stage). What period of time should measurements be collected in order to draw solid conclusions about the average groundwater level, min/ max, trends, etc?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would reckon at least one year to take account for seasonal effects, although longer would be preferable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Long measurement periods (several years) are often unwanted, due to the need for fast results. So the optimum between research duration and solid conclusions lies somewhere in between I presume. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT:&#xA;There is a factory which is investigating the possible use of groundwater for their industrial process. Enviromental law dictates that the effects of the substraction on the long term groundwaterlevels have to be investigated. &#xA;The first question then becomes: what is the current long term variability in groundwaterlevel? Only then we can continue with answering what the effects of the substraction will be.&lt;/p&gt;&#xA;" OwnerUserId="134" LastEditorUserId="134" LastEditDate="2014-05-01T06:25:52.277" LastActivityDate="2014-05-09T20:00:53.340" Title="Measurement of groundwater levels" Tags="|measurements|groundwater|" AnswerCount="2" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="610" PostTypeId="2" ParentId="608" CreationDate="2014-04-30T10:19:35.990" Score="4" Body="&lt;p&gt;I had been to a conference at the NY American Museum of Natural History and the guest speaker at the science convention estimates about 220-230 feet (66 - 69 meters).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://science.howstuffworks.com/environmental/earth/geophysics/question473.htm&quot; rel=&quot;nofollow&quot;&gt;If the polar ice caps melted, how much would the oceans rise?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="318" LastEditorUserId="6093" LastEditDate="2016-10-06T15:26:21.307" LastActivityDate="2016-10-06T15:26:21.307" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="611" PostTypeId="2" ParentId="606" CreationDate="2014-04-30T10:22:43.977" Score="13" Body="&lt;p&gt;The key is with wind-drifting. The predominant westerlies cause snow to drift into protected places. We should perhaps recall that glaciers exist because they are essentially snow-catchers in a landscape that is sufficiently suitable for some of the snow to survive the summer melt period. The drifting and depositing of snow on the eastern side of mountains thus favours formation of glaciers in such locations. If you take a trip using Google Earth into the Swedish mountains to the East of the area you describe you will see that glaciers are also in north and south-trending valleys where of course they catch snow for the same reason. In this case it is the larger scale geomorphology that dictates the location and direction of glaciers. The latter implies that a glacier is not just formed in the lee direction of the predominant wind direction but also requires a suitable landscape geomorphology which affects the location of where the glacier forms.&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2014-04-30T10:22:43.977" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="612" PostTypeId="2" ParentId="608" CreationDate="2014-04-30T10:34:43.347" Score="33" Body="&lt;p&gt;Using the latest numbers from the &lt;a href=&quot;http://www.climatechange2013.org/images/report/WG1AR5_Chapter04_FINAL.pdf&quot;&gt;2013 IPCC report (Ch. 4, the Cryosphere)&lt;/a&gt;, Antarctica contains 58.3 m of sea level equivalent (sle) and Greenland 7.36 m sle. Remaining glaciers provide an additional 0.41 m sle. In total and adding very minor contributions from permafrost etc. the total comes out to approximately 66.1 m sle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: Just to be complete: If one by &quot;pole ices&quot; also includes sea or other floating ice apart from glaciers terminating in the sea, the contribution from those components to sea level is zero.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="81" LastEditDate="2014-04-30T11:52:44.250" LastActivityDate="2014-04-30T11:52:44.250" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="613" PostTypeId="2" ParentId="178" CreationDate="2014-04-30T12:35:17.210" Score="8" Body="&lt;p&gt;I wonder why Eckmann transport is not mentioned. You can have wind flowing parallely  to the coastlines, for example, along a NS direction. Water driven by this wind will be subject to coriolis force and deflect sideways, and that will produce a net normal component of water movement to the wind direction. This is Ekmann transport, very simply stated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This way, surface water is moved away, and that creates a pressure gradient, wo balance which, water sinks where it is driven to, and rises where it is driven from. This is the Ekmann transport driven upwelling / downwelling.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The AABW is subject to antarctic eastward flowing polar winds and the resulting northward Ekmann transport. So the surface water is driven north, and that is creating a pressure gradient, which causes increases pressure in just the north of AABW in Indian / south pacific ocean, and that pressure is as well acting on the - albeit from the side - to the AABW, which causes it to rise.&lt;/p&gt;&#xA;" OwnerUserId="313" LastActivityDate="2014-04-30T12:35:17.210" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="614" PostTypeId="2" ParentId="608" CreationDate="2014-04-30T12:37:32.450" Score="16" Body="&lt;p&gt;As Peter Jansson explains, sea level rise purely due to melting of land-based global ice works out &quot;to approximately 66.1 m sle.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An issue with respect to sea-level rise that isn't often mentioned (especially not in disaster movies!) is that &lt;em&gt;thermal expansion&lt;/em&gt; of the sea - i.e. water expanding as global temperatures rise - will also have a huge effect: see &lt;a href=&quot;http://www.climatechange2013.org/images/report/WG1AR5_Chapter03_FINAL.pdf&quot;&gt;section 3.7 of the IPCC report&lt;/a&gt;. The magnitude of this effect is of course dependent on the magnitude of rise in global average temperature.&lt;/p&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-04-30T12:37:32.450" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="615" PostTypeId="1" CreationDate="2014-04-30T13:09:30.200" Score="6" ViewCount="79" Body="&lt;p&gt;I learned that human activities produce gases that deplete the ozone layer, and create the greenhouse layer, which increases the world's temperature. (And seems real , now in Thailand it's 35 degree Celsius)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/60RHI.gif&quot; alt=&quot;Greenhouse Effect occurs&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now. I want to know that if there isn't any human activities that causes changes to atmosphere , Which statement is correct?&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The earth will be cool. As the same temperature as before the industries age. It's only human's fault that makes the world hotter.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The earth will be gradually hotter. In the past there are &quot;ice age&quot;. And Now there might just be &quot;hot age&quot;. Humans activities are just make the process faster. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Can we point out which statement is currently correct? If not , you can add your own statement and if you are able to explain , do it.&lt;/p&gt;&#xA;" OwnerUserId="132" LastEditorUserId="124" LastEditDate="2014-04-30T13:56:00.550" LastActivityDate="2014-04-30T13:56:00.550" Title="Is global warming occuring only because of humans?" Tags="|atmosphere|temperature|global-warming|" AnswerCount="0" CommentCount="3" ClosedDate="2014-04-30T20:08:58.733" ContentLicense="CC BY-SA 3.0" />
  <row Id="616" PostTypeId="2" ParentId="605" CreationDate="2014-04-30T13:12:21.857" Score="5" Body="&lt;p&gt;Of course, first you will need a collision zone where moist air collides with dry air - and therefore you will need to consider a considerable air flow in the opposite direction to the flow responsible for the rain shadow. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, in Eurasia, the Himalayan rain shadow extends up to the Kazhak steppes, until regional climatic effects of the Black Sea and Caspian Sea moderate the dryness. The Russian heartlands are blessed with the Dvina-Sukhona river; which starts at the lake Kubenskoye; which is blessed from Baltic Airs, still under the effects of the westerlies: thus you do not directly have a moist airstream colliding with the dry air from the opposite direction, but from the side.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In contrast, the German northeast, Mecklenburg-Vorpommern is within the rain shadow of the central German Harz mountains - but the river Oder is also inside the rain shadow. This brings us to the second point: topological relief. Is it sloping towards the rain shadow, such that the rain water from the other side drains into the rain shadow?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this case, sooner or later you will form rivers - and lakes, unless the river meets the sea very quickly (as in the case of Germany and the Baltics). As soon as you have lakes, the rain shadow will be moderated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Taking yet another example, the Kalaharis: east of Namibian Great Escarpment, and west of Highveld/Drakensberg. Thus Kalahari lies within a rain shadow from both east and west - and despite the river Okawango flowing in it, the climate is not moderated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So there are uncountably many factors that contribute to your question.&lt;/p&gt;&#xA;" OwnerUserId="313" LastEditorUserId="20" LastEditDate="2014-04-30T22:10:53.053" LastActivityDate="2014-04-30T22:10:53.053" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="617" PostTypeId="2" ParentId="608" CreationDate="2014-04-30T13:25:59.337" Score="11" Body="&lt;p&gt;(I can't comment on @kaberett answer as a guest)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Don't forget the odd effect that as ice melts and the water warms from 0C to 4C, that water will &lt;em&gt;contract&lt;/em&gt; slightly, dropping sea level a bit (at least, locally). Once it gets above 4C, it will start expanding again. If the oceans overall cool a bit due to cold meltwater mixing in, they too will contract until they start warming again. Note that this contraction won't save us from a huge rise in sea level in any case, and eventually the meltwater will be mixed in and start warming up beyond 4C, and expand.&lt;/p&gt;&#xA;" OwnerUserId="280" LastActivityDate="2014-04-30T13:25:59.337" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="618" PostTypeId="2" ParentId="608" CreationDate="2014-04-30T13:43:11.167" Score="7" Body="&lt;p&gt;While &lt;a href=&quot;https://earthscience.stackexchange.com/a/614/319&quot;&gt;@kaberett's&lt;/a&gt; and &lt;a href=&quot;https://earthscience.stackexchange.com/a/617/319&quot;&gt;@Phil Perry's&lt;/a&gt; answers are technically true, keep in mind 2 important issues:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the oceans are so vast and so deep that it literally takes decades if not centuries for them to warm up or cool down. This is called Thermal Inertia - see &lt;a href=&quot;http://www.skepticalscience.com/Climate-Change-The-40-Year-Delay-Between-Cause-and-Effect.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;a much more in-depth explanation about it&lt;/a&gt;. Basically, you'll only see the effect of current rising temperatures when you're too old to give a damn.&lt;/li&gt;&#xA;&lt;li&gt;melting ice from the poles will indeed have a significant impact on sea level, eventually (see the first point above). But that's not the problem. The problem is that the combination of fresh water (from the ice) and salt water (already in the oceans) will completely screw up the very large and very important ocean currents, also known as &lt;a href=&quot;http://en.wikipedia.org/wiki/Thermohaline_circulation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Thermohaline circulation&lt;/a&gt;. Once this happens... well, let's just say living in a smelly swamp will be considered luxury...&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The 66 meters calculation seems about right :) .&lt;/p&gt;&#xA;" OwnerUserId="319" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-04-30T14:49:26.377" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="619" PostTypeId="1" CreationDate="2014-04-30T14:31:16.443" Score="9" ViewCount="62" Body="&lt;p&gt;I'm looking for a lab experiment design that shows how to measure the presence of semi-volatile solids in water (and not sludge or soil or solids). All I have found so far are chromotography/mass spectometry methods. Are there any ‘less advanced’ methods? My professor says there are, but I can’t find them. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anybody here know of such methods, or where I should start looking for them?&lt;/p&gt;&#xA;" OwnerUserId="322" LastEditorUserId="64" LastEditDate="2014-04-30T14:49:17.060" LastActivityDate="2014-04-30T23:06:44.713" Title="Lab procedure for analyzing/assessing the presence of semi-volatile solids" Tags="|measurements|models|hydrology|water-table|rivers|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="620" PostTypeId="1" AcceptedAnswerId="978" CreationDate="2014-04-30T14:45:46.860" Score="8" ViewCount="239" Body="&lt;p&gt;After scirus is closed, which search engine do you all use?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know of Arxiv, and ADS, which only partially overlaps with Earth Science related issues. Any other recommendations would be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="313" LastEditorUserId="48" LastEditDate="2014-05-03T00:55:49.830" LastActivityDate="2014-05-21T23:38:18.007" Title="Earth Science Search Engine" Tags="|resources|informatics|" AnswerCount="2" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="621" PostTypeId="1" CreationDate="2014-04-30T15:08:22.697" Score="9" ViewCount="1722" Body="&lt;p&gt;I have a mainly a hydro-geological and geo-statistical background, I would like to have a basic introduction to meteorological, climatic processes and modelling techniques related to these fields. Any good resources?&lt;/p&gt;&#xA;" OwnerUserId="325" LastActivityDate="2014-05-01T12:33:29.143" Title="A good book or source for climate science and meteorology basics?" Tags="|meteorology|climate|modelling|" AnswerCount="3" CommentCount="1" CommunityOwnedDate="2014-04-30T19:46:40.630" ContentLicense="CC BY-SA 3.0" />
  <row Id="622" PostTypeId="2" ParentId="621" CreationDate="2014-04-30T15:16:59.097" Score="2" Body="&lt;p&gt;The basic meteorology book from my bookshelf would be &quot;Meteorology for Scientists and Engineers&quot; from Roland B. Stull, or his more recent but not completely finished work &lt;a href=&quot;http://www.eos.ubc.ca/books/Practical_Meteorology/&quot; rel=&quot;nofollow&quot;&gt;Practical Meteorology: An Algebra-based Survey of Atmospheric Science&lt;/a&gt;. But this is of course subjective and there will be plenty alternatives.&lt;/p&gt;&#xA;" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2014-05-01T12:33:29.143" LastActivityDate="2014-05-01T12:33:29.143" CommentCount="0" CommunityOwnedDate="2014-04-30T19:46:40.630" ContentLicense="CC BY-SA 3.0" />
  <row Id="623" PostTypeId="2" ParentId="291" CreationDate="2014-04-30T15:22:21.837" Score="4" Body="&lt;p&gt;The best I have been able to turn up is &lt;a href=&quot;http://www.brgm.eu/content/digital-data-products&quot; rel=&quot;nofollow&quot;&gt;the paid BD-logs service&lt;/a&gt;, which provides standardised lithology for borehole data. &lt;a href=&quot;http://www.opengeospatial.org/&quot; rel=&quot;nofollow&quot;&gt;Open Geospatial Consortium&lt;/a&gt; data all appears to be listed on &lt;a href=&quot;http://infoterre.brgm.fr/geoservices-ogc&quot; rel=&quot;nofollow&quot;&gt;the Geoservices page&lt;/a&gt;, and does not appear to include a lithological database/lexicon. The &lt;a href=&quot;http://www.brgm.eu/content/french-geological-reference-platform&quot; rel=&quot;nofollow&quot;&gt;French Geological Reference Platform&lt;/a&gt; does not appear to include a standalone database. The BRGM's &lt;a href=&quot;http://www.brgm.eu/content/list-websites&quot; rel=&quot;nofollow&quot;&gt;list of resources&lt;/a&gt; also does not appear to provide pointers to any relevant information. Given that the FRGM is &lt;a href=&quot;http://www.brgm.eu/content/alsace-inaugurates-pilot-french-geological-reference-platform-rgf&quot; rel=&quot;nofollow&quot;&gt;in active development&lt;/a&gt;, it seems plausible that this is not in fact a dataset that currently exists.&lt;/p&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-04-30T15:22:21.837" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="624" PostTypeId="2" ParentId="128" CreationDate="2014-04-30T16:02:31.433" Score="6" Body="&lt;p&gt;&lt;a href=&quot;http://adsabs.harvard.edu/full/1993LPI....24.1419T&quot; rel=&quot;noreferrer&quot;&gt;Therriault &lt;em&gt;et al.&lt;/em&gt; (1993)&lt;/a&gt; suggest an initial diameter of 192-300km. &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1111/j.1945-5100.1998.tb01652.x/pdf&quot; rel=&quot;noreferrer&quot;&gt;Turtle &amp;amp; Piarazzo (1998)&lt;/a&gt; suggest a smaller initial diameter but make no estimates of the depth; they do, however, suggest an impactor of 10-14km diameter. &lt;a href=&quot;http://www.jstor.org/discover/10.2307/30056197?uid=3738032&amp;amp;uid=2&amp;amp;uid=4&amp;amp;sid=21103945625027&quot; rel=&quot;noreferrer&quot;&gt;Dietz (1961)&lt;/a&gt; describes the impact crater as &quot;40km across and 16km deep&quot; - i.e. does not take into account the extensive erosion that has occurred in this location. &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1111/j.1945-5100.2008.tb01086.x/abstract&quot; rel=&quot;noreferrer&quot;&gt;Grieve &lt;em&gt;et al.&lt;/em&gt; (2008)&lt;/a&gt; also give no estimate of transient depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Numerical modelling of the impact diameter-crater depth relationship has been carried out: see e.g. &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0032063303001211&quot; rel=&quot;noreferrer&quot;&gt;W&amp;uuml;nneman &amp;amp; Ivanov (2003)&lt;/a&gt;, which also discusses crater morphology; meanwhile &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1111/j.1945-5100.2003.tb00265.x/pdf&quot; rel=&quot;noreferrer&quot;&gt;Turtle &lt;em&gt;et al.&lt;/em&gt; (2003)&lt;/a&gt; suggest that for an impactor of 10km diameter the maximum transient crater depth will be 24km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems likely that difficulty in estimating transient depth arises due to the 2Ga history of erosion in the area; as such the best option is probably to appeal to &lt;a href=&quot;https://en.wikipedia.org/wiki/Uniformitarianism_%28science%29&quot; rel=&quot;noreferrer&quot;&gt;uniformitarianism&lt;/a&gt;, and assume that the Vredefort-forming impact obeyed the same diameter-depth relationship as has been modelled for the population of recent craters in works cited above.&lt;/p&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-04-30T16:02:31.433" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="625" PostTypeId="2" ParentId="621" CreationDate="2014-04-30T16:22:17.077" Score="3" Body="&lt;p&gt;&lt;a href=&quot;http://www.esc.cam.ac.uk/library/research-skills/reading-lists/idp2&quot; rel=&quot;nofollow&quot;&gt;Cambridge University Earth Sciences Department's reading list&lt;/a&gt; particularly suggests:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Pierrehumbert, R.T. (2012), &lt;em&gt;Principles of Planetary Climate&lt;/em&gt;. Cambridge University Press, Cambridge UK, ISBN:9780521865562.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.ipcc.ch/&quot; rel=&quot;nofollow&quot;&gt;IPPC assessment reports&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Cronin, T.M., 2010. &lt;em&gt;Paleoclimates: Understanding Climate Change Past and Present&lt;/em&gt;. Columbia University Press, ISBN 978-0-231-14494-0&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;... plus many others, with a range of focuses, all of which are made explicit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other books include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Physics of the Climate System, Peixoto and Oort&lt;/li&gt;&#xA;&lt;li&gt;An introduction to dynamic meteorology, James Holton&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="105" LastEditorUserId="6" LastEditDate="2014-04-30T19:47:53.190" LastActivityDate="2014-04-30T19:47:53.190" CommentCount="4" CommunityOwnedDate="2014-04-30T19:46:40.630" ContentLicense="CC BY-SA 3.0" />
  <row Id="627" PostTypeId="1" AcceptedAnswerId="664" CreationDate="2014-04-30T16:56:36.200" Score="5" ViewCount="2669" Body="&lt;p&gt;Increasingly confused by all the &quot;spheres&quot; and agreed relationships between them. As a result, I am looking for a singular answer that clearly states at the very least what the top-level and secondary domains of Earth Science are and if possible, the domains relationships. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Spheres I have run across include, but are not limited to:&lt;/strong&gt; biosphere, atmosphere, pedosphere, lithosphere, hydrosphere, geosphere, cryosphere, exosphere, and more.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Diagram Request:&lt;/strong&gt; While not required, a visual, such as a venn diagram would likely be of use.&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="284" LastEditDate="2014-04-30T22:18:06.780" LastActivityDate="2019-02-16T16:10:21.990" Title="What are the domains of Earth Science?" Tags="|models|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="628" PostTypeId="2" ParentId="245" CreationDate="2014-04-30T17:30:08.463" Score="14" Body="&lt;p&gt;&lt;a href=&quot;http://eaps4.mit.edu/research/Lorenz/Butterfly_1972.pdf&quot;&gt;&lt;em&gt;Predictability: Does the flap of a butterfly's wings in Brazil set off a tornado in Texas?&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That was the title of Edward Lorenz's invited talk at the 139th meeting of the American Association of the Advancement of Science held in 1972. This is the origin of the term &quot;butterfly effect&quot;. The catchy title suggests that the answer must be &quot;Yes!&quot; Why else ask that question? The bulk of the talk says the answer is &quot;Nobody knows.&quot; &quot;Nobody knows&quot; doesn't jibe well with a sensationalistic, unscientific press. That a butterfly in Brazil &lt;em&gt;might&lt;/em&gt; trigger a tornado in Texas does. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lorenz had discovered in 1961 that early 1960s weather simulations were incredibly sensitive to initial conditions. Did this mean the weather itself is incredibly sensitive to minute changes? That the answer to this question is also &quot;yes&quot; marked a very important discovery. Weather and climate are the quintessential chaotic systems. Lorenz's work marked the start of modern chaos theory. His seminal 1963 paper, &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0469%281963%29020%3C0130%3ADNF%3E2.0.CO%3B2&quot;&gt;&lt;em&gt;Deterministic nonperiodic flow&lt;/em&gt;&lt;/a&gt;, has been cited 13479 times, per Google scholar. (In comparison, his 1972 talk has &quot;only&quot; been cited 345 times.) The vast majority of those 13479 citations came after his 1972 AAAS talk. Sometimes it takes a catchy title to catch the attention of a scientist.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Taking Lorenz's talk literally, asking whether a flap of a butterfly's wings in Brazil truly can set off a tornado in Texas, misses the point of his talk and of his work. The key point is that weather is chaotic. The accuracy of a detailed weather forecast fourteen days from now is rather low because that two week interval is well beyond the relevant Lyapunov timescale for such detailed predictions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What about that butterfly? It's wing flap is a very small perturbation. It's rather difficult to say that that flap caused anything of significance to happen because the relevant timescale for such infinitesimally small perturbations is very short. &lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2014-05-05T06:01:53.150" LastActivityDate="2014-05-05T06:01:53.150" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="629" PostTypeId="1" CreationDate="2014-04-30T18:53:05.220" Score="11" ViewCount="370" Body="&lt;p&gt;Human-caused global warming has had an increasingly significant effect on the earth since the industrial era began.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the beginning of the industrial era, has there been a significant increase in any of the following categories per year?&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Hurricanes&lt;/li&gt;&#xA;&lt;li&gt;Tornadoes&lt;/li&gt;&#xA;&lt;li&gt;Floods&lt;/li&gt;&#xA;&lt;li&gt;Forest fires&lt;/li&gt;&#xA;&lt;li&gt;Extreme blizzards.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Although unrelated to global warming, I am also interested in statistics on earthquakes in the same time period as a 'base case' to account for higher reporting rates.&lt;/p&gt;&#xA;" OwnerUserId="60" LastEditorUserId="60" LastEditDate="2014-05-01T12:08:47.170" LastActivityDate="2015-04-02T01:35:20.533" Title="Has the number of natural disasters per year increased significantly in the years since human-caused climate change started?" Tags="|global-warming|statistics|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="630" PostTypeId="1" AcceptedAnswerId="655" CreationDate="2014-04-30T19:26:32.337" Score="13" ViewCount="480" Body="&lt;p&gt;We do know that complex hydrocarbons (e.g., tholins) exist in the outer Solar System. Some geologists maintain that at least some oil on Earth is of non-biological origin. The mainstream, though, tends to discount their views. Is it possible to verify the hypothesis empirically and what should we look for in geodata to have it substantiated or disproven?&lt;/p&gt;&#xA;" OwnerUserId="269" LastEditorDisplayName="user20559" LastEditDate="2021-06-24T11:28:23.937" LastActivityDate="2021-07-05T04:02:49.453" Title="How can the 'abiogenic oil' hypothesis be disproven?" Tags="|geology|petroleum|geobiology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="631" PostTypeId="2" ParentId="629" CreationDate="2014-04-30T19:31:04.923" Score="9" Body="&lt;p&gt;We have no evidence to suggest that the rate or magnitude of earthquakes has, in general, increased: while earthquakes are having a greater effect on humans, this is entirely - as best we can tell - due to increased population density, and the propensity of people to build cities immediately above major fault planes (because they channel water to the surface along impermeable fault debris). Populations settling above the surface expressions of major faults isn't much of an issue when you're living in tents in a sparse community, but once you get high-density populations living in skyscrapers with poorly-enforced building regulations death and injury rates rise very rapidly. For more detail and onward references &lt;a href=&quot;http://earthquake.usgs.gov/learn/topics/increase_in_earthquakes.php&quot;&gt;see the USGS FAQ on this topic&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For statistics on extreme weather phenomena/natural disasters, particularly relating to precipitation and flooding, &lt;a href=&quot;http://ipcc.ch/&quot;&gt;the IPCC&lt;/a&gt; is an excellent resource. There is of course some degree of difficulty with reporting bias (as with earthquakes), but the IPCC are extremely rigorous in calculating - and providing - bounds on probabilities and certainties. In particular, see &lt;a href=&quot;http://ipcc-wg2.gov/AR5/&quot;&gt;Working Group 2: Impacts, Adaptation, and Vulnerability&lt;/a&gt;; their &lt;a href=&quot;http://ipcc-wg2.gov/AR5/images/uploads/IPCC_WG2AR5_SPM_Approved.pdf&quot;&gt;summary for policy-makers&lt;/a&gt; has to say:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Impacts from recent climate-related extremes, such as heat waves, droughts, floods, cyclones, and wildfires, reveal significant vulnerability and exposure of some ecosystems and many human systems to current climate variability (&lt;em&gt;very high confidence&lt;/em&gt;).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;For more details, see &lt;a href=&quot;http://ipcc-wg2.gov/AR5/report/final-drafts/&quot;&gt;the final draft of WG2's contribution to the Fifth Assessment Report (AR5)&lt;/a&gt;. Particularly worthy of highlight are &lt;a href=&quot;http://ipcc-wg2.gov/AR5/images/uploads/WGIIAR5-Volume-FAQs_FGD.pdf&quot;&gt;the FAQ&lt;/a&gt; and &lt;a href=&quot;http://ipcc-wg2.gov/AR5/images/uploads/WGIIAR5-Chap18_FGDall.pdf&quot;&gt;chapter 18.4.3&lt;/a&gt;, which has to say:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The last several decades have seen changes in the frequency and intensity of extreme weather events including extreme temperature, droughts, heavy rainfall, and tropical and extratropical cyclones with &lt;em&gt;low&lt;/em&gt; to &lt;em&gt;very high confidence&lt;/em&gt;, depending on the type of extreme event (IPCC, 2012, WGI AR5 Chapter 2). However, the impacts of extreme weather events also depend on the vulnerability and exposure of systems. It is possible that climate change can affect vulnerability and exposure, but typically both are primarily influenced by non-climate confounders, most notably economic development.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="105" LastEditorUserId="105" LastEditDate="2014-04-30T19:48:12.087" LastActivityDate="2014-04-30T19:48:12.087" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="632" PostTypeId="1" AcceptedAnswerId="634" CreationDate="2014-04-30T19:52:33.853" Score="4" ViewCount="243" Body="&lt;p&gt;Guessing that the Earth's magnetic field is the furthest observable Earth Science related phenomenon from Earth itself, though not completely sure. &lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="284" LastEditDate="2014-05-01T17:42:38.887" LastActivityDate="2014-05-01T17:42:38.887" Title="What is the furthest observable phenomenon from Earth that is Earth Science?" Tags="|geomagnetism|moon|" AnswerCount="1" CommentCount="15" ContentLicense="CC BY-SA 3.0" />
  <row Id="633" PostTypeId="2" ParentId="620" CreationDate="2014-04-30T20:03:51.927" Score="8" Body="&lt;p&gt;I normally use &lt;a href=&quot;http://scholar.google.com/&quot;&gt;Google Scholar&lt;/a&gt;, but Elsevier also has the non-public &lt;a href=&quot;http://www.scopus.com/&quot;&gt;Scopus&lt;/a&gt; (which means I have to use a campus proxy). Also &lt;a href=&quot;http://citeseerx.ist.psu.edu/&quot;&gt;CiteSeerX&lt;/a&gt; but the semantic side is not as rich.&lt;/p&gt;&#xA;" OwnerUserId="48" LastEditorUserId="48" LastEditDate="2014-04-30T21:19:08.797" LastActivityDate="2014-04-30T21:19:08.797" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="634" PostTypeId="2" ParentId="632" CreationDate="2014-04-30T20:15:44.727" Score="3" Body="&lt;p&gt;It appears the &lt;strong&gt;Earth's &lt;a href=&quot;http://en.wikipedia.org/wiki/Magnetosphere#Magnetotail&quot; rel=&quot;nofollow noreferrer&quot;&gt;magnetotail&lt;/a&gt;&lt;/strong&gt;, which is a part of its &lt;strong&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Magnetosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;magnetosphere&lt;/a&gt;&lt;/strong&gt;, is on the Earth's nightside; lengthwise exceeds 6,300,000 kilometers (3,900,000 miles); and is the furthest known observable feature of Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am unable to explain why is it commonly not included in the &quot;spheres&quot; of Earth Science.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/CwcSD.jpg&quot; alt=&quot;Diagram of Earth&amp;#39;s magnetosphere, indicating direction of solar wind and highlighting the bow shock, magnetosheath, magnetopause, polar cusp, plasmasphere, plasma mantle, magnetotail lobes, plasma sheet, and neutral point.&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Note:&lt;/strong&gt; &lt;em&gt;The gravitational pull of Earth in theory spans the known Universe, though it's unlikely to have any observable affect, unlike the Earth's magnetotail.&lt;/em&gt; &lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="105" LastEditDate="2014-04-30T20:50:48.943" LastActivityDate="2014-04-30T20:50:48.943" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="635" PostTypeId="5" CreationDate="2014-04-30T20:22:29.290" Score="0" Body="&lt;p&gt;Hydrofluoric acid is the aqueous form of the compound HF (hydrogen fluoride). HF is generated by some fluorine-rich volcanic eruptions, and the acid form is commonly used in digesting rock samples for subsequent analysis e.g. by mass spectrometry, as it is extremely efficient at breaking down silica.&lt;/p&gt;&#xA;" OwnerUserId="105" LastEditorUserId="105" LastEditDate="2014-04-30T22:50:22.697" LastActivityDate="2014-04-30T22:50:22.697" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="636" PostTypeId="4" CreationDate="2014-04-30T20:22:29.290" Score="0" Body="Questions relating to hydrofluoric acid, for example its generation in nature or its use in lab contexts such as rock digestion." OwnerUserId="105" LastEditorUserId="105" LastEditDate="2014-04-30T20:37:29.300" LastActivityDate="2014-04-30T20:37:29.300" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="637" PostTypeId="2" ParentId="621" CreationDate="2014-04-30T20:24:37.367" Score="3" Body="&lt;p&gt;I like Roland Stull's book very much.  I also like the text by Steve Ackerman and John Knox, &lt;em&gt;Meteorology:  Understanding the Atmosphere&lt;/em&gt;.  Both of these are quite informative.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Historically, the book I think I like the best is the one by James Edinger, et al., if you can find it - &lt;em&gt;Understanding our Atmospheric Environment&lt;/em&gt;, by a team of faculty from UCLA in the 1970s.  It still has a great pedagogic structure to it and plenty of mathematical structure appropriate for scientists from other quantitative backgrounds who have a need for more depth.  It of course lacks the details that are needed to understand the climate system based on the last 40 years of important climate research, atmospheric chemistry, and mesoscale systems - someone needs to write that book with some calculus.  Roland's book may come closest.  &lt;/p&gt;&#xA;" OwnerUserId="333" LastActivityDate="2014-04-30T20:24:37.367" CommentCount="0" CommunityOwnedDate="2014-04-30T20:24:37.367" ContentLicense="CC BY-SA 3.0" />
  <row Id="638" PostTypeId="2" ParentId="609" CreationDate="2014-04-30T20:28:35.590" Score="8" Body="&lt;p&gt;&lt;strong&gt;Terminology&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The term &quot;average&quot; isn't a specific term.  Are you talking daily average or annual average?  The question &quot;What is the average?&quot; begs the question of &quot;Across what timeframe?&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To explain that point, let's look at a chart:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/QpHLK.gif&quot; alt=&quot;Groundwater depletion&quot;&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the groundwater level of a well in Georgia (US).  The &quot;Average&quot; for this well in December 2003 would be 176.9 feet below ground level.  However, for the year 2003 altogether, it would be around 177 feet below ground level.  For the previous decade, the average would be around 175 below ground level. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Timeframe&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer the question, the best timeframe is the largest timeframe you can afford to gather.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we look at the &lt;a href=&quot;https://water.usgs.gov/edu/gwdepletionchart.html&quot; rel=&quot;noreferrer&quot;&gt;Raw data for the above chart&lt;/a&gt;, what we see is that for the year 2003, the groundwater levels went &lt;em&gt;up&lt;/em&gt;!  If you only gather one year of data, this well would show a dramatic rise in water levels, which would clearly not be accurate.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you extended the search back five years, you would see a large downward trend.  March 1998 shows 173 feet depth and March 2003 shows 178 feet depth.  This trend indicates a dramatic loss of water volume.  However, without a larger timeframe, it's impossible to tell if this is just a negative trend or a cyclical one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even in the chart above, the mid-1960s may just have been a high point in the water table.  (Indeed, Georgia saw 15% more percipitation in 1967 than is historically average and 1999-2001 were historically low.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Summary&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The best timeframe to gather data is the longest timeframe that you can get.  &lt;/p&gt;&#xA;" OwnerUserId="330" LastActivityDate="2014-04-30T20:28:35.590" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="639" PostTypeId="5" CreationDate="2014-04-30T20:34:43.770" Score="0" Body="&lt;p&gt;Crystallography is the study of the arrangement of atoms in solids. &lt;a href=&quot;http://www.webmineral.com/crystall.shtml#.U2FdGdCQnRY&quot; rel=&quot;nofollow&quot;&gt;Details of the 32 crystal classes are available from WebMineral&lt;/a&gt;. X-ray Diffraction is the classic technique employed in studying crystal form, but the crystal class to which a mineral belongs may determine its shape on the macro scale in addition to its optical properties, e.g. appearance under cross-polarised light, and other material properties. Questions relating to the influence of crystal structure on mineral properties can use this tag, as can discussion of analytical techniques.&lt;/p&gt;&#xA;" OwnerUserId="105" LastEditorUserId="105" LastEditDate="2014-04-30T22:49:46.583" LastActivityDate="2014-04-30T22:49:46.583" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="640" PostTypeId="4" CreationDate="2014-04-30T20:34:43.770" Score="0" Body="questions relating to the arrangement of atoms in solids, such as the ways in which crystal structure influence material properties, or suitable analytical methods e.g. X-ray diffraction and microscopy" OwnerUserId="105" LastEditorUserId="105" LastEditDate="2014-04-30T22:50:14.963" LastActivityDate="2014-04-30T22:50:14.963" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="641" PostTypeId="5" CreationDate="2014-04-30T20:36:29.840" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-30T20:36:29.840" LastActivityDate="2014-04-30T20:36:29.840" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="642" PostTypeId="4" CreationDate="2014-04-30T20:36:29.840" Score="0" Body="concerned with the formation of deserts (areas receiving very little precipitation) and processes occurring specifically within deserts" OwnerUserId="105" LastEditorUserId="105" LastEditDate="2014-04-30T22:49:54.287" LastActivityDate="2014-04-30T22:49:54.287" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="643" PostTypeId="1" AcceptedAnswerId="652" CreationDate="2014-04-30T20:49:24.193" Score="18" ViewCount="38508" Body="&lt;p&gt;Why does earth rotate in a clockwise direction?  Did a large meteor collide with earth causing earth to rotate?  If that is what happened, could another, larger meteor cause earth to reverse its rotation?&lt;/p&gt;&#xA;" OwnerUserId="181" LastEditorUserId="64" LastEditDate="2014-11-19T15:08:47.847" LastActivityDate="2017-09-26T13:52:13.330" Title="Why does the earth spin clockwise?" Tags="|earth-history|planetary-science|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="644" PostTypeId="5" CreationDate="2014-04-30T20:56:25.950" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-30T20:56:25.950" LastActivityDate="2014-04-30T20:56:25.950" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="645" PostTypeId="4" CreationDate="2014-04-30T20:56:25.950" Score="0" Body="Concerning the processes by which living organisms produce minerals, in addition to questions about types of mineral and advantages/disadvantages of so doing." OwnerUserId="105" LastEditorUserId="105" LastEditDate="2014-04-30T21:22:01.147" LastActivityDate="2014-04-30T21:22:01.147" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="646" PostTypeId="5" CreationDate="2014-04-30T20:59:50.350" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-30T20:59:50.350" LastActivityDate="2014-04-30T20:59:50.350" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="647" PostTypeId="4" CreationDate="2014-04-30T20:59:50.350" Score="0" Body="concerning rocks and processes relating to the cooling and solidification of magma, typically involving temperatures above approximately 800 degrees Celsius for at least some of the rock's history" OwnerUserId="105" LastEditorUserId="105" LastEditDate="2014-04-30T22:50:05.903" LastActivityDate="2014-04-30T22:50:05.903" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="648" PostTypeId="5" CreationDate="2014-04-30T21:17:38.677" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-04-30T21:17:38.677" LastActivityDate="2014-04-30T21:17:38.677" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="649" PostTypeId="4" CreationDate="2014-04-30T21:17:38.677" Score="0" Body="Concerning the dynamics and chemistry of convectively upwelling plumes in the mantle, including questions relating evidence base, definition and controversies." OwnerUserId="105" LastEditorUserId="20" LastEditDate="2014-04-30T21:22:44.623" LastActivityDate="2014-04-30T21:22:44.623" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="650" PostTypeId="2" ParentId="643" CreationDate="2014-04-30T21:29:45.520" Score="14" Body="&lt;p&gt;If you ascribe to the giant impact hypothesis, which most scientists do, whatever rotation the Earth had prior to the formation of the Moon was lost thanks to that 'giant impact'. That was a massive impact involving a Mars-sized body colliding with the proto-Earth. A &quot;little&quot; impact wouldn't change the Earth's rotation by much at all. Note very well: Something that could entirely wipe out life as we know it would still be &quot;little&quot; in this regard. Another big oblique whack by a Mars-sized body would be needed to make a sizable dent in the Earth's rotation axis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you look at the &lt;strike&gt;nine&lt;/strike&gt; eight planets, it's only Jupiter that reliably retains its primordial rotation. Whatever rotation rate / rotation axis Mercury and Venus had in the distant past has been wiped out thanks to tidal interactions between those planets, the Sun, and Jupiter (a.k.a. the 600 pound gorilla). Mars' rotation is notoriously chaotic. Uranus has been tilted by ~90 degrees by something, either a big whack or (once again) tidal interactions. Neptune and Saturn have obliquities of about 30 degrees. Those deviations may be a result of tidal interactions, or maybe of a lesser whack. Scientists don't know. There are lots of different hypotheses, but all have problems and none has taken hold yet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth? Whatever formed the Moon, whether by giant impact or something else, it almost certainly wreaked havoc with the Earth's primordial rotation.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="115" LastEditDate="2014-05-01T14:45:07.390" LastActivityDate="2014-05-01T14:45:07.390" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="651" PostTypeId="1" AcceptedAnswerId="654" CreationDate="2014-04-30T21:30:48.177" Score="8" ViewCount="2452" Body="&lt;p&gt;Why is the axis of earth tilted?  It can't possibly be that the Northern hemisphere is larger causing it to be pulled toward the sun, because then it would always be summer in the N hemisphere and winter in the S hemisphere.  If the cause for the tilt is because a large space object collided with earth offsetting the axis, then wouldn't earth keep moving in the direction of the collision?  Any insite would be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="181" LastEditorUserId="64" LastEditDate="2014-11-19T15:08:36.133" LastActivityDate="2014-11-19T15:08:36.133" Title="Why is earth's axis tilted?" Tags="|earth-history|planetary-science|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="652" PostTypeId="2" ParentId="643" CreationDate="2014-04-30T21:35:28.060" Score="14" Body="&lt;h2&gt;Earth's Spin&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Earth rotating clockwise is the &lt;a href=&quot;http://scienceblogs.com/startswithabang/2010/10/07/counterclockwise-but-there-are/&quot; rel=&quot;noreferrer&quot;&gt;result of a chain reaction that started when Earth's star formed&lt;/a&gt; as the result gas clouds collapsing. During the collapse of the gas, one direction was shorter and a disc formed. Due to the &lt;a href=&quot;http://en.wikipedia.org/wiki/Angular_momentum&quot; rel=&quot;noreferrer&quot;&gt;law of conservation of angular momentum&lt;/a&gt;, the disc gained an overall spin, which was passed to all the objects of notable mass within its solar system; these objects are commonly known as planets. As a result, all planets within a given solar system have the same spin as the star in it to start. That said, the axis of a planet may do a 180-degree flip on its axis at some point, and if this happens, like Venus, it would spin counter to its native spin; in fact, in the case of Earth, it appears given there appears to be &lt;a href=&quot;http://www.universetoday.com/558/did-the-earth-flip-over-in-the-past/&quot; rel=&quot;noreferrer&quot;&gt;evidence that it's has flipped in the past&lt;/a&gt;, that the Earth's axis has already flipped at least twice, since it's current back in sync with the Sun's spin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Might be worth noting that all rotating bodies that rotate clockwise when viewed from the southern hemisphere rotate and counter-clockwise when viewed from the northern hemisphere. Also, since the Sun is not solid on the surface, it does not rotate as a solid body; meaning it rotates faster at its equator and slower at its poles.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Earth's Axis&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;As for the reasoning behind, the axis of the rotation, as pointed out in other answers, this is the result of Earth's past impacts with objects of enough mass to produce the shift from a zero offset from the stars axis, to the current axis of the rotation. Future impacts would be able to change the rotation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Will the Earth's axis flip?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;http://www.universetoday.com/558/did-the-earth-flip-over-in-the-past/&quot; rel=&quot;noreferrer&quot;&gt;Scientists have found evidence&lt;/a&gt; that the Earth might have flipped over&#xA;  in the past, completely shifting the orientation of its poles. The&#xA;  theory has been around for years; that a large mountain range or&#xA;  supervolcano might unbalance the spinning Earth. Over the course of&#xA;  millions of years, the Earth would change the orientation of its axis&#xA;  until the object was balanced at the equator again.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Current Axis of the Planets in Earth's solar system&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/V2ZZY.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="4636" LastEditDate="2016-05-06T21:41:04.200" LastActivityDate="2016-05-06T21:41:04.200" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="653" PostTypeId="2" ParentId="563" CreationDate="2014-04-30T21:40:56.773" Score="11" Body="&lt;p&gt;Per &lt;a href=&quot;http://what-if.xkcd.com/94/&quot;&gt;yesterday's What-If&lt;/a&gt;,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If you make a building too big, the top part is heavy and it squishes the bottom part.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In the context of Tibet, what this means is that rock has a yield strength: pile it up high enough and it will break (via earthquakes); and if you make a big enough pile, especially of continental material, then the concentrations of radiogenic isotopes will be high enough to significantly raise the temperature - and lower the strength - of the rock in question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case of Tibet and the Himalaya, height &lt;em&gt;increase&lt;/em&gt; is due to north-south shortening as the Indian plate impacts the Eurasian plate, i.e. the Tibetan plateau initially formed via exactly the same process as the Himalaya. In order to get an approximately stable height, this increase has to be balanced by &lt;em&gt;decrease&lt;/em&gt;. The principle processes causing decrease in height in Tibet are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;east-west extension (see. e.g. &lt;a href=&quot;http://rsta.royalsocietypublishing.org/content/327/1594/379.short&quot;&gt;Dewey &lt;em&gt;et al.&lt;/em&gt; (1988)&lt;/a&gt;, &lt;a href=&quot;http://sp.lyellcollection.org/content/19/1/113.short&quot;&gt;Tapponnier &lt;em&gt;et al.&lt;/em&gt; (1986)&lt;/a&gt;), typically along strike-slip faults: this is clearly visible not only in &lt;a href=&quot;http://www.geo.arizona.edu/~ozacar/tecton~1.htm&quot;&gt;geological maps&lt;/a&gt; but also in aerial/satellite photography&lt;/li&gt;&#xA;&lt;li&gt;erosion rates increase as topography becomes higher, especially in areas of active mountain-building, in part through &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0012821X02007252&quot;&gt;a change in which erosion processes are favoured&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;That the Tibetan plateau is of such uniform height corresponds neatly to calculations suggesting that this is the maximum possible height for such features if they are of typical crustal composition.&lt;/p&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-04-30T21:40:56.773" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="654" PostTypeId="2" ParentId="651" CreationDate="2014-04-30T21:56:21.247" Score="8" Body="&lt;p&gt;The simple answer: Because it is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's a nice theory that explains why the rotation axis of a big gas giant is more or less coaligned with its orbital angular momentum vector. Those big gas giants form somewhat like a snowball rolling downhill becomes bigger and bigger and bigger. This doesn't apply to rocky planets, let alone lesser gas giants and ice giants. Saturn's rotation axis is inclined by 27°, Uranus by 98°, Neptune by 30°. It's a bit random.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regard to the rocky planets, whatever rotation Mercury had in the distant past is long lost. Tidal interactions with the Sun will necessarily have locked Mercury into a resonance between rotation and orbital rotations. That the resonance is 3:2 rather than 1:1 is a result of the largish eccentricity of Mercury's orbit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mars is not tidally locked, but it's obliquity is notoriously chaotic. A number of past and future recreations of Mars' rotation show chaotic behavior. Whatever rotation Mars had when it formed has long been lost thanks to that chaos. The obliquity of Mars has gone through huge changes over the last few billion years, occasionally changing rapidly, occasionally remaining stable. That's the nature of chaos.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Venus also isn't tidally locked &lt;em&gt;per se&lt;/em&gt;, but essentially it is. The rotation of Venus is rather bizarre. The solid part of the planet rotates retrograde at a very slow rate. On the other hand, the upper parts of Venus' thick atmosphere rotate prograde. The combined rotation represents one of the four final states in which Venus as a whole can rotate (multiple articles by Laskar, and by others). Venys is in its final rotational state.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth is a marked exception amongst the rocky planets. The key to that marked exception is our exceptionally massive moon. The Earth's moon acts to stabilize the Earth's rotation. Whatever obliquity the proto-Earth had prior to the giant impact is long lost. On the other hand, the obliquity after that giant impact has remained fairly constant thanks to that stabilizing influence.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-04-30T21:56:21.247" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="655" PostTypeId="2" ParentId="630" CreationDate="2014-04-30T22:15:11.670" Score="10" Body="&lt;p&gt;One possible key is isotopic fractionation via biological processes - see &lt;a href=&quot;https://en.wikipedia.org/wiki/C4_carbon_fixation#The_evolution_and_advantages_of_the_C4_pathway&quot;&gt;dating the development of the C&lt;sub&gt;4&lt;/sub&gt; photosynthetic pathway&lt;/a&gt;, and specifically &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1626541/&quot;&gt;isotopic fractionation between carbon-13 and carbon-14&lt;/a&gt;. &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C from volcanic degassing is markedly different to that from biological sources; the arguments for human involvement in climate change (see e.g. &lt;a href=&quot;http://ipcc.ch&quot;&gt;the IPCC&lt;/a&gt;) rely on the changes in &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C since the beginning of the Industrial Revolution: the value has shifted markedly towards that of the hydrocarbons we've been burning from its pre-Industrial value. (As for how we know atmospheric &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C for CO&lt;sub&gt;2&lt;/sub&gt; prior to the Industrial Revolution - the answer is polar ice cores!)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus the arguments for/against abiogenic oil rest on (1) isotopic ratios, and (2) other geochemical indicator ratios; see e.g. &lt;a href=&quot;http://www.osti.gov/scitech/biblio/7052010&quot;&gt;Jenden &lt;em&gt;et al.&lt;/em&gt; (1993)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0264817210001224&quot;&gt;H&amp;ouml;&amp;ouml;k &lt;em&gt;et al.&lt;/em&gt; (2010)&lt;/a&gt;, in a review of the arguments for biogenic and abiogenic formation processes, say:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;However, theoretical studies, laboratory verification and discoveries of trace amounts of abiotic oil do not imply the existence of commercially significant deposits. [...] The lack of a clear and irrefutable success in locating abiotic petroleum in commercial quantities is problematic.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This year, &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0146638013002891&quot;&gt;Ahmed &lt;em&gt;et al.&lt;/em&gt; (2014)&lt;/a&gt; advances the argument that Siljan Crater oil is unambiguously of biogenic origin due to the copresence of molecules of &quot;known&quot; organic origin (specifically terpane and sterane biomarkers). As for a definitive answer, [Wang &lt;em&gt;et al.&lt;/em&gt; (2014)&lt;a href=&quot;http://link.springer.com/article/10.1007/s11430-014-4821-8&quot;&gt;7&lt;/a&gt; say:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Whether abiotic (inorganic) process can form oil and gas resource is a difficult question that has been explored continuously by scientific community for more than a century but has not yet been solved.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-04-30T22:15:11.670" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="656" PostTypeId="2" ParentId="651" CreationDate="2014-04-30T22:15:20.020" Score="5" Body="&lt;h2&gt;Earth's Spin&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Earth rotating clockwise is the &lt;a href=&quot;http://scienceblogs.com/startswithabang/2010/10/07/counterclockwise-but-there-are/&quot; rel=&quot;nofollow noreferrer&quot;&gt;result of a chain reaction that started when Earth's star formed&lt;/a&gt; as the result gas clouds collapsing. During the collapse of the gas, one direction was shorter and a disc formed. Due to the &lt;a href=&quot;http://en.wikipedia.org/wiki/Angular_momentum&quot; rel=&quot;nofollow noreferrer&quot;&gt;law of conservation of angular momentum&lt;/a&gt;, the disc gained an overall spin, which was passed to all the objects of notable mass within its solar system; these objects are commonly known as planets. As a result, all plants within a given solar system have the same spin as the star in their solar system to start. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Might be worth noting that all rotating bodies that rotate clockwise when viewed from the southern hemisphere rotate and counter-clockwise when viewed from the northern hemisphere. Also, since the Sun is not solid on the surface, it does not rotate as a solid body; meaning it rotates faster at its equator and slower at its poles.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Earth's Axis&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;As for the reasoning behind, the axis of the rotation, as pointed out in other answers, this is the result of Earth's past impacts with objects of enough mass to produce the shift from a zero offset from the stars axis, to the current axis of the rotation. Future impacts would be able to change the rotation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Current Axis of the Planets in Earth's solar system&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/V2ZZY.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="284" LastEditDate="2014-05-01T15:49:27.367" LastActivityDate="2014-05-01T15:49:27.367" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="657" PostTypeId="2" ParentId="627" CreationDate="2014-04-30T22:20:47.650" Score="5" Body="&lt;p&gt;Originally, the image below provided a (potentially incomplete) example within the question, but appears to be more of an answer. So I've moved it from the question to here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/bHv0O.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/scitable/knowledge/library/the-soil-biota-84078125&quot; rel=&quot;noreferrer&quot;&gt;(Image Source)&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="115" LastEditDate="2014-05-01T01:52:14.600" LastActivityDate="2014-05-01T01:52:14.600" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="658" PostTypeId="2" ParentId="354" CreationDate="2014-04-30T22:37:12.977" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;How do we use the information in g(t) to determine the composition of the medium that the wave is traveling through? Moreover, knowing that the earth is heterogeneous, how can we isolate any one single substance or rock type? How accurate is this kind of measurement?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In short: we can't, and it's not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Taking the example of oceanic lithosphere, we can take a pretty good stab: we know (approximately) what a cross-section through the oceanic crust and mantle looks like because of the existence of &lt;a href=&quot;http://volcano.oregonstate.edu/education/facts/ophiolites.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ophiolites&lt;/a&gt;. They're pretty consistent in terms of thicknesses of units represented (see the cross-section at that link), so when in oceanic lithosphere we see 2km at a certain velocity underlain by 4km at a different velocity, with a sharp transition between the two, it's a fair bet that the former corresponds to sheeted dykes and the latter to layered gabbros, and so on down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some laboratory measurements of the speed of sound waves in various lithologies &lt;em&gt;can&lt;/em&gt; be made (including measurements of both synthetic substances and of mantle xenoliths that have, for whatever reason, been brought up to the surface), but they aren't definitive. Seismic anisotropy - different &quot;speeds&quot; to different components of wave phases (e.g. P versus S waves) depending on the angle the wave being measured took through the rock in question - can be linked to e.g. alignment of olivine crystals. As another example &lt;a href=&quot;https://earthscience.stackexchange.com/questions/517/how-can-we-guess-the-size-of-the-earths-inner-coreand-what-its-made-of&quot;&gt;we know that the core is of a different composition to the mantle&lt;/a&gt; because of the difference in the speed of sound and through mass-balance arguments, but seismic velocity through the core doesn't tell us anything about &lt;em&gt;what&lt;/em&gt; it's made of.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To add further complications, variations in seismic speed can always be explained by a trade-off between compositional and thermal variations, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/589/are-mantle-plumes-distributed-around-the-core-randomly-or-in-a-known-pattern/598#598&quot;&gt;as with LLSVPs&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mostly what we're working with here is a bunch of best guesses. That's not to say they're useless - in a field where you get to run a single experiment that lasts 4.5Ga and you've no control over any of the parameters, best guesses are often the best we have to work with - but they're also &lt;i&gt;very definitely&lt;/i&gt; not definitive.&lt;/p&gt;&#xA;" OwnerUserId="105" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-04-30T22:37:12.977" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="659" PostTypeId="2" ParentId="619" CreationDate="2014-04-30T23:06:44.713" Score="2" Body="&lt;p&gt;It seems to me you should draft an analytical procedure first in which you include the compounds (or compound-groups) you want to identify (qualitative) and what detection limits you need. Then get a list of methods or instruments you have access to. Then see which methods / instruments fulfil your analytical requirements. You might need to make aliquots and use two or more methods to cover all the requirements.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Complexity is usually the last thing to worry about, because you have to use what instruments you have, and often times the analytical requirements are only fulfilled by one instrument. The methods mentioned on the page you linked also guarantee that your measurements will be comparable to other peoples measurements.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Look for advice in books and lecture notes about &quot;analytical chemistry&quot; and &quot;instrumental analytics&quot;. Personally I think infrared spectroscopy is pretty simple, but I don't know what your detection limit requirements are (&quot;trace level&quot; is very vague), and depending on your samples there might be a lot of overlap from the different organics (It also depends on how well you have to distinguish them).&lt;/p&gt;&#xA;" OwnerUserId="23" LastActivityDate="2014-04-30T23:06:44.713" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="660" PostTypeId="2" ParentId="154" CreationDate="2014-04-30T23:20:38.160" Score="12" Body="&lt;p&gt;First things first about Laki: it's in Iceland, which means its source is a combination of an ocean ridge and a mantle plume. The plume contribution means that the source composition is relatively undegassed (unlike the source for most mid-ocean-ridge basalts (MORBs)!) and very basic, so contains relatively high concentrations of sulphur and other volatiles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly, it was actually a pretty high-volume eruption: per &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1111/j.1752-699X.2010.00231.x/&quot;&gt;Gudmundsson (2011)&lt;/a&gt; &lt;em&gt;it has been estimated that it produced 14 km&lt;sup&gt;3&lt;/sup&gt; of lava&lt;/em&gt; - compare with &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/0377027384900398&quot;&gt;the estimated average global rate of magma emplacement and volcanic output&lt;/a&gt; of 26-34km&lt;sup&gt;3&lt;/sup&gt; per year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://link.springer.com/article/10.1007/s004450050136#page-1&quot;&gt;eruption style&lt;/a&gt; during the Laki eruption - not dissimilar to other Icelandic eruptions - is believed to have promoted volatile emissions during the eruption, including liberating up to 50% of F originally dissolved in the melt:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The high degree of degassing at the vents is attributed to development of a separated two-phase flow in the upper magma conduit, and implies that high-discharge basaltic eruptions such as Laki are able to loft huge quantities of gas to altitudes where the resulting aerosols can reside for months or even 1–2 years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Thus the significant fluorine release at Laki seems to have been due to a large-volume eruption degassing halogens extremely efficiently, with a relatively high initial fluorine concentration in the melt (&lt;a href=&quot;http://link.springer.com/article/10.1007/s004450050136#page-1&quot;&gt;~400ppm&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="105" LastEditorUserId="105" LastEditDate="2014-05-01T11:06:17.630" LastActivityDate="2014-05-01T11:06:17.630" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="661" PostTypeId="2" ParentId="277" CreationDate="2014-04-30T23:42:53.580" Score="9" Body="&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2486.2010.02198.x/abstract&quot;&gt;Barnes &amp;amp; Hillenbrand (2010)&lt;/a&gt; argue that there is faunal evidence for a late-Quaternary trans-Antarctic seaway. From the abstract:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We investigated biological evidence for past connectivity between different regions of Antarctica by comparing the composition of modern bryozoan assemblages from the continental margin around Antarctica. Surprisingly, we found most similarity between two areas which are not currently connected – the shelves of the Weddell Sea (WS) and Ross Sea (RS). We evaluated three hypotheses to explain this and conclude that bryozoans most likely dispersed through a trans-Antarctic seaway that opened in response to a WAIS collapse and connected the WS and RS shelves. These bryozoans must have survived glaciations(s) during subsequent ice ages in refuges, whereas they were wiped out in most other regions of the Antarctic shelf. After the last glacial period, bryozoan assemblages could freely disperse between many of the regions we examined (e.g. Antarctic Peninsula and South Shetland Islands), which has allowed recolonization of areas in which bryozoans had been eradicated during the last ice age. For the bryozoans on the WS and RS shelves to be more similar than those which are in close proximity means the trans-Antarctic seaway may have been as late as the last few interglacials.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There are some other folk in agreement, in particular &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1111/j.1365-294X.2012.05572.x/full&quot;&gt;Strugnell &lt;em&gt;et al.&lt;/em&gt; (2012)&lt;/a&gt; on the topic of &lt;em&gt;genetics of an Antarctic octopus&lt;/em&gt; (yes, &lt;em&gt;really&lt;/em&gt;); and &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2011GC003688/full&quot;&gt;Vaughan &lt;em&gt;et al.&lt;/em&gt; (2011)&lt;/a&gt; review available data and find strong biogeographical evidence for the existence of such a trans-Antarctic seaway, with four possible candidates and extensive discussion of when it might most recently have been open:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The methods currently at our disposal do not allow us to constrain, with confidence, which recent interglacial saw the last open West Antarctic seaways. However, given that during the last interglacial (MIS 5e), air temperature in Antarctica was substantially warmer than present for several thousand years [Sime et al., 2009] and at the same time, ice-loss from Antarctica almost certainly contributed to higher global sea levels [Kopp et al., 2009], it would appear that MIS 5e is a strong candidate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In summary: biogeography &lt;em&gt;and octopuses&lt;/em&gt; say yes.&lt;/p&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-04-30T23:42:53.580" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="662" PostTypeId="2" ParentId="432" CreationDate="2014-04-30T23:55:10.207" Score="16" Body="&lt;p&gt;Atmospheric escape is a topic with a long research history. It is complex and is being addressed with both measurements and simulations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, the question of atmospheric escape is still actively researched at Mars, and the MAVEN (Mars Atmosphere and Volatile Evolution) spacecraft mission is for example dedicated to this topic. Mars is a planet without a significant global magnetic field (although it does possess crustal magnetic anomalies); in fact its planetary dynamo was active and then stopped about 3.6 billion years ago, which considerably reduced the strength of its magnetic field.&lt;br&gt;&#xA;So understanding the evolution of its atmosphere helps to relate to what would happen if Earth would loose its magnetic field. The question of atmospheric escape at Mars is relevant concerning the fate of water (geological evidences indicate the presence of liquid water in the past, which suggests a warm and dense atmosphere able to support it at that time).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Besides thermal atmospheric escape, there is also non thermal escape, including removal by asteroid impact (in the past) and by interaction between the atmosphere and the solar wind leading to pickup of atmospheric ions (in the past and continuing today).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some examples of references to the scientific literature about atmospheric escape at terrestrial planets (abstracts):&lt;br&gt;&#xA;&lt;a href=&quot;http://adsabs.harvard.edu/abs/2013SSRv..174..113L&quot; rel=&quot;noreferrer&quot;&gt;Outgassing History and Escape of the Martian Atmosphere and Water Inventory&lt;/a&gt;&lt;br&gt;&#xA;or&lt;br&gt;&#xA;&lt;a href=&quot;http://adsabs.harvard.edu/abs/1996RvGeo..34..483S&quot; rel=&quot;noreferrer&quot;&gt;Nonthermal escape of the atmospheres of Venus, Earth, and Mars&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="339" LastEditorUserId="595" LastEditDate="2015-04-02T14:46:45.020" LastActivityDate="2015-04-02T14:46:45.020" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="663" PostTypeId="2" ParentId="127" CreationDate="2014-05-01T00:39:51.753" Score="14" Body="&lt;p&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/0019103591900858&quot;&gt;Love &amp;amp; Brownlee (1991)&lt;/a&gt; put together numerical models for the experiences of micrometeorites entering the atmosphere. They say:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The peak temperatures experienced by submillimeter micrometeoroids rarely exceed 1700°C. Maximum temperature and mass loss rate generally occur at altitudes between 85 and 90 km during ∼1 sec of peak heating. A typical melted particle spends ∼2 sec at temperatures above the melting point.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/0019103589900912&quot;&gt;Flynn (1989)&lt;/a&gt; discusses interplanetary dust, with figures for peak temperatures given in the abstract.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I think that what you &lt;em&gt;really&lt;/em&gt; want is &lt;a href=&quot;http://www.uark.edu/depts/cosmo/publications/pub%20by%20year/1975%20papers/sears%201975b.pdf&quot;&gt;Sears (1975)&lt;/a&gt;, &lt;em&gt;Temperature gradients in meteorites produced by atmospheric passage&lt;/em&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Temperatures in the order of 200°C have usually penetrated no further than 5-10mm, which is consistent with a luminous flight time of the order of 10s.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Using the geologists' rule of thumb for timescales of cooling (I believe $\tau^2 = \ell/\kappa$, where $\tau$ is the timescale, $\ell$ is the thickness of the cooling body, and $\kappa$ is the thermal conductivity - though it's a while since I've had to do this so I may be misremembering...), the information above about the height above the surface at which peak temperature is commonly reached, and an estimate of particle velocity, you can probably back-of-envelope a temperature for a meteorite on impact!&lt;/p&gt;&#xA;" OwnerUserId="105" LastEditorUserId="67" LastEditDate="2014-05-14T03:27:38.990" LastActivityDate="2014-05-14T03:27:38.990" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="664" PostTypeId="2" ParentId="627" CreationDate="2014-05-01T01:17:31.370" Score="5" Body="&lt;p&gt;Regarding subdomains - I expect that there may be hundreds or thousands of subdomain *spheres. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, I've studied soil for many years and had never heard of the &quot;drillosphere&quot;, &quot;porosphere&quot;, &quot;aggregatusphere&quot;, or &quot;detritusphere&quot;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;“drilosphere” (the portion of the soil volume influenced by secretions&#xA;  of earthworms), the porosphere (the total pore space), detritusphere&#xA;  (dead plant and soil biota), aggregatusphere (the sum of aggregates)&#xA;  and the rhizosphere.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;from fig 4 in the &lt;a href=&quot;http://www.nature.com/scitable/knowledge/library/the-soil-biota-84078125&quot; rel=&quot;nofollow noreferrer&quot;&gt;same Nature Education article&lt;/a&gt; that provided the &lt;a href=&quot;https://earthscience.stackexchange.com/a/657/174&quot;&gt;macro-view venn diagram in @blunders' answer&lt;/a&gt;.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/qltJO.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qltJO.jpg&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sub&gt;(source: &lt;a href=&quot;http://www.nature.com/scitable/content/ne0000/ne0000/ne0000/ne0000/84078425/fig4_Finalv2_1_2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;nature.com&lt;/a&gt;)&lt;/sub&gt;  &lt;/p&gt;&#xA;" OwnerUserId="174" LastEditorUserId="2958" LastEditDate="2019-02-16T16:10:21.990" LastActivityDate="2019-02-16T16:10:21.990" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="665" PostTypeId="1" AcceptedAnswerId="667" CreationDate="2014-05-01T03:46:59.753" Score="5" ViewCount="7915" Body="&lt;p&gt;When comparing the average distance of the all known earthquake epicenters to the nearest pole, is the longitudinal distance to the equator or the poles the smallest of the two?  Please note that any period for which earthquakes were able to be tracked must have taken place globally and allowed the location of the epicenters to be be estimated in a meaningful way as it relates to the question; meaning if the location is off by 3% that's likely okay, being off by 50% would not be okay. &lt;/p&gt;&#xA;&#xA;&lt;h2&gt;&lt;a href=&quot;http://www.globalquakemodel.org/what/seismic-hazard/historical-catalogue/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Global Historical Earthquake Archive (1000-1903)&lt;/a&gt;&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/FrRW6.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/List_of_tectonic_plates&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global earthquake epicenters, 1963–1998&lt;/a&gt;&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Uravr.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="284" LastEditDate="2014-05-01T11:28:30.723" LastActivityDate="2014-05-11T14:15:05.270" Title="Are there more earthquakes near the equator or poles?" Tags="|earthquakes|earth-history|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="666" PostTypeId="2" ParentId="19" CreationDate="2014-05-01T03:56:25.257" Score="23" Body="&lt;p&gt;Weather models (or, as they are more commonly called in the field, atmospheric models) are computer programs that read in input data (initial conditions) and solve partial differential equations to produce a future state of the atmosphere. Although @JonEricson provides an overall good but anecdotal summary of what models do, here I describe the exact steps of what it takes for an atmospheric model to produce a forecast. This answer generally applies to ocean circulation and climate models as well. Many people believe that weather forecasters sit in front of a map and brainstorm where the cloud will go. This answer aims to provide an easy to understand but thorough explanation about how atmosphere and ocean prediction models work.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The evolution of the atmosphere may be described by a system of partial differential equations (PDEs). Most commonly, these are &lt;a href=&quot;http://en.wikipedia.org/wiki/Primitive_equations&quot;&gt;primitive equations&lt;/a&gt;, which consist of momentum equation (solving for velocity $\mathbf{v}$ or momentum $\mathbf{\rho v}$), continuity (or mass conservation equation) and thermal energy equation (solving for temperature $T$ and specific humidity $q$). Continuity equation is necessary for closure with the momentum equations. These equations may be approximated in many ways, yielding a reduced and/or simplified set of equations. Some of these approximations are hydrostatic, Boussinessq, anelastic etc. In the most complete form of the primitive equations for the atmosphere the prognostic state variables are $u$, $v$, $w$, $p$, $T$, $q$. An idealized atmosphere could also be simulated with just momentum and continuity equations (no thermodynamics), shallow water equations or just absolute vorticity equation. For an example of the latter, see the pioneering paper by &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1111/j.2153-3490.1950.tb00336.x/abstract&quot;&gt;Charney, Fjortoft and von Neumann (1950)&lt;/a&gt; who numerically predicted 500 mb vorticity by integrating the absolute vorticity equation in time. Because their model was barotropic it could not produce cyclogenesis. However, they achieved the first successful numerical weather prediction in history and their model ran on the first general-purpose computer, &lt;a href=&quot;http://en.wikipedia.org/wiki/Eniac&quot;&gt;ENIAC&lt;/a&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Now take the momentum equation for example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\dfrac{\partial \rho \mathbf{v}}{\partial t} + \nabla (\rho \mathbf{v}^{2}) +2\Omega \times \rho \mathbf{v} = -\nabla p + \nu \nabla^{2}(\rho \mathbf{v}) + \Phi $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From left to right, we have the time tendency of momentum, advection, Coriolis force, pressure gradient, viscous dissipation, and finally, any external forcing or subgrid tendency. Unfortunately, the advection term $\nabla(\rho\mathbf{v}^{2})$ is non-linear, and it is because of this term that the analytical solution to this equation is not known. This term is also the reason atmosphere and other fluids are chaotic in nature and small errors in $\mathbf{v}$ grow quickly because they multiply in this term. If the equation is linearized, $\nabla(\rho\mathbf{v}^{2})=0$, analytical solutions can be found. For example, Rossby, Kelvin, Poincare waves are all analytical solutions for a certain reduced set of linearized momentum or vorticity equations. It is important to identify that we need to have the non-linear advection term if we hope to produce accurate forecasts. Thus we solve the equations numerically.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;How to solve these PDEs? Processors are not capable of doing derivatives - they know how to &lt;em&gt;add&lt;/em&gt; and &lt;em&gt;multiply&lt;/em&gt; numbers. All other operations are derived from these two. We need to somehow approximate partial derivatives using basic arithmetic operations. The domain of interest (say, the globe) is discretized on a grid. Each grid cell will have a value for each of the state variables. For example, take the pressure gradient term in x-direction:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\nabla_{x}p = \dfrac{\partial p}{\partial x} \approx \dfrac{\Delta p}{\Delta x} = \dfrac{p_{i+1,j}-p_{i-1,j}}{2\Delta x_{i,j}}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $i,j$ are the grid indices in $x,y$. This example used &lt;a href=&quot;http://en.wikipedia.org/wiki/Finite_difference_method&quot;&gt;finite differences&lt;/a&gt;, centered in space. There are many other methods to discretize partial derivatives, and the ones that are in use in modern models are typically much more sophisticated than this example. If the grid spacing is not uniform, &lt;a href=&quot;http://en.wikipedia.org/wiki/Finite-volume_method&quot;&gt;finite volume methods&lt;/a&gt; must be used if the predicted quantitity is to be conserved. &lt;a href=&quot;http://en.wikipedia.org/wiki/Finite_element_method&quot;&gt;Finite element methods&lt;/a&gt; are more common for computational fluid dynamics problems defined on unstructured meshes in engineering, but can be used for atmosphere and ocean solvers as well. &lt;a href=&quot;http://en.wikipedia.org/wiki/Spectral_method&quot;&gt;Spectral methods&lt;/a&gt; are used in some global models like &lt;a href=&quot;http://en.wikipedia.org/wiki/Global_Forecast_System&quot;&gt;GFS&lt;/a&gt; and &lt;a href=&quot;http://en.wikipedia.org/wiki/Integrated_Forecast_System&quot;&gt;ECMWF&lt;/a&gt;. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Processes unresolved on the grid scale (term $\Phi$) are implemented in the form of parameterization schemes. Parameterized processes may include turbulence and boundary layer mixing, cumulus convection, cloud microphysics, radiation, soil physics, chemical composition etc. Parameterization schemes are still a hot research topic and they keep improving. There are many different schemes for all of the physical processes listed above. Some work better than the others in different meteorological scenarios.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Once all the terms in all the equations have been discretized on paper, the discrete equations are written in the form of a computer code. Most atmosphere, ocean circulation, and ocean wave models are written in Fortran. This is mostly for historical reasons - having long history, Fortran had the luxury of having very mature compilers and very optimized linear algebra libraries. Nowadays, with very efficient C, C++ and Fortran compilers available, it is more a matter of preference. However, Fortran code is still most prevalent in atmosphere and ocean modeling, even in recently started projects. Finally, an example code line for the above pressure gradient term would look like this:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;dpdx(i,j,k) = 0.5*(p(i+1,j,k)-p(i-1,j,k))/dx(i,j)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The whole code is compiled into machine language that is then loaded on the processor(s). The model program is typically not user friendly with a fancy graphical interface - it is most commonly run from dumb terminals on high-performance multiprocessor clusters. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Once started, the program discretely steps through time into the future. The calculated values for state variables at every grid point are stored in an output file, typically every hour (simulation time). The output files can then be read by visualization and graphics software to produce pretty images of model forecast. These are then used as guidance to forecasters to provide a meaningful and reasonable forecast.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2015-03-08T19:13:38.217" LastActivityDate="2015-03-08T19:13:38.217" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="667" PostTypeId="2" ParentId="665" CreationDate="2014-05-01T04:25:07.750" Score="7" Body="&lt;p&gt;Most earthquakes happen at the edges of the Earth's tectonic plates. Look at a better sample of earthquake epicenters collected using modern seismological techniques and compare to this &lt;a href=&quot;http://en.wikipedia.org/wiki/List_of_tectonic_plates&quot;&gt;List of tectonic plates&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earthquake epicenters are concentrated at the edges, and more sparse in plate interiors, but there are regions of high seismicity at high and low latitudes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you really want to know whether the concentration of earthquake epicenters is greater near the equator than near the poles, then you should try the following:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Divide the surface of the globe into &lt;strong&gt;~30 regions of equal area&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Make a table with a row for each region. Give the table two columns: the region's latitude (L), and the number of epicenters in the region (E).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) Compute the arithmetic average of E for all 30 regions, call this G. Take the square-root of G and call this D. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;4) Now look at your table.  How many regions have a concentration E&gt;5*G? How many of these are located at 'polar' latitudes and how many are located at 'equatorial' latitudes? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;5) If you find that 80% or more of the E&gt;5*G regions are in 'equatorial' regions, then that is probably evidence that significantly more earthquakes are measured in 'equatorial' regions. If you don't find this much, the effect is small.   &lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorUserId="178" LastEditDate="2014-05-01T17:07:51.320" LastActivityDate="2014-05-01T17:07:51.320" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="668" PostTypeId="1" AcceptedAnswerId="681" CreationDate="2014-05-01T05:36:30.927" Score="18" ViewCount="18206" Body="&lt;p&gt;Fundamentals of atmospheric modeling show that the height of the tropopause depends on the location, notably the latitude, and that the troposphere is roughly 8km higher at the equator than the poles depending on the time of year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First guess was that the temperature of the would impact its density (for example, here's the data for &lt;a href=&quot;https://www.wolframalpha.com/input/?i=air%20density%20at%20-50%C2%B0%20c&quot; rel=&quot;noreferrer&quot;&gt;-50°&lt;/a&gt; and &lt;a href=&quot;https://www.wolframalpha.com/input/?i=air%20density%20at%2050%C2%B0%20c&quot; rel=&quot;noreferrer&quot;&gt;50° c&lt;/a&gt;) - though this does not appear to show the cause of why is the troposphere 8km higher at the equator than the poles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Why is the troposphere 8km higher at the equator than the poles?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/XTu3M.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="284" LastEditDate="2014-05-01T11:30:26.437" LastActivityDate="2019-04-18T11:22:04.177" Title="Why is the troposphere 8km higher at the equator than the poles?" Tags="|troposphere|equator|poles|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="669" PostTypeId="1" AcceptedAnswerId="672" CreationDate="2014-05-01T08:08:52.513" Score="27" ViewCount="2333" Body="&lt;p&gt;Right, I saw a question about why the Earth spins counter clockwise, and it reminded me of something I would like to know the answer to. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I watched a episode of Futurama. In this episode the Earth stops spinning and they restart the Earth's spin, but going the other way (clockwise). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would the Earth function in the same way if this was possible to do? What effects could this have?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Note:&lt;/strong&gt; I'm not even 100% what way we are spinning - it depends how you look at it, right? &lt;/p&gt;&#xA;" OwnerUserId="347" LastEditorUserId="64" LastEditDate="2014-11-19T15:09:40.730" LastActivityDate="2014-11-19T15:09:40.730" Title="Would the Earth function the same spinning the other way?" Tags="|climate|planetary-science|hypothetical|earth-rotation|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="670" PostTypeId="1" CreationDate="2014-05-01T08:40:37.800" Score="11" ViewCount="6479" Body="&lt;p&gt;I found a rock in the Mojave desert and it resembles a tree branch including what appears to be wood grain. Is there some test or observation that can be done at home to conclusively answer my question? &lt;/p&gt;&#xA;" OwnerUserId="350" LastEditorUserId="20" LastEditDate="2014-05-27T02:28:59.247" LastActivityDate="2014-05-27T02:28:59.247" Title="How can I tell if a rock is really petrified wood?" Tags="|geology|fossils|paleobotany|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="671" PostTypeId="2" ParentId="608" CreationDate="2014-05-01T10:02:07.283" Score="10" Body="&lt;p&gt;As Peter Jansson pointed out, it adds up to 66.1 m of sea level rise. But what does that really mean for us? &lt;a href=&quot;http://flood.firetree.net/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's a nice interactive map tool&lt;/a&gt; where you can enter how much the sea level will rise and see what that does to our coast lines. So crank it up to 60m and look around.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously, The Netherlands will disappear almost entirely, as will most of Denmark and major parts of Germany. London will disappear. Most of the capitals in northern Europe will disappear under the sea. Scroll west to the US, and you can see that the entire eastern sea board will be flooded. Washington DC only just, but New York for the most part, and Boston entirely. On the west coast, San Francisco and Los Angeles will be a lot smaller, though parts of them are apparently high enough to survive. And before you think it's only the blue states that take a hit, take a look at Florida and Louisiana. The Mississipi south of Memphis becomes a massive sea inlet. Also, the most densely populated area of China gets flooded up to hundreds of km inland.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of the world's major population centers are at or near the coast, and almost all of them will be threatened by this level of sea rise.&lt;/p&gt;&#xA;" OwnerUserId="351" LastEditorUserId="351" LastEditDate="2019-05-09T11:43:48.343" LastActivityDate="2019-05-09T11:43:48.343" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="672" PostTypeId="2" ParentId="669" CreationDate="2014-05-01T10:26:55.063" Score="28" Body="&lt;p&gt;That would have many consequences. For example the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Coriolis_force&quot;&gt;Coriolis force&lt;/a&gt; would change the sign. Thus wind around pressure systems would switch the direction from north and south hemisphere, but also the &lt;a href=&quot;http://en.wikipedia.org/wiki/Ekman_spiral&quot;&gt;Ekman spiral&lt;/a&gt; in the ocean would be affected. Surface heating at sloped terrain will different, as the sun would rise in the West. This would change thermal induced circulations. And the conservation of angular momentum is important for the general circulation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would expect major impacts on the resulting climate, even in an equilibrium mode, which does not account for the acceleration to the oppose rotation velocity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During the time of stopped rotation additional circulation systems can be expected, which exchange energy between the day and the night side of the earth.&lt;/p&gt;&#xA;" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2014-10-06T17:21:28.570" LastActivityDate="2014-10-06T17:21:28.570" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="673" PostTypeId="2" ParentId="670" CreationDate="2014-05-01T10:55:36.363" Score="12" Body="&lt;p&gt;I don't think there is a really conclusive absolute test one can carry out without further preparations. In the case of a permineralised fossil, this would probably require thin sectioning and close examination to see if any cellular structure diagnostic of wood remains. Overall I'd think though that if it looks like wood and has been replaced by minerals, it probably is fossilised wood. However, you say  you found it in the desert, which perhaps could mean it is some kind of sub-fossil or mummified wood.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first thing to do would be the standard mineralogy tests to attempt to find out which mineral(s) replaced the wood.&lt;/p&gt;&#xA;" OwnerUserId="140" LastActivityDate="2014-05-01T10:55:36.363" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="674" PostTypeId="1" CreationDate="2014-05-01T11:26:46.490" Score="9" ViewCount="97" Body="&lt;p&gt;What properties does volcanic ash have that make it a hazard to aircraft jet engines which are not posed by other sources of atmospheric dust, such as Saharan dust? Is it merely a question of atmospheric concentration or relative height?&lt;/p&gt;&#xA;" OwnerUserId="140" LastActivityDate="2014-05-01T11:59:40.627" Title="Why does volcanic dust pose such a hazard to air travel?" Tags="|volcanic-hazard|atmospheric-dust|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="675" PostTypeId="2" ParentId="674" CreationDate="2014-05-01T11:59:40.627" Score="9" Body="&lt;p&gt;Particle size is the key issue. Saharan loess (wind-blown dust) &lt;em&gt;must&lt;/em&gt; have a small enough particle size that it can be lofted by ordinary wind speeds: typically, it is in the 20-50&amp;mu;m size range.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Particle sizes lofted into the upper atmosphere during explosive volcanic eruptions can be much higher: &quot;The explosive ash was bimodal in size distribution with peaks at about 25- and 200-&amp;mu;m diameter... For the&#xA;typical ash, diameter peaked at approximately 500&amp;mu;m&quot; (&lt;a href=&quot;http://www.pnas.org/content/108/18/7307.short&quot;&gt;Gislason &lt;em&gt;et al.&lt;/em&gt;, 2011&lt;/a&gt;), though this effect only has particular significance in close proximity to the vent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The risk to aircraft is explained:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Fears about danger to aircraft arose from an incident when a British Airways 747 flew through an ash cloud during the 1982 eruption of Mount Galunggung in Indonesia. The pilot reported sparks from the windows and wings as ash sandblasted all surfaces and all four jet engines failed when melted ash coated their interior.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(There's an absolutely classic paper on this, and a lot of the literature is well worth a read for the sheer understated &quot;well, yep, that was a problem.&quot;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact the ash lofted across Europe following the Eyjafjallaj&amp;ouml;kull eruption was mostly below 63&amp;mu;m in diameter, since that's what can persist without rapidly sedimenting out, but the explosive nature of the initial eruption meant that &quot;... even the nanoparticles are far from round. Their sharpness makes them particularly abrasive.&quot; In contrast, loess has been extensively weathered. The authors add: &quot;The very sharp, hard particles put aircraft at risk from abrasion on windows and body and from melting in jet engines.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For more details on volcanic ash and turbine engines, see &lt;a href=&quot;http://books.google.co.uk/books?hl=en&amp;amp;lr=&amp;amp;id=pKY_VLqMTgsC&amp;amp;oi=fnd&amp;amp;pg=PA107&amp;amp;dq=british+airways+flight+indonesia+volcanic+ash&amp;amp;ots=NcdgKDJ8CP&amp;amp;sig=vnDusHqPOqmwdxoT1n32uyV0nNQ#v=onepage&amp;amp;q=british%20airways%20flight%20indonesia%20volcanic%20ash&amp;amp;f=false&quot;&gt;Gunn &amp;amp; Wade&lt;/a&gt; and, for that matter &lt;a href=&quot;http://books.google.co.uk/books?hl=en&amp;amp;lr=&amp;amp;id=pKY_VLqMTgsC&amp;amp;oi=fnd&amp;amp;pg=PA87&amp;amp;dq=campbell+1991+aviation+volcano&amp;amp;ots=NcdgKDK5yI&amp;amp;sig=8g5igAjSeoTRitoNgYuvu_me-Mc#v=onepage&amp;amp;q=campbell%201991%20aviation%20volcano&amp;amp;f=false&quot;&gt;the rest of the volume&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-05-01T11:59:40.627" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="676" PostTypeId="1" AcceptedAnswerId="734" CreationDate="2014-05-01T12:43:44.123" Score="20" ViewCount="1614" Body="&lt;p&gt;There's been &lt;a href=&quot;http://www.dailymail.co.uk/news/article-1366603/Earthquake-map-America-make-think-again.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;news&lt;/a&gt; (some &lt;a href=&quot;http://guardianlv.com/2014/01/worst-earthquake-horror-happened-in-new-madrid-fault/&quot; rel=&quot;nofollow noreferrer&quot;&gt;recently&lt;/a&gt;) about the New Madrid fault and &lt;a href=&quot;http://www.thenation.com/blog/178449/whats-causing-huge-spike-earthquakes-oklahoma&quot; rel=&quot;nofollow noreferrer&quot;&gt;other active intra-plate faults&lt;/a&gt;.  For those living in the midwest of the United States, it's been a bit of a shock to learn they have to worry about earthquakes as well as &lt;a href=&quot;https://earthscience.stackexchange.com/q/573/330&quot;&gt;tornadoes&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Inter-plate faults, such as the San Andreas fault, get a lot of attention.  Plate friction from movement makes sense.  But, what is the current theory on these intra-plate fault zones?&lt;/p&gt;&#xA;" OwnerUserId="330" LastEditorDisplayName="user12525" LastEditDate="2019-04-22T13:57:38.213" LastActivityDate="2019-04-22T13:57:38.213" Title="What causes intra-plate faults, such as the New Madrid fault?" Tags="|geology|geophysics|plate-tectonics|structural-geology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="677" PostTypeId="2" ParentId="292" CreationDate="2014-05-01T13:06:56.110" Score="4" Body="&lt;p&gt;The intraplate compression responsible for this uplift has had a couple of explanations over the years; historically, it's been ascribed to Alpine collision, i.e. the collision of the Alpine orogen with the Europe. However &lt;a href=&quot;http://geology.gsapubs.org/content/36/11/839.short&quot; rel=&quot;nofollow&quot;&gt;Kley &amp;amp; Voight (2008)&lt;/a&gt; reviewed evidence and concluded it was the effect of Africa-Iberia-Europe convergence:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... the onset of intraplate contraction coincides with an important change in relative motion between the European and African plates. At ca. 90 Ma, Africa's SSE-directed sinistral transform motion relative to Europe changed to NE-directed convergence. This agrees well with the timing and kinematics of intraplate thrusting in central Europe. Structures of similar age and kinematics occurring in southern France, Spain, and North Africa suggest that the Late Cretaceous pulse of contraction was caused by pinching west-central Europe's thin lithosphere between Baltica and Africa. Only since the onset of N-directed thrusting in the Alps in Paleocene or Eocene time are the kinematics of the Alps and their European foreland compatible, indicating that mechanical coupling between Africa-Europe and the Adria microplate had been achieved. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-05-01T13:06:56.110" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="678" PostTypeId="1" AcceptedAnswerId="680" CreationDate="2014-04-01T21:26:38.800" Score="15" ViewCount="556" Body="&lt;p&gt;I understand why there is a daily inequality for high tides. What I do not understand is why the low tides are not equal. The data all seems to be somewhere along the lines of&lt;img src=&quot;https://i.stack.imgur.com/yHFOp.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;br&gt; but the theory seems to point to&lt;img src=&quot;https://i.stack.imgur.com/h67TQ.png&quot; alt=&quot;enter image description here&quot;&gt;&#xA;&lt;br&gt;That is, a greater daily inequality for high tide and none for low tide. I know that there are things to consider besides the moons influence, but the data pretty clearly rises above the noise in its consistency.&lt;br&gt;&lt;br&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="stellatedHexahedron" LastEditorUserId="129" LastEditDate="2014-05-01T15:39:29.890" LastActivityDate="2014-05-01T15:39:29.890" Title="Why is there a daily inequality for low tides?" Tags="|oceanography|tides|moon|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="679" PostTypeId="2" ParentId="678" CreationDate="2014-04-02T11:58:05.107" Score="3" Body="&lt;p&gt;You need to be careful about which port or beach you take the data from. It is not the same to measure tides on the eastern side of a gulf than on the western side, due to Moon's motion, and also it is not the same to take data at the far end of a gulf than on its mouth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think this last thing is what happens to your data.&lt;/p&gt;&#xA;" OwnerDisplayName="Envite" LastActivityDate="2014-04-02T11:58:05.107" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="680" PostTypeId="2" ParentId="678" CreationDate="2014-04-02T11:58:51.883" Score="11" Body="&lt;p&gt;The water for high tides needs to come from somewhere; the mean sea level should stay approximately constant, as long as wind is neglected. That way tides are a kind of oscillations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the first of the two diagrams a low low tide is followed by a high high tide, and a high low tide is followed by a low high tide. That way the mean sea level, averaged over one low tide - high tide period remains constant:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Evqxq.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the second diagram you need to average over two low tide - high tide periods to get a constant mean:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/1smrg.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first diagram can be explained by the superposition of semi-diurnal tides, while&#xA;the second diagram needs an additional diurnal constituent. Depending on the amplitude and phase shift of the diurnal constituent relative to the semi-diurnal constituent we can get different resulting oscillations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Tide&quot; rel=&quot;noreferrer&quot;&gt;More about tides and their constituents&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="Gerald" LastActivityDate="2014-04-02T13:40:07.873" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="681" PostTypeId="2" ParentId="668" CreationDate="2014-05-01T13:49:09.800" Score="7" Body="&lt;p&gt;To start with a definition, the tropopause is the boundary between troposphere and stratosphere; within the troposphere temperature decreases with increase in altitude (the temperature profile is dominated by radiative heat from the Earth's surface), whereas in the stratosphere temperature increases with altitude (the temperature profile is dominated by solar radiation).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Increases in troposphere temperature are associated with increase in tropopause height. Factors in play include the amount of water vapour being evaporated from equatorial seas; &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/JD090iD03p05629/full&quot;&gt;interannual variations in tropopause height can result from both local and large-scale driving forces&lt;/a&gt;. The tropopause responds to the average temperature of the entire underlying layer: this is higher at the equator and lower at the poles.&lt;/p&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-05-01T13:49:09.800" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="682" PostTypeId="2" ParentId="669" CreationDate="2014-05-01T14:14:22.037" Score="23" Body="&lt;p&gt;Depending on the assumptions you make, the Moon would suddenly have a retrograde orbit. If the moon had a retrograde orbit, it would have tremendous consequences. Retrograde orbits tend to become less distant over time, meaning the moon would either be much closer to the Earth with huge tidal effects or come more close in the future. At some point, the Moon would or would have passed the Earth's &lt;a href=&quot;http://en.wikipedia.org/wiki/Roche_limit&quot;&gt;Roche limit&lt;/a&gt;, break up, and create a temporary ring system which would shower the Earth with impacts.&lt;/p&gt;&#xA;" OwnerUserId="354" LastEditorUserId="354" LastEditDate="2014-05-04T10:55:52.020" LastActivityDate="2014-05-04T10:55:52.020" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="683" PostTypeId="1" AcceptedAnswerId="685" CreationDate="2014-05-01T14:48:11.460" Score="12" ViewCount="20836" Body="&lt;p&gt;Is Mount Everest becoming taller or shorter every year? By how much?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like an explanation in terms of tectonic plate movement if possible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/3q0LJ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&#xA;Source: IamKatieHoffman.com&lt;/p&gt;&#xA;" OwnerUserId="132" LastEditorDisplayName="user20559" LastEditDate="2021-05-17T20:41:23.127" LastActivityDate="2021-05-17T20:41:23.127" Title="Is Mount Everest currently becoming taller or shorter every year?" Tags="|geology|geophysics|plate-tectonics|mountains|isostasy|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="684" PostTypeId="1" CreationDate="2014-05-01T15:05:32.397" Score="11" ViewCount="5155" Body="&lt;p&gt;The answers to &lt;a href=&quot;https://earthscience.stackexchange.com/q/608/357&quot;&gt;this question&lt;/a&gt; say that the sea level will rise 66m if all the polar ice, etc, melts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How long will this take?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Transporting incredible amounts of heat energy to the poles and injecting it into the ice, a good insulator, so that it melts must be very, very slow. The Netherlands, London, and all the rest will be long gone for other reasons, I imagine, long before it could be completed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am looking for an order of magnitude minimum under which it is provably impossible for the ice to all melt any faster.  Wild and crazy assumptions are welcome, so long as they err on the side of making the ice melt faster than it would in reality - that way the estimate will always be a minimum.&lt;/p&gt;&#xA;" OwnerUserId="357" LastEditorUserId="11908" LastEditDate="2019-03-13T05:15:23.287" LastActivityDate="2019-03-13T05:15:23.287" Title="How long to melt all the polar ice?" Tags="|climate-change|sea-level|glaciology|ice-sheets|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="685" PostTypeId="2" ParentId="683" CreationDate="2014-05-01T16:02:01.887" Score="17" Body="&lt;p&gt;&lt;a href=&quot;http://www.nationalgeographic.com/features/99/everest/roof_content.html&quot;&gt;According to one survey&lt;/a&gt; using GPS mounted on a plateau below the summit, Mount Everest is increasing its height approximately 4mm each year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for plate techtonics, &lt;a href=&quot;http://www.thetech.org/exhibits/online/everest/about/platetectonics.htm&quot;&gt;this site&lt;/a&gt; describes it pretty simply:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Much like a car crashing head-on with a truck, crumpling occurred when the two continents met and the result was the creation of the Himalayan Mountains. Although the northward drift of India slowed dramatically with initial collision, the two continents have continued to converge as India slides under Asia.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="330" LastEditorUserId="330" LastEditDate="2014-05-01T16:07:58.540" LastActivityDate="2014-05-01T16:07:58.540" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="687" PostTypeId="2" ParentId="684" CreationDate="2014-05-01T17:44:56.460" Score="-6" Body="&lt;p&gt;We need some numbers.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;How much ice is there?  Let's look at the Antartic ice sheet, which will be the last to go, no matter what happens.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Antarctica contains  26.5 million cubic km of ice ( &lt;a href=&quot;http://en.wikipedia.org/wiki/Antarctic_ice_sheet&quot; rel=&quot;nofollow noreferrer&quot;&gt;reference&lt;/a&gt; )&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1cc = 1g&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1 km3 = 10 ** 15 cc&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So: $2 \times 10 ^{19}\,\mathrm{kg}$ )&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;How much heat energy is needed to melt a unit of ice?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$333\, \mathrm{kJ/kg}$. (&lt;a href=&quot;http://www.ask.com/question/how-many-joules-of-heat-are-required-to-melt-40-kg-of-ice-at-0-degress-c&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.ask.com/question/how-many-joules-of-heat-are-required-to-melt-40-kg-of-ice-at-0-degress-c&lt;/a&gt; )&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So we need $6 \times 10^{24}\,\mathrm{J}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I reckon that this is the amount of energy striking the entire Earth from the sun every two minutes.  However, getting this energy from the top of the atmosphere into the ice sheet will take a little longer.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;How good an insulator is ice?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$2\,\mathrm{W/mK}$ (&lt;a href=&quot;http://en.wikipedia.org/wiki/List_of_thermal_conductivities&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://en.wikipedia.org/wiki/List_of_thermal_conductivities&lt;/a&gt;)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Antarctic ice is about $2\,\mathrm{km}$ thick. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/6Ennh.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's replace this with a $1\,\mathrm{km}$ blanket of ice equivalent insulator.  In this case, if the mean air temperature ( currently -57C ) rises to $10\,^{\circ}\mathrm{C}$, then energy arrives at the bottom of the blanket ( where I assume the temperature has risen to 0 celsius and the pressure has fallen to 1 atmosphere ) at the rate of ... $0.02\,\mathrm{W/m^2}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Antarctica is  $14 \times 10 ^{6} \,\mathrm{km}^2$ so we are able to deliver energy at $3\times 10 ^7\,\mathrm{W}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\frac{6 \times 10 ^ {24}}{3 \times 10 ^ 7} = 2 \times 10^{17}\,\mathrm{s} \approx 7 \times 10^{9} \mathrm{years}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think we can all relax!&lt;/p&gt;&#xA;" OwnerUserId="357" LastEditorUserId="357" LastEditDate="2014-05-01T18:51:02.847" LastActivityDate="2014-05-01T18:51:02.847" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="688" PostTypeId="2" ParentId="684" CreationDate="2014-05-01T18:28:29.100" Score="10" Body="&lt;p&gt;Don't rest so easy, ravenspoint.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Laurentide ice sheet at its maximum extent was larger than the Antarctic ice sheet is now. The bulk of that ice sheet melted in two pulses of 2000 years each, separated by the ~1000 year long Younger Dryas. During the first pulse, the Laurentide lost 5400 km&lt;sup&gt;3&lt;/sup&gt; of ice pear year. During the second pulse, it lost ice at an even faster clip, 5600 km&lt;sup&gt;3&lt;/sup&gt; of ice pear year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://academic.macewan.ca/furzem/files/2011/10/Dyke-2004.pdf&quot;&gt;Dyke, A. S. (2004), &quot;An outline of North American Deglaciation with emphasis on central and northern Canada&quot; in &lt;em&gt;Quaternary Glaciations- Extent and Chronology, Part II&lt;/em&gt;, p. 373-424, J. Ehlers and P. L. Gibbard, eds, Elsevier.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You want a SWAG, so I'll use 5000 km&lt;sup&gt;3&lt;/sup&gt; per year. That's just 5000 years for the Antarctic ice sheets to melt. The Laurentide ice sheet was able to melt quickly because a good chunk of it was outside of the polar circle. That's not the case for the Antarctic ice sheet, so this 5000 years most likely is an overly aggressive estimate.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2014-05-01T19:02:59.463" LastActivityDate="2014-05-01T19:02:59.463" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="689" PostTypeId="1" AcceptedAnswerId="2809" CreationDate="2014-05-01T18:38:51.213" Score="11" ViewCount="1617" Body="&lt;p&gt;Blueschist has a mineral assemblage such that it must have formed at high pressures and low temperatures. It must therefore form in subducting slabs (and I believe this correlates with the locations in which it's found). However, that leaves the issue of how to &lt;em&gt;get&lt;/em&gt; it to the surface rapidly enough that it doesn't heat up sufficient to reequilibrate and lose the characteristic mineral assemblage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the currently favoured explanations/processes for such rapid exhumation from depth?&lt;/p&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-11-17T12:22:49.030" Title="Exhumation of blueschist" Tags="|subduction|metamorphism|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="690" PostTypeId="2" ParentId="684" CreationDate="2014-05-01T18:43:32.910" Score="16" Body="&lt;p&gt;The question is requesting an answer that has no practical application. So rather than improving on some hypothetical calculation, I will describe the problem and hopefully make the difficulty providing a real answer to a time frame clear.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First: &quot;polar ice&quot; Antarctica is located in a polar position and consists of a multi-km thick ice sheet. The Arctic is covered by sea ice except for smaller glaciers and Greenland, which is not located in a polar position equal to Antarctica. One has to remember that Antarctica is circulation-wise isolated from the rest of the planet by circumpolar circulation, both in th esea and atmosphere, a situation not met in the Arctic. Hence the term polar ice is very fuzzy and should be avoided. It is better to speak about the objects directly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second: an ice sheet such as Greenland and Antarctica is not a stagnant sheet of ice, it has its own dynamics and which can change over time depending on forcing and change in forcing.. Greenland is largely land based but with outlet glaciers that terminate in the sea. Although mass loss through these have seen an increase in loss, much of the Greenland mass gain and loss is through surface mass balance (snow accumulation minus ablation, melt). Antarctica is a different beast since East Antarctica is largely land based while West Antarctica is to a large extent sitting on ground below (in places several km) below sea level. Te latter situation is more unstable since the ice could disintegrate by calving (loss through ice berg formation), a process which is potentially much quicker than surface melt (of which there is currently very little in Antarctica). So one part of Antarctica is much more unstable than the other. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, several other processes are at play. Ocean currents are sen to produce massive amounts of submarine melt on both Greenland outlet glaciers as well as on the sea-terminating edges of Antarctica. In places, circulation models estimate up to equal loses by calving an submarine melt. This occurs at the same time as there is hardly any surface melt to speak of. So calculating mass loss by surface melt is clearly a lost cause when calving and submarine melt dominate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, in this still simplified picture, the dynamic response of the ice sheets to changes in forcing is not well understood. This means we do not know &lt;em&gt;how&lt;/em&gt; unstable East Antarctica really is. That Antarctica will totally disappear seems very unlikely any time soon and time frames of 10^3-10^4 years is a minimum. Greenland, not being a polar ice sheet is more sensitive in that as it loses mass it is also on average lower in altitude, experiencing more melt. There appears to be a point of no return for Greenland, under which elevation the ice sheet would not be able to recuperate unless the climate cooled significantly. Again the time to melt off the ice is long.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;despite the seemingly slow increase in sea level, much infra structure  in the coastal environments is threatened by only dm to m changes in ea level so the 66.1 m quoted from IPCC is not something that will happen in a life time but that does not mean the rates are not already problematic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a PS, I will add some relevant references once I am back home in case someone misses them at the moment.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="81" LastEditDate="2014-05-01T19:29:29.723" LastActivityDate="2014-05-01T19:29:29.723" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="691" PostTypeId="1" AcceptedAnswerId="799" CreationDate="2014-05-01T18:46:20.050" Score="10" ViewCount="3162" Body="&lt;p&gt;Chert and flint are commonly found in chalky deposits (and have obvious importance in human history as tools). What are the processes of diagenesis of these silica-rich nodules in otherwise silica-poor horizons?&lt;/p&gt;&#xA;" OwnerUserId="105" LastEditorUserId="94" LastEditDate="2014-05-06T10:44:54.900" LastActivityDate="2014-05-06T10:44:54.900" Title="Formation of flint &amp; chert in limestones/chalk" Tags="|diagenesis|sedimentology|carbonate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="692" PostTypeId="2" ParentId="627" CreationDate="2014-05-01T19:02:24.223" Score="3" Body="&lt;p&gt;Here's a list of AGU (American Geophysical Union) sections. Each section is composed of committees with specialized sub-disciplines. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Atmospheric and Space Electricity, Near Surface Geophysics,&#xA;  Atmospheric sciences, Nonlinear Geophysics, Biogeosciences, Ocean&#xA;  Sciences, Cryospheric Sciences, Paleoceanography and Paleoclimatology,&#xA;  Earth and Planetary Surface Processes, Planetary science, Earth and&#xA;  Space Science Informatics, Seismology, Geodesy, Societal Impacts and&#xA;  Policy Sciences, Geomagnetism and Paleomagnetism, Space Physics and&#xA;  Aeronomy, Global Environmental Change, Studies of the Earth's Deep&#xA;  Interior, Hydrology, Tectonophysics, Mineral and Rock Physics,&#xA;  Volcanology, Geochemistry, Petrology, Natural Hazards &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Reference: &lt;a href=&quot;http://sites.agu.org/leadership/sections-focus-groups/&quot; rel=&quot;nofollow&quot;&gt;AGU Sections/Focus Groups&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Is there anything that doesn't fit within one of these top-level categories?&lt;/p&gt;&#xA;" OwnerUserId="152" LastEditorUserId="284" LastEditDate="2014-05-01T19:52:46.557" LastActivityDate="2014-05-01T19:52:46.557" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="693" PostTypeId="2" ParentId="324" CreationDate="2014-05-01T19:48:48.180" Score="2" Body="&lt;p&gt;Double terminated crystals normally form in free floating pockets of liquid that slowly evaporated, leaving perfectly formed crystals with terminations on both sides.&#xA;Unlike usual quartz formations which grow in igneous rock, double terminated crystals are more than likely found in sedimentary rock laid down by subterranean marine deposits a long time ago. Occasionally, rare clusters of double terminated crystals form – very unique!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://c1.staticflickr.com/1/29/53123748_ca9d1547f6_z.jpg&quot; alt=&quot;double-terminated-crystal&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="181" LastEditorUserId="115" LastEditDate="2014-12-07T15:13:31.537" LastActivityDate="2014-12-07T15:13:31.537" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="694" PostTypeId="1" CreationDate="2014-05-01T20:06:58.940" Score="21" ViewCount="2124" Body="&lt;p&gt;I have been having a miserable time this week reading &lt;a href=&quot;http://www.seg.org/documents/10161/77915/seg_y_rev1.pdf&quot;&gt;SEGY&lt;/a&gt; files. This is data from the largest seismic acquisition company in the world whose client is the 7th largest oil company in the world. So if anyone could get it right you would think it would be these two. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The SEGY standard for storing seismic data is used throughout the oil industry but is showing it's age quite badly. Problems include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;non standard header information&lt;/li&gt;&#xA;&lt;li&gt;the textual header can be in ASCII or EBCDIC&lt;/li&gt;&#xA;&lt;li&gt;crazy machinations to save a few bytes&lt;/li&gt;&#xA;&lt;li&gt;binary data stored in IEEE or IBM floating point&lt;/li&gt;&#xA;&lt;li&gt;etc. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Some of the most glaring deficiencies are being patched up with a v2 release in the works. Details are here: &lt;a href=&quot;http://www.seg.org/documents/51956/6062543/SEGY+2.0+draft+February+2014&quot;&gt;http://www.seg.org/documents/51956/6062543/SEGY+2.0+draft+February+2014&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is not a standard you can implement just by reading the spec and this new version won't help fix that. The continual abuse of the standard means that it takes calendar years to 'debug into existence' a library that can withstand real world data files. This is hugely frustrating for both the software developers and the geoscientists who have to work with it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There was a discussion on &lt;a href=&quot;http://www.agilegeoscience.com/&quot;&gt;this excellent blog&lt;/a&gt; recently where HDF5 was mentioned &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.agilegeoscience.com/journal/2014/3/27/how-to-load-seg-y-data.html&quot;&gt;http://www.agilegeoscience.com/journal/2014/3/27/how-to-load-seg-y-data.html&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.agilegeoscience.com/journal/2014/3/26/what-is-seg-y.html&quot;&gt;http://www.agilegeoscience.com/journal/2014/3/26/what-is-seg-y.html&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I would prefer to see a new standard that is less complicated than SEGY and with no dependencies on third party libraries. So while I think technologies like &lt;a href=&quot;http://www.hdfgroup.org/HDF5/&quot;&gt;HDF5&lt;/a&gt; (and &lt;a href=&quot;http://sourceforge.net/apps/mediawiki/javaseis/index.php?title=Main_Page&quot;&gt;JavaSeis&lt;/a&gt; etc.) may have a role within a company they are not a replacement for SEGY. Even a technology like XML is going to be outlived by the data files we will have to read in the future. So I think the format will need to be extremely simple and conservative. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some features of a format that could replace SEGY might include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;one character encoding (ASCII or UTF-8)&lt;/li&gt;&#xA;&lt;li&gt;all headers in human readable form – key-value pairs?&lt;/li&gt;&#xA;&lt;li&gt;mandatory header information, e.g. shotpoints, x/y locations etc. &lt;/li&gt;&#xA;&lt;li&gt;standard unit definitions, map projections etc. &lt;/li&gt;&#xA;&lt;li&gt;traces may be binary but only IEEE&lt;/li&gt;&#xA;&lt;li&gt;data should be in one file (SEGY got this right)&lt;/li&gt;&#xA;&lt;li&gt;no data compression&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So now for the question – what do we have to do to move beyond the extremely frustrating SEGY standard? Is there anything out there already we should just start evangelizing? If not, what do you think a replacement format needs to look like? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for reading. I feel much better after this rant and will get back to debugging why byte number 3603 is wrong. &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;EDIT: After chilling out over the weekend here are some more thoughts. SEGY is complicated for a number of reasons:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;inherent complexity&lt;/li&gt;&#xA;&lt;li&gt;accidental complexity&lt;/li&gt;&#xA;&lt;li&gt;different expectations for the format from users&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So SEGY is hard to use because the seismic problem domain is an inherently difficult one to model. We are lucky to have the benefit of the wisdom of those who came up with the format. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even so, a lot of cruft has accumulated in the format over the years. This creates a non-trivial cognitive burden that I could do without but will realistically just have to deal with. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The last point though is interesting. We already have SEGD for storing the raw field data. This format is a lot more challenging than SEGY but is also a good place to bury a lot of the inherent complexity of real world seismic data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When people suggest HDF as a replacement I guess that (maybe) they are viewing SEGY as a 'processing' format? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Last week I was thinking of SEGY as a vehicle for sharing final seismic volumes with interpreters. I read at the weekend that 80% of SEGY headers are not populated in real world data. So, this is speculation on my part, but perhaps what we need is&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;SEGD for raw field data&lt;/li&gt;&#xA;&lt;li&gt;something else for actually processing &lt;/li&gt;&#xA;&lt;li&gt;and something else again for sharing data between processors and interpreters&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;To accurately, and reproducibly, load seismic data into interpretation systems we don't need much meta-data but it absolutely does need to be present. The hand-off from processors to interpreters via SEGY is where I think we could use a new approach. &lt;/p&gt;&#xA;" OwnerUserId="8" LastEditorUserId="20" LastEditDate="2014-05-18T16:06:10.593" LastActivityDate="2015-12-11T06:26:21.560" Title="What would a replacement for SEGY look like?" Tags="|geophysics|seismology|informatics|data-formats|" AnswerCount="4" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="695" PostTypeId="2" ParentId="683" CreationDate="2014-05-01T20:58:34.067" Score="7" Body="&lt;p&gt;To put it very short and sweet, yes, it is getting taller.&#xA;&lt;p&gt;&#xA;It is getting taller because the Indian-Australian and the Eurasian plates are continuing to collide. Also, from what I have read, the amount by which its height increases every year is apparently somewhat undecided as some sources say it is growing by as much as 30&quot; per year, while others say just 4 mm per year. Here are two links that I think are fairly informational, and where I obtained most of my information. P.S. Lovely photo:)&#xA;&lt;a href=&quot;http://www.extremescience.com/everest.htm&quot;&gt;http://www.extremescience.com/everest.htm&lt;/a&gt;&#xA;&lt;p&gt;&#xA;&lt;a href=&quot;http://www.nationalgeographic.com/features/99/everest/roof_start.html&quot;&gt;http://www.nationalgeographic.com/features/99/everest/roof_start.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="342" LastActivityDate="2014-05-01T20:58:34.067" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="696" PostTypeId="5" CreationDate="2014-05-01T21:55:51.247" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-05-01T21:55:51.247" LastActivityDate="2014-05-01T21:55:51.247" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="697" PostTypeId="4" CreationDate="2014-05-01T21:55:51.247" Score="0" Body="Questions regarding large bodies of salt water known as oceans. These bodies comprise about 70% of the Earth's surface." OwnerDisplayName="user13" LastEditorUserId="111" LastEditDate="2014-08-15T20:22:36.330" LastActivityDate="2014-08-15T20:22:36.330" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="698" PostTypeId="2" ParentId="694" CreationDate="2014-05-01T22:00:59.883" Score="11" Body="&lt;p&gt;I've done work with SEGY files, and the fixed length headers with ignored fields were an issue. Also, endian issues. &#xA;You have to remember SEGY is the present exchange and archiving standard. That's a good thing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The issue is that SEGY was designed for tape, so it's a single file.&#xA;In this day and age, that may not be a good thing. It might be better to allow for extended 'metadata' to be housed as a separate file. Basically, the catalog record that you could review before buying the data. And you should be able to add this metadata back into the file.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this was done as exchange profiles. Basically information groups rather than one large information block then a different format might get more buy in, and compliance over time. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for HDF, and other formats, it's about how the data structures are laid out. There can be some performance issues with how timeseries data access (~traces) is organized in NetCDF files.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some features of a format that could replace SEGY might include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;one character encoding (ASCII or UTF-8)&#xA;&lt;ul&gt;&#xA;&lt;li&gt;yes&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;all headers in human readable form - key value pairs?&#xA;&lt;ul&gt;&#xA;&lt;li&gt;yes&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;mandatory header information eg shotpoints, xy locations etc. &#xA;&lt;ul&gt;&#xA;&lt;li&gt;I would say yes, but I don't think that is going to happen.&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;standard unit definitions, map projections etc. &#xA;&lt;ul&gt;&#xA;&lt;li&gt;yes,&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;traces may be binary but only IEEE&lt;/li&gt;&#xA;&lt;li&gt;data should be in one file (SEGY got this right)&#xA;&lt;ul&gt;&#xA;&lt;li&gt;All data, yes. All information, no.&lt;/li&gt;&#xA;&lt;li&gt;single package like a tar file, yes&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;no data compression&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Bits are cheap. Include details of the used dictionary items in the file. In this day and age, we don't need to have a translation book external to the file. But we should use standard reference terms that are online as Linked Open Data.&lt;/p&gt;&#xA;" OwnerUserId="48" LastActivityDate="2014-05-01T22:00:59.883" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="699" PostTypeId="5" CreationDate="2014-05-01T22:05:07.953" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-05-01T22:05:07.953" LastActivityDate="2014-05-01T22:05:07.953" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="700" PostTypeId="4" CreationDate="2014-05-01T22:05:07.953" Score="0" Body="Questions regarding large land masses that reach high above the surrounding terrain, usually forming a peak." OwnerDisplayName="user13" LastEditorDisplayName="user13" LastEditDate="2014-05-02T18:28:46.030" LastActivityDate="2014-05-02T18:28:46.030" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="701" PostTypeId="5" CreationDate="2014-05-01T22:06:53.700" Score="0" Body="&lt;p&gt;An &lt;a href=&quot;https://en.wikipedia.org/wiki/Earthquake&quot; rel=&quot;nofollow noreferrer&quot;&gt;earthquake&lt;/a&gt; (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth, resulting from the sudden release of energy in the Earth's lithosphere that creates seismic waves.&lt;/p&gt;&#xA;" OwnerUserId="-1" LastEditorUserId="11908" LastEditDate="2019-02-03T19:38:28.987" LastActivityDate="2019-02-03T19:38:28.987" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="702" PostTypeId="4" CreationDate="2014-05-01T22:06:53.700" Score="0" Body="Questions regarding a sudden release of seismic waves into the Earth's crust. As well as the causes of earthquakes, their consequences and physics." OwnerDisplayName="user13" LastEditorUserId="11908" LastEditDate="2019-02-03T19:38:28.987" LastActivityDate="2019-02-03T19:38:28.987" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="703" PostTypeId="2" ParentId="562" CreationDate="2014-05-01T23:46:25.133" Score="13" Body="&lt;p&gt;Your guess A is correct. Iron, nickel, and other heavy metals like gold, are what makes up the core of the earth because they are the heaviest of the metals and so sank toward the center of the earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, since the earth is believed to have been made out of loose material (asteroids) out in space, it would make sense that it would be made out of much of the same materials as the asteroids themselves. Which, I guess, would make C partially correct also.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;B is not correct because, (as pointed out in Spießbürger's answer):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The magnetic field needs a liquid iron core to work and therefore only&#xA;  came into existence after the iron migrated to the core.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="115" LastEditorUserId="181" LastEditDate="2014-05-02T02:51:01.090" LastActivityDate="2014-05-02T02:51:01.090" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="704" PostTypeId="1" CreationDate="2014-05-01T23:49:41.853" Score="4" ViewCount="620" Body="&lt;p&gt;So moisture decreases the temperature lapse rate (relative to the dry adiabat). My question is this: does a cloud decrease the lapse rate at the same rate as 100% humidity would decrease it? Or would it depend on cloud type (e.g. stratus vs cumulus)?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="64" LastEditDate="2014-05-02T02:14:31.433" LastActivityDate="2014-05-02T22:33:38.567" Title="How does the lapse rate in clouds compare with the lapse rate of air?" Tags="|atmosphere|meteorology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="705" PostTypeId="1" CreationDate="2014-05-01T23:55:38.630" Score="6" ViewCount="1791" Body="&lt;p&gt;As quoted from the AR5 IPCC report (chapter 7) &lt;a href=&quot;http://www.ipcc.ch/report/ar5/wg1/&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Most high cloud (mainly cirrus and deep cumulus &#xA;  outflows) occurs near the equator and over tropical continents, but can &#xA;  also be seen in the mid-latitude storm track regions and over mid-lati-&#xA;  tude continents in summer (Figure 7.6a, e)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="10" LastEditorUserId="64" LastEditDate="2014-05-02T02:44:49.157" LastActivityDate="2014-05-02T04:21:58.760" Title="Why are most cirrus clouds present over the equator and over tropical continents?" Tags="|atmosphere|meteorology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="706" PostTypeId="1" AcceptedAnswerId="768" CreationDate="2014-05-02T00:05:08.870" Score="9" ViewCount="846" Body="&lt;p&gt;Absolute dating is the process of determining an approximate computed age of something like a fossil. How does that work?&lt;/p&gt;&#xA;" OwnerUserId="115" LastEditorUserId="87" LastEditDate="2014-05-05T13:14:42.803" LastActivityDate="2014-05-05T13:14:42.803" Title="How do scientists determine the absolute or 'chronometric' date of fossils?" Tags="|fossils|geochronology|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="707" PostTypeId="1" AcceptedAnswerId="714" CreationDate="2014-05-02T00:06:31.393" Score="13" ViewCount="212" Body="&lt;p&gt;Cloud forcing is still one of the major uncertainties of radiative forcing in climate modeling because there are so many uncertainties in it (and parametrizations). But also because the timescale of cloud development are much shorter than the timescale that climate models are run at.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I'm curious: are clouds much easier to simulate in the short timespans of weather models? Or are they still a beast to simulate in them?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="111" LastEditDate="2014-05-02T20:19:29.330" LastActivityDate="2014-05-03T09:36:21.027" Title="Are clouds significantly easier to simulate in weather models than climate models?" Tags="|atmosphere|meteorology|climate|nwp|climate-models|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="708" PostTypeId="1" CreationDate="2014-05-02T00:36:56.747" Score="10" ViewCount="298" Body="&lt;p&gt;As seen in the figure below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The larger the temperature difference between surface and cloud, the more positive the radiative forcing is from the cloud.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So as the cloud moves up, it supposedly should move into a colder altitude. But doesn't climate change also increase the temperatures at any given altitude too? If so, why does the cloud move up into a colder altitude due to climate change? (even after accounting for heating at the given altitude?)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/aXUzR.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="64" LastEditDate="2014-05-02T02:43:00.047" LastActivityDate="2016-06-29T15:44:20.563" Title="Why does the rising of high clouds due to climate change impart positive radiative feedback on radiative forcing?" Tags="|atmosphere|meteorology|climate|climate-change|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="709" PostTypeId="1" AcceptedAnswerId="715" CreationDate="2014-05-02T01:35:18.243" Score="18" ViewCount="18604" Body="&lt;p&gt;Mohs Hardness Scale is basically a measurement of the hardness of a material, or more specific, a rock or mineral. But I have never been able to figure out why some minerals are harder than others.&lt;/p&gt;&#xA;" OwnerUserId="115" LastEditorDisplayName="user12525" LastEditDate="2019-04-24T08:15:42.730" LastActivityDate="2022-12-19T12:06:40.177" Title="What determines a mineral's hardness?" Tags="|geology|mineralogy|minerals|crystals|crystallography|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="710" PostTypeId="2" ParentId="708" CreationDate="2014-05-02T01:51:30.853" Score="11" Body="&lt;p&gt;The primary mechanism at work here is the type of clouds that exist at different altitudes.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Low clouds of the cumulus or strato-cumulus variety are optically thick and reflective.  These types of clouds will scatter more light than they transmit or absorb, and the energy scattered upward and back into space will not contribute to warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;High clouds outside of convection tend to be cirrus clouds, which are icy and not optically thick.  These clouds let light pass through freely (you can see the sun through these clouds).  This lets solar energy through but they will absorb longwave (terrestrial) radiation, and this is what will contribute to warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is where a lot of the uncertainty in cloud feedbacks in a warming climate comes from.  If we get more clouds -- low, bright clouds, then this could contribute to cooling, wheras high, transparent (to shortwave) clouds would contribute to warming.  Again, it is not so much the high vs low that matters here, it is the properties of typical clouds at these heights.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-05-02T01:51:30.853" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="711" PostTypeId="2" ParentId="704" CreationDate="2014-05-02T02:42:03.833" Score="4" Body="&lt;p&gt;The lapse rate of temperature is ignorant of clouds, it only cares that either $e/e_s &amp;lt; 1$ (dry) or $e/e_s &amp;gt;= 1$ (moist), where $e$ is vapor pressure and $e_s$ is saturation vapor pressure.  A cloud is saturated (and in places supersaturated) and so the lapse rate will be the same as saturated air outside of a cloud.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The theoretical parcel at 100% humidity when subsequently lifted (in the presence of cloud condensation nuclei (CCN)) will itself experience nucleation and condensation and become a cloud.  In this respect there can be no difference between the saturated parcel outside of a cloud and a saturated parcel within a cloud, both will experience the same lapse rates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With that said, some types of clouds will cause a difference.  Consider a parcel at its level of free convection (LFC) within a deep convective cloud and a parcel far from the cloud, saturated in clear air at the same height.  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The parcel in clear air when lifted will cool at the moist lapse rate but entrain the surrounding dry air and the result will be less than moist adiabatic.  The entrainment will also limit the vertical extent of the parcels buoyancy.&lt;/li&gt;&#xA;&lt;li&gt;The parcel in the deep cloud will be saturated in a moist environment and will rise and cool at the moist adiabatic rate.  As it is inside the cloud, we'll say entrainment is not important.  This parcel will also rise high enough for ice processes to become important and will experience additional warming due to the enthalpies of sublimation and fusion (latent heat released from vapor-&gt;solid and liquid-&gt;solid transitions).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In this perspective, the parcel in the cloud to have a different temperature profile than the out of cloud parcel.  This isn't because of any difference in the moist lapse rate between the parcels or even how the thermodynamics work out, but rather because of the dynamic effect of entrainment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another factor to consider are the radiative properties of clouds vs clear air.  Clouds will absorb terrestrial longwave radiation and warm, and the water vapor in humid air will do the same thing.  Also on the periphery of the cloud where entertainment and evaporation is taking place, there will be some cooling from the phase change.  I don't have back of the envelope estimates for either of these effects, and I feel they are probably tangential to the question asked if we limit consideration of the cloud parcel to a parcel well inside of a deep cloud.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2014-05-02T22:33:38.567" LastActivityDate="2014-05-02T22:33:38.567" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="712" PostTypeId="2" ParentId="706" CreationDate="2014-05-02T03:31:22.477" Score="6" Body="&lt;p&gt;Typically this is accomplished through &lt;a href=&quot;http://en.wikipedia.org/wiki/Radiometric_dating&quot; rel=&quot;nofollow&quot;&gt;radiometric dating&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While this is a complex field and the article I've provided a link for explains it better than I could here, the short answer is that different elements' isotopes decay to at a known rate, and by measuring the quantities of the isotopes in question (which are chosen depending on the approximately estimated age of the sample), the age of the sample can be calculated.&lt;/p&gt;&#xA;" OwnerUserId="133" LastEditorUserId="133" LastEditDate="2014-05-04T22:25:10.813" LastActivityDate="2014-05-04T22:25:10.813" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="713" PostTypeId="2" ParentId="705" CreationDate="2014-05-02T04:21:58.760" Score="5" Body="&lt;p&gt;Clouds require moisture and therefore high clouds will exist in regions with upper-level moisture.  Synoptic scale ascent is on the order of cm/s and this is not an efficient way to bring moisture from the surface to the upper levels.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider this water vapor imagery:&lt;br&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/ibT5x.gif&quot; alt=&quot;Water vapor&quot;&gt; &#xA;&lt;sub&gt;Source: College of Dupage NEXLAB&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this image, the color represents the humidity of the mid and upper levels of the troposphere.  Brighter colors represent moisture at higher levels.  Darker colors represent moisture at mid levels.  Black represents dry mid and upper levels.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The brightest whites (highest level moisture) at this time are along the ITCZ and associated a mid-latitude cyclone in the northeastern US.  These are areas associated with convection, which unlike the synoptic scale flows is an efficient transport of moisture into the upper troposphere.  This convective outflow will first be associated with the &quot;anvil&quot; top of the thunderstorm, but as it is advected at the upper levels can manifest as cirrus clouds.  The ITCZ is driven by equatorial convergence and the upward branch of the Hadley cells.&#xA;Mid-latitude cyclones have a so-called &quot;wet conveyor belt&quot; that transports near-surface moisture into the mid and upper levels which can then manifest as upper level clouds (or lots of rain/snow). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer &quot;why are most cirrus clouds in the tropics?&quot; I would associate that with the large transport of water vapor into the upper levels by the persistent convection in the ITCZ. &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-05-02T04:21:58.760" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="714" PostTypeId="2" ParentId="707" CreationDate="2014-05-02T04:53:46.267" Score="6" Body="&lt;p&gt;The answer to this question depends on what process one is interested in simulating well. As you know, short/mid-range weather prediction models and climate models have very different applications and goals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because the short range weather prediction model is typically of much higher resolution than climate models (~1-10 km versus ~50-200 km), it is almost always more skilled at simulating clouds forming at a specific location and time. Cloud and rain prediction skill tends to be greater in synoptic scale fronts and near topographic features, and smaller for sporadic, small-scale, tropical thunderstorms. In very high-resolution NWP models (2-3 km or smaller), convection and clouds may be simulated reasonably well without using any cloud parameterization scheme. Nevertheless, clouds and rainfall are still hard to simulate or forecast very accurately.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, due to very low grid resolution, climate models can really aim only for correctly simulating the occurrence frequency and the amount of clouds and rain in a larger geographical region over a longer period of time. In climate, clouds play a significant role in radiative feedbacks. Climate models still rely on cloud parameterization schemes. &lt;/p&gt;&#xA;" OwnerUserId="192" LastActivityDate="2014-05-02T04:53:46.267" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="715" PostTypeId="2" ParentId="709" CreationDate="2014-05-02T06:15:04.353" Score="13" Body="&lt;p&gt;The hardness of minerals is diagnostic because the hardness is determined by the strength of bonds and the structure of the mineral lattice. Hardness is basically the stress required to create and grow extended lattice defects such as micro-fractures, stress twins, and dislocations.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Diamond, quartz, and framework silicates, such as feldspar, are hard because they have a three-dimensional lattice of covalently bonded atoms. Native metals are soft because they have close-packing lattices of metallic bonded atoms.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hardness is an intrinsic property of a mineral like density or refractive index.&lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorUserId="115" LastEditDate="2014-05-09T01:47:06.683" LastActivityDate="2014-05-09T01:47:06.683" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="716" PostTypeId="2" ParentId="238" CreationDate="2014-05-02T12:33:00.233" Score="-2" Body="&lt;p&gt;Cross tropopause transport seems to be the main driver : Take a look at &lt;a href=&quot;http://www.climatemonitor.it/wp-content/uploads/2014/04/Kuhl_Tropopause_Folding.ppt&quot; rel=&quot;nofollow&quot;&gt;this&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="313" LastActivityDate="2014-05-02T12:33:00.233" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="717" PostTypeId="5" CreationDate="2014-05-02T13:57:43.713" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-05-02T13:57:43.713" LastActivityDate="2014-05-02T13:57:43.713" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="718" PostTypeId="4" CreationDate="2014-05-02T13:57:43.713" Score="0" Body="Palaeobotany is the branch of paleobiology dealing with the recovery and identification of plant remains from geological contexts, and their use for the biological reconstruction of past environments (paleobiogeography), and both the evolutionary history of plants, with a bearing upon the evolution of life in general." OwnerUserId="140" LastEditorUserId="140" LastEditDate="2014-05-02T18:29:32.240" LastActivityDate="2014-05-02T18:29:32.240" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="719" PostTypeId="5" CreationDate="2014-05-02T14:03:55.697" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-05-02T14:03:55.697" LastActivityDate="2014-05-02T14:03:55.697" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="720" PostTypeId="4" CreationDate="2014-05-02T14:03:55.697" Score="0" Body="Taphonomy is the study of the post-death decay of organisms and the processes by which they may become preserved in the fossil record. The term taphonomy derives from the Greek taphos, τάφος meaning burial, and nomos, νόμος meaning law. " OwnerUserId="140" LastEditorUserId="140" LastEditDate="2014-05-02T18:28:51.807" LastActivityDate="2014-05-02T18:28:51.807" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="721" PostTypeId="5" CreationDate="2014-05-02T14:13:12.020" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-05-02T14:13:12.020" LastActivityDate="2014-05-02T14:13:12.020" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="722" PostTypeId="4" CreationDate="2014-05-02T14:13:12.020" Score="0" Body="Diagenesis describes the chemical, physical and biological processes by which sediments are formed into a sedimentary rock (a possible synonym is lithification). Diagenesis literally means &quot;two origins&quot;." OwnerUserId="140" LastEditorUserId="140" LastEditDate="2014-05-02T18:28:17.333" LastActivityDate="2014-05-02T18:28:17.333" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="723" PostTypeId="1" AcceptedAnswerId="777" CreationDate="2014-05-02T14:36:38.883" Score="15" ViewCount="306" Body="&lt;p&gt;Aquifers have a natural recharge rate.  However, some aquifers rely on &lt;a href=&quot;http://en.wikipedia.org/wiki/Fossil_water&quot;&gt;fossil water&lt;/a&gt; for their primary (or even sole) water supply.  When water in a well is pulled from these aquifers faster than they can replenish, the level drops and they eventually &quot;dry up&quot; (or the water table drops below the bottom of the well, at least).  In the case of aquifers with no recharge, such as fossil water, it seems that the water could literally be used up so that the aquifer becomes completely dry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For these fossil water aquifers, is there any known technique to recharge them?  Since they're labelled as a non-renewable resource, I presume the answer is &quot;no&quot;, but I'd like to get a better understanding of this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For aquifers with a low recharge rate and a severly dropped water table, is there any known way to increase their recharge rate?&lt;/p&gt;&#xA;" OwnerUserId="330" LastEditorUserId="79" LastEditDate="2014-05-05T14:38:03.047" LastActivityDate="2014-05-05T14:38:03.047" Title="Recharge a dry aquifer?" Tags="|hydrology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="724" PostTypeId="1" CreationDate="2014-05-02T16:12:17.330" Score="28" ViewCount="3253" Body="&lt;p&gt;El Niño is associated with the weakening of the ‘normal’ pressure/temperature gradients between the western and eastern Pacific Oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is this: why does it only exist in the Pacific Ocean?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could it be that the Atlantic is always in an ‘El Niño’ state too, given that the pressure/temperature gradients in the Atlantic aren't as steep as those of the Pacific to begin with?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="111" LastEditDate="2017-01-11T14:50:00.720" LastActivityDate="2017-05-18T18:56:37.517" Title="Why does El Niño only exist in the Pacific Ocean and not the Atlantic/Indian Oceans?" Tags="|atmosphere|ocean|enso|nao|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="725" PostTypeId="1" AcceptedAnswerId="731" CreationDate="2014-05-02T18:01:44.627" Score="20" ViewCount="47620" Body="&lt;p&gt;I know the focus of an earthquake is where the earthquake originated from, but what I could never figure out is, how to scientists find out where exactly the focus (and epicenter) are located?&lt;/p&gt;&#xA;" OwnerUserId="115" LastEditorUserId="115" LastEditDate="2014-05-02T18:10:17.970" LastActivityDate="2021-09-18T16:07:39.570" Title="How do seismologists locate the epicenter and focus of an earthquake?" Tags="|geophysics|geology|earthquakes|seismology|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="728" PostTypeId="2" ParentId="689" CreationDate="2014-05-02T19:17:23.633" Score="4" Body="&lt;p&gt;I don't know whether its currently the favoured explanation, but in California people made reference to something informally referred to as the &lt;a href=&quot;http://science.kqed.org/quest/2011/05/19/geological-outings-around-the-bay-ring-mountain/&quot; rel=&quot;nofollow&quot;&gt;watermelon seed theory&lt;/a&gt; . The general idea being that the compression in a subduction zone managed to eject these rocks back up and out of depth by a process like squeezing (and shooting) a wet watermelon seed between your fingers. &lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-05-02T19:17:23.633" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="729" PostTypeId="2" ParentId="400" CreationDate="2014-05-02T19:21:26.450" Score="9" Body="&lt;p&gt;The Dust Bowl was caused by farmers tilling up too much soil. However, there were also other factors. Weather also played a key role. Because there were several years of drought, and farmers had plowed up so much ground, when high winds came along the soil was blown off the ground, and the rest is history. This became somewhat of a vicious circle: no crops grew and so the dust could not be controlled.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as it happening again... Yes, I suppose it could and on a large scale, but run for cover. Because there would be some other very serious issues. Its occurrence would likely mean that there was little to no water available for irrigation. If that were the case, then I can not imagine how people would be responding to it.&lt;/p&gt;&#xA;" OwnerUserId="342" LastEditorUserId="94" LastEditDate="2014-06-25T05:26:30.960" LastActivityDate="2014-06-25T05:26:30.960" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="730" PostTypeId="2" ParentId="724" CreationDate="2014-05-02T20:09:10.100" Score="23" Body="&lt;p&gt;First, to describe El Niño as a Pacific Ocean event seems overly simplistic. The effects of El Niño are felt worldwide as can be seemed by a principal component (EOF) analysis (e.g., &lt;a href=&quot;http://dx.doi.org/10.1175/1520-0442%282002%29015%3C2205%3aTABTIO%3E2.0.CO;2&quot;&gt;Alexander et al., 2002&lt;/a&gt;). Also, using the term &quot;El Niño&quot; to describe the entire oscillation (ENSO, El Niño Southern oscillation) can lead to confusions as the term &quot;El Niño&quot; corresponds to one of the phases of the oscillation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The size of the Pacific Ocean and the lack of equatorial constraints makes it a prime candidate for large oceanic fluctuations such as ENSO. The large distance between the western and eastern sides of the basin allows for a more dynamic equilibrium with the presence of large scale waves (Kelvin and Rossby; e.g., &lt;a href=&quot;http://dx.doi.org/10.1175/1520-0442%281997%29010%3C1690%3aORWDAT%3E2.0.CO;2&quot;&gt;Kirtman, 1997&lt;/a&gt;). This equilibrium can be altered by external (atmospheric) forcing resulting in the different modes of oscillation of ENSO.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apart from that, there are a number of significant modes of oscillations (see &lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/climateindices/list/&quot;&gt;http://www.esrl.noaa.gov/psd/data/climateindices/list/&lt;/a&gt; for a very good list) that occur in basins outside the Pacific ocean. A good example is the North Atlantic Oscillation (NAO; &lt;a href=&quot;http://dx.doi.org/10.1126/science.269.5224.676&quot;&gt;Hurrel [1985, Science]&lt;/a&gt;; &lt;a href=&quot;http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.shtml&quot;&gt;http://www.cpc.ncep.noaa.gov/products/precip/CWlink/pna/nao.shtml&lt;/a&gt;) that affects not only the North Atlantic but also the climate of Europe and North America.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other examples of modes of climate variability include the Pacific Decadal Oscillation (PDO; &lt;a href=&quot;http://dx.doi.org/10.1175/1520-0442%281997%29010%3C1004%3aELIV%3E2.0.CO;2&quot;&gt;Zhang et al., 1997&lt;/a&gt;), the Atlantic Multidecadal Oscillation (AMO; &lt;a href=&quot;http://dx.doi.org/10.1038/367723a0&quot;&gt;Schlesinger &amp;amp; Ramankutty, 1994&lt;/a&gt;), or the Arctic Oscillation (AO; &lt;a href=&quot;http://dx.doi.org/10.1029/98GL00950&quot;&gt;Thompson &amp;amp; Wallace, 1998&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2014-05-07T15:22:36.683" LastActivityDate="2014-05-07T15:22:36.683" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="731" PostTypeId="2" ParentId="725" CreationDate="2014-05-02T20:18:08.147" Score="15" Body="&lt;p&gt;Earthquake epicenters are located using triangulation, this is possible once seismograms of the earthquake - coming from at least three locations - have been analyzed properly. Here is a good explanation on a site for seismology students at Michigan Tech which takes its seismogram illustrations from Bolt's textbook on earthquakes (1978). Read this page and you will have a good explanation of how seismologists determine the location of an earthquake epicenter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.geo.mtu.edu/UPSeis/locating.html&quot;&gt;How Do I Locate That Earthquake's Epicenter?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorUserId="178" LastEditDate="2014-05-03T06:04:11.953" LastActivityDate="2014-05-03T06:04:11.953" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="732" PostTypeId="2" ParentId="707" CreationDate="2014-05-02T21:07:20.560" Score="4" Body="&lt;p&gt;It is also challenging to get clouds, rain etc. right in weather forecasts. Compared to climate applications the advantage in weather forecasts is that cloud information from the initial conditions can improve the cloud representation in the model. Unfortunately that information does not last that long in the model due to the limited lifetimes of clouds. Nevertheless, for short-term forecasts assimilation of satellite and radar data can favor clouds in numerical weather prediction, which is not possible in climate modeling.&lt;/p&gt;&#xA;" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2014-05-03T09:36:21.027" LastActivityDate="2014-05-03T09:36:21.027" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="733" PostTypeId="1" AcceptedAnswerId="769" CreationDate="2014-05-03T01:14:45.983" Score="12" ViewCount="1302" Body="&lt;p&gt;How do we know that graptolites were pelagic, and not benthic, creatures? I understand it has something to do with their being found in black shale, but I'm not sure why that is particularly relevant.&lt;/p&gt;&#xA;" OwnerUserId="365" LastEditorUserId="6467" LastEditDate="2018-08-06T03:31:24.897" LastActivityDate="2018-08-06T03:31:24.897" Title="How do we know graptolites were pelagic?" Tags="|paleontology|graptolites|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="734" PostTypeId="2" ParentId="676" CreationDate="2014-05-03T01:38:05.297" Score="11" Body="&lt;p&gt;Good question!  I'll lay out the prevalent idea, originally (I think) put forward by &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/RG016i004p00621/full&quot;&gt;Sykes, 1978&lt;/a&gt; and supported by a large body of subsequent work by many authors. There are other models, however.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the most general sense: Intra-plate faulting is due to old, pre-existing weaknesses that are reactivated due to the plate interiors being very close to critically stressed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, they're weak points in the interior of the plate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, we don't fully understand why some old fault zones get reactivated while others in the same orientation don't.  (It probably has a lot to do with pore pressure and fluid movement at depth.) There's a lot we don't completely understand about intra-plate earthquakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, please don't use the term &quot;fault line&quot;. It offends my geologic sensibilities! :)  (Faults are 2D surfaces, not lines, thus the nitpicky objection.)&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Most of the crust is close to being critically stressed (breaking)&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;There's a lot of evidence that the continental crust everywhere is close to being critically stressed -- in other words, failing in an earthquake.  (e.g. see the various &lt;a href=&quot;http://geology.gsapubs.org/content/28/5/399.short&quot;&gt;Townend and Zoback&lt;/a&gt; papers.) The crust isn't just critically stressed near the plate boundaries, but also away from them. This may also be true for oceanic crust, but we don't have as much data there.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another way of saying this is that the plates are being pushed along as hard as they can without crumpling.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically, this is why things like building a dam or deep fluid injection trigger small earthquakes.  The crust is already close to failure, so adding load or increasing pore pressure often triggers small fractures.  (However, these sort of things can't trigger a major earthquake unless they're on an already active fault.  You need continuous slip along a &lt;em&gt;very&lt;/em&gt; large surface for a large earthquake.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The plates being critically stressed is actually is what we'd expect. We see deformation at plate boundaries whenever they collide. Therefore, we know that the stresses driving the plates are greater than the &quot;breaking&quot; strength of the crust.  Because stresses from a collision at the boundary will be transmitted to the interior, it intuitively makes sense that the interiors should be close to, but just below (otherwise they'd be deforming), the failure threshold. (For the complete argument, see &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0040195101000919&quot;&gt;Zoback and Townend, 2001&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Continental crust is full of old zones of weakness&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The continents are very old. Much older than the oceanic crust. The continents are like rafts that keep bumping into each other. Therefore, they have lots of &quot;scars&quot; (i.e. old fault zones).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's a saying in structural geology: &quot;once a weakness, always a weakness&quot;. Fault zones are typically much weaker than the crust around them.  Once a fault breaks through, it tends to be a permanent weakness that will be reactivated even if it's not in a perfectly favorable orientation.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Critically stressed crust + weak zones --&gt; intra-plate earthquakes.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;But why don't we see activity on all old fault zones?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Short answer, we don't really know.  It probably has a lot to do with pore pressure and fluid movement.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some old fault zones have intra-plate earthquakes, while others don't, even if they're in the same orientation.  Pore pressure plays a &lt;em&gt;huge&lt;/em&gt; role in faulting (it make rocks much easier to break).  There's a lot of speculation that active intra-plate fault zones may have more fluids at depth, though explaining why is difficult.&lt;/p&gt;&#xA;" OwnerUserId="12" LastEditorUserId="12" LastEditDate="2014-05-03T01:44:53.513" LastActivityDate="2014-05-03T01:44:53.513" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="735" PostTypeId="2" ParentId="733" CreationDate="2014-05-03T01:59:06.750" Score="14" Body="&lt;p&gt;Basically, we know they were likely pelagic creatures because we find their fossils at essentially all water depths.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If they were benthic creatures, we'd expect their fossils to be limited to a set range of paleo water depths.  It's unlikely that a single benthic (i.e. living on the seabed) marine organism could live in both shallow water and ultra-deep water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, for pelagic (i.e. floating or free-swimming) creatures, we'd expect to find their fossils at a huge range of paleo water depths because they live &lt;em&gt;in&lt;/em&gt; the water column and don't care where the bottom is.&lt;/p&gt;&#xA;" OwnerUserId="12" LastActivityDate="2014-05-03T01:59:06.750" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="736" PostTypeId="1" AcceptedAnswerId="738" CreationDate="2014-05-03T09:49:51.437" Score="21" ViewCount="5849" Body="&lt;p&gt;From my current understanding, Earth's atmosphere and air are held by the balance of two forces: 1. Earth's gravity and 2. Air pressure from air out to space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is my understanding correct?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/B5aNz.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, do these two forces always stay the same? If they are not the same, have the earth lost its air into space? And if so by how much each year?&lt;/p&gt;&#xA;" OwnerUserId="132" LastEditorUserId="64" LastEditDate="2014-05-06T03:56:35.257" LastActivityDate="2014-05-06T03:56:35.257" Title="Does Earth's air leak into space over time?" Tags="|atmosphere|meteorology|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="738" PostTypeId="2" ParentId="736" CreationDate="2014-05-03T14:58:29.123" Score="24" Body="&lt;p&gt;Earth's atmosphere &lt;em&gt;does&lt;/em&gt; escape over time, albeit very slowly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The distribution of kinetic energies of molecules in a gas obeys (more or less) a &lt;a href=&quot;http://en.wikipedia.org/wiki/Maxwell%E2%80%93Boltzmann_distribution&quot;&gt;Maxwell-Boltzmann distribution&lt;/a&gt;. Notice that the graph is asymptotic, so in a suitably large population of gas molecules, there is a non-zero probability that some of those molecules will have a an arbitrarily large kinetic energy. This implies that in the population of gas molecules constituting Earth's atmosphere, some of them will have kinetic energy such that their velocity exceeds the Earth's &lt;a href=&quot;http://en.wikipedia.org/wiki/Escape_velocity&quot;&gt;escape velocity&lt;/a&gt; and provided that their paths are oriented away from any obstacles (including the Earth's surface itself) and they don't collide with anything, those molecules can escape. On average, only a small number of molecules will actually achieve all these conditions. The end result is that atmosphere does indeed escape, but the effect is tiny - only on the order of grams per second due to the process described above &lt;a href=&quot;http://www.scientificamerican.com/article/how-planets-lose-their-atmospheres/&quot;&gt;according to this article I found&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is not the only process responsible however, phenomena like the solar wind also have a role in liberating gas molecules from the Earth's atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The effect is much more pronounced on other rocky planets in the Solar system, for example Mercury has very little atmosphere due to it i) being extremely hot and ii) being bombarded by highly energetic particles from the sun much more than we are. Similarly, Mars has a predominantly carbon dioxide atmosphere that is thought to have been much thicker in the past than it is now, and therefore must have escaped somehow (assuming you don't believe stories like &lt;a href=&quot;http://en.wikipedia.org/wiki/Total_Recall_%281990_film%29&quot;&gt;Total Recall&lt;/a&gt; where the atmosphere is intentionally held captive ;) - although in fact the Martian atmosphere does condense at the poles leading to a significant amount of atmospheric agitation with the changing of the seasons)&lt;/p&gt;&#xA;" OwnerUserId="368" LastActivityDate="2014-05-03T14:58:29.123" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="739" PostTypeId="5" CreationDate="2014-05-03T17:13:34.310" Score="0" Body="&lt;p&gt;&lt;strong&gt;Asking homework questions&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You need to do your homework yourself, to learn anything from it. The Earth Science community won't just do your work for you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For asking questions related to homework please consider:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Show that what you have attempted prior asking.&lt;/li&gt;&#xA;&lt;li&gt;Do not just copy past your assignment, ask a specific question about it instead.&lt;/li&gt;&#xA;&lt;li&gt;Add the homework tag to make transparent that the question is about homework.&lt;/li&gt;&#xA;&lt;li&gt;Check with your teacher / school whether it's ok to ask for help online and to post the problem on a public site.&lt;/li&gt;&#xA;&lt;li&gt;Try to formulate your question so that it is useful for people who do not have this homework assignment.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Answering and detecting homework questions&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For answering homework related questions please consider:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Do not provide the complete solution for the homework assignment, instead help the asker to find the solution alone. &lt;/li&gt;&#xA;&lt;li&gt;Make clear in the answer that it is help for homework and therefore only gives some hints.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;If you see questions which are about homework but miss to say so: Add the homework tag and drop a comment to the asker.&lt;/p&gt;&#xA;" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2014-05-03T17:16:17.800" LastActivityDate="2014-05-03T17:16:17.800" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="740" PostTypeId="4" CreationDate="2014-05-03T17:13:34.310" Score="0" Body="Question asked to solve homework assignments. Questions and answers should be formulated with special care. Students need to do their work themselves; the Earth Science community may help, but will not do the actual work." OwnerUserId="124" LastEditorUserId="64" LastEditDate="2014-05-03T17:20:23.943" LastActivityDate="2014-05-03T17:20:23.943" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="741" PostTypeId="2" ParentId="736" CreationDate="2014-05-03T17:15:39.367" Score="15" Body="&lt;p&gt;The balance of the two forces you mention (gravity and the pressure gradient force) is called &lt;em&gt;hydrostatic balance&lt;/em&gt; and is given by the equation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\dfrac{\partial p}{\partial z} = -\rho g$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This holds for the large scale atmosphere but commonly invalid in the troposphere at the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Mesoscale&quot;&gt;mesoscale&lt;/a&gt; where regions of large vertical motion are present (cyclones, thunderstorms, forced lifting, etc).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Below the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Turbopause&quot;&gt;turbopause&lt;/a&gt; (~100 km) the atmosphere is well mixed and is relatively homogeneous in its chemical makeup.  Above the turbopause the atmosphere becomes heterogeneous and stratifies into layers with the heavier elements lower and the light elements higher.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tow W's answer explains the escape methods well, and I wont recap them here.  I'll just add that due to the atmospheric composition above the turbopause, we tend to lose the lighter elements to space such as hydrogen and helium more than the heaver ones.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-05-03T17:15:39.367" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="742" PostTypeId="5" CreationDate="2014-05-03T18:03:56.637" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-05-03T18:03:56.637" LastActivityDate="2014-05-03T18:03:56.637" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="743" PostTypeId="4" CreationDate="2014-05-03T18:03:56.637" Score="0" Body="Questions about freely available data." OwnerUserId="124" LastEditorUserId="124" LastEditDate="2014-05-04T00:37:31.743" LastActivityDate="2014-05-04T00:37:31.743" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="744" PostTypeId="5" CreationDate="2014-05-03T18:21:31.240" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-05-03T18:21:31.240" LastActivityDate="2014-05-03T18:21:31.240" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="745" PostTypeId="4" CreationDate="2014-05-03T18:21:31.240" Score="0" Body="Questions about changes of the climate system, including questions about global warming." OwnerUserId="124" LastEditorUserId="20" LastEditDate="2014-05-03T20:43:34.580" LastActivityDate="2014-05-03T20:43:34.580" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="746" PostTypeId="5" CreationDate="2014-05-03T21:44:37.540" Score="0" Body="&lt;p&gt;Prominent remote sensing methods use electromagnetic and acoustic waves to measure properties at a distant location.&lt;/p&gt;&#xA;" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2014-05-04T01:09:13.177" LastActivityDate="2014-05-04T01:09:13.177" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="747" PostTypeId="4" CreationDate="2014-05-03T21:44:37.540" Score="0" Body="Questions about measurements which are taken from remote locations / are not taken in situ." OwnerUserId="124" LastEditorUserId="20" LastEditDate="2014-05-04T01:09:06.613" LastActivityDate="2014-05-04T01:09:06.613" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="748" PostTypeId="2" ParentId="402" CreationDate="2014-05-03T23:18:30.267" Score="13" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is it true that Earth's outercore rotates in the opposite direction to Earth's inner-core?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No. You misread a badly written for-the-masses science article. The article summary is at best rather confusing and misleading. It invites a reader to misinterpret what's going on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what's really going on? It's simple, conceptually. The mantle, outer core, and inner core all rotate in more or less the same direction and at more or less the same rate. However, because outer core is liquid, there exists a possibility for the mantle, outer core, and inner core to exhibit slightly different rotation rates (and perhaps even rotation axes). That's apparently what is happening inside the Earth. The mantle and crust make one rotation per sidereal day. The inner core currently rotates a tiny, tiny bit faster than that, while the outer core rotates a tiny, tiny bit slower than that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This means that when viewed from the perspective of an Earth-fixed observer, the outer core currently appears to be rotating a tiny, tiny bit westward and the inner core currently appears to be rotating a tiny, tiny bit eastward. It's a matter of perhaps confusing perspective. When viewed from an inertial perspective, the mantle, outer core, and inner core are all rotating more or less synchronously.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;When you read one of those science-for-the-masses type articles, it's a good idea to jump to the underlying journal article. In this case, you should try reading &lt;a href=&quot;http://www.pnas.org/content/110/40/15914.long&quot;&gt;Livermore, Hollerbach, and Jackson, &quot;Electromagnetically driven westward drift and inner-core superrotation in Earth’s core&quot;, PNAS 110:40 (2013)&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-05-03T23:18:30.267" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="749" PostTypeId="2" ParentId="251" CreationDate="2014-05-04T03:52:55.670" Score="14" Body="&lt;p&gt;The equation of motion for a fluid parcel in the atmosphere (in Cartesian space) is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\dfrac{D\mathbf u}{Dt} = -\dfrac{1}{\rho}\nabla p-2 \mathbf \Omega \times \mathbf u + \mathbf g + \mathbf F,$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\mathbf u$ is the wind, $\rho$ is density, $p$ is pressure, $\mathbf\Omega$ is the angular velocity of the Earth, $\mathbf g$ is gravity and $\mathbf F$ is friction.  The derivative is a material derivative (Lagrangian perspective) where&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\dfrac{D\varphi}{Dt} = \dfrac{\partial\varphi}{\partial t} + \mathbf u\cdot\nabla\varphi.$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a non-dimensional number called the Rossby number ($Ro$) that determines when a flow behaves geostrophically.  This number is given by&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$Ro = {U\over fL},$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $U$ is a velocity scale, $L$ is a length scale and $f$ is the Coriolis parameter ($f=2\Omega\sin\phi$, $\Omega = 7.2921 \times 10^{-5}\ \text{s}^{-1}$, and $\phi$ is latitude).  When $Ro &amp;lt;&amp;lt; 1$, the flow exhibits geostrophic balance.  This occurs when $L$ becomes large, which it does as the storm grows.  When I say the flow is geostrophic, what I really mean is that the net acceleration of a parcel is small.  In a tropical cyclone the isobars are roughly circular and this curvature gives rise to the gradient wind balance.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The gradient wind is the balance of the pressure gradient force, Coriolis force and centripetal acceleration.  In this flow, just as in geostrophic flow, the wind will follow the isobars, flowing cyclonically around the center of low pressure, though slower than a geostrphic flow with the same pressure gradient.  Close to the ocean surface friction plays a role, and for the near surface winds the friction will cause the wind to be slightly deflected toward low pressure, or inward across the isobars.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Close to the center of the storm, in and near the eyewall, the length scale $L$ is reduced and the Coriolis force places a smaller role.  Here the flow attains cyclostrophic balance -- a balance between centrifugal and pressure gradient forces.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The gradient and cyclostrophic balances explain the wind rotating around the storm and surface friction will give a radially inward component at low levels, advecting angular momentum toward the center of the storm.  Convection in the eyewall will lift air to the tropopause where it will flow anti-cyclonically (due to the thermal wind) away from the storm before subsiding.  The core of the storm is warm and the air there is subsiding, creating the cloud free eye. The flows around the storm are balanced flows and the flow inward/upward/outward/downward is a thermodynamic carnot engine.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This gives us a fairly stable setup and this is why once a tropical storm forms it tends to persist rather than tear itself apart.  The key to sustaining this balance is a warm ocean surface and weak vertical windshear.  If you take away the warm ocean the storm will start to spin down and if you have strong shear you will disconnect the lower and upper level circulations and the storm will weaken.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2014-05-21T21:35:00.300" LastActivityDate="2014-05-21T21:35:00.300" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="751" PostTypeId="1" AcceptedAnswerId="752" CreationDate="2014-05-04T03:57:38.443" Score="1" ViewCount="177" Body="&lt;p&gt;Realize that comparing planets is hard, but is Earth really that unique?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More to the point, if everything say 20-km below sea-level up into the exosphere disappeared (and the moon too) - what would be left to differentiate Earth from other planets?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/6EcMN.jpg&quot; alt=&quot;enter image description here&quot;&gt; &lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="284" LastEditDate="2014-05-04T18:35:24.730" LastActivityDate="2014-05-04T18:40:21.897" Title="Is the majority of Earth not unique?" Tags="|planetary-science|rare-earth|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="752" PostTypeId="2" ParentId="751" CreationDate="2014-05-04T04:25:15.677" Score="8" Body="&lt;p&gt;Most notably, a moving Lithosphere. Shaving off the surface 20km (Lithosphere is~120km) would not stop plate tectonics. What makes Earth's surface so different is that it has a constant cycling of lithosphere; Dead planets are forced to keep surface scars caused by major impacts and weathering. To this date, we have not found another example of plate tectonics, though our ability to confirm this on other planetary bodies is limited. &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="23" LastEditDate="2014-05-04T18:40:21.897" LastActivityDate="2014-05-04T18:40:21.897" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="754" PostTypeId="1" AcceptedAnswerId="755" CreationDate="2014-05-04T05:18:28.903" Score="12" ViewCount="271" Body="&lt;p&gt;Bit puzzled why it appears that seismic travel times from one location to another appears to just be a function of the distance, and not any other factors. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ndo4M.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Do seismic travel times from one location to another differ based on factors other than distance?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="32" LastEditDate="2014-05-04T05:28:00.190" LastActivityDate="2014-05-04T05:43:06.117" Title="Do seismic travel times from one location to another differ based on factors other than distance?" Tags="|geophysics|earthquakes|seismology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="755" PostTypeId="2" ParentId="754" CreationDate="2014-05-04T05:43:06.117" Score="9" Body="&lt;p&gt;&lt;strong&gt;Yes&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The biggest controlling factors are:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Distance&lt;/li&gt;&#xA;&lt;li&gt;Velocity Model&lt;/li&gt;&#xA;&lt;li&gt;Composition (though velocity model and composition are related)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I believe you understand the first factor, so I will focus on the other two. The most common &lt;strong&gt;GLOBAL&lt;/strong&gt; velocity model is PREM, which is depicted below(&lt;a href=&quot;http://eqseis.geosc.psu.edu/~cammon/HTML/Classes/IntroQuakes/Notes/waves_and_interior.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image Source&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/IA8k1.gif&quot; alt=&quot;enter image description here&quot;&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Velocity models basically assume the internal P and S velocity structure of Earth. If the crust is thinner than average in the area where the source is, the arrival times will be faster than if the crust is thicker than average, though depending on the distance this could be negligible. This is because seismic waves travel faster in than they do in the crust, so the least time tends to involve travel through the mantle. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other controlling factor is composition, or in other words, heterogeneities within the earth. Depending on the composition the wave travels through, arrival times could be slower or faster. For example, imagine an interplate earthquake traveling through a subducting slab and into a seismometer: the arrival times are slower because the wave speed of lithosphere is slower than the wave speed of mantle. In fact, its these deviations from our velocity model predictions that help us find heterogeneity in the earth to begin with! This is essentially how we find our natural resources, though instead of using earthquakes as the source we use man made active seismic waves. &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-05-04T05:43:06.117" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="757" PostTypeId="1" AcceptedAnswerId="763" CreationDate="2014-05-04T17:46:47.463" Score="4" ViewCount="717" Body="&lt;p&gt;If &lt;a href=&quot;http://physicsworld.com/cws/article/news/2011/jul/19/radioactive-decay-accounts-for-half-of-earths-heat&quot; rel=&quot;nofollow noreferrer&quot;&gt;radioactive decay supplies only about half the Earth’s heat&lt;/a&gt;, what are the remaining sources of heat? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/t13tq.gif&quot; alt=&quot;GRAPHIC-1: Structure of the Earth, GRAPHIC-2: Geothermal Gradient, GRAPHIC-3: Temperature Gradient of Geothermal Gradient&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="284" LastEditDate="2014-05-06T00:50:43.693" LastActivityDate="2014-05-06T00:50:43.693" Title="What Keeps the Earth Cooking?" Tags="|geothermal-heat|" AnswerCount="2" CommentCount="13" ContentLicense="CC BY-SA 3.0" />
  <row Id="758" PostTypeId="5" CreationDate="2014-05-04T17:54:12.450" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-05-04T17:54:12.450" LastActivityDate="2014-05-04T17:54:12.450" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="759" PostTypeId="4" CreationDate="2014-05-04T17:54:12.450" Score="0" Body="Questions about using weather balloons and dropsondes to measure vertical profiles of the atmosphere" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2014-05-04T18:14:06.237" LastActivityDate="2014-05-04T18:14:06.237" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="761" PostTypeId="1" CreationDate="2014-05-04T18:46:45.737" Score="8" ViewCount="2356" Body="&lt;p&gt;I am looking for a few options of particle tracking for ocean modeling to try to do a comparison of different codes.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="39" LastEditDate="2014-05-07T07:30:00.333" LastActivityDate="2015-06-11T06:19:58.110" Title="What are some options for online and offline particle tracking in ocean models?" Tags="|ocean|oceanography|models|modelling|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="762" PostTypeId="1" CreationDate="2014-05-04T19:02:07.897" Score="35" ViewCount="3826" Body="&lt;p&gt;Water plays a crucial role in plate tectonics by easing the brittle and ductile deformation of the Earth's lithosphere. Water lowers the Mohr-Coulomb for brittle fractures. During ductile deformation, it lubricates different deformational regimes. This is also important for the deformation in the asthenosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition, water plays an important role in the formation of water-bearing minerals and the fluxing of melts, thereby substantially changing the rheology of the lithosphere and asthenosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/f7YJ7.gif&quot; alt=&quot;Water-bearing minerals of the mantle.&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, what would plate tectonics look like on a waterless Earth? Would it even work? Would there be different rates, or totally different processes taking over, similar to what is seen on adjacent solar system bodies?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;&#xA;Sources:&#xA;&lt;a href=&quot;http://adsabs.harvard.edu/abs/2001AGUFM.U21A..09S&quot; rel=&quot;nofollow noreferrer&quot;&gt;V.S. Solomatov. &lt;em&gt;The role of liquid water in maintaining plate tectonics and the regulation of surface temperature&lt;/em&gt;&lt;/a&gt;&#xA;&lt;br&gt;&#xA;See also:&#xA;&lt;a href=&quot;https://physics.stackexchange.com/questions/48318/plate-tectonics-and-water&quot;&gt;Plate tectonics and water&lt;/a&gt;&#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="23" LastEditorUserId="-1" LastEditDate="2017-04-13T12:40:15.470" LastActivityDate="2014-12-22T14:28:58.627" Title="How would plate tectonics differ if Earth had no water?" Tags="|plate-tectonics|hypothetical|water|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="763" PostTypeId="2" ParentId="757" CreationDate="2014-05-04T19:07:20.127" Score="6" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;If radioactive decay supplies only about half the Earth’s heat, what are the remaining sources of heat?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Mostly it is residual heat energy from when the Earth was very young. The biggest source came from the kinetic energy of all the bodies, big and small, that collided to form the Earth being converted to heat. The differentiation of the Earth added even more heat energy to the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to radioactive decay, the on-going freezing of the outer core material onto to the inner core adds a bit more heat to the system, but neither one compensates for heat transported through the mantle and crust and then out into space. Note that this heating from below is but a tiny portion of the overall energy budget for the Earth's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even the Earth's surface was very hot shortly after the formation and differentiation of the Earth. While the surface cooled quickly (geologically speaking), the interior has not. The key reason is that 2,890 km of rock makes for a fairly thick blanket.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-05-04T19:07:20.127" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="764" PostTypeId="2" ParentId="761" CreationDate="2014-05-04T20:21:29.777" Score="12" Body="&lt;p&gt;The main difference between online and offline trajectory calculation is that the online is implemented as part of the model, and the trajectories are part of the model output. Offline trajectory calculation is a separate piece of software that takes Eulerian model output fields as input and calculates the trajectories.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main advantage of online particle tracking is that the displacement of a particle or tracer can be evaluated every time step, no matter how small it is. As a result, you can obtain a true particle trajectory based on what model produces. The disadvantage of the online tracking is that the user needs to know the particle release location and time ahead of running the model. The models listed below (at least) support online Lagrangian trajectory calculation:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://hycom.org&quot;&gt;HYbrid Coordinate Ocean Model (HYCOM)&lt;/a&gt; is a hydrostatic, hybrid-coordinate ocean circulation model that has particle calculation built-in;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://mitgcm.org/&quot;&gt;MIT General Circulation Model (MITgcm)&lt;/a&gt; is a non-hydrostatic circulation model with many physical parameterization options and a single dynamical kernel for both the atmosphere and ocean;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://www.myroms.org&quot;&gt;Regional Ocean Modeling System (ROMS)&lt;/a&gt; is a hydrostatic, sigma-coordinate (terrain-following) ocean model with many physical parameterization options a large user community.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;On the other side, offline particle tracking can only use the Eulerian fields as often as they are output. Thus, there will be an error in the calculated trajectory depending on the frequency of the output. On the other side, the main advantage of offline calculation is that the user can experiment and play around with deployment locations, times, area of coverage etc., because trajectory calculation typically takes much less computational effort than the actual model. There are several options here:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://code.google.com/p/connectivity-modeling-system/&quot;&gt;Connectivity Modeling System (CMS)&lt;/a&gt; takes gridded NetCDF files as input and produces Lagrangian trajectory output. Can handle fields from various Arakawa-staggered grids, and may produce probabilistic trajectories, diffusivity specified by user (optional). Compatible with at least HYCOM and ROMS output.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://stockage.univ-brest.fr/~grima/Ariane/&quot;&gt;Ariane&lt;/a&gt; also takes gridded NetCDF files and is compativle with at least HYCOM, ROMS and NEMO models.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://tracmass.org/&quot;&gt;TRACMASS&lt;/a&gt; seems to be compatible with many circulation models. It also has a &lt;a href=&quot;https://github.com/kthyng/tracpy&quot;&gt;Python interface&lt;/a&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;All models and tools listed in this answer are freely available for download under different open source licenses.&lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2014-05-05T17:49:03.437" LastActivityDate="2014-05-05T17:49:03.437" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="765" PostTypeId="1" CreationDate="2014-05-04T20:38:05.553" Score="19" ViewCount="39333" Body="&lt;p&gt;What conversion functions exist to transfer precipitation forecast in mm to expected snowfall in cm? Simple rules of thumbs as well as more advanced methods would be of interest.&lt;/p&gt;&#xA;" OwnerUserId="124" LastActivityDate="2022-01-24T12:29:14.330" Title="Transfer precipitation forecast in mm to expected snowfall in cm" Tags="|meteorology|precipitation|snow|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="766" PostTypeId="2" ParentId="765" CreationDate="2014-05-04T22:32:22.357" Score="14" Body="&lt;p&gt;The snow density, which is the &amp;quot;conversion function&amp;quot; you are looking for, of fresh fallen snow varies with atmospheric conditions, vapour saturation and temperature since these parameters determine the snow grain morphology (See &lt;a href=&quot;http://www.its.caltech.edu/%7Eatomic/snowcrystals/primer/morphologydiagram.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;this figure from SnowCrystals.com&lt;/a&gt;; I leave it as a link for copyright reasons). Densities can vary from as low as &amp;lt; 100 kg m&lt;sup&gt;-3&lt;/sup&gt; for cold conditions to maybe &amp;gt; 400 kg m&lt;sup&gt;-3&lt;/sup&gt; for wet snow. This essentially cover the spectrum for a normal snow pack. If you, by your question, are thinking about weather services reporting how much snow will come from a snow fall it is by no means a an easy thing to predict since you may &amp;quot;know&amp;quot; the amount of precipitation from a model, but you will have more difficulties knowing the density of the fallen snow unless you devise a classification based on the atmospheric conditions during snow fall (based on snow crystal structure as in the figure). Hence for many purposes, the snow pack thickness is of little value and most will want the water equivalent of that snow, i.e. how much liquid precipitation it corresponds to.&lt;/p&gt;&#xA;&lt;p&gt;If snow is falling during drifting conditions, the density may become higher than the falling snow itself would have resulted in. This is because with wind drifting, snow crystals are reduced in size by crushing and can hence be more densely packed.&lt;/p&gt;&#xA;&lt;p&gt;With time the snow pack will densify due to metamorphic processes. This will cause the snow to decrease in thickness with time. But that is perhaps a different question since yours were about fresh snow.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="6298" LastEditDate="2022-01-24T12:29:14.330" LastActivityDate="2022-01-24T12:29:14.330" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="767" PostTypeId="1" AcceptedAnswerId="775" CreationDate="2014-05-04T23:38:04.087" Score="12" ViewCount="284" Body="&lt;p&gt;When reading older papers how should I interpret the use of &quot;Late Tertiary&quot; and &quot;Early Tertiary&quot;?  Would these periods equate to Paleogene and Neogene, or was there a different accepted boundary age between the Late and Early Tertiary?&lt;/p&gt;&#xA;" OwnerUserId="156" LastEditorUserId="87" LastEditDate="2014-05-05T16:35:51.697" LastActivityDate="2014-05-05T16:35:51.697" Title="How to interpret the use of late and early Tertiary from older literature?" Tags="|geology|geochronology|stratigraphy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="768" PostTypeId="2" ParentId="706" CreationDate="2014-05-05T00:35:00.360" Score="7" Body="&lt;p&gt;Biostratigraphy - observing which fossils were present in which stratigraphic units, and using minimally-deformed sequences to determine age order - gives us relative ages of fossils.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Absolute ages, however, rely on geochemical chronometers: just like dating the reversals in the Earth's magnetic polarity by establishing how old the oceanic crust that records them, or working out when volcanic eruptions happened. &lt;em&gt;Which&lt;/em&gt; chronometer you use depends on exactly what you're working with, but what they all have in common is that they use radiometric dating: the &quot;ticking clock&quot; is radioactive decay, which proceeds according to a radioactive isotope's half-life. Radiocarbon dating can be used for the most recent of these, but the example I'm going to use is uranium-series decay in corals - even though it's a weird one, because unlike most systems it doesn't measure parent-daughter ratios, but rather how closely the system has approached &lt;em&gt;secular equilibrium&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Uranium is soluble in natural waters at conditions found on the Earth's surface; thorium, however, is not; so corals (predominantly calcium carbonate), while growing, continuously incorporate uranium but &lt;em&gt;not&lt;/em&gt; thorium. Once they stop growing, this is no longer true - the amount of uranium incorporated in the coral is now fixed. Uranium-234 decays to give thorium-230, which is itself radioactive, with a significantly shorter half-life. At secular equilibrium, the rate of thorium-230 production (from uranium-234 decay) equals the rate of thorium-230 decay, so &lt;sup&gt;230&lt;/sup&gt;Th reaches steady state. Provided secular equilibrium has not been reached and the concentration of &lt;sup&gt;238&lt;/sup&gt;U (&lt;sup&gt;234&lt;/sup&gt;U's parent) is also known, it is possible to calculate how long ago the coral stopped incorporating new uranium - became a &quot;closed system&quot;. The mathematics of U-series secular equilibria are well understood but somewhat tedious, and are freely available.&lt;/p&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-05-05T00:35:00.360" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="769" PostTypeId="2" ParentId="733" CreationDate="2014-05-05T00:55:09.503" Score="10" Body="&lt;p&gt;You particularly mention black shale: the reason it's important is that shale is composed of mud- and silt-sized particles, so to form requires an environment with very slow-moving water such that the particles can effectively sediment out - and such that larger clastic material has already been deposited. The higher the water flow rates, the larger the sediment particles that can be carried: so continental margins frequently have significant sand deposits, whereas quicker-moving mountain streams can move pebbles (and fast-moving floods can manage boulders!). Thus black shales represent deep-sea environments, far from continental margins and related clastic input via rivers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fossil distribution is a very good guide to faunal habitat. There are trilobite species found in Scotland and Canada and nowhere else; trilobite fossils are found only in shallow environments (and some were not just benthic but infaunal, i.e. lived in the mud&lt;sup&gt;1&lt;/sup&gt;) and show no evidence of being able to swim, let alone long distances, so this fossil distribution is taken as evidence of proximity of these continental plates in the geologic past.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nautiloids, on the other hand, are known - from modern examples - to be pelagic rather than benthic, and to require a pretty narrow temperature range. Nonetheless, in spite of their very specific requirements, nautiloid fossils are found in deep-sea sediments from regions that could not possibly have been that warm (as evidenced by e.g. ice-rafted debris indicating local presence of icebergs). As a pelagic species, their remains are widespread because they are carried through the ocean, only gradually settling out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Graptolites are also ubiquitous: they are found in sediments from every palaeodepth &lt;a href=&quot;https://en.wikipedia.org/wiki/Graptolite#Preservation&quot;&gt;though (their preservation potential varies between different sediment types&lt;/a&gt;). And especially, as you note, they are found in black shales - deep-sea/abyssal plain sediments. Given what we know about the abyssal plain (poor bottom circulation, low oxygen) and the likely requirements of graptolites as plankton, it's evident that to be found in these sediments - as well as, more rarely, in shallow limestones - the only possible explanation is that they were a pelagic species. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt; And on a complete tangent: the lenses of trilobite eyes are made out of calcium carbonate, oriented along the single optic axis that didn't result in them seeing double. Now, most infaunal trilobites were blind: no point in being able to see if you live in an environment with no light. However, &lt;a href=&quot;https://en.wikipedia.org/wiki/Asaphus_kowalewskii&quot;&gt;&lt;em&gt;some of them had eyes on stalks.&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-05-05T00:55:09.503" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="770" PostTypeId="1" AcceptedAnswerId="774" CreationDate="2014-05-05T02:04:14.887" Score="14" ViewCount="1047" Body="&lt;p&gt;Appears that the answer is that it is highly likely that the water that the ringwoodite minerals point to is an &quot;ocean's worth&quot; of water, not a true subterranean ocean.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Do ringwoodite minerals point to an &quot;ocean's worth&quot; of water, or a true subterranean ocean?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/7K3AD.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="284" LastEditDate="2014-05-05T02:15:26.560" LastActivityDate="2014-05-05T06:47:22.183" Title="Do ringwoodite minerals point to an &quot;ocean's worth&quot; of water, or a true subterranean ocean?" Tags="|ocean|groundwater|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="772" PostTypeId="2" ParentId="245" CreationDate="2014-05-05T03:51:51.407" Score="4" Body="&lt;p&gt;While it is not about butterflies, scientist have found weather in the United States and Noctilucent Clouds in Antarctica to be linked across thousands of miles.&lt;/p&gt;&#xA;&lt;p&gt;Here are a few excerpts of what they have found:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;New data from NASA's AIM spacecraft have revealed &amp;quot;teleconnections&amp;quot; in Earth's atmosphere that stretch all the way from the North Pole to the South Pole and back again, linking weather and climate more closely than simple geography would suggest.&lt;/p&gt;&#xA;&lt;p&gt;For example, says Cora Randall, AIM science team member and Chair of the Dept. of Atmospheric and Oceanic Sciences at the University of Colorado, &amp;quot;we have found that the winter air temperature in Indianapolis, Indiana, is well correlated with the frequency of noctilucent clouds over Antarctica.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It demonstrates how apparently unrelated events can in fact be related to each other.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://science.nasa.gov/science-news/science-at-nasa/2014/16apr_teleconnections/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here is the full article to read.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="382" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-05-05T03:51:51.407" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="773" PostTypeId="1" CreationDate="2014-05-05T04:01:08.037" Score="16" ViewCount="69325" Body="&lt;p&gt;The standard representation of the rock cycle usually looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/1qxMW.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does each stage of the rock cycle currently balance? That is, are the various processes in dynamic equilibrium, so that the proportions of the different rock types remain constant?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the processes are not in equilibrium, which types of rock are currently increasing in overall prevalence, and which are decreasing?&lt;/p&gt;&#xA;" OwnerUserId="132" LastEditorDisplayName="user12525" LastEditDate="2019-04-27T09:35:21.783" LastActivityDate="2019-10-18T16:09:25.367" Title="Are the processes of the rock cycle currently in dynamic equilibrium?" Tags="|geology|rocks|petrology|geodynamics|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="774" PostTypeId="2" ParentId="770" CreationDate="2014-05-05T06:47:22.183" Score="15" Body="&lt;p&gt;A &amp;quot;true subterranean ocean&amp;quot; would suggest a vast amount of liquid water in the mantle. This is most probably not present, for which there are a number of clues.&lt;/p&gt;&#xA;&lt;p&gt;First of all, when looking at the temperature (~2000K) and pressure (~20GPa) in the transition zone and look at a phase diagram for water it is clear water can't exist as a liquid even though the temperature isn't visible in the diagram. The exact phase isn't clear, it could be a solid or a supercritical liquid.&#xA;&lt;img src=&quot;https://i.stack.imgur.com/0LHdA.gif&quot; alt=&quot;&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;A second clue is in seismology. Earthquakes produce two types of waves, P-type and S-type, of which only the first can propagate through liquids, see for example &lt;a href=&quot;http://www.iris.edu/hq/programs/education_and_outreach/animations/18&quot; rel=&quot;noreferrer&quot;&gt;this page&lt;/a&gt;. As a large body of liquid would produce a large shadow in seismic reflections, and these aren't well known (apart from the outer-core-shadow), it is unlikely there is much liquid water in the mantle.&lt;/p&gt;&#xA;&lt;p&gt;Also, note that the water in ringwoodite isn't present as water molecules, but as hydrogen and oxygen ions, according to wikipedia.&lt;/p&gt;&#xA;&lt;p&gt;Therefore, if there is indeed an ocean's worth of water present in the mantle transition zone, it will be there as a solid, which in my opinion can't be called a subterranean ocean.&lt;/p&gt;&#xA;&lt;p&gt;Phase diagram for water from: &lt;a href=&quot;http://www1.lsbu.ac.uk/water/phase.html&quot; rel=&quot;noreferrer&quot;&gt;http://www1.lsbu.ac.uk/water/phase.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="79" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-05-05T06:47:22.183" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="775" PostTypeId="2" ParentId="767" CreationDate="2014-05-05T07:17:32.847" Score="10" Body="&lt;p&gt;I think this is very hard to answer this question as it is exactly this ambiguity that caused the &lt;a href=&quot;http://www.stratigraphy.org&quot;&gt;International Commission on Stratigraphy&lt;/a&gt; to discard the names &lt;a href=&quot;http://www.stratigraphy.org/bak/geowhen/stages/Tertiary.html&quot;&gt;Tertiary&lt;/a&gt; and &lt;a href=&quot;http://www.stratigraphy.org/bak/geowhen/stages/Quaternary.html&quot;&gt;Quaternary&lt;/a&gt; for there are no clear limits to these era's. For example, the name Quaternary was only introduced some 70 years after the name Tertiary (&lt;a href=&quot;http://www.stratigraphy.org/bak/geowhen/TQ.html&quot;&gt;source&lt;/a&gt;), and Neogene covered both the last part of the Tertiary as well as the Quaternary era (&lt;a href=&quot;http://wzar.unizar.es/isps/&quot;&gt;source&lt;/a&gt;), until in 2009 the Quaternary was reinstated as a period while at the same time redefining the boundary of the Pleistocene (&lt;a href=&quot;http://www.stratigraphy.org/images/Archive/ICS_AnnReport2009.pdf&quot;&gt;source&lt;/a&gt;), so interpretation should take into account when the article was written as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The meaning of Late and Early Tertiary is therefore dependent on the context, and is probably only safe to be interpreted as relative ages (unless exact ages are given, but in that case there is no question of interpretation), not well defined periods in time. It might help to look for articles by the same author or from the same year to see what the common interpretation was at that time. &lt;/p&gt;&#xA;" OwnerUserId="79" LastEditorUserId="79" LastEditDate="2014-05-05T09:40:33.907" LastActivityDate="2014-05-05T09:40:33.907" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="776" PostTypeId="2" ParentId="773" CreationDate="2014-05-05T07:31:15.507" Score="18" Body="&lt;p&gt;It's an interesting question, but in practice I think it's impossible to answer. It's very difficult to measure the rates of many of those processes, and the divisions between rock types can be quite ill-defined (for example, in &lt;a href=&quot;http://en.wikipedia.org/wiki/Migmatite&quot;&gt;migmatites&lt;/a&gt;). There's no scientific instrument we can point at a chunk of the earth which will tell us &quot;in this region, 29.4 megatons of sedimentary rock became metamorphic rock during the past year&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What we can say, at least, is that the global balance of these processes is not constant over time. For example, during the &lt;a href=&quot;http://en.wikipedia.org/wiki/Deccan_Traps&quot;&gt;Deccan Traps&lt;/a&gt; eruptions there was an increase in the rate of formation of igneous rock through solidification of magma.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The classic rock cycle diagram you posted probably encourages this kind of question, because it makes it look like a neat, closed system with well-defined boundaries and comparable quantities of each rock type. It's a very useful simplification for many purposes, but remember that these processes are occurring at or near the earth's surface. This whole system sits on top of the mantle (which is vast compared to the volume of crustal rock), and material is continually being passed between the two, so it's far from being a closed system.&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2014-05-05T08:10:07.137" LastActivityDate="2014-05-05T08:10:07.137" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="777" PostTypeId="2" ParentId="723" CreationDate="2014-05-05T08:36:14.323" Score="11" Body="&lt;p&gt;Fossil groundwater is water that has been trapped below the surface for several thousands of years. It is considered non-renewable as natural recharge on human timescales is practically zero. This is because the permeability/transmissivity of the overlying strata is very low.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, on geological timescales the aquifer will recharge as pumping the water out of the aquifer decreases the hydraulic head, and therefore increases the gradient over the aquitards sealing the aquifer. Therefore the recharge of the aquifer actually speeds up by withdrawing water, although probably not in amounts humans can profit from.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since you're asking about techniques to recharge, techniques similar to those used for shallower aquifers could be applied. In the Netherlands regeneration of groundwater is performed to decrease the stationary drawdown of the groundwater by the pumping which leads to damages for farmers. This is often performed by pumping surface water into the aquifer at some distance so the aquifer is recharges artificially and the groundwater table rises.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, recharge of these fossil water aquifers in arid areas such as the subtropics is probably infeasible, even though it would be technically possible.&lt;/p&gt;&#xA;" OwnerUserId="79" LastActivityDate="2014-05-05T08:36:14.323" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="778" PostTypeId="1" CreationDate="2014-05-05T09:50:35.473" Score="13" ViewCount="1036" Body="&lt;p&gt;When I studied earth science, a lecturer mentioned that one of the anomalies that earth science hasn’t been able to explain is a piece of crust in the USA.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This piece of crust appeared to match very well with the crust of another continent, if turned upside down, and didn’t match the surrounding crust in the USA.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can't find any information about this and I can't forget about it. Is there any basis for this claim?&lt;/p&gt;&#xA;" OwnerUserId="385" LastEditorUserId="20" LastEditDate="2015-09-12T22:54:26.903" LastActivityDate="2015-09-12T22:54:26.903" Title="Is there a piece of upside down foreign crust in the USA?" Tags="|geologic-layers|tectonics|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="780" PostTypeId="2" ParentId="778" CreationDate="2014-05-05T12:16:27.353" Score="15" Body="&lt;p&gt;Most probably, he was referring to the Brunswick Magnetic Anomaly: &lt;a href=&quot;http://www.geosociety.org/news/pr/2014/14-22.htm&quot;&gt;http://www.geosociety.org/news/pr/2014/14-22.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is an area of lower-than-normal magnetism present in North America in the Southwestern United States. Note that altough it COULD be a piece of Africa, it could also be caused by something else.&lt;/p&gt;&#xA;" OwnerUserId="386" LastActivityDate="2014-05-05T12:16:27.353" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="781" PostTypeId="2" ParentId="560" CreationDate="2014-05-05T14:18:55.523" Score="13" Body="&lt;p&gt;The &lt;a href=&quot;http://adsabs.harvard.edu/abs/2011AGUFM.U53E..06W&quot;&gt;2011 AGU poster&lt;/a&gt; has been cited once, by &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/jgrf.20137/abstract&quot;&gt;Burtin &lt;em&gt;et al&lt;/em&gt;. (2013)&lt;/a&gt;&lt;sup&gt;1&lt;/sup&gt;, who say in their abstract &lt;em&gt;... event activity was positively correlated with the precipitation intensity...&lt;/em&gt; -- but more importantly, in the body of the paper, this:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Furthermore, it has been argued that rainfall may affect the occurrence of earthquakes, either by downward fluid diffusion from the surface [e.g., Bollinger et al., 2007] or by erosional unloading of active faults [e.g., Wdowinski and Tsukanov, 2011], but these mechanisms require exceptional or very prolonged precipitation and they are likely to entail significant delays between the meteorological driver and seismic response of up to years. For&#xA;  these reasons, we also rule out rainfall-triggered seismicity as a possible source of the near-surface activity we have detected.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Note, however, that over the course of the study they recorded 29 events, of M&lt;sub&gt;l&lt;/sub&gt; 0.7–5.7.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meanwhile &lt;a href=&quot;http://link.springer.com/article/10.1134/S0742046312020078&quot;&gt;Sobolev &lt;em&gt;et al.&lt;/em&gt; (2012)&lt;/a&gt;&lt;sup&gt;2&lt;/sup&gt; - in a journal I &lt;em&gt;do&lt;/em&gt; trust - say in their abstract:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This study is concerned with the effects of powerful Pacific cyclones on the seismicity of Kamchatka, Japan, and the Philippines. We used complete seismological catalogs for these regions that span a few tens of years. It was found that the cyclones that originate from the western Pacific generally do not exert a significant triggering effect on the seismicity of these three regions, at least in the short term, during a few weeks. The ground motion generated by cyclones, which might be treated as a trigger, does not have amplitudes above those in the motion due to numerous local earthquakes of moderate magnitudes (∼4–5) and larger teleseismic earthquakes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The only two recent publications claiming any link at all between cyclones/extreme precipitation events and significant seismic activity (i.e. not &quot;minor&quot; landslips) are from sources I don't trust: &lt;a href=&quot;http://web.a.ebscohost.com/abstract?direct=true&amp;amp;profile=ehost&amp;amp;scope=site&amp;amp;authtype=crawler&amp;amp;jrnl=21568359&amp;amp;AN=90488281&amp;amp;h=sisqgNzOZmXChltlUYVlqEokXffERYXOnz7t5HcC%2fXF71R6OwQ6fpHR%2bH34eozExJ9sUQqsq2AFpsR7P2Egl%2bg%3d%3d&amp;amp;crl=c&quot;&gt;a 2013 paper&lt;/a&gt; in a journal I've never heard of (&lt;a href=&quot;http://www.scirp.org/journal/ijg/&quot;&gt;International Journal of Geosciences&lt;/a&gt;) before, and &lt;a href=&quot;http://www.nat-hazards-earth-syst-sci-discuss.net/2/935/2014/nhessd-2-935-2014.pdf&quot;&gt;a 2014 publication in &quot;Natural Hazards and Earth System Sciences Discussion&lt;/a&gt;. I'm dubious about them &lt;em&gt;not&lt;/em&gt; because they are open access but because I am concerned about methodology and sources.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While this mechanism was mentioned to me as plausible as an undergraduate at Cambridge in approximately 2012, the department's view seems to have shifted (per Burtin et al - Neils Hovius is very senior in the dept). The current evidence does not appear to support any short-term link between extreme weather events and significant seismic activity. Long-term links have not been ruled out but I have not found any substantiating evidence for such connections.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt; disclaimer: it turns out I know two of the coauthors, including one of the senior ones, personally.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;2&lt;/sup&gt; &lt;a href=&quot;http://www.maikonline.com/maik/showArticle.do?auid=VAH17QFXBD&quot;&gt;Original in Russian also available&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-05-05T14:18:55.523" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="782" PostTypeId="2" ParentId="565" CreationDate="2014-05-05T15:04:30.200" Score="4" Body="&lt;p&gt;&lt;strong&gt;Answer is no, Earth not an organism.&lt;/strong&gt; Key reason being that &lt;a href=&quot;http://en.wikipedia.org/wiki/Reproduction#Life_without_reproduction&quot; rel=&quot;nofollow&quot;&gt;life without reproduction&lt;/a&gt; is not life, and there is no logical proof that Earth reproduces using a type of reproduction never observed, or is proof that life does not require reproduction. &lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="284" LastEditDate="2014-05-05T15:37:21.123" LastActivityDate="2014-05-05T15:37:21.123" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="783" PostTypeId="1" AcceptedAnswerId="836" CreationDate="2014-05-05T16:00:08.460" Score="11" ViewCount="281" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Supervolcano&quot;&gt;Supervolcanos&lt;/a&gt; have occurred in the recent geological past, but not within the past 74,000 years. &lt;strong&gt;Is it possible to find the magma chambers with no previous history of supervolcanic activity that are likely to produce supervolcanos?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="284" LastEditDate="2014-05-06T00:52:11.370" LastActivityDate="2014-05-08T13:52:18.087" Title="Is it possible to find the magma chambers that produce supervolcanos?" Tags="|volcanology|volcanoes|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="784" PostTypeId="1" CreationDate="2014-05-05T16:20:44.063" Score="10" ViewCount="260" Body="&lt;p&gt;I have a dataset containing high frequency measurements of the hydraulic head at different locations in a 5x6km area. Also known are the precipitation, evaporation, and pumped discharges from a number of wells (unfortunately only monthly totals for the latter). Using the &lt;a href=&quot;http://www.kwrwater.nl/Menyanthes/&quot; rel=&quot;noreferrer&quot;&gt;Menyanthes&lt;/a&gt; software, timeseries analysis is performed returning the stationary drawdown at each location as a result of the groundwater withdrawal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A very schematic crosssection of the pumping wells and measurement wells is given below. The red lines indicate pumping wells, blue lines are some of measurement locations, in reality there are 10 pumping wells and some 40 measurement wells. The thick dotted lines are faults, hatched lines indicate an aquitard, while crosshatching indicates an aquiclude. I'm mainly interested in the top layer as that is where the drinking water is extracted from, but I included the deeper layers for completeness.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/anNRW.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the calculated drawdown at each location I want to calculate (or at least estimate) the transmissivity of each aquifer so I can hopefully tell a bit more about the resistance caused by the faults (by smeared out clay layers mostly). I know of the Thiem and Theis models (see for example &lt;a href=&quot;http://www.tandfonline.com/doi/abs/10.1080/02626669809492183#.U2e6cHV_sro&quot; rel=&quot;noreferrer&quot;&gt;this article&lt;/a&gt;) for the drawdown in equilibrium and fluctuating situations, but are there any other models around that might be helpful to determine the geohydrological properties of the different compartments?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I realise this question probably doesn't have a single conclusive answer, but I think it is relevant for this site anyway as it tries to compare the available models/equations for evaluation of a definitely on-topic problem.&lt;/p&gt;&#xA;" OwnerUserId="79" LastEditorUserId="79" LastEditDate="2014-05-05T17:30:15.280" LastActivityDate="2014-05-09T19:35:23.880" Title="How to determine the transmissivity of a system of rocks and faults from the stationary drawdown pattern?" Tags="|measurements|models|hydrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="785" PostTypeId="1" AcceptedAnswerId="787" CreationDate="2014-05-05T17:35:42.017" Score="13" ViewCount="1221" Body="&lt;p&gt;I was looking into the &lt;a href=&quot;http://discovertheodds.com/what-are-the-odds-of-being-struck-by-lightning/&quot; rel=&quot;noreferrer&quot;&gt;odds of getting hit by lightning&lt;/a&gt; and ran across this map:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/JV6Gx.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My first thought for this was due to a higher number of thunderstorms in Florida.  However, the map for that doesn't seem to line up:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/ywEin.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The midwest clearly has the highest concentration of thunderstorms, yet Florida is the leader in cloud-to-ground lightning.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question: Why does Florida get so much cloud-to-ground lighting, even though it doesn't have very many severe thunderstorms?&lt;/p&gt;&#xA;" OwnerUserId="330" LastEditorUserId="64" LastEditDate="2014-05-05T17:45:52.767" LastActivityDate="2014-05-05T17:45:52.767" Title="Cloud-to-ground lightning in Florida?" Tags="|meteorology|lightning|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="787" PostTypeId="2" ParentId="785" CreationDate="2014-05-05T17:45:06.437" Score="15" Body="&lt;p&gt;Your map of lighting tells you where thunderstorms occur.  Your second map of watches tells you where a subset of thunderstorms exhibiting severe threats (high winds, large hail or tornadoes).  The type of thunderstorms that frequent Florida are air-mass thunderstorms and generally will not warrant a severe thunderstorm watch.  The storms in the midwest that do get watches are typically of the supercell variety or associated with squall lines or bow echoes.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your thesis that &quot;The midwest clearly has the highest concentration of thunderstorms&quot; is incorrect.  What your data says is that the midwest has the highest concentration of thunderstorms producing severe weather threats.  This is not the same as concentration of thunderstorms.  All thunderstorms produce lightning (by definition), not all of them are severe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Convection in Florida is driven by the sea breeze and afternoon storms happen there like clockwork.  These storms produce lightning but no threats that would warrant a severe thunderstorm watch.  These storms last about 45-60 minutes and produce lightning.  This also makes Florida the lightning capital of the US, as the data in your question shows.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-05-05T17:45:06.437" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="788" PostTypeId="2" ParentId="757" CreationDate="2014-05-05T18:21:38.957" Score="4" Body="&lt;p&gt;This is an exciting topic of geophysics, because Earth's heat flow represents a classic question for earth science, heat source distribution is critical to modeling mantle convection, and because the application of geoneutrinos is cutting-edge experimental physics. The original publication reporting the use of KamLAND geoneutrino data was in Nature, and well worth reading. An online pdf is available here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://bama.ua.edu/~andreas/ps_files/NatureGeo1205.pdf&quot; rel=&quot;nofollow&quot;&gt;Partial radiogenic heat model for Earth revealed by geoneutrino measurements&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-05-05T18:21:38.957" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="789" PostTypeId="5" CreationDate="2014-05-05T18:22:43.917" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-05-05T18:22:43.917" LastActivityDate="2014-05-05T18:22:43.917" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="790" PostTypeId="4" CreationDate="2014-05-05T18:22:43.917" Score="0" Body="concerning the formation, behaviour and composition of this form of eruption (hot currents of gas and rock moving along or close to the Earth's surface)" OwnerUserId="105" LastEditorUserId="105" LastEditDate="2014-05-06T14:19:26.087" LastActivityDate="2014-05-06T14:19:26.087" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="791" PostTypeId="5" CreationDate="2014-05-05T18:24:54.027" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-05-05T18:24:54.027" LastActivityDate="2014-05-05T18:24:54.027" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="792" PostTypeId="4" CreationDate="2014-05-05T18:24:54.027" Score="0" Body="questions relating to solid-state recrystallisation of rocks, including (but not limited to) conditions, chemical reactions, and geobarometers and geothermometers " OwnerUserId="105" LastEditorUserId="105" LastEditDate="2014-05-06T14:19:10.657" LastActivityDate="2014-05-06T14:19:10.657" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="793" PostTypeId="1" AcceptedAnswerId="794" CreationDate="2014-05-06T03:24:48.073" Score="19" ViewCount="2993" Body="&lt;p&gt;According to the graph below, which appears to be &lt;a href=&quot;http://www.bbc.com/news/science-environment-22607522&quot; rel=&quot;noreferrer&quot;&gt;sourced from the US National Oceanic and Atmospheric Administration&lt;/a&gt;, more tornadoes happen late in the day - why is this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/DTSHb.gif&quot; alt=&quot;US tornadoes by month &amp;amp; time of day; shows warmer months and late day are the most like times for tornadoes.&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="64" LastEditDate="2014-05-06T03:28:39.633" LastActivityDate="2016-10-08T18:10:03.000" Title="Why do more tornadoes happen late in the day?" Tags="|meteorology|tornado|climatology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="794" PostTypeId="2" ParentId="793" CreationDate="2014-05-06T03:43:51.367" Score="17" Body="&lt;p&gt;There are two factors at work here:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Actual occurrence of tornadoes,&lt;/li&gt;&#xA;&lt;li&gt;Reports of tornadoes.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Tornadoes are primarily associated with supercell thunderstorms, though they can also be associated with landfalling tropical cyclones, squall lines and bow echoes.  Thunderstorms are favored in the afternoon to early evening hours as this is when integrated solar heating throughout the day has warmed the boundary layer enough to kickstart convection (through reaching the convective temperature or eroding the capping inversion).  Because of this, supercells are going to tend to initiate in the mid to late afternoon and if they produce tornadoes it will be in the timeframe maximized in your graph.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The tornado record is far from perfect and is based on verification of tornado damage.  That damage will only be surveyed if a potential tornado is reported or radar strongly suggested that one may have occurred.  A small tornado in the middle of nowhere from an unimpressive storm at night surely may exist, but a record of it may not.  This is also true of middle-of-nowhere tornadoes during the day, but those may have a slightly higher chance of being reported by a storm chaser.  No one smart chases at night.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-05-06T03:43:51.367" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="795" PostTypeId="1" AcceptedAnswerId="797" CreationDate="2014-05-06T03:47:32.603" Score="7" ViewCount="1100" Body="&lt;p&gt;Appears that a &lt;a href=&quot;http://www.geology.wisc.edu/~wiscsims/pdfs/Valley_NGeo2014.pdf&quot; rel=&quot;noreferrer&quot;&gt;4.4 billion-year-old crystal is oldest piece of Earth&lt;/a&gt;, and the crystal's chemistry -- specifically, the ratio of oxygen isotopes within it -- suggests that the temperatures on Earth 4.4 billion years ago would have supported liquid water, and therefore perhaps life; &lt;a href=&quot;http://en.wikipedia.org/wiki/Age_of_the_Earth&quot; rel=&quot;noreferrer&quot;&gt;Earth is 4.54 billion years old&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to this &lt;a href=&quot;http://xkcd.com/1194/&quot; rel=&quot;noreferrer&quot;&gt;xkcd comic&lt;/a&gt;, &quot;&lt;a href=&quot;http://www.explainxkcd.com/wiki/index.php/1194:_Stratigraphic_Record&quot; rel=&quot;noreferrer&quot;&gt;all the crust older than 3.5 billion years has been recycled into the mantle by subduction.&lt;/a&gt;&quot;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/jITFf.png&quot; alt=&quot;Stratigraphic Record - all the crust older than 3.5 billion years has been recycled into the mantle by subduction.&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Is it true that it is possible there is a roughly one billion years of Earth's history with water present that's unaccounted for, and if so, do we have any reason to believe we'll better understand this time in Earth's history?&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="284" LastEditDate="2014-05-06T03:55:22.370" LastActivityDate="2024-02-14T18:38:53.427" Title="Is a billion years of Earth's history missing?" Tags="|earth-history|subduction|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="797" PostTypeId="2" ParentId="795" CreationDate="2014-05-06T08:50:57.420" Score="9" Body="&lt;p&gt;There was an article in that year's Scientific American, which I've read in the Polish edition. I don't have that paper now, but I think this was that one: &lt;a href=&quot;http://www.scientificamerican.com/article/the-oldest-rocks-on-earth/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Oldest Rocks on Earth&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The discovery is described in short here: &lt;a href=&quot;http://news.nationalgeographic.com/news/2014/02/140224-oldest-crust-australia-zircon-science/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://news.nationalgeographic.com/news/2014/02/140224-oldest-crust-australia-zircon-science/&lt;/a&gt;. It's about Zircon crystals, that are to be 4.4 billion years old. However, as the article states, the found is not (yet?) widely researched. But it's accepted, there are rocks that are 3.8 billion years old.&lt;/p&gt;&#xA;&lt;p&gt;The problem is, only a special kind of crystals could survive the conditions on the young Earth, and zircons are one of them. They preserve only some part of the information about the geological history of the Earth. So it's not like that, that nothing has survived the first billion years, it's only a special minerals and rock did. It's not enough to answer many questions that are of top importance, like the origins of the life (but probably no geological sources would ever do, because of the fragility of the speculated pre-cellular life forms). However, we do get a lot of valuable information that will allow us to learn many facts about the Earth's history we didn't know before.&lt;/p&gt;&#xA;" OwnerUserId="77" LastEditorUserId="18088" LastEditDate="2024-02-14T18:38:53.427" LastActivityDate="2024-02-14T18:38:53.427" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="798" PostTypeId="1" AcceptedAnswerId="833" CreationDate="2014-05-06T09:08:23.890" Score="10" ViewCount="2553" Body="&lt;p&gt;How can one detect (preferably artesian) aquifers nowadays that a lot of sensors are available? Should I use ground-penetrating radars, neutron detectors, or any other advanced devices? Can seismic imaging be used to characterize the extent of the aquifers?&lt;/p&gt;&#xA;" OwnerUserId="269" LastActivityDate="2017-04-28T14:03:04.427" Title="What geophysical instruments should I use to detect water without drilling?" Tags="|geophysics|hydrology|remote-sensing|" AnswerCount="3" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="799" PostTypeId="2" ParentId="691" CreationDate="2014-05-06T09:27:37.997" Score="6" Body="&lt;p&gt;This is not really my specialism, but in the absence of other answers so far, I'll give it a go.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Firstly, to simplify the terms of the question a little bit, flint is a form of chert, so we don't need to distinguish the two terms: we can just talk about chert in general. Also, I'll ignore chert beds formed in siliceous oozes, since you're specifically asking how cherts form in carbonate beds. Nichols (2009) gives a concise explanation, and I don't think I can do better than to quote it:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Diagenetic cherts are formed by the replacement of other material such as calcium carbonate by waters rich in silica flowing through the rock. The source of the silica is mainly biogenic with the opaline silica of&#xA;  diatoms, radiolarian and siliceous sponges being redistributed. Chert formed in this way occurs as nodules within a rock, such as the dark flint nodules that are common within the Cretaceous Chalk, and as nodules and irregular layers within other limestones and mudstones.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;If you want more detail, Maliva and Siever (1989) would probably be a good reference. (Free online reading for all, and download for many institutions, at the &lt;a href=&quot;http://www.jstor.org/stable/30078348&quot;&gt;JSTOR page&lt;/a&gt;.) Here's the abstract:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Mapping of carbonate dissolution in nodular chert-bearing strata indicates that nodular chert formation in a diverse suite of Phanerozoic limestones occurred in bulk pore waters that were at calcite saturation. Opal-CT and quartz supersaturation was achieved in most chert-bearing strata by the intraformational dissolution of amorphous silica skeletal material. Chertification occurred by a combination of force of crystallization-controlled replacement of the host carbonate, whereby non-hydrostatic stresses resulting from opal-CT and quartz crystal growth caused calcite dissolution, and the isomineralic heterogenous nucleation of new opal-CT and quartz crystal at nodule peripheries. The restriction of the solution phase at silica-carbonate contacts to thin films permitted the preservation of ghosts of micron-sized features in the chert. Heterogeneities in sediment organic matter content, porosity, and biogenic silica concentrations promote the nucleation of chert nodules in some formations.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Maliva, R. G., &amp;amp; Siever, R. (1989). Nodular chert formation in carbonate rocks. &lt;em&gt;The Journal of Geology&lt;/em&gt;, 421‒433.&lt;/li&gt;&#xA;&lt;li&gt;Nichols, G. (2009). &lt;em&gt;Sedimentology and stratigraphy&lt;/em&gt;. John Wiley &amp;amp; Sons.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="94" LastActivityDate="2014-05-06T09:27:37.997" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="801" PostTypeId="5" CreationDate="2014-05-06T13:30:46.993" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-05-06T13:30:46.993" LastActivityDate="2014-05-06T13:30:46.993" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="802" PostTypeId="4" CreationDate="2014-05-06T13:30:46.993" Score="0" Body="A tropical cyclone is a rapidly-rotating storm system characterized by a low-pressure center, strong winds, and a spiral arrangement of thunderstorms that produce heavy rain. Depending on its location and strength, a tropical cyclone is referred to by names such as hurricane, typhoon, tropical storm, cyclonic storm, tropical depression, and cyclone." OwnerUserId="140" LastEditorUserId="140" LastEditDate="2014-05-06T14:19:03.517" LastActivityDate="2014-05-06T14:19:03.517" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="803" PostTypeId="2" ParentId="724" CreationDate="2014-05-06T13:51:58.047" Score="0" Body="&lt;p&gt;Likely factor to be the underlying ring of fire underneath the sea, but there are other natural interactions causING the cycles to start and finish. Cold Antarctic  sea moving up the South American coast mixing with tropical warm sea water near the equator is the other major cause and affect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*&quot;El Niño results from interaction between the surface layers of the ocean and the overlying atmosphere in tropical Pacific. It is the internal dynamics of the coupled ocean-atmosphere system that determine the onset and termination of El Niño events. The physical processes are complicated, but they involve unstable air-sea interaction and planetary scale oceanic waves. The system oscillates between warm (El Niño) to neutral (or cold) conditions with a natural periodicity of roughly 3-4 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.pmel.noaa.gov/tao/elnino/faq.html#what&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.pmel.noaa.gov/tao/elnino/faq.html#what&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to another source &quot;&lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/1573563781&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.amazon.com/Oryx-Resource-Guide-Nino-Nina/dp/1573563781&lt;/a&gt;&quot;&#xA;External forcing heat from volcanic eruptions (submarine or terrestrial) &lt;strong&gt;could&lt;/strong&gt; have connection with El Niño. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/AhpO0.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image source:&#xA;&lt;a href=&quot;http://www.universetoday.com/31139/ring-of-fire-volcanoes/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.universetoday.com/31139/ring-of-fire-volcanoes/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="398" LastEditorUserId="398" LastEditDate="2014-05-06T14:27:42.227" LastActivityDate="2014-05-06T14:27:42.227" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="806" PostTypeId="1" AcceptedAnswerId="807" CreationDate="2014-05-06T16:18:51.560" Score="7" ViewCount="3796" Body="&lt;p&gt;Looking for a historic record of the average temperature on Earth going back millions of years, and this &lt;a href=&quot;http://www.scotese.com/climate.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;2002 graphic the from the PALEOMAP Project&lt;/a&gt; is currently the best I am able to find. Is it accurate, and if so, why? If it is not accurate, is there a graph that is?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/SQZfW.png&quot; alt=&quot;average temperature on Earth going back millions; temperature range is between 25 to 10 C&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="64" LastEditDate="2014-05-07T01:45:30.413" LastActivityDate="2014-05-07T01:45:30.413" Title="Is this graph showing the average temperature on Earth going back millions of years accurate?" Tags="|temperature|paleoclimatology|" AnswerCount="1" CommentCount="11" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="807" PostTypeId="2" ParentId="806" CreationDate="2014-05-06T17:08:45.777" Score="12" Body="&lt;p&gt;In a word, no.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The graph is based on work by Chris Scotese. The climate science site RealClimate.org has this to say about it:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Scotese is an expert in reconstructions of continental positions through time and in creating his ‘temperature reconstruction’ he is basically following an old-fashioned idea (best exemplified by Frakes et al’s 1992 textbook) that the planet has two long-term stable equilibria (‘warm’ or ‘cool’) which it has oscillated between over geologic history. This kind of heuristic reconstruction comes from the qualitative geological record which gives indications of glaciations and hothouses, but is not really adequate for quantitative reconstructions of global mean temperatures. Over the last few decades, much better geochemical proxy compilations with better dating have appeared (for instance, Royer et al (2004)) and the idea that there are only two long-term climate states has long fallen by the wayside.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Some better examples of long term climate change graphics do exist. This one from Veizer et al (2000) for instance (as rendered by Robert Rohde):&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/HLXgl.png&quot; alt=&quot;Phanerozoic Climate Change&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a more detailed discussion of graphical reconstructions, see &lt;a href=&quot;http://www.realclimate.org/index.php/archives/2014/03/can-we-make-better-graphs-of-global-temperature-history/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this RealClimate entry&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="30" LastEditorUserId="30" LastEditDate="2014-05-06T22:32:02.860" LastActivityDate="2014-05-06T22:32:02.860" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="808" PostTypeId="1" AcceptedAnswerId="812" CreationDate="2014-05-06T17:19:02.207" Score="8" ViewCount="12300" Body="&lt;p&gt;Whenever weather warnings come up, I have heard of both a flood watch/warning and a flash flood watch/warning. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is the difference between a &quot;flood&quot; and a &quot;flash flood&quot;?&lt;/strong&gt; Are there any specific meteorological/weather forecasting patterns that distinguish one from the other? &lt;/p&gt;&#xA;" OwnerDisplayName="user402" LastActivityDate="2014-05-06T17:36:02.223" Title="What is the difference between a &quot;flood&quot; and a &quot;flash flood&quot;?" Tags="|meteorology|weather|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="809" PostTypeId="1" AcceptedAnswerId="814" CreationDate="2014-05-06T17:25:46.270" Score="11" ViewCount="719" Body="&lt;p&gt;In 2007, the US started using an Enhanced Fujita Scale in place of the Fujita Scale. From a &quot;civilian's&quot; perspective, the Fujita Scale seemed to measure wind whereas the Enhanced Fujita Scale measures damage. This would suggest that tornadoes based on the EF scale is retroactively labeled rather than labeled while the tornado is taking place. Also, going from saying &quot;F5&quot; to &quot;EF5&quot; is a change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is the motivation of using the Enhanced Fujita Scale in place of the Fujita Scale?&lt;/strong&gt; What are the main differences of the two scales that allowed the Enhanced Fujita Scale to be used today in the US?&lt;/p&gt;&#xA;" OwnerDisplayName="user402" LastEditorUserId="64" LastEditDate="2014-05-06T18:33:17.293" LastActivityDate="2014-05-06T18:33:17.293" Title="What is the motivation of using the Enhanced Fujita Scale in place of the Fujita Scale?" Tags="|meteorology|weather|tornado|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="810" PostTypeId="1" AcceptedAnswerId="820" CreationDate="2014-05-06T17:32:11.277" Score="17" ViewCount="4350" Body="&lt;p&gt;Since reliable modern records of climate only began in the 1880s, proxies provide a means for scientists to determine climatic patterns before record-keeping began, though it appears that the the distribution of &lt;a href=&quot;http://en.wikipedia.org/wiki/Proxy_%28climate%29&quot;&gt;proxy records&lt;/a&gt; for global average temperatures, just like the instrumental record, is &lt;a href=&quot;http://en.wikipedia.org/wiki/File:2000_Year_Temperature_Comparison.png&quot;&gt;strongly non-uniform&lt;/a&gt;, with more records in the northern hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How accurate are climate proxies in giving us a clear picture of global average temperatures throughout Earth history?&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="140" LastEditDate="2014-05-06T19:47:50.077" LastActivityDate="2021-08-11T10:47:54.100" Title="How accurate are climate proxies in giving us a clear picture of global average temperatures throughout Earth history?" Tags="|meteorology|climate|temperature|paleoclimatology|" AnswerCount="2" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="811" PostTypeId="1" CreationDate="2014-05-06T17:33:27.370" Score="14" ViewCount="4198" Body="&lt;p&gt;Historically, the Atlantic Hurricane Season has shifted, as close as June 15 to October 31, but since 1965, it has been between June 1 and November 30&lt;sub&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Atlantic_hurricane_season#Concept&quot;&gt;(1)&lt;/a&gt;&lt;/sub&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Why is the Atlantic Hurricane Season defined as being between June 1 and November 30?&lt;/strong&gt; I know most hurricanes happen within this timeframe, but it seems, to the civilian eye, to be the strongest during August and September.&lt;/p&gt;&#xA;" OwnerDisplayName="user402" LastEditorDisplayName="user402" LastEditDate="2014-05-06T18:49:29.940" LastActivityDate="2014-05-06T22:48:00.073" Title="Why is the Atlantic Hurricane Season defined as being between June 1 and November 30?" Tags="|meteorology|weather|tropical-cyclone|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="812" PostTypeId="2" ParentId="808" CreationDate="2014-05-06T17:36:02.223" Score="8" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Flood:&lt;/strong&gt; An overflow of water onto normally dry land. The inundation of a normally dry area caused by rising water in an existing waterway,&#xA;  such as a river, stream, or drainage ditch. Ponding of water at or&#xA;  near the point where the rain fell. Flooding is a longer term event&#xA;  than flash flooding: it may last days or weeks.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;strong&gt;Flash flood:&lt;/strong&gt; A flood caused by heavy or excessive rainfall in a short period of time, generally less than 6 hours. Flash floods are&#xA;  usually characterized by raging torrents after heavy rains that rip&#xA;  through river beds, urban streets, or mountain canyons sweeping&#xA;  everything before them. They can occur within minutes or a few hours&#xA;  of excessive rainfall. They can also occur even if no rain has fallen,&#xA;  for instance after a levee or dam has failed, or after a sudden&#xA;  release of water by a debris or ice jam. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;em&gt;Source: &lt;a href=&quot;http://www.srh.noaa.gov/mrx/hydro/flooddef.php&quot;&gt;National Weather Service Weather Forecast Office&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="284" LastActivityDate="2014-05-06T17:36:02.223" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="813" PostTypeId="2" ParentId="811" CreationDate="2014-05-06T18:20:29.357" Score="7" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Hurricanes form over tropical waters (between 8 and 20 degrees&#xA;  latitude) in areas of high humidity, light winds, and warm sea surface&#xA;  temperatures [typically 26.5 degrees Celsius (80 Fahrenheit) or&#xA;  greater]. These conditions usually prevail in the summer and early&#xA;  fall months of the tropical North Atlantic and North Pacific Oceans,&#xA;  and for this reason, hurricane “season” in the northern hemisphere&#xA;  runs from June through November.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;source: &lt;a href=&quot;http://earthobservatory.nasa.gov/Features/Hurricanes/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/sFcZZ.jpg&quot; alt=&quot;Global map of hurricane formation timing based on warm sea surface temperatures&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;CAPTION:&lt;/strong&gt; Global map of hurricane formation timing based on warm sea surface temperatures.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/I1cT2.jpg&quot; alt=&quot;Mosaic of all tropical storms that formed in the world between 1985 and 2005. As can be seen the majority occur in the Pacific Basin. &quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;CAPTION:&lt;/strong&gt; Mosaic of all tropical storms that formed in the world between 1985 and 2005. As can be seen the majority occur in the Pacific Basin.&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the stronger storms, the logical answer is that the frequency of storms during a given period is directly related to the likelihood that the storm will have more energy. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/nXIYM.jpg&quot; alt=&quot;Chart illustrating the worldwide frequency of tropical storms (blue area) and storms of hurricane/typhoon intensity (pink area) by month of occurrence.&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;CAPTION:&lt;/strong&gt; Chart illustrating the worldwide frequency of tropical storms (blue area) and storms of hurricane/typhoon intensity (pink area) by month of occurrence.&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/vrewH.jpg&quot; alt=&quot;Frequency graph of Atlantic hurricanes and tropical storms by month with peak in September and 97% between of all activity taking place between June 1 to November 30. &quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;CAPTION:&lt;/strong&gt; Frequency graph of Atlantic hurricanes and tropical storms by month with peak in September and 97% between of all activity taking place between June 1 to November 30.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;h2&gt;Is the hurricane season getting longer per year?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Yes, it is getting longer according to &lt;a href=&quot;http://www.ssec.wisc.edu/~kossin/articles/2008GL036012.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;research based&lt;/a&gt; on the first and last hurricanes of the year - (which I found as a result of &lt;a href=&quot;https://earthscience.stackexchange.com/a/818/284&quot;&gt;this answer&lt;/a&gt;) - though my analysis that this research just reflects that &lt;a href=&quot;https://en.wikipedia.org/wiki/Atlantic_hurricane_season#Concept&quot; rel=&quot;nofollow noreferrer&quot;&gt;we see more hurricanes now as a result of satellite imagery&lt;/a&gt;, not as a result of there being more storms.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/cnga3.jpg&quot; alt=&quot;Time series of the first and last tropical storm formation events each year in the Atlantic&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;CAPTION:&lt;/strong&gt; Time series of the first and last tropical storm formation events each year in the Atlantic; red-lines (non-aircraft, non-satellite records); blue-lines (aircraft-based records included); green (saterllite based).&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-05-06T22:48:00.073" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="814" PostTypeId="2" ParentId="809" CreationDate="2014-05-06T18:24:16.960" Score="9" Body="&lt;p&gt;Both the Fujita (F) and Enhanced Fujita (EF) scales measure damage and then use damage as a proxy for wind speed.  Wind speed at the low levels is not directly measured unless the tornado is either very close to a doppler radar site or there happens to be a mobile radar sampling it.  This provides very few tornadoes with directly sampled wind speed and is the exception rather than the rule.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where the F and EF scales differ primarly is that in the EF scale construction methods may be considered, not just the damage observed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Damage is used as a proxy for windspeed by examining damage, construction techniques and methods (EF scale only), materials, and other factors and then determining what threshold wind speed could cause that damage.  This means that identical damage can result in different windspeed estimates.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, a house that is completely destroyed and leaves behind a clean concrete slab is generally considered EF-5 damage, but some houses with poor construction have been found to not be physically tied to the foundation.  A particular case in northern GA, USA had tornado winds blow down a garage door and then lift the house directly off the slab and take it away.  This also leaves a clean concrete slab, but the construction methods will cause a lower wind estimate and a weaker tornado determination because less wind was required to cause the damage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only other difference between the F and EF scales are that some of the wind speed estimates have been lowered in the EF scale and more descriptive damage indicators are used for wind speed estimates to help standardize those estimates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In summary, the EF scale differs from the F scale:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;EF scale can consider construction methods&lt;/li&gt;&#xA;&lt;li&gt;EF scale has more descriptive damage indicators used to estimate wind speed&lt;/li&gt;&#xA;&lt;li&gt;EF scale has reduced wind speeds in each category to better align with engineering estimates of damage&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-05-06T18:24:16.960" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="815" PostTypeId="5" CreationDate="2014-05-06T18:30:50.120" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-05-06T18:30:50.120" LastActivityDate="2014-05-06T18:30:50.120" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="816" PostTypeId="4" CreationDate="2014-05-06T18:30:50.120" Score="0" Body="Questions about the application of weather data in meteorology/forecasting. " OwnerDisplayName="user402" LastEditorDisplayName="user402" LastEditDate="2014-05-06T18:45:18.340" LastActivityDate="2014-05-06T18:45:18.340" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="817" PostTypeId="1" AcceptedAnswerId="819" CreationDate="2014-05-06T19:03:39.590" Score="15" ViewCount="603" Body="&lt;p&gt;Blizzards are most commonly associated with a large amount of snowfall and low visibility. However, snow squalls can induce low visibility whereas a 12&quot; snowfall doesn't have to induce low visibility.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What constitutes a blizzard in meterological terms?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user402" LastActivityDate="2014-05-06T19:09:48.657" Title="What constitutes a blizzard in meterological terms?" Tags="|meteorology|weather|snow|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="818" PostTypeId="2" ParentId="811" CreationDate="2014-05-06T19:08:24.837" Score="8" Body="&lt;p&gt;The hurricane season is set by the &lt;a href=&quot;http://www.nhc.noaa.gov/&quot;&gt;National Hurricane Center&lt;/a&gt;.  They use statistics to determine the dates.  Specifically:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Atlantic hurricane season is officially from 1 June to 30 November. There is nothing magical in these dates, and hurricanes have occurred outside of these six months, but these dates were selected to encompass over 97% of tropical activity.  June 1st has been the traditional start of the Atlantic hurricane season for decades. However, the end date has been slowly shifted outward, from October 31st to November 15th until its current date of November 30th&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/G1.html&quot;&gt;NHC&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As for why the dates are spreading out (from October to November), it appears that the dates of the hurricanes themselves are spreading out. (per &lt;a href=&quot;http://www.ssec.wisc.edu/~kossin/articles/2008GL036012.pdf&quot;&gt;James P. Kossin&lt;/a&gt; [1])&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, the dates are getting wider because the hurricanes are spreading out throughout the season.  So, the NHC widens the dates throughout the years to correctly cover the majority of the hurricanes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;&#xA;[1] James P. Kossin - Is the North Atlantic hurricane season getting longer? &lt;br&gt;GEOPHYSICAL RESEARCH LETTERS, VOL. 35, L23705, doi:10.1029/2008GL036012, 2008&#xA;James P. Kossin&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="330" LastActivityDate="2014-05-06T19:08:24.837" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="819" PostTypeId="2" ParentId="817" CreationDate="2014-05-06T19:09:48.657" Score="14" Body="&lt;p&gt;A blizzard is defined as &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;sustained wind or frequent gusts &gt;= 16 m per second (30 kt or 35 mi per hour)&lt;/li&gt;&#xA;&lt;li&gt;falling / blowing snow, frequently reducing visibility to less than 400 m (0.25 mi)&lt;/li&gt;&#xA;&lt;li&gt;3 hours or longer in duration&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;A storm meeting these qualifications is a blizzard.  Note that snowfall is not necessary, a sustained 35 kt wind blowing snow for 3 hours with low visibility is a blizzard.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A severe weather condition characterized by high winds and reduced visibilities due to falling or blowing snow. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The U.S. National Weather Service specifies sustained wind or frequent gusts of 16 m per second (30 kt or 35 mi per hour) or greater, accompanied by falling and/or blowing snow, frequently reducing visibility to less than 400 m (0.25 mi) for 3 hours or longer. Earlier definitions also included a condition of low temperatures, on the order of -7°C (20°F) or lower, or -12°C (10°F) or lower (severe blizzard). The name originated in the United States but it is also used in other countries. In the Antarctic the name is given to violent autumnal winds off the ice cap. In southeastern France, the cold north wind with snow is termed blizzard (see also boulbie). &#xA;  Similar storms in Russian Asia are the buran and purga. In popular usage in the United States and in England, the term is often used for any heavy snowstorm accompanied by strong winds.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Blizzard&quot;&gt;AMS Glossary: Blizzard&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-05-06T19:09:48.657" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="820" PostTypeId="2" ParentId="810" CreationDate="2014-05-06T21:39:55.410" Score="15" Body="&lt;p&gt;Overall, any individual proxy is not a reliable indicator.  It's the combination of multiple proxies that provides a clearer picture. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, tree ring growth has been correlated with temperatures.  However, it's not without it's anomalies:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...from the middle of the 20th century tree ring growth was less than might have been expected from the temperature record... ([source]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.climatedata.info/Proxy/Proxy/treerings_introduction.html&quot;&gt;http://www.climatedata.info/Proxy/Proxy/treerings_introduction.html&lt;/a&gt;)) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we were to only look at tree-rings, we could not possibly trust on them as a reliable source, since they have known problems.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can also use coral as a indicator of past climate.  However, it's also somewhat questionable:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;However, long (multi-centure) records are rare, and the possible influence of non-climatic influences has not yet been confidently established.&#xA;  &lt;a href=&quot;http://www.meteo.psu.edu/holocene/public_html/shared/articles/MannPersp2002.pdf&quot;&gt;source&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Ice-cores are not immune to skepticism:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;An indisputable interpretation of ice-core oxygen isotopes in terms of&#xA;  atmospheric temperature variability, moreover, remains elusive, and&#xA;  precise annual dating can be difficult.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, if we can combine these three indicates along with other indicators (pollen, earth bores, etc), we can increase the reliability of our understanding.  For example, if most indicators show a cold year, we can more reliability say it was a cold year.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Combining these proxies together helps us to gain a clearer picture of the past environment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Overall Reliability&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, with that said, the amount of uncertainty with the multi-proxy method is not small.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the Workshop on Mathematics in the Geosciences, Blake McShane presented a new algorithm for estimating paleoclimate.  This algorithm provided a more reliable estimate by &lt;em&gt;increasing the uncertainty&lt;/em&gt; of the predictions.  That's an important point that I will restate:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Through his talk, he showed that his method was &lt;em&gt;more reliable&lt;/em&gt; because it was &lt;em&gt;less certain&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even that wide uncertainty level, he questioned:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Indeed, this should make us &lt;em&gt;increase&lt;/em&gt; our level of uncertainty (indeed perhaps &#xA;  our wide intervals are in fact optimistically too narrow)!&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;a href=&quot;http://www.earth.northwestern.edu/people/seth/Mathgeo/mcshane.pdf&quot;&gt;source&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In the end, we can look at proxies for guidelines and trends, but they cannot be used for reliable readings.&lt;/p&gt;&#xA;" OwnerUserId="330" LastEditorUserId="284" LastEditDate="2014-05-07T07:15:57.290" LastActivityDate="2014-05-07T07:15:57.290" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="821" PostTypeId="1" AcceptedAnswerId="822" CreationDate="2014-05-06T22:09:40.637" Score="6" ViewCount="90" Body="&lt;p&gt;Seems like the &lt;a href=&quot;http://www.wired.com/2014/04/soundscape-recorder/&quot;&gt;Earth Day related crowd sourcing project&lt;/a&gt; to create the first &lt;a href=&quot;https://globalsoundscapes.org/&quot;&gt;global soundscape&lt;/a&gt; by encouraging smartphone owners around the world to download and use an app developed to record the sounds around them is interesting, though it's unclear what scientific value it would have. &lt;strong&gt;Is there any scientific value to understanding soundscapes on a global basis?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastActivityDate="2014-05-07T00:25:19.983" Title="What, if any, scientific value do global soundscapes have?" Tags="|atmosphere|measurements|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="822" PostTypeId="2" ParentId="821" CreationDate="2014-05-07T00:25:19.983" Score="0" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Remote sensing using &lt;a href=&quot;http://en.wikipedia.org/wiki/Remote_sensing#Acoustic_and_near-acoustic&quot; rel=&quot;nofollow&quot;&gt;passive sonar and seismograms&lt;/a&gt;, which are&#xA;  acoustic or near-acoustic signals, works on the principle of the&#xA;  inverse problem. While the object or phenomenon of interest (the&#xA;  state) may not be directly measured, there exists some other variable&#xA;  that can be detected and measured (the observation), which may be&#xA;  related to the object of interest through the use of a data-derived&#xA;  computer model.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Soundscape_ecology&quot; rel=&quot;nofollow&quot;&gt;Soundscape ecology&lt;/a&gt; is the study of sound within a landscape and&#xA;  its effect on organisms. Sounds may be generated by organisms&#xA;  (biophony), by the physical environment (geophony), or by humans&#xA;  (anthrophony). Soundscape ecologists seek to understand how these&#xA;  different sound sources interact across spatial scales and through&#xA;  time. Variation in soundscapes may have wide-ranging ecological&#xA;  effects as organisms often obtain information from environmental&#xA;  sounds. Soundscape ecologists use recording devices, audio tools, and&#xA;  elements of traditional ecological analyses to study soundscape&#xA;  structure. Increasingly, anthrophony, sometimes referred to in older,&#xA;  more archaic terminology as anthropogenic noise dominates soundscapes,&#xA;  and this type of noise pollution or disturbance has a negative impact&#xA;  on a wide range of organisms. The preservation of natural soundscapes&#xA;  is now a recognized conservation goal.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: Wikipedia links referenced above.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="284" LastActivityDate="2014-05-07T00:25:19.983" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="823" PostTypeId="2" ParentId="332" CreationDate="2014-05-07T03:03:38.507" Score="7" Body="&lt;p&gt;According to &lt;a href=&quot;https://en.wikipedia.org/wiki/Soil_horizon#R_horizon&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt; and &lt;a href=&quot;http://www.nature.com/scitable/knowledge/library/what-are-soils-67647639&quot; rel=&quot;noreferrer&quot;&gt;Nature.com&lt;/a&gt;, &lt;strong&gt;&quot;R Horizon&quot; is the official letter for bedrock.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/c2xMO.jpg&quot; alt=&quot;Example soil with designations that communicate the soil formation processes occurring in each horizon.&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;CAPTION:&lt;/strong&gt; Example soil with designations that communicate the soil formation processes occurring in each horizon.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastActivityDate="2014-05-07T03:03:38.507" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="824" PostTypeId="2" ParentId="28" CreationDate="2014-05-07T03:19:01.407" Score="4" Body="&lt;h2&gt;Clouds on Venus&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;After a quick search, it appears the &lt;a href=&quot;http://www.universetoday.com/36871/clouds-on-venus/&quot; rel=&quot;nofollow&quot;&gt;clouds found on Venus&lt;/a&gt; are different than Earth's:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Venus is covered by a thick layer of clouds. These clouds are made&#xA;  mostly of sulfuric acid and are very fast moving, going up to 220&#xA;  miles per hour (350 km per hour). The clouds rotate 60 times faster&#xA;  than the planet rotates. The clouds circle Venus in four Earth days;&#xA;  the planet rotates around its axis in 243 Earth days. These&#xA;  quickly-moving clouds distribute the heat around the planet, making&#xA;  the night side hot also. V-shaped cloud patterns are visible in the&#xA;  middle latitudes when the clouds are examined in ultraviolet light.&#xA;  The clouds rain sulphuric acid (extremely acid rain), but this&#xA;  corrosive precipitation does not reach the surface. The high heat&#xA;  beneath the clouds (up to 220°C) evaporates the rain drops about 10&#xA;  miles (30 km) above Venus. &lt;a href=&quot;http://www.enchantedlearning.com/subjects/astronomy/planets/venus/venusatmosphere.shtml&quot; rel=&quot;nofollow&quot;&gt;SOURCE&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;h2&gt;Clouds on Titan&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;According to this release by NASA, &lt;a href=&quot;http://www.nasa.gov/mission_pages/cassini/whycassini/titan-clouds.html&quot; rel=&quot;nofollow&quot;&gt;Titan has &quot;cirrus-like&quot; clouds&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Now, thin, wispy clouds of ice particles, similar to Earth's cirrus&#xA;  clouds, are being reported by Carrie Anderson and Robert Samuelson at&#xA;  NASA's Goddard Space Flight Center in Greenbelt, Md. The findings,&#xA;  published February 1 in Icarus, were made using the Composite Infrared&#xA;  Spectrometer (CIRS) on NASA's Cassini spacecraft.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="284" LastActivityDate="2014-05-07T03:19:01.407" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="825" PostTypeId="1" AcceptedAnswerId="828" CreationDate="2014-05-07T03:36:15.547" Score="38" ViewCount="51510" Body="&lt;p&gt;I do know that the atmosphere protects life on Earth by absorbing ultraviolet solar radiation, warming the surface through heat retention (greenhouse effect),and reducing temperature extremes between day and night (the diurnal temperature variation). I wonder what temperature would earth reach if there was no atmosphere?.&lt;/p&gt;&#xA;" OwnerUserId="412" LastEditorUserId="87" LastEditDate="2014-11-19T15:09:03.330" LastActivityDate="2022-09-18T22:46:26.130" Title="What would be the temperature of earth if there was no atmosphere?" Tags="|atmosphere|temperature|" AnswerCount="3" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="828" PostTypeId="2" ParentId="825" CreationDate="2014-05-07T06:27:49.207" Score="32" Body="&lt;p&gt;According to &lt;a href=&quot;http://en.wikipedia.org/wiki/Black-body_radiation#Temperature_of_Earth&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt; an approximate average surface temperature for a bare earth is 274.5 K. This scenario is quite reasonable in my opinion as stripping the atmosphere without changing much else would (on a geological timescale) rather quickly result in a bare earth without ice caps or vegetation, causing circumstances quite close to those on the moon. (I assume the Earth's magnetic field protecting both the atmosphere and life below it has disappeared as well)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is estimated by comparing the black body radiation of the Earth and Moon, which is then corrected for albedo (fraction of incoming radiation that is reflected) and emissivity (ability of a material to emit radiation), which are properties of a material. Since the Earth and moon are both at the same distance to the sun and made up from the same material on average, measurements of the albedo and emissivity of the moon can than be used as estimations of these properties for the Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The black body radiation of the sun is calculated with the Stefan-Boltzmann law:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$P_{\text{S,emit}} = 4\pi R_S^2 \sigma T_S^4$$   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$P_{\text{S,emit}}$ is the emitted energy by the sun, $R_S$ is the radius of the sun, and $T_S$ is the temperature of the sun. The fraction of this energy recieved by the Earth is then proportional to the circular surface area facing the sun and the energy density at the distance $D$ between the Earth and the sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$P_{\text{SE}} = P_{\text{S,emit}}\left(\frac{\pi R_E^2}{4\pi D^2}\right)$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$R_E$ is the Earth's radius. Using albedo $\alpha$ the absorbed energy can be calculated:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$P_{\text{E,abs}} = (1-\alpha)P_{\text{SE}}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Applying the Stefan-Boltzman law to the Earth, corrected for the emissivity $\overline{\epsilon}$, the emitted energy is then:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$P_{\text{E,emit}} = \overline{\epsilon} 4\pi R_E^2 \sigma T_E^4$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming energy equilibrium $P_{\text{E,abs}} = P_{\text{E,emit}}$ we can now calculate $T_E$:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\begin{aligned}&#xA;\frac{(1-\alpha)4\pi R_S^2 \sigma T_S^4\pi R_E^2}{4\pi D^2} &amp;amp; = \overline{\epsilon}4\pi R_E^2 \sigma T_E^4 \\ &#xA;T_E^4 &amp;amp; = \frac{(1-\alpha)4\pi R_S^2 \sigma T_S^4\pi R_E^2}{\overline{\epsilon}4\pi D^2 4\pi R_E^2 \sigma} \\  &#xA;T_E^4 &amp;amp; = \frac{(1-\alpha) R_S^2 T_S^4}{ 4\overline{\epsilon}D^2  } \\ &#xA;T_E &amp;amp; = \left( \frac{(1-\alpha) R_S^2 T_S^4}{4 \overline{\epsilon}D^2 }\right)^{\frac{1}{4}} \\  &#xA;T_E &amp;amp; = T_S \left( \frac{(1-\alpha) R_S^2}{4 \overline{\epsilon} D^2 }\right)^{\frac{1}{4}} \\  &#xA;T_E &amp;amp; = T_S \sqrt{ \frac{ R_S \sqrt{\frac{1-\alpha}{\overline{\epsilon}}} }{2 D } }&#xA;\end{aligned}$$  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally we only need to insert the correct values:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$R_S = 6.96\times 10^8$ m&lt;/li&gt;&#xA;&lt;li&gt;$T_S = 5778$ K&lt;/li&gt;&#xA;&lt;li&gt;$D = 1.496\times 10^{11}$ m&lt;/li&gt;&#xA;&lt;li&gt;$\alpha = 0.1054$ (assuming value of the moon)&lt;/li&gt;&#xA;&lt;li&gt;$\overline{\epsilon} = 0.95$ (assuming value of the moon)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;This gives us a temperature of 274.5 K.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that there are many factors that can cause local and temporal variations. For example, incoming radiation varies with latitude and season, and if the removal of the atmosphere would be caused by a dying sun that grows to engulf the earth temperatures would be much higher than this. All in all, to account for all those factors a very large model must be made that can analyse the influence of each factor, including the decrease in temperature of a dying sun etc., but that would be nearly impossible to build if only for the resources it would take to do so.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since one of the most contested factors is the albedo after the atmosphere is removed the following graph shows how the average surface temperature changes with albedo. At an albedo of zero all incoming solar radiation is absorbed, while at 1 all radiation is reflected. Note that the temperature of 0K is an effect of the assumed equilibrium between incoming and emitted radiation, which will not hold at that point. As said above, the albedo for a bare earth will be approximately 0.1, while current values on average range from 0.3-0.4, largely contributed to by clouds. An average for the albedo of the Earth in its current vegetated state, but without clouds I haven't been able to find.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As stated by @ardie-j in his answer, another possible fate of the Earth could be that it gets covered in ice, as another Snowball Earth Event. In that case the albedo would rise to levels ranging from 0.4-0.9, resulting in a drastically cooler Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/aaShA.png&quot; alt=&quot;Black body temperature of earth with albedo&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="79" LastEditorUserId="79" LastEditDate="2016-09-13T20:12:59.743" LastActivityDate="2016-09-13T20:12:59.743" CommentCount="15" ContentLicense="CC BY-SA 3.0" />
  <row Id="829" PostTypeId="2" ParentId="368" CreationDate="2014-05-07T07:05:16.797" Score="10" Body="&lt;p&gt;Though I agree with @kaberett that there is indeed more and more evidences that the Deccan volcanism was the main trigger of the K/Pg crisis, i wanted to add that there is a more nuanced hypothesis (that I heard about last week during a &lt;a href=&quot;http://meetingorganizer.copernicus.org/EGU2014/EGU2014-3042.pdf&quot;&gt;talk at EGU&lt;/a&gt;) according to which the Chicxulub impact resulting seismic response may be the trigger of one of the main stage of the Deccan eruptions (Stage II if i remember correctly). This idea is based on the seismic modeling of meteorite impact by Meschede et al. 2011.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Sources:&lt;br&gt;&#xA;Meschede, M. A., Myhrvold, C. L. and Tromp, J. (2011), &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1111/j.1365-246X.2011.05170.x/full&quot;&gt;Antipodal focusing of seismic waves due to large meteorite impacts on Earth.&lt;/a&gt; Geophysical Journal International, 187: 529–537.&lt;br&gt;&#xA;Richards, M. et al. (2014), &lt;a href=&quot;http://meetingorganizer.copernicus.org/EGU2014/EGU2014-3042.pdf&quot;&gt;Possible Triggering of the Largest Deccan Eruptions by the Chicxulub Impact.&lt;/a&gt; Geophysical Research Abstracts, 16: EGU2014-3042.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-05-07T12:33:12.477" LastActivityDate="2014-05-07T12:33:12.477" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="830" PostTypeId="2" ParentId="798" CreationDate="2014-05-07T12:24:33.293" Score="6" Body="&lt;p&gt;&lt;a href=&quot;http://www.teamhydrosource.com/about_us/index.asp&quot;&gt;Hydrosource Associates&lt;/a&gt; (no personal relation) claims to use the following:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;HSA’s use of geophysical instruments and methods includes seismic, electrical resistivity, ground penetrating radar, electromagnetic, magnetic, gravimetric, self-potential, and magnetotelluric.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Since you're looking for a list, you could investigate each of those technologies above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the one instrument not mentioned above and the most high recommended method is simply &lt;a href=&quot;http://www.kgs.ku.edu/Publications/PIC/pic23.html&quot;&gt;using geological maps&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="330" LastActivityDate="2014-05-07T12:24:33.293" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="831" PostTypeId="2" ParentId="798" CreationDate="2014-05-07T14:01:03.623" Score="4" Body="&lt;p&gt;I'm not an ideal person to answer this, but that's never stopped me before, so here goes! :)  I've helped several hydrologists with the geophysical side of things at various points, but I'm not in any form or fashion a hydrologist myself.  My father did the government permitting for residential water wells and septic systems where I grew up, though, so I've seen a bit of things from both the academic side and the practical side.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For locating the average residential water supply well, gephysical methods are basically never used.  They're just too expensive compared to drilling the well.  &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;However, for making detailed hydrological models, geophysical methods (particularly ground penetrating radar (GPR)) get used quite a bit.  In fact, there's a whole field called &quot;hydrogeophysics&quot; that deals with imaging in near-subsurface environments.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These methods don't get applied for locating a single well. They get applied to build detailed 3D models to constrain things like contaminant transport.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you need to know how groundwater is flowing in 3D, then you need a more detailed image of the subsurface than you do to locate a single water well.  GPR is the most commonly used method, but I've seen almost every sort of geophysical data used in some cases (basically where it's already been collected and is freely available).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically, the bigger the budget, the more fancy tools can get thrown at the problem. :)  &lt;/p&gt;&#xA;" OwnerUserId="12" LastActivityDate="2014-05-07T14:01:03.623" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="833" PostTypeId="2" ParentId="798" CreationDate="2014-05-07T14:21:03.197" Score="6" Body="&lt;p&gt;From what @Richard and @JoeKington said in their answers,&#xA;it seems that the usual way of finding water is through a&#xA;&lt;a href=&quot;http://www.britannica.com/EBchecked/topic/278885/hydrological-map&quot;&gt;hydrological map&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, for the sake of completeness, I'll include here a bit about&#xA;what geophysical methods &lt;strong&gt;could&lt;/strong&gt; be used to find water.&#xA;I'll not comment on the practical issue of cost-benefit as that was nicely explained by @JoeKington in his answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said,&#xA;any geophysical method is only able to detect a &lt;strong&gt;contrast&lt;/strong&gt; of a physical&#xA;property.&#xA;For example, seismic methods are sensitive to variations in seismic wave&#xA;velocity, electric and electromagnetic methods are sensitive to&#xA;resistivity/conductivity, gravimetry is sensitive to density variations, etc.&#xA;So for any geophysical method to detect water, there has to be a contrast in&#xA;the physical property between the water level and the surrounding rocks/soil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Knowing this we can already rule out&#xA;&lt;a href=&quot;http://en.wikipedia.org/wiki/Gravimetry&quot;&gt;gravimetry&lt;/a&gt; and&#xA;&lt;a href=&quot;http://en.wikipedia.org/wiki/Magnetic_survey_%28archaeology%29&quot;&gt;magnetometry&lt;/a&gt;&#xA;because there&#xA;is no significant density/magnetization contrast when we reach the water level.&#xA;These methods can give you an idea of the regional geologic setting, and that&#xA;can help you find water. But detecting water directly? Probably not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The presence of water does have an impact on the electrical conductivity but&#xA;that is usually not very large unless the water is salty, which I'm guessing&#xA;you wouldn't want to drink.&#xA;Methods like&#xA;&lt;a href=&quot;http://en.wikipedia.org/wiki/Ground-penetrating_radar&quot;&gt;GPR&lt;/a&gt;&#xA;and&#xA;&lt;a href=&quot;http://www.epa.gov/nerlesd1/cmb/GeophysicsWebsite/pages/reference/methods/Surface_Geophysical_Methods/Electrical_Methods/&quot;&gt;electrical resistivity&#xA;methods&lt;/a&gt;&#xA;could map the depth of the water layer, but this effect might be masked depending on the soil type (clay might have very low resistivity and that makes &quot;seeing&quot; what is beneath very difficult).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seismic wave velocity is usually affected by the presence of water in the&#xA;soil.&#xA;If all you want is the depth of the water level, then&#xA;shallow &lt;a href=&quot;http://en.wikipedia.org/wiki/Seismic_refraction&quot;&gt;seismic refraction&lt;/a&gt; might be a good method for that.&#xA;Acquisition is relatively cheap and the data are easy process (usually just simple trigonometry).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of these methods will not tell you for sure if the water is there or if it&#xA;is drinkable.&#xA;However, they can give a bit more insight to complement the hydrological information.&lt;/p&gt;&#xA;" OwnerUserId="137" LastActivityDate="2014-05-07T14:21:03.197" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="834" PostTypeId="1" AcceptedAnswerId="17251" CreationDate="2014-05-07T14:29:17.840" Score="13" ViewCount="14895" Body="&lt;p&gt;I am wondering what is the tallest fully underwater seamount in the world ? When I say the tallest, I mean the one that is the nearest of the sea level.&#xA;&lt;em&gt;EDIT : The highest that I found would be at about 50m below the water's surface do you know any other seamount that would be even higher ?&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="418" LastEditorUserId="418" LastEditDate="2014-05-07T19:15:46.807" LastActivityDate="2022-08-02T19:04:26.293" Title="What is the tallest fully underwater seamount in the world?" Tags="|ocean|oceanography|mountains|" AnswerCount="4" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="835" PostTypeId="2" ParentId="834" CreationDate="2014-05-07T14:35:16.270" Score="12" Body="&lt;p&gt;According to the &lt;em&gt;Oxford Dictionary of Earth Sciences&lt;/em&gt;,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;seamount&lt;/strong&gt; Isolated, submarine mountain rising more than 1000m above the ocean floor. The sharp, crested summits of seamounts are usually 1000-2000m below the ocean surface. Seamounts are of volcanic origin.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;To avoid classifying seamounts by arbitrary sea level (dependent on availability of surface water), the key point is then that seamounts are features of volcanic origin that rise over 1000m above oceanic crust.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Hawai'i-Emperor seamount chain is of volcanic origin; all of the islands in this chain are seamounts. Mauna Kea only rises 4207m above sea level - but measured from its base on the oceanic plate it is 10100m high, &lt;em&gt;much&lt;/em&gt; taller than Mt Everest. Mauna Kea is - pretty conclusively - the highest seamount in the world. The &lt;a href=&quot;http://www.whoi.edu/main/topic/seamounts&quot;&gt;Woods Hole Oceanographic Institute agrees&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="105" LastEditorUserId="105" LastEditDate="2014-05-07T15:14:05.050" LastActivityDate="2014-05-07T15:14:05.050" CommentCount="15" ContentLicense="CC BY-SA 3.0" />
  <row Id="836" PostTypeId="2" ParentId="783" CreationDate="2014-05-07T14:56:42.710" Score="12" Body="&lt;p&gt;I am a seismologist, not a volcanologist, but we can use a method called seismic tomography to understand the size of magma chambers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This method is similar to a medical CT scan - the magma mush will have a slower seismic wavespeed than the surrounding 'normal' rock. Therefore, we can use this to determine the size of magma chambers from a tomographic image.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even if a volcano does not appear to be active at the surface, it could still overlie a magmatic anomaly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This approach was recently used to estimate the seismic of the Yellowstone magmatic body. See this paper: &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2014GL059588/abstract&quot;&gt;http://onlinelibrary.wiley.com/doi/10.1002/2014GL059588/abstract&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seismic tomography can theoretically be applied to any region, but we just need to have enough seismic sources nearby (e.g. earthquakes) to be able to do this accurately. &lt;/p&gt;&#xA;" OwnerUserId="419" LastActivityDate="2014-05-07T14:56:42.710" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="837" PostTypeId="2" ParentId="73" CreationDate="2014-05-07T15:04:38.980" Score="11" Body="&lt;p&gt;The East Midlands region of the UK is currently experiencing small earthquakes that are believed to be related to mining activities.&#xA;The British Geological Survey has a page about these events: &lt;a href=&quot;http://www.earthquakes.bgs.ac.uk/earthquakes/recent_events/ollerton_earthquakes.html&quot; rel=&quot;nofollow&quot;&gt;New Ollerton Earthquake Activity.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="419" LastEditorUserId="6093" LastEditDate="2016-09-22T13:59:16.680" LastActivityDate="2016-09-22T13:59:16.680" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="838" PostTypeId="2" ParentId="761" CreationDate="2014-05-07T15:29:11.093" Score="6" Body="&lt;p&gt;We are in the final stages of a new book on numerical particle tracking for the coastal ocean. Originally as part of that book and now separate from it, we have developed an evolving list of routines for particle tracking. It can be access at &lt;a href=&quot;http://www.nefsc.noaa.gov/drifter/particles.html&quot;&gt;http://www.nefsc.noaa.gov/drifter/particles.html&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't mean to detract from the answer by @IRO-bot. I just wanted to complement his results.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edits and extensions can be emailed to James Manning @NOAA&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We provide a list of algorithms that is not meant to be complete. We separate the algorithms into two categories: 1) code run offline using available model results and 2) web-based particle tracking that does not require any execution by the user (point and click). Many of the web-based routines are now being shared and applied in multiple regions of the globe.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Example Offline Particle Tracking Packages&lt;/p&gt;&#xA;  &#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;LTRANS: The Larval TRANSport Lagrangian model is an offline&#xA;  particle-tracking model that uses stored predictions of a 3D&#xA;  hydrodynamic model, specifically the Regional Ocean Modeling System&#xA;  (ROMS). Although LTRANS was built to simulate larvae, it has been&#xA;  adapted to simulate passive particles and other planktonic organisms.&#xA;  LTRANS is written in Fortran 90 and is designed to track the&#xA;  trajectories of particles in three dimensions using a 4th order&#xA;  Runge-Kutta scheme for advection and random displacement to account&#xA;  for vertical turbulence. Contact E. North (U. Maryland),&#xA;  enorth@umces.edu, &lt;a href=&quot;http://northweb.hpl.umces.edu/LTRANS.htm&quot;&gt;http://northweb.hpl.umces.edu/LTRANS.htm&lt;/a&gt;&lt;/li&gt;&#xA;  &lt;li&gt;Ariane: Ariane is an offline computational tool (Fortran 90/95) to calculate 3D streamlines from the output velocity field of&#xA;  a finite difference circulation model such as OPA-NEMO, ROMS, or&#xA;  Symphonie. Contact B. Blanke from IFREMER),&#xA;  Bruno.Blanke@univ-brest.fr,&#xA;  &lt;a href=&quot;http://stockage.univ-brest.fr/~grima/Ariane/&quot;&gt;http://stockage.univ-brest.fr/~grima/Ariane/&lt;/a&gt;&lt;/li&gt;&#xA;  &lt;li&gt;LarvalMap: Is a web service build on a python library that provides a common data model and methods for particle tracking. It&#xA;  was originally developed as a 3D web-based larval fish and&#xA;  invertebrate transport model connected to ROMS circulation fields for&#xA;  the northeast Pacific. It can be used with any Data Access Protocol&#xA;  (DAP) accessible circulation dataset formatted using the network&#xA;  Common Data Format for Climate and Forecast (NetCDF CF). Contact:&#xA;  DevOps@asascience.com.&#xA;  &lt;a href=&quot;https://github.com/asascience-open/paegan-transport&quot;&gt;https://github.com/asascience-open/paegan-transport&lt;/a&gt;&lt;/li&gt;&#xA;  &lt;li&gt;PartTrack: PartTracker is a particle tracking research tool currently being developed in MatlabTM which is designed to be used&#xA;  with both unstructured and structured model grids and has previously&#xA;  been applied to outputs from SELFE (Semi -implicit&#xA;  Eulerian-Lagrangian Finite- Element model) for the purposes of&#xA;  assessing wastewater and larval dispersal. PartTracker applies the&#xA;  time adaptive composite 4th-5th order Runge-Kutta (RK45) numerical&#xA;  scheme to ensure required minimum standards of accuracy are achieved&#xA;  for individual particle paths. The application of the RK45 approach&#xA;  ensures consistency in particle path accuracy across hydrodynamically&#xA;  complex domains and a range of user defined time steps with the time&#xA;  adaptive aspect of the approach reducing computational overheads in&#xA;  hydrodynamically simple flows by allowing for long time steps. Knight&#xA;  BR, Zyngfogel R, Forrest B 2009. PartTracker â€“ a fate analysis tool&#xA;  for marine particles. In Proceedings of Australasian Coasts and Ports&#xA;  Conference 2009. Dawe I, ed. New Zealand Coastal Society, Wellington.&#xA;  pp 8. Contact Ben Knight (Carthron Institute, New Zealand.&lt;/li&gt;&#xA;  &lt;li&gt;WebDrogue: Beta-release Java graphical user interface used to obtain drift predictions from user-specified points in the model&#xA;  domain and can be installed under MS-Windows and Linux. The drift&#xA;  trajectories are computed using circulation derived from the tides,&#xA;  the seasonal mean circulation, wind-driven circulation, and a&#xA;  surface-wind drift (Hannah, et al.2004) Contact: Jason Chaffey at&#xA;  ChaffeyJ@mar.dfo-mpo.gc.ca&#xA;  &lt;a href=&quot;http://www.bio.gc.ca/science/research-recherche/ocean/webdrogue/index-eng.php&quot;&gt;http://www.bio.gc.ca/science/research-recherche/ocean/webdrogue/index-eng.php&lt;/a&gt;&lt;/li&gt;&#xA;  &lt;li&gt;Two-Way PTM: In order to determine the source of particle arriving at one location, particle tracks can be run backwards to&#xA;  determine a probable source, then forward to determine the robustness&#xA;  of the results given a prescribed randomness. This is described in&#xA;  Isobe, et al, 2009, for example, where it is applied to the East&#xA;  China Sea. Contact aisobe@sci.ehime-u.ac.jp&lt;/li&gt;&#xA;  &lt;li&gt;ICTHYOP: Developed to study how physical factors (e.g., currents, water temperature) and biological factors (e.g., egg&#xA;  buoyancy, larva growth) affect the dynamics of fish eggs and larvae.&#xA;  It gathers physicians and biologists together around a common tool,&#xA;  easily available and user-friendly. Contact: info@previmer.org&#xA;  &lt;a href=&quot;http://www.ichthyop.org&quot;&gt;http://www.ichthyop.org&lt;/a&gt;&lt;/li&gt;&#xA;  &lt;li&gt;OILTRANS: &quot;an off-line particle-transport model coupled to the most up to date operational met-ocean model forecasts.&#xA;  Formulations for the dominant oil fate processes of spreading,&#xA;  advection, diffusion, evaporation, emulsi- fication and dispersion&#xA;  have been encoded, providing the model with the ability to accurately&#xA;  predict the horizontal movement of surface oil slick, the vertical&#xA;  entrainment of oil into the water column and the mass balance of&#xA;  spilled oil.&quot; Contact: alan.berry@marine.ies See Berry, A., T.&#xA;  Dabrowski, and K. Lyons. 2012. The oil spill model OILTRANS and its&#xA;  application to the Celtic Sea. Marine Pollution Bulletin. 64 pp.&#xA;  2489-2501. Some documentation reported here.&lt;/li&gt;&#xA;  &lt;li&gt;&lt;p&gt;Sediment Transport: A community models for coastal sediment transport are under development. Some notes on this project are&#xA;  provided here where there is a list of existing models. Contact&#xA;  csherwood@usgs.gov. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Example Web-Based Particle Tracking Routines&lt;/p&gt;&lt;/li&gt;&#xA;  &lt;li&gt;SCCOOS tracks the Monteray Bay flows off California (&lt;a href=&quot;http://ourocean.jpl.nasa.gov/SCB/scbmangen.jsp&quot;&gt;http://ourocean.jpl.nasa.gov/SCB/scbmangen.jsp&lt;/a&gt;)&lt;/li&gt;&#xA;  &lt;li&gt;NCSTATE: tracks flow in large Northwest Atlantic ROMS/HYCOM grid Contact: Ruoying He&#xA;  &lt;a href=&quot;http://omgsrv1.meas.ncsu.edu:8080/ocean-circulation-useast2/trajectory.jsp&quot;&gt;http://omgsrv1.meas.ncsu.edu:8080/ocean-circulation-useast2/trajectory.jsp&lt;/a&gt;)&lt;/li&gt;&#xA;  &lt;li&gt;ALAVAI: Visualization tool for a surface ocean drift forecast. Environmental Modelling and Software. Otero et al., 2013.&#xA;  Contact: Pablo Otero (&lt;a href=&quot;https://github.com/PabloOtero/Alavai&quot;&gt;https://github.com/PabloOtero/Alavai&lt;/a&gt;)&lt;/li&gt;&#xA;  &lt;li&gt;Connie Tool: An â€œonline tool for marine scientists and managers to investigate patterns of marine spatial connectivity. It&#xA;  has been applied in areas such as larval dispersion and recruitment&#xA;  studies, and the development of scenarios and risk assessments for&#xA;  contaminant dispersion.â€ Contact: connie@csiro.au&#xA;  (&lt;a href=&quot;http://www.csiro.au/connie2/&quot;&gt;http://www.csiro.au/connie2/&lt;/a&gt;)&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2014-05-07T15:47:10.663" LastActivityDate="2014-05-07T15:47:10.663" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="839" PostTypeId="1" AcceptedAnswerId="843" CreationDate="2014-05-07T15:39:42.560" Score="3" ViewCount="3249" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Per Oxford Dictionary of Earth Sciences&lt;/strong&gt;: Seamounts are isolated, submarine mountain rising more than 1000m above the&#xA;  ocean floor. The sharp, crested summits of seamounts are usually&#xA;  1000-2000m below the ocean surface. Seamounts are of volcanic origin.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/835/284&quot;&gt;Per kaberett&lt;/a&gt;:&lt;/strong&gt; To avoid classifying seamounts by arbitrary sea level (dependent on availability of surface water), the key point is&#xA;  then that seamounts are features of volcanic origin that rise over&#xA;  1000m above oceanic crust.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Seamount&quot; rel=&quot;nofollow noreferrer&quot;&gt;Per Wikipedia&lt;/a&gt;:&lt;/strong&gt; A seamount is a mountain rising from the ocean seafloor that does not reach to the water's surface (sea level), and&#xA;  thus is not an island.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;http://www.oxforddictionaries.com/us/definition/american_english/submarine?q=submarine&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Per Oxford Dictionary:&lt;/strong&gt;&lt;/a&gt; Submarine means &quot;Existing, occurring,&#xA;  done, or used under the surface of the sea.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Per NOAA:&lt;/strong&gt; A seamount is an underwater mountain on the seafloor.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Are all seamounts below the water, or do they include formations that rise above the water?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE:&lt;/strong&gt; Atolls not within the scope of defining formations that rise above the water; meaning atolls are atolls, and not seamount crests.&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-05-07T17:23:09.747" Title="What is a seamount?" Tags="|mountains|sea-level|" AnswerCount="2" CommentCount="19" ClosedDate="2014-05-07T17:28:40.477" ContentLicense="CC BY-SA 3.0" />
  <row Id="840" PostTypeId="2" ParentId="839" CreationDate="2014-05-07T16:38:28.880" Score="1" Body="&lt;p&gt;&lt;a href=&quot;https://darchive.mblwhoilibrary.org/handle/1912/3553&quot; rel=&quot;nofollow&quot;&gt;Staudigel &lt;em&gt;et al&lt;/em&gt;. (2010)&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The term seamount has been defined many times (e.g., Menard, 1964; Wessel, 2001; Schmidt and Schmincke, 2000; Pitcher et al., 2007; International Hydrographic Organization, 2008; Wessel et al., 2010) but there is no “generally accepted” definition. Instead, most definitions serve the particular needs of a discipline or a specific paper. [...] As we explore the major differences among definitions of the term “seamount,” several important issues play a role:&lt;/p&gt;&#xA;  &#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;The inclusion of the temporarily emergent portions of seamounts is relatively obvious for geologists who look at seamount construction over long time scales. Many large seamounts either have summit regions that currently breach sea level, or at some point they emerged and are now entirely submerged. Hence, temporary emergence is part of the life cycle of many very large seamounts. The inclusion of emerged summits, however, is counter intuitive for a biologist. Biological communities on land are dramatically different from submerged communities and, hence, data from the emerged fractions of a seamount cannot be reasonably included into a focused marine biological study. The complexity of this issue is illustrated by Lō'ihi Seamount (see Spotlight 3 on page 72 of this issue [Staudigel et al., 2010]), an entirely submerged seamount that is located on the submarine flank of Mauna Loa, the largest&#xA;  volcano of the Hawaiian Islands.&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;  &#xA;  &lt;p&gt;[...]&lt;/p&gt;&#xA;  &#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;Some seamount definitions also include aspects of their shape, in particular, restricting their use to conical features, whereby flat-topped (“tablemount”) seamounts are commonly called guyots. This morphological distinction is significant insofar as flat-topped seamounts are likely to once have been islands or coral reefs, while conical ones are likely to not to have breached the sea surface during their life cycle (Staudigel and Clague, 2010).&lt;/li&gt;&#xA;  &lt;li&gt;In their original definition, seamounts were defined based on&#xA;  their tectonic setting, specifically, as features on the seafloor&#xA;  that are not part of mid-ocean ridges or subduction zones&#xA;  (Menard, 1964). This limitation to intraplate volcanoes pays&#xA;  tribute to the distinct magmatic processes that form volcanoes&#xA;  at mid-ocean ridges, arc volcanoes, and in intraplate settings.&#xA;  Apparent exceptions are mantle hotspots located at or close&#xA;  to mid-ocean ridges, such as the one presumed to exist under&#xA;  Axial Seamount at the Juan de Fuca Ridge (see Spotlight 1 on&#xA;  page 38 of this issue [Chadwick et al., 2010]) that appears to&#xA;  be the origin of the Cobb seamount chain. Wessel et al. (2010)&#xA;  restrict their use of the term seamount to intraplate features,&#xA;  excluding arc volcanoes in their seamount count.&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Full citation: Staudigel, H., A.A.P. Koppers, J.W. Lavelle, T.J. Pitcher, and T.M. Shank. 2010. Box 1: Defining the word &quot;seamount&quot;. Oceanography 23(1):20–21, &lt;a href=&quot;http://dx.doi.org/10.5670/oceanog.2010.85&quot; rel=&quot;nofollow&quot;&gt;http://dx.doi.org/10.5670/oceanog.2010.85&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="105" LastEditorUserId="105" LastEditDate="2014-05-07T16:56:10.947" LastActivityDate="2014-05-07T16:56:10.947" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="842" PostTypeId="2" ParentId="834" CreationDate="2014-05-07T16:54:54.700" Score="12" Body="&lt;p&gt;This answers &lt;em&gt;one&lt;/em&gt; of the questions you list, but the &lt;em&gt;shallowest&lt;/em&gt; seamount, per &lt;a href=&quot;http://en.wikipedia.org/wiki/List_of_submarine_volcanoes&quot;&gt;this list on Wikipedia&lt;/a&gt; is &lt;a href=&quot;http://en.wikipedia.org/wiki/Banua_Wuhu&quot;&gt;Banua Wahu&lt;/a&gt;, which is 8 meters below the surface, but has risen above the surface and fallen below the surface several times in recorded history.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this is definitely &lt;em&gt;not&lt;/em&gt; the tallest seamount, standing only 400m high from its base.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit&lt;/strong&gt;&lt;br/&gt;&#xA;A larger database by &lt;a href=&quot;http://doi.pangaea.de/10.1594/PANGAEA.757562&quot;&gt;Yesson, C et al.&lt;/a&gt; includes several seamounts that are within 2 meters of the surface.  However, the data does not suggest when the measurements were taken (high tide or low tide), which would have obvious implications.  Also, there are many seamounts within that range (I stopped counting at 100).&lt;/p&gt;&#xA;" OwnerUserId="330" LastEditorUserId="330" LastEditDate="2014-05-07T19:40:55.407" LastActivityDate="2014-05-07T19:40:55.407" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="843" PostTypeId="2" ParentId="839" CreationDate="2014-05-07T17:12:29.053" Score="6" Body="&lt;p&gt;A seamount is, quite simply:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;an underwater mountain rising above the ocean floor&lt;br/&gt;&#xA;  &lt;a href=&quot;http://quizlet.com/6969668/5th-grade-science-vocabulary-sa-flash-cards/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The term, however, does not have scientific consensus.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/839/330&quot;&gt;Some definitions&lt;/a&gt; include only formations over 1km in height, while &lt;a href=&quot;https://earthscience.stackexchange.com/a/841/330&quot;&gt;some&lt;/a&gt; include formations as short as 100m.  Some definitions say that the formation must be exclusively underwater, while &lt;a href=&quot;http://en.wikipedia.org/wiki/Seamount#Geology&quot; rel=&quot;nofollow noreferrer&quot;&gt;other definitions&lt;/a&gt; include the the rise of the formation above the sea floor, even to the point of forming an island.  &lt;a href=&quot;http://www.whoi.edu/main/topic/seamounts&quot; rel=&quot;nofollow noreferrer&quot;&gt;Some definitions&lt;/a&gt; even include islands within the definition of seamount.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the end, a &quot;seamount&quot; has to be defined within each study that uses it, since there is no consensus on whether to include super-surface formations.&lt;/p&gt;&#xA;" OwnerUserId="330" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-05-07T17:12:29.053" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="844" PostTypeId="1" AcceptedAnswerId="847" CreationDate="2014-05-07T18:42:43.617" Score="7" ViewCount="269" Body="&lt;p&gt;Appears that answering &lt;a href=&quot;https://earthscience.stackexchange.com/questions/839/what-is-a-seamount&quot;&gt;what seamounts are is a non-trivial question&lt;/a&gt;. My take is what matters is data, since authoritative opinions on the topic are at best subjective. As such, my position is the definition used by the largest (utilized) database of seamounts would be the best source understanding what seamounts are and are not. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;What is the largest utilised database of seamounts? &lt;/li&gt;&#xA;&lt;li&gt;What definition is used by the largest utilised databases of seamounts to define seamounts?&lt;/li&gt;&#xA;&lt;li&gt;Does it include formations that are above water? &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="284" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-05-08T12:47:46.473" Title="What definition of &quot;seamount&quot; is used by the largest utilised databases of seamounts?" Tags="|oceanography|mountains|sea-level|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="845" PostTypeId="1" AcceptedAnswerId="846" CreationDate="2014-05-07T18:47:09.017" Score="16" ViewCount="954" Body="&lt;p&gt;According to &lt;a href=&quot;http://iceagenow.info/2012/04/volcanic-activity-increasing/&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt; person's surmises, volcanic activity appers to be increasing.&lt;br/&gt;&#xA;However, according to &lt;a href=&quot;http://www.volcano.si.edu/faq.cfm/&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt; report, volcanic activity is probably not increasing.&lt;br/&gt;&lt;br/&gt;&#xA;My question is:&lt;br/&gt;&#xA;Does Volcanic activity fluctuate?&lt;br/&gt;&#xA;If it does, what would cause this fluctuation in volcanic activity?&lt;br/&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image cited by both:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/oIPI7.png&quot; alt=&quot;Volcanic activity over time&quot;&gt;&lt;br/&gt;&#xA;&lt;a href=&quot;http://www.volcano.si.edu/faq.cfm/&quot; rel=&quot;noreferrer&quot;&gt;Image: Smithsonian National Museum of Natural History, Global Volcanism Program&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this fluctuation or recording increase?&lt;/p&gt;&#xA;" OwnerUserId="116" LastEditorUserId="116" LastEditDate="2014-05-08T16:15:09.850" LastActivityDate="2018-05-08T15:56:57.443" Title="Does volcanic activity fluctuate?" Tags="|geophysics|volcanology|geodynamics|volcanoes|geothermal-heat|" AnswerCount="6" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="846" PostTypeId="2" ParentId="845" CreationDate="2014-05-07T19:09:56.413" Score="16" Body="&lt;p&gt;This is probably an observational effect that is quite common in the Earth Sciences. In scientifically progressing societies there is a higher proportion of observations due to a number of effects:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;awareness of science (not interpreting it as a wonder)&lt;/li&gt;&#xA;&lt;li&gt;ability to record events&lt;/li&gt;&#xA;&lt;li&gt;ability to observe (think 12 hour day in the factory vs. free weekend)&lt;/li&gt;&#xA;&lt;li&gt;technology to do remote observations&lt;/li&gt;&#xA;&lt;li&gt;...&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;This is also why more and more meteorites are observed falling. In the middle ages you were either too busy to care, took it as a wonder, or found a meteorite, but had no ability to write it down. Similar scenario for volcanic eruptions. I could imagine that actually all those ships, airplanes, and oudoor-activities (no offense) lead to more observations of eruptions, but that people were to busy recording and writing them down. The geologists of their time were probably busy finding war-necessary resources.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sources:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.volcanodiscovery.com/de/volcanoes/faq/is-volcanic-activity-increasing.html&quot;&gt;http://www.volcanodiscovery.com/de/volcanoes/faq/is-volcanic-activity-increasing.html&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="23" LastActivityDate="2014-05-07T19:09:56.413" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="847" PostTypeId="2" ParentId="844" CreationDate="2014-05-07T19:36:32.960" Score="9" Body="&lt;p&gt;The largest database of seamounts contains over 33,000 seamounts and was created by Yesson, Chris; Clark, MR; Taylor, M; Rogers, AD.  &lt;a href=&quot;http://doi.pangaea.de/10.1594/PANGAEA.757562&quot;&gt;Link&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For their list, they defined seamounts and knolls as &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Seamounts and knolls are 'undersea mountains', the former rising more than 1000 m from the sea floor&lt;br/&gt;&#xA;  &lt;a href=&quot;http://doi.pangaea.de/10.1594/PANGAEA.757564&quot;&gt;Yesson, C et al. (2011): Lists of seamounts and knolls in different formats. doi:10.1594/PANGAEA.757564&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0967063711000392&quot;&gt;their paper&lt;/a&gt;, they set the definition of a seamount as a sub-surface feature, not breaking the water.  This puts the highest elevation in their dataset is 2m below sea level.  The pulled their definition from &lt;a href=&quot;http://www.int-res.com/articles/meps2008/357/m357p017.pdf&quot;&gt;Morato, et al (2008)&lt;/a&gt;, which states: &quot;seamounts are defined as any topographically distinct seafloor feature that is at least 200 m higher than the surrounding seafloor, but which does not break the sea surface.&quot;  Then, they subdivided the features into knolls and seamounts at an heigh of 1km (with knolls being between 200m and 1km in height).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, specifically answering the question, that databases uses the &lt;a href=&quot;http://www.int-res.com/articles/meps2008/357/m357p017.pdf&quot;&gt;Morato, et al (2008)&lt;/a&gt; definition, which excludes super-surface seamounts.&lt;/p&gt;&#xA;" OwnerUserId="330" LastEditorUserId="330" LastEditDate="2014-05-08T12:47:46.473" LastActivityDate="2014-05-08T12:47:46.473" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="849" PostTypeId="1" CreationDate="2014-05-05T06:36:05.330" Score="-5" ViewCount="244" Body="&lt;p&gt;This idea keeps on appearing in my mind, once in a million years the Sun's gravity will pull Earth near and eliminate every living in the earth due to the increased heat, and in another million years it pushes Earth far away and creates a frozen age due to lack of heat?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;My Theory 1&lt;/strong&gt;&#xA;I know that earth orbit around the sun is because of sun gravity, but gravity is randomly based on unknow mechanic, it might strong today, and might be weak after few years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I say that Ice age form is because the earth slowly move away from the sun million years ago(unexplainable weak sun gravity), lack of sunlight to the earth make earth cold,&#xA;And now the ice at north pole is melting, it means that we might actually getting closer to the sun. And the event will keep on repeat each hundred million years, so we in the middle of extinction process, but that will take hundred million years to reach a level where the sun ray can destroy everything&#xA;I know is kinda bluff without any proof, but this might be one of the possibility&lt;/p&gt;&#xA;" OwnerDisplayName="Se0ng11" LastEditorUserId="87" LastEditDate="2014-11-19T15:12:43.350" LastActivityDate="2014-11-19T15:12:43.350" Title="Is there another explanation than an asteroid/volcano for the extinction event on Earth millions of years ago?" Tags="|planetary-science|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="850" PostTypeId="2" ParentId="849" CreationDate="2014-05-05T10:59:32.217" Score="13" Body="&lt;p&gt;Look at &lt;a href=&quot;http://en.m.wikipedia.org/wiki/Earth%27s_orbit&quot;&gt;Earth's orbit&lt;/a&gt; around the Sun. The orbit is an ellipse, but Earth never gets close enough for the Sun to cause any mass extinction. The Earth orbits the Sun every year, and because the orbit is stable, on average we are about 8 light minutes from the Sun. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One way the Earth's orbit might change is if the Sun has a sister companion, that is, a &lt;a href=&quot;http://en.m.wikipedia.org/wiki/Binary_Star&quot;&gt;binary star&lt;/a&gt;; thus far no evidence suggests the existence of another star in our solar system, but a binary star could alter the orbit of a planet. You could become an Astronomer and try to prove your hypothesis and it would not be a wasted journey.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;I see you edited your question&lt;/strong&gt;. Now you have included some aspects about gravity which contradict current knowledge of gravity. I highly recommend reading about &lt;a href=&quot;http://en.wikipedia.org/wiki/Law_of_Gravity&quot;&gt;gravity&lt;/a&gt;. To start you off I will share with you a known fact about gravity. The Earth exerts the same gravitational force on the Sun that the Sun exerts on the Earth. $$F_1=F_2 = G *m_1*m_2/r^2$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is, both these objects attract each other with the same amount of force. Moreover, gravity is related to an objects mass, so unless the Sun or the Earth lost mass there would be no change.&lt;/p&gt;&#xA;" OwnerUserId="430" OwnerDisplayName="FunctionR" LastActivityDate="2014-05-06T09:18:18.730" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="851" PostTypeId="2" ParentId="849" CreationDate="2014-05-05T18:13:59.097" Score="6" Body="&lt;p&gt;There have been numerous &lt;a href=&quot;https://en.wikipedia.org/wiki/Mass_extinction&quot;&gt;mass extinctions&lt;/a&gt; in Earth's history. The most famous one took place about 66 million years ago; see the linked article for others. Different events likely had different causes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You suggest that the Sun's gravity periodically pulls the Earth closer, and then pushes it away. As far as I know, there is no evidence that this could have happened. The Sun's mass slowly diminishes over billions of years, due to direct loss of mass via solar wind and conversion of mass to energy; this should cause the Earth's orbit to expand &lt;em&gt;very&lt;/em&gt; slowly. There is no known mechanism by which a change in the Sun's mass could draw the Earth closer and then &quot;push&quot; it away -- nor is there any need to postulate such a mechanism, since there are no observed phenomena that need it as an explanation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do you have some specific reason to think your idea is plausible?&lt;/p&gt;&#xA;" OwnerUserId="429" OwnerDisplayName="Keith Thompson" LastActivityDate="2014-05-05T18:13:59.097" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="852" PostTypeId="2" ParentId="783" CreationDate="2014-05-08T13:52:18.087" Score="12" Body="&lt;p&gt;Complementing the answer by @seismo_steve, two other geophysical ways of&#xA;detecting magma chambers are through their density and conductivity anomalies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seismic tomography is able to detect the chambers because they cause an anomaly&#xA;in the propagation velocity of seismic waves.&#xA;Likewise, the chambers cause an &lt;strong&gt;anomaly in the gravity field&lt;/strong&gt; because&#xA;their density is different from the surrounding/reference value.&#xA;Geophysicists can use this gravity anomaly to estimate the size and shape of&#xA;the magma chamber&#xA;(see &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2013JB010168/abstract&quot;&gt;this paper by Chaves and Ussami, 2013, for an example also in Yellowstone&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Long-wavelength &lt;strong&gt;electromagnetic methods&lt;/strong&gt;, like&#xA;&lt;a href=&quot;http://en.wikipedia.org/wiki/Magnetotellurics&quot;&gt;magnetotellurics&lt;/a&gt;,&#xA;might also be able to detect the electrical conductivity anomaly associated&#xA;with the magma chamber (though there are some restrictions).&#xA;See &lt;a href=&quot;http://library.seg.org/doi/abs/10.1190/1.1441987&quot;&gt;this classic paper by Newman et al. (1985)&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="137" LastActivityDate="2014-05-08T13:52:18.087" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="853" PostTypeId="2" ParentId="332" CreationDate="2014-05-08T14:10:09.120" Score="7" Body="&lt;p&gt;It depends on which classification system you're using, which varies by country. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;According to the &lt;a href=&quot;http://www.nrcs.usda.gov/wps/portal/nrcs/main/soils/survey/class/&quot; rel=&quot;nofollow&quot;&gt;USDA Soil Taxonomy&lt;/a&gt;, R is used to designate bedrock&lt;/strong&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other countries and classification systems may (or may not) use different letters. Check out the &lt;a href=&quot;http://www.itc.nl/~rossiter/research/rsrch_ss_class.html&quot; rel=&quot;nofollow&quot;&gt;Compendium of On-Line Soil Survey Information&lt;/a&gt; for other classification systems. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer your second question, there are standards, depending on which classification system or country or even discipline you're in. Soil scientists in the US use the USDA soil taxonomy, or R to designate bedrock. &lt;/p&gt;&#xA;" OwnerUserId="383" LastEditorUserId="383" LastEditDate="2014-11-21T15:29:11.473" LastActivityDate="2014-11-21T15:29:11.473" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="855" PostTypeId="2" ParentId="845" CreationDate="2014-05-08T15:15:22.590" Score="13" Body="&lt;p&gt;Whether volcanic activity fluctuates depends rather on the timescales you are looking at. &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/0377027384900398&quot; rel=&quot;nofollow noreferrer&quot;&gt;Crisp (1984)&lt;/a&gt; compiles available data on igneous activity lasting for longer than 300 years and concludes that over the past 180 million years the annual average magmatic output each year is around 30km&lt;sup&gt;3&lt;/sup&gt;, of which ~75% is produced at mid-ocean ridges.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most obvious variability in magmatic output arises from flood basalt eruptions, frequently correlated with continental rifting, and suggested to result from the first impact of a new hot upwelling mantle plume. These are enormous events - circa 10&lt;sup&gt;6&lt;/sup&gt;km&lt;sup&gt;3&lt;/sup&gt; of magma emplaced over timescales as short as one million years and always less than 10 million years - and even though they account for &gt;95% of intracontinental volcanism, they account for only circa 5% of the global magmatic output due to their rarity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, yes, on short timescales volcanic activity can and does fluctuate - output rates are generally higher while Large Igneous Province emplacement is ongoing - and indeed on very long timescales (if the Earth was a magma ocean in its early history, it had more volcanic activity than the modern surface does!). However, on medium timescales - the ones geologists are typically interested in - the average output rates are fairly stable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As &lt;a href=&quot;https://earthscience.stackexchange.com/a/631/105&quot;&gt;has been mentioned&lt;/a&gt; &lt;a href=&quot;http://www.usgs.gov/faq/categories/9830/3355&quot; rel=&quot;nofollow noreferrer&quot;&gt;with respect to earthquakes&lt;/a&gt;, earthquakes are &lt;em&gt;not&lt;/em&gt; increasing in frequency. The key points, as with earthquakes, are improved technology and increased population density. Increased population density results in more events being observed, and individual events having greater negative impact; improvements in technology make it easier to perform remote observation, and to identify remote eruptions in the geological past. In particular, work with Antarctic ice cores (we have records going back 800,000 years at this point, and work is ongoing on a million-year core!) allow identification of discrete eruptions because they deposit layers of fine ash or, from further away, acid-rich layers. These eruptions can be correlated with one another between different cores - and even ice cores taken from different continents - through massive &quot;marker&quot; eruptions, such as Krakatoa, and to some extent through absolute dating via isotope chemistry in air bubbles trapped within the ice. However, even as our ability to interpret ice cores further and further back improves, our estimates of global magmatic activity stay pretty constant: despite being published 30 years ago, Joy Crisp's paper is still considered a decent piece of work worth citing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;ETA&lt;/strong&gt; I note that the first report you cite, at &quot;iceagenow.com&quot;, says about the author:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Felix is not affiliated with any university, scientific establishment, or corporation, and therein lies his strength. Untainted by institutional bias or conventional wisdom this architect turned author brings fresh insight to the study of the ice ages.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I suggest that he is probably less reliable than scientific consensus; peer review has its flaws but does exist for a reason! If you would like a close reading and critique of his report, can you make that clear? Cheers :-) &lt;/p&gt;&#xA;" OwnerUserId="105" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-11-16T18:27:58.707" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="856" PostTypeId="1" AcceptedAnswerId="859" CreationDate="2014-05-08T15:19:34.753" Score="17" ViewCount="11242" Body="&lt;p&gt;Radioactive element &lt;code&gt;A&lt;/code&gt; radioactively decays into material &lt;code&gt;B&lt;/code&gt;. If 75% of &lt;code&gt;A&lt;/code&gt; and 25% of &lt;code&gt;B&lt;/code&gt; are present, how many half-lives of material &lt;code&gt;A&lt;/code&gt; have elapsed?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was recently taught that the correct answer is &quot;one half of a half-life has elapsed&quot;. However, due to the fact that the amount of radioactive material remaining scales exponentially (logarithmically) instead of in a linear fashion, wouldn't the answer be less than one half of a half-life?&lt;/p&gt;&#xA;" OwnerUserId="153" LastEditorUserId="153" LastEditDate="2014-05-14T12:43:10.253" LastActivityDate="2014-11-03T01:58:17.000" Title="If 75% of radioactive material remains, how many half-lives have elapsed?" Tags="|measurements|radioactivity|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="857" PostTypeId="2" ParentId="856" CreationDate="2014-05-08T15:28:28.813" Score="15" Body="&lt;p&gt;You can use simple logarithms to calculate the answer.  The number of half-lives that have elapsed can be calculated with&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA; - \frac{\log{f}}{\log{2}}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $f$ is the fraction that remains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So plugging in the numbers gives&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;- \frac{\log(0.75)}{\log(2)} = 0.415 = 41.5\%&#xA;$$&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2014-05-08T15:28:28.813" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="858" PostTypeId="1" CreationDate="2014-05-08T15:40:27.820" Score="27" ViewCount="557" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Sting_jet&quot; rel=&quot;noreferrer&quot;&gt;Sting jets&lt;/a&gt; are thought to be responsible for some of the most damaging winds associated with extratropical cyclones in the mid-latitudes. So far they have only been confirmed in the European region, associated with the &lt;a href=&quot;https://en.wikipedia.org/wiki/Extratropical_cyclone#Shapiro-Keyser_model&quot; rel=&quot;noreferrer&quot;&gt;Shapiro-Keyser model&lt;/a&gt; of cyclone development. They have been considered to be much less important in storms forming in the Pacific which can impact the west coast of North America, though new studies indicate that they are theoretically possible, and likely occur in this region. (&lt;a href=&quot;http://www.met.reading.ac.uk/~rb904381/ExeterWind2013_NeilHart.pdf&quot; rel=&quot;noreferrer&quot;&gt;Do North Pacific sting jet cyclones exist?&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Two sting jets have been &lt;a href=&quot;http://earthzine.org/2012/11/27/cloud-features-and-mesoscale-structure-of-non-convective-high-wind-events/&quot; rel=&quot;noreferrer&quot;&gt;postulated&lt;/a&gt; as having occurred over the (continental) Midwest USA though. Given that the Shapiro-Keyser model is applied to oceanic cyclones, is it theoretically possible that these continental forming sting jets are genuine sting jet cases?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know if the sting jet &lt;a href=&quot;http://www.atl.ec.gc.ca/weather/hurricane/bulletins/20140706143840.Arthur.info.txt.en&quot; rel=&quot;noreferrer&quot;&gt;identified&lt;/a&gt; over the Canadian Maritimes from &lt;a href=&quot;http://en.wikipedia.org/wiki/Hurricane_Arthur_(2014)&quot; rel=&quot;noreferrer&quot;&gt;ex-hurricane Arthur 2014&lt;/a&gt; technically nullifies this question, but I think it remains valid for those storms in the continental centre of North America.&lt;/p&gt;&#xA;" OwnerUserId="140" LastEditorDisplayName="user12525" LastEditDate="2019-04-18T11:22:18.173" LastActivityDate="2023-07-04T18:53:32.563" Title="Is it possible for a sting jet to form over a continental landmass?" Tags="|meteorology|wind|atmospheric-circulation|mesoscale-meteorology|jet-stream|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="859" PostTypeId="2" ParentId="856" CreationDate="2014-05-08T16:44:59.893" Score="25" Body="&lt;p&gt;@gerrit provided a formula, but without stating the reasoning behind it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Radioactive decay is an exponential function.  After $n$ half-lives, the amount of the original material remaining is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\textrm{amount remaining after}\ n\ \textrm{half-lives} = \left(\frac{1}{2}\right)^n$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, you want to solve&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\begin{align*}&#xA;\left(\frac{1}{2}\right)^n &amp;amp;= \frac{3}{4}\\&#xA;\log_\frac{1}{2} \left(\frac{1}{2}\right)^n &amp;amp;= \log_\frac{1}{2} \frac{3}{4}\\&#xA;n &amp;amp;= \frac{\log \frac{3}{4}}{\log \frac{1}{2}} = \frac{\log \frac{3}{4}}{- \log 2}&#xA;   \approx 0.415&#xA;\end{align*}$$&lt;/p&gt;&#xA;" OwnerUserId="431" LastEditorUserId="431" LastEditDate="2014-11-03T01:58:17.000" LastActivityDate="2014-11-03T01:58:17.000" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="860" PostTypeId="1" CreationDate="2014-05-08T21:45:07.273" Score="13" ViewCount="141" Body="&lt;p&gt;I have visited storage- and test facilities that are within salt and clay (Opalinuston) lithologies. What are other lithologies that are considered for the storage of nuclear waste and what are their advantages?&lt;/p&gt;&#xA;" OwnerUserId="23" LastEditorDisplayName="user20559" LastEditDate="2021-05-13T14:44:45.877" LastActivityDate="2021-05-13T14:44:45.877" Title="What lithologies are deemed most suitable for the storage of nuclear waste" Tags="|geology|petrology|" AnswerCount="1" CommentCount="3" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="861" PostTypeId="1" AcceptedAnswerId="925" CreationDate="2014-05-08T23:41:04.607" Score="12" ViewCount="108" Body="&lt;p&gt;In atmospheric remote sensing of methane, a dominant source of error is the uncertainty in spectroscopic parameters.  For example, in the retrieval algorithms described by Batchelor et al. (2009), the CH₄ error due to line intensities is estimated at 16.5% (dominating the total error of 16.8%), versus 10.5% for O₃, 3.8% for N₂O, and only 1.6% for HCl.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The article documenting the 2012 HITRAN spectroscopic database update (Rothman et al., 2013) states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;High-resolution spectroscopy of methane and the generation of accurate line lists, especially as one moves up the polyad ladder to shorter and shorter wavelength (necessary for many applications) is extremely challenging.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The 2012 edition includes a very large update on methane measurements, as detailed by Brown et al. (2013), who describe how the number of HITRAN methane lines has increased from 11,803 in the 1982 edition, via 251,440 in the 2004 edition, to 468,013 in the 2012 edition.  However, neither Rothman et al. (2013) nor Brown et al. (2013) describe &lt;em&gt;why&lt;/em&gt; the determination of methane spectroscopic parameters is so difficult.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why are methane spectroscopic parameters harder to determine (and therefore more poorly known) compared to other common Earth atmospheric trace gases?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Batchelor, Rebecca L., Kimberly Strong, Rodica Lindenmaier, Richard L. Mittermeier, Hans Fast, James R. Drummond, and Pierre F. Fogal. &quot;A New Bruker IFS 125HR FTIR Spectrometer for the Polar Environment Atmospheric Research Laboratory at Eureka, Nunavut, Canada: Measurements and Comparison with the Existing Bomem DA8 Spectrometer.&quot; Journal of Atmospheric &amp;amp; Oceanic Technology 26, no. 7 (2009).&lt;/li&gt;&#xA;&lt;li&gt;L.S. Rothman, I.E. Gordon, Y. Babikov, A. Barbe, D. Chris Benner, P.F. Bernath, M. Birk, L. Bizzocchi, V. Boudon, L.R. Brown, A. Campargue, K. Chance, E.A. Cohen, L.H. Coudert, V.M. Devi, B.J. Drouin, A. Fayt, J.-M. Flaud, R.R. Gamache, J.J. Harrison, J.-M. Hartmann, C. Hill, J.T. Hodges, D. Jacquemart, A. Jolly, J. Lamouroux, R.J. Le Roy, G. Li, D.A. Long, O.M. Lyulin, C.J. Mackie, S.T. Massie, S. Mikhailenko, H.S.P. Müller, O.V. Naumenko, A.V. Nikitin, J. Orphal, V. Perevalov, A. Perrin, E.R. Polovtseva, C. Richard, M.A.H. Smith, E. Starikova, K. Sung, S. Tashkun, J. Tennyson, G.C. Toon, Vl.G. Tyuterev, G. Wagner, The HITRAN2012 molecular spectroscopic database, Journal of Quantitative Spectroscopy and Radiative Transfer, Volume 130, November 2013, Pages 4-50, ISSN 0022-4073, &lt;a href=&quot;http://dx.doi.org/10.1016/j.jqsrt.2013.07.002&quot;&gt;http://dx.doi.org/10.1016/j.jqsrt.2013.07.002&lt;/a&gt;.&#xA;(&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0022407313002859&quot;&gt;http://www.sciencedirect.com/science/article/pii/S0022407313002859&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;L.R. Brown, K. Sung, D.C. Benner, V.M. Devi, V. Boudon, T. Gabard, C. Wenger, A. Campargue, O. Leshchishina, S. Kassi, D. Mondelain, L. Wang, L. Daumont, L. Régalia, M. Rey, X. Thomas, Vl. G. Tyuterev, O.M. Lyulin, A.V. Nikitin, H.M. Niederer, S. Albert, S. Bauerecker, M. Quack, J.J. O’Brien, I.E. Gordon, L.S. Rothman, H. Sasada, A. Coustenis, M.A.H. Smith, T. Carrington Jr., X.-G. Wang, A.W. Mantz, P.T. Spickler, Methane line parameters in the HITRAN2012 database, Journal of Quantitative Spectroscopy and Radiative Transfer, Volume 130, November 2013, Pages 201-219, ISSN 0022-4073, &lt;a href=&quot;http://dx.doi.org/10.1016/j.jqsrt.2013.06.020&quot;&gt;http://dx.doi.org/10.1016/j.jqsrt.2013.06.020&lt;/a&gt;. (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0022407313002744&quot;&gt;http://www.sciencedirect.com/science/article/pii/S0022407313002744&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2014-05-08T23:58:16.147" LastActivityDate="2014-05-14T13:23:04.290" Title="Why are methane spectroscopic parameters harder to determine and relatively poorly known, compared to other Earth trace gases?" Tags="|atmosphere|methane|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="862" PostTypeId="2" ParentId="856" CreationDate="2014-05-09T00:54:43.730" Score="16" Body="&lt;p&gt;The other answers are entirely correct.  But I like graphical representations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;http://en.wikipedia.org/wiki/Radioactive_decay&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://en.wikipedia.org/wiki/Radioactive_decay&lt;/a&gt; we see the decay formula is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$N(t) = N_0e^\frac{-t}{τ}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where N&lt;sub&gt;0&lt;/sub&gt; is the starting number of nuclides and τ is the mean lifetime.  We also see that the half-life is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$t_{1/2} = τ ln(2)$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Substituting for τ, we get:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$N(t) = N_0e^\frac{-tln(2)}{t_{1/2}}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So for example if we have N&lt;sub&gt;0&lt;/sub&gt; = 1000 and t&lt;sub&gt;1/2&lt;/sub&gt; = 100 we can plot the following graph:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/1Pk80.png&quot; alt=&quot;Exponential decay plot&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Note that the horizontal axis is the t-axis.&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We see the following:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;At t=100 (one half life), N(t) is 500, half of 1000, as expected&lt;/li&gt;&#xA;&lt;li&gt;At t=200 (two half lives), N(t) is 250, 1/4 of 1000, as expected&lt;/li&gt;&#xA;&lt;li&gt;We intersect the curve with a line at N(t) = 750.  Here we can see this occurs at about t=41.5 as predicted by the other answers.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="438" LastEditorUserId="431" LastEditDate="2014-05-09T05:44:51.227" LastActivityDate="2014-05-09T05:44:51.227" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="863" PostTypeId="2" ParentId="436" CreationDate="2014-05-09T01:20:04.220" Score="12" Body="&lt;p&gt;The most accepted theory is that the Younger Dryas was caused by a large reduction or shutdown of the North Atlantic &quot;Conveyor&quot; because of a sudden influx of fresh water from Lake Agassiz and deglaciation in North America. &#xA;(Although evidence for such an event is thus far lacking.) The global climate would then have become locked into this new state until freezing removed the fresh water &quot;lid&quot; from the north Atlantic Ocean. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another theory suggests that the jet stream shifted northward in response to the changing topographic forcing of the melting North American ice sheet, which then brought more rain to the North Atlantic which freshened the ocean surface enough to slow the thermohaline circulation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://geosciencesocietysio.wordpress.com/2014/05/04/paleoclimate-what-caused-the-younger-dryas-event/&quot;&gt;http://geosciencesocietysio.wordpress.com/2014/05/04/paleoclimate-what-caused-the-younger-dryas-event/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="115" LastEditorUserId="115" LastEditDate="2014-11-19T22:46:40.717" LastActivityDate="2014-11-19T22:46:40.717" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="864" PostTypeId="1" CreationDate="2014-05-09T12:12:46.173" Score="11" ViewCount="272" Body="&lt;p&gt;Radiometric dating relies on past isotope ratio predictions being very reliable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this is not necessarily so. For example, in Uranium forensics, &lt;sup&gt;235&lt;/sup&gt;U and &lt;sup&gt;238&lt;/sup&gt;U ratios are about the same for all sources, but &lt;sup&gt;234&lt;/sup&gt;U varies and can sometimes be used to identify the source region. So, how can we be so sure that the isotope ratios used for radiometric dating are as reliable as we assume. What if the ratios of &lt;sup&gt;238&lt;/sup&gt;U and &lt;sup&gt;235&lt;/sup&gt;U we observe are a signature of the earth, like U234 is a signature of geographical regions?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, for meteorites, scientists say that the radiometric dating shows when the rock was last melted. Well, what if it was melted more than once? Does each melting reset the isotope ratios in the rock? If a rock of 4 billion years was fully melted, what happens to the isotope ratios in the rock? In pages that explain radiometric dating, that I have read, don't even mention this scenario - or the following one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And what about the assumption that we can predict the isotopic ratios of the solar system 4 billion years ago? how is the assumption justified?&lt;/p&gt;&#xA;" OwnerUserId="385" LastEditorDisplayName="user20559" LastEditDate="2021-05-26T14:06:24.773" LastActivityDate="2021-05-26T14:06:24.773" Title="How can scientists be confident of isotope ratios in past eras and varied locations, used for radiometric dating?" Tags="|geology|geochemistry|radioactivity|isotopic|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="865" PostTypeId="2" ParentId="436" CreationDate="2014-05-09T12:32:01.270" Score="10" Body="&lt;p&gt;In addition to the theories mentioned by Azzie Rogers, there is another intriguing (but highly tentative) hypothesis: the YD may have been triggered by a large cosmic impact event. The results of a major study of impact-derived spherules at the time of the YD were recently published by Wittke et al. (2013). I should reiterate, though, that this is not currently a very well-supported hypothesis: the paper makes a fairly convincing case for the occurrence of some kind of impact, but mentions the possible climatic effect mainly as an avenue for future study:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The YD impact at 12.8 ka is coincidental with major&#xA;  environmental events, including abrupt cooling at the YD onset,&#xA;  major extinction of some end-Pleistocene megafauna, disappearance&#xA;  of Clovis cultural traditions, widespread biomass&#xA;  burning, and often, the deposition of dark, carbon-rich sediments&#xA;  (black mat). It is reasonable to hypothesize a relationship between&#xA;  these events and the YDB impact, although much work&#xA;  remains to understand the causal mechanisms.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, definitely not a frontrunner for the YD trigger as yet, but one to keep an eye on if further evidence accumulates. The paper is open access, and makes for an interesting read.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Wittke, J. H., Weaver, J. C., Bunch, T. E., Kennett, J. P., Kennett, D. J., Moore, A. M., ... &amp;amp; Firestone, R. B. (2013). Evidence for deposition of 10 million tonnes of impact spherules across four continents 12,800 y ago. &lt;em&gt;Proceedings of the National Academy of Sciences&lt;/em&gt;, 110(23), E2088-E2097. DOI: &lt;a href=&quot;http://dx.doi.org/10.1073/pnas.1301760110&quot; rel=&quot;nofollow&quot;&gt;10.1073/pnas.1301760110&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="94" LastEditorUserId="115" LastEditDate="2014-12-02T17:08:18.597" LastActivityDate="2014-12-02T17:08:18.597" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="866" PostTypeId="2" ParentId="864" CreationDate="2014-05-09T15:10:19.883" Score="10" Body="&lt;p&gt;&quot;Doctor! It hurts when I do this! «bonk»&quot; &quot;So don't do that then!&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One way around the issue of an unknown initial distribution of isotopes is to not do that. One of the most reliable mechanisms for dating the Earth is uranium-lead dating of zircons. Uranium can take the place of zirconium in the zircon crystal because of the chemical similarity of uranium is and zirconium. Lead on the other hand is very dissimilar chemically from zirconium and uranium. The crystal formation process strongly rejects lead. At the time a zirconium crystal forms it will contain no lead. All the lead in zircons comes from the decay of uranium. Two decay chains lead to lead, with &lt;sup&gt;235&lt;/sup&gt;U eventually decaying to &lt;sup&gt;207&lt;/sup&gt;Pb and &lt;sup&gt;238&lt;/sup&gt;U eventually decaying to &lt;sup&gt;206&lt;/sup&gt;Pb. Those two decay chains provide two independent mechanisms to date the same crystal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another approach is to find that initial distribution of isotopes. This is the approach Claire Patterson used in his estimate for the age of the Earth. See &lt;a href=&quot;http://www.colorado.edu/geolsci/courses/GEOL5700-9/pdf/Fall07/Patterson.pdf&quot;&gt;Claire Patterson, &quot;Age of meteorites and the earth&quot;, Geochim Cosmochim Ac 10 (1956)&lt;/a&gt;. He used a non-radioactive iron meteorites to establish the primordial distribution of isotopes of lead. With this as a baseline, he then used the disequilibrium ratios in meteorites to find the age of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regard to varying &lt;sup&gt;234&lt;/sup&gt;U/&lt;sup&gt;238&lt;/sup&gt;U ratios, that's a red herring used by some who don't like the results of radioactive dating in a failed attempt to throw suspicion at those dates. The 256 thousand year half life of &lt;sup&gt;234&lt;/sup&gt;U means that there is no primordial &lt;sup&gt;234&lt;/sup&gt;U on the Earth. All of the &lt;sup&gt;234&lt;/sup&gt;U we see now came from the decay of &lt;sup&gt;238&lt;/sup&gt;U, via &lt;sup&gt;238&lt;/sup&gt;U→&lt;sup&gt;234&lt;/sup&gt;Th→&lt;sup&gt;234&lt;/sup&gt;Pa→&lt;sup&gt;234&lt;/sup&gt;U. Those decays weaken rock at the site of the decays. When the rock weathers and is exposed to water, that weakened rock around a &lt;sup&gt;234&lt;/sup&gt;U atom means that &lt;sup&gt;234&lt;/sup&gt;U is preferentially leached from the rock.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2014-05-09T15:25:32.143" LastActivityDate="2014-05-09T15:25:32.143" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="867" PostTypeId="1" AcceptedAnswerId="2247" CreationDate="2014-05-09T16:54:34.613" Score="10" ViewCount="200" Body="&lt;p&gt;I recently read of a company in Canada using &lt;a href=&quot;http://www.nanaimobulletin.com/news/255397371.html&quot;&gt;robotic technology&lt;/a&gt; to &lt;a href=&quot;http://www.pavilionlake.com/&quot;&gt;study freshwater microbialites&lt;/a&gt;. Their claim is that greater understanding of terrestrial microbialites could help in the search for extraterrestrial microbialite fossils (if they exist) on Mars.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a rover encountered a microbialite fossil on Mars, how would it identify the rock as being a fossil?&lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-07-10T06:30:51.620" Title="How would a Mars rover identify a microbialite fossil?" Tags="|paleontology|fossils|astrobiology|planetology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="869" PostTypeId="2" ParentId="784" CreationDate="2014-05-09T19:35:23.880" Score="6" Body="&lt;p&gt;I would suggest Bense (Hydrologische Karakterisering van Breukzones in Zuid-Oost Nederland), as a starting point. It provides a clear view of a few methods used in the past and an indication of the level of detail needed for the analysis, possibly helping you narrow down your search to a suitable method. Mostly Dutch (not a problem, judging by your name), but few international sources too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have attempted to ascertain something similar in a spatial model (MODFLOW) recently. From experience, I can tell you that the placement of measurement locations is vital, especially when estimating fault resistances. In my case, the available observations offered no evidence supporting the presence of a fault, even though upward seepage and indicator species were widely observed. &lt;/p&gt;&#xA;" OwnerUserId="446" LastActivityDate="2014-05-09T19:35:23.880" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="870" PostTypeId="2" ParentId="609" CreationDate="2014-05-09T20:00:53.340" Score="6" Body="&lt;p&gt;As your question involves environmental law, the correct answer to this question will be based on whichever country or agency would be in charge of providing a permit; as you already noted, commercial considerations will probably end up with doing the minimum requirement. Delving into local law or contacting the appropriate agency will probably provide you with the necessary information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Afterwards, I'd suggest you look at available historical data first: you may not necessarily be required to do a lengthy survey in order to get the answers on your reference situation, first. The data may already be available, and require you to run scenario's for possible effects of extraction.&lt;/p&gt;&#xA;" OwnerUserId="446" LastActivityDate="2014-05-09T20:00:53.340" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="871" PostTypeId="2" ParentId="860" CreationDate="2014-05-09T20:27:08.030" Score="10" Body="&lt;p&gt;Nuclear wastes should be stored in containers designed to contain and isolate radioactive material from the environment. One possibility for the storage of these containers would then be to place them in a repository located in a tectonically stable, dry, geological formation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as lithological characteristics are concerned, it would be best to locate the container repository in rock having mechanical and chemical properties that would limit transport properties and slow or contain the spread of material in the event of a container failure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Advantageous properties include:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) low permeability and few joints and fractures&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) low strength, so that plastic deformation of the rock would tend to reduced stress and close fractures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) mineralogy-fluid chemistry that tends to bind and immobilize radionuclides.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Volcanic tuffs (zeolite-rich), salt deposits, and clay deposits would be examples of lithology having some (but not necessarily all) these characteristics. Granites and columnar jointed basalts may be examples of less advantageous lithology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As @david valentine said, the lithology would be only one of many factors that need to be considered.  &lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-05-09T20:27:08.030" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="872" PostTypeId="2" ParentId="586" CreationDate="2014-05-09T23:30:56.450" Score="6" Body="&lt;p&gt;These are visco-elastic oscillations that cause virtually no permanent deformation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Following the Tohoku 2011 earthquake, this gravimeter in Metsähovi, Finland, measured a &lt;a href=&quot;http://shakingearth.blogspot.com/2011/04/tohoku-quake-and-free-oscillations.html&quot;&gt;radial oscillation mode amplitude of 0.06 mm&lt;/a&gt;. The Earth's radius is 6371 km. So the resulting strains would be extremely small.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All but the lowest radial mode decays after a few days because the energy of the oscillations gets converted to heat by dissipative processes.&lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-05-09T23:30:56.450" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="873" PostTypeId="1" CreationDate="2014-05-10T15:04:51.613" Score="8" ViewCount="670" Body="&lt;p&gt;E.g. the gases listed at &lt;a href=&quot;http://www.ipcc.ch/publications_and_data/ar4/wg1/en/tssts-2-5.html&quot;&gt;http://www.ipcc.ch/publications_and_data/ar4/wg1/en/tssts-2-5.html&lt;/a&gt; . Do they calculate them analytically or theoretically?&lt;/p&gt;&#xA;" OwnerUserId="10" LastActivityDate="2014-06-30T02:22:25.310" Title="How is the radiative efficiency of a given gas (like a given CFC) analytically calculated?" Tags="|atmosphere|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="874" PostTypeId="1" AcceptedAnswerId="919" CreationDate="2014-05-10T19:52:16.843" Score="23" ViewCount="2743" Body="&lt;p&gt;Venus appears to be the closest to Earth in mass, density, size, etc. - though they clearly have different atmospheres.  Why do Earth and Venus have different atmospheres?&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="32" LastEditDate="2014-05-10T21:30:07.843" LastActivityDate="2016-05-27T06:22:52.943" Title="Why do Earth and Venus have different atmospheres?" Tags="|atmosphere|planetary-science|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="875" PostTypeId="1" AcceptedAnswerId="876" CreationDate="2014-05-10T20:40:19.640" Score="44" ViewCount="108124" Body="&lt;p&gt;The &lt;a href=&quot;http://earthquake.usgs.gov/earthquakes/world/10_largest_world.php&quot;&gt;largest earthquake since 1900&lt;/a&gt; according to the United States Geological Survey (&lt;a href=&quot;http://en.wikipedia.org/wiki/United_States_Geological_Survey&quot;&gt;USGS&lt;/a&gt;) was Richter-&lt;a href=&quot;http://en.wikipedia.org/wiki/1960_Valdivia_earthquake&quot;&gt;9.5 magnitude quake in Chile in 1960&lt;/a&gt;. Are magnitude 10 earthquakes possible? If so, what is the most likely frequency of such earthquakes, and where are they the most likely to occur? &lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorDisplayName="user12525" LastEditDate="2019-04-15T14:51:12.530" LastActivityDate="2019-04-15T14:51:12.530" Title="Are Richter-magnitude 10 earthquakes possible?" Tags="|geology|geophysics|earthquakes|seismology|" AnswerCount="6" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="876" PostTypeId="2" ParentId="875" CreationDate="2014-05-10T21:22:01.093" Score="35" Body="&lt;p&gt;Magnitude 10 earthquakes are indeed possible, but very very unlikely. You see the frequency of an Earthquake is given by the &lt;a href=&quot;http://en.wikipedia.org/wiki/Gutenberg%E2%80%93Richter_law&quot; rel=&quot;noreferrer&quot;&gt;Gutenberg-Richter law&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$N = 10^{a-bM}$$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $N$ is the number of earthquakes $\ge M (magnitude)$ and $a,b$ are constants. As you can see, the greater $M$ is, the less $N$ is. $a,b$ are generally solved for statistically, through observational data and regression. But on face value, you can easily see that large magnitude earthquakes become less and less frequent on the exponential level. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as where a magnitude 10 earthquake could occur ? My guess is a subduction zone, as that is where the highest magnitude earthquakes tend to be. Which subduction zone? Anyone's guess is as good as mine, Chile or Tonga, though it is also important to note that earthquake magnitude is often related to fault size: I do not think there is a fault long/large enough to generate a $ M \ge 10.0 $ earthquake on Earth currently. &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="5320" LastEditDate="2017-01-16T21:45:09.313" LastActivityDate="2017-01-16T21:45:09.313" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="877" PostTypeId="1" CreationDate="2014-05-10T22:58:22.097" Score="13" ViewCount="717" Body="&lt;p&gt;I am interested in obtaining ocean wave data (preferably from actual measurements), such as wave height, period, and direction, in the Southeast Asian region. Where can I obtain them?&lt;/p&gt;&#xA;" OwnerUserId="426" LastEditorUserId="192" LastEditDate="2014-12-19T14:25:54.177" LastActivityDate="2014-12-19T14:25:54.177" Title="Where can I obtain ocean wave data of the Southeast Asian region?" Tags="|oceanography|measurements|waves|open-data|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="878" PostTypeId="1" AcceptedAnswerId="910" CreationDate="2014-05-11T03:14:19.903" Score="32" ViewCount="3022" Body="&lt;p&gt;After the Tohoku and East Coast quakes, I skimmed over several books discussing the validity of earthquake prediction as a discipline, yet found no significant breakthroughs. What should change in our methods and models to enable timely forecasts to reduce casualties?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To be clearer, I am not interested in general assessment of seismic hazards (i.e. magnitude distribution for the next 25-50 years), but rather in short-term forecasts precise enough to order evacuation. I am aware that evacuation is a contentious issue...&lt;/p&gt;&#xA;" OwnerUserId="269" LastEditorUserId="6129" LastEditDate="2020-05-05T16:07:22.460" LastActivityDate="2020-05-05T16:07:22.460" Title="Is earthquake prediction possible?" Tags="|geophysics|earthquakes|seismology|predictability|" AnswerCount="8" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="879" PostTypeId="2" ParentId="875" CreationDate="2014-05-11T03:26:59.063" Score="21" Body="&lt;p&gt;Perhaps this is not what you had in mind, but it seems to be &lt;a href=&quot;http://www.researchgate.net/publication/225799644_Numerical_Modeling_of_the_Largest_Terrestrial_Meteorite_Craters&quot;&gt;generally agreed&lt;/a&gt; that the &lt;a href=&quot;http://newswatch.nationalgeographic.com/2010/03/04/asteroid_terminated_dinosaur_era_in_days/&quot;&gt;Chicxulub asteroid impact&lt;/a&gt; generated earthquakes in excess of magnitude 10.&lt;/p&gt;&#xA;" OwnerUserId="455" LastEditorUserId="455" LastEditDate="2014-05-12T11:39:08.023" LastActivityDate="2014-05-12T11:39:08.023" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="881" PostTypeId="2" ParentId="875" CreationDate="2014-05-11T09:55:42.073" Score="37" Body="&lt;p&gt;Adding a little bit of practical data to the above answer about the Gutenberg-Richter relationship, here is a plot of the per-year cumulative probability of earthquakes in a particular province in Japan, based on observed frequencies over many hundreds of years:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/4Kakk.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://topo.earth.chiba-u.jp/afr/backnumber/no24/24%E5%8F%B702kumamoto.pdf&quot;&gt;http://topo.earth.chiba-u.jp/afr/backnumber/no24/24%E5%8F%B702kumamoto.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The relationship is plausibly log-linear (in accordance with G-R); if you accept that the relationship will hold up to higher magnitudes, you would estimate the probability of a M10 event in this location at once every 30,000 years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get an estimate for &quot;anywhere in the world&quot; you would need the cumulative data for all. A good place to start is the USGS website - they have a &lt;a href=&quot;http://earthquake.usgs.gov/earthquakes/eqarchives/year/eqstats.php&quot;&gt;handy table with data since 1900&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Taking these data and plotting them on a log-linear graph, then extrapolating a linear fit, gives the following chart:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/xMhgm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is rather scary because it suggests that there is about a 1:100 chance of a M10 earthquake anywhere in the world, in any given year. Note that I plotted the data for &lt;code&gt;magnitude x to x.9&lt;/code&gt; at the location of &lt;code&gt;x&lt;/code&gt; - which tends to underestimate things a little bit. Note also that at the extreme end of very large earthquakes (8 and above), the data looks like it might be deviating from the straight line - but there are not enough data points to draw any firm conclusions about the shape.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are several other caveats. First - the assumption that the model can be extrapolated can be challenged: a particular fault may not be constructed in such a way as to store the energy required for an M10 event, as it will always release the energy before it gets there (and there may be a &quot;stress shadow&quot; effect, which says that after a big earthquake, the chance of another big one is temporarily reduced because stresses have been relieved; this is why this model can only be used &quot;over a long period&quot;, and does not accurately reflect the risk of earthquake in the next five years).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Still - one percent.&lt;/p&gt;&#xA;" OwnerUserId="453" LastActivityDate="2014-05-11T09:55:42.073" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="882" PostTypeId="2" ParentId="875" CreationDate="2014-05-11T14:07:16.167" Score="35" Body="&lt;h2&gt;Are magnitude 10 earthquakes possible?&lt;/h2&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The idea of a “Mega-Quake” – an earthquake of magnitude 10 or larger –&#xA;  while theoretically possible—is very highly unlikely. Earthquake&#xA;  magnitude is based in part on the length of faults -- the longer the&#xA;  fault, the larger the earthquake. The simple truth is that there are&#xA;  no known faults capable of generating a magnitude 10 or larger&#xA;  “mega-quake.” (&lt;a href=&quot;http://earthquake.usgs.gov/learn/topics/megaquakes.php&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;h2&gt;Where are magnitude 10 earthquakes the most likely to occur?&lt;/h2&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Nine out of the ten largest earthquakes to occur in the last century&#xA;  were subduction zone events. This includes the 1960 Great Chilean&#xA;  Earthquake, which at M 9.5 was the largest earthquake ever recorded,&#xA;  the 2004 Indian Ocean earthquake and tsunami, and the 2011 Tōhoku&#xA;  earthquake and tsunami. (&lt;a href=&quot;http://en.wikipedia.org/wiki/Subduction#Earthquakes_and_tsunamis&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Map of Subduction Zones Worldwide&lt;/strong&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/a0Bex.gif&quot; alt=&quot;Map of Subduction Zones Worldwide&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;What is the most likely frequency of magnitude 10 earthquakes?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;If they were possible, given there are none recorded in written history, there's no absolution way to say without a great deal of uncertainty.  &lt;strong&gt;The historical data is misleading.&lt;/strong&gt; For an explanation, see: &lt;strong&gt;(1)&lt;/strong&gt; &quot;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/845/does-volcanic-activity-fluctuate/846#846&quot;&gt;This is probably an observational effect that is quite common in the Earth Sciences.&lt;/a&gt;&quot; &lt;strong&gt;(2)&lt;/strong&gt; &quot;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/665/are-there-more-earthquakes-near-the-equator-or-poles#comment1212_665&quot;&gt;Note that prior to 1903, there are no earthquakes mapped as located along the mid-ocean ridge.&lt;/a&gt;&quot;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;How big are magnitude 10 earthquakes?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Very big. To get some idea, this pie chart shows how the total &lt;a href=&quot;http://en.wikipedia.org/wiki/seismic_moment&quot; rel=&quot;noreferrer&quot;&gt;seismic moment&lt;/a&gt; released by earthquakes over the period 1906-2005 was distributed, with the largest individual earthquakes (left side) and groups of earthquakes (right side). The thin sliver of the 1906 San Francisco Earthquake is also depicted for comparison purposes. M&lt;sub&gt;w&lt;/sub&gt; designates an earthquake's magnitude on the &lt;a href=&quot;http://en.wikipedia.org/wiki/moment_magnitude_scale&quot; rel=&quot;noreferrer&quot;&gt;moment magnitude scale&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/agW4r.jpg&quot; alt=&quot;Graph of largest earthquakes 1906-2005&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;CAPTION:&lt;/strong&gt; Global seismic release from 1906 to 2005, the graph shows that almost 25% of the world earthquake energy in a century was concentrated in the Great Chilean Earthquake alone.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-05-11T15:01:20.543" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="883" PostTypeId="2" ParentId="665" CreationDate="2014-05-11T14:15:05.270" Score="2" Body="&lt;p&gt;Here is one way to think about this problem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earthquakes that happen above latitude 45 are closer to the pole; the ones between +-45 degrees are closer to the equator.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the earth is a sphere, the total area of the earth's surface between +-45 degrees is about 70% of the total area (1/sqrt(2) to be precise). In other words, there is &quot;a lot more earth near the equator than near the poles&quot; - more than twice as much. This means that if earthquakes occurred with equal probability anywhere in the world, you would expect the answer to be a resounding &quot;yes&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you take into account the maps you are showing, I think that the answer is still yes - even without doing a detailed calculation.&lt;/p&gt;&#xA;" OwnerUserId="453" LastActivityDate="2014-05-11T14:15:05.270" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="884" PostTypeId="1" AcceptedAnswerId="886" CreationDate="2014-05-11T16:41:49.397" Score="9" ViewCount="511" Body="&lt;p&gt;&lt;strong&gt;According to the graph below, Arctic sea ice volume has been decreasing from 1979-2012:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/0vKC4.png&quot; alt=&quot;Arctic Sea Ice Volume, 1979-2012&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Though this &lt;a href=&quot;http://www.esa.int/Our_Activities/Observing_the_Earth/CryoSat/Arctic_sea_ice_up_from_record_low&quot; rel=&quot;noreferrer&quot;&gt;graph from the ESA’s CryoSat satellite show that the volume of Arctic sea ice increased 50% from 2012 to 2013&lt;/a&gt;:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/EFhMM.gif&quot; alt=&quot;animation showing October Arctic sea ice volume up 50% 2012 to 2013&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is the explanation for the difference accounts of Arctic sea ice volume trends?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="94" LastEditDate="2014-05-13T10:32:55.527" LastActivityDate="2014-05-13T10:32:55.527" Title="Is the Arctic sea ice volume increasing?" Tags="|sea-ice|cryosphere|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="885" PostTypeId="2" ParentId="884" CreationDate="2014-05-11T17:33:56.407" Score="5" Body="&lt;p&gt;Few things to notice are that while the Arctic Sea volume increased 50%, the volume increase was marginal compared with the volume of sea ice in 1979. Next, if you review the graph below, one year spikes are not that unusual, though if there was another 50% the volume increase from 2013 to 2014, it would be of note, given the rarity of significant year over year increases in Arctic Sea volume.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/i3Xwc.png&quot; alt=&quot;Arctic Sea volume, 1979-2013&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastActivityDate="2014-05-11T17:33:56.407" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="886" PostTypeId="2" ParentId="884" CreationDate="2014-05-11T17:40:30.943" Score="14" Body="&lt;p&gt;This question has already been answered on Skeptics.SE:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://skeptics.stackexchange.com/questions/17695/did-the-arctic-ice-sheet-grow-by-60-from-2012-to-2013&quot;&gt;Did the Arctic Ice Sheet grow by 60% from 2012 to 2013?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The short answer is that those two graphs are consistent with each other. The first shows a 33 year trend of declining Arctic sea ice (summer minimum, I think), whereas the second highlights inter-annual variation in Arctic sea ice over the last four years.  We don't expect long-term trends to be strictly monotonic increases or decreases, so both positive or negative year-on-year differences, such as those between 2012 and 2013, can be consistent with the trend.&lt;/p&gt;&#xA;" OwnerUserId="106" LastEditorUserId="-1" LastEditDate="2017-04-13T12:46:45.430" LastActivityDate="2014-05-11T17:40:30.943" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="887" PostTypeId="2" ParentId="877" CreationDate="2014-05-11T17:43:54.740" Score="9" Body="&lt;p&gt;The only open and ongoing data source for in-situ ocean wave measurements I am aware of is the &lt;a href=&quot;http://www.ndbc.noaa.gov/&quot;&gt;National Data Buoy Center&lt;/a&gt;. Though NDBC manages data service from plenty of moored buoys in the Gulf of Mexico and the Atlantic and Pacific coasts of North America, unfortunately there isn't much in your region of interest. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only buoys I have found that are somewhat near the Southeast Asian region are 2 buoys on the east and west side of Guam, and one right by Northern Mariana Islands:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.ndbc.noaa.gov/station_page.php?station=52200&quot;&gt;http://www.ndbc.noaa.gov/station_page.php?station=52200&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.ndbc.noaa.gov/station_page.php?station=52202&quot;&gt;http://www.ndbc.noaa.gov/station_page.php?station=52202&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.ndbc.noaa.gov/station_page.php?station=52211&quot;&gt;http://www.ndbc.noaa.gov/station_page.php?station=52211&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;These buoys provide directional energy spectrum data, as well as integrated quantities like significant wave height and mean and dominant wave period. I've written a Python library that lets you parse NDBC server and access data from buoys from command line or your Python programs. Once I tidy it up and make it public, I will update this answer so that other people can use it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your other option, as suggested by @DeerHunter, is to use altimetry data from polar-orbiting satellites. Although these are sparse and provide only wave heights (no period or direction information), they may be your only bet depending on the region of interest.&lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2014-05-11T17:58:10.260" LastActivityDate="2014-05-11T17:58:10.260" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="888" PostTypeId="1" AcceptedAnswerId="1072" CreationDate="2014-05-11T18:45:26.467" Score="11" ViewCount="517" Body="&lt;p&gt;So recently, scientists managed to &lt;a href=&quot;http://www.rsc.org/chemistryworld/2014/05/solar-jet-fuel-made-out-thin-air&quot; rel=&quot;nofollow&quot;&gt;produce fuel basically out of thin air&lt;/a&gt; (water, air and sunlight).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And in a discussion I had with a friend, the question came up, what would happen if you took that idea too far?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Say you could build an air-to-fuel plant large and efficient enough to take CO&lt;sub&gt;2&lt;/sub&gt; out of the atmosphere faster than all the things we currently do to increase CO&lt;sub&gt;2&lt;/sub&gt; levels add it in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would happen? First of all, how far could you realistically even take this: Would it be possible with the used process to go all the way down to 0 atmospheric CO&lt;sub&gt;2&lt;/sub&gt; (or at least approach this arbitrarily closely)? And what effects would this have on the environment?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I immediately had three ideas that could happen but I wonder how realistic those would be:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Average temperatures would drop (inverse Greenhouse effect) (but how far?)&lt;/li&gt;&#xA;&lt;li&gt;Plants would eventually be unable to produce sugar through photosynthesis and die off&lt;/li&gt;&#xA;&lt;li&gt;Instead of acidifying, oceans would become increasingly alkaline. Lime might drop out of the oceans rapidly which could, perhaps, have cancer-like effects on coral reefs and anything that heavily depends on lime.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;And besides those, are there any other obvious notable effects?&lt;/p&gt;&#xA;" OwnerUserId="463" LastEditorUserId="595" LastEditDate="2014-11-18T09:05:17.893" LastActivityDate="2015-08-31T23:15:39.333" Title="What would happen if we could revert $\mathrm{CO}_2$ production but took it too far?" Tags="|climate|climate-change|hypothetical|co2|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="889" PostTypeId="1" AcceptedAnswerId="903" CreationDate="2014-05-11T19:11:20.343" Score="9" ViewCount="176" Body="&lt;p&gt;There are a few theories as to the causes of glaciation.&lt;br&gt;&#xA;There's the Milankovitch Theory, which says that there are cyclical changes in Earth's orbit and in the tilt of Earth's axis that occur over thousands of years and cause climate changes.&lt;br&gt;&#xA;Some scientists believe that the solar energy made by the sun is not constant and that may be why it gets so cold that glaciers form sometimes.&lt;br&gt;&#xA;Others say that when volcanic dust blocks the sun's rays, making it harder for solar radiation to reach Earth's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While the first one can't exactly be proven, it can't be disproven either, and is the theory most go with. So why or why don't the second and third theories work/what makes them less popular?&lt;/p&gt;&#xA;" OwnerDisplayName="user464" LastEditorUserId="94" LastEditDate="2014-05-12T10:52:12.580" LastActivityDate="2014-05-12T10:52:12.580" Title="Why are some theories as to the cause of glacation less popular among the scientific community?" Tags="|paleoclimatology|ice-age|glaciology|milankovitch-cycles|glaciation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="890" PostTypeId="1" CreationDate="2014-05-11T20:18:49.423" Score="11" ViewCount="2831" Body="&lt;p&gt;The National Climatic Data Center (NCDC) data shows the &lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/usclimate/tmp.state.19712000.climo&quot; rel=&quot;noreferrer&quot;&gt;mean temperature from 1971-2000 for Montana was 5.97°C (42.74°F) and Wyoming's was 5.54°C (41.98°F)&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Montana is at a higher latitude, so this is surprising.&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="124" LastEditDate="2014-10-30T09:27:59.673" LastActivityDate="2014-10-30T09:27:59.673" Title="Why is Montana warmer than Wyoming?" Tags="|meteorology|climate|temperature|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="891" PostTypeId="1" AcceptedAnswerId="2273" CreationDate="2014-05-11T20:26:30.197" Score="4" ViewCount="513" Body="&lt;p&gt;&quot;&lt;a href=&quot;http://lukemweather.blogspot.com/2011/01/jet-streak-dynamics-i-four-quadrant.html&quot; rel=&quot;nofollow&quot;&gt;Jet Streak Dynamics I: The four-quadrant model&lt;/a&gt;&quot; - explains their effects on frontogenesis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But how are they formed to begin with?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="64" LastEditDate="2014-05-12T01:16:50.717" LastActivityDate="2014-07-17T20:52:14.663" Title="How are jet streaks formed?" Tags="|meteorology|weather|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="892" PostTypeId="1" CreationDate="2014-05-11T20:28:20.427" Score="5" ViewCount="42" Body="&lt;p&gt;Do they move at the group velocity of Rossby Waves? Or do they move at the phase velocity of Rossby Waves? Or some other speed?&lt;/p&gt;&#xA;" OwnerUserId="10" LastActivityDate="2014-05-11T20:28:20.427" Title="What determines the eastward speed that mid-latitude high pressure/low pressure systems move at?" Tags="|weather|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="893" PostTypeId="1" CreationDate="2014-05-11T20:35:34.800" Score="8" ViewCount="219" Body="&lt;p&gt;It's often said that the ECMWF model is more accurate than the GFS. But what are the reasons why? Also, how does the NAM compare with these two and other forecasting models?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="64" LastEditDate="2014-08-10T03:40:33.843" LastActivityDate="2014-08-10T03:40:33.843" Title="What determines the differences in results between various weather models?" Tags="|meteorology|weather|models|nwp|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="894" PostTypeId="1" CreationDate="2014-05-11T20:50:35.200" Score="5" ViewCount="126" Body="&lt;p&gt;Warm fronts are associated with an increase in temperature and precipitation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But are they often associated with record high daily maximum temperatures, given that they often result in an increase in cloudiness? Or are they more often associated with record high daily minimum temperatures?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="64" LastEditDate="2014-05-21T13:29:54.787" LastActivityDate="2014-06-06T19:27:49.543" Title="How common is it for warm fronts to be responsible for record high temperatures?" Tags="|meteorology|weather|temperature|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="895" PostTypeId="1" CreationDate="2014-05-11T20:54:23.527" Score="6" ViewCount="103" Body="&lt;p&gt;There's a lot of downwelling in the region. Does this increase sedimentation rates?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="111" LastEditDate="2015-02-25T03:58:14.397" LastActivityDate="2015-02-25T03:58:14.397" Title="How does the meridional overturning circulation affect sedimentation rates in the North Atlantic?" Tags="|ocean|sedimentology|thermohaline-circulation|atlantic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="896" PostTypeId="1" AcceptedAnswerId="997" CreationDate="2014-05-11T21:00:16.277" Score="8" ViewCount="109" Body="&lt;p&gt;Does it result in an increased exchange of surface heat and deepwater heat, which, in turn, help increase the amount of CO&lt;sub&gt;2&lt;/sub&gt; and heat that the deep oceans absorb?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Related-On-Wikipedia:&lt;/strong&gt; &lt;a href=&quot;http://en.wikipedia.org/wiki/Meridional_overturning_circulation&quot; rel=&quot;noreferrer&quot;&gt;Meridional overturning circulation (Thermohaline circulation)&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="87" LastEditDate="2014-05-12T11:16:59.483" LastActivityDate="2014-12-23T03:14:24.377" Title="Does the meridional overturning circulation slow down the temperature increase from global warming?" Tags="|ocean|thermohaline-circulation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="898" PostTypeId="1" AcceptedAnswerId="956" CreationDate="2014-05-12T00:16:57.040" Score="9" ViewCount="104" Body="&lt;p&gt;A shutdown in the circulation was associated with the &lt;a href=&quot;http://en.wikipedia.org/wiki/Younger_Dryas&quot; rel=&quot;nofollow&quot;&gt;Younger Dryas&lt;/a&gt; stadial, also referred to as the Big Freeze, so I'm curious how much warmer Western Europe is due to the MOC, and how much heat (in Joules) the MOC actually releases into the region.&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="64" LastEditDate="2014-05-21T03:02:31.567" LastActivityDate="2014-05-21T03:02:31.567" Title="How much is Iceland/Norway/Western Europe warmed up by the Meriodional Overturning Circulation?" Tags="|climate|oceanography|ocean-currents|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="899" PostTypeId="1" AcceptedAnswerId="902" CreationDate="2014-05-12T00:23:25.710" Score="7" ViewCount="179" Body="&lt;p&gt;Did El Niño extend all the way to the West Coast of Africa? Did the meridional overturning circulation exist back then? Was there another overturning circulation that existed?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="111" LastEditDate="2014-12-21T21:52:54.347" LastActivityDate="2014-12-21T21:52:54.347" Title="How was the atmospheric/oceanic circulation different prior to the formation of the Isthmus of Panama?" Tags="|ocean|thermohaline-circulation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="900" PostTypeId="1" CreationDate="2014-05-12T00:24:57.563" Score="7" ViewCount="1162" Body="&lt;p&gt;&lt;a href=&quot;http://www.cesm.ucar.edu/models/atm-cam/docs/description/node31.html&quot;&gt;Evaluation of the Ocean Q Flux&lt;/a&gt; is an example of qflux used in the CESM model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is it important?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="111" LastEditDate="2014-05-12T15:35:14.777" LastActivityDate="2014-05-15T10:34:50.727" Title="What is &quot;qflux&quot; and why is it important for climate models?" Tags="|ocean|climate|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="901" PostTypeId="1" CreationDate="2014-05-12T02:27:27.420" Score="7" ViewCount="153" Body="&lt;p&gt;Why does it take the very weird loop that it takes in the Pacific Ocean? And also in the Indian ocean too? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Li907.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="111" LastEditDate="2014-05-12T15:35:18.233" LastActivityDate="2024-02-11T04:24:14.650" Title="Why does the meridional overturning circulation take the convoluted path that it takes?" Tags="|ocean|thermohaline-circulation|ocean-currents|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="902" PostTypeId="2" ParentId="899" CreationDate="2014-05-12T06:57:02.737" Score="7" Body="&lt;p&gt;Concerning the thermohaline circulation: the defining part of it, I think, is the formation of bottom water in the polar regions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The formation of Antarctic Bottom Water (AABW) in the Southern Ocean is strongly linked to the presence of the Antarctic Circumpolar current (ACC). The ACC was possible only after the opening of the Tasmanian Gateway and the Drake Passage (between Antarctica &amp;amp; South America) which both happened in the Late Eocene / earliest Oligocene. The ACC is thought to have been the deep, strong current it is today since the Late Oligocene at the very latest (&lt;strong&gt;Lyle et al. 2008&lt;/strong&gt;), so the AABW is also thought to have existed since the Oligocene.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However as far as the North Atlantic Deep Water (NADW) formation is concerned: it is linked indeed in part to the Gulf Stream and the Northern Hemisphere glaciation. While the latter only occurred ca. 3.6Ma (e. g. &lt;strong&gt;Muddelsee &amp;amp; Raymo 2005&lt;/strong&gt;), the Gulf Stream is a direct consequence of the closure of the isthmus of Panama: the shallowing (and therefore closure to deep current) of the Panama Seaway is thought to have happenned at ca. 4.6Ma (&lt;strong&gt;Haug &amp;amp; Tiedemann 1998&lt;/strong&gt;) with a complete closure at 2.6Ma (&lt;strong&gt;Lunt et al. 2008&lt;/strong&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So it is rather safe to say that the thermohaline circulation as we know it today settled probably around 3.6Ma (therefore mid-Pliocene).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Back in the Eocene (55 to 33Ma), the formation of bottom water is thought to have occurred in middle to low latitude (e. g. &lt;strong&gt;Kennett &amp;amp; Stott 1990&lt;/strong&gt;) leading to a very completely different kind of global circulation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The impact on the ENSO (if it existed at the time) is, as far as I know, unknown but since South America was still here to limit it eastward I don't think it ever reached Africa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;References:&lt;br&gt;&#xA;Haug, G. H. &amp;amp; R. Tiedemann. 1998. &lt;a href=&quot;http://dx.doi.org/10.1038/31447&quot; rel=&quot;nofollow&quot;&gt;Effect of the formation of the Isthmus of Panama on Atlantic Ocean thermohaline circulation.&lt;/a&gt; Nature, 393: 673-676.&lt;br&gt;&#xA;Kennett, J. P. &amp;amp; L. D. Stott. 1990. &lt;a href=&quot;http://dx.doi.org/10.2973/odp.proc.sr.113.188.1990&quot; rel=&quot;nofollow&quot;&gt;Proteus and Proto-oceanus: ancestral Paleogene oceans as revealed from Antarctic stable isotopic results; ODP Leg 113.&lt;/a&gt; In P. F. Barker et al. (Eds), Proceedings of the Ocean Drilling Program, Scientific Results, College Station, TX (Ocean Drilling Program), 113: 865-880.&lt;br&gt;&#xA;Lunt, D. J., P. J. Valdes, A. Haywood &amp;amp; I. C. Rutt. 2008. &lt;a href=&quot;http://dx.doi.org/10.1007/s00382-007-0265-6&quot; rel=&quot;nofollow&quot;&gt;Closure of the Panama Seaway during the Pliocene: implications for climate and Northern Hemisphere glaciation.&lt;/a&gt; Climate Dynamics, 30: 1-18.&lt;br&gt;&#xA;Lyle, M., Gibbs, S., Moore T. C., Rea, D. K., 2007. &lt;a href=&quot;http://dx.doi.org/10.1130/G23806A.1&quot; rel=&quot;nofollow&quot;&gt;Late Oligocene initiation of the Antarctic Circumpolar Current: evidence from the South Pacific.&lt;/a&gt; Geology, 35(8): 691-694.&lt;br&gt;&#xA;Mudelsee, M. &amp;amp; M. E. Raymo. 2005. &lt;a href=&quot;http://dx.doi.org/10.1029/2005PA001153&quot; rel=&quot;nofollow&quot;&gt;Slow dynamics of the Northern Hemisphere glaciation.&lt;/a&gt; Paleoceanography, 20: PA4022.&#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-05-12T15:01:50.537" LastActivityDate="2014-05-12T15:01:50.537" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="903" PostTypeId="2" ParentId="889" CreationDate="2014-05-12T07:05:54.933" Score="6" Body="&lt;p&gt;Your question is framed as if any model of glaciation were only allowed to consider &lt;em&gt;one&lt;/em&gt; of those influences. I think practically any palaeoclimatologist would accept that &lt;a href=&quot;https://en.wikipedia.org/wiki/Orbital_forcing&quot; rel=&quot;nofollow&quot;&gt;astronomical forcing&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_variation&quot; rel=&quot;nofollow&quot;&gt;solar output&lt;/a&gt;, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Volcanic_eruption&quot; rel=&quot;nofollow&quot;&gt;volcanic eruptions&lt;/a&gt; all have effects on glaciation. It's true, however, that on long timescales (tens of kiloyears and up), Milankovitch forcing generally gets more attention than the other two you mention. There are further important drivers of glaciation which you don't mention. Perhaps the most obvious is &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_dioxide_in_the_Earth%27s_atmosphere#Past_variation&quot; rel=&quot;nofollow&quot;&gt;greenhouse gas concentration&lt;/a&gt;: if atmospheric levels of CO&lt;sub&gt;2&lt;/sub&gt;, methane, and other greenhouse gases drop, the Earth cools and glaciation becomes more likely (see e.g. &lt;strong&gt;DeConto and Pollard, 2003&lt;/strong&gt;). Another influence is tectonics and geography, the best-known example perhaps being the theory that Antarctic glaciation was caused by the break-up of &lt;a href=&quot;https://en.wikipedia.org/wiki/Gondwana&quot; rel=&quot;nofollow&quot;&gt;Gondwana&lt;/a&gt;, which left Antarctica thermally isolated (&lt;strong&gt;Kennett, 1977&lt;/strong&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To return to your main question, there's a good reason to consider Milankovitch forcing as a (or the) dominant driver of glaciation on longer timescales: it's simply that glaciation (as deduced from δ&lt;sup&gt;18&lt;/sup&gt;O records) varies in time with the astronomical cycles. &lt;strong&gt;Hays et al. (1976)&lt;/strong&gt; is one of the classic papers on this, and they sum the situation up neatly:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Over the frequency range 10&lt;sup&gt;−4&lt;/sup&gt; to&#xA;  10&lt;sup&gt;−5&lt;/sup&gt; cycle per year, climatic variance of&#xA;  these records is concentrated in three discrete&#xA;  spectral peaks at periods of 23,000,&#xA;  42,000, and approximately 100,000&#xA;  years. These peaks correspond to the&#xA;  dominant periods of the earth's solar orbit,&#xA;  and contain respectively about 10,&#xA;  25, and 50 percent of the climatic variance.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;To put it another way: if you want to discount astronomical forcing and attribute those variations to (say) volcanic aerosols, you need to explain why you have volcanoes going off at precise 42,000-year intervals. This isn't to say that we fully understand how these drivers interact with the climate system yet (the &lt;a href=&quot;https://en.wikipedia.org/wiki/100,000-year_problem&quot; rel=&quot;nofollow&quot;&gt;100,000-year problem&lt;/a&gt; is perhaps the best-known &quot;wrinkle&quot; in the theory), but the fact remains that if your glaciations are dancing to 23, 42, and 100-kiloyear beats, and your solar system happens to be providing beats at precisely those frequencies, there's probably a pretty strong connection there.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;DeConto, R. M., &amp;amp; Pollard, D. (2003). &lt;a href=&quot;http://dx.doi.org/10.1038/nature01290&quot; rel=&quot;nofollow&quot;&gt;Rapid Cenozoic glaciation of Antarctica induced by declining atmospheric CO2&lt;/a&gt;. &lt;em&gt;Nature&lt;/em&gt;, 421(6920), 245-249.&lt;/li&gt;&#xA;&lt;li&gt;Hays, J. D., Imbrie, J., &amp;amp; Shackleton, N. J. (1976). &lt;a href=&quot;http://www.whoi.edu/science/GG/paleoseminar/ps/hays76.ps&quot; rel=&quot;nofollow&quot;&gt;Variations in the Earth's orbit: Pacemaker of the ice ages&lt;/a&gt; (PostScript). &lt;em&gt;Science&lt;/em&gt;, 192(4270), 1121-1132.&lt;/li&gt;&#xA;&lt;li&gt;Kennett, J. P. (1977). &lt;a href=&quot;http://dx.doi.org/10.1029/JC082i027p03843&quot; rel=&quot;nofollow&quot;&gt;Cenozoic evolution of Antarctic glaciation, the circum‐Antarctic Ocean, and their impact on global paleoceanography&lt;/a&gt;. &lt;em&gt;Journal of Geophysical Research&lt;/em&gt;, 82(27), 3843-3860.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="94" LastEditorUserId="269" LastEditDate="2014-05-12T10:08:12.560" LastActivityDate="2014-05-12T10:08:12.560" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="904" PostTypeId="2" ParentId="901" CreationDate="2014-05-12T14:53:53.013" Score="6" Body="&lt;p&gt;The diagram presented in the question is a very simplified version of the meridional overturning circulation. It is overly simplistic and generally creates very large misunderstandings. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good reference to the evolution of the Meridional Overturning Circulation diagrams is the work by &lt;a href=&quot;http://dx.doi.org/10.1016/j.pocean.2008.01.005&quot;&gt;Richardson (2008)&lt;/a&gt;. Just in case you don't have access to Progress in Oceanography, you can click &lt;a href=&quot;https://www.google.com/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=14&amp;amp;ved=0CGkQFjAN&amp;amp;url=https://darchive.mblwhoilibrary.org/handle/1912/2578?show=full&amp;amp;ei=U9FwU8WUHcLfsATk_4HwDQ&amp;amp;usg=AFQjCNEV5LRb-qpREEiNSuqiyzcN9iVzZQ&amp;amp;sig2=sQI7RSkMYKbMIzFnb2NJHw&amp;amp;cad=rja&quot;&gt;here&lt;/a&gt; and see if that works.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The diagram that I find more useful and, while a simplification, still rather realistic is the one by &lt;a href=&quot;http://pong.tamu.edu/~rob/class/410/WHOI-96-08.pdf&quot;&gt;Schmitz (1996)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now let's answer the question about the &quot;weird loop&quot;. We need to realize that, in the diagram presented, the blue arrows represent flow of deep water (denser water, usually colder), while the red arrows represent surface water flow (lighter water, usually warmer). The loops in the Pacific and Indian ocean represent a transition from cold water into warmer water usually through mixing. The exact location of the mixing and upward vertical flow (upwelling) does not occur in the areas represented by the loop in the diagram, but rather in several other locations in the Pacific and Indian Ocean (for instance, upwelling in the California Current System, mixing in the &lt;a href=&quot;http://www.indonesianthroughflow.com/&quot;&gt;Indonesian Throughflow&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-05-12T14:53:53.013" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="905" PostTypeId="2" ParentId="900" CreationDate="2014-05-12T14:59:43.117" Score="9" Body="&lt;p&gt;Q= Ocean heat flux&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Slab Ocean Model is the name when the atmospheric component of CESM is coupled with ocean mixed layer. When CESM is configured in the fully coupled way, there's no need for the Q flux computation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;GCMs coupled with ocean mixed layer (and thus a thermodynamical ocean instead of a dynamical ocean) computes Q flux to account for the exchange of heat with the ocean. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;http://www.cesm.ucar.edu/models/atm-cam/docs/description/node28.html&quot;&gt;http://www.cesm.ucar.edu/models/atm-cam/docs/description/node28.html&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The ocean mixed layer contains an internal heat source $ Q$ (also called a $ Q$ flux), whose values are generally specified by a CAM control run, representing seasonal deep water exchange and horizontal ocean heat transport. For example, using prescribed sea surface temperatures and sea ice distributions, the net surface energy flux over the ocean surface can be evaluated to yield the heat source $ Q$. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="111" LastEditorUserId="476" LastEditDate="2014-05-15T10:34:50.727" LastActivityDate="2014-05-15T10:34:50.727" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="906" PostTypeId="1" AcceptedAnswerId="908" CreationDate="2014-05-10T09:24:19.527" Score="23" ViewCount="911" Body="&lt;p&gt;Weird question, bear with me.&#xA;Most large peninsula on Earth are oriented southwards (and most of the rest northwards), much fewer east or west. Some examples:&#xA;Florida, Californa peninsula, Yucatan, South America, Antarctic peninsula, India, Kamtjatka, Korea, Malaysia, Scandinavia, Italy, Greece, Greenland. Contrary examples would be east Siberia, Kola, Turkey. (Is it just me, or have this question ever been raised before in history?)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this just coincidence, or could conceivably some tectonic, gravitational or rotational forces help cause this phenomena? Maybe because the tectonic ridges in the Atlantic and the Pacific are north-south oriented and stretch almost from pole to pole? And could that in turn be caused by the dynamics of the inner Earth?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Elevation maps of Venus are more fragmented than the continents of Earth. And Mars is half highland half lowland. Neither has plate tectonics like Earth.&lt;/p&gt;&#xA;" OwnerUserId="3033" OwnerDisplayName="LocalFluff" LastEditorUserId="87" LastEditDate="2014-11-20T07:41:22.767" LastActivityDate="2015-07-27T12:40:58.870" Title="Why are most peninsulas oriented north-south?" Tags="|tectonics|geomorphology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="907" PostTypeId="2" ParentId="878" CreationDate="2014-05-12T17:24:59.477" Score="7" Body="&lt;p&gt;Although perfect forecasting of where and when the next earthquake will occur (which is how the public interprets the term 'prediction') is not physically impossible, this requires more information than we have at present. It is possible that in the future we could have enough understanding of earthquake mechanisms, and real-time knowledge of precursors, to actually forecast the next earthquake at least as precisely as we can currently forecast the next major flood or storm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The interests of society are better served by the evaluation and mitigation of seismic hazards rather than by predicting earthquakes.  A precise prediction of an earthquake might actually be less useful than an accurate evaluation of seismic hazards - if the objective is to minimize the loss of life and property.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Questions such as this one can be improved by deciding whether you are asking about seismic risk or the physical mechanisms of earthquakes. If the latter, you need to be more specific about what hypothesis you are asking about.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact, the basic physical mechanism responsible for earthquakes is understood to be &lt;a href=&quot;http://www.youtube.com/watch?v=_YLjIvJXhpg&quot;&gt;elastic rebound&lt;/a&gt; . It's really the details of that mechanism that are still the subject of study.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are asking whether it will be possible, in the future, to forecast earthquakes sufficiently well to justify the evacuation of a major city, I would say yes. However, that is also going to depend upon municipal &lt;a href=&quot;http://en.wikipedia.org/wiki/Emergency_evacuation&quot;&gt;emergency evacuation capacity&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The prediction of an earthquake has consequences in and of itself, and seismologists have been: &lt;a href=&quot;http://seismo.berkeley.edu/blog/seismoblog.php/2012/10/23/sent-to-jail-for-not&quot;&gt;Sent to Jail for Being Too Flippant&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I had to guess where the future breakthroughs in seismology leading to better earthquake forecasting will come from - I would guess real-time &lt;a href=&quot;http://www-radar.jpl.nasa.gov/sect323/InSar4crust/&quot;&gt;remote sensing of crustal deformation&lt;/a&gt; from space platforms. This will produce large amounts of data about fault-zones, in real-time and computer-accessible format, that can be interpreted in terms of our present understanding of earthquake physics. &lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorUserId="178" LastEditDate="2014-05-13T17:02:45.453" LastActivityDate="2014-05-13T17:02:45.453" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="908" PostTypeId="2" ParentId="906" CreationDate="2014-05-12T17:52:03.247" Score="18" Body="&lt;p&gt;Starting from the bottom of your question I would not compare planets with plate tectonics with planets that don't have this process. During rifting of a tectonic plate a triple junction will be the most favourable way of faulting the crust. After that two arms of the rift are favoured and the third one becomes a failed rift (aulacogen). Because of this process linear features on a planet will be very emphasized.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The current geometry of mid ocean ridges and subduction zones does fall into a strong north-south pattern (Exceptions are Antarctica and the Aleutian trench). This might also be due to the fact that the plates form a system that in all its complexity still strives for lower stress and effective heat transport. In this case a parallel system of mid-ocean-ridges and subduction zones might be more favourable than a totally random alignment of those features.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The dynamics of the inner Earth are of course not independent of the plates and it is difficult to assign causality. Nonetheless you could again think of a complex system that seeks for efficiency (pragmatism if you will). With subduction plates being plate-shaped, circulation above and beneath them will probably be more stable in a cylindrical fashion. So the heat distribution on the upwelling side of the circulation should also create linear features. In any case we just happen to live in a time where the system went for a North-South oriented minimum.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Continuing this thought process we can also find an explanation why features in this tectonic-north-south part of the world are oriented in this way. Many north-south striking islands have north-south striking back-arc-basins that separate them from their main land masses. And peninsulas are sometimes the arms of failed rifts or the tapering of back-arc-basins. Outside of this prevalent orientation we see features like Nowaja Semlja with very different orientations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But be cautious with this theory. Assigning each feature on Earth to a north-south and east-west orientation gives you a 50 % chance that a randomly aligned feature will confirm your theory. Even four directions still give you 25 % chance. So the more directions you consider the harder it is to prove the theory. I am not aware of anybody doing a global peninsula inventory, so it would be interesting to see this.&lt;/p&gt;&#xA;" OwnerUserId="23" LastActivityDate="2014-05-12T17:52:03.247" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="909" PostTypeId="1" CreationDate="2014-05-12T18:54:08.300" Score="22" ViewCount="700" Body="&lt;p&gt;As can be seen from the below data, for the past year or so (2014), sea ice surrounding Antarctica has been well above normal.  Currently, Antarctic sea ice is at an all-time record high for this time of year, 1,344,000 square kilometers above normal (or about the size of Spain, France and Germany put together).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any explanation for such an extreme excess of sea ice around Antarctica recently?    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/DtLxi.png&quot; alt=&quot;Antarctic Sea Ice&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/kI2Y7.png&quot; alt=&quot;Antarctic See Ice anomaly&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source of data is the &lt;a href=&quot;http://nsidc.org/arcticseaicenews/2014/05/spring-unloaded/&quot; rel=&quot;noreferrer&quot;&gt;US National Snow and Ice Data Center sea ice news for April 2014&lt;/a&gt; (for the upper graph) and University of Illinois's &quot;&lt;a href=&quot;http://arctic.atmos.uiuc.edu/cryosphere/&quot; rel=&quot;noreferrer&quot;&gt;The Cryosphere Today&lt;/a&gt;&quot; (for the lower graph).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the above link, the National Snow and Ice Data Center states &quot;Antarctic sea ice extent for April 2014 reached 9.00 million square kilometers (3.47 million square miles), the largest ice extent on record by a significant margin.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Update 6/30/2014&lt;/strong&gt; :&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now the anomalously high southern sea ice has reached a record level for any time of year, at more than 2 million square kilometers above normal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/WNExG.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="725" LastEditDate="2014-12-01T21:47:51.570" LastActivityDate="2015-04-25T10:59:14.280" Title="Is there any explanation for the large amount of sea ice around Antarctica in 2014?" Tags="|antarctic|sea-ice|cryosphere|" AnswerCount="3" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="910" PostTypeId="2" ParentId="878" CreationDate="2014-05-12T19:04:08.270" Score="18" Body="&lt;p&gt;You ask what we should change to better predict earthquakes, and I'd think almost everything. As geophysicists we might know the &lt;strong&gt;what&lt;/strong&gt; of earthquake detonation, but are relatively blind  at the &lt;strong&gt;how&lt;/strong&gt;. There is a strong group of scientists who feel that single event prediction is &lt;strong&gt;NOT&lt;/strong&gt; a realistic goal, and may perhaps be impossible. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some good guesses as to why this is still a problem:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Geophysicists still do not perfectly understand &lt;a href=&quot;http://en.wikipedia.org/wiki/Elastic-rebound_theory&quot;&gt;elastic rebound theory&lt;/a&gt;, as our earthquake simulations require assumptions that are not in line with the classical model.&lt;/li&gt;&#xA;&lt;li&gt;The equations governing earthquakes are most definitely &lt;a href=&quot;http://en.wikipedia.org/wiki/Nonlinear_system&quot;&gt;non-linear&lt;/a&gt;, and the mathematical techniques that might describe earthquake motion and eruption might not even exist yet. An example of a situation like this is &lt;a href=&quot;http://en.wikipedia.org/wiki/Knot_theory&quot;&gt;Knot Theory&lt;/a&gt; and DNA, where it was very difficult to mathematically represent DNA structures until Knot Theory came about (it is probably still difficult, but at least there is maths for it). &lt;/li&gt;&#xA;&lt;li&gt;The theory of plate tectonics, the overall cause of earthquakes, is not fully complete, and a mapping and characterization of its mantle flow is not understood.&lt;/li&gt;&#xA;&lt;li&gt;Modeling the effects of &lt;a href=&quot;http://en.wikipedia.org/wiki/Seismic_anisotropy&quot;&gt;seismic anisotropy&lt;/a&gt;, most notably lattice preferred orientation, is not understood. Most notably, its role in mantle wedge dynamics. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;But these are just guesses, and really, thats all we have. Shots in the dark.  &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-05-12T19:04:08.270" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="912" PostTypeId="2" ParentId="895" CreationDate="2014-05-13T00:08:26.453" Score="7" Body="&lt;p&gt;Downwelling speeds in the deep water formation areas are likely not significant when compared with the settling speeds of most sediment particles. While deep waters have clearly defined oxygen and nutrient characteristics, it does not seem likely that they can have a particular sedimentary character.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The deep water circulation associated with the meridional overturning circulation (MOC), while not very intense (a few cm/s), can transport some of the finer sediment classes along with it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main sedimentary signal is likely associated with calcium carbonate. The shutdown of the MOC could have significant effects on the CaCO3 balance (&lt;a href=&quot;http://dx.doi.org/10.1029/2007JG000669&quot;&gt;Chikamoto et al., 2008&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-05-13T00:08:26.453" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="913" PostTypeId="2" ParentId="893" CreationDate="2014-05-13T11:59:09.073" Score="6" Body="&lt;p&gt;A difference of accuracy between weather models can be due to different factors, one of these is certainly the availability of &quot;good&quot; initialization data. As pointed out in Bradley Ballish (NOAA/NCEP) in his &lt;a href=&quot;http://www.emc.ncep.noaa.gov/gmb/wd23ja/presentations/dropout/AMS%20Oral%20Presentation%20Ballish.ppt&quot;&gt;AMS presentation&lt;/a&gt; the accuracy of GFS has improved drastically when ECMWf initaliziation data have been used. Furthermore, I think there is a big difference in computational power between the two centers, ECMWF center has bigger and faster supercomputers.  &lt;/p&gt;&#xA;" OwnerUserId="9" LastActivityDate="2014-05-13T11:59:09.073" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="915" PostTypeId="1" AcceptedAnswerId="916" CreationDate="2014-05-13T15:00:03.147" Score="14" ViewCount="325" Body="&lt;p&gt;I'm thinking biggest in volume, regarding which area of the planet will contribute more to a raising in sea level - were the ice in those regions to melt.&lt;/p&gt;&#xA;&lt;p&gt;I can basically think of two candidates, namely Greenland and Antarctica. So maybe some comparison between the contributions of the two would be great.&lt;/p&gt;&#xA;" OwnerUserId="471" LastEditorUserId="6467" LastEditDate="2021-07-07T22:46:28.407" LastActivityDate="2021-07-07T22:46:28.407" Title="Where does the biggest land-based ice cap reside?" Tags="|climate-change|sea-level|glaciology|ice-sheets|antarctica|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="916" PostTypeId="2" ParentId="915" CreationDate="2014-05-13T15:32:14.703" Score="13" Body="&lt;p&gt;Antarctica is the ice sheet (cap) that will contribute most IF it would melt completely. The &lt;a href=&quot;http://www.climatechange2013.org/images/report/WG1AR5_Chapter04_FINAL.pdf&quot;&gt;2013 IPCC report (Ch. 4, the Cryosphere)&lt;/a&gt; provides an estimate of 58.3 m of sea level equivalent (sle). Greenland would if completely wasted away provide 7.36 m sle. Remaining glaciers provide an additional 0.41 m sle. The likelihood of Antarctica completely wasting away seems unlikely with our current understanding although the so-called West Antarctic Ice sheet (closes to the Antarctic Penninsula is sitting with its base deep below the current sea level) is far more likely to be lost than the East Antarctic Ice Sheet. Hence the contribution from Antarctica is likely less than the maximum number. Greenland on the other hand is thought to have a &quot;point of no return&quot; beyond which it will irreversibly be lost given the current or warmer climate. Since Greenland is mostly land-based, much of the mass loss will be by surface melting while West-Antarctica can lose much of its mass by ice berg calving which is likely a much faster loss mechanism. Estimates on the scenarios are emerging but there are still uncertainties and there may also be feedbacks that we either do not fully understand or have not yet seen that can change these scenarios (particularly for West-Antarctica). This &lt;a href=&quot;http://www.sciencemag.org/content/early/2014/05/12/science.1249055&quot;&gt;Science article&lt;/a&gt;&#xA;published online May 12 2014 is a good example of emerging research on the stability issues of West Antarctica.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="87" LastEditDate="2014-05-14T07:17:24.110" LastActivityDate="2014-05-14T07:17:24.110" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="917" PostTypeId="2" ParentId="909" CreationDate="2014-05-13T19:23:10.670" Score="9" Body="&lt;p&gt;&lt;em&gt;(Note: this is based on what I found in literature.  Sea ice is not my expertise.)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Short answer: We don't know.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It may be related to changes in atmospheric temperature, wind stress, precipitation, ocean temperature, changes in coastal polynas, or other factors.  The usual way to explain observed behaviour is through models.  However, models are currently unable to represent the observed behavior.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The IPCC AR5 WG1 report, chapter 4 (Vaughan et al., 2013), addresses Antarctic sea ice.  Firstly, as your question addresses overall winter sea ice, it is important to note that trends vary as a function of season and location:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The seasonal trends are significant mainly near the ice edge, with the values alternating between positive and negative around Antarctica. Such an alternating pattern is similar to that described previously as the Antarctic Circumpolar Wave (ACW) (White and Peterson, 1996) but the ACW may not be associated with the trends because the trends have been strongly positive in the Ross Sea and negative in the Bellingshausen/Amundsen seas but with almost no trend in the other regions (Comiso et al., 2011). In the winter, negative trends are evident at the tip of the Antarctic Peninsula and the western part of the Weddell Sea, while positive trends are prevalent in the Ross Sea. The patterns in spring are very similar to those of winter, whereas in summer and autumn negative trends are mainly confined to the Bellingshausen/Amundsen seas, while positive trends are dominant in the Ross Sea and the Weddell Sea.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.climatechange2013.org/images/figures/WGI_AR5_Fig4-7.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hSem3.jpg&quot; alt=&quot;IPCC AR5 WG1 Figure 4.7&quot;&gt;&lt;/a&gt;&#xA;&lt;br /&gt; &lt;sup&gt;&lt;em&gt;(a) Plots of decadal averages of daily sea ice extent in the Antarctic (1979–1988 in red, 1989–1998 in blue, 1999– 2008 in gold) and a 4-year average daily ice extent from 2009 to 2012 in black. Maps indicate ice concentration trends (1979–2012) in (b) winter, (c) spring, (d) summer and (e) autumn (updated from Comiso, 2010).&lt;/em&gt; Source: Vaughan et al. (2013)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A recent article on the topic is by Holland and Kwok (2012).  In the abstract, they summarise:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The sea-ice cover around Antarctica has experienced a slight expansion in area over the past decades&lt;sup&gt;1, 2&lt;/sup&gt;. This small overall increase is the sum of much larger opposing trends in different sectors that have been proposed to result from changes in atmospheric temperature or wind stress&lt;sup&gt;3, 4, 5&lt;/sup&gt;, precipitation&lt;sup&gt;6, 7&lt;/sup&gt;, ocean temperature8, and atmosphere or ocean feedbacks&lt;sup&gt;9, 10&lt;/sup&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The article itself is behind a paywall.  Back to the IPCC AR5 WG1 chapter 4 (Vaughan et al., 2013):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;An increase in the extent of coastal polynyas in the Ross Sea caused&#xA;  increased ice production (latent heat effect) that is primarily respon-&#xA;  sible for the positive trend in ice extent in the Antarctic (Comiso et&#xA;  al., 2011). Drucker et al. (2011) show that in the Ross Sea, the net&#xA;  ice export equals the annual ice production in the Ross Sea polynya&#xA;  (approximately 400 km&lt;sup&gt;3&lt;/sup&gt; in 1992), and that ice production increased by&#xA;  20 km&lt;sup&gt;3&lt;/sup&gt; yr&lt;sup&gt;–1&lt;/sup&gt; from 1992 to 2008.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, the best answer we can give so far is: we don't really know.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Vaughan, D.G., J.C. Comiso, I. Allison, J. Carrasco, G. Kaser, R. Kwok, P. Mote, T. Murray, F. Paul, J. Ren, E. Rignot, O. Solomina, K. Steffen and T. Zhang, 2013: Observations: Cryosphere. In: Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change [Stocker, T.F., D. Qin, G.-K. Plattner, M. Tignor, S.K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex and P.M. Midgley (eds.)]. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Holland, Paul R., and Ron Kwok. &quot;Wind-driven trends in Antarctic sea-ice drift.&quot; Nature Geoscience 5.12 (2012): 872-875.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="181" LastEditDate="2014-05-23T12:37:01.237" LastActivityDate="2014-05-23T12:37:01.237" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="918" PostTypeId="2" ParentId="909" CreationDate="2014-05-13T20:51:39.100" Score="21" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Antarctic sea ice extent for April 2014 reached 9.00 million square kilometers (3.47 million square miles), the largest ice extent on record by a significant margin.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Is there any explanation for such an extreme excess of sea ice around Antarctica recently?  &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'll give four separate answers:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;It's not as significant an increase as you think.&lt;/li&gt;&#xA;&lt;li&gt;The Interdecadal Pacific Oscillation is strongly in its negative phase.&lt;/li&gt;&#xA;&lt;li&gt;The Southern Annular Mode is at a 1000 year high.&lt;/li&gt;&#xA;&lt;li&gt;Natural and man-made variations have collectively caused increased melting of the Antarctica ice sheet.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;It's not as significant an increase as you think.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's important to remember what that &quot;largest ice extent on record&quot; means. That &quot;on record&quot; means &lt;em&gt;in the satellite era&lt;/em&gt;. Data from before the satellite era (pre-1981) are rather spotty. Except they aren't.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's a nice proxy for sea ice extent, at least during Antarctic summer, in the locations at which whalers made their catches and established their factory ships (Williams 1997). In the first half of the 20th century, whalers sought species that concentrated near the edge of the Antarctic sea ice. By the early 1930s whalers had developed a practice of anchoring factory ships within 20 km of the ice edge and followed the ice southward as summer progressed. This practice continued throughout the 1930s and resumed after WWII through to the mid 1950s. The practice was later restarted in the mid to late 1970s. Every whale caught by Norwegian whalers was tagged with date, latitude, and longitude. The practice of setting up shop near the ice edge gave Williams a nice way of estimating the pre-satellite era ice extent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What Williams found was that summer Antarctic sea ice suffered a massive decline that continued throughout the 1950s and 1960s. The ice levels we are seeing now, at least during Antarctic summer, are on par with the levels seen eighty years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The Interdecadal Pacific Oscillation is strongly in its negative phase.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Interdecadal Pacific Oscillation (IPO) is highly correlated with a hiatus in perceived global warming and also with increased precipitation in the Antarctic (Meehl 2013). An increase in precipitation means that surface waters are less salty (increasing the freezing point) and cooler. The combination of reduced sea surface temperatures and reduced salinity makes for increased ice formation during the Antarctic winter during periods when the IPO is in its negative phase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The Southern Annular Mode is at a 1000 year high.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It has long been suspect that stronger winds are one of the causes of the increase in the Antarctic sea ice levels (Zhang 2007, Zhang 2014). Winds help create polynyas, open areas of water surrounded by ice. That open water is subject to freezing during the Antarctic winter. Not only are the winds strong now, they are stronger than they have been for at least 1000 years (Abram 2014).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Natural and man-made variations have collectively caused increased melting of the Antarctica ice sheet.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just as increased precipitation leads to increased ice formation, so does increased melting of the continental Antarctic ice sheet. And the ice sheet is melting (Shepherd 2012, Rignot 2013). Gravity measurements from the GRACE satellites, combined with ice height measurements from ICESat collectively show that Western Antarctica and the Antarctica Peninsula are decreasing in mass, and at a significantly greater rate than the slight increase in the mass of the Eastern Antarctica ice sheet. This influx of cold, fresh water during the Antarctic summer makes for increased sea ice production during the Antarctic winter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2235.html&quot;&gt;Abram, N. et al., &quot;Evolution of the Southern Annular Mode during the past millennium,&quot; &lt;em&gt;Nature Clim. Change&lt;/em&gt;, (2014)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.cawcr.gov.au/staff/jma/Decadal.trends.Meehl.JClim.2013.pdf&quot;&gt;Meehl, G. et al., &quot;Externally forced and internally generated decadal climate variability associated with the interdecadal pacific oscillation,&quot;&lt;em&gt;J. Climate&lt;/em&gt; 26 (2013), 7298–7310.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencemag.org/content/338/6111/1183&quot;&gt;Shepherd, A. et al., &quot;A Reconciled Estimate of Ice-Sheet Mass Balance,&quot; &lt;em&gt;Science&lt;/em&gt; 338.6111 (2012): 1183-1189.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencemag.org/content/341/6143/266.abstract&quot;&gt;Rignot, E. et al., &quot;Ice-Shelf Melting Around Antarctica,&quot; &lt;em&gt;Science&lt;/em&gt; 341.6143 (2013): 266-270.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://data.aad.gov.au/analysis/crc/eceawiki/files/delamare1997.pdf&quot;&gt;William, K. &quot;Abrupt mid-twentieth-century decline in Antarctic sea-ice extent from whaling records,&quot; &lt;em&gt;Nature&lt;/em&gt; 389.6646 (1997): 57-60.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/JCLI4136.1&quot;&gt;Zhang, J., &quot;Increasing Antarctic sea ice under warming atmospheric and oceanic conditions,&quot; J. Climate, 20 (2007), 2515-2529.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-12-00139.1&quot;&gt;Zhang, J., &quot;Modeling the Impact of Wind Intensification on Antarctic Sea Ice Volume,&quot; J. Climate, 27 (2014), 202–214.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2014-05-14T02:57:13.543" LastActivityDate="2014-05-14T02:57:13.543" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="919" PostTypeId="2" ParentId="874" CreationDate="2014-05-13T22:22:38.290" Score="17" Body="&lt;p&gt;&lt;strong&gt;Note: This response is bereft of references. I'll try to add them later.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;There is no definitive answer. There are a lot of conjectures, however.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whatever the cause, the Earth is markedly void of carbon compared to Venus. The amount of CO&lt;sub&gt;2&lt;/sub&gt; in Venus atmosphere corresponds to a 0.88 km thick layer of carbonate. The Earth's geosphere (lithosphere plus oceans plus atmosphere) collectively contains about half that amount of carbon, almost all of it locked up in the lithosphere. The huge amount of carbon in Venus atmosphere versus the paucity of carbon in the Earth's atmosphere is the primary factor that distinguishes the two atmospheres.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Planet formation&lt;/em&gt;. The leading hypothesis regarding the late formation of the Earth is the giant impact hypothesis. Multiple simulations suggest that this collision had to be rather oblique. An oblique collision between a Mars-sized body and a not-quite Earth-sized body would have drastically changed the Earth's rotation rate prior to and after that collision. If the Earth was rotating very fast prior to the collision, that fast rotation combined with the collision could have resulted in the Earth losing a large chunk of its primordial atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Venus does not have a large Moon. That suggests that it's formation was a bit less tumultuous than the formation of the Earth. With no big collision to eject that primordial atmosphere, Venus may well have been operating in runaway greenhouse mode from the very onset.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Water.&lt;/em&gt; Whether Venus first had free water on its surface or in its atmosphere has long been a subject of debate. Venus is now nearly devoid of water. If water was present in Venus early atmosphere, it would have served to even more strongly magnify the already huge greenhouse effect of a thick atmosphere that is opaque in the thermal infrared frequencies. If the very young Venus did have liquid water on its surface, it wouldn't have lasted very long.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Plate tectonics.&lt;/em&gt; One of the consequences of a very thick atmosphere and no liquid water is no plate tectonics. Venus has a very thick greenhouse atmosphere, which makes for a very hot surface. The high temperature of Venus's surface means the surface healed itself too rapidly. Plates couldn't form on Venus (Bercovici 2014). Water is an important lubricant for plate tectonics, particularly for subduction (Mian 1990). (But also see (Fei 2013) for an opposing view.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With no plate tectonics, there was no mechanism to bury carbon inside of Venus. Plate tectonics developed fairly early on in Earth's history. By the time the Sun became hot enough (the early Sun was faint), the Earth had already started the process of sequestering away carbon into the lithosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Life.&lt;/em&gt; Life loves carbon. It is one of the key agents by which atmospheric carbon is transferred to the lithosphere. Life apparently never had a chance on Venus.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/nature/journal/v508/n7497/full/nature13072.html&quot;&gt;Bercovici D. and Ricard Y., &quot;Plate tectonics, damage and inheritance,&quot; &lt;em&gt;Nature&lt;/em&gt; 508, 513-516 (2014)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/nature/journal/v498/n7453/abs/nature12193.html&quot;&gt;Fei et al., &quot;Small effect of water on upper-mantle rheology based on silicon self-diffusion coefficients,&quot; &lt;em&gt;Nature&lt;/em&gt; 498, 213–215 (2013)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1111/j.1365-3121.1990.tb00102.x/abstract&quot;&gt;Mian Z. and Tozer D., &quot;No water, no plate tectonics: convective heat transfer and the planetary surfaces of Venus and Earth,&quot; &lt;em&gt;Terra Nova&lt;/em&gt; 2:5, 455-459 (1990)&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2014-05-14T12:55:05.653" LastActivityDate="2014-05-14T12:55:05.653" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="920" PostTypeId="1" CreationDate="2014-05-13T23:50:52.007" Score="22" ViewCount="732" Body="&lt;p&gt;It is well-known that we can learn a lot about the structure of the lower crust, mantle, and core by observing the ways in which they refract different kinds of seismic waves. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do we have any &lt;em&gt;other&lt;/em&gt; ways of imaging the deeper parts of the Earth, though? &lt;/p&gt;&#xA;" OwnerUserId="67" LastEditorUserId="67" LastEditDate="2014-05-26T00:03:51.510" LastActivityDate="2021-10-13T07:25:24.407" Title="Are there any techniques for imaging the deep Earth besides seismic waves?" Tags="|geophysics|seismology|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="921" PostTypeId="2" ParentId="878" CreationDate="2014-05-14T03:53:04.423" Score="14" Body="&lt;p&gt;Besides the theoretical limitations that @Neo talks about, there is also a great data gap in our knowledge. To predict an earthquake, we would need to know:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The 3D geometry of all major, and possibly minor, fault zones&lt;/li&gt;&#xA;&lt;li&gt;The distribution of stress in the lithosphere, at least close to the fault zones but possibly more&lt;/li&gt;&#xA;&lt;li&gt;The physical characteristics of the rocks in faults (friction, brittleness, etc)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Our knowledge of the above is limited, at best. So to accurately predict earthquakes we'd need not only better equations, but also &lt;strong&gt;a lot&lt;/strong&gt; more data. &lt;/p&gt;&#xA;" OwnerUserId="137" LastActivityDate="2014-05-14T03:53:04.423" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="922" PostTypeId="1" CreationDate="2014-05-14T06:35:06.487" Score="19" ViewCount="574" Body="&lt;p&gt;Given what we know about the physical mechanisms underlying earthquakes, what do the theoretical upper bounds on the magnitude of an earthquake look like? What physical phenomena impose those upper bounds?&lt;/p&gt;&#xA;&lt;p&gt;Assume that we're talking about the &amp;quot;modern&amp;quot; Earth, i.e. from the past 4 billion years, after the Earth was fully formed. Also assume that only natural phenomena are involved - no nuclear weapons or &lt;a href=&quot;http://wiki.uqm.stack.nl/Deep_Child&quot; rel=&quot;noreferrer&quot;&gt;Deep Children&lt;/a&gt; or anything of the sort.&lt;/p&gt;&#xA;&lt;p&gt;If it makes a difference, I would like to know what the answer looks like in two cases:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;No impact events are involved - the earthquake is generated by purely terrestrial phenomena&lt;/li&gt;&#xA;&lt;li&gt;Arbitrarily large impact events are involved, provided that the Earth still looks &amp;quot;roughly the same&amp;quot; (defined however makes sense to you) after the impact&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;We have a trivial upper bound of moment magnitude ~25 for the former case, since the energy released by a magnitude-25 earthquake is roughly equal to the total mass-energy of the Earth&lt;sup&gt;1&lt;/sup&gt; - but I'm sure you folks know of tighter bounds than that. :)&lt;/p&gt;&#xA;&lt;p&gt;(cf. the question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/875/are-richter-magnitude-10-earthquakes-possible&quot;&gt;Are Richter-magnitude 10 earthquakes possible?&lt;/a&gt; - but most of the answers there are from a statistical perspective, not a physical perspective.)&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;h2&gt;Notes&lt;/h2&gt;&#xA;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt; As we know, the total mass-energy content of a system is given by&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$E = \sqrt{(mc^2)^2 + (pc)^2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Since the Earth's motion (both translational and rotational) is non-relativistic, we discard the momentum term as negligible and simply write &lt;span class=&quot;math-container&quot;&gt;$E = m_\text{Earth}c^2$&lt;/span&gt;. Using &lt;a href=&quot;http://en.wikipedia.org/wiki/Mass_of_Earth&quot; rel=&quot;noreferrer&quot;&gt;&lt;span class=&quot;math-container&quot;&gt;$m_\text{Earth} = 6 \times 10^{24}\ \mathrm{kg}$&lt;/span&gt;&lt;/a&gt;, this gives us &lt;span class=&quot;math-container&quot;&gt;$E = 5 \times 10^{41}\ \mathrm{J}$&lt;/span&gt;. Converting this to a moment magnitude using&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://earthquake.usgs.gov/learn/topics/measure.php&quot; rel=&quot;noreferrer&quot;&gt;&lt;span class=&quot;math-container&quot;&gt;$$M = \frac{2}{3} \log_{10} \left(\frac{E}{1\ \mathrm{N} \cdot \mathrm{m}}\right) - 2.9$$&lt;/span&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;we get &lt;span class=&quot;math-container&quot;&gt;$\boxed{M \approx 25}$&lt;/span&gt;.&lt;/p&gt;&#xA;" OwnerUserId="67" LastEditorUserId="-1" LastEditorDisplayName="user12525" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-04-25T08:04:49.643" Title="What are the physical upper bounds on the magnitude of an earthquake?" Tags="|geology|geophysics|earthquakes|seismology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="923" PostTypeId="1" CreationDate="2014-05-14T06:58:12.647" Score="12" ViewCount="430" Body="&lt;p&gt;While the project was deemed a failure (see below), does the upper atmospheric acoustic waveguide exist?&lt;/p&gt;&#xA;&lt;p&gt;What are the propagation losses for low-frequency sounds?&lt;/p&gt;&#xA;&lt;p&gt;Where can one find further information on the acoustical characteristics of the upper atmosphere?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;h2&gt;PROJECT MOGUL&lt;/h2&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Project MOGUL was first conceived by Dr. Maurice Ewing of Columbia University, NY, and Woods Hole Oceanographic Institution, MA. Dr. Ewing had conducted considerable research for the Navy during World War II, studying, among other things, the &amp;quot;sound channel&amp;quot; in the ocean. He proved that explosions could be heard thousands of miles away with underwater microphones placed at a predetermined depth within the sound channel. He theorized that since sound waves generated by explosions could be carried by currents deep within the ocean, they might be similarly transmitted within a sound channel in the upper atmosphere. The military application of this theory was the long-range detection of sound waves generated by Soviet nuclear detonations and the acoustical signatures of ballistic missiles as they traversed the upper atmosphere. He presented his theory to General Carl Spaatz, Chief of Staff of the Army Air Forces, in the fall Of 1945. ...&lt;/p&gt;&#xA;&lt;p&gt;...By December 1948, serious concerns had arisen regarding the feasibility of the project as first conceived. Even though the principle on which the project was based was determined to be sound, questions concerning cost, security, and practicality were discussed-that ultimately led to the disbandment of the project, and Project MOGUL as first conceived was never put into operational use. ...&lt;/p&gt;&#xA;&lt;p&gt;...The primary scientist for MOGUL was Dr. James Peoples, assisted by Albert P. Crary, the Field Operations Director. Both scientists had previous associations with Dr. Ewing: Dr. Peoples at Columbia, and A.P. Crary at Woods Hole. Both scientists were assigned to MOGUL for the entire length of the project. ...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;h2&gt;References&lt;/h2&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Project_Mogul&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia on Project Mogul&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://web.archive.org/web/20140116121941/http://muller.lbl.gov/teaching/physics10/Roswell/USMogulReport.html&quot; rel=&quot;noreferrer&quot;&gt;A background document on Mogul from Berkeley&lt;/a&gt; - a lecture course by &lt;a href=&quot;https://en.wikipedia.org/wiki/Richard_A._Muller&quot; rel=&quot;noreferrer&quot;&gt;Prof.Muller&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="269" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-07-22T19:39:07.437" Title="Project Mogul: Does upper atmosphere indeed have a sound waveguide channel?" Tags="|upper-atmosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="924" PostTypeId="1" AcceptedAnswerId="927" CreationDate="2014-05-14T08:56:35.237" Score="13" ViewCount="2153" Body="&lt;p&gt;I wonder whether someone knows a clear definition/description of&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Robust diagnostic models&#xA;   &lt;em&gt;Forcing with data from initial state aimed at future predictions?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Prognostic models&#xA;   &lt;em&gt;Tie model results back to observations using a relaxation factor?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;'Googling' didn't help me much unfortunately. &lt;/p&gt;&#xA;" OwnerUserId="475" LastEditorUserId="475" LastEditDate="2014-05-14T09:13:08.767" LastActivityDate="2018-11-09T00:12:34.093" Title="Model types: Robust diagnostic versus prognostic" Tags="|models|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="925" PostTypeId="2" ParentId="861" CreationDate="2014-05-14T12:12:24.257" Score="5" Body="&lt;p&gt;A good explanation is found at the University of Bourgogne site &lt;a href=&quot;http://icb.u-bourgogne.fr/omr/SMA/Methane/&quot;&gt;MODELING THE ABSORPTION SPECTRUM OF METHANE&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Although it is a small and simple molecule, its rovibrational spectroscopy is very complicated. This is mainly due to the high symmetry of this tetrahedral system (which leads to the existence of many degeneracies) and to its intricated vibrational structure. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Vibrational and Rotational-vibrational energy level diagrams are available at the site.  &lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2014-05-14T13:23:04.290" LastActivityDate="2014-05-14T13:23:04.290" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="926" PostTypeId="2" ParentId="415" CreationDate="2014-05-14T12:43:43.083" Score="8" Body="&lt;p&gt;The phosphorous sinks are the ocean and ocean sediments.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ocean holds $3 \times 10^{15}$ moles of phosphorous.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The annual amount of phosphorous input into the ocean, as well as the amount of burial of phosphorous as sediment is on the order of $10^{10}$ moles. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sediment is of three categories:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Phosphorous associated with calcium carbonate&lt;/li&gt;&#xA;&lt;li&gt;Organic phosphorous (associated with organic carbon)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Apatite&quot; rel=&quot;nofollow&quot;&gt;Apatite&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;http://web.mit.edu/qhorn/Public/Reef%20Aquariums/Phosphorus%20articles/Delaney%20Global%20Bio%20Cyc%2012%204%201998.pdf&quot; rel=&quot;nofollow&quot;&gt;Phosphorous Accumulation in Marine Sediments and the Oceanic Phosphorous Cycle&lt;/a&gt; for a detailed analysis.&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2014-09-30T14:01:29.107" LastActivityDate="2014-09-30T14:01:29.107" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="927" PostTypeId="2" ParentId="924" CreationDate="2014-05-14T15:56:28.463" Score="9" Body="&lt;p&gt;As far as I know in the ocean modeling community the terms diagnostic and prognostic have quite different meanings from what you are stating. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A prognostic simulation is used to predict future state of the system (forecast) using the model equations. The model is initialized with the initial conditions and it is used to predict using the Navier-Stokes equations the future ocean state under specified boundary conditions. There is no constraint by observations because the model numerically follows the specified equations. In the case of models with data assimilation, the prognostic solution is statistically modified (e.g., Kalman filter, adjoint method) to optimally adjust to the observations, but the new solution can't be considered prognostic as there has been a departure from the primitive forward (Navier-Stokes) equations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, a diagnostic simulation does not provide a prediction of the fluid state. There is no time-evolution based on the model equations. An example of such simulation is the case in which the velocity field is calculated based on a fixed density (temperature and salinity) field. While these simulations can be useful for short-term ocean state estimation, they can't be used for ocean state evolution as the dynamics are restricted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as I understand it, this is the standard in the ocean modeling community, but I don't know if it can be expanded to other fields.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-05-14T15:56:28.463" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="928" PostTypeId="5" CreationDate="2014-05-14T17:06:22.690" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-05-14T17:06:22.690" LastActivityDate="2014-05-14T17:06:22.690" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="929" PostTypeId="4" CreationDate="2014-05-14T17:06:22.690" Score="0" Body="The multi-disciplinary study of the geomorphology, geology, chemistry, meteorology, oceanography, hydrology, astronomy and astrophysics of the planets and other objects within the solar system." OwnerUserId="477" LastEditorUserId="192" LastEditDate="2015-04-05T23:38:55.293" LastActivityDate="2015-04-05T23:38:55.293" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="930" PostTypeId="1" CreationDate="2014-05-15T01:04:31.910" Score="16" ViewCount="127" Body="&lt;p&gt;In the recently published article by Kossin et al. (Nature, 2014, &lt;a href=&quot;http://dx.doi.org/10.1038/nature13278&quot;&gt;dx.doi.org/10.1038/nature13278&lt;/a&gt;), they show that there is a trend toward poleward migration of the location of tropical cyclone (hurricanes and typhoons) maximum intensity in most areas of the world. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Their proposed explanation focuses on the tropical expansion (the increasing area of the world where tropical phenomena is observed has expanded in time). Is there some alternative explanation for the poleward migration of the hurricanes? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The shift seems to be occurring in the Pacific and Indian Oceans but not in the Atlantic. How can we explain that difference?&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-06-20T15:47:53.477" Title="Is the poleward migration of the maximum intensity of cyclones a result of tropical expansion or are there some other contributing factors?" Tags="|atmosphere|tropical-cyclone|" AnswerCount="1" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="931" PostTypeId="5" CreationDate="2014-05-15T05:24:27.110" Score="0" Body="&lt;p&gt;The &lt;a href=&quot;http://en.wikipedia.org/wiki/El_Ni%C3%B1o_Southern_Oscillation&quot; rel=&quot;nofollow noreferrer&quot;&gt;El Niño Southern Oscillation&lt;/a&gt; is an oceanographical meteorological phenomenon in the tropical eastern Pacific Ocean. Its main manifestation is anomalously warm or cold sea surface temperatures, with an associated variation in air pressure. A warming period is known as &lt;a href=&quot;http://en.wikipedia.org/wiki/El_Ni%C3%B1o&quot; rel=&quot;nofollow noreferrer&quot;&gt;El Niño&lt;/a&gt;; a cooling period is known as &lt;a href=&quot;http://en.wikipedia.org/wiki/La_Ni%C3%B1a&quot; rel=&quot;nofollow noreferrer&quot;&gt;La Niña&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="219" LastEditorUserId="2958" LastEditDate="2018-10-22T17:52:19.687" LastActivityDate="2018-10-22T17:52:19.687" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="932" PostTypeId="4" CreationDate="2014-05-15T05:24:27.110" Score="0" Body="The El Niño Southern Oscillation, including El Niño and La Ninã" OwnerUserId="124" LastEditorUserId="219" LastEditDate="2014-12-11T22:39:00.713" LastActivityDate="2014-12-11T22:39:00.713" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="933" PostTypeId="1" AcceptedAnswerId="2548" CreationDate="2014-05-15T07:57:41.470" Score="11" ViewCount="282" Body="&lt;p&gt;$\varepsilon_{Nd}$ (i. e. the relative deviation of $\frac{^{143}Nd}{^{144}Nd}$ from a standard) is often used as a proxy in paleoceanography to identify the basin of origin of oceanic currents. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But what is the model behind this idea? Is this proxy purely empiric?&lt;br&gt;&#xA;Why would the Neodymium isotopic ratio vary among basins and why would this variation be stable in (geological) time?&lt;/p&gt;&#xA;" OwnerUserId="87" LastActivityDate="2014-09-30T02:52:46.613" Title="Use of Neodymium in Paleoceanography" Tags="|oceanography|geochemistry|ocean-currents|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="934" PostTypeId="1" CreationDate="2014-05-15T08:45:29.693" Score="15" ViewCount="653" Body="&lt;p&gt;In terms of uncoupled AGCM studies, I've seen people use periods within a decade (say, 5 years) as spin-up time, but I also see some people take tens of year as spin-up in some recent studies. So I'm thinking if it's related to the model resolution in different simulations. So does GCM spin-up time affected by the resolution they use? For example if the same model is run in different resolution, would the spin-up time be any different? Thanks!&lt;/p&gt;&#xA;" OwnerUserId="476" LastActivityDate="2014-07-19T03:31:21.043" Title="Will model resolution have an effect on model spin-up time?" Tags="|atmosphere|climate|models|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="935" PostTypeId="1" AcceptedAnswerId="2782" CreationDate="2014-05-15T09:04:10.843" Score="11" ViewCount="229" Body="&lt;p&gt;If fine particulate matter as a pollutant from industrial or natural sources (e.g. a desert) can be such a cause for concern in terms of (further) desertification as well as health impacts, is there a reason why there does not appear to be much action to control or solve it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For instance - you will sometimes see construction sites required to use a canopy and/or water to localize the spread of fine particulate matter to a particular site, and forestation projects can serve to anchor some land in the face of advancing desert boundaries - but such applications seem limited in their enforcement. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What more could be done to control and combat fine particulate matter (and perhaps avoid warmer, drier countries and regions from becoming dust bowls)?&lt;/p&gt;&#xA;" OwnerUserId="317" LastEditorUserId="6031" LastEditorDisplayName="user889" LastEditDate="2019-04-21T05:42:39.177" LastActivityDate="2019-04-21T05:42:39.177" Title="Fine particulate matter - Why the lack of attention? What can be done to tackle it?" Tags="|desert|pollution|pm2.5|particulates|atmospheric-dust|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="936" PostTypeId="2" ParentId="546" CreationDate="2014-05-15T13:41:24.783" Score="9" Body="&lt;p&gt;As suggested by Kossin et al., &quot;The poleward migration of the location of tropical cyclone maximum intensity,&quot; (Nature, 2014, &lt;a href=&quot;http://dx.doi.org/10.1038/nature13278&quot;&gt;dx.doi.org/10.1038/nature13278&lt;/a&gt;), the answer could be &quot;maybe&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the tropical region increases in size (tropical expansion: the increasing area of the world where tropical phenomena is observed has expanded in time) due in part to anthropogenic reasons, there might be a migration of tropical cyclones poleward. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The migration might not change the cyclone formation area, but it does seem to affect the location of maximum intensity. The migration seems to be occurring in most areas and the trend seems significant in most regions of the world except the North Atlantic, for instance.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-05-15T13:41:24.783" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="937" PostTypeId="2" ParentId="920" CreationDate="2014-05-15T18:44:26.843" Score="14" Body="&lt;p&gt;Gravity can be used to investigate the lower crust and upper mantle (see for example &lt;a href=&quot;http://dx.doi.org/10.1016%2Fj.jag.2014.02.003&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fullea et al, 2014&lt;/a&gt;). Satellite measurements of gravity could even be used to investigate deeper structures in the mantle, like subducting slabs (&lt;a href=&quot;http://dx.doi.org/10.1038%2Fngeo2063&quot; rel=&quot;nofollow noreferrer&quot;&gt;Panet, 2014&lt;/a&gt;). However, I couldn't find any use of gravity data to probe deeper, into the core for example.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;http://en.wikipedia.org/wiki/Magnetotellurics&quot; rel=&quot;nofollow noreferrer&quot;&gt;magnetotelluric method&lt;/a&gt; is sometimes used for deep crustal structure. And features of the geomagnetic field, like &lt;a href=&quot;http://en.wikipedia.org/wiki/Geomagnetic_secular_variation&quot; rel=&quot;nofollow noreferrer&quot;&gt;secular variation&lt;/a&gt;, can be inverted to investigate as far down as the outer core (&lt;a href=&quot;http://dx.doi.org/10.1016/S0031-9201(96)03187-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gubbins, 1996&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;However, the most common and well developed method to image the lower mantle and core is still through seismic waves.&lt;/p&gt;&#xA;" OwnerUserId="137" LastEditorUserId="18081" LastEditDate="2021-10-13T07:25:24.407" LastActivityDate="2021-10-13T07:25:24.407" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="938" PostTypeId="2" ParentId="557" CreationDate="2014-05-15T20:00:21.573" Score="6" Body="&lt;p&gt;Since @TomAu answered the bonus points, I'll focus on the question&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is this [seismology] the only way of measuring the inner sections of the earth?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No, it is not. Some interfaces, like the crust-mantle interface (the Moho), can be mapped using &lt;strong&gt;gravity anomalies&lt;/strong&gt;. The basic idea is that the gravity anomaly is the difference between the Earths gravity and the gravity of a reference model (usually an ellipsoid). The anomaly is usually due to an over-correction or an under-correction. In places where the crust is thinner, there is more mass than was removed in reference because the mantle is denser than the crust (places marked with a &quot;+&quot;  sign in the figure below). This excess mass creates a positive gravity anomaly. Likewise, if the crust is thicker there will be a mass deficiency (marked by the &quot;-&quot; sign) and we'll see a negative anomaly. So we can infer the topography of the Moho from these anomalies in the gravity field.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/6Rcvt.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, a radially varying density model (like the &lt;a href=&quot;http://en.wikipedia.org/wiki/Preliminary_reference_Earth_model&quot; rel=&quot;noreferrer&quot;&gt;PREM&lt;/a&gt; for seismology) is not possible to estimate from the gravity field alone. That is because there is an infinite number of combinations of this kind of model that yield the same gravity field.  &lt;/p&gt;&#xA;" OwnerUserId="137" LastActivityDate="2014-05-15T20:00:21.573" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="939" PostTypeId="1" AcceptedAnswerId="948" CreationDate="2014-05-15T23:37:46.077" Score="24" ViewCount="2224" Body="&lt;p&gt;The strength and orientation of Earth's magnetic field varies with time.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does this variation of the magnetic field have any influence upon climate? For example, is there any correlation between ice ages and strengthening or weakening or orientation of the field? &lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="28050" LastEditDate="2015-11-10T18:32:37.573" LastActivityDate="2018-10-25T00:49:42.610" Title="Does the strength of Earth's magnetic field influence its climate?" Tags="|climate|geomagnetism|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="940" PostTypeId="1" AcceptedAnswerId="946" CreationDate="2014-05-15T23:54:53.970" Score="10" ViewCount="205" Body="&lt;p&gt;In the new Cosmos series, Neil DeGrass Tyson in explaining different ways the age of the world has been determined, shows how sedimentary layers at the Grand Canyon are a fossil record of a lot of the Earth's history. He points out how each layer is (obviously) laid on top of the last, showing the chronology of various stages in the biosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I remember learning how the Colorado river &quot;carved&quot; the canyons, on a trip there as a kid. You can visualize this -- the huge open canyons being eroded over millions of years, the riverbed turning grooves into valleys until enormous mesas are separated by the river. But, if the river &quot;carved&quot; the canyons, doesn't that imply the sediment layers were exposed from the top layers down, chronologically? How was all this fossilized life embedded in rock that at one point was a mile under the surface, that was later exposed by the river's erosion?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not doubting the science at all, just trying to understand how the canyons formed. &lt;/p&gt;&#xA;" OwnerUserId="482" LastEditorUserId="64" LastEditDate="2014-05-21T03:11:29.147" LastActivityDate="2014-05-21T03:11:29.147" Title="Sediment layer chronology" Tags="|geology|earth-history|sedimentology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="941" PostTypeId="1" AcceptedAnswerId="943" CreationDate="2014-05-16T01:47:13.700" Score="14" ViewCount="2187" Body="&lt;p&gt;So we have high-resolution models like the &lt;a href=&quot;http://rapidrefresh.noaa.gov/HRRR/&quot;&gt;HRRR&lt;/a&gt; (High Resolution Rapid Refresh). But what exactly is the difference between a high-resolution model and a regular model? I realize that the higher resolution models are more accurate, but why is this? Is there more data fed into the computer?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, are there criteria that a model must meet to be called high resolution, or is it just an arbitrary name?&lt;/p&gt;&#xA;" OwnerUserId="20" LastEditorUserId="20" LastEditDate="2014-05-21T20:03:49.490" LastActivityDate="2014-05-21T20:03:49.490" Title="What is the difference between a high-resolution model and a regular model run?" Tags="|meteorology|models|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="943" PostTypeId="2" ParentId="941" CreationDate="2014-05-16T03:02:06.340" Score="22" Body="&lt;p&gt;High resolution means that the grid mesh the model uses is fine, or put another way, $dx$, $dy$, $dz$, and $dt$ are small numbers.  A model like the HRRR uses a horizontal resolution of 3 km, whereas some of the older regional models used horizontal resolutions of 30 km (though even the NAM is using 5 km these days).  Comparing resolutions to GFS and ECMWF models is a bit less straightforward because those models solve in a spherical coordinate system using spectral methods, and resolution will vary with latitude).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Higher horizontal grid resolution also implies higher vertical resolution and a smaller timestep.  The vertical resolution will be a consequence of wanting to avoid large aspect ratios in your grid box and the smaller timestep follows from the need for numerical stability (see &lt;a href=&quot;http://en.wikipedia.org/wiki/Courant%E2%80%93Friedrichs%E2%80%93Lewy_condition&quot;&gt;CFL criterion&lt;/a&gt;).  The biggest direct result of the increased resolution and decreased timestep are increased memory and drastically increased computational requirements.  Because of this, operational forecast model resolutions will be limited by how long is acceptable for the model to run before output is available, which is a function of the supercomputer crunching the numbers.  You will generally find much higher resolutions in non-forecast research settings than operationally.  For example, I simulate supercell thunderstorms with 250 m horizontal resolution, but I can also spare an entire day to simulate a few hours whereas an operational model only has a few hours to simulate many days in a much larger domain than I use.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't believe there is a specific requirement to call a model &quot;high resolution&quot; and I think you'll find that the implied resolutions will be quite different between a climate modeler and a mesoscale modeler.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Differences in accuracy in higher resolution models generally boils down to resolving more of the physics explicitly.  A model running with 30 km resolution cannot resolve convection (thunderstorms), and must parameterize this as a sub-gridscale effect.  You might see terms like &quot;cloud resolving&quot; applied to high resolution models because of this.  A model running at 3 km resolution will be able to explicitly resolve convection.  A large eddy simulation (using filtered Navier-Stokes equations) will be limited to resolving eddies on a scale based on the grid resolution, and will parameterize the smaller scales.  Please see &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0493%282003%29131%3C2394%3aRRFTSO%3E2.0.CO;2&quot;&gt;this paper&lt;/a&gt;&lt;sup&gt;1&lt;/sup&gt; for further discussion on the impact of resolution on resolving deep moist convection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, the data going into the model will make a difference (weather is chaotic and extremely sensitive to the initial conditions).  The HRRR is initialized from the &lt;a href=&quot;http://rapidrefresh.noaa.gov/&quot;&gt;RAP&lt;/a&gt; with a data assimilation period for observed radar.  RAP is currently a 13 km model but is moving to 3 km this summer. RAP gets its background fields from GFS and assimilates quite a bit of data on top of that.  While the smaller grid boxes help capture more of the physics, the quality of the data fed into the model is also helping quite a bit with accuracy because it improves the initial conditions.  &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Bryan, George H., John C. Wyngaard, J. Michael Fritsch, 2003: Resolution Requirements for the Simulation of Deep Moist Convection. &lt;em&gt;Mon. Wea. Rev.&lt;/em&gt;, &lt;strong&gt;131&lt;/strong&gt;, 2394–2416.&#xA;doi: &lt;a href=&quot;http://dx.doi.org/10.1175/1520-0493%282003%29131%3C2394%3aRRFTSO%3E2.0.CO;2&quot;&gt;http://dx.doi.org/10.1175/1520-0493(2003)131&amp;lt;2394:RRFTSO&gt;2.0.CO;2&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="64" LastEditorUserId="115" LastEditDate="2014-05-21T18:17:39.817" LastActivityDate="2014-05-21T18:17:39.817" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="944" PostTypeId="5" CreationDate="2014-05-16T04:54:46.797" Score="0" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Sea_ice&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sea ice&lt;/a&gt; arises as seawater freezes. Because ice is less dense than water, it floats on the ocean's surface. Sea ice covers about 7% of the Earth's surface and about 12% of the world's oceans. Much of the world's sea ice is enclosed within the polar ice packs in the Earth's polar regions: the Arctic and Antarctic ice packs.&lt;/p&gt;&#xA;" OwnerUserId="-1" LastEditorUserId="11908" LastEditDate="2019-02-03T19:36:03.430" LastActivityDate="2019-02-03T19:36:03.430" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="945" PostTypeId="4" CreationDate="2014-05-16T04:54:46.797" Score="0" Body="Questions about frozen seawater, not about floating icebergs." OwnerUserId="124" LastEditorUserId="124" LastEditDate="2014-05-16T21:20:30.580" LastActivityDate="2014-05-16T21:20:30.580" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="946" PostTypeId="2" ParentId="940" CreationDate="2014-05-16T13:17:58.183" Score="9" Body="&lt;p&gt;In simple big picture terms, Sediments were deposited first from the bottom upwards (as you understand). Then the area was uplifted and the river eroded from the top down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most erosion is from the top down (there are scenarios such as dissolution and caves which are relatively rare exceptions). So here in Texas we find a large amount of the center of the state was covered with Cretaceous sediments which have since eroded away. We see signs of this from &quot;outliers&quot; - basically remnant caps of Cretaceous on the tops of hills.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I say this is big picture viewpoint. The very bottom of the Grand Canyon has metamorphic rocks. And sedimentation will not have been continuous. There are gaps from erosion, uplift, etc. But yes the bottom is about 2 billion years old, and erosion of the canyon itself is &quot;relatively&quot; recent.&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorUserId="44" LastEditDate="2014-05-18T16:17:51.753" LastActivityDate="2014-05-18T16:17:51.753" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="947" PostTypeId="1" AcceptedAnswerId="951" CreationDate="2014-05-16T19:12:26.493" Score="13" ViewCount="2904" Body="&lt;p&gt;I've read in the past that extreme precipitation levels may have an effect on seismic activity, and wondered if anyone has ever analysed the La Niña / El Niño cycles to see if there is any correlation with seismic activity in the area affected by the phenomena.&lt;/p&gt;&#xA;" OwnerUserId="484" LastEditorUserId="484" LastEditDate="2023-11-15T07:50:00.433" LastActivityDate="2023-11-15T07:50:00.433" Title="Is there any correlation between La Niña/El Niño and seismic activity?" Tags="|meteorology|geology|seismology|precipitation|enso|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="948" PostTypeId="2" ParentId="939" CreationDate="2014-05-17T08:45:37.073" Score="22" Body="&lt;p&gt;There is no significant geomagnetic influence on the cycle of glacials and interglacials. I think the easiest way to determine this is to consider geomagnetic reversals. A reversal obviously involves the largest possible change in the &lt;em&gt;direction&lt;/em&gt; of the magnetic field (a full 180°). It also involves some of the largest changes in field &lt;em&gt;intensity&lt;/em&gt;, because during a reversal the field intensity drops to a small fraction of its usual value before regrowing to ‘normal’ levels (e.g. Raisbeck et al., 1985). So, if we're expecting geomagnetic field behaviour to have any influence on climate, we'd expect the most obvious effects to appear at reversals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can look for this effect by comparing a δ&lt;sup&gt;18&lt;/sup&gt;O record (which gives a proxy for global temperature and ice volume) with a record of magnetic reversals. Here's a figure of the LR04 stack from Lisiecki &amp;amp; Raymo (2005), showing those two records for the past ~5 Myr:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/lZ3ip.png&quot; alt=&quot;Lisiecki &amp;amp; Raymo (2005), fig. 4: The LR04 benthic d18O stack&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, nothing spectacular or even noticeable happens at the reversals (the black/white boundaries along the bottom of the plot). They don't seem to correspond to any particular point in the glacial/interglacial cycle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, it's likely that geomagnetic field strength has &lt;em&gt;some&lt;/em&gt; influence on climate, and that these effects are simply swamped by other influences on the spatial and temporal scales we're looking at here. The first possible effect that came to my mind was the geomagnetic field's influence on the amount of incoming cosmic rays, which in turn has an effect on cloud formation. And sure enough, it turns out that Vieira and da Silva (2006) have found such an effect. But I suspect that once you start looking at &gt;10kyr timescales and global signals, such effects get averaged out.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Lisiecki, L. E., &amp;amp; Raymo, M. E. (2005). A Pliocene‐Pleistocene stack of 57 globally distributed benthic δ&lt;sup&gt;18&lt;/sup&gt;O records. &lt;em&gt;Paleoceanography&lt;/em&gt;, 20(1).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Raisbeck, G. M., Yiou, F., Bourles, D., &amp;amp; Kent, D. V. (1985). Evidence for an increase in cosmogenic &lt;sup&gt;10&lt;/sup&gt;Be during a geomagnetic reversal. &lt;em&gt;Nature&lt;/em&gt;, 315(6017), 315-317.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Vieira, L. E. A., &amp;amp; da Silva, L. A. (2006). Geomagnetic modulation of clouds effects in the Southern Hemisphere Magnetic Anomaly through lower atmosphere cosmic ray effects. &lt;em&gt;Geophysical research letters&lt;/em&gt;, 33(14).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="94" LastActivityDate="2014-05-17T08:45:37.073" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="949" PostTypeId="2" ParentId="939" CreationDate="2014-05-17T13:59:40.780" Score="7" Body="&lt;p&gt;As Pont says, there's little evidence that the magnetic field has no observable evidence on the long term climate of earth, there was a recent study which drew a link between the solar wind strength and the frequency of lightning storms. Given that the amount of incoming charged particles from the solar wind that make it into the atmosphere is dependent on the strength of the magnetic field. &#xA;This is however short term weather not climate, however it does show that the strength of the magnetic field does have an effect on the atmospheric systems, albeit not in the long run. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Paper here: &lt;a href=&quot;http://iopscience.iop.org/1748-9326/9/5/055004/article&quot;&gt;http://iopscience.iop.org/1748-9326/9/5/055004/article&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;BBC article: &lt;a href=&quot;http://www.bbc.co.uk/news/science-environment-27406358&quot;&gt;http://www.bbc.co.uk/news/science-environment-27406358&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="389" LastActivityDate="2014-05-17T13:59:40.780" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="951" PostTypeId="2" ParentId="947" CreationDate="2014-05-19T01:43:35.413" Score="9" Body="&lt;p&gt;There is a case study from &lt;em&gt;Environmental Science&lt;/em&gt; entitled &lt;strong&gt;El Niño: A Link among Atmospheric, Oceanic, and Crustal Circulation?&lt;/strong&gt; that &lt;a href=&quot;http://www.trunity.net/sam2/view/article/51cbf4007896bb431f6aeb04/&quot; rel=&quot;noreferrer&quot;&gt;discusses &lt;/a&gt; the correlations between seismic activity and El Niño cycles in certain areas of the world, that have been documented:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A geophysicist, Daniel A. Walker, hypothesizes that a different sequence of events produces an El Niño event. Walker says that the thermal input to the oceans comes from Earth’s interior. This hypothesis is based on an intriguing correlation of seismic activity under the eastern portion of the Pacific Ocean near Easter Island and the onset of El Niño events. This correlation can be used to illustrate possible linkages among the physical systems of planet Earth and the difference between statistical correlation and physical causation.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The East Pacific Rise is located west of Easter Island. Along this rise, tectonic plates move 160–170 mm (6.3–6.7 inches) per year. This rate is one of the most rapid in the world. As a result, seismic activity along the East Pacific Rise has been studied extensively for more than thirty years. During this period scientists have tracked the number of earthquakes and the amount of energy they release.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/2JBQm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Months with the greatest number of earthquakes or months with earthquakes that release the greatest amount of energy precede the onset of El Niño events. This hints at a relationship between seismic activity and El Niño events. A simple statistical analysis suggests that if the seismic events and the El Niño events occurred randomly, the probability of finding a sequence in which periods of heightened seismic activity precede El Niño events would be 1 out of 313. &lt;em&gt;Such long odds imply that the sequence probably is not generated by random chance. Rather, there may be a physical connection between seismic activity and El Niño events&lt;/em&gt;.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;But statistical correlation should not be confused with physical causation. Correlation indicates that the timing of the two events is similar but does not mean that the two events are connected. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Scientists have come up with several explanations for how seismic activity may trigger El Niño events. These hypotheses are based on the relationship between air temperature and pressure. In general, warm air has less pressure than cold air, so hypotheses seek to explain how seismic activity along the East Pacific Rise could affect air temperature.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There are several other articles that discuss the relationship between La Niña/El Niño cycles and seismic activity, such as &lt;a href=&quot;http://rsta.royalsocietypublishing.org/content/368/1919/2481.full&quot; rel=&quot;noreferrer&quot;&gt;this article&lt;/a&gt; published by &lt;em&gt;RSTA&lt;/em&gt; entitled &lt;strong&gt;Statistical analysis of the El Niño–Southern Oscillation and sea-floor seismicity in the eastern tropical Pacific&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There also appears to be a relationship between El Niño cycles and &lt;a href=&quot;http://www.nature.com/nature/journal/v426/n6964/full/nature02101.html&quot; rel=&quot;noreferrer&quot;&gt;volcanic activity&lt;/a&gt;, as published in &lt;em&gt;Nature&lt;/em&gt;.&lt;/p&gt;&#xA;" OwnerUserId="490" LastActivityDate="2014-05-19T01:43:35.413" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="952" PostTypeId="2" ParentId="384" CreationDate="2014-05-19T08:36:26.450" Score="6" Body="&lt;p&gt;I'm not going to give an extensive account on &quot;mass extinction&quot; epistomology here but I think the first thing one has to consider is the difficulty of studying numerically paleobiodiversity (mostly because of a gappy fossil record but also an historically unbalanced sampling effort and the rock availability for some of the time periods); although, along the years, we designed better tools to compensate for those biases (see the whole bibliography of John Alroy for instance), this is still a major issue.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, the recognition of the &quot;Big Five&quot; (i. e. the five bigger mass extinctions of the Phanerozoic: End Ordovician, Late Devonian, Permian/Triassic boundary, Triassic/Jurassic boundary and Cretaceous/Paleogene boundary) basically derive from the work of &lt;strong&gt;Sepkoski (1978, 1979; Raup &amp;amp; Sepkoski 1981&lt;/strong&gt;, etc...) who studied the diversity of &lt;em&gt;marine biota&lt;/em&gt; and more specifically (judging by &lt;strong&gt;Sepkoski 1981&lt;/strong&gt;) &lt;em&gt;marine metazoans&lt;/em&gt;. As a consequence everything terrestrial and every non-metazoan (plants, protists, bacteria) are not included in the classic recognition of those events. It so happens that at least the P-T and the K-Pg events have been also recognized in some marine protists (namely foraminifera) and in terrestrial vertebrates (dinosaurs for the K-PG and many groups of 'pelycosaurs' for the P-T to name the more famous); but conceptually this is a significant bias as it may happen that the geological event driving one of those mass extinctions can only affect marine organisms (oceanic anoxia being the most obvious example).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's for the epistemology part. Now the plants themselves: as you noticed with your quote of &lt;strong&gt;Traverse (1988)&lt;/strong&gt; it is thought that the Embryophyta (i. e. land plants) have not been affected by the Big Five. This idea have since then been somewhat challenged (e. g. &lt;strong&gt;McElwain &amp;amp; Punyasena 2007&lt;/strong&gt;) with evidences that plants indeed were affected by some of those extinctions but maybe not as drastically as what we think happened for marine faunas or terrestrial vertebrates.&lt;br&gt;&#xA;It needs to be considered however that the earliest evidences for the existence of land plants date from the Silurian (see &lt;strong&gt;Kenrick &amp;amp; Crane 1997&lt;/strong&gt; for a short review). Their fossil record remains extremely gappy until the Carboniferous, basically, meaning that the first two of the &quot;Big Five&quot;, if they happened to have affected land plants, can not be observed.&lt;br&gt;&#xA;Additionally Angiosperms appeared in the early Cretaceous and diversified significantly toward the end of the Cretaceous, meaning that if the K-Pg event had an effect on the other land plants, the number of extinctions in those groups would be drowned by the number of originations in Angiosperms (I don't have any reference for that, it is just food for thought).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, land plants are not the only group that doesn't &lt;em&gt;dance to the beat&lt;/em&gt; imposed by the Big Five. For instance there is evidence that radiolarians (a group of marine heterotrophic planktonic protists with an extensive, continuous fossil record) were not affected by the K-Pg crisis (&lt;strong&gt;Hollis et al. 1995&lt;/strong&gt;) nor by the T-J event (&lt;strong&gt;Kießling &amp;amp; Danelian 2011&lt;/strong&gt;). There are still thought to have been, to some extent, affected by the P-T but there is no clear evidence (to my knowledge) for them being affected by the two previous crisis either.&lt;br&gt;&#xA;And of course there is the multitude of groups with no (or minimal) fossil record (because they have no fossilizable parts for instance and thus are only recorded in extremely rare occasions) for which we have literally no idea of what happened to them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;References:&lt;br&gt;&#xA;Hollis C., Rodgers K.A. &amp;amp; Parker R.J. 1995. &lt;a href=&quot;http://geology.gsapubs.org/content/23/9/835&quot;&gt;Siliceous plankton bloom in the earliest Tertiary of Marlborough, New Zealand&lt;/a&gt;. Geology, 23: 835-838.&lt;br&gt;&#xA;Kenrick P. &amp;amp; Crane P.R., 1997. &lt;a href=&quot;http://dx.doi.org/10.1038/37918&quot;&gt;The origin and early evolution of plants on land&lt;/a&gt;. Nature, 389: 33-39.&lt;br&gt;&#xA;Kießling W. &amp;amp; Danelian T., 2011. &lt;a href=&quot;http://dx.doi.org/10.1002/mmng.201000017&quot;&gt;Trajectories of Late Permian – Jurassic radiolarian extinction rates: no evidence for an end-Triassic mass extinction&lt;/a&gt;. Fossil Record, 14: 95-101.&lt;br&gt;&#xA;McElwain J. C. &amp;amp; Punyasena S. W., 2007. &lt;a href=&quot;http://dx.doi.org/10.1016/j.tree.2007.09.003&quot;&gt;Mass extinction events and the plant fossil record&lt;/a&gt;. Trends in Ecology &amp;amp; Evolution, 22: 548-557.&lt;br&gt;&#xA;Raup D. M. &amp;amp; Sepkoski J. J. Jr, 1982. &lt;a href=&quot;http://dx.doi.org/10.1126/science.215.4539.1501&quot;&gt;Mass Extinctions in the Marine Fossil Record&lt;/a&gt;. Science, 215: 1501-1503.&lt;br&gt;&#xA;Sepkoski J. J. Jr, 1978. &lt;a href=&quot;http://www.jstor.org/stable/2400203&quot;&gt;A kinetic model of Phanerozoic taxonomic diversity I. Analysis of marine orders.&lt;/a&gt; Paleobiology, 4: 223-251.&lt;br&gt;&#xA;Sepkoski J. J. Jr, 1979. &lt;a href=&quot;http://www.jstor.org/stable/2400257&quot;&gt;A kinetic model of Phanerozoic taxonomic diversity II. Early Phanerozoic families and multiple equilibria.&lt;/a&gt; Paleobiology, 5: 223-251.&lt;br&gt;&#xA;Sepkoski J. J. Jr, 1981. &lt;a href=&quot;http://www.es.ucsc.edu/~pkoch/EART_206/09-0120/Supplemental/Sepkoski%2081%20Pbio%207-36.pdf&quot;&gt;A factor analytic description of the Phanerozoic marine fossil record.&lt;/a&gt; Paleobiology, 7: 36-53.&lt;br&gt;&#xA;Traverse A., 1988. &lt;a href=&quot;http://www.tandfonline.com/doi/abs/10.1080/.U3m-9OvkzLg&quot;&gt;Plant evolution dances to a different beat&lt;/a&gt;. Historical Biology, 1: 277-301.&#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-05-19T12:33:14.690" LastActivityDate="2014-05-19T12:33:14.690" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="953" PostTypeId="2" ParentId="941" CreationDate="2014-05-19T08:53:25.293" Score="8" Body="&lt;p&gt;Just to add some more weight to one point of casey's excellent answer:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is no single definition of what &quot;high resolution&quot; means. Different fields, and hence different types of modelling, will have different perceptions of this. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, even within one field, the resolution that a model must have to be called &quot;high&quot; tends to increase over time as available computing power increases. For example, &lt;a href=&quot;http://cat.inist.fr/?aModele=afficheN&amp;amp;cpsidt=4559180&quot;&gt;this paper&lt;/a&gt; from 1993 describes a regional tidal model as &quot;high-resolution&quot; with a grid size of approximately 1km. Eighteen years later, &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0360544213007408&quot;&gt;this paper&lt;/a&gt; uses &quot;high resolution&quot; to describe a 50m grid (it's a nested grid, and this resolution is only in the area of interest, but the point is that the meaning of the term has changed within the same type of modelling).&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2014-05-19T08:53:25.293" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="954" PostTypeId="1" AcceptedAnswerId="2504" CreationDate="2014-05-19T13:20:42.323" Score="10" ViewCount="645" Body="&lt;p&gt;The &lt;a href=&quot;http://en.wikipedia.org/wiki/Marinoan_glaciation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Marinoan Glaciation&lt;/a&gt; (a.k.a. Elatina Glaciation) was a glaciation that is thought to have occurred towards the end of the aptly-named Cryogenian period at ca. 650Ma. It is particularly known as one of the glaciations that &lt;a href=&quot;https://earthscience.stackexchange.com/questions/346/what-would-it-take-to-confirm-or-refute-the-snowball-earth-hypothesis&quot;&gt;may or may not&lt;/a&gt; have been a Snowball Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whether or not this glaciation was truly global, there is evidence that this glaciation existed. But what are the current hypotheses on how this glaciation was triggered?&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="11908" LastEditDate="2019-03-14T01:10:49.000" LastActivityDate="2019-03-14T01:10:49.000" Title="How was the Marinoan Glaciation triggered?" Tags="|glaciology|paleoclimatology|glaciation|precambrian|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="955" PostTypeId="2" ParentId="43" CreationDate="2014-05-19T18:49:34.590" Score="18" Body="&lt;p&gt;It is true that the Gulf Stream plays a role on the different climates of each region; I would not call it an 'urban legend' as Richard Seager and other scientists put it, however it seems that how much it actually changes the climate is currently under debate.&lt;/p&gt;&#xA;&lt;p&gt;From &lt;a href=&quot;http://www.americanscientist.org/issues/issue.aspx?id=999&amp;amp;y=0&amp;amp;no=&amp;amp;content=true&amp;amp;page=5&amp;amp;css=print&quot; rel=&quot;noreferrer&quot;&gt;Wallace Broeker&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;One of the major elements of today's ocean system is a conveyor-like circulation that delivers an enormous amount of tropical heat to the northern Atlantic. During winter, this heat is released to the overlying eastward air masses, thereby greatly ameliorating winter temperatures in northern Europe.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/92rhj.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Thermohaline circulation—often dubbed &amp;quot;the ocean conveyor belt&amp;quot;—carries warm surface waters (&lt;em&gt;pink&lt;/em&gt;) from the tropics to the North Atlantic, with the return flow at depth (&lt;em&gt;purple&lt;/em&gt;). But contrary to many accounts (summarized by diagrams such as this), this heat conveyor plays only a minor role in keeping European countries warm during winter months.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It seems that although, as you stated, the Gulf Stream traditionally was thought to play a major role in the climate difference, new studies emerging shows that &lt;a href=&quot;http://www.livescience.com/13573-east-coast-colder-europe-west-coast.html&quot; rel=&quot;noreferrer&quot;&gt;only contributes a small amount&lt;/a&gt; to the temperature difference.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The cooling effect could account for 30 to 50 percent of the temperature difference across oceans, the study suggests.  It also explains why the cold region is just as big for both North America and Asia, despite the continents' differences in topography and size.&lt;/p&gt;&#xA;&lt;p&gt;The cooling depends on heating air over warm ocean water. Since the warm currents along western ocean boundaries in both the Pacific and Atlantic are similar, the resulting cold region to their west would be similar as well.  The &lt;strong&gt;new study&lt;/strong&gt; adds to other recent research that found that ocean currents such as the Gulf Stream aren't capable of transporting that much heat to northern Europe, instead contributing only up to &lt;em&gt;10 percent of their warming&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;There are also studies suggesting that the conveyor belt model itself was &lt;a href=&quot;http://www.livescience.com/8317-kinks-ocean-conveyor-belt.html&quot; rel=&quot;noreferrer&quot;&gt;extremely oversimplified&lt;/a&gt;, and its role in ocean overturning cycles is being re-evaluated:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;As the study of the modern ocean’s role in climate continues apace, the conveyor belt model no longer serves the community well — not because it is a gross oversimplification but because it ignores crucial structure and mechanics of the ocean’s intricate global overturning.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Based on the evidence at hand, I believe that the Gulf Stream &lt;em&gt;does&lt;/em&gt; play a role in making Europe warmer than North America at similar latitudes; however how large a role it plays perhaps has been overestimated, and with the new ongoing studies perhaps different climate elements, such as the &lt;a href=&quot;http://all-geo.org/highlyallochthonous/2012/06/what-do-you-mean-the-gulf-stream-doesnt-keep-europe-warm-how-even-scientists-are-afflicted-by-urban-myths/&quot; rel=&quot;noreferrer&quot;&gt;atmospheric elements&lt;/a&gt;rather than the oceanic currents, can be modeled and brought to light in the scientific community, much as Richard Seager is doing now.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The oceans do still play an important role in keeping Europe’s winters mild, but it is nothing to do with the Gulf Stream. The winds that blow northeast onto Europe from the Atlantic carry with them air that is relatively warm even in the winter; the large heat capacity of water means that the sea cools off more slowly in the winter, and this also moderates the temperature of the air above the sea surface. This contrasts with the eastern US, where the prevailing southeast winds are cold, having lost their heat to the thousands of kilometres of land surface they’ve already passed over.&lt;/p&gt;&#xA;&lt;p&gt;So the oceans are still involved, but it is the atmosphere that is the true key to explaining Europe’s mild winters; and in a pleasing geological twist, it is apparently the presence of the Rocky Mountains that causes the large scale waviness of atmospheric circulation that magnifies the temperature contrasts on either side of The Pond (Richard Seager explains this in more detail in this more comprehensive piece at the American Scientist).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="490" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-05-19T18:49:34.590" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="956" PostTypeId="2" ParentId="898" CreationDate="2014-05-20T07:57:48.120" Score="3" Body="&lt;p&gt;To answer the numerical aspect of your question: &lt;strong&gt;Rintoul &amp;amp; Wunsch 1991&lt;/strong&gt; advanced a poleward heat flux in the North Atlantic (i.e. that generated by the Gulf Stream) of $1.3\pm0.2\times 10^{15}W$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That number of 1.3 PW (PetaWatts) have been reused in several reviews on the thermohaline circulation such as &lt;strong&gt;Clark et al. 2002&lt;/strong&gt;; hinting that this number is at least realistic (since I'm not a physical oceanographer myself it is difficult for me to judge otherwise). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;References:&lt;br&gt;&#xA;Clark, P. U., Pisias, N. G., Stoecker, T. F., Weaver, A. J. 2002. &lt;a href=&quot;http://www.nature.com/nature/journal/v415/n6874/pdf/415863a.pdf&quot; rel=&quot;nofollow&quot;&gt;The role of the thermohaline circulation in abrupt climate change.&lt;/a&gt; Nature, 415: 863-869.&lt;br&gt;&#xA;Rintoul, S. R., Wunsch, C. 1991.&lt;a href=&quot;http://dx.doi.org/10.1016/S0198-0149%2812%2980017-3&quot; rel=&quot;nofollow&quot;&gt;Mass, heat, oxygen and nutrient fluxes and budgets in the North Atlantic Ocean&lt;/a&gt;. Deep Sea Research Part A, 38: S355–S377.&#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-05-20T08:02:58.737" LastActivityDate="2014-05-20T08:02:58.737" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="957" PostTypeId="1" AcceptedAnswerId="962" CreationDate="2014-05-20T09:22:27.883" Score="11" ViewCount="147" Body="&lt;p&gt;I have a suite of rocks that have nearly identical major element chemistry, but a single sample has quite different trace element concentrations. All the rocks are trachydacites. I know the analysis was done corrected. What process could cause this?&lt;img src=&quot;https://i.stack.imgur.com/8MUKf.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="500" LastEditorDisplayName="user20559" LastEditDate="2021-05-26T19:56:47.353" LastActivityDate="2021-05-26T19:56:47.353" Title="Why would a suite of related rocks have one anomalous sample?" Tags="|geology|geochemistry|petrology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="958" PostTypeId="2" ParentId="920" CreationDate="2014-05-20T10:43:46.243" Score="10" Body="&lt;p&gt;One interesting and relatively new technique is by the detection of &lt;a href=&quot;http://en.wikipedia.org/wiki/Geoneutrino&quot;&gt;geoneutrinos&lt;/a&gt;. These particles are produced by radioactive decay in the Earth's interior. They are uncommonly suitable for probing the deep Earth because -- unlike most particles and waves -- they can travel through thousands of kilometres of rock with very little absorption. Of course, this very same characteristic makes actually &lt;em&gt;detecting&lt;/em&gt; them something of a challenge, and detectors tend to be &lt;a href=&quot;http://www.e15.ph.tum.de/research_and_projects/lena/&quot;&gt;rather large&lt;/a&gt; (in the thousands of cubic metres). &lt;a href=&quot;http://www.nature.com/nature/journal/v436/n7050/abs/nature03980.html&quot;&gt;Araki et al. (2005)&lt;/a&gt; gives some early results -- but as the Wikipedia article shows, there are more and bigger detectors on the drawing boards, so we should expect to see more geoneutrino results in the coming years and decades. &lt;a href=&quot;http://scicolloq.gsfc.nasa.gov/McDonough.html&quot;&gt;This abstract&lt;/a&gt; gives the best elevator pitch I've found so far for geoneutrino research:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Radioactive decay of U and Th gives off ghost-like, neutrino particles that can be detected by 1000 ton detectors built a mile underground, where they are shielded from the cosmic rays that rain down on the Earth. Collaborations between physicists and geologists are detecting these &quot;geo-neutrinos&quot;. Future underwater detectors, deployed at different points on the ocean floor, will create a neutrino tomographic image of mantle structures sited at the base of the mantle above the core.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="94" LastActivityDate="2014-05-20T10:43:46.243" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="959" PostTypeId="1" AcceptedAnswerId="963" CreationDate="2014-05-20T11:02:33.590" Score="11" ViewCount="1721" Body="&lt;p&gt;I'm sorry if this doesn't fit &quot;Earth Science&quot; too well. No idea where else to ask this!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone help me find an accurate world map in Mercator Projection?&#xA;It doesn't need political borders or too much detail, just coastlines would do.&#xA;(Ideally with land coloured buff and sea coloured blue, but I'm not picky!)&#xA;I would be happy to pay, if it isn't too much - unless there are free resources out there!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm writing a modelling application where I need to plot Lat and Lon on a world chart so it needs to be fairly accurate (if you call Mercator Projection accurate).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for any help, and sorry if I've broken any rules here.&lt;/p&gt;&#xA;" OwnerUserId="501" LastEditorUserId="94" LastEditDate="2016-04-13T06:38:51.337" LastActivityDate="2016-04-13T06:38:51.337" Title="Where to find an accurate Mercator Projection world image?" Tags="|geography|projection|mapping|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="960" PostTypeId="2" ParentId="52" CreationDate="2014-05-20T13:04:37.200" Score="6" Body="&lt;p&gt;There is a convention for moist air entropy built from dry air entropy being 0 at T = 273.15K and P = 101325Pa, and liquid water entropy being 0 at its triple point. See the page numbered 47 of this NIST document:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nist.gov/calibrations/upload/5241.pdf&quot; rel=&quot;nofollow&quot;&gt;http://www.nist.gov/calibrations/upload/5241.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Entropy is not measured directly.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Entropy $S$ is defined as $dS \equiv dQ_{rev}/T$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, entropy can measured by measuring heat transfer and temperature. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;http://web.mit.edu/16.unified/www/SPRING/propulsion/notes/node40.html&quot; rel=&quot;nofollow&quot;&gt;Calculation of Entropy Change in Some Basic Processes&lt;/a&gt; for more information.&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2014-05-21T10:07:18.710" LastActivityDate="2014-05-21T10:07:18.710" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="961" PostTypeId="2" ParentId="959" CreationDate="2014-05-20T13:12:09.600" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;http://www.naturalearthdata.com/&quot; rel=&quot;nofollow&quot;&gt;Natural Earth is a public domain&lt;/a&gt;, map dataset available at 1:10, 1:50,&#xA;  and 1:110-million scales. Announced at the 2009 NACIS (North American&#xA;  Cartographic Information Society)annual meeting in Sacramento,&#xA;  California, the goal is to give cartographers an off-the shelf&#xA;  solution for creating small-scale world, regional, and country maps.&#xA;  It has several features of interest to mountain cartographers&#xA;  producing small-scale physical maps: rendered shaded relief images and&#xA;  GIS labels for many mountain peaks, ranges, and other physical&#xA;  features. But perhaps more importantly, it includes other reference&#xA;  themes that fit that physical geography.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Natural Earth data builds on Tom Patterson’s Physical Map of the World&#xA;  presented at the 2008 ICA Mountain Cartography Workshop, Lenk,&#xA;  Switzerland. With NACIS backing, we have launched a new website,&#xA;  naturalearthdata.com, where you can download Natural Earth and updated&#xA;  versions of Natural Earth Raster imagery of Natural Earth I and II&#xA;  raster imagery in perfect registration with vector line work. Both&#xA;  political and physical features are included in Natural Earth data.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Natural Earth solves a problem that many cartographers face: finding&#xA;  vector data for making publication-quality small-scale maps. In a time&#xA;  when the web is awash in interactive maps and free, downloadable&#xA;  vector data, such as Digital Chart of the World and VMAP, mapmakers&#xA;  are forced to spend time sifting through a confusing tangle of poorly&#xA;  attributed data. Many mapmakers working under tight project deadlines&#xA;  must use manually digitalized bases instead.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Small-scale map datasets of the world do exist, but they have their&#xA;  problems. For example, most are crudely generalized—Chile’s fjords are&#xA;  a noisy mess, the Svalbard archipelago is a coalesced blob, and Hawaii&#xA;  has disappeared into the Pacific two million years ahead of schedule.&#xA;  They contain few data layers, usually only a coast and country&#xA;  polygons, which may not be in register. The lack of good small-scale&#xA;  map data is not surprising. Large mapping organizations that release&#xA;  public domain data, such as the US Geological Survey, are not mandated&#xA;  to create small-scale map data for a small user community that&#xA;  includes mapmaking shops, publishers, web mappers, academics, and&#xA;  students—in other words, typical mountain cartographers. Natural Earth&#xA;  fills this oft-overlooked but important niche.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;(&lt;a href=&quot;http://www.mountaincartography.org/publications/papers/papers_borsa_10/12_kelso.pdf&quot; rel=&quot;nofollow&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="284" LastActivityDate="2014-05-20T13:12:09.600" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="962" PostTypeId="2" ParentId="957" CreationDate="2014-05-20T14:45:45.097" Score="6" Body="&lt;p&gt;Under the assumption that we don't know anything about &lt;strong&gt;sampling, preparation and analysis&lt;/strong&gt; we have to proceed with caution. Any of these steps can introduce effects that can produce stronger signals than the natural geochemistry of a rock sample.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just to give you an idea of the errors:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Sampling a heterogeneous rock can produce very different whole rock chemistry. If you take your sample from a mica-rich layer you will get different results than from a feldspar-rich layer.&lt;/li&gt;&#xA;&lt;li&gt;During sample preparation you can inadvertently through grinding, sieving and pouring produce aliquots which don't have the same mineral composition. Micas pour different from one vessel into another than quartz-grains. A certain mineral you want to analyze might have a smaller grain size and sit at the bottom of your vessel or in a different sieve your not analyzing. Each step in the lab can result in chemical fractioning!&lt;/li&gt;&#xA;&lt;li&gt;Analytics is a whole science on its own. Without knowing how the mineral sample was dissolved (did everything dissolve?) and values for detection limit and standard deviation you will have uncertainties in your data that might be make these values meaningless.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Now assuming that the data is somewhat trustworthy:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The left plot shows you the chondrite normalized rare earth element pattern. The light rare earths are 100 to 1000 times enriched relative to the chondrite (should actually be cited which one). Heavy earth elements are also enriched but less. The sample CCS01 has lower enrichment and a positive Eu-anomaly. This could indicate that the sample has a different mineral composition than the other samples. Maybe a rare-earth-element-enriched mineral has a lower concentration in the CCS01-sample.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The right plot the CCS01-sample sticks out again. It has lower P-concentrations. Think again of how your sample might have fewer phosphates. The relative depletion in Ce and La might correlate with P. The sample might just have less monazite (But other minerals could cause this too). Lower Nb and Ta might indicate that the sample has fewer columbite and tantalite (but the Elements occur in other minerals too).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Conclusion:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Instead of guessing you should find out everything you can about the samples history (sampling, preparation, analysis). If possible suggest more analytics. A day at the microprobe could show you which minerals are contained in your sample (rock slide or strewn grain concentrate). If not available a polarizing microscope could also help you figure out the differences in the sample (excluding very small grains).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="23" LastActivityDate="2014-05-20T14:45:45.097" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="963" PostTypeId="2" ParentId="959" CreationDate="2014-05-20T15:16:11.523" Score="13" Body="&lt;p&gt;So here is the way I do that personnally with NaturalEarth data and R (but you can do something similar i m assuming with any programming language that can deal with GIS or any GIS software):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fist download and unzip the file:&lt;/p&gt;&#xA;&#xA;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;download.file(&quot;http://www.naturalearthdata.com/http//www.naturalearthdata.com/download/10m/physical/ne_10m_coastline.zip&quot;, &quot;10m_coast.zip&quot;)&#xA;unzip(&quot;10m_coast.zip&quot;)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Then reads in the shapefile:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;library(rgdal)&#xA;library(maptools)&#xA;a &amp;lt;- readShapeSpatial(&quot;ne_10m_coastline.shp&quot;,CRS(&quot;+proj=latlon +ellps=GRS80&quot;))&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Then project it:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;a_merc &amp;lt;- spTransform(a,CRS(&quot;+proj=merc +ellps=GRS80&quot;))&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;And plot it:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;pdf(w=20,h=20,file=&quot;merc.pdf&quot;)&#xA;par(mar=c(0,0,0,0))&#xA;plot(a_merc,asp=1,xaxs=&quot;i&quot;,yaxs=&quot;i&quot;)&#xA;dev.off()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;This is a very minimalist example of course, it only draws the coastlines (as a line by opposition to drawing the continents as polygons, that would allow a more advanced colouring scheme but the projection to mercator of polygons is more complex, as Antarctica creates problems).&lt;/p&gt;&#xA;" OwnerUserId="87" LastActivityDate="2014-05-20T15:16:11.523" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="964" PostTypeId="1" CreationDate="2014-05-20T19:30:37.187" Score="11" ViewCount="119" Body="&lt;p&gt;While the Gulf Stream is a &lt;a href=&quot;http://oceanmotion.org/html/background/western-boundary-currents.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;western boundary current&lt;/a&gt; (WBC), one professor told me that the Gulf Stream is stronger than it should be just by using theoretical calculations of WBC. How much is the heat+volume flux of the Gulf Stream increased by the existence of the MOC?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="111" LastEditDate="2017-04-20T13:58:48.600" LastActivityDate="2017-04-20T13:58:48.600" Title="How much does the Meridional Overturning Circulation strengthen the Gulf Stream?" Tags="|ocean|oceanography|ocean-currents|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="965" PostTypeId="1" CreationDate="2014-05-20T21:14:19.353" Score="14" ViewCount="350" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Nereus_(underwater_vehicle)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nereus submersible&lt;/a&gt; was lost at sea while exploring the Kermadec Trench at 10,000 meters during a May 2014 research cruise. During its life, it was planned for the ROV to help investigate the evolution and diversity of life in the deepest part of the ocean, and explore how species adapt to extreme environments. With the lost of the Nereus submersible, what other resources do we have to continue deep water exploration?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Edit 20 July 2021&lt;/p&gt;&#xA;&lt;p&gt;Originally the question had a link to the Woods Hole website regarding the Nereus submersible. That link became defunct &amp;amp; was replaced by a link to Wikipedia, regarding the submersible.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="2470" LastEditDate="2021-07-20T07:09:00.307" LastActivityDate="2021-07-20T07:09:00.307" Title="What are the scientific consequences of the loss of the Nereus submersible?" Tags="|oceanography|instrumentation|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="966" PostTypeId="1" CreationDate="2014-05-21T00:37:17.883" Score="8" ViewCount="265" Body="&lt;p&gt;This is a question inspired by the post at &lt;a href=&quot;http://cliffmass.blogspot.com.au/2014/04/is-super-el-nino-coming-next-winter.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cliff Mass Weather Blog: &quot;Is a Super El Nino Coming Next Winter?&quot;&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;There is something else.  You ever hear of the Pacific Decadal&#xA;  Oscillation?  This is a cyclic phenomenon of the Pacific ocean that&#xA;  has a great impact on sea surface temperatures and other parameters. &#xA;  A graph is shown below.  We were in the warm phase from roughly 1976&#xA;  to roughly 2005 and now appear to be in a cool phase.  The strongest&#xA;  El Niños like to be in the warm phase, which is not where we are now. &#xA;  So perhaps we should be careful about predicting super El Niños.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm wondering: do we have a mechanistic explanation as for why?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="725" LastEditDate="2017-05-14T03:45:05.023" LastActivityDate="2017-05-14T03:45:05.023" Title="Why is the warm phase of the Pacific Decadal Oscillation associated with stronger El Niños?" Tags="|meteorology|ocean|climate|temperature|enso|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="967" PostTypeId="2" ParentId="965" CreationDate="2014-05-21T01:23:41.907" Score="8" Body="&lt;p&gt;Nereus as is, is currently not replaceable, but it was &lt;a href=&quot;http://www.capenews.net/falmouth/whoi_robot_implodes_in_deep-sea_trench_&quot;&gt;insured at a replacement value of $3.1 million&lt;/a&gt;, and my understanding Woods Hole currently plans to replace it, though unlikely at this point that there's a solid timeline for this taking place.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Landers, fish traps, and sediment core samplers will still be actively used, but again, these are not really comparable to the areas of research that Nereus was able to cover. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE:&lt;/strong&gt; These appears to be the &lt;a href=&quot;http://web.whoi.edu/hades/taking-stock/&quot;&gt;last log entry for the Kermadec Trench 2014 expedition&lt;/a&gt;, and the &lt;a href=&quot;http://web.whoi.edu/hades/a-sad-day/&quot;&gt;official statement on the day of the event&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="284" LastEditDate="2014-05-21T02:41:17.143" LastActivityDate="2014-05-21T02:41:17.143" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="968" PostTypeId="2" ParentId="965" CreationDate="2014-05-21T01:59:16.643" Score="7" Body="&lt;p&gt;I think the greatest impact may be upon the careers of the investigators on the project. Decades of work can be invested in the planning and building of a submersible or space probe, it an inherently risky undertaking, if it gets destroyed in the process, who takes up the job of learning from the experience and trying again? Hopefully, institutions support people through the inevitable setbacks, but sometimes not. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The instrument itself is relatively easy to replace, but the expertise to use it properly is not so easy to come by. We wish all the persons involved the best. &lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-05-21T01:59:16.643" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="969" PostTypeId="2" ParentId="920" CreationDate="2014-05-21T02:17:45.827" Score="2" Body="&lt;p&gt;Inverse problems are some of the most important mathematical problems in science and mathematics. Inverse problems arise in many branches of geophysics, medical imaging, remote sensing, ocean acoustic tomography, nondestructive testing, astronomy, physics and many other fields.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geophysicists remotely measure the seismic (acoustic), gravity, and electromagnetic fields of the earth and then treat the inverse problem to constrain the properties of the earth's interior.&lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-05-21T02:17:45.827" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="970" PostTypeId="1" AcceptedAnswerId="971" CreationDate="2014-05-21T04:06:15.267" Score="7" ViewCount="1414" Body="&lt;p&gt;I heard about the golden hour, but yesterday I saw golden and red colored patches in the sky even after sunset. Why does it happen? And I would like to know more about the science behind the golden hour.&lt;/p&gt;&#xA;" OwnerUserId="504" LastEditorUserId="87" LastEditDate="2014-11-19T15:09:33.313" LastActivityDate="2014-11-19T15:09:33.313" Title="Golden and red colored light even after sunset" Tags="|atmosphere|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="971" PostTypeId="2" ParentId="970" CreationDate="2014-05-21T04:28:12.090" Score="10" Body="&lt;p&gt;This is a result of &lt;a href=&quot;http://en.wikipedia.org/wiki/Rayleigh_scattering&quot;&gt;Rayleigh scattering&lt;/a&gt;, the same reason the sky is blue.  As the sun sets the optical path for a photon passing through the atmosphere to your eye  increases.  Because of this increased distance through the atmosphere, more scattering occurs and the shorter wavelengths are scattered away, leaving the longer wavelengths.  This results in light that is reaching your eye tending toward red and the yellow to orange and gold hues are produced on the way to red.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason you can still see this persist after sunset is because the sun below the horizon can still reach you through scattering though clouds can enhance this effect (because clouds are good at scattering all visible wavelengths and clouds you can see can be illuminated by a sun you cannot see).  This is the same principle as above, with the addition of the scattering by the cloud.  You'll have Rayleigh scattering on the way to the cloud through the atmosphere, uniform scattering off the cloud and then more Rayleigh scattering between the cloud and your eye.  The longer these distances become, the more red the light reaching your eye has become, and thus the sky will take on the reddening hue (with the yellow/orange/gold colors in the transition to red).&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-05-21T04:28:12.090" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="972" PostTypeId="1" AcceptedAnswerId="974" CreationDate="2014-05-21T10:36:30.763" Score="14" ViewCount="4240" Body="&lt;p&gt;One of the seismic inversion algorithms is called 'colored' inversion. It is performed in the frequency domain and the point is in building an operator that directly transforms a seismic trace into reflectivity trace.&lt;/p&gt;&#xA;&lt;p&gt;What does 'colored' mean and why was the specified technique named this way?&lt;/p&gt;&#xA;" OwnerUserId="506" LastEditorUserId="6129" LastEditDate="2021-12-14T04:19:09.987" LastActivityDate="2021-12-14T04:19:09.987" Title="Why is colored seismic inversion called 'colored'?" Tags="|geophysics|seismology|terminology|inversion|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="973" PostTypeId="2" ParentId="878" CreationDate="2014-05-21T12:19:44.920" Score="21" Body="&lt;p&gt;Earthquake prediction really is a contentious issue, especially after the &lt;a href=&quot;http://www.dramsch.net/archives/75-The-lAquila-trial-Getting-the-big-picture.html&quot; rel=&quot;noreferrer&quot;&gt;l'Aqula trials&lt;/a&gt;. However, let me try to elaborate how predictions might be possible in the future and what is inhibiting this development.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We do have some understanding of earthquakes and rupture mechanisms. However, for prediction in a scale of hours (sufficient for evacuation), we have to take the following into account. The stress fields in the crust are basically applying the pressure necessary for earthquakes. However, these are difficult to measure and different stresses may apply to the same region (local, regional, global stress fields). Just look at the world stress map below, how chaotic the different influences are.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Stress&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/rU0oi.gif&quot; alt=&quot;World stress map&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These stresses are also pretty difficult to measure. These methods include (Source World Stress Map):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Earthquake focal mechanisms&lt;/li&gt;&#xA;&lt;li&gt;Well bore breakouts and drilling-induced fractures&lt;/li&gt;&#xA;&lt;li&gt;In-situ stress measurements (overcoring, hydraulic fracturing, borehole slotter)&lt;/li&gt;&#xA;&lt;li&gt;Young geologic data (from fault-slip analysis and volcanic vent alignments)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;These may sometimes give contradictory &lt;a href=&quot;https://en.wikipedia.org/wiki/Cauchy_stress_tensor&quot; rel=&quot;noreferrer&quot;&gt;stress tensors&lt;/a&gt;. One of these reasons is that in-situ measurements are often more localized than focal mechanisms (as an example). But when we look at the map, we do have a lot of data (27.000 data points). Here another big problem comes into play:&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Material&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;While geophysicists like to assume that the ground is homogeneous, it really isn't. A rupture may occur when the material at a fault fails under pressure. Yet the material is highly diverse and includes cracks and fractures that make it virtually impossible to make an accurate assessment. The material may act elastic, ductile or brittle and that may be location-dependent. From this you cannot say if a small rupture triggers a larger earthquake due to &lt;a href=&quot;https://en.wikipedia.org/wiki/Coulomb_stress_transfer&quot; rel=&quot;noreferrer&quot;&gt;stress transfer&lt;/a&gt; or if it stays a small earthquake.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;What would be to improve&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;This would make a simulation highly chaotic and the prediction would have a high probability to be false positive or false negative, therefore, decreasing the reliability significantly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the end we would have to improve our understanding of:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Stress fields&lt;/li&gt;&#xA;&lt;li&gt;Stress-Strain relations&lt;/li&gt;&#xA;&lt;li&gt;Rupture mechanisms&lt;/li&gt;&#xA;&lt;li&gt;Material science and location&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h3&gt;Early Warning in California&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Nevertheless, an earthquake early warning (&lt;strong&gt;EEW&lt;/strong&gt;) system is being implemented in California (and tested). It's called &lt;a href=&quot;http://www.shakealert.org/cisn/&quot; rel=&quot;noreferrer&quot;&gt;CISN ShakeAlert&lt;/a&gt;. They can use the trick that so-called &lt;a href=&quot;https://en.wikipedia.org/wiki/P-wave&quot; rel=&quot;noreferrer&quot;&gt;P-waves&lt;/a&gt; of earthquakes are faster (and less destructive) than &lt;a href=&quot;https://en.wikipedia.org/wiki/Seismic_wave#Surface_waves&quot; rel=&quot;noreferrer&quot;&gt;surface waves&lt;/a&gt;. This can give valuable time to safety-relevant systems like nuclear plants or high speed trains. But this is in a very early stage, when an earthquake already happened and is bound to arrive somewhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(I would have loved to put down more links, but my rep is too low, so see Wikipedia for &lt;a href=&quot;https://en.wikipedia.org/wiki/Fracture_mechanics&quot; rel=&quot;noreferrer&quot;&gt;Rupture Mechanics&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Stress%E2%80%93strain_curve&quot; rel=&quot;noreferrer&quot;&gt;Stress-Strain relations&lt;/a&gt;, the &lt;a href=&quot;http://dc-app3-14.gfz-potsdam.de/pub/stress_data/stress_data_frame.html&quot; rel=&quot;noreferrer&quot;&gt;World Stress Map&lt;/a&gt; website and the CISN ShakeAlert website.)&lt;/p&gt;&#xA;" OwnerUserId="507" LastEditorUserId="115" LastEditDate="2014-05-22T13:04:54.363" LastActivityDate="2014-05-22T13:04:54.363" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="974" PostTypeId="2" ParentId="972" CreationDate="2014-05-21T16:32:49.113" Score="12" Body="&lt;p&gt;Colored inversion is designed to approximately match the average spectrum of inverted seismic data with the average spectrum observed impedance (&lt;a href=&quot;http://dx.doi.org/10.1190/1.1815711&quot; rel=&quot;noreferrer&quot;&gt;Lancaster and Whitcombe, 2000&lt;/a&gt;). The earth’s reflectivity can be considered fractal, and the resulting amplitude spectrum favors high frequencies (spectral blueing). If there was no preferred frequency, then you would have a &quot;&lt;a href=&quot;http://en.wikipedia.org/wiki/White_noise&quot; rel=&quot;noreferrer&quot;&gt;white spectrum&lt;/a&gt;&quot;, but as there are some frequencies with more energy, then it is called &quot;colored&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/t3nmx.png&quot; alt=&quot;Figure 4 from Lancaster and Whitcombe: Acoustic impedance from 4 sites in the North Sea &quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Figure 4 from Lancaster and Whitcombe: Acoustic impedance from 4 sites in the North Sea &lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-05-21T16:32:49.113" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="975" PostTypeId="1" CreationDate="2014-05-21T18:25:37.693" Score="9" ViewCount="523" Body="&lt;p&gt;What are the main geological processes that can cause local biases in the fossil record, e.g. when comparing species diversity or species occurances in different areas from the same time period? I know that there exists several &lt;a href=&quot;http://en.wikipedia.org/wiki/Fossil#Fossilization_processes&quot;&gt;processes for fossilisation&lt;/a&gt;, and that local environmental conditions are essential for fossilisation (e.g. to allow for rapid burial/sedimentation). However, my question is dealing with processes that affect a fossil record that is already formed (i.e. the period from after formation to present time). I realize that local conditions affecting the formation of fossils is probably the main reason for local biases, but am curious about processes affecting the later stages of preservation. &lt;/p&gt;&#xA;" OwnerUserId="505" LastEditorUserId="87" LastEditDate="2014-05-22T06:43:34.150" LastActivityDate="2014-08-07T12:20:06.823" Title="What geological processes can cause local biases in the fossil record?" Tags="|paleontology|fossils|taphonomy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="976" PostTypeId="2" ParentId="972" CreationDate="2014-05-21T18:57:20.320" Score="7" Body="&lt;p&gt;The answer by @aretxabaleta is dealing specifically with seismic data (which was your question). I only want to add that the &lt;a href=&quot;http://en.wikipedia.org/wiki/Colors_of_noise&quot; rel=&quot;nofollow noreferrer&quot;&gt;colour of noise&lt;/a&gt; is a general term to describe frequency spectra, that comes from electronics/physics and is used in many other fields (e.g. in &lt;a href=&quot;https://esajournals.onlinelibrary.wiley.com/doi/full/10.1890/02-3122&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;Vasseur &amp;amp; Yodzis, 2004, The color of envirnonmental noise. Ecology 85(4)&quot;&gt;colour of environmental variability&lt;/a&gt;  in ecology). White, blue, brown/red and pink are all terms that describe different frequency spectrums. White coloured noise has a flat power spectrum, brown/red noise is dominated by lower frequencies and blue noise by high frequencies. Red and blue (and pink) noise are hence named after the colour of visible light with those types of frequency spectra.&lt;/p&gt;&#xA;" OwnerUserId="505" LastEditorUserId="2470" LastEditDate="2021-12-13T21:15:58.837" LastActivityDate="2021-12-13T21:15:58.837" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="977" PostTypeId="1" AcceptedAnswerId="2218" CreationDate="2014-05-21T19:38:15.487" Score="8" ViewCount="527" Body="&lt;p&gt;I was thinking about this question, which may turn out to be simple, about climate dynamics: How does the amount of mass in an atmosphere affect the seasonal changes and dynamics of the planet's climate?  For example, while I know there are seasons on Mars, there surely isn't as stark of shift between seasons like Earth for example. Perhaps the amount of mass in the atmosphere really isn't a controlling variable? Perhaps composition or even distance to external heat sources is more important?&lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-07-04T06:51:01.533" Title="How does the amount of mass in an atmosphere affect the seasonal changes and dynamics of the planet's climate?" Tags="|meteorology|climate|planetary-science|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="978" PostTypeId="2" ParentId="620" CreationDate="2014-05-21T23:38:18.007" Score="7" Body="&lt;p&gt;The Elsevier service &lt;A href=&quot;http://www.geofacets.com/&quot;&gt;Geofacets&lt;/a&gt; &quot;is designed to search for, and extract, maps, sections and other geographically-referenced geoscientific data from a very large and growing volume of published content&quot;, and as such is perhaps relevant -- though it focusses on georeferenced data rather than on scientific articles.&lt;/p&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-05-21T23:38:18.007" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="979" PostTypeId="1" CreationDate="2014-05-22T06:36:21.883" Score="7" ViewCount="118" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;http://www.climatecentral.org/news/the-heat-is-on&quot; rel=&quot;nofollow&quot;&gt;The states that have warmed the most — whether you look at the past&#xA;  100 years or just the past 40 — include northern-tier states from&#xA;  Minnesota to Maine and the Southwest, particularly Arizona and New&#xA;  Mexico. Places that have warmed the least include Southeast states,&#xA;  like Florida, Alabama, Georgia and South Carolina, along with parts of&#xA;  the central Midwest, like Iowa and Nebraska.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Why is Arizona responding so strongly to climate change in a way that other states aren't?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="20" LastEditDate="2014-05-23T01:12:31.147" LastActivityDate="2014-11-22T04:08:39.617" Title="Why is Arizona the fastest-warming state in the U.S. (since 1970)?" Tags="|climate|climate-change|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="980" PostTypeId="1" AcceptedAnswerId="984" CreationDate="2014-05-22T08:19:45.100" Score="8" ViewCount="13908" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Zh7or.jpg&quot; alt=&quot;Wind going across the page - and changing direction&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Image Subtitle: Wind going across the page - and changing direction&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To clarify, imagine you were sat in a boat in the middle of a lake recording the wind direction every minute. You notice that the wind changes direction roughly every five minutes from 340° to 360° and back and forth...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On other days the time between and the amount (°) of wind shift can be bigger or smaller.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I presume it is something to do with the wind going over land:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;It is known that the wind is directionally deflected over land (frictional effects)&lt;/li&gt;&#xA;&lt;li&gt;Wind higher up in the atmosphere is less hindered and so less deflected&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;My guess is that the wind experienced on the lake is an alternation between these though the exact mechanics of it is beyond me. I would greatly appreciate a true explanation.&lt;/p&gt;&#xA;" OwnerUserId="512" LastActivityDate="2014-05-22T15:14:20.550" Title="Why does the wind periodically change direction?" Tags="|meteorology|geophysics|wind|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="981" PostTypeId="2" ParentId="878" CreationDate="2014-05-22T09:19:23.587" Score="6" Body="&lt;p&gt;While we have yet to produce a scientific method that reliably predicts earthquakes well in advance of their occurrence, anecdotal evidence suggests that animals can sense earthquakes before they happen.  &lt;a href=&quot;http://www.gps.caltech.edu/~jkirschvink/pdfs/earthquakeprediction.pdf&quot; rel=&quot;noreferrer&quot;&gt;Kirschvink (2000)&lt;/a&gt; suggests that the 'sixth sense' in animals is an evolutionary mechanism coined the &quot;seismic-escape response&quot;. While it is possible that some animals may be picking up on minor fluctuations in electromagnetic fields or foreshocks, there is little research to substantiate this.  However, there are studies in progress, such as the &lt;a href=&quot;http://www.economist.com/blogs/babbage/2014/02/seismology&quot; rel=&quot;noreferrer&quot;&gt;International Cooperation for Animal Research Using Space&lt;/a&gt; that may help substantiate some claims.  &lt;a href=&quot;http://www.psychologytoday.com/blog/canine-corner/201205/can-dogs-predict-earthquakes&quot; rel=&quot;noreferrer&quot;&gt;Stanley Coren&lt;/a&gt; has conducted some thought-provoking research with dogs that might point to predictive abilities.&lt;/p&gt;&#xA;" OwnerUserId="504" LastEditorUserId="510" LastEditDate="2014-05-22T14:30:06.103" LastActivityDate="2014-05-22T14:30:06.103" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="982" PostTypeId="2" ParentId="878" CreationDate="2014-05-22T12:50:02.920" Score="8" Body="&lt;p&gt;As of Spring 2014, the Oklahoma Geological Survey and the USGS generated a press release (www.okgeosurvey1.gov/media/press/Full_USGS-OGS_Statment_05022014.pdf) warning of increased seismic activity in Oklahoma.  The survey geologists observed an increase in both the occurrence and magnitude of earthquakes in the state, likely related to the increased occurrence of injecting waste water into the ground although some workers have attributed this increase to &lt;a href=&quot;http://wichita.ogs.ou.edu/documents/OGS_IS16.pdf&quot; rel=&quot;noreferrer&quot;&gt;changes in lake levels&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this case, geologists issued a warning of the potential for increased seismic activity based on the current observed trends of earthquake magnitude and occurrence.  This warning assumes that whatever factor is causing this seismicity will continue (and potentially increase).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/t3LDF.gif&quot; alt=&quot;Increase of magnitude 3.0 and greater earthquake occurrence over time&quot;&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/jwKmN.jpg&quot; alt=&quot;Seismicity in Oklahoma has been increasing over time&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="510" LastActivityDate="2014-05-22T12:50:02.920" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="983" PostTypeId="1" AcceptedAnswerId="985" CreationDate="2014-05-22T12:57:14.247" Score="16" ViewCount="574" Body="&lt;p&gt;I know that water released from oceanic crust causes melting of the mantle in subduction zones, but does any part of the subducted slab melt as well - such as the sediments on the slab or the basalt?  If so, how do we know what material was melted so deep in the subsurface?&lt;/p&gt;&#xA;" OwnerUserId="510" LastEditorUserId="32" LastEditDate="2014-05-22T17:38:37.393" LastActivityDate="2016-01-28T02:53:31.820" Title="When a tectonic plate subducts, does any of the subducted material melt, or is it just the mantle above the subducted slab that melts?" Tags="|geophysics|plate-tectonics|geodynamics|geochemistry|subduction|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="984" PostTypeId="2" ParentId="980" CreationDate="2014-05-22T15:14:20.550" Score="7" Body="&lt;p&gt;For the answer to why there is wind, see: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/541/where-does-wind-come-from/542#542&quot;&gt;Where does wind come from?&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That establishes the forces at work driving the wind, namely:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;non-linear advection of momentum&lt;/li&gt;&#xA;&lt;li&gt;the pressure gradient force (PGF)&lt;/li&gt;&#xA;&lt;li&gt;the Coriolis force &lt;/li&gt;&#xA;&lt;li&gt;friction&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Friction is less over water than over land, and so the wind will tend to flow more parallel to the isobars than they will over land at the earths surface.  The force balance between the PGF, Coriolis and friction is easy to conceptualize:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/duHxh.gif&quot; alt=&quot;Force Balance&quot;&gt;&lt;br&gt;&#xA;&lt;sub&gt;Image taken from University of Illinois at Urbana-Champaign, credits at &lt;a href=&quot;http://ww2010.atmos.uiuc.edu/(Gh)/abt/aknw/dvlp.rxml&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://ww2010.atmos.uiuc.edu/(Gh)/abt/aknw/dvlp.rxml&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this we can see that see that wind will flow with low pressure to its left, and cross the isobars slightly toward the low pressure.  The angle of the wind crossing the isobars is related to friction.  The direction of the wind is related to the orientation of the isobars and friction.  The speed of the wind is related to the spacing between isobars (close = fast, far = slow). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this only explains a steady-state wind in equilibrium, which is great for theoretical explanations but is too idealized for the real atmosphere.  In your observations on the lake, the flow is not steady-state and that pesky non-linear term is at work.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The lowest level of the atmosphere is called the boundary layer, and this extends from the surface to roughly 1 - 2 km.  During the daytime this boundary layer is &quot;well mixed&quot;, which just means it has a uniform potential temperature and moisture profile and it is turbulent.  To really over-simply turbulence, consider swirling motions of different sizes.  At the largest sizes these swirls are the size of the depth of the boundary layer.  At the smallest sizes the swirls are on the scale of millimeters, and there are swirls at all of the intermediate sizes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let us just consider the biggest of the swirls.  The top of these swirls are at the top of the boundary layer where the wind is typically faster (it can be slightly faster, or much faster).  This swirl will mix some of this momentum down to the surface, at the bottom of the swirl.  These swirls are moving around as well, not sitting in one place.  Where the swirls are, there will be a different wind velocity than where they arent, and it will depend on the orientation of the wind, the swirl and the momentum being mixed downward to the surface.  If you were standing at one place, this would give you the effect you observe, winds that change direction and/or speed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now consider all of the different sizes of eddies doing this, and things become a mess (turbulence!).  On some days the this effect is small and you might just notice subtle changes in the wind, and on other days you might have strong gusts and &quot;bumpy&quot; air.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, lets get back to the lake. The lake has a temperature flux and a momentum flux with the air above it, which produce changes in the wind.  All of this wind is moving mass around and the net result of this is that the wind is causing the pressure field to evolve, and these changes feedback into the wind.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The above effects can be rolled into the non-linear and friction terms in the momentum equation, which are the reasons that your observations of the wind periodically change directions.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-05-22T15:14:20.550" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="985" PostTypeId="2" ParentId="983" CreationDate="2014-05-22T17:38:22.033" Score="10" Body="&lt;p&gt;This is a very good question Inkenbrandt. It is quite common for even some graduate students to think that the majority of partial-melting comes from the slab: when it is the the mantle above the fore-arc, in the volcanic region, where most of the partial melting occurs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lets think about this mathematically: you say yourself that you realize that subduction hydrates the mantle, lowering the solidus and allowing for more partial melting, so what happens to the slab? Well it has to dehydrate, making it much harder to melt the slab. So to answer your question: Probably a very small amount in the upper mantle, but if you are a mantle plume believer, the partial melting of a slab provides a great mechanism to 1) displace hot mantle so it rises and 2) a source of meltable material.  The hydration of the mantle from subduction happens on a much much faster timescale than the melting of a subducted slab. In this &lt;a href=&quot;http://www.nature.com/nature/journal/v482/n7385/full/nature10749.html?WT.ec_id=NATURE-20120216&quot; rel=&quot;nofollow&quot;&gt;paper&lt;/a&gt;, the authors provide a mechanism for the volcanism in Yellowstone that relies on two things: the Farallon plate being ripped apart by rapid mantle flow and the cut off piece of the subducted slab to melt. Geochemical data supports this, and it turns out this is a very important paper.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope this answers your question. In geodynamic models interested in examining the melting structure at subduction zones, we largely ignore slab melting unless we are specifically looking at it. For almost everything else, it seems to be pretty negligible.  &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="510" LastEditDate="2016-01-28T02:53:31.820" LastActivityDate="2016-01-28T02:53:31.820" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="986" PostTypeId="1" CreationDate="2014-05-22T18:01:13.243" Score="6" ViewCount="1508" Body="&lt;p&gt;In other words... How will it affect precipitation in the tropics? The mid-latitudes? And the polar latitudes?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm interested in both the mean and variance of the precipitation.&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="56" LastEditDate="2014-07-02T10:40:04.480" LastActivityDate="2014-07-25T04:15:39.230" Title="How will climate change affect the latitudinal distribution of precipitation over each latitudinal region?" Tags="|atmosphere|precipitation|climate-change|global-warming|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="987" PostTypeId="1" AcceptedAnswerId="2274" CreationDate="2014-05-22T18:07:24.613" Score="5" ViewCount="118" Body="&lt;p&gt;They can be seen in the diagram below (of the CERES radiation dataset - supposedly they contribute a lot to the total variance in net radiation, which is the sum of SW and LW) - just west of Peru and Mexico (my supervisor, Dargan Frierson, said these are stratocumulus regions). I'm just wondering - why are stratocumulus clouds so abundant there?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(the diagram is taken after taking the 12-month running mean of the dataset, which smoothes out a lot of features).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/wguOB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="10" LastActivityDate="2014-07-17T19:57:27.913" Title="Why is the eastern Pacific full of stratocumulus clouds, and why do they have so much variation in net radiation?" Tags="|atmosphere|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="988" PostTypeId="2" ParentId="965" CreationDate="2014-05-22T18:46:18.097" Score="5" Body="&lt;p&gt;In the latest &lt;a href=&quot;http://sites.agu.org/eos-whoi/&quot; rel=&quot;nofollow noreferrer&quot;&gt;EOS number&lt;/a&gt; there is an interview with Woods Hole Oceanographic Institution's scientist Timothy Shank in which he responds to the question. It seems that we are back to just snapshots and grad samples of the hadal ecosystem.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Eos: What research opportunities have been lost as a result of the loss of Nereus?&lt;/p&gt;&#xA;&lt;p&gt;Shank: The ability of Nereus to do directed surveys and sample collection is critical for hadal research. Without it, we will be limited to the snapshot views of static instruments that only provide a limited perspective on what is an exceedingly complex ecosystem.&lt;/p&gt;&#xA;&lt;p&gt;Eos: How much of the science that was planned to be done with Nereus can be done with other methods?&lt;/p&gt;&#xA;&lt;p&gt;Shank: The capabilities Nereus provided were unique. We will be forced to rely on chance to retrieve sediment samples or macro fauna. Some things are simply not possible—such as near-bottom camera surveys or non-scavenging macro faunal recovery. The big-picture questions that will be affected include how much carbon is being sequestered in hadal sediments, how hadal ecosystems are structured, how human activity is affecting the lower one-third of the ocean’s depth, how much of what type of food is available to life in the deep ocean, and the range of adaptations life has evolved to cope with conditions in the deep ocean. Many of these are fundamental, first-order questions that we are only beginning to address.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="111" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-05-22T18:46:18.097" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="989" PostTypeId="1" CreationDate="2014-05-22T23:30:46.527" Score="12" ViewCount="739" Body="&lt;p&gt;&lt;a href=&quot;https://solarsystem.nasa.gov/scitech/display.cfm?ST_ID=1149&quot;&gt;It is thought&lt;/a&gt; that &quot;deep&quot; moonquakes are caused by tidal forces exerted on the Moon by the Earth and Sun. Some other sorts of moonquakes are thought to be caused by impacts, or by thermal expansion (when part of the moon rotates into sunlight). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, there is another type of moonquake that occurs just 20-30 kilometers below the surface. Do we know why these quakes occur? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The article I linked above suggests that the cause is currently unknown, but that article is a few years old and is just a popular news article. As I am not familiar with the literature on this topic, I would like to know if there are any well-substantiated hypotheses about the cause of shallow moonquakes that have been put forth. &lt;/p&gt;&#xA;" OwnerUserId="67" LastEditorUserId="67" LastEditDate="2014-05-22T23:37:33.603" LastActivityDate="2014-10-11T12:08:23.713" Title="What causes &quot;shallow&quot; moonquakes?" Tags="|seismology|planetary-science|moon|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="990" PostTypeId="1" CreationDate="2014-05-23T01:38:28.917" Score="19" ViewCount="1490" Body="&lt;p&gt;Today, 70.8% of the Earth is covered in water (± a few tenths of a percent depending on how you account for lakes).&lt;a href=&quot;http://www.physicalgeography.net/fundamentals/8o.html&quot;&gt;&lt;sup&gt;1&lt;/sup&gt;&lt;/a&gt; How has this figure changed over the history of the Earth, and why?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, if we go back to the early Hadean Eon, there were no oceans at all, so obviously there was an upward trend, at least initially - but what was the nature of that upward trend? And, once the oceans were more or less &quot;done&quot; forming, was the fraction of Earth covered by water reasonably constant, or not?&lt;/p&gt;&#xA;" OwnerUserId="67" LastEditorUserId="11908" LastEditDate="2019-03-17T19:43:18.430" LastActivityDate="2019-03-17T19:43:18.430" Title="Historically, how has the fraction of Earth covered by water changed?" Tags="|oceanography|plate-tectonics|earth-history|sea-level|paleogeography|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="991" PostTypeId="1" AcceptedAnswerId="993" CreationDate="2014-05-23T05:05:34.907" Score="11" ViewCount="482" Body="&lt;p&gt;Water on earth has been theorized to have come through comets trapped inside crystals. But why wouldn't that water evaporate on impact, and wouldn't the atmosphere at that time allow the vapours to escape Earth?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, what is the current scientific opinion of the validity of this theory ?&lt;/p&gt;&#xA;" OwnerUserId="516" LastEditorUserId="725" LastEditDate="2014-11-20T14:01:51.820" LastActivityDate="2014-11-20T14:01:51.820" Title="Regarding the theory of the origin of water on Earth through meteorites, why wouldn't the water evaporate on impact?" Tags="|earth-history|meteorite|planetary-formation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="992" PostTypeId="1" AcceptedAnswerId="1004" CreationDate="2014-05-23T06:22:07.763" Score="35" ViewCount="5489" Body="&lt;p&gt;We know (think?) that Earth has three Hadley cells per hemisphere, but from observing gas giants such as Jupiter, we see that they have many more cells. According to a link from a comment in &lt;a href=&quot;https://earthscience.stackexchange.com/questions/388/why-does-the-hadley-cell-descend-at-30-degrees&quot;&gt;this question&lt;/a&gt;, &lt;a href=&quot;http://saturn.jpl.nasa.gov/news/cassinifeatures/feature20070601f/&quot; rel=&quot;noreferrer&quot;&gt;Titan might have one cell going from north to south poles&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What factors affect the number of cells a planet has, and how? Or to put it another way, given a hypothetical planet with atmosphere, what facts would you need to know in order to guess at how many cells it has?&lt;/p&gt;&#xA;" OwnerUserId="85" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2021-08-16T21:19:20.370" Title="What factors determine the number of Hadley cells for a planet?" Tags="|meteorology|planetary-science|atmospheric-circulation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="993" PostTypeId="2" ParentId="991" CreationDate="2014-05-23T12:26:00.410" Score="10" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;why wouldn't that water evaporate on impact, and wouldn't the atmosphere at that time allow the vapours to escape Earth?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The water would very likely evaporate on impact.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, gravity would prevent the gas phase water molecules from leaving Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The speed of a water molecule must be compared to the &lt;a href=&quot;http://en.wikipedia.org/wiki/Escape_velocity&quot;&gt;escape velocity&lt;/a&gt; of Earth (11 km/s) to determine whether or not the molecule can escape.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At a given temperature, the velocity of water molecules will be governed by a &lt;a href=&quot;http://en.wikipedia.org/wiki/Maxwell_distribution&quot;&gt;Boltzmann distribution&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most probable velocity of a molecule will be:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$V= \sqrt{\frac{2kT}{m}}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $m$ is the mass of the molecule and $k$ is Boltzmann's constant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, at a temperature of 300 K, a water molecule will have a most probable velocity of 520 m/s, about a factor of 20 below the escape velocity. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;what is the current scientific opinion of the validity of this theory?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Comets have a higher fraction of deuterium in their water compared to Earth.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;http://neo.jpl.nasa.gov/news/news008.html&quot;&gt;&quot;Earth's water probably didn't come from comets, Caltech researchers say&quot;&lt;/a&gt;, this refutes the hypothesis that a large fraction of Earth's water came from comets.&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="67" LastEditDate="2014-05-24T00:32:52.443" LastActivityDate="2014-05-24T00:32:52.443" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="994" PostTypeId="1" AcceptedAnswerId="1000" CreationDate="2014-05-23T15:37:03.213" Score="15" ViewCount="1648" Body="&lt;p&gt;If I release a say, one litre of gas, at a particular point on the planet, how soon, on average, would it take to be distributed evenly (mixed) across the entire earth's atmosphere?&lt;/p&gt;&#xA;" OwnerUserId="519" LastEditorUserId="174" LastEditDate="2014-05-29T07:45:16.770" LastActivityDate="2014-05-29T07:45:16.770" Title="How long does it take for the atmosphere to mix?" Tags="|meteorology|climate|atmospheric-circulation|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="996" PostTypeId="1" CreationDate="2014-05-24T01:52:01.580" Score="23" ViewCount="490" Body="&lt;p&gt;The Earth exhibits plate tectonics, but the other terrestrial planets do not (though Mars and Venus may have exhibited plate tectonics in the past). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is &quot;special&quot; about Earth that allows it to have plate tectonics? Equivalently, what conditions are necessary for a rocky body to have plate-tectonic activity? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(I assume that papers like (1) and (2) are good surveys of the topic, but I lack the background to synthesize the information in these papers into a good answer.)&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;(1)&lt;/sup&gt; Paula Martin &lt;em&gt;et al&lt;/em&gt; 2008 &lt;em&gt;Phys. Educ.&lt;/em&gt; &lt;b&gt;43&lt;/b&gt; 144 &lt;a href=&quot;http://dx.doi.org/10.1088/0031-9120/43/2/002&quot;&gt;doi:10.1088/0031-9120/43/2/002&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;(2)&lt;/sup&gt; C. O'Neill &lt;em&gt;et al&lt;/em&gt; 2007 &lt;em&gt;Earth and Planetary Science Letters&lt;/em&gt; &lt;strong&gt;261&lt;/strong&gt; 1-2 &lt;a href=&quot;http://dx.doi.org/10.1016/j.epsl.2007.05.038&quot;&gt;doi:10.1016/j.epsl.2007.05.038&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="67" LastActivityDate="2014-10-20T10:42:27.080" Title="What properties must a rocky body possess in order to exhibit plate tectonics?" Tags="|geophysics|plate-tectonics|planetary-science|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="997" PostTypeId="2" ParentId="896" CreationDate="2014-05-24T05:52:52.503" Score="4" Body="&lt;p&gt;The short answer is 'yes'. Earth's response to climate change is closely coupled to the deep ocean's uptake of heat and $\ce{CO2}$; the ocean is by far the biggest sink for excess heat (~90% of the excess heat absorbed by the planet goes into the ocean, the rest largely goes towards melting ice sheets/glaciers).&#xA;The ocean is also a major sink for carbon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How effective the ocean is at absorbing heat/$\ce{CO2}$ is closely tied to rates of deep water formation, that is the densification of near surface ocean water by surface fluxes like cooling and evaporation, which then sinks and doesn't come back to the surface for centuries or even millennia. The major deep water formation regions are the Southern Ocean and the North Atlantic. The sinking of North Atlantic Deep Water (NADW) is the northern part of the 'Atlantic Conveyor' (the term sometimes colloquially used to describe the AMOC).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A slowdown in the AMOC, therefore, wouldn't just impact regional climates in N. America and Western Europe, but would also reduce the deep ocean's uptake of heat and $\ce{CO2}$, and by consequence cause a greater increase in surface temperatures.&lt;/p&gt;&#xA;" OwnerUserId="344" LastEditorDisplayName="user889" LastEditDate="2014-12-23T03:14:24.377" LastActivityDate="2014-12-23T03:14:24.377" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="998" PostTypeId="2" ParentId="990" CreationDate="2014-05-24T13:35:23.773" Score="11" Body="&lt;p&gt;Can't say much about the later epochs, but the 'hellish Hadean' epoch without oceans is kind of an outdated idea.&lt;br&gt;&#xA;We have &lt;a href=&quot;http://en.wikipedia.org/wiki/Zircon&quot;&gt;zircon&lt;/a&gt; records &lt;a href=&quot;http://www.nature.com/nature/journal/v409/n6817/full/409175A0.html&quot;&gt;indicating&lt;/a&gt; that crust and oceanic formation was already done to some unknown extent 4.4 Gyrs ago. The zircon analyzed in the nature paper given originates from interaction with sub-crustal material in a watery environment at this date.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2014-05-24T13:35:23.773" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1000" PostTypeId="2" ParentId="994" CreationDate="2014-05-24T20:36:16.077" Score="11" Body="&lt;p&gt;The time scale of interhemispheric tropospheric transport is in the order of one year (Chapter 4 of the book &lt;a href=&quot;http://acmg.seas.harvard.edu/publications/jacobbook/index.html&quot;&gt;Introduction to Atmospheric Chemistry&lt;/a&gt; written by Daniel J Jacob). This is not an exact answer to your question, but might be a fair enough number for the problem you have in mind.&lt;/p&gt;&#xA;" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2014-05-24T21:08:55.287" LastActivityDate="2014-05-24T21:08:55.287" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="1001" PostTypeId="1" AcceptedAnswerId="1003" CreationDate="2014-05-25T00:06:53.493" Score="17" ViewCount="471" Body="&lt;p&gt;My understanding is that the dominant factor behind the slowing of the Earth's rotation (i.e. the lengthening of the day) is tidal friction induced by the Moon's gravity. As seen on the graph below, the general trend is towards slower rotation of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/File:Leapsecond.ut1-utc.svg&quot; rel=&quot;noreferrer&quot; title=&quot;&amp;quot;File:Leapsecond.ut1-utc.svg&amp;quot; at Wikipedia&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Sb6yu.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Plot showing the difference UT1−UTC in seconds. Vertical segments correspond to leap seconds. Red part of graph was prediction (future values) at the time the file was made.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However! There are a few cases where the rotation of the Earth appears to have become &lt;em&gt;faster&lt;/em&gt;, most noticeably in the 2003-04 and 2004-05 segments. What is the underlying cause of these and other temporary increases in the Earth's rate of rotation? (I'm asking this in a general sense, though I would also be interested to know what events any of the specific upswings on the graph correspond to.)&lt;/p&gt;&#xA;" OwnerUserId="67" LastActivityDate="2014-08-14T04:24:56.677" Title="What geophysical events can (temporarily) increase the Earth's rate of rotation?" Tags="|geophysics|earth-rotation|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1002" PostTypeId="2" ParentId="573" CreationDate="2014-05-25T02:15:09.170" Score="3" Body="&lt;p&gt;Tornado alley exists because warm moist air from the Gulf of Mexico collides with cool dry air from over the Rocky mountains, this causes instability in the atmosphere. These two ingredients meet directly over the Midwest and plains. This results in rotation and then the rest is... Well, for those of us living in tornado alley, we hear tornado sirens &lt;em&gt;far&lt;/em&gt; to frequently. (Other tornadoes that occur down south can be caused by this or hurricanes). &#xA;&lt;a href=&quot;http://en.wikipedia.org/wiki/File%3aTornado_Alley_Diagram.svg&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/File:Tornado_Alley_Diagram.svg&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="342" LastActivityDate="2014-05-25T02:15:09.170" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1003" PostTypeId="2" ParentId="1001" CreationDate="2014-05-25T05:47:05.543" Score="19" Body="&lt;h2&gt;TL;DR&lt;/h2&gt;&#xA;&lt;p&gt;The Earth's rotational angular momentum is indeed being transferred to the Moon's orbit. However, this is a very slow process that is barely noticeable even over the course of hundreds of years. That long-term trend is invisible in the short thirty year span shown in the graph in the question. The variations seen in the plot result from transfer of angular momentum amongst components of the Earth (solid Earth, the atmosphere, the oceans, and the outer and inner core) and from changes in the Earth's inertia tensor.&lt;/p&gt;&#xA;&lt;h2&gt;About the Graph in the Question&lt;/h2&gt;&#xA;&lt;p&gt;Regarding that graph, what you are seeing are&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The cumulative effect of transfer of angular momentum to the Moon since the early 1800s, and&lt;/li&gt;&#xA;&lt;li&gt;Short-term effects that have nothing to do with that long-term trend.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Regarding the first item, our 86,400 seconds per day is based on the length of day in about 1821. The CGS second was defined in the late 1800s based on data collected over a ~100 year period, centered around 1821. The SI second is now based on atomic clocks, but the definition was intentionally made consistent with that old CGS second. The length of day has increased by about 2 milliseconds since the early 1800s.&lt;/p&gt;&#xA;&lt;p&gt;Suppose the Earth's rotation rate held steady at one mean solar day per 86,400.002 seconds, the average rotation rate over the last several decades. We would still need to add a leap second every 500 days or so because of that 2 milliseconds increase in the length of day. That's the primary feature you are seeing in the plot shown in the question.&lt;/p&gt;&#xA;&lt;p&gt;Regarding the second item, the variations during the 30 year span in that plot don't have much to do with the variation over the 200 year span since the early 1800s, and those in turn don't have much to do with the very, very long term variations in length of day due to transfer of angular momentum to the Moon. That very, very long  term trend becomes obvious only over the course of many tens of thousands of years or more. Over the short term (a hundred years is &amp;quot;short term&amp;quot; in this sense), various cyclical effects dominate over this very long term trend. The transfer of angular momentum to the Moon is completely hidden in the 30 year span covered in the plot shown in the question. That's just too short a time span to see that transfer of angular momentum.&lt;/p&gt;&#xA;&lt;p&gt;So what is that plot showing? The two most notable features are the long stretch between 1900 and 1998 with almost yearly leap second adjustments and the long stretch between 1999 and 2006 with no leap second adjustments.&lt;/p&gt;&#xA;&lt;h2&gt;Short-term Variations in Length of Day&lt;/h2&gt;&#xA;&lt;p&gt;Those leap second adjustments make it a bit hard to see what's going on. Here's a much better portrayal:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://hpiers.obspm.fr/eop-pc/earthor/ut1lod/lod_elfil.gif&quot; alt=&quot;&quot; /&gt;&#xA;Source: &lt;a href=&quot;https://hpiers.obspm.fr/eop-pc/earthor/ut1lod/UT1.html_nov08&quot; rel=&quot;noreferrer&quot;&gt;https://hpiers.obspm.fr/eop-pc/earthor/ut1lod/UT1.html_nov08&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The first thing you should look at in the above plot is the top curve. This is LOD, length of day (better: excess length of day). The length of a day is 86400 seconds and a tiny bit more. LOD is defined to be just that tiny bit more. LOD decreased between 1973 to 1987 and then again between 1993 to 2004. The Earth's rotation rate was very slightly increasing during those intervals.&lt;/p&gt;&#xA;&lt;p&gt;As mentioned above, angular momentum is being transferred from the Earth to the Moon, but this is a very slow process. What this means is that the Earth's total angular momentum is very nearly constant over the span of years, even decades. Note that it's angular momentum, not angular velocity that is the nearly conserved quantity. Angular velocity can change while angular momentum remains constant. The graph above depicts change in period, and hence change in angular velocity.&lt;/p&gt;&#xA;&lt;p&gt;The Earth comprises five different rotating systems: The inner core, the outer core, the mantle and crust, the oceans, and the atmosphere. Our terrestrial timescales, UT1 and UTC, are based on the rotation of the mantle and crust only. These five systems do not quite rotate in unison. For example, the inner core is currently rotating slightly faster than one revolution per day while the outer core is rotating slightly slower than one revolution per day. These systems transfer angular momentum amongst themselves.&lt;/p&gt;&#xA;&lt;p&gt;Some of this transfer is visible in the &amp;quot;Seasonal Variations&amp;quot; plot in the above graph. The mantle and crust transfer angular momentum to and from the oceans and atmosphere on a seasonal basis. What's left after removing those season variations and other high frequency variations (shown as &amp;quot;Irregular Variations&amp;quot; in the above graph) is the white &amp;quot;Trend&amp;quot; line overlaid on top of the blue plot. This white curve shows multi-year variations in the length of day.&lt;/p&gt;&#xA;&lt;h2&gt;Summary&lt;/h2&gt;&#xA;&lt;p&gt;The trend over hundreds of millennia a very gradual increase in length of day due to transfer of angular momentum from the Earth's rotation to the Moon's orbit about the Earth, currently about 2.3 milliseconds per day per century. That's not visible in the plot shown in the question. Over the past several millennia, post-glacial rebound has exchanged less dense ice/water in the polar regions with more dense rock. This reduced the Earth's moment of inertia and thus increased the Earth's rotation rate. Over decades, variations in length of day largely due to interactions between the core and mantle. The inter-annual variations are due to transfers of angular momentum amongst the core, mantle, oceans, and atmosphere. The El Niño–Southern Oscillation and changes in the gravitational field are key drivers in these inter-annual variations.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-08-06T15:16:34.560" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="1004" PostTypeId="2" ParentId="992" CreationDate="2014-05-25T14:38:14.720" Score="21" Body="&lt;p&gt;Well for one, this will surely be the speed of planetary rotation and the wind speeds your atmosphere can generate in North-South-direction.&lt;br /&gt;&#xA;In my understanding those cells form as N-S winds flow and become deflected from this direction. So the number of cells will be determined by the winds that start either at the equator or the pole and the distance that they can cover before being deflected into completely zonal direction.&lt;/p&gt;&#xA;&lt;p&gt;To have a rough idea about this distance I tried to estimate this (in a very quick, dirty and most likely extremely wrong way) by assuming the simplified Navier-Stokes equation in planetary coordinates on synoptic scales:&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\partial_t \vec v = 2 \Omega \sin\Theta (\vec v \times \vec z),$$&lt;/span&gt;&lt;br /&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$\Theta$&lt;/span&gt; is the planetary latitude, &lt;span class=&quot;math-container&quot;&gt;$\Omega=\Omega(\Theta)$&lt;/span&gt; the local planetary rotation frequency at the given latitude and &lt;span class=&quot;math-container&quot;&gt;$v_0$&lt;/span&gt; the local wind speed, leading to a harmonic equation for the meridional speed&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\partial_{tt} v_{\phi} = -(2\Omega \sin\Theta)^2 v_{\phi},$$&lt;/span&gt;&#xA;which with the usual arguments of scale-analysis gives us a timescale &lt;span class=&quot;math-container&quot;&gt;$\tau_{\phi}$&lt;/span&gt; for the periodic movement involved in solutions of that equation, of&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\tau_{\phi} \sim \frac{1}{2\Omega \sin\Theta}$$&lt;/span&gt;&lt;br /&gt;&#xA;corresponding to a distance&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ d \sim \frac{v_0}{2\Omega \sin\Theta_0}$$&lt;/span&gt;&#xA;covered by the vortex. Of course, I cheated here by assuming the initial speed &lt;span class=&quot;math-container&quot;&gt;$v_0 = \text{const}$&lt;/span&gt; and the initial Coriolis-factor constant with &lt;span class=&quot;math-container&quot;&gt;$\Theta = \Theta_0$&lt;/span&gt;.&lt;br /&gt;&#xA;As now such a &amp;quot;structure&amp;quot; (solution of the above eqs.) will have a size of &lt;span class=&quot;math-container&quot;&gt;$2d$&lt;/span&gt; in the meridional direction, having space of &lt;span class=&quot;math-container&quot;&gt;$\pi R_{\text{planet}}$&lt;/span&gt; our number of Hadley cells per hemisphere becomes simply&#xA;&lt;span class=&quot;math-container&quot;&gt;$$N = \frac{\pi R_{\text{planet}} \Omega \sin\Theta_0}{v_0}$$&lt;/span&gt;&lt;br /&gt;&#xA;Where we'd need to estimate this number starting at the poles, as the Coriolis-parameter vanishes at the equator.&lt;/p&gt;&#xA;&lt;p&gt;I will later (if I don't forget it) pluck in some numbers and see how bad this estimate is, or perhaps someone can try that. Anyway, I'm open for improvements of those arguments from anyone who knows something, but a quick look into Holton, &lt;em&gt;An Introduction to Dynamic Meteorology&lt;/em&gt;, unfortunately didn't reveal much.&lt;/p&gt;&#xA;&lt;p&gt;But to also address your question a little bit further: Of course, we'd need to have some climatic model to be able to estimate &lt;span class=&quot;math-container&quot;&gt;$v_0$&lt;/span&gt; and know the speed of planetary rotation. Independent of how bad my formula is, the initial arguments of deflection vs. 'climbing the meridian' should hold for the formation of a Hadley cell.&lt;br /&gt;&#xA;Returning winds from higher atmospheric layers, surface friction in the atmospheric boundary layer will also play a role for an exact calculation.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Addendum: &lt;a href=&quot;http://journals.cambridge.org/action/displayAbstract?fromPage=online&amp;amp;aid=373502&amp;amp;fileId=S0022112075001504&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rhines (1975)&lt;/a&gt; has however found a relation &lt;span class=&quot;math-container&quot;&gt;$N \sim R_{planet} \sqrt{\frac{\Omega}{v_0}}$&lt;/span&gt;, by considering how turbulent eddies will break up energy-limited by zonal jets. Also turbulent eddies can provide a good mechanism for justifying a locally constant &lt;span class=&quot;math-container&quot;&gt;$v_0$&lt;/span&gt;, that I simply assumed in my calculation above.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand I just noticed a trivial error in my above calculation and cleared that. The fraction that is N was the other way round. Sorry for that.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;I wanted to note one other thing that seems important to me (and is perhaps also to anyone on this planet..):&lt;br /&gt;&#xA;While this rule of thumb-calculations can work out, there is more physics that play a role in shaping the exact morphology of circulation-cells on a planet. Namely the radiative equilibrium in the atmosphere, which links the exact positions of those cells to a changing climate.&lt;/p&gt;&#xA;&lt;p&gt;As a &lt;a href=&quot;http://www.nature.com/ngeo/journal/v1/n1/full/ngeo.2007.38.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;study&lt;/a&gt; suggests by measuring Tropical to Polar-Jet distances and Tropopause heights, those cells can expand and reshape the environment people live in.&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="489" LastEditDate="2021-08-16T21:19:20.370" LastActivityDate="2021-08-16T21:19:20.370" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="1005" PostTypeId="1" CreationDate="2014-05-25T14:48:28.547" Score="1" ViewCount="622" Body="&lt;p&gt;I want to make precipitation data analysis for the Latvian territory.&#xA;I only have meteorological stations and reanalysis  data. &#xA;My data from meteorological stations are in the format:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;year  month  day    time      station1 station2 station3&#xA;2013    1     1    03.00        0                 0.1&#xA;2013    1     1    06.00        0.1               0.2&#xA;2013    1     1    15.00        0       0.1         0&#xA;2013    1     1    18.00        0.2     0         0.3&#xA;2013    1     2     03.00        0                 0.4&#xA;                  ...  &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;I also have a file with coordinates for meteorological stations.&#xA;And data from reanalysis is in format &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;&amp;gt; head(data)&#xA;  longitude latitude   time value&#xA;1     -27.0      -27 990555     0&#xA;2     -25.5      -27 990555     0&#xA;3     -24.0      -27 990555     0&#xA;4     -22.5      -27 990555     0&#xA;5     -21.0      -27 990555     0&#xA;6     -19.5      -27 990555     0&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Edited: My main questions are:&#xA;1) What can tell me if these data are similar, should I look their summary and compare, or it is better to use some tests. Could you advice methods how to compare different data.&#xA;2) If there are missing values, should I just get them out and then analyse data?&lt;br&gt;&#xA;3) Maybe someone can advice some tutorial with R code? Can someone tell me how to decode time values from format like 990555 (I need formula or function for R)?&lt;/p&gt;&#xA;" OwnerUserId="523" LastEditorUserId="523" LastEditDate="2014-05-28T15:51:52.137" LastActivityDate="2014-05-28T15:51:52.137" Title="How to perform precipitation data analysis?" Tags="|meteorology|precipitation|data-formats|" AnswerCount="1" CommentCount="2" ClosedDate="2014-05-28T13:17:21.320" ContentLicense="CC BY-SA 3.0" />
  <row Id="1007" PostTypeId="1" CreationDate="2014-05-25T20:53:15.957" Score="6" ViewCount="445" Body="&lt;p&gt;The Younger Dryas was associated with less heat transport from the Southern Hemisphere to the Northern Hemisphere (and a lower flux of the meridional overturning circulation).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I'm wondering - what were the temperatures of the SH like during that period?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="87" LastEditDate="2014-10-22T07:48:23.527" LastActivityDate="2014-12-03T04:43:46.173" Title="Was the Southern Hemisphere cooler during the Younger Dryas?" Tags="|climate|younger-dryas|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1008" PostTypeId="1" CreationDate="2014-05-25T20:58:45.583" Score="8" ViewCount="249" Body="&lt;p&gt;Or in other words, does it increase the amount of heat+moisture advection from the Gulf of Mexico into the Central United States? And is this increase associated with increased CAPE/tornado/thunderstorm activity?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="111" LastEditDate="2014-12-21T21:51:13.600" LastActivityDate="2014-12-21T21:51:13.600" Title="How does El Niño affect thunderstorm/tornado/CAPE activity in the central United States?" Tags="|meteorology|atmosphere|enso|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="1009" PostTypeId="1" CreationDate="2014-05-25T21:05:21.497" Score="7" ViewCount="94" Body="&lt;p&gt;And how much does this heat compare with the total fraction of heat otherwise transported from equatorial to polar latitudes, and from ocean to atmosphere?&lt;/p&gt;&#xA;" OwnerUserId="10" LastActivityDate="2014-05-25T21:05:21.497" Title="How much heat do hurricanes transport from equatorial to more polar latitudes, and from ocean to atmosphere?" Tags="|atmosphere|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1011" PostTypeId="1" AcceptedAnswerId="1016" CreationDate="2014-05-25T21:08:45.480" Score="5" ViewCount="725" Body="&lt;p&gt;Or in other words, can they be seen as sources of heat transport?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If so, what can be thought of as the heat source, and what can be thought of as the heat sink?&lt;/p&gt;&#xA;" OwnerUserId="10" LastActivityDate="2014-05-26T08:01:30.147" Title="Can thunderstorms be thought of as a heat engine?" Tags="|atmosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1013" PostTypeId="1" CreationDate="2014-05-25T21:13:44.987" Score="2" ViewCount="125" Body="&lt;p&gt;This is a field in the &lt;a href=&quot;http://data-portal.ecmwf.int/data/d/interim_daily/&quot; rel=&quot;nofollow&quot;&gt;ERA-Interim&lt;/a&gt; dataset. What is its significance, and what is it important for?&lt;/p&gt;&#xA;" OwnerUserId="10" LastActivityDate="2014-05-25T21:13:44.987" Title="What is the significance of the Vertical integral of northward kinetic energy flux?" Tags="|atmosphere|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="1014" PostTypeId="1" CreationDate="2014-05-25T21:31:52.970" Score="4" ViewCount="91" Body="&lt;p&gt;Is there a higher number of mid-latitude high/low pressure regions at 850 mb, as compared to the number of high/low pressure regions at 200 mb?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And if so, why?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="64" LastEditDate="2014-12-21T01:58:26.070" LastActivityDate="2014-12-21T01:58:26.070" Title="Is the number of high/low pressure regions different at low pressure levels at high pressure levels?" Tags="|meteorology|atmosphere|atmosphere-modelling|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1015" PostTypeId="1" AcceptedAnswerId="1018" CreationDate="2014-05-26T06:46:53.150" Score="7" ViewCount="18786" Body="&lt;p&gt;They say you can't pack objects like pentagons or octagons such that they fill up space entirely and that that's one reason there is no 5-fold or 8-fold rotational axis. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are you telling me you can fill up space stacking dodecahedrons or hexakis octahedrons? I don't think so. Please explain this to me. I thought that crystals are built by stacking unit cells on one another. &lt;/p&gt;&#xA;" OwnerUserId="521" LastEditorUserId="67" LastEditDate="2014-05-27T00:57:13.150" LastActivityDate="2018-06-17T15:40:41.927" Title="Why are there no crystals with 5-fold symmetry?" Tags="|crystals|crystallography|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="1016" PostTypeId="2" ParentId="1011" CreationDate="2014-05-26T08:01:30.147" Score="7" Body="&lt;p&gt;Yes, they can.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Broadly speaking, most dynamical atmospheric phenomena are heat engines in one form or another. Ultimately the heat source is due to sunlight heating up the ground, and the cold sink is the upper atmosphere, which stays cold due to emitting thermal radiation into space. Large convection cells (such as tropical cyclones or the Hadley cells) act broadly like Carnot engines, adiabatically expanding packets of air as they're brought upwards from the ground to the upper atmosphere, then isothermally compressing them as they radiate into space, then adiabatically compressing them as they travel back down to the surface, and then isothermally expanding them as they pick up heat from the ground. (This description is a very rough approximation to the reality.) The net effect is to transfer heat from the ground to the upper atmosphere, while converting a small amount of that heat into kinetic energy, which keeps the whole thing moving.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thunderstorms are quite an interesting case, because they are driven by latent heat as well as sensible heat. The air near the surface is not just warm but moist, due to evaporation and evapotranspiration from plants. As air rises it cools. Cool air can hold less moisture than warm air, so this can lead to condensation (i.e. the formation of clouds and rain). This condensation releases heat. A thunderstorm happens when condensation releases so much heat that the air starts to rise even faster, pulling more air up behind it. The moisture in this air then condenses, releasing more heat and pulling more air up, and so on. This is why thunderstorms often rise to a much greater height than the surrounding clouds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Condensation releases heat, but evaporation uses up heat, which is why you feel cooler when you sweat. When water evaporates it takes heat away from the surface. That heat was put there by sunlight, and it gets released back again at the top of the thunderstorm. So a thunderstorm is part of a large-scale heat transport process that begins with evaporative cooling at the Earth's surface, and ends with the heat from condensation being transported into the upper atmosphere and ultimately radiated away into space.&lt;/p&gt;&#xA;" OwnerUserId="215" LastActivityDate="2014-05-26T08:01:30.147" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="1018" PostTypeId="2" ParentId="1015" CreationDate="2014-05-26T15:47:05.753" Score="7" Body="&lt;p&gt;All unit cells are parallel-sided hexahedra. These are six sided shapes with parallel opposite sides. Their three principle angles may or may not be 90 degrees. And the three side lengths may or may not be equal. All of these unit cells can be uniformly stacked.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using these building blocks it is only possible to produce planes of reflection, diads (axis of rotational symmetry order 2), triads, tetrads, and hexads.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, a cube (all sides the same length, all angles 90 degrees) has diads, triads, and tetrads; plus planes of reflection.&#xA;A hexagonal symmetry can be used with 60 / 120 degree angles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that it is impossible to produce a regular arrangement of unit cells to produce a pentad (order 5 symmetry). As @Nathaniel says, this can be almost achieved using Penrose Tiles (2d mathematical constructions), and quasicrystals (real 3d materials). Quasicrystals will produce an x-ray diffraction pattern with a pentad, but the actual atoms do not follow a true 5-fold symmetry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suspect your confusion is over the final (macroscopic) crystal shape and the unit cell shape. These are rarely the same. (Salt being an example where they are; but diamonds, garnets, do not)&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2014-05-26T15:47:05.753" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="1019" PostTypeId="1" CreationDate="2014-05-26T17:30:42.377" Score="13" ViewCount="184" Body="&lt;p&gt;As in, does the debris in the patch area eventually sink?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And if so, could sedimentation measurements over these regions provide a more fine-scaled measure of environmental conditions than sedimentation measurements over other regions?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorDisplayName="user889" LastEditDate="2015-02-28T11:25:33.967" LastActivityDate="2015-02-28T11:25:33.967" Title="Does the Great Pacific Garbage Patch increase sedimentation rates over the patch?" Tags="|ocean|sedimentology|pollution|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="1021" PostTypeId="2" ParentId="1005" CreationDate="2014-05-26T21:29:14.983" Score="3" Body="&lt;ul&gt;&#xA;&lt;li&gt;Date/timestamps are tricky to convert without further information; are the values you show days (unlikely, if 990555 is your date/time value), hours, seconds? See if you can figure out the system used (either by knowing which date your timestamp is supposed to represent, or looking at the step sizes for the data); this will generally give you an idea of what is being represented, and how to convert to an actual date.&lt;/li&gt;&#xA;&lt;li&gt;Coordinate and long/lat are basically the same thing, only built up from decimals or hours/minutes (e.g. 0.5 representing 30 minutes). Conversion can be found &lt;a href=&quot;http://transition.fcc.gov/mb/audio/bickel/DDDMMSS-decimal.html&quot; rel=&quot;nofollow&quot;&gt;http://transition.fcc.gov/mb/audio/bickel/DDDMMSS-decimal.html&lt;/a&gt;, for instance. Mind that other coordinate systems are also possible, which will make the conversion different; again, this is important to figure out before you can convert your data.&lt;/li&gt;&#xA;&lt;li&gt;Comparison options will depend on: 1) whether your data corresponds (do you have measurements on the same date/time, as well as the same location?), 2) what you are interested in.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="446" LastActivityDate="2014-05-26T21:29:14.983" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="1022" PostTypeId="1" AcceptedAnswerId="1041" CreationDate="2014-05-27T00:37:55.493" Score="14" ViewCount="183" Body="&lt;p&gt;A number of popular writings on &lt;a href=&quot;http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor&quot;&gt;the natural fission reactor at Oklo, Gabon&lt;/a&gt; (e.g. &lt;a href=&quot;http://gizmodo.com/there-s-a-naturally-occurring-nuclear-fission-reactor-i-1475445638&quot;&gt;here&lt;/a&gt;) state that some of the energetic byproducts (krypton and xenon, presumably &lt;sup&gt;85&lt;/sup&gt;Kr and &lt;sup&gt;133&lt;/sup&gt;Xe) of the reactor were &quot;trapped&quot; in aluminophosphate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How, exactly, does &quot;aluminophosphate&quot; (I assume this is some sort of framework mineral?) trap gaseous elements? Is it related to the mechanism by which clathrates trap gases? &lt;/p&gt;&#xA;" OwnerUserId="67" LastActivityDate="2014-05-29T01:12:15.817" Title="In what sense did the Oklo reactor &quot;trap&quot; its own nuclear waste?" Tags="|geology|earth-history|mineralogy|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="1023" PostTypeId="1" AcceptedAnswerId="1028" CreationDate="2014-05-27T01:32:04.250" Score="16" ViewCount="8622" Body="&lt;p&gt;The gravitational influence of the gas giants (plus general-relativistic effects) are known to cause the apses of the Earth's orbit to precess. For an illustration of that process, see &lt;a href=&quot;http://en.wikipedia.org/wiki/File%3aPrecessing_Kepler_orbit_280frames_e0.6_smaller.gif&quot;&gt;this image&lt;/a&gt;. Now, it's clear that apsidal precession &lt;em&gt;combined&lt;/em&gt; with changes in orbital eccentricity will affect climate - at minimum, this changes the mean (year-averaged) Earth-Sun distance, which one would of course expect to have an effect on climate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not really following how apsidal precession &lt;em&gt;alone&lt;/em&gt; is supposed to affect climate, though. Let us suppose that the Earth's &quot;rotational parameters&quot; (e.g. axial tilt) are held constant, and that the orbit of the Earth is static &lt;em&gt;except&lt;/em&gt; for apsidal precession (i.e. no changes in eccentricity, no orbital decay, etc.). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this case, the total insolation experienced by the Earth over the course of a year should be independent of how much the apses have precessed - indeed, an observer looking at the Sun-Earth system from above the ecliptic plane should not be able to distinguish between, say, a 5-degree precession of the apses and a 5-degree rotation of the observer in the opposite direction. Since the latter cannot affect the Earth's climate, we should neither expect the former to.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clearly, I'm making some sort of mistake here, but I'm not sure where exactly my thinking has gone wrong. Where is my error?&lt;/p&gt;&#xA;" OwnerUserId="67" LastActivityDate="2014-07-02T16:06:21.667" Title="How does the precession of the Earth's apses affect climate?" Tags="|climate|milankovitch-cycles|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1024" PostTypeId="5" CreationDate="2014-05-27T02:35:03.313" Score="0" Body="" OwnerUserId="20" LastEditorUserId="20" LastEditDate="2014-05-27T02:35:03.313" LastActivityDate="2014-05-27T02:35:03.313" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1025" PostTypeId="4" CreationDate="2014-05-27T02:35:03.313" Score="0" Body="Paleobotany is the branch of paleobiology dealing with the recovery and identification of plant remains from geological contexts, and their use for the biological reconstruction of past environments (paleobiogeography), and both the evolutionary history of plants, with a bearing upon the evolution of life in general." OwnerUserId="20" LastEditorUserId="20" LastEditDate="2014-05-27T02:35:03.313" LastActivityDate="2014-05-27T02:35:03.313" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1026" PostTypeId="1" AcceptedAnswerId="1036" CreationDate="2014-05-27T02:49:44.910" Score="7" ViewCount="470" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Creation_Museum&quot; rel=&quot;noreferrer&quot;&gt;The Creation Museum&lt;/a&gt; is a terrifying place for scientists of all stripes. One of their exhibits is the &quot;Flood Geology&quot; exhibit, which purports to explain how a flood of (literally) Biblical proportions circa 6000 years ago explains all the features of the Earth we see today. One panel at that exhibit is titled &quot;Evidences of the Flood in the Grand Canyon&quot;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.flickr.com/photos/scalzi/1969202697/sizes/o/&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xcEdml.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;(photo taken by John Scalzi; click for larger, more-readable version - if you think you can handle it)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is obviously boneheaded in so, so many ways, but anyway - this panel makes the following claim:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Sand grains in the Coconino Sandstone come from the Appalachian Mountains.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Three related questions:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Is this claim true? (The Creation Museum is not beyond telling outright lies, so I have to ask...)&lt;/li&gt;&#xA;&lt;li&gt;If so, how did it get there?&lt;/li&gt;&#xA;&lt;li&gt;How do we determine that a particular grain of sand originates in the Appalachians? &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="67" LastEditorDisplayName="user20559" LastEditDate="2021-06-27T11:34:46.117" LastActivityDate="2021-06-27T11:34:46.117" Title="Is it true that &quot;[sand] grains in the Coconino Sandstone come from the Appalachian Mountains&quot;?" Tags="|geology|sedimentology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="1027" PostTypeId="1" AcceptedAnswerId="2941" CreationDate="2014-05-27T10:32:43.867" Score="12" ViewCount="697" Body="&lt;p&gt;There's an awful lot of argon in the atmosphere: about 0.93% of the atmosphere is argon&lt;sup&gt;&lt;a href=&quot;http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html&quot; rel=&quot;nofollow&quot;&gt;[1]&lt;/a&gt;&lt;/sup&gt;, making it the third-most abundant gas after N&lt;sub&gt;2&lt;/sub&gt; and O&lt;sub&gt;2&lt;/sub&gt;. As I understand it, most of it is produced by the following decay path: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\ce{^{40}_{19}K + ^{0}_{-1}e- -&amp;gt; ^{40}_{18}Ar + \gamma{} + \nu_{e}}&#xA;%edit&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How does all this radiogenic argon make it into the atmosphere, though? Most of the decaying potassium-40 must surely be at some depth beneath the surface, thus trapping the argon-40 in the interior of the Earth, right?&lt;/p&gt;&#xA;" OwnerUserId="67" LastEditorUserId="2665" LastEditDate="2016-07-21T04:58:32.590" LastActivityDate="2016-07-21T04:58:32.590" Title="How does radiogenic argon-40 get into the atmosphere?" Tags="|atmosphere|radioactivity|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1028" PostTypeId="2" ParentId="1023" CreationDate="2014-05-27T11:10:08.720" Score="11" Body="&lt;p&gt;During the 20&lt;sup&gt;th&lt;/sup&gt; century, the global mean temperature in January was 12°C while it was 15.8°C in July. This is a bit paradoxical as insolation is currently about 7% higher during January than it is in July. So why is July warmer than January?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The solution to this apparent paradox and the answer your question (how does apsidal precession alone affect the climate) are one and the same: The uneven distribution of land and water between the northern and southern hemispheres. The northern hemisphere has about twice as much land as does the southern hemisphere. Continental climates exhibit much more seasonal variability than do maritime climates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That worldwide insolation is greatest in January and least in July is a bit irrelevant. What is more relevant is the length of the seasons in the northern hemisphere. Right now, summer is longer than is winter in the northern hemisphere because perihelion is in early January. This situation will be reversed in ten thousand years when perihelion and northern hemisphere summer solstice coincide. Looking at precession only, glaciation is much more likely during periods where northern hemisphere summers are short and winters are long.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-05-27T11:10:08.720" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="1029" PostTypeId="1" AcceptedAnswerId="1038" CreationDate="2014-05-27T13:50:26.110" Score="19" ViewCount="6431" Body="&lt;p&gt;I'm developing an Android app which uses a pressure sensor. Due to storage limitations I have to normalize and scale the atmospheric pressure values. For this I need to know the &lt;strong&gt;extreme values of pressure&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Different conditions should be respected, e.g.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Weather conditions (low/high)&lt;/li&gt;&#xA;&lt;li&gt;Locations (high mountains, deep valleys like &lt;a href=&quot;http://en.wikipedia.org/wiki/Dead_Sea&quot;&gt;Dead Sea&lt;/a&gt; with a surface elevation of: -427 m (−1,401 ft))&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;If this is unknown, does anybody know the range at sea level? Something like 1013 hPa ± X?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With a formula I've found I calculated that the pressure on Mount Everest should be something like 300 hPa and at Dead Sea about 53 hPa more than at sea level. But this is not a very complex formula, so these values might be theoretical and wrong.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit / additional info&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I discovered that my sensor provides values like 980.01 hPa, so there are 2 digits precision (don't know whether this reflects sensor precision). A difference of 0.01 hPa means ~8cm altitude. This might sound little, but I need to calculate the current incline of athletes, so I cannot sacrifice precision. My current scaling algorithm produces normalized numbers from 0 to 32768. It would imply much work to change the output range.&lt;/p&gt;&#xA;" OwnerUserId="530" LastEditorUserId="81" LastEditDate="2014-05-31T09:02:17.147" LastActivityDate="2017-10-07T10:33:27.157" Title="What is the range of possible atmospheric pressures on the surface of the Earth?" Tags="|meteorology|barometric-pressure|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="1030" PostTypeId="2" ParentId="1027" CreationDate="2014-05-27T14:54:33.510" Score="10" Body="&lt;p&gt;Most of this &lt;sup&gt;40&lt;/sup&gt;Ar makes its way to the atmosphere in two primary ways. Firstly, since most of the K is concentrated in the continental crust, volcanic eruptions on the continents over geological time have concentrated Ar in the atmosphere. Since it is too heavy and inert to decrease in any appreciable method it has a long residence time. Secondly, volcanism at mid-oceanic ridges releases Ar into the ocean and then into the atmosphere. The current combined rate of these volcanic events is ~ 2.2×10&lt;sup&gt;9&lt;/sup&gt; grams/year.&lt;/p&gt;&#xA;" OwnerUserId="500" LastEditorUserId="725" LastEditDate="2014-12-03T04:48:11.183" LastActivityDate="2014-12-03T04:48:11.183" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1033" PostTypeId="1" AcceptedAnswerId="1040" CreationDate="2014-05-28T02:16:07.343" Score="11" ViewCount="393" Body="&lt;p&gt;In every professional field, practitioners may come home at the end of the day and say &quot;Yeah! I knocked it out of the park!&quot;, or alternatively &quot;Oh, man. Gotta do better tomorrow.&quot; What about meteorologists?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When a meteorologist makes a weather forecast, she will strive to &quot;get it right&quot;, so that when the date in question arrives her prediction will have matched the actual temperature, dew point, wind velocity and direction, precipitation, etc. But, when that date arrives, and the actual conditions have been measured and compared to the prediction, how is the prediction graded?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Precipitation seems to be the most problematic aspect, as it's quite nonlinear and predicted statistically. What does it mean to have &quot;gotten it right&quot; by predicting a 30% chance of precipitation? Yes, it rained 30% of the time? Yes, it rained in 30% of the forecast area? Yes, 30% of the public will answer &quot;Yes&quot; if asked whether it rained?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's complexity in the other metrics as well. For instance, how are errors in the different values compared? Would it be better to get the temperature spot on but the wind velocity 5MPH high, or the wind exactly right but the temperature 5&amp;deg;F high? What about timing: what if that front came through two hours after it was predicted?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: part of the difficulty is getting clarity about the consumer of the weather information. Fred the Farmer wants to know how much rain he can expect in next day or so, but the exact timing probably isn't important. Pete the Party Planner wants to herd his guests into the bar before the front comes through, but if it's going to rain he probably doesn't care whether it drops a quarter inch or a half. And Francine the Fisherman doesn't really care about the precipitation at all (within limits); her world centers around wind and waves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I may want to post a second question that is explicitly from the consumer viewpoint: given weather data and meteorologists' historical forecasts, how would I choose a meteorologist?&lt;/p&gt;&#xA;" OwnerUserId="534" LastEditorUserId="534" LastEditDate="2014-05-31T10:50:34.713" LastActivityDate="2014-05-31T10:50:34.713" Title="How do meteorologists grade their past forecasts?" Tags="|weather|weather-forecasting|" AnswerCount="2" CommentCount="5" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1034" PostTypeId="1" CreationDate="2014-05-28T07:31:22.727" Score="10" ViewCount="5990" Body="&lt;p&gt;Why does quartz have no cleavage plane and halite does? What do I need to know about the specific mineral so that I can decide whether it has cleavage or not? I need some kind of rule.&lt;/p&gt;&#xA;" OwnerUserId="521" LastActivityDate="2014-06-05T23:10:18.690" Title="What kind of minerals have no cleavage plane?" Tags="|crystals|mineralogy|crystallography|minerals|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1035" PostTypeId="1" CreationDate="2014-05-28T10:56:36.720" Score="13" ViewCount="373" Body="&lt;p&gt;I, and many of my palaeomagnetist colleagues, often use thermal demagnetization (potentially up to 800°C) in our studies. Usually a stepwise technique is employed, so each sample is heated -- often 20 or more times -- to progressively higher temperatures. This can become a problem with jointed or friable samples: the pieces have to be glued together in order to make a measurement, but there are very few adhesives which are both heatproof and non-magnetic. By ‘non-magnetic’ I mean that it should carry as little remanence as possible; while it would also be nice if it had a negligible magnetic susceptibility, this is a less important factor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In my search for an adhesive which is heatproof as well as non-magnetic, I've looked at:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;UHU. Good bond, non-magnetic, but not very heatproof. Even the high-temperature version breaks down at about 250°C. Beyond that, every heating step leaks noxious burning-glue fumes into the lab and I have to re-glue all the samples before measuring them.&lt;/li&gt;&#xA;&lt;li&gt;Cyanoacrylate (a.k.a. superglue). Non-magnetic, and bond usually OK, at least on fine-grained rocks. Even less heat-tolerant than UHU, but the fumes are a bit less noxious at least.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.aremco.com/wp-content/uploads/2010/11/A02_13.pdf&quot;&gt;Aremco Ceramabond 571&lt;/a&gt;, a magnesium oxide based paste which easily fulfils the temperature requirement (it's rated to 1760°C) and was recommended to me as non-magnetic (albeit not by the manufacturer). Unfortunately it turned out to carry a significant mangetic remanence, and contaminated measurements unacceptably. (It might work reasonably for strongly-magnetized volcanic samples, though.)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Sodium_silicate&quot;&gt;Sodium silicate&lt;/a&gt; in aqueous solution, a.k.a. water glass. Magnetically, this fits the bill. Kostadinova et al. (2004) reported that it doesn't appear to affect remanence measurements (although it does alter susceptibility). It's thermally stable up to the temperatures I care about and beyond. With clay-rich material I had some trouble with expansion (intumescence) of treated samples upon heating and have heard from other researchers that this is a known problem; Otaka et al. (2002) indicate that heating rate is also a factor. Another problem is that the adhesive properties are not ideal: sodium silicate works well as a binder for soaking and impregnating loose, friable material, but doesn't make a good contact adhesive for less porous rock. &lt;/li&gt;&#xA;&lt;li&gt;Automotive silicone adhesives: I have seen various silicone adhesives designed for work on automotive exhaust systems. They would probably fulfil the temperature and adhesive requirements, but I haven't yet done any pilot studies on their magnetic properties. Given the intended applications, there's no reason for the manufacturers to specifically exclude magnetic compounds from the mix. I'd be interested to hear if anyone's tried any adhesives of this sort.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I should add that the adhesive requirements are actually very modest: the join doesn't have to bear any load beyond the weight of the sample itself, which will not exceed 50g.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Kostadinova, M., Jordanova, N., Jordanova, D., &amp;amp; Kovacheva, M. (2004). Preliminary study on the effect of water glass impregnation on the rock-magnetic properties of baked clay. &lt;em&gt;Studia Geophysica et Geodaetica&lt;/em&gt;, 48(3), 637-646.&lt;/li&gt;&#xA;&lt;li&gt;Otaka, T., &amp;amp; Asako, Y. (2002). Thermal intumescent characteristics of heated sodium silicate. &lt;em&gt;In ASME 2002 International Mechanical Engineering Congress and Exposition&lt;/em&gt; (pp. 205-210). American Society of Mechanical Engineers.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="94" LastActivityDate="2014-07-13T13:10:34.817" Title="What can I use as a heatproof, non-magnetic glue for samples?" Tags="|laboratory|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="1036" PostTypeId="2" ParentId="1026" CreationDate="2014-05-28T13:18:52.287" Score="14" Body="&lt;p&gt;Jeffrey Ralh of Yale and coauthors published &lt;a href=&quot;http://geology.gsapubs.org/content/31/9/761.short&quot;&gt;Combined single-grain (U-Th)/He and U/Pb dating of detrital zircons from the Navajo Sandstone, Utah&lt;/a&gt;, which concludes that Navajo sandstone originated from the Appalachian Mountains.  A review of the article is found here: &lt;a href=&quot;http://www.geotimes.org/nov03/NN_navajo.html&quot;&gt;http://www.geotimes.org/nov03/NN_navajo.html&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rahl et al. propsed that a large river system transported the sediment.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, Ralh's research concerned only Navajo sandstone, not Coconino sandstone as far as I know.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.ees.lehigh.edu/ftp/retreat/outgoing/for_team_appalachians/appalachians_paper/dickinson_gerhrels_2003_sedimentary_geology_zircons.pdf&quot;&gt;U–Pb ages of detrital zircons from Permian and Jurassic eolian sandstones of the Colorado Plateau, USA: paleogeographic implications&lt;/a&gt; does investigate Coconino Sandstone and other sandstones from the region and discusses what fraction are of Appalachian origin and transport mechanisms. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;34% of Coconino Sandstone zircon grains are reported to be of Appalachian origin in table 4.&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2014-05-29T14:56:35.777" LastActivityDate="2014-05-29T14:56:35.777" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="1037" PostTypeId="1" AcceptedAnswerId="1039" CreationDate="2014-05-28T15:48:22.937" Score="13" ViewCount="828" Body="&lt;p&gt;If I release some ozone gas (O&lt;sub&gt;3&lt;/sub&gt;) to the atmosphere, for how much time will it stay there in its original form? Does it change to some other form by reacting with other atmospheric constituents?&lt;/p&gt;&#xA;" OwnerUserId="536" LastEditorUserId="219" LastEditDate="2014-12-11T22:39:36.920" LastActivityDate="2014-12-11T22:39:36.920" Title="Ozone gas (O₃) endurance in the atmosphere" Tags="|atmosphere|ozone|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="1038" PostTypeId="2" ParentId="1029" CreationDate="2014-05-28T15:58:35.940" Score="19" Body="&lt;p&gt;Presssure at the Mt. Everest summit has been measured to be 253 Torr (337 hPa).  &lt;a href=&quot;http://jap.physiology.org/content/86/3/1062&quot;&gt;http://jap.physiology.org/content/86/3/1062&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pressure at the Dead Sea as high as 1079 hPa is reported in Fig. 12 of this reference: &lt;a href=&quot;http://isramar.ocean.org.il/isramar2009/DeadSea/Hecht&amp;amp;Gertman_2003_DS_Climate_Chapter4.pdf&quot;&gt;http://isramar.ocean.org.il/isramar2009/DeadSea/Hecht&amp;amp;Gertman_2003_DS_Climate_Chapter4.pdf&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as at sea level, 870 hPa was measured for typhoon Tip in 1979. &lt;a href=&quot;http://www.wunderground.com/blog/weatherhistorian/world-and-us-lowest-barometric-pressure-records&quot;&gt;http://www.wunderground.com/blog/weatherhistorian/world-and-us-lowest-barometric-pressure-records&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And 1067 hPa at coastal areas of Estonia and Lativa are reported here: &lt;a href=&quot;http://www.wunderground.com/blog/weatherhistorian/world-and-us-anticyclonic-high-barometric-pressure-records&quot;&gt;http://www.wunderground.com/blog/weatherhistorian/world-and-us-anticyclonic-high-barometric-pressure-records&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2014-05-28T16:15:46.483" LastActivityDate="2014-05-28T16:15:46.483" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1039" PostTypeId="2" ParentId="1037" CreationDate="2014-05-28T16:50:06.850" Score="13" Body="&lt;p&gt;$\mathrm{O}_3$ decomposes to $\mathrm{O}_2$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rate of decomposition increases with temperature. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At 20 degrees C, the half-life is about 3 days in air.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\mathrm{NO}$ can catalyze the formation and decomposition of ozone.  &lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="725" LastEditDate="2014-12-03T04:52:04.737" LastActivityDate="2014-12-03T04:52:04.737" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="1040" PostTypeId="2" ParentId="1033" CreationDate="2014-05-28T19:20:10.073" Score="8" Body="&lt;p&gt;Disclaimer: I am not a meteorologist.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer this question, you need to understand how a forecast is obtained. Basically, meteorologists run computer simulations that predict how weather systems might evolve from current measurements. In fact, data assimilation techniques (&lt;a href=&quot;http://en.wikipedia.org/wiki/Data_assimilation&quot;&gt;http://en.wikipedia.org/wiki/Data_assimilation&lt;/a&gt;) are commonly used, so that the predictions given by the model depend not only on current observations, but also upon the history of the weather system. As new data comes in, the evolving model is adjusted towards those values - but not forced to match exactly, as that would destroy the historical information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any one model is therefore not expected to be entirely accurate. However, if we run many models simultaneously, and include random variations to reflect the chaotic nature of the weather system (and measurement errors), we obtain something called an &quot;ensemble forecast&quot;. This is where the 30% chance of rain comes from: 30% of the simulations predict rain in your area, while the others think it will remain dry. Average/minimum/maximum temperatures etc can also easily be extracted from the ensemble.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, the accuracy of a forecast can be considered in different ways. It is certainly possible to compare the predictions of one ensemble member to observations: this is an integral part of the data assimilation process. However, it is not necessarily a problem if a member performs poorly on one particular occasion. Different types of measurements may be weighted differently during the comparison (so matching rainfall might be deemed 'more important' than matching temperature; this may vary depending on the type of forecast/its intended use). More generally, you have to look at the long-term statistics of the errors in the forecast. So, if you look at several months of data, did it rain on around a third of the days when you predicted a 30% chance of rain? On average, are your temperature predictions reasonably accurate? Making this assessment on a day-by-day basis is unlikely to be in keeping with the statistical basis of modern weather forecasting.&lt;/p&gt;&#xA;" OwnerUserId="427" LastEditorUserId="427" LastEditDate="2014-05-28T19:44:41.087" LastActivityDate="2014-05-28T19:44:41.087" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="1041" PostTypeId="2" ParentId="1022" CreationDate="2014-05-29T01:12:15.817" Score="8" Body="&lt;p&gt;According to &lt;a href=&quot;http://presolar.wustl.edu/laboratory_for_space_sciences/Publications_2004_files/Meshik-PRL-04.pdf&quot;&gt;Record of Cycling Operation of the Natural Nuclear Reactor in the Oklo/Okelobondo Area in Gabon&lt;/a&gt;, the Xe is trapped in crystalline cage-like structures formed of the aluminum phosphate that are similar to &lt;a href=&quot;http://en.wikipedia.org/wiki/Zeolite&quot;&gt;zeolites&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reference also explains that the aluminum phosphate structures grow quickly under hydrothermal conditions of 270-300 degrees C.&lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2014-05-29T01:12:15.817" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1042" PostTypeId="1" AcceptedAnswerId="1043" CreationDate="2014-05-29T04:52:34.833" Score="11" ViewCount="6330" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Massif&quot;&gt;Wikipedia&lt;/a&gt; says that a massif is &quot;a section of a planet's crust that is demarcated by faults or flexures.&quot; It goes on to list mountain-like objects.&#xA;Is it not true that most mountains are created by faults or flexures? What is it that distinguishes a massif from any other mountain or group of mountains?&lt;/p&gt;&#xA;" OwnerUserId="540" LastActivityDate="2015-12-13T22:08:45.063" Title="What is a massif and what differentiates it from other types of mountains?" Tags="|geophysics|mountains|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="1043" PostTypeId="2" ParentId="1042" CreationDate="2014-05-29T09:46:58.210" Score="8" Body="&lt;p&gt;My interpretation is that while an individual &lt;em&gt;mountain&lt;/em&gt; itself may be part of a &lt;em&gt;mountain range&lt;/em&gt; that is marked out by faults and flexures, the actual &lt;em&gt;mountain&lt;/em&gt; is demarcated by erosive processes. For example, the Alps in France are a &lt;em&gt;mountain range&lt;/em&gt;, demarcated by faults. However, the Matterhorn, shown below, is clearly a mountain figure not marked out by faults or crustal flexing. Instead its prominence from the surrounding regions is caused by the erosion processes of glaciers.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oN7zf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oN7zf.jpg&quot; alt=&quot;from http://www.about.ch/cantons/valais/matterhorn.jpg&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To use the example in &lt;a href=&quot;https://en.wikipedia.org/wiki/Massif&quot; rel=&quot;nofollow noreferrer&quot;&gt;the &lt;em&gt;massif&lt;/em&gt; Wikipedia article&lt;/a&gt;, The Mont Blanc Massif contains peaks within it (Aguille du Midi, the Mont Blanc peak etc., shown below) that are defined by erosion, but the group of these peaks is defined by faulting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kbYrM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kbYrM.jpg&quot; alt=&quot;image from https://upload.wikimedia.org/wikipedia/commons/thumb/1/15/Massif_du_Mont-Blanc_%28hiver_panoramique%29.jpg/800px-Massif_du_Mont-Blanc_%28hiver_panoramique%29.jpg&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="389" LastEditorUserId="28050" LastEditDate="2015-12-13T22:08:45.063" LastActivityDate="2015-12-13T22:08:45.063" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1044" PostTypeId="1" CreationDate="2014-05-29T10:53:42.533" Score="13" ViewCount="314" Body="&lt;p&gt;A supervisor of mine made an off-hand comment about the fact that Mars used to have plate tectonics, and there is evidence that Mars used to have plate tectonics, however now it does not. The theory that she mentioned was that Mars is &lt;strong&gt;either&lt;/strong&gt; heterogenoeous &lt;strong&gt;or&lt;/strong&gt; homogeneous, however I have forgotten which one she said! Now I can't find anything online which says which one it is! Can anyone help me out here?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, the follow on from this was that this led to the ceasing of mantle convection which ended the possibilities of plate tectonics? Could somebody more knowledgable than I perhaps outline a theory of why this is? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition if mantle convection has ceased, than when do we think it stopped being active? &lt;/p&gt;&#xA;" OwnerUserId="389" LastEditorUserId="64" LastEditDate="2015-01-07T02:49:15.850" LastActivityDate="2015-01-07T02:49:15.850" Title="Is Mars' mantle homogeneous or heterogeneous and what might this say about mantle convection?" Tags="|planetary-science|mantle|convection|mars|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1045" PostTypeId="1" AcceptedAnswerId="1049" CreationDate="2014-05-29T11:58:26.540" Score="10" ViewCount="766" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Ganges#Avatarana_or_Descent_of_the_Ganges&quot;&gt;Avatarana or Descent of the Ganges&lt;/a&gt; (extracted from Wikipedia):&lt;br&gt;&#xA;  &quot;In late May or early June every year, Hindus celebrate the avatarana&#xA;  or descent of the Ganges from heaven to earth.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There are several Hindu versions for the birth of the river Ganges.&lt;br&gt;&#xA;I'm here interested in the scientific version:  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Question&lt;/strong&gt;: When (and how) this river was born (geological period)?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="537" LastActivityDate="2014-05-30T12:39:42.203" Title="What's the geological period of the birth of the river Ganges?" Tags="|geology|hydrology|rivers|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1046" PostTypeId="1" CreationDate="2014-05-29T15:33:31.477" Score="11" ViewCount="145" Body="&lt;p&gt;How would one go about estimating litter production (fine root turnover, leaves, etc.) for a forested area? I have some estimates from literature - which were derived from models, but I'd like to create my own estimate to compare. &lt;/p&gt;&#xA;" OwnerUserId="383" LastEditorUserId="4789" LastEditDate="2016-01-08T21:49:59.003" LastActivityDate="2016-10-31T16:41:28.500" Title="Estimate litter production" Tags="|soil|carbon-cycle|forest|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="1048" PostTypeId="1" AcceptedAnswerId="4304" CreationDate="2014-05-29T18:35:54.900" Score="22" ViewCount="130795" Body="&lt;p&gt;I couldn't find the definitions from either source:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://geology.com/geology-dictionary.shtml&quot; rel=&quot;noreferrer&quot;&gt;Geology Dictionary&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.ge-at.iastate.edu/glossary-of-geologic-terms/&quot; rel=&quot;noreferrer&quot;&gt;Glossary of Geologic Terms&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="538" LastEditorDisplayName="user20559" LastEditDate="2021-05-11T21:01:33.540" LastActivityDate="2021-05-11T21:01:33.540" Title="Is there a difference between rock and stone?" Tags="|geology|rocks|petrology|terminology|" AnswerCount="6" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="1049" PostTypeId="2" ParentId="1045" CreationDate="2014-05-30T12:39:42.203" Score="6" Body="&lt;p&gt;From &lt;a href=&quot;http://www.iitk.ac.in/infocell/iitk/newhtml/storyoftheweek51.htm&quot;&gt;How Old is Our Ganga&lt;/a&gt;, the Ganges &quot;formed as a consequence of the India-Asia collision around 55 million years ago resulting in the formation of the Himalaya. This provided a large continental mass which together with large rainfall in the catchment area and long term erosion generated /enlarged the river valleys&quot;.&lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2014-05-30T12:39:42.203" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1051" PostTypeId="2" ParentId="1048" CreationDate="2014-05-30T14:02:00.967" Score="2" Body="&lt;p&gt;The definition I've seen before is one of &lt;em&gt;context&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You know where a rock came from - eg. you may have recorded it in your field notebook.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A stone has an unknown origin - eg. stones  on the road, in a river, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As such, I guess most glacial erratics are technically stones rather than rocks :-)&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2014-05-30T14:02:00.967" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1052" PostTypeId="2" ParentId="1048" CreationDate="2014-05-30T15:57:34.950" Score="10" Body="&lt;p&gt;Most sources say that rocks are made of stones. (Or at least that stones are rock fragments.)  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the Bing dictionary (definition of stone):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ol&gt;&#xA;  &lt;li&gt;hard nonmetallic material: the hard solid nonmetallic substance &lt;strong&gt;that rocks are made of&lt;/strong&gt;.  &lt;/li&gt;&#xA;  &lt;li&gt;rock fragment: &lt;strong&gt;a small piece of rock&lt;/strong&gt; of any shape  &lt;/li&gt;&#xA;  &lt;li&gt;shaped &lt;strong&gt;rock fragment&lt;/strong&gt;: a &lt;strong&gt;piece of rock&lt;/strong&gt; that has been shaped for a particular purpose, e.g. a gravestone&lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Quoting from a blog post by David B. Williams on &lt;a href=&quot;http://geologywriter.com/blog/stories-in-stone-blog/rock-or-stone-is-there-a-difference/&quot;&gt;geologywriter.com&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... The first definition for rock is “A large rugged mass of hard mineral material or stone.” ... defines stone as “A piece of rock or hard mineral substance of a small or moderate size,”... &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;Some other things people think distinguish the two:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...some people thought that stone was more British; that rock could be hard and soft, whereas stone was always hard; that stones are smooth and rocks rough; and that stones are small and rocks are big. In his wonderful book, Stone by Stone, Robert Thorson writes “Rock is raw material in situ. Stone usually connotes either human handling or human use, although it can also be used to describe naturally produced fragments of rock larger than a cobble.”  &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(Quoted from that same post mentioned above)&lt;/p&gt;&#xA;" OwnerUserId="115" LastActivityDate="2014-05-30T15:57:34.950" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1053" PostTypeId="1" CreationDate="2014-05-30T17:08:19.370" Score="11" ViewCount="467" Body="&lt;p&gt;If you were to do a slug-in test where you put in a known volume of water, would there be a point where, say if the formation was extremely permeable, the permeability of the screen itself would be measured?&lt;/p&gt;&#xA;" OwnerUserId="541" LastActivityDate="2019-12-06T05:06:32.207" Title="Permeability of well screen as a limitation to a slug-in test" Tags="|hydrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1054" PostTypeId="1" AcceptedAnswerId="1058" CreationDate="2014-05-30T20:01:37.020" Score="8" ViewCount="1308" Body="&lt;p&gt;I've seen in several places that there seems to be an extinction cycle on Earth of approximately 27 million years. I've read this here:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.dailymail.co.uk/sciencetech/article-1294372/Life-Earth-wiped-27-million-years.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Life on Earth wiped out every 27 million years (but we've got about 16 million years until the next one)&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;And also saw a similar explanation on Cosmos last week. Since the Earth is about 4.54 billion years old, that means there have been around 168 different extinction cycles. From what I understand, the Earth will either heat or freeze at extreme temperatures and then either cool or warm until water and life is a possibility again.&lt;/p&gt;&#xA;&lt;p&gt;Given that this is correct (and definitely correct if I'm wrong, I'm eager to learn!), what are the chances there was a full civilization like ours that got completely wiped out in a different extinction cycle than ours? Is it possible or are there other factors in the history of our planet that would have prevented life from flourishing to the point that we are in now? I do understand that the factors of creating humans exactly like us are pretty drastically low but I suppose I'm referring to 'civilization' as intelligent life.&lt;/p&gt;&#xA;&lt;p&gt;And a second part to the question, I know there are fossil records in the different layers of sedimentary rock but would there ever have possibly been an extinction event that ruined the Earth so drastically that it destroyed fossils and rocks (i.e. records of the past)? I've read that the oldest fossil found was 3.5 billion years old but it's not conclusive. Do we have a vast record of fossils and life that is billions of years old?&lt;/p&gt;&#xA;" OwnerUserId="542" LastEditorUserId="18088" LastEditDate="2023-02-14T05:45:29.530" LastActivityDate="2023-02-14T05:45:29.530" Title="Life on Earth previous to us" Tags="|earth-history|paleontology|fossils|mass-extinction|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="1055" PostTypeId="2" ParentId="1037" CreationDate="2014-05-30T22:48:16.537" Score="10" Body="&lt;p&gt;Really, it is impossible to know how long ozone will persist in the troposphere without knowing what the other chemical concentrations (e.g. CO, NO&lt;sub&gt;x&lt;/sub&gt;, HO&lt;sub&gt;x&lt;/sub&gt;) are and what your photolysis rates are (is it night? cloudy? what latitude? how many hours of sunshine?). Ozone is constantly cycling in the presence of sunlight, so if you are concerned about total overall ozone (not just the molecules you released), you will get a very different answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As indicated by DavePhD, the amount of NO&lt;sub&gt;x&lt;/sub&gt; in the region will greatly influence the rate that ozone is converted.  In an atmosphere with relatively low levels of NO&lt;sub&gt;x&lt;/sub&gt;, it will persist for a few days.  If there is no photolysis (e.g. night time) then ozone won't get re-created and high levels of NO&lt;sub&gt;x&lt;/sub&gt; would titrate out most of your ozone overnight.  Though there is a happy medium where moderate levels of NOx will actually increase your total ozone concentrations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also it is important to keep in mind that if there is enough CO in the air, OH reactions with ozone will decrease, as the OH will preferably react with CO, and ozone loss will occur more slowly.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another important thing to consider is that without rain, HNO&lt;sub&gt;3&lt;/sub&gt; (which is created when NO&lt;sub&gt;2&lt;/sub&gt; reacts with OH) will not deposit and ozone precursors can persist for many days, allowing more ozone to be re-created.  Finally, don't forget that ozone does get dry deposited as well, so the land surface does have some influence on loss rates.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="67" LastEditDate="2014-05-31T01:27:52.837" LastActivityDate="2014-05-31T01:27:52.837" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1056" PostTypeId="2" ParentId="1033" CreationDate="2014-05-30T23:16:20.833" Score="6" Body="&lt;p&gt;Generally meteorologists use mean bias and mean error metrics to characterize the magnitude of their &quot;success&quot; for things like precipitation and wind speed.  Usually a monthly average of performance metrics (or even seasonal) would be used to summarize those results.  Also, it's important to keep in mind that for something like rain, they would be more concerned with the total per day (not the exact time that precip occurred).  Furthermore, keep in mind most weather performance is assessed at airports, where there are weather towers, so they don't assess their predictions over some large area, because they need instrument observations to do so.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2014-05-30T23:16:20.833" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1057" PostTypeId="2" ParentId="1054" CreationDate="2014-05-31T07:26:11.990" Score="7" Body="&lt;p&gt;Firstly, I'd like to state that &lt;em&gt;so far&lt;/em&gt;  there is no evidence that a civilization similar to ours has appeared on Earth before us. It might be apparent that we as a species have left quite a significant geological footprint, (if we didn't Archeologists would be out of a job!), and as of yet we've discovered no evidence to indicate a civilization that cannot be explained by either our species or our close relatives, such as Neanderthals. Also this evidence is completely contained within the last few hundred thousand years (very recent in Geological time). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition for 'eukaryote' life forms to exist (such as humans) oxygen is required so that respiration can occur. If we look at evidence for oxygen in Earth's atmosphere for the majority of it, oxygen is purely a trace element, and simply not enough to sustain complex life forms (as we know it I might add!). This would suggest that not only is there no evidence for complex life forms to exist, there is evidence that complex life forms are simply not possible for most of Earth's history.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Do we have a vast record of fossils and life that is billions of years&#xA;  old?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Essentially, life on Earth before about 540 million years ago (The so called Cambrian 'Explosion') was a little boring, as in it was primary simple multi-cellular organisms that didn't have many hard parts (the bits that get recorded in the fossil record). Think like a sponge today. These kind of life forms have a pretty poor &lt;em&gt;preservation potential&lt;/em&gt; as its called, so before about 550 million years ago the fossil record (in terms of actual fossils) is absolutely terrible.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However we do have existence of life before this time, despite this. For example the &lt;a href=&quot;http://en.wikipedia.org/wiki/Stromatolite&quot; rel=&quot;noreferrer&quot;&gt;Stromatolites&lt;/a&gt; which go back 3.5GA. And while fossils as we think of them today are rare in this period, we have other evidence of life. For example, life has a habit of 'preferentially' uptaking certain isotopes of carbon, meaning that life leaves a so called &lt;em&gt;isotopic signature&lt;/em&gt; in the geological record. These 'signatures' are not direct evidence and are known as 'proxies'. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So essentially we have no evidence of a civilization other than ours existing anywhere in Earth's history, and in fact life itself is pretty boring before about 540 million years ago. &lt;/p&gt;&#xA;" OwnerUserId="389" LastEditorUserId="389" LastEditDate="2014-05-31T21:16:34.860" LastActivityDate="2014-05-31T21:16:34.860" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="1058" PostTypeId="2" ParentId="1054" CreationDate="2014-05-31T08:26:23.890" Score="9" Body="&lt;p&gt;You need to be very wary of anything written in the non-scientific media about science. The media loves woo and controversy because those are the things that garners readers, and that in turn garners advertising revenue.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By way of analogy, suppose as near-adult in gym class someone said &quot;My gym shoes smell bad. Bad! Awfully bad!&quot; Someone else would inevitably take a sniff. If it was bad, really, really bad, he would say so, while gagging. Someone else would say &quot;That bad? Are you sure? Pass it over.&quot; That shoe would have quickly been passed around the locker room if it truly did smell worse than death. (Apologies if you are female; females don't do stupid stuff like this.) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The non-scientific media love scientific articles that smell, particularly those articles that smell extremely bad. The media falls under the compulsion of passing these articles around. Good, solid journalism is sorely lacking nowadays. It's much easier to copy someone else's writing than it is to investigate. It's not plagiarism if the original source receives acknowledgement and a fee. You can typically trace those dubious reports that are all over the internet to a single source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what's the source of this 27 million year recurring extinction event figure? It's two men who keep peddling this conjecture every other year or so. Here's the article that caused this imbroglio:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A. Melott and R. Bambach, &quot;Nemesis reconsidered,&quot; &lt;em&gt;Monthly Notices of the Royal Astronomical Society: Letters&lt;/em&gt;, 407:1 99,102 (2010).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;Rather than looking to the non-scientific media, it is much better to look to the scientific community and see how much credence they have given to this conjecture. The answer is essentially none. That article has received a grand total of seven (CrossRef), maybe nine (Web of Science) citations in the four years it has been in print. The vast majority of those are either self citations or citations by other fringe scientists who are pushing their own brand of woo. This hypothesis is viewed rather lightly by the scientific community.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Moral of the story: Don't believe everything you read on the internet.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Let's suppose your conjecture is true. What signs would we see of a prior civilization? If the civilization was sufficiently advanced we would see a depletion of resources. If that prior civilization had advanced to the stage of sending stuff into space, we wouldn't see iron where we see it now. We see iron in very, very old banded iron deposits. We don't see any anomalous iron deposits in what would have been cities millions and millions of years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same goes for coal and oil. Our first discoveries of oil and coil was stuff easily accessible from the surface. Easy pickings. Those easy pickings would not exist if some prior civilization had advanced to the Elizabethan stage, perhaps even Roman level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What if some calamity had wiped out humanity 2000 years ago? 10,000 years ago? What would a future civilization see millions of years from now? That's a better question. The answer is not much. That future civilization might well not see anything at all. Archaeologists have found fossil records of our ancestors, but that's because we humans are driven to look for those ancestors. A future civilization might not find any fossil humanoids that exhibited a tripling in brain size in just a few million years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That of course is assuming that intelligent life arose before humanity. That too is dubious. Evolution shows a more or less steady progression in brain size. Dinosaurs might not have been as dumb as people thought 50 years ago, but they were still pretty dumb. Their brains were reptilian. Science fiction writers love the idea of intelligent dinosaurs. That's a rather non-standard view amongst scientists.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-05-31T08:26:23.890" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="1059" PostTypeId="2" ParentId="1015" CreationDate="2014-05-31T10:15:38.573" Score="4" Body="&lt;p&gt;Your question is much more complicated from mathematical point of view than it seems to be. First, I'll start with a nice photo:&lt;br/&gt;&lt;img src=&quot;https://i.stack.imgur.com/1y1vG.jpg&quot; alt=&quot;enter image description here&quot;&gt;&#xA;&lt;br/&gt;(source: &lt;a href=&quot;http://en.wikipedia.org/wiki/File:Ho-Mg-ZnQuasicrystal.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;). What you see is really a photo and it is almost a mono-crystal. The only problem is that we all know that it cannot be a monocrystal since it cannot tile the space. So what is it? A quasicrystal -- matter with a well-defined structure, i.e., position of atoms in its quasigrid, yet such one that these positions are not periodic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Speaking of basic cells: This notion is much more complicated for quasicrystals since their basic cells do live in 4-dimensional space, at least from the mathematical point of view. The reason is that a quasicrystal can be modelled as a cut-and-project set. For the one depicted in the figure, this set lives in 4 dimensions.&#xA;If you still insisted on having basic cells, you would need at least two of them, put together in a way similar to &lt;a href=&quot;http://en.wikipedia.org/wiki/Penrose_tiling&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Penrose tiling&lt;/strong&gt;&lt;/a&gt;, which is formed by two different quadrilaterals.&#xA;For more details on mathematical quasicrystals, see for instance &lt;strong&gt;Z. Masáková, J. Patera, J. Zich, &lt;em&gt;Classification of Voronoi and Delone tiles in quasicrystals: I. General method,&lt;/em&gt; J. Phys. A: Math. Gen. 36 (2003) pp. 1869-1894.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To conclude: Your idea that 5-fold symmetry is impossible for a crystal is correct: basically only 3,4 and 6-fold symmetries are possible. For more details, see &lt;a href=&quot;http://en.wikipedia.org/wiki/Crystal_families&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Wikipedia: Crystal families&lt;/strong&gt;&lt;/a&gt;. Still, matters with 5-fold symmetries do exist.&lt;/p&gt;&#xA;" OwnerUserId="99" LastActivityDate="2014-05-31T10:15:38.573" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1060" PostTypeId="1" AcceptedAnswerId="1066" CreationDate="2014-06-01T09:45:06.753" Score="16" ViewCount="5530" Body="&lt;p&gt;Is there any gas/substance which absorbs/reduces atmospheric temperature?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ozone filters UV rays from the sun light and allows in infrared rays. In my knowledge these infrared rays are the cause of the heat. Do we have any provision to block these infrared rays at least for a targeted area? Does any gas or any other substance, natural or human-made, work in this way? &lt;/p&gt;&#xA;" OwnerUserId="536" LastEditorUserId="6467" LastEditDate="2022-07-10T21:21:19.070" LastActivityDate="2022-07-26T01:25:58.700" Title="How to reduce the atmospheric temperature artificially?" Tags="|meteorology|climate-change|geoengineering|" AnswerCount="6" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="1061" PostTypeId="1" CreationDate="2014-06-01T10:50:05.760" Score="13" ViewCount="904" Body="&lt;p&gt;Why doesn't it cleave nicely along the (100) or (010) or any other planes? What determines its cleavage plane? I know it has something to do with the fact that it crystallizes in face centered cubic  system but I don't understand why things happen the way they do.&lt;/p&gt;&#xA;" OwnerUserId="521" LastEditorUserId="156" LastEditDate="2014-06-05T19:11:43.227" LastActivityDate="2022-10-08T00:10:01.550" Title="Why does halite have perfect cleavage at the (110) plane?" Tags="|crystals|mineralogy|crystallography|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="1062" PostTypeId="1" CreationDate="2014-06-01T18:57:17.847" Score="14" ViewCount="284" Body="&lt;p&gt;For a number of gridcells, all between the 500mm and 800mm rainfall isohyets in sub-Saharan Africa, I've got dekadal rainfall (from FEWS).  They are pretty spread out over the continent and there are a lot of them, so they'll have different seasonality, though they should all be roughly unimodal (particularly given the latitudes that I've got).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to define an algorithm to define the average start and end of the rainy season.  So far, I'm thinking of the following:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For each gridcell:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Define the month of average maximum rainfall&lt;/li&gt;&#xA;&lt;li&gt;Find the month prior to the average maximum rainfall month that minimizes the sum of 3 lags of average monthly rainfall, subject to that month containing at least 20% of annual rainfall.  Define it as the average start.&lt;/li&gt;&#xA;&lt;li&gt;Find the month after the average maximum rainfall month that does the same thing, only with 3 forward lags of average monthly rainfall.  Define that month as the end of the rainy season.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The 20% figure seems arbitrary, though I'm not sure what else to do.  I'm not really a climate scientist, though maybe I could play one on television.  Is there an accepted convention here?  If not, any suggestions on improving my algorithm? &lt;/p&gt;&#xA;" OwnerUserId="545" LastEditorUserId="725" LastEditDate="2014-12-04T05:14:07.470" LastActivityDate="2017-06-20T13:34:03.427" Title="How do climatologists define the &quot;start&quot; of a rainy season in a unimodal monsoonal climate?" Tags="|meteorology|climate|precipitation|statistics|climatology|" AnswerCount="1" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1063" PostTypeId="2" ParentId="1060" CreationDate="2014-06-01T19:06:04.390" Score="15" Body="&lt;p&gt;Ozone does not &quot;filter&quot; UV, it absorbs UV radiation (and undergoes some photo-chemistry reactions in the process).  By absorbing those wavelengths it prevents them from reaching us at the surface, but cause a temperature rise in the stratosphere.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We have plenty of gasses that behave this way for terrestrial radiation (however without the photo-chemical reactions).  Some of these gases are $\mathrm{CH_4}$, $\mathrm{CO_2}$ and $\mathrm{H_2 O}$, which we term &lt;em&gt;greenhouse gases&lt;/em&gt; for their ability to readily absorb and radiate at terrestrial (infrared) wavelengths.  If concentrations are high enough, they would reduce some of the infrared spectrum from the sun reaching the surface, but they would also reduce terrestrial emissions into space.  Wherever these gases are doing the absorption one would also experience warming.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you really want to reduce the global temperature solely through radiative forcing, the answer isn't to find and use a gas to absorb infrared radiation.  The answer is to &lt;em&gt;reduce&lt;/em&gt; the concentrations of greenhouse gases in the region you are concerned with.  This will not greatly effect the incoming solar radiation, but it will allow greater radiative losses from the earth and atmosphere (lost to space), resulting in cooling.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You mention that &quot;In my knowledge these infrared rays are the cause the heat&quot;.  While infrared radiation will make you hot (e.g. when the sun shines on your skin), the peak emission from the sun is in the visible spectrum and the primary energy source is in wavelengths shorter than infrared.  This shortwave radiation heats the surface of the Earth which in turn conducts heat to the atmosphere and radiates in the infrared.  Without the presence of greenhouse gases, our planet as is (current albedo, etc) would have a global mean temperature around 255 K, which is quite a bit colder than what we experience with greenhouse gases.  If you want to reduce temperatures, regionally or globally with a gas, your answer is to remove some of them, not add to them.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="1109" LastEditDate="2014-12-04T10:44:06.990" LastActivityDate="2014-12-04T10:44:06.990" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1064" PostTypeId="2" ParentId="1060" CreationDate="2014-06-01T21:00:18.287" Score="8" Body="&lt;p&gt;I think a brief explanation of how the greenhouse effect&lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_radiation_management#Atmospheric_projects&quot;&gt;1&lt;/a&gt; works is in order here.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The light coming from the sun has a broad spectrum, which has its&#xA;peak roughly in the middle of the range that we see as visible light.&#xA;This is probably not a coincidence - it's likely that our eyes&#xA;evolved to use this part of the spectrum because it's the most&#xA;abundant in sunlight.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The atmosphere is largely transparent to visible light - it has to&#xA;be, or surface of the planet would be dark all the time. This&#xA;incoming energy, in the visible spectrum, warms the land and the sea&#xA;during the day.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;All warm objects radiate electromagnetic energy, and the wavelength&#xA;of this energy depends on the temperature of the object. In the case&#xA;of the earth's surface, this temperature corresponds with infra-red&#xA;wavelengths, and so the surface of the planet gives off infra-red&#xA;light. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The atmosphere is much less transparent to infra-red than it is to&#xA;visible light - it is blocked by so-called greenhouse gases.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So the greenhouse effect is caused by this difference in transparency - by the fact that incoming energy, in the visible spectrum, comes straight through the atmosphere, but outgoing energy, in the infra-red spectrum, is stopped from leaving.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, if you wanted to change the composition of the atmosphere to reduce the greenhouse effect, you would either need to make it more opaque to visible light (not recommended, although some people have &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_radiation_management#Atmospheric_projects&quot;&gt;suggested it&lt;/a&gt;), or more transparent to infra-red (which is the aim of all the people who want humanity to reduce its greenhouse gas emissions).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_radiation_management#Atmospheric_projects&quot;&gt;1&lt;/a&gt; And I use the term in its most basic sense, without getting into all the complexities of climate change.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2014-06-01T21:00:18.287" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1065" PostTypeId="1" AcceptedAnswerId="2967" CreationDate="2014-06-02T19:35:33.373" Score="10" ViewCount="8187" Body="&lt;p&gt;I am primarily interested to know:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;What is Norwester (localy called Kalboishaku as because in occurs during the Bengali Month Boishak which falls between Mid April to Mid May).&lt;/li&gt;&#xA;&lt;li&gt;What causes  Norwester.&lt;/li&gt;&#xA;&lt;li&gt;Why does it occur during the month of April and May.&lt;/li&gt;&#xA;&lt;li&gt;Characteristics of Norwesters (What I have personally seen is, it happens during late afternoon with a sudden onset of Cumulonimbus cloud spreading across within few minutes followed by heavy thunderstorm and rain which persists for an hour followed by clear sky)&lt;/li&gt;&#xA;&lt;li&gt;What are the areas affected by Norwesters. (I am only aware of the east Gangetic plane)&lt;/li&gt;&#xA;&lt;li&gt;Why it is called Norwesters (My guess is its because the wind blows from North West)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Note&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are very little information around currently on Norwesters and even the &lt;a href=&quot;http://en.wikipedia.org/wiki/Norwesters&quot;&gt;wiki page&lt;/a&gt; is a stub. Most of my contextual answers are based on my experience with Norwesters but I couldn't find any studies or articles in this regard. I am possibly looking for answers drawn from credible source (possible links to journals/ books / papers), as this would be a nice opportunity to build a credible wiki on this subject.&lt;/p&gt;&#xA;" OwnerUserId="547" LastEditorUserId="39" LastEditDate="2014-06-05T12:20:55.733" LastActivityDate="2014-12-06T11:56:08.293" Title="What is the primary cause of the &quot;Norwester&quot; winds that affect parts of India &amp; Bangladesh?" Tags="|weather|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1066" PostTypeId="2" ParentId="1060" CreationDate="2014-06-02T23:11:32.257" Score="6" Body="&lt;p&gt;Typically temperature reductions in localized regions are not due to reduction of greenhouse gases.  Greenhouse gases are well mixed and long lived and so reducing their concentrations has more of a regional or global affect.  For a &quot;tageted area&quot; you would want to introduce aerosols into the atmosphere (e.g. clouds) so that the incoming light is reflected before it reaches the surface.  Alternatively, you could change the albedo of the surface so that it is mostly white, thereby increasing reflection of visible light at the surface and reducing absorption (which in turn reduces infrared radiation from the surface of the Earth).&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2014-06-02T23:11:32.257" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="1067" PostTypeId="2" ParentId="17" CreationDate="2014-06-02T23:27:09.240" Score="2" Body="&lt;p&gt;Temperature is a measure of kinetic energy which, in the atmosphere, is due to the number of molecules and their speed.  There is less atmosphere at higher altitudes (e.g. lower pressure, less molecules), so a measure of temperature will be lower there because less molecules are moving around. That is the fundamental/basic reason that temperature is lower at higher altitudes in the troposphere.  Furthermore, since there are a smaller number of greenhouse gas molecules trapping energy, more heat is lost to space at higher altitudes.  &lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2014-06-02T23:27:09.240" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="1068" PostTypeId="1" CreationDate="2014-06-03T12:48:25.420" Score="10" ViewCount="147" Body="&lt;p&gt;I've been doing a bit of reading about the formation of the moon, and I've found multiple references (&lt;a href=&quot;http://naca.larc.nasa.gov/search.jsp?R=20000000512&amp;amp;qs=N=4294950110%2b4294961259%2b4294939825&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;http://serc.carleton.edu/NAGTWorkshops/structure/enigmas.html&quot;&gt;2&lt;/a&gt;, &lt;a href=&quot;http://www.astro.washington.edu/users/solontoi/BCC/slides/SolarSystem_moon_3.pdf&quot;&gt;3&lt;/a&gt;) to something called Taylor's axiom, stated in link (3) above as:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The best models for lunar origin are the testable ones.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A few related questions:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Who came up with it? If it was, in fact, someone named Taylor (&lt;a href=&quot;http://en.wikipedia.org/wiki/Stigler%27s_law_of_eponymy&quot;&gt;which it need not be&lt;/a&gt;), which Taylor?&lt;/li&gt;&#xA;&lt;li&gt;Is there a paper/talk/etc that contains a definitive form of Taylor's axiom? &lt;/li&gt;&#xA;&lt;li&gt;I think we can all agree that testable models are the best ones. Why, then, did Taylor's axiom even need to be stated? e.g. was there a time when when &lt;em&gt;untestable&lt;/em&gt; theories of lunar formation were in vogue or something?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="67" LastEditorUserId="725" LastEditDate="2014-12-04T05:15:20.813" LastActivityDate="2022-08-05T03:56:11.783" Title="Who originated Taylor's axiom of lunar formation, and where?" Tags="|earth-history|moon|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1069" PostTypeId="2" ParentId="1068" CreationDate="2014-06-03T13:01:23.790" Score="4" Body="&lt;p&gt;Just a shot in the dark, as the journal in which this article has been published has no online presence and is not available in paper form in my institution, but it might refer to an article by a Richard L. S. Taylor from 1990 called &lt;a href=&quot;http://adsabs.harvard.edu/abs/1990Space...6...36T&quot; rel=&quot;nofollow&quot;&gt;'The Damocles Hypothesis'&lt;/a&gt;, published in the journal &quot;Space&quot; (journal edited by the University of London it seems). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Follows the abstract of that article:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Consideration is given to the use of data from the Apollo missions to&#xA;  study theories of the origin and geological evolution of the moon.&#xA;  Theories of lunar origin are examined, including origin by fission,&#xA;  binary accretion origin, the capture hypothesis, and the giant impact&#xA;  model. Apollo data related to each of these theories is summarized,&#xA;  showing that the giant impact model is the most probable theory for&#xA;  the origin of the moon. The giant impact model is outlined, focusing&#xA;  on the collision between the earth and a large body called Damocles.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-06-03T13:13:11.547" LastActivityDate="2014-06-03T13:13:11.547" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1070" PostTypeId="2" ParentId="8" CreationDate="2014-06-03T19:13:53.977" Score="12" Body="&lt;p&gt;Most data we collect about weather is done regularly and for all altitudes of the troposphere.  Kites, though, are at the mercy of the weather and do not fly high enough.  So when there is ice or snow or other meteorological conditions that don't allow a kite to fly, you get no data.  We now use methods to measure the weather that don't break in bad weather.  The answer to your question is succinctly put in this &lt;a href=&quot;http://www.ua.nws.noaa.gov/reqdahdr.htm&quot; rel=&quot;noreferrer&quot;&gt;NOAA webpage&lt;/a&gt; where they state these difficulties with kites: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The average altitude reached was only about 3 km.&lt;/li&gt;&#xA;&lt;li&gt;Data could not be evaluated until after the kite was reeled in...&lt;/li&gt;&#xA;&lt;li&gt;Observations could only be taken in good weather with winds neither too light or too strong.&lt;/li&gt;&#xA;&lt;li&gt;There was danger of the kite breaking away and endangering lives and property.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In the 1940s, weather balloons were being released and could gather an entire profile of data in all weather conditions.  This is far superior to a kite.  That being said, some people do still use kites: &lt;a href=&quot;http://www.phschool.com/science/science_news/articles/high_flying.html&quot; rel=&quot;noreferrer&quot;&gt;High-Flying Science, with Strings Attached.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="6093" LastEditDate="2016-07-14T01:20:59.017" LastActivityDate="2016-07-14T01:20:59.017" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="1071" PostTypeId="2" ParentId="934" CreationDate="2014-06-03T19:20:11.607" Score="6" Body="&lt;p&gt;Without spin-up time, our initial conditions would be blank or generic. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I guess the simple answer is &quot;NO&quot; spin-up time is not really affected by the resolution, unless the model resolution changes are so great that it takes much longer for diffusion / advection between cells to flush out. Though that wouldn't explain a 5 year change in spin up time unless you made drastic changes to a model with very large time steps. Increased model resolution could theoretically increase the necessary spin-up time by a small amount, if the changes in resolution were very large and the time steps used were coarse.   However, in a reputable research setting the spin up time is chosen based on how long (in model time) it takes for things to get to an acceptable initial condition, and changes in resolution are usually not so extreme.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Complexities in the model can increase desirable spin-up time if they have long time-horizons before an acceptable initial condition is achieved.  The spin-up time you choose for your model will influence the degree to which the initial conditions actually represent a realistic distribution of numerics across all parameters, assuming the model is adequately developed.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2014-07-19T03:31:21.043" LastActivityDate="2014-07-19T03:31:21.043" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="1072" PostTypeId="2" ParentId="888" CreationDate="2014-06-03T20:23:44.093" Score="8" Body="&lt;p&gt;The average global warming due to greenhouse gases corresponds to a 33 Kelvin temperature increase.  If you remove all greenhouse gases the average global temperature would then decrease 33 Kelvin (from 288K to 255K).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might want to check out:&#xA;&lt;a href=&quot;http://www.nasa.gov/topics/earth/features/co2-temperature.html&quot; rel=&quot;nofollow&quot;&gt;http://www.nasa.gov/topics/earth/features/co2-temperature.html&lt;/a&gt;&#xA; which estimates the CO&lt;sub&gt;2&lt;/sub&gt; portion of global warming to be about 80%.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;... it is the 25 percent non-condensing greenhouse gas component, which includes carbon dioxide, that is the key factor in sustaining Earth’s greenhouse effect. By this accounting, carbon dioxide is responsible for 80 percent of the radiative forcing that sustains the Earth’s greenhouse effect.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Simple math might suggest then that the average global temperature of Earth would be ~262K if CO&lt;sub&gt;2&lt;/sub&gt; were completely removed.  There are always sources of CO&lt;sub&gt;2&lt;/sub&gt; though, so you could never remove it all as it is constantly being replenished when animals breathe and things burn.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2015-08-31T23:15:39.333" LastActivityDate="2015-08-31T23:15:39.333" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="1073" PostTypeId="1" CreationDate="2014-06-04T00:54:38.957" Score="11" ViewCount="1550" Body="&lt;p&gt;I'm currently learning how to identify rocks in hand specimen. The initial classification into igneous, metamorphic, and sedimentary is mostly ok, but I'm having a problem with further identifying sedimentary rocks—I don't know how to tell if they're calcareous or siliceous without using HCl, which seems somewhat impractical to use on every sedimentary rock I see. Is there any good way of telling?&lt;/p&gt;&#xA;" OwnerUserId="551" LastActivityDate="2016-03-22T15:47:18.487" Title="Identifying sedimentary rocks in hand specimen" Tags="|sedimentology|rocks|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1074" PostTypeId="2" ParentId="11" CreationDate="2014-06-04T13:45:08.163" Score="6" Body="&lt;p&gt;Since you're asking about Pangaea time, i would assume you're talking about the Permian (from 299Ma to 252 Ma).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We have a good idea of what Permian paleogeography was, a fair idea of how Permian oceans circulated globally (see &lt;a href=&quot;https://earthscience.stackexchange.com/a/83/87&quot;&gt;one of your previous questions&lt;/a&gt;), enough data to produce credible models on how was the climate at the time (see e. g. &lt;strong&gt;Gibbs et al. 2002&lt;/strong&gt;), even some idea on what atmospheric circulation (see e. g. &lt;strong&gt;Tibor &amp;amp; Montanez 2002&lt;/strong&gt;) was like during that Period. So in theory i don't see any major hurdles to model these kind of oscillations (keep in mind that i am not a climate model specialist).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now in my opinion, the big issue would be the data to back the model on, and particularly the time resolution needed to study these kind of oscillations: ENSO, PDO, NAM, SAM etc are annual to decadal oscillations (1-10yr).&lt;br&gt;&#xA;A resolution &quot;commonly&quot;-achieved so far in detecting climatic oscillations in the Permian fossil record is for cycles of ca. 20kyr (i. e. 20 000 years; Milankovitch precession cycle). The kind of sedimentation rates and sediment quality needed to be able to record annual layers are extremely rare for such older sediments.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With that in mind, it's not impossible to find such sediments, in fact &lt;strong&gt;Anderson (1982)&lt;/strong&gt; detailed the 260kyr-long continuous, annual varved Castille and Bell Canyon Permian evaporitic Formations, but even in such a high-resolution formation the shorter-length oscillation detected was still at ca. 180yr so way above that of any of the annular modes you mentioned.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;References:&lt;br&gt;&#xA;Anderon, R. Y., 1982. &lt;a href=&quot;http://dx.doi.org/10.1029/JC087iC09p07285&quot; rel=&quot;nofollow noreferrer&quot;&gt;A long geoclimatic record from the Permian&lt;/a&gt;. Journal of Geophysical Research : Oceans, 87: 7285-7294.&lt;br&gt;&#xA;Gibbs, M. T., McAllister Rees, P., Kutzbach, J. E., Ziegler, A. M., Behling, P. J., Rowley, D. B., 2002. &lt;a href=&quot;http://dx.doi.org/10.1086/324204&quot; rel=&quot;nofollow noreferrer&quot;&gt;Simulations of Permian Climate and Comparisons&#xA;with Climate-Sensitive Sediments&lt;/a&gt;. Journal of Geology, 110: 33-55.&lt;br&gt;&#xA;Tibor, N. J., Montanez, I. P., 2002. &lt;a href=&quot;http://geology.gsapubs.org/content/30/12/1127.short&quot; rel=&quot;nofollow noreferrer&quot;&gt;Shifts in late Paleozoic atmospheric circulation over western equatorial Pangea: Insights from pedogenic mineral $\delta^{18}O$ compositions&lt;/a&gt;. Geology, 30: 1127-1130.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-06-04T13:45:08.163" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1075" PostTypeId="1" AcceptedAnswerId="1081" CreationDate="2014-06-04T21:01:48.303" Score="13" ViewCount="170" Body="&lt;p&gt;I am attempting to develop variable names following Unidata's climate forecasting (CF) variable naming guidelines, but for biological variables used to parameterize and evaluate land surface and ecosystem models (&lt;a href=&quot;https://docs.google.com/spreadsheet/ccc?key=0Ai_PDCcY5g2JdEZoSW5KYks1ZHRSdHJIbndoRl8wdWc&amp;amp;usp=sharing#gid=0&quot; rel=&quot;noreferrer&quot;&gt;See a first draft on Google drive&lt;/a&gt;). However, I can not find the documentation for these guidelines. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Until early 2014, the guidelines were here: &lt;a href=&quot;http://cf-pcmdi.llnl.gov/&quot; rel=&quot;noreferrer&quot;&gt;http://cf-pcmdi.llnl.gov/&lt;/a&gt;, but now there is a link to &lt;a href=&quot;http://cfconventions.org/&quot; rel=&quot;noreferrer&quot;&gt;http://cfconventions.org/&lt;/a&gt;, and then a &lt;a href=&quot;http://cfconventions.org/standard-names-26.html&quot; rel=&quot;noreferrer&quot;&gt;list of standard names&lt;/a&gt;, but the &lt;a href=&quot;http://cf-pcmdi.llnl.gov/documents/cf-standard-names/guidelines&quot; rel=&quot;noreferrer&quot;&gt;guidelines page&lt;/a&gt; that this points to does not (currently) exist. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think it would be helpful here to have a link to the appropriate documentation, but also a summary of the guidelines (i.e., how to construct variable names that are consistent with the CF approach). In addition, any feedback on the standard_name field in my draft would be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="174" LastEditorUserId="284" LastEditDate="2014-06-05T20:26:13.263" LastActivityDate="2014-06-06T15:45:59.710" Title="What are the guidelines for constructing variable names that follow CF conventions?" Tags="|models|terminology|cf-metadata|" AnswerCount="2" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1076" PostTypeId="1" AcceptedAnswerId="2093" CreationDate="2014-06-05T10:16:33.783" Score="27" ViewCount="3603" Body="&lt;p&gt;I know it depends on the type of snow (dry or wet) and the rougness of the surface. I'm looking for an approximate rule of thumb answer. Assuming a reasonably smooth surface, at what angle it's likely to be free from snow?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Google results only discuss snow and slopes in context of skiing and roofs not caving in. Obviously, a snow safe roof (60+ degrees) will still accumulate a few inches of snow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, imagine a &lt;a href=&quot;http://www.locationequipmentsupply.com/img/products/LES-0078-L-On-Location-47Sandwich-Board-Sign-Blank.jpg&quot;&gt;sandwitch board&lt;/a&gt; sign. What's the minimum &quot;uprightness&quot; for it to not get obscured by snow and stay readable throughout the year?&lt;/p&gt;&#xA;" OwnerUserId="553" LastEditorDisplayName="user12525" LastEditDate="2019-04-17T09:51:09.327" LastActivityDate="2021-12-08T12:25:27.500" Title="What is the steepest surface that can hold snow?" Tags="|meteorology|atmosphere|snow|" AnswerCount="4" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="1077" PostTypeId="1" AcceptedAnswerId="1078" CreationDate="2014-06-05T13:19:24.380" Score="11" ViewCount="2329" Body="&lt;p&gt;What are the criteria to determine if river A is a major or minor tributary to another River B?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is stream order the only deciding factor i.e. the highest order is the main stem, one less order is a major tributary and one more lesser order is a minor tributary?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I haven't been able to find any literature on this online.&lt;/p&gt;&#xA;" OwnerUserId="554" LastEditorUserId="81" LastEditDate="2014-06-05T17:17:01.303" LastActivityDate="2014-06-05T17:17:01.303" Title="How are minor tributaries of a river determined?" Tags="|hydrology|rivers|geomorphology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="1078" PostTypeId="2" ParentId="1077" CreationDate="2014-06-05T16:00:12.273" Score="10" Body="&lt;p&gt;This is a question of topology. There are three major attempts to order streams from small to larger. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first was established by &lt;a href=&quot;http://www.sages.ac.uk/home/homes/s0451705/horton_1945.pdf&quot; rel=&quot;noreferrer&quot;&gt;Horton (1941)&lt;/a&gt; who established the concept of &lt;em&gt;drainage composition&lt;/em&gt;. To establish the relative importance of streams in a network Horton suggested to investigate each junction and to set the stream that entered the junction at the highest angle as a stream of lower importance. By starting at the mouth of a river, one can thus establish which would be the main trunk of a river and which are tributaries of smaller and smaller significance. The order number of streams cannot be determined until the entire tree of streams have been ordered. In the figure on Strahler stream order the diagonal would be the main trunk of the river and have order three. The only order two trunk would be the one labelled two turning down from three in the figure. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://gsabulletin.gsapubs.org/content/63/11/1117&quot; rel=&quot;noreferrer&quot;&gt;Strahler, 1952&lt;/a&gt; took the concept further and established the concept of &lt;em&gt;stream order&lt;/em&gt;. In this approach the basic stream is the smallest source tributaries. When two streams of order one meet they form a stream of order two. It takes two of the same order to make a stream of a larger order so a stream of order two and one will not increase the order number, the result is still two. The following image provides an example of Strahler's stream order:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/yUxbw.png&quot; alt=&quot;Strahler stream order&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Strahler stream order concept. Image from Wikipedia commons&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The stream order allows one to calculate an assortment of statistical measures that characterizes a drainage basin and it is possible to use these characteristics in, for example, flood prediction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shreve (1967) took the ideas of Horton and Strahler further by introducing magnitude, now called &lt;em&gt;Shreve Magnitude&lt;/em&gt;. This concept differs from Strahler's in that all streams are additive so that as soon as one stream is added to another the resulting stream is the sum of the two tributaries. The result is that the system can be seen as reflecting discharge, assuming all first order streams are of similar size. In the figure above the largest magnitude would be six, this is also the sum of all order one streams.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So establishing the main trunk of a river is not necessarily simple. Hortons method does this but is at the same time relying on geometry and rivers may be heavily influenced by geology  to generate odd river patterns.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;References&lt;/em&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Horton, R.E., 1945. Erosional development of streams and their drainage basins: Hydrophysical approach to quantitative morphology. &lt;em&gt;Geological Society of America Bulletin&lt;/em&gt;, 56, 275-370. doi: 10.1130/0016-7606(1945)56[275:EDOSAT]2.0.CO;2&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shreve, R.L., 1967. Infinite topologically random channel networks. &lt;em&gt;Journal of Geology&lt;/em&gt; 75, 178–186.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Strahler, A.N., 1952. Hypsometric (area-altitude) analysis of erosional topology. &lt;em&gt;Geological Society of America Bulletin&lt;/em&gt;, 63 (11), 1117–1142, doi:10.1130/0016-7606(1952)63[1117:HAAOET]2.0.CO;2.&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2014-06-05T16:00:12.273" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1079" PostTypeId="2" ParentId="1073" CreationDate="2014-06-05T16:37:44.727" Score="2" Body="&lt;p&gt;Two approaches:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Hardness. Which mineral will scratch the glass plate?&lt;/li&gt;&#xA;&lt;li&gt;General look. Can you see any microfossils? &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Use HCL to confirm your intuition.&lt;/p&gt;&#xA;" OwnerUserId="48" LastEditorUserId="156" LastEditDate="2014-06-05T19:11:41.033" LastActivityDate="2014-06-05T19:11:41.033" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1080" PostTypeId="2" ParentId="1073" CreationDate="2014-06-05T18:19:00.977" Score="9" Body="&lt;p&gt;When learning to distinguish between siliceous and calcareous samples you should use a handlens.  Look for quartz, feldspars or micas.  Quartz clasts may be frosted, or you may be able to see conchoidal fracture.  Calcite will be very soft compared to both feldspar and quartz, and should fail to scratch copper (or at least not scratch it very well, while a quartz rich sedimentary hand sample will scratch glass.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For really fine grained stuff, there are times when you may need to use the context of site where the sample is from if you don't have HCL.  There can be sedimentary rocks that are made up of siliceous clasts that react with HCL due to calcite in the matrix, so HCL can be misleading.  I've even found that some mudstones and limestones can have an organic odor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lastly, there are structures that can suggest if a sample is siliceous or calcareous.  Styolites would suggest non-siliceous while thermal alterations like liesegang banding would suggest siliceous.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The more samples you tackle, the easier it gets.&lt;/p&gt;&#xA;" OwnerUserId="156" LastEditorUserId="156" LastEditDate="2014-06-05T18:24:26.210" LastActivityDate="2014-06-05T18:24:26.210" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="1081" PostTypeId="2" ParentId="1075" CreationDate="2014-06-05T20:22:22.153" Score="8" Body="&lt;p&gt;Possible this is not what you need, but here's an archive of the &lt;a href=&quot;https://web.archive.org/web/20130728212039/http://cf-pcmdi.llnl.gov/documents/cf-standard-names/guidelines&quot; rel=&quot;noreferrer&quot;&gt;Guidelines for Construction of CF Standard Names&lt;/a&gt;, which is &quot;Version 1, 3 December 2008&quot; and was cached on July 28, 2013; guessing that the page has not been updated since December 2008.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, the source code repository for CF Conventions website you linked to (&lt;a href=&quot;http://cf-convention.github.io&quot; rel=&quot;noreferrer&quot;&gt;cf-convention.github.io&lt;/a&gt;) is viewable from &lt;a href=&quot;https://github.com/cf-convention&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;; if you had questions about the status of the site, you might try contacting the &lt;a href=&quot;https://github.com/mattben&quot; rel=&quot;noreferrer&quot;&gt;developer listed on Github for the project&lt;/a&gt;; &lt;a href=&quot;https://github.com/mattben&quot; rel=&quot;noreferrer&quot;&gt;their email is listed on their Github profile&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE:&lt;/strong&gt; Here's the &lt;a href=&quot;http://home.badc.rl.ac.uk/apamment/&quot; rel=&quot;noreferrer&quot;&gt;contact info for the CEDA Data Scientist&lt;/a&gt;; their &quot;main role in CEDA is the development of metadata standards, particularly the CF (Climate and Forecast) metadata conventions.&quot;&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="284" LastEditDate="2014-06-06T13:51:49.020" LastActivityDate="2014-06-06T13:51:49.020" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="1082" PostTypeId="2" ParentId="1034" CreationDate="2014-06-05T23:10:18.690" Score="5" Body="&lt;p&gt;I'm pretty sure a more rigorous answer deserves to come along, but I can give a simple overview of some of the important factors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cleavage planes have to do with bond strength and bond geometry.  If there isn't a plane of bonds that can be cut through, then you won't get cleavage.  When a mineral is fractured, the fracture &quot;wants&quot; to take the path where the total energy required to break all of the bonds along that path is at a minimum.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Halite, you can &quot;cleave&quot; a perfect plane through weaker ionic bonds (the geometry works, and the bonds are weak).  In quartz, all of the bonds are of the same strength (strong silicate bonds), and the geometry of the mineral is such that you can not find a plane that will cut through all of the bonds, therefore the fractures must &quot;wander&quot; creating the conchoidal structures.  In mica, the cleavage planes form between the silicate sheets.  The silica bonds are strong, the the sheets are held together by weaker ionic bonds.&lt;/p&gt;&#xA;" OwnerUserId="156" LastActivityDate="2014-06-05T23:10:18.690" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="1083" PostTypeId="2" ParentId="99" CreationDate="2014-06-06T09:19:11.057" Score="4" Body="&lt;p&gt;There is an alternative theory that the Earth's magnetic field is due to ocean currents since the sea contains (charged) dissolved salts. The flipping of the poles would then presumably be due to a major change in the currents. From what I have read there is a great deal of uncertainty about this subject.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://physicsworld.com/cws/article/news/2009/jun/14/earths-magnetic-field-perturbed-by-electric-oceans-claims-researcher&quot; rel=&quot;nofollow&quot;&gt;Physics world article&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user231" LastEditorUserId="6" LastEditDate="2014-06-06T19:49:07.723" LastActivityDate="2014-06-06T19:49:07.723" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="1084" PostTypeId="1" AcceptedAnswerId="2309" CreationDate="2014-06-06T11:25:14.947" Score="18" ViewCount="5387" Body="&lt;p&gt;Taste can be used to distinguish halite (ordinary salt) from sylvite (which has some bitterness) and siltstone from mudstone (the latter has a creamy texture while the grains of the former can be felt). Are there other uses of taste for identification?&lt;/p&gt;&#xA;" OwnerDisplayName="user26" LastEditorDisplayName="user26" LastEditDate="2014-06-06T12:33:31.977" LastActivityDate="2015-06-09T07:18:34.643" Title="When can taste be used to help identify rocks?" Tags="|geology|petrology|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="1085" PostTypeId="1" AcceptedAnswerId="2095" CreationDate="2014-06-06T14:32:21.457" Score="11" ViewCount="815" Body="&lt;p&gt;I am trying to set up a coastal ocean model simulation. I am looking for different ways to force the tidal boundary condition in the model to study how uncertainty in the tidal forcing in the boundary affects the model solution. What are the different tidal databases that people are currently using?&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2016-09-04T17:12:19.757" Title="What tidal databases are available to be used as model boundary conditions?" Tags="|ocean|oceanography|models|tides|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="1086" PostTypeId="2" ParentId="1075" CreationDate="2014-06-06T15:00:17.887" Score="7" Body="&lt;p&gt;As a result of @blunders answer, I located the document, and will summarize here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The general framework for constructing names is:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;[surface] [component] standard_name [at surface] [in medium] [due to process] [assuming condition]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;where &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;surface&lt;/strong&gt; is a horizontal plane, e.g. &lt;code&gt;tropopause&lt;/code&gt;, or &lt;code&gt;sea_level&lt;/code&gt;. &#xA;&lt;ul&gt;&#xA;&lt;li&gt;Single word surface names go at the beginning; surfaces with more than one name goes after the standard_name&lt;/li&gt;&#xA;&lt;li&gt;&lt;code&gt;tropopause_stuff&lt;/code&gt; &lt;/li&gt;&#xA;&lt;li&gt;&lt;code&gt;stuff_at_sea_level&lt;/code&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;component&lt;/strong&gt; is a vector, e.g. &lt;code&gt;upward&lt;/code&gt;, &lt;code&gt;northward&lt;/code&gt;, &lt;code&gt;x&lt;/code&gt;, etc. &lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;medium&lt;/strong&gt; is, e.g. in_water, in_soil, etc.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;process&lt;/strong&gt; starts with &quot;due_to&quot;, e.g. &lt;code&gt;due_to_longwave_heating&lt;/code&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;assuming condition&lt;/strong&gt; is a conditional assumption, e.g. &lt;code&gt;assuming_clear_sky&lt;/code&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Other conventions: there are a number of further conventions provided to standardize meaning, e.g. in the construction of standard_names when transformations, special phrases, chemical species, or generic names are used. For example,&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;transformations imply a particular form of units, e.g &lt;code&gt;ratio_of_X_to_Y&lt;/code&gt; implies a specific form for the units (in this case &lt;code&gt;[x]/[Y]&lt;/code&gt;.&lt;/li&gt;&#xA;&lt;li&gt;generic names imply specific units, e.g. &lt;code&gt;amount&lt;/code&gt; implies &lt;code&gt;kg/m2&lt;/code&gt;, &lt;code&gt;area&lt;/code&gt; implies &lt;code&gt;m2&lt;/code&gt;, etc.&lt;/li&gt;&#xA;&lt;li&gt;there are standard spellings for chemical species, e.g. &lt;code&gt;nitrate&lt;/code&gt;, &lt;code&gt;carbon_dioxide&lt;/code&gt;&lt;/li&gt;&#xA;&lt;li&gt;phrases: &lt;code&gt;water&lt;/code&gt; refers to H$_2$O in all phases; &lt;code&gt;wrt&lt;/code&gt; = with respect to, &lt;code&gt;toa&lt;/code&gt; = top of atmosphere, etc.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="174" LastEditorUserId="174" LastEditDate="2014-06-06T15:45:59.710" LastActivityDate="2014-06-06T15:45:59.710" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1087" PostTypeId="2" ParentId="894" CreationDate="2014-06-06T19:27:49.543" Score="3" Body="&lt;p&gt;I'm not sure that record temperatures occur with enough frequency that we can attribute them to this specific phenomena, though I am no authority on records.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think that attaining a record high with warm frontal passage is unlikely.  As you mention, the warm front is often accompanied by cloudy weather, and these clouds first manifest as high cirrus clouds well poleward of the surface front, lowering closer to the front.  This combined with possible precipitation will moderate the temperatures.  If rain is falling on the cold side of the front prior to frontal passage (FROPA) it will likely stabilize at the wet-bulb and stay far from the record temperatures.  Places on the warm side, if experiencing precipitation will have a similar experience and probably not near high temperatures.  You may have a case here for potentially warmer night temperatures, but I'm not sure you'll be in record territory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A better case for potential high temperatures can be just prior to cold frontal passage.  Especially for a strong cold front, the pressure gradient can drive strong southerly flow (in the NH) bringing lots of warm air advection ahead of the front.  If you watch a temperature trace before such FROPA you'll see a sharp rise in temperature before it plummets. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Typical FROPA probably won't set records.  You need some exceptional aspect of it or at least some unseasonable occurance to really threaten the records.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Though I was unable to justify it with data, I do not suspect warm frontals are a common source of high temperature records (high daily max or high daily low).&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-06-06T19:27:49.543" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1089" PostTypeId="1" AcceptedAnswerId="2097" CreationDate="2014-06-07T20:13:47.243" Score="13" ViewCount="820" Body="&lt;p&gt;As in ice core data shows that $CO_2 $ levels have fluctuated on levels correlating to the temperature and ice levels, but I couldn't think of a mechanism for what might be the link between the release of carbon dioxide and other gases, and presumably orbital geometry? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it to do with gases dissolved in the oceans? Or the melting of permafrost?&lt;/p&gt;&#xA;" OwnerUserId="389" LastEditorUserId="44" LastEditDate="2014-06-09T13:49:03.803" LastActivityDate="2014-12-05T07:16:20.583" Title="Carbon Dioxide levels appear to be linked to the Milankovitch cycles according to Ice Core data but what is the mechanism?" Tags="|climate|ice-age|milankovitch-cycles|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1090" PostTypeId="2" ParentId="934" CreationDate="2014-06-08T01:43:29.943" Score="5" Body="&lt;p&gt;I would say that the biggest factor influencing spin-up time is whether the model includes a dynamically-coupled ocean component. A regional or even global atmosphere-only model, with a realistic initial state and forced by realistic boundary conditions, will reach equilibrium pretty quickly; certainly a decade or less. An ocean model may not reach equilibrium even after a thousand years, and in fact this can be seen in many of the CMIP5 model control runs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's probably also worth pointing out that while model drift is often attributed to incomplete spin-up in coupled models, often drift is more due to some kind of spurious energy 'leakage' in the model's energy balance, which the ocean component acts to restore. In this case, the model will never reach an equilibrium, 'drift free' state.&lt;/p&gt;&#xA;" OwnerUserId="344" LastActivityDate="2014-06-08T01:43:29.943" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1091" PostTypeId="1" CreationDate="2014-06-08T09:48:25.797" Score="11" ViewCount="235" Body="&lt;p&gt;Under climate change scenarios, it is quite certain that high latitude regions will experience more warming than at low latitudes. For example, in winter the reduced area of sea ice and snow cover should have the amplifying effect for temperature rising over polar region. Thus the meridional temperature gradient would also be reduced, so as the baroclinicity. Baroclinicity is important in theories concerning synoptic weather forecast in mid-latitudes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there an estimate, and if yes how much climate change will reduce synoptic weather predictability? How will predictability be affected in springtime for mid-latitudes?&lt;/p&gt;&#xA;" OwnerUserId="476" LastEditorDisplayName="user889" LastEditDate="2014-12-08T20:34:56.113" LastActivityDate="2017-01-11T06:41:28.487" Title="Synoptic weather predictibility under climate change scenarios" Tags="|meteorology|atmosphere|climate-change|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1092" PostTypeId="1" AcceptedAnswerId="1094" CreationDate="2014-06-08T11:01:12.537" Score="21" ViewCount="24061" Body="&lt;p&gt;I am looking for historical hourly temperature data from many cities in the US what other data sources are there except &lt;a href=&quot;http://www.wunderground.com/history/&quot;&gt;wunderground&lt;/a&gt;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE:&lt;/strong&gt; I will use the data to compare stations from the same city and need data with high temporal &amp;amp; spatial resolution; currently, one year of data is enough. I am not mentioning a specific US city because I need data from as many cities in the US as possible that meet my requirements. I am working on a big project of forecasting and I want to see the spatial deviations with in many large cities in the US.&lt;/p&gt;&#xA;" OwnerUserId="83" LastEditorUserId="284" LastEditDate="2014-06-08T16:32:39.550" LastActivityDate="2022-09-11T21:03:03.477" Title="Where can I get archived hourly temperature data?" Tags="|meteorology|climate|temperature|open-data|database|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="1094" PostTypeId="2" ParentId="1092" CreationDate="2014-06-08T16:14:06.910" Score="15" Body="&lt;p&gt;The authoritative sources for your data are:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;ASOS: &lt;a href=&quot;http://www.nws.noaa.gov/asos/&quot;&gt;Automated Surface Observation Systems&lt;/a&gt; at airports, and&lt;/li&gt;&#xA;&lt;li&gt;MADIS:  the &lt;a href=&quot;http://madis.noaa.gov/&quot;&gt;Meteorological Assimilation Data Ingest System&lt;/a&gt;, from NOAA&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Those are collections based on calibrated, maintained equipment, with good geographic coverage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And Wunderground already archives them, so it's a matter of selecting and using those, rather than the &lt;a href=&quot;http://www.wunderground.com/about/data.asp&quot;&gt;Wunderground data&lt;/a&gt; from their own source, the collection of personal weather stations.&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="100" LastEditDate="2014-06-08T16:23:50.163" LastActivityDate="2014-06-08T16:23:50.163" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2093" PostTypeId="2" ParentId="1076" CreationDate="2014-06-08T19:02:21.063" Score="17" Body="&lt;p&gt;An object on an angular surface will fall off, when forces exerted along the slope (gravitational, tangent to the surface: gt) are greater then those pressing the object to the slope (gravitational, perpendicular to the slope, gp) or working in the opposite direction on the slope (friction, $fr$).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an example, $10\ \mathrm{cm}$ of snow, on a 0.5-by-1-meter surface:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$0.1 \times 0.5 \times 1 = 0.05\ \mathrm{m^3}$ of snow, weighing approximately $0.05 \ \mathrm{m^3}\times 300\  \mathrm{\dfrac{kg}{m^3}}$ (density of snow = $300\ \mathrm{\dfrac{kg}{m^3}}$) = $15\ \mathrm{kg}$.&lt;/li&gt;&#xA;&lt;li&gt;Gravitational force exerted = $9.81\  \mathrm{\dfrac{m}{s^2}} \times 15\ \mathrm{kg} = 147\ \mathrm{N}$.&lt;/li&gt;&#xA;&lt;li&gt;Frictional force $fr = 147\ \mathrm{N}\times 0.53$ (as a lower bound guess, see &lt;a href=&quot;http://arc.lib.montana.edu/snow-science/objects/issw-2002-523-527.pdf&quot; rel=&quot;noreferrer&quot;&gt;link&lt;/a&gt;) = $77.91\ \mathrm{N}$.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The snow will fall off if $gp &amp;gt; fr$, and this occurs at an angle of $\arcsin{\dfrac{fr}{gp}} = 32^{\circ}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recalculating for the high bound friction coefficient ($1.76$), results in the snow not even falling off if the surface were vertical.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think you already pointed out the biggest problem: any estimate is heavily dependent on the contact surface, type of snow and other conditions (temperature, wind, etc.). I haven't done a thorough looking around, but from the friction coefficients listed in this one article, I can only guess that you'll have a wide variety of ranges, making a rule of thumb difficult.&lt;/p&gt;&#xA;" OwnerUserId="446" LastEditorUserId="725" LastEditDate="2014-12-05T07:12:57.033" LastActivityDate="2014-12-05T07:12:57.033" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2095" PostTypeId="2" ParentId="1085" CreationDate="2014-06-09T10:15:54.553" Score="6" Body="&lt;p&gt;The boundaries to coastal models are frequently forced using information on water level (or, less commonly, velocities) predicted from databases of tidal constituents. These databases may be global or regional, and typically they offer a grid of points with constituents available at any of these points. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The products listed below are all produced by global tide models informed by satellite altimetry. All will give water levels, and some will also give depth-averaged velocities. As with any global tide model, caution should be exercised when applying them in coastal and/or shallow water regions, as they are unlikely to have the resolution (of bathymetry or computational mesh) to resolve coastal effects.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;OTIS&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;One source is the outputs of the Oregon State University Tidal Inversion Software (OTIS). OSU host a number of different data sets which are accessible from &lt;a href=&quot;http://volkov.oce.orst.edu/tides/&quot; rel=&quot;nofollow&quot;&gt;this page&lt;/a&gt;, along with the software required to extract constituents in FORTRAN or MATLAB. Both global and regional grids are available. The data here are based on TOPEX/POSEIDON satellite altimetry, combined through data assimilation techniques with a basic global tidal model and, in some cases, coastal tide gauges. The various grids have varying resolutions and varying numbers of tidal constituents.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;DTU10&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Another source is the &lt;a href=&quot;http://www.space.dtu.dk/English/Research/Scientific_data_and_models/Global_Ocean_Tide_Model.aspx&quot; rel=&quot;nofollow&quot;&gt;DTU10 model&lt;/a&gt; from the Technical University of Denmark. This information is produced from a global tidal model combined with TOPEX/POSEIDON data and also Jason-1 and Jason-2 satellite altimetry. The model is described in a poster &lt;a href=&quot;http://www.space.dtu.dk/english/~/media/Institutter/Space/English/scientific_data_and_models/global_ocean_tide_model/yongcuncheng_no_sv_1_68_45.ashx&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;. This model has a resolution of ${\frac{1}{8}}^{\circ}$ and includes twelve tidal constituents. Use of it is likely to be widespread in industry because it is included in the commercial modelling package &lt;a href=&quot;http://www.mikebydhi.com/&quot; rel=&quot;nofollow&quot;&gt;MIKE by DHI&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;FES2012&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The newest dataset listed here is &lt;a href=&quot;http://www.aviso.oceanobs.com/en/data/products/auxiliary-products/global-tide-fes.html&quot; rel=&quot;nofollow&quot;&gt;FES2012&lt;/a&gt;. More satellite data was used in its building than the other two models listed, and an improved model was used. The authors claim especially good performance in coastal and shelf regions.&#xA;Data are available on a ${\frac{1}{16}}^{\circ}$ grid with 32 tidal constituents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NB: this description is based on the linked web page. I have not personally used this dataset yet.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Regional databases&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;In order to minimize the effect of applying a global tide model solution to coastal and/or shallow water regions, regional tidal databases are available. Some examples are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;As mentioned above, &lt;a href=&quot;http://volkov.oce.orst.edu/tides/&quot; rel=&quot;nofollow&quot;&gt;OTIS&lt;/a&gt; provides a number of regional databases around the world with varying resolution (from 1/12 to 1/60 degrees).&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://adcirc.org/products/adcirc-tidal-databases/&quot; rel=&quot;nofollow&quot;&gt;ADCIRC&lt;/a&gt; tidal databases: One encompasses the Western North Atlantic, Caribbean and Gulf of Mexico (up to 60W); and another one the Eastern Pacific (from Alaska to Mexico).&lt;/li&gt;&#xA;&lt;li&gt;Many examples of local tidal model simulations are available for many specific locations, but the solutions are rarely available online.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h2&gt;Other sources of boundary data&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;All of the above data sources provide surface elevations from models. In the near future it may become feasible to produce velocity boundary conditions from &lt;a href=&quot;http://www.thebrahanproject.com/&quot; rel=&quot;nofollow&quot;&gt;land-based radar measurements&lt;/a&gt; of surface velocities in some areas.&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="111" LastEditDate="2014-06-10T00:52:23.177" LastActivityDate="2014-06-10T00:52:23.177" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2096" PostTypeId="1" CreationDate="2014-06-09T14:08:54.543" Score="15" ViewCount="2230" Body="&lt;p&gt;First of all, I am not expert at this so correct me. My hometown is Shiraz and since last year I can sense the earth is moving. I call them  mini earthquakes. But many people around me can not sense it. Some time ago there was an earthquake it felt like a 5 or even 6 richter earthquake but it was a 4 ricther earthquake but then in news they said that the depth was so close to the surface (4 km). I take a look at the USGS archives for Shiraz with in a 90 km diameter (as back in time as it was available) which I think will cover the major and minor fault lines. If you want to take a look its at &lt;a href=&quot;http://bit.ly/usgsarchive&quot; rel=&quot;noreferrer&quot;&gt;a link&lt;/a&gt;! usgs archives[a]&#xA;. And here is a diagram I made in excel.&#xA;&lt;img src=&quot;https://i.stack.imgur.com/rBduV.jpg&quot; alt=&quot;as&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is depth diagram (horizontal axis is the time and starts from 1974). What is interesting for me is that the depth of the earthquakes broke the boundary of 10km and stayed there for a much longer than it used to.And here is the magnitude diagram &#xA;&lt;img src=&quot;https://i.stack.imgur.com/bEKC2.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the map of major fault lines of Iran:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/SRNAX.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the same map (only the reverse fault lines):&#xA;&lt;img src=&quot;https://i.stack.imgur.com/L0GmS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And again the same map (only the lateral fault lines):&#xA;&lt;img src=&quot;https://i.stack.imgur.com/R8v49.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this a sign of fault lines building pressure? And why the depth of earthquakes are getting near the surface? Can a geologist make any kind of guess based on the pattern or this is not a pattern at all?&lt;/p&gt;&#xA;" OwnerUserId="566" LastEditorUserId="124" LastEditDate="2014-06-09T17:42:40.260" LastActivityDate="2016-05-21T19:48:29.550" Title="What does it mean when the depth of earthquakes get near the surface over a period of time?" Tags="|geophysics|earthquakes|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2097" PostTypeId="2" ParentId="1089" CreationDate="2014-06-09T14:21:14.003" Score="9" Body="&lt;p&gt;The link between orbital parameters and CO&lt;sub&gt;2&lt;/sub&gt; levels is, as you wrote, the temperature. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Orbital parameters may change, via feedback mechanisms, the atmospheric temperature. To my knowledge the most important feedback mechanism with respect to the Milankovich cycles is the ice-albedo feedback. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The temperature, however, is an important player in geochemical feedbacks which influence the concentration of gases like CO&lt;sub&gt;2&lt;/sub&gt; or methane. For CO&lt;sub&gt;2&lt;/sub&gt;, again to my knowledge, you named the most important feedback; the exchange of CO&lt;sub&gt;2&lt;/sub&gt; between atmosphere and ocean. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The exchange of CO&lt;sub&gt;2&lt;/sub&gt; between ocean and atmosphere in turn depends on the partial pressure of CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere and the surface layer of the ocean; there is uptake, release according to the pressure gradient.&#xA;Now, the partial pressure of CO&lt;sub&gt;2&lt;/sub&gt; in the surface layer depends also on the amount of carbon transported or received from the deep sea layers. There is way more CO&lt;sub&gt;2&lt;/sub&gt; stored in the cold water of the deep sea. So the exchange of CO&lt;sub&gt;2&lt;/sub&gt; does depend on the vertical circulation pattern of the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are, to my knowledge, three major mechanisms that transport carbon between the surface and the deep sea and they all depend on temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Solubility pump:&lt;/strong&gt; Cold water can store more CO&lt;sub&gt;2&lt;/sub&gt; than warm water. Therefore at the poles, where cold water is sinking into the deep sea, you have CO&lt;sub&gt;2&lt;/sub&gt; rich water. The CO&lt;sub&gt;2&lt;/sub&gt; stored in the deep sea can, as far as I know, remain there for hundreds of years, before it comes up again in the warmer upwelling regions at the equator. The temperature dependence of that mechanism is obvious.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Biological pump&lt;/strong&gt;: In the surface layer you have photosynthesis of algeas etc., so carbon is withdrawn from the layer and stored in biomass. A portion of dead plants is not reused (eaten) but sinks into the deep sea. The process is temperature dependend since biological activity depends on temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Carbonate pump&lt;/strong&gt;: The amount of carbonate and CO&lt;sub&gt;2&lt;/sub&gt; are linked to each other via marine chemistry. Animals building shells etc. need carbonate thereby also influencing the amount of CO&lt;sub&gt;2&lt;/sub&gt; present in the water. Again, a portion of this carbonate is withdrawn from the short term cycles once the animals die and sink to the deep sea. Again this mechanism is temperature dependend since biological activity is.&lt;/p&gt;&#xA;" OwnerUserId="526" LastEditorUserId="725" LastEditDate="2014-12-05T07:16:20.583" LastActivityDate="2014-12-05T07:16:20.583" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2099" PostTypeId="2" ParentId="2096" CreationDate="2014-06-09T14:40:07.363" Score="9" Body="&lt;p&gt;The data from USGS is somewhat misleading.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Determining earthquake depths is a difficult problem, particularly if you're using data recorded a long way from the earthquake. Event location methods often become unstable for very shallow earthquakes. With some methods/catalogues it is therefore normal to &quot;fix&quot; the depth of shallow earthquakes, and not attempt to find a more accurate depth. This is why you see so many earthquakes supposedly at 33km; I think the 10km ones may also be fixed. Really, this ought to be made more obvious in the USGS site (I think the information &lt;em&gt;is&lt;/em&gt; there if you dig deep enough!).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, it's impossible to draw any conclusions from these graphs: you're probably just seeing improvements in seismological techniques over time.&lt;/p&gt;&#xA;" OwnerUserId="427" LastActivityDate="2014-06-09T14:40:07.363" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2100" PostTypeId="1" AcceptedAnswerId="2101" CreationDate="2014-06-09T14:52:16.537" Score="11" ViewCount="5464" Body="&lt;p&gt;All the graphics I've seen showing epicenters with a hypocenter (labeled focus in the graph below) appear to show that epicenters are always directly above their related hypocenters. Is this correct?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ds6IC.gif&quot; alt=&quot;3D slice of Earth showing a Earthquake with the related fault, epicenter, and hypocenter&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="124" LastEditDate="2014-06-13T07:05:02.030" LastActivityDate="2019-05-09T10:26:55.333" Title="Is the epicenter always directly above the hypocenter?" Tags="|geophysics|earthquakes|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2101" PostTypeId="2" ParentId="2100" CreationDate="2014-06-09T15:04:53.587" Score="12" Body="&lt;p&gt;By definition, the answer is &lt;em&gt;yes&lt;/em&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;epicenter, the point on the earth's surface vertically above the focus of an earthquake, or the Hypocenter&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;according to &lt;a href=&quot;http://www.merriam-webster.com/dictionary/epicenter&quot; rel=&quot;nofollow noreferrer&quot;&gt;Merriam-Webster&lt;/a&gt; or a many other sources.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="-1" LastEditDate="2019-05-09T10:26:55.333" LastActivityDate="2019-05-09T10:26:55.333" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="2102" PostTypeId="1" AcceptedAnswerId="2103" CreationDate="2014-06-09T15:50:32.753" Score="7" ViewCount="193" Body="&lt;p&gt;Curious if to what degree it is possible to cluster epicentres as originating from a single formation/fault? Seems like it is possible that apart of the issue might being able to map the hypocentre of a faults slope, but what is not clear is if that is true, or if faults are really more a collections of formations that vary and at a high-level behave as one, but often independently behave when reviewed on a small scale due to the formations local attributes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which leads to my real question, what is a fault?&lt;/p&gt;&#xA;" OwnerUserId="284" LastEditorUserId="124" LastEditDate="2014-06-13T07:04:52.743" LastActivityDate="2014-06-13T07:04:52.743" Title="What is a fault?" Tags="|geophysics|earthquakes|tectonics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2103" PostTypeId="2" ParentId="2102" CreationDate="2014-06-09T18:44:08.443" Score="7" Body="&lt;p&gt;A fault is a crack in the rock that shows movement over time. The movement may have stopped (eg. small faults seen in the field in the UK) or be essentially dead even though the crack still represents a weakness that occasionally shows a small amount of movement (e.g. the Great Glen Fault in Scotland).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes it is often possible to map a fault in 3d by plotting the hypocentres in 3d. For example, a good estimate of the fault area that slipped can be found by plotting aftershocks of a large earthquake (although beware of adjoining faults that might see shocks as their stress regime has changed).&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2014-06-09T18:44:08.443" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2104" PostTypeId="2" ParentId="2100" CreationDate="2014-06-09T20:10:33.000" Score="5" Body="&lt;p&gt;Generally defined, an epicentre is just a projection of the hypocentre (aka focus), on the nearest outer surface of the body in which the seismic source occurs.&lt;/p&gt;&#xA;" OwnerUserId="571" LastActivityDate="2014-06-09T20:10:33.000" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2105" PostTypeId="1" AcceptedAnswerId="2112" CreationDate="2014-06-10T06:17:06.110" Score="11" ViewCount="272" Body="&lt;p&gt;For a project I am working on I received raw data from many meteorology stationes.&lt;br&gt;&#xA;Is it right practice to test this data against air temperature from noaa's &lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html&quot;&gt;ncep/ncar data&lt;/a&gt;?&lt;br&gt;&lt;/p&gt;&#xA;" OwnerUserId="83" LastActivityDate="2014-06-10T20:37:36.550" Title="Is it right practice to validate temperature data with reanalysis data?" Tags="|meteorology|temperature|database|validation|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2106" PostTypeId="1" AcceptedAnswerId="2109" CreationDate="2014-06-10T09:26:19.287" Score="11" ViewCount="16192" Body="&lt;p&gt;The title pretty much says it. I have the formula: $P = \rho g h$ where $\rho$ is the density, $h$ is how deep the pressure is in the Earth and $g$ is the gravitational acceleration(?).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't get the units either. If I substitute the units for each term I get this: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$P = \frac{\mathrm{kg}}{\mathrm{m}^3} \times \frac{\mathrm{m}}{\mathrm{s}^2} \times \mathrm{m} = \frac{\mathrm{kg}}{\mathrm{m}*\mathrm{s}^2}$$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shouldn't it be something like $P = \dfrac{\mathrm{kg}}{\mathrm{m}^2}$? As far as I'm concerned that's the unit for pressure. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where do I get this formula from and how do I derive the unit of measurement?&lt;/p&gt;&#xA;" OwnerUserId="521" LastEditorUserId="67" LastEditDate="2014-06-10T14:37:40.133" LastActivityDate="2017-02-01T06:42:51.453" Title="How do I derive the formula for lithostatic (overburden) pressure?" Tags="|geophysics|geology|geodynamics|" AnswerCount="2" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2107" PostTypeId="2" ParentId="1076" CreationDate="2014-06-10T12:44:17.343" Score="21" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;What's the minimum &amp;quot;uprightness&amp;quot; for it to not get obscured by snow and stay readable throughout the year?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The answer to this problem is not in the angle at all. No amount of math will give you an angle at which you can reasonably presume your surface will remain clear. Snow can (and does) accumulate on vertical and even negatively sloped surfaces. Instead of thinking about the angle, you should be thinking about the materials and conditions involved.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/eYWphm.jpg&quot; alt=&quot;Snow covered vertical signage&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;There are lots of factors that determine whether snow will stick, but a few that stand out most are:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Temperature differentials between a surface and the atmosphere:&lt;/p&gt;&#xA;&lt;p&gt;This is particularly noticeable on surfaces of enclosures such as vehicles or buildings where the internal temperature causes the surface to be out of sync with the environment. You might notice snow collecting on the vertical glass surface of car side windows. This will be more pronounced in cars that were parked full of warm air when it started snowing. The warm glass would have melted the initial snow flakes. The wet surface will eventually freeze giving  a textured surface for new snow flakes to sit on instead of sliding off.&lt;/p&gt;&#xA;&lt;p&gt;The same is true for objects with thermal mass that retain heat or cold after a sudden change in air temperature.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Surface properties such as roughness.&lt;/p&gt;&#xA;&lt;p&gt;If even a few snow flakes find purchase on a surface, more will  find a way to build on that and obscure your surface. This is far more important than angle.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Atmospheric conditions such as humidity and the nature of the snow flakes formed.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;To effectively keep a surface clear it should be ① smooth, ② quickly transfer heat to adapt to the current air temperature, and ③ be sheltered from being in contact with falling snow in the first place. Even highway signs with are smooth, vertical and thin metal are only so effective  at staying clear and in some regions will have eaves protecting them from some snowfall.&lt;/p&gt;&#xA;" OwnerUserId="576" LastEditorUserId="6298" LastEditDate="2021-12-08T07:20:13.767" LastActivityDate="2021-12-08T07:20:13.767" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="2108" PostTypeId="2" ParentId="2106" CreationDate="2014-06-10T13:32:13.537" Score="5" Body="&lt;p&gt;The SI unit for force is the &lt;em&gt;Newton&lt;/em&gt;, not the kilogram. This is defined from Newton's Second Law: $F = ma$. Hence, dimensionally, force (Newton) is  1 kg·m·s&lt;sup&gt;-2&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pressure is force per distance squared (kg·m·s&lt;sup&gt;-2&lt;/sup&gt; / m&lt;sup&gt;2&lt;/sup&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hence, dimensionally, pressure is kg / m·s&lt;sup&gt;2&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the formula, the pressure is due to the force (weight) of all the overlying rock. $F=ma$ again. Except we're talking about pressure (ie. force per unit area), so we consider this &quot;per unit area&quot; in the formula. i.e.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;P = \left(\begin{array}\text{\text{mass of column of 1 m}}^2\\\text{ of rock up to the surface}\end{array}\right) \times \text{acceleration due to gravity} \\&#xA;P = (\text{depth} \times \rho) \times g&#xA;$$&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorUserId="67" LastEditDate="2014-06-10T15:35:25.363" LastActivityDate="2014-06-10T15:35:25.363" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2109" PostTypeId="2" ParentId="2106" CreationDate="2014-06-10T13:39:43.080" Score="14" Body="&lt;p&gt;This isn't that difficult, but anything is if you start from the wrong place. Let's derive this thing:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$P = \frac{F}{A}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where $P$ is pressure, and $A$ is the area the force is pushing down on. Let's take a break and derive the units first, just so we know our end derivation is correct; $F$ is in Newtons, which comes out to $\mathrm{kg} \times \frac{\mathrm{m}}{\mathrm{s}^2}$ and $A$ is in $\mathrm{m}^2$. This means that pressure is $\frac{\mathrm{kg}}{\mathrm{m}\times\mathrm{s}^2}$. So your first substitution is correct. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now that that is established, let's think about lithostatic pressure, and break up the original equation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$P = \frac{M \times a}{A} $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We know that $a = g$, gravitational acceleration, but what we really want is to figure out how to get this equation in terms of density, so &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\rho = \frac{M}{V}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\rho$ is density, $M$ is mass, and $V$ is volume. If we substitute this equation in for mass in the pressure equation, we get &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$P = \frac{\rho V \times g}{A}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;let's now separate $V$ and $A$, $$V = \ell \times w \times h$$ $$A = \ell \times w$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So canceling out $\ell$ and $w$, our final equation shows&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$P = \rho gh$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;or lithostatic pressure.&lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="67" LastEditDate="2014-06-10T14:47:09.483" LastActivityDate="2014-06-10T14:47:09.483" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2110" PostTypeId="2" ParentId="2105" CreationDate="2014-06-10T15:54:25.830" Score="8" Body="&lt;p&gt;Many meteorological stations are assimilated into NOAA's reanalysis. You should be careful with this approach as the raw data you have might have been already included in the hindcast.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reanalysis includes the data in an statistical way. In general, the reanalysis does not match the data at any point, but tries to minimize the global difference between observations and model simulation. There is no guarantee that the reanalysis is going to be close to any of the assimilated data.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2014-06-10T20:37:36.550" LastActivityDate="2014-06-10T20:37:36.550" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2111" PostTypeId="2" ParentId="2105" CreationDate="2014-06-10T16:55:14.393" Score="3" Body="&lt;p&gt;Official meteorological stations should have well-calibrated thermometers.&#xA;In any comparison between models and measurements, the measurements would be the reference, not the models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One way I can see to validate ground-based in-situ temperature measurements is by carrying an &lt;a href=&quot;http://www.l-a-b.com/content/measurement-traceability&quot; rel=&quot;nofollow&quot;&gt;SI-traceable&lt;/a&gt; thermometer to all the sites.&#xA;Unfortunately, you cannot do this retroactively.&#xA;I don't know to what degree thermometers at official meteorological stations are SI-traceable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another way would be to look at spatio-temporal series, and search for outliers that way.  This would not be a comparison between different independent methods, but would reject a particular measurement if it is too far off compared to measurements nearby in space and time.  To find the right criteria to reject data is a delicate balance, and you will certainly end up either rejecting good data or accepting bad data.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2014-06-10T18:04:39.707" LastActivityDate="2014-06-10T18:04:39.707" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2112" PostTypeId="2" ParentId="2105" CreationDate="2014-06-10T19:33:04.167" Score="9" Body="&lt;p&gt;No. One should not attempt to validate raw in situ measurements with reanalysis data. Reanalysis data contain partial information from observations, but are mostly model fields and are provided at very coarse resolution (~1$^\circ$ longitude). In situ measurements are subject to very local, small scale effects, and have different meaning from reanalysis. One is always free to compare the two datasets, but this would not be validation in any meaningful way.  &lt;/p&gt;&#xA;" OwnerUserId="192" LastActivityDate="2014-06-10T19:33:04.167" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2113" PostTypeId="1" CreationDate="2014-06-11T02:44:55.963" Score="15" ViewCount="23322" Body="&lt;p&gt;If it rains real hard, is there a chance the rain's duration will be shorter? I think the if the rain in the clouds disperses with such force the rain will be over faster than if it was just a light drizzle. Can anyone confirm/deny this? Is there a percentage or study shown on rain duration relative to the rain's strength?&lt;/p&gt;&#xA;" OwnerUserId="578" LastEditorUserId="10681" LastEditDate="2017-09-13T00:08:13.387" LastActivityDate="2017-09-13T00:08:13.387" Title="If it rains harder, does it mean the rain's duration will be shorter?" Tags="|meteorology|weather-forecasting|rainfall|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2114" PostTypeId="1" AcceptedAnswerId="4263" CreationDate="2014-06-11T17:20:59.757" Score="7" ViewCount="1182" Body="&lt;p&gt;How are specific discharge and flux linked?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is flux simply &lt;code&gt;specific discharge × area&lt;/code&gt;? And when we speak of flux of an element eg. N-flux, is that &lt;code&gt;specific discharge × concentration × area&lt;/code&gt;?&lt;/p&gt;&#xA;" OwnerUserId="580" LastEditorUserId="725" LastEditDate="2014-12-06T23:14:34.857" LastActivityDate="2015-01-14T05:17:31.313" Title="The relationship between specific discharge and flux" Tags="|hydrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2115" PostTypeId="2" ParentId="2113" CreationDate="2014-06-11T18:10:55.097" Score="15" Body="&lt;p&gt;The intensity of a rainstorm does not actually &lt;strong&gt;cause&lt;/strong&gt; the duration of the precipitation to be shorter. There is a strong &lt;em&gt;correlation&lt;/em&gt;, but not in the sense you may be implying here (let me get back to that in moment).&lt;/p&gt;&#xA;&lt;p&gt;First you have to dispel the model that a cloud is a big container of water, and if it &amp;quot;rains harder&amp;quot;, the cloud will run out of water quicker and the rain event will be shorter in duration. Rain doesn't really work like that.&lt;/p&gt;&#xA;&lt;p&gt;The atmosphere everywhere (even outside the cloud) contains lots and lots and lots of water. And under a stable combination of temperature, pressure, and humidity, all that moisture is perfectly happy to exist in a completely gaseous state. But as differing air masses (different temperatures, pressure, and humidity) start to collide, the local atmospheric conditions can fall outside the range where water can exist in a completely gaseous state. That is known as the &lt;a href=&quot;http://en.wikipedia.org/wiki/Dew_point&quot; rel=&quot;noreferrer&quot;&gt;dew point&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;A &lt;em&gt;cloud&lt;/em&gt; is where two differing atmospheric conditions have met, and the resulting condensed water droplets simply do not have sufficient weight to overcome the updraft speed of the air around it. If the air masses mix slowly, the rate of condensation will occur slowly and over a longer period of time. The resulting clouds may simply &amp;quot;evaporate&amp;quot; as the local conditions stabilize, or the condensing water may slowly precipitate over the ground (gentle rain), or the precipitation may never reach the ground at all (&lt;a href=&quot;http://www.weatherquestions.com/What_causes_precipitation.htm&quot; rel=&quot;noreferrer&quot;&gt;virga&lt;/a&gt;). These gentler atmospheric changes tend to play out over longer periods of time because the air masses are moving more slowly so it takes longer for the differences to mix and settle down into a new steady state.&lt;/p&gt;&#xA;&lt;h3&gt;Here's the part where I talk about intensity&lt;/h3&gt;&#xA;&lt;p&gt;If two air masses have widely varying conditions (think warm moist air over the ocean meeting dryer hotter conditions over the land) and they meet more abruptly (higher wind speeds), this causes a more-violent disturbance; the moisture from the air will condense more quickly, the rain falls faster and harder, and the whole thing ends (relatively speaking) more quickly.&lt;/p&gt;&#xA;&lt;p&gt;But the duration tends to be shorter because the reaction between the differing masses is occurring at a faster rate — so the whole event will generally play out more quickly. But it is perfectly conceivable that &amp;quot;harder rain&amp;quot; can last much longer if the storm system continues to pull in more of the moist atmosphere around it. In extreme circumstances, that's pretty much what a hurricane is; the storm itself gets so big that it starts to create it's own &lt;em&gt;system&lt;/em&gt; that pulls in more and more atmosphere around it. The rain doesn't simply stop when all the rain has fallen out of the original clouds. It actually (continually) makes new clouds/precipitation as it continues to draw in the atmosphere surrounding it.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;But speaking in &lt;em&gt;broad&lt;/em&gt; generalities,&lt;/strong&gt; the faster the disturbance occurs, the faster the moisture will condense, the harder the precipitation will fall, the more quickly the conditions will stabilize, and the duration of the rain will be less.&lt;/p&gt;&#xA;" OwnerUserId="36" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-06-12T17:02:10.937" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2116" PostTypeId="2" ParentId="2113" CreationDate="2014-06-11T19:14:58.787" Score="8" Body="&lt;p&gt;Robert Cartanio's answer makes very good points, and I'll accentuate them with some examples.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thunderstorms tend to produce &quot;hard rain&quot; and larger scale organized convection will have areas of hard rain and areas of weaker rain.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Air-mass thunderstorms are the type of daily convection you see in Florida and elsewhere.  These tend to appear somewhat fast, rain out and be gone in short time.  The other answer dispels the idea that the clouds rain themselves away.  The reason for the short duration is that the rain cooled air underneath the storm blocks new moist warm air from entering the storm cloud, and it as the moisture is cut off, the storm dies.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A contrary example is a supercell thunderstorm, which will have extremely heavy precipitation and hail near the updraft.  These storms can persist for hours, but your perception of how long the &quot;heavy rain&quot; lasts will be a function of the storm motion.  A fast-moving supercell may pass by at 70 knots and you'll experience the heavy rain for a few minutes.  A stationary supercell will give you the impression that the heavy rain lasts for an hour or longer.   If you follow both of the storms they may have produced heavy rain for the same amount of time.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly, a squall line will produce heavy precip with lighter precipitation behind it (usually, the stratiform rain can precede the convective rain or be laterally offset from it).  How long this precip lasts (from your point of view) will depend on how fast it is moving.  Regardless of how long you observe it for, it will likely last much longer as it moves.  The stratiform region will be larger than the convective reason, so you will observe the lighter rain lasting longer than the heavy rain, but both will last for similar time scales.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the cold season it is not uncommon to find stratiform rain, drizzle or snow that seems to last all day, and this might give the impression that light rain lasts a long time.  In the hurricane season, strong convection can persist for weeks (though it might only observe a timescale of a day as it makes landfall where you live).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The point of all this is that the duration and intensity are strongly a function of the dynamics and your Eulerian point of view observing at a fixed location as a storm moves by.  In the Lagrangian sense you'll find the correlation between duration and  precipitation intensity is dependent on the dynamic and thermodynamic environment they are in.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-06-11T19:14:58.787" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2117" PostTypeId="2" ParentId="990" CreationDate="2014-06-12T07:53:05.533" Score="9" Body="&lt;p&gt;Since this percentage is an area ratio, it fluctuates with sea level. Consequently it has fluctuated quite a few during the Phanerozoic (see &lt;strong&gt;Haq et al. 1988; Miller et al. 2005&lt;/strong&gt; for instance).&lt;br&gt;&#xA;Now if we're talking in term of oceanic/continental crust ratio, the present day continental crust age repartition shows that, by 2 Ga, ca. 60% of the present day continental crust was already formed (see e. g. &lt;strong&gt;Hawkesworth &amp;amp; Kemp 2006&lt;/strong&gt;) meaning that most of the variation in oceanic/continental crust occurred prior to the middle Paleoproterozoic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Haq et al. 1988. Mesozoic and Cenozoic chronostratigraphy and cycles of sea-level changes. SEPM Special Publication, 42: 71-108.&lt;br&gt;&#xA;Hawkesworth &amp;amp; Kemp 2006. &lt;a href=&quot;http://dx.doi.org/10.1038/nature05191&quot;&gt;Evolution of the continental crust&lt;/a&gt;. Nature, 443: 811-817.&lt;br&gt;&#xA;Miller et al. 2005. &lt;a href=&quot;http://dx.doi.org/10.1126/science.1116412&quot;&gt;The Phanerozoic Record of Global Sea-Level Change&lt;/a&gt;. Science, 310: 1293-1298.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastActivityDate="2014-06-12T07:53:05.533" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2118" PostTypeId="5" CreationDate="2014-06-13T03:52:59.340" Score="0" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Plate_tectonics&quot; rel=&quot;nofollow noreferrer&quot;&gt;Plate tectonics&lt;/a&gt; describes the large-scale motion of the large plates composing Earth's lithosphere. The model builds on the concept of continental drift.&lt;/p&gt;&#xA;" OwnerUserId="-1" LastEditorUserId="11908" LastEditDate="2019-02-03T19:34:19.407" LastActivityDate="2019-02-03T19:34:19.407" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="2119" PostTypeId="4" CreationDate="2014-06-13T03:52:59.340" Score="0" Body="The theory that Earth's outer shell is divided into several plates that glide over the mantle, the rocky inner layer above the core." OwnerDisplayName="user2872" LastEditorDisplayName="user2872" LastEditDate="2015-05-06T21:46:00.263" LastActivityDate="2015-05-06T21:46:00.263" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2120" PostTypeId="1" AcceptedAnswerId="2121" CreationDate="2014-06-13T04:09:15.547" Score="6" ViewCount="757" Body="&lt;p&gt;The Ring of Fire goes through the places that have the most earthquakes. Why is the Ring of Fire there, not somewhere else?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/M6V83.jpg&quot; alt=&quot;ring of fire&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any help would be appreciated!&lt;/p&gt;&#xA;" OwnerUserId="584" LastEditorUserId="124" LastEditDate="2014-06-13T07:04:58.267" LastActivityDate="2014-06-13T14:32:15.813" Title="Why is the Ring of Fire there?" Tags="|geophysics|earthquakes|plate-tectonics|geography|" AnswerCount="1" CommentCount="2" ClosedDate="2014-06-18T22:43:31.037" ContentLicense="CC BY-SA 3.0" />
  <row Id="2121" PostTypeId="2" ParentId="2120" CreationDate="2014-06-13T14:32:15.813" Score="8" Body="&lt;p&gt;This question is very similar to: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/173/why-does-the-ring-of-fire-pretty-much-define-pacific-rim/&quot;&gt;Why does the &amp;quot;Ring of Fire&amp;quot; pretty much define &amp;quot;Pacific Rim&amp;quot;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The high levels of volcanoes and earthquakes are primarily due to subduction. So why is the Pacific surrounded by subduction zones?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Think back to Pangaea. This was a supercontinent that formed in the late Palaeozoic. Virtually all of the Earth's land masses were concentrated in one large supercontinent. When this broke up, the new continents moved away from each other. Fast forward 200Ma or so, and you find that the continents have moved so far apart that they are now converging on a point on the other side of the planet - the continents are moving towards each other! Hence the remains of the super ocean (which was actually multiple ocean plates - today's Pacific &amp;amp; Nazca plates, plus the Farrallon plate (RIP),etc ) is shrinking as the continental plates move towards it. This destruction of the ocean plate(s) occurs at subduction zones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a big picture generalisation. Not all of the Pacific's boundaries are marked with subduction zones (e.g. North America has two large strike slip systems + a new spreading ridge). Also, not all of the continents are converging on each other. Africa is doing a pirouette, India is moving northwards, etc.&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-06-13T14:32:15.813" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2122" PostTypeId="1" AcceptedAnswerId="2493" CreationDate="2014-06-15T04:16:18.847" Score="13" ViewCount="2286" Body="&lt;p&gt;I'm curious about how mountains on an airless world such as the Moon would look if you were standing on the surface and looking at them. There are plenty of artists' impressions, of course, but I'm curious about whether there are any existing photographs of such a scene.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From browsing photographs of the Moon landings, there are a few surprisingly rounded-looking low hills on the horizon, but not what you'd call an actual mountain. This makes sense, since the missions targeted large flat areas where it would be safe to land. There are photographs of mountains seen from Lunar orbit, but not from the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are photographs of Mount Sharp from the Curiosity mission to Mars, but Mars has an atmosphere, and to my untrained eye Mount Sharp looks quite eroded.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I'm wondering whether there are any such photos in existence at all - either because a probe has landed on an airless body close enough to a mountain to get a picture, or because a camera in orbit has been aimed at the horizon in order to capture a mountain range from the same angle at which it would be seen from the surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alternatively, are there any mountains on Earth where (for whatever reason) erosion hasn't played a big role in shaping them so far, and which therefore look similar to the uneroded mountains one would find on an airless world?&lt;/p&gt;&#xA;" OwnerUserId="215" LastActivityDate="2022-12-27T12:41:59.713" Title="Are there any photographs of mountains without significant erosion (on Earth or otherwise)" Tags="|planetary-science|mountains|erosion|" AnswerCount="6" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2123" PostTypeId="2" ParentId="2122" CreationDate="2014-06-15T09:47:44.657" Score="18" Body="&lt;p&gt;Here's how astronomers of the late 19th century thought the Moon would appear:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/2/22/Old_view_moon.jpg/403px-Old_view_moon.jpg&quot; alt=&quot;&quot; /&gt;&lt;br /&gt;&#xA;&lt;em&gt;Recreations in Astronomy&lt;/em&gt; by H. D. Warren D. D., published in 1879, via &lt;a href=&quot;http://en.wikipedia.org/wiki/Selenography&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://en.wikipedia.org/wiki/Selenography&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Here's what Apollo 15 astronauts saw:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hwBZV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hwBZV.jpg&quot; alt=&quot;&quot; /&gt;&lt;/a&gt;&lt;br/&gt;&lt;sub&gt;(source: &lt;a href=&quot;https://www.jpl.nasa.gov/images/alhat/Apoll15_Comp20081223-640.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;nasa.gov&lt;/a&gt;)&lt;/sub&gt;&lt;br/&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Apollo 15 Lunar Module Falcon at the Hadley-Apennine landing site. Hadley Delta in the background rises approximately 4,000 meters (about 13,124 feet) above the plain. The base of the mountain is approximately 5 kilometers (about 3 statute miles) away.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Source: NASA, from &lt;a href=&quot;https://web.archive.org/web/20210506215233/https://www.jpl.nasa.gov/news/news.php?feature=1990&quot; rel=&quot;nofollow noreferrer&quot;&gt;Four Out of Six Apollos&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Below is a photograph of the even taller Mons Hadley, 1.1 km taller than Hadley Delta shown above:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/X4hBc.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/X4hBc.jpg&quot; alt=&quot;&quot; /&gt;&lt;/a&gt;&#xA;Source: NASA, photograph as15-86-11603, from &lt;a href=&quot;https://web.archive.org/web/20181229014130/https://spaceflight.nasa.gov/gallery/images/apollo/apollo15/html/as15-86-11603.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Apollo Imagery&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Compare the above with mountains on the Earth. Here's a picture of Mont Blanc, a mountain here on the Earth comparable in size to  the smaller of the two lunar mountains portrayed above:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/0/0e/Mont_Blanc_Panorama_from_Mont_Blanc_Refugee,_Italy.jpg/640px-Mont_Blanc_Panorama_from_Mont_Blanc_Refugee,_Italy.jpg&quot; alt=&quot;&quot; /&gt;&#xA;Photograph by Zoharby, taken from &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Mont_Blanc_Panorama_from_Mont_Blanc_Refugee,_Italy.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikimedia Commons&lt;/a&gt;, licensed under &lt;a href=&quot;https://creativecommons.org/licenses/by-sa/3.0/deed.en&quot; rel=&quot;nofollow noreferrer&quot;&gt;Creative Commons Attribution-ShareAlike 3.0 Unported&lt;/a&gt; license.&lt;/p&gt;&#xA;&lt;br&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Alternatively, are there any mountains on Earth where (for whatever reason) erosion hasn't played a big role in shaping them so far, and which therefore look similar to the uneroded mountains one would find on an airless world?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Nathaniel, you have a mistaken view of erosion. Erosion eventually does tear the tallest mountains down to tiny little hills. However, erosion also makes those tall mountains very jagged at first. Erosion is the primary reason why Mont Blanc and other new, tall mountains are so jagged. Liquid water seeps into cracks in the rocks and then freezes into ice. Ice has a lower density than water. This means that liquid water expands upon freezing. That expansion breaks the rock that form mountains into jagged edges.&lt;/p&gt;&#xA;&lt;p&gt;Another reason our mountains are jagged is plate tectonics. The Earth is the only body in the solar system that exhibits plate tectonics. New continental crust forms largely from older continental crust. Erosion eventually brings particles torn from mountains to a flat area or river delta, where they collect. The material brought to those collection areas changes over time. The end result: Strata (layered rock formations). The different strata in rock have different strengths and weaknesses and thus erode differently. That differential erosion results in jagged mountains.&lt;/p&gt;&#xA;&lt;br&gt;&#xA;Bottom line: You don't see jagged mountains on the Moon or Mars because they don't have water in all three phases and because they don't have plate tectonics.&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2022-12-27T12:41:59.713" LastActivityDate="2022-12-27T12:41:59.713" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="2124" PostTypeId="1" CreationDate="2014-06-15T10:18:36.453" Score="1" ViewCount="104" Body="&lt;p&gt;Is it true, that circumpolar regions around North pole, were not submerged in water and had a habitable genial climate, until  the last Iceage, or glacial period?&lt;/p&gt;&#xA;" OwnerUserId="586" LastActivityDate="2014-08-17T15:32:38.210" Title="Circum polar regions in Interglacial periods" Tags="|ice-age|poles|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2125" PostTypeId="1" CreationDate="2014-06-15T11:38:15.707" Score="10" ViewCount="100" Body="&lt;p&gt;The idea is to design an integrated marine monitoring network by surveying in parallel the chlorophyll-a and the other oceanography parameters, which are either trophically related with the concentration of chlorophyll-a (e.g. nutrients, zooplankton) or topically-related (having the same origin), e.g. nutrients and contaminants have the same land-based point sources of pollution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The simplest approach is to place the sampling stations at equal distance from the land-based sources of pollution to detect of the pressure from pollution with nutrients and contaminants and its effect on the marine ecosystem. This approach is supported by the fact that the water column parameters have relatively homogeneous distribution, because of the water mixing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question is: is there an argument for applying a more sophisticated approach of using the analysis average multi-annual satellite-derived spatial change in the concentration of chlorophyll-a for choosing a sampling location of the monitoring network? And if it is, what method can be used to place the sampling stations (Besides the &lt;a href=&quot;http://resources.arcgis.com/en/helmain/10.1/index.html#//00300000000p000000%29&quot; rel=&quot;nofollow noreferrer&quot;&gt;ArcGIS Sampling Network Design Tool&lt;/a&gt;)?&lt;/p&gt;&#xA;" OwnerUserId="588" LastEditorDisplayName="user20559" LastEditDate="2021-09-25T03:03:48.330" LastActivityDate="2021-09-25T03:03:48.330" Title="Argument for designing an ocean monitoring network based on satellite-derived chlorophyll-a concentration?" Tags="|oceanography|satellites|in-situ-measurements|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2126" PostTypeId="1" AcceptedAnswerId="2142" CreationDate="2014-06-15T14:12:26.277" Score="8" ViewCount="556" Body="&lt;p&gt;In mountainous areas there is often little or no air pollution such as particulate matter, sulphur/nitrogen dioxide etc. However, ground-level ozone is frequently &lt;em&gt;more&lt;/em&gt; present at these higher altitudes. For example, in the Pyrenees mountains between France and Spain there is little or no pollution however they show high ozone readings. The Alps show the same situation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reference maps:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.eea.europa.eu/themes/air/interactive#b_start=0&quot;&gt;http://www.eea.europa.eu/themes/air/interactive#b_start=0&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.eea.europa.eu/themes/air/air-quality/map/airbase/air-quality-statistics-at-reporting-stations#content-core&quot;&gt;http://www.eea.europa.eu/themes/air/air-quality/map/airbase/air-quality-statistics-at-reporting-stations#content-core&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="589" LastActivityDate="2014-11-25T15:35:25.577" Title="Is ground level ozone dangerous to human health when other pollutants are not present, for example, at high altitudes?" Tags="|ozone|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2127" PostTypeId="1" CreationDate="2014-06-15T17:49:34.600" Score="15" ViewCount="167" Body="&lt;p&gt;&lt;a href=&quot;http://web.stanford.edu/~bakerjw/GMPEs.html&quot;&gt;Ground motion prediction equations&lt;/a&gt; (GMPEs) estimate ground motion at any given site due to an earthquake at a distance. There are many such equations, each with different parameters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can somebody please suggest those equations which can estimate peak ground acceleration (PGA) values from a 3-D rupture from parameters like rupture distance, Joyner–Boore distance, and so on?  &lt;/p&gt;&#xA;" OwnerUserId="590" LastEditorUserId="28050" LastEditDate="2015-04-16T18:18:26.927" LastActivityDate="2015-04-16T18:18:26.927" Title="What are the ground motion prediction equations for 3-D ruptures?" Tags="|geophysics|seismology|earthquakes|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2128" PostTypeId="1" AcceptedAnswerId="2129" CreationDate="2014-06-15T18:02:30.020" Score="9" ViewCount="700" Body="&lt;p&gt;How is the thickness/depth of ice sheets from previous glaciation periods determined? I've for instance often seen statements that the ice sheet over Scandinavia at the last glacial period maximum (i.e. &lt;a href=&quot;http://en.wikipedia.org/wiki/Last_glacial_period#&quot;&gt;Weichel&lt;/a&gt;) was 3-4 km thick, but haven't seen how this is calculated. Is this determined only by the rate of subsequent &lt;a href=&quot;http://en.wikipedia.org/wiki/Post-glacial_rebound&quot;&gt;post-glacial rebound&lt;/a&gt;, basically the inferred weight of the ice sheet, or is it based on other information as well (e.g. historical sea levels as an estimate of the amount of water tied up in ice sheets)?&lt;/p&gt;&#xA;" OwnerUserId="505" LastEditorUserId="11908" LastEditDate="2019-03-16T18:05:25.933" LastActivityDate="2019-03-16T18:05:25.933" Title="How are the thickness of ice sheets from previous glaciation periods determined?" Tags="|glaciology|ice-sheets|glaciation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2129" PostTypeId="2" ParentId="2128" CreationDate="2014-06-15T18:21:39.470" Score="6" Body="&lt;p&gt;There is no direct way to determine past ice thickness. The only solid information that exists are past areal extent. But, even this information is not necessarily clear since later advances may have overridden the past terminal positions and dating may not be exact. A main issue is the synchronicity of all such positions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With a past extent it is possible to calibrate numerical ice sheet models, based on our understanding of ice physics and dynamics and generate likely ice sheet configurations. Such models generate a three-dimensional ice sheet which includes ice thickness. In essence this is the best possible scenario for estimating such past ice thicknesses. Advanced models also include some form of isostacy depending on the overlying ice load. For the last Glacial Maximum, the rebound values are also used to constrain the ice sheet geometry. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem is, however, that the response of the Earth's crust to loading depends on the loading history and it would be possible to accomplish similar results with different scenarios since the depression of the crust is in part the loading but also the time scale of the loading. For a long time we though the latest glaciation was one long period of glaciation but we now know that, at least the Fennoscandian ice sheet, experienced two major advances, the mid-Weichselian and the Last Glacial maximum and both were relatively short in duration. This allows us to modify the loading history of the latest glacation. With the earlier glaciations, we do not yet have such detailed loading histories and are thus not able to make detailed models of ice thickness.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It should be added the the understanding of the variations of the last ice sheet come from a series of indirect sources such as sea-level changes, paleo-climate records e.g., (ice cores) and interstadial paleoclimate reconstructions. This means that as our understanding of these indirect records are improved, we can also improve our ice sheet forcing. Add to that uncertainties about basal conditions beneath past ice sheets that affect their dynamics and it is easy to see that past ice thickness values are uncertain. We can, however, obtain reasonable estimates from the models which could be accurate to within, perhaps 500 m (my guestimate).&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2014-06-15T18:21:39.470" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2130" PostTypeId="1" CreationDate="2014-06-16T04:49:27.913" Score="13" ViewCount="7113" Body="&lt;p&gt;While passing through layers inside the earth some P waves get converted to S waves and then back to P waves while returning towards the surface. Is this statement true? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If yes, then why? (Considering that they are both fundamentally different in terms of wave theory - longitudinal vs. transverse)&lt;/p&gt;&#xA;" OwnerUserId="593" LastEditorUserId="67" LastEditDate="2014-06-16T07:14:20.310" LastActivityDate="2014-06-16T10:22:04.107" Title="P wave to S wave conversion" Tags="|geophysics|seismology|waves|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2131" PostTypeId="1" CreationDate="2014-06-16T09:06:33.610" Score="10" ViewCount="139" Body="&lt;p&gt;I recently read a pop-science article about sea-water infilitration into (sweet) groundwater. One specific instance mentioned was the gaza strip: Exzessive well building and drawing of groundwater lowers the groundwater level, this leads to sea water infiltration. Then the article states the the nitrate content in the groundwater is higher, leading to &lt;a href=&quot;http://en.wikipedia.org/wiki/Blue_baby_syndrome#Other_causes&quot;&gt;blue baby sysndrome&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, I assume that an elevated nitrate content in the groundwater is due to fertilizer runoff, damaged sewer systems or similiar and unrelated to the saltwater problem, the author of the article simply mixed those problems up. But I'm not sure, hence this question: &lt;strong&gt;Is there any causal link between sea-water inflitration and groundwater nitrate?&lt;/strong&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;An answer not specific to Gaza would be ok as I want to understand possible mechanisms.&lt;/p&gt;&#xA;" OwnerUserId="117" LastActivityDate="2014-08-19T02:40:11.363" Title="Is there any link between sea-water inflitration into groundwater and nitrate?" Tags="|hydrology|sea-level|groundwater|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2132" PostTypeId="2" ParentId="2130" CreationDate="2014-06-16T10:22:04.107" Score="16" Body="&lt;p&gt;P and S waves are fundamentally different, when it comes to properties of the wave. An example might be that &lt;a href=&quot;http://en.wikipedia.org/wiki/P-wave&quot;&gt;P waves&lt;/a&gt; can travel through fluids while S waves cannot. However, when it comes down to wave theory, these two are just different polarizations of a &lt;a href=&quot;http://en.wikipedia.org/wiki/Mechanical_wave&quot;&gt;mechanical wave&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Seismology&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;In seismics this concept may be puzzling as we make some very fundamental assumptions. However, seismologists are very well aware that these polarizations (they call them &lt;em&gt;phases&lt;/em&gt;) usually change throughout their travelpath. When you look at the image below, you can see different travelpaths and the same source will trigger P and S waves. This P wave will travel to the point P where it can be recorded as direct P wave. Upon reflection it will be partially converted to a S wave, which you can also see on the nomination PP is the P part of the reflected P wave and PS is the S part of the reflected and converted P wave. (Actually you can go on happily converting back and forth.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/G5D4p.jpg&quot; alt=&quot;Travelpaths of waves after EQ&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Seismics&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;In seismics we get this conversion on interfaces or layer boundaries (whichever name you use). So everytime a wave is reflected it may also be partially converted into a different polarization. So essentially, your statement is wrong. The wave doesn't just convert passing through a layer, it is converted upon interaction with an interface. &#xA;So while this wasn't a yes directly to your question let me elaborate why this conversion happens.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/wBlkT.gif&quot; alt=&quot;Reflectivity of PP and PS conversions at an interface - Source: Crewes.org&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This picture basically shows the rate of conversion depending on the incident angle. At 30° the rate of conversion is maximized. (The scales are terrible to read sorry.) At this interface we can see the incident wave as excitor of a new wave package. So we have to take a detour into wave excitation.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Exctiting waves&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;In marine seismics we can excite pure P waves, because we're operating in a fluid. On land you will always excite a mix of P and S waves (and variations thereupon, namely surface waves). The excitation of these waves is direction dependent. Starting a P wave in one direction will always start an S wave component perpendicular to this direction. Of course we have some energy distribution so that we get something like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/9n4il.png&quot; alt=&quot;Daghero, Dario, et al. &amp;quot;Strong-coupling d-wave superconductivity in PuCoGa5 probed by point-contact spectroscopy.&amp;quot; Nature communications 3 (2012): 786.&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;P waves in the &lt;strong&gt;+&lt;/strong&gt; direction and S waves in the &lt;strong&gt;-&lt;/strong&gt; direction. (This image was vor conductivity but it serves the point.)&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;At the interface&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;We have to look at the incident wave as an excitor at the interface, which will give us a P and a S wave response. In seismics, &lt;a href=&quot;http://en.wikipedia.org/wiki/Focal_mechanism&quot;&gt;wave theory&lt;/a&gt; and other solutions you can usually see the S wave solution stands perpendicular on a P wave solution (except when we're dealing with anisotropy). So yes in the end your incident wave will start two P waves and two S waves that look like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Irhxt.gif&quot; alt=&quot;Crewes.org&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="507" LastActivityDate="2014-06-16T10:22:04.107" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2133" PostTypeId="1" AcceptedAnswerId="2135" CreationDate="2014-06-16T07:34:10.950" Score="17" ViewCount="7245" Body="&lt;p&gt;In the northern hemisphere, July and August are the hottest months statistically&lt;sup&gt;1&lt;/sup&gt;, but the days start shortening after June 21st. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this just because the Northern Hemisphere keeps heating up after June 21st (just like the hottest part of a day is not when the sun is highest, but some hours later), or are other effects at play?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt; To my limited experience, Europe specifically, but maybe other northern parts as well. And the questions goes for other months in the southern hemisphere, of course.&lt;/p&gt;&#xA;" OwnerUserId="595" OwnerDisplayName="Jan Doggen" LastEditorUserId="20" LastEditDate="2014-08-24T17:49:45.017" LastActivityDate="2014-08-24T17:49:45.017" Title="July/August hottest months (northern hemisphere): because of continued warming or other effects?" Tags="|meteorology|temperature|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2134" PostTypeId="2" ParentId="2133" CreationDate="2014-06-16T09:06:44.570" Score="8" Body="&lt;p&gt;The reason for this is, as you pointed, the same than for day hours being the hottest after noon:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The atmosphere (and the sea) in July is hotter than in June, so even when you are getting less and less solar radiation, the effect is accumulative, and the atmosphere gets hotter and hotter. Only when the sum of the heat input (sunlight) plus the heat loss (radiation) gets negative, at the end of August, atmosphere starts to cold.&lt;/p&gt;&#xA;" OwnerDisplayName="Envite" LastActivityDate="2014-06-16T09:06:44.570" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2135" PostTypeId="2" ParentId="2133" CreationDate="2014-06-16T15:59:12.707" Score="19" Body="&lt;p&gt;The amount of surface heating from the sun is a function of time of year and latitude.  You are aware of the dependence on the time of year with the sun over the equator at the equinoxes and ~ $\pm$23$^\circ$ N at the solstices.  The varying position of the sun overhead means the projection of a solid angle from the sun onto the surface of the earth will vary as well.  This just means that when the sun is low, the energy in a &quot;beam&quot; of sunlight is spread over a very large area and warming will be reduced.  This is why a bright sunny day in the winter cannot provide the same heating as the bright sunny day in the summer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Surface energy loss is a function of the temperature of the surface, and atmospheric energy loss is a function of the local atmospheric temperature.  There are some complications here, namely clouds and greenhouse gases that prevent some radiative losses.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the summer solstice when days are long and the sun is at its highest it is easy to understand that we are getting more energy than we are losing, and the days should be warm.  What isn't so apparent is that after the days start shortening and the sun lowering in the sky that the days continue to warm.  This is simply because we are still getting more energy than we are losing.  It isn't until the energy losses (which happen 24 hours a day, regardless of day/night) finally overcome our energy gains (which only happen when the sun is out) that the days will start to cool.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/ieWRG.gif&quot; alt=&quot;Annual temperature cycle&quot;&gt;&lt;br&gt;&#xA;&lt;sub&gt;From www.atmos.washington.edu&lt;/sub&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This image is from the northern hemisphere, but it is unclear what latitude it is for.  The summer solstice is the maximum in solar insolation and the winter solstice the minimum.  Radiative losses increase with temperature, and it is the point at which temperature has risen enough such that the loss is equal to the (diminishing) solar input.  This is where the maximum temperature will occur.  The lag between the solstice and the max temperature will vary with latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As mentioned in a comment in the other answer, large bodies of water exaggerate this seasonal lag in temperature.  This is for the same reasons as for land, with the added effect of the large heat capacity of water (about 3x that of land). &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;You see the same effect in daytime maximum and minimum temperatures where (barring anything but solar influence) the daily max is often in the late afternoon and the daily min is often just before sunrise.  This is the same reasoning as above, just on a daily scale rather than seasonal.  The sun is overhead at solar noon (this varies with local noon based on longitude, time zone (daylight saving time)) but continues to provide solar heating after solar noon.  It isn't until the radiative losses overcome the radiative gains (afternoon to late afternoon) that the temperature will drop.  Likewise when the sun goes down temperatures will cool down until the sum comes back up. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/U7pwh.gif&quot; alt=&quot;Daily temperature variation&quot;&gt;&#xA;&lt;sub&gt;From www.vsc.edu&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-06-16T15:59:12.707" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2136" PostTypeId="1" CreationDate="2014-06-16T19:18:01.613" Score="11" ViewCount="713" Body="&lt;p&gt;According to Rodgers (2000) equation 2.80&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;d_s = \mathrm{tr}(\mathbf{A})&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $d_s$ is the number of degrees of freedom for the signal, tr denotes the trace, and $A$ is the averaging kernel matrix.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm trying to properly understand this.  For example, is it theoretically possible for the averaging kernel to have mainly or even exclusively off-diagonal elements?  In practice, this would mean that the retrieved state at height $h$ would correspond to the true state at height $h+1$, if we take remote sounding of an atmospheric column as an example.  In such a (admittedly contrived) example, we could get $d_s=0$, although we do have information in the measurement — it's just displaced.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this situation possible?  If yes, does $d_s$ tell the whole story as for the information content in the measurement?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&#xA;Clive D. Rodgers, Inverse methods for atmospheric sounding, Theory and Practice. ©2000 World Scientific Publishing Co., London, UK.&#xA;&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2014-06-16T19:24:38.740" LastActivityDate="2015-06-14T17:08:43.407" Title="Are the elements of an averaging kernel matrix always centered on the diagonal, or can they be exclusively off-diagonal in rare cases?" Tags="|remote-sensing|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="2137" PostTypeId="1" AcceptedAnswerId="2138" CreationDate="2014-06-16T22:28:12.200" Score="4" ViewCount="841" Body="&lt;p&gt;I was of the notion that as we get deeper into the Earth, it gets hotter and hotter. If so, how can there be huge oceans (they seem bigger than our Pacific) exist at such a place? If so, what are the possible implications of this discovery in shaping our understanding of the planet? I'm very curious to find out.&lt;/p&gt;&#xA;" OwnerUserId="596" LastEditorUserId="67" LastEditDate="2014-06-17T02:39:09.197" LastActivityDate="2014-06-17T02:39:09.197" Title="What are the implications of the recent discovery that huge oceans exist close to the mantle of the Earth?" Tags="|ocean|geodynamics|geochemistry|mineralogy|" AnswerCount="1" CommentCount="2" ClosedDate="2014-06-20T17:41:48.240" ContentLicense="CC BY-SA 3.0" />
  <row Id="2138" PostTypeId="2" ParentId="2137" CreationDate="2014-06-17T00:00:28.077" Score="16" Body="&lt;p&gt;I am going to assume that you are referring to recent new stories with titles like &quot;Rare Diamond Confirms That Earth's Mantle Holds an Ocean's Worth of Water&quot; (&lt;a href=&quot;http://www.scientificamerican.com/article/rare-diamond-confirms-that-earths-mantle-holds-an-oceans-worth-of-water/&quot;&gt;Scientific America&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These articles are referring to research published in Nature: &lt;a href=&quot;http://www.nature.com/nature/journal/v507/n7491/full/nature13080.html&quot;&gt;Pearson, D. G. et al. (2014)&lt;/a&gt;.  The researchers found an inclusion of ringwoodite inside a diamond.  Here is a quote from the Nature article about the paper...&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Using infrared spectroscopy, Pearson’s team found that its tiny fleck&#xA;  of ringwoodite contained about 1% water by weight.  “That may not&#xA;  sound like much,” Pearson says, “but when you realize how much&#xA;  ringwoodite there is, the transition zone could hold as much water as&#xA;  all the Earth’s oceans put together.”&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This doesn't mean that there is a liquid ocean of water within the transition zone.  There are minerals that are considered &quot;hydrated&quot; because they contain hydroxide ions.  Examples of these are the serpentine group and micas.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ringwoodite can contain hydroxide ions within its structure, and these ions are the &quot;water&quot; that was measured.  If you were to lower the pressure, and increase the temperature, the water would be liberated from the mineral.  The point is that there are not huge oceans of liquid water within the mantle of the Earth; the water is locked up in the structure of certain minerals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are interesting implications from this research discussed in the Nature News article about the research.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/news/tiny-diamond-impurity-reveals-water-riches-of-deep-earth-1.14862&quot;&gt;Nature News Article&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="156" LastActivityDate="2014-06-17T00:00:28.077" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2139" PostTypeId="7" CreationDate="2014-06-17T04:24:47.953" Score="0" Body="&lt;ul&gt;&#xA;    &lt;li&gt;Specific issues with earth science&lt;/li&gt;&#xA;    &lt;li&gt;Real problems or questions that you’ve encountered&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="-1" LastEditorUserId="20" LastEditDate="2014-06-17T04:24:47.953" LastActivityDate="2014-06-17T04:24:47.953" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2140" PostTypeId="1" CreationDate="2014-06-17T08:32:55.260" Score="12" ViewCount="209" Body="&lt;p&gt;I often need to calculate heat balances for large biogas plants, an important factor is outside temperature. I normally use the weather data from &lt;a href=&quot;http://klimadiagramme.de/&quot;&gt;Klimadiagramme.de&lt;/a&gt; where I can find the mean monthly temperature and precipitation. This allows me to calculate the heat demand of my plant for a given month reasonably well. However, I also need to know extreme weather. I'm not sure what the metric here is, but I'm not looking for &quot;the coldest night in the last 100 years&quot; but &quot;this was the coldest average over 2-3 days in the last x years&quot; or something similiar. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, what is a good, free source of climate data that gives me information about extreme weather events as described?&lt;/p&gt;&#xA;" OwnerUserId="117" LastEditorUserId="20" LastEditDate="2014-07-04T01:34:54.050" LastActivityDate="2014-08-07T18:26:38.603" Title="What is a source of worldwide temperature data that also includes extreme weather?" Tags="|meteorology|climate|weather|open-data|" AnswerCount="2" CommentCount="7" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2141" PostTypeId="2" ParentId="2131" CreationDate="2014-06-17T14:48:17.670" Score="3" Body="&lt;p&gt;While the context and specifics would likely vary from site to site, the situation along the Gaza strip may be due to contamination of the Mediterranean Sea.  I am unsure of natural levels of Nitrate in ocean water, but I know that it is possible to contaminate water, independent of it's salinity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nitrate, like other water-soluble ions, ultimately is transported from the land to the oceans via the hydrologic cycle.  Waste from marine organisms also likely contributes nitrate.  T&lt;a href=&quot;http://www.soest.hawaii.edu/oceanography/faculty/chrism/COCA/Hot_Topics_files/Patey%20et%20al.,%202008%20%20review.pdf%29&quot; rel=&quot;nofollow&quot;&gt;his paper&lt;/a&gt; talks on the content of nitrate in ocean water. For more information on the various major constituents of sea water, check out &lt;a href=&quot;http://www.seafriends.org.nz/oceano/seawater.htm&quot; rel=&quot;nofollow&quot;&gt;this site&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There has been &lt;a href=&quot;http://www.al-monitor.com/pulse/originals/2013/07/sewage-gaza-beach-environment.html#&quot; rel=&quot;nofollow&quot;&gt;reported incidence&lt;/a&gt; of sewage draining into the Mediterranean, which would explain nitrate contamination in conjunction with sea-water intrusion. &lt;/p&gt;&#xA;" OwnerUserId="510" LastActivityDate="2014-06-17T14:48:17.670" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2142" PostTypeId="2" ParentId="2126" CreationDate="2014-06-18T03:51:20.553" Score="5" Body="&lt;p&gt;Yes high ozone levels are bad for human health and plant development.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Integral to your question is the natural high ozone concentrations at altitudes where you are near the tropopause.  The stratosphere has a lot of ozone and it gets entrained to the air around high elevation mountains quite often.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could read what the US EPA has to say about ground level ozone: &lt;a href=&quot;http://www.epa.gov/airquality/ozonepollution/&quot; rel=&quot;nofollow&quot;&gt;http://www.epa.gov/airquality/ozonepollution/&lt;/a&gt; which is relevant in terms of the health effects and the ecyosystem effects links.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It says: &quot;Breathing ozone can trigger a variety of health problems including chest pain, coughing, throat irritation, and congestion. It can worsen bronchitis, emphysema, and asthma. Ground level ozone also can reduce lung function and inflame the linings of the lungs. Repeated exposure may permanently scar lung tissue.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The National Ambient Air Quality Standards for ozone is 75 ppbV for an 8-hr average.  This means that if a county has 4 days per year with exceedances of the 8-hr avg threshold (over a 3-yr average), the air quality does not meet the Federal standard.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2014-11-25T15:35:25.577" LastActivityDate="2014-11-25T15:35:25.577" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2143" PostTypeId="1" CreationDate="2014-06-18T09:52:11.050" Score="12" ViewCount="221" Body="&lt;p&gt;First, what is the probability distribution of fault throw displacement. Uniform distribution seems unlikely, since then small changes would add up to huge huge elevation differences that require a large amount of by erosion to reduce. But the same holds for a Gaussian. Are there any other mechanisms that limits these large differences, like gravity pull-back and pressure from the magma? How can these be described in terms of free-fall, damping etc?&lt;/p&gt;&#xA;" OwnerUserId="601" LastEditorUserId="124" LastEditDate="2014-08-10T10:03:33.847" LastActivityDate="2014-08-14T05:19:21.543" Title="Probability distribution of fault throw displacement and height limiting mechanisms" Tags="|geophysics|seismology|plate-tectonics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2144" PostTypeId="1" AcceptedAnswerId="2145" CreationDate="2014-06-19T19:31:44.063" Score="11" ViewCount="3728" Body="&lt;p&gt;In the Northern Hemisphere, do surface winds around the center of a hurricane move counterclockwise and inward or counterclockwise and outward? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm guessing they move inward.&lt;/p&gt;&#xA;" OwnerUserId="605" LastEditorUserId="284" LastEditDate="2014-06-19T22:56:35.137" LastActivityDate="2015-05-25T22:22:08.927" Title="Winds in a northern hemisphere hurricane" Tags="|meteorology|atmosphere|weather|tropical-cyclone|wind|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2145" PostTypeId="2" ParentId="2144" CreationDate="2014-06-19T20:24:02.800" Score="10" Body="&lt;p&gt;The winds in a hurricane move cyclonic and inward at the surface and anti-cyclonic and outward in the upper troposphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cyclonic winds are counter-clockwise in the northern hemisphere and clockwise in the southern hemisphere.  Anti-cyclonic is the opposite of cyclonic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;https://earthscience.stackexchange.com/a/749/64&quot;&gt;this answer&lt;/a&gt; for a more detailed discussion of the winds within a tropical cyclone.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-06-19T20:29:49.160" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2146" PostTypeId="1" CreationDate="2014-06-19T20:26:48.680" Score="11" ViewCount="2549" Body="&lt;p&gt;I wanted to know if volcanic ash deposits found in the geologic record are most useful in correlating the age of rock layers if the volcanic ash was distributed over a large area during a short period of time or large area during a long period of time&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was thinking over a long period of time because it helps more with determining a rocks age.&lt;/p&gt;&#xA;" OwnerUserId="605" LastEditorUserId="87" LastEditDate="2014-06-20T08:36:49.397" LastActivityDate="2014-06-21T10:51:45.773" Title="Determining a rock age using volcanic ash layer" Tags="|geology|volcanology|sedimentology|stratigraphy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2147" PostTypeId="1" AcceptedAnswerId="2156" CreationDate="2014-06-20T06:26:25.517" Score="23" ViewCount="4718" Body="&lt;p&gt;I'm aware of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Oklo&quot;&gt;Oklo reactor&lt;/a&gt; and other &lt;a href=&quot;http://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor&quot;&gt;natural nuclear fission reactors&lt;/a&gt;, in which geological processes can lead to the formation of a sustained, self-regulating uranium fission reactor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it also possible for geological processes (on Earth or elsewhere) to form a critical mass of radioactive elements, leading to a runaway chain reaction and resulting in a nuclear explosion? I realise that nowadays the proportion of ${}^{235}\mathrm{U}$ in uranium deposits is too small to achieve criticality, but if it was large enough in the past for the Oklo reactor to form then that seems to imply that it was high enough for uncontrolled fission to occur as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it likely that such an event has happened on Earth in the past (on the surface or in the interior), and if so is there any known geological evidence that suggests an actual instance of it?&lt;/p&gt;&#xA;" OwnerUserId="215" LastEditorUserId="4487" LastEditDate="2015-10-28T01:10:24.477" LastActivityDate="2019-01-01T13:39:33.213" Title="Natural nuclear explosions" Tags="|geophysics|geology|geochemistry|uranium|radioactivity|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2148" PostTypeId="2" ParentId="2146" CreationDate="2014-06-20T08:34:40.250" Score="8" Body="&lt;p&gt;The main interest of tephrochronology (i.e. dating sediments using volcanic ash layer) is specifically its instantaneity (relatively to geological timescale of course). It is precisely used for higher-resolution dating. An example would be the Kawakawa/Oruanui tephra from New Zealand which is a good isochronous marker bed at 26.5 ka, spread over 1500km, but represents probably only a few months of volcanic activity (see e. g. &lt;strong&gt;Manville &amp;amp; Wilson 2006&lt;/strong&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Important factors vis-à-vis the usefulness of a specific ash layer however are its geographical extent (a volcanic event that will spread an ash layer over a whole basin would be more useful in that it will be used to correlate a large number of sites together) and maybe its volume (you need a minimum amount of material to work with, I'll assume).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Reference: Manville V. &amp;amp; Wilson C. J. N., 2006. &lt;a href=&quot;http://dx.doi.org/10.1080/00288306.2004.9515074&quot;&gt;The 26.5 ka Oruanui eruption, New Zealand: A review of the roles of volcanism and climate in the post‐eruptive sedimentary response.&lt;/a&gt; New Zealand Journal of Geology and Geophysics, 47: 525-547. &lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-06-21T10:51:45.773" LastActivityDate="2014-06-21T10:51:45.773" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2149" PostTypeId="1" AcceptedAnswerId="2154" CreationDate="2014-06-20T14:27:06.140" Score="13" ViewCount="274" Body="&lt;p&gt;&lt;a href=&quot;http://www.nature.com/nature/journal/v426/n6968/full/nature02114.html#B7&quot;&gt;This paper&lt;/a&gt; here goes into some detail about how Mars' experiences its own form of 'ice ages' on a quasi periodic basis driven by the wobbling of its axis. The main mechanism outlined is that the stability of water ice on the surface increases with increased obliquity. This is in contrast to Earth when at high obliquity there is increased polar summer insolation leading to metling. What is the difference? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;On a more discussion based addition to the question, could factors such as ice albedo and other feedback loops play a similar role in Mars' ice ages that they do in Earth's ice ages?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;I have also asked this at the Astronomy stack exchange &lt;a href=&quot;https://astronomy.stackexchange.com/questions/3711/why-does-mars-experience-an-ice-age-at-high-axis-obliquity-when-earth-experi&quot;&gt;here&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="389" LastEditorUserId="389" LastEditDate="2014-06-20T15:00:21.890" LastActivityDate="2014-06-22T17:02:24.170" Title="Why does Mars' experience an 'ice age' at high axis obliquity, when Earth experiences an ice age at low axis obliquity" Tags="|climate|planetary-science|ice-age|mars|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2150" PostTypeId="1" CreationDate="2014-06-21T02:28:49.230" Score="8" ViewCount="107" Body="&lt;p&gt;I have some earthquake data with an attribute field call M and has values c, h , l , m or w.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is another one called Magnitude so I assume its not that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any ideas what M represents and what the codes mean?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;" OwnerUserId="607" LastActivityDate="2014-06-21T02:28:49.230" Title="Question about earthquake data attribute codes" Tags="|earthquakes|database|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2151" PostTypeId="2" ParentId="238" CreationDate="2014-06-21T04:47:09.040" Score="5" Body="&lt;p&gt;I am not not an expert in meteorology, but do study the chemistry involved in these types of events.  My understanding is that the folds in the tropopause generally occur below the front of the jet stream, when the potential vorticity is strong enough to transport stratospheric air down through the tropopause/inversion. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please see the relevant quote from Q. J. R. Meteorol. Soc. (2004), 130, pp. 1195–1212 doi: 10.1256/qj.03.21&#xA;Convective mixing in a tropopause fold&#xA;By H. J. REID and G. VAUGHAN∗&#xA;Institute of Mathematical and Physical Sciences, University of Wales, Aberystwyth, UK&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;&quot;Mixing between stratospheric and tropospheric air can occur most readily in deep&#xA;intrusions of stratospheric air into the troposphere, such as tropopause folds (Danielsen&#xA;1968). They occur because of the ageostrophic circulation at the jet entrance (Hoskins&#xA;1982) and coincide with the frontal zone beneath the jet. Deep folds can extend down to&#xA;the top of the boundary layer (Browell et al. 1987; Vaughan et al. 1994), while smaller&#xA;folds, extending only into the upper troposphere, are ubiquitous around the polar jet&#xA;stream (e.g. Vaughan et al. 2001). They also occur beneath the subtropical jet stream&#xA;(Gouget et al. 1996), where it has been suggested that mixing between the subtropical&#xA;fold and tropospheric air promotes the generation of new aerosol particles (Zahn et al.&#xA;2000). Turbulence within folds can result from shear instability beneath the jet (Pepler&#xA;et al. 1998; Hartjenstein 2000) or from convection extending up from the boundary&#xA;layer (Browning and Reynolds 1994).&quot;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for synoptic scale weather, I don't think a tropopause fold affects the synoptic scale weather events much, but are rather a part of the weather events.  The downward mixing of stratospheric air will introduce drier air, leading to lower humidity in the general vicinity.  Of course, ozone will be entrained into the tropopause as well, which has air quality implications.  And there are certainly feedbacks in the fold phenomena that will affect heat, radiation, and kinetic patterns... but the synoptic weather in the region is going to be more driven by the jet stream itself rather than a fold that may occur.  A meteorologist, though, might have better information on that.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2014-06-25T03:04:48.690" LastActivityDate="2014-06-25T03:04:48.690" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2154" PostTypeId="2" ParentId="2149" CreationDate="2014-06-22T17:02:24.170" Score="11" Body="&lt;p&gt;If I understood it correctly, the important point is the temperature difference between mars and earth. On earth increasing obliquity, as you wrote, leads to increased melting of ice, ie. you increase the amount of liquid water on earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On mars average temperatures even during summer are too low to allow for liquid water. Higher obliquity doesn't really lead to a melting of ice. It mainly increases sublimation thereby increasing the water content of the atmosphere also on lower latitudes. The water vapour freezes out and leads to ice shields extended to lower latitudes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in short, since temperatures on mars are too low to allow for liquid water, the extend of the ice cover is larger, when the ice receives increased insolation. &#xA;Whereas on earth the ice cover is larger when insolation is low, since it gains mass from the pool of liquid water.    &lt;/p&gt;&#xA;" OwnerUserId="526" LastActivityDate="2014-06-22T17:02:24.170" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2155" PostTypeId="1" AcceptedAnswerId="2157" CreationDate="2014-06-22T22:27:54.873" Score="13" ViewCount="1740" Body="&lt;p&gt;The media have variously reported that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Ninety-seven percent of climate scientists agree that climate-warming&#xA;  trends over the past century are very likely due to human activities.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Based on &lt;a href=&quot;http://iopscience.iop.org/1748-9326/8/2/024024/article&quot;&gt;this&lt;/a&gt; study. My question is, who are the 3%, who do not agree on anthropogenic global warming, and what are their main lines of reasoning? It seems that the fact that these scientists represent a small minority is simply an &quot;Argumentum ad populum&quot;, not a real refutation, and I'd like to learn more.&lt;/p&gt;&#xA;" OwnerUserId="614" LastActivityDate="2017-02-12T19:31:32.110" Title="Who are the 3% in the often cited &quot;97% of climate scientists&quot;?" Tags="|climate-change|climatology|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="2156" PostTypeId="2" ParentId="2147" CreationDate="2014-06-23T08:02:53.637" Score="20" Body="&lt;p&gt;This hypothesis has been studied &lt;a href=&quot;http://arxiv.org/pdf/1001.4243v2&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; as a possible explanation of selenogenesis (&lt;a href=&quot;https://en.wikipedia.org/wiki/Origin_of_the_Moon&quot; rel=&quot;noreferrer&quot;&gt;formation of the Moon&lt;/a&gt;). (&lt;em&gt;Forming the Moon from terrestrial silicate-rich material.&lt;/em&gt; R.J. de Meijer, V.F. Anisichkin, W. van Westrenen. 2013.)&lt;/p&gt;&#xA;&lt;p&gt;The only place cited as suitable for spontaneous criticality is the &lt;strong&gt;Core-Mantle Boundary&lt;/strong&gt; (&lt;a href=&quot;https://en.wikipedia.org/wiki/Core-mantle_boundary&quot; rel=&quot;noreferrer&quot;&gt;CMB&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The calculations above show that &lt;strong&gt;without additional concentration factors, &lt;span class=&quot;math-container&quot;&gt;$\mathrm{U}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\mathrm{Th}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\mathrm{Pu}$&lt;/span&gt; concentrations in the CMB are insufficient to reach criticality&lt;/strong&gt;. Additional concentrations can be achieved by a combination of two processes: growth of the relative concentration of the fissile materials by a transient pressure wave, induced by an impact at the Earth’s surface (Anisichkin, 1997; Voronin and Anisichkin, 2001), and/or the development of compositional heterogeneities (de Meijer and Van Westrenen, 2008).&lt;/p&gt;&#xA;&lt;p&gt;As shown by Voronin (2011) for fissile material at the CMB, an impact of a 100km- diameter asteroid can create a transient pressure increase of several TPa at the CMB, sufficient to concentrate fissile material from a subcritical to a supercritical condition followed by a nuclear explosion. Regarding the development of compositional heterogeneities, it should be noted that small-scale heterogeneities exist in the core-mantle boundary region even today (e.g., van der Hilst et al., 2007): volumes exhibiting both higher-than-average and lower-than-average wave propagation speeds, with diameters as small as 30 km, are now resolvable. Some studies suggest that the bottom of the mantle is partially molten today, forming a so-called ‘basal magma ocean’ (e.g. Williams and Garnero, 1996; Labrosse et al., 2007; Lee et al., 2010).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;For another take on natural nuclear explosions, see &lt;a href=&quot;http://www.lpi.usra.edu/meetings/lpsc2011/pdf/1097.pdf&quot; rel=&quot;noreferrer&quot;&gt;this paper&lt;/a&gt; (&lt;em&gt;Evidence for a large, natural, paleo-nuclear reactor on Mars.&lt;/em&gt; J. E. Brandenburg, Orbital Technologies Corporation. LPI 2011 Proceedings.), citing an anomaly in &lt;a href=&quot;https://en.wikipedia.org/wiki/Mare_Acidalium_quadrangle&quot; rel=&quot;noreferrer&quot;&gt;Mare Acidalium&lt;/a&gt; on Mars.&lt;/p&gt;&#xA;&lt;p&gt;It should be noted that nuclear explosions need both critical mass &lt;strong&gt;and&lt;/strong&gt; very low times of reactivity insertion. A &lt;a href=&quot;https://en.wikipedia.org/wiki/Gun-type_fission_weapon&quot; rel=&quot;noreferrer&quot;&gt;gun-type bomb&lt;/a&gt; would be the best analogy for low-yield natural explosions on the surface/in the crust, and it is very unlikely to have a naturally occurring acceleration hurl a uranium-rich boulder against a uranium-rich wall.&lt;/p&gt;&#xA;&lt;p&gt;To detect natural explosions on the surface, one would need to look for fused silica and anomalous &lt;span class=&quot;math-container&quot;&gt;$\mathrm{Xe}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\mathrm{Kr}$&lt;/span&gt; isotope ratios at the margins of our instruments' sensitivities.&lt;/p&gt;&#xA;" OwnerUserId="269" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-06-26T11:16:15.217" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2157" PostTypeId="2" ParentId="2155" CreationDate="2014-06-23T09:49:23.763" Score="24" Body="&lt;p&gt;As the abstract makes clear, the finding of Cook et al. (2013) is not really &quot;97% of researchers agree...&quot;; rather, it is &quot;97% of peer-reviewed publications agree&quot;. They didn't just go through some directory of climate researchers asking them what they thought. They read the abstracts of all 11,944 publications they found on the topic, and classified them according to what the abstract said. (The classification was blinded and crowdsourced -- read the paper for details.) As a secondary check, they asked the original researchers themselves to evaluate their own abstracts, presumably to control for any bias which Cook et al. might be bringing to the evaluation. The proportions of abstracts endorsing the consensus were 97.1% and 97.2% respectively for the two methodologies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that this isn't asking researchers anything about their own beliefs. Imagine that, for instance, Jane Q. Scientist privately believes that the earth will cool by 5°C in the next century, but that she hasn't found any solid data to back up this belief, so hasn't yet managed to publish anything supporting it. However, in 1998 she published a paper which provided evidence for anthropogenic global warming. Perhaps she now disbelieves the conclusions of that paper, but it remains in the literature because the data and reasoning were strong enough to stand up to peer review, no matter what the original author now thinks. In practice, of course, it's likely that scientists' personal beliefs will be similar to their published results, but I feel it's very important to stress that this study is &lt;em&gt;not&lt;/em&gt; an opinion poll -- it's an evaluation of the research itself. (The media can be a little sloppy in their reporting of this distinction.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, your question is a little misconstrued: we can't answer &quot;Who are the 3%?&quot; because the 3% are research articles rather than people. However, we &lt;em&gt;can&lt;/em&gt; ask &quot;Which are the 3% of published research abstracts which do not support the scientific consensus?&quot; And since Cook et al. (2013) is an open access paper with supporting data provided, you can easily answer this question for yourself: simply download the data file from the &lt;a href=&quot;http://iopscience.iop.org/1748-9326/8/2/024024/media&quot;&gt;supplementary data page&lt;/a&gt; and look at the papers with an endorsement rating of 5, 6, or 7. (It's in CSV format, so is easy to load into a spreadsheet or text editor.) Further supplementary data is available from &lt;a href=&quot;http://www.skepticalscience.com/tcp.php?t=home&quot;&gt;the project page at Skeptical Science&lt;/a&gt;, and replication of the research is actively encouraged. If you're interested in the actual people behind the 3% of &quot;non-consensus&quot; papers you can look at the author lists for those publications (though of course there's no guarantee that all those authors would still stand by all their conclusions).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suggest that you start your investigations by reading the paper itself. It's clear and concise, and will give you much more thorough information about the methodology and supporting data than I've been able to fit into this answer.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Cook, J., Nuccitelli, D., Green, S. A., Richardson, M., Winkler, B., Painting, R., ... &amp;amp; Skuce, A. (2013). Quantifying the consensus on anthropogenic global warming in the scientific literature. &lt;em&gt;Environmental Research Letters&lt;/em&gt;, 8(2), 024024.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2014-06-23T18:29:09.217" LastActivityDate="2014-06-23T18:29:09.217" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2158" PostTypeId="1" AcceptedAnswerId="2159" CreationDate="2014-06-24T10:27:50.263" Score="15" ViewCount="9410" Body="&lt;p&gt;Can I find the direction to land when I am in the middle of the ocean and can not see any land?&#xA;This is a theoretical question.&#xA;Any method that doesn't use over-technical methods such as smartphones and GPS will do.&#xA;Example: Ocean current direction, wind direction, fluctuation in temperature, etc.&lt;/p&gt;&#xA;" OwnerUserId="619" LastActivityDate="2017-03-29T13:20:00.717" Title="Is there a way to find the direction to land in the middle of an ocean?" Tags="|ocean|oceanography|ocean-currents|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2159" PostTypeId="2" ParentId="2158" CreationDate="2014-06-24T13:25:16.383" Score="12" Body="&lt;p&gt;Your best bet without modern tools would be a sextant and the proper maps for celestial navigation.  This is a time-tested and old method of navigation no longer in regular use, but it probably doesn't meet your &quot;no over-technical methods&quot; criterion as it requires a tool, maps and knowledge of its use.  If you only had knowledge of the constellations and a few stars (e.g. Polaris, the Sun) you could probably figure out what region of the globe you were on and make a best-guess as to the direction of land.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might be able to do a similar guess with surface winds, ocean surface flow and temperature to get a rough location but if any synoptic conditions are masked by storms or local anomalies then this will likely not work.  There are some semi-presistent weather features (e.g. the &lt;a href=&quot;http://forecast.weather.gov/glossary.php?word=bermuda%20high&quot;&gt;Bermuda high&lt;/a&gt;) that you could use along with knowledge of the general circulation that could potentially help you out.  You could make similar estimates with ocean current and temperature (if you have equipment to measure this), but I think this would only provide regional benefits and may not work everywhere you could find yourself.  These would also be marred by tropical convection (e.g. in the wake of a hurricane sea surface temperatures will be cooler than normal) and other storms.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-06-24T13:25:16.383" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2160" PostTypeId="1" CreationDate="2014-06-24T13:57:17.747" Score="3" ViewCount="69" Body="&lt;p&gt;E.g. IGCM, HadCM3, HadGEM1, GFDL CM, CGCM, CCSM, CFS, and ECHAM.&lt;/p&gt;&#xA;" OwnerUserId="10" LastActivityDate="2014-07-02T07:40:15.567" Title="Are there any studies comparing different climate models on how well they've forecasted the climate in the past?" Tags="|atmosphere|" AnswerCount="1" CommentCount="2" ClosedDate="2014-07-03T19:49:35.517" ContentLicense="CC BY-SA 3.0" />
  <row Id="2161" PostTypeId="1" CreationDate="2014-06-24T07:13:52.773" Score="17" ViewCount="6096" Body="&lt;p&gt;Being this my first questions on this .SE I hope that the topic is appropriate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've been told that 99% of the living species on earth live in between -200m and 800m above sea level, this made me just wonder how much of earth surface lies in this elevation span, but I couldn't find the answer googling. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Does anybody have a source to check what percentage of dry land has sea level elevation lower than 1 km (or 800m, or in between -200m and 800m...)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) How should I interpret the information given to me about the number of living species? I would just say for the 99% of the living species the intersection between the &quot;natural habitat&quot; and the altitude &quot;-200m - 800m&quot; is non empty, is it correct? Is there a source where I can check this information?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks in advance!!&lt;/p&gt;&#xA;" OwnerUserId="622" OwnerDisplayName="Giovanni De Gaetano" LastActivityDate="2018-03-22T21:11:07.777" Title="Percentage of dry land surface with sea level elevation lower than 1 km" Tags="|geography|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="2162" PostTypeId="1" AcceptedAnswerId="2170" CreationDate="2014-06-25T04:37:12.177" Score="24" ViewCount="1341" Body="&lt;p&gt;Was there a significant bias between the ensemble of climate models and the long-term temperature trends?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What about spatial patterns?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="543" LastEditDate="2017-01-29T17:50:08.067" LastActivityDate="2017-01-29T17:50:08.067" Title="How good were climate models of the 1990s at predicting the global temperature trends of the 2000s/2010s?" Tags="|meteorology|atmosphere|climate|climate-change|climate-models|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2163" PostTypeId="1" AcceptedAnswerId="2269" CreationDate="2014-06-25T06:06:26.890" Score="11" ViewCount="458" Body="&lt;p&gt;In an area of frequent thunderstorms, I notice a 'crack or whoosh' sound if a strike is nearby but little or no thunder. Yet I can hear for 30 seconds or so after a distant flash when the thunder first is heard, the sound starts at a high frequency and then evolves into a deep rumble that can shake the walls. It approaches the sub-sonic. What is the relationship between the distance and the energy of the strike?&lt;/p&gt;&#xA;" OwnerUserId="621" LastEditorUserId="269" LastEditDate="2014-06-25T13:23:12.153" LastActivityDate="2016-05-23T07:51:22.300" Title="Propagation of sound after lightning" Tags="|meteorology|thunderstorm|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2164" PostTypeId="1" CreationDate="2014-06-25T08:30:21.080" Score="13" ViewCount="464" Body="&lt;p&gt;Having read &lt;a href=&quot;https://earthscience.stackexchange.com/questions/1023/how-does-the-precession-of-the-earths-apses-affect-climate&quot;&gt;this answer&lt;/a&gt; about the precession of the equinoxes and how it affects Earth's climate, my understanding was that only because of the differing affect of continental and maritime insolation that precession of the equinoxes was a factor in ice-sheet growth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if all the continents magically switched to be reflected in the equator (i.e. now we have a Southern Hemisphere dominated by continents), would we now have ice-ages at the 'opposite' time (i.e. short SOUTHERN hemisphere summers)? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;And if all the continents moved to be equally spread out about the globe, precession of the equinoxes would play no factor in the ice-ages at all? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the mechanism that causes this effect? i.e. Why do continents determine the ice growth, and not the oceans? The response in the previous question that: &quot;Continents show more seasonal variability&quot; is a little vague. &lt;/p&gt;&#xA;" OwnerUserId="389" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-07-03T13:02:45.327" Title="Are ice-ages dependent on an un-equal distribution of land-masses?" Tags="|climate|ice-age|milankovitch-cycles|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2165" PostTypeId="1" CreationDate="2014-06-25T16:19:32.003" Score="3" ViewCount="50" Body="&lt;p&gt;And how does their temporal resolution compare with proxies for air temperatures? Can they forecast ocean temperatures in all regions of the ocean equally well, or only some regions of the ocean?&lt;/p&gt;&#xA;" OwnerUserId="10" LastActivityDate="2014-06-25T16:19:32.003" Title="What are some proxies for ocean temperatures/heat?" Tags="|oceanography|" AnswerCount="0" CommentCount="0" ClosedDate="2014-06-30T14:06:36.027" ContentLicense="CC BY-SA 3.0" />
  <row Id="2166" PostTypeId="1" CreationDate="2014-06-25T16:21:46.580" Score="6" ViewCount="65" Body="&lt;p&gt;I'm talking about evidence from both proxy records in the last 50,000 years (if possible) and the recent past (if also possible)&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="725" LastEditDate="2014-12-08T05:48:55.910" LastActivityDate="2014-12-08T05:48:55.910" Title="Does the time-lagged correlation between $\ce{CO2}$ and ocean temperature have a shorter timelag than the one between $\ce{CO2}$ and air temperature?" Tags="|atmosphere|climate|paleoclimatology|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2167" PostTypeId="1" CreationDate="2014-06-25T16:22:58.683" Score="5" ViewCount="323" Body="&lt;p&gt;Is there a time-lagged correlation with CO&lt;sub&gt;2&lt;/sub&gt; levels preceding temperature? Does the time lag change from time to time?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="725" LastEditDate="2014-12-08T05:47:39.303" LastActivityDate="2014-12-08T05:47:39.303" Title="What is the time-lagged correlation between historical $\ce{CO2}$ records from ice cores and global temperature records?" Tags="|atmosphere|climate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2168" PostTypeId="1" CreationDate="2014-06-25T16:27:25.020" Score="5" ViewCount="2057" Body="&lt;p&gt;If so, would the acid snow just be as damaging?&lt;/p&gt;&#xA;" OwnerUserId="10" LastActivityDate="2014-07-02T10:37:33.800" Title="If there's acid rain, is there such thing as acid snow?" Tags="|weather|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2169" PostTypeId="1" CreationDate="2014-06-25T16:29:38.660" Score="4" ViewCount="843" Body="&lt;p&gt;Would it look like any other region of the planet?&lt;/p&gt;&#xA;" OwnerUserId="10" LastActivityDate="2014-06-25T16:29:38.660" Title="If all the sand in the Saharan Desert were to be removed, what would the remaining landscape look like?" Tags="|geology|" AnswerCount="0" CommentCount="2" ClosedDate="2014-10-11T13:00:44.893" ContentLicense="CC BY-SA 3.0" />
  <row Id="2170" PostTypeId="2" ParentId="2162" CreationDate="2014-06-25T20:01:36.367" Score="17" Body="&lt;p&gt;You might take a look at &lt;a href=&quot;http://www.climatechange2013.org/images/report/WG1AR5_TS_FINAL.pdf&quot; rel=&quot;noreferrer&quot;&gt;the Technical Summary of the most recent IPCC Assessment Report (5).&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Thematic Focus Element #3 is &amp;quot;Comparing Projections from Previous IPCC Assessments with Observations&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;It says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;h3&gt;Global Mean Temperature Anomaly&lt;/h3&gt;&#xA;&lt;p&gt;Relative to the 1961–1990 mean, the GMST anomaly has been positive and&#xA;larger than 0.25°C since 2001. Observations are generally well within&#xA;the range of the extent of the earlier IPCC projections (TFE.3,&#xA;Figure1, middle left) This is also true for the Coupled Model&#xA;Intercomparison Project Phase 5 (CMIP5) results (TFE.3, Figure 1;&#xA;middle right) in the sense that the observed record lies within the&#xA;range of the model projections, but on the lower end of the plume. Mt&#xA;Pinatubo erupted in 1991 (see FAQ 11.2 for discussion of how volcanoes&#xA;impact the climate system), leading to a brief period of relative&#xA;global mean cooling during the early 1990s. The IPCC First, Second and&#xA;Third Assessment Reports (FAR, SAR and TAR) did not include the&#xA;effects of volcanic eruptions and thus failed to include the cooling&#xA;associated with the Pinatubo eruption. AR4 and AR5, however, did&#xA;include the effects from volcanoes and did simulate successfully the&#xA;associated cooling. During 1995–2000 the global mean temperature&#xA;anomaly was quite variable—a significant fraction of this variability&#xA;was due to the large El Niño in 1997–1998 and the strong back-to-back&#xA;La Niñas in 1999–2001. The projections associated with these&#xA;assessment reports do not attempt to capture the actual evolution of&#xA;these El Niño and La Niña events, but include them as a source of&#xA;uncertainty due to natural variability as encompassed by, for example,&#xA;the range given by the individual CMIP3 and CMIP5 simulations and&#xA;projection (TFE.3, Figure 1). The grey wedge in TFE.3, Figure 1&#xA;(middle right) corresponds to the indicative &lt;em&gt;likely&lt;/em&gt; range for annual&#xA;temperatures, which is determined from the Representative&#xA;Concentration Pathways (RCPs) assessed value for the 20-year mean&#xA;2016–2035 (see discussion of Figure TS.14 and Section 11.3.6 for&#xA;details). From 1998 to 2012 the observational estimates have largely&#xA;been on the low end of the range given by the scenarios alone in&#xA;previous assessment reports and CMIP3 and CMIP5 projections. {2.4; Box&#xA;9.2}&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I've attached an image as well from that summary:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/rQPb0.png&quot; alt=&quot;previous IPCC temperature performance&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;Estimated changes in the&#xA;observed globally and annually averaged surface temperature anomaly&#xA;relative to 1961–1990 (in °C) since 1950 compared with the range of&#xA;projections from the previous IPCC assessments. Values are harmonized&#xA;to start from the same value at 1990. Observed global annual&#xA;temperature anomaly, relative to 1961–1990, from three data sets is&#xA;shown as squares and smoothed time series as solid lines from the&#xA;Hadley Centre/Climatic Research Unit gridded surface temperature data&#xA;set 4 (HadCRUT4; bright green), Merged Land–Ocean Surface Temperature&#xA;Analysis (MLOST; warm mustard) and Goddard Institute for Space Studies&#xA;Surface Temperature Analysis (GISTEMP; dark blue) data sets. The&#xA;coloured shading shows the projected range of global annual mean near&#xA;surface temperature change from 1990 to 2035 for models used in FAR&#xA;(Figure 6.11), SAR (Figure 19 in the TS of IPCC 1996), TAR (full range&#xA;of TAR, Figure 9.13(b)). TAR results are based on the simple climate&#xA;model analyses presented in this assessment and not on the individual&#xA;full three-dimensional climate model simulations. For the AR4 results&#xA;are presented as single model runs of the CMIP3 ensemble for the&#xA;historical period from 1950 to 2000 (light grey lines) and for three&#xA;SRES scenarios (A2, A1B and B1) from 2001 to 2035. For the three SRES&#xA;scenarios the bars show the CMIP3 ensemble mean and the likely range&#xA;given by –40 % to +60% of the mean as assessed in Chapter 10 of AR4.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-08-24T01:18:14.290" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2171" PostTypeId="1" AcceptedAnswerId="2172" CreationDate="2014-06-26T03:00:38.700" Score="7" ViewCount="148" Body="&lt;p&gt;I heard that at one time the Sahara desert was cropped in wheat for the Roman Empire, and that cropping without adding back to the soil was what caused the desert to form. I also heard that this is going on in the U.S. (in the Great Plains, etc.). Really? Seems odd that the amount of rainfall would differ based on the health of the soil.&lt;/p&gt;&#xA;" OwnerUserId="611" LastEditorUserId="64" LastEditDate="2014-06-26T04:16:28.637" LastActivityDate="2014-06-26T04:16:28.637" Title="Does over-cropping large areas really change the amount of rainfall?" Tags="|meteorology|weather|precipitation|desert|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2172" PostTypeId="2" ParentId="2171" CreationDate="2014-06-26T04:15:51.210" Score="5" Body="&lt;p&gt;For an example of how bad agricultural practices can cause soil loss and end up with dust and sand, see the conditions that preceded the dust bowl in the USA.  Certain crops are bad for soil and if not rotated will eventually deplete the soil of nutrients leading to no crops.  With nothing holding the soil in place (roots) it will erode. The Sahara has other ill effects going on, such as synoptic scale atmospheric descent (interaction from the Walker Circulation and the Hadley cell) which promotes dry, warm conditions.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not sure that rainfall will vary based on soil health, but one avenue to look into is soil moisture and other sources of water.  Rain begins as water vapor and that water vapor comes from evaporation (from bodies of water, entrainment), evapotranspiration (from soil and plants) and advection (blown in with the wind).  If the predominant flow does not bring in moisture and you lose the ability to hold water in the soil, this could conceivably locally reduce water vapor mixing ratios and impact precipitation.  That is just a guess and it would be worth searching the literature (you can freely download AMS articles older than 2 years old and &lt;a href=&quot;http://journals.ametsoc.org/&quot; rel=&quot;noreferrer&quot;&gt;search them here&lt;/a&gt;). &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-06-26T04:15:51.210" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2173" PostTypeId="1" CreationDate="2014-06-26T08:56:49.313" Score="26" ViewCount="986" Body="&lt;p&gt;Earth, Titan and Venus all have large amounts of $\mathrm{N_2}$ in their atmospheres. (In the case of Venus it's a small proportion, but Venus' atmosphere is very thick, and the total mass of $\mathrm{N_2}$ is greater than Earth's.) However, other planets and moons, and Mars in particular, have hardly any. Why is this? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\mathrm{N_2}$ is a relatively light molecule, so I suppose it could be lost to space from smaller bodies. Did Mars start with a thick nitrogen atmosphere and then lose it? Or alternatively, is there some process that produced lots of $\mathrm{N_2}$ on Earth, Titan and Venus, which didn't occur on Mars or the other outer Solar system moons? If so, what is this process likely to be?&lt;/p&gt;&#xA;" OwnerUserId="215" LastEditorDisplayName="user889" LastEditDate="2014-12-20T22:50:58.553" LastActivityDate="2019-05-17T10:33:59.937" Title="Why do some planets have lots of $\mathrm{N_2}$ and others none?" Tags="|atmosphere|planetary-science|nitrogen|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2175" PostTypeId="1" AcceptedAnswerId="2180" CreationDate="2014-06-26T16:08:50.170" Score="6" ViewCount="293" Body="&lt;p&gt;So the moon is full of helium-3.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since it's a gas in the moon's vacuum... Why doesn't it escape?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="431" LastEditDate="2014-07-08T16:55:51.677" LastActivityDate="2014-07-08T16:55:51.677" Title="Why does helium-3 stay in the moon and not escape from it?" Tags="|planetary-science|moon|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2176" PostTypeId="1" CreationDate="2014-06-26T19:46:44.963" Score="12" ViewCount="3589" Body="&lt;p&gt;Will it increase the size of it? (perhaps by increasing the extent of the &lt;a href=&quot;http://en.wikipedia.org/wiki/Hadley_cell&quot;&gt;Hadley Cells&lt;/a&gt;)?&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="1109" LastEditDate="2014-12-04T11:09:43.020" LastActivityDate="2020-10-27T07:06:54.853" Title="How will climate change affect the extent of the Sahara Desert?" Tags="|climate|climate-change|desert|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2177" PostTypeId="1" CreationDate="2014-06-26T19:48:05.503" Score="6" ViewCount="7413" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Sacramento,_California&quot;&gt;http://en.wikipedia.org/wiki/Sacramento,_California&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It has high winter temperatures and high summer temperatures too.&lt;/p&gt;&#xA;" OwnerUserId="10" LastActivityDate="2014-12-12T10:41:39.143" Title="Why is Sacramento so warm for its latitude?" Tags="|weather|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2178" PostTypeId="1" CreationDate="2014-06-26T22:26:12.210" Score="7" ViewCount="432" Body="&lt;p&gt;Interested in this since I sometimes look down on the clouds in the plane, and wonder if some of the reflected UV-A radiation might damage my eyes.&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorDisplayName="user889" LastEditDate="2015-02-14T10:01:54.193" LastActivityDate="2018-10-02T12:28:16.253" Title="What reflects UV radiation more: stratus clouds or cumulus clouds?" Tags="|clouds|atmospheric-radiation|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2180" PostTypeId="2" ParentId="2175" CreationDate="2014-06-27T01:19:45.160" Score="13" Body="&lt;p&gt;The Moon is not &quot;full&quot; of helium-3. &lt;sup&gt;3&lt;/sup&gt;He is at most fifty parts per billion of the lunar regolith&lt;sup&gt;1&lt;/sup&gt; and that &quot;high&quot; concentration pertains only to permanently shadowed craters. The Moon is bombarded by a steady stream of helium-3 while sunlit. Some of this incoming helium-3 is temporarily embedded in the lunar regolith. Without this steady supply, the helium-3 content would dissipate at a temperature-dependent rate proportional to the amount of helium-3 in the lunar regolith.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The quantity $q(t)$ of in a cubic meter of lunar regolith is thus dictated by a simple differential equation, $\dot q(t) = \alpha(t) - \beta(T)q(t)$. Time averaging the bombardment and escape rates yields $\dot {\bar q}(t) = \bar{\alpha} - \beta(\bar T)q(t)$. This differential equation yields a steady state value of $\bar q = \bar{\alpha}/\beta(\bar T)$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;&lt;sup&gt;1&lt;/sup&gt; Cooks, &quot;&lt;sup&gt;3&lt;/sup&gt;He in permanently shadowed lunar polar surfaces&quot;, &lt;em&gt;Icarus&lt;/em&gt;, 206:2 778-779 (2010).&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-06-27T01:19:45.160" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2182" PostTypeId="1" CreationDate="2014-06-27T03:58:00.667" Score="5" ViewCount="89" Body="&lt;p&gt;And the atmosphere as well?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a follow-up question to &lt;a href=&quot;https://www.quora.com/What-else-has-been-left-out-of-climatology/answer/Konstantin-Zahariev?&amp;amp;share=1&quot; rel=&quot;nofollow&quot;&gt;https://www.quora.com/What-else-has-been-left-out-of-climatology/answer/Konstantin-Zahariev?&amp;amp;share=1&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="111" LastEditDate="2015-07-07T18:10:10.870" LastActivityDate="2015-07-07T18:10:10.870" Title="How do mesoscale eddies in the ocean transport heat between different layers of the ocean?" Tags="|ocean|eddies|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2183" PostTypeId="1" AcceptedAnswerId="2184" CreationDate="2014-06-27T12:43:05.667" Score="11" ViewCount="6470" Body="&lt;p&gt;I thought Auroras are only visible in the North Pole and South Pole, but recently, I found out that Auroras can be seen in areas of the world closer to the equator.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An example is that in the year 1909, a great storm of Auroras were seen in Japan and other countries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This made me wonder: could an Aurora be seen in equatorial regions, too?&lt;/p&gt;&#xA;" OwnerUserId="628" LastEditorUserId="20" LastEditDate="2015-04-04T00:29:59.717" LastActivityDate="2015-04-04T00:29:59.717" Title="Is it possible to see Auroras from the equatorial region?" Tags="|equator|auroras|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2184" PostTypeId="2" ParentId="2183" CreationDate="2014-06-27T15:24:28.173" Score="12" Body="&lt;p&gt;Quoting from the Wikipedia article on the &lt;a href=&quot;http://en.wikipedia.org/wiki/Solar_storm_of_1859&quot;&gt;Solar Storm of 1859&lt;/a&gt;;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;On September 1–2, 1859, the largest recorded geomagnetic storm occurred. Aurorae were seen around the world, those in the northern hemisphere even as far south as the Caribbean; those over the Rocky Mountains were so bright that their glow awoke gold miners, who began preparing breakfast because they thought it was morning.[2] People who happened to be awake in the northeastern US could read a newspaper by the aurora's light.[4] The aurora was visible as far from the poles as Cuba and Hawaii.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, it didn't quite make it to the equator, but it came very close.  There is no physical reason why you can't get aurora at the equator, but it takes a lot of very energetic particles being ejected by the sun over a brief period. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, as I mentioned in my comment, a solar storm of that magnitude would wipe out most of the Earth's electric grids.  Even the telegraph systems of the 1800's couldn't survive.  Another quote from the Wikipedia article;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Telegraph systems all over Europe and North America failed, in some cases giving telegraph operators electric shocks.[6] Telegraph pylons threw sparks.[7] Some telegraph systems continued to send and receive messages despite having been disconnected from their power supplies.[8]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="53" LastEditorUserId="53" LastEditDate="2014-06-27T20:00:06.150" LastActivityDate="2014-06-27T20:00:06.150" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2185" PostTypeId="1" CreationDate="2014-06-28T01:12:17.860" Score="7" ViewCount="203" Body="&lt;p&gt;I live in British Columbia, and a hot topic right now is the proposed Enbridge pipeline. One aspect in particular gets a lot of attention, the risk of a &quot;bad oil spill&quot;. Is there a clear guideline as to what exactly constitutes a bad oil spill? How much oil must be spilled? Is it dependent on what type of oil is spilled and in what area, populated by what species? Looking for some general guidelines.&lt;/p&gt;&#xA;" OwnerUserId="629" LastEditorUserId="124" LastEditDate="2014-06-29T15:03:35.273" LastActivityDate="2014-07-07T16:56:14.850" Title="How bad is a &quot;bad&quot; oil spill?" Tags="|pollution|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2186" PostTypeId="1" AcceptedAnswerId="2198" CreationDate="2014-06-28T04:15:19.930" Score="10" ViewCount="4978" Body="&lt;p&gt;It is known that cities tend to be warmer than the surrounding landscapes, and this is known as the &quot;urban heat island effect&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the summer there is greater heat output from air conditioning systems. In the winter there is greater heat output from heating systems (heat pumps aside). Are these a substantial contributor to the effect, or are there other causes?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Summary of question: What are the causes of the urban heat island effect, and are there specific times of the year when the effect is stronger?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="124" LastEditDate="2014-07-01T23:50:59.953" LastActivityDate="2014-07-02T20:28:32.053" Title="Is the urban heat island effect stronger during a particular season or part of the year?" Tags="|meteorology|climate|weather|urban-climate|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2187" PostTypeId="1" AcceptedAnswerId="2188" CreationDate="2014-06-28T09:00:48.410" Score="20" ViewCount="2137" Body="&lt;p&gt;I was wondering if there really was some natural variation that keeps getting cited by climate-change skeptics that predicts a warming? The only such variation I can think of would be the milankovitch cycles, however this predicts &lt;em&gt;cooling&lt;/em&gt; not warming at present (as far as I recall).&lt;/p&gt;&#xA;" OwnerUserId="389" LastEditorUserId="543" LastEditDate="2016-01-29T08:36:06.007" LastActivityDate="2016-11-25T13:44:17.477" Title="What is the 'natural variation' in global temperature that climate-change skeptics mention?" Tags="|climate-change|" AnswerCount="4" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2188" PostTypeId="2" ParentId="2187" CreationDate="2014-06-28T14:14:09.250" Score="17" Body="&lt;p&gt;First off, let me preface this answer with a disclaimer: I do not deny climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From what I've read, the skeptics for the most part don't claim to have an alternative explanation for the recent warming. Their arguments (not mine!) are fourfold:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The recent warming doesn't exist, is natural, or is just noise. The tiny half degree warming we've seen in the last 40 years is a tiny blip on the huge changes that have occurred in the past.&lt;/li&gt;&#xA;&lt;li&gt;Climate change is a natural occurrence. The climate has changed historically naturally by huge amounts, much bigger than the tiny half degree warming we've seen in the last 40 years. &lt;/li&gt;&#xA;&lt;li&gt;Predicting the weather after ten days is a fool's errand. Predicting climate is worse than a fool's errand. It can't be done.&lt;/li&gt;&#xA;&lt;li&gt;Even if things have warmed up in the last forty years, one thing is certain: It's not CO&lt;sub&gt;2&lt;/sub&gt;. That a tiny trace gas could possibly drive the climate is laughable.&#xA;&lt;br&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Those are not my arguments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regard to point #1,&lt;br&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/7ENS6.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7ENS6.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;Source: &lt;a href=&quot;http://www.wmo.int/pages/mediacentre/press_releases/pr_976_en.html&quot; rel=&quot;noreferrer&quot;&gt;World Meteorological Organization Press Release No. 976: 2001-2010, A Decade of Climate Extremes&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The above image speaks for itself. The global temperature change over the last forty years is very real, and is not noise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;With regard to point #2, yes the climate has changed in the past, and by huge amounts. We've had everything from snowball Earth to dinosaurs roaming the Arctic. And the point is? This argument is akin to a farmer taking a trip to the Grand Canyon and upon seeing what damage nature can do decides to forgo contour plowing and other anti-erosion farming techniques.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That the farmer's field might turn into a mountain or be washed out to sea several millions of years from now is irrelevant. What's relevant is that his good or bad practices have an impact on the world food supply. That nature can do far worse does not negate those bad farming practices. Bad farming practices are bad for humanity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Getting back to climate change, if higher global temperatures are bad for humanity, it doesn't matter matter one bit how close ice came to the equator or how far north dinosaurs roamed in the past. What matters is that modern humanity is sensitive to climate change, be it natural or induced by humans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;With regard to point #3, yes, weather becomes chaotic after ten days or so. That does not mean that climate is chaotic, and if it is, the ~ten day Lyapunov time of the weather does not mean that climate also has a ten day Lyapunov time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regard to point #4, it is CO&lt;sub&gt;2&lt;/sub&gt;. It was amusing to follow the skeptic response to Richard Muller's Berkeley Earth Surface Temperature project. Muller was a self-proclaimed skeptic, and he was going to prove those leftist climatologists wrong. The skeptic community cheered at the start. &#xA;&quot;He's going to prove them wrong!&quot; A funny thing happened on the way to proving them wrong: He proved them to be correct. Muller was an honest scientist in this regard. His own work caused him to switch from being a skeptic to ascribing to AGW.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2016-01-21T11:45:02.237" LastActivityDate="2016-01-21T11:45:02.237" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2189" PostTypeId="1" CreationDate="2014-06-29T08:13:21.000" Score="13" ViewCount="492" Body="&lt;p&gt;I know that there are techniques that help scientists determine the age of a rock. But is it also possible to determine how long ago a rock was broken? For example, how could we date the formation of the fracture surface in the photograph below?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/4kjfb.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="633" LastEditorDisplayName="user20559" LastEditDate="2021-05-14T10:46:00.127" LastActivityDate="2024-02-13T19:12:46.673" Title="How to determine how long ago a rock was broken?" Tags="|geology|rocks|petrology|geochronology|" AnswerCount="3" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2190" PostTypeId="1" AcceptedAnswerId="2191" CreationDate="2014-06-29T18:51:34.850" Score="6" ViewCount="5312" Body="&lt;p&gt;Could somebody tell me what the &quot;C&quot; signifies in the unit mg C L&lt;sup&gt;-1&lt;/sup&gt;? I was wondering if it stood for concentration but it seems redundant as litres are mentioned. Thanks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The paper which uses the unit is &quot;Dissolved Organic Carbon Thresholds Affect Mercury Bioaccumulation in Arctic Lakes&quot; by French et al. 2014.&lt;/p&gt;&#xA;" OwnerUserId="580" LastEditorUserId="725" LastEditDate="2014-12-09T05:41:50.107" LastActivityDate="2014-12-09T05:41:50.107" Title="Meaning of the C in the unit &quot;mg C L-1&quot;" Tags="|hydrology|terminology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2191" PostTypeId="2" ParentId="2190" CreationDate="2014-06-29T19:08:44.973" Score="11" Body="&lt;p&gt;Given the subject matter of the paper, I'd assume that it stands for carbon, and the whole expression refers to milligrams of carbon (or organic carbon) per litre of lake water.&lt;/p&gt;&#xA;" OwnerUserId="94" LastActivityDate="2014-06-29T19:08:44.973" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2192" PostTypeId="2" ParentId="873" CreationDate="2014-06-30T02:22:25.310" Score="3" Body="&lt;p&gt;Radiative efficiency is the radiative forcing per unit change in halocarbon mixing ratio.  Radiative Efficiency assumes that the Radiative Forcing is linear in mixing ratio—this is normally appropriate in the case of small perturbations in mixing ratio about current concentrations and is also appropriate for CFCs.  To calculate it requires a radiative transfer model, which includes both analytical and theoretical contributions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The diagram shown in Hodnebrog et al.: &quot;Global warming potentials and radiative efficiencies of halocarbons and related compounds: A comprehensive review&quot; in Reviews of Geophysics&#xA;( &lt;a href=&quot;http://dx.doi.org/10.1002/rog.20013&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://dx.doi.org/10.1002/rog.20013&lt;/a&gt; ) explains how radiative efficiency is calculated and is pasted below: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/ig2AR.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2014-06-30T02:22:25.310" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2193" PostTypeId="2" ParentId="2190" CreationDate="2014-06-30T02:36:32.210" Score="3" Body="&lt;p&gt;If the &quot;C&quot; stands for carbon,  then the &quot;unit&quot; doesn't conform to the SI standard, which states that units should not contain extraneous information. That information should instead be in the name of the relevant quantity. See &lt;a href=&quot;http://physics.nist.gov/Pubs/SP811/sec07.html&quot; rel=&quot;nofollow&quot;&gt;http://physics.nist.gov/Pubs/SP811/sec07.html&lt;/a&gt; for more information. &lt;/p&gt;&#xA;" OwnerUserId="30" LastActivityDate="2014-06-30T02:36:32.210" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2194" PostTypeId="2" ParentId="2164" CreationDate="2014-06-30T13:27:09.137" Score="0" Body="&lt;p&gt;I'm not sure of the HOW MUCH the effect of precession of equinoxes compares to the land-ocean distribution. So its hard to answer say what will happen if we reorder the land distribution. But i can try to answer the part of your question &quot;Why continents show more seasonal variability&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason will be the huge difference between their heat capacities. The effective heat capacity of land is much less than that of the oceans on a seasonal time scale&lt;a href=&quot;http://stratus.astr.ucl.ac.be/textbook/chapter2_node7_1.xml&quot; rel=&quot;nofollow&quot;&gt;[1]&lt;/a&gt;. Hence land heats up and cools down rather quickly, whereas the ocean water does not vary in temperature so much and stays much closer to the mean values. So, with same amount of insolation, land will have much higher or lower temperature as compared to ocean. In case of a cooling trend, the lower temperatures tends to increase ice cover over land which results in increasing the albedo, and hence reducing the amount of solar energy absorbed, leading to more cooling.  This positive feedback should be applicable to oceans as well, but on land its just much faster and thus leads to formation of ice sheets over it over extended cooling periods.   &lt;/p&gt;&#xA;" OwnerUserId="206" LastActivityDate="2014-06-30T13:27:09.137" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2195" PostTypeId="2" ParentId="2161" CreationDate="2014-06-30T13:58:40.300" Score="11" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/I06TG.png&quot; alt=&quot;enter image description here&quot;&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Fig. 2.4 of &lt;a href=&quot;https://books.google.com/books?id=vqgfH9DXXNAC&amp;amp;printsec=frontcover&amp;amp;dq=Deep-Sea%20Biology:%20A%20Natural%20History%20of%20Organisms%20at%20the%20Deep-Sea%20Floor&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwix-sPbjYDaAhWCZd8KHQ1xDsEQ6AEIJzAA#v=onepage&amp;amp;q=Deep-Sea%20Biology%3A%20A%20Natural%20History%20of%20Organisms%20at%20the%20Deep-Sea%20Floor&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;Deep-Sea Biology: A Natural History of Organisms at the Deep-Sea Floor&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;8.3% of the Earth's surface is above 1 kilometer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This corresponds to about 29% of the land area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So 71% of the land area is below 1 km.&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2018-03-22T14:11:47.430" LastActivityDate="2018-03-22T14:11:47.430" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2196" PostTypeId="2" ParentId="2187" CreationDate="2014-06-30T14:29:15.597" Score="2" Body="&lt;p&gt;Many natural cycles are known and understood even though &quot;skeptics&quot; like to point to them. For example, we can predict Milankovitch cycles, and we have good solar records for over 200 years. Although we might not necessarily know the magnitude of these effects a priori, we can look for these patterns in the climate record. eg. Does the Earth get warmer when the sun becomes more energetic, and get cooler when it becomes less energetic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We do see these effects in the Earth's climate (let's face it, it would a big surprise if the Earth did not get warmer when the Sun got warmer!), but they cannot account for all of these changes. For example, when the Sun might become less energetic the Earth does not cool as much as it warmed when the sun became more energetic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fOaxh.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fOaxh.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;em&gt;Heat-trapping emissions (greenhouse gases) far outweigh the effects of other drivers acting on Earth’s climate&lt;/em&gt;. Source: Hansen et al. 2005, Figure adapted by Union of Concerned Scientists&lt;sup&gt;*&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;* Hansen, J., L. Nazarenko, R. Ruedy, M. Sato, J. Willis, A. Del Genio, D. Koch, A. Lacis, K. Lo, S. Menon, T. Novakov, J. Perlwitz, G. Russell, G.A. Schmidt, and N. Tausnev. 2005. Earth’s energy imbalance: Confirmation and implications. Science 308:1431-1435&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorUserId="595" LastEditDate="2016-11-25T13:44:17.477" LastActivityDate="2016-11-25T13:44:17.477" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2198" PostTypeId="2" ParentId="2186" CreationDate="2014-07-01T16:15:31.903" Score="6" Body="&lt;p&gt;As with so many concepts in geography, I don't think there is a definitive answer -- it would very likely vary from city to city and from year to year. Urban heat island (UHI) effect is affected by so many different variables, such as albedo (reflectivity of surfaces), specific heat of the materials receiving and releasing radiation from the sun, thermal conduction into the ground, cloud cover, wind, and as you mentioned, anthropogenic heat production. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Throughout the year in a city with four distinct seasons, most of these variables change independently of each other (except for probably the specific heat of the materials). For instance, in a hypothetical city that receives a great deal of snow, albedo might be much higher in winter due to the high reflectivity of snow covering low-reflectivity surfaces (such as asphalt, roofs, etc.), which might reduce its contribution to UHI by causing fewer surfaces to absorb radiation from the sun. However, as mentioned in the question, anthropogenic contributions to UHI Effect might be higher in winter in the hypothetical city from latent heat from buildings, water/sewer pipes, vehicles, and so on. Further, wind patterns might shift in winter, bringing in more cool air in winter rather than summer, which would counter the increase from the anthropogenic sources.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, impacts from urban heat island are actually generally most pronounced during dusk, which is when much of that short-wave radiation from the sun (which was being stored all day in the sun) is released as long-wave radiation. With that in mind, another factor that could contribute is day-length. Many cities with four distinct seasons are in the mid-latitudes, which have variable day lengths between the seasons. Longer daylight in summer, then, would suggest that the UHI Effect would be worse in summer, as there would be more time for the surfaces to absorb short-wave radiation from the sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Great question - sorry for not definitively answering it. It appears there are some gaps and conflicts in the limited research on this topic. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A grad student at UMN suggests that UHI effect is worse in winter (without really explaining why), while &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/qj.49710845502/pdf&quot; rel=&quot;nofollow&quot;&gt;TR Oke suggests&lt;/a&gt; it is worse in summer, while James Voogt &lt;a href=&quot;http://www.actionbioscience.org/environment/voogt.html&quot; rel=&quot;nofollow&quot;&gt; suggests&lt;/a&gt; that UHI effect is generally stronger in summer and winter compared to spring and autumn (in the mid-latitudes).&lt;/p&gt;&#xA;" OwnerUserId="636" LastEditorUserId="636" LastEditDate="2014-07-02T18:20:37.240" LastActivityDate="2014-07-02T18:20:37.240" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2199" PostTypeId="1" CreationDate="2014-07-01T18:46:39.547" Score="9" ViewCount="543" Body="&lt;p&gt;I have a dataset &lt;a href=&quot;http://www.earth-syst-dynam.net/4/219/2013/esd-4-219-2013.pdf&quot;&gt;(The ISIMIP interpolation of CMIP5 output)&lt;/a&gt; that contains daily values of the following variables:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt; air_temperature (C)&#xA; air_temperature_max (C)&#xA; air_temperature_mmin (C)&#xA; relative_humidity (%)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;There are other variables (wind, downwelling long/short wave radiation, precipitation) that I suspect would not be useful for a first order approximation)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would be an appropriate way to downscale from daily to hourly values? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have an algorithm to do this when daily $rh_{max}$ and $rh_{min}$ are given. This assumes a peak $rh$ at 10AM and uses cosine to cycle between max and min&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$rh_{scale} \leftarrow \dfrac{1}{2}(\cos(2 * \pi * (0:23 - 2) / 24) + 1)$$ &#xA;$$RH \leftarrow rh_{min} + rh_{scale} * (rh_{max} - rh_{min})$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly, I get hourly temperature $t$ thus:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$t = t_{min} + \dfrac{1}{2}(\sin(2*pi*(0:23 - 10) / 24) + 1) * (t_{max} - t_{min})$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it is not clear how I can do this when mean RH is given. I know this is difficult, and there are likely many ways of bringing in other data sets, but I would like a simple first-order approximation that is better than assuming that RH is constant within each day.&lt;/p&gt;&#xA;" OwnerUserId="174" LastEditorUserId="64" LastEditDate="2014-07-02T03:09:04.887" LastActivityDate="2014-07-02T03:30:40.763" Title="How can I downscale daily values of relative humidity?" Tags="|meteorology|atmosphere|temperature|humidity|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2200" PostTypeId="2" ParentId="2185" CreationDate="2014-07-02T00:44:53.590" Score="2" Body="&lt;p&gt;An example of a &quot;bad&quot; (or at least notorious) oil spill was that of the &lt;a href=&quot;http://en.wikipedia.org/wiki/Exxon_Valdez&quot; rel=&quot;nofollow&quot;&gt;Exxon Valdez&lt;/a&gt; in 1989 in Alaska. It was variously estimated at between one-quarter and three quarters of a million barrels of spillage. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sensitivity of it was due to the fact that it took place in the Prince William Sound (near land) instead of on the open ocean, and greatly affected wildlife.&lt;/p&gt;&#xA;" OwnerUserId="42" LastActivityDate="2014-07-02T00:44:53.590" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2201" PostTypeId="2" ParentId="2199" CreationDate="2014-07-02T03:30:40.763" Score="3" Body="&lt;p&gt;Your approach to calculate an hourly temperature and relative humidity independently could be problematic, as these variables are dependent on one another.  I'd be interested to see a plot of one such day of $t$ and $rh$ and then to calculate the water vapor mixing ratio or dewpoint from your values and see how it varies in response and whether it is realistic looking.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If all you have in mean $rh$ and and a min/max temperature, one approach might be to derive a mean temperature and then from that a mean water vapor mixing ratio.  This mixing ratio can vary through evaporation, condensation, boundary layer mixing, etc, but for a rough approximation you could assume it is constant.  If you assume a constant mixing ratio and a temperature profile (e.g. your sinusoidal assumption) you could calculate the $rh$ profile for the day.  Note that you'll have to assure that your temperature curve does not cool below the dewpoint. You have the mean $rh$ as a crosscheck for this method and can use that to iteratively adjust your method for obtaining the water vapor mixing ratio.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your diurnal temperature profile will vary based on latitude, time of year, proximity to large bodies of water, and weather.  If you discount the weather you can get by with your sinusoidal approximation with your minimum temperature at local sunrise and your maximum temperature in the mid to late afternoon.  The amplitude of the sine wave will be dependent on the your location (e.g. coastal locations will have small amplitude changes and inland desert locations will have large changes).  With a constant water vapor mixing ratio this will yield the highest RH at the temperature min at sunrise and the lowest RH in the mid afternoon. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you can provide a $t_{max}$, $t_{min}$ and $\overline{rh}$ and a rough idea of where on earth your are looking at, I can run some numbers and provide more detail on this method. &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-07-02T03:30:40.763" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2202" PostTypeId="1" AcceptedAnswerId="2445" CreationDate="2014-07-02T06:01:17.880" Score="10" ViewCount="1376" Body="&lt;p&gt;Tetens coefficients appear in a few meteorological/climatological models that I've been looking at,for example &lt;a href=&quot;http://apsrunet.apsim.info/svn/apsim/tags/Apsim70/Model/MicroMet/MicroMet.for&quot; rel=&quot;nofollow&quot;&gt;APSIM&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;svp_A = 6.106&#xA;svp_B = 17.27&#xA;svp_C = 237.3&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;These same values appear in at least two other models, but I can't find any documentation about what they represent, or where they come from. What are these numbers?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt; &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2000JD900061/pdf&quot; rel=&quot;nofollow&quot;&gt;Oroud, I. M., 2001, &lt;em&gt;Dynamics of evaporation from saline water bodies&lt;/em&gt;&lt;/a&gt; uses these constants and references &lt;em&gt;Tetens, O. 1930 &lt;strong&gt;&quot;Uber einige meteorologische Begriffe.&quot;&lt;/strong&gt; Z. Geophys. 6: 297-309&lt;/em&gt;, but that text doesn't appear to be available online, or in my university's library.&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="56" LastEditDate="2014-09-04T03:41:40.147" LastActivityDate="2014-09-04T03:45:25.443" Title="What are Tetens coefficients?" Tags="|meteorology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2203" PostTypeId="2" ParentId="2160" CreationDate="2014-07-02T07:34:38.743" Score="0" Body="&lt;p&gt;Yes. The biggest and broadest are the &lt;strong&gt;Palaeoclimate Modelling Intercomparison Projects (PMIP)&lt;/strong&gt;, which are the past-climate equivalent of the Climate Model Intercomparison Projects (CMIP).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The latest is &lt;a href=&quot;https://pmip3.lsce.ipsl.fr/&quot; rel=&quot;nofollow&quot;&gt;PMIP3&lt;/a&gt;. It includes &lt;a href=&quot;https://wiki.lsce.ipsl.fr/pmip3/doku.php/pmip3%3adatabase%3astatus&quot; rel=&quot;nofollow&quot;&gt;many of the same models&lt;/a&gt; that were used in CMIP5, as well as other models that are more focussed on representing past climates. The &quot;&lt;a href=&quot;https://pmip3.lsce.ipsl.fr/overview/&quot; rel=&quot;nofollow&quot;&gt;overview&lt;/a&gt;&quot; link on the PMIP3 page gives an indication of what the project covers, including experiments into the impacts of climate forcings, as well as benchmarking and comparison of models (e.g. quantitative and qualitative assessments of model performance over past climates).&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="56" LastEditDate="2014-07-02T07:40:15.567" LastActivityDate="2014-07-02T07:40:15.567" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2204" PostTypeId="2" ParentId="2140" CreationDate="2014-07-02T08:05:32.160" Score="6" Body="&lt;p&gt;&lt;a href=&quot;http://www.climdex.org/datasets.html&quot;&gt;CLIMDEX&lt;/a&gt;, the &quot;Datasets for Indices of Climate Extremes&quot; is probably the closest you are going to get, for any pre-computed indices. The 27 indices it includes are listed &lt;a href=&quot;http://www.climdex.org/indices.html&quot;&gt;on the indices page&lt;/a&gt; of that site.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, it doesn't include anything like &quot;coldest 3-day average per year&quot;, let alone &quot;coldest 3-day average over the last 5 years&quot;. I doubt there would be any pre-built dataset with exactly that index, and there is unlikely to be online tool that would calculate unusual indices, because the data sets are &lt;em&gt;huge&lt;/em&gt; (&lt;a href=&quot;http://www.cru.uea.ac.uk/cru/data/temperature/&quot;&gt;HadCRUt4&lt;/a&gt; is 20MB for &lt;em&gt;monthly&lt;/em&gt; data over the last 150 years), and unusual indices would have to be calculated on the fly - something that's just not feasible on the 'web.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would guess that you'd have to calculate that yourself, from a raw daily temperature dataset. Unfortunately, I don't think such a thing exists on a global scale. However, a reanalysis product like the &lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html&quot;&gt;NCEP/NCAR Reanalysis&lt;/a&gt; is probably good enough for your purposes. However, you'll need to be familiar with large data analysis - the daily surface temperature dataset is over 450MB. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Depending on your exact usage requirements, you might be better off just looking up some of the historical records for neighbouring meteorological stations and using those.&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2014-07-02T08:05:32.160" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2205" PostTypeId="2" ParentId="2168" CreationDate="2014-07-02T10:37:33.800" Score="1" Body="&lt;p&gt;As &lt;a href=&quot;http://www.reddit.com/r/askscience/comments/1wkrty/if_theres_acid_rain_is_there_such_thing_as_acid/cf2zim4&quot; rel=&quot;nofollow&quot;&gt;explained by user voltaic at reddit&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Yes, there is, and it can be more of a problem than acid rain.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;For one, when snow is falling it spends more time travelling through&#xA;  the atmosphere before hitting the ground than rain. As a result of&#xA;  this, it has more time to collect pollutants, and can become more&#xA;  acidic than typical acid rain for the same region. There's additional&#xA;  factors that complicate this however, such as the solubility of the&#xA;  pollutant, the temperature and the water content of the snow, etc.&#xA;  (e.g. warmer snow which is more &quot;wet&quot; is going to dissolve more than&#xA;  cooler, drier snow.)&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Once the snow hits the ground, the dissolved pollutants are going to&#xA;  stay in solution, or trapped within the crystalline structure of the&#xA;  snow until it melts. Because of this, snow can pile up and then thaw,&#xA;  releasing all the pollutants and acidic water in a relatively short&#xA;  amount of time. This can have fairly substantial effects on the&#xA;  environment.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;You can read a bit more about this here:&lt;/p&gt;&#xA;  &#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;&lt;a href=&quot;http://www.elmhurst.edu/~chm/vchembook/191acidsnow.html&quot; rel=&quot;nofollow&quot;&gt;http://www.elmhurst.edu/~chm/vchembook/191acidsnow.html&lt;/a&gt;&lt;/li&gt;&#xA;  &lt;li&gt;&lt;a href=&quot;http://dwb4.unl.edu/Chem/CHEM869V/CHEM869VLinks/www.qesn.meq.gouv.qc.ca/cc/acidrain/info6.htm&quot; rel=&quot;nofollow&quot;&gt;http://dwb4.unl.edu/Chem/CHEM869V/CHEM869VLinks/www.qesn.meq.gouv.qc.ca/cc/acidrain/info6.htm&lt;/a&gt;&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Acid snow is also mentioned in passing on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Acid_rain&quot; rel=&quot;nofollow&quot;&gt;acid rain wikipedia page&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &quot;fairly substantial effects on the environment&quot;, as described by the links above, largely involve a large release of acid during the spring thaw, which effectively releases all of the acid built up over the winter in a relatively short period. This can result in lowered pH in waterways, which can affect fish, amphibians and crustaceans.&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2014-07-02T10:37:33.800" CommentCount="0" CommunityOwnedDate="2014-07-02T10:37:33.800" ContentLicense="CC BY-SA 3.0" />
  <row Id="2206" PostTypeId="2" ParentId="2167" CreationDate="2014-07-02T13:34:02.433" Score="5" Body="&lt;p&gt;From &lt;a href=&quot;https://en.wikipedia.org/wiki/Global_warming_controversy#Greenhouse_gases&quot; rel=&quot;noreferrer&quot;&gt;wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;Studies of the Vostok ice core show that at the &quot;beginning of the deglaciations, the CO$_2$ increase either was in phase or lagged by less than ~1000 years with respect to the Antarctic temperature, whereas it clearly lagged behind the temperature at the onset of the glaciations&quot;.$^{[1]}$ Recent warming is followed by carbon dioxide levels with only a 5 months delay.$^{[2]}$ The time lag has been used to argue that the current rise in CO$_2$ is a result of warming and not a cause. While it is generally agreed that variations before the industrial age are mostly timed by astronomical forcing,$^{[3]}$ a main part of current warming is found to be timed by anthropogenic releases of CO$_2$, having a much closer time relation not observed in the past (thus returning the argument to the importance of human CO$_2$ emissions). Analysis of carbon isotopes in atmospheric CO$_2$ shows that the recent observed CO$_2$ increase cannot have come from the oceans, volcanoes, or the biosphere, and thus is not a response to rising temperatures as would be required if the same processes creating past lags were active now.$^{[4]}$&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://cdiac.esd.ornl.gov/trends/co2/vostok.htm&quot; rel=&quot;noreferrer&quot;&gt;Historical carbon dioxide record from the Vostok ice core&lt;/a&gt; - Carbon Dioxide Information Analysis Center, 2003.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Spencer R. Weart, 2006, &lt;a href=&quot;http://www.aip.org/history/climate/index.html&quot; rel=&quot;noreferrer&quot;&gt;The Discovery of Global Warming&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Kuo et. al., 1990, &lt;a href=&quot;http://www.nature.com/nature/journal/v343/n6260/abs/343709a0.html&quot; rel=&quot;noreferrer&quot;&gt;Coherence established between atmospheric carbon dioxide and global temperature&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://www.physicstoday.org/vol-58/iss-5/p16a.html&quot; rel=&quot;noreferrer&quot;&gt;More Notes on Global Warming&lt;/a&gt; - Physics Today, 2005&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="56" LastActivityDate="2014-07-02T13:34:02.433" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2207" PostTypeId="2" ParentId="1023" CreationDate="2014-07-02T16:06:21.667" Score="4" Body="&lt;p&gt;The precessional effect on climate is caused due to two factors:&#xA;&lt;br&gt;(1) Axial Precession&#xA;&lt;br&gt;(2) Apsidal Precession&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The precession of the apses doesn't cause a change in climatic state by itself. However, this motion is in the same sense as the axial precession (gyroscopic motion of the earth's axes). This effect reduces the period of precession from 26kyr to ~21kyr.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Combined, the two effects cause what is known as the precession of the equinoxes. If you consider this a cyclic process, the two extreme precessional configurations are shown below:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/TbI1M.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See NH++. In this configuration, NH summer is at perihelion. Thus, during NH summer, earth is closest to the sun, and therefore Northern hemisphere has a strong summer. During NH winter, earth is farthest from the sun, therefore Northern Hemisphere has a weak winter as well. Thus in this precessional configuration, the earth has extreme seasons in the Northern Hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now see SH++. In this configuration, SH summer is at perihelion. Thus, during SH summer, earth is closest to the sun, and therefore the southern hemisphere has a strong summer. During SH winter, earth is farthest from the sun, therefore southern Hemisphere has a weak winter as well. Thus in this precessional configuration, the earth has extreme seasons in the southern Hemisphere.&lt;/p&gt;&#xA;" OwnerUserId="639" LastActivityDate="2014-07-02T16:06:21.667" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2208" PostTypeId="2" ParentId="2164" CreationDate="2014-07-02T16:11:12.767" Score="2" Body="&lt;p&gt;First, let us try to understand how precession affects climate:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The precessional effect on climate is caused due to two factors:-&#xA;&lt;br&gt;(1) Axial Precession&#xA;&lt;br&gt;(2) Apsidal Precession&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The precession of the apses doesn't cause a change in climatic state by itself. However, this motion is in the same sense as the axial precession (gyroscopic motion of the earth's axes). This effect reduces the period of precession from 26kyr to ~21kyr.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Combined, the two effects cause what is known as the precession of the equinoxes. If you consider this a cyclic process, the two extreme precessional configurations are shown below:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/TbI1M.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See NH++. In this configuration, NH summer is at perihelion. Thus, during NH summer, earth is closest to the sun, and therefore Northern hemisphere has a strong summer. During NH winter, earth is farthest from the sun, therefore Northern Hemisphere has a weak winter as well. Thus in this precessional configuration, the earth has extreme seasons in the Northern Hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now see SH++. In this configuration, SH summer is at perihelion. Thus, during SH summer, earth is closest to the sun, and therefore the southern hemisphere has a strong summer. During SH winter, earth is farthest from the sun, therefore southern Hemisphere has a weak winter as well. Thus in this precessional configuration, the earth has extreme seasons in the southern Hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now coming to your question of how landmasses affect climate. If the earth was symmetric, even then ice-ages would have occurred at same times in the earth's history. However, their intensity would have differed due to the Northern Hemisphere land bias.&lt;/p&gt;&#xA;" OwnerUserId="639" LastEditorUserId="639" LastEditDate="2014-07-02T18:12:04.837" LastActivityDate="2014-07-02T18:12:04.837" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2209" PostTypeId="2" ParentId="2186" CreationDate="2014-07-02T16:24:26.413" Score="3" Body="&lt;p&gt;The urban heat island (UHI) effect scales with population of a metropolitan area... the bigger the city the larger the UHI effect.  UHI is not due to more heat being generated through anthropogenic activity (e.g. air conditioners) but rather it is primarily a land use change issue (e.g. from vegetative to urban).  Vegetation is able to regulate heat and moisture much better than concrete and building surfaces, which trap more heat during clear sky days and then radiate that heat throughout the night.  The urban heat island effect is strongest at night, when the daytime had significant direct heating of the surface (e.g. clear sky conditions), and when the atmospheric boundary layer temperature inversion is close enough to the ground to prevent ventilation / mixing with the air above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;http://en.wikipedia.org/wiki/Urban_heat_island&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/Urban_heat_island&lt;/a&gt; :&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;There are several causes of an urban heat island (UHI). The principal&#xA;  reason for the nighttime warming is that the short-wave radiation is&#xA;  still within the concrete, asphalt, and buildings that was absorbed&#xA;  during the day, unlike suburban and rural areas. This energy is then&#xA;  slowly released during the night as long-wave radiation, making&#xA;  cooling a slow process. Two other reasons are changes in the thermal&#xA;  properties of surface materials and lack of evapotranspiration (for&#xA;  example through lack of vegetation) in urban areas. With a decreased&#xA;  amount of vegetation, cities also lose the shade and cooling effect of&#xA;  trees, the low albedo of their leaves, and the removal of carbon&#xA;  dioxide. Materials commonly used in urban areas for pavement and&#xA;  roofs, such as concrete and asphalt, have significantly different&#xA;  thermal bulk properties (including heat capacity and thermal&#xA;  conductivity) and surface radiative properties (albedo and emissivity)&#xA;  than the surrounding rural areas. This causes a change in the energy&#xA;  balance of the urban area, often leading to higher temperatures than&#xA;  surrounding rural areas. Other causes of a UHI are due to geometric&#xA;  effects. The tall buildings within many urban areas provide multiple&#xA;  surfaces for the reflection and absorption of sunlight, increasing the&#xA;  efficiency with which urban areas are heated. This is called the&#xA;  &quot;urban canyon effect&quot;. Another effect of buildings is the blocking of&#xA;  wind, which also inhibits cooling by convection and pollution from&#xA;  dissipating. Waste heat from automobiles, air conditioning, industry,&#xA;  and other sources also contributes to the UHI. High levels of&#xA;  pollution in urban areas can also increase the UHI, as many forms of&#xA;  pollution change the radiative properties of the atmosphere. As UHI&#xA;  raises the temperature of cities, it will also increase the&#xA;  concentration of ozone in the air, which is a greenhouse gas. Ozone&#xA;  concentrations will increase because it is a secondary gas, aided by&#xA;  an increase in temperature and sunlight.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;http://www.epa.gov/heatisland/about/index.htm&quot; rel=&quot;nofollow&quot;&gt;http://www.epa.gov/heatisland/about/index.htm&lt;/a&gt; it says: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;As urban areas develop, changes occur in their landscape. Buildings,&#xA;  roads, and other infrastructure replace open land and vegetation.&#xA;  Surfaces that were once permeable and moist become impermeable and&#xA;  dry. These changes cause urban regions to become warmer than their&#xA;  rural surroundings, forming an &quot;island&quot; of higher temperatures in the&#xA;  landscape. Heat islands occur on the surface and in the atmosphere. On&#xA;  a hot, sunny summer day, the sun can heat dry, exposed urban surfaces,&#xA;  such as roofs and pavement, to temperatures 50–90°F (27–50°C) hotter&#xA;  than the air, while shaded or moist surfaces—often in more rural&#xA;  surroundings—remain close to air temperatures. Surface urban heat&#xA;  islands are typically present day and night, but tend to be strongest&#xA;  during the day when the sun is shining. In contrast, atmospheric urban&#xA;  heat islands are often weak during the late morning and throughout the&#xA;  day and become more pronounced after sunset due to the slow release of&#xA;  heat from urban infrastructure. The annual mean air temperature of a&#xA;  city with 1 million people or more can be 1.8–5.4°F (1–3°C) warmer&#xA;  than its surroundings.3 On a clear, calm night, however, the&#xA;  temperature difference can be as much as 22°F (12°C).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="39" LastEditDate="2014-07-02T20:28:32.053" LastActivityDate="2014-07-02T20:28:32.053" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2210" PostTypeId="1" CreationDate="2014-07-02T17:27:31.633" Score="10" ViewCount="166" Body="&lt;p&gt;Now that it's thunderstorm season here in New Hampshire, it would be nice to be able to find out what the vertical wind shear is like at the altitudes that affect thunderstorm formation, to guess whether they'll form.  Once cumulus clouds have started to form, it's usually easy to see by just looking up.  But when planning one's day in the morning, there often aren't big enough clouds yet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone direct me to an easy-to-use source for this?&lt;/p&gt;&#xA;" OwnerUserId="640" LastEditorUserId="124" LastEditDate="2014-07-02T20:27:04.383" LastActivityDate="2014-07-03T15:06:52.907" Title="Is there a convenient place to get vertical wind shear info for my location?" Tags="|meteorology|weather-forecasting|thunderstorm|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2211" PostTypeId="2" ParentId="2210" CreationDate="2014-07-02T20:09:14.150" Score="8" Body="&lt;p&gt;Yes, &lt;a href=&quot;http://www.spc.noaa.gov/exper/soundings/&quot;&gt;NOAA's Storm Prediction Center's soundings page&lt;/a&gt; is a great source for the information you are looking for, especially the skew-T diagrams and wind hodographs. This site provides current soundings as well as a past archive of 1 week. For the explanation of the soundings diagrams and numbers provided, see the &lt;a href=&quot;http://www.spc.noaa.gov/exper/soundings/help/index.html&quot;&gt;soundings help page&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2014-07-03T15:06:52.907" LastActivityDate="2014-07-03T15:06:52.907" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2212" PostTypeId="2" ParentId="2164" CreationDate="2014-07-02T22:51:39.393" Score="6" Body="&lt;p&gt;The Earth's climate switches between &quot;hothouse Earth&quot;, where ice is nearly absent worldwide, and &quot;icehouse Earth&quot; where the Earth intermittently has ice that stretches far from the poles. Periods when the Earth is in the icehouse Earth phase are called ice ages. The most recent ice age began about 2.6 million years ago and has not yet ended. We are still in an ice age, as evidenced by the fact that Antarctica and Greenland are still covered by ice. Ice ages last many tens to a few hundred of millions of years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ice ages are characterized by glacial periods where ice reaches far from the poles separated by interglacial periods where the climate is a bit more moderate. The glacial and interglacial periods within an ice age last tens to hundreds of thousands of years. The current interglacial period began about 12,000 years ago.  It's the Milankovitch cycles that are responsible for the short duration glacial and interglacial periods within an ice age.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These cycles are still present when the Earth is in a hothouse Earth phase. The Earth was in the hothouse phase for about 250-260 million years before the current ice age. That's 2000 or so multiples of the very longest Milankovitch cycle. The Milankovitch cycles are not responsible for the hothouse Earth / icehouse Earth phases. It's plate tectonics that dictates whether Earth is in a hothouse Earth or icehouse Earth phase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what aspects of plate tectonics govern whether the Earth is in a hothouse phase or icehouse phase? Below are a series of images depicting how the Earth looked over recent times.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://upload.wikimedia.org/wikipedia/commons/thumb/7/73/Blakey_35moll.jpg/640px-Blakey_35moll.jpg&quot; rel=&quot;noreferrer&quot;&gt;http://upload.wikimedia.org/wikipedia/commons/thumb/7/73/Blakey_35moll.jpg/640px-Blakey_35moll.jpg&lt;/a&gt;&lt;br&gt;&#xA;35 million years ago, hardly any ice anywhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://upload.wikimedia.org/wikipedia/commons/thumb/2/2c/Blakey_20moll.jpg/640px-Blakey_20moll.jpg&quot; rel=&quot;noreferrer&quot;&gt;http://upload.wikimedia.org/wikipedia/commons/thumb/2/2c/Blakey_20moll.jpg/640px-Blakey_20moll.jpg&lt;/a&gt;&lt;br&gt;&#xA;20 million years ago, just a tiny bit of ice in the very far north and very far south.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://upload.wikimedia.org/wikipedia/commons/thumb/7/7e/Blakey_Pleistmoll.jpg/640px-Blakey_Pleistmoll.jpg&quot; rel=&quot;noreferrer&quot;&gt;http://upload.wikimedia.org/wikipedia/commons/thumb/7/7e/Blakey_Pleistmoll.jpg/640px-Blakey_Pleistmoll.jpg&lt;/a&gt;&#xA;Current ice age, (~2.6 million years ago to present), with ice sometimes reaching as far as 45° latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://cpgeosystems.com/paleomaps.html&quot; rel=&quot;noreferrer&quot;&gt;Ron Blakey&lt;/a&gt;, via wikimedia.org. (Blakey's maps are 1200x600, which is a bit wide. I used the 640x320 previews at wikimedia.org.)&#xA;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two key differences at the boundaries of the Pacific Ocean between the pre-ice age Earth and our current ice age Earth. One is the Indonesian seaway. That closed up 3 to 4 million years ago thanks to New Guinea, Indonesia, and the Malay Peninsula. The other is the Panama seaway. That closed up about 3 million years ago thanks to the formation of the Isthmus of Panama. The closing off of the Pacific near the equator drastically changed the global ocean conveyor belt, which in turn drastically changed the climate of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So which of these two seaway closures, if any, is the cause of the most recent switch from hothouse Earth to icehouse Earth? A number of researchers put the blame on the formation of the Isthmus of Panama (Bartoli 2005, Nie 2014). Others claim the closure of the Indonesian seaway was responsible (Cane and Molner 2001, Molner 2008). Yet others say &quot;none of the above&quot; (Lunt 2008). The jury is still out, but note that Smith and Pickering 2003 claim that plate tectonics are responsible for each of the four major icehouses in the last 620 million years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;&lt;a href=&quot;http://www.ldeo.columbia.edu/~polissar/teaching/F2012_G9600_Climate_Puzzles_of_the_Neogene/Bartoli_et_al_2005.pdf&quot; rel=&quot;noreferrer&quot;&gt;Bartoli, G., et al. (2005). &quot;Final closure of Panama and the onset of northern hemisphere glaciation.&quot; &lt;em&gt;Earth and Planetary Science Letters&lt;/em&gt;, 237.1: 33-44.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://cpgeosystems.com/paleomaps.html&quot; rel=&quot;noreferrer&quot;&gt;Blakey, Ron. cpgeosystems.com/paleomaps.html (website)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://water.columbia.edu/files/2011/11/Cane2001Closing.pdf&quot; rel=&quot;noreferrer&quot;&gt;Cane, Mark A., and Peter Molnar (2001). &quot;Closing of the Indonesian seaway as a precursor to east African aridification around 3–4 million years ago.&quot; &lt;em&gt;Nature&lt;/em&gt; 411.6834: 157-162.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/nature/journal/v454/n7208/full/nature07223.html&quot; rel=&quot;noreferrer&quot;&gt;Lunt, Daniel J., et al. (2008). &quot;Late Pliocene Greenland glaciation controlled by a decline in atmospheric CO2 levels.&quot; &lt;em&gt;Nature&lt;/em&gt; 454.7208: 1102-1105.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2007PA001574/full&quot; rel=&quot;noreferrer&quot;&gt;Molnar, Peter (2008). &quot;Closing of the Central American Seaway and the Ice Age: A critical review.&quot; &lt;em&gt;Paleoceanography&lt;/em&gt; 23.2.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/srep/2014/140627/srep05474/full/srep05474.html&quot; rel=&quot;noreferrer&quot;&gt;Nie, Junsheng, et al. (2014). &quot;Pacific freshening drives Pliocene cooling and Asian monsoon intensification.&quot; &lt;em&gt;Scientific Reports&lt;/em&gt; 4.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://jgs.lyellcollection.org/content/160/3/337.short&quot; rel=&quot;noreferrer&quot;&gt;Smith, Alan G., and Kevin T. Pickering (2003). &quot;Oceanic gateways as a critical factor to initiate icehouse Earth.&quot; &lt;em&gt;Journal of the Geological Society&lt;/em&gt; 160.3: 337-340.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2014-07-03T13:02:45.327" LastActivityDate="2014-07-03T13:02:45.327" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2213" PostTypeId="1" CreationDate="2014-07-03T07:31:26.703" Score="12" ViewCount="132" Body="&lt;p&gt;I wonder what the average ratio between aragonite and calcite is during the precipitation of biogenic calcium carbonate in seawater. I know some species are aragonite-favouring and some perfer using calcite. I also know that aragonite is about 50% more soluble than calcite, and therefore less common.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If any of you would know a (coarse) average between these two (with references if possible)? &lt;/p&gt;&#xA;" OwnerUserId="475" LastEditorDisplayName="user889" LastEditDate="2015-01-31T04:09:01.540" LastActivityDate="2015-01-31T04:09:01.540" Title="Average Aragonite:Calcite ratio in biogenic CaCO3 in the oceans" Tags="|ocean|oceanography|geobiology|carbonate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2214" PostTypeId="1" CreationDate="2014-07-03T18:03:54.837" Score="17" ViewCount="198" Body="&lt;p&gt;When studying sea level changes, it is normal to analyze water level with respect to a common vertical datum. The most used datum is Mean Sea Level (MSL), which NOAA defines as &lt;a href=&quot;http://tidesandcurrents.noaa.gov/datum_options.html&quot;&gt;&quot;The arithmetic mean of hourly heights observed over the National Tidal Datum Epoch&quot;&lt;/a&gt;. The issue is that MSL constantly changes, and therefore it needs to be referenced to a different datum. One option is to use an ellipsoid of the entire Earth (for instance WGS 84, like the GPS uses) but the differences with respect to MSL can be big (&gt;100m). The other option is to use a geoid datum. In the US, we normally use the North American Vertical Datum of 1988 (&lt;a href=&quot;http://www.ngs.noaa.gov/datums/vertical/VerticalDatums.shtml&quot;&gt;NAVD88&lt;/a&gt;), but that only covers the US, Canada and Mexico. What are the options for global geoids?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="11908" LastEditDate="2019-01-07T17:45:30.813" LastActivityDate="2019-01-07T17:45:30.813" Title="What is the appropriate vertical datum to use globally?" Tags="|ocean|oceanography|sea-level|gnss|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2215" PostTypeId="2" ParentId="2189" CreationDate="2014-07-04T00:40:20.633" Score="11" Body="&lt;p&gt;Not as far as I am aware. Any dating of the rock would determine the formation age of the rock (dating isn't quite as straight forward as that, and there is a whole science behind what each dating technique actually determines but for simplicity's sake we say it is the formation date) but the fracture plane,where the hand sample has broken away from the source rock, would not provide any distinct geochemical signatures that are different to the rest of the hand sample.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only possible way you could very roughly estimate the age would be to compare the amount of mineral weathering on the fracture plane to that of the rest of the hand sample. Such minerals as K-feldspars weather to clays and comparing the amounts of clays of the fracture plane to else where on the sample you might be able to determine the relative age of the fracture plane (note: relative age is not the same as absolute age (&lt;a href=&quot;http://en.wikipedia.org/wiki/Absolute_dating&quot; rel=&quot;noreferrer&quot;&gt;http://en.wikipedia.org/wiki/Absolute_dating&lt;/a&gt;)), taking in to account the average rate of chemical weathering of the mineral, the amount of rain fall and other environmental conditions of the area that the sample was taken from. A possible way around this problem is if the outcrop that the sample was taken from had extensive fracturing you maybe able to find some fracture planes that contained mineral in-fill and dating those minerals you might be able to determine the age of the fractures. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This paper &lt;a href=&quot;http://www.terrapub.co.jp/journals/GJ/pdf/4103/41030165.pdf&quot; rel=&quot;noreferrer&quot;&gt;http://www.terrapub.co.jp/journals/GJ/pdf/4103/41030165.pdf&lt;/a&gt; outlines an attempt to date these minerals and also details some of the downfalls of the technique. But as I stated first of all, there is no technique I am aware of that will allow you to date the age the a piece of float became a piece of float.&lt;/p&gt;&#xA;" OwnerUserId="645" LastEditorUserId="645" LastEditDate="2014-07-04T08:28:36.730" LastActivityDate="2014-07-04T08:28:36.730" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2216" PostTypeId="2" ParentId="334" CreationDate="2014-07-04T01:58:39.243" Score="10" Body="&lt;p&gt;After some brief research, &lt;a href=&quot;https://web.archive.org/web/20131005020608/http://earth.huji.ac.il/data/pics/Nuriel%20et%20al%202009.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;serpentinite diapirism occurs due to deep penetration of seawater at temperature around 100-200&lt;span class=&quot;math-container&quot;&gt;$^o$&lt;/span&gt;C&lt;/a&gt;. To the south of the rift that was forming the ophiolite sequence there was an oceanic plate subducting as African plate moved north. This subducting oceanic plate provided the seawater that serpentinized the harzburgite in the ophiolite sequence. From my understanding this removed the water from the system before it reached depths to form partial melt. The subducting plate also assisted in pushing the diapir to the surface through the detachment faults present from the rifting.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ssYOF.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ssYOF.jpg&quot; alt=&quot;tectonic evolution&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;sub&gt;(source: &lt;a href=&quot;http://www.moa.gov.cy/moa/gsd/gsd.nsf/f6b12283222a96a3c225734000315725/a9e0eeb1c9dc2e5ec225734000329c12/MainText/0.8A?OpenElement&amp;amp;FieldElemFormat=jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;moa.gov.cy&lt;/a&gt;)&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="645" LastEditorUserId="2958" LastEditDate="2023-01-04T00:27:25.880" LastActivityDate="2023-01-04T00:27:25.880" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="2217" PostTypeId="2" ParentId="996" CreationDate="2014-07-04T04:58:29.080" Score="8" Body="&lt;p&gt;A basic and oversimplified answer would be that Earth has the right amount of heat, both to begin with and a continued supply from radioactive elements. Venus has too much (surface temp. is around 750 K) and therefore the planet doesn't have the same stratification (i.e. cold-hard crust, mantle, core) as Earth. Mars on the other hand it too cold. It doesn't have the same size as Earth resulting in less thermal energy which is the driving force behind plate tectonics. This lack of heat results in very little force trying to move the crust around.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer to what makes Earth so special is really it has the 'right' amount of heat. Keeping in mind that the 'goal' is to get rid of the heat and plate tectonics and all that it entails (e.g. mantle plumes, mid-ocean rifts, volcanoes) are ways to release that heat from the Earth. Eventually all these mechanisms will slow down and stop and Earth will be in a similar state to Mars.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for your main question, I am no physicist, but I would speculate that formation by acceration would be required so that the body was stratified into some form of cold-hard crust, mantle, and core, and there would be some minimum limits on the size of the body (possible maximum limits but I have no idea about that) because anything too small would solidify pretty quickly (or just become a blob of molten magma, would depend on how hot it was and what kind of environment it was in i.e. has an atmosphere or no atmosphere). But as I previously stated the key factors would be the right amount of initial heat (from the accreation of the body) and the correct amount of insulation. Too much of both and you get Venus, too little Mars. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a side point &lt;a href=&quot;http://www3.imperial.ac.uk/earthscienceandengineering/research/iarc/theplanets/platetectonicsonvenus&quot;&gt;this article&lt;/a&gt; makes the good point that it does depend on what you define as plate tectonics and what we have on Earth may not be the norm...  And who knows Venus might have cooled down enough in a few hundred million years that it present Earth-like plate tectonics.&lt;/p&gt;&#xA;" OwnerUserId="645" LastEditorUserId="645" LastEditDate="2014-07-04T05:24:08.633" LastActivityDate="2014-07-04T05:24:08.633" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2218" PostTypeId="2" ParentId="977" CreationDate="2014-07-04T06:51:01.533" Score="4" Body="&lt;p&gt;Seasons are determined by the degree of tilt of the planet's axis, not the mass of the atmosphere.  Mars has an axial tilt slightly larger than Earth, so Mars' seasons are slightly more pronounced than Earth's.  For a planet like Venus, which has virtually no rotation and an extreme axial tilt, &quot;seasons&quot; are also affected by the rotation/revolution ratio.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are interested in the climate differences between separate planets, mass of the atmosphere does affect overall global temperature (e.g. more atmospheric mass = more heat trapping) but the mass itself is not the main driver of the dynamic changes of climate within an individual atmosphere.  Really Mars and Venus don't have as much &quot;short term&quot; climate dynamics like Earth, because they don't have ocean/land dynamics.  Though, they definitely have seasons. Earth's &quot;short term&quot; climate dynamics are driven by the heterogeneous distribution of land, ocean, and (to a smaller extent) clouds.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;All the planets do share similar long term drivers of climate dynamics, which on Earth are collectively known as the Malenkovitch cycles.  The Malenkovich cycles are on the order of 10s of thousands of years and include changes in axial tilt, axial precession, and orbital eccentricity.  Some would also argue that long term gravitational changes in orbit parameters due to trojan asteroids and large planets like Jupiter also affect the Malenkovitch cycles.  These cycles shift the timing, intensity, and spatial distribution of solar input to the planet. &lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2014-07-04T06:51:01.533" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2219" PostTypeId="1" AcceptedAnswerId="2243" CreationDate="2014-07-04T07:01:43.157" Score="21" ViewCount="859" Body="&lt;p&gt;An uneducated layman like me would just look at &lt;a href=&quot;https://en.wikipedia.org/wiki/Convective_available_potential_energy&quot;&gt;CAPE&lt;/a&gt; numbers and make rough guesses on possible thunderstorms. In a related but non-duplicate &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2210/is-there-a-convenient-place-to-get-vertical-wind-shear-info-for-my-location&quot;&gt;question&lt;/a&gt;, vertical wind shear is discussed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we are talking about predicting afternoon thunderstorms at or near a single location (&lt;strong&gt;8 hours ahead&lt;/strong&gt;), what are the rules of thumb that skilled meteorologists follow to estimate the likelihood of the condition based on three possible sets of data:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;when they have no more data on their hands than those produced by mesoscale models like &lt;a href=&quot;https://en.wikipedia.org/wiki/Weather_Research_and_Forecasting_model&quot;&gt;WRF&lt;/a&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;when a &lt;a href=&quot;https://en.wikipedia.org/wiki/Rawinsonde&quot;&gt;radiosonde&lt;/a&gt; is launched in early morning.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;when a weather radar is added to the mix.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Background&lt;/strong&gt;: I am curious about actual procedures/decision templates used at various &lt;a href=&quot;https://en.wikipedia.org/wiki/Eastern_Test_Range&quot;&gt;rocket launch sites&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="269" LastEditorUserId="269" LastEditDate="2014-07-04T19:44:22.177" LastActivityDate="2014-07-11T08:37:07.920" Title="What data does a skilled meteorologist look at to predict thunderstorms?" Tags="|meteorology|weather-forecasting|thunderstorm|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2220" PostTypeId="2" ParentId="2189" CreationDate="2014-07-04T14:36:10.380" Score="18" Body="&lt;p&gt;There is a technique called &lt;a href=&quot;http://en.wikipedia.org/wiki/Surface_exposure_dating&quot;&gt;&quot;Exposure Dating&quot;&lt;/a&gt;. Using e.g. cosmogenic nuclides (they are produced in the first metre or so of the surface of a rock which is exposed to cosmic rays, i.e. on the surface of the earth), it is possible to estimate the amount of time that the rock was exposed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With some assumptions, you can get an exposure age of the fracture surface (or at least some information about it) since the fracture surface was exposed to cosmic rays only recently, whereas the rest of the surface was exposed to it long before.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The specific sample is probably too small though. This technique is useful to date the retreat of glaciers (they shield cosmic rays from the underlying bedrock), fault scarps, or the time a meteorite spent flying in space from its parent body to the earth.&lt;/p&gt;&#xA;" OwnerUserId="646" LastEditorUserId="646" LastEditDate="2014-07-04T14:41:16.860" LastActivityDate="2014-07-04T14:41:16.860" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2221" PostTypeId="2" ParentId="194" CreationDate="2014-07-04T17:21:43.720" Score="5" Body="&lt;p&gt;HIRS is an old NASA heritage design that flew on both European and US weather satellites as part of the EUMETSAT/NOAA Initial Joint Polar System.  The Inrared Atmospheric Sounding Interferometer (IASI) will take over the duties of HIRS, since IASI is a more powerful instrument with European design for a European satellite.  You can see this discussed here: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.esa.int/Our_Activities/Observing_the_Earth/The_Living_Planet_Programme/Meteorological_missions/MetOp/About_HIRS_4/%28print%29&quot; rel=&quot;noreferrer&quot;&gt;http://www.esa.int/Our_Activities/Observing_the_Earth/The_Living_Planet_Programme/Meteorological_missions/MetOp/About_HIRS_4/(print)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My perspective on this is that historically the US was the international leader in environmental satellites.  The Europeans now have better designs and more committed plans to environmental satellites over the next couple decades.  So, essentially, they don't need our out-dated hardware anymore.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2014-07-04T17:21:43.720" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2222" PostTypeId="1" CreationDate="2014-07-04T20:00:21.500" Score="9" ViewCount="82" Body="&lt;p&gt;Has the relative ratio of sedimentary over igneous rocks increased, simply as a result of more and more of the Earth's rock being exposed to sedimentary processes?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or has it increased only for the first billion years of Earth's history, and stayed fairly constant afterwards?&lt;/p&gt;&#xA;" OwnerUserId="10" LastActivityDate="2014-07-04T20:00:21.500" Title="How has the relative ratio of igneous, sedimentary, and metamorphic rocks changed over Earth's history?" Tags="|geology|" AnswerCount="0" CommentCount="0" ClosedDate="2014-12-04T03:44:00.927" ContentLicense="CC BY-SA 3.0" />
  <row Id="2223" PostTypeId="1" CreationDate="2014-07-05T04:03:47.110" Score="7" ViewCount="510" Body="&lt;p&gt;The &lt;a href=&quot;http://www.skepticalscience.com/Why-does-CO2-lag-temperature.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;explanation&lt;/a&gt; given for the fact that temperature has historically led CO₂ levels is &lt;a href=&quot;http://en.wikipedia.org/wiki/Henry%27s_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Henry's law&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/aG30w.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Figure 1: Vostok ice core records for carbon dioxide concentration (Petit 2000) and temperature change (Barnola 2003), posted on www.skepticalscience.com.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, no statistical evidence for the other Henry's law variables are ever supplied.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the historical Henry's law variables?&lt;/p&gt;&#xA;" OwnerDisplayName="user641" LastEditorUserId="725" LastEditorDisplayName="user641" LastEditDate="2014-12-09T05:51:08.227" LastActivityDate="2014-12-09T05:52:37.237" Title="Historical atmospheric partial pressure &amp; Henry's law constant" Tags="|earth-history|paleoclimatology|statistics|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2224" PostTypeId="2" ParentId="2223" CreationDate="2014-07-05T15:37:24.783" Score="5" Body="&lt;p&gt;The source you mentioned tries to explain why CO&lt;sub&gt;2&lt;/sub&gt; lags by about 1000 years in historical records. &#xA;Henry's law tells you something about the equilibrium between the CO&lt;sub&gt;2&lt;/sub&gt; level in the surface layer and the atmosphere. However, this is not the reason for the 1000 year time-lag mentioned. There's not enough CO&lt;sub&gt;2&lt;/sub&gt; in the surface layer to cause these increases in atmospheric concentration. What is important is the exchange of CO&lt;sub&gt;2&lt;/sub&gt; between the deep sea and the surface layer. This seems to have a typical timespan of 1000 a.&#xA;Citing from your source:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;As the Southern Ocean warms, the solubility of CO&lt;sub&gt;2&lt;/sub&gt; in water falls (Martin 2005). This causes the oceans to give up more CO&lt;sub&gt;2&lt;/sub&gt;, emitting it into the atmosphere. The exact mechanism of how the deep ocean gives up its CO&lt;sub&gt;2&lt;/sub&gt; is not fully understood but believed to be related to vertical ocean mixing (Toggweiler 1999). The process takes around 800 to 1000 years, so CO&lt;sub&gt;2&lt;/sub&gt; levels are observed to rise around 1000 years after the initial warming (Monnin 2001, Mudelsee 2001).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So the initial increase in CO&lt;sub&gt;2&lt;/sub&gt; levels due to Henry's law trigger via feedback mechanisms changes in the vertical circulation pattern thereby transporting more CO&lt;sub&gt;2&lt;/sub&gt; from the deep sea to the surface. It's this time constant that is seen in the records.&lt;/p&gt;&#xA;" OwnerUserId="526" LastEditorUserId="725" LastEditDate="2014-12-09T05:52:37.237" LastActivityDate="2014-12-09T05:52:37.237" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2225" PostTypeId="1" CreationDate="2014-07-05T20:28:37.803" Score="10" ViewCount="865" Body="&lt;p&gt;I'm interested in this problem because I'm interested in obtaining a rough estimate of the average temperature increase of the sea given a net radiative forcing of 0.6 W/m^2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But in order to obtain an estimate, I need to know the volume of the ocean between 0-2000m. I'm also interested in knowing the volume of the ocean between any other two arbitrary layers of the ocean (0-1000m, 1000-2000m, 0-4000m, etc..)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/wvAA8.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="10" LastEditorUserId="111" LastEditDate="2015-03-20T14:30:20.250" LastActivityDate="2015-03-20T14:30:20.250" Title="How do I find the volume of ocean between any two layers of ocean depth?" Tags="|ocean|bathymetry|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2226" PostTypeId="1" AcceptedAnswerId="2244" CreationDate="2014-07-06T02:11:20.333" Score="22" ViewCount="958" Body="&lt;p&gt;I've seen models in astronomy that show how the Earth-Moon system must have come together after a collision.  However, I have not heard whether there is any actual physical evidence on Earth that points to a prior collision.  Is there geological (or other physical) evidence here on Earth that confirms the moon originated from a collision on Earth?  If so what is that evidence?&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2014-11-22T04:39:30.873" LastActivityDate="2023-07-26T02:53:26.230" Title="Is there geological evidence that the moon once collided with the Earth?" Tags="|geology|planetary-science|moon|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2227" PostTypeId="1" CreationDate="2014-07-06T07:07:30.363" Score="12" ViewCount="583" Body="&lt;p&gt;In one of his presentations, Sandy MacDonald (of NOAA and ESRL) talks about the Rossby Radius of Deformation in connection with the size of synoptic weather systems: he describes how it sets the diameter of &quot;large-scale&quot; systems to be 1000-2000 km across, so that if we want to even out meteorological effects, we need to consider areas with diameter larger than that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How is the Rossby Radius of Deformation used to determine that scale of 1000 - 2000 km?&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="64" LastEditDate="2014-07-11T20:38:50.547" LastActivityDate="2014-07-11T20:38:50.547" Title="How is the Rossby Radius used to determine that synoptic weather systems are 1000-2000km across?" Tags="|meteorology|synoptic|dynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2228" PostTypeId="2" ParentId="996" CreationDate="2014-07-06T13:13:56.753" Score="13" Body="&lt;p&gt;Plate tectonics appears to require multiple factors all arraigned in feedback loops.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The planet must be large enough that it's surface to volume ratios is low enough to trap enough heat from radioactive decay to power tectonic motion. Convection requires a minimal threshold of energy trapped in the material before that trapped energy causes mechanical motion. Planets smaller than earth radiate internal heat away to quickly because of their larger surface to volume ratios. Thus little convection and little tectonic motion.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The planet must have sufficient mass such that it's escape velocity exceeds that of a hydrogen ion ejected from a water molecule via UV hydrolysis. If the planet does have sufficient mass, then the hydrogen release by UV hydrolysis will be recaptured. If not, the hydrogen will escape the planet and its orbit and the planet will eventually desiccate. Earth has enough mass to retain hydrogen, Mars and Venus do not. In the past, Mars had water but it leaked hydrogen over the eons until it became a desert. Venus likely suffered the same fate. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Oxygen producing life: Even with sufficient mass to trap hydrogen, a planet will still leak free hydrogen from having the hydrogen rise to the top of the atmosphere and there being knocked off by the solar wind. Free oxygen prevents this by a) forming ozone thus blocking the UV that breaks down water molecules and b) recombining with the free hydrogen that does form to produce water again. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The presence of large amounts of water produce hydrated minerals which, on the size and time scales of tectonic motion, behave more like a deformable putty than solid rock. These deformable minerals allow tectonic motion. Without them, tectonic forces would cause shattering instead of drift. (See: &lt;a href=&quot;https://physics.stackexchange.com/questions/48318/plate-tectonics-and-water&quot;&gt;Plate Tectonics and Water&lt;/a&gt;, and, &lt;a href=&quot;http://www.ens-lyon.fr/DSM/SDMsite/M2/stages_M2/Bouffard2013.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Role of water in the tectonics of Earth and Venus&lt;/a&gt;.)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Tectonic subduction recycles carbon trapped in carbonates by chemical weathering and organisms in the ocean. Subduction draws the carbonates down to the lower crust where they are &quot;cooked&quot; and the carbon converted to $\mathrm{CO}_2$ and $\mathrm{CH}_3$ which are returned to the biosphere via vulcanism. Without this recycling, all the carbon in the biosphere would end up as limestone on the ocean floor. Starved of carbon, all life would perish. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;It appears that the Earth has a much thinner and much more heterogeneous crust than either Mars or Venus. Likely, this is a result of the collision that produced the moon. The thinner crust is easier for geothermal convection to move. Also, it's possible that the collision &quot;stirred&quot; the distribution of heat producing radioisotopes leaving more near to the top of the mantel.  On Venus and Mars, it is likely that the very heavy radio isotopes sank to the core. This would make the upper mantel on Earth hotter than the other planet and hotter than it would have been without the collision. That would drive convection faster. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Likely, the critical difference for Earth was the collision that formed the moon. That both &quot;stirred the pot&quot; and added more mass. Earth retains both heat and hydrogen. Retaining hydrogen means retaining water which means life and hydrated minerals. Life produces oxygen that protects the water. Hydrated minerals provide the elasticity needed for tectonic motion. Tectonic motion recycles carbon needed for life. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take away anyone of these factors and a planets tectonic motion will eventually wind down in less than a billion years. &lt;/p&gt;&#xA;" OwnerUserId="652" LastEditorUserId="-1" LastEditDate="2017-04-13T12:40:15.470" LastActivityDate="2014-10-20T10:42:27.080" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2229" PostTypeId="2" ParentId="2185" CreationDate="2014-07-06T15:18:10.957" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is there a clear guideline as to what exactly constitutes a bad oil spill?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No, &quot;bad&quot; has no legal definition in any jurisdiction in North America. As a practical matter you can only establish regulations and enforce legal penalties, regulatory, civil or criminal by some sort of numerical, measurement based criteria.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How much oil must be spilled? &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;All material economic activity has some sort of negative tradeoff, all jurisdictions have some level of permissible harm. Each jurisdiction a pipeline passes through will have some level of oil leakage or other types of environmental harm that are permitted without triggering as legal consequence for the operator. However, this does not define &quot;bad&quot; but merely the trigger threshold.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An international pipeline like the Enbridge pipeline that crosses countries, provinces, states etc will be subject to a different set of rules for every jurisdiction and at times combinations of jurisdictions. You'd have to check each individual jurisdiction to find the threshold for each one. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is it dependent on what type of oil is spilled...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Usually, yes. Since the primary harm from oil is mechanical, the viscosity of oil is the prime predictor of the harm it will cause if spilled. Crude oil varies in viscosity from a thin syrup to thick paste. The former can spread fairly far in warm weather while the later usually just piles up at the leak. The former causes more harm per unit of escaped volume than the later. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of the oil moved in the Enbridge is dilbit a diluted form of bitumen/asphalt from the tar sands. Bitumen/asphalt is arguably a solid so it has to be diluted with something else to make it a pumpable liquid. Depending on the viscosity chosen, the spread and mechanical risk will vary as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The diluent itself is going to be something volatile which could in principle constitute a greater toxicity danger than simple crude oil. Naphtha has been used in the past which is the most volatile fraction of any crude oil. Depending on the actual ratio, spilled dilbit will present a greater or lessor danger than a comparable (usually light) crude. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;and in what area,&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Quite definitely.  As noted above, the oil does not spread to any significant degree without water transport. A pipeline crossing a body of water or running near one will require more rigorous construction and closer monitoring than one that does not. Oil pipelines crossing desert or arid regions cause much less harm be unit of leaked volume than do pipelines in swamps or under body of water.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;populated by what species?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Usually, but again, this varies considerably depending on jurisdiction. &lt;/p&gt;&#xA;" OwnerUserId="652" LastEditorUserId="20" LastEditDate="2014-07-07T16:56:14.850" LastActivityDate="2014-07-07T16:56:14.850" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2230" PostTypeId="1" AcceptedAnswerId="2315" CreationDate="2014-07-06T16:23:23.217" Score="8" ViewCount="371" Body="&lt;p&gt;In 2010, Purdue University published a research paper[1] stating that their researchers had detected slight fluctuations in radioactive isotope decay rates &quot;in synch with the rotation of the sun's core.&quot; The article also stated:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The team has not yet examined isotopes used in medical radiation treatments or for dating of ancient artifacts.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Has there been any further research on this, and has it been found to affect carbon dating techniques or other archeological dating methods? Are the fluctuations large enough to call into question currently accepted geological dates?&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.purdue.edu/newsroom/research/2010/100830FischbachJenkinsDec.html&quot;&gt;http://www.purdue.edu/newsroom/research/2010/100830FischbachJenkinsDec.html&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="653" LastActivityDate="2014-08-07T12:42:18.603" Title="Do fluctuations in radioactive isotope decay rates affect carbon dating techniques?" Tags="|radioactivity|archaeology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2231" PostTypeId="2" ParentId="986" CreationDate="2014-07-06T16:57:14.953" Score="1" Body="&lt;p&gt;There doesn't seem to be a consensus model. All the 5 major models disagree on the specifics the last time I looked. Nobody has made more than general predictions as to the specifics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are general patterns based on the type of climate change and its primary driving cause.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Simplistically:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-) Warming change: Makes almost everywhere wetter. Higher overall temperatures allow the atmosphere to hold more water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-) Warming from non-water Greenhouse gasses: Effects strongest in the driest regions as greenhouses gasses like CO2 and CH4 provide greenhouse effect in place of water vapor. Polar latitudes most strongly affected as unlike deserts in lower latitudes, they usually have enough air circulation to bring in water, if the overall air temp rises high enough to transport the water. Decrease in temperature and humidity differentials between tropics and polar regions causes decrease in wind force and storm intensity. In most models, huge swaths of northern Alaska, Canada and Siberia will become wet and temperate. Something like the north Western coast of North America (Oregon to B.C.) Lots of soaking rain but few storms. I've seen it nicknamed the &quot;Great Soggy&quot; model.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;-) Warming solar: Effects most significant first in the tropical regions because the regions more consistent solar exposure. Initially at least, higher temperature differentials and more violent storms but those will decrease as the poles warm but likely poles will still have a relative lack of greenhouse warming from water vapor so temperatures will never equalize to the degree in the Greenhouse gas driven warming. Still more rain overall that current period used as a baseline combined with more violent weather. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;-) End of ice age: Likely, decrease in storm activity (the tropics don't cool at the same rate as the poles do during ice ages, so big storms) overall increase in perception. It is uncertain how ice ages affect non-water greenhouses gasses. On one hand, massive expanding biomass will suck huge amounts of CO2 out the atmosphere, on the other hand decaying biomass and possible exposure and subsequent biodegradation of ice interred biomass will cause net release of methane (CH4) whose greenhouse effect is 100 times that CO2. Depending on how that all balances out, the poles will get wetter or dryer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-) Cooling change: Makes everything dryer. Overall temperature change makes the atmosphere hold less water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;-) Start of ice age: Overall decreased precipitation with overall decrease in air temp and humidity. Increase in temp differential between tropics and poles caused by increased albedo from spreading perma-snow and then ice sheets. As biomass dies from cold, there will be some increase in CO2 meth &lt;/p&gt;&#xA;&#xA;&lt;p&gt;-) Greenhouse gasses driven cooling: In principle, to rapid warming can cause ice melting from land masses in the arctic which can shutdown the oceanic conveyer which is the massive world circling ocean current that moves at least 50% of the heat around the earth. If the conveyer shuts down, the poles will get suddenly cooler and dryer and the tropics will likely not get hotter and wetter but will expand into a wider latitude north and south. Temperature differentials will increase while at the same time the distance will decrease. This will drive massive storms. However, likely to be short lived. Conveyer will reactivate in a decade or so at most. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;-) Solar cooling: Somewhat the reverse of last. Overall dryer as the water holding of the total atmosphere decreases. Dry polar regions expand, wet tropics shrink. Increase in wind speeds but overall decrease in precipitation. Dying biomass will provide greenhouse gases but scale of offset unknown. Increase in storm activity relative to current base line. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of all the forms of climate change, greenhouse driven warming is the best scenario as the effects will be the least intense and will likely last no more than a century. Increasing rain fall and expansion of the temperate band will bring many benefits to Alaska, Canada and Russia. Increase in rainfall offset by decrease in wind speeds and storm violence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The start of the next Ice Age would be the worst case scenario. Droughts mixed with high winds and violent dry storms followed by longer and longer winters cumulating in permanent snow followed by kilometer thick glaciers that scrap everything down to the bedrock. &lt;/p&gt;&#xA;" OwnerUserId="652" LastActivityDate="2014-07-06T16:57:14.953" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2232" PostTypeId="1" CreationDate="2014-07-06T17:19:16.507" Score="12" ViewCount="1849" Body="&lt;p&gt;I am curious what mountains would look like if erosion occurred almost entirely by wind. Specifically, I am curious of how &lt;strong&gt;&lt;em&gt;granite&lt;/em&gt;&lt;/strong&gt; mountains would look on a &quot;snowball&quot; terrestrial-sized xenoplanet. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;On a &quot;snowball&quot; world, the planet is earth sized and retains water but it lies outside its sun's &quot;goldilocks zone&quot; and is to cold for liquid water. Ocean's freeze over to a deep of several kilometers with only deep pockets kept liquid by concentrated minerals and vulcanism. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With no liquid water there will be no liquid erosion and no ice fracturing. The only moisture at all in the air will come from sublimation so very little ice will be deposited at altitude and it likely won't form glaciers or otherwise contribute to erosion. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At lower altitudes, very slow moving glaciers will probably perform most erosion but at altitude it will be erosion from wind carrying water and CO2 crystals as an abrasive. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;On Earth, erosion from water causes convex (wide rock, narrow erosion channel) while glaciers causes concave (narrow rock, wide erosion channel.) Hard brittle rock such as granite suffers ice fracturing leaving a jagged vertical channels with overall angular features. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In dry areas on Earth erosion creates rounded, fluid structures like stones shaped by a stream. But I am unclear of how much that is a feature of wind erosion and how much a feature of softer sedimentary stones. It looks like Mars, where erosion is primarily wind driven, does have more rounded and less jagged mountains than on Earth but I don't know about the suspected composition of the those mountains. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If granite wears from the wind, does it round off or does it's internal structure cause it to fracture even without water? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thinking about it another way, if the Earth completely froze over, what would the Rockies, Andes or Himalayas look like after a few million years of wind only erosion?&lt;/p&gt;&#xA;" OwnerUserId="652" LastEditorUserId="662" LastEditDate="2014-07-10T15:01:33.880" LastActivityDate="2016-06-18T00:57:50.683" Title="Geomorphology of Mountains With Wind only Erosion" Tags="|planetary-science|geomorphology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2233" PostTypeId="2" ParentId="2213" CreationDate="2014-07-07T07:21:06.747" Score="5" Body="&lt;p&gt;After some more research, the conclusion is that aragonite is somewhere between 10 and 50% of total CaCO&lt;sub&gt;3&lt;/sub&gt; production:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Aragonite, calcite-Mg and calcite are the 3 main species of marine CaCO&lt;sub&gt;3&lt;/sub&gt;. Aragonite is unlikely to be a major component of the total CaCO&lt;sub&gt;3&lt;/sub&gt; flux (Berelson, 2007), though the exact contribution is uncertain and falls in the range of 10-50% of global CaCO&lt;sub&gt;3&lt;/sub&gt; production (Gangstø, 2008). Minimum values of 12% (Berner and Honjo, 1981) and 13% (Fabry and Deuser, 1992) have been reported based on sediment traps. Calcite-Mg contributes ~8% (Fabry and Deuser, 1992) to 24% (Morse, 2006) to CaCO&lt;sub&gt;3&lt;/sub&gt; production. The sediment trap-based contribution of aragonite of ~12% is thought to be lower than the actual contribution of aragonite to CaCO&lt;sub&gt;3&lt;/sub&gt; production because aragonite is about 1.5 times more soluble than calcite and therefore more depleted than calcite in the sediment trap records.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An educated guess of me would therefore be ~20% aragonite, ~10% calcite-Mg and ~70% calcite globally on average.&lt;/p&gt;&#xA;" OwnerUserId="475" LastEditorUserId="725" LastEditDate="2014-12-09T05:48:47.263" LastActivityDate="2014-12-09T05:48:47.263" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2234" PostTypeId="1" CreationDate="2014-07-07T07:31:20.570" Score="9" ViewCount="66" Body="&lt;p&gt;When examining the potential for large-scale electricity grids, and when identifying the lowest-cost ways to generate clean electricity, a recurring theme is of spreading wind generation across a wide-enough area that it evens out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One way to bring down costs a lot, is to combine on the same grid, regions where the wind over a period of weeks to years, are negatively correlated: that is to say, it helps if we can easily identify pairs of regions where low winds in one region tend to happen at the same time as high winds in the other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At a scale of days, sufficiently distant regions are uncorrelated. At a scale of weeks to years, a set of correlations of reanalysis data (e.g. ECMWF or CFSR) suggests that there are pairs of regions which do exhibit negatively correlated wind, either seasonally or annually.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a reliable way to identify such combinations of regions?&lt;/p&gt;&#xA;" OwnerUserId="100" LastActivityDate="2014-07-07T14:35:44.647" Title="Is there a reliable way to identify regions with negatively-correlated winds?" Tags="|meteorology|wind|synoptic|correlation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2235" PostTypeId="2" ParentId="2225" CreationDate="2014-07-07T07:32:35.390" Score="7" Body="&lt;p&gt;You can find gridded topography and bathymetry data, freely accessible, on the website of the NOAA. For instance you have the ETOPO1 dataset &lt;a href=&quot;http://www.ngdc.noaa.gov/mgg/global/global.html&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once you downloaded it you can work it out with your favourite GIS software or GIS-supporting programming language.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The equations to calculate the volume based on the gridded cells is given on &lt;a href=&quot;http://www.ngdc.noaa.gov/mgg/global/etopo1_ocean_volumes.html&quot;&gt;this page&lt;/a&gt; from the NGDC website.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Volume Calculation &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Volumes were calculated for each ocean grid cell in ETOPO1 using&#xA;  Equation 1 to determine cell area, and Equation 2 to determine cell&#xA;  volume. Cell areas and volumes were then summed over each ocean or&#xA;  marginal sea.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Equation 1: $dA = \frac{a^2\cdot cos(ø)\cdot (1-e^2)\cdot dø\cdot dl}{(1-e^2 \cdot sin^2ø)^2}$&lt;br&gt;&#xA;  Equation 2: $dV = dA \cdot depth$&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;where:&lt;br&gt;&#xA;  Latitude (ø)  = latitude of cell's center (in radians)&lt;br&gt;&#xA;  Unit of Latitude (dø) = 1 arc-minute ($2.908882 \cdot 10^{-4}$ radians)&lt;br&gt;&#xA;  Unit of Longitude (dl)    = 1 arc-minute ($2.908882 \cdot 10^{-4}$ radians)  &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The WGS84 spheroid was used for values of Earth's radius and&#xA;  eccentricity:&lt;br&gt;&#xA;  Equatorial radius (a) = 6378.137 km&lt;br&gt;&#xA;  Eccentricity (e)  = 0.08181919&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="87" LastActivityDate="2014-07-07T07:32:35.390" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2236" PostTypeId="1" AcceptedAnswerId="2237" CreationDate="2014-07-07T12:46:18.073" Score="14" ViewCount="6320" Body="&lt;p&gt;Would sea level change at the equator if the Earth stopped spinning? I am assuming it is currently bulging around it due to centrifugal force.&lt;/p&gt;&#xA;" OwnerUserId="654" LastEditorUserId="56" LastEditDate="2014-09-18T05:59:29.913" LastActivityDate="2018-12-11T00:06:01.937" Title="Effect on sea level if the Earth stopped rotating" Tags="|ocean|sea-level|earth-rotation|hypothetical|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2237" PostTypeId="2" ParentId="2236" CreationDate="2014-07-07T14:23:00.390" Score="14" Body="&lt;p&gt;Let's assume that the earth didn't suddenly stop spinning (because intertia and conservation of angular momentum would do all sorts of &quot;interesting&quot; things that are deserving of a &lt;a href=&quot;http://what-if.xkcd.com/&quot; rel=&quot;nofollow&quot;&gt;What-If&lt;/a&gt; answer), and stipulate that the earth slowed down gradually, or possibly that it was never spinning in the first place (although I'm sure this would have all sorts of other effects that wouldn't have got us to where we are...)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, sea levels would change, but not necessarily for the reasons that you think.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Centrifugal force&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Part of the bulge in oceans is due to centrifugal force on the water, but much of it is not. There is an underlying bulge in the &lt;em&gt;seabed&lt;/em&gt; as well as the ocean. A result of this (and other variations in the thickness and density of the crust) are that the earth's gravitational field is not even across the globe, and where there is a stronger area of gravitational field, more water is pulled towards it and a bulge results. It is this effect that allows for the bathymetry of oceans to be mapped by satellites that sense the elevation of the sea's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am no geoscientist, but I imagine that this bulge in the crust at the equator is also to do with centrifugal force - but it would take a lot longer to go away, if indeed it did at all, than one caused just by water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDITING to add that there is now an answer elsewhere on this site re the bulge in the crust: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7707/how-viscous-is-the-earths-mantle&quot;&gt;How viscous is the Earth&amp;#39;s mantle?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Changes in tides &amp;amp; ocean currents&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;If the planet were not rotating, the dominant period for tidal cycles would likely  be related to a lunar month rather than to a day. There would also be no Coriolis effect, and these two factors would result in major differences to tides and to ocean circulations. As such, it is likely that there would be substantial differences in both short- and long-term elevation changes that are due to currents.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Other effects&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;I suspect that lack of rotation might have effects on the planet's core and its magnetic field, which might result in all sorts of other impacts... but we'll have to wait for a geoscientist in a speculative mood to talk about things like that :-)&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2016-05-27T14:11:40.680" LastActivityDate="2016-05-27T14:11:40.680" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2239" PostTypeId="2" ParentId="2234" CreationDate="2014-07-07T14:35:44.647" Score="6" Body="&lt;p&gt;My suggestion would be to do a Principal Component Analysis (&lt;a href=&quot;http://en.wikipedia.org/wiki/Principal_component_analysis&quot;&gt;PCA&lt;/a&gt;) or Empirical Orthogonal Functions (&lt;a href=&quot;https://climatedataguide.ucar.edu/climate-data-tools-and-analysis/empirical-orthogonal-function-eof-analysis-and-rotated-eof-analysis&quot;&gt;EOF&lt;/a&gt;) analysis on the wind data. The result of the analysis would be a set of modes of variability. You would be looking for modes that show areas that are large in magnitude but out of phase. As for the time scale, you need to check the eigenvectors and eigenvalues of the analysis to determine the scale of temporal variability.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can find appropriate code in many places, for instance &lt;a href=&quot;http://pmc.ucsc.edu/~dmk/notes/EOFs/EOFs.html&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-07-07T14:35:44.647" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2240" PostTypeId="1" AcceptedAnswerId="2245" CreationDate="2014-07-07T23:08:40.483" Score="14" ViewCount="21902" Body="&lt;p&gt;My geology textbook tells me that soil is not renewable, and I agree with this, but there was some question in my class as to whether this is true.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some soils take more than a human lifetime to regenerate.  However, in crop production, it seems as if soil can be regenerated with additives.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the scientific community of soil scientists, is soil considered a renewable resource by most of those scientists?  Is there strong evidence to support this?&lt;/p&gt;&#xA;" OwnerUserId="510" LastActivityDate="2016-09-13T16:34:17.167" Title="Is soil a renewable resource?" Tags="|resources|soil|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2241" PostTypeId="1" AcceptedAnswerId="2242" CreationDate="2014-07-08T13:30:06.650" Score="21" ViewCount="1620" Body="&lt;p&gt;A tornado has an effective area of destruction about the size of a city block.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/File:Dszpics1.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/k9LYm.jpg&quot; alt=&quot;Tornado&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A hurricane spans several hundred kilometers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/File:Hurricane_Isabel_from_ISS.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lOZ2j.jpg&quot; alt=&quot;Hurricane Isabel&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, there doesn't seem to be a continuum between the two.  Why are there no vortex windstorms on the scale of a city?  Is it because tornadoes and hurricanes have different formation mechanisms?  Or is there a reason why city-sized vortices would be so weak as to be un-newsworthy?&lt;/p&gt;&#xA;" OwnerUserId="431" LastEditorDisplayName="user12525" LastEditDate="2019-04-20T18:08:14.457" LastActivityDate="2024-03-20T23:43:27.273" Title="Why is there no middle ground between tornadoes and hurricanes?" Tags="|meteorology|wind|tropical-cyclone|storms|tornado|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2242" PostTypeId="2" ParentId="2241" CreationDate="2014-07-09T15:33:28.710" Score="27" Body="&lt;p&gt;Tornadoes are the result of small-scale effects such as the convergence of updraft/downdraft regions in a single thunderstorm, the stretching or entrainment of vertical vorticity, wind shear profiles, and even friction with the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hurricanes rely on massive amounts of latent heat release from an atmosphere moistened by warm ocean waters causing rising air and lower pressure over a wide area.  This allows the Coriolis effect to act, sculpting airflow into a spiral pattern.  Under normal conditions, the Coriolis effect is only applicable over a large area (don't get me started on the toilet myth).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are some intermediate types of circulations.  A mesocyclone is roughly city-sized (and these are often associated with tornadoes).  A mesoscale convective vortex can form out of a thunderstorm complex and are roughly state-sized (usually more of an Indiana than a Texas).  There have been very small hurricanes and typhoons (look up Tropical Storm Marco or Typhoon Tracy).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Extending the scale upward, the normal &quot;synoptic&quot; low pressure systems associated with cold and warm fronts and usually bigger than hurricanes, and upper-level circulations can be continent-sized.&lt;/p&gt;&#xA;" OwnerUserId="661" LastActivityDate="2014-07-09T15:33:28.710" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2243" PostTypeId="2" ParentId="2219" CreationDate="2014-07-09T19:42:51.923" Score="14" Body="&lt;p&gt;For same day forecasting of afternoon thunderstorms, I'd start with the morning observations and the 12Z&lt;sup&gt;†&lt;/sup&gt; model runs (I choose 12Z because that is the morning here in the Americas.  For Europe you might be more interested in the 00Z or 06Z runs to start your day).  In particular I'd start with the output of the 12Z &lt;a href=&quot;http://www.emc.ncep.noaa.gov/GFS/&quot; rel=&quot;noreferrer&quot;&gt;GFS&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/North_American_Mesoscale_Model&quot; rel=&quot;noreferrer&quot;&gt;NAM&lt;/a&gt;, and then give that some time to propagate into the &lt;a href=&quot;http://rapidrefresh.noaa.gov/&quot; rel=&quot;noreferrer&quot;&gt;RAP&lt;/a&gt; and finally the &lt;a href=&quot;http://ruc.noaa.gov/hrrr/&quot; rel=&quot;noreferrer&quot;&gt;HRRR&lt;/a&gt; models which are initialized from each other starting with GFS.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For observational data, I'm interested in the 12Z &lt;a href=&quot;https://en.wikipedia.org/wiki/Weather_balloon&quot; rel=&quot;noreferrer&quot;&gt;balloon&lt;/a&gt; launch, surface fields (temperature, dew point, winds, pressure), upper air data (850 mb temperature, 500 mb wind and vorticity, 300 mb wind) and satellite imagery (for cloud cover).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At 12Z the morning soundings are going often going to have the remnants of a nocturnal inversion and the previous days boundary layer.  Give cloud cover and surface temperature and moisture advection you can get a rough idea of how that boundary layer will evolve.  An hour or two after 12Z the GFS and NAM will start coming in and you can look at forecast soundings and how the model thinks things will evolve.  Around 15-17Z I'm looking at the HRRR for some additional guidance.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Convective_available_potential_energy&quot; rel=&quot;noreferrer&quot;&gt;CAPE&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Wind_shear&quot; rel=&quot;noreferrer&quot;&gt;wind shear&lt;/a&gt; only tell part of the story.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/mD1WR.png&quot; alt=&quot;CAPE vs Wind shear&quot;&gt;&#xA;Image credits: &lt;a href=&quot;https://commons.wikimedia.org/wiki/User:Pierre_cb&quot; rel=&quot;noreferrer&quot;&gt;Pierre_cb&lt;/a&gt; via &lt;a href=&quot;https://en.wikipedia.org/wiki/File:CAPE_vs_SHEAR.png&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;. Licensed under GFDL 1.2+/CC-ASA 3.0U.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;CAPE (convective available potential energy) is a measure of buoyancy and its opposite, &lt;a href=&quot;https://en.wikipedia.org/wiki/Convective_inhibition&quot; rel=&quot;noreferrer&quot;&gt;CIN&lt;/a&gt; (convective inhibition) is a measure of the negative buoyancy a parcel must overcome to reach its level of free convection.  You can have a lot of CAPE, but more than a little CIN can keep any thunderstorms from firing.  If you have no CIN on the other hand but lots of CAPE you'll generally get a mess of storms everywhere but nothing organized.  The bulk 0-6 km wind shear is a good predictor of the type of storms you can anticipate.  Little shear tends toward &lt;a href=&quot;https://en.wikipedia.org/wiki/Air-mass_thunderstorm&quot; rel=&quot;noreferrer&quot;&gt;air-mass thunderstorms&lt;/a&gt; while lots of shear tends toward &lt;a href=&quot;https://en.wikipedia.org/wiki/Supercell&quot; rel=&quot;noreferrer&quot;&gt;supercell thunderstorms&lt;/a&gt;.  In between these two are &lt;a href=&quot;https://en.wikipedia.org/wiki/Multicellular_thunderstorm&quot; rel=&quot;noreferrer&quot;&gt;multi-cell thunderstorms&lt;/a&gt;.  The shear will also influence whether multiple storms along a boundary stay discrete or build upscale into a linear feature (e.g. squall lines or &lt;a href=&quot;https://en.wikipedia.org/wiki/Squall_line&quot; rel=&quot;noreferrer&quot;&gt;QLCS&lt;/a&gt;).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What the above things tell you is whether the environment favors &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_convection&quot; rel=&quot;noreferrer&quot;&gt;convection&lt;/a&gt; and what type of convection.  It does not tell you if there will be a storm or not.  You can have a perfect environment for storms, but unless something acts to initiate convection, you won't have a storm.  Storms like to initiate along boundaries (cold fronts, dry lines, gust fronts, etc).  You can also initiate with daytime thermal boundary layer convection eroding CIN until parcels can freely convect.  Upper level divergence can also promote initiation by providing large scale ascent.  &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Putting this together, I'm looking at observations and model output to identify favorable storm environments.  I'm also looking at them for features that promote initiation.  As we near showtime, I'll also be looking at radar.  On the radar I'm looking for evidence of convergence zones (radar fine lines, fronts, etc) to narrow down where I'd expect storms to fire.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;†&lt;/sup&gt; The &lt;em&gt;Z&lt;/em&gt; suffix is shorthand for the historical Zulu time zone, which in modern times we call GMT or Greenwich Mean Time.  All meteorological products are referenced to this time zone and this is done for simplicity.  For example, no matter where you are on Earth, you know balloons are going to go up at 12Z and 00Z, and that the GFS will come out at 00,06,12 and 18Z.  The conversion to local time exactly that as from GMT or UTC.  For example 12Z on the east coast of the USA (in eastern &lt;em&gt;daylight&lt;/em&gt; time, EDT, at the time of this writing) is GMT-0400, so 12Z - 4 = 08, or 8 AM EDT (and 7 AM EST the other half of the year). &lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="269" LastEditDate="2014-07-11T08:37:07.920" LastActivityDate="2014-07-11T08:37:07.920" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2244" PostTypeId="2" ParentId="2226" CreationDate="2014-07-09T21:25:06.127" Score="21" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is there geological (or other physical) evidence here on Earth that confirms the moon once collided with the Earth?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No, there isn't. This is, however, plenty of evidence that the moon formed due to a collision of a third body (sometimes referred to as Theia) with the Earth, and the moon formed from the ring of debris that resulted from the collision. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This theory is often known as the &lt;em&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Giant_impact_hypothesis&quot;&gt;Giant Impact Hypothesis&lt;/a&gt;&lt;/em&gt; and searching for this term may help you find other links and references elsewhere.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If so what is that evidence?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;To summarise the geological evidence, much of it is &lt;strong&gt;indirect&lt;/strong&gt; evidence, in that it compares geology on the Moon with similar geology or features on the Earth, and draws conclusions to explain the similarities (or discrepancies).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because of the sheer size of the proposed impact, it would have likely reconfigured the surfaces of both bodies entirely, and so finding direct physical evidence on the Earth would be extremely unlikely. (e.g. a massive hidden crater would simply no longer exist)&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Geological Evidence&lt;/h2&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Moon rocks collected from the Apollo missions that have almost identical oxygen isotope ratios to similar rocks found on Earth of the same age.&lt;/li&gt;&#xA;&lt;li&gt;A large portion of the Lunar crust is made up of Anorthosite, which is indicative of a large melting event. (with the energy for this supplied from the impact)&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Zinc. Lunar rocks contain less zinc, but with heavier &lt;em&gt;isotopes&lt;/em&gt; of Zn than those found on Earth, which by contrast has lighter isotopes in greater abundance. This is consistent with zinc being depleted from the moon by evaporation, such as during a massive impact event.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Density and volatiles. The Moon is 25% less dense than the uncompressed density of Earth. It is severely depleted in volatiles, with practically no water and less than half the potassium abundance that Earth has. The combination of low density and lack of volatiles implies that the Moon was not a simple accretion of early solar system material, but resembles the Earth's mantle in bulk composition. Volatile material would have been vapourised by the impact. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The bulk composition of the Moon's crust. (This one does not actually involve the Earth, but I feel it is still important to mention.) The Moon's mantle and crust chemical composition &lt;em&gt;could&lt;/em&gt; be explained if the Moon had a large iron core, but its core is actually quite small.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h2&gt;Other Physical Evidence&lt;/h2&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The ratio of the Earth and Moon's mass far exceeds any other planet in the solar system, and this begs the question of how did so much material become in orbit of the Earth. (Not evidence as such, but raises the question in the first place)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Getting more indirect...there are bands of warm silica-rich dust orbiting nearby stars which is interpreted as planet-sized bodies having collided with each other, so there is precedent for similar events happening elsewhere in the galaxy. (Again, I realise this is one is not strictly answering the question, but Earth Scientists often have to look well outside the Earth to answer their questions!)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Hope this gets you started!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Update:&lt;/strong&gt;&#xA;I recently came across &lt;a href=&quot;http://www.ox.ac.uk/news/science-blog/where-did-moon-come&quot;&gt;this short article&lt;/a&gt;, which provides a summary of some of the latest thinking on the Moon's formation, including the Giant Impact Hypothesis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Sources: &lt;a href=&quot;http://books.google.co.uk/books/about/Planetary_Sciences.html?id=RaJdy3_VINQC&quot;&gt;de Pater and Lissauer (2010): Planetary Sciences&lt;/a&gt;; &lt;a href=&quot;http://www.es.ucsc.edu/~rcoe/eart206/canup_Moon_Nature_01.pdf&quot;&gt;Canup and Asphaug (2001), Nature&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="662" LastEditorUserId="725" LastEditDate="2014-11-20T05:00:29.270" LastActivityDate="2014-11-20T05:00:29.270" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2245" PostTypeId="2" ParentId="2240" CreationDate="2014-07-09T23:00:46.373" Score="14" Body="&lt;p&gt;Soil is an interesting case because although it is non-renewable (at any &lt;em&gt;useful&lt;/em&gt; rate) as a 'bulk material' once removed from the ground, the &lt;em&gt;nutrient&lt;/em&gt; content of soil can be renewed with fertilizers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What a soil-scientist would understand as 'soil' is ultimately produced from the physical and chemical breakdown of solid bedrock at the base of the soil horizon. The rate at which this happens for natural soil production can vary substantially depending on the climatic conditions and other factors, but typically could range from 0.1 to 2.0 mm/yr. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In many intensively farmed regions, (top)soil is being removed by erosion much faster than it is being replaced by natural process. Removal of vegetation cover is enough to expose bare soil to rainsplash erosion at rates much greater than it is renewed. Once soil is bare, it becomes much more susceptible to erosion. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think the additives you are referring to replenish the &lt;em&gt;nutrient&lt;/em&gt; content of the soil, and not the the bulk material that would be produced by bedrock decomposition. With careful management, the fertility of existing soil can be maintained. But if the soil is allowed to be washed off or erode, for all practical purposes, the rate of replenishment is not fast enough for it to be classed as renewable in that sense.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.soilerosion.net/doc/about_this_site.html&quot;&gt;This site&lt;/a&gt; has links to more aspects surrounding this issue.&lt;/p&gt;&#xA;" OwnerUserId="662" LastEditorUserId="662" LastEditDate="2014-07-11T00:56:48.420" LastActivityDate="2014-07-11T00:56:48.420" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2246" PostTypeId="1" AcceptedAnswerId="2248" CreationDate="2014-07-10T06:02:02.567" Score="10" ViewCount="2030" Body="&lt;p&gt;I came across a statement online that said that an average cloud has a weight of 1 million pounds. My main question is, does a cloud actually have &lt;em&gt;weight&lt;/em&gt; on Earth or was the term &quot;weight&quot; a colloquial expression meaning &quot;mass&quot;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From my understanding, weight is a force defined as W = mass × gravity, or essentially F = ma. Because the cloud is not falling, its acceleration is 0 -- that is, the acceleration of -9.8m/s&lt;sup&gt;2&lt;/sup&gt; exerted by Earth's gravity must be counteracted by another equal and opposite force in order for the cloud to be stationary in mid-air, hence the &quot;a&quot; portion of F=ma is 0, so F, and therefore weight, must be 0. Is this thinking correct?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, when the state changes from gas to liquid -- that is, when it starts raining - the water molecules in the liquid state obviously have weight. So my secondary question is, does a molecule's state change affect its weight? For gases which are &quot;lighter than air&quot;, is their weight negative? (I suspect yes because of the force equation).&lt;/p&gt;&#xA;" OwnerUserId="664" LastEditorUserId="725" LastEditDate="2014-12-09T06:02:55.470" LastActivityDate="2019-03-07T17:31:21.763" Title="Weight vs. Mass of Clouds" Tags="|atmosphere|clouds|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2247" PostTypeId="2" ParentId="867" CreationDate="2014-07-10T06:30:51.620" Score="4" Body="&lt;p&gt;I'm basing this answer off an article: &lt;em&gt;Kevin Lepot, Karim Benzerara, Gordon E. Brown Jr., Pascal Philippot (2008). 'Microbially influenced formation of 2.7 billion-year-old stromatolites'. Nature Geoscience Vol.1 No.2, pp.118–121&lt;/em&gt;. DOI: &lt;a href=&quot;http://dx.doi.org/10.1038/ngeo107&quot; rel=&quot;nofollow&quot;&gt;http://dx.doi.org/10.1038/ngeo107&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Instruments that are desirable (and are actually used) to study stromatolites/freshwater microbialites:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Raman microspectroscope&lt;/li&gt;&#xA;&lt;li&gt;Confocal laser scanning microscope&lt;/li&gt;&#xA;&lt;li&gt;Scanning transmission X-ray microscope&lt;/li&gt;&#xA;&lt;li&gt;Transmission electron microscope (TEM), including high-resolution TEM&lt;/li&gt;&#xA;&lt;li&gt;Near-edge X-ray absorption fine structure spectroscope&lt;/li&gt;&#xA;&lt;li&gt;The usual sets of fine analytical chemistry and microcutting tools&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;As you might suspect, this may require rather massive, power-hungry and bulky rovers. There is a solution and it's called &lt;strong&gt;sample return&lt;/strong&gt;. Although the tools and instruments are constantly evolving and undergoing miniaturization, a skilled and attentive lab researcher will find out more back here on Earth than a rover on Mars.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another consideration in favor of sample return is the verifiability of possibly sensational results - the sample will be curated and subdivided between universities and labs worldwide, applying diverse techniques and not relying on a single set of ultra-costly but possibly systematically biased hardware.&lt;/p&gt;&#xA;" OwnerUserId="269" LastActivityDate="2014-07-10T06:30:51.620" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2248" PostTypeId="2" ParentId="2246" CreationDate="2014-07-10T10:19:41.500" Score="18" Body="&lt;p&gt;There are different senses of weight used within branches of physics and engineering. In the strictest physical sense &quot;weight&quot;, is given by &lt;em&gt;W = mg&lt;/em&gt;. i.e. &lt;strong&gt;weight is the force on an object due to gravity &lt;em&gt;alone&lt;/em&gt;&lt;/strong&gt;.  Clouds are not &quot;weightless&quot; in that sense, since they are not far enough away from the Earth to escape its gravitational pull. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason that clouds stay up in the sky is, as you say, because they are acted on by an equal and opposite force, namely the surrounding buoyancy of the air. Rain drops are formed by water molecules condensing around some sort of nucleus (a speck of dust, for example). This is triggered by the cooling of the cloud, or lifting to lower pressures, which reduces the moisture-carrying capacity of that particular &quot;parcel&quot; of air. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;While the arrangement of water molecules in the cloud make it light enough to be buoyant in the air, the arrangement of those same molecules in rain drops are not &amp;ndash; so they begin to fall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By analogy, I would think of the fact that a ship is buoyant, despite its huge mass, but if you 'condensed' the ship into a lump of steel with the same mass, it would obviously sink. It's &lt;em&gt;weight&lt;/em&gt; remains the same however, no mass has been removed, and the value of &lt;em&gt;g&lt;/em&gt; has not changed. So to answer your second question, no, phase changes do not affect weight. (Although strictly speaking, &lt;a href=&quot;https://physics.stackexchange.com/questions/87259/does-decrease-in-temperature-affect-mass-e-mc2&quot;&gt;in quantum physics it can do&lt;/a&gt; &amp;ndash; but the amount is negligible here)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gases which are &quot;lighter than air&quot; will eventually settle in a portion of the atmosphere where the surrounding gases are the same density. They are not weightless, nor do they have a negative weight. The molecules are still experiencing a force due to the Earth's gravity. &lt;/p&gt;&#xA;" OwnerUserId="662" LastEditorUserId="-1" LastEditDate="2017-04-13T12:40:15.470" LastActivityDate="2014-07-10T21:31:33.500" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2249" PostTypeId="1" AcceptedAnswerId="3033" CreationDate="2014-07-10T13:29:20.703" Score="19" ViewCount="1159" Body="&lt;p&gt;Venus is noted for its absence of spreading ridges, transform faults, and subduction zones, which are characteristic of plate tectonics on Earth. But given that it exhibits rift zones, mountain belts and other &quot;secondary&quot; features of tectonic activity, should it be considered tectonically active?&lt;/p&gt;&#xA;" OwnerUserId="662" LastActivityDate="2014-12-13T00:34:11.087" Title="Can Venus be considered to be tectonically active?" Tags="|plate-tectonics|planetary-science|tectonics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2250" PostTypeId="1" AcceptedAnswerId="2308" CreationDate="2014-07-10T17:52:58.270" Score="12" ViewCount="1948" Body="&lt;p&gt;From my understanding, the mantle is in a highly reduced state, so I can't understand why a volcano would give off a highly oxidised gas such as sulphur dioxide.&lt;/p&gt;&#xA;&lt;p&gt;Carbon dioxide is too an oxidised gas which is emitted by volcanoes, however I justify its emission because carbon dioxide is continually being fed into the mantle by the subduction of carbonate sediments, is this correct? If this is true, why is there still carbon dioxide emitted at mid-ocean ridges?&lt;/p&gt;&#xA;&lt;p&gt;Or is this all wrong, and the gases are being emitted because they are still being degassed from the solid mantle in the process if heterogenous separation which separated the atmosphere from the mantle. If &lt;strong&gt;this&lt;/strong&gt; is the case, why have all other gases been separated but not the two I have mentioned?&lt;/p&gt;&#xA;" OwnerUserId="389" LastEditorUserId="7064" LastEditorDisplayName="user889" LastEditDate="2022-11-01T16:41:29.313" LastActivityDate="2022-11-01T20:46:06.073" Title="Why do Volcanoes give out so much Sulphur Dioxide and Carbon Dioxide?" Tags="|geochemistry|volcanology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="2251" PostTypeId="1" CreationDate="2014-07-11T09:24:45.260" Score="9" ViewCount="154" Body="&lt;p&gt;Scientists are forecasting a weak to moderate El Niño event to emerge in the coming months, what causes this to happen? Once developed, how will the El Niño conditions effect progressive monsoon systems? &lt;/p&gt;&#xA;" OwnerDisplayName="user668" LastEditorUserId="111" LastEditDate="2014-12-21T21:38:22.827" LastActivityDate="2014-12-21T21:38:22.827" Title="Relation of El Niño to Monsoons" Tags="|meteorology|climate|enso|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2252" PostTypeId="1" AcceptedAnswerId="2254" CreationDate="2014-07-11T12:58:03.547" Score="13" ViewCount="187" Body="&lt;p&gt;On 2014-07-10, in the afternoon, the GOES East satellite image in the visible showed a mass of cloud in central North America. However, in the middle, the Great Lakes stood out in a most extraordinary way, since they were almost completely free of cloud. It was like a cookie-cutter. The cloud followed the outline of the lakes precisely. Why is that?&lt;img src=&quot;https://i.stack.imgur.com/Zqo5p.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a second view, from MODIS data: &lt;a href=&quot;https://earthdata.nasa.gov/labs/worldview/?switch=geographic&amp;amp;products=baselayers,MODIS_Aqua_CorrectedReflectance_TrueColor,!MODIS_Terra_CorrectedReflectance_TrueColor~overlays,!Reference_Labels,!Reference_Features,Coastlines&amp;amp;time=2014-07-10&amp;amp;map=-97.871327,36.796299,-75.371327,52.300205&quot; rel=&quot;nofollow noreferrer&quot;&gt;MODIS image of the Great Lakes&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="669" LastEditorUserId="669" LastEditDate="2014-09-30T01:02:37.733" LastActivityDate="2014-09-30T01:02:37.733" Title="Great Lakes - cookie cutter clouds" Tags="|meteorology|clouds|weather-satellites|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2253" PostTypeId="1" AcceptedAnswerId="3134" CreationDate="2014-07-11T13:32:59.370" Score="13" ViewCount="7087" Body="&lt;p&gt;I am struggling to understand the difference between &lt;em&gt;implicit&lt;/em&gt; methods and &lt;em&gt;explicit&lt;/em&gt; methods in numerical modelling of Earth processes, particularly when applied to modelling Earth systems in 2 or more dimensions, such as in NWP (Numerical Weather Prediction), for example.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand the basic principle for the &lt;strong&gt;explicit&lt;/strong&gt; method: that an explicit model would calculate the new value of each grid square independently for each time step, for example. The application of the &lt;strong&gt;implicit&lt;/strong&gt; method puzzles me though &amp;ndash; it seems to require knowledge of both the current state of a system and the &lt;em&gt;latter&lt;/em&gt;  state, before the latter state is even calculated? Is it somehow extrapolating the outcome?&lt;/p&gt;&#xA;" OwnerUserId="662" LastActivityDate="2014-12-24T17:49:47.783" Title="What are the differences between implicit and explicit methods when applied to modelling Earth systems?" Tags="|models|nwp|modelling|numerical-modelling|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2254" PostTypeId="2" ParentId="2252" CreationDate="2014-07-11T14:38:49.137" Score="11" Body="&lt;p&gt;There are a couple reasons for this.  First, Lake Michigan is still cold this time of year, relative to the land that surrounds it.  Warm air flowing over the lake will exchange heat and cool, reducing its buoyancy, which will alter the heights at which clouds will form and inhibit lift for surface parcels to achieve that height.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That helps explain the cloudlessness over the lake, but this extends a bit inland as well.  I'd have to do a little digging to verify this, but just from that image it looks like that demarcation of cloud/no cloud around the lake is a sea breeze front (or in this case, a lake breeze).  The daytime lake breeze flows inland from the water, rises over land and then flows back to the lake where it descends.  This will promote clouds where the circulation rises and inhibit them where the circulation falls.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There may also be an orographic effect on along the northern portion of western MI shore, as there are large sand dunes and hills in that area.  The upslope flow could be the reason the clouds hug that shore a bit closer than other regions around the lake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In summary, that looks like a really well defined lake breeze circulation, which explains the shape and location of the clouds.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-07-11T14:38:49.137" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2255" PostTypeId="1" CreationDate="2014-07-11T15:42:41.720" Score="11" ViewCount="353" Body="&lt;p&gt;I am modeling a fault surface (which I consider to be a plane rectangle). I got the area of the surface, but the orientation is unknown, which can be found out if the aspect ratio of the rectangle is known. Is there a way to find this using the average slip rate?&lt;/p&gt;&#xA;" OwnerUserId="590" LastEditorUserId="502" LastEditDate="2014-08-29T06:18:09.673" LastActivityDate="2014-08-29T06:18:09.673" Title="Relation between fault rupture aspect ratio and slip rate?" Tags="|geophysics|seismology|earthquakes|plate-tectonics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2256" PostTypeId="2" ParentId="2227" CreationDate="2014-07-11T16:43:53.270" Score="6" Body="&lt;p&gt;The Rossby radius of deformation (&lt;span class=&quot;math-container&quot;&gt;$\lambda_{R}$&lt;/span&gt;) is a length scale over which  adjustment will occur while a system approaches geostrophic equilibrium.  In my class noted I have this defined as the distance at which buoyancy becomes as important as rotation.&lt;/p&gt;&#xA;&lt;p&gt;Some examples are given &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Rossby_radius_of_deformation&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; but do not show their derivation.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The distance that cold pools of air can spread under the influence of the Coriolis force.&lt;/p&gt;&#xA;&lt;p&gt;A cold pool will initially spread out toward and under warmer air because of higher pressure under the cold, denser air. However, as the spreading velocity increases, the Coriolis force will increasingly turn the velocity vector until it is parallel, rather than perpendicular, to the pressure gradient. At this point, no further spreading will occur and the winds will be in geostrophic equilibrium. The final equilibrium distance traveled by the edge of the cold air equals the external Rossby radius of deformation, &lt;span class=&quot;math-container&quot;&gt;$\lambda_{R}$&lt;/span&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\lambda_{R} = {\sqrt{(gH\Delta\theta/\theta_0)}\over f_c}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I'm not familiar with the particular derivation used to come up with the 1000-2000 km &lt;span class=&quot;math-container&quot;&gt;$\lambda_R$&lt;/span&gt; for synoptic weather patterns but it likely starts with Rossby waves and a wave solution for their propagation.&lt;/p&gt;&#xA;&lt;p&gt;One example derivation for &lt;span class=&quot;math-container&quot;&gt;$\lambda_{R}$&lt;/span&gt; I can think of is in a shallow water model in a rotating frame from Holton (2004) p 211.  In his setup he starts with the height (&lt;span class=&quot;math-container&quot;&gt;$h'$&lt;/span&gt;) of his shallow fluid with a discontinuity along &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; defined as &lt;span class=&quot;math-container&quot;&gt;$h' = h_0 \mathrm{sign}(x)$&lt;/span&gt; where sign(&lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt;) is the sign of x.  As the fluid equilibrates, the heights will change at the discontinuity and at some distance from the discontinuity.  How far away?  That is what the Rossby radius of deformation tells us.  For Holton's shallow water model, he finds &lt;span class=&quot;math-container&quot;&gt;$\lambda_{R} \equiv f_0^-1\sqrt{gH}$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$f_0$&lt;/span&gt; is the Coriolis parameter, &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; is gravity and &lt;span class=&quot;math-container&quot;&gt;$H$&lt;/span&gt; is the mean depth of the fluid.  At distances less than &lt;span class=&quot;math-container&quot;&gt;$\lambda_{R}$&lt;/span&gt;, we will observe the height changes but further than &lt;span class=&quot;math-container&quot;&gt;$\lambda_{R}$&lt;/span&gt; we will not notice any changes in fluid height.  In this case we can interpret the Rossby radius of deformation as the length scale over which the height field changes during geostrophic adjustment.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-07-11T16:43:53.270" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2257" PostTypeId="1" AcceptedAnswerId="2258" CreationDate="2014-07-11T23:35:58.190" Score="19" ViewCount="7056" Body="&lt;p&gt;In the atmospheric dynamics research community, many colleagues of mine happen to use atmospheric models that have &lt;strong&gt;&lt;em&gt;non-hydrostatic&lt;/em&gt;&lt;/strong&gt; equation solvers, e.g. the &lt;a href=&quot;http://www.metoffice.gov.uk/research/modelling-systems/unified-model&quot;&gt;UK MetOffice model&lt;/a&gt;, and &lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/&quot;&gt;WRF-ARW&lt;/a&gt;: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The equation set for ARW is fully compressible, Eulerian and nonhydrostatic...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There are another group of models that use a &lt;strong&gt;&lt;em&gt;hydrostatic&lt;/em&gt;&lt;/strong&gt; solver by default (e.g. &lt;a href=&quot;http://www.ecmwf.int/en/research/modelling-and-prediction/atmospheric-dynamics&quot;&gt;ECMWF&lt;/a&gt;), and presumably make the following assumption about the Earth's atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Hydrostatic equilibrium describes the atmospheric state in which the upward directed pressure gradient force (the decrease of pressure with height) is balanced by the downward-directed gravitational pull of the Earth. On average the Earth’s atmosphere is always close to hydrostatic equilibrium.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My question is what are the applications of each type of solver, i.e. when would you chose to use a non-hydrostatic model over a hydrostatic one? (which is presumably less computationally expensive?)&lt;/p&gt;&#xA;" OwnerUserId="662" LastEditorUserId="64" LastEditDate="2014-07-12T02:42:17.057" LastActivityDate="2015-01-14T20:00:52.023" Title="What are the applications of hydrostatic solvers vs non-hydrostatic solvers in numerical weather prediction?" Tags="|meteorology|models|nwp|weather-forecasting|numerical-modelling|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2258" PostTypeId="2" ParentId="2257" CreationDate="2014-07-12T02:40:10.400" Score="16" Body="&lt;p&gt;The hydrostatic approximation begins with the full 3-D momentum equation (Navier-Stokes) and through scale analysis the vertical momentum equation reduces to:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\dfrac{\partial p}{\partial z} = -\rho g$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a balance between the vertical pressure gradient force and gravity with no net acceleration.  This tends to hold for atmospheric phenomena that are much wider than they are tall.  On the synoptic scale where vertical motions are on the order of 1 cm s$^{-1}$ this holds, but in a thunderstorm where updrafts can attain speeds of 100 m s$^{-1}$ this approximation doesn't work.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A hydrostatic model uses the hydrostatic approximation in place of an equation for $w$, while a non-hydrostatic model uses the momentum equation for $w$.  As the ECMWF  page you link to suggests, models with low grid resolution can get by with the hydrostatic approximation.  A model with dx=dy=10 km means the grid volume is 100 km$^{2}$ times whatever the vertical grid spacing is.  The $w$ value for that grid box needs to be representative of the entire volume and you aren't going to explicitly resolve convection at this resolution (convection will be parameterized and in general a model can only resolve features that are about 4x bigger than the grid spacing). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you reduce grid spacing (increase resolution) and start to resolve non-hydrostatic features (thunderstorm updrafts, downdrafts, etc), then you need to make sure you are using a non-hydrostatic solver.  For high resolution operational regional modeling and research modeling in the mesoscale using WRF-NMM, WRF-ARW, CM1, ARPS you'll find non-hydrostatic solvers.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The non-hydrostatic solver is more computationally expensive than a hydrostatic solver, and is often found in higher resolution models which themselves are more computationally expensive than coarse grids. &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-07-12T02:40:10.400" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2259" PostTypeId="1" CreationDate="2014-07-12T03:16:08.297" Score="11" ViewCount="533" Body="&lt;p&gt;On the upper Mississippi in Illinois and southern Wisconsin, the river is bounded by hills and bluffs which  define the outer edges of the flood plain. There are similar configurations for some of  its tributaries, specifically the Illinois, the Rock and the Wisconsin Rivers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is whether the hills preexisted the  course of the river or did the river in some way cause the hills  to &quot;appear&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are the hills all glacial deposits which guided the course of river?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand  erosion   formed the bluffs  at Wisconsin Dells and Starved Rock, but why did the river flow there in the first place?&lt;/p&gt;&#xA;" OwnerUserId="657" LastEditorUserId="662" LastEditDate="2014-07-12T13:33:40.587" LastActivityDate="2014-12-10T10:27:00.833" Title="The river or the hills; which came first?" Tags="|rivers|geomorphology|glaciation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2260" PostTypeId="2" ParentId="2255" CreationDate="2014-07-12T07:03:19.090" Score="4" Body="&lt;p&gt;Ok, so this is a somewhat complicated question, and while this isn't a full answer I think I may be able to help you find the right direction. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It sounds like you are doing a completely theoretical study, so in this case I would advise you to look at Fault Maximum Displacement vs Fault Length Ratios (commonly referred to as D/L in te tectonics community). Here is an older but good study on D/L ratios: &lt;a href=&quot;ftp://ftp.gps.caltech.edu/pub/avouac/OwensValley/Dawers-Geology-1993.pdf&quot; rel=&quot;nofollow&quot;&gt;ftp://ftp.gps.caltech.edu/pub/avouac/OwensValley/Dawers-Geology-1993.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You will have to make some assumptions based on the type of faulting that occurs in your model. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found a observational study on D/L ratios and slip rate: &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0191814101000360&quot; rel=&quot;nofollow&quot;&gt;http://www.sciencedirect.com/science/article/pii/S0191814101000360&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which seems to be a well cited article on the subject. It seems there is some correlation, but perhaps it is different depending on the area. I know that Mars, Earth, and Icy Moons around Jupiter/Saturn all have different average D/L ratio which is directly correlated to the strain rates and material properties. Slip rate should have a similar, if not identical correlation (though slip is usually calculated on the surface where strain is often subsurface from my understanding).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What software are you using to model this fault surface? Is it a homebrew or is it a community code? I realize you might need to be a little secretive about what you are researching when posting on the internet, but a little more information might or might not go a long way in helping people provide a better answer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hopefully this helped.&lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="32" LastEditDate="2014-07-12T07:17:38.947" LastActivityDate="2014-07-12T07:17:38.947" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2261" PostTypeId="2" ParentId="2259" CreationDate="2014-07-12T11:22:01.530" Score="11" Body="&lt;p&gt;This is a kind of chicken or egg question, since there was never really a point at which there was no river flowing, or no hills to flow around.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;My question is whether the hills preexisted the course of the river or did the river in some way cause the hills to &quot;appear&quot;. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Most of the area which you describe along the Mississippi is formed of sand, gravel and till deposited by glaciers in the previous two glaciations. Though there would have been solid bedrock beneath it all before that, complete with hills and rivers flowing across the landscape. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rivers flow along the path of least resistance over the landscape under the influence of gravity. This means that, in general, they will take the route with the steepest downhill gradient from their source to the sea.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Are the hills all glacial deposits which guided the course of river?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The hills formed by glacial deposits would indeed have influenced the course of river after de-glaciation occurred. Though the flowing glacier will have shaped the hills in the first place.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the same time, the river will be eroding the material through which it flows, so it is constantly (but very slowly) carving out new formations in the landscape. Fluvial landscapes tend to produce very &lt;em&gt;dendritic&lt;/em&gt; landscapes &amp;ndash; that is, comprising of a dense network of channels with many small tributaries &amp;ndash; in comparison to landscapes formed by glaciers. In this sense, the river will be causing new hills to 'appear' as it carves out new valleys and tributaries into the glacial material. Some of the smaller hills in the area may well have been formed entirely post-glacially.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Summary:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A mixture of both really. River courses are influenced by existing topography, but they also have the power to carve out new features into the landscape.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Afterthought:&lt;/em&gt;&lt;/strong&gt;&#xA;If you go back far enough in Earth history, before the formation of water at the surface, there would have been some sort of topography (hills). So you could argue that ultimately the hills came first.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Sources&lt;/em&gt;: Bennett and Glasser (2009) &lt;em&gt;Glacial Geology&lt;/em&gt;; Anderson and Anderson (2010) &lt;em&gt;Geomorphology&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="662" LastEditorUserId="662" LastEditDate="2014-12-10T10:27:00.833" LastActivityDate="2014-12-10T10:27:00.833" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2262" PostTypeId="2" ParentId="2176" CreationDate="2014-07-13T03:59:32.983" Score="10" Body="&lt;p&gt;Based on past  events supported by archeological finds  climate change &lt;em&gt;will&lt;/em&gt; affect it.&#xA;Here is a short quote from an about.com referencing National Geographic &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;... recent excavations at the site of Gobero in Niger indicate.&#xA;  Gobero is a cemetery site, including at least 200 human burials&#xA;  located on top of a ridge or set of ridges, sand dunes with a hard&#xA;  calcrete-fringe. These burials occurred in two periods of settlement:&#xA;  7700-6200 BC (called Kiffian culture) and 5200-2500 BC (called&#xA;  Tenerean culture).&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;There, explorations by a team led by National Geographic&#xA;  Explorer-in-Residence and University of Chicago paleontologist Paul C.&#xA;  Sereno, have illuminated some small part of the last 10,000 years of&#xA;  the Saharan ecosystem. &quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Some references cited include&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Sereno, Paul C., et al. 2008 Lakeside Cemeteries in the Sahara: 5000&#xA;Years of Holocene Population and Environmental Change. PLoS ONE&#xA;3(8):e2995. Free article download available&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Green Sahara: National Geographic Magazine September 2008.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;People lived on the edge of the desert thousands of years ago since&#xA;  the last ice age. The Sahara was then a much wetter place than it is&#xA;  today. Over 30,000 petroglyphs of river animals such as crocodiles[8]&#xA;  survive, with half found in the Tassili n'Ajjer in southeast&#xA;  Algeria.... The modern Sahara, though, is not lush in vegetation,&#xA;  except in the Nile Valley, at a few oases, and in the northern&#xA;  highlands, where Mediterranean plants such as the olive tree are found&#xA;  to grow. The region has been this way since about 1600 BCE (aka as BC&#xA;  or  4600 years ago), after shifts in the Earth's axis increased&#xA;  temperatures and decreased precipitation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Citation: American Geophysical Union. &quot;Sahara's Abrupt&#xA;Desertification Started By Changes In Earth's Orbit, Accelerated By&#xA;Atmospheric And Vegetation Feedbacks.&quot; ScienceDaily. ScienceDaily, 12&#xA;July 1999. .&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Within the Holocene era, roughly the last 11,000 years, meaning the time frame within which the Western Sahara was sufficiently habitable to support a cemetery,  we have experienced a  &quot;little ice age&quot;. The Holocene is generally described as beginning at the end of the last glacial period. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There has been climate variation during the Holocene such that the Sahara could support human life. It is fair to extrapolate that any future climate change will also affect the Sahara.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you look at a world map you will see that the great dry deserts pretty much center  around the 20 degree latitude. Proximity to a large body of water does not mean that the  landmass can support vegetation. The Namib desert is south Africa stretches to the Atlantic coast as  the Atacama in Chile   has a very long boundary  with the Pacific. (The Atacama is also the driest place on earth)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If there is going to be an affect on a desert from climate change , it is possible that the  desert could extend to a major coast line. It would be reasonable that the North African coast could undergo desertification. It  is already  coterminous with the east and west coastal borders of Africa. If it expands , it can go north  or south. It already approaches the Mediterranean coast&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Presumably the Sahel could also become drier and there is some indication this has been happening. The Sahel is where we find the great savannahs. That  region is most at risk for increased temperature or aridity. Movement in eh other direction- milder temperatures and  more  rain would be beneficial  and supportive of  animals and human habitation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The arid region and the mean temperatures in the western Sahara are sufficiently  large that it seems unlikely the Hadley cell formation would be affected, but I am not a meteorologist, so I defer to  them on that point.&lt;/p&gt;&#xA;" OwnerUserId="657" LastEditorDisplayName="user889" LastEditDate="2014-12-24T22:50:05.130" LastActivityDate="2014-12-24T22:50:05.130" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2263" PostTypeId="1" CreationDate="2014-07-13T05:57:57.703" Score="14" ViewCount="277" Body="&lt;p&gt;I have done some simple analyses of historical surface temperature&#xA;from the NOAA &lt;a href=&quot;http://www.cpc.ncep.noaa.gov/products/wesley/reanalysis.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCAR/NCEP reanalysis&lt;/a&gt; (downloaded from &lt;a href=&quot;ftp://ftp.cdc.noaa.gov/Datasets/ncep.reanalysis.dailyavgs/surface/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ftp://ftp.cdc.noaa.gov/Datasets/ncep.reanalysis.dailyavgs/surface/air.sig995.*.nc&lt;/a&gt;).&#xA;It consists 66 years of daily temperature values on a 73*144 point grid. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The analyses I have done range from doing a simple historical average for each grid point to trying various matrix decomposition methods such as SVD, NMF &amp;amp; ICA to try identify interesting patterns and applying simple image processing filters to view the results.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the recurring features showing up in different analyses are wavelike pattern most prominent approximately along the Humboldt, Equatorial, Gulf Stream currents. These patterns appear to have a wave length of ~550 km. This is not something I would expect to see in temperature distribution data. The natural thought is that they are some kind of artifact, but they appear across range of algorithms and parameter settings. They also appear in analyses of subsets of the data. This leads me to think that these patterns really are in the data, though they could be some kind of artifact of the data collection process or reanalysis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://azimuth.mathforge.org/discussion/1387/odd-patterns-in-temperature-data&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; is a short discussion of these patterns.&#xA;I would like to find out:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;if similar patterns have been observed in other analyses&lt;/li&gt;&#xA;&lt;li&gt;suggestions for convincingly determining if these patterns are physical or some kind of artifact&lt;/li&gt;&#xA;&lt;li&gt;suggestions of plausible explanations if these patterns are physical&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Here are some processed images that show the patterns:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/QzKKC.png&quot; alt=&quot;historical median and local rank filter thereof&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The image on the right is a local rank filter applied to the historical median at each grid point (left image).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/icBtF.png&quot; alt=&quot;ICA components&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;10 ICA components of the date by grid point matrix for the Pacific region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The patterns are strongest in the second row images and the left image on the third row. They appear to emanate from the coast of Chile NW towards the central pacific. The images are histogram equalized to improve contrast.&lt;/p&gt;&#xA;" OwnerUserId="673" LastEditorUserId="3061" LastEditDate="2015-08-21T11:05:45.000" LastActivityDate="2015-08-26T19:36:45.703" Title="Odd structures in 66 year NCEP daily temperature reanalysis" Tags="|climate|temperature|ocean-currents|ncep|reanalysis|" AnswerCount="1" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="2264" PostTypeId="1" AcceptedAnswerId="2266" CreationDate="2014-07-13T12:45:16.327" Score="8" ViewCount="838" Body="&lt;p&gt;I saw many pictures of noctilucent clouds in the UK. Is it a phenomenon only visible in the UK or we can see it somewhere else?&lt;/p&gt;&#xA;" OwnerUserId="675" LastActivityDate="2014-12-22T12:12:43.760" Title="Where can we see the noctilucent clouds?" Tags="|clouds|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2265" PostTypeId="2" ParentId="1035" CreationDate="2014-07-13T13:10:34.817" Score="7" Body="&lt;p&gt;Oxford Instruments used to sell a VSM (vibrating sample magnetometer) with an oven option up to 1000K. Mounting samples was made using a &quot;non-magnetic&quot; paste/cement. You may want to look into that.&lt;/p&gt;&#xA;" OwnerUserId="676" LastActivityDate="2014-07-13T13:10:34.817" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2266" PostTypeId="2" ParentId="2264" CreationDate="2014-07-13T17:17:33.673" Score="6" Body="&lt;p&gt;Noctilucent clouds form during summer at high latitudes, such as between 50 and 70°N.  They are noctilucent because at their high elevation (80 km), the sun is still shining, although the sun is below the horizon at ground level.  Due to this high elevation, you can see them from several 100s of km south of their actual location.  This means the ideal viewing location is at around 55–60°N; the night there gets dark enough throughout the summer, while the noctilucent clouds a bit further north are still sunlit.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you go too far north, you will not see them very well, because the night will be too bright.  I lived for 5 years at 68°N, and although they could easily be detected by ground-based lidar, I never saw any myself.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="56" LastEditDate="2014-07-14T12:35:49.993" LastActivityDate="2014-07-14T12:35:49.993" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2267" PostTypeId="1" AcceptedAnswerId="2268" CreationDate="2014-07-14T19:04:51.600" Score="5" ViewCount="200" Body="&lt;p&gt;I am designing a fantasy setting for pen-and-paper role-playing (and potential novel) purposes. I have decided that a continent be situated right on a Pole of some imaginary planet with axial tilt comparable to Earth. My question is: is it possible to achieve environmental conditions in the Continent at least somewhat similar to those of current-day Europe?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My understanding of Earth climate is that the poles, while extremely cold, are also very dry in terms of precipitation. I have understood that this is mostly due to the axial tilt but I'm not sure. I have heard that in a warmer part of Earth's history the poles had vegetation - is this possible even with the ever-present high-pressure zone?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I guess one way the continent could be habitable is to be full of freshwater rivers, originating from glaciers high atop of some mountains. I guess such mountains are plausible near the pole (I don't think the movement and mutual interaction of continental plates are somehow dependent of the latitude, are they?)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank's in advance for your great contributions!&lt;/p&gt;&#xA;" OwnerUserId="679" LastEditorUserId="5594" LastEditDate="2017-10-26T08:27:53.983" LastActivityDate="2017-10-26T08:27:53.983" Title="What would the geology and climate of a supposed landmass near the pole be like, assuming a thoroughly warmer planet?" Tags="|climate|geology|poles|" AnswerCount="2" CommentCount="4" ClosedDate="2017-10-26T12:31:40.767" ContentLicense="CC BY-SA 3.0" />
  <row Id="2268" PostTypeId="2" ParentId="2267" CreationDate="2014-07-16T12:07:07.087" Score="5" Body="&lt;p&gt;For a very basic explanation of why poles are the way they are, note that the amount of solar radiation coming from the sun is spread over a larger area at the pole. Therefore you get less radiation per square meter. As a result it is colder.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cold air can hold less water vapour. As such it is very dry (in terms of water mass per air volume) in cold regions. Dry air obviously can provide less precipitation. If your polar continent is warmer, you'll see more precipitation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Large-scale weather phenomena are indeed mostly driven by Earth's rotation. As such you have somewhat more stable conditions along the poles. However, complex topography (i.e. mountains) can severely interfere with these conditions. This is the reason why the stratospheric ozone hole is much smaller in the northern hemisphere than in the southern hemisphere: There is much more mixing between differnt air regions in the north. In the troposphere this effect is even more pronounced.&lt;/p&gt;&#xA;" OwnerUserId="681" LastActivityDate="2014-07-16T12:07:07.087" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2269" PostTypeId="2" ParentId="2163" CreationDate="2014-07-17T13:04:57.147" Score="7" Body="&lt;p&gt;Since the sound waves propagate not from a single point source but along the length of the lightning's path, the sound origin's varying distances from the observer can generate a rolling or rumbling effect. Perception of the sonic characteristics is further complicated by factors such as the irregular and possibly branching geometry of the lightning channel, by acoustic echoing from terrain, and by the typically multiple-stroke characteristic of the lightning strike.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition, thunder will sound louder when the air near the ground is colder and the air higher in the atmosphere is warmer. This is because the acoustic shock waves get &quot;trapped&quot; in the cold air. Such a temperature difference, called an inversion, tends to happen at night, which is why thunder often sounds louder at night.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;http://en.wikipedia.org/wiki/Lightning#Thunder&quot;&gt;Wikipedia&lt;/a&gt; and &lt;a href=&quot;http://www.wisegeek.org/what-causes-thunder.htm&quot;&gt;wisegeek.org&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="115" LastEditorUserId="115" LastEditDate="2014-07-18T00:23:18.977" LastActivityDate="2014-07-18T00:23:18.977" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2270" PostTypeId="1" CreationDate="2014-07-17T14:17:04.503" Score="12" ViewCount="147" Body="&lt;p&gt;I have a dataset consisting of irregularly spaced points in the ocean. For each point I have coordinates and a data value.&#xA;I need to interpolate to a regular grid. So far, so easy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are areas of land within the area covered by the dataset, and in the original dataset there are simply no points there. I have polygons of the land boundaries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I need to exclude the land from the output. This is fairly straightforwardly accomplished by checking which of the points on the target grid are within the polygons and removing them.&#xA;However, I also need to make sure that whatever interpolation technique is used does not consider points that are (for example) the other side of a peninsula - potentially a short distance away in a straight line, but a long way (or possibly not connected at all) by sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm sure that this must be a solved problem - I imagine any GIS package will have a way to deal with it - but I am at a loss as to what search terms to use in looking for the solution. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have been debating whether to ask this question here, or on stats.SE, or on GIS.SE, or on Stackoverflow... but let's see how it goes.&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="111" LastEditDate="2014-07-17T18:56:07.240" LastActivityDate="2014-07-26T14:13:21.660" Title="Interpolating spatial data in contiguous sea areas only" Tags="|ocean|geospatial|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2271" PostTypeId="2" ParentId="2270" CreationDate="2014-07-17T14:35:24.700" Score="2" Body="&lt;p&gt;Partial answer: after some further research: It looks as though the terminology that I am looking for is &quot;Breakline&quot;. I need to define my coastlines as being breaklines. Now I need to figure out how to implement them in the languages that I am using, but that's probably a question for GIS.SE or Stackoverflow.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2014-07-17T14:35:24.700" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2272" PostTypeId="2" ParentId="2270" CreationDate="2014-07-17T15:32:59.377" Score="7" Body="&lt;p&gt;A very neat approach for optimal interpolation, which consider not only breaklines along the coast but also anisotropies caused by currents and horizontal diffusion, was given by &lt;a href=&quot;http://dx.doi.org/10.1016/S0278-4343(01)00007-3&quot;&gt;Lynch &amp;amp; McGillicuddy (2001)&lt;/a&gt;. Their approach is quite elegant and takes advantage of the finite element methodology to avoid the transfer of information across boundaries.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-07-17T15:32:59.377" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2273" PostTypeId="2" ParentId="891" CreationDate="2014-07-17T17:13:53.253" Score="6" Body="&lt;p&gt;In the blog post, &quot;[They] start with a pressure gradient.&quot; So I'll discuss how a pressure gradient force develops at the jet streak level and why it develops at the jet streak level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First let's go over some basics. From the meteorological perspective, one can think of pressure as the amount of air mass above a point (gravity provides the acceleration). So high pressure means relative large amounts of air mass above a point and low pressure means a relatively low amount of air mass above a point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, think of two columns of air that start at surface and go into space. One column is really cold and the other column is really warm. Warm air is less dense than the cold air. If the cold air column and the warm column have the same amount of mass, the warm air column will be taller. If the two columns have the same mass, the surface pressure of the two columns will be the same.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we travel up these two columns we would expect the pressure to decrease with them as the amount of mass above us decreases. The pressure in the cold column would decrease faster than the mass in the warm column as we travel up the columns. This means at a certain height, say 10 km, the pressure in the warm column will be much greater than in the cold column (see image below). This is a pressure gradient and causes the jet streak in the link you posted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So how do we get cold air column next to warm columns? Those are fronts! A northern hemisphere warm front typically will have cold air to the north and warm air to the south. So the pressure gradient force at 10 km above the surface (about jet streak level) will be from south to north (note: the pressure gradient is from north to south in this example). Wind wants to go from south to north but is deflected by the Coriolis force as explained in the blog post. Now check out a weather map, you'll find the jet streak will be over a surface warm front!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, as we keep going up, the maximum pressure gradient will be at the jet streak level. Above the jet streak level, is the stratosphere which contains ozone. O-zone absorbs radiation and warms the air around it. The stratosphere starts at a lower altitude over cold surface air, so our pressure gradient begins to shrink above the jet streak. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, the jet streak is at the maximum pressure gradient. Which occurs above the boundary of cold air and warm at the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/6DDeN.gif&quot; alt=&quot;Temperature and pressure within a column&quot;&gt;&lt;br&gt;&#xA;&lt;sub&gt;From: &lt;a href=&quot;http://apollo.lsc.vsc.edu/classes/met130/notes/chapter10/graphics/pf_xsect2.free.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://apollo.lsc.vsc.edu/classes/met130/notes/chapter10/graphics/pf_xsect2.free.gif&lt;/a&gt; &lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This picture does a good job of showing how cold air will have lower pressure than warm air aloft.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: I should mention, fronts and jet streaks are kinda a chicken and egg scenarios. They each cause each other to some degree.&lt;/p&gt;&#xA;" OwnerUserId="684" LastEditorUserId="684" LastEditDate="2014-07-17T20:52:14.663" LastActivityDate="2014-07-17T20:52:14.663" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2274" PostTypeId="2" ParentId="987" CreationDate="2014-07-17T17:32:42.933" Score="4" Body="&lt;p&gt;On the east side of the Pacific Ocean, there are cold currents coming the poles going towards the equator. The cold currents makes it so there is almost a permanent cold air mass above the eastern portion of the ocean. As warmer air is blown over this colder air, it must go above the colder air. The warmer air expands, temperature decreases, becomes saturated and the stratus clouds form!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cold currents are there because of the semi-permanent high pressure system in the mid-latitudes of the ocean. The winds are equator-ward on the east side of high pressure systems. This drives the ocean currents to be equator-ward on the east side of the ocean.&lt;/p&gt;&#xA;" OwnerUserId="684" LastEditorUserId="64" LastEditDate="2014-07-17T19:57:27.913" LastActivityDate="2014-07-17T19:57:27.913" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2275" PostTypeId="1" CreationDate="2014-07-18T06:04:54.657" Score="12" ViewCount="414" Body="&lt;p&gt;I heard that groundwater is rich in minerals and fluorides, but I have no clear thoughts on what else it contains and whether the ground water differs from area to area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can someone please shed some light about what groundwater actually consists of? Is it drinkable? &lt;/p&gt;&#xA;" OwnerUserId="78" LastEditorUserId="725" LastEditDate="2014-11-18T11:58:09.963" LastActivityDate="2014-11-18T13:35:01.850" Title="What does groundwater consist of?" Tags="|geochemistry|hydrology|groundwater|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2278" PostTypeId="1" CreationDate="2014-07-18T11:06:09.183" Score="8" ViewCount="445" Body="&lt;p&gt;I have an hourly data file of a particular location which contains the following variables (extracted from the Meteonorm7.0 data base, for a typical one year of data):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;GlobHor (W/m&lt;sup&gt;2&lt;/sup&gt;)&lt;/strong&gt;: Horizontal Global Radiation.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;DiffHor (W/m&lt;sup&gt;2&lt;/sup&gt;)&lt;/strong&gt;: Horizontal Diffuse Radiation.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;KT&lt;/strong&gt;: Clearness Index.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Tamb (°C)&lt;/strong&gt;: Ambient temperature.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I´ve received the Monthly Accumulation values for each variable and I tried to check such values using just the hourly data. The Monthly Accumulation values of GlobHor and DiffHor are in kWh/m&lt;sup&gt;2&lt;/sup&gt;.month units.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the radiation variables, I´ve done the following:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;I've multiplied each hourly W/m&lt;sup&gt;2&lt;/sup&gt; value by the number of seconds in an hour (3600).&lt;/li&gt;&#xA;&lt;li&gt;Sum all the values in W/m&lt;sup&gt;2&lt;/sup&gt; for each month.&lt;/li&gt;&#xA;&lt;li&gt;Divide each monthly value by (3.6×1000000)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;It worked! For the ambient temperature, just the monthly average, and it worked too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I do not what has been done with the clearness index KT. It is not an average. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is there some special way, like with the Radiation data, to obtain the Accumulation Monthly values for the Clearness Index KT? Maybe something more complicated that is obtained just inside the Meteonorm7.0 data base?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="492" LastEditorUserId="192" LastEditDate="2014-12-10T19:06:32.333" LastActivityDate="2014-12-10T19:06:32.333" Title="Calculating Monthly Accumulation value of the Clearness Index KT" Tags="|meteorology|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2279" PostTypeId="2" ParentId="2163" CreationDate="2014-07-18T16:16:02.763" Score="4" Body="&lt;p&gt;Geometry of the lightning channel controls the type and duration of the sound.  Imagine a lightning strike oriented directly away from you--the farthest point on it is much farther away than the nearest point, meaning that the thunder will be drawn out over a long time.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, if the lightning strike is perfectly vertical and you're standing a good distance away, the entire lightning channel is roughly the same distance from you, meaning the thunder arrives almost all at once.  This makes a sharp crack.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rough diagrams: if the lightning is the line and the observer is the dot, then the two extreme scenarios are as follows:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;______      .  : long, drawn out rumble&#xA;&#xA;&#xA;|&#xA;|&#xA;|           .  : sharp crack&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Also, low frequencies attenuate more slowly, so distant strikes will sound lower in pitch than nearby strikes.&lt;/p&gt;&#xA;" OwnerUserId="40" LastActivityDate="2014-07-18T16:16:02.763" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2280" PostTypeId="1" AcceptedAnswerId="2281" CreationDate="2014-07-19T20:53:57.987" Score="14" ViewCount="1091" Body="&lt;p&gt;The evidence seems clear that there is an interrelationship between solar luminosity, greenhouse gas concentrations, and temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has temperature as a function of luminosity and greenhouse gas concentrations been developed?  If so, what is the accuracy and precision?&lt;/p&gt;&#xA;" OwnerDisplayName="user641" LastEditorDisplayName="user641" LastEditDate="2014-07-19T21:53:24.993" LastActivityDate="2014-07-24T02:30:49.333" Title="Temperature as a function of luminosity and greenhouse gas concentrations" Tags="|temperature|climate-change|statistics|gas|solar-terrestrial-physics|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="2281" PostTypeId="2" ParentId="2280" CreationDate="2014-07-20T04:48:07.210" Score="10" Body="&lt;p&gt;You need a radiative transfer model and global climate model to do it with greenhouse gases.  you can derive the temperature without greenhouse gases as discussed below: &lt;img src=&quot;https://i.stack.imgur.com/yfm35.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The absorption is highly variable depending on wavelength and can be seen in this graphic:&lt;br&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/zDOdq.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Radiative transfer through the atmosphere is specific to pressure, temperature, and wavelength. So in order to calculate the contribution of greenhouse gases you need to know their concentration distribution both vertically and horizontally not to mention an accurate representation of the atmospheric conditions. It's not one general function... it's millions of functions that all get integrated together and vary dynamically in time and space. I suggest you look at the HITRAN database for the complexities in absorption potential of different greenhouse gases. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You may also be interested in climate sensitivity paramaters.&#xA;From wikipedia &lt;a href=&quot;http://en.wikipedia.org/wiki/Climate_sensitivity&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://en.wikipedia.org/wiki/Climate_sensitivity&lt;/a&gt; :&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;For coupled atmosphere-ocean global climate models (e.g. CMIP5) the climate sensitivity is an emergent property: it is not a model parameter, but rather a result of a combination of model physics and parameters. By contrast, simpler energy-balance models may have climate sensitivity as an explicit parameter.&#xA; (ΔTs) = λ (ΔRF)&#xA;The terms represented in the equation relate radiative forcing (RF) to linear changes in global surface temperature change (ΔTs) via the climate sensitivity λ.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is convenient because if you know the change in concentration of a gas and the corresponding RF you can compute a change in surface temperature.  Though, I believe the climate sensitivity parameters are particularly for certain time and concentration regimes.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2014-07-24T02:30:49.333" LastActivityDate="2014-07-24T02:30:49.333" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2283" PostTypeId="1" CreationDate="2014-07-23T15:52:14.180" Score="10" ViewCount="368" Body="&lt;p&gt;In &quot;An Introduction to Seismology, Earthquakes and Earth Structure&quot;, authors Seth Stein and Michael Wysession made the statement: &quot;Faulting will occur along the plane where the shear stress is the highest&quot;. However, no further clarification was given. What are the implications of this statement? Is the statement true? What are the processes that cause faulting to occur along the plane of maximum shear stress?&lt;/p&gt;&#xA;" OwnerUserId="594" LastEditorUserId="111" LastEditDate="2014-07-25T14:13:13.137" LastActivityDate="2015-07-29T04:29:12.733" Title="What is the reasoning behind the statement &quot;Faulting will occur along the plane where the shear stress is the highest&quot;?" Tags="|geology|earthquakes|geodynamics|structural-geology|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2284" PostTypeId="2" ParentId="986" CreationDate="2014-07-24T06:36:41.390" Score="2" Body="&lt;p&gt;The continued trend of a warming climate that is expected due to increased GHGs will lead to a net increase in total moisture, since the atmosphere can hold more water vapor at higher temperatures.  In general, the equatorial zones and poles will have a net increase in precipitation while lower mid-latitude zones will have reduced precip, with the rain belt moving poleward.   Climate models generally show a pole-ward shift of extra-tropical precipitation because the increased heat energy allows convective systems in low latitudes to loft the convective air higher up, which in turn leads to greater horizontal transport (generally poleward) before air completely descends and contributes to the development of an associated storm system. You can also expect the poleward shift since cold temperatures accelerate the precipitation process, and since systems will have to travel a little further poleward to reach those cold temperatures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A 2014 IPCC Technical Summary figure (below) shows change in precipitation forecasted ~65 yrs into the future.  The image on the left represents a best-case scenario if we reduce carbon emissions while the right represents more of a business-as-usual scenario.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/6i2qh.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2014-07-25T04:15:39.230" LastActivityDate="2014-07-25T04:15:39.230" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2285" PostTypeId="1" AcceptedAnswerId="2364" CreationDate="2014-07-25T11:59:08.110" Score="17" ViewCount="492" Body="&lt;p&gt;I read about the earthquake that took place in Japan in 2011, led to some small calving events in Antarctica (&lt;a href=&quot;http://www.nasa.gov/topics/earth/features/tsunami-bergs.html&quot;&gt;link&lt;/a&gt;). So, it makes me think if there is a big earthquake near or in Antarctica, can it lead to big calving events, like  loosing a whole floating ice shelf (event comparable to the &lt;a href=&quot;http://earthobservatory.nasa.gov/Features/WorldOfChange/larsenb.php&quot;&gt;Larsen ice shelf collapse&lt;/a&gt;)? Such an event can be very important, as ice shelves control the flow of ice from the various ice streams. And losing one leads to a significant speed up in the ice loss from the antarctic ice sheet. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or the somewhat plastic nature of ice makes it much resistant to a big Tsunami or earthquake, to the point that we don't need to consider it as a possibility at all. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I did some background study, and found there are not many active seismic regions near Antarctica as such. But there had been some big quakes in the nearby region in the &lt;a href=&quot;http://earthquakes.findthebest.com/d/b/Antarctica&quot;&gt;past&lt;/a&gt; few decades. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;UPDATE: Found a recent news article &lt;a href=&quot;http://news.yahoo.com/faraway-earthquake-triggered-antarctica-icequakes-170536448.html&quot;&gt;&quot;Faraway Earthquake Triggered Antarctica Icequakes&quot;&lt;/a&gt;. It doesn't answers the question, but provides more insight to the topic. You can also listen to this very cool audio &lt;a href=&quot;http://www.livescience.com/47266-antarctic-icequakes-triggered-by-earthquake-in-chile.html&quot;&gt;Antarctic Icequakes Triggered By Earthquake in Chile&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="206" LastEditorUserId="87" LastEditDate="2014-12-02T09:58:15.937" LastActivityDate="2014-12-02T09:58:15.937" Title="Can earthquakes contribute to Antarctic ice loss?" Tags="|seismology|earthquakes|glaciology|ice-sheets|antarctic|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2287" PostTypeId="1" AcceptedAnswerId="2299" CreationDate="2014-07-26T00:28:25.013" Score="13" ViewCount="822" Body="&lt;p&gt;Some researchers contend that increases in atmospheric CO&lt;sub&gt;2&lt;/sub&gt; (e.g., from anthropogenic emissions) will enhance plant growth in general.  &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;What is the level of that enhancement?  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Does the associated climate change simply make it easier for invasive species to propagate?  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Or is there really a valid case to be made that at some point, if concentrations of CO&lt;sub&gt;2&lt;/sub&gt; get high enough, forests and vegetative zones will somehow benefit?  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;In general, how will increases in CO&lt;sub&gt;2&lt;/sub&gt; and related climate change affect forests and other vegetative areas?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="543" LastEditorUserId="6129" LastEditDate="2020-05-09T12:20:36.317" LastActivityDate="2020-05-09T12:20:36.317" Title="How will increased $\ce{CO2}$ affect forests and other vegetative areas?" Tags="|climate-change|co2|carbon-cycle|forest|carbon|" AnswerCount="5" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="2288" PostTypeId="2" ParentId="2287" CreationDate="2014-07-26T10:04:43.853" Score="8" Body="&lt;p&gt;If you increase CO&lt;sub&gt;2&lt;/sub&gt; concentration and keep all other parameters at there current level, then biomass production should go up. The reason is simply that CO&lt;sub&gt;2&lt;/sub&gt; is one of the building blocks biomass is made of in photosynthesis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the real world it's trickier than that of course. Here you have to take into account how natural cycles will be affected by increased CO&lt;sub&gt;2&lt;/sub&gt; levels. Temperatures e.g. will go up which is expected to be beneficial for biomass production for moderate increases and becomes increasingly bad for higher increases. Precipitation patterns change, wind patterns and therefore soil erosion change etc. etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Chapter 7 of the IPCC report deals with the question how climate change affects biogeochemical cycles; biomass production is one of the parameters that go into the carbon cycle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To my knowledge biomass production is one of the parameters that benefit from moderate temperature increase but are expected to turn to their opposite around the 2-degree benchmark.  &lt;/p&gt;&#xA;" OwnerUserId="526" LastEditorUserId="725" LastEditDate="2014-12-10T07:02:48.290" LastActivityDate="2014-12-10T07:02:48.290" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2289" PostTypeId="2" ParentId="2270" CreationDate="2014-07-26T14:13:21.660" Score="7" Body="&lt;p&gt;Depending on the nature of the data, the approach of &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Hess, K., R. Schmalz, C. Zervas, and W. Collier, 2004. 'Tidal Constituent and  Residual Interpolation (TCARI): A New Method for the Tidal Correction of Bathymetric Data'. NOAA Technical Report NOS CS 4, Silver Spring, MD, 112 pp.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.nauticalcharts.noaa.gov/staff/docs/TCARI_CS4.pdf&quot;&gt;http://www.nauticalcharts.noaa.gov/staff/docs/TCARI_CS4.pdf&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;might be appropriate.  This boils down to solving a diffusion equation on an unstructured grid of the domain (TCARI also adds in some additional terms to help extrapolate trends in the data rather than a zero-gradient condition at the shorelines).  With just the diffusion problem, ~100 lines of python was enough to code this up for a San Francisco Bay domain with 500k cells used in the diffusion problem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Simon Wood and his then PhD student David Lawrence have also done a fair bit of work in this area, though my impression of their methods is that they are fairly expensive computationally for dense ocean observations.  (I'm going to feel silly if Simon W the asker is actually Simon Wood)&lt;/p&gt;&#xA;" OwnerUserId="24" LastActivityDate="2014-07-26T14:13:21.660" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2290" PostTypeId="1" AcceptedAnswerId="2306" CreationDate="2014-07-26T18:06:46.380" Score="13" ViewCount="654" Body="&lt;p&gt;In New Delhi, a lot of people say that the &#xA;&lt;a href=&quot;http://en.wikipedia.org/wiki/Aravalli_Range&quot;&gt;Aravali range &lt;/a&gt; used to be as tall as the Himalayas. How do scientists know that some mountain range used to be a lot taller millions of years ago, and what is the process by which mountains erode in general? &lt;/p&gt;&#xA;" OwnerUserId="711" LastEditorUserId="94" LastEditDate="2014-08-06T08:22:23.157" LastActivityDate="2017-03-25T03:10:21.930" Title="Determining the paleoelevation of mountain ranges" Tags="|earth-history|mountains|geography|paleogeography|topography|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2291" PostTypeId="2" ParentId="875" CreationDate="2014-07-27T20:06:06.497" Score="10" Body="&lt;p&gt;It's definitely possible, though not very likely as mentioned above. An unusually long subduction zone, like the Peru-Chile Trench, Aleutian Trench, or Japan-Kamchatka Trench would have to rupture &lt;strong&gt;in its entirety&lt;/strong&gt; to trigger one. In other words, it would have to be a quake that hits Russia and Japan at the same time, or a quake that hits Colombia, Ecuador, Peru, and Chile all at the same time, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, a Moment Magnitude 10 earthquake won't necessarily feel much different in terms of how far buildings move from, say, an 8 or 9. The shaking, however, would last for much longer ― about 30 minutes ― and be spread over a much larger area. And then, of course, there's the tsunami, which could hit land &lt;strong&gt;while the shaking is still going on&lt;/strong&gt;, greatly adding to the damage such a quake could cause.&lt;/p&gt;&#xA;" OwnerUserId="713" LastActivityDate="2014-07-27T20:06:06.497" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2292" PostTypeId="2" ParentId="2283" CreationDate="2014-07-28T06:04:51.167" Score="8" Body="&lt;p&gt;This statement is referring to depths within the crust where the lithostatic pressure is sufficiently high to suppress the formation of dilatant fractures. Rock is a brittle material, and if loaded to failure while under little or no confining pressure, it may fail by the growth of mode-I fractures oriented normal to the least compressive stress. At depth in the crust, the overburden weight of rock may cause sufficient pressure to suppress the growth of mode-I fractures, but if the stress is sufficient to cause mode-II fractures, these tend to grow in the plane of maximum shear stress.   &lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-07-28T06:04:51.167" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2293" PostTypeId="1" CreationDate="2014-07-28T09:11:10.607" Score="12" ViewCount="514" Body="&lt;p&gt;The rare earth elements form in magmatic rocks. The Iceland is very active vulcanic region, and it's, to my knowledge, entirely build from magmatic rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So it wouldn't be surprising if there were large amount of rare earth elements there? Are such deposits already documented?&lt;/p&gt;&#xA;" OwnerUserId="77" LastActivityDate="2014-08-01T10:19:13.980" Title="Are there significant amounts of rare earth elements on Iceland?" Tags="|geochemistry|resources|rare-earth|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2294" PostTypeId="1" CreationDate="2014-07-28T09:17:05.617" Score="18" ViewCount="852" Body="&lt;p&gt;Uranium's density is greater than most elements, so you would expect it to settle to the bottom of a volume of fluid. In the case of the Earth, which was molten in the beginning, you might then expect uranium to have settled to the core. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What stopped all of the Uranium from sinking down, so that we still have the deposits in the crust? Or more widely, why do we have heavy elements in the crust at all?&lt;/p&gt;&#xA;" OwnerUserId="77" LastEditorUserId="543" LastEditDate="2014-07-28T20:43:02.013" LastActivityDate="2014-07-31T15:24:22.460" Title="Why is there Uranium in Earth's Crust?" Tags="|geophysics|geochemistry|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2295" PostTypeId="1" CreationDate="2014-07-28T09:31:19.590" Score="13" ViewCount="843" Body="&lt;p&gt;Limestones are formed mostly from skeletal fragments of marine organisms. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, calcium carbonate dissolves naturally in water, so the living organisms are not the only source of it in water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it possible for limestone to form without living organisms? Are such deposits observed? Or is the presence of limestone a clear indicator that life is, or was present on given planet?&lt;/p&gt;&#xA;" OwnerUserId="77" LastEditorUserId="44" LastEditDate="2014-07-28T12:50:23.153" LastActivityDate="2014-07-28T13:05:55.117" Title="Formation of limestone without living organisms?" Tags="|sedimentology|rocks|limestone|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2296" PostTypeId="1" CreationDate="2014-07-28T09:50:58.727" Score="10" ViewCount="9683" Body="&lt;p&gt;How long does the formation of the amber take? Are there any approximation of the minimal time needed to convert resin into amber in the most favorable conditions? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would it be possible to produce amber on the timescale of a human lifespan?&lt;/p&gt;&#xA;" OwnerUserId="77" LastEditorUserId="87" LastEditDate="2014-08-15T10:06:53.553" LastActivityDate="2020-11-29T16:02:04.883" Title="How long does it take to form amber?" Tags="|taphonomy|amber|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2297" PostTypeId="2" ParentId="2295" CreationDate="2014-07-28T12:57:05.080" Score="7" Body="&lt;p&gt;Oolites are limestones that are usually considered as in-organic, although they may have bits of shell/etc in them.  These form by the precipitation of calcium carbonate around particles (sand, broken shell, etc) with a process comparable to that of an oyster.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some oolite references:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sandatlas.org/2012/09/oolite/&quot;&gt;http://www.sandatlas.org/2012/09/oolite/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Oolite&quot;&gt;http://en.wikipedia.org/wiki/Oolite&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recently I saw a reference that limestones do not deposit when Fe2+ is present. Unfortunately I can't find the reference now. If this is the case, then for the Earth, limestones require the &lt;strong&gt;indirect&lt;/strong&gt; presence of life. The evolution of cyanobacteria created free oxygen in the atmosphere and the dissolved in the oceans. Hence all dissolved iron was oxidised from Fe2+ (a green colour) to Fe3+ (orange colour).&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorUserId="44" LastEditDate="2014-07-28T13:05:55.117" LastActivityDate="2014-07-28T13:05:55.117" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2298" PostTypeId="1" CreationDate="2014-07-28T14:28:21.600" Score="8" ViewCount="201" Body="&lt;p&gt;I am looking for geometrical differences in subduction zones. What are the differences, in dip, curvature of the interface, thickness of the plates etc.?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are differences between the Chile and the Mariana type (as sketched &lt;a href=&quot;https://www.utdallas.edu/scimathed/resources/Melville/Fig%201-x.html&quot;&gt;here&lt;/a&gt;), but what about the other subduction zones like Alaska, Japan, Sumatra?&lt;/p&gt;&#xA;" OwnerUserId="646" LastEditorUserId="124" LastEditDate="2014-08-06T05:14:35.047" LastActivityDate="2014-08-06T09:59:47.667" Title="Geometrical differences of subduction zones" Tags="|geophysics|plate-tectonics|subduction|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2299" PostTypeId="2" ParentId="2287" CreationDate="2014-07-28T14:54:53.840" Score="7" Body="&lt;p&gt;One of the consequences that I find more fascinating with the increased CO&lt;sub&gt;2&lt;/sub&gt; problem is the changes that affect specific components of the environment. One example that I like is the effect on poison ivy. Researchers at Duke University (&lt;a href=&quot;http://dx.doi.org/10.1073/pnas.0602392103&quot; rel=&quot;nofollow&quot;&gt;Mohan et al., 2006&lt;/a&gt;), as part of their Free-Air CO&lt;sub&gt;2&lt;/sub&gt; Enrichment (FACE) experiment, reported a large change in poison ivy activity when they added CO&lt;sub&gt;2&lt;/sub&gt;. They claim:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;...elevated atmospheric CO&lt;sub&gt;2&lt;/sub&gt; in an intact forest ecosystem increases photosynthesis, water use efficiency, growth, and population biomass of poison ivy.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;For more information on the experiment and the many results they have obtained from it, check &lt;a href=&quot;http://www.bnl.gov/face/DukeForest-FACE.asp&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;. They have more than 250 publications on the findings of the experiment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So now, on top of all the other changes, we have to put up with poison ivy on steroids.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it is important to keep in mind that &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... species that respond strongly to elevated Carbon in [nonresource-limited] experiments are unlikely to also be the most responsive in resource-limited field conditions... [so] we cannot directly extrapolate ... which species will be most responsive to elevated Carbon in the long term.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1111/1365-2435.12102/pdf&quot; rel=&quot;nofollow&quot;&gt;Ali et al., 2013&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The rise in [CO2] will probably alter the prevalence of invasive species, but the nature of this change is difficult to predict. Whereas alien species may benefit from higher[CO2] in some regions, native species may benefit in others. Plants with certain CO2-responsive traits are likely to benefit from the rise in [CO2], especially if they are growing in ecosystems where those traits are rare. For instance, C3 species growing in C4-dominated ecosystems are likely to benefit from the rise in [CO2] (but under some circumstances may not). Invasiveness and CO2-responsiveness are not clearly linked. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://web.ics.purdue.edu/~jsdukes/Dukes_CO2_Invasion.pdf&quot; rel=&quot;nofollow&quot;&gt;Dukes, 2000&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="543" LastEditDate="2015-12-01T07:20:59.383" LastActivityDate="2015-12-01T07:20:59.383" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2300" PostTypeId="1" CreationDate="2014-07-29T03:58:09.380" Score="10" ViewCount="1663" Body="&lt;p&gt;I am familiar with the concept of cloud seeding, where precipitation can be induced with aerosols, thereby altering storm intensity further downwind.  Are there methods that could be used to drastically alter storm wind intensity or storm direction?  What technology could theoretically be developed in the future that used satellites, ocean networks, balloons, or other devices to curb strong winds (e.g. tornadoes or hurricanes) so that populated areas could be protected.  Or is a strong storm simply too large scale of an event to be altered significantly by humans?&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2020-05-11T23:52:15.390" LastActivityDate="2022-03-10T21:11:24.423" Title="How could humans alter storm intensity or direction other than cloud seeding?" Tags="|meteorology|storms|geoengineering|" AnswerCount="4" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="2301" PostTypeId="2" ParentId="2294" CreationDate="2014-07-29T04:37:38.660" Score="10" Body="&lt;p&gt;Uranium is primarily lithophilic (it readily combines chemically with oxygen), but also is chalcophilic (it readily combines chemically with sulfur). It definitely is not siderophilic (it does not readily dissolve in molten iron). The first two means that uranium compounds are easily formed, which are of course much less dense than is pure uranium. That uranium is not siderophilic means that the mechanisms that led to the differentiation of the Earth had a lesser effect on uranium than it did on metals that easily alloy with iron.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-07-29T04:37:38.660" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2302" PostTypeId="1" AcceptedAnswerId="2303" CreationDate="2014-07-31T02:31:58.643" Score="20" ViewCount="3588" Body="&lt;p&gt;At what power output would we be using so much geothermal energy that we cool the core enough to endanger the Earth's magnetic field and have to stop using it? Is this a conceivable concern for a future energy crisis?&lt;/p&gt;&#xA;" OwnerUserId="654" LastEditorUserId="124" LastEditDate="2014-08-06T04:50:05.597" LastActivityDate="2017-02-07T16:14:11.123" Title="Can the overuse of geothermal energy become an environmental concern?" Tags="|geophysics|geothermal-heat|" AnswerCount="3" CommentCount="0" ClosedDate="2017-02-08T01:41:51.810" ContentLicense="CC BY-SA 3.0" />
  <row Id="2303" PostTypeId="2" ParentId="2302" CreationDate="2014-07-31T04:27:20.843" Score="17" Body="&lt;p&gt;No, this seems highly unlikely.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to online sources:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Average human power consumption in 2008 was estimated at 15 TW. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Total annual heat loss from the Earth due to the surface heat flux is estimated at 44.2 TW. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Estimates of the electricity generating potential of geothermal energy around the world are consistently less than 2 TW.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So although the average power consumption is a surprisingly large fraction of the total geothermal heat flux, the part that might possibly be extracted for power is quite small.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are much more concerning environmental impacts to geothermal power development than freezing the core and destroying the Earth's Magnetic field. These include increased rates of release of carbon and sulfur into the atmosphere and land use issues.   &lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-07-31T04:27:20.843" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="2304" PostTypeId="2" ParentId="2294" CreationDate="2014-07-31T15:24:22.460" Score="2" Body="&lt;p&gt;Uranium does not exist as native metal and is usually combined with oxygen forming silicates, phosphates, carbonates, sulphates, arsenates, and vanadates, which are stable minerals found in the Earth's crust.  Uranium is held in the crust because of its chemistry. &lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-07-31T15:24:22.460" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2305" PostTypeId="2" ParentId="2293" CreationDate="2014-08-01T10:19:13.980" Score="7" Body="&lt;p&gt;The simple answer is no.&#xA;There are not any significant rare earth elements (REE) deposits in Iceland. This question: &lt;a href=&quot;https://earthscience.stackexchange.com/q/310/725&quot;&gt;What are rare earths and why do they cluster near alkaline magmatism?&lt;/a&gt; gives a list of possible formation mechanisms.&#xA;Basically, to form a magmatic deposit of rare earth elements, simple magmatic activity is not enough. It would have to be magmatic activity related to one of two processes (or both):&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Magma formed due to very low degree of mantle melting. REE are incompatible elements, meaning that they concentrate into the liquid during melting. If the mantle melts to a very low degree (let's say less than 1%), REEs are concentrated in it. Once the melting proceeds, the REE-rich liquid is diluted by further REE-poor melt. Rocks that form in this process are, or example, carbonatites and alkaline magmas. They do not exist in Iceland (and if they do, very scarce).&lt;/li&gt;&#xA;&lt;li&gt;Magma that has evolved and differentiated. Let's say we take the REE-poor magma from 1. Now it starts crystallising. Remember that REE are incompatible and will stay in the liquid. So the residual melt eventually gets enriched in the REE. Think salt water being evaporated - the salt remains inside the water making it more saline. Pegmatite is one type of rock that forms in this process. Similarly, it does not occur in Iceland.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-08-01T10:19:13.980" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2306" PostTypeId="2" ParentId="2290" CreationDate="2014-08-01T10:32:07.200" Score="10" Body="&lt;p&gt;I'll begin with your second question, as to how mountains erode.&#xA;To simplify things, there are two methods:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Physical weathering, where the rocks are broken down by weather. For example, there are cracks in rocks that get filled by water which freezes and expands. This maker the cracks bigger and breaks down the rock. Also wind, earthquakes and any other process that breaks it down.&lt;/li&gt;&#xA;&lt;li&gt;Chemical weathering, where the rocks are not broken by are altered to softer and weaker types of &quot;rock&quot;. For example, take granite, a common rock in mountain ranges. It contains minerals from the feldspar family which are solid and hard. However, give some time and water and they convert to minerals from the clay family (aka &quot;dust&quot;).&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The first process is more relevant for tall mountains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, how do we know the rate? This is a competition between uplift (the rising of the mountains) and the weathering (the breaking down of mountains). I'll give one example to illustrate it. Let's say that on the mountain top you find limestone with a certain fossil that you know existed 5 million years ago. So you know this used to be at the sea floor, let's say 300 meters below the water, but now it's 2000 meters up in the sky. So it had to rise 2300 meters in 5 million years. You can calculate the average uplift rate from that. Also, let's say that you know that in the past 10 years, a certain amount of rock was eroded from the mountain. You can calculate the rate of weathering. This way you can know the total rate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are new modern methods which rely on cosmogenic isotopes to get a much more accurate picture of this process, but that's for another question.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2014-11-25T09:18:06.933" LastActivityDate="2014-11-25T09:18:06.933" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2307" PostTypeId="2" ParentId="2275" CreationDate="2014-08-01T10:44:10.937" Score="7" Body="&lt;p&gt;Groundwater consists mostly of water, obviously.&#xA;Usually, &quot;minerals&quot; in water (for example in bottled water) are actually not minerals but rather dissolved ions. Strictly speaking, minerals are solids. Fluoride, then, is also a &quot;mineral&quot;, and actually a dissolved ion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Groundwater usually begin their life as precipitation: rain, melting snow, etc. These are usually clean and pure (as in distilled) waters and once they percolate through the ground they pick up ions from the rocks and from the soil.&#xA;For example, groundwater in areas rich in limestone will have high calcium contents. So yes, there are differences in different areas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Groundwater is mostly safe. However, there are cases where it isn't. Most commonly, groundwater contaminated by man-made sources. Leaks from factories, improper water treatment, etc. Also, some groundwater may be acidic (low pH) or basic (high pH, &lt;sup&gt;1&lt;/sup&gt;). While this may be desired in natural hot spas, this is not something that would be safe to drink. Groundwater may also be contaminated with &lt;a href=&quot;http://en.wikipedia.org/wiki/Arsenic_contamination_of_groundwater&quot; rel=&quot;nofollow&quot;&gt;arsenic&lt;/a&gt; or with radium &lt;sup&gt;(2)&lt;/sup&gt;, a radioactive element that occurs naturally in Uranium-bearing rocks (e.g. granite).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References from my local area:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1) Saines, M., Dickson, P., &amp;amp; Lambert, P. (1980). An occurrence of calcium hydroxide ground water in Jordan. &lt;em&gt;Groundwater&lt;/em&gt;, 18(5), 503–503. doi:&lt;a href=&quot;http://dx.doi.org/Saines,%20M.,%20Dickson,%20P.,%20&amp;amp;%20Lambert,%20P.%20(1980).%20An%20occurrence%20of%20calcium%20hydroxide%20ground%20water%20in%20Jordan.%20Groundwater,%2018(5),%20503%E2%80%93503.%20doi:10.1111/j.1745-6584.1980.tb03427.x&quot; rel=&quot;nofollow&quot;&gt;10.1111/j.1745-6584.1980.tb03427.x&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) Vengosh, A., Hirschfeld, D., Vinson, D., Dwyer, G., Raanan, H., Rimawi, O., … Ganor, J. (2009). High naturally occurring radioactivity in fossil groundwater from the Middle East. &lt;em&gt;Environmental Science &amp;amp; Technology&lt;/em&gt;, 43(6), 1769–1775. doi:&lt;a href=&quot;http://dx.doi.org/10.1021/es802969r&quot; rel=&quot;nofollow&quot;&gt;10.1021/es802969r&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2014-11-18T13:35:01.850" LastActivityDate="2014-11-18T13:35:01.850" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2308" PostTypeId="2" ParentId="2250" CreationDate="2014-08-01T10:55:15.943" Score="13" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;the mantle is in a highly reduced state&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is not entirely correct. The core is in a highly reduced state, but the mantle is not necessarily reduced, and is quite oxidised in some places. The mantle is heterogeneous.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;however I justify its emission because carbon dioxide is continually being fed into the mantle by the subduction of carbonate sediments, is this correct?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The carbon dioxide in the mantle does not necessarily derive from subduction of carbonates.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Or is this all wrong, and the gases are being emitted because they are still being degassed from the solid mantle in the process if heterogenous separation which separated the atmosphere from the mantle. If this is the case, why have all other gases been separated but not the two I have mentioned?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Not entirely accurate. Although it is true that some of the gases in the atmosphere derived from the differentiation of the core-mantle-crust system, a popular theory suggests that many of the gases came after the differentiation through other planetary bodies such as comets and meteorites. You are also implying that carbon dioxide and sulphur dioxide are the only two gases that are emitted from volcanoes. No. Water vapour is also emitted (commonly much more than the other two) and also other gases. It's just that less people care about the water and it gets less publicity, because, well, it's just water. There are other gases that are emitted as well: nitrogen, the noble gases. But they are much less common than the other two. They are not the &lt;em&gt;only&lt;/em&gt; gases.&lt;/p&gt;&#xA;&lt;p&gt;The authors of &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0012821X98000867&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fluxes and sources of volatiles discharged from Kudryavy, a subduction zone volcano, Kurile Islands&lt;/a&gt; write:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Several potential sources for CO&lt;sub&gt;2&lt;/sub&gt; can be identified: (1) hotspot-type mantle, (2) MORB-type mantle, (3) subducted oceanic crust (MORB), (4) marine carbonate, (5) organic C from crustal and subducted sediments&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;They also give a table which states that in island arc volcanoes, 12% of carbon is sourced from the mantle, 67% is sourced from carbonates and 21% is organic carbon. Note that this only gives the amount degassed from volcanoes in subduction zone arcs. This does not mean that all carbonate-hosted carbon is released from the rocks to be degassed. I read somewhere that only 50% is degassed, and the rest is lost to the deep mantle. I would also expect that MORB magmas will have significantly less carbonate-sourced carbon.&lt;/p&gt;&#xA;&lt;p&gt;Also, &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0012821X10004140&quot; rel=&quot;nofollow noreferrer&quot;&gt;The deep carbon cycle and melting in Earth's interior&lt;/a&gt;&#xA;may be of interest.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="7064" LastEditDate="2022-11-01T20:46:06.073" LastActivityDate="2022-11-01T20:46:06.073" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="2309" PostTypeId="2" ParentId="1084" CreationDate="2014-08-01T11:21:44.637" Score="11" Body="&lt;p&gt;You are correct about halite and sylvite. I might add that carnallite also has an extremely bitter taste. These three minerals are chlorides and dissolve very easily, so that may be a part of the issue here.&#xA;Differentiating mudstone (clay) from siltstone is actually not about taste, but rather about texture. Note that this can be misleading. If you have a rock with 70% clays and 30% sand (or silt), you are going to feel the silt, giving it a higher proportion in your estimate, unless you have enough experience to consider this bias.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would also like to note the dangers in tasting rocks. Although not common, some minerals are radioactive. Also some minerals contain lead, mercury and other hazardous elements. Some minerals may also be contaminated by anthropogenic pollution. So be careful with tasting rocks.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2014-08-01T11:21:44.637" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2310" PostTypeId="1" AcceptedAnswerId="2311" CreationDate="2014-08-01T12:25:55.810" Score="1" ViewCount="336" Body="&lt;p&gt;Suppose we have two stones, the first being lighter than the second. Release the two stones from a height to fall to Earth. Stone 2, being heavier than stone 1, falls more rapidly. If they are joined together, argues Galileo, then the combined object should fall at a speed somewhere between that of the light stone and that of the heavy stone since the light stone by falling more slowly will retard the speed of the heavier. But if we think of the two stones tied together as a single object, then Aristotle says it falls more rapidly than the heavy stone. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question is how do the stones know if they are one object or two?&lt;/p&gt;&#xA;" OwnerUserId="726" LastActivityDate="2014-08-01T13:36:25.640" Title="Is heavier bodies fall faster than lighter ones" Tags="|geophysics|" AnswerCount="1" CommentCount="2" ClosedDate="2014-08-01T21:24:49.797" ContentLicense="CC BY-SA 3.0" />
  <row Id="2311" PostTypeId="2" ParentId="2310" CreationDate="2014-08-01T13:36:25.640" Score="5" Body="&lt;p&gt;The two stones will accelerate at the same rate due to gravity. This is usually attributed to Galileo although it was known before that - eg. John Dee was aware of it and didn't think it a new revelation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if the two stones have the same shape and size - ie. so aerodynamic effects are identical, they will fall at the same acceleration and speed.&#xA;There are plenty of experiments to demonstrate this, but perhaps one of the most well known was by one of the Apollo astronauts (the Moon being essentially airless has no aerodynamic effects).  The result can also be derived from Newton's Inverse Square Law of Gravity and his Second Law of Motion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I were you, I would forget about Aristotle when it comes to trying to understand the world around us. He didn't have any concept of forces, inertia, and momentum as we would understand it today. His concept of forces was provably wrong with knowledge available to him at the time.&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2014-08-01T13:36:25.640" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2315" PostTypeId="2" ParentId="2230" CreationDate="2014-08-02T19:02:48.247" Score="7" Body="&lt;p&gt;First off, the purported variations were reported to be cyclical. So the net effect on archeological dating would be null even if these variations existed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly, these purported variations are very dubious. Scientists are not immune from &quot;crackpot syndrome&quot;. If anything, scientists are more susceptible to this than the average public. There's a bit of a crackpot lurking in every good scientist. Their job, their very being, is tied up in pushing the boundary of human knowledge. Very good scientists listen to their inner crackpot but keep it inside until they are very sure that their inner crackpot has revealed something new. Not so good scientists regularly expose their inner crackpot for the whole world to see.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What this means is that when you read some extraordinary claim you should be extraordinarily suspicious, at least at first. They might have found something, then again, they might just be exposing themselves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this case, I suspect the latter. What I suggest in the case of extraordinary claims: Go to a site such as scholar.google.com and search for the journal article in question. Scholar gives a citation count (oftentimes inflated, but that's a different story). Click on it and you'll get a new page that lists the articles that cited the article in question. In this case, you'll see that there have been a paltry 25 citations in the 8 years since the article was published. That alone is very noteworthy. This article that you think is significant is anything but.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you dig deeper, you'll see that almost all of those 25 citations are self-citations, subsequent articles by one or more of the original authors who have cited their own work. That makes this article even more suspicious. If you filter out the self-citations, you'll see that the original list of 25 citations dwindles down to two or three, and most of those say &quot;There's nothing to see here. Move along, move along.&quot;&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-08-02T19:02:48.247" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2317" PostTypeId="1" CreationDate="2014-08-03T16:06:13.623" Score="6" ViewCount="205" Body="&lt;p&gt;I don't know an awful lot about meteorology, so please bear with me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My wife (who has a Geography degree) told me that rain can be generated when moist air is pushed up the side of a mountain. This makes sense from a thermodynamic point of view, but I was wondering what scale we are talking about.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It so happens we live in a mountainous area, and I often see dark clouds over the other side of the mountains. The prevailing wind is always towards us, and when it rains, it looks really bad on the other side, but somewhat ordinary by the time it gets to where we live.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The lake on the far side of the mountain is at around 400 m, the mountain is a somewhat flat ridge peaking at 1100 m, and our side of the lake is at around 700 m.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is most of the water dumped on the far side from us?&lt;/p&gt;&#xA;" OwnerUserId="733" LastEditorUserId="81" LastEditDate="2014-08-03T19:31:13.070" LastActivityDate="2014-08-03T19:31:13.070" Title="Am I observing orographic rainfall?" Tags="|meteorology|precipitation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2318" PostTypeId="2" ParentId="2317" CreationDate="2014-08-03T19:16:31.250" Score="7" Body="&lt;p&gt;700 m elevation difference on the windward side will be definitely enough to trigger orographic influences on precipitation. Thus from your description it seems very plausible that the mountains influence the precipitation you get.&lt;/p&gt;&#xA;" OwnerUserId="124" LastActivityDate="2014-08-03T19:16:31.250" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2319" PostTypeId="1" AcceptedAnswerId="2320" CreationDate="2014-08-04T14:17:59.580" Score="10" ViewCount="129" Body="&lt;p&gt;Why are tropical cyclones in the Bay of Bengal more frequent and stronger than those in the Arabian Sea?&lt;/p&gt;&#xA;" OwnerUserId="735" LastEditorUserId="12549" LastEditDate="2018-08-16T08:57:11.243" LastActivityDate="2018-08-16T08:57:11.243" Title="North Indian ocean tropical cyclones" Tags="|meteorology|tropical-cyclone|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="2320" PostTypeId="2" ParentId="2319" CreationDate="2014-08-05T01:38:12.433" Score="8" Body="&lt;p&gt;During the Indian Summer Monsoon, a low level jet covers the Arabian Sea. This causes vertical wind shear to increase over the Arabian Sea and inhibits cyclogenesis in the region. Hence, less tropical cyclone activity compared to the Bay of Bengal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.meted.ucar.edu/tropical/textbook_2nd_edition/print_3.htm#page_5.3.0&quot;&gt;http://www.meted.ucar.edu/tropical/textbook_2nd_edition/print_3.htm#page_5.3.0&lt;/a&gt;&#xA;(Need account to login)&#xA;&lt;a href=&quot;http://www.nature.com/nature/journal/v479/n7371/full/nature10552.html#ref1&quot;&gt;http://www.nature.com/nature/journal/v479/n7371/full/nature10552.html#ref1&lt;/a&gt;&#xA;(First line)&lt;/p&gt;&#xA;" OwnerUserId="737" LastActivityDate="2014-08-05T01:38:12.433" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2321" PostTypeId="2" ParentId="709" CreationDate="2014-08-05T08:59:58.060" Score="5" Body="&lt;p&gt;There are some subtleties that I'd like to add, in addition to Mark's answer. When talking about the hardness of a mineral, the nature of the chemical bonds in the crystal structure (e.g. covalent vs ionic) are not the only important thing. Crystal morphology is also important.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, Si-O-Si and Al-O-Al bonds usually cause minerals to be hard, such as in the case of quartz and feldspar. However, if you look at clays and other related minerals, they also have similar bonds. In this case, however, crystal morphology is the determining factor. Clays are not one big crystal, but an aggregate of many micron-sized crystals. The hardness is not determined by formation of crystal lattice defects and dislocations as in Mark's explanation, but rather by movement of individual crystals. Assuming you could have had a single huge clay crystal, it would be much harder than the common lump of clay.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, take for example graphite. One of the reasons for its softness is the fact that each carbon ring (see &lt;a href=&quot;http://www.enmu.edu/services/museums/miles-mineral/diamond.shtml&quot;&gt;link&lt;/a&gt; for refresher) slides on top of another, and not any change in the actual bonds of the carbon atoms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Calcite is another example. With a Mohs hardness of 3, you are not supposed to be able to scratch it with your fingernail. However, &lt;a href=&quot;http://en.wikipedia.org/wiki/Chalk&quot;&gt;chalk&lt;/a&gt; is a calcite bearing rock sometimes defined as a &quot;limestone you can scratch with your fingernails&quot;. The case here is similar, individual clay-sized grains of calcite are moving around.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another point is that the Mohs' scale is sometimes too idealistic. Take for example feldspar, that has a Mohs hardness of 6. This is for a perfect crystal. However, often feldspar crystals are slightly altered to said clays, thus reducing the hardness.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An additional interesting point is that per crystal, hardness is not always a constant. Take for example the mineral &lt;a href=&quot;http://webmineral.com/data/Kyanite.shtml&quot;&gt;kyanite&lt;/a&gt;. It has a hardness of 4 in one direction and 6 to 7 in another direction.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2014-08-05T08:59:58.060" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2323" PostTypeId="1" AcceptedAnswerId="2377" CreationDate="2014-08-05T11:24:12.737" Score="13" ViewCount="276" Body="&lt;p&gt;Denitrification requires low oxygen conditions as wells as organic carbon.&#xA;Are reduced soils (e.g gleysols) more likely to have higher denitrification rates because they have low oxygen levels? &lt;/p&gt;&#xA;" OwnerUserId="721" LastEditorUserId="174" LastEditDate="2014-08-19T00:42:07.170" LastActivityDate="2014-08-22T17:09:30.527" Title="How does soil redox potential affect the rate of denitrification?" Tags="|hydrology|soil|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2324" PostTypeId="1" AcceptedAnswerId="2325" CreationDate="2014-08-05T16:14:07.813" Score="11" ViewCount="36912" Body="&lt;p&gt;Where is the current body of science learning towards, that iron came from meteor or it was somehow formed on earth?&lt;/p&gt;&#xA;" OwnerUserId="742" LastEditorUserId="4487" LastEditDate="2015-11-23T07:36:22.727" LastActivityDate="2016-11-26T02:11:01.793" Title="Which theory is stronger, that iron came from outside or was formed within earth?" Tags="|geology|geochemistry|core|meteorite|iron|" AnswerCount="5" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2325" PostTypeId="2" ParentId="2324" CreationDate="2014-08-05T17:04:25.543" Score="18" Body="&lt;p&gt;The only elements that were formed on Earth are those produced by radioactive decay. There are four natural decay chains that start with transuranic elements and none terminate in iron; neither do the decay chains that are artificial or those that result from cosmic radiation. So all of our iron is from the Earth's formation or meteor impacts since then.&lt;/p&gt;&#xA;" OwnerDisplayName="user231" LastEditorDisplayName="user231" LastEditDate="2014-08-07T15:06:12.867" LastActivityDate="2014-08-07T15:06:12.867" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="2326" PostTypeId="1" CreationDate="2014-08-05T17:23:08.533" Score="11" ViewCount="483" Body="&lt;p&gt;Merely what the title states. My knowledge of geography/geology/*logy is limited to high-school, and some snippets, and snatches of conversation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I understand Earth's magnetic field is attributed to the bi-layered nature of it's core. Proto-Earth probably did not have a magnetic field. Apparently much later Earth's core cooled enough to separate into two layers - causing the field to appear&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How long did it take for Earth's magnetic field to first appear? &#xA;As a corollary, did water appear first on Earth, OR did the magnetic field appear first?&lt;/p&gt;&#xA;" OwnerUserId="743" LastEditorUserId="124" LastEditDate="2014-08-06T05:14:56.963" LastActivityDate="2014-08-06T05:14:56.963" Title="How long did it take for Earth's magnetic field to first appear?" Tags="|geophysics|earth-history|geomagnetism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2327" PostTypeId="2" ParentId="2324" CreationDate="2014-08-06T00:06:33.797" Score="5" Body="&lt;p&gt;So (naturally occurring) elements on earth can only come to be here in three ways.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Either they are formed here via radioactive decay.&lt;br&gt;&#xA;They came via meteor.&lt;br&gt;&#xA;They were already here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As mistermarko stated above iron isn't normally formed via radioactive decay, so we're left with the last two choices.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However if we go back far enough, earth itself was a bunch of meteors and dust that clumped together to form the earth. All matter on earth came from dust, a meteor or a comet. Some of that matter has changed from one element to another, but not iron.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus all iron came via meteor. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It isn't a matter of tracing this theory through history, because we know which elements decay into other elements and none of the ones found on earth end in iron.&lt;/p&gt;&#xA;" OwnerUserId="746" LastActivityDate="2014-08-06T00:06:33.797" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2328" PostTypeId="2" ParentId="2324" CreationDate="2014-08-06T00:18:29.367" Score="6" Body="&lt;p&gt;I believe the &lt;em&gt;element&lt;/em&gt; iron (Fe) is formed by &lt;a href=&quot;http://en.wikipedia.org/wiki/Stellar_nucleosynthesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;stellar nucleosynthesis&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;stellar nucleosynthesis:&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;it's a process of continuous fusion of the star element to reach heavier and heavier elements. starting from hydrogen (H) till iron (Fe) (the heaviest element the process could reach). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each 2 atoms of light elements fuse together to form heavier element atom. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example 2 hydrogen atoms (H --&gt; 1 proton) fuse to form helium (He --&gt; 2 protons). &lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorUserId="7043" LastEditDate="2016-11-26T02:11:01.793" LastActivityDate="2016-11-26T02:11:01.793" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2329" PostTypeId="2" ParentId="2326" CreationDate="2014-08-06T00:46:09.953" Score="10" Body="&lt;p&gt;The age of the &lt;a href=&quot;http://en.wikipedia.org/wiki/Earth%27s_magnetic_field&quot;&gt;Earth's magnetic field&lt;/a&gt; could be as old as the existence of the physical conditions capable of generating a magnetic field. Because we believe the geomagnetic field originates from the liquid outer core, your question could be restated as: When did the Earth form a liquid core?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How the Earth's core formed is still not well understood and the area of research is referred to as &lt;a href=&quot;http://www.google.com/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=14&amp;amp;cad=rja&amp;amp;uact=8&amp;amp;sqi=2&amp;amp;ved=0CGUQFjAN&amp;amp;url=http%3A%2F%2Fastro.berkeley.edu%2F~gmarcy%2Fastro160%2Fpapers%2FFormation_of_rocky_planets.pdf&amp;amp;ei=gXnhU6uNM4PooAS0zIC4Dg&amp;amp;usg=AFQjCNGVJ2yeuS7ejUCfKbOY4-mqRIWFnw&quot;&gt;planetary differentiation&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-08-06T00:46:09.953" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2331" PostTypeId="2" ParentId="2324" CreationDate="2014-08-06T04:23:55.233" Score="11" Body="&lt;p&gt;All the material that eventually formed our solar system is essentially recycled star dust.   All iron on Earth was produced by large stars that existed before our Sun formed: the iron was created during nuclear fusion and later released when the parent star(s) exploded, presumably supernova.  After our solar nebula had formed and material had been gravitationally compacted, dense elements like iron did not get far from the center of the nebula before &quot;precipitating&quot; out into planets and meteors.  Thus the inner solar system has a high abundance of iron. This is in contrast to low-density elements/molecules that were in general able to escape the center of the nebula and make it pretty far before being pulled into a large mass.  So we have high iron planets and meteors close to the sun (relatively speaking), and very little iron in the &quot;gas giants&quot; part of the solar system.  I would consider this to be material that is &quot;already there&quot; but certainly some iron has been added by meteors.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2014-08-06T05:34:05.160" LastActivityDate="2014-08-06T05:34:05.160" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2333" PostTypeId="2" ParentId="2298" CreationDate="2014-08-06T09:59:47.667" Score="2" Body="&lt;p&gt;Differences in subduction geometry depend mostly on what type crust takes part in the collision (oceanic to oceanic, continent to continent, oceanic to continent), the speed of the two (or three) colliding parts and the relative movement of the two plates.&#xA;Many subduction zones share similar characteristics (like back arc compression and volcanic arc) but there are many differences too. The general geometry of a subduction zone is, in general, well understood, but there are still many questions about how, why and when, mostly because most of our measurements are indirect and the interpretation is still problematic. You can read &lt;a href=&quot;http://www.platetectonics.com/book/index.asp&quot; rel=&quot;nofollow&quot;&gt;http://www.platetectonics.com/book/index.asp&lt;/a&gt; for a very good and simplified explanation of tectonic plate movement.&lt;/p&gt;&#xA;" OwnerUserId="749" LastActivityDate="2014-08-06T09:59:47.667" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2334" PostTypeId="1" AcceptedAnswerId="2341" CreationDate="2014-08-06T10:23:25.597" Score="3" ViewCount="1629" Body="&lt;p&gt;There are some places on Earth which holds the record of being &quot;The wettest place on Earth&quot;. On what factors these places differ from other normal places?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An example of wettest place on Earth is &lt;a href=&quot;http://en.wikipedia.org/wiki/Cherrapunji&quot; rel=&quot;nofollow&quot;&gt;Cherrapunji&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS: Normal places doesn't include deserts.&lt;/p&gt;&#xA;" OwnerUserId="78" LastEditorUserId="64" LastEditDate="2014-08-07T04:48:47.787" LastActivityDate="2014-08-07T15:08:40.227" Title="Why do some places have rain frequently?" Tags="|meteorology|precipitation|climatology|" AnswerCount="1" CommentCount="5" ClosedDate="2014-08-09T16:59:48.753" ContentLicense="CC BY-SA 3.0" />
  <row Id="2335" PostTypeId="1" CreationDate="2014-08-06T19:27:39.527" Score="1" ViewCount="165" Body="&lt;p&gt;What books are available that address the fundamental principles all processed based modelers should be aware of?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a guide, some holy grail of text books for process based simulation models? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit:&#xA;Process based, or system models such as those used to simulate ecological/biogeochemical/landscape processes. &#xA;As Naught101 mentioned: &quot;process based modelling&quot; refers to a computational-numerical mode built on a conceptual model that is mostly based on physical laws defined by empirical relationships. As opposed to a purely empirical/statistical model. &lt;/p&gt;&#xA;" OwnerUserId="383" LastEditorUserId="383" LastEditDate="2014-09-23T14:01:46.087" LastActivityDate="2014-09-23T14:01:46.087" Title="Princples of process (systems) based modeling" Tags="|untagged|" AnswerCount="1" CommentCount="9" ClosedDate="2014-09-18T20:05:19.557" ContentLicense="CC BY-SA 3.0" />
  <row Id="2336" PostTypeId="1" CreationDate="2014-08-06T20:12:32.490" Score="13" ViewCount="1631" Body="&lt;p&gt;It's quite surprising to me that there's only one beach with black sand on Hawaii (maybe not exactly one beach, but it's only a very small fraction). The concern is, if the whole Hawaii is volcanic, therefore made of frozen lava, the sand should be black everywhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suppose the true reason is that the sand on the beaches is not &quot;made of Hawaii&quot; or &quot;made in Hawaii&quot;. However, I wonder how did the white sand make it there?&lt;/p&gt;&#xA;" OwnerUserId="99" LastEditorUserId="111" LastEditDate="2014-08-08T11:45:26.580" LastActivityDate="2014-08-08T11:45:26.580" Title="How does the sand appear on Hawaiian beaches" Tags="|sedimentology|volcanoes|regional-geology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2337" PostTypeId="2" ParentId="2336" CreationDate="2014-08-07T01:33:51.010" Score="11" Body="&lt;p&gt;I think the easy answer comes from the Hawaii &lt;a href=&quot;http://www6.hawaii.gov/dlnr/occl/sand.php&quot;&gt;Department of Land and Natural Resources&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Beaches in Hawaii may be made of 'black sand' derived from the erosion of volcanic rocks, of 'white sand' made by marine organisms, or a mixture of both. On the windward side of the Big Island, for example, black sand beaches are very common. The beach at South Point is almost entirely green sand composed of olivine, a common mineral found in the volcanic rocks here in Hawaii. On the Kona coast of the Big Island and on the other islands, the beaches have a range of mixed compositions, some with a high volcanic (detrital) component, some dominated by calcareous (reef-derived) sediment. Beach and submarine sands in Kailua Bay on windward Oahu (my research area) are almost entirely composed of calcarous, reef-derived material. On average, only about 5% of the sand grains are volcanic minerals or rock fragments. Every beach is unique and has its own source and type of sediments.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They even address some of the questions regarding &quot;foreign import&quot; &lt;a href=&quot;http://hawaiideptland.custhelp.com/app/answers/detail/a_id/459/~/where-does-hawaiis-sand-come-from%3F&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-08-07T01:33:51.010" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2339" PostTypeId="2" ParentId="975" CreationDate="2014-08-07T12:20:06.823" Score="3" Body="&lt;p&gt;I have studied archaeology, not paleonthology nor geology, so most of my answer is either extrapolation of what applies on younger material or layman's five cents. Still I hope it will be useful somehow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You already mentioned the fossilization processes - this is bit distant from my field so I'm glad that you are not asking for details on them. In archaeological record, organic material can survive for centuries only under specific condition, often similar to those leading to fossilization. These conditions are one of the main factors contributing to the density of remains of ancient people and the animals and plants accompanying them, along with past human behavior.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Inhumation helps to preserve the bones, or, with specific grave construction and acidic soil, hair and even soft tissues (&lt;a href=&quot;http://en.wikipedia.org/wiki/Egtved_Girl&quot; rel=&quot;nofollow&quot;&gt;Egtved girl&lt;/a&gt; is a famous example). Anyway, animals or even plants never practiced any ceremonial burials, so this behavioral aspect is marginal for ancient fossils. Just that organisms whose habitat was more prone to fossilization are preserved more often - but this is still part of deposition and fossilization stage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Excluding the fossilization processes (which are crucial), geological stability is the factor number one (or number two, after them). The more volcanic activity, earthquake and/or erosion, the higher chance the fossils will be destroyed. As an archeologist, I had to learn at least a little on erosion, because they can destroy the artifacts we would like to find, or at least move them so that we might be confused in evaluating the context; I believe this applies even more for the millions of years of the fossils' lifespan. If I'm right (I might be wrong; this is not my field), this is not as important as the conditions for fossilization, because the erosion and other processes that might destroy or degrade the fossils are spread more evenly than the good conditions for fossilization.&lt;/p&gt;&#xA;" OwnerUserId="101" LastActivityDate="2014-08-07T12:20:06.823" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2340" PostTypeId="2" ParentId="2230" CreationDate="2014-08-07T12:42:18.603" Score="3" Body="&lt;p&gt;I've never heard of this exact type of variations, but there are &lt;a href=&quot;http://en.wikipedia.org/wiki/Radiocarbon_dating#Dating_considerations&quot; rel=&quot;nofollow noreferrer&quot;&gt;many other variables that are considered by the scientists making radiocarbon dating&lt;/a&gt;, such as:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;C-14/C-12 ratio - this leads to &lt;a href=&quot;http://en.wikipedia.org/wiki/Radiocarbon_dating#Calibration&quot; rel=&quot;nofollow noreferrer&quot;&gt;calibration&lt;/a&gt; of the dates&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;isotopic fractionation - living organisms have slightly less C-13 and C-14 ratio in comparison to the atmosphere; this ratio my vary during the year for animals eating food with different ratio of these isotopes in different seasons&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;And many others. All these effects are taken into account, and even if this discovery is not just a measurement artifact (I tend to believe &lt;a href=&quot;https://earthscience.stackexchange.com/a/2315/101&quot;&gt;David Hammen&lt;/a&gt; that it is), it wouldn't affect the dating much.&lt;/p&gt;&#xA;" OwnerUserId="101" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-08-07T12:42:18.603" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2341" PostTypeId="2" ParentId="2334" CreationDate="2014-08-07T15:08:40.227" Score="3" Body="&lt;p&gt;The factors contributing to such differences between any given 2 locations are simply too numerous to be specific. From the top of my head : Hadley cell, local topography, source of humidity upstream (oceans, lakes, ...), etc...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case you are referring (i.e. Cherrapunji), this is mostly due to a combination of Himalaya (topography forcing), Indian Ocean (source of humidity), Walker circulation and the strong tropical evaporation at those latitudes (among other things).&lt;/p&gt;&#xA;" OwnerUserId="757" LastActivityDate="2014-08-07T15:08:40.227" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2342" PostTypeId="1" AcceptedAnswerId="2343" CreationDate="2014-08-07T15:59:27.260" Score="12" ViewCount="4167" Body="&lt;p&gt;I've always understood that basalt is an extrusive rock (formed by eruption), and dikes are intrusions (no eruption), so I would have thought that a dike could not be composed of basalt rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's come to my attention that many people talk about &quot;basalt dikes&quot; in geology, and many websites, including pages of university geology departments, talk about dikes that are basalt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The concept of a &quot;basaltic dike&quot; (note the &quot;ic&quot;) makes sense to me: a gabbro or diabase dike whose parental magma had a basaltic composition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, I know that basaltic dikes exist, but I'd like to have confirmation that there is no such thing as a dike which is basalt rock.&lt;/p&gt;&#xA;" OwnerUserId="63" LastEditorUserId="63" LastEditDate="2014-08-07T17:43:22.550" LastActivityDate="2014-12-11T07:49:33.197" Title="Is there such a thing as a &quot;basalt dike&quot;?" Tags="|petrology|igneous|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2343" PostTypeId="2" ParentId="2342" CreationDate="2014-08-07T16:26:18.980" Score="12" Body="&lt;p&gt;&quot;Basalt&quot; per definition is a fine grained rock (that is, you can't see the individual crystals with the naked eye, aka aphanitic) with a certain chemical composition. The coarse grained form of this rock is called a &quot;gabbro&quot;. A diabase (or dolerite) is something in between, but let's ignore it for the meanwhile for the sake of simplicity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So quoting from your question:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I've always understood that basalt is an extrusive rock (formed by&#xA;  eruption), and dikes are intrusions (no eruption)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is not entirely accurate. Assuming that we are talking about rocks of this specific composition, then every extrusive rock is a basalt but not every intrusive rock is a gabbro (or diabase). Fine grained rocks, and basalts in our case, can also form in hypabyssal settings (underground, for example dykes) if conditions are favourable for very quick nucleation. When a magma of 1100 °C intrudes a 20 °C surface or 100 °C rocks several hundred metres deep, the cooling rate is not too different, causing similar fine grained textures in the rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The concept of &quot;basaltic&quot; may differ in context. For example, people commonly use basaltic when the rock is similar to the &lt;em&gt;sensu stricto&lt;/em&gt; composition of basalt/gabbro, but not quite. It does not necessarily mean that we are talking about a gabbro with a composition similar to basalt. In a wider context, it may refer to &quot;basaltic&quot; vs &quot;granitic&quot; compositions, whereby their coarse and fine grained forms are called &quot;gabbro&quot; and &quot;rhyolite&quot;, respectively. No idea why this terminology is rooted like that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll finish with a photograph of a basalt dyke that I took some years ago:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/vvM74.jpg&quot; alt=&quot;The Black Heart Dyke&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2014-12-11T07:49:33.197" LastActivityDate="2014-12-11T07:49:33.197" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2344" PostTypeId="2" ParentId="2140" CreationDate="2014-08-07T18:26:38.603" Score="6" Body="&lt;p&gt;For Europe, I'd look into this dataset : &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2008JD010201/abstract&quot;&gt;http://onlinelibrary.wiley.com/doi/10.1029/2008JD010201/abstract&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a high-resolution gridded daily dataset derived from station data. However, this is a gridded dataset (25 km resolution) aimed at validation of Global Climate Model. So, depending on your need, this might be of help or not. if this kind of dataset suits your needs, you might also consider reanalysis such as GLDAS (0.25 degree resolution).&lt;/p&gt;&#xA;" OwnerUserId="757" LastActivityDate="2014-08-07T18:26:38.603" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2346" PostTypeId="1" AcceptedAnswerId="2347" CreationDate="2014-08-08T13:14:48.773" Score="14" ViewCount="255" Body="&lt;p&gt;I took this photo on my vacation in Finland showing white stripes in the rock going different ways. How are these patterns born?&lt;img src=&quot;https://i.stack.imgur.com/z28c0.jpg&quot; alt=&quot;solid rock with patterns&quot;&gt;   &lt;/p&gt;&#xA;" OwnerUserId="763" LastEditorUserId="725" LastEditDate="2014-08-09T17:01:13.683" LastActivityDate="2014-08-09T17:01:13.683" Title="How are the patterns in solid rock born" Tags="|geology|rocks|petrology|bedrock|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2347" PostTypeId="2" ParentId="2346" CreationDate="2014-08-08T15:19:23.993" Score="12" Body="&lt;p&gt;One can only speculate based upon a photograph - however they look very much like mineralized fractures. At some time in the past this rock mass may have fractured in response to thermal or tectonic stresses. Fluid may have then penetrated relatively long distances along the fractures into the area and infiltrated shorter distances into the wall rock along small scale porosity such as cracks and grain boundaries (and also possibly diffusions.)  The fluid and rock were most likely not in chemical equilibrium when they came into contact and there were chemical reactions that produced additional minerals along the trace of the original fracture. This is probably what you see - the result of a process of fracture, mass transport, and fluid-rock chemical reaction. But a geologist would need much more information about this system (than available from one photograph) to describe the details. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seeing something like this in the field is always very exciting because it raises so many questions. Where did the fluid come from? What was the temperature? When did the rock fracture?  &lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-08-08T15:19:23.993" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2348" PostTypeId="2" ParentId="893" CreationDate="2014-08-08T17:17:34.310" Score="9" Body="&lt;p&gt;Everything.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Parametrizations&lt;/li&gt;&#xA;&lt;li&gt;Spatial (horizontal and vertical) and temporal resolution&lt;/li&gt;&#xA;&lt;li&gt;Initialization&lt;/li&gt;&#xA;&lt;li&gt;Dynamical core&lt;/li&gt;&#xA;&lt;li&gt;Handling of some complex non-linear physical processes (i.e. snow)&lt;/li&gt;&#xA;&lt;li&gt;Topography representation&lt;/li&gt;&#xA;&lt;li&gt;How the mathematical equations are numerically implemented&lt;/li&gt;&#xA;&lt;li&gt;The computer used&lt;/li&gt;&#xA;&lt;li&gt;etc...&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;These are some of the main differences between 2 given numerical weather model. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With that being said, the same model will give different results when run on a different computer (Hong et al. 2013).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hong S-Y, Koo M-S, Jang J, et al. (2013) An Evaluation of the Software System Dependency of a Global Atmospheric Model. Mon Weather Rev 141:4165–4172. doi: 10.1175/MWR-D-12-00352.1&lt;/p&gt;&#xA;" OwnerUserId="757" LastActivityDate="2014-08-08T17:17:34.310" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2349" PostTypeId="2" ParentId="2162" CreationDate="2014-08-08T17:42:49.857" Score="4" Body="&lt;p&gt;Climate projections shouldn't be seen as deterministic projection of climate. Since the earth system is non-linear (i.e. chaotic), a lot of path are possible for the next decades. In other words, the statistics of climate (i.e. trend, inter-annual variability, spatial patterns) of the next 3 decades could be closer to the 2060-2090 climate projections than the climate projection of 2020-2050. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This kind of comparison lies in the decadal prediction framework. This is an emerging science in itself. One that is far from being ready for prime time. The simulations done in the 1990s were not aimed at such timescale (decadal) prediction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I doesn't answer directly the question, but I'm merely pointing out that such comparisons might be misleading.&lt;/p&gt;&#xA;" OwnerUserId="757" LastEditorUserId="757" LastEditDate="2014-08-12T14:30:36.127" LastActivityDate="2014-08-12T14:30:36.127" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2350" PostTypeId="1" AcceptedAnswerId="2353" CreationDate="2014-08-09T16:26:08.123" Score="8" ViewCount="179" Body="&lt;p&gt;I know volcanologists study volcanoes. Is there a subdiscipline that only studies maga or lava? A magmatologist? &lt;/p&gt;&#xA;" OwnerUserId="767" LastActivityDate="2014-08-09T21:54:24.373" Title="Is there an earth science discipline, or subdiscipline, that only studies magma or lava?" Tags="|volcanology|volcanoes|magmatism|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2351" PostTypeId="1" AcceptedAnswerId="2352" CreationDate="2014-08-09T17:20:26.353" Score="12" ViewCount="392" Body="&lt;p&gt;It's been a while since this happened, so I don't have many details. About 3 years ago, we had a popup storm here in Louisville. It was completely unexpected and unpredicted. That's not the strange part though. I took at look at the radar (it was about 5:00 PM) and noticed that on a 2 hour loop, the storm appeared as if it was brewing right over the city landfill and drifting towards the north-east. That was strange. They were essentially just thunderstorms with a lot of lightning, no tornado threat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But then I zoomed out of the radar, and noticed that the same thing appeared to be happening over other nearby major cities (Cincinnati, Nashville, Indianapolis, St. Louis...). I'm not sure where the landfills are in those cities, but I'm guessing that may have been a pattern. That night was unusually muggy, like 100% humidity. The date was 7/20/2011.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.almanac.com/weather/history/zipcode/40299/2011-07-20&quot; rel=&quot;noreferrer&quot;&gt;Click here for almanac data for area on that day&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/31d2F.png&quot; alt=&quot;Luckily I found this snapshot I saved&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What could explain this phenomenon?&lt;/p&gt;&#xA;" OwnerUserId="768" LastEditorUserId="64" LastEditDate="2014-08-10T03:40:04.760" LastActivityDate="2014-08-10T03:40:04.760" Title="How can you explain this storm phenomenon?" Tags="|meteorology|convection|thunderstorm|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2352" PostTypeId="2" ParentId="2351" CreationDate="2014-08-09T20:22:23.703" Score="12" Body="&lt;p&gt;This case is an excellent example of urban-induced convection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Urban areas have very different surface and soil properties, leading to a different heat balance relative to more natural environments. At times when solar shortwave radiation forcing is high - summer time, early afternoons - urban areas act as heat islands. Sensible heat flux and outgoing longwave radiation are then increased relative to the environment. While latent heat fluxes are decreased because of lack of soil moisture and vegetation in the cities, there is enough moisture coming from the environment to trigger convective cloud formation and rainfall downwind from the urban area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to the question why did this occur in four urban areas at the seemingly similar time, it just happened so. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;See this &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/EI156.1&quot;&gt;review article&lt;/a&gt; on urban-induced convection and associated physical processes for more details.&lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2014-08-09T20:37:06.523" LastActivityDate="2014-08-09T20:37:06.523" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2353" PostTypeId="2" ParentId="2350" CreationDate="2014-08-09T21:54:24.373" Score="8" Body="&lt;p&gt;Perhaps they are called &lt;a href=&quot;http://en.wikipedia.org/wiki/Igneous_petrology&quot;&gt;Igneous Petrologists&lt;/a&gt; ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Someone who studies magma/lava flows tends to go by Geophysicist because they inherently study continuum mechanics and fluid flow. &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-08-09T21:54:24.373" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2355" PostTypeId="1" CreationDate="2014-08-10T20:16:33.240" Score="38" ViewCount="1097" Body="&lt;p&gt;I expect most of you have heard of &lt;a href=&quot;http://www.iflscience.com/environment/scientists-think-they-may-have-solved-siberian-crater-mystery&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt; by now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/QZOTx.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All the news is about whether or not they were formed by the release of methane, but it is also mysterious to me why this crater has jagged edges but smooth vertical walls. It almost looks like it has been drilled.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not a geologist but I would expect it to be rough all the way down. Can someone explain why it isn't?&lt;/p&gt;&#xA;" OwnerUserId="770" LastEditorUserId="1411" LastEditDate="2015-01-17T17:00:25.313" LastActivityDate="2016-12-26T18:03:29.027" Title="Why do the Siberian methane craters have smooth vertical walls?" Tags="|geology|methane|permafrost|" AnswerCount="4" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2356" PostTypeId="1" AcceptedAnswerId="2359" CreationDate="2014-08-11T03:49:20.420" Score="8" ViewCount="145" Body="&lt;p&gt;From &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Polar_vortex&quot; rel=&quot;noreferrer&quot;&gt;http://glossary.ametsoc.org/wiki/Polar_vortex&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;polar vortex&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;A planetary-scale mid- to high-latitude circumpolar cyclonic circulation, extending from the middle troposphere to the stratosphere. &lt;em&gt;&lt;strong&gt;The Northern Hemisphere vortex often features two centers&lt;/strong&gt;&lt;/em&gt;—one near Baffin Island and the other over northeast Siberia—with analogous circumpolar asymmetry atypical in the Southern Hemisphere. (&lt;em&gt;&lt;strong&gt;emphasis mine&lt;/strong&gt;&lt;/em&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Why does the Northern Hemisphere polar vortex often have two centers, as opposed to one for the Southern? I gather that this may have something to do with the Arctic vortex being elongated in shape, but this leads to the question of why it is elongated? Does it have something to do with the terrain features below?&lt;/p&gt;&#xA;" OwnerUserId="85" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-08-11T14:28:10.043" Title="Why does the Northern polar vortex usually have two centers?" Tags="|meteorology|atmosphere|dynamics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2357" PostTypeId="1" AcceptedAnswerId="2358" CreationDate="2014-08-11T05:46:47.073" Score="10" ViewCount="95" Body="&lt;p&gt;Consider a 2-dimensional domain with the typical x-z coordinates. Given an arbitrarily stratified flow, how can we estimate the depth varying horizontal dispersion of passive particles induced by the flow?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the moment, I am seeding the domain with passive particles throughout the entire horizontal and vertical extent of the domain. Regarding the initial particle location, I employ a structured Gaussian distribution in the horizontal direction and a linear distribution in the vertical direction. Then, given the temporally variable Eulerian velocity field, I integrate all particle trajectories with a Lagrangian particle tracking code for the desired length of time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To measure dispersion, first I calculate the Standard Deviation (sd) of the horizontal distance between the particles in the initial time ($sd(\Delta x_i)$) and the final time ($sd(\Delta x_f)$) and normalize it by its maximum absolute in the initial and final stage, respectively. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\overline{sd_1} = \frac{sd(\Delta x_i)}{max(abs(sd(\Delta x_i)))}$$&#xA;$$\overline{sd_2} = \frac{sd(\Delta x_f)}{max(abs(sd(\Delta x_f)))}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given that, I use the difference between $sd_1$ and $sd_2$ as my depth variable dispersion measure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a better/more official way of doing it (taking into account that I want to use Lagrangian particle tracking methods).&lt;/p&gt;&#xA;" OwnerUserId="200" LastActivityDate="2014-08-11T13:57:16.370" Title="How to estimate dispersion in stratified flows" Tags="|ocean|oceanography|numerical-modelling|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2358" PostTypeId="2" ParentId="2357" CreationDate="2014-08-11T13:57:16.370" Score="6" Body="&lt;p&gt;There are lots of studies considering Lagrangian dispersion. One critical aspect is the addition of random displacement to the deterministic particle track in order to consider subgrid-scale processes. Your measure of dispersion seems acceptable except for the fact that it might be dependent on the resolution of your flow field. In order to compare your dispersion with other areas or times, you might need to scale it by the horizontal diffusivity of the flow. Some studies that could be helpful are &lt;a href=&quot;http://dx.doi.org/10.1175/1520-0426(2002)019%3C1114:LAAPOC%3E2.0.CO;2&quot;&gt;Mariano et al. (2002)&lt;/a&gt;, &lt;a href=&quot;http://dx.doi.org/10.1016/j.csr.2004.09.022&quot;&gt;Proehl et al. (2005)&lt;/a&gt;, &lt;a href=&quot;http://dx.doi.org/10.1016/j.csr.2010.10.011&quot;&gt;Lynch &amp;amp; Smith (2010)&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-08-11T13:57:16.370" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2359" PostTypeId="2" ParentId="2356" CreationDate="2014-08-11T14:28:10.043" Score="4" Body="&lt;p&gt;&lt;strong&gt;Northern Hemisphere&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The spatial structure of the polar vortex is determined by the stationnary waves. Stationary waves in the northern hemisphere are primarily modulated by stationary (surprise!) forcings of the northern hemisphere : &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Topography : Rockies and Himalayan mountains&lt;/li&gt;&#xA;&lt;li&gt;Land-sea ocean heating contrast&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;This spatial pattern is mostly locked but they are slightly modulated by the seasonaly changing meridional temperature gradient and from internal chaotic processes (i.e. turbulence).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This article is a must-read and not too technical for the northern hemisphere circulation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/134GM01/summary&quot; rel=&quot;nofollow&quot;&gt;http://onlinelibrary.wiley.com/doi/10.1029/134GM01/summary&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;vs Southern Hemisphere&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you compare such forcings between the northern and southern hemisphere, there is a big difference: much less land-sea contrast and less topographic forcing in the southern ocean. Hence, a &quot;wavenumber one&quot; configuration, as compared to a &quot;wavenumber two&quot; for the northern hemisphere.&lt;/p&gt;&#xA;" OwnerUserId="757" LastActivityDate="2014-08-11T14:28:10.043" CommentCount="0" CommunityOwnedDate="2014-08-12T14:04:57.720" ContentLicense="CC BY-SA 3.0" />
  <row Id="2360" PostTypeId="1" AcceptedAnswerId="2361" CreationDate="2014-08-12T03:02:30.517" Score="27" ViewCount="80235" Body="&lt;p&gt;How do I convert specific humidity to relative humidity? What variables are needed (e.g. air temperature, pressure, etc.)?&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="543" LastEditDate="2016-01-29T08:31:08.063" LastActivityDate="2021-12-15T21:34:10.133" Title="How do I convert specific humidity to relative humidity?" Tags="|meteorology|humidity|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2361" PostTypeId="2" ParentId="2360" CreationDate="2014-08-12T04:43:07.833" Score="30" Body="&lt;p&gt;Relative humidity is just &lt;span class=&quot;math-container&quot;&gt;$e/e_s$&lt;/span&gt;, the ratio of the vapor pressure to saturation vapor pressure or &lt;span class=&quot;math-container&quot;&gt;$w/w_s$&lt;/span&gt;, the ratio of mass mixing ratios of water vapor at actual and saturation values.  If you have specific humidity, which is the mass mixing ratio of water vapor in air, defined as:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ q \equiv \dfrac{m_v}{m_v + m_d} = \dfrac{w}{w+1} \approx w$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Relative humidity can be expressed as the ratio of water vapor mixing ratio to saturation water vapor mixing ratio, &lt;span class=&quot;math-container&quot;&gt;$w/w_s$&lt;/span&gt;, where:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ w_s \equiv \dfrac{m_{vs}}{m_d} = \dfrac{e_s R_d}{R_v(p-e_s)} \approx 0.622\dfrac{e_s}{p}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;and from Clausius-Clapeyron:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ e_s(T) = e_{s0}\exp\left[\left(\dfrac{L_v(T)}{R_v}\right)\left(\dfrac{1}{T_0} -\dfrac{1}{T} \right)\right] \approx 611\exp\left(\dfrac{17.67(T-T_0)}{T-29.65}\right)$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Once you have calculated &lt;span class=&quot;math-container&quot;&gt;$w$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$w_s$&lt;/span&gt; you can obtain the relative humidity as:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ RH = 100\dfrac{w}{w_s} \approx 0.263pq\left[\exp\left(\dfrac{17.67(T-T_0)}{T-29.65}\right)\right]^{-1} $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;You could also calculate &lt;span class=&quot;math-container&quot;&gt;$RH = 100(e/e_s)$&lt;/span&gt;, but I think since you are starting with &lt;span class=&quot;math-container&quot;&gt;$q$&lt;/span&gt; it isn't as straightforward as doing it this way.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Variables used:&lt;br /&gt;&#xA;&lt;sub&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$q$&lt;/span&gt; specific humidity or the mass mixing ratio of water vapor to total air (dimensionless)&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$m_v$&lt;/span&gt; specific mass of water vapor (kg)&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$m_{vs}$&lt;/span&gt; specific mass of water vapor at equilibrium (kg)&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$m_d$&lt;/span&gt; specific mass of dry air (kg)&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$w$&lt;/span&gt; mass mixing ratio of water vapor to dry air (dimensionless)&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$w_s$&lt;/span&gt; mass mixing ratio of water vapor to dry air at equilibrium (dimensionless)&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$e_s(T)$&lt;/span&gt; saturation vapor pressure (Pa)&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$e_{s0}$&lt;/span&gt; saturation vapor pressure at &lt;span class=&quot;math-container&quot;&gt;$T_0$&lt;/span&gt; (Pa)&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$R_d$&lt;/span&gt; specific gas constant for dry air (J kg&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt; K&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt;)&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$R_v$&lt;/span&gt; specific gas constant for water vapor (J kg&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt; K&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt;)&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; pressure (Pa)&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$L_v(T)$&lt;/span&gt; specific enthalpy of vaporization (J kg&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt;)&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; temperature (K)&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$T_0$&lt;/span&gt; reference temperature (typically 273.16 K) (K)&lt;br /&gt;&#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="25057" LastEditDate="2021-12-15T21:34:10.133" LastActivityDate="2021-12-15T21:34:10.133" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="2362" PostTypeId="2" ParentId="2355" CreationDate="2014-08-12T13:48:11.723" Score="4" Body="&lt;p&gt;A friend of mine works at the Permafrost institute in Moscow and he and his colleagues generally support this idea. I think that edges were formed by falling pieces of soil and vertical walls were formed when big methane bubble that went off the deeper layers.  &lt;/p&gt;&#xA;" OwnerUserId="775" LastEditorUserId="725" LastEditDate="2014-12-11T07:56:08.233" LastActivityDate="2014-12-11T07:56:08.233" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2363" PostTypeId="2" ParentId="2335" CreationDate="2014-08-12T14:37:45.930" Score="1" Body="&lt;p&gt;I guess the only thing the modeler should know is either the mathematical equation describing the system or the statistical relationship between a predictor and a predictand. You might have &quot;access&quot; to the exact equations or you might need to fit a mathematical model onto empirical observations. Then you need to code these mathematical or statistical relationship into a software (i.e. numerical model).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fairly general. The devil will be in the details.&lt;/p&gt;&#xA;" OwnerUserId="757" LastActivityDate="2014-08-12T14:37:45.930" CommentCount="4" CommunityOwnedDate="2014-08-12T14:37:45.930" ContentLicense="CC BY-SA 3.0" />
  <row Id="2364" PostTypeId="2" ParentId="2285" CreationDate="2014-08-13T14:30:16.510" Score="10" Body="&lt;p&gt;There are two ways in which earthquakes could affect the Antarctic ice sheet, either by occurring on the Antarctic continent or by occurring elsewhere and sending tsunami-type waves towards the ice sheet/continent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seismic activity occurs all the time on Antarctica. Particularly the West-Antarctic Ice Sheet (WAIS) is located over seismically active zones although such occur under the East Antarctic Ice Sheet (EAIS) as well. In the case of WAIS, subglacial volcanoes have been inferred from geophysical measurements. It is possible that such activity but also elevated geothermal heat fluxes, typical of seismically active areas, contribute to making the subglacial thermal regime temperate (at the melting temperature). This means the ice flow can, at least partially decouple from the bed and slide causing larger ice fluxes. Such behaviour is known from WAIS but is observed to be a part of the dynamic setup of the ice sheet and does not seem to change fluxes on time frames that we can observe directly or through investigations of indirect evidence of past flow variations. In short, there is no clear evidence that seismic activity in Antarctica directly causes major changes in ice loss.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tsunamis reaching Antarctica could conceivably cause break off of larger ice bergs or larger numbers of ice bergs at the fringes of the ice sheet. Ice berg calving in Antarctica is largely through ice shelves, which are floating parts of the ice sheet. These ice shelves are part of the natural way in which the ice sheet looses mass so a momentary acceleration due to tsunami-type waves is conceivable. But, the main question will be of this momentary acceleration of calving simply causes ice that would calve anyway within some period is shed more quickly resulting in a period of quiescence as the shelf recuperates and resumes normal &quot;operations*. This is unclear because we are dealing with processes that have to be seen over long time spans. The loss of an immense ice berg, such as occasionally reported in media, may not have that much significance in the long-term.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are studies indicating larger ice fluxes out from specific outlets in Antarctica. How these may be influenced by direct or indirect seismic activity has not been investigated. Ice in glaciers and ice sheets behaves plasticly, which means it can accommodate external forcing to some extent by plastic deformation, and also elastically. As an example, lake ice may bend when waves propagate in the underlying water but can also cause breakage under certain circumstances (wave amplitude and frequency). It is hence conceivable that increased breakage can occur if circumstances are just right but it is not at all clear that such activity would cause anything but momentary acceleration of processes that would be shadowed by the longer term trends caused by climatic forcing.&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2014-08-13T14:30:16.510" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2365" PostTypeId="2" ParentId="275" CreationDate="2014-08-14T01:03:34.347" Score="4" Body="&lt;p&gt;If you can't get a macroscopic sense of lineation, try microscopic measurement  (thin sections along the supposed plane principal stresses) and transfer them in macro. &lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/0125769210&quot; rel=&quot;nofollow&quot;&gt;The Techniques of Modern Structural Geology: Strain Analyses Vol I&lt;/a&gt; would be very useful for reference.&lt;/p&gt;&#xA;" OwnerUserId="749" LastActivityDate="2014-08-14T01:03:34.347" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2366" PostTypeId="2" ParentId="1084" CreationDate="2014-08-14T02:02:45.457" Score="5" Body="&lt;p&gt;Tasting rocks is done only if we already known that tasting would give us an answer about the rock type. We do not taste siltstones or sandstones because siltstone (and mudstone too) have no visible grains. On the contrary, sandstone has visible grains of sand. In most cases, when we try to identify a rock specimen in the field the tasting part is used very little.&lt;br&gt;&#xA;The most common procedure is to lick or spit the specimen (I know is sounds a little weird), in order to see better the texture and probably to identify the minerals under sunlight. This is done only in fresh cuts, made by geological hammer. Some times, especially in carbonate rocks (limestones), we smell the sample right after cutting them, in order to detect bitumen.&lt;br&gt;&#xA;Τhe dangers in tasting rocks is not coming by the rock itself, but by possible bacteria, fungi, Echinococcus, etc, from dirt, soil around it. Avoid testing any rock you collect, because it will not add anything to identification, but if like to do it anyway, do it ONLY in fresh cuts.&lt;/p&gt;&#xA;" OwnerUserId="749" LastEditorUserId="749" LastEditDate="2014-08-14T02:15:34.523" LastActivityDate="2014-08-14T02:15:34.523" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2367" PostTypeId="5" CreationDate="2014-08-14T02:08:34.493" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-08-14T02:08:34.493" LastActivityDate="2014-08-14T02:08:34.493" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2368" PostTypeId="4" CreationDate="2014-08-14T02:08:34.493" Score="0" Body="The science comprising the study of the rocks Earth is composed of, and the processes by which they change. Some subfields of geology are petrology, mineralogy, and geophysics." OwnerUserId="-1" LastEditorUserId="20" LastEditDate="2014-08-14T20:39:45.930" LastActivityDate="2014-08-14T20:39:45.930" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2369" PostTypeId="2" ParentId="2143" CreationDate="2014-08-14T03:41:57.120" Score="8" Body="&lt;p&gt;This is a very interesting question, and one that many people have explored. It's also a very complex question, as geology is inherently complex. A complete answer would probably require you attending a semester or mores worth of structural geology lectures, so below is only a very brief introduction. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer the first part of your question, there is a general consensus that fault-throw is proportional to fault length, which can be modelled by a power-law relationship. The paper presented by Joe Kington is very useful. Another paper which may be of interest is Kolyukhin, D., and A. Torabi (2012), Statistical analysis of the relationships between faults attributes, J. Geophys. Res., 117, B05406, doi:10.1029/2011JB008880.&#xA;They show that fault throw is proportional to fault length, fault type (e.g. normal, reverse/thrust) and rheology of the rock and fault zone. So to get an understanding of the probability distribution of fault-throw, you would have to explore the effects that these variables have. I couldn't find papers that explicitly deal with fault-throw probability distribution (they mainly look at predictive models and reasons), so unfortunately cannot help in giving a precise answer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second part of your question seems to deal with ways that stress (pressure caused by whatever: tectonic plates moving around, magma moving around, things moving downslope under force of gravity, etc) is accommodated by some Earth response, generally either faulting or magma emplacement. Take a look at the Andersonian theory of faulting to get an understanding of how different stress regimes (in what direction is the prinicipal stress oriented) effect creation/reactivation of faults. This theory will give you some insight into how the Earth accommodates stresses by extending/shortening. The direction and magnitude of faults is explained by the interplay of different stress components. When you were talking about free-fall, I assume that you mean gravity, which is generally reformed as overburden stress, which is an important stress component. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Magma can accommodate stress (as well as induce it!). Take a look at examples from the East African rift system around Afar. Here the fault-throw versus length relationships mentioned above do not hold, because introduction of magma into the area reduces the need for the rock to extend/stretch in the horizontal and shorten in the vertical directions. I don't have any papers on hand, but the examples are very interesting. &lt;/p&gt;&#xA;" OwnerUserId="777" LastEditorUserId="777" LastEditDate="2014-08-14T05:19:21.543" LastActivityDate="2014-08-14T05:19:21.543" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2370" PostTypeId="2" ParentId="1001" CreationDate="2014-08-14T04:24:56.677" Score="2" Body="&lt;p&gt;Large earthquakes have also been shown to change the rate of the Earth's rotation. E.g. The &lt;a href=&quot;http://www.nasa.gov/topics/earth/features/japanquake/earth20110314.html&quot; rel=&quot;nofollow&quot;&gt;2011 earthquake off the coast of Japan&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="777" LastActivityDate="2014-08-14T04:24:56.677" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2371" PostTypeId="1" AcceptedAnswerId="2404" CreationDate="2014-08-14T20:48:49.787" Score="13" ViewCount="244" Body="&lt;p&gt;I am preparing a seismic hazard map of Seattle and I was curious about the great 7.4 magnitude earthquake that occurred in the Seattle area during 900-930 A.D. On a second note, is it possible to infer the epicenters of paleoearthquakes (earthquakes that happened more than 800 years back)? And to what confidence level?&lt;/p&gt;&#xA;" OwnerUserId="779" LastEditorUserId="124" LastEditDate="2014-08-14T21:35:32.603" LastActivityDate="2014-08-23T20:44:46.320" Title="Epicenter location of the 900-930 A.D.,7.4 Magnitude Seattle Earthquake?" Tags="|geophysics|seismology|earthquakes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2372" PostTypeId="2" ParentId="2296" CreationDate="2014-08-15T10:06:04.670" Score="5" Body="&lt;p&gt;In &lt;strong&gt;Schmidt &amp;amp; Dilcher 2007&lt;/strong&gt;, the authors were interested specifically on how amber can trap aquatic organism, so this is a specific, out-of-the-norm case study but it might give you at least on order of magnitude. Here is an extract:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Within the first day or two after initial contact with water, all&#xA;  three resin fractions were traps for limnetic organisms. The resinous&#xA;  film at the surface then dried out and broke into small&#xA;  centimeter-sized fragments, so no long-term preservation can be&#xA;  expected for this exudate. The pieces of resin hanging at the water&#xA;  surface became more and more solid within a few days because of air&#xA;  contact at their upper surface. After 1 week, these pieces were nearly&#xA;  solidified (Fig. 1 D).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And later:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In contrast, the large resin bodies on the ground did not solidify as&#xA;  long as they were covered with water. But this resin was also&#xA;  initially a trap for microorganisms before a thin hardened skin&#xA;  developed at the resin surface after 1 or 2 days in the water, which&#xA;  prevented tiny organisms from getting stuck. Nonetheless, the resin&#xA;  remained liquid inside, and therefore large arthropods that were able&#xA;  to break through this skin could become entrapped over a couple of&#xA;  weeks. [...] The resin solidified when exposed to the air in the&#xA;  laboratory or by decreasing water level in the swamp during the&#xA;  summer.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So the polymerization process to go from resin to solidified resin (copal) takes weeks. At that point, the system is already closed meaning the contained organisms correspond to that time interval.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The next step (amberification) consists of further polymerization as well as oxydation and can take several million years (&lt;strong&gt;Poinar 1992&lt;/strong&gt;). However the minimum time needed for this process is unknown.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Reference:&lt;br&gt;&#xA;Poinar Jr, 1992. &lt;a href=&quot;http://books.google.de/books?id=J72FOr6AZOEC&amp;amp;printsec=frontcover#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;nofollow&quot;&gt;Life in amber&lt;/a&gt;. Stanford University Press.&lt;br&gt;&#xA;Schmidt A. R. &amp;amp; Dilcher D. L., 2007. &lt;a href=&quot;http://dx.doi.org/10.1073/pnas.0707949104&quot; rel=&quot;nofollow&quot;&gt;Aquatic organisms as amber inclusions and examples from a modern swamp forest.&lt;/a&gt; PNAS, 104(42): 16581-16585.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-09-24T07:22:39.837" LastActivityDate="2014-09-24T07:22:39.837" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2373" PostTypeId="2" ParentId="2124" CreationDate="2014-08-17T15:32:38.210" Score="4" Body="&lt;p&gt;I understand following comment as part of your question:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Was that climate and terrain habitable by prehistoric humans?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I also assume that by &quot;interglacial periods&quot; you don't mean the last and current one, the &lt;a href=&quot;http://en.wikipedia.org/wiki/Holocene&quot; rel=&quot;nofollow&quot;&gt;Holocene&lt;/a&gt;. The next latest one is Eemian. The &lt;a href=&quot;http://en.wikipedia.org/wiki/Eemian_Stage#Sea_level&quot; rel=&quot;nofollow&quot;&gt;wikipedia&lt;/a&gt; sais on the sea level during that period:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Sea level at peak was probably 4 to 6m (13 to 20 feet) higher than&#xA;  today...&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;A 2007 study found evidence that the Greenland ice core site Dye 3 was&#xA;  glaciated during the Eemian,[7] which implies that Greenland could&#xA;  have contributed at most 2 m (6.6 ft) to sea level rise.[8][9]&#xA;  Scandinavia was an island due to the inundation of vast areas of&#xA;  northern Europe and the West Siberian Plain.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So there regions were submerged either under ice or sea and definitely not habitable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And what before? I didn't find as thorough data through a brief google search, but supposing that Homo Heidelbergensis was the first &quot;prehistoric human&quot; species, we have some 600 ky of history, with several interglatials. Continental drift is marginal during this period (few kilometers IS marginal), so no continent could have been near the North Pole during any period of that time. During interglacials, &lt;a href=&quot;http://en.wikipedia.org/wiki/File:Vostok_Petit_data.svg&quot; rel=&quot;nofollow&quot;&gt;the temperature was about the same as now, +/- 2 °C&lt;/a&gt;, and so the sea level was similar to current level. Even if some parts of Lomonosov ridge (just under North Pole) were above sea, they wouldn't be habitable for the humans of that time, at least due to ice. Paleolithic Eskymos in that areas are extremely unlikely.&lt;/p&gt;&#xA;" OwnerUserId="101" LastActivityDate="2014-08-17T15:32:38.210" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2374" PostTypeId="1" CreationDate="2014-08-17T22:17:07.467" Score="10" ViewCount="641" Body="&lt;p&gt;Why do rainbows appear to have a fixed structure when a bunch of raindrops are 1. moving, and 2. granular? &lt;/p&gt;&#xA;" OwnerUserId="783" LastEditorUserId="20" LastEditDate="2014-08-17T22:47:25.317" LastActivityDate="2014-08-18T12:23:23.657" Title="Why do rainbows appear to have a fixed structure?" Tags="|meteorology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2375" PostTypeId="2" ParentId="2374" CreationDate="2014-08-18T00:37:40.910" Score="10" Body="&lt;p&gt;In short, this is because the location of a rainbow is not dependent on water droplets. The location is only dependent on the location of the Sun and of your eyes. The visibility of the rainbow is what depends on the presence of condensed water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As each drop passes through a location that corresponds to that of the rainbow your eye will see the reflected photons originating at the Sun. Before and after the rainbow, that individual drop is not in a location that allows you to see these reflected photons. The rainbow appears stationary because it is (as long as you aren't moving) and droplets are falling through it often enough that it always appears visible. &lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2014-08-18T12:23:23.657" LastActivityDate="2014-08-18T12:23:23.657" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2377" PostTypeId="2" ParentId="2323" CreationDate="2014-08-18T18:17:03.593" Score="6" Body="&lt;p&gt;Denitrification requires anoxic conditions, organic matter, and NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gleysols are anoxic soils formed in wetlands. Waterlogged wetland soils are generally both anaerobic and high in organic matter. For a given concentration of NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;, denitrification rates should be higher in Gleysols than similar soils that are aerobic soils (because there will be less organic substrate and less anaerobic habitat).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Notably, even in aerobic soils, denitrification can occur within anaerobic microsites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;references: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Bedard-Haughn 2010. Prairie Wetland Soils in Prairie Soils and Crops Journal (&lt;a href=&quot;http://www.prairiesoilsandcrops.ca/articles/volume-3-2-print.pdf&quot; rel=&quot;nofollow&quot;&gt;pdf&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;Schlesinger and Bernhardt 2013 Biogeochemistry 3rd Edition p 205-208 &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="174" LastEditorUserId="174" LastEditDate="2014-08-22T17:09:30.527" LastActivityDate="2014-08-22T17:09:30.527" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2378" PostTypeId="1" AcceptedAnswerId="2386" CreationDate="2014-08-18T18:42:10.083" Score="8" ViewCount="155" Body="&lt;p&gt;On one hand it creates more habitat for oceanic life, on the other hand, it warms up the oceans and mixes the salt and fresh waters.&lt;/p&gt;&#xA;" OwnerUserId="785" LastEditorUserId="124" LastEditDate="2014-08-25T06:29:05.530" LastActivityDate="2014-08-25T06:29:05.530" Title="How will the rising ocean affect aquatic life?" Tags="|ocean|oceanography|global-warming|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="2379" PostTypeId="1" AcceptedAnswerId="2389" CreationDate="2014-08-18T18:48:53.317" Score="11" ViewCount="261" Body="&lt;p&gt;I have a model (Miguez et al 2008) that defines &lt;em&gt;wilting point&lt;/em&gt; as the soil water content below which there is no transpiration (from Johnson et al 1993). &lt;em&gt;Field capacity&lt;/em&gt; is defined as the volume of water that remains in wetted soil after excess has drained. Neither are truly constants for a given soil, but they are commonly used as such in modeling.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there are any generic pedotransfer functions that can be used to estimate these parameters from sand/silt/clay fractions? These estimates will be used as priors in Bayesian data assimilation, and will thus be subsequently constrained by observations of soil moisture and transpiration.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Johnson et al 1993 The Implementation and Validation of Improved Land-Surface Hydrology in an Atmospheric General Circulation Model. J. Climate (&lt;a href=&quot;http://www.engr.colostate.edu/~ramirez/ce_old/projects/Johnson_etal.pdf&quot;&gt;pdf&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;Miguez et al 2008 A semimechanistic model predicting the growth and production of the bioenergy crop Miscanthus  giganteus: description, parameterization and validation. GCB-Bioenergy (&lt;a href=&quot;https://uofi.box.com/miguez2008smm&quot;&gt;pdf&lt;/a&gt;).&lt;/li&gt;&#xA;&lt;li&gt;Wikipedia &lt;a href=&quot;http://en.wikipedia.org/wiki/Field_capacity&quot;&gt;&quot;Field Capacity&quot;&lt;/a&gt; and &lt;a href=&quot;http://en.wikipedia.org/wiki/Permanent_wilting_point&quot;&gt;&quot;Wilting Point&quot;&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="174" LastActivityDate="2014-08-19T19:18:19.300" Title="Generic pedo-transfer functions to compute field capacity and wilting point from sand/silt/clay?" Tags="|geophysics|models|soil|groundwater|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2380" PostTypeId="2" ParentId="442" CreationDate="2014-08-18T20:28:55.560" Score="5" Body="&lt;p&gt;The approach used by Alton et al 2011 is appropriate for the scope and intent of this paper - to demonstrate a weakness in the approach - but is not a comprehensive analysis of PFTs in models. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think it is useful to question the use of PFTs but incorrect to conclude that Alton et al claim PFTs are not useful. Alton et al show that albedo, net shortwave radiation, and runoff are insensitive to PFT-specific values of four parameters, but they also find that net carbon balance &lt;em&gt;is&lt;/em&gt; sensitive. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The study's conclusions are limited to the JULES model that is evaluated and the parameters that are allowed to vary (and thus be estimated by inversion). There are many different models of terrestrial ecosystem functioning, and many approaches to model parameterization. Furthermore, JULES has more than 50 parameters for each PFT, and only four were varied in this study. (This is the number of parameters set in JULES' &lt;a href=&quot;http://www.geosci-model-dev.net/7/361/2014/gmd-7-361-2014-supplement.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;fortran namelist&lt;/a&gt; under &lt;code&gt;JULES_NVEGPARM&lt;/code&gt; and &lt;code&gt;JULES_PFTPARM&lt;/code&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This study also provides examples of how inversion using what are essentially 'free' parameters (analogous to 'flat priors' in a Bayesian context) has limitations. Fig 3 shows this, since the 'retrieved' (inverse-estimated) parameters are inconsistent with direct measurements of these parameters. This is more of a limitation of the inversion approach for estimating PFT-level parameters than of the utility of PFTs as an approximation of plant physiological diversity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer your question - yes, there are alternative approaches to both model structure and parameterization. This is an active area of research (and one I am interested in). Here are some examples, in order of increasing complexity (and data and computational requirements).&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Global land surface models like JULES are necessarily more abstract (and use PFTs to represent a 'Biome'). &lt;/li&gt;&#xA;&lt;li&gt;Represent groups of individuals that belong to a particular PFT and age class (This was first done in the Ecosystem Demography model (&lt;a href=&quot;http://flux.aos.wisc.edu/~adesai/documents/macrosys_papers-ankur/modeling/Moorcroft-EcolMono-EDmodel.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Moorecroft et al 2001&lt;/a&gt;, which has both evolved to ED2 and has been integrated into NCAR's Community Land Model. &lt;/li&gt;&#xA;&lt;li&gt;Vary parameters dynamically in both space and time. For example, &lt;a href=&quot;http://www.life.illinois.edu/dietze/manuscripts/gcbb1167.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wang et al 2012&lt;/a&gt; show that varying Vcmax in (vertical) space and time improve estimates of gross primary productivity in a very simple crop model.&lt;/li&gt;&#xA;&lt;li&gt;Individual Based Models (IBM's) represent individuals explicitly. These are reviewed by DeAngelis and Mooij 2005. &lt;/li&gt;&#xA;&lt;li&gt;Using probability distributions to reflect parameter variability in the system being studied. I am not aware that this has been attempted.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;However, adding more degrees of freedom limits inference - too many unconstrained parameters make it difficult to parameterize the model, understand its output, or make general conclusions about how the world operates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Remember &quot;All models are wrong, but some are useful&quot; - George Box&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/W9jU8.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Wang et al 2012 Impact of nitrogen allocation on growth and&#xA;photosynthesis of Miscanthus (Miscanthus x giganteus). Global Change Biology - Bioenergy. &lt;a href=&quot;https://dx.doi.org/10.1111/j.1757-1707.2012.01167.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;doi:10.1111/j.1757-1707.2012.01167.x&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;P. R. Moorcroft, G. C. Hurtt, and S. W. Pacala 2001. A Method for Scaling Vegetation Dynamics: the Ecosystem Demography (ED) Model. Ecological Monographs 71:557–586. &lt;a href=&quot;http://dx.doi.org/10.1890/0012-9615(2001)071[0557:AMFSVD]2.0.CO;2&quot; rel=&quot;nofollow noreferrer&quot;&gt;doi:10.1890/0012-9615(2001)071[0557:AMFSVD]2.0.CO;2&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;DeAngelis and Mooij. 2005. Individual-Based Modeling of Ecological and Evolutionary Processes. Annual Review of Ecology, Evolution, and Systematics. &lt;a href=&quot;http://www.jstor.org/stable/30033800&quot; rel=&quot;nofollow noreferrer&quot;&gt;doi:10.1 146/annurev.ecolsys.36.1020&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="174" LastEditorUserId="174" LastEditDate="2014-08-19T14:48:59.133" LastActivityDate="2014-08-19T14:48:59.133" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2381" PostTypeId="2" ParentId="2131" CreationDate="2014-08-19T02:40:11.363" Score="3" Body="&lt;p&gt;One of several &lt;a href=&quot;http://www.marinebio.net/marinescience/02ocean/swcomposition.htm&quot; rel=&quot;nofollow&quot;&gt;pages&lt;/a&gt; would seem to indicate there are other constituents that make up a much larger percentage of seawater than nitrate, At least on average. Not to say that some areas may have higher concentrations of nitrate - though this is typically associated with anthropogenic causes. I don't think nitrates are as conservative as chloride, and given a lack of dissolved oxygen and the right mix of bacteria (&lt;a href=&quot;http://pubs.usgs.gov/fs/fs05300/&quot; rel=&quot;nofollow&quot;&gt;http://pubs.usgs.gov/fs/fs05300/&lt;/a&gt;), substantial denitrification can occur - so in areas of high nitrates, one might first look for rapid pathways for the entry of water from land that would contain such constituents rather than from seawater.&lt;/p&gt;&#xA;" OwnerUserId="786" LastActivityDate="2014-08-19T02:40:11.363" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2382" PostTypeId="2" ParentId="2275" CreationDate="2014-08-19T02:51:22.730" Score="5" Body="&lt;p&gt;as for constituents in groundwater &lt;a href=&quot;http://water.usgs.gov/nawqa/studies/public_wells/&quot;&gt;this pub&lt;/a&gt; may help, or at least point to additional information.&#xA;as for is it safe to drink - according to [estimated water use] &lt;a href=&quot;http://water.usgs.gov/edu/wups.html&quot;&gt;http://water.usgs.gov/edu/wups.html&lt;/a&gt;, approximately 34% of all public supply water comes from the ground.&lt;/p&gt;&#xA;" OwnerUserId="786" LastActivityDate="2014-08-19T02:51:22.730" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2383" PostTypeId="1" CreationDate="2014-08-19T14:24:09.803" Score="14" ViewCount="2350" Body="&lt;p&gt;Why are there more intense earthquakes in Iran than in Iraq, if they are so close together?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I often hear news items of earthquakes in Iran that are higher on the Richter Scale than those that happen in Iraq.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there maybe more earthquakes in Iraq with lower magnitudes, while less earthquakes in Iran with higher magnitudes? &lt;/p&gt;&#xA;" OwnerUserId="783" LastEditorUserId="6129" LastEditDate="2021-03-30T18:57:20.613" LastActivityDate="2021-03-30T18:57:20.613" Title="Why are there more intense earthquakes in Iran than in Iraq?" Tags="|geology|geophysics|earthquakes|seismology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2384" PostTypeId="2" ParentId="2383" CreationDate="2014-08-19T14:47:39.453" Score="15" Body="&lt;p&gt;These two images probably explain it best:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Hymh5.jpg&quot; alt=&quot;Earthquakes in the middle east&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a map from the &lt;a href=&quot;http://earthquake.usgs.gov/earthquakes/world/middle_east/seismicity.php&quot; rel=&quot;noreferrer&quot;&gt;US Geological Survey Earthquake Hazards Program&lt;/a&gt;, which shows all recorded large earthquakes in the region from 1900 to March 2012.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The black lines are tectonic plate boundaries. The plate in the middle is the Arabian Plate. The current movement of that plate is show in this image from &lt;a href=&quot;http://commons.wikimedia.org/wiki/File:Arabian_Plate_map-uni.png&quot; rel=&quot;noreferrer&quot;&gt;mediawiki&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/zop83.png&quot; alt=&quot;Current movement of the Arabian Plate&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the Arabian plate is currently pushing north against the Eurasian plate, and sliding under it, causing uplift in Iran, and probably causing various &lt;a href=&quot;http://en.wikipedia.org/wiki/Earthquakes#Earthquake_fault_types&quot; rel=&quot;noreferrer&quot;&gt;slip and thrust fault lines&lt;/a&gt;. The pressure on those fault lines is released as earthquakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Iraq is not so affected, because it is on the plate. Maybe it will be in a few hundred thousand years :)&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2014-08-19T14:47:39.453" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2385" PostTypeId="2" ParentId="2360" CreationDate="2014-08-19T14:57:38.447" Score="19" Body="&lt;p&gt;Here is an implementation that I wrote in R (with documentation in the header). In addition to laboriously working through a few textbooks and online references, I have compared the results to a &lt;a href=&quot;https://www.google.com/#q=psychrometric+chart&quot;&gt;psychrometric chart&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you have likely noticed, it is a challenge to keep these terms and units straight - I wish I had @casey`s answer then! &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;##' Convert specific humidity to relative humidity&#xA;##'&#xA;##' converting specific humidity into relative humidity&#xA;##' NCEP surface flux data does not have RH&#xA;##' from Bolton 1980 The computation of Equivalent Potential Temperature &#xA;##' \url{http://www.eol.ucar.edu/projects/ceop/dm/documents/refdata_report/eqns.html}&#xA;##' @title qair2rh&#xA;##' @param qair specific humidity, dimensionless (e.g. kg/kg) ratio of water mass / total air mass&#xA;##' @param temp degrees C&#xA;##' @param press pressure in mb&#xA;##' @return rh relative humidity, ratio of actual water mixing ratio to saturation mixing ratio&#xA;##' @export&#xA;##' @author David LeBauer&#xA;qair2rh &amp;lt;- function(qair, temp, press = 1013.25){&#xA;    es &amp;lt;-  6.112 * exp((17.67 * temp)/(temp + 243.5))&#xA;    e &amp;lt;- qair * press / (0.378 * qair + 0.622)&#xA;    rh &amp;lt;- e / es&#xA;    rh[rh &amp;gt; 1] &amp;lt;- 1&#xA;    rh[rh &amp;lt; 0] &amp;lt;- 0&#xA;    return(rh)&#xA;}&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Similar variable conversion functions can be found in the &lt;a href=&quot;https://github.com/PecanProject/pecan/blob/master/modules/data.atmosphere/R/metutils.R&quot;&gt;&lt;code&gt;metutils.R&lt;/code&gt;&lt;/a&gt; file in the PEcAn data.atmosphere library. &lt;/p&gt;&#xA;" OwnerUserId="174" LastActivityDate="2014-08-19T14:57:38.447" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2386" PostTypeId="2" ParentId="2378" CreationDate="2014-08-19T16:08:03.140" Score="10" Body="&lt;p&gt;Biological communities (ecosystems) commonly change along topographic (bathymetric) slope - because conditions change along the slope. For example, there will be a temperature gradient with elevation along the side of a mountain, and gradients of temperature and the amount of incident sunlight reaching the sea floor just offshore. When climate changes, this can shift conditions up or down the slope.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The organisms of an ecosystem must be able to colonize any &quot;new habit&quot; that may be created by climate change in order to take advantage of it.  If conditions shift too quickly for the species to adapt by migration along slope, species may become extinct before they can become established in another area. For example, consider coral reefs, which are dependent upon depth, if sea-level rises too quickly, the population of surviving corals may become too small to successfully colonize reefs in new areas. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer to your question is complex. If you search the web for the term &lt;a href=&quot;http://www.sciencemag.org/content/334/6056/652.abstract?sid=73ed2d2a-f599-4334-9b58-c7a88243db26&quot;&gt;velocity of climate change&lt;/a&gt; you will find that your question is being actively researched by scientists. &lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-08-19T16:08:03.140" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2387" PostTypeId="1" AcceptedAnswerId="2388" CreationDate="2014-08-19T18:09:42.057" Score="16" ViewCount="566" Body="&lt;p&gt;From my understanding Yellowstone is a massive super-volcano, so why isn't it active? Where has its (correct me if I'm using the wrong term) hot-spot gone? Can it still erupt?&lt;/p&gt;&#xA;" OwnerUserId="785" LastEditorUserId="32" LastEditDate="2014-08-19T18:29:21.783" LastActivityDate="2014-12-12T07:07:03.337" Title="Why won't Yellowstone explode?" Tags="|geophysics|volcanology|geodynamics|geochemistry|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2388" PostTypeId="2" ParentId="2387" CreationDate="2014-08-19T18:29:05.607" Score="16" Body="&lt;p&gt;This is a complex question, and I cannot give you a complete answer I'd like to point out that there is a very important &lt;a href=&quot;http://www.nature.com/nature/journal/v506/n7489/full/nature12991.html&quot;&gt;article&lt;/a&gt; published in February of this year on the subject: volcanoes are in an eruptable state very very short periods of time in the geologic timescale; the mobilization of magma is very rapid but its storage is kept near, but under the solidus (where rock melts). Surely there will be more studies on this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the reservoir of Yellowstone is very large, the chances of having enough eruptable magma to cause Yellowstone to detonate is low, hence why its eruptions are on the time scale of hundreds of thousands of years (very small in terms of geologic time). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second thing I would like to address is &quot;Hot Spot&quot;. The Yellowstone super volcano is supplied by the &lt;a href=&quot;http://www.nature.com/nature/journal/v482/n7385/full/nature10749.html?WT.ec_id=NATURE-20120216&quot;&gt;bifurcation of the Farallon slab&lt;/a&gt; as it subducts underneath the North American plate. This bifurcation causes the separated plate to sink displacing hot mantle upwards to the surface causing volcanism (Yellowstone). There isn't a clear definition of what scientists want to call it, often suggested to be a Plume or Hot Spot. It is not migrating. Yellowstone will eventually erupt. It is still &lt;strong&gt;Active&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sorry I could not give you a &lt;em&gt;better&lt;/em&gt; answer, but hopefully this illustrates some ideas that might explain why Yellowstone has a long eruption cycle compared to smaller volcanoes. &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="725" LastEditDate="2014-12-12T07:07:03.337" LastActivityDate="2014-12-12T07:07:03.337" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2389" PostTypeId="2" ParentId="2379" CreationDate="2014-08-19T19:18:19.300" Score="7" Body="&lt;p&gt;As far as I know, there’s no one definitive pedo-transfer function (PTF) but there have been several studies that train functions against multi-site databases, rather than just deriving site-specific functions.  These PTFs typically define soil moisture-conductivity-suction relationships based on silt, sand and clay fractions from which you can read off field capacity (suction = -10 kPa) and wilting point (suction = -1500 kPa).  Which PTF you use will depend on the soil moisture-conductivity-suction hydraulic description that your model uses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For &lt;a href=&quot;http://dx.doi.org/10.1029/WR014i004p00601&quot;&gt;Clapp and Hornberger&lt;/a&gt; hydraulics there's the &lt;a href=&quot;http://dx.doi.org/10.1029/WR020i006p00682&quot;&gt;Cosby et al (1984)&lt;/a&gt; PTF.  This is trained on data from the US.  It's quite possible that there are more recent PTFs trained on more and better data, but this one is still in use (e.g., by the UK Met Office).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For &lt;a href=&quot;http://dx.doi.org/10.2136/sssaj1980.03615995004400050002x&quot;&gt;van Genuchten&lt;/a&gt; hydraulics there's the &lt;a href=&quot;http://dx.doi.org/10.1016/S0016-7061(98)00132-3&quot;&gt;Wosten et al (1999)&lt;/a&gt; PTF (see also &lt;a href=&quot;http://dx.doi.org/10.1016/S0022-1694(01)00464-4&quot;&gt;Wosten et al, 2001&lt;/a&gt;).  This is trained on the European HYPRES database, and you need organic percentage and bulk density in addition to the silt/sand/clay percentages.  There’s also &lt;a href=&quot;http://cals.arizona.edu/research/rosetta/rosetta.html&quot;&gt;ROSETTA&lt;/a&gt; (&lt;a href=&quot;http://dx.doi.org/10.1016/S0022-1694(01)00466-8&quot;&gt;Schaap et al, 2001&lt;/a&gt;), which uses several PTFs hierarchically and is trained on data from North America and Europe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that these hydraulic properties are difficult to measure in situ and in the lab, so the fitted PTFs often explain quite a low fraction of the variance in the training data.  You might be able to use this information to inform your priors, which should probably be quite conservative.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2014-08-19T19:18:19.300" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2391" PostTypeId="1" AcceptedAnswerId="2418" CreationDate="2014-08-21T06:15:39.133" Score="12" ViewCount="609" Body="&lt;p&gt;From &lt;a href=&quot;http://en.wikipedia.org/wiki/Old_Faithful&quot;&gt;wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;With a margin of error of 10 minutes, Old Faithful will erupt 65 minutes after an eruption lasting less than 2.5 minutes or 91 minutes after an eruption lasting more than 2.5 minutes. The reliability of Old Faithful can be attributed to the fact that it is not connected to any other thermal features of the Upper Geyser Basin&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Relatively &lt;a href=&quot;http://blogs.agu.org/geospace/2013/04/12/newfound-chamber-below-old-faithful-may-drive-eruptions/&quot;&gt;recent discoveries&lt;/a&gt; led scientists to believe that there is a substantial underground chamber where the water and steam build up:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A previously unknown underground cavity might help trigger the timely eruptions of the famous Yellowstone geyser Old Faithful, a new study shows. The researchers who uncovered new evidence of a chamber suspect that it stores the pressurized near-boiling water, steam, and other gases that propel Old Faithful’s eruptions.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Are the 65 minute and 91 minute values given for the eruption times simply a byproduct of needing more time for the steam to &quot;recharge&quot; after a larger eruption, or is there a deeper interplay between the underground cavity and the main channel that causes some sort of a vortex that has a (somewhat) regular periodicity?&lt;/p&gt;&#xA;" OwnerUserId="19" LastEditorUserId="32" LastEditDate="2014-08-21T15:29:04.417" LastActivityDate="2014-08-28T18:10:55.860" Title="Is the cause of Old Faithful's bimodal distribution for eruption times straightforward?" Tags="|geophysics|hydrology|geysers|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2392" PostTypeId="1" AcceptedAnswerId="2396" CreationDate="2014-08-21T06:47:27.917" Score="24" ViewCount="19462" Body="&lt;p&gt;In the movie &lt;em&gt;Into the Storm (2014)&lt;/em&gt; near the end, storm chaser Pete sees the eye of a massive tornado.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In 1928 (real life), Will Keller was in his barn when a huge tornado passed through. He reported seeing an opening in the center of the tornado &quot;about 55 feet (17 meters) across and extended some 2,500 feet (762 meters) up.&quot; &lt;a href=&quot;http://superbeefy.com/do-tornadoes-have-eyes-and-what-happens-at-the-center-of-a-tornado/&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any &quot;official&quot; documentation or evidence that tornadoes, especially stronger ones, have eyes like a hurricane does? Or is it just an urban legend?&lt;/p&gt;&#xA;" OwnerUserId="792" LastEditorUserId="792" LastEditDate="2014-11-14T07:48:00.767" LastActivityDate="2020-01-23T10:31:58.510" Title="Do tornadoes have eyes?" Tags="|meteorology|tornado|thunderstorm|severe-weather|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2393" PostTypeId="1" AcceptedAnswerId="2397" CreationDate="2014-08-21T09:03:23.443" Score="18" ViewCount="46856" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/L8wJ9.jpg&quot; alt=&quot;Earth Mineral Map&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the map above you can find that most elements are spread evenly throughout Earth's crust and that they are available all around the Earth. However, gold can only be found in certain areas of the planet such as Australia and Canada. Is there a specific reason to why gold can only be mined at these locations or is it just a coincidence?&lt;/p&gt;&#xA;" OwnerUserId="793" LastEditorUserId="20" LastEditDate="2015-07-11T14:21:39.233" LastActivityDate="2022-03-24T16:08:38.697" Title="Why do gold deposits form only in certain areas of the earth?" Tags="|petrology|mineralogy|minerals|economic-geology|" AnswerCount="5" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2394" PostTypeId="1" AcceptedAnswerId="2406" CreationDate="2014-08-21T15:27:55.063" Score="12" ViewCount="337" Body="&lt;p&gt;Coal is still a major source of energy for generation of electricity. So how much energy is used to extract a unit (tonne/kilogram etc) of coal? And thus what is the efficiency of coal as a source of energy?&lt;/p&gt;&#xA;" OwnerUserId="795" LastEditorUserId="6129" LastEditDate="2020-05-08T06:11:51.253" LastActivityDate="2020-05-08T06:11:51.253" Title="How many joules are required to mine a unit of coal?" Tags="|mining|economic-geology|coal|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2396" PostTypeId="2" ParentId="2392" CreationDate="2014-08-22T04:18:37.993" Score="20" Body="&lt;p&gt;Yes, if one takes the common meaning of the term &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Eye&quot;&gt;&quot;eye of the storm&quot;&lt;/a&gt; to be the area of relatively low wind speed near the center of the vortex, most tornadoes can be said to have eyes. Cyclostrophic balance describes a steady-state, inviscid flow with neglected Coriolis force:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\dfrac{v^2}{r} = -\dfrac{1}{\rho}\dfrac{\partial p}{\partial n}&#xA;$$  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;where centripetal force balances radial pressure gradient. Here, $v$ is tangential wind speed, $r$ distance from vortex center, $\rho$ is air density, $p$ is atmospheric pressure and $n$ is the radial direction pointing inward. From here, tangential wind speed is simply:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;v = \sqrt{-\dfrac{r}{\rho}\dfrac{\partial p}{\partial n}}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;suggesting that $v\to0$ when $r\to0$. While the flow in tornadoes is highly non-stationary and subject to friction, this idealized model shows why there must exist an &quot;eye&quot; inside a vortex or an area of closed circulation. This &quot;eye&quot; may or may not be easily recognized by a hypothetical human observer inside a tornado.&lt;/p&gt;&#xA;" OwnerUserId="192" LastActivityDate="2014-08-22T04:18:37.993" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2397" PostTypeId="2" ParentId="2393" CreationDate="2014-08-22T11:17:19.020" Score="20" Body="&lt;p&gt;I'll take the form of the question given by another person here and attempt to provide a different answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what you are asking is: &lt;strong&gt;&lt;em&gt;&quot;How did gold become so concentrated in certain parts of the world?&quot;&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So yes, gold is all around but the concentration is too low to make extraction of it worthwhile. You need some process to take small amounts of gold from a large volume and turn it into large amounts of gold in a small volume where it is convenient to build a mining facility and get it from the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the most common process to concentrate gold is through the action of hydrothermal fluids. This is basically heated water flowing through the Earth's crust. Heated water with certain properties such as acidity (pH) or dissolved anions (think chlorine-rich seawater is more corrosive than your tap water) can dissolve solid gold and put it into solution. Just like regular water can dissolve table-salt or sugar and put it into solution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So you have this hydrothermal fluid flowing through huge masses of rock (mountain-like, but underground) for a very long time, and when it goes up to the surface, it is channelled into thin conduits of fluid flow. During their ascent the conditions change (be it temperature or pH, etc.) and the water are not capable of carrying gold with them anymore. This results in the deposition of gold in that specific region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I made an example, that I hope will help you understand this in a clearer way:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/dkxXX.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in here you have rain water, entering the Earth in a large area and getting hotter as they descend down. It becomes possible for them to dissolve the gold from the large volume of rock.  But also, because the water (now steam or a supercritical fluid) are hot they start to ascend upwards, usually through a narrow zone. When they cool down again, gold forms as a solid. For example, gold associated with quartz veins commonly forms through this process.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, what happens if these gold-bearing quartz veins are exposed on the surface? They may erode by rain and snow and get concentrated in river beds. So you can either mine the original quartz vein or the nearby river bed.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2014-08-22T11:17:19.020" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2398" PostTypeId="1" AcceptedAnswerId="2399" CreationDate="2014-08-22T20:08:58.173" Score="15" ViewCount="1533" Body="&lt;p&gt;I always wondered, because helium gas is so lightweight, how did it get into the deposits like the ones that people tap? Is it formed underground, or was it trapped?&lt;/p&gt;&#xA;" OwnerUserId="611" LastActivityDate="2024-03-03T23:36:14.490" Title="How did helium deposits form?" Tags="|earth-history|gas|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2399" PostTypeId="2" ParentId="2398" CreationDate="2014-08-23T00:33:21.420" Score="20" Body="&lt;p&gt;Helium (He) is formed by radioactive decay of uranium (U) and thorium (Th) to lead (Pb).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's another name for the nucleus of a &lt;sup&gt;4&lt;/sup&gt;He atom: It's an alpha particle. Alpha decay is one of the pathways by which radioactive elements eventually decay into non-radioactive elements. For example, &lt;sup&gt;238&lt;/sup&gt;U decays to &lt;sup&gt;234&lt;/sup&gt;Th via alpha decay. There are three key isotopes that lead to the generation of helium: &lt;sup&gt;238&lt;/sup&gt;U, &lt;sup&gt;235&lt;/sup&gt;U, and &lt;sup&gt;232&lt;/sup&gt;Th. Each of these is a &quot;primordial&quot; radioactive isotope. they were present when the Earth formed, and their half-lives are sufficiently long so that a good fraction of that original content has not yet decayed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So how much helium does the decay of these isotopes produce?&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;sup&gt;238&lt;/sup&gt;U eventually decays to &lt;sup&gt;206&lt;/sup&gt;Pb via the uranium decay series (aka radium series). This decay process ultimately produces eight alpha particles.&lt;/li&gt;&#xA;&lt;li&gt;&lt;sup&gt;235&lt;/sup&gt;U eventually decays to &lt;sup&gt;207&lt;/sup&gt;Pb via the actinium decay series. This decay process. This decay process ultimately produces seven alpha particles.&lt;/li&gt;&#xA;&lt;li&gt;&lt;sup&gt;232&lt;/sup&gt;Th eventually decays to &lt;sup&gt;208&lt;/sup&gt;Pb via the thorium decay series. This process ultimately produces six alpha particles.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;After the alpha decay, the parent nuclide suddenly has an excess of two electrons orbiting it. The alpha particle has a deficit of two electrons. The alpha particle quickly grabs those two excess electrons and becomes a helium atom.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of the helium deposits in the Earth are thought to be the result of alpha decay. For example, see &lt;a href=&quot;http://www.helium-corp.com/facts/heliumfound.html&quot;&gt;Helium Facts: Where Helium is Found&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="725" LastEditDate="2014-12-12T07:15:10.863" LastActivityDate="2014-12-12T07:15:10.863" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2400" PostTypeId="1" AcceptedAnswerId="2495" CreationDate="2014-08-23T03:03:00.850" Score="11" ViewCount="290" Body="&lt;p&gt;From [1]:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The main characteristics of volcanic tremor depend strongly on&#xA;whether a volcano is erupting explosively and on the intensity of the&#xA;event. Long before an eruption, tremor is ‘narrow-band’ (about&#xA;0.5–2 Hz and sometimes monochromatic or harmonic). On transitions&#xA;to active volcanism, however, the maximum frequency can climb&#xA;to 5–7 Hz (refs 1–4) (Fig. 1c and d). Moreover, whereas tremor related&#xA;to low-intensity volcanism remains narrow-band, tremor associated&#xA;with intermittent or protracted explosive behaviour is ‘broadband’,&#xA;characterized by power distributed over the full 0.5–7 Hz tremor&#xA;bandwidth.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;When I read the above, I was not surprised that the tremors associated with volcanic activity were mainly comprised of low frequency components.  What did surprise me was that there isn't more high frequency energy present in the measurements.&lt;/p&gt;&#xA;&lt;p&gt;Is there a noticiable amount of high frequency activity in these tremors that is not significant enough to report, or are the higher frequency components absorbed by the crust surrounding the volcano?&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Jellinek, A.M. and Bercovici, D. (2011).  Seismic tremors and magma wagging during&#xA;explosive volcanism.  &lt;em&gt;Nature, 470&lt;/em&gt;, 522-526. &lt;a href=&quot;http://dx.doi.org/10.1038/nature09828&quot; rel=&quot;noreferrer&quot;&gt;[DOI]&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="19" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-09-16T11:29:21.837" Title="What happens to the higher frequency content of the tremors associated with a volcanic eruption?" Tags="|geophysics|measurements|volcanology|volcanoes|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2401" PostTypeId="1" AcceptedAnswerId="2403" CreationDate="2014-08-23T17:27:53.173" Score="12" ViewCount="3373" Body="&lt;p&gt;How exactly do we define wind velocity?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously, I suppose this is something like &quot;speed of displacement of a quantity of air&quot;, but this seems to be too imprecise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, a cup anemometer measures this velocity, but any anemometer depends on a calibration function that depends on size of cups, material used, and so on. So how do we know this function?&lt;/p&gt;&#xA;" OwnerUserId="802" LastEditorUserId="111" LastEditDate="2014-08-23T18:11:37.920" LastActivityDate="2019-08-02T20:28:53.187" Title="What exactly is wind velocity" Tags="|measurements|wind|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2402" PostTypeId="2" ParentId="2401" CreationDate="2014-08-23T18:10:28.850" Score="12" Body="&lt;p&gt;Before defining wind velocity, I think it is necessary to explain the &lt;a href=&quot;http://en.wikipedia.org/wiki/Continuum_mechanics&quot;&gt;continuum assumption&lt;/a&gt;. The basic idea is that even though gases are composed of discrete molecules occupying a small fraction of the total volume filled by the gas, gas flows are made up of many individual collisions between gas molecules. In most applications, the flow field is assumed to behave as a continuum and the discrete molecular nature of gases is ignored. By doing so, fluid properties (e.g., density, velocity) can be defined anywhere in the flow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order for the continuum assumption to be appropriate, the length scale of the application must be much larger than the mean gas particle path length. In most atmospheric conditions, including in anemometers, the mean path length is on the order of micrometers, while the anemometer size is much larger. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;While most anemometers (cup, vane, laser, acoustic resonance) measure wind speed some measure the wind's pressure (e.g., tube, plate anemometers). In the case of cup anemometer, like any other measuring device, there is an error associated with the measurement that depends primarily on the cup size. In general, the anemometer factor (the ratio of wind speed to the rotation speed of the cups) has a value between two and a bit more than three and it depends on the size of the cups and arms.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-08-23T18:10:28.850" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2403" PostTypeId="2" ParentId="2401" CreationDate="2014-08-23T19:24:47.660" Score="10" Body="&lt;p&gt;You can calibrate anemometers from other anemometers, or loosely from a windsock if precision isn't that important.  But per your question, how was the first anemometer calibrated?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/541/where-does-wind-come-from/542#542&quot;&gt;See my answer&lt;/a&gt; about wind and you'll see that we have equations that relate fluid velocity to factors like pressure gradients, friction, coriolis force, advection, etc.  We could control for these and neglect everything except the pressure gradient within a wind tunnel, and in this wind tunnel with known pressure differences we could derive the flow velocity at the anemometer and thus calibrate it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could use the same equations to determine the forces on an anemometers cups and derive or model the relation to flow velocity directly.  At some point you'd probably like the wind tunnel to empirically verify the model though or at least another known good anemometer.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-08-23T19:24:47.660" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2404" PostTypeId="2" ParentId="2371" CreationDate="2014-08-23T20:44:46.320" Score="4" Body="&lt;p&gt;If the quake you describe was on the Seattle Fault, you can probably guess the start point and the end point of the fault movement based just on the magnitude of the quake.  (Quakes that &quot;snap&quot; longer portions of the fault release more energy.)  The start point will give you the epicenter location.&lt;/p&gt;&#xA;" OwnerUserId="803" LastActivityDate="2014-08-23T20:44:46.320" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2406" PostTypeId="2" ParentId="2394" CreationDate="2014-08-24T14:34:54.217" Score="12" Body="&lt;p&gt;The efficiency of coal as a source of electricity is very low: typically of the order of 30%. So losses are of the order of 70%. But losses due to energy expended in the extraction of the coal itself only form a very small proportion of this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Estimates for extractive losses tend to be &lt;a href=&quot;http://dx.doi.org/10.3390/su3101796&quot;&gt;of the order of 0.5-5%&lt;/a&gt;. That's a huge relative range, because the energy density of different types of coal (J/kg) can vary by a factor of 5; the coal could come from a deep mine or an open-cast; and the amount and kind of mechanisation varies hugely.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But these huge &lt;em&gt;relative&lt;/em&gt; variations are completely swamped in &lt;em&gt;absolute&lt;/em&gt; terms by the other losses, which are at the very best 20%, and can be 65% or so. Which is why there's not a huge amount of literature on the energy inputs to coal extraction: it's such a small part of total losses, that it gets lost in the rounding.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the British residential electricity supply, there's about 7% losses from local distribution (UK figure), 2-3% from transmission grid, and about 60% losses at the plant itself, in the form of heat (NB efficiencies here are multiplicative, rather than additive). The British average for 2013 was 64.2% losses in plant - see &lt;a href=&quot;https://www.gov.uk/government/statistics/electricity-chapter-5-digest-of-united-kingdom-energy-statistics-dukes&quot;&gt;DUKES 2014&lt;/a&gt; table 5.9&lt;/p&gt;&#xA;&#xA;&lt;p&gt;CHP plants mitigate this by capturing a large share of the heat, for distribution in local heat grids. But they still have losses of 5-25% at the plant itself, and then further losses in the heat and electricity distribution system. Call it 20% losses in the best case. Denmark has a lot of high-efficiency coal plants and CHP, but still only managed 55% efficiency, so 45% losses (Danish Electricity Supply '08 Statistical Survey, Table 10).&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="100" LastEditDate="2014-08-24T15:22:53.273" LastActivityDate="2014-08-24T15:22:53.273" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2407" PostTypeId="1" AcceptedAnswerId="2408" CreationDate="2014-08-24T21:19:10.027" Score="7" ViewCount="459" Body="&lt;p&gt;Surely if a plate motion is a straight line across a sphere, this can be described by a fixed Euler pole, however I've been reading about a problem which I confess I don't fully understand which is titled the &quot;Three Plate Problem&quot; and talks about if three plates are moving relative to eachother, one of these relative motions will be described by an Euler pole that wanders. Why is this?&lt;/p&gt;&#xA;" OwnerUserId="389" LastEditorUserId="124" LastEditDate="2014-08-25T06:20:02.517" LastActivityDate="2014-08-25T06:20:02.517" Title="Why do Euler poles for plate motions not stay fixed in time?" Tags="|geophysics|plate-tectonics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2408" PostTypeId="2" ParentId="2407" CreationDate="2014-08-25T04:13:59.180" Score="4" Body="&lt;p&gt;I think I can do an OK job explaining, but I could not find a proper diagram to illustrate this. Perhaps, if you could locate a professor at your university to draw this out and explain it would be best, as doing an illustration on computer is a bit time consuming.&#xA;Lets start out with a two plate system, plate $A$ and $B$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;${}_{A}E_B$ is the relative plate motion of $B$ with respect to $A$, meaning that $A's$ motion is fixed while $B$ is free to rotate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since this is only a two plate mode, $A$ and $B's$ relative plate motions are always the same, no matter where they are in time, you can always go back and forawrd in time, as nothing changes the relationship between  $A$ and $B$. IE, there is nothing to interfere with their relative plate motions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Only 1 Euler pole is needed to fully describe the motions of two plates, in general. Lets now add a 3rd plate, plate C:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;${}_AE_B$ is the plate motion of $B$ with respect to $A$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;${}_BE_C$ is the plate motion of $C$ with respect to $B$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;${}_CE_A$ is the plate motion of $A$ with respect to $C$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These three motions describe the 3 plate system.  So now lets imagine we are standing on $A$ looking at $B$ and $C$, what happens? Since we are on $A$, we move relative to $C$, and $B$ moves relative to us. But wait, a problem occurs, because $C's$ motion is dependent on $B$ being relatively fixed, and $A's$ motion is dependent on $C$ being relatively fixed, meaning if two poles are fixed, the third and final pole &lt;strong&gt;must wander to accommodate the reference frame&lt;/strong&gt;. IE, because All of the plates are moving relative to each other (depending on the reference frame), the Euler poles are changing over time. This gets more complex as we keep on adding plates into the system.  &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-08-25T04:13:59.180" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2410" PostTypeId="1" AcceptedAnswerId="2416" CreationDate="2014-08-27T19:01:27.877" Score="25" ViewCount="5383" Body="&lt;p&gt;We often seem to accept the idea that there were periods of time in which the entire surface of Earth was frozen, for the most part. This implies that there were periods of time in which the entire surface was NOT frozen over. Thus, there must have been heat and energy present on the surface. How did all that energy move to cause an ice age? It seems absurd for all that energy to just radiate into space or move deep into the Earth.&lt;/p&gt;&#xA;" OwnerUserId="813" LastEditorUserId="11908" LastEditorDisplayName="user889" LastEditDate="2019-03-14T00:43:12.033" LastActivityDate="2019-03-14T00:43:12.033" Title="During the &quot;Ice Ages&quot; or &quot;Snowball Earth&quot; times, where was all the energy?" Tags="|plate-tectonics|earth-history|glaciology|ice-age|" AnswerCount="5" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2411" PostTypeId="2" ParentId="2410" CreationDate="2014-08-27T19:54:59.330" Score="15" Body="&lt;p&gt;Of course it isn't &quot;absurd&quot;, and looking at the ball-park energy budget figures you'll see why:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, I don't think anyone is claiming the Earth is completely frozen. More of a &quot;slushy at the Equator&quot; scenario. But let's assume an average 1 km thickness of ice for arguments sake (i.e. probably an exaggeration although polar ice would be thicker).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The current thermal budget &lt;a href=&quot;http://en.wikipedia.org/wiki/Earth%27s_energy_budget%20including%20references.&quot; rel=&quot;nofollow&quot;&gt;can be found here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pertinent figures:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geothermal heat flow (vertically through the rock, primarily from radioactive decay &amp;amp; cooling) is ~$0.084\ \mathrm{W/m^2}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Solar input: $340 \mathrm{W/m^2}$  About a quarter of this is reflected back but this will vary according to conditions (e.g. ice cover, clouds, etc). Assume no reflection. (yes the presence of ice would cause reflection - but it may also reduce cloud cover due to reduced evaporation?).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: geothermal energy is tiny relative to solar flux, so we'll ignore it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That 1 km of ice = 1000m&lt;sup&gt;3&lt;/sup&gt; of ice (per square meter).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's assume that the melting process would also involve an increase in 10C in additional to the latent heat of melting (ie. yes we melt the water but we also increase its temperature a bit).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Total energy required (per $\mathrm{m^3}$) = (Temp increase \times Thermal capacity of water + Latent heat of melting) × volume.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if we plug in our numbers, that would be:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$(10 \times 4.2 + 334) \times 10^6 \times 1000$$&#xA;$$= 3.8 \times 10^{11}\ \mathrm{Joules}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Heat flux for the same area is $340\ \mathrm{J/s}$&#xA;So time for the required energy to melt the ice = $3.8 \times 10^{11} / 340 = 35\ \mathrm{years}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could argue about my ball-park estimates. For example there would be more albedo reflection to melt the ice (=takes longer). And you may not necessarily have to increase the temperature of the water as much ( =&gt;takes less time), and much of the Earth would not have 1 km of ice (=&gt;takes less time). But this gives you a ball park &quot;yes it is feasible&quot;.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Edit: I read the question a bit quickly - the above shows it is 'easy' to get from an ice planet to an ice-free planet. But the converse is also true. The amount of energy that keeps the Earth ice free can easily be added/subtracted over a timescale of a few centuries, just from solar and atmospheric effects.&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorUserId="725" LastEditDate="2014-12-12T07:20:30.223" LastActivityDate="2014-12-12T07:20:30.223" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2412" PostTypeId="1" CreationDate="2014-08-27T20:50:31.470" Score="13" ViewCount="1655" Body="&lt;p&gt;I would be interested in seeing how significant a 5-10 mb drop in pressure would be at the surface, and 80 m in the air. The temporal scale would be 20 minutes. If the pressure starts to steadily increase after the drop in pressure, would this hint that the instruments are measuring data incorrectly, or is there something else at play?&lt;/p&gt;&#xA;" OwnerUserId="814" LastEditorUserId="725" LastEditDate="2014-12-12T07:21:55.587" LastActivityDate="2015-01-12T22:45:14.707" Title="How significant is a 5-10 mb drop in pressure over a 20 minute period?" Tags="|meteorology|barometric-pressure|instrumentation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2415" PostTypeId="1" AcceptedAnswerId="2435" CreationDate="2014-08-28T02:40:38.520" Score="23" ViewCount="17887" Body="&lt;p&gt;What caused the bend in the Emperor/Hawaii chain of islands, 45 million years ago?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has there been any updates to this mystery I am unaware of?  Are there any new theories that could potentially explain it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a lot of material but no answer at the link provided.&#xA;&lt;a href=&quot;http://www.uhh.hawaii.edu/~kenhon/geol205/chain/default.htm&quot; rel=&quot;noreferrer&quot;&gt;University of Hawaii material discussing the root cause of the pattern of formation of the Emperor and Hawaii chain of islands&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;an excerpt...&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Perhaps it is even more amazing that in the past 65 million years&#xA;  there has been only one such bend. Even more remarkable is the&#xA;  observation that the straight portions of the chain are straight. As&#xA;  we shall see below, the configuration of the plate boundaries in the&#xA;  Pacific have changed dramatically during the lifetime of the Hawaiian&#xA;  hotspot. If, as many geophysicists believe, subduction drives&#xA;  tectonics, then how on earth can the straight parts be so straight and&#xA;  move at constant velocities for tens of millions of years? The answer&#xA;  to these questions remains a mystery!&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/D2vPq.jpg&quot; alt=&quot;Bend in the Emperor Hawaii chain of islands&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;ADDED:  Sept 1st.  an excerpt from a link to information in the comment below. thank you MyCarta, good information:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The bend in the Hawaiian-Emperor seamount chain is a prominent&#xA;  feature usually attributed to a change in Pacific plate motion approx&#xA;  47 Myr ago. However, global plate motion reconstructions fail to&#xA;  predict the bend. Here we show how the geometry of the&#xA;  Hawaiian-Emperor chain and other hotspot tracks can be explained when&#xA;  we combine global plate motions with intraplate deformation and&#xA;  movement of hotspot plumes through distortion by global mantle flow.&#xA;  Global mantle flow models predict a southward motion of the Hawaiian&#xA;  hotspot. This, in combination with a plate motion reconstruction&#xA;  connecting Pacific and African plates through Antarctica, predicts the&#xA;  Hawaiian track correctly since the date of the bend, but predicts the&#xA;  chain to be too far west before it. But if a reconstruction through&#xA;  Australia and Lord Howe rise is used instead, the track is predicted&#xA;  correctly back to 65 Myr ago, including the bend. The difference&#xA;  between the two predictions indicates the effect of intraplate&#xA;  deformation not yet recognized or else not recorded on the ocean&#xA;  floor. The remaining misfit before 65 Myr ago can be attributed to&#xA;  additional intraplate deformation of similar magnitude.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I don't know if that is definitive or not?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have come across this image showing the lately determined &quot;pattern of expansion&quot; the earth is undergoing:  perhaps then the quote above is indicating a &quot;perceived balance caused in the expansion as correctly predicting and matching the movement of the plume and plates relative to the pattern?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/znO31.jpg&quot; alt=&quot;Pattern of overall tectonic plate expansion&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;****UPDATE Sept 24th -- Information from MyCarta** &lt;/p&gt;&#xA;&#xA;&lt;p&gt;MyCarta &quot;I think the more recent research leans towards a combination of intraplate deformation and movement of the plume itself, combined with the plate motion, e.g.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And about Euler plates, and Lord Howe's Rise&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.earth.northwestern.edu/people/seth/demos/BRICK/brick.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.earth.northwestern.edu/people/seth/demos/BRICK/brick.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;as added in a comment below, quoted from the paper's abstract:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;if a reconstruction through Australia and Lord Howe rise is used&#xA;  instead, the track is predicted correctly back to 65 Myr ago,&#xA;  including the bend.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;From the first paragraph in the paper:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Hotspots are frequently assumed to be fixed and used as a reference&#xA;  frame for plate motions. However, when the Hawaiian hotspot track is&#xA;  predicted from a global plate motion chain based on relative plate&#xA;  motion data, and it is assumed that the Hawaiian hotspot is fixed&#xA;  relative to African hotspots, it does not fit the observed track: the&#xA;  predicted track is essentially straight, lies south of the Hawaiian&#xA;  seamount chain, and has no feature corresponding to the&#xA;  Hawaiian-Emperor bend. Explanation of this misfit requires one of the&#xA;  following, or a combination of them, to be true: (1) motion of Pacific&#xA;  plate hotspots, in particular more than 1,000 km south-westward motion&#xA;  for the Hawaiian hotspot between ,80 Myr ago and the time of the bend&#xA;  and minor southward motion after this time, (2) motion of hotspots in&#xA;  the African hemisphere, (3) motion at an additional plate boundary, or&#xA;  (4) deformation at a diffuse intraplate boundary not included in the&#xA;  plate motion chain. Palaeomagnetic data from the Emperor chain3 yield&#xA;  a southward component of Hawaiian hotspot motion more than 1,000 km&#xA;  relative to the palaeomagnetic axis between ,80 and 49 Myr ago.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In the rest of the paper they used 2 main models (other models were discarded). The first included only hotspot motion which is sufficient to explain discrepancies between predicted and observed hotspot tracks (e.g. Hawaiian-Emperor chain) back to 47 Ma ago, but before 47 Ma ago the predicted hotspot tracks do not include the bend. Their second model added intraplate deformation (in their reference plates Antarctica/New Zealand) to hotspot motion and is able to predict the hotspot track all the way back to 65 Ma ago with good accuracy, including the bend, and with less accuracy (meaning that it is off too far to the west) until 85 My ago.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Sept 24th MORE QUESTION&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm getting the feeling tectonic plate heave and settle and patterns of interaction are the current best theory for the resulting relative motion of the Hawaii hotspot.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So we are increasing the scale of the question to ask what is it that drives the schedule of the tectonic plates, such that the result is the ever so slow motion of the Hawaii hotspot.  What is felt to be the root cause of &lt;strong&gt;timing&lt;/strong&gt; of plate and continent shift??&lt;/p&gt;&#xA;" OwnerUserId="809" LastEditorUserId="595" LastEditDate="2019-04-10T13:10:48.090" LastActivityDate="2021-04-13T12:09:34.903" Title="What caused the bend in the Emperor/Hawaii chain of islands, 45 million years ago?" Tags="|geology|plate-tectonics|hotspot|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="2416" PostTypeId="2" ParentId="2410" CreationDate="2014-08-28T07:06:13.577" Score="31" Body="&lt;p&gt;I'm not quite sure if the question is asking about glacial, ice ages, or snowball Earth, and whether it's about the onset or end of a glacial period. I'll try to hit all three.&lt;/p&gt;&#xA;&lt;h2&gt;Ice Ages and Milankovitch Cycles&lt;/h2&gt;&#xA;&lt;p&gt;Ice ages are long spans of time that marked by periods of time during which ice reaches far from the poles, interspersed by periods during which the ice retreats (but never quite goes away). The periods of time during which ice covers a good sized fraction of the Earth are called glacials; the periods during which ice retreats to only cover areas in the far north and far south are called interglacials. We are living in ice age conditions, right now. There's still ice on Antarctica and Greenland. We are also in an interglacial period within that larger ice age. The current ice age began about 33 million years ago while the current interglacial began about 11,700 years ago.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;http://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;noreferrer&quot;&gt;Milankovitch cycles&lt;/a&gt; determine whether the Earth is in a glacial or interglacial period. Conditions are right for ice to form and spread when precession puts northern hemisphere summer near aphelion and winter near perihelion and when both obliquity and eccentricity are low. The Earth currently satisfies the first of those conditions, but obliquity and eccentricity are a bit too high. That makes our northern hemisphere summers are a bit too warm, our winters a bit too cold.&lt;/p&gt;&#xA;&lt;p&gt;The Milankovitch cycles] provides several answers to the question &amp;quot;where does the energy go?&amp;quot; Those times when conditions are ripe for glaciation have energy in the northern hemisphere spread more uniformly across the year than times not conducive to glaciation. Summers are milder, which means accumulated snow doesn't melt as much. Winters are milder, which means more snow falls.&lt;/p&gt;&#xA;&lt;p&gt;Once ice does become ubiquitous, another answer to the &amp;quot;where does the energy go&amp;quot; question is into space. Ice and snow are white. Their presence reduces the amount of sunlight absorbed by the Earth.&lt;/p&gt;&#xA;&lt;p&gt;The first paper listed below by Hays et al. is the seminal paper that brought the concept of Milankovitch cycles to the forefront. The second paper by Abe-Ouchi et al. dicusses a recent climate simulation that successfully recovers many salient features of the most recent glaciations. Most importantly, this paper appears to have solved the 100,000 year mystery and shows why deglaciation operates so quickly.&lt;/p&gt;&#xA;&lt;br&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://courses.washington.edu/proxies/Hays-Pacemaker_of_Ice_Ages-Sci76.pdf&quot; rel=&quot;noreferrer&quot;&gt;Hays, J. D., Imbrie, J., &amp;amp; Shackleton, N. J. (1976, December). &amp;quot;Variations in the Earth's orbit: Pacemaker of the ice ages.&amp;quot; &lt;em&gt;American Association for the Advancement of Science.&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/nature/journal/v500/n7461/abs/nature12374.html&quot; rel=&quot;noreferrer&quot;&gt;Abe-Ouchi, A., Saito, F., Kawamura, K., Raymo, M. E., Okuno, J. I., Takahashi, K., &amp;amp; Blatter, H. (2013). &amp;quot;Insolation-driven 100,000-year glacial cycles and hysteresis of ice-sheet volume.&amp;quot; &lt;em&gt;Nature&lt;/em&gt;, 500(7461), 190-193.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;h2&gt;Icehouse Earth vs Greenhouse Earth&lt;/h2&gt;&#xA;&lt;p&gt;The Earth's climate appears to have been toggling between two climate extremes for much of the Earth's existence, one where things are cold and ice is likely to form and the other where ice is absent worldwide except maybe right at the poles. Dinosaurs roamed the arctic and Antarctica when the Earth was in one of its greenhouse phases. The Earth has been in a greenhouse phase for most of the Earth's existence.&lt;/p&gt;&#xA;&lt;p&gt;Milankovitch cycles don't cause glaciation during greenhouse Earth periods. Ice ages happen when the Earth is in an icehouse phase. What appears to distinguish greenhouse and icehouse phases are the positions and orientations of the continents. Having a continent located over a pole helps cool the climate. Having continents oriented so they channel ocean circulation in a way that keeps the ocean cool also helps cool the climate.&lt;/p&gt;&#xA;&lt;p&gt;The Earth transitioned from its hothouse mode to its icehouse mode 33 million years ago or so. That's right about when two key events happened in the ocean. Up until then, Antarctica was still connected to both Australia and South America. The separation from Tasmania formed the Tasmanian Gateway, while the separation from South America formed the Drake Passage. This marked the birth of the very cold Southern Ocean, it marked the buildup of ice on Antarctica, and it marked the end of the Eocene.&lt;/p&gt;&#xA;&lt;br&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.pnas.org/content/110/24/9645.abstract&quot; rel=&quot;noreferrer&quot;&gt;Bijl, P. K., Bendle, J. A., Bohaty, S. M., Pross, J., Schouten, S., Tauxe, L., ... &amp;amp; Yamane, M. (2013). &amp;quot;Eocene cooling linked to early flow across the Tasmanian Gateway.&amp;quot; &lt;em&gt;Proceedings of the National Academy of Sciences&lt;/em&gt;, 110(24), 9645-9650.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://a.ennyu.com/pdf/Exon_JoiJour_00.pdf&quot; rel=&quot;noreferrer&quot;&gt;Exon, N., Kennett, J., &amp;amp; Malone, M. Leg 189 Shipboard Scientific Party (2000). &amp;quot;The opening of the Tasmanian gateway drove global Cenozoic paleoclimatic and paleoceanographic changes: Results of Leg 189.&amp;quot; &lt;em&gt;JOIDES J&lt;/em&gt;, 26(2), 11-18.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;h2&gt;Snowball Earth and the Faint Young Sun Paradox&lt;/h2&gt;&#xA;&lt;p&gt;Snowball Earth episodes were not your average ice age. Ice typically doesn't come near the tropics, even in the worst of ice ages. Snowball Earth means just that; the snow and ice encroached well into the tropics, possibly extending all the way to the equator.&lt;/p&gt;&#xA;&lt;p&gt;The problem with snowball Earth isn't explaining where all the energy went. The real problem is explaining why the ancient Earth wasn't in a permanent snowball Earth condition, starting from shortly after the Earth radiated away the initial heat from the formation of the Earth.&lt;/p&gt;&#xA;&lt;p&gt;The solar constant is not quite constant. While it doesn't change much at all from year to year, or even century to century, it changes a lot over the course of billions of years. Young G class stars produce considerably less energy than do middle aged G class stars, which in turn produce considerably less energy than do older G class stars. When our Sun was young, it produced only 75% or so as much energy than it does now.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/6/6c/Solar_evolution_%28English%29.svg/544px-Solar_evolution_%28English%29.svg.png&quot; alt=&quot;&quot; /&gt;&lt;br /&gt;&#xA;Image source: &lt;a href=&quot;http://en.wikipedia.org/wiki/File:Solar_evolution_(English).svg&quot; rel=&quot;noreferrer&quot;&gt;http://en.wikipedia.org/wiki/File:Solar_evolution_(English).svg&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;By all rights, the Earth should have been completely covered with ice. The young Sun did not produce enough energy to support open oceans. This obviously was not the case. There is plenty of geological evidence that the Earth had open oceans even when the Earth was quite young.&lt;/p&gt;&#xA;&lt;p&gt;This 40 year old conundrum, first raised by Carl Sagan and George Mullen, is the &lt;a href=&quot;http://en.wikipedia.org/wiki/Faint_young_Sun_paradox&quot; rel=&quot;noreferrer&quot;&gt;faint young Sun paradox&lt;/a&gt;. There have been a number of proposed ways out of the paradox, but none of them quite line up with the geological evidence.&lt;/p&gt;&#xA;&lt;p&gt;One obvious way out is that the Earth's early atmosphere was very different from our nitrogen-oxygen atmosphere and contained significantly more greenhouse gases. The amount of greenhouse gases needed to avert a permanent snowball Earth is highly debated, ranging from not much at all to extreme amounts. Another way out is a reduced albedo due to the significantly smaller early continents and lack of life. The young Earth would have been mostly ocean, and ocean water is rather dark (unless it's covered with ice). Lack of life means no biogenic cloud condensation nuclei, which means fewer clouds.&lt;/p&gt;&#xA;&lt;br&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/nature/journal/v474/n7349/abs/nature09961.html&quot; rel=&quot;noreferrer&quot;&gt;Goldblatt, C., &amp;amp; Zahnle, K. J. (2011). &amp;quot;Faint young Sun paradox remains.&amp;quot; &lt;em&gt;Nature&lt;/em&gt;, 474(7349), E1-E1.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2012GL054381/abstract&quot; rel=&quot;noreferrer&quot;&gt;Kienert, H., Feulner, G., &amp;amp; Petoukhov, V. (2012). &amp;quot;Faint young Sun problem more severe due to ice‐albedo feedback and higher rotation rate of the early Earth.&amp;quot; &lt;em&gt;Geophysical Research Letters&lt;/em&gt;, 39(23).&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/nature/journal/v464/n7289/abs/nature08955.html&quot; rel=&quot;noreferrer&quot;&gt;Rosing, M. T., Bird, D. K., Sleep, N. H., &amp;amp; Bjerrum, C. J. (2010). &amp;quot;No climate paradox under the faint early Sun.&amp;quot; &lt;em&gt;Nature&lt;/em&gt;, 464(7289), 744-747.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-08-28T11:45:21.807" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2417" PostTypeId="2" ParentId="2410" CreationDate="2014-08-28T07:39:45.700" Score="0" Body="&lt;p&gt;What's not been touched yet, and the current answers do cover a lot of ground, is the variability of solar input.&lt;br/&gt;&#xA;&lt;br/&gt;&#xA;Even IF the amount of energy radiated out by the earth remains the same (and it probably would, roughly), solar input is highly variable and is a major factor in determining the total energy budget of the planet.&lt;br/&gt;&#xA;Even a small change can have far reaching consequences. Thus if the sun's output goes down by only a few percent (and that's well within its variability even over the 11 year sunspot cycle) temperatures on earth will swing with that (over that short a cycle that's pretty much averaged out by changes in ocean currents). If such a &quot;dip&quot; lasts longer, think a few centuries, you get a &quot;little ice age&quot; as we just emerged from in the 19th century (and by some accounts may be on the verge of slipping into the next, as the sun is again seemingly rather inactive).&lt;br/&gt;&#xA;And the sun has longer cycles, such a low activity cycle lasting a few thousand years can well drop the earth into a full scale ice age. And as the ice sheets grow, reflection goes up, less energy heats the planet, less clouds form. Until the sun enters a high activity phase again, the planet will remain (relatively) cold.&lt;br/&gt;&#xA;As said, this is unlikely to cause the entire planet to disappear under a blanket of ice. The last major ice age &quot;only&quot; came down to about the latitude of the Rhine delta in Europe for example. &lt;/p&gt;&#xA;" OwnerUserId="818" LastActivityDate="2014-08-28T07:39:45.700" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2418" PostTypeId="2" ParentId="2391" CreationDate="2014-08-28T18:10:55.860" Score="5" Body="&lt;p&gt;First I would like to say this is not my area of expertise, so this should perhaps be a comment but I am not allowed yet to comment on this site.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a simplistic view a geyser has heated water chamber with a column of water above it.  The water is heated above the normal boiling temperature but is kept liquid by the pressure of the water column above it.  When the water eventually starts to vaporize this reduces the pressure on the water in the chamber resulting in more rapid vaporization of the water in the chamber resulting in the eruption.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For Old Faithful assume two chambers, one chamber is lower than the other. If the temperatures in both chambers are high enough the vaporization in the upper chamber would also reduce the pressure in the lower chamber allowing it to vaporize resulting in both chambers emptying, resulting in a longer eruption.  Assuming the infill and heating rates are essentially constant then the time before the next eruption would take longer because both chambers are &quot;empty&quot;.  On the other hand if the upper chamber vaporizes and but the lower one does not, either because it is not hot enough or the pressure hasn't dropped enough or back pressure from the upper chamber keeps the lower chamber liquid, then only the upper chamber will empty resulting in less time to infill and reheat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Again not my area.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2014-08-28T18:10:55.860" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2419" PostTypeId="1" CreationDate="2014-08-28T21:36:03.960" Score="15" ViewCount="829" Body="&lt;p&gt;As I understand, the dissolving of carbon dioxide leads to increased acidification of the oceans, and thus increased atmospheric CO&lt;sub&gt;2&lt;/sub&gt; levels would lead to more dissolution in the oceans and thus increased levels of carbonic acid. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, also as CO&lt;sub&gt;2&lt;/sub&gt; is a gas, it's solubility decreases with temperature, thus as atmospheric CO&lt;sub&gt;2&lt;/sub&gt; increase leads to higher surface ocean temperatures via greenhouse effect, does this reduce the solubility of CO&lt;sub&gt;2&lt;/sub&gt; in the oceans to any degree, in some sense limiting the effect of increased gas concentrations on the acidification. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore on a slight tangent, surely the carbonate buffering system of the ocean is large enough to withstand the effects of more dissolved atmospheric carbon dioxide to maintain a constant pH?&lt;/p&gt;&#xA;" OwnerUserId="389" LastEditorUserId="6129" LastEditDate="2020-05-31T18:43:16.917" LastActivityDate="2022-11-25T21:01:28.927" Title="Does the heating of the oceans due to greenhouse effect negate the acidification due to increased CO2 levels?" Tags="|oceanography|geochemistry|carbon-cycle|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2420" PostTypeId="1" CreationDate="2014-08-29T01:20:10.150" Score="7" ViewCount="72" Body="&lt;p&gt;Currently, oceans cover about 71% of the total area of Earth. Ice ages can cause this figure to fluctuate, by lowering the sea level and creating land bridges and other features.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How much can this figure fluctuate by? What were the most recent high and low points?&lt;/p&gt;&#xA;" OwnerUserId="85" LastEditorUserId="11908" LastEditDate="2019-03-17T19:43:00.543" LastActivityDate="2019-03-17T19:43:00.543" Title="How much does ocean cover percentage change between glacial periods?" Tags="|oceanography|earth-history|glaciology|sea-level|ice-age|" AnswerCount="0" CommentCount="0" ClosedDate="2014-12-12T15:03:58.130" ContentLicense="CC BY-SA 3.0" />
  <row Id="2421" PostTypeId="1" AcceptedAnswerId="2422" CreationDate="2014-08-29T01:28:38.123" Score="14" ViewCount="1782" Body="&lt;p&gt;Throughout geologic history, Earth's continents have broken apart and come together to form supercontinents multiple times, in a somewhat regular period, known as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Supercontinent_cycle&quot;&gt;supercontinent cycle&lt;/a&gt;. The length of a cycle is estimated to be 450 million years, with the most recent supercontinent Pangaea forming about 300 mya.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What processes cause this cycle and length? That is, why hasn't continental drift stabilized to some equilibrium (one supercontinent, or separate continents), or why can we observe regular periods? Is the cycle due to change in the future, and why?&lt;/p&gt;&#xA;" OwnerUserId="85" LastEditorDisplayName="user12525" LastEditDate="2019-04-28T11:56:53.657" LastActivityDate="2019-04-28T11:56:53.657" Title="What are the causes of the supercontinent cycle?" Tags="|geology|geophysics|plate-tectonics|geodynamics|paleogeography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2422" PostTypeId="2" ParentId="2421" CreationDate="2014-08-29T07:02:08.030" Score="13" Body="&lt;p&gt;&lt;em&gt;&lt;sub&gt;Please take into consideration that I am not a specialist of plate tectonics, just a paleontologist.&lt;/sub&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although this cycle is often nicknamed the Wilson cycle (probably because of &lt;strong&gt;Wilson, 1966&lt;/strong&gt;), the idea that supercontinent formed cyclically every 440Ma was advanced by &lt;strong&gt;Worsley et al. 1984&lt;/strong&gt; (see review on the subject by &lt;strong&gt;Nance &amp;amp; Murphy 2013&lt;/strong&gt;).&lt;br&gt;&#xA;The mechanism they hypothesize for the breakup of the supercontinent is the mantle heat flow accumulating below the supercontinent while the formation of the supercontinents are bound by the cooling effect on the density of the oceanic lithosphere (see also &lt;strong&gt;Nance et al. 1988&lt;/strong&gt;): so basically, heat accumulate below the insulating supercontinent until it causes it to break up, thus creating rifts and a new oceanic lithosphere, which, with age, cool down and thus become more dense making it more prone to be subducted by the continents (if I understood correctly).&lt;br&gt;&#xA;As to &quot;why ca. 450 Ma?&quot; this has probably to do with the cooling speed of the oceanic lithosphere, I would assume.&lt;br&gt;&#xA;Another important point: although there are evidences for the existence of a supercontinent breaking-up at 300 Ma (Pangaea), at 750 Ma (Rodinia), at 1.6 Ga (Nuna or Columbia), etc., there are also evidences for an absence of supercontinent at 1.2 Ga (see &lt;strong&gt;Pisarevsky et al. 2014&lt;/strong&gt;), hinting that this cycle is maybe not that regular.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;References:&lt;br&gt;&#xA;Nance &amp;amp; Murphy, 2013. &lt;a href=&quot;http://dx.doi.org/10.1016/j.gsf.2012.12.007&quot;&gt;Origins of the Supercontinent Cycle&lt;/a&gt;. Geoscience Frontiers, 4(4): 439-448.&lt;br&gt;&#xA;Nance, Worsley &amp;amp; Moody, 1988. &lt;a href=&quot;http://www.as.wvu.edu/biology/bio463/Nance%20et%20al%201988%20Supercontinent%20Cycle.pdf&quot;&gt;The Supercontinent Cycle.&lt;/a&gt; Scientific American, 259: 72-79.&lt;br&gt;&#xA;Pisarevsky, Wingate, Li, Wang, Tohver &amp;amp; Kirkland, 2014. &lt;a href=&quot;http://dx.doi.org/10.1016/j.precamres.2014.02.011&quot;&gt;Age and paleomagnetism of the 1210 Ma Gnowangerup–Fraser dyke swarm, Western Australia, and implications for late Mesoproterozoic paleogeography&lt;/a&gt;. Precambrian Research, 246: 1-15.&lt;br&gt;&#xA;Wilson, 1966. &lt;a href=&quot;http://dx.doi.org/10.1038/211676a0&quot;&gt;Did the Atlantic close and then re-open?&lt;/a&gt;. Nature, 211: 676-681.&lt;br&gt;&#xA;Worsley, Nance &amp;amp; Moody, 1984. &lt;a href=&quot;http://dx.doi.org/10.1016/0025-3227(84)90209-3&quot;&gt;Global Tectonics and Eustasy for the past 2 billion years&lt;/a&gt;. Marine Geology, 58: 373-400.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-08-29T11:21:07.000" LastActivityDate="2014-08-29T11:21:07.000" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2423" PostTypeId="1" AcceptedAnswerId="2611" CreationDate="2014-08-29T19:29:01.053" Score="15" ViewCount="1204" Body="&lt;p&gt;Defining the Péclet number as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$Pe = \frac{U \lambda}{\kappa}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where $U$ is the characteristic fluid velocity, $\lambda$ is the wavelength of the internal wave and $\kappa$ is the turbulent eddy diffusivity. I found in &lt;a href=&quot;http://dx.doi.org/10.1175/1520-0485(2003)033%3C2093:SAGOTA%3E2.0.CO;2&quot;&gt;Moum et al. (2003)&lt;/a&gt; that measurements show the mean of turbulent eddy diffusivity in Internal Solitary Waves is $\kappa = 0.005$ m$^2$ s$^{-1}$, and a typical velocity is $U = 0.6$ m s$^{-1}$. So for a $1000$ m wave I arrive at a Péclet number:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$Pe = 120,000$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In your experience is that a typical value that you have observed?&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2016-08-19T05:41:14.147" LastActivityDate="2016-08-19T05:41:14.147" Title="What is a typical value of the Péclet number for internal waves?" Tags="|ocean|oceanography|waves|scaling|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2424" PostTypeId="1" CreationDate="2014-08-30T07:12:51.917" Score="12" ViewCount="327" Body="&lt;p&gt;What is the range of horizontal pressure gradients typically caused by the differential heating of land and water under sea breeze conditions?&lt;/p&gt;&#xA;" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2014-10-17T16:00:05.743" LastActivityDate="2014-10-17T16:00:05.743" Title="Sea breeze - magnitude of horizontal pressure gradient?" Tags="|meteorology|wind|scaling|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2425" PostTypeId="1" AcceptedAnswerId="2428" CreationDate="2014-08-30T08:17:35.503" Score="17" ViewCount="786" Body="&lt;p&gt;One of the more widespread &quot;renewable&quot; ways of generating power is by harnessing hydropower, i.e. by exploiting the movement of falling or flowing water. Some of the most commonly seen implementations are river dams and tidal power stations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;All hydroelectric power stations obviously remove some kinetic energy from the water, usually by requiring it to turn a turbine. What I'm curious about is whether the removal of this energy is actually sustainable, i.e. whether energy is introduced back into these bodies of water at such a rate that we don't need to worry about depleting our bodies of water of kinetic energy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some might say that removing kinetic energy from the oceans on that scale is an obvious impossibility, but this strikes me as a foolish assumption in light of the &lt;em&gt;dilution hypothesis&lt;/em&gt;, which clearly turned out false. Two-hundred years ago, people assumed that the oceans were so incredibly vast that man could never have an environmental impact on them. Today, here we stand, with oceanic acidification, warming, and overfishing being prime environmental concerns. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The exact same question and argument can be repeated for wind energy. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do we have any idea exactly what the patterns and rates of energy transfer into our planet's water (and wind) systems are? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What are the potential environmental impacts of the large-scale removal of kinetic energy from our bodies of water?&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Note: among these environmental impacts, please don't focus on well-known impacts like damage to local ecosystems, loss of land, noise pollution, etc. I am chiefly interested in how this way of generating power affects our natural systems of energy storage and circulation, like oceanic and wind currents.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following question is off-topic, but it's a good follow-up: how is energy even introduced into our oceanic and wind current-systems? For example, I assume the moon's push-pull is responsible for the tidal movement of the oceans. What impact does the sun play? How fast is this entire system of energy transfer?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Comment: I strongly endorse the use of wind and hydropower as sources of energy over the further use of fossil fuels. However, I still think it is important to do research into the actual renewability of presumed-renewable energy sources, as we don't want to end up with another fossil fuel-type situation, in which we become aware of dependency on these energy sources and their malignant environmental side-effects long after widespread enthusiastic adoption. &lt;/p&gt;&#xA;" OwnerUserId="666" LastEditorUserId="192" LastEditDate="2014-09-01T17:51:18.733" LastActivityDate="2014-12-12T07:40:32.670" Title="To what extent is hydroelectric power really renewable?" Tags="|atmosphere|ocean|hydrology|climate-change|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2427" PostTypeId="1" CreationDate="2014-08-30T21:42:16.937" Score="10" ViewCount="808" Body="&lt;p&gt;When looking at &lt;a href=&quot;https://en.wikipedia.org/wiki/Temperature_record#The_long_term_ice_core_record:_the_last_800.2C000_years&quot;&gt;the long term ice-core temperature record&lt;/a&gt;, it very clearly shows a ~100,000 year cyclical trend with warming spikes and gradual cooling. To the untrained eye, it seems that such a trend has not been significantly deviated from so far (in the present day). This would indicate to me that the current upward temperature trend is not human-caused. What refutes that idea?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also a relevant question: what is the confidence of this temperature record and what are the probable deviations from the temperatures indicated in that graph?&lt;/p&gt;&#xA;" OwnerUserId="838" LastActivityDate="2014-11-19T05:12:36.280" Title="Does the long-term ice-core temperature record provide reasonable evidence that the current temperature trend is not anthropogenic?" Tags="|temperature|climate-change|" AnswerCount="2" CommentCount="13" ContentLicense="CC BY-SA 3.0" />
  <row Id="2428" PostTypeId="2" ParentId="2425" CreationDate="2014-08-31T08:31:53.323" Score="21" Body="&lt;p&gt;Electricity from waves, from hydro (both run-of-river and storage) and from wind, are all indirect forms of solar power. Electricity from tides is different, and we can deal with that in a separate question. Global tidal electricity generation is not yet at the scale of gigawatts, so it's tiny for now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Winds come about from the sun heating different parts of the planet at different rates, due to insolation angles, varying cloud cover, varying surface reflectivity, and varying specific heat of surface materials. Temperature differentials create wind currents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Waves come about from wind, so they're a twice-indirect form of solar power.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sunlight on water speeds up evaporation, lifting the water vapour into clouds, giving them lots of gravitational potential. That rain then falls, sometimes onto high land, from where it can be gathered into storage reservoirs that are tapped for electricity, or where it flows into rivers that are then harnessed in run-of-river hydro.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How much power is there? Well, the insolation from the sun is, at the outer boundary of the Earth's atmosphere, at an intensity of &lt;a href=&quot;http://www.acrim.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;about 1400 Watts per square metre&lt;/a&gt;. The Earth's albedo is roughly about 30% - i.e. on average about 400 Watts are reflected back into space, giving an average irradiation into the Earth of about 1000 Watts per square metre. Picture the Earth's surface as seen from the Sun: wherever the Earth is in its orbit on its own axis, and around the Sun, the Sun sees a disc that has the Earth's diameter, so the surface area exposed to the Sun is just $\pi$ times the square of Earth's radius, which is about 6 300 kilometres.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the incoming solar radiation is $1000 \times 6,300,000^2 \times \pi \approx 125 \times 10^{15} \rm \ W$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Current human consumption of non-food energy is about &lt;a href=&quot;http://www.wolframalpha.com/input/?i=world%20primary%20energy%20supply%20in%20terawatts&quot; rel=&quot;nofollow noreferrer&quot;&gt;17 TW&lt;/a&gt;, i.e. $17 \times 10^{12} \rm \ W$, which is about four orders of magnitude smaller than insolation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is an interesting open academic discussion (&lt;a href=&quot;https://skeptics.stackexchange.com/a/15178/6236&quot;&gt;see &quot;modelling methodology smackdown&quot; section&lt;/a&gt;) about how much energy we can physically extract from wind: some models say it's only a few times as much as all the energy we currently use; others say it's another order of magnitude more again. Either way, it's way more than we need, so while it's an interesting modelling discussion, the answer wouldn't change anything right now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are also open academic discussions about the impact of removing terawatts of wind energy, on regional climates. However, regional climates are already one of the more uncertain parts of long-term climate forecasts; add to that the high uncertainties around where the energy extraction would be, and what the specific effects of extraction are, and we end up with a lot of speculation and very little usable information. Not that this has prevented people from trying to model it, and reporting their results: but the uncertainties dwarf the results.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And harnessing renewables doesn't change anything significant in the Earth's total heat budget either, because almost all of that $1000\ \mathrm{W/m^2}$ from the sun already ends up as low-grade heat anyway. If harnessed for electricity, that electricity will then get used, and almost all of it will then end up as low-grade heat. The bit that will change when we get close to 100% renewables is that we will no longer be injecting about 15 TW of energy from fossil and nuclear into the biosphere (&lt;a href=&quot;http://www.iea.org/publications/freepublications/publication/KeyWorld2013.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;2 TW is renewables&lt;/a&gt;). But that's only about 0.01% of the insolation anyway.&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="-1" LastEditDate="2017-04-13T12:46:45.430" LastActivityDate="2014-12-12T07:40:32.670" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2430" PostTypeId="1" AcceptedAnswerId="2431" CreationDate="2014-08-31T14:28:02.717" Score="15" ViewCount="2170" Body="&lt;p&gt;In most cases (as shown in the figure below), a seismogram shows data from three components:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;North-South&lt;/li&gt;&#xA;&lt;li&gt;East-West&lt;/li&gt;&#xA;&lt;li&gt;Vertical/depth(z)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/kMJ1x.png&quot; alt=&quot;Enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, if these components are not marked and all we have are three figures, then is there a way to identity which figure corresponds to which component?&lt;/p&gt;&#xA;" OwnerUserId="594" LastEditorUserId="502" LastEditDate="2014-08-31T21:48:01.640" LastActivityDate="2014-08-31T21:48:01.640" Title="Interpretation of a seismogram (three components)" Tags="|geophysics|seismology|earthquakes|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2431" PostTypeId="2" ParentId="2430" CreationDate="2014-08-31T15:17:52.903" Score="12" Body="&lt;p&gt;Yes, the vertical component of the seismogram looks different than the horizontal components. There are surface seismic waves (&lt;a href=&quot;http://en.wikipedia.org/wiki/Love_wave&quot;&gt;Love waves&lt;/a&gt; or Q-waves) that are horizontally-polarized. The ground motion due to these waves is horizontal and parallel to the plane of the ground surface. Therefore these waves will be most visible in the horizontal components of the seismogram. In some cases it may be possible to use the horizontal components to estimate the bearing to the epicenter.  Surface waves travel more slowly than body waves, and their amplitude decays at a lower rate, therefore they may be easier to recognize in seismograms measured farther from the epicenter.       &lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-08-31T15:17:52.903" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2432" PostTypeId="1" AcceptedAnswerId="2436" CreationDate="2014-08-31T18:06:29.100" Score="8" ViewCount="105" Body="&lt;p&gt;In a previous question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2400/what-happens-to-the-higher-frequency-content-of-the-tremors-associated-with-a-vo&quot;&gt;What happens to the higher frequency content of the tremors associated with a volcanic eruption?&lt;/a&gt;, I asked about the high(er) frequency content of a volcanic eruption.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the same vein, I'm interested to know more about the influence of the geometry of the magma column on this particular frequency content and the methodologies that researchers use to take measurements of circular vents.  Assuming a uniform cylinder all the way to the magma chamber would aid in the mechanical modeling, but I'm sure this betrays quite a bit of the changes in diameter that take place along the way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are precise measurements of the vents/magma conduits of volcanoes currently possible, or is this too big of a risk to personnel and equipment?  Which particular techniques (e.g., radar/sonar) would work without having to actually enter the chamber?&lt;/p&gt;&#xA;" OwnerUserId="19" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-09-01T02:50:18.090" Title="Are there measurement techniques that can help determine the exact geometry of a volcanic vent?" Tags="|geophysics|measurements|volcanology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2433" PostTypeId="1" AcceptedAnswerId="2444" CreationDate="2014-08-31T19:50:11.970" Score="16" ViewCount="337" Body="&lt;p&gt;I saw this rock formation near &lt;a href=&quot;https://www.google.ch/maps/place/Hveravellir/@64.5253208,-18.9692902,7z/data=!4m2!3m1!1s0x48d3ebf93b256813:0x341fbb98dbd52317&quot; rel=&quot;noreferrer&quot;&gt;Hveravellir&lt;/a&gt;, Iceland. It is probably of volcanic origin and looks like a dome. It is nearly symmetric and appears to consist of hardened lava maybe, with several very big cracks that divide it into sections. It is quite far away from the lava flows of the old, very flat Strytur volcano that is about 2 km away.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have several hypotheses of my own, but I am not a geologist. Could it be a small &quot;failed volcano&quot;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/NY2zb.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="841" LastEditorUserId="18081" LastEditDate="2021-11-08T15:33:23.480" LastActivityDate="2021-11-08T15:33:23.480" Title="How did this rock dome (pictured) form?" Tags="|volcanology|geomorphology|" AnswerCount="2" CommentCount="3" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2434" PostTypeId="1" AcceptedAnswerId="2673" CreationDate="2014-08-31T20:01:12.320" Score="9" ViewCount="433" Body="&lt;p&gt;They consists of stone, of course, but have strange U cross section, as if they were the remaining of some ships without the head and tail section. Could anyone tell how have they formed? They almost perfectly in the center of the old, flat volcano (Strytur) near &lt;a href=&quot;https://www.google.ch/maps/place/Hveravellir/@64.5253208,-18.9692902,7z/data=!4m2!3m1!1s0x48d3ebf93b256813:0x341fbb98dbd52317&quot; rel=&quot;noreferrer&quot;&gt;Hveravellir&lt;/a&gt;, Iceland. They are quite high uphill and I am surprised how lava could get into that place and then made into such a shape as it probably only flows down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/v0JlX.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/svbo5.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="841" LastEditorUserId="841" LastEditDate="2014-09-08T08:46:03.863" LastActivityDate="2014-10-22T13:13:56.340" Title="What are these &quot;ship wrecks&quot; (pictured) in the old volcano crater?" Tags="|volcanology|evolution|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2435" PostTypeId="2" ParentId="2415" CreationDate="2014-09-01T02:08:57.893" Score="15" Body="&lt;p&gt;I don't recall this being considered a real 'mystery'. For decades after Tuzo Wilson's revolutionary Plate Tectonics the accepted explanation was of a change in direction in the plate motion over the mantle plume. I am pretty sure this was still the case when I read Plate Tectonics: How It Works&#xA;(by Cox and Hart, Wilson's former students - I encourage you to get the book and work through it, you get to do plate tectonic reconstruction yourself, with paper and pencil, and calculator) in the late nineties. I think the more recent research leans towards a combination of intraplate deformation and movement of the plume itself, combined with the plate motion, &#xA;e.g.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Prediction of Emperor-Hawaii seamount locations from a revised model of global plate motion and mantle flow by Steinberger et al. (Nature 430, 167-173, 8 July 2004) &#xA;&lt;a href=&quot;http://www.nature.com/nature/journal/v430/n6996/abs/nature02660.html&quot;&gt;http://www.nature.com/nature/journal/v430/n6996/abs/nature02660.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATED&lt;/strong&gt;: as added in a comment below, quoted from the paper's abstract:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;if a reconstruction through Australia and Lord Howe rise is used&#xA;  instead, the track is predicted correctly back to 65 Myr ago,&#xA;  including the bend.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;From the first paragraph in the paper:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Hotspots are frequently assumed to be fixed and used as a reference&#xA;  frame for plate motions. However, when the Hawaiian hotspot track is&#xA;  predicted from a global plate motion chain based on relative plate&#xA;  motion data, and it is assumed that the Hawaiian hotspot is fixed&#xA;  relative to African hotspots, it does not fit the observed track: the&#xA;  predicted track is essentially straight, lies south of the Hawaiian&#xA;  seamount chain, and has no feature corresponding to the&#xA;  Hawaiian-Emperor bend. Explanation of this misfit requires one of the&#xA;  following, or a combination of them, to be true: (1) motion of Pacific&#xA;  plate hotspots, in particular more than 1,000 km south-westward motion&#xA;  for the Hawaiian hotspot between ,80 Myr ago and the time of the bend&#xA;  and minor southward motion after this time, (2) motion of hotspots in&#xA;  the African hemisphere, (3) motion at an additional plate boundary, or&#xA;  (4) deformation at a diffuse intraplate   boundary not included in the&#xA;  plate motion chain. Palaeomagnetic data from the Emperor chain3 yield&#xA;  a southward component of Hawaiian hotspot motion more than 1,000 km&#xA;  relative to the palaeomagnetic axis between ,80 and 49 Myr ago.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In the rest of the paper they used 2 main models (other models were discarded). The first included only hotspot motion which is sufficient to explain discrepancies between predicted and observed hotspot tracks (e.g. Hawaiian-Emperor chain) back to 47 Ma ago, but before 47 Ma ago the predicted hotspot tracks do not include the bend.&#xA;Their second model added intraplate deformation (in their reference plates Antarctica/New Zealand) to hotspot motion and is able to predict the hotspot track all the way back to 65 Ma ago with good accuracy, including the bend, and with less accuracy (meaning that it is off too far to the west) until 85 My ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATED SEPTEMBER 17 2014&lt;/strong&gt;&#xA;The 2004 Nature paper still holds to fixed photspots. It invokes plate circuits (the models I referred to) and intraplate deformation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Following my comments on September 16th, a google search for &quot;bent Hawaiian-Emperor hotspot&quot; returned a 2009 Science article which instead invokes hotspot motion:&#xA;The Bent Hawaiian-Emperor Hotspot Track: Inheriting the Mantle Wind by John Tarduno et al. Science 3 April 2009 (Vol. 324 no. 5923 pp. 50-53). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Abstract at:&#xA;&lt;a href=&quot;http://www.sciencemag.org/content/324/5923/50&quot;&gt;http://www.sciencemag.org/content/324/5923/50&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's a copy of the pdf article at: &lt;a href=&quot;http://www.mantleplumes.org/WebDocuments/Tarduno2009.pdf&quot;&gt;http://www.mantleplumes.org/WebDocuments/Tarduno2009.pdf&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;and a good online animation at:&#xA;&lt;a href=&quot;http://www.earthmodels.org/publications/science-2009&quot;&gt;http://www.earthmodels.org/publications/science-2009&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="144" LastEditorUserId="725" LastEditDate="2014-12-12T07:28:39.977" LastActivityDate="2014-12-12T07:28:39.977" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="2436" PostTypeId="2" ParentId="2432" CreationDate="2014-09-01T02:09:58.757" Score="7" Body="&lt;p&gt;Interferometric synthetic aperture radar (or &lt;a href=&quot;http://en.wikipedia.org/wiki/Interferometric_synthetic_aperture_radar&quot;&gt;InSAR)&lt;/a&gt; is a remote sensing (airplane or, more commonly, satellite) radar techinque used to measure surface deformation. Repeated measurements of radar amplitudes over a common area are used to estimate changes to surface topography. &lt;a href=&quot;http://gji.oxfordjournals.org/content/179/1/549.full.pdf&quot;&gt;InSAR measurements of surface changes have been used with numerical models of dyke propagation to model magma chambers in the East African Rift System&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other geophysical methods that can be used to image/model active magma chambers include seismic interferometry, magnetic and gravity methods. &lt;a href=&quot;http://www.eri.u-tokyo.ac.jp/yaoki/2012EPSL.pdf&quot;&gt;Here&lt;/a&gt; is a recently published example from Japan which used seismic interferometry to image an active magma chamber. Magnetic and gravity measurements can be taken from airplanes, which may be a bit safer than being on the ground. If  the magma chamber has magnetic/density properties different from the surrounding country rock, then mag/grav forward/inverse modelling could be used to create a model of the magma chamber geometry. &lt;/p&gt;&#xA;" OwnerUserId="777" LastEditorUserId="777" LastEditDate="2014-09-01T02:50:18.090" LastActivityDate="2014-09-01T02:50:18.090" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2437" PostTypeId="1" AcceptedAnswerId="2438" CreationDate="2014-09-01T16:33:20.290" Score="8" ViewCount="257" Body="&lt;p&gt;I am looking for a paleogeographic atlas software, like the one used &lt;a href=&quot;http://www.youtube.com/watch?v=cyPUcyODjYI&quot; rel=&quot;nofollow noreferrer&quot;&gt;here at min 10:15&lt;/a&gt;: you can navigate through the ages with an arrow and visualize a reconstruction of the geographic features of any area of the world in a certain age:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Aj8N9.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has anyone got any suggestion? I use Linux (Debian) but I'm interested in software for any operating system.&lt;/p&gt;&#xA;" OwnerUserId="620" LastEditorUserId="595" LastEditDate="2016-07-25T11:37:33.620" LastActivityDate="2016-07-25T12:27:12.530" Title="Paleogeographic atlas software" Tags="|paleogeography|software|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2438" PostTypeId="2" ParentId="2437" CreationDate="2014-09-02T02:30:38.123" Score="12" Body="&lt;p&gt;I haven't seen the video you linked to, but from personal experience &lt;a href=&quot;http://www.gplates.org/&quot;&gt;GPlates&lt;/a&gt; is pretty good.  It's open-source and runs on Windows, Linux and MacOS X. &lt;/p&gt;&#xA;" OwnerUserId="777" LastActivityDate="2014-09-02T02:30:38.123" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2439" PostTypeId="1" CreationDate="2014-09-02T09:32:35.093" Score="26" ViewCount="769" Body="&lt;p&gt;I'm curious about how much is known about this topic: how much has the total amount of life on Earth changed over the 4 billion years or so that it has existed on this planet? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there estimates of global Gross Primary Productivity (GPP), or biomass, or both, for previous geological epochs? If so, how certain are these estimates, and what assumptions are they based on? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the total figures are thought to have changed much in the past, what are the main factors thought to cause these changes? Conversely, if the totals are thought to have been relatively stable, what are the main feedbacks that are thought to have ensured this?&lt;/p&gt;&#xA;" OwnerUserId="215" LastEditorUserId="87" LastEditDate="2014-11-01T10:55:39.617" LastActivityDate="2017-09-19T08:07:51.250" Title="How much have global GPP and biomass changed over Earth's history?" Tags="|earth-history|paleontology|biomass|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2440" PostTypeId="1" AcceptedAnswerId="2443" CreationDate="2014-09-02T11:05:39.997" Score="11" ViewCount="421" Body="&lt;p&gt;In climate modelling, there are three major model types that form the basis of a fully coupled Atmosphere-Ocean General Circulation Model (AOGCM):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Atmosphere circulation models&lt;/li&gt;&#xA;&lt;li&gt;Ocean circulation models&lt;/li&gt;&#xA;&lt;li&gt;Land surface models&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;There are at least 10-15 well-known models of each type that are widely used. Each atmosphere model usually has one, maybe two ocean models, and one or two land surface models that it has been made to work together with as an AOGCM. But if you want to use one atmosphere model with arbitrary ocean and land models, you usually have to modify the models to some degree to get them to play well together.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any projects that aim to be a generic &quot;glue&quot; between any combination of climate models? This could be in the form of a software framework, or it could just be a specification for data format and exchange methods.&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="595" LastEditDate="2016-07-25T11:35:43.540" LastActivityDate="2016-07-25T11:35:43.540" Title="Are there any general-purpose climate-model coupling projects?" Tags="|climate-models|numerical-modelling|ocean-models|land-surface-models|software|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2441" PostTypeId="2" ParentId="2440" CreationDate="2014-09-02T12:27:46.087" Score="10" Body="&lt;p&gt;Coupler software (e.g. &lt;a href=&quot;https://verc.enes.org/oasis&quot;&gt;OASIS&lt;/a&gt;, &lt;a href=&quot;http://www.mcs.anl.gov/research/projects/mct/&quot;&gt;MCT&lt;/a&gt;, &lt;a href=&quot;http://www.geosci-model-dev-discuss.net/7/3889/2014/gmdd-7-3889-2014.html&quot;&gt;C-Coupler&lt;/a&gt;) is frequently used to combine these different components of earth system models. Of course interfacing models with each other using these couplers or other methods always needs some technical work and sometimes also some algorithmic work. Therefore the number of model combinations will always be limited.&lt;/p&gt;&#xA;" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2014-09-02T13:19:28.153" LastActivityDate="2014-09-02T13:19:28.153" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2442" PostTypeId="1" CreationDate="2014-09-02T13:29:41.270" Score="22" ViewCount="994" Body="&lt;p&gt;Climate models outputs, particularly the reanalysis datasets, output wind speeds as zonal and meridional averages for the modelled time period (typically 1, 3 or 6 hours). So we get a 2-dimensional vector, the U and V values, each of which is signed. Together, they give us a mean wind speed, and a mean direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are some oddities there, as I understand it. If the wind within one interval were 9 m/s due East for half the time, then 9 m/s due West for the other half, then the UV values would be (0, 0). That's a very contrived case, just to illustrate the netting off for any wind that switches sign on either the U or V directions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some reanalysis datasets fix this part of the problem by giving mean wind speeds as well as mean UV components. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But for the estimation of wind electricity generation , what we really need are the mean power densities ($\mathrm{W/m^2}$ in the vertical plane) of wind, at turbine hub height (typically 80m or so). That way, we can multiply the swept area of the blades, by the mean power densities, and combine with a modified version of the turbine power curve, to estimate electricity generation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, the relationship between wind speeds and power densities is cubic. But the average of a cubed value is not the same as the cube of the averaged value. So, taking the cube of average wind speeds is not the same as taking the average of the cube of wind speeds. And then there's the possibility of positive or negative correlations between wind speeds and atmospheric pressure, which would also mess with the averaging.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there an analysis of the impact of these distortions on our ability to model &amp;amp; predict wind power generation?&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="100" LastEditDate="2014-12-14T09:18:04.083" LastActivityDate="2016-02-09T23:20:15.877" Title="Significant difference between averaged wind speeds and averaged wind power density, for wind generation modelling?" Tags="|atmosphere|models|wind|climate-models|atmosphere-modelling|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2443" PostTypeId="2" ParentId="2440" CreationDate="2014-09-02T15:34:41.520" Score="10" Body="&lt;p&gt;Yes, there were many model coupling projects in the past, as well as many ongoing coupling projects in the present and near future.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main motivation behind model coupling is the need for the interactive feedback processes between two or more separate physical systems, for example, atmosphere and ocean. Historically, these models have been developed independently of each other, i.e. they were uncoupled - unaware of each other. Given past and current technology and knowledge, modifying the models' source code so that they can exchange information in a consistent manner was a much smaller effort (typically few years) than it would take to develop a unified system model from scratch (i.e. atmosphere-ocean as a single dynamical core). Another advantage to the coupling approach is that different physical systems often describe processes that operate on very different spatial and time scales. Thus, it is often computationally advantageous to let physical systems have distinct models that are &quot;coupled&quot; through an intermediate layer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The vast number of coupling projects throughout the 1990s and 2000s have demonstrated the need for more standardized coupling libraries or frameworks that would cut down on duplication of effort, software bugs and development time. @BHF's answer mentions a few of those. Probably the most mature and feature-rich framework at this point is the &lt;a href=&quot;http://earthsystemmodeling.org&quot;&gt;Earth System Modeling Framework (ESMF)&lt;/a&gt;. ESMF provides data abstraction for geophysical models, field regridding, parallel computation capabilities and many others. ESMF provides Fortran, C and Python (limited) APIs. Many atmosphere, wave, ocean, land and sea-ice models are now ESMF-compliant, so coupling of these models is more feasible than ever. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Indeed, there are also efforts toward a standard and software design convention that would facilitate model development and coupling. Such standard is the &lt;a href=&quot;https://earthsystemcog.org/projects/nuopc/&quot;&gt;NUOPC&lt;/a&gt; layer and is supported by the ESMF library. NUOPC sets the guidelines for software design and field naming conventions that promotes model interoperability. Any models following the NUOPC design conventions will be interoperable with each other out of the box, so the burdain is now moved to the actual model developers to make sure that their packages follow the new standards.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(My PhD thesis in progress uses ESMF to develop a coupled atmosphere-wave-ocean-model.)&lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2014-09-02T15:42:54.247" LastActivityDate="2014-09-02T15:42:54.247" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2444" PostTypeId="2" ParentId="2433" CreationDate="2014-09-03T07:57:54.107" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The vast majority of magma never even makes it out to the surface - most is simply crystallised at depth in magma chambers which dead-end several kilometres below the surface, or are injected as dykes or sills within the host strata.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;By &lt;a href=&quot;http://www.reddit.com/user/OrbitalPete&quot; rel=&quot;nofollow&quot;&gt;OrbitalPete&lt;/a&gt;, &lt;a href=&quot;http://www.reddit.com/r/askscience/comments/2f9qyi/if_island_chains_like_hawaii_were_formed_by_the/&quot; rel=&quot;nofollow&quot;&gt;posted on reddit.com&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If magma rose up below that mound it probably got closer than several kilometres to the surface; and the theory could be tested with one drill hole. I'm assuming the mound itself is not lava as such but bedrock that's been forced up. &lt;/p&gt;&#xA;" OwnerDisplayName="user231" LastEditorUserId="611" LastEditDate="2014-09-16T05:23:00.173" LastActivityDate="2014-09-16T05:23:00.173" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2445" PostTypeId="2" ParentId="2202" CreationDate="2014-09-04T03:45:25.443" Score="4" Body="&lt;p&gt;The Tetens coefficents are the empirically derived coefficients of an equation for calculating the saturation vapour pressure of water. From &lt;a href=&quot;https://en.wikipedia.org/wiki/Clausius%E2%80%93Clapeyron_relation#Meteorology_and_climatology&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;a very good approximation can usually be made using the August-Roche-Magnus formula (usually called the Magnus or Magnus-Tetens approximation, though this attribution is historically inaccurate):&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$e_s(T)= 6.1094 \exp \left( \frac{17.625T}{T+243.04} \right)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;e_s(T) is the equilibrium or saturation vapor pressure in hPa as a function of temperature T on the Celsius scale. Since there is only a weak dependence on temperature of the denominator of the exponent, this equation shows that saturation water vapor pressure changes approximately exponentially with T.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="56" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-09-04T03:45:25.443" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2446" PostTypeId="1" AcceptedAnswerId="2447" CreationDate="2014-09-04T18:55:49.813" Score="12" ViewCount="81" Body="&lt;p&gt;I was reading a bit about the fluid mechanics of volcanoes to further understand some of the dynamics of &amp;quot;magma wagging&amp;quot; from my earlier question.&lt;/p&gt;&#xA;&lt;p&gt;From [2]:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Heterogeneous nucleation, in which the presence of certain crystals (e.g., Fe-Ti oxides) provides nucleation substrates because they lower surface tension, can greatly&#xA;reduce &lt;span class=&quot;math-container&quot;&gt;$\Delta p_{s_{crit}}$&lt;/span&gt; to less than a few megaPascals (Gardner &amp;amp; Denis 2004, Hurwitz &amp;amp; Navon 1994).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I became curious as to what was so special about the Fe-Ti oxides that makes them good nucleation sites, so I looked up [1].  I stumbled upon a different problem, though.  In their procedure, they claimed:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Fe-Ti oxides are either blocky or needle-shaped. Blocky ones&#xA;are 0.5–5&lt;span class=&quot;math-container&quot;&gt;$\mu$&lt;/span&gt;m in size and those large enough were identified&#xA;with an electron microprobe as titano-magnetite, here after&#xA;referred to as magnetite.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Do mixed Fe-Ti oxides essentially have the same physical properties as magnetite?  If the physical properties are in fact even slightly different, why would they be lumped together for analysis in these nucleation studies?&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Gardner, J.E. and Denis, M-H. (2004) Heterogeneous bubble nucleation on Fe-Ti oxide crystals in high-silica rhyolitic melts. &lt;em&gt;Geochimica et Cosmochimica Acta, 68&lt;/em&gt;:7, 3587–3597. &lt;a href=&quot;http://dx.doi.org/10.1016/j.gca.2004.02.021&quot; rel=&quot;noreferrer&quot;&gt;[DOI]&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Gonnermann, H.M. and Manga, M. (2007). The fluid mechanics inside a volcano. &lt;em&gt;Annu. Rev. Fluid Mech, 39&lt;/em&gt;, 321–56. &lt;a href=&quot;http://www.soest.hawaii.edu/GG/SYI/helge/pubs/gonnermann_manga_2007.pdf&quot; rel=&quot;noreferrer&quot;&gt;[PDF]&lt;/a&gt; &lt;a href=&quot;http://dx.doi.org/10.1146/annurev.fluid.39.050905.110207&quot; rel=&quot;noreferrer&quot;&gt;[DOI]&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="19" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-09-05T02:19:49.230" Title="Why are titanium oxides lumped in with magnetite for the purposes of analyzing water bubble nucleation?" Tags="|volcanology|geochemistry|mineralogy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2447" PostTypeId="2" ParentId="2446" CreationDate="2014-09-05T02:19:49.230" Score="8" Body="&lt;p&gt;In &lt;a href=&quot;http://magician.ucsd.edu/essentials/webbookse30.html&quot;&gt;iron oxides&lt;/a&gt;, titanium commonly substitutes for iron in the crystal structure. Two solid solution series are important: the ulvöspinel-magnetite and ilmenite-hematite series.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The composition of a solution changes continuously, without any change in crystal habit. Your reference indicates its the size of crystals than matter for being efficient nucleation sites. Composition is not expected to be important.&lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-09-05T02:19:49.230" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2449" PostTypeId="1" AcceptedAnswerId="2461" CreationDate="2014-09-05T08:23:14.847" Score="10" ViewCount="1712" Body="&lt;p&gt;$q$ is the symbol used for specific humidity in many textbooks and papers (at least in meteorology and climatology, I'm not familiar with it in other disciplines). Where does this symbol come from, and what does it stand for?&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="725" LastEditDate="2014-12-13T10:58:43.657" LastActivityDate="2014-12-13T10:58:43.657" Title="Why is q used for specific humidity?" Tags="|meteorology|terminology|climatology|humidity|" AnswerCount="2" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2450" PostTypeId="2" ParentId="2449" CreationDate="2014-09-06T07:09:36.397" Score="11" Body="&lt;p&gt;The specific humidity &lt;strong&gt;q&lt;/strong&gt; is a &lt;strong&gt;quotient&lt;/strong&gt; - mass of water vapor in mass of moist air. The mass is expressed per volume, i.e. the density of water vapor $\rho_v$ and the density of dry air $\rho_d$ are used for the definition of the quotient $q$ known as specific humidity:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ q = \dfrac{\rho_v}{\rho_v+\rho_d} $$&lt;/p&gt;&#xA;" OwnerUserId="124" LastActivityDate="2014-09-06T07:09:36.397" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2451" PostTypeId="1" AcceptedAnswerId="3046" CreationDate="2014-09-06T23:22:39.113" Score="11" ViewCount="1668" Body="&lt;p&gt;So I was essentially wondering why it was that the basalts on top of 'plumes' at 'hotspots' (sometimes called OIBs, ocean island basalts) and at continental rifting centres are enriched in alkaline metals (Na and K) compared to the tholeiitic MORBs. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, I was wondering if someone could explain to me chemically why it is that alkali basalts are more 'mature' than tholeiites? I.e. Is it that the ions are more incompatible than the calcium ions found in the tholeiites? Why is this? &lt;/p&gt;&#xA;" OwnerUserId="389" LastEditorUserId="725" LastEditDate="2014-12-14T18:11:17.333" LastActivityDate="2014-12-14T18:11:17.333" Title="Why are alkali basalts found at rifting centres and on top of 'plumes', whereas MORBs are generally tholeiitic?" Tags="|geology|volcanology|geochemistry|petrology|magmatism|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2452" PostTypeId="1" CreationDate="2014-09-07T10:38:53.533" Score="10" ViewCount="156" Body="&lt;p&gt;I gather that higher-than-ambient CO&lt;sub&gt;2&lt;/sub&gt; &quot;domes&quot; can form &lt;em&gt;above&lt;/em&gt; urban areas, &lt;a href=&quot;http://dx.doi.org/10.1021/es903018m&quot;&gt;enhancing other local air pollution&lt;/a&gt;. Are there papers or datasets of average CO&lt;sub&gt;2&lt;/sub&gt; concentrations down at &lt;em&gt;ground&lt;/em&gt; level (say 0-20 metres upwards from the ground), in the spaces between buildings - streets, parks and so on?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From what I've read, CO&lt;sub&gt;2&lt;/sub&gt; concentrations at higher levels are more temporally stable, but understate concentrations across the city; whereas monitoring stations down at street level give representative concentrations for that specific place, but are temporally highly variable, and comparisons between sites suggest that they are spatially highly variable too.&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="56" LastEditDate="2014-09-08T07:05:44.893" LastActivityDate="2014-12-13T08:22:29.243" Title="Are there any high-resolution urban CO2 concentration data sets?" Tags="|atmosphere|co2|pollution|urban-climate|land-surface|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2453" PostTypeId="2" ParentId="2451" CreationDate="2014-09-07T15:32:48.787" Score="7" Body="&lt;p&gt;Geology/Petrology has proposed some models for the origin of basalts which are based upon chemical evidence from rocks. Modern origin-models have been constrained by isotopic chemistry for some time. I do not claim to be current in this subject, but I believe the conclusions in this classic paper are still accepted as the most likely origin models.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://resolver.caltech.edu/CaltechAUTHORS:WASpnas79&quot; rel=&quot;nofollow&quot;&gt;Models of Earth Structure Inferred from Neodymium and Strontium Isotopic Abundances&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;G. J. Wasserburg and D. J. DePaolo&#xA;Proceedings of the National Academy of Sciences of the United States of America&#xA;Vol. 76, No. 8 (Aug., 1979), pp. 3594-3598&#xA;Published by: National Academy of Sciences&#xA;Article Stable URL: &lt;a href=&quot;http://www.jstor.org&quot; rel=&quot;nofollow&quot;&gt;http://www.jstor.org&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Free copies of this paper are available in several place from the Web. Here is the brief abstract. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;ABSTRACT: A simplified model of earth structure based on the Nd and Sr isotopic characteristics of oceanic and continental tholeiitic&#xA;  flood basalts is presented, taking into account the motion of crustal&#xA;  plates and a chemical balance for trace elements. The resulting&#xA;  structure that is inferred consists of a lower mantle that is still&#xA;  essentially undifferentiated, overlain by an upper mantle that is the&#xA;  residue of the original source from which the continents were&#xA;  derived.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="178" LastEditorUserId="725" LastEditDate="2014-12-13T20:29:48.333" LastActivityDate="2014-12-13T20:29:48.333" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2454" PostTypeId="1" AcceptedAnswerId="2463" CreationDate="2014-09-08T02:58:56.173" Score="17" ViewCount="4434" Body="&lt;p&gt;When I think of wind resistance, I always think of the friction co-efficient, in $\mathrm{ms^{-1}}$, because that's always the way that it was presented in highschool and undergraduate physics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But in land surface modelling, aerodynamic resistance (basically, how much the roughness of the surface slows air movement down), is defined inversely. For example, &lt;a href=&quot;http://www.iac.ethz.ch/edu/courses/master/modules/land-climate_interactions/HS2013/LCI13_lecture3.pdf&quot; rel=&quot;nofollow&quot;&gt;this presentation&lt;/a&gt; states on page 18 that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;$r_a$ = $f($wind speed, atmospheric stability, surface roughness$)$&lt;/li&gt;&#xA;  &lt;li&gt;$r_a$ decreases with increasing wind speed&lt;/li&gt;&#xA;  &lt;li&gt;$r_a$ increases with increasing stability&lt;/li&gt;&#xA;  &lt;li&gt;$r_a$ decreases with increasing surface roughness&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and then gives a bunch of examples in $\mathrm{sm^{-1}}$:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Surface type   ra (s.m^-1)&#xA;Ocean          200&#xA;Grass          70&#xA;Crops          20-50&#xA;Forest         5-10&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;To me, it seems really counter intuitive (&quot;resistance is higher over grass than over a forest&quot;?). Is the some benefit to defining resistances this way, or is this just some annoying historical mistake?&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="56" LastEditDate="2016-03-10T01:28:02.123" LastActivityDate="2016-03-10T01:28:02.123" Title="Why is aerodynamic resistance defined inversely?" Tags="|wind|atmosphere-modelling|land-surface-models|fluid-dynamics|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2455" PostTypeId="1" AcceptedAnswerId="2457" CreationDate="2014-09-08T06:03:03.787" Score="3" ViewCount="1706" Body="&lt;p&gt;As is reported on the major news networks, many glaciers and big icebergs are melting, which reportedly causes a tremendous increase in the amount of water vapor in the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now a lot of water vapor and the increasing heat from the sun powers stronger storms and greater inequalities in the distribution of water throughout the world. Therefore, there are more incidences of drought in some places and big flooding in others. I think it all relates back to the fact there are millions of tons more water vapor in the atmosphere. This, added with the Sun's heating, will make more intense storms. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is, given all the talk of global warming and instabilities in the weather why isn't the fact that there is a tremendous amount of extra water vapor in the atmosphere ever mentioned on the news or on other TV shows?&lt;/p&gt;&#xA;" OwnerUserId="855" LastEditorUserId="81" LastEditDate="2014-09-08T07:52:47.283" LastActivityDate="2014-12-14T05:52:10.323" Title="Regarding the melting glaciers and icebergs, why isn't the extra water vapor in the atmosphere mentioned in discussions of global warming?" Tags="|meteorology|atmosphere|global-warming|glacier|water-vapour|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2457" PostTypeId="2" ParentId="2455" CreationDate="2014-09-08T12:37:24.490" Score="13" Body="&lt;p&gt;Extra water doesn't mean extra water vapor. Even without this EXTRA water, the water vapor levels will increase, in the current warming world. As its the temperature rise that is making the water turn to vapor. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;As temperature rises, evaporation increases and more water vapour accumulates in the atmosphere. As a greenhouse gas, the water absorbs more heat, further warming the air and causing more evaporation. When CO&lt;sub&gt;2&lt;/sub&gt; is added to the atmosphere, as a greenhouse gas it has a warming effect. This causes more water to evaporate and warm the air to a higher, stabilized level. So the warming from CO&lt;sub&gt;2&lt;/sub&gt; has an amplified effect. Water vapor is infact the largest positive feedback in the climate system (Soden 2005). - &lt;a href=&quot;http://www.skepticalscience.com/water-vapor-greenhouse-gas-intermediate.htm&quot; rel=&quot;nofollow&quot;&gt;Skeptical Science&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Intensification of the water cycle hence, is a product of rise in temperature, rather than the water content. Of course we need water to evaporate, but the increase in the water content doesn't correlate to increased water vapor. It might play some role locally in small ponds and seasonal rivers which get dry during summers, but on a global scale with most of our evaporation occurring over oceans (86% of global evaporation), its not significant enough. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So coming to your question. First of all its not like water vapor is never mentioned - &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;As global temperatures rise, the atmosphere then holds more moisture ... Therefore there is more water vapor available to fall as rain, snow. - &lt;a href=&quot;http://thinkprogress.org/climate/2014/09/05/3563674/kashmir-flooding/&quot; rel=&quot;nofollow&quot;&gt;thinkprogress.org&lt;/a&gt; - September 5&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Global warming is moistening the atmosphere - &lt;a href=&quot;http://www.theguardian.com/environment/climate-consensus-97-per-cent/2014/aug/13/global-warming-moistening-the-atmosphere&quot; rel=&quot;nofollow&quot;&gt;The Guardian&lt;/a&gt; - August 13&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And if you notice, all the recent &lt;a href=&quot;http://www.reuters.com/article/2014/05/12/us-climatechange-antarctica-idUSKBN0DS1IH20140512&quot; rel=&quot;nofollow&quot;&gt;news about melting glaciers&lt;/a&gt; has been in connected to some recent developments and observations in form of published papers at reputed journals. NASA even conducted a &lt;a href=&quot;https://www.youtube.com/watch?v=hM7YOmyo2wg&quot; rel=&quot;nofollow&quot;&gt;press conference&lt;/a&gt; explaining their latest research, which led to a series of news articles on the topic. So, i'm quite sure if there are some significant developments in terms of water vapor research, it will make the news as well.  &lt;/p&gt;&#xA;" OwnerUserId="206" LastEditorUserId="725" LastEditDate="2014-12-14T05:52:10.323" LastActivityDate="2014-12-14T05:52:10.323" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2458" PostTypeId="2" ParentId="2455" CreationDate="2014-09-08T13:11:57.557" Score="13" Body="&lt;p&gt;Your reasoning is a bit flawed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The immediate effect of melting of the ice sheet is to add a small amount of water to the oceans (here small is relative to the huge amount of water already in the oceans). Over time, this small effect will result in sea level rise, currently estimated to be a rise of 50 to 200 centimeters by the end of this century.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At any one spot over the ocean, the rate at which water evaporates is a function of&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The surface temperature of the water,&lt;/li&gt;&#xA;&lt;li&gt;The surface temperature of the air,&lt;/li&gt;&#xA;&lt;li&gt;The humidity content of the air, and&lt;/li&gt;&#xA;&lt;li&gt;Surface winds.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Evaporation rate increases with increased air and water surface temperature, decreases as the relative humidity increases. Very calm air results in a thin layer of fully saturated air just above the water. This thin layer diffuses into the atmosphere as a whole. Diffusion is a slow process. A slight wind significantly increases transport from that surface layer. An even stronger wind keeps that surface layer from forming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Integrating this local evaporation rate over all the waters of the Earth results in a global evaporation rate. Global warming on average increases both air and water temperatures, thereby increasing the evaporation rate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Melting of the ice sheets does result in sea level rise, which in turn increases the surface area of the oceans, which in turn increases the global evaporation rate. This is a rather small effect compared to that of global warming. The sea level rise at any point in time is rather small. It only becomes significant on multi-decadal time scales. Moreover, even a two meter rise in sea level won't increase the surface area of the oceans by that much. Melting of all of the ice over Greenland and Antarctica most certainly would, but that won't be a problem for many hundreds of years. The immediate problem is what happens over the next 85 years or so, to the end of this century.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-09-08T13:11:57.557" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="2459" PostTypeId="1" AcceptedAnswerId="2465" CreationDate="2014-09-08T15:28:50.600" Score="11" ViewCount="2516" Body="&lt;p&gt;I was looking at a depth profile of a segment of the Atlantic Ocean. What is the relationship between dissolved oxygen and nitrate? When nitrate is high, dissolved oxygen is low and vice versa. I've been trying to work out why this is, but I'm drawing a blank.&lt;/p&gt;&#xA;" OwnerUserId="850" LastEditorUserId="725" LastEditDate="2014-12-14T05:49:54.497" LastActivityDate="2014-12-14T05:49:54.497" Title="Looking at ocean depth/latitude profiles of dissolved oxygen and nitrate. Why is dissolved oxygen low when nitrate is high?" Tags="|oceanography|geochemistry|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2460" PostTypeId="1" CreationDate="2014-09-08T15:31:08.820" Score="12" ViewCount="5116" Body="&lt;p&gt;The evaporation from a lake is to be calculated by the water balance method.   Inflow to the lake occurs through three small rivers, A, B and C.   The outflow occurs through the river D.   Calculate the evaporation from the lake surface during summer (May – August) if the water level was &lt;code&gt;+571.04 m&lt;/code&gt; on May 1 and &lt;code&gt;+571.10 m&lt;/code&gt; on August 31.   The lake surface area is 100 km$^2$.   The precipitation P during the period was 100 mm. Average inflows and outflow are given below:          &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;              River      Catchment(km2) Average Q(m3/s)&#xA;                A             150        15&#xA;                B             120        20&#xA;                C             130        17&#xA;                D                        45&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;This is the way I have attempted it:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Total Inflow ( by A, B, C) $= 52\ \mathrm{m^3/s}$.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Outflow (by D, assuming that D is fed by the lake) $= 45\ \mathrm{m^3/s}$.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Inflow - Outflow = Change in storage (which is in turn change in elevation × area)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Net Inflow into the lake = Inflow by 3 rivers + Precipitation&#xA;$$                           &#xA;= (52\ \mathrm{m^{3}/s} \times 122 \times (30\ \mathrm{days}+31+30+31)\times24\times60\times60 + 0.1\ \mathrm{m}\times100\times10^3 \mathrm{m}^2)&#xA;$$&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Total Outflow = Outflow + Evaporation&#xA;$$&#xA;                = (45\times122\times24\times60\times60 + E),&#xA;$$&#xA;where E is the component to be found.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Change in storage = Change in elevation × Area&#xA;$$&#xA;                  = (571.10 - 571.04)\times100 \times 10^6 E = 0.68\ \mathrm{m}&#xA;$$&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="858" LastEditorUserId="725" LastEditDate="2014-12-14T05:48:21.607" LastActivityDate="2023-06-28T17:01:55.813" Title="Lake inflow-outflow problem" Tags="|hydrology|homework|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2461" PostTypeId="2" ParentId="2449" CreationDate="2014-09-08T15:53:34.057" Score="8" Body="&lt;p&gt;I haven't been able to find any particular references which hold themselves out as the origin of $q$ as the symbol of choice for specific humidity, but the origin of the term &quot;specific humidity&quot; itself appears to have been in an 1884 article by Dr. W. von Bezold, translated into English and published in the &lt;a href=&quot;http://books.google.com/books?id=dEcWAAAAYAAJ&amp;amp;lpg=PA315&amp;amp;ots=-9iYTtreqm&amp;amp;dq=von%20bezold%20%22specific%20humidity%22&amp;amp;pg=PA327#v=onepage&amp;amp;q=von%20bezold%20%22specific%20humidity%22&amp;amp;f=false&quot;&gt;Smithsonian Miscellaneous Collections (Vol. 51)&lt;/a&gt; in 1910, and is defined therein as a &lt;strong&gt;quantity&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the quantity of vapor contained in the unit mass of moist air which can be conveniently called the &quot;specific humidity&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(p.327)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At that time, $q$ was not used, but instead von Bezold chose $y$ as the symbolic representation of specific humidity in his subsequent equations:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;$y$ the specific humidity or the quantity of vapor in a unit mass of moist air expressed in the fractional parts of this unit.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(p.328)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first appearance of $q$ as a symbol for specific humidity that I've found is in Chapter 5 of &lt;a href=&quot;http://books.google.com/books?id=bUQrAAAAYAAJ&amp;amp;lpg=PA133&amp;amp;ots=NbDGwc6zCj&amp;amp;dq=%22specific%20humidity%20q%22&amp;amp;lr&amp;amp;pg=PA151#v=onepage&amp;amp;q=%22specific%20humidity%20q%22&amp;amp;f=false&quot;&gt;Physics of the Earth, Vol. 1&lt;/a&gt; (p. 151), published in 1931. Here, the author uses $q$ to mean specific humidity as though it is common knowledge, using it in equations before even defining it for the reader:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This makes $q$ a readily determined and quite conservative characteristic of any unsaturated air mass.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Followed a few sentences later by:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The relative humidity $f$ together with the specific humidity $q$ and absolute humidity $\rho_{w}$ are the quantities commonly used as measures of the moisture content of the atmosphere.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(p.137)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This 1931 reference is likely not the earliest use of $q$ to mean specific humidity, but is the earliest I was able to uncover. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, it would seem that the use of $q$ as a commonly accepted symbolic representation of specific humidity originated sometime between 1884 and 1931. It seems quite plausible that, given the use of the word &quot;quantity&quot; in defining the term originally (and in later references that I'm unable to add links for), the choice of $q$ as the symbol for specific humidity finds its source in this definition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Additional reference: Temperature inversions in relation to frosts, McAdie, Alexander, Cambridge, 1915. (p.5) (Full text at Hathi Trust)&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="857" LastActivityDate="2014-09-08T15:53:34.057" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2462" PostTypeId="1" AcceptedAnswerId="2474" CreationDate="2014-09-06T14:17:58.177" Score="10" ViewCount="755" Body="&lt;p&gt;I have this construction site right outside my house, which I would like to give you some geographical background about before asking my question. Have a picture first though &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/fs1sc.jpg&quot; alt=&quot;Construction Site&quot;&gt;&#xA;&lt;br/&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There used to be industrial buildings of red clay bricks like the piece of wall still remaining. These walls, however, had a white stone facade around them so I'm not too sure the wall still standing was indeed part of the structure before demolition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The city I live in is Dresden, Germany and the district I live in was a major bomb dropping zone during WWII. For some reason in my district they decided to just let some walls of otherwise vanished old structures be and use them to mark estate borders, or to just be there really, which looks quite beautiful in some cases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seeing this construction site I cannot help but notice this black layer of earth under what seems to be a layer of rubble. Even though its not that noticeable on the left side, its continuous throughout the hole and starts appearing at the same height. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I said before, this area used to be exposed to heavy bombardment. So now I'm wondering if that might be the &quot;fire layer&quot; where the excessive heat hast left its mark in the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or is it, perhaps, a natural occurrence in slightly deeper depths, for the soil to turn that dark?&lt;/p&gt;&#xA;" OwnerUserId="871" OwnerDisplayName="Spraygun" LastActivityDate="2014-09-10T17:33:56.840" Title="Why is a layer of the subsoil so dark on this construction site?" Tags="|soil|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2463" PostTypeId="2" ParentId="2454" CreationDate="2014-09-08T21:02:44.373" Score="16" Body="&lt;p&gt;It's partly historical, partly point-of-view, but it's not a mistake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The friction coefficient emphasises the effect of the surface on a property of the boundary layer, i.e., greater surface friction slows the near-surface wind more.  Aerodynamic resistance emphasises the effect of the boundary layer on surface-atmosphere exchange, i.e., greater mixing yields a lower resistance to evaporation.  Note that it's evaporation not advection that's being resisted.  You could turn the confusion around and argue that friction coefficient is a counter intuitive term: if there's more friction, why does evaporation increase?  This would be making the same category error.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Historically (IIRC) the electrical circuit metaphor was introduced by Penman and Schofield (1951) in an early modification of the Penman evapotranspiration equation to account for how vegetation limits the transpiration rate.  The original Penman equation is often quoted using aerodynamic conductance (or friction velocity or friction coefficient), i.e., a quantity using the the $m s^{-1}$ units that you're used to.  This is a natural choice for micrometeorologists trying to understand the bulk mass transfer properties of the turbulent boundary layer because it can be calculated from the boundary layer quantities that they measure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once you start introducing other surface effects on evaporation it's not really appropriate to extend the analogy of a turbulent fluid friction velocity down from the boundary layer to vegetation stomata, roots and the soil.  So we use the electrical metaphor instead, in which case it becomes &lt;em&gt;slightly&lt;/em&gt; simpler to describe the system using resistances rather than conductances.  In the first instance it was just a case of calculating the total system resistance by adding a stomatal resistance to the aerodynamic resistance:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$E = \frac{\rho}{r_s+r_a}\left(q_{sat} - q_a\right) = \frac{\rho}{r_t}\left(q_{sat} - q_a\right)$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can express this as conductances, but it's not as neat:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$E = \frac{g_a g_s \rho}{g_a+g_s}\left(q_{sat} - q_a\right)$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see in the later slides of the presentation you linked to that these resistance networks have got progressively more complex, so nowadays this neatness point might be moot.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Penman and Schofield (1951) Some physical aspects of assimilation and transpiration, Symp. Soc. Exper. Biol., 5, 115-129.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2014-09-08T21:02:44.373" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2464" PostTypeId="2" ParentId="2460" CreationDate="2014-09-09T13:29:40.250" Score="9" Body="&lt;p&gt;Everything you did looks reasonable.  There is one error in the 'net inflow into lake' line where you take the area of the lake to be $100\cdot10^3\ \text{m}^2$ instead of $100\cdot10^6\ \text{m}^2$, but that might just be a typo.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, this type of problem is much easier to work (especially when you think you've made an error) by keeping everything symbolic.  For your problem I would define the variables&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$i$: inflow into the river in $\frac{\text{m}^3}{\text{s}}$&lt;/li&gt;&#xA;&lt;li&gt;$o$: outflow from the river in $\frac{\text{m}^3}{\text{s}}$&lt;/li&gt;&#xA;&lt;li&gt;$r$: inflow from rain in $\text{m}$&lt;/li&gt;&#xA;&lt;li&gt;$e$: evaporation in $\text{m}^3$&lt;/li&gt;&#xA;&lt;li&gt;$\Delta h$: change in height of the lake in $\text{m}$&lt;/li&gt;&#xA;&lt;li&gt;$A$: area of the lake in $\text{m}^2$&lt;/li&gt;&#xA;&lt;li&gt;$\Delta t$: time period in $\text{s}$&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The equilibrium equation is then &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\text{sum of inflows}-\text{sum of outflows}=\text{change in storage}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;which is written in terms of the defined variables as&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$i\ \Delta t+r\ A-o\ \Delta t-e=\Delta h\ A.$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can check that this equation at least makes sense in terms of units by observing that all of the terms have units of volume, i.e. $\text{m}^3$.  Finally, you can rearrange the equation to solve for the variable of interest;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$e=(i-o)\Delta t+(r-\Delta h)A.$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At this point you can plug in the numbers. &lt;/p&gt;&#xA;" OwnerUserId="53" LastEditorUserId="53" LastEditDate="2014-09-09T13:42:46.663" LastActivityDate="2014-09-09T13:42:46.663" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2465" PostTypeId="2" ParentId="2459" CreationDate="2014-09-09T13:32:26.180" Score="9" Body="&lt;p&gt;In general the relationship between dissolved oxygen and nitrate is complex. While in areas of water mass formation, especially in the Arctic and Antarctic Oceans, nutrient concentration and dissolved oxygen can be high, water mass evolution and biological activity can rapidly modified these concentration. The relationship is affected by several factors including: 1) the age of the water mass: the &quot;older&quot; the water mass (longer time since in equilibrium with atmospheric oxygen), the lower the dissolved oxygen concentration; and 2) the proximity to primary productive areas like the surface: the higher the primary production, the lower the nitrate concentration.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In some parts of the interior of the Atlantic Ocean, the water masses present (North Atlantic Deep Water, Antarctic Bottom Water) are pretty old and haven't been in contact with the surface layers for a while, so their oxygen concentration is high while they remain nutrient rich. The water masses in the surface layers have recently been in contact with the atmosphere and thus have a high oxygen concentration. Meanwhile, by being near the surface they are subject to primary production that tends to rapidly consume the nutrients (like nitrate). The relationship is highly variable spatially specially near the coastal regions, where processes like upwelling/downwelling can rapidly modified nutrient and oxygen concentrations.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-09-09T13:32:26.180" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2466" PostTypeId="2" ParentId="2454" CreationDate="2014-09-09T15:18:28.017" Score="10" Body="&lt;p&gt;This is a good question, and the answer is, aerodynamic resistance is &lt;strong&gt;not&lt;/strong&gt; defined inversely. It is rather, defined in a context that is often misinterpreted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In your question, you state that aerodynamic resistance is basically how much the roughness of the surface slows air movement down. This statement is not correct, and it seems to stem from the misinterpretation of context. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A monograph by De Groot (1963) also shows that molecular transfer processes have the general form analogous to the electric circuit shown by @Deditos' answer:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;Flux = \dfrac{Force}{Resistance}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is also true for air-sea and other general fluid-fluid interfaces. Flux is the transfer of a quantity (say, momentum, enthalpy, mass, etc.) through the interface and the associated boundary layers (say, air, water, canopy, soil, etc.). In the electric circuit analogy, force has the character of potential gradient and resistance has that of the inverse conductivity. The important point to be made here is that resistance is &lt;strong&gt;not&lt;/strong&gt; resistance of interface to the aerodynamic flow - what we would intuitively imagine as friction or stress. It is in fact, &lt;strong&gt;resistance of the interface to the forcing&lt;/strong&gt;. In case of momentum, this means that given equal forcing, higher resistance yields lower flux. Thus, lower resistance translates to rougher surface. This is why forest has lower resistance values than grass or open ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Example: Given equal forcing, rougher surface results in higher stress compared to smoother surface. It can be said that the rougher surface is &quot;more permitting&quot;, or &quot;less resistant&quot; of momentum flux.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the electric circuit analogy, &lt;em&gt;Flux&lt;/em&gt;, &lt;em&gt;Force&lt;/em&gt; and &lt;em&gt;Resistance&lt;/em&gt; are symbolic, conceptual entities. Force is not necessarily in $\rm N$, and may be a temperature or humidity gradient like it is given on slide 16 in the presentation you linked. Resistance may thus take different formulations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that nowadays, in both modeling and theory, we often use exchange coefficients to characterize momentum $(C_{D})$ and enthalpy $(C_H$, $C_E)$ fluxes through the interface, which act as conductivity and not resistance. For example, in case of momentum:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\boldsymbol{\tau} = \rho C_{D}|\mathbf{U}|\mathbf{U}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\boldsymbol{\tau}$ $(\mathrm{N/m^{2}})$ is vertical flux of horizontal momentum (wind stress), $\rho$ $(\mathrm{kg/m^{3}})$ is air density and $\mathbf{U}$ $(\mathrm{m/s})$ is wind vector at some reference height above the surface. $C_{D}$ (non-dimensional) has different values depending on the surface properties.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In that particular presentation that you linked in your question, it is not clear to me why resistance $r_a$ has units of $\mathrm{s\ m^{-1}}$. For sensible and latent heat flux $\mathrm{ (W / m^2) }$ formulations on slide 16, the units don't quite work out, but it is possible that the equations shown were more illustrative than exact. Because bulk flux formulae are most often based on theoretical, empirical and dimensional grounds, $r_{a}$ can be defined in various dimensions (units) depending on the bulk flux formulation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reference:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;De Groot, S. R. Thermodynamics of Irreversible Processes. North Holland Publishing Co., 1963.&lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="725" LastEditDate="2014-12-13T16:00:30.587" LastActivityDate="2014-12-13T16:00:30.587" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2467" PostTypeId="2" ParentId="2459" CreationDate="2014-09-09T18:06:32.547" Score="7" Body="&lt;p&gt;The chemical reactions responsible for the decomposition of biological organisms after they die releases soluble nitrogen compounds and consumes oxygen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Decomposing organic matter tends to sink. Although it may be recycled several times, eventually is sinks out of the photic zone. Decomposition consumes oxygen and releases nitrogen into the relatively closed deep water mass making it relatively oxygen-poor and nitrogen-rich.    &lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-09-09T18:06:32.547" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2468" PostTypeId="1" AcceptedAnswerId="2475" CreationDate="2014-09-09T18:22:15.233" Score="2" ViewCount="16903" Body="&lt;p&gt;This may be a slightly unusual question. I know it wouldn't be possible, but what would the short and long term effects be, if a large (say, 1 mile diameter) round hole appeared, and went straight through the center of the earth, through the crusts on both sides. Would it be different if they opened on land, rather than ocean?&lt;/p&gt;&#xA;" OwnerUserId="611" LastEditorUserId="725" LastEditDate="2016-01-22T00:55:40.683" LastActivityDate="2022-11-27T07:55:15.110" Title="Hypothetically, what would happen to the earth if a large hole was drilled through the center?" Tags="|geology|hypothetical|drilling|" AnswerCount="2" CommentCount="15" ContentLicense="CC BY-SA 3.0" />
  <row Id="2469" PostTypeId="2" ParentId="2459" CreationDate="2014-09-10T04:12:24.050" Score="6" Body="&lt;p&gt;Because the bacteria that converts the waste (ammonia) to nitrates consumes oxygen. So its more a matter of oxygen depletion rather than an initial lack of oxygen. &lt;/p&gt;&#xA;" OwnerUserId="863" LastActivityDate="2014-09-10T04:12:24.050" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2470" PostTypeId="2" ParentId="2455" CreationDate="2014-09-10T04:25:00.347" Score="2" Body="&lt;p&gt;To the contrary that's how many people explain the historical rain &amp;amp; snowfall events around the world. As the poles melt more water is absorbed into the atmosphere, concentrated in the jet streams and eventually dumped thousands of miles away.&lt;/p&gt;&#xA;" OwnerUserId="863" LastActivityDate="2014-09-10T04:25:00.347" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2471" PostTypeId="2" ParentId="2300" CreationDate="2014-09-10T04:59:03.363" Score="2" Body="&lt;p&gt;IRI's (Ionospheric Research Instrument or HF Radio Transmitter) can be used to excite specific areas of the ionosphere. The resulting heat creates a high pressure system that can be then be used to push the jet stream or prevent it from moving. This is the type of equipment that world powers had in mind when they signed the Kyoto Protocol 50 years ago (banning weather warfare). Its also what the USAF had in mind when they wrote the manual &quot;Weather as a Force Multiplier. Owning the Weather by 2025&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the USAF and the Defense Advanced Research Projects Agencies (DARPA) very own website, HAARP is designed to excite the ionosphere. This results in a super heated mass that expands outward, and therefore creating a high pressure system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;High pressure systems whether natural or man made have a direct impact on the path that a weather system will take.  The jet stream will take the least path of resistance for example. When it encounters a high pressure system it is forced to take a different path. A high pressure system acts like the bumpers on a pin ball machine. This isn't a theory, it is meteorological science.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whether or not the system is used for good or evil is another, unrelated topic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I provided several references to credible sources that explain this technology in my previous answer.  I will add to the list as you requested and hope that the additional references and citations adequately address your concerns. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;USAF manual “Weather as a force Multiplier. Owning the Weather by 2025” can be found here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://csat.au.af.mil/2025/volume3/vol3ch15.pdf&quot; rel=&quot;nofollow&quot;&gt;http://csat.au.af.mil/2025/volume3/vol3ch15.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;United States Patent # 4,686,605 can be viewed on the US Patent offices website and offers a full description of the capabilities of the system:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://patft.uspto.gov/&quot; rel=&quot;nofollow&quot;&gt;http://patft.uspto.gov/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The USAF’s official website that describes the installation has apparently been removed in anticipation of the planned disassembly of the installation. But archives of the website can still be found here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://archive.today/www.haarp.alaska.edu&quot; rel=&quot;nofollow&quot;&gt;http://archive.today/www.haarp.alaska.edu&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wikipedia's article on the topic can be found here: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/High_Frequency_Active_Auroral_Research_Program&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/High_Frequency_Active_Auroral_Research_Program&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And here's another article on Wikipedia that should illustrate the seriousness of weather warfare technologies and the precautions that various countries have taken to prevent abuse of the technology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Weather_modification&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/Weather_modification&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="863" LastEditorUserId="863" LastEditDate="2014-09-10T22:09:29.400" LastActivityDate="2014-09-10T22:09:29.400" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2473" PostTypeId="1" AcceptedAnswerId="2476" CreationDate="2014-09-10T05:34:12.063" Score="9" ViewCount="551" Body="&lt;p&gt;A schematic for the fluid mechanics of a volcano is represented below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/8Efof.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&lt;strong&gt;Graciously borrowed from Figure 1 of the reference cited below&lt;/strong&gt; &lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the caption of that figure:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;During explosive eruptions, bubble walls rupture catastrophically at the&#xA;  fragmentation surface. The released gas expands rapidly and magma ascent changes from a viscous melt with suspended bubbles to a gas flow with suspended magma fragments.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My assumption is that this boundary between the magma column and the steam above it is critical to the crystallization of the minerals to form the volcanic rock. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Does the composition of the volcanic rock change drastically according to the distance between the magma column and the mouth of the volcano at the time the rock is formed? &lt;/li&gt;&#xA;&lt;li&gt;(Or) do the rocks melt and recrystallize frequently as the boundary moves, only attaining their final composition before they are ejected into the air?  &lt;/li&gt;&#xA;&lt;li&gt;How important is the steam/air interface at the top of the volcano to the rock's formation?  &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I realize this is going to change based on the composition of the magma itself, but I'm looking for the behavior of an &quot;average&quot; rock species, though specific examples are great, too. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Reference:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Gonnermann, H.M. and Manga, M. (2007). The fluid mechanics inside a volcano. &lt;em&gt;Annu. Rev. Fluid Mech, 39&lt;/em&gt;, 321–56. &lt;a href=&quot;http://www.soest.hawaii.edu/GG/SYI/helge/pubs/gonnermann_manga_2007.pdf&quot; rel=&quot;noreferrer&quot;&gt;[PDF]&lt;/a&gt; &lt;a href=&quot;http://dx.doi.org/10.1146/annurev.fluid.39.050905.110207&quot; rel=&quot;noreferrer&quot;&gt;[DOI]&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="19" LastActivityDate="2014-12-03T18:38:52.360" Title="How does the composition of volcanic rock change as it makes its ascent towards the surface?" Tags="|volcanology|geochemistry|mineralogy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2474" PostTypeId="2" ParentId="2462" CreationDate="2014-09-10T17:33:56.840" Score="5" Body="&lt;p&gt;Regarding your question:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;So now I'm wondering if that might be the &quot;fire layer&quot; where the excessive heat hast left its mark in the ground.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The short answer is no. The layer seems to be about 1 meter thick. No bombardment related fire can cause blackening 1 meter deep.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, why is it &quot;black&quot;? First of all, it's not black. It's dark brown. I've seen black soils, and trust me - they are pitch black. There are several reasons for it. My best guess is that it's simply moist. You know how things appear darker when wet? Same here. My hint is the floor of the site. I'm guessing it's the same material, but it's drier so it looks lighter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are more reasons, some concerning the organic content of the soil (for example, peat - a highly organic black soil) or the mineral content of the soil (soil composed of high iron contents will also appear black).&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2014-09-10T17:33:56.840" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2475" PostTypeId="2" ParentId="2468" CreationDate="2014-09-10T17:58:25.223" Score="10" Body="&lt;p&gt;The best place to ask this question is going to be at xkcd: &lt;a href=&quot;http://what-if.xkcd.com/&quot; rel=&quot;noreferrer&quot;&gt;http://what-if.xkcd.com/&lt;/a&gt; but I will give it a shot.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not a geophysicist, but I'll try to give you a reasonable enough answer. &#xA;As you said, making such a hole is not possible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, let's try to think what if some magical force made a hole 1 km wide and then suddenly released it. This is what the Earth is made of:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/ast8H.jpg&quot; alt=&quot;The Earth&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(taken from here: &lt;a href=&quot;http://www.nature.com/nature/journal/v479/n7374/fig_tab/479480a_F1.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.nature.com/nature/journal/v479/n7374/fig_tab/479480a_F1.html&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The easiest part to explain will be to see what happens in the core. Both the inner and outer core are basically made out of impure iron. The liquid iron will just flow into itself and close the hole rather quickly (think about a similar hole in water). The solid iron is also ductile as there high pressures and temperatures, so it will also flow and close the hole. Think chocolate close to the melting temperature. It's still solid, but it moves. Probably some of the liquid iron will manage to flow into the hole of the solid iron, but it will then solidify because it will have to endure higher pressures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, what happens at the mantle? The lower mantle is also ductile and it will also flow under the pressure. You have to remember the the walls of the hole are under huge pressures - 24 to 136 GPa according to the figure. Some things may &quot;fall inside&quot;, but remember that it has to fall over hundreds of kilometers while the hole is only 1 km wide.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The upper mantle is where it becomes interesting. This is just thinking out loud though. The upper mantle is where magmas are being formed, and one of the reasons magma is formed is decompression. Usually this happens because of mid ocean spreading or mantle plumes, but removing one side of let's say a cube of rock is also going to decompress it somewhat. This may cause generation of magma. No worries though - I don't see any reason why it should rise to the surface. If anything at all, it's going to fall down through the hole (but not much, see above). Also, decompression may cause release of volatiles or gas, the most common being CO2 and H2O I guess, also H2S or SO2 depends exactly what is down there. Also, the movement of rocks in an area of the Earth that's not ductile anymore but rather brittle (&lt;a href=&quot;https://en.wikipedia.org/wiki/Lithosphere&quot; rel=&quot;noreferrer&quot; title=&quot;Lithosphere&quot;&gt;lithosphere&lt;/a&gt;) is sure to cause some earthquakes. Are there earthquakes going to be dangerous for anyone? I don't know.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would this hole look like if you peeked down? My guess that it will be filled with water. If this hole starts at the ocean, then the ocean will just flow inside and fill it. It is possible that some mega waves or tsunamis will accompany it. It will pour down until it either meets the closed rock, or just evaporates. Remember - it's pretty hot down there. It will evaporate and rise, then cool and starts raining down again and you will have a nice convective cell in the upper few kilometers of this hole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In contrast, if this was not in the ocean but rather on land, groundwater will fill it in. I guess most of the earth has groundwater (maybe except the large deserts, but even there some water exists) that will just flow inside and create a similar convective cell.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2014-09-10T17:58:25.223" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="2476" PostTypeId="2" ParentId="2473" CreationDate="2014-09-10T18:16:27.210" Score="7" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Does the composition of the volcanic rock change drastically according to the distance between the magma column and the mouth of the volcano at the time the rock is formed? &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The metal composition of the magma will not change drastically. By metal I mean the basic constituents of the rock: mostly silicon but also iron, calcium, aluminum, magnesium, etc. I will add that there are processes that can affect metal composition (chiefly mineral fractionation) but I think its influence is minor when you're talking the the uppermost part of the volcano where it erupts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What can and does change is the volatile composition. The magma is depleted of gases. Take for example a bottle of coke. When you open it, the CO&lt;sub&gt;2&lt;/sub&gt; bubbles out. The coke itself remains coke, but its chemistry changes a bit (and it tastes bad) because the CO&lt;sub&gt;2&lt;/sub&gt; is out. The magma may also change oxidation state. This, together with the volatile degassing may eventually affect the minerals that crystallise from the magma.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;(Or) do the rocks melt and recrystallize frequently as the boundary moves, only attaining their final composition before they are ejected into the air? &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No. Once a rock crystallises you are going to need quite a lot of energy to melt it again, and this is not a likely process to occur in a system open to the atmosphere where heat is free to leave the volcanic system.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2014-12-03T18:38:52.360" LastActivityDate="2014-12-03T18:38:52.360" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2478" PostTypeId="1" AcceptedAnswerId="2613" CreationDate="2014-09-12T01:00:50.827" Score="9" ViewCount="168" Body="&lt;p&gt;Recently, steinhardite was &lt;a href=&quot;http://wwwphy.princeton.edu/~steinh/steinhardtite.html&quot; rel=&quot;nofollow&quot;&gt;accepted&lt;/a&gt; as a new mineral by the International Mineralogical Association.  It's quite an interesting story in its own right. There's an interesting article in &lt;a href=&quot;http://www.newscientist.com/article/mg22329860.300-quasicrystal-quest-the-unreal-rock-that-nature-made.html&quot; rel=&quot;nofollow&quot;&gt;New Scientist&lt;/a&gt; about it, but it's paywalled.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The formula for steinhardite is $\ce{Al63Cu24Fe13}$.  It's an ultra-rare quasicrystal, at least partially because of the mixture of aluminum without oxygen, as I understand it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the critics (as quoted in the article)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... who promptly declared the possibility&#xA;  of the sample being natural as ‘‘impossible’’. His&#xA;  concern was not the degree of perfection but,&#xA;  rather, the baffling presence of metallic Al in&#xA;  cupalite, khatyrkite and in the icosahedral&#xA;  quasicrystal phase. Metallic Al has a remarkably&#xA;  strong affinity for O, such that it could not&#xA;  possibly form naturally on the surface of the&#xA;  Earth, he argued ... he amended the conclusion to allow for the&#xA;  improbable possibility that it could have formed&#xA;  under the intense heat and pressure that exist near&#xA;  the core mantle boundary or in a high impact&#xA;  collision of meteors in space. [1]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The core/mantle boundary is obviously rife with lots of chemical interactions, but what is it exactly about the conditions that prevents aluminum from oxidizing?  Is it just physical pressure or the presence of other gases?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's the obvious fact that the aluminum isn't exposed to the atmosphere, but my (limited) understanding is that oxygen is plentiful in combination with other elements like silicon.   &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Reference:&lt;/p&gt;&#xA;  &#xA;  &lt;ol&gt;&#xA;  &lt;li&gt;Bindi, L. &amp;amp; Steinhardt, P.J. (2014) The quest for forbidden crystals. &lt;em&gt;Mineralogical Magazine, 78&lt;/em&gt;(2), 467–482. &lt;a href=&quot;http://dx.doi.org/10.1180/minmag.2014.078.2.15&quot; rel=&quot;nofollow&quot;&gt;[DOI]&lt;/a&gt; &lt;a href=&quot;http://minmag.geoscienceworld.org/content/78/2/467.full.pdf&quot; rel=&quot;nofollow&quot;&gt;[PDF]&lt;/a&gt; (seems to be freely available) &lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="19" LastEditorUserId="725" LastEditDate="2014-12-14T06:07:52.460" LastActivityDate="2014-12-14T06:07:52.460" Title="What makes the conditions at the core/mantle boundary ideal for aluminum to combine with other elements besides oxygen?" Tags="|geophysics|geochemistry|mineralogy|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2479" PostTypeId="2" ParentId="2437" CreationDate="2014-09-12T14:21:41.850" Score="9" Body="&lt;p&gt;+1 for GPlates, but if you happen to be an ArcGIS user (I was once, but I'm better now), then the &lt;a href=&quot;http://www.paleogis.com/&quot;&gt;PaleoGIS plugin&lt;/a&gt; is pretty good. Skimming through their material I can't tell if there's any other way to run it, but I don't think there is.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2014-09-12T14:21:41.850" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2480" PostTypeId="2" ParentId="265" CreationDate="2014-09-12T18:10:34.597" Score="14" Body="&lt;p&gt;It's not a healthy distinction, but in petroleum geoscience one can characterize the distinction around the sort of data people look at. Geophysicists are into seismic, sonic logs, gravity and magnetics data, electromagnetic (resistivity) data,... and anything to do with computers. Geologists meanwhile are into core, outcrop, gamma-ray and density logs, stratigraphy, tectonic reconstructions,... and anything to do with coloured pencils. Of course, they're both working towards the same thing: a model of the earth and its history.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your question also made me think of a couple of Twitter conversations, both started by &lt;a href=&quot;http://www2.kent.edu/geology/faculty/~crowan5/&quot; rel=&quot;noreferrer&quot;&gt;Chris Rowan at Kent State&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;I'd be interested in your answers to q I'm exploring in my lecture this morning: what makes geophysics distinct from geology? &lt;a href=&quot;https://twitter.com/Allochthonous/status/291174941494218753&quot; rel=&quot;noreferrer&quot;&gt;Read thread.&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Why I sometimes get antsy when people call me a geophysicist. Ultimately, I favour reality over fancy computer plots. &lt;a href=&quot;https://twitter.com/Allochthonous/status/421494185737191424&quot; rel=&quot;noreferrer&quot;&gt;Read thread.&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The first one of these prompted me to draw this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/FjS92.png&quot; alt=&quot;The difference between geology and geophysics&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I make no claims to the accuracy or seriousness of this facile comparison.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2014-09-12T18:10:34.597" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2481" PostTypeId="1" AcceptedAnswerId="6811" CreationDate="2014-09-12T21:42:31.973" Score="14" ViewCount="172" Body="&lt;p&gt;&lt;a href=&quot;http://goo.gl/maps/ZqBaI&quot;&gt;Contwoyto Lake&lt;/a&gt; is a large lake in northwestern Nunavut.  Descriptions of it say that its primary outlet leads to Bathurst Inlet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does the lake also have an outlet that leads to Chantrey Inlet, reaching the sea 300 miles to the east?&lt;/p&gt;&#xA;" OwnerUserId="875" LastEditorUserId="124" LastEditDate="2014-09-13T14:54:27.980" LastActivityDate="2015-10-29T16:24:34.457" Title="Does Contwoyto Lake empty into both Bathurst Inlet and Chantrey Inlet?" Tags="|rivers|geography|canada|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2482" PostTypeId="1" AcceptedAnswerId="2483" CreationDate="2014-09-13T19:05:53.303" Score="11" ViewCount="3463" Body="&lt;p&gt;Various companies offer &quot;volcanic crystals&quot; or &quot;volcanic rock&quot; available in small mesh bags for odor control.  The best description I have found is that these are made up largely of Zeolites.  All of these manufacturers suggest that the rocks will trap odors and to just recharge the rocks every 6 months by putting it out in direct sunlight.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This sounds like witchcraft!  Can someone explain why putting the rocks in sunlight (versus other light) recharges them and makes them effective at trapping odors again?  How does the light &quot;release&quot; the odor?  Is it the heat of the sunlight, or could this be used in the winter as well?&lt;/p&gt;&#xA;" OwnerUserId="877" LastActivityDate="2018-06-08T13:52:37.380" Title="Zeolites, odor control, and the witchcraft of sunlight" Tags="|geology|volcanology|rocks|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2483" PostTypeId="2" ParentId="2482" CreationDate="2014-09-13T21:55:48.020" Score="15" Body="&lt;p&gt;Zeolites are very similar to clays, with one key difference. The molecular structure of clays is rather compact. In contrast, the molecular structure of zeolites has tiny molecular-sized holes, and these holes are wont to connect. The result is a porous, tunnel-filled structure at the molecular level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The resulting tunnels make zeolites very good at absorbing substances that fit very nicely in those tunnels. What those substances are depends on the zeolite. There are a large number of naturally occurring zeolites, and even larger number of manufactured zeolites. Which zeolite absorbs what substance depends very much on the nature of the holes in the zeolite. As an example, the International Space Station uses a particular kind of zeolites (&quot;zeolite 5A&quot;) to selectively absorb carbon dioxide from the breathing atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Zeolites would need to be discarded after becoming saturated if all they did was absorb stuff. That's not the case. It's rather easy to make zeolites relinquish the stuff they have absorbed because the absorption mechanism is rather weak. All it takes is a smallish amount of energy. Zeolites used in industrial settings are subjected to heat, noxious chemicals,or both to make them relinquish the stuff they have absorbed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to having a large number of industrial uses, zeolites have apparently become attractive to the &quot;all natural&quot; crowd. (I suspect the larger number of &quot;non-natural&quot; zeolites are verboten amongst this crowd.) Exposing zeolites to sunlight means they absorb heat and ultraviolet light. This is indeed one way to make zeolites reject whatever has been absorbed. That's not very efficient; it would be much more efficient to bake those zeolites and/or expose them to a series of caustic chemical baths. However, that wouldn't play well with the &quot;all natural&quot; crowd.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-09-13T21:55:48.020" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2484" PostTypeId="1" AcceptedAnswerId="2610" CreationDate="2014-09-14T04:37:50.477" Score="9" ViewCount="168" Body="&lt;p&gt;The image below (borrowed from [#1]) shows the topology of the seismometers around the volcano Stromboli.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/B5cUT.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the text, they explain the following:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The seimometers were set on the&#xA;  flanks of the volcano, forming three rings around the crater&#xA;  area at different altitudes (top, middle and bottom ring indicated&#xA;  on the map with the letters T, M, B, respectively). The&#xA;  distances of the stations from the crater zone ranged from 0.3&#xA;  to 2.2 km.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;What are the factors that dictate a given topology for seismometer placement around a volcano?  There are probably some obvious rules of thumb in terms of placing them at different elevations and placing them outside of any lava paths or areas showered with debris.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Is the soil around the volcano homogeneous enough to produce a response that radiates outward at the same rate?  If not, shouldn't the sensors be placed in concentric circles to capture the arrival times for the waves?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Reference:&lt;/p&gt;&#xA;  &#xA;  &lt;ol&gt;&#xA;  &lt;li&gt;De Lauro, E,De Martino, S, Falanga, M, and Palo, M. (2006). Statistical analysis of Stromboli VLP tremor in the band [0.1-0.5]Hz: some consequences for vibrating structures. &lt;em&gt;Nonlin. Processes Geophys., 13&lt;/em&gt;, 393–400. &lt;a href=&quot;http://dx.doi.org/10.5194/npg-13-393-2006&quot;&gt;[DOI]&lt;/a&gt; &lt;a href=&quot;http://www.nonlin-processes-geophys.net/13/393/2006/npg-13-393-2006.pdf&quot;&gt;[PDF]&lt;/a&gt; (freely available)&lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="19" LastActivityDate="2014-10-10T21:34:33.900" Title="What are the factors that dictate a given topology for seismometer placement around a volcano?" Tags="|geophysics|seismology|volcanology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2485" PostTypeId="1" AcceptedAnswerId="2488" CreationDate="2014-09-15T05:05:13.027" Score="16" ViewCount="360" Body="&lt;p&gt;I am looking for a believable explanation of the Red Sea Crossing in the Bible. This would involve either strong winds(which is mentioned in the Bible) or plate tectonics which could cause land to rise up and fall again.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My problem with wind is that I know of no incident where strong winds parted a sea --- even one as shallow as the Red Sea which is, as far as I know as low as 50m in some areas. Winds always move inland not parallel to the coast. Tidal waves and tsunamis always crash into the land not part the sea. Unless I am mistaken.....&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plate movement that both raised and lowered the seabed seems more likely and the Red Sea sees a lot of earthquakes. I've heard the surface area can be crossed in as little as 4 hours. Does anyone know of an example where the land was both raised and lowered in an earthquake, high and low enough to create both a crossing and drowning ?&lt;/p&gt;&#xA;" OwnerUserId="880" LastEditorUserId="880" LastEditDate="2014-09-16T03:31:17.633" LastActivityDate="2014-12-14T06:01:12.910" Title="Potential explanations of Red Sea crossing" Tags="|ocean|earthquakes|sea-level|wind|waves|" AnswerCount="1" CommentCount="3" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2486" PostTypeId="1" CreationDate="2014-09-15T07:12:48.120" Score="11" ViewCount="6566" Body="&lt;p&gt;Is the atmosphere getting more dense with various gases, car pollution (200 million cars just in North America), factory pollution, more water vapor and denser cloud cover? If so could a &quot;thicker&quot; atmosphere act like a lens and magnify the Sun's rays to an intensity a higher than what it should be?&lt;/p&gt;&#xA;" OwnerUserId="855" LastEditorUserId="192" LastEditDate="2014-09-15T14:57:15.307" LastActivityDate="2021-07-10T07:33:09.850" Title="Is the atmosphere becoming thicker?" Tags="|atmosphere|" AnswerCount="3" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="2487" PostTypeId="1" AcceptedAnswerId="3094" CreationDate="2014-09-15T09:00:12.233" Score="11" ViewCount="180" Body="&lt;p&gt;I have read the question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/218/what-generates-the-microseism&quot;&gt;What generates the microseism?&lt;/a&gt; and it's accompanying answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In [#1, cited below], they use the azimuth values of seismographic activity on the flanks of the volcano Stromboli to discern where this microseismic &quot;noise&quot; is coming from:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The behaviour of polarisation at the east flank lets us suppose&#xA;  that the microseismic noise comes from this direction.&#xA;  This is the direction of the Scirocco wind (south, southeast&#xA;  direction) that blows on Stromboli during summer season.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, according the other answer on the site, these low frequency oscillations are due to the wind's effect on the waves of the ocean.  In the initial question that sparked the answer, it was cited the frequency of these ocean waves was 0.2 Hz, which is in the 0.1-0.5 Hz region that the Stromboli researchers were looking at.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The whole crux of the Stromboli paper was that the microseismic events (volcanic and non-volcanic) were enough to confound the separation of the tremor signals into independent components  These researchers were using independent component analysis (ICA) and were able to pull a 0.2 Hz and a 0.4 Hz component out of the mixture (likely corresponding to the 0.2 Hz ocean wave energy mentioned in the other question). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/NMaAz.png&quot; alt=&quot;enter image description here&quot;&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The remaining energy in the microseismic range (which can be seen in the first two components) is preventing further separation of the other components of the microseismic activity .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Stromboli has a constant tremor due to its ongoing activity, but have there been efforts elsewhere to suss out which of the microseismic activities are from sources in the ocean versus those coming from intermittent volcanic tremors?  Could this be achieved by using a combination of sensors, some in the ocean and some on land, or is this type of analysis not really useful?&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Reference:&lt;/p&gt;&#xA;  &#xA;  &lt;ol&gt;&#xA;  &lt;li&gt;De Lauro, E,De Martino, S, Falanga, M, and Palo, M. (2006). Statistical analysis of Stromboli VLP tremor in the band [0.1-0.5]Hz: some consequences for vibrating structures. &lt;em&gt;Nonlin. Processes Geophys., 13&lt;/em&gt;, 393–400. &lt;a href=&quot;http://dx.doi.org/10.5194/npg-13-393-2006&quot; rel=&quot;nofollow noreferrer&quot;&gt;[DOI]&lt;/a&gt; &lt;a href=&quot;http://www.nonlin-processes-geophys.net/13/393/2006/npg-13-393-2006.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;[PDF]&lt;/a&gt; (freely available)&lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="19" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-12-21T03:21:58.390" Title="What efforts have been made to separate the microseismic events related to wind-related ocean waves from the components of volcanic origin?" Tags="|geophysics|ocean|seismology|volcanology|ocean-currents|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2488" PostTypeId="2" ParentId="2485" CreationDate="2014-09-15T13:58:58.383" Score="17" Body="&lt;p&gt;To my knowledge, the best study looking at potential explanations for the Red Sea crossing is the one by &lt;a href=&quot;http://dx.doi.org/10.1175/1520-0477(1992)073%3C0305:ATOEFT%3E2.0.CO;2&quot;&gt;Nof and Paldor (1992)&lt;/a&gt;. They present a couple of plausible scenarios for the crossing. The main one is the effect of strong winds blowing along the Gulf of Suez and they find that the sea level drop could be sufficient: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It is found that, even for moderate storms with wind speed of about 20 s&lt;sup&gt;−1&lt;/sup&gt; receding distance of more than 1 km and a sea level drop of more than 2.5 m are obtained. These relatively high values are a result of the unique geometry of the gulf (i.e., its rather small width-to-length and depth-to-length ratios) and the nonlinearity of the governing equation. Upon an abrupt relaxation of the wind, the water returns to its prewind position as a fast (nonlinear) gravity wave that floods the entire receding zone within minutes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The second mechanism involves a tsunami propagating along the Gulf of Suez from the Red Sea, but it seems like way more of a stretch.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nof D. and N. Paldor, 1992: Are There Oceanographic Explanations for the Israelites'Crossing of the Red Sea?. &lt;em&gt;Bull. Amer. Meteor. Soc.&lt;/em&gt;, 73, 305–314.&#xA;doi: &lt;a href=&quot;http://dx.doi.org/10.1175/1520-0477(1992)073%3C0305:ATOEFT%3E2.0.CO;2&quot;&gt;http://dx.doi.org/10.1175/1520-0477(1992)073%3C0305:ATOEFT%3E2.0.CO;2&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="725" LastEditDate="2014-12-14T06:01:12.910" LastActivityDate="2014-12-14T06:01:12.910" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2490" PostTypeId="1" AcceptedAnswerId="2603" CreationDate="2014-09-12T19:16:10.247" Score="30" ViewCount="5375" Body="&lt;p&gt;In the United States, the upcoming autumnal equinox is marked on most calendars as the &quot;first day of autumn.&quot; Similarly the solstices are commonly called the &quot;first day of summer&quot; and &quot;first day of winter.&quot; However in most other languages -- and even in older discussions in English -- the solstices have names like &quot;Midsummer's Day&quot; and &quot;Midwinter's Day.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there some sound reason (e.g. typical temperatures, asymmetrical sunrise/sunset times, thermal inertia, etc.) to consider a solstice as the first day of a new season, rather than the middle? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also (perhaps less on-topic) is there any record of when the change in nomenclature took place in the U.S.? Are there similar discrepancies in other English-speaking countries or in other cultures?&lt;/p&gt;&#xA;" OwnerUserId="887" OwnerDisplayName="rob" LastActivityDate="2023-11-11T14:32:37.723" Title="Equinoxes and solstices: start of the season or mid-season?" Tags="|terminology|meteorology|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2491" PostTypeId="1" CreationDate="2014-09-15T18:12:15.847" Score="13" ViewCount="2172" Body="&lt;p&gt;In a resistivity survey, how do we calculate the depth of penetration for a Schlumberger array?&lt;/p&gt;&#xA;" OwnerUserId="594" LastEditorUserId="44" LastEditDate="2014-09-17T13:01:04.387" LastActivityDate="2017-09-12T01:18:35.157" Title="How do you calculate the depth of penetration in a Schlumberger array?" Tags="|geophysics|measurements|in-situ-measurements|electromagnetism|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2493" PostTypeId="2" ParentId="2122" CreationDate="2014-09-16T07:40:07.680" Score="7" Body="&lt;p&gt;After I asked the question, the &lt;a href=&quot;http://www.esa.int/Our_Activities/Space_Science/Rosetta&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rosetta mission&lt;/a&gt; sent back some glorious images of rocks as jagged as those on any science fiction book cover:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/yC6tY.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suppose the difference is that these are on the surface of a comet, which, unlike the Moon, is geologically active. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are hardly what you'd call mountains - the whole nucleus is only 4km long, so the features shown must be hundreds of metres in size at best. But still, I would imagine freshly formed mountains would look something like this in the absence of erosion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It never rains but it pours. Here is a glorious photo of mountains on Pluto from NASA's New Horizons mission, from September 2015. Pluto is another (surprisingly) geologically active world, with apparently little erosion. These ones really are mountains, about three kilometres in height. They are probably made of water ice rather than rock, which is very hard at those temperatures. They also apprear very jagged.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HBSP3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HBSP3.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I conclude from this that mountains on active worlds without erosion will generally appear jagged; the smoothness of the Moon's mountains is not due to the absence of erosion - rather, they're smoothed &lt;em&gt;because&lt;/em&gt; of erosion, which in the Moon's case is primarily due to micrometeorites and takes place over a very long time. This is possible because the Moon is not geologically active, so its mountains are far older than the ones in the pictures above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, I can't resist editing again to add another image from the Rosetta mission, taking during the spacecraft's final descent before a controlled collision with the comet in September 2016. It's just an incredibly beautiful image. (&lt;a href=&quot;https://twitter.com/tedstryk/status/781702192772313092/photo/1?ref_src=twsrc%5Etfw&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aQq0I.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aQq0I.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="215" LastEditorUserId="215" LastEditDate="2016-09-30T13:43:07.520" LastActivityDate="2016-09-30T13:43:07.520" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2494" PostTypeId="2" ParentId="2490" CreationDate="2014-09-16T11:21:44.930" Score="8" Body="&lt;p&gt;This all depends on the context in which the word is used.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From an astronomical perspective, the solstices are midsummer and midwinter, and the equinoxes are the middle of autumn and the middle of spring.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the seasons, as perceived in terms of weather, lag somewhat behind the astronomical seasons (presumably this is due to the thermal mass of the planet?). For example, most people of my acquaintance think of northern-hemisphere summer as occupying approx. June/July/August, putting the June solstice near the start of it. Therefore, colloquially, the solstices and equinoxes seem to roughly match up with the starts of the seasons, and hence are often treated that way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why does this apply to the equinoxes more than the solstices? (citation needed - but  purely from personal observation, many people think of the summer solstice as &quot;midsummer&quot; but the spring equinox as &quot;the start of spring&quot;). I'm speculating, but my guess is that midsummer and midwinter are really obvious to anybody keeping an eye on the sky (when the sun reaches its greatest or least north/south extent, or &quot;when the days start getting shorter&quot;, or whatever). The equinoxes are slightly harder to judge, and so aren't noted in quite the same way.&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2014-09-17T11:58:14.077" LastActivityDate="2014-09-17T11:58:14.077" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2495" PostTypeId="2" ParentId="2400" CreationDate="2014-09-16T11:29:21.837" Score="3" Body="&lt;p&gt;It appears that, particularly for volcanos expelling andesitic magmas (those having a higher silica content, among other characteristics), the higher frequencies are more prevalent during the explosive portions of eruptions and tend to be absorbed by the more viscous magma during the tremors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the conclusion section of [1]:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The principal distinction between the basaltic and andesitic cases can be identified in the difference of the magma-gas flux between the basic state and the explosive events. In other words, the high viscosity of the andesitic magmas reduces the permanent degassing, thus producing a low-energy volcanic signal (volcanic tremor) and inhibiting higher vibration modes, whereas the explosions are induced by strong&#xA;  emission of magmatic fluids, whose ascent along the conduit&#xA;  produces Vulcanian-style eruptions and the excitation of several vibration modes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Some eruptions, e.g., the &lt;a href=&quot;http://en.wikipedia.org/wiki/Vulcanian_eruption#1930_eruption_of_Stromboli&quot; rel=&quot;nofollow&quot;&gt;1930 eruption of Stromboli&lt;/a&gt; are considered to be Vulcanian and would probably have slightly more energy in the higher frequency bands.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Reference:&lt;/p&gt;&#xA;  &#xA;  &lt;ol&gt;&#xA;  &lt;li&gt;De Lauro, E., De Martino, S., Falanga, M., Palo, M. (2011) Self-sustained vibrations in volcanic areas extracted by Independent Component Analysis: a review and new results. &lt;em&gt;Nonlin. Processes Geophys., 18&lt;/em&gt;, 925–940  &lt;a href=&quot;http://dx.doi.org/10.5194/npg-18-925-2011&quot; rel=&quot;nofollow&quot;&gt;[DOI]&lt;/a&gt; &lt;a href=&quot;http://www.nonlin-processes-geophys.net/18/925/2011/npg-18-925-2011.pdf&quot; rel=&quot;nofollow&quot;&gt;[PDF]&lt;/a&gt; (freely available)&lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="19" LastActivityDate="2014-09-16T11:29:21.837" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2496" PostTypeId="1" AcceptedAnswerId="2944" CreationDate="2014-09-16T13:44:55.997" Score="11" ViewCount="193" Body="&lt;p&gt;From &lt;a href=&quot;https://earthscience.stackexchange.com/a/2476&quot;&gt;this answer&lt;/a&gt;, I learned that rising magma may change oxidation state, which I wasn't aware of. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In [#1], the authors state in the abstract&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The conventional view holds that the oxidation state of a mantle-derived degassed magma reflects its source&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;From other research that has been conducted, the authors discussed that the &lt;a href=&quot;http://www.springerreference.com/docs/html/chapterdbid/326879.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;oxygen fugacity&lt;/a&gt; (the partial pressure of the &quot;non-ideal&quot; oxygen in the presence of the high pressures and temperatures, presumably of the magma itself) was controlled by a pair of redox reactions (their equations 11 and 12):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\ce{S_{(melt)}^2- + Fe2^3+O3_{(melt)} &amp;lt;=&amp;gt; SO2_{(gas)} + 6Fe^2+O_{(melt)} + O_{(melt)}^2-}$$&#xA;$$\ce{SO4_{(melt)}^2- + 2Fe^2+O_{(melt)} &amp;lt;=&amp;gt; SO2_{(gas)} + Fe2^3+O3_{(melt)} + O_{(melt)}^2-}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Their claim is that the change in the $\ce{Fe^3+}$ to $\ce{Fe^2+}$ ratio is due to the top reaction being favored during decompression (due to the equilibrium shift from the changes in pressure).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I get all of that so far, I think.  My question is a more fundamental one, being, if this equilibrium (#11) governing the changes in oxidation states becomes more prevalent as the pressure decreases rapidly, what are the governing equations for when the magma is deeper in the earth?  Do they favor the bottom equation (#12) instead, or are the reactions at that temperature and pressure completely different?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's possible I'm missing what the &quot;changing oxidation states&quot; aspect really means. A clarification of that would certainly be appreciated.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Reference:&lt;/p&gt;&#xA;  &#xA;  &lt;ol&gt;&#xA;  &lt;li&gt;Moussallam, Y., Oppenheimer, C., Scaillet, B., Gaillard, F., Kyle, P., Peters, N., &amp;amp; Donovan, A. (2014). Tracking the changing oxidation state of Erebus magmas, from mantle to surface, driven by magma ascent and degassing. &lt;em&gt;Earth and Planetary Science Letters, 393&lt;/em&gt;, 200-209. &lt;a href=&quot;http://dx.doi.org/10.1016/j.epsl.2014.02.055&quot; rel=&quot;nofollow noreferrer&quot;&gt;[DOI]&lt;/a&gt;&lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="19" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-12-03T18:40:31.943" Title="What is the mechanism behind changes in oxidation state (of iron, for example) as magma rises?" Tags="|volcanology|geochemistry|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2497" PostTypeId="1" AcceptedAnswerId="2529" CreationDate="2014-09-17T03:13:14.473" Score="19" ViewCount="297" Body="&lt;p&gt;I have not been able to find an estimate of how many known volcanoes host perennial ice masses, and it would be very useful to me. Does anyone know of any attempts to do this?&lt;/p&gt;&#xA;" OwnerUserId="63" LastEditorUserId="543" LastEditDate="2015-05-13T04:13:56.620" LastActivityDate="2015-05-13T04:13:56.620" Title="What percent of volcanoes are glaciated?" Tags="|volcanology|geography|glaciology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2498" PostTypeId="1" CreationDate="2014-09-17T06:36:34.430" Score="28" ViewCount="3233" Body="&lt;p&gt;The three main climate zones on Earth are tropics, temperate and polar. Due to Earth's axial tilt, the three zones experience different seasonal patterns:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_climate&quot;&gt;The tropics&lt;/a&gt; experience 2 or 4 wet/dry seasons depending on how the &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_rain_belt&quot;&gt;tropical rain belt&lt;/a&gt; passes over it.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Temperate_climate&quot;&gt;The temperate zones&lt;/a&gt; experience the 4 seasons.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Polar_climate&quot;&gt;The polar regions&lt;/a&gt; experience sun-less winters and an endless summer day, but due to the angle, receives little sunlight and is cold all-year round.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Of course it can get a lot more complex, but these are the broad types of climate seen on Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Suppose that Earth was extremely inclined, like Uranus - its axis lies parallel to its orbit. The equator would alternate between normal day/night to an endless twilight; the poles will alternate between endless twilight, endless noon, twilight, and endless midnight over the year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the same, very broad sense, what types of climate would this result in, and what would they be like?&lt;/p&gt;&#xA;" OwnerUserId="85" LastEditorUserId="87" LastEditDate="2014-11-19T15:14:03.883" LastActivityDate="2017-10-20T16:34:38.323" Title="What sort of climate zones would be present if Earth was tilted like Uranus?" Tags="|climate|planetary-science|hypothetical|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2499" PostTypeId="2" ParentId="2486" CreationDate="2014-09-17T15:16:57.960" Score="14" Body="&lt;p&gt;&lt;strong&gt;No, the atmosphere is not becoming thicker.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If anything at all, the atmosphere is getting thinner, but only on very long time scales.  Planet Earth very slowly loses parts of it atmosphere due to &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_escape&quot;&gt;atmospheric escape&lt;/a&gt;, either to space or to the solid Earth.  Historical atmospheric pressure is hard to determine, but billions of years ago, it might have been much thicker than it is now, in particular with a lot more greenhouse gases.  One clue is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Faint_young_Sun_paradox&quot;&gt;faint young sun paradox&lt;/a&gt;; we know there was liquid water at a time the solar output was 20% less, which would require so much greenhouse effect that the total atmospheric pressure must have been much higher.  But the jury is still out on that one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The atmosphere is not becoming significantly denser, either.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The concentration of gases that we are adding to the atmosphere is typically measured in &lt;em&gt;parts per million&lt;/em&gt; (ppm) or &lt;em&gt;parts per billion&lt;/em&gt; (ppb).  The effect of adding to this is small compared to the natural variability in atmospheric surface pressure / density due to weather and other effects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The atmosphere does not act like a lens.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2014-09-18T13:48:02.597" LastActivityDate="2014-09-18T13:48:02.597" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2500" PostTypeId="1" CreationDate="2014-09-17T18:57:54.533" Score="12" ViewCount="1426" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Casiquiare_canal&quot;&gt;Casiquiare canal&lt;/a&gt; is the world's largest bifurcation. Since such a large bifurcation seems unlikely to be produced and even less likely to stay for centuries, I wonder how old it is and why all the water didn't just stay in Orinoco.&lt;/p&gt;&#xA;" OwnerUserId="101" LastEditorUserId="124" LastEditDate="2014-09-18T06:20:15.763" LastActivityDate="2014-11-16T09:43:32.437" Title="How old is Casiquiare canal?" Tags="|earth-history|rivers|geography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2501" PostTypeId="1" CreationDate="2014-09-17T23:28:01.170" Score="12" ViewCount="1141" Body="&lt;p&gt;The &lt;a href=&quot;http://en.wikipedia.org/wiki/Siberian_Traps&quot;&gt;Siberian Traps&lt;/a&gt; are the modern day remnants of the flood basalt event.  Its eruptions is widely believed to be a major contributing factor of the Permo-Triassic extinction event.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In reading several sites on the matter, there seems to be two possible mechanisms (from the Wikipedia page linked above):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The source of the Siberian Traps basalt has variously been attributed to a mantle plume which impacted the base of the earth's crust and erupted through the Siberian Craton, or to processes related to plate tectonics. Another possible cause may be the impact that formed the Wilkes Land crater, which may have been contemporaneous and would have been nearly antipodal to the Traps.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The statement concludes with:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This controversial scientific debate is ongoing.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What evidence is there that would pinpoint which of these mechanisms (or any other) resulted in the Siberian Traps flood basalt eruptions?&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="56" LastEditDate="2014-09-18T04:04:12.850" LastActivityDate="2014-12-30T07:35:19.843" Title="What evidence is there for geological mechanisms that formed the Siberian traps flood basalt?" Tags="|volcanology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2502" PostTypeId="1" CreationDate="2014-09-18T03:35:27.707" Score="7" ViewCount="410" Body="&lt;p&gt;There are different types of &lt;a href=&quot;https://en.wikipedia.org/wiki/River_source&quot;&gt;river sources&lt;/a&gt;, most people might think of &lt;strong&gt;springs&lt;/strong&gt;, &lt;strong&gt;melting snow&lt;/strong&gt; or &lt;strong&gt;glaciers&lt;/strong&gt;, but other types of sources can include &lt;a href=&quot;https://en.wikipedia.org/wiki/La_Poudre_Pass&quot;&gt;&lt;strong&gt;wet meadows&lt;/strong&gt;&lt;/a&gt; or &lt;strong&gt;marshland&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of volume, what is the contribution of each type of source?&lt;/p&gt;&#xA;" OwnerUserId="85" LastActivityDate="2014-09-18T03:35:27.707" Title="What's the contribution of different types of river sources?" Tags="|hydrology|rivers|" AnswerCount="0" CommentCount="11" ClosedDate="2016-12-04T21:36:31.217" ContentLicense="CC BY-SA 3.0" />
  <row Id="2503" PostTypeId="1" CreationDate="2014-09-18T05:03:33.370" Score="16" ViewCount="5089" Body="&lt;p&gt;It is said that &lt;a href=&quot;http://www.energyquest.ca.gov/story/chapter08.html&quot;&gt;most of the fossil fuels&lt;/a&gt; in existence today (coal, oil, gas) came from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Carboniferous#Rocks_and_coal&quot;&gt;Carboniferous period&lt;/a&gt;. A unique set of circumstances lead to the creation of fossil fuels, which depends on anaerobic decomposition:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Plants evolved bark as an effective defense against insect herbivores&lt;/li&gt;&#xA;&lt;li&gt;Very few organisms at the time could digest or decompose the bark fiber &lt;a href=&quot;https://en.wikipedia.org/wiki/Lignin&quot;&gt;lignin&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Suppose that the Carboniferous period never happened, or for whatever reason the period never produced fossil fuels. How much fossil fuel would we have today instead? How much of today's fossil fuel deposits were created during the Carboniferous?&lt;/p&gt;&#xA;" OwnerUserId="85" LastEditorUserId="87" LastEditDate="2014-09-18T07:04:48.583" LastActivityDate="2014-09-18T14:07:06.687" Title="How much fossil fuel came from the Carboniferous?" Tags="|geology|fossil-fuel|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2504" PostTypeId="2" ParentId="954" CreationDate="2014-09-18T07:10:44.840" Score="6" Body="&lt;p&gt;Several articles suggest that the mechanisms involved with the weathering and/or the breakup of supercontinents as being a mechanism for this kind of glaciation, in the timeframe pertinent to your question, &lt;a href=&quot;http://en.wikipedia.org/wiki/Rodinia&quot;&gt;Rodinia&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the article &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S1674987112000898&quot;&gt;Precambrian supercontinents, glaciations, atmospheric oxygenation, metazoan evolution and an impact that may have changed the second half of Earth history&lt;/a&gt; (Young, 2013), a suggested mechanism of the onset of glaciation is the formation of the supercontinent, specifically, the author postulates:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Enhanced weathering on the orogenically and thermally buoyed supercontinents would have stripped $CO_2$ from the atmosphere, initiating a cooling trend that resulted in continental glaciation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The Polarisbreen Formation is touted in the article &lt;a href=&quot;https://www.princeton.edu/geosciences/people/maloof/pdf/marinoan.pdf&quot;&gt;The Marinoan glaciation (Neoproterozoic) in&#xA;northeast Svalbard&lt;/a&gt; (Halverson et al. 2004) suggests that weathering as being one of the main factors for the sustained glaciation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An alternative hypothesis is proposed in the article &lt;a href=&quot;https://www.utdallas.edu/~rjstern/pdfs/VW2SE08.pdf&quot;&gt;From Volcanic Winter to Snowball Earth: An Alternative Explanation for Neoproterozoic Biosphere Stress&lt;/a&gt; (Stern et al. 2008), where the authors suggest that increased global volcanism from the breakup of the supercontinent.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-09-18T07:10:44.840" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2505" PostTypeId="2" ParentId="2503" CreationDate="2014-09-18T13:47:37.047" Score="8" Body="&lt;p&gt;The process you're describing in the question is the one at the origin of coal. Although coal deposits are known from the Devonian to the Quaternary, they have been 3 major periods of depositions (see &lt;strong&gt;Thomas 2013&lt;/strong&gt;): the Carboniferous-Early Permian, the Jurassic-Cretaceous and during the Cenozoic. So, indeed the Carboniferous is one of the main period of coal deposit but I couldn't find any numerical evidence in the literature that this is the &quot;main&quot; period of deposit. The idea that it is is most likely due to the fact that the western Europe and eastern USA coal mines (hence historically the most noteworthy) all happen to be Carboniferous.&lt;br&gt;&#xA;But as far as oil (petroleum) is concerned, according to &lt;strong&gt;Klemme &amp;amp; Ulmishek 1991&lt;/strong&gt; (straight from the abstract):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Six stratigraphic intervals, representing one-third of Phanerozoic&#xA;  time, contain petroleum source rocks that have provided more than 90%&#xA;  of the world's discovered original reserves of oil and gas (in barrels&#xA;  of oil equivalent). The six intervals are (1) Silurian (generated 9%&#xA;  of the world's reserves), (2) Upper Devonian-Tournaisian (8% of&#xA;  reserves), (3) Pennsylvanian-Lower Permian (8% of reserves), (4) Upper&#xA;  Jurassic (25% of reserves), (5) middle Cretaceous (29% of reserves),&#xA;  and (6) Oligocene-Miocene (12.5% of reserves)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;See &lt;strong&gt;Klemme 1994&lt;/strong&gt; for a detailed explanation on the origins of the Jurassic source rocks (i. e. 25% of the world's reserve at the time): most of them are marine, but some are fluvial or from lagoonal inland seas (table 3.2).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;References:&lt;br&gt;&#xA;Klemme, 1994. Petroleum systems of the world involving Upper Jurassic source rocks. In Maggon &amp;amp; Dow (Eds), &lt;em&gt;The petroleum system - from source to trap&lt;/em&gt;, AAPG Memoir, 60: 51-72.&lt;br&gt;&#xA;Klemme &amp;amp; Ulmishek, 1991. Effective petroleum source rocks of the world; stratigraphic distribution and controlling depositional factors&#xA;&lt;em&gt;AAPG Bulletin&lt;/em&gt;, 75: 1809-1851.&lt;br&gt;&#xA;Thomas, 2013. &lt;em&gt;Coal Geology, 2nd Edition.&lt;/em&gt; Wiley-Blackwell, 444pp.&#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-09-18T14:07:06.687" LastActivityDate="2014-09-18T14:07:06.687" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2506" PostTypeId="2" ParentId="342" CreationDate="2014-09-19T01:38:17.567" Score="9" Body="&lt;p&gt;I'm gonna hazard a guess here: &lt;strong&gt;They can't&lt;/strong&gt;. While I don't have any evidence for this claim, it seems likely that there are too many small-scale non-linear processes feeding in to the overall generation process to ever be able to sensibly derive any kind of analytical solution based on physical first-principles. I &lt;em&gt;think&lt;/em&gt; that's what you're asking.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, basically, these equations are an empirical model. The parameters don't have any relation to the physical processes that generated the meanders - they are just descriptions of the resultant shape. The generation process for a model like this is something along the lines of:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Inspect the data qualitatively&lt;/li&gt;&#xA;&lt;li&gt;Come up with some potential models that could approximate what you're seeing. In this instance, sinusoidal and sequentially linked circles look like they might work.&lt;/li&gt;&#xA;&lt;li&gt;For each model, apply and verify:&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Attempt to fit the model to some of the data.&lt;/li&gt;&#xA;&lt;li&gt;Apply the model to some of the rest of the data, and check it's performance (also, pay attention to parsimony).&lt;/li&gt;&#xA;&lt;/ol&gt;&lt;/li&gt;&#xA;&lt;li&gt;Choose the model with the best performance as your model.&lt;/li&gt;&#xA;&lt;li&gt;With your model, perform some analysis of the model fit (residual analysis, etc). If it looks like there are patterns in the residuals that could be reasonably modelled, go back to 2. and come up with some model variants.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;As far as I can tell from the referenced paper, this is roughly the process that the authors used. The values of each of the parameters are basically empirically obtained, to allow the model to best fit the majority of the data.&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2014-09-19T01:38:17.567" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2507" PostTypeId="1" AcceptedAnswerId="2682" CreationDate="2014-09-19T17:11:25.683" Score="15" ViewCount="348" Body="&lt;p&gt;I'm in an AP Environmental Science course, and while reading part of the chapter in my textbook about the nitrogen cycle, I saw this picture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/aahcm.png&quot; alt=&quot;nitrogen human input&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I was wondering is what caused that dip in the nitrogen input in about 1995? I've researched online, but I haven't found anything.&lt;/p&gt;&#xA;" OwnerUserId="891" LastEditorUserId="2958" LastEditDate="2018-12-29T20:12:16.920" LastActivityDate="2018-12-29T20:12:16.920" Title="Break in human nitrogen input in 1990s" Tags="|statistics|human-influence|nitrogen|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="2509" PostTypeId="1" CreationDate="2014-09-21T01:43:53.610" Score="13" ViewCount="5258" Body="&lt;p&gt;According to the Australian Geological Survey Organisation paper &lt;a href=&quot;http://www.ga.gov.au/image_cache/GA5392.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kimberlite and lamproite diamond pipes&lt;/a&gt; (Jaques, 1998), economic deposits of volcanically-formed diamonds are&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;restricted to ancient cratons (typically &gt;2.Ga) or cratonised provinces older than 1.8 Ga&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Ga = billion years&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and that rarely do younger accreted cratonised belts contain economic deposits.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This relationship can be seen in the &lt;a href=&quot;http://www.geus.dk/minex/minex-22-uk.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Greenland Mineral Exploration Newsletter&lt;/a&gt; map below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/tvPOh.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is it about the ancient craton geology (and geochemistry) that results in the associated kimberlite pipes containing economically important diamond deposits? &lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="725" LastEditorDisplayName="user889" LastEditDate="2016-05-10T09:39:17.997" LastActivityDate="2016-05-10T09:39:17.997" Title="What is it about ancient craton geology that results in associated kimberlite pipes containing economic diamond deposits?" Tags="|geochemistry|volcanology|economic-geology|kimberlite|diamond|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2510" PostTypeId="2" ParentId="1007" CreationDate="2014-09-21T02:45:13.670" Score="7" Body="&lt;p&gt;According to the paper &lt;a href=&quot;http://people.oregonstate.edu/~carlsand/carlson_encyclopedia_Quat_2013_YD.pdf&quot; rel=&quot;nofollow&quot;&gt;The Younger Dryas Climate Event&lt;/a&gt; (Carlson, 2013), the Younger Dryas was a period of &lt;em&gt;warming&lt;/em&gt; in the extratropical Southern Hemisphere, and quite a significant one as well, as, from the article:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;SST records show a warming&#xA;  of 0.3–1.9 C from the southeast Atlantic to New Zealand&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is supported by&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Speleothem and pollen records from New Zealand and&#xA;  pollen records from South America confirm that the Younger&#xA;  Dryas was generally a period of warming&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Citing glacial retreat measured in places such as New Zealand, the article &lt;a href=&quot;http://www.nature.com/nature/journal/v467/n7312/full/nature09313.html&quot; rel=&quot;nofollow&quot;&gt;Glacier retreat in New Zealand during the Younger Dryas stadial&lt;/a&gt; (Kaplan et al. 2010) hypothesised the mechanism to be due to&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;extensive winter sea ice and curtailed meridional ocean overturning in the North Atlantic led to a strong interhemispheric thermal gradient8 during late-glacial times, in turn leading to increased upwelling and $\mathrm{CO}_2$ release from the Southern Ocean, thereby triggering Southern Hemisphere warming during the northern Younger Dryas.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Research on the deposits observed in the Australian tropics of the age in the article &lt;a href=&quot;http://people.rses.anu.edu.au/dedeckker_p/pubs/20.pdf&quot; rel=&quot;nofollow&quot;&gt;Late Pleistocene record of cyclic eolian activity from tropical Australia suggesting the Younger Dryas is not an unusual climatic event&lt;/a&gt; (De Deckker et al. 1991) revealed that the southern tropics experienced a drying phase, that fits well with a cyclic climatic phase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of the southern tropics, the article &lt;a href=&quot;http://horizon.documentation.ird.fr/exl-doc/pleins_textes/pleins_textes_7/divers2/010028119.pdf&quot; rel=&quot;nofollow&quot;&gt;Tropical climates in the game of two hemispheres revealed by&#xA;abrupt climatic change&lt;/a&gt; (Ledru et al. 2002) suggest that there were significant variations, as recorded in pollen samples from the South American tropics, leading the authors to suggest that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;One consequence of the Younger Dryas changes would be the location of the Intratropical Convergence Zone in a southern position, so that even tropical regions would have been under Arctic influence.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="725" LastEditDate="2014-12-03T04:43:46.173" LastActivityDate="2014-12-03T04:43:46.173" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2511" PostTypeId="1" AcceptedAnswerId="2512" CreationDate="2014-09-21T21:41:45.033" Score="22" ViewCount="23126" Body="&lt;p&gt;Where is obsidian found?&#xA;Is it typically found on the surface or underground? &#xA;If underground, how far under (meters or feet would be perfect)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, is it found everywhere on Earth, or just in areas where volcanic activity is (or was recently) high?&lt;/p&gt;&#xA;" OwnerUserId="898" LastEditorDisplayName="user20559" LastEditDate="2021-05-11T09:44:52.157" LastActivityDate="2021-05-11T09:44:52.157" Title="Where can obsidian be found?" Tags="|geology|volcanology|mineralogy|minerals|" AnswerCount="3" CommentCount="4" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2512" PostTypeId="2" ParentId="2511" CreationDate="2014-09-21T21:51:07.477" Score="18" Body="&lt;p&gt;Obsidian is formed when a rhyolitic (or felsic) lava flows cool rapidly. This must mean that it's mostly available  on the surface (and I think if you go near volcanos you can find pieces of Obsidian on the ground) because molten rock cools much faster above ground than it does below, allowing the melt to cool with small crystals (as opposed to intrusive rocks which have larger crystals). This means that Obsidian is an extrusive igneous rock.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am betting that Obsidian is very common around most active volcanos around the world!&lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-09-21T21:51:07.477" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2513" PostTypeId="2" ParentId="2511" CreationDate="2014-09-21T23:14:19.003" Score="28" Body="&lt;p&gt;The processes forming obsidian are not well understood because an active obsidian-forming eruption has never been recorded by humans. However, we can make many inferences from the composition of the rock and settings in which it is found.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obsidian is more than 70% weight percent SiO&lt;sub&gt;2&lt;/sub&gt; (i.e. rhyolitic), but has less than 0.5 weight percent H&lt;sub&gt;2&lt;/sub&gt;O, and almost 0% gas bubbles (vescicles). This is very unusual because high-silica magma typically also contains a high volatile content. That means they can contain up to 8% H&lt;sub&gt;2&lt;/sub&gt;O, CO&lt;sub&gt;2&lt;/sub&gt; and other species that easily become gasses. Because the rock is &quot;missing&quot; water and has no gas bubbles, we know that the gas escaped the rock while it was molten. This process normally takes quite a bit of time, so you might think obsidian cools slowly so that all the volatiles could diffuse out of the rock without forming bubbles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you thought that, you would be wrong.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's why: The SiO&lt;sub&gt;2&lt;/sub&gt; is almost 100% in glass form (amorphous) rather than in crystals. Any crystals that do exist are microscopic. This is strong evidence saying the rock cooled quickly, because if it cooled slowly the SiO&lt;sub&gt;2&lt;/sub&gt; would have had time to organize itself into crystals as it cooled. Further supporting the idea that it cools quickly is the fact that it is not observed underground (as an intrusive rock, which would have cooled slowly.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One way to explain this &quot;low volatile, glassy texture&quot; paradox is to say the lava was kept hot for long enough time that the gasses were able to escape, and then cooled very suddenly. Another possibility is that the parental magma was extremely dry (low-volatile) to begin with for some reason.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Modern humans have never seen obsidian erupt primarily because rhyolitic eruptions are rare. However, obsidian is rare even among rhyolitic eruptions, presumably because lots of open-system degassing followed by rapid cooling is an unusual phenomenon. There are many places in the world that seem to habitually produce obsidian and have produced enormous volumes of it. The Valles Caldera in New Mexico is a particularly good example, with a huge lava flow and several lava domes all constructed from obsidian. Similar lava domes called the Inyo Domes near Mono Lake, CA have been fundamental to the understanding of the behavior of stable isotopes in magmatic systems and are probably the most well-known outcrops of obsidian among geologists.&lt;/p&gt;&#xA;" OwnerUserId="63" LastEditorUserId="725" LastEditDate="2014-12-14T06:18:59.173" LastActivityDate="2014-12-14T06:18:59.173" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2514" PostTypeId="2" ParentId="2511" CreationDate="2014-09-22T09:02:28.153" Score="12" Body="&lt;p&gt;I have seen it on the surface in some the lava fields of Iceland. This is consistent with @Neo answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obsidian is not that often present, but if present, there is usually plenty around. It occurs in rather large pieces. This photo is from Landmannalaugar.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/B28ia.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="841" LastEditorUserId="841" LastEditDate="2014-09-22T17:18:42.383" LastActivityDate="2014-09-22T17:18:42.383" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2515" PostTypeId="1" CreationDate="2014-09-22T16:37:54.160" Score="6" ViewCount="3053" Body="&lt;p&gt;How is mm of Hg per degree Celsius converted to kPa per degree Celsius? I also need  the equation for computing the value of A (slope) in mm of Hg per degree Celsius.&lt;/p&gt;&#xA;" OwnerUserId="903" LastEditorUserId="64" LastEditDate="2014-09-22T19:39:54.050" LastActivityDate="2016-07-05T02:41:58.337" Title="Slope of Saturation vapor pressure versus temperature-A parameter in Penman's equation" Tags="|hydrology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2516" PostTypeId="2" ParentId="2515" CreationDate="2014-09-22T19:38:04.837" Score="9" Body="&lt;p&gt;You can convert mm Hg to kPa with the conversion factor $0.133322368\ \mathrm{kPa\ mmHg^{-1}}$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Saturation vapor pressure as a function of temperature is &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ e_s(T) = e_{s0}\exp\left[\left(\dfrac{L_v(T)}{R_v}\right)\left(\dfrac{1}{T_0} -\dfrac{1}{T} \right)\right], $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $L_v(T)$ is the specific enthalpy of vaporization, $R_v$ is the specific gas constant for water vapor, $T_0$ is reference temperature (273.15 K) and $e_{s0}$ is the saturation vapor pressure at $T_0$ (611 Pa).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can find the slope of this curve by taking the derivative $\dfrac{d e_s}{dT}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that the units of $e_s$ and $T$ are Pa and K respectively in the equation above.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2014-09-23T03:17:06.390" LastActivityDate="2014-09-23T03:17:06.390" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2517" PostTypeId="2" ParentId="2515" CreationDate="2014-09-23T11:47:33.423" Score="1" Body="&lt;p&gt;finally i could find out that both units are not compatible to convert. Little bit speculated about the fact.&lt;br&gt;&#xA;The equation for finding the slope in mmHg/&amp;deg;C =                             4098*(4.584*exp(17.27*T/237.3+T))/(T+237.3)^2. &lt;/p&gt;&#xA;" OwnerUserId="903" LastEditorUserId="111" LastEditDate="2016-07-05T02:41:58.337" LastActivityDate="2016-07-05T02:41:58.337" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2519" PostTypeId="1" AcceptedAnswerId="2520" CreationDate="2014-09-24T06:19:07.053" Score="26" ViewCount="37095" Body="&lt;p&gt;I recently visited Slovenia where I saw several rivers with a strong blue-green color.&#xA;Here is an example from one of the tributaries of the Soča river near Kobarid. The locals refer to it as an &quot;emerald&quot; color.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/BvMLw.jpg&quot; alt=&quot;Emerald blue-green river in Soča valley&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Notice how the color gets more intense at the deeper waters. What causes this color? A web search shows that the two most cited reasons are blue-green algae and &quot;limestone particles&quot;. I'm guessing that the more plausible explanation in this case is the limestone one, because this area is dominated by limestone. But, is it really &quot;particles&quot;? I would think that the calcium carbonate would dissolve in the water, instead of being suspended as solids.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-03-04T22:10:09.007" Title="Why are alpine river water green - blue?" Tags="|rivers|limestone|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2520" PostTypeId="2" ParentId="2519" CreationDate="2014-09-24T08:40:58.887" Score="16" Body="&lt;p&gt;According to the website &lt;a href=&quot;http://www.mountainnature.com/geology/MountainLakes.htm&quot;&gt;Putting the Emerald in Emerald Lake – Where do the colours come from?&lt;/a&gt;, the reason for the colour is the same that occurs in lakes, it is due to what is known as or similar material to '&lt;a href=&quot;http://en.wikipedia.org/wiki/Rock_flour&quot;&gt;rock flour&lt;/a&gt;' - consisting of&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;of fine-grained, silt-sized particles of rock, generated by mechanical grinding of bedrock&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and relevant to a river environment&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;When the sediments enter a river, they turn the river's colour grey, light brown, iridescent blue-green, or milky white.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The colour is due to:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the suspended material distorts the wavelengths of light, reflecting back more of the green and blue end of the spectrum &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;These usually originate from glacial melt, even though there are no glaciers in the Julian Alps presently, but there used to be, resulting in according to the &lt;a href=&quot;http://www.gepgis.eu/en/wpo6/&quot;&gt;WP6 Hydro-geological upgrade and improvement of the GIS of the sources of drinking water&lt;/a&gt; webpage as having&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The intergranular aquifer in the alluvium of the Soča/Isonzo River, which is composed of fluvial and fluvioglacial gravel and sand sediments with individual lenses of conglomerates&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;further explained in the article &lt;a href=&quot;http://www.risknat.org/projets/sismovalp/CD3/e-Synthese%20Vallees/8-EARS_SocaValley.pdf&quot;&gt;Bovec basin (Upper Soča valley, Slovenia)&lt;/a&gt;, as having&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Quaternary &#xA;  sediments are represented from bottom to top by partly lithified glaciofluvial sediments, overlain by lacustrine &#xA;  chalk. During the Holocene, the chalk was partly eroded (in some areas totally) and covered by glaciofluvial &#xA;  sand and gravel which are weakly cemented in some parts into conglomerate and by unconsolidated moraine &#xA;  (till).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Potentially, plenty of source material. The particles are small enough to be suspended in the water of the Soča River. &lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-09-24T08:40:58.887" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2521" PostTypeId="1" CreationDate="2014-09-24T09:59:38.490" Score="24" ViewCount="34039" Body="&lt;p&gt;I'm doing some homework on the increase of $\mathrm{CO}_2$ in the atmosphere. On one of the graphs it shows the amount of $\mathrm{CO}_2$ peaks in May and has a low in November. Why is this? Shouldn't it just be constantly going up?&lt;/p&gt;&#xA;" OwnerUserId="909" LastEditorDisplayName="user889" LastEditDate="2015-03-28T10:26:10.060" LastActivityDate="2017-04-21T16:04:26.973" Title="Why is there a seasonal cycle to the amount of CO2 in the atmosphere?" Tags="|atmosphere|climate-change|co2|homework|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2522" PostTypeId="2" ParentId="2521" CreationDate="2014-09-24T11:15:47.457" Score="21" Body="&lt;p&gt;Overall, the measured amount of $\mathrm{CO}_2$ increases, but in a cyclic pattern, as can be seen in observations shown below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/esNBH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image source: &lt;a href=&quot;http://www.esrl.noaa.gov/gmd/ccgg/trends/&quot; rel=&quot;noreferrer&quot;&gt;NOAA: Trends in Atmospheric Carbon Dioxide&lt;/a&gt; (numerous observation data sets and graphs are available from that website)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fluctuations are seasonal, which is explained in the web page &lt;a href=&quot;http://www.sciencedaily.com/releases/2013/08/130812170338.htm&quot; rel=&quot;noreferrer&quot;&gt;Seasonal carbon dioxide range expanding as more is added to Earth's atmosphere&lt;/a&gt; (NSF, 2013) summarises the seasonality as being&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Levels of carbon dioxide in the atmosphere rise and fall each year as&#xA;  plants, through photosynthesis and respiration, take up the gas in&#xA;  spring and summer, and release it in fall and winter. Now the range of&#xA;  that cycle is expanding as more carbon dioxide is emitted from burning&#xA;  fossil fuels and other human activities.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Specifically, the effect is more pronounced in the northern hemisphere, with&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;more carbon is accumulating in forests and other vegetation and soils in the Northern Hemisphere during the summer, and more carbon is being released in the fall and winter&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Daily as well as seasonal variations were observed in northern Japan, reported in the article &lt;a href=&quot;http://svr4.terrapub.co.jp/journals/GJ/pdf/4106/41060429.pdf&quot; rel=&quot;noreferrer&quot;&gt;Diurnal and seasonal variations in atmospheric $\mathrm{CO}_2$ in Sapporo, Japan:&#xA;Anthropogenic sources and biogenic sinks&lt;/a&gt; (Miyaoka et al. 2007).&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="725" LastEditDate="2014-12-14T06:23:38.533" LastActivityDate="2014-12-14T06:23:38.533" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2523" PostTypeId="1" AcceptedAnswerId="2524" CreationDate="2014-09-21T21:09:36.610" Score="18" ViewCount="53275" Body="&lt;p&gt;How much longer does Earth have until the core turns solid?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does global warming change these estimates at all?&lt;/p&gt;&#xA;" OwnerDisplayName="Scottie" LastEditorDisplayName="user12525" LastEditDate="2019-04-27T09:35:25.677" LastActivityDate="2019-04-27T09:35:25.677" Title="How long until Earth's core solidifies?" Tags="|geology|geophysics|core|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2524" PostTypeId="2" ParentId="2523" CreationDate="2014-09-22T05:44:43.770" Score="21" Body="&lt;p&gt;Global warming has to do with the surface only, and at best involves changes of 20 degrees at the outside extreme, in comparison to the earth's core, which is as hot as the surface of the sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For complete accuracy, and to reflect what a commenter has pointed out, the inner core is solid already, but this is because of the extremely high pressure of the overlying layers of the outer core (which IS liquid), and the mantle. See the Wikipedia articles concerning the &lt;a href=&quot;https://en.wikipedia.org/wiki/Inner_core&quot;&gt;Inner Core&lt;/a&gt;, and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Outer_core&quot;&gt;Outer Core&lt;/a&gt;.  Note that it is the outer core which creates the earth's magnetic field.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer is that the earth's core will &lt;strong&gt;never&lt;/strong&gt; be solid.  And I do mean NEVER.  Now, that being said, there is only one way it could ever happen and that is if the earth happened to get thrown out of its orbit to become a &lt;a href=&quot;https://en.wikipedia.org/wiki/Rogue_planet&quot;&gt;nomad planet&lt;/a&gt;.  Then it might have time for its core to cool.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason I say this is because it will take longer for the earth's core to turn solid than it will take for the sun to run out of nuclear fuel and expand to engulf the earth.  At that point, the earth will be vaporized as it spirals out of its orbit into the sun.  The core would soon turn into incandescent gas.  This will occur something like 4 to 5 billion years from now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If by some chance the earth were to become a nomad planet, free to cool in its own good time, then it would take a long long time.  See &lt;em&gt;Energetics of the Earth&lt;/em&gt; by John Verhoogen, available online via &lt;a href=&quot;http://books.google.fr/books?id=yTsrAAAAYAAJ&amp;amp;pg=PA97&amp;amp;lpg=PA97&amp;amp;dq=EARTH%20CORE%20COOLING&amp;amp;source=bl&amp;amp;ots=j-E8y1tiXe&amp;amp;sig=QFhNnqFbvPPocI1dTeFvSjcg_0w&amp;amp;hl=fr&amp;amp;ei=Upf0SbqyCaPNjAe8hvXXDA&amp;amp;sa=X&amp;amp;oi=book_result&amp;amp;ct=result&amp;amp;resnum=32#v=onepage&amp;amp;q=EARTH%20CORE%20COOLING&amp;amp;f=false&quot;&gt;Google Books&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main factor slowing down the cooling is radioactive decay of long living atoms, namely Uranium-238, Uranium-235, Thorium-232, and Potassium-40, with half-lives of roughly 4.47 billion years, 704 million years, 14.1 billion years, and 1.28 billion years, respectively. From the half-lives of these isotopes and a comparison with the age of Earth, you can see that internal heat production via radioactive decay will likely persist at near current levels for quite some time to come. Verhoogen gives 5000 K as the core temperature now, and a 250 K cooling since the formation of the Solar System, 4.5 billion years ago.  If it really does cool at that rate (55 degrees per billion years), it would take something like 91 billion years to cool to 0 Kelvin.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But don't worry, it won't happen, as I said.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Edited to add detail&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="915" OwnerDisplayName="Cyberherbalist" LastEditorUserId="915" LastEditDate="2014-09-25T15:27:33.720" LastActivityDate="2014-09-25T15:27:33.720" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="2526" PostTypeId="1" AcceptedAnswerId="2582" CreationDate="2014-09-24T20:14:33.970" Score="11" ViewCount="2692" Body="&lt;p&gt;I know compressibility is related to the pressure and temperature of the water parcel, but what is the physical/molecular reason as to why colder water is more compressible?&lt;/p&gt;&#xA;" OwnerUserId="850" LastEditorDisplayName="user889" LastEditDate="2014-12-24T03:45:32.247" LastActivityDate="2014-12-24T03:45:32.247" Title="Why is colder seawater more compressible?" Tags="|ocean|oceanography|temperature|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2528" PostTypeId="1" CreationDate="2014-09-25T00:02:06.367" Score="9" ViewCount="9616" Body="&lt;p&gt;It is said of amber that it requires thousands of years of time and much pressure to produce amber from tree resin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This was also said of diamond as well, but we now produce artificial diamonds by the ton.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the question is, could we not make artificial amber, or is this somehow not possible?&lt;/p&gt;&#xA;" OwnerUserId="915" LastActivityDate="2021-06-02T19:40:57.430" Title="Is it theoretically possible to artificially create amber?" Tags="|mineralogy|amber|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2529" PostTypeId="2" ParentId="2497" CreationDate="2014-09-25T05:21:15.277" Score="19" Body="&lt;p&gt;21.7%, by my calculations (338 / 1556 holocene-active volcanoes). I calculated perennial snow by combining 6 weeks of MOD10A2 data from winter and summer weeks in 2014 to figure out which pixels had snow both in the summer and the winter. My source code for that is available &lt;a href=&quot;https://gist.github.com/foobarbecue/32fe9d9d727d48b039e2&quot; rel=&quot;noreferrer&quot;&gt;as a gist&lt;/a&gt; (an older version accidentally classified cloud as snow; that's been fixed). Then I checked if these pixels fell within 10km of the volcanoes in the Smithsonian Institution's Global Volcanism Database. I also plotted the woefully incomplete Global Land Ice Measurements from Space glacier polygons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are clearly a few false-positives on ocean islands... I think this is due to MOD10A2 marking choppy surf as snow. Looking into that. I intend to publish this and will put a reference here if it is published.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's what the map looks like for part of Alaska:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/gTNkM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And the whole world:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/e2jjg.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="63" LastEditorUserId="63" LastEditDate="2015-05-12T00:15:50.417" LastActivityDate="2015-05-12T00:15:50.417" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2530" PostTypeId="1" AcceptedAnswerId="4266" CreationDate="2014-09-25T05:35:30.900" Score="16" ViewCount="2070" Body="&lt;p&gt;In reading the question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2267/what-would-the-geology-and-climate-of-a-supposed-landmass-near-the-pole-be-like&quot;&gt;What would the geology and climate of a supposed landmass near the pole be like, assuming a thoroughly warmer planet?&lt;/a&gt;, it came to mind that another factor may cause a shift in the long term climatic patterns should the Greenland Ice sheet continue melt - the effects of a 'taller' Greenland, due to its isostatic rebound.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the &lt;a href=&quot;http://polarfield.com/blog/tag/isostatic-rebound/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Polar Field Services website&lt;/a&gt;, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The enormous weight of the ice down-warped the land surface, causing the material underlying these land masses to slowly flow away. The physics are similar to the reasons a balloon deforms when you press down on it. In the same way that the balloon reshapes itself when you remove your hand, the land actually pops back up over several thousand years when the weight of expansive ice sheets no longer weighs down the underlying area. &lt;strong&gt;In Greenland, where the ice sheet is currently receding, the island is actively rebounding.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Given that there are already peaks of up to about &lt;a href=&quot;http://en.wikipedia.org/wiki/Gunnbj%C3%B8rn_Fjeld&quot; rel=&quot;nofollow noreferrer&quot;&gt;3.7km in altitude&lt;/a&gt;, my related questions are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;How high would these peaks go?&lt;/li&gt;&#xA;&lt;li&gt;What effect would a 'taller' Greenland have on climatic patterns?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-01-15T12:48:03.913" Title="How much would the Greenland landmass isostatic rebound contribute to long term climate change?" Tags="|climate|climate-change|climate-models|greenland|isostasy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2532" PostTypeId="2" ParentId="2424" CreationDate="2014-09-25T17:04:40.430" Score="8" Body="&lt;p&gt;In his book, Simpson (Simpson, J. E. (1994). Sea breeze and local winds. Cambridge University Press) shows a figure that includes the pressure difference between Jersey in the Channel Islands and Paris. It gives an idea of the magnitude of the pressure difference. As was mentioned in the comments, sea breeze tends to be perceived as a density current on constant pressure surfaces. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/lZIHv.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-09-25T17:04:40.430" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2533" PostTypeId="1" AcceptedAnswerId="2536" CreationDate="2014-09-25T23:31:19.380" Score="10" ViewCount="1849" Body="&lt;p&gt;I need to find the per capita $\ce{CO2}$ emissions for Canada in 2010 (expressed in kg/day). I know that Canada had $\ce{CO2}$ emissions of 0.55 (Gt) and a population of 34 million in 2010.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am just having trouble on how to calculate it per capita emissions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried dividing 0.55 by 34,000,000 (I looked up my question and saw someone suggest this) but having an answer of $1.6\times10^{-8}$ doesn't really seem correct to me.&lt;/p&gt;&#xA;" OwnerUserId="920" LastEditorUserId="543" LastEditDate="2017-04-26T06:11:42.847" LastActivityDate="2020-09-25T05:47:33.333" Title="How do I calculate Per capita $\ce{CO2}$ emissions?" Tags="|atmosphere|climate-change|carbon|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2535" PostTypeId="1" CreationDate="2014-09-26T04:38:27.487" Score="3" ViewCount="178" Body="&lt;p&gt;For many years there are terrible forest fires in the U.S. (for example); I was wondering about pro-active measures ( I'm sure there are many). One possibility is using a small army of robots that are designed to 'go anywhere' and act like 'artificial goats' eating any dry brush or grass. Of course another army of robots could ,using local water from a lake or streams, fill up with say 100 gallons each ( if designed for this) and spray water everywhere even without a fire emergency.  This might sound silly but you have a lot of robotic derigibles carrying 1000 gallons of water or more slowly floating over a forest sprinkling water everywhere like a mild shower. So could certain 'robot armies' be used to fight the dry conditions in a forest?&lt;/p&gt;&#xA;" OwnerUserId="855" LastEditorUserId="855" LastEditDate="2014-09-28T04:19:34.777" LastActivityDate="2020-09-25T04:21:57.387" Title="Regarding forest fire season and using robotic devices for proactive efforts before any fires" Tags="|human-influence|forest|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2536" PostTypeId="2" ParentId="2533" CreationDate="2014-09-26T09:38:39.383" Score="6" Body="&lt;p&gt;You have the right idea, but you have your units and orders of magnitude confused.&#xA;You have started with knowing that Canada has 34 million people, and emits 0.55Gt - i.e. $0.55 \times 10^9$ tonnes - per year. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now rather than just using those figures, think about the units that you have, and the units that you've been asked to give the answer in. How many kilograms are in a gigatonne? Once you have a figure for kilograms per year, how will you convert this to kilograms per day?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NB I haven't checked your actual figures - only your arithmetic!&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2014-09-26T09:38:39.383" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2537" PostTypeId="2" ParentId="2535" CreationDate="2014-09-26T14:50:17.980" Score="3" Body="&lt;p&gt;It has been suggested that proper management of large herds of goats, cattle, deer, or elephants on the land are effective in preventing desertification. So perhaps this could be used to mitigate conditions leading to excessive grass and forest fires. Maybe your idea would scale-up more effectively if the robots were set to manage large herds of animals that themselves do what herbivores do to control fuel, fertilize, and cultivate forest and grassland.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So perhaps 'robot goatherds' rather than 'robot goats' is what you need.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I really don't know if this would be a good idea or not but you may find this &lt;a href=&quot;https://www.ted.com/talks/allan_savory_how_to_green_the_world_s_deserts_and_reverse_climate_change&quot; rel=&quot;nofollow&quot;&gt;TED talk&lt;/a&gt; about using stock animals to combat desertification very interesting.&lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-09-26T14:50:17.980" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2538" PostTypeId="1" CreationDate="2014-09-26T15:24:29.933" Score="14" ViewCount="104" Body="&lt;p&gt;In the GOES-13 Visible channel, there seems to be a morning/afternoon asymmetry in the data. I'm wondering what might cause this. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this example data, the morning is the lower branch, and the afternoon is the upper branch. The y-axis is the pixel level (0..255), the x-axis is the Sun's local altitude above the horizon. The location is the Gulf of St. Lawrence, on the east coast of Canada. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Latitude +46.94N, longitude -63.21W (not far from the center of the images below.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/0LhDf.png&quot; alt=&quot;GOES Visible Channel&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Morning, 10am local time:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/rOyca.png&quot; alt=&quot;Morning, 10am local time&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Afternoon, 4pm local time:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/SVIhq.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="669" LastEditorUserId="669" LastEditDate="2014-09-26T16:32:59.710" LastActivityDate="2016-04-11T03:57:00.417" Title="GOES Visible Channel - asymmetry between morning and afternoon" Tags="|remote-sensing|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2539" PostTypeId="2" ParentId="2535" CreationDate="2014-09-26T21:42:15.353" Score="5" Body="&lt;p&gt;This is counterproductive, both ecologically and economically, and is also well beyond the capabilities of current robots.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Ecologically counterproductive&lt;/strong&gt;&lt;br&gt;&#xA;Forests have evolved to live with, and in many cases, to depend on forest fires. Aggressive fire prevention by the US Forest Service and other agencies throughout much of the 20th century resulted in unintended consequences. Many native species need fire to reproduce. For example, the pinecones of lodgepole pines remain sealed shut for years and only open when exposed to the high heat of a forest fire. Decades of active fire suppression led to the replacement of some of those native species by invasive ones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another unintended consequence was making large fires even larger. Some of the most intense fires happened in areas where small fires had been successfully suppressed for a number of years. The resultant buildup of dead wood, brush, and smaller trees gave fires a way to spread to the canopy level, something that didn't happen so often when small fires regularly burned away that lower level of fuel.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Economically counterproductive&lt;/strong&gt;&lt;br&gt;&#xA;One of the biggest fire threats to people is those people who insist on living in forested areas and then let the trees grow right next to their houses. The simplest solution: Don't do that then! The Forest Service and others offer education to homeowners on how to make their homes more fire resistant, and in some cases, polices areas to ensure homeowners are following some minimum standard.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another solution, one not yet adopted by the Forest Service, is an approach taken by the Federal Emergency Management Agency with regard those who live in the most flood-prone areas. After flooding one too many times, FEMA essentially forces homeowners to sell their houses at market value to FEMA. FEMA then promptly tears them down and marks the area as uninsurable. This might appear to be a waste of money, but in the long run it saves FEMA money, and potentially saves lives. Texas and some other states take even more drastic measures with coastal properties. A house is condemned once the coast line has eroded to the point that it is closer than some minimal distance of the house.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;We can't build such robots, yet&lt;/strong&gt;&lt;br&gt;&#xA;The terrain where forests grow is not exactly suitable to robots. Much of the forested land in the contiguous US is mountainous. What isn't mountainous is dotted with bogs, swamps, and lakes. The weather is often rather nasty. An autonomous robot that could navigate and survive through such terrain is far in the future. Adding the ability to clean up terrain is even further in the future.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Aggressive fire suppression requires clearing out shrubs such as chaparral, which is rather tough stuff, dead and down trees that can be several meters in diameter, and small to medium sized non-canopy trees whose trunk can be up to a meter or so in diameter. This is not the job for little goat-sized robots. This is a job for an industrial-sized robot, and ED-209 won't cut it.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-09-26T21:42:15.353" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="2540" PostTypeId="1" CreationDate="2014-09-27T02:45:36.217" Score="6" ViewCount="178" Body="&lt;p&gt;I read somewhere someone someone had the idea to try to move a 'small' iceberg with giant tugboats used to move oil-rigs. I thought if an Iceberg could be moved, why not move it $NORTHWARD$ maybe &lt;em&gt;above the latitude&lt;/em&gt; of where it 'broke' off. Maybe it could be anchored there somehow. Is this feasible?&lt;/p&gt;&#xA;" OwnerUserId="855" LastEditorDisplayName="user889" LastEditDate="2015-01-11T13:52:53.440" LastActivityDate="2015-01-11T13:52:53.440" Title="About moving ice bergs northwards to slow down all the melting a tiny bit. ( Clearing away navigation hazards is a side effect of this.)" Tags="|oceanography|glaciology|human-influence|cryosphere|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2541" PostTypeId="1" CreationDate="2014-09-27T06:19:11.340" Score="11" ViewCount="978" Body="&lt;p&gt;Suppose we spot an Atlantic hurricane very early. How much energy should we expend to alter its track:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;with nuclear detonations (let's forget about the side effects for the moment)?&lt;/li&gt;&#xA;&lt;li&gt;with a large orbital geostationary mirror illuminating say, the subtropical ridge?&lt;/li&gt;&#xA;&lt;li&gt;by any other means (microwave heating in the troposphere?)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h2&gt;References on these and other methods from the NOAA Hurricane FAQ:&lt;/h2&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/C5a.html&quot;&gt;Silver iodide&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/C5b.html&quot;&gt;Aerosols/surface modification&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/C5c.html&quot;&gt;Nukes&lt;/a&gt;, specifically:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A fully developed hurricane can release heat energy at a rate of  $5-20\centerdot10^{13}$ watts and converts less than 10% of the heat into the mechanical energy of the wind. The heat release is equivalent to a 10-megaton nuclear bomb exploding every 20 minutes. According to the 1993 World Almanac, the entire human race used energy at a rate of $10^{13}$ watts in 1990, a rate less than 20% of the power of a hurricane. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/C5d.html&quot;&gt;Water absorbing substances&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/C5e.html&quot;&gt;Surface cooling with icebergs&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/C5f.html&quot;&gt;Expending hurricane's energy&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/C5g.html&quot;&gt;High altitude particulate seeding&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/C5h.html&quot;&gt;Hygroscopic particle seeding&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/C5i.html&quot;&gt;Miscellaneous means&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h2&gt;Why the above-mentioned FAQ isn't enough&lt;/h2&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;It's incomplete (doesn't include heating/illumination from satellites)&lt;/li&gt;&#xA;&lt;li&gt;Doesn't include a fully-developed nuclear scenario&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Has no formula linking time since hurricane formation, energy applied and cross-track difference at landfall on the East Coast&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="269" LastEditorUserId="192" LastEditDate="2014-09-27T15:23:47.973" LastActivityDate="2014-09-27T15:23:47.973" Title="How much energy is needed to alter the path of a hurricane?" Tags="|meteorology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2542" PostTypeId="2" ParentId="2541" CreationDate="2014-09-27T07:50:31.553" Score="7" Body="&lt;p&gt;This is not a complete answer, but offers insights to research of some perspectives of the question you raised.&lt;/p&gt;&#xA;&lt;p&gt;There has been a document recently written about this, &lt;a href=&quot;http://www.atmo.arizona.edu/students/courselinks/spring08/atmo336s2/articles/Hurricanes_control_SciAm_Oct2004.pdf&quot; rel=&quot;noreferrer&quot;&gt;Controlling Hurricanes&#xA;Can hurricanes and other severe tropical&#xA;storms be moderated or deflected?&lt;/a&gt; (Hoffman, 2004). In it, there are several main considerations, one major consideration in relation to your questions is that studies show that changes in the energy available can potentially alter the path of a hurricane.  The studies reported in the article&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;confirms that these massive, chaotic systems are susceptible to&#xA;minor changes in their initial conditions—for instance, the air temperature and&#xA;humidity near the center of the storm and in the surrounding regions&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Using computer simulations of hurricanes, they confirmed that&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;changes in&#xA;precipitation, evaporation and air temperature could alter a&#xA;storm’s path or weaken its winds.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Even though the article suggests one of your suggestions, about microwave heating of the air or the water, this power would be harnessed by satellite based solar panels, the main simulated methods appear not to be a case of adding the energy to the hurricane itself - but rather &lt;em&gt;robbing the hurricane of its energy sources&lt;/em&gt;, examples include&lt;/p&gt;&#xA;&lt;p&gt;Cloud seeding with silver iodide or similar material is suggested, these would promote precipitation, which would rob the eye wall of&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;the water it needs to grow and&#xA;intensify&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Another method, and rather unique is the use of biodegradable oil on the water's surface, specifically&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Biodegradable oil could be distributed across&#xA;the sea surface in the path of a hurricane&#xA;to limit evaporation—the source of a&#xA;storm’s energy&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;A study by Stanford University, reported in the article &lt;a href=&quot;http://news.stanford.edu/news/2014/february/hurricane-winds-turbine-022614.html&quot; rel=&quot;noreferrer&quot;&gt;Offshore wind farms could tame hurricanes before they reach land, Stanford-led study says&lt;/a&gt; (Carey, 2014), suggest by computer modelling that&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;We found that when wind turbines are present, they slow down the outer rotation winds of a hurricane,&amp;quot; Jacobson said. &amp;quot;This feeds back to decrease wave height, which reduces movement of air toward the center of the hurricane, increasing the central pressure, which in turn slows the winds of the entire hurricane and dissipates it faster.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The data indicated that&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In the computer model, by the time Hurricane Katrina reached land, its simulated wind speeds had decreased by 36-44 meters per second (between 80 and 98 mph) and the storm surge had decreased by up to 79 percent.&lt;/p&gt;&#xA;&lt;p&gt;For Hurricane Sandy, the model projected a wind speed reduction by&#xA;35-39 meters per second (between 78 and 87 mph) and as much as 34&#xA;percent decrease in storm surge.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In terms of using a nuclear detonation to stop or divert a hurricane, the author of the article &lt;a href=&quot;http://www.livescience.com/24383-can-you-stop-a-hurricane-by-nuking-it.html&quot; rel=&quot;noreferrer&quot;&gt;Can You Stop a Hurricane by Nuking It?&lt;/a&gt; (2012) describes the potential effectiveness of this method&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;might be about as effective as trying to stop a speeding Buick with a feather.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;mainly due to as you said in your question:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;the same amount of energy released by exploding a 10-megaton nuclear bomb every 20 minutes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;A nuke on water nearby may make the hurricane worse, by heating the water, thus 'feeding' the hurricane.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-09-27T10:18:48.320" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2544" PostTypeId="2" ParentId="2540" CreationDate="2014-09-27T10:37:41.020" Score="14" Body="&lt;p&gt;Some background. The idea of towing ice bergs to provide a source for fresh water in dry climate zones was first proposed in the 1970s by Weeks and Campbell (1973) and Hult and Ostrander (1973). This sparked interest that resulted in several studies published in conferences (Husseiny, 1980; IGS, 1980). The focus of the work was manly on the wastage of ice during transport and of course the technical aspects of towing ice. The main issue, however, concerns the integrity of ice bergs during transport. The mechanics of ice bergs is still poorly understood and it is known that bergs gradually break up. How this is affected by ocean swells and other forces acting upon a berg under tow is still investigated (see a wealth of publications in particularly &lt;a href=&quot;http://www.igsoc.org/journal/&quot;&gt;Journal of Glacology&lt;/a&gt; and &lt;a href=&quot;http://www.igsoc.org/annals/&quot;&gt;Annals of Glaciology&lt;/a&gt;). The idea has, however, not been forgotten and more possible technical solutions are proposed (e.g. &lt;a href=&quot;http://www.fastcompany.com/1755444/watch-tugboat-drag-arctic-iceberg-parched-people-half-world-away-video&quot;&gt;Fast Company&lt;/a&gt;. So while the financial aspect of the process may be calculable, the strength of ice bergs, and the forces acting upon them in the open sea and under tow requires more research before towing could become a reality.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On top of this are legal issues. Who owns the ice? and also how can towing ice berg across busy shipping lines be safe, particularly in the event of a break-up in mid-ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To respond to your specific question on towing northward and anchoring: The towing in any direction is subject to the same issues as described above. Anchoring, the ice bergs will melt and degrade over time so that moorings will continually have to be renewed. Most ice bergs in the north will go through at least one cycle of being caught in seasonal sea ice but eventually will be set free to follow ocean currents in whatever direction they move locally. Since the ocean water will carry some heat, it will not matter where the ice berg is located, it will slowly melt. On top of that is the issue of disintegration since melting will change the shape of the berg and hence its stability and centre of gravity causing stresses within the block to alter. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If one takes a longer-term perspective and ignores the practicalities (incl. costs), moving ice to a place where it melts slower would momentarily decrease the contribution but eventually one would reach a new equilibrium where the same rate of melt water will be contributed and the temporary benefit will be lost. So apart from being highly impractical from all aspects, the longer-term benefits will be nil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hult, J.L. and Ostrander, N.C., 1973. Antarctic icebergs as a global fresh water resource. Rand Corporation, Santa Monica. Report No. R-1255-NSF. 83 pp.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Husseiny, A.A. (ed.) 1978. Iceberg Utilization. Proceedings of the First International Conference, Ames, Iowa, 1977. Pergamon Press, New York. 759 pp.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;IGS (International Glaciological Society), 1980. Proceedings of the Conference on the Use of Icebergs. Annals of Glaciology, 1 136 pp.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Weeks, W.F. and Campbell, W.J., 1973. Icebergs as a fresh-water source: an appraisal. Journal of Glaciology, 12, 65, 207-233.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="81" LastEditDate="2014-09-28T09:59:59.330" LastActivityDate="2014-09-28T09:59:59.330" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2545" PostTypeId="1" AcceptedAnswerId="2547" CreationDate="2014-09-28T21:25:00.027" Score="13" ViewCount="668" Body="&lt;p&gt;Following recent eruption of Mt Ontake and the &lt;a href=&quot;http://www.abc.net.au/news/2014-09-28/more-than-30-hikers-found-in-cardiac-arrest-on-volcano/5774752&quot; rel=&quot;nofollow&quot;&gt;sad news of over 30 people found in 'cardiac arrest'&lt;/a&gt;, why would the eruption cause it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My initial thought would be that the cause of death would normally be suffocation or burns from the hot ash. Is it to do with elements/compounds present in volcanic ash?&lt;/p&gt;&#xA;" OwnerUserId="919" LastEditorUserId="111" LastEditorDisplayName="user889" LastEditDate="2015-07-07T18:14:57.717" LastActivityDate="2020-09-25T04:19:12.707" Title="Why would volcano eruption cause cardiac arrest?" Tags="|volcanology|volcanic-hazard|volcanic-eruption|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2546" PostTypeId="1" AcceptedAnswerId="4539" CreationDate="2014-09-29T00:32:58.433" Score="14" ViewCount="431" Body="&lt;p&gt;When studying the land surface, dry-down periods - periods after rain where the soil moisture is decreasing due to evapotranspiration and drainage - are of great interested, because soil moisture has such a strong effect on nearly every aspect of the land surface (carbon uptake, heat distribution, albedo, etc. etc.).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously dry-downs at different time-scales (and different soil depths) are of interest for different processes. But I was wondering if there was any kind of standardised method for defining dry-down periods. e.g. is it relevant how much rain happened before the event? Or does a small shower in the middle of a long dry-down nullify the event? Or is it all arbitrary and defined differently for each individual piece of research?&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2015-03-17T17:19:26.187" Title="Is there a standard definition of a &quot;dry-down&quot; event in hydrology?" Tags="|hydrology|precipitation|land-surface|soil-moisture|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2547" PostTypeId="2" ParentId="2545" CreationDate="2014-09-29T08:46:42.857" Score="17" Body="&lt;p&gt;Michael's comment is correct, in Japan, according to the article &lt;a href=&quot;http://www.radioaustralia.net.au/international/2014-09-28/japan-volcanic-eruption-mt-ontake-rescuers-find-more-than-30-people-in-cardiac-arrest/1373061&quot;&gt;Japan volcanic eruption: Mt Ontake rescuers find more than 30 people in 'cardiac arrest'&lt;/a&gt; (Radio Australia), state&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Police said the 31 people were found in &quot;cardiopulmonary&quot; arrest on Sunday &lt;strong&gt;but declined to confirm their deaths pending a formal examination, as per Japanese custom.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and more directly, from &lt;a href=&quot;http://www.washingtonpost.com/world/asia_pacific/more-than-30-feared-dead-on-japans-mount-ontake-after-volcano-erupts/2014/09/28/0075781b-52f2-47af-b4ce-7090aac4cc03_story.html&quot;&gt;More than 30 feared dead on Japan's Mount Ontake after volcano erupts&lt;/a&gt; (Washington Post)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;using the terms for heart and lung failure that Japanese authorities employ to describe bodies. People cannot be declared dead in Japan until doctors have examined them.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It is very likely, given how close they were to the eruptive crater and the sudden inhalation of hot volcanic ash, gases and other materials, the victims went into cardiopulmonary arrest due to their lungs being overwhelmed by the sudden quantity.  Additionally, burns, fear, debris could have likely caused shock causing cardiac arrest.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Several case studies from other volcanoes are presented in the article &lt;a href=&quot;http://www.geo.mtu.edu/~raman/papers2/HorwellBaxterBV.pdf&quot;&gt;The respiratory health hazards of volcanic ash:&#xA;a review for volcanic risk mitigation&lt;/a&gt; (Horwell and Baxter, 2005).&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-09-29T09:23:37.640" LastActivityDate="2014-09-29T09:23:37.640" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2548" PostTypeId="2" ParentId="933" CreationDate="2014-09-30T02:52:46.613" Score="3" Body="&lt;p&gt;A part answer to your question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the article &lt;a href=&quot;http://www.nature.com/ngeo/journal/v1/n1/full/ngeo.2007.43.html&quot; rel=&quot;nofollow&quot;&gt;Palaeoceanography: The briny deep&lt;/a&gt; (Martin, 2008), explains the reason for the use of the neodymium ratio as being &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The isotopic signature of a water mass is imparted from weathering of continental material in the region where the water mass sinks below the surface. &lt;strong&gt;Radiogenic Nd isotope values reflect a contribution from relatively young volcanic material, whereas non-radiogenic values are a consequence of inputs from old continental crust.&lt;/strong&gt; The water mass carries its distinctive signature as it circulates through the oceans.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Its stability is described in the paper &lt;a href=&quot;https://darchive.mblwhoilibrary.org/handle/1912/1392&quot; rel=&quot;nofollow&quot;&gt;Temporal stability of the neodymium isotope signature of the Holocene to glacial North Atlantic&lt;/a&gt; (de Flierdt et al. 2006), as being due to the observations that Nd isotopes&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;are not thought to be altered in any significant way by biological processes, and thus can serve as a quasi-conservative water mass tracer.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-09-30T02:52:46.613" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2552" PostTypeId="1" AcceptedAnswerId="2556" CreationDate="2014-10-01T04:13:00.833" Score="11" ViewCount="6845" Body="&lt;p&gt;Let's assume that a ship is traveling on the ocean and it sinks, what is the effect on sea level? Even if the effect is small, would it go up, down or remain the same?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2023-01-09T01:59:55.683" LastActivityDate="2023-01-09T01:59:55.683" Title="What happens to sea level when a ship sinks?" Tags="|oceanography|sea-level|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="2553" PostTypeId="1" CreationDate="2014-10-01T04:19:44.067" Score="18" ViewCount="943" Body="&lt;p&gt;I have been asked the following question for which I have no clear answer:&#xA;What is the relative importance on mixing of the vertical flow of gases (e.g., Oxygen produced by photosynthesis, CO&lt;sub&gt;2&lt;/sub&gt; produced in respiration, methane produce from hydrates) in the ocean water column? How does the mixing compare with physical mixing (e.g., wind, internal wave breaking) and molecular diffusion?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My first thought is that the ocean tends to not be saturated in oxygen and CO&lt;sub&gt;2&lt;/sub&gt;, but is there some outgassing as a result of those processes? The question of methane hydrates is probably more complex and likely has links to climate change.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="543" LastEditDate="2016-02-12T03:33:09.233" LastActivityDate="2016-02-19T00:26:01.533" Title="What is the importance of mixing caused by outgassing in the ocean?" Tags="|oceanography|co2|biogeochemistry|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2554" PostTypeId="2" ParentId="2552" CreationDate="2014-10-01T09:33:43.293" Score="7" Body="&lt;p&gt;The sea level should decrease. Consider a boat before it sinks. It must displace a weight of water equal to the weight of the boat to have neutral buoyancy. The material comprising a boat is more dense than water, thus is less voluminous than the displaced ocean. This displaced ocean volume will be realized as a rise in ocean height. However, once the boat sinks  this volume of water is no longer displaced and this will be realized as a sea level fall. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that the sea level should be higher with a sunken ship than with no ship at all, so this answer depends on a working boat on the ocean surface being replaced with a sunken boat. Also note that the magnitude of sea level rise and falls being distributed across enormous surface area is likely too minuscule to be able to measure (e.g. smaller than instrument error).  &lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="28050" LastEditDate="2014-10-01T14:29:57.723" LastActivityDate="2014-10-01T14:29:57.723" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2555" PostTypeId="1" AcceptedAnswerId="2557" CreationDate="2014-10-01T11:50:23.113" Score="18" ViewCount="893" Body="&lt;p&gt;Aside from the fraction of water stored as ice on land and temperature of the water, are there other factors that change sea level, and if so what are is the magnitudes of the these changes? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, by how much does sediment and soluble matter entering the ocean change sea level? What about volcanoes and tectonic activity? Is there a tendency toward hydrostatic equilibrium where the Earth is entirely covered by an ocean of uniform depth?&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="28050" LastEditDate="2014-10-01T13:21:43.997" LastActivityDate="2017-05-19T12:31:44.550" Title="Are there secondary causes of sea level change?" Tags="|oceanography|sea-level|stratigraphy|erosion|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2556" PostTypeId="2" ParentId="2552" CreationDate="2014-10-01T12:28:10.690" Score="22" Body="&lt;p&gt;It would go down. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to float, an object must displace a volume of fluid that weighs the same as the boat. In the case of a ship, this volume is less than the gross volume of the boat, including the air inside it. That's why it floats with the gunwales comfortably above the water. So when the boat is floating, it displaces some volume &lt;em&gt;V&lt;/em&gt;, so relative sea-level goes up (second panel, below). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/bHskY.png&quot; alt=&quot;A boat displacing water before and after sinking.&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, when the ship is submerged and full of seawater, it displaces a smaller volume than it originally did. If it didn't, it wouldn't have sunk (assuming it hasn't changed in weight).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since it displaces a smaller volume after sinking, relative sea-level must go down. But it will still be higher than it was before the ship was launched.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="23" LastEditDate="2014-10-02T08:28:40.740" LastActivityDate="2014-10-02T08:28:40.740" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2557" PostTypeId="2" ParentId="2555" CreationDate="2014-10-01T12:52:25.270" Score="24" Body="&lt;p&gt;Yes, there are lots of other factors. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Factors affecting sea levels are no different from other natural processes: there is a large number of coupled, non-linear effects, operating on every time scale, and at every length scale, and across many orders of magnitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Wikipedia page &lt;a href=&quot;http://en.wikipedia.org/wiki/Current_sea_level_rise&quot; rel=&quot;noreferrer&quot;&gt;Current sea level rise&lt;/a&gt; lists many of the known processes. And I wrote a blog post, &lt;a href=&quot;http://www.agilegeoscience.com/journal/2011/4/11/scales-of-sea-level-change.html&quot; rel=&quot;noreferrer&quot;&gt;Scales of sea-level change&lt;/a&gt;, a couple of years ago with a long list, mostly drawn from Emery &amp;amp; Aubrey (1991). Here's the table from it:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/hqb0B.png&quot; alt=&quot;Factors affecting global sea levels&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&#xA;Emery, K &amp;amp; D Aubrey (1991). &lt;em&gt;Sea-Levels, Land Levels and Tide Gauges.&lt;/em&gt; Springer-Verlag, New York, 237p.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2017-05-19T12:31:44.550" LastActivityDate="2017-05-19T12:31:44.550" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="2558" PostTypeId="1" CreationDate="2014-10-01T13:57:04.577" Score="12" ViewCount="576" Body="&lt;p&gt;I need it in this format.&#xA;&lt;img src=&quot;https://i.stack.imgur.com/OKIGT.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I went to USGS and IRIS websites but couldn't understand the downloading procedure&lt;/p&gt;&#xA;" OwnerUserId="594" LastEditorUserId="28050" LastEditDate="2014-10-01T14:33:09.723" LastActivityDate="2016-01-30T03:23:22.410" Title="Where and how can seismic data for earthquakes and volcanoes be downloaded?" Tags="|seismology|earthquakes|open-data|data-formats|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2559" PostTypeId="2" ParentId="2555" CreationDate="2014-10-01T14:50:32.597" Score="7" Body="&lt;p&gt;&lt;a href=&quot;http://bit.ly/1doBprE&quot;&gt;This link&lt;/a&gt; is a scientific talk by geoscientist &lt;a href=&quot;http://environment.harvard.edu/about/faculty/jerry-x-mitrovica&quot;&gt;Jerry Mitrovica&lt;/a&gt; (&lt;a href=&quot;http://www.harvard.edu/&quot;&gt;Harvard University&lt;/a&gt;) called 'Sea Level Fingerprints of Ice Sheet Collapse'. It's about an hour long, fairly technical, and focused on ice sheet contributions to sea level change (it was for an audience of other scientists), and has some good background related to this question. I highly recommend watching if you have the time. &lt;/p&gt;&#xA;" OwnerUserId="931" LastEditorUserId="611" LastEditDate="2014-10-01T21:50:35.233" LastActivityDate="2014-10-01T21:50:35.233" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2560" PostTypeId="1" AcceptedAnswerId="2565" CreationDate="2014-10-01T17:47:48.147" Score="7" ViewCount="1397" Body="&lt;p&gt;There is a discussion about whether touching a stalagmite or a stalactite would stop it from growing or not: &lt;a href=&quot;https://answers.yahoo.com/question/index?qid=20090629155053AAYFhCM&quot;&gt;https://answers.yahoo.com/question/index?qid=20090629155053AAYFhCM&lt;/a&gt; .&#xA;The results are that the oil on human body does prevent a stalagmite or a stalactite from growing, a short while though. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is, how long does it takes for the oil to completely vanish and allow the stalagmite or stalactite to resume growing. &lt;/p&gt;&#xA;" OwnerUserId="933" LastActivityDate="2014-10-02T01:19:33.407" Title="How long does one touch on a stalagmite/stalactite lasts?" Tags="|geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2561" PostTypeId="1" CreationDate="2014-10-01T09:12:48.850" Score="5" ViewCount="211" Body="&lt;p&gt;The Coriolis force is not a real force, but depending on the reference system and how it does refer to an inertial system. Could this Coriolis force as widely used in atmospheric/climate modeling be replaced by an explicit force eg from sun gravitation and would this give the same results?&lt;/p&gt;&#xA;" OwnerDisplayName="tom98765x" LastEditorUserId="111" LastEditDate="2014-10-01T20:25:21.400" LastActivityDate="2014-10-03T15:06:07.117" Title="coriolis force in atmospheric/ocean modeling" Tags="|atmosphere|ocean|coriolis|fluid-dynamics|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2562" PostTypeId="2" ParentId="2561" CreationDate="2014-10-01T10:49:02.097" Score="6" Body="&lt;p&gt;If your question is: I have an equation with force term $F(x,t)$, and suppose that $F(x,t)$ is caused by effect A, then will the solution of the equation be the same as if the force $F(x,t)$ had been caused by effect B, then the answer is of course &quot;yes&quot;. Same force (i.e., same magnitude, same direction) will always cause the same reaction of the system, regardless of where this force comes from.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, the coriolis force has a very specific form and you will have difficulty finding any other physical effect that would lead to a force term that happens to have the exact same form.&lt;/p&gt;&#xA;" OwnerUserId="5259" OwnerDisplayName="Wolfgang Bangerth" LastActivityDate="2014-10-01T10:49:02.097" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2563" PostTypeId="2" ParentId="2561" CreationDate="2014-10-01T20:42:08.997" Score="7" Body="&lt;p&gt;The Coriolis acceleration is only present in a rotating reference frame as is the case with Earth. The Coriolis effect is caused by Earth's rotation and the inertia of the mass experiencing the effect. If you are in an inertial frame of reference, thus non-accelerating, there will be no Coriolis effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's assume that you are capable of modeling the motions on Earth as part of a Solar System model with the frame of reference centered at the Sun (and assume that it is non-accelerating), then there will be no need to include the Coriolis effect.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-10-01T20:42:08.997" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2564" PostTypeId="2" ParentId="2561" CreationDate="2014-10-01T23:23:43.900" Score="10" Body="&lt;p&gt;Here are your choices with regard to modeling the atmosphere. There aren't many, and only one of them makes sense.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Model the atmosphere from the perspective of an inertial frame of reference.&lt;br&gt;&#xA;Good luck with that! As an advisor told me decades ago, &quot;Name one!&quot; It's certainly not an Earth-centered frame; the Earth is orbiting the Sun. It's certainly not Sun-centered frame; the Sun is orbiting Jupiter, Saturn, Uranus, and Neptune. It's certainly not the solar system barycenter (center of mass); the solar system is orbiting the Milky Way. The Milky Way barycenter? Nope. The Milky Way and the Andromeda galaxy are accelerating toward one another. No matter how far afield we look, we see gravity (and even further afield, metric expansion of space) that hides this inertial frame from us.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Use a non-rotating frame centered at the solar system barycenter.&lt;br&gt;&#xA;The International Celestial Reference Frame is one such frame. This is more or less a constructible frame. Here we either ignore or account for the acceleration toward the center of the Milky Way, the Andromeda galaxy, and stuff further afield. It does makes sense to ignore those extraneous accelerations; they are very, very tiny, and the variation across the solar system is tinier yet. There's another issue with any such construction. The ICRF almost certainly is rotating. The predecessor of the ICRF, the J2000 frame: Scientists now know it was rotating. The same goes for the predecessor of the J2000 frame, the B1950 frame. In fact, scientists &lt;em&gt;know&lt;/em&gt; the ICRF is rotating. The ICRF has been upgraded to ICRF version 2.0. And that too is rotating. Scientists just don't know how much.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Use a non-rotating frame centered at the Earth's center of mass (aka Earth-centered inertial).&lt;br&gt;&#xA;Even if the ICRF was &lt;em&gt;perfect&lt;/em&gt;, there is no way one can reasonably model the Earth's atmosphere in a computer program from the perspective of such a frame. The length and velocity scales needed to properly model the atmosphere and the length and velocity scales using a solar system barycenter frame just don't match. Oil and water. Even worse, it's a Sesame Street moment! (&quot;One of these things is not like the others, One of these things just doesn't belong.&quot;)&lt;br&gt;&#xA;The thing that doesn't belong is the solar system barycenter. The only reasonable way to model the Earth's atmosphere is to use an Earth-centered perspective. Now a computer program is starting to have a chance to represent the atmosphere, and do so in a way that is computationally feasible. An Earth-centered frame is accelerating, but we can handle that. We can pretend that $\vec F=m \vec a$ still applies. This result in fictitious tidal accelerations. It's not a problem. Physics still works.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Use an Earth-centered, Earth-fixed reference frame.&lt;br&gt;&#xA;A problem remains with the Earth-centered inertial frame described in option #3. The Earth, the atmosphere, and the oceans are rotating, and at different rates. This means that &quot;starting to have a chance&quot; was a bit overoptimistic. It makes much, much more sense to use a frame that rotates with the Earth. This adds even more fictitious forces, the centrifugal and Coriolis forces, but once again, that's not a problem. In fact, this simplifies things to the point where meteorologists do finally have a chance to represent the atmosphere in a way that is computationally feasible.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Option #4, the one that requires fictitious third body forces (aka tidal forces), fictitious centrifugal forces, and fictitious Coriolis forces, is the only option that makes a bit of sense from the perspective of modeling the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2014-10-03T15:06:07.117" LastActivityDate="2014-10-03T15:06:07.117" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2565" PostTypeId="2" ParentId="2560" CreationDate="2014-10-02T01:11:43.357" Score="5" Body="&lt;p&gt;The duration cannot be estimated as it is dependent upon many other factors, such as the diameter of stalagmite/stalactite, its age etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Normally these are formed in limestone caves and sometime in salt mines as well. &lt;/p&gt;&#xA;" OwnerUserId="935" LastEditorUserId="935" LastEditDate="2014-10-02T01:19:33.407" LastActivityDate="2014-10-02T01:19:33.407" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2566" PostTypeId="1" CreationDate="2014-10-02T07:12:33.817" Score="23" ViewCount="2750" Body="&lt;p&gt;It is said that the Amazon rainforest receives &lt;a href=&quot;https://en.wikipedia.org/wiki/Amazon_rainforest#History&quot;&gt;up to half of its nutrients&lt;/a&gt; via &lt;a href=&quot;https://en.wikipedia.org/wiki/Mineral_dust&quot;&gt;mineral dust from the Sahara desert&lt;/a&gt;. But a few thousand years ago, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Neolithic_Subpluvial&quot;&gt;Sahara desert was much more fertile&lt;/a&gt;, having a savannah-like environment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Did this mean that the nutrient transfer to the Amazon did not take place during this time? If so, what did the Amazon look like?&lt;/p&gt;&#xA;" OwnerUserId="85" LastEditorUserId="111" LastEditDate="2015-03-02T17:55:14.497" LastActivityDate="2021-07-12T08:35:43.957" Title="What was the Amazon like during Green Sahara?" Tags="|paleoclimatology|amazon|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2567" PostTypeId="2" ParentId="2566" CreationDate="2014-10-02T09:25:48.870" Score="18" Body="&lt;p&gt;According to the article &lt;a href=&quot;http://www.mpimet.mpg.de/fileadmin/staff/claussenmartin/publications/claussen_al_africa-hotspot_igbp_02.pdf&quot;&gt;Africa: Greening of the Sahara&lt;/a&gt; (Claussen et al.), the 'Green Sahara, occurred during the &lt;a href=&quot;http://en.wikipedia.org/wiki/Holocene_climatic_optimum&quot;&gt;Holocene climatic optimum&lt;/a&gt;, occurring at the same time as the  &quot;African Humid Period&quot;, also similar ages to the events mentioned in your 3rd link.  All occurring during the mid Holocene&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the same time in the Amazon region, according to the article &lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1693334/pdf/15212099.pdf&quot;&gt;Responses of Amazonian ecosystems to climatic&#xA;and atmospheric carbon dioxide changes since the&#xA;last glacial maximum&lt;/a&gt; (Mayle et al. 2004), was&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;reduced precipitation in the Early–Mid-Holocene (ca. 8000–3600 years ago) caused widespread,&#xA;  frequent fires in seasonal southern Amazonia, causing increased abundance of drought-tolerant dry forest&#xA;  taxa and savannahs in ecotonal areas.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Although, this effect was not uniform over the entire Amazonian Basin, the authors conclude from pollen, charcoal and other samples, that the Amazon Basin had far less precipitation (up to 40 less in places), which caused&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;increased fires and consequently greater ecosystem&#xA;  disturbance, which would be expected to have caused&#xA;  structural as well as compositional changes to plant communities,&#xA;  such as expansion of drought-tolerant lianas and&#xA;  semi-deciduous taxa within forests and expansion of savannahs&#xA;  at forest–savannah ecotones. Populations of coldadapted&#xA;  species (e.g. Podocarpus) were largely eliminated&#xA;  from the Amazon lowlands during this interval, and cloud&#xA;  forests on the eastern flanks of the Bolivian Andes diminished&#xA;  while open, grass-dominated ecosystems expanded.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-10-02T09:25:48.870" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2568" PostTypeId="1" AcceptedAnswerId="2569" CreationDate="2014-10-02T12:39:34.173" Score="17" ViewCount="2977" Body="&lt;p&gt;Urban areas these days can be quite large, and they can have strong effects on the environment: the &lt;a href=&quot;http://en.wikipedia.org/wiki/Urban_heat_island&quot;&gt;urban heat island&lt;/a&gt; effect being the most obvious, but there may be other, more subtle effects. The relative lack of vegetation and drainage might make them drier, the concentration of high-rise buildings might approximate the effect of small hills, and there's also the air pollution they produce.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus I suspect that large urban areas might have an effect on rain, but exactly how? Do they cause more rain or less around them? What about any effects downwind?&lt;/p&gt;&#xA;" OwnerUserId="85" LastActivityDate="2015-05-02T11:43:50.593" Title="How do urban areas affect rain?" Tags="|meteorology|precipitation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2569" PostTypeId="2" ParentId="2568" CreationDate="2014-10-02T13:05:01.440" Score="13" Body="&lt;p&gt;In a study conducted in Taiwan &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/2010JAMC2504.1&quot;&gt;Impact of the Urban Heat Island Effect on Precipitation over a Complex Geographic Environment in Northern Taiwan&lt;/a&gt; (Lin et al. 2011), found that by observations that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The UHI effect plays an important role in perturbing thermal and dynamic processes; it affects the location of thunderstorms and precipitation over the complex geographic environment in northern Taiwan.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Hance, the situation and potential models of the distribution of rainfall are further complicated by the surrounding topography.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, NASA's Earth Observatory page &lt;a href=&quot;http://earthobservatory.nasa.gov/Features/UrbanRain/urbanrain2.php&quot;&gt;The Impact of City Landscapes on Rain&lt;/a&gt; presents 3 hypotheses for urban effects on rainfall, paraphrased below:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;As you mentioned, the Urban Heat Island, forms a bubble of warmer air and potentially creates atmospheric instability, resulting in&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;as the city-warmed air rises, it cools and forms rain-producing clouds that soak the area downwind.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;The buildings and other structures cause a disruption to the ambient air flow, resulting in&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the city’s buildings provide a source of lift to push warm, moist, surface air into the cooler air above it, where it can develop into rain clouds.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;Similar to no.2, the buildings split the flow of air around the warmer city, these parcels of air return together on the other side:&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;When the two halves of the storm come back together downwind of the city, the air is pushed up like the two colliding trains. The rising air forms rain clouds.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;When I did studies of the effects of aerosols (particularly particulate matter) in urban environments, there were many observations to suggest that some particulate matter could potentially become the &lt;a href=&quot;http://en.wikipedia.org/wiki/Cloud_condensation_nuclei&quot;&gt;cloud condensation nuclei&lt;/a&gt; that changes cloud cover and hence rainfall patterns.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-10-02T13:05:01.440" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2570" PostTypeId="1" AcceptedAnswerId="2572" CreationDate="2014-10-02T00:59:14.880" Score="8" ViewCount="9515" Body="&lt;p&gt;In &quot;Deep Impact&quot;, the president says that &quot;New York City, Boston, Atlanta, Philadelphia, all will be destroyed&quot;. New York and Boston are on the water and would be in danger from a tsunami of any size, Philadelphia is 39 feet above sea level and 50 miles inland. Atlanta is over 200 miles inland and between 750 and 1100 feet above sea level. Would an impact event of the size imagined in the movie actually send a wave that far inland and that far up? Would the natural topography of the region (lots of small hills) affect the wave?&lt;/p&gt;&#xA;" OwnerUserId="4625" OwnerDisplayName="philosodad" LastEditorUserId="20" LastEditDate="2014-10-02T20:33:16.907" LastActivityDate="2021-11-23T01:12:31.570" Title="Is Atlanta too far inland and too far above sea level to be affected by the comet in &quot;Deep Impact&quot;?" Tags="|tsunami|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2571" PostTypeId="2" ParentId="2570" CreationDate="2014-10-02T01:30:56.087" Score="0" Body="&lt;p&gt;Georgia is a fairly flat state, well known for it's extensive wetlands (swamps, y'all), particularly the Great Dismal Swamp. The Northeastern part of the state is part of the Appalachian and Blue Ridge mountains, but these are very old, low-rolling mountains (unlike the high, sharp peaks of the rockies). So the land slopes down from the North-Northeast to the Atlantic coast in the West-Southwest. Atlanta is pretty far inland, but the land South and East is essentially a ramp leading down to the coast. I imagine it's quite possible for a tidal wave to reach Atlanta.&lt;/p&gt;&#xA;" OwnerDisplayName="Joe L." LastActivityDate="2014-10-02T01:30:56.087" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2572" PostTypeId="2" ParentId="2570" CreationDate="2014-10-02T01:34:51.347" Score="13" Body="&lt;p&gt;Tsunamis form as a series of moderate amplitude, long interval waves that travel away from the initial impact.  The first of these waves has the highest amplitude of the initial waves, and becomes the 'big one' later. Subsequent waves are caused by water rushing into the void created by the initial impact, bouncing off of each other, and starting the next wave out.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the radius of the impact waves increases, the power in each wave gets spread out over a larger and larger circumference, at a rate of $2πr$.  This is a steady geometric decrease in the power any given portion of the wave has.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As these waves start to reach shallow water, the waves in front begin to slow down.  This causes the waves behind them to become part of the tsunami.  This build up continues until you reach land.  Once at land, no more power is being introduced into the wave, no more water is being pulled in.  What you see is what you've got at this point.  None of the follow up waves will go anywhere near as far inland as this initial wave.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To elaborate, following landfall, the tsunami would encounter:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The barrier islands to Georgia's east protect it from most severe storms.  Their arrangement would also introduce an interference pattern into the wave that would incline the big tsunami to spread out more.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Beyond that, there is a large, flat area of low elevation where the wave would travel easily, but it would lose a large percentage of its power crossing this area.  Once again, the wave is losing power as it spreads.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Next, you get to the continental shelf that separates North Georgia from South Georgia.  In a rather sharp increase, land goes from a few hundred feet above sea level to, as you mentioned, 750+ feet.  That is one steep hill to climb for an old, tired tsunami.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Without subjecting this to a full simulation I can't be certain, but I think that any impact capable of creating a tsunami that could reach Atlanta would be completely unsurvivable.  Some of the simplest forms of life might make it, but everything else would be gone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That does not mean that Atlanta wouldn't suffer substantial damage from other factors, such as all of the water launched into the air by the impact of a red hot flaming rock and any chunks of that comet that might break off from the friction of passing through the atmosphere, but right now Atlanta is pretty safe from tsunamis.&lt;/p&gt;&#xA;" OwnerDisplayName="user62707" LastEditorUserId="20" LastEditDate="2014-10-02T20:34:33.857" LastActivityDate="2014-10-02T20:34:33.857" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2573" PostTypeId="1" CreationDate="2014-10-03T04:12:44.347" Score="10" ViewCount="3370" Body="&lt;p&gt;The &lt;a href=&quot;http://geology.com/stories/13/volcanic-explosivity-index/&quot; rel=&quot;noreferrer&quot;&gt;Volcanic Explosivity Index (VEI)&lt;/a&gt; is a way of measuring the relative explosiveness of volcanic eruptions, allowing for comparisons between volcanoes.   According to the &lt;a href=&quot;http://volcanoes.usgs.gov/images/pglossary/vei.php&quot; rel=&quot;noreferrer&quot;&gt;USGS Volcanic Hazards page&lt;/a&gt;, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The VEI uses several factors to assign a number, including volume of erupted pyroclastic material (for example, ashfall, pyroclastic flows, and other ejecta), height of eruption column, duration in hours, and qualitative descriptive terms.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Measurements of the ejecta allows an estimate of the VEI of long past eruptions to be made.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As can be seen in the following scale (USGS):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/MjGTi.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The USGS also state that each interval representing&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;an increase of about a factor of 10 in the volume of erupted tephra.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Some eruptions are massive, the largest according to &lt;a href=&quot;http://geology.com/stories/13/volcanic-explosivity-index/&quot; rel=&quot;noreferrer&quot;&gt;Geology.com&lt;/a&gt; was Wah Wah Springs about 30 million years ago, releasing somewhere around 5500 cubic kilometre - this is classified as a VEI 8.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given the scale increases by a factor of 10x the amount of ejecta, my question is, &lt;strong&gt;what are the geological events or precursors that would result in a VEI level 9 eruption (i.e. volume of ejecta greater than 10,000 cubic kilometres)?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-11-18T09:29:33.373" LastActivityDate="2017-02-01T00:33:35.003" Title="What geological events could cause a Volcanic Explosivity Index (VEI) level 9 eruption?" Tags="|volcanology|vei|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2574" PostTypeId="5" CreationDate="2014-10-03T11:53:29.993" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-10-03T11:53:29.993" LastActivityDate="2014-10-03T11:53:29.993" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2575" PostTypeId="4" CreationDate="2014-10-03T11:53:29.993" Score="0" Body="Volcanic Explosivity Index, a comparative measurement of volcanic eruptions based on the amount of ejecta and other observations (if possible)." OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-10-03T16:07:39.837" LastActivityDate="2014-10-03T16:07:39.837" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2576" PostTypeId="5" CreationDate="2014-10-03T11:55:39.043" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-10-03T11:55:39.043" LastActivityDate="2014-10-03T11:55:39.043" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2577" PostTypeId="4" CreationDate="2014-10-03T11:55:39.043" Score="0" Body="For questions that relate to Earth's natural satellite." OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-10-03T16:07:23.073" LastActivityDate="2014-10-03T16:07:23.073" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2578" PostTypeId="5" CreationDate="2014-10-03T11:58:18.660" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-10-03T11:58:18.660" LastActivityDate="2014-10-03T11:58:18.660" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2579" PostTypeId="4" CreationDate="2014-10-03T11:58:18.660" Score="0" Body="The process where denser oceanic crust is forced under continental crust.  These convergent boundaries are sites for volcanic arcs." OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-10-03T16:07:34.250" LastActivityDate="2014-10-03T16:07:34.250" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2580" PostTypeId="5" CreationDate="2014-10-03T12:00:55.483" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-10-03T12:00:55.483" LastActivityDate="2014-10-03T12:00:55.483" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2581" PostTypeId="4" CreationDate="2014-10-03T12:00:55.483" Score="0" Body="Naturally forming sedimentary calcium carbonate. Often contains fossils, indicative of a past marine environment." OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-10-03T16:07:28.977" LastActivityDate="2014-10-03T16:07:28.977" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2582" PostTypeId="2" ParentId="2526" CreationDate="2014-10-03T16:45:21.223" Score="8" Body="&lt;p&gt;First, let's explain what compressibility is. &lt;a href=&quot;http://en.wikipedia.org/wiki/Compressibility&quot; rel=&quot;nofollow noreferrer&quot;&gt;Compressibility&lt;/a&gt; is defined as a measure of the relative volume change of a parcel of fluid as a response to a pressure change. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I calculate the compressibility of seawater using Matlab and the &lt;a href=&quot;http://www.marine.csiro.au/datacentre/processing.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;seawater package&lt;/a&gt; (equivalent to &lt;a href=&quot;http://agris.fao.org/agris-search/search.do?recordID=AV20120150138&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fofonoff &amp;amp; Millard, 1983&lt;/a&gt;), I obtained that the compressibility increases at cold temperatures for salty, brackish, and fresh water. In fact, water has a minimum compressibility at 46.5°C (&lt;a href=&quot;http://dx.doi.org/10.1063%2F1.1679903&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fine &amp;amp; Millero, 1973&lt;/a&gt;). As pressure increases the compressibility decreases for any of the salinities considered. &#xA;&lt;img src=&quot;https://i.stack.imgur.com/DsUB4.png&quot; alt=&quot;Compressibility for a range of pressures and temperatures&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As can be seen in the figure the compressibility is maximum at low temperatures for any salinity (not just seawater) and pressure. So in general, the compressibility of water is maximum at low temperatures due to the internal structure of water. The inverse relationship with temperature seems well accepted (&lt;a href=&quot;http://dx.doi.org/10.1063%2F1.1679903&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fine &amp;amp; Millero, 1973&lt;/a&gt;) and has a direct relation with other properties like the speed of sound.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a typical liquid, the compressibility at low temperatures is reduced as the structure becomes more compact. In water, there is a change at low temperatures toward more open-structure &lt;a href=&quot;http://www1.lsbu.ac.uk/water/clusters.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;clusters&lt;/a&gt; (expanded icosahedral water cluster) versus denser clusters (collapsed icosahedral water cluster). As the water structure at lower temperatures is more open, the capacity for it to be compressed increases. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As cold liquid water is heated it shrinks, it becomes less easy to compress, the speed of sound within it increases, gases become less soluble and it is easier to heat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The compressibility above is calculated using the formula in the figure (same as in the &lt;a href=&quot;http://en.wikipedia.org/wiki/Compressibility&quot; rel=&quot;nofollow noreferrer&quot;&gt;wiki article&lt;/a&gt;) and I have included the code to reproduce the results:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;T=-2:1:30;&#xA;P=0:10:1000;&#xA;S=35;&#xA;for i=1:length(T)&#xA;    for j=1:length(P)&#xA;        dens(i,j)=sw_dens(S,T(i),P(j));&#xA;        dens15(i,j)=sw_dens(15,T(i),P(j));&#xA;        dens0(i,j)=sw_dens(0,T(i),P(j));&#xA;    end&#xA;end&#xA;spvo=1./dens;&#xA;spvo15=1./dens15;&#xA;spvo0=1./dens0;    &#xA;for i=1:length(T)&#xA;    for j=1:length(P)-1&#xA;%        Ev2(i,j)=-(1./spvo(i,j))*(spvo(i,j+1)-spvo(i,j))./(P(j+1)-P(j));&#xA;        Ev35(i,j)=(1-spvo(i,j+1)/spvo(i,j))/(P(j+1)-P(j));&#xA;        Ev15(i,j)=(1-spvo15(i,j+1)/spvo15(i,j))/(P(j+1)-P(j));&#xA;        Ev0(i,j)=(1-spvo0(i,j+1)/spvo0(i,j))/(P(j+1)-P(j));&#xA;    end&#xA;end&#xA;figure(1);clf&#xA;for j=[1,20,100]&#xA;    line(T,Ev35(:,j),'Color','k','LineWidth',2);&#xA;    line(T,Ev15(:,j),'Color','b','LineWidth',2);&#xA;    line(T,Ev0(:,j),'Color','r','LineWidth',2);axtt&#xA;end&#xA;text(T(20),Ev35(20,1),['P=',num2str(P(2)),'dbar'])&#xA;text(T(20),Ev35(20,20)*.99,['P=',num2str(P(21)),'dbar'])&#xA;text(T(20),Ev35(20,100)*.98,['P=',num2str(P(101)),'dbar'])&#xA;text(T(15),Ev0(15,1),['P=',num2str(P(2)),'dbar'],'Color','r')&#xA;text(T(15),Ev0(15,20)*.99,['P=',num2str(P(21)),'dbar'],'Color','r')&#xA;text(T(15),Ev0(15,100)*.99,['P=',num2str(P(101)),'dbar'],'Color','r')&#xA;xlabel('Temperature (degC) ')&#xA;ylabel('Compressibility (1/dbar) ')&#xA;legend('35 PSU','15 PSU','0 PSU')    &#xA;text(7,5e-6,'$c_w=-{1\over V}({dV\over dp})$','Interpreter','latex','FontSize',20,'FontWeight','bold')&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2014-10-06T17:40:15.997" LastActivityDate="2014-10-06T17:40:15.997" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2583" PostTypeId="1" AcceptedAnswerId="3023" CreationDate="2014-10-04T07:16:33.247" Score="15" ViewCount="412" Body="&lt;p&gt;According to NASA (and many other sources), &lt;a href=&quot;http://www.nasa.gov/topics/earth/features/japanquake/earth20110314.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Japan Quake May Have Shortened Earth Days, Moved Axis&lt;/a&gt; and in the answers to the question here &lt;a href=&quot;https://earthscience.stackexchange.com/questions/1001/what-geophysical-events-can-temporarily-increase-the-earths-rate-of-rotation&quot;&gt;What geophysical events can (temporarily) increase the Earth's rate of rotation?&lt;/a&gt;, that major earthquakes result in a slight shift in the length of the day, from NASA:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;calculations indicate that by changing the distribution of Earth's mass, the Japanese earthquake should have caused Earth to rotate a bit faster, shortening the length of the day by about 1.8 microseconds (a microsecond is one millionth of a second).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Past great earthquakes, such as the 8.8 in Chile in 2010 and the 9.1 Sumatra in 2004 have caused similar rotational 'wobbles'.  The NASA article states that the earthquake's magnitude, location and dynamics result in the orbital 'wobbles'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How are Earth's rotational changes due to large earthquake calculated, and especially distinguished from oceanic and atmospheric effects?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-12-11T19:14:27.447" Title="How are Earth's rotational changes due to large earthquakes calculated?" Tags="|geophysics|earthquakes|earth-rotation|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2585" PostTypeId="1" AcceptedAnswerId="2598" CreationDate="2014-10-04T19:09:34.890" Score="14" ViewCount="1702" Body="&lt;p&gt;Odd question, but what data would be needed to to calculate how far winds will carry a strong odor (such as the smells of a restaurant, pizza parlor or burning wood/building?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is wind direction and wind speed. But how does one measure the strength of an odor and predict how far it will travel or how far the winds will carry it before it disappears?&lt;/p&gt;&#xA;" OwnerUserId="945" LastEditorUserId="124" LastEditDate="2014-10-04T20:44:31.563" LastActivityDate="2014-10-18T08:06:33.510" Title="How can odor travel be tracked" Tags="|meteorology|measurements|wind|pollution|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2586" PostTypeId="1" AcceptedAnswerId="2675" CreationDate="2014-10-05T05:54:51.330" Score="24" ViewCount="4303" Body="&lt;p&gt;There have been numerous episodes of mountain building in Earth's geological history, particularly through the super-continent cycle.  Many mountains and mountain ranges have been eroded, as mentioned in the similar question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2290/determining-the-paleoelevation-of-mountain-ranges&quot;&gt;Determining the paleoelevation of mountain ranges&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are believed to be the tallest mountain ranges in Earth's geological past?  Additionally, what evidence is there to support these palaeoelevations?&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-11-18T11:44:21.233" Title="What were the tallest mountain ranges in Earth's geological past?" Tags="|mountains|geography|paleogeography|isostasy|mountain-building|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2587" PostTypeId="1" AcceptedAnswerId="2588" CreationDate="2014-10-06T11:46:28.887" Score="18" ViewCount="2218" Body="&lt;p&gt;I know this is a very simple or naive question but am just being curious. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How would the global temperature change if all vehicles stopped for a whole year?&lt;/p&gt;&#xA;" OwnerUserId="948" LastEditorUserId="87" LastEditDate="2014-11-19T15:11:11.287" LastActivityDate="2014-11-19T15:11:11.287" Title="What happens to global temperature when we stop all the vehicles for a year?" Tags="|temperature|global-warming|pollution|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2588" PostTypeId="2" ParentId="2587" CreationDate="2014-10-06T13:36:53.807" Score="13" Body="&lt;p&gt;There are two factors to be aware of: First, cars (and all road vehicles) account for only a fraction of human CO&lt;sub&gt;2&lt;/sub&gt; output. Off-hand I've a feeling it is about a quarter or a third although I don't have the exact figure handy. That is, stop all cars, and atmospheric CO&lt;sub&gt;2&lt;/sub&gt; would continue to rise, albeit it at a lower rate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second, the atmosphere/ocean temperatures lag the atmospheric CO&lt;sub&gt;2&lt;/sub&gt; content. Therefore even if humans stopped all CO&lt;sub&gt;2&lt;/sub&gt; emissions, temperatures would continue to rise (although they would eventually stop, and the rate of increase would not get any worse). There was an article in &lt;em&gt;Geoscientist&lt;/em&gt; about 5 years ago that compared total anthropogenic CO&lt;sub&gt;2&lt;/sub&gt; emissions to those of the PETM (Paleogene-Eocene Thermal Maximum) which were of a similar level. The Earth recovered from that little incident but it took over 100ka, and not before there were tropical plants at the North Pole (admittedly the starting temperature was higher than today).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ongoing research has started to draw in other earlier events - even the Permian-Triassic. &#xA;It is beginning to appear that the level of CO&lt;sub&gt;2&lt;/sub&gt; itself isn't so important, but the rate of increase is. Temperatures rise too quickly (and ocean acidification occurs too quickly) for the various feedback systems to correct. Hence mass extinctions. Research is definitely ongoing, but this is where the scary (to a geologist) scenarios start to appear...&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorUserId="28050" LastEditDate="2014-10-06T16:47:59.283" LastActivityDate="2014-10-06T16:47:59.283" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="2589" PostTypeId="2" ParentId="2587" CreationDate="2014-10-06T13:40:31.693" Score="15" Body="&lt;p&gt;Not much at first. The damage has already been done. Humanity has added at least 100 gigatonnes of carbon to the atmosphere since the start of the industrial age. Natural sequestration of that excess carbon is a slow process. Suppose &lt;strong&gt;all&lt;/strong&gt; human production of carbon ceases (and note that vehicular production of CO&lt;sub&gt;2&lt;/sub&gt; is but a fraction of the total). It will take centuries to return to pre-industrial levels, and temperatures will continue to rise for decades to come.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Humanity will not countenance a decree to stop using vehicles. You would somehow need to magically dispense the laws of physics, at least those that pertain to internal combustion engines. Food shipments would stop. Riots would ensue within a week of your use of your magic wand.  Your magic want is a death sentence for a huge portion of humanity. People will die in droves. Killing off 90% of humanity is of course one long term solution to the anthropogenic warming problem. It's not a very nice solution.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-10-06T13:40:31.693" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2590" PostTypeId="2" ParentId="334" CreationDate="2014-10-06T22:16:15.233" Score="11" Body="&lt;p&gt;First of all, your statement implies that volcanism didn't occur in Troodos. That is not true. Troodos was even referred to as &quot;Troodos Volcano&quot; once in Miyashiro's 1973 &lt;a href=&quot;http://dx.doi.org/10.1016/0012-821X(73)90118-0&quot; rel=&quot;noreferrer&quot;&gt;article&lt;/a&gt; about Troodos.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A geological map of Cyprus clearly shows that a large portion of the ophiolite is composed of lavas (volcanic) and dykes (sub-volcanic):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/RWUEn.jpg&quot; alt=&quot;Geological map of Cyprus&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;(&lt;a href=&quot;http://www.moa.gov.cy/moa/gsd/gsd.nsf/dmlGeoMap_en/dmlGeoMap_en&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note the red, brown and pink colors. This is however not the arc volcanism you were referring to but rather ocean floor volcanism in a spreading center setting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for your question, why there isn't any arc volcanism in Troodos, the answer is simply that it wasn't hot enough. Let's put the question of where the water comes from aside, and concentrate on what happens when water meets an ultramafic rock, which is what mantle rocks are.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/CMnjY.jpg&quot; alt=&quot;Metamorphism of ultramafic rocks&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;(&lt;a href=&quot;http://www.geol.ucsb.edu/faculty/hacker/geo102C/lectures/part5.html&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see that serpentine is stable at temperatures lower than 600°C, and even lower at (the more relevant for our case) low pressures. At higher temperatures serpentine is not stable anymore and the stable mineral is olivine (a rock forming mineral in lherzolite and harzburgite). Olivine is a dry mineral, so what happens to all the water? The water acts to lower the temperature needed to melt the mantle rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see the dry versus the wet solidus (the temperature in which a rock begins to melt) in the following diagram.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/b8ST1.gif&quot; alt=&quot;Solidi&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to sum it up, serpentinite forms when water reacts with ultramafic rocks at low temperature, for example when seawater infiltrates the mantle rocks, or when fluids from the subducted dehydrated slab reach the colder shallow mantle rocks. Melting and consequently arc volcanism occurs for example when fluids from the subducted dehydrated slab rise to deep and hot mantle rocks and suppress the melting temperature to below the ambient temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are several reasons that the mantle rocks in Troodos were &quot;cold&quot; enough for this to occur. First of all, you are talking about very shallow rocks, very close to the plutonic section of the ophiolite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/pnLDz.gif&quot; alt=&quot;Isotherms&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;(&lt;a href=&quot;http://specialpapers.gsapubs.org/content/403/147&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see that shallow mantle rocks are in the 300-500°C range. The arc volcanoes that you see in that figure are situated above the areas where fluids from the subducting slab can infiltrate hot (1000ish°C) mantle rocks. So you can use the Japan Sea as an analogue for Troodos in this case. Now, it is true that temperatures were likely higher because magmatic activity &lt;em&gt;did occur&lt;/em&gt; in Troodos, but as Troodos was a slow-spreading center, the magmatic activity was rather sporadic and localized. The Nuriel et al. (2009) paper that Lanzafame refers to actually advocates the idea that Troodos was a core-complex. That is, the mantle rocks were directly exposed to seawater due to faulting, which both cooled them considerably and facilitated serpentinization.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Troodos ophiolite is indeed a supra-subduction zone ophiolite. And it is reasonable to think that arc volcanism occurred somewhere, but the record is absent from the Troodos ophiolite itself. If you are interested, look up &quot;a h f robertson&quot; on Google Scholar and read some of his newer work. The article you cited is from the 70s and much research has been conducted since then.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2014-11-08T11:47:01.803" LastActivityDate="2014-11-08T11:47:01.803" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2591" PostTypeId="2" ParentId="16" CreationDate="2014-10-07T09:38:18.293" Score="7" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Ocean_acoustic_tomography&quot;&gt;Ocean acoustic tomography&lt;/a&gt; is another method that can be used to measure temperature of large bodies of water, based on the speed of sound in water. &#xA;Repeated measurements would therefore be able to show changes in ocean temperature. From the Wikipedia page:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A 1 °C change in temperature corresponds to about 4 m/s change in&#xA;  sound speed. An oceanographic experiment employing tomography&#xA;  typically uses several source-receiver pairs in a moored array that&#xA;  measures an area of ocean&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This type of experiment would make use of a &lt;a href=&quot;http://en.wikipedia.org/wiki/SOFAR_channel&quot;&gt;SOFAR channel&lt;/a&gt;, which acts as a waveguide for acoustic waves, allowing energy from a single source to travel large distances. &lt;/p&gt;&#xA;" OwnerUserId="777" LastActivityDate="2014-10-07T09:38:18.293" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2592" PostTypeId="1" CreationDate="2014-10-07T14:29:06.737" Score="13" ViewCount="414" Body="&lt;p&gt;There's a bunch of armed conflicts going on right now. What are the lower boundaries on accuracy of triangulating and timing man-made events from the &lt;a href=&quot;http://service.iris.edu/irisws/&quot;&gt;IRIS&lt;/a&gt; datasets (accessible, for instance, with the &lt;a href=&quot;http://docs.obspy.org/index.html&quot;&gt;ObsPy&lt;/a&gt; package)?&lt;/p&gt;&#xA;" OwnerUserId="269" LastEditorUserId="32" LastEditDate="2014-10-08T01:27:05.503" LastActivityDate="2020-11-15T17:42:55.740" Title="How accurately can explosions be triangulated from the IRIS seismogram data?" Tags="|geophysics|seismology|microseism|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2593" PostTypeId="2" ParentId="2592" CreationDate="2014-10-07T17:49:37.693" Score="10" Body="&lt;p&gt;David Salzberg and Margret Marshall &lt;a href=&quot;http://www.ldeo.columbia.edu/res/pi/Monitoring/Doc/Srr_2007/PAPERS/02-12.PDF&quot; rel=&quot;noreferrer&quot;&gt;suggest&lt;/a&gt; that using green receiver functions (which might make more sense given how we determine the difference between explosions and earthquakes) can locate a detonation in North Korea with up to 0.5 km accuracy. I am assuming that IRIS data sets carry enough information to make receiver functions, as I think triangulation may require a much larger event than a single nuclear warhead (not sure about this point) to be very accurate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a little background on how we determine if an event is a explosion or an earthquake (I know this isn't part of the question, but still useful for others) we look at &quot;beachball&quot; diagrams(from csegrecorder.com): &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/YTL4l.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, the &quot;beachball&quot; diagrams are visual representations of the three linearly independent stress vectors or moment tensors. I may be getting these colors reversed (so someone check on it) but &quot;white&quot; means dilation and &quot;black&quot; means compression. A fault rupture will have some compression and some dilation, meaning some &quot;white&quot; and some &quot;black&quot;, but an explosion will appear to be fully compressed because an explosion pushes on every direction. Think about a slinky: when you push on it, there is compression, and when you pull on it dilates. So an Implosion, that pulls everything towards one point, would be extensional, and thus be fully &quot;white&quot;.  &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-10-07T17:49:37.693" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2594" PostTypeId="2" ParentId="551" CreationDate="2014-10-08T18:01:58.850" Score="5" Body="&lt;p&gt;The answer to the main question is that we are capable of forecasting salinity 100 years into the future. The more relevant question might be how well are we currently forecasting salinity. First, lets look at what we know about how salinity is currently changing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Global salinity is the result of the balance between surface freshwater flux (evaporation minus precipitation), terrestrial runoff and mixing and advective processes in the ocean. The changes in salinity are intrinsically connected to alterations in the global hydrological cycle and are expected to be a consequence of climate change (&lt;a href=&quot;http://dx.doi.org/10.1175/JCLI3990.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Held and Soden, 2006&lt;/a&gt;). A general change has been identified with surface subtropical areas becoming saltier and high-latitude regions becoming fresher (&lt;a href=&quot;http://dx.doi.org/10.1029/2001JC000964&quot; rel=&quot;nofollow noreferrer&quot;&gt;Antonov et al., 2002&lt;/a&gt;; &lt;a href=&quot;http://dx.doi.org/10.1029/2004GL021791&quot; rel=&quot;nofollow noreferrer&quot;&gt;Boyer et al., 2005&lt;/a&gt;). &lt;a href=&quot;http://dx.doi.org/10.1175/2010JCLI3377.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Durack and Wijffels (2010)&lt;/a&gt; found salinity increases in regions dominated by evaporation while freshening occurred in precipitation-dominated regions. They suggested the change was a consequence of an intensification of the global hydrological cycle. These results are the basis for the conclusions in the &lt;a href=&quot;http://www.climatechange2013.org/images/report/WG1AR5_ALL_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC 2013 report&lt;/a&gt; (&lt;a href=&quot;http://www.greenfacts.org/en/climate-change-ar5-science-basis/figtableboxes/figure-tfe1.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;TFE.1 Figure 1&lt;/a&gt;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/t66rn.gif&quot; alt=&quot;IPCC TFE.1, Figure 1 - Changes in sea surface salinity are related to the atmospheric patterns of evaporation minus precipitation (E – P) and trends in total precipitable water&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://cmip-pcmdi.llnl.gov/cmip5/&quot; rel=&quot;nofollow noreferrer&quot;&gt;global climate models&lt;/a&gt; that are used to evaluate future climate scenarios are calibrated to reproduce the past ocean and atmospheric conditions, which includes trying to match the described salinity trend. They likely constitute the best source of future global salinity estimates. Their ocean salinity forecast is based on the estimation of the global hydrological cycle evolution, especially evaporation, precipitation, river discharge and ocean mixing. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regard to the quality of the salinity estimates, there is probably a large uncertainty associated with those fields. There is going to be substantial improvement in the quality of the salinity forecast because of the recent availability of better global salinity products. The remote data obtained from satellites (&lt;a href=&quot;https://earth.esa.int/web/guest/missions/esa-operational-eo-missions/smos&quot; rel=&quot;nofollow noreferrer&quot;&gt;SMOS&lt;/a&gt; and &lt;a href=&quot;http://aquarius.nasa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Aquarius&lt;/a&gt;) have been providing a much better global view of salinity changes. Also, the ARGO profilers are expanding our understanding of the ocean interior.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of evaluating uncertainty, I like the approach of &lt;a href=&quot;http://dx.doi.org/10.1029/2006GL026488&quot; rel=&quot;nofollow noreferrer&quot;&gt;Meier et al., 2006&lt;/a&gt; looking at multi-model ensemble estimates. They combined down-scaled regional models with global simulations under several scenarios and provided several metrics for salinity uncertainties. The relationship between forecast errors and forecast horizons is quite complex and in fact represents an entire field of study. There is a lot of information in the &lt;a href=&quot;http://www.climatechange2013.org/images/report/WG1AR5_ALL_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC 2013 report&lt;/a&gt; dealing with prediction quality, ensemble generation and size, and forecast quality assessment (for instance Chapter 11).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ed3BT.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ed3BT.jpg&quot; alt=&quot;salinity trend&quot;&gt;&lt;/a&gt; Source: &lt;a href=&quot;http://www.mdpi.com/2077-1312/5/4/57/htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Aretxabaleta et al. (2017)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using a little bit of self-promotion, I can also say that estimating what the current salinity trend from observations is a tough problem. In this recently  published &lt;a href=&quot;http://www.mdpi.com/2077-1312/5/4/57/htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;article&lt;/a&gt;, we show that the changes in trend are spatially complex and changing in time. We argue that, as mentioned before, the changes in salinity field give a good representation of the long-term changes in the global hydrological cycle.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2017-11-30T16:53:34.720" LastActivityDate="2017-11-30T16:53:34.720" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2595" PostTypeId="2" ParentId="2490" CreationDate="2014-10-08T20:40:01.383" Score="9" Body="&lt;p&gt;On the summer solstice, we receive more heat from the Sun than on any other day. The next day, we receive less heat from the Sun, but we still receive more heat than we lose. Thus, the temperature increases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At some point (roughly August 2nd, &quot;Midsummer's Day&quot;), we receive as much heat as we lose. That represents the maximum temperature. After that, we lose more heat than we receive and it gets colder.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mathematically, the summer solstice represents the maximum of the &lt;em&gt;derivative&lt;/em&gt; of temperature, not the maximum temperature itself.&lt;/p&gt;&#xA;" OwnerDisplayName="user967" LastActivityDate="2014-10-08T20:40:01.383" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2596" PostTypeId="1" AcceptedAnswerId="2853" CreationDate="2014-10-08T20:43:10.360" Score="10" ViewCount="1119" Body="&lt;p&gt;According to the &lt;a href=&quot;http://www.marianatrench.com/mariana_trench-oceanography.htm&quot; rel=&quot;noreferrer&quot;&gt;Mariana Trench Oceanography page&lt;/a&gt; is at a maximum depth of&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;is 11,033 meters (36,201 feet)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The 'Challenger Deep' being the name of the deepest point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand that it is a subduction trench, but my question is, &lt;strong&gt;what geological mechanism result in the great depth of the Mariana Trench over other trenches?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="725" LastEditDate="2014-10-09T07:13:47.940" LastActivityDate="2019-07-14T09:27:29.750" Title="What geological mechanisms result in the great depth of the Mariana Trench?" Tags="|geophysics|geodynamics|subduction|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2597" PostTypeId="1" AcceptedAnswerId="2619" CreationDate="2014-10-08T20:49:48.517" Score="9" ViewCount="318" Body="&lt;p&gt;As is well known, 2D simulations of turbulent flows in the ocean follow an inverse energy cascade, as opposed to a forward energy cascade observed in fully 3D flows. Because in 2D fluid filamentation is enhanced leading to strong density gradients that eventually become grid scale (where most of the mixing is owed to numerical mixing), the dissipation is underpredicted while mixing is overpredicted. As such, is there any value to running a 2D simulation with resolutions that attempt to resolve turbulence?&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="595" LastEditDate="2016-07-25T13:46:50.977" LastActivityDate="2016-07-25T13:46:50.977" Title="Given the well known effects of the inverse turbulence cascade for 2D flow, does it make sense to use grid resolutions that resolve turbulence?" Tags="|ocean|turbulence|simulation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2598" PostTypeId="2" ParentId="2585" CreationDate="2014-10-08T23:55:20.677" Score="8" Body="&lt;p&gt;The first problem to tackle is &quot;what is an odor&quot;?  An odor is a chemical aerosol or gas, which are small molecules suspended in the atmosphere.  To track the odors of pizza or burning wood you would first need to identify the molecules associated with the scent.  One example is &lt;a href=&quot;http://en.wikipedia.org/wiki/Alpha-Pinene&quot; rel=&quot;nofollow&quot;&gt;α-pinene&lt;/a&gt;, which is the molecule that gives pine trees their scent.  Food cooking typically gives off other volatile organic compounds (VOCs) and the particular matter associated with it.  VOCs physically and chemically combine to form more types of aerosols and there can also be increases in ozone.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meteorology, emissions sources, and atmospheric photochemistry are combined in chemical transport models (CTMs) so that the air quality can be predicted.  One example is &lt;a href=&quot;https://www2.acd.ucar.edu/wrf-chem&quot; rel=&quot;nofollow&quot;&gt;WRF-Chem&lt;/a&gt;, which is used for large regions and many sources. Another example is &lt;a href=&quot;http://www.src.com/&quot; rel=&quot;nofollow&quot;&gt;CALPUFF&lt;/a&gt;, which is better suited for near-source impacts and capturing the effects of complex terrain. The reason you want a model with chemistry is that molecules can be reactive and will change as they interact with other molecules turning them into things that no longer smell like pizza or wood burning.  The reason you need a meteorological model is so that pollutants will be advected with the wind and interact with the moisture budget, solar radiation, terrain, etc.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For large-scale plumes you can simulate your molecules as being emitted at a constant rate from a point source and see how this plume evolves with time.  For smaller scale flows like a pizzeria, you may need use a model that can accommodate small scale features like buildings that will have an effect on atmospheric flows.  Lastly, you'll also need to account for other emission sources as the perceived strength of the smell is also going to depend on what else you are smelling (e.g. car exhaust) and these other aerosols may be reactive or combined with the odors you are interested in tracking.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once you have done this you will have a time varying plume of &quot;smell&quot; as output from your model.  This will likely be output as a number concentration of aerosol molecules per unit volume per grid box.  To turn this into &quot;odor strength&quot; is probably a harder problem and one I am not familiar with.  As a first order approximation though, wherever the plume is located, so is the smell; and the higher the concentration of molecules, the stronger the odor.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="543" LastEditDate="2014-10-18T08:06:33.510" LastActivityDate="2014-10-18T08:06:33.510" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2599" PostTypeId="1" AcceptedAnswerId="2600" CreationDate="2014-10-09T00:43:14.883" Score="18" ViewCount="9969" Body="&lt;p&gt;While typically waves are said to &quot;feel&quot; the bottom when the depth of the water is less than half the wavelength, what does it mean for the waves to &quot;feel&quot;? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, why does this happen at the depth of half the wavelength?&lt;/p&gt;&#xA;" OwnerUserId="968" LastEditorUserId="192" LastEditDate="2014-10-09T03:20:22.297" LastActivityDate="2014-10-10T01:36:22.513" Title="What does it mean for waves to &quot;feel&quot; the bottom?" Tags="|waves|water|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2600" PostTypeId="2" ParentId="2599" CreationDate="2014-10-09T03:16:28.703" Score="20" Body="&lt;p&gt;In water wave physics, when we say that the wave &quot;feels&quot; the bottom, we mean that the water depth affects the properties of the wave. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The dispersion relationship for water waves is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\omega^2 = gk \tanh{(kd)}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\omega$ is the wave frequency, $k$ is the wavenumber, $d$ is the mean water depth, and $g$ is gravitational acceleration. We distinguish &quot;shallow&quot; and &quot;deep&quot; water waves by the value of $kd$, which includes both the wavenumber and the water depth:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Shallow water waves when $kd &amp;lt; 0.3$;&lt;/li&gt;&#xA;&lt;li&gt;Intermediate water waves when $0.3 &amp;lt; kd &amp;lt; 3$;&lt;/li&gt;&#xA;&lt;li&gt;Deep water waves when $kd &amp;gt; 3$.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Thus, a long swell wave may act as a shallow water wave in depths of 10 m, but also a very short wave may act as a deep water wave in depths of 1 m.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How are these limits for $kd$ obtained? The tangent hyperbolic function has some convenient properties for the limiting values of its argument:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/U42Q2.png&quot; alt=&quot;tanh(kd)&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For deep water waves, $kd$ is very large, so $\tanh{(kd)} \rightarrow 1$. The dispersion relationship then reduces to:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\omega^2 = gk&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Phase and group speeds are then:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;C_p = \dfrac{\omega}{k} = \sqrt{\dfrac{g}{k}}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;C_g = \dfrac{\partial \omega}{\partial k} = \dfrac{1}{2}\sqrt{\dfrac{g}{k}}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Notice that $C_p$ and $C_g$ are not a function of water depth, thus it is said that deep water waves don't &quot;feel&quot; the bottom.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, for shallow water waves, $kd$ is small (approximately 0.3 or less), and $\tanh{(kd)} \rightarrow kd$. The dispersion relationship is now:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\omega^2 = gk^2d&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and phase and group speeds are functions of water depth:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;C_p = \dfrac{\omega}{k} = \sqrt{gd}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;C_g = \dfrac{\partial \omega}{\partial k} = \sqrt{gd}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, why is it said that the waves &quot;feel&quot; the bottom at the water depth of half wavelength?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;kd = k  \dfrac{\lambda}{2} = k \dfrac{2\pi}{2k} = \pi&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and this is approximately the value below which the regime transitions from deep water to intermediate water, i.e. $\tanh{(kd)} \approx 1$ does not hold anymore. &lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2014-10-10T01:36:22.513" LastActivityDate="2014-10-10T01:36:22.513" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2601" PostTypeId="2" ParentId="2599" CreationDate="2014-10-09T03:21:38.877" Score="18" Body="&lt;p&gt;Feel the bottom refers to the fact that the wave-induced velocity field extends all the way from the top of the water column to the bottom of the water column. When the wave &quot;feels the bottom&quot; it means that there is some interaction with the bottom boundary. A very thin boundary layer develops at the bottom where vorticity is generated due to the velocity field interacting with the bed roughness. The vorticity can diffuse up into the interior of the fluid and is responsible for turbulent activity inside the boundary layer. Due to the persistent nature of waves, their action is thought to play an important role in the redistribution of particulate matter in the nearshore, such as nutrients, larvae, sediment and even contaminants.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The value of 1/2 depth is somewhat arbitrary but provides a good estimate based on theory (see IRO-bot's answer). This picture exemplifies it pretty well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/LUKMQ.jpg&quot; alt=&quot;The shape of the orbit&quot;&gt;&#xA;&lt;a href=&quot;http://science.kennesaw.edu/~jdirnber/oceanography/LecuturesOceanogr/LecWaves/1006.jpg&quot; rel=&quot;noreferrer&quot;&gt;http://science.kennesaw.edu/~jdirnber/oceanography/LecuturesOceanogr/LecWaves/1006.jpg&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2014-10-09T06:46:37.690" LastActivityDate="2014-10-09T06:46:37.690" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2602" PostTypeId="1" AcceptedAnswerId="2607" CreationDate="2014-10-09T07:58:24.657" Score="14" ViewCount="1806" Body="&lt;p&gt;New Zealand is a very active seismic and volcanic region of the Pacific Ring of Fire, on the boundary of the Australian and Pacific Plates; however, there is a difference between the 2 islands: volcanoes and earthquakes on the North Island and earthquakes only on the South Island (see maps below):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Location of New Zealand volcanoes&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/vGL6p.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://en.wikipedia.org/wiki/Ring_of_Fire&quot; rel=&quot;noreferrer&quot;&gt;Image source&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;New Zealand Earthquake Map&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Fjrt3.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://info.geonet.org.nz/display/geonet/About+GeoNet&quot; rel=&quot;noreferrer&quot;&gt;Image Source&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What are the tectonic features that account for the difference between the North and South Islands?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Additionally, how will this boundary develop in the future (geologically speaking)?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-10-13T01:13:03.300" Title="What tectonic mechanisms cause the North and South Islands of New Zealand to be so geologically different?" Tags="|earthquakes|plate-tectonics|volcanoes|tectonics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2603" PostTypeId="2" ParentId="2490" CreationDate="2014-10-09T13:00:24.110" Score="25" Body="&lt;p&gt;There are three main ways to reckon &lt;a href=&quot;http://en.wikipedia.org/wiki/Season&quot; rel=&quot;nofollow noreferrer&quot;&gt;seasons&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Solar.&lt;/strong&gt; The 3 months with the greatest insolation are designated summer, so the solstices and equinoxes fall in the middle of the season. In the Celtic calendar, summer started on 1 May; in the traditional Chinese calendar it is &lt;a href=&quot;https://en.wikipedia.org/wiki/Lixia&quot; rel=&quot;nofollow noreferrer&quot;&gt;5-7 May&lt;/a&gt;. The cultural 'Midsummer' and 'Midwinter' festivals reflect this.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Astronomical.&lt;/strong&gt; The solstices and equinoxes are the starts of the seasons, with summer starting on about 21 June (&lt;a href=&quot;http://en.wikipedia.org/wiki/Solstice&quot; rel=&quot;nofollow noreferrer&quot;&gt;it varies&lt;/a&gt;). Its use dates back at least to the Romans, and it's used in most western cultures today (apparently not in Russia, Australia, or New Zealand).&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Meteorological.&lt;/strong&gt; This is what professional meteorologists use (e.g. &lt;a href=&quot;http://www.metoffice.gov.uk/climate/uk/summaries/2014/summer&quot; rel=&quot;nofollow noreferrer&quot;&gt;UK Met Office&lt;/a&gt;), and is based on the prevailing weather on land at mid-latitudes. Seasons are 3 months long and summer starts on 1 June.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I've tried to illustrate the relationships with insolation and temperature here:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/gWNb5.png&quot; alt=&quot;Different ways to reckon seasons&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;There are some other ways too:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Ecological.&lt;/strong&gt; Scientists who study the behaviour of organisms (hibernation, blooming, etc.) adapt to the local climate, &lt;a href=&quot;http://seasons2011.blogspot.ca/2011/06/ecological-seasons.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;sometimes using 6 seasons&lt;/a&gt; in temperature zones, or only 2 in polar and tropical ones.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Agricultural.&lt;/strong&gt; This would centre around &lt;a href=&quot;http://en.wikipedia.org/wiki/Growing_season&quot; rel=&quot;nofollow noreferrer&quot;&gt;the growing season&lt;/a&gt; and therefore, in North America and Europe at least, around frost.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Cultural.&lt;/strong&gt; What people think of as 'summer', and what they do outdoors (say), generally seems to line up with local weather patterns. In my own experience, there's no need for these seasons to even be 3 month long; When I lived in Calgary, summer was July and August (hiking), and winter was December to March (skiing). &lt;a href=&quot;http://www.bom.gov.au/iwk/yawuru/index.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's another example&lt;/a&gt; of a 6-season system, and &lt;a href=&quot;http://www.bom.gov.au/iwk/maung/index.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;a 3-season system&lt;/a&gt;, from the Aboriginal people of Australia, all based on weather.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Why do systems with later season starting dates prevail today? Perhaps because at mid-latitudes, the &lt;a href=&quot;http://en.wikipedia.org/wiki/Seasonal_lag&quot; rel=&quot;nofollow noreferrer&quot;&gt;seasonal lag&lt;/a&gt; means that the start of seasonal weather is weeks later than the start of the 'insolation' period. In a system with no &lt;a href=&quot;http://en.wikipedia.org/wiki/Heat_capacity&quot; rel=&quot;nofollow noreferrer&quot;&gt;heat capacity&lt;/a&gt;, there would be no lag. In systems with high heat capacity, like the marine environment, the lag may be several months (Ibid.). Here's what the lag looks like in three mid-latitude cities:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/jOEgw.png&quot; alt=&quot;Seasonal lag. Licensed CC-BY-SA by EOEarth&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;The exact same effect happens on a &lt;a href=&quot;http://en.wikipedia.org/wiki/Diurnal_temperature_variation&quot; rel=&quot;nofollow noreferrer&quot;&gt;diurnal&lt;/a&gt; (daily) basis too — the warmest part of the day is often not midday (or 1 pm in summer). As with the seasons, there are lots of other factors too, but the principle is the same.&lt;/p&gt;&#xA;&lt;p&gt;These aren't mutually exclusive ways of looking at it — there's clearly lots of overlap here. Cultural notions of season are surely rooted in astronomy, weather, and agriculture.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="-1" LastEditDate="2021-02-26T11:44:25.833" LastActivityDate="2021-02-26T11:44:25.833" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="2604" PostTypeId="1" CreationDate="2014-10-09T15:23:40.253" Score="25" ViewCount="5146" Body="&lt;p&gt;Wind turbines work by converting some of the energy from wind to electrical energy. Is it possible to have too many turbines, leading to them removing too much energy from the wind?  I'm not an environmental scientist, but I'm guessing the energy in wind plays some vital role in the environment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what would happen if we removed too much of that energy?&lt;/p&gt;&#xA;" OwnerUserId="973" LastEditorUserId="56" LastEditDate="2014-10-22T02:14:18.267" LastActivityDate="2019-07-03T09:11:12.620" Title="Could the extraction of energy by wind turbines be harmful to the environment?" Tags="|climate-change|wind|human-influence|environmental-protection|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2605" PostTypeId="2" ParentId="2604" CreationDate="2014-10-09T18:23:25.473" Score="24" Body="&lt;p&gt;The short answer is yes, it's possible. And it can also reduce harm.&lt;/p&gt;&#xA;&lt;h3&gt;Summary of the changes&lt;/h3&gt;&#xA;&lt;p&gt;Here's a brief summary of the changes that happen when electricity is generated from a wind turbine, rather than from a fossil or nuclear plant:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;energy is taken out of the wind further upwind than it would otherwise be&lt;/li&gt;&#xA;&lt;li&gt;there is more turbulence just downwind from the wind turbine&lt;/li&gt;&#xA;&lt;li&gt;less low-grade heat is put into the environment around the fossil or nuclear plant that has been turned down, or off, because the electricity is supplied from wind now.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;hr /&gt;&#xA;&lt;h3&gt;Global impacts&lt;/h3&gt;&#xA;&lt;p&gt;As far as we can tell it's unlikely that there would be global effects at any plausible levels of global deployment (let's say, up to terawatts of mean power, but below tens of terawatts). But a single row of turbines can be enough to cause very local effects, and those could be positive or negative.&lt;/p&gt;&#xA;&lt;p&gt;There is an open discussion in the literature about what the impact of removing terawatts of wind power would be.  But it's a theoretical discussion, and not really meaningful, because it would absolutely depend on where the power was extracted.&lt;/p&gt;&#xA;&lt;h3&gt;What happens to the wind's energy?&lt;/h3&gt;&#xA;&lt;p&gt;Ultimately, pretty much all energy in the wind ends up as low-grade heat. And that's regardless of whether or not it gets there via a wind turbine or not. If not, it will eventually dissipate due to friction, where it becomes ambient low-grade heat. If it is, then it will get converted into electricity, then some energy service (e.g. lighting), and then ambient low-grade heat.&lt;/p&gt;&#xA;&lt;p&gt;So deploying lots of wind turbines just moves &lt;em&gt;where&lt;/em&gt; that energy gets taken out of the wind, but not how much.&lt;/p&gt;&#xA;&lt;p&gt;An unshrouded turbine can extract at most 16/27ths (59.3%) of the wind's kinetic energy - that's the Betz limit. In practice, it's more like 20-50%. Here's the power curve for an E82-Enercon 3MW turbine, from &lt;a href=&quot;http://www.enercon.de/p/downloads/EN_Productoverview_0710.pdf&quot; rel=&quot;noreferrer&quot;&gt;the Enercon brochure&lt;/a&gt;:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/tjSF5.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;The lighter curve, plotted against the vertical axis on the right, shows the proportion of the wind's kinetic energy that is converted to electricity. At around 9 m/s wind speeds, that proportion maxes out at about 50%. A further small (~2) percentage goes to internal conversion losses within the turbine.&lt;/p&gt;&#xA;&lt;h3&gt;What are the energy changes, and where?&lt;/h3&gt;&#xA;&lt;p&gt;The full picture is more complicated. Whether switching from fossil/nuclear to wind would change patterns of energy service demand, and energy efficiency, is an open question, so there are plenty of ripple effects. But, putting those aside to simplify things, just switching from fossil/nuclear to wind wouldn't create new sinks for the low-grade heat: lighting would carry on getting used at the same time and place as it does at the moment. What would happen is that energy would be extracted from the wind in new places: at turbines, rather than further downwind where the energy would be dissipated by friction. The other thing that would change is that there would no longer be additional sources of low-grade heat at all those fossil and nuclear power stations. Now, they're pretty intense sources of heat: nuclear or coal plants typically push out 150% - 200% as much energy as local heat, as they do electricity. So that's a significant input of heat into a local weather system, which would no longer be there when they're turned off because the electricity is being supplied from wind instead.&lt;/p&gt;&#xA;&lt;h3&gt;A quick romp through the literature&lt;/h3&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://dx.doi.org/10.1088/1748-9326/8/3/034006&quot; rel=&quot;noreferrer&quot;&gt;Smith, Barthelmie &amp;amp; Prior used In situ observations of the influence of a large onshore wind farm on near-surface temperature, turbulence intensity and wind speed profiles&lt;/a&gt;. They found that in the daytime, there was no observable change in temperatures once they were more than 2km downwind from turbines. However, there was an increase in night-time temperatures at 2.5m above ground (hence the use by farmers of wind turbines for frost prevention)&lt;/p&gt;&#xA;&lt;p&gt;On top of what I've written above, we've also got a bunch of modelling in the literature. Now, this is largely an argument between different assumptions: pick the answer you want, and tune your assumptions accordingly. However, these papers are written by people with different underlying positions, so you'll find a range of possible outcomes, and you can decide for yourself which assumptions are more or less likely.&lt;/p&gt;&#xA;&lt;p&gt;Mark Z Jacobson wrote the book on the Fundamentals of Atmospheric Modelling, and tends to build up from the micro level. &lt;a href=&quot;http://dx.doi.org/10.1038/nclimate2120&quot; rel=&quot;noreferrer&quot;&gt;A recent paper of his&lt;/a&gt; shows potential benefits of reducing the energy in hurricanes that reach the shore, and we know that the first-order impacts of that would be positive.&lt;/p&gt;&#xA;&lt;p&gt;Roy &amp;amp; Traiteur looked at &lt;a href=&quot;http://dx.doi.org/10.1073%2Fpnas.1000493107&quot; rel=&quot;noreferrer&quot;&gt;Impacts of wind farms on surface air temperatures&lt;/a&gt; and found significant very local effects, and options for mitigation.&lt;/p&gt;&#xA;&lt;p&gt;Wang &amp;amp; Prinn looked at &lt;a href=&quot;http://dx.doi.org/10.5194/acp-10-2053-2010&quot; rel=&quot;noreferrer&quot;&gt;potential long-term global impacts of multi-terawatt-scale installations&lt;/a&gt; and found that massive onshore wind turbines might cause some warming over land (though less than the coal &amp;amp; gas plants they would replace), and massive offshore wind turbines might cause some global cooling. The modelling was done by assuming the turbine interactions would behave like a generic increase in surface roughness; the other key assumption is that the loss of detail from meso-scale modelling did not significantly impact the results.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://dx.doi.org/10.1175/2007JAS2509.1&quot; rel=&quot;noreferrer&quot;&gt;Kirk-Davidoff and Keith&lt;/a&gt;, like Wang and Prinn, used coarse meso-scale modelling by adding anomalies to surface roughness coefficients. With continental-scale windfarms, they found very little change in global temperatures, but local changes could be up to 2 Kelvin.&lt;/p&gt;&#xA;&lt;p&gt;Rooijmans' Masters' thesis (Universiteit Utrecht, 2004) looked at the impact of a huge (9 000 km&lt;sup&gt;2&lt;/sup&gt;) offshore wind farm on patterns of rainfall, using a mesoscale circulation model, and found that the distribution of precipitation could change, with more rain at sea, and less onshore. That modelled windfarm would be about four times the size of the largest envisaged offshore wind farm.&lt;/p&gt;&#xA;&lt;h3&gt;Consequences and conclusions&lt;/h3&gt;&#xA;&lt;p&gt;Distributions of heat affect weather and climate. So, deploying lots of wind turbines can change local patterns of evaporation and rainfall. They can also change patterns of frost: the turbines increase the turbulence in the flow, close to the ground, reducing frosts: there are farms that deploy turbines in order to harness that frost-prevention: you can even (HT scruss) buy &lt;a href=&quot;http://www.orchard-rite.com/wind.cfm?m=92&quot; rel=&quot;noreferrer&quot;&gt;wind machines&lt;/a&gt; dedicated to producing that turbulence in no-wind conditions (these wind machines, ironically, are typically powered by fossil fuels).&lt;/p&gt;&#xA;&lt;p&gt;So that's the ultimate change: energy would be extracted from the wind further upstream than it was previously; and there's less heat put into the system from the cooling systems at fossil and nuclear power stations. These are all local weather effects, and could be beneficial, harmful, or neutral.&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-07-03T09:11:12.620" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="2606" PostTypeId="2" ParentId="2604" CreationDate="2014-10-09T20:41:01.487" Score="2" Body="&lt;p&gt;EnergyNumbers' answer is correct for the global scale however a wind mill has a different effect on wildlife which can have other long term consequences: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Noise pollution can disturb local wildlife; this in especially true when wind mills are build in water where the noise carries much further. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Wind turbines often kill birds (and a even larger number of bats), For a small number of windmills this effect is quite small but if you have a large number of wind mills the number of birds that die grows and this can cause them to perhaps even go extinct. Because birds often carry seeds and eat pests losing them could have serious consequences for your environment. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;If these two points are combined then having too many windmills could be a risk to the environment. &lt;/p&gt;&#xA;" OwnerUserId="976" LastEditorUserId="270" LastEditDate="2014-10-10T14:14:30.803" LastActivityDate="2014-10-10T14:14:30.803" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2607" PostTypeId="2" ParentId="2602" CreationDate="2014-10-10T02:44:39.657" Score="10" Body="&lt;p&gt;New Zealand sits along an oblique convergent plate boundary, where the Pacific and Australia Plates meet. The boundary between the two plates is shown in your second figure as the grey line, with the Pacific Plate to the east and the Australia Plate to the west of it. In terms of relative movement, we can think of the Australia Plate as being stationary and the Pacific Plate having a west to south-west direction of movement. The angle at which the Pacific Plate moves into the Australia plate changes along the length of New Zealand - this is what causes the differences in tectonic style and thus differences in volcanism and earthquake occurance (and motion) between North and South Islands. The angle changes from north to south due to: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;a clockwise rotation of the Pacific Plate, and &lt;/li&gt;&#xA;&lt;li&gt;Pacific and Australia plates meeting at varying angles.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;If this boundary was straight and the Pacific Plate moved orthogonal to it, then there would only be subduction, as the Pacific Plate is denser than the Australian. Conversely, if the Pacific Plate moved parallel to the Australia Plate there would be no subduction. Along the length of NZ both of these end-members (and variations in between!) are observed, as not only is the plate boundary slightly curved over the length of New Zealand, but the movement of the Pacific Plate has an component of clockwise rotation. &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0040195111002204&quot; rel=&quot;nofollow&quot;&gt;Lamb (2011)&lt;/a&gt; shows that there has been 70-90 degrees of clockwise rotation of the boundary/margin over the last 20 million years, and it is still occuring today. The differing angles of intersection between Pacific and Australia plate along the length of NZ cause differences in tectonic style, which give rise to differences in volcanism and earthquake occurance and motion. &lt;a href=&quot;http://en.wikipedia.org/wiki/Geology_of_New_Zealand#Astride_a_plate_boundary&quot; rel=&quot;nofollow&quot;&gt;The figure in this section of the Geology of New Zealand Wikipedia page&lt;/a&gt; shows the variations of displacement vector (direction and magnitude of motion) along the length of New Zealand. Notice how the vectors are more orthogonal to the plate boundary in the North Island and become more acute in the South Island. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Subduction occurs in the North Island because the Pacific Plate moves rougly orthogonal to the boundary with the Australian Plate and is denser than than the crust around New Zealand; the Pacific Plate is composed mainly of basalt, while New Zealand is an amalgamation of different sedimentary and volcanic rocks. As the Pacific Plate is subducted is bends and breaks, causing earthquakes. It also melts, causing volcanoes. Notice how the depth of earthquakes in the North Island gets deeper to the west - this is due to the continued westward movement of the Pacific Plate even as it subducts under the Australia Plate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Over most of the South Island the Pacific Plate moves roughly parallel to the boundary of the Australia Plate. The Southern Alps are caused by slight obduction (up and over movement) of the Pacific Plate over the Australia Plate.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To the south of the South Island the polarity of subduction is reversed, with the Australian Plate being subducted beneath the Pacific Plate  (e.g. &lt;a href=&quot;ftp://ftp.earth.ox.ac.uk/pub/karenr/thesis.pdf&quot; rel=&quot;nofollow&quot;&gt;Randall, 2007&lt;/a&gt;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This post is a huge simplification of the tectonics of NZ. The geology of this continental fragment is very complicated, but also very interesting! Have a look at &lt;a href=&quot;http://www.youtube.com/watch?v=E6Nyr78Mqyg&quot; rel=&quot;nofollow&quot;&gt;this video&lt;/a&gt; to see how the plate boundary has changed over time. &lt;/p&gt;&#xA;" OwnerUserId="777" LastEditorUserId="777" LastEditDate="2014-10-13T01:13:03.300" LastActivityDate="2014-10-13T01:13:03.300" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2608" PostTypeId="2" ParentId="2604" CreationDate="2014-10-10T07:11:49.990" Score="7" Body="&lt;p&gt;&lt;a href=&quot;http://www.nature.com/nclimate/journal/v4/n3/full/nclimate2120.html&quot;&gt;Taming hurricanes with arrays of offshore wind turbines&lt;/a&gt; Nature Climate Change 4, 195–200 (2014)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It finds that large turbine arrays (300+ GW installed capacity) may diminish peak near-surface hurricane wind speeds by 25–41 m s−1 (56–92 mph) and storm surge by 6–79%.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In the case of offshore turbine arrays in particular locations there is potential benefit of significantly reducing the destructive effects of hurricanes on coastal eco-systems.&lt;/p&gt;&#xA;" OwnerUserId="979" LastActivityDate="2014-10-10T07:11:49.990" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2609" PostTypeId="2" ParentId="416" CreationDate="2014-10-10T18:46:32.050" Score="3" Body="&lt;p&gt;There is still some uncertainty, but some recent research is detailed below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In research reported in the article &lt;a href=&quot;http://pmc.ucsc.edu/~apaytan/publications/2012_Articles/Griffith%202012.pdf&quot; rel=&quot;nofollow&quot;&gt;Barite in the ocean – occurrence, geochemistry and&#xA;palaeoceanographic applications&lt;/a&gt; (Griffith and Paytan, 2012), recent observations and research found that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Using the non-carbonate Sr content in&#xA;  suspended particles to track the presence of&#xA;  acantharia, van Beek et al. (2007) suggest that&#xA;  acantharian dissolution does contribute signifi-&#xA;  cantly to barite formation in the upper 500 m of&#xA;  the water column&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, a lack of a definitive correlation between the barite concentrations and acantharian distributions suggest that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;these organisms are&#xA;  not required for the formation of barite in the&#xA;  water column (Bertram &amp;amp; Cowen, 1997)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and that further observations&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;provided direct evidence to support&#xA;  the water column micro-environment mechanism&#xA;  of marine barite formation and to verify that&#xA;  barite can form in the absence of acantharia.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The concentration of strontium in barite is a record of the Sr isotopic composition of the formation fluids, which according to the article has its source from sea water, sediments (both marine and terrigenous) and hydrothermal fluids. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is this last point, particularly about the Sr concentrations in sea-water, which according to the article &lt;a href=&quot;http://www.aslo.org/lo/toc/vol_55/issue_2/0604.pdf&quot; rel=&quot;nofollow&quot;&gt;Sedimentation of acantharian cysts in the Iceland Basin: Strontium as a ballast for deep&#xA;ocean particle flux, and implications for acantharian reproductive strategies&lt;/a&gt; (Martin et al. 2010) state can fluctuate by several percent  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;By precipitating celestite, Acantharia can reduce surface&#xA;  seawater strontium (Sr) concentrations by up to 5%&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Experimentally the authors found that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Sr fluxes we report are&#xA;  too high to be attributed to nonacantharian sources.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-10-10T18:46:32.050" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2610" PostTypeId="2" ParentId="2484" CreationDate="2014-10-10T21:34:33.900" Score="3" Body="&lt;p&gt;A general statement about the placement of seismometers around a volcano is provided on the USGS page &lt;a href=&quot;http://volcanoes.usgs.gov/activity/methods/seismic/&quot; rel=&quot;nofollow&quot;&gt;Monitoring Volcano Seismicity&lt;/a&gt;, that a significant factor in their placement is to detect 'microquakes':&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Seismic networks are made up of several instruments. Having enough of the right instruments located in strategic places is especially important for detecting earthquakes smaller than magnitude 1 or 2; sometimes, these tiny earthquakes represent the only indication that a volcano is becoming restless.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They state that detection of these microquakes requires seismometers to be placed near the crater.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Placing them in rings around the volcano (in accessible and safe areas) allows scientists to accurately model the seismic changes, hence changes in the nature of the underlying magma chamber and the movement of magma and fluids.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An example is presented in the presentation &lt;a href=&quot;http://www.eecs.harvard.edu/~mdw/proj/volcano/reventador-usenix.pdf&quot; rel=&quot;nofollow&quot;&gt;Deploying a Sensor Network&#xA;on an Active Volcano&lt;/a&gt; using Tungurahua and Reventador volcanoes in Ecuador, seismometers are typically separated by at least 100m, across and up-and-down the volcano - this allows the identification of where the movement is occurring (whether the event is from the cone or deep within the volcano).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Practically speaking, according to the article &lt;a href=&quot;http://www.nat-hazards-earth-syst-sci-discuss.net/1/4305/2013/nhessd-1-4305-2013-print.pdf&quot; rel=&quot;nofollow&quot;&gt;A wireless sensor network for monitoring&#xA;volcanic tremors&lt;/a&gt; (Pereira et al. 2013), the spacing ought to be&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The sensors must cover a region where the entire&#xA;  phenomena can be evaluated. Therefore, the coverage area must comprise, at least,&#xA;  one wavelength of distance between the two sensors farther away from each other.&#xA;  Since both the direction and speed of the tremor wave need to be estimated, at least,&#xA;  two sensors in each one of the cardinal points are required.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The authors emphasise the need for the networks to be flexible in terms of their location.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The authors also state that cost is a major factor - not only of the instruments, but of personnel to monitor and analyse the data.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-10-10T21:34:33.900" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2611" PostTypeId="2" ParentId="2423" CreationDate="2014-10-11T00:21:21.123" Score="7" Body="&lt;p&gt;I don't have personal experience with this situation, but reading around suggests it depends what kind of mixing you are talking about, for example whether it is vertical or horizontal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looking around for recent examples, I see Chao et al. (2007) had a value of 4.0&amp;nbsp;m&lt;sup&gt;2&lt;/sup&gt;/s for horizontal diffusivity. This larger value would give you a smaller Péclet number of 150. Your use of wavelength for the characteristic length suggests you might be more interested in that dimension?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Chao et al. used ~10&lt;sup&gt;–5&lt;/sup&gt;&amp;nbsp;m&lt;sup&gt;2&lt;/sup&gt;/s for vertical diffusivity, and I find &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0485(1997)027%3C1181%3ASRAMBR%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bogucki et al.&lt;/a&gt; and &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/2011JPO4578.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lien et al.&lt;/a&gt; using ~10&lt;sup&gt;–2&lt;/sup&gt;&amp;nbsp;m&lt;sup&gt;2&lt;/sup&gt;/s and ~10&lt;sup&gt;–2&lt;/sup&gt;&amp;nbsp;m&lt;sup&gt;2&lt;/sup&gt;/s respectively. Those are not too distant from your number, and it looks like Moum et al. are talking about vertical mixing. However in this case I am not sure you want to use horizontal length and velocity; you might consider asking about this in &lt;a href=&quot;https://physics.stackexchange.com/questions/tagged/fluid-dynamics&quot;&gt;Physics.SE&lt;/a&gt;, using the &lt;em&gt;fluid-dynamics&lt;/em&gt; tag.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In any case, as we hone our intuition about such things, I like this quote from Durran (1999):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The &lt;a href=&quot;http://en.wikipedia.org/wiki/P%C3%A9clet_number&quot; rel=&quot;nofollow noreferrer&quot;&gt;Péclet number&lt;/a&gt; is completely analogous to the more familiar&#xA;  &lt;a href=&quot;http://en.wikipedia.org/wiki/Reynolds_number&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reynolds number&lt;/a&gt;, which is the ratio of momentum advection to momentum&#xA;  diffusion. The difference between the Péclet and Reynolds numbers is&#xA;  due to the difference in the diffusivities of heat [or mass] and&#xA;  momentum. [My addition]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I like this because it suggests that some of the same intuition we have about &lt;em&gt;Re&lt;/em&gt; may apply to &lt;em&gt;Pe&lt;/em&gt; too, especially the fact that it can vary by several orders of magnitude (&lt;a href=&quot;http://www.hitech-projects.com/euprojects/artic/index/Low%20Reynolds%20number%20flows.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;from here&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Whale swimming at 10 m/s, &lt;em&gt;Re&lt;/em&gt; = 3&amp;nbsp;×&amp;nbsp;10&lt;sup&gt;8&lt;/sup&gt;&lt;/li&gt;&#xA;&lt;li&gt;Duck flying at 20 m/s, &lt;em&gt;Re&lt;/em&gt; = 3&amp;nbsp;×&amp;nbsp;10&lt;sup&gt;5&lt;/sup&gt;&lt;/li&gt;&#xA;&lt;li&gt;Copepod swimming at 0.2 m/s, &lt;em&gt;Re&lt;/em&gt; = 3&amp;nbsp;×&amp;nbsp;10&lt;sup&gt;2&lt;/sup&gt;&lt;/li&gt;&#xA;&lt;li&gt;Larva swimming at 0.001 m/s, &lt;em&gt;Re&lt;/em&gt; = 3&amp;nbsp;×&amp;nbsp;10&lt;sup&gt;–1&lt;/sup&gt;&lt;/li&gt;&#xA;&lt;li&gt;Bacterium swimming at 0.00001 m/s, &lt;em&gt;Re&lt;/em&gt; = 1&amp;nbsp;×&amp;nbsp;10&lt;sup&gt;–5&lt;/sup&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;br&gt;&#xA;Shenn-Yu Chao et al., 2007, Assessing the West Ridge of Luzon Strait as an Internal&#xA;Wave Mediator, &lt;em&gt;Journal of Oceanography&lt;/em&gt;, Vol. 63, pp. 897 to 911, 2007. &lt;a href=&quot;http://www7320.nrlssc.navy.mil/NLIWI_WWW/images/JO63-6-02.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Available online.&lt;/a&gt;&lt;br&gt;&#xA;Durran, D, 1999, &lt;em&gt;Numerical Methods for Wave Equations in Geophysical Fluid Dynamics.&lt;/em&gt; Springer. &lt;a href=&quot;http://books.google.ca/books?id=vk5GSqyPOzcC&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google Books.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="-1" LastEditDate="2017-04-13T12:40:15.470" LastActivityDate="2014-10-11T00:21:21.123" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2612" PostTypeId="2" ParentId="989" CreationDate="2014-10-11T12:08:23.713" Score="5" Body="&lt;p&gt;According to the paper &lt;a href=&quot;http://jupiter.ethz.ch/~akhan/amir/Publications_files/tecto_moon13.pdf&quot; rel=&quot;noreferrer&quot;&gt;The lunar moho and the internal structure of the Moon: A geophysical perspective&lt;/a&gt; (Khan et al. 2013), suggest 2 causes for the less frequent, yet more energetic shallow moonquakes:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Similar tectonic movements to intraplate quakes on Earth, also mentioned in the NASA paper &lt;a href=&quot;http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20130013896.pdf&quot; rel=&quot;noreferrer&quot;&gt;Interior of the Moon &lt;/a&gt; (Weber, 2013), but this seems unlikely due to the lack of plate tectonics on the Moon, but in an earlier paper, cited by Khan et al. (2013), &lt;a href=&quot;http://adsabs.harvard.edu/abs/1980LPSC...11.1847N&quot; rel=&quot;noreferrer&quot;&gt;Shallow moonquakes - How they compare with earthquakes&lt;/a&gt; (Nakamura, 1980), suggests that slippage in near surface fracture zones are a possible mechanism.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;An alternative explanation suggested is the&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;possibility that shallow moonquakes may&#xA;  instead be triggered by objects emanating from outside the solar system,&#xA;  such as nuggets of strange quark matter.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, as there have only been 28 recorded since we've been to the moon, it is hard to exactly say.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-10-11T12:08:23.713" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2613" PostTypeId="2" ParentId="2478" CreationDate="2014-10-11T13:59:10.460" Score="4" Body="&lt;p&gt;A reason found experimentally is that the pressure and temperature conditions at the mantle-core boundary result in the reduction of aluminium oxides.  According to the Nature article &lt;a href=&quot;http://www.nature.com/nature/journal/v412/n6846/full/412527a0.html&quot; rel=&quot;nofollow&quot;&gt;Chemical interaction of $\ce{Fe}$ and $\ce{Al2O3}$ as a source of heterogeneity at the Earth's core–mantle boundary&lt;/a&gt; (Dubrovinsky et al. 2001) through their experiments simulating the thermochemical conditions at the boundary, that one of the main factors in the core-mantle boundary region is &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;that iron is able to reduce aluminium out of oxides at core–mantle boundary conditions&lt;/strong&gt;, which could provide an additional source of light elements in the Earth's core and produce significant heterogeneity at the core–mantle boundary.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Further, from the ESRF Highlights 2001 webpage &lt;a href=&quot;http://www.esrf.eu/UsersAndScience/Publications/Highlights/2001/chemistry/CHEM4.html&quot; rel=&quot;nofollow&quot;&gt;Chemical Interaction of Iron and Corundum at High Pressure and Temperature: Implication for the Earth's Deep Interior&lt;/a&gt;, experimentally found that the following reaction, forming iron-aluminium compounds (amongst other alloys) occurred at temperatures that are believed to exist at the mantle-core boundary:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\ce{($2+3x$)Fe + $x$Al2O3 -&amp;gt; 2FeAl_{$x$} + $3x$FeO}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where $x$ varied between 0.02-0.03 to 0.25&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="87" LastEditDate="2014-12-03T07:26:35.877" LastActivityDate="2014-12-03T07:26:35.877" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2614" PostTypeId="2" ParentId="2585" CreationDate="2014-10-11T20:38:03.570" Score="6" Body="&lt;p&gt;Ofc what casey said is true, but I think the basic physics involved can be understood pretty easily by the mention of the &lt;a href=&quot;http://en.wikipedia.org/wiki/Convection%E2%80%93diffusion_equation&quot;&gt;advection-diffusion-equation&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$\partial_t c = - \vec v \cdot \vec \nabla c + \mu \Delta c$ &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;This is the easiest model possible for this process, covering transport of the chemical compound with concentration $c(\vec x, t)$ by the wind (first term) and diffusion in adjacent air parcells (second term).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The operator $\vec v \cdot \vec \nabla$ will transport anything that you put behind it, in real space. I.e. perhaps you know this from the &lt;a href=&quot;http://en.wikipedia.org/wiki/Navier%E2%80%93Stokes_equations&quot;&gt;Navier-Stokes-equation&lt;/a&gt; where the famous &quot;self-transport&quot;-term $(\vec v \cdot \vec \nabla)\vec v$ causes alot of complications.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then $\mu \Delta$ is the molecular diffusivity times the Laplace-operator which appears also in any random-walk / diffusion modell.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So this could give you the means to calculate the question you posed even by hand. Ofc the &quot;disapperaing&quot; of an odor, is just c falling below some threshhold value, where it is still noticable for human biology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One interesting thing to note here, is that in a stratified atmosphere you obviously have a preferred direction in 3D-space. This will make the diffusivity $\mu$ more efficient in the horizontal plane, than vertically. You could take this into account by splitting your Laplacian into $\mu_{vertical}\partial_{zz} + \mu_{horizontal}(\partial_{xx} + \partial_{yy})$.&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="489" LastEditDate="2014-10-11T20:53:51.280" LastActivityDate="2014-10-11T20:53:51.280" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2615" PostTypeId="2" ParentId="875" CreationDate="2014-10-11T21:11:30.903" Score="12" Body="&lt;p&gt;Well the dinosaur-killing asteroid that struck the Yucatan peninsula in the gulf of Mexico (65 million years ago!) generated a seismic shock or earthquake that went around the world and registered magnitude 13 on the Richter scale the reason for this was the object was 6 miles in diameter and its mass was equal to all the construction-materials used for every building in the entire USA.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if you have an object that size (or larger) hitting the earth at a sufficient enough velocity (40-60 000 mph) than yes Magnitude 10 quakes or larger are possible even if they're rare!&lt;/p&gt;&#xA;" OwnerUserId="990" LastActivityDate="2014-10-11T21:11:30.903" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2616" PostTypeId="1" CreationDate="2014-10-11T22:04:12.427" Score="9" ViewCount="1927" Body="&lt;p&gt;When investigating the rate of the move of the Hawaii hotspot, from information provided here on Stack Exchange Earth Science, I cannot find a determination of cause for the rate, that does not point back to plate tectonics as the reason for the rate, but I am unable to determine if there is a known cause for the rate of plate tectonics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Random?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Natural sphere dynamics and nothing else?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The angles between the milky way, the &quot;great attractor&quot;, the CMB, and earth's place between the three?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Other geological processes of which I am unaware??&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Speaking to the possibility of it being #3, as far as I can determine, the sun seems to orbit around the Milky Way with a similar periodicity as many geological functions I am aware of on Earth.  And the formation then spread of Pangea and recollection into Pangea Ultima if correctly predicted, would seem to further bolster this thought.  And the rate of orbit around the Milky Way would seem to approximate (or match) the rate of the hotspots movement, which other than &quot;driven by plate tectonics&quot; would seem to be a global mystery.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So &quot;little help over here&quot;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;ADDED Oct 12, an excerpt from an article provided by Omen.  Please ignore the part about evolutionary pressure.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The amount of radioactive material in the Core was certainly greater&#xA;  in the distant past. That greater amount proportionally created&#xA;  greater heat amounts which had to get to the Earth's surface to be&#xA;  able to be radiated away. One result of this was certainly that the&#xA;  materials of the Core and Mantle were hotter than today, and therefore&#xA;  more fluid. That situation was enhanced by the remaining presence of a&#xA;  substantial amount of heat remaining from the original formation of&#xA;  the Earth. Finally, convection cell flow rates are driven by the&#xA;  amount of heat that is present, so that also would make the Core&#xA;  convective cells and the Mantle convective cells much more active and&#xA;  much more dynamically unstable than today.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The result of all this was more heat driving convective cells in&#xA;  materials which were more fluid. This necessarily caused more rapid&#xA;  movements of those materials. This would have created substantially&#xA;  greater geomagnetic field strengths in the distant past. It would also&#xA;  have caused far more rapid lateral flow velocities in the Mantle&#xA;  convection cell tops.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Depending on the 'grip' (or static / dynamic coefficient of friction)&#xA;  between Mantle and Crust, this could enable very rapid tectonic plate&#xA;  movements in the distant past. When that caused substantial&#xA;  north-south movement in the continental plates, strong evolutionary&#xA;  pressure would suddenly exist.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;ADDED OCT 20th, 2014&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sorry for the delay, I waited a little to compose my words correctly, and to see if any alternate theories were strongly supported, to explain the 200+ million year rate of movement of the Emperor chain.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To the best of my ability to understand the answers so far, the &quot;RATE&quot; of &#xA;churn&quot; within the mantle, and resulting heaving and swirling of plate movement are derivatives of:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the amount of heat within the earth,&lt;br&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;primordial,  &lt;/li&gt;&#xA;&lt;li&gt;gravity pressure,&lt;/li&gt;&#xA;&lt;li&gt;radioactive decay,  &lt;/li&gt;&#xA;&lt;li&gt;tidal friction),&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;combined with&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the gravitational tugs of the Sun and Moon on Earth,&lt;/li&gt;&#xA;&lt;li&gt;the resulting &quot;jitter&quot; within the earth caused by the Milankovitch cycles&lt;/li&gt;&#xA;&lt;li&gt;and the physical dynamics, properties and characteristics of&#xA;&lt;ul&gt;&#xA;&lt;li&gt;heat generation rates,&lt;/li&gt;&#xA;&lt;li&gt;and transfer rates through varied mediums,&lt;/li&gt;&#xA;&lt;li&gt;sphere dynamics,&lt;/li&gt;&#xA;&lt;li&gt;the patterns within the movements caused by existing physical geographical patterns&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;plus the random interaction between the Earth and various celestial bodies that have happened into our path over time, creating such geological features as the gulf of Mexico, the pool of nickel under Sudbury, etc.&#xA;.  &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;And therefor the shape of mountains and valleys, continent and ice cap are existential in nature.  Random compared to other regards, such as other universal interaction to the Milky Way, or the shape and position and relative density of the various parts of the superclusters Laniakea and Perseus.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is I believe accepted as the depth to which the situation has been considered?  Or it has been considered further with less information and been decided non-consequential, perhaps (ie declining influence of gravitational force over distance)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some of the things within this frame-work of cumulative understandings, that I see as &quot;unknown&quot;, &quot;not clearly known&quot;, &quot;potential factors&quot;, &quot;assumptions&quot;, &quot;theories&quot; that are in contention&quot;, or &quot;flat out Scooby Doo mysteries&quot; are many and of significant value in consideration:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the nature of the insides of an atom (now believed filled with Quanta energy field, the ratio of this energy to the mass energy of the sub components of the atom are massive), &lt;/li&gt;&#xA;&lt;li&gt;the nature of the insides of space (now believed &quot;filled&quot; with Dark Matter and Dark Energy equalling 95-96 percent of existence, squishing the 4% we see, know, and understand, into a pretty small corner.&lt;/li&gt;&#xA;&lt;li&gt;the nature of the &quot;shape&quot; of gravity, sought by IBEX, being re-sought by the Planck mission&lt;/li&gt;&#xA;&lt;li&gt;the nature of the &quot;shape&quot; of the Universe, (we have only in the past decade &quot;perceived documented and published&quot; details of the super-clusters existence.  It is built on current understanding which include above noted lack of understanding.&lt;/li&gt;&#xA;&lt;li&gt;the nature of the origins of the Universe (the existence of the superclusters pretty much rule out the &quot;viability of the truth of the Big Bang Theory (R.I.P.)&lt;/li&gt;&#xA;&lt;li&gt;the cause of the Milankovitch cycles ranges, parameters, timing, (causes I think)??&lt;/li&gt;&#xA;&lt;li&gt;the rate of disassembly of Pangea and recreation into the predicted PangeaUltima.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;And so it is recognition of these conditions combined that begged me to ask the question...Is it known what determines the RATE with which plate tectonics occur?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The true underlying cause of the timing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And as far as I can tell the best answer is circumstantial existence combined with the Sun and the moon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Creating &quot;It Is, What It Is.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll post this as an answer but I hope it get's down voted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And some latitude to explore hypothetically will be granted.  :-)&lt;/p&gt;&#xA;" OwnerUserId="809" LastEditorUserId="809" LastEditDate="2014-10-20T19:35:04.107" LastActivityDate="2014-10-20T19:44:15.640" Title="Is it known what determines the rate with which plate tectonics occur?" Tags="|geophysics|tectonics|" AnswerCount="3" CommentCount="6" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2617" PostTypeId="2" ParentId="2616" CreationDate="2014-10-11T23:59:32.130" Score="7" Body="&lt;p&gt;We have a reasonably good idea of what mechanisms cause varying rates of plate tectonic movement.  First though, the overall mechanism is postulated and generally accepted as being due to &lt;strong&gt;mantle convection&lt;/strong&gt;, as summarised in the diagram below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/JUsBN.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image source: &lt;a href=&quot;http://volcanoes.usgs.gov/about/edu/dynamicplanet/nutshell.php&quot; rel=&quot;noreferrer&quot;&gt;USGS&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Essentially, the mantle plume is heated by deeper processes, so it partly melts and rises towards the surface and drags the crust, cooling at the same time, and the cooler more dense material drops (A full description is on the link).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, in answer to your question about the &lt;em&gt;rate&lt;/em&gt; of tectonic movement, the factors that cause different rates, suggested on the webpage &lt;a href=&quot;http://mb-soft.com/public/tecto3.html&quot; rel=&quot;noreferrer&quot;&gt;The Mechanism Causing Plate Tectonic Movements&lt;/a&gt; friction between the crust and mantle, and friction at collision zones play a major role, as illustrated below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/fBaYH.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.columbia.edu/~vjd1/driving_forces_basic.htm&quot; rel=&quot;noreferrer&quot;&gt;Image source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Specific mechanisms include (from the links above):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;the thickness and density of the overlying crust&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;given that mountains have 'crustal roots' into the upper mantle (asthenosphere), they can act as obstacles for mantle flow&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The heat energy within the mantle plume itself, as sources of radiogenic heat (e.g. uranium decay) are unevenly distributed.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Edited to include a recent theory involving tidal affects of the moon on our rotation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://tetide.geo.uniroma1.it/sciterra/sezioni/doglioni/Publ_download/2009RiguzzietalTectonophysics.pdf&quot; rel=&quot;noreferrer&quot;&gt;Can Earth's rotation and tidal despinning drive plate tectonics?&lt;/a&gt; (Riguzzi et al. 2009), who assert that the Earth's and the moon's rotation may play a pivotal role in plate movement, the evidence for this includes:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;1) plates move along a westerly polarized flow that forms an angle relative to the equator close&#xA;  to the revolution plane of the Moon; &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;2) plate boundaries are asymmetric, being their geographic polarity&#xA;  the first order controlling parameter; unlike recent analysis, the slab dip is confirmed to be steeper along&#xA;  W-directed subduction zones; &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;3) the global seismicity depends on latitude and correlates with the decadal&#xA;  oscillations of the excess length of day (LOD); &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;4) the Earth's deceleration supplies energy to plate tectonics&#xA;  comparable to the computed budget dissipated by the deformation processes;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-10-12T07:25:12.347" LastActivityDate="2014-10-12T07:25:12.347" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="2618" PostTypeId="1" AcceptedAnswerId="2620" CreationDate="2014-10-12T11:05:10.767" Score="6" ViewCount="334" Body="&lt;p&gt;I have been playing this game for a while and I like the city's setting. It seem to be placed on a rock platform, or a mesa maybe, connected to the mainland on the bottom-left. It also has some connection in the top left and middle right.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to know what this structure is called so I can find some real-life such occurrences in order to draw some fan-art for this game.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would also like to know, if possible, what sort of parameters does nature require to make such an effect. What kind of climate, rock combinations, that sort of thing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.ytimg.com/vi/ijMaNGAolQI/maxresdefault.jpg&quot; alt=&quot;https://i.ytimg.com/vi/ijMaNGAolQI/maxresdefault.jpg&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="993" LastEditorUserId="-1" LastEditDate="2017-03-10T09:42:50.670" LastActivityDate="2014-11-19T15:10:40.437" Title="What geologic features could this video game environment be modeled from, and how do they form?" Tags="|structural-geology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2619" PostTypeId="2" ParentId="2597" CreationDate="2014-10-13T00:43:36.693" Score="6" Body="&lt;p&gt;Any numerical model solution is inherently constrained by the equations being solved. You are probably aware that the inverse turbulence energy cascade exists in predominantly 2D flows. In oceans and atmospheres, this happens at approximate scale of Rossby radius of deformation and larger. Whether or not a numerical model is able to represent a physical process (i.e. 3D turbulence) really depends on the terms in the model equations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take for example the simplest 2D model representative of ocean and atmosphere, shallow water equations (SWE, writing non-conservative form for brevity here so don't give me a hard time):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\dfrac{\partial \mathbf{v}}{\partial t} =&#xA;-\mathbf{v}\cdot\nabla\mathbf{v} - f\mathbf{k}\times\mathbf{v}&#xA;-g\nabla h&#xA;$$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\dfrac{\partial h}{\partial t} = -\nabla(h\mathbf{v})&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\mathbf{v}$ is the 2D velocity, $f$ is Coriolis frequency, $g$ is gravitational acceleration and $h$ is the fluid depth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The linearized form of the SWE, i.e. $\mathbf{v}\cdot\nabla\mathbf{v}\approx0$ and $\nabla(h\mathbf{v})\approx H\nabla\cdot\mathbf{v}$, where $H$ is the mean fluid depth, has an analytical solution and is well known.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The non-linear term $\mathbf{v}\cdot\nabla\mathbf{v}$ allows for the fast growth of small perturbations, eventually resulting in eddy formation. In this model, the only dissipation is of numerical kind, and the only turbulence is of the 2D kind, supporting inverse energy cascade. In order to allow for 3D turbulence, a prognostic equation for vertical velocity $w$, including non-linear terms $\mathbf{v}\cdot\nabla w$ must be introduced to the model.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;if we know that it is a true 3D flow, is there any point in using highly resolved 2D simulations that attempt to resolve the scales that are typically involved in turbulence?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;If by this you mean, can I model 3D turbulence with a very-high resolution 2D model, the answer is no. 2D models are obtained by making an assumption that variations in the 3rd dimension are negligible compared to variations in the other 2 dimensions. It is this assumption that prohibits any 3D process to be part of the model solution. Sure, one can crank up horizontal resolution as much as they like, and the model will produce a solution, however that solution will always be inherently constrained by the initial assumptions made.&lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2014-10-13T02:49:49.873" LastActivityDate="2014-10-13T02:49:49.873" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2620" PostTypeId="2" ParentId="2618" CreationDate="2014-10-13T02:26:29.863" Score="2" Body="&lt;p&gt;A flatland with occasional huge rocks and abundant rivers and lakes. One possibility might be a plain that experienced glaciation, bringing in the erratic rocks and carving the landscape.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2014-10-13T02:26:29.863" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2621" PostTypeId="2" ParentId="2618" CreationDate="2014-10-13T08:42:34.043" Score="5" Body="&lt;p&gt;Looking at the landscape, it almost appears to be a highland, with steep valleys carved by a misty river - which suggests possible waterfalls.  I am reminded of Victoria Falls, on the border of Zimbabwe and Zambia (part of the landscape pictured below)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/GgZJ1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://nature-nest.com/some-of-the-most-beautiful-waterfalls-on-earth/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The geological processes that formed these features is summarised in the webpage &lt;a href=&quot;http://vicfalls.zimbabwe.co.za/Climate,_Geology,_Flora-travel/explore-victoria-falls-geology.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Geology of Victoria Falls&lt;/a&gt; as a series of tectonic and erosional activity over an ancient basaltic bedrock, forming a series of near parallel gorges (shown below and from the webpage linked before).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/MFEtw.jpg&quot; alt=&quot;enter image description here&quot;&gt; &lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-10-13T08:42:34.043" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2622" PostTypeId="2" ParentId="2616" CreationDate="2014-10-13T10:04:31.913" Score="3" Body="&lt;p&gt;As the likely main causes for the rate of tectonic shifts have already been laid out, I just wanted to give a brief argument on why we can &lt;em&gt;discard&lt;/em&gt; other sources (Planets, Galactic..) as sources for frictional energy in the Earth's interior.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tidal forces originate in &lt;em&gt;differential&lt;/em&gt; gravity forces (= 2 or more mechanically connected points of a body experiencing different gravitational forces).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Those forces scale as $\sim \frac{M_{central}}{R^3}$ (gravity decreases slower, as $\sim \frac{1}{R^2}!)$. Also we know that in certain Sun-Moon-alignments on Earth there happen certain events of very strong &lt;a href=&quot;http://en.wikipedia.org/wiki/Tide#Range_variation:_springs_and_neaps&quot; rel=&quot;nofollow&quot;&gt;neap tides&lt;/a&gt;. So we can conclude, that Solar tidal forces can still play a role in the Earth's interior.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But when we now want to scale this to planets of the solar system, distant molecular clouds, stars, central black hole, great attractor or whatever you want, we loose very fast any contribution to those forces.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't get however, how you want the CMB to contribute to tidal forces?&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2014-10-13T10:04:31.913" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2623" PostTypeId="1" CreationDate="2014-10-13T10:24:10.187" Score="8" ViewCount="1001" Body="&lt;p&gt;What is the total Earth's interior energy budget? &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;What is the heat flux per m&lt;sup&gt;2&lt;/sup&gt; that warms the Earth surface because of the Earthy's internal heat. &lt;/li&gt;&#xA;&lt;li&gt;How much of that heat is replenished from the radioactive decay? &lt;/li&gt;&#xA;&lt;li&gt;How much of that heat is replenished from Moon's tidal forces?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="943" LastEditorUserId="943" LastEditDate="2014-10-13T11:27:22.893" LastActivityDate="2014-10-22T10:41:54.967" Title="What is the total Earth's interior energy budget?" Tags="|geophysics|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2624" PostTypeId="1" CreationDate="2014-10-13T14:11:46.427" Score="7" ViewCount="273" Body="&lt;p&gt;What tools or resources are available (free) on the web to determine the probability of a given point on the earth to be at or above (or below) a specific temperature on a specific date.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Some [extreme] examples:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;At the South Pole, the probability of it being &gt; 90-F on June 1 approaches 0% (I'm guessing).&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Conversely, the probability of it being &amp;lt; 32-F on the equator (at or near sea level) on Dec 1 approaches 0%, as well.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another way to phrase what I'm looking for:  &lt;strong&gt;On what date in the calendar year does the probability of the air temperature being above (or below) &lt;em&gt;X&lt;/em&gt; approach 0% for a given location/city?&lt;/strong&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, say, for Washington, D.C.-- after (or before) what date in the year is it virtually impossible for the temperature to be above, say... 80-F?&lt;/p&gt;&#xA;" OwnerUserId="996" LastActivityDate="2014-10-14T19:31:22.287" Title="Resources to determine temperature probability for a given location on a given date" Tags="|meteorology|climate|temperature|open-data|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2625" PostTypeId="1" CreationDate="2014-10-13T21:48:01.757" Score="3" ViewCount="185" Body="&lt;p&gt;If a single butterfly can alter the future, then can't every single action keep the future in chaos? According to the question about butterfly effects, this must be so, is it not?  If this is an accurate description of the physical world, if so many things act continuously on other things, is there a way to predict anything or action at all?  If so, why are we worrying about it? &lt;/p&gt;&#xA;" OwnerUserId="837" LastEditorUserId="87" LastEditDate="2014-11-19T15:14:50.530" LastActivityDate="2014-11-19T15:14:50.530" Title="Is everything affecting everything on Earth?" Tags="|climate-change|atmospheric-circulation|earth-system|" AnswerCount="3" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="2626" PostTypeId="2" ParentId="2625" CreationDate="2014-10-13T21:56:18.900" Score="-5" Body="&lt;p&gt;From experience as a cross continent truck owner-operator, the effect of an insect's beating wings on the earth is minimized or even neutralized by the mass of the truck when it hits the radiator. Logical thinking and close observation reveals this minimizing effect.  Just like when we hauled 285,000,000 honey bees, their combined flying power was too minimal to offset the mass of 35,000 pounds accelerating down the open road at 60 mph.&#xA;By inference therefore, the added weight of one bug plastered to our radiator does not alter the weight or speed of the vehicle.  If this logic bears out, then the beating of one set of wings of a lovely butterfly, will not be a deal breaker.&lt;/p&gt;&#xA;" OwnerUserId="837" LastActivityDate="2014-10-13T21:56:18.900" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2627" PostTypeId="2" ParentId="2625" CreationDate="2014-10-14T12:14:59.810" Score="9" Body="&lt;p&gt;Do you know what the weather will be in four hours time? You can probably make a very confident guess. How about this time tomorrow? You can probably make a reasonably confident guess. How about this time, in fourteen days exactly? Now, you're much less confident.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's because weather is a chaotic system, and it's very sensitive to boundary conditions.  In such a system, very small disturbances can make very big changes, far enough out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, for Wisconsin (as that's what the OP's profile gives as their location), let's think about the external air temperature at 05.00 on 1 February 2017, and at 14.00 on 1 July 2017. Which do you think will be higher? Will it be a difference of a few Kelvin, or more than ten Kelvin (18&amp;deg;F) difference? How confident are you in your answer? You're probably very very confident that the July temperature will be higher, by more than ten Kelvin. The climate is still reasonably predictable months or years ahead, even though it gets very hard to predict the weather reliably more than ten days ahead. Climate is a long-term system, and is not sensitive to boundary conditions in the same way that weather is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you roll a fair six-sided dice once, you can't be very confident about whether a one will come up, however much you know about the air movements in the room when you throw the dice (you can be reasonably sure that the probability is 1/6, however much you know about the air). However, if you roll that dice 6000 times, you can be reasonably confident that one will come up a thousand times, give or take a hundred times, and you don't need to know anything about the air movements in the room.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's the difference between weather and climate; even though weather is just a manifestation of climate, it's just a sample from the climate distribution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We've built the global economy, patterns of habitation and movement, food supplies, energy systems, around the climate that we've had for the last few hundred years. And that should be ok, because climate, sea levels and sea pH levels normally take between thousands and millions of years to change radically. But our releases of greenhouse gases are now causing big changes to happen within years to decades: and it will be enormously expensive, disruptive, and cause huge suffering to billions of people, to reorient the global economy, patterns of habitation and movement, food supplies, and energy systems, to newer, unknown, unfamiliar climates, coupled with rising sea levels and ocean acidification.&lt;/p&gt;&#xA;" OwnerUserId="100" LastActivityDate="2014-10-14T12:14:59.810" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2629" PostTypeId="2" ParentId="2624" CreationDate="2014-10-14T19:31:22.287" Score="1" Body="&lt;p&gt;The most basic way to measure probability is to look at historical &#xA;records. There are several sources for this data, including: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://wunderground.com&quot; rel=&quot;nofollow&quot;&gt;http://wunderground.com&lt;/a&gt; &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;ftp://ftp3.ncdc.noaa.gov/pub/data/noaa/isd-lite/&quot; rel=&quot;nofollow&quot;&gt;ftp://ftp3.ncdc.noaa.gov/pub/data/noaa/isd-lite/&lt;/a&gt; &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;This assumes no climate change. If you believe in climate change, you &#xA;will need to factor that in. &lt;/p&gt;&#xA;" OwnerDisplayName="user967" LastActivityDate="2014-10-14T19:31:22.287" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2630" PostTypeId="2" ParentId="2583" CreationDate="2014-10-14T19:45:03.783" Score="3" Body="&lt;p&gt;At a given location, measure the time between when Sirius (or any &#xA;star) is due south today and due south tomorrow. This is the sidereal &#xA;day, which is approximately 23h56m long. The more familiar 24h solar &#xA;day can be computed from the sidereal day. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To be absolutely precise, astronomers measure the due south time of &#xA;the vernal equinox, not an actual star. A sidereal day is the interval &#xA;between &quot;successive culminations of the vernal equinox&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The earth's solar day is increasing at a near-constant rate due to &#xA;(lunar) tidal friction. When scientists see a change that's not &#xA;consistent with this near-constant increase, they know it's due to &#xA;some other event. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might also want to ask in &lt;a href=&quot;http://astronomy.stackexchange.com&quot;&gt;http://astronomy.stackexchange.com&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerDisplayName="user967" LastActivityDate="2014-10-14T19:45:03.783" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2631" PostTypeId="1" CreationDate="2014-10-14T20:44:56.297" Score="10" ViewCount="136" Body="&lt;p&gt;The magnetic field of the Earth is produced by the &lt;a href=&quot;http://en.wikipedia.org/wiki/Dynamo_theory&quot; rel=&quot;nofollow noreferrer&quot;&gt;magnetic dynamo&lt;/a&gt;. What conditions must a rocky body possess in order to exhibit the dynamo? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clearly, the planet's interior must not be too cold. However, Venus for example, according to &lt;a href=&quot;http://en.wikipedia.org/wiki/Venus&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;, also lacks the dynamo although its interior is hot: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The lack of an intrinsic magnetic field at Venus was surprising given it is similar to Earth in size, and was expected also to contain a dynamo at its core. A dynamo requires three things: a conducting liquid, rotation, and convection. The core is thought to be electrically conductive and, although its rotation is often thought to be too slow, simulations show it is adequate to produce a dynamo. This implies the dynamo is missing because of a lack of convection in the Venusian core.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They offer explanation in which either:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Lack of plate tectonics reduces heat gradient and prevents convention in mantle.&lt;/li&gt;&#xA;&lt;li&gt;Inner core is solidified, missing or lacking temperature gradient.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I am interested in more complete list of conditions that are necessary, like for example in &lt;a href=&quot;https://earthscience.stackexchange.com/questions/996/what-properties-must-a-rocky-body-possess-in-order-to-exhibit-plate-tectonics&quot;&gt;this answer about plate tectonics&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="943" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-10-31T19:51:02.463" Title="What properties must a rocky body possess in order to exhibit the magnetic dynamo?" Tags="|geophysics|planetary-science|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2632" PostTypeId="1" CreationDate="2014-10-15T21:36:08.197" Score="19" ViewCount="648" Body="&lt;p&gt;Satellites such as GOCE and GRACE measure the geoid with unprecedented accuracy.  Altimeters can determine local surface elevation with millimetre-precision.  This makes me wonder: to what precision and accuracy can we measure (or calculate) the volume of the Earth?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm a lay when it comes to solid Earth, and I find it surprisingly hard to find even the order of magnitude of an answer ($10^0$ metre?  $10^3$ metre?  $10^{-3}$ metre?).  &lt;a href=&quot;https://en.wikipedia.org/wiki/Figure_of_the_Earth#Volume&quot;&gt;Wikipedia is extremely limited on the question&lt;/a&gt; and links to a surprisingly poor &lt;a href=&quot;http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html&quot;&gt;NASA factsheet&lt;/a&gt; that doesn't include any error estimates, cites no sources, and is imprecise in providing context or defining what it's talking about.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One can calculate the volume of Earth using semi-major and minor axes obtained from reference ellipsoids, but I have no idea how large an error is introduced by this approximation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the precision and accuracy do we know the shape of the Earth?&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorDisplayName="user12525" LastEditDate="2019-04-21T10:37:04.873" LastActivityDate="2019-04-21T10:37:04.873" Title="To what accuracy and precision do we know the volume of the Earth?" Tags="|geology|geophysics|planetary-science|remote-sensing|geodesy|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2633" PostTypeId="2" ParentId="2491" CreationDate="2014-10-15T22:40:36.537" Score="4" Body="&lt;p&gt;Short answer: 0.2 times the total length of your cable(s).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;100m rollout --&gt; ~20m depth&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bear in mind that the deeper you get, the more you have to be careful with your data interpretation. Also if you do a roll-along your depth doesn't get deeper. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Long answer see &lt;a href=&quot;http://www.heritagegeophysics.com/papers/Depth_of_investigation.pdf&quot; rel=&quot;nofollow&quot;&gt;Bernard J (2003): Short note on the depth of investigation of electrical methods. Heritage Geophysics&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="364" LastEditorUserId="124" LastEditDate="2014-10-16T07:08:09.397" LastActivityDate="2014-10-16T07:08:09.397" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2634" PostTypeId="2" ParentId="2232" CreationDate="2014-10-15T23:36:53.790" Score="8" Body="&lt;p&gt;You do have an earth analogue for this. The Namib Desert in Namibia has been a desert for the past 2 million years with very little precipitation. Also the Atacama Desert is hyperarid since more than 25 million years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mars is probably a planet that has below freezing temperatures for million of years, with only wind as an erosional process (apart of a few gravitative processes).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Granite is weathering in roundish forms, as it takes no clear direction from crystallisation. Usually the granite erodes in arid landscapes because of temperature changes and tiny differences in moisture and salts. In a completely frozen plant without a strong atmosphere you would probably still get round forms like Inselbergs.&#xA;Furthermore there are of course different kind of forms of wind erosion resulting in strange looking shapes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;High mountain ranges on earth are always limited by erosion from water or glaciers (frozen water) in their growth, as there is more precipitation with altitude.&#xA;To get sharp mountains you will need plate tectonics, which will result in the formation of an atmosphere and the release of heat and water (I assume the formation of an atmosphere since platetectonics are associated with volcanismn, which will lead to water and other chemicals like CO2 being released). Thus you will get erosion from water. If the plate tectonics stop and the atmosphere disappears, the mountains will stop growing and there is no moisture left for erosional processes. Then erosion by wind will be the primary geomophological process and the planet could look like Mars.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(I admit this is highly speculative, but the question is speculative in itself.)&lt;/p&gt;&#xA;" OwnerUserId="364" LastEditorUserId="364" LastEditDate="2014-10-16T07:39:05.053" LastActivityDate="2014-10-16T07:39:05.053" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2636" PostTypeId="1" CreationDate="2014-10-16T09:04:01.460" Score="10" ViewCount="5610" Body="&lt;p&gt;Given, discharge data alone for each month in each year, is it possible to calculate the flow duration curve? Some of the discharge values in some months were found to be 0. Do we need to consider those values?&lt;/p&gt;&#xA;" OwnerUserId="1004" LastActivityDate="2017-08-13T01:10:15.830" Title="How to calculate flow duration curve for a set of 12 year data?" Tags="|hydrology|runoff|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2637" PostTypeId="1" AcceptedAnswerId="2645" CreationDate="2014-10-16T15:53:31.897" Score="6" ViewCount="481" Body="&lt;p&gt;I'm planning a high-altitude weather balloon project (to around 100000 feet, or 30 km) some time down the line to take video and pictures of near space altitudes and I have some questions I need to ask before doing so:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;What does the weight of a weather balloon mean such as 150 g, 500 g, 2000 g, etc mean?&lt;/li&gt;&#xA;&lt;li&gt;What diameter of weather balloon do I need? I'm planning to take upto around 1-2 kg of payload consisting of cameras, Arduino, Raspberry Pi, GPS, parachute etc.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="1006" LastEditorUserId="725" LastEditDate="2017-03-12T06:42:31.513" LastActivityDate="2017-03-12T06:42:31.513" Title="How do I interpret the specs of a weather balloon?" Tags="|meteorology|weather-forecasting|radiosounding|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2638" PostTypeId="2" ParentId="2632" CreationDate="2014-10-16T17:46:53.080" Score="10" Body="&lt;p&gt;One way to approach this is to treat the Earth as an oblate ellipsoid. This would mean the errors arise from the uncertainties in the Earth's equatorial radius and the flattening. From &lt;a href=&quot;http://link.springer.com/article/10.1007%2Fs00190-003-0373-y?LI=true&quot;&gt;Groten, &quot;Fundamental Parameters and Current (2004) Best Estimates of the Parameters of Common Relevance to Astronomy, Geodesy, and Geodynamics,&quot; &lt;em&gt;Journal of Geodesy&lt;/em&gt; 77:10-11, 724-797 (2004)&lt;/a&gt;, the Earth's equatorial radius in the mean tide system is 6378136.72±0.10 meters, and the inverse flattening is 1/f = 298.25231±0.00001. The uncertainty in volume due to the uncertainty in equatorial radius is about $3 V \frac{\Delta a}{a}$, where $V=\frac 4 3 \pi (1-f) a^3$, or about &lt;a href=&quot;http://www.wolframalpha.com/input/?i=4%2F3*pi*%286378136.72+m%29%5E3*%281-1%2F298.25231%29*3*%280.1+m%29%2F%286378136.72+m%29&quot;&gt;51,000 cubic kilometers&lt;/a&gt;. The uncertainty in volume due to the uncertainty in inverse flattening is tiny in comparison, about $V \frac {\Delta 1/f} {1/f (1/f - 1)}$, or about &lt;a href=&quot;http://www.wolframalpha.com/input/?i=4%2F3*pi*%286378136.72+m%29%5E3*%281-1%2F298.25231%29*0.00001%2F%28298.25231*297.25231%29&quot;&gt;120 cubic kilometers&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That 51,000 cubic kilometer figure sounds like a lot, but it's not. It means the volume of the Earth can be expressed to seven places of precision.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-10-16T17:46:53.080" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2639" PostTypeId="1" AcceptedAnswerId="2642" CreationDate="2014-10-16T18:03:57.337" Score="58" ViewCount="47304" Body="&lt;p&gt;According to NASA, &lt;a href=&quot;http://climate.nasa.gov/causes/&quot; rel=&quot;nofollow noreferrer&quot;&gt;causes of the Earth's greenhouse effect&lt;/a&gt; include water vapor, carbon dioxide, methane, nitrous oxide, and CFCs.  Carbon dioxide gets the most press, and NASA's page says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;). A minor but very important component of the atmosphere, carbon dioxide is released through natural processes such as respiration and volcano eruptions and through human activities such as deforestation, land use changes, and burning fossil fuels. Humans have increased atmospheric CO&lt;sub&gt;2&lt;/sub&gt; concentration by a third since the Industrial Revolution began. This is the most important long-lived &amp;quot;forcing&amp;quot; of climate change.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.ncsu.edu/project/treesofstrength/benefits.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;An article&lt;/a&gt; by NC State University says that a healthy tree can store 13 pounds of carbon per year.  As I understand it, carbon dioxide is processed by the tree: the carbon is stored, and the oxygen released.&lt;/p&gt;&#xA;&lt;p&gt;Given that, how many trees would I need to plant to solve the global climate change crisis?  Should I optimize for a specific type of tree, or would pine work as well as oak or black walnut?&lt;/p&gt;&#xA;" OwnerUserId="952" LastEditorUserId="952" LastEditDate="2020-12-23T19:27:47.963" LastActivityDate="2020-12-23T19:27:47.963" Title="How many trees would I have to plant to solve Global Warming?" Tags="|climate-change|carbon-cycle|" AnswerCount="5" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="2641" PostTypeId="2" ParentId="2632" CreationDate="2014-10-17T08:29:03.287" Score="7" Body="&lt;p&gt;Talking about the volume of the Earth, we have to ignore that it is not static but in fact highly dynamic. The tides alone make the height differ by up to 50 cm. The information I take is from a 2003 article from &lt;a href=&quot;http://www.esri.com/news/arcuser/0703/geoid1of3.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;esri&lt;/a&gt; by Witold Fraczek.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you said, we have different understandings of the Earth. Approximations are made to make calculations easier (and faster). We go from sphere to ellipsoid to geoid to actual measurements. One of these ellipsoid models is the &lt;a href=&quot;http://en.wikipedia.org/wiki/World_Geodetic_System&quot; rel=&quot;nofollow noreferrer&quot;&gt;WGS84&lt;/a&gt;, which is still maintained up to this day. Howver, when the GPS era started, satellites where having some serious troubles to get the heights right. Places would vary around 30-40 meters. So basically a better model had to be developed. &#xA;&lt;img src=&quot;https://i.stack.imgur.com/An6Bf.png&quot; alt=&quot;http://upload.wikimedia.org/wikipedia/commons/thumb/7/7a/Geoidheight_DE.svg/600px-Geoidheight_DE.svg.png&quot;&gt; (&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Geoidheight_DE.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;The geoid&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Geoid aren't as easy to calculate as you would think. The way it is actually done is by using gravitational measurements and the mean sea level (MSL). The image I used is from GRACE data, the most accurate model up to today. You can now use GIS to compute the variations from the reference ellipsoid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/uuznP.jpg&quot; alt=&quot;GRACE gravitational geoid&quot;&gt; (&lt;a href=&quot;https://www.jpl.nasa.gov/news/news.php?release=2007-147&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;The errors&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Let me just quote from the article:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The maximum range of the Geoid99 undulations with respect to the WGS84 ellipsoid is 192 meters. The biggest anomaly was discovered southeast of India where the geoid is 105 meters below the ellipsoid, and its highest swelling was observed in eastern Indonesia.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The geoid99 is far from perfect (and there are many newer models). However, from this we can see that the maximum error is in the 100m range, very localized too. Earth's topology is rather insignificant compared to the entire volume. I will not put a number down, as I don't have time right now to do any actual computations, but as a qualitative analysis this should give a basic idea.&lt;/p&gt;&#xA;" OwnerUserId="507" LastEditorUserId="725" LastEditDate="2017-03-12T06:49:41.570" LastActivityDate="2017-03-12T06:49:41.570" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2642" PostTypeId="2" ParentId="2639" CreationDate="2014-10-17T11:04:03.790" Score="49" Body="&lt;p&gt;In 2010 anthropogenic emissions (not including land use change) were approximately &lt;a href=&quot;http://cdiac.ornl.gov/ftp/ndp030/global.1751_2010.ems&quot; rel=&quot;noreferrer&quot;&gt;9167 million metric tonnes&lt;/a&gt;.  Your data on trees holding 13 lbs (5.9 kg) of carbon per year equates to 169.6 trees per metric tonne of emissions.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to take up all of the emissions from 2010 you would need 1,545,000,000,000 trees.  A mature forest has only about &lt;a href=&quot;http://books.google.co.uk/books?id=ML3jtMUzRZgC&amp;amp;pg=PA123&amp;amp;lpg=PA123&amp;amp;dq=trees%20per%20acre%20mature%20forest&amp;amp;source=bl&amp;amp;ots=YrctJbM_L7&amp;amp;sig=gL5m4Uma36o1QM1bpl45fHswQkE&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ei=TPRAVP_QGfHg7QayyYH4DQ&amp;amp;ved=0CCMQ6AEwAA#v=onepage&amp;amp;q=trees%20per%20acre%20mature%20forest&amp;amp;f=false&quot; rel=&quot;noreferrer&quot;&gt;100 trees per acre&lt;/a&gt; (400 per hectare), so you would need 15,545,000,000 acres of mature forest.  This equals an area of 24,290,000 mi&lt;sup&gt;2&lt;/sup&gt; (62,910,000 km&lt;sup&gt;2&lt;/sup&gt;).  This is approximately the land area of &lt;a href=&quot;https://www.infoplease.com/world/world-geography/world-land-areas-and-elevations&quot; rel=&quot;noreferrer&quot;&gt;Asia, Europe, and Australia combined&lt;/a&gt;!&lt;br&gt;&#xA;The surface area of land on the planet is about &lt;a href=&quot;http://en.wikipedia.org/wiki/Earth&quot; rel=&quot;noreferrer&quot;&gt;150,000,000 km&lt;sup&gt;2&lt;/sup&gt;&lt;/a&gt;, so in principle we would need to add cover onto 42% of the current land (or we could take soil from deep ocean floors to landfill 1/5th of the oceans!) in order to plant enough trees to solve the problem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This also assumes that the 13 pounds (5.9 kg) of carbon figure is for mature forests, rather than for growing trees (see comments for further discussion).  If this value is for young developing trees, it would indicate less be attainable in the longrun.  If the 13 pounds is for a developed forest, perhaps a greater amount could be removed in early years as a temporary quicker fix.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is also the problem that forested land is likely to have a lower albedo than the land surface that it covers, and hence the planet will reflect less sunlight back into space which would lead to some extra warming, so we would also need to compensate for that somehow.  Apparently &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_countries_by_forest_area&quot; rel=&quot;noreferrer&quot;&gt;about 26% of Earth's land&lt;/a&gt; is already covered with forests.  I rather doubt over half of the uncovered land surface is suitable for new forests, the continents have large bands either side of the equator that are generally too arid, and the regions close to the poles are too cold.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short, it isn't going to work, even with the most generous assumptions about forest CO&lt;sub&gt;2&lt;/sub&gt; exchanges (unless of course I have made an arithmetic error, which is definitely a possibility).&lt;/p&gt;&#xA;" OwnerUserId="624" LastEditorUserId="6298" LastEditDate="2017-11-03T11:48:33.100" LastActivityDate="2017-11-03T11:48:33.100" CommentCount="17" ContentLicense="CC BY-SA 3.0" />
  <row Id="2643" PostTypeId="2" ParentId="890" CreationDate="2014-10-17T11:16:53.823" Score="13" Body="&lt;p&gt;As mentioned in the comments, &lt;a href=&quot;http://en.wikipedia.org/wiki/List_of_U.S._states_by_elevation&quot;&gt;the 1km difference in average elevation&lt;/a&gt; of Wyoming in comparison to Montana plays a major role, as from the website &lt;a href=&quot;http://www.wrds.uwyo.edu/sco/wyoclimate.html&quot;&gt;Wyoming State Climate Office&lt;/a&gt;,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Because of its elevation, Wyoming has a relatively cool climate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, there is a bit more to it than that, the presence of numerous valleys&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;provide ideal pockets for the collection of cold air drainage at night. Protecting mountain ranges prevent the wind from stirring the air, and the colder heavier air settles into the valleys often sending readings well below zero.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-10-17T11:16:53.823" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2644" PostTypeId="1" CreationDate="2014-10-17T13:07:43.423" Score="11" ViewCount="359" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Lake_Toba&quot; rel=&quot;noreferrer&quot;&gt;Lake Toba, Indonesia&lt;/a&gt; is a supervolcano which was the site of &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;a massive supervolcanic eruption estimated at VEI 8 that occurred 69,000 to 77,000 years ago, representing a climate-changing event. It is the largest known explosive eruption on Earth in the last 25 million years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It is believed by some scientist to have caused the &lt;a href=&quot;http://en.wikipedia.org/wiki/Toba_catastrophe_theory&quot; rel=&quot;noreferrer&quot;&gt;Toba Catastrophe Theory&lt;/a&gt;, resulting in a 'bottleneck' in early human populations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The region is most definitely still &lt;a href=&quot;http://en.wikipedia.org/wiki/Lake_Toba#More_recent_activity&quot; rel=&quot;noreferrer&quot;&gt;very active&lt;/a&gt; with continuing seismic and volcanic activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What would be the precursors to a repeat of a Lake Toba super-eruption?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="6298" LastEditDate="2021-09-13T19:22:54.273" LastActivityDate="2021-12-04T11:58:13.983" Title="What would be the precursors to a repeated Lake Toba super eruption?" Tags="|volcanology|volcanic-hazard|volcanic-eruption|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="2645" PostTypeId="2" ParentId="2637" CreationDate="2014-10-17T14:53:11.770" Score="9" Body="&lt;p&gt;The weight of a balloon determines most of its specifications, though I'm not sure if they are generalized or specific to a manufacturer.  Looking at &lt;a href=&quot;http://kaymontballoons.com/Weather_Forecasting.html&quot;&gt;one supplier&lt;/a&gt; we can get a feel for what you need.  For a 1 kg payload it looks like you'd want a minimum of a 1200g balloon.  According to the site linked, this 1200g balloon will have:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;6.0 ft diameter at launch&lt;/li&gt;&#xA;&lt;li&gt;113 ft$^3$ volume at release&lt;/li&gt;&#xA;&lt;li&gt;320 fpm ascent rate&lt;/li&gt;&#xA;&lt;li&gt;28 ft diameter at burst&lt;/li&gt;&#xA;&lt;li&gt;109,000 ft altitude at burst&lt;/li&gt;&#xA;&lt;li&gt;1190 g free lift &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;If you need 2kg of payload you'd need to size a bigger balloon.  In general your application is not different from the specs of a normal upper-air sounding launch, so you should be able to spec your balloons directly from suppliers of sounding balloons.  All of the balloons for a 1-2 kg payload should burst above 100,000 feet so it just a matter of picking a supplier and a balloon sized for your payload (per the manufacturer specifications).&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-10-17T14:53:11.770" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="2646" PostTypeId="2" ParentId="2623" CreationDate="2014-10-17T18:51:19.897" Score="7" Body="&lt;p&gt;If you see wikipedia here:&#xA;en.wikipedia.org/wiki/Earth's_internal_heat_budget&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They have a nice summary of the answer I think you are looking for:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The flow of heat from Earth's interior to the surface is estimated at 47 terawatts and comes from two main sources, the radiogenic heat produced by the radioactive decay of isotopes in the mantle and crust and the primordial heat left over from the formation of the Earth. Earth's internal heat powers most geological processes and drives plate tectonics. Despite its geological significance, this heat energy coming from Earth's interior is actually only 0.03% of Earth's total energy budget at the surface, which is dominated by 173,000 TW of incoming solar radiation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You can divide by the surface area of the Earth to get your rate per square meter.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2014-10-18T04:38:29.973" LastActivityDate="2014-10-18T04:38:29.973" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2647" PostTypeId="1" AcceptedAnswerId="2649" CreationDate="2014-10-17T19:08:35.517" Score="16" ViewCount="514" Body="&lt;p&gt;With some informal conversation with a peer of mine, he had suggested that there is evidence (which he couldn't find,but had remembered reading) that there was Silicon in the Earth's core. I referred to him to a rather famous paper by Micheal Drake which says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Further, there is no compelling experimental evidence that Si is extracted into the core under present core-mantle boundary conditions. For example, at the base of a high pressure/temperature terrestrial magma ocean, the metal/silicate partition coefficent for Si is approximately $10^{-3}$ to  $10^{-2}$&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But since this paper was published 12 years ago, I am wondering if there is any compelling evidence that Si is in Earth's core, and at what concentration it might be? How might it have gotten there? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Drake, M., Righter, K., 2002. Determining the composition of the Earth. Nature 416, 39–44.&lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="20" LastEditDate="2014-10-18T02:04:34.850" LastActivityDate="2021-01-26T09:50:51.247" Title="How much silicon is in the Earth's core, and how did it get there?" Tags="|geophysics|seismology|geochemistry|planetary-science|core|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2648" PostTypeId="2" ParentId="308" CreationDate="2014-10-17T20:27:43.940" Score="4" Body="&lt;p&gt;The article &lt;a href=&quot;http://www.earth.ox.ac.uk/~conallm/Caled.pdf&quot; rel=&quot;nofollow&quot;&gt;The Caledonian Orogeny redefined&lt;/a&gt; (McKerrow et al. 2000) have done exactly that - correlating the stratigraphic and orogenic aspects of all of the orogenic movements (as you have listed) that they define as being orogenic phases comprising the Caledonian Orogeny.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An important distinction the McKerrow et al. make is to state that the term 'Caledonian Orogeny' is not a single event, but rather comprised of all the tectonic movements that occurred in the ~200 million year development and closing of the ancient Iapetus Ocean, through the Cambrian to Devonian.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With this framework, the authors were able to determine a continuous stratigraphy through deposits of the tectonic events of the Caledonian Orogeny in the present day North American and European continents.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-10-17T20:27:43.940" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2649" PostTypeId="2" ParentId="2647" CreationDate="2014-10-17T22:21:18.030" Score="12" Body="&lt;p&gt;The only way presently is to simulate the conditions in the core, as has been performed in the article &lt;a href=&quot;https://doi.org/10.1016/j.epsl.2011.08.004&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oxygen and silicon contents of Earth's core from high pressure metal–silicate&#xA;partitioning experiments&lt;/a&gt; (Ricolleau et al. 2011), whose results indicate that&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;that the oxygen metal–silicate partition coefficient increases&#xA;with increasing oxygen fugacity, temperature and pressure, whereas the silicon metal-silicate partition coefficient increases with decreasing oxygen fugacity, increasing temperature and pressure.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The model also revealing that the approximate concentration of silicon in the core (outer core) is up to 11 wt%, depending on what model of core formation was used in the simulation.  These results&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;in the core could satisfies the seismologically observed range of outer core&#xA;density deficits.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In terms of how long the silicon is believed to have been in the core, in the article &lt;a href=&quot;http://www.nature.com/nature/journal/v447/n7148/full/nature05927.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Silicon in the Earth’s core&lt;/a&gt; (Georg et al. 2007), similarities with the silicon content with the Moon led to their conclusion that&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$Si$&lt;/span&gt; was already incorporated as a light element in the Earth’s core before the Moon formed.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="18081" LastEditDate="2021-01-26T09:50:51.247" LastActivityDate="2021-01-26T09:50:51.247" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="2650" PostTypeId="2" ParentId="2644" CreationDate="2014-10-18T14:22:48.253" Score="1" Body="&lt;p&gt;If I understand right, you want to know if we would notice signs of an eruption before the actual eruption?&#xA;As is written in the article that you cite, the region is still very active, but being active doesn't mean that anything will happen any time soon. A volcano can be active for millions of years, without much happening. It just means that there is a magma chamber and some heat transfer to the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If Toba would erupt we might notice some sings in advance. Probably there would be some increased geomthermal heatflux. Hot springs would get more active, the earth surface would uplift, etc... And then after a few days/weeks/months the actual eruption might happen.&#xA;But the eruption may also happen quite surprising.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think this question is not specific to Toba, but rather to volcanic eruptions in general. there is a lot of literature about that. You may want to start with &lt;a href=&quot;http://en.wikipedia.org/wiki/Prediction_of_volcanic_activity&quot; rel=&quot;nofollow&quot;&gt;the wikipedia article on that topic&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="364" LastActivityDate="2014-10-18T14:22:48.253" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2651" PostTypeId="2" ParentId="2625" CreationDate="2014-10-18T22:55:55.637" Score="6" Body="&lt;p&gt;The media loves the butterfly effect, but they also love to mis-portray what it means. When Lorenz gave his talk &lt;a href=&quot;http://eaps4.mit.edu/research/Lorenz/Butterfly_1972.pdf&quot;&gt;&quot;Predictability: Does the Flap of a Butterfly’s Wings in Brazil Set Off a Tornado in&#xA;Texas?&quot;&lt;/a&gt;, that made the media pay attention to the emerging field of chaos theory. The media focused on the title of his talk. It sounds so cool! They didn't read the body of the paper to see what it was all about.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The title was chosen to be provoke thought, not chaos. Lorenz did not mean that everything is interconnected. The butterfly effect simply means that chaotic systems are very sensitive to initial conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lorenz started his talk with&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... The question which really interests us is whether they can do even this—whether, for example, two particular weather situations differing by as little as the immediate influence of a single butterfly will generally after sufficient time evolve into two situations differing by as much as the presence of a tornado. In more technical language, is the behavior of the atmosphere unstable with respect to perturbations of small amplitude?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;He ends it with&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We must therefore leave our original question unanswered for a few more years, even while affirming our faith in the instability of the atmosphere. Meanwhile, today’s errors in weather forecasting cannot be blamed entirely nor even primarily upon the finer structure of weather patterns. They arise mainly from our failure to observe even the coarser structure with near completeness, our somewhat incomplete knowledge of the governing physical principles, and the inevitable approximations which must be introduced in formulating these principles as procedures which the human mind or the computer can carry out.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That extreme sensitivity to initial conditions means that in theory, a scenario in which a butterfly in Brazil does or does not flag its wings just so are enough to create slightly different conditions that eventually result in tornado hitting Texas. Even if this is the case (and Lorenz did leave that as an open question in hist talk), it's not quite fair to say that the butterfly caused the tornado. The Lyapunov time for the disturbances created by a flap of a butterfly wing is very short. Saying that some event caused some later event else when the two events are separated by hundreds of Lyapunov times just doesn't make sense.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What this means is that forty plus years after Lorenz's talk, weather forecasters still can't make an accurate two week forecast, and they may well not ever be able to do so. They can make now a fairly accurate five or seven day forecast, and that was something that was beyond the skills of meteorologists forty years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Caveat: Don't believe the forecast by your local TV station. They are notoriously inaccurate. If the US National Weather Service says there's a 100% chance of rain tomorrow, it's best to cancel your barbecue. If your local TV station weatherman says the same, there's a good chance tomorrow will be sunny.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-10-18T22:55:55.637" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2652" PostTypeId="1" AcceptedAnswerId="2677" CreationDate="2014-10-19T08:58:49.437" Score="11" ViewCount="4622" Body="&lt;p&gt;Measuring the length of a coastline depends on the scale of the measuring tool. The smaller the scale of your tool, the longer will your measured coastline be. The reason for this is the fractal property of coastlines. This is well known since a paper by Benoît Mandelbrot &lt;a href=&quot;http://en.wikipedia.org/wiki/How_Long_Is_the_Coast_of_Britain%3F_Statistical_Self-Similarity_and_Fractional_Dimension&quot; rel=&quot;nofollow&quot;&gt;&quot;How Long Is the Coast of Britain? Statistical Self-Similarity and Fractional Dimension&quot;&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now I was wondering if there is a standardized mapping scale to come up with global or country wise numbers of coastline length?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And furthermore, if there even is a general rule for all mapping purposes, which scale is to be used in mapping?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there maybe even something like an ISO standard for this?&lt;/p&gt;&#xA;" OwnerUserId="364" LastEditorUserId="28050" LastEditDate="2016-04-13T13:48:46.313" LastActivityDate="2016-04-13T13:48:46.313" Title="Standardized scale for coastline length or mapping in general?" Tags="|measurements|geography|mapping|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2657" PostTypeId="1" AcceptedAnswerId="2662" CreationDate="2014-10-20T05:46:28.937" Score="12" ViewCount="1785" Body="&lt;p&gt;I have been searching certain fluorescent minerals, such as Andersonite, and all websites are saying how the mineral will glow if exposed to Ultraviolet light. Does enough ultraviolet light come through the atmosphere (from the sun), to make any natural minerals actually glow, and to keep glowing for a time if the light was removed? If there is not enough UV light, or if no such mineral exists, would it be possible for such a mineral to exist?&lt;/p&gt;&#xA;" OwnerUserId="958" LastEditorUserId="958" LastEditDate="2014-10-20T14:43:15.143" LastActivityDate="2015-01-23T11:40:36.520" Title="Is it possible for a natural fluorescent mineral to glow from the sun's rays?" Tags="|atmosphere|minerals|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2658" PostTypeId="1" CreationDate="2014-10-20T06:19:44.930" Score="8" ViewCount="1932" Body="&lt;p&gt;After having studied the thin sections of basalt under the microscope, I have come across many spherulitic structures occurring in clusters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can this happen?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it due to devitrification or is it something else? What is the natural process behind formation of such structures? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image for reference:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/6gCWQ.jpg&quot; alt=&quot;Microscopic analysis of slide&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="1011" LastEditorUserId="20" LastEditDate="2014-10-25T15:05:11.420" LastActivityDate="2014-12-17T06:58:02.453" Title="How are spherulitic structures formed in basalt rock?" Tags="|geology|mineralogy|petrology|petrography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2659" PostTypeId="2" ParentId="2657" CreationDate="2014-10-20T12:31:14.360" Score="7" Body="&lt;p&gt;I am not a minerals expert, and can't claim expertise on these particular materials. However, from a general physics / materials point of view I'm pretty sure the answer will be that,&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;There is more than enough UV in sunlight to make the minerals fluoresce, but...&lt;/li&gt;&#xA;&lt;li&gt;The amount of visible light from the fluorescence is low enough to be undetectable by eye on top of the incoming sunlight.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;It would be easy to test this by putting a black enclosure with a UV-admitting filter over the rocks and an observer's head... :-)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(if anybody with actual specific knowledge would like to confirm or deny this, I'd be very grateful!)&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2015-01-23T11:40:36.520" LastActivityDate="2015-01-23T11:40:36.520" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2660" PostTypeId="2" ParentId="2623" CreationDate="2014-10-20T13:54:21.603" Score="5" Body="&lt;p&gt;According to &lt;a href=&quot;http://journals.aps.org/prd/abstract/10.1103/PhysRevD.76.043523&quot; rel=&quot;nofollow&quot;&gt;Towards closing the window on strongly interacting dark matter: Far-reaching constraints from Earth’s heat flow PHYSICAL REVIEW D 76, 043523 (2007)&lt;/a&gt; and references cited therein, the heat flux from Earth's interior to the surface is $44.2 \pm 1$ terawatts, or $0.087 \pm 0.002 W/m^2$.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of the 44.2 TW, 40% is attributable to radioactive decay of uranium and thorium.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The remainder is usually attributed an unknown amount from potassium decay and cooling from an initial high temperature; however, it cannot be ruled out that a significant fraction is from interaction of dark matter with Earth.&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2014-10-20T14:38:22.963" LastActivityDate="2014-10-20T14:38:22.963" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2661" PostTypeId="1" CreationDate="2014-10-20T16:13:33.780" Score="9" ViewCount="83" Body="&lt;p&gt;The &lt;a href=&quot;https://mesonet.agron.iastate.edu/GIS/goes.phtml&quot; rel=&quot;noreferrer&quot; title=&quot;WMS server of Iowa State&quot;&gt;WMS server of Iowa State&lt;/a&gt; is serving data for the GOES-13 satellite in the visible channel. As best as I can tell, the data is misaligned with other data sources. For example, in a WMS client, superimposing Blue Marble data, or any data containing political boundary lines, over on top of the Visible GOES-13 data from Iowa State, results in an apparent misalignment. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Iowa State data (I think) is displaced about 6 pixels towards the east. You can see it here, towards the middle of the image, where the land comes to a point (North Cape, Prince Edward Island, Canada, 47.06N, -64.00W).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/DdDGB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Iowa State re-projects the raw feed from NOAA into EPSG:4326 using something called GDAL. Here is their code:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://github.com/akrherz/pyWWA/blob/master/gini2gis.py#L160&quot; rel=&quot;noreferrer&quot;&gt;https://github.com/akrherz/pyWWA/blob/master/gini2gis.py#L160&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My questions. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Can you confirm using your own WMS client that the problem exists, and lies with the Iowa State WMS server?&lt;/li&gt;&#xA;&lt;li&gt;From a &lt;em&gt;cursory&lt;/em&gt; examination, do you see anything weird in the Iowa State code that does the re-projection?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I have been in contact with Iowa State about the issue, but unfortunately they aren't pursuing it.&lt;/p&gt;&#xA;" OwnerUserId="669" LastEditorUserId="124" LastEditDate="2014-10-21T05:42:33.073" LastActivityDate="2014-10-21T05:42:33.073" Title="Iowa State GOES Visible Data - misaligned EPSG:4326" Tags="|remote-sensing|projection|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2662" PostTypeId="2" ParentId="2657" CreationDate="2014-10-20T17:35:32.953" Score="9" Body="&lt;p&gt;The lifetime of a fluorescence excited state is on the nanosecond to microsecond time scale.  So once the excitation source light is removed, the emission of light will stop within microseconds. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that &lt;a href=&quot;http://en.wikipedia.org/wiki/Fluorescence&quot;&gt;fluorescence&lt;/a&gt; is distinct from &lt;a href=&quot;http://en.wikipedia.org/wiki/Phosphorescence&quot;&gt;phosphoresence&lt;/a&gt;, and phosphorescence can involve longer lifetime excited states.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://pubs.acs.org/doi/pdf/10.1021/es049417l&quot;&gt;Spectroscopic Characterization of the Uranium Carbonate Andersonite&lt;/a&gt; provides quantitative information on fluorescence lifetimes for Andersonite, and lifetimes are in the microsecond range.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding phosphorescence, see &lt;a href=&quot;https://archive.org/details/phosphorescenceo00phip&quot;&gt;Phosphorescence; or, The emission of light by minerals, plants, and animals (1862)&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;SEVERAL substances manifest the strange property  of emitting light&#xA;  when they are placed in darkness,  after having been exposed for some&#xA;  time to the  direct rays of the sun. In some cases a very short &#xA;  exposure to sunlight is sufficient to excite the  manifestation of&#xA;  this remarkable property, and in  others the direct rays of the sun&#xA;  are not necessary :  it suffices that the substance experimented upon &#xA;  be exposed to the dull light of a cloudy day. To  this phenomenon the&#xA;  denomination of Phosphores-  cence after insolation has been given. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;' The substances which possess this property in  the highest degree&#xA;  are the Bologna stone, or solar  phosphorus, certain varieties of&#xA;  fluor-spar and  carbonate of lime, some fossils, calcined shells or &#xA;  pearls, phosphate of lime, arseniate of lime, etc.  Many diamonds&#xA;  shine with brilliancy in the dark  if they have previously undergone&#xA;  an exposure of  some seconds' duration only to solar light. But  no&#xA;  substance surpasses in this respect sulphuret  of barium. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;It is now a long time since the cobbler of Bologna,,  in Italy,&#xA;  astonished and amused his friends with a  peculiar substance since&#xA;  known as Bologna phosphorus, Bologna stone, or Solar phosphorus,&#xA;  which  shines brightly in the dark after having been placed  in the&#xA;  sunlight for some time. This substance is  sulphuret of barium. The&#xA;  cobbler prepared it by  heating red-hot with charcoal a piece of&#xA;  sulphate  of baryta, or Barytine, (Fig. I,) a stone which he...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2014-10-22T11:12:37.067" LastActivityDate="2014-10-22T11:12:37.067" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2663" PostTypeId="2" ParentId="2616" CreationDate="2014-10-20T19:44:15.640" Score="0" Body="&lt;p&gt;OCTOBER 20, 2014&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Q:  Is it known what determines the rate with which plate tectonics occur?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A:  It is existential, natural and random in nature caused by so many factors that we believe there is no opportunity for influence by celestial bodies outside our solar system, and we know enough about gravity, the atom, the universe, and the nature of existence to believe we have thoroughly investigated and believe our understandings/conclusions to be complete and finite.  We &quot;accept this as the whole truth and nothing but the truth&quot;???&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;I believe this to be succinct, to the point and accurate, but I don't like it&quot; - AR Oct 20, 2014.  Vote down if you don't like it and encourage some hypothetical wild speculation.  :-)&lt;/p&gt;&#xA;" OwnerUserId="809" LastActivityDate="2014-10-20T19:44:15.640" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2664" PostTypeId="2" ParentId="2658" CreationDate="2014-10-21T04:27:56.970" Score="7" Body="&lt;p&gt;According to the image that you provided, what you are seeing are &lt;strong&gt;not&lt;/strong&gt; spherulites, but rather epoxy bubbles. More on that later. I will first answer what are spherulites:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Spherical features observed in thin sections can form by several ways.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Devitrification - this is the recrystallisation of glass. I think it is more common in rhyolitic rocks than in basaltic rocks. As the glass is a non-stable amorphous phase, there is a solid state transition of the glass to quartz or feldspars. The centre of the spherulite is usually some kind of an disturbance in the glass. Could be a crystal nuclei or a small bubble. Here is a magnificent example of a spherulite in rhyolite, from the beautiful &lt;a href=&quot;http://microckscopica.altervista.org/en/&quot; rel=&quot;nofollow noreferrer&quot;&gt;collection&lt;/a&gt; of Bernardo Cesare:&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/O5EBP.jpg&quot; alt=&quot;spherulite&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;Filling of amygdules - this usually happens in more basic rocks, for example basalts. A rounded cavity is left due to the presence of gas bubbles during solidification. In this case, the minerals grow from the walls of the cavity inwards, filling the empty space (in contrast to the inside to outside growth pattern of spherulites). The minerals that grow are usually zeolites, clays, quartz and various other hydrothermal minerals. I remember seeing a magnificent example of epidote filling an amygdule once in a basalt. Here's an example of an amygdule from the &lt;a href=&quot;https://wwwf.imperial.ac.uk/earthscienceandengineering/rocklibrary/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Imperial College Rock Library&lt;/a&gt;:&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/xWW6u.jpg&quot; alt=&quot;enter image description here&quot;&gt;&#xA;Notice how it doesn't completely fill in the gas cavity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are the two most common ways in which this can form. &lt;strong&gt;However&lt;/strong&gt;, in your case I think the answer is less exciting than this. I am pretty sure that your rounded objects are &lt;strong&gt;simply bubbles in the epoxy&lt;/strong&gt;. Here's why:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;They are perfectly rounded. This rarely happens naturally.&lt;/li&gt;&#xA;&lt;li&gt;They are completely empty.&lt;/li&gt;&#xA;&lt;li&gt;The actual rock is to the left of that image. Most of the area covered in your image does not seem to have any real rock in it, unless it is glassy but I doubt it because there is rock on the left.&lt;/li&gt;&#xA;&lt;li&gt;That 4-sided halo around it occurs almost entirely in artificial bubbles created during the sample preparation process. You can put it a λ plate and see that opposite sides have similar colours (either red or blue).&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2014-12-17T06:58:02.453" LastActivityDate="2014-12-17T06:58:02.453" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2665" PostTypeId="5" CreationDate="2014-10-21T05:45:25.450" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-10-21T05:45:25.450" LastActivityDate="2014-10-21T05:45:25.450" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2666" PostTypeId="4" CreationDate="2014-10-21T05:45:25.450" Score="0" Body="Petrography is the science of observing and interpreting textural relationships of minerals and other features in rocks as observed through thin sections using an optical microscope." OwnerUserId="725" LastEditorUserId="725" LastEditDate="2014-10-21T17:00:45.220" LastActivityDate="2014-10-21T17:00:45.220" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2667" PostTypeId="1" CreationDate="2014-10-22T03:07:13.223" Score="9" ViewCount="1650" Body="&lt;p&gt;I'm having a bit of trouble figuring out a solution to this problem:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is an isothermal layer of air which has a temperature of 0 °C extending from the surface to 1 km height. A parcel is 0.5 °C is released at the surface in the isothermal layer. How high does the parcel rise before it descends back?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know what an isothermal layer is and I know that the parcel will rise until it reaches the surrounding air temperature. I am just not sure how or which formula I would use to solve the problem.&lt;/p&gt;&#xA;" OwnerUserId="920" LastEditorUserId="725" LastEditDate="2014-12-16T05:56:45.887" LastActivityDate="2014-12-16T05:56:45.887" Title="A parcel of air in an isothermal layer" Tags="|meteorology|atmosphere|homework|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2668" PostTypeId="2" ParentId="2667" CreationDate="2014-10-22T03:45:27.917" Score="9" Body="&lt;p&gt;Isothermal, as you are likely aware means constant temperature. Your problem has the givens:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The 0 - 1 km layer has a constant temperature of 0 C&lt;/li&gt;&#xA;&lt;li&gt;A surface parcel initially has a temperature of 0.5 C&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;We can likely assume the parcel is not saturated and you are aware that that a parcel with a positive relative temperature perturbation is buoyant and will rise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To question you need to look at next is: what happens to a parcel of air as it rises?  Your 0 - 1 km layer has a constant temperature but not a constant pressure so the parcel will expand as it rises.  If the parcel expands then its temperature will decrease.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At what rate does the temperature of an unsaturated parcel of air decrease as it rises?  This number will allow you to calculate the height that the parcels temperature decreases by 0.5 C and neutral buoyancy is attained. &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-10-22T03:45:27.917" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2669" PostTypeId="1" CreationDate="2014-10-22T06:09:04.257" Score="10" ViewCount="565" Body="&lt;p&gt;It's often said that, while warming and cooling have happened before, what is unusual about the current anthropogenic warming is that it's happening so fast, relative to previous warming phases$^1$. This is considered to be likely to contribute to mass species extinction, as some species will not be able to migrate or adapt fast enough.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the warming at the end of the Younger Dryas seems to have also happened quite fast. Is this period associated with any known extinction event?&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;$^1$: &lt;em&gt;&quot;It is thus clear that the current rate of global climate change is much more rapid and very unusual in the context of past changes.&quot;&lt;/em&gt; - &lt;a href=&quot;http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-6-2.html&quot;&gt;IPCC AR4 FAQ 6.2&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="56" LastEditorUserId="56" LastEditDate="2014-10-22T09:56:44.203" LastActivityDate="2014-10-22T09:56:44.203" Title="Is the Younger Dryas associated with an extinction event?" Tags="|global-warming|paleontology|mass-extinction|younger-dryas|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2670" PostTypeId="2" ParentId="939" CreationDate="2014-10-22T07:13:25.417" Score="3" Body="&lt;p&gt;You might want to study the QBO before hand-- but yes-- geomagnetism plays a factor in long term climate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.ann-geophys.net/17/925/1999/angeo-17-925-1999.pdf&quot; rel=&quot;nofollow&quot;&gt;http://www.ann-geophys.net/17/925/1999/angeo-17-925-1999.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1019" LastActivityDate="2014-10-22T07:13:25.417" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2671" PostTypeId="2" ParentId="2669" CreationDate="2014-10-22T07:17:23.783" Score="11" Body="&lt;p&gt;Some authors thinks that the extinction of the Pleistocene megafauna (large mammals such as mammoths, etc.) was contemporaneous with the Younger Dryas (&lt;strong&gt;Firestone et al. 2007; Faith &amp;amp; Surovell 2009&lt;/strong&gt;), while some thinks that it predates it by a couple thousand years (&lt;strong&gt;Gill et al. 2009&lt;/strong&gt;).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whether or not it was contemporaneous with the Younger Dryas, it constitutes a rather modest extinction event compared to the Big Five (i. e. the five bigger mass extinctions of the Phanerozoic: End Ordovician, Late Devonian, Permian/Triassic boundary, Triassic/Jurassic boundary and Cretaceous/Paleogene boundary, see &lt;a href=&quot;https://earthscience.stackexchange.com/a/952/87&quot;&gt;this previous answer of mine&lt;/a&gt; for more details on that), with nonetheless a noteworthy impact (e. g. &lt;strong&gt;Johnson 2009&lt;/strong&gt;) on the remaining ecosystem. The current/future mass extinction is however often considered to be at a comparable scale with these previous five (see for instance &lt;strong&gt;Barnovsky et al. 2011&lt;/strong&gt;), but climate change is not the only one to blame: active destruction of ecosystems, mainly through anthropization, is one major factor as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;References:&lt;br&gt;&#xA;Barnovsky et al., 2011. &lt;a href=&quot;http://dx.doi.org/10.1038/nature09678&quot; rel=&quot;nofollow noreferrer&quot;&gt;Has the Earth’s sixth mass extinction&#xA;already arrived?&lt;/a&gt; Nature, 471: 51-57.&lt;br&gt;&#xA;Faith &amp;amp; Surovell, 2009. &lt;a href=&quot;http://dx.doi.org/10.1073/pnas.0908153106&quot; rel=&quot;nofollow noreferrer&quot;&gt;Synchronous extinction of North America’s&#xA;Pleistocene mammals.&lt;/a&gt; PNAS, 106(49): 20641-20645.&lt;br&gt;&#xA;Firestone et al., 2007. &lt;a href=&quot;http://dx.doi.org/10.1073/pnas.0706977104&quot; rel=&quot;nofollow noreferrer&quot;&gt;Evidence for an extraterrestrial impact 12,900 years ago that contributed to the megafaunal extinctions and the Younger Dryas cooling.&lt;/a&gt; PNAS, 104(41): 16016-16021.&lt;br&gt;&#xA;Gill et al., 2009. &lt;a href=&quot;http://dx.doi.org/10.1126/science.1179504&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pleistocene Megafaunal Collapse, Novel Plant Communities, and Enhanced Fire Regimes in North America.&lt;/a&gt; Science, 326: 1100-1104.&lt;br&gt;&#xA;Johnson, 2009. &lt;a href=&quot;http://dx.doi.org/10.1098/rspb.2008.1921&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ecological consequences of Late Quaternary extinctions of megafauna&lt;/a&gt; Proc. Roy. Soc. B, 276 (1667): 2509-2519.&lt;br&gt;&#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-10-22T07:17:23.783" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2672" PostTypeId="2" ParentId="2623" CreationDate="2014-10-22T10:41:54.967" Score="1" Body="&lt;p&gt;I calculated the tidal heating of the Earth from the conservation of &lt;a href=&quot;https://en.wikipedia.org/wiki/Angular_momentum&quot; rel=&quot;nofollow&quot;&gt;angular momentum&lt;/a&gt; (total angular momentum of Earth-Moon system remains constant) and the fact that the Moon drifts away with rate &lt;a href=&quot;https://en.wikipedia.org/wiki/Lunar_distance_(astronomy)&quot; rel=&quot;nofollow&quot;&gt;3.8 cm / year&lt;/a&gt;. The resulting heating is approximately 3.2 TW, which finishes the list. Combining the answers from DavePhD and farrenthorpe and &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth&amp;#39;s_internal_heat_budget&quot; rel=&quot;nofollow&quot;&gt;Wikipedia&lt;/a&gt;, the total budget seems to be:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;em&gt;Radioactive decay:&lt;/em&gt; 15-41 TW&lt;/li&gt;&#xA;&lt;li&gt;&lt;em&gt;Residual heat:&lt;/em&gt; 12-30 TW&lt;/li&gt;&#xA;&lt;li&gt;&lt;em&gt;Tidal heating:&lt;/em&gt; 3.2 TW&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Total:&lt;/strong&gt; 44.2 TW&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I also found a nice overview &lt;a href=&quot;http://www.skepticalscience.com/heatflow.html&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="943" LastActivityDate="2014-10-22T10:41:54.967" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2673" PostTypeId="2" ParentId="2434" CreationDate="2014-10-22T13:13:56.340" Score="9" Body="&lt;p&gt;If U-shaped in cross-section, it is plausible that these are the partial remnants of &lt;a href=&quot;https://en.wikipedia.org/wiki/Lava_tube&quot;&gt;lava tubes&lt;/a&gt;. See, for example, &lt;a href=&quot;http://link.springer.com/article/10.1007/BF00304437&quot;&gt;Morphology and mechanism of eruption of postglacial shield volcanoes in Iceland (Rossi, 1996)&lt;/a&gt;. It is difficult to propose more detailed formation mechanisms in the absence of significantly more information about the structure.&lt;/p&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-10-22T13:13:56.340" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2675" PostTypeId="2" ParentId="2586" CreationDate="2014-10-22T13:32:52.120" Score="15" Body="&lt;p&gt;Factors determining the maximum possible height of mountains include the rate of uplift versus the rate of erosion[a] and rock strength.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rock strength is controlled by the type and internal structure of the rock in question. There is some evidence that once mountains extend above the snow line, glacial and periglacial erosion have a stronger control than exhumation/uplift rate (&lt;a href=&quot;http://www.sciencemag.org/content/276/5312/571.short&quot;&gt;Brozovic et al, 1997&lt;/a&gt;; &lt;a href=&quot;http://www.nature.com/nature/journal/v460/n7257/full/nature08263.html&quot;&gt;Egholm et al, 2009&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Everest and the Himalaya have reached their maximum possible elevation: the formation of the Tibetan plateau is due to the failure of rocks preventing the maintenance of discrete mountain peaks. The &lt;a href=&quot;http://www.sciencemag.org/content/276/5312/571.short&quot;&gt;principle of uniformitarianism&lt;/a&gt; suggests that - subject to differences in variables discussed by Egholm et al, including crustal composition - the Himalaya and Tibetan plateau are an excellent approximation to the maximum achievable height of mountain ranges. However, identifying &lt;em&gt;which specific&lt;/em&gt; palaeoranges were tallest (as opposed to calculating a plausible upper limit on height) is a significantly harder problem to solve.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[a] Though note that the rate of erosion increases as the rate of uplift increases - for more on erosional equilibrium, see e.g. &lt;a href=&quot;http://geology.gsapubs.org/content/28/9/803.short&quot;&gt;Riebe et al (2000)&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="105" LastActivityDate="2014-10-22T13:32:52.120" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2676" PostTypeId="1" CreationDate="2014-10-23T11:38:27.157" Score="9" ViewCount="800" Body="&lt;p&gt;I really need some reliable measured hourly weather data for a few sites across the world. It needs to include solar diffuse and direct values or their equivalents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've tried the usual sources: Met Office, Weather Underground and Weather Analytics but none of them provide what I need. They are either not hourly, don't contain solar radiation, or have difficult licence/ access restrictions. This is for some research to determine if there's any relation between position of sun, temperature, relative humidity, wind speed and direction. So I'd need a couple of years data for a couple of locations. Aggregate data isn't much use I'm afraid.&lt;/p&gt;&#xA;" OwnerUserId="1023" LastEditorUserId="100" LastEditDate="2014-10-23T17:12:03.070" LastActivityDate="2016-11-23T10:43:01.277" Title="Obtaining hourly weather data, including direct and diffuse insolation" Tags="|meteorology|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2677" PostTypeId="2" ParentId="2652" CreationDate="2014-10-23T15:40:24.860" Score="12" Body="&lt;p&gt;One standard that has be used by the USA is to measure the distant between points on the coast at intervals of 30 latitude minutes, as measured on a 1:1,200,000 scale map.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;See chapter 5 of &lt;a href=&quot;http://books.google.com/books?id=lT4q8-MKrrEC&amp;amp;pg=PA66&amp;amp;source=gbs_toc_r&amp;amp;cad=3#v=onepage&amp;amp;q&amp;amp;f=false&quot;&gt;Measurements from Maps: Principles and Methods of Cartometry&lt;/a&gt; by D. H. Maling for further information and other standards that have been used.  &lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2014-10-23T15:40:24.860" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2678" PostTypeId="2" ParentId="2676" CreationDate="2014-10-23T16:56:32.667" Score="8" Body="&lt;p&gt;If reanalysis data (&lt;a href=&quot;http://www.ecmwf.int/en/research/climate-reanalysis/era-interim&quot; rel=&quot;nofollow noreferrer&quot;&gt;ERA&lt;/a&gt;, &lt;a href=&quot;http://data-portal.ecmwf.int/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ECMWF&lt;/a&gt;, &lt;a href=&quot;http://cfs.ncep.noaa.gov/cfsr/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CSFRR&lt;/a&gt;) is too aggregate for you, try looking for the datasets used to calibrate photovoltaics models (&lt;a href=&quot;http://re.jrc.ec.europa.eu/pvgis/&quot; rel=&quot;nofollow noreferrer&quot;&gt;PVGIS&lt;/a&gt;, &lt;a href=&quot;http://pvwatts.nrel.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;PVWATTS&lt;/a&gt; and the like) - they include both direct and diffuse insolation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, follow the citation trail for papers that describe the calibration of the PV models, and the reanalysis models - some of the datasets you are seeking will be somewhere in that trail.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Barry Carter has pointed you at the NOAA ISD-Lite dataset, and I'd like to extend that pointer to the whole &lt;a href=&quot;https://www.ncdc.noaa.gov/isd&quot; rel=&quot;nofollow noreferrer&quot;&gt;Integrated Surface Data from NOAA&lt;/a&gt;, which is enormous: 20,000 global stations. Because it's an amalgamation of many different sources, they don't all share the same metadata, but &lt;a href=&quot;http://www1.ncdc.noaa.gov/pub/data/ish/ish-format-document.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this pdf&lt;/a&gt; lists the breadth of the metadata: the insolation variables are on pages 64-77.&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorDisplayName="user967" LastEditDate="2016-11-21T20:25:03.943" LastActivityDate="2016-11-21T20:25:03.943" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2679" PostTypeId="2" ParentId="2652" CreationDate="2014-10-23T22:56:43.490" Score="-4" Body="&lt;p&gt;It is not really worth worrying about unless you are proposing to walk along it, or let your pet ant walk along it, for the ant will have to walk a much greater distance than you as it follows all the wiggles that you just stride over. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nor does it matter a jot for coastal management, which is always concerned with water bodies or areas and never with the purely conceptual length of the coastline. Coastal reporting sometimes summarises water quality by length of affected coastline, but that is merely an administrative convenience and has no significance otherwise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The geometric length between two points defining a straight line does not depend on the size of the intervals we use to pace it out. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the length of a fractal coastline is quite different. The smaller the step, the greater the length. There are mathematical ways to express this and if you google around you will find them. Try looking for Koch Snowflake for example.&lt;/p&gt;&#xA;" OwnerUserId="1025" LastActivityDate="2014-10-23T22:56:43.490" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2680" PostTypeId="1" AcceptedAnswerId="2681" CreationDate="2014-10-24T10:33:38.730" Score="12" ViewCount="1176" Body="&lt;p&gt;Radius of the Fresnel zone is given by&#xA;$$Rf=(v/2)(t_0/f_\mathrm{dom})^{1/2}$$&#xA;where $v$: velocity of layer&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$t_0$: two way travel time&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$f_\mathrm{dom}$ :dominant frequency in the spectrum&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This shows that high frequencies give better resolution than lower frequencies and resolution deteriorates with depth and increasing velocities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However I found some text in &quot;Seismic Data Analysis- Yilmaz&quot; which is contradictory.&#xA;&quot;Just having low or high frequencies does not improve temporal resolution. Both low and high frequencies are needed to increase temporal resolution. This is demonstrated further in Figure 1.1-30.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/SOTTT.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could someone explain what the author is trying to say here or am I making a mistake in interpretation somewhere ?&lt;/p&gt;&#xA;" OwnerUserId="594" LastEditorUserId="725" LastEditDate="2014-12-17T07:03:52.927" LastActivityDate="2014-12-17T21:47:08.750" Title="Temporal Resolution of Seismic data" Tags="|geophysics|seismology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2681" PostTypeId="2" ParentId="2680" CreationDate="2014-10-24T11:08:04.287" Score="8" Body="&lt;p&gt;In seismic data analysis we have to distinguish between vertical (temporal) and horizontal resolution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The (First) Fresnelzone is linked to the vertical resolution and defines the area in which  the collected energy will still stack constructively.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The temporal resolution however, defines what the wave &quot;sees&quot;. The events can still be resolved if their thickness is within $\frac{\lambda}{4}$. However, in some cases it can go down to $\frac{\lambda}{32}$. This is a matter of detectability of events.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/th2L4.jpg&quot; alt=&quot;Seismic Resolution&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Don't forget that we're dealing with superpositions of different frequencies so basically low frequencies will give use the necesseray energy content of general trends, while high frequencies enable us to make a distinction between geologic features.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://folk.uio.no/hanakrem/svalex/E-learning/geophysics/Seismic_resolution.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;This file&lt;/a&gt; from the university of Oslo gives a nice overview.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(The picture is from a blog post I've written on &lt;a href=&quot;http://dramsch.net/archives/95-Know-your-scale-Why-wavelengths-are-so-important.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;knowing your wavelength&lt;/a&gt; it's CC-BY-SA &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Tardis_BBC_Television_Center.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source1&lt;/a&gt; &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Big_Ben_2013_February.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source2&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="507" LastActivityDate="2014-10-24T11:08:04.287" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2682" PostTypeId="2" ParentId="2507" CreationDate="2014-10-24T12:26:11.397" Score="5" Body="&lt;p&gt;First, don't take that graph too literally, it is just a cartoon version and isn't quantitatively correct.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The USSR heavily subsidized fertilizer until 1988.  When they ended the subsidy, fertilizer prices increased to market prices and use of fertilizer decreased.  Fertilizer use decreased further after the USSR fell a couple years later. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fertilizer use in France, Germany, UK and Japan &lt;a href=&quot;http://www.earth-policy.org/data_highlights/2014/highlights43&quot; rel=&quot;noreferrer&quot;&gt;peaked in the 1980s&lt;/a&gt; and contributed to the decline. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/wfgiG.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2014-10-24T12:26:11.397" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2683" PostTypeId="1" CreationDate="2014-10-24T12:59:14.797" Score="20" ViewCount="1097" Body="&lt;p&gt;I'm an intelligent and well-educated guy, but all of my schooling has been in economics, statistics, and public policy. I'm interested in reading a thorough explanation/defense of the scientific understanding of anthropogenic climate change that is intended for somebody who doesn't know anything about meteorology or climate science. However, I'm also looking for something fairly academically/scientifically rigorous. Something on the level of &quot;An Inconvenient Truth&quot; is probably just going to annoy me more than anything.&lt;/p&gt;&#xA;" OwnerUserId="1026" LastEditorUserId="100" LastEditDate="2014-10-24T14:41:31.033" LastActivityDate="2017-06-05T12:46:31.357" Title="Academic but accessible defense of the scientific understanding of anthropogenic climate change?" Tags="|climate-change|human-influence|" AnswerCount="5" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2685" PostTypeId="2" ParentId="2683" CreationDate="2014-10-24T13:44:58.250" Score="21" Body="&lt;p&gt;The definitive place to start is the Summary for Policy Makers at the start of the &lt;a href=&quot;http://www.climatechange2013.org/&quot;&gt;IPCC AR5 Working Group 1&lt;/a&gt; on the physical science basis of climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This also acts as a suitable introduction to the massive rest of the physical basis report, and will, together with the contents table for the full report, enable a reader to quickly find the sections of interest that cover greater detail. And to burrow deeper again, if there are specific sections that you'd like to know more about, the thing to do is to follow through and read the references from those sections. &lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="543" LastEditDate="2014-10-24T20:07:37.017" LastActivityDate="2014-10-24T20:07:37.017" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2686" PostTypeId="2" ParentId="2683" CreationDate="2014-10-24T15:07:58.343" Score="7" Body="&lt;p&gt;Prof. Raymond Pierrehumbert's book the &lt;a href=&quot;http://www.cambridge.org/gb/academic/subjects/earth-and-environmental-science/climatology-and-climate-change/principles-planetary-climate&quot;&gt;Principles of Planetary Climate&lt;/a&gt; is a pretty good primer on the physics that drives climate.  I'm not too sure that the mainstream scientific view on anthropogenic climate change needs any more defense than say the mainstream scientific position on relativity, or any other scientific topic.  @EnergyNumbers suggestion of the IPCC AR5 WG1 report is spot on, however you probably want to start with something rather more basic before finding out what the mainstream scientific position actually says.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd also recommend &quot;&lt;a href=&quot;http://www.amazon.co.uk/Climate-Modelling-Primer-Kendal-McGuffie/dp/111994337X/&quot;&gt;A Climate Modelling Primer&lt;/a&gt;&quot; by Kendal McGuffie and Ann Henderson-Sellers for an introduction to the basics of climate modelling.&lt;/p&gt;&#xA;" OwnerUserId="624" LastEditorUserId="624" LastEditDate="2014-10-24T17:42:11.840" LastActivityDate="2014-10-24T17:42:11.840" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2688" PostTypeId="2" ParentId="2683" CreationDate="2014-10-24T22:05:27.710" Score="10" Body="&lt;p&gt;An excellent book that concisely summarizes the IPCC physical results (without much of the policy summary editorializing) is &lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/0470943416&quot;&gt;Global Warming, Understanding the Forecast&lt;/a&gt; by David Archer, 2nd ed 2011. There will presumably be an updated edition soon to cover the latest IPCC release.&lt;/p&gt;&#xA;" OwnerUserId="1030" LastActivityDate="2014-10-24T22:05:27.710" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2689" PostTypeId="2" ParentId="2683" CreationDate="2014-10-25T14:20:36.437" Score="8" Body="&lt;p&gt;You have an economics and statistics background - is it anywhere near &lt;em&gt;mathematical&lt;/em&gt; economics resp. &lt;em&gt;mathematical&lt;/em&gt; statistics? If so, you could spend hours over at &lt;a href=&quot;http://scienceofdoom.com/roadmap/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Science of Doom&lt;/a&gt;:  &lt;strong&gt;&lt;em&gt;Roadmap&lt;/em&gt;&lt;/strong&gt;. I would consider that &lt;em&gt;thorough&lt;/em&gt; on the rigorous part. (As an economist, you know the difference between the &lt;em&gt;laws&lt;/em&gt; at work, as opposed to the &lt;em&gt;econometrics&lt;/em&gt; that attempt at measuring precisely how much.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You will find books - table-of-contents and sample pages - at &lt;a href=&quot;http://scienceofdoom.com/2011/02/26/find-stuff-out-and-book-reviews/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Science of Doom&lt;/a&gt;: &lt;strong&gt;&lt;em&gt;Find Stuff Out and Book Reviews&lt;/em&gt;&lt;/strong&gt;.&lt;/p&gt;&#xA;" OwnerUserId="1031" LastEditorUserId="6093" LastEditDate="2017-06-05T12:46:31.357" LastActivityDate="2017-06-05T12:46:31.357" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2690" PostTypeId="2" ParentId="2683" CreationDate="2014-10-25T23:24:05.047" Score="5" Body="&lt;p&gt;A couple of other resources, aimed at educating the general public include:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NASA's page &lt;a href=&quot;http://climate.nasa.gov/evidence/&quot; rel=&quot;noreferrer&quot;&gt;Global Climate Change: Vital Signs of the Planet&lt;/a&gt;, go through the evidence, causes and effects, details the 'vital signs' of the planetary system and includes statements from various other organisations about the issue.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The USGS have the webpage &lt;a href=&quot;http://www.usgs.gov/climate_landuse/clu_rd/pt_nat_climate.asp&quot; rel=&quot;noreferrer&quot;&gt;Distinguishing Natural Climate Variability from Anthropogenic Climate Change&lt;/a&gt;, that, as the title suggests looks at how natural and anthropogenic forcings on the climate can be distinguished. Essentially, demonstrating the scientific basis for determining what is natural climate variation and what is anthropogenic forcing.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-10-25T23:24:05.047" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2691" PostTypeId="2" ParentId="2676" CreationDate="2014-10-26T06:23:37.097" Score="7" Body="&lt;p&gt;EDIT: see also the community wiki answer at: &lt;a href=&quot;https://opendata.stackexchange.com/questions/10154/sources-of-weather-data&quot;&gt;https://opendata.stackexchange.com/questions/10154/sources-of-weather-data&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;ftp://ftp.ncdc.noaa.gov/pub/data/noaa/isd-lite/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ftp://ftp.ncdc.noaa.gov/pub/data/noaa/isd-lite/&lt;/a&gt; includes hourly data for thousands of stations. The data includes temperature, dew point (from which you can compute relative humidity), wind speed and direction, and you can of course calculate solar position.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It doesn't, however, have all the information you seek.&lt;/p&gt;&#xA;" OwnerDisplayName="user967" LastEditorUserId="-1" LastEditDate="2017-04-13T12:57:29.940" LastActivityDate="2016-11-23T10:43:01.277" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2693" PostTypeId="1" AcceptedAnswerId="2694" CreationDate="2014-10-26T15:45:23.140" Score="11" ViewCount="8574" Body="&lt;p&gt;I have been given the following diagrams: &#xA;&lt;img src=&quot;https://i.stack.imgur.com/W2dP3.png&quot; alt=&quot;enter image description here&quot;&gt;&#xA;and &lt;img src=&quot;https://i.stack.imgur.com/58bg7.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;br&gt;&#xA;and a database that is structured like this:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;ROCK NAME |SIO2 |TIO2| AL2O3|   CR2O3|  FEOT|   CAO|    MGO|    MNO|    K2O|    NA2O|   P2O5|  &#xA;WEHRLITE    |45.42| 0.17|   2.57|   0.32|   11.3384|    7.54|   31.93|  0.17|   0.01|   0.24|   0.01|  &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;I want to know how to normalize the data and use these diagrams to identify the rock name based on the IUGS specification. I then am tasked to write a program that will do this automatically meaning that I have to come up with some semi-mathematically-based process to identify these rocks. Any ideas? &lt;/p&gt;&#xA;" OwnerUserId="1033" LastEditorUserId="1033" LastEditDate="2017-12-19T19:48:00.510" LastActivityDate="2017-12-19T19:48:00.510" Title="How do you use the streckeisen (QAPF) classification ternary diagram to identify igneous rocks based on chemical rock composition?" Tags="|mineralogy|petrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2694" PostTypeId="2" ParentId="2693" CreationDate="2014-10-26T19:19:37.793" Score="12" Body="&lt;p&gt;&lt;strong&gt;Why you should not do it&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The QAPF and related diagrams are intended for classification of rocks in the field, or preliminary classification with modal proportions as seen in the optical microscope. They are not designed with the chemical composition of the rocks in the mind. Furthermore, these diagrams are merely descriptive and not genetic. They do not take into account many factors affecting the various characteristics of the rocks. While doing something like this may be interesting for homework exercise, it is not something I would expect to see in a recent research article.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;If you want to do it anyway&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your solution should consist of two steps.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Finding what is the norm of the rock. A norm is an estimation of the ideal mineralogy of an igneous rock, based on the chemical composition of the rock. The most common norm calculation method is the CIPW norm, but there are other methods as well. For starters you should do fine with the norm. Instructions on how to calculate the CIPW norm are available in your favourite petrology textbook, &lt;a href=&quot;http://www.uwgb.edu/dutchs/Petrology/cipw01.htm&quot;&gt;here&lt;/a&gt;, or &lt;a href=&quot;http://minerva.union.edu/hollochk/c_petrology/norms.htm&quot;&gt;here&lt;/a&gt;. I've also seen some algorithms that do it for you, but their success varies on the silica undersaturated side of the rock spectrum.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Now that you have the norm, add together anorthite and albite to count how much plagioclase you have. You are also given the rest of the minerals. Now all you need to do is use the normalised relative proportions of each triplet of minerals to place them on the diagram. &lt;a href=&quot;https://en.wikipedia.org/wiki/Ternary_plot#Example&quot;&gt;Here's a refresher on that&lt;/a&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="725" LastActivityDate="2014-10-26T19:19:37.793" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2695" PostTypeId="2" ParentId="725" CreationDate="2014-10-27T04:11:39.023" Score="6" Body="&lt;p&gt;The seismometer records the time when the P and S-waves arrive at the recording station. P-waves travel faster through the earth than S-waves and so they arrive at the seismometer station before the S-waves and are recorded by the seismometer first. The difference in arrival time between the two types of seismic wave can be used to calculate the distance of the earthquake's epicenter from the seismometer, as the further away an earthquake is, the greater the lag time between the detection of the S waves relative to the P waves.&lt;/p&gt;&#xA;" OwnerUserId="1036" LastEditorUserId="115" LastEditDate="2014-10-31T21:20:09.953" LastActivityDate="2014-10-31T21:20:09.953" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2696" PostTypeId="1" CreationDate="2014-10-27T07:31:21.090" Score="4" ViewCount="83" Body="&lt;p&gt;How do hybrid cars reduce carbon emissions (wouldn't they just transfer fuel emissions to electricity consumption?)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Doing an accounting project on upgrading fuel supplied  cars to hybrids and we're spending a lot of money to set up charging stations. But i got to thinking wouldn't the fuel save just transfer into energy consumed?&lt;/p&gt;&#xA;" OwnerUserId="1037" LastActivityDate="2014-10-27T07:31:21.090" Title="How do hybrid cars reduce carbon emissions (wouldn't they just transfer fuel emissions to electricity consumption?)" Tags="|environmental-protection|" AnswerCount="0" CommentCount="4" ClosedDate="2014-10-27T15:04:53.533" ContentLicense="CC BY-SA 3.0" />
  <row Id="2698" PostTypeId="1" AcceptedAnswerId="2703" CreationDate="2014-10-27T18:23:08.843" Score="15" ViewCount="12422" Body="&lt;p&gt;I'm having trouble grasping which properties of the soil are described by hydraulic diffusivity (sometimes referred to as soil-moisture diffusivity which is based on the &lt;a href=&quot;http://en.wikipedia.org/wiki/Groundwater_flow_equation#Diffusion_equation_.28transient_flow.29&quot;&gt;diffusion equation&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What does hydraulic diffusivity describe and how is it related to hydraulic conductivity?  &lt;/p&gt;&#xA;" OwnerUserId="580" LastActivityDate="2019-05-28T13:35:13.150" Title="What is hydraulic diffusivity?" Tags="|hydrology|soil|soil-moisture|" AnswerCount="1" CommentCount="3" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2700" PostTypeId="2" ParentId="2452" CreationDate="2014-10-28T13:15:44.317" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Are there papers or datasets of average CO&lt;sub&gt;2&lt;/sub&gt; concentrations down at&#xA;  ground level (say 0-20 metres upwards from the ground), in the spaces&#xA;  between buildings - streets, parks and so on?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes, &lt;a href=&quot;http://www.tandfonline.com/doi/abs/10.1080/02723646.1998.10642642#preview&quot; rel=&quot;nofollow&quot;&gt;THE URBAN CO2 DOME OF PHOENIX, ARIZONA&lt;/a&gt; has measurements at a height of 2 meters above ground level, 1.6 km horizontal resolution. CO&lt;sub&gt;2&lt;/sub&gt; concentrations are 555 ppm near the center of the city.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S135223100000412X&quot; rel=&quot;nofollow&quot;&gt;An intensive two-week study of an urban CO&lt;sub&gt;2&lt;/sub&gt; dome in Phoenix, Arizona, USA&lt;/a&gt; has higher resolution data along selected transects.&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="725" LastEditDate="2014-12-13T08:22:29.243" LastActivityDate="2014-12-13T08:22:29.243" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2701" PostTypeId="1" AcceptedAnswerId="2702" CreationDate="2014-10-28T20:30:27.313" Score="8" ViewCount="631" Body="&lt;p&gt;The North and South Bismarck microplates (north east of Papua New Guinea) are separated by a ridge of sea floor spreading, as described in &lt;a href=&quot;http://volcano.oregonstate.edu/book/export/html/139&quot; rel=&quot;noreferrer&quot;&gt;Oregon State webpage&lt;/a&gt; as&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The tectonics in this part of the world is very complicated. A spreading center creates the North and South Bismarck microplates. The Pacific plate is subducted under the North Bismarck Plate. The Solomon Sea microplate is subducted under the South Bismarck microplate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And shown in the diagram below (from the same source):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/XIMqp.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What are the geological mechanisms that cause this area of sea floor spreading in an area dominated by subduction processes?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="32" LastEditDate="2014-10-28T21:20:06.487" LastActivityDate="2014-10-28T22:15:42.850" Title="What are the geological mechanisms for sea floor spreading in the Bismarck Sea?" Tags="|plate-tectonics|geodynamics|subduction|sea-floor-spreading|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2702" PostTypeId="2" ParentId="2701" CreationDate="2014-10-28T22:15:42.850" Score="4" Body="&lt;p&gt;Ah yes, this is a very good question. The formation of back-arc spreading centers is an open research problem, and happens to be the main topic of my office mate's dissertation! While these aren't exactly &quot;clean&quot; back-arcs, the formation of them is similar, I'm fairly sure. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The formation of back-arcs is caused by &quot;Trench Roll-back&quot;. Trench Rollback is where the trench is pushed back in the opposite direction of the subducting slab and causes extension in the back-arc, forming a spreading center.  Below is a diagram from &lt;em&gt;Modeling the dynamics of Subducting Slabs&lt;/em&gt;, Magali Billen, Annual Reviews of Earth and Planetary Sciences, 2008:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/5FroB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can ignore the &quot;Shallow&quot; vs &quot;Deep and Wide Box&quot; comparisons, those only matter for building a modeling domain. What is important is noticing what happens to the slab when it hits the 660km boundary: it has a much more difficult time subducting. The slab &quot;glides&quot; through the upper mantle, but deeper in the earth, the mineralogical phase changes make the mantle much denser, creating a much stronger normal force on the slab. This normal force transfers energy into the slab and &quot;pushes&quot; back causing a drag between the deeper slab and the slab in the upper mantle. Since the under-riding plate and the overriding plate are weakly coupled viscously, only a small portion of the overriding plate is pulled with the trench. This causes extension/rifting. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not all subduction zones have a back arc: weaker slabs tend to have a much harder time forming one as the transfer of energy in a strong slab is much more efficient. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is also important to note that these phase changes are currently the leading theory, but our dynamic models have a hard time dynamically developing trench rollback. Sure, the literature might sound optimistic about it, but thats with surface kinematic boundary conditions and not pure dynamics. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These rifting centers form from trench roll-back. We can measure this roll-back with GPS. What causes trench roll-back is a much harder question to answer, in my opinion.&lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-10-28T22:15:42.850" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2703" PostTypeId="2" ParentId="2698" CreationDate="2014-10-29T14:30:56.260" Score="11" Body="&lt;p&gt;So let's get through some definitions. I will not discuss the derivations of this, but you can look this up, if you want to in the source I provided.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We find ourselves in a porous medium, so we will have always some volume filling factor $\Theta$ of water in rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/ogCB9.png&quot; alt=&quot;enter image description here&quot;&gt; (copyright K. Roth, Heidelberg University)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then we can start with the &lt;strong&gt;hydraulic conductivity&lt;/strong&gt;, that can be defined as $$K = \frac{\Theta \left&amp;lt; \kappa \nabla P \right&amp;gt;}{\mu}$$&#xA;Here we have quite some notation to clarify:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$\Theta$ is the local filling fraction of water in an aquifer&lt;/li&gt;&#xA;&lt;li&gt;$\mu$ is the molecular diffusivity&lt;/li&gt;&#xA;&lt;li&gt;The brackets $\left&amp;lt; ... \right&amp;gt;$ denote the macroscopic average over the microscopic aquifer structure that is given by Permeability $\kappa$ and local pressure gradient.&#xA;The Permeability itself is a way to encapsulate how easy water can flow through a given geometry.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;This is the most rigorous definition I could find in my notes. The lecture however is unavailable on the internet, so you'll have to take my word for this. I just mention this as I don't know whether you're more interested on the theoretical side, or the pragmatic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The pragmatic approach is usually to simply state Darcy's law $$ q = - K \frac{dh}{dz} $$&#xA;relating the water mass flux $q = \rho v$ to the gradient of hydraulic head.&#xA;We see now that a flow velocity will result from a pressure gradient, but strongly modified through the microscopic properties encapsulated in K.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The &lt;strong&gt;hydraulic diffusivity&lt;/strong&gt; you search for is then written as $$D = \frac{K}{S}$$ where S is the water storage fraction, with $S \sim \Theta$ (not strictly correct). So in a way this just cancels the $\Theta$ in $K$ and appears in the pressure diffusion equation:&#xA;$$ \partial_t P = D \Delta P $$&#xA;and therefore D gives the local diffusion speed of pressure disturbances (which is interestingly not the speed of sound $c_s$ in aquifers!)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We could now say, for educatory purposes that the difference between $K$ and $D$ is only $\Theta$. This makes sense when we look at the context where those two parameters appear:&#xA;$K$ gives the strength of mass-flow for the fluid, the better filled the volume is, the more mass will flow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pressure, however does not care for the amount of water that flows, as it exists everywhere where water is sitting at a given moment, so the coefficient for its propagation does not depend on the filling of volume.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can look up the derivations for example &lt;a href=&quot;http://www.iup.uni-heidelberg.de/institut/studium/lehre/AquaPhys/docMVEnv3_12/MVEnv3_2012_V7.pdf&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&#xA;Tell me in the comments, if anything is unclear.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2014-10-29T14:30:56.260" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2704" PostTypeId="1" AcceptedAnswerId="2705" CreationDate="2014-10-29T18:45:41.913" Score="14" ViewCount="724" Body="&lt;p&gt;Have there been any instances where seismologists have successfully predicted the occurrence of earthquakes?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If so, then why has the number of scientists working on this area has declined (as compared to topics like Hazard Assessment) ?&lt;/p&gt;&#xA;" OwnerUserId="594" LastEditorDisplayName="user889" LastEditDate="2014-10-30T00:13:22.930" LastActivityDate="2014-10-30T00:13:22.930" Title="Successful Earthquake predictions" Tags="|geophysics|seismology|earthquakes|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2705" PostTypeId="2" ParentId="2704" CreationDate="2014-10-29T18:58:12.910" Score="12" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/1975_Haicheng_earthquake&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Haicheng Earthquake&lt;/a&gt; is the only successful evacuation of a devastating earthquakes. It's notable that the Chinese scientists thought they had figured out ot predict earthquakes, but have subsequently failed to predict many catastrophic earthquakes and many people's lives have been ended, ruined, changed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is news to me that this research is in decline, but there has been recent &lt;a href=&quot;http://worldnews.nbcnews.com/_news/2012/10/22/14611225-scientists-found-guilty-of-manslaughter-for-failing-to-predict-italy-quake?lite&quot; rel=&quot;nofollow noreferrer&quot;&gt;scrutiny&lt;/a&gt; for failing to predict earthquakes. This type of research is very hard, and probably not answerable, here is a related question:&lt;a href=&quot;https://earthscience.stackexchange.com/questions/878/is-earthquake-prediction-possible?rq=1&quot;&gt;Is earthquake prediction possible?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hazard assessment is much easier because we can model many different types of known earthquakes and infer the damage from that. There aren't as many unknowns, it seems, for what happens after an earthquake as there is during the buildup. Plate Tectonics is complex as we live in on a dynamic planet. &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-10-29T18:58:12.910" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2706" PostTypeId="1" CreationDate="2014-10-30T05:47:53.083" Score="13" ViewCount="398" Body="&lt;p&gt;I'm trying to find an optimized spatial interpolation method that deals with fixed-location sample data points. Say if I have fixed-location sampling sites and collect data daily, and then use these data to create interpolation surfaces. Is there a method that pre-process the spatial relationships among those sampling sites and then integrate this spatial relationship into the interpolation method to speed up the whole interpolation process? I googled some information but couldn't find what I want. Can anyone put me on the right direction? Thanks.&lt;/p&gt;&#xA;" OwnerUserId="1043" LastEditorUserId="1043" LastEditDate="2014-10-30T06:11:06.120" LastActivityDate="2015-03-20T11:08:47.587" Title="Optimized interpolation method with fixed-location sample data points?" Tags="|geospatial|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2707" PostTypeId="2" ParentId="2676" CreationDate="2014-10-31T02:29:47.210" Score="4" Body="&lt;p&gt;It will take effort and programming knowledge to get data from Chilbolton Observatory, Hampshire, England, one of the few cloud research sites in the world. &lt;a href=&quot;http://www.stfc.ac.uk/chilbolton/default.aspx&quot; rel=&quot;nofollow&quot;&gt;http://www.stfc.ac.uk/chilbolton/default.aspx&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get data you need to create an account at BADC and stick to the few terms and conditions. &lt;a href=&quot;https://badc.nerc.ac.uk/data/&quot; rel=&quot;nofollow&quot;&gt;https://badc.nerc.ac.uk/data/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Data time resolution is logger resolution, sub 1 minute. You will have to decimate. Data is supplied as NETCDF. You get raw data, assume nothing. You will have to detect and handle any missing data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think you also need to understand the instruments. (in this case you will need to know and ignore some things which are widely stated and wrong)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Full up and down from direct, indirect and &quot;nocturnal&quot;. &#xA;Wind data, yes.&#xA;Temperature and simple humidity, yes.&#xA;Exotics, yes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think reality is going to strike, perhaps you need to consider what you are really trying to do. If you put in the effort I think you will reach few definite conclusions above what you can learn from a lot of reading. The gain is a working understanding of reality.&lt;/p&gt;&#xA;" OwnerUserId="1047" LastActivityDate="2014-10-31T02:29:47.210" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2709" PostTypeId="2" ParentId="2631" CreationDate="2014-10-31T19:51:02.463" Score="8" Body="&lt;p&gt;Aside from the three requirements already mentioned, electrically conductive fluid, rotation of the planet and convection of the fluid, the main additional requirement is a seed magnetic field.  There must be an initial magnetic field for the dynamo to start.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;See the following reference for more information: &lt;a href=&quot;http://astro.berkeley.edu/~gmarcy/astro160/papers/Magnetic_dynamos_physics.pdf&quot;&gt;http://astro.berkeley.edu/~gmarcy/astro160/papers/Magnetic_dynamos_physics.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2014-10-31T19:51:02.463" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2710" PostTypeId="2" ParentId="2439" CreationDate="2014-11-01T10:52:00.213" Score="14" Body="&lt;p&gt;To answer your question to the point: we don't know at all.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For most of living organisms, the fossil record is either inexistent or very fragmentary. Even estimating the number of species (which is somewhat less difficult since you need only one specimen of each species to have access to that information) is very difficult and affected by many, many biases (see the works of Jack Sepkoski, David Raup and John Alroy for instance, to see the difficulty of estimating past biodiversity). Attempts at reconstructing marine &quot;invertebrates&quot; diversity (&lt;strong&gt;Sepkoski 1978; Alroy et al. 2001, 2008&lt;/strong&gt;) showed an increase during the Phanerozoic (so, give or take, the last half-billion years), with five main mass extinction events (End Ordovician, Late Devonian, Permian/Triassic boundary, Triassic/Jurassic boundary and Cretaceous/Paleogene boundary).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The general assumption is that biomass increases when diversity increase. There is frankly not very strong basis for this assumption but that's basically all we can work with.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some living organisms however have a much better fossil record: diatoms, radiolarians, foraminifera and calcareous nannofossils (mainly from the algae group of the Haptophyta) constitutes the bulk of marine sediments and are therefore recorded consistently and abundantly. Their Cenozoic record (i. e. the last 66 Myr) in particular is remarkably complete, but still in some cases biased enough to prevent us for estimating reasonably changes in their abundance.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a matter of fact, my current research revolves around the changes in diatom abundance in sediments during the last 50 Myrs (&lt;strong&gt;Renaudie 2016&lt;/strong&gt;). Without going too much into the details, it seems, in that case, that their abundance (in sediments at least) and their diversity are more or loss synced. The interest of diatoms, in regard to your specific question, is that, today, there are one of the two main oceanic primary producers (along with Haptophyta), oceanic production itself being more or less half of the global production (see &lt;a href=&quot;https://earthscience.stackexchange.com/a/137/87&quot;&gt;this previous answer of mine&lt;/a&gt;). Their abundance increased significantly at the Eocene/Oligocene boundary and then during the Mid-Miocene. Of course it is possible that in the mean time other phytoplankton (Haptophyta, Dinoflagellates, or others) abundance might have dropped but what makes us think that this is not the case is that changes in diatom abundances during the Cenozoic match changes in atmospheric $p\mathrm{CO}_2$ (&lt;strong&gt;Beerling &amp;amp; Royer 2011&lt;/strong&gt;), implying a global increase in the net primary production.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;References:&lt;br&gt;&#xA;Alroy, J. &lt;em&gt;et al.&lt;/em&gt;, 2001. &lt;a href=&quot;http://www.pnas.org/cgi/doi/10.1073/pnas.111144698&quot; rel=&quot;noreferrer&quot;&gt;Effects of sampling standardization on estimates of Phanerozoic marine diversification.&lt;/a&gt; PNAS, 98(11): 6261-6266.&lt;br&gt;&#xA;Alroy, J. &lt;em&gt;et al.&lt;/em&gt;, 2008. &lt;a href=&quot;http://dx.doi.org/10.1126/science.1156963&quot; rel=&quot;noreferrer&quot;&gt;Phanerozoic Trends in the Global Diversity of&#xA;Marine Invertebrates&lt;/a&gt;. Science, 321: 97-100.&lt;br&gt;&#xA;Beerling, D. J. &amp;amp; Royer, D. L. 2011. &lt;a href=&quot;http://dx.doi.org/10.1038/ngeo1186&quot; rel=&quot;noreferrer&quot;&gt;Convergent Cenozoic CO2 history&lt;/a&gt;. Nature Geosciences, 4: 418-420.&lt;br&gt;&#xA;Renaudie, J. 2016. &lt;a href=&quot;https://doi.org/10.5194/bg-13-6003-2016&quot; rel=&quot;noreferrer&quot;&gt;Quantifying the Cenozoic marine diatom deposition history: links to the C and Si cycles&lt;/a&gt;. Biogeosciences, 13: 6003-6014. &lt;em&gt;[Disclaimer: I am the author of this article]&lt;/em&gt;&lt;br&gt;&#xA;Sepkoski J. J. Jr, 1978. &lt;a href=&quot;http://www.jstor.org/stable/2400203&quot; rel=&quot;noreferrer&quot;&gt;A kinetic model of Phanerozoic taxonomic diversity I. Analysis of marine orders.&lt;/a&gt; Paleobiology, 4: 223-251.&lt;br&gt;&#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2017-09-19T08:07:51.250" LastActivityDate="2017-09-19T08:07:51.250" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2711" PostTypeId="1" AcceptedAnswerId="2712" CreationDate="2014-11-01T14:32:05.683" Score="9" ViewCount="1313" Body="&lt;p&gt;After recently visiting the Dead Sea in Israel and not getting any skin burns, I was wondering about the reasons for that. Searching the literature, it seems that the UV radiation is indeed lower in the Dead Sea (&lt;em&gt;ca&lt;/em&gt;. -400 m) compared to Beer Sheva (a nearby city at &lt;em&gt;ca&lt;/em&gt;. +300 m): &lt;a href=&quot;http://solarlight.com/wp-content/uploads/2013/04/IJC1997.pdf&quot;&gt;1&lt;/a&gt; &lt;a href=&quot;http://revistas.ucm.es/index.php/ANHM/issue/view/2251/showToc&quot;&gt;2&lt;/a&gt; &lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pubmed/1158663&quot;&gt;3&lt;/a&gt;. Both UVA and UVB rays are lower, but UVB rays are attenuated the most.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These sources give mostly measurements, but hardly discuss the reasons for the lower radiation. I always thought that the ozone layer blocks most of the UV radiation, but here it seems that just a few hundred meters of atmosphere can greatly reduce the amount of incident UV.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the reasons for that? Is it simply because there are more air molecules that absorb the radiation?&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2014-11-02T05:45:52.270" Title="What are the causes of lower UV radiation at lower elevations?" Tags="|atmosphere|ozone|topography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2712" PostTypeId="2" ParentId="2711" CreationDate="2014-11-01T22:17:19.450" Score="8" Body="&lt;p&gt;You are almost totally correct when you asked:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What are the reasons for that? &lt;strong&gt;Is it simply because there are more air molecules that absorb the radiation&lt;/strong&gt;?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The Ozone Layer blocks most of UVB, but does not affect the amount UVA entering the atmosphere (as seen in the illustration below):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Tq3v0.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://en.wikipedia.org/wiki/Ultraviolet&quot; rel=&quot;noreferrer&quot;&gt;Image source&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But there is a little more to it than that. From NASA's Earth Observatory's webpage &lt;a href=&quot;http://earthobservatory.nasa.gov/Features/UVB/uvb_radiation3.php&quot; rel=&quot;noreferrer&quot;&gt;What Determines How Much Ultraviolet Radiation Reaches the Earth’s Surface?&lt;/a&gt;, elevation's role in attenuating UVB (and by similar processes, UVA):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;high elevations UV-B radiation travels through less atmosphere before it reaches the ground, and so it has fewer chances of encountering radiation-absorbing aerosols or chemical substances (such as ozone and sulfur dioxide) than it does at lower elevations.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The aerosols absorb and scatter incident UV radiation.  So nearer to the surface, there is a greater concentration that the light must pass through - and as the altitude decreases, the UV radiation path is therefore increased, so the further 'down' in altitude, the more the air mass and an increased presence of aerosols absorb and scatter solar UV radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In respect to the aerosols in area you have specified (the Dead Sea), according to the first link in your question, &lt;a href=&quot;http://solarlight.com/wp-content/uploads/2013/04/IJC1997.pdf&quot; rel=&quot;noreferrer&quot;&gt;The Analysis of the Ultraviolet Radiation in the Dead Sea Basin, Israel&lt;/a&gt; (Kudish et al. 1997), they state &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the air above the Dead Sea is characterized by a&#xA;  relatively high aerosol content due to the very high salt content of the Dead Sea&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Their results indicate that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The relative attenuation in the ultraviolet range as a function of wavelength, i.e.&#xA;  site-specific spectral selectivity, decreases with increasing wavelength.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;thus, indicating that the attenuation is also wavelength dependent.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-11-02T05:45:52.270" LastActivityDate="2014-11-02T05:45:52.270" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="2713" PostTypeId="1" CreationDate="2014-11-02T01:04:38.333" Score="9" ViewCount="114" Body="&lt;p&gt;I need a large dataset of the oxide components of peridotitic rocks and their manual classification for a project of mine. The only one that I managed to find was from the EarthChem database and it is too small, having only around 1700 useable samples. Does anyone have an idea of where I can find a larger dataset (&gt;10,000 samples)?&lt;/p&gt;&#xA;" OwnerUserId="1033" LastEditorUserId="1033" LastEditDate="2014-11-02T01:21:28.367" LastActivityDate="2014-11-02T01:21:28.367" Title="How can I find a large petrology dataset?" Tags="|petrology|open-data|database|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2715" PostTypeId="1" AcceptedAnswerId="2720" CreationDate="2014-11-02T21:54:33.640" Score="27" ViewCount="16120" Body="&lt;p&gt;Comparing the atmospheric compositions of Earth with our nearest neighbours:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Nvgkw.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the table shows, the Earth's atmospheric nitrogen concentration is 78%, compared to 3.8% for Venus and 2.7% for Mars &lt;a href=&quot;https://www.ucar.edu/learn/1_1_2_1t.htm&quot; rel=&quot;noreferrer&quot;&gt;Image source&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have read the excellent question and answer &lt;a href=&quot;https://earthscience.stackexchange.com/questions/874/why-do-earth-and-venus-have-different-atmospheres&quot;&gt;Why do Earth and Venus have different atmospheres?&lt;/a&gt;, but the answer focuses on the $\ce{CO2}$ content of the planets, this question is about the $\ce{N2}$ content. Also, have read &lt;a href=&quot;https://earthscience.stackexchange.com/q/2173/889&quot;&gt;Why do some planets have lots of $\ce{N2}$ and others none?&lt;/a&gt;, but in this question, I am looking at how nitrogen concentrations dominated over the other chemicals in Earth's atmosphere, not looking at similarities between planetary processes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In modern Earth, the nitrogen cycle maintains nitrogen levels, however the early pre-biotic atmosphere, was believed by&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;most of the scientific community now believes that the early Earth's atmosphere was not reducing. Instead, scientists beleive the atmosphere was full of oxidants, such as $\ce{CO2}$ and $\ce{N2}$.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://people.chem.duke.edu/~jds/cruise_chem/Exobiology/PBearth.html&quot; rel=&quot;noreferrer&quot;&gt;Duke University Pre-Biotic Earth webpage&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is the origin of the dominant atmospheric nitrogen content in Earth's atmosphere?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user12525" LastEditDate="2019-04-18T13:45:11.697" LastActivityDate="2021-05-02T19:45:48.077" Title="What is the origin of the dominant atmospheric nitrogen content in Earth's atmosphere?" Tags="|atmosphere|geochemistry|earth-history|nitrogen|" AnswerCount="5" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2716" PostTypeId="1" CreationDate="2014-11-02T22:28:23.523" Score="6" ViewCount="119" Body="&lt;p&gt;Documented strange behaviors of animals before an earthquake could invite us to believe that some of them anticipate tectonic activity. We also know that human complex organization makes it difficult for all of us to get in touch with our deepest instinct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it possible that this hypothetical natural ability to anticipate earthquakes still remains as some instinctive input in our daily behavior?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If yes, and to try to measure how much global human activity could reflect some anticipation, I think we could with modern technologies, monitor all our connected device hmi's (Mouse, touchpad, keyboard, phone, voice spectral data's) (anonymously of course) and study delta's on long periods.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also want to point a risk: Is it not dangerous to do so if those anticipations are among the strongest booster of human intellect and progress in general?  (Pandora box problem)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But maybe, those hypothetical intuitions are source of evil momentum...&lt;/p&gt;&#xA;" OwnerUserId="1052" LastEditorUserId="1052" LastEditDate="2014-11-03T16:33:49.827" LastActivityDate="2014-11-04T14:31:49.553" Title="Would it be wise to monitor real time human activity to anticipate earthquakes?" Tags="|geophysics|geology|tectonics|technology|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="2717" PostTypeId="1" AcceptedAnswerId="2722" CreationDate="2014-11-03T04:08:18.750" Score="8" ViewCount="758" Body="&lt;p&gt;Reading one of my other questions, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2530/how-much-would-the-greenland-landmass-isostatic-rebound-contribute-to-long-term&quot;&gt;How much would the Greenland landmass isostatic rebound contribute to long term climate change?&lt;/a&gt;, a subsequent question is what, if any, effect the isostatic rebound after ice cap melting would have on plate tectonic movement.  A similar situation could apply to the Antarctic ice sheet.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A key consideration for this inquiry is questioning if there any evidence from the geological past to link isostatic rebound from ice sheets melting to changes in plate tectonic movement.  So, the question is,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What evidence is there linking melting ice caps and changes in tectonic movement?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="11908" LastEditDate="2019-03-13T05:17:29.933" LastActivityDate="2019-03-13T05:17:29.933" Title="What evidence is there linking melting ice caps and changes in tectonic movement?" Tags="|plate-tectonics|glaciology|ice-sheets|isostasy|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2718" PostTypeId="1" CreationDate="2014-11-03T14:17:18.607" Score="10" ViewCount="2054" Body="&lt;p&gt;I am involved in developing a weather based application which needs to calculate relative humidity and display it. I grab other weather variables like temperature, precipitation, wind speed and direction from the weather site. Is it possible to calculate relative humidity using this data?&lt;/p&gt;&#xA;" OwnerUserId="1053" LastEditorUserId="192" LastEditDate="2014-11-03T15:34:35.670" LastActivityDate="2019-03-26T04:24:00.663" Title="How to calculate relative humidity?" Tags="|meteorology|humidity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2719" PostTypeId="2" ParentId="2718" CreationDate="2014-11-03T16:49:48.663" Score="12" Body="&lt;p&gt;&lt;strong&gt;No, this is not enough.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Relative_humidity&quot;&gt;Relative humidity&lt;/a&gt; is defined as the water vapour partial pressure relative relative to the saturation water vapour pressure:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\phi  =  {{e_w} \over {{e^*}_w}}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where ${e^*}_w$ is the equilibrium vapour pressure (which may be relative to either liquid water, or to ice), and $e_w$ is the partial pressure of water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;${e^*}_w$ can be calculated using the &lt;a href=&quot;https://en.wikipedia.org/wiki/Clausius%E2%80%93Clapeyron_relation&quot;&gt;Clausius-Clapeyron relation&lt;/a&gt;, but to get $e_w$ you need &lt;em&gt;some&lt;/em&gt; information on the water content.  This information may come in many forms:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Water vapour mixing ratio (the number of water molecules per unit volume)&lt;/li&gt;&#xA;&lt;li&gt;Specific humidity (the mass of water per unit volume)&lt;/li&gt;&#xA;&lt;li&gt;Partial pressure of water vapour ($e_w$)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Dew_point&quot;&gt;Dew point&lt;/a&gt;, which is the temperature at which $e_w = e^*_w$.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The one you are most likely to find on meteorology websites is the dew point temperature.  Basically, if you have two of temperature, dew point temperature, and relative humidity, you can calculate the third.  For example, see &lt;a href=&quot;http://andrew.rsmas.miami.edu/bmcnoldy/Humidity.html&quot;&gt;this University of Miami calculator&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2014-11-03T16:54:56.323" LastActivityDate="2014-11-03T16:54:56.323" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2720" PostTypeId="2" ParentId="2715" CreationDate="2014-11-03T18:36:12.857" Score="23" Body="&lt;p&gt;According to the recent paper in Nature Geoscience: &lt;a href=&quot;http://www.nature.com/ngeo/journal/v7/n11/full/ngeo2271.html&quot;&gt;Nitrogen speciation in upper mantle fluids and the origin of Earth's nitrogen-rich atmosphere&lt;/a&gt;, $N_2$ originates from regions of the Earth where plates are converging.  Venus and Mars lack plate tectonics and therefore lack $N_2$ in their atmospheres.  In other regions of Earth upper mantle, and in Venus and Mars, nitrogen is expected to exist as aqueous ammonium and not enter the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2014-11-03T18:41:23.130" LastActivityDate="2014-11-03T18:41:23.130" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2721" PostTypeId="2" ParentId="2715" CreationDate="2014-11-03T20:17:37.513" Score="7" Body="&lt;p&gt;Nitrogen is volatile in most of its forms here on Earth. It is fairly non-reactive with most materials that make up the solid part of Earth, and it is very stable in the presence of solar radiation in the atmosphere. Even though, nitrogen is 4 times more abundant than oxygen in the atmosphere, we must also consider the relative abundances of nitrogen and oxygen over the entire Earth, where oxygen is about 10,000 times more abundant (water, sand). In life forms, nitrogen is less abundant than oxygen, mainly due to the abundance of water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Venus and Mars, though, have lots of CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere. Plant life on Earth (Ocean + Land) and precipitation have taken CO&lt;sub&gt;2&lt;/sub&gt; out of the atmosphere... plants created the oxygen reserve.  Earth is a distinctly unique planet because it undergoes hydrologic, geologic, and biological processes that take CO&lt;sub&gt;2&lt;/sub&gt; out of the atmosphere. &lt;/p&gt;&#xA;" OwnerUserId="1055" LastEditorUserId="725" LastEditDate="2014-12-18T06:55:05.607" LastActivityDate="2014-12-18T06:55:05.607" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2722" PostTypeId="2" ParentId="2717" CreationDate="2014-11-03T20:49:49.907" Score="4" Body="&lt;p&gt;Continents move &lt;em&gt;slowly&lt;/em&gt;. Glaciations are ephemeral in comparison.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, there apparently is a huge connection between plate tectonics and whether the Earth is in icehouse or hothouse conditions. There was very little if any ice on the Earth when the Earth was in hothouse (aka greenhouse) conditions. Dinosaurs roamed close to the poles. The Earth's climate was (and is) considerably cooler during icehouse Earth conditions. Widespread glaciation has only occurred during icehouse Earth conditions. Note that we are currently under icehouse Earth conditions; we just happen to be between glaciations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following conditions that contribute to icehouse Earth are all due to plate tectonics:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Having a continent parked over a pole.&lt;br&gt;&#xA;For example, Antarctica is currently parked over the South Pole. This is not a sufficient condition, however. Antarctica has been parked over the South Pole for 100 million years or so. The Earth has been in icehouse conditions for the last 30 million or so years, and in ice age conditions for about the last 2.3 million years.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Having significant land masses within 45 degrees of a pole.&lt;br&gt;&#xA;With the possible exception of snowball Earth (icehouse Earth gone wild), icehouse conditions need significant amounts of land near a pole. Having one continent parked over the pole but most of the continents close to the equator doesn't create icehouse conditions.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Having relatively low seafloor spreading at midoceanic ridges.&lt;br&gt;&#xA;This is crucial, for two reasons. Lots of seafloor spreading means lots of CO&lt;sub&gt;2&lt;/sub&gt; being released into the oceans and eventually into the atmosphere, thereby enhancing the greenhouse effect. Lots of seafloor spreading also means more and higher midoceanic ridges. This raises the sea level, which in turn increases the amount of Earth's surface covered by water, which in turn decreases the Earth's albedo. Reduced seafloor spreading means reduced CO&lt;sub&gt;2&lt;/sub&gt; levels, reduced sea level, and increased albedo.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Having oceanic currents keep equatorial regions warm, polar regions cool.&lt;br&gt;&#xA;The opening of the Drake Passage about 41 million years ago and the opening of the Tasmanian Gateway about 35 million years ago enabled the cold circum-Antarctic current to form. This is when Antarctica turned from just cold to &amp;lt; expletive deleted &gt; cold. The closure of the Panama seaway between 13 and 2.6 million years was the last nail in the coffin regarding current ice age (as opposed to mere icehouse) conditions.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-11-03T20:49:49.907" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2723" PostTypeId="1" CreationDate="2014-11-04T05:41:15.627" Score="11" ViewCount="280" Body="&lt;p&gt;Are measurements for clarity (secchi disk) or turbidity (nephelometer) made for water quality related in any way to measurements made for optical or aerosol optical depth in meteorology?&lt;/p&gt;&#xA;" OwnerUserId="1057" LastActivityDate="2014-11-07T06:11:14.917" Title="Turbidity/clarity vs optical depth" Tags="|measurements|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2724" PostTypeId="1" CreationDate="2014-11-04T10:19:32.063" Score="11" ViewCount="597" Body="&lt;p&gt;The recent lava flows from the current eruption from the Kilauea volcano in Hawaii have generated a considerable amount of interest and concern for property.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the article &lt;a href=&quot;http://www.usatoday.com/story/news/nation/2014/10/30/hawaii-lava-flow/18196311/&quot; rel=&quot;nofollow noreferrer&quot;&gt;slow-motion disaster as lava nears main Hawaiian road&lt;/a&gt;, USA Today suggests that the variable speed of the lava flow has caused considerable concern and uncertainty:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;It's like slow torture,&quot; said Paul Utes, who owns the Black Rock Cafe in Pahoa. &quot;It speeds up, it slows down, it speeds up, it slows down. It's not like any other event where it comes and goes ... and you can move on.&quot;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Predicting the future speed of the lava flow simply isn't possible,&#xA;  geologists say, because the advance rate is extremely variable and&#xA;  depends on how much lava the volcano produces.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Despite that evasion, it seems there must be more to the story...&lt;br&gt;&#xA;&lt;strong&gt;What geological processes affect lava flow speed from the Kilauea volcano?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="6298" LastEditorDisplayName="user889" LastEditDate="2017-02-10T10:47:22.517" LastActivityDate="2017-02-17T03:22:22.153" Title="What geological processes affect the speed of Kilauea lava flows?" Tags="|volcanology|volcanic-hazard|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2725" PostTypeId="2" ParentId="2716" CreationDate="2014-11-04T14:31:49.553" Score="5" Body="&lt;p&gt;If you have no prior information that event B depends on event A, it's a logical error to claim event A causes event B just because you find they are correlated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's say you collect a large data set of how people use their computer-mouse, and show that there is some change in a statistic of this data preceding an earthquake. That cannot not prove that the anticipation of an earthquake is causing people to behave differently, because the data will always correlate just as well with some other unrelated event C (such as a swing in the stock-market.)&lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-11-04T14:31:49.553" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2726" PostTypeId="1" AcceptedAnswerId="2731" CreationDate="2014-11-04T21:17:41.207" Score="5" ViewCount="451" Body="&lt;p&gt;If a parcel of air ascends adiabatically, would condensation be reached at the lifting condensation level (LCL) or the level of free condensation (LFC)? &lt;/p&gt;&#xA;" OwnerUserId="920" LastEditorUserId="124" LastEditDate="2014-11-05T07:36:03.213" LastActivityDate="2014-11-07T05:50:09.227" Title="Pressure of condensation of an air parcel" Tags="|meteorology|atmosphere|thermodynamics|radiosounding|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2727" PostTypeId="1" CreationDate="2014-11-04T22:14:36.540" Score="17" ViewCount="3668" Body="&lt;p&gt;If I had the choice to move to an arbitrary region on the planet, which regions should I favour and which should I avoid in terms of habitability in face of the possibility of an extreme climate change?&lt;/p&gt;&#xA;" OwnerUserId="1062" LastEditorUserId="543" LastEditDate="2015-12-01T08:23:03.043" LastActivityDate="2017-04-12T04:35:55.603" Title="Which places on Earth would be affected the least by severe climate change?" Tags="|climate-change|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="2730" PostTypeId="1" AcceptedAnswerId="2743" CreationDate="2014-11-05T04:30:11.560" Score="8" ViewCount="3297" Body="&lt;p&gt;Measuring dip angle of a bed, I choose any 2 contour lines that cross the bed, and then project  lines off and measure the angle (I'm assuming this is standard technique that doesn't require explanation)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Kxfga.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But it seems (at least with my real world map) that the dip angles vary greatly depending on the contours I pick, so how should I choose which contours to pick?&lt;/p&gt;&#xA;" OwnerUserId="1065" LastActivityDate="2014-11-06T12:02:07.130" Title="Measuring bed dip angle from contour lines, which lines to pick?" Tags="|geology|structural-geology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2731" PostTypeId="2" ParentId="2726" CreationDate="2014-11-05T04:32:39.000" Score="6" Body="&lt;p&gt;The lifting condensation level (LCL) is the level at which a rising particle reaches 100 % relative humidity by adiabatic cooling.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please have a look at Wikipedia: &lt;a href=&quot;http://en.wikipedia.org/wiki/Lifted_condensation_level&quot;&gt;LCL&lt;/a&gt; and &lt;a href=&quot;http://en.wikipedia.org/wiki/Level_of_free_convection&quot;&gt;LFC (level of free convection!)&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2014-11-05T06:01:30.243" LastActivityDate="2014-11-05T06:01:30.243" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2732" PostTypeId="1" AcceptedAnswerId="2741" CreationDate="2014-11-05T07:17:54.020" Score="14" ViewCount="7555" Body="&lt;p&gt;I am using Weather Research and Forecasting model WRF and the WRF Preprocessing System WPS and could not get a satisfying answer from wrfhelp. Can anyone guide me in transforming latitude and longitude to grid points especially for nested grids? &#xA;Specifically &lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/OnLineTutorial/Basics/GEOGRID/geogrid_namelist.htm&quot;&gt;http://www2.mmm.ucar.edu/wrf/OnLineTutorial/Basics/GEOGRID/geogrid_namelist.htm&lt;/a&gt; and &lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/docs/user_guide_V3/users_guide_chap3.htm#_Description_of_the_1&quot;&gt;http://www2.mmm.ucar.edu/wrf/users/docs/user_guide_V3/users_guide_chap3.htm#_Description_of_the_1&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How does one transform latitude and longitude to &lt;code&gt;i_parent_start&lt;/code&gt; and &lt;code&gt;j_parent_start&lt;/code&gt;? How is this related to &lt;code&gt;dx&lt;/code&gt; and &lt;code&gt;dy&lt;/code&gt; and &lt;code&gt;ref_lat&lt;/code&gt; and &lt;code&gt;ref_lon&lt;/code&gt;? A simple example and an explanation would be very helpful. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorUserId="192" LastEditDate="2014-11-06T05:36:52.360" LastActivityDate="2015-02-15T17:11:02.783" Title="How to get cell indices from latitude and longitude in WRF model grids?" Tags="|meteorology|models|numerical-modelling|wrf|" AnswerCount="4" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2733" PostTypeId="1" CreationDate="2014-11-05T07:23:47.667" Score="7" ViewCount="230" Body="&lt;p&gt;Yesterday morning (04.11.2014) I woke up at 6:40 as usual and noticed that it was relatively bright out. I had a better look around 7 and concluded that it was definitely quite a bit brighter than it was the day before at that time. There was also a strange, yellow tint to the light.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I looked up &lt;a href=&quot;http://www.timeanddate.com/sun/switzerland/basel&quot; rel=&quot;nofollow&quot;&gt;when the sun comes up in Basel&lt;/a&gt; (where I live) and found out it's at 7:18. Later I did some googling to see if anyone else had noticed this and came across &lt;a href=&quot;http://atmospherical.blogspot.ch/2008/02/unusually-bright-twilights-over-western.html&quot; rel=&quot;nofollow&quot;&gt;this article about something similar happening in 2008&lt;/a&gt;. It mentions &lt;a href=&quot;http://atmospherical.blogspot.ch/2008/02/unusually-bright-twilights-over-western.html&quot; rel=&quot;nofollow&quot;&gt;polar stratospheric clouds&lt;/a&gt; as a likely cause. The following evening however, I didn't notice anything remarkable. And as I write this the next morning, The sun has now been up for an hour but due to clouds it looks darker than it did an hour and a half earlier in the morning yesterday.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I'm wondering, &lt;strong&gt;what is the cause of this unusually bright morning twilight?&lt;/strong&gt; And can I expect to see it again in the coming days/weeks/months?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Something that might relate to this is the &lt;a href=&quot;http://www.washingtonpost.com/blogs/capital-weather-gang/wp/2014/10/13/fall-snow-bonanza-in-north-america-and-siberia-may-portend-brutal-winter/&quot; rel=&quot;nofollow&quot;&gt;siberian winter&lt;/a&gt; that seems to await Europe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;PS: I also wouldn't be averse to other people around Europe confirming that they also noticed this.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="1058" LastEditorDisplayName="user889" LastEditDate="2014-12-31T09:37:20.970" LastActivityDate="2015-05-04T17:23:44.683" Title="Strangely bright morning twilight over Switzerland" Tags="|meteorology|atmosphere|clouds|stratosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2734" PostTypeId="1" CreationDate="2014-11-05T13:02:27.547" Score="8" ViewCount="554" Body="&lt;p&gt;To illustrate my problem, let's say I have lattitude and longitude coordinates, such as 38.871105, -77.056042.&#xA;I want to be able to calculate the new lattitude and longitude if, say, I moved 300m eastwords, or 400m northwards, in a way that google maps will like.&#xA;Now, from what I can understand, this would mean converting it from lat/long to mercator pixel coordinates, getting new mercator pixel coordinates then converting back to lat/long...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's what Wikipedia has to say on Google's Mercator projection:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/v2EVw.png&quot; alt=&quot;Wikipedia&amp;#39;s formula&quot;&gt;&#xA;Why do the above equations not actually take into account the longitude? And what is a? If I could understand these equations then theoretically the rest should be easy...&#xA;Thanks!&#xA;-B&lt;/p&gt;&#xA;" OwnerUserId="1067" LastEditorUserId="6129" LastEditDate="2020-05-12T16:51:14.550" LastActivityDate="2020-05-12T18:36:13.233" Title="Understanding the Mercator Projection" Tags="|models|cartography|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2735" PostTypeId="2" ParentId="2734" CreationDate="2014-11-05T13:33:06.560" Score="-1" Body="&lt;p&gt;The theory or purpose behind the Web Mercator projection is to project the globe into a rectangle made up of equally sized tiles at any zoom level. It's accuracy is highly suspect for calculating area's and distance; it is used because it makes it fast and easy to cache tiles to serve imagery and other basemaps. Rather than use the formula on Wikipedia i would look up EPSG:3857 (Mercator). As for using Google maps, it lets you toggle the reference system in the viewer from decimal to lat/long.&lt;/p&gt;&#xA;" OwnerUserId="1068" LastEditorUserId="5612" LastEditDate="2018-07-24T13:06:49.243" LastActivityDate="2018-07-24T13:06:49.243" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="2737" PostTypeId="2" ParentId="2727" CreationDate="2014-11-05T17:42:38.340" Score="8" Body="&lt;p&gt;The places on Earth that have historically had the most stable climates are typically within the tropics and close to sea level/coastlines.  The tropics are not influenced as much by the rest of the Earth's weather patterns since it is more of a source of weather (e.g. the strong convective atmospheric motion that moves air away from the tropics due to the dominant solar heating).  Staying close to coastlines ensures that any rising global temperatures are moderated by the abundance of water.  Staying close to sea level ensures that you are not influenced much by changes in glacier activity nor snow-melt elevation changes.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is literature that states that tropical ecosystems are most sensitive to climate change, and that tropical areas will see climate change sooner.  However, my point is that the climate itself will be the least extreme in the tropical regions near the ocean. Furthermore, I would like to point out that climate change per se will not make most of the planet uninhabitable as the question insinuates.  As the climate changes, there will certainly be very large changes to the land-surface and ecosystems... including desertification of some areas.  However, any regions with sustainable ecosystems will be habitable, given that there is a source of fresh water large enough for the human population (which the Tropics often have, due to frequent rain... though areas dependent on snow-melt feeding rivers will suffer).  &lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2014-11-06T00:43:52.650" LastActivityDate="2014-11-06T00:43:52.650" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2738" PostTypeId="1" AcceptedAnswerId="2747" CreationDate="2014-11-05T20:31:32.700" Score="4" ViewCount="335" Body="&lt;p&gt;I'm reading Shaw's &quot;Trace Elements in Magmas&quot; and in his page 16 he writes the following:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...It is necessary to look at the relationship between $c_i$ and&#xA;  $x_i$, i.e. the weight and molar concentrations. In any phase of&#xA;  weight $W$ the weight of component $i$ is $w_i$ and if the formula&#xA;  weight of $i$ is $M_i$, then the number of gfu (gram-formula unit&#xA;  concentration) of $i$ is $n_i$, where $n_i = \frac{w_i}{M_i}$...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What does he mean when he mentions the &quot;formula weight&quot; ($M_i$) and the gfu (gram formula unit)?&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2014-11-07T09:09:04.997" Title="What are the formula weight and gram-formula unit (gfu)?" Tags="|geochemistry|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2739" PostTypeId="1" CreationDate="2014-11-05T22:53:05.850" Score="10" ViewCount="225" Body="&lt;p&gt;Is there any sort of database that provides the locations of exposures of certain geologic groups or formations?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I ask because I have read that halite occurs in the Michigan Basin, and specifically occurs in beds of the Salina Formation (Silurian) and the Detroit River Group (Devonian).  I would love to find a source (preferably a map) that provides locations where these features (or really, halite) are at or near the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks.&lt;/p&gt;&#xA;" OwnerUserId="1071" LastEditorDisplayName="user20559" LastEditDate="2021-06-01T15:56:17.910" LastActivityDate="2021-06-01T15:56:17.910" Title="Database of geological group or formation exposures?" Tags="|geology|stratigraphy|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2740" PostTypeId="2" ParentId="2732" CreationDate="2014-11-05T23:22:13.070" Score="11" Body="&lt;p&gt;This question might be better suited for GIS stack exchange... but I'll take a shot:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;dx and dy are the distance per grid cell in the projected grid units, which is part of your grid definition.  ref_lat and ref_lon are part of your projection definition.  i_parent_start and j_parent_start are the horizontal grid cell numbers of the parent grid, where your nested grid sits.  I believe WRF grids are oriented so that i,j of 0,0 are the bottom left of your grid (e.g. a typical x-y cartesian coordinate system) and the first pixel position is defined to be at the 1,1 coordinate.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to create a shapefile of the grid projection, I would personally use the Spatial Allocator Tool from UNC (&lt;a href=&quot;https://www.cmascenter.org/sa-tools/&quot; rel=&quot;noreferrer&quot;&gt;https://www.cmascenter.org/sa-tools/&lt;/a&gt;).  I believe the same tool will map points to your grid as well.  However, if you want to map things to check the results, you could use your projection definition to build a custom transformation in a GIS program, project your lat/longs, and then map everything together.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/9dqpB.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2014-11-07T16:34:35.860" LastActivityDate="2014-11-07T16:34:35.860" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2741" PostTypeId="2" ParentId="2732" CreationDate="2014-11-06T05:32:08.463" Score="16" Body="&lt;p&gt;I've been a WRF user for almost 5 years now, and contributed code to a recent public release. I am not aware that WPS (WRF Preprocessing System) has such a tool that takes in the grid and point coordinates and returns the appropriate index. However, it is very straightforward to do so yourself. Some suggest using an external library, I think that may be an overkill for such a simple task. Here is what you need to do:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Run &lt;code&gt;geogrid.exe&lt;/code&gt; to generate the parent grid. Since you don't know the exact location of the nest yet, set &lt;code&gt;max_dom = 1&lt;/code&gt; in &lt;code&gt;namelist.wps&lt;/code&gt;. This will generate a file called &lt;code&gt;geo_em.d01.nc&lt;/code&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Look at the &lt;code&gt;geo_em.d01.nc&lt;/code&gt; file to find the right indices for your child domain. &lt;code&gt;i_parent_start&lt;/code&gt; and &lt;code&gt;j_parent_start&lt;/code&gt; refer to the x and y indices on the parent grid at which the southwest corner of the child grid will be positioned. &lt;code&gt;XLONG_M&lt;/code&gt; and &lt;code&gt;XLAT_M&lt;/code&gt; are the longitude and latitude grids of the mass (pressure) points. Using a programming language of choice, find the grid cell that is closest to your desired location for the child nest corner. This is typically done by looking for the minimum value of distance between desired location and all the points on the grid. For example, in Fortran, you can do something like:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;integer :: i_parent_start,j_parent_start&#xA;integer,dimension(2) :: coords&#xA;&#xA;coords = minloc((lon0-xlong_m)**2+(lat0-xlat_m)**2)&#xA;i_parent_start = coords(1)&#xA;j_parent_start = coords(2)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;where &lt;code&gt;xlong_m&lt;/code&gt; and &lt;code&gt;xlat_m&lt;/code&gt; are 2-dimensional arrays that you read from the grid, and &lt;code&gt;lat0&lt;/code&gt; and &lt;code&gt;lon0&lt;/code&gt; are the desired coordinates of the child nest southwest corner. Similarly, if you use Python, you could do:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;import numpy as np&#xA;&#xA;j_parent_start,i_parent_start = np.unravel_index(\&#xA;    np.argmin((lon0-xlong_m)**2+(lat0-xlat_m)**2),xlon_m.shape)&#xA;&#xA;# Add one because WRF indices start from 1&#xA;i_parent_start += 1&#xA;j_parent_start += 1&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;3) Now edit &lt;code&gt;namelist.wps&lt;/code&gt; again, set the &lt;code&gt;i_parent_start&lt;/code&gt; and &lt;code&gt;j_parent_start&lt;/code&gt; to the values that you calculated in step 3, set &lt;code&gt;max_dom = 2&lt;/code&gt;, and re-run &lt;code&gt;geogrid.exe&lt;/code&gt;. The child domain file &lt;code&gt;geo_em.d02.nc&lt;/code&gt; should be created.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;4) Look at the &lt;code&gt;geo_em.d02.nc&lt;/code&gt; file. Repeat the procedure until happy with the domain location.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;About the &lt;code&gt;parent_grid_ratio&lt;/code&gt; parameter. This is an integer factor of child grid refinement relative to the parent grid. For example, if set to 3, and parent grid resolution is 12 km, the child grid resolution will be 4 km. Odd values for &lt;code&gt;parent_grid_ratio&lt;/code&gt; (3, 5, etc.) are recommended because for even values, interpolation errors arise due to the nature of Arakawa C-grid staggering. &lt;code&gt;parent_grid_ratio = 3&lt;/code&gt; is the most commonly used value, and recommended by myself.  &lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2014-11-07T13:49:16.720" LastActivityDate="2014-11-07T13:49:16.720" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2742" PostTypeId="2" ParentId="174" CreationDate="2014-11-06T11:46:30.817" Score="18" Body="&lt;p&gt;I'd like to add to Brian's answer, and also point out some inaccuracies.&lt;/p&gt;&#xA;&lt;p&gt;First of all, &lt;strong&gt;it is not true that felsic minerals have lower melting temperatures than mafic minerals&lt;/strong&gt;. Here are some melting temperatures of common minerals, sorted from high to low:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Forsterite (mafic): 1890 °C&lt;/li&gt;&#xA;&lt;li&gt;Quartz (felsic): 1713 °C&lt;/li&gt;&#xA;&lt;li&gt;Anorthite (felsic): 1553 °C&lt;/li&gt;&#xA;&lt;li&gt;Diopside (mafic): 1391 °C&lt;/li&gt;&#xA;&lt;li&gt;Fayalite (mafic): 1205 °C&lt;/li&gt;&#xA;&lt;li&gt;Sanidine (felsic): 1150 °C&lt;/li&gt;&#xA;&lt;li&gt;Albite (felsic): 1118 °C&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Note that this order differs from the order in Bowen's series. There is no problem with that, because Bowen's series describes the order of crystallisation in common magmas (as Brian correctly identified) and not the crystallisation or melting temperature of the minerals. Although these two are closely related, they are not identical.&lt;/p&gt;&#xA;&lt;p&gt;So what dictates the order of the minerals in Bowen's series? This is where it gets complicated. The melting temperatures given above only apply to pure minerals in atmospheric pressures. Cooling magmas are never in the exact composition of a pure mineral, and are rarely in atmospheric pressure. Mixing of components (&lt;em&gt;i.e.&lt;/em&gt; minerals) in a single magma will depress the crystallisation temperatures of all components, and thus the melting temperatures. Think ice on a road: you can melt it either by heating it, or by adding salt. By adding a second component (&lt;span class=&quot;math-container&quot;&gt;$\mathrm{NaCl}$&lt;/span&gt;) to the pure component (&lt;span class=&quot;math-container&quot;&gt;$\mathrm{H_2O}$&lt;/span&gt;) you are making it possible for the ice to melt at temperatures lower than 0 °C.&lt;/p&gt;&#xA;&lt;p&gt;How does it relate to crystallisation and melting temperatures? Take a look at these two diagrams:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/D12NP.jpg&quot; alt=&quot;An-Di-Fo&quot; /&gt;&lt;img src=&quot;https://i.stack.imgur.com/AVp9S.jpg&quot; alt=&quot;An-Fo-Qz&quot; /&gt;&#xA;(&lt;a href=&quot;http://serc.carleton.edu/research_education/equilibria/ternary_diagrams.html&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;These diagrams describe the order of crystallisation of minerals in a magma whose composition can be defined in terms of the three end members (Anorthite, Diopside, Forsterite, and Anorthite, Forsterite, Quartz). A &lt;em&gt;line of descent&lt;/em&gt; is a line that tracks the evolution of the crystallising minerals from a magma. Take for example a magma with equal amounts of Di and Fo and slightly less An than the rest. This magma would first crystallise only forsterite, then it will crystallise forsterite and diopside together and eventually it will crystallise all three minerals together, until there is no more liquid. This is despite the higher melting temperature of anorthite over diopside. Melting this rock would result at first in &lt;strong&gt;melting of all three minerals together&lt;/strong&gt; at 1270 °C, even though their melting temperatures in isolation vary by around 500 °C.&lt;/p&gt;&#xA;&lt;p&gt;The second diagram shows a more complex situation, where a rock with a Fo rich composition might first crystallise Fo which will then be consumed to form enstatite. A similar magma with slighly less Fo component might not even crystallise forsterite at all, but rather crystallise quartz, even though the overall composition is still Fo-rich.&lt;/p&gt;&#xA;&lt;p&gt;This subject of magma crystallisation and melting is fascinating and a short introduction is available (with many visual aids) is available here: &lt;a href=&quot;http://serc.carleton.edu/research_education/equilibria/index.htm&quot; rel=&quot;noreferrer&quot;&gt;Teaching Phase Equilibria.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-06-17T03:14:20.347" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2743" PostTypeId="2" ParentId="2730" CreationDate="2014-11-06T12:02:07.130" Score="8" Body="&lt;p&gt;You are correct by saying that the dip angles vary greatly depending on the contours that you pick. In contrast to artificial maps designed to teach basic structural geology to students (such as the one you added in your question), natural maps are rarely &quot;nice and friendly&quot; regarding dip calculation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are several reasons for this:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The dip angle may actually vary. In artificial maps, the beds are usually tabular and not folded (unless this is a folding exercise). Natural rocks are rarely exactly planar and tabular, and their thickness also varies. This can result in different dips for the top and the bottom of the bed at the same location.&lt;/li&gt;&#xA;&lt;li&gt;Maps are not usually drawn with dip calculations in mind. The contacts are based on the limited exposures available to the mapping geologist. The contacts between rock units may be obscured by vegetation, talus, soil and even houses and roads. Making a map that is dip-calculation friendly is time consuming, if possible at all.&lt;/li&gt;&#xA;&lt;li&gt;It also depends on the accuracy of the topographic contours. As you probably know, you have to take the elevation into account in these calculations. Even if the contours are accurate, the topography may be not accurate or not spaced properly. I can testify from my own experience that the topographic map that was available to me of this area:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/z8MA3.jpg&quot; alt=&quot;enter image description here&quot;&gt; seems like we are walking on a somewhat planar area without any steep slopes and only several meters of variability in elevation.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;So what are your options? Some maps already have dip measurements built into them, thanks to the detailed work of the mapping geologist. If not, some structural maps of the same area may be available from the local geological survey/society. If you insist in making your own calculations, and the bed is rather planar, you can try to use a wider area for calculation (let's say 1 km instead of 100 m). You can try to take many measurements over an area and make a histogram of the measurements, or maybe examine the spatial distribution.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2014-11-06T12:02:07.130" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2744" PostTypeId="2" ParentId="2723" CreationDate="2014-11-06T18:14:02.540" Score="8" Body="&lt;p&gt;A secchi disk is basically a measurement of optical depth, and is very similar in principle to the measurements of AOD made in meteorology.  Those measurements are quantified at a particular wavelength of light (or a few discrete wavelengths), related to the Beer-Lambert law of light extinction.  Light extinction occurs due to scattering and absorption and the total attenuation is integrated.  A nephelometer, in contrast, has it's own light source which is shining on the particles, and a detector measures the reflected light (absorption is not being measured).  The nephelometer is calibrated to measure particle density by volume of a particular type of particle, based on the reflected light signature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Nephelometer&quot;&gt;http://en.wikipedia.org/wiki/Nephelometer&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Secchi_disk&quot;&gt;http://en.wikipedia.org/wiki/Secchi_disk&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Optical_depth&quot;&gt;http://en.wikipedia.org/wiki/Optical_depth&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2014-11-07T06:11:14.917" LastActivityDate="2014-11-07T06:11:14.917" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2745" PostTypeId="1" CreationDate="2014-11-06T20:29:39.980" Score="5" ViewCount="792" Body="&lt;p&gt;The East African Rift system is described by James Wood and Alex Guth of Michigan Technological University in the Geology.com web-article &lt;a href=&quot;http://geology.com/articles/east-africa-rift.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;East Africa's Great Rift Valley: A Complex Rift System&lt;/a&gt; as being a term grouping the Ethiopian Rift and both the Western and Eastern branches of the East African Rift.  As shown in the image from the Tulane University web page &lt;a href=&quot;http://www.tulane.edu/~sanelson/Natural_Disasters/volclandforms.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Volcanic Landforms&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/0oFoE.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The soon-to-be-plates either side of the rift have been named the Nubian (west) and Somali (east) by many authors (as per the Wood and Guth article linked above).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The southern extent seems to lead offshore near Madagascar, which leads me to the question, &lt;strong&gt;what evidence is there to delineate where a southern extension of the East African Rift 'plate boundary' is developing?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="725" LastEditDate="2016-08-19T11:17:50.880" LastActivityDate="2016-08-19T11:17:50.880" Title="Is there evidence to delineate where a southern extension of the East African Rift 'plate boundary' is developing?" Tags="|geophysics|plate-tectonics|east-africa-rift|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2746" PostTypeId="2" ParentId="2726" CreationDate="2014-11-07T05:50:09.227" Score="4" Body="&lt;p&gt;The LCL is the &quot;lifted&quot; level at which mechanical lifting mechanisms (frontal/dynamic or orographic) must raise a parcel to reach its dew point temperature, 100% relative humidity or saturation by adiabatic cooling. Alternatively, when a parcel of air is lifted due to heating from below, the parcel must rise to the convective condensation level (CCL) to reach saturation. (lifting due to buoyancy)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Convective_condensation_level&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/Convective_condensation_level&lt;/a&gt; &#xA;&lt;a href=&quot;http://en.wikipedia.org/wiki/Lifted_condensation_level&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/Lifted_condensation_level&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1057" LastActivityDate="2014-11-07T05:50:09.227" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2747" PostTypeId="2" ParentId="2738" CreationDate="2014-11-07T09:09:04.997" Score="6" Body="&lt;p&gt;$M_i$ is the molar mass of the &lt;em&gt;i&lt;sup&gt;th&lt;/sup&gt;&lt;/em&gt; element. Dividing $w_i$ by $M_i$ yields the number of moles of that element in the sample.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two primary ways of looking at abundances. One is by weight (or mass), the other is by number of atoms. Consider beryllium and uranium. Their abundances are very similar when looked at in terms of mass: 1.9 parts per million (ppm) for beryllium versus 1.8 ppm for uranium. In terms of molar abundance, they aren't so similar. In this sense, beryllium's abundance is 4.3 ppm; for uranium, it's only 0.15 ppm.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-11-07T09:09:04.997" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2748" PostTypeId="2" ParentId="2732" CreationDate="2014-11-08T06:30:13.243" Score="9" Body="&lt;p&gt;I am posting my code that calculates &lt;code&gt;i_parent_start&lt;/code&gt; and &lt;code&gt;j_parent_start&lt;/code&gt;. It is in Java and as people are aware Java does not have functions such as &lt;code&gt;minloc&lt;/code&gt; or Python's &lt;code&gt;unravel_index&lt;/code&gt;. So I divided my program into three steps.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Read in the &lt;code&gt;xlat_m and xlong_m&lt;/code&gt; arrays using java netcdf.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Subtracting desired lat and desired lon from each value of the&#xA;2-dimensional &lt;code&gt;xlat_m and xlong_m&lt;/code&gt; arrays and squaring the difference.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Then finding the indices &lt;code&gt;i&lt;/code&gt; and &lt;code&gt;j&lt;/code&gt; of the smallest element of&#xA;the 2-dimensional array (not as a flattened 1-d array).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;There is a tool that comes with WRF called the WRF Domain Wizard that creates the parent and child grids but the issue with this is that you can't see the topography and land use that is so essential for high resolution simulations. In order to view the topography I  have another tool that converts the NetCDF file into a KML file and project that on Google Earth. The enclosed image of the child grid is also presented. As explained above for coarse grids this is not so much an issue as it is for nested grids where in the size of the grid itself may not be more than a few hundred meters. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/IQ94Q.jpg&quot; alt=&quot;Location  of child grid as superimposed on Google Earth&quot;&gt; &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;double desiredLatitude = 27;&#xA;double desiredLongitude = 77;&#xA;double[][] xlatMArray = getXLatMArray(dataFile);&#xA;double[][] xlongMArray = getXLongMArray(dataFile);&#xA;int a = xlatMArray.length;&#xA;double[][] array = new double[a][a];&#xA;for (int i =0 ; i &amp;lt; a;i++)&#xA;    {&#xA;    for (int j =0;j &amp;lt; a ;j++)&#xA;        {&#xA;        double latitudeDiff = desiredLatitude - xlatMArray[i][j];&#xA;        double longitudeDiff = desiredLongitude - xlongMArray[i][j];&#xA;        array[i][j]= Math.pow(latitudeDiff,2) + Math.pow(longitudeDiff,2);&#xA;        }&#xA;    }&#xA;double min = array[0][0];&#xA;double max = array[0][0];&#xA;int[] minIndex = {0,0};&#xA;int[] maxIndex = {0,0};&#xA;for (int i =0; i &amp;lt; array.length ; i++)&#xA;    {&#xA;    for (int j =0 ; j &amp;lt;  array.length ; j++)&#xA;        {&#xA;        if (array[i][j] &amp;lt; min)&#xA;            {&#xA;            min = array[i][j];&#xA;            minIndex[0] = i;&#xA;            minIndex[1] = j;&#xA;            }&#xA;        if (array[i][j] &amp;gt; max)&#xA;            {&#xA;            max = array[i][j];&#xA;            maxIndex[0] = i;&#xA;            maxIndex[1] = j;&#xA;            }&#xA;&#xA;        }&#xA;    }&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerDisplayName="user1066" LastEditorUserId="725" LastEditDate="2014-12-16T06:01:56.030" LastActivityDate="2014-12-16T06:01:56.030" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2749" PostTypeId="2" ParentId="322" CreationDate="2014-11-08T11:39:36.233" Score="9" Body="&lt;p&gt;I'd like to elaborate of the &lt;strong&gt;Chemicals&lt;/strong&gt; issue of Azzie Rogers' answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can divide the chemical coloring into three main parts &lt;em&gt;(there may be more, but these are the important ones)&lt;/em&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Inclusions&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A large, solid crystal can have tiny inclusions of other solid minerals. Commonly these inclusions are too small to individually observe by the naked eye. Microscopic methods, either optic or electronic, are usually required to properly identify the inclusions. Nonetheless, when a crystal is viewed on a macroscopic scale, the inclusions give their characteristic color to the mineral.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is one great example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/H0178.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;(&lt;a href=&quot;http://dx.doi.org/10.1017/S0016756813000800&quot; rel=&quot;noreferrer&quot;&gt;Fig. 4 of Anenburg &lt;em&gt;et al.&lt;/em&gt; 2014&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see the blue celestine (strontium sulfate) in the bottom, and the white calcite (calcium carbonate) on top. Their interface is colored red and salmon pink. The reason is the existence of tiny micrometer sized inclusions of iron oxides (&lt;em&gt;i.e.&lt;/em&gt; rust). Note that the iron oxides are different minerals, &lt;em&gt;e.g.&lt;/em&gt; hematite, goethite, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mineral inclusions can sometimes cause even more spectacular effects, such as asterism:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/fb9Jv.jpg&quot; alt=&quot;enter image description here&quot;&gt;&#xA;&lt;sup&gt; (&lt;a href=&quot;https://www.flickr.com/photos/charlestilford/2328058336/&quot; rel=&quot;noreferrer&quot;&gt;source: Charles Tilford&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this case, the cause are tiny inclusions of rutile (titanium oxide).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Crystal field theory&lt;/strong&gt; (allochromatism)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The crystal field theory explains, among other things, what happens to light as it encounters metals in different structural configurations inside a crystal. Keeping the complicated terminology at minimum (&lt;em&gt;energy level splitting yay!&lt;/em&gt;), what basically happens is that different metal cations (positively charged atoms) in a crystalline structure absorb different wavelengths of light. The identity of the metal is not the only important thing: a paramount factor is the number of oxygen atoms that surround the metal atoms and their shape (be it a tetrahedron, octahedron, etc.) These metals are not part of of the formal chemical composition of the mineral. Instead, they replace other atoms in the mineral by very little amounts. For example, ruby is a mineral composed of aluminum oxide. If you take just a bit of this aluminum and replace it with chromium (less than 1% is enough), it becomes vivid red. Note that in contrast to inclusions, we are talking about different metals &lt;em&gt;in the same mineral&lt;/em&gt;, and not inclusions of &lt;em&gt;different minerals&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A digestible explanation with some nice photographs and applets can be found here: &lt;a href=&quot;http://www.chm.davidson.edu/vce/coordchem/cft.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.chm.davidson.edu/vce/coordchem/cft.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Idiochromatism&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the case where the color of the mineral is not dictated by trace amounts of metals in an otherwise colorless mineral (see the ruby example above), but rather by the major chemical constituents of the mineral. A great example is copper, which gives strong green colors to some minerals that contain it (&lt;em&gt;e.g.&lt;/em&gt; malachite):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/4V4z9.jpg&quot; alt=&quot;Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;(&lt;a href=&quot;http://commons.wikimedia.org/wiki/File%3AMalachite-41365.jpg&quot; rel=&quot;noreferrer&quot;&gt;Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or the red color of cinnabar, given by mercury:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/EYEkC.jpg&quot; alt=&quot;Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;(&lt;a href=&quot;http://upload.wikimedia.org/wikipedia/commons/4/4f/Cinnabar-157604.jpg&quot; rel=&quot;noreferrer&quot;&gt;Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC-BY-SA-3.0 (http://creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2014-11-08T11:39:36.233" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2750" PostTypeId="1" AcceptedAnswerId="2775" CreationDate="2014-11-08T14:32:47.610" Score="12" ViewCount="168" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Methane_clathrate&quot;&gt;Methane clathrates&lt;/a&gt; are&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;solid clathrate compound (more specifically, a clathrate hydrate) in which a large amount of methane is trapped within a crystal structure of water, forming a solid similar to ice.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They mostly are on the bottom of the world's oceans; however, the overly brief &lt;a href=&quot;http://en.wikipedia.org/wiki/Methane_clathrate#Continental&quot;&gt;wikipedia section for continental&lt;/a&gt; deposits suggests that it also occurs in Siberia, northern Canada and Alaska.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How much methane clathrates are believed to be buried in these continental deposits?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="6129" LastEditDate="2020-05-06T08:27:29.593" LastActivityDate="2020-05-06T08:27:29.593" Title="How much methane clathrates are buried in continental deposits?" Tags="|economic-geology|gas|methane|clathrates|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2751" PostTypeId="1" CreationDate="2014-11-09T02:39:50.547" Score="5" ViewCount="1386" Body="&lt;p&gt;What type of data is available for ocean depth and density?  For instance, are there measurements of density near Greenland or Antarctica that could be compared to the central Pacific?  It would be nice to have temperature and salinity measurements to go along with the density values.  Also, how deep and how often are measurements made of density as a function of depth in the ocean? &lt;/p&gt;&#xA;" OwnerUserId="1078" LastEditorUserId="543" LastEditDate="2014-11-10T04:04:20.983" LastActivityDate="2014-11-10T04:04:20.983" Title="Where can I find a table of ocean temperature pressure and depth" Tags="|ocean|temperature|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2752" PostTypeId="2" ParentId="2751" CreationDate="2014-11-09T05:40:10.533" Score="5" Body="&lt;p&gt;You can find modeling data on the thermocline depth at the Global Change Master Directory at NASA.  Here is a link that allows you to download the data:&#xA;&lt;a href=&quot;http://gcmd.nasa.gov/records/GCMD_IGOSS_NMC_PACMON_THERMOCLINE.html&quot;&gt;http://gcmd.nasa.gov/records/GCMD_IGOSS_NMC_PACMON_THERMOCLINE.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This data is from hindcast results derived from a model based ocean &#xA;  analysis system. Observed surface and subsurface ocean temperatures as &#xA;  well as satellite altimetry sea-level data from TOPEX/POSEIDON are &#xA;  assimilated into a Pacific basin ocean general circulation model. The &#xA;  model is forced with weekly mean NCEP operational atmospheric analyses &#xA;  of surface winds and heat fluxes. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastActivityDate="2014-11-09T05:40:10.533" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2753" PostTypeId="1" CreationDate="2014-11-09T10:23:57.393" Score="12" ViewCount="1012" Body="&lt;p&gt;The amount of carbon (C) on Earth is constants.  As far as i understand, all carbon that is not found in the atmosphere or the oceans in the form of CO&lt;sub&gt;2&lt;/sub&gt; or CO is stored either in the biomass (plants, animals, including humans, bacteria, mushrooms, etc.), or in fossils and fossil fuels (coal, petroleum, natural gases), or in non-organic form as graphite and diamonds.  Is this correct?  Does it follow that the only way to stop anthropogenic climate change and decrease the amount on CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere is to stop extracting fossil fuels and to start converting CO&lt;sub&gt;2&lt;/sub&gt; from the atmosphere into graphite or diamonds or into some form of petroleum and pump it back under ground?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have asked a &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2755/&quot;&gt;related question about carbon distribution on Earth&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="1079" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2020-04-05T03:41:34.560" Title="To stop anthropogenic climate change, is it necessary to stop extracting petroleum and start pumping carbon under ground?" Tags="|climate-change|carbon-cycle|biomass|fossil-fuel|" AnswerCount="3" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="2755" PostTypeId="1" AcceptedAnswerId="2761" CreationDate="2014-11-09T11:41:05.577" Score="16" ViewCount="1379" Body="&lt;p&gt;In relation to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2753/&quot;&gt;my other question about carbon cycle and climate change&lt;/a&gt;, i would like to know some estimates of the carbon distribution among the atmosphere, the oceans, the biomass and the unburnt fossil fuels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are more specific parts of this question.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;How much carbon is there on Earth?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;How much carbon is there in the atmosphere (in the form of CO&lt;sub&gt;2&lt;/sub&gt; and other gases)?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;How much carbon is there in the oceans in the form of CO&lt;sub&gt;2&lt;/sub&gt; and gases?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;How much carbon is there currently in the biomass?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;How much carbon is there left in the form of fossil fuels?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;If possible, i would also like to know how this distribution has changed, for example, over the last 100 years (in particular, how much carbon from the fossil fuels has been burnt over the last 100 years).&lt;/p&gt;&#xA;" OwnerUserId="1079" LastEditorDisplayName="user12525" LastEditDate="2019-04-30T09:33:06.720" LastActivityDate="2021-02-09T10:58:20.943" Title="How is carbon distributed among the atmosphere, the oceans, the biomass and the unburnt fossil fuels?" Tags="|atmosphere|oceanography|carbon-cycle|biogeochemistry|biomass|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2756" PostTypeId="2" ParentId="2751" CreationDate="2014-11-09T11:49:03.287" Score="8" Body="&lt;p&gt;There are several global products for temperature, salinity and pressure. The product that has been evolving for the longest is likely the World Ocean Database and World Ocean Atlas Series (&lt;a href=&quot;https://www.nodc.noaa.gov/OC5/indprod.html&quot;&gt;https://www.nodc.noaa.gov/OC5/indprod.html&lt;/a&gt;) and their latest product WOA13 is very high quality (&lt;a href=&quot;https://www.nodc.noaa.gov/OC5/woa13/&quot;&gt;https://www.nodc.noaa.gov/OC5/woa13/&lt;/a&gt;). They also have the entire database of used observations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A way to get a global database and also a way to visualize it and extract information is &lt;a href=&quot;http://www.whoi.edu/science/PO/hydrobase/php/index.php&quot;&gt;HydroBase&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another fabulous product that includes global information available monthly for the period 1900 to the present is provided by the &lt;a href=&quot;http://www.metoffice.gov.uk/hadobs/en4/&quot;&gt;Met Office Haddley Centre&lt;/a&gt;. Their latest product is excellent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are looking for model results, one option is to look at the global operational solutions as part of the GODAE initiative. A list of products is &lt;a href=&quot;http://www.godae.org/Ocean-products.html&quot;&gt;here&lt;/a&gt;. Their model products include data assimilation, which helps the model from going to far from reality. The one I am most familiar with is &lt;a href=&quot;https://hycom.org/&quot;&gt;HYCOM&lt;/a&gt;, which provides global data assimilative products at 1/12 degree resolution.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-11-09T11:49:03.287" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2757" PostTypeId="2" ParentId="2753" CreationDate="2014-11-09T11:57:03.383" Score="14" Body="&lt;h3&gt;Summary&lt;/h3&gt;&#xA;&lt;p&gt;Most of the remaining stocks of hydrocarbons (coal, natural gas, oil) will have to remain unburnt. In almost all cases, that will mean leaving them in the ground. We already have proven technology to prevent new emissions of anthropogenic greenhouse gas emissions, and in most cases, the technical and economic barriers are solved: the remaining problem is purely political.&lt;/p&gt;&#xA;&lt;h3&gt;Let's make sure we're talking about the same thing&lt;/h3&gt;&#xA;&lt;p&gt;Let's get our terminology straight first. The big issue is &lt;em&gt;rapid&lt;/em&gt; climate change; and we can do something about that, because the current rapid climate change we are starting to experience, is anthropogenic - it is human-caused.  So, &amp;quot;climate change&amp;quot; here refers &lt;em&gt;not&lt;/em&gt; to historic natural processes over thousands to millions of years, but the present anthropocentric-induced processes that are happening over decades. That is the most common usage of the phrase these days, but it still can be useful to state it explicitly once in a while so that we know we are discussing the same thing.&lt;/p&gt;&#xA;&lt;h3&gt;Stocks and flows&lt;/h3&gt;&#xA;&lt;p&gt;Climate change is a result of &lt;em&gt;changes&lt;/em&gt; in the stock of greenhouse gases in the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;Those stocks have increased a lot over the last 180 years or so, and are continuing to change, because we've messed about with the flows. In particular, we've increased the rate of emissions from sources, without increasing the rate of take-up of sinks.&lt;/p&gt;&#xA;&lt;p&gt;The bathtub analogy: we've opened the bath taps further, so water's flowing in faster. But we haven't widened the drain, so the level of water in the bath is rising, and soon will overflow and flood the house. It's not the rate at which water enters the bath that's the problem in and of itself: it's the level of water in the bath, and that's rising quickly because the inflow is much faster than the outflow. Similarly, what matters for climate and climate change is the level of greenhouse gases in the atmosphere, and the level of CO&lt;sub&gt;2&lt;/sub&gt; absorbed into the oceans.&lt;/p&gt;&#xA;&lt;p&gt;Even if new net emissions went to zero this year (technically impossible without the collapse of human civilisation, which would rather defeat the whole exercise), we'd still see increasing heat content of the Earth over the next few years, as things move towards equilibrium, based on the current levels of greenhouse gases which represent a historic increase over the levels that prevailed over the last few thousand years during which human civilisation has developed.&lt;/p&gt;&#xA;&lt;p&gt;So, to prevent further climate change, we have to balance out sources and sinks. So we can do either, or a combination, of two things: we can decrease the rate of emissions from sources down to the level where existing sinks can absorb them; and we can increase the rate at which sinks absorb.&lt;/p&gt;&#xA;&lt;h3&gt;Reducing sources&lt;/h3&gt;&#xA;&lt;p&gt;Stopping burning fossil fuels is the easiest and simplest way to decrease the rate of emissions. To the best of my knowledge, we now have alternatives for almost all of the major emissions sources, with the possible exception of methane emissions from livestock farming. Some are very well-established, like hydro and onshore wind electricity generation. Some are maturing quickly, like PV, offshore wind. Some are successful in the lab, and ready to move to commercial-scale prototypes, such as decarbonised production of steel, clinker, and liquid hydrocarbons.&lt;/p&gt;&#xA;&lt;h3&gt;Increasing sinks&lt;/h3&gt;&#xA;&lt;p&gt;Carbon sequestration is one way to increase the sinks. It's been trialled at small scale, and remains problematic. The way that's been done so far is to pump the carbon dioxide underground. At the moment, no business has been willing to accept the open-ended liability that is posed by the risk of leakage. So at the moment, the market is saying that this is not a viable technology. That might change. It's also worth noting that at the moment, the market also wants to use CO&lt;sub&gt;2&lt;/sub&gt; sequestration as a means of extracting even more oil (Enhanced Oil Recovery, EOR), which just makes the whole problem worse.&lt;/p&gt;&#xA;&lt;p&gt;One way that is fast, effective and affordable is increasing the amount of carbon in biomass. Reforestation and afforestation are two ways to do this, and would help reverse a lot of the human-caused loss of forest ecosystems, if done well.&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-12-18T07:04:15.423" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2760" PostTypeId="1" AcceptedAnswerId="2763" CreationDate="2014-11-10T12:15:29.733" Score="13" ViewCount="233" Body="&lt;p&gt;The iridium anomaly marks the elevated concentration of iridium in sedimentary deposits of the Cretaceous-Paleogene boundary. The iridium is said to come from the impactor, which is supposed to have much higher iridium contents than Earth's crust.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What about other metals? Is there an observed increase of other elements as well? For example, osmium is another extremely rare element in the crust. Is there an osmium anomaly as well? If not, why is the anomaly restricted to iridium and not the other metals?&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-08-12T05:04:33.970" Title="Are there any metal anomalies other than iridium in the K-Pg boundary?" Tags="|geochemistry|mass-extinction|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2761" PostTypeId="2" ParentId="2755" CreationDate="2014-11-10T16:04:10.100" Score="12" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;1.How much carbon is there on Earth?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Taken as whole, the Earth is estimated to be 730 parts per million carbon by mass. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So $4.4 \times 10^{21} kg$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://quake.mit.edu/hilstgroup/CoreMantle/EarthCompo.pdf&quot; rel=&quot;noreferrer&quot;&gt;http://quake.mit.edu/hilstgroup/CoreMantle/EarthCompo.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ol start=&quot;2&quot;&gt;&#xA;  &lt;li&gt;How much carbon is there in the atmosphere (in the form of CO&lt;sub&gt;2&lt;/sub&gt; and CO)?&lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;$3.1 \times 10^{15} kg$ CO&lt;sub&gt;2&lt;/sub&gt; and insignificant CO, so $8 \times 10^{14}$ kg of C. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ol start=&quot;3&quot;&gt;&#xA;  &lt;li&gt;How much carbon is there in the oceans in the form of CO&lt;sub&gt;2&lt;/sub&gt; and CO?&lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Carbon of all forms in the the ocean is $4 \times 10^{16} kg$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://ioc-goos-oopc.org/documents/oosdp/oosdp_br5.pdf&quot; rel=&quot;noreferrer&quot;&gt;http://ioc-goos-oopc.org/documents/oosdp/oosdp_br5.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ol start=&quot;4&quot;&gt;&#xA;  &lt;li&gt;How much carbon is there currently in the biomass?&lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;$8 \times 10^{14}$ kg (not including soil)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$2 \times 10^{15}$ kg (if soil is included)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ol start=&quot;5&quot;&gt;&#xA;  &lt;li&gt;How much carbon is there left in the form of fossil fuels?&lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;$5 \times 10^{15} kg$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.gcrio.org/CONSEQUENCES/vol4no1/carbcycle.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.gcrio.org/CONSEQUENCES/vol4no1/carbcycle.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(This could be an underestimate, depending upon what you consider to be &quot;fossil fuel&quot;; methane clathrates are estimated to hold $10^{16}$ kg of carbon)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If possible, i would also like to know how this distribution has changed, for example, over the last 100 years (in particular, how much carbon from the fossil fuels has been burnt over the last 100 years).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The amount of carbon in the atmosphere has increased about 30% since pre-industrial times, and the amount in biomass, not including soil, has decreased about 10%.  Amount in the oceans has not changed significantly.&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2014-11-12T14:31:35.020" LastActivityDate="2014-11-12T14:31:35.020" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2762" PostTypeId="2" ParentId="310" CreationDate="2014-11-10T17:52:28.187" Score="8" Body="&lt;p&gt;&lt;strong&gt;What are the rare earths?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rare earths are a group of several elements. The widest definition includes the 15 lanthanides: La, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu, and two more elements: Sc and Y. A quick look at the periodic table gives a hint as to why Sc and Y are also considered as REE:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ep2xr.png&quot; alt=&quot;the rare earth elements (REE)&quot;&gt;&#xA;&lt;sup&gt;(modified from &lt;a href=&quot;http://www.texample.net/tikz/examples/periodic-table-of-chemical-elements/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've marked all the REE in red borders and larger font size. You can see that the lanthanide row is actually an expansion of a hypothetical &quot;element&quot; that would otherwise be in period 6 and group 3, just below Sc and Y.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why are they grouped together? All the REE share very similar chemical properties, and change continuously from La to Lu, where Y sits somewhere between Dy and Ho (properties-wise). This results from their electron configuration, but that's for another question. Notice that Pm does not have any stable isotopes and is not a naturally occurring element, so actually there are only 14+2 rare earth elements.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why are they called rare earths? &lt;a href=&quot;https://en.wikipedia.org/wiki/Lanthanide#Etymology&quot; rel=&quot;nofollow noreferrer&quot;&gt;One source&lt;/a&gt; (&lt;a href=&quot;http://www.vanderkrogt.net/elements/rareearths.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;also this&lt;/a&gt;) claims that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This name arises from the minerals from which they were isolated,&#xA;  which were uncommon oxide-type minerals. However, the use of the name&#xA;  is deprecated by IUPAC, as the elements are neither rare in abundance&#xA;  nor &quot;earths&quot; (an obsolete term for water-insoluble strongly basic&#xA;  oxides of electropositive metals incapable of being smelted into metal&#xA;  using late 18th century technology).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Rare_earth_element&quot; rel=&quot;nofollow noreferrer&quot;&gt;And another&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...rare earth elements are typically dispersed and not often found&#xA;  concentrated as rare earth minerals in economically exploitable ore&#xA;  deposits.&lt;a href=&quot;https://en.wikipedia.org/wiki/Lanthanide#Etymology&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt; It was the very scarcity of these minerals (previously&#xA;  called &quot;earths&quot;) that led to the term &quot;rare earth&quot;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Although the IUPAC definition includes Sc and Y in the REE, in the professional literature they are commonly distinguished. This can be easily seen in a quick Google Scholar search:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/kGhGg.png&quot; alt=&quot;REE in Google Scholar&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From my own personal experience, Sc is rarely considered in the geological literature considering REE. Also see &lt;a href=&quot;https://earthscience.stackexchange.com/a/2951/725&quot;&gt;https://earthscience.stackexchange.com/a/2951/725&lt;/a&gt; where in the figure you can see that Sc, at least in terms of ionic radius, is unlike the rest of the REE. Y is added to the REE, but not considered a part of them, causing the rise of the term &quot;REY&quot; (REE+Y).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Are the rare earth elements really rare?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not really. Here's a diagram of element abundance in Earth's crust:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/2smh1.gif&quot; alt=&quot;Elemental abundance in the crust&quot;&gt;&#xA;&lt;sup&gt;(&lt;a href=&quot;http://pubs.usgs.gov/fs/2002/fs087-02/&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Note that according to this, Sc is not considered a REE. Conversely, the &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Elemental_abundances.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; version of this diagram includes it.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see that the REE are not that rare. The light rare earth elements are close to some transition elements in the crustal abundance, and even the the least abundance REE (Tm and Lu) are still more abundant than silver or mercury. Y and Sc are less abundant than their neighbours, but this can be attributed to the &lt;a href=&quot;https://duckduckgo.com/l/?kh=-1&amp;amp;uddg=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FOddo-Harkins_rule&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oddo-Harkins&lt;/a&gt; rule and not to the fact they are are REE. So why are they still &quot;rare&quot;? They rarely form ore deposits of their own. While other, less abundant, metals readily concentrate and form easily exploitable economic deposits (gold nuggets, anyone?), the REE are usually dispersed within other minerals. When they do form minerals of their own (&lt;em&gt;e.g.&lt;/em&gt; allanite, monazite, xenotime), they are usually not abundant enough to form a deposit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Why are they associated with alkali rocks?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alkali rocks (&lt;em&gt;e.g.&lt;/em&gt; carbonatites, syneites, etc.) are indeed enriched in REE-bearing minerals (pyrochlore is one that comes into mind). The fine details of trace element (REE and others) enrichment of alkali rocks and the formation of alkali magmas are still debated. Still, the basic idea is now mostly well understood. Most alkali magmas form by very low degree of melting of relatively deep mantle rocks (deeper than those that produce basalts, for example). The low degree of melting causes element that are incompatible in mantle rocks to significantly concentrate in the liquid. That's why these liquids are alkali - Na and K are incompatible in the mantle, as well as REE.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can read more about alkali magmas in chapter 9 of the excellent book &quot;&lt;a href=&quot;http://eu.wiley.com/WileyCDA/WileyTitle/productCd-EHEP002306.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Igneous Rocks and Processes&lt;/a&gt;&quot; by Robin Gill.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-12-04T07:34:21.307" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2763" PostTypeId="2" ParentId="2760" CreationDate="2014-11-10T19:50:03.847" Score="8" Body="&lt;p&gt;According to the conference article &lt;a href=&quot;http://www.lpi.usra.edu/meetings/lpsc2013/pdf/2167.pdf&quot;&gt;Can Siderophile Element Abundances and Ratios across the K-Pg Boundary be used Discriminate between Possible Types of Projectiles?&lt;/a&gt;, (Belza et al. 2013) state that the enrichment is not only in Iridium, but also in the other Platinum Group Elements and siderophile elements.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the article &lt;a href=&quot;http://www.ruf.rice.edu/~ctlee/GCAKTB2003.pdf&quot;&gt;Platinum-group elements (PGE) and rhenium in marine sediments across the Cretaceous–&#xA;Tertiary boundary: Constraints on Re-PGE transport in the marine environment&lt;/a&gt; (Lee et al. 2003) elaborates that from&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A traverse&#xA;  across the KTB in the South Pacific pelagic clay core found elevated levels of Re, Pt, Ir, Os, and Ru, each of&#xA;  which is approximately symmetrically distributed over a distance of 1.8 m across the KTB. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(KTB is a reference to Cretaceous-Tertiary Boundary from the article).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a re-evaluation of geochemical data in &lt;a href=&quot;http://we.vub.ac.be/~dglg/Web/Claeys/pdf/Goderis-2013-GCA.pdf&quot;&gt;Reevaluation of siderophile element abundances and ratios&#xA;across the Cretaceous–Paleogene (K–Pg) boundary:&#xA;Implications for the nature of the projectile&lt;/a&gt; (Goderis et al. 2013), took into account several more studies (published and unpublished), find that cobalt, chromium and nickel display in &lt;em&gt;some places&lt;/em&gt;, an elevated concentration; however, the Co/Cr, Ni/Co, Ni/Cr, Co/Ir, Ni/Ir and Cr/Ir ratio are considerably higher than that of the average continental crust, which the authors suggest is consistent with chondrites.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-11-10T19:50:03.847" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2765" PostTypeId="1" CreationDate="2014-11-11T15:24:51.107" Score="32" ViewCount="4061" Body="&lt;p&gt;It is a common misconception that Coriolis is responsible for the direction the water swirls down a toilet, tub or sink drain.  E.g. does a toilet flush the other way in the southern hemisphere? (If it does, it is due to the construction of the basin, not Coriolis).  This misconception has been debunked many times and leads to a new issue I ran into recently.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was talking to someone about low pressure systems (cyclones, e.g. mid-latitude storms and tropical cyclones) spinning in the opposite sense in the the north and south hemispheres and they questioned this fact because &quot;Coriolis does not determine how something spins, Mythbusters showed that with a toilet&quot;. This demonstrates a lack of understanding in how Coriolis works and leads to this question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why does Coriolis determine the sense of rotation of a cyclone but not my drain?  How can it work on one phenomenon but not the other?&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2014-11-13T22:08:59.673" LastActivityDate="2014-11-17T16:29:43.657" Title="Why does Coriolis determine the rotation direction of a cyclone but not my drain?" Tags="|meteorology|coriolis|dynamics|fluid-dynamics|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2766" PostTypeId="2" ParentId="2765" CreationDate="2014-11-11T16:27:51.440" Score="25" Body="&lt;p&gt;The answer is the scale.&#xA;The fluid movement of a sink has a much smaller curvature radius than the grand-scale movements of a hurricane.&#xA;This curvature radius plays a big role on whether your movement due to a pressure gradient will be balanced by coriolis, or centrifugal forces, as thorougly discussed &lt;a href=&quot;http://en.wikipedia.org/wiki/Balanced_flow&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can read this wikipage, but the essence is the following:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you transform the equations that govern the movement of a fluid parcel into a coordinate system that moves along with the flow, you find the following &lt;em&gt;force balance&lt;/em&gt; that counteracts the pressure gradient:&#xA;$$ \frac{v^2}{R} + f v = - \frac{1}{\rho} \nabla P $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here we have simply two effects that arise from the translation to a rotating reference frame balancing the pressure gradient. The first one is known as the centrifugal pseudoforce, the second one is the coriolis force.&#xA;If you're interested in a derivation, see &lt;a href=&quot;http://en.wikipedia.org/wiki/Centrifugal_force_%28rotating_reference_frame%29&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;, the linearization is then straightforward.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From those terms one can clearly see that fast dynamics (tornado!), or small curvature (toilet) will lead to the l.h.s dominated by the centrifugal term. However for large-scale and slow flows (hurricanes, cyclones etc.) the left side will be dominated by the coriolis term.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;As to the question in which direction a certain flow can occur, let's remember that in co-moving coordinates each scalar quantity has however a sign. $v$ changes sign if we turn the wind direction, $R$ the curvature radius sign depends on where the movement is going, $f$ on which hemisphere we are.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we now take a look at coriolis vs. pressure gradient force (geostrophic balance), we see that this balance has only one direct solution for a sign of $v$ for a given f. Therefore the predetermined direction of geostrophic cyclones for each hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However the solution for $v$ in the cyclostrophic case is obviously&#xA;$$v = \sqrt{-\frac{R}{\rho} \nabla P} $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which can never be satisfied for high-pressure systems as then curvature sign and gradient sign cancel out and leave the term imaginary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However one can easily visualize where the forces are pointing:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/Pvxxi.png&quot; alt=&quot;$F_p$ is the pressure gradient force, $F_c$ Coriolis and $F_{ce}$ the centrifugal force. + and - denote the root&amp;#39;s solution. Property of K. Roth, Heidelberg University.&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;($F_p$ is the pressure gradient force, $F_c$ Coriolis and $F_{ce}$ the centrifugal force. + and - denote the root's solution. Property of K. Roth, Heidelberg University.)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here in the case of cyclostrophic balance just look where the red arrow can cancel the green one and you see how Tornadoes do not care for the hemisphere, but just for low-pressure systems and can go in any direction around this.&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="489" LastEditDate="2014-11-17T16:29:43.657" LastActivityDate="2014-11-17T16:29:43.657" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2767" PostTypeId="2" ParentId="2765" CreationDate="2014-11-11T16:40:58.420" Score="17" Body="&lt;p&gt;This question can be answered with a scaling argument.  Let us start with the momentum equation (Navier-Stokes) in a non-intertial reference frame (e.g. on the rotating earth) and assuming inviscid flow (roughly true above the surface).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\dfrac{\partial\mathbf u}{\partial t} = - \mathbf u \cdot \nabla \mathbf u  -\dfrac{1}{\rho}\nabla p-2 \mathbf \Omega \times \mathbf u + \mathbf g$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because we are interested in horizontal motions, lets break this vector form into meridonal and zonal momentum and expand the derivatives.  We will define $f = 2\Omega \sin \varphi$, where $\varphi$ is latitude.  The gives us:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\dfrac{\partial u}{\partial t} + u\dfrac{\partial u}{\partial x} + v\dfrac{\partial u}{\partial y} + w\dfrac{\partial u}{\partial z} =  -\dfrac{1}{\rho}\dfrac{\partial p}{\partial x} +fv$$&#xA;$$\dfrac{\partial v}{\partial t} + u\dfrac{\partial v}{\partial x} + v\dfrac{\partial v}{\partial y} + w\dfrac{\partial v}{\partial z} =  -\dfrac{1}{\rho}\dfrac{\partial p}{\partial y} - fu$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this formulation, the terms $+fv$ and $-fy$ represent Coriolis acceleration.  Now we can perform a scaling analysis and determine which terms of the equation are important at various scales.  Because the scales between the two equations are the same, I will only show the scaling argument for the $u$ momentum equation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let us write:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\dfrac{\partial U}{\partial T} + U\dfrac{\partial U}{\partial L} + U\dfrac{\partial U}{\partial L} + W\dfrac{\partial U}{\partial Z} =  -\dfrac{1}{\rho}\dfrac{\partial P}{\partial L} +fU$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And then noting that terms 2 and 3 are equivalent and discarding the derivative notation we end up with with these terms (I've also dropped the arithmetic operations as we are now just interested in comparing orders of magnitude):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\dfrac{U}{T} ,\ \dfrac{U^2}{L} ,\ W\dfrac{U}{H} ,\  -\dfrac{1}{\rho}\dfrac{P}{L} ,\ fU$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This may look funny and unrelated to our equation of motion, but we are only looking to determine the order of magnitude of various terms and this scaling analysis lets us do this.  The scaling values are $U$ - velocity scale, $T$ - time scale, $L$ - length scale, $W$ - vertical motion scale, $H$ - depth scale, $\rho$ - density scale, $P$ - pressure scale, and $f$ - Coriolis scale.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For synoptic scale motions we will use $U = 10\ \mathrm{m\ s^{-1}}$, $L = 10^6\ \mathrm{m}$, $W = 0.01\ \mathrm{m\ s^{-1}}$, $H = 10^4\ \mathrm{m}$, $\rho = 1\ \mathrm{kg\ m^{-3}}$, $P = 10^3\ \mathrm{Pa}$, $T = 10^5\ \mathrm{s^{-1}}$ and $f = 10^{-4}\ \mathrm{s^{-1}}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plugging these scalings into the above equation yields:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\dfrac{10}{10^5} ,\dfrac{10^2}{10^6} ,\ 10^{-2}\dfrac{10}{10^4} ,\ \dfrac{10^3}{10^6} ,\ 10^{-4}10$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which reduces to:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$10^{-4},\ 10^{-4},\ 10^{-5},\ 10^{-3},\ 10^{-3}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This scaling argument tells us that the time derivative and the horizontal derivatives are unimportant (especially the vertical motion) and that Coriolis and the pressure gradient force are the most important.  If we use this scaling argument to drop the unimportant terms the equation for $u$ momentum we are left with is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$0 =  -\dfrac{1}{\rho}\dfrac{\partial p}{\partial x} +fv$$&#xA;$$0 =  -\dfrac{1}{\rho}\dfrac{\partial p}{\partial y} -fu$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which when re-written may be more familiar to some of us:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$u_g = -\dfrac{1}{\rho f}\dfrac{\partial p}{\partial y}$$&#xA;$$v_g = \dfrac{1}{\rho f}\dfrac{\partial p}{\partial x}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which are the horizontal momentum equations in geostrophic flow.  Another thing that drops out of the scaling argument is the Rossby number.  Recall:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\dfrac{U}{T} ,\ \dfrac{U^2}{L} ,\ W\dfrac{U}{H} ,\  -\dfrac{1}{\rho}\dfrac{P}{L} ,\ fU$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we use $U = L/T$ and divide by the Coriolis scaling $fU$, we end up with:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\dfrac{U}{fL} ,\ \dfrac{U}{fL} ,\ \dfrac{W}{fH} ,\  -\dfrac{1}{\rho}\dfrac{P}{UfL} ,\ 1$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Focusing on the first two terms which are the time and space derivatives we can determine when Coriolis is important with the non-dimensional number $Ro = \dfrac{U}{fL}$, or the Rossby number.  When $Ro &amp;lt;&amp;lt; 1$ Coriolis is important and when $Ro &amp;gt;&amp;gt; 1$ Coriolis can be neglected.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Lets apply what we've learned above and use the Rossby number in the synoptic scale (e.g. big cyclones) and in our toilet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once again, at synoptic scale we'll use $U = 10\ \mathrm{m\ s^{-1}}$, $L = 10^6\ \mathrm{m}$, and $f = 10^{-4}\ \mathrm{s^{-1}}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In our toilet we'll use $U = 0.5\ \mathrm{m\ s^{-1}}$, $L = 0.3\ \mathrm{m}$, and $f = 10^{-4}\ \mathrm{s^{-1}}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Rossby number in the synoptic scale is: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$Ro = \dfrac{U}{fL} = 0.1 &amp;lt;&amp;lt; 1$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Rossby number in the toilet is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$Ro = \dfrac{U}{fL} \approx 10^3 &amp;gt;&amp;gt; 1$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This tells us that if we were to revisit the scaling argument we used to develop the Rossby number but instead in our toilet, that we'd find the accelerations to be much more important than Coriolis and that we can neglect that force.  Also note that you do not have to get as small as a toilet to be unaffected by Coriolis.  Tornadoes, for example, are unaffected by Coriolis and it isn't until you have long lived mesoscale convective complexes (MCC) and mesoscale convective vortices (MCV) that you start to see the effect of Coriolis on storm structure.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2014-11-11T18:32:29.420" LastActivityDate="2014-11-11T18:32:29.420" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2769" PostTypeId="2" ParentId="2765" CreationDate="2014-11-11T19:30:40.617" Score="13" Body="&lt;p&gt;You can think about it like this: It takes one day for the earth to perform a full rotation (about 86k seconds), on the other hand, it takes a few seconds for your sink to drain (lets say 10 seconds). So it takes 8600 times longer for the earth to do a full rotation than it takes the water to drain down the sink. It is not too hard to imagine that the earth's rotation can have no influence on the process of draining a sink (as compared to other forces it feels, due to various things such as imperfections in the sink, etc).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, if the sink was the size of lake Michigan and you were to drain it, Coriolis would play a role.&lt;/p&gt;&#xA;" OwnerUserId="200" LastActivityDate="2014-11-11T19:30:40.617" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2770" PostTypeId="2" ParentId="103" CreationDate="2014-11-12T03:22:05.357" Score="4" Body="&lt;p&gt;Another way of telling the hemisphere is with the phases of the moon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the northern hemisphere, the illuminated part of the moon &quot;moves&quot; from right to left, the opposite from the southern hemisphere, in which it moves from left to right.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For more details, check wikipedia: &lt;a href=&quot;http://en.wikipedia.org/wiki/Lunar_phase&quot; rel=&quot;nofollow&quot;&gt;Lunar Phase&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1093" LastActivityDate="2014-11-12T03:22:05.357" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2771" PostTypeId="1" AcceptedAnswerId="2787" CreationDate="2014-11-12T06:32:10.443" Score="9" ViewCount="261" Body="&lt;p&gt;For the past few years in succession India has witnessed extreme flooding events caused by monsoonal troughs colloding with what appears transitory mid latitude disturbances and these appear to trigger flash floods. Case in point - &lt;a href=&quot;http://en.wikipedia.org/wiki/2013_North_India_floods&quot;&gt;http://en.wikipedia.org/wiki/2013_North_India_floods&lt;/a&gt; and &lt;a href=&quot;http://en.wikipedia.org/wiki/2014_India%E2%80%93Pakistan_floods&quot;&gt;http://en.wikipedia.org/wiki/2014_India%E2%80%93Pakistan_floods&lt;/a&gt;. My question relates to the physics of such interactions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Following are my questions:&lt;br/&gt;&#xA;1) The northward propagating waves emanating at the 850 hPa level from the MJO(BSISO) appear to be damped at the Himalayan foothills(30 N latitude). Following orographic interactions I presume the 850 hpA 's geopotential height appears to be raised. Is that an accurate statement i.e. in the mountains the 850 hPa monsoonal trough's geopotential height is higher(much higher) than at sea levels?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Then the planetary wave at the 500 hPa level then appears to be dipping down in the tropics and interacting with monsoonal troughs. How does a upper level trough &quot;propagate&quot; down ? Is this due to quasi geostropic theory?&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorUserId="6441" LastEditDate="2016-11-21T20:54:07.530" LastActivityDate="2016-11-21T20:54:07.530" Title="Monsoonal interactions with mid latitude disturbances" Tags="|meteorology|atmospheric-circulation|monsoon|troposphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2772" PostTypeId="1" AcceptedAnswerId="2777" CreationDate="2014-11-12T12:24:57.657" Score="41" ViewCount="7536" Body="&lt;p&gt;At first glance, this seems like such a simple question of &quot;What's the highest point on Earth&quot;.  However, I also know that the Earth isn't perfectly round.  So that &quot;highest point&quot; may be in a relative valley.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, because it's non-spherical, the &quot;center&quot; may not be easily obvious either.  So, I'm curious if there are different answers based on different definitions of &quot;center&quot; (such as geographic center versus center of mass).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, what is the point on the Earth's surface farthest from the center of the Earth?  Is this different based on different definitions of &quot;center&quot;?&lt;/p&gt;&#xA;" OwnerUserId="330" LastEditorDisplayName="user12525" LastEditDate="2019-04-15T14:05:12.007" LastActivityDate="2019-04-15T14:05:12.007" Title="Farthest point from the center of the Earth" Tags="|geology|geophysics|mountains|topography|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2774" PostTypeId="2" ParentId="2772" CreationDate="2014-11-12T12:57:02.297" Score="23" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Chimborazo&quot; rel=&quot;noreferrer&quot;&gt;Mount Chimborazo&lt;/a&gt;, which is 6,268 meters above sea level and within 1.5 degrees of the equator.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;More specifically, &lt;a href=&quot;http://geodesy.geology.ohio-state.edu/course/refpapers/Earth99.pdf&quot; rel=&quot;noreferrer&quot;&gt;according to Dr. Milbert, Chief Geodesist, NOAA, National Geodetic Survey and Dr. Shum, Geodetic Science &amp;amp; Surveying, Ohio State Univ.&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;distance from Earth's center of mass, with an uncertainty of only +/- 2 meters:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mt. Chimborazo - 6384.459 kilometers &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mt. Huascaran  - 6384.372 kilometers &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mt. Cotopaxi  - 6384.062 kilometers &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mt. Kilimanjaro - 6383.955 kilometers&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2016-01-11T14:20:39.877" LastActivityDate="2016-01-11T14:20:39.877" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2775" PostTypeId="2" ParentId="2750" CreationDate="2014-11-12T14:22:10.420" Score="3" Body="&lt;p&gt;According to &lt;a href=&quot;http://link.springer.com/article/10.1007%2FBF00144504&quot; rel=&quot;nofollow&quot;&gt;Role of methane clathrates in past and future climates&lt;/a&gt;, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Methane occurrences and the organic carbon content of sediments are&#xA;  the bases used to estimate the amount of carbon currently stored as&#xA;  clathrates. The estimate of about 11,000 Gt of carbon for ocean&#xA;  sediments, and about 400 Gt for sediments under permafrost&#xA;  regions...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So 400 billion tons.  &lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="725" LastEditDate="2014-12-18T06:59:00.053" LastActivityDate="2014-12-18T06:59:00.053" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2777" PostTypeId="2" ParentId="2772" CreationDate="2014-11-12T16:00:12.920" Score="57" Body="&lt;p&gt;It's &lt;a href=&quot;https://en.wikipedia.org/wiki/Chimborazo&quot; rel=&quot;noreferrer&quot;&gt;Chimborazo, Ecuador&lt;/a&gt;, but only just, beating &lt;a href=&quot;https://en.wikipedia.org/wiki/Huascar%C3%A1n&quot; rel=&quot;noreferrer&quot;&gt;Huascarán, Peru&lt;/a&gt;, by less than 50 metres. Both are over 2 km 'higher' than Everest.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I made a plot of some mountains — height above centre of the earth vs absolute latitude. You can download the &lt;a href=&quot;https://gist.github.com/kwinkunks/a449bff4c8c35952e6ce&quot; rel=&quot;noreferrer&quot;&gt;IPython Notebook source code here&lt;/a&gt;. Warning: v. hacky.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/3VwGa.png&quot; alt=&quot;the heights of some mountains, relative to the centre of the earth.&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can't find anything on the position of the centre of the earth. The formula I used for the latitude-dependent radius requires major (equatorial) and minor (polar) radii, but I don't have citations for them either. Argus in his article &lt;a href=&quot;http://dx.doi.org/10.1111/j.1365-246X.2007.03344.x&quot; rel=&quot;noreferrer&quot;&gt;Defining the translational velocity of the reference frame of Earth&lt;/a&gt; gave some numbers for its temporal variance, but I have no idea how this might affect these mountain heights. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Last thing: Apparently, the floor of the Arctic Ocean is the closest point on the surface to the Earth's center (about 6353 km, 30 km 'below' Chimborazo), if you call the bottom of the sea the 'surface'. &lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="6093" LastEditDate="2016-12-07T07:29:48.620" LastActivityDate="2016-12-07T07:29:48.620" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2778" PostTypeId="1" CreationDate="2014-11-12T16:15:24.703" Score="21" ViewCount="1585" Body="&lt;p&gt;Heavier elements are created in stars.  After stars die they scatter these heavier elements throughout the universe.  These elements eventually gather to form planets.  But why do we find &quot;chunks&quot; of gold, silver, etc. and not scattered atoms throughout the earth.  In other words, how do the atoms of these elements come together to form chunks of the same element involving billions and billions of atoms?  &lt;/p&gt;&#xA;" OwnerUserId="1100" LastEditorUserId="20" LastEditDate="2014-11-15T02:24:51.130" LastActivityDate="2014-11-15T08:44:05.973" Title="Why are minerals found in &quot;large&quot; quantities and not scattered throughout the earth as individual atoms?" Tags="|geophysics|geology|earth-history|mineralogy|economic-geology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2779" PostTypeId="2" ParentId="69" CreationDate="2014-11-12T18:23:36.153" Score="4" Body="&lt;p&gt;The reason that the gradients persist is that atmospheric processes are part of an engine, driven by the energy of the sun. If the sun were to burn out, then the gradients would then in fact dissipate. But until then, the sun will heat the air at the surface near the equator, while the cold air sinks at the poles, creating a circulation around the earth (see Hadley cells). The fronts are the boundaries of the eddies formed in the circulation.&lt;/p&gt;&#xA;" OwnerUserId="1105" LastActivityDate="2014-11-12T18:23:36.153" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2780" PostTypeId="2" ParentId="2778" CreationDate="2014-11-12T18:33:46.610" Score="6" Body="&lt;p&gt;The simple answer is that the Earth is dynamic, e.g. plate tectonics.  This wikipedia article on ore genesis is a good place to start, &lt;a href=&quot;http://en.wikipedia.org/wiki/Ore_genesis&quot; rel=&quot;noreferrer&quot;&gt;http://en.wikipedia.org/wiki/Ore_genesis&lt;/a&gt; .&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Ore genesis theories generally involve three components: source, transport or conduit, and trap. This also applies to the petroleum industry, which was first to use this methodology.  Source is required because metal must come from somewhere, and be liberated by some process. Transport is required first to move the metal bearing fluids or solid minerals into the right position, and refers to the act of physically moving the metal, as well as chemical or physical phenomenon which encourage movement. Trapping is required to concentrate the metal via some physical, chemical or geological mechanism into a concentration which forms mineable ore.  The biggest deposits are formed when the source is large, the transport mechanism is efficient, and the trap is active and ready at the right time.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastActivityDate="2014-11-12T18:33:46.610" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2781" PostTypeId="1" CreationDate="2014-11-12T18:55:11.133" Score="8" ViewCount="539" Body="&lt;p&gt;It is a proven fact that the gravitational force exerted upon an object directly affects that objects experience of time; the greater the gravity, the slower time passes, and visa versa. While the rate of radioactive decay may be nearly absolute, the gravitational environment in which that decay took place dictates how time was experienced by the decaying atom.&#xA;    Gravitational environment differs with respect to altitude, and would also differ based on the weight and density of material in which an object was located. Furthermore, gentle gravitational waves ripple across the face of this planet every day, creating the weather of our atmosphere. It is also highly probable that the earth has experienced a myriad of intense gravitational events over its history, during unstable periods of solar radiation, and from the ripples of other catastrophic cosmic events.&#xA;    I am very curious to read any research in this area.&lt;/p&gt;&#xA;" OwnerUserId="1104" LastActivityDate="2014-11-14T07:00:38.040" Title="How do archaeologists address time dilation when analyzing carbon dating results?" Tags="|geophysics|geochemistry|earth-history|planetary-science|paleontology|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2782" PostTypeId="2" ParentId="935" CreationDate="2014-11-12T19:56:04.813" Score="12" Body="&lt;p&gt;There has been some considerable attention, it is not that factor that is hampering more coherent action, it is a lack of full understanding of the fine particulate matter itself - allow me to explain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A lot of the reason why there has only been largely piecemeal approaches to combat Fine Particulate Matter, globally speaking, is due to the incomplete understanding of the aerosols and their dynamics themselves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Having said that, there are different strategies to combat fine particulate matter (FPM). But, first, a definition - the United Nations Environment Program (UNEP) page &lt;a href=&quot;http://www.unep.org/tnt-unep/toolkit/pollutants/facts.html&quot;&gt;Pollutants: Particulate matter (PM)&lt;/a&gt; states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;PM 2.5 refers to particles with a diameter of less than 2.5 microns. &lt;strong&gt;These are usually called fine particles&lt;/strong&gt; and contain secondary aerosols, combustion particles and re-condensed organic metallic vapour, and acid components. Fine particles can reach all the way down to the alveoli in the lungs.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The inclusion of secondary aerosols, combustion particles (e.g. soot) and recondensed organo-metallic vapour can and does complicate attempts to mitigate the effects once released and would also complicate attempts to prevent the release.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It could be argued that the ultrafine fraction at 0.1 microns and less could be included under the FPM umbrella; however, as stated on the UNEP page, these are still the focus of extensive research.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are several documents calling for the control and providing practical strategies by governmental organisations, one such document is the US EPA's &lt;a href=&quot;http://www.epa.gov/glo/SIPToolkit/documents/PM25Menu-Final.pdf&quot;&gt;Controlling &#xA;Fine Particulate Matter &#xA;Under the Clean Air Act: &#xA;A Menu of Options&lt;/a&gt; (2006), in which it is acknowledged that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The chemistry and physics of PM2.5 formation in the &#xA;  atmosphere is incompletely understood. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;also, in a practical sense,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In a perfect &#xA;  world, control-efficiency and cost-effectiveness data would &#xA;  be at hand; however, it is not consistently available. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and also in a scientific - practical sense:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;there are important distinctions &#xA;  between filterable and condensable PM2.5. Further, some &#xA;  methods used to measure PM emissions reflect only the &#xA;  filterable components and, to exacerbate the problem, the &#xA;  filterable components vary depending on the test method &#xA;  used. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The first step in any attempts to mitigate the FPM content in the air is to monitor the sources, flow, composition etc of the particles.  From the EPA document:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The importance of determining source apportionment &#xA;  for ambient PM2.5 in a specific area cannot be overstated; &#xA;  &lt;strong&gt;developing a cost-effective approach to controlling PM2.5&#xA;  emissions sources requires an understanding of the relative &#xA;  contribution from local and regional sources.&lt;/strong&gt; Adequate &#xA;  monitoring data are needed to provide insight into the &#xA;  composition of ambient PM2.5 in a given area. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A British document &lt;a href=&quot;http://uk-air.defra.gov.uk/assets/documents/reports/cat11/1212141150_AQEG_Fine_Particulate_Matter_in_the_UK.pdf&quot;&gt;Fine Particulate Matter &#xA;(PM2.5) in the United &#xA;Kingdom&lt;/a&gt; (2012), states the reason why action is not happening fast enough reasonably well, with&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The science underpinning the knowledge of PM2.5 is rapidly evolving and &#xA;  remains uncertain in many areas. There is a need for rapid translation into the &#xA;  policy arena of the newest results and understanding.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The uncertainty due to the varying compositions, which in turn affect how the particles move, how they interact with the surrounding environment suggests that 1 method would not be sufficient, and that more localised methods of control are necessary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you suggested, the importance of understanding FPM can not be understated, in epidemiological research &lt;a href=&quot;http://www.scientificintegrityinstitute.org/AJRCCM031506.pdf&quot;&gt;Reduction in Fine Particulate Air Pollution&#xA;and Mortality&#xA;Extended Follow-up of the Harvard Six Cities Study&lt;/a&gt; (Laden et al. 2006), there have been found to be a drop in mortality corresponding to a drop in FPM concentrations.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-11-12T20:02:58.573" LastActivityDate="2014-11-12T20:02:58.573" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2785" PostTypeId="1" CreationDate="2014-11-13T03:34:21.130" Score="3" ViewCount="826" Body="&lt;p&gt;Is it possible to measure the strength of a rare earth magnet to determine latitude and longitude of a current position? For instance say you start with your known latitude and longitude and then use a compass, accelerometer or other sensor besides a GPS to get your coordinates. What sensors would make the most sense? What equations would you use to keep track of your location based upon a fixed point in space? &lt;/p&gt;&#xA;" OwnerUserId="1117" LastEditorUserId="6784" LastEditDate="2016-10-14T18:39:11.853" LastActivityDate="2016-10-14T18:39:11.853" Title="Determine Latitude and Longitude without a GPS" Tags="|measurements|" AnswerCount="0" CommentCount="3" ClosedDate="2014-11-13T20:09:18.843" ContentLicense="CC BY-SA 3.0" />
  <row Id="2786" PostTypeId="2" ParentId="2778" CreationDate="2014-11-13T06:31:16.710" Score="14" Body="&lt;p&gt;First of all, Earth is not a random assortment of atoms. While it probably formed along like that in the beginning, somewhere along the way it differentiated into distinct core, mantle and crust, which are not chemically the same. That's a story for another question though, and there is an &lt;a href=&quot;https://earthscience.stackexchange.com/q/562/725&quot;&gt;excellent answer&lt;/a&gt; to it on this site.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Back to your question, &lt;strong&gt;Why are there ore deposits?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in addition to the Wikipedia quote given by farrenthorpe, here are some more (hopefully easily digestible) points:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Chemical elements posses differing properties. Even if you take a random mix of all elements in the periodic table, each and every one of them will have different properties. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Imagine a homogenous pile of gold and salt. Now, start pouring water over it, let it flow to a specific place and wait until the water dries and evaporates. Exploiting the different chemical properties of Au and NaCl, you've created two &quot;ore deposits&quot;, one of gold and the other of salt. In the Earth, there are a multitude of processes resulting from all kinds of combinations of temperature, pressure, fluid chemistry, magma processes and more, that facilitate selective concentration of certain elements over other elements.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are interested, here are some answers regarding the deposit formation of &lt;a href=&quot;https://earthscience.stackexchange.com/a/2397/725&quot;&gt;gold&lt;/a&gt; and &lt;a href=&quot;https://earthscience.stackexchange.com/a/2762/725&quot;&gt;rare earth elements&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-11-15T08:44:05.973" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2787" PostTypeId="2" ParentId="2771" CreationDate="2014-11-13T09:11:27.263" Score="5" Body="&lt;p&gt;Here are two parts of an answer, but this is by no means complete.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Most monsoonal research is focused on explaining the monsoonal passage through the plains of the Indian subcontinent. Very few papers can be found on how the same troughs cause rainfall at 3000 meters. I would like an authoritative reference on Monsoonal Mountain Meteorlogy. All that is known is that the MJO (BSISO) troughs and ridges at the 850 hPa seem to be damped at the Himalayan foothills. &lt;/li&gt;&#xA;&lt;li&gt;Regarding the 500 hPa propagating downwards I cannot get further more information than introducing the concept of a downward propagating Rossby wave. &#xA;And as  far as the physics that explains what happens when these two disparate systems meet it is at best an open research topic. &lt;/li&gt;&#xA;&lt;li&gt;I have read recent discussions(no reference available yet) that the two systems may need to &quot;line up&quot; in other words the geometric center of the upper level system needs to pass through the center of the lower level trough.Very recently Tropical Cyclone Hudhud moved up northwards towards the Himalayas and caused a blizzard in Nepal. There was a corresponding mid latitude disturabance at around the same time over the western Himalayas but extraordinary damage was prevented because the two systems did not line up.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;What is of more serious concern is the fact that there have been four such incidents in recent times - 1) Pakistan Floods 2010 2) North Indian Floods 2013. 3) Indian Pakistan floods of 2014. 4) The near miss with Cyclone Hudhud. &#xA;What climatic changes are causing  these collisions between disparate systems is a new field of study. Both weather and climate models will be stretched to predict these sort of collisions. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2014-11-16T08:50:33.337" LastActivityDate="2014-11-16T08:50:33.337" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2788" PostTypeId="2" ParentId="2781" CreationDate="2014-11-13T14:37:15.537" Score="11" Body="&lt;p&gt;For all intents and purposes, the Earth represents one frame of reference, as @kwinkunks states. Therefore no effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes the gravitational field on top of a mountain is slightly less than at sea level. This is very small though. Variations in gravity over the Earth's surface typically vary at most by a few hundred milligals (ie. &quot;one part in 10,000&quot; order of magnitude).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I doubt you would be able to measure General Relativistic effects due to such small field changes (even integrated over 10,000 years) - and even if you could, they are much smaller than other sources of error (e.g. the atmospheric C14 curve, and sampling errors).&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2014-11-13T14:37:15.537" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2789" PostTypeId="1" AcceptedAnswerId="4215" CreationDate="2014-11-13T14:51:09.090" Score="17" ViewCount="462" Body="&lt;p&gt;What is the accepted methodology to predict future climatic extremes using the results of climate models?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have recently read a report about &lt;strong&gt;climatic extremes considering climate change&lt;/strong&gt; (MICE, 2002). The report says that researchers fitted extreme value distributions (&lt;a href=&quot;http://en.wikipedia.org/wiki/Generalized_extreme_value_distribution&quot; rel=&quot;nofollow noreferrer&quot;&gt;generalized extreme value&lt;/a&gt;, &lt;a href=&quot;http://en.wikipedia.org/wiki/Generalized_Pareto_distribution&quot; rel=&quot;nofollow noreferrer&quot;&gt;generalized Pareto&lt;/a&gt;) to the intensity of predicted, future climatic actions, e.g. rain, snow, wind. Applying these models, events with a large &lt;a href=&quot;http://en.wikipedia.org/wiki/Return_period&quot; rel=&quot;nofollow noreferrer&quot;&gt;return period&lt;/a&gt; are used to assess the impact of climate change. Additionally, there is a recent Nature article by O’Gorman which also deals with future extreme events, particularly snow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Considering that the predictions (projections per scenarios) can be made only in probabilistic terms. I would like to know how these predictions are made, what methodology are they using? I mean the actual climatic data, not the extreme value (statistical) analysis of them. For extreme value analysis, annual or more frequent maxima can/could be used. It is quite dubious that climate models would predict monthly or annual maxima of rain/snow for a certain region, up to the end of this century (or are climate models so sophisticated?).&#xA;Someone told me that on this site (&lt;a href=&quot;http://esgf-data.dkrz.de/esgf-web-fe/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth System Grid Federation&lt;/a&gt;) there is an example of daily predicted snow data (this can be downloaded).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, my main question is &lt;strong&gt;how this data, these predictions, are produced. What are the underlying assumptions of the models?&lt;/strong&gt; Can these 100-year long simulations be used to predict extreme events within a 100 to 1000 year return period (these are common in engineering practice).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as I know, the climate models contain 'accurate' models (where the phenomenon is described by differential equations) and 'approximate' models (where empirical models are used). I guess the actual amount of precipitation for a given region belongs to the latter; in this case how uncertain are these models? (Surely the 'accurate' models have large uncertainty as well, but perhaps less).&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;I have an engineering background and I am interested in the effect of extreme climatic events on the reliability of structures; especially considering climate change. In order to study this, it would be great to know how reliable are the climate predictions regarding extreme events. If the probability distribution (or more complex probabilistic model of the actions) is given, the reliability of a structure (system) can be directly calculated. However, I am quite suspicious about the extremes predicted by the climate models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is quite hard to navigate through the thousand pages reports and find the probably one page long section which would answer my question. I would highly appreciate if someone could explain the main aspects of methodology, basic assumptions or point me to specific references, any help regarding the original question is welcomed.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;MICE (2002). &lt;a href=&quot;http://www.cru.uea.ac.uk/projects/mice/mice.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Modelling the Impact of Climate Extremes&lt;/a&gt;. Description of Work&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Paul A. O’Gorman. (2014). &lt;a href=&quot;http://www.nature.com/nature/journal/v512/n7515/full/nature13625.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Contrasting responses of mean and extreme snowfall to climate change&lt;/a&gt;. Nature. Volume 512. 7515.  p. 416-418.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Extension of the question:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/4248/can-climate-models-reliably-predict-meteorological-extremes&quot;&gt;Can climate models reliably predict meteorological extremes?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1121" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-05-01T02:09:46.330" Title="What is the methodology to analyze future climatic extremes using the results of climate models?" Tags="|meteorology|climate-change|precipitation|climate-models|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2790" PostTypeId="1" AcceptedAnswerId="2793" CreationDate="2014-11-13T17:31:31.510" Score="31" ViewCount="43477" Body="&lt;p&gt;We see tropical cyclones (going by different names e.g. hurricane, typhoon, cyclone) all over the tropics, but it seems that there are never any storms in the southern Atlantic.  See this map of tropical cyclone activity and note the lack of activity in the south Atlantic and also in the south Pacific until you near Australia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Vp0Xs.gif&quot; alt=&quot;tropical cyclone map&quot;&gt;&lt;br/&gt;&#xA;&lt;sub&gt;&#xA;&lt;a href=&quot;http://www.ec0.today/news/articleView.html?idxno=39&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;&#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Where are all the tropical cyclones in the southern Atlantic basin?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="330" LastEditorUserId="111" LastEditDate="2015-02-25T03:57:41.293" LastActivityDate="2019-09-07T19:58:56.723" Title="Why are there no hurricanes in the southern Atlantic basin?" Tags="|meteorology|tropical-cyclone|atlantic|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2791" PostTypeId="2" ParentId="2790" CreationDate="2014-11-13T17:41:32.517" Score="6" Body="&lt;p&gt;The original question asked why there were no hurricanes in the southern hemisphere.  The answer given:&lt;/p&gt;&#xA;&lt;p&gt;It really is just a naming convention based on location.  You can see in the wikipedia article here: &lt;a href=&quot;http://en.wikipedia.org/wiki/Tropical_cyclone#Classifications.2C_terminology.2C_and_naming&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://en.wikipedia.org/wiki/Tropical_cyclone#Classifications.2C_terminology.2C_and_naming&lt;/a&gt; , it says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Tropical cyclones are classified into three main groups, based on intensity: tropical depressions, tropical storms, and a third group of more intense storms, whose name depends on the region. For example, if a tropical storm in the Northwestern Pacific reaches hurricane-strength winds on the Beaufort scale, it is referred to as a typhoon; if a tropical storm passes the same benchmark in the Northeast Pacific Basin, or in the North Atlantic, it is called a hurricane. Neither &amp;quot;hurricane&amp;quot; nor &amp;quot;typhoon&amp;quot; is used in either the Southern Hemisphere or the Indian Ocean. In these basins, storms of a tropical nature are referred to as either tropical cyclones, severe tropical cyclones or very intense tropical cyclones.&lt;/p&gt;&#xA;&lt;p&gt;... each basin uses a separate system of terminology, which can make comparisons between different basins difficult. In the Pacific Ocean, hurricanes from the Central North Pacific sometimes cross the 180th meridian into the Northwest Pacific, becoming typhoons (such as Hurricane/Typhoon Ioke in 2006); on rare occasions, the reverse will occur.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-11-14T04:15:56.777" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2792" PostTypeId="2" ParentId="2781" CreationDate="2014-11-13T19:29:19.933" Score="7" Body="&lt;p&gt;Also please note the important difference between &lt;a href=&quot;http://en.wikipedia.org/wiki/Gravity_wave&quot;&gt;Gravity waves&lt;/a&gt; which come from hydrodynamics, and which you apparently refer to, when saying &quot;gravitational waves ripple across the face of this planet every day&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is ofc not true, as the waves that contribute to energy transport in the atmosphere are &lt;strong&gt;not&lt;/strong&gt; the &lt;em&gt;gravitational waves&lt;/em&gt; from general relativity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some astrophysicists would be really happy, if what you state were true, namely that gravitational waves can alter the decay time of atoms &lt;em&gt;measurably&lt;/em&gt;.&#xA;This is in fact not the case, why projects like &lt;a href=&quot;http://en.wikipedia.org/wiki/Laser_Interferometer_Space_Antenna&quot;&gt;LISA&lt;/a&gt; and other projects on earth have been set up to detect gravitational waves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also the proposed wavelengths of gravitational waves are so huge, that earth would only experience the wave near-uniformly with differential effects (that lead to measurability) being ever smaller.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2014-11-13T19:29:19.933" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2793" PostTypeId="2" ParentId="2790" CreationDate="2014-11-13T19:58:24.880" Score="22" Body="&lt;p&gt;There have been tropical storms and hurricanes in the south Atlantic, with, according to NOAA's webpage &lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/G6.html&quot; rel=&quot;noreferrer&quot;&gt;Subject: G6) Why doesn't the South Atlantic Ocean experience tropical cyclones?&lt;/a&gt;, with a hurricane forming in the south Atlantic making landfall in Brazil in 2004 and a strong tropical depression/weak tropical storm that formed off the coast of Congo in 1991 - but these are exceedingly rare.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason why these storms generally don't occur in the south Atlantic, according to the Penn State webpage &lt;a href=&quot;https://courseware.e-education.psu.edu/public/meteo/upperlevel_lows.html&quot; rel=&quot;noreferrer&quot;&gt;Upper-level Lows&lt;/a&gt; as being:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;There are two primary reasons why tropical cyclones are rare in the south Atlantic basin. First, vertical wind shear between 850 mb and 200 mb is typically greater than 10 meters per second (check out the long-term average of vertical wind shear between 850 mb and 200 mb). To make matters worse, westerly shear dominates over latitudes where tropical cyclones would be most likely to form. Second, easterly waves from Africa do not form south of the equator (the MLAEJ is a northern hemispheric singularity.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Further, from the NASA News page &lt;a href=&quot;http://science.nasa.gov/science-news/science-at-nasa/2004/02apr_hurricane/&quot; rel=&quot;noreferrer&quot;&gt;The Nameless Hurricane&lt;/a&gt;, they provide an extension to the explanation with&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Vertical wind shears in the south Atlantic are too strong for hurricanes,&quot; Hood explains. Winds in the upper troposphere (about 10 km high) are 20+ mph faster than winds at the ocean surface. This difference, or shear, rips storms apart before they intensify too much&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;An article &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2005GL023390/full&quot; rel=&quot;noreferrer&quot;&gt;The first South Atlantic hurricane: Unprecedented blocking, low shear and climate change&lt;/a&gt; (Pezza and Simmonds, 2005) suggest that the implications of the southern hemisphere hurricane presents&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;evidence to suggest that Catarina could be linked to climate change in the SH circulation, and other possible future South Atlantic hurricanes could be more likely to occur under global warming conditions.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Catarina refers to the southern hemisphere hurricane&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;SH = Southern Hemisphere&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;edited to add an &lt;a href=&quot;http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=12935&quot; rel=&quot;noreferrer&quot;&gt;NASA Earth Observatory&lt;/a&gt; satellite image of the hurricane:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Z3EMC.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-12-08T07:44:24.780" LastActivityDate="2014-12-08T07:44:24.780" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2794" PostTypeId="2" ParentId="2753" CreationDate="2014-11-13T21:28:38.177" Score="10" Body="&lt;p&gt;No, we do not need to stop extracting petroleum, we need to stop burning petroleum, as well as other fossil fuels, because combustion converts solid C to gaseous C, and hence goes up to the atmosphere, increasing the amount of greenhouse gases that warm the planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No, we do not need to convert existing CO&lt;sub&gt;2&lt;/sub&gt; into diamonds. Plants are pretty good taking up CO&lt;sub&gt;2&lt;/sub&gt; from the atmosphere, and storing the C as wood, that goes later into the soil as plant litter, where it can be stored long-term (and over millions of years may even become diamonds, petroleum or coal!). There are C losses as CO&lt;sub&gt;2&lt;/sub&gt; into the atmosphere, via either plant or soil respiration, but that is another wide topic. To be more precise, terrestrial plants and oceans remove each year more than half of the CO&lt;sub&gt;2&lt;/sub&gt; we emit into the atmosphere, for free!&lt;/p&gt;&#xA;" OwnerUserId="1125" LastEditorUserId="725" LastEditDate="2014-12-18T07:02:44.143" LastActivityDate="2014-12-18T07:02:44.143" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2795" PostTypeId="1" AcceptedAnswerId="2878" CreationDate="2014-11-14T05:00:35.913" Score="10" ViewCount="288" Body="&lt;p&gt;Is there any evidence of external material source events, like the 'Late Veneer' on other planets? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or is this theory specific just for Earth? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note, that this question may be related to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/96/how-and-why-did-the-oceans-form-on-earth-but-not-on-other-planets&quot;&gt;How and why did the oceans form on Earth but not on other planets?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But this is question is not water specific, or chondrite specific. &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-11-22T09:28:57.090" Title="'Late Veneer' on other planets" Tags="|earth-history|planetary-science|meteorite|planetary-formation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2796" PostTypeId="2" ParentId="2781" CreationDate="2014-11-14T06:55:27.223" Score="11" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;How do archaeologists address time dilation when analyzing carbon dating results?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They don't. There is &lt;strong&gt;NO&lt;/strong&gt; point in doing so. Compare two hypothetical substances at the peak of Chimborazo (the highest peak in the world with respect to distance from the center of the Earth). Suppose one of those substances spent all of the last 4.5 billion years at several thousand meters above sea level, while the other spent almost all of the last 4.5 billion years at the center of the Earth before migrating to the top of Chimborazo. That's the very worst time dilation possible. The substance that spent almost all of its earthly existence at the center of the Earth will be a couple of days younger than the other substance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That couple of days difference over a span of 4.5 billion years is the worst case. This is many orders of magnitude smaller than the statistically significant experimental errors. The error induced by relativistic effects with respect to carbon dating is unmeasurably small.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2014-11-14T07:00:38.040" LastActivityDate="2014-11-14T07:00:38.040" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2797" PostTypeId="2" ParentId="2287" CreationDate="2014-11-14T07:31:13.663" Score="5" Body="&lt;p&gt;CO&lt;sub&gt;2&lt;/sub&gt; can only enhance plant growth when other resources such as nutrients or water are not limiting growth. If N for instance is scarce, no matter how much you increase CO&lt;sub&gt;2&lt;/sub&gt;, plants will not take advantage of the increased CO&lt;sub&gt;2&lt;/sub&gt; concentration.&lt;/p&gt;&#xA;" OwnerUserId="1125" LastEditorUserId="725" LastEditDate="2014-12-10T07:03:02.997" LastActivityDate="2014-12-10T07:03:02.997" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2798" PostTypeId="2" ParentId="966" CreationDate="2014-11-14T10:25:05.520" Score="5" Body="&lt;p&gt;According to the State Climate Office of North Carolina webpage &lt;a href=&quot;http://www.nc-climate.ncsu.edu/climate/patterns/PDO.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Patterns - Pacific Decadal Oscillation (PDO)&lt;/a&gt;, experts believe&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the PDO can intensify or diminish the impacts of ENSO according to its phase. If both ENSO and the PDO are in the same phase, it is believed that El Niño/La Niña impacts may be magnified. Conversely, if ENSO and the PDO are out of phase, it has been proposed that they may offset one another, preventing &quot;true&quot; ENSO impacts from occurring.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Essentially, almost analogous to constructive and destructive interference in sound.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another relationship, from the University of Alaska, Fairbanks webpage &lt;a href=&quot;http://ffden-2.phys.uaf.edu/645fall2003_web.dir/Jason_Amundson/enso.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Pacific Decadal Oscillation&lt;/a&gt; also asserts that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A positive, or warm phase PDO, produces climate and circulation patterns that are very similar to El Niño. Likewise, a negative, or cool phase PDO, produces climate and circulation patterns similar to La Niña (Gershunov and Barnett, 1998).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As can be seen in the image below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/rgpbI.jpg&quot; alt=&quot;enter image description here&quot;&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/6uRFl.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image source: &lt;a href=&quot;http://jisao.washington.edu/pdo/graphics.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pacific Decadal Oscillation (PDO) Graphics&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The consequences for forecasting are summed up by the NASA News web-article &lt;a href=&quot;http://science.nasa.gov/science-news/science-at-nasa/2003/14mar_elnino2002/&quot; rel=&quot;nofollow noreferrer&quot;&gt;A Quirky El Niño&lt;/a&gt; as being the case&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If El Niño begins during a cool phase of the PDO, El Niño tends to be milder and less predictable. El Niños that come during a warm PDO are stronger and &quot;better behaved, in the sense that we can predict their consequences&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gershunov, A. and T.P. Barnett. Interdecadal modulation of ENSO teleconnections. Bulletin of the American Meteorological Society, 79(12): 2715-2725.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="111" LastEditDate="2014-12-21T21:43:39.517" LastActivityDate="2014-12-21T21:43:39.517" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2799" PostTypeId="1" AcceptedAnswerId="2808" CreationDate="2014-11-14T13:44:25.923" Score="5" ViewCount="651" Body="&lt;p&gt;Certain maritime ports and airports have ranges of operation relation to the wind, usually according to a given threshold value of sustained wind speed. If I have the instantaneous values from anemometer every 50 seconds, how can I determine that the sustained wind speed exceeded the threshold?&lt;/p&gt;&#xA;" OwnerUserId="1128" LastEditorUserId="192" LastEditDate="2014-11-15T18:28:23.837" LastActivityDate="2014-11-15T18:28:23.837" Title="How to determine that sustained wind speed exceeded the threshold value?" Tags="|meteorology|measurements|wind|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2800" PostTypeId="2" ParentId="2427" CreationDate="2014-11-14T21:38:48.483" Score="-3" Body="&lt;p&gt;My current understanding is that, while the trend over hundreds of thousands of years has not (yet?) been significantly deviated from, the &lt;em&gt;rate&lt;/em&gt; at which the temperature has been rising over the last 100 years has been unprecedented* (I concluded its not in fact unprecedented, see below).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not entirely sure that the rate &lt;em&gt;is&lt;/em&gt; in fact unprecedented, but I could certainly see it being that way. Look at the graphs at &lt;a href=&quot;https://en.wikipedia.org/wiki/Temperature_record&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Temperature_record&lt;/a&gt; , it looks like:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Between about 14 thousand years ago and 7 thousand years ago, the temperature rose by 8 degrees, which is 1.15 degrees per 1000 years on average.&lt;/li&gt;&#xA;&lt;li&gt;Between 132 thousand years ago and 124 thousand years ago, the temperature rose by about 14 degrees, which is a  1.75 degree per 1000 years on average.&lt;/li&gt;&#xA;&lt;li&gt;In the last 100 years, the temperature has increased on average about 1.1 degrees. So that's a good 11 degrees per thousand years, which is about 6 times what looks like one of the highest rates on the long term ice core record.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So because of the different lengths of times, and different scales, its a certainty that there was variance in the rate of temperature change between 132 thousand years ago and 124 thousand years ago. This means that there were definitely spans of 100 years in the those few thousand years in which the rate of increase was greater than the average.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So this lead me to looking at the actual data the graph on wikipedia was derived from. Here's the source: &lt;a href=&quot;ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/epica_domec/&quot; rel=&quot;nofollow&quot;&gt;ftp://ftp.ncdc.noaa.gov/pub/data/paleo/icecore/antarctica/epica_domec/&lt;/a&gt; . Looking specifically at the spreadsheet called edc3deuttemp2007.xls , I see that indeed between between 132 thousand years ago and 124 thousand years ago, there are about 12 approximately hundred-year periods with greater than a 1.1 degree increase per hundred years. I took periods of three data points, which means they're not all the same exact length of time. In any case, this was from 76 3-data-point periods, so a full 15% of the time periods in that section of the data had greater temperature growth than we've seen in the last 100 years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact, since 133 thousand years ago, there have been over 150 non-overlapping 100-year periods where the temperature has been rising faster than it has in the last 100 years. This is about 11% of the 100-year periods in the last 133 thousand years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in conclusion, based on this data, I have to conclude that the rate of temperature rise in the last 100 years is certainly not unprecedented, and thus my question still stands: why is this not compelling evidence that the temperature rise is largely not anthropogenic?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are the calculations I added to the spreadsheet to come to my conclusions: &lt;a href=&quot;http://www.btetrud.com/files/edc3deuttemp2007%20-%20annotated%20with%20~100%20year%20temp%20diffs.xls&quot; rel=&quot;nofollow&quot;&gt;http://www.btetrud.com/files/edc3deuttemp2007%20-%20annotated%20with%20~100%20year%20temp%20diffs.xls&lt;/a&gt; . Note that the data is all in the second spreadsheet tab (the 'data' tab).&lt;/p&gt;&#xA;" OwnerUserId="838" LastEditorUserId="838" LastEditDate="2014-11-19T05:12:36.280" LastActivityDate="2014-11-19T05:12:36.280" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="2801" PostTypeId="2" ParentId="2427" CreationDate="2014-11-14T22:28:30.337" Score="7" Body="&lt;p&gt;No, ice cores do not refute human-caused warming.  In fact, they support it.  Your logic really doesn't follow because the rate of warming now compared to some arbitrary previous date is not  related to whether the warming is driven by humans.  Instead, it is important to consider the natural variation of physical factors that affect climate (collectively known as Malenkovitch cycles; &lt;a href=&quot;http://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://en.wikipedia.org/wiki/Milankovitch_cycles&lt;/a&gt; ), and then recognize any large deviations from those cycles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An image of the EPICA and Vostok ice cores versus age obtained from &lt;a href=&quot;http://en.wikipedia.org/wiki/Ice_age&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://en.wikipedia.org/wiki/Ice_age&lt;/a&gt; , clearly shows influence of the Malenkovitch cycles.  The most notable of which is the strong cycle that is approximately 70,000 years and is associated with geologic ice ages. In fact, the Earth is historically on average much cooler than it is now, and the retreat of glaciers has been periodic but not sustained.  We were supposed to have cooled off some time ago, but clearly we are not in a global cooling period. Many would even argue that humans started affecting the climate over 7,000 years ago when land management and fire was wielded prevalently.&lt;br&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/mw7QG.png&quot; alt=&quot;EPICA and VOSTOK Cores&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to attribute climate change to humans, climate models are run with and without anthropogenic climate forcing.  When they do so, climate models run without anthropogenic forcing are unable to duplicate the current warming trend.  I've attached an image of this from the IPCC AR5 Technical Summary draft which shows a full climate simulation, one without anthropogenic climate forcers, and one with no aerosol forcing for comparison.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/e7cus.png&quot; alt=&quot;climate model results for history&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, I thought someone might value this link that discusses climate change atrribution:&#xA;&lt;a href=&quot;http://www.realclimate.org/index.php/archives/2014/08/ipcc-attribution-statements-redux-a-response-to-judith-curry/comment-page-4/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.realclimate.org/index.php/archives/2014/08/ipcc-attribution-statements-redux-a-response-to-judith-curry/comment-page-4/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2014-11-15T05:08:30.297" LastActivityDate="2014-11-15T05:08:30.297" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="2802" PostTypeId="2" ParentId="421" CreationDate="2014-11-15T06:04:17.477" Score="8" Body="&lt;p&gt;One thing that I would add is a discussion of a physical parameter that is a simple measure of whether a wave is going to topple or not. The Froude number is defined as the ratio of the maximum absolute fluid velocity, $U$, and the wavespeed, $c$:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$F = U/c$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because of the mechanism explained by IRO-bot,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In shallow water, the water particles near the crest move forward faster than those below them. Similarly, the particles near the trough move backward faster than those above them. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;the highest velocities are encountered at the top of the wave and therefore a good rule of thumb is, if the surface fluid velocity aproaches the wave speed, i.e $F \to 1$, then the wave will topple over.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question is what values of $F$ give rise to that perfect tube feeling that surfers yearn for and so perfectly exemplified by your picture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, since $F &amp;gt; 1$ implies that the wave amplitude is large, linear theory is no longer helpful. We may have to wait until we can get some definite answers from DNS 3D simulations of oceanic scale wave breaking phenomena.&lt;/p&gt;&#xA;" OwnerUserId="200" LastActivityDate="2014-11-15T06:04:17.477" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2803" PostTypeId="1" AcceptedAnswerId="3159" CreationDate="2014-11-15T07:37:58.313" Score="12" ViewCount="481" Body="&lt;p&gt;In an earlier question/answer &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2790/why-are-there-no-hurricanes-in-the-southern-atlantic-basin&quot;&gt;Why are there no cyclones in the southern Atlantic basin&lt;/a&gt; there was a point raised about direction of              shear(abetting/retarding) cyclone formation. It appears westerly shear hinders the formation of tropical cyclones and easterly shear enhances it. This should mean that cyclone formation is only allowed over monsoonal regions. Is that accurate ? From this article - &lt;a href=&quot;http://www.cwb.gov.tw/V7/climate/climate_info/information/lectures/14/Lecture_1_Wave_and_Response.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tropical wave dynamics and Heatinduced&#xA;steady response&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;it appears that in the presence of westerly shear Rossby waves have large amplitude at the upper troposphere whereas in the presence of easterly shear Rossby waves have large amplitude in the lower troposphere. Given that the precursors of tropical cyclones are equatorial waves can a clarification be provided in this regard ? &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-02-25T05:22:17.513" LastActivityDate="2019-02-25T05:22:17.513" Title="Relation between direction of shear and tropical cyclone formation" Tags="|meteorology|tropical-cyclone|atmospheric-circulation|troposphere|" AnswerCount="1" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="2804" PostTypeId="1" AcceptedAnswerId="2847" CreationDate="2014-11-15T09:52:05.777" Score="8" ViewCount="149" Body="&lt;p&gt;As answered in my earlier question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2750/how-much-methane-clathrates-are-buried-in-continental-deposits&quot;&gt;How much methane clathrates are buried in continental deposits?&lt;/a&gt;, there is alot of methane trapped in the form of clathrates in continental deposits.  Additionally, according to the National Snow and Ice Data Centre webpage &lt;a href=&quot;https://nsidc.org/cryosphere/frozenground/methane.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Methane and Frozen Ground&lt;/a&gt; states that the&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;estimate that there are about 1,400 gigatons of carbon frozen in permafrost.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;According to the webpage, this is &lt;em&gt;more&lt;/em&gt; than exists in the atmosphere, but it is unlikely to be released at once (due to depth, local conditions etc).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The recent IPCC &lt;a href=&quot;http://www.ipcc.ch/pdf/assessment-report/ar5/syr/SYR_AR5_SPM.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;5th Assessment Report&lt;/a&gt; stated that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Without additional efforts to reduce GHG emissions beyond those in place today, global emissions growth is &#xA;  expected to persist, driven by growth in global population and economic activities. Global mean surface &#xA;  temperature increases in 2100 in baseline scenarios – those without additional mitigation – range from 3.7 to &#xA;  4.8°C above the average for 1850-1900 for a median climate response.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(GHG = Greenhouse gases)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They also state, in regards to permafrost,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It is virtually certain that near-surface permafrost extent at high northern latitudes will be reduced as global &#xA;  mean surface temperature increases, with the area of permafrost near the surface (upper 3.5 m) projected to &#xA;  decrease by 37% (RCP2.6) to 81% (RCP8.5)for the multi-model average (medium confidence).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What amount of permafrost carbon release could be expected with the IPCC worse-prediction of a 4.8C temperature rise?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(If any published studies are available, that would be good too).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Note: this carbon source is not explicitly covered in the question and answer for &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2755/how-is-carbon-distributed-among-the-atmosphere-the-oceans-the-biomass-and-the&quot;&gt;How is carbon distributed among the atmosphere, the oceans, the biomass and the unburnt fossil fuels?&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-12-18T07:14:13.200" Title="What amount of permafrost carbon release could be expected with the IPCC worse-prediction of a 4.8C temperature rise?" Tags="|global-warming|carbon|permafrost|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2805" PostTypeId="2" ParentId="272" CreationDate="2014-11-15T14:27:10.067" Score="2" Body="&lt;p&gt;Yes, there have been recent research in this field.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the article &lt;a href=&quot;http://www.pnas.org/content/96/7/3380.full.pdf&quot; rel=&quot;nofollow&quot;&gt;Oceanic minerals: Their origin, nature of their environment,&#xA;and significance&lt;/a&gt; (Kastner, 1999), who asserts that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The zeolites phillipsite and analcime mostly reflect on&#xA;  diagenesis of volcanic matter; &lt;strong&gt;clinoptilote and heulandite occur in Si-rich&#xA;  diagenetic environments.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and confirm that &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In addition to diagenetic opal-CT and quartz that&#xA;  form from the dissolution of biogenic opal-A, other common&#xA;  authigenic alumino-silicate minerals are smectites and zeolites.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is further confirmed by a 2007 paper &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0009254107003804&quot; rel=&quot;nofollow&quot;&gt;Clinoptilolite as a new proxy of enhanced biogenic silica productivity in lower Miocene carbonate sediments of the Bahamas platform: Isotopic and thermodynamic evidence&lt;/a&gt; (Karpoff et al) which determined that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Seawater–rock modeling specifies that clinoptilolite precipitates from the dissolution of biogenic silica, which reacts with clay minerals. The amount of silica (opal-A) involved in the reaction has to be significant enough, at least 10 wt.%, to account for the observed content of clinoptilolite occurring at the most zeolite-rich level. Modeling also shows that the observed amount of clinoptilolite (∼ 19%) reflects an in situ and short-term reaction due to the high reactivity of primary biogenic silica (opal-A) until its complete depletion.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-11-15T14:27:10.067" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2806" PostTypeId="1" CreationDate="2014-11-15T16:01:00.707" Score="11" ViewCount="855" Body="&lt;p&gt;I'm a computer/atmospheric science undergrad and I'm trying to get into atmospheric modeling. Any recommendations for resources to get going or to learn about approaches? I can handle fairly technical stuff so don't be shy.&lt;/p&gt;&#xA;" OwnerUserId="1129" LastEditorUserId="64" LastEditDate="2014-11-15T17:44:10.013" LastActivityDate="2014-11-15T17:44:10.013" Title="Resources for learning the technical parts of atmospheric modeling" Tags="|meteorology|atmosphere|models|numerical-modelling|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2807" PostTypeId="2" ParentId="2806" CreationDate="2014-11-15T17:23:56.100" Score="14" Body="&lt;p&gt;For fundamentals on numerical methods applied in atmosphere and ocean modeling, see the GARP publication by Mesinger and Arakawa: &lt;a href=&quot;http://twister.caps.ou.edu/CFD2013/Mesinger_ArakawaGARP.pdf&quot;&gt;Numerical Methods Used in Atmospheric Models&lt;/a&gt;. This old, but certainly not outdated text provides the basics on time and space discretization and stability, with particular focus on solving advection equations, and gravity-inertia wave (read: shallow water) equations, and is relatively easy to digest. A must read for any meteorologist or oceanographer using or developing numerical models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then, an excellent textbook by Dale Durran, &lt;a href=&quot;http://www.atmos.washington.edu/numerical_methods/&quot;&gt;Numerical Methods for Fluid Dynamics: with Applications in Geophysics&lt;/a&gt; maintains similar application focus as Mesinger and Arakawa, but expanded with more numerical algorithms and in-depth analysis. It covers the basics as well, so it can be used as a stand-alone text.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are many other more general CFD textbooks that contain material applicable to ocean and atmosphere modeling. The majority are more geared towards mechanical engineering applications, so you may need to apply a filter (hur hur).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, if you are more interested in physics parameterization schemes used in atmosphere models, such as cumulus convection, microphysics, or boundary layer parameterization schemes, a book by David Stensrud, &lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/0521126762&quot;&gt;Parameterization Schemes: Keys to Understanding Numerical Weather Prediction Models&lt;/a&gt;, is an excellent summary of current state-of-the-art. It covers a wide area of unresolved physical processes in the atmosphere, so it does not go into too many details - if you are interested in fully understanding a particular scheme, you will need to follow the reference chain and read the particular papers on the topic. I highly recommend this one if you are interested in gaining an overall understanding of parameterizing atmospheric physics processes.&lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2014-11-15T17:29:17.430" LastActivityDate="2014-11-15T17:29:17.430" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="2808" PostTypeId="2" ParentId="2799" CreationDate="2014-11-15T17:55:11.107" Score="5" Body="&lt;p&gt;You are essentially asking how to determine what the sustained wind speed is, and as pointed out in a comment, this is merely temporally averaging your 50 s instantaneous wind observations.  The specific application you are targeting likely has a standardized definition of a time period over which the averaging should occur.  This might be a 3 minute wind, a 5 minute wind or some other value.  Once you know this value, you can calculate a rolling average over your time series of instantaneous wind and this rolling average is your &quot;sustained&quot; wind.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If your application is aviation, you'll want to keep the sustained wind and the peak winds, as the difference between sustained and peak gust is important to landing aircraft (we call that difference the &quot;gust factor&quot; and is generally more important than the sustained wind alone).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;METAR define wind direction and speed as 2 minute averages and define gusts as a minimum 10 kt deviation over the mean during a 10 minute period. See  &lt;a href=&quot;http://www.met.tamu.edu/class/metar/metar-pg6.html#Wind%20Definitions&quot;&gt;this page&lt;/a&gt; for more information on observing wind for METAR applications.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2014-11-15T18:17:29.447" LastActivityDate="2014-11-15T18:17:29.447" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2809" PostTypeId="2" ParentId="689" CreationDate="2014-11-15T18:03:41.580" Score="6" Body="&lt;p&gt;&lt;strong&gt;Fast exhumation is not necessary to retain blueschist mineral assemblage.&lt;/strong&gt; This is the classical difference between prograde and retrograde metamorphism, and it's not limited to blueschists. Why do we have eclogite on Earth's surface? What about granulites? Amphibolites? In fact, why do we see any metamorphic rocks on the surface instead of just various clays and quartz?&lt;/p&gt;&#xA;&lt;p&gt;There are two main reasons for that.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Prograde metamorphism results in dehydration and loss of water&lt;sup&gt;(1)&lt;/sup&gt;. Most of the original water content of the rock was in various hydrous minerals, and as you progress in your metamorphic path you lose more and more water to dehydration reactions. While it is true that in blueschist waster can be retained in minerals such as lawsonite, phengite, epidote and glaucophane, most of it is still lost. If you want to reequilibrate the rock to its previous mineral assemblage, you need to reintroduce the water. This can occur occasionally, for instance in this classic example from Norway:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/el6e0.jpg&quot; alt=&quot;rehydration&quot; /&gt;&#xA;&lt;sup&gt;source: &lt;a href=&quot;http://www.geol.ucsb.edu/faculty/hacker/geo102C/lectures/part11.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.geol.ucsb.edu/faculty/hacker/geo102C/lectures/part11.html&lt;/a&gt;&lt;/sup&gt;&#xA;&lt;br&gt;...where a granulite was rehydrated along a joint to form eclogite, but it's usually very localised and uncommon.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Most prograde metamorphic reactions are exothermic, &lt;em&gt;i.e.&lt;/em&gt; they release heat. Retrograde reactions are usually endothermic. They require heat in order to proceed, but in the event of exhumation, temperatures are decreasing. There is simply not enough heat around to support the retrograde reactions. Furthermore, you have to remember that lower temperature also lowers the reaction kinetics.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;&lt;strong&gt;This doesn't mean that fast exhumation cannot occur...&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;There are pieces of evidence that in some cases exhumation can be even faster than the erosion rate&lt;sup&gt;(2)&lt;/sup&gt;. This suggest that orogenic events may also result from simple uplift and not only compression and folding. What causes the uplift? This may actually be the result of crustal thinning and extensional stress regimes, as in the examples of Liaodong&lt;sup&gt;(3)&lt;/sup&gt; and Brittany&lt;sup&gt;(4)&lt;/sup&gt;. This phenomenon is also known as a &lt;em&gt;core complex&lt;/em&gt;, where extensional tectonics result in low angle normal detachment faults that results in rapid unroofing and exposure deep seated rocks. You may be familiar with oceanic core complexes, so this processes is quite similar.&lt;/p&gt;&#xA;&lt;p&gt;&lt;br&gt;&lt;br&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;(1)&lt;/sup&gt; Forgive me for not including the zeolite facies in my definition of metamorphism.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;(2)&lt;/sup&gt; Rubatto, D., &amp;amp; Hermann, J. (2001). Exhumation as fast as subduction?. &lt;em&gt;Geology&lt;/em&gt;, 29(1), 3-6. &lt;a href=&quot;http://dx.doi.org/10.1130/0091-7613(2001)029%3C0003:EAFAS%3E2.0.CO;2&quot; rel=&quot;noreferrer&quot;&gt;10.1130/0091-7613(2001)029&amp;lt;0003:EAFAS&amp;gt;2.0.CO;2&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;(3)&lt;/sup&gt; Yang, J. H., Wu, F. Y., Chung, S. L., Lo, C. H., Wilde, S. A., &amp;amp; Davis, G. A. (2007). Rapid exhumation and cooling of the Liaonan metamorphic core complex: Inferences from &lt;sup&gt;40&lt;/sup&gt;Ar/&lt;sup&gt;39&lt;/sup&gt;Ar thermochronology and implications for Late Mesozoic extension in the eastern North China Craton. &lt;em&gt;Geological Society of America Bulletin&lt;/em&gt;, 119(11-12), 1405-1414. &lt;a href=&quot;http://dx.doi.org/10.1130/B26085.1&quot; rel=&quot;noreferrer&quot;&gt;10.1130/B26085.1&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;(4)&lt;/sup&gt; Brown, M., &amp;amp; Dallmeyer, R. D. (1996). Rapid Variscan exhumation and the role of magma in core complex formation: southern Brittany metamorphic belt, France. &lt;em&gt;Journal of Metamorphic Geology&lt;/em&gt;, 14(3), 361-379. &lt;a href=&quot;http://dx.doi.org/10.1111/j.1525-1314.1996.00361.x&quot; rel=&quot;noreferrer&quot;&gt;10.1111/j.1525-1314.1996.00361.x&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-11-17T12:22:49.030" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2810" PostTypeId="2" ParentId="2500" CreationDate="2014-11-16T09:16:20.377" Score="4" Body="&lt;p&gt;This is a part answer, as pinning down the actual date that the canal formed is not well framed in the literature.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the Texas A&amp;amp;M University web-chapter &lt;a href=&quot;http://aquaticecology.tamu.edu/files/2012/07/W-Willis-Ch14-Casiquiare.pdf&quot; rel=&quot;nofollow&quot;&gt;The Vaupes Arch and Casiquiare Canal Barriers and Passages &lt;/a&gt; (Winemiller and Willis, 2011), are quite vague about exactly pinning down the age of the canal, with&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Extensive alluvial sedimentation and channel &#xA;  meandering provided subsequent opportunities for drainage &#xA;  capture between the Orinoco and Negro headwaters to the &#xA;  east of the Vaupes Arch, and at some point the Río Casiquiare &#xA;  formed a connection between the upper Orinoco and upper &#xA;  Negro rivers&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and by using digital maps based on the topography suggest that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the upper&#xA;  Casiquiare course may have been captured quite recently by&#xA;  the Pasiba–Siapa–lower Casiquiare drainage network as a result&#xA;  of river meandering on the peneplain.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The article &lt;a href=&quot;http://deepblue.lib.umich.edu/bitstream/handle/2027.42/79059/j.1365-294X.2010.04540.x.pdf?sequence=1&amp;amp;isAllowed=y&quot; rel=&quot;nofollow&quot;&gt;The Casiquiare river acts as a corridor between&#xA;the Amazonas and Orinoco river basins: biogeographic&#xA;analysis of the genus Cichla&lt;/a&gt; (Willis et al. 2001) are more direct in stating that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Unfortunately, the precise timing of the origin of the&#xA;  Casiquiare remains unknown&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;also stating that in studies of the DNA of species in either basin, there seems to be little dispersal between them through the canal.  Specifically noting that the&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Casiquiare River acts as a selective filter, where only&#xA;  some species are able to make the transition from&#xA;  stained, acidic water in the Negro River to unstained,&#xA;  neutral water in the upper Orinoco River. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Winemiller et al. (2008) state in the article &lt;a href=&quot;http://aquaticecology.tamu.edu/files/2012/07/Winemiller-et-al-JBI-2008.pdf&quot; rel=&quot;nofollow&quot;&gt;Fish assemblages of the Casiquiare River,&#xA;a corridor and zoogeographical filter for&#xA;dispersal between the Orinoco and&#xA;Amazon basins&lt;/a&gt; (2009), that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Hydrologically, the&#xA;  Casiquiare represents a stream capture in progress, but there is&#xA;  some debate concerning its formation&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Secondly, an answer to your question as to why the water does not stay in the Orinoco, it is a question of elevation, according to Winemiller and Willis, (2011), it is a case of flowing downstream from the western edge of the Guiana Shield, the direction governed by the elevations of the two ends of the bifurcation.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;At its origin at the&#xA;  bifurcation of the upper Orinoco, the Casiquiare&#xA;  is about 90 m wide and lies at an &lt;strong&gt;elevation of 120 meters&#xA;  above sea level (m-asl)&lt;/strong&gt;. At its mouth at the upper Rio Negro,&#xA;  the Casiquiare is over 500 m wide at an &lt;strong&gt;elevation&#xA;  of about 90 m-asl.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and passes through what Winemiller et al. (2008) describe as an alluvium filled floodplain, that coupled with the meandering and stream capture (mentioned above) has governed the course of the canal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Rio Negro being a major tributary of the Amazon River.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lujan and Armbruster, authors of the chapter &lt;a href=&quot;http://www.auburn.edu/~armbrjw/Guiana_shield.pdf&quot; rel=&quot;nofollow&quot;&gt;The Guiana Shield&lt;/a&gt; (2011) assert that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In the &#xA;  future, it is likely that a new drainage divide will form within &#xA;  the Orinoco downstream of the Tama-Tama bifurcation, and &#xA;  the current headwaters of the Orinoco will become entirely &#xA;  adopted by the Amazon&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-11-16T09:43:32.437" LastActivityDate="2014-11-16T09:43:32.437" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2811" PostTypeId="1" AcceptedAnswerId="2819" CreationDate="2014-11-16T15:53:09.607" Score="11" ViewCount="227" Body="&lt;p&gt;I've had an inconclusive chat about the Sveconorwegian belt of the Fennoscandian shield, the western parts in particular, and reasons as to why there would not be any deposits of hydrocarbons there. Perhaps someone here can provide a definite answer?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it simply that the belt is of primarily Gothian origin, or might there be more to it?&lt;/p&gt;&#xA;" OwnerUserId="1131" LastEditorUserId="28050" LastEditDate="2014-11-17T18:38:39.903" LastActivityDate="2014-11-17T19:02:32.790" Title="Why would there be no hydrocarbons in the Sveconorwegian belt?" Tags="|precambrian|petroleum|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2812" PostTypeId="1" CreationDate="2014-11-16T17:02:35.127" Score="12" ViewCount="2097" Body="&lt;p&gt;I have tried to convert a Seismic SU file to ASCII format in seismic unix using openseaseis module named &quot;sutoascii&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;I have already tested the SU file by opening it in SeaView Seismic Viewer and then tried to convert it to &quot;ASCII&quot; format using the following command:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;sutoascii &amp;lt;inputSUFilename &amp;gt;outputASCIIFilename bare=0 index=1&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;The ASCII file is created as an output file but it gives an error while converting that &lt;strong&gt;&quot;number of samples in header differs from number for first trace&quot;&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now to check whether the Resulting ASCIIFile is valid and working, I have tried to open it in SeaView Seismic Viewer again to cross-check but it shows an error and is unable to open the file.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Can anybody tell me how to correct this?&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="1132" LastActivityDate="2015-02-13T18:00:25.077" Title="converting SU file to ASCII format in seismic unix using OpenSeaSeis" Tags="|geophysics|seismology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2813" PostTypeId="1" AcceptedAnswerId="4450" CreationDate="2014-11-16T17:03:51.067" Score="19" ViewCount="387" Body="&lt;p&gt;How do the web services exchange meteorological data? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One method is transferring NetCDF and GRIB data and hooking them up to your software.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I read &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1017/S1350482705001556/pdf&quot;&gt;here&lt;/a&gt; about the possibility of using WFS and WCS. &lt;a href=&quot;http://www.resc.rdg.ac.uk/publications/GADS_paper-rev-final.pdf&quot;&gt;Here&lt;/a&gt;, I read about the proposal of using calls like dataQuery, similar to getCapabilities of WMS servers. I &lt;a href=&quot;http://data.nasa.gov/api-info/&quot;&gt;also note&lt;/a&gt; that NASA uses JSON output, e.g. for the DCP-30 dataset. In Europe, the INSIPRE committee publishes &lt;a href=&quot;http://inspire.ec.europa.eu/index.cfm/pageid/2&quot;&gt;very complex guidelines&lt;/a&gt; . DWD, UK Met office and others &lt;a href=&quot;http://52north.org/home/events-in-2014/workshop-the-use-of-gis-ogc-standards-in-meteorology&quot;&gt;recently held a conference&lt;/a&gt; on that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a global standard and what is it? I know the OGC-DWG is working on that since 2009. What are the latest updates?&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Addendum (Full forms of Abbreviations)&lt;/h1&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;WMS : Web Mapping Service, a Server that responds with a map image of&#xA;a spacific area, or about its ability to serve. &lt;/li&gt;&#xA;&lt;li&gt;WCS : Web Coverage&#xA;Service, similar to above, but serves gridded data, e.g. temperature,&#xA;covering a continuous area. &lt;/li&gt;&#xA;&lt;li&gt;WFS : Web Feature Service, similar to&#xA;WCS, but serves features on an around a given point (or points) -&#xA;thus discreet, not continuous. &lt;/li&gt;&#xA;&lt;li&gt;DCP : Downsized Climate Projection, a&#xA;low resolution dataset projecting the future global climate. 30&#xA;indicates 30 years in future and so on. &lt;/li&gt;&#xA;&lt;li&gt;OGC : Open Geospatial&#xA;Consortium , a non profit organization standardizing geospatial data.&lt;/li&gt;&#xA;&lt;li&gt;DWG : Domain working Group, a workgroup in OGC specializing in a&#xA;particular field, one in this case for standardizing meteorological&#xA;and oceanographic data exchange.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="313" LastEditorUserId="313" LastEditDate="2014-11-17T13:35:42.533" LastActivityDate="2020-07-24T19:38:57.187" Title="What is the status of meteorological data exchange standards?" Tags="|meteorology|open-data|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2814" PostTypeId="1" CreationDate="2014-11-17T06:49:59.543" Score="16" ViewCount="13205" Body="&lt;p&gt;There are plenty of experiments, usually geared toward kids, that involve &quot;making a cloud in a bottle&quot; or something similar.  These exercises are neat for what they are, but pale in comparison to the beauty of real clouds.  Really you're just making fog in a bottle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using currently available (preferably consumer grade) technology, is it possible to create &lt;strong&gt;real&lt;/strong&gt; clouds?  Or even better, a real weather system?  Imagine you have an enclosed 10 ft wide cube.  If you build a landscape inside, complete with mountains and bodies of water, and you have complete control over the boundary conditions of the cube (temperature, airflow in/out, etc.), can you reproduce the beauty of a towering cumulus cloud inside the cube? One step further... can you create thunderstorms?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have a very rudimentary understanding of how weather works, but the engineer in me says in theory this should be possible.  But in reality a lot of small details glare out at me as possible show stoppers.  Aerodynamics does not scale, because of the constant size of air molecules at all scales.  I suspect this limitation may affect my weather system puzzle as well.  Also with respect to thunderstorms, I suspect the 10 ft wide cube may not be able to mimic the role of planetary grounding, atmosphere, etc., in the creation of electric discharges.&lt;/p&gt;&#xA;" OwnerUserId="1135" LastEditorUserId="662" LastEditDate="2015-01-14T15:09:17.177" LastActivityDate="2018-12-20T12:18:59.527" Title="Is it possible to create an enclosed manmade weather system?" Tags="|meteorology|laboratory|" AnswerCount="8" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2815" PostTypeId="2" ParentId="185" CreationDate="2014-11-17T07:29:00.110" Score="3" Body="&lt;p&gt;A major consideration for any such altitude measurement, hence determination of the factors is, according to &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2008JD009938/pdf&quot; rel=&quot;nofollow&quot;&gt;Turbopause determination, climatology, and climatic trends using&#xA;medium frequency radars at 52°N and 70°N&lt;/a&gt; (Hall et al. 2008), that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;measurement of the turbopause altitude is a rather different matter, primarily because direct measurements of small-scale fluctuations in neutral density, temperature or motion at altitudes of around 100km are virtually impossible. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The authors state that seasonal variation plays a significant role; the article &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S1364682607001320&quot; rel=&quot;nofollow&quot;&gt;The “wave turbopause”&lt;/a&gt; (Offerman et al. 2007) elaborate on this in their abstract:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Substantial seasonal and latitudinal variations are found, with some interannual variability also present. Seasonal changes are annual at high latitudes, semi-annual at low latitudes, and a mixture of both at middle latitudes. Southern hemisphere data are similar as in the North if shifted by half a year. Latitudinal variations show a minimum in the tropics and two relative maxima at middle latitudes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;With observations made in northern Norway in the article &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/1998JD200002/pdf&quot; rel=&quot;nofollow&quot;&gt;Seasonal variation of the turbopause' One year of turbulence &#xA;investigation at 69°N by the joint University of Tromso/University of Saskatchewan MF radar&lt;/a&gt; (Hall et al. 1998) showing that the levels at these latitudes decreasing in summer months.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, long term changes seem to be occurring at high latitudes, with the Hall et al. (2008) observing&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the classical radar turbopause has been at constant altitude at 52°N during the last decade. At 70°N, on the other hand it appears to be moving upward at a rate of between 2 and 7 km decade$^{−1}$.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Although the authors suggest that there may be an anthropogenic cause, the observed reasons for the high latitude change appears to be due to:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the trend we report at 70°N is commensurable with an observed cooling of the mesosphere (and in turn a lowering of the ionospheric E region altitude) and an increasing average electron density in the ionospheric D-region.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="725" LastEditDate="2014-11-28T08:58:43.390" LastActivityDate="2014-11-28T08:58:43.390" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2816" PostTypeId="2" ParentId="2814" CreationDate="2014-11-17T09:23:11.147" Score="8" Body="&lt;p&gt;One of quite elegant physical demonstrations by &lt;a href=&quot;https://en.wikipedia.org/wiki/Robert_W._Wood&quot;&gt;Robert W. Wood&lt;/a&gt; involved re-creating a tornado in a lecture hall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source (quoting from memory):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seabrook, W. Doctor Wood, Modern Wizard of the Laboratory. New York, 1941.&lt;/p&gt;&#xA;" OwnerUserId="269" LastActivityDate="2014-11-17T09:23:11.147" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2817" PostTypeId="2" ParentId="2814" CreationDate="2014-11-17T11:49:58.860" Score="11" Body="&lt;p&gt;Real clouds are beautiful because they are huge and you observe them from far away, thereby gaining the ability to see a distinct &quot;boundary&quot; and, therefore, shape. But if you ever travel through a cloud in a plane, thereby seeing one close up, you'll find that they really are &quot;just fog&quot;. You'd struggle to recreate a scale cloud in a tiny environment; water molecules have a reasonably consistent size and you can't just downscale the entire system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly, you could probably create a thunderstorm but at that scale it would be over so fast you'd barely see it. An obvious example is the movement of water droplets as steam leaves your kettle and condenses. You just see a quick whoosh of vapour particles spiralling about and, well, that's about as close to a rainstorm as you'll get.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some phenomena, such as air vortices, can manifest at smaller scales &amp;mdash; I've seen more than a few mini-tornados forming in my garden dragging leaves around in a funnel fashion &amp;mdash; but I'm not sure you'd ever be able to contain enough energy to see that happen for more than a fraction of a second in a small tube.&lt;/p&gt;&#xA;" OwnerUserId="1136" LastEditorUserId="1136" LastEditDate="2014-11-17T21:04:44.997" LastActivityDate="2014-11-17T21:04:44.997" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2818" PostTypeId="2" ParentId="2814" CreationDate="2014-11-17T16:08:58.420" Score="9" Body="&lt;p&gt;I recall reading on a couple of occasions how a very large NASA hangar exhibited a phenomenon of 'raining indoors.' It was no roof leak, either, because it could be a cloudless night and it would still happen. Supposedly, there were actually clouds forming inside the building.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is an article about it:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.popsci.com/technology/article/2010-03/nasa-and-us-navy-pledge-save-silicon-valleys-massive-airship-hangar&quot;&gt;http://www.popsci.com/technology/article/2010-03/nasa-and-us-navy-pledge-save-silicon-valleys-massive-airship-hangar&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1137" LastActivityDate="2014-11-17T16:08:58.420" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="2819" PostTypeId="2" ParentId="2811" CreationDate="2014-11-17T19:02:32.790" Score="7" Body="&lt;p&gt;There's a little more to it than its substantial age, but not a lot. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, a bit of background. We need a few conditions for accumulations of oil or gas:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A &lt;a href=&quot;https://en.wikipedia.org/wiki/Kerogen&quot;&gt;kerogen&lt;/a&gt;-rich source rock that has been 'cooked' to thermal maturity. Insufficient temperature, or insufficient time, and it's undercooked; if the temperature is too high, or the rock is very old, then the volatiles have all been discharged or cracked. I don't know of any source rocks older than about Ordovician; the best ones are Jurassic in age. &lt;/li&gt;&#xA;&lt;li&gt;A migration pathway from the source to a trapping configuration, and time for this to have happened.&lt;/li&gt;&#xA;&lt;li&gt;A &lt;a href=&quot;https://en.wikipedia.org/wiki/Structural_trap&quot;&gt;structural&lt;/a&gt; or stratigraphic trap, such as an anticline, and the geological conditions that have preserved it since filling. &lt;/li&gt;&#xA;&lt;li&gt;A reservoir rock — a porous and permeable rock. Usually this is a sedimentary rock, though hydrocarbons have been discovered in fractured granites (in Vietnam for example; this is rare).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Only 'conventional' hydrocarbon deposits need all these conditions (sometimes called a &lt;a href=&quot;http://subsurfwiki.org/wiki/Petroleum_system&quot;&gt;'petroleum system'&lt;/a&gt;, such as you might find in the North Sea). 'Shale gas' is basically just a mature source rock — we can extract hydrocarbons from it by fracking, for example. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you might guess from the list of conditions, there are lots of things that can destroy a hydrocarbon accumulation, or preclude its formation. For example, deep burial destroys porosity by diagenesis and compaction. Time increases the likelihood of trap leakage or thermal destruction of volatiles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, why no hydrocarbons in the (mostly Precambrian) Swedish-Norwegian shield? Maybe these are the top 3 reasons:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;These old rocks never had a good source rock: too old, too little life. A bad start.&lt;/li&gt;&#xA;&lt;li&gt;They are so old that any source would have been mature hundreds of millions of years ago.&lt;/li&gt;&#xA;&lt;li&gt;In any case, metamorphosis has destroyed any potential reservoirs, and a combination of tectonism, orogenesis, and exhumation has destroyed any traps. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2014-11-17T19:02:32.790" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2820" PostTypeId="1" CreationDate="2014-11-17T21:41:57.407" Score="9" ViewCount="223" Body="&lt;p&gt;Reading &lt;em&gt;Meteorology Fundamentals&lt;/em&gt; by Sylvie Malardel, it says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We observe a symmetry of the cloudy bands with respect to the rotation axis of Earth &#xA;  and between Northern Hemisphere and Southern Hemisphere.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What is the origin of those symmetries?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/w4dy1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="1138" LastEditorUserId="1138" LastEditDate="2014-11-18T11:42:49.323" LastActivityDate="2015-01-12T23:20:54.713" Title="Where does the symmetry of cloudy bands come from?" Tags="|meteorology|clouds|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2821" PostTypeId="2" ParentId="1008" CreationDate="2014-11-18T02:19:42.907" Score="7" Body="&lt;p&gt;According to the NOAA document &lt;a href=&quot;http://www.spc.noaa.gov/publications/schaefer/sndgparm.pdf&quot; rel=&quot;nofollow&quot;&gt;A Comparison of Rawinsonde Data from the Southeastern United States during El Niño, La Niña, and Neutral Winters&lt;/a&gt; (Sankovich et al.) report that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Schaefer and Tatom (1998) considered&#xA;  the number of tornadoes per year in the United&#xA;  States and sea surface temperatures (SST) in&#xA;  various portions of the Pacific Ocean to try to&#xA;  discern an impact of ENSO on the occurrence of&#xA;  tornadoes. Their statistical inquiries showed no&#xA;  major influence, but their &lt;strong&gt;data does show a signal&#xA;  that more tornadoes tend to occur in the mideastern&#xA;  states during the La Niña phase.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, another study cited by Agee&#xA;and Zurn-Birkhimer (1998) state&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;that tornado&#xA;  occurrences do not favor one ENSO phase but&#xA;  rather exhibit a shift in geographic location. For&#xA;  example, their &lt;strong&gt;results suggest that more&#xA;  tornadoes occur in the lower Midwest, Ohio Valley,&#xA;  Tennessee Valley, and mid-Atlantic region during&#xA;  the La Niña phase than in any other phase.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is further concluded by Bove (1998) concluded that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;increased tornado activity over&#xA;  the Ohio and Tennessee River Valleys during the&#xA;  cold La Niña phase.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Sankovich et al. conclude that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Like all climatological signals, they [ENSO]&#xA;  represent long-term trends. They do not provide a&#xA;  tool for making seasonal or other extended&#xA;  forecasts; rather, they show that other things being&#xA;  equal, the atmospheric stratification over the&#xA;  Southeastern United States is typically less&#xA;  compatible for the occurrence of severe&#xA;  thunderstorms (3/4” or larger hail, thunderstorm&#xA;  gusts of 58 mph or faster, tornados) during a La&#xA;  Niña winter than during Neutral or El Niño winters.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In the paper &lt;a href=&quot;http://iopscience.iop.org/1748-9326/4/2/024012/pdf/1748-9326_4_2_024012.pdf&quot; rel=&quot;nofollow&quot;&gt;A seasonal-scale climatological analysis correlating spring tornadic activity with antecedent&#xA;fall–winter drought in the southeastern United States&lt;/a&gt; (Shepherd et al. 2009), state that to &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;remove the uncertainty&#xA;  associated with the ENSO debate, we consider a new approach&#xA;  by focusing on antecedent drought conditions for a region.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Whereby, they conclude that the relationship between drought and incidences of tornadic and severe thunderstorm behaviour to possess a&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;statistically significant tendency for&#xA;  fall–winter drought conditions to be correlated with below-normal tornado days the following&#xA;  spring in north Georgia (i.e. 93% of the years) and other regions of the Southeast. Non-drought&#xA;  years had nearly twice as many tornado days in the study area as drought years and were also&#xA;  five to six times more likely to have multiple tornado days&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;References:&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Schaefer, J. T., and F. B. Tatom, 1998: &lt;a href=&quot;http://www.spc.noaa.gov/publications/schaefer/el_nino.htm&quot; rel=&quot;nofollow&quot;&gt;The&#xA;relationship between El Niño, La Niña, and&#xA;United States tornadoes&lt;/a&gt;, Preprints, 19th Conf.&#xA;on Severe Local Storms, Minneapolis, MN,&#xA;Amer. Meteor. Soc., 416-419.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Agee, E., and S. Zurn-Birkhimer, 1998: Variations&#xA;in USA tornado occurrences during El Niño&#xA;and La Niña, Preprints, 19th Conf. on Severe&#xA;Local Storms, Minneapolis, MN, Amer.&#xA;Meteor. Soc., 287-290.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Bove, M.C., 1998: Impacts of ENSO on United&#xA;States tornadic activity, Preprints, 19th Conf.&#xA;on Severe Local Storms, Minneapolis, MN,&#xA;Amer. Meteor. Soc., 313-316.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="111" LastEditDate="2014-12-21T21:44:48.903" LastActivityDate="2014-12-21T21:44:48.903" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2822" PostTypeId="1" CreationDate="2014-11-18T03:14:06.573" Score="15" ViewCount="14643" Body="&lt;p&gt;What are the characteristics that distinguishes a El Niño Modoki from a &quot;normal&quot; El Niño? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the effects of El Niño Modoki on atmospheric and oceanic processes? How does it affect weather systems? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the mechanisms that determine whether an El Niño event is a normal event or a Modoki event?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2014-11-18T13:58:58.810" LastActivityDate="2015-04-19T01:48:44.457" Title="What is El Niño Modoki?" Tags="|meteorology|atmosphere|ocean|enso|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2823" PostTypeId="1" AcceptedAnswerId="4343" CreationDate="2014-11-18T03:21:40.717" Score="7" ViewCount="388" Body="&lt;p&gt;Conceptually they seem to be showing the same information. But in the context of a Madden Julien Oscillation (MJO) or equatorial waves  especially over the equatorial oceanic layers which one is more useful to look at:&#xA;1) OLR Map or, &#xA;2) IR Satellite Imagery (black and white satellite pictures of clouds)? &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorUserId="192" LastEditDate="2015-01-29T17:53:00.910" LastActivityDate="2015-01-30T21:38:56.617" Title="What are the advantages in looking at an OLR map versus looking at IR satellite imagery?" Tags="|meteorology|measurements|clouds|remote-sensing|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="2824" PostTypeId="1" AcceptedAnswerId="2828" CreationDate="2014-11-18T03:31:13.510" Score="7" ViewCount="398" Body="&lt;p&gt;I am a geological novice so maybe this is a wrong question. But the idea is to create a thought experiment. How does one &quot;create&quot; petroleum or crude oil for future generations? Is it enough to bury a lot of trees underneath the earth at great depths and eventually thousands (maybe hundreds of thousands years) later crude oil is formed? &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorUserId="100" LastEditDate="2014-11-18T11:40:45.813" LastActivityDate="2014-12-19T06:42:29.233" Title="How does one create petroleum/crude oil for future generations?" Tags="|geology|fossil-fuel|petroleum|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2825" PostTypeId="2" ParentId="2822" CreationDate="2014-11-18T06:48:10.537" Score="7" Body="&lt;p&gt;According to the JAMSTEC webpage &lt;a href=&quot;http://www.jamstec.go.jp/frcgc/research/d1/iod/enmodoki_home_s.html.en&quot; rel=&quot;nofollow noreferrer&quot;&gt;The El Niño Modoki&lt;/a&gt;, the difference between the El Niño Modoki from a &quot;normal&quot; El Niño is a question of where the anomalous sea surface temperatures (SST) are located. It should be noted that there is a reverse phenomena referred to as the La Niña Modoki, where the opposite SST anomalies are reversed - often it is referred to as ENSO Modoki.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the El Niño Modoki, the warmer SSTs are in the central Pacific, rather than in the western Pacific, while the 'normal' El Niño would have a SST signature like below (from JAMSTEC):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/hiXAD.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The El Niño Modoki has a SST signature as below (from JAMSTEC):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/4xfSL.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the JAMSTEC site, the consequences of this phenomenon are&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Such zonal SST gradients result in anomalous two-cell Walker Circulation over the tropical Pacific, with a wet region in the central Pacific.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Which results in less rainfall in China, Japan and the western US.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the article &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-12-00107.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Classifying El Niño Modoki I and II by Different Impacts on Rainfall in Southern China and Typhoon Tracks&lt;/a&gt; (Wang and Wang, 2013), there are in fact two 'modes' of the El Niño Modoki:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Type I occurs with the warm water anomaly in equatorial central Pacific waters, and &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Type II occurs with the anomaly in the subtropical northeastern Pacific&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pertinent to the effects these have are the 'geometries' of the warm SST anomalies that occur with each type.  Specifically, type I being described by the authors as being&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;a symmetric SST anomaly distribution about the equator with the maximum warming in the equatorial central Pacific, &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and is associated with&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;anomalous anticyclone in the Philippine Sea that induces southwesterly wind anomalies along the south coast of China and carries the moisture for increasing rainfall in southern China. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and type II being &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;an asymmetric distribution with the warm SST anomalies extending from&#xA;  the northeastern Pacific to the equatorial central Pacific.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The consequences are that &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;an anomalous cyclone resides east of the Philippines, associated with northerly wind anomalies and a decrease in rainfall in southern China.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Both the 'normal' El Niño and El Niño Modoki type I are associated with a westward extension of the western North Pacific subtropical high (WNPSH), whereas the El Niño Modoki type II pushes the WNPSH eastward.  The type II causes the typhoon steering flow to have a northwesterly anomaly, making it unlikely for typhoons to make landfall in China.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A growing consequence of this, according to JAMSTEC's webpage &lt;a href=&quot;http://www.jamstec.go.jp/frcgc/research/d1/iod/e/elnmodoki/about_elnm.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;El Niño Modoki&lt;/a&gt;, is that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Several studies have shown that the ENSO Modoki has become more prominent in recent times, as compared to ENSO, and thereby changing the teleconnection pattern arising from the tropical Pacific. Moreover, the associated decadal changes in the sea level are shown to affect not only the islands of central Pacific but remote regions off California and southwestern Indian Ocean&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It has also have been found to affect stratospheric ozone in the recent article &lt;a href=&quot;http://iopscience.iop.org/1748-9326/9/6/064020/pdf/1748-9326_9_6_064020.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;The relative impacts of El Niño Modoki,&#xA;canonical El Niño, and QBO on tropical&#xA;ozone changes since the 1980s&lt;/a&gt; (Xie et al. 2014), with&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In the light of an analysis of the observations and&#xA;  simulations, we found that Modoki, as a new driver of global climate change, can modulate the&#xA;  tropical upwelling that significantly affects mid-lower stratospheric ozone. As a result, it has&#xA;  an important impact on the variations of tropical total column ozone (TCO), alongside quasibiennial&#xA;  oscillation or canonical ENSO. Our results suggest that, in the context of future global&#xA;  warming, Modoki activity may continue to be a primary driver of tropical TCO changes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-11-18T06:55:26.053" LastActivityDate="2014-11-18T06:55:26.053" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2826" PostTypeId="2" ParentId="2822" CreationDate="2014-11-18T06:52:44.707" Score="11" Body="&lt;p&gt;Here is a nice picture from &lt;a href=&quot;http://www.nature.com/nature/journal/v461/n7263/fig_tab/461481a_F2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ashok &amp;amp; Yamagata (2009)&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems like the Kelvin wave is held back for some reason that I am not familiar with. From the figure below it looks analogous to a standing wave vs a freely propagating wave.  Interestingly, some authors argue that the frequency of these events has increased in recent years for anthropogenic reasons. i.e. climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/7IeD2.jpg&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;a&lt;/strong&gt;, An El Niño event is produced when the easterly winds weaken; sometimes, in the west, westerlies prevail. This condition is&#xA;  categorized by warmer than normal sea surface temperatures (SSTs) in&#xA;  the east of the ocean, and is associated with alterations in the&#xA;  thermocline and in the atmospheric circulation that make the east&#xA;  wetter and the west drier. &lt;strong&gt;b&lt;/strong&gt;, An El Niño Modoki event is an&#xA;  anomalous condition of a distinctly different kind. The warmest SSTs&#xA;  occur in the central Pacific, flanked by colder waters to the east and&#xA;  west, and are associated with distinct patterns of atmospheric&#xA;  convection. &lt;strong&gt;c&lt;/strong&gt;, &lt;strong&gt;d&lt;/strong&gt;, The opposite (La Niña) phases of the El Niño&#xA;  and El Niño Modoki respectively. Yeh et al.3 argue that the increasing&#xA;  frequency of the Modoki condition is due to anthropogenic warming, and&#xA;  that these events in the central Pacific will occur more frequently if&#xA;  global warming increases.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The most concise definition i found is:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The peak warming of the sea surface temperature anomaly (SSTA) is confined to the  central equatorial Pacific until boreal winter instead of propagating to the east.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You may already be familiar with this paper, but I found this passage interesting:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Because of the obvious distinction from the traditional El Niño&#xA;  [Rasmusson and Carpenter, 1982] and even from that defined by NOAA in&#xA;  2003, we refer to the SSTA pattern observed in 2004, namely, warming&#xA;  in the central Pacific (∼NINO4 region) flanked by colder SSTA to the&#xA;  west and east, as an El Niño Modoki (pseudo-El Niño) event; this term&#xA;  is now popular in Japan and east Asia. (The word Modoki was introduced&#xA;  by T. Yamagata during 2004 while explaining a probable cause behind&#xA;  the abnormal summer climatic conditions over Japan. It has been often&#xA;  used since then by various Japanese Mass Media. “Modoki” is a&#xA;  classical Japanese word which means “similar but different.” A news&#xA;  article also appeared in The Japan Times on 24 July 2004 under the&#xA;  heading “'Mock El Niño' culprit behind heat wave, floods: Professor,”&#xA;  which follows: “The heat wave and floods in various parts of Japan are&#xA;  being caused by an El Niño-like phenomenon in the central Pacific&#xA;  Ocean, a Japanese researcher said Friday. Toshio Yamagata, a professor&#xA;  at the University of Tokyo specializing in climate dynamics, said an&#xA;  increase in the sea surface temperature has activated convection&#xA;  currents and promoted a high-pressure ridge in the Pacific, bringing a&#xA;  hot summer to Japan …”&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2006JC003798/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ashok et al. 2007&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="111" LastEditDate="2014-12-21T21:42:40.133" LastActivityDate="2014-12-21T21:42:40.133" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2827" PostTypeId="1" AcceptedAnswerId="2829" CreationDate="2014-11-18T10:55:32.713" Score="25" ViewCount="10479" Body="&lt;p&gt;Is there some kind of math rule for how much does a mountain extend (depth) below the surface?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found an article like this &lt;a href=&quot;http://www.livescience.com/6595-depth-himalayan-mountain-roots-revealed.html&quot;&gt;http://www.livescience.com/6595-depth-himalayan-mountain-roots-revealed.html&lt;/a&gt; says that subduction is rare, does this mean mountains don't usually extend below surface?&lt;/p&gt;&#xA;" OwnerUserId="1146" LastEditorUserId="1146" LastEditDate="2014-11-18T11:36:29.703" LastActivityDate="2014-11-27T09:17:21.730" Title="How much of a mountain is below the surface?" Tags="|geology|mountains|structural-geology|isostasy|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2828" PostTypeId="2" ParentId="2824" CreationDate="2014-11-18T11:33:31.150" Score="8" Body="&lt;p&gt;Geological processes are just too slow. Although, given how quickly we are pumping greenhouse gases into the atmosphere, humanity may well (in a generation or two) be growing biological material as fast as possible and throwing it into deep holes in the ground, which will give another fossil-fuel resource in a few million years. But we'll be doing that just to sequester carbon dioxide from out of the atmosphere, not to invest in future hydrocarbon supplies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hydrocarbons are useful because they have very high energy density: the energy stored per unit weight and unit volume is extremely high. Furthermore, that energy can be harnessed with very primitive technology - just burn it. Because we've been relying on them for nearly two centuries now, we've got very good at safely transporting them globally, and safely storing them in a form ready for immediate use.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, hydrocarbons have two uses: one, they act as storage, as a time-buffer for time-sensitive energy demands such as electricity consumption. And two, their energy density makes them very suitable for powering transport on irregular or changeable routes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, as a means of energy storage, they're not very efficient: even the best CCGT gas-powered electricity generators are only 60% efficient; and internal combustion engines tend to give an efficiency of about 20-25%, tank-to-wheel. And that's without the losses involved in creating the hydrocarbons in the first place&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So whether hydrocarbons have a future as a source of energy is very dubious, because for almost all applications, we now have superior options.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And the future for fossil hydrocarbons must, for the sake of human civilisation, be short and quickly-tapering, because of the risk of catastrophic global warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For some transport applications, the energy density is still a winning attribute of hydrocarbons: most notably, powered flight for freight and travel.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We already have two routes to non-fossil hydrocarbons: biological sources, and direct chemical synthesis. Each involves capturing atmospheric CO&lt;sub&gt;2&lt;/sub&gt;, and combining with water, to generate a blend of hydrocarbons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, we already have means of creating &lt;a href=&quot;http://www.atag.org/our-activities/sustainable-aviation-biofuels.html&quot; rel=&quot;nofollow&quot;&gt;hydrocarbons suitable for flight&lt;/a&gt; (e.g. Jet-A and Jet-A1 fuels). And there are already demonstration plants that have closed-loop generation of synthetic hydrocarbons, for use in electricity-grid-balancing, by using surplus electricity to synthesise methane, which is then burnt in gas turbines when required. Similarly, &lt;a href=&quot;http://www.telegraph.co.uk/earth/energy/fuel/9619269/British-engineers-produce-amazing-petrol-from-air-technology.html&quot; rel=&quot;nofollow&quot;&gt;Tony Marmont's team have been synthesising petrol (gasoline) from air, water, and electricity&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, none of those things mean that hydrocarbons necessarily have much of a future, beyond plastics production. Because hydrocarbon-powered aviation has a lot of environmental problems beyond just CO&lt;sub&gt;2&lt;/sub&gt; emissions, in particular it makes other contributions to exacerbating global warming. And there are lots of options for energy storage within the electricity supply chain.&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="725" LastEditDate="2014-12-19T06:42:29.233" LastActivityDate="2014-12-19T06:42:29.233" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2829" PostTypeId="2" ParentId="2827" CreationDate="2014-11-18T11:40:26.533" Score="23" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is there some kind of math rule for how much does a mountain extends (depth) below the surface?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Definitely! It is called &lt;strong&gt;isostasy&lt;/strong&gt;. When I was a student, the lecture about isostasy started with a slide asking &quot;why don't the mountains fall over?&quot; (it may sound better in my native language..)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, some background:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mountains, and in general the Earth's crust is part of the &lt;strong&gt;lithosphere&lt;/strong&gt;. This lithosphere is the outermost layer of the Earth from a mechanical point of view. It is a relatively non-dense, solid and rigid piece of rock. The lithosphere lies on top of the &lt;strong&gt;asthenosphere&lt;/strong&gt;, which is a more ductile layer composed of the upper mantle. In a sense, the lithosphere &quot;floats&quot; in the asthenosphere. You can think of ice cubes floating on water, or a better comparison would be solid cold chocolate floating on warm (but still solid) chocolate. There are two isostasy models: the Airy model and the Pratt model. The Airy model deals only with topography variations, so this is what I will consider here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's take the following example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/3MW8y.gif&quot; alt=&quot;isostasy&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;(source: &lt;a href=&quot;http://www.globalchange.umich.edu/globalchange1/current/lectures/topography/topography.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.globalchange.umich.edu/globalchange1/current/lectures/topography/topography.html&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The two different settings, ocean and mountain, would be in equilibrium if the pressure at the bottom is equal: $$ P_1 = P_2 $$ Translating pressures to depth and density: $$\rho_1 g h_1 = \rho_2 g h_2 $$. You can either solve for the above example (hint: it is not exactly in equilibrium), or you can use this relationship to derive expressions for how much root would a mountain need in order to &quot;not fall over&quot;. The Wikipedia &lt;a href=&quot;http://en.wikipedia.org/wiki/Isostasy&quot; rel=&quot;nofollow noreferrer&quot;&gt;article on isostasy&lt;/a&gt; has an excellent illustrated example that you can follow and understand. It also describes the Pratt model that I did not touch in this explanation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can also see a nice simulation of isostasy in the source link given below the drawing, where you can play with various settings and see how the cube (&lt;em&gt;i.e.&lt;/em&gt; crust) responds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What happens in the Himalaya?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I found an article like this&#xA;  &lt;a href=&quot;http://www.livescience.com/6595-depth-himalayan-mountain-roots-revealed.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.livescience.com/6595-depth-himalayan-mountain-roots-revealed.html&lt;/a&gt;&#xA;  that says that subduction is rare, does that mean that mountains don't&#xA;  usually extend below surface?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not exactly. Mountains extend below the surface in any case. Subduction is also something that is very common. For example, the Pacific plate subducts under South America, precisely because it is oceanic crust denser than the continental crust of the Andes mountain range.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The article does not state that subduction is rare, it states that deep subduction of continental crust under continental crust is rare. This makes sense - in contrast to the Pacific and Andes example, here you have the continental crust of India colliding with the continental crust of Asia. Both are not dense and one is not supposed to subduct under the other. What you expect to see is that they both fold together. The article you linked to talks about a discovery in which the Indian plate is subducting below the Asian plate. This is not something you can easily describe with the Airy isostasy model since there are more forces involved - horizontal and not only vertical. Actually, this is why they need the computer simulations to figure it out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This question might also be of interest:&#xA;&lt;a href=&quot;https://earthscience.stackexchange.com/q/563/725&quot;&gt;What is the current theory about the formation of Tibet?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also related is this article:&#xA;&lt;a href=&quot;http://arstechnica.com/science/2014/11/researchers-rule-out-a-tectonic-aneurysm-in-the-himalayas/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Researchers rule out a “tectonic aneurysm” in the Himalayas&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-11-27T09:17:21.730" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2830" PostTypeId="1" AcceptedAnswerId="2831" CreationDate="2014-11-18T12:04:32.333" Score="36" ViewCount="18188" Body="&lt;p&gt;Reading a course on Precambrian, I read that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Earth Age (around 4.5 billion years) is dated thanks to the meteorites hitting Earth during its formation rather than the inner materials composing the Earth.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Wouldn't it be more accurate by doing it with its inner materials? Why do we use meteorites if they hit the Earth after its formation?&lt;/p&gt;&#xA;" OwnerUserId="1138" LastEditorDisplayName="user12525" LastEditDate="2019-04-16T09:23:25.933" LastActivityDate="2022-05-03T03:58:00.590" Title="Why is Earth's age given by dating meteorites rather than its own rocks?" Tags="|geology|geochemistry|earth-history|meteorite|precambrian|" AnswerCount="4" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2831" PostTypeId="2" ParentId="2830" CreationDate="2014-11-18T12:17:09.193" Score="39" Body="&lt;p&gt;&lt;strong&gt;Some background:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We are able to determine the age of certain rocks and minerals using measurements of radioactive and radiogenic isotopes of certain elements. The most common are U-Th-Pb, Rb-Sr and Sm-Nd. Simply put, the resulting date is the time that has passed from the crystallisation of that mineral. Obviously there are complexities, but there are not critical for this answer.&#xA;&lt;br&gt;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Why do we use meteorites if they hit the Earth after its formation?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Short answer&lt;/strong&gt;: because the meteorites formed together with the Earth and the rest of the Solar System.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Long answer&lt;/strong&gt;: The Earth formed together with the rest of the Solar System and its meteorites around 4.5 billion years ago. When meteorites fall on Earth and you pick them up, you are able to date the time of their formation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You say:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Why do we use meteorites if they hit the Earth after its formation?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You have to distinguish the time that the meteorites form and the time that they hit the Earth. If I throw a meteorite at you, and you date it, it still records the formation time and not the time that I threw it at you. Hitting the Earth does not reset the radioactive clock in the meteorite's minerals.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Wouldn't it be more accurate by doing it with its inner materials?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It would. There are two problems:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;We don't have materials from the time of Earth's formation. The Earth is a dynamic place, and rocks are getting formed and destroyed all the time (also see &lt;a href=&quot;https://earthscience.stackexchange.com/q/773/725&quot;&gt;related question&lt;/a&gt;). It may be that such old rocks exist on Earth, but because they are so old there are either metamorphosed and buried deep in the Earth or covered by sedimentary rocks. The oldest exposed rock on Earth available for study is the 4 billion year Acasta Gneiss in Canada. The oldest mineral on Earth is a zircon found in Australia, which is 4.4 billion years old. These are the only two materials that are known to be older than 4 billion years on Earth. There could be more, but we just couldn't find them.&lt;/li&gt;&#xA;&lt;li&gt;The moon forming event occurred some tens of million of years after the formation of the Earth. This event destroyed the Earth's crust and any evidence of the age of the Earth, on Earth itself.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;This is why meteorites are excellent for this task - they mostly formed during the formation of the Solar System.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-11-19T12:46:56.330" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="2832" PostTypeId="1" AcceptedAnswerId="2929" CreationDate="2014-11-18T13:15:47.847" Score="13" ViewCount="1324" Body="&lt;p&gt;Dropstones sometimes occur in sedimentary rocks. These are foreign rocks and boulders that happened to &amp;quot;drop&amp;quot; into a sediment and were fossilised when the sediment was lithified.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/JCvHd.jpg&quot; alt=&quot;Dropstone&quot; /&gt;&#xA;&lt;sup&gt;(&lt;a href=&quot;https://en.wikipedia.org/wiki/File:IRD_mcr1.JPG&quot; rel=&quot;nofollow noreferrer&quot;&gt;source: Michael C. Rygel via Wikimedia Commons&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;But what about meteorites? You can find meteorites here on Earth, and while such large blocks as pictured may be extremely rare, they do exist somewhere. We don't have a lot of meteorites now, but it seems to me that if we go back billions of years, it makes sense that somewhere, sometime, a meteorite has been incorporated into the rock record.&lt;/p&gt;&#xA;&lt;p&gt;I suppose that it is also unlikely because most meteorites fall in the ocean is then subducted and the meteorite &amp;quot;dropstones&amp;quot; are lost to the mantle.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;EDIT&lt;/p&gt;&#xA;&lt;p&gt;I found this recent (2020) paper talking about 20 cm large meteorites in Ordovician sediments, that came from the breakup of a larger asteroid:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1016/j.epsl.2020.116442&quot; rel=&quot;nofollow noreferrer&quot;&gt;Absolute dating of the L-chondrite parent body breakup with high-precision U–Pb zircon geochronology from Ordovician limestone&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2020-08-04T11:21:46.510" LastActivityDate="2020-08-04T11:21:46.510" Title="Have meteorites been found in the oldest sedimentary rocks?" Tags="|earth-history|sedimentology|meteorite|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="2833" PostTypeId="2" ParentId="2832" CreationDate="2014-11-18T15:37:01.053" Score="4" Body="&lt;p&gt;Yes, meteorites have been found in limestone.  See e.g. the following references:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0012821X96002051&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geochemistry of meteorite-rich marine limestone strata and fossil meteorites from the lower Ordovician at Kinnekulle, Sweden&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Thirteen fossil meteorites (⊘ = 1.5–9 cm) have been found in lower Ordovician Orthoceratite Limestone at Kinnekulle, Sweden. The meteorites were recovered from a 3.5 m thick quarried interval in the middle of a 30 m thick section of Orthoceratite Limestone.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.psrd.hawaii.edu/Mar04/fossilMeteorites.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tiny Traces of a Big Asteroid Breakup&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Ancient geologic conditions in southern Sweden were ideal to preserve meteorites that fell to Earth about half a billion years ago. Researcher Birger Schmitz (working as a visiting professor at Rice University and now at the University of Lund, Sweden) and his colleagues in Göteborg, Sweden have analyzed over 40 of these rare fossil meteorites along with relict chromite grains collected from sites in a 250,000-square-kilometer area of 480-million-year-old limestone.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://link.springer.com/article/10.1134%2FS0016702912080022#page-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Origin of fossil meteorites from Ordovician limestone in Sweden&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Mid-Ordovician  (&#xA;  ~470&#xA;    Ma)  limestone  exposed  in&#xA;  the Thorsberg quarry in southern Sweden was found out&#xA;  to contain anomalously high concentrations of meteorites: more than 80 fragments ranging from &#xA;  ~1&#xA;   to 20 cm&#xA;  across were found over an area of 6000 m2&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="248" LastEditorUserId="595" LastEditDate="2018-08-09T08:50:58.287" LastActivityDate="2018-08-09T08:50:58.287" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="2834" PostTypeId="2" ParentId="2830" CreationDate="2014-11-18T18:28:47.417" Score="6" Body="&lt;p&gt;Simple enough, see the meteorites formed alongside the planet, however, since the planet was pretty much a molten soup you can't date it properly, because we can only date it after it cooled down. Meaning that the meteorites hold a much more accurate time-frame since they were not melted down to form our crust! which means their dates (I am using the term loosely) are correct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words meteorites formed with Earth but just decided to chill out there and not be totally melted down for spare parts. While most of our nice rocks formed quite a bit after the planet came to be since they are the cooled down soup that forms our dear crust. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Wouldn't it be more accurate by doing it with its inner materials?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Do you want to go swimming for Uranium? No really, its pretty hard to obtain old, OLD rocks and minerals. Best bet is to analyze meteorites.&lt;/p&gt;&#xA;" OwnerUserId="1154" LastActivityDate="2014-11-18T18:28:47.417" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2835" PostTypeId="2" ParentId="2824" CreationDate="2014-11-18T18:34:17.447" Score="-1" Body="&lt;p&gt;Short answer: Yes, kinda.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Long answer: the processes that govern the creation of oil as you are calling it take a couple hundred million years to happen. So in a human timeframe there is way to 'create' more oil, but if you got a time machine and you bury a couple hundred thousand bodies in a place you will find oil in say 100 million years! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However we can create biofuel from other sources like algea, or corn. As for plastics, they can also be synthetically produced. (by this i mean no oil required.)&lt;/p&gt;&#xA;" OwnerUserId="1154" LastActivityDate="2014-11-18T18:34:17.447" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2836" PostTypeId="2" ParentId="2824" CreationDate="2014-11-18T19:31:54.283" Score="6" Body="&lt;p&gt;This isn't really a complete answer, more of a footnote to @EnergyNumbers answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Aside: I'm not sure what the definition of a 'geological process' is, but it's not quite fair to say they are 'too slow'. Leaving aside a philosophical point about scale invariance, it's easy to think of fast geological processes. So maybe we can't reject the hypothesis on the basis of time alone.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lots of (especially shallow) gas is biogeneic in origin, as opposed to thermogenic. Indeed, Rice (1993) estimated that biogenic gas accounts for about 20% of natural gas resources. Depending on the organic content of the sediment and on the electrochemical environment, methane begins to be produced by various micro-organisms as soon as burial commences, especially in low-oxygen environments. There is tons of literature on this, look for 'organic matter diagenesis' and people like Charles Curtis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's the reaction:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\ce{2CH2O + H2O -&amp;gt; H+ + HCO3^- + CH4}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, organic matter plus water (and bugs) results in bicarbonate (which may end up as a carbonate cement) and methane. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is this not a real answer? Because 'methane' is not 'petroleum' and certainly not 'crude oil'. Biogenic gas tends to be 'dry' (mostly methane), which makes it rather less valuable (i.e. energy-dense) than thermogenic gas. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rice, D. D., 1993, Biogenic gas: controls, habitats, and resource potential, in D. G. Howell, ed., The Future of Energy Gases - U.S. Geological Survey Professional Paper 1570, Washington, United States Government Printing Office, p. 583-606.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="87" LastEditDate="2014-12-03T07:34:04.493" LastActivityDate="2014-12-03T07:34:04.493" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2839" PostTypeId="2" ParentId="2830" CreationDate="2014-11-18T20:55:12.913" Score="19" Body="&lt;p&gt;The answers that have been provided are correct but they're omitting the fundamental issue that explains &lt;strong&gt;why&lt;/strong&gt; they are correct:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you date a rock you get the point that it solidified, not the point the material came into being.  Most rocks on Earth have melted time and again and thus are useless for figuring out how old the Earth is.&lt;/p&gt;&#xA;" OwnerUserId="1160" LastActivityDate="2014-11-18T20:55:12.913" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2840" PostTypeId="1" AcceptedAnswerId="2842" CreationDate="2014-11-18T21:57:47.120" Score="7" ViewCount="967" Body="&lt;p&gt;Still reading a course on datation over multiple stratums that may have setting up the Earth's crust, I'm meeting for the first time the principle of original horizontality Steno.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this theory safe? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Logically, if multiple stratums squeeze, the last one to squeeze will be the youngest. It makes sense to me. But isn't Earth's crust affected by inner perturbations that may disrupt the stratums pile? Is it safe to date stratums this way then?&lt;/p&gt;&#xA;" OwnerUserId="1138" LastEditorUserId="87" LastEditDate="2014-11-19T15:01:23.493" LastActivityDate="2014-11-19T15:01:23.493" Title="Is the Principle of Original Horizontality a good indicator?" Tags="|stratigraphy|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2842" PostTypeId="2" ParentId="2840" CreationDate="2014-11-19T02:02:22.893" Score="8" Body="&lt;p&gt;No, Steno's &lt;a href=&quot;http://en.wikipedia.org/wiki/Principle_of_original_horizontality&quot; rel=&quot;nofollow noreferrer&quot;&gt;principle of original horizontality&lt;/a&gt; (I'll call it the POOH) is not 'safe'. It is not a useful theory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Don't confuse it with the &lt;a href=&quot;http://en.wikipedia.org/wiki/Law_of_superposition&quot; rel=&quot;nofollow noreferrer&quot;&gt;law of superposition&lt;/a&gt; (also due to Steno), which is useful. That law is, in a general sense, a foundation stone (ha!) of stratigraphy... with some caveats due to resedimentation and other processes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is the POOH dodgy? On small and large scales, the concept of 'layer-cake' stratigraphy does not hold up. Indeed, it's probably rather unhelpful. &lt;a href=&quot;https://twitter.com/clasticdetritus&quot; rel=&quot;nofollow noreferrer&quot;&gt;Brian Romans&lt;/a&gt; wrote a nice essay on this subject in &lt;em&gt;52 Things... Geology&lt;/em&gt; (edited by me, 2014) — see the link below. In it, he refers to Bailey (1998), who described sedimentary bodies as 'lenticles' with complex 3D geometries. And you just have to look at some seismic reflection data from the continental shelf to appreciate that this principle applies to even an outwardly rather continuous environment (excerpt of a line in the &lt;a href=&quot;http://www.seismicatlas.org/entity?id=ba4bfcdc-5596-45a2-a320-88622c9f49b3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Virtual Seismic Atlas&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/zV5dD.png&quot; alt=&quot;Seismic section from CGGVeritas, shared by Julien Moreau on VSA&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bailey, R (1998). Review: Stratigraphy, Meta-Stratigraphy, and Chaos. &lt;em&gt;Terra Nova&lt;/em&gt; &lt;strong&gt;10&lt;/strong&gt;, 222-230. DOI: 10.1046/j.1365- 3121.1998.00192.x&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Romans, B (2014). Strata are not flat. In: M Hall, ed., &lt;em&gt;52 Things You Should Know About Geology&lt;/em&gt;. Agile Libre, Nova Scotia, 132 pp. ISBN 978-0-9879594-2-3. &lt;a href=&quot;https://dl.dropboxusercontent.com/u/14965965/Romans_Strata-are-not-flat.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Available online.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2014-11-19T12:39:38.873" LastActivityDate="2014-11-19T12:39:38.873" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2843" PostTypeId="1" AcceptedAnswerId="2852" CreationDate="2014-11-19T06:57:48.880" Score="17" ViewCount="2460" Body="&lt;p&gt;As the core and mantle of the earth cools, it will reach a point where new crust cannot be produced.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can this point be calculated?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we can, has anyone done such calculations?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;" OwnerUserId="1061" LastEditorUserId="1061" LastEditDate="2014-12-17T08:03:44.050" LastActivityDate="2016-10-17T08:50:04.983" Title="At what point does plate tectonics stop?" Tags="|geophysics|plate-tectonics|core|mantle|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2844" PostTypeId="1" CreationDate="2014-11-19T07:48:42.613" Score="10" ViewCount="302" Body="&lt;p&gt;According to the Science Daily article &lt;a href=&quot;http://www.sciencedaily.com/releases/2008/01/080103144448.htm&quot;&gt;Plate Tectonics May Grind To A Halt, Then Start Again&lt;/a&gt; (Carnegie Institution), one main aspect of the research being presented is the hypothesis that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;suggests that plate tectonics may have ground to a halt at least once in our planet's history -- and may do so again&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Specifically, the article states that geochemical evidence of igneous rocks from about a billion years ago suggests there was a lull in subduction processes, coinciding with evidence of the closing of a Pacific-like basin, forming the &lt;a href=&quot;http://en.wikipedia.org/wiki/Rodinia&quot;&gt;supercontinent Rodinia&lt;/a&gt;.  The lulls also, according to the article's authors, in part explain that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;By periodically clamping the lid on heat flow, intermittent plate tectonics may explain why the Earth has lost heat slower than current models predict. And the buildup of heat beneath stagnant plates may explain the occurrence of certain igneous rocks in the middle of continents away from their normal locations in subduction zones.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, the article rather vaguely states that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Rodinia eventually split apart &lt;strong&gt;when subduction and plate tectonics resumed.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What geological mechanism would cause a 'restart' of plate tectonics, specifically subduction?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-11-19T08:37:11.117" LastActivityDate="2015-02-13T16:49:25.637" Title="What geological processes would 'restart' subduction processes?" Tags="|plate-tectonics|subduction|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2845" PostTypeId="1" CreationDate="2014-11-19T07:56:10.883" Score="10" ViewCount="617" Body="&lt;p&gt;There is an oil field outside my hometown. I wonder if it is feasible to use the same oil wells for geothermal production after oil production rate drops below profitable point.&lt;/p&gt;&#xA;" OwnerUserId="1168" LastEditorUserId="725" LastEditorDisplayName="user889" LastEditDate="2016-01-22T00:56:33.890" LastActivityDate="2017-12-08T18:40:19.387" Title="Is it feasible to use depleted oil wells for geothermal production?" Tags="|geothermal-heat|petroleum|drilling|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2846" PostTypeId="2" ParentId="2509" CreationDate="2014-11-19T11:02:51.617" Score="4" Body="&lt;p&gt;The Science Daily article &lt;a href=&quot;http://www.sciencedaily.com/releases/2012/01/120123094523.htm&quot; rel=&quot;nofollow&quot;&gt;How diamond-bearing kimberlites reach the surface of Earth: Acidification provides the thrust&lt;/a&gt; (Ludwig-Maximilians-Universitaet Muenchen (LMU)) reports of research completed by an international research team led by Professor Donald Dingwell, Director of the Department of Geo- and Environmental Sciences at LMU.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They state that ancient cratonic crust provides silicate minerals that result in the originally basic magma to become more buoyant and as they are forced through the pipes, it causes the buoyant magma to move fast.  With the authors describing that as the magma ascent increases in velocity, the more silicates it gathers (entrains), increasing the dissolved silicate concentration - until the amount of released $\mathrm{CO}_2$ and $\mathrm{H_2O}$ greatly increasing the velocity of ascent, as the authors state 'like a rocket'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A more thorough geochemical description is provided in the article &lt;a href=&quot;http://www.nature.com/nature/journal/v481/n7381/full/nature10740.html&quot; rel=&quot;nofollow&quot;&gt;Kimberlite ascent by assimilation-fuelled buoyancy&lt;/a&gt; (Russell et al. 2012), the proposed model mechanism as the original kimberlite melt to be &lt;a href=&quot;http://www.geology.sdsu.edu/how_volcanoes_work/Unusual%20lava.html&quot; rel=&quot;nofollow&quot;&gt;carbonatite&lt;/a&gt;-like - poor in silica content, this magma assimilates materials during its accent through the upper mantle and crust, becoming more silicic, causing the $\mathrm{CO}_2$ solubility to decrease, reducing density and increasing buoyancy, causing the magma to accelerate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of why cratonic crust is the locale of many diamond rich kimberlite pipes is described from Professor Dingwell as being due to the silica rich cratonic crust is thick enough to provide the magma to make contact with the silicate rich minerals therein.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="725" LastEditDate="2014-11-29T11:17:22.493" LastActivityDate="2014-11-29T11:17:22.493" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2847" PostTypeId="2" ParentId="2804" CreationDate="2014-11-19T12:58:40.037" Score="6" Body="&lt;p&gt;Schneider von Deimling et al. in &lt;a href=&quot;http://www.biogeosciences.net/9/649/2012/bg-9-649-2012.pdf&quot; rel=&quot;nofollow&quot;&gt;Estimating the near-surface permafrost-carbon feedback on global warming&lt;/a&gt; Biogeosciences, 9, 649–665, 2012 evaluated carbon dioxide and methane release under four senarios, the worst being RPC8.5.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Under RPC8.5, they calculated release of carbon from permafrost through 2100 of 63 gigatons (Gt) as CO&lt;sub&gt;2&lt;/sub&gt; and 0.5Gt as methane.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Through 2200 (cumulatively): 302Gt as CO&lt;sub&gt;2&lt;/sub&gt; and 5Gt as methane.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Through 2300: 380Gt as CO&lt;sub&gt;2&lt;/sub&gt; and 12Gt as methane.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other estimates and nice figures are in the UN Environmental Program report &lt;a href=&quot;http://www.unep.org/pdf/permafrost.pdf&quot; rel=&quot;nofollow&quot;&gt;Policy Implications of Warming Permafrost&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="725" LastEditDate="2014-12-18T07:14:13.200" LastActivityDate="2014-12-18T07:14:13.200" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2848" PostTypeId="2" ParentId="2845" CreationDate="2014-11-19T14:19:06.557" Score="8" Body="&lt;p&gt;In most cases, probably not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oil could be considered a metamorphic mineral, formed by &quot;gentle&quot; heating. That is gently on a geological scale - still enough to burn your hands!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geothermal systems work most efficiently with a large temperature difference (Third Law of Thermodynamics). As soon as the temperatures increase enough to be interesting from a geothermal perspective, you are quickly losing (&quot;overcooking&quot;) the oil on a geological timescale. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore most oil fields have had the heat applied in the past and it has since been removed. &#xA;However this does not discount the situation where an oil field is still technically &quot;being made&quot; and the hydrocarbons are still being heated, and we just happened to drill it at just the right time. Hence the &quot;in most cases&quot;: You might find the odd field where it is practical.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An old field, especially gas ones, could be used for carbon sequestration though. The field has stored methane for 10s if not 100s million years, why not the heavier CO&lt;sub&gt;2&lt;/sub&gt; instead?&lt;/p&gt;&#xA;" OwnerUserId="44" LastEditorUserId="725" LastEditDate="2014-12-19T06:46:29.823" LastActivityDate="2014-12-19T06:46:29.823" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2849" PostTypeId="2" ParentId="571" CreationDate="2014-11-19T14:23:11.873" Score="10" Body="&lt;p&gt;According to this University of Wisconsin reference &lt;a href=&quot;http://whyfiles.org/100oil/2a.html&quot;&gt;http://whyfiles.org/100oil/2a.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;12.5% of oil and gas is from organisms that lived 5 to 34 million years ago.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if we take an estimate for the total oil in place before human extraction of 4 trillion barrels, this would be 500 billon barrels.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So a crude estimate might be 500 billion barrels per 30 million years or 17,000 barrels per year.  &lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2014-11-19T14:23:11.873" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2850" PostTypeId="1" AcceptedAnswerId="2851" CreationDate="2014-11-19T18:26:02.497" Score="13" ViewCount="1974" Body="&lt;p&gt;We know that plates can subduct, causing one plate to be pushed into the core by another.  As the plates move, the subduction continues, pushing one plate under the other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this process continues, logic says, the entire plate could be subducted under the other. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has this ever happened?  How would we know?&lt;/p&gt;&#xA;" OwnerUserId="330" LastEditorUserId="124" LastEditDate="2014-11-19T22:28:20.020" LastActivityDate="2014-11-20T10:50:51.900" Title="Has an entire plate ever subducted?" Tags="|geophysics|plate-tectonics|subduction|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2851" PostTypeId="2" ParentId="2850" CreationDate="2014-11-19T18:26:02.497" Score="8" Body="&lt;p&gt;Excellent question!  Indeed, entire plates have subducted before.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One example is the Intermontane Plate (&lt;a href=&quot;https://en.wikipedia.org/wiki/Intermontane_Plate&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;).  This plate sat west of North America around 195 million years ago.  The plate contained a chain of volcanic islands on its western edge (known as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Intermontane_Islands&quot; rel=&quot;noreferrer&quot;&gt;Intermontane Islands&lt;/a&gt;).  As the plate subducted under the North American plate, that island chain stood too tall and merged with the North American plate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An illustration of the plate:&lt;br/&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/m3oXq.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;br/&gt;&#xA;&lt;sub&gt;Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Intermontane_arc.png&quot; rel=&quot;noreferrer&quot;&gt;Black Tusk, Wikimedia Commons&lt;/a&gt; &lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The entire Intermontane Plate was subducted under the North American plate.  However, we are able to see the remnants of the plate in the volcanic islands it left behind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once this Intermontane Plate was subducted, the Insular Plate became the new subduction zone.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This entire process was actually repeated with the Insular Plate, subducting the entire plate, leaving behind yet another chain of volcanic islands that fused to the western coast of the North American Plate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Burke Museum has an excellent article that describes the subduction of both the &lt;a href=&quot;http://www.burkemuseum.org/static/geo_history_wa/The%20Omineca%20Episode.htm&quot; rel=&quot;noreferrer&quot;&gt;Intermontane Plate&lt;/a&gt; and the &lt;a href=&quot;http://www.burkemuseum.org/static/geo_history_wa/Coast%20Range%20Episode.htm&quot; rel=&quot;noreferrer&quot;&gt;Insular Plate&lt;/a&gt;.  Well worth the read.&lt;/p&gt;&#xA;" OwnerUserId="330" LastActivityDate="2014-11-19T18:26:02.497" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2852" PostTypeId="2" ParentId="2843" CreationDate="2014-11-19T19:22:53.143" Score="14" Body="&lt;p&gt;One permanent threat to plate tectonics is the oceans vanishing. The scientific jury may still be out on this matter, but most geologists and geophysicists consider water to be the lubricant that makes plate tectonics possible. In a billion years or so, the Sun will have become 10% more luminous. This is conjectured to make the Earth to undergo an unstoppable moist greenhouse / runaway greenhouse, and the oceans will vanish.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The core is still emitting residual heat from the formation of the Earth. As the core cools, iron in the outer core freezes onto the inner core. This is freezing is an additional source of heat. The solidification of the Earth's core thus represents another permanent threat to plate tectonics. The liquid outer core is conjectured to have frozen solid less than three billion years from now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A nearer term threat is the formation of the next supercontinent. Plate tectonics may operate in fits and starts. What makes subduction zones form is not known. What is known is that a major subduction zone vanished when India collided with Asia, and no new subduction zones formed elsewhere to take its place. If this conjecture is true, plate tectonics will temporarily stop in a few hundred million years when the next supercontinent forms, only to restart later when too much heat stress builds up inside the planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is all highly conjectural. No scientist will live to see their conjectures falsified.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.chriscunnings.com/uploads/2/0/7/7/20773630/runaway_greenhouse_venus.pdf&quot;&gt;Kasting (1988), &quot;Runaway and moist greenhouse atmospheres and the evolution of Earth and Venus,&quot; &lt;em&gt;Icarus&lt;/em&gt; 74.3 : 472-494&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://adsabs.harvard.edu/abs/2003TrGeo...2..547M&quot;&gt;McDonough (2003), &quot;Compositional model for the Earth's core.&quot; In &lt;em&gt;Treatise on geochemistry 2&lt;/em&gt; 547-568&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencemag.org/content/319/5859/85&quot;&gt;Silver &amp;amp; Behn (2008), &quot;Intermittent plate tectonics?&quot; &lt;em&gt;Science&lt;/em&gt; 319.5859&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-11-19T19:22:53.143" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2853" PostTypeId="2" ParentId="2596" CreationDate="2014-11-19T19:51:08.513" Score="2" Body="&lt;p&gt;As taken from &lt;a href=&quot;https://en.wikipedia.org/wiki/Oceanic_trench&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;There are several factors that control the depth of trenches. The most important control is &lt;strong&gt;the supply of sediment&lt;/strong&gt;, which fills the trench so that there is no bathymetric expression. It is therefore not surprising that the deepest trenches (deeper than 8,000 m (26,000 ft)) are all nonaccretionary. In contrast, all trenches with growing accretionary prisms are shallower than 8,000 m (26,000 ft).&lt;/p&gt;&#xA;&lt;p&gt;A second order control on trench depth is &lt;strong&gt;the age of the lithosphere at the time of subduction&lt;/strong&gt;. Because oceanic lithosphere cools and thickens as it ages, it subsides. The older the seafloor, the deeper it lies and this determines a minimum depth from which seafloor begins its descent. This obvious correlation can be removed by looking at the relative depth, the difference between regional seafloor depth and maximum trench depth. Relative depth may be controlled by the age of the lithosphere at the trench, the convergence rate, and the dip of the subducted slab at intermediate depths.&lt;/p&gt;&#xA;&lt;p&gt;Finally, &lt;strong&gt;narrow slabs can sink and roll back more rapidly than broad plates&lt;/strong&gt;, because it is easier for underlying asthenosphere to flow around the edges of the sinking plate. Such slabs may have steep dips at relatively shallow depths and so may be associated with unusually deep trenches, &lt;strong&gt;such as the &lt;em&gt;Challenger Deep&lt;/em&gt;&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;br&gt;&#xA;&lt;p&gt;A simple picture for anyone who doesn't understand how these trenches form:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/oFeRh.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oFeRh.gif&quot; alt=&quot;Oceanic trench&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;sub&gt;(source: &lt;a href=&quot;https://sjesci.wikispaces.com/file/view/trench.gif/148041157/trench.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikispaces.com&lt;/a&gt;)&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;Also, the Mariana Trench isn't the only super deep trench in the ocean... &lt;a href=&quot;https://www.marineinsight.com/know-more/10-deepest-parts-of-the-ocean/&quot; rel=&quot;nofollow noreferrer&quot;&gt;10 deepest parts of the ocean&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="115" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-07-14T09:27:29.750" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="2854" PostTypeId="1" AcceptedAnswerId="2858" CreationDate="2014-11-19T20:59:55.473" Score="9" ViewCount="1451" Body="&lt;p&gt;This is the historical feed of the Keystone dam for October 2014:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.swt-wc.usace.army.mil/chartbin/KEYSOct14.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;www.swt-wc.usace.army.mil/chartbin/KEYSOct14.shtml&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Here is the real time feed:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.swt-wc.usace.army.mil/ops_hydropower/KEYShydro.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;www.swt-wc.usace.army.mil/ops_hydropower/KEYShydro.html&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I am having trouble understanding the &quot;Releases DSF&quot; Power/Total columns. What do these mean? I understand that DSF is day-second-feet but that is a unit of volume NOT flow rate. The real-time feed shows the flow rate in CFS (cubic feet/second). The dam is rated at around 70 MW. Do you think that the column in the historical data is mislabelled as Power when it should be Energy (MWh)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand that Power = Height of Dam x Flow Rate x Efficiency and this makes sense in the real-time feed. However, I am having trouble reconciling the historical data with the real time data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bottom line: I want to know the power / energy generated at the dam historically and in real time.&lt;/p&gt;&#xA;" OwnerUserId="1182" LastEditorUserId="5594" LastEditDate="2017-12-15T08:38:54.737" LastActivityDate="2017-12-15T08:38:54.737" Title="Interpreting some hydropower data. What does DSF mean in this context?" Tags="|hydrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2855" PostTypeId="1" AcceptedAnswerId="2861" CreationDate="2014-11-19T21:36:03.787" Score="36" ViewCount="3344" Body="&lt;p&gt;In continuation of the question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2830/why-is-earths-age-given-by-dating-meteorites-rather-than-its-own-rocks&quot;&gt;Why is Earth's age given by dating meteorites rather than its own rocks?&lt;/a&gt;, what evidence do we have that the asteroids indeed formed at the same time as earth? Is there any physical evidence, or is it a conclusion reached mostly through simulation?&lt;/p&gt;&#xA;" OwnerUserId="614" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-08-19T14:17:13.503" Title="How do we know the asteroids formed at the same time as earth?" Tags="|earth-history|planetary-science|geochemistry|geochronology|planetary-formation|" AnswerCount="5" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2856" PostTypeId="2" ParentId="2855" CreationDate="2014-11-19T21:42:15.957" Score="12" Body="&lt;p&gt;The formation of a T-Tauri star spells the beginning of the end of the protoplanetary disk from which planets and asteroids can form. The end is nigh when that star ignites. The large solar winds and solar radiation pressure sweep the disk clean of all small objects. Some spirals inward, some outward. There's no dust and no gas from which new planets and asteroids can form. All that can be done is a mopping-up of the not-so-small objects that escaped the solar wind and radiation pressure.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2014-11-19T21:42:15.957" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2857" PostTypeId="2" ParentId="2855" CreationDate="2014-11-20T02:39:15.363" Score="4" Body="&lt;p&gt;The age of 4.55Ga for the Earth is actually a date of &quot;hard stuff&quot; based on Iron-Nickel meteorites, dated using radio-isotope dating. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you had enough meteorite samples it should be possible to identify those with isotopes that imply a different age. For example, when plotted, their Pb isotope ratios will have different gradients. We do not see this.&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2014-11-20T02:39:15.363" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2858" PostTypeId="2" ParentId="2854" CreationDate="2014-11-20T04:11:48.133" Score="4" Body="&lt;p&gt;I think the DSF releases are both measures of releases. Neither is a measure of power. They are both a measure of the amount of water released, in day-second-feet, as you say.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The total column is the measure of the total amount of water released (in DSF). The power column is the amount of water released in order to generate power (in DSF). The difference between those two numbers is the amount of water (in DSF) released down the spillways (rather than to generate power), as part of overflow prevention, maintenance, or other activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the realtime feed, the column labelled power looks like mean power to me in MW: the dam rating is 70MW, and the power column maxes out at 70.267, so that does indeed look like MW. So that's the average over the quarter-hour. Multiply by 0.25 to get MWh.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;footnote rant:&#xA;Feet? Seriously? Feet? Who uses feet? What's wrong with these people?&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="100" LastEditDate="2014-11-20T13:25:08.347" LastActivityDate="2014-11-20T13:25:08.347" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2859" PostTypeId="2" ParentId="959" CreationDate="2014-11-20T05:28:33.727" Score="8" Body="&lt;p&gt;You can use Generic Mapping Tools (GMT): &lt;a href=&quot;http://gmt.soest.hawaii.edu/&quot; rel=&quot;noreferrer&quot;&gt;http://gmt.soest.hawaii.edu/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It's a command line tool for (among other things) plotting maps and geographical data. Works best on Linux/Mac but also on Windows.&lt;/p&gt;&#xA;&lt;p&gt;Here's an example. Running this code generates a map:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;gmt pscoast -R0/360/-80/85 -JM20 -B20/10 -Di -Glightbrown -Slightblue -Wblack &amp;gt; merc.ps&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;And this will convert to png:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;ps2raster merc.ps -Tg -A -P&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Resulting in this:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/bun7c.png&quot; alt=&quot;Mercator world&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;It's highly customisable and easy to use!&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-11-20T05:28:33.727" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2860" PostTypeId="1" AcceptedAnswerId="2868" CreationDate="2014-11-20T07:53:10.957" Score="10" ViewCount="11996" Body="&lt;p&gt;I have always wondered how someone could tell, by a brief observation (a few minutes at most), whether a tide is receding or advancing on a rainy day.  Assuming there is no access to tide times and the ground is completely wet due to the weather.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason why I am emphasising a rainy day, is due to the wet sand on the ground, on a dry day, wet sand would indicate whether the tide is going in or out. On a rainy day, everything is wet, no way of telling.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there immediate waveforms or wave behaviour that could determine the direction of the tide?&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="111" LastEditDate="2014-11-20T20:42:09.770" LastActivityDate="2014-11-22T20:01:58.563" Title="What visual wave behaviour help to tell if a tide is going in or out?" Tags="|ocean|waves|ocean-currents|tides|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2861" PostTypeId="2" ParentId="2855" CreationDate="2014-11-20T08:07:26.363" Score="36" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;what evidence do we have that the asteroids indeed formed at the same time as earth?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It depends on what is your definition as &quot;the same time&quot;. The formation of the solar system and Earth did not happen at a particular second in time but was rather a continuous process. It also depends on what you define as &quot;asteroids&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll try to put some things in order.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The oldest known material from Earth is a zircon from the Jack Hills in Australia. Its age has been recently refined to be 4382 million years. We know that because we measured it.&lt;sup&gt;(1)&lt;/sup&gt;&lt;/li&gt;&#xA;&lt;li&gt;The moon forming event occurred sometime between 4348 and 4413 million years ago.&lt;sup&gt;(2)&lt;/sup&gt; Now, that zircon should be younger than the moon (because the moon forming event would destroy any already-existing minerals on Earth). Yet, there is a slight overlap between the ages. This is due to the fact that analytical capabilities have their uncertainties and error.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;This means that the Earth has been here at least ~4.4 billion years ago, because you need the Earth to have a moon. The Earth didn't just pop into existence, but it formed over a period of time, in which small planetesimals collided with each other and accreted to form a larger body. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question now is, what is the age of the planetesimals? We can't know for sure because they are all integrated into Earth, but we can look at asteroids and see their age. We do that by dating the meteorites that fall on the Earth, which in some cases are blasted off asteroids by (even more) collisions and impacts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you look inside a specific type of meteorites called &lt;em&gt;chondrites&lt;/em&gt;, you can see objects that are called &lt;em&gt;CAI&lt;/em&gt;s (calcium-aluminum inclusions). These things are solids condensed from vapourised gas that existed in the solar nebula before any planets and planetesimals formed. These are basically the first solid to form in the solar system, and they define the birth of the solar system. We know that they formed 4568&lt;sup&gt;(3,4)&lt;/sup&gt; or 4569.5&lt;sup&gt;(5)&lt;/sup&gt; million years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Planetary bodies (which for this discussion will be considered as km-sized chucks or rock with the ability to melt and differentiate to mantle and crust, and accrete to form proper planets) began forming around 4566.2 to 4567 million years ago&lt;sup&gt;(5,6,7)&lt;/sup&gt;. We know that because we can date meteorites that we know originated in asteroids. This is just 2 million years after the formation of the first solid droplets in the solar system. Now, while 2 million may seem like a long time for your daily commute, it is not too long for planetary processes (considering Earth is 4.5-4.4 &lt;em&gt;billion&lt;/em&gt; years old).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now there is a time gap - what happened between 4566 (formation of planetesimals and asteroids) and 4413 (formation of the moon)? There are about 150 million years that I haven't talked about yet. Was the Earth gradually growing in a linear fashion during that time or did it form rather quickly? Luckily, there are answers to that as well. Based on some measured geochemical data it was shown that most of Earth's mass actually accreted ~10 million years after the formation of the solar system(8). That's rather quick! So the Earth has been sitting there, all by itself, around 100 million years until the moon formed. As to how the Earth itself formed, it could be just amalgamation of small planetisimals, collision of larger bodies, or something completely else. Chemical evidence and physical models do not always agree, and it's all highly debated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a field which is rapidly evolving and discoveries are made all the time due to better analytical capabilities and better models. Just look at the years of the papers below. This is all cutting edge and a highly exciting field of study. Everything that I wrote here can be inaccurate or even plain wrong, but that's the fun in science.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is there any physical evidence, or is it a conclusion reached mostly through simulation?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So it is a combination of both. You find physical evidence: rocks from Earth and parts of meteorites and their minerals. You measure their isotopic composition to find their age and other characteristics. Then you make a model (or a simulation) that tries to see what has to happen in order for the physical properties to agree.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Further reading:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://cms.ku.dk/upload/application/pdf/990825ad/engelsk.pdf&quot; rel=&quot;noreferrer&quot;&gt;An introduction to Meteorites and the origin of the Solar System&lt;/a&gt; - a very accessible and interesting read.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://dx.doi.org/10.2113/gselements.7.1.41&quot; rel=&quot;noreferrer&quot;&gt;Chronometry of Meteorites and the Formation of the Earth and Moon&lt;/a&gt; - a more technical review, may be paywalled.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;hr&gt;&#xA;Refs:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&#xA;1 Valley, J. W., Cavosie, A. J., Ushikubo, T., Reinhard, D. A., Lawrence, D. F., Larson, D. J., … Spicuzza, M. J. (2014). Hadean age for a post-magma-ocean zircon confirmed by atom-probe tomography. &lt;em&gt;Nature Geoscience&lt;/em&gt;, 7(3), 219–223. doi:10.1038/ngeo2075&#xA;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&#xA;2 Carlson, R. W., Borg, L. E., Gaffney, A. M., &amp;amp; Boyet, M. (2014). Rb-Sr, Sm-Nd and Lu-Hf isotope systematics of the lunar Mg-suite: the age of the lunar crust and its relation to the time of Moon formation. &lt;em&gt;Philosophical Transactions. Series A, Mathematical, Physical, and Engineering Sciences&lt;/em&gt;, 372(2024), 20130246. doi:10.1098/rsta.2013.0246&#xA;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&#xA;3 Bouvier, A., &amp;amp; Wadhwa, M. (2010). The age of the Solar System redefined by the oldest Pb–Pb age of a meteoritic inclusion. &lt;em&gt;Nature Geoscience&lt;/em&gt;, 3(9), 637–641. doi:10.1038/ngeo941&#xA;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&#xA;4 Burkhardt, C., Kleine, T., Bourdon, B., Palme, H., Zipfel, J., Friedrich, J. M., &amp;amp; Ebel, D. S. (2008). Hf–W mineral isochron for Ca,Al-rich inclusions: Age of the solar system and the timing of core formation in planetesimals. &lt;em&gt;Geochimica et Cosmochimica Acta&lt;/em&gt;, 72(24), 6177–6197. doi:10.1016/j.gca.2008.10.023&#xA;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&#xA;5 Baker, J., Bizzarro, M., Wittig, N., Connelly, J., &amp;amp; Haack, H. (2005). Early planetesimal melting from an age of 4.5662 Gyr for differentiated meteorites. &lt;em&gt;Nature&lt;/em&gt;, 436(7054), 1127–31. doi:10.1038/nature038825&#xA;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;6 Greenwood, R. C., Franchi, I. A., Jambon, A., &amp;amp; Buchanan, P. C. (2005). Widespread magma oceans on asteroidal bodies in the early Solar System. &lt;em&gt;Nature&lt;/em&gt;, 435(7044), 916–8. doi:10.1038/nature03612&lt;/sup&gt;&#xA;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&#xA;7 Amelin, Y., Kaltenbach, A., Iizuka, T., Stirling, C. H., Ireland, T. R., Petaev, M., &amp;amp; Jacobsen, S. B. (2010). U–Pb chronology of the Solar System’s oldest solids with variable 238U/235U. &lt;em&gt;Earth and Planetary Science Letters&lt;/em&gt;, 300(3-4), 343–350. doi:10.1016/j.epsl.2010.10.015&#xA;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&#xA;8 Rudge, J. F., Kleine, T., &amp;amp; Bourdon, B. (2010). Broad bounds on Earth’s accretion and core formation constrained by geochemical models. &lt;em&gt;Nature Geoscience&lt;/em&gt;, 3(6), 439–443. doi:10.1038/ngeo872&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2016-08-19T11:23:34.770" LastActivityDate="2016-08-19T11:23:34.770" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2862" PostTypeId="2" ParentId="2850" CreationDate="2014-11-20T08:39:07.093" Score="5" Body="&lt;p&gt;I'll add to Richard's contemporary answer and add that we have plenty of evidence for subducted plates in the geological past.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The evidence lies in the form of &lt;strong&gt;ophiolites&lt;/strong&gt;. Ophiolites are fossil fragments of oceanic lithosphere, that for some reason (which I will not go over in detail here), survive subduction and become obducted (a fancy antonym for subduction) and emplaced on the surface. They are mineralogically and structurally distinct from anything that might find on &quot;normal&quot; continental crust. There are all kinds of ophiolites, and most importantly for our discussion are the SSZ (supra-subuction zone) ophiolites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's look on the geographical distributions of ophiolites:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/nSuoB.gif&quot; alt=&quot;ophiolite map&quot;&gt;&#xA;&lt;sup&gt;(source: &lt;a href=&quot;http://instruct.uwo.ca/earth-sci/200a-001/09ophloc.gif&quot; rel=&quot;noreferrer&quot;&gt;http://instruct.uwo.ca/earth-sci/200a-001/09ophloc.gif&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see that they are distributed all over the Earth. Some are obvious, such as the ones near New Zealand, because they occur on top of a convergent boundary (&lt;em&gt;i.e.&lt;/em&gt; a subduction zone). Some are less obvious, for instance the ophiolites in Russia's Ural that sits in the middle of the continent. What this ophiolite represents is the past occurrence of oceanic crust between the west and east Eurasian continental plate, which amalgamated owing to the subduction of that (now long gone) oceanic lithosphere. Here's an example of how it happens:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/w9qX2.jpg&quot; alt=&quot;subduction&quot;&gt;&#xA;&lt;sup&gt;(sorry, no idea where this comes from)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So that piece of ocean between the continent and the continental fragment is subducted and lost forever, but you can see the remnant of it in the form of an ophiolite, represented by that sub-vertical thick black line. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another example, closer to me, is the Arabian ophiolite. You can't see it in this scale but it's actually a series of ophiolites, so called &quot;suture zones&quot;, where pieces of small continental crusts formed in an island arc settings get &quot;glued&quot; to the main continental crust.So on the one hand, you have the Alpine-Himalayan orogeny, closing the Tethys sea (of which the Mediterranean is a remnant), operating mostly in the Cenozoic (past ~65 million years), forming modern day ophiolites. On the other hand, not very far from there, you have remnants of past oceanic plates, embedded in the Proterozoic continental crust of the Arabian-Nubian shield (more than 600 million years ago). To complicate it even more, it is now being rifted, evident by the formation of the Red Sea. Geology is fun!&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2014-11-20T08:39:07.093" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2863" PostTypeId="1" CreationDate="2014-11-20T10:39:24.743" Score="8" ViewCount="3351" Body="&lt;p&gt;A Science Daily article &lt;a href=&quot;http://www.sciencedaily.com/releases/2011/07/110705104205.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Volcanic eruptions long overdue in SE Australia&lt;/a&gt; (University of Melbourne, 2011), suggests that a volcanic eruption is potentially &quot;long overdue&quot; in south-east Australia (south-west Victoria and the south-eastern part of South Australia).  As per the map below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/rslqK.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.kanawinkageopark.org.au/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bernie Joyce, of Melbourne University, has studied the late Palaeogene-Quaternary volcanoes in this region, the last eruption believed to have been at Mt. Gambier in South Australia, erupting about 5000 years ago (image below). His study revealed that the frequency of eruptions is about 1 every 2000 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/qV4d6.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://volcanoworld.wordpress.com/2012/01/05/has-there-ever-been-any-volcanic-activity-in-australia/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is clearly an example of intraplate volcanic activity, as the plate boundaries are a considerable distance away, as shown below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/JTPfE.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://eqinfo.ucsd.edu/special_events/solomon/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What evidence, other than the periodicity mentioned in the article, is there that a future volcanic eruption may occur in south-east Australia?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-11-21T21:51:57.570" LastActivityDate="2018-11-15T05:45:07.867" Title="Will a volcano erupt in Australia soon?" Tags="|volcanology|volcanoes|volcanic-hazard|intraplate|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2864" PostTypeId="2" ParentId="2850" CreationDate="2014-11-20T10:41:45.100" Score="7" Body="&lt;p&gt;As a complement to the two other answers, the work of &lt;strong&gt;&lt;a href=&quot;http://www.geologist.nl/images/2012_vanderMeer_NatGeo.pdf&quot; rel=&quot;noreferrer&quot;&gt;van de Meer et al., 2012&lt;/a&gt;&lt;/strong&gt; is worth mentioning. In this article, the authors tried to explore the Triassic-Jurassic plate tectonic evolution of the Panthalassa Ocean (currently all remaining oceanic crust in the Pacific Ocean is Cretaceous or younger).&lt;br&gt;&#xA;They localized a serie of paleo-subduction zones (that they called Telkhinia) using paleo-volcanic arcs that are now accreted to the north American and east Asian continents. Additionally they used seismic-wave tomographic models of the mantle to identify the remnants of the subducted plate.&lt;br&gt;&#xA;In their reconstruction the Panthalassa is thus divided in two oceanic plates, Pontus and Thalassa ocean, Pontus being the one that got completely subducted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/sXT8G.png&quot; alt=&quot;Paleogeographic reconstruction of the Pontus Ocean ca. 200 Ma.&quot;&gt;&#xA;&lt;sub&gt;Paleogeographic reconstruction of the Pontus Ocean ca. 200 Ma. Credit: Douwe van der Meer.&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Source:&lt;br&gt;&#xA;van de Meer, D. G., Torsvik, T. H., Spakman, W., van Hinsbergen, D. J. J. and Amaru, M. L. 2012. &lt;a href=&quot;http://dx.doi.org/10.1038/ngeo1401&quot; rel=&quot;noreferrer&quot;&gt;Intra-Panthalassa Ocean subduction zones revealed by fossil arcs and mantle structure&lt;/a&gt;. Nature Geoscience, 5: 215-219.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-11-20T10:50:51.900" LastActivityDate="2014-11-20T10:50:51.900" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2865" PostTypeId="1" CreationDate="2014-11-20T12:50:27.627" Score="12" ViewCount="123" Body="&lt;p&gt;The UK legislator with primary responsibility for energy has claimed that exhausted fracked natural-gas wells will be suitable for re-use as a geothermal energy supply (not necessarily geothermal for electricity production, but rather for heat distribution, so let's say 80&amp;deg; - 250&amp;deg;C).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there much of a co-location of the geo-thermal resource in the UK, with the more easily obtained frackable natural gas; and would an exhausted fracked well be structurally suitable for this?&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="100" LastEditDate="2014-11-20T18:37:10.177" LastActivityDate="2014-11-21T12:36:50.170" Title="viable geothermal energy supply from exhausted fracked gas wells?" Tags="|geology|geothermal-heat|economic-geology|fracking|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2866" PostTypeId="1" AcceptedAnswerId="2867" CreationDate="2014-11-20T14:08:06.537" Score="12" ViewCount="239" Body="&lt;p&gt;Reading &lt;em&gt;Introduction to Geology&lt;/em&gt; (MIT 2005) and Wikipedia's article on Earth's inner core, it is specified that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Earth was discovered to have a solid inner core distinct from its liquid outer &#xA;  core in 1936, by the seismologist Inge Lehmann, who deduced its presence from observations of earthquake-generated seismic waves that reflect off the boundary of the inner core and can be detected by sensitive seismographs on the Earth's surface.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Why does seismic activity would result in the conclusion that the inner core is rigid? What is the link between seismism and inner core?&lt;/p&gt;&#xA;" OwnerUserId="1138" LastEditorUserId="725" LastEditDate="2014-11-20T17:18:11.197" LastActivityDate="2014-11-20T19:15:03.167" Title="Why does seismic activity shed light on the inner core rigidity?" Tags="|geophysics|seismology|core|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2867" PostTypeId="2" ParentId="2866" CreationDate="2014-11-20T16:28:50.963" Score="8" Body="&lt;p&gt;The question that Azzie Rogers linked to: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/517/how-can-we-guess-the-size-of-the-earths-inner-coreand-what-its-made-of/518&quot;&gt;How can we determine the size and composition of Earth&amp;#39;s inner core?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does answer the theory part of the question, but I will extrapolate a little more to answer the question. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question becomes, what kind of waves travel through what? Both shear and compressional seismic waves can travel through solids, but as it turns out, you cannot shear a liquid. As you look at teleseismic raypaths (waves traveling far from the source) you can see that the wave must travel deep into the earth and then back up again. The wave forms, and directions of these wavepaths will be altered by the different compositions of Earth's layers as it travels through: a wave just traveling through the mantle will have both its shear and compressional component.  A wave traveling through the mantle and outer core will lose its original shear component, and either develop a new one as it leaves the core (but distinct from the wave that travels through the mantle only) or not have one at all. And finally, a wave that travels through the mantle, outer core and inner core will have distinct wave patters as well. Its by this comparison of waveforms that we realize that the earth not only has different compositional layers, but phase boundaries as well. I am not sure seismology alone would lead to a solid inner core, but there is abundant evidence  supporting that fact. When you combine Seismology, rare bits of geochemistry, the calculation of Earth's gravity , and perhaps the most important part, the magnetic dynamo generating our magnetic field, we see a fairly clear ( albeit incomplete) story.   &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-11-20T19:15:03.167" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2868" PostTypeId="2" ParentId="2860" CreationDate="2014-11-20T20:24:15.547" Score="12" Body="&lt;p&gt;As SimonW points out strong tidal currents will modify the wave shape and significant height.  The &lt;a href=&quot;http://dx.doi.org/10.1016/S0378-3839(99)00039-3&quot; rel=&quot;noreferrer&quot;&gt;Wolf &amp;amp; Prandle (1999)&lt;/a&gt; study provides a neat summary description of the effects of currents (of any kind) on waves: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;(i) Wave generation by wind—the effective wind is that relative to the surface current, and the wave age (cp/U*) and effective surface roughness may be important, e.g., Janssen (1989). Here cp is the wave phase speed and U* is the friction velocity of the wind. The effective fetch also changes in the presence of a current.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;(ii) Wave propagation—the effects of depth refraction are easy to spot, turning the mean wave direction towards shore-normal. Current refraction has a more subtle effect, dependent on the spatial variation of currents, whether decreasing or increasing towards the coast. Generally shoaling depths will increase the tidal amplitude towards the coast until friction reverses this trend. The waves will tend to turn towards the direction of the current axis.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;(iii) Doppler shift—the effect of a steady current on intrinsic (relative) wave frequency. Waves of the same apparent (absolute) period will have a longer intrinsic period in a favourable (following) current and a shorter intrinsic period in an opposing current.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;(iv) Steepening of waves on an opposing current (related to (iii)), due to shorter wavelength and increased wave height from wave action conservation.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;(v) Modulation of absolute frequency by unsteady currents and modulation of intrinsic frequency by propagation over spatial gradients of current. If the current is steady the absolute frequency should be constant, if the current is homogeneous the intrinsic frequency should be constant. If both intrinsic and absolute period show a tidal modulation, the currents must be effectively inhomogeneous and unsteady.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;(vi) Wave–current bottom stress. Various empirical theories for wave–current interaction in the bottom boundary layer suggest that the friction coefficient experienced by waves in a current regime will be larger than in no current. This also applies to the effective current friction factor in the presence of waves.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;(vii) Effect of vertical current shear on wave breaking. Wind-driven surge currents would be relevant to this, the tidal currents have no surface shear.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I think the most &quot;observable&quot; of this effects from a &quot;brief rainy day observation&quot; will be their #4 effect. The steepening of waves as they oppose the current can be observed relatively easily. Care must be taken though when interpreting item #4: In steady (constant in time) and homogeneous (constant in space) current, the wavenumber remains unchanged, only the apparent (absolute) frequency and phase speed change:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\omega = \sigma + \mathbf{k}\cdot\mathbf{U}\\&#xA;$$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;C_p = C_{p0} + U&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\omega$ and $\sigma$ are the apparent and intrinsic frequencies, respectively, $k$ is the directional wavenumber vector and $U$ is the current vector. $C_{p}$ and $C_{p0}$ are apparent and intrinsic phase speeds, respectively. Due to the conservation of wave crests that says:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\dfrac{\partial k}{\partial t} + \dfrac{\partial\omega}{\partial x} = 0&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;wavenumber, and thus the steepness of the wave can change only in unsteady or non-homogeneous current field, in absence of other effects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, visually, steepness is not the only property of the waves that can reveal strong underlying current. For example, in absence of swell and in presence of strong Eulerian currents and light intermittent wind, small wind-generated ripples can be observed to form on the surface. These waves are almost capillary, very short and low, and propagating slowly. The direction of their propagation can be identified visually because the front face of the wave is steeper than the rear. In presence of strong Eulerian flow against the direction of wind, the whole patch of these short waves can be observed to move backward, rather than forward, thus revealing the direction of the underlying current.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a similar but different effect, underlying Eulerian flow can be identified in a situation where the current increases to the point where it equals the opposing group velocity of the waves. Since the wave energy is advected with group velocity, they cannot propagate beyond this point, and usually a line the divides the two regimes can be seen: one side with smooth surface without waves, and the other where waves are present, propagating toward the line but steepening and whitecapping when reaching the line. This physical process is known as wave blocking. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another &lt;a href=&quot;http://www.seleneowners.org/SO_news.php?newsid=29&quot; rel=&quot;noreferrer&quot;&gt;classic example&lt;/a&gt; is the mouth of the Columbia River, where the waves during ebb tide become so steep they often break along the &lt;a href=&quot;http://en.wikipedia.org/wiki/Columbia_Bar&quot; rel=&quot;noreferrer&quot;&gt;Columbia River Bar&lt;/a&gt;. During strong ebb tides, large ocean waves, especially swells, become larger, steeper, and also they come closer together. The resulting dangerous conditions change rapidly as the tide turns to flood with waves being smaller and less steep.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/qYxFp.jpg&quot; alt=&quot;During times of maximum ebb current, seas can become extremely steep with breaking waves.&quot;&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One study that looked at the effect on wave height is &lt;a href=&quot;http://dx.doi.org/10.1175/JPO-D-12-043.1&quot; rel=&quot;noreferrer&quot;&gt;Gemmrich &amp;amp; Garrett (2012)&lt;/a&gt;. The attached figure from their paper &lt;a href=&quot;https://i.stack.imgur.com/YPy2y.jpg&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt; shows how the significant wave height is affected (modulated) by the normalized tidal speed. Larger waves occur during times of larger tidal currents. &lt;img src=&quot;https://i.stack.imgur.com/YPy2y.jpg&quot; alt=&quot;The figure shows 19-day segments of modulations of significant wave height overlaid on the east–west component of the barotropic tidal currents u, normalized by the maximum barotropic tidal speed&quot;&gt;. The theoretical considerations can be found in &lt;a href=&quot;http://dx.doi.org/10.1175/1520-0485(1990)020%3C1166:TIOUDA%3E2.0.CO;2&quot; rel=&quot;noreferrer&quot;&gt;Tolman (1990)&lt;/a&gt; where a thorough explanation of the changes in surface wave amplitude, direction, and frequency caused by currents. Other studies looking at wave height modulation include &lt;a href=&quot;http://dx.doi.org/10.1029/93JC01440&quot; rel=&quot;noreferrer&quot;&gt;Thornton &amp;amp; Kim (2012)&lt;/a&gt; and &lt;a href=&quot;http://dx.doi.org/10.1016/S0378-3839(99)00039-3&quot; rel=&quot;noreferrer&quot;&gt;Wolf &amp;amp; Prandle (1999)&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="192" LastEditDate="2014-11-22T20:01:58.563" LastActivityDate="2014-11-22T20:01:58.563" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="2869" PostTypeId="2" ParentId="2855" CreationDate="2014-11-20T21:04:56.973" Score="3" Body="&lt;p&gt;The fact that the overwhelming majority of celestial objects within our solar system orbit in a like manner (same direction as the Sun's rotation) is observational evidence that they formed at about the same time from the same processes. A rogue planet/proto-planet/asteroid captured by our solar system's gravitational footprint in space time would have a 50/50 chance of developing an orbit in the same direction. If that was a retrograde orbit, its chances of survival would be considerably less. Think of a single NASCAR driver deciding to race in the wrong direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm certainly not saying that odd things in orbital mechanics don't happen and while our solar system has calmed down quite a bit from its earlier catastrophically chaotic days, it is currently believed by a growing number of scientists that &lt;a href=&quot;http://researchmatters.asu.edu/stories/solar-system-swap-uranus-and-neptune-switched-places-842&quot; rel=&quot;nofollow&quot;&gt;Neptune and Uranus swapped orbital paths&lt;/a&gt; due to a harmonic gravitational tug from Jupiter and Saturn and an exo-planet with a retrograde solar orbit (&lt;a href=&quot;http://phys.org/news/2011-06-planet-wrong.html&quot; rel=&quot;nofollow&quot;&gt;WASP-17b&lt;/a&gt;) was either a rogue planet captured by its solar system or its orbit was flipped into a counter solar spin direction from a near collision with another object.&lt;/p&gt;&#xA;" OwnerDisplayName="user1193" LastActivityDate="2014-11-20T21:04:56.973" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2870" PostTypeId="2" ParentId="2855" CreationDate="2014-11-21T05:35:33.557" Score="-3" Body="&lt;p&gt;Perhaps a little step back to get a bigger point of view is required.&#xA;Take note of this line in the answer provided by Michael - &quot;it might be plain wrong&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question uncovers some very glaring assumptions:&#xA;1. We know how the earth was formed.&#xA;2. We know when the earth was formed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The current theory of accretion doesn't hold much water - both metaphorically and literally speaking. &#xA;There just is no way that dust or rocks in space can accrete all by itself to form a body such as the earth. Even basic physics disagrees with this. The simulations have to ignore this basic fact and instead introduce fudge factors to make rocks and dust &quot;stick&quot; together when the collide. &#xA;You just go out and try making rocks stick together when they smash into each other - confirm for yourself whether it will work in space where there's even less resistance to flying apart.&#xA;Furthermore, even if one allows for some miraculous hot sludge of radioactive material to stick together, one immediately creates another problem: the exclusion of water because of heat.&#xA;There is no acceptable way for all the water on earth to arrive here from outer space. Why would the water only strike earth [ and where would it come from in the first place ] in such a way that Mars, Venus and the moon do not have any evidence of a watery bombardment?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then there's the question of how does one measure the age of anything? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Age is unfortunately not a physical property that we can measure directly like length, volume, density, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to know the age of anything one needs to have been present when it came into existence and then to have some way by which to assign some kind of measure of passage of time to it. &#xA;In short - age is an abstract construct that cannot be measured physically.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What can be measured is the proportions of the number of atoms of mother and daughter products of radioactive material. But having established that proportion and applying a rate of decay to determine age doesn't give a true age. &#xA;Have you ever found a record of calibration that confirms that the radioactive methodology does indeed deliver the correct age? Did someone witness and record the creation of basic radioactive rock and then track it's age using the radioactive decay method? To my mind, it hasn't been done and in fact where some measurements have been made of newly created basalt in St Helen's eruption, the ages produced are plain incorrect.&#xA;The best that it can produce is an &quot;age&quot; based on some very questionable assumptions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since we do not know the history of the earth we need to make some assumptions regarding its creation. We need some form of &quot;clock&quot; by which we can measure how old the earth is. That clock has to be independent of the earth itself, hence why people use meteoroids, under the assumption that it must be at least as old as if not older than the earth itself. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main problem is that we need to know when that clock started ticking and we just don't have any means to establish an objective way to determine that.&#xA;No one was there to witness and record that event. There-in lies the problem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even if you assume that the radio-active decay happened at a constant rate[ which we have seen is now no longer true ], you still have to make assumptions about the quantities involved. But therein lies another problem - you don't know the origin and history of the original material - how long did IT exist before it started its radioactivity?&#xA;One can go on ad-infinitum.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in spite of the highly &quot;scientific&quot; answer provided by Michael, the fact is that one cannot determine the age of the earth without making some highly metaphysical assumptions about the origin of the universe. You have to make some questionable unsubstantiated assumptions as to how the whole universe came into being. &#xA;It cannot be determined scientifically, in spite of using the latest and greatest technology in cosmology today.&#xA;We simply weren't there. We have no eye-witness account. We have no record.&#xA;The best we can do is make assumptions of the starting point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You may not like this answer. You may even get angry at seeing it but unfortunately for you, you cannot push it's validity out of the way. &lt;/p&gt;&#xA;" OwnerUserId="1194" LastEditorUserId="1194" LastEditDate="2014-11-21T06:17:52.437" LastActivityDate="2014-11-21T06:17:52.437" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2871" PostTypeId="1" AcceptedAnswerId="2873" CreationDate="2014-11-21T12:06:26.930" Score="8" ViewCount="681" Body="&lt;p&gt;The Paleocene-Eocene Thermal Maximum (PETM) is a well-studied warming event near the Paleocene-Eocene boundary.&lt;br&gt;&#xA;It is characterized by its extreme warming rate: from onset to recovery the event lasted ca. 100 kyrs, and the global temperature is thought to have increased by ~6 °C in barely 20 kyrs.&lt;br&gt;&#xA;This event is of particular interest not only for its $\delta^{18}\rm O$ but also a sharp negative excursion in the $\delta^{13}\rm C$, implying a strong input of $^{13}\rm C$-depleted carbon into the system.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/UmI5m.png&quot; alt=&quot;Isotopic curves of Paleogene climate, showing abrupt peak at PETM&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Simplified and redrawn after Zachos et al. 2001&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One frequently invoked hypothesis to explain this input is the leakage of methane from clathrates trapped in seafloor sediments.&lt;br&gt;&#xA;Being a paleontologist and not a geochemist, I struggle to understand the actual chemical mechanism involved.&#xA;&lt;strong&gt;I was thus wondering if someone could explain the mechanisms allowing the destabilization of methane clathrates at the same time on a global scale.&lt;/strong&gt;&lt;br&gt;&#xA;If it's just linked to a temperature threshold, how come it wasn't reach prior to that (warmer temperature were reached during the Cretaceous)?&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="6129" LastEditDate="2020-05-06T08:27:16.060" LastActivityDate="2020-05-06T08:27:16.060" Title="Release mechanism for methane clathrate at the PETM" Tags="|geochemistry|paleoclimatology|clathrates|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2872" PostTypeId="2" ParentId="2865" CreationDate="2014-11-21T12:36:50.170" Score="4" Body="&lt;p&gt;Viability of an oil or gas well for geothermal energy production is dependent upon several factors:&lt;br&gt;&#xA; - Geothermal heat profile with depth near the well &#xA; - Depth of the exhausted well&#xA; - Volume of fluid acting as a heat exchange around and near the well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think it might be possible to use exhausted natural-gas wells will be suitable for re-use as a geothermal energy supply. Likelihood of success would require site investigation and the engineering pilot study.  This idea would be ideal for university engineering / geology research. &lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2014-11-21T12:36:50.170" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2873" PostTypeId="2" ParentId="2871" CreationDate="2014-11-21T13:31:28.120" Score="6" Body="&lt;p&gt;There seems to be some uncertainty as to the cause and mechanism for the PETM.  In the Science Daily article &lt;a href=&quot;http://www.sciencedaily.com/releases/2011/11/111109111542.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Methane may be answer to 56-million-year question: Ocean could have contained enough methane to cause drastic climate change&lt;/a&gt; (2011) reporting research from Rice University, they claim that the seafloor was already warmer, thus according to their models:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;if the oceans were warmer, they would contain less dissolved oxygen and the kinetics for methane formation would have been faster.&#xA;  With less oxygen to consume organic matter on the way down, more sank to the ocean floor, Gu said, and there, with seafloor temperatures higher than they are today, microbes that turn organic matter into methane work faster.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Thus, they claim, the amount methane in the form of clathrates would have been approximately the same amount as today, but in a thinner stability zone.  They are not clear about what caused the destabilisation, but made the analogy of a charging-discharging capacitor (shown below, from the same source):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Dq7DM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A recent article &lt;a href=&quot;http://clim-past.net/10/759/2014/cp-10-759-2014.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;A seasonality trigger for carbon injection at the Paleocene–Eocene&#xA;Thermal Maximum&lt;/a&gt; (Eldrett et al. 2014) details of research into what vegetation eisted at the time to determine the species that were present in the time leading up to the PETM (or CIE = Carbon Isotope Excursion), they found that the seasons were already becoming warmer prior to the CIE (which led to the PETM).  The reason for the seasonal warming trend is modelled by the authors as being due to&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;enhanced seasonal contrasts through Milankovitch forcing&#xA;  (Lourens et al., 2005)*, combined with a gradually warming&#xA;  late Paleocene to early Eocene, forced a non-linear response&#xA;  in ocean circulation to warm intermediate waters.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Implying that orbital influences may have had a role in causing the increased seasonal warming leading up to the CIE.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They conclude that the modelled seasonal extremes prior to the onset of the CIE&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;represent the smoking gun of a climatologically forced&#xA;  threshold in the carbon cycle that caused the PETM.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Essentially by destabilising and altering the stability zone (as shown in the diagram above).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your question about the Cretaceous raises an important point presented in the earlier article &lt;a href=&quot;http://www.whoi.edu/cms/files/higgins06epsl_138364.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Beyond methane: Towards a theory for the Paleocene–Eocene&#xA;Thermal Maximum&lt;/a&gt; (Higgins and Schrag, 2006), who suggested that the carbon released from methane clathrates would not have been sufficient for the warming experienced during the PETM. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;High global sea-level&#xA;  and flooded continental interiors in the Cretaceous and&#xA;  early Tertiary may have also reduced the export of&#xA;  organic carbon from the shelves to the continental slope&#xA;  by promoting sedimentation on continental shelves that&#xA;  were 75% larger than present&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;suggesting that there was not enough methane clathrate, that it was 'building up' during the Cretaceous and early Palaeogene.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.nature.com/nature/journal/v435/n7045/abs/nature03814.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Astronomical pacing of late Palaeocene to early Eocene global warming events&lt;/a&gt; (Lourens et al. 2005) (Abstract only).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-11-21T15:47:14.947" LastActivityDate="2014-11-21T15:47:14.947" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2874" PostTypeId="2" ParentId="1053" CreationDate="2014-11-21T17:19:27.640" Score="6" Body="&lt;p&gt;High permeability (K) values for rock /sediment would be 1x10+2 to 1x10+5 (darcy)&#xA;The table below shows permeability values for sand/gravel packs placed around the well screen.  Well Screen itself would have even higher K values.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would say, that well screen itself (not including the sand and gravel pack around the well screen) will not limit the results of slut test results.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Essentially, for the well screen to limit slug test results, you need to place the well into a large cave or min void and the use a very large slug volume if you hope to measure the screen itself.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: Permeability values can approach very large values in limestone with caves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: my answer assumes that the well construction materials and methods are known that were used to install the well being tested.  I am also assuming the well has a manufactured well screen not a piece of pipe with 3 hack saw cuts to allow water to flow. Not knowing the well configuration, can reduce the accuracy of slug test results. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/jA2WO.png&quot; alt=&quot;Permeability of Gravel-pack sands&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://petrowiki.org/Gravel_pack_design&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source: Petrowiki&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="20" LastEditDate="2019-12-06T05:06:32.207" LastActivityDate="2019-12-06T05:06:32.207" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="2875" PostTypeId="1" AcceptedAnswerId="2880" CreationDate="2014-11-22T00:17:30.440" Score="8" ViewCount="385" Body="&lt;p&gt;I remember reading an article where a scientist was able to make a spinning iron tube with liquid nickel inside and it created a magnetic field, providing a laboratory-scale simulation of the generation of the Earth's magnetic field by convection in the outer core. I can't find any reference to this work on the web. I would like to find documents about such projects and see whether there have been any updates on the research.  &lt;/p&gt;&#xA;" OwnerUserId="1203" LastEditorUserId="94" LastEditDate="2014-11-22T15:05:41.163" LastActivityDate="2019-08-13T17:18:11.627" Title="Laboratory simulation of the Earth's magnetic field" Tags="|geophysics|geomagnetism|convection|laboratory|magnetosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2876" PostTypeId="2" ParentId="979" CreationDate="2014-11-22T04:08:39.617" Score="4" Body="&lt;p&gt;The University of Arizona's South West Climate Network webpage &lt;a href=&quot;http://www.southwestclimatechange.org/climate/southwest/precipitation-changes&quot; rel=&quot;nofollow&quot;&gt;Precipitation Changes&lt;/a&gt;  (Lenart, 2008) provides a detailed account of the causes of the warming in Arizona and the south-west region of the United States.  Principally, a major factor to consider is that the region is already arid, with low precipitation and high temperatures to begin with.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to Lenart, global climate models predict that precipitation in the region is expected to drop in the region by between 5-10% by the end of the century.  Less rainfall, coupled with higher temperatures would cause an increase in dryness, hence droughts and sudden downpours.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mechanism behind this precipitation drop is described by Lenart as being due to an increase in the area under the Hadley Cell circulation, resulting in a movement of the jet stream further north - resulting in winter storms bypassing the southwest altogether.  Some of the models predict there would be a northward shift of the subtropical anticyclone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So how do these models match the observations?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Observations and measurements have found that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;lower precipitation rates in the Southwest correlated with positive phases of the atmospheric pattern known as the Northern Annular Mode (NAM), which they attributed to an associated northward shift of the jet stream during these years. Meanwhile, the Rocky Mountains, headwaters of the Colorado and Rio Grande rivers, tended to register higher precipitation rates during these positive phases, consistent with the observation that the jet stream was shifting north.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, extreme precipitation events, such as the record breaking September, 2014 &lt;a href=&quot;http://www.nbcnews.com/news/weather/wettest-day-record-phoenix-flooding-leaves-2-dead-n198201&quot; rel=&quot;nofollow&quot;&gt;floods in Phoenix&lt;/a&gt;, as the remains of Hurricane Norbert swept through, are increasingly likely.  Crucially, from Lenart:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Precipitation records contain a &lt;strong&gt;high degree of variability&lt;/strong&gt;, however, as they are influenced by a variety of other factors in addition to climate change. For instance, much of the upward trend in the precipitation record from 1950 probably stemmed from an abundance of El Niño events in the second half of the record, according to Martin Hoerling, the researcher who conducted the analysis.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;An interesting and somewhat ironic twist implied in the document &lt;a href=&quot;http://www.climatecentral.org/wgts/heat-is-on/HeatIsOnReport.pdf&quot; rel=&quot;nofollow&quot;&gt;The Heat Is On: U.S. Temperature Trends&lt;/a&gt; is a speculative point that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;points out that since cleanair&#xA;  regulations have dramatically reduced these&#xA;  emissions over the past 20-30 years, the cooling&#xA;  e&quot;ect has already disappeared and will no longer&#xA;  be a factor in the future. If the study’s findings turn&#xA;  out to be applicable to the warming hole, &lt;strong&gt;then it&#xA;  is possible that without aerosols screening solar&#xA;  radiation these regions will catch up.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Anthropogenic sources, including land use can, according to the article &lt;a href=&quot;http://www7.nau.edu/mpcer/direnet/publications/publications_s/files/Swetnam_Betancourt_1998.pdf&quot; rel=&quot;nofollow&quot;&gt;Mesoscale Disturbance and Ecological Response to Decadal Climatic Variability in the&#xA;American Southwest&lt;/a&gt; (Swetnam and Betancourt, 1997), can amplify, mute or be utterly confounded by anthropogenic effects.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-11-22T04:08:39.617" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2877" PostTypeId="1" CreationDate="2014-11-22T08:36:39.420" Score="0" ViewCount="672" Body="&lt;p&gt;I know that it is calcium carbonate (CaCO&lt;sub&gt;3&lt;/sub&gt;). I also know that these are the dead bodies of microorganisms. &#xA;&lt;p&gt;&#xA;My question is, where do they procure the building material? The limestone seems to cover the whole Planet with a multimeter-thick layer. How is this possible - after we assume the conservation of atoms? Where did the limestone molecules come from? How long can the process of sediment formation last? Is the building material coming from space or due to Universe Expansion (black matter)? Is it right that the Planet becomes thicker and thicker with every year if we assume conservation of matter?&lt;/p&gt;&#xA;" OwnerUserId="1206" LastEditorUserId="725" LastEditDate="2017-03-14T21:20:39.650" LastActivityDate="2017-03-14T21:20:39.650" Title="What is limestone made of?" Tags="|sedimentology|limestone|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2878" PostTypeId="2" ParentId="2795" CreationDate="2014-11-22T09:28:57.090" Score="4" Body="&lt;p&gt;This is an important and pertinent question to help understand the 'late veneer' process on Earth.  To do so, understanding how it may have occurred, if at all, on the other terrestrial planets (Mercury, Venus, Mars and possibly the Moon, even possibly the rocky moons of other planets).  If there is no evidence, then that sheds light on another aspect of the uniqueness of Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For practical reasons, my answer will focus on Mars and Venus, as according to an article specific on the topic, &lt;a href=&quot;http://arxiv.org/pdf/1306.4325v1.pdf&quot; rel=&quot;nofollow&quot;&gt;Dynamical and collisional constraints on a stochastic&#xA;late veneer on the terrestrial planets&lt;/a&gt; (Raymond et al. 2013), that asserts that the late veneer was&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;an accretionary phase for Venus, Earth and Mars but an&#xA;  erosive phase for Mercury and the Moon.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There are obvious difficulties in fully answering this question; however, Raymond et al. assert that evidence exists of 'late veneer' like activity for not only the Earth, but for the Moon and Mars, from the article:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Evidence for the late veneer comes from the existence of highly-siderophile&#xA;  elements (HSEs) in the mantles of Earth, Mars and the Moon. Simply put,&#xA;  HSEs are “iron-loving” elements that tend to partition into metal and should&#xA;  thus be removed from a planet’s mantle during core formation. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Mantle samples are taken from Martian meteorites that have landed on the Earth and are detailed in the paper &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0016703711005813&quot; rel=&quot;nofollow&quot;&gt;Evolution of the martian mantle inferred from the $^{187}Re$–$^{187}Os$ isotope and highly siderophile element abundance systematics of shergottite meteorites&lt;/a&gt; (Brandon et al. 2012) who observe the observations made by Raymond et al. as&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The&#xA;  measured concentration of HSEs in the Martian mantle is similar to the&#xA;  Earth’s (Walker, 2009; Brandon et al., 2012).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Based on a conclusion made by Brandon et al. that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The relatively high HSE abundances in both planetary mantles likely cannot be accounted for by high pressure–temperature metal–silicate partitioning at the bases of magma oceans, as has been suggested for Earth. If the HSE were instead supplied by late accretion, this event must have occurred prior to the crystallization of the last martian magma ocean.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;According to Raymond et al. the situation for for Venus and Mercury, the late veneer is modeled to have possibly affected their retrograde motion, but the authors admit that this is is speculative.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the absence of sufficient samples from Mercury and Venus, it is modeling rather than sampling that the authors use to hypothesise the possible effect of the Late Veneer on them.  Given Venus' size, it is likely that it, alongside Earth were the 'primary targets' of the late veneer bombardment.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Additional references:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Walker, R. J. 2009. Highly siderophile elements in the Earth, Moon and&#xA;  Mars: Update and implications for planetary accretion and&#xA;  differentiation. Chemie der Erde / Geochemistry 69, 101–125.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Walker, R. J., M. F. Horan, C. K. Shearer, and J. J. Papike 2004. Low&#xA;  abundances of highly siderophile elements in the lunar mantle:&#xA;  evidence for prolonged late accretion. Earth and Planetary Science&#xA;  Letters 224, 399–413.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-11-22T09:28:57.090" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2879" PostTypeId="1" AcceptedAnswerId="2889" CreationDate="2014-11-22T09:43:56.153" Score="8" ViewCount="1428" Body="&lt;p&gt;After reading the question and answer &lt;a href=&quot;https://earthscience.stackexchange.com/questions/947/is-there-any-correlation-between-la-ni%C3%B1a-el-ni%C3%B1o-and-seismic-activity&quot;&gt;Is there any correlation between La Niña/El Niño and seismic activity?&lt;/a&gt;, I am wondering if there is any evidence (case studies) to suggest that longer term climatic dynamics (long term trends in seasonality, ambient temperature and pressure, such as ice ages, warm epochs) has any effect on plate tectonic dynamics (rate of plate movement, frequency of megathrust events, earthquake and volcanic eruption frequency and severity etc)?&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-05-05T01:15:18.733" Title="Does the climate have any effect on plate tectonics?" Tags="|geophysics|climate|plate-tectonics|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2880" PostTypeId="2" ParentId="2875" CreationDate="2014-11-22T10:01:17.073" Score="8" Body="&lt;p&gt;Magnetohydrodynamic experiments intended to create laboratory analogues for the Earth's magnetic field generally use molten sodium rather than nickel. You can read about the details of one such project, DRESDYN, &lt;a href=&quot;http://arxiv.org/abs/1201.5737&quot; rel=&quot;noreferrer&quot;&gt;in this arXiv preprint&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The central part of the envisioned precession dynamo experiment… will be a cylindrical vessel of approximately 2 m diameter and length, rotating with up to 10 Hz around its symmetry axis, and with up to 1 Hz around another axis whose angle to the first axis can be varied between 90° and 45°. The inner cylindrical shell (made of copper) is immersed into a larger cylindrical stainless container with conical end parts that can later also be used to house alternative inner shells, e.g. in the form of ellipsoids.&lt;/p&gt;&#xA;&lt;p&gt;The mechanical and safety demands for such a large scale sodium experiment&#xA;are tremendous. With a total mass of approximately 20 tons (including the sodium&#xA;in the conical end parts and the stainless steel walls) the sodium filled cylinder will have a moment of inertia of around 104 kg m&lt;sup&gt;2&lt;/sup&gt;. With a rotation rate of 10 Hz and a precession rate of 1 Hz, this amounts to a gyroscopic moment of 5 × 10&lt;sup&gt;6&lt;/sup&gt; Nm which requires an extremely massive basement and a careful avoidance of resonances. Further, the experiment must be fenced by a containment which can be quickly flooded with Argon in case of a sodium accident.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Exciting stuff! &lt;a href=&quot;https://www.hzdr.de/db/Cms?pNid=3163&quot; rel=&quot;noreferrer&quot;&gt;Here's the project website&lt;/a&gt;. According to a presentation at EGU this year, the building is currently under construction.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://complex.umd.edu/research/MHD_dynamos/MHD_dynamos.php&quot; rel=&quot;noreferrer&quot;&gt;A group at the University of Maryland&lt;/a&gt; is conducting similar research, and has already constructed some experimental sodium dynamos.&lt;/p&gt;&#xA;&lt;p&gt;I'm not aware of any such experiments involving nickel. Despite its high reactivity, sodium is easier to use for such experiments because of its much lower melting point and density. Nickel's melting point (1455°C) is only 83° below that of iron, so liquid nickel in an iron shell would be a tricky proposition.&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-11-22T15:17:27.120" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2881" PostTypeId="2" ParentId="2877" CreationDate="2014-11-22T13:25:57.503" Score="13" Body="&lt;p&gt;The building material comes from minerals dissolved in the ocean, mainly $\mathrm{Ca}^{2+}$, $\mathrm{Mg}^{2+}$, and &lt;a href=&quot;http://en.wikipedia.org/wiki/Bicarbonate&quot; rel=&quot;noreferrer&quot;&gt;$\mathrm{HCO}_3^{–}$&lt;/a&gt;, but of course there are all sorts of biochemical details. Most &lt;a href=&quot;http://en.wikipedia.org/wiki/Limestone&quot; rel=&quot;noreferrer&quot;&gt;limestone&lt;/a&gt; originated as the skeletons of micro- and macro-organisms, such as plankton and coral.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The minerals come in turn from the erosion of older rocks (&lt;a href=&quot;http://www.science20.com/news_releases/ocean_calcium_cycle_more_fragile_expected_and_climate_change_getting_blame&quot; rel=&quot;noreferrer&quot;&gt;among other places&lt;/a&gt;). For example, here are the famous white cliffs near Dover, UK, where massive amounts of calcium carbonate, mostly stable since the Cretaceous, &lt;a href=&quot;http://www.bbc.com/news/uk-17389616&quot; rel=&quot;noreferrer&quot;&gt;are falling into the sea&lt;/a&gt;, where it will be re-used:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/QU7qP.jpg&quot; alt=&quot;Cliffs at Dover by Harvey Barrison CC-BY-SA&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This attrition is part of the &lt;a href=&quot;http://en.wikipedia.org/wiki/Rock_cycle&quot; rel=&quot;noreferrer&quot;&gt;rock cycle&lt;/a&gt; and a very slow-moving part of the &lt;a href=&quot;http://en.wikipedia.org/wiki/Carbon_cycle&quot; rel=&quot;noreferrer&quot;&gt;carbon cycle&lt;/a&gt;. These are well-studied and reasonably well-understood.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You seem to suggest there is a paradox, that there's just constant deposition and no erosion or dissolution. But there is no paradox. The earth is not becoming thicker and thicker, material is not coming from space (not in substantial quantities anyway), and there's &lt;a href=&quot;http://en.wikipedia.org/wiki/Occam%27s_razor&quot; rel=&quot;noreferrer&quot;&gt;no need&lt;/a&gt; to invoke any processes we don't understand sufficiently to explain our large-scale observations. We know this because those processes would have a measurable effect on all sorts of things: the earth's orbit, climate, plate tectonics, and so on. There would be, I suggest, a strong low-frequency trend in all sorts of signals (stable isotopes, organism growth rates, sedimentation rates, volcanism rates, and so on). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The image is by &lt;a href=&quot;https://www.flickr.com/photos/hbarrison/4930390553&quot; rel=&quot;noreferrer&quot;&gt;Flickr/Harvey Barrison&lt;/a&gt;, CC-BY-SA.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2014-11-23T13:26:22.057" LastActivityDate="2014-11-23T13:26:22.057" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2882" PostTypeId="1" CreationDate="2014-11-22T16:05:12.087" Score="12" ViewCount="231" Body="&lt;p&gt;In recent years, I've heard weather reporters describe &quot;cut-off&quot; low pressure systems which park over Southern Ontario for days at a time. In summer months, they bring us long stretches of cool cloudy, often rainy days. In only the last couple of years, there was mention of the &quot;polar vortex&quot; which seemed to unusually extend and deepen our winter last year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't recall mention of either term in weather reports for the Southern Ontario region more than a few years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Over the meteorological record for this region, are these new patterns? If they are not new patterns, is it simply a trend in weather reporting to apply these terms?&lt;/p&gt;&#xA;" OwnerUserId="1210" LastEditorUserId="64" LastEditDate="2015-05-04T16:29:28.323" LastActivityDate="2015-05-05T12:44:27.370" Title="Are the &quot;polar vortex&quot; and &quot;cut-off lows&quot; over/near the Great Lakes new phenomena?" Tags="|meteorology|dynamics|synoptic|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2883" PostTypeId="1" CreationDate="2014-11-22T16:30:15.443" Score="9" ViewCount="969" Body="&lt;p&gt;I have seen &lt;a href=&quot;https://chrome.google.com/webstore/detail/the-ultimate-weather-app/hjdnakgakbbofjpdcogjocponodcgiai&quot; rel=&quot;noreferrer&quot;&gt;weather balloon measurements of air&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is this done?  Aren't the measurements we take on the ground enough?&lt;/p&gt;&#xA;" OwnerUserId="1078" LastEditorUserId="124" LastEditDate="2014-11-23T09:53:52.397" LastActivityDate="2014-11-24T23:44:32.160" Title="What is the reason why there are radiosonde measurements in the atmosphere?" Tags="|meteorology|radiosounding|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2884" PostTypeId="2" ParentId="2883" CreationDate="2014-11-22T18:47:00.090" Score="3" Body="&lt;p&gt;Forecasts that incorporate the 3-dimensional structure of the atmosphere are more accurate than those that only use the surface structure.&lt;/p&gt;&#xA;" OwnerUserId="30" LastActivityDate="2014-11-22T18:47:00.090" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2885" PostTypeId="2" ParentId="2883" CreationDate="2014-11-23T00:27:32.860" Score="4" Body="&lt;p&gt;The atmosphere is dynamic both horizontally and vertically.  You cannot provide services like weather forecasts without a true measurement of the atmospheric conditions in the troposphere and stratosphere across the globe.  Satellite retrievals also rely upon measured vertical profiles for calibration of the final products.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Radiosonde&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/Radiosonde&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Radiosondes are an essential source of meteorological data, and hundreds are launched all over the world daily. Worldwide there are more than 800 radiosonde launch sites. Most countries share data with the rest of the world through international agreements. Nearly all routine radiosonde launches occur 45 minutes before the official observation time of 0000 UTC and 1200 UTC, so as to provide an instantaneous snapshot of the atmosphere. This is especially important for numerical modeling. In the United States the National Weather Service is tasked with providing timely upper-air observations for use in weather forecasting, severe weather watches and warnings, and atmospheric research. The National Weather Service launches radiosondes from 92 stations in North America and the Pacific Islands twice daily. It also supports the operation of 10 radiosonde sites in the Caribbean.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastActivityDate="2014-11-23T00:27:32.860" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2886" PostTypeId="2" ParentId="2863" CreationDate="2014-11-23T01:46:44.863" Score="8" Body="&lt;p&gt;There are some well established means of detection of an imminent volcanic eruption; however, having said that, I must mention the caveat that not all the signs occur and in some cases, such as the recent &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2545/why-would-volcano-eruption-cause-cardiac-arrest&quot;&gt;Mt. Ontake&lt;/a&gt; eruption in Japan - volcanoes can erupt without warning.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another thing to consider is that the notion of a volcanic eruption anywhere on the Australian mainland is enough to get the media all excited and to latch on any piece of sensationalism, as suggested by one of the commenters in this &lt;a href=&quot;http://volcanism.wordpress.com/2011/07/05/prof-warns-of-volcanic-threat-to-south-east-australia-that-word-overdue-again/&quot; rel=&quot;nofollow noreferrer&quot;&gt;volcanism blog entry&lt;/a&gt;, stating in regards to quotes and information the media attribute to &lt;a href=&quot;http://earthsci.unimelb.edu.au/Joyce/joyce.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Professor Bernie Joyce of Melbourne University&lt;/a&gt; (A person I have met in the past and I can vouch for his non-alarmism):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This nonsense runs in the media here about once a year. What Dr Joyce is really trying to say is that Southwest Victoria has a history of monogenetic volcanism, and should have some contingency plans in place similar to Auckland.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, the signs of an impending volcanic eruption &lt;em&gt;may&lt;/em&gt; include the following (in summary from the Oregon State University page &lt;a href=&quot;http://volcano.oregonstate.edu/what-are-signs-volcano-about-erupt&quot; rel=&quot;nofollow noreferrer&quot;&gt;What are the signs that a volcano is about to erupt?&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First and foremost, increased or anomalous seismicity (as suggested by Gary Kindel in the comments to the question).  Earthquakes are not uncommon in Australia, and not uncommon in the area in the volcanic field of Victoria and South Australia.  Some earthquakes have been reasonably severe, as shown in the map below, from the University of Western Australia's webpage &lt;a href=&quot;http://www.seismicity.see.uwa.edu.au/welcome/seismicity_in_australia/volcanoes_and_earthquakes_in_southeastern_australia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Volcanoes &amp;amp; Earthquakes in SE Australia&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/0QMlX.gif&quot; alt=&quot;enter image description here&quot;&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The red triangles are a handful of the more 'significant' of the 300+ volcanoes in the region.  The purple represent earthquakes with magnitudes greater than 4.0 on the Richter Scale and the blue are all earthquakes recorded between 1995-2004.  A word of caution with this map, it has been only since the 1960's that earthquakes have been recorded.  The largest earthquake in the region was 6.5 on the Richter Scale in 1897 (north-west of Mt. Gambier).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, as earthquakes in Australia are intraplate, they tend to be considerably shallower than those from plate margins, with, according to the &lt;a href=&quot;http://www.src.com.au/earthquakes/seismology-101/earthquakes-in-australia/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seismology Research Centre&lt;/a&gt;, depths usually less than 20km. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the USGS &lt;a href=&quot;http://earthquaketrack.com/au-05-mount-gambier/recent&quot; rel=&quot;nofollow noreferrer&quot;&gt;earthquake track page for Mt. Gambier&lt;/a&gt;, there has been some seismic activity in the past 25 years, but not much at all - a total of 5 earthquakes, ranging in magnitude from 2.8 to 4.7 and at depths from 10-22km - not particularly anomalous, especially when compared by the literally &lt;a href=&quot;http://www.src.com.au/earthquakes/&quot; rel=&quot;nofollow noreferrer&quot;&gt;dozens of quakes&lt;/a&gt; occurring in the state of Victoria (including non-volcanic areas) of similar magnitude and depths in 2014 alone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, as more seismographs have been established over the area, there have been some anomalies, including (from the University of Western Australia):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Three earthquakes of magnitude approximately 2.5 occurred in the vicinity of Mount Gambier in January and February of 2003, with greater than usual depths ( ie, approximately 40 km deep). Some scientists have suggested that they may be generically related to the volcanoes in the area.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;According to the Geoscience Australia report &lt;a href=&quot;http://www.aees.org.au/wp-content/uploads/2013/11/McCue_ASR2008.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Australian Seismological&#xA;Report 2008 - addendum&lt;/a&gt;, there is still significant seismic activity around Mt. Gambier and comparatively less in western Victoria (as seen in the map above).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Oregon State University document also states that the presence of fumaroles and ground deformation are also signs of &lt;em&gt;potential&lt;/em&gt; volcanic activity.  In terms of western Victoria and south-east South Australia, a conclusion regarding this is given by the University of Western Australia:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Many of the volcanoes have preserved their classical volcanic shapes, and the region is considered by some to be volcanically dormant rather than extinct. However, note the conclusion by Cliff Ollier ( in &quot;Landform Studies from Australia &amp;amp; New Guinea, by Jennings &amp;amp; Mabbutt, 1967, p 338) - &quot; Perhaps the most remarkable feature of Victorian vulcanicity is its complete cessation. Older basalts were erupted in Victoria through long periods in the Tertiary: the newer basalts were erupted throughout the Pleistocene and extended into the Recent. The last eruption probably took place only 5000 years ago, and yet there are no fumaroles, no hot springs, no anomalous temperature gradients or seismic effects, in fact nothing to indicate how recently the volcanic activity ceased.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, according to the Romsey Australia blog-page &lt;a href=&quot;http://home.iprimus.com.au/foo7/volcmap.html#2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Is there a risk of a volcanic eruption in Australia?&lt;/a&gt;, Professor Bernie Joyce has developed a volcanic hazard map, regarding the potential risk according to his research and observations:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/41i1T.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And notes that with an eruption that formed Mt. Gambier &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;an eruption could either be an explosion like the one at Mt Gambier, creating a big hole in the ground&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;with little or no warning.  But another scientist Dr. Wally Johnson disagrees in part, stating:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;If Mt Gambier did erupt it would impact on local communities,&quot; Johnson said. &quot;But any changes to the state of these volcanoes would be noticed early on, either through earthquakes, or in the case of Mt Gambier an increase in the temperature of the water.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This leads to one final point, recent studies and observation reported in the Romsey blog section &lt;a href=&quot;http://home.iprimus.com.au/foo7/volcmap.html#6&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geologists suspect an earthquake that originated 50 kilometres from King Island in February 2002 signalled the reawakening of the hot spot&lt;/a&gt; - Bass Strait is the waterway separating Victoria and Tasmania - this is known as the &lt;a href=&quot;http://www.nature.com/nature/journal/v454/n7205/fig_tab/nature07138_F2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;East Australian Hotspot&lt;/a&gt; which is a considerable distance from Mt Gambier and the other Victorian/South Australian volcanic centres.  Shown on the map below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/JkNv9.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/nature/journal/v454/n7205/fig_tab/nature07138_F2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image Source&lt;/a&gt;: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Rapid change in drift of the Australian plate records collision with Ontong Java plateau&#xA;  Kurt M. Knesel, Benjamin E. Cohen, Paulo M. Vasconcelos &amp;amp; David S. Thiede&#xA;  Nature 454, 754-757(7 August 2008)&#xA;  doi:10.1038/nature07138&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-11-23T01:46:44.863" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2887" PostTypeId="2" ParentId="2879" CreationDate="2014-11-23T05:46:23.660" Score="6" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Isostatic_depression&quot; rel=&quot;nofollow&quot;&gt;Isostatic depression&lt;/a&gt; and &lt;a href=&quot;http://en.wikipedia.org/wiki/Post-glacial_rebound&quot; rel=&quot;nofollow&quot;&gt;Post-glacial rebound&lt;/a&gt; are something that we can definitely observe, are definitely caused by climate changes, and pretty clearly count as an &quot;effect on plate tectonics&quot;, since they change the vertical profile of the plates and thus must have an effect on how they move.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I would say the answer is &quot;yes&quot;.&lt;/p&gt;&#xA;" OwnerUserId="1153" LastEditorUserId="1153" LastEditDate="2014-11-24T09:09:22.637" LastActivityDate="2014-11-24T09:09:22.637" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2888" PostTypeId="1" CreationDate="2014-11-23T09:47:05.907" Score="8" ViewCount="307" Body="&lt;p&gt;The Igwisi Hills Kimberlite volcanic features in Tanzania are described in the article &lt;a href=&quot;http://gef.nerc.ac.uk/documents/reports/894.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mapping the Igwisi Hills kimberlite volcanoes, Tanzania: understanding &#xA;how deep-sourced mantle magmas behave at the Earth`s surface&lt;/a&gt; (Brown and Sparks), as being Quaternary or younger in age and consistent with my earlier question and answer, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2509/what-is-it-about-ancient-craton-geology-that-results-in-associated-kimberlite-pi&quot;&gt;What is it about ancient craton geology that results in associated kimberlite pipes containing economic diamond deposits?&lt;/a&gt;, it had erupted through the &lt;a href=&quot;http://en.wikipedia.org/wiki/Tanzania_Craton&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tanzania Craton&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The article &lt;a href=&quot;http://www.srk.com/files/File/papers/Jelsma-Barnett-Richards-Lister-2009-Lithos-Tectonic-setting-kimberlites.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tectonic setting of kimberlites&lt;/a&gt; (Jelsma et al. 2009) has made correlations between older kimberlite volcanics and aspects of the supercontinent cycle, specifically:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Kimberlites can be viewed as time capsules in a global plate tectonic framework. Their distribution illustrates&#xA;  clustering in time and space. Kimberlite ages span the assembly and break-up of a number of&#xA;  supercontinents, such as Rodinia and Gondwana. These supercontinents show time lines with (i) broad&#xA;  periods devoid of kimberlite magmatism corresponding to times of continent stability, and (ii) narrow&#xA;  kimberlite emplacement windows corresponding to times of fundamental plate reorganizations.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Implying a link between parts of the supercontinent cycle and kimberlite magmatism.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this implied tectonic setting does not seem to match with Quaternary Tanzania, when the Igwisi Hills kimberlite volcanoes erupted.  &lt;strong&gt;Therefore, what are the tectonic implications of the Quaternary Igwisi Hills, Tanzania, kimberlite volcanics?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only thing that comes to mind is the East African Rift tectonics, but are not sure about this link.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-11-27T18:34:19.003" Title="What are the tectonic implications of the Quaternary Igwisi Hills, Tanzania, kimberlite volcanics?" Tags="|volcanology|plate-tectonics|economic-geology|east-africa-rift|kimberlite|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2889" PostTypeId="2" ParentId="2879" CreationDate="2014-11-23T14:20:09.120" Score="9" Body="&lt;p&gt;According to the article &lt;a href=&quot;http://www.nature.com/nature/journal/v425/n6960/full/nature02049.html&quot; rel=&quot;noreferrer&quot;&gt;Cenozoic climate change as a possible cause for the rise of the Andes&lt;/a&gt;, the climate could affect mountain building by altering the amount of erosion, and therefore sediment deposits, which could act as a lubricant in subduction zones. In the example given, the lack of sediment increased friction, causing &quot;crumpling&quot; and the building of the Andes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given that the climate impacts erosion, that erosion may then affect the stress loading of thrust faults, affecting the earthquake frequency and magnitude, the same as post-glacial rebound.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Isostatic rebound resulting from melting glaciers may also impact volcanics, by changing the pressures, and so lowering the melting point if the rocks. &quot;The average melting rate is increased by about 30 times its steady state value when a 2-km-thick ice sheet melts in 1000 years.&quot; In Iceland, the melting of the glaciers at the end of the last ice age correlates with a 30-fold increase in eruption rate. (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/96JB01308/abstract;jsessionid=6FA52E592A61EBC2AB721CE97713A4A5.f02t01&quot; rel=&quot;noreferrer&quot;&gt;Source&lt;/a&gt;)in &lt;/p&gt;&#xA;" OwnerUserId="1211" LastEditorDisplayName="user889" LastEditDate="2014-12-10T04:49:34.273" LastActivityDate="2014-12-10T04:49:34.273" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2890" PostTypeId="1" AcceptedAnswerId="2894" CreationDate="2014-11-23T23:25:43.203" Score="8" ViewCount="734" Body="&lt;p&gt;After wondering on the validity of &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2840/is-the-principle-of-original-horizontality-a-good-indicator/&quot;&gt;the principle of Original Horizontality&lt;/a&gt;, I'm now focusing on the principle of fossil succession.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This principle states that :&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Fossils of species that did not coexist in the same geological period were found to be in different strata. The principle provided a way for geologists to determine the age of a particular rock layer based on the fossils embedded in it. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This principle seems illogical to me. Let's say that in South America, fossils of a certain species are found, and dated to be from Jurassic. Now, same fossils are found in Europe, and therefore we should conclude that stratum are from Jurassic too. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As we know that Earth is all the time disrupts by inner motions of its cores, what if those motions implied a fossil to move over stratum? It would imply a miscalculation here. How can I prove that this principle is safe?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(For better understanding, imagine that I bury a box at a certain place. If you come 2 years later, nothing proves that you'll be able to find it again, because 'things move in the inside')&lt;/p&gt;&#xA;" OwnerUserId="1138" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-11-24T13:20:03.170" Title="Is the Principle of Fossil Succession accurate?" Tags="|paleontology|fossils|stratigraphy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2892" PostTypeId="2" ParentId="2883" CreationDate="2014-11-23T23:41:22.547" Score="7" Body="&lt;p&gt;The reason is that we need them!  And we could probably do with more of them (e.g. bigger launch budgets).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Surface observations will tell us where fronts are, where low and high pressure is, and how surface temperature and moisture are being advected.  We can also deduce large scale ascent or descent (vertical motion) from surface divergence and convergence.  We might even be able to provide very short term forecasting, though the skill won't be great. To know how the surface will evolve you need to know what is going on above the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we know what the 500 mb surface looks like, we can combined this information with the surface fields and some quasi-geostrophic theory and do better with short term forecasts.  With just one upper air layer we can see how the feedbacks between the mid/upper-troposphere and the surface will behave and better predict the development and motion of low pressure systems.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To provide more accurate forecasts, have a shot at predicting convection, and provide longer term forecasts we need more information about the vertical structure of the atmosphere.  The current state of models are such that one of the best things we can do to improve them are to provide better initial conditions (better observations and more of them).  Balloon launches are a great way of getting this data.  Ground and satellite based observations can provide parts of this, but we still benefit from being able to directly sample the atmosphere and to calibrate the remote sensing algorithms with the radiosondes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One example of the necessity of balloon launches is in convection.  Knowing only surface convergence, temperature and moisture is important, but does not tell the whole story.  If the 850 mb temperatures are too warm, it won't matter how good the surface observations look, you won't get convection.  How much energy the storm can tap into depends on the temperatures all the way up to the tropopause (and higher if you want to know how high the cloud tops will be).  Knowing what type of storm to expect depends on knowing the winds in at least the bottom 6 km of the atmosphere.  Having vertical information provided by a radiosonde is the difference in only being able to say &quot;the air is warm and juicy&quot; versus being able to say &quot;expect isolated supercells today with large hail and straight-line wind damage&quot; or &quot;despite the high dew points, the capping inversion and associated CIN will suppress all convection today -- no storms&quot; given the exact same surface observations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And yes, models can give us the upper air structure to base these kind of statements on, but remember the radiosonde launches are where a lot of the upper-air data comes from that allows the models to work well comes from.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2014-11-24T23:44:32.160" LastActivityDate="2014-11-24T23:44:32.160" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2893" PostTypeId="1" CreationDate="2014-11-24T02:43:39.823" Score="14" ViewCount="509" Body="&lt;p&gt;Is there a connection between the colors of oceanic waters near the coast and Ekman pumping? Along the coastal areas of the Bay of Bengal where I live, occasionally during the monsoon, the colors of the waters become aquamarine, only to become sky blue in color a few hours later as the sea breeze sets in. &#xA;Can this be explained by coastal upwelling?  If this is due to Ekman pumping where does EP take place? Over equatorial waters and is then pushed north due to a coastal current? &#xA;The phenomenon has been observed during both the Indian monsoons- the south west monsoon as well as the north east monsoon i.e. that the seasonal shift in wind direction does not impact the appearance of the aquamarine color. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The width of the patch is between 200-300 meters from the coast and it is oriented parallel to the coast. Closer to the coast the color is dark greenish brown and as you go further into the open sea it is aquamarine green. There are occasional dark blue &quot;patches&quot;(dark blue bands) which I am presuming is phytoplankton. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Few more personal observations. It appears that the aquamarine color usually manifests itself during the mornings (when there is no breeze whatsoever). The sea presents extremely gentle waves when the aquamarine color is visible. Does that mean that the origin of the aquamarine color is &quot;non - local&quot; ? &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2015-01-01T09:46:07.190" LastActivityDate="2015-01-01T09:46:07.190" Title="Color of ocean waters and Ekman pumping - what is the connection?" Tags="|ocean|oceanography|climatology|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2894" PostTypeId="2" ParentId="2890" CreationDate="2014-11-24T08:53:36.370" Score="9" Body="&lt;p&gt;Your analogy with burying a box is not as accurate as you think. It needs specific sedimentary conditions for the remains of an organism to fossilize: being buried in soil is far from enough.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fossilization is such that, eventually, the fossil will be embedded in its stratum, meaning that tectonic events (as you suggest) that would displace the fossil will also displace the stratum around it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However you are right to question the principle of succession in the sense that, things can happen before the fossil is embedded in its stratum. Namely you have three common phenomena: reworking, downworking, and time averaging.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Reworking&lt;/strong&gt;, the more common phenomenon. It can occur when the sediment that originally contain the fossil is being eroded. What the sediment contained is therefore once again put in the system and need to be either dissolved or re-sedimented in a new stratum.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Downworking&lt;/strong&gt; is (I think) more frequent in marine settings: before the sediment is consolidated, the fossil sinks into it, into an as-well unconsolidated but older sediment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Time averaging.&lt;/strong&gt; It can take a lot of time for a sediment to consolidate into a stratum, time during which organism remains continue to rain on the sediment. The stratum will therefore not represent a point in time but a time-span corresponding to the time it took to the sediment to consolidate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of the three phenomena, only reworking is really problematic (the two other being only moderate time displacement, rarely more than a couple of $10^5$ years). However it is usually manageable to recognize the fact that a fossil was reworked (different alteration compared to other fossils in the same stratum for instance, and if the sediment was already consolidated when the fossil was displaced you will find bits of the old sediment still attached to it). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is also another problem (regarding your example of a Jurassic species deposited in South America and the same species deposited in Europe), which is biogeography: a species does not appear and disappear at the same time everywhere on Earth (see illustration below). In most cases the time discrepancy is small but in some case it isn't: this is what we call, in biostratigraphy, &lt;em&gt;diachronism&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Uzpsj.png&quot; alt=&quot;Illustration of the problem of diachronism&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Taken from Peter Sadler's &lt;a href=&quot;http://www.paleosoc.org/shortcourse2010/extended-CONOP-COURSE-NOTES.pdf&quot; rel=&quot;noreferrer&quot;&gt;short course&lt;/a&gt; on biochronology. The grey area represent the taxon extent in time and space.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="28050" LastEditDate="2014-11-24T13:20:03.170" LastActivityDate="2014-11-24T13:20:03.170" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2895" PostTypeId="1" CreationDate="2014-11-24T09:29:50.377" Score="6" ViewCount="546" Body="&lt;p&gt;The Cameroon Line is described by the Oregon State University's Volcano World webpage &lt;a href=&quot;http://volcano.oregonstate.edu/what-known-about-volcanoes-cameroon&quot; rel=&quot;nofollow noreferrer&quot;&gt;What is known about the volcanoes of Cameroon?&lt;/a&gt; as a &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;a chain of volcanoes extending from Annobon Island in the Atlantic Ocean northeastward through Cameroon. The oldest rocks have been dated at 70 million years old.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As in this map from the Global Volcanism Program's &lt;a href=&quot;http://www.volcano.si.edu/volcano.cfm?vn=224030&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oku Volcanic Field&lt;/a&gt; webpage:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/WJJ9E.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A notable active volcano in the area is &lt;a href=&quot;http://www.geo.arizona.edu/geo5xx/geos577/projects/kayzar/html/lake_nyos_disaster.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Nyos&lt;/a&gt; which killed 1700 people in an eruption that spewed noxious gases (mainly $\ce{CO2}$) in 1986.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The explanation for the active volcanism is given by Oregon State as being due to&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;About 80 million years ago, during a reorganization of plate boundaries, the African plate rotated counter-clockwise. Then a new rift formed that failed to split Africa but apparently did form conduits that allowed magma to ultimately reach the surface and form the volcanoes of the Cameroon line.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is there any evidence to suggest that the Cameroon Line is still a tectonically active rift system?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="725" LastEditDate="2014-12-20T08:33:43.327" LastActivityDate="2014-12-20T08:33:43.327" Title="Is the Cameroon Line still an active rift zone?" Tags="|geophysics|volcanology|plate-tectonics|continental-rifting|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2896" PostTypeId="2" ParentId="2879" CreationDate="2014-11-24T23:53:29.137" Score="4" Body="&lt;p&gt;I would argue that the heaviest impact on plate tectonics is not only climate, but the atmosphere and oceans as whole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oxygenation from the atmosphere and hydratation from the oceans will lead to a decrease in viscosity of minerals that are subducted with them. This can make sense if you think about it: $H_2 O$ and $O_2$ would be volatiles under lithospheric pressures and temperatures, however by subduction they are forced into the minerals' crystal lattice and can act as &lt;em&gt;mobile defects&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, lattice chemistry plays a role in defining the macroscopic material variables as viscosity, thermal conductivity and diffusivity of the melt. If my interpretation of the &lt;a href=&quot;http://en.wikipedia.org/wiki/Supercontinent_cycle&quot; rel=&quot;nofollow&quot;&gt;possibly-existing supercontinent-cycle&lt;/a&gt; is correct, this would mean that a significant portion of mantle-material 'sees' the surface every ~300-500Myears and then has the potential to be altered by surface/ocean chemistry for the next subduction cycle.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Update:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I had a quick discussion with a Geophysics Prof about this. He didn't know out from his head any good source for the viscosity due to $O_2$/$H_2O$ in minerals. However he has pointed me to &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0019103511003435&quot; rel=&quot;nofollow&quot;&gt;this article&lt;/a&gt; discussing a much stronger effect on Venusian plate tectonics: Surface temperatures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The paper argues that as viscosity goes like $\sim exp(E_{activation}/k_B T)$, a varying surface temperature from 750 to 1000K this can have quite an impact on the viscosity or the Peclet number (energy transport by convection over diffusion). The latter can vary in this range from &amp;lt;1 to &gt;100.&lt;br&gt;&#xA;But as the surface temperature obviously only poses a boundary condition, we don't know for sure how far down into the mantle those differences can propagate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Coming back to Earth it's obvious that this effect would obviously be much smaller, as surface Temperature variations won't be 250K over Gyr timescales. However interesting to note.&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="489" LastEditDate="2014-12-11T16:02:04.247" LastActivityDate="2014-12-11T16:02:04.247" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2897" PostTypeId="1" AcceptedAnswerId="3017" CreationDate="2014-11-25T08:35:39.473" Score="10" ViewCount="269" Body="&lt;p&gt;The Silurian Period is now known to have undergone several significant positive $\delta^{13}C_{carb}$ excursions, namely the early Aeronian, Late Aeronian, Valgu, Ireviken, Mulde, Lau &amp;amp; Klonk events (see e. g. &lt;strong&gt;Cramer et al. 2011; Gradstein et al. 2012&lt;/strong&gt;). It seems to me that those excursions where mainly studied in the context of chemostratigraphy and not paleoclimatology, though.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any hypotheses on what could have triggered these excursions?&lt;br&gt;&#xA;How come the short (ca. 24 Myr) Silurian be so unstable has to have so many significant excursions?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Sources:&lt;br&gt;&#xA;Cramer, &lt;em&gt;et al.&lt;/em&gt; 2011. &lt;a href=&quot;http://dx.doi.org/10.1111/j.1502-3931.2010.00234.x&quot;&gt;Revised correlation of Silurian Provincial Series of North America with global and regional chronostratigraphic units and $\delta^{13}C_{carb}$ chemostratigraphy.&lt;/a&gt; Lethaia, 44: 185-202.&lt;br&gt;&#xA;Gradstein, Ogg, Schmidt &amp;amp; Ogg (Eds). 2012. &lt;a href=&quot;http://www.sciencedirect.com/science/book/9780444594259&quot;&gt;The geologic time scale.&lt;/a&gt; Elsevier, Amsterdam: 1144pp.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastActivityDate="2014-12-11T13:27:55.550" Title="Hypotheses about Silurian carbon isotope excursions?" Tags="|paleoclimatology|carbon-cycle|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2898" PostTypeId="1" AcceptedAnswerId="2902" CreationDate="2014-11-25T09:52:11.620" Score="10" ViewCount="470" Body="&lt;p&gt;According to the University of California Museum of Palaontology webpage &lt;a href=&quot;http://www.ucmp.berkeley.edu/ordovician/ordovician.php&quot;&gt;The Ordovician Period&lt;/a&gt;, the late Ordovician period witnessed&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;when Gondwana finally settled on the South Pole during the Upper Ordovician, massive glaciers formed, causing shallow seas to drain and sea levels to drop. This likely caused the mass extinctions that characterize the end of the Ordovician in which 60% of all marine invertebrate genera and 25% of all families went extinct.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;NASA's webpage &lt;a href=&quot;http://www.nasa.gov/vision/universe/starsgalaxies/gammaray_extinction.html&quot;&gt;Explosions in Space May Have Initiated Ancient Extinction on Earth&lt;/a&gt; and the paper &lt;a href=&quot;http://cds.cern.ch/record/642831/files/0309415.pdf&quot;&gt;Did a gamma-ray burst initiate the late &#xA;Ordovician mass extinction? &lt;/a&gt; suggest that a gamma ray burst may have initiated the cooling at approximately 440 million years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What palaeoclimatological and geochemical evidence is there to support or refute the gamma ray burst cause of the late Ordovician mass extinction?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-11-25T14:54:56.830" Title="Did a gamma ray burst contribute to the Ordovician mass extinction?" Tags="|paleoclimatology|mass-extinction|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2899" PostTypeId="2" ParentId="2898" CreationDate="2014-11-25T12:56:00.963" Score="5" Body="&lt;p&gt;The answer that you're asking is within the paper that you cited in the question:&lt;br/&gt;&#xA;&lt;a href=&quot;http://cds.cern.ch/record/642831/files/0309415.pdf&quot;&gt;Did a gamma-ray burst initiate the late&#xA;Ordovician mass extinction?&lt;/a&gt; (Melot et al).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Specifically the section titled &quot;ASPECTS OF THE LATE ORDOVICIAN MASS EXTINCTION POTENTIALLY&#xA;COMPATIBLE WITH A GRB&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But if you're looking for an article summary, here is the evidence they mention that may point to a Gamma Ray Burst (GRB) as a possible source of the extinction:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Rapid global cooling followed by rapid global warming&lt;/strong&gt;&lt;br/&gt;&#xA;Specifically, they say that a GRB may cause the production of NO&lt;sub&gt;2&lt;/sub&gt;, which will increase the opaqueness of the atmosphere, causing cooling.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Some species impacted more than others&lt;/strong&gt;&lt;br/&gt;&#xA;They mention that this &lt;em&gt;may&lt;/em&gt; have happened, but that they would expect:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;planktonic organisms or larvae would more likely be&#xA;  affected than benthic organisms because the former are less shielded from radiation. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Similarly, epifaunal organisms would be more&#xA;  affected than infaunal organisms buried and shielded in sediments. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They go on to say that both of these patterns &quot;may exist&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Differential extinction&lt;/strong&gt;&lt;br/&gt;&#xA;They probably say this best:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;longer planktonic&#xA;  larval phases, when such can be inferred, are associated with increased extinction probability&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The mention that species whose adults live within plankton were completely wiped out.  This differential extinction is somewhat suggestive of a GRB.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Summary&lt;/strong&gt;&lt;br/&gt;&#xA;Ultimately,  there's not a clear and definitive link to a Gamma Ray Burst as the sole or primary source of this extinction event.  However, there are some correlations.  In the author's words, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;clearly additional tests are required&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;source: &lt;a href=&quot;http://cds.cern.ch/record/642831/files/0309415.pdf&quot;&gt;Did a gamma-ray burst initiate the late&#xA;Ordovician mass extinction?&lt;/a&gt; (Melot et al).&lt;/p&gt;&#xA;" OwnerUserId="330" LastActivityDate="2014-11-25T12:56:00.963" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2900" PostTypeId="1" CreationDate="2014-11-25T12:57:38.577" Score="8" ViewCount="413" Body="&lt;p&gt;I'm having some difficulty finding a WMS (web mapping server) for North America GOES-East satellite imagery that matches my needs (visible and IR4, timely, with no alteration of grey-scale pixel values).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have tried the Iowa State and Nowcoast servers, but, for various reasons, the data isn't exactly what I need. I would like to experiment with other WMS servers, but I can't find any. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do you know of any alternative WMS servers for GOES-East satellite imagery, other than Iowa State and Nowcoast?&lt;/p&gt;&#xA;" OwnerUserId="669" LastEditorUserId="669" LastEditDate="2014-11-25T14:55:15.797" LastActivityDate="2020-12-25T17:07:10.723" Title="Alternative WMS servers for GOES-East satellite imagery" Tags="|weather-satellites|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2901" PostTypeId="1" AcceptedAnswerId="2903" CreationDate="2014-11-25T13:34:17.197" Score="18" ViewCount="17035" Body="&lt;p&gt;I was reading about kimberlite on Wikipedia and it mentioned eluvium. I've heard of alluvium, alluvial fans, alluvial deposits, etc. However, when I looked up eluvium, it sounded exactly like alluvium.&lt;/p&gt;&#xA;&lt;p&gt;Indeed, looking at the Wikipedia articles, the definitions sound identical to my (expertly untrained) ears:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Alluvium:&lt;/strong&gt; loose, unconsolidated (not cemented together into&#xA;a solid rock) soil or sediments, which has been eroded, reshaped&#xA;by water in some form, and redeposited in a non-marine setting.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Eluvium:&lt;/strong&gt; geological deposits and soils that are derived by in&#xA;situ weathering or weathering plus gravitational movement or&#xA;accumulation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So, both of these sound like soil and sediments, eroded and deposited. But obviously, they can't be the same thing.&lt;/p&gt;&#xA;&lt;p&gt;What's the difference? How can I tell the difference if I see it &amp;quot;in the wild&amp;quot;?&lt;/p&gt;&#xA;" OwnerUserId="330" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-09-08T00:02:34.147" Title="What is the difference between eluvium and alluvium?" Tags="|geology|sedimentology|terminology|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2902" PostTypeId="2" ParentId="2898" CreationDate="2014-11-25T14:15:42.250" Score="8" Body="&lt;p&gt;As a preamble, let me say that I don't know remotely enough on galactic dynamic to know if a supernova could have possibly been close enough during the Ordovician for Earth to be affected by a gamma ray burst, nor do I know enough about geochemistry to know if there are ways to detect such an event in the fossil record.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That being said, the questions that I'll try to answer are: do we need to invoke an extraterrestrial event to explain the Late Ordovician glaciation? does the taxa selectivity of the extinction event support the GRB hypothesis?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So let's look at the different hypotheses on how the glaciation occurred, the original conundrum being: how could a glaciation occur when mid-Ordovician $p_{CO_2}$ is &lt;em&gt;believed&lt;/em&gt; to be up to 14 times Quaternary level? &lt;strong&gt;Brenchley et al. 1994&lt;/strong&gt; suggested that the Ordovician ocean circulation changed from a system having warm saline bottom waters to a system with cold bottom waters (i. e. a thermohaline instead of an haline circulation), which triggered a phytoplanktonic bloom, which then decreased atmospheric $p_{CO_2}$ and provoked an eutrophization of the ocean. &lt;strong&gt;Kump et al. 1999&lt;/strong&gt; argued in favor of a tectonically derived $p_{CO_2}$ decline: with the Appalachian and Caledonides orogenesis came an increased weathering which decreased $p_{CO_2}$. Of course the two hypotheses are not mutually exclusive since increased weathering also means increasing nutrients in seawater and therefore increasing primary productivity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another question is which groups went extinct during the glaciation: recent studies show that acritarchs (the most diverse group of phytoplankton known for that period) did not suffer from these events (&lt;strong&gt;Vecoli 2008&lt;/strong&gt;); oppositely benthic group such as crinoids or brachiopods did (see &lt;strong&gt;Sheehan 2001&lt;/strong&gt; for a review); some pelagics groups such as graptolites and nautiloids did suffer as well during the event while some other didn't (radiolarians for instance). In summary there is no clear pattern, but there is also no reason to think that there was a preferential extinction of surface organisms over deeper-living ones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, does that answer the question: no; but it seems to me that GRB doesn't explain better the event that unfolded during the late Ordovician than other hypotheses (namely the ocean eutrophization and the continental weathering). Does it discard the hypothesis of a GRB: no; but since there is no direct evidence that it indeed happened at that time, and that we can explain the Ordovician events without, it seems, to me, more parsimonious to think that it didn't.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;References:&lt;br&gt;&#xA;Brenchley et al., 1994. &lt;a href=&quot;http://geology.gsapubs.org/content/22/4/295.short&quot;&gt;Bathymetric and isotopic evidence for a short-lived Late Ordovician glaciation in a greenhouse period.&lt;/a&gt; Geology, 22: 292-298.&lt;br&gt;&#xA;Kump et al., 1999. &lt;a href=&quot;http://dx.doi.org/10.1016/S0031-0182(99)00046-2&quot;&gt;A weathering hypothesis for glaciation at high atmospheric $p_{CO_2}$ during the Late Ordovician&lt;/a&gt;. Palaeogeography, Palaeoclimatology, Palaeoecology, 152: 173-187.&lt;br&gt;&#xA;Sheehan, 2001. &lt;a href=&quot;http://usuarios.geofisica.unam.mx/cecilia/CT-ST/Sheehan2001OrdovicianExtintion.pdf&quot;&gt;The Late Ordovician Mass Extinction.&lt;/a&gt; Annual review of Earth and Planetary Science, 29: 331-364.&lt;br&gt;&#xA;Vecoli, 2008. &lt;a href=&quot;http://dx.doi.org/10.1016/j.revpalbo.2006.11.004&quot;&gt;Fossil microphytoplankton dynamics across the Ordovician–Silurian boundary&lt;/a&gt;. Review of Paleobotany and Palynology, 148: 91-107.&#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-11-25T14:54:56.830" LastActivityDate="2014-11-25T14:54:56.830" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2903" PostTypeId="2" ParentId="2901" CreationDate="2014-11-25T19:35:30.350" Score="15" Body="&lt;p&gt;Both are very similar, as they are based on minerals undergoing erosion and the presence of water in the erosion and deposition cycles, the difference is quite subtle, an example is defined in the Gold Prospecting in Western Australia website &lt;a href=&quot;http://www.gold-prospecting-wa.com/alluvial-gold.html&quot;&gt;Alluvial Gold and Eluvial Gold&lt;/a&gt; as being&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Alluvial&lt;/strong&gt; deposits are mixed with other deposits and are washed downstream in rivers or transported in among other sediments with water as its medium. An example is that gold deposits this way are smoothed and are ground down the further from the source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Eluvium&lt;/strong&gt; deposits are &lt;em&gt;in situ&lt;/em&gt; or very near its source, rather than been washed away by water.  For example, eluvial gold are often large nuggets nearer to its source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A much more succinct definition is provided by &lt;a href=&quot;http://australianmuseum.net.au/Geological-ore-deposits/&quot;&gt;the Australian Museum&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Alluvium&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Detrital material which is transported by a river and usually deposited along the river's pathway, either in the riverbed itself or on its floodplain.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Eluvial&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Weathered material still at or near its point of formation. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-11-25T19:35:30.350" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2904" PostTypeId="2" ParentId="2302" CreationDate="2014-11-25T22:42:14.620" Score="8" Body="&lt;p&gt;This is a bit of a what-if kind of answer, with some rough estimates. Just considering the cooling aspect - let's pretend that Earth is solid for a momnet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The time-dependent heat equation tells us how long it will take for a change in temperature to travel a certain distance by conduction (the 'characteristic timescale'). The distance to the outer core, where the magnetic field is generated, is about 3000 km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assume that the geothermal installation is at the surface, and that it loses its heat instantaneously. Then, the 'characteristic timescale' is given by &#xA;$$&#xA;\tau = \frac{l^2}{\kappa}&#xA;$$&#xA;Taking $ l=3 \times 10^{6} $m as the distance to travel, and $ \kappa = 1 \times 10^{-6}  $m&lt;sup&gt;2&lt;/sup&gt;/s as the mean thermal diffusivity of the rocks, then it would take $ 2.85 \times 10^{11} $ years for the change in temperature due to extracting geothermal heat at Earth's surface to propagate to the outer core. The sun would have transitioned to a red giant by then.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem being of course that it's not all solid. Convection in the mantle would obliterate the temperature signal. I don't know how you'd go about calculating that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More practically, a deep geothermal project of the EGS flavour would be managed as a mining project. The reservoir would be used up within 20 years or so, then either abandoned or mothballed (until perhaps it reheated?). The maximum temperature drawdown for economic feasibility might be of the order of 50°C or less, depending on a boatload of factors. &lt;/p&gt;&#xA;" OwnerUserId="61" LastActivityDate="2014-11-25T22:42:14.620" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2905" PostTypeId="1" CreationDate="2014-11-26T03:57:34.567" Score="3" ViewCount="768" Body="&lt;p&gt;Magnetic measurements have been made on some lavas found at 60ºN and 90ºW. The inclination angle is 37º. If the horizontal direction of magnetism of these lavas is due west, calculate the position of earth's magnetic pole when these lavas errupted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found the magnetic latitude using $\arctan(\frac{1}{2}\tan(37^{\circ})) = 20.6^{\circ}$, but I'm not sure how to get the pole location since we are not given declination angle. I think you use this formula:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\cos\theta_p = \cos\theta_s \cos\theta_m + \sin\theta_s \sin\theta_m \cos D$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;but not sure how without declination angle D.&lt;/p&gt;&#xA;" OwnerUserId="1230" LastEditorUserId="39" LastEditDate="2014-11-26T13:52:09.133" LastActivityDate="2014-11-26T13:52:09.133" Title="Help determining virtual geomagnetic pole" Tags="|paleomagnetism|homework|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2906" PostTypeId="2" ParentId="2905" CreationDate="2014-11-26T09:41:07.313" Score="7" Body="&lt;p&gt;You say you're &quot;not given the declination angle&quot;, but you also say &quot;the horizontal direction of magnetism of these lavas is due west&quot;. That's your declination angle, right there! Since I assume (from the very round-numbered location) that this is a homework exercise or similar, I won't work through the rest of the calculation here. However, if you need more guidance on VGP calculation, I can recommend Chapter 7 of &lt;a href=&quot;http://www.geo.arizona.edu/Paleomag/book/&quot;&gt;Robert F. Butler's freely available book&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="94" LastActivityDate="2014-11-26T09:41:07.313" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2907" PostTypeId="1" CreationDate="2014-11-25T08:38:09.693" Score="9" ViewCount="8815" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/SBLdn.png&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why do some countries have a lot of oil reserves, while some others don't?&lt;/p&gt;&#xA;" OwnerUserId="17069" OwnerDisplayName="user50746" LastEditorUserId="28050" LastEditDate="2014-11-26T13:13:29.033" LastActivityDate="2014-11-26T17:21:47.373" Title="Why is there so much oil in Saudi Arabia, Venezuela and Canada, but almost none in Europe?" Tags="|economic-geology|petroleum|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2908" PostTypeId="2" ParentId="2907" CreationDate="2014-11-25T19:55:01.290" Score="-4" Body="&lt;p&gt;The amount of oil in the ground is an indicator of how much life used to be there. So, we can conclude that those areas that have a large amount of oil were those that had more vegetation millions of years ago.&lt;/p&gt;&#xA;" OwnerDisplayName="Andrew Lalis" LastActivityDate="2014-11-25T19:55:01.290" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2909" PostTypeId="2" ParentId="2907" CreationDate="2014-11-26T13:12:26.127" Score="14" Body="&lt;p&gt;I wouldn't say there's 'almost none' in Europe, but the global distribution of petroleum is uneven. The reason is that petroleum systems need a convergence of conditions that is relatively rare.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a start, the comment about the inappropriateness of a political map for this purpose is spot on. &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/b/b3/World_petroleum_systems.png/1280px-World_petroleum_systems.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;This USGS map&lt;/a&gt; of global petroleum systems, and non-petroleum-rich basins, is much better — apart from the fact that it perversely omits the USA's substantial endowment: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/epJ9z.png&quot; alt=&quot;World petroleum systems&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These 'petroleum systems' are essentially modern or ancient sedimentary basins with a particular combination of features. I'll refer to a previous answer about a specific region: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2811/why-would-there-be-no-hydrocarbons-in-the-sveconorwegian-belt/2819#2819&quot;&gt;Why would there be no hydrocarbons in the Sveconorwegian belt?&lt;/a&gt; Paraphrasing, and self-plagiarizing, here's what you need for a hydrocarbon (oil or gas) accumulation:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;A &lt;a href=&quot;https://en.wikipedia.org/wiki/Kerogen&quot; rel=&quot;nofollow noreferrer&quot;&gt;kerogen&lt;/a&gt;-rich source rock that has been 'cooked' to thermal maturity. So you need lots of organic matter, burial, and time.&lt;/li&gt;&#xA;  &lt;li&gt;A migration pathway from the source to a trapping configuration, and time for this to have happened.&lt;/li&gt;&#xA;  &lt;li&gt;A structural or stratigraphic trap, such as an anticline, and the geological conditions that have preserved it since filling.&lt;/li&gt;&#xA;  &lt;li&gt;A reservoir rock — a porous and permeable rock. Usually this is a sedimentary rock (like sandstone, which there's lots of in Saudi!).&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;  &#xA;  &lt;p&gt;Only 'conventional' hydrocarbon deposits, such as you might find in&#xA;  the North Sea, Saudi Arabia, or the Gulf of Mexico, need all these&#xA;  conditions. 'Shale gas' is basically just a mature source rock — we&#xA;  can extract hydrocarbons from it by fracking, for example.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So the map of global petroleum resources is a map of places where these criteria converge. Certain deltas are prolific (Mississippi, Niger), because you have rapid burial of sand and organic material. In other places, one or more of the conditions has not been met. Much of Canada, for example, is exposed basement granite: none of the components are there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The unevenness is exacerbated by &lt;a href=&quot;https://en.wikipedia.org/wiki/Pareto_distribution&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Pareto distribution&lt;/a&gt; of system productivity — as with most natural things, we have a few giants, and a long tail. So &lt;a href=&quot;https://en.wikipedia.org/wiki/Western_Canadian_Sedimentary_Basin&quot; rel=&quot;nofollow noreferrer&quot;&gt;the WCSB&lt;/a&gt; and Saudi stick out as anomalous, making the distribution even more 'lumpy'.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-11-26T17:21:47.373" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2910" PostTypeId="2" ParentId="2907" CreationDate="2014-11-26T13:20:07.940" Score="7" Body="&lt;p&gt;The map shown in the question is of proven oil reserves that can be extracted under current conditions.  However, it is really showing you the distribution of oil reserves in a political sense, which is not fundamental to the source of petroleum reserves.  Instead, you should look at the geology that is responsible for oil reserves.  I like the description here:  &lt;a href=&quot;http://large.stanford.edu/courses/2013/ph240/malyshev2/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://large.stanford.edu/courses/2013/ph240/malyshev2/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Regions where the ancient precambrian igneous rocks are exposed at the surface of the Earth are called shields. The world oil reserves are not found in the shields but in orogens which are regions between tectonic plates that experience deformation forces due to the motion of the plates. These forces create basins: areas of deep sedimentary rocks which are necessary to produce the oil. The forces also deform the sedimentary rocks which leads to creation of traps necessary for oil and gas accumulation. The basins and orogens coincide with many oil reach regions: east and west costs of America, around the Persian gulf, along the Ural mountains, across the Caspian sea, in Siberia, in the north of Africa.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;More information on the origin of petroleum reserves is also found here  &lt;a href=&quot;http://en.wikipedia.org/wiki/Petroleum#Formation&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://en.wikipedia.org/wiki/Petroleum#Formation&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Petroleum is a fossil fuel derived from ancient fossilized organic materials, such as zooplankton and algae. Vast quantities of these remains settled to sea or lake bottoms, mixing with sediments and being buried under anoxic conditions. As further layers settled to the sea or lake bed, intense heat and pressure build up in the lower regions. This process caused the organic matter to change, first into a waxy material known as kerogen, which is found in various oil shales around the world, and then with more heat into liquid and gaseous hydrocarbons via a process known as catagenesis. Formation of petroleum occurs from hydrocarbon pyrolysis in a variety of mainly endothermic reactions at high temperature and/or pressure.  There were certain warm nutrient-rich environments such as the Gulf of Mexico and the ancient Tethys Sea where the large amounts of organic material falling to the ocean floor exceeded the rate at which it could decompose. This resulted in large masses of organic material being buried under subsequent deposits such as shale formed from mud. This massive organic deposit later became heated and transformed under pressure into oil.&lt;/p&gt;&#xA;&lt;p&gt;Three conditions must be present for oil reservoirs to form: a source rock rich in hydrocarbon material buried deep enough for subterranean heat to cook it into oil, a porous and permeable reservoir rock for it to accumulate in, and a cap rock (seal) or other mechanism that prevents it from escaping to the surface. Within these reservoirs, fluids will typically organize themselves like a three-layer cake with a layer of water below the oil layer and a layer of gas above it, although the different layers vary in size between reservoirs. Because most hydrocarbons are less dense than rock or water, they often migrate upward through adjacent rock layers until either reaching the surface or becoming trapped within porous rocks (known as reservoirs) by impermeable rocks above. However, the process is influenced by underground water flows, causing oil to migrate hundreds of kilometres horizontally or even short distances downward before becoming trapped in a reservoir. When hydrocarbons are concentrated in a trap, an oil field forms, from which the liquid can be extracted by drilling and pumping.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-11-26T16:58:28.067" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2911" PostTypeId="1" AcceptedAnswerId="2933" CreationDate="2014-11-26T19:52:29.297" Score="12" ViewCount="703" Body="&lt;p&gt;When looking Weather Station readings from the National Weather Service website, what does the term &quot;&lt;strong&gt;Snow Interval (inches)&lt;/strong&gt;&quot; actually mean?  6 hr and 24 hr readings are obvious, but I can't seem to connect the dots to &quot;Snow Interval&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For an example, look &lt;a href=&quot;http://www.wrh.noaa.gov/mesowest/getobext.php?wfo=mso&amp;amp;sid=BIGMS&amp;amp;num=168&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="1231" LastEditorUserId="64" LastEditDate="2014-11-27T00:43:04.490" LastActivityDate="2016-01-03T01:57:47.893" Title="What does the term &quot;Snow Interval&quot; mean?" Tags="|meteorology|measurements|terminology|weather-forecasting|snow|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2912" PostTypeId="2" ParentId="2895" CreationDate="2014-11-26T20:10:04.977" Score="5" Body="&lt;p&gt;The actual cause of the Cameroon Line is described by many authors (including the 2 included in this answer as being source of controversy and uncertainty - but it seems that it is not an active rift system, certainly not like the east Africa Rift.  According to the article &lt;a href=&quot;http://www1.gly.bris.ac.uk/~ibastow/DOCS/Milelli.pdf&quot; rel=&quot;noreferrer&quot;&gt;A lithospheric instability origin for the Cameroon Volcanic Line&lt;/a&gt; (Milelli et al. 2012) describe the Cameroon Volcanic Line (CVL) as being &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;an enigmatic structure that defies common dynamic models of&#xA;  melt generation and volcanic activity on Earth.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The enigma is due to the CVL having no spatial age progression in the rift system, despite having continual magma intrusion over 70 million years along the 1600 onshore-offshore line. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The authors also suggest that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The chain is nearly perpendicular to the coastline and&#xA;  terminates in a Y-shaped structure that has not been affected by absolute plate motions, &lt;strong&gt;implying that&#xA;  the mantle upwelling that feeds magmatic activity is attached to the continent.&lt;/strong&gt; &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The authors model that rather than a developing rift system, the CVL is likely to be an example of where the lithosphere becomes unstable due to cooling from the crust above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It should be noted that the CVL lies in between 2 cratons, shown as white in the seismic tomography image below from &lt;a href=&quot;http://gemoc.mq.edu.au/Annualreport/annrep2008/Indust08.html&quot; rel=&quot;noreferrer&quot;&gt;Macquarie Universty&lt;/a&gt; - what also should be noted, is the colour of the active East African Rift.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/mfD1T.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further, according to the article &lt;a href=&quot;http://web.mst.edu/~sgao/publications/Elsheikh_Gao_JAES_Cameroon.pdf&quot; rel=&quot;noreferrer&quot;&gt;Formation of the Cameroon Volcanic Line by lithospheric basal erosion:&#xA;Insight from mantle seismic anisotropy&lt;/a&gt; (Elsheikh et al. 2014), modelled the sub-crust dynamics that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;involves a channel flow at the bottom of the lithosphere originated from the&#xA;  NE-ward movement of the asthenosphere relative to the African plate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;from this, the authors hypothesise that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;progressive&#xA;  thinning of the lithosphere through basal erosion by the flow leads to decompression melting and is&#xA;  responsible for the formation of the CVL. The model is consistent with the lack of age progression of&#xA;  the volcanoes in the CVL, can explain the formation of both the continental and oceanic sections of the&#xA;  CVL, and is supported by previous geophysical observations and geodynamic modeling results.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A key conclusion the authors made regarding the flood basalts and volcanism in the CVL is that observations do not support mantle convection or mantle plume causes, rather, they assert that basal lithospheric erosion due to&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;concentration of mantle flow associated with the&#xA;  sharp change in the orientation of the continental margin of western&#xA;  Africa.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-11-26T20:10:04.977" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2913" PostTypeId="1" AcceptedAnswerId="2915" CreationDate="2014-11-27T09:07:14.600" Score="8" ViewCount="540" Body="&lt;p&gt;The Bonarelli Event (a.k.a. OAE2) is a well-studied episode of &quot;worldwide&quot; oceanic anoxic event at the Cenomanian-Turonian boundary (ca. 94 Ma). It is characterized by the presence of organic-rich marine sediments and a $\mathrm{\delta^{13}C}$ shift. It is thought to have provoked a minor mass extinction and an increased atmospheric and oceanic temperature.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What evidence do we have that the anoxia was indeed global?&lt;br&gt;&#xA;Is there really no known ocean basin with sediments spanning this time interval that doesn't show those characteristic black shales?&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="725" LastEditDate="2014-12-01T07:06:50.587" LastActivityDate="2014-12-01T07:08:24.227" Title="How global was the Bonarelli Oceanic Anoxic Event?" Tags="|oceanography|paleoclimatology|cretaceous|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2914" PostTypeId="1" AcceptedAnswerId="4606" CreationDate="2014-11-27T10:00:03.633" Score="15" ViewCount="585" Body="&lt;p&gt;Paleoclimate data often derives from sedimentary rocks. Metamorphic rocks can also contribute to paleoclimate information in a wide variety of ways.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What about igneous rocks? I guess that this can question be divided into two, about intrusive and extrusive rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Extrusive rocks will have direct contact with the climate. They may exchange geochemical signals with the atmosphere or water they've erupted to. The cooling rate may be dependent on ambient temperature. Lava flows may fossilise the soil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Intrusive rocks may be harder to interpret in that manner, if at all. The time resolution will obviously not be as good as dating individual beds from the lake floor, but I still think something can be gained from it. Maybe some igneous rocks can form only after a special sedimentary rock (derived from a specific climate) has been buried and remelted? What about isotopes? Sedimentay systems often fractionate various isotopic systems. Can this variability be later traced in igneous rocks?&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-08-26T05:16:59.253" Title="What, if any, paleoclimate data can be derived from igneous rocks?" Tags="|volcanology|geochemistry|paleoclimatology|igneous|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2915" PostTypeId="2" ParentId="2913" CreationDate="2014-11-27T10:55:22.743" Score="8" Body="&lt;p&gt;Recent research and models, based on sulphur and carbon radioisotope data, reported in the article &lt;a href=&quot;http://www.pnas.org/content/110/46/18407.full&quot; rel=&quot;nofollow&quot;&gt;Sulfur isotopes track the global extent and dynamics of euxinia during Cretaceous Oceanic Anoxic Event 2&lt;/a&gt; (Owens et al. 2013) suggest that the oxygen-free and hydrogen sulfide-rich waters extended across &lt;strong&gt;roughly 5% of the global ocean&lt;/strong&gt;, compared to &amp;lt;&amp;lt;1% today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Owens et al. model results place important controls on local conditions, rather than global conditions and point to the difficulty in sustaining whole-ocean euxinia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The models based on the sulphur and carbon isotopes suggest that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the excursions were driven by increased burial of pyrite and OC. Although generally coupled, these C- and S-isotope excursions show a pronounced offset between peak magnitudes. The observed offset between these isotope signatures may not be unique in the geologic record but is certainly a pronounced characteristic of OAE 2.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and crucially, in terms of local over global controls,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The spatial variability in the excursion magnitudes could be due to local watermass differences and/or varying riverine fluxes to an ocean with substantially lower than modern sulfate concentrations, an effect noted also for the Toarcian OAE*&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Further explanations are provided in the article &lt;a href=&quot;http://dro.dur.ac.uk/11728/1/11728.pdf&quot; rel=&quot;nofollow&quot;&gt;Marine $\mathrm{^{187}Os/^{188}Os}$ isotope stratigraphy reveals the interaction&#xA;of volcanism and ocean circulation during Oceanic Anoxic Event 2&lt;/a&gt; (du Vivier et al. 2014), who found that, through analysis of marine $\mathrm{^{187}Os/^{188}Os}$ isotope stratigraphy&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;differential input of nutrients from continental and volcanogenic&#xA;  sources, coupled with efficient palaeocirculation of the global ocean and epeiric seas, enhanced&#xA;  productivity due to higher nutrient availability, which permitted penecontemporaneous transport of&#xA;  continental and LIP-derived nutrients to trans-equatorial basins.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;LIP = Large Igneous Provinces&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and that the tipping point was rising sea levels at the time, further, the authors suggest that from local sources and igneous activity, coupled with rising sea levels and palaeo-oceanic circulation at the time, concluding with the evidence suggesting a global reach of the anoxic event:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The close similarity of $\mathrm{Os_i}$ profiles from ∼50 kyr prior to the OAE 2 and through out the syn-OAE 2 interval indicates that transgression progressed to a point where a homogeneous global seawater signal was delivered to  multiple proto-transatlantic basins by active ocean circulation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This suggests that the anoxic event started locally with weathering from the land surface, coupled with large igneous province (LIP) activity, progressing due to rising sea levels and palaeo-oceanic circulation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Additional references&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*Newton et al. 2013, &lt;a href=&quot;http://geology.gsapubs.org/content/39/1/7.abstract?ijkey=b2b2725d873045cafb131d982e81bf772d1a3077&amp;amp;keytype2=tf_ipsecsha&quot; rel=&quot;nofollow&quot;&gt;Low marine sulfate concentrations and the isolation of the European epicontinental sea during the Early Jurassic&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="725" LastEditDate="2014-12-01T07:08:24.227" LastActivityDate="2014-12-01T07:08:24.227" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2916" PostTypeId="1" AcceptedAnswerId="2936" CreationDate="2014-11-27T13:21:19.650" Score="13" ViewCount="197" Body="&lt;p&gt;Right now I'm in the middle of writing my master thesis which is about modelling the ocean bottom pressure (obp) under areas with sea-ice coverage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In most Oceanic General Circulation Model's (ogcm) obp is calculated prognostically, so it's basically just the sum of the sea-surface height $\zeta$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/grl.50265/abstract&quot; rel=&quot;nofollow&quot;&gt;Recent studies&lt;/a&gt; show an increase in $\zeta$ for regions with continental shelf within a reasonable timespan, so I was wondering how much of the arctic sea is above continental shelf? I know it is probably a lot, but are there any numbers, units of $\text{km}^{2}$?&lt;/p&gt;&#xA;" OwnerUserId="1228" LastEditorUserId="725" LastEditDate="2014-12-19T15:22:41.490" LastActivityDate="2014-12-19T15:22:41.490" Title="How much of the underwater land masses within the arctic ocean is considered continental shelf?" Tags="|ocean|oceanography|sea-level|sea-ice|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2917" PostTypeId="1" CreationDate="2014-11-27T15:11:34.103" Score="12" ViewCount="405" Body="&lt;p&gt;I'm not completely clear on what &lt;a href=&quot;http://en.wikipedia.org/wiki/Boundary_current#Western_intensification&quot;&gt;Western intensification&lt;/a&gt; means, but it looks like a pretty powerful (combination of) forces that presumably wouldn't be likely to change on a timescale of years (or even decades, centuries).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I recall reading some time ago that global warming is already known to be causing a significant increase in the amount of &lt;em&gt;fresh&lt;/em&gt; (as opposed to salt) water being introduced into the system at the European end. I assume that's &quot;one-time-only&quot; melting of glaciers and snow/ice in areas that were previously permafrost, but for all I know there could be much more simply arising from a (potential) massive increase in precipitation across north-western Europe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I freely admit I don't know the relative importance of warm/cold salty/fresh water in the thermodynamics of the Gulf Stream system, which is probably relevant. But what I really want to know is...&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;Do we understand the Gulf Stream well enough to answer the question posed in my title?&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="1234" LastEditorUserId="192" LastEditDate="2014-11-27T16:22:47.250" LastActivityDate="2015-01-09T01:33:38.693" Title="How stable is the Gulf Stream? Could it stop suddenly?" Tags="|oceanography|global-warming|ocean-currents|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2918" PostTypeId="1" AcceptedAnswerId="2925" CreationDate="2014-11-27T20:41:26.753" Score="9" ViewCount="351" Body="&lt;p&gt;NASA Planetary Scientists released a video that says they have confirmed that there is an underground ocean in Europa and that Titan has liquid oceans made of hydrocarbons. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I myself am an aspiring planetary geologist and current student, the only instrument I have seen them using is the spacecrafts orbiting these moons. &lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="725" LastEditDate="2014-11-29T17:04:31.780" LastActivityDate="2014-11-29T17:04:31.780" Title="What sort of instruments do planetary geologists use to predict that there are oceans on the moons Titan and Europa?" Tags="|planetary-science|remote-sensing|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2919" PostTypeId="2" ParentId="2888" CreationDate="2014-11-28T11:05:18.887" Score="5" Body="&lt;p&gt;The Igwisi Hills kimberlites erupted through the Archaean aged Tanzanian Craton, which resides in between the eastern and western branches of the East Africa Rift (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2002JB002273/full&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt;), in the vicinity of the Gregory Rift (&lt;a href=&quot;http://link.springer.com/article/10.1007%2FBF00310913&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;). It is a series of 3 volcanoes, evidence has shown that these eruptions were the result small volume monogenetic eruptions (&lt;a href=&quot;http://research-information.bristol.ac.uk/en/publications/eruption-of-kimberlite-magmas-physical-volcanology-geomorphology-and-age-of-the-youngest-kimberlitic-volcanoes-known-on-earth-the-upper-pleistoceneholocene-igwisi-hills-volcanoes-tanzania(cd277b49-99ee-43ca-8cd4-515b38db21be).html&quot; rel=&quot;nofollow&quot;&gt;3&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seismic studies and observations detected that the cratonic lithosphere base is approximately 170km, after which, there is anomalously low velocities to a depth of about 350km (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2002JB002273/full&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt;), which according to models described by Weeraratne et al. (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2002JB002273/full&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt;) indicate that beneath the cratonic crust, there is the presence of high temperature and the presence of melt:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;a transition to a younger 'more fertile' asthenosphere.&lt;/li&gt;&#xA;&lt;li&gt;crucially in terms of the local tectonics, indicate the presence of a mantle plume head causing the craton to experience uplift.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The mineralogy of xenoliths in the pyroclasts and lava further indicate that there has been small degrees of carbonate-apatite bearing peridotite source melts from depths greater than 110km. (&lt;a href=&quot;http://link.springer.com/article/10.1007%2FBF00310913&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Brown et al. (&lt;a href=&quot;http://research-information.bristol.ac.uk/en/publications/eruption-of-kimberlite-magmas-physical-volcanology-geomorphology-and-age-of-the-youngest-kimberlitic-volcanoes-known-on-earth-the-upper-pleistoceneholocene-igwisi-hills-volcanoes-tanzania(cd277b49-99ee-43ca-8cd4-515b38db21be).html&quot; rel=&quot;nofollow&quot;&gt;3&lt;/a&gt;) conclude that the fact that these kimberlitic volcanics are so comparatively young, they may indicate that a new phase of kimberlite activity may be starting in the Tanzanaian craton, especially when considering the mantle plume and active rifting in the adjacent East Africa Rift branches.  This suggests that a link between kimberlite volcanism and the supercontinent cycle maybe too much of a simplistic view, when the reality is probably closer to individual plate reorganisation (in this case, the eventual splitting of the African continent). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2002JB002273/full&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt;) Weeraratne et al. 2003, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2002JB002273/full&quot; rel=&quot;nofollow&quot;&gt;Evidence for an upper mantle plume beneath the Tanzanian craton from Rayleigh wave tomography&lt;/a&gt;, Journal and Geophysical Research.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://link.springer.com/article/10.1007%2FBF00310913&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;) Dawson, 1994, &lt;a href=&quot;http://link.springer.com/article/10.1007%2FBF00310913&quot; rel=&quot;nofollow&quot;&gt;Quaternary kimberlitic volcanism on the Tanzania Craton&lt;/a&gt;, Contributions to Mineralogy and Petrology (abstract only - paywalled)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://research-information.bristol.ac.uk/en/publications/eruption-of-kimberlite-magmas-physical-volcanology-geomorphology-and-age-of-the-youngest-kimberlitic-volcanoes-known-on-earth-the-upper-pleistoceneholocene-igwisi-hills-volcanoes-tanzania(cd277b49-99ee-43ca-8cd4-515b38db21be).html&quot; rel=&quot;nofollow&quot;&gt;3&lt;/a&gt;) Brown et al. 2012, &lt;a href=&quot;http://research-information.bristol.ac.uk/en/publications/eruption-of-kimberlite-magmas-physical-volcanology-geomorphology-and-age-of-the-youngest-kimberlitic-volcanoes-known-on-earth-the-upper-pleistoceneholocene-igwisi-hills-volcanoes-tanzania(cd277b49-99ee-43ca-8cd4-515b38db21be).html&quot; rel=&quot;nofollow&quot;&gt;Eruption of kimberlite magmas: physical volcanology, geomorphology and age of the youngest kimberlitic volcanoes known on earth (the Upper Pleistocene/Holocene Igwisi Hills volcanoes, Tanzania)&lt;/a&gt;, Explore Bristol Research (abstract only - paywalled)&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-11-29T12:01:45.867" LastActivityDate="2014-11-29T12:01:45.867" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2920" PostTypeId="2" ParentId="2917" CreationDate="2014-11-28T11:32:14.773" Score="7" Body="&lt;p&gt;There's a pretty good rundown of this issue over at &lt;a href=&quot;http://www.realclimate.org/index.php/archives/2005/05/gulf-stream-slowdown/&quot;&gt;RealClimate&lt;/a&gt;, and a &lt;a href=&quot;http://en.wikipedia.org/wiki/Shutdown_of_thermohaline_circulation&quot;&gt;wikipedia article dedicated to the topic&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A summary of the main points from there:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The Gulf Stream is part of the Meridional Overturning Current (global ocean conveyor), which is primarily wind-driven, and secondarily thermohaline-driven. The Gulf Stream itself is also primarily wind-driven.&lt;/li&gt;&#xA;&lt;li&gt;There has been some reduction of the thermohaline drivers in the north Atlantic, due to increased temperatures, and influxes of fresh water, largely from melting of the Siberian permafrost. This part of the system does fluctuate (as do most parts), but there does appear to be a trend.&lt;/li&gt;&#xA;&lt;li&gt;These changes are not enough threaten the Gulf Stream, and there hasn't really been any observations of an over-all slow down that couldn't be otherwise explained by natural variation.&lt;/li&gt;&#xA;&lt;li&gt;It is likely that the Gulf Stream &lt;em&gt;will&lt;/em&gt; slow down over the next few centuries (slow downs appear in some of the IPCC models out to 2100).&lt;/li&gt;&#xA;&lt;li&gt;A complete shut-down is possible (it has happened before, notably during the Younger Dryas), but it is hard to predict, as causes are not very well understood. But it seems unlikely to happen any time soon.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="56" LastActivityDate="2014-11-28T11:32:14.773" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2921" PostTypeId="2" ParentId="2914" CreationDate="2014-11-28T16:02:14.820" Score="3" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/K%E2%80%93Ar_dating&quot; rel=&quot;nofollow&quot;&gt;Potassium–argon (K-Ar) dating&lt;/a&gt; specifically and &lt;em&gt;only&lt;/em&gt; works with igneous rocks. The idea being that when molten magma solidifies into, say, granite or basalt, any potassium ends up locked into crystaline forms. Some of that potassium will be the unstable K-40 isotope, decaying into A-40 with a half-life of 1.26 billion years. Since virtually &lt;em&gt;no&lt;/em&gt; A-40 would have been present at time of crystalisation, the K-40:A-40 ratio gives a good indication of when solidification occurred.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are of course other &quot;radioactive clocks&quot; based on other elements/isotopes with longer or short half-lives, which may be more suitable depending on how far back you're trying to look. And although we're not likely to find much in the way of organic material (fossils, etc.) in igneous rocks, information from different sources can usefully be collated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know of any specific case, but I'd have thought there would be many situations where sedimentary rock has been laid down over precisely-dated igneous rocks. And I don't know the exact limitations of &lt;a href=&quot;http://en.wikipedia.org/wiki/Dendrochronology&quot; rel=&quot;nofollow&quot;&gt;dendrochronology&lt;/a&gt;, but it seems at least &lt;em&gt;possible&lt;/em&gt; that you could detect identifiable &quot;pattern sequences&quot; in ancient annual tree-trunk ring growth patterns that suddenly become far more meaningful if you know &lt;em&gt;when&lt;/em&gt; those patterns were formed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some seasonal growth variation will be down to local factors, and some will reflect &quot;global&quot; events. But given enough data, they could be distinguished. It should be possible to collate information from, say, K-Ar dating and dendrochronology to derive &lt;em&gt;more&lt;/em&gt; information that is directly available from either source. And the whole is greater than the sum of the parts, as they say.&lt;/p&gt;&#xA;" OwnerUserId="1234" LastActivityDate="2014-11-28T16:02:14.820" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="2922" PostTypeId="2" ParentId="2745" CreationDate="2014-11-28T21:00:26.823" Score="5" Body="&lt;p&gt;There is considerable evidence that as the East African rift system is still developing, that it is not been possible to delineate southern rifting structures, which would extend into the Indian Ocean south of Madagascar. Looking at the evidence found in recent studies confirm this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First to set the overall tectonic scene by Saemundsson &lt;strong&gt;(1)&lt;/strong&gt;, the East African Rift is a series of parallel rifts, particularly the east and west rift systems.  Rifting is propagating southwards, with rifting rates decreasing from 2.6 cm/year in the Red Sea area to less than 0.5 mm/year south of Kenya/Tanzania.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The entire rifting region is seismically active, with seismicity extending south into Mozambique, as can be seen in the earthquake map below &lt;strong&gt;(2)&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/SnJ8U.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are no recorded earthquakes extending from the African continent to the plate boundaries to the south or east.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://epss.ucla.edu/people/faculty/545/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Peter Bird, of UCLA&lt;/a&gt;, published observations of the stress and strain features of southern Africa, particularly as the southern extension of the East African Rift provides a unique opportunity to observe new plate boundary formation.  Observational evidence provided by Bird et al &lt;strong&gt;(3)&lt;/strong&gt; have found that there may be some very slow rotation of the developing 'Somali Plate' (East African plate) with respect to the 'Nubian plate' (rest of Africa) which is meeting resistance through an unbroken lithosphere - which may also partly explain the different spreading rate in the rift itself from north to south &lt;strong&gt;(1)&lt;/strong&gt; (mentioned above).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The stress direction model developed by Bird et al. is shown below &lt;strong&gt;(3)&lt;/strong&gt;, what can be see is that the normal faulting from the East African Rift continues someway off the coast of Mozambique, becoming transversal (strike-slip), leading to a compressive feature (thrust faulting) near the plate boundary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/KLDDW.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More studies would be required in the Indian Ocean off the coast of Mozambique would be required to definitively determine the extent and dynamics of this &lt;em&gt;possible&lt;/em&gt; southern extent of the East African rift.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1) Saemundsson, 2010, &lt;a href=&quot;http://www.os.is/gogn/unu-gtp-sc/UNU-GTP-SC-11-18.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;East African Rift: An Overview&lt;/a&gt;, Presented at Short Course V on Exploration for Geothermal Resources&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) Midzi et al. &lt;a href=&quot;http://www.seismo.ethz.ch/static/gshap/earift/report.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seismic Hazard Assessment in Eastern and Southern Africa&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(3) Bird et al. 2006, &lt;a href=&quot;http://peterbird.name/publications/2006_South_Africa/2005JB003882.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Patterns of stress and strain rate in southern Africa&lt;/a&gt;, Journal of Geophysical Research&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-11-28T21:00:26.823" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2923" PostTypeId="1" AcceptedAnswerId="2924" CreationDate="2014-11-28T22:27:52.337" Score="8" ViewCount="288" Body="&lt;p&gt;In thinking about the question, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/651/why-is-earths-axis-tilted&quot;&gt;Why is earth's axis tilted?&lt;/a&gt;, and reading articles about Earth's axial tilt, I came across the website &lt;a href=&quot;http://www.snowballearth.org/alternatives.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Snowball Earth&lt;/a&gt; which describes an alternate theory for global glaciation proposed by &lt;a href=&quot;http://www.adelaide.edu.au/directory/george.williams&quot; rel=&quot;nofollow noreferrer&quot;&gt;George Williams&lt;/a&gt;, from the University of Adelaide - what is proposed is that the Earth had a considerably higher axial obliquity (greater than 54°) up to about 600 million years ago. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Professor Williams proposes that this could be a mechanism for Snowball Earth events and cites the 'explosion' of life occurring after the axial tilt stabilised, thus causing the seasonal changes to become less severe with lower obliquity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is related to the question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2498/what-sort-of-climate-zones-would-be-present-if-earth-was-tilted-like-uranus&quot;&gt;What sort of climate zones would be present if Earth was tilted like Uranus?&lt;/a&gt;, but asks the question if there is &lt;strong&gt;evidence that Earth did have a greater axial obliquity in the Proterozoic?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-11-29T08:28:34.547" Title="Could Earth have had a greater axial tilt?" Tags="|earth-rotation|precambrian|axial-obliquity|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2924" PostTypeId="2" ParentId="2923" CreationDate="2014-11-29T03:41:14.133" Score="8" Body="&lt;p&gt;There is no evidence that Earth had a much greater axial tilt so long ago.  To my knowledge, the evidence for changes in the axial tilt of the Earth is based on ocean sediment cores (see &lt;a href=&quot;http://en.wikipedia.org/wiki/James_Hays&quot;&gt;http://en.wikipedia.org/wiki/James_Hays&lt;/a&gt; ) and ice cores ( see &lt;a href=&quot;http://en.wikipedia.org/wiki/Milankovitch_cycles#Axial_tilt_.28obliquity.29&quot;&gt;http://en.wikipedia.org/wiki/Milankovitch_cycles#Axial_tilt_.28obliquity.29&lt;/a&gt; ).  However, these only go back 100s of thousands of years.  There is no record that I know of that could be used to assess the axial tilt of Earth 100s of millions of years ago.  However, you could speculate that after the collision that Earth had that led to our moon, the axial tilt could have been much greater as a result.  However, all records that I have seen show that the axial tilt fluctuates from 22.1 to 24.5 degrees.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2014-11-29T03:41:14.133" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2925" PostTypeId="2" ParentId="2918" CreationDate="2014-11-29T15:51:12.883" Score="8" Body="&lt;p&gt;As &lt;a href=&quot;https://earthscience.stackexchange.com/users/64/casey&quot;&gt;casey&lt;/a&gt; said, the satellite isn't an instrument in itself, it is a platform hosting many instruments. What you're talking about the discovery of oceans on Titan and Europa, you're referring to the the Cassini-Huygens mission aimed at, among other things : &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Determine the composition of the satellites surfaces (such as Titan)&lt;/li&gt;&#xA;&lt;li&gt;Prove or disprove the existence of oceans or water on those satellites.&lt;/li&gt;&#xA;&lt;li&gt;Characterize Titan's surface on a regional scale&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In order to establish the existence of oceans or water on those satellites, scientists use:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Spectroscopy&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;More precisely, absorption spectroscopy. AS is an analytical chemistry tool used to determine the presence of a substance in a sample. Thanks to a spectrometer, you'll be able to gather a lot of information about the elements on this Moon, and by further analysis, determine if there's water or no. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;N.B&lt;/em&gt; : &lt;em&gt;I am not talking about liquid water, but about water. Science now establishes the validity of certain signatures, but liquid water is to be confirmed.&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What about Cassini?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cassini used a lot of spectrometers : the VIMS (&lt;strong&gt;Visible and Infrared Mapping Spectrometer&lt;/strong&gt;) was used on the satellite to gather information on the surface. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Our instrument measures the characteristic colors of the many materials that make up planetary surfaces and atmospheres: rocks, ices -- such as water, ammonia, methane -- and organic compounds,&quot; says Dr. Bonnie J. Buratti, VIMS Investigation Scientist. &quot;VIMS data makes it possible to know what surfaces and atmospheres are made up of.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/j8p9n.jpg&quot; alt=&quot;Image taken from the spectrometer&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Volcanic observation&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Indicators such as Geysers can be used to support the theory of water presence in subsoil. If by any radars, such as the ISS from Cassini (&lt;strong&gt;Imaging Science Subsystem&lt;/strong&gt;), you can see geysers, then you can search about the possibility of water. Why? Because as you may know, water is pressurized in subsoil. Then, when water is heated by the heat of rocks, and it will tend to result in a geyser.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/MVLQP.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="1138" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-11-29T15:51:12.883" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2926" PostTypeId="2" ParentId="2573" CreationDate="2014-11-29T17:02:34.767" Score="7" Body="&lt;p&gt;A fairly recent article by the Geological Society of America: &lt;a href=&quot;http://geology.gsapubs.org/content/36/8/671.full.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Arc magmatism, calderas, and supervolcanoes&lt;/a&gt; (de Silva, 2008) states that VEI-8 (or volcanoes that release 1000 km$^3$ of tephra) are classed as being supervolcanic - and something that we have not witnessed in recorded history.  Specifically, the author describes VEI-8 (and greater) eruptions to be the result of 'supervolcanic caldera forming event flare ups'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, de Silva characterises the volcanism for this type of event as requiring a thermal and physical environment that can support storage and the mantle basaltic flux for the production of massive silicic magma.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As according to several authors including Siebert et al. (&lt;em&gt;book: Volcanoes of the World&lt;/em&gt;), there is no evidence of a VEI-9 eruption found yet, the best way to think about this question is to imagine a majorly upscaled version of a VEI-8 supervolcano, such as Toba or Yellowstone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, the geological events for a hypothesised VEI-9 eruption would need (adapted from de Silva):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;the development of a magma chamber that could support the magma that would be fragmented to produce at least 10,000+ km$^3$ of volcanic ash - this would probably result in major uplift in the area, with faulting around the edges.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;flare up conditions that are the result of elevated power input from the mantle resulting in a major shift to an increase in silicic magma productivity - this could include a massive array of geysers (if water were present), heating of the ground, possibly widespread gas vents.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;the thermomechanical evolution of the crust through a positive feedback between mantle power, mantle production, heat advection through the crust and the mechanical strength of the crust.  This is where there is enough energy to prevent the magma and crust to cool too quickly.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;a trigger to set the whole pressure cooker off - most likely an earthquake, or a series of quakes that start a caldera collapse for example.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;a recent &lt;a href=&quot;https://phys.org/news/2017-01-triggered-largest-volcanic-eruption-witnessed.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;study&lt;/a&gt; suggests that the assimilation of water bearing crustal rocks into the magma at Toba increased its water content, and therefore, explosivity.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Essentially, a VEI-9 eruption could be classified as a 'megavolcano', the consequences of such a volcanic eruption would be absolutely catastrophic.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="725" LastEditDate="2017-02-01T00:33:35.003" LastActivityDate="2017-02-01T00:33:35.003" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2927" PostTypeId="1" AcceptedAnswerId="2928" CreationDate="2014-11-29T21:54:08.150" Score="7" ViewCount="663" Body="&lt;p&gt;My city's altitude is almost 950 meters, yet the weather stations provide a read of 102.14 kPa which is around 1 atm! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.wolframalpha.com/input/?i=atmospheric%20pressure%20at%20950m&quot;&gt;Shouldn't the pressure be a function of elevation?&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I doubted that the data provided could be wrong, so I checked New York and got almost the very &lt;a href=&quot;http://www.usairnet.com/weather/maps/current/new-york/barometric-pressure/&quot;&gt;same results.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All reading are very close to 30 in.Hg (around 1 atm), yet the elevation varies from 0 to 550m.&#xA;So, what is going on?&lt;/p&gt;&#xA;" OwnerUserId="1239" LastEditorDisplayName="user889" LastEditDate="2014-11-29T22:20:55.230" LastActivityDate="2014-11-29T22:30:05.960" Title="Pressure as a function of altitude" Tags="|meteorology|atmosphere|barometric-pressure|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2928" PostTypeId="2" ParentId="2927" CreationDate="2014-11-29T22:30:05.960" Score="13" Body="&lt;p&gt;The reported pressures are sea level pressure.  For stations not at sea level (most of them), they can be corrected to sea level through use of the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Hypsometric_equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;hypsometric equation&lt;/a&gt;.  The reason the values are reported as sea level pressure is so that pressure values between stations can be interpreted in meaningful ways.  See for example a typical sea level pressure plot:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/mfuaL.gif&quot; alt=&quot;sea level pressure&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to produce such a plot, you need pressures on a common reference plane, which is often mean sea level or some other reference pressure level (e.g. 850mb, 500mb, 250mb).  This is why stations report sea level pressure rather than actual station pressure.  This also has applications for aviation, where aircraft operating below a specific altitude (18,000 ft in the US) have to reference their altimeters to a common value regionally and must know the local sea level pressure.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-11-29T22:30:05.960" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2929" PostTypeId="2" ParentId="2832" CreationDate="2014-11-30T19:14:42.567" Score="10" Body="&lt;p&gt;A main source of meteoritic origin in sedimentary strata could have been likely to have been placed in a marine sedimentary environment as debris from a larger impact. Evidently, as you stated, the older the sediment, the greater the chance of alteration or even complete destruction of any trace of the fragments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to the micrometeorites found in Sweden (as per DavePhD's linked articles), the article &lt;a href=&quot;http://arxiv.org/ftp/arxiv/papers/1408/1408.3524.pdf&quot;&gt;Cosmic-ray exposure ages of fossil micrometeorites from mid-Ordovician&#xA;sediments at Lynna River, Russia.&lt;/a&gt; (Meier et al. 2014), report of observations of chondrite micrometeoritic dust occurring in mid-Ordovician (~ 470 million years ago) sediments found around the Lynna River, Russia, as well as localities in China.  The authors state that the composition of the micrometeoritic sample makes them largely resistant to weathering and diagenesis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The authors of the article &lt;a href=&quot;https://journals.uair.arizona.edu/index.php/maps/article/viewFile/15567/15555&quot;&gt;Noble gases in fossil micrometeorites and meteorites from 470 Myr old&#xA;sediments from southern Sweden, and new evidence&#xA;for the L-chondrite parent body breakup event&lt;/a&gt; (Heck et al. 2008) concluded that it was 'remarkable' that the solar gases trapped in the chromite grains from the Ordovician-aged 'fossil meteorites found in Sweden (and according to Meier et al. 2014, also in Russia and China) have survived not only the heat up due to entry into the Earth's atmosphere, but also the long residence time in the sediments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further back, finding pristine sedimentary layers, let alone intact meteorites within the strata become increasingly difficult to find, so there incorporation into the geology would be in the form of geochemical traces.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A couple of examples of this include the following, the Nature article (Abstract only - paywalled), &lt;a href=&quot;http://www.nature.com/nature/journal/v418/n6896/abs/nature00923.html&quot;&gt;Tungsten isotope evidence from approx 3.8-Gyr metamorphosed sediments for early meteorite bombardment of the Earth&lt;/a&gt; (Schoenberg et al. 2002), suggest that Archaean aged metamorphic rocks found in Greenland and Canada contain tungsten anomalies that can, according to the authors, only be meteoritic remnants in the metamorphosed sediments.  Chemical traces of possible chondritic origin have been hypothesised to have been included in Archaen spherules in metamorphosed sedimentary strata in South Africa, according to the article &lt;a href=&quot;http://www.sciencemag.org/content/245/4921/959.short&quot;&gt;Geological and Geochemical Record of 3400-Million-Year-Old Terrestrial Meteorite Impacts&lt;/a&gt; (Lowe et al. 1989) (Abstract only -paywalled).&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-11-30T19:25:22.797" LastActivityDate="2014-11-30T19:25:22.797" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2930" PostTypeId="2" ParentId="2636" CreationDate="2014-12-01T05:35:33.013" Score="2" Body="&lt;p&gt;Spreadsheets work well for this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You have 12×12 observations so use 144+1 = 145 as the number of observations for calculating your probabilities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Put your discharge data in a column and sort from highest to lowest. Put a column of Rankings next to it and number from 1 up to your maximum (1 to 144). Put a column next to that and calculate your probability of exceeding each discharge value:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;P = Ranking×100/145&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(P as a percent)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Graph discharge vs. P.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You need to consider your 0 discharge months in determining the number of periods but you don't need to calculate P for them.  That's handy if you don't want errors in plotting log discharge vs. P.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastEditorUserId="725" LastEditDate="2014-12-01T07:05:23.557" LastActivityDate="2014-12-01T07:05:23.557" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2931" PostTypeId="1" AcceptedAnswerId="7268" CreationDate="2014-12-01T09:01:07.143" Score="19" ViewCount="1094" Body="&lt;p&gt;In 1973, Hsü &lt;em&gt;et al.&lt;/em&gt; explained the findings of a large evaporite deposit during the Messinian (Latest Miocene stage, ca. 6Ma) in the Mediterranean by a basin-wide desiccation event. It has been speculated later that it was due to the closing of the Gibraltar strait.&lt;br&gt;&#xA;Much research has been done on the subject since then, generating controversies on whether the entire basin became totally or partly desiccated, on the actual cause of the event, on whether the Strait closed because of tectonic activity or because of sea level drop, etc.&lt;br&gt;&#xA;Hence my question: What is the current consensus on the extent of that event and its causes?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Hsü, K. J., Ryan, W. B. F., Cita, M. B. 1973. &lt;a href=&quot;http://dx.doi.org/10.1038/242240a0&quot; rel=&quot;noreferrer&quot;&gt;Late Miocene Desiccation of the Mediterranean&lt;/a&gt;. Nature, 242: 240-244.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="1379" LastEditDate="2016-01-15T11:42:09.773" LastActivityDate="2016-04-11T09:18:12.913" Title="Current consensus on the Messinian Salinity Crisis" Tags="|oceanography|paleoclimatology|mediterranean|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2932" PostTypeId="1" AcceptedAnswerId="2939" CreationDate="2014-12-01T13:16:54.813" Score="17" ViewCount="17112" Body="&lt;p&gt;I'm kind of new to the Large Eddy Simulation (LES) modeling world and I wondered what is the difference between an LES subgrid scale model like the Smagorinsky–Lilly model and a one-equation Reynolds-Averaged Navier-Stokes (RANS) based model like the Spalart-Allmaras. They are both based on the Boussinesq eddy viscosity ($\mu$) hypothesis and both &#xA;using a one-equation approach for modelling $\mu$. However, no one is using the Smagorinsky–Lilly model for RAS or the Spalart-Allmaras for LES.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the difference between these two models and what kind of physical processes are they applied to?&lt;/p&gt;&#xA;" OwnerUserId="1228" LastEditorUserId="1228" LastEditDate="2014-12-02T20:53:54.790" LastActivityDate="2014-12-03T06:17:52.243" Title="What are the differences between an LES-SGS model and a RANS based turbulence model?" Tags="|models|numerical-modelling|turbulence|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2933" PostTypeId="2" ParentId="2911" CreationDate="2014-12-01T17:55:30.520" Score="11" Body="&lt;p&gt;Email response from Alex Jacques (Programming Support - MesoWest):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The exact interpretation can vary between data providers to MesoWest,&#xA;  but in general it refers to the amount of snow that has fallen on an&#xA;  &quot;interval board&quot;.  In several cases, stations have boards where&#xA;  snowfall is recorded, and then the board is wiped clean at set&#xA;  intervals (sometimes every 6 hours, every day, etc.).  It is a&#xA;  complementary way to measure snowfall from a storm system in addition&#xA;  to a total snow depth reading, so often snow depth and snow interval&#xA;  are paired together for stations in MesoWest.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;EDIT: Why do we need snow intervals? &lt;a href=&quot;https://what-if.xkcd.com/104/&quot; rel=&quot;nofollow&quot;&gt;https://what-if.xkcd.com/104/&lt;/a&gt; explains: as more snow falls, the existing snow on the ground gets compressed. To measure snow depth consistently, the &quot;snow board&quot; must be cleared at regular intervals.&lt;/p&gt;&#xA;" OwnerDisplayName="user967" LastEditorDisplayName="user967" LastEditDate="2016-01-03T01:57:47.893" LastActivityDate="2016-01-03T01:57:47.893" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2934" PostTypeId="1" CreationDate="2014-12-01T21:11:04.257" Score="7" ViewCount="1130" Body="&lt;p&gt;Is there a clear formula or table relating the illuminance in (lux) to status of the sky in terms of cloud cover? For example, mostly cloudy would be 2000-3000 lux.&lt;/p&gt;&#xA;" OwnerUserId="1239" LastEditorUserId="192" LastEditDate="2014-12-02T17:29:59.407" LastActivityDate="2014-12-02T17:29:59.407" Title="Relationship between illuminance and cloud cover" Tags="|meteorology|measurements|clouds|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2935" PostTypeId="2" ParentId="2931" CreationDate="2014-12-02T11:12:07.737" Score="9" Body="&lt;p&gt;According to palaeoclimatic records modelled from sediments studied at Monte dei Corvi, in the paper &lt;a href=&quot;http://adsabs.harvard.edu/abs/2014EGUGA..16.4540T&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reconstructing the temperature and salinity of the Mediterranean Sea through the Late Miocene (13 Ma - 6 Ma) prior to the Messinian Salinity Crisis&lt;/a&gt; (Alexandrina et al. 2014), that using &lt;a href=&quot;http://www.awi.de/de/forschung/nachwuchswissenschaftlerinnen/helmholtz_hochschul_nachwuchsgruppen/compound_specific_14c_analysis/organic_proxies_for_paleoclimate_reconstructions/&quot; rel=&quot;nofollow noreferrer&quot;&gt;alkenone paleothermometry&lt;/a&gt;, there was a cooling trend starting at 8.1 million years ago, developing a cold period around 7 million years ago and continuing to the Messinian Salinity Crisis (MSC) as evidenced by a disruption in marine sedimentation (and changes to the surrounded flora and desertification in the Sahara).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Research presented in the paper &lt;a href=&quot;http://adsabs.harvard.edu/abs/2014EGUGA..16.1826O&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Onset of the Messinian Salinity Crisis along the offshore Betic Range&lt;/a&gt; (Ochoa et al. 2014) suggest that tectonic processes along the offshore Betic Range in southern Spain may be a trigger for the closure (see tectonic map below for the relevant area).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/AwybH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image source: &lt;a href=&quot;http://en.wikipedia.org/wiki/Geology_of_the_Iberian_Peninsula&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The MSCis described in the paper &lt;a href=&quot;http://www.clim-past.net/10/607/2014/cp-10-607-2014.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Modelling global-scale climate impacts of the late Miocene Messinian Salinity Crisis&lt;/a&gt; (Ivanovic et al. 2014) as being the result of the influences of climatic change as observed in sedimentary strata described by Alexandrina et al. 2014 and of tectonic activity of the offshore Betic range, as detailed by Ochoa et al. 2014.  They also suggest that during the MSC, there were intermittent outflows of saline water into the Atlantic - causing disruptions to the thermohaline circulation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Dr. Iuliana Vasiliev of the University of Utrecht, suggests that one possible influence during the MSC was interactions with the closing remnants of the Paratheys Ocean, as shown in the map below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/OMlpu.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-12-02T11:12:07.737" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2936" PostTypeId="2" ParentId="2916" CreationDate="2014-12-02T15:57:58.517" Score="9" Body="&lt;p&gt;Yool &amp;amp; Fasham in &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2000GB001359/abstract&quot;&gt;An Examination of the Continental shelf pump in an open ocean general circulation model&lt;/a&gt; Global Biogeochemical Cycles Volume 15, Issue 4, pages 831–844, divide the continental shelves into 32 named regions (see Fig. 2), and give areas for each (see table 1).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The regions that are completely in the arctic ocean are:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Russian arctic shelf 1,503,000 sq. km. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Siberian arctic shelf 1,825,000 sq. km. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;North American arctic shelf 498,000 sq. km. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are three other regions that are partially in the arctic ocean, &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Iceland and Greenland shelf, North Sea shelf, and Berring Sea shelf, but looking at Fig. 2 and table 1 these seem like small contributors. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Roughly 4 million sq. km total. &lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2014-12-02T15:57:58.517" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2937" PostTypeId="2" ParentId="2934" CreationDate="2014-12-02T16:19:19.537" Score="6" Body="&lt;p&gt;I don't believe such a formula or table exists (but admittedly, I have not attempted a lit review in this subject).  Sky coverage (cloudy, mostly cloudy, etc) is a the fraction of the sky covered by clouds, not how much light penetrates to the surface.  Even with a mostly cloudy day, all it takes is one break in the clouds between the sun and your instrument to give the same illuminance as a clear sky day.  You might take a time series of illuminance obs and consider the fraction of time with clear sky readings, but this will be faulty unless you can take into account cloud motion.&lt;/p&gt;&#xA;&lt;p&gt;From the &lt;a href=&quot;http://glossary.ametsoc.org/&quot; rel=&quot;noreferrer&quot;&gt;AMS Glossary&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;cloud cover&lt;/p&gt;&#xA;&lt;p&gt;(Also called cloudiness, cloudage.) That portion of the sky cover that is attributed to clouds, usually measured in tenths or eighths of sky covered.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The term &amp;quot;partly cloudy&amp;quot;, for example, varies in interpretation but is generally around 0.3 or 0.4 to 0.6 or 0.7 cloud cover (where 0.0 is clear sky and 1.0 is overcast).&lt;/p&gt;&#xA;&lt;p&gt;The type of cloud will also vary the light transmitted.  A high cirrus or altocirrus cloud layer will transmit light to the surface, whereas a low stratocumulus overcast will only transmit a small fraction of light (note how grey and dreary a northern winter day can be under those clouds).  The fraction of light transmitted will depend on the depth of the cloud layer. The light transmitted will also be a function of time of day and day of the year, both of which determine the position of the sun.&lt;/p&gt;&#xA;&lt;p&gt;For a look into how these issues play out in a real experiment, take a look at &lt;a href=&quot;http://dx.doi.org/10.1175/1520-0450(2003)042%3C1421:CCBOAI%3E2.0.CO;2&quot; rel=&quot;noreferrer&quot;&gt;Pfister et. al. (2003)&lt;/a&gt; who look at how cloud fraction and irradiance are related over New Zealand.  I think you'll find most of the literature deals with solar irradiance, so it may help you in searches to look for that term rather than illuminance.&lt;/p&gt;&#xA;&lt;p&gt;Note that the linked Ametsoc article is free to read, as area all Ametsoc articles at least 2 years old.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;G. Pfister, R. L. McKenzie, J. B. Liley, A. Thomas, B. W. Forgan, and C. N. Long, 2003: Cloud coverage based on all-sky imaging and its impact on surface solar irradiance. &lt;em&gt;J. Appl. Meteor.&lt;/em&gt;, &lt;strong&gt;42&lt;/strong&gt;, 1421-1434. doi: &lt;a href=&quot;http://dx.doi.org/10.1175/1520-0450(2003)042%3C1421:CCBOAI%3E2.0.CO;2&quot; rel=&quot;noreferrer&quot;&gt;http://dx.doi.org/10.1175/1520-0450(2003)042&amp;lt;1421:CCBOAI&amp;gt;2.0.CO;2&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-12-02T17:17:07.350" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2938" PostTypeId="2" ParentId="2934" CreationDate="2014-12-02T17:26:39.727" Score="4" Body="&lt;p&gt;Operationally, cloud cover is determined subjectively by visual contact with the sky from the human observer (meteorologist on duty). No instruments or objective measures are used, so the two measures cannot be related in an obvious way. The unit used to describe cloud cover is called &lt;a href=&quot;http://en.wikipedia.org/wiki/Okta&quot; rel=&quot;nofollow&quot;&gt;Okta&lt;/a&gt;, and ranges from 0 (sky completely clear) to 8 (full cover). Each value has a graphical representation which can be included on synoptic weather maps for each station.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another important reason why cloud cover cannot be unambiguously related to illuminance is explained in detail in Casey's answer - different types of clouds and cloud depths may lead to different illuminance values for same values of cloud cover.&lt;/p&gt;&#xA;" OwnerUserId="192" LastActivityDate="2014-12-02T17:26:39.727" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2939" PostTypeId="2" ParentId="2932" CreationDate="2014-12-02T20:40:43.727" Score="15" Body="&lt;p&gt;The biggest difference between LES and RANS is that, contrary to LES, RANS assumes that $\overline{u'_i} = 0$ (see the &lt;a href=&quot;https://en.wikipedia.org/wiki/Reynolds-averaged_Navier%E2%80%93Stokes_equations&quot; rel=&quot;noreferrer&quot;&gt;Reynolds-averaged Navier–Stokes equations&lt;/a&gt;). In LES the filter is spatially based and acts to reduce the amplitude of the scales of motion, whereas in RANS the time filter removes ALL scales of motion with timescales less than the filter width.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would recommend reading &lt;em&gt;&lt;a href=&quot;http://tu-dresden.de/die_tu_dresden/fakultaeten/fakultaet_maschinenwesen/ism/sm/mitarbeiter/froehlich/publications/Froehlich_vonTerzi_Hybrid-LES-RANS_PAS_08.pdf&quot; rel=&quot;noreferrer&quot;&gt;Fröhlich, Jochen, and Dominic von Terzi. &quot;Hybrid LES/RANS methods for the simulation of turbulent flows.&quot; Progress in Aerospace Sciences 44.5 (2008): 349-377&lt;/a&gt;&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From that paper, specifically the section 'Structural similarity of LES and RANS equations', you can see that the equations being solved are essentially the same for LES and RANS, however, the physics are different. The main difference being that in RANS the unclosed term is a function of the turbulent kinetic energy and the turbulent dissipation rate whereas in LES the closure term is dependent on the length scale of the numerical grid. So in RANS the results are independent of the grid resolution!&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A model qualifies as an LES model if it explicitly involves in one or&#xA;  the other way the step size of the computational grid. RANS models, in&#xA;  contrast, only depend on physical quantities, including geometric&#xA;  features like the wall distance.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As far as typical processes, this figure summarizes it pretty well. DNS resolves all scales of motion, all the way down to the Kolmogorov scale. LES is next up and resolves most of the scales, with the smallest eddies being modeled. RANS is on the other end of the spectrum from DNS, where only the large-scale eddies are resolved and the remaining scales are modeled.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/9QtNo.png&quot; alt=&quot;DNS, LES, RANS&quot;&gt;&#xA;The figure above is from André Bakker's lectures: &lt;a href=&quot;http://www.bakker.org/dartmouth06/engs150/10-rans.pdf&quot; rel=&quot;noreferrer&quot;&gt;http://www.bakker.org/dartmouth06/engs150/10-rans.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;DNS: Very small scale flow (ex:turbulent boundary layers). Currently computationally intractable for most problems.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;LES: Aims to solve the computational cost that DNS poses and reveals the eddies hidden behind the mean in RANS. Good for coastal scale scale 2D simulations and possibly lab-scale 3D simulations with a highly optimized parallel code.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;RANS: It is the least computationally expensive method that is used for turbulent modeling, but it is really not very good when certain phenomena cannot be averaged, such as instabilities. Acoustic waves are also incorrectly modeled because they are inherently unsteady processes which can't be averaged, so typically modelers will crank up the turbulent and numerical viscosity to remove acoustic waves from the system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This shows the main difference between LES and RANS.&#xA;&lt;img src=&quot;https://i.stack.imgur.com/jzbbl.jpg&quot; alt=&quot;LES vs RANS&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2014-12-03T06:17:52.243" LastActivityDate="2014-12-03T06:17:52.243" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2940" PostTypeId="2" ParentId="49" CreationDate="2014-12-03T06:42:03.177" Score="12" Body="&lt;p&gt;Disclaimer: This is a partial answer given that my background is modeling of the ocean. I hope that some mantle convection modelers can complement this answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question is good but the answer is complex. The short answer is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;No, they are not the same. Simply because computationally it would not make sense.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will try my best to break it apart and make it as concise as possible. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Preface&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As many people have pointed out scales are key. The environmental fluid dynamics problems we try to solve range enormous scales. However, every single motion is described by the Navier-Stokes (NS) equation, from the simplest flow you can think of all the way to the most complex - that includes turbulence (the continuum hypothesis says that the NS equations are valid when the &lt;a href=&quot;https://en.wikipedia.org/wiki/Knudsen_number&quot; rel=&quot;nofollow noreferrer&quot;&gt;Knudsen number&lt;/a&gt; $K_n \ll 1$).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take a look at the chart below for oceanic processes alone. Temporal scales span 10 orders of magnitude, while spatial scales span 12 orders of magnitude. Presumably mantle solvers would extend the upper bounds on each of these scales.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question you ask is specifically regarding oceanic grand circulation (OGC) models and mantle convection (MC) models. So according to the chart below, out of all oceanic models, the OGC and the MC models are the closest as far as temporal scales and spatial scales go.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/OSjDM.jpg&quot; alt=&quot;temporal and spatial scales&quot;&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The complexity of the Navier-Stokes equations and the difficulty in solving them&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Navier-Stokes system can be classified as a hybrid elliptic-hyperbolic type for steady flows and a hybrid parabolic-hyperbolic type for unsteady flows (the hyperbolic character comes from the continuity equation).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where the nature of the equations say the following about each one and their respective numerical difficulties:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Hyperbolic&lt;/strong&gt; nature is associated with wave phenomena and advective transport:&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Fast waves lead to numerical stability restrictions&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Nonlinear part of NS is hyperbolic ($\mathbf{u} \cdot \nabla \mathbf{u}$), which is the part of the equation that leads to turbulence.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Possibly one of the most difficult aspect of CFD is the propagation of sharp density fronts which are hyperbolic.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Parabolic&lt;/strong&gt; nature is associated with diffusion and mass transport:&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Boundary layers are governed by parabolic phenomena and are very thin compared to the environment that drives it. Notice the large scale disparity and associated numerical difficulty.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Turbulence, can be modeled from a parabolic perspective and this typically results in stability concerns on the numerical method employed.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Elliptic&lt;/strong&gt; nature implies instantaneous propagation of information:&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;For environmental fluid dynamics, the nonhydrostatic pressure is of elliptic nature.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Although, theoretically, any disturbance propagates at infinite speed throughout the domain, numerical iteration sets a finite speed at which information can propagate.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Non-hydrostatic solvers have to invert a Poisson equation which is very computationally &#xA;expen  sive. In general, for the nonhydrostatic pressure, the 2-d problem requires the solution of a pentadiagonal, while the 3-d problem requires the solution of a&#xA;septadiagonal (7 diagonals) (not all near the main diagonal!).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Scales and numerical solvers&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So as one can see by now, solving the NS equations numerically is not a trivial matter. Numerical solvers must face concerns regarding &lt;a href=&quot;http://web.stanford.edu/class/cme306/Discussion/Discussion1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;accuracy, stability and consistency&lt;/a&gt;, which pose constraints on the timestep and grid resolution that one can employ. See &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2932/what-are-the-differences-between-an-les-sgs-model-and-a-rans-based-turbulence-mo&quot;&gt;this answer&lt;/a&gt; regarding different approaches to numerical solvers. Scales are important for numerical solvers because of the nature of the system of the NS equations (described above) and the analytical mathematical techniques available to us to transcribe those equations to computational mathematical language. As it stands, it is impossible to resolve all temporal and spatial scales, so modelers resort to specific techniques (solvers) that apply to the problem (the scales) that they are interested in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Conclusion&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From their website:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The MITgcm (MIT General Circulation Model) is a numerical model&#xA;  designed for study of the atmosphere, ocean, and climate. Its&#xA;  non-hydrostatic formulation enables it to simulate fluid phenomena&#xA;  over a wide range of scales; its adjoint capability enables it to be&#xA;  applied to parameter and state estimation problems. By employing fluid&#xA;  isomorphisms, one hydrodynamical kernel can be used to simulate flow&#xA;  in both the atmosphere and ocean.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;CitcomS is a finite element code designed to solve compressible&#xA;  thermochemical convection problems relevant to Earth's mantle.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My guess is they both use different numerical techniques to solve different versions of the Navier-Stokes equations that make the most sense given the scales of the problem that each one aims to resolve.&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-03-26T04:04:04.623" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2941" PostTypeId="2" ParentId="1027" CreationDate="2014-12-03T09:33:34.673" Score="7" Body="&lt;p&gt;As the previous responder noted, the continental crust forms a large reservoir of potassium. Much of this is in the form of feldspar. My answer primarily addresses this continental crust source.  To get to the atmosphere, argon produced from the decay of &lt;sup&gt;40&lt;/sup&gt;K in the crystal lattice first must either diffuse out of the structure or be released during mineral alteration. Argon will be released through weathering of potassium feldspar to clay minerals. This can occur in the near surface environment or at greater depth from hydrothermal alteration or by deep circulating groundwater. Depending on your perspective, this released argon is no longer 'trapped' although there will be a concentration gradient towards the atmosphere (for example there is build-up of &lt;sup&gt;40&lt;/sup&gt;Ar in the Great Artesian Basin of central Australia).  It does not necessarily take volcanic activity to release argon to the atmosphere.  To quote Graham, DW (2002) Noble Gas Isotope Geochemistry of MORBs and OIBs in Noble Gases in Geochemistry and Cosmochemistry Reviews in Mineralogy &amp;amp; Geochemistry V. 47:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Transport of [&lt;sup&gt;40&lt;/sup&gt;Ar] to the atmosphere involves volcanic degassing, hydrothermal circulation through the crust, and erosion of continental crust...&quot;&lt;/p&gt;&#xA;" OwnerUserId="1242" LastEditorUserId="725" LastEditDate="2014-12-05T07:22:00.840" LastActivityDate="2014-12-05T07:22:00.840" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2942" PostTypeId="1" AcceptedAnswerId="2943" CreationDate="2014-12-03T14:34:15.473" Score="13" ViewCount="303" Body="&lt;p&gt;At -69.184611, -68.124276 (just east of the Bugge Islands) there is a triangular ice shelf. On satellite images (as seen on Google/Bing maps) you can see it is riddled with --for lack of a clearer description-- chunks of ice that are either ribbed or smooth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/VQ4YL.jpg&quot; alt=&quot;triangular shelf&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are these chunks? And how are they formed? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think both types of chunks might be created by the glaciers flowing toward the coast; as seen at -69.214204, -67.055682 (mostly ribbed):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/fwG8g.jpg&quot; alt=&quot;ribbed chunks&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and at -69.315307, -67.625613 (mostly smooth):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/zGwSa.jpg&quot; alt=&quot;smooth chunks&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But how is there a difference between the two?&lt;/p&gt;&#xA;" OwnerUserId="1248" LastEditorUserId="6298" LastEditDate="2022-02-06T17:31:07.687" LastActivityDate="2022-02-06T17:31:07.687" Title="Glaciology: odd pattern of smooth and ribbed chunks of ice in Antartica" Tags="|glaciology|antarctica|ice-sheets|satellite-oddities|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2943" PostTypeId="2" ParentId="2942" CreationDate="2014-12-03T14:46:17.203" Score="15" Body="&lt;p&gt;What you see are ice bergs frozen into a sheet of sea ice. The &quot;chunks&quot; are the ice bergs. Ice shelves are fed by two sources, ice from the interior of the ice sheet and ice formed by compaction of snow accumulating on the shelf itself. This means that a shelf can have very different dynamic regimes. Parts of shelves where ice is mostly formed locally will tend to be smooth whereas shelves feed by ice discharging from the interior can exhibit crevassing. It is very common to have ice streams or more rapidly flowing sectors carrying ice from the interior to the shelf and the position and width of these are often determined by subglacial topography (valleys and ridges where larger flow occurs in the valleys). At the margins of such more rapid sectors velocities drop from maybe hundreds of meters per year to a few or tens of meters per year. This cases severe shearing resulting in formation of cracks/crevasses. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the ice eventually calves into the ocean as ice bergs, the ice will exhibit different patterns depending from what sectors it originates. The crevassed parts will result in the &quot;ridged&quot; features you see. Essentially, the ridges and furrows are traces of crevasse patterns. In your mid-picture you also see the calving front on the right hand side and it is evident that the ice there is heavily crevassed. It also exhibits flow striping (stripes in the direction of flow, usually perpendicular to the ice front) which indicates rapid flow.&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2014-12-03T14:46:17.203" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2944" PostTypeId="2" ParentId="2496" CreationDate="2014-12-03T14:58:54.070" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;My question is a more fundamental one, being, if this equilibrium (#11) governing the changes in oxidation states becomes more prevalent as the pressure decreases rapidly, what are the governing equations for when the magma is deeper in the earth?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My interpretation is that at the volcano being studied, the right side of equation 11 is favored at low pressure, and the left side is favored at high pressure (greater depth).  Deep magma there contains sulfide ($\ce{S^2-}$) in accordance with equation 11, rather than sulfate ($\ce{SO4^2-}$) which would involve equation 12.  So equation 11 applies to all depths being studied and equation 12 does not apply to this volcano at any depth.  &lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="725" LastEditDate="2014-12-03T18:40:31.943" LastActivityDate="2014-12-03T18:40:31.943" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2945" PostTypeId="5" CreationDate="2014-12-03T15:18:04.640" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-12-03T15:18:04.640" LastActivityDate="2014-12-03T15:18:04.640" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2946" PostTypeId="4" CreationDate="2014-12-03T15:18:04.640" Score="0" Body="A solid material whose constituents, such as atoms, molecules or ions, are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions." OwnerUserId="115" LastEditorUserId="2958" LastEditDate="2018-11-07T12:24:20.800" LastActivityDate="2018-11-07T12:24:20.800" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="2947" PostTypeId="1" AcceptedAnswerId="2948" CreationDate="2014-12-03T23:28:02.470" Score="10" ViewCount="316" Body="&lt;p&gt;I am doing a research project on &lt;a href=&quot;http://www.volcanolive.com/lamington.html&quot; rel=&quot;noreferrer&quot;&gt;Mount Lamington&lt;/a&gt; and through my research I have found that its magma has unusually high amounts of chronium and nickel. What would cause this to happen? Is there science behind it, or is it unexplained?&lt;/p&gt;&#xA;" OwnerUserId="1251" LastEditorUserId="725" LastEditDate="2014-12-05T07:19:45.803" LastActivityDate="2014-12-05T07:19:45.803" Title="Why would magma have high amounts of nickel and chromium?" Tags="|volcanology|geochemistry|volcanoes|petrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2948" PostTypeId="2" ParentId="2947" CreationDate="2014-12-04T03:45:13.730" Score="11" Body="&lt;p&gt;The current thinking according to modelling and previous observations is that the high amounts of $\ce{MgO}$, $\ce{Cr}$ and $\ce{Ni}$ is due to the magma feeding the Mt. Lamington volcano being contaminated by the nearby Papuan Ultramafic Belt (Smith, 2014; Arculus et al. 1983).  The Papuan Ultramafic Belt is, according to Lus et al. (2001), a early Neogene (Tertiary) ophiolite.  The region itself is not associated with an active Wadati-Benioff Zone (Smith, 2004).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Smith describes that the composition of the magma that fed the Mt. Lamington eruption represents part of an unusual tectonic environment, as described in part in the answer to the earlier question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2701/what-are-the-geological-mechanisms-for-sea-floor-spreading-in-the-bismarck-sea&quot;&gt;What are the geological mechanisms for sea floor spreading in the Bismarck Sea?&lt;/a&gt;.  Smith describes that the magmatic geochemistry is influenced by the variables of crustal thickness, tectonic setting and the geochemistry of the lithosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, the relationship between the tectonics of the region and magmatism of the Papuan arc environment has been described as a 'delayed melting' as a partial melting of a source that was&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;metasomatised in an earlier convergent event.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The complicated geology is shown in the image below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/j5g3D.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tectonic and geological map from &lt;a href=&quot;http://su-thermochronology.syr.edu/Research/Research_Papua-New-Guinea_RWD.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Syracuse University Department of Earth Sciences&lt;/a&gt;, the ophiolite (PUB) outcrops are in purple.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Arculus et al. 1983, 'Ophiolote contaminated andesites, trachybasalts and cognate inclusions of Mt. Lamington, Papua New Guinea: anhydrite-amphibole bearing lavas and the 1951 cumulodome', &lt;em&gt;Bulletin of Volcanology and Geothermal Research&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lus, W. et al. 2001, 'Papuan Ultramafic Belt (PUB) Ophiolite: Field Mapping, Petrology, Mineral chemistry, Geochemistry, Geochronology, And Experimental Studies Of The Metamorphic Sole', &lt;em&gt;American Geophysical Union, Fall Meeting 2001, abstract #T52D-09&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Smith, I. 'High magnesium andesites: the example of the Papuan Volcanic Arc' in Gomez-Tuena et al. (eds) 2014, 'Orogenic Andesites and Crustal Growth', &lt;em&gt;Geological Society Special Publication 385&lt;/em&gt; page 128&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-12-04T03:45:13.730" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2950" PostTypeId="1" AcceptedAnswerId="2951" CreationDate="2014-12-04T07:29:44.537" Score="13" ViewCount="39698" Body="&lt;p&gt;There are two groups of elements that are frequently mentioned when discussing incompatible trace elements. They are the high field strength elements (HFS or HFSE) and the large ion lithophile elements (LIL or LILE).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are these groups? How are they used in geochemistry and petrology?&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2016-01-22T04:51:07.180" LastActivityDate="2018-01-28T11:31:02.373" Title="What are the high field strength and large ion lithophile (HFS or HFSE &amp; LIL or LILE) elements?" Tags="|geology|volcanology|geochemistry|mineralogy|petrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2951" PostTypeId="2" ParentId="2950" CreationDate="2014-12-04T07:30:08.107" Score="12" Body="&lt;p&gt;&lt;strong&gt;First, a short introduction to incompatible elements&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth's mantle is mostly composed of the minerals olivine, pyroxene, anorthite, spinel and garnet. These minerals are made from the elements Si, Al, Fe, Mg and Ca. In the figure below I've put them in the MRFE field (Mantle Rock Forming Elements). The trace elements, the elements that occur in very low concentrations, do not form their own minerals and instead are incorporated into the crystal lattice of the common minerals. This is easy in the case elements that share the radius and charge with the major elements because they can easily fit into the crystal lattice (for example Ni in olivine, Cr in clinopyroxene).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most elements, however, plot out of the MRFE field in the figure and are considered incompatible elements. That is, in the case of mantle melting, these incompatible elements are partitioned to the magma and eventually migrate with it when it goes to form new rocks (for example basalts). Because different processes and conditions of mantle melting result in different patterns and contents of incompatible elements in the new rocks, we can learn about the mantle melting process by studying these elements in more accessible rocks (such as basalts in volcanoes).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that I am referring to incompatible elements as incompatible with respect to mantle minerals. In some crustal rocks K, Na and Ti become major elements. In that case the MRFE should be renamed CRFE (Crustal Rock Forming Elements) and expanded to include these elements as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/RXCuD.png&quot; alt=&quot;trace elements&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;HFSE and LILE&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The incompatible elements are then subdivided into two groups: the high field strength elements (HFS or HFSE) and the large ion lithophile elements (LIL or LILE).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The LIL name partly gives away why they are called like that: the LIL are indeed larger than other cations. They are lithophile in the sense that they are incompatible and usually end up enriched in the crust (also lithosphere).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The HFS are also enriched in the crust (eventually) but their name derives from their small radius compared to their high cationic charge: the z/r ratio. As a result, their bonding to nearby anions is very strong, that is - they have a high electrical field strength.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The subdivision between the two groups has been defined at z/r = 2.0, but as this is a continuous value, no strict theoretical definition of where the boundary lies can be given. Historically, the REE have been considered as LIL. In more modern times, the REE may be excluded when discussing HFS.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Why do we need the two groups?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even though both the LILE and HFSE behave in an incompatible way during mantle melting, their response to post-magmatic processes differ. The HFSE are usually immobile: that is, they are mostly resistant to metamorphism and hydrothermal alteration. On the other hand, the LILE are fluid-mobile and hydrothermal alteration may change their contents in the studied rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fresh rocks are a scarce luxury and many rocks that we study have experienced some kind of alteration. Because HFSE are resistant to these processes, their contents are likely to be representative of the original rock. This is extremely important: it is possible to look at a rock beyond the altered mineral composition and the modified major element contents. The LIL can teach us the opposite - we can learn about the alteration processes. If we do find fresh rocks and we find anomalies in the LIL systematics, we can learn about hydrothermal processes that occurred in the mantle that would otherwise not be able to see.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What about hexavalent cations?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One would think that hexavalent cations such as Mo&lt;sup&gt;6+&lt;/sup&gt;, Cr&lt;sup&gt;6+&lt;/sup&gt;, V&lt;sup&gt;6+&lt;/sup&gt; and U&lt;sup&gt;6+&lt;/sup&gt; should also appear in the figure as cations with an even more HFS character. However, when in the hexavalent state they form anionic complexes and do not behave like the cations in the figure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Further reading&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://ocw.mit.edu/courses/earth-atmospheric-and-planetary-sciences/12-479-trace-element-geochemistry-spring-2013/lecture-notes/MIT12_479S13_lec5.pdf&quot; rel=&quot;noreferrer&quot;&gt;MIT OpenCourseWare - Trace-Element Geochemistry&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.science.marshall.edu/elshazly/Igmet/trace%20elements.doc&quot; rel=&quot;noreferrer&quot;&gt;The Use of Trace Elements in Igneous Petrology&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;About the figure&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Inspired by figure 2.2 from &lt;em&gt;Ore Deposit Geology / Scott&lt;/em&gt;. Data for figure from &lt;a href=&quot;http://www.gly.uga.edu/railsback/PT.html&quot; rel=&quot;noreferrer&quot;&gt;An Earth Scientist's Periodic Table of the Elements and Their Ions&lt;/a&gt; (also &lt;a href=&quot;https://doi.org/10.1130/G19542.1&quot; rel=&quot;noreferrer&quot;&gt;doi&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2018-01-28T11:31:02.373" LastActivityDate="2018-01-28T11:31:02.373" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2952" PostTypeId="1" CreationDate="2014-12-04T08:32:14.547" Score="-6" ViewCount="246" Body="&lt;p&gt;In the Northern hemisphere the rotation of the Earth determines a counter-clockwise spin on matter. Weather, ocean currents all are related in that spin. I wonder if my snail fossils preserve the original 'spin' of the earth's rotation and have a reserved momentum. Would that be useful in analyzing gravity/spin at that time period?&lt;/p&gt;&#xA;" OwnerUserId="621" LastActivityDate="2014-12-11T08:00:20.580" Title="Is angular momentum preserved in a gastropod fossil?" Tags="|geophysics|geology|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="2954" PostTypeId="2" ParentId="2952" CreationDate="2014-12-04T09:42:25.993" Score="10" Body="&lt;p&gt;If you're talking about the chirality of the shell, it has been shown that it was the expression of the &lt;em&gt;dpp&lt;/em&gt; gene (&lt;strong&gt;Shimizu et al. 2013&lt;/strong&gt;).&lt;br&gt;&#xA;More trivially, if chirality had anything to do with the Coriolis effect, all gastropods from the Southern Hemisphere would be sinistral and all the ones from the Northern hemisphere would be dextral. Which is not the case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shimizu et al. 2013. &lt;a href=&quot;http://www.evodevojournal.com/content/4/1/15/abstract&quot;&gt;Left-right asymmetric expression of dpp in the mantle of gastropods correlates with asymmetric shell coiling.&lt;/a&gt; EvoDevo, 4(15).&lt;/p&gt;&#xA;" OwnerUserId="87" LastActivityDate="2014-12-04T09:42:25.993" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2955" PostTypeId="2" ParentId="2419" CreationDate="2014-12-05T13:06:19.700" Score="8" Body="&lt;p&gt;This is a very complex issue, and therefore I'm not entirely convinced I am qualified to answer that, considering how little I understand chemistry, but I'll give it a try.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Flux of CO&lt;sub&gt;2&lt;/sub&gt; can be expressed as follows (see e. g. &lt;strong&gt;Wanninkhof et al. 2009&lt;/strong&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$F = kK_0(p_{\mathrm{CO}_2sea} - p_{\mathrm{CO}_2air})$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By convention a negative $F$ means a flux from the atmosphere to the ocean.&lt;br&gt;&#xA;$k$ is the transfert velocity and $K_0$ is the solubility which indeed decreases with temperature, as you noted.&lt;br&gt;&#xA;$p_{\mathrm{CO}_2sea}$ and $p_{\mathrm{CO}_2air}$ are respectively the partial pressure of CO&lt;sub&gt;2&lt;/sub&gt; in the sea and in the atmosphere.&lt;br&gt;&#xA;Now, with $T$ increasing, $K_0$ (and also $k$ I believe)  decreases, but, as long as the partial pressure of CO&lt;sub&gt;2&lt;/sub&gt; is larger in the atmosphere than in the ocean there still is a flux toward the ocean.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So worst case scenario, increasing temperature slows down the absorption of CO&lt;sub&gt;2&lt;/sub&gt; by the ocean but does not negate it. However of course, if the temperature increase to begin with, it is because $p_{\mathrm{CO}_2air}$ is increasing, so this is a bit of a moot point anyway.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as the ocean buffer goes, we're talking here of an uptake of ca. 2 Pg (i.e. $2\times10^{15}$g) of carbon dioxide per year (the preindustrial uptake being ca. 0.5 Pg according to &lt;strong&gt;Takahashi et al. 2009&lt;/strong&gt;), which is too much to be buffered. For comparison, phytoplankton net primary productivity is ca. 50 Pg of fixed carbon per year (&lt;strong&gt;Falkowski et al. 1998&lt;/strong&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Falkowski, P. G., Barber, R. T., Smetacek, V., 1998. &lt;a href=&quot;http://dx.doi.org/10.1126/science.281.5374.200&quot; rel=&quot;nofollow&quot;&gt;Biogeochemical Controls and Feedbacks on Ocean Primary Production&lt;/a&gt;. Science, 281: 200-207.&lt;br&gt;&#xA;Takahashi, T., et al. 2009. &lt;a href=&quot;http://dx.doi.org/10.1016/j.dsr2.2008.12.009&quot; rel=&quot;nofollow&quot;&gt;Climatological mean and decadal change in surface ocean pCO&lt;sub&gt;2&lt;/sub&gt;, and net sea–air CO&lt;sub&gt;2&lt;/sub&gt; ﬂux over the global oceans&lt;/a&gt;. Deep Sea Research II, 56: 554-577.&lt;br&gt;&#xA;Wanninkhof, R., et al. 2009. &lt;a href=&quot;http://www-pord.ucsd.edu/~sgille/highlat/bams_paper2/wanninkhof%20arms%202009.pdf&quot; rel=&quot;nofollow&quot;&gt;Advances in Quantifying&#xA;Air-Sea Gas Exchange and Environmental Forcing&lt;/a&gt;. Annual Review of Marine Science, 1: 213-244.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="725" LastEditDate="2014-12-12T07:33:26.260" LastActivityDate="2014-12-12T07:33:26.260" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2956" PostTypeId="1" AcceptedAnswerId="2969" CreationDate="2014-12-05T13:21:06.663" Score="22" ViewCount="7278" Body="&lt;p&gt;We know we cannot live without salt, but an investigation into the origins of ocean's salt leads one to believe that this issue is not fully resolved yet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What geological phenomenon caused the earth to contain so much of salt? I see questions on SE that ask about the origin of earth's water. In a similar vein did an extraterrestrial body &quot;dump&quot; salt on earth or is salt native to Earth?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It appears from these links that Jupiter's Moon Europa does contain a salty ocean - &#xA;&lt;a href=&quot;http://www.space.com/20078-jupiter-moon-europa-ocean-surface.html&quot;&gt;http://www.space.com/20078-jupiter-moon-europa-ocean-surface.html&lt;/a&gt; and &lt;a href=&quot;http://www.planetary.brown.edu/pdfs/2440.pdf&quot;&gt;http://www.planetary.brown.edu/pdfs/2440.pdf&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From a geochronology perspective what causes a planet to &quot;develop&quot; salt concentrations ? &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorUserId="20" LastEditDate="2014-12-12T01:27:35.063" LastActivityDate="2017-02-08T09:58:44.600" Title="What is the origin of the ocean's salt?" Tags="|geology|ocean|geochemistry|geochronology|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2957" PostTypeId="5" CreationDate="2014-12-05T14:03:19.137" Score="0" Body="&lt;p&gt;Please include as much relevant detail as possible when asking for help in identifying objects such as clouds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that &lt;a href=&quot;https://earthscience.meta.stackexchange.com/q/1768/6&quot;&gt;rock identification requests are off-topic on Earth Science Stack Exchange&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="6" LastEditDate="2019-07-30T09:07:22.127" LastActivityDate="2019-07-30T09:07:22.127" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="2958" PostTypeId="4" CreationDate="2014-12-05T14:03:19.137" Score="0" Body="For help in identifying objects such as clouds. Please include as many details as possible. DO NOT ASK ROCK IDENTIFICATION REQUESTS — rock identification requests are off topic." OwnerUserId="87" LastEditorUserId="6" LastEditDate="2019-07-30T09:07:22.127" LastActivityDate="2019-07-30T09:07:22.127" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="2959" PostTypeId="1" AcceptedAnswerId="2968" CreationDate="2014-12-05T17:34:02.007" Score="12" ViewCount="1221" Body="&lt;p&gt;I see maps like &lt;a href=&quot;http://weather.org/radar.htm&quot;&gt;this&lt;/a&gt; one all the time online and in the news. A moving map that shows clouds and stuff moving around with time. Where do they get the data from? Is it from a single source location or multiple locations? Also, is it free? Is it open for public access?&lt;/p&gt;&#xA;" OwnerUserId="1255" LastEditorUserId="192" LastEditDate="2014-12-05T18:50:29.293" LastActivityDate="2019-04-29T16:40:23.773" Title="From where do weather radar maps get their data?" Tags="|meteorology|measurements|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2961" PostTypeId="2" ParentId="2959" CreationDate="2014-12-05T18:28:44.973" Score="8" Body="&lt;p&gt;The clouds that are shown on a radar map are a satellite picture that has been superimposed onto the map.&#xA;&lt;p&gt;&#xA;The radar data is from various National Weather Service weather radar stations across the country. The satellite cloud data is provided NASA.&#xA;&lt;p&gt;&#xA;The radar and cloud pictures for the USA are free and available to the public through &lt;a href=&quot;http://www.intellicast.com/National/Satellite/Infrared.aspx&quot; rel=&quot;nofollow&quot; title=&quot;Intellicast&quot;&gt;Intellicast&lt;/a&gt; and the &lt;a href=&quot;http://www.weather.gov/&quot; rel=&quot;nofollow&quot; title=&quot;NWS&quot;&gt;NWS&lt;/a&gt; (National Weather Service) websites. Both of these sites will be helpful to you in learning more about both of these features/services.&#xA;&lt;p&gt;&lt;/p&gt;&#xA;" OwnerUserId="342" LastEditorUserId="39" LastEditDate="2014-12-07T08:12:31.433" LastActivityDate="2014-12-07T08:12:31.433" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="2962" PostTypeId="2" ParentId="2" CreationDate="2014-12-05T18:57:43.783" Score="2" Body="&lt;p&gt;NOAA flies routine dropsonde missions into tropical convection if there is anticipated threat to land.  You can find information about these missions in the routine NHC updates for each storm.  This data is used in estimation of hurricane intensity and some of the models assimilate this data to improve storm track and intensity forecasts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can learn more about NOAA's hurricane hunters &lt;a href=&quot;http://flightscience.noaa.gov/&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Dropsonde missions over the continental US are problematic.  The &lt;a href=&quot;http://www.eol.ucar.edu/field_projects/mpex&quot; rel=&quot;nofollow&quot;&gt;mesoscale predictability experiment (MPEX)&lt;/a&gt; use dropsondes to determine if better upper air observations could improve predictability in the mesoscale.  One big issue they had is restrictions in where they could drop from the FAA.  They had to provide notice well in advance of the flights and could only conduct missions during certain time windows.  This provided big restrictions in dropsonde missions and would probably make it unsuitable for drops into deep convection (though one might argue with air traffic routing around such convection, that would make drops feasible from an FAA standpoint).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There were some recent talks about MPEX at the &lt;a href=&quot;https://ams.confex.com/ams/27SLS/webprogram/start.html&quot; rel=&quot;nofollow&quot;&gt;27th Conference on Severe Local&lt;/a&gt; Storms in &lt;a href=&quot;https://ams.confex.com/ams/27SLS/webprogram/Session37655.html&quot; rel=&quot;nofollow&quot;&gt;a session about MPEX&lt;/a&gt;.  In particular, a &lt;a href=&quot;https://ams.confex.com/ams/27SLS/videogateway.cgi/id/28364?recordingid=28364&quot; rel=&quot;nofollow&quot;&gt;talk by Morris Weisman (video)&lt;/a&gt; talks a bit about the dropsonde missions.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;From another perspective was the &lt;a href=&quot;http://www.eol.ucar.edu/field_projects/dc3&quot; rel=&quot;nofollow&quot;&gt;DC3&lt;/a&gt; project, which I provided nowcasting in support of aircraft operations.  This project didn't use dropsondes, but instead used aircraft in vertical flight profiles to collect observations from near-surface to tropopause levels.  These profiles were in the vicinity of deep convection, but not within.  This project was primarily interested in how the chemical composition of near-surface air was modified by convection and then transported in upper air outflow.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These aircraft were not dropping dropsondes but I'm not confident a UAV would have been able to fly too much closer to convection to drop into the storms.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;In summary, maritime dropsondes are common for getting in-situ measurements of tropical convection, but for continental applications FAA restrictions on dropping things from airplanes makes routine dropsonde missions unfeasible (and I'm assuming these would be done by UAVs as getting NSF aircraft assets to do this would be restricted to short term experiments and not routine operational missions).  &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-12-05T18:57:43.783" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2963" PostTypeId="1" AcceptedAnswerId="2973" CreationDate="2014-12-06T01:19:17.013" Score="9" ViewCount="215" Body="&lt;p&gt;Last winter, several areas in the US and Canada were hit by a &quot;polar vortex.&quot; I happen to live in one of those areas and was amazed how much the temperature seemed to change so suddenly just because a bunch of &quot;air&quot; had changed locations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why can air temperature influence surface temperatures so radically? &lt;/p&gt;&#xA;" OwnerUserId="1260" LastEditorUserId="64" LastEditDate="2014-12-07T04:03:24.813" LastActivityDate="2014-12-07T04:03:24.813" Title="Why does air seem to affect local surface temperatures so much?" Tags="|meteorology|temperature|wind|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2964" PostTypeId="1" CreationDate="2014-12-06T03:30:37.287" Score="8" ViewCount="175" Body="&lt;p&gt;The &lt;a href=&quot;http://en.wikipedia.org/wiki/Great_Oxygenation_Event&quot;&gt;Great Oxygenation Event&lt;/a&gt; (sometimes called the Great Oxidation Event (GOE), as in the journal &lt;a href=&quot;http://www.nature.com/nature/journal/v451/n7176/fig_tab/nature06587_F1.html&quot;&gt;Nature&lt;/a&gt;) occurred around 2.2 to 2.45 billion years ago (Frei et al. 2009). However, in the article &lt;a href=&quot;http://archenv.geo.uu.nl/pdf/Anbar%20et%20al%202007%20Science%20Whiff%20Oxygen.pdf&quot;&gt;A Whiff of Oxygen Before the Great Oxidation Event?&lt;/a&gt; (Anbar et al. 2007) and in &lt;a href=&quot;http://www.nature.com/nature/journal/v451/n7176/full/nature06587.html&quot;&gt;The rise of atmospheric oxygen&lt;/a&gt; (Kump, 2008) where it is hypothesised that through chemostratigraphy, there was a small amount of oxygen before the GOE.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is disputed in the later article &lt;a href=&quot;http://gsabulletin.gsapubs.org/content/126/9-10/1245.abstract&quot;&gt;Hematite replacement of iron-bearing precursor sediments in the 3.46-b.y.-old Marble Bar Chert, Pilbara craton, Australia&lt;/a&gt; (Rasmussen et al. 2014), who state that the hematite found in banded chert of Marble Bar (and environs) are mistakenly interpreted as being evidence of a oxygenated ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is there conclusive evidence to refute the presence of an earlier oceanic/atmospheric oxygenation prior to the GOE?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Additional references&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Frei et al. 2009, &lt;a href=&quot;http://www.nature.com/nature/journal/v461/n7261/full/nature08266.html&quot;&gt;Fluctuations in Precambrian atmospheric oxygenation recorded by chromium isotopes&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2019-08-05T10:23:36.787" Title="Is there conclusive evidence to refute an earlier oxygenation of the Earth's atmosphere?" Tags="|atmosphere|paleoclimatology|great-oxidation-event|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2965" PostTypeId="1" AcceptedAnswerId="4435" CreationDate="2014-12-06T03:54:38.740" Score="11" ViewCount="457" Body="&lt;p&gt;Using chromium isotopes geochemistry, Frei et al. 2009, describe in the article &lt;a href=&quot;http://www.nature.com/nature/journal/v461/n7261/abs/nature08266.html&quot;&gt;Fluctuations in Precambrian atmospheric oxygenation recorded by chromium isotopes&lt;/a&gt; that after the Great Oxidation Event (2.2-2.45 billion years ago), there was a precipitous decline in atmospheric oxygen at about 1.88 billion years ago, to have &quot;all but disappeared&quot; as described by Lyons and Reinhard 2009 in the article &lt;a href=&quot;http://www.nature.com/nature/journal/v461/n7261/full/461179a.html#B2&quot;&gt;Early Earth: Oxygen for heavy-metal fans&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What evidence is there for a the drop in atmospheric oxygen approximately 1.9 billion years ago?&lt;/strong&gt; &lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="725" LastEditDate="2014-12-06T08:26:35.607" LastActivityDate="2015-04-20T08:41:08.000" Title="What caused a fall in atmospheric oxygen about 1.9 billion years ago?" Tags="|atmosphere|earth-history|precambrian|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2966" PostTypeId="1" CreationDate="2014-12-06T04:46:33.867" Score="11" ViewCount="18300" Body="&lt;p&gt;I am looking for locations/places/countries that only have one season.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By seasons, I mean a large varying change in temperature and precipitation caused by the climate in the region. I am not looking for abnormal weather.&lt;/p&gt;&#xA;" OwnerUserId="1263" LastEditorUserId="11908" LastEditDate="2019-01-18T05:13:29.847" LastActivityDate="2019-01-20T12:57:15.630" Title="Are there locations on Earth that only have one season?" Tags="|climate|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="2967" PostTypeId="2" ParentId="1065" CreationDate="2014-12-06T11:56:08.293" Score="4" Body="&lt;p&gt;Though you have divided your question up into 6 parts, I am combining the information in the answer, as they all link together.  Also, as can be seen in the reference list (below), the resources come from the same primary author, but from different aspects of his studies of this phenomena (these are all paywalled, so university access would be required - but I'll paraphrase the main points).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Firstly, a bit of terminology, a Nor'wester are storm gusts between 11 ms$^{-1}$ and 42 ms$^{-1}$, above which are referred to locally as being 'tornadoes' (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S016980950900324X&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;).  These are collectively known as Severe Low Convective Storms (SLCS) by Yamana et al. (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/joc.3460/abstract&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt;),(&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S016980950900324X&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;),(&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2006GL026823/abstract&quot; rel=&quot;nofollow&quot;&gt;3&lt;/a&gt;). The main areas affected are across Bangladesh and north-east India (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2006GL026823/abstract&quot; rel=&quot;nofollow&quot;&gt;3&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;SLCS generally seasonal, usually occurring during the pre-monsoon months of March to May, peaking in April, usually in the evenings (as you have observed). Although rare, SLCS can actually occur at any time of the day and at any time of the year (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S016980950900324X&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;). Records over several years do not show any particular obvious trend in occurrence and frequency of events that occur each year - though they average at around 145 occurring each year (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S016980950900324X&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yamane et al. 2010 (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S016980950900324X&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;) note that the most frequent occurrence is in the Dhaka district (north-central Bangladesh) and trends in a northerly direction during the pre-monsoon.  However, the authors caution this observation as being the result of the amount of people recording these occurrences in other districts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yamana and Hayashi (2006) (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2006GL026823/abstract&quot; rel=&quot;nofollow&quot;&gt;3&lt;/a&gt;) explain that the SLCS are a result of regional atmospheric thermal instability, where the convective available potential energy (CAPE) is high (greater than 2000 Jkg$^{-1}$) and the shear is moderate (greater than 10 ms$^{-1}$, and that the phenomena also coincides with severe local storms across the Indian Subcontinent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yamana et al. (2012) (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/joc.3460/abstract&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt;) elaborates further on what causes the atmospheric thermal instability, with a synoptic analysis of a SLCS, describing the phenomena as a confluence of  (note, the authors use AGL = 'above ground level' for the following information):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Moisture inflow (increase in humidity) from the Bay of Bengal, enhanced by a south-west wind intensification at 950 hPa (approx. 500 m AGL). This increases the amount of water vapour available.&lt;/li&gt;&#xA;&lt;li&gt;A temperature increase, due to westerly winds, across the region at 800 hPa (approx. 2 km AGL), leading to&lt;/li&gt;&#xA;&lt;li&gt;A trough leading to an enhancement of cold advection at 550 hPa (approx. 5 km AGL) from the north west.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;This, in part, gives a reason for its name and confirms your 6th point, that it blows in from the north-west. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/joc.3460/abstract&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt;) Yamana Y. et al. 2012, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/joc.3460/abstract&quot; rel=&quot;nofollow&quot;&gt;Synoptic situations of severe local convective storms during the pre-monsoon season in Bangladesh&lt;/a&gt;, International Journal of Climatology&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S016980950900324X&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;) Yamana Y. et al. 2010, &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S016980950900324X&quot; rel=&quot;nofollow&quot;&gt;Severe local convective storms in Bangladesh: Part I. Climatology&lt;/a&gt;, Atmospheric Research&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2006GL026823/abstract&quot; rel=&quot;nofollow&quot;&gt;3&lt;/a&gt;) Yamana Y. and Hayashi, T. 2006, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2006GL026823/abstract&quot; rel=&quot;nofollow&quot;&gt;Evaluation of environmental conditions for the formation of severe local storms across the Indian subcontinent&lt;/a&gt;, Geophysical Research Letters&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-12-06T11:56:08.293" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2968" PostTypeId="2" ParentId="2959" CreationDate="2014-12-06T13:06:59.967" Score="13" Body="&lt;p&gt;Images showing clouds mostly come from geostationary satellites. Geostationary satellites are at an altitude of about 36000 km, which allows them to monitor the same area of the Earth continuously. They stay in place relative to the Earth's surface above the equator thanks to balance between gravitational and centrifugal force. There are a few such satellites designated to operational weather forecasting, notably:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Geostationary_Operational_Environmental_Satellite&quot; rel=&quot;nofollow noreferrer&quot;&gt;GOES-East &amp;amp; GOES-West&lt;/a&gt; operated by &lt;a href=&quot;http://www.noaa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Meteosat&quot; rel=&quot;nofollow noreferrer&quot;&gt;Meteosat-7,-8,-9,-10&lt;/a&gt; operated by &lt;a href=&quot;http://www.eumetsat.int&quot; rel=&quot;nofollow noreferrer&quot;&gt;EUMETSAT&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Multi-Functional_Transport_Satellite&quot; rel=&quot;nofollow noreferrer&quot;&gt;MTSAT&lt;/a&gt; operated by JMA (Japan)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;These satellites contain passive remote sensing instruments measuring incoming radiation in a number of channels, mostly visible and infrared. Visible is only available during the day, while infrared is available all the time. Radiation is captured on lines of sensors by scanning the view, which generally takes a few minutes to complete. Geostationary satellites are unable to capture polar regions above a certain latitude, because of the angle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to geostationary satellites, there are polar orbiting weather satellites:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/NOAA-19&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA-18,-19&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/MetOp&quot; rel=&quot;nofollow noreferrer&quot;&gt;MetOp-A,-B&lt;/a&gt; (EUMETSAT)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Polar satellites fly much lower (~800 km) and cannot provide continuous global coverage, only swathes along their orbits.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All of this data can be used in the assimilation (initialization) process of weather forecasting models. In turn, one can produce images of cloud cover from the output of the models, see e.g. &lt;a href=&quot;http://www.wetterzentrale.de/topkarten/&quot; rel=&quot;nofollow noreferrer&quot;&gt;wettercentrale.de&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NASA operates mostly research satellites, not so much operational weather satellites, although they do cooperate with NOAA on some of the missions. In Europe, the counterpart is ESA, who run some satellites on their own (e.g. Sentinel and in the past Envisat and ERS-1,-2) and cooperate with EUMETSAT.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data from satellites is downlinked to communication centers (sometimes routed via other communication satellites), where it is processed by various algorithms into products (data files). Product files can be downloaded over the Internet by national weather services or are made available publicly to anyone (all data from NASA satellites is public - see e.g. &lt;a href=&quot;http://gcmd.nasa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA Global Change Master Directory&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Weather radars are generally located on the ground. They operate by sending short pulses of microwave radiation and measuring the reflected (backscattered) radiation from water/ice droplets. As the microwave radiation has relatively large wavelength (on the order of one millimeter), it is not very sensitive to cloud droplets, and you can see mostly bands of precipitation. Weather radars are operated locally by national weather services. You need roughly one per 250 km to get a good coverage. As with data from weather satellites, they are very important in assimilation of numerical weather prediction models. There are also spaceborne radars, e.g. DPR on &lt;a href=&quot;http://www.nasa.gov/mission_pages/GPM/main/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;GPM Core Observatory&lt;/a&gt;, &lt;a href=&quot;http://trmm.gsfc.nasa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;TRMM&lt;/a&gt;, or &lt;a href=&quot;http://www.cloudsat.cira.colostate.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CloudSat&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="1265" LastEditorUserId="6031" LastEditDate="2019-04-29T16:40:23.773" LastActivityDate="2019-04-29T16:40:23.773" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="2969" PostTypeId="2" ParentId="2956" CreationDate="2014-12-06T17:30:43.613" Score="16" Body="&lt;p&gt;As one could imagine, there is a considerable amount of conjecture as to precisely Earth got its salt content.  Ultimately, it came from the primordial planetary nebula and concentrations of the ions involved would have come from the various ingredients of the accretionary process.  This answer focuses on how salt may have first formed, hence accumulated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ocean salinity is &lt;em&gt;almost&lt;/em&gt; a chicken and egg situation - was their salt before the first waters or vice versa?  According to current research, the latter appears to be true, especially in the case of the dominant $\ce{NaCl}$ species.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Knauth (2005) (&lt;a href=&quot;http://www.springer.com/earth+sciences+and+geography/geology/book/978-3-540-66193-1&quot;&gt;2&lt;/a&gt;) contends that $\ce{Cl-}$ ions were outgassed through volcanic eruptions in the form of $\ce{HCl}$ and $\ce{Na+}$ were theorised to have been leached out of rocks (&lt;a href=&quot;http://www.nature.com/nature/journal/v431/n7009/full/nature02973.html&quot;&gt;1&lt;/a&gt;).  The exact amount of these ions and salt content are not entirely known (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0031018204005905&quot;&gt;3&lt;/a&gt;), but the process may have started even as far back as the Hadean, and certainly in the Archean (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0031018204005905&quot;&gt;3&lt;/a&gt;) and the early water bodies were believed to have been up to twice as saline as today (&lt;a href=&quot;http://www.springer.com/earth+sciences+and+geography/geology/book/978-3-540-66193-1&quot;&gt;2&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of halite deposits, this requires evaporation of a brine, which according to Knauth (2005) (&lt;a href=&quot;http://www.springer.com/earth+sciences+and+geography/geology/book/978-3-540-66193-1&quot;&gt;2&lt;/a&gt;) and Sleep (2010) (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0031018204005905&quot;&gt;3&lt;/a&gt;) required large enough continental masses to be able to enclose water bodies - the amount of this occurring in conjectural for Earth, as the halite produced would be unlikely to be preserved (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0031018204005905&quot;&gt;3&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Knauth (2005) (&lt;a href=&quot;http://www.springer.com/earth+sciences+and+geography/geology/book/978-3-540-66193-1&quot;&gt;2&lt;/a&gt;) expanded on the implications of this for other worlds with:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Inasmuch as chlorine is a common element throughout the galaxy and follows the water during atmospheric outgassing, it is likely that early oceans on other worlds are also probably so saline that evolution beyond the microbial stage is inhibited unless long-lived continental cratons develop.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Partly suggesting that the formation of salt is possible on any world - such as the salt found in Martian sediments, as per the article &lt;a href=&quot;http://www.nature.com/nature/journal/v431/n7009/full/nature02973.html&quot;&gt;Magnesium sulphate salts and the history of water on Mars&lt;/a&gt; (Vaniman et al. 2004).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.nature.com/nature/journal/v431/n7009/full/nature02973.html&quot;&gt;1&lt;/a&gt;) Einsele, G. 1992 &lt;a href=&quot;http://www.springer.com/earth+sciences+and+geography/geology/book/978-3-540-66193-1&quot;&gt;Sedimentary Basins: Evolution, Facies, and Sediment Budget&lt;/a&gt; (Book)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.springer.com/earth+sciences+and+geography/geology/book/978-3-540-66193-1&quot;&gt;2&lt;/a&gt;) Knauth, L.P. 2005 &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0031018204005905&quot;&gt;Temperature and salinity history of the Precambrian ocean: implications for the course of microbial evolution&lt;/a&gt; Palaeogeography, Palaeoclimatology, Palaeoecology&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0031018204005905&quot;&gt;3&lt;/a&gt;) Sleep, N. 2010, &lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2869525/&quot;&gt;The Hadean-Archaean Environment&lt;/a&gt; Cold Spring Harbor Perspectives in Biology&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-12-06T17:45:35.633" LastActivityDate="2014-12-06T17:45:35.633" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2970" PostTypeId="1" AcceptedAnswerId="2971" CreationDate="2014-12-06T20:52:07.137" Score="41" ViewCount="8693" Body="&lt;p&gt;While reading about the ghost ship &lt;a href=&quot;http://en.wikipedia.org/wiki/Jian_Seng&quot;&gt;Jiang Seng&lt;/a&gt; I noticed that Wikipedia claimed it was drifting in uncharted waters in the Gulf of Carpentaria. I tried to find a primary source referencing uncharted waters but couldn't find any so this may just be one editor's penchant for artistic license.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regardless it got me thinking: &lt;strong&gt;are there any oceans or perhaps other parts of the world that can still be called uncharted&lt;/strong&gt;? Or has satellite navigation and imaging given us a complete picture of our globe?&lt;/p&gt;&#xA;" OwnerUserId="1268" LastEditorDisplayName="user12525" LastEditDate="2019-04-15T14:51:33.990" LastActivityDate="2019-04-15T14:51:33.990" Title="Are there any uncharted waters left on earth?" Tags="|oceanography|satellites|" AnswerCount="4" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="2971" PostTypeId="2" ParentId="2970" CreationDate="2014-12-06T21:29:08.560" Score="34" Body="&lt;p&gt;There are many &quot;uncharted waters&quot;.  Nautical charts have information about water depths, dangers to navigation, aids to navigation, anchorages, and other features.  You can see here what might be included in a nautical chart: &lt;a href=&quot;http://www.nauticalcharts.noaa.gov/mcd/chart1/ChartNo1.pdf&quot; rel=&quot;noreferrer&quot;&gt;U.S. Chart No. 1&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The area in question is a shallow sea... so boats of different sizes may or may not be able to take certain routes depending on tides etc.  Thus a nautical chart is important in these types of regions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes satellites have mapped the world... and coastline is well defined.   You can even learn about underwater depths using satellite instrumentation that detects gravity (e.g. CryoSat2) as discussed here: &lt;a href=&quot;http://www.dnaindia.com/scitech/report-global-seafloor-map-reveals-uncharted-sea-mountains-stunning-details-of-earth-s-oceans-2023234&quot; rel=&quot;noreferrer&quot;&gt;Global seafloor map reveals uncharted sea mountains, stunning details of Earth's oceans&lt;/a&gt; which discusses recent measurements of the seafloor from space.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;University of Sydney geophysicist Dietmar Müller said about 71% of the Earth's surface is covered by water and roughly 90% of the seafloor is uncharted by survey ships that employ acoustic beams to map the depths. ... Müller said the conclusions the [satellite] researchers made about seabed topography may be less accurate than acoustic beam methods employed by ships.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and the article &lt;a href=&quot;http://www.universetoday.com/115302/gravitys-magic-new-seafloor-map-shows-earths-uncharted-depths/&quot; rel=&quot;noreferrer&quot;&gt;Gravity’s Magic: New Seafloor Map Shows Earth’s Uncharted Depths&lt;/a&gt; says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The effect of the slight increase in gravity caused by the mass of rock in an undersea mountain is to attract a mound of water several meters high over the seamount. Deep ocean trenches have the reverse effect,” ESA wrote in a statement.  “These features can only be detected by using radar altimetry from space.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="6093" LastEditDate="2016-09-23T13:16:26.063" LastActivityDate="2016-09-23T13:16:26.063" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2972" PostTypeId="2" ParentId="2236" CreationDate="2014-12-07T00:40:03.140" Score="9" Body="&lt;p&gt;This is covered in an episode of the National Geographic TV series Aftermath called &lt;a href=&quot;https://en.wikipedia.org/wiki/Aftermath_%28TV_series%29#When_the_Earth_Stops_Spinning&quot; rel=&quot;nofollow&quot;&gt;&quot;When The Earth Stops Spinning&quot;&lt;/a&gt;.  It's also covered by &lt;a href=&quot;http://www.esri.com/news/arcuser/0610/nospin.html&quot; rel=&quot;nofollow&quot;&gt;&quot;If the Earth Stood Still: Modeling the absence of centrifugal force&quot; by Witold Fraczek&lt;/a&gt; of Ersi, a GIS software company.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth is not round, but bulges at the equator.  &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth#Shape&quot; rel=&quot;nofollow&quot;&gt;The diameter at the equator is 43km more than pole-to-pole&lt;/a&gt;.  Without the Earth's spin to force the oceans &quot;uphill&quot; at the equator, they would flow &quot;downhill&quot; towards the poles.  Since the oceans are no where near as deep as 43km (&lt;a href=&quot;https://en.wikipedia.org/wiki/Mariana_Trench&quot; rel=&quot;nofollow&quot;&gt;the deepest part, Mariana Trench, is only 11km&lt;/a&gt;), the equator would be completely dry and the poles likely flooded.  Aftermath depicts an Earth with two polar oceans and a strip of dry land at the equator.  Most of North America, Europe, Northern Asia, Argentina and Antarctica are under water.  &lt;a href=&quot;http://www.esri.com/news/arcuser/0610/nospin-video.html&quot; rel=&quot;nofollow&quot;&gt;Here's a timelapse video of that process&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Worse, the atmosphere acts like a fluid, too.  It was also being held in place &quot;uphill&quot; at the poles.  It also begins to thin out around the equator, thinner than on Mt Everest.  Most of the world is either under water, or too high up for us to breathe.  Humanity is left with a thin band of habitable land at the edge of the polar oceans, with some of the lowlands of the newly dry Pacific Basin also being habitable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Doesn't matter, because with no spin a day on Earth is six months long.  Baked during the &quot;day&quot; and frozen during the &quot;night&quot;, it's not a pleasant place for people.&lt;/p&gt;&#xA;" OwnerUserId="955" LastEditorUserId="955" LastEditDate="2015-08-11T23:27:42.843" LastActivityDate="2015-08-11T23:27:42.843" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="2973" PostTypeId="2" ParentId="2963" CreationDate="2014-12-07T04:02:36.687" Score="7" Body="&lt;p&gt;The surface temperature is the temperature of the air at the surface (rather than the temperature of the ground itself).  This temperature is typically taken between 1 and 2 m off the ground, and this is the temperature we feel when we are outside.  Simply put, the reason air affects this temperature, sometimes radically, is because temperature is a property of the air (it is related to the mean kinetic energy of the molecules comprising the air). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we are curious about the change in temperature we experience, we might write $\frac{DT}{Dt}$, where $\frac{D}{Dt}$ is a material derivative and $T$ is temperature.  This change in temperature is Lagrangian, or in other words it is the temperature of a parcel of air as it moves around.  We can expand this as $$\frac{DT}{Dt} = \frac{\partial T}{\partial t} + \mathbf{u}\cdot\nabla T$$ What this equation says to us is this that the change in temperature can be related to two effects:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The change in temperature of air at a fixed location in space (e.g. outside your house), and&lt;/li&gt;&#xA;&lt;li&gt;The transport of different temperature air to your location by the wind.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The first bullet point is going to be modified by energy transfer between the ground and the air (conduction) and radiative losses (radiation emission).  These changes are on the scale of how temperature changes between morning and afternoon -- nothing too radical.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second bullet point is where the radical changes can take place.  Temperature is a property of the air, so if new air moves in to your location with a different temperature, that will strongly determine the local surface temperature. &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;You mention the polar vortex, which is a often misused term which has recently come into popular vocabulary.  The polar vortex is primarily a mid-upper atmospheric circulation above the poles.  When you hear it on TV you are most likely hearing it misused and the generally just mean a really strong cold front with a (perhaps unseasonably) cold arctic continental airmass behind it.  A front, in simple terms, is an enhanced surface temperature gradient that separates airmasses with different properties.  The key feature is a strong temperature gradient -- a relatively large change in surface temperature over a relatively small distance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This goes back to the earlier discussion on the primary contribution to radical changes in temperature being the wind bringing in air with a different temperature.  When a cold front arrives, it is being driven by the wind and this is an example of the transport of temperature by the wind (cold air advection).  &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;In summary, air affects local surface temperatues so strongly because temperature is a property of the air.  If the air currently around your town is replaced by new air, that air will have its own temperature and so you will experience a change in temperature -- if the new air is radically colder, you will experience a radical temperature change.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2014-12-07T04:02:36.687" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2975" PostTypeId="2" ParentId="167" CreationDate="2014-12-07T08:01:26.747" Score="5" Body="&lt;p&gt;One of the main difficulties in using older stromatolitic deposits, asides from the sparcity of deposits , is the debate of their biogenesis, particularly those from the Archaean (&lt;a href=&quot;http://arxiv.org/pdf/nlin/0401026.pdf&quot;&gt;1&lt;/a&gt;). However, 3.45 Ga coniform stromatolite deposits from the Pilbara region of Western Australia (with similar features as those already identified as biogenic), suggest that they were formed in a hypersaline depositional environment (&lt;a href=&quot;http://gsabulletin.gsapubs.org/content/111/8/1256&quot;&gt;2&lt;/a&gt;).  Warm, even arid environments are suggested by authors such as Chumakov (&lt;a href=&quot;http://elpub.wdcb.ru/journals/rjes/v05/tje03136/tje03136.htm&quot;&gt;3&lt;/a&gt;) and Medvedev et al. (&lt;a href=&quot;http://www.umanitoba.ca/science/geological_sciences/people/faculty/bekker/Medvedev-05.pdf&quot;&gt;4&lt;/a&gt;).  Below are a couple of examples alongside the paper that plannapus provided in the comment to the other answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the best preserved stromatolitic suites is, however, from the the Late Archaean (2.7 Ga) stromatolitic limestones within sulphide rich and tidal-flat sediments of the Manjeri and Cheshire Formations in the Belingwe Greenstone Belt of Zimbabwe (&lt;a href=&quot;http://sp.lyellcollection.org/content/199/1/309.abstract&quot;&gt;5&lt;/a&gt;), (&lt;a href=&quot;http://memoirs.gsapubs.org/content/198&quot;&gt;6&lt;/a&gt;). The authors observe that the stromatolites, in conjuction with the sulphides and tidal flat deposits indicate that there was a thriving prokaryotic community of oygenetic photosynthesisers and sulphate reducers, also with possible methanogenesis and methanotrophy - the implication according to the authors is that these suggest well developed carbon and sulfur cycles - that &lt;em&gt;could have been&lt;/em&gt; global.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Microstromatolitic deposits from the 2.2-2.1 Ga carbon excursion described by Medvedev et al. 2005 (&lt;a href=&quot;http://www.umanitoba.ca/science/geological_sciences/people/faculty/bekker/Medvedev-05.pdf&quot;&gt;4&lt;/a&gt;) have been found alongside other inclusions that indicate that the environment of their formation was warm and arid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Within the research, it becomes clear that stromatolitic deposits, alongside other sedimentary structures and included isotopes are a reasonable way to gauge the climatic and even, at least part, of the biogeochemical cycles of the time.  However, as in the Memoirs edited by Kesler and Ohmoto (&lt;a href=&quot;http://memoirs.gsapubs.org/content/198&quot;&gt;6&lt;/a&gt;), greater constraints of the conditions can be made using the mineralogical ore deposits within the ancient cratons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Note: Ga = billion years&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://arxiv.org/pdf/nlin/0401026.pdf&quot;&gt;1&lt;/a&gt;) Batchelor et al. 2004 &lt;a href=&quot;http://arxiv.org/pdf/nlin/0401026.pdf&quot;&gt;A case for biotic morphogenesis of coniform&#xA;stromatolites&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://gsabulletin.gsapubs.org/content/111/8/1256&quot;&gt;2&lt;/a&gt;) Hofmann et al. 1999 &lt;a href=&quot;http://gsabulletin.gsapubs.org/content/111/8/1256&quot;&gt;Origin of 3.45 Ga coniform stromatolites in Warrawoona Group, Western Australia&lt;/a&gt;, Geological Society of America Bulletin&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://elpub.wdcb.ru/journals/rjes/v05/tje03136/tje03136.htm&quot;&gt;3&lt;/a&gt;) Chumakov 2003 &lt;a href=&quot;http://elpub.wdcb.ru/journals/rjes/v05/tje03136/tje03136.htm&quot;&gt;Global climates of the Vendian&lt;/a&gt; Russian Journal of Earth Sciences&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.umanitoba.ca/science/geological_sciences/people/faculty/bekker/Medvedev-05.pdf&quot;&gt;4&lt;/a&gt;) Medvedev et al. 2005 &lt;a href=&quot;http://www.umanitoba.ca/science/geological_sciences/people/faculty/bekker/Medvedev-05.pdf&quot;&gt;Testing the Biostratigraphic Potential of Early Palaeoproterozoic Microdigitate Stromatolites&lt;/a&gt; Revista Española de Micropaleontología&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://sp.lyellcollection.org/content/199/1/309.abstract&quot;&gt;5&lt;/a&gt;) Grassineau et al. 2002 &lt;a href=&quot;http://sp.lyellcollection.org/content/199/1/309.abstract&quot;&gt;Stable isotopes in the Archaean Belingwe belt, Zimbabwe: evidence for a diverse microbial mat ecology&lt;/a&gt; The Geological Society of London &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://memoirs.gsapubs.org/content/198&quot;&gt;6&lt;/a&gt;) Kesler and Ohmoto, 2007 &lt;a href=&quot;http://memoirs.gsapubs.org/content/198&quot;&gt;Evolution of Early Earth's Atmosphere, Hydrosphere, and Biosphere - Constraints from Ore Deposits&lt;/a&gt; Memoir of the Geological Society of America&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-12-07T08:21:30.713" LastActivityDate="2014-12-07T08:21:30.713" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2976" PostTypeId="2" ParentId="2122" CreationDate="2014-12-07T08:09:32.333" Score="8" Body="&lt;p&gt;I'd like to add to David's excellent answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your premise is that there are &quot;mountains before erosion&quot; is not exactly accurate. Mountains, in the sense that think of them (local elevated regions above their surroundings, e.g. Mont Blanc) form &lt;em&gt;because&lt;/em&gt; of erosion. In that case, mountains without erosion would simply not be mountains. Note that there can be two kinds of erosion: physical weathering and chemical weathering. A bit more about it in &lt;a href=&quot;https://earthscience.stackexchange.com/a/2306/725&quot;&gt;https://earthscience.stackexchange.com/a/2306/725&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's take at look some examples:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/e1mGw.png&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Tibetan plateau is elevated because of the collision of two continental lithospheric plates. If you look at the topography, you will see that areas that are not nearby any serious elevation differences are not that jagged, for example in the center north area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Xns6W.jpg&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An example from the Grand Canyon. Looking down from the Colorado river, I'm pretty sure that you will agree the it's a mountain, and a jagged one. But other than that, there is nothing. It's a flat plateau. The Colorado plateau is very high in elevation, but without erosion it simply doesn't look like a mountain at all.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-12-07T08:09:32.333" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2980" PostTypeId="1" AcceptedAnswerId="2982" CreationDate="2014-12-07T13:48:31.480" Score="11" ViewCount="407" Body="&lt;p&gt;I am working on a data visualisation of airline flight paths and their probability of forming contrails.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given weather data for a specific area (location, time, temperature, pressure and humidity) and aircraft data (location, time, altitude, speed and engine efficiency)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there an equation that will give me a rough estimate of the probability contrails will form at this point?&lt;/p&gt;&#xA;" OwnerUserId="1274" LastActivityDate="2014-12-07T21:23:52.517" Title="Equation for predicting contrail formation" Tags="|climate-change|nwp|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2981" PostTypeId="2" ParentId="922" CreationDate="2014-12-07T19:19:06.360" Score="5" Body="&lt;p&gt;Earthquakes involve slip on faults, most of which occur on plate boundaries. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now the width of a fault is usually limited by the downdip limit of the brittle ductile transition. E.g., in case of vertical strike slip faults this limit is between 10-20 km. In subduction zones this limit can be larger as the fault/interface is inclined.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The theoretical length of the fault is limited by the length of the plate boundary. It is impossible to have a fault with a length greater than the circumference of earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The final variable is slip. Average slip, based on empirical relationships, doesn't exceed more than 5-15m (rocks can accumulate only so much strain). Though locally it is possible to have slip as high as 50m (e.g., in the case of the Tohoku earthquake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So for a plate boundary fault which exactly splits the earths brittle upper crust into two halves (in a single earthquake) with an average slip of 15 m, assuming a modulus of rigidity of 30GPa (mean for upper crust) we have:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Moment = Fault_area x rigidity x slip&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;which for our hypothetical scenario is equal to&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;= ((2*pi*6371000)*20000)*(30e9)*(15)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;or&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;3.6E23 Nm&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;which is about Mw9.7.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastActivityDate="2014-12-07T19:19:06.360" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2982" PostTypeId="2" ParentId="2980" CreationDate="2014-12-07T20:53:54.110" Score="7" Body="&lt;p&gt;Schmidt-Appleman criterion (SAC) is used to model contrail formation. I advise reading in full Ulrich Schumann's article &quot;A contrail cirrus prediction model&quot; (&lt;a href=&quot;http://www.geosci-model-dev.net/5/543/2012/gmd-5-543-2012.pdf&quot;&gt;http://www.geosci-model-dev.net/5/543/2012/gmd-5-543-2012.pdf&lt;/a&gt;) to get all the relevant formulae and literature references.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;While it is possible to transcribe the formulae here, the reference cited does a better job of presenting state of the art (2012).&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="269" LastEditorUserId="269" LastEditDate="2014-12-07T21:23:52.517" LastActivityDate="2014-12-07T21:23:52.517" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2983" PostTypeId="2" ParentId="878" CreationDate="2014-12-07T21:28:18.997" Score="9" Body="&lt;p&gt;See it is relatively easy to predict where a large earthquake might occur, assuming you have been monitoring deformation for a long enough period, more or less equal to the average inter-seismic interval (decades-centuries). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In principle earthquakes are simple, i.e., the fault accumulates strain and then eventually slips/ruptures. The million dollar question is what triggers it, and till date there has not been a single reliable precursor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is like predicting failure of a wooden (e.g., balsa) stick by bending the two sides with your hands, i.e., you know it will break more or less somewhere near the center, where the strain is highest (assuming homogeneity in properties and geometry) but getting the timing right is significantly harder and very difficult to reproduce. It is even harder in case of earthquakes, given the heterogeneity, non-linearity in the system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So with time it will get easier to predict location of large earthquakes, as we monitor strain accumulation using modern tools like GPS, InSAR etc., but getting the timing right to even within a few years will be much harder. For example, we know that Southern San Andreas is due to for an earthquake (just based on the amount of slip deficit) as the last major earthquake was in 1857. But will this earthquake occur, today, in five years or within next 50 years, is unknown. Having said that additional faults in SoCal (e.g., San Jacinto and Elsinore) make the situation even more complex. Same goes for the North Anatolian fault near Istanbul, i.e., we know that an earthquake will occur there soon, as the entire plate boundary except the part near Istanbul had ruptured at least once in the last hundred years. See &lt;a href=&quot;http://www.ipgp.fr/~armijo/paraseminario/Stein-97.pdf&quot;&gt;here&lt;/a&gt; for more details.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But getting the timing right for short term forecasts right now (and IMHO even in the next few decades) is impossible. Your only hope is alarms based on P-wave arrivals but then the earthquake has already started and heading towards you. Note: P waves arrive faster than surface waves, which cause most of the destruction so you might have a few seconds (depending on how far you are from the hypocenter) to take cover, automatically shutdown crucial stuff like gas flow in underground pipelines, subways, power plants etc.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2014-12-07T21:57:42.557" LastActivityDate="2014-12-07T21:57:42.557" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2984" PostTypeId="1" AcceptedAnswerId="2995" CreationDate="2014-12-07T22:20:14.690" Score="14" ViewCount="209" Body="&lt;p&gt;In reading about historical major earthquakes, in particular, the &lt;a href=&quot;http://www.history.com/this-day-in-history/deadliest-earthquake-in-history-rocks-china&quot;&gt;Great Shaanxi Earthquake&lt;/a&gt; that killed approximately 830,000 people in July, 1556, there is a claim made about the approximate Richter scale magnitude:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Later scientific investigation revealed that the magnitude of the quake was approximately 8.0 to 8.3&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;despite this earthquake obviously pre-dating the development of the Richter Scale.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What do geologists look for to estimate the magnitude of past major earthquakes?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-12-08T02:57:29.977" LastActivityDate="2014-12-09T13:29:06.730" Title="How are Richter magnitudes of past earthquakes estimated?" Tags="|geophysics|seismology|earthquakes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2986" PostTypeId="1" CreationDate="2014-12-08T01:04:06.793" Score="4" ViewCount="45" Body="&lt;p&gt;I am trying to classify a bravais lattice. It is a hexagonaly close packed lattice with (ABC) planes, that is fcc, but it is squeezed along the stacking direction, so perpendicular to the planes. Just like ABC hexagonal close packing of smarties.&lt;/p&gt;&#xA;" OwnerUserId="1283" LastActivityDate="2014-12-08T01:04:06.793" Title="What is the name for a ABC hcp lattice that is squeezed along the direction vertical to the ABC planes?" Tags="|crystals|crystallography|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2987" PostTypeId="2" ParentId="2970" CreationDate="2014-12-08T01:14:25.050" Score="13" Body="&lt;p&gt;Considering that the Mid-Atlantic ridge was just discovered recently (in geological terms), much of the Earth's water is still unmapped. The surface can be easily mapped by satellites, as said by farrenthorpe. It's just undersea territory which remains a deep mystery (no pun intended).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some question the fact that we can estimate the depth of the Mariana Trench, but not map the seafloor. In that case, think about using a ruler. You can measure the length, width, or height of any object. But can you determine what the object looked like?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With advancing technology, more of the seafloor is explored everyday and sometimes we find new patterns, like the Mid-Atlantic ridge. Good luck geology!&lt;/p&gt;&#xA;" OwnerUserId="1282" LastActivityDate="2014-12-08T01:14:25.050" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2988" PostTypeId="2" ParentId="1037" CreationDate="2014-12-08T01:30:29.937" Score="0" Body="&lt;p&gt;Considering what I've learned about CFC - chlorofluorocarbons, O&lt;sub&gt;3&lt;/sub&gt; is easily &quot;annihilated&quot; into O&lt;sub&gt;2&lt;/sub&gt; and chlorine-containing compounds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See, CFCs are a group of chemicals found in pressurized containers which, as said in its name, contain chlorine, fluorine, or another halogen. When they reach the ozone layer (from anywhere between 1 week and a few years), they form bonds with the ozone and hijack an O atom to form ClO (chlorine monoxide). The by-product O&lt;sub&gt;2&lt;/sub&gt; sinks downwards for some reason. The ClO meets a free oxygen atom and breaks into more O&lt;sub&gt;2&lt;/sub&gt;, and Cl&lt;sup&gt;-&lt;/sup&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would say that ozone would remain in the atmosphere until CFCs come murder it, probably at least 5 weeks.&lt;/p&gt;&#xA;" OwnerUserId="1282" LastEditorUserId="1282" LastEditDate="2014-12-08T02:48:45.303" LastActivityDate="2014-12-08T02:48:45.303" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="2989" PostTypeId="2" ParentId="1019" CreationDate="2014-12-08T09:39:24.710" Score="6" Body="&lt;p&gt;This is somewhat a partial answer, as there is still a considerable amount of research being performed on the effects of the Garbage Patch.  The focus of this nswer will concentrate on what the US EPA (&lt;a href=&quot;http://www.epa.gov/region9/marine-debris/pdf/MarineDebris-NPacFinalAprvd.pdf&quot; rel=&quot;nofollow&quot;&gt;3&lt;/a&gt;) identifies as being the pollutant that contributes 96% of the Garbage Patches in the north Pacific - 'microplastics', pellets less than 5 mm in size.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to Rios et al. 2010 (&lt;a href=&quot;http://www.caseinlet.org/uploads/Moore-Rios_et_al__2010_1_.pdf&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt;), the plastic in the North Pacific Gyre are found to function as &quot;a solid-phase extraction media&quot; causing adsorption and concentration of pollutants out of the water column, similar to what has been found for marine sediments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, microplastics are found to be what Rios et al. (&lt;a href=&quot;http://www.caseinlet.org/uploads/Moore-Rios_et_al__2010_1_.pdf&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt;) describe as being &quot;inverse sediments&quot; in that they do the opposite of natural marine sediments and remain floating on or near the ocean surface. Zarfi et al. 2011 (&lt;a href=&quot;http://epic.awi.de/24543/1/Marine_Pollution_Bulletin_62_(2011)_1589%E2%80%931591.pdf&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;) observed that microplastics can be incorporated into the natural sediments, and potentially wash up on beaches (e.g. if caught in a coastal current as seen n the diagram below) etc - whether or not, being incorporated into these natural sedimentation processes provides a 'sink' for the microplastics is still unclear (&lt;a href=&quot;http://epic.awi.de/24543/1/Marine_Pollution_Bulletin_62_(2011)_1589%E2%80%931591.pdf&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.caseinlet.org/uploads/Moore-Rios_et_al__2010_1_.pdf&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt;) Rios et al. 2010, &lt;a href=&quot;http://www.caseinlet.org/uploads/Moore-Rios_et_al__2010_1_.pdf&quot; rel=&quot;nofollow&quot;&gt;Quantitation of persistent organic pollutants adsorbed on plastic debris&#xA;from the Northern Pacific Gyre’s ‘‘eastern garbage patch’’&lt;/a&gt;, &lt;em&gt;Journal of&#xA;Environmental&#xA;Monitoring&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://epic.awi.de/24543/1/Marine_Pollution_Bulletin_62_(2011)_1589%E2%80%931591.pdf&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;) Zarfi et al. 2011, &lt;a href=&quot;http://epic.awi.de/24543/1/Marine_Pollution_Bulletin_62_(2011)_1589%E2%80%931591.pdf&quot; rel=&quot;nofollow&quot;&gt;Microplastics in oceans&lt;/a&gt;, &lt;em&gt;Marine Pollution Bulletin&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.epa.gov/region9/marine-debris/pdf/MarineDebris-NPacFinalAprvd.pdf&quot; rel=&quot;nofollow&quot;&gt;3&lt;/a&gt;) US EPA, 2011, &lt;a href=&quot;http://www.epa.gov/region9/marine-debris/pdf/MarineDebris-NPacFinalAprvd.pdf&quot; rel=&quot;nofollow&quot;&gt;Marine Debris in the North Pacific&lt;/a&gt;, &lt;em&gt;U.S. Environmental Protection Agency&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-01-03T18:02:13.187" LastActivityDate="2015-01-03T18:02:13.187" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2990" PostTypeId="2" ParentId="2583" CreationDate="2014-12-08T17:59:30.817" Score="9" Body="&lt;p&gt;Earthquakes, specially those at subduction zones, result in redistribution of mass (as one plate slides on top of the other). This change in distribution of mass causes changes in gravitational field that can be measured by satellites such as GRACE.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now angular momentum is conserved. If we know the change in mass then we can calculate the change in moment of inertia and thus the change in the angular velocity.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastActivityDate="2014-12-08T17:59:30.817" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2991" PostTypeId="2" ParentId="49" CreationDate="2014-12-08T19:39:12.680" Score="7" Body="&lt;p&gt;The only similarity that they are fluids and therefore NS applies. Actually, to be fair mantle is solid as it allows shear waves to propagate through. However, on geologic time scales it behaves like a viscous fluid and can be modeled as such.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Circulation models solve compressible (non-hydrostatic) Euler equations where as mantle convection is governed by incompressible Stokes flow. The types of core numerical solvers and  numerical schemes used by the two communities are very different (e.g., explicit for circulation models and implicit for convection models). The only common aspect is that both use a spherical geometry/meshes to solve the equations. Circulation models also have to account for topography but most mantle convection models neglect it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Having said that both require some basic background in CFD so in that sense they are similar. Some of the earliest mantle convection models were written by aerospace engineers.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2014-12-08T19:46:09.820" LastActivityDate="2014-12-08T19:46:09.820" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2992" PostTypeId="1" CreationDate="2014-12-09T02:58:32.153" Score="9" ViewCount="14378" Body="&lt;p&gt;Why is the geostatic (or is it the lithostatic?) gradient 1 psi/ft?  How is that derived from g/cc? Thanks.&lt;/p&gt;&#xA;" OwnerUserId="538" LastEditorUserId="28050" LastEditDate="2014-12-09T13:28:21.763" LastActivityDate="2019-09-20T03:12:50.377" Title="Why is the lithostatic pressure gradient 1 psi/ft? How is it derived from density?" Tags="|geophysics|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="2993" PostTypeId="2" ParentId="2970" CreationDate="2014-12-09T10:10:41.577" Score="12" Body="&lt;p&gt;A lot depends on the definition of &quot;charted&quot;. How much detail must we know for an area to gain this status? As others have said, we have a low-resolution idea of all of the non-ice-covered seabed from satellite altimetry and gravity measurements - but there is a big difference between this, with a resolution measured in miles, and a high-resolution multibeam sonar survey in coastal waters that might resolve down to less than a metre.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Most of the planet is known to a very coarse level.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Much, but not all, of the planet's coastal waters have been surveyed at one time or another, often by colonial navies. A lot of modern Admiralty charts have sections for which the last survey was conducted in (say) 1882. These surveys were conducted by a man dropping a lead weight over the side of a ship and measuring how far it fell; neither their accuracy nor their resolution is up to modern standards and, even if the measurements were accurate when taken, sediments may have moved in the time since.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Very small areas of the seafloor (relative to the total area) have been mapped recently to modern standards. These are areas that are of interest for one reason or another: for navigation into major ports, for scientific interest where there are strong currents, for engineering purposes prior to offshore construction projects, and so forth.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="39" LastActivityDate="2014-12-09T10:10:41.577" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2994" PostTypeId="1" AcceptedAnswerId="3000" CreationDate="2014-12-09T11:09:33.943" Score="8" ViewCount="1197" Body="&lt;p&gt;Reading the Physics.SE question &lt;a href=&quot;https://physics.stackexchange.com/questions/94200/what-is-the-current-physical-theory-of-what-causes-the-morning-glory-roll-clou&quot;&gt;What is the current physical theory of what causes the 'Morning Glory' roll cloud over Northern Australia?&lt;/a&gt; (pictured below):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/7drV2.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image source: &lt;a href=&quot;http://apod.nasa.gov/apod/ap090824.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA Astronomy picture of the day 24 August, 2009&lt;/a&gt; of a Morning Glory roll-cloud over northern Australia. The origin and processes are quite well understood.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the paper linked in the answer: &lt;a href=&quot;http://homepages.see.leeds.ac.uk/~eeaol/p/smith1988.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Travelling Waves and Bores in the Lower Atmosphere:&#xA;The 'Morning Glory' and Related Phenomena&lt;/a&gt; (Smith, 1988), the author expressed an uncertainty in his concluding remarks, which are the basis of this question:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The structure and origin of northeasterly&#xA;  morning glories is relatively well-understood,&#xA;  although &lt;em&gt;questions remain about the precise&#xA;  mechanisms inhibiting the leakage of wave&#xA;  energy to the upper atmosphere, and the&#xA;  transformation of disturbances over the land&#xA;  during the day when the original wave-guide&#xA;  is destroyed by convective mixing.&lt;/em&gt; &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The italicised portion suggests that some mechanism(s) prevents these effects from occurring, resulting in the roll-cloud persisting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What meteorological factors maintain the Morning Glory roll-clouds?&lt;/strong&gt; &lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2017-04-13T12:40:15.470" LastActivityDate="2015-10-24T09:23:34.927" Title="How are 'Morning Glory' clouds maintained?" Tags="|meteorology|clouds|solitary-waves|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2995" PostTypeId="2" ParentId="2984" CreationDate="2014-12-09T13:29:06.730" Score="5" Body="&lt;p&gt;The approximate magnitude of ancient historic earthquakes may be estimated using a &lt;a href=&quot;http://earthquake.usgs.gov/learn/topics/mag_vs_int.php&quot;&gt;Magnitude/Intensity comparison&lt;/a&gt; based on modern earthquakes.  Earthquake intensity may be estimated from the descriptions written down by people. The Chinese officials made detailed records of the damage caused by large earthquakes. &lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-12-09T13:29:06.730" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="2996" PostTypeId="2" ParentId="2992" CreationDate="2014-12-09T14:31:52.923" Score="9" Body="&lt;p&gt;Lithostatic pressure might be roughly 23 kPa/m (about 1 psi/ft) in young basins dominated by siliciclastic rocks, but it varies substantially. Pressure has a linear relationship to density. Let's explore the relationship, and the variance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First some definitions:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Lithostatic pressure&lt;/strong&gt; — vertical pressure due to the weight of rock and fluid. &lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Hydrostatic pressure&lt;/strong&gt; — vertical pressure due to the weight of fluid only.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Fracture pressure&lt;/strong&gt; — the pressure at which the rock fractures.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Pore pressure&lt;/strong&gt; — the pressure in the pores of a rock; usually close to hydrostatic.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;There's a lot of jargon in this field — lithostatic pressure is sometimes called confining pressure, overburden pressure, vertical stress, total stress, and various other things. I hadn't heard of &lt;strong&gt;geostatic pressure&lt;/strong&gt; before, and a quick bit of research revealed that some people call the pressure due to rock and fluid 'lithostatic' and some call it 'geostatic', reserving 'lithostatic' for the pressure due to the dry rock only. In my experience, it doesn't pay to be pedantic about these inconsistencies, all you can do is spell out what you mean. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We'll do a quick derivation &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2106/how-do-i-derive-the-formula-for-lithostatic-overburden-pressure&quot;&gt;(there's a more comprehensive one here)&lt;/a&gt;. Pressure $P$ is force $F$ per unit area, and Newton told us that $F = ma$, where $m$ is mass and $a$ is acceleration. Since we're interested in vertical pressure, acceleration is &lt;a href=&quot;https://en.wikipedia.org/wiki/Acceleration_due_to_gravity&quot; rel=&quot;nofollow noreferrer&quot;&gt;due to gravity&lt;/a&gt; so we can use $g$. We know the mass of a rock normalized to volume as density $\rho$, and we're interested in a depth $d$, so:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$P = \rho d g$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The units are $[\mathrm{kg/m}^3] \times [\mathrm{m}] \times [\mathrm{m/s}^2]$ or newtons per square metre, N/m$^2$, which we call pascals, Pa, for convenience (10 kPa &lt;a href=&quot;https://www.google.ca/search?q=1000%20pa%20in%20psi&quot; rel=&quot;nofollow noreferrer&quot;&gt;is 1.45 psi&lt;/a&gt;). Note that in the real world density varies with depth, so &lt;a href=&quot;https://en.wikipedia.org/wiki/Overburden_pressure&quot; rel=&quot;nofollow noreferrer&quot;&gt;you'll need to integrate&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because the pressure increases roughly linearly with depth, it's often convenient to talk about the &lt;em&gt;pressure gradient&lt;/em&gt;, which is usually expressed in units of kPa/m, and of course is just the gradient of a line on a pressure–depth plot, like in the example below from a fictional offshore well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So where does 23 kPa/m come from? If we take an approximate average density of sedimentary rock as 2300 kg/m$^3$, then $P = 2300 \times g$ Pa/m, or about 23 kPa (we often round $g$ to 10). Different mineralogies, different porosities, different fluids — all these will change the lithostatic pressure gradient.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Hl3mT.png&quot; alt=&quot;Pressure in an offshore well&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-12-09T18:07:56.073" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2997" PostTypeId="1" CreationDate="2014-12-09T17:07:57.697" Score="11" ViewCount="1990" Body="&lt;p&gt;Inertial and symmetric instabilities are fluid instabilities present in atmosphere and ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the difference between an inertial instability and a symmetric instability?&lt;/p&gt;&#xA;" OwnerUserId="86" LastActivityDate="2014-12-11T18:05:45.670" Title="What is the difference between an inertial instability and a symmetric instability?" Tags="|meteorology|oceanography|fluid-dynamics|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="2998" PostTypeId="2" ParentId="2992" CreationDate="2014-12-09T17:10:35.207" Score="5" Body="&lt;p&gt;Overburden/Lithostatic/Geostatic pressure (or stress) at a given depth is the vertical pressure (or stress) due to the weight of a column of rock and the fluids contained in the rock above that depth.  The pressure applied by a resting rock mass (this includes the fluids within the rock's pore space) under the acceleration of gravity is related to the rock's mass density by the formula, &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\tag{1} p(z) = p_o+\int_0^z\rho(z) g \ dz$$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $p(z)$ is pressure at depth $z$, $p_o$ is the datum pressure, $\rho (z)$ is the &lt;a href=&quot;http://en.wikipedia.org/wiki/Bulk_density&quot; rel=&quot;nofollow noreferrer&quot;&gt;bulk density&lt;/a&gt; for the rock mass (rock matrix plus the mass in its pore space) as a function of depth, and $g$ is the acceleration due to gravity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/2106/how-do-i-derive-the-formula-for-lithostatic-overburden-pressure&quot;&gt;See here&lt;/a&gt; for a more comprehensive derivation for the pressure-density-depth relationship shown in Equation 1.  This explanation assumes the International System of units, and provides a gradient in units Pa/m.  See &lt;a href=&quot;https://physics.stackexchange.com/questions/145010/calculating-pressure-under-water/145046#145046&quot;&gt;my explanation here&lt;/a&gt; for how to convert SI units to the American Engineering System of units, which uses psi/ft.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://physics.stackexchange.com/questions/107824/what-is-the-difference-between-stress-and-pressure&quot;&gt;See here&lt;/a&gt; for a discussion on why overburden pressure is assumed to be equal to overburden stress.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the assumption of 1 psi/ft, the bulk density of the rock will be assumed a constant.  Gauge pressure will be assumed, therefore $p_o$ will be 0 psig since the datum will be selected to be at the surface of the earth.  A constant bulk density can be assumed if the grain density of the rock matrix, liquid water density in the pore space of the rock, and porosity value of the rock are assumed.  The bulk density can be estimated as, &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\rho_t = [\rho_m \times (1-\phi)]+[\rho_w \times \phi]$$  where $\rho_m$ is the weighted average of grain (mineral) density (sandstone and shale = 2.65 g/cc), $\rho_w$ is the weighted average of pore-water density (g/cc), and $\phi$ is the weighted average of the rock porosity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get a value of 1 psi/ft, we will assume $\rho_m = 2.65$ g/cc, $\rho_w = 1.05$ g/cc, and $\phi \approx 21.457$%.  This will give a bulk density of $\rho_t \approx 2.306682$ g/cc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is 0.0022046 lb-mass per gram and 28316.85 cubic centimeters per cubic foot.  Therfore $\rho_t \approx 2.306682$ g/cc $= 144$ lbm/ft^3.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Substituting this density value into the equation presented in the &lt;a href=&quot;https://physics.stackexchange.com/questions/145010/calculating-pressure-under-water/145046#145046&quot;&gt;link&lt;/a&gt; for using American Engineering System of units, assuming $D=1$ft:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\frac{p}{D}=\nabla p=\frac{(\rho g_c)}{144g}$$ where $g_c$ is the gravitational constant of acceleration (32.2 ft/sec^2) and $g$ is the units conversion factor to lbf (32.2 $\frac{lbm \ ft/sec^2}{lbf}$), you should get 1 psi/ft.&lt;/p&gt;&#xA;" OwnerUserId="538" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-12-09T18:09:18.847" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="2999" PostTypeId="1" AcceptedAnswerId="3002" CreationDate="2014-12-09T18:57:45.100" Score="13" ViewCount="625" Body="&lt;p&gt;I noticed that in some science fiction movies set in the future on Earth, like Wall-E and Interstellar, dust storms are very prominent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any scientific hypotheses suggesting that dust storms may become more frequent in the future?&lt;/p&gt;&#xA;" OwnerUserId="1288" LastEditorUserId="192" LastEditDate="2014-12-09T20:56:39.123" LastActivityDate="2014-12-12T03:03:58.993" Title="Will dust storms be more frequent in the future?" Tags="|meteorology|planetary-science|atmospheric-dust|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="3000" PostTypeId="2" ParentId="2994" CreationDate="2014-12-09T20:40:09.953" Score="7" Body="&lt;p&gt;These are some of the most recent areal photographs taken of this phenomenon. The Morning Glory clouds are the visible manifestation of atmospheric Internal Solitary Waves (see the schematic in (b) below). They propagate on a sharp interface between a relatively dry layer ambient air above and a layer of sea water laden air pushed in from the night before below. When the moist air rises the cloud is formed above the condensation level and eventually evaporates at the trailing edge of the wave.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In these photographs, the cloud itself appears as a cylindrical shaped core with high vorticity at a height of $500$ m and a $1$ km diameter. They may stretch for thousands of kms while traveling at up to $50$ km/h.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Internal Solitary Waves are stable by definition, they are waves of permanent form which owe their existence due to a balance between nonlinear wave-steepening and linear wave dispersion. Of course in the environment there are several other nonlinearities which could potentially break apart this structure through various mechanisms. However, devoid of other atmospheric forcing these waves can travel thousands of KMs without loosing much energy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A final point is that these waves are ubiquitous but the thing is that we very rarely can observe them is such glorious ways, so there is nothing that says that the Morning Glory is special as far as stability goes compared to other locations on Earth. It is in fact common for such disturbances to maintain their shape over large distances.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/87aRQ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/VgqT4.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/ATQmI.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://scitation.aip.org/content/aip/journal/pof2/26/9/10.1063/1.4894075&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ouazzani, Zaim R., et al. &quot;The Morning Glory: Flow visualization by Mother Nature.&quot; Physics of Fluids (1994-present) 26.9 (2014): 091110.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="200" LastActivityDate="2014-12-09T20:40:09.953" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3001" PostTypeId="1" AcceptedAnswerId="3003" CreationDate="2014-12-10T01:19:05.107" Score="9" ViewCount="2987" Body="&lt;p&gt;Popular film culture often depicts much volcanic activity during the time of the dinosaurs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming &quot;time of the dinosaurs&quot; as the Jurassic (200 million years ago) until the end of the Cretaceous (66 million years ago):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Are there any geological theories that support such an assumption?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="1290" LastEditorDisplayName="user889" LastEditDate="2015-03-26T08:49:26.670" LastActivityDate="2015-03-26T08:49:26.670" Title="Was volcanic activity more prevalent when the dinosaurs roamed?" Tags="|volcanology|earth-history|volcanoes|cretaceous|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="3002" PostTypeId="2" ParentId="2999" CreationDate="2014-12-10T03:56:25.480" Score="11" Body="&lt;p&gt;Most dust storms occur down-wind from areas with a lack of moisture, little vegetation, and high soil content.  Vegetative roots help to keep the soil intact when there is a lack of moisture. So any shift in the future that leads to a net decrease in vegetation, net decrease in precipitation, or an increase in exposed soil content will increase dust storm occurrence.  Thus, the most plausible reasons for increased dust storms in the future that have related scientific research are: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;land-surface changes due to human influence: forests/vegetation being replaced by land management practices for agriculture or mining that do not sustain roots in the soil or expose more soil&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;decreases in precipitation (e.g. due to climate change) that potentially lead to desertification of the region.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;diversion of rivers for human use, thereby removing water from any ecosystems that were previously downstream&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;extreme cataclysmic events (e.g. comet impact or nuclear war) that causes removal of most vegetation&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;So, in my opinion, it is a very real possibility that if humans continue to cause a net decrease in vegetation... there will be increases in dust storms.  However, there are good land management practices that can curtail dust entrainment into the atmosphere, such as those adopted after the historic 1930s &quot;Dust Bowl&quot; in America.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, from IRO-bot's comment link to &lt;a href=&quot;http://en.wikipedia.org/wiki/Dust_storm&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia dust storms&lt;/a&gt;: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It has been argued that recently, poor management of the Earth's drylands, such as neglecting the fallow system, are increasing dust storms size and frequency from desert margins and changing both the local and global climate, and also impacting local economies.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="20" LastEditDate="2014-12-12T03:03:58.993" LastActivityDate="2014-12-12T03:03:58.993" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="3003" PostTypeId="2" ParentId="3001" CreationDate="2014-12-10T07:57:29.937" Score="5" Body="&lt;p&gt;There seems to be indeed reasons to believe in an enhanced volcanism during the Cretaceous at least.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Cretaceous timescale is indeed peppered by the formation of large igneous provinces (known collectively as LIP; short review in &lt;strong&gt;Ogg &amp;amp; Hinnov 2012a&lt;/strong&gt;): Parana at ca. 135Ma, the Ontong-Java Plateau at ca. 125Ma, the Kerguelen Plateau at 118Ma, the Caribbean Province at 90Ma and of course the famous Deccan Traps at the K/Pg boundary. In addition to those large events, they were as well other more minor pulses of large-scale volcanism during the earliest Cretaceous (Shatsky Rise), and at ca. 87Ma (Madagascar Traps) and ca. 73Ma (Sierra Leone Rise).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The 5 LIP, though localized to a specific region each time, had a global impact on the climate and on the oceans, as seen on $\delta ^{13}C$ curves for instance, or during the different episodes of Oceanic Anoxic Events.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as the pop culture trope is concerned, most of these volcanic events were partly underwater (Shatsky Rise, Sierra Leone Rise, Kerguelen Plateau, Ontong-Java) so I doubt dinosaurs were roaming around active volcanoes. It is probable that the trope originated instead in the idea that the Deccan Traps triggered the end Cretaceous mass extinction (i. e. the disparition of non-avian dinosaurs, in particular).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In comparison (see &lt;strong&gt;Ogg &amp;amp; Hinnov 2012b&lt;/strong&gt;), there were only one LIP forming during the Jurassic in the Karoo Basin (South Africa); if we ignore the Central Atlantic Magmatic Province which formed just below the base of the Jurassic (it may or may not have caused the end-triassic mass extinction).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Ogg, J. G. &amp;amp; L. A. Hinnov, 2012a. Cretaceous. In F. Gradstein et al (Eds), The Geologic Time Scale 2012, Elsevier, Amsterdam: 793-853.&lt;br&gt;&#xA;Ogg, J. G. &amp;amp; L. A. Hinnov, 2012b. Jurassic. In F. Gradstein et al (Eds), The Geologic Time Scale 2012, Elsevier, Amsterdam: 731-791.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-12-10T09:20:23.890" LastActivityDate="2014-12-10T09:20:23.890" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3004" PostTypeId="1" CreationDate="2014-12-10T08:59:54.360" Score="11" ViewCount="1338" Body="&lt;p&gt;The shield volcano &lt;a href=&quot;http://mars.jpl.nasa.gov/gallery/atlas/olympus-mons.html&quot; rel=&quot;noreferrer&quot;&gt;Olympus Mons&lt;/a&gt; on Mars has the distinction of being the most massive single volcano in the solar system - this volcano, according to NASA, is 25km high with a diameter of over 600km - with a base that would cover the American state of Arizona (as in the image below).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/WXspB.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image source: &lt;a href=&quot;http://mars.jpl.nasa.gov/gallery/atlas/olympus-mons.html&quot; rel=&quot;noreferrer&quot;&gt;NASA&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What evidence, if any, has been found to prove that there ever has been a volcano the size of Olympus Mons on Earth?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-12-10T09:13:51.943" LastActivityDate="2014-12-11T23:17:38.600" Title="Olympus Mons sized volcano on Earth?" Tags="|volcanology|volcanoes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3005" PostTypeId="2" ParentId="3004" CreationDate="2014-12-10T08:59:54.360" Score="15" Body="&lt;p&gt;Recent studies have recognised what could be the most massive volcano in the world, a geological feature already known, but was not recognised until recently as being a single volcano.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is the &lt;a href=&quot;http://en.wikipedia.org/wiki/Tamu_Massif&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tamu Massif&lt;/a&gt; in the north-west Pacific (location map shown below), what was thought to be one of the vents of the Shatsky Rise - but recent seismic studies, reported in the article &lt;a href=&quot;http://www.nature.com/ngeo/journal/v6/n11/full/ngeo1934.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;An immense shield volcano within the Shatsky Rise oceanic plateau, northwest Pacific Ocean&lt;/a&gt; (Sager et al. 2013) have revealed that it is one single shield volcano. The Geology.com article states that it covers an area of approximately 310,800 square kilometers (120,000 square miles), about &quot;the size of New Mexico&quot; - and, according to Sager et al., &lt;strong&gt;making it comparable with the size of Olympus Mons&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Location of the Tamu Massif&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/oNl9i.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Map source: &lt;a href=&quot;http://www.dailymail.co.uk/sciencetech/article-2413612/Tamu-Massif-volcano-size-UK-discovered-beneath-Pacific-Ocean.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Daily Mail&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the article &lt;a href=&quot;http://www.nature.com/news/underwater-volcano-is-earth-s-biggest-1.13680&quot; rel=&quot;nofollow noreferrer&quot;&gt;Underwater volcano is Earth's biggest&lt;/a&gt; (Witze, 2013), that although the 140 million year old Tamu Massif is not as tall as Olympus Mons (nor even Mauna Kea) - in fact, it is still an impressive 4km above the sea floor, its 'footprint rivals that of Olmpus Mons', a comparison is shown below (the source is the linked article):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/nHThx.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The authors hint that seismic studies could well find more shield volcanoes on a par or even more massive than Olympus Mons. Of course, as they state, the identification of Tamu Massif as a Olympus Mons sized megavolcano suggests that there have been more such megavolcanoes in Earth's early history, most of course would be eroded, lost to tectonic processes etc. &lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-12-11T23:17:38.600" LastActivityDate="2014-12-11T23:17:38.600" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3006" PostTypeId="1" CreationDate="2014-12-10T09:28:22.747" Score="11" ViewCount="220" Body="&lt;p&gt;Global oil reserves are, for practical purposes, limited. We're using them at a rate far exceeding the rate of deposition. At some point, we will have to spend more energy to extract remaining reserves than we get back from burning them (extraction might still be worth it, because plastics and other oil products are really useful). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When is the point at which conventional oil production peaked/will peak?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the purposes of this question, please only consider conventional oil resources: that is, excluding shale oil, synthetic hydrocarbons, biofuels, oil sands, coal to liquids, and gas to liquids.&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="56" LastEditDate="2015-01-02T03:08:50.813" LastActivityDate="2015-01-02T03:08:50.813" Title="When did/will peak conventional oil happen?" Tags="|petrology|economic-geology|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="3008" PostTypeId="1" AcceptedAnswerId="3022" CreationDate="2014-12-10T21:54:58.800" Score="5" ViewCount="471" Body="&lt;p&gt;The Dune of Pilat (Dune du Pilat) is the tallest dune in Europe. The dune has been around for at least centuries. Where is the sediment coming from? Why is the dune so tall?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2014-12-11T16:53:53.510" LastActivityDate="2014-12-11T17:07:54.030" Title="What are the mechanisms maintaining the Dune of Pilat?" Tags="|sedimentology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3009" PostTypeId="1" CreationDate="2014-12-10T22:15:22.463" Score="-20" ViewCount="1334" Body="&lt;p&gt;Chemtrails are amazingly obvious in our daily life but why aren't we more concerned?  The information and patents for the chemicals we? are spraying are readily available.  The chemicals are huge pollutants and are changing the pH of soil and water. Do we really know enough to try to change the weather which is the 'why' they tell us and/or reduce global warming?  They've been doing this (supposedly for 60+ years.  Why aren't we more informed and concerned?&lt;/p&gt;&#xA;" OwnerUserId="606" LastActivityDate="2016-01-07T10:46:56.427" Title="Why aren't there more questions and concerns about chemtrails?" Tags="|meteorology|" AnswerCount="2" CommentCount="14" ClosedDate="2014-12-11T20:53:31.753" ContentLicense="CC BY-SA 3.0" />
  <row Id="3010" PostTypeId="2" ParentId="3009" CreationDate="2014-12-10T22:34:46.610" Score="27" Body="&lt;p&gt;Because chemtrails do not exist.  I am not only a meteorologist, but a former airline pilot.  In short (you can ask a new question about this if you are so interested), contrails are a form of a mixing cloud, the exact same mechanism that causes you to see your breath on a cold day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The saturation vapor pressure curve is exponential so it is possible to have two air parcels that are subsaturated, but when mixed produce a supersaturated parcel.  When jet engine exhaust and the ambient atmosphere are favorable, a contrail mixing cloud is what happens when they mix together.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The active chemical in a contrail is water vapor ($\ce{H2O}$) and carbon soot particles that perform as cloud condensation nuclei to allow condensed droplet formation (these are a byproduct of combustion).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Say it again with me:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Chemtrails do not exist&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To address your other points, there are processes that affect the pH of water and produce &quot;Acid rain&quot;.   The chemicals that form this, however, typically emanate from the smokestacks of coal burning power plants or other industrial pollutants that produce fine particles of acid salts that act as cloud condensation nuclei.  Airplanes are not part of this problem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as changing the weather goes, you are probably referring to cloud seeding via the release of silver iodide.  These are cloud condensation nuclei that promote droplet growth at low humidities and can be released to form precipitating clouds.  Specialized airplanes do this in very specific places and at low levels.  These are not in any way related to the contrails you see from normal jet traffic.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="725" LastEditDate="2016-01-07T10:46:56.427" LastActivityDate="2016-01-07T10:46:56.427" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="3011" PostTypeId="2" ParentId="3009" CreationDate="2014-12-10T23:12:51.263" Score="19" Body="&lt;p&gt;Just to add to casey's answer about the so called 'chemtrails', according to NASA's &lt;a href=&quot;http://science-edu.larc.nasa.gov/contrail-edu/science.php&quot;&gt;The Contrail Education Project&lt;/a&gt; webpage, that the actual amounts of anything else from a plane's exhaust is negligible, barely any amount at all - and these are just the products of the fuel burning (including soot) in the same process (with different hydrocarbons) as a car engine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NASA has even produced a &lt;a href=&quot;http://science-edu.larc.nasa.gov/contrail-edu/pdf/resources/Contrail_ID_Chart_English_2013_v18_copy.pdf&quot;&gt;Contrail Identification Chart and Formation Guide&lt;/a&gt; that visualises and further explains the atmospheric processes that casey explained.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Discovery News article &lt;a href=&quot;http://news.discovery.com/human/psychology/viral-video-claims-to-prove-chemtrails-conspiracy-140501.htm&quot;&gt;Viral Video Claims to Prove 'Chemtrails' Conspiracy&lt;/a&gt; (May 1, 2014) about a claim of 'irrefutable proof' of chemtrails, but that report was based on poor math skills used in reporting:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;So the alarming levels of barium that conspiracy theorist Jim Marrs cited as evidence of chemtrails was in fact a mistake created by a TV reporter’s poor math skills.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://contrailscience.com/chemical-analysis-of-contrails/&quot;&gt;Chemical Analysis of Contrails&lt;/a&gt; reports of testing of rainwater and snow, and found that the values for chemicals often cited by chemtrail conspiracy theorists (i.e. aluminium, barium, calcium, magnesium and titanium) were found to be no where near toic levels - in fact, given that the sources of these elements are both industrial and natural - there is no way that these can even be definitively linked to contrails.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As casey said and as many credible sources state that the evidence is that &lt;strong&gt;chemtrails do not exist&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-12-11T22:24:57.883" LastActivityDate="2014-12-11T22:24:57.883" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="3012" PostTypeId="2" ParentId="346" CreationDate="2014-12-11T00:51:00.820" Score="5" Body="&lt;p&gt;In order to confirm the snowball earth hypothesis, we'd need at least:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;A paleogeographic model which extends to greater than 650ma and has been shown be be conclusively accurate throughout that entire period. (i.e. one we can trust)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Sedimentation structures/patterns (or other paleoclimate proxy data), consistent with a glaciation event, tied into the same time period, from the north pole to the south pole&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="1294" LastActivityDate="2014-12-11T00:51:00.820" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3013" PostTypeId="2" ParentId="2997" CreationDate="2014-12-11T03:19:26.040" Score="5" Body="&lt;p&gt;Inertial instability is similar to the centrifugal instability in that we are looking at the stability of parcels to horizontal perturbations.  In the inertial case, however, the initial state is geostrophic balance rather than cyclostrophic balance.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Symmetric instability is the case where a parcel is inertially stable to horizontal perturbations and statically stable to vertical perturbations but unstable to perturbations between the horizontal and vertical.  An additional constraint is that the flow is symmetric and only varies in two dimensions.  This instability was also first examined as centrifugal instability, but with added baroclinity.  Conditional symmetric instability (CSI) is related to symmetric instability with the difference being that $\overline{\theta}^*_e$ rather than $\overline{\theta}$ surfaces are used to asses the instability. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For more information on these mesoscale instabilities, you can find information on them in Markowski and Richardson (2010) pages 49 (inertial instability) and 53 (symmetric instability).  Holton (4th ed, 2004) treats these instabilities on pages 204 (inertial oscillations) and 279 (symmetric instability).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Markwoski, P., and Y. Richardson, 2010: &lt;em&gt;Mesoscale meterology in midlatitudes&lt;/em&gt;. Wiley, 430 pp.&lt;br&gt;&#xA;Holton, J. R., 2004: &lt;em&gt;An introduction to dynamic meteorology&lt;/em&gt;. Elsevier, 4th ed., 535 pp.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2014-12-11T18:05:45.670" LastActivityDate="2014-12-11T18:05:45.670" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3015" PostTypeId="5" CreationDate="2014-12-11T09:24:20.050" Score="0" Body="&lt;p&gt;A climate model is a mathematical model used for studying the dynamics of climate systems or predicting future climates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For questions on the climate of a particular area use &lt;a href=&quot;/questions/tagged/climate&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged 'climate'&quot; rel=&quot;tag&quot;&gt;climate&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For questions on (man-caused) global warming or climate change use &lt;a href=&quot;/questions/tagged/climate-change&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged 'climate-change'&quot; rel=&quot;tag&quot;&gt;climate-change&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1109" LastEditorUserId="1109" LastEditDate="2014-12-11T09:58:53.243" LastActivityDate="2014-12-11T09:58:53.243" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3016" PostTypeId="4" CreationDate="2014-12-11T09:24:20.050" Score="0" Body="Mathematical models used for studying the dynamics of climate systems or predicting future climates." OwnerUserId="1109" LastEditorUserId="1109" LastEditDate="2014-12-11T09:58:56.837" LastActivityDate="2014-12-11T09:58:56.837" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3017" PostTypeId="2" ParentId="2897" CreationDate="2014-12-11T12:58:47.790" Score="2" Body="&lt;p&gt;Even though many researchers now recognise that the Silurian palaeoclimate show signs of large fluctuations - resulting in the carbon excursions, the mechanism behind the climatic shifts is not well understood.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recent research from Munnecke et al. 2014 (&lt;a href=&quot;http://www.gzn.uni-erlangen.de/en/palaeontology/staff/academic-staff/munnecke/research/palaeoenvironmental-reconstructions/silurian-climate/&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;) suggest that the carbon (and oxygen) isotope excursions that mainly affected low latitude palaeoenvironments, were probably due to climatic shifts between humid (low C) and arid (high C) climatic conditions. The possible consequences of these two climate regimes is shown below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/JqOzA.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the only certain climatic regimes that occurred was in the early Silurian, where 3 of the 7 'Early Palaeozoic Icehouse' (EPI) events occurred (&lt;a href=&quot;http://eprints.esc.cam.ac.uk/45/&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;).  Munnecke et al. 2010 (&lt;a href=&quot;http://www.geol.lu.se/PERSONAL/MLC/J23.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;) note that much of the Silurian is 'sandwiched' between the EPI and the greenhouse of the Devonian, possibly suggesting a prolonged transitional period between the 2 climatic regimes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some observations suggest that sea levels fluctuated very wildly, Munnecke et al. 2010 (&lt;a href=&quot;http://www.geol.lu.se/PERSONAL/MLC/J23.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;) states they were up to the order of 140 m.  This is partly related to recent oceanic circulation modelling performed by Servais et al. (&lt;a href=&quot;http://www.tandfonline.com/doi/full/10.1080/11035897.2013.876659#tabModule&quot; rel=&quot;nofollow noreferrer&quot;&gt;4&lt;/a&gt;) who state that the palaeogeography of the time (large northern ocean and the Gondwanan land mass at the south pole - see below) would have possible resulted in a halothermal circulation, rather than the modern day thermohaline circulation, essentially due to the restrictions a possible Mediterranean-like production of denser water at the lower latitudes (as indicated in the diagram above).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/lhgJC.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.scotese.com/newpage2.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, in summary, the oceanic-atmospheric interaction of the Silurian is considered to be unstable (&lt;a href=&quot;http://www.gzn.uni-erlangen.de/en/palaeontology/staff/academic-staff/munnecke/research/palaeoenvironmental-reconstructions/silurian-climate/&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;)(&lt;a href=&quot;http://www.geol.lu.se/PERSONAL/MLC/J23.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;), with oxic and anoxic regions uncertain (&lt;a href=&quot;http://www.tandfonline.com/doi/full/10.1080/11035897.2013.876659#tabModule&quot; rel=&quot;nofollow noreferrer&quot;&gt;4&lt;/a&gt;), but the effects were clearly seen with variations in the climate from humid to arid and large fluctuations in sea levels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.gzn.uni-erlangen.de/en/palaeontology/staff/academic-staff/munnecke/research/palaeoenvironmental-reconstructions/silurian-climate/&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;) Munnecke et al. 2014, &lt;a href=&quot;http://www.gzn.uni-erlangen.de/en/palaeontology/staff/academic-staff/munnecke/research/palaeoenvironmental-reconstructions/silurian-climate/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Silurian climate development&lt;/a&gt; &lt;em&gt;University of Nuremberg&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://eprints.esc.cam.ac.uk/45/&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;) Page, A., Zalasiewicz, J., Williams, M., Popov, L., 2007. &lt;a href=&quot;http://eprints.esc.cam.ac.uk/45/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Were transgressive black shales a&#xA;negative feedback modulating glacioeustasy in the Early Palaeozoic Icehouse?&lt;/a&gt; In:&#xA;Williams, M., Haywood, A.M., Gregory, F.J., Schmidt, D.N. (Eds.), Deep-Time&#xA;Perspectives on Climate Change: Marrying the Signal from Computer Models and&#xA;Biological Proxies: Special Publication of the Geological Society of London. The&#xA;Micropalaeontological Society, pp. 123–156&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.geol.lu.se/PERSONAL/MLC/J23.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;) Munnecke et al. 2010, &lt;a href=&quot;http://www.geol.lu.se/PERSONAL/MLC/J23.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ordovician and Silurian sea–water chemistry, sea level, and climate: A synopsis&lt;/a&gt; &lt;em&gt;Palaeogeography, Palaeoclimatology, Palaeoecology&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.tandfonline.com/doi/full/10.1080/11035897.2013.876659#tabModule&quot; rel=&quot;nofollow noreferrer&quot;&gt;4&lt;/a&gt;) Servais et al. 2014, &lt;a href=&quot;http://www.tandfonline.com/doi/full/10.1080/11035897.2013.876659#tabModule&quot; rel=&quot;nofollow noreferrer&quot;&gt;Possible oceanic circulation patterns, surface water currents and upwelling zones in the Early Palaeozoic&lt;/a&gt; &lt;em&gt;Special Issue:   EPGC - Early Palaeozic Global Change&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="87" LastEditDate="2014-12-11T13:27:55.550" LastActivityDate="2014-12-11T13:27:55.550" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3018" PostTypeId="1" AcceptedAnswerId="5405" CreationDate="2014-12-11T15:36:04.707" Score="20" ViewCount="2043" Body="&lt;p&gt;Someone just asked me if it would be practical to counter the rise of sea level by pumping water into storage on land. It struck me that if there is enough land below sea level, this would require construction of aquifers, but would not require using energy to pump the water as the destination of the water would be below its current level. But I have no idea how much land below sea level is available.&lt;/p&gt;&#xA;" OwnerUserId="1297" LastEditorUserId="28050" LastEditDate="2015-08-31T00:15:19.067" LastActivityDate="2017-02-15T22:37:25.297" Title="What fraction of dry land is below sea level?" Tags="|geophysics|ocean|climate|sea-level|water|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="3020" PostTypeId="1" CreationDate="2014-12-11T16:37:27.300" Score="13" ViewCount="2141" Body="&lt;p&gt;Based on a misunderstanding of another post, I prepared an estimate of how much water would be required to lower sea level by one meter. the main question would be: could this be stored on land?&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2024-02-05T04:34:55.197" Title="Would it be geographically feasible to store water on land to counteract sea level rise?" Tags="|sea-level|topography|" AnswerCount="4" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="3021" PostTypeId="2" ParentId="3020" CreationDate="2014-12-11T16:38:38.873" Score="13" Body="&lt;p&gt;Using the &lt;a href=&quot;http://www.ngdc.noaa.gov/mgg/global/relief/ETOPO1/docs/ETOPO1.pdf&quot; rel=&quot;noreferrer&quot;&gt;eTopo1 data&lt;/a&gt; Eakins and Sharman has calculated a hypsographic curve for the earth. In the elevation span between + 6 to -6 m they found that land area will change by 396 000 km&lt;sup&gt;2&lt;/sup&gt; per meter sea level change. In the range -7 to -51 m below current sea level the land area will change by 251 000 km&lt;sup&gt;2&lt;/sup&gt; per meter sea level. Thus to get an area the size of Zimbabwe (391 000 km&lt;sup&gt;2&lt;/sup&gt;) or Norway (385 000 km&lt;sup&gt;2&lt;/sup&gt;) (data from &lt;a href=&quot;http://data.worldbank.org/indicator/AG.SRF.TOTL.K2&quot; rel=&quot;noreferrer&quot;&gt;the World bank&lt;/a&gt;) sea level will currently have to be lowered by 1 m. Since the ocean surface is about 360 000 000 km&lt;sup&gt;2&lt;/sup&gt; (e.g. &lt;a href=&quot;http://hypertextbook.com/facts/1997/EricCheng.shtml&quot; rel=&quot;noreferrer&quot;&gt;The Physics factbook&lt;/a&gt;) this would mean a total of about 360 000 km&lt;sup&gt;3&lt;/sup&gt; of water which in turn is comparable to the Caspian Sea (371 000 km&lt;sup&gt;3&lt;/sup&gt; according to a &lt;a href=&quot;http://en.wikipedia.org/wiki/List_of_lakes_by_volume&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia compilation&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So where does that lead? Clearly adding a Caspian Sea somewhere on land is not an easy task so the question is how much land need to be gained and where? Remember that all coasts are not the same, topographically.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a side point, the Greenland ice sheet contains enough water to raise sea level by about 7 m. Hence the ongoing warming is a far more problematic issue when it comes to sea level change and counteracting this volume would be 7 times more challenging than the calculation made above. That is a sobering perspective.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Reference&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Eakins, B.W. and G.F. Sharman. &lt;em&gt;Hypsographic Curve of Earth's Surface from ETOPO1&lt;/em&gt;, NOAA National Geophysical Data Center, Boulder, CO, 2012 &lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="725" LastEditDate="2014-12-13T08:20:08.300" LastActivityDate="2014-12-13T08:20:08.300" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3022" PostTypeId="2" ParentId="3008" CreationDate="2014-12-11T17:07:54.030" Score="4" Body="&lt;p&gt;As per @Richard suggestion, I think the best answer comes from &lt;a href=&quot;http://www.dune-pyla.com/en/construction-of-the-great-dune-of-pyla-history.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;dune-pyla.com&lt;/a&gt;. They provide a complete explanation of the evolution of the dune and a couple of great summary figures:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/4DDAl.gif&quot; alt=&quot;Paleosol levels of the Dune&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems that the material comes in large part from the Banc d'Arguin to the west through aeolian transport. The sand from the bank and adjacent areas is related to the material from the river Garonne to the north.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/NN3WB.jpg&quot; alt=&quot;Evolution of the Dune since 8000 B.P.&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Part of the reason for the height is that they covered the preexisting Dune de La Grave with a pine forest during the XIX century to stabilize the sand and then the forest was covered by another additional 20-30 meters of sand. The dune is still migrating east at an average rate of around 7-8 m/year and burying the surrounding forest as it migrates. &lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2014-12-11T17:07:54.030" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3023" PostTypeId="2" ParentId="2583" CreationDate="2014-12-11T19:14:27.447" Score="6" Body="&lt;p&gt;Changes in the Earth's rate of rotation is measured by the International Earth Rotation and Reference Systems Service (IERS) using &lt;a href=&quot;http://www.iers.org/IERS/EN/Science/Techniques/techniques.html&quot;&gt;observational techniques&lt;/a&gt;. They publish daily the rate and orientation of the Earth's rotation, and publish near-term forecasts (of great practical use if you are launching satellites into orbit.) Mass movements in the atmosphere due to weather can change the rotation. I know papers written by &lt;a href=&quot;http://scienceandtechnology.jpl.nasa.gov/people/r_gross/&quot;&gt;Richard Gross&lt;/a&gt; at JPL have discussed methods used to examine rotation/earthquake interactions - you can try looking there.    &lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-12-11T19:14:27.447" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3025" PostTypeId="1" AcceptedAnswerId="3028" CreationDate="2014-12-11T20:54:31.647" Score="12" ViewCount="247" Body="&lt;p&gt;First of all, this question is &lt;strong&gt;not&lt;/strong&gt; about the &lt;a href=&quot;https://earthscience.stackexchange.com/questions/3009/why-arent-there-more-questions-and-concerns-about-chemtrails/3011&quot;&gt;conspiracy theory based chemtrails&lt;/a&gt; as in the linked question, from the answers there and from the question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2980/equation-for-predicting-contrail-formation&quot;&gt;Equation for predicting contrail formation&lt;/a&gt; I understand how contrails form and how they could be predicted.  Also, the evidence (as in the links and discussions within the answers to the linked questions, reveal that much of the chemistry of contrails is water and some soot.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Observations of contrails (from the ground and from satellite imagery) in the webpage &lt;a href=&quot;http://cimss.ssec.wisc.edu/wxwise/class/contrail.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Contrails&lt;/a&gt; by Professor Steve Ackerman of the University of Wisconsin, he notes that contrails&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;rapidly dissipate or spread horizontally into an extensive thin cirrus layer.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and also states that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;NASA and the DOE are sponsoring a research program to study the impact contrails have on atmospheric chemistry, weather and climate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Given it is long known that clouds affect the atmospheric radiation budget, &lt;strong&gt;is there evidence of atmospheric radiative effects of contrails?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-10-14T03:36:52.917" Title="What atmospheric radiative effects, if any, do contrails cause?" Tags="|atmosphere|clouds|human-influence|atmosphere-modelling|atmospheric-radiation|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="3027" PostTypeId="2" ParentId="2177" CreationDate="2014-12-12T10:41:39.143" Score="8" Body="&lt;p&gt;The main reason for Sacramento's warmth compared to some other cities at the same latitude is, like in many cases, due to the city's surrounding topography, as can be seen in the topographic map below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/lk8KQ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://en.wikipedia.org/wiki/Geography_of_California&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia: Geography of California&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In regards to the climate of Sacramento, it is probably better to consider why it is &lt;em&gt;seasonally&lt;/em&gt; warmer than cities on the same latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sacramento is located in a regionally low elevation Great Valley (also Central Valley) (&lt;a href=&quot;http://www.dfg.ca.gov/biogeodata/atlas/pdf/Clim_12b_web.pdf&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;), in between two roughly parallel mountains ranges that converge in the north of the Valley in the Klamath Ranges. The Coastal Range on the west and the Sierra Nevada to the east (&lt;a href=&quot;http://www.wrcc.dri.edu/narratives/california/&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://www.meteorologyclimate.com/koppenclassification.htm&quot; rel=&quot;noreferrer&quot;&gt;Köppen climate classification&lt;/a&gt; for Sacramento is &lt;code&gt;Csa&lt;/code&gt;, which is defined as a Mediterranean environment with hot summers (&lt;a href=&quot;http://www.dfg.ca.gov/biogeodata/atlas/pdf/Clim_12b_web.pdf&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;). The Coastal Range largely shields the city (and the Valley) from the climate (especially much of the humidity) of the Maritime climate to the west, and the Continental climate to the east (&lt;a href=&quot;http://www.wrcc.dri.edu/narratives/california/&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;).  Essentially, according to the WRCC, the climate of the Valley (including Sacramento) is intermediate between the climates either side of the bordering ranges (&lt;a href=&quot;http://www.wrcc.dri.edu/narratives/california/&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The very cold winters that can occur in the Continental climate are blocked by the Sierra Nevada.  Even if cold air does get over the mountain, the air warms as it compresses as descends into the Valley, and hence is milder when it reaches the Valley (&lt;a href=&quot;http://www.wrcc.dri.edu/narratives/california/&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In regards to the Urban Heat Island, The US EPA (&lt;a href=&quot;http://www.epa.gov/heatisland/pilot/archives/Sacramento.pdf&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;) performed measurements and observations of Sacramento between 1998-2002, revealing that there is an urban heat island of the order of an average increase in temperature in the city of 0.5-1°C (0.9-1.8°F) compared to the surrounding non-urban areas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.dfg.ca.gov/biogeodata/atlas/pdf/Clim_12b_web.pdf&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;) Kauffman, E. &lt;a href=&quot;http://www.dfg.ca.gov/biogeodata/atlas/pdf/Clim_12b_web.pdf&quot; rel=&quot;noreferrer&quot;&gt;Climate and Topography&lt;/a&gt; &lt;em&gt;California Department of Fish and Wildlife&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.wrcc.dri.edu/narratives/california/&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;) Western Regional Climate Centre (WRCC), &lt;a href=&quot;http://www.wrcc.dri.edu/narratives/california/&quot; rel=&quot;noreferrer&quot;&gt;Climate of California&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.epa.gov/heatisland/pilot/archives/Sacramento.pdf&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;) &lt;a href=&quot;http://www.epa.gov/heatisland/pilot/archives/Sacramento.pdf&quot; rel=&quot;noreferrer&quot;&gt;U.S. EPA Urban Heat Island Pilot Project: Profile of Sacramento&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-12-12T10:41:39.143" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3028" PostTypeId="2" ParentId="3025" CreationDate="2014-12-12T11:51:33.870" Score="11" Body="&lt;p&gt;We had a surprising opportunity to study this very question during the period of September 11-14, 2001, when all air traffic was grounded across the United States.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The research was inconclusive, but they found that there was a 1.8 degree celsius increase across the US during this time frame compared to the three days before and after that time frame.  However, this shift may have been coincidental.  It was found by others that this temperature shift was within the normal range for the time of year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ultimately, the question of whether these high-level clouds impact the weather and temperatures is still an open debate.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The source for this answer is from a &lt;a href=&quot;http://www.nature.com/news/2008/081231/full/news.2008.1335.html&quot;&gt;Nature.com article&lt;/a&gt;.  However, they take their sources from the original research:&lt;br/&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://dx.doi.org/10.1038/418601b&quot;&gt;Travis, Carleton, &amp;amp; Lauritsen&lt;/a&gt; showing contrails have an effect &lt;br/&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://dx.doi.org/10.1029/2008GL036108&quot;&gt;Hong, et al&lt;/a&gt; showing contrails do not have an effect&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="330" LastEditorUserId="330" LastEditDate="2014-12-12T12:03:23.437" LastActivityDate="2014-12-12T12:03:23.437" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3029" PostTypeId="1" AcceptedAnswerId="3053" CreationDate="2014-12-12T12:50:05.650" Score="13" ViewCount="952" Body="&lt;p&gt;Is there a scientific definition of a continent? Is there an academic reference for such a definition? There's a tendency to correlate with tectonic plates, but of course lots of plates don't have continents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I keep running across &quot;by convention&quot; and &quot;landmass&quot; but I don't see anything really definitive, or anything academic. I've got the whole Pangaea/Gondwana/craton/shield/continental crust/oceanic crust/plate tectonics fine, but this simple question is pretty vague. &lt;/p&gt;&#xA;" OwnerUserId="1303" LastEditorUserId="342" LastEditDate="2014-12-15T16:48:58.063" LastActivityDate="2014-12-15T16:48:58.063" Title="What is the definition of a continent?" Tags="|plate-tectonics|structural-geology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="3030" PostTypeId="2" ParentId="3006" CreationDate="2014-12-12T16:15:01.110" Score="7" Body="&lt;p&gt;The answer depends a lot on what you mean by &quot;excluding shale oil&quot;.  Tight oil production, commonly referred to as &quot;shale oil&quot; is &lt;a href=&quot;http://www.eia.gov/todayinenergy/detail.cfm?id=15571&quot; rel=&quot;nofollow noreferrer&quot;&gt;about 4 million barrels per day currently (2014)&lt;/a&gt;, compare to almost none in 2005.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Canadian oil sands production is at 2 millon barrels per day, compare to about 700,000 per day in 2005.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So compare to 2005, tight oil (shale oil) and oil sands production is up about 5 million barrels per day.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now look at total world oil production:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/S7NiW.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the graph it can been seen that subtracting out the 5 million barrels/day of unconventional production, world production is somewhat below the 2005 level. (&lt;a href=&quot;http://www.eia.gov/totalenergy/data/monthly/pdf/sec11_5.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Quantitative values&lt;/a&gt; were 73.9 M bbl/day in 2005; 76.9 M bbl/day in first 8 months of 2014)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With the expectation that tight oil and oil sands production will increase in share of the production, it is entirely possible that the peak in conventional production has already occurred.  &lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2014-12-12T16:31:49.867" LastActivityDate="2014-12-12T16:31:49.867" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3032" PostTypeId="1" CreationDate="2014-12-12T21:57:04.203" Score="10" ViewCount="119" Body="&lt;p&gt;The gravitational binding energy of the Earth is $2×10^{32}  J $, so the same amount of energy must have been released during the Earth's history. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://books.google.com.eg/books?id=rf419f-p4D8C&amp;amp;pg=PA234&amp;amp;lpg=PA234&amp;amp;dq=earth%20internal%20energy%201031&amp;amp;source=bl&amp;amp;ots=vOBvhyjgZu&amp;amp;sig=Fr63wbCRm-LdSSFFXilKoMplc9M&amp;amp;hl=ar&amp;amp;sa=X&amp;amp;ei=fEuLVPrDNIb9Uo_MgpAB&amp;amp;ved=0CCQQ6AEwAQ#v=onepage&amp;amp;q=earth%20internal%20energy%201031&amp;amp;f=false&quot;&gt;this&lt;/a&gt; and &lt;a href=&quot;https://books.google.com.eg/books?id=qyN6_83vz2MC&amp;amp;pg=PA109&amp;amp;lpg=PA109&amp;amp;dq=earth%20energy%201031&amp;amp;source=bl&amp;amp;ots=fFzkC7Jl2r&amp;amp;sig=ey04DuzETjpfWDPHFRnmaEs4ew4&amp;amp;hl=ar&amp;amp;sa=X&amp;amp;ei=mkuLVOSaJ4K0UYPfgqgF&amp;amp;ved=0CD0Q6AEwBA#v=onepage&amp;amp;q=earth%20energy%201031&amp;amp;f=false&quot;&gt;this&lt;/a&gt;, the current internal energy of the Earth is ~ $1.5×10^{31} J$, and according to &lt;a href=&quot;https://books.google.com.eg/books?id=4ey5BAAAQBAJ&amp;amp;pg=PA23&amp;amp;lpg=PA23&amp;amp;dq=earth%20internal%20energy%201031&amp;amp;source=bl&amp;amp;ots=Zsqn2sk7sI&amp;amp;sig=pKqC0LMcAHHJ7QpcjLxH0HW7oSM&amp;amp;hl=ar&amp;amp;sa=X&amp;amp;ei=LUWLVP-NBcKvU4Lbg5AM&amp;amp;ved=0CEYQ6AEwBg#v=onepage&amp;amp;q=earth%20internal%20energy%201031&amp;amp;f=false&quot;&gt;this&lt;/a&gt; source, the amount of heat loss due to outward radiation by the Earth during the entire lifetime of the planet is about $0.45×10^{31}  J $. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, by adding those two numbers we get the Earth internal energy + energy radiated = ~ $2×10^{31}  J $, which is an order of magnitude less than what we should expect. &#xA;We are also ignoring the fact that 50-90% of the current internal energy of the Earth is due to radioactive decay. So where did the rest of the energy go ?&lt;/p&gt;&#xA;" OwnerUserId="1305" LastActivityDate="2014-12-12T21:57:04.203" Title="Where did the energy released due to gravitational binding energy of the Earth go?" Tags="|geophysics|earth-history|geothermal-heat|planetary-formation|" AnswerCount="0" CommentCount="2" ClosedDate="2014-12-26T00:25:06.253" ContentLicense="CC BY-SA 3.0" />
  <row Id="3033" PostTypeId="2" ParentId="2249" CreationDate="2014-12-13T00:34:11.087" Score="10" Body="&lt;p&gt;There has been some considerable modelling about this particular scientific issue, as it is considered important to understand Venusian tectonics to be able to get a better understanding of Earth tectonics (&lt;a href=&quot;http://geology.gsapubs.org/content/42/1/95.short&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, in answer to your question, is Venus tectonically active, the answer from current research suggests that it is not - but not at the moment, especially not like Earth. Much of the research refers to Venus as currently possessing a &quot;stagnant-lid&quot; single plate (&lt;a href=&quot;http://geology.gsapubs.org/content/42/1/95.short&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;),(&lt;a href=&quot;http://anquetil.colorado.edu/szhong/papers/Huang_etal_EPSL_2013.pdf&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;), (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/93JE01775/abstract&quot; rel=&quot;noreferrer&quot;&gt;5&lt;/a&gt;).  The tectonic-like features found on Venus have not been observed to 'fit' a global pattern that would suggest a 'mobile-lid' tectonic regime like that of Earth (&lt;a href=&quot;http://geology.gsapubs.org/content/42/1/95.short&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;). Much of the recent research has not really focused much on the differences between Earth and Venus - including, the Moon, liquid water and differences in rotation, but rather focuses on what observations of orbiting spacecraft, such as Magellan and the Venus Explorer have revealed and what models based on these have deduced.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recent research has painted a picture that the answer to this question is considerably more complex than would justify a 'yes' or 'no' answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Modelling from gravity and topographic anomalies observed by several of the space craft that we have sent to Venus suggest that many of these features are derived from 'hotspot' upwelling mantle plumes where partial melting could occur (&lt;a href=&quot;http://anquetil.colorado.edu/szhong/papers/Huang_etal_EPSL_2013.pdf&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;).  This is supported by an example of a recent re-evaluation of earlier observations of tectonic-like features on Venus was performed by McGovern et al. (2014) (&lt;a href=&quot;http://geology.geoscienceworld.org/content/42/1/59.abstract&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;) of Magellan images, using stereo radargrammatic images, of the graben-like structures that extend from the Venusian shield volcanoes reveal that they, alongside the radial dike emplacements, are accounted for by magma reservoir expansion (&lt;a href=&quot;http://geology.gsapubs.org/content/42/1/95.short&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Models reported by Huang et al. 2014 (&lt;a href=&quot;http://anquetil.colorado.edu/szhong/papers/Huang_etal_EPSL_2013.pdf&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;) also suggest that Venus has a very thick lithosphere compared to that of Earth, which would support the high topography noted for Venus (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/93JE01775/abstract&quot; rel=&quot;noreferrer&quot;&gt;5&lt;/a&gt;).  Related to this is that in deformation experiments, Azuma et al. 2014 (&lt;a href=&quot;http://www.nature.com/srep/2014/140318/srep04403/full/srep04403.html?message-global=remove&amp;amp;WT.ec_id=SREP-20140325&quot; rel=&quot;noreferrer&quot;&gt;4&lt;/a&gt;) suggest that is a mechanical decoupling of the Venusian crust and the mantle convection (as shown in the diagram below (&lt;a href=&quot;http://www.nature.com/srep/2014/140318/srep04403/full/srep04403.html?message-global=remove&amp;amp;WT.ec_id=SREP-20140325&quot; rel=&quot;noreferrer&quot;&gt;4&lt;/a&gt;)).  Huang et al. (&lt;a href=&quot;http://anquetil.colorado.edu/szhong/papers/Huang_etal_EPSL_2013.pdf&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;) models also have found that Venus cannot have a weak asthenosphere in the way that Earth does.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/gNxZn.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, coming back to what I meant about not being tectonically active 'at the moment' in the first paragraph.  This comes from the observation that the entire planet seems to have been resurfaced approximately 750 million years ago, evidenced through the amount of craters and other features (&lt;a href=&quot;http://geology.gsapubs.org/content/42/1/95.short&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;).  This has lead to some researchers, such as Turcotte, 1993 (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/93JE01775/abstract&quot; rel=&quot;noreferrer&quot;&gt;5&lt;/a&gt;) to suggest that tectonic activity on Venus is episodic. The process is hypothesised by Head, 2014 (&lt;a href=&quot;http://geology.gsapubs.org/content/42/1/95.short&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;) as comprising 3 stages:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;A relatively short phase of intense tectonism, as indicated by the tesserae, high plateaus, plains deformation and coronae - Turcotte (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/93JE01775/abstract&quot; rel=&quot;noreferrer&quot;&gt;5&lt;/a&gt;) theorises that the formation of coronae could be an indication of a new episode of tectonism.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;A relatively short phase of intense volcanism, with minor subsidence and deformation.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;A long period of network rifting (graben formation, modelled to be hotspot induced (&lt;a href=&quot;http://geology.geoscienceworld.org/content/42/1/59.abstract&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;)) and volcanism.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Recent modelling by Gillman and Tackley (2014) (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2013JE004505/abstract&quot; rel=&quot;noreferrer&quot;&gt;6&lt;/a&gt;) provide a possible mechanism to the 3 stage process by Head, 2014 (&lt;a href=&quot;http://geology.gsapubs.org/content/42/1/95.short&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;).  Gillman and Tackley's models suggest that the thick Venusian atmospheric surface temperature provides a boundary layer for mantle convection models, in particular, the atmospheric water vapor pressure which is sensitive to volcanic activity.  They suggest that cooler surface temperatures result in a 'mobile-lid' type of tectonic regime, that is until the temperature rises again causing a return to the stagnant-lid one plate scenario that we observe today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://geology.gsapubs.org/content/42/1/95.short&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;) Head, 2014, &lt;a href=&quot;http://geology.gsapubs.org/content/42/1/95.short&quot; rel=&quot;noreferrer&quot;&gt;The geologic evolution of Venus: Insights into Earth history&lt;/a&gt; &lt;em&gt;Geology&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://anquetil.colorado.edu/szhong/papers/Huang_etal_EPSL_2013.pdf&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;) Huang et al. 2013, &lt;a href=&quot;http://anquetil.colorado.edu/szhong/papers/Huang_etal_EPSL_2013.pdf&quot; rel=&quot;noreferrer&quot;&gt;Constraints of the topography, gravity and volcanism on Venusian mantle&#xA;dynamics and generation of plate tectonics&lt;/a&gt;, &lt;em&gt;Earth and Planetary Science Letters&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://geology.geoscienceworld.org/content/42/1/59.abstract&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;) McGovern et al. 2014, &lt;a href=&quot;http://geology.geoscienceworld.org/content/42/1/59.abstract&quot; rel=&quot;noreferrer&quot;&gt;New constraints on volcano-tectonic evolution of large volcanic edifices on Venus from stereo topography–derived strain estimates&lt;/a&gt; &lt;em&gt;Geology&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.nature.com/srep/2014/140318/srep04403/full/srep04403.html?message-global=remove&amp;amp;WT.ec_id=SREP-20140325&quot; rel=&quot;noreferrer&quot;&gt;4&lt;/a&gt;) Azuma et al. 2014, &lt;a href=&quot;http://www.nature.com/srep/2014/140318/srep04403/full/srep04403.html?message-global=remove&amp;amp;WT.ec_id=SREP-20140325&quot; rel=&quot;noreferrer&quot;&gt;Rheological decoupling at the Moho and implication to Venusian tectonics&lt;/a&gt;, &lt;em&gt;Nature&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/93JE01775/abstract&quot; rel=&quot;noreferrer&quot;&gt;5&lt;/a&gt;) Turcotte, 1993, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/93JE01775/abstract&quot; rel=&quot;noreferrer&quot;&gt;An episodic hypothesis for Venusian tectonics&lt;/a&gt;, &lt;em&gt;Journal of Geophysical Rsearch&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2013JE004505/abstract&quot; rel=&quot;noreferrer&quot;&gt;6&lt;/a&gt;) Gillman and Tackley, 2014, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2013JE004505/abstract&quot; rel=&quot;noreferrer&quot;&gt;Atmosphere/mantle coupling and feedbacks on Venus&lt;/a&gt;, &lt;em&gt;Journal of Geophysical Research&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-12-13T00:34:11.087" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3034" PostTypeId="2" ParentId="3020" CreationDate="2014-12-13T02:20:03.460" Score="3" Body="&lt;p&gt;Pump the water somewhere it will freeze and remain so. Who's buying?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question would be if it's &lt;em&gt;economically&lt;/em&gt; viable. If we can put man on the moon and send probes outside our solar system I see no reason why we can't perform the basic task of freezing water and putting it &lt;strike&gt; back where it belongs&lt;/strike&gt; where we want it. &lt;em&gt;Only at the precipice do we change&lt;/em&gt;. When rising sea levels begin to threaten &lt;em&gt;all&lt;/em&gt; human life on Earth we might just do something about it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geographically it would be difficult to make a reservoir large enough that didn't just leak back into the water table. Mining a cistern into faultless, living granite might be a toss up as to the energy/money required compared to just pumping that water to a permafrost area; manual re-glaciation ($$$). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anything reasonable is feasible; how many zeros in your check book? That silly end-of-the-Earth movie where they go to the core and save the world comes to mind. &lt;em&gt;One trillion dollars? Will you take a check?&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="654" LastActivityDate="2014-12-13T02:20:03.460" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="3035" PostTypeId="2" ParentId="3020" CreationDate="2014-12-13T06:37:12.487" Score="4" Body="&lt;p&gt;The best solution to this type of problem would be to desalinate all excess water at shorelines.  This could be done with desalination plants that use their own energy produced from tidal/wave generators.  There are plenty of empty reservoirs in the world that would be happy to take any excess water that is desalinated.  I'm assuming if we can build transcontinental pipelines for oil.. we can do it for water.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2014-12-13T06:37:12.487" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3036" PostTypeId="1" AcceptedAnswerId="3052" CreationDate="2014-12-13T13:28:00.270" Score="12" ViewCount="407" Body="&lt;p&gt;In the article &lt;a href=&quot;http://www.geo.arizona.edu/~reiners/geos474-574/Moorbath2005AG.pdf&quot;&gt;Oldest rocks, earliest life, heaviest impacts, and the&#xA;Hadean–Archaean transition&lt;/a&gt; (Moorbath, 2005), the author states (based on previous referenced research) that the $\ce{^13C}$ depletion previously stated as being a biotracer of the presence of early life in the metamorphosed sedimentary Archaean aged (~3.8 billion year old) rocks found in Isua, Greenland is disputed, by what the author states as being a result of&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;serious metamorphic&#xA;  and tectonic complications for a biogenic&#xA;  interpretation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Hence, the presence of the traces of very early life at that location (and age) are not confirmed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, &lt;strong&gt;what is the age of the earliest traces of life on Earth?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="87" LastEditDate="2014-12-15T07:45:05.717" LastActivityDate="2016-05-04T09:38:12.330" Title="What is the age of the earliest traces of life on Earth?" Tags="|earth-history|paleontology|metamorphism|biogeochemistry|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3037" PostTypeId="1" CreationDate="2014-12-14T02:23:27.347" Score="1" ViewCount="63" Body="&lt;p&gt;I don't know how to find the distance of the epicenter from New York 9:00UTC, Mexico city 9:00UTC and Seattle 9:00UTC&lt;/p&gt;&#xA;" OwnerUserId="1308" LastEditorUserId="115" LastEditDate="2014-12-18T17:46:53.993" LastActivityDate="2014-12-18T17:46:53.993" Title="How to find the distance from the epicenter?" Tags="|earthquakes|" AnswerCount="0" CommentCount="2" ClosedDate="2014-12-14T04:06:10.153" ContentLicense="CC BY-SA 3.0" />
  <row Id="3038" PostTypeId="1" CreationDate="2014-12-14T03:37:48.710" Score="11" ViewCount="3238" Body="&lt;p&gt;It is reasonably well known that the North American tectonic plate includes a portion of eastern Siberia.  What is often typical in plate tectonic maps is that the actual plate boundary is often drawn with a degree of uncertainty, for example, the map below from the &lt;a href=&quot;http://earthobservatory.nasa.gov/Features/Tectonics/&quot;&gt;NASA Earth Observatory&lt;/a&gt; website is very scant on details of this particular boundary, at times, the plat boundary is referred to as 'diffuse'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZkE5U.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What tectonic structures exist on the Eurasian - North American plate boundary in eastern Siberia?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-12-14T20:31:46.680" LastActivityDate="2014-12-14T23:47:34.693" Title="What tectonic structures exist on the Eurasian - North American plate boundary in eastern Siberia?" Tags="|geophysics|plate-tectonics|tectonics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3039" PostTypeId="1" CreationDate="2014-12-14T04:10:54.937" Score="9" ViewCount="986" Body="&lt;p&gt;Growing up, when looking in textbooks and other references about plate tectonics, there was always the Indo-Australian (or Indian-Australian) plate, such as shown below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/adrqg.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image source: &lt;a href=&quot;http://www.yosemite.ca.us/library/geologic_story_of_yosemite/rocks.html&quot; rel=&quot;noreferrer&quot;&gt;The Geologic Story of Yosemite National Park (1987) by N. King Huber&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But, recently it has been recognised that there are separate Indian and Australian plates, such as shown below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/TsRlt.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image source: &lt;a href=&quot;http://eqseis.geosc.psu.edu/~cammon/HTML/Classes/IntroQuakes/Notes/plate_tect01.html&quot; rel=&quot;noreferrer&quot;&gt;An Introduction to&#xA;Plate Tectonics&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This would make sense given the differences in the collisional history of the two landmasses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What tectonic structures delineate the split between the Australian and Indian tectonic plates?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-12-14T04:23:23.697" LastActivityDate="2014-12-14T04:57:50.603" Title="What tectonic structures delineate the split between the Australian and Indian tectonic plates?" Tags="|geophysics|plate-tectonics|tectonics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3040" PostTypeId="2" ParentId="3039" CreationDate="2014-12-14T04:57:50.603" Score="3" Body="&lt;p&gt;The structures are not mature or well defined and deformation was thought to be diffused, i.e., distributed over a large area. Earthquakes such as the M8.6 2012 Indian Ocean earthquake (largest strike-slip earthquake on record) appear to accommodate some, if not all, of the deformation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seafloor geodesy is relatively a new field. Most studies are limited to areas near the coast, e.g., US (Cascadia), Japan etc.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastActivityDate="2014-12-14T04:57:50.603" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3041" PostTypeId="1" AcceptedAnswerId="3042" CreationDate="2014-12-14T06:32:53.253" Score="37" ViewCount="3418" Body="&lt;p&gt;Anthropogenic-sourced greenhouse gases are commonly cited as the main source for human-caused climate change. However, something that I never see discussed is the actual heat produced by human activities. It could be that it's negligible, but I'm still curious to see quantitative data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, a running engine in a vehicle produces $\ce{CO2}$ due to fuel combustion, but the engine also produces heat. What about heat produced from ovens, fireplaces, incandescent lighting, etc.? Ignoring the carbon footprint of such activities, can the heat alone be sufficient to affect the atmosphere on a global scale?&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="543" LastEditorDisplayName="user889" LastEditDate="2016-05-16T23:18:07.300" LastActivityDate="2023-08-03T11:57:21.597" Title="How does anthropogenic heating affect global warming?" Tags="|atmosphere|climate-change|thermodynamics|radiative-transfer|" AnswerCount="4" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="3042" PostTypeId="2" ParentId="3041" CreationDate="2014-12-14T07:43:41.840" Score="29" Body="&lt;p&gt;A recent study by Chen et al. (2014) in the article &lt;a href=&quot;https://www.jstage.jst.go.jp/article/jmsj/92A/0/92A_2014-A10/_pdf&quot; rel=&quot;noreferrer&quot;&gt;Anthropogenic Heat Release: Estimation of Global Distribution and&#xA;Possible Climate Effect&lt;/a&gt; defined the heat release as you described as being &lt;strong&gt;Anthropogenic heat release&lt;/strong&gt; (AHR), and has it basis as a product of economic prosperity, which leads to energy usage and excess heat produced - usually in large cities globally - this is sometimes referred to as 'waste heat'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In their research, Chen et al  report on an earlier global estimate made by Chen and Shi, 2012:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Globally, the estimated AHR is 0.03 Wm$^{-2}$&lt;/li&gt;&#xA;&lt;li&gt;Over land, this average becomes 0.10 Wm$^{-2}$&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Although, globally, these amounts are considerably less than that from $\ce{CO2}$ emissions, they still add to the problem - especially as the rate of urbanisation, hence the use of heat generating appliances is increasing rapidly, this value will become more significant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However on a regional scale, over large cities for example, such as Tokyo, the effects of AHR are more profound.  In and around the region around Tokyo city, the AHR can exceed 400 Wm$^{-2}$.  So what are the consequences of this flux?  Most of it causes regional effects, in particular (from Chen et al.):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Can influence urban climates and is a significant contributor to the urban heat island, which amongst other things can &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2568/how-do-urban-areas-affect-rain&quot;&gt;affect regional rain patterns&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Can affect the dynamics and thermodynamics of urban boundary layers.&lt;/li&gt;&#xA;&lt;li&gt;Can influence the reaction rates and types of emitted aerosol and particulate species.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;All of which have a compounding effect in the regional and to a lesser degree, global environment, that Chen et al. attribute to as being a cause of a 1-2K temperature rise in high altitude areas in Eurasia and North America and as a disrupting influence in global atmospheric circulation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit 28/2/2016: There is an interesting blog post about a similar phenomenon: &lt;a href=&quot;http://blogs.agu.org/geospace/2016/02/23/dubai-construction-alters-local-climate/&quot; rel=&quot;noreferrer&quot; title=&quot;Dubai construction alters local climate&quot;&gt;Dubai construction alters local climate&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Additional references&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Chen, B., and G.-Y. Shi, 2012: Estimation of the distribution&#xA;of global anthropogenic heat flux. Atmos. Oceanic&#xA;Sci. Lett., 5, 108–112.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-02-28T04:41:18.090" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3043" PostTypeId="2" ParentId="3041" CreationDate="2014-12-14T10:15:51.507" Score="15" Body="&lt;p&gt;Disclamer: I am not an atmospheric or climate scientist; corrections are welcome if I have anything wrong.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Human heat production&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;According to the &lt;a href=&quot;http://www.iea.org/publications/freepublications/publication/key-world-energy-statistics-2014.html&quot;&gt;IEA&lt;/a&gt;, world primary energy consumption in 2012 was 13370 million tons of oil equivalent, which works out to being $5.6 \times 10^{20}$ Joules. Averaged over a year, this equates to $17.8\,\mathrm{TW}$. Wind, solar, etc., are a negligible part of this, but it does include a small but noticable amount of hydro and biomass. Strictly speaking, all of the hydro and some of the biomass should be excluded as they are simply a short-term &quot;reuse&quot; of energy that has already arrived from the sun, and not &quot;new energy&quot;. Let us use the figure above but treat it as an upper bound.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The area of the earth is $5.1 \times 10^{14}\, \mathrm{m^2}$(source: Wolfram Alpha), which means that the figure above comes out to $0.033\,\mathrm{Wm^{-2}}$, a comfortingly close match to the figure given in the literature in Sabre Tooth's answer.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Energy from the sun&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;According to the Wikipedia page &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_energy_budget&quot;&gt;Earth's energy budget&lt;/a&gt;&quot;, average solar insolation on the surface of the earth, taking into account day and night, summer and winter, is around $240\,\mathrm{Wm^{-2}}$. The figure that we should use is higher than this, as some is absorbed in the atmosphere and contributes to warming, but let us treat this as a lower bound. Multiplying by the surface area of the planet gives us an incoming energy flux of $1.22 \times 10^{17} \, \mathrm{W}$, or 122 petawatts.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Comparisons&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Total human heat production, then, is in the order of 0.01% of the energy from space, and as such one might consider it negligible. By contrast, the total energy imbalance that results in global warming - &lt;em&gt;including&lt;/em&gt; any effect from anthropogenic heating - is &lt;a href=&quot;http://www.giss.nasa.gov/research/briefs/hansen_16/&quot;&gt;estimated&lt;/a&gt; to be approx 300 TW, or 20 times the total anthropogenic heat output.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(As an aside: Initially when writing this I thought &quot;human fuel use is 5% of the planet's energy imbalance - that's significant!&quot;. But of course the greenhouse effect results in an imbalance that is a &lt;em&gt;proportion&lt;/em&gt; of the total radiated energy, and human energy makes an insignificant difference to that total radiated energy.)&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2014-12-14T10:15:51.507" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3045" PostTypeId="1" CreationDate="2014-12-14T17:31:58.713" Score="15" ViewCount="1788" Body="&lt;p&gt;I was thinking it could have been a non-rotating wall cloud, but I'm not sure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Q8GTw.jpg&quot; alt=&quot;Photo taken from video&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://youtu.be/MQ8W_EkR6Hc&quot; rel=&quot;nofollow noreferrer&quot;&gt;YouTube video&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Picture taken on September 9 2014... between 5-7 pm in North Georgia, about 40 miles north of Atlanta.&lt;/p&gt;&#xA;" OwnerUserId="1311" LastEditorDisplayName="user12525" LastEditDate="2019-08-27T16:23:57.977" LastActivityDate="2019-08-27T16:23:57.977" Title="What type of cloud formation are these dark low-hanging clouds?" Tags="|meteorology|clouds|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3046" PostTypeId="2" ParentId="2451" CreationDate="2014-12-14T18:10:01.330" Score="7" Body="&lt;p&gt;&lt;strong&gt;Short answer&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Na and K are incompatible in the mantle. Low degree melting that occurs deep in the mantle forms magmas enriched in Na and K. Magmas formed due to hot spots are formed deep in the mantle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Long answer&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tholeiitic basalts are voluminous magmas that form due to decompression of mantle rocks. The mantle then melts to a rather large degree at low pressures to form a relatively reduced magma (therefore tholeiite and not calc-alkaline). Their relative depletion in incompatible elements stems from the fact that the mantle peridotite being melted is a recycled rock, which lost it's incompatible elements long ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, alkali basalts are produced in smaller volumes than MORB (mid ocean ridge) tholeiitic basalts. OIB (ocean island basalts) are commonly alkaline, but alkaline rocks are not restricted to oceanic settings. They commonly occur on top of hot spots and rift zones, regardless of the nature of the lithospheric plate which they erupt though (oceanic vs continental).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I.e. Is it that the ions &lt;em&gt;(Na and K)&lt;/em&gt; are more incompatible than the Calcium ions found in the tholeiites? Why is this?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes. Sodium and potassium are less compatible than calcium in minerals that comprise mantle rocks. This figure, taken from my answer to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2950/what-are-the-high-field-strength-and-large-ion-lithophile-hfs-lil-elements-a&quot;&gt;What are the high field strength and large ion lithophile (HFS or HFSE &amp;amp; LIL or LILE) elements?&lt;/a&gt;, shows why:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/RXCuD.png&quot; alt=&quot;trace elements&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;MRFE stands for Mantle Rock Forming Elements. These elements are compatible in olivine, pyroxene, garnet, spinel and anorthite. Na and K are only monovalent and larger than the MRFE. Thus, they are compatible and in cases of mantle melting, they are partitioned to the liquid (&lt;em&gt;i.e.&lt;/em&gt; magma) phase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to understand why this enrichment in Na and K occurs, we need to understand &lt;em&gt;where&lt;/em&gt; in the mantle these magmas form. Whereas tholeiitic magmas form in shallow depths, alkaline magmas form much deeper. Experiments show that the silica undersaturated nature of these rocks requires very deep melting (tens of kilometers). Since the melting does not occur by decompression, it has to melt by heating: a hot spot. This hot spot melts mantle rocks that did not experience prior melting events by the &quot;ocean conveyor belt&quot;, and thus still retain their incompatible elements, including Na and K.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two other possible sources of Na and K enrichment in alkali rocks.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Mantle metasomatism: Na and especially K are LILs: They are highly mobile in fluids. It is possible that mantle rocks were metasomatised by K and Na bearing fluids. This would cause minerals such phlogopite (a mica) and certain varieties of amphiboles to form in the mantle. These minerals are readily melted, thus contributing Na and K to the alkali magma.&lt;/li&gt;&#xA;&lt;li&gt;Contamination by crustal rocks: This process is especially important in continental rifts. Continental crust is rich in Na and K (micas, feldspars, amphiboles) and these elements can be easily assimilated to the rising alkali magma.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;why it is that alkali basalts are more 'mature' than tholeiites?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm not exactly sure what do you mean by 'mature' but I will address the timing of alkali magmatic activity. Here is a &lt;em&gt;very&lt;/em&gt; simplified depiction of what happens:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/TBVws.png&quot; alt=&quot;volcanism and plumes&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At first (A), a young plume will still be deep. The melts that it forms are low degree and deep. Then, when the plume 'matures' (B), it causes shallow melting producing voluminous tholeiitic basalts. The margins of the plumes still produce low degrees alkali melts. When the plume wanes (or just migrates somewhere else), you get only alkali melts again (sorry, I was too lazy to draw C in the figure, but it should look not too different than A). This is similar to what's happening at the moment in Hawaii. The newest (still underwater) volcano, Loihi, erupts alkali magmas. This corresponds to stage A in the figure. This is also what the oldest rock on Hawaii (the island) are made of: alkali rocks. Most of the rocks by volume on Hawaii (again, the island) are tholeiitic basalts erupted some hundred thousands year ago, corresponding to stage B in the figure. Recent (geologically) eruptions are yet again alkaline, similar to stage C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For some extra reading about alkali rocks and related subjects, see these other questions and answers:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/2950/what-are-the-high-field-strength-and-large-ion-lithophile-hfs-lil-elements-a&quot;&gt;What are the high field strength and large ion lithophile (HFS or HFSE &amp;amp; LIL or LILE) elements?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/310/what-are-rare-earths-and-why-do-they-cluster-near-alkaline-magmatism&quot;&gt;What are rare earths and why do they cluster near alkaline magmatism?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/2293/are-there-significant-amounts-of-rare-earth-elements-on-iceland&quot;&gt;Are there significant amounts of rare earth elements on Iceland?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-12-14T18:10:01.330" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3047" PostTypeId="2" ParentId="3020" CreationDate="2014-12-14T19:13:52.930" Score="9" Body="&lt;p&gt;The largest desalination plant is the sun - with its action on the oceans and turning sea water into fresh water (by evaporation-&gt;clouds-&gt;rain) it has more capacity than any man made structure to pump ocean water. To &quot;store&quot; rain water would require the damming of a significant body of water - but you would have to tolerate a significant rise in the water level over that smaller region (Or if you can freeze the water, a very large pile of ice like Greenland).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example if you built a 150 m tall dam at Gibraltar and kept all the water from the major rivers that supply it locked up, the rise in the sea you would need is over 140 m (2.5 million square kilometers vs 3600 million square kilometers for all oceans). Unfortunately the rate of evaporation of the Mediterranean is greater then the net flux of all the rivers supplying it so that would not work unless you covered the entire thing with a reflective plastic sheet to prevent evaporation. You would kill all the flora and fauna in the sea, and all tourism, too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We need another plan to save the earth.&lt;/p&gt;&#xA;" OwnerUserId="453" LastEditorUserId="453" LastEditDate="2014-12-22T14:46:02.243" LastActivityDate="2014-12-22T14:46:02.243" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="3048" PostTypeId="2" ParentId="3038" CreationDate="2014-12-14T23:47:34.693" Score="9" Body="&lt;p&gt;This plate boundary is one of the least understood in the world, primarily due to the remoteness of the location meaning that there has not been long term observations of seismicity etc.  However, it is not a forgotten boundary and has come under recent scrutiny.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the most comprehensive studies of the area was Stanford University's &lt;a href=&quot;https://pangea.stanford.edu/research/groups/structure/projects/nerussia/projects_plate_boundary.html&quot;&gt;Plate Tectonic Evolution of Northeast Russia, 2004&lt;/a&gt; that produced the following tectonic map:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/1gVQF.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The workshop participants describe the plate boundary as transitioning from the ultraslow spreading of the Gakkel Ridge in the Arctic Ocean, across the diffuse extensional zone in the Laptev Sea in the north, into the diffuse &lt;a href=&quot;http://www.geosci.usyd.edu.au/users/prey/Teaching/Geol-3101/Wrench/IV.html&quot;&gt;transpressional&lt;/a&gt; 'Moma Rift'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They describe the uniqueness of the plate boundary as the Euler pole of rotation occurring on or near the plate boundary itself (labelled as &lt;code&gt;NA-EU Pole&lt;/code&gt; in the diagram above), which results in the general extensional in the north and compressional complexes in the south.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further research presented in the conference paper &lt;a href=&quot;http://adsabs.harvard.edu/abs/2009EGUGA..11.3548I&quot;&gt;Recent geodynamics and evolution of the Moma rift, Northeast Asia&lt;/a&gt; (Imaev et al. 2009), suggest that the &quot;Moma Rift&quot; was once an extension of the Gakkel Ridge and was a extensional rift, but as the Pole of rotation moved, it has become transpressional - with an uplift of up to about 4mm/year, representing a convergent section of the boundary.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-12-14T23:47:34.693" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3049" PostTypeId="2" ParentId="3041" CreationDate="2014-12-15T01:08:30.603" Score="13" Body="&lt;p&gt;Basically, we can ignore the heat we release compared to the effect of the &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; we release.  To be more specific:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Heat we release has only a temporary effect because heat is radiating out to space.  In fact you can get an idea of how long it takes for newly released heat to radiate away by checking how quickly temperatures drop when the sun sets.  It's fast. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The heat we released a year ago is gone.  In fact, probably the heat we released yesterday is basically gone.  There's no cumulative impact.   The extra heat we release now is effectively decaying exponentially in time as the system tries to get to its equilibrium, and its half-life is pretty short.  However, that equilibrium it is trying to reach is determined in large part by the &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; concentration.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Our release of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; is cumulative.  The &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; we released 10 years ago is still having an impact on current &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; levels, and will continue to have an impact for many, many years.  The &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; we release now is being added to this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we turn off industry, our impact due to heat released will be gone within days or weeks at most.  Our impact due to &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; released will take much longer than a human lifespan.&lt;/p&gt;&#xA;" OwnerUserId="1312" LastEditorUserId="1312" LastEditorDisplayName="user889" LastEditDate="2019-04-14T21:35:24.463" LastActivityDate="2019-04-14T21:35:24.463" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="3050" PostTypeId="2" ParentId="3036" CreationDate="2014-12-15T01:11:38.820" Score="8" Body="&lt;p&gt;Fossils are our strongest, and to most people most accessible, evidence of the great age of life on earth. The fossils in the &lt;a href=&quot;http://en.wikipedia.org/wiki/Burgess_Shale&quot;&gt;Burgess Shale&lt;/a&gt; are clearly the imprints of critters, but are a mere 505 million years old. The oldest &lt;a href=&quot;http://www.ucmp.berkeley.edu/bacteria/bacteriafr.html&quot;&gt;cyanobacteria-like fossils&lt;/a&gt; known are nearly 3.5 billion years old, among the oldest fossils currently known. There is &lt;a href=&quot;http://www.nature.com/ngeo/journal/v7/n1/full/ngeo2025.html&quot;&gt;Evidence for biogenic graphite in early Archaean Isua metasedimentary rocks&lt;/a&gt;, but requires knowledge of isotopic chemistry to understand (or dispute.) Life on earth originated before 3.5 billion years ago.&lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2014-12-15T01:11:38.820" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3051" PostTypeId="7" CreationDate="2014-12-15T03:01:59.213" Score="0" Body="&lt;ul&gt;&#xA;    &lt;li&gt;Anything not directly related to earth or planetary science&lt;/li&gt;&#xA;    &lt;li&gt;Questions that are primarily opinion-based&lt;/li&gt;&#xA;    &lt;li&gt;Questions with too many possible answers or that would require an extremely long answer&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="-1" LastEditorUserId="64" LastEditDate="2014-12-15T03:01:59.213" LastActivityDate="2014-12-15T03:01:59.213" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3052" PostTypeId="2" ParentId="3036" CreationDate="2014-12-15T08:00:33.747" Score="8" Body="&lt;p&gt;To complement @MarkRovetta answer, &lt;a href=&quot;http://meetingorganizer.copernicus.org/EGU2014/EGU2014-7421.pdf&quot;&gt;McLoughlin &amp;amp; Grosch&lt;/a&gt; reported this year during EGU findings of carbonaceous fragments that they think are biogenic in the 3.4 Ga Buck Reef Chert. Chemical tests are still ongoing however.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1578735/pdf/rstb20061834.pdf&quot;&gt;Schopf (2006)&lt;/a&gt; in his review of archean life reported a dozen of fossils in the 3 to 3.5Ga range. They are all &quot;putative&quot; fossil, however the biogenicity of the fossils he reports from the 2 to 3Ga range are frankly unquestionable. &lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2014-12-15T08:10:50.207" LastActivityDate="2014-12-15T08:10:50.207" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3053" PostTypeId="2" ParentId="3029" CreationDate="2014-12-15T09:58:57.413" Score="7" Body="&lt;p&gt;According to the &lt;a href=&quot;http://education.nationalgeographic.com/education/encyclopedia/continent/?ar_a=1&quot;&gt;National Geographic Education Encyclopedia&lt;/a&gt; webpage about continents, defines these as the main divisions of continuous land, extending out to the edge of the continental shelf - this also includes much of the surrounding islands. In the case of the division between Europe and Asia, this division is largely due to cultural differences.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The exceptions to this are what are referred to as 'microcontinents', that National Geographic site describes as being landmasses that are 'geologically distinct' from the neighbouring continents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There seems to not be a consensus on a tectonics based definition of a continent; however, given that continents change over time, it is suggested in the article &lt;a href=&quot;http://escweb.wr.usgs.gov/share/mooney/1997_Continents%20as%20lithological%20Icebergs.pdf&quot;&gt;Continents as lithological icebergs: the importance of buoyant&#xA;lithospheric roots &lt;/a&gt; (Abbott et al. 1997) as implying that the particular lithosphere is &quot;unsubductble' over two 0.25 billion year time periods - which, according to the authors, include mid-level and lower crustal levels, and that timeframe would also include Precambrian cratons as their core.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-12-15T14:52:06.650" LastActivityDate="2014-12-15T14:52:06.650" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3054" PostTypeId="1" AcceptedAnswerId="3076" CreationDate="2014-12-15T17:02:43.077" Score="9" ViewCount="355" Body="&lt;p&gt;The concept of &quot;mass extinctions&quot;, with its catastrophic connotations, is a relatively recent development in the geological sciences. It evolved in the early 1980s, driven by two landmark publications in the journal &lt;em&gt;Science&lt;/em&gt;:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://dx.doi.org/10.1126/science.208.4448.1095&quot; rel=&quot;nofollow&quot;&gt;Alvarez et al. (1980) Extraterrestrial Cause for the Cretaceous-Tertiary Extinction&lt;/a&gt;: The proposal that a asteroid or another large impactor caused the &lt;s&gt;K-T&lt;/s&gt; K-Pg mass extinction,&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://dx.doi.org/10.1126/science.215.4539.1501&quot; rel=&quot;nofollow&quot;&gt;Raup &amp;amp; Sepkoski (1982) Mass Extinctions in the Marine Fossil Record&lt;/a&gt;: Suggesting the &quot;Big Five&quot; mass extinctions.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Why did this idea develop only in the 1980s? It was known since the 19th century that extinctions had occurred. Even the stratigraphic time is divided into units constrained by different fauna found in the fossil records. What was it that made the change from a &quot;gradualist&quot; perspective of things to the &quot;catastrophic&quot; point of view?&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2016-09-13T12:47:37.380" LastActivityDate="2016-09-13T12:47:37.380" Title="Why is the concept of &quot;mass extinction&quot; a relatively recent development in geology?" Tags="|geology|earth-history|paleontology|stratigraphy|mass-extinction|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3055" PostTypeId="1" AcceptedAnswerId="3061" CreationDate="2014-12-15T17:24:22.433" Score="18" ViewCount="465" Body="&lt;p&gt;At Cape Juby, Morocco, we can see with &lt;a href=&quot;https://www.google.ca/maps/@27.9527574,-12.898903,1330m/data=!3m1!1e3&quot; rel=&quot;noreferrer&quot;&gt;Google Maps&lt;/a&gt; a rectangle of 3 km long, in which there is hundreds of little squares. What method was used to draw these squares on the sand? More importantly, why are these square drawn?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/gPT3D.jpg&quot; alt=&quot;Google Maps image of area&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="1315" LastEditorUserId="6298" LastEditDate="2022-02-06T17:31:29.020" LastActivityDate="2022-02-06T17:31:29.020" Title="Why did people draw so many continuous squares in the sand on the beach at Cape Juby?" Tags="|geology|human-influence|satellite-oddities|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="3057" PostTypeId="1" AcceptedAnswerId="3058" CreationDate="2014-12-15T20:52:35.347" Score="15" ViewCount="3811" Body="&lt;p&gt;I was checking the weather forecast just now, and it is showing that it &quot;feels like -999 °C&quot;. I never heard or saw -999 °C before. I searched other weather channels, and they were showing that it feels like 2 °C. What is the meaning of -999 °C, irrespective of the weather?&lt;/p&gt;&#xA;" OwnerUserId="1319" LastEditorUserId="725" LastEditDate="2017-03-02T08:41:26.597" LastActivityDate="2017-03-02T08:41:26.597" Title="What is the meaning of -999 degrees Celsius?" Tags="|meteorology|weather-forecasting|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="3058" PostTypeId="2" ParentId="3057" CreationDate="2014-12-15T20:55:27.480" Score="42" Body="&lt;p&gt;The value -999 is likely the &quot;fill value&quot; used in the dataset when data is missing or is not being properly filtered or handled when displayed.  In the specific case on the website you cite, it is likely a problem with the algorithm for wind chill (the &quot;feels like&quot; temperature this time of year). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It isn't a physical value and only means the value is missing. Furthermore, -999°C is not a possible value because &lt;a href=&quot;https://en.wikipedia.org/wiki/Absolute_zero&quot;&gt;absolute zero&lt;/a&gt; is –273.15°C, and it's not possible to be colder than this (at least &lt;a href=&quot;http://www.nature.com/news/quantum-gas-goes-below-absolute-zero-1.12146&quot;&gt;not in any meaningful way&lt;/a&gt;, and certainly not because of wind chill). The &lt;a href=&quot;https://en.wikipedia.org/wiki/Lowest_temperature_recorded_on_Earth&quot;&gt;coldest recorded temperature&lt;/a&gt; on earth is around –90°C. &lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="543" LastEditDate="2014-12-15T21:12:50.247" LastActivityDate="2014-12-15T21:12:50.247" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="3059" PostTypeId="2" ParentId="3055" CreationDate="2014-12-15T21:51:02.533" Score="4" Body="&lt;p&gt;It's an effort to help stymie sand dune erosion. It appears this photo was taken early before the grass or straw took root.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.dw.de/grid-of-straw-squares-turns-chinese-sand-to-soil/a-15182754&quot; rel=&quot;nofollow&quot;&gt;http://www.dw.de/grid-of-straw-squares-turns-chinese-sand-to-soil/a-15182754&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.britannica.com/EBchecked/media/120110/Worker-stabilizing-sand-dunes-near-Lingwu-northern-Hui-Autonomous-Region&quot; rel=&quot;nofollow&quot;&gt;http://www.britannica.com/EBchecked/media/120110/Worker-stabilizing-sand-dunes-near-Lingwu-northern-Hui-Autonomous-Region&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.telegraph.co.uk/news/picturegalleries/picturesoftheday/4978795/Pictures-of-the-day-12-March-2009.html?image=23&quot; rel=&quot;nofollow&quot;&gt;http://www.telegraph.co.uk/news/picturegalleries/picturesoftheday/4978795/Pictures-of-the-day-12-March-2009.html?image=23&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.permaculture.org/wp-content/uploads/2013/11/sand-dune-stabilization-by-carl-wachtmeister1.pdf&quot; rel=&quot;nofollow&quot;&gt;http://www.permaculture.org/wp-content/uploads/2013/11/sand-dune-stabilization-by-carl-wachtmeister1.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1320" LastActivityDate="2014-12-15T21:51:02.533" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="3060" PostTypeId="1" CreationDate="2014-12-15T22:15:04.737" Score="13" ViewCount="1835" Body="&lt;p&gt;Many introductory level textbooks suggest that, as a rule of thumb, the velocity of the ocean surface is around 3% the wind velocity at 10 meters above the sea surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For instance, &lt;a href=&quot;http://books.google.nl/books/about/Ocean_circulation.html?id=tbYPAQAAIAAJ&amp;amp;redir_esc=y&quot;&gt;Ocean Circulation&lt;/a&gt; by the Open University Press, page 39: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Another useful empirical observation is that the surface current speed is typically 3% of the wind speed, so that a 10 m/s wind might be expected to give rise to a surface current of about 0.3 m/s&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What are the mechanisms that result in this ratio? How universal is this relationship?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="6129" LastEditDate="2020-05-31T12:12:47.650" LastActivityDate="2020-05-31T12:12:47.650" Title="Why is ocean surface velocity around 3% of wind velocity?" Tags="|atmosphere|geophysics|oceanography|wind|ocean-currents|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3061" PostTypeId="2" ParentId="3055" CreationDate="2014-12-15T22:18:54.647" Score="15" Body="&lt;p&gt;They are not perfectly straight. Making them with modern GPS equipment should not be too difficult, you just keep a fixed distance to the previous line. They are only 5-6 meters wide.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.com/search?q=cape+juby+tarfaya+sand+beach+experiment&quot; rel=&quot;noreferrer&quot;&gt;Googling for cape juby tarfaya sand beach experiment&lt;/a&gt; I found this &lt;a href=&quot;http://www.wanderingoverland.com/?p=1397&quot; rel=&quot;noreferrer&quot;&gt;16 Jan 2013 entry&lt;/a&gt; from the blog &lt;a href=&quot;http://www.wanderingoverland.com/&quot; rel=&quot;noreferrer&quot;&gt;An overland adventure&lt;/a&gt; mentioning:&lt;br&gt;&#xA;&lt;em&gt;&quot;Between the road and the sea is another experiment to save Tarfaya from being swallowed up by the Ergs (=sand dunes), mangrove. These trees have been introduced here from the tropics as one of the few salt loving, sand rooting toughs. They seem quite young from the window of the truck so I am guessing it is too early to tell if the project has been a success.&quot;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strike&gt;Maybe this is what you are seeing. I have contacted the blog writer to ask for confirmation.&lt;/strike&gt; Update: The author confirmed that this is indeed what you're seeing: &quot;&lt;em&gt;Yes. Shame there is no picture.&lt;/em&gt;&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Subsequent &lt;a href=&quot;https://www.google.com/search?q=tarfaya+mangrove&quot; rel=&quot;noreferrer&quot;&gt;Googling for tarfaya mangrove&lt;/a&gt; turns up more info (often in French, where &lt;em&gt;palétuvier&lt;/em&gt; is indeed mangrove), e.g. this &lt;a href=&quot;https://books.google.nl/books?id=YgvV2tzf1vMC&amp;amp;pg=PT141&amp;amp;lpg=PT141&amp;amp;dq=tarfaya+mangrove&amp;amp;source=bl&amp;amp;ots=Pp_OZhckIC&amp;amp;sig=u2mB7OoUrvwC0rtOMULxakq2sNs&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ei=-lmPVM9fhP9Sl4OBMA&amp;amp;redir_esc=y#v=onepage&amp;amp;q=tarfaya%20mangrove&amp;amp;f=false&quot; rel=&quot;noreferrer&quot;&gt;Les mangoves du Sahara&lt;/a&gt; chapter from the Book &lt;em&gt;Maroc 8 - Sud du Maroc et Sahara Occidental&lt;/em&gt;. This &lt;a href=&quot;https://books.google.nl/books?id=6KHiXeJcNyMC&amp;amp;pg=PA434&amp;amp;lpg=PA434&amp;amp;dq=tarfaya+mangrove&amp;amp;source=bl&amp;amp;ots=qyQYgoTJ_Z&amp;amp;sig=5EO93J2Vbrp01OLOo4QY9Jkb5gg&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ei=-lmPVM9fhP9Sl4OBMA&amp;amp;redir_esc=y#v=onepage&amp;amp;q=tarfaya%20mangrove&amp;amp;f=false&quot; rel=&quot;noreferrer&quot;&gt;Lonely Planet E-Book PDF Marokko Reiseführer&lt;/a&gt; which is almost a literal translation, mentions a 900 meter long strip, but the artifact in the picture is approx 3.2 km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The planting project was named &lt;a href=&quot;http://themanzanarproject.com/PNAS.html&quot; rel=&quot;noreferrer&quot;&gt;The Manzanar project&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="595" LastEditorUserId="595" LastEditDate="2015-03-28T10:37:16.403" LastActivityDate="2015-03-28T10:37:16.403" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3062" PostTypeId="2" ParentId="2966" CreationDate="2014-12-16T09:16:14.427" Score="22" Body="&lt;p&gt;Due to the obliquity of the Earth, no place would truly have a single season, which in this answer is taken as having consistent conditions, particularly in terms of temperature and precipitation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An environment that would qualify as having minimal seasonality are in the equatorial tropics, which according to the article &lt;a href=&quot;http://www-public.jcu.edu.au/learningskills/idc/groups/public/documents/journal_article/jcudev_017177~4.pdf&quot; rel=&quot;noreferrer&quot;&gt;Climatic seasonality, resource bottlenecks,&#xA;and abundance of rainforest birds:&#xA;implications for global climate change&lt;/a&gt; (Williams and Middleton, 2008) due to the almost consistent insolation, as shown below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/nnlO4.gif&quot; alt=&quot;enter image description here&quot;&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.physicalgeography.net/fundamentals/6i.html&quot; rel=&quot;noreferrer&quot;&gt;Image source&lt;/a&gt; - the blue line represents the yearly trends across the year for  equatorial regions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although, according to the article, the temperature remains fairly constant, precipitation can have alternating wet and dry periods, and can affected by other climatic factors (depending on location) such as El Niño, monsoons etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, according to the &lt;a href=&quot;http://www.meteorologyclimate.com/koppenclassification.htm&quot; rel=&quot;noreferrer&quot;&gt;Köppen climate classification&lt;/a&gt; system, the closest environment that would have minimal seasonality is classified as &lt;code&gt;Af&lt;/code&gt;, which are warm moist rainforest, located in the areas shown below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/61U9I.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Tropical_rainforest_climate&quot; rel=&quot;noreferrer&quot;&gt;Image source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An example of a location in such an environment is the city of Andagoya, Colombia, South America, (latitude 5N, elevation 65m) which has the following annual temperature and precipitation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/06Or1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image source: &lt;a href=&quot;http://www.physicalgeography.net/fundamentals/7v.html&quot; rel=&quot;noreferrer&quot;&gt;Climate Classification and Climatic Regions of the World&lt;/a&gt;, which describes the classification &lt;code&gt;Af&lt;/code&gt; as lying within the influence of the &lt;a href=&quot;http://www.physicalgeography.net/physgeoglos/i.html#intertropical_convergence_zone&quot; rel=&quot;noreferrer&quot;&gt;Intertropical Convergence Zone (ITCZ)&lt;/a&gt; and experiencing very little variation in temperature and precipitation throughout the year.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="111" LastEditDate="2014-12-21T21:54:34.017" LastActivityDate="2014-12-21T21:54:34.017" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3063" PostTypeId="1" AcceptedAnswerId="3066" CreationDate="2014-12-16T10:25:05.067" Score="23" ViewCount="34231" Body="&lt;p&gt;Is the color of the sky at noon (local time) in, say, NY, Buenos Aires, London, Nairobi, Sydney, New Delhi and Tokyo the same? I choose the specific time of noon to exclude the twilight colors of the sky and I choose cities that aren't above the northern or southern pole to make it easier.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also can the color of the sky be the same or not depending of the season? For instance, the color of the sky of Buenos Aires on January 1st would be the color of the sky in NY on June 1st.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, is the color of the sky of one region on earth the same all year round and all day long, once again, without taking in account twilight?&lt;/p&gt;&#xA;" OwnerUserId="1315" LastEditorUserId="725" LastEditDate="2016-09-17T00:56:12.020" LastActivityDate="2019-01-21T09:01:42.450" Title="Is the color of the sky the same everywhere on earth?" Tags="|atmosphere|radiative-transfer|" AnswerCount="5" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="3065" PostTypeId="1" AcceptedAnswerId="3070" CreationDate="2014-12-16T15:04:05.983" Score="3" ViewCount="771" Body="&lt;p&gt;The Vostok station can observe temperatures as low -90 C during winter.  Human skin gets frozen wounds on the spot on direct contact with such cold air and precautions must be made to avoid open exposed skin during outdoor operations at these temperatures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't thing going outside is possible, but also I think that they must have some solution in case going outside can't be avoided. Especially because the possible problems of heating and similar infrastructure are in their case life-threating consequences.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What do they wear? I think something similar to a space suit, but instead of compression it contains heated internal atmosphere, should work. Do they have something like this?&lt;/p&gt;&#xA;" OwnerDisplayName="user432" LastEditorUserId="64" LastEditDate="2014-12-17T03:48:20.070" LastActivityDate="2014-12-17T03:48:20.070" Title="What do the researchers in Antarctica wear if they must go outside during winter?" Tags="|temperature|" AnswerCount="1" CommentCount="0" ClosedDate="2014-12-16T21:53:18.767" ContentLicense="CC BY-SA 3.0" />
  <row Id="3066" PostTypeId="2" ParentId="3063" CreationDate="2014-12-16T15:48:15.520" Score="15" Body="&lt;p&gt;The blue color of the sky is due to Rayleigh scattering.  As light from the sun shines down it scatters off of (mostly) nitrogen molecules in the atmosphere.  Without this process, the sky would be dark during the day except for the bright sun, moon, and stars.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rayleigh scattering is more efficient for shorter wavelengths.  So, even though the Sun provides a full spectrum, blue is scattered more efficiently than the longer wavelengths of light.  Thus blue is the dominant color you see.  See &lt;a href=&quot;http://en.wikipedia.org/wiki/Rayleigh_scattering&quot; rel=&quot;noreferrer&quot;&gt;Rayleigh scattering (Wikipedia)&lt;/a&gt; for more info on Rayleigh Scattering. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, to answer your question, the color of the sky is the same for most places on the Earth at noon because the sunlight is relatively constant and the atmosphere is relatively uniform in composition (nitrogen and oxygen).  The exceptions are air pollution, high latitudes, and high altitudes.  Air pollution and high latitudes have similar effects in that more attenuation of the light occurs as it travels through more atmosphere, and therefore colors change like you see at twilight.  Air pollution in particular is a highly variable source of scattering and absorption that gets quite extreme when there are  high concentrations of particles.   High latitudes change the geometry, similar to twilight.  In contrast, high altitudes have less atmosphere, so if you go high enough (e.g. in a hot-air balloon) there just won't be much scattered light and it will get dark due to the lack of atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the wikipedia article:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In addition the oxygen in the Earth's atmosphere absorbs wavelengths at the edge of the ultra-violet region of the spectrum. The resulting color, which appears like a pale blue, actually is a mixture of all the scattered colors, mainly blue and green. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The reddening of sunlight is intensified when the sun is near the horizon, because the volume of air through which sunlight must pass is significantly greater than when the sun is high in the sky. The Rayleigh scattering effect is thus increased, removing virtually all blue light from the direct path to the observer. The remaining unscattered light is mostly of a longer wavelength, and therefore appears to be orange.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="6093" LastEditDate="2016-10-04T13:25:20.210" LastActivityDate="2016-10-04T13:25:20.210" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="3067" PostTypeId="2" ParentId="3063" CreationDate="2014-12-16T15:57:49.610" Score="14" Body="&lt;p&gt;To supplement farrenthorpe's answer, the color of the sky will be a function of the path length between the top of atmosphere and your eye along the path from the sun to you.  Due to Rayleigh scattering, shorter wavelengths will scatter before longer ones.  As the path length increases more of the longer wavelengths will be scattered.  The color of the sky is the sum of all of the photons scattered out of the beam of photons from the sun and then re-scattered so they end up hitting your eye.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Our blue sky is a result of the depth of the atmosphere (small).  If the atmosphere was less deep (shorter path length) the sky would tend toward darker blue/violet.  If the atmosphere was deeper (longer path length) the sky would tend toward oranges, pinks and reds.  We see the latter case during sunset.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given observations taken at solar noon at latitudes between the 66 N/S there likely is some variance in sky color as there will be subtle path length differences at different latitudes, particularly between the hemispheres due to the earths tilt.  However, you would likely need a sensitive instrument to notice these differences and could consider it a constant.  The variance in sky color during the diurnal cycle from dawn till dusk is a far stronger effect than looking only at solar noon day-to-day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that I am only considering scattering by a uniform atmosphere neglecting the effects of aerosols and water vapor.  Foris's answer takes up this topic (and you can easily observe the difference in how the sky looks on a very dry day vs a very humid day).&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2014-12-16T16:43:49.180" LastActivityDate="2014-12-16T16:43:49.180" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3068" PostTypeId="2" ParentId="3063" CreationDate="2014-12-16T16:31:17.687" Score="28" Body="&lt;p&gt;Absolutely not. While the answers by casey and farrenthorpe correctly state that the blue color is due to Rayleigh scattering, the composition of the atmosphere varies considerably from place to place - and with different composition come different degrees of scattering, and different color / intensity. Typically regions of greater industrial activity will carry larger densities of particles which, in the presence of moisture in the air, will become scatterers. The wavelength dependence is a function of the size of the particles - so as the size changes, so will the color.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See my answer to the question &lt;a href=&quot;https://physics.stackexchange.com/q/129492/26969&quot;&gt;Why is the sun brighter in Australia compared to parts of Asia&lt;/a&gt;. The same mechanism that makes the sun &quot;brighter&quot; also makes the sky &quot;darker&quot; (namely, less scatter).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is true even on a nominally &quot;clear&quot; day - because there is always some particulate matter in the atmosphere. And the concentration of particulates really does vary with location on earth - see this image  as an example (from &lt;a href=&quot;http://www.nasa.gov/images/content/483910main1_Global-PM2.5-map-670.jpg&quot; rel=&quot;noreferrer&quot;&gt;NASA&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/9NSGA.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other point worth keeping in mind is altitude: the sky looks darker when you are at the top of a mountain, even if the composition of the atmosphere is the same. That is because there is &quot;less atmosphere&quot; to scatter. And of course, some places on Earth are (always) at a different altitude...&lt;/p&gt;&#xA;" OwnerUserId="453" LastEditorUserId="453" LastEditDate="2017-07-07T13:26:13.263" LastActivityDate="2017-07-07T13:26:13.263" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="3069" PostTypeId="2" ParentId="2970" CreationDate="2014-12-16T16:44:34.727" Score="3" Body="&lt;p&gt;Remember the recent disappearance of the Malaysian Airlines flight 370, assumed lost off the coast of Australia? They could not really begin looking for it without first getting a decent map of the ocean floor. It was &quot;uncharted&quot; for the purpose of that search - for most people, &quot;really deep&quot; is all you need to know for practical purposes, but in this case the information about the seabed that was needed was not available.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;http://www.jacc.gov.au/families/operational_reports/opsearch-update-20141210.aspx&quot; rel=&quot;nofollow&quot;&gt;MH370 Operational Search Update—10 December 2014&lt;/a&gt; for updates on the search (and the &quot;charting&quot; operation that is ongoing in that region).&lt;/p&gt;&#xA;" OwnerUserId="453" LastEditorUserId="6093" LastEditDate="2016-09-23T13:16:28.827" LastActivityDate="2016-09-23T13:16:28.827" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3070" PostTypeId="2" ParentId="3065" CreationDate="2014-12-16T21:25:57.743" Score="4" Body="&lt;p&gt;The US Antarctica Program publishes information about the required extreme cold weather gear. It's provided by the government and has to be returned after your deployment ends. The list is &lt;a href=&quot;http://www.usap.gov/USAPgov/travelAndDeployment/contentHandler.cfm?id=1860#gearsizes&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt; along with other information. Here's another document that discuses &lt;a href=&quot;http://www.usap.gov/travelAndDeployment/documents/FieldManual-Chapt1ExtremeColdWeatherClothing.pdf&quot; rel=&quot;nofollow&quot;&gt;clothing&lt;/a&gt;. I've extracted the list below. &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Jackets &#xA;1 each GOR-TEX® wind jacket &#xA;1 each Helly Hansen® rain jacket &#xA;1 each polar fleece jacket &#xA;1 each Carhartt® jacket optional &#xA;1 each Carhartt vest optional &#xA;1 each red down parka optional &#xA;&#xA;Pants &#xA;1 each GOR-TEX bib coveralls for grantees only &#xA;1 each Helly Hansen rain pants &#xA;1 each polar fleece pants &#xA;1 each Carhartt bib coveralls optional &#xA;1 each Carhartt pants &#xA;&#xA;Thermal &#xA;2 each thermal top &#xA;2 each thermal bottoms &#xA;&#xA;Hat and Neck &#xA;1 each Balaklava &#xA;1 each neck gaiter &#xA;1 each polar fleece cap &#xA;&#xA;Gloves &#xA;1 pair leather work gloves (unlined) &#xA;1 pair leather work gloves (insulated) &#xA;1 pair rubber gloves (with liners) &#xA;1 pair GOR-TEX mitts &#xA;1 pair polypropylene gloves &#xA;1 pair wool gloves &#xA;&#xA;Footwear &#xA;2 pair tube socks &#xA;1 pair snow boots (Sorel™ or LaCrosse®) &#xA;1 each fisherman boots (rubber or steel-toed) optional &#xA;&#xA;Miscellaneous &#xA;1 pair goggles &#xA;1 each duffle bag &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="1339" LastActivityDate="2014-12-16T21:25:57.743" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3071" PostTypeId="1" AcceptedAnswerId="3073" CreationDate="2014-12-16T22:48:43.433" Score="20" ViewCount="1377" Body="&lt;p&gt;There are many pictures I've seen of lightning coming out of the plume of smoke caused by a volcano (Often called 'Volcano Lightning').&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/u3obN.jpg&quot; alt=&quot;Volcano Lightning&quot;&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why does this happen?&lt;/p&gt;&#xA;" OwnerUserId="115" LastEditorDisplayName="user889" LastEditDate="2015-03-26T08:48:10.253" LastActivityDate="2020-08-02T07:23:41.480" Title="Why does Volcano Lightning occur?" Tags="|volcanology|volcanoes|lightning|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="3072" PostTypeId="2" ParentId="3071" CreationDate="2014-12-16T23:02:23.943" Score="6" Body="&lt;p&gt;From my knowledge, lightning is formed when a static charge develops between ice particles in a cloud, and the charge is neutralized via an electric strike to the ground.&lt;br&gt;&#xA;In a volcanic cloud, there is a lot of ash and very high temperatures. The ash is a substitute for the ice particles.  The temperature difference between the ground and air allow for easier charge build-up as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Volcanic clouds also cause large updrafts which may result in a storm and &quot;normal&quot; lightning.&lt;/p&gt;&#xA;" OwnerUserId="1282" LastActivityDate="2014-12-16T23:02:23.943" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3073" PostTypeId="2" ParentId="3071" CreationDate="2014-12-17T00:56:35.110" Score="17" Body="&lt;p&gt;To actively take measurements from the mount of an erupting volcano is not practical, so the mechanisms are often modeled in a laboratory, such as what was performed in the article &lt;a href=&quot;http://geology.gsapubs.org/content/42/1/79.full&quot; rel=&quot;noreferrer&quot;&gt;Experimental generation of volcanic lightning&lt;/a&gt; (Cimarelli et al. 2014), who determined that volcanic lightning is controlled by the dynamics of the volcanic jet and how much fine particulate matter is present.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A key observation that the researchers found was that the movement of &lt;em&gt;clusters&lt;/em&gt; of charged volcanic ash and other particles form to generate an electric potential, critical for the generation of lightning. An idealised diagram of this process is shown below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/F4V9f.jpg&quot; alt=&quot;Charge separation forms in ash cloud&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.groundtruthtrekking.org/blog/?p=850&quot; rel=&quot;noreferrer&quot;&gt;Image source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to why the particles themselves are charged was researched in the article &lt;a href=&quot;http://www.electrostatics.org/images/ESA_2014_G_Aplin_et_al.pdf&quot; rel=&quot;noreferrer&quot;&gt;Electrical charging of volcanic ash&lt;/a&gt; (Aplin et al. 2014), which suggests the ash becomes charged through &lt;a href=&quot;http://en.wikipedia.org/wiki/Mechanically_stimulated_gas_emission&quot; rel=&quot;noreferrer&quot;&gt;fractoemission&lt;/a&gt;, &lt;a href=&quot;http://en.wikipedia.org/wiki/Triboelectric_effect&quot; rel=&quot;noreferrer&quot;&gt;triboelectrification&lt;/a&gt;, and the &lt;a href=&quot;http://en.wikipedia.org/wiki/Dirty_thunderstorm&quot; rel=&quot;noreferrer&quot;&gt;“dirty thunderstorm” mechanism&lt;/a&gt;, and the authors also suggest that natural radioactivity in the volcanic emissions may play a role.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="1348" LastEditDate="2014-12-17T16:17:58.753" LastActivityDate="2014-12-17T16:17:58.753" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3075" PostTypeId="2" ParentId="3071" CreationDate="2014-12-17T05:23:51.123" Score="5" Body="&lt;p&gt;The discharges are due to the charged particles carried aloft by the plumes rising from or shot from a volcano. The plumes may be dominated by positive charge but usually it also contains regions of negative charge. These regions can discharge to one another or to ground. The current in a discharge can heat the air so intensely that the air expands faster than the speed of the sound &amp;mdash; such expansion sends out a shock wave which reaches an observer (who is hopefully at a safe distance) as a loud boom!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Several effects might account for the charged particles being in the plumes:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;If water suddenly encounters molten lava, it can bead up in what is called the Leidenfrost effect, floating on vapour layer. Any such large drop quickly splits into charged smaller drops, which are then carried into the atmosphere by the rising plume of hot air and water vapour.&lt;/li&gt;&#xA;&lt;li&gt;Magma becomes charged when it fractures as it either hits water or crashes through the upper end of volcano conduit and then is ejected in the plume. Once the charged particles are aloft, collisions can transfer charge from one particle to another or even cause additional charging as occurs in Wind - blown dust.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="1344" LastEditorUserId="-1" LastEditDate="2014-12-17T13:30:47.660" LastActivityDate="2014-12-17T13:30:47.660" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3076" PostTypeId="2" ParentId="3054" CreationDate="2014-12-17T08:08:42.340" Score="15" Body="&lt;p&gt;The idea of mass extinction is not that recent actually: &lt;strong&gt;Cuvier (1798)&lt;/strong&gt;, &lt;strong&gt;Buckland (1823)&lt;/strong&gt; and &lt;strong&gt;d'Orbigny (1851)&lt;/strong&gt; for instance were already talking about global catastrophes in earth history, linked to extinctions. But during the same period, &lt;strong&gt;Brocchi (1814)&lt;/strong&gt; and &lt;strong&gt;Lyell (1832)&lt;/strong&gt; proposed that extinctions of species occurred individually and were a gradual process (either only linked to an intrinsic taxa longevity for Brocchi, or variations in the environment for Lyell). Darwin, following Lyell, also thought that extinctions were gradual and not catastrophic. He also noted the fact that hiatuses in the fossil record or artificial concentration in some strata could show apparent extinction event.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The issue with mass extinction is that to demonstrate their existence you need to be able to demonstrate extinction synchronicity and quantify the amount of species going extinct (to show that it is more than just background noise).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Demonstrating the synchronicity of one mass extinction is what &lt;strong&gt;Alvarez et al. 1980&lt;/strong&gt; managed to do thanks to the Iridium layer at the K/Pg boundary. More generally, the possibility of correlating extinctions precisely is something that evolved in par with the evolution of stratigraphic tools, and the 1970-1980s is the period during which high-resolution stratigraphic methods arose (chronostratigraphy, magnetostratigraphy, stable isotope stratigraphy for instance).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quantifying mass extinction is what Jack Sepkoski did with his compendium of marine invertebrates (see &lt;strong&gt;Sepkoski 1978, 1979; Raup &amp;amp; Sepkoski 1982&lt;/strong&gt;, etc.). Today, the PbDb (PaleoBiology DataBase) is the project which focusses on that specific issue (see for instance &lt;strong&gt;Alroy et al. 2001&lt;/strong&gt;). It still remains today the main hurdle in studying mass extinctions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Alroy, J. &lt;em&gt;et al.&lt;/em&gt;, 2001. &lt;a href=&quot;http://www.pnas.org/cgi/doi/10.1073/pnas.111144698&quot;&gt;Effects of sampling standardization on estimates of Phanerozoic marine diversification.&lt;/a&gt; PNAS, 98(11): 6261-6266.&lt;br&gt;&#xA;Alvarez, L. W. &lt;em&gt;et al.&lt;/em&gt;, 1980. &lt;a href=&quot;http://www.sciencemag.org/content/208/4448/1095.short&quot;&gt;Extraterrestrial Cause for the Cretaceous-Tertiary Extinction&lt;/a&gt;. Science, 208: 1095-1108.&lt;br&gt;&#xA;Brocchi, 1814. Conchiologia fossile subapennina, con osservazioni geologische sugli Apennini e sul suolo adiacente. Stamperia reale. &lt;em&gt;(&lt;a href=&quot;https://archive.org/details/conchiologiafos00brocgoog&quot;&gt;link to 1843 reedition&lt;/a&gt;)&lt;/em&gt;&lt;br&gt;&#xA;Buckland, 1823. &lt;a href=&quot;http://books.google.de/books/about/Reliquiae_Diluvianae.html?id=OYc_AAAAcAAJ&amp;amp;redir_esc=y&quot;&gt;Reliquiae Diluvianae or, Observations on the Organic Remains attesting the Action of a Universal Deluge&lt;/a&gt;. Murray, London.&lt;br&gt;&#xA;Cuvier, G., 1798. &lt;a href=&quot;http://gallica.bnf.fr/ark:/12148/bpt6k3217h.image&quot;&gt;Mémoire sur les espèces d'éléphans vivants et fossiles&lt;/a&gt;. Mémoires de l'institut national des sciences et des lettres, 2: 1-32.&lt;br&gt;&#xA;d'Orbigny, A. 1851. &lt;a href=&quot;http://gallica.bnf.fr/ark:/12148/bpt6k6260677z&quot;&gt;Cours élémentaires de paléontologie et de géologie stratigraphique&lt;/a&gt;. Masson, Paris.&lt;br&gt;&#xA;Lyell, C. 1832. &lt;a href=&quot;http://www.gutenberg.org/ebooks/33224&quot;&gt;Principles of Geology&lt;/a&gt;. Murray, London.&lt;br&gt;&#xA;Raup D. M. &amp;amp; Sepkoski J. J. Jr, 1982. &lt;a href=&quot;http://dx.doi.org/10.1126/science.215.4539.1501&quot;&gt;Mass Extinctions in the Marine Fossil Record&lt;/a&gt;. Science, 215: 1501-1503.&lt;br&gt;&#xA;Sepkoski J. J. Jr, 1978. &lt;a href=&quot;http://www.jstor.org/stable/2400203&quot;&gt;A kinetic model of Phanerozoic taxonomic diversity I. Analysis of marine orders.&lt;/a&gt; Paleobiology, 4: 223-251.&lt;br&gt;&#xA;Sepkoski J. J. Jr, 1979. &lt;a href=&quot;http://www.jstor.org/stable/2400257&quot;&gt;A kinetic model of Phanerozoic taxonomic diversity II. Early Phanerozoic families and multiple equilibria.&lt;/a&gt; Paleobiology, 5: 223-251. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2015-04-24T07:19:11.833" LastActivityDate="2015-04-24T07:19:11.833" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3077" PostTypeId="1" AcceptedAnswerId="3078" CreationDate="2014-12-17T10:09:22.917" Score="12" ViewCount="848" Body="&lt;p&gt;A large area of The Netherlands is below sea level. There are two non-anthropogenic reasons that I can think of:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Compaction of delta sediments that lie below the country,&lt;/li&gt;&#xA;&lt;li&gt;A side effect of the isostatic rebound after the deglaciation of Scandinavia.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Are there any other reasons? What are the relative proportions in magnitude of these factors?&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2014-12-17T14:10:20.477" LastActivityDate="2014-12-18T11:12:59.007" Title="What are the non-anthropogenic causes of The Netherlands' low elevation?" Tags="|geophysics|sedimentology|glaciology|topography|isostasy|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="3078" PostTypeId="2" ParentId="3077" CreationDate="2014-12-17T14:15:02.517" Score="17" Body="&lt;p&gt;&lt;strong&gt;Forming of coastline&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During the last ice age, the North Sea was dry. When the ice melted sea levels slowly started to rise again and due to tides and currents&#xA;a barrier of dunes was formed along what approximately is today's coast line. This created an area of land that fell dry during ebb-tide and flooded during high tide (this can still be seen in the '&lt;a href=&quot;http://en.wikipedia.org/wiki/Wadden_Sea&quot;&gt;Waddenzee&lt;/a&gt;' in the North of the Netherlands where you can walk to some of the islands during low tide). The big rivers that flow through the Netherlands brought in more sand, slowly keeping larger parts of the land dry. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Isostatic rebound&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During the ice age, the surface of Scandinavia was pushed down. After the ice melted it started to rise again and pushed the Western and Northern part of Netherlands down. Strangely enough the Southern and Eastern parts of the Netherlands are rising, so it seems the Netherlands is tilting.&#xA;I'm not sure how large the isostatic effect has been, but we know that the North of the Netherlands is still &lt;a href=&quot;http://www.kennislink.nl/publicaties/nederland-zeespiegel-bodemdaling-en-watermanagement&quot;&gt;going down with about 2cm per century (source in Dutch)&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Human influence&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know you've asked for non-anthropogenic causes, but I'm going to include this anyway because it seems human influence has had a much bigger effect on elevation than the isostatic rebound. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the 11th century the Dutch started to actively shape the land by building dikes and later also by using wind mills to pump out water. The &lt;a href=&quot;http://en.wikipedia.org/wiki/Flevopolder&quot;&gt;Flevopolder&lt;/a&gt; is an example of a large part of land that has been created by the Dutch in the 1950s and 60s. When groundwater levels became lower the moors settled and started oxidizing. Researchers think that &lt;a href=&quot;http://www.uu.nl/NL/Actueel/Pages/Randstadzaktdoorinklinkenveenlagen.aspx&quot;&gt;the settling and oxidation of moors today is responsible for up to 15mm decline per year (source in Dutch)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally in the 16th and 17th century a lot of peat was removed from the moors and used as fuel. Peat removal created new lakes, but some of those lakes were pumped dry later and were used as farmland. Also, the weight of dikes and houses on moors still cause subsidence today in areas in the West.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the Northeastern part of the Netherlands gas extraction has also caused &lt;a href=&quot;http://wetenschap.infonu.nl/natuurverschijnselen/16761-oorzaken-van-zeespiegelstijging.html&quot;&gt;local elevation drops of up to 30cm (source in Dutch)&lt;/a&gt; in the last 40 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Other sources (all in Dutch):&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.geologievannederland.nl/landschap/landschapsvormen/strandwal&quot;&gt;http://www.geologievannederland.nl/landschap/landschapsvormen/strandwal&lt;/a&gt; (forming of shoreline)&#xA;&lt;a href=&quot;http://nl.wikipedia.org/wiki/Veenpolder_(poldertype)&quot;&gt;http://nl.wikipedia.org/wiki/Veenpolder_(poldertype)&lt;/a&gt; (Dutch moors)&lt;/p&gt;&#xA;" OwnerUserId="1109" LastEditorUserId="1109" LastEditDate="2014-12-17T14:22:31.307" LastActivityDate="2014-12-17T14:22:31.307" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3079" PostTypeId="1" CreationDate="2014-12-17T15:21:46.287" Score="8" ViewCount="323" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/O0m3k.png&quot; alt=&quot;http://i.imgur.com/ZXSI69B.png&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/j41Qf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;This sounding&lt;/a&gt; is from 2 hours after the 2.6 mile wide &lt;a href=&quot;http://www.srh.noaa.gov/oun/?n=events-20130531-elreno&quot; rel=&quot;nofollow noreferrer&quot;&gt;El Reno tornado on May 31 2013&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="1311" LastEditorUserId="64" LastEditDate="2014-12-18T02:39:27.117" LastActivityDate="2015-10-31T14:58:38.007" Title="What's with this anomaly in this sounding (the CAPE and CIN readings)?" Tags="|meteorology|radiosounding|mesoscale-meteorology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="3080" PostTypeId="2" ParentId="2680" CreationDate="2014-12-17T15:55:35.370" Score="4" Body="&lt;p&gt;The radius of the Fresnel zone formula gives resolution as a function of the dominant frequency in the spectrum. And indeed, the higher the dominant frequency, the higher the resolution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to what Way of the Geophysicist explained, I'd add specifically on Yilmaz that waht he is talking about is the importance of bandwidth. The plot you attached shows that with progressively increasing bandwidth, you are able to resolve better and better the reflectors in the reflectivity model (top panel) and eventually, with a bandwidth upwards of 10-50 Hz, even the reflectors separated by only 12 ms (third from the left in each panel). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To understand this I find it helpful to also look at Figure 1.1.29 [note &lt;a href=&quot;https://books.google.ca/books?id=ceu1x3JqYGUC&amp;amp;printsec=frontcover&amp;amp;dq=yilmaz%20seismic%20data%20analysis&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ei=8faRVL7wPMm1ogTr_IKACA&amp;amp;ved=0CDEQuwUwAA#v=onepage&amp;amp;q=yilmaz%20seismic%20data%20analysis&amp;amp;f=false&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt; ], which shows a series of band-limited responses of the same reflectivity model as in Figure 1.1.30. Figure 1.1.29 demonstrates that if you increase the dominant frequency (the center of the narrow band range) only, you do not get improved resolution; you need also to increase the bandwidth as in Figure 1.1.30.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Figure 1.1.23 will also help understanding: it shows a series of zero-phase wavelets in which, with progressively increasing bandwidth, the wavelets are more compressed in time (hence higher temporal resolution). Notice that the amplitude (size) of the side lobes is decreasing as well with increasing bandwidth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://books.google.ca/books?id=ceu1x3JqYGUC&amp;amp;printsec=frontcover&amp;amp;dq=yilmaz%20seismic%20data%20analysis&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ei=8faRVL7wPMm1ogTr_IKACA&amp;amp;ved=0CDEQuwUwAA#v=onepage&amp;amp;q=yilmaz%20seismic%20data%20analysis&amp;amp;f=false&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt; There's a google book preview and the three figures I refer to are included. Scroll to the book TOC &lt;a href=&quot;https://books.google.ca/books?id=ceu1x3JqYGUC&amp;amp;printsec=frontcover&amp;amp;dq=yilmaz%20seismic%20data%20analysis&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ei=8faRVL7wPMm1ogTr_IKACA&amp;amp;ved=0CDEQuwUwAA#v=onepage&amp;amp;q=yilmaz%20seismic%20data%20analysis&amp;amp;f=false&quot; rel=&quot;nofollow&quot;&gt;from here&lt;/a&gt; and click on link to Ch1.&lt;/p&gt;&#xA;" OwnerUserId="144" LastEditorUserId="144" LastEditDate="2014-12-17T21:47:08.750" LastActivityDate="2014-12-17T21:47:08.750" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="3081" PostTypeId="2" ParentId="3079" CreationDate="2014-12-18T02:39:06.270" Score="7" Body="&lt;p&gt;Your screenshot lists the raob as station 72357 on 2013-06-01 00Z.  Station 72357 is OUN and the sounding for that day time is available at the &lt;a href=&quot;http://www.spc.noaa.gov/exper/soundings/archive/13060100_OBS/&quot; rel=&quot;noreferrer&quot;&gt;SPC sounding archive&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/TWRb9.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The SPC sounding analysis shows 3351 J kg$^{-1}$ CAPE and -76 J kg$^{-1}$ CIN for surface parcels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My speculation for your anomolous non-physical values of CAPE and CIN is that the algorithm used in that software perhaps doesn't handle the lack of stratopheric data well.  The calculation of CAPE is the parcel buoyancy integrated from the level of free convection (LFC) to the equilibrium level (EL).  This sounding has no EL because the temperature data stops before the tropopause and never increases to equal the temperature of the lifted parcel.  A naive algorithm that does not take this into account would have issues calculating the CAPE and potentially produce undefined output.  I think that is the case in the software in your screenshot.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2014-12-18T05:12:31.423" LastActivityDate="2014-12-18T05:12:31.423" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3082" PostTypeId="1" AcceptedAnswerId="4398" CreationDate="2014-12-18T04:21:29.133" Score="10" ViewCount="143" Body="&lt;p&gt;Given that the age of the oldest zircon samples are about 4.4 billion years old, and meteorites and other extraterrestrial samples can also give us some indication about the Earth's composition into the Hadean era (source: &lt;a href=&quot;http://www.amnh.org/education/resources/rfl/web/essaybooks/earth/cs_zircon_chronolgy.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zircon Chronology: Dating the Oldest Material on Earth&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many resources refer to the earliest atmosphere as being (for example):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;As a result of the high temperatures at the center of the Earth, and due to volcanic activity, the crust emitted halogen gasses, ammonia, hydrogen, carbon dioxide, methane, water vapor, and other gasses. In the following 100 million years, these gasses accumulated to form the primordial atmosphere.  This atmosphere was quite similar to the atmosphere of Titan, one of the larger moons of Saturn.  The primordial atmosphere is believed to have reached a pressure of 250 atmospheres and would have been extremely toxic to life as we now know it&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://palaeos.com/hadean/hadean.htm#Atmosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Hadean Eon&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many mechanisms are suggested in this and many other resources, from impacts to volcanic outgassing etc. &lt;strong&gt;But what does measured geochemical data tell us about the Earth's earliest palaeoclimatic conditions?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This question is related to the previous questions:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/2914/what-if-any-paleoclimate-data-can-be-derived-from-igneous-rocks&quot;&gt;What, if any, paleoclimate data can be derived from igneous rocks?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/167/what-if-any-paleoclimate-data-can-be-derived-from-stromatolite-fossils&quot;&gt;What, if any, paleoclimate data can be derived from stromatolite fossils?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;But, this question is looking at the earliest palaeoclimatic conditions of the Earth.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-02-11T09:50:24.073" Title="What does geochemical data tell us about Earth's earliest palaeoclimatic conditions?" Tags="|geochemistry|earth-history|paleoclimatology|" AnswerCount="1" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3083" PostTypeId="1" AcceptedAnswerId="3084" CreationDate="2014-12-18T05:52:40.710" Score="7" ViewCount="607" Body="&lt;p&gt;What is the difference between &quot;liquid water content&quot; and &quot;absolute humidity&quot; in meteorology? Both have units of mass/volume.&lt;/p&gt;&#xA;" OwnerUserId="1167" LastActivityDate="2014-12-18T06:26:46.890" Title="LWC and Absolute Humidity" Tags="|meteorology|humidity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3084" PostTypeId="2" ParentId="3083" CreationDate="2014-12-18T06:26:46.890" Score="8" Body="&lt;p&gt;According to the online chapter &lt;a href=&quot;http://www.eos.ubc.ca/books/Practical_Meteorology/Chapters/Ch04-Moist.pdf&quot;&gt;Water Vapor&lt;/a&gt; (University of British Columbia), the two variables you ask about are defined as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Absolute humidity&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\rho_{v}=\frac{m_{water\ vapour}}{volume}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Liquid water content&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\rho_{LWC}=\frac{m_{liquid\ water}}{volume}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main difference is that absolute humidity measures the mass of water &lt;em&gt;vapour&lt;/em&gt; and the LWC measures the mass of suspended or falling &lt;em&gt;liquid&lt;/em&gt; water content in a unit volume of air. A handy definition linking the two terms is (from the linked document):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;LWC is the liquid-water analogy to the absolute&#xA;  humidity for water vapor.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-12-18T06:26:46.890" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3086" PostTypeId="1" CreationDate="2014-12-18T20:03:14.547" Score="16" ViewCount="2512" Body="&lt;p&gt;The currently accepted theory for P-T mass extinction is environmental change triggered by the Siberian Traps volcanic activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A paper&lt;sup&gt;&lt;a href=&quot;http://dx.doi.org/10.1029/2008GC002149&quot; rel=&quot;noreferrer&quot;&gt;(1)&lt;/a&gt;&lt;/sup&gt; suggests that the Siberian Traps were caused by a hotspot created after an impact event on what was back then the antipode of Siberia: the Wilkes Land crater.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Thus, the impact may have triggered the “Great Dying” at the end of the Permian and contributed to the development of the hot spot that produced the Siberian Traps and now may underlie Iceland.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, another more recent review paper&lt;sup&gt;&lt;a href=&quot;http://dx.doi.org/10.1016/j.earscirev.2009.10.009&quot; rel=&quot;noreferrer&quot;&gt;(2)&lt;/a&gt;&lt;/sup&gt; mostly discredits this theory:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Finally the recent report of a 500-km-diameter impact structure of possible Permian–Triassic age in the Antarctic&lt;sup&gt;&lt;a href=&quot;http://dx.doi.org/10.1029/2008GC002149&quot; rel=&quot;noreferrer&quot;&gt;(1)&lt;/a&gt;&lt;/sup&gt;, is based entirely on satellite gravity measurements, provides no geological context, and completely ignores the absence of any predictable regional and global geological effects from such a large impact event, e.g., the absence of any thick ejecta layer at nearby Antarctic Permian–Triassic boundary sections.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Leaving aside the discussion of whether such a thing caused the formation of the Siberian Traps and thus the P-T mass extinction, &lt;strong&gt;in theory, can an impact on one side of the Earth cause volcanism on its antipode?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also very important, &lt;strong&gt;why would this happen&lt;/strong&gt;? &lt;strong&gt;What's the supposed mechanism that converts short term seismic activity to volcanic activity derived from long term hot spots&lt;/strong&gt;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that I'm not asking about &lt;em&gt;in situ&lt;/em&gt; volcanic activity (such as the case of Sudbury). The impact also has to be reasonable in magnitude: I don't consider the moon-forming event that destroyed the young Earth as a reasonable impact in magnitude.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;(1) von Frese, R. R. B., L. V. Potts, S. B. Wells, T. E. Leftwich, H. R. Kim, J. W. Kim, A. V. Golynsky, O. Hernandez, and L. R. Gaya-Piqué (2009), GRACE gravity evidence for an impact basin in Wilkes Land, Antarctica, &lt;em&gt;Geochem. Geophys. Geosyst.&lt;/em&gt;, 10, Q02014, doi:&lt;a href=&quot;http://dx.doi.org/10.1029/2008GC002149&quot; rel=&quot;noreferrer&quot;&gt;10.1029/2008GC002149&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) Bevan M. French, Christian Koeberl (2010), The convincing identification of terrestrial meteorite impact structures: What works, what doesn't, and why, &lt;em&gt;Earth-Science Reviews&lt;/em&gt;, 98, Issues 1–2, Pages 123-170, doi:&lt;a href=&quot;http://dx.doi.org/10.1016/j.earscirev.2009.10.009&quot; rel=&quot;noreferrer&quot;&gt;10.1016/j.earscirev.2009.10.009&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;edit 18/10/2015&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There was a &lt;a href=&quot;http://dx.doi.org/10.1126/science.aac7549&quot; rel=&quot;noreferrer&quot;&gt;paper published recently in Science&lt;/a&gt; that suggests that this is exactly what happened in the K-Pg extinction event. The Chicxulub increased the intensity of the Deccan volcanism, on the other side of the planet. Here are some links:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://news.sciencemag.org/climate/2015/10/volcanoes-and-asteroid-strike-may-have-done-dinosaurs&quot; rel=&quot;noreferrer&quot;&gt;Volcano-asteroid combo may have done in the dinosaurs&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://arstechnica.com/science/2015/10/could-dino-killing-asteroid-have-pumped-up-giant-volcanoes/&quot; rel=&quot;noreferrer&quot;&gt;Could dino-killing asteroid have pumped up giant volcanoes?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;edit 31/12/2016&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not everyone agrees! For example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://dx.doi.org/10.1130/B31520.1&quot; rel=&quot;noreferrer&quot;&gt;Triggering of the largest Deccan eruptions by the Chicxulub impact: Comment&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2016-12-31T03:22:35.033" LastActivityDate="2016-12-31T03:22:35.033" Title="Can impact events cause widespread volcanic activity on the other side of the planet?" Tags="|geophysics|volcanology|meteorite|hotspot|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="3087" PostTypeId="2" ParentId="3086" CreationDate="2014-12-19T00:30:54.537" Score="7" Body="&lt;p&gt;&lt;strong&gt;Note: this is a part answer, based on recent research and modelling&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There has been considerable research recently in what is known as &lt;strong&gt;antipodal disruption&lt;/strong&gt;, in particular, a group from Princeton University have produced a model that overcomes the main deficiencies of commonly used models that have the Earth as a 'featureless sphere' (&lt;a href=&quot;http://www.princeton.edu/main/news/archive/S31/90/32S94/&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;)(&lt;a href=&quot;http://gji.oxfordjournals.org/content/187/1/529.full&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;).  Simulations using a symmetric spherical Earth produce a deceptively large peak at the antipode (&lt;a href=&quot;http://gji.oxfordjournals.org/content/187/1/529.full&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;) - this is often cited as being some form of proof for the P-T example that you provided in the question and an antipodal relationship between the Deccan Traps and the Chicxulub crater (&lt;a href=&quot;http://www.princeton.edu/main/news/archive/S31/90/32S94/&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the Princeton team's simulation (&lt;a href=&quot;http://www.princeton.edu/main/news/archive/S31/90/32S94/&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;), (&lt;a href=&quot;http://gji.oxfordjournals.org/content/187/1/529.full&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;) show that there ought to be an antipodal effect, but when the elliptical shape and the heterogeneity of the surface is taken into account - where the waves end up and their displacement when they get there are quite different to the spherical models (&lt;a href=&quot;http://www.princeton.edu/main/news/archive/S31/90/32S94/&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;), to the order of 4 times &lt;em&gt;less&lt;/em&gt; displacement and the antipode effects are not on a point source (&lt;a href=&quot;http://gji.oxfordjournals.org/content/187/1/529.full&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This results in a disagreement with the Deccan Traps-Chixculub relationship, as shown in the late Cretaceous model below, from (&lt;a href=&quot;http://www.princeton.edu/main/news/archive/S31/90/32S94/&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/9pKy1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This has implications for not only seismicity, but for volcanism and hot spot activity, due to the modelled impact seismic waves (across the surface and through the Earth) showing to be unfocused and scattered, this results in less severe ground displacement, tsunamis, and seismic and volcanic activity than previously theorized. Their models showed that the antipodal region had 'chimneys' of peak stress, strain and velocity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meschede et al. 2011 (&lt;a href=&quot;http://gji.oxfordjournals.org/content/187/1/529.full&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;) conclude from their model that there would be greater seismicity in the region around the antipodal 'chimneys', this increase in seismicity can trigger volcanism, and even though the impact energy has been modelled to be insufficient (by several orders of magnitude) to induce melting to form an antipodal hotspot.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some ongoing research by Hagstrum, 2005 (&lt;a href=&quot;http://www.mantleplumes.org/WebDocuments/Antip_hot.pdf&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;) has suggested that oceanic impacts may result in hotspot/large igneous province antipodal pairs, this is due to, according to Hagstrum, oceanic crust having a greater seismic efficiency that continental crust. The mechanism is, according to Hagstrum,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;an&#xA;  inherently antipodal mechanism of hotspot formation&#xA;  is proposed in which one hotspot forms at an oceanic&#xA;  large-body impact site and a second hotspot and&#xA;  possible LIP are formed from seismic energy focused&#xA;  in the lithosphere and upper asthenosphere at the&#xA;  impact’s antipode.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, it is not clear if the non-spherical heterogenous nature of the Earth's lithosphere was taken into account, given that, as stated, the impact energy is insufficient to cause melting, Ivanov and Melosh (&lt;a href=&quot;http://www.lpi.usra.edu/meetings/largeimpacts2003/pdf/4062.pdf&quot; rel=&quot;noreferrer&quot;&gt;4&lt;/a&gt;) state that the seismic mechanism may &lt;em&gt;contribute&lt;/em&gt; as a trigger for a &quot;pregnant&quot; hotspot to activate, &lt;strong&gt;not&lt;/strong&gt; through melting, but through increased seismicity (fracturing rocks etc).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;em&gt;Note, the use of &quot;pregnant&quot; is their words, not mine&lt;/em&gt;) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Conclusion&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The models created by Meschede et al. (&lt;a href=&quot;http://gji.oxfordjournals.org/content/187/1/529.full&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;) have found that it is theoretically possible for localised antipodal volcanism to occur, but this volcanism would not necessarily be the &lt;em&gt;direct&lt;/em&gt; result of the impact itself, but due to the &lt;em&gt;contribution&lt;/em&gt; of an increase in antipodal seismicity (increased earthquakes fracturing rocks in the lithosphere etc). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meschede et al. (&lt;a href=&quot;http://gji.oxfordjournals.org/content/187/1/529.full&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;) contend that their model indicates that the impact energy is very much insufficient to result in a sustained mantle plumes and hotspot volcanic regimes as in the previous models.  However, there is still ongoing research about the impact energy &lt;em&gt;contribution&lt;/em&gt; to the formation of hotspots and 'traps', particularly for oceanic impacts (&lt;a href=&quot;http://www.mantleplumes.org/WebDocuments/Antip_hot.pdf&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;), but this is very much uncertain (&lt;a href=&quot;http://gji.oxfordjournals.org/content/187/1/529.full&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;) and unlikely to be the direct cause (&lt;a href=&quot;http://www.lpi.usra.edu/meetings/largeimpacts2003/pdf/4062.pdf&quot; rel=&quot;noreferrer&quot;&gt;4&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.princeton.edu/main/news/archive/S31/90/32S94/&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;) Kelly, 2011, &lt;a href=&quot;http://www.princeton.edu/main/news/archive/S31/90/32S94/&quot; rel=&quot;noreferrer&quot;&gt;Impact study: Princeton model shows fallout of a giant meteorite strike&lt;/a&gt;, &lt;em&gt;News at Princeton, Princeton University&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://gji.oxfordjournals.org/content/187/1/529.full&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;) Meschede et al. 2011, &lt;a href=&quot;http://gji.oxfordjournals.org/content/187/1/529.full&quot; rel=&quot;noreferrer&quot;&gt;Antipodal focusing of seismic waves due to large meteorite impacts on Earth&lt;/a&gt;, &lt;em&gt;Geophysical Journal International&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.mantleplumes.org/WebDocuments/Antip_hot.pdf&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;) Hagstrum, 2005, &lt;a href=&quot;http://www.mantleplumes.org/WebDocuments/Antip_hot.pdf&quot; rel=&quot;noreferrer&quot;&gt;Antipodal hotspots and bipolar catastrophes: Were oceanic&#xA;large-body impacts the cause?&lt;/a&gt;, &lt;em&gt;Earth and Planetary Science Letters&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.lpi.usra.edu/meetings/largeimpacts2003/pdf/4062.pdf&quot; rel=&quot;noreferrer&quot;&gt;4&lt;/a&gt;) Ivanov and Melosh, 2003, &lt;a href=&quot;http://www.lpi.usra.edu/meetings/largeimpacts2003/pdf/4062.pdf&quot; rel=&quot;noreferrer&quot;&gt;Large Scale Impacts and Triggered Volcanism&lt;/a&gt;, in &lt;em&gt;Large Meteorite Impacts&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-12-20T09:54:01.510" LastActivityDate="2014-12-20T09:54:01.510" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="3088" PostTypeId="1" CreationDate="2014-12-19T01:36:02.987" Score="12" ViewCount="2491" Body="&lt;p&gt;I'm doing a project in which I'm analyzing earthquake seismogram waves. I used a program to graph the exact amplitudes and how they changed over the course of a single earthquake. For the project I need to incorporate calculus, so I was wondering, what does finding the derivative of amplitude do? And what does finding the integral get you? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The integral is the area under the entire wavelength, but I was wondering if it was equivalent to energy released, or some sort of geology/physics thing I didn't understand. Thank you.&lt;/p&gt;&#xA;" OwnerUserId="1356" LastEditorDisplayName="user889" LastEditDate="2014-12-19T03:03:58.513" LastActivityDate="2015-06-28T21:29:36.463" Title="What do the derivative or the integral of amplitude of a seismogram mean?" Tags="|geophysics|geology|plate-tectonics|seismology|earthquakes|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3089" PostTypeId="2" ParentId="3088" CreationDate="2014-12-19T03:04:02.577" Score="12" Body="&lt;p&gt;This is a very simple answer, and it depends on the what the seismometer is measuring. I'm assuming you mean the time derviative/intdegral  $\frac\partial{\partial{}t}$ or  $\int{dt}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most seismometers measure displacement over time or velocity over time (series). So taking the time derivative will give you the spectral velocity or the spectral acceleration respectively when you take their derivatives.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you take the integral of displacement, you calculate the total area displaced over time, and when you take the integral of velocity, you calculated the displacement. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's all physics 101 really!   &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2014-12-19T03:04:02.577" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3090" PostTypeId="2" ParentId="3060" CreationDate="2014-12-19T04:39:22.937" Score="10" Body="&lt;p&gt;A very good analysis looking at the 3% relationship is an article by &lt;a href=&quot;http://dx.doi.org/10.1175/1520-0485(1983)013%3C0524:SWAWIC%3E2.0.CO;2&quot; rel=&quot;noreferrer&quot;&gt;Weber (1983)&lt;/a&gt;. His main result is that: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We assume a fully developed sea, and take the eddy viscosity to be proportional to the friction velocity times a characteristic depth. Hence the total current (Ekman current plus wave-induced current) can be expressed as functions of the wind speed. The results show that the magnitude of the total surface current lies between 3.1 and 3.4% of the wind speed at 10 m height for winds between 5 and 30 m s&lt;sup&gt;−1&lt;/sup&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The idea is that by including both the Ekman current (induced by the mean wind stress at the surface) and the wave-induced current (Stokes drift), the resulting total surface velocity can be easily represented as a function of wind velocity at 10 meters. Both Ekman and wave-induced currents are about the same size and add up to be around 3% of the wind speed. The assumptions include the full range for Ekman dynamics (homogeneous, not affected by boundaries), plus some about waves (non-decaying, small amplitude). In the real ocean, eddy viscosity is vertically variable, but, as it is the case with Ekman dynamics, the approximation is quite close to what is observed in the ocean. The approximations that Weber used are valid for a large range of wind values (5-30 m s&lt;sup&gt;−1&lt;/sup&gt;) and they break down in weak wind (not fully developed waves) and strong wind conditions (whitecapping, wave breaking).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://dx.doi.org/10.1175/1520-0485(1983)013%3C0524:SWAWIC%3E2.0.CO;2&quot; rel=&quot;noreferrer&quot;&gt;Weber, J. E., 1983:&lt;/a&gt; Steady Wind- and Wave-Induced Currents in the Open Ocean. J. Phys. Oceanogr., 13, 524–530. &lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2014-12-19T14:48:18.333" LastActivityDate="2014-12-19T14:48:18.333" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3091" PostTypeId="1" AcceptedAnswerId="3092" CreationDate="2014-12-19T19:55:13.553" Score="13" ViewCount="1390" Body="&lt;p&gt;A rogue wave is, according to &lt;a href=&quot;http://oceanservice.noaa.gov/facts/roguewaves.html&quot; rel=&quot;noreferrer&quot;&gt;NOAA&lt;/a&gt;, &quot;a large, unexpected and dangerous&quot; oceanic wave.  These are also known as 'killer' or 'freak' waves and have been a part of folklore of the past and observation of the present - such as in the rather terrifying example below (from &lt;a href=&quot;http://gcaptain.com/mariners-guide-waves/&quot; rel=&quot;noreferrer&quot;&gt;gcaptain.com&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/mTXua.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Caption:&lt;/strong&gt; A wall of water approaches the Stolt Surf in Oct. 1977 Photo:&#xA;  Karsten Petersen, www.global-mariner.com&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There are a number of theories as to how these form, according to the NOAA page linked above, it can be a result of constructive interference or focusing of wave energy.  Another theory reported in the Scientific American Blog entry from 2009 &lt;a href=&quot;http://www.scientificamerican.com/article/rogue-waves-ocean-energy-forecasting/&quot; rel=&quot;noreferrer&quot;&gt;The Real Sea Monsters: On the Hunt for Rogue Waves&lt;/a&gt; is that &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;If a wave propagates from east to west, and the current moves west to east, then a wave starts to build up,&quot; says Wu, who studies wave–current interactions in a 15-meter pool. The wave basically climbs the current's wall, rising out of what appears to be nowhere. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This question is not so much based on the actual mechanism behind rogue waves, but how we can use these models to forecast their occurrence, going from the theoretical models discussed in the Scientific American blog to develop actual proven forecast models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is the status of research in forecasting oceanic rogue waves?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-12-23T05:49:38.507" LastActivityDate="2018-05-03T09:28:19.707" Title="Forecasting oceanic rogue waves" Tags="|ocean|oceanography|ocean-currents|waves|solitary-waves|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="3092" PostTypeId="2" ParentId="3091" CreationDate="2014-12-20T00:10:41.713" Score="12" Body="&lt;p&gt;There are few known mechanisms that lead to the generation of Rogue waves, such as the ones you mentioned, but essentially all Rogue waves are the due to the nonlinear wave dispersion characteristics of large groups of waves. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can imagine one approach to predicting the emergence of such waves is to simulate the evolution of initial wave states with Navier-Stokes based wave models that capture the nonlinear dynamics involved in real time. However, with the limited computational power and numerical techniques we have today, that is currently impossible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I think the question is: Do we know of specific signatures in the ocean wave climate, which ultimately give rise to these so called &quot;walls of water&quot;? Presumably these wave patterns could serve as early warning indicators of an upcoming rogue wave event. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is indication that the emergence of solitons from modulational instability or dispersion of wave packets occurs in consonance with nonlinear effects and nonlocal coupling giving rise to Roge waves. Thus, an approach based on the spectral analysis of the sea-state as a whole or of particular envelopes of propagating waves may hint at particular wave-field patterns that originate Rogue waves. Please see the sources below for more information on the current state of the art. However, at the moment the answer is that forecasting Rogue waves is still much of an unknown.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Akhmediev, Nail, et al. &quot;Rogue Waves: Early Warning vs Forecast.&quot;&#xA;  (2011).&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Akhmediev, N., et al. &quot;Early detection of rogue waves in a chaotic&#xA;  wave field.&quot; Physics Letters A 375.33 (2011): 2999-3001.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Onorato, Miguel, et al. &quot;Rogue waves and their generating mechanisms&#xA;  in different physical contexts.&quot; Physics Reports 528.2 (2013): 47-89.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="200" LastActivityDate="2014-12-20T00:10:41.713" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="3093" PostTypeId="2" ParentId="2521" CreationDate="2014-12-20T04:06:19.937" Score="4" Body="&lt;p&gt;The respiration of plants is not evenly distributed through seasons since the northern and southern hemisphere have a different amount of land and plants.  The southern hemisphere has far less land. In the northern winter, the carbon released increases and then by ~May the northern hemisphere has enough carbon uptake (due to increased photosynthesis) to cause a dip in the $\ce{CO2}$ record.  Then summer in the north ends... autumn commences, and net $\ce{CO2}$ starts to rise again. &lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorDisplayName="user889" LastEditDate="2014-12-20T12:02:19.093" LastActivityDate="2014-12-20T12:02:19.093" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3094" PostTypeId="2" ParentId="2487" CreationDate="2014-12-20T04:10:23.940" Score="3" Body="&lt;p&gt;There have been several studies regarding the separation of volcanic and water-wave (surf) microseismic traces, recently a study was performed exactly as you asked - using and comparing data from several sensors. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A recent study at Pagan Volcano in the Northern Mariana Islands (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2013GL058954/abstract&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt;) demonstrated multiparameter seismo-acoustic observations of long-period signals from seismic, infrasound and buoy data can not only determine the azimuth to the source of the mcroseism disturbance, but can provide a means to compare the frequency typical of surf and those that are 'normal' for the volcano.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the major differences they found was when a typhoon passed 770km away from the sensors, these clearly showed the difference in the signal that ocean waves have on local surf induced microseisms - causing a peak that is not present on the volcanic microseism (as the volcano itself is not directly affected by the surf). In fact, the storm track could be tracked, something that was also done during Superstorm Sandy (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0012821X13005785&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;) - which presents another signal that is very different to volcanic microseisms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The research and observations suggest that a feasible way of determining the origin of the sources to microseisms is to have an array of types and spacing of sensors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2013GL058954/abstract&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt;) Lyons et al. 2014, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2013GL058954/abstract&quot; rel=&quot;nofollow&quot;&gt;Distinguishing high surf from volcanic long-period earthquakes&lt;/a&gt;, &lt;em&gt;Geophysical Research Letters&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0012821X13005785&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;) Sufri et al. 2014, &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0012821X13005785&quot; rel=&quot;nofollow&quot;&gt;Microseisms from Superstorm Sandy&lt;/a&gt;, &lt;em&gt;Earth and Planetary Science Letters&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-12-21T03:21:58.390" LastActivityDate="2014-12-21T03:21:58.390" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3095" PostTypeId="2" ParentId="182" CreationDate="2014-12-20T13:31:50.403" Score="8" Body="&lt;p&gt;This is a partial answer detailing some of the recent research in lunar atmospheric tides.  Many of which go beyond the 27.3 and 13.6 day cycles discussed in the &lt;a href=&quot;http://link.springer.com/article/10.1007%2FBF02918750&quot; rel=&quot;noreferrer&quot;&gt;Guoqing, 2005&lt;/a&gt; paper, referenced in your question.  There has been some considerable research in this in recent years (an example is &lt;a href=&quot;http://scholar.google.com.au/scholar?as_ylo=2013&amp;amp;q=lunar%20atmospheric%20tides&amp;amp;hl=en&amp;amp;as_sdt=0,5&quot; rel=&quot;noreferrer&quot;&gt;this list&lt;/a&gt; from Google Scholar of research since 2013).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A couple of examples are explained below that show that all manner of lunar cycles seem to have an effect on the Earth's atmosphere, generating a complexity of tides that tidally affect all layers of the atmosphere.  As we've been able to take long term measurements of various atmospheric parameters (most notably temperature, pressure and velocity) we have been able to come across patterns that suggest that several lunar cycles have made an imprint on them - in a way, suggesting that all lunar cycles have an affect on our atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The lunar semi-diurnal cycle has been found to have a definite signature in the amplitude and phases of the temperature field of parts of the atmosphere between 20-120km altitude, according to research presented in the article &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2013JD019818/abstract&quot; rel=&quot;noreferrer&quot;&gt;A global view of the atmospheric lunar semidiurnal tide&lt;/a&gt; (Paulino et al. 2013) with the most pronounced signature observed in the lower thermosphere region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Observations made between 1947-1994 in the article &lt;a href=&quot;http://benthamopen.com/toascj/articles/V007/TOASCJ130415001.pdf&quot; rel=&quot;noreferrer&quot;&gt;Long-Term Lunar Atmospheric Tides in the Southern Hemisphere&lt;/a&gt; (Wilson and Siderankov, 2013) have detected 4 roughly equidistant standing-wave summertime patterns with mean sea level pressure (MSLP) and sea-surface temperature (SST) consistent with being influenced by the 18.6 year Draconic lunar atmospheric cycle.  Superimposed on these is evidence of the SST's being affected longterm by the &lt;a href=&quot;http://en.wikipedia.org/wiki/Supermoon&quot; rel=&quot;noreferrer&quot;&gt;Perigee-Syzygy (or 'supermoon') lunar cycle&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A consequence is that the standing-wave pattern of the MSLP will interact and cause abnormal atmospheric pressure when passing over the &lt;a href=&quot;http://en.wikipedia.org/wiki/South_Pacific_High&quot; rel=&quot;noreferrer&quot;&gt;semi-permanent South Pacific subtropical high&lt;/a&gt; roughly every 4.5 years, the consequences are that these affect the strength of the East-Pacific trade winds and according to the authors, may lead to conditions that &quot;preferentially favor the onset of La Niña/El Niño events.&quot; &lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="111" LastEditDate="2014-12-21T21:41:05.280" LastActivityDate="2014-12-21T21:41:05.280" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3096" PostTypeId="1" CreationDate="2014-12-20T19:20:31.810" Score="15" ViewCount="5291" Body="&lt;p&gt;I know some planets have storms akin to what we have on Earth although obviously varying in nature. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was wondering if other planets have earthquakes? Since this comes down to plate tectonics (right?), I guess I am also asking if other planets have plate tectonics. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously, a planet like Uranus or Neptune wouldn't because they are gas, so I am restricting it to terrestrial ones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried to look this up on Wikipedia, but I couldn't think of a word besides non-earthquake or just quake but those didn't turn up any results. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What frequency do different kinds of seismic activity appear throughout the universe?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="1260" LastEditorUserId="725" LastEditorDisplayName="user889" LastEditDate="2017-03-02T08:33:04.610" LastActivityDate="2018-11-09T13:03:23.543" Title="Do other terrestrial planets have &quot;earthquakes&quot;?" Tags="|seismology|earthquakes|planetary-science|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="3097" PostTypeId="2" ParentId="3096" CreationDate="2014-12-20T19:47:43.243" Score="8" Body="&lt;p&gt;For terminology, &quot;Earth&quot;quakes might be replaced with &quot;seismic activity&quot; since earthquakes are by definition restricted to the Earth.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Technically speaking the other terrestrial planets in our solar system are not active in terms of plate tectonics.  Mercury undergoes rapid heating/cooling depending on its rotation and exposure to the Sun which must lead to some type of seismic activity, though likely very small magnitude.  I don't know of any seismic anomalies recorded on Venus or Mars but certainly there must be some type of activity from time to time due to changes in magma.  Magma - related quakes, though, are typically not as strong as quakes from the dynamics of plate tectonics.  For instance, Hawaii has seismic activity due to the volcanos, which produce maximum seismic activity that is orders of magnitude less than what two plates (e.g. a fault line) rubbing against eachother produce.  Though, the magmatic processes lead to a higher quake frequency.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would wager that the moon of Jupiter, Io, and Earth have the strongest seismic activity in our solar system.  &lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2014-12-20T21:49:07.333" LastActivityDate="2014-12-20T21:49:07.333" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3098" PostTypeId="2" ParentId="2845" CreationDate="2014-12-20T22:39:41.603" Score="5" Body="&lt;p&gt;Geothermal reservoirs are very different from hydrocarbon reservoirs. A geothermal reservoir is made of highly fractured igneous/metamorphic rocks which have low intrinsic permeability. Fluids get heated as they flow through fractures to temperatures well above the boiling point of water. The reason they flow is because of thermal gradients which causes convection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oil/gas reservoirs are contained in sedimentary rocks which have much higher permeabilities and relatively lower temperatures. Also hydrocardon reservoirs in most cases are confined. In theory you can utilize some of the heat in the depleted reservoir by injecting cold water and utilizing the hot water as done in an enhanced geothermal system or EGS. But it wont be efficient as the reservoir will loose heat quickly. And since the fluids extracted will still contain some hydrocarbons you have the additional headache of disposing them properly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: I am talking about geothermal reservoirs of the kind you see in Western US (e.g., The Geysers), Iceland, Philippines, etc.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastActivityDate="2014-12-20T22:39:41.603" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3099" PostTypeId="2" ParentId="3088" CreationDate="2014-12-20T23:50:07.323" Score="5" Body="&lt;p&gt;It really depends on what type of seismometer you are using. Seismometers are mechanical/electronic instruments intended to sense ground motion, but the trace recorded on the seismogram depends on the design of the seismometer. Classical modern seismometers are actually a driven damped oscillator. You need to know the response of the seismometer to reduce it to ground displacement, velocity, or acceleration. Seismometers are orientation-dependent, and typically three seismometers are required to measure all three components of ground motion. Seismometer response is frequency dependent. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Like the development of microscopes, and telescopes, the development of seismic monitoring instruments has a long history and improvements in design have led to advances in the science. For more information about the development of seismometers through history, see this article about &lt;a href=&quot;http://earthquake.usgs.gov/learn/eqmonitoring/&quot;&gt;Earthquake Monitoring&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorUserId="178" LastEditDate="2014-12-20T23:59:09.140" LastActivityDate="2014-12-20T23:59:09.140" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3100" PostTypeId="1" CreationDate="2014-12-21T04:41:54.063" Score="11" ViewCount="28677" Body="&lt;p&gt;Australia's Great Dividing Range is the largest mountain range on the continent, running down the length of the eastern part of the continent, as shown in the &lt;a href=&quot;http://www.ga.gov.au/scientific-topics/hazards/flood/basics/gallery&quot; rel=&quot;noreferrer&quot;&gt;Geoscience Australia&lt;/a&gt; map as a dark line, below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/XMbWF.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The tallest peak in the range is &lt;a href=&quot;http://www.ga.gov.au/scientific-topics/geographic-information/landforms/highest-mountains#heading-1&quot; rel=&quot;noreferrer&quot;&gt;Mt. Kosciuszko at 2228 m asl.&lt;/a&gt;  The &lt;a href=&quot;http://en.wikipedia.org/wiki/Great_Dividing_Range#History&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia entry&lt;/a&gt; is rather vague about the formation, with&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Great Dividing Range was formed during the Carboniferous period—some 300 million years ago—when Australia collided with what is now parts of South America and New Zealand. The range has experienced significant erosion since.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;it is particularly vague regarding the question - &lt;strong&gt;What is the tectonic setting for the formation of the Great Dividing Range in Australia?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2023-08-19T03:45:15.243" Title="What is the tectonic setting for the formation of the Great Dividing Range in Australia?" Tags="|plate-tectonics|earth-history|mountain-building|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3101" PostTypeId="1" AcceptedAnswerId="3112" CreationDate="2014-12-21T07:40:20.883" Score="17" ViewCount="427" Body="&lt;p&gt;What is the maximum period of time into the future that an El Niño event can be forecasted with reasonable accuracy and what are the limitations in predicting the time limit?&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorUserId="192" LastEditDate="2014-12-21T22:38:40.327" LastActivityDate="2014-12-29T19:29:57.457" Title="What is the predictability of El Niño/La Niña?" Tags="|meteorology|oceanography|enso|climate-models|predictability|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="3102" PostTypeId="2" ParentId="762" CreationDate="2014-12-21T11:55:44.740" Score="0" Body="&lt;p&gt;In my opinion, the role of water in plate tectonics is to serve the plate driving mechanism. A spreading ridge is heated from bottom and effectively cooled on top by water.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Moon/Sun induced deformations of the ridge have to cause hot material to be transported upwards according to the second low of thermodynamics. Basically, the transported material cools and solidifies thus pushing the sides of the ridge apart on the ridge deformations induced by Moon/Sun. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I called the theory &quot;Active Fracture Tectonics&quot;. You may wish to look through my blogs &lt;a href=&quot;http://sukhotinsky.blogspot.com/&quot; rel=&quot;nofollow&quot;&gt;sukhotinsky.blogspot.com&lt;/a&gt; or &lt;a href=&quot;http://divergent-boundaries.blogspot.com/&quot; rel=&quot;nofollow&quot;&gt;divergent-boundaries.blogspot.com&lt;/a&gt; to get the idea in details.&lt;/p&gt;&#xA;" OwnerUserId="1360" LastActivityDate="2014-12-21T11:55:44.740" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3103" PostTypeId="2" ParentId="762" CreationDate="2014-12-21T16:38:38.440" Score="-1" Body="&lt;p&gt;The short answer is that we don't really know for sure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the larger scheme of things, a plate is simply a thin (and cool) boundary layer at the top of a convecting cell. Plates are a result of mantle convection and their composition will have little effect on convection itself. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the same time water tends to lower melting point of mantle rocks which can have many important consequences, e.g., back arc volcanism (as water gets transported to great depths during subduction), onset of instabilities etc.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastActivityDate="2014-12-21T16:38:38.440" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="3105" PostTypeId="2" ParentId="762" CreationDate="2014-12-21T22:10:57.670" Score="10" Body="&lt;p&gt;One way of looking at this question is to determine if Earth would possess an active-lid (multiple plate), stagnant-lid (single plate) or an intermediary state (e.g. episodic or sluggish) tectonic regime.  This is one of the reasons comparisons are often made with Venus, especially in regards to the main difference been that Venus has a stagnant-lid with possible episodic active tectonic regime (see question and answer to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2249/can-venus-be-considered-to-be-tectonically-active&quot;&gt;Can Venus be considered to be tectonically active?&lt;/a&gt;, compared to Earth's active-lid tectonic regime.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, there are other differences between Venus and Earth that also may account for the differences in tectonic regimes, asides from the relative absence of water on Venus. Some modelling by Bouffard, (2013) indicated that different plastic yield strengths of lithospheric rheology could account for the different tectonic regimes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How water interacts oceanic lithosphere is a vital consideration for this kind of question, considering that most spreading ridges and all subduction zones are based on the oceanic lithosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;This answer is based on how the absence of water may have prevented a key &lt;em&gt;theorised&lt;/em&gt; tectonic mechanism from even starting.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A crucial role for water is modelled by Regenauer et al. (2001) for the initiation of subduction and as they assert the beginning of plate tectonics, based on the theory that long term build up of sediment at a &lt;a href=&quot;http://geology.uprm.edu/Morelock/marg.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;passive continental-oceanic boundary&lt;/a&gt; (e.g North American east coast) may have caused the strain to build up to a point where the oceanic crust 'breaks' and starts subducting, as shown in the diagram below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/j6UQv.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://records.viu.ca/~earles/subduction-water-oct01.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the absence of water, this process of subduction initiation (should it be true) could not have started; as the authors believe could be the case for Venus where volcanism is evident, but the mechanism appears to be hotspot activity through the current stagnant-lid tectonic regime observed there - &lt;em&gt;if&lt;/em&gt; this theory were true, then the absence of water would mean that Earth would potentially have had a stagnant-lid, punctured by hotspot activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bouffard, 2013, &lt;a href=&quot;http://www.ens-lyon.fr/DSM/SDMsite/M2/stages_M2/Bouffard2013.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Role of water in the tectonics of Earth and Venus&lt;/a&gt;, &lt;em&gt;University of Lyon&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regenaeur et al. 2001, &lt;a href=&quot;http://www.sciencemag.org/content/294/5542/578&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Initiation of Subduction: Criticality by Addition of Water?&lt;/a&gt; &lt;em&gt;Science&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-12-22T14:28:58.627" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3106" PostTypeId="5" CreationDate="2014-12-21T22:51:30.307" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-12-21T22:51:30.307" LastActivityDate="2014-12-21T22:51:30.307" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3107" PostTypeId="4" CreationDate="2014-12-21T22:51:30.307" Score="0" Body="A tag for questions about conceptual, analytical or numerical models used in Earth science disciplines." OwnerUserId="192" LastEditorUserId="192" LastEditDate="2014-12-21T23:29:36.237" LastActivityDate="2014-12-21T23:29:36.237" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3108" PostTypeId="5" CreationDate="2014-12-21T22:54:01.573" Score="0" Body="&lt;p&gt;Geophysics is a broad subject that studies many properties of the Earth, such as its shape, gravity, magnetic field, internal structure and dynamics. It also includes fluid dynamics of external envelopes (hydrosphere and atmosphere) and the study of similar problems on other planets.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="2470" LastEditDate="2019-12-06T04:06:59.140" LastActivityDate="2019-12-06T04:06:59.140" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="3109" PostTypeId="4" CreationDate="2014-12-21T22:54:01.573" Score="0" Body="Geophysics is a subject of natural science concerned with the physical processes and physical properties of the Earth and its surrounding space environment." OwnerUserId="192" LastEditorUserId="192" LastEditDate="2014-12-21T23:29:40.823" LastActivityDate="2014-12-21T23:29:40.823" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3110" PostTypeId="1" AcceptedAnswerId="3180" CreationDate="2014-12-22T01:32:25.057" Score="7" ViewCount="117" Body="&lt;p&gt;In the article &lt;a href=&quot;http://alaska.usgs.gov/staff/geology/bradley/pubs/2008_Bradley_passive_margins.pdf&quot;&gt;Passive margins through earth history&lt;/a&gt; (Bradley, 2008), a passive margin is defined as:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;a synonym for the bulkier Atlantic-type&#xA;  margin, trailing-edge margin, rifted margin, or divergent margin. A&#xA;  passive margin is one formed by rifting followed by seafloor&#xA;  spreading, so that the resulting plate consists of both continental&#xA;  and oceanic lithosphere, welded across an igneous contact. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In the research, the author determined that in terms of the abundance of passive margins that the distribution varied with time, from the article:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;They were abundant at&#xA;  1900–1890, 610–520, and 150–0 Ma, scarce at ca. 2445–2300, 1600–1000, and 300–275 Ma, and absent&#xA;  before ca. 3000 Ma and at 1740–1600.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The absence of passive margins older than 3000 million years is uncertain, possibly due to lack of preservation; however the absence between 1740-1600 million years is described vaguely by the author as being the result of&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;One by one, each of these margins collided&#xA;  with something, leaving no passive margins at all&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;possibly related to the coalescencing of the &quot;supercontinent&quot; Nuna - but the total absence is not noted in association with other supercontinents (Rodinia, Pangaea etc).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What does the absence of passive margins between 1740-1600 million years ago tell us about the tectonic environment at that time?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2015-01-03T04:34:17.250" Title="What does the absence of passive margins between 1740-1600 million years ago tell us about the tectonic environment at that time?" Tags="|plate-tectonics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3111" PostTypeId="2" ParentId="3045" CreationDate="2014-12-22T05:35:32.417" Score="4" Body="&lt;p&gt;Based on your video, it does appear to be a non-rotating wall cloud - but admittedly, it is hard to definitively determine, mainly as it is hard to see any updraft.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another example of a non rotating wall cloud is from NOAA's &lt;a href=&quot;http://www.crh.noaa.gov/lmk/?n=cloud_classification&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cloud Classification and Characteristics&lt;/a&gt; page (image below):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/iMwwM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and their description:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The lowering denotes a storm's updraft where rapidly rising air causes lower pressure just below the main updraft, which enhances condensation and cloud formation just under the primary cloud base. Wall clouds take on many shapes and sizes. Some exhibit strong upward motion and cyclonic rotation, leading to tornado formation, while others do not rotate and essentially are harmless.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Alternatively and given the possible absence of the characteristic updraft of a wall cloud, it could be a scud cloud, similar to the one shown below&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/GAlFJ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.wunderground.com/wximage/Doove4cane/66?gallery=&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A &lt;strong&gt;scud cloud&lt;/strong&gt; is defined by &lt;a href=&quot;http://www.accuweather.com/en/weather-glossary/what-are-scud-clouds/5507655&quot; rel=&quot;nofollow noreferrer&quot;&gt;Accuweather&lt;/a&gt; as being:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;ow, ragged and wind-torn cloud fragments, usually not attached to the thunderstorm base. They are often seen in association with, and behind, gust fronts.&#xA;  Scud clouds DO NOT produce severe weather. &lt;strong&gt;Scud clouds are often mistaken for wall clouds&lt;/strong&gt; and tornadoes, especially when attached to the thunderstorm base.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A handy tip to tell the difference between a wall cloud and a scud cloud is (according to Accuweather):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;to watch their relative position with respect to the rain area: scud&#xA;  clouds move away from the rain area while wall clouds maintain the&#xA;  same relative distance.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;A video tutorial is included in the Accuweather site&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2014-12-23T03:32:33.283" LastActivityDate="2014-12-23T03:32:33.283" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3112" PostTypeId="2" ParentId="3101" CreationDate="2014-12-22T07:43:29.667" Score="12" Body="&lt;p&gt;All season forecast systems are subject to uncertainty. The uncertainty arises from an imperfect initial state, such as initial conditions, and from imperfect models, such as uncertainty due to, numerical methods, parametric models, data sampling. Forecasting systems utilize ensembles and their spread to quantify uncertainty. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;See the spread in forecasts for El Niño produced by a number of international models:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/xF44L.jpg&quot; alt=&quot;El Niño Forecasts&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When considering large scale processes varying on interannual scales ENSO, which is the coupled process of El Niño/La Niña SST anomalies and the Southern Oscillation, is relatively well predictable. However, the fidelity of the forecasting is modulated by the season, the phase and intensity of ENSO. For example, there is a decrease in skill during the so called &quot;spring predictability barrier&quot; where, during the boreal spring when SST anomalies are abnormally variable. Model drift (such as SST drift as the forecast progresses) and bias especially for a couple-model such as the ENSO, is a very real issue. After only a season the bias inherent in the results renders the forecasting unreliable to the point where the model may be unable to recognize different types of ENSO (such as classical East Pacific versus central Pacific ENSO events). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So unfortunately at this time your specific question is still very hard to answer with any degree of satisfactory precision. But at least we know that it is not more than one season in the future.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alves, Oscar, et al. &quot;Seasonal and decadal prediction.&quot; Operational Oceanography in the 21st Century. Springer Netherlands, 2011. 513-542.&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2014-12-29T19:29:57.457" LastActivityDate="2014-12-29T19:29:57.457" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3113" PostTypeId="2" ParentId="2264" CreationDate="2014-12-22T12:12:43.760" Score="3" Body="&lt;p&gt;Just to add to gerrit's answer and as the question does not specify a hemisphere, noctilucent clouds are also visible in the Southern Hemisphere, which according to the Australian Antarctic Division (AAD) webpage &lt;a href=&quot;http://www.antarctica.gov.au/about-antarctica/environment/atmosphere/noctilucent-clouds&quot; rel=&quot;nofollow noreferrer&quot;&gt;Noctilucent clouds&lt;/a&gt;, but with some differences to those observed in the Northern Hemisphere - predominantly in Antarctica and are viewable even during the southern summer when the sun is between 6 and 16 degrees below the horizon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The picture below is from the AAD, Antarctic Davis base, when the sun was 10 degrees below the horizon:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/9Ggvl.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There have been less observations in the Southern Hemisphere due there being less populated landmasses at the best viewing latitudes.  According to the Australian Geographic article &lt;a href=&quot;http://www.australiangeographic.com.au/topics/science-environment/2011/02/rare-shining-clouds-linked-to-climate-change/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rare 'shining' clouds linked to climate change&lt;/a&gt;, the best places to view the clouds are either on a ship, Antarctica and southern Argentina and Chile in summer.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-12-22T12:12:43.760" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3114" PostTypeId="1" CreationDate="2014-12-22T12:46:21.853" Score="10" ViewCount="194" Body="&lt;p&gt;In reading about &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2264/where-can-we-see-the-noctilucent-clouds&quot;&gt;observing noctilucent clouds&lt;/a&gt;, several articles about this phenomena, such as Science Daily's &lt;a href=&quot;http://www.sciencedaily.com/releases/2007/04/070410131926.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Spectacular 'Night-shining' Clouds Could Be A Harbinger Of Climate Change&lt;/a&gt;, suggest that changes in their frequency and latitudinal-occurrences may be linked to anthropogenic climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is there evidence of a link between anthropogenic climate change and changes in the frequency of noctilucent cloud occurrences?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-01-01T02:45:39.597" Title="Noctilucent clouds and anthropogenic climate change" Tags="|atmosphere|climate-change|clouds|upper-atmosphere|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3115" PostTypeId="1" AcceptedAnswerId="3116" CreationDate="2014-12-22T15:26:09.690" Score="11" ViewCount="4563" Body="&lt;p&gt;Sedimentary rocks in &lt;a href=&quot;http://en.wikipedia.org/wiki/Akilia&quot;&gt;Akilia&lt;/a&gt; or at &lt;a href=&quot;http://dx.doi.org/10.1038/35051550&quot;&gt;Hudson Bay&lt;/a&gt; have been proposed as the oldest in the world. My question is not related to rocks, but rather to sediment while still forming sedimentary deposits but before lithification (rock formation). While it might be difficult to put a clear limit between &quot;sediments&quot;,&quot;lithified sediments&quot; and &quot;sedimentary rock&quot;, the question is what is the oldest sedimentary deposit on Earth still under sedimentary processes?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2014-12-22T16:55:00.233" LastActivityDate="2020-10-12T09:23:41.390" Title="What is the oldest sediment?" Tags="|sedimentology|rocks|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="3116" PostTypeId="2" ParentId="3115" CreationDate="2014-12-22T16:11:58.427" Score="10" Body="&lt;p&gt;According to page 86 of &lt;a href=&quot;http://highered.mheducation.com/sites/dl/free/0073016543/398471/chamberlin1e_samplechapter.pdf&quot;&gt;Exploring the World Ocean&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In December 1989, ODP scientists drilled Hole 801C&#xA;  and recovered Jurassic-age rocks and sediments, about&#xA;  170–165 million years old, from the Pigafetta Basin in&#xA;  the western Pacific, near the Mariana Islands. Sediments&#xA;  of nearly identical age had been found previously from&#xA;  the Deep Sea Drilling Project Hole 534A, located on the&#xA;  Blake-Bahama basin in the central Atlantic. These sediments&#xA;  and the rocks on which they rest are among the&#xA;  oldest oceanic crust found in the world ocean.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There is a more-detailed discussion at &lt;a href=&quot;http://www-odp.tamu.edu/publications/185_IR/chap_03/chap_03.htm&quot;&gt;Site 801: Sedimentology and Biostratigraphy&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2014-12-22T19:38:12.470" LastActivityDate="2014-12-22T19:38:12.470" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3117" PostTypeId="2" ParentId="377" CreationDate="2014-12-22T17:19:49.120" Score="1" Body="&lt;p&gt;As explained on slide 9 of &lt;a href=&quot;http://faculty.washington.edu/kessler/TALKS/ENSO-AMSteachers2.pdf&quot; rel=&quot;nofollow&quot;&gt;Dr. William S. Kessler's talk&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The warm water pool in the western (Asian) pacific drains eastward and toward the poles. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This causes the thermocline in the western pacific to get closer to the surface, which in turn cools the surface temperature in the western pacific, ending the El Niño.  &lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="111" LastEditDate="2014-12-23T03:16:39.177" LastActivityDate="2014-12-23T03:16:39.177" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="3118" PostTypeId="2" ParentId="377" CreationDate="2014-12-22T20:20:35.813" Score="6" Body="&lt;p&gt;I think it is important to think of the El Niño as just one of the components of a large scale global atmospheric-oceanic phenomenon known as the El Niño and the Southern Oscillation (ENSO). ENSO takes shape as fluctuations of the rainfall, wind, ocean currents and waves. They are by nature very irregular.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Southern Oscillation (SO) was first discovered by Sir Gilbert Walker who conducted seasonal averages for pressure and rainfall at a number of stations around the world. He found that a single spatial pattern was dominant where regions of high pressure in the central South Pacific Ocean and low pressure near Australia and India reverse and the highs turn into lows and the lows into highs. The SO is an atmospheric phenomenon, on the other hand, the El Niño is an oceanic process. Nonetheless, the interconnectedness between both phenomena is significant such that they cannot be considered alone, as pointed out by Bjerknes (1966). The combined action of ENSO is known to cause drought in Australia and the reduction of upwelling in the western coast of South America (which has disastrous consequences for nutrient delivery).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is general agreement that one of the necessary ingredients for the initiation of the ENSO event is the reversal of the general equatorial Trade Wind pattern, an easterly steady wind due to a Walker cell. Westerly wind bursts spanning thousands of kilometers and acting over days or perhaps weeks at a time set off internal waves that transport energy westward and eventually poleward along the western coast of South America, some of that energy bounces off and radiates back east. See sketch below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/PK9Hl.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The equatorial isopycnal depression moves eastward along the equator as a Kelvin wave until reaching the western coast of South America relatively unchanged. These are shallow water waves so the speed is just $c = \sqrt{g'D}$ where $D$ is the depth and $g'$ is the reduced gravity, so they travel at about $c = 2.5$m/s plus 10-20% because they are literally advected by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cromwell_Current&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cromwell Undercurrent&lt;/a&gt;. They transport large amounts of energy over vast distances, depositing it far away from the generation zone in the western Pacific Ocean. Namely, after arrival on the east Pacific coast the equatorial Kelvin wave energy degenerates into two coastal Kelvin waves propagating poleward, and into new diffuse &lt;a href=&quot;https://earthscience.stackexchange.com/questions/12/how-do-rossby-waves-in-the-ocean-form/521#521&quot;&gt;equatorial Rossby waves&lt;/a&gt; radiating towards the west Pacific. It is this removal of energy from the Western pacific through the development of these complicated wave motions and other more subtle processes that eventually brings an ENSO event to an end (chicken and egg?). Because the energy is removed, the SST drops, the trade winds resume thus ending ENSO.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I like the quote from the link in @DavePhD's answer:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;An El Niño event contains the seeds of its own demise.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regional Oceanography: An Introduction By Matthias Tomczak&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-12-22T20:28:52.913" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3120" PostTypeId="1" CreationDate="2014-12-23T05:18:50.543" Score="9" ViewCount="1748" Body="&lt;p&gt;Recently, I realized a lot of factors must contribute toward making a planet habitable, other than just the ones that come to mind like having oxygen, the right temperature, and so on. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What makes a planet habitable? Is there an official set of criteria? I don't see how one could say we have $x$ number of official potentially habitable exoplanets unless there was a standard set of criteria.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: &#xA;I'm not sure if the correct term is &quot;habitable&quot; or &quot;inhabitable&quot;, but what I am obviously asking is what factors determine whether humans and other organisms could live on a given planet.  &lt;/p&gt;&#xA;" OwnerUserId="1260" LastEditorUserId="1260" LastEditDate="2014-12-29T21:25:07.687" LastActivityDate="2016-02-20T00:40:33.610" Title="What are the criteria that make a planet (in)habitable?" Tags="|planetary-science|earth-system|" AnswerCount="3" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="3121" PostTypeId="1" AcceptedAnswerId="3123" CreationDate="2014-12-23T06:46:24.900" Score="10" ViewCount="991" Body="&lt;p&gt;Salar de Uyuni in Bolivia holds a large percentage of the world's lithium reserves. Since the lithium is dissolved as LiCl in the brine, it makes extraction much easier than the alternative: Li bearing minerals in granitic pegmatites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the source of lithium in the brine? Where does it come from?&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-01-03T17:35:38.367" Title="Where does the lithium in Salar de Uyuni comes from?" Tags="|economic-geology|salinity|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3122" PostTypeId="1" AcceptedAnswerId="3124" CreationDate="2014-12-23T07:07:17.213" Score="15" ViewCount="953" Body="&lt;p&gt;Occasionally there are news about a major ore deposit for a specific commodity being found. Some of these recent discoveries are underground, and the &quot;geophysics&quot; aspect of their exploration is more important than the &quot;geology&quot; aspect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This makes me wonder—are there any such known ore deposits that have been found under cities? Some examples might be &quot;the largest gold deposit ever, under Buckingham Palace&quot; or &quot;diamond bearing kimberlite pipe under Central Park in New York&quot;.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="6129" LastEditDate="2021-03-26T16:38:12.873" LastActivityDate="2022-12-04T09:35:34.107" Title="Are there known ore deposits under cities?" Tags="|economic-geology|geography|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="3123" PostTypeId="2" ParentId="3121" CreationDate="2014-12-23T08:43:32.123" Score="9" Body="&lt;p&gt;Due to its increasing economic importance, Lithium deposits are coming under more intense scrutiny, by organisations such as the United States Geological Survey (&lt;a href=&quot;http://alaska.usgs.gov/staff/geology/bradley/pubs/2013_Bradley_prelim_Li_brine_model_OF13-1006.pdf&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt;).  The Salar de Uyuni deposit in Bolivia is one of the deposits of lithium brine that is undergoing modelling and research.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The USGS noted that all lithium brine deposits have some very similar characteristics, climatically, they are in arid environments, be near one or more aquifers and have had sufficient time for the accumulation of the lithium from weathering processes, other commonalities include the tectonic settings, associated volcanic/hydrothermal activity and local petrology (lithium bearing rocks) (&lt;a href=&quot;http://alaska.usgs.gov/staff/geology/bradley/pubs/2013_Bradley_prelim_Li_brine_model_OF13-1006.pdf&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The geological setting of the Salar de Uyuni is described by the USGS (&lt;a href=&quot;http://alaska.usgs.gov/staff/geology/bradley/pubs/2013_Bradley_prelim_Li_brine_model_OF13-1006.pdf&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt;) as being situated in the Altiplano of Bolivia and Chile - a high, internally drained plateau along the crest of the Andean convergent boundary orogen, that includes closed basins. Active faulting is present, causing in subsidence, allowing sediments to accumulate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Observations made by Hofstra et al. (2013) (&lt;a href=&quot;http://econgeol.geoscienceworld.org/content/108/7/1691.abstract&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;) in similar lithium brine deposits in the United States came to the conclusion that melt inclusions in quartz phenocrysts in rhyolite tuffs in association with hydrothermal deposits of tin, molybdenum and beryllium have been found to be heavily enriched in lithium (to the order of 1000's ppm).  Hofstra et al. (2013) surmise from these observations that the source of the lithium has been leached out over time from the nearby rhyolitic tuffs of the Bolivian tin belts to the east of the Salar de Uyuni (&lt;a href=&quot;http://econgeol.geoscienceworld.org/content/108/7/1691.abstract&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;),(&lt;a href=&quot;http://www.osvaldoarce.com/Metallogeny.html&quot; rel=&quot;nofollow&quot;&gt;3&lt;/a&gt;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The lithium is then leached out of the rhyolite by meteoric water, draining into the basins and concentrated by evaporation in the local arid environments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://alaska.usgs.gov/staff/geology/bradley/pubs/2013_Bradley_prelim_Li_brine_model_OF13-1006.pdf&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt;) Bradley et al. 2013, &lt;a href=&quot;http://alaska.usgs.gov/staff/geology/bradley/pubs/2013_Bradley_prelim_Li_brine_model_OF13-1006.pdf&quot; rel=&quot;nofollow&quot;&gt;A Preliminary Deposit Model for Lithium Brines&lt;/a&gt;, &lt;em&gt;USGS Open-File Report 2013–1006&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://econgeol.geoscienceworld.org/content/108/7/1691.abstract&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;) Hofstra et al. 2013, &lt;a href=&quot;http://econgeol.geoscienceworld.org/content/108/7/1691.abstract&quot; rel=&quot;nofollow&quot;&gt;Silicate Melt Inclusion Evidence for Extreme Pre-eruptive Enrichment and Post-eruptive Depletion of Lithium in Silicic Volcanic Rocks of the Western United States: Implications for the Origin of Lithium-Rich Brines*&lt;/a&gt;, &lt;em&gt;Economic Geology&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.osvaldoarce.com/Metallogeny.html&quot; rel=&quot;nofollow&quot;&gt;3&lt;/a&gt;) Arce-Burgoa and Goldfarb, 2009, &lt;a href=&quot;http://www.osvaldoarce.com/Metallogeny.html&quot; rel=&quot;nofollow&quot;&gt;Metallogeny of Bolivia&lt;/a&gt;, &lt;em&gt;Metalliferous Ore Deposits of Bolivia&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-01-03T17:35:38.367" LastActivityDate="2015-01-03T17:35:38.367" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3124" PostTypeId="2" ParentId="3122" CreationDate="2014-12-23T08:44:08.467" Score="17" Body="&lt;p&gt;One example of an ore deposit that runs under a city is the banded iron formation ore in &lt;a href=&quot;http://www.kiruna.se/English/&quot;&gt;Kiruna&lt;/a&gt;. In this case the ore has been mined outside of the city since the turn of the previous century. The ore has been found to run under the city and there are now plans to move the city &lt;a href=&quot;http://www.kiruna.se/Stadsomvandling/City-in-transformation/&quot;&gt;more detailed information&lt;/a&gt;. This has led to a process where the city has to be re-established in a different location including moving a large number of historically significant buildings. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A similar situation is also present in Malmberget (about 120 km S of Kiruna), part of the twin town of Gällivare-Malmberget. In this case the plan is to have Malmberget inhabitants to move to Gällivare. The mining activities at Malmberget have resulted in several collapse features &lt;a href=&quot;https://www.google.se/search?q=malmberget&amp;amp;tbm=isch&amp;amp;tbo=u&amp;amp;source=univ&amp;amp;sa=X&amp;amp;ei=ECmZVNS2LKWmygPonYGQCw&amp;amp;ved=0CDAQsAQ&amp;amp;biw=1211&amp;amp;bih=833&quot;&gt;see images on this link&lt;/a&gt;. There is also some information in English on the &lt;a href=&quot;http://www.gallivare.se/sv/Nya-gallivare/Samhallsomvandling/&quot;&gt;Gällivare web-site&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In both cases there are significant restructuring of the societies. It is also worth noting that the definition of ore is economical which means that what is worth mining depends on market prices. In the case of Iron the market has been strong but has fluctuated significantly. The result is that the planning and decisions for a move such as these  are difficult since they are costly and depend on the market to be financially viable (it is the mining company that largely pays for the move).&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2014-12-23T08:44:08.467" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3126" PostTypeId="2" ParentId="345" CreationDate="2014-12-23T22:24:12.397" Score="7" Body="&lt;p&gt;The reason why amethyst loses its colour in sunlight is due in no small part to what impurity in the $\ce{SiO2}$ crystal structure gives the vivid purple and violet tones of amethyst.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to several sources (&lt;a href=&quot;http://www.mindat.org/min-198.html&quot;&gt;1&lt;/a&gt;),(&lt;a href=&quot;http://link.springer.com/chapter/10.1007%2F978-1-4020-2852-6_63&quot;&gt;2&lt;/a&gt;),(&lt;a href=&quot;http://www.tandfonline.com/doi/abs/10.1080/10420150.2011.553283#.VJniTWcCA&quot;&gt;3&lt;/a&gt;), the main source of the colour is naturally irradation-borne tetravalent iron $\ce{Fe^{4+}}$, which is formed via naturally occurring gamma radiation altering trivalent iron $\ce{Fe^{3+}}$ during crystalisation (&lt;a href=&quot;http://www.tandfonline.com/doi/abs/10.1080/10420150.2011.553283#.VJniTWcCA&quot;&gt;3&lt;/a&gt;).  Other elements exist as impurities but are far less important considerations for the colour produced (&lt;a href=&quot;http://www.tandfonline.com/doi/abs/10.1080/10420150.2011.553283#.VJniTWcCA&quot;&gt;3&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The tetravalent state of iron is inherently unstable in 'normal' surface conditions and the process is reversible due to prolonged exposure to natural sunlight (&lt;a href=&quot;http://www.tandfonline.com/doi/abs/10.1080/10420150.2011.553283#.VJniTWcCA&quot;&gt;3&lt;/a&gt;).  Some research and experiments have demonstrated that some of the bleaching is caused by the UV portion of sunlight (&lt;a href=&quot;http://yadda.icm.edu.pl/yadda/element/bwmeta1.element.elsevier-5f6441a0-f3bc-3552-908b-e86ab30abd5d&quot;&gt;4&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.mindat.org/min-198.html&quot;&gt;1&lt;/a&gt;) &lt;a href=&quot;http://www.mindat.org/min-198.html&quot;&gt;Amethyst&lt;/a&gt;, &lt;em&gt;Mindat.org&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://link.springer.com/chapter/10.1007%2F978-1-4020-2852-6_63&quot;&gt;2&lt;/a&gt;) Dudushenko et al. 2003, &lt;a href=&quot;http://link.springer.com/chapter/10.1007%2F978-1-4020-2852-6_63&quot;&gt;What Oxidation State of Iron Determines the Amethyst Colour?&lt;/a&gt;, &lt;em&gt;ICAME 2003&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.tandfonline.com/doi/abs/10.1080/10420150.2011.553283#.VJniTWcCA&quot;&gt;3&lt;/a&gt;) Hatipoğlu et al. 2011, &lt;a href=&quot;http://www.tandfonline.com/doi/abs/10.1080/10420150.2011.553283#.VJniTWcCA&quot;&gt;Spectral, electron microscopic and chemical investigations of gamma-induced purple color zonings in amethyst crystals from the Dursunbey-Balıkesir region of Turkey&lt;/a&gt;, &lt;em&gt;Radiation Effects and Defects in Solids: Incorporating Plasma Science and Plasma Technology&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://yadda.icm.edu.pl/yadda/element/bwmeta1.element.elsevier-5f6441a0-f3bc-3552-908b-e86ab30abd5d&quot;&gt;4&lt;/a&gt;) Nunes et al. 2013, &lt;a href=&quot;http://yadda.icm.edu.pl/yadda/element/bwmeta1.element.elsevier-5f6441a0-f3bc-3552-908b-e86ab30abd5d&quot;&gt;Spectroscopic study of natural quartz samples&lt;/a&gt;, &lt;em&gt;Radiation Physics and Chemistry&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-12-23T22:24:12.397" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3127" PostTypeId="1" CreationDate="2014-12-23T23:19:05.203" Score="12" ViewCount="848" Body="&lt;p&gt;In particular, does the pull of the moon affect the amount of water vapour in the Earth's atmosphere? In other words, if the moon were larger, or orbiting more closely to the earth, would the increased gravity cause the composition of the atmosphere to change?&lt;/p&gt;&#xA;" OwnerUserId="1369" LastEditorUserId="56" LastEditDate="2015-01-27T05:26:17.107" LastActivityDate="2016-06-17T03:17:05.560" Title="Does the gravitational pull of the moon affect the composition of Earth's atmosphere?" Tags="|atmosphere|moon|water-vapour|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3129" PostTypeId="2" ParentId="2253" CreationDate="2014-12-24T06:42:35.667" Score="7" Body="&lt;p&gt;Implicit and explicit methods have the same differences no matter what context. The building blocks from which these methods are constructed are the same, they all use Taylor series expansion of a function. Of course, there are many different numerical methods, explicit and implicit, with different degrees of &lt;a href=&quot;http://web.stanford.edu/class/cme306/Discussion/Discussion1.pdf&quot; rel=&quot;noreferrer&quot;&gt;numerical accuracy, consistency and stability&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The choice of using implicit or explicit methods is really dependent on the scales involved, the type of accuracy desired, etc. But practically speaking, the most important factor is computational cost. Although implicit methods are unconditionally stable, they are very costly compared to explicit methods. To try to address some of those issues, a lot of atmospheric and oceanic solvers employ hybrid methods. These are called semi-implicit methods where some terms are implicit and others are explicit in order to reduce the computer time required to solve the equations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Essentially, if time accuracy is important, explicit methods are more accurate and less computationally expensive. On the other hand, if the goal is forecasting to a reasonable degree of accuracy then an implicit method is best because, even though it is computationally expensive, one can use very large time steps and get to the answer quickly.&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2014-12-24T08:27:07.157" LastActivityDate="2014-12-24T08:27:07.157" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3130" PostTypeId="1" AcceptedAnswerId="3135" CreationDate="2014-12-24T06:54:35.837" Score="10" ViewCount="327" Body="&lt;p&gt;Does all the car pollution (from about 150 million cars at least in the U.S. and a lot more in all of North America and the rest of the world) all the smoke-stack pollution of various factories and all the Airline pollution running day after day have a deleterious and damaging effect on the general atmosphere and, over time, the climate?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given all the observed pollution that China has caused itself and some of the resulting weird weather events there this certainly seems to be evidence of the damaging effects of car and factory pollution. Has anyone calculated how much exhaust from cars is produced in one day on average in a 'moderate' sized city?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course it seems with all the increased oil production in the U.S. and elsewhere we, human beings are going to keep are love-affair with gas-powered cars for the next 200 or 300 years. That is if we don't use up all the oil and gas in the ground before then.&lt;/p&gt;&#xA;" OwnerUserId="1371" LastEditorUserId="725" LastEditDate="2014-12-24T07:11:14.723" LastActivityDate="2014-12-28T07:27:19.693" Title="Regarding various types of atmospheric pollution" Tags="|meteorology|climate-change|gas|pollution|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="3131" PostTypeId="1" CreationDate="2014-12-24T08:13:18.953" Score="9" ViewCount="227" Body="&lt;p&gt;I am reading this paper, and the authors have an interesting affiliation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/cDKAu.png&quot; alt=&quot;geoalchemy&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Center for Geoalchemy, MIT? A quick Google Scholar search shows that it was a thing in the late 1970s to 1980s. Seems like they were researching geochemical petrology. Any ideas for the source/reason for this name?&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="56" LastEditDate="2015-01-08T06:21:32.640" LastActivityDate="2015-01-08T06:21:32.640" Title="What is Geoalchemy?" Tags="|terminology|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="3132" PostTypeId="1" CreationDate="2014-12-24T10:47:41.330" Score="11" ViewCount="2704" Body="&lt;p&gt;I'm trying to learn how to make sense of numbers in a forecast. I can interpret temperature and wind speed, but I don't know what to make of rainfall. What does it mean, for a human, that there will be (for example) 0.5mm precipitation? Is it a lot or not? Is there a reference online describing precipitation amounts in everyday terms? I've been looking for something like that, but found nothing, only formal definitions of measurement.&lt;/p&gt;&#xA;" OwnerUserId="1372" LastActivityDate="2015-01-01T08:12:24.583" Title="Intuitive explanation of precipitation amount" Tags="|meteorology|measurements|precipitation|weather-forecasting|" AnswerCount="0" CommentCount="0" FavoriteCount="0" ClosedDate="2021-07-20T05:15:37.117" ContentLicense="CC BY-SA 3.0" />
  <row Id="3133" PostTypeId="2" ParentId="2253" CreationDate="2014-12-24T17:37:08.013" Score="2" Body="&lt;p&gt;Here are some excerpts from my answer &lt;a href=&quot;https://scicomp.stackexchange.com/questions/7628/what-is-the-difference-between-implicit-fem-and-explicit-fem&quot;&gt;here&lt;/a&gt; at scicomp ...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;You have to solve a linear system of the type Ax=b in the implicit scheme where as in the explicit scheme you do not,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your time step in the explicit scheme is limited by the CFL criteria for stability. Implicit schemes are unconditionally stable (though in practice you still need a reasonable time step for accurary)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Typically problems where inertial effects are important are solved by explicit schemes where as quasi-static problems usually use an implicit scheme. However there are exceptions.&quot;&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="-1" LastEditDate="2017-04-13T12:53:55.997" LastActivityDate="2014-12-24T17:37:08.013" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3134" PostTypeId="2" ParentId="2253" CreationDate="2014-12-24T17:38:53.257" Score="8" Body="&lt;p&gt;The answer by @IsopycnalOscillation explains some implications of using explicit and implicit schemes and in what applications one is preferred over the other. Here, I describe how these two methods actually work, and how does the implicit scheme uses knowledge of the later state.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take the ordinary differential equation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\dfrac{\partial u}{\partial t} = f(u,t)&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and for simplicity, let $f(u,t) = -cu$, where $c$ is a positive constant and $u = u(t)$. The equation is then:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\dfrac{\partial u}{\partial t} = -cu&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;often called the linear drag equation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Again, for simplicity, we consider the simplest two schemes, a first order forward Euler differencing (explicit), and a first order Euler backward differencing (implicit). As you know, forward Euler differencing yieds:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;u_{n+1}=u_n-c\Delta tu_{n}=u_n(1-c\Delta t)&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This method is called explicit because the future state is evaluated as function of the present state. From the von Neumann stability method where the growth factor is defined as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\lambda = \dfrac{u_{n+1}}{u_n} = 1-c\Delta t,&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;the scheme is stable when $|\lambda|&amp;lt;1$, neutral when $|\lambda|=1$, and unstable when $|\lambda|&amp;gt;1$. We see that the forward Euler method applied to the linear drag equation may be unstable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With the implicit Euler backward differencing, we have:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;u_{n+1}=u_n-c\Delta t u_{n+1}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rearranging the terms leads us to:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;u_{n+1} = \dfrac{u_n}{1+c\Delta t}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Notice that the $u_{n+1}$ is not found on the right-hand side anymore. Here, the growth factor is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\lambda = \dfrac{1}{1+c\Delta t}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We see that, in this case, $|\lambda|&amp;lt;1$ holds for any value of $c$ and $\Delta t$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, if one is concerned about stability, an implicit method is advantageous for solving this equation. However, notice that the implicit method is more computationally heavy, even in this simple case, because a division is significantly more expensive operation than multiplication. This is especially true in larger and more complex systems of equations where $f(u,t)$ may be a large matrix that need to be inverted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good introductory text on these methods and there applications in atmosphere and ocean modeling can be found here: &lt;a href=&quot;http://twister.caps.ou.edu/CFD2013/Mesinger_ArakawaGARP.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mesinger and Arakawa: Numerical Methods Used in Atmospheric Models (1976)&lt;/a&gt;. For more references, see the answer to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2806/resources-for-learning-the-technical-parts-of-atmospheric-modeling/2807&quot;&gt;this question&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-12-24T17:49:47.783" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3135" PostTypeId="2" ParentId="3130" CreationDate="2014-12-24T20:33:00.353" Score="6" Body="&lt;p&gt;As a USA resident, the EPA is the best place to start when wondering about the emissions inventory of atmospheric pollutants or pollutant precursors that affect the National Ambient Air Quality Standards (e.g. Particulate Matter, Carbon Monoxide, Sulfur Dioxide, Lead, Nitrogen Oxides, Volatile Organic Compounds).  The EPA compiles a comprehensive emissions inventory of all criteria pollutants at the county level which is available in the National Emissions Inventory (compiled once every 3 years).  You can see the summary of your county at &lt;a href=&quot;http://www.epa.gov/air/emissions/where.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.epa.gov/air/emissions/where.htm&lt;/a&gt;.  As for the effects of atmospheric pollution, it is important to consider the lifetime of said pollutants in the atmosphere in order to put their environmental impacts into perspective.  For instance, the air pollutants covered by the National Ambient Air Quality Standards have immediate health effects when high concentrations are breathed in regularly.  Both animals and plants are adversely affected by these irritating and sometimes toxic chemicals, but these pollutants are also reactive and do not last long in the atmosphere unless they are constantly being replenished (e.g. daily traffic).  Air quality also impacts critical nitrogen loads on ecosystems and possible production of acid rain.&lt;/p&gt;&#xA;&lt;p&gt;If you are interested in Greenhouse Gases (e.g. methane, carbon dioxide, CFCs, nitrous oxide), the EPA has a separate site for those emissions since they are not part of the same regulatory framework  &lt;a href=&quot;http://www.epa.gov/climatechange/ghgemissions/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.epa.gov/climatechange/ghgemissions/&lt;/a&gt; .  Greenhouse gases typically do not cause adverse health effects for plants or animals on land.  However, they have long-term radiative effects (e.g. the greenhouse effect) because they stay in the atmosphere for many years and trap infrared light.  These long-term radiative effects are what can change climate and consequently land cover.  Furthermore, most of the excess carbon is absorbed by the ocean, which creates carbonic acid. Increased acidity of the ocean causes severe problems for marine ecosystems.&lt;/p&gt;&#xA;&lt;p&gt;The EPA states that in 2012 the CO2 equivalent GHG emissions for the USA by sector was:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Electricity production (32% of 2012 greenhouse gas emissions) - Electricity production generates the largest share of greenhouse gas emissions. Over 70% of our electricity comes from burning fossil fuels, mostly coal and natural gas.&lt;/p&gt;&#xA;&lt;p&gt;Transportation (28% of 2012 greenhouse gas emissions) - Greenhouse gas emissions from transportation primarily come from burning fossil fuel for our cars, trucks, ships, trains, and planes. Over 90% of the fuel used for transportation is petroleum based, which includes gasoline and diesel.&lt;/p&gt;&#xA;&lt;p&gt;Industry (20% of 2012 greenhouse gas emissions) - Greenhouse gas emissions from industry primarily come from burning fossil fuels for energy as well as greenhouse gas emissions from certain chemical reactions necessary to produce goods from raw materials.&lt;/p&gt;&#xA;&lt;p&gt;Commercial and Residential (10% of 2012 greenhouse gas emissions) - Greenhouse gas emissions from businesses and homes arise primarily from fossil fuels burned for heat, the use of certain products that contain greenhouse gases, and the handling of waste.&lt;/p&gt;&#xA;&lt;p&gt;Agriculture (10% of 2012 greenhouse gas emissions) - Greenhouse gas emissions from agriculture come from livestock such as cows, agricultural soils, and rice production.&lt;/p&gt;&#xA;&lt;p&gt;Land Use and Forestry (offset of 15% of 2012 greenhouse gas emissions) - Land areas can act as a sink (absorbing CO2 from the atmosphere) or a source of greenhouse gas emissions. In the United States, since 1990, managed forests and other lands have absorbed more CO2 from the atmosphere than they emit.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;If we consider GHGs on a global level (see Global Carbon Project &lt;a href=&quot;http://www.globalcarbonproject.org/carbonbudget/index.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.globalcarbonproject.org/carbonbudget/index.htm&lt;/a&gt; ) we can see how each sector has impacted the atmospheric concentration of CO2 over the past 143 yrs.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/S0OtF.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2014-12-28T07:27:19.693" CommentCount="18" ContentLicense="CC BY-SA 3.0" />
  <row Id="3136" PostTypeId="1" CreationDate="2014-12-25T09:59:51.490" Score="7" ViewCount="125" Body="&lt;p&gt;In a recent study presented in the article &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2014GL060801/full&quot;&gt;First global observations of the mesospheric potassium layer&lt;/a&gt; (Dawkins et al. 2014), space-borne resonance fluorescence observations confirmed previous LIDAR observations of a semi-annual variability of mesospheric meteoric $\ce{K}$, which is very different from the annual (seasonal) pattern observed for other metals such as $\ce{Na}$ and $\ce{Fe}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What causes the semi-annual mesospheric meteoric potassium variability?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-03-28T11:09:09.857" LastActivityDate="2015-03-29T06:46:34.170" Title="What causes the semi-annual mesospheric meteoric potassium variability?" Tags="|atmosphere|upper-atmosphere|atmosphere-modelling|atmospheric-chemistry|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3137" PostTypeId="1" AcceptedAnswerId="3156" CreationDate="2014-12-25T12:01:08.987" Score="7" ViewCount="874" Body="&lt;p&gt;We have several perennial rivers in my country that originate out of high altitude alpine glacier melt. I can understand snow or glacier melting in the summer to increase the flows but it is observed that flows do not come to a  complete halt during peak winter as well even though temperatures maybe below freezing point. Upon investigation it was revealed that a process called calving(presumably pressure differences)  is responsible for glacier breakdown but wikipedia claims that the mathematics of this process is still in development. &#xA;Is it possible to get an expert answer on this phenomenon ? &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastActivityDate="2014-12-29T12:17:44.480" Title="How do perennial rivers in high alpine areas maintain year round flows?" Tags="|hydrology|glaciology|" AnswerCount="2" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3138" PostTypeId="1" CreationDate="2014-12-25T16:27:26.460" Score="6" ViewCount="159" Body="&lt;p&gt;Taking &lt;a href=&quot;http://en.wikipedia.org/wiki/Fresh_water&quot; rel=&quot;nofollow&quot;&gt;freshwater&lt;/a&gt; as being: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, icebergs, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;How much has the total available freshwater change over time? How much has it gone from one reservoir to another? How can we estimate future changes?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="192" LastEditDate="2014-12-25T22:20:44.827" LastActivityDate="2014-12-25T22:20:44.827" Title="Freshwater changes in time?" Tags="|hydrology|water|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="3140" PostTypeId="1" CreationDate="2014-12-26T01:39:11.863" Score="14" ViewCount="848" Body="&lt;p&gt;According to the United States Geological Survey Report (USGS) &lt;a href=&quot;http://pubs.usgs.gov/sir/2013/5079/SIR2013-5079.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Groundwater Depletion in the United States (1900–2008)&lt;/a&gt;, the Ogallala Aquifer (or High Plains Aquifer) is a vital source of groundwater for a major agricultural region in the United States. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the USGS report, there is evidence of significant and ongoing depletion of the aquifer.  From the USGS report, the total depletion at the end of 2008 is about 341 km$^3$ and the rate of depletion at the time of writing the report was &quot;continuing as high a rate as ever&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Wchkh.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Ogallala Aquifer is labelled as number 13, in the above &lt;a href=&quot;http://water.usgs.gov/edu/gwdepletion.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS map&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given the effects of climate change on aquifer recharge and drought cycles, coupled with the human depletion of the aquifer, &lt;strong&gt;is there any evidence that 'peak-water' could occur in the Ogallala Aquifer?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;By 'peak-water', I am referring to a point where it becomes practically and economically impossible to pump water from the aquifer&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;This question is related to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/723/recharge-a-dry-aquifer&quot;&gt;Recharge a dry aquifer?&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-05-06T15:02:37.910" Title="'Peak water' in the Ogallala Aquifer, USA?" Tags="|hydrology|human-influence|groundwater|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3141" PostTypeId="5" CreationDate="2014-12-26T18:16:14.373" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2014-12-26T18:16:14.373" LastActivityDate="2014-12-26T18:16:14.373" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3142" PostTypeId="4" CreationDate="2014-12-26T18:16:14.373" Score="0" Body="In meteorology, a cloud refers to a visible group of liquid droplets and/or frozen crystals made of water or various chemicals, suspended in the atmosphere." OwnerUserId="192" LastEditorUserId="192" LastEditDate="2014-12-26T20:30:13.113" LastActivityDate="2014-12-26T20:30:13.113" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3143" PostTypeId="2" ParentId="2173" CreationDate="2014-12-26T18:59:17.413" Score="8" Body="&lt;p&gt;For Earth, Titan and Venus, I think there are continuing processes that are providing $\ce{N2}$ to the atmosphere of these planets.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Concerning the Earth, there is the well documented &lt;a href=&quot;https://en.wikipedia.org/wiki/Nitrogen_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nitrogen cycle&lt;/a&gt; based on flora.  There are also other significant sources for nitrogen from inorganic processes.  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Deep crust/mantle core sources for nitrogen: &lt;a href=&quot;http://meetingorganizer.copernicus.org/EMC2012/EMC2012-198.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nitrogen solubility in mantle minerals&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Volcanic eruptions : &lt;a href=&quot;https://en.wikipedia.org/wiki/Volcanic_gas&quot; rel=&quot;nofollow noreferrer&quot;&gt;Volcanic gas&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;Metamorphic processes : &lt;a href=&quot;http://dx.doi.org/10.1016/j.epsl.2014.06.029&quot; rel=&quot;nofollow noreferrer&quot;&gt;Anomalous nitrogen isotopes in ultra high-pressure metamorphic rocks from the Sulu orogenic belt: Effect of abiotic nitrogen reduction during fluid–rock interaction&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Assuming the rock processes on Earth are also occurring on Titan and Venus, similar inorganic processes may be occurring on other worlds. I think it is a good educated guess even though we really have very very little hard evidence of rock processes other planets.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for Mars, its thin atmosphere may indicate that is cannot hold onto $\ce{N2}$ and there may be very little $\ce{N2}$ currently being created on Mars.  &lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="2470" LastEditDate="2016-11-27T06:26:28.783" LastActivityDate="2016-11-27T06:26:28.783" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="3145" PostTypeId="2" ParentId="3115" CreationDate="2014-12-27T09:55:15.897" Score="1" Body="&lt;p&gt;The question is a bit confusing: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If (as suggested by the body of the question) you are interested in unlithified sediment only, then the transition from unlithified to lithified can be found at the bottom of most seas, lakes, and continental basins, but the factors determining the age or depth at which they became lithified rock are many, including the temperature/pressure/chemical conditions of the matrix. So far there is no way to determine the oldest unlithified sediment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If (as suggested by the title of the question) you were not so interested in the lithified/unlithified bit, and assuming that by 'still under sedimentary processes' you refer to a place where sedimentation is still ongoing, then you are looking for the place on Earth where sedimentation has been active for the longest period down to the present. I believe we would call this 'the oldest active sedimentary basin' (with 'active' used in geology as 'presently accumulating sediment'). In such case, then the answer by DavePhD points to sediment deposited on the oldest subducting oceanic plate, I guess because oceanic environments should undergo nearly perennial sedimentation. But note that most of the sediment in that drilling is actually lithified, it became solid rock because it spent many million years at large pressures. Furthermore, the western Pacific is not the oldest oceanic plate on Earth. In the Eastern Mediterranean there are documented remains of the Tethys Ocean dating at 270 Myr. Sedimentation should have been uninterrupted ever since that plate formed. I have no idea if those sediments have ever been drilled. &lt;/p&gt;&#xA;" OwnerUserId="1379" LastEditorUserId="1379" LastEditDate="2016-01-31T10:03:10.940" LastActivityDate="2016-01-31T10:03:10.940" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3146" PostTypeId="2" ParentId="3100" CreationDate="2014-12-27T14:06:53.347" Score="14" Body="&lt;p&gt;The tectonic history of Australia's Great Dividing Range is very complex, extending back into the Neoproterozoic era (&lt;a href=&quot;http://sp.lyellcollection.org/content/318/1/1.full&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;), and is &lt;em&gt;far&lt;/em&gt; more complex than the Wikipedia quote. Additionally, evidence (shown in this answer) demonstrated that the eastern third of the Australian landmass is comprised of accreted arc systems that developed along the continental-oceanic Eastern Gondwana boundary following the initiation of subduction in the late Neoproterozoic (&lt;a href=&quot;http://sp.lyellcollection.org/content/318/1/1.full&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;) forming in a series orogenies (as shown on the map below (&lt;a href=&quot;http://www.mdpi.com/2076-3263/3/3/354/htm&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;) - not due to a single continental collision. These orogenies are incorporated in the 'Terra Australis' Orogen that ceased approximately 230 million years ago (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0012825204001011&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/7opPH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As can be seen by the diagram below (&lt;a href=&quot;http://www.mdpi.com/2076-3263/3/3/354/htm&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;), the youngest accreted orogen occurs in the eastern most margins of the Australian landmass, where the Great Dividing Range is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/pG2KF.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, the cessation of arc accretion, did not end the tectonic story affecting the Great Dividing Range.  Large Igneous Province volcanics occurred in north Queensland in the early Cretaceous, then epeirogenic uplift, exhumation and continental rupturing culminating in the opening of the Tasman Basin occurred in the mid Cretaceous, leading to the separation of Zealandia (New Zealand + submerged continental shelf) and giving shape to the eastern Australian coastline (and eastern boundary of much of the Great Dividing Range) (&lt;a href=&quot;http://eprints.qut.edu.au/58545/1/paper-11_proofs.pdf&quot; rel=&quot;noreferrer&quot;&gt;4&lt;/a&gt;).  The rifting process is illustrated below&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/yfBDj.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image source: &lt;a href=&quot;http://www.geomaps.com.au/scripts/australianalps.php&quot; rel=&quot;noreferrer&quot;&gt;Formation of The Australian Alps&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://sp.lyellcollection.org/content/318/1/1.full&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;) Cawood et al. 2009 &lt;a href=&quot;http://sp.lyellcollection.org/content/318/1/1.full&quot; rel=&quot;noreferrer&quot;&gt;Accretionary orogens through Earth history&lt;/a&gt;, &lt;em&gt;The Geological Society&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.mdpi.com/2076-3263/3/3/354/htm&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;) Foster and Goscombe, 2013 &lt;a href=&quot;http://www.mdpi.com/2076-3263/3/3/354/htm&quot; rel=&quot;noreferrer&quot;&gt;Continental Growth and Recycling in Convergent Orogens with Large Turbidite Fans on Oceanic Crust&lt;/a&gt;, &lt;em&gt;Geosciences&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0012825204001011&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;) Cawood, 2005, &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0012825204001011&quot; rel=&quot;noreferrer&quot;&gt;Terra Australis Orogen: Rodinia breakup and development of the Pacific and Iapetus margins of Gondwana during the Neoproterozoic and Paleozoic&lt;/a&gt;, &lt;em&gt;Earth-Science Reviews&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://eprints.qut.edu.au/58545/1/paper-11_proofs.pdf&quot; rel=&quot;noreferrer&quot;&gt;4&lt;/a&gt;) Bryan et al. 2012, &lt;a href=&quot;http://eprints.qut.edu.au/58545/1/paper-11_proofs.pdf&quot; rel=&quot;noreferrer&quot;&gt;Early-mid Cretaceous tectonic evolution of eastern&#xA;Gondwana: From silicic LIP magmatism to continental rupture&lt;/a&gt;, &lt;em&gt;Episodes&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-12-27T14:06:53.347" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3147" PostTypeId="1" CreationDate="2014-12-27T22:18:36.483" Score="7" ViewCount="321" Body="&lt;p&gt;Is there a consensus on when the Persian Gulf reached its modern day levels? So far the material I have read says the Persian Gulf attained its present levels around 4000 BCE, but I am not too sure. Any suggestions? Thanks.&lt;/p&gt;&#xA;" OwnerUserId="1380" LastActivityDate="2014-12-27T23:33:56.633" Title="Extent of the Persian Gulf" Tags="|geology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3148" PostTypeId="2" ParentId="3147" CreationDate="2014-12-27T23:33:56.633" Score="5" Body="&lt;p&gt;You are pretty much spot on in terms of the date.  According to the article &lt;a href=&quot;http://people.rses.anu.edu.au/lambeck_k/pdf/171.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Shoreline reconstructions for the Persian Gulf since the last&#xA;glacial maximum&lt;/a&gt; (Lambeck, 1996) based on models of glacio-hydro-isostatic effects of the end of the last ice age and the article &lt;a href=&quot;http://www.psu.edu/dept/liberalarts/sites/kennett/djkennett/pdf/Kennett_Kennett2006.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Early State Formation&#xA;in Southern Mesopotamia:&#xA;Sea Levels, Shorelines,&#xA;and Climate Change&lt;/a&gt; (Kennett and Kennett, 2006) indicate from archaeological observations that at around 6000 years before present (~4000 BCE) that the present shorelines were approximately shaped.  Both articles record an initial inundation of the Tigris-Euphrates delta.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The process is summarised in the image below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/ndpBo.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image source: &lt;a href=&quot;http://emvc.geol.ucsb.edu/2_infopgs/IP2IceAge/ePersGulfFlood.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;University of California - Santa Barabara&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-12-27T23:33:56.633" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3149" PostTypeId="2" ParentId="2173" CreationDate="2014-12-28T05:40:18.853" Score="4" Body="&lt;p&gt;A huge factor affecting a planet's atmospheric composition is the planet's escape velocity. From Wikipedia, we have a &lt;a href=&quot;https://en.wikipedia.org/wiki/Escape_velocity#List_of_escape_velocities&quot; rel=&quot;nofollow&quot;&gt;table of escape velocities&lt;/a&gt;, and here are some sample figures:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Earth: 11.2 km/s&lt;/li&gt;&#xA;&lt;li&gt;Mars: 5.0 km/s&lt;/li&gt;&#xA;&lt;li&gt;Jupiter: 59.6 km/s&lt;/li&gt;&#xA;&lt;li&gt;Pluto: 1.2 km/s&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The molecules of an atmospheric gas all fly around with different velocities. Turns out, these velocities follow the &lt;a href=&quot;https://en.wikipedia.org/wiki/Normal_distribution&quot; rel=&quot;nofollow&quot;&gt;normal distribution&lt;/a&gt;. That is, there is a bell curve with a mean. If the mean velocity of the gas particles is higher than the escape velocity of a given planet, then you probably won't see much of that gas on the planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mars has much less mass than the Earth and so its escape velocity is much lower. If you were to look up the velocity distribution of nitrogen molecules in Mars' atmosphere, you'd probably find that the average velocity is greater than 5.0 km/s.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this is interesting to you, there's so much more! There's an entire field of physics called statistical physics which is the foundation of so many other fields, like chemistry and thermodynamics. Studying these fields allows you develop physical intuition which can be super helpful for reasoning about all the crazy stuff which happens on this planet.&lt;/p&gt;&#xA;" OwnerUserId="1381" LastEditorUserId="1381" LastEditDate="2014-12-28T05:46:10.027" LastActivityDate="2014-12-28T05:46:10.027" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3150" PostTypeId="2" ParentId="3137" CreationDate="2014-12-28T13:27:50.373" Score="4" Body="&lt;p&gt;Not claiming to be an expert, but I think the process you're referring to is called pressure melt. This effect occurs when the pressure at the bottom of the glacier is high enough to either shift the melting point slightly (melting point decreases by 0.7$\,^{\circ}$C per km of ice according to &lt;a href=&quot;http://uregina.ca/~sauchyn/geog323/glacial1.html&quot; rel=&quot;nofollow&quot;&gt;this link&lt;/a&gt;, which provides some more background information on processes and conditions inside glaciers), which combined with frictional energy from the constant movement of the glacier, and, in some regions, geothermal energy causes a constant supply of liquid water. Since these discharges are usually concentrated under the ice (also the principle behind the formation of &lt;a href=&quot;http://en.wikipedia.org/wiki/Esker&quot; rel=&quot;nofollow&quot;&gt;eskers&lt;/a&gt;), leading to large discharges at a few emergence points with enough energy to prevent them from freezing over.&lt;/p&gt;&#xA;" OwnerUserId="79" LastActivityDate="2014-12-28T13:27:50.373" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3151" PostTypeId="1" AcceptedAnswerId="3153" CreationDate="2014-12-28T19:30:42.850" Score="10" ViewCount="149" Body="&lt;p&gt;Was there any experimental study that determined $D$ for apatite and silicate liquid?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The GERM Kd database only &lt;a href=&quot;http://earthref.org/KDD/e:41/?&amp;amp;sort=mineral&quot;&gt;lists one study with carbonatite liquid&lt;/a&gt;, but that's not what I'm looking for.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2014-12-29T03:17:37.633" Title="What's the partition coefficient (D) of Nb for apatite?" Tags="|geochemistry|petrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3152" PostTypeId="2" ParentId="2501" CreationDate="2014-12-29T02:44:41.383" Score="7" Body="&lt;p&gt;This answer will focus on recent research evidence found within the Siberian Traps deposits.  For the purposes of this answer, the theory that a possible Wilkes Land impact resulted in the Siberian traps as an antipode volcanic response will not be included (please see the question and answer to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/3086/can-impact-events-cause-widespread-volcanic-activity-on-the-other-side-of-the-pl&quot;&gt;Can impact events cause widespread volcanic activity on the other side of the planet?&lt;/a&gt; for details of current modelling doubts of this mechanism).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many researchers cite that the initial cause of the Siberian Traps was a mantle plume, some refer to it as a 'superplume' that inpinged into the upper mantle, as shown in the diagram below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/sv8kn.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image source: &lt;a href=&quot;http://palaeos.com/paleozoic/permian/permian4.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Permian Period&lt;/a&gt;, &lt;em&gt;Palaeos&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, according to Sobolev et al. (2011), observations and measurements of the region affected by the Siberian Traps exhibit no evidence of pre-magmatic uplift nor lithospheric stretching that can be associated with mantle plume activity (e.g. the Afar Region in Ethiopia), their models suggest that there was extensive plume erosion of the cratonic crust over a considerable length of time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Petrological evidence by Sobolev et al. (2011) suggest that some recycled oceanic crust existed at the head of the plume. This contamination was noted in $\delta^{34}\ce{S}$ analysis of melt inclusions by Bryan and Ferrari, (2013) and Black et al. (2014), who determined that the mantle melt source was close to that found in mid-ocean ridge basalts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Black et al. (2014) also note that a significant contributor to $\delta^{34}\ce{S}$ (up to 25%) was derived from evaporitic sources. This related to the observations made by Jerram et al. (2013) of the contact metamosphism around the doleritic dykes and sills, indicating that the basaltic magma was injected into an organic and salt rich sedimentary basin.  This interaction between the organics an salt and molten rock would have released halocarbons, $\ce{CO2}$ etc that are attributed to the mass extinction at the time (Jerram et al. 2013; Self et al. 2014).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This, and the prevalence of tuff leads to Jerram et al. (2013) questioning whether the Siberian Traps were the result of widespread explosive volcanic activity, related.  The dyke and sill intrusions are believed to have caused episodic explosive eruptive sequences, according to Self et al. (2014).  Some of these eruptions were phreatomagmatic depositing mafic volcaniclasts according to Bryan and Ferrari, (2013).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As, the crust eroded due to the plume (Sobolev et al. 2011), the eruptive sequences transitioned to basaltic lava flows, these are believed to have also been episodic, according to Self et al. (2014) with pulses of magma production and lava eruptions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The map below shows the distribution of sill intrusions, pyroclasts and lava of the Siberian Traps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/u2CIu.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image source: &lt;a href=&quot;http://www.largeigneousprovinces.org/aug11&quot; rel=&quot;nofollow noreferrer&quot;&gt;IAVCEI&lt;/a&gt; - the red are sill intrusions, the light purple are pyroclasts and the dark purple is lava.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Black et al. 2014, &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0012821X14001484&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sulfur isotopic evidence for sources of volatiles in Siberian Traps magmas&lt;/a&gt;, &lt;em&gt;Earth and Planetary Science Letters&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bryan and Ferrari, 2013, &lt;a href=&quot;http://www.mantleplumes.org/WebDocuments/BryanFerrari2013.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Large igneous provinces and silicic large&#xA;igneous provinces: Progress in our understanding&#xA;over the last 25 years&lt;/a&gt;, &lt;em&gt;Geological Society of America Bulletin&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Jerram et al. 2013, &lt;a href=&quot;http://adsabs.harvard.edu/abs/2013AGUFM.V31F..07J&quot; rel=&quot;nofollow noreferrer&quot;&gt;What happened at the start of the Siberian Traps? Understanding the onset of flood volcanism&lt;/a&gt;, &lt;em&gt;American Geophysical Union, Fall Meeting 2013&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Self et al. 2014, &lt;a href=&quot;http://specialpapers.gsapubs.org/content/early/2014/08/21/2014.2505_16.full.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Emplacement characteristics, time scales, and volcanic gas&#xA;release rates of continental fl ood basalt eruptions on Earth&lt;/a&gt;, &lt;em&gt;The Geological Society of America&#xA;Special Paper 505&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sobolev et al. 2011, &lt;a href=&quot;http://www.nature.com/nature/journal/v477/n7364/abs/nature10385.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Linking mantle plumes, large igneous provinces and environmental catastrophes&lt;/a&gt;, &lt;em&gt;Nature&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-12-30T07:35:19.843" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3153" PostTypeId="2" ParentId="3151" CreationDate="2014-12-29T03:17:37.633" Score="5" Body="&lt;p&gt;Yes, in the paper &lt;a href=&quot;http://www.ierm.ed.ac.uk/homes/sklemme/publications/apatite_GCA_2006.pdf&quot; rel=&quot;noreferrer&quot;&gt;Trace element partitioning between apatite and silicate melts&lt;/a&gt; (Prowatke and Klemme, 2006), where they present experimental apatite/melt trace element partition coefficients for a large number of trace elements, including $\ce{Nb}$.  The experiments were performed at pressures of 1 GPa and at a temperature of 1250 C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What the experiments revealed were:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;An average of $D$ = 0.0018 for $\ce{Nb}$ (this value is an average of &lt;code&gt;Table 5: Trace element partition coefficients between apatite and different silicate melt&lt;/code&gt; of the linked document).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$D_{Nb} \approx D_{Ta}$&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;The partition coefficient was not significantly affected by changing melt compositions.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-12-29T03:17:37.633" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3154" PostTypeId="2" ParentId="3120" CreationDate="2014-12-29T04:53:18.553" Score="1" Body="&lt;p&gt;Typically when searching for possible life on other worlds (aka inhabitable), scientists look for terrestrial worlds with liquid water or some other basic liquid.  If a world has a solvent of some sort and some type of geologic activity (which is a source of heat and molecular diversity), then it would be considered possibly &quot;inhabitable&quot; for the types of life we are familiar with.  However, if a planet has some strange characteristic that would cause periodic extreme events (e.g. highly elliptical orbit), it's environment would be less  stable and therefore less likely to support life.  Check out this site on the subject: &lt;a href=&quot;http://lcogt.net/spacebook/what-are-requirements-life-arise-and-survive&quot; rel=&quot;nofollow&quot;&gt;http://lcogt.net/spacebook/what-are-requirements-life-arise-and-survive&lt;/a&gt; or refer to wikipedia as mentioned in the comments &lt;a href=&quot;http://en.wikipedia.org/wiki/Planetary_habitability&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/Planetary_habitability&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2014-12-29T05:52:39.873" LastActivityDate="2014-12-29T05:52:39.873" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3155" PostTypeId="2" ParentId="3120" CreationDate="2014-12-29T06:53:51.687" Score="1" Body="&lt;p&gt;Few other conditions in addition to liquid water and plate tectonics are global magnetic field and distance of the planet from the host star.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a recent comprehensive review on the subject please refer to this article - &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.geology.wisc.edu/~astrobio/docs/Lammer_et_al_2009_Astron_Astro_Rev.pdf&quot; rel=&quot;nofollow&quot;&gt;http://www.geology.wisc.edu/~astrobio/docs/Lammer_et_al_2009_Astron_Astro_Rev.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastActivityDate="2014-12-29T06:53:51.687" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3156" PostTypeId="2" ParentId="3137" CreationDate="2014-12-29T12:17:44.480" Score="4" Body="&lt;p&gt;Liquid water can be stored in several ways in a glacier and the glacier environment. As ice and snow melts water can be temporarily stored stored in crevasses in the glacier or as equivalent to ground water in the permeable firn and snow pack on the glacier. Such water is slowly released, although sudden releases are also known, during the frozen season. In addition, sediments under and around the glacier also store ground water which is released during the frozen period. Altogether, this is known as &quot;base flow&quot; in hydrology. depending on the size and evacuation rates, the flow can persists throughout a winter season.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are factors that influence this behaviour. The general case described above concerns so-called temperate glaciers. Glaciers at very high elevations and latitudes may be completely below the freezing point. There may also be permafrost in surroundings. Under such circumstances the storage volume can be very small and winter flow may cease altogether after some time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A small fraction of water can also be generated by melting from geothermal heat. If the glacier is temperate at the bed the heat flux will provide energy to generate melt. A simple calculation based on typical continental geothermal heat fluxes show that the energy is sufficient to melt millimetres to a centimetre of basal ice. Consider that this melting occurs during the course for a year and the volume of water will be the melt rate multiplied by the basal ice-ground contact area of the glacier and the numbers will show that the runoff will be minuscule. Hence such contributions are generally not comparable to those produced by the &quot;base flow&quot; from ground and glacier aquifers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following paper provides a thorough description of storage of water in glaciers:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Jansson, P., Hock, R. and Schneider, T., 2003. The concept of glacier storage -- A review. &lt;em&gt;Journal of Hydrology&lt;/em&gt;. 282 (1-4), 116-129.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A large volume of literature on glacier hydrology and runoff can be found in &lt;em&gt;Journal of Glaciology&lt;/em&gt;.&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2014-12-29T12:17:44.480" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3157" PostTypeId="1" AcceptedAnswerId="3158" CreationDate="2014-12-29T16:50:54.740" Score="12" ViewCount="1847" Body="&lt;p&gt;I am trying to understand whether there is one &quot;standard&quot; meaning of the width of represented strata in stratigraphic columns, but I can find nothing online or in my geology books.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I notice that, sometimes, under stratigraphic columns there can be legenda explaining how the width of the represented strata relates to the measure of the clasts of a conglomerate, but I have also found stratigraphic columns with no stratum of conglomerate or breccia where not all the strata are equally large.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the width of strata usually an increasing function of the area occupied by the respective stratum? Can width represent other characteristics of the described stratum?&lt;/p&gt;&#xA;" OwnerUserId="620" LastEditorDisplayName="user889" LastEditDate="2015-01-05T18:40:22.033" LastActivityDate="2015-04-21T08:39:51.227" Title="Width of strata in stratigraphic column" Tags="|geology|measurements|stratigraphy|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="3158" PostTypeId="2" ParentId="3157" CreationDate="2014-12-29T21:17:50.220" Score="14" Body="&lt;p&gt;The width of a unit in a stratigraphic column, or 'log', sometimes represents the average  grainsize of the rock. I can imagine it being keyed to some other property, but grainsize is common. You'll find lots of examples with a quick &lt;a href=&quot;https://www.google.ca/search?q=sedimentary+log&amp;amp;es_sm=91&amp;amp;source=lnms&amp;amp;tbm=isch&quot; rel=&quot;nofollow noreferrer&quot;&gt;search for 'sedimentary log'&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The height of a unit typically represents thickness if the vertical axis is length, height or depth. Alternatively, if the vertical axis is time, then the height of a unit corresponds to time duration.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've tried to illustrate some of the typical layouts here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/aY5kE.png&quot; alt=&quot;Some types of stratigraphic log&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On a &lt;a href=&quot;http://en.wikipedia.org/wiki/Well_logging&quot; rel=&quot;nofollow noreferrer&quot;&gt;wireline log&lt;/a&gt;, the horizontal axis is some physical property such as natural gamma-ray emission rate or bulk density. Check the legend.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's no reason not to represent other parameters with the horizontal axis (or the vertical one, or the colour), but then you'd need to be careful about labelling things clearly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Footnote: often colour is keyed to lithology. This may or may not closely follow the grainsize. Symbols may be added to represent other relevant characteristics of the rock, such as sedimentary structures and fossils.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2014-12-29T21:17:50.220" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3159" PostTypeId="2" ParentId="2803" CreationDate="2014-12-30T06:48:07.563" Score="7" Body="&lt;p&gt;The direction of the vertical shear plays a large role in cyclogenesis, where easterly shear tends to enhance the formation of cylones and westerly shear tends to suppress it (&lt;a href=&quot;http://tinyurl.com/lbn7t65&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tuleya and Kurihara, 1981&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Internal waves are responsible for large transfers of energy across vast distances. Therefore, they play important roles in a wide array of atmospherical (and oceanic) processes, such as tropical cyclogenesis (TC). These waves are capable of depositing energy that was created far away in an already active region. This energy may manifest itself in the form of an easterly shear. Depending on the type of wave, there is evidence that some waves play an important role in triggering cyclogenesis.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It has been known for decades that about half of the hurricanes in the&#xA;  North Atlantic form from African waves (e.g., Frank and Clark 1980),&#xA;  and there have been many studies of this type of genesis (e.g.,&#xA;  Carlson, 1969; Landsea, 1993; Thorncroft and Hodges, 2001; and&#xA;  others). Molinari and Vollaro (2000), Mal- oney and Hartmann (2001),&#xA;  Liebmann et al. (1994).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There are three main classes of equatorial internal waves to consider when it comes to TC. Namely, the &lt;a href=&quot;http://www.bom.gov.au/climate/mjo/&quot; rel=&quot;nofollow noreferrer&quot;&gt;MJO&lt;/a&gt;, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/12/how-do-rossby-waves-in-the-ocean-form/521#521&quot;&gt;equatorial Rossby (ER) waves&lt;/a&gt; and other large wavenumber, high frequency waves that propagate towards the west (mixed Rossby gravity waves). Note that &lt;a href=&quot;https://en.wikipedia.org/wiki/Kelvin_wave#Equatorial_Kelvin_wave&quot; rel=&quot;nofollow noreferrer&quot;&gt;equatorial Kelvin waves&lt;/a&gt; are thought to have little effect on cyclogenesis. This animation from &lt;a href=&quot;http://www.esrl.noaa.gov/psd/map/clim/olr_modes/mapanim2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA&lt;/a&gt; shows the internal waves (as &lt;a href=&quot;https://climatedataguide.ucar.edu/climate-data/outgoing-longwave-radiation-olr-avhrr&quot; rel=&quot;nofollow noreferrer&quot;&gt;OLR anomalies&lt;/a&gt;) over a period of 40 days: &lt;img src=&quot;https://i.stack.imgur.com/ARKXB.gif&quot; alt=&quot;internal waves&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Specifically: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the MJO and ER waves produce easterly shear anomaly at the generation location, while the MJO tends to reduce westerly shear over the atlantic.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the MJO enhances both the convergence and the low-level rotation at the genesis location. [...] shows a tendency for the MJO to cause easterly vertical shear anomalies at the genesis location in most basins, and this would tend to be favorable for storm formation.  [...] The ER waves also appear to enhance genesis by increasing both the&#xA;   large-scale rotation and convection, as in this band the storms form&#xA;   within the low-level cyclonic gyre and about two days after the wave’s&#xA;   convective anomaly first reaches the genesis point. The ER waves also&#xA;   cause significant easterly shear anomalies at the genesis locations in&#xA;   about half of the basins.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Basically, internal waves enhance the formation of cyclones by increasing the vorticity of the local flow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anantha R. Aiyyer and Chris Thorncroft, 2006: &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/jcli3685.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climatology of Vertical Wind Shear over the Tropical Atlantic.&lt;/a&gt; J. Climate, 19, 2969–2983. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tuleya, Robert E., and Yoshio Kurihara. &quot;&lt;a href=&quot;http://tinyurl.com/lbn7t65&quot; rel=&quot;nofollow noreferrer&quot;&gt;A numerical study on the effects of environmental flow on tropical storm genesis.&lt;/a&gt;&quot; Monthly Weather Review 109.12 (1981): 2487-2506.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;William M. Frank and Paul E. Roundy, 2006: &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/MWR3204.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Role of Tropical Waves in Tropical Cyclogenesis.&lt;/a&gt; Mon. Wea. Rev., 134, 2397–2417. &lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2014-12-30T06:48:07.563" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3160" PostTypeId="1" CreationDate="2014-12-30T08:01:55.507" Score="8" ViewCount="1000" Body="&lt;p&gt;Assuming I have time evolution of air temperature, air pressure, wind speed, wind direction, relative humidity and cloudiness, how can I predict weather based on this information? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that high air pressure increases chance of more concentrated sunlight and low air pressure increases chance of precipitation. I know that a decrease in temperature increases chance of snow or ice and also of low relative humidity and vice versa. I also know that higher wind speed means higher chance of a storm and that certain directions of wind can cause a change in temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However I don't know what meteorological parameters I could predict with a combination of these variables. How would I predict the weather based on the time evolution of these variables?&lt;/p&gt;&#xA;" OwnerUserId="1388" LastEditorUserId="192" LastEditDate="2014-12-30T18:37:48.043" LastActivityDate="2014-12-31T05:39:50.220" Title="Statistical weather prediction" Tags="|meteorology|weather-forecasting|statistics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3161" PostTypeId="2" ParentId="2528" CreationDate="2014-12-30T09:27:00.233" Score="7" Body="&lt;p&gt;Yes, and this has been done since at least the mid 19th century (Răducanu, 2006) initially it was done to keep up with the demand, but now is a source of scrutiny for valuation of samples (Pederson and Williams, 2011; Răducanu, 2006).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Imitations have been produced by heating the following (Răducanu, 2006):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Polymers, such as polyester and polystyrene&lt;/li&gt;&#xA;&lt;li&gt;Casein&lt;/li&gt;&#xA;&lt;li&gt;Glass&lt;/li&gt;&#xA;&lt;li&gt;Celluloid&lt;/li&gt;&#xA;&lt;li&gt;Other resins, such as phenolic resin&lt;/li&gt;&#xA;&lt;li&gt;Copal - this is referred to as 'pre-amber tree resin', a natural intermediary substance between tree resin and amber.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Both Răducanu, 2006 and Pederson and Williams list several techniques as to how to tell them apart from authentic amber.  Pederson and Williams, 2011, also detail that some artificial samples are so close to amber that spectroscopy techniques are required to tell them apart.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pederson and Williams, 2011, &lt;a href=&quot;http://www.stonegrouplabs.com/Copal-vs-Amber.pdf&quot;&gt;Copal vs. amber&lt;/a&gt;, &lt;em&gt;Organics&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Răducanu, 2006, &lt;a href=&quot;http://www.upg-bulletin-se.ro/archive/2006-2/3.%20Raducanu.pdf&quot;&gt;Actual Exigencies Concerning the Quality of Amber&#xA;Pieces Commercialized in Romania&lt;/a&gt;, &lt;em&gt;Universităţii Petrol – Gaze din Ploieşti&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-12-30T09:27:00.233" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3162" PostTypeId="2" ParentId="3160" CreationDate="2014-12-30T13:26:56.577" Score="7" Body="&lt;p&gt;You need a model. You could try to use Bayes theorem to build a model based upon conditional probabilities. See this reference from NOAA about weather forecasting: &lt;a href=&quot;http://www.nssl.noaa.gov/users/brooks/public_html/prob/Probability.html&quot; rel=&quot;nofollow&quot;&gt;Probability Forecasting - Primer&lt;/a&gt; . &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I were to try to build a Bayesian model for weather forecasting, with the intention of using a limited data set of observations I had collected myself, I would look into existing software frameworks to see if I could use one of these. For example, the &lt;a href=&quot;http://research.microsoft.com/en-us/um/cambridge/projects/infernet/&quot; rel=&quot;nofollow&quot;&gt;Infer.NET framework&lt;/a&gt; is available for free, and has several examples which would be a good starting point for learning about probabilistic modeling. &lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorUserId="178" LastEditDate="2014-12-31T05:39:50.220" LastActivityDate="2014-12-31T05:39:50.220" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3163" PostTypeId="1" CreationDate="2014-12-30T15:35:13.090" Score="11" ViewCount="1109" Body="&lt;p&gt;Parícutin Volcano, sometimes referred to as the 'A Volcano Born in a Mexican Cornfield' (which is also the title of a book published in 1993, more information &lt;a href=&quot;http://www.volcano.si.edu/learn_products.cfm?p=6&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;), was one of the most well documented and observed volcanic eruptions in the world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quite literally, it grew out of a fissure in a cornfield in February 1943, continuously erupting until 1952.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/GxlIH.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Parícutin Volcano image from the USGS in 1946.  Image source: &lt;a href=&quot;http://volcano.oregonstate.edu/paricutin&quot; rel=&quot;noreferrer&quot;&gt;Oregon State University Volcano World&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What does the evidence suggest for precursor geological processes occurring immediately prior to the Parícutin Volcano eruption in 1943?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="111" LastEditDate="2015-07-07T18:16:19.547" LastActivityDate="2015-07-07T18:16:19.547" Title="What precursor geological activity occurred prior to the Parícutin Volcano eruption in 1943?" Tags="|volcanology|volcanic-eruption|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3164" PostTypeId="2" ParentId="3163" CreationDate="2014-12-30T15:35:13.090" Score="9" Body="&lt;p&gt;The region around the Parícutin volcano is within the Trans-Mexican Volcanic Belt and is affected by the subduction of the Cocos and Rivera Plates (Gardine et al. 2011), as seen in the image below (from Langridge et al. 2013):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/TlJwJ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the petrology is very recent, it has provided scientists an unprecedented opportunity to study a complete volcanic sequence. Petrological observations reported by Erlund et al. (2010) determined that there were 3 main distinct phases of volcanic activity, the initial phase, which lasted only about 4 months, is what is relevant to this question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Erlund et al. (2010) extensively studied the basal tephra, their results suggest the following occurred immediately prior to the 1943 eruption:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;magma ascended from depth through dyke and sill systems quick enough to prevent substantial fractionation from olivine settling.&lt;/li&gt;&#xA;&lt;li&gt;magma was stalled at shallow depths under sufficient pressure to allow plagioclase phenocryst growth.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;This magma movement is likely to have caused the ~45 days of seismic activity that was noted before the fissure opened up in the cornfield, initiating the Parícutin volcano eruption.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a more modern day analogue to the associated seismicity, based on models developed by Gardine et al. (2011) from an earthquake swarm that occurred near to the Parícutin volcano in 2006, where the low magnitude earthquake swarms occurred in clusters that demonstrated reasonably rapid ascent and lateral movement - suggesting not only a possible mechanism for magma ascent, but also demonstrates the region is still very active.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Erlund et al. 2010, &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0377027309003771&quot; rel=&quot;noreferrer&quot;&gt;Compositional evolution of magma from Parícutin Volcano, Mexico: The tephra record&lt;/a&gt;, &lt;em&gt;Journal of Volcanology and Geothermal Research&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gardine et al. 2011, &lt;a href=&quot;http://www.aeic.alaska.edu/input/west/papers/2011_bullVolc_gardine_paricutin.pdf&quot; rel=&quot;noreferrer&quot;&gt;Dike emplacement near Parícutin volcano, Mexico in 2006&lt;/a&gt;, &lt;em&gt;Bulletin of Volcanology&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Langridge et al. 2013, &lt;a href=&quot;http://www.scielo.org.mx/scielo.php?pid=S1026-87742013000300001&amp;amp;script=sci_arttext&quot; rel=&quot;noreferrer&quot;&gt;Preliminary paleoseismic results from the Pastores fault and its role in the seismic hazard of the Acambay graben, Trans-Mexican Volcanic Belt, Mexico&lt;/a&gt;, &lt;em&gt;Revista mexicana de ciencias geológicas&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2014-12-30T15:35:13.090" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3165" PostTypeId="1" AcceptedAnswerId="3168" CreationDate="2014-12-30T20:31:47.517" Score="12" ViewCount="1741" Body="&lt;p&gt;I tried in vain to find the answer to this question on the web, but all it would tell me was, &quot;it is very deep&quot;, and &quot;it is known as a thaw line rather than a frost line in the arctic and antarctic&quot;. How far down you would have to live to escape the permafrost? 100 ft? 1000 ft? 10000 ft?. How feasible would an underground base be?&lt;/p&gt;&#xA;" OwnerUserId="1389" LastEditorUserId="2470" LastEditDate="2021-07-06T07:03:45.490" LastActivityDate="2021-07-06T07:03:45.490" Title="How deep is the permafrost in the Antarctic?" Tags="|ice|ice-sheets|antarctica|permafrost|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3166" PostTypeId="2" ParentId="2893" CreationDate="2014-12-31T05:09:50.043" Score="2" Body="&lt;p&gt;This is essentially a part answer and it is hoped people from other basins such as Pacific, Atlantic, etc will corroborate and perhaps extend the findings. &#xA;Providing an explanation for color of oceanic waters without objective satellite/buoy data may at best be subjective. &#xA;This answer will attempt to provide an explanation based on work done in two basins - Bay of Bengal as well as Arabian Sea. &#xA;Vinayachandran et al &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2003GL018533/pdf&quot; rel=&quot;nofollow&quot;&gt;1&lt;/a&gt; address the issue by relating phytoplankton blooms to coastal upwelling caused by Ekman transport. While my observations of the aquamarine color were initially noted  during the summer monsoon the same authors have established the correlation of phytoplankton blooms to Ekman transport during the autumn monsoon as well as shown in this paper of Vinayachandran et al &lt;a href=&quot;http://caos.iisc.ernet.in/pub/vinay/bloom.pdf&quot; rel=&quot;nofollow&quot;&gt;2&lt;/a&gt;. A more recent paper talks of the same phenomenon for the Arabian Sea &lt;a href=&quot;http://www.nerci.in/pdf/IJMS.pdf&quot; rel=&quot;nofollow&quot;&gt;3&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regards to the non locality and the transient nature of the observations as most of the work is qualitative it is hoped that a quantification of the work via observational studies and modeling work will provide some of the answers.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From a layperson's perspective the idea that the color of oceans can actually provide a hint about the occurrence of an important  climatological phenomenon such as the Indian Ocean Dipole(IOD) is rewarding by itself.&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2014-12-31T07:17:47.930" LastActivityDate="2014-12-31T07:17:47.930" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="3167" PostTypeId="1" AcceptedAnswerId="4484" CreationDate="2014-12-31T09:17:09.727" Score="21" ViewCount="6922" Body="&lt;p&gt;It seems like the only personal protective equipment&#xA;(PPE) that volcanologists use are aluminized suits that don't provide any protection from direct contact with lava, making an unexpected splash lethal. There are suits that firefighters use to go directly into fires for prolonged periods of time, and they are able to resist temperatures exceeding 1100 °C (~2000 °F) for up to 15 minutes at a time. Most lava is around this temperature threshold, with the coolest lava erupting at a mere 650 °C (~1200 °F).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why don't volcanologists use these suits to study volcanoes? Instead of using those awkward long metal rods to pick out the right piece of lava to study, couldn't they use their gloved hands to pick it up (perhaps on the colder erupting lavas like the ones that does so at 650 °C)?&lt;/p&gt;&#xA;" OwnerUserId="1391" LastEditorUserId="595" LastEditDate="2015-03-06T10:30:19.370" LastActivityDate="2020-01-29T14:24:55.823" Title="Why don't scientists use fire entry suits to study volcanoes?" Tags="|volcanology|geothermal-heat|volcanic-hazard|magmatism|" AnswerCount="3" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="3168" PostTypeId="2" ParentId="3165" CreationDate="2014-12-31T14:08:56.363" Score="6" Body="&lt;p&gt;According to &quot;&lt;a href=&quot;http://erth.waikato.ac.nz/antpas/pdf/BOCKHEIM-PRINT.pdf&quot;&gt;Permafrost, active-layer dynamics and periglacial environments of continental Antarctica&lt;/a&gt;&quot; South African Journal of Science 98. pages 82-90:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Only 25% of Antarctica has permafrost, as the material beneath thick ice sheets is not permafrost. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The deepest permafrost occurs where there is no ice sheet. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The deepest permafrost in the Antarctic is about 1000m.&lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2014-12-31T14:08:56.363" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3169" PostTypeId="1" AcceptedAnswerId="3173" CreationDate="2014-12-31T14:20:28.293" Score="10" ViewCount="11802" Body="&lt;p&gt;Is the temperature (even a bit) warmer in a forest?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, there no frost on the ground in a forest when there is some in a field just outside the forest. Is it because the temperature is a bit warmer? Or simply because there is no dew on the ground in a forest?&lt;/p&gt;&#xA;" OwnerUserId="1315" LastActivityDate="2023-04-18T12:45:59.783" Title="Is the temperature (even a bit) warmer in a forest?" Tags="|temperature|forest|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="3170" PostTypeId="2" ParentId="2893" CreationDate="2015-01-01T01:47:03.770" Score="6" Body="&lt;p&gt;The relationship of the observed &quot;aquamarine color&quot; near the coast and the Ekman pumping in the open ocean, while possible is rather unlikely. Ekman pumping is confined to the areas affected by the cyclonic wind stress curl and by definition it is mostly effective in the open ocean, where there is no bottom boundary effect. The color of the coastal waters is likely more affected by the upwelling-favorable wind creating upwelling conditions that provide nutrients to the coastal areas. The fact that the color is affected by the sea-breeze is even more justification for the upwelling mechanism. While transport of nutrient-rich waters to the coastal areas is not uncommon, the time scales associated with primary production especially in coastal areas are quite fast and tend to use the open-ocean nutrients in short time scales. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Phytoplankton changes especially on the order of hours are more likely associated with purely coastal processes. While there might be an input of open-ocean nutrients to the coastal areas, the coastal primary production tends to differ from open-ocean communities and tend to respond rapidly to extra nutrients.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The aquamarine color could be the result of many coastal processes. Without knowing the area, I don't feel qualified to make a strong case about the causes. Reasons for the color could include 1) vertical phytoplankton migrations that settle to the bottom/lower water column when the breeze comes up; 2) the sea breeze resulting on a local near-shore downwelling; 3) a breakdown of the stratification by the breeze that mixes down the surface layers; 4) regional features (e.g., sea level pressure gradient) that become active when the breeze is occurring. Too many unknowns for me. It would be good to know the extent and duration of the &quot;aquamarine color&quot; patch, the width and slope of the continental shelf in the area and the ind and stratification conditions in the near-shore and coastal areas.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-01-01T01:47:03.770" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3171" PostTypeId="2" ParentId="3114" CreationDate="2015-01-01T02:45:39.597" Score="3" Body="&lt;p&gt;The current answer is &lt;strong&gt;uncertain&lt;/strong&gt;, especially with recent observations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Zahn (2003) outlined that despite the possibility of noctilucent clouds (NLC) being sensitive to water vapour mixing ratios and temperature, there are 3 main concerns as to the link between the frequency of NLC occurrences and climate change:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;NLC observations have shown a great variability (including in frequency) since they were first described in 1885.&lt;/li&gt;&#xA;&lt;li&gt;There has been no significant variation in altitude&lt;/li&gt;&#xA;&lt;li&gt;The timeframe of observing this phenomena is too short to fully delineate natural and anthropogenic forcings.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;In 2007, the AIM (&lt;a href=&quot;http://aim.hamptonu.edu/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Aeronomy of Ice in the Mesosphere&lt;/a&gt;) mission was launched to explore NLC and related phenomena, in particular, the SOFIE (&lt;a href=&quot;http://sofie.gats-inc.com/sofie/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Solar Occultation for Ice Experiment&lt;/a&gt;) instrument.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In recent observations, reported in the NASA article &lt;a href=&quot;http://science.nasa.gov/science-news/science-at-nasa/2014/16apr_teleconnections/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Unexpected teleconnections in noctilucent clouds&lt;/a&gt; in 2014 found that the winter air temperature over the USA and Arctic stratospheric conditions have a direct link to the frequency of NLC over Antarctica (as per the image below from NASA):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/ARJAV.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Note: PMC is often used synonymously with NLC&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This suggests that changes in winter temperatures on the opposing hemisphere may indeed alter the frequency of NLC occurrences.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, other influences are being investigated, such as solar cycles, observations and research from the CAWSES II &lt;a href=&quot;http://www.cawses.org/CAWSES/Home.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate and Weather of the Sun-Earth System&lt;/a&gt; mission have found that there appears to be a correlation between NLC frequency and solar flux, as seen in the graph below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/y36t6.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image source: &lt;a href=&quot;http://www.cawses.org/wiki/index.php/Project_3_PMC/NLC_altitude,_frequency_and_brightness_changes_related_to_changes_in_dynamics_and_chemical_composition&quot; rel=&quot;nofollow noreferrer&quot;&gt;Project 3 PMC/NLC altitude, frequency and brightness changes related to changes in dynamics and chemical composition&lt;/a&gt; (Thomas et al.).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This all ties in with Zahn's 3rd doubt - more data from multiple observations are needed in order to fully determine whether or not the frequency of NLC has any relationship with climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Reference&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Zahn, 2003, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2003EO280001/pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Are Noctilucent Clouds&#xA;a &quot;Miner's Canary&quot; for&#xA;Global Change?&lt;/a&gt; &lt;em&gt;EOS&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2015-01-01T02:45:39.597" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3172" PostTypeId="1" CreationDate="2015-01-01T06:05:47.220" Score="8" ViewCount="649" Body="&lt;p&gt;For example, &lt;a href=&quot;http://water.usgs.gov/edu/sinkholes.html&quot;&gt;sinkholes&lt;/a&gt; can be human induced:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;New sinkholes have been correlated to land-use practices, especially&#xA;  from groundwater pumping and from construction and development&#xA;  practices. Sinkholes can also form when natural water-drainage&#xA;  patterns are changed and new water-diversion systems are developed.&#xA;  Some sinkholes form when the land surface is changed, such as when&#xA;  industrial and runoff-storage ponds are created. The substantial&#xA;  weight of the new material can trigger an underground collapse of&#xA;  supporting material, thus causing a sinkhole.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;We have been pumping oil out of the ground, fracking, extracting natural gas, mining, etc. for a long time now and in some instances to the point that we completely deplete such reserves. What is the long term impact of anthropogenic removal of material from the underground on the ability of the foundational soil to support our ever expanding population and associated infrastructure? &lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2015-01-01T06:35:46.340" LastActivityDate="2015-01-03T06:07:41.003" Title="What is the long term impact of large scale removal of material from subterraneal caches on the structural integrity of the soil?" Tags="|geophysics|geology|mining|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="3173" PostTypeId="2" ParentId="3169" CreationDate="2015-01-01T06:15:02.370" Score="16" Body="&lt;p&gt;It will depend on the time of year and the time of day. As you noted, you often see more frost in an open field than in a forest. A comment indicated the forest insulated the surface but I believe it will also reduce radiant heat loss at night, compared to the open field. During the day, the ground surface is more shaded and the trees reduce the advective movement of warmer air into the forest floor so the forest will often be cooler than the open field.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another factor is evapotranspiration. Forests will tend to be cooler in drier summer conditions because, in general, you get more evapotranspiration from trees than from shallow-rooted vegetation and annual grasses die off in summer. The evapotranspiration cools the area. &lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2015-01-01T06:15:02.370" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3174" PostTypeId="1" CreationDate="2015-01-01T06:48:01.273" Score="13" ViewCount="180" Body="&lt;p&gt;The two great basins - Indian Ocean and Pacific Ocean have their respective oscillations: Indian Ocean Dipole and El Nino Southern oscillation that affect the climate of the regions as well as the world at large. Is there any scientific agreement that the two basins are coupled at the oceanic level and the atmospheric level ? What are the observable manifestations of this coupling between basins?&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorUserId="22648" LastEditDate="2021-07-22T08:53:37.770" LastActivityDate="2022-12-27T20:54:30.113" Title="Oceanic-atmospheric coupling between the Indian Ocean and the Pacific Ocean basins" Tags="|oceanography|enso|climatology|ocean-models|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="3175" PostTypeId="2" ParentId="14587" CreationDate="2015-01-01T07:20:51.587" Score="8" Body="&lt;p&gt;It literally means that the water depth will be 0.5mm. For example, if you place a container under the rain and it fills up to 0.5mm, then the precipitation is 0.5mm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Despite the fact that a wide container requires more rain to fill up than a narrow container, the larger surface area allows it to collect the right amount of rain water to fill up to the same amount as the narrow container in the same amount of time (as long as the walls are vertical). Therefore, if the rainfall is 1 mm, every square meter receives 1 liter of rain water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Addendum:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By the way, tuna cans can be distributed along your lawn to serve as a very primitive, but very cheap measurement tool that you can use to create a spatial map of what your irrigation system is doing. You can use that for troubleshooting your efficiency, 1 full can is 1 inch irrigation/rainfall.&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2015-01-01T08:12:24.583" LastActivityDate="2015-01-01T08:12:24.583" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="3176" PostTypeId="1" CreationDate="2015-01-02T09:11:32.207" Score="9" ViewCount="3673" Body="&lt;p&gt;Related to the question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/3167/why-dont-scientists-use-fire-entry-suits-to-study-volcanoes&quot;&gt;Why don't scientists use fire entry suits to study volcanoes?&lt;/a&gt;, where the issue of volcanologist protection against lava splatter and bombs is discussed.  Another major and sometimes sudden volcanic event are &lt;a href=&quot;http://volcanoes.usgs.gov/hazards/pyroclasticflow/&quot; rel=&quot;nofollow noreferrer&quot;&gt;pyroclastic flows&lt;/a&gt; - the suddenness and swiftness of these events have occurred in many places, one recent example is the recent tragedy that occurred at Mt. Ontake, Japan, discussed in the question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2545/why-would-volcano-eruption-cause-cardiac-arrest&quot;&gt;Why would volcano eruption cause cardiac arrest?&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are many examples of volcanologists perishing due to pyroclastic flows.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Around some volcanoes in Japan, for example, there are reinforced concrete shelters touted as being pyroclastic flow shelters, as shown below on Oshima Island:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/mH49m.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://sio.ucsd.edu/japan/journal/0723/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From personal experience, these shelters also surround Mt. Asama (have visited there).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How effective are these concrete shelters for survival against pyroclastic flows?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;additionally, &lt;strong&gt;has there been any research for the development of protective gear against pyroclastic flows?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2018-03-27T15:09:32.093" Title="Pyroclastic flow protection" Tags="|volcanology|volcanic-hazard|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3178" PostTypeId="2" ParentId="3176" CreationDate="2015-01-03T00:32:44.613" Score="7" Body="&lt;p&gt;Pyroclastic flows have often been considered to be by and large, unsurvivable, especially since the devastation in 1902 of St. Pierre on Martinique, many fatalities are due to hypoxia and severe thermal injuries (Hansell et al. 2006; Baxter et al. 1998).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the USGS &lt;a href=&quot;http://volcanoes.usgs.gov/hazards/pyroclasticflow/&quot; rel=&quot;noreferrer&quot;&gt;webpage about pyroclastic flows&lt;/a&gt;, these events can occur very suddenly, without much warning at all (e.g. Mt. Ontake) and travel fast, and can be several hundreds of degrees Celsius. Pyroclastic flows also contain considerable amounts of toxic gases and rock fragments.  The presence of water bodies in the path can result in lahars and mudflows.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As pyroclastic flows are variable in nature and can be sudden, there is no one-way of volcanologists protecting against its effects, except to get out of the way (if possible).  The use of fire suits will limit mobility and still may not protect from the flow itself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the AGU blog &lt;a href=&quot;http://blogs.agu.org/magmacumlaude/2013/02/24/so-you-want-to-be-a-volcanologist/&quot; rel=&quot;noreferrer&quot;&gt;So you want to be a volcanologist?&lt;/a&gt;, Jessica Bell, a volcanologist from the USGS makes the point that being prepared is crucial for greater chances of survival, emphasising the point of 'doing your homework' about the eruptive history of the volcano &lt;em&gt;before&lt;/em&gt; going to the volcano.  Gas masks, gloves, long sleeves and long pants are also crucial.  Critically, a volcanologist must be:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;very careful to avoid areas that could be dangerous – within the path of pyroclastic flows or mudflows or lava bombs, near gas vents or lava flows, or unstable ground are just a few.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It should be noted that several media reports mention that not all volcanoes have these kinds of shelters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But where the shelters are present, they could provide an obstacle that could affect pyroclastic flow propogation but only when the shelter is distal to the eruption and if the flow does not last too long, related to modelling performed by Todesco et al. (2006) and earlier by Baxter et al. (1998) who assert that this situation is survivable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Baxter et al. (1998) also state that through their models, the most effective shelters can shield against the dynamic pressure and heat transfer associated with a pyroclastic flow, especially if the flow is of short duration.  This effectiveness obviously diminishes when the flow lasts a considerable amount of time, is large-scale or the shelter is too close to the eruptive source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What these shelters won't protect from is fine ash dust, and not everyone sheltering will necessarily have a gas mask (as per the volcanologist above).  Another problem with this, as noted after the Mt. Unzen eruption of 1991 is that even if shelters are spaced evenly apart - time is a major factor - the time to reach the shelter against the time it takes for the pyroclastic flow to reach that location.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A lot of shelters around some volcanoes that have had a past history of pyroclastic flows have 'exclusion zones' with the shelters in the distal regions of previous eruptions, this method of exclusion zones is claimed by Hansell et al. (2006) as being one of the only effective protective measures from proximal effects of an expected pyroclastic flow - which also describes, alongside the modelling by Baxter et al. (1998), the way that these shelters can have any effectiveness by being in the distal regions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Baxter et al. 1998, &lt;a href=&quot;http://link.springer.com/article/10.1023/A:1008031004183&quot; rel=&quot;noreferrer&quot;&gt;Physical Modelling and Human Survival in Pyroclastic Flows&lt;/a&gt;, &lt;em&gt;Natural Hazards&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hansell et al. 2006, &lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2078062/&quot; rel=&quot;noreferrer&quot;&gt;The health hazards of volcanoes and geothermal areas&lt;/a&gt;, &lt;em&gt;Occupational Environmental Medicine&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Takahashi, 2007, &lt;a href=&quot;http://www.sabo-int.org/projects/unzen_01.pdf&quot; rel=&quot;noreferrer&quot;&gt;Unzen-Fugendake Eruption Executive Summary 1990－1995&lt;/a&gt;, &lt;em&gt;Unzen Restoration Project Office,&#xA;Kyushu Regional Construction Bureau,&#xA;Ministry of Land, Infrastructure and Transport&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Todesco et al. 2006, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2006GC001314/full&quot; rel=&quot;noreferrer&quot;&gt;Pyroclastic flow dynamics and hazard in a caldera setting: Application to Phlegrean Fields (Italy&lt;/a&gt; &lt;em&gt;Geochemistry, Geophysics, Geosystems&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2015-01-03T00:32:44.613" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3179" PostTypeId="2" ParentId="1044" CreationDate="2015-01-03T02:01:11.097" Score="6" Body="&lt;p&gt;The mantle of Mars is heterogeneous. While there are many things that are unknown about the Martian mantle and the entire internal structure of Mars, this is not one of them. The source of this finding comes from the analysis of meteorites originating from Mars.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Analysis shows that 4.5 billion years ago - when Mars was forming along with the rest of the solar system - two distinct &quot;reservoirs&quot; formed in the mantle - the &quot;Enriched Reservoir&quot; (ER) and the &quot;Depleted Reservoir&quot; (DR). The ER had high ratios of lanthanum/ytterbium and $^{87}$Sr/$^{86}$Sr, and a low ratio of samarium/neodymium. The DR had the opposite ratios.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Eventually, meteorites known as &lt;a href=&quot;http://www.psrd.hawaii.edu/PSRDglossary.html#shergottite&quot; rel=&quot;nofollow&quot;&gt;shergottites&lt;/a&gt; formed, mixtures of both of these reservoirs. A graph (which I'd insert here, but I'm unsure of the copyright on it) entitled &quot;Heterogeneous Martian Mantle&quot; illustrates how these meteorites have a wide range of composition compared to rocks from Earth. This provides compelling evidence for a heterogeneous Martian mantle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the moment, I can't find enough information to answer the follow-up part, though the convection certainly did stop.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Sources:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.psrd.hawaii.edu/Oct12/Mantle-of-Mars.html&quot; rel=&quot;nofollow&quot;&gt;PSRD article 1&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.psrd.hawaii.edu/June04/martianMantle.html&quot; rel=&quot;nofollow&quot;&gt;PSRD article 2&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1399" LastEditorUserId="64" LastEditDate="2015-01-07T02:29:05.883" LastActivityDate="2015-01-07T02:29:05.883" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3180" PostTypeId="2" ParentId="3110" CreationDate="2015-01-03T02:58:31.717" Score="4" Body="&lt;p&gt;Good paper you reference there.  I think you are starting to answer some of your question by noting that Bradley associates the absence in passive margins with the Nuna supercontinent.  All &quot;rifting&quot; / spreading is taking place in the oceans - pretty much a requirement for supercontinents,  and in this case all continental margins (or at least for those with surviving geological record) were destructive margins.  Over time the duration of passive margins has changed.  For more recent supercontinents you mention, the shorter cycle of a passive margin may have made it very unlikely that tectonic events could cause a simultaneous gap in all passive margins.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As Bradley points out in his conclusions, tectonic activity when Nuna was around may have been globally more sluggish that today, or during the time of Rodinia and Pangea. It may also tie in with the formation of some mineral deposits.  For example, there is a peak in porphyry deposits at about this time.  Now taking into account that older porphyry deposits are less like to have survived (lost through erosion, buried or consumed in later tectonics) the peak at this time may reflect that it was a particularly good porphyry generation time for so many to have survived.  Porphyries do like convergent margins and there would have been lots of those.&lt;/p&gt;&#xA;" OwnerUserId="1396" LastEditorUserId="1396" LastEditDate="2015-01-03T04:34:17.250" LastActivityDate="2015-01-03T04:34:17.250" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3181" PostTypeId="2" ParentId="3167" CreationDate="2015-01-03T03:11:44.270" Score="11" Body="&lt;p&gt;I think the answer to &quot;Why don't scientists use fire entry suits to study volcanoes?&quot; is that this is a question of professional ethics rather than of technology. For some institution to support, condone, or fund such a proposal, it would first have to conduct some sort of a safety review.  At a significant cost, this approach would encourage risky behavior, put personnel into greater danger, and for small gains that could be obtained by safer alternatives. I expect most university, research or governmental agencies would decide this would be unethical to support because it may encourage greater risk-taking and injury to their technicians. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although firefighters may use such protective suits, their objective is to save the lives of others. Although manned space flight is also a highly risky project, the payoff is potentially much higher and there may be no practical alternatives. There are safer ways to obtain a sample of fresh lava - a long pole or a robot. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's very sad that there have been some fatal accidents of persons observing volcanos. To my knowledge however, the sort of 'protective' wear you suggest would not have saved lives in these cases, the circumstances were devastatingly powerful, explosive, and catastrophic and not the sort of risk technicians experience in industry. Examples of 'acceptable-risk' in this would be something comparable to what a worker in a steel foundry or glass-blowing shop might experience. Do these workers use such suits? Volcanologists should at least take the same level of precaution as comparable industrial workers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my answer is that the question is not entirely technical, once lives are involved there are ethical questions as well.       &lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorUserId="178" LastEditDate="2015-01-03T17:49:59.750" LastActivityDate="2015-01-03T17:49:59.750" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3182" PostTypeId="2" ParentId="3169" CreationDate="2015-01-03T04:48:05.490" Score="10" Body="&lt;p&gt;Don't forget the protection from wind in colder seasons as well.  Basic survival skill is to always make shelters under cover (as in a forest) rather than in an open meadow.  On a cold day it may not feel much warmer in still air but getting out of the wind does make a significant difference.&lt;/p&gt;&#xA;" OwnerUserId="1396" LastActivityDate="2015-01-03T04:48:05.490" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="3183" PostTypeId="1" AcceptedAnswerId="3188" CreationDate="2015-01-03T05:14:21.670" Score="10" ViewCount="277" Body="&lt;p&gt;I'm studying the Wavewatch III wave model (&lt;a href=&quot;http://polar.ncep.noaa.gov/waves/index2.shtml&quot;&gt;http://polar.ncep.noaa.gov/waves/index2.shtml&lt;/a&gt;). I'm confused by the stability correction factor, named ASF in the code. What is its purpose? Is it related to the physics, or is it something to do with numerical methods and the CFL condition? I could not immediately figure this out from the code.&lt;/p&gt;&#xA;" OwnerUserId="1167" LastEditorUserId="192" LastEditDate="2015-01-03T15:49:27.907" LastActivityDate="2015-01-11T12:03:50.753" Title="Stability correction factor in the Wavewatch III wave model" Tags="|models|waves|numerical-modelling|wave-modeling|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3184" PostTypeId="2" ParentId="3172" CreationDate="2015-01-03T06:07:41.003" Score="6" Body="&lt;p&gt;The answer to your question will depend on the type of material and the depth. I will restrict this answer to groundwater withdrawal to focus the discussion.  Of course there can be effects from other extractive industries. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Groundwater pumping can lead to large scale subsidence, with the &lt;a href=&quot;http://ca.water.usgs.gov/projects/central-valley/land-subsidence-monitoring-network.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Central Valley of California being one of the best described examples&lt;/a&gt;. According to that website, &quot;More than 80 percent of the identified subsidence in the United States is a consequence of human impact on subsurface water.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/5bWDC.jpg&quot; alt=&quot;Approximate location of maximum subsidence in the U.S., identified by research efforts of Dr. Joseph F. Poland (pictured). &quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Overall, the extreme subsidence shown may cause damage to foundations, etc. but is spread over a large area and is pretty even, unlike your classic sink-hole.  It is the differential settling that causes the most damage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are several types of sink holes (also called dolines), they may be related to failure of indurated rock above cavities or by failure of soft soils/sediments. The most common natural sinks occur through the dissolution of limestone in 'karst' terrain and they can be kilometers across. This can lead to the creation of water or air filled caves. In some cases a cavity forms in sediments above the limestone and can subsequently collapse. Cavities can also be formed in sediments where they are removed through pipe erosion but that tends to be a shallow phenomenon (but can still be damaging).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The description, above, talks about natural processes but these can be enhanced by groundwater pumping.  The water supports some of the overburden and removing it weakens the structure and can lead to collapse. Flow systems can change, enhancing subsurface soil erosion as water tables decline. And of course, building over a cavity may exceed the load bearing capacity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the long term impacts will depend on both the geologic setting and the severity of water level decline. Will this have a major effect on global infrastructure and economies? I suspect not but the damage we have seen in certain areas is likely to continue and perhaps spread.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A somewhat old but good reference on the subject sinkholes and caves that discusses the land-use issues is Geomorphology and Hydrology of Karst Terrains. White, William B. (1988). Oxford University Press. &lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2015-01-03T06:07:41.003" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3185" PostTypeId="2" ParentId="3121" CreationDate="2015-01-03T06:28:36.197" Score="5" Body="&lt;p&gt;Adding to Sabre Tooth's summary:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to weathering of felsic volcanics as ST describes, another aspect that has received attention over the years has been direct input to the salar (or playa) from hot spring sources.  The idea being that the lithium is coming in as magmatic, not just meteoric  water.  There is no question that hot springs are typically associated with lithium brines - but since the causal relationship is not yet conclusive, there could be an underlying confounding variable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A paper published recently by Daisuke Araoka (2013), notably covering the same part of Nevada as Hofstra (2013), finds isotopic evidence for the hot spring source over the weathering of felsic volcanics.  So the debate is not quite over.  There are some unusually high Li levels in silver and gold vein mineralization adjacent to Clayton Valley.  I'm not sure how that fits in - the Ag-Au mineralization is quite a bit older but it could still relate to the bigger story.  I don't know the Uyuni area as well as Argentine salares, but I don't think the hot spring model has been pushed there too much although I do hair it mentioned in Argentina occasionally.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good geochemical discussion on sources in the Andes is provided in Risacher (2003).  His work also has application in developing exploration techniques.  The amount of research (aka funding) that has gone into porphyry deposit genesis and exploration methods dwarfs the amount that has gone into lithium brines.  And much of the work that has been done has been by a few companies that have had no motivation to publish their work in the way that the academic groups researching porphyries have.  Consequently there is still work to be done in this area.  Risacher's paper, and others by him on the same subject are readable and interesting examples of applied geochemistry in genetic models and potential exploration methods.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://link.springer.com/article/10.1007/s00126-013-0495-y&quot; rel=&quot;noreferrer&quot;&gt;Araoka, D., Kawahata, H., Takagi, T., Watanabe, Y., Nishimura, K., Nishio, Y., 2013, Lithium and strontium isotopic systematics in playas in Nevada, USA: constraints on the origin of lithium, Mineralium Deposita, v, 49, is. 3, pp 371-379&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0012825203000370&quot; rel=&quot;noreferrer&quot;&gt;Risacher, F., Alonso, H., Salazar, C., 2003, The origin of brines and salts in Chilean salars—A hydrochemical review: Earth-Science Reviews, v. 63, nos. 3–4, p. 249–293.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1396" LastActivityDate="2015-01-03T06:28:36.197" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3186" PostTypeId="1" AcceptedAnswerId="3187" CreationDate="2015-01-03T13:33:05.100" Score="12" ViewCount="8268" Body="&lt;p&gt;Recently I heard that in winter season the distance between the Earth and the Sun will be closest and it is farthest in summer. If it is true then why is it hotter in summer and cooler in winter?&lt;/p&gt;&#xA;" OwnerUserId="628" LastEditorUserId="1395" LastEditDate="2015-01-05T11:59:26.123" LastActivityDate="2019-02-18T21:52:45.013" Title="Is it true that distance between earth and sun is closer in winter season (January) and farther in summer season in the Northern Hemisphere?" Tags="|earth-rotation|earth-system|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="3187" PostTypeId="2" ParentId="3186" CreationDate="2015-01-03T14:24:44.723" Score="18" Body="&lt;p&gt;Yes, it's true (in the northern hemisphere). The small eccentricity of the Earth's orbit is not anywhere close to a key driver in the seasons. The key driver of the seasons is the Earth's obliquity. In the northern hemisphere, the axial tilt of Earth's rotation axis has the northern half of the Earth facing a bit toward the Sun in June/July/August and away from the Sun in December/January/February. The opposite is true in the southern hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Eccentricity would be a driver of the seasons if the Earth's rotation and orbital axes were much closer in line with one another than they are. If that were the case, summer and winter would be world-wide phenomena. As it stands, when its summertime in the northern hemisphere its wintertime in the southern hemisphere, and vice versa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Somewhat paradoxically, even though the Earth is closest to the Sun in early January and furthest from the Sun in early July, the Earth as a whole is cooler during December/January/February than it is during June/July/August. The reason is the uneven distribution of land and ocean between the northern and southern hemispheres.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In 13000 years, northern hemisphere summers will occur near perihelion passage and winters near aphelion passage. Those will be brutal times! Fortunately, I won't be around to see them.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-01-03T14:24:44.723" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3188" PostTypeId="2" ParentId="3183" CreationDate="2015-01-03T15:48:13.080" Score="12" Body="&lt;p&gt;The stability correction factor &lt;code&gt;ASF&lt;/code&gt; is related to the effects of atmospheric stability (function of buoyancy and shear) on wave growth, and has been implemented in Wavewatch3 in the Tolman and Chalikov 1996 input source term. The code where the correction happens can be found in &lt;code&gt;w3updtmd.ftn&lt;/code&gt;:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;! 5.  Stability correction ( !/STAB2 )&#xA;!     Original settings :&#xA;!&#xA;!     SHSTAB =    1.4&#xA;!     OFSTAB =   -0.01&#xA;!     CCNG   =   -0.1&#xA;!     CCPS   =    0.1&#xA;!     FFNG   = -150.&#xA;!     FFPS   =  150.&#xA;!&#xA;!/STAB2      STAB0  = ZWIND * GRAV / 273.&#xA;!&#xA;!/STAB2      DO ISEA=1, NSEA&#xA;!/STAB2        STAB   = STAB0 * AS(ISEA) / MAX(5.,U10(ISEA))**2&#xA;!/STAB2        STAB   = MAX ( -1. , MIN ( 1. , STAB ) )&#xA;!&#xA;!/STAB2        THARG1 = MAX ( 0. , FFNG*(STAB-OFSTAB))&#xA;!/STAB2        THARG2 = MAX ( 0. , FFPS*(STAB-OFSTAB))&#xA;!/STAB2        COR1   = CCNG * TANH(THARG1)&#xA;!/STAB2        COR2   = CCPS * TANH(THARG2)&#xA;!&#xA;!/STAB2        ASF(ISEA) = SQRT ( (1.+COR1+COR2)/SHSTAB )&#xA;!/STAB2        U10(ISEA) = U10(ISEA) / ASF(ISEA)&#xA;!/STAB2        END DO&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The correction essentially accounts for atmospheric stability based on air-sea temperature difference, and is applied to calculate the &quot;effective&quot; wind speed at 10-m height, from the input wind speed. Note that this code is active only when &lt;code&gt;/STAB2&lt;/code&gt; switch is enabled (optional), and works only with the &lt;code&gt;/ST2&lt;/code&gt; switch (Tolman and Chalikov 1996 source term package). It's implementation and test results have been described in Tolman 2002.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is also documented in the manual for version 4.18, see equations (2.86)-(2.89) in section 2.3.7.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Tolman, H. L. and D. V. Chalikov, 1996: Source terms in a third-generation wind-wave model. J. Phys. Oceanogr., 26, 2,497–2,518.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Tolman, H. L., 2002: Validation of WAVEWATCH III version 1.15 for a global domain. Tech. Note 213, NOAA/NWS/NCEP/OMB, 33 pp.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2015-01-03T15:56:30.697" LastActivityDate="2015-01-03T15:56:30.697" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="3189" PostTypeId="1" CreationDate="2015-01-03T16:23:14.697" Score="15" ViewCount="1102" Body="&lt;p&gt;A 'Fire tornado' or 'Firenado' or 'Fire whirl' are a fearful feature of forest fires world wide.  Having seen one up close, I can attest that they are both awesome and utterly terrifying, but I am aware that these vortices are not strictly speaking, actual tornadoes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An example, filmed in fires in 2012 around Alice Springs, Northern Territory, Australia, as in this &lt;a href=&quot;https://www.youtube.com/watch?v=lsyvOYcWgcg&quot; rel=&quot;noreferrer&quot;&gt;YouTube Clip&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://en.wikipedia.org/wiki/Fire_whirl&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia page&lt;/a&gt; for this topic rather vaguely states&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Often, fire whirls are created when a wildfire or firestorm creates its own wind, which can turn into a spinning vortex of flame.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But, the page does provide the following public domain image of a 'fire tornado':&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/3mxY4.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How does the vortex of fire in a 'fire tornado' form?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="192" LastEditDate="2015-01-03T17:12:42.023" LastActivityDate="2018-11-27T09:38:02.803" Title="How does a 'fire tornado' form?" Tags="|meteorology|tornado|severe-weather|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="3190" PostTypeId="2" ParentId="3120" CreationDate="2015-01-03T16:31:01.100" Score="3" Body="&lt;p&gt;&lt;strong&gt;Circumstellar habitable zone&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are &lt;a href=&quot;http://www.universetoday.com/32622/habitable-zone/&quot; rel=&quot;nofollow&quot;&gt;a&lt;/a&gt; &lt;a href=&quot;http://www.britannica.com/EBchecked/topic/1674268/habitable-zone&quot; rel=&quot;nofollow&quot;&gt;few&lt;/a&gt; &lt;a href=&quot;https://en.wikipedia.org/wiki/Circumstellar_habitable_zone&quot; rel=&quot;nofollow&quot;&gt;pages&lt;/a&gt; that explain the concept in detail, but the gist is that the circumstellar habitable zone is (my definition)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The region around a star inside which a planet similar to Earth can have liquid water on it surface.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, with more detailed observations of &lt;a href=&quot;https://en.wikipedia.org/wiki/Europa_(moon)&quot; rel=&quot;nofollow&quot;&gt;Europa&lt;/a&gt;, with its possible underground ocean, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Titan_(moon)&quot; rel=&quot;nofollow&quot;&gt;Titan&lt;/a&gt;, with its hydrocarbon lakes, the definition may be modified:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The region around a star inside which a body can have liquid water, or where other compounds suited for the formation of life can arise; alternatively, the region around a gas giant where moons can be heated by tidal forces such that the compounds can exist.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The latter section, of course applies to moons only. The galactic habitable zone (see &lt;a href=&quot;http://astro.unl.edu/naap/habitablezones/ghz.html&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Galactic_habitable_zone&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;) is another - slightly less-well-defined - area where a habitable planet should lie.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can calculate the habitable zone around a star based off of what defines it: the luminosity of the star, primarily. There's a poorly-explained formula &lt;a href=&quot;http://www.astro.sunysb.edu/fwalter/AST101/habzone.html&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;, although &lt;a href=&quot;http://www.planetarybiology.com/calculating_habitable_zone.html&quot; rel=&quot;nofollow&quot;&gt;Planetary Biology&lt;/a&gt; gives a much more explicit derivation. The two important equations are these:&#xA;$$r_i = \sqrt{\frac{L_{\text{star}}}{1.1}}$$&#xA;$$r_o = \sqrt{\frac{L_{\text{star}}}{0.53}}$$&#xA;where $r_i$ and $r_o$ are the inner and outer radii, and $L_{\text{star}}$ is the luminosity of the star. Note, though, that these are for the conventional definition of the habitable zone, neglecting non-$\ce{H2O}$-based compounds and tidal heating of moons orbiting gas giants. &lt;a href=&quot;http://xxx.lanl.gov/pdf/1301.6674v2.pdf&quot; rel=&quot;nofollow&quot;&gt;This&lt;/a&gt; pre-print, by Kopparapu et al., does give another interesting formula:&#xA;$$d=\left(\frac{L/L_{\odot}}{S_{eff}} \right)^{0.5} \text{ AU}$$&#xA;where $S_{eff}$ is a parameter determined by the effective temperature $T_{eff}$ of a planet at that distance and some coefficients, as well as the Sun's $S_{eff}$. But those findings are rather new, so I'd stick with the older formulas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the habitable zone is determined primarily by the star's luminosity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Mass&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An atmosphere is generally considered a must for planets with Earth-like lifeforms. Low-mass bodies, such as the Moon, can't hold on to one, and that's one of the reasons that moons have not been of as much interest as planets have been. Atmospheres, among other things, can keep the planet at a nice temperature and allow distinct climates to form. As &lt;a href=&quot;http://triplehelixblog.com/2012/06/criteria-for-habitable-planets-and-implications-for-earth/&quot; rel=&quot;nofollow&quot;&gt;this site&lt;/a&gt; elaborates on, they also help protect the planet from radiation like UV rays. Our ozone layer is really helpful in that regard.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mass isn't the only thing that helps a body keep its atmosphere. For example, Titan is relatively low-mass (although relatively high-mass for moons), yet it still has &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Titan&quot; rel=&quot;nofollow&quot;&gt;an atmosphere&lt;/a&gt;. This is because the solar wind - which can hurt atmospheres - is so weak at Titan's distance from the Sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To expand on what gansub mentioned: Magnetic fields are important because they are extremely useful when it comes to helping a planet retain its atmosphere. As Luhmann and Russell explain in &lt;a href=&quot;http://www-ssc.igpp.ucla.edu/personnel/russell/papers/mars_mag/&quot; rel=&quot;nofollow&quot;&gt;&quot;Mars: Magnetic Field and Magnetosphere&quot;&lt;/a&gt;, Mars lost its magnetic field long ago, and so the solar wind is gradually stripping it away, albeit at a really slow rate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Rotation&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This section is based a lot on &lt;a href=&quot;http://arxiv.org/pdf/1404.4992v1.pdf&quot; rel=&quot;nofollow&quot;&gt;this paper&lt;/a&gt;, by Yang et al. It, too is recent, so keep that in mind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Before I get into the paper, I'll say this: Rotation helps because it keeps one side of the planet from being baked while the other side freezes. &lt;a href=&quot;https://en.wikipedia.org/wiki/Tidal_locking&quot; rel=&quot;nofollow&quot;&gt;Tidally-locked planets&lt;/a&gt; aren't the greatest places for life. A decently-fast rotation can really help.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyway, Yang et al. came to this conclusion (as voiced in their opening sentence):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Planetary rotation rate is a key parameter in determining atmospheric circulation and hence the spatial pattern of clouds. Since clouds can exert a dominant control on planetary radiation balance, rotation rate could be critical for determining mean planetary climate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In other words, rotation helps clouds, and since clouds help govern the climate of the planet, a proper rotation rate can make the climate less extreme.&lt;/p&gt;&#xA;" OwnerUserId="1399" LastEditorUserId="20" LastEditDate="2016-02-20T00:40:33.610" LastActivityDate="2016-02-20T00:40:33.610" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3191" PostTypeId="2" ParentId="3167" CreationDate="2015-01-03T20:34:38.563" Score="3" Body="&lt;p&gt;Main danger to life near a volcano is not heat from the lava but volcanic gases.  Volcanic gases are typically very acidic, poisonous gases and can displace breathable air near lava flows.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://volcanoes.usgs.gov/hazards/gas/&quot; rel=&quot;nofollow&quot;&gt;http://volcanoes.usgs.gov/hazards/gas/&lt;/a&gt;&#xA;&lt;a href=&quot;http://en.wikipedia.org/wiki/Volcanic_gas&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/Volcanic_gas&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2015-01-03T20:34:38.563" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="3192" PostTypeId="2" ParentId="3186" CreationDate="2015-01-04T06:26:23.713" Score="6" Body="&lt;p&gt;David's answer is correct, but I wanted to elaborate a bit further.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth's axis is tilted about &lt;span class=&quot;math-container&quot;&gt;$23.5^\circ$&lt;/span&gt; from being perpendicular to the plane of its orbit (as David mentioned, 'obliquity' or 'axial tilt' is the name for this.) As a result of this tilt, at the solstices (the first day of winter or summer,) the sun is directly facing latitudes of either &lt;span class=&quot;math-container&quot;&gt;$23.5^\circ$&lt;/span&gt; North (the first day of summer in the Northern hemisphere) or &lt;span class=&quot;math-container&quot;&gt;$23.5^\circ$&lt;/span&gt; South (the first day of summer in the Southern hemisphere.) Areas between these two latitudes are known as the tropics, where the sun will be directly overhead at some point during the year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For latitudes farther away from the equator than the tropics, while the sun will never be directly overhead, the first day of summer in a given hemisphere will be the day in which the incident angle of the sun is the most shallow (i.e. the sun is as close as it will come to being directly overhead) and the first day of winter is the day in which the incident angle will be the most steep (i.e. the sun will be the farthest from passing directly overhead.) For example, at a latitude of &lt;span class=&quot;math-container&quot;&gt;$40^\circ$&lt;/span&gt;, on the first day of summer, the sun will be only &lt;span class=&quot;math-container&quot;&gt;$16.5^\circ$&lt;/span&gt; away from being directly overhead, while, on the first day of winter, it will be &lt;span class=&quot;math-container&quot;&gt;$63.5^\circ$&lt;/span&gt; away from being directly overhead. Solar power density for areas directly under the sun is about &lt;span class=&quot;math-container&quot;&gt;$1.4\ \mathrm{kW/m^2}$&lt;/span&gt;, so this gives us:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Solar power density at noon on the first day of summer at 40 degrees latitude:&lt;br&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$1.4\ \mathrm{kW/m^2} * \cos(16.5^\circ) = 1.4\ \mathrm{kW/m^2} * 0.959 = 1.34\ \mathrm{kW/m^2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And for winter:&lt;br&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$1.4\ \mathrm{kW/m^2} * \cos(63.5^\circ) = 1.4\ \mathrm{kW/m^2} * 0.446 = 0.62\ \mathrm{kW/m^2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, the sun will spend much more time above the horizon on the first day of summer than on the first day of winter, again, due to the axial tilt of Earth. The combination of these two effects results in the dramatic difference in average solar heating observed between summer and winter in latitudes that are distant from the equator. This local difference in solar heating through the year is the dominant factor in determining seasons as the Earth orbits the sun, not the comparatively minor differences in actual distance between the Earth and the sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a graphical comparison, take a look at the solar power density measurement graphs on these pages, from a weather station located about &lt;span class=&quot;math-container&quot;&gt;$36.2^\circ$&lt;/span&gt; North:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.wunderground.com/personal-weather-station/dashboard?ID=KTNCOOKE16#history/s20141220/e20141220/mdaily&quot; rel=&quot;nofollow noreferrer&quot;&gt;December 20, 2014&lt;/a&gt; (a day before the solstice because the actual solstice was cloudy)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.wunderground.com/personal-weather-station/dashboard?ID=KTNCOOKE16#history/s20140622/e20140622/mdaily&quot; rel=&quot;nofollow noreferrer&quot;&gt;June 22, 2014&lt;/a&gt; (again, a day off the solstice, due to clouds on the solstice.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would copy the graphs into this post, but they're copyrighted by that site, so you'll have to visit the links and scroll down to the power density graphs. Note that apparent noise in the graphs is primarily due to clouds briefly passing over.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The areas under these curves (i.e. total solar energy per unit area per day) are roughly &lt;span class=&quot;math-container&quot;&gt;$2.4\ \mathrm{kW\ hr/m^2}$&lt;/span&gt; for the beginning of winter and &lt;span class=&quot;math-container&quot;&gt;$7.3\ \mathrm{kW\ hr/m^2}$&lt;/span&gt; for the beginning of summer. At least, that's about what they would have been had there been no clouds in the way.&lt;/p&gt;&#xA;" OwnerUserId="1099" LastEditorUserId="1099" LastEditDate="2019-02-18T21:52:45.013" LastActivityDate="2019-02-18T21:52:45.013" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="3193" PostTypeId="1" AcceptedAnswerId="4421" CreationDate="2015-01-04T20:49:20.857" Score="23" ViewCount="932" Body="&lt;p&gt;There are parts of the U.S. where, on average, the coldest day of the year comes before December 21st. [&lt;a href=&quot;http://www.ncdc.noaa.gov/news/when-to-expect-coldest-day-of-year&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/jb44J.jpg&quot; alt=&quot;Coldest day of the year&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can this be? Why would temperatures start rising again even while days are still growing shorter?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(I would have assumed that daily temperatures should, in general, always lag behind daily insolation, with some sort of &lt;a href=&quot;http://en.wikipedia.org/wiki/Hysteresis&quot; rel=&quot;noreferrer&quot;&gt;hysteresis&lt;/a&gt; relationship.)&lt;/p&gt;&#xA;" OwnerUserId="1406" LastEditorUserId="269" LastEditDate="2015-01-05T13:56:20.163" LastActivityDate="2015-02-18T18:26:04.567" Title="How can the average coldest day of the year be before the winter solstice?" Tags="|meteorology|climate|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3194" PostTypeId="1" CreationDate="2015-01-04T23:24:47.823" Score="4" ViewCount="616" Body="&lt;p&gt;Anthropogenic carbon or black carbon (BC), particularly soot, is a product of many human activities, a major one being incomplete combustion of hydrocarbons. The occurrences of soot are mainly in cities, although there have been observations of these aerosols occurring in sparsely inhabited, yet environmentally sensitive areas, such as polar ice caps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As such, it is a critical component of atmospheric aerosols affecting the Earth's atmospheric radiation budget.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How much do anthropogenic carbon aerosols affect the atmospheric radiation budget?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2015-01-08T05:10:47.443" Title="How much do anthropogenic carbon aerosols (soot) affect the atmospheric radiation budget?" Tags="|atmosphere|pollution|atmosphere-modelling|atmospheric-radiation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3195" PostTypeId="2" ParentId="3194" CreationDate="2015-01-04T23:24:47.823" Score="3" Body="&lt;p&gt;&lt;em&gt;For the purposes of the answer, anthropogenic carbon sources, will be referred to as BC (black carbon).&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The effects of BC on atmospheric radiative forcing has come under considerable scrutiny in the past few years, several studies have sought to determine exactly the effect of this aerosol has on the Earth's radiation budget.  A major study was performed by Bond et al. (2013), in the article &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/jgrd.50171/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bounding the role of black carbon in the climate system: A scientific assessment&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A summary of the emissions and effects are shown in the image below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/VteeG.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Caption: Schematic overview of the primary black-carbon emission sources and the processes that control the distribution of black carbon in the atmosphere and determine its role in the climate system. (Bond et al. 2013)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Their findings was that the total direct forcing of BC, independent of co-emitted aerosol species and including all sources (direct emissions, pre-industrial background, cryosphere and clouds) is &lt;strong&gt;+1.1 Wm&lt;sup&gt;-2&lt;/sup&gt;&lt;/strong&gt; with an uncertainty range of +0.08 Wm&lt;sup&gt;-2&lt;/sup&gt; to +2.1 Wm&lt;sup&gt;-2&lt;/sup&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This places BC itself as the 2nd most important anthropogenic emission, behind $\ce{CO2}$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, when the total radiative effects of BC with co-emitted aerosols, including organic carbon sources are taken into consideration, there is a slight cooling effect, with the total direct radiative forcing of &lt;strong&gt;-0.06 Wm&lt;sup&gt;-2&lt;/sup&gt;&lt;/strong&gt;, with a greater uncertainty range of -1.45 Wm&lt;sup&gt;-2&lt;/sup&gt; to +1.29 Wm&lt;sup&gt;-2&lt;/sup&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/X4Lir.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bond et al. 2013.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A major source for the uncertainties is described by Bond et al. (2013) as being due to a lack of knowledge of how black carbon and co-emitted species interact with clouds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;In summary&lt;/strong&gt;, from the research that Bond et al. (2013) performed, the presence of black carbon itself causes a significant positive radiative forcing, but when considered with its co-emitted aerosols, there is a slight negative radiative forcing.  However, the uncertainties calculated demonstrate that there are still mechanisms that are not completely understood.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Image permissions (from the linked article): This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="200" LastEditDate="2015-01-08T05:10:47.443" LastActivityDate="2015-01-08T05:10:47.443" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3196" PostTypeId="1" AcceptedAnswerId="3204" CreationDate="2015-01-04T23:36:20.947" Score="14" ViewCount="400" Body="&lt;p&gt;Say we have a model that describes a physical or dynamical system, for example, a hydrological model. If the model results do not match the measurements of the quantity being simulated, i.e. the model validation fails, is there any value in using the model for some other case or application?  &lt;/p&gt;&#xA;" OwnerUserId="1408" LastEditorUserId="192" LastEditDate="2015-01-05T23:00:13.650" LastActivityDate="2016-10-14T03:08:34.700" Title="Is there value in using a model that fails at validation against measurements?" Tags="|models|" AnswerCount="6" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="3198" PostTypeId="2" ParentId="3196" CreationDate="2015-01-05T23:42:55.903" Score="8" Body="&lt;p&gt;Yes there is value.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;1)Often times we use models to check our own understanding of a process.  If the model is built with all known factors included, it might still fail to produce results that can be verified with measurements. When the model is unable to reproduce a phenomenon, the test case can be used to assess what parts of the model need further development.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2)Sometimes systems are too complicated to model accurately (or perhaps there are too many unknowns in the initial or boundary conditions).  Although the model might fail to reproduce absolute values that are measured, it might still be able to produce realistic dynamic variance.  So, the model is still useful for studying the relationships between the dynamic processes that are involved.  This is sometimes how we find secondary effects that are not typically direct outcomes of the model processes.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2015-01-05T23:42:55.903" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3199" PostTypeId="2" ParentId="3196" CreationDate="2015-01-06T00:39:46.287" Score="11" Body="&lt;p&gt;The late George Box famously said:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;All models are wrong. Some models are useful&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;All models are wrong.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's important.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;All&lt;/em&gt; models are wrong.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In any real-world system that we're interested in, the only accurate model of the system, is the system itself. Anything else, any simplification, gives wrong answers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some models are useful.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's important, too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some models help us structure our discussions of the uncertainties (H/T Prof Neil Strachan)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some models allow us to test &quot;what if&quot; scenarios, and look at what the relative changes might be. Now, in the real world, exogenous influences that the model can't account for, would mean that the actual outcomes would be different: but if the model gives a near-enough account of the scale of relative changes, we can still make informed judgements on the basis of the models. Even when it involves pesky things such as turbulence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some models give us insights into emergent properties of systems: a lot of the really interesting problems are emergent properties that aren't necessarily obvious from just looking at the basic rules of the system, and any insights we can gain are valuable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some models allow us to do experiments on systems that we couldn't possibly experiment on. And although we know the models are wrong, they can at least give us an indication of the range of possible outcomes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's not to defend the use of bad models to do bad work. There's far too much of that in my field, and I do not like it. As Simon W says, it is possible to test models to see if they are suitable for a particular purpose. To continue using a model &lt;em&gt;for a purpose where it is known to be inapplicable&lt;/em&gt;, is charlatanry, not academia.&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="100" LastEditDate="2015-01-06T14:25:32.600" LastActivityDate="2015-01-06T14:25:32.600" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="3200" PostTypeId="2" ParentId="3196" CreationDate="2015-01-06T09:02:26.853" Score="6" Body="&lt;p&gt;Since there are already two answers discussing possible merits in further analysis let me just add the other side of the coin; it could also be prudent to see the simulation as a failure and not analyse it any further.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That could be the case if it's state of the art that similar simulations reproduce these experimental values you were mentioning and if these simulation can reproduce the values you want to look at as well. &#xA;In that case, it only makes sense to try to find out why you can't reproduce your experimental test values. If you do not want to spend much time in developing the model, then drop it altogether; no one will trust your results.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Trust is, in my opinion, the crucial point here. As mentioned in the previous answers it is not uncommon for simulations to give only (poor) estimates of experimental results. But it is all important in these cases that you can scrutinize why you still trust the results you want to get out of it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To be honest, I do read your question that way that you have no good reason to be confident in further results. If that is the case my advice would be to step back and first think about whether you can trust them. To do that no general answer will help you; it depends too strongly on your system and what the state of the art is for these kind of simulations.&lt;/p&gt;&#xA;" OwnerUserId="526" LastActivityDate="2015-01-06T09:02:26.853" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3201" PostTypeId="1" AcceptedAnswerId="4268" CreationDate="2015-01-06T10:09:05.463" Score="11" ViewCount="290" Body="&lt;p&gt;The Antarctic Circumpolar Current (ACC) is the continuous oceanic current that encircles the Antarctic continent, as is often explained in the literature as being the cause of the onset of glaciation in Antarctica.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, a study in 2013, in the article &lt;a href=&quot;http://geology.gsapubs.org/content/early/2013/07/10/G34352.1.abstract&quot;&gt;A potential barrier to deep Antarctic circumpolar flow until the late Miocene?&lt;/a&gt;, suggest that the ACC did not fully develop until the late Miocene, due to the current being blocked by a volcanic arc in the early Drake Passage, and that the ACC importance was not in the global cooling on the Eocene-Oligocene boundary, but in the intensification in the late Miocene of the glaciation of Antarctica.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is there conclusive evidence for the Antarctic Circumpolar Current developing after the glaciation of Antarctica?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-01-06T10:16:18.930" LastActivityDate="2015-01-15T14:15:22.960" Title="Is there conclusive evidence for the Antarctic Circumpolar Current developing after the glaciation of Antarctica?" Tags="|earth-history|ocean-currents|antarctic|glaciation|" AnswerCount="1" CommentCount="3" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3202" PostTypeId="1" CreationDate="2015-01-06T11:41:50.597" Score="13" ViewCount="795" Body="&lt;p&gt;The West Antarctic Rift exists between the Trans-Antarctic Mountains and Marie Byrd Land (see map below for reference)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/GGWki.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image source: NASA&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rift system is believed to be like the &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2745/is-there-evidence-to-delineate-where-a-southern-extension-of-the-east-african-ri/2922#2922&quot;&gt;East African Rift&lt;/a&gt;, consisting of several interconnected rifts, many are believed to be inactive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the &lt;a href=&quot;http://en.wikipedia.org/wiki/West_Antarctic_Rift&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia article&lt;/a&gt; vaguely mentions:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;it is now known that West Antarctica is moving away from the East Antarctic Craton in a north/northeasterly direction (approximately in the direction of the South Georgia Islands) at a rate of about 2 mm per year or 500,000 years per kilometre.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What evidence is there for active rifting in West Antarctica?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="2470" LastEditDate="2021-07-06T07:26:52.990" LastActivityDate="2021-07-06T07:26:52.990" Title="Active rifting in Antarctica?" Tags="|plate-tectonics|antarctica|continental-rifting|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3203" PostTypeId="2" ParentId="3196" CreationDate="2015-01-06T13:41:14.310" Score="7" Body="&lt;p&gt;A slightly different slant:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As energynumbers has pointed out, all models are wrong in one way or another. A fully accurate model of reality would be as complex as reality, so some simplification is always needed. This means that there cannot be any useful model whose predictions in every way are perfectly accurate (except possibly by accident).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Validating a model, therefore, is not a process for saying &quot;Is this model correct&quot; with a yes/no answer. Rather, it should be about,&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Deciding criteria the model must fulfill to be useful &lt;em&gt;for a given purpose&lt;/em&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Assessing whether it fulfills those criteria.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;If the model fails validation for one application, it may still be useful for another.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some examples of different validation criteria, taking a regional ocean model as an example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One obvious choice is whether the predictions of current speeds or of water levels is most important. Even after selecting one of these, the way in which the predictions are assessed may vary. A reasonable default might be to assess the fit at every time point between measured and observed water levels in a number of places, and accept the model if measurements such as bias and RMSE are below defined thresholds. However, here are two examples of specific scenarios that justify different approaches:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;NOAA runs models whose primary application is the production of depth information for navigational aids. The critical statistic for them is not the general accuracy of their models, but the frequency with which the model overpredicts the water level - as this form of error could result in vessels running aground. [1]&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Vested et al (1995) [2] give an example of a storm surge model that would provide flood warnings. It was tested not for the accuracy of all of its water level predictions, but for the accuracy of its predictions of &lt;em&gt;peak&lt;/em&gt; water levels, as those are what would matter in operation.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;[1] NOAA &lt;a href=&quot;http://www.nauticalcharts.noaa.gov/csdl/docs/RD_standards_Hess_etal.pdf&quot; rel=&quot;nofollow&quot;&gt;NOS STANDARDS FOR EVALUATING OPERATIONAL NOWCAST AND FORECAST HYDRODYNAMIC MODEL SYSTEMS Silver Spring, Maryland October 2003 noaa National Oceanic and Atmospheric Administration U.S.&lt;/a&gt;,  NOAA Technical Report NOS CS 17, Oct. 2003&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[2] H. J. Vested, J. W. Nielsen, H. R. Jensen, and K. B. Kristensen, “Skill Assessment of an Operational Hydrodynamic Forecast System for the North Sea and Danish Belts,” in Quantitative Skill Assessment for Coastal Ocean Models, vol. 47, D. R. Lynch and A. M. Davies, Eds. Washington DC: American Geophysical Union, 1995, pp. 373–396.&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="6093" LastEditDate="2016-10-13T13:26:07.090" LastActivityDate="2016-10-13T13:26:07.090" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3204" PostTypeId="2" ParentId="3196" CreationDate="2015-01-06T18:49:24.013" Score="9" Body="&lt;p&gt;The answer depends very much on where the model fails. If it is very accurate in some regimes but very inaccurate in others, that model can still be used in those regimes where it is known to be very accurate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good example is Newtonian mechanics. Newtonian mechanics now known to be wrong (sometimes very wrong) as a universal model. Using Newtonian principles to build a collider that studies quantum events that result from relativistic collisions doesn't make much sense. On the other hand, Newtonian mechanics works very well in the ordinary, everyday world of earthly events. We still build bridges using Newtonian mechanics. It would be downright silly to invoke general relativity in bridge design.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What if the model doesn't work anywhere, or if the interval over which it does yield somewhat reasonable results is vanishingly small? In that case, the model isn't very good. A model needs to have some space over which the results are acceptable to have even limited applicability.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-01-06T18:49:24.013" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3205" PostTypeId="1" AcceptedAnswerId="3206" CreationDate="2015-01-06T18:53:11.460" Score="10" ViewCount="150" Body="&lt;p&gt;The mechanism for the formation of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Gamburtsev_Mountain_Range&quot; rel=&quot;nofollow&quot;&gt;Gamburtsev Subglacial Mountains&lt;/a&gt; in East Antarctica seems to be a combination of old volcanism and Cretaceous rifting (&lt;a href=&quot;http://dx.doi.org/10.1038/nature10566&quot; rel=&quot;nofollow&quot;&gt;Ferraccioli et al., 2011&lt;/a&gt;). While the modeling results seem to match the available geophysical observations, have there been any dating studies that looked at age through the analysis of rock samples?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="2470" LastEditDate="2021-07-06T07:23:16.917" LastActivityDate="2021-07-06T07:23:16.917" Title="What is the age of the Gamburtsev Mountains?" Tags="|mountains|geomorphology|antarctica|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="3206" PostTypeId="2" ParentId="3205" CreationDate="2015-01-06T21:30:28.750" Score="10" Body="&lt;p&gt;The &lt;a href=&quot;http://www.ldeo.columbia.edu/res/pi/gambit/Gamburtsevs.html&quot; rel=&quot;nofollow&quot;&gt;Lamont-Doherty Earth Observatory&lt;/a&gt; describes the Gamburtsev Subglacial Mountains (GSM) as being like:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;opening the door of an Egyptian pyramid and finding an astronaut inside.  There is no good reason for an astronaut to be inside an Egyptian pyramid just as there is no good reason for a major mountain range in the middle of East Antarctica.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Despite being buried under a considerable amount of ice and observed to have had slow erosion rates since at least the Permian (Cox et al. 2010), accessible detrital material has been determined to have been deposited as fluvio-deltaic deposits in Prydz Bay (Cox et al. 2010; Flierdt et al. 2008).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\ce{U-Pb}$ dating of dertital zircons and $\ce{^40Ar/^39Ar}%edit$ dating of detrital hornblendes age them as ~530 Ma and ~519 Ma respectively, with no evidence of any yonger volcanic contributions (Flierdt et al. 2008).  These dates led Cox et al. (2010) to postulate that the GSM formed during the &lt;a href=&quot;http://www.utdallas.edu/~rjstern/pdfs/PanAfricanOrogeny.pdf&quot; rel=&quot;nofollow&quot;&gt;Pan-African Orogeny&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Veevers and Saeed (2013) suggest that detrital zircons found in the Ellsworth Land–Antarctic Peninsula–Weddell Sea–Dronning Maud Land sector of ages 1.4-1.7 Ga, 1.9-2.1 Ga and 3-3.35 Ga possibly have their provenance from the GSM.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;In summary&lt;/strong&gt;, in the absence of direct measurements of GSM petrology, detrital material from pre-glacial erosion has suggested that the youngest tectonothermal evidence is for a Cambrian age of the GSM.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cox et al. 2010 &lt;a href=&quot;http://authors.library.caltech.edu/21429/1/Cox2010p12239Geophys_Res_Lett.pdf&quot; rel=&quot;nofollow&quot;&gt;Extremely low long-term erosion rates around the Gamburtsev&#xA;Mountains in interior East Antarctica&lt;/a&gt;, &lt;em&gt;Geophysical Research Letters&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Flierdt et al. 2008 &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2008GL035564/full&quot; rel=&quot;nofollow&quot;&gt;Evidence against a young volcanic origin of the Gamburtsev Subglacial Mountains, Antarctica&lt;/a&gt; &lt;em&gt;Geophysical Research Letters&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Veevers and Saeed, 2013 &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S1342937X12001864&quot; rel=&quot;nofollow&quot;&gt;Age and composition of Antarctic sub-glacial bedrock reflected by detrital zircons, erratics, and recycled microfossils in the Ellsworth Land–Antarctic Peninsula–Weddell Sea–Dronning Maud Land sector (240°E–0°–015°E)&lt;/a&gt; &lt;em&gt;Gondwana Research&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="2665" LastEditDate="2016-07-21T04:57:57.463" LastActivityDate="2016-07-21T04:57:57.463" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4204" PostTypeId="1" AcceptedAnswerId="4214" CreationDate="2015-01-07T14:39:17.043" Score="6" ViewCount="969" Body="&lt;p&gt;Hydrothermal vents are commonly found near active volcanic areas and provide for a rich and complex environment for many biological organisms (archaea, bacteria, tube worms...). Many new hydrothermal vent systems are being discovered and many more are likely to be discovered in the future. My questions are which hydrothermal vent system is currently considered to be the tallest? What contribute to make that system larger? How old is the vent system? Are there any peculiar organisms associated with the system that haven't been found anywhere else?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorDisplayName="user889" LastEditDate="2015-03-28T02:02:51.903" LastActivityDate="2015-03-28T02:02:51.903" Title="What are the tallest hydrothermal vents in the world?" Tags="|ocean|volcanology|geothermal-heat|hydrothermal-vents|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4205" PostTypeId="1" CreationDate="2015-01-07T14:46:58.123" Score="6" ViewCount="1153" Body="&lt;p&gt;Hydrothermal vents are common in areas subject to volcanic activity at the bottom of Earth's oceans. Meanwhile, hydrothermal vents are believed to exist on Jupiter's moon Europa and maybe in other moons of the Solar System. Vents on Earth are beginning to be understood and the complex ecosystems associated with them provide many new and fascinating discoveries. My question is what are differences between vents in the two systems? &lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-01-08T02:04:09.287" Title="Differences between hydrothermal vents on Earth and Europa" Tags="|ocean|planetary-science|earth-system|hydrothermal-vents|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4206" PostTypeId="2" ParentId="3131" CreationDate="2015-01-07T16:44:30.457" Score="9" Body="&lt;p&gt;This is no trivial search and as I was not able to source any information from the MIT website - this is a part answer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any Internet search for the term Geoalchemy brings up the &lt;a href=&quot;http://geoalchemy-2.readthedocs.org/en/latest/&quot; rel=&quot;nofollow noreferrer&quot;&gt;a support library for SQLAlchemy, that adds support for spatial databases.&lt;/a&gt;  (Stack Overflow has a tags for &lt;a href=&quot;https://stackoverflow.com/questions/tagged/geoalchemy&quot;&gt;geoalchemy&lt;/a&gt; and &lt;a href=&quot;https://stackoverflow.com/questions/tagged/geoalchemy2&quot;&gt;geoalchemy2&lt;/a&gt;)- none of which is really related to why the department was named so, interestingly, the program has a MIT licence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some examples of the usage of the term extend to recent times:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;In 2013, the &lt;a href=&quot;http://www.ottawageotechnicalgroup.com/archives/OGG-Announcement-2013-10-08.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ottawa Geotechnical Group had a lecture tour presentation&lt;/a&gt; that hints at a definition:&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Geo-Alchemy: Turning Sand into Sandstone and other Microbiological and&#xA;   Bio-Inspired Ground Improvement Technologies.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The abstract for the article &lt;a href=&quot;http://www.searchanddiscovery.com/abstracts/html/2001/annual/abstracts/0167.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Evolution of Knowledge and Ideas in Petroleum Geochemistry - From &quot;GeoAlchemy&quot; to Petroleum Systems Analysis and Beyond&lt;/a&gt; (Creaney and Isakson, 2001) indicate that petroleum geochemistry was developed out of earlier disciplines that were geological and chemistry based.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Earlier, in a 1984 article &lt;a href=&quot;http://www.mosaicsciencemagazine.org/pdf/m15_06_84_04.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Windows to the Earth&lt;/a&gt; (Comrie), has on page 35 a subheading 'Geoalchemy', in it the author focuses on the isotopic geochemistry of volcanics.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Much earlier, in the time of Isaac Newton, the article &lt;a href=&quot;http://historyofgeology.fieldofscience.com/2013/03/newtons-alchemy-and-early-geochemistry.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Newton's Alchemy and early Geochemistry&lt;/a&gt; describes how he and other naturalists of the day saw the crystalisation of saltpeter (potassium nitrate)  as a model for mineral growth and ore genesis.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;It seems from these examples, past and present, that the term 'geoalchemy' stems from the terms geology and alchemy and was (and in some cases, still is) used as a fancy way of saying 'geochemistry'. &lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditDate="2017-05-23T12:41:54.877" LastActivityDate="2015-01-07T16:44:30.457" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4207" PostTypeId="2" ParentId="3193" CreationDate="2015-01-07T19:14:19.247" Score="3" Body="&lt;p&gt;Climate is a very complex subject and really not my area of expertise but there are a couple of items to consider.  You are only looking at a small subset of the northern hemisphere and you have to consider how the weather patterns change over the seasons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You will note that on your map that the Western States show earlier colder periods.  I suspect that this is primary influenced by the changes in the weather pattern developments over the Pacific ocean as winter approaches.  The Pacific ocean temperature doesn't vary much over the year, as winter approaches the temperature difference between the air and the water is more pronounced.  This leads to increasing stronger (deeper) low pressure cells over the Pacific.  As winter progresses these storms continue to develop and pass over the continent effectively transferring more heat from the Pacific to the continent.  As the temperature difference between the atmosphere and the ocean increases these winters storms become stronger.  In the area I live in (Vancouver Island) December can often be cold because of Artic highs influencing our weather but once winter has been established we often have a lot of cloud cover, warm weather, and rain.  Sometimes we get very warm weather from Hawaii, this is called the Pineapple Express &lt;a href=&quot;http://en.wikipedia.org/wiki/Pineapple_Express&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/Pineapple_Express.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In summary I suspect that the weather pattern you have observed is primarily driven by the changes in the weather patterns over the Pacific Ocean caused by the generally lowering of the atmospheric temperature in the Northern Hemisphere.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2015-01-07T19:14:19.247" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4208" PostTypeId="2" ParentId="3189" CreationDate="2015-01-07T19:31:11.527" Score="3" Body="&lt;p&gt;They form due to strong convective forces, coriolis effects, local wind and weather, and local topography.  The fire effectively creates an intense localized low pressure cell due to the heating of the air which can behave similar to any low pressure system.  I haven't seen one on flat terrain like your picture shows but when performing slash burns for silviculture purposes you can have very large tornados form along ridges as the fire burns uphill.  These tornados can extend outside the fire zone under the right conditions but generally die out soon once removed from the source of heat.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2015-01-07T19:31:11.527" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4209" PostTypeId="1" AcceptedAnswerId="4210" CreationDate="2015-01-07T19:42:41.703" Score="8" ViewCount="1214" Body="&lt;p&gt;I have found a wealth of information using Harmonic Constituents to calculate tide levels.  H(t) = Amplitude * cos ( t * harmonicSpeed + phase lag).  Yet when I try to apply this to constituents from the NOAA the results never match the tables produced.  I have since found that the NOAA constituents require an additional term, the Equilibrium value with the resulting constituent function looking more like &lt;/p&gt;&#xA;&#xA;&lt;p&gt;H(t) = Amplitude * cos ( t * harmonicSpeed + EquilibriumValue + phase lag). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am looking for any hints on how this Equilibrium value is calculated or derived.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Addendum:&#xA;The constituents are found here, this for San Diego, Ca&#xA;&lt;a href=&quot;http://tidesandcurrents.noaa.gov/harcon.html?id=9410170&quot; rel=&quot;nofollow&quot;&gt;Constituents for San Diego&lt;/a&gt;.  Sorry cannot find the source of the Equilibrium value but will when I get home from work.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastEditorDisplayName="user824" LastEditDate="2015-01-07T22:41:37.520" LastActivityDate="2015-01-08T03:38:20.640" Title="How to Calculate the Equilibrum Function for use in Tide Calculations using Harmonic Constituents" Tags="|ocean|oceanography|ocean-currents|tides|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4210" PostTypeId="2" ParentId="4209" CreationDate="2015-01-07T22:29:37.593" Score="3" Body="&lt;p&gt;The equilibrium tide is a theoretical concept developed by Newton in the 17th century that considers only the gravitational pull by the Moon and the Sun and the centrifugal forces, with no inertia, no friction and no land masses. From the NOAA definitions: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;equilibrium theory — A model under which it is assumed that the waters covering the face of the Earth instantly respond to the tide-producing forces of the Moon and Sun to form a surface of equilibrium under the action of these forces. The model disregards friction, inertia, and the irregular distribution of the land masses of the Earth. The theoretical tide formed under these conditions is known as the equilibrium tide.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Lets consider as a first cut the two tide producing forces associated with just the Moon and Earth systems. The two are the centrifugal force of Earth from the center of mass of the Moon-Earth system and the gravitational attraction due to the Moon. For the point closest to the Moon:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ Force = \frac {GM_1M_2}{(R-r)^2}  - \frac{GM_1M_2}{R^2} $$ where R is the distance between Earth and Moon and r is Earth's radius. It gets a bit more complex for other points on the surface because instead of R you have to use $$R\pm r cos(lat) $$ for the gravitational force.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ultimately, it comes down to a set of horizontal forces that tend to concentrate water in two theoretical points: one, the closest to the Moon and two, the farthest from the Moon. An equilibrium state would be reached, called &lt;strong&gt;equilibrium tide&lt;/strong&gt;, that results in an ellipsoid with its two bulges directed toward and away from the Moon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In practice, this equilibrium ellipsoid does not develop because of the rotation of Earth, the Coriolis acceleration and the fact that the tidal wave feels the ocean bottom and it is subject to friction. Going beyond the equilibrium theory of the tide, the dynamic theory of tides (developed by Euler, Laplace and Bernoulli) includes all these concepts (friction, inertia, Coriolis, land masses,...) and provides a better approximation to the observed tides. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My recommendation to understand tidal constituents is to use some decent tidal harmonic analysis package like &lt;a href=&quot;http://dx.doi.org/10.1016/S0098-3004(02)00013-4&quot; rel=&quot;nofollow&quot;&gt;t_tide&lt;/a&gt; for Matlab, which is likely to be the tool that NOAA is using to generate their harmonic constituents in the first place. If you really want to get into the details, then the best option is to go to the still likely best source available. That will the 1973 book &quot;The Analysis of Tides&quot; by G. Godin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Pawlowicz, R., B. Beardsley, and S. Lentz, &quot;Classical Tidal Harmonic Analysis Including Error Estimates in MATLAB using &lt;a href=&quot;http://dx.doi.org/10.1016/S0098-3004(02)00013-4&quot; rel=&quot;nofollow&quot;&gt;t_tide&lt;/a&gt;&quot;, Computers and Geosciences, 28, 929-937 (2002).&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Godin, G. (1973). The analysis of tides., by Godin, G.. Liverpool (UK): Liverpool University Press, 264 p.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2015-01-08T03:38:20.640" LastActivityDate="2015-01-08T03:38:20.640" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4211" PostTypeId="1" CreationDate="2015-01-08T00:08:21.810" Score="8" ViewCount="135" Body="&lt;p&gt;In the context of the land surface, the ground absorbs heat from radiation (also some times from precipitation and advection), and releases heat through evapotranspiration, advection and radiation, and run-off. If it were a closed system, you would expect the net heat loss/gain to be zero (at least on a reasonably long time scale, that irons out daily and seasonal cycles, and noise). However, there is also heat from the mantle to consider, and also heat conduction to the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there other avenues for heat loss or gain from the soil? Are any of these significant in a climatological context? Or should the total heat flux into (or out of) the ground from the atmosphere be equal to zero (or close enough for practical purposes, over time scales longer than a year)?&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="56" LastEditDate="2015-01-08T13:34:29.463" LastActivityDate="2015-01-08T17:35:56.603" Title="Should total ground heat flux be 0?" Tags="|climatology|land-surface|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4212" PostTypeId="2" ParentId="4205" CreationDate="2015-01-08T02:04:09.287" Score="4" Body="&lt;p&gt;At the moment, the question is unanswerable, because nobody knows if the vents exist - or even if there is an ocean under Europa's icy exterior (although the idea is reasonably well-accepted). At the moment, they're hypothetical, and until a mission is sent to Europa to observe the depths of its oceans, we won't know much about them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Well, there actually is one difference. On Earth, hydrothermal vents are the byproducts of tectonic activity. They occur near where tectonic plates meet - for example, in the Mid-Atlantic Ridge, or the Pacific Ring of Fire. On Europa, however, the source of the vents is thought to be tidal interactions with Jupiter, which provide enough heat to keep the ocean from freezing solid, like the moon's exterior.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is one interesting difference regarding the impacts of vents, described in part of &lt;a href=&quot;http://www-paoc.mit.edu/paoc/papers/europa_plume.pdf&quot; rel=&quot;nofollow&quot;&gt;this paper&lt;/a&gt; (starting at the bottom of page 7, then jumping in more detail to page 10), which is that Earth's oceans are stratified (i.e composed of distinct layers, stemming from effects of heating, cooling, and convection), whereas Europa's ocean may be unstratified and uniform. On page 10, the authors explain this by saying:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Earth's ocean is stratified because it is both heated and cooled at different locations along the upper surface. Water cooled at the poles slides beneath warm tropical water, forming stable stratification. If the dominant source of buoyancy in Europa's ocean is heat input at the base, the situation is more reminiscent of a pot of water on a stove, or of convection in the Earth's liquid core. The fluid should be convectively unstable everywhere, and stable stratification should not occur.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The authors say that they can apply this unstratified model to plumes from vents and therefore better explain ocean dynamics on Europa.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Sources:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://oceanservice.noaa.gov/facts/vents.html&quot; rel=&quot;nofollow&quot;&gt;National Oceanic and Atmospheric Administration&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.whoi.edu/main/topic/hydrothermal-vents&quot; rel=&quot;nofollow&quot;&gt;Woods Hole Oceanographic Institution&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;&lt;a href=&quot;http://www-paoc.mit.edu/paoc/papers/europa_plume.pdf&quot; rel=&quot;nofollow&quot;&gt;Hydrothermal Plume Dynamics on Europa: Implications for Chaos Formation&quot; by Goodman et al.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1399" LastActivityDate="2015-01-08T02:04:09.287" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4213" PostTypeId="1" CreationDate="2015-01-08T03:12:27.040" Score="10" ViewCount="444" Body="&lt;p&gt;Associated with the &lt;a href=&quot;http://www.volcanodiscovery.com/nw_eifuku.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NW Eifuku volcano&lt;/a&gt;, a small submarine volcano in Japan's Volcano Island chain in the Pacific Ocean is a carbon dioxide rich hydrothermal vents called &lt;strong&gt;white smokers&lt;/strong&gt; by NOAA (see image below):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/nxxJ8.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image source: &lt;a href=&quot;http://oceanexplorer.noaa.gov/explorations/04fire/logs/april12/media/champagne_vent.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA Ocean Explorer&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In research reported in the Science Daily article &lt;a href=&quot;http://www.sciencedaily.com/releases/2005/01/050104114942.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scientists Discover Liquid Carbon Dioxide 'Champagne' Bubbles At Hydrothermal Vent&lt;/a&gt; (NOAA, 2005), it has been determined by measurements of the hydrothermal fluids that there appeared to be from 2 vent fluids:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;a hot (&gt;100 C &gt;212 F) fluid that has been found to contain about 60 L of gaseous carbon dioxide per kilogram.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;alongside the hot vent, the researchers found that there were cold droplets of about 90% liquid carbon dioxide.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;These droplet give the vent its name, as it is 'effervescent' like champagne.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is the geochemical origin of the carbon dioxide associated with the 'white smokers' of the Champagne Vent?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-03-28T13:57:17.263" LastActivityDate="2015-03-29T06:44:38.470" Title="What is the geochemical origin of carbon dioxide with the 'white smokers' of the Champagne Vent?" Tags="|ocean|volcanology|geochemistry|geothermal-heat|hydrothermal-vents|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4214" PostTypeId="2" ParentId="4204" CreationDate="2015-01-08T05:10:09.317" Score="6" Body="&lt;p&gt;The tallest hydrothermal vent is the &lt;strong&gt;60 m (180 ft) tall carbonate Poseidon vent&lt;/strong&gt;, among the Lost City hydrothermal vent system on top of the ~4km high Atlantis Massif, located 20 km west of the Mid-Atlantic Ridge at 30°N.  The vents emit pH 9-11 metal-poor fluids at about 90°C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The composition of the hydrothermal vents are aragonite, calcite (both polymorphs of calcium carbonate, $\ce{CaCO3}$), and brucite ($\ce{Mg(OH)2}$) giving the white colour of the vents, the pinnacle of the Poseidon vent is shown below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ooe5r.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://oceanexplorer.noaa.gov/explorations/05lostcity/background/chimney/chimney.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA Ocean Explorer&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Lost City hydrothermal vents are discussed in detail in the University of Washington's &lt;a href=&quot;http://www.lostcity.washington.edu/story/About&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lost City Research&lt;/a&gt; and NOAA's &lt;a href=&quot;http://oceanexplorer.noaa.gov/explorations/05lostcity/background/chimney/chimney.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Formation of Carbonate Chimneys at the Lost City Hydrothermal Field&lt;/a&gt; page, from the websites, in answer to your questions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Age:&lt;/strong&gt; presumed to be over 30,000 years old.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What contributes to its height:&lt;/strong&gt; Asides from the age of the vents, which allows the vents to build up. The vents are formed on a base of thick fossiliferous pelagic limestone, which form an impervious lid trapping the hydrothermal fluids and geothermal heat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This limestone overlies a sedimentary breccia, which overlies fractured and faulted basement of highly deformed serpentites and exposed Mg-rich mantle rocks (peridotites).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Biomass:&lt;/strong&gt; It is believed that 58% of the fauna are endemic to the Lost City environment, including the Lost City Methanosarcinales inhabiting the anoxic interior zones of the vent, which are an example of &lt;a href=&quot;http://aem.asm.org/content/72/9/6257.abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;Methane- and Sulfur-Metabolizing Microbial Communities Dominate the Lost City Hydrothermal Field Ecosystem&lt;/a&gt; (Brazelton et al. 2006).  Observations suggest that $\ce{CH4}$ and $\ce{S}$ cycling dominate the ecological processes in the Lost City vent environment.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-01-08T09:43:48.127" LastActivityDate="2015-01-08T09:43:48.127" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4215" PostTypeId="2" ParentId="2789" CreationDate="2015-01-08T06:05:50.640" Score="14" Body="&lt;p&gt;Your question is fairly broad, and slightly vague so I don't know if I will be able to answer it in one go. If you would like any clarification, let me know.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;How are predictions made?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The basic process generally used for probabilistic forecasting of the global climate is something like:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Take one or more general circulation models (GCMs), and run multiple simulations over the projection period.&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;GCMs are models that attempt to replicate the physics of the climate system, including land and ocean processes. They can not replicate the physics &lt;em&gt;exactly&lt;/em&gt;, because:&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;they operate on scales of a few hundred meters at minimum, and so physical processes (which usually operate on &lt;em&gt;much&lt;/em&gt; smaller scales) are scaled up and parameterised to work on the larger scale; and &lt;/li&gt;&#xA;&lt;li&gt;because for some of the physical processes (especially those that have to be parametrised to larger scales), there is not enough data to adequately fit them. When this happens, those model parameters are usually &lt;em&gt;calibrated&lt;/em&gt; - a large number of runs are made, with different values for those parameters, and then the best parameter values are chosen.&lt;/li&gt;&#xA;&lt;/ol&gt;&lt;/li&gt;&#xA;&lt;li&gt;Usually, you run the model for some period prior to the projection period, so that you can compare that to observations (spin-up period).&lt;/li&gt;&#xA;&lt;li&gt;You need to provide input data to the model. Mostly, this just consists of solar forcing (changes in the sun's output), as well as expected greenhouse gas (GHG) emissions, and aerosol emissions (both human and volcanic).&lt;/li&gt;&#xA;&lt;li&gt;Simulation output is in the same format as your observational data, and generally includes all of the important variables - temperature, precipitation, etc.&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;Put all of those simulations in an ensemble.&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Often, simulations are &quot;bias corrected&quot;, which usually means they are changed so that the model average matches the observation average over some period prior to the projection period - this might be the last 30-40 years. This is to allow for model drift (which is mostly chaotic, and can happen in any direction).&lt;/li&gt;&#xA;&lt;li&gt;The distribution of the simulations in the ensemble is used to create probabilistic projections. For example, each simulation has a mean global annual temperature. You could make the assumption that the errors in the simulations are normally distributed (over the ensemble), and so make an estimate of that distribution, and use that to make probabilistic estimates. This is basically saying that if ~50% of the models are over a certain temperature, you expect that (assuming the models, the input data, and assumptions they are based on are reliable*) there's a 50% chance that the global annual temperature of the earth would be over that temperature. A similar process can be used for the maximum temperature, or any other variable, and any statistics, including extremes indices. &lt;strong&gt;None of these predictions is a single value - they are always probabilistic, although it's probably quite common for only the mean of that distribution to be reported&lt;/strong&gt;.&lt;/li&gt;&#xA;&lt;li&gt;How you combine the information from the simulations in the ensemble is somewhat up to you. The basic method is as described above, and uses minimal assumptions about the data. It's also common for researchers to use a weighting methodology to estimate the ensemble mean, for example performance-based weighting, where models that perform better over the period before the projection are weighted more highly, with the assumption that they will perform better over the projection period too. Or you could weight based on model independence (if you're using multiple models), by weighting models that are less like other models more highly, in order to minimise bias from particular types of models (e.g. Bishop and Abramowitz 2013). &lt;em&gt;[I have a paper in review at the moment that investigates the efficacy of some of these methods, I'll link to it when it comes out]&lt;/em&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Can this process predict changes in 1000-year events&lt;/strong&gt;? Yes, potentially, even when the projection period is usually more like 100 years. This is because 1 in 1000-year events are actually defined inversely - that is, they are thought to have a 0.1% chance of occurring &lt;em&gt;in any given year&lt;/em&gt;. If your ensemble projects over 100 years, but has 100 simulations, then there are 10,000 years in which that a 1 in 1000 might occur. If you see it occurring 20 times, or 4 times, then you might get suspicious that things are changing. You probably need more than that to get a statistically significant result, but there are ensembles out there that are &lt;em&gt;really&lt;/em&gt; big (e.g. Stainforth et al, 2005, which had 2,578 simulations totalling over 100,000 simulated&#xA;years, and  I think some of the &lt;a href=&quot;http://www.climateprediction.net&quot; rel=&quot;nofollow&quot;&gt;ClimatePrediction.net&lt;/a&gt; have tens of thousands of simulations). Even without those large ensembles, if you assume particular distributions of extreme events where probability is a simple function of extremeness (e.g. Log-normal distribution or similar), then you can probably say something about large extremes based on the change in behaviour of less extreme events. Unfortunately, I am not aware of any experiments that look at the likely changes to very extreme events.&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;* Model reliability is obviously a fairly active field of debate and research. Suckling and Smith (2012) indicates that GCM-based ensembles are better than basic statistical models, but probably not currently much better than some more advanced statistical models. However, that still means that they're at least on-par with the best options we have for forecasting, unless you're in to reading chicken entrails.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;References&lt;/h2&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Bishop, C.H. &amp;amp; Abramowitz, G., 2013. Climate model dependence and the replicate Earth paradigm. Climate Dynamics, 41(3-4), pp.885–900. Available at: &lt;a href=&quot;http://link.springer.com/article/10.1007/s00382-012-1610-y&quot; rel=&quot;nofollow&quot;&gt;http://link.springer.com/article/10.1007/s00382-012-1610-y&lt;/a&gt; [Accessed September 17, 2013].&lt;/li&gt;&#xA;&lt;li&gt;Stainforth, D.A. et al., 2005. Uncertainty in predictions of the climate response to rising levels of greenhouse gases. Nature, 433(7024), pp.403–406. Available at: &lt;a href=&quot;http://www.nature.com/nature/journal/v433/n7024/abs/nature03301.html&quot; rel=&quot;nofollow&quot;&gt;http://www.nature.com/nature/journal/v433/n7024/abs/nature03301.html&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Suckling, E.B. &amp;amp; Smith, L.A., 2013. An Evaluation of Decadal Probability Forecasts from State-of-the-Art Climate Models*. Journal of Climate, 26(23), pp.9334–9347. Available at: &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-12-00485.1&quot; rel=&quot;nofollow&quot;&gt;http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-12-00485.1&lt;/a&gt; [Accessed January 8, 2015].&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="56" LastEditorUserId="56" LastEditDate="2016-05-01T02:09:46.330" LastActivityDate="2016-05-01T02:09:46.330" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="4216" PostTypeId="1" AcceptedAnswerId="4223" CreationDate="2015-01-08T06:37:14.403" Score="8" ViewCount="944" Body="&lt;p&gt;Are there any recognized studies on the effectiveness of sand-bags in protecting property in some disaster or flood? Many times on the major news they talk about how sand-bags are used in a flood , how many people 'pull' together and make a great effort to save various properties. The thing is in many such instances the News people do not follow up on whether the sand-bags held. There has been a few mentions of it being successful but they do not mention much if or when the sand bags actually fail. So have there been any official studies in the effectiveness of sand bags?&lt;/p&gt;&#xA;" OwnerUserId="1371" LastActivityDate="2015-01-09T06:41:11.717" Title="About the effectiveness of sand-bags" Tags="|human-influence|severe-weather|environmental-protection|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="4217" PostTypeId="2" ParentId="3196" CreationDate="2015-01-08T06:58:12.737" Score="7" Body="&lt;p&gt;Great question, with some interesting answers. It's obviously struck a chord around here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd just like to add the abstract from one of my favourite papers, by Oreskes, Shrader-Frechette, &amp;amp; Beiitz (1994):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Verification and validation of numerical models of natural systems is impossible. This is because natural systems are never closed and because model results are always non-unique. Models can be confirmed by the demonstration of agreement between observation and prediction, but confirmation is inherently partial. Complete confirmation is logically precluded by the fallacy of affirming the consequent and by incomplete access to natural phenomena. Models can only be evaluated in relative terms, and their predictive value is always open to question. The primary value of models is heuristic.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Basically, in a complex system, you'd never expect a model's results to match observed data - there is noise everywhere, but also these systems contain deterministic chaos. You can simulate the behaviour of such a system, but you can't simulate the &lt;em&gt;results&lt;/em&gt;. Even if your model is exactly correct, with the correct inputs, you won't get the same behaviour, because even the slightest value truncation will lead to a significant divergence, eventually.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, even if you do get the &lt;em&gt;exact result&lt;/em&gt; you can't know that you got the right result for the right reasons - equifinality is a real problem. &lt;em&gt;Especially&lt;/em&gt; in a model with more than two interacting calibrated parameters. There is no guarantee that the calibration process will give you better parameters, you can only be sure that it will give you better results &lt;em&gt;for the calibration data&lt;/em&gt;. Even calibration using a cross-validation methodology (train-and-test) with actually independent data (rare) might fail, because the validation part can fail for the above reasons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyway, everyone interested in that this topic should read that paper, I'm sure I've missed points here. It is a bit heavy-going, but that's because of the concepts - the paper is actually pretty enjoyable to read.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;References&lt;/h3&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Oreskes, N., Shrader-Frechette, K. &amp;amp; Beiitz, K., 1994. Verification, validation, and confirmation of numerical models in the Earth sciences. Science, 263(5147), pp.641–646. Available at: &lt;a href=&quot;http://search.proquest.com/docview/733194143/14125288294380DFD60/1?accountid=12763&quot; rel=&quot;nofollow&quot;&gt;ProQuest&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="56" LastEditorUserId="6093" LastEditDate="2016-10-14T03:08:34.700" LastActivityDate="2016-10-14T03:08:34.700" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4218" PostTypeId="2" ParentId="4211" CreationDate="2015-01-08T13:29:27.843" Score="4" Body="&lt;p&gt;It depends what your practical purposes are. Maybe you can treat it as 0. But in general, no, because it is not closed, due to geothermal heat flux, and anthropogenic imbalances. Also, even if assuming 0, that would be over long time scales and integrated over the earth surface. There are spatial heterogeneities. &lt;/p&gt;&#xA;" OwnerUserId="1354" LastEditorUserId="1354" LastEditDate="2015-01-08T17:35:56.603" LastActivityDate="2015-01-08T17:35:56.603" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4219" PostTypeId="2" ParentId="2917" CreationDate="2015-01-09T00:06:07.770" Score="7" Body="&lt;p&gt;In some capacity, differential heating is responsible for convective motion of the ocean due to buoyant forces. However, it is possible to show that the net (vertically integrated) horizontal transport in most of the ocean is solely due to the action of the wind stress on the water surface (Sverdrup, 1947). In other words, the pattern of major ocean currents is a direct mirror of the pattern of the wind stress.&lt;/p&gt;&#xA;&lt;p&gt;The main reason the current is intensified in the western boundary is because of the &lt;span class=&quot;math-container&quot;&gt;$\beta$&lt;/span&gt;-effect, or the strengthening of Coriolis with latitude. This effect causes the slope of the ocean surface to be steeper on the western side because the equator easterlies are stronger than the mid-latitude westerlies and therefore surface water piles up in the western boundary. Due to conservation of potential vorticity the steeper slope results in faster geostrophic flow on that side of the gyre (i.e. western intensification).&lt;/p&gt;&#xA;&lt;p&gt;Another cause for the westward intensification are the density gradients, namely the sign of the gradient of zonal density. For example, if the density in the polar regions suddenly became less than the density in the equator regions, the Western boundary current would be considerably weaker. Another argument explains the phenomenon of western intensification via the accumulation of energy due to westward propagating planetary Rossby waves.&lt;/p&gt;&#xA;&lt;p&gt;If we assume that the current velocity in the Gulf stream is &lt;span class=&quot;math-container&quot;&gt;$U \sim 1$&lt;/span&gt; m/s on average (its maximum may be twice that) then the momentum per unit volume of a fluid parcel will be &lt;span class=&quot;math-container&quot;&gt;$\rho U \sim 1000$&lt;/span&gt; kg m&lt;span class=&quot;math-container&quot;&gt;$^{-2}$&lt;/span&gt; s&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt;. Typical estimates suggest the total mass transport across a cross section of the Gulf stream is on the order of &lt;span class=&quot;math-container&quot;&gt;$90 \cdot 10^6$&lt;/span&gt; m&lt;span class=&quot;math-container&quot;&gt;$^{3}$&lt;/span&gt; s&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt; of water. By comparison, the momentum of a fluid element in the jet stream in the atmosphere is one order of magnitude smaller than that in the Gulf stream, despite the fact that the wind speed is one hundred times larger than the water current speed.&lt;/p&gt;&#xA;&lt;p&gt;Assume the gulf stream has a total volume &lt;span class=&quot;math-container&quot;&gt;$V = L \cdot W \cdot D$&lt;/span&gt;, where the length &lt;span class=&quot;math-container&quot;&gt;$L = 2500$&lt;/span&gt; km, the width &lt;span class=&quot;math-container&quot;&gt;$W = 75$&lt;/span&gt; km and the depth &lt;span class=&quot;math-container&quot;&gt;$D = 800$&lt;/span&gt; m then, as a crude approximation, we can estimate the total force &lt;span class=&quot;math-container&quot;&gt;$F$&lt;/span&gt; that must act on the fluid over (lets say) &lt;span class=&quot;math-container&quot;&gt;$2$&lt;/span&gt; years to cause a sufficient change in the bulk fluid momentum &lt;span class=&quot;math-container&quot;&gt;$m \Delta v = \rho V \Delta v$&lt;/span&gt; so that the Gulf Stream comes to a stop. From Newton's Second Law and plugging in some typical values:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$F = m \frac{\Delta v}{\Delta t} = 2.5 \cdot 10^9$&lt;/span&gt;N&lt;/p&gt;&#xA;&lt;p&gt;Suppose the force is applied through a surface wind and suppose its action extends all the way to the bottom of the current. Then one would require a wind stress &lt;span class=&quot;math-container&quot;&gt;$\tau = 0.01$&lt;/span&gt; Pa acting for at least two years, of course that number would need to be higher since in reality the wind stress accelerates the top layer of the water column, and its effect weakens with depth. Note that typical oceanic values of wind stresses are about &lt;span class=&quot;math-container&quot;&gt;$0.1$&lt;/span&gt; Pa. This indicates that, purely from physical principles, stopping the Gulf stream within two years is realistic.&lt;/p&gt;&#xA;&lt;p&gt;However, it is not possible without a complete reversal of well established wind patterns combined with a drastic reduction in the density near the poles compared to near the equator. The latter is why some models predict future slowdown of the Gulf Stream, as the anthropogenic heating of the earth causes the melting of polar ice, the ocean water becomes fresher and less dense. Fortunately, as @naught101 pointed out, changes of that magnitude are unlikely to take place in the near future.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1079064/pdf/pnas01704-0018.pdf&quot; rel=&quot;noreferrer&quot;&gt;Sverdrup, Harald Ulrich. &amp;quot;Wind-driven currents in a baroclinic ocean; with application to the equatorial currents of the eastern Pacific.&amp;quot; Proceedings of the National Academy of Sciences of the United States of America 33.11 (1947): 318.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Pedlosky, Joseph. &amp;quot;Geophysical fluid dynamics.&amp;quot; New York and Berlin, Springer-Verlag, 1982. 636 p. 1 (1982).&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-01-09T01:33:38.693" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4220" PostTypeId="1" AcceptedAnswerId="4221" CreationDate="2015-01-09T01:13:47.087" Score="30" ViewCount="9755" Body="&lt;p&gt;The other day a friend of my dad's showed him a picture of an icicle that appeared to be &quot;growing&quot; upwards out of a crack in a sidewalk. There were no roofs, overhangs or vehicles parked near by... It looked like a stalagmite you would see in a cave. It looked something like this&lt;sup&gt;*&lt;/sup&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/870wo.jpg&quot; alt=&quot;ice stalagmite&quot;&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How could this happen? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;* Note that this is not the actual icicle, I used this picture for an example.&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="342" LastEditorUserId="595" LastEditDate="2016-01-19T22:25:30.220" LastActivityDate="2017-01-04T09:50:20.727" Title="How would an icicle &quot;grow&quot; upwards?" Tags="|meteorology|glaciology|ice|" AnswerCount="3" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="4221" PostTypeId="2" ParentId="4220" CreationDate="2015-01-09T03:06:43.490" Score="27" Body="&lt;p&gt;If there is enough water underground, in a sealed reservoir (like under the concrete in the picture), as that water freezes, it will expand, putting pressure on what ever water is left unfrozen. That water will be squeezed out through what ever cracks it can find - in this case, upwards. Because the water is already near-freezing (perhaps even slightly below, if it's super cooled), it will freeze &lt;em&gt;very&lt;/em&gt; quickly when it hits the air (which will be much colder than the ground, late at night). But if there is still water being pushed up from below, that ice will have to move out of the way (it's weaker than concrete). The friction of the flow of cool upwards might warm it just enough to keep it liquid, and the &quot;stalagmite&quot; will end up with a hollow core that the water is being pumped through, and that structure can just keep building on itself, until it is toppled by wind or gravity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The picture is a bit grainy, but it looks like that's what's happened there. It also looks like the side of the hollow &quot;stalagmite&quot; has fallen off up the top, and released a bit of the remaining water (or maybe it just melted in the sun).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt; Hah, I knew I'd seen this somewhere before - in my freezer! &lt;a href=&quot;http://www.its.caltech.edu/~atomic/snowcrystals/icespikes/icespikes.htm&quot;&gt;This page&lt;/a&gt; describes how &lt;strong&gt;Ice spikes&lt;/strong&gt; form - I basically got it right. It seems that they're more likely to form with de-mineralised water, and the temperature has to be within certain narrow limits.&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="56" LastEditDate="2015-01-09T03:40:08.993" LastActivityDate="2015-01-09T03:40:08.993" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4223" PostTypeId="2" ParentId="4216" CreationDate="2015-01-09T06:41:11.717" Score="6" Body="&lt;p&gt;There have been a few studies related to the effectiveness of sandbags in flood events, these are usually based on observations performed after flood events.  Overall, studies have shown that sandbags only have modest protection in its use as a domestic (&lt;a href=&quot;http://www.uibk.ac.at/fakultaeten/volkswirtschaft_und_statistik/forschung/alpinerraum/seminar09/botzen_aerts_vandenbergh_mitigating_flood_risks_through_insurance-09-08.pdf&quot;&gt;1&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A major factor the research shows is that the maximum effectiveness occurs to about 1 metre depth (&lt;a href=&quot;http://www.uibk.ac.at/fakultaeten/volkswirtschaft_und_statistik/forschung/alpinerraum/seminar09/botzen_aerts_vandenbergh_mitigating_flood_risks_through_insurance-09-08.pdf&quot;&gt;1&lt;/a&gt;), they can, on occasion, hold out in higher flood levels, but as Reeve and Badr (&lt;a href=&quot;http://www.icevirtuallibrary.com/content/article/10.1680/wame.2003.156.4.341&quot;&gt;2&lt;/a&gt;) determined, leakage between the bags increases rapidly with increasing flood water levels.  However, due to the unique nature of each flood conditions, there is still a large degree of uncertainty as to what effectiveness actually means in terms of sandbags (&lt;a href=&quot;http://www.uibk.ac.at/fakultaeten/volkswirtschaft_und_statistik/forschung/alpinerraum/seminar09/botzen_aerts_vandenbergh_mitigating_flood_risks_through_insurance-09-08.pdf&quot;&gt;1&lt;/a&gt;).  However, the major degree of effectiveness is highly dependent on the number of rows of sandbags and the duration of the flood (&lt;a href=&quot;http://www.icevirtuallibrary.com/content/article/10.1680/wame.2003.156.4.341&quot;&gt;2&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Asides from floodwater height and duration, and height of sandbags, other factors that affect their effectiveness include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Waves on the flood waters increase instability of sandbag walls/dikes, especially as floodwater depth increases (&lt;a href=&quot;http://ullr.lib.umanitoba.ca/handle/1993/3151&quot;&gt;5&lt;/a&gt;).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Ambient conditions - temperature mainly, if low enough - ice could form between the bags decreasing their effectiveness (&lt;a href=&quot;http://ullr.lib.umanitoba.ca/handle/1993/3151&quot;&gt;5&lt;/a&gt;).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Speed of flood waters - having eyewitnessing (and being caught in) a flash flood (&lt;a href=&quot;https://www.youtube.com/watch?v=-Bn1juJs1oI&quot;&gt;3&lt;/a&gt;), fast moving water itself (and the debris it invariably contains) can severely degrade the effectiveness of sandbags.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The time taken to build the sandbag wall, as well as build up the height of the wall should the flood levels rise.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In reference to the comment about alternatives, one major alternative is preventative action, even though it is impossible to fully protect against floods, particularly large-scale and flash-flooding. After the 2002 floods of the Elbe River in Germany, it was found that household preventative measures &lt;em&gt;lessen&lt;/em&gt; the damage from a large scale flood (&lt;a href=&quot;https://hal.archives-ouvertes.fr/hal-00299130/&quot;&gt;4&lt;/a&gt;).  Related, flood minimalisation techniques are explored including soil bioengineering (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0925857414005916&quot;&gt;6&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.uibk.ac.at/fakultaeten/volkswirtschaft_und_statistik/forschung/alpinerraum/seminar09/botzen_aerts_vandenbergh_mitigating_flood_risks_through_insurance-09-08.pdf&quot;&gt;1&lt;/a&gt;) Botzen et al. 2008 &lt;a href=&quot;http://www.uibk.ac.at/fakultaeten/volkswirtschaft_und_statistik/forschung/alpinerraum/seminar09/botzen_aerts_vandenbergh_mitigating_flood_risks_through_insurance-09-08.pdf&quot;&gt;Willingness of Homeowners to Mitigate Climate Risk through&#xA;Insurance&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.icevirtuallibrary.com/content/article/10.1680/wame.2003.156.4.341&quot;&gt;2&lt;/a&gt;) Reeve and Badr, 2003 &lt;a href=&quot;http://www.icevirtuallibrary.com/content/article/10.1680/wame.2003.156.4.341&quot;&gt;Performance of sandbags for domestic flood defence&lt;/a&gt;, &lt;em&gt;Proceedings of the ICE - Water and Maritime Engineering, Volume 156, Issue 4, 01&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;https://www.youtube.com/watch?v=-Bn1juJs1oI&quot;&gt;3&lt;/a&gt;) &lt;a href=&quot;https://www.youtube.com/watch?v=-Bn1juJs1oI&quot;&gt;Worst Queensland Floods In 35 Years 11/01/11&lt;/a&gt; &lt;em&gt;YouTube news clip&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;https://hal.archives-ouvertes.fr/hal-00299130/&quot;&gt;4&lt;/a&gt;) Kreibich et al. 2005 &lt;a href=&quot;https://hal.archives-ouvertes.fr/hal-00299130/&quot;&gt;Flood loss reduction of private households due to building precautionary measures -- lessons learned from the Elbe flood in August 2002&lt;/a&gt; &lt;em&gt;Natural Hazards and Earth System Science&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://ullr.lib.umanitoba.ca/handle/1993/3151&quot;&gt;5&lt;/a&gt;) Raymond, 2009, &lt;a href=&quot;http://ullr.lib.umanitoba.ca/handle/1993/3151&quot;&gt;Wave action and the effects of the environment on sandbag dike performance&lt;/a&gt; &lt;em&gt;Thesis - University of Manitoba&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0925857414005916&quot;&gt;6&lt;/a&gt;) Dhital and Tang, 2015 &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0925857414005916&quot;&gt;Soil bioengineering application for flood hazard minimization in the foothills of Siwaliks, Nepal&lt;/a&gt; &lt;em&gt;Ecological Engineering&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2015-01-09T06:41:11.717" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="4225" PostTypeId="2" ParentId="4220" CreationDate="2015-01-09T10:47:35.000" Score="11" Body="&lt;p&gt;Ice can grow up from the ground in the form of needle ice. The formation requires  sufficient moisture in the ground. According to the &lt;a href=&quot;https://nsidc.org/cryosphere/frozenground/how_fg_affects_land.html&quot;&gt;National Snow and Ice Data Center (NSIDC)&lt;/a&gt; site needle ice can grow up to 40 cm in length. Needle ice are thin crystals of ice and has a very distinct look. A search on &lt;em&gt;Needle Ice&lt;/em&gt; provides a wealth of examples of needle ice, note that all pictures are not relevant! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Needle ice can also form from plants if suddenly subjected to very low temperatures and where moisture in the plant has limited escape possibilities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The picture in the post is, however, not needle ice, it is clearly a form of icicle. In fact the common icicle is reminiscent to a stalactite forming from a cave ceiling. Corresponding to the stalactite, a stalagmite forms on the floor. The ice form on the picture is a &lt;em&gt;stalagmite&lt;/em&gt; form, created by water dripping from a structure down onto the ground in sub-freezing temperatures (credit to geotheory).&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2015-01-09T10:47:35.000" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4226" PostTypeId="1" AcceptedAnswerId="4228" CreationDate="2015-01-09T11:48:33.593" Score="15" ViewCount="4005" Body="&lt;p&gt;I have noticed this winter that nights without clouds (especially when the 12h before the night where not cloudy) were way colder than the cloudy ones. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It makes sense to me because the clouds can reflect the heat (infrared?) earth have accumulated during the day rather than loosing it into the atmosphere (like a kind of blanket). But I could be &quot;swayed&quot; by a confirmation bias here, so here is my question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a correlation between temperature and cloud, &lt;strong&gt;during the night&lt;/strong&gt;?&lt;/p&gt;&#xA;" OwnerUserId="1315" LastEditorUserId="543" LastEditDate="2016-01-18T22:46:49.617" LastActivityDate="2016-01-18T22:46:49.617" Title="Are cloudy nights warmer than nights without clouds?" Tags="|meteorology|temperature|clouds|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4227" PostTypeId="1" AcceptedAnswerId="4229" CreationDate="2015-01-09T16:20:20.413" Score="13" ViewCount="1063" Body="&lt;p&gt;I'm trying to understand why there are differing predictions of the atmospheric temperature profile. It is well established that the dry adiabatic lapse rate (DALR) is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\frac{\mathrm{d}T}{\mathrm{d}z} = -\frac{g}{c_p} \approx -9.8\ \mathrm{K/km}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is derived by assuming adiabatic process and hydrostatic pressure gradient:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\mathrm{d}s = c_p\mathrm{d}\ln{T} - R\mathrm{d}\ln{p}\quad(= \frac{\delta q}{T} = 0)\\&#xA;\quad \frac{\mathrm{d}p}{\mathrm{d}z} = -\rho' g&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\rho'$ is density of ambient air, and pressure of an air parcel is the same as ambient pressure ($p = p'$). It is essenitally the cooling an air parcel will experience due to change in ambient pressure when risen adiabatically in the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, when using the principle of maximum entropy (i.e. looking for the equilibrium profile) we get &lt;em&gt;isothermal profile&lt;/em&gt;, as predicted classically by Gibbs and Boltzmann.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apparently, the actual atmospheric profile (where there is no moisture condensing) is consistent with the dry adiabatic lapse rate much more than with the isothermal profile. The actual profile is of course subject to continuous thermal cooling of the atmospheric layers, thermal warming by radiation from the Earth's surface, heating from the surface by conduction (by turbulence and molecular diffusion), and during the day to solar heating. These factors can obviously affect any equilibrium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;What causes the discrepancy? Is there a consensus?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;If there was initially a DALR profile, would it eventually turn into an isothermal profile if there was no influence (no radiation, no surface, no dynamic phenomena).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;My impression is that when radiative processes (thermal cooling and thermal heating from surface) are included in the maximum entropy calculation, one might get some sort of lapse rate, i.e. something between a pure thermal radiative profile and the isothermal profile.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found some papers discussing the issue, esp.:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Verkley WTM., Gerkema T, 2003. &lt;a href=&quot;http://www.nioz.nl/files/upload/users/258010/2004-JAS.pdf&quot;&gt;On Maximum Entropy Profiles&lt;/a&gt;. &lt;em&gt;Journal of atmospheric sciences&lt;/em&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Akmaev RA., 2008. &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/qj.209/pdf&quot;&gt;On the energetics of maximum‐entropy temperature profiles&lt;/a&gt;. &lt;em&gt;Quarterly Journal of the Royal Meteorological Society&lt;/em&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;where they treat potential temperature as something which is conserved when applying the maximum entropy principle in order to reach a profile with a lapse rate. But it is not clear to me why such an assumption should be made, or if there is any general consensus that this is the right approach.&lt;/p&gt;&#xA;" OwnerUserId="1265" LastEditorUserId="1265" LastEditDate="2015-01-09T19:02:42.477" LastActivityDate="2015-01-09T19:02:42.477" Title="Dry atmospheric temperature profile (dry adiabatic vs. isothermal)" Tags="|meteorology|atmosphere|temperature|radiative-transfer|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4228" PostTypeId="2" ParentId="4226" CreationDate="2015-01-09T17:03:11.120" Score="16" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is there a correlation between temperature and cloud, during the night?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Very much so. It's called radiative cooling. Three factors come into play: cloudiness, relative humidity, and windiness. Nighttime radiative cooling is greatest under clear skies, low relative humidity, and light or no winds. The temperature drop (in degrees per hour) can be a factor of more than four greater under conditions of clear skies, low humidity, and light winds compared to that under conditions of thick low clouds and high relative humidity. That increased cooling can make for a significant temperature drop on a long winter night.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-01-09T17:03:11.120" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="4229" PostTypeId="2" ParentId="4227" CreationDate="2015-01-09T18:15:55.257" Score="11" Body="&lt;p&gt;The two articles you found are spot-on. An isothermal atmosphere is indeed the condition that maximizes entropy for a given amount of energy. Yet a positive lapse rate is almost always observed. Temperature typically decreases with increasing altitude. The key to resolving this apparent paradox is how heat flows into and through the Earth's atmosphere. The Earth's atmosphere is a system that is very far from equilibrium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the atmosphere isn't in that maximum entropy state (and it never is, at least not from very bottom to very top), heat transfer will set up to put move it toward that state. Very key: That entropy-driven heat transfer rate is rather low. If other heat transfer processes are in play (and they always are), it is very easy to overwhelm that low entropy-driven heat transfer that would nominally equalize the temperature. The Earth's troposphere is heated from below and cooled from above. This alone overwhelms the entropy-driven heat transfer, and by multiple orders of magnitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other factor is how heat flows through the atmosphere. The presence of greenhouse gases in the atmosphere set up the conditions that make a positive lapse rate possible. By way of analogy, imagine a perfect blackbody heat source that generates heat at a rate $Q$ and has a surface area A. If that heat source radiates to the dark sky, the equilibrium temperature will be given by the Stefan-Boltzmann law, $T_\text{top} = (Q/(\sigma A))^{1/4}$. (Note: I'm assuming that $Q$ is much, much greater than the tiny amount of heat coming in from the cosmic microwave background.) If you put a perfect blackbody blanket atop that heat source, the blanket will radiate at a rate $Q$ outward and inward. The heat source will receive heat from above and below, making the equilibrium temperature of the heat source with one blanket equal to $(2Q/(\sigma A))^{1/4}$, or $2^{1/4} T_\text{top}$. Yet another blanket makes the thermal equilibrium equal to $3^{1/4} T_\text{top}$, and so on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The atmosphere with its greenhouse gases that are optically thick in the thermal infrared acts as a bunch of blankets. Obviously not perfect blackbody blankets, but blankets nonetheless. This is what favors the development of a positive lapse rate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This favoring isn't universal. There are times when weather creates conditions where the lapse rate is negative, that is, temperature increases with altitude. This turns out to be a very stable condition (the name for this is a &quot;very stable atmosphere&quot;). This negative lapse rate precludes rising and falling parcels of air. With calm air as well, the only thing that can transfer heat is diffusion, which is a very slow process in the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-01-09T18:15:55.257" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4230" PostTypeId="1" AcceptedAnswerId="4236" CreationDate="2015-01-09T21:13:20.733" Score="12" ViewCount="123" Body="&lt;p&gt;The &lt;a href=&quot;http://icecube.wisc.edu/&quot;&gt;IceCube&lt;/a&gt; is a particle detector at the South Pole that records neutrino interactions. It has lead to many fascinating new discoveries in the field of astrophysics (e.g., &lt;a href=&quot;http://www.livescience.com/6801-antarctica-experiment-discovers-puzzling-space-ray-pattern.html&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;http://arxiv.org/abs/1305.6811&quot;&gt;2&lt;/a&gt;) and it was awarded &lt;a href=&quot;http://icecube.wisc.edu/gallery/press/view/1618&quot;&gt;&quot;Breakthrough of the Year 2013&quot;&lt;/a&gt; by Physics World. My question is whether the process of installation and operation of such an extensive array has provided any new knowledge of the geophysical characteristics of the Antarctic.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="81" LastEditDate="2015-01-10T17:22:24.470" LastActivityDate="2018-01-28T11:22:50.383" Title="What geophysical knowledge have we learned by the construction of IceCube?" Tags="|geophysics|glaciology|antarctic|ice-sheets|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4231" PostTypeId="1" AcceptedAnswerId="4243" CreationDate="2015-01-09T21:59:36.590" Score="7" ViewCount="307" Body="&lt;p&gt;I often find the term &lt;em&gt;Alpine schistosity&lt;/em&gt; (&lt;em&gt;schistosité alpine&lt;/em&gt; in French, &lt;em&gt;scistosità alpina&lt;/em&gt; in Italian) in texts about Alpine geology. Chronologically ordered phases of &lt;em&gt;Alpine schistosity&lt;/em&gt; producing different schistous foliations are named, in everything I have read, S$_1$, S$_2$ (and S$_3$).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think that notations S$_1$, S$_2$, ..., S$_n$ may well refer to any ordered orogenetic phases producing schistosity in any rock, anywhere, at any time. Please correct me if I am wrong.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nevertheless, I wonder whether, when talking about S$_1$ &lt;em&gt;Alpine schistosity&lt;/em&gt;, or S$_2$ &lt;em&gt;Alpine schistosity&lt;/em&gt;, one usually refers to a well defined temporal phase of Alpine orogeny producing a particular schistous foliation. Is that so?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyhow, I must remark that all schistosities that S$_1$ and S$_2$ in the geology of the Alps not necessarily refer to foliations generated during the Alpine orogeny, since for example in Briançonnais orthogneiss it is usual to distinguish a Silurian-Ordovician S$_1$ schistosity and a late Carboniferous S$_2$ schistosity, both generated before the Alpine orogeny.&#xA;I thank you very much for any answer!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*Vv.Aa., &lt;a href=&quot;http://www.socgeol.it/551/2_-._Alpi_Liguri.html&quot; rel=&quot;nofollow&quot;&gt;&lt;em&gt;Alpi liguri&lt;/em&gt;&lt;/a&gt;, edited by the Italian Geological Society.&lt;/p&gt;&#xA;" OwnerUserId="620" LastEditorUserId="620" LastEditDate="2015-01-10T10:27:25.647" LastActivityDate="2015-01-11T07:03:55.480" Title="Alpine schistosity" Tags="|geology|orogeny|regional-geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4232" PostTypeId="1" AcceptedAnswerId="4233" CreationDate="2015-01-10T02:02:53.397" Score="19" ViewCount="380" Body="&lt;p&gt;In May, 2006, the Lusi Mud Volcano in eastern Java, Indonesia came to life, smothering much of the surrounding land in mud. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the article &lt;a href=&quot;http://news.sciencemag.org/asia/2011/02/indonesias-infamous-mud-volcano-could-outlive-all-us&quot;&gt;Indonesia's Infamous Mud Volcano Could Outlive All of Us&lt;/a&gt; (Normile, 2011), there is considerable uncertainty about what actually triggered the eruption in the first place.  The main ideas of what possibly caused the eruption, as reported in the article are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Nearby drilling&lt;/li&gt;&#xA;&lt;li&gt;A relatively nearby 6.3 magnitude earthquake 2 days earlier.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is there any consensus of what caused the Lusi Mud Volcano eruptions in Indonesia?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2015-09-11T01:28:40.997" Title="Is there any consensus of what caused the Lusi Mud Volcano eruptions in Indonesia?" Tags="|volcanology|volcanic-hazard|mud-volcano|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4233" PostTypeId="2" ParentId="4232" CreationDate="2015-01-10T12:27:59.657" Score="11" Body="&lt;p&gt;&lt;strong&gt;No, there is no consensus.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact, there's quite a bit of debate about it — around the 2 causes you mentioned. To sum up the proposed triggers:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The eruption happened about 2 days after &lt;a href=&quot;http://en.wikipedia.org/wiki/May_2006_Java_earthquake&quot;&gt;the 2006 Yogyakarta earthquake&lt;/a&gt;, which killed over 5000 people. Lupi et al (2013), Sawolo et al. (2011), and others including the Indonesian government, favour this as the trigger. &lt;/li&gt;&#xA;&lt;li&gt;The eruption happened about 200 m away from Lapindo Brantas's Banjar Panji 1 exploration well. There were early signs of trouble in the well, which started when the earthquake happened. At the time, the incident was treated as a blow-out, relief wells were drilled, etc. Davies et al. (2011), and others, blame this. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Last year &lt;a href=&quot;http://www.agilegeoscience.com/blog/2014/5/28/lusis-8th-birthday.html&quot;&gt;I blogged about Lusi&lt;/a&gt;. The first-order cause was not my focus (though I insinuated that I thought the well exploited a predisposition set up by the earthquake); I focused instead on the history of the event. But much of the controversy emerged &lt;a href=&quot;http://www.agilegeoscience.com/blog/2014/5/28/lusis-8th-birthday.html#comments&quot;&gt;in the comments&lt;/a&gt;, which are worth reading. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rather than trying to synthesize everything into an elegant summary, I'll just point out two of the complications in all this:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The Lupi et al (2013) argument has serious flaws, because the authors misinterpreted the sonic (DT) log from the well. This was partly, but not completely, resolved by &lt;a href=&quot;http://www.nature.com/ngeo/journal/v7/n9/full/ngeo2239.html&quot;&gt;the corrigendum&lt;/a&gt; published in 2014. In a nutshell, the fast layer they argued for was a logging artifact.&lt;/li&gt;&#xA;&lt;li&gt;There is a legal backdrop to the argument, which may not be compatible with an objective scientific debate. For the company, there is the question of liability and thus reparations, which could be expensive. For the government, there is the question of international financial relief, some of which is contingent on Lusi being a natural disaster. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The debate may not be satisfactorily resolved for some time. It seems to be one of those unhelpful debates where, to the participants at least, there is no uncertainty. My heuristic in such situations is to assume this means that &quot;it's complicated&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Davies, R, S Mathias, R Swarbrick and M Tingay (2011). Probabilistic longevity estimate for the LUSI mud volcano, East Java. Journal of the Geological Society 168, 517–523. &lt;a href=&quot;http://dx.doi.org/10.1144/0016-76492010-129&quot;&gt;DOI 10.1144/0016-76492010-129&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Lupi, M, EH Saenger, F Fuchs and SA Miller (2013). Lusi mud eruption triggered by geometric focusing of seismic waves. Nature Geoscience 6, 642–646 (2013) &lt;a href=&quot;http://dx.doi.org/10.1038/ngeo1884&quot;&gt;DOI 10.1038/ngeo1884&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Sawolo, N, E Sutriono, B Istadi, A Darmoyo (2009). The LUSI mud volcano triggering controversy: was it caused by drilling? Marine &amp;amp; Petroleum Geology 26 (9), 1766–1784. &lt;a href=&quot;http://dx.doi.org/10.1016/j.marpetgeo.2009.04.002&quot;&gt;DOI 10.1016/j.marpetgeo.2009.04.002&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-01-10T12:27:59.657" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4234" PostTypeId="1" AcceptedAnswerId="4235" CreationDate="2015-01-10T15:47:49.847" Score="15" ViewCount="8983" Body="&lt;p&gt;We have had some stations report snow that have not reported snow in the past 55 years at sea level. I have read that Tampico, Mexico at 22°N is one of the stations that has recorded snow in the tropics. What is the lowest latitude at which recent snowfall(as recorded by humans) has been recorded at sea level? Please note that the question is very specific to snowfall and not merely the lowest temperature recorded in the tropics (subzero)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question is hemisphere agnostic. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2016-10-03T04:34:17.253" LastActivityDate="2016-10-03T04:34:17.253" Title="What is the lowest latitude at which snow has been recorded at sea level?" Tags="|meteorology|snow|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4235" PostTypeId="2" ParentId="4234" CreationDate="2015-01-10T16:43:18.963" Score="12" Body="&lt;p&gt;According to the USA Today article &lt;a href=&quot;http://usatoday30.usatoday.com/weather/resources/askjack/wasnow.htm&quot; rel=&quot;noreferrer&quot;&gt;Answers archive: Winter, snow, ice&lt;/a&gt;, the sea level snow closest to the equator in recorded history are as follows.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The record for either hemisphere was in 1654, in the Chinese city of Nanning (now near present day Beihai) recorded snow, it is situated at 21°29'N.  This cold period is included in the article &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/joc.1552/pdf&quot; rel=&quot;noreferrer&quot;&gt;Coherence of climatic reconstruction from historical&#xA;documents in China by different studies&lt;/a&gt; (Ge et al. 2008) as part of a historical document that stated:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;‘The winter in the 11th year of Shunzhi (1654 A.D.) was&#xA;  severely cold&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;For reference, the USA Today article states that the Southern Hemisphere record was considerably further from the equator, occurring in Valparaiso, Chile (33°02'S) in 1977. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One major caveat to this answer (asides from the USAToday source) is the length of time that records have been kept - for China, it has been thousands of years - there is virtually no equivalent record keeping in many areas (particularly in the Southern Hemisphere) for that length of time.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Having said that, according to the &lt;a href=&quot;http://www.qgso.qld.gov.au/products/reports/qld-past-present/qld-past-present-1896-1996-ch02-sec-02.pdf&quot; rel=&quot;noreferrer&quot;&gt;Australian Bureau of Meteorology&lt;/a&gt;, snow has been recorded in the 1950's and 1960's, several hundred kilometres north of Brisbane, the furthest north was in the Clark Ranges, west of Mackay at a latitude of about 21°S- but these locations were considerably higher than sea level, so do not qualify.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From personal experience, I recall when I lived in the southern suburbs (at sea level) of Melbourne as a child, one winter there was snow - melted as it hit the ground - but that is at a latitude of 38.2°S&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In geological history, it could be argued that snow may have preceded the glaciation at the equator during &lt;a href=&quot;http://www.snowballearth.org/&quot; rel=&quot;noreferrer&quot;&gt;Snowball Earth&lt;/a&gt; events, if proven to be true.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="200" LastEditDate="2015-01-11T06:34:09.407" LastActivityDate="2015-01-11T06:34:09.407" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4236" PostTypeId="2" ParentId="4230" CreationDate="2015-01-10T17:19:02.277" Score="11" Body="&lt;p&gt;IceCube was initiated as the Antarctic Muon And Neutrino Detector Array (AMANDA) project. Since the sensor array involved drilling deep holes vertically into the Antarctic ice sheet by melting ice, no ice cores were retrieved. The bore holes have, however, been used to construct temperature profiles through the Antarctic ice sheet published in a paper in &lt;a href=&quot;http://www.pnas.org/content/99/12/7844.full&quot; rel=&quot;nofollow noreferrer&quot;&gt;PNAS&lt;/a&gt;. Gathering information of internal temperature is important to understand, for example, basal geothermal heat fluxes and estimating whether or not the ice sheet base is at the melting point and can support liquid water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the glaciological literature, very little has been published but then the projects AMANDA and IceCube have never focussed on such questions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Price et al. (2002) &lt;em&gt;Temperature profile for glacial ice at the South Pole: Implications for life in a nearby subglacial lake&lt;/em&gt;. PNAS, 99, (12), 7844-7847. &lt;a href=&quot;https://doi.org/10.1073/pnas.082238999&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1073/pnas.082238999&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="725" LastEditDate="2018-01-28T11:22:50.383" LastActivityDate="2018-01-28T11:22:50.383" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4237" PostTypeId="5" CreationDate="2015-01-10T17:28:14.003" Score="0" Body="&lt;p&gt;The tag &lt;a href=&quot;/questions/tagged/ice-sheets&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged &amp;#39;ice-sheets&amp;#39;&quot; rel=&quot;tag&quot;&gt;ice-sheets&lt;/a&gt; concern questions on the great &lt;a href=&quot;https://en.wikipedia.org/wiki/Ice_sheet&quot; rel=&quot;nofollow noreferrer&quot;&gt;ice sheets&lt;/a&gt;, present and past. Ice sheets are defined as glaciers of such size that their flow is largely independent of underlying topography. Ice sheets are therefore of continental or sub-continental scale and not to be confused with ice fields (e.g. the Patagonian ice fields) and ice caps (e.g. Vatnajökull, Barnes Ice Cap).&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="11908" LastEditDate="2019-02-03T19:25:45.347" LastActivityDate="2019-02-03T19:25:45.347" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="4238" PostTypeId="4" CreationDate="2015-01-10T17:28:14.003" Score="0" Body="[ice-sheets] concerns questions on the large present and past continental scale ice sheets, such as Antarctica, Greenland, the Laurentide, Fennoscandian and Alpine ice sheets." OwnerUserId="81" LastEditorUserId="81" LastEditDate="2015-01-10T19:36:25.013" LastActivityDate="2015-01-10T19:36:25.013" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4239" PostTypeId="1" AcceptedAnswerId="4241" CreationDate="2015-01-10T17:39:43.473" Score="22" ViewCount="4394" Body="&lt;p&gt;Is there any institute out there collecting time series data of precipitation, and making them accessible online? I need data for a few different locations, but:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Low spatial resolution is fine. For example, if I need rainfall time series for France, a space-averaged value would be satisfactory.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Low accuracy is fine. For example, remote sensing rather than in situ, or rainfall measured in a few points and then interpolated, would be satisfactory as well.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="2423" LastEditorUserId="192" LastEditDate="2015-01-10T20:27:17.063" LastActivityDate="2017-03-29T13:18:17.033" Title="Is there a database of global rainfall time series?" Tags="|meteorology|measurements|hydrology|precipitation|" AnswerCount="5" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4240" PostTypeId="1" AcceptedAnswerId="4244" CreationDate="2015-01-10T19:29:10.220" Score="10" ViewCount="3668" Body="&lt;p&gt;I need to calculate the force that causes a weather balloon with a specific volume to rise. Having searched for quite a few hours, I found the needed formula that can be used to calculate the pressure at a certain altitude. (surprisingly, the formula given on the &lt;a href=&quot;http://de.wikipedia.org/wiki/Barometrische_H%C3%B6henformel#Internationale_H.C3.B6henformel&quot;&gt;German&lt;/a&gt; Wikipedia gives better values than that from the &lt;a href=&quot;http://en.wikipedia.org/wiki/Barometric_formula&quot;&gt;English&lt;/a&gt; one )&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is needed to get the density of the air, which can then be used with Archimedes' principle to get the buoyancy force of the balloon a that height.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it is stated that the formula only returns valid values for altitudes up to 11 km. Is there a way to calculate the air pressure at a higher altitude?&lt;/p&gt;&#xA;" OwnerUserId="2424" LastActivityDate="2016-11-26T11:58:15.393" Title="Pressure as a function of altitude above 11 km" Tags="|barometric-pressure|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4241" PostTypeId="2" ParentId="4239" CreationDate="2015-01-10T20:17:43.350" Score="17" Body="&lt;p&gt;Yes. Nearly global satellite and radar derived rainfall data are hosted by NASA Goddard Space Flight Center, namely:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://pmm.nasa.gov/data-access/downloads/trmm&quot;&gt;Tropical Rainfall Measurement Mission (TRMM)&lt;/a&gt; aboard the TRMM Microwave Imager (TMI), a multi-channel, dual polarized, conical scanning passive microwave radiometer designed to measure rain rates over a wide swath under the TRMM satellite. TRMM was launched on November 27, 1997 into a semi-equatorial (+/- 35 deg) orbit carrying 5 instruments. Three levels of data processing are available on the NASA's server, where higher level indicates more processing, quality control, and merging of multiple raw datasets. For your purposes, use level 3 TRMM as it combines satellite data from multiple swaths with precipitation radar data and other sources, and provide 3-hourly data in the 60S-60N latitude band, at 0.25 degree horizontal resolution.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://pmm.nasa.gov/data-access/downloads/gpm&quot;&gt;Global Precipitation Measurement&lt;/a&gt; mission was launched in early 2014, and provides full global coverage at 0.1 degree horizontal resolution at 30 minute intervals in time. This product is in its very early stages, and is still under development and testing. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In both cases, if you are interested in more precise rainfall estimates at a particular point in space and time, look at level 1 data. It is raw data that provides a time step for every single point along an orbital trajectory of the satellite. Use with caution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition, &lt;a href=&quot;http://pmm.nasa.gov/data-access/downloads/ground-validation&quot;&gt;ground validation data&lt;/a&gt; is available on the same server, and some or most of these data is assimilated (merged) into level 3 TRMM and GPM products. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once you download the data, you can use their data viewer, &lt;a href=&quot;http://pmm.nasa.gov/data-access/recipes&quot;&gt;THOR&lt;/a&gt;, or use your favorite programming language or analysis software to display it yourself.&lt;/p&gt;&#xA;" OwnerUserId="192" LastActivityDate="2015-01-10T20:17:43.350" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4242" PostTypeId="1" CreationDate="2015-01-11T05:10:15.640" Score="8" ViewCount="248" Body="&lt;p&gt;I know this sounds like a crazy observation but San Francisco has a lot of HUGE buildings in the downtown area , millions of tons or probably more. Many Scientists think a big earthquake there is 'overdue' or maybe 'delayed' for some reason. I was thinking could all the millions or billions of extra 'tonnage' of buildings that has been built over the last 20 years say, could all this 'MASSIVE' pressure on the ground in San Francisco be somehow delaying the build up of any instabilities in the underground areas ? Maybe all the massive buildings in all big cities can serve to 'dampen' any underground instability. Do Earthquakes mainly strike near areas where there are not that many MASSIVE buildings?&lt;/p&gt;&#xA;" OwnerUserId="1371" LastActivityDate="2015-01-20T12:42:17.720" Title="About Earthquakes and their properties" Tags="|seismology|earthquakes|predictability|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4243" PostTypeId="2" ParentId="4231" CreationDate="2015-01-11T07:03:55.480" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;I think that notations S$_1$, S$_2$, ..., S$_n$ may well refer to any&#xA;  ordered orogenetic phases producing schistosity in any rock, anywhere,&#xA;  at any time&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Generally, yes. This is not only true for the Alps, but also for any other orogenic regions in the world (e.g. Himalayas, Arabian-Nubian Shield). Note that the numbering is ($n$) is used very loosely. It all depends on what's observable in the studied rocks and what is the emphasis.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...when talking about S1 Alpine schistosity, or S2 Alpine schistosity,&#xA;  one usually refers to a well defined temporal phase of Alpine orogeny&#xA;  producing a particular schistous foliation. Is that so?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;For example, I've seen studies where original sedimentary foliation was termed S$_0$. In other places it was termed S$_1$. Talking about Alpine schistosities, you gave an example where S$_1$ and S$_2$ are pre-Alpine (Variscan). On the other hand, another Briançonnais study by Ganne et al (2003), refers to S$_1$ as the first true Alpine schistosity and uses S$_{-1}$ for the pre-Alpine Variscan schistosities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that the S$_{n}$ terms are used to describe schistosities. These are visual features observed in petrographic examination of rocks under the microscope. These are commonly open to interpretation and debate. You have to distinguish them from the D$_{n}$ events (deformation). S$_{n}$ features are usually used as a proxy for D$_{n}$ events, but it's not a one-to-one relationships. Let's say you know that 3 deformation events occurred in a rock. However, you can only see two schistosities. How do you call them? S$_1$ and S$_2$? What if you know that the first schistosity was erased? Do you use S$_2$ and S$_3$ then?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Again, these terms are used loosely and they may not be correlated between different areas and with time, unless mentioned explicitly in the study you are reading.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-01-11T07:03:55.480" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4244" PostTypeId="2" ParentId="4240" CreationDate="2015-01-11T07:44:22.077" Score="5" Body="&lt;p&gt;Those formulas are based on an assumption that the pressure is hydrostatic and the ideal gas law. The example given is limited to 11km but uses the tables from the &lt;a href=&quot;http://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19770009539_1977009539.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;U.S. Standard Atmosphere&lt;/a&gt; which actually go up to $1000$ km. Starting at Page 58 one can find values for pressure density and temperature above 11km. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/bk5ak.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2015-01-11T08:00:33.410" LastActivityDate="2015-01-11T08:00:33.410" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4245" PostTypeId="1" AcceptedAnswerId="4253" CreationDate="2015-01-11T08:13:22.540" Score="12" ViewCount="728" Body="&lt;p&gt;Pyrocumulus clouds often form in areas that experience prolonged fire conditions, particularly forest fires, but are also associated with volcanic eruptions and even nuclear explosions.  This question focuses on forest fire origins.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An example of what one looks from above, is below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/SuEW1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Caption: Pyrocumulus cloud, above the Oregon Gulch fire in Oregon &amp;amp; California, 2014. Aircraft is a F-15C Eagle. &lt;a href=&quot;http://en.wikipedia.org/wiki/Pyrocumulus_cloud&quot; rel=&quot;noreferrer&quot;&gt;Image source&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The general idea of how pyrocumulus clouds are formed is quite well known, and its relationship with a 'firestorm' is, in a simplistic way, is shown below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/zTAcw.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Caption: Firestorm: fire (1), updraft (2), strong gusty winds (3) (A) pyrocumulonimbus cloud.&lt;a href=&quot;http://en.wikipedia.org/wiki/Firestorm&quot; rel=&quot;noreferrer&quot;&gt;Image source&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pyrocumulus and related pyroconvective clouds have been known to have caused severe hail to fall.  An example reported in the &lt;a href=&quot;http://earthobservatory.nasa.gov/Features/PyroClouds/&quot; rel=&quot;noreferrer&quot;&gt;Earth Observatory: Russian Firestorm: Finding a Fire Cloud from Space&lt;/a&gt;, from the Canberra, Australia fires:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Called pyrocumulonimbus clouds, the clouds are capable of dangerous lightning, hail, and strong winds. One such firestorm in 2003 pelted Canberra, Australia, with large, soot-darkened hail, produced a damaging tornado&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(Point of reference: Canberra is Australia's capital city, I was there at the time).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Could graupel, or even snow, fall from pyrocumulus clouds?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(It would be good if examples from real life or models could be provided, if possible)&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-01-11T15:40:48.727" LastActivityDate="2015-01-14T07:01:02.677" Title="Snow from Fire: Could graupel, or even snow, fall from pyrocumulus clouds?" Tags="|meteorology|precipitation|clouds|snow|severe-weather|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4246" PostTypeId="2" ParentId="4240" CreationDate="2015-01-11T10:40:15.377" Score="3" Body="&lt;p&gt;The original description of the &lt;a href=&quot;https://docs.google.com/file/d/0B2UKsBO-ZMVgWG9mWEJGMlFacDQ/edit?pli=1&quot; rel=&quot;nofollow&quot;&gt;US. Standard Atmosphere 1976&lt;/a&gt; turns out to include much more and detailed information than the Wikipedia article. I've now, finally, got it working using the fixed variables $H_b$, $\rho_b$, $T_b$ and $L_b$, which determine the standard height, (air) density, temperature and lapse rate at layer $b$, respectively. A sufficient overview of those values can be found on the &lt;a href=&quot;http://en.wikipedia.org/wiki/Barometric_formula#Density_equations&quot; rel=&quot;nofollow&quot;&gt;wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This approach gives quite accurate results, which fit to the values supplied by Isopycnal Oscillation.&lt;/p&gt;&#xA;" OwnerUserId="2424" LastEditorUserId="2424" LastEditDate="2015-01-11T21:45:42.493" LastActivityDate="2015-01-11T21:45:42.493" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4247" PostTypeId="2" ParentId="2814" CreationDate="2015-01-11T21:46:03.773" Score="-3" Body="&lt;p&gt;You just need a big enough space,. and you need freezing cold air at the top of it, then warmer air at the bottom, and water vapour, that condenses. Then you might get rain, even snow forming depending on the temperatures. Is the conditions right you even get clouds. Now If you want to create a thunderstorm, you need air movement as well, upward ,downward, sideways and so on. And you defnitely need to produce hail and strong rain. In theory its probably possible, but its very very costly (you need a large scale building/hangar or dome, Nasa has one ;)) and very very expensive equipment to make it work, on the other hand once you have it, you have created something no one else has ever built) and you can control the weather in your closed environment. &lt;/p&gt;&#xA;" OwnerUserId="2429" LastEditorUserId="81" LastEditDate="2015-01-11T22:04:45.067" LastActivityDate="2015-01-11T22:04:45.067" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4248" PostTypeId="1" AcceptedAnswerId="7196" CreationDate="2015-01-12T06:44:19.397" Score="18" ViewCount="455" Body="&lt;p&gt;This question is related to and extension of my previous question which was about the methodology used to predict future climatic extremes:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/2789/what-is-the-methodology-to-analyze-future-climatic-extremes-using-the-results-of&quot;&gt;What is the methodology to analyze future climatic extremes using the results of climate models?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although the answer to that question is quite detailed and informative, it is still not clear to me &lt;strong&gt;whether the models used in global climate (GC) simulations can predict rare (~1000-year return period events)&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;I understand that if we have multi-thousand simulations, we can&#xA;calculate the 0.1% quantile, but I do not know whether the applied&#xA;models can predict rare events reliably. Under reliably, I mean that&#xA;in some alignment with the observed extremes or with the extremes&#xA;statistically inferred from the observations.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;All the papers I saw so far, which dealing with extremes due to&#xA;climate change, are considering 20-year return period events as&#xA;maximum&lt;/strong&gt; and comparing the simulations to observed quantiles. This is&#xA;one source of my suspicion regarding the reliability of GCMs.&lt;/li&gt;&#xA;&lt;li&gt;Are GCMs calibrated to observed mean or multiple quantiles? Daily,&#xA;monthly, annual, etc. averages are used? Averages of larger areas or&#xA;grid points (corresponding to the applied resolutions) are adopted in&#xA;the calibration, validation processes? What are the typically used&#xA;target parameters used in the calibrations?&lt;/li&gt;&#xA;&lt;li&gt;Here is an example to make it more clear: one wants to determine the&#xA;probability distribution function of extreme wind speed in a given&#xA;location from daily measurements/simulation results. The question: If we take one&#xA;simulation for the 1950-2000 period and assume for a moment that&#xA;model uncertainty is negligible compared to climate variability, can&#xA;we treat the simulation data as a sample with more or less equivalent&#xA;confidence than that of the actual observations, corresponding to the&#xA;same period, to infer large return period extremes?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;One way to check this is would be to compare the large return period extremes inferred from observed data and from multiple simulations, I have not seen any papers with above 20-year return level comparison yet.&#xA;I see that we cannot expect very accurate models regarding e.g. 1000-year extremes, because we cannot reliably calibrate and validate GCMs:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The available measurements are from a 100-200 year observation period (at best);&lt;/li&gt;&#xA;&lt;li&gt;We do not have too much data from different climatic conditions (there might be some phenomena which are not (or not adequately) taken into account in current models, we are somehow biased by the observed, prior 100 year conditions.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Any help, idea, reference, link are welcomed.&lt;/p&gt;&#xA;" OwnerUserId="1121" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-07-25T08:39:58.380" Title="Can climate models reliably predict meteorological extremes?" Tags="|meteorology|climate-change|precipitation|climate-models|simulation|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4249" PostTypeId="1" CreationDate="2015-01-12T12:41:15.210" Score="17" ViewCount="430" Body="&lt;p&gt;While researching Antarctic geology, I came across the term 'icequake' in the abstract to the article &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2013JF002849/abstract&quot;&gt;Seismicity within a propagating ice shelf rift: The relationship between icequake locations and ice shelf structure&lt;/a&gt; (Heeszel et al. 2014).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These events are also known as &lt;a href=&quot;http://en.wikipedia.org/wiki/Cryoseism&quot;&gt;cryoseisms&lt;/a&gt; - in reference to glaciers, the Wikipedia article describes a cryoseism as:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;a non-tectonic seismic event caused by sudden glacial movements. This movement has been attributed to a veneer of water which may pool underneath a glacier sourced from surface ice melt. Hydraulic pressure of the liquid can act as a lubricant, allowing the glacier to suddenly shift position. This type of cryoseism can be very brief, or may last for several minutes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and describe them as being able to&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;have an intensity of up to VI on the Modified Mercalli Scale&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is there a limit to how high glacial icequake magnitudes (Richter Scale) can be?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="115" LastEditDate="2015-01-14T15:10:39.790" LastActivityDate="2015-08-14T09:55:17.500" Title="How strong can a glacial icequake get?" Tags="|seismology|glaciology|antarctic|ice-sheets|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4250" PostTypeId="2" ParentId="3202" CreationDate="2015-01-12T14:13:20.480" Score="8" Body="&lt;p&gt;Unlike the East African Rift system, it is not possible to view the rifting crust of the West Antarctic Rift directly due to the extensive ice cover over the region (&lt;a href=&quot;http://geology.geoscienceworld.org/content/32/11/977.abstract&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;). However, scientists can and have inferred the nature of the rifting from other methods, including seismic, radar sounding, geodetic methods and by examining the petrology of exposed rocks in surrounding areas. Also, of significance, are observations made of glacial activity, particularly of the prominent Thwaites Glacier (&lt;a href=&quot;http://www.pnas.org/content/111/25/9070.full&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There seems to still be some uncertainty as to the nature of the current tectonic status of the West Antarctic Rift.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On one hand, observations of radar sounding and subglacial water routing at the base of the Thwaites Glacier show some melting that Schroeder et al. (2014) (&lt;a href=&quot;http://www.pnas.org/content/111/25/9070.full&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;) suggest that the melting is due to a geothermal flux that is consistent with magma migration and magmatism, they record a minimum average geothermal flux of ~114 mW/m&lt;sup&gt;2&lt;/sup&gt;, with some areas peaking at &gt;200 mW/m&lt;sup&gt;2&lt;/sup&gt;.  Petrologic observations by Martin et al. (2014 (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0024493713004143&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;) based on samples of of Cenozoic outcrops of surrounding exposed areas on the shoulder of the West Antarctic rift system suggest active rifting with mantle 'refertilisation'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, seismic observations from authors such as Lough et al. (2013) (&lt;a href=&quot;http://adsabs.harvard.edu/abs/2012AGUFM.T41B2587L&quot; rel=&quot;noreferrer&quot;&gt;4&lt;/a&gt;), match geodetic data from the POLENET (&lt;a href=&quot;http://polenet.org/?page_id=46&quot; rel=&quot;noreferrer&quot;&gt;5&lt;/a&gt;) program suggest that much of the rift is not presently active.  Although several earthquakes have been recorded in West Antarctica, very few occur in the rift itself, and these tend to be much smaller magnitude.  Lough et al. (2013) suggest that some of the shallower quakes occur due to glacial activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The seismicity further reinforces the conclusions made by Winberry and Anandakrishnan (2003) (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2003GL018001/full&quot; rel=&quot;noreferrer&quot;&gt;6&lt;/a&gt;) that the earthquake pattern suggest that the West Antarctic Rift is a dormant rift system, with a possible hotspot origin for volcanic activity occurring in the nearby Marie Byrd Land (&lt;a href=&quot;http://geology.geoscienceworld.org/content/32/11/977.abstract&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The evidence suggests that the West Antarctic Rift system is either dormant, or a very slow moving one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://geology.geoscienceworld.org/content/32/11/977.abstract&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;) Winberry and Anandakrishnan, 2004, &lt;a href=&quot;http://geology.geoscienceworld.org/content/32/11/977.abstract&quot; rel=&quot;noreferrer&quot;&gt;Crustal structure of the West Antarctic rift system and Marie Byrd Land hotspot&lt;/a&gt; &lt;em&gt;Geology&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.pnas.org/content/111/25/9070.full&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;) Schroeder et al. 2014, &lt;a href=&quot;http://www.pnas.org/content/111/25/9070.full&quot; rel=&quot;noreferrer&quot;&gt;Evidence for elevated and spatially variable geothermal flux beneath the West Antarctic Ice Sheet&lt;/a&gt;, &lt;em&gt;PNAS&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0024493713004143&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;) Martin et al. 2014, &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0024493713004143&quot; rel=&quot;noreferrer&quot;&gt;Increased mantle heat flow with on-going rifting of the West Antarctic rift system inferred from characterisation of plagioclase peridotite in the shallow Antarctic mantle&lt;/a&gt; &lt;em&gt;Lithos&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://adsabs.harvard.edu/abs/2012AGUFM.T41B2587L&quot; rel=&quot;noreferrer&quot;&gt;4&lt;/a&gt;) Lough et al. 2013, &lt;a href=&quot;http://adsabs.harvard.edu/abs/2012AGUFM.T41B2587L&quot; rel=&quot;noreferrer&quot;&gt;Subglacial volcanic seismicity in Marie Byrd Land detected by the POLENET/ANET seismic deployment&lt;/a&gt; &lt;em&gt;American Geophysical Union, Fall Meeting 2012&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://polenet.org/?page_id=46&quot; rel=&quot;noreferrer&quot;&gt;5&lt;/a&gt;) &lt;a href=&quot;http://polenet.org/?page_id=46&quot; rel=&quot;noreferrer&quot;&gt;POLENET&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2003GL018001/full&quot; rel=&quot;noreferrer&quot;&gt;6&lt;/a&gt;) Winberry and Anandakrishnan, 2003, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2003GL018001/full&quot; rel=&quot;noreferrer&quot;&gt;Seismicity and neotectonics of West Antarctica&lt;/a&gt; &lt;em&gt;Geophysical Research Letters&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="87" LastEditDate="2015-01-15T14:20:33.043" LastActivityDate="2015-01-15T14:20:33.043" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4251" PostTypeId="2" ParentId="2412" CreationDate="2015-01-12T22:33:08.860" Score="6" Body="&lt;p&gt;On the synoptic scale (thinking along the lines of cyclones, weather fronts etc.), then that's a pretty significant drop in that amount of time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A &lt;strong&gt;bomb&lt;/strong&gt; or &lt;strong&gt;explosive cycogenesis&lt;/strong&gt; in meteorological terms is defined as a drop of at least 24mb in 24 &lt;em&gt;hours&lt;/em&gt;, so your observation easily fits this description of being a significant rapid pressure change. There's a list of similar events &lt;a href=&quot;http://en.wikipedia.org/wiki/Rapid_deepening&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You ask what the significance would be at the surface, and only 80m up, which makes me think you might be talking about smaller scales (perhaps?), in which case @naught101 is right in suspecting small scale eddies from buildings could be causing the surprising readings. 80m isn't really going change the significance of an observation that much on synoptic/meso -scales.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Sources&lt;/em&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://glossary.ametsoc.org/wiki/Bomb&quot;&gt;http://glossary.ametsoc.org/wiki/Bomb&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0493%281980%29108%3C1589%3ASDCOT%3E2.0.CO%3B2&quot;&gt;Synoptic-Dynamic Climatology of the &quot;Bomb&quot;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="662" LastEditorUserId="662" LastEditDate="2015-01-12T22:45:14.707" LastActivityDate="2015-01-12T22:45:14.707" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4252" PostTypeId="2" ParentId="2820" CreationDate="2015-01-12T23:20:54.713" Score="4" Body="&lt;p&gt;The symmetry is caused by the the spherical nature of the Earth, the typical weather features that form at certain latitudes, the formation of circulation cells at specific latitude zones, and the effect of the Coriolis force on the weather systems and cloud bands within them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The latitude (and hence temperature from insolation) controls to a certain extent the broad scale atmospheric circulations. In the zone just North and South of the Equator, you find the trade winds converging towards the Equator from an easterly direction. Their direction is broadly determined by the Coriolis effect. (I think you can just make them out in the photo).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the mid-latitudes (30-60 degrees) you frequently find extratropical cyclones in both hemispheres. Their formation is beyond the scope of this brief answer (see &lt;a href=&quot;http://en.wikipedia.org/wiki/Cyclogenesis&quot; rel=&quot;nofollow&quot;&gt;Cyclogenesis&lt;/a&gt;), but they are effectively a result of consistent suitable conditions to at those specific latitudes for cyclones to form. They are noticeable in the image as being quite spiral shaped.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The symmetry of cyclonic features is perhaps most enhanced by the Coriolis effect, caused by the rotation of the Earth deflecting moving objects (the weather systems including the clouds) in the atmosphere. This (in combination with the pressure gradient force) causes the spiral-shaped features at the mid-latitudes that you can see in the image. The effect works in opposite directions in respective hemispheres, so in the North, the cloudy bands appear to be turned anticlockwise, and in the South they appear clockwise, enhancing the overall symmetries present.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is one of my favourite widgets for seeing this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://earth.nullschool.net/#current/wind/surface/level/orthographic=199.59,9.44,293&quot; rel=&quot;nofollow&quot;&gt;http://earth.nullschool.net/#current/wind/surface/level/orthographic=199.59,9.44,293&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="662" LastActivityDate="2015-01-12T23:20:54.713" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4253" PostTypeId="2" ParentId="4245" CreationDate="2015-01-13T02:43:26.913" Score="11" Body="&lt;p&gt;It is likely snowing somewhere in these clouds and graupel exist transiently on their way to becoming hail, but its not likely that you will see either at the surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can make a first order approximation of a pyrocumulus cloud by putting a very strong heat source at the surface in an environment otherwise favorable for severe convection.  What you'll observe is that parcels will easily reach the &lt;a href=&quot;https://en.wikipedia.org/wiki/Level_of_free_convection&quot;&gt;LFC&lt;/a&gt; and you will have tons of &lt;a href=&quot;https://en.wikipedia.org/wiki/Convective_available_potential_energy&quot;&gt;CAPE&lt;/a&gt; owing to the high surface temperature.  The maximum theoretical updraft velocity is a function of CAPE and so we can expect exceptionally strong updrafts.  This can be confirmed by the observation of severe hail falling from these clouds -- the weight the hailstones can attain increases with updraft velocity.  Because we can observe hail we know that normal moist processes we expect in cumulonimbus clouds are working. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In any mid-latitude cumulonimbus cloud the precipitation starts out as snow. What we experience on the ground is dependent on the temperature profile and this snow either makes it to the surface, melts to be become rain,  melts then becomes supercooled (freezing rain) or melts and refreezes (sleet).  Another option is that the precipitation sublimates or evaporates and never reaches the ground.  The fire driving the storm is likely producing a warm, dry environment at low levels and promoting evaporation of any precipitation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Graupel will exist as riming and accretion processes are at work, but because of the strong updraft you will end up with hail production and hail at the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To take this approximation into reality you also need to take into account how the fire is modifying the low and mid levels and what kind of aerosols are being emitted by the fire.  The aerosol content could play heavily into the microphysics and precipitation production, but this is not my area of expertise so I won't speculate on the possibilities.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="200" LastEditDate="2015-01-14T07:01:02.677" LastActivityDate="2015-01-14T07:01:02.677" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4254" PostTypeId="2" ParentId="2814" CreationDate="2015-01-13T03:49:39.200" Score="8" Body="&lt;p&gt;The artist &lt;a href=&quot;http://www.berndnaut.nl/index.htm&quot; rel=&quot;noreferrer&quot;&gt;Berndnaut Smilde&lt;/a&gt; regularly creates &lt;a href=&quot;http://www.slate.com/blogs/behold/2013/02/21/berndnaut_smilde_capturing_the_fleeting_moments_of_clouds_created_inside.html&quot; rel=&quot;noreferrer&quot;&gt;fairly large clouds inside buildings&lt;/a&gt;. An example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/2JdnL.jpg&quot; alt=&quot;Nimbus II, 2012 Digital C-type Print 75 x 112 cm Hotel MariaKapel, Hoorn, Netherlands&quot;&gt; &lt;em&gt;Nimbus II, 2012 Digital C-type Print 75 x 112 cm Hotel MariaKapel, Hoorn, Netherlands&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The clouds are a combination of aerogel and condensed water vapour, but I'm not sure exactly how they are made. The clouds typically only last long enough to get a couple of photos. I think the realism has a lot to do with the lighting. &lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2015-01-13T03:49:39.200" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4255" PostTypeId="2" ParentId="605" CreationDate="2015-01-13T06:37:11.073" Score="3" Body="&lt;p&gt;Following the asymptotic model developed by &lt;a href=&quot;http://earthweb.ess.washington.edu/roe/Web/GerardWeb/Publications_files/RoeBaker_PrecipPatt_JAS06.pdf&quot; rel=&quot;nofollow&quot;&gt;Roe and Baker (2006)&lt;/a&gt; there are essentially four parameters that govern the dynamics:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;$R_0 \to$ Vertically integrated condensation rate in a windward&#xA;column of air.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\Theta_{W,L} \to$ Ratio of the raindrop trajectories slope to the&#xA;orographic slopes.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\mu \to$ Ratio of mountain height to moisture scale height.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\Psi_{W,L} \to $Ratio of mountain length to the formation length&#xA;scale (of falling hydrometeors).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;What affects the amount of precipitation on the leeward flank is a combination of all these parameters, the full expression is found in &lt;a href=&quot;http://earthweb.ess.washington.edu/roe/Web/GerardWeb/Publications_files/RoeBaker_PrecipPatt_JAS06.pdf&quot; rel=&quot;nofollow&quot;&gt;Roe and Baker (2006)&lt;/a&gt; and it is rather complicated. However, if we consider the limits $\Psi_{W,L}, \Theta_{W,L} &amp;gt;&amp;gt;1$, that is, steep trajectories of falling hydrometeors and large orogen size then asymptotically we can estimate the precipitation on the windward side&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$P_w = \frac{R_0}{\mu}(1-e^{-\mu})$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and on the leeward side&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$P_L = \frac{R_0}{\Theta_L\mu}(e^{-\mu}).$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The latter says that, for large orogen size as compared to moisture scale height (large $\mu$), the precipitation on the leeward side vanishes, $P_L \to 0$. This is because on the windward flank, the average precipitation approaches a finite upper bound as it depletes all moisture in the air column.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://earthweb.ess.washington.edu/roe/Web/GerardWeb/Publications_files/RoeBaker_PrecipPatt_JAS06.pdf&quot; rel=&quot;nofollow&quot;&gt;Roe, Gerard H., and Marcia B. Baker. &quot;Microphysical and geometrical controls on the pattern of orographic precipitation.&quot; Journal of the Atmospheric Sciences 63.3 (2006): 861-880.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2015-01-13T07:10:21.967" LastActivityDate="2015-01-13T07:10:21.967" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4256" PostTypeId="2" ParentId="213" CreationDate="2015-01-13T07:58:34.483" Score="4" Body="&lt;p&gt;Just to expand on the answer by @Siv:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Previous studies have indeed suggested teleconnections between the jet stream and ENSO (for example: &lt;a href=&quot;http://dx.doi.org/10.1175%2F1520-0493%281981%29109%3C0813%3APSAPAW%3E2.0.CO%3B2&quot; rel=&quot;nofollow&quot;&gt;Horel 1981&lt;/a&gt;). Recall that, at a fundamental level, the jet stream (a westerly geostrophic wind pattern) is driven by horizontal North-South temperature gradients across cold and warm air masses (&lt;a href=&quot;https://en.wikipedia.org/wiki/Thermal_wind&quot; rel=&quot;nofollow&quot;&gt;thermal wind&lt;/a&gt;). Thus, it can be enhanced by increasing the temperature gradient of the two air masses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because winter frontal zones have characteristically larger temperature gradients than summer fronts, the jet stream is strongest during the boreal winter. It also moves equatorward to $30^o$ from its typical position in the summer of $50-60^o$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And as discussed in &lt;a href=&quot;http://journals.ametsoc.org/doi/full/10.1175/1520-0442%282002%29015%3C0399%3AACCAWT%3E2.0.CO%3B2&quot; rel=&quot;nofollow&quot;&gt;Chunzai Wang, 2002&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;During El Niño–La Niña events, the atmospheric westerly jet stream&#xA;  tends to move meridionally [...] El Niño (La Niña)&#xA;  corresponds to westerly (easterly) wind anomalies in the upper&#xA;  troposphere of the midlatitude Pacific, associated with the&#xA;  equatorward (poleward) displacement of the jet stream.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, the enhancement/reduction is due to the displacement of the jetstream and associated increase/decrease in the temperature gradient across the cold/warm air masses that are generating the jet stream in the first place.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/full/10.1175/1520-0442%282002%29015%3C0399%3AACCAWT%3E2.0.CO%3B2&quot; rel=&quot;nofollow&quot;&gt;Horel, J. D., and J. M. Wallace, 1981: Planetary-scale atmospheric phenomena associated with the Southern Oscillation. Mon. Wea. Rev, 109, 813–829.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/full/10.1175/1520-0442%282002%29015%3C0399%3AACCAWT%3E2.0.CO%3B2&quot; rel=&quot;nofollow&quot;&gt;Chunzai Wang, 2002: Atmospheric Circulation Cells Associated with the El Niño–Southern Oscillation. J. Climate, 15, 399–419&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2015-01-13T08:10:09.007" LastActivityDate="2015-01-13T08:10:09.007" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4257" PostTypeId="5" CreationDate="2015-01-13T15:51:33.377" Score="0" Body="" OwnerUserId="342" LastEditorUserId="20" LastEditDate="2015-01-25T00:59:12.150" LastActivityDate="2015-01-25T00:59:12.150" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4258" PostTypeId="4" CreationDate="2015-01-13T15:51:33.377" Score="0" Body="Precipitation is any form of moisture that falls from a cloud and reaches the ground. Precipitation can fall to the ground as rain, snow, sleet, hail, graupel... etc." OwnerUserId="342" LastEditorUserId="342" LastEditDate="2015-01-13T20:10:05.640" LastActivityDate="2015-01-13T20:10:05.640" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4259" PostTypeId="2" ParentId="4239" CreationDate="2015-01-13T17:04:27.980" Score="14" Body="&lt;p&gt;If you are looking for a dataset going back a bit further, but still sticking to satellite and radar data, &lt;strong&gt;GPCP&lt;/strong&gt; (&lt;a href=&quot;http://www.gewex.org/gpcp.html&quot;&gt;&lt;strong&gt;Global Precipitation Climatology Project&lt;/strong&gt;&lt;/a&gt;) goes back to &lt;strong&gt;1979&lt;/strong&gt;. The limitation of certain TRMM datasets, in addition to the relatively short length of the project, is that they only cover the tropics and so you lack data in the mid-latitudes and higher for a proper global analysis. Some TRMM datasets extend up to 60 degrees latitude by incorporating radar and other sources into the final product.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to go back even further (to &lt;strong&gt;1901&lt;/strong&gt; globally) the &lt;strong&gt;GPCC&lt;/strong&gt; (&lt;a href=&quot;https://climatedataguide.ucar.edu/climate-data/gpcc-global-precipitation-climatology-centre&quot;&gt;&lt;strong&gt;Global Precipitation Climatology Centre&lt;/strong&gt;&lt;/a&gt;) is a good place to start. Anything before the launch of TRMM in 1997 will likely be a collation of various data sets, so the comparability between regions is occasionally questionable, although there are robust ways of correcting for this applied to the datasets. This is a truly global data set, according to their spatial coverage description (90.0N - 90.0S, 0.0E - 360.0E) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Beyond that, the datasets are patchy between different countries. You would have to collate your own global dataset from the various national meteorological archives. The UK precipitation archives (&lt;a href=&quot;http://climate.arm.ac.uk/calibrated/rain/&quot;&gt;Armagh Observatory&lt;/a&gt;), for example, go back to about 1795, but I'm not aware of them being included in many (any?) global collations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;N.B. Almost all of this data will be in some form of Cartesian or geographic co-ordinate format, so you probably won't be able to look up individual places or countries, but will need to extract latitude and longitude bounded regions from the data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Link to the GPCC download site:&#xA;&lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/gridded/data.gpcc.html&quot;&gt;GPCC gridded data download&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="662" LastEditorUserId="662" LastEditDate="2015-01-13T18:04:09.790" LastActivityDate="2015-01-13T18:04:09.790" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4260" PostTypeId="2" ParentId="2814" CreationDate="2015-01-13T22:29:13.160" Score="8" Body="&lt;p&gt;Yes it is possible to build a structure similar to what you describe, and this is exactly what some researchers use to study cloud formation and the processes that operate within them. The other answers and comments have established that re-creating full-scale weather systems is probably out of the question, but &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Meteorological_cloud_chamber&quot; rel=&quot;noreferrer&quot;&gt;&lt;strong&gt;meteorological cloud chambers&lt;/strong&gt;&lt;/a&gt; exist for recreating certain weather phenomena. You ask about &lt;em&gt;&quot;preferably consumer grade&quot;&lt;/em&gt; examples, but since all of these types of apparatus are effectively custom built to an extent, you could potentially create a &quot;consumer-grade&quot; version (just don't necessarily expect research grade data from your efforts!).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From a research point of view, they are used mainly for studying microphysical processes within clouds: condensation of ice nuclei, chemical interactions between molecules in clouds, snow formation, ice-crystal riming, thunderstorm electrification, and so on. As you point out in the question, the down-scaling issue means they aren't suited to reproducing large-scale weather features, although the limit is as big as you care to build it I suppose...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a link to a &lt;a href=&quot;http://data.cas.manchester.ac.uk/micc/micc.htm&quot; rel=&quot;noreferrer&quot;&gt;research grade ice cloud chamber&lt;/a&gt;, used at the University of Manchester, UK. There are some excellent photos of how it is put together (unfortunately I don't have permission to put them here). Essentially it is a 10m tall steel chamber, which can be cooled down to about -55 centigrade. The pressure can be lowered to simulate conditions in the upper troposphere (about 50hPa). It has been used on occasion to reproduce the conditions in thunderstorm electrification. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a video of a &lt;a href=&quot;http://commons.wikimedia.org/wiki/File%3AHome_Made_Cloud_Chamber.webm&quot; rel=&quot;noreferrer&quot;&gt;home-made cloud chamber in action&lt;/a&gt; (again, it is imitating small scale features and processes in clouds, not weather systems per se.), and a simple diagram of how it is set up:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/SapZE.jpg&quot; alt=&quot;Cloud chamber diagram&quot;&gt;&lt;em&gt;Alcohol is used here, since it evaporates and condenses much more readily than water. The dry ice at the base cools the lower section of the chamber, creating a temperature gradient within the chamber. The alcohol droplets will evaporate from the strips forming a fog (cloud) at the top, then condense as they hit the cool air, forming gentle rain droplets nearer the base. Here's a link to &lt;a href=&quot;http://www.amnh.org/education/resources/rfl/web/einsteinguide/activities/cloud.html&quot; rel=&quot;noreferrer&quot;&gt;more detailed instructions.&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Something in between these kind of set-ups is the closest you will come to re-creating 'real' clouds at home. They won't have the beauty of a towering cumulus over a mountain range (although some say there is beauty in cloud microphysical processes.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Annecdote 1&lt;/em&gt;: At the EGU 2014 Annual Conference in Vienna, the organisers &lt;a href=&quot;https://twitter.com/samillingworth/status/461770646486523904/photo/1&quot; rel=&quot;noreferrer&quot;&gt;created a series of rooms&lt;/a&gt; that you could walk through and experience being inside a cloud. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Annecdote 2&lt;/em&gt;: Incidentally the first person to create a 'weather chamber' was &lt;a href=&quot;http://en.wikipedia.org/wiki/Charles_Thomson_Rees_Wilson&quot; rel=&quot;noreferrer&quot;&gt;CTR Wilson&lt;/a&gt;, trying to reproduce the cloud formations he had seen on Ben Nevis in the Scottish Highlands. His invention actually led to the discovery of ionizing radiation. &#xA;&lt;a href=&quot;http://www-outreach.phy.cam.ac.uk/camphy/cloudchamber/cloudchamber_index.htm&quot; rel=&quot;noreferrer&quot;&gt;http://www-outreach.phy.cam.ac.uk/camphy/cloudchamber/cloudchamber_index.htm&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="662" LastEditorUserId="662" LastEditDate="2015-01-13T22:34:33.510" LastActivityDate="2015-01-13T22:34:33.510" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4261" PostTypeId="1" CreationDate="2015-01-13T22:57:35.130" Score="9" ViewCount="1029" Body="&lt;p&gt;Often, in texts (particularly for schools etc) depict a smooth spherical isotropic boundary between the inner and outer core, as shown in the image from &lt;a href=&quot;http://geomaps.wr.usgs.gov/parks/pltec/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this USGS public education page&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/fORy6.gif&quot; alt=&quot;enter image description here&quot;&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The inner core boundary is between the inner and outer core layers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How isotropic is the Earth's inner core boundary?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Related questions&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/517/how-can-we-guess-the-size-of-the-earths-inner-coreand-what-its-made-of&quot;&gt;How can we guess the size of the Earth's inner core(and what it's made of)?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/2866/why-does-seismic-activity-shed-light-on-the-inner-core-rigidity&quot;&gt;Why does seismic activity shed light on the inner core rigidity?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/526/why-is-earths-inner-core-solid&quot;&gt;Why is Earth's inner core solid?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are related but this question is about the nature of the boundary between the inner and outer core.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-01-14T00:57:22.653" Title="How isotropic is the Earth's inner core boundary?" Tags="|geophysics|core|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4262" PostTypeId="2" ParentId="4261" CreationDate="2015-01-13T22:57:35.130" Score="10" Body="&lt;p&gt;Some recent geophysical observations by Dai et al. (2012) (&lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356661/&quot;&gt;1&lt;/a&gt;) showed that compressional seismic waves reflected off the inner core boundary (ICB) exhibit significant variations in:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;travel time, of the order of -2 to 2.5 seconds.&lt;/li&gt;&#xA;&lt;li&gt;amplitude, by up to a factor greater than 4 (up to a factor of 6 oberved by Li et al. 2014 (&lt;a href=&quot;http://link.springer.com/article/10.1007/s11589-014-0093-9&quot;&gt;2&lt;/a&gt;)).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;These observations, according to Dai et al. (2012) (&lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356661/&quot;&gt;1&lt;/a&gt;) suggest that the ICB is irregular, with possible height differences of up to 14 km, across a distance of 6 km, and 4-8 km over a distance of 2-4 km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Dai et al. (2012) (&lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356661/&quot;&gt;1&lt;/a&gt;) suggest that these variations are indicative of thermochemical deformation of the ICB. An alternative explanation presented by Li et al. (2014) (&lt;a href=&quot;http://link.springer.com/article/10.1007/s11589-014-0093-9&quot;&gt;2&lt;/a&gt;), after numerical analyses of seismic traces, taking into account the effects of shallower structures, suggest that the ICB being a several-kilometre-thick 'mushy' layer indicative of a gradual transition between the inner and outer core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The actual nature of the ICB is not completely understood, a recent theory by Vamos and Suciu (2014) (&lt;a href=&quot;http://arxiv.org/pdf/1402.6494v1.pdf&quot;&gt;3&lt;/a&gt;) suggest that the anisotropy of seismic observations could be a result of a de-centred core due to interactions with the flow and the magnetic field inside the outer core. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Observations by Wen (2006) (&lt;a href=&quot;http://www.sciencemag.org/content/314/5801/967.short&quot;&gt;4&lt;/a&gt;) found that seismic traces from the same location taken at different times posessed different return times in the space of ~10 years, suggesting that deformations (as later described by Dai et al (&lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356661/&quot;&gt;1&lt;/a&gt;)) occur on a differentially rotating inner core, alternatively, Wen (&lt;a href=&quot;http://www.sciencemag.org/content/314/5801/967.short&quot;&gt;4&lt;/a&gt;) suggests that the size of the inner core changes with time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356661/&quot;&gt;1&lt;/a&gt;) Dai et al. 2012, &lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3356661/&quot;&gt;Irregular topography at the Earth’s inner core boundary&lt;/a&gt;, &lt;em&gt;PNAS&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://link.springer.com/article/10.1007/s11589-014-0093-9&quot;&gt;2&lt;/a&gt;) Li et al. 2014, &lt;a href=&quot;http://link.springer.com/article/10.1007/s11589-014-0093-9&quot;&gt;Notes on the variability of reflected inner core phases&lt;/a&gt;, &lt;em&gt;Earthquake Science&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://arxiv.org/pdf/1402.6494v1.pdf&quot;&gt;3&lt;/a&gt;) Vamos and Suciu 2014, &lt;a href=&quot;http://arxiv.org/pdf/1402.6494v1.pdf&quot;&gt;Geophysical implications of a decentered inner core&lt;/a&gt;, &lt;em&gt;arXiv.org&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.sciencemag.org/content/314/5801/967.short&quot;&gt;4&lt;/a&gt;) Wen 2006, &lt;a href=&quot;http://www.sciencemag.org/content/314/5801/967.short&quot;&gt;Localized Temporal Change of the Earth's Inner Core Boundary&lt;/a&gt;, &lt;em&gt;Science&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2015-01-13T22:57:35.130" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4263" PostTypeId="2" ParentId="2114" CreationDate="2015-01-14T05:17:31.313" Score="7" Body="&lt;p&gt;I assume you are talking about the fluid dynamics description of flux, which is the rate of volume flow across a unit area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;1.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is flux simply specific discharge × area?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes you are correct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$Specific~Discharge = \frac{Volumetric~Flux}{Area}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;therefore&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$Volumetric~Flux = Specific~Discharge~\cdot~Area$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;2.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;And when we speak of flux of an element eg. N-flux, is that specific&#xA;  discharge × concentration × area?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;When you speak of an element the rationale is the same but will depend on whether the model you are devising contains 1D, 2D or 3D fluid elements. The latter is defined as above.&lt;/p&gt;&#xA;" OwnerUserId="200" LastActivityDate="2015-01-14T05:17:31.313" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4264" PostTypeId="2" ParentId="2257" CreationDate="2015-01-14T06:06:52.363" Score="13" Body="&lt;p&gt;This is my favorite example of the difference between a hydrostatic and a non-hydrostatic code. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The simulation depicts a lock exchange which you can picture as opening your window if you live in a cold place and it is winter. Inside your house, presumably, the air is warmer than the outside. So when you open the window, the cooler (heavier) air will descend and spill inside the house underneath the warm (lighter) air which will spill outside your house.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this simulation there are two fluids with different densities initially separated by a vertical imaginary gate (lock) at the center of the domain which is &quot;removed&quot; when the simulation begins. The heavier (colder) fluid is on the right and moves to the left under the lighter (warmer) fluid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because the hydrostatic simulation does not use the momentum equation in the vertical direction, it is not able to capture features for which the horizontal and vertical length scales are on the same order of magnitude. In this example, despite the resolution being the same between (a) and (b), only the non-hydrostatic code is able to capture the Kelvin-Helmholtz billows. However, the hydrostatic code can also be valuable. In this case, it is 8 times faster and it captures the large scale features of the flow such as the bore speed and interface thickness.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/mP0xV.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2015-01-14T20:00:52.023" LastActivityDate="2015-01-14T20:00:52.023" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4266" PostTypeId="2" ParentId="2530" CreationDate="2015-01-14T22:05:19.980" Score="9" Body="&lt;p&gt;Be warned this is a general (and speculative) answer, but it was getting too long to be a comment: The bulk of Greenland's ice mass is centred over inland/central Greenland. If you were to take all the ice away today, much of central Greenland would actually be below sea level, by several hundred metres in fact:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/XQPrwl.jpg&quot; alt=&quot;Greenland without ice&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Glacial isostatic rebound would seek to equilibrate the loss in mass by 'popping' Greenland back up, but it appears that we'd be starting from at or below sea level over much of the island! I'm afraid I don't have any figures to hand over what the total isostatic adjustment might be in the centre, but I would be skeptical of it producing peaks any higher than the current ice sheet level - so the net effect on atmospheric circulation in this region may be small.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Interestingly, the post-glacial isostatic adjustment going on in that region is not as simple as may be expected, some areas over Greenland are actually still sinking, due in part to the movement of former ice mass from the Arctic into the seas around Greenland (as water). The figure below indicates that the areas to watch are actually Canada and Scandinavia, at least for now.&#xA;&lt;img src=&quot;https://i.stack.imgur.com/QYTBt.png&quot; alt=&quot;Isostatic adjustments globally&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the existing tall peaks that &lt;em&gt;are&lt;/em&gt; rebounding, in general terms you could potentially expect more orographic precipitation enhancement as they became higher, more erosion, which could lead to greater drawdown of CO2 from weathering...the arm-waving speculation goes on... (&lt;a href=&quot;https://earthscience.stackexchange.com/questions/58/what-is-the-status-of-the-raymo-ruddiman-idea-that-tibet-cooled-the-earth&quot;&gt;but see this question&lt;/a&gt;.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From a regional climate aspect, I would perhaps be more concerned over the decrease in albedo on Greenland from the loss of its ice cap. Also, the potential effect of changing surface moisture fluxes to the atmosphere, should central Greenland end up becoming a series of lakes and islands (rather like Finland in its post-glacial state today).&lt;/p&gt;&#xA;" OwnerUserId="662" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-01-15T12:48:03.913" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4267" PostTypeId="2" ParentId="2355" CreationDate="2015-01-15T03:38:01.607" Score="6" Body="&lt;p&gt;This answer is probably a bit speculative, but looks at the 'cryolithology' of the region where these craters occurred, especially given the recent images from scientific exploration of these craters, as reported in news sources such as Austraia's Daily Mail article &lt;a href=&quot;http://www.dailymail.co.uk/sciencetech/article-2831238/Descending-depths-Siberia-s-mystery-crater-Experts-explore-98ft-wide-hole-learn-origins.html&quot;&gt;Descending into the depths of Siberia's mystery crater: Experts explore 98ft-wide hole to learn more about its origins&lt;/a&gt;.  There is a suggestion that the formation may be due to the formation of a &lt;a href=&quot;http://en.wikipedia.org/wiki/Pingo&quot;&gt;pingo&lt;/a&gt; as opposed to a methane eruption.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Irrespective of the cause, it is reasonably clear that something 'erupted' from the subsurface, forming the crater.  This answer will focus not on the cause, but to answer the question what could have resulted in the smooth walls.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clues to how the craters have smooth walls and rugged crater surface features come from both the cryolithology of the Yamal Peninsula (where these craters are, according to the article linked in the question) and from the observations in the articles themselves. The Yamal Peninsula possesses an extensive permafrost.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the Yamal Peninsula is an area rich in hydrocarbon deposits that are being extracted, one of the best insights to the cryolithology of the region is from exploration observations.  According to the article &lt;a href=&quot;http://www.searchanddiscovery.com/abstracts/html/2013/90177arctic/abstracts/strel.htm&quot;&gt;Genesis of Methane Entrapped in Ground Ice, Yamal Peninsula, WS Russia&lt;/a&gt; (Streletskaya, 2013), the sediments  contain ground ice bodies and icy sediments with between 50-95% volumetric ice content.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the Smithsonian webpage &lt;a href=&quot;http://www.mnh.si.edu/arctic/html/yamalex.html&quot;&gt;about a Yamal expedition&lt;/a&gt;, these sediments consist of clay, silt, sand and mud - and very rarely are there any rocks greater than the size of pebbles.  Effectively frozen and depending on the ambient air temperature, semi-frozen-mud-slush.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, the sediments would behave like mud, and the ice content would have held the sediments together to make the smooth walls, particularly in the absence of rocks to scour the walls.  The ice in the sediments in the exposed areas, particularly on the surface would have melted, forming the drainage rivulets in the picture in the question.  The article does mention that there were trickles of water down the sides, suggesting that the crater wall were also beginning to melt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The articles also suggest this by stating that attempts to descent into the crater were successfully performed in winter, as the ground is hard (= frozen).&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-01-15T03:45:20.820" LastActivityDate="2015-01-15T03:45:20.820" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4268" PostTypeId="2" ParentId="3201" CreationDate="2015-01-15T13:45:27.503" Score="5" Body="&lt;p&gt;&lt;strong&gt;Lyle et al. (2007)&lt;/strong&gt;, prior to the paper you mention, also came up with this idea that the ACC initiated &lt;em&gt;with its modern setting&lt;/em&gt; (i. e. with strong currents and mixing throughout the water column)  during the Late Oligocene (ca. 25 Ma), so roughly 10 Myr after the Eocene-Oligocene when the antarctic glaciation is thought to have occurred. Their evidence is based on sedimentology, specifically the presence of erosional structure associated with deep current flow. They however don't discard in this paper the idea that a &lt;em&gt;surface&lt;/em&gt; ACC existed prior to this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The original idea (&lt;strong&gt;Kennett 1977&lt;/strong&gt;) according to which the ACC started near the Eocene-Oligocene transition was based on the observation of biogenic sedimentary facies pattern (classically siliceous south of the ACC and carbonaceous north) coupled with the observation of the opening of the Drake Passage around that time. Later, observations of the establishment of an endemic antarctic planktonic fauna during the latest Eocene (e. g. &lt;strong&gt;Lazarus &amp;amp; Caulet 1993&lt;/strong&gt;, &lt;strong&gt;Lazarus et al. 2008&lt;/strong&gt;) and measurement of Nd isotopes (&lt;strong&gt;Scher &amp;amp; Martin, 2006&lt;/strong&gt;) at Agulhas Ridge (i. e. south of Africa) that coincides with Pacific waters values strengthened that hypothesis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the idea that the antarctic glaciation was a consequence of the setting of the ACC has been somewhat challenged (&lt;strong&gt;De Conto &amp;amp; Pollard, 2003&lt;/strong&gt;, and later &lt;strong&gt;Barker &amp;amp; Thomas, 2004&lt;/strong&gt;) based mainly on numerical modeling, as they show that, although a developed ACC would have participated in the cooling triggering the glaciation, it is not a necessary condition for it: the glaciation could have entirely been caused by the observed drop of atmospheric $p_\mathrm{CO_2}$, even without a developed ACC.&lt;br&gt;&#xA;Additionally, some of the evidences for an early setting of the ACC (namely the facies change argument) could very well be a consequence of the glaciation rather than the consequence of the ACC (&lt;strong&gt;Barker &amp;amp; Thomas, 2004&lt;/strong&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, as far as I see, we are at a stand-off, where we have arguments in favor of a late settling of the ACC (mostly sedimentary and tectonic arguments) and at the same time arguments in favor of an early settling (in particular paleontological and geochemical arguments) and no real reason to discard any.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;References:&lt;br&gt;&#xA;Barker &amp;amp; Thomas, 2004. &lt;a href=&quot;http://dx.doi.org/doi:10.1016/j.earscirev.2003.10.003&quot; rel=&quot;nofollow&quot;&gt;Origin, signature and palaeoclimatic influence of the Antarctic Circumpolar Current.&lt;/a&gt; Earth-Science Reviews, 66: 143-162.&lt;br&gt;&#xA;De Conto, R.M., Pollard, D., 2003. &lt;a href=&quot;http://www.nature.com/nature/journal/v421/n6920/abs/nature01290.html&quot; rel=&quot;nofollow&quot;&gt;Rapid Cenozoic glaciation of Antarctica induced by declining atmospheric $\mathrm{CO_2}$&lt;/a&gt;. Nature 421, 245 – 249.&lt;br&gt;&#xA;Kennett, J.P., 1977. Cenozoic evolution of Antarctic glaciation, the circum-Antarctic Ocean, and their impact on global paleoclimate. Journal of Geophysical Research, 82: 3843–3860.&lt;br&gt;&#xA;Lazarus, D. B. &amp;amp; J.-P. Caulet, 1993. Cenozoic Southern Ocean reconstructions from sedimentologic, radiolarian and other microfossil data. In J. P. Kennett and D. A. Warnke (Eds), The Antarctic Paleoenvironment: a perspective on global change. Antarctic Research Series, 60: 145-174.&lt;br&gt;&#xA;Lazarus, D. B. et al., 2008. Patterns of opal and radiolarian change in the Antarctic mid-Paleogene: clues to the origin of the Southern Ocean. Micropaleontology, 54(1): 41-48.&lt;br&gt;&#xA;Lyle et al., 2007. &lt;a href=&quot;http://dx.doi.org/10.1130/G23806A.1&quot; rel=&quot;nofollow&quot;&gt;Late Oligocene initiation of the Antarctic Circumpolar Current: Evidence from the South Pacific&lt;/a&gt;. Geology, 35: 691-694.&lt;br&gt;&#xA;Scher, H. D. &amp;amp; Martin, E. E.,  2006. &lt;a href=&quot;http://dx.doi.org/10.1126/science.1120044&quot; rel=&quot;nofollow&quot;&gt;Timing and Climatic Consequences of the Opening of Drake Passage.&lt;/a&gt; Science, 312: 428-430.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2015-01-15T14:15:22.960" LastActivityDate="2015-01-15T14:15:22.960" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4269" PostTypeId="1" CreationDate="2015-01-15T15:01:08.773" Score="7" ViewCount="199" Body="&lt;p&gt;NASA GLAS Lidar Data can be downloaded &lt;a href=&quot;http://nsidc.org/data/icesat/data.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I cannot find (or perhaps understand) the answer to my question on the icesat/glas page.  Lidar data can be provided as points (las) or raster (dem), though I believe either could be packaged as HDF5 (what they offer).  They list a number of parameters which makes it sound like it's points, but then they compare results with an SRTM dem.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anybody know what you get with this download? &lt;/p&gt;&#xA;" OwnerUserId="2440" LastEditorUserId="5594" LastEditDate="2016-12-02T12:31:51.603" LastActivityDate="2016-12-02T12:31:51.603" Title="NASA GLAS Lidar Data Format" Tags="|remote-sensing|land-surface|data-formats|" AnswerCount="0" CommentCount="10" ClosedDate="2016-12-04T21:36:40.750" ContentLicense="CC BY-SA 3.0" />
  <row Id="4270" PostTypeId="2" ParentId="4239" CreationDate="2015-01-15T15:11:02.203" Score="8" Body="&lt;p&gt;&lt;a href=&quot;http://www.worldclim.org&quot;&gt;WorldClim&lt;/a&gt; is an alternative. It is a set of climate layers with spatial resolution of 1 square kilometer. It provides current conditions, forecast and historical data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Besides rainfall there are data available for Min. Temperature, Temperature, Mean Temperature, Bioclim and Altitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Data is divided in tiles and available in GeoTiff or ESRI grid format.&lt;/p&gt;&#xA;" OwnerUserId="2439" LastActivityDate="2015-01-15T15:11:02.203" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4271" PostTypeId="1" AcceptedAnswerId="4444" CreationDate="2015-01-15T18:13:21.670" Score="9" ViewCount="127" Body="&lt;p&gt;The Antarctic Circumpolar Current (ACC), the oceanic current that flows around the Antarctic continent, has many links to weather and climate processes (e.g., &lt;a href=&quot;https://earthscience.stackexchange.com/questions/3201/is-there-conclusive-evidence-for-the-antarctic-circumpolar-current-developing-af&quot;&gt;Is there conclusive evidence for the Antarctic Circumpolar Current developing after the glaciation of Antarctica?&lt;/a&gt;).&#xA;My question is how has the total transport of the current changed in time at different time scales? Clearly, it has changed since its potential formation in the late Miocene. My interest is in both short time scales (seasonal), decadal (e.g., ENSO effects) and longer time scales.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-02-24T09:19:04.620" Title="How much has the total transport of the Antarctic Circumpolar Current changed over time?" Tags="|ocean|oceanography|ocean-currents|antarctic|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4272" PostTypeId="1" AcceptedAnswerId="5202" CreationDate="2015-01-15T20:26:11.897" Score="9" ViewCount="881" Body="&lt;p&gt;There was no geography site on Stack Exchange, so I thought the best place to ask about this was in Earth Science: Do we have an estimate for the length of the American Cordillera (the chain of mountain ranges in the west of the Americas, reaching from Alaska down to Antarctica)? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried calculating it by using the lengths of the mountain ranges listed on the Wikipedia page, but some mountain ranges don't have a length recorded anywhere. The best I could get was a rough estimate of about 8500 miles, the length of the Alaska Range, the Coast Mountains in British Columbia, the Cascade Range, the Sierra Nevada, the Sierra Madre Occidental, the Baja California peninsula, and the Andes. The Sierra Madre de Chiapas, COrdillera Central, and Graham Land had no length to add, and maps were no help.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does a record exist for this lengthy range, or did no one ever bother?&lt;/p&gt;&#xA;" OwnerUserId="2443" LastActivityDate="2015-07-18T01:27:52.440" Title="Is there an estimate for the length of the American Cordillera?" Tags="|mountains|geography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4273" PostTypeId="1" CreationDate="2015-01-15T20:33:03.987" Score="19" ViewCount="4963" Body="&lt;p&gt;There are quite a few things which can make an otherwise habitable planet uninhabitable, and some of these will eventually happen, sooner or later:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;engulfed by its star when it becomes a red giant&lt;/li&gt;&#xA;&lt;li&gt;destroyed by the nova or supernova of its star&lt;/li&gt;&#xA;&lt;li&gt;loses its magnetosphere and the solar wind blows its atmosphere away&lt;/li&gt;&#xA;&lt;li&gt;collides with a large enough object&lt;/li&gt;&#xA;&lt;li&gt;gamma ray burst&lt;/li&gt;&#xA;&lt;li&gt;maybe other astronomical phenomena?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;some of these will inevitably happen to Earth in the future, but which one is to be expected to happen sooner? By uninhabitable I mean uninhabitable to currently known multicellular life.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the sake of this question, assume that humans don't invent technology in the future which would stop this from happening, and also no extraterrestrial visitors, supernatural forces or similar effects intervene. Actually, let's assume that humans magically vanish today, just to not get distracted by the effects of human technology.&lt;/p&gt;&#xA;" OwnerUserId="2442" LastEditorDisplayName="user889" LastEditDate="2015-01-15T21:48:26.917" LastActivityDate="2015-02-24T03:41:37.933" Title="What would be the first thing which will render the Earth uninhabitable?" Tags="|geophysics|hypothetical|" AnswerCount="4" CommentCount="14" ContentLicense="CC BY-SA 3.0" />
  <row Id="4274" PostTypeId="2" ParentId="4273" CreationDate="2015-01-15T22:00:50.827" Score="23" Body="&lt;p&gt;I'll try to put time scales on each of these events.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;The Sun as a red giant - 5 to 6 billion years&lt;/strong&gt;$^1$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Sun is currently on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Main_sequence&quot; rel=&quot;nofollow noreferrer&quot;&gt;main sequence&lt;/a&gt;, which means that it's a &quot;full grown&quot; star - think of it as being middle-aged. It's been on the main sequence for around 4 to 5 billion years, and in 5 to 6 billion years, it will leave the main sequence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most yellow (i.e. &lt;a href=&quot;https://en.wikipedia.org/wiki/G-type_main-sequence_star&quot; rel=&quot;nofollow noreferrer&quot;&gt;spectral class G-ish&lt;/a&gt;) stars spend about 10 billion years on the main sequence. Then, they swell up as &lt;a href=&quot;https://en.wikipedia.org/wiki/Red_giant&quot; rel=&quot;nofollow noreferrer&quot;&gt;red giants&lt;/a&gt;. The Sun is just over halfway through the main sequence, so it has about 5 to 6 billion years left. After 5.4 billion years, it will grow. Here's an image showing how its radius (and other factors) will increase:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/6/6c/Solar_evolution_%28English%29.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/6/6c/Solar_evolution_%28English%29.svg&quot; alt=&quot;Future of the Sun&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Sun won't swallow the inner planets up right away - see how it takes a while for it to grow - but it will happen eventually. It will take another billion years to reach a radius 200 times that of its current size. It will enter the &lt;a href=&quot;https://en.wikipedia.org/wiki/Asymptotic_giant_branch&quot; rel=&quot;nofollow noreferrer&quot;&gt;AGB phase&lt;/a&gt;, where it will finally grow enough to swallow the inner planets. It's uncertain as to whether or not Earth will be destroyed, but it will be heated up so much that liquid water will disappear and the planet will be uninhabitable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://science.nasa.gov/science-news/science-at-nasa/2012/25oct_friedplanets/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA&lt;/a&gt; has an article on a Sun-like star swallowing up one of its inner planets, just as the Sun may do. The original paper can be found &lt;a href=&quot;http://arxiv.org/pdf/1206.4938.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Supernova/nova - Never&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two types of supernovae: &lt;a href=&quot;https://en.wikipedia.org/wiki/Type_II_supernova&quot; rel=&quot;nofollow noreferrer&quot;&gt;Type II&lt;/a&gt; and Type I. Type II supernovae are characterized by hydrogen; Type I supernovae have no hydrogen. You've probably heard of Type II supernovae when you learned about supernovae, and they're the more well-known. They're the result of the collapse of the core of a massive star. However, the progenitor, has t be much larger than the Sun - usually at least 8 solar masses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Type I supernovae have no hydrogen. There are two main classes: &lt;a href=&quot;https://en.wikipedia.org/wiki/Type_Ia_supernova&quot; rel=&quot;nofollow noreferrer&quot;&gt;Type Ia&lt;/a&gt; and Type Ib/c. The first category are the result of white dwarfs accreting mass from a companion star. The Sun has no binary companion, so even though it will become a white dwarf, it will never undergo this kind of supernova. &lt;a href=&quot;https://en.wikipedia.org/wiki/Type_Ib_and_Ic_supernovae&quot; rel=&quot;nofollow noreferrer&quot;&gt;Type Ib/c&lt;/a&gt; also result from core collapse, just like Type II. However, their progenitors are unstable, violent stars, typically &lt;a href=&quot;https://en.wikipedia.org/wiki/Wolf%E2%80%93Rayet_star&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wolf-Rayet stars&lt;/a&gt;. Our Sun will fortunately never become one of those!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A &lt;a href=&quot;https://en.wikipedia.org/wiki/Nova&quot; rel=&quot;nofollow noreferrer&quot;&gt;nova&lt;/a&gt; is small compared to a supernova. It, like Type Ia supernovae, may be the result of a white dwarf accreting matter from a companion. Once again, though, the Sun has no companion star to accrete matter from.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Magnetosphere loss - Never&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth's &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_magnetic_field&quot; rel=&quot;nofollow noreferrer&quot;&gt;magnetic field&lt;/a&gt; is very important, because it shields us from the solar wind. Without it, life on Earth probably couldn't exist! Its disappearance would not be good for us.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fortunately, it doesn't appear that that will ever happen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth's magnetic field is believed to be caused by the movement of fluids in Earth's core. Wikipedia lists three conditions necessary for the existence of the magnetic field:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ol&gt;&#xA;  &lt;li&gt;&lt;p&gt;An electrically conductive fluid medium&lt;/p&gt;&lt;/li&gt;&#xA;  &lt;li&gt;&lt;p&gt;Kinetic energy provided by planetary rotation&lt;/p&gt;&lt;/li&gt;&#xA;  &lt;li&gt;&lt;p&gt;An internal energy source to drive convective motions within the fluid.&lt;/p&gt;&lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The fluid in the Earth's core will never go away, and so long as the planet keeps rotating, that kinetic energy will always be there. So will the &lt;a href=&quot;https://en.wikipedia.org/wiki/Coriolis_effect&quot; rel=&quot;nofollow noreferrer&quot;&gt;Coriolis effect&lt;/a&gt;, which also helps circulate the fluid and control the magnetic field. The source of the energy that keeps the material hot is due in part to &lt;a href=&quot;https://en.wikipedia.org/wiki/Tidal_force&quot; rel=&quot;nofollow noreferrer&quot;&gt;tidal forces&lt;/a&gt; between the Earth and other bodies, such as the Moon and the Sun.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Collision - Not for a long time&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth has had one major collision throughout its life, and that spawned the moon. This idea is known as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Giant_impact_hypothesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;giant impact hypothesis&lt;/a&gt;. When the solar system - and Earth - was young, the Sun had a disk of small pre-planetary bodies, known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Protoplanet&quot; rel=&quot;nofollow noreferrer&quot;&gt;protoplanets&lt;/a&gt;. There were more protoplanets than there are planets today, because many collided to form the planets.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The hypothesized protoplanet, named &lt;a href=&quot;https://en.wikipedia.org/wiki/Theia_(planet)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Theia&lt;/a&gt;, is generally described as Mars-like. It didn't hit the Earth head-on, but rather hit it an a 45 degree angle. The result was that Theia was destroyed and some of Earth was ejected. Much of this material came back to Earth, but some stayed and formed the Moon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There aren't any more protoplanets, but there are still some large asteroids. The biggest is &lt;a href=&quot;https://en.wikipedia.org/wiki/Ceres_(dwarf_planet)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ceres&lt;/a&gt;, which is &lt;em&gt;tiny&lt;/em&gt; compared to Theia. Here's a picture of Earth, the Moon and Ceres (bottom left):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/1/16/Ceres_Earth_Moon_Comparison.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/1/16/Ceres_Earth_Moon_Comparison.png&quot; alt=&quot;Earth, Moon and Ceres&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We're not likely to see another giant impact again. The other planets all have stable orbits, and the Moon's actually receding from Earth due to tidal forces. Sure, &lt;a href=&quot;https://en.wikipedia.org/wiki/Impact_event#Frequency_and_risk&quot; rel=&quot;nofollow noreferrer&quot;&gt;asteroid impacts&lt;/a&gt; are a possibility, but the possibility of a doomsday asteroid is tiny. Even a body like the one that killed the dinosaurs wouldn't extinguish &lt;em&gt;all&lt;/em&gt; life. &lt;a href=&quot;http://www.jpl.nasa.gov/asteroidwatch/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Jet Propulsion Laboratory&lt;/a&gt; has information on the likelihood of such a catastrophic event (not a high one!).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Gamma-ray burst - Probably never&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I wrote &lt;a href=&quot;https://astronomy.stackexchange.com/questions/2585/how-likely-and-severe-is-the-threat-of-a-gamma-ray-burst-to-earth&quot;&gt;an answer&lt;/a&gt; on Astronomy about this a while ago. If I may, I'll quote from that answer:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Okay, back to the topic at hand. Wikipedia, of course, has a short tidbit on the frequency of gamma-ray bursts effecting Earth:&lt;/p&gt;&#xA;  &#xA;  &lt;blockquote&gt;&#xA;    &lt;p&gt;Estimating the exact rate at which GRBs occur is difficult, but for a galaxy of approximately the same size as the Milky Way, the expected rate (for long-duration GRBs) is about one burst every 100,000 to 1,000,000 years. Only a small percentage of these would be beamed towards Earth. Estimates of rate of occurrence of short-duration GRBs are even more uncertain because of the unknown degree of collimation, but are probably comparable.&lt;/p&gt;&#xA;  &lt;/blockquote&gt;&#xA;  &#xA;  &lt;p&gt;'A small percentage' isn't too specific. &lt;a href=&quot;http://www.bbc.com/news/science-environment-21082617&quot; rel=&quot;nofollow noreferrer&quot;&gt;The BBC article&lt;/a&gt; that is cited in this passage says the following:&lt;/p&gt;&#xA;  &#xA;  &lt;blockquote&gt;&#xA;    &lt;p&gt;Observations of deep space suggest that gamma ray-bursts are rare. They are thought to happen at the most every 10,000 years per galaxy, and at the least every million years per galaxy.&lt;/p&gt;&#xA;  &lt;/blockquote&gt;&#xA;  &#xA;  &lt;p&gt;However, the 'small percentage' is never elaborated on.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;$^1$&lt;strong&gt;An estimate&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth will become uninhabitable long before the Sun swallows it up - if it is swallowed up - because its surface temperature will be so high life cannot exist. I wanted to see if I could figure out when that would be.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can approximate the temperature of a planet by using the formula for &lt;a href=&quot;https://en.wikipedia.org/wiki/Effective_temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;effective temperature&lt;/a&gt;:&#xA;$$T=\left(\frac{L(1-a)}{16 \pi \sigma D^2} \right)^{\frac{1}{4}}$$&#xA;where $L$ is the star's luminosity, $a$ is the planet's albedo $\sigma$ is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_constant&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stefan-Boltzmann constant&lt;/a&gt;, and $D$ is the distance from the planet to the star.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The current mean temperature of Earth is &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth#Atmosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;about 15 degrees Celsius&lt;/a&gt; (288 K). However, this is the average &lt;em&gt;surface temperature&lt;/em&gt;. Fortunately, the equation given for surface temperature is also of the form&#xA;$$T=C L^{\frac{1}{4}}$$&#xA;where $C$ is a constant. This means that&#xA;$$T^4 \propto L$$&#xA;The boiling point of water is 373 K, which is 1.295 times the current surface temperature. If we plug this in,&#xA;$$L= \propto (1.295)^{\frac{1}{4}} \approx. 2.81$$&#xA;So the luminosity of the Sun would have to be about 2.81 times the current luminosity of the Sun. This value isn't on the graph I gave at the top, though it appears to be about 7 billion years from now. &lt;a href=&quot;https://en.wikipedia.org/wiki/Timeline_of_the_far_future&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; gives this point as only 1 billion years from now, because of a greenhouse effect. So we've only got 1 billion years to live!&lt;/p&gt;&#xA;" OwnerUserId="1399" LastEditorUserId="-1" LastEditDate="2017-04-13T12:59:06.653" LastActivityDate="2015-02-24T03:41:37.933" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="4275" PostTypeId="2" ParentId="4273" CreationDate="2015-01-15T22:18:07.143" Score="10" Body="&lt;p&gt;The end of multicellular life (and of life itself) has been the subject of many documentaries, many of which are based on scientific observations and associated assumptions of the past in the rocks and out in space. Some are outright bizarre imaginings of people. But, one important aspect is that we need to look to the past evidence on Earth to gauge the likelihood of an event occurring in the future - though, given the fact that we are still exploring the mechanisms behind these past events, it is hard to say which may happen next.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first place to look are the mechanisms of past mass-extinctions on Earth. A few examples are below:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;An asteroid/comet impact - which is a widely accepted theory of the cause of the &lt;a href=&quot;http://www2.jpl.nasa.gov/sl9/back3.html&quot;&gt;Cretaceous-Neogene extinction event&lt;/a&gt; that wiped out a significant proportion of life 65 million years ago, including most of the dinosaurs.  This potentially could occur at anytime with little or no warning.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Mass volcanism - such as the formation of the Siberian Traps, what is thought by many scientists to have caused the extensive &lt;a href=&quot;http://science.nasa.gov/science-news/science-at-nasa/2002/28jan_extinction/&quot;&gt;extinction event (over 90% life forms extinct) at the end of the Permian period&lt;/a&gt; around 250 million years ago.  The onset of these may be detected.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Gamma ray burst - which some scientists hypothesise, through computer modelling, may caused a &lt;a href=&quot;http://news.nationalgeographic.com.au/news/2009/04/090403-gamma-ray-extinction.html&quot;&gt;mass extinction at the end of the Ordovician period&lt;/a&gt;, around 440 million years ago.  This is very conjectural, but may occur without warning.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S1342937X13001597&quot;&gt;Nebula Winters&lt;/a&gt;, a relatively recent theory presented in the journal &lt;em&gt;Gondwana Research&lt;/em&gt;, in that encounters with astronomical nebulae can be (and according to theory in the article, has been) be catastrophic for life on the planet. Including their theory that a starburst may have caused the Snowball Earth global glaciation events.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Some of these events can be sudden, without warning, whereas some can occur concurrently and their effects take some time - for example, the extinction event at the end of the Permian is theorised to have had multiple causes - volcanism, impact, methane clathrate release etc and the extinction occurred in pulses separated by thousands of years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some suggest that we are in a mass extinction now, as presented in the article &lt;a href=&quot;http://www.livescience.com/47733-humans-destroy-earth-biodiversity.html&quot;&gt;6th Mass Extinction? Humans Kill Species Faster Than They're Created&lt;/a&gt;, where human influences and manipulation may be replicating some aspects of past mass extinctions.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-01-15T22:42:19.677" LastActivityDate="2015-01-15T22:42:19.677" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4276" PostTypeId="1" AcceptedAnswerId="4278" CreationDate="2015-01-16T06:05:07.153" Score="12" ViewCount="436" Body="&lt;p&gt;The Anthropocene is described by &lt;a href=&quot;http://en.wikipedia.org/wiki/Anthropocene&quot;&gt;Wikipedia&lt;/a&gt; as&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;an informal geologic chronological term for the proposed epoch that began when human activities had a significant global impact on the Earth's ecosystems&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Due to its informal nature and not wide acceptance, there is often debate among adherents about when the Anthropocene is supposed to have started. &lt;em&gt;Note: this is not a question about this debate.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A working group recently suggested in the article &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S1040618214009136&quot;&gt;When did the Anthropocene begin? A mid-twentieth century boundary level is stratigraphically optimal&lt;/a&gt; (Zalasiewicz et al. 2015) has taken a different approach, looking at the effects of human activity on the chemostratigraphic record, suggesting that the Anthropocene epoch ought to have its beginning at the start of the nuclear age.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the article's abstract:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We propose an appropriate boundary level here to be the time of the world's first nuclear bomb explosion, on July 16th 1945 at Alamogordo, New Mexico; additional bombs were detonated at the average rate of one every 9.6 days until 1988 with attendant worldwide fallout easily identifiable in the chemostratigraphic record. Hence, Anthropocene deposits would be those that may include the globally distributed primary artificial radionuclide signal, while also being recognized using a wide range of other stratigraphic criteria. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This question is &lt;em&gt;not&lt;/em&gt; about the legitimacy of such an epoch, but looks at the main point of the working group's findings that radionuclides from nuclear testing may have a measurable imprint on the chemostratigraphic record.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Have there been any global correlation of artificial radionuclides in the recent chemstratigraphic record to justify this as a possible Holocene-Anthropocene boundary?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-01-16T06:11:29.277" LastActivityDate="2015-01-16T20:21:42.200" Title="Nuclear testing and the Anthropocene, a chemostratigraphic link?" Tags="|geochemistry|human-influence|stratigraphy|geochronology|anthropocene|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4277" PostTypeId="2" ParentId="4276" CreationDate="2015-01-16T08:36:42.560" Score="5" Body="&lt;p&gt;The chapter on the Anthropocene (&lt;strong&gt;Zalasiewicz et al., 2012&lt;/strong&gt;) of &quot;The Geological Timescale 2012&quot; quote 3 papers that used artificial radionucleotides as stratigraphic markers: &lt;strong&gt;&lt;a href=&quot;http://link.springer.com/chapter/10.1007%2F1-4020-2146-1_6&quot; rel=&quot;nofollow&quot;&gt;Schwikowski (2004)&lt;/a&gt;, &lt;a href=&quot;http://link.springer.com/article/10.1672%2F0277-5212%282004%29024%5B0324%3ADRPD%5D2.0.CO%3B2&quot; rel=&quot;nofollow&quot;&gt;Turetsky et al. (2004)&lt;/a&gt;&lt;/strong&gt; and &lt;strong&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0033589407000890&quot; rel=&quot;nofollow&quot;&gt;Marshall et al. (2007)&lt;/a&gt;&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first one (&lt;strong&gt;&lt;a href=&quot;http://link.springer.com/chapter/10.1007%2F1-4020-2146-1_6&quot; rel=&quot;nofollow&quot;&gt;Schwikowski, 2004&lt;/a&gt;&lt;/strong&gt;) used them in the context of dating ice cores from Alpine glaciers and the second one (&lt;strong&gt;&lt;a href=&quot;http://link.springer.com/article/10.1672%2F0277-5212%282004%29024%5B0324%3ADRPD%5D2.0.CO%3B2&quot; rel=&quot;nofollow&quot;&gt;Turetsky et al.,2004&lt;/a&gt;&lt;/strong&gt;)  dated peat deposits using various methods including &quot;fallout isotopes from the Chernobyl accident and nuclear weapons testing&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately I do not have access to these 2 papers and therefore can't really go in the details.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The last one (&lt;strong&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0033589407000890&quot; rel=&quot;nofollow&quot;&gt;Marshall et al., 2007&lt;/a&gt;&lt;/strong&gt;) used them to date salt marsh from England. They used specifically &lt;sup&gt;137&lt;/sup&gt;Cs and &lt;sup&gt;241&lt;/sup&gt;Am (both, according to them, can be however affected by industrial discharge from nuclear powerplant), but also more interestingly a &lt;sup&gt;14&lt;/sup&gt;C &quot;bomb spike&quot;, following &lt;strong&gt;&lt;a href=&quot;https://journals.uair.arizona.edu/index.php/radiocarbon/article/download/3882/3307&amp;amp;ei=5cq4VJAjya1pjsqAqAw&amp;amp;usg=AFQjCNGi1zrrvUE6_r8KR2M8i6mijpFLrw&amp;amp;sig2=-xxIoTkCkJta3k1j8_RkXw&quot; rel=&quot;nofollow&quot;&gt;Goodsite et al. (2001)&lt;/a&gt;&lt;/strong&gt;. Indeed &lt;sup&gt;14&lt;/sup&gt;C records shows a substantial increase from 1950 to 1963 (USA and USSR both stopped atmospheric nuclear weapons testing in december 1962), followed by a steady decline toward nowadays values.&#xA;&lt;strong&gt;&lt;a href=&quot;https://journals.uair.arizona.edu/index.php/radiocarbon/article/download/3882/3307&amp;amp;ei=5cq4VJAjya1pjsqAqAw&amp;amp;usg=AFQjCNGi1zrrvUE6_r8KR2M8i6mijpFLrw&amp;amp;sig2=-xxIoTkCkJta3k1j8_RkXw&quot; rel=&quot;nofollow&quot;&gt;Goodsite et al. (2001)&lt;/a&gt;&lt;/strong&gt; reports that the &lt;sup&gt;14&lt;/sup&gt;C can be used for dating at least in all the Northern hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;14&lt;/sup&gt;C bomb pulse dating seems to be since then a rather popular method in forensics as well judging by a quick google search.&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2015-01-16T13:39:53.663" LastActivityDate="2015-01-16T13:39:53.663" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4278" PostTypeId="2" ParentId="4276" CreationDate="2015-01-16T10:39:41.190" Score="6" Body="&lt;p&gt;Certain anthropogenic radionuclides have pragmatic advantages as markers for the start of the anthropocene.  The advantage of radionuclides over anthropogenic stable nuclides is that the primordial production of all but a few radionuclides has decayed away.  Thus natural background levels are below detection by sensitive analytical methods except in a few localized situations (e.g. preCambrian natural reactors). Even radionuclides that occur naturally may be useful if the anthropogenic signal is much greater than the natural levels. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;An important trait for a radionuclide stratigraphic marker is that it has a long enough half-life so the anthropogenic material remains in the sediments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other important trait for a stratigraphic marker is that it is not redistributed significantly in the environment and stays with the sediments of the proper age. For this reason, &lt;sup&gt;137&lt;/sup&gt;Cs and plutonium isotopes are valuable since they have low solubility/strong adsorption onto sediments and were distributed widely by atmospheric nuclear testing. However, this does not mean that the radionuclides won't be redistributed. The radionuclides can be redistributed by water, wind, or mass wasting. Colloidal transport can move particles even in saturated groundwater and the vadose zone. In fact, &lt;a href=&quot;http://lonestar.sierraclub.org/air/Sierra%20Club%20ASARCO%20Study.pdf&quot; rel=&quot;nofollow&quot;&gt;levels of atmospheric fallout plutonium have been used to interpret the redistribution of other contaminants.&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even with very low solubility there can be some dissolved transport into earlier or later sediments. For example, &lt;a href=&quot;http://cafethorium.whoi.edu/website/projects/groundwater.html&quot; rel=&quot;nofollow&quot;&gt;Woods Hole Oceanographic Institute&lt;/a&gt; has determined that plutonium mobility may be affected by oxidation state and that more mobile &lt;sup&gt;244&lt;/sup&gt;Cm can be transported before it decays to &lt;sup&gt;240&lt;/sup&gt;Pu. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, anthropogenic radionuclides, particularly those of long half life and low solubility that were produced during atmospheric testing, have properties that make for pretty good stratigraphic markers. But the limitations should be kept in mind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An additional problem is in defining the 'start' of the anthropocene as fitting your marker rather than the other way around.  Certainly, people have had had geologic and ecological impacts before 1945. There are indications that &lt;a href=&quot;http://www.biogeosciences.net/11/4099/2014/bg-11-4099-2014.html&quot; rel=&quot;nofollow&quot;&gt;aboriginal burning regimes over 20,000 years caused nutrient export with effects that can be seen in current groundwater chemistry&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastEditorUserId="87" LastEditDate="2015-01-16T13:37:47.557" LastActivityDate="2015-01-16T13:37:47.557" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4279" PostTypeId="2" ParentId="4273" CreationDate="2015-01-16T17:21:57.883" Score="6" Body="&lt;p&gt;According to a recent Scientific American article, in about a half-billion years the Sun will have expanded enough and the Earth's orbit decayed enough that Earth will no longer be in the &quot;habitable zone&quot;.  (Earth is already on the inner margin of that zone.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Of course, humans will destroy things far sooner than that.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;BTW:&lt;/strong&gt; For folks interested in this it's worth it to look up that article: &lt;a href=&quot;http://www.scientificamerican.com/article/planets-more-habitable-than-earth-may-be-common-in-our-galaxy/&quot; rel=&quot;nofollow&quot;&gt;Planets More Habitable Than Earth May Be Common in Our Galaxy&lt;/a&gt; -- published in the last month or two.  I just skimmed it -- didn't read in any detail, but it discussed the criteria of a habitable planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also relevant: &lt;a href=&quot;http://www.scientificamerican.com/article/earths-days-are-numbered/&quot; rel=&quot;nofollow&quot;&gt;Earth's Days Are Numbered&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2453" LastEditorDisplayName="user889" LastEditDate="2015-01-16T21:32:22.140" LastActivityDate="2015-01-16T21:32:22.140" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4280" PostTypeId="2" ParentId="1048" CreationDate="2015-01-16T17:42:37.763" Score="4" Body="&lt;ol&gt;&#xA;&lt;li&gt;A rock is a large stone - immovable by hand possibly&lt;/li&gt;&#xA;&lt;li&gt;Rock is made up of stone in the sense where stone is a substance&lt;/li&gt;&#xA;&lt;li&gt;Stones are fragments of a rock also made up of stone but are themselves objects&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The problem here is differentiating between a stone and stone. One being an object and the other a substance? Once clarified then the difference between a rock and a stone can be possibly be clarified.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to answer the question above - yes there is a difference - a rock is an object and stone is a substance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the question was 'is there a difference between a rock and a stone' then size or weight could possibly be the answer.&lt;/p&gt;&#xA;" OwnerUserId="2454" LastEditorUserId="20" LastEditDate="2015-02-01T20:39:31.207" LastActivityDate="2015-02-01T20:39:31.207" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4281" PostTypeId="2" ParentId="4273" CreationDate="2015-01-16T18:47:08.320" Score="8" Body="&lt;p&gt;You've missed a number of calamities:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Everything dies because all plant life dies from ever decreasing levels of CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere.&lt;br&gt;&#xA;This is projected to happen within less than a billion years.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Everything dies because the oceans boil away and the Earth becomes Venus 2.0.&lt;br&gt;&#xA;This is projected to happen within one or two billion years due to increased luminosity from our Sun.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Everything dies because plate tectonics stops.&lt;br&gt;&#xA;This is projected to happen shortly after the oceans boil away.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;These inevitable events will all happen well before our Sun becomes a red giant (which is another inevitable event). All of the other calamities presented in the opening post are only possibilities. Unless something intervenes to move the Earth away from the Sun and add CO&lt;sub&gt;2&lt;/sub&gt; to the atmosphere, the end of life as we know it is an inevitability that will happen long before the Sun turns into a red giant. That something that staves off the end of life as we know it a billion or so years from now  will be the doing of our children's children's ... children, if humanity ever lives that long.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-01-16T18:47:08.320" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4282" PostTypeId="1" AcceptedAnswerId="4284" CreationDate="2015-01-16T20:01:13.017" Score="13" ViewCount="617" Body="&lt;p&gt;Every time I read a news article about Antarctic ice extent, I don't seem to have a clear answer as to what the deal is. If I look at the February sea ice extent from the National Snow and Ice Data Center (NSIDC), I get no trend that I can see:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/YKzXj.gif&quot; alt=&quot;February extent&quot;&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I look at the September data from NSIDC, then I get a clear increase.&lt;img src=&quot;https://i.stack.imgur.com/My43z.png&quot; alt=&quot;September extent&quot;&gt;. NSIDC even tells you what the trend is. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;﻿Monthly Antarctic September ice extent for 1979 to 2014 shows an increase of 1.3% per decade relative to the 1981 to 2010 average.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Finally, if I look at the monthly values it is even trickier: &lt;img src=&quot;https://i.stack.imgur.com/HYDuc.png&quot; alt=&quot;monthly extent&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I can tell is that the minimum extent seems to be unchanged, while there is an increase in the maximum extent. If I where to analyze the trend using all the data, I wonder if any significant trend would be extracted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't want to create any controversies, as I realize that the gains in the Antarctic (small increase of ~100,000 km2 per decade) are much smaller than the loss in the Arctic (decrease of ~500,000 km2 per decade) (&lt;a href=&quot;http://nsidc.org/cryosphere/seaice/characteristics/difference.html&quot; rel=&quot;noreferrer&quot;&gt;NSIDC&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My questions are: Considering the level of variability in coverage, can the Antarctic sea ice extent be considered at &quot;record levels&quot;? If so, what is the consensus on the causes of  this increase?&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-04-25T10:46:41.903" Title="Is Antarctic sea ice at record levels?" Tags="|glaciology|antarctic|sea-ice|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4283" PostTypeId="2" ParentId="4276" CreationDate="2015-01-16T20:21:42.200" Score="6" Body="&lt;p&gt;I will try to plainly answer your question about an artificial radionuclide production/diffusion resulting from human activities, without getting into the discussion of deciding if this is geochronologically relevant or not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would point Figure 1 of this &lt;a href=&quot;http://www.irsn.fr/EN/Research/publications-documentation/radionuclides-sheets/environment/Pages/Tritium-environment.aspx&quot;&gt;paper&lt;/a&gt; which indicate the average tritium (&lt;sup&gt;3&lt;/sup&gt;H) levels in the northern hemisphere between 1945 and 2008. Before 1945 background levels were low and are now again nearly where they were before the 40's, as Tritium half life is ~12.5 y only. Each peak were connected with a nuclear bomb detonation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This other paper &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://sp.lyellcollection.org/content/395/1/255.full.pdf+html&quot;&gt;Wolff, E. W. (2014). &quot;Ice Sheets and the Anthropocene.&quot; Geological Society, London, Special Publications 395(1): 255-263.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;have a explicit figure on the matter as well (Figure 1) showing a similar peak during the 1900's for measurement of beta radioactivity measurements in ice cores. Human made nuclear device explosions are a clear marker in this case. I assume this is only one case among many,  as other posters in this thread pointed out.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2015-01-16T20:21:42.200" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4284" PostTypeId="2" ParentId="4282" CreationDate="2015-01-17T00:58:03.507" Score="11" Body="&lt;p&gt;There have been a number of studies based on observations and modelling of the Antarctic Sea Ice trends.  One major observation is that since continuous satellite coverage began in late 1978 (&lt;a href=&quot;http://www.cgd.ucar.edu/staff/cdeser/docs/fan.antarctic_seaice_trends.grl14.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;), there has been an increase in annual Antarctic sea ice extent (1)(2)(3)(4), that reach ~28% of the Arctic sea ice loss (1).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Critically, according to Simmonds (2015) (1) (and Fan et al. 2014 (3)), that despite interannual, sub-decadal and multidecadal variations, there is a statistically significant increasing trend in sea ice extent for all seasons since late 1978 (As shown in the image below).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/VuMcF.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Caption (from the &lt;a href=&quot;https://nsidc.org/cryosphere/sotc/sea_ice.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NSIDC&lt;/a&gt;): &lt;em&gt;Arctic and Antarctic Sea Ice Extent Anomalies, 1979-2012: Arctic sea ice extent underwent a strong decline from 1979 to 2012, but Antarctic sea ice underwent a slight increase, although some regions of the Antarctic experienced strong declining trends in sea ice extent. Thick lines indicate 12-month running means, and thin lines indicate monthly anomalies.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Essentially, the sea ice extent annual trend is at record-levels &lt;strong&gt;&lt;em&gt;since records began&lt;/em&gt;&lt;/strong&gt; with continuous satellite coverage (from late 1978).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to why this trend is occurring, there is a considerable amount of uncertainty (1)(2)(3)(4), particularly in reconciling modeled sea ice with the extent observed (1).  Simmonds (2015) (1) suggest that this could just be a consequence of the different dynamics between the Arctic and Antarctic - i.e. one model does not fit both ice caps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Observations documented by Fan et al (2014)(3) indicate that since 1979, there has been a decrease in sea surface temperatures (SST) and surface air temperatures around Antarctica, with the exception of the Antarctic Peninsula and surrounding seas. The trends indicate that in the southern summer (December-February) there is a trend of SST dropping by 0.6°C corresponding to a 9% increasing trend in sea ice extent during the same time - this is also noted by Simmonds (2015) (1) as being the greatest trend in sea ice extent.  This is accompanied by intensified westerly winds and a strengthened meridional sea level pressure gradient, both in the southern summer and in the annual mean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fan et al. (2014) (3) suggest that there is evidence for a multidecadal climate variability regime occurring in the region - this stands to reason considering that the time of observations of sea ice extent has only been ~35 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There have been several theories suggested in the literature, below are a few of them:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Fan et al. (2014) (3) describe an earlier idea that the increase in greenhouse gases and ozone depletion may cause an increase in the increased westerly winds, there is considerable uncertainty in the interaction between these factors (4).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Models from Holland et al. (2014) (4) suggest a link between Antarctic-wide ice thickness and area trends contributing to overall sea ice trends.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Related to the models above, several papers suggest that the mechanism is related to increases in meltwater fluxes from the Antarctic continent itself (2)(3).  The meltwater flux is modelled to have increased during the southern summer, depositing greater amounts of cool freshwater into the surface layers of the surrounding Southern Ocean, resulting in cooler SSTs in the southern summer, potentially causing the increase in summer sea ice extent trend.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;However, &lt;strong&gt;most critically&lt;/strong&gt;, Holland et al. (2014) (4) note that the freshwater 'extraction' by sea ice is a small percentage of the actual fresh meltwater flux. Instead they model that instead of freshwater flux, the driver is based on trends of Antarctic ice thickness and area. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;This means that the increase in sea ice is not a 'counter balance' for the ice melted from the continental ice sheets, but rather, according to the models, the increasing sea ice extent appears to be a symptom of the continental ice sheet melting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1) Simmonds 2015 &lt;a href=&quot;http://www.igsoc.org:8080/annals/56/69/a69A909.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Comparing and contrasting the behaviour of Arctic and Antarctic&#xA;sea ice over the 35 year period 1979–2013&lt;/a&gt; &lt;em&gt;Annals of Glaciology&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) Bitanja et al. 2015 &lt;a href=&quot;http://www.igsoc.org/annals/56/69/a69a001.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;The effect of increased fresh water from Antarctic ice shelves on&#xA;future trends in Antarctic sea ice&lt;/a&gt; &lt;em&gt;Annals of Glaciology&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(3) Fan et al. 2014 &lt;a href=&quot;http://www.cgd.ucar.edu/staff/cdeser/docs/fan.antarctic_seaice_trends.grl14.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Recent Antarctic sea ice trends in the context&#xA;of Southern Ocean surface climate&#xA;variations since 1950&lt;/a&gt; &lt;em&gt;Geophysical Research Letters&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(4) Holland et al. 2014 &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-13-00301.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Modeled Trends in Antarctic Sea Ice Thickness&lt;/a&gt;, &lt;em&gt;Journal of Climate&lt;/em&gt; (&lt;a href=&quot;http://epic.awi.de/35571/1/holland-etal_reresubmitted.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Full text here&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-01-17T05:30:34.023" LastActivityDate="2015-01-17T05:30:34.023" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4286" PostTypeId="2" ParentId="2355" CreationDate="2015-01-17T13:48:08.530" Score="19" Body="&lt;p&gt;Permafrost is defined as&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;a ground, or medium, (including rocks, soils and organic matter) with a mean annual temperature less than 0 °C for at least 2 consecutive years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The smooth appearance of the walls can be explained by understanding how permafrost works. Permafrost is characterized by an active layer, which is a layer normally at the surface which freeze yearly during winter and thaw during summer - this layer at Yamal can be 1-2 m deep depending on the local ground characteristics (snow depth, albedo, slope, air temperature, thermal conductivity, runoff etc).  The ground in the area is ice-rich.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then let's assume this crater was caused by a methane bubble escaping/exploding and walls could be rough immediately following the event. By deduction, there should not be an active layer found on the walls following the explosion, as it is the first time this ground (walls) were exposed to air. During the middle of the summer, above 0°C air enters the hole due to convection. The ground is ice-rich (can be porous or invisible ice but still ice-rich) and active-layer start to form on the wall. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Due to the near vertical orientation of the walls, saturated soil (or active layer in formation) cannot stand because as soon as it thaw to a depth exceeding its equilibrium limit, it fall at the bottom of the crater due to gravitational forces, exposing a new frozen surface (and the cycle continue until equilibrium can take a few years). Thawing sediments in ice-rich soils can reach saturation quickly, further adding to the weight and accelerating the time of the fall. Rugged and unequal surface are typically the first elements to thaw and fall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I took this picture about an hundred km from the featured crater.&#xA;&lt;img src=&quot;https://i.stack.imgur.com/XZovW.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This display a very ice-rich section of the Yamal Peninsula littoral in the course of erosion. This coastal section has been eroding for decades at least. At the top the active layer is light brown, and look dry (1 m deep). Just under this top-layer, the ice is poly-genetic: ice wedge ice-rich soil and massive ice can be seen as well. The active layer cannot stand on the side for the reasons I exposed in the previous paragraph (gravity).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Side-note, the jagged edges were not initiated by anything related to a pingo. It takes decades, up to many centuries for a pingo to develop until its natural collapse. When it happen, a depression can form at its center - which could lead to a lake, but these are not overnight processes. Also, contours of the pingo mound would not appear as jagged edges if this was a pingo - the remains would appear pretty old and vegetated, alike the surrounding countryside.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastEditorUserId="1411" LastEditorDisplayName="user889" LastEditDate="2016-12-26T14:18:27.867" LastActivityDate="2016-12-26T14:18:27.867" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4287" PostTypeId="1" CreationDate="2015-01-18T00:06:16.023" Score="11" ViewCount="243" Body="&lt;p&gt;Current fusion reactor schemes require deuterium and the plan is to extract it from the ocean where it can be found in small abundance. Does deuterium serve some purpose in the oceans? What would happen if there was none left?&lt;/p&gt;&#xA;" OwnerUserId="2463" LastActivityDate="2022-12-27T18:39:42.137" Title="Deuterium-less oceans" Tags="|ocean|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4289" PostTypeId="1" AcceptedAnswerId="4352" CreationDate="2015-01-18T11:52:50.307" Score="10" ViewCount="5263" Body="&lt;p&gt;The notion of a taller-than-skyscraper, so called &quot;&lt;a href=&quot;http://www.sms-tsunami-warning.com/pages/mega-tsunami-wave-of-destruction#.VLucGyuUcVY&quot; rel=&quot;nofollow noreferrer&quot;&gt;megatsunami&lt;/a&gt;&quot; is not new - with the often-reported 524m (1720 feet) high &lt;a href=&quot;http://en.wikipedia.org/wiki/1958_Lituya_Bay_megatsunami&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lituya Bay tsunami of 1958&lt;/a&gt; is sometimes referred as such (despite the wave not reaching that high). In many movies (and some documentaries), there are massive tsunami depicted. Some of these movies depict tsunami taller than skyscrapers (such as in &lt;a href=&quot;https://www.youtube.com/watch?v=fl0USo6q1js&quot; rel=&quot;nofollow noreferrer&quot;&gt;Deep Impact&lt;/a&gt; and &lt;a href=&quot;https://www.youtube.com/watch?v=kJTP_tYkwZY&quot; rel=&quot;nofollow noreferrer&quot;&gt;Haeundae&lt;/a&gt;). There is also evidence of massive tsunami occurring in different places around the world in the past.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We have seen the reality of devastating tsunami in and around the Indian Ocean in 2004 and Japan in 2011 for example.  These, while not being 100's metres high, are still catastrophic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How a tsunami forms and how it travels is well documented (thus is not the subject of this question), nor is this asking about the inland reach of such a disaster, they are answered in the related questions &lt;a href=&quot;https://earthscience.stackexchange.com/q/244/889&quot;&gt;Is a mega tsunami that will destroy America inevitable?&lt;/a&gt;, &lt;a href=&quot;https://earthscience.stackexchange.com/q/2570/889&quot;&gt;Is Atlanta too far inland and too far above sea level to be affected by the comet in “Deep Impact”?&lt;/a&gt; and &lt;a href=&quot;https://earthscience.stackexchange.com/q/64/889&quot;&gt;Why does every tsunami travel differently?&lt;/a&gt;. But rather, the maximum height possible for a tsunami from any cause.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is there a theoretical upper limit for the maximum height of a tsunami?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2018-10-25T22:32:00.707" Title="Mega-tsunami, what is the greatest possible height of a tsunami?" Tags="|tsunami|" AnswerCount="3" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="4291" PostTypeId="2" ParentId="4287" CreationDate="2015-01-18T22:36:52.300" Score="2" Body="&lt;p&gt;Replacing 20% or more of the normal water in ones body with heavy water results is toxic (Kushner 1999). Then again, a number of vitamins are toxic in high doses, but vitamins are essential to human life. Could deuterium in small doses be essential to life? That's exactly what Somlyai et al. argue in their paper (Somlyai 1993).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it's a bit premature to start shouting &quot;peak deuterium.&quot; We don't even know if ITER will prove to be successful, let alone point the way to commercially successful fusion. Even if it does prove to be successful, the deuterium consumption rate will be tiny. By the time our children's children's ... children would have to shout peak deuterium, we'll have gone on to even bigger and better things (if humanity lives that long).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nrcresearchpress.com/doi/abs/10.1139/y99-005#.VLwvmVptIUU&quot; rel=&quot;nofollow&quot;&gt;Kushner, et al. (1999), &quot;Pharmacological uses and perspectives of heavy water and deuterated compounds,&quot; &lt;em&gt;Canadian Journal of Physiology and Pharmacology&lt;/em&gt;, 77.2:79-88.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/001457939381479J&quot; rel=&quot;nofollow&quot;&gt;Somlyai, et al (1993), &quot;Naturally occurring deuterium is essential for the normal growth rate of cells,&quot; &lt;em&gt;FEBS letters&lt;/em&gt;, 317.1:1-4.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-01-18T22:36:52.300" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4292" PostTypeId="2" ParentId="4289" CreationDate="2015-01-19T13:11:32.700" Score="2" Body="&lt;p&gt;The height will be limited by the maximum height of the &lt;a href=&quot;http://en.wikipedia.org/wiki/Rim_%28craters%29&quot; rel=&quot;nofollow&quot;&gt;rim wall&lt;/a&gt;. For a Chicxulub like scenario the rim wall will be at least a km high. The initial impact will off course cause some water to evaporate, some will be ejected many kilometers into the atmosphere (e.g., during the 'splash') but for the sake of this question I am discarding transient deformation during the first few seconds/minutes and assuming that the Tsunami only results from permanent deformation as in after earthquakes.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2015-01-19T13:18:33.607" LastActivityDate="2015-01-19T13:18:33.607" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4293" PostTypeId="1" AcceptedAnswerId="4308" CreationDate="2015-01-20T09:20:28.557" Score="7" ViewCount="121" Body="&lt;p&gt;Recently, there has been explosive deep-ocean volcanism detected along the slowly-spreading Gakkel Ridge in the Arctic Ocean (see map below), according the National Geographic news article &lt;a href=&quot;http://news.nationalgeographic.com.au/news/2008/06/080626-arctic-volcano.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Arctic Volcanoes Found Active at Unprecedented Depths&lt;/a&gt;, specifically, the article reports that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Powerful eruptions sent a plume of carbon dioxide, helium, and liquid lava up into the Arctic waters.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/aC3ao.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Gakkel_Ridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is the geochemical source for the helium detected in deep Arctic explosive eruptions?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-01-22T11:24:05.343" LastActivityDate="2015-02-02T10:15:51.367" Title="What is the geochemical source for the helium detected in deep Arctic explosive eruptions?" Tags="|volcanology|geochemistry|sea-floor-spreading|arctic|ocean-ridge|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4294" PostTypeId="2" ParentId="4242" CreationDate="2015-01-20T12:42:17.720" Score="8" Body="&lt;p&gt;The presence or absence of a large number of massive buildings has no bearing on where and when earthquakes occurs, or their magnitudes; particularly along major fault systems such as the San Andreas Fault.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earthquakes mainly occur on tectonic plate boundaries, such as the San Andreas Fault, near San Francisco, or the fault systems through Turkey, Italy, New Zealand, near Japan and the Rift Valley in Africa. However, this does not preclude earthquakes from occurring elsewhere, such as in the middle of a tectonic plate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For many decades some Australians thought that Australia was immune to earthquakes because it lies in the middle of the Indo-Australian plate; then a number of large earthquakes occurred in the latte half of the 20th Century causing people to have a rethink.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fact is geological faults occur everywhere: some are major, others are minor; some are active, others aren't. If ground movement occurs on a fault an earthquake or tremor will happen regardless of any extra weight on the Earth's surface at any location.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The San Andreas Fault, like many major faults, is not one single fault, but a fault zone of sub parallel faults of varying lengths. The accumulation of stresses along the individual faults are not uniform throughout the entire system. There is no precisely predictable pattern to when an earthquake will occur or where along these major fault systems&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a picture on the following website showing the system of faults in the San Andreas Fault in the San Francisco bay area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/San_Andreas_Fault&quot;&gt;https://en.wikipedia.org/wiki/San_Andreas_Fault&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The size and occurrence of a earthquakes along tectonic plate boundaries is dependent on the speed at which the plates are moving past each other and how much they snag on each other and the strength of the rock at the snag points. With very strong rock at the snag points a lot of pressure can build up over a long time and when that pressure is eventually released when the rock breaks or slips a strong earthquake will occur.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many earthquakes will occur within the San Andreas Fault system, but it doesn't necessarily mean that San Francisco will be affected any time soon or how badly it will be affected.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-01-20T12:42:17.720" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4295" PostTypeId="2" ParentId="3096" CreationDate="2015-01-20T12:59:27.980" Score="5" Body="&lt;p&gt;According to this source the Viking 2 lander had a seismometer and it measured a marsquake&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.vibrationdata.com/earthquakes/Sunquakes.htm&quot; rel=&quot;noreferrer&quot;&gt;http://www.vibrationdata.com/earthquakes/Sunquakes.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Moon has moonquakes. Seismometers where placed on the Moon by the Apollo 12, 14, 15 &amp;amp; 16 mission. Quakes were recorded until 1977 when the seismometers were turned off. &lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-01-20T12:59:27.980" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4296" PostTypeId="2" ParentId="1048" CreationDate="2015-01-20T13:38:10.590" Score="15" Body="&lt;p&gt;Here, you can use this shoddily drawn table.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/HpeOj.jpg&quot; alt=&quot;A table about the difficult to put into words difference between ROCK and STONE&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-01-20T13:38:10.590" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4297" PostTypeId="2" ParentId="2287" CreationDate="2015-01-20T14:34:59.207" Score="4" Body="&lt;p&gt;It seems that tropical forests absorb more carbon dioxide than many scientists have believed before. &lt;a href=&quot;http://www.jpl.nasa.gov/news/news.php?feature=4424&quot; rel=&quot;nofollow&quot;&gt;NASA and NCAR scientists&lt;/a&gt; have shown that tropical forests absorb 1.4 billion metric tons out of a total global absorption of 2.5 billion metric tons. This estimate is much larger than previous estimates and the tropical contribution seems to be much larger than other areas like temperate or boreal forest. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Previously, most climate models showed mid-latitude forests in the Northern Hemisphere absorbing more carbon than tropical forests. Those results were data-limited and suggested that deforestation was causing tropical forests to release more carbon dioxide than they were absorbing. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The new results seem to indicate the opposite and are based in a more comprehensive analysis of available data. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... reconciles results at every scale from the pores of a single leaf, where photosynthesis takes place, to the whole Earth, as air moves carbon dioxide around the globe.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-01-20T14:34:59.207" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4298" PostTypeId="1" CreationDate="2015-01-20T20:21:29.087" Score="4" ViewCount="116" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;This question is now &lt;a href=&quot;https://worldbuilding.stackexchange.com/questions/9013/how-can-i-keep-dense-fog-in-an-area-for-half-a-day&quot;&gt;here&lt;/a&gt; on Worldbuilding Stack Exchange &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I am a writer, and this question is for a fictional work. However, given its nature, I believe it is better suited here than Writers Stack Exchange. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In my fictional world, I have an area that is supposedly covered with fairly thick fog during most of the night and nearly all of the morning (it can leave a bit before noon if necessary). My question is this: &lt;strong&gt;What factors would I need to achieve this effect?&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Factors: &#xA;It is a fantasy world, so the factors need to be natural. The area is within a city, and is very densely inhabited. The area is enclosed by large trees, and large roots run all over the ground. The fog does not need to reach any higher than 7 feet, but it does need to cover nearly the whole area (a generous approximation would be 288 ft by 228 ft - about 65,000 square feet). The walls of the area (giant roots/tree trunks) vary in distance from each other a lot. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let me know if you need more details on the surroundings. &lt;/p&gt;&#xA;" OwnerUserId="2472" LastEditorUserId="-1" LastEditDate="2017-04-13T12:52:35.360" LastActivityDate="2015-01-27T01:22:47.397" Title="Fictional Land - How can I keep dense fog in an area for half a day?" Tags="|clouds|hypothetical|humidity|" AnswerCount="1" CommentCount="11" ClosedDate="2015-01-21T03:26:10.330" ContentLicense="CC BY-SA 3.0" />
  <row Id="4299" PostTypeId="2" ParentId="4298" CreationDate="2015-01-21T00:02:33.843" Score="2" Body="&lt;p&gt;The heat of the Sun can &quot;burn off&quot; fog. So a lack of direct sunshine, cool temperatures &amp;amp; humidity (evaporation of water from a nearby body of water or saturated or wet ground) are key to maintaining fog. The air must be moist!&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-01-21T00:02:33.843" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4300" PostTypeId="1" CreationDate="2015-01-21T04:17:14.693" Score="14" ViewCount="861" Body="&lt;p&gt;I am considering taking a course in linear algebra and wanted to get a survey to see how important it is. My goal is not just to understand how to push the buttons in some software (e.g. GW Vistas, Aquiferwin32), but to really understand how groundwater modeling works. &lt;/p&gt;&#xA;" OwnerUserId="2475" LastEditorUserId="192" LastEditDate="2015-01-22T06:44:11.937" LastActivityDate="2015-01-22T06:44:11.937" Title="How important is understanding linear algebra in groundwater modeling?" Tags="|hydrology|models|numerical-modelling|groundwater|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4301" PostTypeId="1" AcceptedAnswerId="4303" CreationDate="2015-01-21T20:39:16.963" Score="7" ViewCount="418" Body="&lt;p&gt;I read that the &lt;em&gt;acidic&lt;/em&gt; character, or, better, &lt;em&gt;persilicic&lt;/em&gt; character of a rock is determined by a content of more than $65\%\ \ce{SiO_2}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A rock is defined, by the texts available to me, as &lt;em&gt;mesosilicic&lt;/em&gt; (or &lt;em&gt;intermediate&lt;/em&gt;) when its $\ce{SiO_2}$ content is contained in the interval $52\%-65\%$, while it is called &lt;em&gt;hyposilicic&lt;/em&gt; (or &lt;em&gt;basic&lt;/em&gt;) when $\ce{SiO_2}&amp;lt;52\%$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I correctly understand the $\ce{SiO_2}$ contained in the rock as a part of a mineral other than pure $\ce{SiO_2}$, for example, the $\ce{Si_2O_4}$ part of anorthite $\ce{CaAl_2Si_2O_8}$, is calculated into the quantity of total silica. What I cannot understand at all, is whether mass or volume is taken into account.&lt;/p&gt;&#xA;" OwnerUserId="620" LastEditorUserId="725" LastEditDate="2016-09-10T09:12:51.477" LastActivityDate="2016-09-10T09:12:51.477" Title="Acidity of rock" Tags="|geochemistry|mineralogy|petrology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4302" PostTypeId="2" ParentId="4300" CreationDate="2015-01-21T21:25:24.107" Score="-4" Body="&lt;p&gt;These days, not so much.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even people who write their own sophisticated mesh based groundwater modeling codes usually make extensive use of sparse/dense numerical libraries/solvers that are written by linear algebra experts (e.g., UMFPACK/MUMPS/PETSc etc.). The author of these libraries really know their stuff.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if you are writing your own groundwater modeling code you simply call the above libraries to solve your equations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Off course 20 years ago when there were no such libraries people had no choice. That is why codes written in 80s and early 90s typically have their own (often poor performing) solver.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: If you're just using a code then don't bother with linear algebra at all. The only thing you need to know is that for large problems you need to use an 'iterative' solver.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2015-01-21T21:40:53.590" LastActivityDate="2015-01-21T21:40:53.590" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4303" PostTypeId="2" ParentId="4301" CreationDate="2015-01-22T04:27:06.510" Score="6" Body="&lt;p&gt;According the website &lt;a href=&quot;http://www.tulane.edu/~sanelson/eens212/igrockclassif.htm&quot;&gt;http://www.tulane.edu/~sanelson/eens212/igrockclassif.htm&lt;/a&gt; from Tulane University silica content in igneous rock is based on mass. Below is copy of the relevant part of the web page where it states &lt;strong&gt;wt %&lt;/strong&gt;, weight percent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;General Chemical Classifications&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\ce{SiO2}$ (Silica) Content&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;&amp;gt; 66 wt. % - Acid&#xA;&#xA;52-66 wt% - Intermediate&#xA;&#xA;45-52 wt% - Basic&#xA;&#xA;&amp;lt; 45 wt % - Ultrabasic&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="2470" LastEditorDisplayName="user889" LastEditDate="2015-01-22T06:13:27.283" LastActivityDate="2015-01-22T06:13:27.283" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4304" PostTypeId="2" ParentId="1048" CreationDate="2015-01-22T05:49:01.693" Score="14" Body="&lt;p&gt;I'm quoting from my old &lt;em&gt;The Penguin Dictionary of Geology&lt;/em&gt; by D. G. A Whitten &amp;amp; &#xA;J. R. V. Brooks, published in 1979.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Rock&lt;/strong&gt; (1) To the geologist any mass of mineral matter, whether consolidated or not, which forms part of the Earth's crust ... (2) The&#xA;  civil engineer regards rock as something hard, consolidated, and/or&#xA;  load bearing, which, where necessary, has to be removed by blasting.&#xA;  This concept also accords with the popular idea of the meaning of the&#xA;  word.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;strong&gt;Stone&lt;/strong&gt; In geology the word 'stone' is admissible only in combinations such as limestone, sandstone, etc., or where it is used&#xA;  as the name for extracted material - building stone, stone road. It&#xA;  should not be used as a synonym for rock or pebble.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="20" LastEditDate="2015-02-01T20:41:48.627" LastActivityDate="2015-02-01T20:41:48.627" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4305" PostTypeId="2" ParentId="4300" CreationDate="2015-01-22T06:43:24.573" Score="18" Body="&lt;p&gt;Relatively important, depending on the basic principles of the modeling you are interested in, and to what extent you want to get yourself involved in it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In many areas of computational geophysics, e.g. atmospheric, oceanic, hydrological modeling etc., there are modelers, modelers, and modelers. First group of modelers get model output from somebody else, do some analysis, make some plots, and write about what they found. Then, there are modelers who design their own experiments, play with tunable parameters, maybe even change a few lines in the code and run the model. Finally, there are &lt;em&gt;modelers&lt;/em&gt; - these spend most of their time on building and improving models, both in terms of numerical methods and software design. They could go for few years without publishing a single paper, but boy did they work hard.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are interested in computational science aspects of modeling, i.e. the inner workings of the model and how to improve it, understanding linear algebra as well as numerical methods will prove to be very valuable. While it is likely that you will never end up having to implement that matrix inversion or sparse matrix multiply yourself, and instead use one of many well documented production libraries, it is important to understand how they do it and why they do it in a particular way. From my own experience, I can say that most of the time it won't matter, but sooner or later there comes a situation where having knowledge about how low-level operations work will save you from pulling your hair out for weeks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And this does not go only for linear algebra - I would extend this advice and urge you to strive at also understanding differential equations, discretization, computer architecture, floating-point arithmetic.&lt;/p&gt;&#xA;" OwnerUserId="192" LastActivityDate="2015-01-22T06:43:24.573" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4306" PostTypeId="1" AcceptedAnswerId="4323" CreationDate="2015-01-22T10:12:35.067" Score="6" ViewCount="362" Body="&lt;p&gt;We have had (and are still experiencing) waves of storms passing through this area of the central Queensland 'Capricornia' coast, Australia.  This area is a subtropical coastal environment, close to sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following picture is one I took from my the balcony outside my lab (facing east):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/o1QQ0.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The storm was moving to the north (left) and that part of the sky was a featureless heavy cloud. The conditions were as follows:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Ambient temperature:&lt;/strong&gt; 30C (86F)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Wind:&lt;/strong&gt; strong, to the north&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Conditions:&lt;/strong&gt; Heavy rain periods, heavy thunder and lightning, about 10 minutes later, the sky cleared, temperature rose and the wind dropped to barely a breeze.  Numerous cloud-to-ground and cloud-to-cloud lightning was noticed from this cloud formation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am leaning towards this being a 'scud cloud', but a local weather-enthusiast claims it was a weakly formed non-rotating wall cloud.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What type of cloud is this?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T07:44:47.243" LastActivityDate="2019-08-28T07:44:47.243" Title="What type of storm cloud is this?" Tags="|meteorology|clouds|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4307" PostTypeId="1" AcceptedAnswerId="4342" CreationDate="2015-01-22T11:23:39.730" Score="5" ViewCount="559" Body="&lt;p&gt;Looking at a map of the underwater features of the Arctic Ocean reveals three roughly parallel ridges, separated by basins (see image below):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/0szlH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Lomonosov_Ridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The three ridges, as labelled are the &lt;a href=&quot;http://en.wikipedia.org/wiki/Alpha_Ridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;Alpha Ridge&lt;/a&gt;, &lt;a href=&quot;http://en.wikipedia.org/wiki/Lomonosov_Ridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lomonosov Ridge&lt;/a&gt; and the &lt;a href=&quot;http://en.wikipedia.org/wiki/Gakkel_Ridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gakkel Ridge&lt;/a&gt;, the latter being the slow moving plate boundary between the Eurasian and North American plates as an extension of the Mid Atlantic Rift, according to the Polar Discovery page &lt;a href=&quot;http://polardiscovery.whoi.edu/expedition2/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Arctic Seafloor Expedition: July 1-Aug. 10, 2007&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is the tectonic explanation for these parallel ridges in the Arctic Ocean?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, are they in anyway linked?&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-01-26T09:02:34.847" LastActivityDate="2015-01-28T13:15:18.127" Title="What is the tectonic explanation for parallel ridges in the Arctic Ocean?" Tags="|geophysics|tectonics|arctic|ocean-ridge|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4308" PostTypeId="2" ParentId="4293" CreationDate="2015-01-22T13:15:15.410" Score="4" Body="&lt;p&gt;Helium is formed through the radioactive decay of uranium 238, uranium 235  and Thorium 232. A helium atom is an alpha particle that has collected electrons. The only way that helium is produced on Earth is by such radioactive decay deep underground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Generally, the helium travels along cracks until it reaches a subterranean cavern where it accumulates. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yellowstone National Park in the US is leaking helium. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quoting from the website &lt;a href=&quot;http://www.yellowstonepark.com/2014/02/helium/&quot; rel=&quot;nofollow&quot;&gt;http://www.yellowstonepark.com/2014/02/helium/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the gas is gurgling up from a store that’s been trapped in the Earth’s core for up to 2 billion years. Scientists believe that the&#xA;  helium began its exodus up from the depths roughly 2 million years&#xA;  ago. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The helium was initially released when a “hotspot” of collected magma&#xA;  fought its way to the Earth’s surface and caused a series of volcanic&#xA;  eruptions, the most recent of which occurred 640,000 years ago.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The helium being release at Gakkel Ridge would be of a similar origin and it appears to be released in a manner similar to what is happening at Yellowstone NP. The article you provided a link for also states that carbon dioxide is being release at Gakkel Ridge, which is not inconsistent with the volcanic activity of the ridge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the website &lt;a href=&quot;http://www.helium-corp.com/facts/heliumfound.html&quot; rel=&quot;nofollow&quot;&gt;http://www.helium-corp.com/facts/heliumfound.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Carbon Dioxide is also found in some helium-bearing formations but the&#xA;  presence of this gas is primarily due to its proximity to ancient&#xA;  volcanic activity.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Other website that may be of interest are:&lt;br&gt;&#xA;&lt;a href=&quot;http://www.pa.msu.edu/sciencet/ask_st/051095.html&quot; rel=&quot;nofollow&quot;&gt;http://www.pa.msu.edu/sciencet/ask_st/051095.html&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.anl.gov/articles/underground-helium-travels-earth-s-surface-aquifers-new-study-says&quot; rel=&quot;nofollow&quot;&gt;http://www.anl.gov/articles/underground-helium-travels-earth-s-surface-aquifers-new-study-says&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorDisplayName="user889" LastEditDate="2015-02-02T10:15:51.367" LastActivityDate="2015-02-02T10:15:51.367" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4309" PostTypeId="1" AcceptedAnswerId="4328" CreationDate="2015-01-22T16:08:48.013" Score="17" ViewCount="29894" Body="&lt;p&gt;I am currently learning at school about the climatic conditions (mainly winds, difference in pressure, Coriolis effect, etc.) that cause and affect the monsoons received by India.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the factors mentioned is the shift of the Inter tropical Convergence Zone (ITCZ) towards the Ganga plain in the summers. I tried reading up on Wikipedia to understand this better (&lt;a href=&quot;http://en.wikipedia.org/wiki/Intertropical_Convergence_Zone#Effects_on_weather&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; especially), but couldn't understand much.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could someone explain, in simple terms,&lt;br&gt;&#xA;(a) What the ITCZ and monsoon trough are? Are they just regions of low pressure?&lt;br&gt;&#xA;(b) What causes this to shift away from the equator?&lt;br&gt;&#xA;(c) Does 'convergence' have anything to do with all of this?  &lt;/p&gt;&#xA;" OwnerUserId="2480" LastEditorUserId="81" LastEditDate="2015-01-25T14:03:47.650" LastActivityDate="2018-09-05T06:32:06.853" Title="Why does the Inter tropical Convergence Zone shift?" Tags="|meteorology|climate|wind|monsoon|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4310" PostTypeId="2" ParentId="41" CreationDate="2015-01-22T21:12:39.663" Score="7" Body="&lt;p&gt;An important role of vegetation in carbon sequestration is related to what happens belowground. Plant roots comprise a signficant portion of vegetative biomass and remain in the soil even when a plant dies or is harvested. Plants also exude organic carbon through their roots into the subsurface, in part serving a symbiotic purpose with microorganisms. The top three meters of soil/sediment has been estimated to contain about 2344 Pg of organic carbon, more than the atmosphere and aboveground vegetation combined (Jobbagy and Jackson, Ecological Applications 10(2): 423-236, 2000). Deeper subsoils, although less rich than surface soils, also contain a significant pool of organic carbon. Most of this carbon is plant-derived, either directly (through leaf litter and root decomposition, root exudates, etc.) or indirectly (through subsurface organisms such as bacteria or fungi that depend on plant-derived carbon). Some of this carbon cycles back into the atmosphere quickly through microbial degradation, but part of it is protected from degradation by various mechanisms or moves to deeper regions such that it becomes sequestered for long time periods. So yes, vegetation can contribute to long-term carbon sequestration, although primarily by mechanisms other than the river transport and ocean deposition you proposed.&lt;/p&gt;&#xA;" OwnerUserId="2483" LastActivityDate="2015-01-22T21:12:39.663" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4312" PostTypeId="1" AcceptedAnswerId="4314" CreationDate="2015-01-23T10:47:17.993" Score="7" ViewCount="2629" Body="&lt;p&gt;The fractions of albite $\ce{NaAlSi_3O_8}$ and anorthite $\ce{CaAl_2Si_2O_8}$, which I call $\ce{Ab}$ and $\ce{An}$ in the following list, present in a plagioclase are often used to define it in the following way:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Anorthite: $\ce{An}=90\%-100\%$, $\ce{Ab}=0\%-10\%$;&lt;/li&gt;&#xA;&lt;li&gt;Bytownite: $\ce{An}=70\%-90\%$, $\ce{Ab}=10\%-30\%$;&lt;/li&gt;&#xA;&lt;li&gt;Labradorite: $\ce{An}=50\%-70\%$, $\ce{Ab}=30\%-50\%$;&lt;/li&gt;&#xA;&lt;li&gt;Andesine: $\ce{An}=30\%-50\%$, $\ce{Ab}=50\%-30\%$;&lt;/li&gt;&#xA;&lt;li&gt;Oligoclase: $\ce{An}=10\%-30\%$, $\ce{Ab}=70\%-90\%$;&lt;/li&gt;&#xA;&lt;li&gt;Albite: $\ce{An}=0\%-10\%$, $\ce{Ab}=90\%-100\%$.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;What I am not sure of is whether these fractions are intended as applying to mass, molarity, volume.&lt;/p&gt;&#xA;" OwnerUserId="620" LastEditorUserId="620" LastEditDate="2015-02-28T16:03:52.210" LastActivityDate="2016-03-16T20:13:13.797" Title="The different types of plagioclase" Tags="|geology|geochemistry|mineralogy|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4314" PostTypeId="2" ParentId="4312" CreationDate="2015-01-23T12:16:35.723" Score="8" Body="&lt;p&gt;According to the pages &lt;a href=&quot;http://www.eos.ubc.ca/courses/eosc321/PlagComposition.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Plagioclase composition&lt;/a&gt; (from the textbook: &lt;a href=&quot;https://books.google.com.au/books?id=W50jnwEACAAJ&amp;amp;dq=%22Introduction%20to%20Mineralogy%22%20nesse,%202000&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ei=JT_CVL2QG8mj8AXGrYLoDg&amp;amp;ved=0CCEQ6AEwAQ&quot; rel=&quot;nofollow noreferrer&quot;&gt;Introduction to Mineralogy&lt;/a&gt; Nesse, 2000), the percentage definitions are due to the mole percent of $\ce{Ca^{2+}}$ (from anorthite) and the presumed subsequent $\ce{Na+}$ (from albite) ions present in the sample.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is done under the assumption that the anorthite% + albite% = 100% in a plagioclase sample.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mole percent are usually represented by percentage proportions of the plagioclase end member anorthite, often in the form of An&lt;sub&gt;x&lt;/sub&gt;, where 'x' is the mole percent of $\ce{Ca^{2+}}$ present in the plagioclase sample.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider the following diagram below - the relevent part for your question is across the base of the triangle:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Dnp2W.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Feldspar&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image source&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, oligoclase is An&lt;sub&gt;10%-30%&lt;/sub&gt; means that it would possess a $\ce{Ca^{2+}}$ mole percent of between 10% to 30%, and a corresponding $\ce{Na+}$ mole percent of between 70% to 90%.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-01-23T12:39:51.763" LastActivityDate="2015-01-23T12:39:51.763" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4315" PostTypeId="1" AcceptedAnswerId="4318" CreationDate="2015-01-23T13:40:56.110" Score="19" ViewCount="2117" Body="&lt;p&gt;I know that at least twice in its history Earth was totally frozen. I also know that the last time it happened there were already life on Earth, and it survived. In deep water, under the ice, which was transparent enough for light to penetrate it and support life. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is, why didn't all the water freeze? AFAIK Earth was frozen for 10 million years, so I think it was enough time. Something must have kept deep water from freezing, what was it? Geothermal warmth? Underwater volcanoes? Both seem to be too weak sources of energy for keeping deep ocean liquid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same about Antarctica. I know there was a lake found deep under thick ice, why didn't it freeze?&lt;/p&gt;&#xA;" OwnerUserId="109" LastEditorUserId="725" LastEditDate="2015-01-23T19:07:38.520" LastActivityDate="2015-02-26T06:49:24.000" Title="Why deep ocean didn't freeze during snowball Earth?" Tags="|ocean|earth-history|paleoclimatology|sea-ice|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4316" PostTypeId="2" ParentId="4312" CreationDate="2015-01-23T15:31:30.473" Score="6" Body="&lt;p&gt;I'd like to add to @SabreTooth correct answer and add the following:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Plagioclase in nature commonly has a K-feldspar component: &lt;span class=&quot;math-container&quot;&gt;$\ce{KAlSi3O8}$&lt;/span&gt;. So a plagioclase crystal may be 48% anorthite, 48% albite and 4% K-feldspar. This component is usually written as the &lt;span class=&quot;math-container&quot;&gt;$\ce{Or}$&lt;/span&gt; component (after the mineral orthoclase). This introduces a new problem. Let's say you have a plagioclase with the Composition &lt;span class=&quot;math-container&quot;&gt;$\ce{An49Ab46Or5}$&lt;/span&gt;. Normally you would think that the mineral is an andesine because it has 49% &lt;span class=&quot;math-container&quot;&gt;$\ce{An}$&lt;/span&gt;. However, if you want to project the mineral to the plagioclase side of the ternary feldspar diagram, you need to normalise it to &lt;span class=&quot;math-container&quot;&gt;$\ce{An52Ab48}$&lt;/span&gt;. Now it is a labradorite! So which one is it?&lt;/p&gt;&#xA;&lt;p&gt;Well, there are no defined rules for determining it. However, it doesn't really matter. Remember that these names are artificially divided by us humans. Nature is not so nicely divided but rather quite continuous. Another reason is doesn't really matter is...&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Plagioclase in igneous rocks (which is where you are most likely to find it) is rarely homogenous. It is commonly &lt;strong&gt;zoned&lt;/strong&gt;, meaning that its composition varies across the crystal. Here are maps of &lt;span class=&quot;math-container&quot;&gt;$\ce{Ca^2+}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\ce{Na+}$&lt;/span&gt; distributions inside plagioclase crystals:&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/A7C03.jpg&quot; alt=&quot;Plagioclase X-ray maps&quot; /&gt;&#xA;&lt;sup&gt;source: &lt;a href=&quot;http://serc.carleton.edu/details/images/8598.html&quot; rel=&quot;noreferrer&quot;&gt;http://serc.carleton.edu/details/images/8598.html&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;Brigher colours correspond to higher calcium contents. Each crystal has different composition in different zones! It may be labradorite in the cores whereas the rims would be andesine or oligoclase. Sometimes you may encounter a single crystal exhibiting the entire range from bytownite to oligoclase, which are the compositions that currently occur in igneous rocks. So the exact composition of the plagioclase is meaningless.&lt;/p&gt;&#xA;&lt;p&gt;What about albite and anorthite? These two extreme cases deserve a special treatment.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Albite is technically not even a plagioclase, but rather an alkali feldspar. It occurs in settings which are not your usual igneous rock: low grade metamorphic rocks, metasomatic rocks, pegmatites, etc. In this case the identity of the crystal is indeed interesting, and it is rarely called &amp;quot;plagioclase&amp;quot;, but rather &amp;quot;albite&amp;quot;.&lt;/li&gt;&#xA;&lt;li&gt;Anorthite is extremely rare on Earth. Even the so called &amp;quot;anorthosites&amp;quot; (rocks composed almost entirely of plagioclase) contain labradorite and not true anorthite. Conversely, anorthite (as &lt;span class=&quot;math-container&quot;&gt;$\ce{An_{95-98}}$&lt;/span&gt;) is the main constituent of Lunar anorthosites. These unique rocks and minerals truly deserve to be called anorthites.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-01-23T15:31:30.473" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4317" PostTypeId="1" AcceptedAnswerId="4339" CreationDate="2015-01-23T16:02:29.573" Score="9" ViewCount="4569" Body="&lt;p&gt;As far as I know scientists use oxygen isotope 16 to 18 ratio in air trapped in glaciers (or in old foraminiftera shells) as proxy for temperature in the past. I know that $\ce{^18O}$ is heavier, and it precipitates faster, and $\ce{^16O}$ is lighter, and it evaporates faster.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand that when it's warmer, there is more evaporation and more heavy isotope left in water. Vapor moves toward poles, where it falls as rain or snow and goes back to water (this doesn't count) or stays in glacier for hundreds of thousands of years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So when it's warm, we should have more $\ce{^18O}$ in ocean sediments, and less in arctic glaciers, right? So more $\ce{^16O}$ (less $\ce{^18O}$) in glaciers -&gt; warm period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, when it's cold, precipitation occurs earlier while air moves to the poles, and heavy isotope falls down earlier, on bigger latitudes. In the air that goes to the poles there is only little heavy isotope left. So more $\ce{^16O}$ (and less $\ce{^18O}$) in glaciers -&gt; cold period. This is contrary to the above. So how to figure out temperature from ice and sediments cores?&lt;/p&gt;&#xA;" OwnerUserId="109" LastEditorDisplayName="user889" LastEditDate="2015-01-23T20:15:08.927" LastActivityDate="2015-01-27T11:40:29.593" Title="How do we use oxygen isotopes as temperature proxy?" Tags="|paleoclimatology|sedimentology|glaciology|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="4318" PostTypeId="2" ParentId="4315" CreationDate="2015-01-23T16:27:24.293" Score="15" Body="&lt;p&gt;What makes you think Geothermal energy and underwater volcanoes are too weak? The mid-oceanic ridge system alone is 50000 miles long. The mean heat flow at the surface (91.6 mW/m&lt;sup&gt;2&lt;/sup&gt;) has to be accommodated somewhere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also the freezing point of brine at a depth of 5000 m is approx -40 °C.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="725" LastEditDate="2015-01-23T19:08:39.767" LastActivityDate="2015-01-23T19:08:39.767" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4319" PostTypeId="2" ParentId="4315" CreationDate="2015-01-23T18:36:02.347" Score="21" Body="&lt;p&gt;At least four things combined to prevent solid freeze-up during Ice/Slush Ball Earth periods:   &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;It takes a lower temperature to freeze water under pressure. Deep sea pressures are enormous.   &lt;/li&gt;&#xA;&lt;li&gt;Ice floats. If it sank and new ice kept forming at surface, the seas &lt;em&gt;might&lt;/em&gt; fill with ice.   &lt;/li&gt;&#xA;&lt;li&gt;The surface freezes first and acts as an approx zero-degree C barrier, slowing the progress of the ice penetration.   &lt;/li&gt;&#xA;&lt;li&gt;Thermal heat from the ocean floor at hotspots, island arcs, subduction zones, and mid-oceanic rifts is substantial, especially locally. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="2487" LastEditorUserId="1136" LastEditDate="2015-01-25T00:57:26.420" LastActivityDate="2015-01-25T00:57:26.420" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4320" PostTypeId="1" CreationDate="2015-01-23T23:37:47.490" Score="7" ViewCount="692" Body="&lt;p&gt;25°37'32.38&quot;N - latitude&#xA; 36°44'27.66&quot;E - longitude&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is between Umluj and Al Wajh on the Red Sea coast of Saudi Arabia. I can't find any kind of identification in English or Arabic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I am looking for the name and the category of this body of water and landform. To me, it seems to resemble a coral reef, but there are some islands. &lt;/p&gt;&#xA;" OwnerUserId="2489" LastEditorUserId="543" LastEditDate="2015-01-24T03:13:26.730" LastActivityDate="2021-05-02T02:07:27.610" Title="What is the name of this feature on the Red Sea coast of Saudi Arabia?" Tags="|oceanography|geography|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4321" PostTypeId="2" ParentId="4320" CreationDate="2015-01-24T01:04:11.957" Score="12" Body="&lt;p&gt;The area you describe looks like the following (from Google Maps):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/dS3xj.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the &lt;a href=&quot;http://fnad.org/Documentos/worldatlasofcora01spal.pdf&quot; rel=&quot;noreferrer&quot;&gt;World Atlas of Coral Reefs&lt;/a&gt;, a picture of this very reef appears on page 240.  The caption for it describes the feature as being the Al Wadj Bank and consisting of fringe and barrier reefs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There has been a relatively recent study of coral reefs along the Saudi Arabian Red Sea coast, of particular emphasis on reefs between the cities of Haql and Yanbu, published in the paper &lt;a href=&quot;http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.381.2751&amp;amp;rep=rep1&amp;amp;type=pdf&quot; rel=&quot;noreferrer&quot;&gt;The Present Status of the Red Sea Coral Reefs between Haql and Yanbu, Saudi Arabia&lt;/a&gt; (Hariri, 2012).&#xA;In the article, they describe that in terms of Red Sea reefs:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Island fringing reefs exist between the Al Wajh Bank to Umluj&lt;/li&gt;&#xA;&lt;li&gt;Reticulate patch reefs, composed of interconnected networks of reef matrix separated by sand also are documented to occur in the area.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;The literature seems to use both Al Wajh and Al Wadj for the spelling.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-01-24T01:23:47.127" LastActivityDate="2015-01-24T01:23:47.127" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4322" PostTypeId="1" CreationDate="2015-01-24T01:34:31.987" Score="4" ViewCount="1417" Body="&lt;p&gt;I recently started using the Climate Forecast System Reanalysis (CFSR) 6-hourly products (&lt;a href=&quot;http://rda.ucar.edu/datasets/ds093.0/&quot; rel=&quot;nofollow&quot;&gt;http://rda.ucar.edu/datasets/ds093.0/&lt;/a&gt;), and I noticed many values of relative humidity are negative. Is this an error in the dataset? If not, how should I interpret negative values?&lt;/p&gt;&#xA;" OwnerUserId="2490" LastEditorUserId="192" LastEditDate="2015-01-26T15:50:32.150" LastActivityDate="2017-02-25T11:51:26.060" Title="Negative values of relative humidity in CFSR" Tags="|meteorology|models|open-data|" AnswerCount="1" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="4323" PostTypeId="2" ParentId="4306" CreationDate="2015-01-24T02:05:04.333" Score="3" Body="&lt;p&gt;I had a rather difficult time telling how the rest of the cloud structure looks; however, I would tend to believe your weather-enthusiast friend might be correct.&#xA;&lt;p&gt;&#xA;A &lt;a href=&quot;https://en.wikipedia.org/wiki/Wall_cloud&quot; rel=&quot;nofollow&quot;&gt;wall cloud&lt;/a&gt; - rotating or not - can also be known as a pedestal cloud and is made up of cumulonimbus clouds; generally forming in the strongest part of the storm.&#xA;From what I can tell in the picture and judging by the weather that came from it; it sounds like it was a non-rotating wall cloud. &lt;a href=&quot;http://www.weather.com/news/news/thats-not-a-tornado-20130307&quot; rel=&quot;nofollow&quot;&gt;Here&lt;/a&gt; is an additional reference page that may help you identify it.&lt;/p&gt;&#xA;" OwnerUserId="342" LastActivityDate="2015-01-24T02:05:04.333" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4324" PostTypeId="1" AcceptedAnswerId="4331" CreationDate="2015-01-24T13:37:58.827" Score="10" ViewCount="197" Body="&lt;p&gt;As can be seen in the below sequence of NOAA images spanning 15 hours (most recent at top), in extreme eastern Lake Superior the surface water (but not bottom water) temperature increased dramatically in a localized area.  Can anyone confirm or rule out that this is a real event?  If it is real, what is the explanation?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.glerl.noaa.gov/res/glcfs/glcfs.php?lake=s&amp;amp;ext=swt&amp;amp;type=N&amp;amp;hr=00&quot; rel=&quot;nofollow noreferrer&quot;&gt;Link to source and additional information&lt;/a&gt; (Additional information includes lake-bottom temperature maps and additional time points)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/5VrjG.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/YqHjM.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/dve76.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2015-01-24T14:01:07.893" LastActivityDate="2015-01-26T16:32:01.220" Title="Sudden Localized Surface Water Temperature Increase In Eastern Lake Superior, Canada" Tags="|temperature|water|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4325" PostTypeId="2" ParentId="878" CreationDate="2015-01-24T22:57:42.980" Score="9" Body="&lt;p&gt;One method of earthquake prediction that is being actively studied are radioactive radon isotope anomalies at the surface preceding an earthquake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the article &lt;a href=&quot;http://cdn.intechopen.com/pdfs-wm/30709.pdf&quot; rel=&quot;noreferrer&quot;&gt;Radon as an Earthquake Precursor –&#xA;Methods for Detecting Anomalies&lt;/a&gt; (Gregorič et al.), the radon isotope $\ce{^222Rn}$ originates from the radioactive decay of $\ce{^226Ra}$ as part of the $\ce{^238U}$ decay chain that occurs naturally in varying degrees in the Earth's crust.  Due to the relatively short half-life of the $\ce{^222Rn}$ isotope.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gregorič et al. explains that the altered stress-strain dynamics before an earthquake alters the transport of &quot;geogas&quot;, which consists of carrier volatiles (e.g. $\ce{CO2}$, $\ce{CH4}$) and rarer gases within (including $\ce{Rn}$) via grounwater (liquid-phase advection), gas flow through cracks and fissures (gas-phase advection), or by quick 'bubble flow' via being carried on buoyant 'bubbles' through aquifers and water filled fractures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, this method is highly dependent on he amount of the amount of the radiogenic source already present, and factors such as soil grain size and meteorological parameters (e.g. soil moisture, rainfall, air pressure and temperature) can affect the concentrations of $\ce{^222Rn}$ at the surface, research is ongoing to determine the seismic source vs meteorological sources of radon emissions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Observations presented in the paper &lt;a href=&quot;http://tao.cgu.org.tw/pdf/v214p685.pdf&quot; rel=&quot;noreferrer&quot;&gt;Radon Monitoring in Soil Gas and Ground Water for Earthquake&#xA;Prediction Studies in North West Himalayas, India&lt;/a&gt; (Singh et al. 2010) found some correlation between surface measurements of radon and he occurrences of earthquakes, but confirmed that these were significantly affected by meteorological events and also stated that monitoring of other carrier (and rare) gases is required to potentially more accurately predict an earthquake. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a very recent paper, &lt;a href=&quot;http://eps.upo.es/martinez/papers/CAGEO14_Patterns_PUBLISHED.pdf&quot; rel=&quot;noreferrer&quot;&gt;Detecting precursory patterns to enhance earthquake prediction in&#xA;Chile&lt;/a&gt; (Florido et al. 2015) also state that in Chile, one of the recognised precursors are radon gas fluctuations occurring in the soil, groundwater and air.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-01-26T09:00:34.793" LastActivityDate="2015-01-26T09:00:34.793" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4326" PostTypeId="1" AcceptedAnswerId="4327" CreationDate="2015-01-25T12:01:45.930" Score="14" ViewCount="700" Body="&lt;p&gt;When discussing a hypothetical world without oceans and just forest it occured to me that I wasn't so sure there would be any rain in the first place, due to the lack of oceans. Searching on Google however I found out that trees transpire a whole lot more than I thought, but I was unable to find a run down of how much water in rain forest rains come from the oceans and how much comes 'directly' from the rain forest itself.&lt;/p&gt;&#xA;" OwnerUserId="2497" LastEditorUserId="56" LastEditDate="2015-01-27T00:54:19.097" LastActivityDate="2020-09-26T03:29:41.353" Title="Where does the water from rain in rain forests come from?" Tags="|water|land-surface|forest|water-vapour|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4327" PostTypeId="2" ParentId="4326" CreationDate="2015-01-25T12:23:09.427" Score="10" Body="&lt;p&gt;Leaves, mostly. Photosynthesis requires carbon dioxide, and it gets it via stomata - small controllable pores in the leaf. When the stomata open, water goes out, because the air is generally drier than the interior of the leaf. Water in the leaves is drawn up from the roots, via the xylem, using the suction from the lost water in the leaves, and also acting as a capillary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for how much water comes from transpiration, Brustaert (2005) includes a list of estimates of global annual evapotranspiration from the land that range from &lt;strong&gt;0.42-0.54 my$^{-1}$&lt;/strong&gt; (averaged over all 1.49×10$^8$ km$^2$), and 1.18-1.4 my$^{-1}$ for the ocean (3.61×10$^8$ km$^2$). That 6.22×10$^{13}$-7.99×10$^{13}$ tonnes of water or &lt;strong&gt;62.2-79.9 petatonnes&lt;/strong&gt;, compared to 425-505 petatonnes for the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, for Earth, the land is something like an sixth of the total evaporation. Keep in mind that that includes desert areas. A rainforest planet would have significantly higher evaporation than that, per square meter. For example, Malhi et al. (2002) calculate evapotranspiration over the rainforest in the Amazon at 1.12 my$^{-1}$. That is much closer to ocean rates than average land rates. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Brutsaert, W., 2005. &lt;em&gt;Hydrology: An Introduction&lt;/em&gt;, Cambridge University Press.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Malhi, Y. et al., 2002. Energy and water dynamics of a central Amazonian rain forest. Journal of Geophysical Research: Atmospheres, 107(D20), p.8061.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="56" LastEditorUserId="56" LastEditDate="2015-01-25T13:14:34.277" LastActivityDate="2015-01-25T13:14:34.277" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="4328" PostTypeId="2" ParentId="4309" CreationDate="2015-01-25T14:02:27.360" Score="14" Body="&lt;p&gt;On a broader scale the ITCZ and monsoons are related. This is because the global circulation shifts as a result of the tilt of the earth's axis relative to the orbit around the sun. In northern hemisphere summer, the northern hemisphere is tilted towards the sun and receives more radiation (energy) than the southern, and vice versa for northern winter, The southern hemisphere is affected in the same way. Without the tilt we would not experience any seasons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the tropics the largest amount of energy reaches the region where the sun is at the zenith. In northern summer this region is north of the equation, where as in winter it is at the south. At the spring and fall equinox it coincides with the equator. Hence the region of maximum energy input wanders seasonally to the north and south of the equator.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Climatologically the region with maximum energy input sets up a circulation in the form of so-called &lt;a href=&quot;http://en.wikipedia.org/wiki/Hadley_cell&quot;&gt;Hadley cells&lt;/a&gt; where warm air rises where it is heated the most and then transported at elevation to the north and south. At the location of upward air flow formation of convective clouds yielding precipitation becomes the norm. This zone to which ground winds flow towards the region of maximum energy influx is the ITCZ and because the zone of maximum solar energy influx wanders, the ITCZ flows. The zone is fairly wide so the regions around the equator sees the effects of tropical precipitation more or less without seasonality, actually two rain periods and two drier periods as the ITCZ moves once to the north and once to the south over the region each year. Away from the equator the resulting period of precipitation becomes more and more marked as one moves to the north and south resulting in strongly seasonal rains. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This movement of the large scale circulation on the earth produces several associated effects and the different monsoons are such phenomena. There are several monsoons on the earth created by weather phenomena typical for the specific region. The Asian monsoon is perhaps the most known. The specific conditions leading up to this monsoon is found in the high elevation Tibetan plateau. During the northern winter the plateau sees a larger high pressure forming which generates winds flowing south over India and causing a dry climate. During the northern summer large parts are heated generating a low pressure over land which draws in moist air from the sea yielding strong precipitation. Hence the monsoon follows the same seasonality as is seen in the wander of the ITCZ but the cause for the regional change in seasonal wind and precipitation pattern has a different cause.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to understand the large scale weather systems and their seasonal patterns, you must start by understanding how solar energy drives the atmospheric circulation. This causes a specific and typical pattern which is locally disrupted by the distribution of land and oceans on the earth. Land masses can be heated more and more quickly than oceans on a seasonal basis, land masses also includes topography that can impede the atmospheric circulation, so it it perhaps obvious that land masses contribute on regional and local scales.&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2015-01-25T14:02:27.360" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4329" PostTypeId="1" AcceptedAnswerId="4330" CreationDate="2015-01-26T10:25:15.873" Score="8" ViewCount="3488" Body="&lt;p&gt;In the calculation of scalar moment magnitude of an earthquake we have the formula&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$M_0=\mu AD$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$\mu$ is the shear modulus of the rocks involved in the earthquake (in Pa)&lt;/li&gt;&#xA;&lt;li&gt;$A$ is the area of the rupture along the geologic fault where the earthquake occurred (in m&lt;sup&gt;2&lt;/sup&gt;), and&lt;/li&gt;&#xA;&lt;li&gt;$D$ is the average displacement on $A$ (in m).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In many cases the displacement can occur in the subsurface.In order to predict the moment magnitude of such earthquakes the value of $D$ must be estimated. How is this process carried out ?&lt;/p&gt;&#xA;" OwnerUserId="594" LastEditorUserId="32" LastEditDate="2015-01-27T19:39:05.267" LastActivityDate="2015-01-27T19:39:05.267" Title="Calculating the displacement of a fault" Tags="|geophysics|seismology|earthquakes|tectonics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4330" PostTypeId="2" ParentId="4329" CreationDate="2015-01-26T15:45:22.033" Score="3" Body="&lt;p&gt;The process is carried out by solving an &lt;a href=&quot;http://en.wikipedia.org/wiki/Inverse_problem&quot; rel=&quot;nofollow&quot;&gt;&quot;inverse problem&quot;&lt;/a&gt; and there are many ways to estimate the moment depending on the observable. For example if you have some measurements of ground deformation following the earthquake (using GPS/InSAR) then by combing a physics based model, with an optimizer, you can estimate the area/slip distribution that best explains the observations. Once you know the area/slip distribution then you can estimate the moment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The physical models can be simple or complex (e.g., semi-analytical or fully numerical). Same goes for the optimizer (local or global). For computationally expensive numerical models global optimization is typically not feasible. For local optimization you need a 'reasonable' initial model.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2015-01-26T15:53:17.923" LastActivityDate="2015-01-26T15:53:17.923" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4331" PostTypeId="2" ParentId="4324" CreationDate="2015-01-26T16:32:01.220" Score="8" Body="&lt;p&gt;NOAA revised the data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The map below is for the same date and time as the first map in the question, but with the anomaly gone.  So I'll have to assume the event wasn't real.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/bWC4T.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2015-01-26T16:32:01.220" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4332" PostTypeId="2" ParentId="170" CreationDate="2015-01-26T20:30:16.167" Score="6" Body="&lt;p&gt;Using Matlab, you can do ncgeodataset (&lt;a href=&quot;http://code.google.com/p/nctoolbox/wiki/ncgeodataset&quot; rel=&quot;nofollow&quot;&gt;http://code.google.com/p/nctoolbox/wiki/ncgeodataset&lt;/a&gt;) to subsample the netcdf without having to download large datasets. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For instance, &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;nc = ncgeodataset('http://thredds.jpl.nasa.gov/thredds/dodsC/ncml_aggregation/OceanTemperature/ghrsst/aggregate__ghrsst_JPL_OUROCEAN-L4UHfnd-GLOB-G1SST_OI.ncml'); &#xA;gvar = nc.geovariable('analysed_sst'); &#xA;s.time={'20-May-2012', '24-May-2012'}; &#xA;s.lat=[40 41.5]; &#xA;s.lon=[0 2.0]; &#xA;sub = gvar.geosubset(s); % Subset method &#xA;pcolor(sub.grid.lon,sub.grid.lat,double(squeeze(sub.data(1,:,:)))-273.15);&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="111" LastEditorUserId="87" LastEditDate="2015-01-27T07:32:52.703" LastActivityDate="2015-01-27T07:32:52.703" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4333" PostTypeId="1" CreationDate="2015-01-26T21:25:19.780" Score="10" ViewCount="2827" Body="&lt;p&gt;I am trying to understand the behavior of oxygen dissolved in seawater. I have always been under the impression that if a gas is in equilibrium between its gaseous and aqueous forms, that it will always have the same partial pressure in the air as in the water. For example, both air and air saturated seawater have a pO2 of 21.227 kPa (101.325 kPa x 20.95%). I recently, however, came across &lt;a href=&quot;http://www.presens.de/fileadmin/user_upload/downloads/Tools_Utilities/Oxygen_Unit_Calculation_dv1_1.xls&quot;&gt;this&lt;/a&gt; tool from a company that creates dissolved O2 measuring devices which indicates that temperature has an effect on this relationship. It indicates that if atmospheric pressure is 101.3 kPa (pO2 in the atmosphere = 21.222 kPa) then the pO2 in seawater could be anything from 21.094 kPa at 0*C to 20.331 at 30*C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this is true, what causes this relationship? How can I calculate expected seawater pO2 given atmospheric pressure and temperature?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bonus if you know of a function or package in R that could do this. Perhaps in the &lt;code&gt;marelac&lt;/code&gt; package?&lt;/p&gt;&#xA;" OwnerUserId="2502" LastActivityDate="2015-01-27T13:01:16.070" Title="Does temperature affect partial pressure of gas dissolved in water?" Tags="|atmosphere|ocean|barometric-pressure|" AnswerCount="1" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4334" PostTypeId="5" CreationDate="2015-01-27T01:00:56.847" Score="0" Body="&lt;p&gt;The &lt;strong&gt;land surface&lt;/strong&gt; is a major component of the Earth's hydrocycle and biosphere. It has significant impacts on the atmosphere and climate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The land surface consists of various terrains, and biomes, from mountainous alpine heath, to coastal rainforest, to wetlands, to polar tundra and ice-sheets. The land surface also includes open water in the form of lakes and rivers.&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="2958" LastEditDate="2018-11-09T16:49:51.577" LastActivityDate="2018-11-09T16:49:51.577" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="4335" PostTypeId="4" CreationDate="2015-01-27T01:00:56.847" Score="0" Body="The **land surface** is a major component of the Earth's hydrocycle and biosphere. It has significant impacts on the atmosphere and climate." OwnerUserId="56" LastEditorUserId="56" LastEditDate="2015-01-27T03:38:39.230" LastActivityDate="2015-01-27T03:38:39.230" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4336" PostTypeId="5" CreationDate="2015-01-27T01:21:34.360" Score="0" Body="&lt;p&gt;The &lt;strong&gt;hypothetical&lt;/strong&gt; tag is used for questions about processes that are unlikely to occur, but which may act as useful thought experiments and provide general insight into the processes in question.&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="56" LastEditDate="2015-01-27T03:37:34.367" LastActivityDate="2015-01-27T03:37:34.367" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4337" PostTypeId="4" CreationDate="2015-01-27T01:21:34.360" Score="0" Body="The hypothetical tag is used for questions about processes that are unlikely to occur, but which may act as useful thought experiments and provide general insight into the processes in question." OwnerUserId="56" LastEditorUserId="56" LastEditDate="2015-01-27T03:37:44.727" LastActivityDate="2015-01-27T03:37:44.727" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4339" PostTypeId="2" ParentId="4317" CreationDate="2015-01-27T09:09:14.950" Score="5" Body="&lt;p&gt;This is somewhat a general answer.  According to the Royal Chemical Society webpage &lt;a href=&quot;http://www.rsc.org/chemistryworld/2013/01/climate-proxies&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chemical climate proxies&lt;/a&gt; (Evans, 2013), the rarer and heavier $\ce{^18O}$ isotope in water generally evaporates after and condenses (and precipitates) out earlier than the lighter and more common $\ce{^16O}$ isotope, shown in the diagram below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/xEiXQ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: University of Michigan's page &lt;a href=&quot;http://www.globalchange.umich.edu/globalchange1/current/lectures/kling/paleoclimate/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Past Climates on Earth&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The colder the environment, the quicker the atmospheric water vapour condenses, hence the quicker the $\ce{^18O}$ isotope is depleted, giving a lower ratio of $\ce{^18O}$ to $\ce{^16O}$ (referred to by the RSC page as $\delta{\ce{^18O}}$) by the time it reaches the poles.  In contrast, a warmer environment would mean that the water vapour condenses later and slower, meaning that less $\ce{^18O}$ laden water vapour condenses, resulting in a higher $\delta{\ce{^18O}}$ value.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short, it is not so much of the amount of $\ce{^16O}$, but rather the ratio of $\ce{^18O}$ to $\ce{^16O}$ isotopes present, otherwise known as $\delta{\ce{^18O}}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following Earth Observatory diagram demonstrates the present-time process, showing the differences between warm and cold environments:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/HbzYI.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: Earth Observatory's page: &lt;a href=&quot;http://earthobservatory.nasa.gov/Features/Paleoclimatology_OxygenBalance/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Paleoclimatology: The Oxygen Balance&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-01-27T11:40:29.593" LastActivityDate="2015-01-27T11:40:29.593" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4340" PostTypeId="2" ParentId="4333" CreationDate="2015-01-27T12:55:36.020" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;blockquote&gt;&#xA;    &lt;p&gt;have always been under the impression that if a gas is in equilibrium between its gaseous and aqueous forms, that it will always have the same partial pressure in the air as in the water. For example, both air and air saturated seawater have a pO2 of 21.227 kPa (101.325 kPa x 20.95%).&lt;/p&gt;&#xA;  &lt;/blockquote&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That's a very bad impression, and your example is just not the case. Oxygen solubility in water at 0°C at one atmosphere of pressure is 14.6 mg/liter in fresh water, 11.2 mg/liter in salt water (35 g/kg salt). Those values correspond to 1036 pascals and 794 pascals, respectively.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oxygen solubility in water is highly temperature and pressure dependent. Like most (but definitely not all) gases, oxygen solubility in water is greatest at 0°C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oxygen solubility comes very close to following Henry's law for typical pressures. Henry's law says that &quot;at a constant temperature, the amount of a given gas that dissolves in a given type and volume of liquid is directly proportional to the partial pressure of that gas in equilibrium with that liquid.&quot; The constant of proportionality is not constant. It instead is a function of temperature and the nature of the liquid.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2015-01-27T13:01:16.070" LastActivityDate="2015-01-27T13:01:16.070" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4341" PostTypeId="1" CreationDate="2015-01-27T17:16:23.320" Score="14" ViewCount="382" Body="&lt;p&gt;While I was browsing Mars on Google Earth, I stumbled upon an interesting feature on one of the slopes of Valles Marineris. The feature seems unique in the sense that I couldn't find any similar element on the valley.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/lz9AR.jpg&quot; alt=&quot;Top View&quot;&gt; &lt;img src=&quot;https://i.stack.imgur.com/IwQB2.jpg&quot; alt=&quot;3D Front View&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It made me think of sand that just fell from the clifftop or the veins of water that have already been observed on Mars (such as &lt;a href=&quot;http://www.wired.com/2011/03/happy-birthday-mro/#slideid-591036&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.wired.com/2011/03/happy-birthday-mro/#slideid-591036&lt;/a&gt;). But it doesn't seems to match completely with this explanation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does any of you have seen this before from current Mars research or from similar phenomenon on Earth?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Coordinates :&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;14°32'25.35&quot;S 54°15'12.43&quot;O&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Google GMail direct link :&#xA;&lt;a href=&quot;https://www.google.ch/maps/space/mars/@-14.5528401,-54.2675885,41353a,20y,4.75h,0.44t/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.google.ch/maps/space/mars/@-14.5528401,-54.2675885,41353a,20y,4.75h,0.44t/data=!3m1!1e3&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2506" LastEditorDisplayName="user889" LastEditDate="2015-01-31T04:04:05.663" LastActivityDate="2015-02-07T01:25:24.490" Title="What is this strange feature on Mars in Valles Marineris" Tags="|geophysics|planetary-science|groundwater|desert|mars|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4342" PostTypeId="2" ParentId="4307" CreationDate="2015-01-28T02:38:53.397" Score="7" Body="&lt;p&gt;The fact that these three features are parallel may be somewhat coincidental, although we can suspect that tectonic forces have influenced their morphology. The crust under the Arctic Sea is one of the least understood regimes in the world. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is changing - whichever country can prove that their nation's continental shelf extends along one or more of these ridges can, according to the United Nations, claim subsurface oil and minerals.  Candidate countries include Russia, Canada, Norway, the USA, and Greenland/Denmark. As a result, there has been recent seismic and geological work in the area, though some of the reports are nuanced in an effort to bolster nationalistic claims.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Alpha Ridge&lt;/strong&gt; is a volcanic ridge extension off the continent from&#xA;   Ellesmere Island, Canada.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Lomonosov Ridge&lt;/strong&gt; seems to be ancient continental crust and is likely an&#xA;   extension of Canada's continental shelf. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Gakkel Ridge&lt;/strong&gt; accompanies a spreading seafloor rift which extends north from the mid-Atlantic ridge. It has the slowest divergence of any mid-ocean ridge in the world (less than a centimeter a year).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is how the three ridges appear in cross-section:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/xTmVs.png&quot; alt=&quot;enter image description here&quot;&gt;&#xA;   (Source: &lt;a href=&quot;http://en.wikipedia.org/wiki/File:BrnBld_BeringToFram.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://en.wikipedia.org/wiki/File:BrnBld_BeringToFram.svg&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are &lt;strong&gt;two basins&lt;/strong&gt; in the Arctic. The part closest to Europe, the &lt;strong&gt;Eurasian Basin&lt;/strong&gt;, formed when the mid-Atlantic Ridge grew to the north, becoming the Gakkel Ridge. It divided a long, narrow strip of continental crust from the Barents Shelf, the Lomonosov Ridge. This action resulted in Lomonosov's parallel orientation to the Gakkel. Since the Alpha Ridge is further to the west and within the &lt;strong&gt;Amerasian Basin&lt;/strong&gt;, it might be a stretch to suggest it is related to the Gakkel. It's parallel orientation is more likely an accident and in time it may rotate with respect to the other two ridges.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For an accessible and lucid description of the Arctic's tectonics, &lt;a href=&quot;http://scientistatwork.blogs.nytimes.com/2011/09/15/northern-lights-on-the-midnight-watch&quot; rel=&quot;nofollow noreferrer&quot;&gt;this piece&lt;/a&gt; by Bernard Coakley in the &lt;em&gt;New York Times&lt;/em&gt; is quite good:  &lt;a href=&quot;http://scientistatwork.blogs.nytimes.com/2011/09/15/northern-lights-on-the-midnight-watch&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://scientistatwork.blogs.nytimes.com/2011/09/15/northern-lights-on-the-midnight-watch&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2487" LastEditorUserId="87" LastEditDate="2015-01-28T13:15:18.127" LastActivityDate="2015-01-28T13:15:18.127" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4343" PostTypeId="2" ParentId="2823" CreationDate="2015-01-28T15:44:02.610" Score="8" Body="&lt;p&gt;First OLR map is usually graded in flux units (W/m&lt;sup&gt;2&lt;/sup&gt;) thus it is quantitative data, not just a visual picture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clouds themselves are not a very reliable indicator of high convection and thunderstorm activity. They could form elsewhere and get blown into a dry region. Also with an OLR map students would not be distracted with the shapes of the clouds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;AIRS OLR products combine infrared and microwave data. Microwave data helps to distinguish between areas of strong convection and nonprecipitating clouds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a typical OLR product from GOES satellite (taken from Hai-Tien Lee presentation). Such images can be generated with 15 minute interval so the movement of the MJO pattern can be easily observed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/qAzzM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="2511" LastEditorUserId="725" LastEditDate="2015-01-30T21:38:56.617" LastActivityDate="2015-01-30T21:38:56.617" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="4344" PostTypeId="1" CreationDate="2015-01-28T22:34:04.727" Score="14" ViewCount="200" Body="&lt;p&gt;A quick skim of the regional chapters in AR5 shows predicted changes to average temperature and precipitation.  If I understand (in rough terms) the modelling methodologies used, a variety of models (an ensemble) are run many times each, each with different initial conditions.  The output is $\mathbf{Y}_{xyztmi}$ where $xyzt$ are coordinates and time, $m$ is a model, $i$ is one run of a specific model, and $Y$ is some modeled climate variable.  The ensemble mean prediction at time $t$ for gridcell $xyz$ is just the average over $m$ and $i$.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The variance of $Y_{mi}$ however is comprised both of real variability in the climate system, and model error.  &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/JCLI3735.1&quot;&gt;This paper&lt;/a&gt; (9 years old now) suggests that drivers of intra-annual precipitation are really hard to model with GCMs.  Can it be done effectively with RCMs?  Are there dynamical arguments suggesting changes to higher moments of climate parameters (particularly in the tropics)?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Changes to distributions are commonly talked-about in the impacts literature, but I haven't come across concrete projections of changes to distributions from the climate science community.  Citations welcome.&lt;/p&gt;&#xA;" OwnerUserId="545" LastEditorUserId="6298" LastEditDate="2021-09-02T02:39:37.997" LastActivityDate="2021-09-02T02:39:37.997" Title="Will global climate change alter the interannual and/or intraseasonal variance of temperature and/or precipitation?" Tags="|climate-change|temperature|climate-models|precipitation|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="4345" PostTypeId="1" AcceptedAnswerId="4347" CreationDate="2015-01-29T10:30:59.113" Score="11" ViewCount="132" Body="&lt;p&gt;Why is there a bend in the Lomonosov Ridge?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a supplementary question to that asked by Sabre Tooth in &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4307/what-is-the-tectonic-explanation-for-parallel-ridges-in-the-arctic-ocean&quot;&gt;What is the tectonic explanation for parallel ridges in the Arctic ocean&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-01-30T11:44:31.247" Title="Why is there a bend in the Lomonosov Ridge?" Tags="|geophysics|plate-tectonics|arctic|ocean-ridge|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4346" PostTypeId="1" CreationDate="2015-01-30T06:34:27.440" Score="14" ViewCount="6102" Body="&lt;p&gt;I know plants form a critical part of the earth's biosphere, including molecular oxygen production. Molecular oxygen makes up &lt;a href=&quot;http://www.space.com/17683-earth-atmosphere.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;~20%&lt;/a&gt; of our atmosphere.  How much of the earth's molecular oxygen in the atmosphere is due to plants? Is there a minimal level of plant life necessary to maintain levels of oxygen so that land mammals can live? Also, are land plants mostly important or are underwater plants a significant source of atmospheric oxygen?&lt;/p&gt;&#xA;" OwnerUserId="1260" LastEditorUserId="1260" LastEditDate="2019-05-01T03:10:06.007" LastActivityDate="2020-12-19T20:47:52.833" Title="How much of earth's molecular oxygen in the atmosphere is due to plants?" Tags="|atmosphere|biomass|biogeochemistry|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4347" PostTypeId="2" ParentId="4345" CreationDate="2015-01-30T11:44:31.247" Score="6" Body="&lt;p&gt;Firstly, just including the map of the ridges, in particular the Lomonosov Ridge and the characteristic bend visible near the North Pole:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/taJgy.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Lomonosov_Ridge&quot; rel=&quot;noreferrer&quot;&gt;Image Source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Based on magnetic anomaly observations, Cochran et al. (2006) theorise that the bend visible in the Lomonosov Ridge formed over a 3-6 million year period where there may have been a non-transform offset connecting a seafloor spreading region in the west Eurasian Basin with the continued continental rifting to the east, that continued propogating eastward resulting in the area of oblique spreading.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the Cochran et al. article, the tectonic spreading occurred around 53-56 million years ago, which according to models from Shephard et al. (2013) was associated with the opening of the Eurasia Basin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Note: Cochran et al. refer to the eastern side as that on the Siberian side of the 'bend' and consequently, the western side being in the direction of North America.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Specifically, Cochran et al. conclude that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The prominent bend in the Lomonosov Ridge near the Pole corresponds to an approximately 50 km offset in Marvin Spur. The offset of the marginal ridge is consistent with the presence of a short extensional segment located between two long transforms.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cochran et al. 2006, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2005GC001114/full&quot; rel=&quot;noreferrer&quot;&gt;Morphology and structure of the Lomonosov Ridge, Arctic Ocean&lt;/a&gt;, &lt;em&gt;Geochemistry, Geophysics, Geosystems&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shephard et al. 2013, &lt;a href=&quot;http://earthbyte.org/Resources/Pdf/Shephard_etal_2013_Arctic_plate_model_Earth-Sci_Rev.pdf&quot; rel=&quot;noreferrer&quot;&gt;The tectonic evolution of the Arctic since Pangea breakup:&#xA;Integrating constraints from surface geology and geophysics&#xA;with mantle structure&lt;/a&gt; &lt;em&gt;Earth-Science Reviews&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2015-01-30T11:44:31.247" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4348" PostTypeId="2" ParentId="4346" CreationDate="2015-01-30T12:19:24.523" Score="8" Body="&lt;p&gt;The oxygen in the atmosphere was produced by cyanobacteria during the &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Oxygenation_Event&quot; rel=&quot;noreferrer&quot;&gt;Great Oyxgenation Event&lt;/a&gt;, around 2.3 billion years ago. Cyanobacteria produced &amp;amp; still, produces, to a lesser extent, oxygen by photosynthesis. Plants did not exist during the Great Oxygenation Event, but these day plants replenish atmospheric oxygen by removing carbon dioxide by photosysnthesis, like cyanobacteria. According to David Biello, &lt;a href=&quot;http://www.scientificamerican.com/article/origin-of-oxygen-in-atmosphere/&quot; rel=&quot;noreferrer&quot;&gt;The Origin of Oxygen in the Earth's Atmosphere&lt;/a&gt; the production of oxygen by cyanobacteria during the Great Oxygenation Event took one billion years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During the Carboniferous period, about 350 million years ago, the amount of oxygen in the atmosphere increased to 30% because the rate of burial of organic matter prevented it from reacting with atmospheric oxygen, &lt;a href=&quot;http://newworlds.colorado.edu/search/o2.htm&quot; rel=&quot;noreferrer&quot;&gt;History &amp;amp; Significance of Oxygen in the Atmosphere&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to Wallace S. Broecker our atmospheric oxygen supplies are vast: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Simply put, our atmosphere is endowed with such an enormous reserve of this gas that even if we were to burn all our fossil fuel reserves, all our trees, and all the organic matter stored in soils, we would use up only a few percent of the available $\ce{O2}$. No matter how foolishly we treat our environmental heritage, we simply don't have the capacity to put more than a small dent in our $\ce{O2}$ supply. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;http://www.columbia.edu/cu/21stC/issue-2.1/broecker.htm&quot; rel=&quot;noreferrer&quot;&gt;Atmospheric oxygen - Broecker&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorDisplayName="user889" LastEditDate="2015-01-30T12:21:39.033" LastActivityDate="2015-01-30T12:21:39.033" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4349" PostTypeId="1" CreationDate="2015-01-30T13:11:19.807" Score="8" ViewCount="137" Body="&lt;p&gt;In atmospheric physics we use often a variety of vertical coordinates, $z$ the height above some reference surface, or $r$ as distance from the planetary center.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However sometimes it simplifies the equations we want to solve by using other coordinates, Pressure $P$, LogPressure, Potential temperature $\theta$,...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One vertical coordinate I want to specifically ask about is the shallow water height. It is defined by looking at the hydrostatic stability approximation&#xA;$$ \frac{\partial P}{\partial z} = \rho_0 g$$&#xA;then integrating over a variable height $h(x,y)$ so that we arrive at constant pressure $P(h)$ we get easily&#xA;$$P(z)=\rho_0 g (h-z)+P(h) $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So $h(x,y)$ is now the variable height between two Iso-Pressure surfaces in some planetary fluid.&lt;br&gt;&#xA;Now we can express the navier-stokes-equation, mass equation, thermodynamic equation in terms of $h$. I guess this will be very familiar to those who could answer me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is now:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Assuming no vertical mixing (=geostrophic movement on isobaric surfaces), can I now build a vertical model of the planet consisting of a multitude of shallow fluid-layers? Namely I'd take $h1(x,y)$ as between $p1$ and $p2$, $h2(x,y)$ between $p2$ and $p3$,... and thus build up and atmosphere of a gas giant between $\sim 10^{-1} bar$ and several $10^2$ bars.&lt;/li&gt;&#xA;&lt;li&gt;And more important: when could this approach be totally wrong?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Naively I'd expect this to be OK in my case, as I'm still effectively integrating over the whole planet, but I hoped for some experts opinion on this. &lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="489" LastEditDate="2015-01-30T14:21:36.177" LastActivityDate="2015-02-02T09:21:37.013" Title="Shallow water height as vertical coordinate" Tags="|atmosphere-modelling|fluid-dynamics|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="4350" PostTypeId="1" CreationDate="2015-01-30T22:17:46.013" Score="7" ViewCount="227" Body="&lt;p&gt;Related to an earlier question, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4293/what-is-the-geochemical-source-for-the-helium-detected-in-deep-arctic-explosive&quot;&gt;What is the geochemical source for the helium detected in deep Arctic explosive eruptions?&lt;/a&gt;, where it is stated in the linked article that there is evidence of explosive volcanism deeper than 3km depth - the evidence coming from both seismic and petrological observations.  The article &lt;a href=&quot;http://news.nationalgeographic.com.au/news/2003/06/0625_030625_gakkelridge_2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hotbed of Volcanic Activity Found Beneath Arctic Ocean&lt;/a&gt; suggests that, as the article title alludes to, that the region has many hydrothermal vents and explosive centres.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These types of eruptions are not thought to be able to occur at depths greater than 3km, according to the article &lt;a href=&quot;http://news.nationalgeographic.com.au/news/2008/06/080626-arctic-volcano.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Arctic Volcanoes Found Active at Unprecedented Depths&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is the mechanism for deep-sea explosive volcanism of the Gakkel Ridge in the Arctic?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-01-30T22:17:46.013" Title="What is the mechanism for deep-sea volcanism of the Gakkel Ridge in the Arctic?" Tags="|volcanology|geochemistry|arctic|sea-floor-spreading|pyroclastic-flows|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4351" PostTypeId="2" ParentId="4350" CreationDate="2015-01-30T22:17:46.013" Score="6" Body="&lt;p&gt;There is some considerable uncertainty as the exact mechanisms. However, the recent seismicity and pyroclastic deposits detected around the ridge provide a unique opportunity to observe and model the baheviour of ultraslow spreading ridges.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the article &lt;a href=&quot;http://www.pol.gu.se/digitalAssets/1316/1316579_nature.pdf&quot;&gt;Explosive volcanism on the ultraslow-spreading&#xA;Gakkel ridge, Arctic Ocean&lt;/a&gt; (Sohn et al. 2008), to overcome the pressure of the seawater, it becomes a question of the amount of volatiles (particularly $\ce{CO2}$ available in the magma chamber to cause fragmentation resulting in the glassy pyroclastic deposits observed around the volcanic centres on the Gakkel Ridge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sohn et al. hypothesise that the ultraslow spreading nature of the Gakkel Ridge would cause long intervals between volcanic events, which in the article, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2012GC004187/full&quot;&gt;Effusive and explosive volcanism on the ultraslow-spreading Gakkel Ridge, 85°E&lt;/a&gt; (Pontbriand et al. 2012) suggest to be around 10,000 years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The long interval times allow for the accumulation of large volumes of volatiles in the upper part of the magma chambers. These would erupt periodically when the pressure in the magma chamber exceeds the deep sea-water pressure.  Models from Sohn et al. suggest that a weight fraction of 14% $\ce{CO2}$ (~75% volume fraction) would be required - a value considerably higher than those measured at most mid ocean ridges.  Pontbriand et al. estimate that $\ce{CO2}$ supersaturation in the magma chambers of the Gakkel Ridge to occur around 1500-2000 year timeframes (i.e. well within the estimated volcanism interval).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pontbriand et al. go further and suggest that one of the most important implications of the observations (and modelling) of explosive volcanism on deep-sea ultraslow spreading ridges challenge the hypothesis that eruption volume varies inversely with mid ocean ridge spreading rates.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2015-01-30T22:17:46.013" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4352" PostTypeId="2" ParentId="4289" CreationDate="2015-01-31T20:19:53.763" Score="6" Body="&lt;p&gt;Your question seems to lump at least three different phenomena together: tsunami waves(seismic sea waves), the effects of landslides near the coast, and the effects of asteroid impact into the ocean.  You might have also included rogue waves. Each of these are complex phenomena when you start considering 'realistic' boundary and initial conditions - so you should not expect a highly accurate answer from a simple model.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seismic sea waves, or waves initiated by land slide, can travel great distances across the ocean. These waves have a long wavelength and therefore may be modeled as shallow water waves. Although the height of classical shallow water wave may be limited (in theory) by the wave steepness (1:7) where the wave 'breaks' and collapses, &lt;a href=&quot;https://www.youtube.com/watch?v=haeQhHs3m_8&amp;amp;feature=youtu.be&amp;amp;app=desktop&quot; rel=&quot;noreferrer&quot;&gt;Computer models of tsunami&lt;/a&gt; are likely to be much more accurate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are primarily interested in what happens near a coastline or in a bay, then the most accurate solution will likely be a computer model that also include realistic boundary conditions. See these &lt;a href=&quot;https://www.youtube.com/watch?feature=player_embedded&amp;amp;v=FbZBR-FjRwY&amp;amp;x-yt-ts=1422579428&amp;amp;x-yt-cl=85114404&quot; rel=&quot;noreferrer&quot;&gt;computer models of a dam break and waves&lt;/a&gt; in an irregular water body.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The possible initial conditions for an asteroid impact could be so large that planetary material is ejected into orbit. The &lt;a href=&quot;http://en.wikipedia.org/wiki/Martian_meteorite&quot; rel=&quot;noreferrer&quot;&gt;Martian meteorites&lt;/a&gt; found on Earth are believed to have originated from a impact on Mars. In a large impact, the height of the rim wall might not be an accurate estimate of the maximum altitude material was actually thrown.&lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorUserId="178" LastEditDate="2015-01-31T20:28:26.170" LastActivityDate="2015-01-31T20:28:26.170" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4356" PostTypeId="1" AcceptedAnswerId="8797" CreationDate="2015-02-02T11:12:32.707" Score="11" ViewCount="79" Body="&lt;p&gt;I am interested in &lt;em&gt;in situ&lt;/em&gt; coal fires. In furtherance of this, I am hoping to find a database of Canadian mine reclamation sites, complete with incident or status reports and descriptions of specific problems. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've poked around a very small bit in the Federal Contaminated Sites Inventory, but I'm hoping there might be something a bit more specific or targeted out there -- something more like the equivalent of the United States' Abandoned Mine Load Inventory System (AMLIS) database. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any pointers? &lt;/p&gt;&#xA;" OwnerUserId="2519" LastEditorUserId="192" LastEditDate="2015-02-02T20:08:57.413" LastActivityDate="2016-09-30T16:25:36.753" Title="Canadian equivalent to AMLIS database?" Tags="|geothermal-heat|open-data|mining|canada|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4357" PostTypeId="1" AcceptedAnswerId="4360" CreationDate="2015-02-03T00:40:47.483" Score="6" ViewCount="424" Body="&lt;p&gt;A recent report estimated the probability of an earthquake greater than magnitude 7 on the southern section of the San Andreas fault at approximately 60% over the next thirty years.  How is that probability calculated?&lt;/p&gt;&#xA;" OwnerUserId="2521" LastActivityDate="2015-02-03T06:20:06.823" Title="Earthquake probabilities" Tags="|seismology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4358" PostTypeId="1" AcceptedAnswerId="4361" CreationDate="2015-02-03T01:47:51.073" Score="31" ViewCount="60197" Body="&lt;p&gt;Is it possible for rivers to freeze completely in the winter and stop flowing?  Are there known examples of this?  If yes, how large can these rivers be and where does the water go?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are several large Siberian rivers that empty into the Arctic Ocean.&lt;/p&gt;&#xA;" OwnerUserId="2522" LastActivityDate="2021-02-25T19:14:33.503" Title="Is it possible for rivers to freeze completely and stop flowing?" Tags="|temperature|rivers|water|" AnswerCount="5" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4359" PostTypeId="2" ParentId="4358" CreationDate="2015-02-03T01:52:16.543" Score="11" Body="&lt;p&gt;In a way, glaciers are just like frozen rivers. A good start on that topic comes from &lt;a href=&quot;http://water.usgs.gov/edu/earthglacier.html&quot;&gt;USGS&lt;/a&gt;. Ice (whether in a frozen river or in a glacier) is still a fluid and thus is always moving because of its own weight. A frozen river will still be a river of incredibly slow moving water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When water is not moving, first the entire volume cools down to 4C (maximum density) as the colder water keeps sinking to the bottom. Then, a thin layer at the surface starts to freeze while floating on the denser water below. By contrast, in moving water, the entire volume has to cool to 0C before freezing starts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For any river to freeze, heat must be lost at a rate that exceeds the rate of replacement.  Because of the high heat capacity of water, fast moving water (e.g., mountain cascades) will be more difficult to freeze because heat loss will be smaller than flow rate. Thus, slow moving small streams tend to freeze quickly.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2015-02-03T04:26:45.390" LastActivityDate="2015-02-03T04:26:45.390" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="4360" PostTypeId="2" ParentId="4357" CreationDate="2015-02-03T02:31:36.130" Score="6" Body="&lt;p&gt;The probabilities are generally based on long term recurrence rates. You can read about the details in the Working Group on Earthquake Probabilities page &lt;a href=&quot;http://www.wgcep.org/components-EQ_probability_model&quot; rel=&quot;nofollow&quot;&gt;Earthquake Probability Models&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The last major earthquake on Southern SAF was in 1857 which means that the average slip deficit on the fault is around ~8.0 m (the Pacific plate is sliding past at a rate of 55 mm/yr). Using empirical scaling laws you can estimate the magnitude of the earthquake that is required to release the accumulated strain. However, the 8.0 m slip deficit is an upper bound as some of the deformation in the region is accommodated by other fault systems, e.g., Elsinore and San Jacinto faults (sub-parallel to SAF) as well as the Eastern California Shear Zone which was the site of Landers/Hector Mine earthquakes in the 90s.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorDisplayName="user889" LastEditDate="2015-02-03T06:20:06.823" LastActivityDate="2015-02-03T06:20:06.823" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4361" PostTypeId="2" ParentId="4358" CreationDate="2015-02-03T06:00:59.943" Score="25" Body="&lt;p&gt;I am interpreting your question as referring to rivers with flowing water freezing as as opposed to glaciers, which are already frozen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Under current climatic conditions, small rivers can freeze throughout: from bank to bank, surface to river bed. I'm avoiding using the word solid as some people use that word when a river's surface has frozen from bank to bank. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Large rivers do not freeze &quot;through out&quot; because, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Water, ice, and snow are good insulators and poor conductors of heat.&#xA;  The portions of a lake or river that are exposed to the cold winter&#xA;  air will freeze into ice and this ice insulates the water below from&#xA;  further rapid freezing. Also contributing to the prevention of bodies&#xA;  of water freezing solid is an interesting characteristic of water.&#xA;  Like most other forms of matter, water become denser as it cools, but&#xA;  beginning at about 39°F (4°C) something odd happens - water begins to&#xA;  lose density as it gets colder, becoming least dense when it freezes&#xA;  into ice. This is why ice floats. As water becomes colder it rises to&#xA;  the top, eventually freezing to the layers of ice that are already&#xA;  there. Insulation of the water beneath is increased as the ice&#xA;  thickens so cooling of the water beneath slows.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;From &lt;strong&gt;The Great Land of Alaska&lt;/strong&gt;: &lt;a href=&quot;http://www.greatlandofalaska.com/reference/faq.html#freezesolid&quot; rel=&quot;noreferrer&quot;&gt;Why don't lakes and rivers freeze solid?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, while water is flowing its potential energy is constantly being converted to heat energy that resists freezing on the molecular level and subsequent crystallization.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For flowing water to freeze, the temperature would have to be exceptionally cold.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="6093" LastEditDate="2016-11-25T04:36:14.047" LastActivityDate="2016-11-25T04:36:14.047" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4362" PostTypeId="1" AcceptedAnswerId="4363" CreationDate="2015-02-03T08:34:40.433" Score="6" ViewCount="915" Body="&lt;p&gt;What events took place in our Solar System which led to formation of the Earth?&#xA;I have heard from sources that a big giant star exploded and the Earth was formed. Is this true ?&lt;/p&gt;&#xA;" OwnerUserId="2524" LastEditorDisplayName="user889" LastEditDate="2015-02-03T08:45:47.370" LastActivityDate="2022-05-26T19:32:49.783" Title="How was the Earth formed?" Tags="|earth-history|earth-system|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4363" PostTypeId="2" ParentId="4362" CreationDate="2015-02-03T09:11:56.330" Score="5" Body="&lt;p&gt;The following quote from &lt;a href=&quot;http://geology.about.com/od/nutshells/a/aa_earthbirth.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Birth of the Earth&lt;/a&gt; explains the current theory/model for the formation of the Solar System:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Long, long ago (some 5 billion years ago) in a perfectly ordinary place in the galaxy, a supernova exploded, pushing a lot of its heavy-element wreckage into a nearby cloud of hydrogen gas and interstellar dust. The mixture grew hot and compressed under its own gravity, and at its center a new star began to form. Around it swirled a disk of the same material, which grew white-hot from the great compressive forces. That new star became our Sun, and the glowing disk gave rise to Earth and its sister planets. We can see just this sort of thing happening elsewhere in the universe.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Read this article from Wikipedia as well.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Formation_and_evolution_of_the_Solar_System#Formation_of_planets&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Formation_and_evolution_of_the_Solar_System#Formation_of_planets&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="6467" LastEditDate="2022-05-17T14:31:50.220" LastActivityDate="2022-05-17T14:31:50.220" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="4364" PostTypeId="1" CreationDate="2015-02-03T09:42:52.343" Score="6" ViewCount="200" Body="&lt;p&gt;I'm studying the physics of the atmosphere but I'm struggling with the matter of viscosity (Navier-Stokes equation) for gravito-acoustic waves. From Landau-Lifschitz :&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;(T)_{ij} = -p\delta_{ij} + \eta(\partial_j\mathbf{v}_i + \partial_i\mathbf{v}_{j} - \frac{2}{3}\delta_{ij}\nabla\cdot\mathbf{v}) + \zeta\delta_{ij}\nabla\cdot\mathbf{v}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\eta$ is the dynamic viscosity, $\zeta$ is the second viscosity, $\mathbf{v}$ is the velocity, $p$ is the pressure, and $\delta$ the Kronecker delta.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is, in a windy viscous stratified atmosphere (up to 500km) how should I treat the viscous stress tensor $T$? Should I take into account both the dynamic viscosity (normal viscosity) and the second viscosity? Can I consider the viscosity coefficients $\eta, \zeta$ to be constant? What about the Stokes assumption $\nabla \cdot \mathbf{v} = 0$?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Considering viscosity can I still use the adiabatic assumption to settle the Navier-Stokes equation?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More specifically, for gravito-acoustic propagation should I consider shear effects as well ?&lt;/p&gt;&#xA;" OwnerUserId="2525" LastEditorUserId="192" LastEditDate="2015-02-03T16:51:26.237" LastActivityDate="2015-02-03T16:51:26.237" Title="Bulk and dynamic viscosity in the atmosphere" Tags="|meteorology|atmosphere-modelling|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4365" PostTypeId="2" ParentId="21" CreationDate="2015-02-03T23:29:39.067" Score="8" Body="&lt;p&gt;Coastal trapped Kelvin waves are important processes contributing to variability in the sea surface height and temperature near the coast. Field studies have measured large temperature fluctuations mainly made up of low-frequency internal Kelvin waves mostly of semi-diurnal tidal period at the continental shelf on the great barrier reef (&lt;a href=&quot;http://www.publish.csiro.au/paper/MF9830065&quot;&gt;Wolanski, 1983&lt;/a&gt;). Because they are balanced by Coriolis, in the Northern Hemisphere they remain fairly stable if they are propagating towards the North if the coast is on the right, or to the South if the coast is to the left. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;My question is this: are Kelvin waves important in determining the surface temperature variations of regions that are, for example, on the west side of mountain slopes like the Andes or Rockies?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It is pretty clear that Kelvin waves and associated upwelling play a crucial role in introducing nutrients, larvae and other components into the ocean's coastal regions (relatively cold water). However, the connection between surface temperature variation in the coastal waters and the temperature in the regions west of mountain ranges you mention is not so clear. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing that could happen is that, because upwelling is associated with relatively cool water being introduced to the near shore from the deep abyss, the coastal marine layer will have a lot of moisture. As the moisture laden air traverses a coastal mountain range, it will rise due to orographic lift and cool adiabatically, thereby raising relative humidity all the way to 100% resulting in rain. So the coastal side is cool and wet, whereas on the other side of the coastal range it will be much warmer and drier.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Wolanski, E., and G. L. Pickard. &quot;&lt;a href=&quot;http://www.publish.csiro.au/paper/MF9830065&quot;&gt;Upwelling by internal tides and Kelvin waves at the continental shelf break on the Great Barrier Reef.&lt;/a&gt;&quot; Marine and Freshwater Research 34.1 (1983): 65-80.&lt;/p&gt;&#xA;" OwnerUserId="200" LastActivityDate="2015-02-03T23:29:39.067" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4366" PostTypeId="1" AcceptedAnswerId="4367" CreationDate="2015-02-04T01:29:37.773" Score="16" ViewCount="2103" Body="&lt;p&gt;I found some blue patches in the Arabian desert in Google Earth.  It looks like as if they were lakes with sand dunes rising out of the water.  But there isn't water in the desert, at least not this much, or is there?  So what do we see on the image?  I realize that the colour we see in the image may not be accurate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dzjN2.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dzjN2.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.google.com/maps/@20.641166,54.3972003,23537m/data=!3m1!1e3&quot; rel=&quot;noreferrer&quot;&gt;Link to Google Maps&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;In response to Fred's comment about whether it might show water after a rain&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I took some time to browse &lt;a href=&quot;http://landsatlook.usgs.gov/&quot; rel=&quot;noreferrer&quot;&gt;Landsat archives&lt;/a&gt; and see if things are changing.  Here's a comparison of the same region on two different days (note the different dates, about 1.5 months apart).  The comparison shows that things are changing, i.e. it doesn't permanently look like this.  Most of the time it's like the first image.  This is not the exact same area as above, but it's &quot;nearby&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/TJ35K.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/EjJCJ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Are there satellite images freely available taken at wavelengths that can clearly show water?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Update 2&lt;/strong&gt;  Here's some &lt;a href=&quot;http://1.usa.gov/1DvKjT4&quot; rel=&quot;noreferrer&quot;&gt;daily MODIS images&lt;/a&gt; from the same time as the two photos above, I'm not really sure what to make of them though.  See the clouds passing through 2013 Aug 3-4.  The precipitation layers in the same tool do confirm rain during those two days.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Update 3&lt;/strong&gt;  &lt;a href=&quot;http://www.nasa.gov/multimedia/imagegallery/image_feature_1200.html&quot; rel=&quot;noreferrer&quot;&gt;Yet another image showing more clearly what looks like lakes.&lt;/a&gt;  Click for description and full-size image showing larger area.  This is the eastern part of &lt;em&gt;Rub' al Khali&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nasa.gov/multimedia/imagegallery/image_feature_1200.html&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WWvjg.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Update 4&lt;/strong&gt;  These are likely old and dried up lake beds.  &lt;a href=&quot;https://en.wikipedia.org/wiki/Rub%27_al_Khali#Lake_beds&quot; rel=&quot;noreferrer&quot;&gt;Mention on Wikipedia.&lt;/a&gt;  Quote from &lt;a href=&quot;https://www.saudiaramcoworld.com/issue/198903/lakes.of.the.rub.al-khali.htm&quot; rel=&quot;noreferrer&quot;&gt;article&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;All that remains of the lakes are their eroded basins, standing up in forlorn little buttes a meter or so high, &lt;strong&gt;in stark white or gray against the Rub' al-Khali's infinity of rusty-red sand&lt;/strong&gt;. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It doesn't explain the bluish colour, but it's likely these dried up lake beds that I see on the images.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sidetracked.com/the-empty-quarter/&quot; rel=&quot;noreferrer&quot;&gt;Some ground-level photos here.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2522" LastEditorUserId="6298" LastEditorDisplayName="user12525" LastEditDate="2022-02-06T17:30:57.960" LastActivityDate="2022-02-06T17:30:57.960" Title="What are these lake-like blue patches in the desert, visible in satellite image?" Tags="|geomorphology|desert|satellite-oddities|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4367" PostTypeId="2" ParentId="4366" CreationDate="2015-02-04T09:19:59.187" Score="18" Body="&lt;p&gt;The 'bluish' areas are exposed gypsum and gravel across which the sand dunes are moving. The colour is likely an artifact of the 'natural' colour palette used when processing the SPOT image. To understand just how arbitrary and variable the results of that processing can be, consider the following image captured at a fairly high zoom level in one of your 'blue' areas:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/eNwKw.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meanwhile just to the south-west, there is at least one identifiable lake (at 20.896022N ,54.007201E, perhaps an up-welling of ground water, possibly transient and apparently highly saline, judging from the lack of vegetation around it) and, as you can see here....&lt;img src=&quot;https://i.stack.imgur.com/dE80q.jpg&quot; alt=&quot;enter image description here&quot;&gt; it has an entirely different appearance to the blueish areas you've identified.&lt;/p&gt;&#xA;" OwnerUserId="2532" LastActivityDate="2015-02-04T09:19:59.187" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4368" PostTypeId="1" CreationDate="2015-02-04T14:45:30.083" Score="25" ViewCount="1256" Body="&lt;h2&gt;The problem&lt;/h2&gt;&#xA;&lt;p&gt;I am trying to figure out how &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; concentration trends are computed in the data provided by the Earth Systems Research Laboratory Mauna Loa Observatory. The data contains monthly measurements, seasonally corrected trend, and interpolated data with filled gaps. The trend and interpolated data should be computable from the raw averages. I was trying to reproduce the results of computing the trend and interpolation, but my values keep being slightly off.&lt;/p&gt;&#xA;&lt;p&gt;I have tried two formulas to compute the&#xA;trend that I call &lt;em&gt;formula1&lt;/em&gt; and &lt;em&gt;formula2&lt;/em&gt; below and neither reproduces the data exactly, though formula2 seems to fit pretty well.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/YVNu9.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;h2&gt;The data&lt;/h2&gt;&#xA;&lt;p&gt;The data &lt;a href=&quot;http://www.esrl.noaa.gov/gmd/ccgg/trends/&quot; rel=&quot;nofollow noreferrer&quot;&gt;(esrl.noaa.gov)&lt;/a&gt; is made available as a text file structured as follows:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;#  (-99.99 missing data;  -1 no data for #daily means in month)&#xA;#&#xA;#            decimal     average   interpolated    trend    #days&#xA;#             date                             (season corr)&#xA;1958   3    1958.208      315.71      315.71      314.62     -1&#xA;1958   4    1958.292      317.45      317.45      315.29     -1&#xA;1958   5    1958.375      317.50      317.50      314.71     -1&#xA;1958   6    1958.458      -99.99      317.10      314.85     -1&#xA;   . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Here &lt;em&gt;average&lt;/em&gt; is the average from monthly measurements of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; concentration in ppm units, &lt;em&gt;#days&lt;/em&gt; is the number of valid days' measurements per month if available.&lt;/p&gt;&#xA;&lt;p&gt;The other two columns, &lt;em&gt;interpolated&lt;/em&gt; and &lt;em&gt;trend&lt;/em&gt; are a bit more involved. The file describes the method to compute the values as follows.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The &amp;quot;interpolated&amp;quot; column includes average values from the preceding column&#xA;and interpolated values where data are missing.  Interpolated values are&#xA;computed in two steps.  &lt;strong&gt;First&lt;/strong&gt;, we compute for each month the average seasonal&#xA;cycle in a 7-year window around each monthly value.  In this way the seasonal&#xA;cycle is allowed to change slowly over time.  We then determine the &amp;quot;trend&amp;quot;&#xA;value for each month by removing the seasonal cycle; this result is shown in&#xA;the &amp;quot;trend&amp;quot; column.  Trend values are linearly interpolated for missing months.&#xA;The interpolated monthly mean is then the sum of the average seasonal cycle&#xA;value and the trend value for the missing month.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;h2&gt;The formulas&lt;/h2&gt;&#xA;&lt;p&gt;In order to avoid dealing with boundary effects I compare the results past the first 3.5 years of record, so that centered 7-year windows can be correctly defined. That is starting from September 1961.&lt;/p&gt;&#xA;&lt;p&gt;Let &lt;span class=&quot;math-container&quot;&gt;$x_t, t=1..N$&lt;/span&gt; be the monthly average values.&lt;/p&gt;&#xA;&lt;p&gt;I need to first compute &amp;quot;&lt;em&gt;the average seasonal&#xA;cycle in a 7-year window around each monthly value&lt;/em&gt;&amp;quot;. And then substract it from the data to obtain the trend.&lt;/p&gt;&#xA;&lt;p&gt;As I understand the average seasonal cycle is the difference between the seasonal filter and some seasonal average.&lt;/p&gt;&#xA;&lt;p&gt;To compute the 7-year seasonal filter for each &lt;span class=&quot;math-container&quot;&gt;$t \geq 3*12 + 6$&lt;/span&gt; I compute &lt;span class=&quot;math-container&quot;&gt;$s_t = \frac{1}{7}\Sigma_{j=-3}^{j=3}x_{t+12j}$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Now for a seasonal average I tried two options.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The 7-year seasonal filter average&#xA;&lt;span class=&quot;math-container&quot;&gt;$f_t=\frac{1}{12}\Sigma_{j=0}^{j=11}s_{t+j}$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;The 7-year average &lt;span class=&quot;math-container&quot;&gt;$a_t=\frac{1}{84}\Sigma_{j=-42}^{j=41}x_{t+j}$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Thereby &lt;em&gt;formula1&lt;/em&gt; is &lt;span class=&quot;math-container&quot;&gt;$x_t-(s_t-f_t)$&lt;/span&gt; and &lt;em&gt;formula2&lt;/em&gt; is &lt;span class=&quot;math-container&quot;&gt;$x_t-(s_t-a_t)$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;h2&gt;Conclusion&lt;/h2&gt;&#xA;&lt;p&gt;It seems to me that I misunderstand what is meant by &amp;quot;&lt;em&gt;the average seasonal&#xA;cycle in a 7-year window around each monthly value&lt;/em&gt;&amp;quot;. Neither &lt;span class=&quot;math-container&quot;&gt;$(s_t-f_t)$&lt;/span&gt;, nor &lt;span class=&quot;math-container&quot;&gt;$(s_t-a_t)$&lt;/span&gt; defined above fit. What is the correct formula?&lt;/p&gt;&#xA;&lt;p&gt;I have put the data into a read-only (&lt;a href=&quot;https://docs.google.com/spreadsheets/d/1D1ndBLGDfF5t65754HiXE_bVtgNwR1GDvwOFOCJ7J2A/edit?usp=sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google sheet&lt;/a&gt;) for a quick check.&lt;/p&gt;&#xA;" OwnerUserId="2511" LastEditorUserId="6031" LastEditorDisplayName="user889" LastEditDate="2021-06-06T09:44:30.250" LastActivityDate="2021-10-24T11:33:50.787" Title="How are Mauna Loa $\ce{CO2}$ monthly trends computed?" Tags="|atmosphere|geochemistry|volcanology|co2|statistics|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="4369" PostTypeId="1" CreationDate="2015-02-04T19:52:14.293" Score="18" ViewCount="2259" Body="&lt;p&gt;The relation between shear wave velocity (V&lt;sub&gt;s&lt;/sub&gt;) and pressure wave velocity (V&lt;sub&gt;p&lt;/sub&gt;) is often expressed as V&lt;sub&gt;p&lt;/sub&gt;/V&lt;sub&gt;s&lt;/sub&gt;. Wouldn't the opposite be more logic? V&lt;sub&gt;s&lt;/sub&gt;/V&lt;sub&gt;p&lt;/sub&gt; would never lead to division with zero and the relation would always be a neat number between 0 and 1. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the reasons behind this convention?&lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="192" LastEditDate="2015-02-04T21:33:42.447" LastActivityDate="2015-02-05T15:28:50.710" Title="Why Vp/Vs and not Vs/Vp?" Tags="|geophysics|seismology|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4370" PostTypeId="2" ParentId="4369" CreationDate="2015-02-05T02:07:22.283" Score="5" Body="&lt;p&gt;Possibly because Vp is more sensitive to fluids in the pore space than Vs so that Vp/Vs increases as the bulk modulus of the fluid in the pore space increases.&lt;/p&gt;&#xA;" OwnerUserId="2538" LastActivityDate="2015-02-05T02:07:22.283" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4371" PostTypeId="1" CreationDate="2015-02-05T06:59:53.493" Score="13" ViewCount="245" Body="&lt;p&gt;Natural habitats have a &quot;critical load&quot; threshold in regards to deposition of nitrogen compounds (both wet and dry deposition).  The critical load is calculated in kg N / hectare and is specific to local ecoregion type.  I've heard that critical loads are based on lichens or other simple vegetation, but I'm not sure.  How are critical loads calculated?  What are the factors that are considered?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An example of critical loads are shown below for the western USA. In general the ecoregions are pretty coarse and in my mind over-generalized.  I'm curious about how these ecoregion distinctions are made.  How many types of ecoregions are there and what are they based on?Is it based on the vegetation that currently exists in that area (which can sometimes be distinctly different than indigenous vegetation)?  Or is it based on some historical vegetation type?  Furthermore, what is the expected result if deposition surpasses the critical load and what is the time horizon involved? &lt;img src=&quot;https://i.stack.imgur.com/B6obK.png&quot; alt=&quot;Critical Load by Eco-Region&quot;&gt;!&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2015-02-05T16:13:42.000" LastActivityDate="2015-08-22T02:44:48.733" Title="How are critical loads of nitrogen deposition on eco-regions determined?" Tags="|nitrogen|acid-rain|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4372" PostTypeId="2" ParentId="4369" CreationDate="2015-02-05T14:58:31.133" Score="14" Body="&lt;p&gt;After &lt;a href=&quot;https://twitter.com/kwinkunks/status/563144236988907521&quot; rel=&quot;noreferrer&quot;&gt;quite a bit of conversation on Twitter&lt;/a&gt;, I think it's arbitrary. Tradition is probably the prevailing reason.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It would be interesting to go back through the literature to see who first used it. My hunch is that it goes back to &lt;a href=&quot;http://subsurfwiki.org/wiki/Zoeppritz_equations&quot; rel=&quot;noreferrer&quot;&gt;the Zoeppritz equations&lt;/a&gt; (Zoeppritz 1919), which feature both $V_\text{S}/V_\text{P}$ and $V_\text{P}/V_\text{S}$. I bet Aki &amp;amp; Richards (1980) also had something to do with its propagation, at least in the exploration geophysics community. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thinking about it, I think there are some good reasons to use $V_\text{S}/V_\text{P}$ instead of $V_\text{P}/V_\text{S}$.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;It's well-behaved&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;As the OP said, $V_\text{S}/V_\text{P}$ behaves nicely, being constrained in the range [0,1) for rocks and fluids (and weird things like bitumen) — compared to $V_\text{P}/V_\text{S}$, which varies in the range 1 to infinity/undefined. I suppose you could call that 'neat'...&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;It's a good gas indicator&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;If you have a background of brine (say) and want to see gas anomalies, then my insufficient research suggests that $V_\text{S}/V_\text{P}$ is actually a better discriminator:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/SBqwj.png&quot; alt=&quot;A table showing some Vp/Vs ratios for gas- and water-wet rocks.&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;It's in the Aki–Richards equation&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;This is the formulation from Avseth et al. (2006):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ R(\theta) = \frac{1}{2} \frac{\Delta \rho}{\rho} - 2 \left( \! \frac{V_\mathrm{S}}{V_\mathrm{P1}} \! \right)^2 \frac{\Delta \rho}{\rho} \sin^2 \theta + \frac{1}{2} \frac{\Delta V^2_\mathrm{P}}{V^2_\mathrm{P}} \frac{1}{\cos^2 \theta_\mathrm{avg}} - 4 \left( \! \frac{V_\mathrm{S}}{V_\mathrm{P1}} \! \right)^2 \frac{\Delta V^2_\mathrm{S}}{V^2_\mathrm{S}} \sin^2 \theta $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Refer to the book or &lt;a href=&quot;http://subsurfwiki.org/wiki/Aki-Richards_equation&quot; rel=&quot;noreferrer&quot;&gt;SubSurfWiki&lt;/a&gt; for the symbol definitions etc. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hmm, none of these are reasons why $V_\text{P}/V_\text{S}$ prevails. This is starting to look like the $\pi$ vs $\tau$ debate...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Aki, K, and PG Richards (1980). &lt;em&gt;Quantitative Seismology: Theory and Methods.&lt;/em&gt; WH Freeman and Co.&lt;/li&gt;&#xA;&lt;li&gt;Avseth, P, T Mukerji, G Mavko (2006). &lt;em&gt;Quantitative Seismic Interpretation&lt;/em&gt;. Cambridge University Press.&lt;/li&gt;&#xA;&lt;li&gt;Castagna, J, and H Swan (1997). Principles of AVO crossplotting. &lt;em&gt;The Leading Edge&lt;/em&gt;, Society of Exploration Geophysicists, 17, 337–342. &lt;/li&gt;&#xA;&lt;li&gt;Smith, T, et al (2003). Gassmann fluid substitutions; a tutorial. &lt;em&gt;Geophysics&lt;/em&gt; (April 2003), 68(2):430-440. &lt;a href=&quot;http://dx.doi.org/10.1190/1.1567211&quot; rel=&quot;noreferrer&quot;&gt;DOI 10.1190/1.1567211&lt;/a&gt;. &lt;/li&gt;&#xA;&lt;li&gt;Zoeppritz, KB (1919). Erdbebenwellen VII. VIIb. Über Reflexion und Durchgang seismischer Wellen durch Unstetigkeitsflächen. Nachrichten von der Königlichen Gesellschaft der Wissenschaften zu Göttingen, Mathematisch-physikalische Klasse, 66-84.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2015-02-05T15:28:50.710" LastActivityDate="2015-02-05T15:28:50.710" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4374" PostTypeId="1" CreationDate="2015-02-06T03:53:23.790" Score="15" ViewCount="1000" Body="&lt;p&gt;I noticed these detailed tree-like river structures in Google Earth&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2NUtk.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2NUtk.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.com/maps/@30.1207655,48.7767907,5751m/data=!3m1!1e3&quot; rel=&quot;noreferrer&quot;&gt;Google Maps link&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How and why do these form?  Rivers don't typically split.  What would cause the water to keep branching off again and again, forming these tree-like fractal patterns?  I count as many as 7-8 branch splits even in the smaller trees.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I expect the answers will provide qualitative explanations, but if anyone can connect it to quantitative physical models that would be even better (e.g. diffusion limited aggregation, viscous fingering, dielectric breakdown all have analogous mechanisms behind them; could this one be related?)&lt;/p&gt;&#xA;" OwnerUserId="2522" LastEditorUserId="10681" LastEditDate="2018-09-16T03:13:33.770" LastActivityDate="2018-09-16T03:13:33.770" Title="How and why do these tree-like river structures form?" Tags="|hydrology|rivers|geomorphology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4375" PostTypeId="1" AcceptedAnswerId="4376" CreationDate="2015-02-06T04:07:16.477" Score="9" ViewCount="673" Body="&lt;p&gt;I recently visited a place called Talakad/Talakadu about 40 km from Mysore, India. Its an amazing place where a whole city has been covered by sand about 15 m deep. The local myth is that a curse turned the once thriving town to a barren dune. Does anyone have any scientific explanations?&lt;/p&gt;&#xA;" OwnerUserId="2544" LastEditorUserId="725" LastEditDate="2015-02-13T05:10:06.727" LastActivityDate="2015-02-13T05:10:06.727" Title="How did sand dunes appear in the midst of a fertile region?" Tags="|geomorphology|erosion|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4376" PostTypeId="2" ParentId="4375" CreationDate="2015-02-06T05:39:21.947" Score="9" Body="&lt;p&gt;It appears the sands at Talakad are the result of a ecological disaster that occurred in the 17th Century. At the time, a dam was constructed north of Talakad on Kaveri River which caused the river to be diverted. This exposed a sand deposit in the river which was subsequently moved to Talakad by monsoonal winds. The following quote is from this source &lt;a href=&quot;http://www.researchgate.net/profile/Ashit_Roy/publication/264159940_The_mystic_sand_dune_covered_temples_of_Talakad_Mysore_District_Karnakata_Evidence_of_earthquake_related_destruction/links/53d07fea0cf25dc05cfe4592.pdf&quot; rel=&quot;noreferrer&quot;&gt;AB Roy &amp;amp; MS Sethumadhav, 2014&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It is thought to have originated due to an ‘eco-disaster’ that&#xA;  lashed the region during the 17th century. That was the&#xA;  time when the normal flow of the Kaveri River was&#xA;  impeded because of the construction of a dam on the up-&#xA;  stream side, north of Talakad and subsequent diversion of&#xA;  water in a different direction. As a result, the water level&#xA;  at the point bar on the concave side of the Kaveri meander southwest of Talakad was significantly lowered leading to the buildup of sand at this place. The accumulated&#xA;  sand was then actively reworked and carried by the&#xA;  northeasterly monsoon winds, which were subsequently&#xA;  deposited around Talakad engulfing the temples and other&#xA;  settlements in the region. The yellow coloured, uniformly fine-grained and homogeneous nature of the sand&#xA;  without any clay material in it provides further proof that&#xA;  the air-borne sand deposited as dunes&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2522" LastEditDate="2015-02-07T04:04:29.997" LastActivityDate="2015-02-07T04:04:29.997" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4377" PostTypeId="2" ParentId="4374" CreationDate="2015-02-06T06:26:02.590" Score="17" Body="&lt;p&gt;The river isn't splitting. The picture shows a number of &lt;a href=&quot;http://en.wikipedia.org/wiki/Drainage_system_%28geomorphology%29&quot;&gt;dendritic drainage&lt;/a&gt; channels flowing into a larger river/stream. They are the most common form of topographical draining system. They develop in gently sloping topography and they ...&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;develops in regions underlain by homogeneous material. That is, the subsurface geology has a similar resistance to weathering so there is no apparent control over the direction the tributaries take. Tributaries joining larger streams at acute angle (less than 90 degrees) &lt;a href=&quot;http://www.earthonlinemedia.com/ebooks/tpe_3e/fluvial_systems/drainage_patterns.html&quot;&gt;[Earth Drainage Systems]&lt;/a&gt;. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You'll notice in the picture all the drainage channels intersect the river at approximately 90 degrees. Also it appears the channels dendritic channels have formed in what looks like a sandy/silty sediment, again homogenous material.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other sources that may be helpful:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://link.springer.com/article/10.1007/BF01134037#page-1&quot;&gt;Experiment to Examine Dendritic River Systems&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.researchgate.net/publication/229645434_Simulations_of_flows_and_water_depth_in_a_dendritic_river_system&quot;&gt;Dendritic river flow simulations&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.researchgate.net/publication/229578245_FLOW_DIRECTION_AND_BRANCHING_GEOMETRY_AT_JUNCTIONS_IN_DENDRITIC_RIVER_NETWORKS*&quot;&gt;Flow direction &amp;amp; branching geometry&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://journal.frontiersin.org/Journal/10.3389/fphy.2014.00009/full&quot;&gt;Dendritic Design&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2015-02-06T06:31:33.100" LastActivityDate="2015-02-06T06:31:33.100" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4378" PostTypeId="1" AcceptedAnswerId="4382" CreationDate="2015-02-06T09:06:25.713" Score="9" ViewCount="1014" Body="&lt;p&gt;What effect does Earth's size have on the temperature of the north and south poles? If the Earth were larger, or smaller, would this affect those temperatures?&lt;/p&gt;&#xA;" OwnerUserId="2546" LastActivityDate="2015-02-08T14:54:41.413" Title="Does earth's size affect the temperature of the poles?" Tags="|temperature|poles|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4380" PostTypeId="1" CreationDate="2015-02-06T15:57:07.923" Score="8" ViewCount="2865" Body="&lt;p&gt;I am not really a &quot;budding seismologist.&quot; I am a chemistry/physics teacher teaching an Earth science class (low academic level) in a small-town high school. (My college coursework in earth sciences = 0) I understand the concept of triangulation to determine an earthquake's origin, and I realize there are some subtleties in wave analysis such as pP and sP waves. What I don't understand is how the triangulation determines the epicenter instead  of the focus. Wouldn't the S-P lag times for 3 stations give an intersection point at the focus since that is the actual point of origin for the waves?&lt;/p&gt;&#xA;" OwnerUserId="2550" LastEditorDisplayName="user889" LastEditDate="2015-02-14T11:38:16.347" LastActivityDate="2015-02-16T17:24:40.453" Title="Distance to epicenter vs distance to focus" Tags="|geophysics|seismology|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4381" PostTypeId="2" ParentId="4380" CreationDate="2015-02-06T22:31:02.960" Score="1" Body="&lt;p&gt;This is a good question, but it really has a simple answer. How can you determine the depth of an object when you are not even calculating it? Triangulation uses circles, 2-D shapes, so when finding the solution to the equations of circles that solve all 3 circles, you only find X and Y. Z isn't even being solved for.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Triangulation is not precise. In practice, we end up using much more than 3 stations and statistical methods to find the precise epicenter (and other methods to find the focus). &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="32" LastEditDate="2015-02-06T22:51:47.397" LastActivityDate="2015-02-06T22:51:47.397" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4382" PostTypeId="2" ParentId="4378" CreationDate="2015-02-06T23:54:11.880" Score="4" Body="&lt;p&gt;The primary factor determining the temperature of a planet is the radiation it receives from its sun.  If this were the only factor, it would be possible to estimate its temperature using the black body radiation law, as described e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Black-body_radiation#Temperature_relation_between_a_planet_and_its_star&quot; rel=&quot;nofollow&quot;&gt;on Wikipedia&lt;/a&gt;.  &lt;em&gt;Based on this calculation, the size of the planet has no effect on its temperature.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, there are other factors contributing to the temperature of the planet, such as its atmosphere (greenhouse effect), internal heating due to radioactive decay, and the surface reflectivity, affected by such things as plant or snow cover, etc.  All these can and &lt;a href=&quot;https://en.wikipedia.org/wiki/Geologic_temperature_record&quot; rel=&quot;nofollow&quot;&gt;have&lt;/a&gt; changed in the past.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Black-body_radiation#Temperature_of_Earth&quot; rel=&quot;nofollow&quot;&gt;The black-body approximation gives a temperature of about -18 C&lt;/a&gt;, thus the other factors have a smaller but still significant contribution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the question is how are the other factors affected by the size of the planet?&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Effect of the atmosphere: I cannot comment.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Internal heating: the heat generated by radioactive decay is proportional to the amount of radioactive material, i.e. the volume of the Earth (proportional to its radius $R$ cubed, $\sim R^3$), assuming a fixed density and composition.  The heat loss is proportional to the surface area ($\sim R^2$).  &lt;em&gt;So the larger the planet, the higher the temperature increase coming from internal heating.&lt;/em&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="2522" LastEditorUserId="192" LastEditDate="2015-02-08T14:54:41.413" LastActivityDate="2015-02-08T14:54:41.413" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4383" PostTypeId="2" ParentId="4341" CreationDate="2015-02-07T00:58:47.863" Score="5" Body="&lt;p&gt;Looking at the 2nd image in your question, namely of the vertical profile, the feature inhabits what appears to be an erosion channel to the valley floor (a very rough estimate of the erosion channel is shown below).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/p7TMk.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;em&gt;Please excuse the rough-MS Paint style arrow&lt;/em&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The feature has the appearance of being an example of a small slope failure, a similar, but much smaller example of other much larger landslides have been observed in the Valles Marineris according to the article &lt;a href=&quot;http://geology.gsapubs.org/content/early/2015/01/05/G36215.1&quot; rel=&quot;noreferrer&quot;&gt;Long-runout landslides and the long-lasting effects of early water activity on Mars&lt;/a&gt; (Watkins et al. 2014).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to research based on observations of similar larger scale features, the article &lt;a href=&quot;http://www.raschultzunr.net/pdf%20reprints/NeufferRAS-VM06.pdf&quot; rel=&quot;noreferrer&quot;&gt;Mechanisms of slope failure in Valles Marineris, Mars&lt;/a&gt; (Neuffer and Schultz, 2006) slope failures on Mars have been found to occur due to gravitational, fluid or seismic (i.e. 'marsquakes') influences.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other influence as to why these landslides occur in the area is explained by Watkins et al. (2014) from observations and models based on spectral imaging and satellite image analyses, a significant amount of hydrated silicate clays contained within the stratigraphy of the Valles Marineris facilitate geomorphic processes, including landslides - the process is aptly used as the title of the Red Planet Report web-article &lt;a href=&quot;http://redplanet.asu.edu/?p=11270&quot; rel=&quot;noreferrer&quot;&gt;Clays greased long landslides in Valles Marineris&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-02-07T01:25:24.490" LastActivityDate="2015-02-07T01:25:24.490" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4384" PostTypeId="1" CreationDate="2015-02-07T02:31:36.770" Score="12" ViewCount="805" Body="&lt;p&gt;Some estimates claim that currently about one third of current human annual emissions of $\ce{CO2}$ are absorbed by the oceans. &lt;a href=&quot;http://dx.doi.org/10.5670/oceanog.2012.71&quot; rel=&quot;noreferrer&quot;&gt;Some authors&lt;/a&gt; have calculated that about half of the global ocean total absorption occurs in the Southern Ocean. They also claim that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the ocean $\ce{CO2}$ sink intensity has been weakening for several decades and has changed from a net sink to a net source since 2005&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Considering the potential changes in ocean circulation and biological activity associated with climate change, can we expect the Southern Ocean to remain as such an important sink or are we moving toward a regime change that will lead to the ocean becoming a source of $\ce{CO2}$?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/UnkIf.jpg&quot; alt=&quot;Carbon cycle&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-12-21T03:15:58.610" Title="Will the Southern Ocean act as a net source or sink for atmospheric $\ce{CO2}$ in the future?" Tags="|ocean|oceanography|antarctic|co2|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4385" PostTypeId="1" AcceptedAnswerId="4406" CreationDate="2015-02-07T03:12:38.147" Score="8" ViewCount="371" Body="&lt;p&gt;Looking at WRF currently but I am sure this applies to most weather models there is a file (specifically &lt;code&gt;LANDUSE.TBL&lt;/code&gt;) that specifies USGS derived albedo, soil moisture and other parameters on a biannual basis - one for summer and one for winter. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why would not these parameters vary on a more seasonal basis and/or on a annual basis? Why are these these variables assumed to be constant? Would not changing vegetation or land cover modifications affect these values on a regional basis as well as their impact on regional climate? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also would it make sense to model these values on a regional basis after deriving them from remote sensing as indicated in the below mentioned article &lt;a href=&quot;http://web.maths.unsw.edu.au/~jasone/publications/evansetal2012a.pdf&quot; rel=&quot;nofollow&quot;&gt;http://web.maths.unsw.edu.au/~jasone/publications/evansetal2012a.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user889" LastEditDate="2015-02-11T20:08:21.560" LastActivityDate="2015-02-13T17:23:04.933" Title="The climatological variance of albedo, soil moisture in weather models" Tags="|atmosphere-modelling|climatology|mesoscale-meteorology|wrf|" AnswerCount="2" CommentCount="7" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4386" PostTypeId="2" ParentId="2739" CreationDate="2015-02-07T08:02:54.607" Score="5" Body="&lt;p&gt;You may also find localised geological guides, such as the Roadside Geology series.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://geology.com/store/roadside-geology.shtml&quot;&gt;http://geology.com/store/roadside-geology.shtml&lt;/a&gt; has a listing. While I have not used them, I have seen them crop up fairly often as a nice option when looking for interesting geology in more general terms, including for some outcrops.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(I would have made this a comment, rather than an answer, but have no rep yet.)&lt;/p&gt;&#xA;" OwnerUserId="2514" LastActivityDate="2015-02-07T08:02:54.607" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4387" PostTypeId="1" CreationDate="2015-02-07T16:24:40.913" Score="7" ViewCount="983" Body="&lt;p&gt;The Laacher See is a volcanic crater lake in Germany, with a diameter of 2 km (1.2 mi) in Rhineland-Palatinate area, approximately 24 km (15 mi) northwest of Koblenz and 37 km (23 mi) south of Bonn, and is closest to the town of Andernach situated 8 km (5.0 mi) to the east on the river Rhine. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the &lt;a href=&quot;http://www.volcanodiscovery.com/laacher_see.html&quot;&gt;Volcano Discovery&lt;/a&gt; web page about the volcano, it last erupted about 12.9 thousand years ago, in an eruption larger in size than Mt. St. Helens 1980 eruption.  It is believed to have erupted in a Plinian style.  The website classifies the volcanic system as dormant, with emissions of $\ce{CO2}$ and seismicity recorded in the area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the region of Germany that the Laacher See and the surrounding East Eifel mountains are not on a plate boundary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is the origin of the Laacher See caldera magma in Germany?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2015-02-07T16:24:40.913" Title="What is the origin of the Laacher See caldera magma in Germany?" Tags="|volcanology|geochemistry|volcanoes|intraplate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4388" PostTypeId="2" ParentId="4387" CreationDate="2015-02-07T16:24:40.913" Score="5" Body="&lt;p&gt;The East Eifel Volcanics, of which the Laacher See Caldera is a part of, is located on the Rhenish Shield and is associated with the Cenozoic Upper Rhine Graben continental rift zone (Aber, 2012). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ukrich and Gabrielle (2013) hypothesise that as the region did have and still has active tectonics, that the magma chamber for the Laacher See Caldera could have been the result of magma accumulating in voids opened up through regional strike-slip faulting (including the 'Laacher See Strike Slip' and Ochtending Fault), block rotation and regional uplift. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to Schmitt et al. (2010), the parental magmatic melt that formed the carbonatite-syenite suite based petrology that dominates the Laacher See caldera is derived from a mantle melt differentiated to phonolite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is believed that the magma resided/accumulated for around 20,000 years prior to the eruption.  Schmitt et al. hypothesise that the magma had a cooler and older outer edge, compositionally zoning to a hotter phonolitic core - the presence of younger phenocrysts could indicate a magma reorganisation just prior to the eruption.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Aber, 2012, &lt;a href=&quot;http://academic.emporia.edu/aberjame/tectonic/eifel/eifel.htm&quot; rel=&quot;noreferrer&quot;&gt;Volcanism of the Eifel, Germany Region&lt;/a&gt;, &lt;em&gt;GO 326 Plate Tectonics course notes&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Schmitt et al. 2010, &lt;a href=&quot;http://sims.ess.ucla.edu/akschmitt/Schmitt_etal_2010.pdf&quot; rel=&quot;noreferrer&quot;&gt;Magmatic Longevity of Laacher See Volcano (Eifel, Germany) Indicated by U-Th Dating of Intrusive Carbonatites&lt;/a&gt;, &lt;em&gt;Journal of Petrology&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ulrich and Gabrielle, 2013, &lt;a href=&quot;http://adsabs.harvard.edu/abs/2013EGUGA..15.5908S&quot; rel=&quot;noreferrer&quot;&gt;Why does the Size of the Laacher See Magma Chamber and its Caldera Size not go together? - New Findings with regard to Active Tectonics in the East Eifel Volcanic Field&lt;/a&gt;, &lt;em&gt;EGU General Assembly 2013&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2015-02-07T16:24:40.913" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4390" PostTypeId="1" CreationDate="2015-02-08T16:14:00.523" Score="11" ViewCount="263" Body="&lt;p&gt;It is common to prepare flow duration curves from a set of daily river flow data, but does it make sense to build a flow duration curve from a set of monthly &lt;strong&gt;&lt;em&gt;minimum&lt;/em&gt;&lt;/strong&gt; flow data? I searched on internet, but the key word &quot;minimum flow duration curve&quot; does not return any relevant document.&lt;/p&gt;&#xA;" OwnerUserId="2551" LastEditorUserId="10681" LastEditDate="2018-09-04T11:36:20.087" LastActivityDate="2018-09-04T11:36:20.087" Title="Minimum flow duration curves" Tags="|hydrology|rivers|statistics|data-analysis|" AnswerCount="1" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4391" PostTypeId="1" AcceptedAnswerId="4393" CreationDate="2015-02-09T09:22:36.703" Score="13" ViewCount="1961" Body="&lt;p&gt;The density of ice is 0.9167 g/cm&lt;sup&gt;3&lt;/sup&gt; at 0 °C (under atmospheric pressure).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know of two factors that may influence this (are there more?)&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Pressure&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://ak.water.usgs.gov/glaciology/FAQ.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;glaciology faq (&lt;em&gt;Common Questions and Myths about Glaciers&lt;/em&gt;)&lt;/a&gt; at the Alaska Science Center of the  U.S. Geological Survey (USGS) mentions for glacier depth:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A good guess is that the ice thickness is about one-half of the surface width of the glacier. Although few glaciers have been measured, the measured thicknesses range from a few tens of meters for small glaciers to about 1,500 meters for the largest glaciers in Alaska.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Does the density of ice change significantly with depth?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Ice&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Wikipedia article on ice&lt;/a&gt; mentions the density of ice increasing slightly with decreasing temperature, and the different &lt;a href=&quot;http://en.wikipedia.org/wiki/Ice#Phases&quot; rel=&quot;nofollow noreferrer&quot;&gt;phases&lt;/a&gt; of ice under pressure, but nothing on density.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Inclusion of air&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Googling for &lt;a href=&quot;https://www.google.com/search?q=pressure+ice+density&quot; rel=&quot;nofollow noreferrer&quot;&gt;pressure ice density&lt;/a&gt; the (my) first search finds &lt;a href=&quot;http://www.igsoc.org:8080/journal/3/27/igs_journal_vol03_issue027_pg568-573.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Density of glacier ice&lt;/a&gt; at the International Glaciological Society. This focuses on air in glaciers making the density &lt;em&gt;lower&lt;/em&gt;, and concludes that at larger depths we reach that 0.92 limit:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/QxaE6.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;What would be a good average to take?&lt;/p&gt;&#xA;" OwnerUserId="595" LastEditorUserId="20" LastEditDate="2015-02-17T04:30:58.963" LastActivityDate="2015-02-17T04:30:58.963" Title="Converting glacier volume to mass: what ice density to use?" Tags="|glaciology|glacier|ice|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4392" PostTypeId="2" ParentId="2739" CreationDate="2015-02-09T13:21:20.743" Score="3" Body="&lt;p&gt;&lt;a href=&quot;http://macrostrat.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Macrostrat&lt;/a&gt; is (or in fact will be) what you are looking for I think.&lt;br&gt;&#xA;This database is still in development and is apparently only available through the website as a beta so far. It only seems to cover the US, Australia and New Zealand to this date but you can &lt;a href=&quot;http://macrostrat.org/search_form.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;search&lt;/a&gt; for specific formations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From your example, here is a screenshot of the result I had while looking for surface outcrops of halite:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/SP93h.png&quot; alt=&quot;US halite&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;or when looking for the Salina Group (the blue dots are cross-reference from the Paleobiology Database, if I understood correctly):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/xHQlL.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As they say on the front page, so far, the functionalities are very limited.&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2015-02-09T13:29:14.510" LastActivityDate="2015-02-09T13:29:14.510" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4393" PostTypeId="2" ParentId="4391" CreationDate="2015-02-09T14:27:26.717" Score="12" Body="&lt;p&gt;This is a non-trivial issue. When you look at volume change of a glacier, you typically subtract two digital elevation models to obtain the difference between the two. First, you must differentiate between ice sheets where ice berg calving reduces volume and more ordinary glaciers with melt processes. There are of course calving glaciers as well so it is possible to get into great detail for any one specific glacier, so here I will just discuss the most common case which is a smaller glacier with melt-freeze conditions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The change in elevation differs in magnitude across the glacier surface due to the movement of the glacier and accumulation-melt processes. The surface material can be (1) glacier ice, (2) snow, (3) firn snow that has survived a melt season) or (4) super imposed ice all with more or less differing densities, you need to assess what sort of material has been removed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ice can be approximated by a density of 900 kg/m&lt;sup&gt;3&lt;/sup&gt;, firn has a density of about 600 kg/m&lt;sup&gt;3&lt;/sup&gt; but it must be remembered that the firn is converted to glacier ice by metamorphic processes so that the density changes with depth from 600 to 900 kg/m&lt;sup&gt;3&lt;/sup&gt;. the transition to ice occurs at depths of about 30 m in temperate glaciers although few studies exist on the actual processes that occur. Snow have very differing densities but considering averages, I would say that it would vary between 350 to maybe 500 kg/m&lt;sup&gt;3&lt;/sup&gt; for winter (cold) conditions and around 550 kg/m&lt;sup&gt;3&lt;/sup&gt; for a melting snow pack. Super-imposed ice is closer to ice and probably varies in the upper range of 800--900 kg/m&lt;sup&gt;3&lt;/sup&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To make matters worse, snow superimposes firn which in turn superimposes ice. This means that in the accumulation area, volume change can result from both a reduction in a snow cover and the firn layer. In the zone near the equilibrium line there can be a loss of both firn and ice. this is also where the superimposed ice will play a role.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So there is no simple density to use since the loss you try to estimate will involve varying types of densities spatially as well as vertically. For annual changes, you can largely ignore the vertical distribution, but with volume changes covering larger periods where climate change influences the longer term location of the equilibrium line and the size of the accumulation area, vertical layering also has to be included.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a first approximation, a surface zonation of ice snow and possibly firn can be used and perhaps lumping snow and firn with a single density of around 600 kg/m&lt;sup&gt;3&lt;/sup&gt; can be used. I would, however, say that to some extent any choice you make will be wrong, so being aware of complexity and the limitations is the only way forward.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A couple of useful sources relating to the question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.the-cryosphere.net/7/877/2013/tc-7-877-2013.html&quot; rel=&quot;nofollow&quot;&gt;Huss, M., 2013. Density assumptions for converting geodetic glacier volume change to mass change. &lt;em&gt;The Cryosphere&lt;/em&gt; [Open Access] &lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.the-cryosphere-discuss.net/7/C148/2013/tcd-7-C148-2013.pdf&quot; rel=&quot;nofollow&quot;&gt;Moholdt, G., (Referee) Interactive comment on “Density assumptions for converting geodetic glacier volume change to mass change” by M. Huss. The Crypshere Discuss. [Open Access]&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="81" LastEditDate="2015-02-12T12:28:04.610" LastActivityDate="2015-02-12T12:28:04.610" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4394" PostTypeId="2" ParentId="1048" CreationDate="2015-02-10T19:48:42.053" Score="-1" Body="&lt;p&gt;stone is an engineering term - so applicable to gravel, hardcore for roads etc etc. Doesn't matter at all what its made of.&lt;/p&gt;&#xA;" OwnerUserId="2560" LastActivityDate="2015-02-10T19:48:42.053" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4395" PostTypeId="1" CreationDate="2015-02-10T21:40:01.583" Score="12" ViewCount="1026" Body="&lt;p&gt;Recently, I took the following picture:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/ecruU.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have read about this phenomenon and I think it is caused by water vapour that is pressed out of the ground and then freezes due to low temperature. However, I cannot recall the name of this phenomenon and I couldn't find it on the internet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The picture was taken in the Alps around 3000 meters above sea level in August. I'm pretty sure that the white thing is ice. They're a couple of centimetres long and quite porous. I found them on top of an earthy and slaty flank of a mountain early in the morning (around 8 am).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is this phenomenon called?&lt;/p&gt;&#xA;" OwnerUserId="2561" LastEditorUserId="36" LastEditDate="2015-02-11T15:33:37.500" LastActivityDate="2015-02-11T15:33:37.500" Title="Is there a name for this type of ice crystal?" Tags="|glaciology|ice|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4396" PostTypeId="2" ParentId="4395" CreationDate="2015-02-10T23:23:49.003" Score="12" Body="&lt;p&gt;This is &lt;em&gt;needle ice&lt;/em&gt; which forms when moist soil freezes, for example during a cold night. Freezing starts at the ground surface and as ice is formed moisture gradients develop which draws water to the freezing front and growth continues. Ideal conditions may be a sub-freezing night after a rainy day or a sub-freezing night after a day of snow melt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the &lt;a href=&quot;https://nsidc.org/cryosphere/frozenground/how_fg_affects_land.html&quot;&gt;National Snow and Ice Data Center (NSIDC)&lt;/a&gt; site needle ice be up to 40 cm in length. Since the favourable conditions are not unique to soils, although most often encountered in soils, needle ice can develop from freezing of, for example, vegetation&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2015-02-10T23:23:49.003" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4397" PostTypeId="2" ParentId="2410" CreationDate="2015-02-11T05:20:56.930" Score="-2" Body="&lt;p&gt;,&#xA;          I propose that the “snow ball Earth” was brought to a close by the dust from a huge meteorite (the largest known on Earth) impacting Australia (see &lt;a href=&quot;http://charles_w.tripod.com/antipode.html&quot; rel=&quot;nofollow&quot;&gt;http://charles_w.tripod.com/antipode.html&lt;/a&gt; ) settling onto the ice and melting it by a bare soil warming affect (see &lt;a href=&quot;http://charles_w.tripod.com/climate.html&quot; rel=&quot;nofollow&quot;&gt;http://charles_w.tripod.com/climate.html&lt;/a&gt; ) and thus initiating the Cambrian. The dust fertilizing the ocean probably contributed considerably to the explosion of life then. That initiation was probably considerably assisted by the subsequent release of methane gas from methane ice under the ocean floor and by dust from volcanic eruptions from the Bahamas Islands, which are located at the antipode (opposite side of a sphere) of the above impact. The close correlation of volcanoes on Mars with meteorite impacts at their antipodes gives supporting evidence for such a phenomenon. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;.&#xA;                    Sincerely,  Charles Weber&lt;/p&gt;&#xA;" OwnerUserId="2564" LastActivityDate="2015-02-11T05:20:56.930" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4398" PostTypeId="2" ParentId="3082" CreationDate="2015-02-11T09:41:47.483" Score="6" Body="&lt;p&gt;The first thing to note here is that the zircons you mention in your question are the only thing we have dating from the Hadean: no known Hadean continental or oceanic crust have been found to date. So, all informations come from these zircons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What do they tell us? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rare earth element (REE) composition of these zircons (and in particular the zoning of said REE inside the mineral) suggests that they formed in a magma derived from the melting of a continental crust (&lt;strong&gt;Wilde et al. 2001&lt;/strong&gt;). Their high $\delta^{18}\mathrm{O}$ composition also indicates that the magma was at some point in contact with liquid water (also &lt;strong&gt;Wilde et al. 2001&lt;/strong&gt;): both continents and oceans were present in the Hadean. The presence of liquid water already implies cooler temperature than what was previously thought (&lt;strong&gt;Valley et al. 2002&lt;/strong&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regards to climate per say, the Lithium composition (high concentration, light isotopes) of the zircons (&lt;strong&gt;Ushikobo et al. 2008&lt;/strong&gt;) have been interpreted as evidence of an intense chemical continental weathering. This weathering could have several explanations but one possibility retained by &lt;strong&gt;Ushikobo et al. 2008&lt;/strong&gt; (see also &lt;strong&gt;Sleep 2010&lt;/strong&gt;) is a CO&lt;sub&gt;2&lt;/sub&gt;-rich atmosphere with surface temperatures above 50°C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;&#xA;Sleep, 2010. &lt;a href=&quot;http://cshperspectives.cshlp.org/content/2/6/a002527.full.pdf&quot; rel=&quot;nofollow&quot;&gt;The Hadean-Archaean Environment.&lt;/a&gt; Cold Spring Harbor Perspectives in Biology, 2: a002527.&lt;br&gt;&#xA;Ushikobo, Kita, Cavosie, Wilde, Rudnick &amp;amp; Valley, 2008. &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0012821X08003592#&quot; rel=&quot;nofollow&quot;&gt;Lithium in Jack Hills zircons: Evidence for extensive weathering of Earth's earliest crust&lt;/a&gt;. Earth and Planetary Science Letters, 272: 666-676.&lt;br&gt;&#xA;Valley, Peck, King &amp;amp; Wilde, 2002. &lt;a href=&quot;http://www.geology.wisc.edu/~valley/zircons/Valley2002Cool_Early_Earth.pdf&quot; rel=&quot;nofollow&quot;&gt;A cool early Earth&lt;/a&gt;. Geology, 30: 351-354.&lt;br&gt;&#xA;Wilde, Valley, Peck &amp;amp; Graham, 2001. &lt;a href=&quot;http://www.nature.com/nature/journal/v409/n6817/abs/409175A0.html&quot; rel=&quot;nofollow&quot;&gt;Evidence from detrital zircons for the&#xA;existence of continental crust and oceans on the Earth 4.4 Gyr ago.&lt;/a&gt; Nature, 409: 175-178.&lt;br&gt;&#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2015-02-11T09:50:24.073" LastActivityDate="2015-02-11T09:50:24.073" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4399" PostTypeId="1" AcceptedAnswerId="4401" CreationDate="2015-02-12T01:23:37.417" Score="8" ViewCount="235" Body="&lt;p&gt;I have gone through the website of TRMM that explains how the TRMM satellite gather precipitation data- &lt;a href=&quot;http://pmm.nasa.gov/node/158&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://pmm.nasa.gov/node/158&lt;/a&gt;.  During the Indian Summer Monsoon (ISM), we have synoptic systems that deliver rainfall during the months of June through September. These systems are spread over days and often provide continuous rainfall i.e. they are continuous atmospheric processes. How does the TRMM satellite, which I do not believe is a geostationary satellite, 'continuously' measure the rainfall over a wide region of space? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now one way they could overcome that is they mention they have a dozen such satellites that measure the precipitation but do those dozen satellites coordinate their work as in a &lt;a href=&quot;https://en.wikipedia.org/wiki/A-train_(satellite_constellation)&quot; rel=&quot;nofollow noreferrer&quot;&gt;A-train satellite constellation&lt;/a&gt;? If they do not coordinate their work they probably return to the same location every few hours to make a measurement. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If that is true what sort of assumptions are made  about what happens between these observations from a algorithms perspective to derive precipitation values? &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-05-03T02:18:28.137" LastActivityDate="2019-05-03T02:18:28.137" Title="TRMM rainfall measurement for synoptic systems" Tags="|measurements|remote-sensing|monsoon|rainfall|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="4400" PostTypeId="1" CreationDate="2015-02-12T17:34:13.503" Score="0" ViewCount="403" Body="&lt;p&gt;In diagrams, It is common to depict geological periods to be directly on top of each other with fossils of that period within them. When looking for evidence of this, I have only found examples of trilobites and shells. However it is common to see this sort of ordering depicted with dinosaurs in them &lt;a href=&quot;http://www.globalchange.umich.edu/globalchange1/current/lectures/complex_life/fossil_record.html&quot; rel=&quot;nofollow&quot;&gt;http://www.globalchange.umich.edu/globalchange1/current/lectures/complex_life/fossil_record.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In high school my teacher said that at the grand canyon we find no fossils at the bottom, further up we find shells, above that we find jellyfish, then fish, then reptiles, then mammals. After doing research I found out that this was not the case. Now I suspect that diagrams that depict this ordering of the fossil record with dinosaurs maybe deception or at least a representation of the fossil record that can be easily misinterpreted by laymen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So are there any examples of this ordering with dinosaurs? eg Jurassic layer with Jurassic fossils, then on top of that layer there is a Cretaceous layer with Cretaceous fossils? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: I know the wording of the question is quite terrible. Feel free to edit it.&lt;/p&gt;&#xA;" OwnerUserId="2568" LastEditorDisplayName="user889" LastEditDate="2015-02-14T09:58:36.303" LastActivityDate="2015-02-15T01:09:14.827" Title="Are there any geological periods found on top of each other that have dinosaurs of that period with in them?" Tags="|paleontology|stratigraphy|fossils|evolution|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="4401" PostTypeId="2" ParentId="4399" CreationDate="2015-02-12T17:58:28.783" Score="9" Body="&lt;p&gt;The Tropical Rainfall Measuring Mission (TRMM) satellite is a single satellite, carrying multiple instruments on board, as described &lt;a href=&quot;http://pmm.nasa.gov/TRMM/trmm-instruments&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. It makes a total of 16 orbits/day at a low altitude of 400 km, with different swath widths for each instrument. Thus, the measurement product that you get is not a &quot;continuous&quot; measurement of a single atmospheric phenomenon, but a composite of multiple orbital passes and instruments, where the density of coverage will depend on the time period over which the composite is made.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you take a look at &lt;a href=&quot;http://pmm.nasa.gov/data-access/downloads/trmm&quot; rel=&quot;nofollow noreferrer&quot;&gt;TRMM data access page&lt;/a&gt;, there are 3 levels of data, each level depending on the amount of processing and quality control:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Level 1: Precipitation radar (PR) reflectivity&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Level 2: Combined rainfall profile - PR + Microwave interferometer (TMI)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Level 3: 3-hourly composite of the above + additional data from other instruments (satellites, ground measurements, ground radars), with extended range to 60S - 60N. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Level 1 and 2 data are nearly raw, and are not composites - they give you data from all 16 orbits/day, and each swath cross-section along the orbit will have a timestamp associated with it. Level 3 data will be the most spatially &quot;continuous&quot; of the three, but one must be aware that this is a composite of multiple orbital swaths and multiple instruments, so it is more suitable for slowly evolving (larger scale) systems.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Related: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4239/is-there-a-database-of-global-rainfall-time-series&quot;&gt;Is there a database of global rainfall time series?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-02-12T18:06:17.950" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4403" PostTypeId="2" ParentId="4400" CreationDate="2015-02-13T02:34:47.310" Score="8" Body="&lt;p&gt;There are definitely many examples of overlying Mesozoic strata that contain characteristic dinosaur fossils (and ichnofossils – i.e. trace fossils). One of the best examples is the Mesozoic stratigraphy of &lt;a href=&quot;http://amesgeology.weebly.com/moenkopi-formation.html&quot; rel=&quot;nofollow&quot;&gt;Utah&lt;/a&gt; and Colorado. However, most geologic intervals are characterised by less ‘famous’ fossil material (e.g. molluscs, trilobites or pollen grains). This does not render correlations involving dinosaurs less valid. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider a hypothetical case where some dinosaur footprints are found in a mudstone layer. The mudstone also contains distinctive grains of pollen. In the layer above the mudstone we see no more dinosaur footprints but we still have the same pollen grains. These pollen have been found in other strata (perhaps on the other side of the world!) while the dinosaur foot prints are much more rare. In this case we will be able to correlate these to rock layers much more widely using the pollen than from the dinosaur prints. However, if the mudstone layer is the &lt;em&gt;youngest&lt;/em&gt; geological unit known to contain the fossil remnants of that particular dinosaur species (assuming it had a distinctive footprint) then we can assume that the species became extinct. Extinctions are very useful for correlating the relative age of geological units, therefore the last appearance of the dinosaur footprints will provide a tighter &lt;em&gt;age&lt;/em&gt; control than the pollen (which persists in the rock record).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I should add that stratigraphic corrections based on the fossil record can be very complex. The scientists who study the fossil record (palaeontologists) spend decades trying to decipher the exact details of the evolution of life on this planet preserved in rocks. Due to the complexity of this science it is very easy for a layperson to get confused or make false assessments.&lt;/p&gt;&#xA;" OwnerUserId="2563" LastEditorUserId="2563" LastEditDate="2015-02-15T01:09:14.827" LastActivityDate="2015-02-15T01:09:14.827" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4404" PostTypeId="1" CreationDate="2015-02-13T10:15:32.757" Score="10" ViewCount="95" Body="&lt;p&gt;In the abstract for the article &lt;a href=&quot;http://geology.gsapubs.org/content/35/12/1115.abstract&quot;&gt;Forecasting Etna eruptions by real-time observation of volcanic gas composition&lt;/a&gt; (Aiuppa et al. 2007), the authors assert that real time monitoring of volcanic volatiles, such as $\ce{H2O}$, $\ce{CO2}$ and $\ce{SO2}$ and ratios thereof, could be a potential tool for volcanic eruption prediction, as exemplified by their modelling of Mt. Etna volcanic volatile geochemistry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, at the time of the article, according to the authors,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It is generally accepted, &lt;strong&gt;but not experimentally proven&lt;/strong&gt;, that a quantitative prediction of volcanic eruptions is possible from the evaluation of volcanic gas data.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Has there been experimental proof of the effectiveness of real time monitoring of volcanic volatiles in volcanic eruption prediction?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-02-13T10:36:49.310" LastActivityDate="2015-02-13T10:36:49.310" Title="Predicting volcanic eruptions by experimentally proven volatile outgassing observations" Tags="|volcanology|geochemistry|volcanoes|volcanic-hazard|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4405" PostTypeId="1" AcceptedAnswerId="4472" CreationDate="2015-02-13T11:01:47.293" Score="8" ViewCount="157" Body="&lt;p&gt;This question was inspired by the question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4404/predicting-volcanic-eruptions-by-experimentally-proven-volatile-outgassing-obser&quot;&gt;Predicting volcanic eruptions by experimentally proven volatile outgassing observations&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Depending on the type of volcano, three types of lava are released by current volcanoes on Earth: basalt, andesite and rhyolite. Given the different compositions of each type of lava are there differences in the ratios of volcanic volatiles $\ce{SO2}$, $\ce{CO2}$ and $\ce{H2O}$ associated with each lava type?&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-03-02T21:47:30.480" Title="Do different lavas have different volcanic volatiles associated with them?" Tags="|volcanology|geochemistry|volcanoes|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4406" PostTypeId="2" ParentId="4385" CreationDate="2015-02-13T16:04:31.570" Score="5" Body="&lt;p&gt;WRF model development is done in such a way that users can run the model independently before you start adding more complex options to ingest observations.  There is even an &quot;ideal&quot; mode that new users can take advantage of to learn how the system works (not for simulating real Earth situations).  In &quot;real&quot; mode, there are typically two types of simulations done: a forecast or a retrospective (historical) simulation.  It's important to have real observations ingested into a retrospective simulation, since the intent is to model the event as best you can.  However, this is not possible in forecast mode, since the observations do not yet exist.  So, it is important to have default lookup tables that characterize your unknowns.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding the values in the LANDUSE.tbl, there are many groups that use the monthly MODIS-derived values to ingest into their simulations that replace some of these values.  A &quot;summer&quot; and &quot;winter&quot; lookup table is provided for users in WRF, but those defaults are not appropriate for the best retrospective weather simulations. Forecasting, on the other hand, can use old satellite data (MODIS land-surface data is several days if not weeks old by the time it is processed) but that has error just as a seasonal average would.  The values in the LANDUSE.tbl (except surface roughness) will get overwritten with the VEGPARM.TBL values if you use Noah or the RUC Land Surface Model (LSM). Noah uses monthly values as far as I know. RUC might write values on its own... not really sure if it uses the VEGPARM.TBL or not. I'm sure there are experienced WRF modelers out there that can give you more detailed information, e.g. on the WRF modelers forum.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2015-02-13T16:04:31.570" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4407" PostTypeId="2" ParentId="2844" CreationDate="2015-02-13T16:49:25.637" Score="1" Body="&lt;p&gt;Subduction is ultimately driven by the heat flow process of mantle convection. A mantle plume beneath a stable plate will ultimately cause that plate to split, a la the African rift zone we observe today. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The crust of the earth is very thin compared to the mass of flowing material beneath it. As my global geophysics prof taught us, the fact that the earth has a solid outer &quot;skin&quot; is a consequence of the thermal conditions around the earth's surface and geochemistry, but that has little to no effect on the thermal conditions within the planet that ultimately control thermal convection that expresses itself on the surface as plate motions. I.E., the thermal mass of the crust is inconsequential when considering the thermal mechanisms that drive the mantle and outer core. Heat makes the plate go! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the surface, plates may move, be created or destroyed, but thermodynamics tells us these are consequences, not drivers. We may observe evidence of past situations where plates appear to be static with respect to the underlying mantle motions, but this does not reveal any new mechanism that would suggest plate tectonic theory would not predict such circumstances. &lt;/p&gt;&#xA;" OwnerUserId="2557" LastActivityDate="2015-02-13T16:49:25.637" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4408" PostTypeId="2" ParentId="2812" CreationDate="2015-02-13T16:55:34.237" Score="5" Body="&lt;p&gt;The number of samples in the input binary header from the SEGY file does not match the NSAMP trace header.  I would first confirm: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;What # of samples is in the binary SEG-Y header. &lt;/li&gt;&#xA;&lt;li&gt;The number of samples you expect in each trace&lt;/li&gt;&#xA;&lt;li&gt;Dump the su trace header for     number of samples. You can use&#xA;SUGETHW and the keyword for # of samples is &quot;ns&quot;.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;If the error is in an individual trace header, you can overwrite that with SUSETHW. &lt;/p&gt;&#xA;" OwnerUserId="2557" LastEditorDisplayName="user889" LastEditDate="2015-02-13T18:00:25.077" LastActivityDate="2015-02-13T18:00:25.077" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4409" PostTypeId="2" ParentId="4385" CreationDate="2015-02-13T17:23:04.933" Score="3" Body="&lt;p&gt;For soil mosture you can initialize the model with a dataset that provides that information.  If you are doing historical retrospective you are likely going to initialize from a reanalysis dataset and if you are doing a forecasting case then you are likely initializing from GFS, RAP, HRRR or some other model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the case of initialization from GFS, the grib files you can get from NCEP have soil temperature and moisture for 4 levels 0-0.1 m, 0.1-0.4 m, 0.4-1 m and 1-2m below ground.  The North American Regional Reanalysis (NARR) data a single layer for subsurface soil moisture and temperature available every 3 hours and from daily or monthly means.  The ECMWF reanalysis (ERA-interim) has 4 layers of soil temperature and mositure and a surface roughness.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-02-13T17:23:04.933" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4410" PostTypeId="1" AcceptedAnswerId="4418" CreationDate="2015-02-13T23:34:35.033" Score="12" ViewCount="1298" Body="&lt;p&gt;There is a community wiki question over at &lt;a href=&quot;https://earthscience.stackexchange.com/questions/621/a-good-book-or-source-for-climate-science-and-meteorology-basics&quot;&gt;A good book or source for climate science and meteorology basics?&lt;/a&gt; that talks about meteorology basics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Building on that, but with a slightly different focus, are there &quot;standard texts&quot; for a computer programmer (with engineering background - I get maths, but don't know which math I need to apply) to help understand numerical weather forecasting? If that is too broad, I'm mainly interested in mesoscale and microscale applications.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've tried building and running some of the forecast models (e.g. WRF) but I'm uncomfortable looking at numbers coming out without understanding at least some of the process.&lt;/p&gt;&#xA;" OwnerUserId="2574" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-02-16T19:33:59.683" Title="Numerical weather forecasting - resources for a programmer?" Tags="|meteorology|atmosphere-modelling|nwp|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4413" PostTypeId="2" ParentId="4380" CreationDate="2015-02-14T15:59:23.717" Score="1" Body="&lt;p&gt;The method of drawing circles on a map to find their intersection solves for only one unknown. When the stations are far from the earthquake focus, or the earthquake is shallow, the difference between the distance to the focus and epicenter is ignored. Because many earthquakes are shallow, the three circles often do intersect in a point. When they do not, a possible explanation is that it is because the earthquake is relatively deep (compared to the distance to the epicenter.)   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to try to determine both the epicenter and the depth of the earthquake, then you need to collect more observations (more stations) and use mathematics to solve a system having at least two unknowns. You might use linear algebra.  Note that arrival times for stations closer to the earthquake will be affected by the depth of the focus than stations far, so you would want to try to include stations closer to the earthquake. Secondary school physics student might have had enough math to use the &lt;a href=&quot;http://mathworld.wolfram.com/NewtonsMethod.html&quot; rel=&quot;nofollow&quot;&gt;Newton-Raphson method&lt;/a&gt; method to estimate the depth. They might try to used the initial estimate of the 'epicenter' by the first method, to constrain the equations they try to solve to estimate a depth.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In practice, seismologists collect large amounts of data and have to consider many unknowns - such as distance to focus, but also the variation of seismic velocity through different types of rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you try the three-station and map approach in your Earth Science classroom, the students may notice that all three circles do not go though a single point typically, but come more or less close to doing so. Perhaps this is a good opportunity to discuss the differences between a model and actual earthquakes and Earth. It might even be possible to discuss how a better model can improve the agreement with observations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It looks like this USGS page : &lt;a href=&quot;http://earthquake.usgs.gov/learn/topics/seismology/determining_depth.php&quot; rel=&quot;nofollow&quot;&gt;Determining the Depth of an Earthquake&lt;/a&gt; has a somewhat different answer, which may describe how deep earthquakes were 'discovered' historically :) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.google.com/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=2&amp;amp;cad=rja&amp;amp;uact=8&amp;amp;ved=0CCYQFjAB&amp;amp;url=http%3A%2F%2Fseismo.berkeley.edu%2F~rallen%2Fteaching%2FF04_GEO302_PhysChemEarth%2FLectures%2FL03_EarthquakeSource.pdf&amp;amp;ei=RSbiVIK_FIn0oATKvICICQ&amp;amp;usg=AFQjCNFrvjhZylNXO0hzXuQP2qocuHialw&quot; rel=&quot;nofollow&quot;&gt;This presentation&lt;/a&gt; at the Berkeley Seismographic Station shows a geometric construction and formula for determining earthquake depth.   &lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorUserId="178" LastEditDate="2015-02-16T17:24:40.453" LastActivityDate="2015-02-16T17:24:40.453" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4414" PostTypeId="2" ParentId="2732" CreationDate="2015-02-14T23:32:46.900" Score="8" Body="&lt;p&gt;Try NCL. It has a package for WRF-related functions, including the bidirectional grid-coordinates conversion routine. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To convert coordinate pairs to grid indices, follow the documentation here:&#xA;&lt;a href=&quot;https://www.ncl.ucar.edu/Document/Functions/WRF_arw/wrf_user_ll_to_ij.shtml&quot; rel=&quot;noreferrer&quot;&gt;wrf_user_ll_to_ij&lt;/a&gt;.&#xA;A backward (i.e. gird to coordinate) routine can be found here:&#xA;&lt;a href=&quot;https://www.ncl.ucar.edu/Document/Functions/WRF_arw/wrf_user_ij_to_ll.shtml&quot; rel=&quot;noreferrer&quot;&gt;wrf_user_ij_to_ll&lt;/a&gt;.&#xA;They are quite handy. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For your scenario, you may load your parent domain files (either &lt;code&gt;geo_em&lt;/code&gt; or &lt;code&gt;wrfout&lt;/code&gt; NetCDF files), and then specify the child domain starting coordinate, you will get the results.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are some examples from the official documentation:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Conversion from coordinate to grid indices:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;load &quot;$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl&quot;&#xA;load &quot;$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl&quot;&#xA;a   = addfile(&quot;wrfout_d01_2000-01-24_12:00:00.nc&quot;,&quot;r&quot;)&#xA;loc = wrf_user_ij_to_ll(a, 10., 30., True)&#xA;print(&quot;lon location is: &quot; + loc(0))&#xA;print(&quot;lat location is: &quot; + loc(1))&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Conversion from grid indices to coordinate:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;load &quot;$NCARG_ROOT/lib/ncarg/nclscripts/csm/gsn_code.ncl&quot;&#xA;load &quot;$NCARG_ROOT/lib/ncarg/nclscripts/wrf/WRFUserARW.ncl&quot; &#xA;a = addfile(&quot;wrfout_d01_2000-01-24_12:00:00.nc&quot;,&quot;r&quot;)&#xA;res = True&#xA;res@returnInt = False                             ; return real values&#xA;loc  = wrf_user_ll_to_ij(a, -100.0, 40.0, res)&#xA;print(&quot;X/Y location is: &quot; + loc)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="1376" LastEditorUserId="192" LastEditDate="2015-02-15T17:11:02.783" LastActivityDate="2015-02-15T17:11:02.783" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4415" PostTypeId="1" AcceptedAnswerId="5290" CreationDate="2015-02-14T23:47:07.140" Score="12" ViewCount="2331" Body="&lt;p&gt;As the Sun's luminosity slowly rises, the Earth's surface temperature will climb. Will Earth ever be too warm to have any more glacial periods? If so, when will that be?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: The existing answer misunderstood the question. I'd like some boundary conditions, e.g. &quot;when the sun's luminosity is 10% higher and the Earth becomes a 'moist greenhouse'&quot; and &quot;when the Sun turns Earth into a cinder&quot;. Those conditions would imply that the last Ice Age will happen 1-4 billion years from now. A better estimate would be awesome. Unless there's something I'm missing, with Stefan-Boltzmann and some reasonable assumptions (e.g. linear increase in luminosity) it should be possible to get a back-of-the-envelope calculation for this.&lt;/p&gt;&#xA;" OwnerUserId="2576" LastEditorUserId="2576" LastEditDate="2015-03-06T16:19:41.467" LastActivityDate="2015-08-01T05:32:44.187" Title="When will the Final Ice Age happen?" Tags="|geophysics|climate-change|glaciology|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4416" PostTypeId="2" ParentId="4415" CreationDate="2015-02-15T01:41:48.370" Score="8" Body="&lt;p&gt;At the moment, nobody knows for sure whether or not changes in the Sun's luminosity can cause long-term climate changes. There have been various studies done, most since the advent of global warming, that have tried to address this. The conclusions have been interesting:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The Sun is not responsible for the recent warming of the Earth.&lt;/li&gt;&#xA;&lt;li&gt;It's not yet known whether or not the Sun has influenced climate in the past.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Here are some studies (one supporting each side of the long-term debate):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://science.nasa.gov/science-news/science-at-nasa/2013/08jan_sunclimate/&quot;&gt;A report by the National Research Council&lt;/a&gt; (available &lt;a href=&quot;http://books.nap.edu/openbook.php?record_id=4778&amp;amp;page=R1&quot;&gt;here&lt;/a&gt;) found that sunspot activity could be a major contributor to small changes in the Sun's brightness. There is a periodic trend in sunspot activity that lasts 11 years, and studies have considered this when looking at long-term trends. One target of inquiry is the Maunder Minimum, a period of low sunspot activity:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/2/28/Sunspot_Numbers.png&quot;&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/2/28/Sunspot_Numbers.png&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Maunder Minimum coincided with the Little Ice Age, a short period of low temperatures. In fact, the Sun may be entering a similar period within the next few decades. Observations could show whether or not there is a link between the two events.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the NRC concluded that it is hard, if not impossible, to find any data supporting theories that there is a long-term patter. Hal Maring summarized it best:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Hal Maring, a climate scientist at NASA headquarters who has studied the report, notes that “lots of interesting possibilities were suggested by the panelists.  However, few, if any, have been quantified to the point that we can definitively assess their impact on climate.”&lt;/p&gt;&#xA;&lt;/blockquote&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;In the paper &lt;a href=&quot;http://www.awi.de/fileadmin/user_upload/Research/Research_Divisions/Climate_Sciences/Paleoclimate_Dynamics/Modelling/Methods/PossibleSolar.pdf&quot;&gt;&lt;em&gt;Possible solar origin of the 1,470-year glacial climate cycle demonstrated in a coupled model&lt;/em&gt; by Holger et al.&lt;/a&gt;, periods called Dansgaard–&#xA;Oeschger events were studied. These are climate oscillations lasting 1,470 years. Holger et al. analyzed ice cores from Greenland and attempted to model &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiative_forcing&quot;&gt;solar forcing&lt;/a&gt;, the amount of energy absorbed by Earth or radiated into space. They also used the ocean and atmosphere to account for changes (the NRC report, too, concluded that solar effects can trickle down through the atmosphere and other parts of Earth). Their conclusion was that, despite the fact that no records of 1,470-year solar cycle exist, the analysis supported a connection between solar variability and changes in Earth's climate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Before anyone gets too excited, I'll add this: 1) I haven't been able to find any comments from other scientists on the paper, so I'm not sure how well-received it was, and 2) The 1,470-year cycle can not account for long-term glacial periods, or the recent rise in global temperatures.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Another potentially interesting (and paywalled) paper can be found &lt;a href=&quot;http://www.nature.com/nature/journal/v443/n7108/full/nature05072.html&quot;&gt;here&lt;/a&gt;. An informative website is &lt;a href=&quot;http://www.worldwatch.org/node/4629&quot;&gt;here&lt;/a&gt;, but I'm not sure if it's entirely neutral. It does seem to present both sides, though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll end on this: Whether or not the Sun severely impacts the Earth's climate, Milankovitch cycles are the biggest influence on ice ages.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;It will take some pretty drastic changes in the Sun's luminosity to change the glacial periods . . . which the Sun will be undergoing in about billion years or so. It will still be on the main sequence, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Sun#Main_sequence&quot;&gt;will stay there for 4.4 billion years more&lt;/a&gt;, but &lt;a href=&quot;https://en.wikipedia.org/wiki/Timeline_of_the_far_future&quot;&gt;it will have brightened&lt;/a&gt; by about 10%.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once of the consequences of this will be that &lt;a href=&quot;http://books.google.com/books?id=M8NwTYEl0ngC&amp;amp;pg=PA79#v=onepage&amp;amp;q&amp;amp;f=false&quot;&gt;the Earth will lose its oceans&lt;/a&gt;. Through a process called the &quot;moist greenhouse&quot; effect, water heats up and reaches the atmosphere, where the hydrogen atoms are freed from the oxygen atoms and escape to space. This occurs at a tiny, tiny rate at present, but in about one billion years, the Sun will be bright enough that this will occur at a catastrophic rate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That places the last glacial period somewhere between now and one billion years in the future. To figure this out, we have to look at &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/5/53/MilankovitchCyclesOrbitandCores.png&quot;&gt;long term patterns&lt;/a&gt;, such as Milankovitch Cycles. This graph illustrates them best:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/5/53/MilankovitchCyclesOrbitandCores.png&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the present day to the far right, though, is only 800,000 years. That's unhelpful. &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/9/90/InsolationSummerSolstice65N.png&quot;&gt;This&lt;/a&gt; graph, while a bit clearer, shows only the variations without accounting for any changes in the Sun's luminosity (though that will not affect us during the next 800,000 years!).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/9/90/InsolationSummerSolstice65N.png&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's the actual answer to your question: We don't know. That's because some parts of the Earth will be affected more by the Sun's brightening that others. For example, the NRC found that the Pacific Ocean experienced a strong relationship with solar activity. So as the Sun gets brighter, some areas could still be strongly affected by Milankovitch cycles, while others might find themselves getting hotter than they would normally be.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can be sure of one thing, though: It will certainly be before one billion years from now!&lt;/p&gt;&#xA;" OwnerUserId="1399" LastActivityDate="2015-02-15T01:41:48.370" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="4417" PostTypeId="1" AcceptedAnswerId="4430" CreationDate="2015-02-15T17:57:56.047" Score="12" ViewCount="405" Body="&lt;p&gt;While there are areas with really strong tidal currents in the ocean, these currents tend to be primarily barotropic. My question relates to the largest vertical difference in velocity and it is likely to be baroclinic in nature. What is the location with the largest shear? What is the magnitude of that shear?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="6129" LastEditDate="2020-05-08T17:02:25.403" LastActivityDate="2020-05-08T17:02:25.403" Title="What is the area with the largest velocity vertical shear in the ocean?" Tags="|oceanography|ocean-currents|tides|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4418" PostTypeId="2" ParentId="4410" CreationDate="2015-02-16T18:39:54.973" Score="11" Body="&lt;p&gt;The resources you want will vary on what level of understanding you are seeking.  For example, knowing the math means you can solve equations or transform them, but it doesn't mean you understand the physics involved. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some topics you'll want an understanding of to understand the process:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Physics&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the heart of any weather model are our primitive equations.  Navier-stokes, thermodynamic energy, the state equation, and mass continuity. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Differential equations, linear algebra&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The math for solving the above equations.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Discretization, numerical stability&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How to turn the equations into something than be numerically solved on a 3D grid of points discrete in space and time.  This also involves choices in grid types, grid resolution, boundary conditions and time steps.  Any numeric noise must be accounted for and some artificial diffusion is sometimes used to accomplish this.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Sub-gridscale physics&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A consequence of a grid means that processes smaller than about 4x your grid spacing and certainly those entirely contained within a grid volume are not resolvable by the physics in your equations.  These physics must be parameterized.  These process can include convection, radiation, turbulence, moisture, boundary layer processes and more.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Some books that may assist you include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/1441964118&quot;&gt;Numerical Methods for Fluid Dynamics (Durran, 2010)&lt;/a&gt; (finite difference methods, time stepping schemes, numerical methods)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/0521880688&quot;&gt;Numerical Recipes&lt;/a&gt; (implementations of numerical methods)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/0521126762&quot;&gt;Paramaterization schemes (Stenstrud 2009)&lt;/a&gt; (how to represent sub-gridscale physics in your model)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/0199601429&quot;&gt;Modern Fortran Explained (Metcalf, Cohen and Reid, 2011)&lt;/a&gt; (in the world of models you will be seeing a lot of Fortran and FORTRAN).&lt;/li&gt;&#xA;&lt;li&gt;A good text on MPI (not necessarily needed to understand the model, but if you are interested in how it runs across nodes you'll want to understand MPI).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The next step is digging into the source code.  From this perspective I suggest taking a look at &lt;a href=&quot;http://www2.mmm.ucar.edu/people/bryan/cm1/&quot;&gt;CM1&lt;/a&gt;, which may be easier to follow than WRF from a programming perspective and will give you a foundation for how the math is applied in code to solve our equations and produce the output you see.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-02-16T18:39:54.973" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4421" PostTypeId="2" ParentId="3193" CreationDate="2015-02-17T21:32:54.333" Score="9" Body="&lt;p&gt;I have created composite plots from reanalysis data for the dates as partitioned in the image in the question.  I used the full &lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/gridded/data.narr.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NARR&lt;/a&gt; dataset, which covers 1979 to 2014, so I have a few more years of data than is included in the image above.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What can be seen are largely wintertime climatological means.  A persistent subtropical high off the California coast and persistent lows in the north Pacific and Atlantic.  What does change is the mean extent of arctic air which descends into the US as winter progresses and retreats as spring approaches.  &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Composite NARR MSLP and 500-1000 hPa thickness 1979-2014&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5jWto.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5jWto.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/CCPVI.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;&lt;strong&gt;Figure 1&lt;/strong&gt;. From left to right, top to bottom the dates composited are &lt;em&gt;Dec 1-15, 16-20, 21-25, 26-31, Jan 1-5, 6-10, 11-15, 16-20, 21-25, 26-31, Feb 1-15, 16-28, Mar 1-15 and 16-31&lt;/em&gt;.  MSLP is contoured every 4 hPa.  Thickness is shaded at intervals of 10 dm.  Click the plot for a larger version.&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The signal I can pick out of this is the approaching and retreating cold (using the proxy of 1000-500 mb thickness) that seems to correlate well with the latest dates of cold in the eastern US, particularly in the great lakes and northeast.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I'm seeing in the west is that initially the subtropical high is broad and surface flowing westerlies impinging on the west coast would originate initially at higher latitudes than the do later in the winter.  By January the subtropical high and the low in the north Pacific have re-oriented so the surface flow is coming from around Hawaii.  The western US will also be subject the reduced seasonal temperature fluctuates from its proximity to the Pacific.  Once the area has cooled and equilibrated with the Pacific, temperatures will be stable.  As the continental landmass would lose more energy and cool, the westerlies coming off the Pacific (now relatively warm) counteract this tendency.  Conversely the east with mostly continental air flows experiences large seasonality and has a long-lasted source of very cold air from our neighbors to the north.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Summary&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;The west ceases to cool once it equilibrates with the Pacific, which looks like it happens early in winter (because even though the Pacific is cold, it isn't &lt;em&gt;that&lt;/em&gt; cold).  Westerlies from the ocean heep the west warm.  East of the rockies there is no influence from large bodies of water and a constant source of cold arctic air and so the east continues to cool throughout the winter, until the pattern changes toward spring (and all the snow melts...).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a smaller scale example of how water can have this influence, take a look at during the next extreme cold event in the midwest and great lakes, particularly when air is flowing westerly across Wisconsin and into Michigan.  You will observe a large temperature gradient across Lake Michigan, which keeps Michigan warmer (sometimes much warmer) than Wisconsin.  Later in the winter when the lake is frozen, that benefit is lost and so Michigan tends to be cooler later in winter as it is no longer &quot;shielded&quot; by the lakes.  &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Data&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Data was downloaded from NOAA's North American Regional Reanalysis, accessed 17 Feb 2015.  Files accessed include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;ftp://ftp.cdc.noaa.gov/Datasets/NARR/Dailies/monolevel/prmsl&quot; rel=&quot;nofollow noreferrer&quot;&gt;ftp://ftp.cdc.noaa.gov/Datasets/NARR/Dailies/monolevel/prmsl&lt;/a&gt;*nc&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;ftp://ftp.cdc.noaa.gov/Datasets/NARR/Derived/pressure/hgt.day.ltm.nc&quot; rel=&quot;nofollow noreferrer&quot;&gt;ftp://ftp.cdc.noaa.gov/Datasets/NARR/Derived/pressure/hgt.day.ltm.nc&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="64" LastEditorUserId="200" LastEditDate="2015-02-18T18:26:04.567" LastActivityDate="2015-02-18T18:26:04.567" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4423" PostTypeId="1" CreationDate="2015-02-18T16:29:47.297" Score="6" ViewCount="2182" Body="&lt;p&gt;I recently visited the southern tip of India (State of Tamil Nadu) - it is called Kanyakumari. The beach was beautiful and one thing that struck me was that the sand was multicolored. The local legend is that the Pandava (of Ramayana epic) princess spilt food on the beach which turned the sand multicolor. I'm hoping for a more scientific explanation. Could it be due to particular minerals? I'm certain the striking white sand is due to quartz. Would love to hear the views of this community.&lt;/p&gt;&#xA;" OwnerUserId="2544" LastEditorDisplayName="user889" LastEditDate="2015-02-18T19:06:31.577" LastActivityDate="2015-02-18T20:28:05.407" Title="Sand on the beaches of Kanyakumari, India" Tags="|ocean|sedimentology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4424" PostTypeId="2" ParentId="4423" CreationDate="2015-02-18T20:22:20.227" Score="9" Body="&lt;p&gt;There are a few studies looking at different aspects of the magnificent colours observed at the Kanyakumari region. The colours, according to the research are due to the mineral content therein.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the article &lt;a href=&quot;http://www.indiaenvironmentportal.org.in/files/hydrogeological%20studies.pdf&quot;&gt;Hydrogeological Studies of the Coastal Areas of Kanyakumari to Colachel after Tsunami, South Tamil Nadu&lt;/a&gt;, (Perumal et al. 2010), it is common for zircon, rutile, ilmenite and garnet to be observed in the sand - this can acount for reddish hues.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In some places, monazite has been noted, also noted in radiological studies in &lt;a href=&quot;http://iosrjournals.org/iosr-jestft/papers/vol8-issue9/Version-3/A08930104.pdf&quot;&gt;Baseline Assessment of dose due to Natural Radionuclides in soils of coastal regions of Kanyakumari district in Tamil Nadu, India&lt;/a&gt; (Sarojini, 2014).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to a &lt;a href=&quot;http://www.portal.gsi.gov.in/gsiImages/information/misc_pub_30_tamilnadu_2006_wm.pdf&quot;&gt;Geological Survey of India&lt;/a&gt; (GSI) report of the region, there are also small amounts of sillimanite and leucoxene.  They also state that there is between 10-25% silica sand content. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The presence of zircons, causing some of the brilliant lustre, was confirmed by XRD analysis discussed in the article &lt;a href=&quot;http://link.springer.com/article/10.1007/s12594-010-0119-4&quot;&gt;Observations on the reported incidence of micro-diamonds in the beach sands of the Kanyakumari Coast, Tamil Nadu&lt;/a&gt; (Dinesh et al. 2011).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Much of the beach sand sources are likely to be weathered from the surrounding gneissic (including garnetiferous gneisses) and charnockites, as described in Perumal et al. and the GSI report.  Additionally, the report &lt;a href=&quot;http://cdn.intechopen.com/pdfs-wm/24943.pdf&quot;&gt;Post Tsunami Heavy Mineral Distribution&#xA;Between Cuddalore to Kanyakumari Along the&#xA;Tamil Nadu Coast, India – A Review &lt;/a&gt; that also suggest some offshore and alongshore sources of the heavy minerals.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-02-18T20:28:05.407" LastActivityDate="2015-02-18T20:28:05.407" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4425" PostTypeId="1" CreationDate="2015-02-19T08:55:32.397" Score="19" ViewCount="3418" Body="&lt;p&gt;Because of photosynthesis, obviously.  But then it's not actually that obvious after all, because photosynthesis is mostly balanced by respiration. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can summarise the processes of photosynthesis and respiration like this:&#xA;$$\begin{align}&#xA;\ce{CO2 + H2O + h\nu} &amp;amp; \rightarrow \ce{O2 + CH2O(biomass)} \\&#xA;\ce{O2 + CH2O(biomass)} &amp;amp; \rightarrow \ce{CO2 + H2O}&#xA;\end{align}&#xA;$$&#xA;If these two reactions were always balanced then the concentration of $\ce{O2}$ would never have changed. If I understand correctly, there are abiotic processes that deplete $\ce{O2}$ to form iron oxides, and so in order for there to be persistent $\ce{O2}$ in the Earth's atmosphere, the biosphere as a whole must continually produce an excess of it. In order for this to happen, there must be some processes that consume biomass at a non-neglible rate without removing a corresponding amount of $\ce{O2}$ from the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is, what are the processes primarily responsible for this? Is it just due to the burial of unoxidised organic matter (to form coal, oil, etc.), or is there more to it than that?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If they are different processes, I'm interested both in what caused the excess of oxygen during the &quot;great oxidation&quot; event, and what maintains the excess of oxygen on the modern Earth.&lt;/p&gt;&#xA;" OwnerUserId="215" LastEditorDisplayName="user12525" LastEditDate="2019-04-25T16:34:09.940" LastActivityDate="2019-04-25T16:34:09.940" Title="Why does Earth have abundant oxygen in the atmosphere?" Tags="|atmosphere|geochemistry|biogeochemistry|geobiology|great-oxidation-event|" AnswerCount="3" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="4426" PostTypeId="1" CreationDate="2015-02-19T09:55:30.390" Score="12" ViewCount="553" Body="&lt;p&gt;At the time of writing, areas around the Northern Territory (TC Lam) and Queensland (TC Marcia) in Australia are in the path of severe cyclones (category 4 at the moment, with the Queensland one - TC Marcia predicted to reach category 5 - &lt;a href=&quot;http://en.m.wikipedia.org/wiki/Tropical_cyclone_scales#Australia_and_Fiji&quot; rel=&quot;nofollow noreferrer&quot;&gt;Category scales used for Australia and Fiji&lt;/a&gt;).  These cyclones seem to be connected by a monsoonal trough, as indicated by the dashed line in the weather map below from Australia's &lt;a href=&quot;http://www.bom.gov.au&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bureau of Meteorology&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/kJnpr.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: it is summer here at the moment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, these cyclones are a very large distance apart (about 1900km in a direct line), and these cyclones are not merging at all.  According to the Meteorological Bureau, TC Lam is moving south through the Arnhem Land area of the Northern Territory; and TC Marcia is going to 'hook' when it goes inland and head towards the Brisbane area to the south coast of Queensland (but it is expected to weaken to a tropical low well before then).  The projected paths (based on latest and consistent information from the Bureau) is shown as red arrows in the image below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/9h7Xh.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is the meteorological mechanism that has resulted in the linked &quot;double&quot; severe cyclone event?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Edit - update: TC Lam has made landfall at cat 4, TC Marcia is now making landfall at cat 5&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="2470" LastEditorDisplayName="user889" LastEditDate="2019-03-26T15:54:44.920" LastActivityDate="2019-03-26T15:54:44.920" Title="Two severe cyclones connected by a monsoonal trough" Tags="|meteorology|tropical-cyclone|severe-weather|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="4427" PostTypeId="1" AcceptedAnswerId="4436" CreationDate="2015-02-19T15:17:00.757" Score="8" ViewCount="888" Body="&lt;p&gt;Edmund Halley viewed the monsoon as a glorified sea breeze circulation fueled by different heat capacities of land and ocean. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The resulting meridional temperature gradient between warmer air of the land and cooler air of the ocean  fueled by heating caused by the Sun were thought to cause precipitation in the Indian subcontinent. However, there has been tremendous progress in recent times and a broad consensus has been reached on the climatology of the the Indian Summer Monsoon. Several groups of scientists are converging on the land - ocean - atmosphere coupling model as an explanation of the causes of the Indian Summer Monsoon. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the salient features of the new understanding of the land sea atmosphere coupling model? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question does NOT refer to causes of the interannual variability of the Indian Summer Monsoon but the climatological causes of the Indian Summer Monsoon.&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user889" LastEditDate="2015-02-21T01:55:59.250" LastActivityDate="2015-02-21T13:58:16.303" Title="Climatology of the Indian Summer Monsoon - A modern consensus" Tags="|climatology|monsoon|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4429" PostTypeId="2" ParentId="4384" CreationDate="2015-02-19T17:32:55.107" Score="6" Body="&lt;p&gt;I think you &lt;em&gt;may&lt;/em&gt; have misunderstood the abstract of the paper, which says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Various human activities, including fossil fuel combustion and forest&#xA;  clearing, emit about eight petagrams (or billion tons) of carbon in&#xA;  the form of CO2 into the atmosphere annually. The global ocean absorbs&#xA;  about two petagrams of CO2, and about a half of that amount is&#xA;  absorbed by the Southern Ocean south of 30°S, thus slowing the rapid&#xA;  accumulation of CO2 in the atmosphere. Partial pressure of CO2 (pCO2)&#xA;  is a measure of the chemical driving force for the CO2 exchange&#xA;  between the ocean and the atmosphere. This paper discusses its space&#xA;  and time distribution over the Southern Ocean. &lt;strong&gt;The major sink zone for&#xA;  atmospheric CO2 is located in a latitude belt between 30°S and 50°S&lt;/strong&gt;,&#xA;  where the biological utilization of CO2 and cooling of warm&#xA;  subtropical waters flowing southward produce low seawater pCO2. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Note that most of the &quot;half of the global ocean total absorption&quot; occurs in a band between 30°S and 50°S.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Strong&#xA;  winds in this zone also enhance the ocean's uptake. Although the&#xA;  source-sink conditions vary over a wide range through the seasons &lt;strong&gt;in&#xA;  the areas south of 50°S&lt;/strong&gt;, this zone is a small sink on an annual&#xA;  average. Winter observations show that surface water pCO2 values in&#xA;  the source region for Antarctic Intermediate Water have increased at a&#xA;  rate faster than the atmospheric increase rate, suggesting that the&#xA;  ocean CO2 sink intensity has been weakening for several decades and&#xA;  has changed from a net sink to a net source since 2005. The results of&#xA;  ocean general circulation-biogeochemistry model studies are found to&#xA;  be consistent with the observations.*&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The &quot;net sink to a net source since 2005&quot; appears to relate to this area south of 50°S, which was only a small sink to begin with.  This suggests that the southern ocean as a whole is still a strong carbon sink.  As the evidence for an increase in the airborne fraction increasing is currently equivocal, this suggests that the natural carbon sinks (including the southern ocean) is still strengthening in response to increasing atmospheric concentrations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note the conclusion of the paper talks of the 30°S and 50°S being a sink in the present tense, which would be inappropriate if it had become a net source since 2005.&lt;/p&gt;&#xA;" OwnerUserId="624" LastEditorUserId="624" LastEditDate="2015-02-19T17:50:31.790" LastActivityDate="2015-02-19T17:50:31.790" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4430" PostTypeId="2" ParentId="4417" CreationDate="2015-02-19T20:29:39.157" Score="6" Body="&lt;p&gt;Areas associated with velocity shear at a stratified interface are notably strong in the region of the Equatorial Undercurrent, straits (ex: strait of Gibraltar, the Bosphorus) and regions of the thermocline where internal waves are strong (South China Sea).&lt;/p&gt;&#xA;&lt;p&gt;These areas are typically associated with strong turbulence as a direct result of the strong velocity shear and shear instabilities that trigger Kelvin–Helmholtz billows (if the Richardson number is less than 1/4 for a sufficient amount of time) and subsequent hydrostatically unstable configurations and mixing.&lt;/p&gt;&#xA;&lt;h2&gt;Examples of magnitude of shear:&lt;/h2&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Maximum in &lt;strong&gt;Equatorial Undercurrent&lt;/strong&gt;: &lt;span class=&quot;math-container&quot;&gt;$du/dz \approx 0.02$&lt;/span&gt; s&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;At the base of the mixed layer but above the core of the Equatorial Undercurrent the shear is the largest. See plot from Peters et al (1988) &lt;a href=&quot;https://i.stack.imgur.com/5bfWb.png&quot; rel=&quot;noreferrer&quot;&gt;https://i.stack.imgur.com/5bfWb.png&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;East of the Carmarinal Sill in the &lt;strong&gt;strait of Gibraltar&lt;/strong&gt;: &lt;span class=&quot;math-container&quot;&gt;$du/dz \approx 0.024$&lt;/span&gt; s&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;In the Mediterranian, water flows westward into the Gulf of Cadiz as an undercurrent through the strait of Gibraltar, as these waters make a sharp turn northward, they may give rise to sub-surface eddies or &amp;quot;Meddies&amp;quot; when encountering canyons and underwater bathymetric features off the west coast of Portugal.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Very large amplitude &lt;strong&gt;internal waves in the South China Sea&lt;/strong&gt;: &lt;span class=&quot;math-container&quot;&gt;$du/dz \approx 0.05$&lt;/span&gt; s&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;In the South China Sea very large amplitude internal solitary waves are ubiquitous features propagating on the thermocline with inherently large shear across the interface. See plot from Lien et al (2014)  &lt;a href=&quot;https://i.stack.imgur.com/R2yTZ.png&quot; rel=&quot;noreferrer&quot;&gt;https://i.stack.imgur.com/R2yTZ.png&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;hr /&gt;&#xA;&lt;h2&gt;References:&lt;/h2&gt;&#xA;&lt;p&gt;Ren-Chieh Lien, Frank Henyey, Barry Ma, and Yiing Jang Yang, 2014: Large-Amplitude &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/JPO-D-13-088.1&quot; rel=&quot;noreferrer&quot;&gt;Internal Solitary Waves Observed in the Northern South China Sea: Properties and Energetics. J. Phys. Oceanogr., 44, 1095–1115.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.annualreviews.org/doi/pdf/10.1146/annurev.fl.23.010191.002323&quot; rel=&quot;noreferrer&quot;&gt;Fernando, Harindra JS. &amp;quot;Turbulent mixing in stratified fluids.&amp;quot; Annual Review of Fluid Mechanics 23.1 (1991): 455-493.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://books.google.com/books?hl=en&amp;amp;lr=&amp;amp;id=Ax2d94PODgIC&amp;amp;oi=fnd&amp;amp;pg=PR11&amp;amp;dq=thorpe%20a%20turbulent%20ocean&amp;amp;ots=MdWePVMqQB&amp;amp;sig=PAedziCIgqklqVBE62JsVmTf2SQ&quot; rel=&quot;noreferrer&quot;&gt;Thorpe, Steve A. The turbulent ocean. Cambridge University Press, 2005.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/JC093iC02p01199/full&quot; rel=&quot;noreferrer&quot;&gt;Peters, H., M. C. Gregg, and J. M. Toole. &amp;quot;On the parameterization of equatorial turbulence.&amp;quot; Journal of Geophysical Research: Oceans (1978–2012) 93.C2 (1988): 1199-1218.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-02-19T20:29:39.157" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4431" PostTypeId="1" AcceptedAnswerId="4432" CreationDate="2015-02-20T11:04:57.463" Score="26" ViewCount="23000" Body="&lt;p&gt;I have been set the task of researching plate tectonics, specifically:&#xA;&lt;i&gt;&quot;Why was its discovery so important in its time and controversial?&quot;&lt;/i&gt;&#xA;I do not need a long answer, although more detail is always appreciated. &lt;/p&gt;&#xA;" OwnerUserId="2592" LastEditorUserId="18081" LastEditDate="2023-08-15T13:25:43.500" LastActivityDate="2023-08-15T13:25:43.500" Title="Why was the initial theory of plate tectonics so controversial?" Tags="|plate-tectonics|history-of-science|" AnswerCount="5" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4432" PostTypeId="2" ParentId="4431" CreationDate="2015-02-20T13:52:18.453" Score="21" Body="&lt;p&gt;One of the key aspects of plate tectonics is continental drift.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The person who came up up with the theory of continental drift was &lt;a href=&quot;https://en.wikipedia.org/wiki/Alfred_Wegener&quot;&gt;Alfred Wegener&lt;/a&gt;. He published his theory in 1912.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the issues with the theory that geologists at the time had, was that Wegener was not a geologist, but a meteorologist. He was publishing a theory that wasn't associated with his field of science. The other issue the geologists had was based on the commonly held opinion:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;that the oceanic crust was too firm for the continents to &quot;simply plough through&quot;.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When he published his theory, Wegener did not propose a means by which the different land masses could break away from each other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Initially, some geologists could only conceive the idea that ocean waves might be responsible for breaking up land masses, but they couldn't reconcile the fact that the lack of sediments and the clean breaks in land masses would not support Wegener's theory. Without knowing about plate tectonics the theory of continental drift was difficult to support.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another reason why Wegener's idea was not initially accepted was because of the way he proposed that continents used to fit together. This was because of the assumption most people had was that the continents split along the lines of coast lines and not the 200 m isobath proposed by Wegener.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wegener came up with the idea of continental drift by noticing that all the major land masses appeared to fit together like a jigsaw puzzle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It wasn't until the early 1950s when data from paleomagnetic studies of India showed that India had once been in the southern hemisphere that data started to support Wegener's theory. Also, it wasn't until the 1960s that sea floor spreading data was available to support the theory.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2015-02-22T00:04:37.083" LastActivityDate="2015-02-22T00:04:37.083" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="4433" PostTypeId="2" ParentId="525" CreationDate="2015-02-20T14:32:47.277" Score="3" Body="&lt;p&gt;April and later ice cover is primarily on Lake Superior, since this lake is in the coldest region and also because it is the largest lake.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Raymond Assel analyzed the Great Lakes ice coverage for the winters of 1897-1982 in &lt;a href=&quot;http://www.glerl.noaa.gov/pubs/fulltext/1990/19900009.pdf&quot; rel=&quot;nofollow&quot;&gt;AN ICE-COVER CLIMATOLOGY FOR LAKE ERIE AND LAKE SUPERIOR FOR THE WINTER SEASONS 1897-1898 to 1982-1983&lt;/a&gt; INTERNATIONAL JOURNAL OF CLIMATOLOGY, VOL. 10,731-748 (1990).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to table IV of Assel, in the winter of 1911-12 Lake Superior had an ice cover of 80% or greater for 74 days.  No other winter had more than 52 such days.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;http://coastwatch.glerl.noaa.gov/statistic/ice/dat/g2013_2014_ice.dat&quot; rel=&quot;nofollow&quot;&gt;this NOAA file&lt;/a&gt; in the winter of 2013-14 Lake Superior has an ice cover of 80% or greater on 68 days.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assel also studied Lake Erie, and finds that 1911-12 had 72 days with 80% or greater ice cover.  This compares to 70 such days in 2013-14.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Based on the above, it is very likely that 1911-12 was the most recent winter with similar April ice cover to 2013-14.&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2015-02-20T17:20:22.990" LastActivityDate="2015-02-20T17:20:22.990" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4434" PostTypeId="2" ParentId="4431" CreationDate="2015-02-20T23:41:22.140" Score="11" Body="&lt;p&gt;Plate tectonic theory integrated data from many sub-disciplines of geoscience including the new area of paleomagnatism as noted above, but also seismology, structural geology, bathymetry, stratigraphy, and others. I have a book on earthquakes from the early 1960's that clearly shows the earthquakes along subduction zones but are presented as a curious observation, since the concept of subduction hadn't been developed. Plate tectonics upset some previously widely held models like geosynclinal structures or at least required that they be modified greatly. Much of the observation and testing of the theory happened over time so initially there were inherently questionable aspects. That's science.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One could speculate on controversy due to people ferreting around in their own area of expertise and developing explanations that are at odds with data from other areas but much is due to the development of extensive data sets to show the big picture. But certainly people have a tendency to be personally vested in their own theories and that, too, is needed to demonstrate the robustness of new ideas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not sure the discovery is so important 'in its time' - it made its own importance and would have been so whenever it was developed.  It did have importance in providing models for resource exploration to meet the rapidly increasing demands of the time.  It also provided tangible benefit from the large government and private investment in science and technology of the period.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2015-02-20T23:41:22.140" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4435" PostTypeId="2" ParentId="2965" CreationDate="2015-02-21T09:42:13.760" Score="9" Body="&lt;p&gt;The answer might lie in aerobic respiration. This is of course only one of the many possible explanations but mitochondria (and therefore $\ce{O2}$-breathing eukaryotes) are thought to have evolved circa 2.3 to 1.8 Ga (see for instance &lt;strong&gt;&lt;a href=&quot;http://www.biomedcentral.com/content/pdf/1471-2148-1-4.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hedges et al., 2001&lt;/a&gt;; &lt;a href=&quot;http://www.hedgeslab.org/pubs/156.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;2004&lt;/a&gt;; &lt;a href=&quot;http://www.hedgeslab.org/pubs/182.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;2006&lt;/a&gt;&lt;/strong&gt;). This loose age bracket however is based primarily on molecular data with very few fossil evidence (as I mentioned in an &lt;a href=&quot;https://earthscience.stackexchange.com/a/106/87&quot;&gt;earlier answer of mine&lt;/a&gt;, the Proterozoic fossil record of eukaryotes is almost inexistant).&lt;br&gt;&#xA;An earlier apparition of aerobic respiration is unlikely (e. g. &lt;strong&gt;&lt;a href=&quot;https://books.google.de/books?id=C-siB8GDLGwC&amp;amp;lpg=PA21&amp;amp;ots=ryvu9rVuV4&amp;amp;dq=mitochondria%20evolution%20proterozoic&amp;amp;lr&amp;amp;pg=PA21#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;Knoll &amp;amp; Holland, 1995&lt;/a&gt;&lt;/strong&gt;) as a certain level of $p_{\ce{O2}}$ needed to be reached for this metabolism to be possible.&lt;br&gt;&#xA;If aerobic eukaryotes expanded rapidly they might have constituted a strong enough sink of oxygen, which could be responsible for the drop observed by &lt;strong&gt;&lt;a href=&quot;http://dx.doi.org/10.1038/nature08266&quot; rel=&quot;nofollow noreferrer&quot;&gt;Frei et al., 2009&lt;/a&gt;&lt;/strong&gt;.&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-04-20T08:41:08.000" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4436" PostTypeId="2" ParentId="4427" CreationDate="2015-02-21T12:54:51.147" Score="8" Body="&lt;p&gt;The Indian Summer Monsoon(ISM) has several layers of complexity as it involves interactions between land, sea and atmosphere. This answer will focus on the state of the art overall understanding of the ISM and provide a summary of the salient features of the interactions between land, sea and atmosphere. In general it should be noted that while some references may talk of Land - Atmosphere interactions and Ocean - Atmosphere interactions it is almost impossible to differentiate between the role of land - atmosphere interaction and that of the  ocean -atmosphere  separately and the two processes should be considered to be part of the overall land - atmosphere - ocean interaction especially in the context of Asian Summer Monsoon[1]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Seasonal transition from boreal spring to  summer causes heating of the Asian landmass faster than the  surrounding oceans owing to the difference in heat capacities in land and sea leading to the establishment of a meridional temperature gradient [2]. The land retains  a shorter climate &quot;memory&quot; than the ocean [1].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) The presence of the Himalayas(oriented east west) and Tibetan plateau ensures that sensible heating occurs aloft as well. The implications of the elevated sensible heating are that not only is the meridional temperature gradient present at the surface but aloft as well and  thereby &quot;tethering&quot; the monsoon onset [2] [3]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) Formation of a surface heat low pressure over the Indian subcontinent during the late boreal spring that ensures a cross equatorial flow due to the north south pressure gradient at the low level and return cross equatorial flow aloft. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;4) Thermodynamic conditions caused by the solar heating in boreal spring and early summer cause the seasonal migration of the Inter Tropical Convergence Zone also known as the Monsoon Trough(MT) [4]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;5) Seasonal migration of the Mascarene High from it's December January February(DJF) position over the south eastern Indian Ocean at 85 E 30 S to June July August(JJA) position over the southern Western Indian Ocean near 55 E 30 S[5]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;6) The role of East African Highlands(oriented north-south) in blocking the low level easterly flow and steering the winds across the equator into the south westerly monsoon flow. Without orographic influence of the East African Highlands  the south easterly winds that blow across the equator would blow over East Africa and the Atlantic rather than being transformed into the Somali Jet[5]. A GCM simulation study in which the orographic influence of the African Highlands were removed showed  that the Highlands have a huge influence on the monsoonal flow[6]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;7) The Findlater Jet otherwise known as the Somali Jet gathers momentum due to the Earth's rotation [7]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;8) A wind evaporation feedback mechanism is responsible for rapid onset as well as intensification  [8] &lt;/p&gt;&#xA;&#xA;&lt;p&gt;9) Initial monsoon onset is attributed to sensible heating but after the monsoon has set it is latent heat that drives the monsoon.[9]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;10) Interactions between extra tropical eddies and meridional overturning circulation modelled as feedback. This study is remarkable as it shows that the onset of monsoon can be modelled in the absence of surface in-homogeneities as well as hydrological cycle [10]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;11) The poleward extent of the monsoonal precipitation has been attributed to the &quot;ventilation effect&quot;. At mid latitudes westerly winds advect air with low moist static energy from the cool oceans of the continent which tends to balance incoming solar radiation [11] [12]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;12) Oceans contribute by changing SSTs and the Indian Ocean sees a large surface positive heat flux during the boreal spring and summer which is balanced by net southward transport of heat across the equator and increase of heat storage across the upper ocean [13] &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally it must be mentioned that not all of the coupled feedbacks have been fully explored in general circulation models or in observations [14]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1] Yasunari, T. Role of Land - Atmosphere Interaction on Asian Monsoon climate. J.O.M. S. of Japan, Vol. 85 B, pp.55-75, 2007&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[2] Li, C. F. &amp;amp; Yanai, M. The onset and interannual variability of the Asian summer monsoon in relation to land sea thermal contrast. J. Clim. 9, 358–375 (1996).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[3]Fasullo, J. &amp;amp; Webster, P. J. A hydrological definition of Indian monsoon onset and withdrawal. J. Clim. 16, 3200–3211 (2003).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[4]Prive, N. C. &amp;amp; Plumb, R. A. Monsoon dynamics with interactive forcing. Part I: Axisymmetric studies. J. Atmos. Sci. 64, 1417–1430 (2007).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[5]Slingo, J., Spencer, H., Hoskins, B., Berrisford, P. &amp;amp; Black, E. The meteorology of the western Indian Ocean, and the influence of the East African highlands. Phil. Trans. R. Soc. A 363, 25–42 (2005).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[6]Rodwell, M. J. &amp;amp; Hoskins, B. J. 1995 A model of the Asian Summer Monsoon. II. Crossequatorial flow and PV behavior. J. Atmos. Sci. 52, 1341–1356.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[7] Findlater, J. A major low-level air current near the Indian Ocean during northern summer: Interhemispheric transport of air in the lower troposphere over western Indian Ocean. Q. J. R. Meteorol. Soc. 96, 551–554 (1970).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[8] Boos, W. R. &amp;amp; Emanuel, K. A. Annual intensification of the Somali jet in a quasi-equilibrium framework: Observational composites. Q. J. R. Meteorol. Soc. 135, 319–335 (2009).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[9] Chou, C. Land-sea heating contrast in an idealized Asian summer monsoon. Clim. Dynam. 21, 11–25 (2003).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[10] Bordoni, S. &amp;amp; Schneider, T. Monsoons as eddy-mediated regime transitions of the tropical overturning circulation. Nature Geosci. 1, 515–519 (2008).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[11] Chou, C., Neelin, J. D. &amp;amp; Su, H. Ocean-atmosphere-land feedbacks in an idealized monsoon. Q. J. R. Meteorol. Soc. 127, 1869–1891 (2001)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[12] Chou, C. &amp;amp; Neelin, J. D. Mechanisms limiting the northward extent of the northern summer monsoons over North America, Asia, and Africa. J. Clim. 16, 406–425 (2003).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[13] Loschnigg, J. &amp;amp; Webster, P. J. A coupled ocean-atmosphere system of SST modulation for the Indian Ocean. J. Clim. 13, 3342–3360 (2000).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[14]Turner, A. G. and Annamalai, H.  Climate change and the South Asian summer monsoon. Nature Climate Change, 2. pp. 587-595.(2012) &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorUserId="2470" LastEditDate="2015-02-21T13:58:16.303" LastActivityDate="2015-02-21T13:58:16.303" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4437" PostTypeId="2" ParentId="4431" CreationDate="2015-02-22T19:12:38.297" Score="14" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Why was the initial theory of plate tectonics so controversial?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Plate tectonics was anything but controversial. A mere four or five years expired between its original proposal in 1963 by J.T. Wilson and its almost universal acceptance in 1967 or 1968.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What was controversial was Wegener's theory of continental drift. His theory was not plate tectonics. Plate tectonics had answers to almost all of the questions that Wegener's theory did not and could not address.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wegener's theory was based partially on the shapes of the eastern coasts of the Americas versus the shapes of the western coasts of Europe and Africa. Wegener was hardly the first to notice this similarity. What Wegener added was fossil evidence; there appeared to be something much deeper than a mere random similarity of coastlines. What Wegener didn't add was a mechanism.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What he did add was &lt;em&gt;exactly&lt;/em&gt; what geologists had been fighting for about a hundred years, which was religion. Nineteenth century geology was a battle between those who believed in the Bible (literally) and those who looked at the geological evidence. Early nineteenth century geologists explained the diversity of the Earth's geology via catastrophism, with Noah's flood playing a predominant role. Later geologists looked at the evidence and saw no signs of catastrophes. They instead adopted a theory of uniformitarianism.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One big problem was the 1920s Scopes trial in the US. Scientists in the US were hard pressed at the time. One counter reaction amongst the American scientific community to the Scope trial  was a rejection of anything and everything that remotely hinted of religious catastrophism. This included Wegener's continental drift.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plate tectonics is not Wegener's continental drift. Unlike Wegener's continental drift, plate tectonics has a mechanism. Plate tectonics is founded on a lot more than a mere similarity of continental outlines. A mountain of evidence had accumulated in the time that intervened between Wegoner's unfounded claims and J. Tuzo Wilson's 1963 article that proposed plate tectonics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The evidence that turned plate tectonics into the accepted science in five short years included&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The recognition of a single, globe-spanning mid-ocean ridge.&lt;br&gt;&#xA;Scientists had discovered bits and pieces of this ridge long before, but recognizing that it was continuous and globe-spanning didn't happen until after World War II. (Wars are good for developing technology).&lt;/li&gt;&#xA;&lt;li&gt;The recognition of very deep oceanic trenches.&lt;br&gt;&#xA;These are the flip side of the mid-ocean ridges, and these (along with the mid-ocean ridge) were a key to understanding seafloor spreading. Technologies developed during World War II were once again the key.&lt;/li&gt;&#xA;&lt;li&gt;The recognition of magnetic field reversals.&lt;br&gt;&#xA;Yet again, technologies developed during World War II were key. This showed the oceanic crust originated from the mid-ocean ridges, and died in the deep trenches.&lt;/li&gt;&#xA;&lt;li&gt;The recognition of the Ring of Fire.&lt;br&gt;&#xA;Here it was post-WWII technologies that came into play. While seismographs existed during Wegener's time, they were rather crude devices compared to those needed to determine whether ones enemies (or for that matter, whether ones supposed allies) were conducting illicit atomic tests.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="239" LastEditorUserId="1242" LastEditDate="2015-02-22T21:57:39.550" LastActivityDate="2015-02-22T21:57:39.550" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="4438" PostTypeId="1" CreationDate="2015-02-22T22:17:48.883" Score="11" ViewCount="2458" Body="&lt;p&gt;According to the &lt;a href=&quot;http://www.bom.gov.au/cyclone/about/&quot; rel=&quot;noreferrer&quot;&gt;Australia Bureau of Meterology&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Research has shown that cyclones in the Australian region exhibit more&#xA;  erratic paths than cyclones in other parts of the world. A tropical&#xA;  cyclone can last for a few days or up to two or three weeks. Movement&#xA;  in any direction is possible including sharp turns and even loops.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/VwoOf.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why do they change directions so radically?  Does this occur in other parts of the world or are North American hurricanes the anomaly in their typically smooth tracks?&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2015-02-23T02:19:27.220" Title="Why do tropical cyclones around Australia have erratic paths?" Tags="|meteorology|tropical-cyclone|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="4439" PostTypeId="1" AcceptedAnswerId="4571" CreationDate="2015-02-23T00:17:22.693" Score="6" ViewCount="1467" Body="&lt;p&gt;Hurricane Katrina was one of the deadliest and most destructive hurricane to hit the US. After looking into the minimum sea-level pressure (MSLP) and maximum wind speed (MWS) intensity data from NOAA's HURDAT database, I am confused with the pattern or whether there actually is one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For Katrina specifically, is there a pattern in the relationship between MSLP and MWS intensity? What role does a low or high air pressure system play in the velocity vector of the hurricane?&lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="192" LastEditDate="2015-03-23T14:47:40.547" LastActivityDate="2017-11-16T02:48:29.997" Title="Minimum sea-level pressure and maximum wind speed intensity relationship in Hurricane Katrina (2005)" Tags="|meteorology|tropical-cyclone|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4440" PostTypeId="2" ParentId="4438" CreationDate="2015-02-23T02:19:27.220" Score="7" Body="&lt;p&gt;The paths of cyclones in the Australian Basin are no more erratic than cyclones, hurricanes or typhoons elsewhere. Conditions at the time of a cyclone's existence determine its path.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0143622813001975&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sinuosity of Cyclone Tracks - SW Indian Ocean&lt;/a&gt; states that over the past three decades the sinuosity of cyclone paths in the SW Indian Ocean has a high degree of variability. It appears that in that part of the world, cyclones can make more abrupt changes in their paths during January than in other months of the cyclone season. It also goes on the state there are marked periods when the paths of cyclones are less sinuous and other periods when they are more sinuous when compared with long term averages.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following picture, from Wikipedia, shows the paths of the cyclone tracks for the 1988-89 south west Indian Ocean cyclone season. A number of the paths are erratic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/feKTJ.jpg&quot; alt=&quot;SW Indian Ocean Cyclones 1988-89&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Paths of other cyclones can be seen on the following Wikipedia pages:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/1988%E2%80%9389_South-West_Indian_Ocean_cyclone_season&quot; rel=&quot;nofollow noreferrer&quot;&gt;1988-89 SW Indian Ocean Cyclone Season&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/1988%E2%80%9389_Australian_region_cyclone_season&quot; rel=&quot;nofollow noreferrer&quot;&gt;1988-89 Australian Cyclone Season&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/2013%E2%80%9314_South-West_Indian_Ocean_cyclone_season&quot; rel=&quot;nofollow noreferrer&quot;&gt;2013-2014 SW Indian Ocean Cyclone Season&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.thefullwiki.org/1985%E2%80%9390_Southern_Hemisphere_tropical_cyclone_seasons&quot; rel=&quot;nofollow noreferrer&quot;&gt;1985-1990 Southern Hemisphere Cyclone Paths&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.wired.com/2013/08/hurricane-tracks/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Paths of the World Hurricanes, Cyclones &amp;amp; Typhoons for the past 170 Years&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://coast.noaa.gov/hurricanes/?redirect=301ocm&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA Site displaying the paths of past cyclones, hurricanes &amp;amp; typhoons&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.cyclocane.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tracking paths for current cyclones in the Indian Ocean &amp;amp; Western Pacific&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-02-23T02:19:27.220" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4442" PostTypeId="1" AcceptedAnswerId="4446" CreationDate="2015-02-24T04:13:18.480" Score="8" ViewCount="3246" Body="&lt;p&gt;I am slightly confused as to how the following statement is true:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the density of the Earth’s atmosphere decreases, the average atmospheric surface pressure remains the same&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As dictated by the equation $P = \rho R_mT$, where P is pressure ρ is density, T is temperature, and Rm is the univeral gas constant divided by the molar mass, there should be a relationship between density and pressure. What is incorrect about my understanding of fundamental concepts?&lt;/p&gt;&#xA;" OwnerUserId="2604" LastActivityDate="2015-02-24T13:53:03.457" Title="Relationship between atmospheric density and atmospheric pressure?" Tags="|barometric-pressure|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4443" PostTypeId="2" ParentId="4431" CreationDate="2015-02-24T05:45:06.407" Score="4" Body="&lt;p&gt;Fine answers above. I think a historian of science would propose the &quot;psychology of scientists&quot; and the &quot;sociology of scientific institutions&quot; had a greater contribution to the controversy than any question about the veracity of the observations. You may be interested in viewing this interview with the science historian William Glen about &lt;a href=&quot;https://m.youtube.com/watch?v=u7JNssOvy14&quot; rel=&quot;nofollow&quot;&gt;PARADIGM INERTIA&lt;/a&gt;. His book about the history of plate tectonics (&lt;a href=&quot;http://books.google.com.br/books/about/The_Road_to_Jaramillo.html?hl=pt-BR&amp;amp;id=SNdQN0ZK_14C&quot; rel=&quot;nofollow&quot;&gt;The Road to Jaramillo&lt;/a&gt;) is based on direct interviews.    &lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2015-02-24T05:45:06.407" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4444" PostTypeId="2" ParentId="4271" CreationDate="2015-02-24T08:38:59.873" Score="2" Body="&lt;p&gt;From reading the literature on the subject, my impression is that we don't know that much on the subject, primarily due to a scarcity of measurements. My understanding is that the first and only year-long time-series was made at the Drake Passage in 1979 (e. g. &lt;strong&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0485%281985%29015%3C0810%3AVTOTAC%3E2.0.CO%3B2&quot; rel=&quot;nofollow&quot;&gt;Whitworth &amp;amp; Peterson, 1985&lt;/a&gt;&lt;/strong&gt;) by the ISOS programme (International Southern Ocean Studies). In addition to that NOAA's WOCE (World Ocean Circulation Experiment) added yearly data from 1990 to 2002.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &lt;strong&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2000JC900107/abstract&quot; rel=&quot;nofollow&quot;&gt;Rintoul &amp;amp; Sokolov 2001&lt;/a&gt;&lt;/strong&gt; and &lt;strong&gt;&lt;a href=&quot;http://epic.awi.de/2649/1/Rin8888b.pdf&quot; rel=&quot;nofollow&quot;&gt;Rintoul et al. 2001&lt;/a&gt;&lt;/strong&gt;, most of the variability south of Tasmania is due to changes in currents north of the ACC itself. &#xA;&lt;strong&gt;&lt;a href=&quot;http://dx.doi.org/10.1029/2001JC001147&quot; rel=&quot;nofollow&quot;&gt;Cunningham et al. 2003&lt;/a&gt;&lt;/strong&gt; show that the moderate interannual variation in baroclinic transport they observed seem to be coeval with variations in the location of the Polar Front (it moves north or south on a 90km range). But overall the variability seems to be relatively low, and the ACC relatively steady.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;a href=&quot;http://www.ccpo.odu.edu/~klinck/Reprints/PDF/whiteNature96.pdf&quot; rel=&quot;nofollow&quot;&gt;White &amp;amp; Peterson, 1996&lt;/a&gt;&lt;/strong&gt; showed an interesting phenomenon that they called the Antarctic Circumpolar Wave: it is a &quot;wave&quot; in the ACC circling the globe in ca. 8 yrs with a period of 4yrs at any location and it is defined by anomalies in sea-suface temperature, sea-level pressure and sea-ice extent. However no evidence for corresponding anomalies in volume transport was showed, to my knowledge. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, to summarize, as far as I can see:  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;not enough data for seasonal trends (only one yearlong time-series);&lt;/li&gt;&#xA;&lt;li&gt;some interannual variability (possibly as a consequence of variabilities in other water masses); &lt;/li&gt;&#xA;&lt;li&gt;not enough data to study decadal variation.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2015-02-24T09:19:04.620" LastActivityDate="2015-02-24T09:19:04.620" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4445" PostTypeId="1" AcceptedAnswerId="4447" CreationDate="2015-02-24T09:35:01.013" Score="11" ViewCount="3177" Body="&lt;p&gt;This question is, in part, inspired from the 1997 Hollywood movie &lt;a href=&quot;http://www.imdb.com/title/tt0120461/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Volcano&lt;/a&gt;, where a fictional volcano erupted out of the La Brea Tar Pits in Los Angeles. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://geology.com/articles/san-andreas-fault.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;San Andreas Fault&lt;/a&gt; is a transform fault plate boundary (see image below):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/w9odS.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image from the &lt;a href=&quot;http://earthquake.usgs.gov/learn/glossary/?term=transform%20fault&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS Glossary entry for transform faults&lt;/a&gt;, with a definition:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A transform fault is a special variety of strike-slip fault that accommodates relative horizontal slip between other tectonic elements, such as oceanic crustal plates.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A specific type of transform fault is a 'leaky transform fault', which according to a source used on its &lt;a href=&quot;http://en.wikipedia.org/wiki/Leaky_transform_fault&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia page&lt;/a&gt; describes the tectonic movement at this type of faulting as being:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In addition to the regular strike-slip motion observed at transform boundaries, an oblique extensional component is present, resulting in motion of the plates that is not parallel to the plate boundary.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Illustrated below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Z3VGP.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is there any evidence that oblique tectonic movement occurs along the San Andreas Fault?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Hence, is a San Andreas volcano possible?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-02-24T10:33:50.080" LastActivityDate="2015-02-24T19:05:05.390" Title="Is a San Andreas volcano possible?" Tags="|volcanology|tectonics|transform-fault|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4446" PostTypeId="2" ParentId="4442" CreationDate="2015-02-24T12:49:28.993" Score="5" Body="&lt;p&gt;There are two fundamental gas laws that need to be understood:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Boyle's Law which states     ${P_1.V_1 = P_2.V_2}$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From this formula if volume increases pressure decreases and vice versa&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second law is Charles's Law which states ${V_1/V_2 = T_1/T_2}$   or    ${V_1/T_1 = V_2/T_2}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This law states that if the temperature increases there must be a corresponding increase in volume of the gas and vice versa. Another way of looking at it is if the volume drops so must the temperature and vice versa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ideal gas law that you mention in your question can be also be written as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;${PV = mRT}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;P is pressure,&lt;/li&gt;&#xA;&lt;li&gt;V is volume&lt;/li&gt;&#xA;&lt;li&gt;m is mass&lt;/li&gt;&#xA;&lt;li&gt;R is the universal gas constant&lt;/li&gt;&#xA;&lt;li&gt;T is temperature&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Now, density, ${ρ = m/V}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which leads to the equation you used:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;${P = ρRT}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the primary ways the atmosphere changes is via changes in temperature. The atmosphere on the side of the Earth facing the Sun warms up, while the atmosphere of the other side of the Earth cools.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to Charles's Law, for the side facing the Sun, the increase in temperature will cause the volume to increase. An increase in volume will reduce the density, because mass doesn't change. With an increase in temperature and a decrease in density the pressure will remain unchanged.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2015-02-24T13:53:03.457" LastActivityDate="2015-02-24T13:53:03.457" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4447" PostTypeId="2" ParentId="4445" CreationDate="2015-02-24T13:58:22.180" Score="10" Body="&lt;p&gt;Yes. In fact there are already volcanos associated with the San Andreas fault system. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Neenach_Volcano&quot; rel=&quot;nofollow noreferrer&quot;&gt;Neenach&lt;/a&gt; is an extinct Miocene volcano split in half by the San Andreas fault. &lt;a href=&quot;https://twitter.com/geotripper&quot; rel=&quot;nofollow noreferrer&quot;&gt;Garry Hayes&lt;/a&gt; wrote a nice blog post about this volcano system: &lt;em&gt;&lt;a href=&quot;http://geotripper.blogspot.ca/2009/11/volcano-sundered-field-trip-along-san.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;A Volcano Sundered: A Field Trip Along the San Andreas Fault&lt;/a&gt;&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you'll allow some latitude in what counts as 'a San Andreas volcano', then there is active volcanism too. &lt;a href=&quot;http://en.wikipedia.org/wiki/Salton_Buttes&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Salton Buttes&lt;/a&gt; are a group of rhyolitic volcanos in the &lt;a href=&quot;http://en.wikipedia.org/wiki/Brawley_Seismic_Zone&quot; rel=&quot;nofollow noreferrer&quot;&gt;Brawley Seismic Zone&lt;/a&gt;, a set of oblique transform faults — actually in the axis of the active Gulf of California rift — on the south-east shore of the Salton Sea. You can see them in this Google Maps image (on the right; the big fields are 800 m across):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JVTrS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JVTrS.jpg&quot; alt=&quot;The Imperial Valley faults and the Salton Buttes&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Space Shuttle photo (left) of the Imperial Valley &lt;a href=&quot;http://earthquake.usgs.gov/research/salton/&quot; rel=&quot;nofollow noreferrer&quot;&gt;annotated by the USGS&lt;/a&gt; shows the relationship between the San Andreas fault, about 5 km from the volcanos, the Brawley Seismic Zone (BSZ), and the Imperial Fault to the south. At this scale, it's essentially one big fault system.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2015-02-24T19:05:05.390" LastActivityDate="2015-02-24T19:05:05.390" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4448" PostTypeId="2" ParentId="4431" CreationDate="2015-02-24T21:14:10.247" Score="10" Body="&lt;p&gt;I'm a bit late noticing this question, but if the OP is interested, here are a few additional thoughts which I hope may compliment the excellent answers already produced.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The distinction has already been made, above, between Wegener's 1920s &lt;strong&gt;Continental Drift&lt;/strong&gt; (he actually called it Continental &lt;em&gt;Displacement&lt;/em&gt;, the more whimsical term was created later by others to disparage Wegener's idea) and &lt;strong&gt;Plate Tectonics&lt;/strong&gt; which was developed 50 years ago, during the mid-1960s. It took several years for the plate tectonics model to be accepted, but as far as 'revolutionary' scientific theories are concerned, it actually caught on relatively quickly. Marie Tharp discovered mid-ocean rifts (1956); Harry Hess explained how they work and invoked the idea of subduction zones (1961); Morley, Vine, and Matthews proved seafloor spreading by using paleomagnetism (1963); Tuzo Wilson proposed hot spots and transform faults (1963); Isacks, Oliver, and Sykes mapped a subduction zone with seismic (1967); Jason Morgan divided the planet into plates (1968). Of course many others were also involved, but by 1968 only a few stubborn holdouts opposed plate tectonics theory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;To the point of the original question:&lt;/strong&gt; It took massive paleomagnetic, seismic, and thermal readings to convince most geologists that the crust moves laterally. It took a while before technology reached a level to prove tectonics. Further – and this is important – scientific theories need to be testable and measurable. With advanced technology, it became possible to predict plate movement and with accurate measurement (especially GPS), it finally became indisputable that the crust is moving in the ways the theory predicted. &lt;/p&gt;&#xA;" OwnerUserId="2487" LastActivityDate="2015-02-24T21:14:10.247" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4449" PostTypeId="1" AcceptedAnswerId="4559" CreationDate="2015-02-25T03:56:09.960" Score="15" ViewCount="2648" Body="&lt;p&gt;A &quot;meddy&quot; is usually described as a Mediterranean Water eddy. While many &lt;a href=&quot;http://dx.doi.org/10.1016/0967-0637(95)00045-8&quot;&gt;meddies&lt;/a&gt; have been &lt;a href=&quot;http://dx.doi.org/10.1016/S0079-6611(99)00053-1&quot;&gt;observed in recent years&lt;/a&gt;, I would want to know what are the common characteristics of such features (temperature, salinity, depth, lifespan)? What are the conditions that cause the formation of meddies? How are they preserved for so long as they may last for about 2 years and cover distances up to one thousand kilometers?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="6129" LastEditDate="2020-05-08T10:24:18.563" LastActivityDate="2020-05-08T13:48:27.670" Title="About meddies: what are they? How do they form? How are they maintained?" Tags="|oceanography|atlantic|mediterranean|eddies|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4450" PostTypeId="2" ParentId="2813" CreationDate="2015-02-25T08:32:21.587" Score="10" Body="&lt;p&gt;I don't think there can be &quot;the single standard&quot; for a range of technical and organisational reasons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Probably the biggest thing to note is that different formats serve different purposes. For example, comparing WFS, WMS and WCS. WFS is a feature concept - the sort of data you might get as observations from a set of irregularly distributed sites (e.g. automated weather stations at airports).  WMS is a picture (e.g. PNG image or JPEG) - the sort of data you might get as an IR image from a satellite, or some particular styling of a gridded forecast such as wave heights (turned into colour bands). WCS is a coverage (so no particular visual representation) - in the gridded forecast of wave heights example, it would be a floating point number of the height (average, peak, whatever is defined) for that &quot;grid area&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that these OGC protocols weren't really designed to handle multiple parameters at a time, nor were they designed to handle data represented in more than two dimensions at a time (e.g. you can ask for an elevation and a time, but you can't ask for multiple elevations and times in a single output without some custom (i.e. not standard) approach.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So you'll see observations and forecasts in specialist formats (like BUFR, GRIB and NetCDF). Those formats can be transmitted (e.g. raw files), but they're also able to be subsetted. THREDDS is a particularly good tool for this purpose. Note that GRIB and NetCDF have some overlap in scope. There are also multiple versions of GRIB, and there are non-standard parts to GRIB (e.g. forecast centre specific tables). Adding new standards &lt;a href=&quot;http://xkcd.com/927/&quot;&gt;doesn't help&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Changing formats isn't easy - there are often massive collections of data and complex tools (like numerical forecasting models) that need to be updated or reworked to handle new formats. Not everyone can do that (e.g. for financial reasons, or organisational expertise reasons, or some programmatic reason like there is already another upgrade going on) at the same time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So you can expect to need to handle lots of formats for a long time to come.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have options and need to exchange data, I'd start with NetCDF, mainly because it has a lot of pretty good tools.&lt;/p&gt;&#xA;" OwnerUserId="2574" LastActivityDate="2015-02-25T08:32:21.587" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4451" PostTypeId="2" ParentId="4426" CreationDate="2015-02-25T15:38:01.330" Score="9" Body="&lt;p&gt;Let us state the obvious reasons first:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Warm SSTs along the Timor Sea as well along the Queensland coast favour the formation of Tropical Cyclones - &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following two URLs show the SSTs along the Northern as well as Eastern Coast of Australia for the referenced periods. &#xA;a) &lt;a href=&quot;http://earth.nullschool.net/#2015/02/15/2100Z/ocean/primary/waves/overlay=sea_surface_temp/orthographic=136.27,-24.99,512&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://earth.nullschool.net/#2015/02/15/2100Z/ocean/primary/waves/overlay=sea_surface_temp/orthographic=136.27,-24.99,512&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;b) &lt;a href=&quot;http://earth.nullschool.net/#2015/02/20/2100Z/ocean/primary/waves/overlay=sea_surface_temp/orthographic=136.27,-24.99,512&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://earth.nullschool.net/#2015/02/20/2100Z/ocean/primary/waves/overlay=sea_surface_temp/orthographic=136.27,-24.99,512&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The threshold SST required for tropical cyclogenesis is 26.5 C as shown in &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/JCLI-D-10-05006.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Threshold Sea Surface Temperature Condition for Tropical Cyclogenesis&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The role of equatorial waves in tropical cyclongenesis and in this case interaction of equatorial waves with the monsoon trough. Results of filtered OLR as shown in the image below shows the presence of an Equatorial Rossby Wave over those regions and the presence of blue shades indicates negative OLR (enhanced convection).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/XU7JZ.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source - &lt;a href=&quot;https://ncics.org/portfolio/monitor/mjo/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tropical Wave Monitoring&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This reference &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/2009MWR3115.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Role of Equatorial Rossby Waves in Tropical Cyclogenesis. Part II: IdealizedSimulations in a Monsoon Trough Environment&lt;/a&gt; clearly states that &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot; When just the MT is simulated without the ER wave anomaly fields,&#xA;  the MT remains quasi-steady and TC genesis does not occur. It is only&#xA;  when the ER wave is imposed on the MT that TC genesis is initiated.&#xA;  The results imply that the ER wave–MT interactions produce more TCs&#xA;  than would otherwise occur if no such interactions took place.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;&lt;p&gt;A question that can be raised  is that  we do know that presence of MJO also promotes tropical cyclongenesis as shown in this reference &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/2009JAS3101.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Diagnosis of the MJO Modulation of Tropical CyclogenesisUsing an Empirical Index&lt;/a&gt;. So how can does one state unequivocally that it is a Equatorial Rossby Wave and not the MJO's interaction with the MT that favours tropical cyclogenesis ? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we look at the strength of the MJO signal during and after the formation of TC Lam &amp;amp; Maria &lt;/p&gt;&#xA;&#xA;&lt;p&gt;as shown in these set of images &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/7qc3c.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The amplitude of MJO signal is currently weak (less than 1 being present inside the circle) and is unlikely to be a significant contributor to the formation of tropical cyclones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This conclusion can be enhanced by looking at the filtered OLR contributions from MJO - &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/jyRP7.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The presence of positive OLR(in yellow over the Northern/Eastern part of Australia indicating suppressed convection. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Both the MJO as well as tropical waves favour the formation of twin cyclones as shown by references &lt;a href=&quot;http://schubert.atmos.colostate.edu/publications/refereed/nietoetal1996_dynamical.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dynamical Aspects Of Twin Tropical cyclones  Associated with the Madden Julien Oscillation &lt;/a&gt; and &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/2008MWR2541.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;A Case Study of an Outbreak of Twin Tropical Cyclones&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Update&lt;/strong&gt;&#xA;In an earlier question that I had asked &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2803/relation-between-direction-of-shear-and-cyclone-formation&quot;&gt;Relation between direction of shear and cyclone formation&lt;/a&gt; one can clearly see a working example of easterly shear favoring the formation of tropical cyclone. So easterly shear as shown in the map below is defined as the difference in the zonal winds at two different pressure levels (850 hPa and 200 hPa). Since by convention easterly winds are noted to be negative increasing positive values of shear is easterly shear(as one travels vertically) and the opposite is westerly shear. The following shear plot is a mean of several days and one can see the easterly shear over the Australian regions where the cyclone formation took place.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$zonal\_shear = U_{850} - U_{200} $&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data is from NCAR NCEP reanalysis.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ej2pR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ej2pR.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-02-24T13:48:21.703" LastActivityDate="2019-02-24T13:48:21.703" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="4452" PostTypeId="1" AcceptedAnswerId="4457" CreationDate="2015-02-25T21:28:01.007" Score="15" ViewCount="2816" Body="&lt;p&gt;A set of banded clouds can be seen in MODIS imagery during several days in January and February over the Gulf of Maine. They tend to occur with very cold winds from the NW following storms.&#xA;&lt;img src=&quot;https://i.stack.imgur.com/DDF01.jpg&quot; alt=&quot;MODIS 06FEB2015&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are several &lt;a href=&quot;https://earthdata.nasa.gov/labs/worldview/?p=geographic&amp;amp;l=MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels(hidden),Reference_Features(hidden),Coastlines&amp;amp;t=2015-02-24&amp;amp;v=-87.826942092556,19.726151953444,-44.057410842556,51.894120703444&quot; rel=&quot;noreferrer&quot;&gt;similar examples&lt;/a&gt;: 17 January and 6, 20 and 24 February&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What causes these features? Why are they of that size?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="6298" LastEditDate="2022-02-06T17:22:44.900" LastActivityDate="2022-02-06T17:22:44.900" Title="What causes these banded clouds?" Tags="|meteorology|atmosphere|clouds|satellites|satellite-oddities|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4453" PostTypeId="2" ParentId="4452" CreationDate="2015-02-25T22:49:20.883" Score="4" Body="&lt;p&gt;These features are internal gravity waves (IGW) and are characterized by alternating areas of upwards and downwards movement of air parcels. They propagate on a sharp density interface between a relatively dry layer ambient air above and a layer of sea water laden air below. When the moist air rises the cloud is formed above the condensation level and eventually evaporates at the trailing edge of the wave. In other words, the cloud regions in the photograph represent the wave crest and the &quot;empty space&quot; in between is the wave trough.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An important requirement for IGWs is a stably stratified atmosphere, and specifically for these waves shown in the photograph, a relatively sharp interface. If the interface thickness is larger the continuous variation of density with height adds the possibility of vertical propagation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;IGWs can be generated by a variety of phenomena, ranging from orographic to non-orographic mechanisms. The former is mentioned in the comments and is relatively intuitive and easy to understand. In the latter case it is not so clear, there are several proposed mechanisms that may contribute to the generation of IGWs, for example, Bühler et al (1999) considered the generation of internal waves by an localized unstable shear layer at the top of the jet stream. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, three convective generation mechanisms are typically considered (Song et al, 2003):&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Thermal Forcing:&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;convective clouds are regarded as thermal forcings that generate&#xA;  gravity waves (nonstationary or stationary waves relative to the&#xA;  thermal forcing) in a stably stratified environment.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;Obstacle: &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;convective clouds are considered obstacles to the flow, and gravity&#xA;  waves are generated when the flow is subsequently blocked.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;Mechanical oscillator: &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;strong convective updrafts in convective storms stimulate the stable&#xA;  stratosphere and generate gravity waves above clouds. Convective cells&#xA;  acting as mechanical oscillators, as well as a nonsteady diabatic&#xA;  forcing, can generate gravity waves even under zero background wind&#xA;  relative to the convective cells&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0469%281999%29056%3C3749:OSGGWT%3E2.0.CO%3B2&quot; rel=&quot;nofollow&quot;&gt;Oliver Bühler, Michael E. McIntyre, and John F. Scinocca, 1999: On Shear-Generated Gravity Waves that Reach the Mesosphere. Part I: Wave Generation. J. Atmos. Sci., 56, 3749–3763.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0469%282003%29060%3C1960:GMOCFI%3E2.0.CO%3B2&quot; rel=&quot;nofollow&quot;&gt;In-Sun Song, Hye-Yeong Chun, and Todd P. Lane, 2003: Generation Mechanisms of Convectively Forced Internal Gravity Waves and Their Propagation to the Stratosphere. J. Atmos. Sci., 60, 1960–1980.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2015-02-25T22:54:56.333" LastActivityDate="2015-02-25T22:54:56.333" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4454" PostTypeId="2" ParentId="340" CreationDate="2015-02-26T05:52:19.620" Score="2" Body="&lt;p&gt;Straight rivers usually occurs on igneous or metamorphic rocks and rugged relief.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meanders rivers usually occurs in plain surfaces . Plain surfaces usually are covered by sedimentary rocks or sediments (easiest to erode). In a curve, the water is stronger in the open side and tends to erode, in the other margin it tends to accumulate sediment.&lt;/p&gt;&#xA;" OwnerUserId="2609" LastActivityDate="2015-02-26T05:52:19.620" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4455" PostTypeId="2" ParentId="4315" CreationDate="2015-02-26T06:02:25.207" Score="3" Body="&lt;p&gt;The water has an uncommon property: at 4°C it's heavier(most dense) that at 0°C. This makes ice floats on surface and ice is a good thermical isolator, preventing the water below freezing.&lt;/p&gt;&#xA;" OwnerUserId="2609" LastEditorDisplayName="user889" LastEditDate="2015-02-26T06:49:24.000" LastActivityDate="2015-02-26T06:49:24.000" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4456" PostTypeId="2" ParentId="773" CreationDate="2015-02-26T06:45:55.807" Score="3" Body="&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;There is some studies pointing to a bigger activity of tectonism in Mid-Atlantic Ridges on ice ages. With more water freezed in south and north poles and less water in the ocean, the weight of water over South America plate(and others) are lower and the tectonics plates will be more active.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;In low rain periods, less chemical intemperism will happen(main source of sediments).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;These factors and others more should modify the proportion of rock kinds.&lt;/p&gt;&#xA;" OwnerUserId="2609" LastActivityDate="2015-02-26T06:45:55.807" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4457" PostTypeId="2" ParentId="4452" CreationDate="2015-02-26T06:47:55.290" Score="14" Body="&lt;p&gt;These are most certainly &lt;a href=&quot;http://en.wikipedia.org/wiki/Horizontal_convective_rolls&quot;&gt;boundary layer rolls&lt;/a&gt; and &lt;em&gt;not&lt;/em&gt; gravity waves. While there exists a visual similarity between the two phenomena, and both may exist in similar atmospheric conditions, they can be distinguished by two key characteristics: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Unlike gravity waves, which develop in the downwave direction (perpendicular to the crest), boundary layer rolls develop downwind (parallel to the apparent &quot;crest&quot;);&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Unlike gravity waves, whose crest propagates with intrinsic phase speed (related to interfacial density difference and gravitational acceleration) and whose energy propagates with intrinsic group velocity, the large-scale structure of boundary layer rolls is quasi-stationary.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Despite the visual resemblence between gravity waves and boundary layer rolls and possible interactions reported in the literature, it is my opinion that stating that boundary layer rolls are a form of gravity waves is incorrect and misleading.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is clear based on the satellite picture that the wind is northwesterly because of the distance from land that the convection occurs over the ocean, which is approximately 50 km from the coast uniformly in the SW-NE direction. As the cold and dry air moves over (relatively) warm water, air rises and saturates with water vapor, forming clouds downwind from the coast. For these to be gravity waves, wind would have to be perpendicular to the wave crest, i.e.  in the SW-NE direction, which is not the case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now that we agree that the wind is northwesterly, we see that the convective lines, the so-called &quot;cloud streets&quot;, are aligned with the wind. They are long rolls of counter-rotating air that stretch the depth of the atmospheric boundary layer in height (~1 km) and are of width between 1 and 10 km. Water vapor condensation and cloud formation happens on the upward side of the roll, and evaporation happens on the downward side of the roll. Notice that in this particular example, they start off very thin, and become wider downwind. While these rolls are still not very well understood, the main mechanism for formation is likely to be a combination of rotation and friction (Ekman spirals) in presence of thermally unstable bottom boundary layer, and stable boundary layer cap, thus constraining the circulation into organized cells. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A review paper on boundary layer rolls by Etling and Brown (1993) can be found &lt;a href=&quot;http://link.springer.com/article/10.1007%2FBF00705527&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2015-02-26T21:44:23.537" LastActivityDate="2015-02-26T21:44:23.537" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="4458" PostTypeId="2" ParentId="2393" CreationDate="2015-02-26T07:06:38.227" Score="6" Body="&lt;p&gt;Gold has primary origin in hydrothermal veins and contact metamorphic deposits and pegmatites. &#xA;Also occurs in placer deposits of secondary origin. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is more easily found in veins that is related to igneous rocks rich in silica. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main sources of gold are in hydrothermal quartz veins with pyrite and other sulfides. Gold is mechanically mixed with sulfides and not by chemical substitution. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In most of the gold grain is so finely disseminated that its presence can only be detected with microscopic techniques. Plenty of 0.004 ppm in the Earth's crust.&lt;/p&gt;&#xA;" OwnerUserId="2609" LastActivityDate="2015-02-26T07:06:38.227" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4459" PostTypeId="2" ParentId="4366" CreationDate="2015-02-27T04:21:39.280" Score="3" Body="&lt;p&gt;I suspect that the image is due to 'bubbles' of hotter air in the valleys inter dunes. They have a different IOR (Index Of Refraction) then the surrounding areas and the light path deviates from the 'straigth' line trajectory. In addition the light path length between the bottom of the valley and the equi-IOR plane above is larger than the one from the top of the hill to the same plane and the amount of deviation is proportional to the path length.  This atmospheric effect can appear in the absence of wind and in hot days.&lt;br&gt;&#xA;The center of the valleys are hotter then the top of the hills because light is reradiated from the surfaces and more surface amount is pointing to the central volume, the same as with parabolic antennas. &lt;/p&gt;&#xA;" OwnerUserId="2613" LastActivityDate="2015-02-27T04:21:39.280" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4460" PostTypeId="2" ParentId="2176" CreationDate="2015-02-27T05:04:42.527" Score="-3" Body="&lt;p&gt;&lt;strong&gt;Facts&lt;/strong&gt;:&lt;br&gt;&#xA;The strip along the equator receives more solar radiation and hence there is more moisture in the air. This reduces the difference between maximum and minimum temperatures. As there exist more clouds the maximum temperatures are not as high as in other &lt;em&gt;temperate&lt;/em&gt; regions of the Earth.&lt;br&gt;&#xA;&lt;strong&gt;An &lt;em&gt;If&lt;/em&gt;:&lt;/strong&gt;&lt;br&gt;&#xA;If there is global warming then the equatorial region becomes larger and, in the extreme limit all the earth would have equatorial climate.&lt;br&gt;&#xA;&lt;strong&gt;Then:&lt;/strong&gt;&lt;br&gt;&#xA;With global cooling the process would be the reverse:&#xA;The equatorial area reduces, the air is dryer, increase of the contrast between maximum and minimum temperatures (diurnal and annual), increase the erosion and greater intensity of local winds.&#xA;So, in this global cooling scenario deserts get bigger.&#xA;Because the maximum temperatures are increasing, most people and also many scientists, get the wrong impression that we are living in a global warming cycle.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;About the Sahel:&lt;br&gt;&#xA;Most of the hot deserts extend from latitude 15 to 35º degrees because they depend on the &lt;a href=&quot;http://www.english-online.at/geography/deserts/deserts.htm&quot; rel=&quot;nofollow&quot;&gt;trade winds&lt;/a&gt;. As explained above the long term evolution of the equatorial zone should be shrinking from a global cooling viewpoint and then the &lt;a href=&quot;http://montessorimuddle.org/wp-content/uploads/2011/04/deserts-id.png&quot; rel=&quot;nofollow&quot;&gt;desert land strips&lt;/a&gt; will approach the equator invading the Sahel and the south of Angola.   &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;EDIT ADD:&lt;br&gt;&#xA;after 4 downvotes without any explanation on physics I will copy/past from  ENCYCLOPEDIA of PALEOCLIMATOLOGY AND ANCIENT ENVIRONMENTS - ARID CLIMATES AND INDICATORS &lt;/p&gt;&#xA;&#xA;&lt;p&gt;where you can find what I said above:  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Pleistocene accentuation of aridity&lt;br&gt;&#xA;  Although deserts may have existed before the Pleistocene, &lt;strong&gt;there is evidence that aridity was intensified&#xA;  in many regions in the late Pliocene and Pleistocene&lt;/strong&gt;. It appears to&#xA;  have become a prominent feature of the Sahara in the late Cenozoic,&#xA;  &lt;strong&gt;partly because of the cooling of the oceans and partly because the&#xA;  buildup of ice caps created a steeper temperature gradient between the&#xA;  Equator and the Poles. This in turn led to an increase in trade-wind&#xA;  velocities and in their ability to mobilize dust and sand. DeMenocal&#xA;  (1995)&lt;/strong&gt; recognized a great acceleration in dust loadings in ocean cores&#xA;  off the Sahara and Arabia after 2.8 Ma, and attributed these to a&#xA;  decrease in sea surface temperatures associated with the initia- tion&#xA;  of extensive Northern Hemisphere glaciation. Likewise, loess&#xA;  deposition became more intense in China after around&#xA;  2.5 Ma ago and eolian activity in the American High Plains dates back beyond 1.4 million y BP . The study of sediments from the central&#xA;  parts of the North Pacific suggest that eolian processes (dust&#xA;  deposition) became more important in the late Tertiary, accelerating&#xA;  greatly between 7 and 3 Ma (Leinen and Heath, 1981). It was around 2.5&#xA;  Ma ago that the most dramatic increase in eolian sedimentation&#xA;  occurred – an increase that accompanied the onset of Northern&#xA;  Hemisphere glaciation. In Arabia, humid conditions in the late&#xA;  Tertiary caused deep weathering and fluvial incision of lava flows&#xA;  dated to 3.5 Ma. Such signs are absent in early Pleistocene flows&#xA;  (Hötzl et al., 1978).&lt;br&gt;&#xA;  Environmental fluctuations within the Pleistocene&lt;br&gt;&#xA;  &lt;strong&gt;All deserts show the impact of Pleistocene climatic changes&lt;/strong&gt;; no deserts were immune. On the one hand, the deserts expanded&#xA;  from time to time, covering areas that are now wooded and forested. As&#xA;  a consequence, stabilized sand seas occur in areas where rainfall&#xA;  levels are currently in excess of 800 mm. &lt;strong&gt;A large tract of dead ergs&#xA;  occurs on the south side of the Sahara from Senegal in the west to&#xA;  Sudan in the east&lt;/strong&gt;, while in southern Africa the Mega-Kalahari extended&#xA;  into Angola, Zambia, Zimbabwe and the Congo Basin.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As seen, the Deserts are a very recent feature on Earth, which means that the temperature in the past was hotter (and less global winds).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm consistent with data in the above topic and in the new model here presented  (hoho it is vixra, do not read it, it is poison):  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://vixra.org/pdf/1412.0170v1.pdf&quot; rel=&quot;nofollow&quot;&gt;A Model of Past Earth’s Climate from Isotopic and Biologic Data and Its Relationship with Orbits’ Expansion&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first model of the past hot Earth’s climate consistently indicated by isotopic and biologic data is here established. This model, here named Evolving Climate Model (ECM), accurately matches a 3 Gy long compilation of isotope $^{18}O$ data. An important consequence of the model is the fast increase of oxygen atmospheric level between 2 and 1 Ga (Gy ago); this is a well-known but until now mysterious occurrence, the Great Oxygenation Event. A solution is presented for the two centuries old “dolomite problem” and new explanations arise for a number of long lasting problems, such as the origin of petroleum or of proto-continents. Differently from the usual climate scenarios, the ECM presents ideal conditions for the massive production of long organic molecules. Critical occurrences of life evolution, such as the Cambrian explosion, are explained and fitted by the ECM, exposing a previously unknown connection between the evolution of life and climate. The most likely cause for this hot past is the expansion of orbits; it is verified that this phenomenon can explain the ECM, the receding of the Moon and the water on early Mars for the same value of H0 = 48 km s-1 Mpc-1, which, if not a coincidence, is a non-negligible result. &lt;/p&gt;&#xA;" OwnerUserId="2613" LastEditorUserId="2613" LastEditDate="2015-09-14T19:36:32.607" LastActivityDate="2015-09-14T19:36:32.607" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4461" PostTypeId="2" ParentId="4425" CreationDate="2015-02-28T04:05:15.210" Score="-6" Body="&lt;p&gt;I will explore the answer admitting that the Earth's temperature in the ancient past was much higher than we now assume as possible. The current standard model is the 'Snowball Earth' which leaves many unsolved problems - see 'Faint Young Sun Paradox'.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will assume that the total amount of $\ce{H_2O}$, $\ce{CO_2}$, $\ce{O_2}$ is substantially constant throughout the entire history of the earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All the water of the oceans would stay in the atmosphere layer   provided the temperature was high enough. The percentage of oxygen would be $\approx 0$ because it would be masked by the massive presence of $\ce{H_2O}$.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Later, when the temperature dropped, the water has migrated to the ocean floor and the percentage of $\ce{O}$ exploded to current levels. This fact is called the 'Great Oxygenation Event' and it is not very well understood under the standard model. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;About the &lt;strong&gt;free Oxygen origin&lt;/strong&gt;: (Copy / Paste)  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;There are two known natural ways of producing oxygen: by UV&#xA;  dissociation of H2O and by photosynthesis. In the ECM, the former&#xA;  process was initially much more efficient than at present because of&#xA;  the huge amount of water vapour and of the greater intensity of UV&#xA;  radiation occurring then. The biological production of oxygen would&#xA;  have been important during the Archean, which ended at&#xA;  2.5 Ga, therefore earlier than the GOE. The usual approach is to consider that the biologically produced oxygen was first combined with&#xA;  dissolved iron in oceans and only significantly released to the&#xA;  atmosphere later – a way to explain the delay between the presumed&#xA;  time of the biological production of oxygen and the rise of its&#xA;  atmospheric level. Here, there is no need to consider a delay – the&#xA;  biologically produced oxygen was dissolved in water and absorbed by&#xA;  the huge atmosphere without significantly changing its composition;&#xA;  the oxygen level increased only when the atmosphere significantly&#xA;  decreased due to the condensation of water vapour. One can now&#xA;  consider that oxygen was produced in large amounts since the&#xA;  beginning, first from UV dissociation, at a rate that decreased over&#xA;  time, and very soon followed by biological production. In this case,&#xA;  there was an important amount of free oxygen in the atmosphere long&#xA;  before its atmospheric level started to increase significantly; and&#xA;  some potential evidences of it can be identified (for a review see&#xA;  Yamaguchi, 2005).&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;ECM&lt;/strong&gt; stands for &lt;strong&gt;Evolving Climate Model&lt;/strong&gt; where this new concept was brought to life in a formal document (if you wish to explore further you can follow the 2nd link in my profile, not peer-reviewed)  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT add:&lt;br&gt;&#xA;Although no one wants to peer review the document of ECM,(*) its graph on fig.9 provides modeled data that is aligned with the most recent measurement of Oxigen.&lt;br&gt;&#xA;Measures goes against all of the accepted models ( 5 times more Oxigen at 815Ma), as seen on fig 4 on this news&lt;br&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/P0MPn.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/P0MPn.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;a href=&quot;http://motherboard.vice.com/en_uk/read/scientists-release-air-that-has-been-trapped-for-800-million-years&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://motherboard.vice.com/en_uk/read/scientists-release-air-that-has-been-trapped-for-800-million-years&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the contrary the Fig. 9 of ECM  &lt;a href=&quot;https://i.stack.imgur.com/xt8uK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xt8uK.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;Fig. 9. The variation of Oxygen volumetric ratio in the ECM1 due&#xA;to the variation of the size of the atmosphere, holding the&#xA;amount of Oxygen constant (thick blue line). The grey lines&#xA;represent the limits for the oxygen volumetric ratio (partial&#xA;pressure in the atmosphere) estimated in Holland (2006)  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;ECM is not peer-reviewed but it predicted the data to be seen (it is Data-reviewed) !   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(*) ECM is a creation of an engineer, and scientists assume that science is not for engineers.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;note: This new measurement enable to say: Oxygen first, Life second, rendering erroneous most of the answers one can find around.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why so many down votes (5) if it is notorious that none could find an error in the document?  &lt;/p&gt;&#xA;" OwnerUserId="2613" LastEditorUserId="2613" LastEditorDisplayName="user889" LastEditDate="2016-08-25T11:21:52.243" LastActivityDate="2016-08-25T11:21:52.243" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4462" PostTypeId="2" ParentId="4425" CreationDate="2015-02-28T08:51:12.100" Score="9" Body="&lt;p&gt;This is only a partial answer as it doesn't explain why the excess of O&lt;sub&gt;2&lt;/sub&gt; stayed but one thing you have to appreciate is the fact that aerobic respiration appeared almost half a billion years after photosynthesis, so we can't really say that photosynthesis and respiration have always balanced each other.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cyanobacteria (and with them photosynthesis) are believed to have appeared somewhen between 3 and 2.5Ga (e. g. &lt;strong&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0923250803002018&quot; rel=&quot;noreferrer&quot;&gt;Altermann &amp;amp; Kazmierczak 2003&lt;/a&gt;&lt;/strong&gt;, &lt;strong&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0016703703002096#&quot; rel=&quot;noreferrer&quot;&gt;Brocks et al. 2003&lt;/a&gt;&lt;/strong&gt;) while Mitochondria (and with them aerobic respiration) are thought to have evolved somewhen between 2 and 1.5Ga (see e. g. &lt;strong&gt;&lt;a href=&quot;http://www.hedgeslab.org/pubs/156.pdf&quot; rel=&quot;noreferrer&quot;&gt;Hedges et al. 2004&lt;/a&gt;&lt;/strong&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There was therefore at least half a billion year during which cyanobacteria were producing O&lt;sub&gt;2&lt;/sub&gt; with no one able to breathe it.&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2015-02-28T11:46:40.130" LastActivityDate="2015-02-28T11:46:40.130" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4463" PostTypeId="1" CreationDate="2015-02-28T22:52:15.470" Score="8" ViewCount="145" Body="&lt;p&gt;According to the San Diego State University (SDSU) webpage &lt;a href=&quot;http://www.geology.sdsu.edu/how_volcanoes_work/Unusual%20lava.html&quot;&gt;Unusual Lava Types&lt;/a&gt;, &lt;strong&gt;komatiite&lt;/strong&gt; is&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;ultramafic volcanic rocks, having very low silica contents (~40-45%) and very high $\ce{MgO}$ contents (~18%). These lavas are exceptional not only for their compositions, but also for their very old, restricted ages. These lavas have no modern analogs.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The vast majority of komatiite deposits, according to the SDSU webpage, are about 3 Ga or older in age, due to&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;These ancient lava flows erupted at a time when the Earth's internal heat was much greater than today, thus generating exceptionally hot, fluid lavas with calculated eruption temperatures in excess of 1,600 degrees C (2,900 degrees F).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, with many things in Science, there are exceptions - according to the SDSU webpage, &lt;a href=&quot;http://en.wikipedia.org/wiki/Gorgona_Island,_Colombia&quot;&gt;Gorgona Island, Colombia&lt;/a&gt; has komatiite deposits that are Cretaceous in age (around 90 Ma). The presence of young komatiite hints at higher temperatures at formation - something that has not been seen in any significant amount since the Archaean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What caused the high temperatures that resulted in the Cretaceous aged komatiite lavas of Gorgona Island, Colombia?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-02-28T23:20:51.277" LastActivityDate="2017-10-13T10:29:30.593" Title="What caused the high temperatures that resulted in the Cretaceous aged komatiite lavas of Gorgona Island, Colombia?" Tags="|volcanology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4466" PostTypeId="1" AcceptedAnswerId="4488" CreationDate="2015-03-01T09:53:14.100" Score="10" ViewCount="4968" Body="&lt;p&gt;The Great Artesian Basin in Australia covers 23% of the continent and contains 64,900 cubic kilometres of water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many years ago it was claimed on a TV science show I saw that some of the water in the basin comes from Papua New Guinea (PNG) via an underground conduit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it true that the Great Artesian Basin in Australia gets some of its water from PNG and how is the water transported from PNG to Australia under the Torres Strait?&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorDisplayName="user889" LastEditDate="2015-03-02T09:38:30.937" LastActivityDate="2019-06-10T20:47:11.930" Title="Source of water for the Great Artesian Basin in Australia" Tags="|hydrology|groundwater|" AnswerCount="3" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="4467" PostTypeId="1" AcceptedAnswerId="4549" CreationDate="2015-03-01T14:44:16.137" Score="8" ViewCount="415" Body="&lt;p&gt;I understand that volcanic ash plumes can only rise to great heights (e.g. 50km) with the help of some other processes, as the velocity of the material ejected isn't great enough to send it high into the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't understand how exactly these processes take place. I think that cooler, atmospheric gases are entrained towards the hotter, denser volcanic plume, then become heated and incorporated into the ash plume, causing it to become buoyant and to expand. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What causes the cool, atmospheric gas to move towards the plume? Is it due to the temperature differences between the plume and the atmosphere, or some kind of pressure difference? &lt;/p&gt;&#xA;" OwnerUserId="721" LastEditorDisplayName="user889" LastEditDate="2015-03-19T11:27:00.160" LastActivityDate="2015-03-19T17:55:18.577" Title="What causes the entrainment of atmospheric gases towards a volcanic ash/tephra plume?" Tags="|geophysics|atmosphere|volcanology|volcanic-hazard|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4468" PostTypeId="1" CreationDate="2015-03-02T16:06:41.013" Score="12" ViewCount="5278" Body="&lt;p&gt;On a recent, late-evening flight from New York City to San Fransisco, I was seated on the right side of the plane. We were flying over lake Michigan - about 2 hours into the flight. When we were over the mid-west I looked out of the window and could see these continuous flashes in the sky. At first I thought it was lightning, however this continued for almost 30 minutes or so and seemed to be silent too. What is this phenomenon?&lt;/p&gt;&#xA;" OwnerUserId="2544" LastEditorUserId="725" LastEditDate="2017-02-08T10:01:14.870" LastActivityDate="2017-02-08T10:01:14.870" Title="Weak flashes of light in the sky" Tags="|atmosphere|lightning|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4469" PostTypeId="2" ParentId="4468" CreationDate="2015-03-02T16:24:42.580" Score="15" Body="&lt;p&gt;You were most likely seeing lightning (to be sure, a date/time and your location would be necessary).  Lightning can be visible from quite a distance and storms can be incredibly active with lightning within the clouds and from cloud-to-cloud.  Given a large distance and being inside a (relatively) loud airplane cabin it is no surprise that you couldn't hear the thunder associated with the lightning flashes.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-03-02T16:24:42.580" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4470" PostTypeId="1" CreationDate="2015-03-02T16:34:49.637" Score="10" ViewCount="659" Body="&lt;p&gt;A recent article by &lt;a href=&quot;http://dx.doi.org/10.1002/2015GL063040&quot; rel=&quot;nofollow noreferrer&quot;&gt;Yu et al.&lt;/a&gt; estimated that 28 million tons of dust from the Sahara fall to the surface over the Amazon basin per year out of the 132 million tons that remain in the air when the dust reaches South America. The deposited dust is rich in phosphorus and contributes 22,000 tons of P per year, which is about the same amount lost from rain and flooding. The question is: how important is this phosphorus to the biological production of the Amazon basin? Also, considering &lt;a href=&quot;http://dx.doi.org/10.1002/2015GL063040&quot; rel=&quot;nofollow noreferrer&quot;&gt;Yu et al.&lt;/a&gt; reported very large interannual variability, do we expect to see any variability in the production at annual to decadal scales?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/62OVq.jpg&quot; alt=&quot;Sahara dust&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-03-06T11:08:46.383" Title="How important is Sahara dust for the Amazon?" Tags="|desert|atmospheric-dust|amazon|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4471" PostTypeId="2" ParentId="4468" CreationDate="2015-03-02T20:43:07.083" Score="6" Body="&lt;p&gt;While I wouldn't rule out that you were witnessing distant lightning lighting up the clouds below, or at some distance anyhow, there is also the possibility of the flashes being &lt;a href=&quot;http://Upper-atmospheric_lightning&quot;&gt;upper-atmospheric lightning&lt;/a&gt; such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Sprite_(lightning)&quot;&gt;Sprites&lt;/a&gt;. The half hour duration of the phenomena seems quite a long duration if we assume a plane in flight would cover somewhere about 300 miles in this time. So another possibility could be &lt;a href=&quot;https://en.wikipedia.org/wiki/St._Elmo%27s_fire&quot;&gt;St. Elmo's fire&lt;/a&gt; and another possibility would be wing condensation flashes over the wings, reflecting the light from inside the plane. &lt;a href=&quot;https://www.youtube.com/watch?v=N68rZZdhGvU&quot;&gt;A youtube video of the effect at take off in daylight&lt;/a&gt;. Or else possibly a cloud situation that reflected back the plane's own flashing exterior lights for this portion of the journey.&lt;/p&gt;&#xA;" OwnerUserId="140" LastActivityDate="2015-03-02T20:43:07.083" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4472" PostTypeId="2" ParentId="4405" CreationDate="2015-03-02T21:47:30.480" Score="4" Body="&lt;p&gt;I do not have access to the full-text, but the abstract of Giggenbach (1996)[1] suggests that &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The variability in the composition of volcanic gases accessible to sampling, therefore, is largely due to shallow processes, such as reequilibration in response to cooling and dilution by meteoric water, and interaction with fluids of associated hydrothermal systems.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The section &lt;strong&gt;Gas Compositions and Tectonic Setting&lt;/strong&gt; in [2], from Oregon State University has quite a nice table showing that the different volcanoes do seem to have different gas compositions, depending on where they are found and consequently what type of tectonic setting they occur in. I am not sure if these variations are actually significant though, not being a vulcanologist.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is certainly not a complete answer, but it does look like it might not be that easy to use the volatiles as a diagnostic feature. Hope that this helps somewhat....&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://link.springer.com/chapter/10.1007/978-3-642-80087-0_7&quot; rel=&quot;nofollow&quot;&gt;http://link.springer.com/chapter/10.1007/978-3-642-80087-0_7&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://volcano.oregonstate.edu/gas-compositions-and-tectonic-setting&quot; rel=&quot;nofollow&quot;&gt;http://volcano.oregonstate.edu/gas-compositions-and-tectonic-setting&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="2514" LastActivityDate="2015-03-02T21:47:30.480" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4473" PostTypeId="1" AcceptedAnswerId="4506" CreationDate="2015-03-03T02:56:28.450" Score="8" ViewCount="205" Body="&lt;p&gt;After looking at this question - &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4466/source-of-water-for-the-great-artesian-basin-in-australia&quot;&gt;Source of water for the Great Artesian Basin in Australia&lt;/a&gt; one would like to know whether there are any underwater rock conduits that transport fresh water across seas in the world. I have not come across any in my search, but maybe there does exist that I am not aware of. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2019-08-16T17:35:40.543" Title="Underwater rock conduit" Tags="|hydrology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4474" PostTypeId="1" CreationDate="2015-03-03T04:56:30.597" Score="9" ViewCount="168" Body="&lt;p&gt;My knowledge of science is very basic, but after some research I have some knowledge, but I am still not clear with so many things regarding to this earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have read &lt;a href=&quot;http://www.livescience.com/17619-lasers-measure-earth-rotation-wobble.html&quot;&gt;Laser's Measure the Earth's Rotation and Wobble&lt;/a&gt; but would appreciate it if anyone who knows science well, could explain how the rotation of the Earth is measured and how it is affected by the Chandler wobble and the annual wobble? &lt;/p&gt;&#xA;" OwnerUserId="2626" LastEditorUserId="2470" LastEditDate="2015-03-03T06:41:05.497" LastActivityDate="2015-03-03T19:37:39.147" Title="How to measure the cycles of earth moving/rotation?" Tags="|earth-history|earth-rotation|earth-observation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4476" PostTypeId="2" ParentId="4473" CreationDate="2015-03-03T12:41:52.233" Score="4" Body="&lt;p&gt;From a purely hypothetical point of view, it is very unlikely that a submerged aquifer could carry freshwater underneath a marine environment.  Salt water being more dense that fresh water would seep into the aquifer and displace the freshwater.  The saltwater intrusions into freshwater aquifers in coastal regions across the globe is proof of this behavior.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A possible but improbable scenario for your underwater rock conduit might be to have a sealed artesian aquifer with significant pressure gradient (perhaps limestone/dolomite bounded by shale) whose source is nearby mountains submerged by sea water in a valley. &lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="1149" LastEditDate="2015-03-17T18:23:38.360" LastActivityDate="2015-03-17T18:23:38.360" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4477" PostTypeId="1" AcceptedAnswerId="4481" CreationDate="2015-03-03T19:33:26.283" Score="12" ViewCount="1234" Body="&lt;p&gt;Is there a significant difference in the mass of the Earth between now and the time of the dinosaurs (250 - 75 million years ago)? I was just wondering if the force of gravity on dinosaurs would have been significantly less when they were around.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I gather, but may be wrong, that the mass of earth at present increases by around 10&lt;sup&gt;8&lt;/sup&gt;kg/day. All else being equal, one would expect the earth to have gained a mass, since 75 million years ago, of:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ 75^6 \times 365 \times 10^8 kg = 6.496 \times 10^{21} kg $$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The current mass of Earth according to Wikipedia is 5.972&lt;sup&gt;24&lt;/sup&gt;kg, so if my math is correct, the change since the time the dinosaurs went extinct would be less than 0.1%.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is my math correct here? If it is, would the change in the mass of the Earth over this period of time have had any noticeable effect on weight from its gravity?&lt;/p&gt;&#xA;" OwnerUserId="2630" LastEditorUserId="595" LastEditDate="2016-02-09T13:01:18.017" LastActivityDate="2022-08-24T16:22:01.723" Title="Change in earth mass since the time of the dinosaurs" Tags="|geophysics|earth-history|gravity|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="4478" PostTypeId="2" ParentId="4474" CreationDate="2015-03-03T19:37:39.147" Score="8" Body="&lt;p&gt;&lt;strong&gt;In theory&lt;/strong&gt;, if the Earth was a solid object, the Chandler wobble would be easy to understand. It's simply a result of the polhode rolling without slipping on the herpolhode lying in the invariable plane. In other words, $\mathrm I \dot \omega + \omega \times (\mathrm I \omega) = 0$, where $\mathrm I$ is the Earth's inertia tensor and $\omega$ is the Earth's angular velocity. The Chandler wobble is simply the consequence of the Earth not having a spherical mass distribution and the Earth not having it's angular momentum and angular velocity coaligned. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;In practice&lt;/strong&gt;, the Earth is not a solid object. The theory behind the Earth's orientation is rather (putting it mildly) complex. The best model involves over a thousand parameters. Unfortunately, this best model of the Earth's precession, nutation, and rotation does not explain the Earth's orientation. The Chandler wobble, along with a number of lesser phenomena, is an after-the-fact discrepancy between the very best analytic model and the very best observational results.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Knowing the Earth's orientation is extremely important to some sciences, high resolution astronomy in particular. The US Naval Observatory (USNO) publishes its estimates of the deviation of the Earth's true orientation versus that of the best analytic models on a daily basis. The USNO is a key member of the International Earth Rotation and Reference Systems (IERS, for short, and yes, the acronym doesn't work. It used to work.)&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-03-03T19:37:39.147" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4479" PostTypeId="2" ParentId="4477" CreationDate="2015-03-03T23:02:32.080" Score="6" Body="&lt;p&gt;Earth loses more mass as gases (especially Hydrogen and Helium) escape the atmosphere. Also, the numbers you mention as well as the mass of the air that is lost likely has large error bars associated with them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: For example see &lt;a href=&quot;http://www.bbc.co.uk/news/magazine-16787636&quot;&gt;here&lt;/a&gt; or &lt;a href=&quot;http://gizmodo.com/5882517/did-you-know-that-earth-is-getting-lighter-every-day&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2015-03-04T02:14:03.453" LastActivityDate="2015-03-04T02:14:03.453" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4480" PostTypeId="1" CreationDate="2015-03-04T13:52:22.347" Score="9" ViewCount="518" Body="&lt;p&gt;I'm interested in predicting when the local schools will be closed due to snow and other winter weather. I have a list of school closure dates and a rough sense of the criteria used to determine the closing of schools including, temperature, wind, precipitation, and their interactions.  Using a statistical technique (classical, Bayesian, or machine learning), I'd like to use both the actual weather the day before (t-1) and the predicted weather for the the day (t) to predict the county's decision. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to use the predicted weather at t and not the actual because that's the information known to the deciders when they have to make their decisions. For the actual, realized weather for t-1, I was planning on using the &lt;a href=&quot;http://www.ncdc.noaa.gov/cdo-web/webservices/v2#gettingStarted&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA API&lt;/a&gt;. But I'm at a loss on where to find weather prediction data. While I could do what @MarkRovetta suggests in the question on &lt;a href=&quot;https://earthscience.stackexchange.com/questions/3160/statistical-weather-prediction&quot;&gt;Statistical weather prediction&lt;/a&gt; and roll my own prediction model, that is harder than using a database and my lousy prediction model won't compare with the National Weather Service predictions available to the country officials. At best that will act like noise that will reduce the quality of my predictions. My primary question is therefore what sources are available for local weather predictions at various lags to the realized weather? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, are there tables of the predictive quality of forecasts at various time horizons? If, for example, the daily weather was predicted with 99% accuracy by 4 am that day, maybe there isn't an important difference between the predictions and the realized values. &lt;/p&gt;&#xA;" OwnerUserId="2631" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-03-06T23:23:01.483" Title="Predicting school closures with historical weather prediction data?" Tags="|meteorology|precipitation|weather-forecasting|open-data|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4481" PostTypeId="2" ParentId="4477" CreationDate="2015-03-04T14:34:06.580" Score="18" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;I gather, but may be wrong, that the mass of earth at present increases by around 10&lt;sup&gt;8&lt;/sup&gt;kg/day. All else being equal, one would expect the earth to have gained a mass, since 75 million years ago, of:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ 75^6 \times 365 \times 10^8 kg = 6.496 \times 10^{21} kg $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;First off, that should be &lt;span class=&quot;math-container&quot;&gt;$75\times10^6$&lt;/span&gt;, not &lt;span class=&quot;math-container&quot;&gt;$75^6$&lt;/span&gt;. That alone makes your estimate high by a factor of 2373. Correcting this error, the mass gain is only &lt;span class=&quot;math-container&quot;&gt;$2.7\times10^{18}$&lt;/span&gt; kg, rather than &lt;span class=&quot;math-container&quot;&gt;$6.5\times10^{21}$&lt;/span&gt; kg.&lt;/p&gt;&#xA;&lt;p&gt;Secondly, I've never seen anywhere close to that magnitude of mass gain. The article you cited in a comment gives a range of 5 to 300 metric tons per day. Your value of &lt;span class=&quot;math-container&quot;&gt;$10^8$&lt;/span&gt; kilograms per day is 100000 metric tons per day, which is high by at least a factor of 333 (and up to 20000). With this, the mass gain is between &lt;span class=&quot;math-container&quot;&gt;$1.5\times10^{14}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$8.2\times10^{15}$&lt;/span&gt; kg. This seems big, but it's tiny compared to the mass of the Earth.&lt;/p&gt;&#xA;&lt;p&gt;Thirdly, you are ignoring atmospheric losses. Almost all of the atmospheric losses are in the form of hydrogen and helium. Most of the lost hydrogen results from water vapor that makes its way from the surface of the Earth into the stratosphere and is dissociated. Most of the lost helium results from radioactive decay in the Earth. Both forms of atmospheric loss represent a decrease in the mass of the Earth. Estimates on this mass loss also vary widely, from 100 to 300 metric tons per day.&lt;/p&gt;&#xA;&lt;p&gt;Putting these widely varying estimates together means the mass of the Earth is increasing by as much as 200 metric tons per day (+300 mass gain, -100 mass loss), or decreasing by as much as 300 metric tons per day (+5 mass gain, -300 mass loss, and since the numbers vary so widely, that's just -300). Either way, it's small potatoes, even over the course of 75 million years. This means &lt;em&gt;g&lt;/em&gt; was between &lt;span class=&quot;math-container&quot;&gt;$13\times10^{-9}\,\text{m/s}^2$&lt;/span&gt; smaller than it is now and &lt;span class=&quot;math-container&quot;&gt;$9\times10^{-9}\,\text{m/s}^2$&lt;/span&gt; larger than it is now. Both of those numbers are very small.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-03-04T14:34:06.580" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4482" PostTypeId="2" ParentId="4480" CreationDate="2015-03-04T19:34:39.177" Score="6" Body="&lt;p&gt;I'm not aware of any datasets that are quite what you want (archived point forecasts for the next day).  There is less digestible data out there though.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://hurricane.ncdc.noaa.gov/pls/plhas/HAS.FileAppSelect?datasetname=9957ANX&quot; rel=&quot;noreferrer&quot;&gt;NOAA NCDC archived messages&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This website has archives of all messages that NOAA transmits.  The vast majority are unrelated to your needs, but if you look through the message types you might find something worthwile.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://nomads.ncdc.noaa.gov/dods/NCEP_GFS/&quot; rel=&quot;noreferrer&quot;&gt;NCDC NOMADS&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This site has archived GFS model grids.  This model is run 4 times per day and each run will have an analysis grid (current weather) and forecasts every 6 hours through the first few days of forecast time.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Most other archived data I could find are either observations or model reanalysis datasets, which won't work for your needs (except to better define the initial day t).  With the above datasets you could potentially put together the current weather at a specific place at 4 different times on day (t) and from each time have forecasts data for the next day, e.g.:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Observations / model analysis 12Z day t: 24 hour forecast for 12Z day t+1&lt;/li&gt;&#xA;&lt;li&gt;Observations / model analysis 18Z day t: 18 hour forecast for 12Z, 24 hour forecast for 18Z day t+1&lt;/li&gt;&#xA;&lt;li&gt;Observations / model analysis 00Z day t: 12 hour forecast for 12Z, 18 hour for 18Z and 24 hour for 00Z day t+1&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;From these you could then do your statistical analysis overall and explore how it may change as the day progresses and the model forecasts are shorter term.&lt;/p&gt;&#xA;&lt;p&gt;If wading through this data is not something you want to deal with, an alternative is to start archiving forecast data yourself going forward and building up a database over time.&lt;/p&gt;&#xA;&lt;h3&gt;Some caveats...&lt;/h3&gt;&#xA;&lt;p&gt;The NOMADS GFS data is pure model data, no forecaster input.  This is not what decision makers will be using directly.  This data will be made more consumable and be tweaked by forecasters before dissemination to the public.  If the NOAA message archive contains suitable forecasts data, that data will have likely been filtered through a forecaster and close to what would be displayed on the NWS website as a forecast.&lt;/p&gt;&#xA;&lt;p&gt;School closings are chaotic.  The same weather will not yeild the same closures.  Sometimes schools will stay open when faced with a worse forecast than a time they recently closed.  The criteria for closing may be a moving target as usable &amp;quot;snow days&amp;quot; are used up.  School closing thresholds will vary regionally (Florida schools would be closed Dec - March if subjected to a Michigan winter).  You may come up with a good forecast for when a school &lt;em&gt;should&lt;/em&gt; close, but don't be surprised if it doesn't correlate well with actual closings.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-03-04T19:34:39.177" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4484" PostTypeId="2" ParentId="3167" CreationDate="2015-03-06T03:02:05.307" Score="27" Body="&lt;p&gt;I'm a volcanologist and I have worked on erupting volcanoes. First of all, volcanologists almost never actually wear those suits. Heat is almost never the hazard that matters in the situations in which we work. The hazards are usually the chance of being hit by ballistics, or getting gassed. The reason you see those suits so often is that they look really cool on TV.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do know that Katia and Maurice Krafft wore them commonly, but their goal was to get as close to explosive eruptions as possible, as frequently as possible, for as long as possible. This strategy leads to death. It was a tragedy when the Kraffts (and 41 others) were killed at Unzen, but not entirely a surprising one, in retrospect. Modern volcanologists tend to be far more cautious and you might say that the heroic age of volcanology is over.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you're working on an erupting volcano, some major things you can do to reduce risk are:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Wear a helmet. This would have saved lives at Galeras.&lt;/li&gt;&#xA;&lt;li&gt;Reduce the amount of time you spend in the hazard zone. This means you need to work quickly, which often means carry less and don't wear silly protective gear like heat suits.&lt;/li&gt;&#xA;&lt;li&gt;Wear a gas mask, usually with SO&lt;sub&gt;2&lt;/sub&gt; scrubber cartridge. Ever try to jog up a hill in one of these? It becomes hard to breathe, and the mask quickly fills up with condensation from your breath. Communication through a radio or otherwise is hindered. Everything takes longer, so sometimes the masks are left off in the interest of #2.&lt;/li&gt;&#xA;&lt;li&gt;Increase your situational awareness. Maintain communications with someone who is watching data from instruments such as seismometers and tiltmeters. Also, make sure you have unobstructed vision so that you can potentially step out of the way of lava bombs which are falling towards you. Again, PPE such as a heat suit or even a gas mask can work against this.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;As for the idea of &quot;picking up&quot; lava with your hands, remember that lava is extremely viscous, so it takes quite a lot of force to pull a sample out of a flow. The colder lavas to which you refer are even more viscous than hotter lavas. Anyway, I doubt there are any gloves that can deal with prolonged contact with a 650C fluid. (Remember that fluids and solids are far more conductive than a gas and will transfer far more heat.) I think trying to sample lava with hands would be far more &quot;awkward&quot; than using a pole, which is really quite a simple, easy way to do it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: I just thought of another reason volcanologists can't dress like firefighters. Expense. Volcanologists have an extremely hard time getting sufficient funding. I actually asked for an SCBA for my work in the fumarolic ice caves of Mt Erebus, where CO&lt;sub&gt;2&lt;/sub&gt; is high. We couldn't afford it on our grant. Instead, I just carefully monitor gas levels and there are caves which I cannot enter because we read dangerous levels of gas at the entrances.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: I highly recommend that anyone interested in this subject read No Apparent Danger and Volcano Cowboys.&lt;/p&gt;&#xA;" OwnerUserId="63" LastEditorUserId="18081" LastEditorDisplayName="user889" LastEditDate="2020-01-29T14:24:55.823" LastActivityDate="2020-01-29T14:24:55.823" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="4485" PostTypeId="1" CreationDate="2015-03-06T03:32:11.463" Score="5" ViewCount="73" Body="&lt;p&gt;Why is seawater saline and not fresh? Could it be saturated with anything else, like, say, dissolved metal?&lt;/p&gt;&#xA;" OwnerUserId="2637" LastEditorDisplayName="user889" LastEditDate="2015-03-06T11:41:06.397" LastActivityDate="2015-03-06T11:41:06.397" Title="Why is seawater saline?" Tags="|ocean|geochemistry|water|" AnswerCount="0" CommentCount="1" ClosedDate="2015-03-06T13:53:52.927" ContentLicense="CC BY-SA 3.0" />
  <row Id="4486" PostTypeId="2" ParentId="4470" CreationDate="2015-03-06T10:35:42.187" Score="3" Body="&lt;p&gt;Lovett (2010) describe that as the soils in the Amazon Basin are actually nutrient poor, due to nutrients such as the phosphorous and iron supplied by the Saharan dust, being leached out via the higher rainfall.  The Saharan sediment is rich in nutrients as, according to Lovett (2010), it is essentially dried up lake bed sediments, mostly (56%, according to Fisher, 2007) coming from the Bodélé depression in Chad, Africa, which is composed of diatom shells which have significant (but not excessive) amounts of phosphorous and iron - this is a finite source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mahowald et al. (2014) explain that phosphorus availability constrains both carbon uptake and loss, hence, the amount of phosphorus in a forest is a limiting factor for rainforests (and other environments).  Atmospheric phosphorus, such as that from the Sahara is linked with the long term productivity of the Amazon.  Mahowald et al. also state that biomass burning is also a source of aerosol phosphorus.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of variability, Lovett also explains that these plumes are seasonal - during summer, they go across the Caribbean and winter, traversing south to the Amazon.  It is believed that at &lt;em&gt;current&lt;/em&gt; rates of dust dispersal, this nutrient input could last for another millennia - however, there is considerable uncertainty due to uncertainty in the climate models about the Sahara becoming wetter or drier in future.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If drier, Lovett asserts that there would be more dust, allowing the continued input to the Amazon, whereas increased precipitation, i.e. a wetter Sahara would result in less dust, hence less nutrient input to the Amazon.  Miller et al. (2014) explain that many climate models predict that enhanced dust aerosol loading would reduce precipitation due to the dimming effect reducing evaporation, hence making the environment drier.  However, aerosols, including dust, are a major source of uncertainty in climate modelling.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anthropogenic activity is also a significant source of uncertainty in long term climate modelling, it is suggested by Mahowald et al. that current land use changes in the Amazon itself is having a significant effect on the phosphorus input in the Amazon and surrounding forests.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A generalised view of the phosphorus cycle is provided below (from &lt;a href=&quot;http://en.wikipedia.org/wiki/Phosphorus_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/NdiM6.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the Amazon, the important differences are that atmospheric deposition is a vital input, and that leaching and runoff are more important loss mechanisms. (Crop harvest is also relevant due to human activity in the basin).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;References&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fisher, 2007, &lt;a href=&quot;http://www.newscientist.com/article/dn10880-amazon-forest-relies-on-dust-from-one-saharan-valley.html#.VPltx_mUcVY&quot; rel=&quot;nofollow noreferrer&quot;&gt;Amazon forest relies on dust from one Saharan valley&lt;/a&gt;, &lt;em&gt;New Scientist&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lovett, 2010, &lt;a href=&quot;http://www.nature.com/news/2010/100809/full/news.2010.396.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;African dust keeps Amazon blooming&lt;/a&gt;, &lt;em&gt;Nature News&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mahowald et al. 2014, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2005GB002541/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;Impacts of biomass burning emissions and land use change on Amazonian atmospheric phosphorus cycling and deposition&lt;/a&gt;, &lt;em&gt;Global Geochemical Cycles&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Miller et al. 2014, &lt;a href=&quot;http://link.springer.com/chapter/10.1007/978-94-017-8978-3_13&quot; rel=&quot;nofollow noreferrer&quot;&gt;Impact of Dust Radiative Forcing upon Climate&lt;/a&gt;, &lt;em&gt;Mineral Dust&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-03-06T11:08:46.383" LastActivityDate="2015-03-06T11:08:46.383" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4487" PostTypeId="2" ParentId="4480" CreationDate="2015-03-06T14:49:30.790" Score="4" Body="&lt;p&gt;&lt;a href=&quot;https://weatherspark.com/&quot; rel=&quot;nofollow&quot;&gt;Weatherspark.com&lt;/a&gt;, my favorite weather site of late, allows the user to pull forcasts from three sources: NOAA, met.no, and worldweatheronline.  Both of the second options provide forecasts for the entire world, and have an API.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can find information on the met.no API &lt;a href=&quot;http://api.met.no/weatherapi/documentation&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt; and information on the WWO API &lt;a href=&quot;http://www.worldweatheronline.com/api/&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;.  In particular, the WWO API page says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Our local weather API provides current weather conditions and hourly weather forecast for up to 15 days across worldwide locations. Local weather API also provides access to monthly climate average data to deliver aggregate weather across the world.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I have never tried using either service, so I can't promise that they will have exactly what you need, but hopefully this helps.&lt;/p&gt;&#xA;" OwnerUserId="53" LastActivityDate="2015-03-06T14:49:30.790" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4488" PostTypeId="2" ParentId="4466" CreationDate="2015-03-06T23:17:35.497" Score="10" Body="&lt;p&gt;Many studies, observations and measurements indicate that a great deal of the water recharges from the eastern highlands (Great Dividing Range).  This answer focuses on Governmental reports (including the &lt;a href=&quot;http://www.csiro.au/&quot; rel=&quot;noreferrer&quot;&gt;CSIRO&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the CSIRO report &lt;a href=&quot;https://publications.csiro.au/rpr/download?pid=csiro:EP132693&amp;amp;dsid=DS5&quot; rel=&quot;noreferrer&quot;&gt;Hydrostratigraphy, hydrogeology&#xA;and system conceptualisation of the Great Artesian Basin&lt;/a&gt; (2012), the Great Artsian Basin consists of complex geological and hydrogeological features.  This extensive study of the basin indicated no recharge from Papua New Guinea, stating that the recharge areas as being from folded Mesozoic rocks surrounding the basin in the central and southern parts, and Cenozoic aged recharge areas around the Gulf of Carpentaria in the north. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The recharge areas of the Great Artesian Basin are, according to the &lt;a href=&quot;http://www.environment.gov.au/node/22567&quot; rel=&quot;noreferrer&quot;&gt;Australian Government Department of the Environment&lt;/a&gt; is mainly from rainfall on the highlands (near to the western margin of the Great Dividing Range) to the east of the Basin (with some from the western margin), as shown in the image below (from the Dept webpage):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/bnSot.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Source:after Habermehl and Lau (1997). The shaded patterns broadly represent the&#xA;recharge area; arrows represent modelled flow lines after Welsh (2000). Dashed&#xA;lines represent spring clusters updated from Habermehl.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One major observation is that the top of Cape York is indicated as a recharge area, however, the CSIRO report details that this is recharge area is the Coen Inlier, just to the south of the shaded are.  Also noted is that there is discharge into the Gulf of Carpentaria in the north - according to the CSIRO, the basin extends into the Gulf of Carpentaria.  Although in all 3 reports there is no mention of recharge through the Torres Strait, the most any such discharge could influence, is the part of the basin in the Cape York/Carpentaria area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A cross-section of a section of the basin is show in the image below (from the &lt;a href=&quot;http://wetlandinfo.ehp.qld.gov.au/wetlands/ecology/aquatic-ecosystems-natural/groundwater-dependent/unweathered-sandstone/&quot; rel=&quot;noreferrer&quot;&gt;Queensland Government WetlandInfo webpage&lt;/a&gt;, clearly modelling the recharge areas (for the most part) being from the highlands on the eastern margin of the basin:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/crcXu.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Additional References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Habermehl MA and Lau JE 1997, Hydrogeology of the Great Artesian Basin (Map at scale&#xA;1:2500000), Australian Geological Survey Organisation, Canberra&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Welsh WD 2000, GABFLOW: A steady state groundwater flow model of the Great Artesian&#xA;Basin, Bureau of Rural Sciences, Canberra. &lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-03-07T09:28:24.023" LastActivityDate="2015-03-07T09:28:24.023" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4489" PostTypeId="2" ParentId="4480" CreationDate="2015-03-06T23:23:01.483" Score="6" Body="&lt;p&gt;The National Digital Forecast Database (NDFD) is archived by NCDC here: &lt;a href=&quot;http://nomads.ncdc.noaa.gov/data/ndfd/&quot; rel=&quot;noreferrer&quot;&gt;http://nomads.ncdc.noaa.gov/data/ndfd/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The NDFD contains gridded forecasts across the U.S. produced by NWS forecasters. You can also get NDFD output in realtime from a variety of sources, including the NWS itself: &lt;a href=&quot;http://www.nws.noaa.gov/ndfd/technical.htm&quot; rel=&quot;noreferrer&quot;&gt;http://www.nws.noaa.gov/ndfd/technical.htm&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1245" LastActivityDate="2015-03-06T23:23:01.483" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4490" PostTypeId="1" AcceptedAnswerId="4497" CreationDate="2015-03-07T09:21:30.547" Score="8" ViewCount="7456" Body="&lt;p&gt;Looking at the ashfall distribution map from the 1980 eruption of Mt. St. Helens (below), there is a measured 'patch' of ash depth significant enough to be measured occurring in Oklahoma.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/j4t6e.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What caused a measurable patch of Mt. St. Helens' ash to be deposited across Oklahoma?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2021-09-30T05:15:49.187" Title="What caused a measurable patch of Mt. St. Helens' ash to be deposited across Oklahoma?" Tags="|volcanology|volcanic-hazard|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4491" PostTypeId="1" AcceptedAnswerId="4495" CreationDate="2015-03-07T17:05:43.910" Score="15" ViewCount="16996" Body="&lt;p&gt;It seems to be given that around my country everybody believes in water veins (that's the best that &lt;a href=&quot;http://en.wikipedia.org/wiki/Google_Translate&quot; rel=&quot;noreferrer&quot;&gt;Google Translate&lt;/a&gt; could come up with. Basically underground water currents) that somehow affect humans. For example, one of the beliefs is that if you put your bed over one of these water veins and sleep on it, you'll start getting heart problems within in a couple of years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since I'm slightly more skeptic, I tried googling around, but all I found was some weird new age websites. So I'm asking the specialists. Is this underground water veins health effect thing real?&lt;/p&gt;&#xA;" OwnerUserId="2641" LastEditorUserId="502" LastEditDate="2015-03-08T10:18:38.400" LastActivityDate="2021-04-21T09:00:28.793" Title="Water veins underground causing health problems" Tags="|groundwater|water|" AnswerCount="2" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="4493" PostTypeId="5" CreationDate="2015-03-07T19:17:33.593" Score="0" Body="&lt;p&gt;Questions related to permafrost, either to a process implying the frozen ground, the permafrost dynamics or when localized in a permafrost zone/region (as in periglacial). &lt;a href=&quot;/questions/tagged/permafrost&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged &amp;#39;permafrost&amp;#39;&quot; rel=&quot;tag&quot;&gt;permafrost&lt;/a&gt; is a subset of &lt;a href=&quot;/questions/tagged/glaciology&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged &amp;#39;glaciology&amp;#39;&quot; rel=&quot;tag&quot;&gt;glaciology&lt;/a&gt; and often complements it, when the focus is on the frozen ground instead of glacier ice, ice-caps or sea-ice.&lt;/p&gt;&#xA;" OwnerUserId="2958" LastEditorUserId="2958" LastEditDate="2019-12-31T19:42:08.473" LastActivityDate="2019-12-31T19:42:08.473" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="4494" PostTypeId="4" CreationDate="2015-03-07T19:17:33.593" Score="0" Body="Questions related to permafrost, either to a process implying the frozen ground, the permafrost dynamics or when localized in a permafrost zone/region (as in periglacial). It is a subset of the [glaciology] tag and often complements it, when the focus is on the frozen ground instead of glacier ice, ice-caps or sea-ice." OwnerUserId="1411" LastEditorUserId="2470" LastEditDate="2019-12-31T05:26:31.520" LastActivityDate="2019-12-31T05:26:31.520" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="4495" PostTypeId="2" ParentId="4491" CreationDate="2015-03-07T20:12:41.517" Score="14" Body="&lt;p&gt;In my opinion, there is no such thing as water veins as described &lt;a href=&quot;http://swissharmony.com/en/water-veins-neutralised&quot; rel=&quot;noreferrer&quot;&gt;in this article&lt;/a&gt;, but, it is a fact that there is water circulation underground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the natural environment, water can either circulate in porous mediums (like within the small spaces between sand grains in sandy soils) or as underground streams. There is also the concept of the water table and aquifer recharge and depletion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This schematic provides a broad picture on the importance of groundwater&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/gqAaN.jpg&quot; alt=&quot;USGS groundwater&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More info &lt;a href=&quot;http://wi.water.usgs.gov/glpf/cn_nt_sys.html&quot; rel=&quot;noreferrer&quot;&gt;here as well&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some regions composed of rocks, especially carbonates (karst) can have more often channelized underground streams, as the ground is not necessarily porous so water is kind of forced to flow where there is an opening (see following figure). (More info on karstic landscape &lt;a href=&quot;http://www.esi.utexas.edu/outreach/caves/karst.php&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/uN7S1.jpg&quot; alt=&quot;karst&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So that was a small overview on how water can circulate underground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then people getting sick from water circulating underground is not because of the veins &lt;em&gt;per se&lt;/em&gt;, it could be because of moisture (or many other factors). But then living near a lake or any streams, any wet areas or in a badly insulated house could make people sick as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is 'old wives' tale' (no offense - English is not my primary language I am not sure how to say) and is not really a thing as presented in the &lt;a href=&quot;http://swissharmony.com/en/water-veins-neutralized&quot; rel=&quot;noreferrer&quot;&gt;http://swissharmony.com/en/water-veins-neutralized&lt;/a&gt; site. There has been no new research in a medical paper about geopathy since 1940 (wonder why?). You are doing well in being skeptical! To conclude I am sure many people living in drylands would be more than happy to be  'sick' over a vein.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastEditorDisplayName="user889" LastEditDate="2015-03-09T20:30:58.420" LastActivityDate="2015-03-09T20:30:58.420" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4496" PostTypeId="2" ParentId="4491" CreationDate="2015-03-07T22:55:45.837" Score="6" Body="&lt;p&gt;The other thing to be mindful about is &lt;strong&gt;near surface&lt;/strong&gt; water or moisture in soil resulting from a high water table, poor soil drainage or a leaking water pipe. Such moisture can lead to rising damp in buildings. This can bring with it salts from the ground that get left stone, bricks and mortar which can lead to deterioration of the structure of the building.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other thing that I have seen in houses which have an air space between the ground and the internal floor boards is that such moisture and dampness can create conditions favourable for mould. Depending on circumstances, above the floor boards in the house everything can appear as if there are no problems but beneath the floor boards mould can be rampant. If this occurs under a bedroom, over time, in susceptible people the mould can cause breathing problems and other health issues.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-03-07T22:55:45.837" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4497" PostTypeId="2" ParentId="4490" CreationDate="2015-03-08T04:15:43.813" Score="9" Body="&lt;p&gt;I will propose an explanation. From experience I would say it have something to do with the US meteorological systems (systems as in masses of air) active the 18th of May 1980 and the week(s) after.&lt;/p&gt;&#xA;&lt;p&gt;A bit of background : air masses can be high pressure (cool, and stable) or low pressure (warmer, more energy, more volatile, less stable). The next figure show in red a low unstable and warm system, and in blue a cool, stable system. (&lt;a href=&quot;http://www.metoffice.gov.uk/learning/learn-about-the-weather/how-weather-works/highs-and-lows/pressure&quot; rel=&quot;nofollow noreferrer&quot;&gt;full website here&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/FrlMU.jpg&quot; alt=&quot;air-systems&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;Further, let's take into account the meteorological nature of Oklahoma - as an area in a volatile sector, where warm wet air masses from the gulf collide with colder, dryer masses from the west and the north - area part of what is broadly know as &lt;a href=&quot;http://en.wikipedia.org/wiki/Tornado_Alley&quot; rel=&quot;nofollow noreferrer&quot;&gt;the tornado alley&lt;/a&gt;. On the wiki page for OK we see a typical system condition favorable for volatile weather. Green masses are warm, blue are cold and red is where the action is likely to occur.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/GJdy2.png&quot; alt=&quot;Tornado Alley&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;Tornado or other frequent wild weather events are the result of a clash between those widely different air masses, temperature, moisture and pressures often leading to storm cells or other unpleasant windy/stormy situations.&lt;/p&gt;&#xA;&lt;p&gt;Now let's get back to our volcano. I found those &lt;a href=&quot;https://library.noaa.gov/Collections/Digital-Collections/US-Daily-Weather-Maps&quot; rel=&quot;nofollow noreferrer&quot;&gt;daily meteorological maps&lt;/a&gt; from the NOAA. When entering the proper dates, let's say 18th of May 1980 and the week after, we see the various systems in action. To keep things simple, I picked the 18th of May, and  the 21st.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/SXp5W.jpg&quot; alt=&quot;18thofmay1980&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;The 18th of May there was a low pressure system about right over the volcano - which was ideal to transport and displace a lot of ashes very far. The 20th, at 7:00 am, there was a Low in formation over Oklahoma which would become full fledged the 21st (see figure) and there was bad weather that day over Oklahoma City because of clashing cell. Eventually causing precipitation (rain and ash?).&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/gccI8.jpg&quot; alt=&quot;21thofmay1980&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;I am not a climate-meteo-specialist, but I have good confidence that this scenario could explain a part of the reason why there is ash in Oklahoma.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastEditorUserId="6298" LastEditorDisplayName="user889" LastEditDate="2021-09-30T05:15:49.187" LastActivityDate="2021-09-30T05:15:49.187" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="4498" PostTypeId="1" AcceptedAnswerId="4501" CreationDate="2015-03-08T07:22:43.173" Score="9" ViewCount="23872" Body="&lt;ol&gt;&#xA;&lt;li&gt;The core of the sun has a temperature of 15,000,000 °C. &lt;/li&gt;&#xA;&lt;li&gt;The surface of the sun has temperature around 5,000 °C.&lt;/li&gt;&#xA;&lt;li&gt;The sun is around 93 million miles (150 million km) away from earth.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;My Question:&lt;/strong&gt; With a surface of 5,000 °C, how does the sun provide heat for earth 93 million miles (150 million km) away?&lt;/p&gt;&#xA;" OwnerUserId="2644" LastEditorUserId="725" LastEditorDisplayName="user889" LastEditDate="2017-05-06T04:33:13.890" LastActivityDate="2017-05-06T04:33:13.890" Title="How does the Sun heat the Earth?" Tags="|temperature|planetary-science|earth-system|atmospheric-radiation|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4500" PostTypeId="1" CreationDate="2015-03-08T20:55:09.993" Score="8" ViewCount="933" Body="&lt;p&gt;I have heard the term mentioned many times in seminars, and in papers on remote sensing. What does it mean? References would be helpful if available. &lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorDisplayName="user889" LastEditDate="2015-03-08T21:10:09.953" LastActivityDate="2015-03-16T17:54:02.413" Title="What is a Geophysical Model Function (GMF)?" Tags="|geophysics|models|remote-sensing|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4501" PostTypeId="2" ParentId="4498" CreationDate="2015-03-08T21:52:58.917" Score="18" Body="&lt;p&gt;It is a question of radiation emission - the temperature of the Sun's 'surface' is about 5500°C (according to &lt;a href=&quot;http://earthobservatory.nasa.gov/Features/EnergyBalance/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA Earth Observatory&lt;/a&gt;), at that temperature, it emits radiation in the UV, visible and near infra red region - due to the fact that the hotter an object is, the smaller the wavelength radiation is emitted, as can be seen in the generalised image below (from NASA):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/2P6Dl.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Note: the temperature of the Earth shown is an approximattion of its blackbody temperature, explained in the answer to the question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/825/what-would-be-the-temperature-of-earth-if-there-was-no-atmosphere&quot;&gt;What would be the temperature of earth if there was no atmosphere?&lt;/a&gt;&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Realistically, &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/U9azk.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Source: &lt;a href=&quot;http://en.wikipedia.org/wiki/Sunlight&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not all of this radiation reaches the top of Earth's atmosphere reaches the surface, a proportion is reflected off the atmosphere and some is absorbed by the atmosphere (as shown as the difference between the yellow and red in the diagram above) - but a good proportion reaches the Earth's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But that is not the entire picture, we receive this 'shortwave' radiation from the Sun:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/arKuW.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which is also balanced by an equal amount of energy radiating into space as 'longwave' thermal infrared radiation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/h3n9G.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(Both images from NASA Earth Observatory)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which leads to a major point - we have an atmosphere and a natural 'greenhouse effect' due to the water vapour and carbon dioxide (and other components) that are seen in the above solar radiation spectrum diagram. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some of the thermal infrared is absorbed by the atmosphere and re-radiated back to the surface. This radiation budget is shown below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/gJkDs.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Source: &lt;a href=&quot;http://ceres.larc.nasa.gov/ceres_brochure.php?page=2&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Something to consider, looking at the value the NASA has for the incoming radiation reaching the Earth's surface - 168 Wm&lt;sup&gt;-2&lt;/sup&gt; - imagine that being a 168 watt light globes for every square metre - that value increases markedly when the re-radiated thermal infrared is taken into account.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, please view the YouTube clip &lt;a href=&quot;https://www.youtube.com/watch?v=dg_DOM1OQoo&quot; rel=&quot;nofollow noreferrer&quot;&gt;How the Sun Heats the Earth&lt;/a&gt; which is a handy verbal and diagrammatic explanation of the content of this answer.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-03-08T22:15:53.553" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4502" PostTypeId="1" CreationDate="2015-03-09T15:21:54.083" Score="9" ViewCount="3193" Body="&lt;p&gt;Recently I have been selected for the National Camp of &lt;a href=&quot;http://en.wikipedia.org/wiki/International_Earth_Science_Olympiad&quot;&gt;INTERNATIONAL EARTH SCIENCE OLYMPIAD&lt;/a&gt; of my country. How do I prepare for it? Resources, books, etc. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know there are 4 parts- geology, hydrosphere, atmosphere and astronomy. Astronomy isn't much of a problem for me (I can manage it). I need the most help in geology. Please see that complex details are not asked in it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the syllabus, please see &lt;a href=&quot;https://www.sites.google.com/site/ineso555/syllabus---entrance-test&quot;&gt;https://www.sites.google.com/site/ineso555/syllabus---entrance-test&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2648" LastEditorUserId="111" LastEditDate="2015-03-13T19:23:37.053" LastActivityDate="2015-03-13T22:23:05.130" Title="How do I prepare for the International Earth Science Olympiad?" Tags="|atmosphere|geology|hydrology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4503" PostTypeId="1" AcceptedAnswerId="4510" CreationDate="2015-03-09T18:21:23.610" Score="19" ViewCount="8753" Body="&lt;p&gt;My daughter, age 8, wants to do her science fair project in paleontology. For the fair, we need to come up with a question that can lead to a hypothesis, then apply the scientific method to test this hypothesis. The wall we are hitting is that we don't know what kinds of tests paleontologists use in their work. Can anyone offer suggestions of where we can start to come up with our question, and what sort of tests would be useful in the process? I do not want the project spelled out for us, just a place to start so that we can learn along the way. Thanks. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I just wanted to address the comment about science fair participation. We are homeschoolers. When I refer to us as we concerning my daughter's project, it is not because I am going to be doing her work for her, but because I am a part of the process. Also, I find that in homeschooling, I learn a lot, too. The work and ideas will be hers. Thank you for your concern. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further information: She is interested in prehistoric sharks. We have joined the Dallas (TX) Paleontology Society and will be going out to hunt fossils with them soon (and will continue well after the science fair). We traveled to UTA to talk to a micropaleontologist and learn about his work, and get ideas. He offered use of a high powered microscope (with enough notice), so that is a resource available to us. We have met Roger Farrish, who wrote a book of prehistoric sharks and rays of Texas. He is a resource. Homeschooling is more adventure than not. I keep asking, everywhere I can, for input from others int he paleo- fields as my background is in cultural anthropology, and culinary. We do appreciate your help. &lt;/p&gt;&#xA;" OwnerUserId="2649" LastEditorUserId="111" LastEditDate="2016-04-21T02:55:39.523" LastActivityDate="2016-04-21T02:55:39.523" Title="Paleontology science fair ideas?" Tags="|paleontology|science-fair-project|" AnswerCount="6" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4504" PostTypeId="2" ParentId="4503" CreationDate="2015-03-09T20:44:34.287" Score="8" Body="&lt;p&gt;&lt;strong&gt;Palaeontologists use lots of methods to investigate past life.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Like most sciences these day, palaeontology is a growing field. More scientists are applying more methods in more sophisticated ways. The literature — what we 'know' — grows and grows. So palaeontologists use hundreds of different methods and tools today; indeed there's &lt;a href=&quot;http://www.jpaleontologicaltechniques.org/&quot; rel=&quot;nofollow&quot;&gt;a whole journal&lt;/a&gt; dedicated to the subject!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But like a lot of other geological disciplines, it's more or less impossible to test a hypothesis rigorously, because there are no actual dinosaurs, they died out ages ago, and so we cannot know everything about them. So we have to get creative.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, a palaeontologist interested in how dinosaurs or early insects walked might...&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Make detailed drawings of some fossils of the organism.&lt;/li&gt;&#xA;&lt;li&gt;Use X-ray tomography to see through a specimen and look at a fossil in 3D.&lt;/li&gt;&#xA;&lt;li&gt;Make a 3D computer model to look at how the animal might have walked.&lt;/li&gt;&#xA;&lt;li&gt;Examine museum collections to look for evidence of a hypothesized gait, eg in field photos or in casts from actual outcrops — perhaps there's a track out there somewhere!&lt;/li&gt;&#xA;&lt;li&gt;Look at the chromosomes of similar modern animals to determine lineages and 'shared DNA', and compare walking styles.&lt;/li&gt;&#xA;&lt;li&gt;Build or 3D-print an actual model and see if it actually does what the scientist thinks.&lt;/li&gt;&#xA;&lt;li&gt;Dress up like a dinosaur or dragonfly and walk around on a beach or mudflat to study the footprints. (I'm sort of but not really joking.) &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.ca/search?q=dinosaur%20locomotion&amp;amp;source=lnms&amp;amp;tbm=isch&quot; rel=&quot;nofollow&quot;&gt;(Google around dinosaur locomotion for more!)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I realize you can't do all of this sort of thing for a science fair, but hopefully it illustrates that, when it comes to hypothesizing about the past, we have to come at problems from a few different angles, using high and low technology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this helps a bit, good luck with the project!!&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2015-03-10T12:19:13.213" LastActivityDate="2015-03-10T12:19:13.213" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4505" PostTypeId="1" AcceptedAnswerId="4512" CreationDate="2015-03-10T01:47:45.407" Score="22" ViewCount="7416" Body="&lt;p&gt;Forgive my ignorance of the subject but I was always wondered about the exact reason of this phenomenon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Vernal equinox happens around March 20, whereas autumnal equinox happens around September 22, so wherever you are in Northern Hemisphere, the length of the day, and consequently the amount of solar energy that reaches the place should be almost the same. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However the average temperatures differ widely, for example Toronto has average temperatures of 2°C to 6°C on March 20th, and 14°C to 19°C on September 22nd. So around 12°C difference &lt;a href=&quot;https://weatherspark.com/averages/28179/3/20/Toronto-Ontario-Canada&quot;&gt;[link]&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So obviously there is some sort of temperature inertia, as temperatures seem to experience a delay in responding to changes in day length.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the main reason for it? Is it effect of sea ice or snow-covered land albedo? Energy stored in oceans? Energy absorbed by melting snow and ice?&lt;/p&gt;&#xA;" OwnerUserId="2650" LastEditorDisplayName="user889" LastEditDate="2015-03-10T18:42:14.527" LastActivityDate="2022-04-22T23:01:26.313" Title="Why is March colder than September in Northern Hemisphere?" Tags="|climate|solar-terrestrial-physics|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4506" PostTypeId="2" ParentId="4473" CreationDate="2015-03-10T02:03:33.823" Score="6" Body="&lt;p&gt;I must admit that I was not well informed on the matter of offshore aquifers before reading this thread. Usually when I think about the hydrologic models I think of the water as a dynamic component of a system (snow, streams, moisture, glaciers) and not necessarily old water pockets somewhat trapped deep (and at the moment with no know perceptible input/ouput in the system). In line with those &lt;a href=&quot;http://www.eoearth.org/view/article/153627/&quot;&gt;classical hydrologic cycle model&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I searched a bit and found this paper on &lt;a href=&quot;http://phys.org/news/2013-12-scientists-vast-undersea-freshwater-reserves.html&quot;&gt;physorg.org&lt;/a&gt; which led me to other reads on the matter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apparently there is substantial offshore freshwater aquifers, trapped undersea. Water from Pleistocene, which probably got trapped during the glaciations, while the mean sea level was much lower. When the ice sheet (ex: Laurentidian) receded, sea level rose and freshwater in charged aquifers would be somewhat trapped and sealed. Multiple glaciation during the Pleistocene would have enabled the process to cycle multiple time during the last 2.5 M year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And yes - &lt;a href=&quot;http://www.nature.com/nature/journal/v504/n7478/full/nature12858.html&quot;&gt;the related paper in Nature&lt;/a&gt; specify that some of those 30 inventoried undersea aquifers have an onshore connection (Perth among others is listed there).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is pretty interesting but in my opinion there is not a ton of paper on the question. Yet I will keep this part of this (paleo!) hydrologic cycle in mind when such questions and discussions arise in the future.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2015-03-10T02:03:33.823" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4507" PostTypeId="2" ParentId="4503" CreationDate="2015-03-10T02:13:14.927" Score="8" Body="&lt;p&gt;An important branch of experimental palaeontology is studying the effects of natural processes on plant and animal remains. With that in mind, I would suggest trying to replicate the results of the 2013 &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_Ig_Nobel_Prize_winners&quot; rel=&quot;noreferrer&quot;&gt;(ig) nobel prize winners&lt;/a&gt; in archeology. Not only will you be testing a scientific hypothesis, you will be testing whether or not your daughter has what it takes to be a REAL scientist.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;2013 ARCHAEOLOGY PRIZE: Brian Crandall [USA] and Peter Stahl [CANADA, USA], for parboiling a dead shrew, and then swallowing the shrew without chewing, and then carefully examining everything excreted during subsequent days — all so they could see which bones would dissolve inside the human digestive system, and which bones would not.&lt;/p&gt;&#xA;&lt;p&gt;REFERENCE: &amp;quot;Human Digestive Effects on a Micromammalian Skeleton,&amp;quot; Peter W. Stahl and Brian D. Crandall, Journal of Archaeological Science, vol. 22, November 1995, pp. 789–97.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2651" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-03-10T02:13:14.927" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4508" PostTypeId="2" ParentId="4503" CreationDate="2015-03-10T03:37:19.390" Score="5" Body="&lt;p&gt;Looking the &lt;strong&gt;cladogram&lt;/strong&gt; tree at &lt;a href=&quot;http://en.wikipedia.org/wiki/Paleontology&quot;&gt;WP - Paleontology&lt;/a&gt; : &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Make her validate/deny (True/False) the following statements:  &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Mammal&quot;&gt;Mammals&lt;/a&gt; and &lt;a href=&quot;http://en.wikipedia.org/wiki/Bird&quot;&gt;birds&lt;/a&gt; are the most recent &lt;em&gt;inventions&lt;/em&gt; of Life (introduce her to &lt;a href=&quot;http://en.wikipedia.org/wiki/Class_(biology)&quot;&gt;Classification&lt;/a&gt;)  &lt;/li&gt;&#xA;&lt;li&gt;Mammals and birds are the only to have a protective 'coat': &lt;a href=&quot;http://en.wikipedia.org/wiki/Mammal#Endothermy&quot;&gt;feathers and fur&lt;/a&gt;  &lt;/li&gt;&#xA;&lt;li&gt;Mammals and birds are the only hotblooded (my comfortable temp is 37 ºC) and use a lot of energy to keep warm   &lt;/li&gt;&#xA;&lt;li&gt;Life evolves in response to environmental changes   &lt;/li&gt;&#xA;&lt;li&gt;When the ambient get colder its is time to wear a coat &lt;/li&gt;&#xA;&lt;li&gt;The ambient temperature aprox. 225 million years ago (&lt;a href=&quot;http://en.wikipedia.org/wiki/Mammal#The_mammals_appear&quot;&gt;beginning of mammals&lt;/a&gt;) was hotter than now (&lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/gridded/data.noaa.oisst.v2.html&quot;&gt;equatorial present temp&lt;/a&gt;: 29ºC )    &lt;/li&gt;&#xA;&lt;li&gt;It is possible that the dinosaurs became extinct because they froze to death?&lt;br&gt;&#xA;(between &lt;a href=&quot;http://en.wikipedia.org/wiki/Triassic%E2%80%93Jurassic_extinction_event&quot;&gt;Triassic/Jurassic extinction&lt;/a&gt; and &lt;a href=&quot;http://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_extinction_event&quot;&gt;Cretaceous/Paleogene extinction&lt;/a&gt; ) &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Ask the opinion of your daughter about the points above. Paradoxically there is no consensus on the points 6 and 7. I wonder why.&lt;br&gt;&#xA;In my profile there is a link to my lengthy and formal argumentation. &lt;/p&gt;&#xA;" OwnerUserId="2613" LastEditorUserId="2613" LastEditDate="2015-03-10T03:45:29.350" LastActivityDate="2015-03-10T03:45:29.350" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4509" PostTypeId="2" ParentId="4503" CreationDate="2015-03-10T07:27:36.070" Score="3" Body="&lt;p&gt;A small preface, my day job is as a school science teacher - and I have to say, I am thrilled to read of you and your daughter's intention of pursuing palaeontology using the scientific method for the Science Fair. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are some great (non-Wikipedia) resources online, one in particular is &lt;a href=&quot;http://www.paleoportal.org/&quot; rel=&quot;nofollow&quot;&gt;The Palaeontology Portal&lt;/a&gt;, which has a K-12 link, as well as links to &lt;a href=&quot;http://www.paleoportal.org/index.php?globalnav=paleopeople&quot; rel=&quot;nofollow&quot;&gt;interviews with palaeontologists&lt;/a&gt; as well.  But, a gem in the website is the &lt;a href=&quot;http://www.paleoportal.org/index.php?globalnav=doing_paleo&amp;amp;sectionnav=resources&amp;amp;type_id=5&quot; rel=&quot;nofollow&quot;&gt;Resources page&lt;/a&gt;. On the &lt;a href=&quot;http://www.paleoportal.org/index.php?globalnav=paleopeople&quot; rel=&quot;nofollow&quot;&gt;'PalaeoPeople'&lt;/a&gt; page, they state:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Paleontology goes well beyond dinosaurs! It is a dynamic science that seeks to uncover the history of all life on Earth. Paleontologists examine multiple lines of evidence that provide clues to that history, including fossils and how they are formed and preserved, stratigraphy, biogeography, histology, and chemistry.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Reading the biographies of palaeontologists will give some insights as to how palaeontologists approach solving hypotheses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another website that uses art to conceptualise palaeontological concepts is found in the Palaeontology Online webpage &lt;a href=&quot;http://www.palaeontologyonline.com/articles/2014/patterns-palaeontology-palaeoart-fossil-fantasies-recreating-lost-reality/&quot; rel=&quot;nofollow&quot;&gt;Patterns in Palaeontology: Palaeoart – fossil fantasies or recreating lost reality?&lt;/a&gt; - where hypotheses could be testing by careful visual reconstruction of their form (e.g. dinosaurs to birds), in particular:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Palaeoart attempts to model the appearance and habits of extinct animals by blending artistry with contemporary palaeontological thinking. Wherever possible, palaeoart relies on scientific evidence rather than artistic preference. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and crucially, and could be of help to your and your daughter's project:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;When executed well, such restorations accurately reflect how much is&#xA;  known about the subject species. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A series of diagrams showing the evolution of a particular species could be an option.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edited to add: With regards to prehistoric sharks, some inspiration could be drawn from the Shark World &lt;a href=&quot;http://www.sharks-world.com/prehistoric_sharks/&quot; rel=&quot;nofollow&quot;&gt;Prehistoric Shark&lt;/a&gt; page.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-03-11T01:06:33.430" LastActivityDate="2015-03-11T01:06:33.430" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4510" PostTypeId="2" ParentId="4503" CreationDate="2015-03-10T08:24:31.320" Score="4" Body="&lt;p&gt;To give you a quick overlook of the range of hypotheses one can test in modern paleontology you can have a look at the public database of project financed by the DFG (german science foundation). &lt;a href=&quot;http://gepris.dfg.de/gepris/OCTOPUS?context=projekt&amp;amp;findButton=historyCall&amp;amp;index=10&amp;amp;keywords_criterion=paleontology&amp;amp;task=doSearchSimple&quot; rel=&quot;nofollow&quot;&gt;Here is a query on paleontology&lt;/a&gt;. Some of them are in german but some others are in english and are usually written in a way understandable by non-paleontologists (since grant reviewers are not necessarily paleontologists) and (normally) the hypotheses are spelled out in the abstract (having written such a grant proposal last month I can confirm it is even supposed to be mandatory). Of course, they might be a bit complex for 8 years old but it might give you ideas on the kind of questions paleontologists try to answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As @HelderVelez mentioned one of the big question in modern paleontology is to determine to which extent speciations and extinctions are caused by interactions with the environment, interactions with other living beings (the so-called Red Queen Hypothesis) or randomness. One aspect of modern paleontology which has not been mentioned so far in the other answers and that come handy to answer such questions is quantitative paleontology. Many subdisciplines of paleontology (invertebrate paleontology, micropaleontology, palynology) have a very rich fossil record allowing statistically meaningful quantification. The Paleobiology database (found &lt;a href=&quot;https://paleobiodb.org/#/&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt; or &lt;a href=&quot;http://fossilworks.org/&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;) is a great resource for quantitative data on vertebrate and invertebrate paleontology and can help testing hypotheses on fossil biogeography (&quot;Have the tropics always been a hotspot of diversity&quot;), on mass extinctions (&quot;Did the end-Permian events affected only marine-based organisms or land-based organisms as well&quot;), etc. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quantification can also come from measurements and the hypotheses tested have then to do with the organisms evolution (&quot;is organism X more closely related to organism Y or Z&quot;), ontogeny (one of the big challenge in vertebrate paleontology nowadays being to differentiate what part of the observed morphological variations is due to speciation or ontogeny, i.e. are two specimens from different species or from the same species but one is a juvenile and the other an adult) or ecology (&quot;was organism X herbivore or carnivore&quot;, &quot;how was organism X walking&quot; etc).&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Finally, identifying the environment at the time of deposition of the outcrop where the fossil was found have always been the most straight-forward test done using fossils. It is also probably the easiest and most obvious hypothesis to test for an 8 years-old: go to a local fossiliferous outcrop (a geological map of your area will be necessary for this), make her look for fossils and answer whether or not the studied area was underwater at the moment this outcrop was deposited, or how deep it was, etc., based on the fossils she found.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly fossils can be used to test hypotheses on the age of the outcrop but unless your local outcrop happen to contain trilobites, ammonites or mammals, it might be too technical for an 8 years-old.&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2015-03-10T09:01:18.177" LastActivityDate="2015-03-10T09:01:18.177" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4511" PostTypeId="1" CreationDate="2015-03-10T12:41:16.057" Score="16" ViewCount="4197" Body="&lt;p&gt;How should I interpret the hourly precipitation forecasts? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of the time, when there is rain in the forecast, the maximum Probability of Precipitation (PoP) in the hourly forecast is about the same as the daily PoP. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My problem is that the hourly PoP forecast usually has several hours at that maximum probability.  If I naively add the odds of getting wet for each hour, I always get a total probability that is much higher than the daily PoP value.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, take an hypothetical day where the daily forecast has a 50% PoP.  For the same day, the hourly forecast has 4 hours with a 50% PoP for each hour.  If I compute the chance that I get rain in at least one of the 4 hours, I get 93% PoP (15 out of 16).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can I reconcile the total daily PoP calculated from the hourly forecast with the actual daily PoP?&lt;/p&gt;&#xA;" OwnerUserId="2653" LastEditorUserId="543" LastEditDate="2021-07-20T04:49:17.277" LastActivityDate="2021-07-20T04:49:17.277" Title="How to reconcile hourly vs. daily probability of precipitation in the forecast?" Tags="|precipitation|weather-forecasting|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="4512" PostTypeId="2" ParentId="4505" CreationDate="2015-03-10T12:49:10.850" Score="29" Body="&lt;p&gt;&lt;strong&gt;The phenomenon is called &lt;a href=&quot;http://en.wikipedia.org/wiki/Seasonal_lag&quot; rel=&quot;noreferrer&quot;&gt;seasonal lag&lt;/a&gt;.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2490/equinoxes-and-solstices-start-of-the-season-or-mid-season/2603#2603&quot;&gt;a more extensive answer elsewhere on this site&lt;/a&gt; but the basic idea is that temperature lags behind insolation by several weeks, because it takes time to change the mean temperatures of the land, the atmospehere, and especially oceans change their mean temperature. This diagram tries to show the lag, along with various ways of reckoning the seasons:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/gWNb5.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-03-10T12:49:10.850" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4513" PostTypeId="1" AcceptedAnswerId="4515" CreationDate="2015-03-11T12:28:13.340" Score="13" ViewCount="4274" Body="&lt;p&gt;Is there a correlation between how many hot springs an area has, and how frequent or severe the area's earthquakes are?&lt;/p&gt;&#xA;" OwnerUserId="2658" LastEditorUserId="28050" LastEditDate="2015-03-12T17:47:59.963" LastActivityDate="2020-03-18T03:53:18.593" Title="Is there a correlation between hot springs and earthquakes?" Tags="|seismology|earthquakes|geothermal-heat|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4514" PostTypeId="1" AcceptedAnswerId="4524" CreationDate="2015-03-11T15:20:30.953" Score="11" ViewCount="2260" Body="&lt;p&gt;The &lt;a href=&quot;http://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami&quot;&gt;2011 Tōhoku earthquake and tsunami&lt;/a&gt; was one of the biggest in modern history; the earthquake even moved Earth's axis for a very small, but measurable bit. The four years since then is not enough for hard climate data, but enough to have some insight to how the weather was influenced. So did it influence weather in any way that could be seen as &quot;impact on climate&quot;? If yes, how?&lt;/p&gt;&#xA;" OwnerUserId="101" LastActivityDate="2022-12-02T04:34:03.323" Title="What impact on climate did 2011 earthquake and tsunami have?" Tags="|climate|earthquakes|tsunami|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4515" PostTypeId="2" ParentId="4513" CreationDate="2015-03-11T19:31:50.420" Score="8" Body="&lt;p&gt;Hot springs usually exist in volcanic regions or in areas where there are extensive (normal) faults. The water circulates through the fault zones (basically damaged zones with high permeability) bringing heat from great depths. However these faults don't have to be active. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore a correlation between location of hot springs and present day seismic activity is not necessary but the faults were indeed active at some point in history.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: @winwaed: I wanted to add that there indeed are faults associated with Hot Springs in AR. I am including a figure of the region borrowed from a NPS publication &lt;a href=&quot;http://www.nature.nps.gov/geology/inventory/publications/reports/hosp_gri_rpt_body_print.pdf&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;. Look carefully at the figure in the lower right where water is flowing upwards through a fault. A lot of people have the misconception that there are no faults in the interior of plates. That is not always true. In fact quite the opposite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/51LAo.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2015-03-12T13:59:49.137" LastActivityDate="2015-03-12T13:59:49.137" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4516" PostTypeId="2" ParentId="4513" CreationDate="2015-03-11T21:44:29.257" Score="3" Body="&lt;p&gt;As a counter to @stali's answer, it is possible to have hot springs without volcanism or normal faulting - although these two scenarios do cover the most well known examples.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hot Springs, Arkansas exists because of the local geological structures (folding rather than faulting) that bring ground water up to the surface from deep in the Earth relatively quickly. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also radiogenic rocks (eg. granites) can increase the thermal gradient, making this scenario more likely. Eg. the UK's &quot;hot springs&quot;. Okay they're not that hot, but shallow boreholes found 60C water at Buxton (and nicely radioactive); and hot water in a Lafarge mine/quarry in Weardale (?). The last I heard, there were plans to turn the latter into a spa...&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2015-03-11T21:44:29.257" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4518" PostTypeId="1" CreationDate="2015-03-12T06:49:40.407" Score="15" ViewCount="275" Body="&lt;p&gt;I have fitted an ETAS model (unmarked) with an independent exponential magnitude distribution to a set of earthquake data. However, I do not know how to calculate the probability of the earthquake occurrence (or the probability of no events) during a certain time interval. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is there an explicit formula to compute the probability, like the one in the Poisson model?&lt;/strong&gt; &lt;/p&gt;&#xA;" OwnerUserId="2660" LastEditorDisplayName="user889" LastEditDate="2015-03-12T07:20:01.457" LastActivityDate="2021-11-01T02:05:10.550" Title="How to compute the earthquake occurrence probability under ETAS model" Tags="|seismology|earthquakes|models|statistics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4519" PostTypeId="2" ParentId="4513" CreationDate="2015-03-12T16:21:17.537" Score="10" Body="&lt;p&gt;&lt;strong&gt;Yes, there is a correlation.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words: places with hot springs are more likely to experience earthquakes than places without hot springs. The relationship is scale-dependent in time and space (your house might not sit on a hot spring but still get earthquakes). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ideally I'd dig around and find actual data to quantify this spatial correlation (and I hope someone does!), but for now I will settle for qualitative evidence at the continental scale. I offer a visual correlation between the two datasets in question. First, geothermal springs:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/gJmoQ.png&quot; alt=&quot;Map of geothermal springs in the US&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now earthquakes:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/EsOH1.gif&quot; alt=&quot;Map of earthquake hazard in the US&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Like any correlation in geoscience, it's not perfect. But, broadly speaking, there is one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Footnote:&lt;/strong&gt; Actually, there are at least two correlations. As with fracking for shale gas, well stimulations and other industrial activity in geothermal fields &lt;a href=&quot;http://news.ucsc.edu/2013/07/geothermal-earthquakes.html&quot; rel=&quot;noreferrer&quot;&gt;has recently been blamed&lt;/a&gt; for induced seismicity in places like the Imperial Valley of southern California. Sometimes correlation &lt;em&gt;does&lt;/em&gt; imply causation!&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-03-12T16:21:17.537" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4520" PostTypeId="1" AcceptedAnswerId="4534" CreationDate="2015-03-13T07:40:18.137" Score="2" ViewCount="1161" Body="&lt;p&gt;In seismic analysis, why is a –90 degree phase rotation required on the amplitude spectrum to produce the colored inversion operator?&lt;/p&gt;&#xA;" OwnerUserId="2662" LastEditorUserId="28050" LastEditDate="2015-03-13T10:37:12.743" LastActivityDate="2016-09-21T04:48:32.587" Title="Why is phase rotation needed to produce the colored inversion operator?" Tags="|geophysics|inversion|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4521" PostTypeId="1" AcceptedAnswerId="4522" CreationDate="2015-03-13T14:52:27.950" Score="7" ViewCount="712" Body="&lt;p&gt;Is the 2-D elevation wave spectrum (as a function of wavenumber and direction, with units of $m^4$) always positive? If so, why would that be the case?&lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorUserId="192" LastEditDate="2015-03-13T16:46:51.133" LastActivityDate="2022-12-06T05:13:51.487" Title="Is wave spectrum always positive and why?" Tags="|waves|wave-modeling|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4522" PostTypeId="2" ParentId="4521" CreationDate="2015-03-13T16:45:56.507" Score="9" Body="&lt;p&gt;Yes, wave variance or energy spectrum, direcional or non-directional is positive-definite as @aretxabaleta said in the comment. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In linear water-wave theory, the surface elevation is described as a linear superposition of sinusoids:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\eta(t) = \sum_{i-1}^{N}a_i \sin(f_i t + \phi_i)&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $a_i$, $f_i$ and $\phi_i$ are the amplitude, frequency and phase, respectively, of each wave component $i$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most commonly used wave spectrum is the wave variance spectrum. Wave variance is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\langle\eta^2\rangle = \dfrac{1}{2N}\sum_{i=1}^{N}a_i^2 = \sigma^2&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and wave variance spectrum $F(f)$ is defined such that:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;F(f)\Delta{f}=\dfrac{a_i^2}{2} &#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the limit of $N \rightarrow \infty$ (continuous spectrum), the following holds:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\int_{0}^{\infty}F(f)df = \sigma^2&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Being quadratic, both wave variance (spectrum integral) and individual discrete spectrum components are positive-definite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that so far we implied non-directional frequency spectrum, i.e. spectrum defined in frequency space. It can be also defined in wavenumber $k$ space, and the following holds:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\int_{0}^{\infty}F(k)dk = \int_{0}^{\infty}F(f)df = \sigma^2&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;F(k)\Delta{k} = F(f)\Delta{f}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;F(k) = F(f)c_g&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $c_g$ is group velocity of an individual component.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The non-directional spectrum is simply an integral of directional spectrum over all directions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\int_{0}^{\infty}F(k)dk = \int_{0}^{2\pi}\int_{0}^{\infty}F(k,\theta)dkd\theta&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Be careful about units here. All spectrum integrals must come up at $m^2$. Thus, $F(k)$ has units of $m^3$ and $F(k,\theta)$ has units of $m^3$ $rad^{-1}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are considering polar (spectral bins scaling with $k\theta$ instead of $\theta$) directional wavenumber spectrum such that:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\int_{0}^{2\pi}\int_{0}^{\infty}F(k,\theta)k\ dk\ d\theta = \sigma^2&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;then $F(k,\theta)$ has units of $m^4$ $rad^{-1}$.&lt;/p&gt;&#xA;" OwnerUserId="192" LastActivityDate="2015-03-13T16:45:56.507" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4523" PostTypeId="1" CreationDate="2015-03-13T17:15:02.577" Score="8" ViewCount="143" Body="&lt;p&gt;I was recently speaking with a geology professor over lunch at a university who has a theory that I've never heard before.  His postulation was quite compelling and I was hoping to do a little digging to see if anyone else has heard of such a theory with any supporting evidence.  Apparently this fellow is onto quite a discovery, but is not yet ready to release his findings.  Quite a bit of the discussion was simply over my head since I have never really studied geology in depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;He sets forth that magma is not actually created from heat / pressure buildup, etc., but rather that it is generated from a catalytic reaction from massive interactions of water with large group 1 and group 2 metal pockets or clusters within the earth's crust.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;He further explained how the water enters into these pockets via various fissures both from our oceans and other bodies of water (noting some study from last year where researchers found incredible volumes of water 700 kilometers underground).  One side note was regarding the contents of magmatic rocks being surprisingly high in alkali metals, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I noted, it was quite compelling, but I was out of my depth and I was curious as to whether others have heard such theories or seen such data before as I would quite like to understand this topic a bit better.&lt;/p&gt;&#xA;" OwnerUserId="2575" LastActivityDate="2016-09-21T04:50:30.437" Title="Magma resultant from group 1 and group 2 elements?" Tags="|geophysics|geology|volcanology|geochemistry|mantle|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4524" PostTypeId="2" ParentId="4514" CreationDate="2015-03-13T21:49:33.183" Score="13" Body="&lt;p&gt;Local effects are definitely possible, mainly from the tsunami itself - turbulence in the air from the waves and increased evaporation from flooded areas after.  However, it appears that the earthquake and tsunami has had no significant effect on the world's weather, particularly in the long term.  According to the Lamont-Doherty Earth Observatory, Columbia University web-article, &lt;a href=&quot;http://www.ldeo.columbia.edu/news-events/can-big-earthquakes-disrupt-world-weather&quot; rel=&quot;noreferrer&quot;&gt;Can Big Earthquakes Disrupt World Weather?&lt;/a&gt;, a key point is that although the earthquake released a massive amount of energy, it is not enough to disrupt the energy balance of the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A particular point is that one of the significant effects - the axial shift from the earthquake, is, according to the article, minimal compared to natural cyclical axial fluctuations.  The article also mentions that other major earthquake and tsunami events have the same minimal effects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although, some studies such as what gansub mentioned in comments, &lt;a href=&quot;http://www.ejournalofscience.org/archive/vol2no2/vol2no2_14.pdf&quot; rel=&quot;noreferrer&quot;&gt;Impact of tsunami on Tamil Nadu Monsoon Rainfall&lt;/a&gt;, suggest that the tsunami itself can cause disruptions to local and regional climatic systems  -particularly with rainfall patterns.  This is an ongoing study by the University of Canterbury's &lt;a href=&quot;http://www.geog.canterbury.ac.nz/department/staff/imans.shtml&quot; rel=&quot;noreferrer&quot;&gt;Dr Iman Soltanzadeh&lt;/a&gt; research &quot;The Atmospheric Impacts of Volcano and Large Tsunamis&quot; where land use modifications due to a tsunami would affect local and regional climate and weather patterns.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the effects on the thinner upper atmosphere were a bit more pronounced according to NASA observations reported in the web-article &lt;a href=&quot;http://visibleearth.nasa.gov/view.php?id=77377&quot; rel=&quot;noreferrer&quot;&gt;Quake and Tsunami make waves in the Atmosphere&lt;/a&gt;, causing ripples in the ionosphere (~85km above the surface), as can be seen in the image below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/PnRrs.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The quake caused acoustic and Rayleigh waves that reached the ionosphere in about 10 minutes, and the rolling motion of the tsunami caused gravity waves to propogate to the ionosphere in about 30-40 minutes, continuing westward even after the tsunami was stopped by the east coast of Japan.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most significant aspect of NASA's findings can be interpreted that as the waves (all types) propogate through the atmosphere from the earthquake rupture and tsunami to the ionosphere, they appear to cause no significant climatic disruption to the lower near-surface and even the middle layers of the atmosphere, further emphasising the conclusions made by the Lamont-Doherty Earth Observatory that large earthquakes and associated tsunami do not cause any long term affects on weather patterns.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-03-14T08:03:53.627" LastActivityDate="2015-03-14T08:03:53.627" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4525" PostTypeId="2" ParentId="4502" CreationDate="2015-03-13T22:23:05.130" Score="11" Body="&lt;p&gt;Here are a few, completely random advices I wished someone would have given me before I started to study geology. I'm aware of that this is over simplified, but I believe that it's good to start easy, gain interest and later, with experience, understand that you have been wrong. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good book to start with: &#xA;Earth: Portrait of a Planet by Stephen Marshak. It is used in many universities for undergraduate students. It has a lot of good illustrations and goes breathy through most aspects of earth science. I'd check that and memorize the diagrams and pictures. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.usgs.gov/&quot;&gt;http://www.usgs.gov/&lt;/a&gt; also have plenty of easy accessible material. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Make sure that you understand the concept of tectonics well and use that as a starting point for almost any geological discussion. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Don't forget the most basic physical properties. What works in a laboratory also works in larger scale. (E.g. Density will make light material float and heavy material sink. That's why rivers erodes the paths to the oceans and volcanoes erupt volatile rich lava. Oceanic crust is heavy and continental crust is light.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take one hour of your life to learn the geological periods (everyone should!). Use the periods as imaginary folders for fossils, orogenies, mass extensions and whatever you later come across. (E.g. 'Permian' will be something distinctive, just like 'Elephant', 'Qawwali' or 'Andhra'. You'll recognize it when you see/hear/feel it, even if it's difficult to describe in words!). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you read articles, always start with the latest, and work your way back. In this way you'll start with the modern concept and not get biased by earlier models. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Keep an interest in the present. You should know some biology to understand paleontology, some oceanography to understand deposition and hydrology to understand erosion etc. When you add time, we call it geology. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;And, if you start to study and research in geology or anything else, learn LaTeX and learn some basic programming, before you need it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Good luck with the Olympiad!&lt;/p&gt;&#xA;" OwnerUserId="2536" LastActivityDate="2015-03-13T22:23:05.130" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4526" PostTypeId="2" ParentId="4523" CreationDate="2015-03-14T06:49:03.553" Score="7" Body="&lt;p&gt;So let's break it down part by part:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;He sets forth that magma is not actually created from heat / pressure buildup, etc.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There is not a single mechanism for magma formation in the Earth. Magma can form by heating, decompression, infiltration of fluids (such as water), fluxing (by light elements e.g. B, F, P etc) and more. These are all well established methods for magma formation, with an immense amount of evidence. This evidence includes independent observations from seismology, geochemistry, fluid mechanics, and probably most important - experimental simulation of these processes.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;it is generated from a catalytic reaction from massive interactions of water with large group 1 and group 2 metal pockets or clusters within the earth's crust.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;By &quot;metal pockets&quot; I mean that you mean metals with valence 0 - i.e. in the metallic state and not bound with other minerals. This is simply not true - especially for group 1 and 2 metals. These metals are highly reactive. Just search online for videos of &quot;&lt;a href=&quot;https://www.youtube.com/results?search_query=sodium%20party&quot; rel=&quot;nofollow noreferrer&quot;&gt;sodium party&lt;/a&gt;&quot;. The Earth's mantle has abundant oxygen in it (bound in silicates) and any group 1 or 2 metal will simply not exist as a metal. Even if for some obscure reason it would happen, where are the magmas containing these metal (more than they occur in magmas on a natural basis)? This simply doesn't make any sense.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;He further explained how the water enters into these pockets via&#xA;  various fissures both from our oceans and other bodies of water&#xA;  (noting some study from last year where researchers found incredible&#xA;  volumes of water 700 kilometers underground).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;First of all, the chemical and physical behaviour of water is completely different when you compare ocean floor settings and the deep mantle. Water may flow in fissures under the ocean, but once you get to several 10s of kilometres deep, the rocks become ductile and water can no longer flow in cracks and fissures. Regarding last year discovery of water in the mantle - this is really a sad story of poor science communication. What was actually discovered was that a certain mineral can contain water in its crystal structure. It's still a solid mineral and still a rock. Same like the water in concrete - it's not actually liquid water. See these two questions for more info:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/2137/what-are-the-implications-of-the-recent-discovery-that-huge-oceans-exist-close-t&quot;&gt;What are the implications of the recent discovery that huge oceans exist close to the mantle of the Earth?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/770/do-ringwoodite-minerals-point-to-an-oceans-worth-of-water-or-a-true-subterra&quot;&gt;Do ringwoodite minerals point to an &amp;quot;ocean&amp;#39;s worth&amp;quot; of water, or a true subterranean ocean?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;One side note was regarding the contents of magmatic rocks being surprisingly high in alkali metals, etc.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Most magmatic rocks contain a perfectly reasonable amounts of alkali metals. There are some rocks that have high alkali contents (and they have funny names too!), but this is not something that requires a different explanation from what is known so far from experiments and other studies. Yes, there are rocks with abnormally high alkali contents, and there is still research going on in that subject.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;but I was out of my depth &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I think this is the key word in here actually. Perhaps that professor was &quot;dumbing down&quot; his ideas to make it more accessible? This occasionally happens with us scientists, and in a lot of cases the listener simply understands something completely different from what the scientist meant. Another example of poor science communication, unfortunately.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-09-21T04:50:30.437" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4527" PostTypeId="1" AcceptedAnswerId="4540" CreationDate="2015-03-15T16:04:50.007" Score="3" ViewCount="1194" Body="&lt;p&gt;Studying for an exam tomorrow and stumped on this question (parts &lt;em&gt;d&lt;/em&gt; and &lt;em&gt;e&lt;/em&gt;).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The region show in Map 2 consists of a series of sedimentary strata&#xA;that have been tilted and then eroded, producing an unconformity. Lava&#xA;flows covered the unconformity, and the region underwent further&#xA;tilting and then faulting before erosion transformed the region in to&#xA;a plain.  Using the data provided by Map 2 determine&lt;/p&gt;&#xA;&lt;p&gt;a. amount of net slip&lt;/p&gt;&#xA;&lt;p&gt;b. rake of net slip on the fault plan&lt;/p&gt;&#xA;&lt;p&gt;c. plunge and trend of net slip&lt;/p&gt;&#xA;&lt;p&gt;d. relative movement along the fault e. type of fault&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/x9wMl.png&quot; alt=&quot;Map 2&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;The original answer for &lt;em&gt;d&lt;/em&gt; &amp;amp; &lt;em&gt;e&lt;/em&gt; was that the eastern block moved NW relative to the western block, and it was a sinistral reverse fault.  Can't remember why I chose reverse and not normal.&lt;/p&gt;&#xA;&lt;p&gt;Lab TA appears to be saying not sinistral, just 'normal'.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;So my questions are, how would you determine that it's a normal fault and not reverse?  Why not sinistral?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I can't see an indication of how the foot wall (western block) has moved relative to the hanging wall.  I know the TA is the person to ask but it's an online course and answers were slow to come at the best of times.&lt;/p&gt;&#xA;" OwnerUserId="1065" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-09-21T04:46:44.370" Title="How to determine if this fault is normal, sinistral?" Tags="|structural-geology|homework|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="4529" PostTypeId="1" CreationDate="2015-03-16T04:17:03.143" Score="5" ViewCount="2354" Body="&lt;p&gt;Has there ever been an incident in the U.S. where because of high gas prices people have driven their cars a lot less than usual for, say, many months, and after appropriate measurements it was determined that the ozone layer had less observable properties that might be considered 'damage'? If so, would it show if everyone switched to electric cars or some ‘gas alternative’ this could slowly 'repair' our atmosphere?&lt;/p&gt;&#xA;" OwnerUserId="1371" LastEditorUserId="1371" LastEditDate="2015-09-25T15:26:58.037" LastActivityDate="2015-09-25T15:26:58.037" Title="Has a reduction in car use ever had an effect on the ozone layer?" Tags="|pollution|gas|ozone|fossil-fuel|anthropocene|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="4530" PostTypeId="2" ParentId="4529" CreationDate="2015-03-16T09:32:25.477" Score="15" Body="&lt;p&gt;The sequence of events you describe has never happened, for several reasons.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;As Sabre Tooth mentions in the comments, vehicle emissions have a negligible effect on stratospheric ozone. (Note that while vehicle emissions can lead to ozone production at ground level, the ozone layer is several kilometres above the Earth's surface and isn't really affected by variation in ground-level ozone. The EPA has published a guide entitled &lt;a href=&quot;http://www.epa.gov/oar/oaqps/gooduphigh/&quot;&gt;&lt;em&gt;Ozone: good up high, bad nearby&lt;/em&gt;&lt;/a&gt; which explains the distinction in more detail.)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Even the most dramatic attempt to reduce driving in the USA, the National Maximum Speed Law of 1974, only produced a &lt;a href=&quot;http://en.wikipedia.org/wiki/National_Maximum_Speed_Law#Fuel_savings&quot;&gt;1% (or less) reduction in fuel consumption&lt;/a&gt;; we can assume that reductions in emissions would have been of similar magnitude.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Even in 1974, there were a lot of vehicles outside the USA, diluting the global impact of any changes in driving habits within the USA.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;However, to answer a slightly broader question, it does seem that the ozone layer is capable of repairing itself when emissions of ozone-depleting substances are reduced. &lt;a href=&quot;http://montreal-protocol.org/en/montreal_protocol.php&quot;&gt;The Montreal protocol&lt;/a&gt; was enacted in 1989:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Montreal Protocol on Substances that Deplete the Ozone Layer was designed to reduce the production and consumption of ozone depleting substances in order to reduce their abundance in the atmosphere, and thereby protect the earth's fragile ozone Layer. The original Montreal Protocol was agreed on 16 September 1987 and entered into force on 1 January 1989.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A &lt;a href=&quot;http://ozone.unep.org/Assessment_Panels/SAP/SAP2014_Assessment_for_Decision-Makers.pdf&quot;&gt;report released in 2014&lt;/a&gt; by the World Meteorological Organization concluded:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Actions taken under the Montreal Protocol have led to decreases in the atmospheric abundance of controlled ozone-depleting substances (ODSs), and are enabling the return of the ozone layer toward 1980 levels.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They estimate that total recovery will occur &quot;before midcentury in midlatitudes and the Arctic, and somewhat later for the Antarctic ozone hole&quot;.&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2015-03-16T18:30:34.780" LastActivityDate="2015-03-16T18:30:34.780" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="4531" PostTypeId="1" AcceptedAnswerId="4532" CreationDate="2015-03-16T15:14:26.917" Score="5" ViewCount="3022" Body="&lt;p&gt;I just got several well log curves, some of which are Thomsen's parameters. They are a result of interpretation of Sonic Scanner tool measurements (Schlumberger). Negative epsilon values appear quite frequently, which is not physical for VTI media (as far as I can conclude from books). Am I right?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question is not about measurements with a specific tool, but rather about the physical and geological interpretation of negative epsilon values. Gamma is also negative, by the way.&lt;/p&gt;&#xA;" OwnerUserId="506" LastEditorUserId="28050" LastEditDate="2015-03-16T18:26:06.763" LastActivityDate="2016-08-19T01:37:03.690" Title="Why can Thomsen's parameter $\epsilon$ be negative in VTI media?" Tags="|geophysics|seismology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4532" PostTypeId="2" ParentId="4531" CreationDate="2015-03-16T16:00:03.180" Score="7" Body="&lt;p&gt;&lt;strong&gt;Negative values are physical and are expected.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Indeed, &lt;a href=&quot;http://www.ime.unicamp.br/~amelia/mt860/thomsen.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Thomsen's 1986 paper&lt;/a&gt; has several negative values for $\delta$, $\epsilon$, and $\gamma$ — look at the data in Table 1. He also discusses negative values, at least for $\delta$ (e.g. on page 1961) . You can quickly get a sense of how common negative values are from his Figure 4:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/riCkx.png&quot; alt=&quot;Thomsen 1986, Figure 4, comparing anisotropy parameters.&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for physical meaning, it depends on the parameter. &lt;a href=&quot;http://www.agilegeoscience.com/blog/2015/2/9/what-is-anisotropy&quot; rel=&quot;nofollow noreferrer&quot;&gt;I recently wrote this&lt;/a&gt; about the physical meaning of the Thomsen parameters (edited for brevity): &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;$\delta$ or delta — the short offset effect — captures the&#xA;  relationship between the velocity required to flatten gathers (the NMO&#xA;  velocity) and the zero-offset average velocity as recorded by checkshots.&lt;/li&gt;&#xA;  &lt;li&gt;$\epsilon$ or epsilon — the long offset effect — is,&#xA;  according to Thomsen himself:  &quot;the fractional difference between&#xA;  vertical and horizontal P velocities; i.e., it is the parameter&#xA;  usually referred to as 'the' anisotropy of a rock&quot;.&lt;/li&gt;&#xA;  &lt;li&gt;$\gamma$ or gamma — the shear wave effect — relates, as rock physics&#xA;  meister Colin Sayers put it on Twitter, a horizontal shear wave with&#xA;  horizontal polarization to a vertical shear wave.&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Usually these parameters are, at a gross scale anyway, positive, because usually velocity is faster along bedding (roughly horizontally) than across it (roughly vertically). But it's easy to imagine scenarios where the relationship is reversed, especially if we're talking about small scales — as in log measurements.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Intuitively, we can draw these conclusions about negative parameters:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A rock with $\delta &amp;lt; 0$ has the zero-offset reflections 'seeing' &lt;em&gt;faster&lt;/em&gt; velocities than the long-offset reflections.&lt;/li&gt;&#xA;&lt;li&gt;A rock with $\epsilon &amp;lt; 0$ has a faster vertical velocity than horizontal velocity.&lt;/li&gt;&#xA;&lt;li&gt;A rock with $\gamma &amp;lt; 0$ has a faster vertical shear velocity than horizontal shear velocity.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thomsen, L (1986). Weak elastic anisotropy. &lt;em&gt;Geophysics&lt;/em&gt; &lt;strong&gt;51&lt;/strong&gt; (10), 1954–1966. &lt;a href=&quot;http://dx.doi.org/10.1190/1.1442051&quot; rel=&quot;nofollow noreferrer&quot;&gt;DOI 10.1190/1.1442051.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-03-16T16:00:03.180" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4533" PostTypeId="2" ParentId="4500" CreationDate="2015-03-16T16:17:59.533" Score="4" Body="&lt;p&gt;In remote sensing you often do not directly measure the variable of interest, i.e., you measure it via some other variable that you can measure (depending on the type of instrumentation). The model function is simply the function which relates the observed variable to the variable of interest, just like y=f(x).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;E.g., y could be wind speed, and x the energy measured by the scatterometer.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2015-03-16T17:54:02.413" LastActivityDate="2015-03-16T17:54:02.413" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4534" PostTypeId="2" ParentId="4520" CreationDate="2015-03-17T00:23:59.773" Score="1" Body="&lt;p&gt;When performing &quot;imaging&quot; we are generally attempting to recover the reflectivity of the earth.  At zero offset the reflectivity is the &lt;em&gt;difference&lt;/em&gt; in Acoustic Impedance (AI) normalized by the sum. When performing colored inversion we are seeking to recover a layered representation of the band limited AI and not the reflectivity.  As we go from an AI log to a reflectivity log by differentiating we need to integrate to go the other way.  In the frequency domain integration is a -90 degree phase term and an amplitude weight term.  The amplitude term (1/freq) is taken care of when matching the spectra to that of the well log in the amplitude term.&lt;/p&gt;&#xA;" OwnerUserId="2677" LastEditorUserId="725" LastEditDate="2016-09-21T04:48:32.587" LastActivityDate="2016-09-21T04:48:32.587" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4535" PostTypeId="1" CreationDate="2015-03-17T01:39:21.853" Score="5" ViewCount="3661" Body="&lt;p&gt;Would life on Earth survive if Sun wasn't there? My teacher told me that there are chances that it would but there would be a lack of gases and chemicals and photosynthesis that occurs with light at certain wavelength.&lt;/p&gt;&#xA;" OwnerUserId="2678" LastEditorUserId="192" LastEditDate="2015-03-22T23:04:09.447" LastActivityDate="2015-10-16T14:50:42.157" Title="Would life on Earth survive without the Sun?" Tags="|planetary-science|hypothetical|earth-system|" AnswerCount="6" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4536" PostTypeId="2" ParentId="4535" CreationDate="2015-03-17T02:14:38.327" Score="8" Body="&lt;p&gt;The Earth is as it currently is and has been since most of the Phanerozoic (542 Ma), the Eon of life, because of some important (not exhaustive) characteristics presented here, being:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;its inclination (causes seasons)&lt;/li&gt;&#xA;&lt;li&gt;its mass (gravity)&lt;/li&gt;&#xA;&lt;li&gt;its rotation (regulate a temperate climate)&lt;/li&gt;&#xA;&lt;li&gt;its revolution trajectory around the sun (latitudinal seasonality)&lt;/li&gt;&#xA;&lt;li&gt;its internal thermal regime (from the core) - tectonics, heat&lt;/li&gt;&#xA;&lt;li&gt;its distance from the sun (abundant water can easily exist in 3 phases)&lt;/li&gt;&#xA;&lt;li&gt;the sun's temperature&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;without the sun, temperature will be less than minus 230 °C (like on Pluton - let's be optimistic). A lot of essential things will be missing for it to be a dynamic system. It will be a frozen planet. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Microbes and virus should be fine.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Regarding photosynthesis especially.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Put simply, &lt;a href=&quot;https://www.msu.edu/user/morleyti/sun/Biology/photochem.html&quot;&gt;the photosynthesis balanced equation is&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;6CO&lt;sub&gt;2&lt;/sub&gt; + 6H&lt;sub&gt;2&lt;/sub&gt;O + Sunlight energy ------&gt; C&lt;sub&gt;6&lt;/sub&gt;H&lt;sub&gt;12&lt;/sub&gt;O&lt;sub&gt;6&lt;/sub&gt; + 6O&lt;sub&gt;2&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So let's remove the sun and consider the planet as totally frozen, the photosynthesis equation could hardly be balanced because several terms would not be relevant in the first place, such as the lack of available water, and the absence of light and heat for the process to occur:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;6CO&lt;sub&gt;2&lt;/sub&gt; + &lt;s&gt;6H&lt;sub&gt;2&lt;/sub&gt;O&lt;/s&gt; + &lt;s&gt;Sunlight energy&lt;/s&gt; ------&gt; doesn't work&lt;/p&gt;&#xA;" OwnerUserId="1411" LastEditorUserId="1411" LastEditDate="2015-03-17T12:47:02.597" LastActivityDate="2015-03-17T12:47:02.597" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4538" PostTypeId="2" ParentId="4535" CreationDate="2015-03-17T12:28:53.533" Score="12" Body="&lt;p&gt;The answer is &lt;strong&gt;No&lt;/strong&gt;, the Earth would not remain in any recognizable form without the Sun.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There would still be a husk of a dead planet with a small amount of energy coming from the residual heat of the core which might be able to sustain &lt;a href=&quot;http://en.wikipedia.org/wiki/Chemosynthesis&quot;&gt;chemosynthetic&lt;/a&gt; life in small colonies.  However, this is a pretty minor amount of energy compared to what we usually receive from the sun, and without an energy input lifeforms aren't able to sustain their unusually low &lt;a href=&quot;http://en.wikipedia.org/wiki/Entropy&quot;&gt;entropic&lt;/a&gt; state (i.e. entropy wins the battle with life).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some other examples of everyday things which would no longer occur (some already mentioned by @fre0n) are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;There would be no seasons.&lt;/li&gt;&#xA;&lt;li&gt;There would be no weather. &lt;/li&gt;&#xA;&lt;li&gt;There would be no daytime.&lt;/li&gt;&#xA;&lt;li&gt;There would be no liquid water at the surface.&lt;/li&gt;&#xA;&lt;li&gt;The surface temperature would drop to near &lt;a href=&quot;http://en.wikipedia.org/wiki/Absolute_zero&quot;&gt;absolute zero&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="53" LastActivityDate="2015-03-17T12:28:53.533" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4539" PostTypeId="2" ParentId="2546" CreationDate="2015-03-17T17:19:26.187" Score="4" Body="&lt;p&gt;Dry down is mainly dependent on the speed where a local water storage would be depleted, considering those components extracted from the simplified water balance equation&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;water input (precipitation)&lt;/li&gt;&#xA;&lt;li&gt;local drainage capacity (runoff, infiltration, percolation)&lt;/li&gt;&#xA;&lt;li&gt;evapotranspiration&lt;/li&gt;&#xA;&lt;li&gt;storage change and capacity (pores in the rock and soil)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;To generalize your question &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;is it relevant how much rain happened before the event?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I would say yes, as all input / output and potential changes in the storage need to be taken into account to calculate the balance, and ultimately the moment of depletion of the reservoir and thus the beginning of the dry-down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Antecedent conditions are of an utmost importance when estimating a dry down moment.If the storage was relatively empty prior to a rain event, it could take a lot of input to recharge it, this without neglecting the other factors. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To translate as an example, a huge rain event when the reservoir was empty prior to the event could recharge the reservoir and provide some surface runoff. A similar rain event when the reservoir was half-full prior would recharge for a while and then flood the area because of the important water excess.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is dependent on the climatic zone (ex &lt;a href=&quot;http://www.physicalgeography.net/fundamentals/7v.html&quot; rel=&quot;nofollow&quot;&gt;Köppen classification&lt;/a&gt;), say a warm and dry desert region will have a quite different balance than a polar region, because various input sources and different underground geophysical properties. Yet, within each regions, much variability will be encountered locally, depending on&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the ground/soil porosity (sands or weathered rocks can store more water. A clay layer will prevent downward infiltration)&lt;/li&gt;&#xA;&lt;li&gt;the presence/absence of vegetation (vegetation facilitate percolation/infiltration)&lt;/li&gt;&#xA;&lt;li&gt;the temperature of the soil : permafrost hydrology is quite complex - generally cold permafrost have a poor drainage capability&lt;/li&gt;&#xA;&lt;li&gt;maybe a floodplain will contribute to ground recharge one year, but maybe not the next, depending on the current year precipitations and antecedent conditions&lt;/li&gt;&#xA;&lt;li&gt;plus many other factors etc...&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;It may be possible at the scale of a single watershed to do a prediction model on the probable schedule of a dry down - or a restricted land unit, because a lot of drilling and geophysical all around surveys would be necessary to know the ground properties, the storage properties. Also a couple of monitoring station (discharge) at &lt;a href=&quot;http://en.wikipedia.org/wiki/Strahler_number&quot; rel=&quot;nofollow&quot;&gt;higher stream order segments&lt;/a&gt; would be required. Rain meters stations too. Moisture would be monitored in representative ground units.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But this would apply locally, and be hardly exportable at a larger scale, in my opinion. I would go with this statement of yours:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Or is it all arbitrary and defined differently for each individual piece of research?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;yes generally&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2015-03-17T17:19:26.187" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4540" PostTypeId="2" ParentId="4527" CreationDate="2015-03-17T23:27:22.460" Score="3" Body="&lt;p&gt;So, the basic geological history is given. From this, the units named Bed 1, were deposited, then tilted. Bed 2 was deposited and tilted (along with Bed 1). The entire sequence was then faulted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, how can we tell what the fault did?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First of all, notice that there was movement of the eastern block to the north-west. This can be deduced because all the contacts have been shifted in that direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, let us undo that shift to the north-west:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://dl.dropboxusercontent.com/u/17444491/geology/x9wMl_2.png&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, we can see that the contact between Bed 2 and Bed 1 does not line up. This means that we must have had movement up or down as well. The only way to work this one out is by knowing which way the contact dips. If it dips northwards, then the eastern block moved up. If it dipped south, then it would overlie all the sediments to the south. This suggests that Bed 2 dips northwards.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Upward movement of the eastern block would then reveal Bed 1 when the area was eroded.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My conclusion therefore, is that the fault moved the eastern block north-west and up, relative to the western block.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Did I miss anything? It is late, which I will claim as an excuse. If my logic is unclear, let me know and I can try add more pictures, or video of me waving hands about, which is my usual approach.&lt;/p&gt;&#xA;" OwnerUserId="2514" LastActivityDate="2015-03-17T23:27:22.460" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4541" PostTypeId="1" CreationDate="2015-03-18T04:51:28.603" Score="8" ViewCount="2819" Body="&lt;p&gt;As we know the mixed phase data would not give the &quot;real TWTT&quot; through the medium. We need a zero-phase wavelet that can directly correspond to the time taken to travel in a given media. So my question is how do we convert the seismic trace wavelet to zero phase which is in mixed phase? There must be an important processing procedure to do so. &lt;/p&gt;&#xA;" OwnerUserId="2662" LastActivityDate="2016-02-28T00:05:09.820" Title="How do we convert the seismic trace wavelet to zero phase which is in mixed phase?" Tags="|geophysics|inversion|wave-modeling|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4542" PostTypeId="1" AcceptedAnswerId="4546" CreationDate="2015-03-18T06:48:33.477" Score="7" ViewCount="188" Body="&lt;p&gt;In the northern part of Queensland, Cyclone Nathan has had a spiral type of track, as can be seen below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/CGj2A.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Image credit: Tropical Cyclone NATHAN Forecast Track (Joint Typhoon Warning Center)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As can be seen in the diagram, it tracked in from the Coral Sea, stopped short of making landfall on the Cape York Peninsula, went back out to sea and has tracked back inland  -and is expected to make landfall and cross into the Gulf of Carpentaria (where it may re-intensify).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What meteorological mechanisms would cause the spiraling track of a cyclone?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2015-03-18T17:44:25.227" Title="The spiraling cyclone track - Cyclone Nathan" Tags="|meteorology|tropical-cyclone|severe-weather|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4543" PostTypeId="5" CreationDate="2015-03-18T14:13:36.093" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2015-03-18T14:13:36.093" LastActivityDate="2015-03-18T14:13:36.093" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4544" PostTypeId="4" CreationDate="2015-03-18T14:13:36.093" Score="0" Body="The Dust Bowl was a series of huge storms of dirt and dust that swept across America in the 1930's that were caused by a combination of drought and bad farming practices." OwnerUserId="115" LastEditorUserId="115" LastEditDate="2015-03-18T17:44:49.820" LastActivityDate="2015-03-18T17:44:49.820" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4546" PostTypeId="2" ParentId="4542" CreationDate="2015-03-18T17:44:25.227" Score="7" Body="&lt;p&gt;Hurricanes backtracking and looping seem to be quite common in the Atlantic (&lt;a href=&quot;http://weather.unisys.com/hurricane/atlantic/2012H/NADINE/track.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nadine&lt;/a&gt;, &lt;a href=&quot;http://weather.unisys.com/hurricane/atlantic/2004H/JEANNE/track.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;Jeanne&lt;/a&gt;, &lt;a href=&quot;http://weather.unisys.com/hurricane/atlantic/2000H/ALBERTO/track.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;Alberto&lt;/a&gt;, &lt;a href=&quot;http://weather.unisys.com/hurricane/atlantic/1999H/DENNIS/track.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dennis&lt;/a&gt;), and West Pacific (&lt;a href=&quot;http://weather.unisys.com/hurricane/w_pacific/1996H/ERNIE/track.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ernie&lt;/a&gt;, &lt;a href=&quot;http://weather.unisys.com/hurricane/w_pacific/2001H/NARI/track.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nari&lt;/a&gt;, &lt;a href=&quot;http://weather.unisys.com/hurricane/w_pacific/2002H/FUNG_WONG/track.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fung Wong&lt;/a&gt;, &lt;a href=&quot;http://weather.unisys.com/hurricane/w_pacific/2003H/PARMA/track.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;Parma&lt;/a&gt;, &lt;a href=&quot;http://weather.unisys.com/hurricane/w_pacific/2011H/ROKE/track.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;Roke&lt;/a&gt;) but not so much in the East Pacific (where the tracks are way more linear, with much less latitudinal change).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, tropical cyclones are steered by the global wind field. The environmental wind field (winds that surround a hurricane) guides a cyclone along its path. Hurricanes are steered predominantly by winds in the upper atmosphere, especially winds from about 3000 to 10000 meters above sea level. High-pressure and low-pressure systems often cause cyclones to divert from their initially east-to-west movement. When a high- or low-pressure system is located to the west and extends far enough latitudinally, storms are blocked and a change in direction may occur. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case of Tropical Cyclone Nathan, there seems to have been a stationary &lt;a href=&quot;http://www.bom.gov.au/australia/charts/synoptic_col.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;high over southwestern Australia&lt;/a&gt; on 12 March 2015 that connected with another high to the north and prevented the movement of the cyclone. The presence of Tropical Cyclones Olwyn and Pam probably influenced the change in path.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/h4SEk.jpg&quot; alt=&quot;three cyclones&quot;&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nathan started to move north as Pam was moving south (13 March) and then went east without that much obstruction (14-15 March). As the high pressure to the south moved east, there was a clear path for Nathan to continue moving west (18-March).&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-03-18T17:44:25.227" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4547" PostTypeId="1" AcceptedAnswerId="4550" CreationDate="2015-03-19T04:40:30.993" Score="5" ViewCount="605" Body="&lt;p&gt;The Maylaysian jetliner that went missing has yet to be found. There are many remote sensing satellites, equipped with radars, currently in service. Together, they provide good coverage of the entire Earth. Why is it their data could not be used effectively in tracking down the path of an airplane? If the airplane lands on the ocean, shouldn't we be able to tell from satellite data?&lt;/p&gt;&#xA;" OwnerUserId="2645" LastActivityDate="2015-03-19T11:52:06.123" Title="Locating Missing Airplanes using Remote-Sensing Satellites" Tags="|remote-sensing|satellites|" AnswerCount="1" CommentCount="5" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4548" PostTypeId="2" ParentId="2706" CreationDate="2015-03-19T09:30:35.223" Score="0" Body="&lt;p&gt;Assuming there is spatial correlation between the data points, the interpolation can be done using &lt;a href=&quot;http://en.wikipedia.org/wiki/Kriging&quot; rel=&quot;nofollow&quot;&gt;ordinary Kriging&lt;/a&gt; or another variant of the method. &lt;/p&gt;&#xA;" OwnerUserId="2684" LastActivityDate="2015-03-19T09:30:35.223" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4549" PostTypeId="2" ParentId="4467" CreationDate="2015-03-19T10:39:06.793" Score="6" Body="&lt;p&gt;&lt;em&gt;This answer seeks to just answer about ambient air entrainment, as per the question (not eruptive plume height, as suggested in the comments) which is a separate question.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the book, &lt;em&gt;Modeling Volcanic Processes: The Physics and Mathematics of Volcanism, (Fagents et al, 2012, p. 155-156)&lt;/em&gt;, your assumption (2nd paragraph) is on the right track, particularly for energetic eruptions (e.g. Plinian).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the plume initially erupts, it possesses significant momentum, with a greater density and are influenced by pressures considerably greater than the ambient atmosphere.  However, once in the atmosphere, the plume undergoes rapid decompression and expands, ascending as a turbulent flow in the &lt;em&gt;convective ascent region&lt;/em&gt; (an example is shown below).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/8DcsA.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Image source: USGS page about the &lt;a href=&quot;http://volcanoes.usgs.gov/volcanoes/st_helens/st_helens_geo_hist_99.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mt St Helens eruption in 1980&lt;/a&gt;&lt;/em&gt; demonstrating the turbulence in an eruptive column.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the flow continues to ascend, the eruptive column begins to exhibit lateral gradients in temperature, momentum and density, allowing for the mixing with the ambient air at the edges of the column - over time, this mixing continues to the core of the eruptive column by shear mixing.  Effectively, 'stirred into the column by the turbulence'.(Fagents et al. 2012; Kaminski et al. 2011).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/UtkBV.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Image source: &lt;a href=&quot;http://www.geo.mtu.edu/~raman/VBigIdeas/VolcClouds.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;MTU.edu&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the entrained air heats, expands and rises, more cooler ambient air is mixed into the turbulent eruptive column (just as long as the eruption continues) - as per the MTU.edu diagram above, the plume rises by buoyant convection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Entrainment of air into the eruptive column can be increased by the right wind conditions, as observed at the 2011 Kirishima-Shinmoe-dake volcano eruption in Japan (Kozono et al. 2014).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Additional resources&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kozono et al. 2014, &lt;a href=&quot;http://link.springer.com/article/10.1186/s40623-014-0139-1/fulltext.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Correlation between magma chamber deflation and eruption cloud height during the 2011 Shinmoe-dake eruptions&lt;/a&gt;, &lt;em&gt;Earth, Planets and Space&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kaminski et al. 2011, &lt;a href=&quot;http://www.ipgp.fr/~kaminski/web_doudoud/ConvPenet.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rise of volcanic plumes to the stratosphere aided by penetrative convection above&#xA;large lava flows&lt;/a&gt;, &lt;em&gt;Earth and Planetary Science Letters&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-03-19T17:55:18.577" LastActivityDate="2015-03-19T17:55:18.577" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4550" PostTypeId="2" ParentId="4547" CreationDate="2015-03-19T11:42:36.117" Score="10" Body="&lt;p&gt;Civilian earth observing SAR satellites do not always operate over empty swaths of oceans (specially in the middle of Indian Ocean) in order to save power. They are not designed to track a fast moving target and have repeat cycle of at least a few days. Then there is the issue of resolution. High res acquisitions modes (with satellites like TerraSAR-X) are pre-programmed in advance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in theory it is possible that a flying aircraft might show up in the amplitude image (a pixel or two wide) if a satellite was indeed flying over the Indian ocean and acquiring data over the area where the plane was flying. But then all you have is a single image. And once the plane is under water you wont see anything.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2015-03-19T11:52:06.123" LastActivityDate="2015-03-19T11:52:06.123" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4551" PostTypeId="2" ParentId="2706" CreationDate="2015-03-19T13:29:20.510" Score="7" Body="&lt;p&gt;Welcome to an interesting and important field of research!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Interpolation is a large topic and there are many techniques. I agree that the GIS or math forum could be more initiated, but for completeness, I'll post some thoughts here. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The choice of method depends on the type of data you are using and the implementation depends on your environment. GIS software should always have a number of methods and parameters to adjust. It's also rather easy to create a script in e.g python or matlab to test and evaluate interpolation methods (&lt;a href=&quot;http://docs.scipy.org/doc/scipy/reference/tutorial/interpolate.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;E.g this&lt;/a&gt;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some questions to answer before you chose your method are:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Can I trust all my data? How much noise do I have?&lt;/li&gt;&#xA;&lt;li&gt;Should only the nearest points be considered for the interpolation? How far should I 'feel' the values from data points?&lt;/li&gt;&#xA;&lt;li&gt;How many dimensions should be interpolated? E.g. should I take time  into consideration?&lt;/li&gt;&#xA;&lt;li&gt;Should the curves be as smooth as possible? &lt;/li&gt;&#xA;&lt;li&gt;Should all interpolated values be in a specific range, within min-max of the whole data set or between the nearest points? &lt;/li&gt;&#xA;&lt;li&gt;Do I know the total value? E.g. when interpolating population density I might know the total population and this could help me find the right interpolation method. &lt;/li&gt;&#xA;&lt;li&gt;Process speed, that is an issue in your case might force you to choose a simpler technique. &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Multivariate_interpolation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia has an overview&lt;/a&gt; and &lt;a href=&quot;http://ac.els-cdn.com/S0898122198001011/1-s2.0-S0898122198001011-main.pdf?_tid=d52e5218-ce37-11e4-b27f-00000aab0f01&amp;amp;acdnat=1426770172_921a1b467e4151ea5ffb2ce014eb881c&quot; rel=&quot;nofollow noreferrer&quot;&gt;Caruso, C., and F. Quarta. &quot;Interpolation methods comparison.&quot;&lt;/a&gt; Gives a rather good introduction of the techniques and there are some good webpages on GIS and interpolation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most important step is to test the method you choose. Again, there are various ways to do so, but the easiest is to simply leave points out from you data set and interpolate the values without them. Try to make the interpolated value as &lt;a href=&quot;http://en.wikipedia.org/wiki/Mean_squared_error&quot; rel=&quot;nofollow noreferrer&quot;&gt;close&lt;/a&gt; to the data value as possible. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Kriging&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kriging&lt;/a&gt; are methods based on the actual data instead of a curve. It's often a good first try on spatial data but also in other application &lt;a href=&quot;http://people.ku.edu/~gbohling/cpe940/Kriging.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;like this&lt;/a&gt;.&#xA;&lt;a href=&quot;http://en.wikipedia.org/wiki/Smoothing_spline&quot; rel=&quot;nofollow noreferrer&quot;&gt;Spline&lt;/a&gt; methods produces smoother curves. People doing computer graphics are experts on this, but there can also be applications where you'll aspect smooth changes in a model. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Naturally, more complex methods (e.g. kriging) take longer time to process, whiles simpler algorithms (e.g. bilinear or nearest-neighbor) are faster. Lower resolution of your output raster (array) would also speed up the process. You can let your resolution depend on the variance of the data, so that you interpolate less points in a flat surface and more points for a surface with higher relief. This techniques are common practice in signal processing and the experts are &lt;a href=&quot;https://dsp.stackexchange.com/&quot;&gt;here&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="-1" LastEditDate="2017-04-13T12:47:30.010" LastActivityDate="2015-03-20T11:08:47.587" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4552" PostTypeId="2" ParentId="2706" CreationDate="2015-03-19T13:31:08.543" Score="6" Body="&lt;p&gt;A good place to looking is &lt;a href=&quot;https://en.wikipedia.org/wiki/Geostatistics&quot;&gt;geostatistics&lt;/a&gt;.  It is a branch of statistics focusing on spatial or spatiotemporal datasets. In its earlier days, geostatistics was also known as the theory of regionalized variables.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geostatistics was initially developed by &lt;a href=&quot;http://en.wikipedia.org/wiki/Georges_Matheron&quot;&gt;George Matheron&lt;/a&gt;, a French mathematician and geologist - though when I first heard about him in the 1980s he was described as a mining engineer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Matheron developed geostatistics to find a better way to determined ore reserves more accurately. His other other aim was to try to ascertain a level of accuracy for ore reserves (i.e x ounces of gold at a confidence of y %) . Since the initial development of geostatistics in the 1960s for ore reserves in mining, the technique has been used in other fields where there is a spatial co-relation between data samples, such a forestry, pollution contamination around metal smelters, soil science, geochemistry, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the key tools of geostatistics is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Variogram&quot;&gt;variogram&lt;/a&gt;. The variogram is used to determine the distance at which samples can be regarded as being independent of each other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mathematics for variograms can look bewildering, but variograms can be explained simply. Consider a line of 100 equally spaced sample points, say 1 metre apart.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Determine the variance for all data points 1 m apart, i.e 1 &amp;amp; 2, 2 &amp;amp;&#xA;3, ... 19 &amp;amp; 20 ...&lt;/li&gt;&#xA;&lt;li&gt;Next calculate the variance for all points 2 m apart: 1 &amp;amp; 3, 3 &amp;amp; 5,&#xA;... 17 &amp;amp; 19, also 2 &amp;amp; 4, 4 &amp;amp; 6, ... 18 &amp;amp; 20 ...&lt;/li&gt;&#xA;&lt;li&gt;Then find the variance for samples 4 m apart and then 5 m apart and&#xA;10 m, 20 m, 25 m and 50 m&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The sample distances must be factors of the total distance. You can find the variance for samples 3 m apart because 3 doesn't divide into 100 evenly, but if there were only 99 samples then things are totally different.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The distance between samples is known as the lag distance. On a plot of variance versus lag distance, for low lag values the curve will rise. Where the curve flatten out is the distance at which samples can be regarded as being independent of each other. The variogram has its roots in the &lt;a href=&quot;http://www.aaec.ttu.edu/faculty/eelam/3401/CourseMaterials/Notes_Fall07/Notes_Regr1_Elam08-31-07.pdf&quot;&gt;correlation diagrams&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For data on a 2D grid, it is prudent to obtain a suite of variograms along the directions north-south, east-west, northwest-southeast and northeast-southwest to obtain an initial variance rosette. Any trend in the data will be seen from this and a better variogram orientation can then be tried.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where the distance between samples is strictly not uniform, but within accepted tolerances, adjustments will need to be made to the data. Also if data is clustered within areas, the data will need to be declustered first.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When data points are being considered it is common for a search ellipse to be used and for the search ellipse to be orientated. For example, is the data set is soil contamination samples around a metal smelter, or seed dispersal from trees, the search ellipse would be orientated so the major axis would be aligned with the direction of the prevailing winds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because of the amount of calculations involved and the size of some data set, particularly metal grades in geological ore bodies, computers are heavily involved with geostatistical analyses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An initial reference on geostatistics is &lt;a href=&quot;http://www.kriging.com/pg1979_download.html&quot;&gt;Isobel Clark, 1979, Practical Geostatistics, Applied Science Publishers&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to estimate a value between sample points then either some form of weighting of samples will need to be used. Within geostatistics, &lt;a href=&quot;http://www.kriging.com/whatiskriging.html&quot;&gt;kriging&lt;/a&gt; is usually used, but there are many forms of kriging, just to name a few: ordinary, disjunctive, log-normal, indicator. What some people also do is to use other forms of weighting such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Inverse_distance_weighting&quot;&gt;inverse distance&lt;/a&gt; squared, or &lt;a href=&quot;https://www.rockware.com/rockworks/help/solid_model_inverse.htm&quot;&gt;inverse distance&lt;/a&gt; to another power, usually between 1.5 and 3, but inverse distance squared is the more common of these. The results from kriging and inverse distance squared are then compared. The two techniques will rarely give the same results, but the results should be similar.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-03-19T13:31:08.543" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4553" PostTypeId="1" AcceptedAnswerId="4554" CreationDate="2015-03-20T01:02:20.640" Score="8" ViewCount="783" Body="&lt;p&gt;Is there a good dataset on global ocean sea surface height? I found this, &lt;a href=&quot;http://climate.nasa.gov/interactives/sea_level_viewer&quot;&gt;http://climate.nasa.gov/interactives/sea_level_viewer&lt;/a&gt;, but there is no data I can download and it's hard to see the latitude and longitude coordinates.&lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorUserId="111" LastEditDate="2015-03-20T01:36:24.493" LastActivityDate="2018-02-03T09:13:50.407" Title="Sea Surface Height Data" Tags="|ocean|oceanography|sea-level|open-data|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4554" PostTypeId="2" ParentId="4553" CreationDate="2015-03-20T01:18:06.457" Score="7" Body="&lt;p&gt;The easiest global sea surface height database is from Aviso: &lt;a href=&quot;http://www.aviso.oceanobs.com/en/data/products/sea-surface-height-products/global.html&quot;&gt;http://www.aviso.oceanobs.com/en/data/products/sea-surface-height-products/global.html&lt;/a&gt;&#xA;Aviso has been distributing Topex/Poseidon and ERS altimetric data worldwide since 1992.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-03-20T01:18:06.457" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4555" PostTypeId="1" AcceptedAnswerId="4558" CreationDate="2015-03-20T07:02:41.070" Score="10" ViewCount="958" Body="&lt;p&gt;Here is a map of ocean surface height or topography:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/IziKc.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2010/12/mean_dynamic_topography_of_global_ocean/9930795-2-eng-GB/Mean_dynamic_topography_of_global_ocean.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.esa.int/var/esa/storage/images/esa_multimedia/images/2010/12/mean_dynamic_topography_of_global_ocean/9930795-2-eng-GB/Mean_dynamic_topography_of_global_ocean.jpg&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How significant is the bathymetry or seabed elevation in shaping the surface topography? What are the major causes of variations in the topography?&lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorUserId="111" LastEditDate="2015-03-23T01:26:31.983" LastActivityDate="2015-03-23T01:26:31.983" Title="Does bathymetry affect ocean topography/height?" Tags="|ocean|ocean-currents|sea-level|topography|bathymetry|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="4556" PostTypeId="2" ParentId="4511" CreationDate="2015-03-20T12:04:42.923" Score="12" Body="&lt;p&gt;The probability of precipitation is most likely to mean the proportion of models in an ensemble or weather models in which precipitation was observed at a particular location over a particular time period.&lt;/p&gt;&#xA;&lt;p&gt;If you want to work out the probability of it raining during the day, the best approach would be to work out one minus the probability that there was no rain in hour one and there was no rain in hour two and there was no rain in hour three...  Mathematically if &lt;span class=&quot;math-container&quot;&gt;$x_i$&lt;/span&gt; represents the presence or absence of rain in hour &lt;span class=&quot;math-container&quot;&gt;$i$&lt;/span&gt;, then&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$P(rain) = 1 - \prod_{i=1}^{24} (1 - P(x_i = 1))$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, this assumes that the probabilities of rain in each hour are independent, which is unlikely to be true.  To deal with this, we would need to introduce conditional probabilities (which are not supplied by the forecast), i.e.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$P(rain) = 1 - (1 - p(x_1=1)\times(1 - p(x_2=1|x_1))\times(1 - p(x_3=1|x_1,x_2))\times \cdot \times(1 - p(x_{24}=1|x_1,x_2,\ldots,x_{22},x_{23})$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;So unfortunately you will not be easily able to reconcile the daily and hourly probabilities as this would require the conditional probabilities (or at least a model of the dependence), which probably is not supplied in the forecast.&lt;/p&gt;&#xA;&lt;p&gt;In the particular example given in the question, if there were four hours that had a probability of rainfall of 50% then this could mean that 50 out of 100 models in the forecast ensemble had rain that lasted all four hours and the other 50 were dry.  However, it could have meant that 50 models have rain for the first two hours and dry after that, and the other fifty were dry for two hours and then had rain for two hours.  In the first case, the probability of there being rain at some point during the four hours is 50% (as half of the models say there will be no rain at any point) whereas in the second case, the chance of rainfall at some point will be 100% as all the models agree that it &lt;em&gt;will&lt;/em&gt; rain during the four hour period, they just disagree as to precisely when it will happen.  The daily forecast works this out by looking at the proportion of models that actually gave some precipitation at some point during the day, but the hourly probabilities in isolation don't give enough information to work out what happened throughout the day in individual model runs.&lt;/p&gt;&#xA;" OwnerUserId="624" LastEditorUserId="-1" LastEditDate="2020-07-11T09:14:42.623" LastActivityDate="2020-07-11T09:14:42.623" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="4557" PostTypeId="2" ParentId="2214" CreationDate="2015-03-20T13:52:55.133" Score="10" Body="&lt;p&gt;In a recent study, &lt;a href=&quot;http://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/viewArticle/1533/1715&quot;&gt;Talone et al. (2014)&lt;/a&gt; compare 4 different geoids and evaluate their effects for oceanographic studies. The four geoids they used are:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;&lt;p&gt;EGM96: The Earth Geopotential Model 1996 embodies ground-based as well as satellite measurements (Lemoine et al. 1998). Remotely sensed data were mainly radar altimeter observations, averaged and transformed in gravity anomalies as expressed in Sandwell and Smith (1997). This geoid may be downloaded from the National Aeronautics and Space Administration (NASA) Goddard Space Flight Center web page (&lt;a href=&quot;http://cddis.gsfc.nasa.gov/926/egm96/egm96.html&quot;&gt;http://cddis.gsfc.nasa.gov/926/egm96/egm96.html&lt;/a&gt;). In this study a 360-degree and -order version of the EGM96, included in the GOCE User Toolbox (GUT), was used. GUT is distributed by the ESA at &lt;a href=&quot;http://earth.esa.int/gut/&quot;&gt;http://earth.esa.int/gut/&lt;/a&gt;. In the spatial domain, the geoid is defined on a 0.5° uniform grid. Since the calculation of the EGM96 geoid included altimetry measurements, we may expect that it might have been influenced by some signal from the MSS fields.&lt;/p&gt;&lt;/li&gt;&#xA;  &lt;li&gt;&lt;p&gt;GRACE05: The Gravity Recovery and Climate Experiment (GRACE) (Tapley et al. 2004) is a joint mission by the American (NASA) and the German (DLR) space agencies, launched in March 2002 with the objective of making detailed measurements of the Earth’s gravity field. GRACE’s data are available on the web pages of these two institutions (&lt;a href=&quot;http://podaac.jpl.nasa.gov/grace&quot;&gt;http://podaac.jpl.nasa.gov/grace&lt;/a&gt; and &lt;a href=&quot;http://isdc.gfz-potsdam.de/grace&quot;&gt;http://isdc.gfz-potsdam.de/grace&lt;/a&gt;). As for EGM96, the GRACE05 geoid used in this study is included in the GUT (see Foerste et al. [2008]). It is characterized by a spatial resolution of 0.5° and a spherical harmonic degree and order 360. GRACE05, in the version used for this study, includes altimetry measurements.&lt;/p&gt;&lt;/li&gt;&#xA;  &lt;li&gt;&lt;p&gt;EGM2008: The Earth Gravitational Model 2008 is described in Pavlis et al. (2008) and distributed by the International Centre for Global Gravity Field Models (&lt;a href=&quot;http://icgem.gfz-potsdam.de/ICGEM/shms/egm2008.gfc&quot;&gt;http://icgem.gfz-potsdam.de/ICGEM/shms/egm2008.gfc&lt;/a&gt;). It is available up to spherical harmonic degree and order 2159, and contains additional coefficients extending to degree 2190 and order 2159. For consistency with the EGM96 and GRACE05, the geoid heights have been calculated using up to the spherical harmonic degree and order 360, with a spatial resolution of 0.5°. Like EGM96, EGM2008 is the outcome of fusing different data from several sources, including altimetry data.&lt;/p&gt;&lt;/li&gt;&#xA;  &lt;li&gt;&lt;p&gt;GOCE’s level 2 time-wise product: The time-wise product is obtained using only direct measurements of the gravity field, without any altimetry contribution. Details about the GOCE mission can be found on the ESA web page (&lt;a href=&quot;http://earth.esa.int/GOCE&quot;&gt;http://earth.esa.int/GOCE&lt;/a&gt;) and in the ESA (1999) report; data may be accessed on the ESA web page. Three different products are available, namely the direct solution, the space-wise solution and the time-wise solution; the last of these was used in this study as it does not rely on auxiliary information (EGG-C 2012). We used the third release, the last one available at the time of the study, based on 16 months of data collected over 18 months (from November 2009 to April 2011). The spatial resolution of the GOCE level 2 products is 0.5°, with degree and order 250.&lt;/p&gt;&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Talone, M., Meloni, M., Pelegri, J. L., Rosell-Fieschi, M., &amp;amp; Flobergaghen, R. (2014). Evolution of geoids in recent years and its impact on oceanography. Scientia Marina, 78(2), 155-164.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-03-20T13:52:55.133" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4558" PostTypeId="2" ParentId="4555" CreationDate="2015-03-20T14:27:27.457" Score="10" Body="&lt;p&gt;Oceanic topography of the sea surface $\zeta$ can be defined as the height of the sea surface relative to a particular level surface, the &lt;a href=&quot;http://en.wikipedia.org/wiki/Geoid&quot;&gt;geoid&lt;/a&gt;. The geoid to be the level surface that coincided with the surface of the ocean at rest (a list of geoids with application to oceanography can be found in &lt;a href=&quot;http://scientiamarina.revistas.csic.es/index.php/scientiamarina/article/view/1533/1715&quot;&gt;Talone et al., 2014&lt;/a&gt;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Variations in sea surface height (topography) are due to processes that result in ocean motion: ocean currents, tides, and changes in barometric pressure from the inverted barometer effect. As a result, we usually call it &quot;dynamic topography&quot; or &quot;dynamic height&quot;. As geoid undulations are of order 100 times larger than the dynamic height, the shape of the sea surface is dominated by local geoid variations caused by gravity with the effect of the currents being much smaller.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the image you provide what you have is &quot;dynamic height&quot; and thus is a deviation from the geoid and the result of oceanic currents. By knowing the dynamic height, we can get an idea of the surface geostrophic current:&#xA;$\mathrm{u_s= − {g\over f} {\delta\zeta\over\delta y}}$; $\mathrm{v_s= − {g\over f} { \delta\zeta\over\delta x}}$ where f is the Coriolis parameter,  g is gravity, and $\zeta$ is the height of the sea surface above the level surface (geoid).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, there is a direct effect between currents and bathymetry that sometimes is referred to as &lt;a href=&quot;http://en.wikipedia.org/wiki/Taylor_column&quot;&gt;Taylor columns&lt;/a&gt;. The &lt;a href=&quot;http://en.wikipedia.org/wiki/Taylor%E2%80%93Proudman_theorem&quot;&gt;Taylor-Proudman theorem&lt;/a&gt; enforces that vertical columns of fluid move along contours of constant fluid depth. The basic idea behind this is that in order to conserve vorticity, fluid parcels tend to follow bathymetric contours (isobaths). So to answer your question, bathymetry affects ocean topography indirectly by affecting ocean currents.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-03-20T14:27:27.457" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4559" PostTypeId="2" ParentId="4449" CreationDate="2015-03-20T18:23:53.553" Score="14" Body="&lt;p&gt;Meddies are anticyclonic (rotating clockwise) lenses of warm salty Mediterranean Water that travel through the North Atlantic between ∼500 and 1500 m depth. They are observed as large temperature, salinity and velocity anomalies &lt;a href=&quot;http://dx.doi.org/10.1016/S0079-6611(99)00053-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Richardson et al., 2000)&lt;/a&gt;. Meddies are typically 40–100 km in diameter with their core being 500–1000 m thick.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meddies separate from the Mediterranean Undercurrent (the main Mediterranean outflow) as it flows through abrupt topographic changes like major canyons. Each year between 15–20 meddies are formed off southern Portugal predominantly at two sites (&lt;a href=&quot;http://dx.doi.org/10.1175/1520-0485(1997)027%3C2545:LOOMFD%3E2.0.CO;2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bower et al., 1997&lt;/a&gt;): Cape St. Vincent (37° N) and Extremadura Promontory (39° N). They can be detected by their surface signature in surface temperature and sea level anomalies (&lt;a href=&quot;http://dx.doi.org/10.1016/S0422-9894(00)80008-2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oliveira et al., 2000&lt;/a&gt;). A large percentage of the meddies formed collide with large seamounts decay while some travel west on the north side of the seamounts and then travel southwest near Cape St Vincent toward the Canary basin with translation speeds of a few cm/s and clockwise rotation periods of 4 to 6 days &lt;a href=&quot;http://dx.doi.org/10.1016/S0079-6611(99)00053-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Richardson et al., 2000)&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/2b4wY.jpg&quot; alt=&quot;meddy location&quot;&gt;&lt;br /&gt;&#xA;&lt;sup&gt;(P.L. Richardson: &quot;Tracking Ocean Eddies&quot;, American Scientist 81, 261--271, 1993. Fig 10. &lt;a href=&quot;http://josvg.home.xs4all.nl/Dundee/meddies/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://josvg.home.xs4all.nl/Dundee/meddies/index.html&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meddies can have maximum salinities around 36.5 and maximum temperatures around 13°C and they are observed as large anomalies (salinity anomaly ~1 and temperature anomaly ~4 °C) as they travel westward into cooler and fresher water. During their trip, the Mediterranean water inside the meddy slowly mixes with the surrounding Atlantic water and the salt anomaly progressively weakens until the meddy dissipates. The main processes causing mixing occur at the boundary of a meddy where the largest gradients of temperature and salinity exist and are double-diffusion and thermohaline intrusions as large as 25 m thick (&lt;a href=&quot;http://dx.doi.org/10.1175/JPO-D-14-0061.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Meunier et al., 2015&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/zY3tt.jpg&quot; alt=&quot;temp/sal&quot;&gt;&lt;br /&gt;&#xA;&lt;sup&gt;From Tychensky et Carton, 1998. (&lt;a href=&quot;http://outreach.eurosites.info/outreach/DeepOceans/station.php?id=10&amp;amp;page_inc=fact&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://outreach.eurosites.info/outreach/DeepOceans/station.php?id=10&amp;amp;page_inc=fact&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meddies average lifespan is around 1.7 years although some were observed for more than 5 years &lt;a href=&quot;http://dx.doi.org/10.1016/S0079-6611(99)00053-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Richardson et al., 2000)&lt;/a&gt;. During that time they travel distances up to one thousand kilometers and their maintained mostly because the core of the meddy tends to have a doubly-stable stratification (&lt;a href=&quot;http://dx.doi.org/10.1175/1520-0485(1989)019%3C0354:TYITLO%3E2.0.CO;2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Armi et al., 1989&lt;/a&gt;). Up to 29 meddies may coexist in the North Atlantic at the same time &lt;a href=&quot;http://dx.doi.org/10.1016/S0079-6611(99)00053-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Richardson et al., 2000)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/1xnMV.jpg&quot; alt=&quot;spatial&quot;&gt;&lt;br /&gt;&#xA;&lt;sup&gt;From Univ. of Delaware (&lt;a href=&quot;http://www.spaceflightnow.com/news/n0603/21whirlpools/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.spaceflightnow.com/news/n0603/21whirlpools/&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="595" LastEditDate="2020-05-08T13:48:27.670" LastActivityDate="2020-05-08T13:48:27.670" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="4560" PostTypeId="2" ParentId="4541" CreationDate="2015-03-21T03:35:04.370" Score="6" Body="&lt;p&gt;My preferred way of doing this (I've been working in seismic data processing and analysis for over 20 years now) is: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Start with theoretical (or notional) source wavelet.&lt;/li&gt;&#xA;&lt;li&gt;Shape the source wavelet to zero phase (or minimum phase, depending on your&#xA;application).&lt;/li&gt;&#xA;&lt;li&gt;Design a cross-equalization filter that takes the input&#xA;from step 1 as the source and step 2 as the target. This can then be&#xA;globally applied to your data.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;There are other ways to do this (like with &lt;a href=&quot;http://en.wikipedia.org/wiki/Wiener_deconvolution&quot; rel=&quot;nofollow&quot;&gt;Wiener deconvolution&lt;/a&gt;) that make a statistical estimate of what the wavelet should look like, and this was considered acceptable in the industry for many years. However, such statistical processes are not acceptable for all applications, such as 4D (time lapse seismic) analyses, so I prefer processes that are deterministic rather than processes that rely on a stochastic assumption. &lt;/p&gt;&#xA;" OwnerUserId="2557" LastEditorUserId="28050" LastEditDate="2015-03-25T13:34:25.647" LastActivityDate="2015-03-25T13:34:25.647" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4561" PostTypeId="1" AcceptedAnswerId="7321" CreationDate="2015-03-21T05:16:55.520" Score="12" ViewCount="983" Body="&lt;p&gt;What causes the different colours of the salts pits in the Saloum Delta in Senegal?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/DYYKx.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-01-05T08:55:54.603" Title="What causes the different colours of the salt pits in the Saloum Delta in Senegal" Tags="|rivers|salinity|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4562" PostTypeId="1" CreationDate="2015-03-21T18:30:39.997" Score="11" ViewCount="1809" Body="&lt;p&gt;According to the &lt;a href=&quot;http://en.wikipedia.org/wiki/Opal&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia page about opals&lt;/a&gt;, this hydrated amorphous silica based gemstone is most commonly found in Australia, with according to the page, over 90% from Australia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/rcj1L.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Opal from Coober Pedy, South Australia (source: Wikipedia)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What geological conditions resulted in most opal deposits occurring in Australia?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-03-22T02:06:32.257" LastActivityDate="2015-03-22T02:06:32.257" Title="Why do most opal deposits occur in Australia?" Tags="|geochemistry|mineralogy|minerals|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4563" PostTypeId="2" ParentId="4562" CreationDate="2015-03-21T18:30:39.997" Score="11" Body="&lt;p&gt;A recent study published in the &lt;em&gt;Australian Journal of Earth Sciences&lt;/em&gt;, &lt;a href=&quot;http://www.tandfonline.com/doi/pdf/10.1080/08120099.2013.784219&quot; rel=&quot;noreferrer&quot;&gt;Opalisation of the Great Artesian Basin (central Australia): an Australian story with a Martian twist&lt;/a&gt; (Rey, 2013). The study makes the assertion that a unique set of geological conditions existed during the Cretaceous era that led to the relative abundance of opals in Central Australia. Rey proposes a 'redox model' of opal formation to account for the great relative abundance of the precious stone in Australia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An important aspect to note is that just about all opal deposits occur either in or on the periphery of the Great Artesian Basin, as can be seen in the map below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/e4JPz.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Image Source and brief information of opal mining centres: &lt;a href=&quot;http://www.nationalopal.com/opals/australian-opal-fields.html&quot; rel=&quot;noreferrer&quot;&gt;The National Opal Collection&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The conditions around the opal field part of the Artesian Basin during the Cretaceous, according to Rey (2013) were:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;From about 130 to 93 million years ago, The Great Artesian Basin was flooded by what is known as the Eromanga Sea, this was a cold, shallow, largely stagnant waterway that was poorly connected to the open ocean.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The Eromanga Sea served as a 'sink' for volcaniclastic sediments eroded from orogenic volcanic sources on the Pacific margin of Gondwana.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Rey describes how the iron- and organic- rich sediments contributed to an anoxic seafloor environment that became rich in pyrite, ferrous iron, feldspar and volcaniclasts, but virtually no carbonates. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the end of the Cretaceous and into the early Palaeogene (from about 93 to 60 million ears ago), the region experienced slow uplift, erosion and denudation, as well as subsequent sea regression; this, according to Rey, caused an acidic oxidation of the Eromanga Sea deposits as oxic fluids perculated through faults, some trapped by clay deposits - these are where the opal deposits have been found.  Further deposition in the Palaeocene and Eocene provided protection from further erosion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In summary, Rey notes 5 aspects unique to the geological history of the Great Artesian Basin that has resulted in the great relative abundance of opal:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Large scale organic matter-rich, iron-rich volcaniclastic sediments&lt;/li&gt;&#xA;&lt;li&gt;The depositional environment to be anoxic&lt;/li&gt;&#xA;&lt;li&gt;negligible carbonates&lt;/li&gt;&#xA;&lt;li&gt;sea regression driving oxidative weathering&lt;/li&gt;&#xA;&lt;li&gt;stable landscape to preserve opal from erosion and to prevent its transformation into quartz via burial&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The connection to Mars in the title is based on recent observations by &lt;a href=&quot;http://www.nasa.gov/mission_pages/MRO/news/mro-20081028.html&quot; rel=&quot;noreferrer&quot;&gt;NASA&lt;/a&gt; of opaline minerals found on the Martian surface, Rey suggests that there could be a link with the conditions with the dehydration of Eromanga Sea in the Cretaceous and processes that may have occurred on Mars.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastActivityDate="2015-03-21T18:30:39.997" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4564" PostTypeId="1" CreationDate="2015-03-22T08:44:23.513" Score="10" ViewCount="312" Body="&lt;p&gt;On Earth, weather is very much affected by the Earth's rotation around its axis and around the Sun. Even locations that are almost on the equator do have &lt;a href=&quot;https://weatherspark.com/averages/29126/Sao-Tome-Sao-Tome-Sao-Tome-and-Principe&quot; rel=&quot;noreferrer&quot;&gt;strong annual variations&lt;/a&gt; in precipitation and other characteristics. On the other hand, on a tidally-locked planet (TLP), there are no cycles. The star is still on one place on the sky. From the point of view of the global circulation models, which are most often used for studies of the climate of TLP, this is an ideal steady state.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: &lt;em&gt;What weather changes and cycles should one expect on tidally-locked planets, where no astronomical cycle acts as external forcing? Would the weather in a particular location change at all?&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="943" LastEditorDisplayName="user889" LastEditDate="2015-03-28T13:30:50.073" LastActivityDate="2015-03-29T00:22:56.403" Title="How would weather change on a tidally-locked terrestrial planet?" Tags="|meteorology|planetary-science|hypothetical|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4566" PostTypeId="2" ParentId="4503" CreationDate="2015-03-22T16:15:28.073" Score="2" Body="&lt;p&gt;Paleontologists do test hypotheses, and often the test is field work to collect fossils of ancient life as evidence of past environments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, if a geologist finds a sandstone it may not be clear whether that rock formed in a marine or desert environment. The geologist might search for fossil clams to disprove that the rock formed in a desert. (Because we know clams are animals that live in aquatic environments.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A paleontologist, with knowledge of clam biology, might need to be consulted to determine whether the fossil clam is a freshwater or marine specie of clam. The same specie might exist today, living in marine environments. This can provide information about other species, fossilized and found in the same rock formation, for which we do have not present day example - for example a specie of fish that is extinct today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have seen some good classroom lessons about paleontology that focus on how fossilized life provides information about ancient environments. Activities suitable for elementary students focus upon contrasting the environments which are likely to preserve fossils of familiar plants and animals: ferns, palm leaves, willow leaves, clams, fish etc.  The great result of paleontology is that there is abundant evidence for plants and animals, no longer living on the planet, that were very different but clearly related to present day life. Dinosaurs and trilobites are different than animals that live today, but also self-evidently animals. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To introduce Paleontology to third-grade students without pointing out that it provides some of the best evidence in support of the evolution of species is, at best a disservice, and at worse a crime against their education.      &lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorUserId="178" LastEditDate="2015-03-22T16:56:27.210" LastActivityDate="2015-03-22T16:56:27.210" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4567" PostTypeId="1" AcceptedAnswerId="4583" CreationDate="2015-03-22T19:41:35.157" Score="3" ViewCount="506" Body="&lt;p&gt;How can one determine the number of bytes in the SEGD Revision1 interblock gap?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The quantity is present on page 5 of the &lt;a href=&quot;http://www.google.com/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=1&amp;amp;ved=0CB8QFjAA&amp;amp;url=http%3A%2F%2Fwww.seg.org%2Fdocuments%2F10161%2F77915%2Fseg_d_rev1.doc&amp;amp;ei=kBgPVY_rN8vYggT1koLACw&amp;amp;usg=AFQjCNFw_v1mXQI7KvOLBIUTT6jof_GYMA&amp;amp;sig2=XamJ0jul-LnpoXrx1lLV7w&amp;amp;bvm=bv.88528373,d.eXY&amp;amp;cad=rja&quot; rel=&quot;nofollow&quot;&gt;standards document&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2696" LastActivityDate="2015-03-24T21:47:13.930" Title="How to determine the number of bytes in the SEGD Revision 1 interblock gap" Tags="|seismology|data-formats|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4568" PostTypeId="1" AcceptedAnswerId="8842" CreationDate="2015-03-22T22:38:41.667" Score="10" ViewCount="133" Body="&lt;p&gt;Salt Pans (such as in Badwater Basin of Death Valley, California) often show a tessellation pattern which forms presumably due to contraction of the deposited salt crust forming irregular cracks towards which the salt crust bends upwards and creates ridges. The cells of this tessellation have a characteristic size of 1-2 meters. I wonder whether a simple model exists which can explain the size of the cells, i.e. why they are 1-2m in size as opposed to 5cm or 10m.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If someone has researched this in the past, I would be interested in some references. Otherwise, some ideas or speculations are appreciated. Some related questions: would the cell size change with a different salt (Badwater Basin is covered predominantly by NaCl)? Does the composition of the underlying soil or rock matter? Does it rather depend on the diurnal temperature time-course characteristic of the place? &lt;/p&gt;&#xA;" OwnerUserId="2697" LastEditorUserId="2536" LastEditDate="2017-01-16T16:14:22.797" LastActivityDate="2017-05-16T18:51:07.273" Title="Cell Size of Salt Pan Tessellations" Tags="|precipitation|soil|desert|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4569" PostTypeId="1" CreationDate="2015-03-23T00:21:29.750" Score="7" ViewCount="218" Body="&lt;p&gt;I want to recreate the rock cycle using some item that can behave as a rock. The purpose of this is to get a point across to my students about how really there is a reason why the rock cycle is called rock cycle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of them find rocks dull and uninteresting, so I was thinking about proving the rock cycle some other way. In a couple of hours researching I came across some surprising ideas, such as crayons, chocolates, wax, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I wanted some feedback on how well you think I can get the point across of the rock cycle being a cycle. To them, thinking that something liquid, turn into solid, then gets destroyed, and mixed into something else, then melted again, is really hard to understand. Using something that does not take millions of years to form might be a better strategy I think. &lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="28050" LastEditDate="2015-10-29T15:55:04.333" LastActivityDate="2015-10-29T15:55:04.333" Title="Recreating the rock cycle" Tags="|geology|geochemistry|rocks|biogeochemistry|teaching|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="4570" PostTypeId="1" CreationDate="2015-03-23T07:24:46.343" Score="7" ViewCount="1486" Body="&lt;p&gt;With the increase of incidence angle, a portion of a P-wave converts into a S-wave, how does this behaviour occur?&lt;/p&gt;&#xA;" OwnerUserId="2698" LastEditorDisplayName="user889" LastEditDate="2015-03-23T09:35:00.600" LastActivityDate="2015-03-31T23:05:00.530" Title="Why does part of the P-wave convert into a S-wave with an increase of incidence angle?" Tags="|geophysics|seismology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4571" PostTypeId="2" ParentId="4439" CreationDate="2015-03-23T12:13:41.167" Score="3" Body="&lt;p&gt;Generally the relationship is the lower the air pressure the more intense the hurricane. For example during the same hurricane season as Katrina (2005) which also happened to be a record breaking season for the number of hurricanes recorded in the Atlantic basin, hurricane Wilma was recorded as being the most intense hurricane ever to form in the Atlantic. It reached a minimum air pressure of 882 millibar which was a record low. The corresponding maximum wind speed during this period of intensification was 185 mph. Hurricane Katrina was also a category 5 hurricane and reached a minimum air pressure of 902 millibar with maximum wind speeds at this pressure of 175 mph. Katrina of course striking where it did caused far more destruction even though it was the less intense hurricane of the two:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Hurricane_Wilma&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/Hurricane_Wilma&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Hurricane_Katrina&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/Hurricane_Katrina&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2693" LastActivityDate="2015-03-23T12:13:41.167" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4572" PostTypeId="1" AcceptedAnswerId="4573" CreationDate="2015-03-23T16:57:02.940" Score="7" ViewCount="143" Body="&lt;p&gt;In a cyclone, the pressure gradient force (PGF) and the Coriolis force sustain the spinning motion and causes the direction of spin (counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere). Are there vortices in the atmosphere which are sustained only by the pressure gradient force?&lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorUserId="192" LastEditDate="2015-03-23T19:45:15.347" LastActivityDate="2015-03-23T19:45:15.347" Title="Vortices in the Atmosphere Sustained only by PGF" Tags="|meteorology|vorticity|cyclone|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4573" PostTypeId="2" ParentId="4572" CreationDate="2015-03-23T19:43:27.743" Score="9" Body="&lt;p&gt;Tornadoes, land/waterspouts and supercell thunderstorm mesocyclones are examples of vortices where Coriolis is unimportant.  Tornadoes are in cyclostrophic balance.  Land and waterspouts (as well as non-supercell tornadoes) arise from horizontal convergence of vertical vorticity.  The supercell mesocyclone spin originates as horizontal vorticity that is tilted and stretched into vertical vorticity.  These vorticies can spin in either direction in either hemisphere.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-03-23T19:43:27.743" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4574" PostTypeId="1" AcceptedAnswerId="4596" CreationDate="2015-03-23T22:09:15.493" Score="17" ViewCount="2498" Body="&lt;p&gt;The atmosphere &lt;a href=&quot;http://teachertech.rice.edu/Participants/louviere/comp.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;is 21% oxygen&lt;/a&gt;. I assume that there must be an equilibrium between processes that produce oxygen (e.g. &lt;a href=&quot;http://www.rsc.org/Education/Teachers/Resources/cfb/Photosynthesis.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;photosynthesis&lt;/a&gt;) and those that consume oxygen (e.g. &lt;a href=&quot;http://www.rsc.org/Education/Teachers/Resources/cfb/Respiration.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;aerobic respiration&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Moreover, there should be a self-regulatory negative feedback which restores the equilibrium if the system is driven away from it.  If the amount of oxygen were increased, something that would subsequently cause it to decrease over time, and if the amount of oxygen were decreased, something to cause it to be replenished.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;What processes are responsible for this negative feedback?&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="943" LastEditorDisplayName="user12525" LastEditDate="2019-04-28T13:27:02.110" LastActivityDate="2019-04-28T13:27:02.110" Title="How is the equilibrium of 21% oxygen in Earth's atmosphere established?" Tags="|atmosphere|atmospheric-chemistry|biogeochemistry|oxygen|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4575" PostTypeId="1" AcceptedAnswerId="4578" CreationDate="2015-03-24T04:23:40.640" Score="7" ViewCount="490" Body="&lt;p&gt;According to &lt;a href=&quot;http://www.bbc.com/earth/story/20150323-how-long-will-life-on-earth-last&quot; rel=&quot;noreferrer&quot;&gt;How Long Will Life Last On Earth&lt;/a&gt;, 250 million years ago Siberia underwent a large a prolonged period of volcanic activity. It has been speculated that large salt deposits that existed in Siberia, and still do, were baked by the volcanic activity and large amounts of ozone destroying chemicals were released into the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What ozone depleting chemicals can salt produce?&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="543" LastEditDate="2015-03-25T23:13:23.963" LastActivityDate="2015-03-25T23:13:23.963" Title="What ozone depleting chemicals can salt produce?" Tags="|atmosphere|volcanology|geochemistry|volcanoes|ozone|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4576" PostTypeId="1" AcceptedAnswerId="4588" CreationDate="2015-03-24T04:37:22.063" Score="3" ViewCount="131" Body="&lt;p&gt;A second question inspired from &lt;a href=&quot;http://www.bbc.com/earth/story/20150323-how-long-will-life-on-earth-last&quot; rel=&quot;nofollow&quot;&gt;How Long Will Life Last On Earth&lt;/a&gt;, The Manicouagan crater in Canada is one of the largest impact crater on Earth.  It was created 215 million years ago, but its formation did not trigger a mass extinction event. It is claimed that this is because the impact occurred in crystalline rock. It is also claimed that had the event occurred in sedimentary rock clouds of climate-changing gases could have been released into the atmosphere, which could have triggered a mass extinction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What different gases could be produced by a significant asteroid impact in crystalline and sedimentary rocks?&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorDisplayName="user889" LastEditDate="2015-03-25T19:30:13.367" LastActivityDate="2015-03-25T19:30:13.367" Title="The differences in gases produced by asteroids impacting crystalline and sedimentary rocks" Tags="|atmosphere|rocks|gas|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4577" PostTypeId="1" AcceptedAnswerId="4579" CreationDate="2015-03-24T05:55:44.937" Score="21" ViewCount="23102" Body="&lt;p&gt;I am an undergraduate student but I am a tutor at a High School, and one student asked me. Attempting to explain the rock cycle &quot;if one rock turns into the other then which came first&quot; my gut is telling me probably igneous (given Earth geologic past.) Resources online have different opinions. Am I right in my assumption?&lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="725" LastEditDate="2015-03-24T08:05:00.080" LastActivityDate="2022-01-03T12:15:58.327" Title="What was the first rock in the rock cycle?" Tags="|geology|geochemistry|earth-history|rocks|" AnswerCount="6" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4578" PostTypeId="2" ParentId="4575" CreationDate="2015-03-24T06:35:55.873" Score="3" Body="&lt;p&gt;A study presented in the Science Daily article (based on a &lt;em&gt;Science&lt;/em&gt; article), &lt;a href=&quot;http://www.sciencedaily.com/releases/2001/01/010119080544.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Study: Sea Salt Seasons Chemical Brew That Destroys Arctic Ozone&lt;/a&gt; (Purdue University, 2001) could serve as an analogue to salt induced ozone depletion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sea salt, in particular, compounds formed from the constituent chlorine, bromine (and fluorine) found in most salts have been identified as ozone depletors - researchers have found that the sea salt in the Arctic containing these ions cause a seasonal thinning in the Arctic.  With a large concentration of salt in the strata, as found in the region of the Siberian Traps, it is not inconceivable to assume that large quantities of chlorine and bromine were released in the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quantitatively, according to the article &lt;a href=&quot;http://home.dtm.ciw.edu/users/ltelkins/pdfs_of_papers/Black%20EPSL%20melt%20inclusions%202012.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Magnitude and consequences of volatile release from the Siberian Traps&lt;/a&gt; (Black et al. 2012), the actual amount released was in the order of approximately ~3400–8700 Gt chlorine, of which a good proportion was, according to the article, assimilated into the magma from melting of the evaporite, salt and sedimentary rocks.  Also postulated by &lt;a href=&quot;http://www.pnas.org/content/101/35/12952.long&quot; rel=&quot;nofollow noreferrer&quot;&gt;Environmental mutagenesis during the end-Permian ecological crisis&lt;/a&gt; (Visscher et al. 2004) was that the size of the Siberian volcanics caused the assimilation of volumnous organics and halogen based deposits (including salts).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These hypotheses are supported by experiments reported in the article &lt;a href=&quot;http://folk.uio.no/hensven/Svensen_EnviChem09_halocarbons.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Contact metamorphism, halocarbons, and environmental&#xA;crises of the past&lt;/a&gt; (Svenson et al. 2009), where rock salt from Siberia was heated to 275C released &lt;a href=&quot;http://www.environment.gov.au/protection/ozone/ozone-depleting-substances&quot; rel=&quot;nofollow noreferrer&quot;&gt;ozone depleting halocarbons&lt;/a&gt; such as methyl chloride (CH&lt;sub&gt;3&lt;/sub&gt;Cl) and methyl bromide (CH&lt;sub&gt;3&lt;/sub&gt;Br).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, considering the most common salt is sodium chloride (NaCl), once dissolved, the chloride ion (Cl&lt;sup&gt;-&lt;/sup&gt;) is very reactive, and forms several ozone depleting compounds (such as the halocarbon examples above), and chlorine itself can react to 'tear apart' ozone itself, as shown in the diagram below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/stZVH.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Image Source: &lt;a href=&quot;http://www.esrl.noaa.gov/gsd/outreach/education/samii/SAMII_Activity3.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The example used in the image above are manmade CFC's (chlorofluorocarbons), however, it can be applied to any halocarbon or for chlorine itself from step 3 onwards.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In conclusion, any halogen (particularly F, Cl, Br) based salt are potential ozone depletors, due to the reactivity of the halogen ions.  Especially Cl due to how common NaCl salt is, the Cl (and other halogens) can react with other chemicals that may be present also providing ozone depleting chemicals.  So, given the amount of salt that the Siberian Traps that would have heated up, the chances of a fairly large effect on the ozone layer at the time are pretty good.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-03-24T09:21:28.163" LastActivityDate="2015-03-24T09:21:28.163" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4579" PostTypeId="2" ParentId="4577" CreationDate="2015-03-24T08:04:10.773" Score="22" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;which came first&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That's actually a very hard question. The most simple answer would indeed be igneous. Here's why:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Sedimentary rocks (in the sense of rock cycle) comes from pre-existing igneous or metamorphic rocks, so you need to have had them first.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Metamorphic rocks, by definition, are rocks that form from other kinds of rocks (be it igneous or metamorphic).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Igneous rocks form by melting of other rocks. Now here is the catch - what do you consider &quot;other rocks&quot;? The first igneous rocks on Earth (or to be exact - the proto-Earth) likely formed by impact melting of various small planetary bodies hitting each other and coalescing to form the Earth. These planetesimals formed by condensation of gas from the solar nebula, before Earth even existed, and before the rock cycle began.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;So yes, igneous rocks were here first. The rocks (or material, if you wish) that existed before the igneous rocks do not fit into the traditional igneous/sedimentary/metamorphic definitions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, note that the rules of the rock cycle aren't written in stone (pun intended). What about evaporites? Rocks such as halite or gypsum beds form on the surface on the Earth, and their constituents aren't derived directly from either igneous or metamorphic rocks. What about sandstones that form by weathering of former sandstones? What about igneous rocks that form by partial melting of metamorphic rocks, and then melt again without ever reaching the surface to become sedimentary rocks? And my favourite one: pyroclastic rocks. Are they sedimentary or igneous? One textbook quips that they're igneous going up, and sedimentary going down.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-03-24T08:04:10.773" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4580" PostTypeId="2" ParentId="4577" CreationDate="2015-03-24T08:34:27.437" Score="7" Body="&lt;p&gt;I suppose it also depends on how far back we go.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth is a rocky planet formed by the accretion/agglomeration of cosmic dust and ice. One might argue that the first rock of Earth was an agglomeration, and once a critical mass had been reached, the agglomerated core heated and began to melt creating igneous rock, assisted by the heat of bombardment from more cosmic rocks and of radioactive decay.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2015-03-25T00:40:23.270" LastActivityDate="2015-03-25T00:40:23.270" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4581" PostTypeId="2" ParentId="4553" CreationDate="2015-03-24T10:02:33.813" Score="5" Body="&lt;p&gt;For long-term sea level data, some of the &lt;a href=&quot;http://www.psmsl.org/&quot;&gt;PSMSL&lt;/a&gt; (Permenant Service for Mean Sea Level) datasets may be of use. These only cover discrete points, mostly tide gauges on coasts, but do so for the long term, giving monthly and annual means.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2015-03-24T10:02:33.813" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4583" PostTypeId="2" ParentId="4567" CreationDate="2015-03-24T21:47:13.930" Score="3" Body="&lt;p&gt;There are no bytes in an IBG. SEGDrev1 is a tape format, and the schematic you are referencing in the standards document is a map of how the data is physically stored on a tape. Tape gaps are actual physical spaces on the tape between blocks of data. An IBG is, quite literally, a gap between blocks of actual data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are reading a tape, you should be able to advance the tape to the next block as needed. If you are working with a SEGD file that has been copied to a hard disk, then gaps are nonexistent and you can pretend they are not there. &lt;/p&gt;&#xA;" OwnerUserId="2557" LastActivityDate="2015-03-24T21:47:13.930" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4584" PostTypeId="1" CreationDate="2015-03-25T03:18:14.353" Score="14" ViewCount="2479" Body="&lt;p&gt;I am doing a paper about coastal processes and I was told that I should include a sediment transport modeling to further examine my geophysical findings. I was reading in the net and found that Delft3D Suite seems to be the best option, however I have no funding to pay for a license because it is all science.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone have software suggestions to model coarse sediment transport?&lt;/p&gt;&#xA;" OwnerUserId="2713" LastEditorUserId="725" LastEditDate="2016-08-09T09:11:36.597" LastActivityDate="2016-08-09T09:11:36.597" Title="Software for sediment transport modeling" Tags="|models|sedimentology|waves|wave-modeling|software|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4585" PostTypeId="2" ParentId="4577" CreationDate="2015-03-25T03:18:47.760" Score="15" Body="&lt;p&gt;The Earth existed long before there were crustal rocks or a &quot;rock cycle.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The idea of the &quot;rock cycle&quot; has prerequisites to even be meaningful. These include:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The existence of a crust (both a continental and oceanic crust actually.)&lt;/li&gt;&#xA;&lt;li&gt;Plate tectonics&lt;/li&gt;&#xA;&lt;li&gt;The existence of an atmosphere and ocean.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Without all of these, the concept of the rock cycle (as introduced in textbooks) really is not applicable. (You might suppose there were other 'rock cycles' in the very distant past but that is not what is discussed in undergraduate textbooks.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth is older than (1) (2) or (3) - so when these preconditions were not in place there was no rock cycle.  The three preconditions also did not &quot;turn on&quot; at exactly the same time. It took a long time for the Earth's crust to form (&lt;a href=&quot;http://serc.carleton.edu/NAGTWorkshops/earlyearth/questions/crust.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;When and how did continental crust form?&lt;/a&gt;). Oceans and lakes appeared later (&lt;a href=&quot;http://serc.carleton.edu/NAGTWorkshops/earlyearth/questions/formation_oceans.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;When did oceans form on Earth?&lt;/a&gt;). Plate tectonics may have began early (&lt;a href=&quot;http://serc.carleton.edu/NAGTWorkshops/earlyearth/questions/tectonics.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;When did plate tectonics begin?&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The point is that the planetary conditions necessary for the rock cycle we see evidence for in the geology of the last billion years or so evolved over much time. Earth was very different in the distant past.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the reason why there are no scientists working on the question: &quot;What was the first rock in the rock cycle?&quot;  Scientists would like to answer big questions, such as:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;When and how did the crust form?&lt;/li&gt;&#xA;&lt;li&gt;When and how did the oceans and atmosphere form?&lt;/li&gt;&#xA;&lt;li&gt;When and how did plate tectonics begin?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="178" LastEditorUserId="18081" LastEditDate="2019-12-03T20:15:06.797" LastActivityDate="2019-12-03T20:15:06.797" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="4586" PostTypeId="1" AcceptedAnswerId="4978" CreationDate="2015-03-25T03:54:22.860" Score="9" ViewCount="376" Body="&lt;p&gt;I would like to calculate the bankfull flow for a certain point on a river.  The recurrence interval of bankfull flow varies for different rivers, but is typically always found to be between 1 and 2 years.    Let's imagine I decide to set the recurrence interval at 1.67 years, which gives me an exceedance probability of approximately 60% ($\rm Pr(X\geq0.60) = Pr(X\leq0.40)$).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Supposing I have a stream gage at the point I am interested in estimating bankfull flow for, and I recorded hourly discharge values for 20 years, which set of values should I use to calculate the recurrence interval? Should I determine the value associated with this exceedance probability using all hourly flows, the daily mean flows, the annual high flows (what the USGS calls instantaneous peak flows), or some other subset of values?&lt;/p&gt;&#xA;" OwnerUserId="2714" LastEditorUserId="725" LastEditDate="2015-06-12T22:44:19.563" LastActivityDate="2015-06-12T22:44:19.563" Title="When calculating flood recurrence intervals, do you use annual instantaneous peak flows?" Tags="|rivers|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4587" PostTypeId="2" ParentId="4584" CreationDate="2015-03-25T07:22:28.680" Score="7" Body="&lt;p&gt;Large parts of Delft3D - including, I think, the sediment transport module - are available in an open source form. The GUI is not currently open source, but (a) Deltares have been offering licences for this for free for academic use; (b) if they are no longer doing this, it is entirely possible to use the software without the GUI. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;FVCOM also has a sediment transport module, and is available free for academic use.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This isn't what you asked, but I will note that if you don't have experience with hydrodynamic modelling, or access to somebody who does, then the use of these models may have a steep and time-consuming learning curve. &lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2015-03-25T07:22:28.680" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4588" PostTypeId="2" ParentId="4576" CreationDate="2015-03-25T10:42:12.660" Score="2" Body="&lt;p&gt;A New Scientist article (with a somewhat amusing title) &lt;a href=&quot;https://henriksvensen.files.wordpress.com/2013/12/new_scientist.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fracking Hell&lt;/a&gt; investigates this exact question in some detail.  The difference is made by an analogue to the process of &lt;a href=&quot;http://en.wikipedia.org/wiki/Hydraulic_fracturing&quot; rel=&quot;nofollow noreferrer&quot;&gt;fracking&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Instead of the water use in human-engineered process of fracking breaking the underlying rocks up to release the methane for commercial purposes. The considerably larger impact of an asteroid does the same thing in a massively uncontrolled manner - in sedimentary rocks, it pulverises the sedimentary rock, releasing the gases that were trapped in it, such as sulphur from &lt;a href=&quot;http://geology.gsapubs.org/content/21/3/211.abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;evaporites in the vicinity of the Chixculub impact&lt;/a&gt;; other gases can include hydrocarbons, halocarbons (salt + hydrocarbons), chlorine to name a few.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The amount of gases released from within the sedimentary rocks were enough to cause mass extinctions (in an essentially extraterrestrial version of what is believed to have occurred during the &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4575/what-ozone-depleting-chemicals-can-salt-produce&quot;&gt;Siberian Traps&lt;/a&gt; event).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In crystalline rocks (such as igneous and metamorphic rocks), according to the article, the rocks are far more stable and do not release such amounts of climate changing gases than sedimentary strata in an impact event.  Although these rocks can contain gas bubbles etc, they have been found to relatively 'inert; in terms of gaseous release compared to sedimentary rocks, such as the 100km diameter &lt;a href=&quot;http://www.lpi.usra.edu/publications/slidesets/geology/sgeo/slide_18.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Manicouagan crater&lt;/a&gt; in Canada, an event not associated with a mass extinction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Essentially, the impacts can be devastating for either scenario, but the impact itself is not the only cause of mass extinctions, it appears that a large factor of the mass extinctions is due to the climatic change that results from the released gases uncontrollably 'fracked' out of the sedimentary rocks. Of course, if an impact is large enough, it could pulverise several layer of rock unlocking deep pockets of gases.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-03-25T11:23:43.333" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4589" PostTypeId="1" AcceptedAnswerId="4590" CreationDate="2015-03-25T12:10:40.480" Score="11" ViewCount="7979" Body="&lt;p&gt;Antarctica receives heat from the Sun every day, so how does it stay frozen?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have some thoughts about the answer but I'm unsure of whether it is correct; I hope people here can clarify. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My idea: the heat that Antarctica receives from the Sun is always 'travelling' from one spot to another, but the heat does not stay in a spot long enough to melt the ice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please correct me if I'm wrong, thanks.&lt;/p&gt;&#xA;" OwnerUserId="2721" OwnerDisplayName="wtoh" LastEditorUserId="2470" LastEditDate="2021-07-06T06:58:13.323" LastActivityDate="2021-07-06T06:58:13.323" Title="How does Antarctica stay frozen?" Tags="|climate|thermodynamics|ice|antarctica|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4590" PostTypeId="2" ParentId="4589" CreationDate="2015-03-25T12:38:48.967" Score="12" Body="&lt;p&gt;It doesn't stay frozen.  Ice evaporates (or sublimates is the correct term) under direct sunlight, but that's at a molecular level, it doesn't melt, it goes from solid to gas under sunlight and in the cold, some of this newly formed water vapor goes back being to ice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In an absolutely dry climate, well below freezing, ice would slowly sublimate and disappear.  In a warm dry climate, ice would melt (much faster), then it would evaporate.   The sun does sublimate ice off the antarctic ice sheet every day, but quite a bit less than is added by snow and condensation from moisture due to temperature change and brought over by wind.   The antarctic ice sheet is also, always moving.   Mostly Antarctica loses ice by pushing it into the ocean - over long periods of time and it gains ice by (see above) snow and condensation.   The ice has been on Antarctica for over 30 million years, but as far as I know, the oldest ice core we've found there is about 1.5 million years old.    Everything moves.&lt;/p&gt;&#xA;" OwnerUserId="2717" OwnerDisplayName="userLTK" LastActivityDate="2015-03-25T12:38:48.967" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4591" PostTypeId="1" AcceptedAnswerId="4641" CreationDate="2015-03-25T13:22:20.387" Score="8" ViewCount="310" Body="&lt;p&gt;In 2006 it was reported that the &lt;a href=&quot;http://phys.org/news68455520.html&quot;&gt;Largest Ever Killer Crater&lt;/a&gt; was found under ice in Antarctica. Gravity measurements taken by NASA's GRACE satellites indicate the crater is 250 million years old.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The size and location of the crater, apparently 480 km across, located in the Wilkes Land region of Eastern Antarctica, south of Australia have lead to suggestion the crater could have initiated the break up of Gondwanaland by creating the tectonic rift that pushed Australia northward.  The rift cuts directly through the crater, so the impact may have helped the rift to form. Australia split from the ancient Gondwana super continent about 100 million years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has the existence of the crater been verified and did it lead to the break up of Gondwanaland and Australia separating from Antarctica?&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-04-02T14:03:27.453" Title="Did a crater cause the break up of Gondwanaland &amp; separate Australia from Antarctica" Tags="|tectonics|continental-rifting|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4592" PostTypeId="1" CreationDate="2015-03-25T13:53:49.923" Score="7" ViewCount="130" Body="&lt;p&gt;In the paper &lt;a href=&quot;https://www.slb.com/~/media/Files/resources/oilfield_review/ors09/win09/02_high_impact_reservoirs.pdf&quot; rel=&quot;noreferrer&quot;&gt;High Impact Reservoirs&lt;/a&gt;, the authors claim that impact craters have lead to both the creation and destruction of petroleum source rocks, reservoirs and traps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recently it was &lt;a href=&quot;http://www.sbs.com.au/news/article/2013/02/15/worlds-third-largest-asteroid-impact-zone-found-sa&quot; rel=&quot;noreferrer&quot;&gt;announced&lt;/a&gt; that a large impact crater may have been discovered in the East Warburton region of South Australia. The announcement was base on &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0040195113000188&quot; rel=&quot;noreferrer&quot;&gt;new research&lt;/a&gt;. If this is true, and allied with the finding presented in the paper on High Impact Reservoirs, could the recently announced impact crater in South Australia have lead to the formation of the &lt;a href=&quot;http://www.pir.sa.gov.au/__data/assets/pdf_file/0014/111056/203838_004.pdf&quot; rel=&quot;noreferrer&quot;&gt;Moomba gas fields&lt;/a&gt; in the Cooper and Eromanga basins which are within the East Warburton Basin region?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/cZMn5.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-11-22T10:03:22.370" Title="Did an impact crater cause the formation of the gas fields in north eastern South Australia" Tags="|geology|earth-history|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4593" PostTypeId="2" ParentId="4584" CreationDate="2015-03-25T14:06:05.060" Score="10" Body="&lt;p&gt;I think the best option for sediment transport modeling is the &lt;a href=&quot;http://woodshole.er.usgs.gov/project-pages/sediment-transport/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Community Sediment Transport Modeling System&lt;/a&gt; (&lt;a href=&quot;http://www.myroms.org/cstms/wiki/index.php/CSTMS:_Community_Sediment_Transport_Modeling_System&quot; rel=&quot;nofollow noreferrer&quot;&gt;CSTMS&lt;/a&gt;) package that was developed for ROMS. CSTMS was created by a group of sediment transport modelers lead by the USGS. One of the many benefits is that it is open-source and, thus, free. The model was designed for realistic simulations of processes causing sediment transport in the coastal ocean (estuaries, nearshore regions, and the continental shelf). Details on the package and its implementation are found in &lt;a href=&quot;http://dx.doi.org/10.1016/j.cageo.2008.02.012&quot; rel=&quot;nofollow noreferrer&quot;&gt;Warner et al (2008)&lt;/a&gt;. The people from FVCOM implemented this package.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/gRg6i.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most up-to-date version of the sediment transport module is part of the Coupled Ocean – Atmosphere – Wave – Sediment Transport (&lt;a href=&quot;http://woodshole.er.usgs.gov/operations/modeling/COAWST/&quot; rel=&quot;nofollow noreferrer&quot;&gt;COAWST&lt;/a&gt;) modeling system. A good description of the model and its capabilities is given in &lt;a href=&quot;http://dx.doi.org/10.1016/j.ocemod.2010.07.010&quot; rel=&quot;nofollow noreferrer&quot;&gt;Warner et al. (2010).&lt;/a&gt; The code can be downloaded from &lt;a href=&quot;https://coawstmodel-trac.sourcerepo.com/coawstmodel_COAWST/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The current version of CSTMS can model both cohesive (mud) and non-cohesive sediment (sand) sediments, bedload transport and sediment deposition and erosion caused by waves and currents.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-03-25T14:06:05.060" CommentCount="13" ContentLicense="CC BY-SA 3.0" />
  <row Id="4594" PostTypeId="1" AcceptedAnswerId="7232" CreationDate="2015-03-25T14:10:41.363" Score="9" ViewCount="310" Body="&lt;p&gt;As a supplementary question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4592/did-an-impact-crater-cause-the-formation-of-the-gas-fields-in-north-eastern-sout&quot;&gt;Did an impact crater cause the formation of the gas fields in north eastern South Australia&lt;/a&gt; . South Australia is a well documented uranium province. Could an impact crater, as announced in &lt;a href=&quot;http://phys.org/news/2013-02-world-largest-asteroid-impact-zone.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;early 2015&lt;/a&gt; have created conditions that would have allowed South Australia to be the uranium province that it is?&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-02-11T17:54:28.750" Title="Did an impact crater influence the formation of uranium deposits in South Australia?" Tags="|geology|geochemistry|earth-history|uranium|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4595" PostTypeId="1" AcceptedAnswerId="4946" CreationDate="2015-03-25T14:32:12.783" Score="13" ViewCount="557" Body="&lt;p&gt;A new study by &lt;a href=&quot;http://dx.doi.org/10.1073/pnas.1423252112&quot;&gt;Batygyin and Laughlin&lt;/a&gt; suggest that a Jupiter migration toward the inner region of the Solar System during the early stages of system formation cleared the habitable region (Goldilocks zone) around the Sun from early planets that too large and with atmospheres too dense to support life. As they put it:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Jupiter migrates inward from a &gt; 5 astronomical units (AU) to a ≈ 1.5 AU before reversing direction, can explain the low overall mass of the Solar System’s terrestrial planets.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They propose this scenario to explain the differences between the Solar System and other planetary systems in which large planets are found in the proximity of the starts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Among the many questions I have: How is it physically possible for such a migration to occur? Is there a way to verify the migration hypothesis with observations? How different would have been the hypothetical planets in the area currently occupied by Earth? If such a migration toward the Sun started, what prevented Jupiter from continuing inward and collapsing with the Sun? Is it possible for such a migration to occur again?&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-06-03T20:55:35.367" Title="Did Jupiter really make Earth (in)habitable?" Tags="|earth-history|planetary-science|planetary-formation|solar-terrestrial-physics|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4596" PostTypeId="2" ParentId="4574" CreationDate="2015-03-26T09:25:04.420" Score="9" Body="&lt;p&gt;I'm not sure I can give a good technical answer. I don't think the amount of oxygen in the Earth's atmosphere is due to equilibrium but more of a consequence of the formation of the solar system, Earth chemistry and biology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you look at the formation, for inner planets, much of the gas and ices were blown off due to their inner orbits and the planets being too hit by very active Coronal mass ejections in the early solar system. There are 3 likely types of close to the sun planets:   1) small rocky planets (Earth, Mercury, Venus, Mars), 2) hot jupiters, which are large enough to trap hydrogen even though they're close to the sun and hot and 3) super-earths, which have enough gravity to trap hydrogen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An abundance of hydrogen in a planetary atmosphere would likely make oxygen formation impossible.  The Oxygen would bind with the hydrogen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth didn't have the gravity to trap much hydrogen and some of the early atmosphere would have been blown off by large meteor strikes and by coronal mass ejections, which were much more common when the sun was young.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A clue to the Earth's atmosphere's formation is the formation of the oceans, because oceans would be impossible without an atmosphere.  The oceans formed 3.8 billion years ago, so we had to have an atmosphere, at least for about 3.8 billion years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://people.chem.duke.edu/~jds/cruise_chem/oceans/ocean1.html&quot;&gt;http://people.chem.duke.edu/~jds/cruise_chem/oceans/ocean1.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The young Earth's atmosphere was mostly methane (CH&lt;sub&gt;4&lt;/sub&gt;), ammonia (NH&lt;sub&gt;3&lt;/sub&gt;), water vapor (H&lt;sub&gt;2&lt;/sub&gt;O), and carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) as per the link above, as soon as the Earth was cool enough, the water vapour turned into liquid water (rain) and the oceans began to form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fast forward to the Great Oxygenation event when cyanobacteria, pulled CO&lt;sub&gt;2&lt;/sub&gt; from the air and release O&lt;sub&gt;2&lt;/sub&gt;.  Early on, the O&lt;sub&gt;2&lt;/sub&gt; binded with iron in the ocean and some of it likely reacts with CH&lt;sub&gt;4&lt;/sub&gt; and NH&lt;sub&gt;3&lt;/sub&gt; in the atmosphere when there is lightning. Over time, CO&lt;sub&gt;2&lt;/sub&gt; was pulled from the air, replaced by O&lt;sub&gt;2&lt;/sub&gt; and O&lt;sub&gt;2&lt;/sub&gt; reacted with CH&lt;sub&gt;4&lt;/sub&gt; and NH&lt;sub&gt;3&lt;/sub&gt;, producing more CO&lt;sub&gt;2&lt;/sub&gt;, H&lt;sub&gt;2&lt;/sub&gt;0, and N&lt;sub&gt;2&lt;/sub&gt; - the common elements we have today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oxygen levels in planets with cyanobacteria, likely depends on how much iron is dissolved in the oceans and how much hydrogen is in the atmosphere.  If there's not enough CO&lt;sub&gt;2&lt;/sub&gt; to produce enough O&lt;sub&gt;2&lt;/sub&gt; to saturate the iron and hydrogen, the planet probably never gets much O&lt;sub&gt;2&lt;/sub&gt; in it's atmosphere - so it's all about the ratio of early elements.    Super-earths might never get oxygen atmospheres - too much hydrogen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You also get factors like the development of lignin (got that from Neil deGrass' Cosmos) - &lt;a href=&quot;http://evolution.about.com/od/Cosmos/fl/Cosmos-A-Spacetime-Odyssey-Recap-Episode-109.htm&quot;&gt;http://evolution.about.com/od/Cosmos/fl/Cosmos-A-Spacetime-Odyssey-Recap-Episode-109.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lignin made trees possible, but nothing could eat trees, so trees captured more and more carbon, so CO&lt;sub&gt;2&lt;/sub&gt; levels fell and O&lt;sub&gt;2&lt;/sub&gt; levels rose.   About 100 million years later, termites evolved and the digestion of trees released much of this captured CO&lt;sub&gt;2&lt;/sub&gt; became possible and Oxygen and CO&lt;sub&gt;2&lt;/sub&gt; leveled out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shellfish, to make their shells, take more O&lt;sub&gt;2&lt;/sub&gt; out of the air than CO&lt;sub&gt;2&lt;/sub&gt; (calcium carbonate has lots of oxygen in it).   That's a slow process, but over time it takes some O&lt;sub&gt;2&lt;/sub&gt; out of the air, so over tens of millions of years, parts of the atmosphere are effectively sequestered and trapped in the Earths crust, but over time, some of this is also returned to the atmosphere with volcanic activity - so the type of life forms present is also a factor and the extent of tectonic activity is a factor as is, as is the presence of a Jupiter and how many comets are likely to hit the planet and the size of the planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's more chance, the solar system and planetary factors that lead to a planet's atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer your question:  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;So if we increase the amount of oxygen, it will decrease over time and&#xA;  if we decrease it, it will be replenished.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Tough call regarding oxygen.   CO&lt;sub&gt;2&lt;/sub&gt; is easier.    Because there's a relatively small percentage of CO&lt;sub&gt;2&lt;/sub&gt; in the air, more CO&lt;sub&gt;2&lt;/sub&gt; will lead to some of it dissolving in the ocean as carbolic acid, though the warming of the ocean might also slow the oceanic absorption of CO&lt;sub&gt;2&lt;/sub&gt;.     Because there's so much more Oxygen in the Earth, 21% vs 0.04% of CO&lt;sub&gt;2&lt;/sub&gt;, a measurable increase, say 21% to 22%, you'd probably see a slight increase in dissolved O&lt;sub&gt;2&lt;/sub&gt; in the ocean, but beyond that, I don't think you'd see that extra oxygen go away any time soon.  My guess is, if such an increase was done, it would last a long time, hundreds of thousands of years if not millions, because oxygen sequestering is pretty slow.     Insects would get slightly bigger pretty quick.   That might be the most noticeable effect.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you significantly increase O&lt;sub&gt;2&lt;/sub&gt; levels, say from 21% to 30%, things would become noticeably more flammable and over time, our lungs would probably get smaller and there would be other effects, probably.    But I don't believe there's any sort of equilibrium that would fairly quickly bring it back to 21%.     &lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2015-03-26T14:45:37.320" LastActivityDate="2015-03-26T14:45:37.320" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4597" PostTypeId="1" CreationDate="2015-03-26T10:19:32.930" Score="9" ViewCount="2309" Body="&lt;p&gt;According to the &lt;a href=&quot;http://www.world-nuclear.org/info/Country-Profiles/Countries-A-F/Australia/&quot; rel=&quot;nofollow noreferrer&quot;&gt;World Nuclear Energy&lt;/a&gt; page about Australia's uranium deposits, the continent's&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;known uranium resources are the world's largest – 31% of the world total. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Of which&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In 2013 Australia produced 7488 tonnes of U&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;8&lt;/sub&gt;. It is the&#xA;  world's third-ranking producer, behind Kazakhstan and Canada. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The deposits are found across the Australian continent, within different geological regions of different ages (e.g. most of the deposits in the eastern part of the continent are considerably younger than those in the west).  The main known deposits are shown in the map below, by &lt;a href=&quot;http://www.ga.gov.au/data-pubs/data-and-publications-search/publications/aimr/uranium&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geoscience Australia&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/B7H6n.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Why does Australia have extensive uranium ore deposits?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Related to this question is the recent question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4594/did-an-impact-crater-influence-the-formation-of-uranium-deposits-in-south-austra&quot;&gt;Did an impact crater influence the formation of uranium deposits in South Australia&lt;/a&gt;, and related questions and answers, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2294/why-is-there-uranium-in-earths-crust&quot;&gt;Why is there Uranium in Earth's Crust?&lt;/a&gt; and &lt;a href=&quot;https://earthscience.stackexchange.com/questions/102/how-much-uranium-is-there-in-the-earths-crust&quot;&gt;How much Uranium is there in the Earth's Crust?&lt;/a&gt;&lt;/em&gt; - this question is specific to the relatively high abundance of uranium occurring in the Australian landmass.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-05-07T07:48:59.980" Title="Why does Australia have extensive uranium ore deposits?" Tags="|geochemistry|economic-geology|uranium|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4598" PostTypeId="2" ParentId="2176" CreationDate="2015-03-27T00:12:52.320" Score="8" Body="&lt;p&gt;Sahara greening is generally driven by the strength of the North African Monsoon, which follows the earth's orbital cycles pretty neatly.   (Piquet's answer covers this).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/North_African_climate_cycles&quot; rel=&quot;noreferrer&quot;&gt;http://en.wikipedia.org/wiki/North_African_climate_cycles&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer to how much man made climate change will affect the North African Monsoon extent isn't clear.   Man made climate change behaves differently than orbital cycles.  Orbital cycles change the amount of sunlight different parts of the earth receive while carbon emissions inherently trap heat.   The oceans were likely colder 10,000 years ago when the Sahara was green and getting lots of rain.  Anthropogenic climate forcers will make the oceans warmer.   It's a different scenario and hard to predict with any certainty. Global weather patterns are complicated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's worth pointing out that a measurable rise in CO2 helps plants retain water.  Plants retain more water during transpiration in high CO2 concentrations because their stomata don't need to open as much to get the desired CO2.   Plants still need water, but they hold onto the water they have better in higher CO2 environments.   What effect that has on the greening deserts, it's too early to say.   We also shouldn't confuse human efforts to withdraw more water from aquifers and make areas more green with natural greening. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencedaily.com/releases/2011/03/110303111624.htm&quot; rel=&quot;noreferrer&quot;&gt;http://www.sciencedaily.com/releases/2011/03/110303111624.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and you might think &quot;good&quot; plants hold water better, but we actually rely on plant transpiration as part of the water cycle.   Warmer air needs more water to get saturated enough for clouds to rain and if plants release less water into the air (and simultaneously there's less snow runoff), less water is returned to the air over land.  The result is increased dry areas and growing deserts, if not around the Sahara, then elsewhere.   So, even if the Sahara or parts of the Sahara get greener, other areas could see increased deserts and drought.  This effect is particularly important in areas that rely on atmospheric water vapor returned from land (not off the ocean) such as the mid-west US, much of china, parts of Australia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Over time, oceans will also be rising, warming, and acidifying.  So, any greening in arid areas will be dwarfed by other problems.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="543" LastEditDate="2015-09-15T03:23:03.790" LastActivityDate="2015-09-15T03:23:03.790" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4599" PostTypeId="1" CreationDate="2015-03-27T08:05:24.720" Score="11" ViewCount="7526" Body="&lt;p&gt;The old adage &quot;The calm before the storm&quot; certainly has an observational scientific meaning to it -- something that many (including myself) have experienced -- that on a hot summer's day, when a change in the weather starts rolling in, humidity rises, but it becomes very calm with little to no wind, before the storm begins. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(This of course is not the only phenomenon associated with a change in weather).&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What confluence of meteorological factors results in the 'calm before the storm'?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="13386" LastEditorDisplayName="user889" LastEditDate="2018-07-15T14:39:37.217" LastActivityDate="2018-07-15T14:39:37.217" Title="What causes the 'calm before the storm'?" Tags="|meteorology|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="4600" PostTypeId="1" AcceptedAnswerId="4604" CreationDate="2015-03-27T15:32:18.450" Score="14" ViewCount="3465" Body="&lt;p&gt;As I understand it, greenhouse gases absorb infrared radiation from the sun.  Much of that radiation would otherwise continue and be absorbed on the planet surface in the ocean or on land.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If CO&lt;sub&gt;2&lt;/sub&gt; increases are causing the oceans to warm, does that happen mainly by convection?  It's counter intuitive to me to think about air convection having that much effect on ocean temperatures.  Why wouldn't greenhouse gases' soaking up of infrared instead cool the oceans, that would otherwise be warmed by the radiation?&lt;/p&gt;&#xA;" OwnerUserId="2727" LastEditorUserId="543" LastEditorDisplayName="user889" LastEditDate="2017-02-20T17:42:48.313" LastActivityDate="2022-07-19T01:21:06.997" Title="Why do greenhouse gases affect ocean temperature so much?" Tags="|atmosphere|climate|climate-change|co2|" AnswerCount="5" CommentCount="0" FavoriteCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4601" PostTypeId="2" ParentId="4599" CreationDate="2015-03-27T19:02:40.650" Score="8" Body="&lt;p&gt;Quoting from &lt;a href=&quot;http://science.howstuffworks.com/nature/climate-weather/storms/calm-before-storm1.htm&quot;&gt;Is there really a &quot;calm before the storm&quot;?&lt;/a&gt; at &lt;a href=&quot;http://www.howstuffworks.com/&quot;&gt;howstuffworks.com&lt;/a&gt; this &lt;em&gt;sometimes&lt;/em&gt; happens (&quot;&lt;em&gt;Other storms skip the calm and proudly announce their presence by instantly unleashing bad weather&lt;/em&gt;&quot;).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;As warm, moist air is pulled into a storm system, it leaves a&#xA;  low-pressure vacuum in its wake. The air travels up through the storm&#xA;  cloud and helps to fuel it. The updrafts in the storm, however,&#xA;  quickly carry the air upward, and when it reaches the top of the cloud&#xA;  mass, this warm moist air gets spit out at the top. This air is sent&#xA;  rolling out over the big, anvil-shaped head of the thunderclouds or&#xA;  the roiling arms of hurricanes. From there, the air descends -- drawn&#xA;  back toward lower altitudes by the very vacuum its departure created&#xA;  in the first place.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That descending air becomes warmer and drier which is relatively stable, and once it blankets a region, it stabilizes that air in turn. This causes the calm before a storm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Follow the link so see a more extended explanation with graphics.&lt;/p&gt;&#xA;" OwnerUserId="595" LastEditorUserId="20" LastEditDate="2015-03-27T21:57:44.097" LastActivityDate="2015-03-27T21:57:44.097" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4602" PostTypeId="2" ParentId="4600" CreationDate="2015-03-27T19:32:33.107" Score="16" Body="&lt;p&gt;No, greenhouse gases do not absorb infrared radiation from the sun... the Earth is really the source of infrared.  The amount of infrared energy from the sun that reaches Earth is insignificant.  Visible light from the sun heats the Earth, NOT infrared light.  The visible light passes through the atmosphere and is absorbed by the surface of the Earth.  Then, the Earth re-radiates that energy back into the atmosphere in the form of heat (aka infrared radiation).  The infrared radiates back into space, but if there are infrared absorbers in the atmosphere, the energy is not lost to space.  That has a net warming effect.  In fact the Earth needs greenhouse gases, or we would all be frozen.  It is a delicate balance between GHG concentrations and climate effects on the hydrologic cycle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is important to note that ocean water expands in response to temperature increase... so even just a modest increase in ocean temperature can lead to significant sea level changes.  Human civilization is thus directly affected by oceanic temperature increase due to sea-level rise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a side note, the absorption of carbon into the ocean is really of more environmental concern than the actual heating of the ocean, in terms of acidic effects on the marine ecosystems.  The ocean absorbs roughly half the carbon emitted into the atmosphere and there are areas already seeing the negative effects of acidification.  &lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2015-03-27T19:39:12.170" LastActivityDate="2015-03-27T19:39:12.170" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4603" PostTypeId="2" ParentId="4600" CreationDate="2015-03-27T22:53:56.100" Score="12" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;As I understand it, greenhouse gases absorb infrared radiation from the sun.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That's not correct. The atmosphere is more or less transparent to the incoming solar radiation. About 29% of the incoming solar radiation is reflected back into space (that's the Earth's albedo). The remaining 71%  is absorbed. Clouds and the atmosphere are responsible for a bit less than a third of that absorption. The other two thirds is absorbed by the Earth's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This absorption is not where the greenhouse gases come into play.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The greenhouse gases instead come into play as a multi-layered blanket that keeps the surface of the Earth from cooling off. By way of analogy, suppose you went camping in the desert. While deserts can get quite hot during the day, they get surprisingly cool at night. A blanket protects you against those cool desert nights. While the blanket doesn't generate heat, it very much does slow down the heat transfer. It does this by emitting half of its thermal energy upward, half downward. This back-radiation makes your body remain warm. Add more blankets and you get even more protection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While our atmosphere is more or less transparent in the visible range, the greenhouse gases make it opaque in thermal infrared. It is so opaque in the thermal infrared that our atmosphere acts as the equivalent of a multi-layer blanket. The solar radiation absorbed by Earth's surface is a bit less than 1/3 of the total energy received by the surface. The other two thirds is back-radiation from the Earth's atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This topic is the subject of the Earth's radiation budget. Thanks to satellites, atmospheric scientists have been investigating the radiation budget for about half a century.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/b/bb/The-NASA-Earth%27s-Energy-Budget-Poster-Radiant-Energy-System-satellite-infrared-radiation-fluxes.jpg/1552px-The-NASA-Earth%27s-Energy-Budget-Poster-Radiant-Energy-System-satellite-infrared-radiation-fluxes.jpg&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="-1" LastEditDate="2017-03-10T09:42:50.713" LastActivityDate="2015-03-27T22:53:56.100" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4604" PostTypeId="2" ParentId="4600" CreationDate="2015-03-28T01:56:18.703" Score="6" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;If CO2 increases are causing the oceans to warm, does that happen&#xA;  mainly by convection, then? It's counter intuitive to me to think&#xA;  about air convection having that much effect on ocean temperatures.&#xA;  Why wouldn't greenhouse gases' soaking up of infrared instead cool the&#xA;  oceans, that would otherwise be warmed by the radiation?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In a nutshell, and as pointed out above, CO2 and the greenhouse effect primarily warms the lower atmosphere.   After that it's all circulation.    Warm air over the colder ocean is the cause for heat transfer into the ocean.   The same thing happens every summer, when the warm air gradually warms up the ocean - which is why the ocean is colder in June than September.  Warm air warms the ocean - but it takes time.   Cold air cools the ocean - this also takes time.   The ocean is a very effective heat sink.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's the heat transfer between the air and the ocean that causes most of the heat from climate change to go into the ocean.   It's not correct to say the ocean is warming more, cause it's actually warming much more slowly, but it takes about 1000 times as much heat to warm the top half of the ocean than it does to warm the troposphere.   So the ocean ends up trapping 90% of the heat trapped from man made climate change.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2015-03-28T01:56:18.703" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4605" PostTypeId="2" ParentId="3136" CreationDate="2015-03-28T12:26:45.757" Score="5" Body="&lt;p&gt;Recent observations and modelling by Plane et al. (2015) and Plane et al. (2014) have described the most likely mechanisms for why potassium has its unique semi-annual variability, with a small summertime maximum and minima occurring at the equinoxes (Plane et al. 2015).  The semi-annual variability is consistent across the globe (Plane et al. 2014).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In both papers, the cause of the unique semi-annual variability are narrowed down to 2 main atmospheric chemical dynamics, based in no small part on unique K chemical properties:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;em&gt;Note: MLT = Mesosphere-Lower Thermosphere&lt;/em&gt;)&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;In summertime, the maxima observed is due to the cooler MLT temperatures being low enough to neutralise K&lt;sup&gt;+&lt;/sup&gt; ions to K.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;During the equinoxes, O is at a minima, while CO&lt;sub&gt;2&lt;/sub&gt; and H&lt;sub&gt;2&lt;/sub&gt; exhibit a maxima - so, according to Plane et al. (2015)'s model, decreasing O, while increasing CO&lt;sub&gt;2&lt;/sub&gt; and H&lt;sub&gt;2&lt;/sub&gt; causes a reaction with K to form KHCO&lt;sub&gt;3&lt;/sub&gt;, thus resulting in K being at a minima.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;According to their models, KHCO&lt;sub&gt;3&lt;/sub&gt; returns to K by largely temperature independent photolysis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plane et al. (2014) describe there is a slight decrease in K in high latitudes in the presence of polar mesospheric clouds. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plane et al. 2015, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2014GL060334/full&quot; rel=&quot;nofollow&quot;&gt;Resolving the strange behavior of extraterrestrial potassium in the upper atmosphere&lt;/a&gt;, &lt;em&gt;Geophysical Research Letters&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plane et al. 2014, &lt;a href=&quot;http://pubs.acs.org/doi/full/10.1021/cr500501m&quot; rel=&quot;nofollow&quot;&gt;The Mesosphere and Metals: Chemistry and Changes&lt;/a&gt;, &lt;em&gt;Chemical Reviews&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-03-29T06:46:34.170" LastActivityDate="2015-03-29T06:46:34.170" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4606" PostTypeId="2" ParentId="2914" CreationDate="2015-03-28T21:13:15.480" Score="7" Body="&lt;p&gt;Stable isotope signatures in igneous rock (primarily $\delta$&lt;sup&gt;18&lt;/sup&gt;O) can be affected by climate, but the effect is complicated and unreliable enough that I doubt it can really be used to say much about palaeoclimate. You might be interested in my friend Lara Owens' &lt;a href=&quot;http://www.ees.nmt.edu/outside/alumni/papers/2013d_owens_lb.pdf&quot; rel=&quot;nofollow&quot;&gt;dissertation&lt;/a&gt; in which she considers the influence of climate on $\delta$&lt;sup&gt;18&lt;/sup&gt;O in lava from Mt Erebus, Antarctica. Oxygen isotopes in Erebus precipitation are some of the lightest in the world, and she suggests that this water, after incorporation into a hydrothermal system whose rocks were later assimilated into magma, caused the anomalous $\delta$&lt;sup&gt;18&lt;/sup&gt;O in some of the samples.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It would be interesting to see if there is a global geographic trend in similar anomalies, but I haven't heard of anyone trying that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A more direct way that igneous rocks can record paleoclimate is through the effects that the atmosphere can have on pyroclastic deposits. Isopleth maps often can reveal the direction the wind was blowing during the eruption. Clast morphologies might even tell you the weather -- I'm thinking of accretionary lapilli, which form when an ash-rich eruption plume encounters a rain storm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In conclusion, you might be able to glean a few data points here and there, but nothing comparable to the amazing records available in sedimentary rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit to add:&lt;/strong&gt; I just went to a lecture by Jay Quade about figuring out the timing of uplift in the Andes, and whether it came before or after the Atacama became hyperarid. Among many other geochemical tools, he used $\delta$&lt;sup&gt;2&lt;/sup&gt;H in hydration waters on tephra, primarily to figure out palaeoaltitudes. He said he thinks the relationship between $\delta$&lt;sup&gt;2&lt;/sup&gt;H and altitude has been fairly constant over the period of investigation (back to 50 mya).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit to add:&lt;/strong&gt; I had forgotten to point out that subglacial eruption deposits are often distinctive (tuyas, hyaloclastites, pillow basalts). Wherever these deposits are found, you know a glacier or ice sheet was present and if you can date the rock then you know when there was a glacier there. Some recent work has suggested that you can even figure out the thickness of the glacier using the concentration of dissolved gasses in melt inclusions in the subglacially erupted lava flow.&lt;/p&gt;&#xA;" OwnerUserId="63" LastEditorUserId="63" LastEditDate="2015-08-25T01:45:39.267" LastActivityDate="2015-08-25T01:45:39.267" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4607" PostTypeId="2" ParentId="4213" CreationDate="2015-03-29T00:01:35.233" Score="4" Body="&lt;p&gt;Observations and geochemical measurements presented in a study published soon after the article in the question, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2005GC001152/full&quot; rel=&quot;nofollow&quot;&gt;Submarine venting of liquid carbon dioxide on a Mariana Arc volcano&lt;/a&gt; (Lupton et al. 2006) sheds considerable light on the processes involved in the unique Champagne vent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The key unique features of the Champagne Vent are the presence of CO&lt;sub&gt;2&lt;/sub&gt; droplets and the CO&lt;sub&gt;2&lt;/sub&gt; concentration - 2.7 moles/kg - the highest for any underwater hydrothermal vent. This concentration is also supersaturated, being considerably higher than what should be possible at the temperature and pressure present at the vent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The proposed model, based on Lupton et al's observations and measurements, suggests that there is a subsurface layer of CO&lt;sub&gt;2&lt;/sub&gt; liquid and hydrates that is penetrated by the vent, resulting in the CO&lt;sub&gt;2&lt;/sub&gt; becoming entrained in the hydrothermal fluids, providing for the observed 'cold' CO&lt;sub&gt;2&lt;/sub&gt; droplets and also increasing the concentration to supersaturation levels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lupton et al. also explain that from geochemical analyses, the source of the carbon is mostly (90%) from subducted carbonate melt, with a small amount coming organic matter and mantle derived carbon.  Further, chemical measurements reported in the later research &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2008GC002141/full&quot; rel=&quot;nofollow&quot;&gt;Chemistry of hydrothermal plumes above submarine volcanoes of the Mariana Arc&lt;/a&gt; (Resing et al. 2009) indicate that there is an absence of chemical reactions between the host rocks and the CO&lt;sub&gt;2&lt;/sub&gt; and further suggest that the magma chamber is deep within the NW Eifuku volcano (Champagne Vent source) and the gases rise into colder, older substrate.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorDisplayName="user889" LastEditDate="2015-03-29T06:44:38.470" LastActivityDate="2015-03-29T06:44:38.470" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4608" PostTypeId="2" ParentId="4564" CreationDate="2015-03-29T00:16:58.497" Score="3" Body="&lt;p&gt;My best estimate on what would happen is the following: &lt;br&gt;&#xA; - At the &lt;a href=&quot;http://en.wikipedia.org/wiki/Terminator_(solar)&quot; rel=&quot;nofollow&quot;&gt;twilight zone&lt;/a&gt; there would be tremendously fierce and constant windstorms as the heavier cold air rushed from the dark side to displace the lighter air warmed by the Sun. &lt;br&gt;&#xA; - Additionally, the wind patterns would generally align themselves towards and away from the twilight zone. &lt;br&gt;&#xA; - Over a millennia, the storms would probably carve canyons and deep scars into the face of the planet along the twilight zone.&lt;br&gt;&#xA; - Relative calm would be found in the area closest to the Sun as well as farthest from the Sun. &lt;br&gt;&#xA; - If the planet were inhabited, the inhabitant would probably be locked to either the light side or the dark side unless they had some method of navigating through or around the storms.&lt;br&gt;&#xA; - I don't know if it would rain or not, but if it did, it would definitely only rain on the side facing the Sun, as the other side would be perpetually frozen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not a meteorologist, this is just a thought exercise, so I don't know how accurate any of this is (although I do have some basic knowledge of meteorology).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT&lt;/strong&gt;: I found &lt;a href=&quot;http://en.wikipedia.org/wiki/Habitability_of_red_dwarf_systems#Tidal_effects&quot; rel=&quot;nofollow&quot;&gt;this wikipedia article&lt;/a&gt;, which seems to support my theories.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Due to differential heating, it was argued, a tidally locked planet would experience fierce winds blowing continually towards the night side[citation needed] with permanent torrential rain at the point directly facing the local star, the subsolar point. In the opinion of one author this makes complex life improbable. Plant life would have to adapt to the constant gale, for example by anchoring securely into the soil and sprouting long flexible leaves that do not snap. Animals would rely on infrared vision, as signaling by calls or scents would be difficult over the din of the planet-wide gale. Underwater life would, however, be protected from fierce winds and flares, and vast blooms of black photosynthetic plankton and algae could support the sea life.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2729" LastEditorUserId="2729" LastEditDate="2015-03-29T00:22:56.403" LastActivityDate="2015-03-29T00:22:56.403" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="4609" PostTypeId="1" AcceptedAnswerId="4611" CreationDate="2015-03-29T00:39:46.230" Score="14" ViewCount="2699" Body="&lt;p&gt;Was Earth's sea-floor always carved with the numerous geological features that we see today, or was it at some point flat and boring as Mars is today?&lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorDisplayName="user20559" LastEditDate="2021-09-23T07:03:54.337" LastActivityDate="2021-09-23T07:03:54.337" Title="Earth's ocean basins" Tags="|geology|oceanography|planetary-science|sea-floor|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4610" PostTypeId="2" ParentId="2498" CreationDate="2015-03-29T01:49:55.563" Score="7" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Too much tilt will cause extreme seasons, and that will lead to an extreme climate.  For a planet with a tilt of 90˚ - that is, lying on its side - the Arctic and Antarctic circles coincide with the equator, and there are neither tropical nor temperate zones.  Seasons are extreme indeed; over nearly half the planet the Sun would never set during the summer, and never rise during the winter.  Only during spring and fall, when it would shine from the side, would the Sun rise and set as we're used to.  &lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/158297134X&quot; rel=&quot;nofollow noreferrer&quot;&gt;(World-Building - By: Stephen Gillett)&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In essence, the weather patterns would alternate from season to season from relatively normal, as all sides of the planet receive equal light, to extremely fierce (matching that of a &lt;a href=&quot;http://en.wikipedia.org/wiki/Tidal_locking&quot; rel=&quot;nofollow noreferrer&quot;&gt;tidally locked planet&lt;/a&gt;); however, due to the spinning of the planet, the &lt;a href=&quot;http://en.wikipedia.org/wiki/Coriolis_effect&quot; rel=&quot;nofollow noreferrer&quot;&gt;coriolis effect&lt;/a&gt; would still be present.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/4564/how-would-weather-change-on-a-tidally-locked-terrestrial-planet/4608#4608&quot;&gt;Weather Patterns of a tidally locked planet&lt;/a&gt;&lt;br&gt;&#xA;  - At the &lt;a href=&quot;http://en.wikipedia.org/wiki/Terminator_(solar)&quot; rel=&quot;nofollow noreferrer&quot;&gt;twilight zone&lt;/a&gt; there would be tremendously fierce and constant windstorms as the heavier cold air rushed from the dark side to displace the lighter air warmed by the Sun. &lt;br&gt;&#xA;  - Additionally, the wind patterns would generally align themselves towards and away from the twilight zone. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;For the sake of discussion, let's say that &quot;winter&quot; is when the South Pole faces the Sun.  During winter, the South Pole would completely thaw, and the North Pole would completely freeze.  In Spring, both poles would be in the twilight zone with one pole beginning to cool as the other begins to thaw.  During the Summer, the exact opposite would happen.  The North Pole would thaw and the South Pole would freeze, and so on and so forth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The repeated freezing and thawing of the oceans would definitely have a profound effect on the climate, possibly permanently cooling the planet as the &lt;a href=&quot;http://en.wikipedia.org/wiki/Albedo&quot; rel=&quot;nofollow noreferrer&quot;&gt;albedo&lt;/a&gt; (reflective coefficient) of ice is much greater than that of water.  At the very least, it would heavily effect the ocean and air currents which play a major role in weather patterns.&lt;/p&gt;&#xA;" OwnerUserId="2729" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-03-29T01:49:55.563" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4611" PostTypeId="2" ParentId="4609" CreationDate="2015-03-29T02:23:57.283" Score="11" Body="&lt;p&gt;Yes, in terms of appearances (as in your question), the Earth's ocean basins have more than likely have been carved with features of some kind or another throughout Earth's history; however, the Martian surface is not featureless - not even close.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason being that the geological evidence suggests that &lt;a href=&quot;https://earthscience.stackexchange.com/questions/418/how-did-tectonic-plates-originally-come-to-form&quot;&gt;plate tectonics has been going on for much of the Earth's history&lt;/a&gt;, a mechanism that seems not to be present on Mars - many observations and subsequent models show that the plates have been in motion for much of the history of the planet - resulting in trenches and underwater (and above water) volcanoes (subduction ones), ridges (sea floor spreading). Additionally, hot spot activity has given rise to numerous sea mounts, such as the &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2415/what-caused-the-bend-in-the-emperor-hawaii-chain-of-islands-45-million-years-ag&quot;&gt;Emperor-Hawaii seamount chain&lt;/a&gt;.  These features often taken millions of years to fully develop.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even though oceanic crust is recycled through plate tectonics, it could be assumed that these processes have formed similar ocean-floor-scapes on occasions over a long period of the Earth's history.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the main differences is that the processes that form these features on Earth have been, overall, semi-continuous on Earth - whereas on Mars, these processes, if started, died out a considerable time ago.&lt;/p&gt;&#xA;" OwnerDisplayName="user889" LastEditorUserId="-1" LastEditorDisplayName="user889" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-03-30T21:56:50.510" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="4612" PostTypeId="1" CreationDate="2015-03-29T06:36:10.610" Score="13" ViewCount="24735" Body="&lt;p&gt;The climatic system can be divided into five main components: the atmosphere, the hydrosphere, the lithosphere, the cryosphere and the biosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All these physical systems operate at different time and spatial scales. The lithosphere, that makes the uppermost, rigid layer of the earth, is formed by a few dozens of tectonic plates that move laterally while resting on the Earth's fluid mantle (&lt;em&gt;plate tectonics&lt;/em&gt;). The collision between lithospheric plates builds mountains, and their separation forms ocean basins where sediment is accumulated, on timescales of tens to hundreds of millions of years. Hence, it is considered that its effect on climate change is not on the same timescale as the other components of the system and is not given as much attention.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Despite its low effect on the historical time-scales, undoubtedly, it poses a load on the system. Note that I am not interested on events that can in fact interact with the timescales of other climatic components. For example when land masses ocupied positions near the poles and the effect of the resulting increase in glaciation can be on the same time scale as other non-lithospheric physical phenomena. Nor am I interested in singular volcanic eruptions or activity of that sort. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am interested in how the processes such as continental drift, mountain growth, and erosion, affect climate evolution. &lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="1379" LastEditorDisplayName="user889" LastEditDate="2016-01-16T17:22:37.550" LastActivityDate="2016-02-20T22:23:30.080" Title="How has and how does the lithosphere affect climate change?" Tags="|climate|climate-change|paleoclimatology|lithosphere|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4613" PostTypeId="1" AcceptedAnswerId="4616" CreationDate="2015-03-29T14:39:52.970" Score="6" ViewCount="362" Body="&lt;p&gt;I'm slightly confused by how thermohaline circulation works in the Earth's oceans. Is it different  for surface water as opposed to deep water? I thought that warm water from the equator is transported to the poles, cools down, and then returns to lower latitudes. Is my thinking incorrect? Isn't water denser near the equator because of higher salinity? How does this impact the ocean circulation? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;" OwnerUserId="2604" LastActivityDate="2015-03-29T23:35:03.113" Title="Thermohaline Circulation in the Oceans" Tags="|ocean|thermohaline-circulation|salinity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4614" PostTypeId="2" ParentId="4609" CreationDate="2015-03-29T21:58:53.300" Score="9" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Was the Earth seafloor always carved with the numerous geological features that we see today?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Absolutely not. The seafloor is where plate tectonics is starts and ends. The seafloor is extremely dynamic and is incredibly young compared the age of the Earth. Most of the seafloor is less than 200 million years old. The very oldest oceanic crust is in the Mediterranean, and that's only about 270 million years old. That's tiny compared to the 4.5 to 4.6 billion years the Earth has been in existence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oceanic crust forms at mid-ocean ridges and disappears in subduction zones. This is what makes the oceans so dynamic in geological terms. There are no corresponding processes for continental crust. Continental crust is in general quite old compared to oceanic crust.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Depicted below is a map from NOAA that portrays the age of the oceanic crust. Note how the mid-oceanic ridge plays a dominant role.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://www.ngdc.noaa.gov/mgg/image/images/WorldCrustalAge.jpg&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;&lt;strong&gt;Update&lt;/strong&gt;&lt;br&gt;&#xA;The sea floor has not always been carved with the numerous geological features that we see today. In the article &lt;a href=&quot;http://www.sciencemag.org/content/319/5859/85&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;Intermittent plate tectonics?&quot; &lt;em&gt;Science&lt;/em&gt; 319.5859 (2008)&lt;/a&gt;, Paul Silver and Mark Behn show that plate tectonics has come to a temporary standstill at times in the Earth's past. The deep ocean trenches that separate two continental plates on a collision course with one another disappear when those plates do collide. When this happened globally (e.g., the formation of a single supercontinent), the dominant slab-pull mechanism faltered, and that in turn shut down the mechanisms that form the mid-oceanic ridges. The mid-oceanic ridges slowly collapsed under their own weight. The end result was an ocean floor devoid of features.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This apparently happened with the formation of Pangea. The collapse of the mid-oceanic ridges resulted in a vastly reduced sea level. Sea level at the end of the Permian / start of the Triassic was 300 to 400 meters below the present day sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Ocean floor features&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The features of the ocean floor include&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The abyssal plain.&lt;br&gt;&#xA;The vast majority of the ocean floor comprises the deep, flat, and featureless abyssal plain. The abyssal plain is one of the two features of the ocean floor that has been present since shortly after the continents and oceans first formed.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Continental margins.&lt;br&gt;&#xA;The other ever-present feature of the ocean floor is the continental margins. Continental crust is considerably less dense and considerably thicker than is the oceanic crust that underlies most of the ocean floor.   This difference in density and thickness is why the Earth has continents.&#xA;The transition from oceanic crust to continental crust is rather sharp; the continental slope marks the boundary between the two. The continental shelf is submerged continental crust between the continent and the continental rise. Oftentimes runoff debris from the continent gets deposited at the base of the continental slope; this is the continental rise. The continental shelf, continental slope, and continental rise are collectively called the continental margin.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Subduction zones.&lt;br&gt;&#xA;Subduction zones occur at convergent boundaries between an oceanic plate collides and another plate. The common characteristic of subduction zones is a deep oceanic trench. The deepest parts of the oceans are at subduction zones. Subduction zones are oftentimes associated with island arcs, typically volcanic.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The mid-oceanic ridge.&lt;br&gt;&#xA;Long hidden from humankind, this is by far the longest mountain chain in the world. The mid-oceanic ridge is the deep red areas in the above map. This is where new oceanic crust is created.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&quot;Hotspot&quot; volcanos and other oddities.&lt;br&gt;&#xA;The Hawaiian islands, the Ninety-East Ridge, and other oddities well removed from plate boundaries -- what explains these? A hypothesis was raised in 1963, that these were caused by &quot;mantle plumes&quot;. This was widely accepted for a while, but is losing favor. Whether mantle plumes exist remains one of the most hotly contested topics in geology today.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Per Silver and Behn, and many subsequent authors, subduction zones and the mid-oceanic ridges are not ever-present features. What motivated Silver and Behn was that prior to India's collision into Asia, there used to be a sizable subduction zone between the Indian and Eurasian plates. That subduction zone has been replaced by the Himalaya. No new subduction zone has appeared in the last 50 million years to take place of that lost subduction zone. Supercontinents assemble by subduction followed by continental collision. It stood to reason to Silver and Behn (and many others) that the assembly of a supercontinent would be marked by drastically reduced subduction and mid-ocean spreading. During those periods of reduced plate tectonics, the deep ocean trenches would close and the mid-oceanic ridges would collapse under their own weight.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="-1" LastEditDate="2017-03-10T09:42:50.730" LastActivityDate="2015-03-31T15:35:39.227" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4615" PostTypeId="2" ParentId="4612" CreationDate="2015-03-29T23:09:15.863" Score="11" Body="&lt;p&gt;This is a huge and interesting topic. &#xA;Certainly there are many ways the climate is affected by the lithosphere (and also what is going on in the asthenosphere). The lithosphere is naturally also affected by the climate. I find it difficult to distinguish the 'components' as matter and energy can flow from biosphere to lithosphere and from hydrosphere to atmosphere etc. Somehow it might be appealing to think about lithosphere as a slow 'component' but keep in mind that the atmospheric circulation have been much more stable than the locations of the continents. Deserts have been in the same latitudes, even as continents have been moving. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A few areas of influence to consider: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Location of landmasses affects ocean currents and climate &lt;a href=&quot;http://www.whoi.edu/oceanus/feature/how-the-isthmus-of-panama-put-ice-in-the-arctic&quot;&gt;e.g. closing of Isthmus of Panama&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Supercontinent#Supercontinental_climate&quot;&gt;Supercontinents&lt;/a&gt; certainly had a very different climate than what we experience today. &lt;/li&gt;&#xA;&lt;li&gt;Uplifts and orogenies can have local, &lt;a href=&quot;http://link.springer.com/article/10.1007%2Fs11434-013-5987-8&quot;&gt;regional&lt;/a&gt; and &lt;a href=&quot;http://geology.gsapubs.org/content/36/12/1003.full&quot;&gt;global&lt;/a&gt; effects. &lt;/li&gt;&#xA;&lt;li&gt;Carbonates in the lithosphere plays an important role the carbon cycle. See e.g. &lt;a href=&quot;http://andy.seao2.info/pubs/ridgwell_and_zeebe_2005.pdf&quot;&gt;this&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Rate of vulcanism also follows tectonic conditions. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2015-03-30T22:53:38.463" LastActivityDate="2015-03-30T22:53:38.463" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4616" PostTypeId="2" ParentId="4613" CreationDate="2015-03-29T23:35:03.113" Score="9" Body="&lt;p&gt;Salinity and temperature both affects the density of sea water. When water with a fixed salinity cools down, it becomes heavier and sinks. In the same way, when vapor or ice removes water from sea water, the remains is more saline and heavier. &#xA;Thermohaline circulation can work as you describe. Surface water in the tropics is saline, due to evaporation, but warm due to high temperature in the atmosphere and therefor low density. As it reach colder climate (less solar energy per area), it cools down and the high salinity makes it sink. Surface water in polar regions also get heavier as ice is formed of water and leave the salt behind in the sea. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is very simplified model, you can read more on the topic &lt;a href=&quot;http://oceanmotion.org/html/background/ocean-conveyor-belt.htm&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;http://oceanservice.noaa.gov/education/tutorial_currents/05conveyor1.html&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2536" LastActivityDate="2015-03-29T23:35:03.113" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4617" PostTypeId="2" ParentId="4570" CreationDate="2015-03-30T09:36:54.050" Score="2" Body="&lt;p&gt;The way I imagine this phenomenon is illustrated in the picture below. I have to warn you that it lacks scientific accuracy and is &lt;strong&gt;just a simple way to imagine&lt;/strong&gt; the effects we observe on a reflective boundary. However, it can be useful as a simple model you can easily imagine.&lt;br&gt;&#xA;In the upper picture you can see an illustration of a &lt;a href=&quot;http://en.wikipedia.org/wiki/Reflection_seismology#Reflection_and_transmission_at_non-normal_incidence&quot; rel=&quot;nofollow noreferrer&quot;&gt;reflection event&lt;/a&gt; at a horizontal boundary.&lt;br&gt;&#xA;The lower picture illustrates how the vector of particle motion in a down-going P-wave is 'decomposed' into two vectors. First component is a vector of particle motion in an up-going S-wave, the second corresponds to particle motion in an up-going P-wave.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once again, &lt;strong&gt;this is not how the rays exactly behave&lt;/strong&gt; in a reflection event. Here we do not take into account transmitted waves and lots of other factors. Nevertheless, sometimes you can use this 'approximation' because it satisfies two conditions:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;At normal incidence, there is no mode conversion (shear wave does not appear)&lt;/li&gt;&#xA;&lt;li&gt;As the incident angle increases, the amount of shear-wave energy increases too.    &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;These effects are also observed in real life.&lt;br&gt;&#xA;Exact description of a reflection event on a plane boundary, as &lt;a href=&quot;https://earthscience.stackexchange.com/users/70/kwinkunks&quot;&gt;kwinkunks&lt;/a&gt; has  mentioned above, is given by Zoeppritz equations. They take into account all details and are widely-used. No doubt, they are much more difficult (but physically correct!) than a simple sketch I suggest.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/QkMAl.png&quot; alt=&quot;a very simple illustration of mode conversion&quot;&gt;. &lt;/p&gt;&#xA;" OwnerUserId="506" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-03-31T23:05:00.530" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4618" PostTypeId="2" ParentId="4612" CreationDate="2015-03-30T11:58:28.617" Score="5" Body="&lt;p&gt;It's not easily answered, but I think, given the criteria you've laid out, the effects are generally pretty small.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I am not interested on events that can in fact interact with the&#xA;  timescales of other climatic components. For example when land masses&#xA;  ocupied positions near the poles and the effect of the resulting&#xA;  increase in glaciation can be on the same time scale as other&#xA;  non-lithospheric physical phenomena. Nor am I interested in singular&#xA;  volcanic eruptions or activity of that sort. I am interested in how&#xA;  the processes such as continental drift, mountain forming, erosion,&#xA;  affects climate change.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Can I assume that you want to ignore events like the closing of the Isthmus of Panama which may have had a significant climate effect?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's hard to say with any precision or absolute certainty but I don't think the climate cares much if mountains are growing or shrinking, it cares where the mountains are and how high they are, but the actual movement of plates and continents in and of itself shouldn't have a big effect on climate.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I say that is a few reasons.   1) we've had two significant tectonic events recently, one just off Japan, where Japan moved 3 feet closer to California and there was the huge, devastating tsunami, and that happened at a time when we've been monitoring climate change very closely and I've not seen a single article that suggested that the Japanese earthquake played a key role in 2011's weather, much less long term.  Same with the large earthquake off Indonesia and Thailand a few years before, but the 1991 volcanic eruption (Pinatubo) did have a measured climate effect.   Here's an article that suggests the same:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://blogs.ei.columbia.edu/2011/04/28/can-big-earthquakes-disrupt-world-weather/&quot; rel=&quot;noreferrer&quot;&gt;http://blogs.ei.columbia.edu/2011/04/28/can-big-earthquakes-disrupt-world-weather/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The atmosphere and oceans get energy every minute of every day from the inside of the earth, but even during the largest upheavals, there's no clear change in climate for the single year, much less long term.    Volcanoes which release a lot of heat into the atmosphere have a cooling effect, not a warming effect, because of particulates and sulfates that block sunlight following the Volcano - so I have a hard time seeing that heat or movement from the earth directly effects climate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's worth noting that particular events can impact climate - like the Isthmus of Panama, mentioned in the other answer, or this one, below. which was far more sudden than the formation of the Isthmus of Panama, though the effect was also smaller and perhaps temporary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://climate.gov/news-features/features/day-yesterday-when-abrupt-climate-change-came-chesapeake-bay&quot; rel=&quot;noreferrer&quot;&gt;https://climate.gov/news-features/features/day-yesterday-when-abrupt-climate-change-came-chesapeake-bay&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and while the Isthmus of Panama is often credited for the beginning of the ice age cycle, it's worth noting that the Himalayas are quite young.  I couldn't find an exact date, but they began growing about 10 million years ago and may have had a significant effect on climate over the last 5 million years as well.    So, specific events, like the drifting of Antarctica over the south pole (30 million years ago), the crashing of India into Asia (10 million years ago) and the separation of the Atlantic and Pacific by the land bridge in Panama (3 million years ago), each may have had significant climate effects, but the general movement of continental plates and gradual rising of mountains in and of itself, I don't see why that would affect climate much.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fastest and most significant recent changes to the shape and altitude of land isn't the growth or erosion of mountains at all, but it's glaciers.   Half of North America being covered in 1.5 miles of ice likely had a significant effect on climate, not just because of albedo but also, that much change in altitude over so much land effects weather patterns and probobly global climate too.   (see article below).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.bristol.ac.uk/news/2014/november/heinrich-events-and-climate-change.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.bristol.ac.uk/news/2014/november/heinrich-events-and-climate-change.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, my skepticism that gradual changes in plate movement and mountain growth or erosion effects climate is because there's no good evidence that it does, at least not short term.  Changes over millions of years - yes.   But on a smaller scale, I don't see it.   Certainly changes can take much less than millions of years if there's a specific bottleneck that's either formed or undone, like the Isthmus of Panama, or, the black sea deluge / expansion (possibly the flood of Noah and Gilgamesh), which was likely due to the breaking of a natural dam, though I'm not sure if that one truly affected global climate.   An earthquake will make a few very big waves but it won't change ocean currents, unless it creates a blockade or opens up a major spillway of some kind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Changes in climate over the last 2.5 million years have been linked to orbital cycles, changes in CO2, the occasional very big volcano (more temporary), and, to a smaller extent, oceanic cycles and solar minimums, and there's some geological evidence of the occasional, fairly quick climate change without clear cause, but as far as I know, there's no good evidence that changes in tectonic forces drive climate over the short term.   Over millions of years - yes, over the shorter term, probobly not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mega our outburst floods might have some effect on climate, but those are pretty significant events, easily comparable to a very large volcano and no outburst floods have happened in the last 7,000 years or so.   It's also worth pointing out that while there's no likeliness that one will happen soon, we could see an outburst flood at some point in the next century or millennia, as a result of man made climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Outburst_flood&quot; rel=&quot;noreferrer&quot;&gt;http://en.wikipedia.org/wiki/Outburst_flood&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also thought this was interesting, though it's not clear what effect it had on climate:   &lt;a href=&quot;http://phys.org/news179598629.html&quot; rel=&quot;noreferrer&quot;&gt;http://phys.org/news179598629.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And, granted, my answer is speculative, but I'm not sure there is an exact answer to this that isn't somewhat speculative.   Hope that wasn't too long and confusing.   :-)&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2015-03-30T11:58:28.617" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4619" PostTypeId="1" AcceptedAnswerId="4621" CreationDate="2015-03-30T02:20:23.033" Score="11" ViewCount="25853" Body="&lt;p&gt;The Aurora Borealis (commonly known as the northern lights) is a mesmerizing and captivating sight to behold, so beautiful that I just want to touch it and feel it. Should I? Could it harm me?&lt;/p&gt;&#xA;" OwnerDisplayName="user6760" LastEditorUserId="192" LastEditDate="2016-04-28T21:10:23.480" LastActivityDate="2021-06-02T22:19:54.340" Title="What woud happen to me if I touched the aurora?" Tags="|atmosphere|hypothetical|auroras|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4621" PostTypeId="2" ParentId="4619" CreationDate="2015-03-30T02:45:05.030" Score="18" Body="&lt;p&gt;The lowest reaches of an aurora is ~100 km in the air.  Your problem won't be the ionized gas, it'll be that the air pressure is close to zero.  Also, aurora are very diffuse, with at most a few glowing molecules per square centimeter.  I'm not sure at that density that you could tell you were actually in something.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you're in a spacesuit to survive the lack of oxygen, you might worry about the high-energy electrons that sometimes make it through to those altitudes, but fundamentally your problem is that you won't really be &quot;touching the aurora&quot; because you're in a space-suit and you can't really see that you're in it.&lt;/p&gt;&#xA;" OwnerUserId="1402" OwnerDisplayName="Rex Kerr" LastActivityDate="2015-03-30T02:45:05.030" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4622" PostTypeId="2" ParentId="4619" CreationDate="2015-03-30T02:45:25.933" Score="1" Body="&lt;p&gt;If you check the Wiki article on auroras, you will find:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The altitudes where auroral emissions occur were revealed by Carl Størmer and his colleagues who used cameras to triangulate more than 12,000 auroras. They discovered that most of the light is produced between 90 and 150 km above the ground, while extending at times to more than 1000 km.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, touching an aurora is sticking your hand into hard vacuum. It's likely to smart some.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whether you &quot;should&quot; or not is up to you.&lt;/p&gt;&#xA;" OwnerDisplayName="WhatRoughBeast" LastActivityDate="2015-03-30T02:45:25.933" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4623" PostTypeId="2" ParentId="4619" CreationDate="2015-03-30T02:46:03.800" Score="10" Body="&lt;p&gt;Even the extremely dim light of the aurora is accumulated from massive volumes of air.  This means that a small volume of air emits almost no light by itself.  If you were in the middle of a filament you might not even know it!  (Likely it would be visible as increased local skyglow, but would be invisible against the Earth.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly, the aurora are essentially photon emissions from nitrogen and oxygen molecules, so you can't really touch it (as much as you can 'touch' a sunbeam).  Even the gas that emits the photons is extremely tenuous.  The aurora is emitted between 90 and 150 km in altitude (i.e. mostly above the 'official' boundary of space, 100 km), so ungloving your hand inside an aurora would &lt;a href=&quot;http://en.wikipedia.org/wiki/Space_exposure&quot;&gt;likely be fatal&lt;/a&gt; (unless a fellow astronaut immediately reattaches your glove and repressurizes your suit).&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Update&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;http://www.dtic.mil/dtic/tr/fulltext/u2/a204598.pdf&quot;&gt;this document&lt;/a&gt; it seems that going to a polar orbit only increases the radiation levels by about 10x compared to a typical medium-inclination orbit, so not enough to be immediately dangerous (but you wouldn't want to put your space station in a polar orbit).  Most weather satellites have low polar orbits, I haven't heard of a higher incidence of radiation-induced failures compared to other satellites.&lt;/p&gt;&#xA;" OwnerUserId="2731" OwnerDisplayName="2012rcampion" LastActivityDate="2015-03-30T02:52:42.227" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4624" PostTypeId="2" ParentId="4619" CreationDate="2015-03-30T14:14:36.607" Score="4" Body="&lt;p&gt;As others have pointed out, you cannot really touch it as such.  What you can do, potentially, is to fly through it on a sub-orbital flight.  It might be beautiful; indeed, aurora is from a large volume, so you would likely see it all around you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, you will be bombarded with charged particles, because that's what the aurora borealis is — the solar wind impinging on the upper atmosphere.  So, get some good shielding.  Regrettably, in that case you won't see anything.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Virgin Galactic/&lt;a href=&quot;http://www.spaceportsweden.com&quot; rel=&quot;nofollow&quot;&gt;Spaceport Sweden&lt;/a&gt; were &lt;a href=&quot;http://www.esa.int/swe/ESA_in_your_country/Sweden/Virgin_Galactic_Kiruna_aer_unikt/%28print%29&quot; rel=&quot;nofollow&quot;&gt;planning to fly tourists through the aurora&lt;/a&gt; &lt;em&gt;(Swedish language page)&lt;/em&gt; in sub-orbital spaceflights.  I think they reneged on those plans after talking to local space physicsts, but I'm not sure.  If you can lay down the 200,000$ for a ticket, they might take you on a sub-orbital flight anyway.&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2015-03-30T14:14:36.607" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4625" PostTypeId="1" CreationDate="2015-03-30T15:53:06.510" Score="6" ViewCount="199" Body="&lt;p&gt;My understanding of rain shadows is that they occur in a region where year-round wind direction is the same (or nearly so), and there's a mountain range close by, such that the mountains block moisture from the lee side. This would imply a desert on the lee side.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is there anywhere on Earth where the above two conditions are met, yet no rain shadow is produced?&lt;/strong&gt; If so, what are the complex reasons for it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only thing I can think of is maybe there's a lake or big river on the other side of the mountain, serving as a source of moisture for the atmosphere as it evaporates and thus allowing rain. But are there other reasons? It would also be helpful if anyone could explain more details of the rain shadow, like how tall do mountains need to be before the shadow takes effect, and how and why deserts still experience a huge thunderstorm every 1 to 3 years.&lt;/p&gt;&#xA;" OwnerUserId="2733" LastEditorUserId="2733" LastEditDate="2015-03-31T11:50:34.340" LastActivityDate="2015-03-31T11:50:34.340" Title="Is there anywhere on Earth *without* a rain shadow where we would otherwise expect one?" Tags="|meteorology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4631" PostTypeId="1" CreationDate="2015-03-31T05:56:53.987" Score="2" ViewCount="149" Body="&lt;p&gt;I am doing a variability analysis for landcover in Western Ghats region.&lt;br&gt;&#xA;I have various vegetation classes such as:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;evergreen (needle leaf, broad leaf),&lt;/li&gt;&#xA;&lt;li&gt;decidious (needle leaf, broad leaf), &lt;/li&gt;&#xA;&lt;li&gt;shrubland (open, closed), &lt;/li&gt;&#xA;&lt;li&gt;savannah, &lt;/li&gt;&#xA;&lt;li&gt;woody savannah, &lt;/li&gt;&#xA;&lt;li&gt;grassland, &lt;/li&gt;&#xA;&lt;li&gt;mixed forest, &lt;/li&gt;&#xA;&lt;li&gt;cropland,&lt;/li&gt;&#xA;&lt;li&gt;etc.  &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I want to know the suitable temperature and rainfall conditions that these vegetation types need to thrive or survive.&lt;/p&gt;&#xA;" OwnerUserId="2738" LastEditorUserId="87" LastEditDate="2015-03-31T07:02:38.253" LastActivityDate="2015-04-01T06:26:45.123" Title="vegetation types and their required or suitable climate condition" Tags="|climate|climate-change|vegetation|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4632" PostTypeId="1" CreationDate="2015-03-31T18:43:08.657" Score="24" ViewCount="366" Body="&lt;p&gt;The methodology and equipment for palaeomagnetic studies in the 1960s and 1970s was often rather primitive by today's standards. For example, Doell and Cox (1967) imply that the standard procedure for getting a palaeomagnetic direction was simply to measure the natural remanent magnetization, and assume that it represented a reliable primary magnetization direction if it proved sufficiently resistant to one or more of the standard demagnetization techniques. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In contrast, in a modern palaeomagnetic study, I'd expect a far more elaborate methodology: ten or more AF or thermal demagnetization steps per sample (possibly with a pilot study to compare effectiveness of demagnetization methods), measuring remaining remanence at each step; inspection of data in various projections; palaeomagnetic directions obtained by fitting one or more demagnetization components using, for example, PCA (Kirschvink, 1980), Linefind (Kent et al., 1983), or some form of great-circle intersection analysis (e.g. McFadden &amp;amp; McElhinny, 1988); and rock magnetic work (e.g. coercivity spectrum analysis) to provide a better idea of what's carrying the magnetization, and when and how the magnetization components were formed. Stability tests such as the fold test or reversal test might also by employed to check the reliability of the remanence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this context, I remember once being told that some large proportion (tens of per cent) of palaeomagnetic directions determined during the early days of the field had subsequently been invalidated when sites and samples were re-analysed using modern methodologies. Occasionally I come across an individual study which explicitly invalidates an earlier one; for example, Turner et al. (1989) revised the findings of Kennett and Watkins (1974), citing  ‘serious errors in the interpretation of the results’.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've never come across a published study which attempts a quantitative survey of how often such invalidations occur. Does anyone know of any publications which provide such a review of early palaeomagnetic studies and their reproducibility -- or lack thereof?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Doell, R. R. and Cox, A. (1967). Analysis of palaeomagnetic data. In Collinson, D. W., Creer, K. M. and Runcorn, S. K., editors, &lt;em&gt;Methods in Palaeomagnetism&lt;/em&gt;, number 3 in &lt;em&gt;Developments in Solid Earth Geophysics&lt;/em&gt;, pages 340–346. Amsterdam: Elsevier.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kennett, J. P., &amp;amp; Watkins, N. D. (1974). Late Miocene—Early Pliocene paleomagnetic stratigraphy, paleoclimatology, and biostratigraphy in New Zealand. &lt;em&gt;Geological Society of America Bulletin&lt;/em&gt;, 85(9), 1385-1398.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kent, J. T., Briden, J. C., &amp;amp; Mardia, K. V. (1983). Linear and planar structure in ordered multivariate data as applied to progressive demagnetization of palaeomagnetic remanence. &lt;em&gt;Geophysical Journal International&lt;/em&gt;, 75(3), 593-621.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kirschvink, J. L. (1980). The least-squares line and plane and the analysis of palaeomagnetic data. &lt;em&gt;Geophysical Journal International&lt;/em&gt;, 62(3), 699-718.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;McFadden, P. L., &amp;amp; McElhinny, M. W. (1988). The combined analysis of remagnetization circles and direct observations in palaeomagnetism. &lt;em&gt;Earth and Planetary Science Letters&lt;/em&gt;, 87(1), 161-172.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Turner, G. M., Roberts, A. P., Laj, C., Kissel, C., Mazaud, A., Guitton, S., &amp;amp; Christoffel, D. A. (1989). New paleomagnetic results from Blind River: Revised magnetostratigraphy and tectonic rotation of the Marlborough region, South Island, New Zealand. &lt;em&gt;New Zealand journal of geology and geophysics&lt;/em&gt;, 32(2), 191-196.&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2015-10-16T17:11:11.027" LastActivityDate="2018-10-10T16:41:51.893" Title="How reliable were early measurements of palaeomagnetic directions?" Tags="|paleomagnetism|reproducibility|history-of-science|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="4633" PostTypeId="1" CreationDate="2015-03-31T20:15:51.593" Score="9" ViewCount="155" Body="&lt;p&gt;The &lt;em&gt;S&lt;/em&gt;-ratio is commonly used in rock magnetic and enviromagnetic studies to quantify the relative abundances of minerals with high and low remanent coercivities. As most frequently defined (e.g. by Evans and Heller, 2003), it is calculated as −IRM&lt;sub&gt;−300mT&lt;/sub&gt; / SIRM, where SIRM is the saturation remanence magnetization, and IRM&lt;sub&gt;−300mT&lt;/sub&gt; is the remaining magnetization after applying a 300mT reverse field to a saturated sample. In my experience, the usual procedure for determining the &lt;em&gt;S&lt;/em&gt;-ratio on a discrete sample is:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Apply a saturating field with a pulse magnetizer (or, at least, apply the strongest field possible with the equipment).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Measure the saturation magnetization in a magnetometer.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Apply the 300mT reverse field with the pulse magnetizer.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Measure the new magnetization in the magnetometer.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;On a large set of samples, things can be made quicker by working in batches and using an automated sample handling system, but it's still necessary to make two trips to the pulse magnetizer and two trips to the magnetometer. It struck me recently that, with a cryomagnetometer capable of measuring all three axes of magnetization simultaneously, a faster and more convenient procedure should be possible:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Apply the saturating field along (say) the x axis of the sample.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Apply the 300mT field along an orthogonal axis -- the y axis, say.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Measure the total magnetization vector in a 3-axis magnetometer.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Calculate the SIRM as the sum of the magnetizations along the x and y axes, and IRM&lt;sub&gt;−300mT&lt;/sub&gt; as the magnetization along the y axis.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;In fact, a similar (but far more involved) technique is already commonly applied: the triaxial IRM and thermal demagnetization protocol of Lowrie (1990), which involves applying decreasing IRMs along three orthogonal axes. In Lowrie's technique, however, there is no mention of calculating the SIRM as the sum of the orthogonal components.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is anyone already using this technique? Are there any obvious pitfalls I've missed? I am tempted to try it the next time I need to determine an &lt;em&gt;S&lt;/em&gt;-ratio, after a pilot study to confirm that the SIRMs are additive in the way I assume.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Evans, M. E. and Heller, F. (2003). &lt;em&gt;Environmental magnetism: principles and applications of enviromagnetics&lt;/em&gt;. San Diego: Academic Press.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lowrie, W. (1990). Identification of ferromagnetic minerals in a rock by coercivity and unblocking temperature properties. &lt;em&gt;Geophysical Research Letters&lt;/em&gt;, 17(2), 159–162.&lt;/p&gt;&#xA;" OwnerUserId="94" LastActivityDate="2015-03-31T20:15:51.593" Title="A faster way to measure the rock magnetic S-ratio?" Tags="|laboratory|rock-magnetism|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4634" PostTypeId="2" ParentId="4589" CreationDate="2015-03-31T22:17:13.870" Score="6" Body="&lt;p&gt;userLTK has explained that not all of the ice in the Antarctic stays frozen all the time. But perhaps there's a more basic view needed : sunlight in temperate areas melts all of the ice quite quickly, so why doesn't the same happen in Antarctica?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are a number of reasons, but the simplest (and probably most important?) is one of geometry, and the way that sunlight reaches parts of the planet's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Imagine that you are shining a torch onto a ball, where the beam from the torch is circular and much smaller than the ball.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;If the beam hits the middle of the ball, it appears as a small circle on the ball's surface.&lt;/li&gt;&#xA;&lt;li&gt;If the beam hits near the top or the bottom of the ball, it covers a larger area of the ball's surface - so that any given point receives less light.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The same is true for the earth. Near the poles, the light from the sun is &quot;skimming&quot; the planet rather than hitting at right angles, and so any given amount of energy leaving the sun is spread over a wider area near the poles, and is thus less intense. So, the amount of energy landing in Antarctica per square metre is much less than it is near the equator.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2015-03-31T22:17:13.870" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4635" PostTypeId="1" CreationDate="2015-03-31T22:25:07.317" Score="12" ViewCount="147" Body="&lt;p&gt;I'm currently working with the Soil &amp;amp; Water Assessment Tool (SWAT). My task is to model the loading of sodium chloride into streams.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One approach I would like to take is to use the point source rechour.dat file command. The file can contain several variables regarding pollutant load.&lt;br&gt;&#xA;For example:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;code&gt;ORGPHR&lt;/code&gt; is the organic P loading kg/hr,&lt;/li&gt;&#xA;&lt;li&gt;&lt;code&gt;NO3HR&lt;/code&gt; is NO&lt;sub&gt;3&lt;/sub&gt; loading kg/hr,&lt;/li&gt;&#xA;&lt;li&gt;&lt;code&gt;DISOXHR&lt;/code&gt; is O&lt;sub&gt;2&lt;/sub&gt; loading kg/hr,&lt;/li&gt;&#xA;&lt;li&gt;etc...   &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;But interestingly enough there is no NaCl loading variable!&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Am I able to customize a new variable explicitly NaCl, or will I have to use &lt;code&gt;CMTl1HR&lt;/code&gt; which is a heavy metal loading kg/hr?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was also thinking I could customize a soil type with high salinity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To you hydrologists out there: what are my options?&lt;/p&gt;&#xA;" OwnerUserId="2743" LastEditorUserId="5594" LastEditDate="2016-12-02T12:19:26.630" LastActivityDate="2016-12-02T12:19:26.630" Title="Using sodium chloride load as a point source pollutant variable in SWAT model?" Tags="|hydrology|soil|water|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4636" PostTypeId="1" AcceptedAnswerId="15181" CreationDate="2015-04-01T02:07:06.157" Score="8" ViewCount="473" Body="&lt;p&gt;Inspired by: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4589/how-does-antarctica-stay-frozen&quot;&gt;How does Antarctica stay frozen?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the Earth was in a fixed solstice state - northern winter and southern summer (e.g. the axis obliquity rotated with the Earth's orbit), what  would the equilibrium temperature be at each pole? Assume daily cycle and convection and so on operate as usual, just that it's permanent midnight in the Arctic, and permanent midday in the Antarctic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bonus questions: Would the equilibrium temperatures be significantly different if it was northern summer and southern winter (e.g. would land masses and orography have much effect, relative to the solar imbalance)?&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2018-09-27T04:25:38.457" Title="What would the equilibrium temperature be at the poles in a world without seasonality?" Tags="|hypothetical|poles|axial-obliquity|seasons|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4638" PostTypeId="2" ParentId="845" CreationDate="2015-04-01T11:01:37.177" Score="7" Body="&lt;p&gt;The previous answers contain important facts, but neglect recent discoveries. As tobias47n9e says, the increase in observed output over time is an observational effect. As kaberett explains, if you're talking about megayear timescales, Large Igneous Provinces will have a large impact on the timeseries. However, LIP and all continental eruptions (~1km^3 / year) are dwarfed by midocean ridge seafloor eruptions (~3km^3 / year).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Volcanologists have made major progress towards answering your question (are production rates trending? periodic?) over the last few years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We've learned that:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Melting icecaps causes an increase volcanic output, from this paper:&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Schmidt, Peter, et al. &quot;Effects of present‐day deglaciation in Iceland on mantle melt production rates.&quot; Journal of Geophysical Research: Solid Earth 118.7 (2013): 3366-3379.&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;Lowering sea level causes an increase midocean ridge volcanic output, from these papers:&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Tolstoy, Maya. &quot;Mid‐ocean ridge eruptions as a climate valve.&quot; Geophysical Research Letters (2015).&lt;/li&gt;&#xA;&lt;li&gt;Crowley, John W., et al. &quot;Glacial cycles drive variations in the production of oceanic crust.&quot; Science 347.6227 (2015): 1237-1240.&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The authors attributed these effects to decompression melting. If you remove a weight from above a magma chamber, the pressure in the chamber is reduced, and the melting temperature is lowered, causing an increase in the amount of melt available for eruption. (Personally, I suspect that it's not really decompression melting causing the change in eruption rate but actually just fractures opening and closing.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Tolstoy paper claims that if you look at seafloor topography, you see bumps where more lava erupted and piled up higher. Further, it says those bumps correlate with the 100,000 year Milankovitch global climate cycle. So, orbital eccentricity --&gt; sea level --&gt; midocean ridge eruption rate --&gt; seafloor topography. This is a brand new idea and needs much more testing. (Personally, I find the topography thing hard to believe because that topography is probably more fault-controlled than eruption-rate-controlled.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tolstoy even claims that low tide causes eruptions! She uses a Schuster test to say that the majority of seafloor eruptions occur during neap tide. However, we don't observe seafloor eruptions very often, so she is making this claim using only 9 data points.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's currently unknown whether these unloading / loading effects are important at subduction zones or LIP.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You've asked a difficult question which volcanologists have been attempting to understand for decades and will continue to work on for the foreseeable future. In summary, my answer is that cutting-edge research suggests that global eruption rate fluctuates in response to climate via changes in the masses pushing down on magma reservoirs.&lt;/p&gt;&#xA;" OwnerUserId="63" LastEditorUserId="63" LastEditDate="2015-04-01T17:21:48.170" LastActivityDate="2015-04-01T17:21:48.170" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4639" PostTypeId="2" ParentId="629" CreationDate="2015-04-02T00:33:31.380" Score="2" Body="&lt;p&gt;Hurricanes are tropical cyclones (TC) and these storms form in the ocean over warm waters when the sea surface temperature (SST) is above 27C or 28C. The higher the SST the greater the probability that a TC will form and the greater the probability that once formed the TC will intensify. These relationships provide the theoretical basis for the idea that rising temperatures will increase the frequency and intensity of TC events within what is known as the intertropical convergence zone. In fact, there is some empirical evidence that since the industrial revolution, there has been a long term positive trend in these events worldwide. James Elsner's study of Atlantic hurricanes and Prakash Singh's study of TC in the Indian Ocean are two examples. I did a similar study but looked only at what is known as the &quot;pause&quot; period in climate change which runs from 1998 to 2015 as of this writing and the data show that in the &lt;em&gt;pause&lt;/em&gt; period the long term upward trend in TC frequency and intensity may also have paused. My paper along with the data and complete citations to the works mentioned may be downloaded from SSRN. &#xA;&lt;a href=&quot;http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2586947&quot; rel=&quot;nofollow&quot;&gt;http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2586947&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2748" LastEditorUserId="2470" LastEditDate="2015-04-02T01:35:20.533" LastActivityDate="2015-04-02T01:35:20.533" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4640" PostTypeId="1" AcceptedAnswerId="4662" CreationDate="2015-04-02T02:17:45.037" Score="3" ViewCount="1289" Body="&lt;p&gt;A là this &lt;a href=&quot;http://www.slate.com/articles/technology/future_tense/2014/05/_10_percent_of_california_s_water_goes_to_almond_farming.html&quot; rel=&quot;nofollow&quot;&gt;Slate article&lt;/a&gt;: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;1 gallon of water is required to grow a single almond &lt;/li&gt;&#xA;&lt;li&gt;220 gallons to grow a large avocado&lt;/li&gt;&#xA;&lt;li&gt;5,000 gallons to grow 1 lb of beef&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;None of these things weighs anywhere near their water weight. So what happened to the water -- was it recycled to ecosystem?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondary question: because of the severe drought, California has imposed restrictions on water usage by agriculture. I'm wondering if most of this water ends up as ground water or if it vaporizes up into the atmosphere and blows with the winds... or there's no telling really where it goes?&lt;/p&gt;&#xA;" OwnerUserId="2750" LastActivityDate="2015-04-07T04:05:07.207" Title="What is the life-cycle of agricultural water used to grow crops/animals?" Tags="|meteorology|water|earth-system|water-vapour|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4641" PostTypeId="2" ParentId="4591" CreationDate="2015-04-02T03:48:35.323" Score="4" Body="&lt;p&gt;&lt;strong&gt;To clarify:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your question is valid, although if you are referring to Dr. von Frese's words as paraphrased in this article, you may be conflating a potential &quot;breakup initiation&quot; with something like the &quot;creation of a geologically weak area prone to rifting under extensional stress&quot;. I believe the thought that such a crater could have caused the beginnings of the rifting process was not entertained by Dr. von Frese himself. Instead, according to the article you cited, von Frese explains that Antarctica and Australia began rifting roughly 100 million years ago, and rifting just so happened to occur very near the proposed impact site. From the article:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The rift cuts directly through the crater, so the impact may have helped the rift to form, von Frese said.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It's a little unclear, but I think von Frese is making the connection here that a crater of that size could have potentially created weak planes in the crust near the impact site, which would have directed extensional stress relief to a localized region, thus centralizing a rift locally. This is a plausible conclusion, but as far as I can tell, no evidence other than proximity has been found to support it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;To answer:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The existence of the crater has not been verified, and more recent research &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/JB084iB10p05681/abstract&quot; rel=&quot;nofollow&quot;&gt;casts doubt&lt;/a&gt; about the validity of claims that the Wilkes Land structure is in fact an impact crater.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, the date for the final breakup of Gondwana is fairly well established, and enough research has been conducted to construct &lt;a href=&quot;http://www.academia.edu/1037331/The_breakup_history_of_Gondwana_and_its_impact_on_pre-Cenozoic_floristic_provincialism&quot; rel=&quot;nofollow&quot;&gt;extensive historical summaries&lt;/a&gt; of the time period. As stated by von Frese, most geologists put the start of rifting in the Wilkes Land region at about 100 million years ago, in the Cretaceous period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we allow the assumption that the crater is indeed caused by a bolide impact, most studies suggest an impact date near the time of the Permian-Triassic boundary, a period known for its multiple mass-extinctions, around 250 million years ago. That would leave roughly 70 million years between impact and Gondwana's very earliest rifting (~180 mya), which is a relatively significant amount of time by tectonic standards. As stated in the above reference, the current most accepted &quot;method&quot; of Gondwanan rifting is via mantle plumes forcing the continents apart from below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Based solely on these two pieces of evidence, I'd feel relatively confident in putting forth that the breakup of Gondwana was not caused by a bolide impact. If the Wilkes Land structure is ever drilled, and shocked quartz or other impact indicators are found in the samples, I would want to revisit this answer to investigate what I'll call &quot;Dr. von Frese's Planes of Weakness&quot; claim more closely.&lt;/p&gt;&#xA;" OwnerUserId="2749" LastEditorUserId="2749" LastEditDate="2015-04-02T14:03:27.453" LastActivityDate="2015-04-02T14:03:27.453" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4642" PostTypeId="1" AcceptedAnswerId="4643" CreationDate="2015-04-02T09:38:39.863" Score="26" ViewCount="2885" Body="&lt;p&gt;I have been doing some research on the issue of phosphogypsum pollution.  Phosphogypsum is a waste by-product formed with the &amp;quot;wet process&amp;quot; method of extraction of phosphoric acid out of phosphate rock, which uses sulfuric acid and water to break it:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\ce{Ca10(PO4)6F2 + 10H2SO4 + 20H2O -&amp;gt; 10CaSO4.2H2O + 6H3PO4 + 2HF}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Returning the phosphoric acid and gypsum (calcium sulphate, or CaSO4). The problem here is that the &lt;strong&gt;uranium in the phosphate rock produces 226Ra (among other radionuclides) during its decay,&lt;/strong&gt; and since 226Ra is an &amp;quot;Alkalin Earth Metal&amp;quot; (it's on the 2nd column of the periodic table), it can form radium sulphate and mimic calcium, leading to radioactive gypsum.&lt;/p&gt;&#xA;&lt;p&gt;The point here is, &lt;em&gt;&lt;strong&gt;why is the phosphate rock enrichened in uranium&lt;/strong&gt;&lt;/em&gt; that can produce radium? Is there a trend for phosphate and uranium to accumulate together, and if so, what is the geochemical reason??&lt;/p&gt;&#xA;&lt;p&gt;I have already found out that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Sedimentary rock phosphates contain much higher concentrations of&#xA;potentially hazardous elements (As, Cd, Cr,Pb, Se and U)than&#xA;igneous rock phosphates. &lt;a href=&quot;http://d-nb.info/996740074/34&quot; rel=&quot;noreferrer&quot;&gt;(1)&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Phosphate rock varies considerably in content of U, Ra, and Th, depending&#xA;on the geographical area from which it was mined. &lt;a href=&quot;http://www.scopenvironment.org/downloadpubs/scope54/6mortvedt.htm&quot; rel=&quot;noreferrer&quot;&gt;(2)&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;1 - Mamdoh Sattouf, Identifying the Origin of Rock Phosphates and Phosphorous Fertilisers Using Isotope Ratio Techniques and Heavy Metal  Patterns.&lt;/p&gt;&#xA;&lt;p&gt;2 - John J. Mortvedt and James D. Beaton, Heavy Metal And Radionuclide Contaminants In Phosphate Fertilizers.&lt;/p&gt;&#xA;&lt;p&gt;Thank you in advance for your help!!&lt;/p&gt;&#xA;" OwnerUserId="2751" LastEditorUserId="2470" LastEditDate="2021-08-28T14:48:26.523" LastActivityDate="2023-02-10T21:49:33.293" Title="Why does phosphate rock contain uranium?" Tags="|geology|geochemistry|radioactivity|uranium|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4643" PostTypeId="2" ParentId="4642" CreationDate="2015-04-02T12:35:33.723" Score="20" Body="&lt;p&gt;To understand why sedimentary phosphate rocks (hereafter referred to as &lt;strong&gt;phosphorites&lt;/strong&gt;) have elevated uranium contents we first need to understand what are they made of and why do they form in the first place.&lt;/p&gt;&#xA;&lt;p&gt;Phosphorites are rocks that are made of apatite, a mineral with the formula &lt;span class=&quot;math-container&quot;&gt;$\ce{Ca5(PO4)3(F,Cl,OH)}$&lt;/span&gt;. This mineral (especially the OH variant) is one of the main constituents of skeletons of living organisms. The hard mineralised part of your teeth and bones are made of apatite, for instance.&lt;/p&gt;&#xA;&lt;p&gt;Skeletons of dead marine animals (e.g. fish) are deposited on the ocean floor as apatite. The source of apatite need not be biogenic: it can also be sourced from igneous or hydrothermal activity occurring on the ocean floor, or derived as clastic material from the continents. The end result, is the deposition of apatite as phosphorites.&lt;/p&gt;&#xA;&lt;p&gt;An important property of apatite is that it can accommodate some uranium. The mechanism is not yet completely understood, but it's most likely the incorporation of &lt;span class=&quot;math-container&quot;&gt;$\ce{U^4+}$&lt;/span&gt; in the mineral structure of apatite, replacing calcium. Now here's the interesting part - uranium in sea water is mostly present as &lt;span class=&quot;math-container&quot;&gt;$\ce{U^6+}$&lt;/span&gt; (in the form of the uranyl ion). The uranyl ion is more soluble than &lt;span class=&quot;math-container&quot;&gt;$\ce{U^4+}$&lt;/span&gt;, so uranium mostly remains as utanyl ion in solution in the sea water. But, as we mentioned earlier, apatite deposits form by the decay of dead marine animals. This accumulation of decaying organic material reduces the &lt;span class=&quot;math-container&quot;&gt;$\ce{U^6+}$&lt;/span&gt; to &lt;span class=&quot;math-container&quot;&gt;$\ce{U^4+}$&lt;/span&gt;, facilitating its incorporation into the apatite structure.&lt;/p&gt;&#xA;&lt;p&gt;That's only one side of the coin. Apparently &lt;span class=&quot;math-container&quot;&gt;$\ce{U^6+}$&lt;/span&gt; can also be adsorbed on apatite grains. This is even used in some cases to stop uranium contamination from migrating through soil - by adding apatite to it in order to immobilise it.&lt;/p&gt;&#xA;&lt;p&gt;Whatever the exact process (or combination of processes) that make uranium such a good friend of apatite, the end result is that apatite (and rocks containing it) is enriched in uranium relative to its environment.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="20607" LastEditDate="2023-02-10T21:49:33.293" LastActivityDate="2023-02-10T21:49:33.293" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="4644" PostTypeId="2" ParentId="4640" CreationDate="2015-04-02T19:13:30.323" Score="4" Body="&lt;p&gt;The water cycle isn't geology, but it's important to pedology, which is an earth science. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Agricultural water can be converted (by &lt;em&gt;photosynthesis&lt;/em&gt;) directly into simple carbohydrates that we eat; or converted into carbs and then used as structure or energy that keeps the organism alive and growing, but isn't the mass we finally eat; or used to build more complicated parts of the organism (fats, protein) that we finally eat; or transferred to the atmosphere (mostly) because none of these biological processes are leak-proof; or transferred to the atmosphere or groundwater because we don't get all the water to the plant roots exactly when the plants can use it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we eat meat, there's all of the above in making the plants the animal eats, and then even greater inefficiency in turning water-in-plants into animal flesh, and the greater structure and energy costs to keep the animal alive and growing. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The crops listed are not simple carbs, or even self-fertilizing legumes. It takes a lot of tree to make an almond or an avocado. It takes a lot of water to grow the alfalfa and grains that we fatten cows on. There's also water in the processing, the cold chain, often in generating the power that makes nitrogen fertilizer or moves food from California (CA) to the markets.  CA's main ag land is dry and warm and often windy in the summer, so it can lose water really quickly (either through the plants or from flood or overhead irrigation, and even a little bit through mulched soil). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know about all of CA (it's a big place with a lot of different climates), but at least some -- the west side of the Central Valley -- is having soil trouble because they rarely get enough irrigation or rain to flush salts and excess fertilizer out of the root zone, so they at least aren't sending excess water to groundwater. One could check stream gauges to guess whether excess water is making it into &lt;em&gt;surface&lt;/em&gt; water -- my guess, not. &lt;/p&gt;&#xA;" OwnerUserId="2639" LastEditorUserId="2639" LastEditDate="2015-04-03T17:47:02.813" LastActivityDate="2015-04-03T17:47:02.813" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4645" PostTypeId="1" CreationDate="2015-04-03T03:27:43.217" Score="5" ViewCount="623" Body="&lt;p&gt;The question is simple: what is the earliest tropical cyclone (hurricane or typhoon) described in the historical record? &lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="192" LastEditDate="2015-04-03T13:41:29.317" LastActivityDate="2015-04-03T14:11:55.480" Title="What is the earliest tropical cyclone in record?" Tags="|earth-history|tropical-cyclone|history-of-science|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4646" PostTypeId="1" CreationDate="2015-04-03T13:06:24.747" Score="13" ViewCount="338" Body="&lt;p&gt;If I add acetic acid to limestone, I can get calcium acetate crystals to grow but if I add acetic acid to dolomite, supposedly I can grow aragonite which is a form of calcium carbonate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why would I get crystals of an acetate in one instance and a carbonate in the other? And, what happens to the acetate ion and the magnesium when forming aragonite?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that aragonite can form instead of calcite because of something called &quot;magnesium poisoning&quot; but I still do not understand how any carbonate is formed when dolomite is immersed in acetic acid. &lt;/p&gt;&#xA;" OwnerUserId="2754" LastEditorUserId="28050" LastEditDate="2018-05-18T00:13:02.597" LastActivityDate="2018-06-20T11:45:18.917" Title="Why does aragonite form in one case and an acetate in another?" Tags="|geochemistry|mineralogy|crystallography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="4647" PostTypeId="2" ParentId="4645" CreationDate="2015-04-03T14:11:55.480" Score="6" Body="&lt;p&gt;Japanese legend claims that typhoons twice save Japan from attempted invasions by Kublai Khan, once in 1274 and seven years later 1281. These divine winds (&quot;kamikaze&quot;) are mixed in Japanese mysticism and are perhaps apocryphal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Chinese were meticulous record keepers and recorded disasters of all kinds. Liu et al. scoured written Chinese history for records of typhoons. T earliest unequivocal report of a typhoon they found was in the “Official History” of the Song Dynasty:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In the tenth lunar month of the eighth year of the reign of Kai Bao [i.e., November AD 975], the city of Guangzhou was struck by a jufeng [typhoon]. Two zhang [a traditional Chinese measurement unit that equals about three meters] of rain fell within a day and night. The sea rose. Some boats were blown away and lost.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The Mayans were also meticulous record keepers and their homeland, the Yucatan, suffers a high rate of hurricane landfalls. There are two problems, however. One is that the Spanish conquistadors and the priests they brought with them were extremely meticulous about hunting down and destroying Mesoamerican writings. The other issue is that those writings were inextricably interwoven with the bizarre religion of the Mayans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Popol Vuh, written by the Dominican priest Francisco Ximénez around the turn of the 18th century, records some aspects of Mayan mythologies. The translations are a bit challenging. The Popol Vuh describes the ball court (which was very important to the Mayans), describes many of the Mayan deities, describes the Mayan creation story. One translation of this creation story follows.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Heart of Sky arrived here with Sovereign and Quetzal Serpent in the darkness, in the night. He spoke with Sovereign and Quetzal Serpent. They talked together then. They thought and they pondered. They reached an accord, bringing together their words and their thoughts. Then they gave birth, heartening one another. Beneath the light, they gave birth to humanity. Then they arranged for the germination and creation of the trees and the bushes, the germination of all life and creation, in the darkness and in the night, by Heart of Sky, who is called Huracan. First is Thunderbolt Huracan, second is Youngest Thunderbolt, and third is Sudden Thunderbolt. These three together are Heart of Sky.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Note the name of the Heart of Sky, Hurucan. Others translate that name as Juracán, yet others, Hurricane. That Mayan god may well be the source of the word &quot;hurricane&quot;. Then again, that god might have been given that name based on an already existing word. Similar sounding words were used throughout Mesoamaerica and the Caribbean to describe what we now call hurricanes, and also to describe the god of the sky.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Heart of Sky was a blood-thirsty god (many of the Mayan gods were blood-thirsty.) Two surviving Mayan stelae (carved stone monuments) depict a destructive event dated on one of the stelae as having occurred on June 3, 544 that depict whirling winds and pools of blood. That might well have been a hurricane. Then again, it might have been the ascension of a powerful king who aligned himself with Heart of Sky.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Stephen Houston, &quot;Hurricane!&quot;, &lt;a href=&quot;http://www.mesoweb.com/articles/houston/hurricane.pdf&quot;&gt;http://www.mesoweb.com/articles/houston/hurricane.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kam‐biu Liu, Caiming Shen, and Kin‐sheun Louie. &quot;A 1,000‐Year History of Typhoon Landfalls in Guangdong, Southern China, Reconstructed from Chinese Historical Documentary Records.&quot; Annals of the Association of American Geographers 91.3 (2001): 453-464.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-04-03T14:11:55.480" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4648" PostTypeId="1" AcceptedAnswerId="4649" CreationDate="2015-04-03T15:47:17.243" Score="8" ViewCount="4850" Body="&lt;p&gt;I'm confused by what exactly a CDL file is and what its purpose is. &lt;a href=&quot;http://www.unidata.ucar.edu/software/netcdf/netcdf/CDL-Syntax.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Unidata&lt;/a&gt; specifies the syntax of such a CDL file in its &lt;a href=&quot;http://www.unidata.ucar.edu/software/netcdf/netcdf/CDL-Syntax.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;netCDF documentation&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Questions:&lt;br&gt;&#xA;Are CDL files designed to be opened by a simple text editor like Notepad or gedit? Or should I use some other tool to open it?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is its purpose and how is it used?&lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorUserId="5594" LastEditDate="2017-08-23T11:17:25.807" LastActivityDate="2017-08-23T11:17:25.807" Title="CDL File Questions" Tags="|data-formats|software|netcdf|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4649" PostTypeId="2" ParentId="4648" CreationDate="2015-04-03T16:02:41.183" Score="10" Body="&lt;p&gt;A CDL file is basically a text output from a netcdf file.  If you want to know the contents of a netcdf file but don't have the time (or ability) to use programs built to read/write netcdf, you can use the simple text output of &quot;ncdump&quot; and then read/write it with a basic text editor.  You can also use &quot;ncgen&quot; to regenerate a netcdf file based on the new CDL file.  I've used this process to make simple changes to netcdf files, and it works very quickly compared to generating a netcdf file using programming methods.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;http://www.atmos.washington.edu/ive/ive_help/writing_netCDF_files.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.atmos.washington.edu/ive/ive_help/writing_netCDF_files.html&lt;/a&gt; , quoted below:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A CDL (network Common data form Description Language) file is an ASCII descripton of the binary data in a netCDF file that is designed to be easily read by humans. CDL files can be generated from netCDF files via the `ncdump', command. For example,&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;ncdump -c sample.nc&#xA;  generates the file `sample.cdl' that contains the file name, the dimensions, the specification of the variables, any attributes and the data for any &quot;coordinate variables.&quot; A CDL file of this type is shown below. Note that the double slash indicates a comment in the CDL file.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;netcdf implicit_grid{&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;dimensions:&#xA;  lon = 101;&#xA;  lat = 101;&#xA;  level = 5;&#xA;  time = UNLIMITED ; //(7 currently)&#xA;  variables:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;float A(time,level,lat,lon);&#xA;  A:units = &quot;meters/second&quot;;&#xA;  float level(level);&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;level:units = &quot;millibars&quot;;&#xA;  float time(time);&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;time:units = &quot;hours&quot;;&#xA;  //global attributes:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;:x_min = -180.f;&#xA;  :x_max = 180.f;&#xA;  :x_units = &quot;degrees_east&quot;;&#xA;  :x_label = &quot;longitude&quot;;&#xA;  :y_min = -90.f;&#xA;  :y_max = 90.f;&#xA;  :y_units = &quot;degrees_north&quot;;&#xA;  :y_label = &quot;latitude&quot;;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;:z_label = &quot;level&quot;;&#xA;  :t_label = &quot;time&quot;;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;data:&#xA;  level = 1000, 850, 700, 500, 300 ;&#xA;  time = 0, 2, 4, 6, 8, 10, 12 ;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The command &lt;code&gt;ncgen' is the inverse of&lt;/code&gt;ncdump'; it converts an ASCII CDL file to a binary netCDF file. For example&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;ncgen -o sample.nc sample.cdl&#xA;  converts the CDL file &lt;code&gt;sample.cdl' to the netCDF file&lt;/code&gt;sample.nc'. The easiest way to create a netCDF file is to (1) write all the header data (the name, dimensions, variable and attribute specifications, and the values of any coordinate variables) to a CDL file, (2) convert the CDL file to a netCDF file using ncgen, and (3) continue writing the main data arrays to this netCDF file.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2015-04-03T19:02:20.723" LastActivityDate="2015-04-03T19:02:20.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4650" PostTypeId="2" ParentId="4589" CreationDate="2015-04-03T19:54:42.247" Score="7" Body="&lt;p&gt;First of all, the Earth does not receive heat from the Sun, it receives visible light that is absorbed by the surface of the Earth and then heat is re-radiated back into the atmosphere.  If the surface is ice/snow, most of the light from the sun is reflected back to space.  Sunlight will sublimate a little bit of the ice, but it is normally replenished at a faster rate than it is lost.      &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ice endures through the summer in Antarctica, even as the air warms up.  This is in contrast to the ice at the Arctic pole that completely melts every summer.  This is for 2 reasons:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Unlike the arctic, the ice in Antarctica is on a continental shelf, so there is no water beneath it to help melt the ice.  &lt;/li&gt;&#xA;&lt;li&gt;Antarctica is the highest continent on Earth, with an average elevation of 8,200ft.  At that elevation and within the polar region, ice can persist indefinitely because the average atmospheric temperature is very cold.  At high elevations, there is little atmosphere to trap any heat radiated by the Earth, which is why the air is so cold at high elevations.  &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;For these reasons, ice near the coast of Antarctica typically is lost much faster than ice in the mountains.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2015-04-03T19:54:42.247" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4651" PostTypeId="1" CreationDate="2015-04-04T00:31:05.150" Score="6" ViewCount="178" Body="&lt;p&gt;An offshoot from the question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4589/how-does-antarctica-stay-frozen&quot;&gt;how does Antarctica stay frozen?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do the Anatarctic circumpolar vortex and circumpolar ocean current play a role in keeping Antarctica frozen? &lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-06-15T19:49:17.667" Title="The Role of the Antarctic Circumpolar Vortex &amp; Ocean Current in Keeping Antarctica Frozen" Tags="|climate|antarctic|ice|thermodynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4652" PostTypeId="1" CreationDate="2015-04-04T01:38:24.400" Score="8" ViewCount="722" Body="&lt;p&gt;This question is an object of fascination of mine. There are a few different angles to take to it. My favorite is blasting the moon out of existence while its moving away from Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would happen if Earth's moon was removed?&lt;/p&gt;&#xA;" OwnerUserId="2758" LastEditorUserId="192" LastEditDate="2015-04-05T15:47:53.187" LastActivityDate="2015-08-07T21:10:20.630" Title="What would happen if we removed Earth's moon?" Tags="|planetary-science|hypothetical|moon|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4654" PostTypeId="1" CreationDate="2015-04-04T15:40:49.877" Score="9" ViewCount="174" Body="&lt;p&gt;I want to show that the higher the Sun's altitude, the higher the solar irradiation through the atmosphere, through &lt;em&gt;simple experiments&lt;/em&gt;. However, I don't have the instrument that measures irradiation. Is there a good approach?&lt;/p&gt;&#xA;" OwnerUserId="2761" LastEditorUserId="192" LastEditDate="2015-04-05T15:45:32.803" LastActivityDate="2016-02-03T08:57:04.397" Title="Dependence of solar irradiation through the atmosphere on Sun's altitude" Tags="|meteorology|geophysics|solar-terrestrial-physics|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4655" PostTypeId="2" ParentId="4654" CreationDate="2015-04-04T20:46:16.590" Score="1" Body="&lt;p&gt;I believe you could use pyranometer data at various elevations to get a non-spectral measurement of the total irradiance received at the Earth's surface.  From here: &lt;a href=&quot;http://en.wikipedia.org/wiki/Pyranometer&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/Pyranometer&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A pyranometer is a type of actinometer used to measure broadband solar irradiance on a planar surface and is a sensor that is designed to measure the solar radiation flux density (W/m2) from a field of view of 180 degrees. &#xA;  Pyranometers are frequently used in meteorology, climatology, solar energy studies and building physics. They can be seen in many meteorological stations - typically installed horizontally and next to solar panels - typically mounted with the sensor surface in the plane of the panel.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;If you want something more accurate, a pyrheliometer or radiometer is used.  From &lt;a href=&quot;http://www.esrl.noaa.gov/gmd/grad/starmeas.html&quot; rel=&quot;nofollow&quot;&gt;http://www.esrl.noaa.gov/gmd/grad/starmeas.html&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;Direct solar irradiance&lt;/em&gt; is the solar radiation that passes directly though the atmosphere from the sun without being scattered or absorbed by the atmosphere. Typically it is measured on a surface that is kept normal to the direction of the center of the sun's disk. That surface is held normal to the sun's position by a solar tracker. Pyrheliometers are most commonly used to measure total direct solar irradiance. The most accurate measurements of this quantity are obtained from absolute cavity radiometers which serve as calibration standards and are being increasingly used operationally.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastActivityDate="2015-04-04T20:46:16.590" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4656" PostTypeId="1" AcceptedAnswerId="4657" CreationDate="2015-04-05T05:09:02.017" Score="5" ViewCount="2201" Body="&lt;p&gt;I need US monthly climate data for the years 1992-2012. It would be great to get down to a county level, but by state would be just fine. Every site that I go to inevitably kicks me to the &lt;a href=&quot;http://www.ncdc.noaa.gov/cdo-web/search?datasetid=GHCNDMS&quot; rel=&quot;noreferrer&quot;&gt;NCDC&lt;/a&gt;, but I cannot make sense of their data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example: the .csv sample data for &lt;a href=&quot;http://www.ncdc.noaa.gov/cdo-web/datasets&quot; rel=&quot;noreferrer&quot;&gt; GHCN Monthly Summaries &lt;/a&gt; lists EMXT (extreme maximum temperature) for each month of 2010 in Petersburg, ND. July had an EMXT of 317. I've been through the documentation, but I can't figure out what that number is supposed to mean. I know it wasn't 317F or C in ND at any point. Did they add all the temps up? Was it around 10C every day of July 2010? But why would you do that? The .PDF data looks like actual temperatures, but I need a lot of data: .CSV is ideal; .PDF is really not useable for the amount of data I am going to manipulate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What am I missing? Or is there another way to get this data? &lt;/p&gt;&#xA;" OwnerUserId="2543" LastEditorUserId="2543" LastEditDate="2015-04-05T06:02:23.747" LastActivityDate="2015-04-05T08:54:10.787" Title="Deciphering NCDC data" Tags="|climate|temperature|precipitation|open-data|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4657" PostTypeId="2" ParentId="4656" CreationDate="2015-04-05T08:54:10.787" Score="4" Body="&lt;p&gt;The &lt;a href=&quot;http://www1.ncdc.noaa.gov/pub/data/cdo/documentation/GHCNDMS_documentation.pdf&quot; rel=&quot;nofollow&quot;&gt;documentation linked from the datasets page&lt;/a&gt; states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Air Temperature (all units in Fahrenheit on PDF monthly form and &lt;strong&gt;tenths of degrees Celsius&lt;/strong&gt; on CSV or text)&lt;br&gt;&#xA;  EMNT - Extreme minimum temperature *&lt;br&gt;&#xA;  EMXT - Extreme maximum temperature *  &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://www1.ncdc.noaa.gov/pub/data/cdo/samples/GHCNDMS_sample_ascii.dat&quot; rel=&quot;nofollow&quot;&gt;Petersburg data&lt;/a&gt; looks plausible under this interpretation (EMXT −3.9°C to 33.9°C over the year).&lt;/p&gt;&#xA;" OwnerUserId="94" LastActivityDate="2015-04-05T08:54:10.787" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="4658" PostTypeId="2" ParentId="845" CreationDate="2015-04-05T09:53:16.743" Score="2" Body="&lt;p&gt;I would just like to quickly emphasize the forward-mindedness of lunar and additional celestial mechanics when looking at fluctuations in global eruption rates.  Since it isn't just the oceans which ripple in response to the passing over of other bodies, it may be subsumed that there will be some flux in accordance with gravitational tides.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this case, &lt;em&gt;orbital resonance&lt;/em&gt; is likely to emerge as an important consideration for the study of volcanic activity on earth - we already know that volcanic activity elsewhere in the solar system can be demonstrated by this as friction from tidal flexing.&lt;/p&gt;&#xA;" OwnerUserId="2764" LastActivityDate="2015-04-05T09:53:16.743" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4661" PostTypeId="1" CreationDate="2015-04-07T03:05:09.903" Score="10" ViewCount="123" Body="&lt;p&gt;Wind above the planetary boundary layer (PBL) tends to be fairly smooth and constant over short periods of time. Below the planetary boundary layer, the smoothness is broken by eddies caused by friction with the land surface. Below the canopy, wind is presumably even more turbulent, and much slower on average. I'm interested to know how the over-all effect of those eddies changes wind direction within the canopy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How much do eddies between the PBL and the ground disperse wind direction? Is wind direction below the canopy still correlated with the wind direction above the PBL? And does wind speed follow a similar pattern?&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2015-04-08T23:04:21.863" Title="Does within-canopy wind direction correlate with wind above the planetary bounday layer?" Tags="|wind|land-surface|turbulence|planetary-boundary-layer|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4662" PostTypeId="2" ParentId="4640" CreationDate="2015-04-07T04:05:07.207" Score="4" Body="&lt;p&gt;The linked article talks about irrigated agriculture so I'll focus on that, but things are generally the same for rain-fed agriculture, except you have less control on the water application and there is no loss in getting the rain to where it hits the ground (yes some rain evaporates as it falls but we measure rain at the ground).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For irrigation water, though some is lost between the water intake and the field. We don't usually consider evaporation along rivers but when you take water out of a river some evaporates as it flows through canals to where it is used. Some water is also lost through leakage since many canals are just excavated in the soil. Relatively few irrigation water systems are piped but that is one way to make water use more efficient. Lining canals with cement or plastic can help prevent leakage (a number of channels are lined with plastic near where I live but animals like koalas can get trapped as they try to cross).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The next place water is lost is in evaporation from the irrigation spray or ground surface. That is usually considered in calculating water use for growing crops. Hot dry weather will increase the loss and for some soils a dry surface can inhibit infiltration of the water. Some water usually ends up back in the streams or wetlands from surface runoff or from returns to the canal systems.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another loss is water that flows through the root zone before plants can use it. That flow can be important in keeping salts from building up to the point where the crop yield declines or plants can't survive. On the other hand it can leach metals from the soil down into the groundwater.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you probably know, plants take up water from their roots and use it in photosynthesis to grow. They also respire at night when there is no photosynthesis. That water is the major part of the water use by the plants - very little is left in the biomass. There are some ways to breed plants or engineer your crop (like pruning trees) to make the plant water use more efficient in terms of how much product yield you get, but these are somewhat limited. And, of course, water is used by weeds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bottom line, most water in agriculture ends up as evapotranspiration (evaporation from the surface plus transpiration from plants). Some is lost to the groundwater or returned to surface water from the irrigation systems.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are further inefficiencies in meat and dairy production. Some water is lost in metabolism, urine, feces, etc. And animals have to eat a lot of food to put on weight.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2015-04-07T04:05:07.207" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4663" PostTypeId="1" CreationDate="2015-04-07T05:36:04.643" Score="13" ViewCount="675" Body="&lt;p&gt;&lt;strong&gt;The Premise&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth rotates on its own axis, which is tilted by about 23 degrees. I am imagining a situation where such an axial tilt does not exist. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From general reading, it appears the largest impact of removing an axial tilt would be on seasonal change, in the sense that there wouldn't be any changes whatsoever. Every latitudinal belt would have its own set season all year round, with some minimal changes depending on the earth's distance from the sun in its usual orbit (ranging basically from 91.4 million miles in January compared to 91.5 million miles in July - which is less than 1%).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The Question&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would be the implication on rain cycles if the Earth had no Axial Tilt? It appears to me that rain carrying clouds move to the dictates of wind blowing to an area with a different air pressure. If our planet had no axial tilt, the Equator would get extremely hot all year round, causing water to evaporate and move north or south towards cooler areas - at least that's my understanding. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What parts of earth would receive the most rainfall if such a change were to occur?&lt;/p&gt;&#xA;" OwnerUserId="2770" LastEditorUserId="111" LastEditDate="2016-08-29T15:56:40.493" LastActivityDate="2016-08-29T15:56:40.493" Title="Climate on an Earth without an Axial Tilt" Tags="|climate|earth-rotation|axial-obliquity|" AnswerCount="1" CommentCount="13" ContentLicense="CC BY-SA 3.0" />
  <row Id="4664" PostTypeId="1" CreationDate="2015-04-07T09:55:17.807" Score="9" ViewCount="250" Body="&lt;p&gt;I would appreciate some help in identifying these clouds:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/5L9Qz.jpg&quot; alt=&quot;http://i.imgur.com/rwhWWii.jpg&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This was taken on a commercial plane flying between Hong Kong and Japan on the 31st of March around 2pm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried looking up cloud types but was not too sure. This sort of had two different looks - one being a flat kind of sea, and the other being the smaller, noisier clouds popping up from underneath.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks very much.&lt;/p&gt;&#xA;" OwnerUserId="2771" LastEditorUserId="6298" LastEditDate="2022-02-06T17:30:44.880" LastActivityDate="2022-02-06T17:30:44.880" Title="What type of clouds are these?" Tags="|atmosphere|clouds|identification-request|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4665" PostTypeId="1" CreationDate="2015-04-08T01:58:44.683" Score="18" ViewCount="7717" Body="&lt;p&gt;Both roughness length $z_0$ and zero plane displacement $d$ seemed to be defined as the height above the ground at which wind speed theoretically becomes zero. But wind speed is also supposed to go to zero at $d+z_0$. What is the difference between the two, and how should they actually be defined?&lt;/p&gt;&#xA;" OwnerUserId="2774" LastEditorUserId="192" LastEditDate="2015-04-08T17:56:55.190" LastActivityDate="2021-09-22T12:04:20.037" Title="What is the difference between roughness length and zero plane displacement?" Tags="|atmosphere|wind|planetary-boundary-layer|" AnswerCount="2" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4666" PostTypeId="2" ParentId="4665" CreationDate="2015-04-08T18:30:46.990" Score="12" Body="&lt;p&gt;First some definitions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$z_0$: &lt;em&gt;Roughness length&lt;/em&gt; is defined as the height at which the mean velocity is zero due to substrate roughness. Real walls/ground are not smooth and often have varying degrees of roughness, this parameter (which is determined empirically) accounts for that effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$d$: &lt;em&gt;Zero Plane displacement&lt;/em&gt; is defined as the height at which the mean velocity is zero due to large obstacles such as buildings/canopy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The two parameters are not the same because they describe the effects of two fundamentally different processes. $d$ can be anywhere from $6$ to $20$ times larger than $z_0$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The basis for most turbulence modeling is the eddy viscosity model:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$-\overline{u'w'} = \nu_t \frac{\partial U}{\partial z}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\nu_t$ is the eddy viscosity. Employing some scaling arguments with basis on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mixing_length_model&quot; rel=&quot;noreferrer&quot;&gt;Prandtl mixing length model&lt;/a&gt; and integrating one arrives at the &lt;a href=&quot;https://en.wikipedia.org/wiki/Law_of_the_wall&quot; rel=&quot;noreferrer&quot;&gt;logarithmic law of the wall&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$${U} = \frac{u^*}{\kappa} \ln\, \frac{z}{z_0}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your equation is &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$${U} = \frac{u^*}{\kappa} \ln\, \frac{z-d}{z_0}$$&#xA;which is the law of the wall with $d = 0$ because it applies to flat plates. It is easy to see then, that by subtracting $d$ from $z$ the effect is to reduce $U$ at that height, which makes sense because large obstacles remove energy from the mean flow and slow it down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that if there are no large obstacles then $d \approx 0$, but $z_0$ is still larger than zero.&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2015-04-08T23:02:48.160" LastActivityDate="2015-04-08T23:02:48.160" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4667" PostTypeId="2" ParentId="4661" CreationDate="2015-04-08T23:04:21.863" Score="1" Body="&lt;p&gt;Turbulence is a property of the flow, not a physical characteristic of the fluid. Turbulent flows in nature are evolving due to external influences and at present time there are very few evolving turbulent flows which are well understood. The boundary conditions, such as distribution of canopy, geomorphology, all play a crucial role in determining the turbulent dynamics. All turbulent flows are different but they have similar intrinsic dynamics and through statistical means one can relate the properties of the mean flow to the turbulent dynamics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&quot;Big whorls have little whorls&#xA;That feed on their velocity;&#xA;And little whorls have lesser whorls;&#xA;And so on to viscosity.&quot;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Lewis_F._Richardson&quot; rel=&quot;nofollow&quot;&gt;Lewis Fry Richardson&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Turbulence is a multiscale phenomenon where small eddies in turbulence have very short timescales. This alone tends to make them statistically independent from the mean flow. Therefore, smallscale motion depends only on the rate at which it is supplied energy from the larger scales, and the rate at which kinetic energy is dissipated into heat. The two rates of change are assumed the same so that the net rate of change is small comparing to the rate of dissipation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the basis for Kolmogorov's universal equilibrium theory. It basically says that the rate of energy supply to smallscale eddies is equal to the the dissipation rate:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$U^3/L \sim \epsilon \, .$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, the dissipative effects of viscosity can be estimated from the large scale dynamics, which are effectively inviscid. Inertial effects cause a transfer of energy from small to large wavenumber space by vortex stretching.The mean flow kinetic energy transforms into turbulent energy in the form of large eddies which cascade down to smaller eddies and so on, the remaining fluctuations are ultimately dissipated by viscous damping. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Turbulent velocity fluctuations generate large momentum fluxes between different regions of the flow which is a process analogous to stress (Reynolds stresses). The Reynolds stress is what quantifies the contribution of the turbulent motion to the mean flow. Because the momentum transfer mechanism resembles molecular diffusion, turbulent moment exchange is modeled with an eddy viscosity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;All this discussion is still inside the boundary layer itself. Outside the boundary layer is the mean wind which supplies the necessary shear for turbulence inside the boundary layer. Although this wind is not affected by the turbulent fluctuations within the boundary layer, it is the reason why they exist. &lt;/p&gt;&#xA;" OwnerUserId="200" LastActivityDate="2015-04-08T23:04:21.863" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4668" PostTypeId="1" AcceptedAnswerId="4701" CreationDate="2015-04-09T04:00:18.767" Score="6" ViewCount="256" Body="&lt;p&gt;It is believed that during the Carboniferous period, fungi and bacteria lacked the biochemical means to decompose lignin and release $\ce{CO_2}$ back to the atmosphere. So dying trees carbon became trapped in coal deposits. But whence came all carbon allowing these plants grow?&lt;/p&gt;&#xA;" OwnerUserId="1061" LastEditorUserId="1061" LastEditDate="2015-04-13T13:13:45.763" LastActivityDate="2015-04-17T10:23:49.393" Title="Sources of $\ce{CO_2}$ during Carboniferous period" Tags="|paleoclimatology|carbon-cycle|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4669" PostTypeId="1" CreationDate="2015-04-09T08:27:59.620" Score="4" ViewCount="145" Body="&lt;p&gt;I have to classify the climate zones for &lt;a href=&quot;http://en.wikipedia.org/wiki/Western_Ghats&quot; rel=&quot;nofollow&quot;&gt;Western Ghats&lt;/a&gt; using the Holdridge method. The classifiers are temperature, rainfall, elevation. Elevation is constant. But for temperature and rainfall how many years of data should I take? Should I take mean annual temperature just for the recent year or for a certain period?&lt;/p&gt;&#xA;" OwnerUserId="2738" LastEditorUserId="28050" LastEditDate="2015-04-13T11:58:15.730" LastActivityDate="2015-04-13T11:58:15.730" Title="Climate zone classification using the Holdridge method" Tags="|climate|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4670" PostTypeId="1" CreationDate="2015-04-09T15:20:04.093" Score="5" ViewCount="101" Body="&lt;p&gt;NOAA has solar radiation data for 1991-2010 &lt;a href=&quot;http://www.ncdc.noaa.gov/data-access/land-based-station-data/land-based-datasets/solar-radiation&quot; rel=&quot;noreferrer&quot;&gt;http://www.ncdc.noaa.gov/data-access/land-based-station-data/land-based-datasets/solar-radiation&lt;/a&gt; But I need data for Nov 1 2012-present! Is this data available?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Will I have to generate it myself? I have the software to do it, it is just a time/processor consuming task.&lt;/p&gt;&#xA;" OwnerUserId="2743" LastActivityDate="2015-04-11T00:23:28.640" Title="Where can I find solar radiation data for specific land areas?" Tags="|meteorology|solar-terrestrial-physics|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4671" PostTypeId="1" AcceptedAnswerId="4673" CreationDate="2015-04-09T15:48:53.413" Score="19" ViewCount="1855" Body="&lt;p&gt;Is it a coincidence? the first is determined by the amount of water on the Earth and the second comes from evolution of tectonic plates. Still, oceans seem to fill exactly the oceanic crust.&lt;/p&gt;&#xA;" OwnerUserId="2775" LastEditorUserId="6298" LastEditorDisplayName="user12525" LastEditDate="2021-10-04T21:32:35.623" LastActivityDate="2021-10-04T21:32:35.623" Title="Why does sea level correspond to boundary between oceanic and continental crust?" Tags="|geology|geophysics|plate-tectonics|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="4673" PostTypeId="2" ParentId="4671" CreationDate="2015-04-10T16:14:22.293" Score="23" Body="&lt;p&gt;&lt;strong&gt;Sea-level only sort-of corresponds to the oceanic–continental crust boundary.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In depth, they don't correspond at all:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/H1E95.jpg&quot; alt=&quot;Passive margin plate boundary&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's the same story at an active margin: the plate boundary at a subduction zone is buried several kilometres beneath a wedge of sediment:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/hC34M.gif&quot; alt=&quot;Subducting margin&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What about spatially? As you can see from &lt;a href=&quot;http://en.wikipedia.org/wiki/Oceanic_crust#/media/File:2008_age_of_oceans_plates.jpg&quot; rel=&quot;noreferrer&quot;&gt;this map&lt;/a&gt;, they don't correspond all that well spatially either: they are commonly 100s of kilometres apart, sometimes more.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/rPA0s.jpg&quot; alt=&quot;Age of oceanic crust; NOAA&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The difference, shaded grey in the map, is the continental shelf. It is sometimes emergent (e.g. at the end of the Permian, or during ice ages, when global sea-levels are low). It is sometimes, as now, flooded. The vertical change of ca. 100–250 m means a lateral change of 100s of km, because the shelf is almost flat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;OK, enough nit-picking, roughly speaking, why are the oceans on oceanic crust?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Continental_crust&quot; rel=&quot;noreferrer&quot;&gt;Continental crust&lt;/a&gt; is relatively thick and low density (ca. 2700 kg/m$^3$), compared to oceanic crust (25–70 km and ca. 2900 kg/m$^3$). So it 'floats' higher on the thin, dense mantle (7–10 km and ca. 3300 kg/m$^3$). When a new rift forms, it creates a depression and space for new oceanic-style crust. This is happening right now in the &lt;a href=&quot;http://en.wikipedia.org/wiki/Gulf_of_California_Rift_Zone&quot; rel=&quot;noreferrer&quot;&gt;Gulf of California&lt;/a&gt;, the &lt;a href=&quot;http://en.wikipedia.org/wiki/Baikal_Rift_Zone&quot; rel=&quot;noreferrer&quot;&gt;Baikal Rift Zone&lt;/a&gt;, and in the extensive &lt;a href=&quot;http://en.wikipedia.org/wiki/East_African_Rift&quot; rel=&quot;noreferrer&quot;&gt;East African Rift&lt;/a&gt; system. All of these places have large lakes and/or are extensively below sea-level. It's a divergent 'tear' in the continental crust, so intuitively we might expect a depression. As it fills with thin oceanic crust, the depression is maintained and eventually fills with ocean water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Why is ocean crust so thin?&lt;/strong&gt; I don't have a lot of expertise here, but I think it's determined by the relative rates of melting and cooling, and the heat balance at the ridge and subduction zones. There's a nice answer to this question &lt;a href=&quot;http://www.reddit.com/r/askscience/comments/117r5o/why_is_the_earths_crust_thinner_under_the_oceans/&quot; rel=&quot;noreferrer&quot;&gt;on Reddit&lt;/a&gt;, complete with links. As insinuated in that thread, the thermo- and chemo-dynamics of the spreading centres and subduction zones are intimately related to the presence of the ocean, so together they make a complex system (indeed, the entire planet is a complex system), as @stali points out in his comments and answer.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2015-04-11T10:41:18.523" LastActivityDate="2015-04-11T10:41:18.523" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="4674" PostTypeId="2" ParentId="4671" CreationDate="2015-04-10T22:06:27.053" Score="0" Body="&lt;p&gt;First of all, yes the sea level corresponds rather well to the boundary between oceanic and continental crusts. The mean width of the continental shelf is mere 80 km, much smaller than the mean width of contents or oceans. And if you drop it by a few meters the number will decrease.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think the reason for the correspondence is that over long periods of time water and oceanic crust are part of the same system so think of them together and not separately. Its just that at earth's surface they separate from each other and some water is transported to continents via precipitation. Some people think water and plate tectonics, as we know it, go hand in hand. It would also explain why we don't observe plate tectonics or significant amount of water on other nearby planets.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;@borilla What I mean is that the water we have in oceans was originally in the mantle rocks. E.g., see &lt;a href=&quot;http://www.pri.org/stories/2015-01-10/how-earth-made-its-own-water-out-rocks&quot; rel=&quot;nofollow&quot;&gt;http://www.pri.org/stories/2015-01-10/how-earth-made-its-own-water-out-rocks&lt;/a&gt;. So basically when the earth formed, buoyant continental crust formed/separated relatively quickly and its volume has been relatively constant over time (i.e., not too different from today, only rearranged differently) but there was little liquid water. It came slowly out of mantle rocks through mid ocean ridge volcanism and so you can think of water and oceanic crust as being part of the same system. Mantle rocks still hold more water than that in all the oceans put together.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2015-04-11T13:12:37.393" LastActivityDate="2015-04-11T13:12:37.393" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4675" PostTypeId="2" ParentId="4670" CreationDate="2015-04-11T00:23:28.640" Score="5" Body="&lt;p&gt;The Measurement and Instrumentation Data Center (MIDC, &lt;a href=&quot;http://www.nrel.gov/midc/&quot;&gt;http://www.nrel.gov/midc/&lt;/a&gt;) provides Irradiance and other Meteorological Data from several stations. Have you also check in: &lt;a href=&quot;https://mapsbeta.nrel.gov/nsrdb-data-viewer/&quot;&gt;https://mapsbeta.nrel.gov/nsrdb-data-viewer/&lt;/a&gt;? Some of the data maybe until the end of 2012 used to be in &lt;a href=&quot;http://rredc.nrel.gov/solar/old_data/nsrdb/&quot;&gt;http://rredc.nrel.gov/solar/old_data/nsrdb/&lt;/a&gt;. Good luck!&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-04-11T00:23:28.640" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4678" PostTypeId="1" AcceptedAnswerId="4680" CreationDate="2015-04-13T17:58:08.473" Score="7" ViewCount="317" Body="&lt;p&gt;The &lt;a href=&quot;http://en.wikipedia.org/wiki/Sequence_stratigraphy#Sequence_boundaries&quot;&gt;Wikipedia page on sequence stratigraphy&lt;/a&gt; states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Sandstone bodies associated with incised valleys are good hydrocarbon&#xA;  reservoirs.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Can anyone elaborate on this statement and the reason behind it?&lt;/p&gt;&#xA;" OwnerUserId="594" LastEditorUserId="28050" LastEditDate="2015-04-13T18:08:29.730" LastActivityDate="2015-04-13T18:50:41.777" Title="Incised valleys and hydrocarbon potential" Tags="|geophysics|sedimentology|stratigraphy|petroleum|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4679" PostTypeId="1" CreationDate="2015-04-13T18:46:03.097" Score="16" ViewCount="361" Body="&lt;p&gt;Iceland has been cited as the location of a hot-spot overlying a mantle plume (similar to that of the Hawaii chain in the Pacific), though for some time this model has been challenged (see &lt;a href=&quot;http://www.mantleplumes.org/&quot;&gt;Gillian Foulger's mantle plumes site&lt;/a&gt;, especially &lt;a href=&quot;http://www.mantleplumes.org/Iceland2.html&quot;&gt;Lundin &amp;amp; Doré's article&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How does &lt;a href=&quot;http://phys.org/news/2015-04-fragment-continental-crust-southeast-iceland.html&quot;&gt;the recent announcement&lt;/a&gt; by &lt;a href=&quot;http://dx.doi.org/10.1073/pnas.1423099112&quot;&gt;Torsvik et al. (2015)&lt;/a&gt; — that south east Iceland is underlain by continental crust — affect this debate?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Torsvik, TH, et al. (2015), PNAS online 30 March 2015. DOI: &lt;a href=&quot;http://dx.doi.org/10.1073/pnas.1423099112&quot;&gt;10.1073/pnas.1423099112&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="140" LastEditorDisplayName="user12525" LastEditDate="2019-04-30T13:19:43.737" LastActivityDate="2019-04-30T13:19:43.737" Title="Is Iceland an example of a hot-spot overlying a mantle plume?" Tags="|geology|geophysics|plate-tectonics|mantle-plumes|hotspot|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4680" PostTypeId="2" ParentId="4678" CreationDate="2015-04-13T18:50:41.777" Score="10" Body="&lt;p&gt;&lt;strong&gt;Sandstone bodies in incised valleys &lt;em&gt;can be&lt;/em&gt; good hydrocarbon reservoirs.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Incised valleys form on the coastal plain and/or continental shelf during a fall in relative sea-level by a combination of fluvial and marine processes (e.g. fluvial erosion, headward erosion). Here's some coastal plain incision by the &lt;a href=&quot;https://www.google.ca/maps/place/New+Zealand/@-44.2282751,171.3792034,9038m/data=!3m1!1e3!4m2!3m1!1s0x6d2c200e17779687:0xb1d618e2756a4733&quot; rel=&quot;nofollow noreferrer&quot;&gt;Orari River&lt;/a&gt; in New Zealand — look at those sand bars!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/cGW3V.jpg&quot; alt=&quot;Orari River, New Zealand&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With the caveat that incised valleys can be filled with mud (non-reservoir) too, there are a few reasons why lots of hydrocarbon fields have been discovered in incised valleys:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Incision spatially focuses sediment delivery to the shelf-edge and slope. So if coarser sediment (needed for porosity preservation and therefore a reservoir) is stranded on the shelf, there'll be more of it the incision.&lt;/li&gt;&#xA;&lt;li&gt;Sediment only stays where there is &lt;a href=&quot;http://wiki.aapg.org/Sequence_stratigraphy#Accommodation&quot; rel=&quot;nofollow noreferrer&quot;&gt;'accommodation'&lt;/a&gt;. A big hole that wasn't there before (like a new valley) is accommodation.&lt;/li&gt;&#xA;&lt;li&gt;The valley acts as a container, so channels tend to have a high ratio of thickness to width.&lt;/li&gt;&#xA;&lt;li&gt;For these reasons, valleys sometimes fill with multi-storey sand/mud successions. Lots of reservoirs!&lt;/li&gt;&#xA;&lt;li&gt;After the sea-level fall comes sea-level rise, or &lt;a href=&quot;https://en.wikipedia.org/wiki/Marine_transgression&quot; rel=&quot;nofollow noreferrer&quot;&gt;'transgression'&lt;/a&gt;. Everything is flooded, and you're back to a marine environment. There's mud everywhere and so now you have a top seal.&lt;/li&gt;&#xA;&lt;li&gt;It's relatively easy to connect a valley to a marine &lt;a href=&quot;https://en.wikipedia.org/wiki/Source_rock&quot; rel=&quot;nofollow noreferrer&quot;&gt;source rock&lt;/a&gt;, either directly updip via porosity, or via faults or other conductors.&lt;/li&gt;&#xA;&lt;li&gt;Unlike &lt;a href=&quot;http://www.sepmstrata.org/Terminology.aspx?id=basin-floor%20fan&quot; rel=&quot;nofollow noreferrer&quot;&gt;basin-floor fans&lt;/a&gt;, which can also be good reservoirs, incised valleys are on the shelf and might still be beneath the modern shelf. This means there are many more options for drilling wells targeting them, and it's much cheaper and easier.&lt;/li&gt;&#xA;&lt;li&gt;Compared to unincised systems, incised valleys are relatively easy to spot in well logs and even on seismic. So they are conspicuous, and easily diagnosed. &lt;/li&gt;&#xA;&lt;li&gt;Since the start of the incised valley craze in the 1990s, incised valleys have been deliberately targeted, so there's probably some sample bias: lots of wells means lots of discoveries!&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The last little gem is that, even if there's no luck exploring on the shelf, incised valleys might mean that coarse sediment has been delivered to the basin floor, opening up a promising play there too.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-04-13T18:50:41.777" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4681" PostTypeId="1" CreationDate="2015-04-13T21:02:01.317" Score="14" ViewCount="2462" Body="&lt;p&gt;Is there a way to use accelerometer data to characterize earthquake intensity, e.g., on Richter scale?&lt;/p&gt;&#xA;" OwnerUserId="2785" LastEditorUserId="28050" LastEditDate="2015-04-14T21:24:38.450" LastActivityDate="2015-04-17T22:59:45.003" Title="Characterizing earthquakes using accelerometer data" Tags="|earthquakes|measurements|instrumentation|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4682" PostTypeId="2" ParentId="4679" CreationDate="2015-04-13T23:17:58.270" Score="8" Body="&lt;p&gt;Yes, Iceland is an example of a hotspot overlying a plume. The plume has been imaged seismically, e.g., see the Science paper (Figure 3) by Montelli et al. (2004). It is available at &lt;a href=&quot;http://www.sciencemag.org/content/303/5656/338&quot;&gt;http://www.sciencemag.org/content/303/5656/338&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The 2015 paper you referred doesn't dispute that claim. All is says is that &quot;The plume split off a sliver of continent from Greenland in the Early Eocene. This sliver is now located beneath southeast Iceland where it locally contaminates some of the plume-derived magmas&quot;.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastActivityDate="2015-04-13T23:17:58.270" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4683" PostTypeId="2" ParentId="4681" CreationDate="2015-04-14T05:07:18.953" Score="3" Body="&lt;p&gt;It appears the issue with using accelerometers for characterizing earthquake intensity is their lack of sensitivity, as you can read from the &lt;a href=&quot;http://www.livescience.com/30656-detect-earthquake-with-home-computer.html&quot; rel=&quot;nofollow&quot;&gt;live science&lt;/a&gt; website. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But that does not mean that accelerometers can't provide useful information about earthquakes, particularly larger quakes. Stanford University has established the &lt;a href=&quot;http://qcn.stanford.edu/&quot; rel=&quot;nofollow&quot;&gt;Quake-Catcher Network&lt;/a&gt; to provide it with earthquake information from accelerometers in people laptops and other devices. More information about this can be found at their other &lt;a href=&quot;http://qcn.stanford.edu/sensor/&quot; rel=&quot;nofollow&quot;&gt;web page&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-04-14T05:07:18.953" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4684" PostTypeId="1" CreationDate="2015-04-14T10:56:06.813" Score="8" ViewCount="3577" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Robert_E._Horton&quot;&gt;Robert E. Horton&lt;/a&gt; coined these four laws:  the law of stream numbers, the law of stream lengths, the limits of infiltration capacity, and the runoff-detention-storage relation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are they specifically? Googling only yielded me paywalled articles and test questions. A good answer will state the laws and provide a brief explanation of what they mean. I want to understand what they tell me about river systems and what comparisons between different rivers I can make based on them. I'm not looking for an in-depth examination, or for an excourse on the purely mathematical side.&lt;/p&gt;&#xA;" OwnerUserId="117" LastEditorUserId="117" LastEditDate="2015-04-15T08:14:45.863" LastActivityDate="2015-04-15T08:14:45.863" Title="What are Horton's laws?" Tags="|hydrology|rivers|runoff|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4685" PostTypeId="2" ParentId="4684" CreationDate="2015-04-14T14:42:51.500" Score="4" Body="&lt;p&gt;&lt;a href=&quot;http://www.physicalgeography.net/fundamentals/10ab.html&quot; rel=&quot;nofollow&quot;&gt;Physicalgeography.net&lt;/a&gt; and the &lt;a href=&quot;http://www.engr.colostate.edu/~ramirez/ce_old/classes/cive322-Ramirez/CE322_Web/Example_Horton_html.htm&quot; rel=&quot;nofollow&quot;&gt;Colorado State basic hydraulic page&lt;/a&gt; have a good explanation of Horton's Laws.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first thing that needs to be done in analysing a drainage basin is to classify the stream segments in a basin according to Strahler's method. For each stream order tabulate:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the number of segments&lt;/li&gt;&#xA;&lt;li&gt;the average length of the segments&lt;/li&gt;&#xA;&lt;li&gt;the average area of drainage for the segments&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;According to Physicalgeography.net the bifurcation ratio is the ratio between the number of stream segments in one order and the number of stream segments in the next order.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Horton saw that the bifurcation ratio was always around 3, this he called the Law of Stream Numbers. Apparently a bifurcation ratio of 3 also applies to plant roots, branching of woody plants, veining in leaves and the human circulatory system. I get the impression that without knowing about it, Horton was laying some ground work for fractal mathematics that came to prominence in the 1980s, with the work of Benoit Mandelbrot.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With the Law of Stream Lengths, the average length of stream for each order is calculated, then cumulate lengths found before length ratios between segment orders can be calculated. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.engr.colostate.edu/~ramirez/ce_old/classes/cive322-Ramirez/CE322_Web/Example_Horton_html.htm&quot; rel=&quot;nofollow&quot;&gt;Colorado State basic hydraulic page&lt;/a&gt; has a more mathematical approach to explaining Horton's Laws, but it's very good. It gives a worked example of how to determine the all the coefficients.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additional information is also on this &lt;a href=&quot;http://www.stevekluge.com/geoscience/apg/labs/horton%27s%20laws.pdf&quot; rel=&quot;nofollow&quot;&gt;site&lt;/a&gt; as well.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-04-14T14:42:51.500" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4686" PostTypeId="1" AcceptedAnswerId="4691" CreationDate="2015-04-14T19:35:51.200" Score="11" ViewCount="1885" Body="&lt;p&gt;Recycling metal and some plastics makes complete sense to me. Why bury something in a landfill that you'll have to find and dig up more of later. What I don't get is why we recycle paper products, especially those created with plant matter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My understanding is that the fossil fuels we use for energy were generated during the Carboniferous period by burying carbon rich plant matter in anoxic swamps. If we are causing climate change by reversing this effect, dumping tons of carbon back into the carbon cycle... why recycle paper, or other products created, necessarily, by pulling carbon from the atmosphere? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wouldn't a more beneficial method of disposing of such waste be to find a method of isolating them from the effects of weathering and keeping the carbon they contain locked up as long as possible?&lt;/p&gt;&#xA;" OwnerUserId="2786" LastActivityDate="2019-09-20T14:24:45.410" Title="Why do we recycle paper?" Tags="|climate-change|carbon-cycle|" AnswerCount="4" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4687" PostTypeId="2" ParentId="4681" CreationDate="2015-04-14T21:13:17.230" Score="8" Body="&lt;p&gt;&lt;strong&gt;Yes, you can measure seismic energy with accelerometers. Most people do.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are three ways to measure seismic energy: by displacement $x$, velocity $\dot{x}$, or acceleration $\ddot{x}$. Loose-spring devices like &lt;a href=&quot;http://www.agilegeoscience.com/blog/2011/7/15/geophysical-stamps-3-geophone.html&quot; rel=&quot;nofollow&quot;&gt;geophones&lt;/a&gt; measure velocity; stiff-spring devices like &lt;a href=&quot;http://en.wikipedia.org/wiki/Microelectromechanical_systems&quot; rel=&quot;nofollow&quot;&gt;MEMS&lt;/a&gt; and &lt;a href=&quot;http://en.wikipedia.org/wiki/Gravimeter&quot; rel=&quot;nofollow&quot;&gt;relative gravimeters&lt;/a&gt; measure acceleration: they are accelerometers. Those used in seismology and exploration geophysics are very precise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I wrote about the various instruments used to measure seismic energy in &lt;a href=&quot;http://www.agilegeoscience.com/blog/2011/7/15/geophysical-stamps-3-geophone.html&quot; rel=&quot;nofollow&quot;&gt;a blog post&lt;/a&gt; a while back. An excerpt about seismometers:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Seismometers [are] precision instruments not used in exploration&#xA;  seismology because they are usually quite bulky and require careful&#xA;  set-up and calibration. [Most modern models] are accelerometers, much&#xA;  like relative gravimeters, measuring ground acceleration from the&#xA;  force on a proof mass. Seismometers can detect frequencies in a very&#xA;  broad band, on the order of 0.001 Hz to 500 Hz: that's 19 octaves!&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Short story: When digital seismic receivers arrived on the scene in Calgary in the early 2000s, there was a lot of skepticism. We spent a lot of time comparing them to traditional geophones. The conclusion: they were about the same. &lt;a href=&quot;http://www.crewes.org/ResearchLinks/GraduateTheses/2008/Hons-MSc-2008.pdf&quot; rel=&quot;nofollow&quot;&gt;Here's one comparison&lt;/a&gt; by Michael Hons at CREWES, and &lt;a href=&quot;http://www.searchanddiscovery.com/pdfz/abstracts/pdf/2013/90170cspg/abstracts/ndx_hons.pdf.html&quot; rel=&quot;nofollow&quot;&gt;here's another&lt;/a&gt;; &lt;a href=&quot;http://www.sercel.com/products/Lists/ProductPublication/Sercel-digital-geophone.pdf&quot; rel=&quot;nofollow&quot;&gt;here's yet another&lt;/a&gt; from one of the big manufacturers, Sercel (now CGG). Finally, &lt;a href=&quot;http://www.iris.edu/hq/instrumentation_meeting/files/pdfs/MEMS_Seismology.pdf&quot; rel=&quot;nofollow&quot;&gt;here's a presentation&lt;/a&gt; more oriented around earthquake seismology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Okay, but I was talking about the accelerometers in iPhones!&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oh, sorry. As @Fred points out in his answer, consumer-grade MEMS accelerometers (as you might find in a phone or latop) may not have the sensitivity or calibration that a researcher would want, but one might compensate somewhat for this with multiple measurements, e.g. an array of devices. In other words: quantity, not quality. (This is perfectly legit: we do it in exploration seismics too.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://bayen.eecs.berkeley.edu/sites/default/files/journals/15WCEE_iShake.pdf&quot; rel=&quot;nofollow&quot;&gt;Dashti et al. (2013)&lt;/a&gt; in &lt;em&gt;Earthquake Spectra Journal&lt;/em&gt; found you could get useful measurements (e.g. for emergency response) from networks of phones with a few tricks:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The more measurements the better.&lt;/li&gt;&#xA;&lt;li&gt;Horizontal orientation is best.&lt;/li&gt;&#xA;&lt;li&gt;Prefer high-friction phone covers.&lt;/li&gt;&#xA;&lt;li&gt;Don't expect to get great data for small quakes.&lt;/li&gt;&#xA;&lt;li&gt;Treat small groups of phones as arrays.&lt;/li&gt;&#xA;&lt;li&gt;Don't use data for phones that fell off a table!&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="20" LastEditDate="2015-04-17T22:59:45.003" LastActivityDate="2015-04-17T22:59:45.003" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4688" PostTypeId="2" ParentId="4686" CreationDate="2015-04-15T00:45:23.040" Score="4" Body="&lt;p&gt;The main source of &quot;fresh&quot; paper is trees. Forests, either natural or plantations, have to be cut down to satisfy our need for paper. It is well established that forests are a major sink for carbon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The more paper that get recycled the fewer the forests that need to be clear felled for paper production and the less disruption to the Earth's carbon sinks and the so called &quot;lungs of the Earth&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recycled paper get used in a variety of products, cardboard boxes being one of the main ones, but also toilet paper, tissues, disposable nappies/dipers, fast food packaging and packaging fillers when items are bought on-line and delivered in cardboard boxes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One way to reduce our impact on the planet in terms of forest destruction, land degradation, pollution, atmospheric carbon and its affects on global warming would be to reduce our usage of paper so that even fewer forest are clear felled. Recycling paper is helping the planet by reducing the impact on our forests.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-04-15T00:45:23.040" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4689" PostTypeId="2" ParentId="4686" CreationDate="2015-04-15T02:28:00.900" Score="5" Body="&lt;p&gt;This question (and my answer) borders on opinion but is a good example of the interface between the science and policy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Forests and tree plantations are a sink for carbon but that sink is a one-off credit because trees die and decay, cycling the carbon dioxide back into the atmosphere. So growing new trees will tie up additional carbon dioxide from the atmosphere but maintaining existing mature forests will be carbon neutral. Harvesting existing forests without reforestation can increase atmospheric carbon dioxide if the wood is burned or allowed to decay.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the paper and wood products are sequestered from decay or if the decay is significantly slower than the existing cycle, then atmospheric carbon sequestration will increase if the forest is allowed to regrow and the forest sink is maintained. So the original supposition is basically correct provided it doesn't lead to increased deforestation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are some additional considerations that would have to be addressed by a life-cycle analysis of the paper industry. Does it take more fossil fuel to make paper from harvested trees or from collecting, sorting, transporting, and reprocessing paper? That could tip the balance one way or another. In addition, the non-carbon value of the forests should be considered. Will the forestry cause excessive environmental harm through habitat shifts, road building, increased stream sedimentation during harvest, etc?&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2015-04-15T02:28:00.900" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4690" PostTypeId="2" ParentId="4668" CreationDate="2015-04-15T07:19:35.487" Score="1" Body="&lt;p&gt;In a nutshell, if we assume that the earth's atmosphere (and water) came largely from comets, then it's simply about asking, what are comets made of - $\ce{H2O}$, $\ce{CO2}$, $\ce{CH4}$, $\ce{NH3}$, other ices, dust.    $\ce{CO2}$ is abundant, it arrived pretty much the same way the water did.    The earth has trapped/absorbed most of it's $\ce{CO2}$.   There used to be a lot more of it in the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="87" LastEditDate="2015-04-17T08:52:24.320" LastActivityDate="2015-04-17T08:52:24.320" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4691" PostTypeId="2" ParentId="4686" CreationDate="2015-04-15T08:55:12.277" Score="8" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;My understanding is that the fossil fuels we use for energy were&#xA;  generated during the Carboniferous period by burying carbon rich plant&#xA;  matter in anoxic swamps. If we are causing climate change by reversing&#xA;  this effect, dumping tons of carbon back into the carbon cycle... why&#xA;  recycle paper, or other products created, necessarily, by pulling&#xA;  carbon from the atmosphere?&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Wouldn't a more beneficial method of disposing of such waste be to&#xA;  find a method of isolating them from the effects of weathering and&#xA;  keeping the carbon they contain locked up as long as possible?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I think part of your question has gone unanswered, so I'll give it a shot.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;I'm not sure there's enough anoxic bodies of water/swamps available for that kind of project, and 2, it's not easy to bury something in a swamp, there would be issues of transportation (many million tons of recycled paper), so it would be fairly work intensive.   It's not easy burying millions of tons under a swamp and paper floats - so, there's no guarantee it would be long term anyway.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Let's look at how much paper is used.   Roughly 3.3 billion cubic meters of trees are harvested every year, over half of that goes into fuel for cooking and heating.    17% goes into making paper (presumably that would go up if we stop recycling, so lets say 20%-25%.   And wood is about 50% carbon  (sources all in the link below)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.tappi.org/paperu/all_about_paper/faq.htm&quot; rel=&quot;nofollow&quot;&gt;http://www.tappi.org/paperu/all_about_paper/faq.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, theoretical anoxic stored used paper &amp;amp; cardboard.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3.3 billion cubic meters (harvested per year) × 20%-25% (paper/cardboard share) × 50% (carbon content) × let's say density of 900 kg per cubic meter (because the estimate is size not mass).   If you returned all the paper and cardboard into anoxic storage, roughly 0.3 - 0.37 billion tons of carbon (not CO&lt;sub&gt;2&lt;/sub&gt;, just carbon) could be stored per year.    Mankind's production, about 8 billion tons of carbon.  (I'm calculating carbon not CO&lt;sub&gt;2&lt;/sub&gt; which is about 30 billion tons per year).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, the simple truth of it is that we use a lot more oil than we do paper.  Even if every last scrap of used paper and every bit of used cardboard were all anoxicly stored, that would reduce our carbon footprint maybe 3%-4%.   If you add to that, every bit of discarded wood - what then?   5%.  6, maybe 7%, and such actions would be both energy intensive and require increased tree cutting mentioned in the other answers, so there would be a fair measure of diminished returns.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A friend, who I used to debate this subject with often, had a similar idea - you want to fight greenhouse gas, he'd say, just build more things out of wood.  Wood stores carbon, which it does.  He was right, but we can't grow and harvest enough wood to make a real dent in our carbon footprint.   Besides, when wood is harvested, and turned into furniture or a house or whatever else, energy goes into that.   I'm not sure how much is even saved from the footprint by building more things from wood.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's a good question but I think, ultimately, not practical.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.paperimpact.org/how-much-wood-is-harvested-each-year-world-wide-and-what-is-it-used-for-1941.html&quot; rel=&quot;nofollow&quot;&gt;http://www.paperimpact.org/how-much-wood-is-harvested-each-year-world-wide-and-what-is-it-used-for-1941.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="20" LastEditDate="2015-04-17T22:53:51.137" LastActivityDate="2015-04-17T22:53:51.137" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="4692" PostTypeId="2" ParentId="4686" CreationDate="2015-04-15T17:24:05.133" Score="16" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Wouldn't a more beneficial method of disposing of such waste be to find a method of isolating them from the effects of weathering and keeping the carbon they contain locked up as long as possible?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You are ignoring a number of factors here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good deal of energy, much of it non-renewable, is needed to turn trees into paper. The trees need to be cut down (requires petroleum), transported to the saw mill (more petroleum), sawed and chipped (requires electricity), transported again (more petroleum). Once it gets to the paper mill, it needs to be pulped (requires petrochemicals, which need to be transported (requires petroleum)). The pulping process also consumes a good deal of electricity, as does the process of turning pulp into paper.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bottom line: Paper has a positive carbon footprint.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you send that paper to a landfill after using it, the carbon in that paper will be released to the environment, and in fairly short order. On the other hand, recycling paper bypasses a number of the steps involved in turning trees into paper. Turning paper into pulp is easy. Recycling paper reduces paper's positive carbon footprint by a significant amount.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question specifically asks about finding a method of isolating wastes from the effects of weathering. That's not easy. Anaerobic bacteria find paper to be quite yummy. A deep ocean trench &lt;em&gt;might&lt;/em&gt; work, but it would be better to not make paper in the first place. Growing and harvesting trash trees and then sending them into the deep would be more effective. A number of early geoengineering proposals suggested doing just that. There are big problems here, mostly unintended consequences. Deep sixing trees in deep ocean trenches is no longer viewed as a viable carbon sequestration scheme.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-04-15T17:24:05.133" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4693" PostTypeId="1" CreationDate="2015-04-15T21:03:29.613" Score="6" ViewCount="419" Body="&lt;p&gt;According to Curray (1991):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Total sediment thickness beneath the [Ganges–Brahmaputra delta] southeast&#xA;  of the hingezone exceeds 16 km...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Considering a normal geothermal gradient and data for oil and gas formation, this suggests that at such the at some point we must have oil and gas reservoirs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/oX0rz.gif&quot; alt=&quot;Geothermal gradient&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What could be a possible explanation why no such discoveries have been made so far in the region?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reference: Curray, JR (1991). Geological history of the Bengal geosyncline. &lt;em&gt;J. Assoc. Explor. Geophys.&lt;/em&gt; &lt;strong&gt;12&lt;/strong&gt;, 209–219.&lt;/p&gt;&#xA;" OwnerUserId="594" LastEditorUserId="28050" LastEditDate="2015-04-16T01:21:09.717" LastActivityDate="2015-04-16T01:33:24.630" Title="Hydrocarbon potential in Ganges Brahmaputra delta" Tags="|geophysics|geology|sedimentology|petroleum|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4695" PostTypeId="2" ParentId="255" CreationDate="2015-04-15T22:45:46.540" Score="5" Body="&lt;p&gt;As mentioned, the theory is so vague that it's impossible to falsify nor support it with present methods and data. Geologists can learn something about the limitation of tomographic models in this overview: &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1111/ter.12041/full&quot; rel=&quot;nofollow&quot;&gt;Foulger et al 2013&lt;/a&gt;. Even the mantle plume model for the Emperor Chain have been challenged in some studies. One of the strongest arguments comes from &lt;a href=&quot;http://www.sciencemag.org/content/270/5238/947.short&quot; rel=&quot;nofollow&quot;&gt;Cande et al 1995&lt;/a&gt;, who shows that the tectonic movements and the locations of the sea-mount chain don't agree. (However, the study has itself been questioned.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only strong supportive argument from seismic data I could think of would be if guided waves were detected as suggested by &lt;a href=&quot;http://www.bssaonline.org/content/100/2/497.short&quot; rel=&quot;nofollow&quot;&gt;Julian and Evans 2010&lt;/a&gt;, but as far as I know (please correct me!) there is yet no study that have seen it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can't be sure that plumes don't exist, but I'm afraid that the simplified theory obscures more complex and true models about mantle dynamics. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2749" LastEditDate="2015-04-19T16:19:43.193" LastActivityDate="2015-04-19T16:19:43.193" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4696" PostTypeId="2" ParentId="4358" CreationDate="2015-04-16T00:02:41.973" Score="7" Body="&lt;p&gt;On the North Slope of Alaska, I have seen lakes that are frozen all the way to the bottom. It's a fascinating site in the spring when the lakes thaw from the top down because the ice on the bottom of the lake is glued to vegetation and sediments (see picture). Around these lakes are small, narrow rivers called &quot;beaded streams.&quot; In the winter/early spring, these streams are either dry or have running water. I don't believe (for all the reasons listed above) that there would be a completely frozen river. Any portion of a river that would be small enough with the potential to freeze completely, would likely dry out before the winter (although the ground all around the river is frozen... permafrost). And any &quot;river&quot; that became standing water, would be classified as a lake, slough, or backwater area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, a solution for you may be to check out Alexandra Falls in the Northwest Territories, Canada. The falls are pretty huge and freeze over in the wintertime!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/RpaF1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="2788" LastActivityDate="2015-04-16T00:02:41.973" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4697" PostTypeId="2" ParentId="4693" CreationDate="2015-04-16T01:33:24.630" Score="5" Body="&lt;p&gt;&lt;strong&gt;There have been a few discoveries in the Bay of Bengal.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Santos &lt;a href=&quot;http://www.energy-pedia.com/news/bangladesh/new-149166&quot;&gt;made a gas discovery&lt;/a&gt; in 2012, and depending on what you'd call part of the delta complex (all of the Bengal Fan?), there are others. One field, Sangu, saw several years of production, but &lt;a href=&quot;http://www.santos.com/our-activities/asia/bangladesh.aspx&quot;&gt;seems to be shut-in&lt;/a&gt; today. Another, Kutubdia, &lt;a href=&quot;http://www.platts.com/latest-news/natural-gas/dhaka/santos-still-seeking-kutubdia-gas-field-exploration-8767647&quot;&gt;is awaiting development&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's true though that there have not been many at all, if you compare with some other big deltas, like Niger or the Gulf of Mexico. Blakely (2010) suggested there are border disputes, which definitely slows exploration. I'm just guessing, but there may be other factors, such as regulatory issues, slow government licensing, or political pressures. Reading around, it does seem fair to say that the region has not been fully explored, and clearly there is a working hydrocarbon system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Blakeley, I (2010). Bay of Bengal. &lt;em&gt;GEO Expro&lt;/em&gt; &lt;strong&gt;7&lt;/strong&gt; (6). &lt;a href=&quot;http://www.geoexpro.com/articles/2010/06/bay-of-bengal&quot;&gt;Available online&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-04-16T01:33:24.630" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4698" PostTypeId="1" AcceptedAnswerId="4699" CreationDate="2015-04-16T06:21:52.593" Score="7" ViewCount="735" Body="&lt;p&gt;Different post-stack inversion methods such as model based, sparse spike, colored and recursive inversion methods use high cut frequency impedance logs (low frequency) and mid-frequency seismic trace in order to generate an inverted impedance model. Then why are high frequency components are not taken into account during inversion?&lt;/p&gt;&#xA;" OwnerUserId="2662" LastEditorUserId="28050" LastEditDate="2015-04-16T17:23:07.930" LastActivityDate="2015-04-16T17:23:07.930" Title="Why do most seismic inversion methods ignore high frequencies?" Tags="|geophysics|seismology|inversion|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4699" PostTypeId="2" ParentId="4698" CreationDate="2015-04-16T12:28:20.443" Score="10" Body="&lt;p&gt;&lt;strong&gt;Because those frequencies are not present in the seismic data.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's an example with some typical numbers:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Seismic sample interval: 4 ms&lt;/li&gt;&#xA;&lt;li&gt;Therefore &lt;a href=&quot;https://en.wikipedia.org/wiki/Nyquist_frequency&quot;&gt;Nyquist&lt;/a&gt; is 0.5 $\times$ 1/0.004 = 125 Hz&lt;/li&gt;&#xA;&lt;li&gt;Usually there is a filter on the recorder at 0.8 $\times$ Nyquist = 100 Hz&lt;/li&gt;&#xA;&lt;li&gt;So the seismic does not contain frequencies beyond 100 Hz&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The maximum frequency $f_\text{max}$ of the data determines its resolving power. There are &lt;a href=&quot;http://www.agilegeoscience.com/blog/2011/7/8/tuning-geology.html&quot;&gt;various ways&lt;/a&gt; to think about and calculate this; here's one formula (Kallweit &amp;amp; Wood, 1982):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\tau_\text{min} = \frac{1}{1.4\,f_\text{max}}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in our example, the thinnest resolvable bed is about 1 / (1.4 $\times$ 100) = 7.1 ms, and it will be thicker than that if there is a lot of noise or the bandwidth is not optimal (the earth attenuates high frequencies more than low ones, so this is an absolute minimum). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we assume a P-wave velocity of 2500 m/s, then 7.1 ms two-way time is about 2500 * (7.1/2) = 8.9 m (55 ft). Ordinary wireline logs have a resolution of 0.15 m or 6 in, so there's a substantial discrepancy. I call this &lt;a href=&quot;http://www.agilegeoscience.com/blog/2011/1/5/the-integration-gap.html&quot;&gt;'the integration gap'&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because the seismic contains no information about geology thinner than this 8.9 m (in this example), not only is it pointless trying to invert for it, but it would be dangerous: anything we thought we'd resolved would be erroneous. This is why it's necessary to filter the logs back to the resolution of the seismic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kallweit, R &amp;amp; L Wood (1982). The limits of resolution of zero-phase wavelets. &lt;em&gt;Geophysics&lt;/em&gt; &lt;strong&gt;47&lt;/strong&gt; (7), p 1035–1046, &lt;a href=&quot;http://dx.doi.org/10.1190/1.1441367&quot;&gt;DOI:10.1190/1.1441367&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-04-16T12:28:20.443" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4701" PostTypeId="2" ParentId="4668" CreationDate="2015-04-16T18:11:25.997" Score="3" Body="&lt;p&gt;The terrestrial vegetation makes ca. 500 PgC (i. e. $500 \times 10^{15}$ grams of Carbon) which is rather small compared to the carbon stored in the ocean of ca. 37 000 PgC, see Fig. 6.1 in Ciais et al. 2013 &lt;sup&gt;1&lt;/sup&gt;.&lt;br&gt;&#xA;Even if we assume that the fossil fuels reserves are the remainders of the Carboniferous period, they only add up to no more than ca. 2 000 PgC. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The terrestrial biosphere only makes use of a very small portion of the total available carbon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;&#xA;&lt;sup&gt;1&lt;/sup&gt; Ciais, P., C. Sabine, G. Bala, L. Bopp, V. Brovkin, J. Canadell, A. Chhabra, R. DeFries, J. Galloway, M. Heimann, C. Jones, C. Le Quéré, R.B. Myneni, S. Piao and P. Thornton, 2013. &lt;a href=&quot;http://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter06_FINAL.pdf&quot; rel=&quot;nofollow&quot;&gt;Carbon and Other Biogeochemical Cycles&lt;/a&gt;. In T. F. Stocker et al. (Eds): &lt;em&gt;Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change&lt;/em&gt;. Cambridge University Press, Cambridge, United Kingdom and New York, NY, USA. &#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="2789" LastEditorUserId="2789" LastEditDate="2015-04-17T10:23:49.393" LastActivityDate="2015-04-17T10:23:49.393" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4702" PostTypeId="2" ParentId="4651" CreationDate="2015-04-16T18:58:08.347" Score="2" Body="&lt;p&gt;The Antarctic Circumpolar Current keeps the warm waters away from the higher latitudes because Antarctica is disconnected from other land masses. This in turn amplifies the westerlies and therefore, polar front Antarctic Circumpolar Current prevent any warmer air/water to enter the high latitudes of Antarctica.[more on this: &lt;a href=&quot;http://en.wikipedia.org/wiki/Antarctic_Circumpolar_Current&quot; rel=&quot;nofollow&quot;&gt;wikipedia&lt;/a&gt;]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During the Oligoncene/Eocene boundary about 32 million years ago, the Tasman Passage opened which gave rise to the onset of Antarctic glaciation [more on this &lt;a href=&quot;http://en.wikipedia.org/wiki/Oligocene#The_Drake_Passage&quot; rel=&quot;nofollow&quot;&gt;wikipedia&lt;/a&gt;]&lt;/p&gt;&#xA;" OwnerUserId="2789" LastActivityDate="2015-04-16T18:58:08.347" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4704" PostTypeId="1" CreationDate="2015-04-17T10:49:51.623" Score="8" ViewCount="197" Body="&lt;p&gt;In an  answer to this question - &lt;a href=&quot;https://earthscience.stackexchange.com/questions/3101/what-is-the-predictability-of-el-ni%C3%B1o-la-ni%C3%B1a&quot;&gt;What is the predictability of El Ni&amp;#241;o/La Ni&amp;#241;a?&lt;/a&gt; Isopycnal Oscillation talks about a &quot;decrease in skill during the boreal spring as SST anomalies are abnormally variable&quot;. Today a private weather forecasting company in India made a prediction of the Indian Summer Monsoon claiming that the Indian Summer Monsoon will be unaffected by an impending El Niño in boreal summer(news report available on the net). &#xA;Given the point made earlier about the so called &quot;spring predictability barrier&quot; my question is &lt;strong&gt;what is the ideal time to run this long range climate forecast&lt;/strong&gt;? If I were to do it now(in boreal spring) then my forecast skill is likely to be lower due to the above mentioned factor. On the other hand running a simulation later in May may be of little use to the agricultural community as farmers would not have adequate time to prepare for a drought or excess rainfall a point noted by Webster et al. in &lt;a href=&quot;http://www.ifremer.fr/cerweb/deboyer/publications/2010_Izumo_et_al_NatureG_nv.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1)&#xA;&lt;a href=&quot;http://www.ifremer.fr/cerweb/deboyer/publications/2010_Izumo_et_al_NatureG_nv.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.ifremer.fr/cerweb/deboyer/publications/2010_Izumo_et_al_NatureG_nv.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-09-25T14:06:06.947" Title="El Niño Spring Barrier - optimal time to run a long range climate forecast" Tags="|climate-models|enso|monsoon|predictability|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4705" PostTypeId="1" AcceptedAnswerId="4851" CreationDate="2015-04-17T13:30:01.970" Score="8" ViewCount="114" Body="&lt;p&gt;How can we determine the error associated with bathymetric measurements when we survey over submerged vegetation? Let's say we are using single-beam echo-sounder over a patch of Posidonia, what are the expected errors and how can we determine them? &lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-05-11T16:02:23.463" Title="What is the error in bathymetric observations in the presence of vegetation?" Tags="|instrumentation|bathymetry|vegetation|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4706" PostTypeId="1" AcceptedAnswerId="4736" CreationDate="2015-04-18T16:58:16.043" Score="5" ViewCount="258" Body="&lt;p&gt;If evapo-transpiration is high then more water vapor is taken up to the atmosphere and more condensation takes place resulting in more rainfall. But in the book &lt;em&gt;The Environment of Pakistan&lt;/em&gt; by Huma Naz Sethi, she writes that high rate of evapo-transpiration is a consequence of ineffectiveness of rainfall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do not understand this. How does high evapo-transpiration contribute to less rainfall?&lt;/p&gt;&#xA;" OwnerUserId="2793" LastEditorUserId="64" LastEditDate="2015-04-23T12:50:56.080" LastActivityDate="2015-04-24T13:16:49.820" Title="How does high rate of evapo-transpiration contribute to the ineffectiveness of rainfall?" Tags="|meteorology|rainfall|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4707" PostTypeId="2" ParentId="2822" CreationDate="2015-04-18T22:01:01.103" Score="1" Body="&lt;p&gt;Central Pacific El Niños have different effects than Eastern Pacific El Niños. For example, Modoki El Niño tends to have more hurricanes in Atlantic and Gulf of Mexico regions. Modoki El Niños may have been around going back to the 13th century, possibly before. The El Niño which developed in 2015 is a Modoki version of the phenomenon.&lt;/p&gt;&#xA;" OwnerUserId="2795" LastEditorUserId="725" LastEditDate="2015-04-19T01:48:44.457" LastActivityDate="2015-04-19T01:48:44.457" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4708" PostTypeId="1" AcceptedAnswerId="4711" CreationDate="2015-04-19T16:12:54.110" Score="4" ViewCount="2411" Body="&lt;p&gt;$\ce{FeO}$ = 70 wt%&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\ce{TiO2}$ = 30 wt%&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The molecular weight given of $\ce{FeO}$ = 72, and the mw of $\ce{TiO2}$ = 80. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first step I did was divide each wt% by their molecular weights to get a molecular proportion:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\ce{FeO}: {70 \over 72} = 0.972 $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\ce{TiO_2}: {30 \over 80} = 0.375$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then, I multiplied each proportion by the number of oxygens in each chemical formula&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$0.972 \times 1 \ \rm{oxygen} = 0.972$$&#xA;$$0.375 \times 2 \ \rm{oxygens} = 0.75$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The next step is where I get really confused. I think I'm supposed to add the two numbers above together, and divide that number into a number that is supposedly the cations assumed of the mineral? (As in 5 for plagioclase, 4 for pyroxene, 3 for olivine, etc) But I do not understand how I'm supposed to gather which number to use based on only the data given. If anyone can point me in the right direction it would be greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="2730" LastEditorUserId="725" LastEditDate="2016-09-13T12:49:40.273" LastActivityDate="2016-09-13T12:49:40.273" Title="How can I normalize this chemical analysis to a mineral with 3 cations?" Tags="|geology|geochemistry|mineralogy|homework|minerals|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4709" PostTypeId="1" AcceptedAnswerId="4732" CreationDate="2015-04-19T19:29:19.290" Score="11" ViewCount="1024" Body="&lt;p&gt;Most famous and productive source rocks for hydrocarbons are Paleozoic or Mesozoic, but there are also examples from the Neogene. Time is needed for the rock to reach the right depth and temperature for hydrocarbon generation. Younger formations are typically in an active tectonic setting; old source rock risks becoming over-matured. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the youngest and oldest source rocks that are generating hydrocarbons in economic quantities today? &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2470" LastEditDate="2015-04-20T01:16:29.897" LastActivityDate="2015-04-22T21:39:00.357" Title="The youngest and oldest source rock for hydrocarbons in economic quantities" Tags="|economic-geology|stratigraphy|petroleum|carbon|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4710" PostTypeId="1" AcceptedAnswerId="4726" CreationDate="2015-04-20T01:47:11.830" Score="9" ViewCount="126" Body="&lt;p&gt;I was shocked to learn that there were few native worms in the glaciated portion of North America. I use worms indoors to compost paper and kitchen scraps. I don't think there is much chance of transfer as my garden is on the roof of an apartment. I was still surprised that my worms are essentially invaders in some parts of this country.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thinking about all of this lead me to look up the damage done by non-native worms in North America. They have an impact on plants that once relied on the matted leaves on the forest floor. So, they can lead to more barren undergrowth. The native worms are not good at competing for some reason.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And I thought all worms were beneficial!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Still, before the most recent glaciers there were worms in these regions. So, why isn't this like turning the clock way back? In the end, after the glacier's impact fades, shouldn't there be a lot of worms again some day? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I guess sudden change is hardly ever desirable. But I'm very confused about how to identify an invaded ecosystem. &#xA;Is it just based on what humans notice? Has anyone tried to make the concept more objective?&lt;/p&gt;&#xA;" OwnerUserId="2802" LastActivityDate="2015-04-22T14:24:51.687" Title="Traits of invaded ecosystems? Are my compost worms a threat to New York?" Tags="|glaciology|soil|glaciation|glacier|environmental-protection|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4711" PostTypeId="2" ParentId="4708" CreationDate="2015-04-20T13:17:11.537" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The first step I did was divide each wt% by their molecular weights to get a molecular proportion:&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Actually that's not what you did. What you did is how much moles of each oxide you have assuming 100 grams of mineral. But that's less important now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You are mostly correct in your steps.&#xA;Eventually you have 0.972 Fe, 0.375 Ti, and 0.972 + 2×0.375 = 1.722 O.&#xA;The (non normalised) mineral formula is then:&#xA;Fe&lt;sub&gt;0.972&lt;/sub&gt;Ti&lt;sub&gt;0.375&lt;/sub&gt;O&lt;sub&gt;1.722&lt;/sub&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can easily check that it's correct using charge balance:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;0.972×2 + 0.375×4 - 1.722×2 = 0&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question now is how to normalise it. Since you were asking about 3 cations, you need to multiply everything by 3/(0.972 + 0.375), giving you:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fe&lt;sub&gt;2.165&lt;/sub&gt;Ti&lt;sub&gt;0.835&lt;/sub&gt;O&lt;sub&gt;3.835&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But that's also ugly. Usually mineral formulas are normalised to round anion numbers, so let's say you multiply it all by 5/1.722 you get:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fe&lt;sub&gt;2.822&lt;/sub&gt;Ti&lt;sub&gt;1.089&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;which is slightly prettier.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Without having any more information on the mineral as to what's it supposed to be, you can only guess. This is what we do in EMPA analyses - we know what mineral it is and we calculate the formula according to that. If we don't, we guess and try to figure out which one it is, and then calculate according to that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know much about the question, but it could be that not all iron in the mineral is Fe&lt;sup&gt;2+&lt;/sup&gt;. Some of it may be Fe&lt;sup&gt;3+&lt;/sup&gt;, but analysing both is not an easy task so most iron in minerals is reported as either all FeO or all Fe&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; regardless of what oxidation state it is actually in. So it's possible that you have (FeO + Fe&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;) = 70 wt%. If you play enough with that, you might end up with a better looking formula. Again, I don't know the question and I don't know if that is what you're supposed to do in the question.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-04-20T13:17:11.537" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4712" PostTypeId="2" ParentId="3157" CreationDate="2015-04-20T14:33:01.790" Score="5" Body="&lt;p&gt;At least in Germany, another approach is very common („Verwitterungsprofil“): the width of layers shows their competence (resistance to weathering/erosion). So competent rocks (which don’t weather easily) “stand out” opposed to soft rocks.  This is a very idealised representation of what a “real”, weatherd outcrop could look like.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edited to add: my experience with “German columns” is that grain-size profiles are indicated by a labeled axis at the top or bottom (as in &lt;a href=&quot;https://earthscience.stackexchange.com/a/3158/22&quot;&gt;kwinkunks&lt;/a&gt;’s answer). If there is no indication, it usually is a competence profile.&lt;/p&gt;&#xA;" OwnerUserId="22" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-04-21T08:39:51.227" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4713" PostTypeId="2" ParentId="2901" CreationDate="2015-04-20T14:39:04.823" Score="7" Body="&lt;p&gt;Also keep in mind that &lt;em&gt;eluvium&lt;/em&gt; and &lt;em&gt;eluvial&lt;/em&gt; have a different meaning in soil science.  There, it means leaching of soil matter or chemical substances by water.  (Usually, after some downward transport, the substances precipitate in an &lt;em&gt;iluvial&lt;/em&gt; horizon.)&lt;/p&gt;&#xA;" OwnerUserId="22" LastActivityDate="2015-04-20T14:39:04.823" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4715" PostTypeId="1" AcceptedAnswerId="4756" CreationDate="2015-04-20T18:33:03.467" Score="6" ViewCount="2578" Body="&lt;p&gt;This question is about a riddle in which the statement &quot;I am weightless&quot; was made, and the answer was &quot;wind&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to know, by definition, does the wind include the air being moved, and thus have a weight, or is it only the kinetic energy, and thus doesn't have a weight.&lt;/p&gt;&#xA;" OwnerUserId="2804" LastEditorUserId="2804" LastEditDate="2015-04-20T19:04:10.200" LastActivityDate="2015-04-27T01:44:37.447" Title="Does &quot;wind&quot; include the air molecules involved, or merely the kinetic energy?" Tags="|meteorology|wind|" AnswerCount="4" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4716" PostTypeId="2" ParentId="4715" CreationDate="2015-04-20T19:01:42.943" Score="9" Body="&lt;p&gt;Kinetic energy is the work needed to accelerate a mass. Wind defined as the velocity air (not the same as energy, as noted in comment). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the air moved by wind is a good example of kinetic energy, molecules are accelerated by a difference in pressure and moved. When the pressure difference decreases, the movement of molecules stop. So yes, the wind moves matter with &lt;a href=&quot;http://en.wikipedia.org/wiki/Density_of_air&quot; rel=&quot;nofollow&quot;&gt;weight&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, weights of gases are somehow difficult to sense, as any gas would replace the weight of the air that normally surrounds us. The weight of the air can therefore be understood as the &lt;a href=&quot;http://en.wikipedia.org/wiki/Pressure_system&quot; rel=&quot;nofollow&quot;&gt;pressure&lt;/a&gt; generated by the weight of all the air above. Air particles moves from high pressure to low pressure and so the wind is formed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A way to show how efficiently the wind is actually moving the air masses, is to consider how the wind can transport solid matter, sailing boats, wind mills and even sand and rocks. For example the &lt;a href=&quot;http://en.wikipedia.org/wiki/Harmattan&quot; rel=&quot;nofollow&quot;&gt;Harmattan&lt;/a&gt;, a wind from the North that transport huge amounts of dust from Sahara to the coast of West Africa and the Atlantic Ocean. Other air borne sediments can form thick formations of &lt;a href=&quot;http://en.wikipedia.org/wiki/Loess&quot; rel=&quot;nofollow&quot;&gt;Loess&lt;/a&gt; or other &lt;a href=&quot;http://en.wikipedia.org/wiki/Aeolian_processes&quot; rel=&quot;nofollow&quot;&gt;aeoloian&lt;/a&gt; formations as sand dunes. Also consider how the wind can move clouds and how all water in rivers and lakes therefore have been transported by the wind. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope that this, very simplified answer will make you more interested in meteorology and Earth science in general. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2015-04-25T18:56:51.757" LastActivityDate="2015-04-25T18:56:51.757" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4717" PostTypeId="1" CreationDate="2015-04-21T07:37:34.483" Score="11" ViewCount="4642" Body="&lt;p&gt;There are sometimes confusion about the magnitude of Earthquakes. What scales, other than Richter's, are used to measure the magnitude of an earthquake? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a scale where magnitude 9.0 is regarded as small and 13-14 regarded as strong?&lt;/p&gt;&#xA;" OwnerUserId="2808" LastEditorUserId="111" LastEditDate="2015-04-21T17:15:36.457" LastActivityDate="2016-11-05T03:55:10.750" Title="Are there any other earthquake magnitude scales other than Richter's?" Tags="|geophysics|earthquakes|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4718" PostTypeId="2" ParentId="4717" CreationDate="2015-04-21T09:12:38.673" Score="8" Body="&lt;p&gt;Earthquakes are measured for intensity and magnitude. &lt;a href=&quot;http://earthquake.usgs.gov/learn/topics/mag_vs_int.php&quot; rel=&quot;nofollow&quot;&gt;Magnitude and intensity&lt;/a&gt; are related but measure very different properties of the event. Magnitude is the energy released of the earthquake. It is determined from &lt;a href=&quot;http://en.wikipedia.org/wiki/Richter_magnitude_scale#Richter_magnitudes&quot; rel=&quot;nofollow&quot;&gt;measurements&lt;/a&gt;. Intensity is determined from effects on buildings, landscape and people. Naturally an earthquake with high magnitude would also generate high intensity, but the intensity depends on distance from the hypocenter and the local geological conditions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://earthquake.usgs.gov/learn/topics/mag_vs_int.php&quot; rel=&quot;nofollow&quot;&gt;Modified Mercalli Intensity scale&lt;/a&gt; is a way to rate the intensity of an earthquake, but the scale ends at XII (Damage total), not at 13-14 (XIII-XIV), as mentioned. &lt;a href=&quot;http://en.wikipedia.org/wiki/China_seismic_intensity_scale&quot; rel=&quot;nofollow&quot;&gt;China seismic intensity scale (CSIS)&lt;/a&gt;, &lt;a href=&quot;http://en.wikipedia.org/wiki/Medvedev%E2%80%93Sponheuer%E2%80%93Karnik_scale&quot; rel=&quot;nofollow&quot;&gt;Medvedev–Sponheuer–Karnik scale&lt;/a&gt; and &lt;a href=&quot;http://www.gfz-potsdam.de/sektion/erdbebengefaehrdung-und-spannungsfeld/projekte/bisherige-projekte/seismische-verletzbarkeit-risiko-intensitaetsskalen/ems98/sprachversionen-ems-98/&quot; rel=&quot;nofollow&quot;&gt;European macroseismic scale&lt;/a&gt; can reach values above ten, but not 13-14. XII on the Medvedev–Sponheuer–Karnik scale is &lt;em&gt;Very catastrophic&lt;/em&gt; and IX in &lt;em&gt;Destructive&lt;/em&gt;. &#xA;Medvedev–Sponheuer–Karnik scale is used in some Asian and European countries,  Russia, India, Israel etc. CSIS is used in mainland China. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Magnitude is also measured in different scales. Related to the Richter's scale is the &lt;a href=&quot;http://en.wikipedia.org/wiki/Moment_magnitude_scale&quot; rel=&quot;nofollow&quot;&gt;Moment magnitude scale&lt;/a&gt;, it's an updated better way to measure, but it usually produce &lt;a href=&quot;http://en.wikipedia.org/wiki/Moment_magnitude_scale#Comparison_with_Richter_scale&quot; rel=&quot;nofollow&quot;&gt;similar&lt;/a&gt; values as the old Richter's scale and the two scales are often confused in media. There are few other scales, Body wave magnitude, surface wave magnitude, but to my knowledge they also stay under 10. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some of the confusion might come from that the Richter scale is logarithmic. A difference in magnitude of 2.0 is equivalent to a factor of 1000. An earthquake measured to 9.0 is one million times stronger than an earthquake at 5.0. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="1411" LastEditDate="2015-10-23T13:43:52.503" LastActivityDate="2015-10-23T13:43:52.503" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4719" PostTypeId="2" ParentId="4717" CreationDate="2015-04-21T14:30:50.710" Score="5" Body="&lt;p&gt;I think Wikipedia provides a decent answer to this question: &lt;a href=&quot;http://en.wikipedia.org/wiki/Seismic_scale&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/Seismic_scale&lt;/a&gt;&#xA;First of all, a source of confusion is the difference between magnitude and intensity. Intensity (expressed in Roman numerals) estimates the potential for damage of an earthquake on the surface (the effects we see: people, structures...). Meanwhile, magnitude (Arabic numerals) indirectly measures the energy released by an earthquake. There is a list of different scales (&lt;a href=&quot;http://en.wikipedia.org/wiki/Seismic_scale#Seismic_intensity_scales&quot; rel=&quot;nofollow&quot;&gt;intensity&lt;/a&gt; and &lt;a href=&quot;http://en.wikipedia.org/wiki/Seismic_scale#Magnitude_scales&quot; rel=&quot;nofollow&quot;&gt;magnitude&lt;/a&gt;) in the Wikipedia article.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The more common magnitude scales are the Richter scale (a quantitative logarithmic scale that has problems capturing the overall power of the source above magnitudes around 6) developed by Charles F. Richter in 1934 and the moment magnitude scale. Today, the moment scale is preferred because it works over a wider range of earthquake sizes and is applicable globally. Also, it was developed (at least partially) by a guy called Tom Hanks!&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="200" LastEditDate="2015-04-28T18:51:19.163" LastActivityDate="2015-04-28T18:51:19.163" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4720" PostTypeId="1" AcceptedAnswerId="4722" CreationDate="2015-04-21T14:26:26.837" Score="29" ViewCount="45105" Body="&lt;p&gt;&lt;a href=&quot;https://www.biblegateway.com/passage/?search=Genesis%207&quot; rel=&quot;nofollow noreferrer&quot;&gt;Genesis 7:11-20&lt;/a&gt; presents an account of an event which, in 40 days, submerges the entire surface of the earth:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;[On] the seventeenth day of the second month — on that day&#xA;all the springs of the great deep burst forth, and the&#xA;floodgates of the heavens were opened…&lt;/p&gt;&#xA;&lt;p&gt;For forty days the flood kept coming on the earth… all the high&#xA;mountains under the entire heavens were covered. The waters rose&#xA;and covered the mountains to a depth of more than fifteen cubits&#xA;[6.86 m].&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Based on this account, my questions are:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Given the amount of water on Earth (including all the water as liquid, solid, and gas, in all possible places: the atmosphere, the surface, and underground), is there enough water to flood the whole earth until ‘all the high mountains… were covered’?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;What is the estimated rainfall intensity based on this description, and how intense is it in comparison with today’s rainfall intensity in tropical areas?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Regardless of the veracity or otherwise of the account, this makes for an interesting thought experiment.&lt;/p&gt;&#xA;" OwnerUserId="2810" OwnerDisplayName="Graviton" LastEditorUserId="-1" LastEditDate="2024-02-01T01:29:00.247" LastActivityDate="2024-02-01T01:29:00.247" Title="Is a complete global flood physically possible on Earth?" Tags="|meteorology|hypothetical|water|geomythology|flooding|" AnswerCount="7" CommentCount="18" ContentLicense="CC BY-SA 4.0" />
  <row Id="4721" PostTypeId="2" ParentId="4720" CreationDate="2015-04-21T15:20:31.527" Score="22" Body="&lt;p&gt;The &quot;precipitation rate&quot; part is easy to answer, at least to a first approximation. We have 40 days and nights (960 hours) in which to raise sea level above the peak of Mount Everest (let's round up and call it 9000m). Thus, we need a precipitation rate of around 9000/960 =~ 9.4 &lt;em&gt;metres&lt;/em&gt; per hour. For comparison, the largest rainfall ever recorded over an hour is &lt;a href=&quot;http://en.wikipedia.org/wiki/List_of_weather_records#Rain&quot;&gt;305mm&lt;/a&gt;. So a Noachian flood would require a precipitation rate over 30 times greater than the highest-ever recorded one-hour rate at a single site, sustained continuously over every point on the globe for the entire 40 days and nights.&lt;/p&gt;&#xA;" OwnerUserId="94" LastActivityDate="2015-04-21T15:20:31.527" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4722" PostTypeId="2" ParentId="4720" CreationDate="2015-04-21T16:29:44.250" Score="23" Body="&lt;p&gt;there is not enough existing water inside this geosystem IMO for such a thing to occur. Let's see these figures here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://water.usgs.gov/edu/earthhowmuch.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;One estimate of global water distribution&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oceans, Seas, &amp;amp; Bays 1,338,000,000  --  96.54% of all water&lt;/p&gt;&#xA;&#xA;&lt;p&gt;this figure means that most of the existing water at the global scale is seawater. Sea floor is quite irregular, with some abyss like pits (ex: Mariana trench), up to low water in shallow sea near continents and islands (See figure). A variable topography overall&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/cw8RF.png&quot; alt=&quot;Sea depth - division&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This mean that considering the current volume of existing sea water, at say an average of 3 km depth (hypothetical, but it doesn't change the overall reasoning), and removing the continents,  you would have to double, and probably more than double the current volume of sea water to raise the oceanic water level of 1 km, 2 km etc... or ~5 km if we consider MT Ararat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is some hypothetically (rough) calculation to illustrate. Let's say the Earth have a surface area of 510 million km&lt;sup&gt;2&lt;/sup&gt; (&lt;a href=&quot;http://en.wikipedia.org/wiki/Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;) and the overall global water (USGS link in my post) amount to 1386 million km&lt;sup&gt;2&lt;/sup&gt;. Dividing the volume by the surface provides the height, as shown by this dimensional analysis :$\frac {L^3}{L^2}=L$, which would amount to 2.71 km in height in this case. But let's not forget that this figure imply&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;a)&lt;/strong&gt; the impermeability of the surface&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;b)&lt;/strong&gt; the surface flatness.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Multiple problems further arise when considering how such an amount of hypothetical water could be suspended at once - there is a interesting debunking explaining implications here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.talkorigins.org/faqs/faq-noahs-ark.html#flood&quot; rel=&quot;nofollow noreferrer&quot;&gt;Talk Origins - 5. the Flood itself&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think &lt;a href=&quot;https://earthscience.stackexchange.com/a/4721/2810&quot;&gt;@Pont&lt;/a&gt; nicely answered the subquestion about the precipitation rate&lt;/p&gt;&#xA;" OwnerUserId="1411" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-09-15T18:41:28.160" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4723" PostTypeId="2" ParentId="4720" CreationDate="2015-04-21T23:51:15.817" Score="30" Body="&lt;p&gt;Just to add some further discussion to &lt;a href=&quot;https://earthscience.stackexchange.com/a/4721/2810&quot;&gt;@Pont&lt;/a&gt; and &lt;a href=&quot;https://earthscience.stackexchange.com/a/4722/2810&quot;&gt;@fre0n&lt;/a&gt; excellent answers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem of the &lt;a href=&quot;http://en.wikipedia.org/wiki/Flood_geology&quot; rel=&quot;nofollow noreferrer&quot;&gt;water needed&lt;/a&gt; to submerge the world during the &lt;a href=&quot;https://www.biblegateway.com/passage/?search=Genesis%207&quot; rel=&quot;nofollow noreferrer&quot;&gt;Genesis flood&lt;/a&gt; have been discussed for centuries. The narrative could seem legit as  traces of marine condition can be seen even in high mountains. The Biblical flood was the most logic explanation for marine fossils and wave patterns far away from any coast. Moreover, at the time when the Bible was written in the Levant, there might still have been a collective memory of sudden sea level rise from the possible opening of Bosporus and &lt;a href=&quot;http://en.wikipedia.org/wiki/Black_Sea_deluge_hypothesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;flooding of the Black Sea&lt;/a&gt;. Other experiences, as &lt;a href=&quot;http://www.bbc.co.uk/history/ancient/greeks/minoan_01.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;tsunamis&lt;/a&gt; formed in the tectonic active Eastern Mediterranean would also add to the idea of flooding as a divine respond to human actions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Early scientists that described and compared features in the nature, e.g. &lt;a href=&quot;http://muslimheritage.com/article/contribution-ibn-sina-development-earth-sciences&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ibn-Sinaa&lt;/a&gt;, could also see that some rocks was formed by water. They added the superposition principle, that younger rocks are situated above older rocks and that the processes that formed the rocks &lt;a href=&quot;http://en.wikipedia.org/wiki/Uniformitarianism&quot; rel=&quot;nofollow noreferrer&quot;&gt;continues today&lt;/a&gt; and must have taken long time. What they could see, describe and test was a continuation of the earlier ideas of flooding, but they used reason instead of dogma. Modern disciplines of science, as &lt;a href=&quot;http://en.wikipedia.org/wiki/Radiometric_dating&quot; rel=&quot;nofollow noreferrer&quot;&gt;radiometric dating&lt;/a&gt; and &lt;a href=&quot;http://en.wikipedia.org/wiki/Evolutionary_taxonomy&quot; rel=&quot;nofollow noreferrer&quot;&gt;taxonomy&lt;/a&gt;, have further refined our understanding of time and the relation between water and dry ground, but we are still building on the traditions of earlier scholars as Ibn-Sinaa. Sometimes we prove them wrong, just like future scientists will (hopefully) prove us wrong, but the human wish to understand the nature around us can easily be traced back to Old Testament and before. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sea levels are constantly changing during the history of Earth. There is a number of parameters that controls the global sea level, some are &lt;a href=&quot;http://en.wikipedia.org/wiki/Sea_level#Geological_influences&quot; rel=&quot;nofollow noreferrer&quot;&gt;slow&lt;/a&gt; but have a large impact. E.g. during Ordovician, the sea level might have been 3-400m higher than today. Not enough to reach the foot of modern Mt Ararat, but the planet was certainly more blue when the first fishes appeared. Also during Cretaceous, the sea level was 2-300m higher than today and more recent, in early Holocene, the sea level was 120m lower than today. Our ancestors could walk (and maybe a short swim or paddle) from Asia to Alaska, from Java to Australia, and across the Black Sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/VR9VM.png&quot; alt=&quot;Picture from the net. I hope it&amp;#39;s correct and allowed to use.&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So where did the water go? At colder conditions water can be be trapped in ice shields, glaciers. Antarctica and Greenland holds a rather large fraction of the global fresh water. But most water are in the oceans, and larger sea level changes must be caused by changes of the oceans. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/q7DdG.png&quot; alt=&quot;USGS – Earth&amp;#39;s water distribution By Cmglee (Own work) [CC BY-SA 3.0 (http://creativecommons.org/licenses/by-sa/3.0) or GFDL (http://www.gnu.org/copyleft/fdl.html)], via Wikimedia Commons&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The oceanic crust is, relatively to the continental crust, thin and soft, but get harder and chemically heavier with age. The oceanic crust press down the &lt;a href=&quot;http://en.wikipedia.org/wiki/Asthenosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;asthenosphere&lt;/a&gt; and this results in more space for water, and the sea level sinks (in relation to the &lt;a href=&quot;http://en.wikipedia.org/wiki/Geoid&quot; rel=&quot;nofollow noreferrer&quot;&gt;geoid&lt;/a&gt;). Mid-ocean volcanism on the other hand lifts the seafloor and forces the sea level to rise. Temperature of water is also a factor to consider. Warm water is has less density and occupies larger volume. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/zrsmz.png&quot; alt=&quot;Phanerozoic Sea Level&amp;quot;. Licensed under CC BY-SA 3.0 via Wikimedia Commons&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The total change in sea level in the past 500 million years have been estimated to about 500m, this is impressive, but far more than the 3,896m of Mt Ararat, that was supposed to be covered in the Genesis &lt;a href=&quot;http://en.wikipedia.org/wiki/Flood_myth&quot; rel=&quot;nofollow noreferrer&quot;&gt;flood narrative&lt;/a&gt;. As mentioned, there might be more &lt;a href=&quot;http://www.sciencemag.org/content/344/6189/1265.abstract?sid=d573efc5-c389-4b1a-a4be-19fa8a3301de&quot; rel=&quot;nofollow noreferrer&quot;&gt;water&lt;/a&gt; trapped in the &lt;a href=&quot;http://en.wikipedia.org/wiki/Transition_zone_%28Earth%29&quot; rel=&quot;nofollow noreferrer&quot;&gt;mantle transition zone&lt;/a&gt;, but it's hard to see how it could have slipped out to form liquid water, and even more difficult, how it could get back to the mantle, against gravity, after the flood. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, as a homage to the Biblical believes, there could be an interesting link between sea level changes and mass extinction. Changing sea levels, especially when it happens rapidly, results in new conditions that species might not have time to &lt;a href=&quot;http://en.wikipedia.org/wiki/Adaptation&quot; rel=&quot;nofollow noreferrer&quot;&gt;adapt&lt;/a&gt; to. The connection is discussed in &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0012825299000550&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; article by Hallam and Wignall, 1999 (&lt;a href=&quot;http://studentresearch.wcp.muohio.edu/extinctionsradiations/massextinctionsealevel.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mass extinctions and sea-level changes&lt;/a&gt;). The article is also a good example of scientific methods and reason. The language in a scientific article might not be so colorful as in Genesis, but it can open a world far more complex and wonderful than any dogma.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, a reading tip: &#xA;One solution is proposed in Umberto Eco's &lt;a href=&quot;http://www.goodreads.com/book/show/10506.The_Island_of_the_Day_Before&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Island of the Day Before&lt;/a&gt;, maybe the water was borrowed from another day, as the Earth contains two days, separated by the &lt;a href=&quot;http://en.wikipedia.org/wiki/International_Date_Line&quot; rel=&quot;nofollow noreferrer&quot;&gt;date line&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-09-12T08:39:24.303" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="4724" PostTypeId="2" ParentId="4720" CreationDate="2015-04-22T02:03:24.797" Score="-1" Body="&lt;p&gt;If you'll accept a much slower rain it could happen.  Consider:  As others have shown there is not enough water &lt;strong&gt;on Earth&lt;/strong&gt; to do this.  Since there's no feasible mechanism to get all the water on Earth into rain in the first place this isn't all that important anyway.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Instead, lets look elsewhere for the source of our rain:  A large comet.  It's captured by the Earth with the assistance of the Moon but it's in an orbit with a very low perigee.  Comet stuff is shed, hits the atmosphere and comes down.  Since it's mostly gas and ice you get rain, rain and more rain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This can't happen in 40 days, though--there has to be enough time for it to cool.  If that much water comes down in 40 days it's going to make Venus look positively arctic by comparison.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus it's possible for the Earth to become a waterworld like in the movie but not like in &lt;em&gt;Genesis&lt;/em&gt;.&lt;/p&gt;&#xA;" OwnerUserId="1160" LastActivityDate="2015-04-22T02:03:24.797" CommentCount="13" ContentLicense="CC BY-SA 3.0" />
  <row Id="4726" PostTypeId="2" ParentId="4710" CreationDate="2015-04-22T14:24:51.687" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The native worms are not good at competing for some reason.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There's a reason for that. There are &lt;strong&gt;no&lt;/strong&gt; native earthworms in New York.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Still, before the most recent glaciers there were worms in these regions.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;North America has been hammered by multiple glaciations for the last two million years. It wasn't just the areas covered by ice that lost their earthworms. The northern forest, or taiga extended to the Gulf Coast at the peak of the last glaciation. You have to drive to Ontario to see the taiga now. The Great Plains were the mammoth steppe, very cold and very dry. Most of the US is depleted of native earthworms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Invasive earthworms are your enemy if you like maple syrup. Sugar maples take a couple of years to germinate, and only need a nice pile of duff (leaf detritus that hasn't been consumed by earthworms) in which to do so.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-04-22T14:24:51.687" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4727" PostTypeId="2" ParentId="4720" CreationDate="2015-04-22T14:46:11.670" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;1.Given the amount of water on Earth (including all the water as liquid, solid, and gas, in all possible places: the atmosphere, the surface, and underground), is there enough water to flood the whole earth until ‘all the high mountains… were covered’?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes.  According to &lt;a href=&quot;http://www.newscientist.com/article/dn25723-massive-ocean-discovered-towards-earths-core.html&quot; rel=&quot;noreferrer&quot;&gt;Massive 'ocean' discovered towards Earth's core&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A reservoir of water three times the volume of all the oceans has been discovered deep beneath the Earth's surface. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Considering that the average depth of the ocean is 2.3 miles and the Earth is 71% water, three times this amount would be about the amount needed to reach the top of the highest mountains.  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;2.What is the estimated rainfall intensity based on this description, and how intense is it in comparison with today’s rainfall intensity in tropical areas?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There is no way to estimate rain fall from the description, because Genesis makes clear water came from &quot;the deep&quot; as well as from above.  For example the passage qouted in the OP says &quot;springs of the great deep burst forth&quot; and Genesis 8:2 says &quot;the fountains also of the deep and the windows of heaven were stopped, and the rain from heaven was restrained. &quot;&lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2015-04-22T14:46:11.670" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4728" PostTypeId="1" AcceptedAnswerId="4733" CreationDate="2015-04-22T19:32:07.877" Score="29" ViewCount="8647" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/SY7gr.png&quot; alt=&quot;Relative sea-level data for Hudson Bay&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is the sea level in Hudson Bay decreasing so much? Hudson Bay is pretty far up north, much closer to glaciers. Would it make sense for it to recede at this level with sources of fresh water relatively close? &lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="28050" LastEditDate="2015-04-22T23:26:10.540" LastActivityDate="2022-01-27T18:38:30.897" Title="Why is relative sea-level falling in Hudson Bay?" Tags="|geology|oceanography|sea-level|ice-sheets|glaciation|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4729" PostTypeId="2" ParentId="4728" CreationDate="2015-04-22T19:42:35.057" Score="14" Body="&lt;p&gt;Because of post glacial rebound. The asthenosphere was pressed down under &lt;a href=&quot;http://en.wikipedia.org/wiki/Laurentide_ice_sheet&quot; rel=&quot;noreferrer&quot;&gt;Laurentide ice sheet&lt;/a&gt; during last ice age and is now finding a new balance, without the weight of the ice. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that around the ice sheet, the land is actually sinking today, like when ones partner gets up from a waterbed mattress. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/xvigt.jpg&quot; alt=&quot;&amp;quot;PGR Paulson2007 Rate of Lithospheric Uplift due to PGR&amp;quot; by Erik Ivins, JPL. -  Licensed under Public Domain via Wikimedia Commons&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2015-04-22T19:47:43.393" LastActivityDate="2015-04-22T19:47:43.393" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4730" PostTypeId="2" ParentId="4535" CreationDate="2015-04-22T19:55:52.120" Score="0" Body="&lt;p&gt;Since the Earth can't orbit around anything (making it a planet) it would float around (like a comet) waiting for a larger object to pull it into its gravitational field.  The larger object would probably be a star (like the sun, but a different one).  Life might survive?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or if left tethered, it might smash into another rogue planet, destroying itself in the process.   No life would not survive.&lt;/p&gt;&#xA;" OwnerUserId="2437" LastActivityDate="2015-04-22T19:55:52.120" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4731" PostTypeId="2" ParentId="4720" CreationDate="2015-04-22T20:15:29.703" Score="2" Body="&lt;p&gt;Without requiring any rainfall, if you accept a theoretical scenario of a &quot;dead Earth&quot;, meaning with no more active tectonics, no flux of heat from the mantle/core and given a long-enough time to almost completely erode mountains, then yes, a complete global flood may be possible. Just imagine to displace all the rocks that today are above the average sea level into the oceanic basins, then let them to compact (reducing porosity) and to reach isostatic equilibrium, pushing water above the sediments by density difference. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The thought experiment may then continue, calculating the average altitude of sediments and the average height of the water column above the surface in that case. A rough estimation should be in the order of a couple thousands meters of water above the global seafloor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However I do not suppose that this may happen in 40 days, or anytime soon.&lt;/p&gt;&#xA;" OwnerUserId="585" LastActivityDate="2015-04-22T20:15:29.703" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4732" PostTypeId="2" ParentId="4709" CreationDate="2015-04-22T21:24:22.017" Score="6" Body="&lt;p&gt;According &quot;&lt;a href=&quot;http://link.springer.com/article/10.1134/S0012500811050053&quot;&gt;The youngest natural oil on earth&lt;/a&gt;&quot; Doklady Chemistry vol. 438, pages 144-147:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Prior to this paper, it was known that oil of the Guaymas basin is from young sediments and is 5000 years old.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, their work shows that oil in the Kamchatka volcanic area is &quot;less than 50 years old&quot;.  Oil is shown through carbon dating to have formed between 1962 and 1973.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the opposite extreme, &lt;a href=&quot;http://www.nytimes.com/1986/09/02/science/science-watch-the-oldest-oil-ever-found.html&quot;&gt;this 1986 New York times article&lt;/a&gt; reports:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A team of geologists working for the Australian Government's Bureau of Mineral Resources reports in the journal Nature that it has discovered oil formed from the decayed remains of organisms that lived 1.4 billion years ago, when the earth was young. After the group drilled a 1,100-foot-deep test hole beneath the McArthur Basin in northern Australia, the oldest oil of its kind ever found bubbled to the surface. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Tiny amounts of oil as old &lt;a href=&quot;http://news.bbc.co.uk/2/hi/science/nature/864777.stm&quot;&gt;as 3.2 billion years have been found more recently&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2015-04-22T21:39:00.357" LastActivityDate="2015-04-22T21:39:00.357" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4733" PostTypeId="2" ParentId="4728" CreationDate="2015-04-22T23:23:29.887" Score="35" Body="&lt;p&gt;&lt;strong&gt;The area is experiencing &lt;a href=&quot;https://en.wikipedia.org/wiki/Post-glacial_rebound&quot; rel=&quot;nofollow noreferrer&quot;&gt;post-glacial isostatic rebound&lt;/a&gt;.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Much of Canada was covered in an extensive ice sheet in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Last_glacial_period&quot; rel=&quot;nofollow noreferrer&quot;&gt;last glacial period&lt;/a&gt; (the 'Ice Age'), from about 110 ka until 12 ka. The ice in the Hudson Bay area was among the last to melt:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/FEFew.png&quot; alt=&quot;Ice retreat in North America&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;A thick ice sheet depresses the crust (the lithosphere), making a small dent in the uppermost mantle (the &lt;a href=&quot;https://en.wikipedia.org/wiki/Asthenosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;asthenosphere&lt;/a&gt;) in the process. Well, not that small: p 375 in &lt;a href=&quot;https://books.google.ca/books?id=yRMgYc-8mTIC&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gornitz&lt;/a&gt; (2009, &lt;em&gt;Encyclopedia of Paleoclimatology and Ancient Environments&lt;/em&gt;) says it could be 800 m for a 3000 metre-thick ice sheet!&lt;/p&gt;&#xA;&lt;p&gt;Since the asthenosphere is highly viscous, it takes a long time time for the depression to 'bounce' back up. This map from Natural Resources Canada shows the current rate:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/kd0gN.jpg&quot; alt=&quot;Isostatic rebound rate in Canada&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;Since &lt;em&gt;global&lt;/em&gt; sea-level is &lt;a href=&quot;https://en.wikipedia.org/wiki/Current_sea_level_rise&quot; rel=&quot;nofollow noreferrer&quot;&gt;currently rising&lt;/a&gt; at about 3 mm/a, a &lt;em&gt;local&lt;/em&gt; uplift at this rate will break even. Anything more will result in relative sea-level fall, as we see in Hudson Bay (as well as in Scandinavia, the UK, Alaska, and elsewhere — &lt;a href=&quot;https://tidesandcurrents.noaa.gov/sltrends/sltrends.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this map is wonderful&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;Interesting, for geologists anyway, is the sedimentological record this leaves. I love this example of raised beaches and a small delta experiencing &lt;a href=&quot;https://www.sepmstrata.org/Terminology.aspx?id=forced%20regression&quot; rel=&quot;nofollow noreferrer&quot;&gt;forced regression&lt;/a&gt; on the shores of Hudson Bay:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/5ugZd.jpg&quot; alt=&quot;Forced regression of small delta&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;Last thing — you asked:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Would it make sense for it to recede at the level that it is&#xA;receding with sources of freshwater relatively close?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Since Hudson Bay is connected to the world's ocean, mainly through Hudson Strait, the runoff into the Bay has no measurable effect on the water level.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Credit&lt;/strong&gt;&#xA;&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Retrait_des_glaces_en_Am%C3%A9rique.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ice retreat map&lt;/a&gt; by TKostolany, licensed CC-BY-SA. Rebound map by NRCan, free of copyright. Google Maps image contains own credit.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2022-01-27T18:38:30.897" LastActivityDate="2022-01-27T18:38:30.897" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="4735" PostTypeId="1" CreationDate="2015-04-23T08:45:39.457" Score="7" ViewCount="75" Body="&lt;p&gt;As anybody knows, there are a lot of forests. &#xA;I stumbled upon the question whether these have any effect on the global wind-systems. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Imagine the following situation. All trees suddenly die in an instant. Soon the leaves will dry and fall down, thus only the wood-part remains standing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The wind can now blow much easier through the trees.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;But will this really have an effect?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do forests influence the windsystems around the earth significantly? How would these winds change, if at all? Would storm-like squalls be more common?&lt;/p&gt;&#xA;" OwnerUserId="2823" LastEditorUserId="115" LastEditDate="2015-04-24T01:36:58.647" LastActivityDate="2015-04-24T01:36:58.647" Title="How big is the influence of tree leaves on global windsystems?" Tags="|meteorology|hypothetical|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4736" PostTypeId="2" ParentId="4706" CreationDate="2015-04-23T12:45:19.113" Score="5" Body="&lt;p&gt;I just read the paragraph about the &lt;em&gt;Effectiveness of Rainfall&lt;/em&gt; in UNIT.2 Climate of Pakistan, p. 30.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The author bring the topic of the rain being ineffective in a context where the rain is expected for crops and farming, or in other words, on the potential usefulness of the said rain for crops, which is quite low considering the climatic context in this area. I do not think the author is trying to explain the actual process of evapotranspiration for the area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a summary of the factors bring by the author on why the current pluvial regime on Pakistan is not 'effective':&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Rainfall is mainly from monsoon. Monsoon rain is not regular (and therefore unreliable for planning long term with rain as an only source of water). For instance ,distribution, amount and timing varies.&lt;/li&gt;&#xA;&lt;li&gt;High temperatures during the monsoon season imply high potential evapotranspiration so a greater proportion of the rainfall is evaporated rather than infiltrated to be available for crop growth&lt;/li&gt;&#xA;&lt;li&gt;Rain when it occurs is quite intense, with often a low infiltration rate and flow away instead of recharging ground moisture&lt;/li&gt;&#xA;&lt;li&gt;Insufficient rain during winter to compensate&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Therefore, irrigation and other means to store and distribute water should be used in the long term to efficiently use the water input, in regard with the potential use for water.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastEditorUserId="1411" LastEditDate="2015-04-24T13:16:49.820" LastActivityDate="2015-04-24T13:16:49.820" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4737" PostTypeId="2" ParentId="4735" CreationDate="2015-04-23T12:55:49.540" Score="3" Body="&lt;p&gt;Wind is largely driven by differences in atmospheric pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The effect of trees and forests is to force the winds to flow over the forests. The loss of leaves in forests would result in winds having a larger impact at ground level. Also, due to the change in the surface roughness to air flow because of the loss of leaves the wind would lose less of its energy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It has been suggested in &lt;a href=&quot;http://www.atmos-chem-phys.net/13/1039/2013/acp-13-1039-2013.html&quot; rel=&quot;nofollow&quot;&gt;this paper&lt;/a&gt;, though not yet fully accepted by many, that water vapour in the atmosphere due to evaporation and transpiration can contain sufficient latent heat to accelerate air and drive winds.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-04-23T12:55:49.540" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4738" PostTypeId="2" ParentId="4717" CreationDate="2015-04-23T12:57:47.843" Score="5" Body="&lt;p&gt;The problem with most scales is that they become saturated after a certain magnitude.&lt;/p&gt;&#xA;&lt;p&gt;3 scales can be named which fall in this category&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Local Magnitude/Richter (ML):&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;From &lt;a href=&quot;http://en.wikipedia.org/wiki/Richter_magnitude_scale#Richter_magnitudes&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Richter magnitude of an earthquake is determined from the logarithm of the amplitude of waves recorded by seismographs (adjustments are included to compensate for the variation in the distance between the various seismographs and the epicenter of the earthquake). The original formula is:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$M_\mathrm{L} = \log_{10} A - \log_{10} A_\mathrm{0}(\delta) = \log_{10} [A / A_\mathrm{0}(\delta)],$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; is the maximum excursion of the Wood-Anderson seismograph, the empirical function &lt;span class=&quot;math-container&quot;&gt;$A_0$&lt;/span&gt; depends only on the epicentral distance of the station, &lt;span class=&quot;math-container&quot;&gt;$\delta$&lt;/span&gt;. In practice, readings from all observing stations are averaged after adjustment with station-specific corrections to obtain the &lt;span class=&quot;math-container&quot;&gt;$M_\text{L}$&lt;/span&gt; value.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Technically this scale is valid only for earthquakes in the California region.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Body wave Magnitude (&lt;span class=&quot;math-container&quot;&gt;$M_b$&lt;/span&gt;)&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;From &lt;a href=&quot;http://en.wikipedia.org/wiki/Body_wave_magnitude&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Body wave magnitude (&lt;span class=&quot;math-container&quot;&gt;$m_b$&lt;/span&gt;) is a way of determining the size of an earthquake, using the amplitude of the initial P-wave to calculate the magnitude. The P-wave is a type of body wave that is capable of traveling through the earth at a velocity of around 5 to 8 km/s, and is the first wave from an earthquake to reach a seismometer. Because of this, calculating the body wave magnitude can be the quickest method of determining the size of an earthquake that is of a large distance from the seismometer.&lt;/p&gt;&#xA;&lt;p&gt;Limitations in the calculation method mean that body wave magnitude saturates at around 6-6.5 &lt;span class=&quot;math-container&quot;&gt;$m_b$&lt;/span&gt;, with the figure staying the same even when the moment magnitude may be higher.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Surface wave Magnitude (&lt;span class=&quot;math-container&quot;&gt;$M_s$&lt;/span&gt;)&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;From &lt;a href=&quot;http://en.wikipedia.org/wiki/Surface_wave_magnitude#Definition&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The formula to calculate surface wave magnitude is:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$M = \log_{10}\left(\frac{A}{T}\right)_{\text{max}} + \sigma(\Delta)$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; is the maximum particle displacement in surface waves (vector sum of the two horizontal displacements) in μm, &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; is the corresponding period in s, Δ is the epicentral distance in °, and&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ \sigma(\Delta) = 1.66\cdot\log_{10}(\Delta) + 3.5$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This scale gets saturated at around &lt;span class=&quot;math-container&quot;&gt;$M_s$&lt;/span&gt;=8.4&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;The advantage of using &lt;strong&gt;Moment Magnitude scale(MW)&lt;/strong&gt; is that it does not saturate.&lt;/p&gt;&#xA;&lt;p&gt;From &lt;a href=&quot;http://en.wikipedia.org/wiki/Surface_wave_magnitude#Definition&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The symbol for the moment magnitude scale is &lt;span class=&quot;math-container&quot;&gt;$M_\mathrm{w}$&lt;/span&gt;, with the subscript  &lt;span class=&quot;math-container&quot;&gt;$\mathrm{w}$&lt;/span&gt; meaning mechanical work accomplished. The moment magnitude &lt;span class=&quot;math-container&quot;&gt;$M_\mathrm{w}$&lt;/span&gt; is a dimensionless number defined by&#xA;&lt;span class=&quot;math-container&quot;&gt;$$M_\mathrm{w} = {\frac{2}{3}}\log_{10}(M_0) - 6,$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$M_0$&lt;/span&gt; is the seismic moment in N⋅m (&lt;span class=&quot;math-container&quot;&gt;$10^7$&lt;/span&gt; dyne⋅cm).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;From &lt;a href=&quot;http://en.wikipedia.org/wiki/Moment_magnitude_scale&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The magnitude(&lt;span class=&quot;math-container&quot;&gt;$M_0$&lt;/span&gt;) is based on the seismic moment of the earthquake, which is equal to the rigidity of the Earth multiplied by the average amount of slip on the fault and the size of the area that slipped.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This scale is more useful in a sense that it provides some insight into the fault plane geometry of the earthquake based on parameter &lt;span class=&quot;math-container&quot;&gt;$M_0$&lt;/span&gt;.&lt;/p&gt;&#xA;" OwnerUserId="594" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-04-23T13:37:39.857" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4740" PostTypeId="1" AcceptedAnswerId="4741" CreationDate="2015-04-23T17:37:24.050" Score="6" ViewCount="89" Body="&lt;p&gt;It sounds logical, but I wonder if the regeneration rate of nature (natural absorption of $\ce{CO_2}$) is decreased after an environmental catastrophe (resource stock depletion, etc.)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or are most catastrophes mainly caused by the decrease of regeneration rate of nature?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would really appreciate academic references on this issue.&lt;/p&gt;&#xA;" OwnerUserId="2827" LastEditorUserId="115" LastEditDate="2015-04-24T01:31:53.113" LastActivityDate="2015-04-24T01:35:13.380" Title="Regeneration rate of nature after environmental catastrophes" Tags="|resources|environmental-protection|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4741" PostTypeId="2" ParentId="4740" CreationDate="2015-04-23T18:26:14.657" Score="5" Body="&lt;p&gt;It sounds like you are asking about plants taking up carbon at different stages of &lt;a href=&quot;http://en.wikipedia.org/wiki/Ecological_succession&quot; rel=&quot;nofollow&quot;&gt;Ecological Succession&lt;/a&gt; that occur after some catastrophic event (e.g. a wildfire or lava flow).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the prior ecosystem was dominated by live vegetation such that the detritus emitting $\ce{CO_2}$ was much less than the $\ce{CO_2}$ uptake by plants, then a catastrophe will generally lower the $\ce{CO_2}$ uptake. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the catastrophe (e.g. lava flow or land slide) creates a new land-surface, then primary succession begins with the establishment of generally small forms of life and $\ce{CO_2}$ sequestration would be minimal. Otherwise, if the catastrophe leaves behind some form of the prior ecological community, then secondary succession can occur and the region would be able to return to higher $\ce{CO_2}$ sequestration rates much sooner relative to a primary succession event.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might enjoy the following references:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&quot;Carbon sequestration is related to mycorrhizal fungal community shifts during long-term succession in boreal forests.&quot;&#xA;available here: &lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pubmed/25494880&quot; rel=&quot;nofollow&quot;&gt;http://www.ncbi.nlm.nih.gov/pubmed/25494880&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&quot;Chapter 3: Effects of Disturbance, Succession and Management on Carbon Sequestration&quot; in the book &quot;Carbon Sequestration in Forest Ecosystems&quot; available here: &lt;a href=&quot;http://link.springer.com/chapter/10.1007%2F978-90-481-3266-9_3&quot; rel=&quot;nofollow&quot;&gt;http://link.springer.com/chapter/10.1007%2F978-90-481-3266-9_3&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="543" LastEditorUserId="115" LastEditDate="2015-04-24T01:35:13.380" LastActivityDate="2015-04-24T01:35:13.380" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4742" PostTypeId="1" AcceptedAnswerId="4770" CreationDate="2015-04-23T21:06:26.603" Score="4" ViewCount="137" Body="&lt;p&gt;Would anyone know of references that give detailed explanations on concepts such as moving grids and nested grids in models?&lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorUserId="192" LastEditDate="2015-04-27T21:18:35.437" LastActivityDate="2015-04-28T17:44:29.937" Title="References for moving and nested grids in models" Tags="|models|reference-request|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4743" PostTypeId="1" AcceptedAnswerId="4744" CreationDate="2015-04-23T22:14:40.903" Score="3" ViewCount="240" Body="&lt;p&gt;I've found that there may possibly be many meanings of &quot;objectively analyzed&quot; and &quot;objective analysis&quot; in modeling and data assimilation. What are some of the accepted meanings?&lt;/p&gt;&#xA;" OwnerUserId="2645" LastActivityDate="2015-04-24T01:27:55.667" Title="Meaning of &quot;Objectively analyzed&quot;" Tags="|models|atmosphere-modelling|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4744" PostTypeId="2" ParentId="4743" CreationDate="2015-04-24T01:02:08.840" Score="4" Body="&lt;p&gt;In my field of oceanography, objective analysis (&lt;strong&gt;OA&lt;/strong&gt;) is often taken as a synonym of optimal interpolation (&lt;strong&gt;OI&lt;/strong&gt;). (e.g. &lt;a href=&quot;https://books.google.com/books?hl=en&amp;amp;lr=&amp;amp;id=59fEAgAAQBAJ&amp;amp;oi=fnd&amp;amp;pg=PP1&amp;amp;dq=emery%20thomson&amp;amp;ots=Go9-M8l-mf&amp;amp;sig=RveHg386O6cEiW7jprmvt4G9WBg#v=onepage&amp;amp;q=emery%20thomson&amp;amp;f=false&quot; rel=&quot;nofollow&quot;&gt;Emery &amp;amp; Thomson&lt;/a&gt;, Section 4.2; and &lt;a href=&quot;http://marine.rutgers.edu/dmcs/ms615/JW-lecture-OI.pdf&quot; rel=&quot;nofollow&quot;&gt;in many lectures&lt;/a&gt;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same method is also referred to as objective mapping or Gauss-Markov smoothing. In this case OA is a least squared interpolation where the estimate is unbiased and the expected error is a minimum in the least squares sense.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In many other cases, objective analysis is taken to be a specific type of optimal interpolation. A good example is the group from &lt;a href=&quot;http://modb.oce.ulg.ac.be/wiki/upload/diva_intro.pdf&quot; rel=&quot;nofollow&quot;&gt;University of Liege&lt;/a&gt;. In this case OI includes other methods like &lt;a href=&quot;http://en.wikipedia.org/wiki/Kriging&quot; rel=&quot;nofollow&quot;&gt;kriging&lt;/a&gt;, &lt;a href=&quot;http://en.wikipedia.org/wiki/Barnes_interpolation&quot; rel=&quot;nofollow&quot;&gt;successive corrections&lt;/a&gt; or the Cressman method. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In my case, I tend to follow the nomenclature and suggestions by &lt;a href=&quot;http://www.academia.edu/download/31042285/10.1.1.47.2607.pdf&quot; rel=&quot;nofollow&quot;&gt;Ide et al. (1997)&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="115" LastEditDate="2015-04-24T01:27:55.667" LastActivityDate="2015-04-24T01:27:55.667" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4745" PostTypeId="1" AcceptedAnswerId="4748" CreationDate="2015-04-24T09:58:42.010" Score="8" ViewCount="1156" Body="&lt;p&gt;Are coral cays and coral atolls just a different type of volcanic island? When I hear: &quot;volcanic island&quot; I think at places like Moorea or Hawaii, but ultimately, coral cays and coral atolls lay their foundation on the residuals of a volcano, right?&lt;/p&gt;&#xA;" OwnerUserId="2830" LastEditorUserId="2830" LastEditDate="2015-04-24T14:13:19.300" LastActivityDate="2015-04-24T14:13:19.300" Title="Are coral cays and coral atolls just volcanic islands?" Tags="|geology|volcanology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4746" PostTypeId="2" ParentId="4715" CreationDate="2015-04-24T10:23:22.310" Score="3" Body="&lt;p&gt;Looking up the &lt;a href=&quot;http://www.oxforddictionaries.com/definition/english/wind&quot; rel=&quot;nofollow&quot;&gt;definition of &quot;wind&quot;&lt;/a&gt; in the Oxford English Dictionary, the relevant definition is:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The perceptible natural movement of the air, especially in the form of&#xA;  a current of air blowing from a particular direction&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It is the &lt;em&gt;movement&lt;/em&gt; of the air, rather than the air itself, that is referred to. It is thus reasonable to say that while air has mass and hence weight, wind does not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whether dictionary definitions are important in the context and spirit of a riddle is, of course, up for debate :-)&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2015-04-24T10:23:22.310" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4747" PostTypeId="1" CreationDate="2015-04-24T12:39:03.663" Score="10" ViewCount="1486" Body="&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/New_York_City&quot;&gt;New York City&lt;/a&gt; has about 8.5 million people living in an area of 300 square miles which gives a population density of 28,300 people per square mile.  The food required to support such a high population density is mostly grown outside of that 300 square mile area.  Likewise, the fresh water required to support that population is not collected within that area. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How much land outside of NYC is effectively dedicated to supporting it?  More generally, how much reasonably productive land does it take to feed and hydrate a human being on average?&lt;/p&gt;&#xA;" OwnerUserId="53" LastEditorUserId="53" LastEditDate="2015-04-24T14:24:09.110" LastActivityDate="2015-04-25T10:47:25.823" Title="How much land does it take to support New York City?" Tags="|human-influence|water|land-surface|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4748" PostTypeId="2" ParentId="4745" CreationDate="2015-04-24T14:03:26.960" Score="11" Body="&lt;p&gt;&lt;strong&gt;No, they are not necessarily volcanic.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both of these terms, &lt;a href=&quot;http://en.wikipedia.org/wiki/Coral_reef#Types&quot; rel=&quot;noreferrer&quot;&gt;along with many others&lt;/a&gt; like &lt;em&gt;fringing reef&lt;/em&gt; and &lt;em&gt;barrier reef&lt;/em&gt;, are just morphologic — to do with shape. They tend not to imply anything genetic — to do with origin. (The separation of description and interpretation is an important principle in observational sciences like geoscience.)&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Cay&lt;/strong&gt; &amp;nbsp; A low island, often of sand or coral. &lt;a href=&quot;http://en.wiktionary.org/wiki/cay&quot; rel=&quot;noreferrer&quot;&gt;See Wiktionary.&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Atoll&lt;/strong&gt; &amp;nbsp; A ring-shaped coral reef. &lt;a href=&quot;http://www.oxforddictionaries.com/definition/english/atoll&quot; rel=&quot;noreferrer&quot;&gt;See Oxford English Dictionary.&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The name &lt;em&gt;Cay&lt;/em&gt; is sometimes applied more generally to an island or group of islands. In some cases, as in &lt;a href=&quot;http://en.wikipedia.org/wiki/Cay_Sal_Bank&quot; rel=&quot;noreferrer&quot;&gt;Cay Sal Bank&lt;/a&gt;, Bahamas, the feature is actually an atoll: a ring-shaped reef. Cay Sal Bank is one of the largest atolls in the world, and &lt;a href=&quot;https://www.livingoceansfoundation.org/publication/khaled-bin-sultan-living-oceans-foundation-2011-coral-reef-assessment-cay-sal-bank-bahamas/&quot; rel=&quot;noreferrer&quot;&gt;did not form on a volcano&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Charles Darwin hypothesized in his monograph &lt;em&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/The_Structure_and_Distribution_of_Coral_Reefs&quot; rel=&quot;noreferrer&quot;&gt;The structure and distribution of coral reefs&lt;/a&gt;&lt;/em&gt; that atolls form when a fringing reef around a volcanic islands grows as the volcano subsides:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/pM4eR.png&quot; alt=&quot;An atoll forming on a volcano&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Indeed, Darwin turned out to be correct that atolls often have a volcanic origin, but Cay Sal Bank is a counter-example. I think it's fair to say that most people would assume that origin though, and lots of Internet definitions , so it's notable if an atoll formed some other way, e.g. on a non-volcanic seamount (see &lt;a href=&quot;http://dx.doi.org/10.1029/GM043p0061&quot; rel=&quot;noreferrer&quot;&gt;Keating et al.&lt;/a&gt;, 1987, in &lt;em&gt;Seamounts, Islands, and Atolls&lt;/em&gt;, AGU), or by island subsidence due to dissolution.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-04-24T14:03:26.960" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4749" PostTypeId="2" ParentId="4747" CreationDate="2015-04-24T15:49:52.750" Score="11" Body="&lt;p&gt;The average &lt;a href=&quot;https://en.wikipedia.org/wiki/Ecological_footprint&quot; rel=&quot;nofollow&quot;&gt;ecological footprint&lt;/a&gt; of a US citizen has been estimated as &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_countries_by_ecological_footprint&quot; rel=&quot;nofollow&quot;&gt;8.00 global ha&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Multiplying 8.5 million by 8.00 hectare gives 680,000 km², or around 5 times the area of New York &lt;em&gt;state&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, this calculation contains a lot of assumptions and simplifications.  This doesn't mean you could simply allocate 680,000 km² around New York City and use this to support the lifestyle of their inhabitants.  There is a considerable uncertainly around the calculation, and the land is spread all over the world (New Yorkers want their bananas, almonds, and iPhones too, even if none of those are local).&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="725" LastEditDate="2015-04-25T10:47:25.823" LastActivityDate="2015-04-25T10:47:25.823" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4750" PostTypeId="1" AcceptedAnswerId="4751" CreationDate="2015-04-24T16:05:05.197" Score="9" ViewCount="2054" Body="&lt;p&gt;What causes the typical red, pink or orange colors seen in sun-rises and sun-sets?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How come the sky doesn't just turn a darker blue?&lt;/p&gt;&#xA;" OwnerUserId="115" LastActivityDate="2015-09-28T19:37:38.463" Title="What causes the colors seen during a sunset / sunrise?" Tags="|atmosphere|light|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4751" PostTypeId="2" ParentId="4750" CreationDate="2015-04-25T02:35:19.460" Score="9" Body="&lt;p&gt;There are many references about this on the web, such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Sunset&quot;&gt;Wikipedia&lt;/a&gt; and the &lt;a href=&quot;http://www.spc.noaa.gov/publications/corfidi/sunset/&quot;&gt;NOAA&lt;/a&gt; site.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At sunrise and sunset the angle the Sun's light makes with the Earth at those locations is low compared with angle the light makes at midday. Because of the low angle, the light has to travel through more of the atmosphere before it reaches the Earth's surface and the eyes of anyone watching either the Sun rise or the Sun set.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The colour of the Sun's light is white, being composed of the colours of the light spectrum: red, orange, yellow, green, blue, indigo and violet. The &lt;a href=&quot;http://science-edu.larc.nasa.gov/EDDOCS/Wavelengths_for_Colors.html&quot;&gt;wavelength&lt;/a&gt; of these component colours are all different. Red has the longest wavelength at 650 nm. Each of the other colours have shorter wavelengths with violet having the shortest at 400 nm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the Sun's light passes through the atmosphere it get scattered by the air molecules and particles in the air such as dust and aerosols. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Due to a phenomenon known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Rayleigh_scattering&quot;&gt;Rayleigh scattering&lt;/a&gt; the shorter wavelengths of light (greens, blues, violets) are scattered first, leaving the shorter wavelengths (yellows, oranges and reds) to travel further.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The greater the amount of particles in the air, dust and aerosols, the greater the degree of scattering and the more red the sunrises and sunsets will appear. This is particularly evident after large amounts of ash have been ejected by &lt;a href=&quot;http://www.livescience.com/12834-iceland-volcano-fiery-sunsets.html&quot;&gt;volcanoes&lt;/a&gt;, after large forest fires and in locations where &lt;a href=&quot;http://www.economist.com/blogs/babbage/2014/04/air-pollution&quot;&gt;air pollution&lt;/a&gt;, particularly from industrial chimney stacks and internal combustion engines from road vehicles is a major source of airborne &lt;a href=&quot;http://www.scientificamerican.com/article/fact-or-fiction-smog-creates-beautiful-sunsets/&quot;&gt;particulate&lt;/a&gt; matter such as soot or ash and other very small products of combustion&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-04-25T02:35:19.460" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4752" PostTypeId="2" ParentId="4747" CreationDate="2015-04-25T05:13:05.120" Score="4" Body="&lt;p&gt;&lt;strong&gt;City Green Space&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Within New York city, 14% of the city, 29,000 acres (11,735 ha) is &lt;a href=&quot;http://mentalfloss.com/article/55038/25-things-you-might-not-have-known-about-new-york-city&quot; rel=&quot;nofollow noreferrer&quot;&gt;parkland&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Water Supply&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.awra.org/committees/techcom/watershed/pdfs/0203WU.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Management of New York City Water Supply Lands document&lt;/a&gt;, by the New York City Department of Environmental Protection, states the surface water supply system yields 1.3 billion gallons (4.92 GL) of unfiltered drinking water each day to approximately 9 million people.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The watershed that supplies this water occupies 2000 square miles (5178 sq km) spread across 8 counties in upstate New York, it is 73% forested. This is an area twice the size of Rhode Island.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Electricity Supply – If it was 100% Wind Powered&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the &lt;a href=&quot;http://engineering.mit.edu/ask/how-many-wind-turbines-would-it-take-power-all-new-york-city&quot; rel=&quot;nofollow noreferrer&quot;&gt;School of Engineering at MIT&lt;/a&gt;, New York's five boroughs use 60 billion kWh each year. If this were to be supplied by 5 MW wind turbines, 4000 such turbines would be required. An offshore wind farm for 4000, 5 MW turbines, would be 4000 square kilometres, an area 40 miles by 40 miles, which is the equivalent of half of Yellowstone National Park.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Garbage&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;New York city is planning on reducing its &lt;a href=&quot;http://www.ajc.com/ap/ap/top-news/new-york-aims-to-cut-waste-by-90-percent-by-2030/nkzYh/&quot; rel=&quot;nofollow noreferrer&quot;&gt;waste output&lt;/a&gt; by 90%, which is 3 Mt. This means the city is currently producing 3.3 Mt each year (388 kg or 856 lb for each New Yorker). Currently the city's garbage is transported to south Carolina, Virginia, New Jersey, Pennsylvania and upstate New York.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Farmland&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In March 2015, the &lt;a href=&quot;http://www.osc.state.ny.us/reports/importance_agriculture_ny.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;New York State Comptroller&lt;/a&gt; release a report that stated that as of 2012, New York had 35,500 farms covering an area of 7.2 million acres (2.9 million ha)&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-04-25T05:13:05.120" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4753" PostTypeId="1" AcceptedAnswerId="4758" CreationDate="2015-04-25T07:17:02.687" Score="8" ViewCount="722" Body="&lt;p&gt;On the 25th of April at about 11-12pm, an earthquake whose epicenter was in Nepal was felt with a magnitude of 7.5 in Delhi NCR, as well as in other Indian states (Rajasthan, Bihar, Jharkhand, and many more).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What were the reasons behind it?&lt;/p&gt;&#xA;" OwnerUserId="2832" LastEditorUserId="192" LastEditDate="2015-04-25T18:14:33.940" LastActivityDate="2015-04-26T12:56:19.877" Title="Nepal earthquake of 25 April 2015" Tags="|earthquakes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4754" PostTypeId="2" ParentId="4282" CreationDate="2015-04-25T10:46:41.903" Score="2" Body="&lt;p&gt;In my survey of sea ice extent for the same period (1979-2015) I found that the apparent positive trend in dispersed sea ice in the Antarctic in September is anomalous and possibly spurious for two reasons: (1) there was no trend in concentrated sea ice extent or in the degree of sea ice dispersion, and (2) the residuals of the OLS trend line showed patterns that might violate OLS assumptions. Please see &#xA;&lt;a href=&quot;http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2598152&quot; rel=&quot;nofollow&quot;&gt;http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2598152&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2748" LastActivityDate="2015-04-25T10:46:41.903" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4755" PostTypeId="2" ParentId="909" CreationDate="2015-04-25T10:59:14.280" Score="3" Body="&lt;p&gt;I looked at trends in Antarctic sea ice extent in the satellite era from 1979 to 2015 for both the summer minimum (February) and the winter maximum (September) and did not find a statistically significant trend. Please see: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2598152&quot; rel=&quot;nofollow&quot;&gt;http://papers.ssrn.com/sol3/papers.cfm?abstract_id=2598152&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2748" LastActivityDate="2015-04-25T10:59:14.280" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4756" PostTypeId="2" ParentId="4715" CreationDate="2015-04-25T14:14:55.497" Score="5" Body="&lt;p&gt;In meteorology, wind refers to the velocity of air. Its magnitude is called wind speed and has units of m s$^{-1}$. Related quantities are momentum (mass times wind) and kinetic energy (wind times half momentum), but they are &lt;em&gt;not&lt;/em&gt; wind. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Air has mass and thus it has weight as well. Wind does not. &lt;/p&gt;&#xA;" OwnerUserId="192" LastActivityDate="2015-04-25T14:14:55.497" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4757" PostTypeId="2" ParentId="2639" CreationDate="2015-04-26T06:48:29.323" Score="1" Body="&lt;p&gt;At our current rate of global emissions - around 10 billion tonnes per year, PWC's 2013 report estimated that we will exceed the &quot;safe&quot; limit of 2 degrees warming by 2034. Trees planted in tropical areas sequester an average of 22.6 Kg of carbon per annum. NASA estimates that there are currently 400 billion trees globally. The addition of just 7 billion trees (one for every person on Earth) would therefore give us a further 16 years of safe climate at our current rate of emissions. During this time one would hope we will be able to increase renewable energy use, energy efficiency etc so as to reduce our current emissions to sustainable levels. 7 billion is vastly less than the 1,555 billion quoted above and could make all the difference.  &lt;/p&gt;&#xA;" OwnerUserId="2834" LastActivityDate="2015-04-26T06:48:29.323" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4758" PostTypeId="2" ParentId="4753" CreationDate="2015-04-26T12:56:19.877" Score="8" Body="&lt;p&gt;&lt;strong&gt;A brief, very simply explanation.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The earthquake that struck Nepal on 25 April 2015 occurred in a region with a history of catastrophic tremors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Indian tectonic plate is slowly moving at an average rate of 45 mm/year underneath the Eurasian plate. Such movement is never smooth and sometimes the plates get temporarily stuck. Eventually the force producing the movement of the Indian plate increases the pressure on the snagging point, or points, and the plate can jolt. This jolt sends out shock waves through the neighbouring rock which causes the earthquake. The bigger the jolt the stronger the earthquake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;More detail:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the &lt;a href=&quot;http://www.msn.com/en-au/news/world/what-made-deadly-nepal-earthquake-so-catastrophic/ar-BBiGL8E?ocid=mailsignout&quot;&gt;news services&lt;/a&gt; and the &lt;a href=&quot;http://earthquake.usgs.gov/earthquakes/eqinthenews/2011/usc0005wg6/#summary&quot;&gt;US Geological Service&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the USGS wrote in its summary, the quake &quot;occurred as the result of thrust faulting on or near the main frontal thrust between the subducting India plate and the overriding Eurasia plate to the north. At the location of this earthquake, approximately 80 km to the northeast of the Nepalese capital of Katmandu, the India plate is converging with Eurasia at a rate of 45 mm/yr towards the north-northeast, driving the uplift of the Himalayan mountain range. The preliminary location, size and focal mechanism of the April 25 earthquake are consistent with its occurrence on the main subduction thrust interface between the India and Eurasia plates.&quot;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;According to the USGS, a quake in the region in 1934 is believed to have killed roughly 10,600 people. Another in 1988 killed 1,500.&#xA;  But the experts said big quakes in the area are not necessary common.&#xA;  &quot;Although a major plate boundary with a history of large-to-great sized earthquakes, large earthquakes on the Himalayan thrust are rare in the documented historical era,&quot; the UGS wrote. &quot;Just four events of magnitude 6 or larger have occurred ... over the past century.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-04-26T12:56:19.877" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4759" PostTypeId="2" ParentId="400" CreationDate="2015-04-26T18:36:14.627" Score="5" Body="&lt;p&gt;There are two books I love to recommend on this. &lt;a href=&quot;https://www.google.com/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=2&amp;amp;cad=rja&amp;amp;uact=8&amp;amp;ved=0CCcQFjAB&amp;amp;url=http%3A%2F%2Fen.wikipedia.org%2Fwiki%2FThe_Worst_Hard_Time&amp;amp;ei=DS89VbPmE8qsogSjhYD4BA&amp;amp;usg=AFQjCNHaJygdo0JduwPygm0HEWkp4AFXog&amp;amp;sig2=72s0snV5i0o8t8ZmoH08Rw&amp;amp;bvm=bv.91665533,d.cGU&quot; rel=&quot;nofollow&quot;&gt;The Worst Hard Time&lt;/a&gt; is a history book with a lot of first-person reports and a summary of what people were thinking &lt;em&gt;before&lt;/em&gt; the dust bowl -- what the optimism looked like. The saddest bit I remember was that there were responsible ranchers who didn't over-plow, who had intact prairie -- until their neighbor's dust buried them and killed their grass and herds. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other is on huger scale, &lt;a href=&quot;http://www.ucpress.edu/book.php?isbn=9780520272903&quot; rel=&quot;nofollow&quot;&gt;Dirt: The Erosion of Civilizations&lt;/a&gt;. Big erosive events are recorded in sediment fans (often in the ocean at river-mouths). Analyzing these, Montgomery argues that there have been six cases of organization-&gt;ag-&gt;regional market-&gt;over-farming-&gt;erosion-&gt;collapse, and that we're plausibly in the seventh. &lt;/p&gt;&#xA;" OwnerUserId="2639" LastEditorUserId="2639" LastEditDate="2015-04-30T07:04:22.227" LastActivityDate="2015-04-30T07:04:22.227" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4760" PostTypeId="1" AcceptedAnswerId="4761" CreationDate="2015-04-26T22:01:48.450" Score="7" ViewCount="913" Body="&lt;p&gt;The question is basically: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;During the Cretaceous there were no continental    ice    sheets. The ratio&#xA;  of O-18/O-16 in sea water was:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;a) Higher than today&lt;br&gt;&#xA;  b) Lower than today&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The answer is stated to be b, but it does not make sense as glaciers have a lower &lt;sup&gt;18&lt;/sup&gt;O/&lt;sup&gt;16&lt;/sup&gt;O ratio and so the ratio should be higher than today. Can someone justify why it's b?&lt;/p&gt;&#xA;" OwnerUserId="2659" LastEditorUserId="11908" LastEditDate="2019-03-13T05:01:09.753" LastActivityDate="2019-03-13T05:01:09.753" Title="Oxygen isotope ratio and Glaciers" Tags="|oceanography|geochemistry|homework|glaciology|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4761" PostTypeId="2" ParentId="4760" CreationDate="2015-04-26T22:44:52.937" Score="7" Body="&lt;p&gt;It does make sense.&#xA;As you said - glaciers have lower &lt;sup&gt;18&lt;/sup&gt;O/&lt;sup&gt;16&lt;/sup&gt;O. This is because they have less &lt;sup&gt;18&lt;/sup&gt;O overall. Therefore, the oceans have more &lt;sup&gt;18&lt;/sup&gt;O. But this is today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the Cretaceous there were no continental ice sheets, so what we said previously is not relevant. There are no ice sheets to take all of the &lt;sup&gt;16&lt;/sup&gt;O, so it's all in the ocean. This results in a lower overall &lt;sup&gt;18&lt;/sup&gt;O/&lt;sup&gt;16&lt;/sup&gt;O ratio.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-04-26T22:44:52.937" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4762" PostTypeId="1" CreationDate="2015-04-27T00:57:32.473" Score="4" ViewCount="1068" Body="&lt;p&gt;I know that a parcel of air can rise, cool and create clouds and rain but I'm struggling to understand how:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;absolute humidity&lt;/li&gt;&#xA;&lt;li&gt;relative humidity&lt;/li&gt;&#xA;&lt;li&gt;actual vapour pressure&lt;/li&gt;&#xA;&lt;li&gt;saturation vapour pressure&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;change as a parcel of air with an unchanging amount of water vapour rises, expands and cools.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think that absolute humidity and relative humidity increase, but is there a difference how absolute and relative humidity behave and how actual vapour pressure and saturation vapour pressure behave?&lt;/p&gt;&#xA;" OwnerUserId="2841" LastEditorUserId="725" LastEditDate="2016-09-13T12:45:47.440" LastActivityDate="2016-09-13T12:45:47.440" Title="How and why humidity and vapour pressure change as a parcel of air with an unchanging amount of water vapor rises, expands, and cools" Tags="|meteorology|atmosphere|homework|humidity|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4763" PostTypeId="2" ParentId="4760" CreationDate="2015-04-27T01:23:59.983" Score="6" Body="&lt;p&gt;There is a &lt;a href=&quot;http://www.sciencemag.org/content/310/5752/1293&quot; rel=&quot;nofollow noreferrer&quot;&gt;quite relevant paper&lt;/a&gt; in &lt;em&gt;Science&lt;/em&gt; with a fine analysis and interpretation on $\delta$ &lt;sup&gt;18&lt;/sup&gt;O evolution during the &lt;a href=&quot;http://stratigraphy.org/ICSchart/ChronostratChart2015-01.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Phanerozoic Eon&lt;/a&gt;, which quite summarily display how this ratio depend on the sea level among other things.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Full reference here : &#xA;Miller, K. G.; Kominz, M. A.; Browning, J. V.; Wright, J. D.; Mountain, G. S.; Katz, M. E.; Sugarman, P. J.; Cramer, B. S.; Christie-Blick, N. &amp;amp; Pekar, S. F. The Phanerozoic Record of Global Sea-Level Change Science, 2005, 310, 1293-1298&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Actually, following this paper, sea level was somewhat higher than today during the late Cretaceous, with a 100 $\pm$ 50 m peak during that period (in the abstract). They established the concept of &lt;em&gt;a small and ephemeral ice sheet&lt;/em&gt; in Antarctica as well between 100 and 33 Million years. Some significant factors regulating the sea level and oxygen ratios would be, for any given time:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Sea Level&lt;/li&gt;&#xA;&lt;li&gt;Average global temperature&lt;/li&gt;&#xA;&lt;li&gt;Tectonic activity and related tectonoeustasy &gt; implying impact on water displacement&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Briefly to answer the question, Figure 3 in the paper show the $\delta$ &lt;sup&gt;18&lt;/sup&gt;O in all time during the Cretaceous as lower than during recent times - so b) is the answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/wdYKm.png&quot; alt=&quot;Re-plot of Miller et al. 2005 Figure 3 showing oxygen isotopes and sea level change since 100Ma&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Redrawn and simplified after Miller et al. 2005&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="1411" LastEditorUserId="87" LastEditDate="2015-04-27T06:41:18.653" LastActivityDate="2015-04-27T06:41:18.653" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4764" PostTypeId="2" ParentId="4715" CreationDate="2015-04-27T01:44:37.447" Score="2" Body="&lt;p&gt;There's no need to get into details about the energy in wind:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's assume there is wind in a volume of air.&lt;br&gt;&#xA;Now, the wind stops.&lt;br&gt;&#xA;The mass of the air in the volume did not change&lt;sup&gt;*&lt;/sup&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the mass of air plus the mass of wind is the same as the mass of air. Therefore, the mass of wind must be 0:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;m&lt;sub&gt;air&lt;/sub&gt; + m&lt;sub&gt;wind&lt;/sub&gt; = m&lt;sub&gt;air&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;m&lt;sub&gt;wind&lt;/sub&gt; = 0&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;&lt;br&gt;&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;*) Assuming the volume is large enough that the effects on the border of the volume are relatively small enough.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="321" LastActivityDate="2015-04-27T01:44:37.447" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4765" PostTypeId="2" ParentId="4762" CreationDate="2015-04-27T10:50:37.407" Score="3" Body="&lt;p&gt;The imortant point is that absolute humidity is defined as&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;mass of water&lt;/strong&gt; per &lt;strong&gt;volume of air&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if the parcel of air expands, and still has the same water content, there is less mass of water per volume, hence the absolute humidity decreases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe most if not all of the question depends on this and is much more clear now?  &lt;/p&gt;&#xA;" OwnerUserId="321" LastActivityDate="2015-04-27T10:50:37.407" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="4766" PostTypeId="1" CreationDate="2015-04-27T16:26:11.917" Score="2" ViewCount="178" Body="&lt;p&gt;For a biology research project I have to look for the estimated amount of plant and animal species in the ocean. After hours of searching, I came here to ask for help. I need both of these questions answered. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;How many plant species are present in the ocean?&lt;/li&gt;&#xA;&lt;li&gt;How many animal species are present in the ocean?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="2845" LastEditorUserId="192" LastEditDate="2015-04-27T16:46:55.420" LastActivityDate="2015-04-27T16:46:55.420" Title="How many plant species and animal species are there in the ocean?" Tags="|ocean|" AnswerCount="0" CommentCount="2" ClosedDate="2015-04-27T19:21:57.643" ContentLicense="CC BY-SA 3.0" />
  <row Id="4767" PostTypeId="1" AcceptedAnswerId="4774" CreationDate="2015-04-27T16:47:04.270" Score="8" ViewCount="810" Body="&lt;p&gt;Wikipedia provides a &lt;a href=&quot;http://en.wikipedia.org/wiki/List_of_deadly_earthquakes_since_1900&quot;&gt;list of deadly earthquakes since 1900&lt;/a&gt;. Where would the April 2015 &lt;a href=&quot;http://en.wikipedia.org/wiki/2015_Nepal_earthquake&quot;&gt;Nepal earthquake&lt;/a&gt; (magnitude currently estimated as 7.8 or 8.1) rank in this list, in terms of magnitude?&lt;/p&gt;&#xA;" OwnerDisplayName="user2846" LastEditorUserId="111" LastEditDate="2016-12-18T21:16:05.170" LastActivityDate="2016-12-18T21:16:05.170" Title="Where does the 2015 Nepal earthquake rank amongst earthquakes since 1900?" Tags="|seismology|earthquakes|seismic-hazards|history|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4769" PostTypeId="1" AcceptedAnswerId="4771" CreationDate="2015-04-27T23:12:15.997" Score="14" ViewCount="2007" Body="&lt;p&gt;My daughter has a writing assignment based on a handout about plate tectonics. One paragraph says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Molten rock from the earth's mantle pushes up through the surface at the mid-Atlanic ridge. The rock cools and forms new sections of crust on the ocean floor. The ocean floor has to make room for the new crust. To make enough room, the ocean floor must spread out. As a result, the earth's plates shift.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It's been a long time since &lt;em&gt;I&lt;/em&gt; was in school and this is far from my field, but this doesn't sound right to me. Isn't the main cause convection currents in the earth's mantle? Is cooling lava pushing the plates apart a &lt;em&gt;cause&lt;/em&gt;? I thought it was basically an &lt;em&gt;effect&lt;/em&gt; — where the plates diverge, molten rock pushes up and fills in. (Or, is this just two ways of looking at the same thing?)&lt;/p&gt;&#xA;" OwnerUserId="1214" LastEditorUserId="111" LastEditDate="2015-07-07T18:12:44.540" LastActivityDate="2020-04-21T05:29:06.003" Title="Is continental drift caused by lava pushing the seabed apart?" Tags="|plate-tectonics|sea-floor-spreading|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4770" PostTypeId="2" ParentId="4742" CreationDate="2015-04-27T23:34:39.067" Score="9" Body="&lt;p&gt;&lt;strong&gt;Book:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shyy W, Udaykumar HS, Rao MM, Smith RW. Computational Fluid Dynamics with Moving Boundaries. Taylor&amp;amp; Francis: London, 1996.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Some relevant papers:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Jin C, Xu K. A unified moving grid gas-kinetic method in Eulerian space for viscous flow comnputation. Journal of Computational Physics 2007; 222:155–175.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hirt CW, Amsden AA, Cook JL. An arbitrary Lagrangian–Eulerian computing method for all flow speeds. Journal of Computational Physics 1997; 135:203–216.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Piggott M, Pain C, Gorman G, Power P, Goddard A. h, r, and hr adaptivity with applications in numerical ocean modeling. Ocean Modelling 2005; 10:95–113&lt;/p&gt;&#xA;&#xA;&lt;p&gt;HuangWZ, Ren Y, Russell RD.Moving mesh methods based on moving mesh partial differential equations. Journal of Computational Physics 1994; 113:279–290.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Miller K, Miller RN. Moving finite element. SIAM Journal of Numerical Analysis 1981; 18:1019–1032.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Dorfi EA, Drury LO. Simple adaptive grids for 1-D initial value problems. Journal of Computational Physics 1987; 69:175–195.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tang T. Moving mesh methods for computational fluid dynamics. Contemporary Mathematics 2005; 383:141–174.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tang H, Tang T. Adaptive mesh methods for one- and two-dimensional hyperbolic conservation laws. SIAM Journal of Numerical Analysis 2003; 41(2):487–515.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tang H, Tang T. Multi-dimensional moving mesh method for shock computations. Contemporary Mathematics 2003; 330:169–183.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Adaptive grid concepts have been applied to the &lt;a href=&quot;http://www.ccpo.odu.edu/POMWEB/&quot;&gt;Princeton Ocean Model (POM)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Original Paper for POM:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.stevens-tech.edu/ses/ceoe/fileadmin/ceoe/pdf/alan_publications/AFB032.pdf&quot;&gt;Blumberg, A. F. and G. L. Mellor, A description of a three-dimensional coastal ocean circulation model. Three-Dimensional Coastal ocean Models, edited by N. Heaps, 208 pp., American Geophysical Union., 1987&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;With adaptive mesh:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S1463500309002248&quot;&gt;Hofmeister, Richard, Hans Burchard, and Jean-Marie Beckers. &quot;Non-uniform adaptive vertical grids for 3D numerical ocean models.&quot; Ocean Modelling 33.1 (2010): 70-86.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2015-04-28T17:44:29.937" LastActivityDate="2015-04-28T17:44:29.937" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4771" PostTypeId="2" ParentId="4769" CreationDate="2015-04-28T01:03:29.717" Score="16" Body="&lt;p&gt;&lt;strong&gt;No, lava does not push the plates apart.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mid-ocean ridge basalt is passively filling the space left by the plates moving apart. Plate motion is driven by gravity (image by Vic DiVenere at Columbia; see note below):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/qpaJX.gif&quot; alt=&quot;Forces driving plate tectonics&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are thought to be two main effects at play: &lt;a href=&quot;https://en.wikipedia.org/wiki/Ridge_push&quot; rel=&quot;noreferrer&quot;&gt;ridge push&lt;/a&gt;, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Slab_pull&quot; rel=&quot;noreferrer&quot;&gt;slab pull&lt;/a&gt;. We don't know much about their relative importance, but it probably varies spatially (e.g. Ribeiro, 2012, &lt;em&gt;Soft Plate and Impact Tectonics&lt;/em&gt;, Springer).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Ridge push&lt;/strong&gt; happens not because the new lava is pushing, but because the ridge is high up. It's so high that in some places it sticks out of the water (e.g. Iceland). It's high because it's hot — but not from deep convection. A geophysical technique called &lt;a href=&quot;https://en.wikipedia.org/wiki/Seismic_tomography&quot; rel=&quot;noreferrer&quot;&gt;seismic tomography&lt;/a&gt; suggests that the hot zone is relatively shallow. As the new plate cools, it thickens and sinks 'downhill', pushing the older plate ahead.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Slab pull&lt;/strong&gt; is easier to imagine: a subducting plate, sinking into the asthenosphere (uppermost mantle), pulls the younger plate behind it. Not all margins are destructive, however, so slab pull does not operate everywhere. Indeed, the relative important of push and pull is debated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You will sometimes see figures like &lt;a href=&quot;https://en.wikipedia.org/wiki/Mid-ocean_ridge#/media/File:Oceanic_spreading.svg&quot; rel=&quot;noreferrer&quot;&gt;this one&lt;/a&gt;, strongly implying that convection and plate motion are strongly coupled. The earth is a complex system so the processes are certainly related, but we don't understand the frictional forces (drag) at the lithosphere–asthenosphere boundary well (e.g. &lt;a href=&quot;http://www.columbia.edu/~vjd1/driving_forces_basic.htm&quot; rel=&quot;noreferrer&quot;&gt;read this primer&lt;/a&gt; by DiVenere). These images, while prevalent, are an unhelpful over-simplification. &lt;/p&gt;&#xA;&#xA;&lt;hr /&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Note:&lt;/em&gt; I'm using DiVenere's copyrighted image under 'fair use' terms. Please replace it with an open version if you find one! (But not one with convection cells :)&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-04-28T01:03:29.717" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4772" PostTypeId="1" AcceptedAnswerId="4773" CreationDate="2015-04-28T06:56:36.997" Score="7" ViewCount="280" Body="&lt;p&gt;It is said that before an earthquake happens, a viewer experiences disturbances in DTH TV transmission in the form of distorted images on the screen which automatically correct after a few seconds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it possible to identify patterns of such disturbances by continuously monitoring TV images so that earthquakes can potentially be predicted at least few minutes in advance and many lives could be saved?&lt;/p&gt;&#xA;" OwnerUserId="2850" LastEditorUserId="2536" LastEditDate="2015-04-28T08:26:47.680" LastActivityDate="2015-05-27T19:44:10.280" Title="Predicting earthquakes using disturbances in DTH TV transmission" Tags="|geophysics|earthquakes|geodynamics|remote-sensing|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4773" PostTypeId="2" ParentId="4772" CreationDate="2015-04-28T08:28:52.170" Score="7" Body="&lt;p&gt;Earthquake prediction &lt;a href=&quot;https://earthscience.stackexchange.com/questions/878/is-earthquake-prediction-possible?rq=1&quot;&gt;have been discussed before in this forum&lt;/a&gt; and is rather dispiriting. Distortion in transmitted signals could be an early indication of earthquake, but seismometers (geophones) are still a far better instrument to detect vibrations. In future &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/grl.50205/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;satellites&lt;/a&gt; could be an option in remote areas. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, damage from an earthquake can be mitigated if warning signals can be transmitted to reach people before the actual arrival of the most devastating surface waves. It helps, in this context, that the surface waves that are  relatively slow. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Early warning systems are used in e.g &lt;a href=&quot;http://en.wikipedia.org/wiki/Earthquake_Early_Warning_%28Japan%29&quot; rel=&quot;nofollow noreferrer&quot;&gt;Japan&lt;/a&gt; to slow down trains and automatically alert people through radio and internet. Similar systems are used and developed in &lt;a href=&quot;http://internationalscienceindex.org/publications/10327/bayesian-networks-for-earthquake-magnitude-classification-in-a-early-warning-system/&quot; rel=&quot;nofollow noreferrer&quot;&gt;other&lt;/a&gt; earthquake affected regions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The challenge is that such systems are expensive and moreover, people with limited access to radio and other sources of information might not be able to receive the warnings. The problem is similar to the &lt;a href=&quot;http://www.tsunami.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tsunami warnings&lt;/a&gt;, that the &lt;a href=&quot;http://www.21stcenturychallenges.org/focus/who-are-most-vulnearable-to-natural-hazards/&quot; rel=&quot;nofollow noreferrer&quot;&gt;most vulnerable people&lt;/a&gt; are the those receiving least help.&lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-04-28T10:16:45.397" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4774" PostTypeId="2" ParentId="4767" CreationDate="2015-04-28T14:45:42.320" Score="8" Body="&lt;p&gt;&lt;strong&gt;About 80th.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I counted the earthquakes of each magnitude on the &lt;a href=&quot;http://en.wikipedia.org/wiki/List_of_deadly_earthquakes_since_1900&quot; rel=&quot;nofollow noreferrer&quot;&gt;List of deadly earthquakes...&lt;/a&gt; article. If the Nepal earthquake is about M7.8, then it's in the range 69th to 86th on that list:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/i5iQ5.png&quot; alt=&quot;Table of deadly earthquakes&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that &lt;a href=&quot;http://en.wikipedia.org/wiki/Lists_of_earthquakes&quot; rel=&quot;nofollow noreferrer&quot;&gt;there are more earthquakes than this&lt;/a&gt; in recent history, the list has already selected for deadliness. Also note the point in the comments about different magnitude measures in the list, and the fact that the list is a few years out of date. I don't think these things change the answer.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2015-04-29T02:15:23.997" LastActivityDate="2015-04-29T02:15:23.997" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="4775" PostTypeId="1" CreationDate="2015-04-28T19:10:19.333" Score="4" ViewCount="900" Body="&lt;p&gt;I am trying to determine what could cause periodic flooding of the type that might generate a savannah or plain with low growing plants and grasses. Where does the water come from, and how or why is it consistently periodic? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This question refers to no specific area. It is asked with a worldbuilding mindset, and I'm just trying to figure out how periodic flooding works in general. &lt;/p&gt;&#xA;" OwnerUserId="2848" LastEditorUserId="725" LastEditDate="2016-09-13T12:43:17.783" LastActivityDate="2016-09-13T12:43:17.783" Title="What causes periodic floods?" Tags="|flooding|world-building|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4776" PostTypeId="2" ParentId="4775" CreationDate="2015-04-29T00:02:49.053" Score="6" Body="&lt;p&gt;The causes vary around the world, but we can make some generalizations. Seasonal floods mean that there's more water coming in than going out for only &lt;em&gt;part&lt;/em&gt; of the year. If it's annual, the changes are probably related to annual weather patterns in precipitation, temperature, or both. Some big sub-cases are: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(a) in Mediterranean climates, e.g. California, almost all the rain falls in winter in cool weather when evapotranspiration is relatively low. The Central Valley has regions that develop standing water from the rain that falls directly on them because the soil has impermeable clay or hardpan (the vernal pools prairies); and other regions that develop standing water because they're the confluence of several drainages and in wet years the water literally can't flow out to the sea as fast as it comes in (the Yolo Bypass). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(b) If annual precipitation includes a lot of snow and it melts in a hurry, it's common for the downstream rivers to flood at the confluences. There may be years in which the surface snow is melted while the ground is still impermeably frozen, which would turn anyplace level swampy. Parts of Minnesota have bedrock not far under the soil surface and they get this kind of inundation relatively easily. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(c) Where rivers meet the ocean in a long, nearly level bench, high tide (spring tide or storm tide especially) can raise the river level enough that the fields flood. I believe this is the case in the Somerset Levels and in the Netherlands. Some of these are watermeadows and can be quite productive if farmed carefully. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These don't all develop the same kinds of vegetation. For instance, I think I've forgotten a tropical or semitropical case where monsoon rains overwhelm the drainage (possibly the entire Amazon, where the hardwoods are adapted to having their roots underwater even though they aren't flooded all year). &lt;/p&gt;&#xA;" OwnerUserId="2639" LastActivityDate="2015-04-29T00:02:49.053" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4777" PostTypeId="2" ParentId="4769" CreationDate="2015-04-29T02:52:23.617" Score="6" Body="&lt;p&gt;To add to a already complete answer by kwinkunks, perhaps one of the most surprising things about plate tectonics to geophysicists was the fact that in some cases extension in the lithosphere (rifting) is a direct cause of subduction zones. When the idea of subduction zones was finally formalized (~1969) most geophysicists expected &lt;em&gt;all&lt;/em&gt; subduction zones to be accompanied by an area of compression, but what is later found is that rifting centers opened up nearby. What studies further found is that the motion of the upper plate and the viscous coupling of the subducting plate caused the trench to roll backwards in the opposite direction of subudciton! This trench rollback opens ups an oceanic ridge, what we call back-arc spreading centers! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the whole point of this small digression is that plate tectonics is a very complex issue, and not all the forces are well understood. Models show that the mantle is convecting near plate margins at orders of magnitude greater than plate motion. Inside the mantle wedge of subduction zones we see rapid and complex mantle flows that react to plate geometry in unpredictable ways. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Melting (lava/magama) certainly plays a apart in our plate motions, but we really have no idea how much it does. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To be honest, if we did, a lot of geophysicists would be looking to do something else. &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2015-04-29T02:52:23.617" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4778" PostTypeId="1" AcceptedAnswerId="4779" CreationDate="2015-04-29T05:03:41.747" Score="6" ViewCount="27181" Body="&lt;p&gt;I want to know if large earthquakes can happen twice in the same region?&#xA;The reason is that the recent earthquake in Nepal was followed by many after shocks of considerable magnitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I wanted to know if there are chances of earthquake of this magnitude in the same region again.&#xA;Can we expect another earthquake in the same region, lets say in a month or few months?&lt;/p&gt;&#xA;" OwnerUserId="2856" LastEditorUserId="725" LastEditDate="2016-09-10T09:17:08.707" LastActivityDate="2016-09-12T12:31:50.007" Title="Can large earthquakes happen twice/thrice at the same place within a short timeframe" Tags="|seismology|earthquakes|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4779" PostTypeId="2" ParentId="4778" CreationDate="2015-04-29T13:20:37.287" Score="6" Body="&lt;p&gt;Aftershocks after a major earthquake can occur for a period of weeks after the initial major earthquake, but the magnitude of the aftershocks is always less than that of the initial major quake. The paper &lt;a href=&quot;http://r.duckduckgo.com/l/?kh=-1&amp;amp;uddg=http%3A%2F%2Fwww.annalsofgeophysics.eu%2Findex.php%2Fannals%2Farticle%2Fdownload%2F3338%2F3384&quot;&gt;History of Earthquakes of India &amp;amp; the Himalayas&lt;/a&gt; discusses the each of the major earthquakes in the region for the last 200 years. Information on earthquakes before 1800 is patchy. The earthquakes discussed are the ones that occurred in: 1803, 1833, 1869, 1897 &amp;amp; 1905.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nothing was mentioned about a second or third major earthquake happening shortly after a major earthquake; even for the devastating &lt;a href=&quot;https://en.wikipedia.org/wiki/1934_Nepal%E2%80%93Bihar_earthquake&quot;&gt;1934 earthquake&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Due to the different tectonic settings and causes for earthquakes in different parts of the world it is best not to look at the history of one part of the world and assume the same will occur elsewhere. The expectancy of earthquakes and their patterns in the Himalayas should not be compared with earthquakes in Japan, New Zealand, western USA, Turkey or elsewhere.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-04-29T13:20:37.287" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4781" PostTypeId="1" CreationDate="2015-04-29T16:11:50.910" Score="10" ViewCount="257" Body="&lt;p&gt;Climate change has the potential to increase flooding by &lt;a href=&quot;http://dx.doi.org/10.1073/pnas.1209542109&quot;&gt;hurricane intensification&lt;/a&gt; (magnitude and intensity) and by sea level rise. Many communities around the world are already exposed to coastal flooding from tropical cyclones. How much will the changes associated with climate change enhanced coastal flooding? I know this is largely region specific, but I would like to know of studies that quantify these effects.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2016-06-11T03:58:28.293" Title="What is the potential impact of hurricane intensification and sea level rise on coastal flooding?" Tags="|climate-change|sea-level|tropical-cyclone|flooding|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4782" PostTypeId="1" AcceptedAnswerId="4783" CreationDate="2015-04-29T17:48:17.507" Score="11" ViewCount="1501" Body="&lt;p&gt;I'm having a slightly difficult time understanding the Keeling curve, pictured here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/3LTgu.jpg&quot; alt=&quot;Atmospheric carbon dioxide&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand that carbon dioxide (ppm) is increasing with respect to time, but why is there an oscillation between the summer months and winter months? I have two guesses but I'm not sure if they are correct:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Changes in density due to temperature?&lt;/li&gt;&#xA;&lt;li&gt;More plants in the summer, resulting in less carbon.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Are these guesses correct? &lt;/p&gt;&#xA;" OwnerUserId="2604" LastEditorUserId="28050" LastEditDate="2015-06-05T15:15:50.413" LastActivityDate="2015-06-05T15:15:50.413" Title="Oscillations in the Keeling curve?" Tags="|climate-change|temperature|carbon|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4783" PostTypeId="2" ParentId="4782" CreationDate="2015-04-29T19:45:17.763" Score="14" Body="&lt;p&gt;Photosynthesis increase in the northern hemisphere spring, especially in the Siberian Taiga, and carbon dioxide decrease in atmosphere. During autumn and winter, decomposition of plant material and increased combustion, bring more carbon dioxide to the atmosphere. Measurements from e.g. the South Pole shows the same pattern, but much less and in opposite phase.  As the &lt;a href=&quot;http://en.wikipedia.org/wiki/Temperate_forest&quot;&gt;temperate&lt;/a&gt; and boreal landmass are larger on the northern hemisphere, the oscillation is also larger.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's well explained &lt;a href=&quot;http://dougrobbins.blogspot.dk/2012/03/keeling-curve-and-seasonal-carbon.html&quot;&gt;here&lt;/a&gt;. Also check &lt;a href=&quot;http://www.esrl.noaa.gov/gmd/dv/iadv/&quot;&gt;ESRL&lt;/a&gt; and &lt;a href=&quot;http://cdiac.ornl.gov/&quot;&gt;CDIAC&lt;/a&gt; for more stations and downloadable data sets. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2015-04-30T07:19:07.803" LastActivityDate="2015-04-30T07:19:07.803" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4785" PostTypeId="1" CreationDate="2015-04-30T06:09:56.043" Score="2" ViewCount="149" Body="&lt;p&gt;In the WAM Cycle 4 wave model, why doesn't the model work for the year 1999? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I tried to run for the year 1999 the model does not produce any results.&lt;/p&gt;&#xA;" OwnerUserId="2859" LastEditorUserId="725" LastEditDate="2016-09-13T12:41:11.560" LastActivityDate="2016-09-13T12:41:11.560" Title="Problem running the WAM wave model" Tags="|ocean|models|waves|numerical-modelling|software|" AnswerCount="0" CommentCount="3" ClosedDate="2016-12-06T08:32:42.213" ContentLicense="CC BY-SA 3.0" />
  <row Id="4786" PostTypeId="2" ParentId="400" CreationDate="2015-04-30T09:03:52.553" Score="4" Body="&lt;p&gt;&lt;a href=&quot;http://hthttp://weather.about.com/od/weatherfaqs/f/dustbowl.htmtp://&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate modelling&lt;/a&gt; by NASA suggests a change in the Jet Stream was partially responsible for the 1930s drought in the US.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Cooler than normal tropical Pacific Ocean temperatures and warmer than normal tropical Atlantic Ocean temperatures created ideal drought conditions due to the unstable sea surface temperatures. The result was dry air and high temperatures in the Midwest from about 1931 to 1939.&lt;/p&gt;&#xA;&lt;p&gt;Sea surface temperatures create shifts in weather patterns. One way is by changing the patterns in the jet stream. In the 1930's, the jet stream was weakened causing the normally moisture rich air from the Gulf of Mexico to become drier. Low level winds further reduced the normal supply of moisture from the Gulf of Mexico and reduced rainfall throughout the US Midwest.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://o9.com/study-reveals-the-dust-bowl-was-the-worst-drought-in-1-1646560925&quot; rel=&quot;nofollow noreferrer&quot;&gt;Other conditions&lt;/a&gt; at the time included:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;a high-pressure system in winter sat over the west coast of the United States and turned away wet weather— a pattern similar to that which occurred in the winter of 2013-14. Second, the spring of 1934 saw dust storms, caused by poor land management practices, suppress rainfall.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-04-30T09:11:04.773" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4787" PostTypeId="1" AcceptedAnswerId="4801" CreationDate="2015-05-01T15:12:18.140" Score="8" ViewCount="1256" Body="&lt;p&gt;On a trip to Brighton, England on April 12th, 2015, I noticed this strange plume in the sky over the English Channel at about 13:00 hours. It looks like;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Something that fell out of the sky - the news and other chatter over the following days revealed nothing which would support that.&lt;/li&gt;&#xA;&lt;li&gt;A tornado/wind vortex drawing water up from the surface?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/0Mzme.jpg&quot; alt=&quot;Cloud Plume&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please note, I took this photo with my phone, with the window down and it is completely unedited. Is this a meteorological phenomenon, and if so, what is it?&lt;/p&gt;&#xA;" OwnerUserId="2862" LastEditorUserId="725" LastEditDate="2018-06-09T01:29:05.530" LastActivityDate="2018-06-09T01:29:05.530" Title="What atmospheric phenomenon am I seeing in this photo?" Tags="|atmosphere|clouds|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="4788" PostTypeId="1" CreationDate="2015-05-01T18:00:00.943" Score="10" ViewCount="7933" Body="&lt;p&gt;While asking questions on &lt;a href=&quot;https://worldbuilding.stackexchange.com/&quot;&gt;Worldbuilding&lt;/a&gt;, I keep hearing about wet/dry seasons. Obviously, one has rain and the other doesn't, and I've gathered that they occur with regularity on an annual basis, but what exactly are they? What causes them, and when/how often do they form? &lt;/p&gt;&#xA;" OwnerUserId="2848" LastEditorUserId="-1" LastEditDate="2017-04-13T12:52:35.360" LastActivityDate="2018-01-20T05:39:58.623" Title="Wet and dry seasons - what are they and how do they form?" Tags="|meteorology|climate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4789" PostTypeId="1" AcceptedAnswerId="4790" CreationDate="2015-05-01T18:05:45.150" Score="7" ViewCount="2588" Body="&lt;p&gt;Has there ever been a movie, a documentary, or an image that provides a visualization of the oceans without water? I'm writing an article on geology and I thought a visual representation would be of great importance. Any help is appreciated.&lt;/p&gt;&#xA;" OwnerDisplayName="user2846" LastEditorUserId="94" LastEditDate="2015-05-02T13:09:50.203" LastActivityDate="2020-11-08T13:34:39.700" Title="How would the Earth look without water in the oceans?" Tags="|ocean|water|earth-observation|visualization|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4790" PostTypeId="2" ParentId="4789" CreationDate="2015-05-02T01:06:18.077" Score="4" Body="&lt;p&gt;National Geographic made a documentary called &lt;strong&gt;Drain the Ocean&lt;/strong&gt;, this is &lt;a href=&quot;https://www.youtube.com/watch?v=HVJNLSwCGHc&quot; rel=&quot;noreferrer&quot;&gt;You Tube link to part one&lt;/a&gt;. the other three parts are there as well.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-05-02T01:06:18.077" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4792" PostTypeId="1" AcceptedAnswerId="4795" CreationDate="2015-05-02T22:28:40.697" Score="10" ViewCount="6117" Body="&lt;p&gt;&lt;a href=&quot;http://www.cesm.ucar.edu/experiments/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Community Earth System Model&lt;/a&gt; (CESM) is described as a &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;fully-coupled, global climate model that provides state-of-the-art&#xA;  computer simulations of the Earth's past, present, and future climate&#xA;  states&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I've come across &quot;coupling&quot; and &quot;coupled model&quot; many times but still have trouble with the term. What does &quot;coupling&quot; and &quot;fully coupled&quot; mean? Does refer to the physics or numerical aspects?&lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorUserId="725" LastEditDate="2016-11-26T11:57:29.787" LastActivityDate="2016-11-26T11:57:29.787" Title="Meaning of Coupling in Modelling" Tags="|models|numerical-modelling|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4793" PostTypeId="2" ParentId="4792" CreationDate="2015-05-03T01:55:38.703" Score="4" Body="&lt;p&gt;Coupling is used in the context of feedback between various processes. It can be weak or strong. E.g, if you heat a rod it expands mechanically due to thermoelastic effects (strong coupling) but when you mechanically compress it the temperature rise is insignificant (weak coupling). On the other hand for a poroelastic material the coupling is strong both ways. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In climate/weather codes the term is used at a rather higher level, i.e., coupling between atmospheric, land and oceanic processes. It does refers to physics but it also has numerical implications.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastActivityDate="2015-05-03T01:55:38.703" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4794" PostTypeId="2" ParentId="4792" CreationDate="2015-05-03T02:05:16.053" Score="7" Body="&lt;p&gt;Coupling refers to communication and interchange of information between models.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example a typical standalone atmospheric model may be initialized with information about sea surface temperature.  Depending on the model the ocean may be treated as a heat reservoir and may or may not affect any change to the SST.  The ocean itself is not modeled.  Similarly an ocean model may parameterize the atmosphere and only care about surface temperature and moisture fluxes (and perhaps momentum fluxes for waves) which may be static or prescribed values.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Contrast this to a coupled model where the atmosphere and ocean models exchange data with each other so that they can evolve as a whole.  Rather than the atmosphere seeing a static SST, it sees the modeled SST from the ocean model.  Because the ocean is modeled even more information than just SST is available to the atmosphere model.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;CESM in particular is a family of models that all talk to each other to model earth, air and water as a whole system.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-05-03T02:05:16.053" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4795" PostTypeId="2" ParentId="4792" CreationDate="2015-05-03T02:07:13.517" Score="8" Body="&lt;p&gt;In Earth-system models, the term &quot;coupling&quot; is often used in two ways.  The first is &quot;offline&quot; coupling, where output from one model is passed to another model for computation of some variable.  The second is &quot;online&quot; coupling, where the feedbacks are allowed to pass between the two models.  Online coupling is synonymous with &quot;fully coupled&quot;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good example is when wildfires are modeled with coupled meteorology-chemistry models.  Historically, the aerosol emissions from the fire would be modeled by a separate chemistry model that only used the meteorology model as an input (e.g. offline coupling).  However, now you can fully couple (e.g. online coupling) the chemistry with the weather such that the heat and aerosol released from the fire perturbs the meteorological/radiation calculations in the next iterated time step.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2015-05-03T02:07:13.517" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4798" PostTypeId="1" AcceptedAnswerId="4802" CreationDate="2015-05-03T14:16:47.427" Score="23" ViewCount="10238" Body="&lt;p&gt;What percent of the Earth's core is uranium?  And how much of the heat at the core is from radioactive decay rather than other forces?&lt;/p&gt;&#xA;" OwnerUserId="2866" LastActivityDate="2023-02-11T01:54:57.740" Title="What percent of the Earth's core is uranium?" Tags="|core|uranium|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4800" PostTypeId="2" ParentId="4535" CreationDate="2015-05-03T14:31:48.340" Score="0" Body="&lt;p&gt;Yes, Here is a very interesting discussion on the Thought Experiment of what would happen to the Earth is the Sun disappeared.&lt;br&gt;&#xA;&lt;a href=&quot;http://youtu.be/rltpH6ck2Kc&quot; rel=&quot;nofollow&quot;&gt;http://youtu.be/rltpH6ck2Kc&lt;/a&gt;&#xA;Miles of ice actually act as an insulator.  Chemosynthesis will continue.&lt;/p&gt;&#xA;" OwnerUserId="2866" LastActivityDate="2015-05-03T14:31:48.340" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4801" PostTypeId="2" ParentId="4787" CreationDate="2015-05-03T19:11:20.070" Score="10" Body="&lt;p&gt;You are seeing an older jet contrail and its shadow. You can also see some newer contrails, and maybe even some older ones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Contrails are not necessarily continuous. For example, the contrail that appears to be horizontal in the image below appears to magically appear near the left end of the image.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://web.archive.org/web/20150913071323if_/http://science-edu.larc.nasa.gov/SCOOL/images/contrail5.jpg&quot; alt=&quot;Image of a contrail that appears to suddenly start in the middle of the sky&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's what you are seeing in your image, but in this case the contrail in question appears to be vertical. The contrail stops about 1/3 the way up the picture. Given that the contrail gets thicker with increasing height up the picture, and becomes very diffuse near the top, I suspect that where the contrail stops is the youngest part of the contrail. That would mean the plane was flying away from your position (i.e., toward the horizon visible in the picture). The contrail stops at that point because the plane entered a region of dry, stable air. Contrails persist for seconds to several hours, depending on the local atmospheric conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What about the dark band below the contrail? That's the contrail's volumetric shadow. You were in just the right place to see it. Notice that while the contrail is twisted and not quite straight, that dark band is straight. If you look closely, you can see that it doesn't end at the horizon. It appears to extend into the water. It's a shadow, a volumetric shadow to be precise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The next two links are to images that show exactly this effect. These images appear to be copyrighted, so I'm going to leave them as links rather than embed them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://web.archive.org/web/20150920011007if_/http://www.srh.noaa.gov/images/key/Gallery/Jim/Sun/Optic/images/IMG_1680.JPG&quot; rel=&quot;nofollow noreferrer&quot;&gt;Link to image portraying a jet chasing it's volumetric shadow&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.atoptics.co.uk/atoptics/contr1.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Link to another image of a contrail and its volumetric shadow&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, this is a very striking example of the volumetric shadow from a contrail, in this case the launch of STS-98. This image is from Wikipedia, so it's fair use. In other images (you can search for them) taken from other angles, the shadow isn't nearly as striking, sometimes even non-existent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Atlantis_launch_plume_edit.jpg/716px-Atlantis_launch_plume_edit.jpg&quot; alt=&quot;Striking image of STS-98 launch, with volumetric shadow of the exhaust appearing to intersect the Moon&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2018-06-08T21:48:25.517" LastActivityDate="2018-06-08T21:48:25.517" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="4802" PostTypeId="2" ParentId="4798" CreationDate="2015-05-03T21:08:02.357" Score="31" Body="&lt;p&gt;Good question! Geochemists and geophysicists agree to disagree, sometimes quite strongly. There are also disagreements within each group as well as between the two groups.&lt;/p&gt;&#xA;&lt;p&gt;It's not just uranium. There are four isotopes whose half-lives are long enough that they can be primordial and whose half-lives are not so long that they don't produce much heat. These four isotopes are&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Uranium 235, with a half-life of 0.703 billion years,&lt;/li&gt;&#xA;&lt;li&gt;Potassium 40, with a half-life of 1.277 billion years,&lt;/li&gt;&#xA;&lt;li&gt;Uranium 238, with a half-life of 4.468 billion years, and&lt;/li&gt;&#xA;&lt;li&gt;Thorium 232, with a half-life of 14.056 billion years.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The consensus view amongst geochemists is that there is very little, if any, of any of these isotopes in the Earth's core. Potassium, thorium, and uranium are chemically active. They readily oxidize. In fact, they readily combine chemically with lots other elements -- but not iron. They are strongly lithophilic elements. Moreover, all three are &amp;quot;incompatible&amp;quot; elements. In a partial melt, they have a strong affinity to stay in the molten state. This means that relative to solar system abundances, all three of these elements should be strongly enhanced in the Earth's crust, slightly depleted in the Earth's mantle, and strongly depleted in the Earth's core.&lt;/p&gt;&#xA;&lt;p&gt;Geophysicists look at the amount of heat needed to drive the Earth's magnetic field, and at the recent results from neutrino observations. From their perspective, the amount of residual heat from the Earth's formation is not near enough to drive the geomagneto. The growth of the Earth's inner core creates some heat, but not near enough to sustain the geodynamo. Geophysicists want a good amount of heat flux across the core mantle boundary to sustain the geodynamo, and to them the only viable source is radioactivity. Recent geoneutrino experiments appear to rule out uranium or thorium in the Earth's core, but not potassium 40. The neutrinos generated from the decay of potassium 40 are not detectable using current technology.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2020-09-23T08:53:02.147" LastActivityDate="2020-09-23T08:53:02.147" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="4803" PostTypeId="1" AcceptedAnswerId="4805" CreationDate="2015-05-04T01:17:45.730" Score="1" ViewCount="160" Body="&lt;p&gt;What would happen to a tornado if a Large, Immovable, Unbreakable and Obsidian Cube was in its path?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The tornado is on a flat plain... but is heading towards the cube.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By large, I mean the length of the cube's edges is as long as half the width/height of the tornado, whichever is larger.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or is this more Physics, instead, of Earth Science?&lt;/p&gt;&#xA;" OwnerUserId="2868" LastEditorUserId="64" LastEditDate="2015-05-04T13:12:56.430" LastActivityDate="2015-05-04T13:12:56.430" Title="Tornadoes meeting with an Immovable, Unbreakable, Large Cube" Tags="|meteorology|tornado|dynamics|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4804" PostTypeId="1" AcceptedAnswerId="5203" CreationDate="2015-05-04T12:40:04.263" Score="14" ViewCount="2824" Body="&lt;p&gt;In images of the Earth taken from spacecraft (or composite images thereof), the color rendering seems to be really inconsistent.&lt;/p&gt;&#xA;&lt;h2&gt;Examples&lt;/h2&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/T2cr1.jpg&quot; alt=&quot;Visible Earth Image #1&quot; /&gt;&#xA;&lt;em&gt;(Source: NASA, &lt;a href=&quot;https://visibleearth.nasa.gov/images/57735/the-blue-marble-land-surface-ocean-color-sea-ice-and-clouds&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://visibleearth.nasa.gov/images/57735/the-blue-marble-land-surface-ocean-color-sea-ice-and-clouds&lt;/a&gt;)&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is one of NASA's composite images. Here, the Sahara is yellow.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/fy8lb.jpg&quot; alt=&quot;Visible Earth Image #2&quot; /&gt;&#xA;&lt;em&gt;(Source: NASA, &lt;a href=&quot;https://visibleearth.nasa.gov/images/55418/the-blue-marble-from-apollo-17&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://visibleearth.nasa.gov/images/55418/the-blue-marble-from-apollo-17&lt;/a&gt;)&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is a photo from an Apollo mission. Here, the Sahara is an orange/red ochre. This is a very different color.&lt;/p&gt;&#xA;&lt;p&gt;I realize that there are annual variations to be expected in the color of the landscape, but the above differences seem to be too large to be accounted for by that effect.&lt;/p&gt;&#xA;&lt;p&gt;Is the Sahara ochre or yellow?&lt;/p&gt;&#xA;" OwnerUserId="669" LastEditorUserId="4849" LastEditDate="2020-08-06T20:31:52.657" LastActivityDate="2020-08-06T20:31:52.657" Title="What color is the Sahara desert, as seen from orbit?" Tags="|remote-sensing|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="4805" PostTypeId="2" ParentId="4803" CreationDate="2015-05-04T13:06:58.093" Score="4" Body="&lt;p&gt;It depends.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take a look at &lt;a href=&quot;https://ams.confex.com/ams/27SLS/videogateway.cgi/id/28354?recordingid=28354&quot; rel=&quot;nofollow&quot;&gt;this recorded presentation&lt;/a&gt; from the &lt;a href=&quot;https://ams.confex.com/ams/27SLS/webprogram/meeting.html#Sunday1&quot; rel=&quot;nofollow&quot;&gt;27th Conference on Severe Local Storms&lt;/a&gt; by David C. Lewellen and the accompanying &lt;a href=&quot;https://ams.confex.com/ams/27SLS/webprogram/Manuscript/Paper254357/SLS14_pap_submit.pdf&quot; rel=&quot;nofollow&quot;&gt;pre-print&lt;/a&gt;.  This talk focuses on the effect of buildings on tornadoes though the buildings are examined as fixed blocks they are not modified or damaged, but remain a fixed obstacle to the tornado (he toward the end does show that he models forces of the tornado on the building but does not allow that to change the building).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The effect of the block depends on whether the tornado is high or low swirl, the relative position of the block to the tornado and the size of the tornado.  The block weakened some tornadoes and strengthened others.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2015-05-04T13:12:00.970" LastActivityDate="2015-05-04T13:12:00.970" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4806" PostTypeId="2" ParentId="4788" CreationDate="2015-05-04T16:22:47.463" Score="6" Body="&lt;p&gt;In the mid-latitudes we experience 4 seasons (winter, spring, summer and autumn) due to the large annual variation in sunlight due to the tilt of the earth in its orbit.   The &lt;a href=&quot;http://en.wikipedia.org/wiki/Tropics&quot; rel=&quot;noreferrer&quot;&gt;tropical latitudes&lt;/a&gt;, however, do not see large annual variations in sunlight or temperature and instead define their seasons by precipitation changes e.g. wet and dry seasons. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some examples of a wet/dry climate are &lt;a href=&quot;http://en.wikipedia.org/wiki/Tropical_monsoon_climate&quot; rel=&quot;noreferrer&quot;&gt;monsoon climates&lt;/a&gt; and &lt;a href=&quot;http://en.wikipedia.org/wiki/Tropical_savanna_climate&quot; rel=&quot;noreferrer&quot;&gt;savanna climates&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://en.wikipedia.org/wiki/Monsoon&quot; rel=&quot;noreferrer&quot;&gt;monsoon&lt;/a&gt; is driven by seasonal changes in wind directions.  The typical setup is offshore flow during the dry season and onshore flow in the wet season with a mechanism similar to the sea breeze (e.g. driven by temperature differences between land and sea).  During the dry season, dry  air flows out to sea and during the wet season, moist air flows inland from the sea, rises and produces rain.  The monsoon circulation occurs in parts of Africa, Asia, Northern Australia and arguably in the North America desert southwest (debatable because it lacks a true seasonal flow reversal).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The savanna climate generally have a dry season of varying intensity and length and a rainy season in the remainder of the year.  Total rainfall in savannas tends to be less than that in monsoon regions.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both of these wet/dry climates involve interaction with the &lt;a href=&quot;http://en.wikipedia.org/wiki/Intertropical_Convergence_Zone&quot; rel=&quot;noreferrer&quot;&gt;inter tropical convergence zone (ITCZ)&lt;/a&gt;, which is a persistent band of rising air and thunderstorms near the equator.  It moves north and south with changes in location of the sun seasonally and responds to the monsoon circulations and ends up merging with them.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other tropical climates are wet all year long (&lt;a href=&quot;http://en.wikipedia.org/wiki/Tropical_rainforest_climate&quot; rel=&quot;noreferrer&quot;&gt;rainforest climates&lt;/a&gt;) and dry all year long (&lt;a href=&quot;http://en.wikipedia.org/wiki/Desert_climate#Hot_desert_climates&quot; rel=&quot;noreferrer&quot;&gt;desert climates&lt;/a&gt;).  The rain forests are equatorial and dominated by the ITCZ year round.  The hot deserts are around 15-30 N/S latitude and are favored on the western extents of the continents.  The latitude preference derives from the descending branch of the &lt;a href=&quot;http://en.wikipedia.org/wiki/Hadley_cell&quot; rel=&quot;noreferrer&quot;&gt;Hadley cell&lt;/a&gt;, which suppresses precipitation and causes warming.  The western continental preference comes from the direction of the &lt;a href=&quot;http://en.wikipedia.org/wiki/Trade_wind&quot; rel=&quot;noreferrer&quot;&gt;trade winds&lt;/a&gt;, which are easterlies in the tropics. &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-05-04T16:22:47.463" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4807" PostTypeId="2" ParentId="4804" CreationDate="2015-05-04T16:36:44.557" Score="12" Body="&lt;p&gt;Remember from school when you learned that light is actually photons oscillating at specific frequencies, and we happen to perceive some of these frequencies as specific colors? Technically, satellites measure reflected light in spectral bands, where each band is actually a range of wavelengths or light frequencies. The raw data that is sent back to earth from the satellite just consists of measurements of the amount of light observed within each band at each pixel. Some bands on most satellites happen to correspond to frequencies that we typically perceive as specific colors (red, green, and blue are the most common), and these colors are typically chosen to visualize data within these bands. (See: &lt;a href=&quot;http://earthobservatory.nasa.gov/blogs/elegantfigures/2013/10/22/how-to-make-a-true-color-landsat-8-image/&quot;&gt;http://earthobservatory.nasa.gov/blogs/elegantfigures/2013/10/22/how-to-make-a-true-color-landsat-8-image/&lt;/a&gt; for a better explanation of how composite imagery is made) So, there are many reasons why the color would change between composite images, including:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The persons creating the different composite images chose&#xA;slightly different hues for red, green, and blue to represent those&#xA;values corresponding to that approximate color on the ground.&lt;/li&gt;&#xA;&lt;li&gt;The two instruments (MODIS or Landsat vs. Apollo) collected data for those general bands at different times of day and/or over different ranges of actual light wavelengths and/or used different algorithms to calculate the amount of light reflected in each band so the measured values for the amount of reflected red, green, and blue light in the different images differs&lt;/li&gt;&#xA;&lt;li&gt;Something altered the spectral properties of the sand or atmosphere (ex. it rained or there was a duststorm) around the time one of the images was taken so the actual reflectance values in the different images differs&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The short answer to your question is probably that it varies over time and space and by the instrument capturing the image, and, on average, is somewhere between yellow and ochre. &lt;/p&gt;&#xA;" OwnerUserId="2871" LastEditorUserId="2871" LastEditDate="2015-05-06T04:09:11.880" LastActivityDate="2015-05-06T04:09:11.880" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4808" PostTypeId="2" ParentId="2882" CreationDate="2015-05-04T16:49:15.273" Score="5" Body="&lt;h3&gt;The polar vortex&lt;/h3&gt;&#xA;&lt;p&gt;The AMS glossary defines the polar vortex as:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A planetary-scale mid- to high-latitude circumpolar cyclonic circulation, extending from the middle troposphere to the stratosphere. The Northern Hemisphere vortex often features two centers—one near Baffin Island and the other over northeast Siberia—with analogous circumpolar asymmetry atypical in the Southern Hemisphere. The westerly airflow is largely a manifestation of the thermal wind above the polar frontal zone of middle and subpolar latitudes. The vortex is strongest during the winter in the upper troposphere and stratosphere when the pole-to-equator temperature gradient is strongest. The stratosphere component of the circulation may be referred to separately as the “polar stratospheric vortex.” In summer, the strongest westerly circulation is largely confined to the troposphere, and the polar stratospheric vortex reverses in the upper stratosphere because of solar heating during the polar day.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This first descriptions of the polar vortex date back to the 1940s.  You'll also note that the description above describes an upper tropospheric and stratospheric circulation e.g. this is is something happening well above the surface of the earth.&lt;/p&gt;&#xA;&lt;p&gt;The recent popular use of polar vortex to describe any particularly cold air mass can probably be traced back to someone (either a meteorologist of psuedo-meteorologist) on twitter making reference to it and then &amp;quot;going viral&amp;quot;.  However the media got a hold of the word, they are quite consistent in misusing it.&lt;/p&gt;&#xA;&lt;p&gt;The definition above mentions&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The westerly airflow is largely a manifestation of the thermal wind above the polar frontal zone of middle and subpolar latitudes&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;What this means is that the position and strength of polar vortex (the circulation up around the stratosphere) is strongly influenced by the position of strong surface cold fronts coming out of the poles.  The strong cold snaps are not the polar vortex, and the southern push of the high altitude polar vortex is a response of the cold snap, not the other way around.&lt;/p&gt;&#xA;&lt;h3&gt;Cut off lows&lt;/h3&gt;&#xA;&lt;p&gt;Cut off lows are not new either.  A mid-latitude trough can be cut off from the westerly flow and you end up with a cutoff or closed low.  These tend to be persistent, stationary mid and upper level lows that can last for days.  You can see an example of a cut off low in the flow over the US in &lt;a href=&quot;https://www.youtube.com/watch?v=Msccmq4CeOg&quot; rel=&quot;nofollow noreferrer&quot;&gt;this video&lt;/a&gt;.  Focus over the southern tip of Lake Michigan and you'll see it.  These type of cutoff lows can occur anywhere in the mid-latitudes.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-05-05T12:44:27.370" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4809" PostTypeId="2" ParentId="2733" CreationDate="2015-05-04T17:23:44.683" Score="1" Body="&lt;p&gt;If these were polar stratospheric clouds, that could explain a brighter than normal sky either before sunrise or after sunset.  The higher the clouds are, the more lead/lag time you will have to observe the phenomena before the sun comes into view.  The reason for this is simply that the clouds are in direct line-of-sight with both you and the sun, but you and the sun are not in line-of-sight.  The sun illuminates these clouds and being cold icy clouds they reflect much of this light to your eyes.  100% of the light you see is scattered giving the light a diffuse glow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, I'm not aware of any stratospheric forecast products for these clouds.  The closest thing is an analysis of the 450 K $\theta$-surface showing area within the polar vortex with temperature at or below -78 C.  These depict the area within the polar vortex that are favorable for polar stratospheric clouds.  However, these do not show where the favorable area is, nor give an indication if these clouds will actually form.  You can view the northern hemisphere plots &lt;a href=&quot;http://www.cpc.ncep.noaa.gov/products/stratosphere/polar/polar.shtml#plot8&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;.  The other stratospheric products deal with the size of the polar vortex, UV-B penetration and ozone analysis which do not aid in the forecast of these clouds.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-05-04T17:23:44.683" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4811" PostTypeId="2" ParentId="139" CreationDate="2015-05-04T23:23:35.870" Score="6" Body="&lt;p&gt;A way to understand Rocky Mountains is (as mentioned) to look at the destiny of the Farrallon Plate. In the &lt;a href=&quot;http://en.wikipedia.org/wiki/Laramide_orogeny&quot;&gt;collision with North America&lt;/a&gt;, it didn't &lt;a href=&quot;http://en.wikipedia.org/wiki/Subduction&quot;&gt;subduct&lt;/a&gt; but rather slide under the lithosphere until it finally get a steeper angle and subducts at the eastern rim of the Rockies. This long journey could also lead to processes causing destabilization and &lt;a href=&quot;http://www.nature.com/nature/journal/v472/n7344/full/nature10001.html&quot;&gt;delamination&lt;/a&gt; of the lithosphere under the Colorado Plateau, and causing its rapid uplift during Cenozoic. Recent data from the &lt;a href=&quot;http://www.usarray.org/&quot;&gt;USArray&lt;/a&gt; have improved the models (and generates new questions). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The orogeny is somehow still ongoing as the Farrallon Plate still affect and weakens the North America Plate so that the Rio Grande rifting can take place. The Front Range Uplift is also the reason for the Denver Basin that fills with sediments from the orogeny. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2015-05-04T23:34:34.260" LastActivityDate="2015-05-04T23:34:34.260" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4813" PostTypeId="2" ParentId="4789" CreationDate="2015-05-05T07:41:16.090" Score="4" Body="&lt;p&gt;There is a YouTube clip &lt;a href=&quot;https://www.youtube.com/watch?v=2ythE-hJiNE&quot;&gt;How the Earth Would Look Like Without Oceans&lt;/a&gt;, it is only 1 minute 34 seconds; however, it is very graphical with no commentary, but with information about features of the ocean basins, ridges (and even the location of the Titanic!).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Information presented also includes spreading rates and depths.&lt;/p&gt;&#xA;" OwnerDisplayName="user2872" LastEditorDisplayName="user2872" LastEditDate="2015-05-05T07:46:35.160" LastActivityDate="2015-05-05T07:46:35.160" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4814" PostTypeId="1" AcceptedAnswerId="4815" CreationDate="2015-05-05T15:49:18.863" Score="13" ViewCount="1007" Body="&lt;p&gt;I know that forests can change the local temperature, but what about rainfall?.  Do forests affect rainfall in their region? I have read that if a forest is very big, it can cause minor changes to local rainfall and temperature.  How does that work?&lt;/p&gt;&#xA;" OwnerUserId="2875" LastEditorUserId="543" LastEditDate="2015-05-06T01:53:07.110" LastActivityDate="2016-01-08T21:40:28.883" Title="Do forests affect local rainfall and climate significantly?" Tags="|climate|land-surface|forest|rainfall|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4815" PostTypeId="2" ParentId="4814" CreationDate="2015-05-06T02:07:00.710" Score="11" Body="&lt;p&gt;For rain to fall, water vapour must exist in sufficient quantities in the atmosphere. The main source of atmospheric water vapour is evaporation from oceans. However, evaporation from large bodies of water such as lakes and dams also contributes. Another &lt;a href=&quot;http://rainforests.mongabay.com/0906.htm&quot; rel=&quot;nofollow&quot;&gt;significant contributor&lt;/a&gt;, on a local level, is &lt;a href=&quot;http://water.usgs.gov/edu/watercycletranspiration.html&quot; rel=&quot;nofollow&quot;&gt;transpiration&lt;/a&gt; from &lt;a href=&quot;http://blog.cifor.org/10316/make-it-rain-planting-forests-to-help-drought-stricken-regions&quot; rel=&quot;nofollow&quot;&gt;forests&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the Amazon alone creates 50-80 percent of its own rainfall through transpiration&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Removing forests has &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the biggest impact on cross-continental transport of water vapour&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Removal of trees from an area of forest immediately stops transpiration in the that area. This causes less rain to fall in that area. It changes the way light is reflected from the Earth's surface, which changes the heating characteristics of the ground, which changes air movements. It will also have an influence on ground water levels and depending on local geology can bring salt to the surface causing salt scars and eventually desertification.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="4789" LastEditDate="2016-01-08T21:40:28.883" LastActivityDate="2016-01-08T21:40:28.883" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4816" PostTypeId="1" CreationDate="2015-05-06T07:20:20.697" Score="3" ViewCount="1261" Body="&lt;p&gt;Below is a picture of a typical sunset that I have been observing lately at an undisclosed location in the Southern Hemisphere:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/T2HDE.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given that the base of the picture is parallel to sea level, you can see that the line where the dark blue meets the red in the sky, is on an angle of elevation of approximately 7 - 8 degrees.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there an explanation for this phenomenon (which I have observed for the past few days) and is it related to my position on the Earth, or the time of year?&lt;/p&gt;&#xA;" OwnerUserId="51" LastActivityDate="2016-04-05T22:55:12.213" Title="Why is the colour gradient in the sky at sunset on an angle?" Tags="|meteorology|atmosphere|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4819" PostTypeId="5" CreationDate="2015-05-06T12:22:11.173" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2015-05-06T12:22:11.173" LastActivityDate="2015-05-06T12:22:11.173" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4820" PostTypeId="4" CreationDate="2015-05-06T12:22:11.173" Score="0" Body="Acid rain is a rain or any other form of precipitation that is unusually acidic, meaning that it possesses elevated levels of hydrogen ions (low pH). It can have harmful effects on plants, aquatic animals and infrastructure." OwnerUserId="2880" LastEditorUserId="2880" LastEditDate="2015-05-06T12:58:00.323" LastActivityDate="2015-05-06T12:58:00.323" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4822" PostTypeId="1" AcceptedAnswerId="4824" CreationDate="2015-05-06T14:20:33.113" Score="16" ViewCount="44809" Body="&lt;p&gt;&lt;a href=&quot;https://worldbuilding.stackexchange.com/questions/15653/is-a-planets-southern-hemisphere-necessarily-warmer-than-the-north&quot;&gt;This Question&lt;/a&gt; on Worldbuilding is based on the presumption that there is a greater amount of landmass on the Earth's Northern Hemisphere than there is on the Southern Hemisphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;While researching to form an answer to this question, I found it difficult to find a map that accurately portrays which hemisphere actually has a greater landmass, and started thinking about the actual nature of the question - assuming there &lt;strong&gt;is&lt;/strong&gt; a greater concentration of landmass in the Northern Hemisphere than the South, why is that? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does it have anything to do with the rotational procession of the Earth? Is it more related to the Earth's natural fault lines?  Or is there something else that influences a greater accumulation of land mass on our Northern Hemisphere (if that is, in fact, an accurate assumption)?&lt;/p&gt;&#xA;" OwnerUserId="2882" LastEditorUserId="-1" LastEditDate="2017-04-13T12:52:35.360" LastActivityDate="2021-09-07T15:15:14.010" Title="(Why) Is there more landmass on Earth's Northern hemisphere than the Southern Hemisphere?" Tags="|plate-tectonics|geography|land-surface|" AnswerCount="6" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4823" PostTypeId="2" ParentId="3140" CreationDate="2015-05-06T15:02:37.910" Score="4" Body="&lt;p&gt;It is definitely possible to completely drain an aquifer.  However, as the potentiometric surface (water level) in the aquifer drops, extraction of water becomes less economical, but the perceived value of the water increases. It is possible to apply &quot;unconventional&quot; drilling techniques like directional drilling and fracking to extract groundwater. You could potentially get philosophical and argue that there is a point where the aquifer no longer meets the &lt;a href=&quot;https://en.wikipedia.org/wiki/Aquifer&quot; rel=&quot;nofollow&quot;&gt;definition of an aquifer&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your question is really a matter of scale.  The USGS Principal aquifer map depicts the Ogallala aquifer as a complete and continuous hydrostratigraphic unit because that map is a national-scale map.  It would be more appropriate to call it the Ogallala aquifer system, to remove implications that it is one continuous, well-connected aquifer system that runs across several states.  It is much more likely that this aquifer is a group of hydrostratigraphic units separated by faults, confining units, and lateral discontinuities.  Because of this horizontal heterogeneity and because pumping influence such as cones of depression is generally localized, you could potentially completely deplete some portion of the aquifer system while leaving other portions with some water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of the water budget, as you have shown in the above USGS figure, discharge is already outpacing recharge. In their &lt;a href=&quot;http://www.kgs.ku.edu/Publications/pic18/pic18_1.html&quot; rel=&quot;nofollow&quot;&gt;Public Information Circular 18&lt;/a&gt;, the Kansas Geological Survey projects that some parts of the aquifer system will be depleted within as soon as 25 years, while other regions have a life expectancy of between 50 and 200 years. In an &lt;a href=&quot;http://lubbockonline.com/local-news/2014-08-09/drying-times-could-rapidly-depleting-ogallala-aquifer-run-dry#.VUoiA_lVhBc&quot; rel=&quot;nofollow&quot;&gt;interview with the Lubbock Avalanche-Journal&lt;/a&gt;, the Center for Geospatial Technology at Texas Tech said that some regions of the aquifer in Texas only have 15 years of water left.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As water is removed from an aquifer, the pressure that water exerts to help hold up the aquifer skeleton is reduced.  The reduction in water pressure can cause deformation in the aquifer. Some component of this deformation is recoverable (elastic). However, if the stresses on the aquifer exceed that of what the dewatered material can handle, then the dewatered aquifer/confining layers could undergo permanent compaction, leading to a decreased ability of the aquifer to store water. See &lt;a href=&quot;http://pubs.usgs.gov/circ/circ1182/&quot; rel=&quot;nofollow&quot;&gt;USGS Circular 1182&lt;/a&gt; for more information on these concepts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While the technology exists to implement artificial recharge, either via injection well or infiltration ponds/galleries, this technique requires adequate geochemical conditions and an appropriate recharge source. Once an aquifer system is stressed to the point of compaction, its storage is permanently decreases, reducing its value as a candidate for artificial recharge.  For more information on artificial recharge, see the &lt;a href=&quot;https://water.usgs.gov/ogw/artificial_recharge.html&quot; rel=&quot;nofollow&quot;&gt;USGS website&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="510" LastActivityDate="2015-05-06T15:02:37.910" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4824" PostTypeId="2" ParentId="4822" CreationDate="2015-05-06T16:07:49.633" Score="11" Body="&lt;p&gt;It would be a strange coincidence (but of course possible) if the landmass would be exactly evenly divided between the northern and southern hemispheres, as defined by the equator. However, you can cut the globe with &lt;em&gt;another&lt;/em&gt; plane and form two hemispheres that have the same landmass, eg. any vertical plane that goes through the &lt;a href=&quot;https://en.wikipedia.org/wiki/Geographical_centre_of_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geographical centre of Earth&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/o2U8W.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/o2U8W.png&quot; alt=&quot;Map of @whuber&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;&lt;a href=&quot;https://gis.stackexchange.com/questions/83022/what-is-centroid-of-all-lands-of-earth&quot;&gt;Calculation of Geographical centre&lt;/a&gt; of Earth by &lt;a href=&quot;https://gis.stackexchange.com/users/664/whuber&quot;&gt;whuber&lt;/a&gt; at &lt;a href=&quot;https://gis.stackexchange.com/&quot;&gt;GIS stackexchange&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The landmass distribution is largely depending of the location of the continental plates, but &lt;a href=&quot;https://www2.nau.edu/rcb7/globaltext2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Paleogeography maps&lt;/a&gt; also suggest that the breakup of Pangaea follows other laws than an even distribution between north and south hemisphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problems to &lt;em&gt;find a map that accurately portrays which hemisphere actually has a greater landmass&lt;/em&gt;, is probably related to the fact that many popular (and in many ways useful!) map projections are not made to show area relations. Use a globe or &lt;a href=&quot;https://en.wikipedia.org/wiki/Map_projection#Equal-area&quot; rel=&quot;nofollow noreferrer&quot;&gt;equal area&lt;/a&gt; projection to compare the size of landmasses. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This might also be an interesting article for you and a starting point for further research: &lt;a href=&quot;http://151.100.51.154/dst1/sciterra/sezioni/doglioni/Publ_download/2009RiguzzietalTectonophysics.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Riguzzi et al. (2009) Can Earth's rotation and tidal despinning drive plate tectonics?&lt;/a&gt;. The authors argue that there is a correlation between tectonic movements and rotation of the Earth and the Moon's revolution plane. Tomographic data of slab dip angles support the point and this might also be part of an explanation why earthquakes and volcanism varies along the latitudes and might be rare in the polar regions. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="-1" LastEditDate="2017-04-13T12:33:47.360" LastActivityDate="2017-01-12T15:30:15.927" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4825" PostTypeId="1" AcceptedAnswerId="4845" CreationDate="2015-05-06T17:24:13.813" Score="9" ViewCount="2292" Body="&lt;p&gt;I was recently watching the San Andreas trailer and a thought occurred to me as to how best to prevent earthquakes. I figured, why not nuke it? My professor said that it's possible for nukes to stop hurricanes so it got me thinking as to what else nukes could stop (besides humanity). The friction that develops is because of two plates moving against each other, right? So if you used enough nuclear bombs to completely obliterate a plate, the other plate wouldn't have anything to rub against, correct?&lt;/p&gt;&#xA;" OwnerUserId="2883" LastEditorUserId="2536" LastEditDate="2017-05-28T10:04:16.463" LastActivityDate="2018-12-06T09:36:26.163" Title="Will a nuclear bomb stop an earthquake from happening?" Tags="|earthquakes|plate-tectonics|transform-fault|geoengineering|" AnswerCount="2" CommentCount="14" ContentLicense="CC BY-SA 3.0" />
  <row Id="4828" PostTypeId="1" AcceptedAnswerId="4830" CreationDate="2015-05-06T19:41:58.860" Score="7" ViewCount="808" Body="&lt;p&gt;I am running some test forecasts using WRF 3.6.1. and am having some problems with my grids. Specifically, I am specifying a parent and nest domain each with 25 points for longitude and latitude (so that there is a point right at the middle of the inner domain and the parent grid points are coincident with inner grid points with a 3:1 nesting ratio).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would expect an output of 25 by 25 points for each domain. however, I am only getting 24 by 24 points as output. In fact if I look at the geom_em or met_em netcdf files generated by WPS I already get only grids with 24 by 24 points. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What's going on?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is the geogrid section of my namelist.wps file:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;&amp;amp;geogrid&#xA; parent_id         =   1,   1,&#xA; parent_grid_ratio =   1,   3,&#xA; i_parent_start    =   1,  9,&#xA; j_parent_start    =   1,  9,&#xA; s_we              =   1,  1,&#xA; e_we              =  25, 25,&#xA; s_sn              =   1,  1,&#xA; e_sn              =  25,  25,&#xA; geog_data_res     = '10m','2m',&#xA; dx = 18000,&#xA; dy = 18000,&#xA; map_proj = 'lambert',&#xA; ref_lat   =  53.526,&#xA; ref_lon   =  -113.529,&#xA; truelat1  =  53.526,&#xA; truelat2  =  53.526,&#xA; stand_lon =  -113.529,&#xA; geog_data_path = '/media/data/WRF3.6.1/data/geog/'&#xA;/&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="2885" LastEditorUserId="64" LastEditDate="2015-05-06T20:55:41.647" LastActivityDate="2015-05-06T20:55:41.647" Title="WRF output grid is smaller than input definition" Tags="|models|wrf|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4829" PostTypeId="2" ParentId="4825" CreationDate="2015-05-06T20:00:01.450" Score="10" Body="&lt;p&gt;A nuclear explosion in the subsurface will result in ground motion which in theory can trigger an earthquake (due to passage of dynamic waves) if a locked fault has already accumulated sufficient strain over the last few decades/centuries due to slow motion of plates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Having said that all the nuclear stockpile in the world is not enough to obliterate even a small part of the plate boundary. The 1960 Chilean earthquake released accumulated strain energy of the order of 3 Gigatons of TNT or 200 Gigatons of TNT equiv or 12 million Hiroshima type bombs (Numbers are based on calculations by JC Lahr and are available at &lt;a href=&quot;http://www.jclahr.com/alaska/aeic/magnitude/energy_calc.html&quot;&gt;http://www.jclahr.com/alaska/aeic/magnitude/energy_calc.html&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So yes, an explosion in the subsurface can probably act as a trigger for an impending earthquake but it cannot stop if from reoccurring again after few decades/centuries.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2015-05-07T22:09:00.490" LastActivityDate="2015-05-07T22:09:00.490" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4830" PostTypeId="2" ParentId="4828" CreationDate="2015-05-06T20:53:35.100" Score="6" Body="&lt;p&gt;Your model grid is an Arakawa C grid:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/hqXKc.gif&quot; alt=&quot;enter image description here&quot;&gt;&#xA;&lt;sub&gt;Image from Skamarock et al. &lt;a href=&quot;http://www.mmm.ucar.edu/wrf/users/docs/arw_v3.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;A description of the Advanced Research WRF Version 3&lt;/em&gt;&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It appears the geogrid grid generation uses the 25x25 as the furthest extents of the grid (and this is backed up by the grid maximum needing to be a multiple of the grid ratio +1).  As a result, only the &lt;code&gt;u&lt;/code&gt; and &lt;code&gt;v&lt;/code&gt; variables will see 25 grid points and each only in one direction, east/west and north/south respectively.  All other variables are located horizontally on the $\theta$, or scalar points in the middle of the grid boxes and there will only be 24 of these points in your setup leaving most of your grids having a horizontal dimensions of 24x24.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-05-06T20:53:35.100" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4831" PostTypeId="2" ParentId="4597" CreationDate="2015-05-07T07:48:59.980" Score="7" Body="&lt;p&gt;An aptly named webpage from GeoScience Australia: &lt;a href=&quot;http://www.ga.gov.au/ausgeonews/ausgeonews200512/uranium.jsp&quot; rel=&quot;noreferrer&quot;&gt;Why Australia has so much uranium&lt;/a&gt; provides some insight as to some of the reasons behind the Australian continental relative enrichment in uranium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider the following map from the GeoScience webpage:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/2UpDM.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One link that is stated on the website is that in regards to major uranium deposits&quot; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;observations support the conclusion that the large number of uranium deposits and prospects across Australia reflects the &lt;strong&gt;extensive emplacement of uranium-enriched felsic rocks in three main periods of igneous activity&lt;/strong&gt;. While some uranium deposits appear to have formed during these widespread thermal events, &lt;strong&gt;most formed from uranium-enriched source rocks by subsequent low-temperature processes.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;These 3 main periods occur:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Late Archaean (2.69-2.65 Ga)&lt;/li&gt;&#xA;&lt;li&gt;the Palaeo-Mesoproterozoic. (~1.9-1.5 Ga)&lt;/li&gt;&#xA;&lt;li&gt;and a bit younger in eastern deposits, the Silurian to the Permian (0.43-0.25 Ga)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The last point in bold above is elaborated further by the website, that uranium mineralisation being younger than the related intrusive igneous rocks.  Particularly evidenced by deposits found in calcrete, sandstone and unconformities:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;appear to have formed as a result of uranium mobilisation from older uranium-enriched source rocks under low-temperature oxidising conditions, and precipitation by redox reactions. The high-grade deposits are likely to reflect relatively more efficient oxidation-reduction systems.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user2872" LastActivityDate="2015-05-07T07:48:59.980" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4832" PostTypeId="1" AcceptedAnswerId="4833" CreationDate="2015-05-07T10:06:14.883" Score="6" ViewCount="1283" Body="&lt;p&gt;I have recently bought a medium sized plot of wood/scrub land. Half of this plot was once used to dump shale from coal mines, which means I have a lot of shale.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have been wondering/looking for possible uses for the stuff. One thought I've had is to make &quot;mud bricks&quot; however I can't find any mention of whether it is possible or not. I know the traditional method uses loamy soil but would it work with shale?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't have a kiln or any way of baking the bricks, so would be reliant on the sun. I was thinking maybe adding water and maybe some loam?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Aside: there are no suitable tags for my question and I do not have the reputation to add any, I'm thinking I could be on the wrong site for this question, if I am, please advise me of a more suitable one. &lt;/p&gt;&#xA;" OwnerUserId="2886" LastEditorUserId="2536" LastEditDate="2015-05-07T15:45:39.927" LastActivityDate="2015-05-08T00:34:10.330" Title="Mud bricks with shale" Tags="|resources|forest|environmental-protection|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4833" PostTypeId="2" ParentId="4832" CreationDate="2015-05-07T13:20:51.167" Score="4" Body="&lt;p&gt;Your idea has merit. Shale is classified by geologists as being a mudstone. It is composed of silt and clay sized minerals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to this &lt;a href=&quot;http://geology.com/rocks/shale.shtml&quot; rel=&quot;nofollow&quot;&gt;geology website&lt;/a&gt;, shales can be crushed to produce a clay and then mixed with water. These days, items that were once made from natural clay, such as terracotta pots and tiles for roofs, are now made from crushed shale.  &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Extra Information&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing to be mindful of is that clays expand when wet and contract when dry. Anything you make from it, such as bricks, that isn't baked or protected from water by a sealed coating will expand and contract according to it moisture content.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another application which you may want to consider is to supply crushed shale as a garden mulch or other such landscaping product.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2015-05-07T13:56:32.317" LastActivityDate="2015-05-07T13:56:32.317" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="4834" PostTypeId="1" AcceptedAnswerId="4837" CreationDate="2015-05-07T18:25:19.843" Score="4" ViewCount="476" Body="&lt;p&gt;A &lt;a href=&quot;https://www.google.com/maps/place/Miyazaki,+Miyazaki+Prefecture,+Japan/@31.7825779,131.2343451,187m/data=!3m1!1e3!4m2!3m1!1s0x3538b5f6c768a27b:0xd4ce23b1878ee7d!6m1!1e1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google satellite view&lt;/a&gt; shows an unusual structure on a hillside in Miyazaki Prefecture, Japan (Latitude 31.782600°N, Longitude 131.233881°E):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/jvwYS.png&quot; alt=&quot;Stepped structure on Japanese hillside&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It measures about 170m by 120m and is structured in steps of around 10m, with some parts also showing a grid structure on a scale of around 2m. It appears to be made out of concrete. What could its purpose be?&lt;/p&gt;&#xA;" OwnerUserId="2887" LastEditorUserId="6298" LastEditDate="2022-02-06T17:24:06.200" LastActivityDate="2022-02-06T17:24:06.200" Title="What is the purpose of this large structure on a Japanese hillside?" Tags="|geomorphology|satellites|flooding|seismic-hazards|satellite-oddities|" AnswerCount="1" CommentCount="7" ClosedDate="2015-05-08T21:45:15.677" ContentLicense="CC BY-SA 3.0" />
  <row Id="4835" PostTypeId="2" ParentId="4832" CreationDate="2015-05-08T00:34:10.330" Score="3" Body="&lt;p&gt;Adding to Fred's answer, there are two points you have to take into consideration:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Whether the &quot;shale&quot; is actually composed of clay minerals, or is it something else. You said it's what they took out from a coal mine, so it's probably crushed and milled.&lt;/li&gt;&#xA;&lt;li&gt;Assuming it is clay, there are some problems with that. As Fred said, clays expand and contract with water. Firing it solves the problem - it mineralogically changes the clays to other minerals that do not possess that characteristic. Now, there are clays and there are clays. Some can take in a lot of water (such as smectite) while others don't (illite).&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I would suggest a simple experiment. Take a bowl, fill it with that stuff, soak it completely with water, and let it dry completely in the sun. Do you see any mudcracks in it? If yes, I would recommend against using it for construction without firing it.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-05-08T00:34:10.330" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4836" PostTypeId="1" AcceptedAnswerId="4838" CreationDate="2015-05-08T02:21:22.650" Score="9" ViewCount="94" Body="&lt;p&gt;I was intrigued by &lt;a href=&quot;http://www.slate.com/blogs/future_tense/2014/08/27/napa_earthquake_groundwater_pumping_in_california_won_t_cause_the_big_one.html&quot;&gt;this Slate piece&lt;/a&gt;, more or less a summary of &lt;a href=&quot;http://www.nature.com/nature/journal/v509/n7501/full/nature13275.html&quot;&gt;Amos et al. (2014)&lt;/a&gt;'s Nature article, which essentially states that groundwater depletion and subsequent crustal unloading causes a decrease in the stress normal to the San Andreas fault, thus bringing the fault &quot;closer to failure&quot; (to quote from the abstract).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does that mean, as Eric Holthaus, the author of the Slate post suggests, Amos and his co-authors believe that due to the drought, the next &quot;major&quot; earthquake may not be quite as significant in magnitude? (The idea being that an increase in small-magnitude slip events over several years will help ease the intensity of short-period rupture propagation during a larger event?) Or, does it mean that the released stress is just being redistributed to locked sections of the fault system, which I assume experience decreased Mohr–Coulomb forces due to the region wide groundwater draw down? Elsewhere in the Slate article, for example, Holthaus notes that the &lt;a href=&quot;http://space.io9.com/geology-of-the-napa-valley-earthquake-1626288018?invitelink&quot;&gt;August 2014 Napa Earthquake&lt;/a&gt; actually &lt;a href=&quot;http://www.newscientist.com/article/dn26106-californian-earthquake-piles-stress-on-dangerous-fault.html#.VUwM_GTBzGf&quot;&gt;redistributed some of its released stress&lt;/a&gt; onto the Hayward Fault, which doesn't quite seem to support the &quot;easing&quot; hypothesis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Am I wrong in thinking that the two ideas referenced (easing vs. redistribution) might be mutually exclusive? I sort of wish Holthaus had delved a little deeper in his analysis, since it seems that the clarity of the Slate article takes a fair hit from this inconsistency.&lt;/p&gt;&#xA;" OwnerUserId="2749" LastEditorUserId="2470" LastEditDate="2015-05-08T05:13:50.513" LastActivityDate="2015-05-08T14:05:11.763" Title="Groundwater unloading and corresponding changes in fault zone stick-slip behavior" Tags="|seismology|earthquakes|human-influence|groundwater|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4837" PostTypeId="2" ParentId="4834" CreationDate="2015-05-08T05:40:04.683" Score="11" Body="&lt;p&gt;The structure looks similar to &lt;a href=&quot;http://files.archinect.com/uploads/ai/aiu_fig4-7.jpg&quot; rel=&quot;noreferrer&quot;&gt;this photograph of a &quot;Japanese land retention system&quot;&lt;/a&gt; mentioned in passing towards the bottom of &lt;a href=&quot;http://archinect.com/blog/article/21453621/the-forensic-engineer&quot; rel=&quot;noreferrer&quot;&gt;this webpage&lt;/a&gt;. From the linked page:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Land retention systems in Japan, for example, are often designed as heavy waffle grids which are molded to the topography and cover it to a uniform structural depth.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This seems to correspond roughly to the structure in the question, although the &quot;waffle-grid structure&quot; is only evident in some parts.&#xA;I've been unable to find any more details online about these land retention structures and their design.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As farrenthorpe writes in a comment, the three-dimensional view is probably more informative:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/pOHAQ.png&quot; alt=&quot;3D view&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At first glance the siting seems strange, since there is no major settlement or road below the structure. However, it does overlook a river which, around 3 km downstream, feeds into &lt;a href=&quot;http://www.mbendi.com/facility/tenjin-damu-1346659&quot; rel=&quot;noreferrer&quot;&gt;the Tenjin water storage dam&lt;/a&gt;. In the current Google satellite imagery the riverbed is mostly dry and ongoing engineering work is visible in it, presumably also related to debris/sedimentation control. Similar hillside structures can also be seen on some of the slopes around the dam itself.&lt;/p&gt;&#xA;" OwnerUserId="94" LastActivityDate="2015-05-08T05:40:04.683" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4838" PostTypeId="2" ParentId="4836" CreationDate="2015-05-08T13:57:39.397" Score="1" Body="&lt;p&gt;Changes in water level effect the pore pressure at depth around the fault. The general assumption is that the pore pressure is proportional to fault-normal stress which can be thought of clamping stress (i.e., the stress that prevents it from slipping). Basically the higher the clamping stress the more shear stress is required to make it slip. Now the shear stress on San Andreas accumulates due to plate motion between the North American and Pacific plates and that rate remains unchanged. But the normal stress can change slightly due to water level changes, so it can either advance or retard the occurrence of an earthquake in time. But under no circumstances can it stop them from occurring.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main idea in the paper is that the normal stress on faults have slightly decreased (due to water level drop) which helps to unclamp the fault(s) which in turn increases the background seismicity rates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So given all this, the first argument by (Holthaus) is correct. However the unclamping can also advance (in time) the occurrence of the big one. Having said that please remember that stress changes we are talking about are rather small.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regards to the Napa earthquake: The point of an earthquake is to relive the accumulated shear strain. If there are two faults in parallel (as is the case in the region) and both are accumulating strain then an earthquake on one will decrease the 'effective shear stress' on the other fault, directly parallel to it. However at the same time it will increase the shear at the two ends. So things are slightly more complicated.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2015-05-08T14:05:11.763" LastActivityDate="2015-05-08T14:05:11.763" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4839" PostTypeId="1" AcceptedAnswerId="4847" CreationDate="2015-05-08T16:39:06.207" Score="10" ViewCount="232" Body="&lt;p&gt;If there were lots of geothermal plants—even mobile ones—near a volcano, how much power could this provide? Could the sapping of some of the heat energy make the volcano less likely to erupt?&lt;/p&gt;&#xA;" OwnerUserId="1371" LastEditorUserId="28050" LastEditDate="2015-05-09T01:45:23.073" LastActivityDate="2015-05-10T00:57:57.977" Title="What is the geothermal potential of a volcano?" Tags="|geophysics|volcanology|geochemistry|petrology|geothermal-heat|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4841" PostTypeId="1" AcceptedAnswerId="4842" CreationDate="2015-05-08T18:12:26.877" Score="7" ViewCount="3864" Body="&lt;p&gt;I was reading many articles about estimates of the age of the Earth throughout the ages. I was dumbfounded when I read that Newton, arguably one of the greatest scientists ever to have ‘calculated’ the age of the earth, estimated that the Earth was created in 4000 BCE. Johannes Kepler arrived at a similar result. Which methods did these scientists use to arrive at such conclusions?&lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="94" LastEditDate="2015-05-08T18:36:23.823" LastActivityDate="2019-03-11T13:30:08.100" Title="Newton's estimate of the age of the Earth" Tags="|geology|geochronology|history-of-science|geomythology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4842" PostTypeId="2" ParentId="4841" CreationDate="2015-05-08T18:32:06.640" Score="11" Body="&lt;p&gt;The estimates of Newton and Kepler, and the similar estimates of &lt;a href=&quot;http://en.wikipedia.org/wiki/Dating_creation#Masoretic&quot;&gt;dozens of their contemporaries&lt;/a&gt;, were produced by treating the Bible as &lt;a href=&quot;http://en.wikipedia.org/wiki/Chronology_of_the_Bible&quot;&gt;a historically accurate document&lt;/a&gt; and deriving a chronology from it. I think that a detailed explanation of their techniques would be off-topic for Earth Science, but the Wikipedia page on the &lt;a href=&quot;http://en.wikipedia.org/wiki/Ussher_chronology&quot;&gt;Ussher Chronology&lt;/a&gt; (which provides probably the most famous biblically-based estimate of the Earth's age) goes into reasonable detail about the methods used for such calculations.&lt;/p&gt;&#xA;" OwnerUserId="94" LastActivityDate="2015-05-08T18:32:06.640" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4843" PostTypeId="5" CreationDate="2015-05-08T21:43:40.287" Score="0" Body="&lt;p&gt;See also &lt;a href=&quot;http://www.wrf-model.org&quot; rel=&quot;nofollow&quot;&gt;WRF homepage&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2015-05-09T12:03:53.857" LastActivityDate="2015-05-09T12:03:53.857" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4844" PostTypeId="4" CreationDate="2015-05-08T21:43:40.287" Score="0" Body="The Weather Research &amp; Forecasting Model" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2015-05-09T12:03:26.287" LastActivityDate="2015-05-09T12:03:26.287" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4845" PostTypeId="2" ParentId="4825" CreationDate="2015-05-09T02:28:41.070" Score="7" Body="&lt;p&gt;&lt;strong&gt;No, you can't stop an earthquake with a nuclear weapon. You can't even start one.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You asked if you could &quot;obliterate a plate&quot; with a nuclear explosion. Definitely not. Plates are between about 10 and 100 km thick, and as you can see from this map, &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_tectonic_plates&quot; rel=&quot;noreferrer&quot;&gt;the earth's 15 large plates&lt;/a&gt; are very large indeed:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/DWe7c.gif&quot; alt=&quot;Tectonic plates on earth&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see at the pockmarked &lt;a href=&quot;https://en.wikipedia.org/wiki/Nevada_Test_Site&quot; rel=&quot;noreferrer&quot;&gt;Nevada Test Site&lt;/a&gt;, nuclear weapons really don't make much of a dent by comparison — these craters are about 200 m across: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/xMTyR.jpg&quot; alt=&quot;Nevada Test Site craters&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One might expect that a large explosion could &lt;em&gt;cause&lt;/em&gt; an earthquake, but there's no real evidence for that either. Here are Goldblatt &amp;amp; Cox (1988, Oxford) in &lt;em&gt;Nuclear Weapon Tests: Prohibition or Limitation?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/BIjzg.png&quot; alt=&quot;Goldblatt &amp;amp; Cox excerpt&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that we're not talking about triggering surface waves that a person might feel — nuclear explosions definitely do that. This is about causing a fault movement or rock fracture. Goldblatt &amp;amp; Cox are saying that the explosive strain is too small and too transient — that is, temporary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems beyond belief that a large detonation very close (within a few kilometres?) to a shallow, 'locked' fault, past due for an earthquake so to speak, could not trigger an earthquake, but I can't find any record of this having happened... maybe someone can unearth something. &lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-05-09T02:28:41.070" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4846" PostTypeId="2" ParentId="4839" CreationDate="2015-05-09T16:05:21.693" Score="6" Body="&lt;p&gt;Volcanoes erupt due to increase in pressure, within the magma chamber (often 3-10 km deep), due to exolusion of volatiles. The magma chamber is usually heated from below. Geothermal plants in volcanic regions exploit heat from hot water in the &quot;shallow subsurface&quot;, few hundreds of meters deep (and rarely exceeding 1-2 km). So as far as your second last question is concerned the impact on the volcano will be little as deep hydrothermal circulation can only transport so much heat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are many such plants around the world, e.g., Iceland, Philippines, Indonesia, New Zealand etc. However drilling in hot rocks has its own set of problems. It is also not easy to build large plants near volcanic areas due to lack of accessibility, infrastructure, market etc.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastActivityDate="2015-05-09T16:05:21.693" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4847" PostTypeId="2" ParentId="4839" CreationDate="2015-05-10T00:57:57.977" Score="3" Body="&lt;p&gt;The question is a little off the mark, as volcanoes are just the surface expression of a much larger system. A more general idea is to target shallow magma chambers, and the hydrothermal fluids they act upon. This is being done all over the world, in tectonically active areas where there is a lot of molten rock at reasonably shallow depths. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Iceland Deep Drilling Project have accidentally created the first magma-EGS system. Read more: pangea.stanford.edu/ERE/db/WGC/papers/WGC/2015/37001.pdf &lt;/p&gt;&#xA;" OwnerUserId="61" LastActivityDate="2015-05-10T00:57:57.977" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4848" PostTypeId="1" AcceptedAnswerId="4849" CreationDate="2015-05-10T07:18:51.390" Score="16" ViewCount="30754" Body="&lt;p&gt;From my research, there is lots of information on how to extract ore, but I can't find any information on how these ore deposits are found in the first place, apart from 'looking for surface formations'. So, what kind of formations would exist for different types of ore? Are there any other ways of finding ore? &lt;/p&gt;&#xA;" OwnerUserId="2891" LastEditorDisplayName="user20559" LastEditDate="2021-05-12T10:38:18.787" LastActivityDate="2021-05-12T10:38:18.787" Title="How do geologists find ore deposits?" Tags="|geology|mineralogy|minerals|economic-geology|ore|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4849" PostTypeId="2" ParentId="4848" CreationDate="2015-05-10T08:44:57.703" Score="19" Body="&lt;p&gt;That is the multimillion dollar question! &quot;looking for surface formations&quot; is indeed one way, and it was the main method of exploration in the past. This does not necessarily mean that you directly see the ore deposit in front of your eyes. Many ore-forming systems are accompanied by different kinds of alteration (for example potassic or argillic alteration) that are not too hard to see in the field. Once you see them, there is a possibility that an ore deposit is nearby. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other surface methods include, among others, looking at rivers sediments. Since rivers transport soils and rocks from upstream, sampling the sediments may reveal an anomaly in a certain commodity of interest that may lie somewhere upstream. It is also possible to use satellite data - by looking at certain wavelengths it is possible to estimate the mineralogical composition of the surface. This may give hints on the possibility of mineralisation. I've even seen cases where people used different kinds of vegetation that grows on different lithologies!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Surface methods, however, require that the mineralisation will be close to the surface, and the truth is that most of the ore deposits that satisfy that requirement have already been found. This is where geophysical methods come into place. Gravimetric, magnetic and seismic studies probe the earth below the surface and may provide exploration targets, which are then drilled to see what's actually in there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mineral exploration is a hard business with much more failures than successes. That said, cases of serendipity are not unknown in exploration. Also, changes in global economics, production costs and increasing/decreasing metal prices may change what is actually an economically feasible ore deposit. The metals are always there - but is it actually worth taking them out?&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-05-10T08:44:57.703" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4851" PostTypeId="2" ParentId="4705" CreationDate="2015-05-11T16:02:23.463" Score="2" Body="&lt;p&gt;As noted in the comments, this is actually a much more complex question than it might seem at first. Answering fully would require a very involved and technical discussion of single-beam surveying's inherent errors and their causes (water velocity, side slope reflection, highly transmissive hydrocarbon-rich anthropocene silt, and other such complications). I will skip those topics—thankfully, I think—and simply focus on the OP's question of what errors Posidonia sea grass might introduce to a hypothetical singlebeam survey. As such this may be more of a partial answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's say you're using a singlebeam instrument with a fairly narrow pulse angle, like 3º. (Your vessel should not roll too much with this narrow a beam, but it will give higher resolution). You're surveying over a colony of Posidonia on a flat seabed. Posidonia leaves have a density fairly similar to that of the water column. Depending on the frequency of sound you are surveying with, you may get a ping with a slightly different shape from surveying over an area of &quot;bare ground&quot;. This is, at least in theory, due to the slight variation in density between the water column and Posidonia leaf blades causing small amounts of reflection and refraction to the sound wave before it hits the root mat and the top of sediment. Just for imagination's sake, I've included the conceptual &quot;bare ground&quot; model below.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/gxJSr.gif&quot; alt=&quot;Behavior of P-waves and S-waves at a impedance change boundary&quot;&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Behavior of P-waves and S-waves at a impedance change boundary. Image reproduced from &lt;a href=&quot;http://tle.geoscienceworld.org/content/24/Supplement/S46.full&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dragoset, B., &lt;em&gt;A historical reflection on reflections&lt;/em&gt;, The Leading Edge, 2005, v. 24, p. S46-S71&lt;/a&gt;, Box 1.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A good singlebeam acquisition program will allow you to choose the method of bottom tracking. Often these methods are not associated with the first return but rather the &quot;strongest&quot; part of the first return within some specified distance from the last known bottom position. This allows the minimization of error created by, for example, fish swimming in the path of the beam (see image below), and also the weaker first returns of soft vegetation.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/MvEfG.jpg&quot; alt=&quot;Fish in the water column as seen during a singlebeam survey&quot;&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Fish in the water column as seen on a singlebeam survey. A red band indicates the strongest return amplitude. An acquisition program would likely classify the bottom at or near the top of the red band. Image reproduced from the &lt;a href=&quot;http://ccom.unh.edu/gebco2013/data_processing.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;University of New Hampshire Ongoing Education website&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, if we assume that the acquisition program's bottom tracking capability is acceptable, the errors that Posidonia's leaves introduce will be minuscule, because the leaves do not present a large change in impedance and thus will not reflect much of the beam. You're left with deciding whether or not you want to classify the &quot;bottom&quot; of the water column as Posidonia's root mat, which may be several inches thick in a large colony, or the top of the sediment below. This is where your uncertainty will likely lie. What I don't know, and what may be difficult to figure out without some rather clinical testing, is whether or not the root mat provides a strong-enough first return to trigger the bottom tracking. I suspect it would, but I can't say that with any confidence without looking at a controlled test survey. I imagine companies like &lt;a href=&quot;http://odomhydrographic.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Odom&lt;/a&gt; and &lt;a href=&quot;http://www.km.kongsberg.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kongsberg&lt;/a&gt; do this regularly and might be able to give you a more specific answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tobbe also correctly notes that lower frequencies won't be affected as much by vegetation as higher frequencies. If you were going to try to run a bathymetric survey over Posidonia—or any area with high concentrations of seafloor plant life—you would want to consider using a device capable of lower frequency surveys...at the cost of diminishing your resolution.&lt;/p&gt;&#xA;" OwnerUserId="2749" LastActivityDate="2015-05-11T16:02:23.463" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4856" PostTypeId="2" ParentId="139" CreationDate="2015-05-11T19:19:51.023" Score="4" Body="&lt;p&gt;This may not answer your question to your liking but there is &lt;a href=&quot;http://geofaculty.uwyo.edu/heller/Papers/McMillanGSA06.pdf&quot; rel=&quot;nofollow&quot;&gt;fairly relevant research&lt;/a&gt; on the topic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think there is still a debate about the causes of the recent (Late Cenozoic) uplift, however. The current &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2006JF000557/abstract&quot; rel=&quot;nofollow&quot;&gt;dominant theory&lt;/a&gt; relates the shallow subduction of the Farallon Plate to subcontinental delamination and increased bouyancy all the way to the Front Range (see @Tbb's answer).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This theory essentially states that tectonic forcing is mimicked and in a sense bolstered by incisional unloading and subsequent depositional loading between the two landforms (montane vs. high plains). There has been a lot of research on erosion rates in the Eastern Rockies to test parts of Anderson's theories. It seems that most of the research I remember from learning about this problem in college is not freely available, but the papers in the links above have good summaries and discussions of the tectonic forcing and incision-based hypothesis.&lt;/p&gt;&#xA;" OwnerUserId="2749" LastEditorUserId="2749" LastEditDate="2016-05-02T19:20:29.437" LastActivityDate="2016-05-02T19:20:29.437" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4857" PostTypeId="2" ParentId="4848" CreationDate="2015-05-11T19:28:58.553" Score="13" Body="&lt;p&gt;In addition to the above, what happens is that people look for commonalities between known deposits. So, for example, if you have a lot of gold veins in one area, and lots in another area, then you look at what is needed for these veins to form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once you have a reasonable idea of possible ways to form your ore, then you have something that you can look for. Maybe the gold is associated with granite of a particular age range or with particular trace element composition? So if you go somewhere else, and find granite of the right age and trace element composition, then you have a reason to suspect that there might be gold veins in the area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This methodology is why you will often hear about &quot;types&quot; of deposit. Often these are named after a particularly prominent type-example, such as &lt;a href=&quot;https://en.wikipedia.org/w/index.php?title=Mississippi_Valley-Type&quot;&gt;Missisipi Valley Type deposits for Pb and Zn&lt;/a&gt;. Others are named after important features that are present within the deposit, such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Iron_oxide_copper_gold_ore_deposits&quot;&gt;Iron Oxide Copper Gold deposits&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can therefore narrow down what and where you might find things, and use all the stuff that @Michael mentioned in his answer as tools.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope that this also helps some.&lt;/p&gt;&#xA;" OwnerUserId="2514" LastEditorUserId="2749" LastEditDate="2015-05-11T20:05:15.143" LastActivityDate="2015-05-11T20:05:15.143" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4858" PostTypeId="1" CreationDate="2015-05-11T20:05:40.953" Score="8" ViewCount="162" Body="&lt;p&gt;I have been trying to figure out solution for the fourth order differential equation of flexure for a viscous plate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fourth order differential equation for a viscous plate is given as&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$Dv*\dfrac{\partial^4}{\partial x^4}\bigg(\dfrac{\partial w}{\partial t}\bigg) + kw = 0,$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;here, $Dv$ is a function of viscosity and elastic thickness, and $k$ is the specific weight. &#xA;My solution so far is &#xA;$$w = w_0*\exp(t/b)*\exp(-x/\alpha)*\cos(x/\alpha),$$ &#xA;where, $w_0$ is the maximum deflection, $b$ is function of $Dv$, $k$ and $\alpha$; and $\alpha$ is function of $Dv$ and $k$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem with my derivation is I am not sure if it correct and I do not have a way to check it. Moreover, the $b$ term is an issue as it resolves to constant integer, which is not physically likely.&#xA;Anyone out there, who could help me get on the right path? Any papers, any links?&lt;/p&gt;&#xA;" OwnerUserId="2894" LastEditorUserId="64" LastEditDate="2015-05-12T13:27:30.350" LastActivityDate="2016-03-12T03:37:01.243" Title="Flexure of a viscous lithosphere - derivation" Tags="|geophysics|geodynamics|lithosphere|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4859" PostTypeId="1" AcceptedAnswerId="4862" CreationDate="2015-05-12T08:24:35.507" Score="12" ViewCount="1805" Body="&lt;p&gt;Synthetics are generated by convolving reflectivity series with the known wavelet. I have seen most of the wavelet are extracted from seismic data itself. Is there any hard and fast rule, or can one extract wavelet from well log as well? If so which gives better result in terms of correlation? The wavelet extracted from seismic or well log data?&lt;/p&gt;&#xA;" OwnerUserId="2662" LastEditorUserId="28050" LastEditDate="2015-05-12T14:21:59.977" LastActivityDate="2015-05-12T15:36:06.907" Title="Should one extract wavelet from seismic or well log for the generation of synthetic traces?" Tags="|geophysics|seismology|waves|inversion|wave-modeling|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4860" PostTypeId="1" AcceptedAnswerId="4861" CreationDate="2015-05-12T08:35:53.057" Score="9" ViewCount="176" Body="&lt;p&gt;In constrained model based inversion, block size (in ms) is one of the inversion parameters. Specifying the block size value in the software divides the pseudo-velocity log into that number of layers or blocks. A smaller block size means higher resolution but that doesn't mean that one should specify smallest value because sometimes inversion result gets unstable. So how should one assign the block size parameter in model-based inversion? &lt;/p&gt;&#xA;" OwnerUserId="2662" LastEditorUserId="28050" LastEditDate="2015-05-12T14:20:18.717" LastActivityDate="2015-05-12T14:20:18.717" Title="How should I choose the block size in constrained model-based inversion?" Tags="|geophysics|models|inversion|wave-modeling|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4861" PostTypeId="2" ParentId="4860" CreationDate="2015-05-12T14:18:46.130" Score="5" Body="&lt;p&gt;&lt;strong&gt;It depends.&lt;/strong&gt;&amp;#8224;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some factors to consider:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;The sample interval of your seismic data.&lt;/strong&gt; there's not a lot of point in being smaller than that. For most legacy data it's 4 ms; these days it's often 2 ms. This is a lower bound; you can increase from here if your data have limited bandwidth; there's no point using less than 8 ms for data that's just noise past 50 Hz.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;What is the scale of your problem?&lt;/strong&gt; If this is part of an exploration exercise and the model is areally large, then you can safely and justifiably lose temporal resolution. If it's a reservoir characterization problem, then there's probably some feature you really care about: minor reservoir units, thin heterogeneities, etc. &lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;How much time have you got?&lt;/strong&gt; Small samples means more compute time, more statistics, more fiddling with details. It also means more time to simulate later, if you're doing flow modeling. Since you will no doubt end up doing everything multiple times, you need a model that is both useful and iterable.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I think there are at least a couple of approaches that avoid having to choose now and stick with it:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Start large, figure out the workflow, then reduce the size and watch the stability. Iterate until you have the right combination of detail, stability, and convenience.&lt;/li&gt;&#xA;&lt;li&gt;Model the big picture at low resolution, and more interesting subsets of the data at high resolution. Make the large interval an integer multiple of the small to facilitate merging them later.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Note that some properties, such as velocity, are scale-dependent. Be careful how you upscale them. Read up on Backus averaging, starting with &lt;a href=&quot;http://seismosblog.blogspot.ca/2014/06/backus-averaging-and-q.html&quot;&gt;Chris Liner's recent work&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&amp;#8224; How's that for a geoscientists's answer?&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-05-12T14:18:46.130" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4862" PostTypeId="2" ParentId="4859" CreationDate="2015-05-12T15:36:06.907" Score="7" Body="&lt;p&gt;&lt;strong&gt;Seismic, but...&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are lots of ways of estimating wavelets. None of them rely on well logs alone, because they don't contain any information about the wavelet. Some methods are purely statistical, some use the seismic data, and some of them use seismic and well logs.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Background&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;I recommend reading what you can about wavelet extraction. Especially these (&lt;a href=&quot;http://subsurfwiki.org/wiki/Must-read_geophysics#Interpretation&quot;&gt;see links to many of these here&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Brown, A (2001). Calibrate yourself to your data! A vital first step in interpretation. &lt;em&gt;Geophysical Prospecting&lt;/em&gt; 49, p 729–733.&lt;/li&gt;&#xA;&lt;li&gt;Roden, R and H Sepulveda (1999). The significance of phase to the interpreter: practical guidelines for phase analysis. &lt;em&gt;The Leading Edge&lt;/em&gt; 18, July 1999, p 774–777.&lt;/li&gt;&#xA;&lt;li&gt;Simm, R and R White (2002), Tutorial: Phase, polarity and the interpreter's wavelet. &lt;em&gt;First Break&lt;/em&gt; 20 (5), p 277–281.&lt;/li&gt;&#xA;&lt;li&gt;White R, and R Simm (2003). Tutorial: Good practice in well ties. &lt;em&gt;First Break&lt;/em&gt; 21 (10), p 75–83.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h3&gt;Workflow&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;My approach, for what it's worth, is as follows:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Establish that your seismic data are zero phase. See &lt;a href=&quot;http://subsurfwiki.org/wiki/Phase_determination&quot;&gt;this wiki article&lt;/a&gt; and &lt;a href=&quot;http://library.seg.org/doi/abs/10.1190/tle33101164.1&quot;&gt;this tutorial&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Tie your wells with a purely statistical zero-phase wavelet until you know better. A &lt;a href=&quot;http://subsurfwiki.org/wiki/Ricker_wavelet&quot;&gt;Ricker&lt;/a&gt; is fine for most impulsive data. Don't bother with autocorrelation. Don't bother with mixed-phase. Once you've found the best one, don't change it from well to well.&lt;/li&gt;&#xA;&lt;li&gt;Take your best well ties (maybe the best 10 or 20 percent), and check them.&lt;/li&gt;&#xA;&lt;li&gt;Try extracting zero-phase wavelets from your best data, preferably near angle stack, and unfiltered (e.g. by &lt;em&gt;fk&lt;/em&gt;, which processors love) &amp;mdash; you don't want any spectral shaping nonsense. Only use the zone of interest, but at least about 1000 ms of data. Avoid the near surface.&lt;/li&gt;&#xA;&lt;li&gt;Average all the wavelets you got and tie all your wells with this wavelet. The ties should improve in most cases.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Note: Step 4 usually involves estimating the wavelet from the seismic data, using the reflectivity from the wells. It's basically the reverse of making a synthetic: &lt;code&gt;seismic / reflectivity = wavelet&lt;/code&gt;, where &lt;code&gt;/&lt;/code&gt; denotes deconvolution.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;&lt;em&gt;Caveat interpretor&lt;/em&gt;&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;I would complete the workflow for each seismic survey (e.g. a 3D, or all lines in a 2D). Your goal is to use a single wavelet for each survey. This goal reflects the assumptions in this workflow:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The reflectivity is random.&lt;/li&gt;&#xA;&lt;li&gt;The wavelet is zero-phase or minimum-phase.&lt;/li&gt;&#xA;&lt;li&gt;The wavelet is stationary (invariant in space and time).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;None of these assumptions hold (Ziolkowski, 1991; Why don’t we measure seismic signatures? &lt;em&gt;Geophysics&lt;/em&gt; 56, 190–201; &lt;a href=&quot;http://www.crewes.org/ResearchLinks/GraduateTheses/1999/Dey-MSc-1999.pdf&quot;&gt;see also this thesis&lt;/a&gt;). This is what makes it fun! Your job is to cope with this without breaking the laws of physics or what we know about geology.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-05-12T15:36:06.907" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4863" PostTypeId="2" ParentId="4858" CreationDate="2015-05-13T04:25:09.557" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The problem with my derivation is I am not sure if it correct and I do not have a way to check it.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Try dimensional analysis to check your solution. Is your solution consistent with dimensional analysis? Estimate a solution to a real example, based upon you knowledge of geophysics and geology. Does your solution even come close to a reasonable estimate? If you are unfamiliar with dimensional analysis and estimation methods, I recommend the online book (MIT course) &lt;a href=&quot;http://ocw.mit.edu/courses/mathematics/18-098-street-fighting-mathematics-january-iap-2008/readings/sf_math.pdf&quot; rel=&quot;nofollow&quot;&gt;Street Fighting Mathematics&lt;/a&gt; for some possible ways to stimulate ideas of ways to check your derivation.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, as you have written your solution, the $b$ and the $\alpha$ are constant over time ($t$) and location ($x)$. First substitute your solution into the differential equation, and carry out the differentiation to confirm that it is in fact a solution. If it can be verified as a solution, turn your attention to the dimensions of b and alpha. The dimension of b must be time and the dimension of alpha must be length. You are modeling the system as a viscoelastic solid, so the the initial condition ($t=0$) for your displacements $w(0,x)$ are just the elastic solution, and the time-dependent term is unity. Use the elastic solution to solve for alpha (the characteristic wavelength) because this does not change over time. Name the purely elastic displacement '$e$' and it has dimension of length. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You know you want to include viscosity somewhere, so let's try the kinematic viscosity $v$ (dimensions $M*M/s$). So try $b = -(L * L)/v$, or $b = -(L * 1)/v$, because this is a 2D problem and can be one unit deep. You'll need the negative sign to make the displacement grow faster for a smaller viscosity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What could $L$ be? I would try $L=e$, or $L=e/2$. Because you really don't know the kinematic viscosity of the lithosphere, the factor is not critical. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Substitute $b$ and $\alpha$ into your solution. Does the result seem to make physical and geological sense? &lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorUserId="20" LastEditDate="2016-03-12T03:37:01.243" LastActivityDate="2016-03-12T03:37:01.243" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4864" PostTypeId="1" CreationDate="2015-05-13T05:17:36.087" Score="11" ViewCount="200" Body="&lt;p&gt;I don't know what &lt;a href=&quot;https://www.youtube.com/watch?v=SwUjAKL0HiE&quot;&gt;this YouTube video&lt;/a&gt; shows, but it appears to be half glacier and half &quot;the blob.&quot; It almost appears to be &quot;growing&quot; although I assume it's being pushed somehow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can someone tell me what this is called, what causes it, and how common it is?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Warning: Strong language in the video.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="2899" LastEditorUserId="28050" LastEditDate="2015-05-13T14:00:44.987" LastActivityDate="2015-05-14T11:02:05.457" Title="What ice phenomenon are we seeing in this video?" Tags="|meteorology|geophysics|water|ice|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4865" PostTypeId="2" ParentId="4864" CreationDate="2015-05-13T10:13:35.030" Score="7" Body="&lt;p&gt;It's called &lt;a href=&quot;http://en.wikipedia.org/wiki/Ice_shove&quot; rel=&quot;nofollow&quot;&gt;ice shove&lt;/a&gt;. Ice on the lake melts whiles the wind push and pile the thin sheets ashore. I don't know how common it is but I've seen it in much smaller scale in European lakes. However, this occasion made it to the &lt;a href=&quot;http://usnews.nbcnews.com/_news/2013/05/12/18213239-giant-sheets-of-ice-creep-onto-minnesota-shore-surge-toward-houses?lite&quot; rel=&quot;nofollow&quot;&gt;news&lt;/a&gt;. It does indeed look rather spectacular! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fresh water of the Great Lakes in combination with &lt;a href=&quot;http://www.ijc.org/en_/blog/2014/03/14/great_lakes_polar_vortex_2013_14/&quot; rel=&quot;nofollow&quot;&gt;cold air&lt;/a&gt; often create beautiful and &lt;a href=&quot;http://mynorth.com/wp-content/uploads/2013/03/ice-coated-boat-in-great-lakes.jpg&quot; rel=&quot;nofollow&quot;&gt;photogenic&lt;/a&gt; art. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2015-05-14T11:02:05.457" LastActivityDate="2015-05-14T11:02:05.457" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4866" PostTypeId="2" ParentId="4864" CreationDate="2015-05-14T06:50:52.630" Score="8" Body="&lt;p&gt;This phenomenon goes by a number of names: ice heave, ice shove, ice creep, ice tsunami, and I'm sure there are others. It is a consequence of the spring ice breakup coupled with strong sustaining winds on large northern lakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The warming spring weather melts the ice close to shore first, making the ice on the lake free-floating. The ice in the middle of the lake can still be close to a meter thick. Winds jostle the ice around, breaking it into chunks. With strong sustaining winds, the ice moves toward the downwind shore. With even stronger sustaining winds, the shoreline is not enough to stop the ice from moving onshore. The ice from further out (and this ice can be very thick) pushes the ice ashore, sometimes bulldozing trees and buildings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a playlist of 19 youtube videos that portray this phenomenon: &lt;a href=&quot;https://www.youtube.com/watch?v=0EyfEDKWscg&amp;amp;list=PLPHgakWET6JeATJ1duoGkYItCvfPl26FU&quot;&gt;https://www.youtube.com/watch?v=0EyfEDKWscg&amp;amp;list=PLPHgakWET6JeATJ1duoGkYItCvfPl26FU&lt;/a&gt; . At 32 seconds into the fifth video in the playlist you can see how thick some of the slabs of ice are.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-05-14T06:50:52.630" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4867" PostTypeId="2" ParentId="694" CreationDate="2015-05-14T09:08:05.020" Score="4" Body="&lt;p&gt;The advantage of SEGY is also it's main problem; It's been around for very long. I've been struggling to open a decade old word document correctly, whiles one can actually still access a SEGY from the 70's or 80's. It's also an advantage that all program packages can, somehow, import and export the files. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I agree with David, that the headers doesn't need to be in the same file as the data. I'd prefer to have the trace headers readable as ASCII files whiles the data can be binary, but preferable standardized or at least defined in the header. ASCII trace headers are also easy to import for GIS applications, SQL or spreadsheets. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://www.ahay.org/wiki/Guide_to_RSF_file_format&quot; rel=&quot;nofollow&quot;&gt;rsf&lt;/a&gt; format (developed from SEPlib), could have been exactly what I was looking for, but trace headers are not written to the header file, but instead placed in separate files. This is not bad for the processing workflow, but it makes it difficult to export files. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The perfect solution, from my limited experience, would be something like a rsf file, with file header and trace headers in the same .rsf. I've been suggesting it to some fellow Madagascar users, and the argument against it is that in large projects the header file would be very (too) large. However, I don't see that as a problem, rather another argument to have the trace headers in an easy searchable and as far as I know there are no limitations of ascii files size. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2015-05-17T09:15:14.710" LastActivityDate="2015-05-17T09:15:14.710" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4868" PostTypeId="1" AcceptedAnswerId="4870" CreationDate="2015-05-15T02:16:01.900" Score="9" ViewCount="298" Body="&lt;p&gt;I'm trying to make use of &lt;a href=&quot;http://www.ngdc.noaa.gov/mgg/global/global.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;the ETOPO1 dataset&lt;/a&gt; as the bathymetry input of a wave model. I came upon this discussion of grid registration: &lt;a href=&quot;http://www.ngdc.noaa.gov/mgg/global/gridregistration.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Registration of Structured Square-Cell Grids&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I read this material several times and I'm still confused about some things. From what I understand of the diagram on that page: the blue dots represent the data values. We know from the dataset what the latitude and longitude of each of the blue dots is. And for each blue dot, it is always in the center of the cell, which is the area it represents. If I'm right so far, what is the difference or significance of these two schemes? What is the purpose of the red lines? Why might there be an ambiguity, since we already know the locations of the blue dots and the data values at those locations? Does it affect how we interpret the data? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If anyone can help me with this, or point me to relevant resources, it would be much appreciated.&lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorUserId="725" LastEditDate="2016-12-31T06:59:16.453" LastActivityDate="2017-01-01T22:31:12.530" Title="Confusion about grid registration concepts and their relevance in modelling" Tags="|models|numerical-modelling|bathymetry|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4869" PostTypeId="2" ParentId="4868" CreationDate="2015-05-15T09:03:16.783" Score="3" Body="&lt;p&gt;&lt;em&gt;Disclaimer: I have no special knowledge of this data set. But from reading the linked page, which I agree is not very clear, here's my understanding:&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you have stated, the data points actually represent cells with a finite area rather than points. The difference between the two approaches is whether the location of the cell is identified by giving the coordinates of the cell centre (shown by the blue dot), or of one corner of the cell.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To put it another way - the lat/lon coordinates that you have may not correspond with the locations of the blue dots, but be half a cell offset from them.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2015-05-15T09:03:16.783" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4870" PostTypeId="2" ParentId="4868" CreationDate="2015-05-15T12:09:27.623" Score="11" Body="&lt;p&gt;&lt;strong&gt;Yes, it makes a difference. In this case the grid-registered dataset is higher fidelity. However, the cell-registered is easier to handle.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you see, both types of data are available &lt;a href=&quot;http://www.ngdc.noaa.gov/mgg/global/global.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;on the dataset's page&lt;/a&gt;. The page states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The grid-registered is the authoritative registration.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The page also points out:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The cell-registered is derived from the grid-registered,&#xA;  and the conversion produces slightly flattened relief.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So what's the difference? The grid-registered version puts the data points at the grid corners (the red lines, not the grey squares, define the grid boundaries. You have to imagine the grid cells in the left-hand image). So if there are $n \times m$ grid cells, there are $(n+1) \times (m+1)$ data points in the grid-registered data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since there are fewer data points in the cell-registered version, making it involves some smoothing (averaging) of the values in the grid-registered version. There's an illustration of this effect on &lt;a href=&quot;http://www.ngdc.noaa.gov/mgg/global/gridregistration.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;the other page&lt;/a&gt; you linked to; notice how the centre cell of value 90 ends up being smoothed away:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/xksX8.gif&quot; alt=&quot;Flattening grids&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;So if accuracy is paramount, you should use the grid-registered version.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;But...&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;You might find cell-registered data more convenient to work with (for me at least it's more intuitively analogous to an image).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The catch is that if you have grid-registered but accidentally treat it as cell-registered, then the data will shift by half a cell. So you should keep careful track of what kind of data you have. As the NOAA page states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Most grid applications recognize both types and avoid [the grid shift]&#xA;  problem but care should be taken.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Indeed, one popular open source GIS tool, &lt;a href=&quot;http://grass.osgeo.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;GRASS&lt;/a&gt;, apparently only handles cell-registered data, &lt;a href=&quot;http://grasswiki.osgeo.org/wiki/Grid_registration&quot; rel=&quot;nofollow noreferrer&quot;&gt;as explained in the GRASS wiki&lt;/a&gt;. So after loading (to wherever) you should check where the pixels of the raster actually end up.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2015-05-15T12:31:01.207" LastActivityDate="2015-05-15T12:31:01.207" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4871" PostTypeId="2" ParentId="4848" CreationDate="2015-05-15T18:24:41.427" Score="11" Body="&lt;p&gt;I've been looking for these things over a few decades and along with other geologists doing this we have seen how we find things change somewhat.  Many methods used a century ago are still in use, but with the addition of refinements. So looking at how large and small deposits were found will change over time. (Simple example of that would be that Romans and their contemporaries didn't use geophysics, but they did find major copper deposits in Spain.)  Deposits are getting harder to find.  It has been estimated that &lt;a href=&quot;https://books.google.nl/books?id=MjkqBAAAQBAJ&amp;amp;pg=PA6&amp;amp;lpg=PA6&amp;amp;dq=most+major+outcrops+in+the+world+has+been+visited+by+a+competent+geologist&amp;amp;source=bl&amp;amp;ots=VmFYxutpqK&amp;amp;sig=wbDZ0K-VMLA8elZcZa3tMzg6zF8&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwjN4YaApLLPAhWK1RoKHWh3As4Q6AEIHjAA#v=onepage&amp;amp;q=most%20major%20outcrops%20in%20the%20world%20has%20been%20visited%20by%20a%20competent%20geologist&amp;amp;f=false&quot; rel=&quot;nofollow&quot;&gt;&quot;most major outcrops in the world have been visited by a competent geologist&quot;&lt;/a&gt;.&lt;sup&gt;*&lt;/sup&gt;&lt;br /&gt;&#xA;But I must admit, I spend enough time in remote locations to question the statement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Give prospectors credit for going out and banging on rocks.  I know this sounds simplistic but prospectors did develop good intuition about where to look even though they did not apply the genetic models we like to work with today.  Ultimately, getting out in the field and seeing what you could find was key.  There were also a lot of part time prospectors who were primarily out to hunt or trap.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It takes several rounds (or companies) to usually find a deposit.  They are hard to find, and typically you run out of investment and luck before that happens.  There are various estimates on how many tries it takes on average, but looking at prospective areas where there have been several in there before you is not a bad idea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A third thing that can help is revisiting an area that was previously abandoned for a reason other than geology.  This could be a small mine that lost its workers to natural disasters, wars or other economic conditions.  The previous work may have stopped because the exploration was in the &quot;too hard&quot; category.  This is good areas to revisit - particularly in improvements in technology have opened new geochemical or geophysical methods that can tip the balance from too hard.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I throw these three things into &quot;how to find deposits&quot; because even though they are not specific technical methods, they are very much the kind of things exploration geologists think about when selecting areas to use their resources.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;* In: Achterberg, F. - &lt;em&gt;Geomathematics: Theoretical Foundations, Applications and Future Developments&lt;/em&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="1396" LastEditorUserId="595" LastEditDate="2016-09-28T14:35:58.880" LastActivityDate="2016-09-28T14:35:58.880" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4872" PostTypeId="1" CreationDate="2015-05-15T23:02:19.660" Score="7" ViewCount="3568" Body="&lt;p&gt;The century old sustained rising of oceans, at a rate of 2-4 mm/y, remains a unexplained phenomenon; there is no correlation with temperature variations, so it is not due to the thermal variation of the volume of the oceans or to a decrease of Antarctic ice (which in fact is increasing).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A possibility, given that this raise of the oceans is not absolute but relative to coast, is that it is not the oceans’ absolute level that is raising but the continents that are sinking. A possible cause is global oscillations of the mantle surface level, and tectonic plates move up and down besides drifting.  Another cause is the solidification of the mantle under continental plates due to the decrease of Earth internal temperature. What do you think? Are the oceans rising or the continents going down (in average)? Only satellite measurements can solve the riddle? &lt;/p&gt;&#xA;" OwnerUserId="2905" LastEditorUserId="32" LastEditDate="2015-07-04T08:39:12.060" LastActivityDate="2021-02-21T16:59:31.470" Title="Are the oceans rising or the continents going down? How can we know?" Tags="|geophysics|oceanography|plate-tectonics|sea-level|geodynamics|" AnswerCount="5" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4873" PostTypeId="2" ParentId="4872" CreationDate="2015-05-16T01:29:50.790" Score="13" Body="&lt;p&gt;&lt;strong&gt;To the best of our knowledge, sea-level is rising because the volume of water is increasing.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is substantial local variation in sea-level change; &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4728/why-is-relative-sea-level-falling-in-hudson-bay&quot;&gt;it's falling in some parts of Canada&lt;/a&gt;. But of the dozens of controls on local and global sea-level, the net effect is currently an average global rise of about 3&amp;nbsp;mm/y. It's not really 'a riddle'. The phenomenon is well documented and there isn't too much mystery about the various causes. One could certainly debate their relative contributions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Satellites already contribute much of the data that reveals the sea-level rise (and the relative stasis of the continents), and that substantiates some of the causes. For example, the &lt;a href=&quot;https://en.wikipedia.org/wiki/TOPEX/Poseidon&quot; rel=&quot;nofollow noreferrer&quot;&gt;TOPEX&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Ocean_Surface_Topography_Mission&quot; rel=&quot;nofollow noreferrer&quot;&gt;Jason-2&lt;/a&gt; satellites, constrained by gauges on earth, &lt;a href=&quot;http://sealevel.colorado.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;are important sources of data&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Two prominent causes of sea-level rise are thermal expansion and ice loss (for example in Greenland), but &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2555/are-there-secondary-causes-of-sea-level-change&quot;&gt;there are lots of others&lt;/a&gt;. Tectonic plates do definitely move up and down — it's an important phenomenon in geology and geomorphology, and it does affect sea-level in all sorts of ways (see that link).&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-05-16T01:29:50.790" CommentCount="13" ContentLicense="CC BY-SA 3.0" />
  <row Id="4874" PostTypeId="1" AcceptedAnswerId="4875" CreationDate="2015-05-16T03:10:14.800" Score="19" ViewCount="1899" Body="&lt;p&gt;I have a physics/maths background, and to me the most convincing evidence of a scientific fact is often a very simple model that gives reasonable results. A simplified model, which you can fully understand, is often more convincing than the numerical output of a complex model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I'm looking for a &lt;em&gt;simple&lt;/em&gt; climate model, which could be used to predict how increasing $\ce{CO_2}$ concentrations would lead to an increase in temperature. For instance, this model need not account for the specific geography of the earth: it might just consider the sun's radiation passing through an atmosphere and striking a flat, homogeneous surface with some constant absorptivity. Then we could just do an energy balance to find equilibrium temperature as a function of $\ce{CO_2}$ concentration.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I could do a back-of-the-envelope calculation to see that doubling $\ce{CO_2}$ concentrations would be expected to increase the Earth's temperature by a few degrees (I expect nothing more than this order-of-magnitude evidence) then I think that would be convincing evidence that climate change is worth worrying about. You can argue with satellite data and complex models, but you can't argue with basic physics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far, the only source I've found that gives such a simplified model is Arrhenius himself, in his &lt;a href=&quot;http://www.rsc.org/images/Arrhenius1896_tcm18-173546.pdf&quot;&gt;1896 paper&lt;/a&gt;. I actually find his model quite convincing, and its prediction ($\sim5^oC$ increase from doubling $\ce{CO_2}$) gives a reasonable prediction too. However, his data on the absorptivity of the atmosphere was (rather quaintly) obtained by early measurements of the intensity of moonlight at different angles in the sky. While this is ingenious, I'm sure with modern technology we could get much better estimates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I'm basically looking for either a modernised version of Arrhenius' calculations, or alternatively another simple model which convincingly demonstrates that increasing $\ce{CO_2}$ has the power to alter the earth's temperature by as much as a few degrees. &lt;/p&gt;&#xA;" OwnerUserId="1017" LastEditorUserId="543" LastEditorDisplayName="user2872" LastEditDate="2018-01-13T03:55:30.347" LastActivityDate="2022-11-25T03:15:26.060" Title="Simple Climate Models that Predict Climate Change" Tags="|climate-change|climate|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4875" PostTypeId="2" ParentId="4874" CreationDate="2015-05-16T08:48:40.410" Score="18" Body="&lt;p&gt;It sounds like you are asking for a simple climate model that treats the globe as a homogeneous system.  A Zero-dimensional energy balance model may be of interest (see this &lt;a href=&quot;https://www.e-education.psu.edu/meteo469/node/137&quot; rel=&quot;noreferrer&quot;&gt;Penn State site&lt;/a&gt; ) which uses a starting point that is also basically described in this post: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2280/temperature-as-a-function-of-luminosity-and-greenhouse-gas-concentrations/2281#2281&quot;&gt;Temperature as a function of luminosity and greenhouse gas concentrations&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you solve for the temperature of the Earth using a blackbody approximation and thermal equilibrium (with an albedo of about 0.3), you are only taking into account the temperature of the Earth without a greenhouse effect (about 33 °C cooler than actual temperature).  It is very difficult to calculate the influence of infrared radiative forcing components (e.g. oxygen and carbon dioxide) to an empty atmosphere, since there are many biogeochemical/physical feedbacks in the climate system which are nonlinear.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, if you start with current temperature/concentrations, you can add terms that represent particular increases to the GHG concentrations.  Those terms are constantly being refined by the scientific community and are summarized in this &lt;a href=&quot;http://en.wikipedia.org/wiki/Radiative_forcing&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia article&lt;/a&gt; about Radiative Forcing (see the link to &lt;a href=&quot;http://en.wikipedia.org/wiki/Climate_sensitivity&quot; rel=&quot;noreferrer&quot;&gt;climate sensitivity&lt;/a&gt; at the bottom of the page).  This is a kind of &quot;back of the envelope&quot; modeling approach that most climate scientists use to discuss past and future influence of climate forcers, which can be very helpful when discussing the expected climate effects of various emissions/mitigation scenarios.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://en.wikipedia.org/wiki/Radiative_forcing&quot; rel=&quot;noreferrer&quot;&gt;Radiative Forcing&lt;/a&gt; article in Wikipedia says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Radiative forcing can be used to estimate a subsequent change in equilibrium surface temperature (ΔTs) arising from that radiative forcing via the equation:&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;$$\Delta T_s =~ \lambda~\Delta F$$&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;where λ is the climate sensitivity, usually with units in K/(W/m&lt;sup&gt;2&lt;/sup&gt;), and ΔF is the radiative forcing. A typical value of λ for CO&lt;sub&gt;2&lt;/sub&gt; is 0.8 K/(W/m&lt;sup&gt;2&lt;/sup&gt;), which gives a warming of 3K for a doubling of CO&lt;sub&gt;2&lt;/sub&gt; [from pre-industrial times, assuming RF of CO&lt;sub&gt;2&lt;/sub&gt; is ~ 3.7)].&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It's important to note that most climate sensitivity parameters and radiative forcing values are derived with respect to some time period (e.g. 1750 - 2011) and GHG feedbacks are set for a particular climate regime.  Revised radiative forcing and climate sensitivity parameters are needed to make calculations for other climate regimes.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The IPCC AR5 figure of Radiative Forcing components attributes 1.65 W/m&lt;sup&gt;2&lt;/sup&gt; to the actual increase in CO&lt;sub&gt;2&lt;/sub&gt; concentrations from 1750 to 2011 (or ~1.3K in temperature rise, if lambda is 0.8).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/uvf39.png&quot; alt=&quot;IPCC Summary for Policy Makers from IPCC AR5&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The values of Radiative Forcing that IPCC provides are likely close enough for doing realistic scenario testing.  However, something in an entirely different feedback regime would need very different parameters.  For instance, halving the CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere would have a much greater absolute effect on temperature than doubling it; temperature increases logarithmically as CO&lt;sub&gt;2&lt;/sub&gt; concentrations increase. This is because strong CO&lt;sub&gt;2&lt;/sub&gt; absorption bands are nearly saturated under present conditions, and increasing CO&lt;sub&gt;2&lt;/sub&gt; from present conditions mainly affects the flanks of the absorption bands.  However, water precipitates out of the system easily under low-temperature conditions, so CO&lt;sub&gt;2&lt;/sub&gt; has a much greater forcing value in those types of climate regimes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most difficult problems with testing simple climate scenarios are related to the oceans and the biosphere, which could have countless effects on the average climate and GHG regime.  &lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="725" LastEditDate="2017-05-12T14:45:47.780" LastActivityDate="2017-05-12T14:45:47.780" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4876" PostTypeId="1" CreationDate="2015-05-16T17:00:34.807" Score="14" ViewCount="8565" Body="&lt;p&gt;It seems as if the 'lowest energy' state for the Earth is to not have any mountains and that given enough time, the oceans would erode all land. Essentially it's an argument like entropy. And I mean in the &lt;em&gt;far&lt;/em&gt; future, once tectonic activity has ceased.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this the case, and if so how long might it take? If it is not the case, why not?&lt;/p&gt;&#xA;" OwnerUserId="2908" LastEditorUserId="81" LastEditDate="2022-03-30T21:10:24.233" LastActivityDate="2022-03-30T21:10:24.233" Title="Will the ocean eventually erode all land?" Tags="|oceanography|earth-history|erosion|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4878" PostTypeId="1" CreationDate="2015-05-16T18:57:43.430" Score="6" ViewCount="173" Body="&lt;p&gt;This article:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.seopanel.esforums.caves.orgwww.seopanel.esforums.caves.org/pub/journal/PDF/V60/V60N1-Anderson.pdf&quot; rel=&quot;noreferrer&quot;&gt;Anderson, C. H., C. J. Behrens, G. A. Floyd, and M. R. Vining. 1998. “Crater Firn Caves of Mount St. Helens, Washington.” Journal of Cave and Karst Studies 60: 44–50.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;discusses, among other things, density of the ice that forms the walls of the fumarolic ice caves in the crater of Mt St Helens.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The [St Helens summit crater] caves are called firn caves because their density ranges from 0.55 to 0.82 g/cm&lt;sup&gt;3&lt;/sup&gt;...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;but also:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The ice density in September 1994 at the base of this crevasse was 0.85 g/cm&lt;sup&gt;3&lt;/sup&gt;. The ice density in the lowest cave passage was 0.86 g/cm&lt;sup&gt;3&lt;/sup&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As far as I know, 0.86 is greater than 0.82. Right!?&lt;/p&gt;&#xA;" OwnerUserId="63" LastEditorUserId="28050" LastEditDate="2015-05-16T23:53:45.517" LastActivityDate="2015-05-16T23:53:45.517" Title="Is this article self-contradictory, or am I missing something?" Tags="|volcanology|glaciology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4879" PostTypeId="2" ParentId="4878" CreationDate="2015-05-16T21:06:18.547" Score="10" Body="&lt;p&gt;There's no contradiction. Firn is an intermediate form between snow and ice, with a density between that of snow and ice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The frozen fluffy stuff that falls from the sky -- that's not ice, it's not firn. It's snow. It's also not very dense, typically less than 0.5 grams/cm&lt;sup&gt;3&lt;/sup&gt;. As the snow sits and gets compressed by snow atop it, some of the gas gets squeezed out. The snow changes from ice to firn. The authors are using density between 0.55 and 0.82 grams/cm&lt;sup&gt;3&lt;/sup&gt; as the definition of firn. As the firn sits even longer, it changes from firn to ice. Note that solid frozen water (no air pockets whatsoever) has a density of about 0.934 grams/cm&lt;sup&gt;3&lt;/sup&gt;. Compressed former snow with a density of 0.82 or higher acts a lot like ice. It is ice, not firn.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-05-16T21:06:18.547" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4880" PostTypeId="1" CreationDate="2015-05-16T23:35:25.303" Score="8" ViewCount="93" Body="&lt;p&gt;The mean squared slope is a property of the sea surface that is often sensed by microwave radars &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/97JC02443/abstract;jsessionid=33BD51CD5995EF23CE34FCF0FAC31CBB.f01t01&quot;&gt;[1]&lt;/a&gt; &lt;a href=&quot;http://journals.ametsoc.org/doi/full/10.1175/1520-0426%282000%29017%3C1092%3ATMSSOO%3E2.0.CO%3B2&quot;&gt;[2]&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While spatial data for sea surface salinity, sea surface height, and significant wave height exist (Ex. &lt;a href=&quot;http://www.aviso.altimetry.fr/en/home.html&quot;&gt;[3]&lt;/a&gt; &lt;a href=&quot;http://podaac.jpl.nasa.gov/aquarius&quot;&gt;[4]&lt;/a&gt;), I've not been able to find spatial mean squared slope data, or wave spectrum data (from which mean squared slope can be derived). The only data I know of are from the &lt;a href=&quot;http://www.ndbc.noaa.gov&quot;&gt;National Buoy Data Center&lt;/a&gt;, but they are point measurements only.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm currently working on a microwave remote sensing project, and spatial mean squared slope data would prove to be helpful. Does anyone know if spatial mean squared slope or wave spectrum data exist anywhere?&lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorUserId="28050" LastEditDate="2015-05-16T23:43:36.753" LastActivityDate="2015-05-16T23:43:36.753" Title="Availability of mean squared slope or wave spectra data for the sea surface" Tags="|ocean|waves|open-data|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4881" PostTypeId="1" AcceptedAnswerId="5075" CreationDate="2015-05-17T11:51:03.400" Score="16" ViewCount="1249" Body="&lt;p&gt;The Giant's Causeway is, according to the &lt;a href=&quot;http://en.wikipedia.org/wiki/Giant&amp;#39;s_Causeway#Geology&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia page&lt;/a&gt; was formed during&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;during the Paleogene Period, Antrim was subject to intense volcanic activity, when highly fluid molten basalt intruded through chalk beds to form an extensive lava plateau.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Of particular note is the distinct columnar pattern (as seen in the picture below):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/YPcA8.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Formed, according to the Wikipedia page by&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;As the lava cooled, contraction occurred. Horizontal contraction fractured in a similar way to drying mud, with the cracks propagating down as the mass cooled, leaving pillarlike structures&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What was the geochemical/petrology process(es) cause the contraction features that resulted in the columns being formed in the Giant's Causeway?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user2872" LastEditorUserId="94" LastEditorDisplayName="user2872" LastEditDate="2017-01-31T21:10:02.113" LastActivityDate="2023-05-31T06:23:35.457" Title="What processes produced the basalt columns of the Giant's Causeway?" Tags="|geochemistry|volcanology|petrology|geomorphology|igneous|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4884" PostTypeId="1" AcceptedAnswerId="4890" CreationDate="2015-05-17T19:27:42.337" Score="11" ViewCount="804" Body="&lt;p&gt;I suppose natural gas underground caverns on Earth have substantial volume and gas is in gaseous form there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As such I wonder how it would look like inside such cavern (with artificial light of course). Will one see a rocky sky at big distance?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the actual volume of such caverns? It is correct to talk about methane oceans or seas?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are they empty or the gas is mixed up with solid substance?&lt;/p&gt;&#xA;" OwnerUserId="2819" LastEditorUserId="6129" LastEditDate="2020-05-05T16:07:08.360" LastActivityDate="2020-05-05T16:07:08.360" Title="What's it like inside a natural gas cavern on Earth?" Tags="|geology|gas|cavern|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4886" PostTypeId="2" ParentId="4884" CreationDate="2015-05-18T00:08:30.057" Score="4" Body="&lt;p&gt;&lt;a href=&quot;http://www.searchanddiscovery.com/pdfz/documents/2014/41427ishutov/ndx_ishutov.pdf.html&quot; rel=&quot;nofollow&quot;&gt;According to 3-D Printing Artificial Reservoir Rocks to Test Their Petrophysical Properties&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Pore sizes of typical reservoir sandstone range from 0.1 to 100s of microns.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="248" LastActivityDate="2015-05-18T00:08:30.057" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4887" PostTypeId="1" CreationDate="2015-05-18T05:28:18.833" Score="13" ViewCount="6556" Body="&lt;p&gt;I am asking this question in reference to the recent earthquake that struck Nepal last month. I read that the magnitude 7.8 richter scale earhtquake would have caused more damage had it lasted for longer time. In case of Nepal it lasted for nearly 30 seconds. I also read that that magnitude scale was not able to release all the energy that has been stored in the form of strain in the plate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what I wanted to ask is that if that earthquake had lasted for more time, would it have released more energy? Similarly does an earthquake of magnitude, say 6, would release energy just as equal to 7.8 if it lasted for more time?&lt;/p&gt;&#xA;" OwnerUserId="2915" LastEditorUserId="124" LastEditDate="2015-05-29T22:11:03.607" LastActivityDate="2015-05-29T22:11:03.607" Title="The relation between the magnitude and duration of earthquake" Tags="|geophysics|earthquakes|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4888" PostTypeId="1" CreationDate="2015-05-18T09:36:47.847" Score="8" ViewCount="180" Body="&lt;p&gt;I have looked at a few do it yourself remotely operated vehicles (ROV), and considered making one myself. However my research on the web has turned up a lot of conflicting information about determining what the temperature and pressure ranges to expect at various depths.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to be able to build something that can go to 4000 meters or even 6000 meters depth. My interest is chiefly in being able to carry illumination and cameras.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can someone direct me to validated resources of temp pressure and perhaps even pH conditions. Has anyone ever heard of using fused silica cylinders to hold camera/lighting/battery packs for an ocean going ROV?&lt;/p&gt;&#xA;" OwnerUserId="2916" LastEditorUserId="725" LastEditDate="2017-05-12T14:42:07.010" LastActivityDate="2017-05-12T14:42:07.010" Title="What are the temperature and pressure conditions an ROV design would have to deal with to descend to 4000m?" Tags="|ocean|oceanography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4889" PostTypeId="1" CreationDate="2015-05-18T11:03:02.483" Score="8" ViewCount="1124" Body="&lt;p&gt;Well correlation and calibration is an important step in any type of seismic inversion. In order to obtain a good broadband frequency model, the synthetics should be correlated with original seismic data. The wavelet used for generating synthetic can be either statistical or from the data itself. But I'm facing a problem in obtaining a good correlation for those wells which are deviated. Why do deviated wells always show a lower correlation coefficient in well correlation process? &lt;/p&gt;&#xA;" OwnerUserId="2662" LastEditorUserId="28050" LastEditDate="2015-05-18T14:46:25.453" LastActivityDate="2015-07-01T15:32:49.170" Title="Why do deviated wells show poor correlation to seismic data?" Tags="|geophysics|models|waves|inversion|wave-modeling|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4890" PostTypeId="2" ParentId="4884" CreationDate="2015-05-18T12:03:45.190" Score="14" Body="&lt;p&gt;&lt;strong&gt;A cavern filled with natural gas would look like an ordinary cavern. However, natural gas is rarely abundant in caverns.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most natural gas reservoirs occur in the pore spaces of sandstones. These pore spaces are generally up to about 1 mm in diameter. Here's a photomicrograph of a sandstone — the green-blue colour is the pore space; Q, F, L, and M are quartz, feldspar, lithic fragments and mica respectively:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/badnU.jpg&quot; alt=&quot;Helsby sandstone&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The pores of reservoir rocks also contain 'formation' water in various proportions. The relationship between the water and the hydrocarbons can be quite complex, depending on the fluid composition, the reservoir temperature and pressure, and the mineralogy of the rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what about caverns? Trace amounts of methane probably occur in many, if not most, caverns — we're talking here about abundant methane. This is much less common, but it happens. In certain limestones pore spaces can be quite large — up to several metres in diameter. This is called &lt;a href=&quot;http://en.wikipedia.org/wiki/Porosity#Types_of_geologic_porosities&quot; rel=&quot;noreferrer&quot;&gt;vuggy porosity&lt;/a&gt;. If the limestone is charged with natural gas, the vugs will fill with gas, just like the other pores. The space would look like any other limestone cavity. Very large ones are rare, based on a typical &lt;a href=&quot;http://en.wikipedia.org/wiki/Power_law&quot; rel=&quot;noreferrer&quot;&gt;power law&lt;/a&gt; size distribution. There are (copyright and unlicensed) images of such super-pores &lt;a href=&quot;http://www.geoexpro.com/articles/2013/06/heavy-oil-from-an-ancient-reef&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;https://www.spec2000.net/17-speccarb.htm&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;. Recently &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0012821X13002495&quot; rel=&quot;noreferrer&quot;&gt;Mattey et al. (2013; EPSL 374)&lt;/a&gt; wrote about methane in a karst in Gibraltar. I'd estimate that less than 1% of the world's gas is held in vuggy reservoirs. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's another kind of cavern in which you can find natural gas: man-made ones. Natural gas &lt;a href=&quot;http://www.eia.gov/pub/oil_gas/natural_gas/analysis_publications/storagebasics/storagebasics.html&quot; rel=&quot;noreferrer&quot;&gt;is often stored underground&lt;/a&gt;, usually in porous rocks, but sometimes in caverns dissolved out of salt. &lt;a href=&quot;http://www.eia.gov/todayinenergy/detail.cfm?id=3190&quot; rel=&quot;noreferrer&quot;&gt;Around a quarter&lt;/a&gt; of natural gas stock is stored this way in the US. &lt;a href=&quot;https://www.youtube.com/watch?v=ThbkFfXjhxk&quot; rel=&quot;noreferrer&quot;&gt;Here's a video&lt;/a&gt; from such a salt cavern.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Last thing: methane seas can only occur at low temperature. As far as I know, &lt;a href=&quot;http://en.wikipedia.org/wiki/Liquefied_natural_gas&quot; rel=&quot;noreferrer&quot;&gt;liquefied natural gas or LNG&lt;/a&gt; is only stored above ground or on ships in tanks. Lots of natural gas reservoirs have &lt;a href=&quot;http://en.wikipedia.org/wiki/Natural-gas_condensate&quot; rel=&quot;noreferrer&quot;&gt;very light hydrocarbon liquids&lt;/a&gt; in them — but again the liquid would be in tiny pore spaces, not caverns.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-05-18T12:03:45.190" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4891" PostTypeId="2" ParentId="4889" CreationDate="2015-05-18T12:17:25.850" Score="9" Body="&lt;p&gt;&lt;strong&gt;Two-way time to depth calibration is a vertical problem.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How you handle deviated wells probably depends a bit on how you are tying the wells. Here are two things to watch out for:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;You should be tying to true vertical depth (TVD) anyway — make sure you're not using measured depth somehow. I expect you are using TVD — so the deviated section will be distorted (squished). It's gong to be difficult to tie, and the modeled waveform won't make much sense.&lt;/li&gt;&#xA;&lt;li&gt;Sometimes software tries to help you by placing wells at the midpoint between the top- and bottom-hole locations. You don't want this — make sure the well is at the top-hole location, or at the midpoint between the top-hole and kick-off point.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Because of these two things, you may want to ignore deviated wells in the tying effort, if that's an option. If it isn't, focus on tying the straight hole.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ultimately, you'll want to build a 3D velocity model, using horizons to interpolate the velocity field, and maybe even using other velocities (like stacking velocities) to 'fill in' where there are few wells. At that point you can position everything properly, deviated or not.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2015-05-18T12:39:29.840" LastActivityDate="2015-05-18T12:39:29.840" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4892" PostTypeId="1" CreationDate="2015-05-18T13:03:38.763" Score="6" ViewCount="478" Body="&lt;p&gt;Can a cosmic impact event break the Earth's surface in such a way so it expose liquid magma over large areas with solid rocks floating in it as &quot;icebergs&quot;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I wonder, will such magma ocean experience tides and storms so that onybody survived on the &quot;icebergs&quot; to be in danger due to their constant move.&lt;/p&gt;&#xA;" OwnerUserId="2819" LastEditorUserId="64" LastEditDate="2015-05-18T15:44:23.990" LastActivityDate="2015-05-19T07:11:27.790" Title="Can a cosmic impact break Earth's crust in large area exposing the magma ocean?" Tags="|hypothetical|meteorite|magmatism|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="4893" PostTypeId="2" ParentId="4888" CreationDate="2015-05-18T17:20:26.190" Score="6" Body="&lt;p&gt;For pressure, you can use something simple like the fact that pressure increases by around 1 atm with each 10 m of water depth. You can also use some very simple &lt;a href=&quot;http://www.calctool.org/CALC/other/games/depth_press&quot; rel=&quot;nofollow noreferrer&quot;&gt;calculators&lt;/a&gt; that assume a constant density (not a bad assumption) and gives you the different unit conversion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For temperature, it varies a fair amount depending on where in the ocean. The average vertical profile for mid-latitudes, looks something like:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/sObHL.jpg&quot; alt=&quot;http://www.windows2universe.org/earth/Water/temp.html&quot;&gt; (&lt;a href=&quot;http://www.windows2universe.org/earth/Water/temp.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Windows to the Universe&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you need more detail temperature information for a specific location, you can look into the &lt;a href=&quot;https://www.nodc.noaa.gov/OC5/indprod.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;World Ocean Atlas&lt;/a&gt;, which provides observed temperature, salinity (and in some cases other parameters like ph) for the entire world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My suggestion is that, if you need any specific information, you might ask the people at the &lt;a href=&quot;http://www.whoi.edu/main/jason/specifications&quot; rel=&quot;nofollow noreferrer&quot;&gt;Woods Hole Oceanographic Institution&lt;/a&gt; (for instance) that deal with this kind of problem on a regular basis.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2015-05-19T15:10:08.293" LastActivityDate="2015-05-19T15:10:08.293" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4894" PostTypeId="2" ParentId="4868" CreationDate="2015-05-19T02:36:28.430" Score="3" Body="&lt;p&gt;I got in touch with the author of the dataset with my remaining concerns, who responded surprisingly quickly. Here is the essence of everything I learned from people I talked to, including kwinkunks, Simon W, and the author of the dataset, and is intended to augment the existing answers.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For both the grid registration and the cell registration, the dataset provides 3 pieces of info:&#xA;Item #1: lat for each blue dot,&#xA;Item #2: lon for each blue dot,&#xA;Item #3: data (elevation/depth) at each blue dot.&#xA;In addition, for both registrations, each blue dot is at the center of a cell area, and the blue dot represents the average elevation/depth of that cell area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The difference between the two registrations is solely a question of where the outer boundaries (demarcated by the red lines) lie.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cell registered version was created because it was more appropriate for creating maps and images. The grid-registered version presents difficulties for plotting near the poles, which &quot;rolls over&quot; to the other side.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As my application is wave modeling and only a subset of the dataset is required, the grid-registered version, being the authoritative and non-flattened version, is the most appropriate for me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am grateful for everyone who helped.&lt;/p&gt;&#xA;" OwnerUserId="2645" LastActivityDate="2015-05-19T02:36:28.430" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4895" PostTypeId="2" ParentId="4892" CreationDate="2015-05-19T07:11:27.790" Score="14" Body="&lt;p&gt;Let me first correct a small misconception. Where you are talking about 'the magma ocean', you are implying that one exists. This is in fact false. There is no 'magma ocean' in the Earth at the moment (and it has been like that for several billions years). The lavas you see erupting in volcanoes are not coming from a magma ocean. They are coming from either the crust or the mantle, both of which are solid. Magma generation is a localised anomaly in what would otherwise be a solid mass.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, the upper mantle has a section called 'the asthenosphere' which is slightly more ductile than the rest. Think about chocolate in a hot day. Still solid - but it can flow given enough pressure. The modern lithospheric plates (of plate tectonics fame) sort of float on the asthenosphere already now, and that's why you have plate movement and earthquakes and everything.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The asthenosphere is quite deep - some 100 to 200 km deep below the surface. If a cosmic impact is going to create a crater 100 km deep in the Earth, no one will be left around to care about whether they will survive on the 'iceberg'-like lithospheric plates. Again - this is irrelevant. The asthenosphere is ductile in timescales of hunderds of years (at least). If you were to pick up a piece of it now, it will just be like any other rock (albeit quite warm).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A magma ocean event probably occurred very early in the Earth's history (which is not going to happen again since Earth is already here), and the moon forming event also likely liquified quite a lot of the Earth. But this is not going to happen since there is no other big enough body that seems like it's going to collide with us at the moment.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-05-19T07:11:27.790" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4896" PostTypeId="1" CreationDate="2015-05-19T22:11:36.333" Score="23" ViewCount="2802" Body="&lt;p&gt;The carbon dioxide phase diagram shows that at high pressure and normal temperature CO&lt;sub&gt;2&lt;/sub&gt; becomes liquid. Since it is heavier than water, I wonder if there are lakes of liquid CO&lt;sub&gt;2&lt;/sub&gt; at the bottom of the Earth's oceans, and if no, why?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/oB0oS.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="2819" LastEditorUserId="111" LastEditDate="2015-05-20T00:44:00.227" LastActivityDate="2016-05-03T07:52:51.437" Title="Are there pockets of liquid carbon dioxide in Earth's oceans?" Tags="|ocean|oceanography|carbon|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="4897" PostTypeId="1" AcceptedAnswerId="4902" CreationDate="2015-05-19T23:28:02.753" Score="7" ViewCount="1824" Body="&lt;p&gt;I have a text file containing 23 seismic horizons from &lt;a href=&quot;http://www.software.slb.com/products/platform/Pages/petrel.aspx&quot;&gt;Petrel&lt;/a&gt;, Schlumberger's seismic earth interpretation and modelling tool, using the 2D IESX format. Here are the first few rows:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;PROFILE Fault to seafloor    TYPE 1  5 By Petrel 2014.2 (64-bit)                2d_ci7m_gf.ifdf  m  ms&#xA;SNAPPING PARAMETERS 5     2 2&#xA;  4.19846879E+05  4.66812161E+06  1 14  2742.85   5460.00  16382.00 4262               2 276-109::normTOv&#xA;  4.19840089E+05  4.66813210E+06  1 14  2756.25   5461.00  16383.00 4263               2 276-109::normTOv&#xA;  4.19833299E+05  4.66814259E+06  1 14  2769.65   5461.00  16384.00 4264               2 276-109::normTOv&#xA;  4.19826509E+05  4.66815308E+06  1 14  2783.05   5461.00  16385.00 4265               2 276-109::normTOv&#xA;  4.19819720E+05  4.66816357E+06  1 14  2733.93   5462.00  16386.00 4266               2 276-109::normTOv&#xA;  4.19812930E+05  4.66817406E+06  1 14  2809.85   5462.00  16387.00 4267               2 276-109::normTOv&#xA;...&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Each horizon starts with two similar header rows. I'm not too worried about those (but it would be nice to know about them too). I'm more interested in the (400,000 or so) data rows. Here's what I surmise so far:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;(float) — &lt;em&gt;x&lt;/em&gt; location&lt;/li&gt;&#xA;&lt;li&gt;(float) — &lt;em&gt;y&lt;/em&gt; location&lt;/li&gt;&#xA;&lt;li&gt;[1-9] (int) — seems to change with each interpreted segment of horizon&lt;/li&gt;&#xA;&lt;li&gt;14 — no idea&lt;/li&gt;&#xA;&lt;li&gt;(float) — two-way time&lt;/li&gt;&#xA;&lt;li&gt;(float) — no idea&lt;/li&gt;&#xA;&lt;li&gt;(float) — no idea&lt;/li&gt;&#xA;&lt;li&gt;(int) — CDP or trace number&lt;/li&gt;&#xA;&lt;li&gt;2 — no idea&lt;/li&gt;&#xA;&lt;li&gt;(str) — line::dataset&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I have look at the application's documentation, to no avail. Does anyone know what the fields are?&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2019-02-18T16:33:45.353" Title="What are the fields in Petrel's IESX seismic horizon file?" Tags="|geophysics|data-formats|informatics|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4899" PostTypeId="2" ParentId="4896" CreationDate="2015-05-20T02:05:09.733" Score="13" Body="&lt;p&gt;Yes, according to &lt;a href=&quot;http://www.pnas.org/content/103/38/14164.full&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper in the Proceedings of the National Academy of Sciences&lt;/a&gt;. But they also say that this &quot;lake&quot; of liquid CO&lt;sub&gt;2&lt;/sub&gt; is covered by &lt;a href=&quot;http://en.wikipedia.org/wiki/Carbon_dioxide_clathrate&quot; rel=&quot;nofollow noreferrer&quot;&gt;CO&lt;sub&gt;2&lt;/sub&gt; clathrate&lt;/a&gt;, so it's not quite your &lt;a href=&quot;http://en.wikipedia.org/wiki/Brine_pool&quot; rel=&quot;nofollow noreferrer&quot;&gt;average brine pool&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Note about clathrates:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following image is from the &lt;a href=&quot;http://en.wikipedia.org/wiki/Carbon_dioxide_clathrate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia article on CO&lt;sub&gt;2&lt;/sub&gt; clathrate&lt;/a&gt;. It is a CO&lt;sub&gt;2&lt;/sub&gt; hydrate P-T phase diagram with experimental data (black squares) from a 1998 paper by Sloan listed in the &lt;a href=&quot;http://en.wikipedia.org/wiki/Carbon_dioxide_clathrate#References&quot; rel=&quot;nofollow noreferrer&quot;&gt;references&lt;/a&gt; of the Wikipedia article.&lt;img src=&quot;https://i.stack.imgur.com/LmJQK.jpg&quot; alt=&quot;Sloan 1998 CO&amp;lt;sub&amp;gt;2&amp;lt;/sub&amp;gt; hydrate phase diagram&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note the H&lt;sub&gt;2&lt;/sub&gt;O phase lines drawn in. There is a relatively small habitable area for clathrate somewhere inside about 273-280 K (0-7 ºC) and 10-12 bar (or about 90-110m in ocean depth as calculated &lt;a href=&quot;http://www.calctool.org/CALC/other/games/depth_press&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;). Above the phase boundary, the clathrate will dissolve to liquid. Below, to gas. What this diagram does not say (according to a knowledgeable colleague) is that clathrate will not readily form or remain in its semi-organized state given very slight amounts of mechanical agitation. Hence why it does not exist en masse under typical seafloor conditions. &lt;/p&gt;&#xA;" OwnerUserId="2749" LastEditorUserId="2749" LastEditDate="2016-05-02T15:14:16.810" LastActivityDate="2016-05-02T15:14:16.810" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="4900" PostTypeId="2" ParentId="4887" CreationDate="2015-05-20T09:45:54.023" Score="3" Body="&lt;p&gt;It is helpful to start with the USGS definition of &lt;a href=&quot;http://earthquake.usgs.gov/learn/glossary/?term=magnitude&quot; rel=&quot;nofollow&quot;&gt;magnitude&lt;/a&gt;, which can be seen as:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;based on measurement of the maximum motion recorded by a seismograph.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;According to the Seismology Research Centre page &lt;a href=&quot;http://www.src.com.au/earthquake-size/&quot; rel=&quot;nofollow&quot;&gt;Earthquake Size&lt;/a&gt; and the USGS FAQ page &lt;a href=&quot;http://www.usgs.gov/faq/node/3359&quot; rel=&quot;nofollow&quot;&gt;What was the duration of the earthquake? Why don't you report the duration of each earthquake? How does the duration affect the magnitude?&lt;/a&gt;, the duration and magnitude are generally related, specifically given that an earthquake is the movement (motion) of an area of a fault, rather than a single point -&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;So the larger the area of the fault that ruptures, the longer the duration of the earthquake. And larger magnitude earthquakes have larger fault areas.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In the case of the recent Nepalese earthquake, if the fault movement area was larger, then this &lt;em&gt;potentially&lt;/em&gt; could have resulted in a larger magnitude, longer duration earthquake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, a major reason for the uncertainty (why the USGS page refers to the relationship as a 'general' relationship) is due to the geology of the affected area, from the USGS:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The duration of shaking at a point on the ground depends on how long the earthquake took to occur and how the waves move through the ground to that point. If there are a lot of reflections and resonances near the point (for instance in a sedimentary valley) the shaking will last longer. In an area without resonances (for instance on a hard block of rock) it will last a shorter time.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user2872" LastEditorDisplayName="user2872" LastEditDate="2015-05-20T10:53:07.493" LastActivityDate="2015-05-20T10:53:07.493" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4901" PostTypeId="2" ParentId="4897" CreationDate="2015-05-20T12:56:25.440" Score="0" Body="&lt;p&gt;I think fields 6-7 are inline / crossline&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Field 4 is some kind of internal IESX code... don't worry about it&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would've thought there was a seismic amplitude field somewhere... but it has been a long time!&lt;/p&gt;&#xA;" OwnerUserId="2920" LastEditorUserId="28050" LastEditDate="2015-05-20T19:02:04.853" LastActivityDate="2015-05-20T19:02:04.853" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4902" PostTypeId="2" ParentId="4897" CreationDate="2015-05-20T18:34:04.453" Score="6" Body="&lt;ol&gt;&#xA;&lt;li&gt;X-coordinate&lt;/li&gt;&#xA;&lt;li&gt;Y-coordinate    &lt;/li&gt;&#xA;&lt;li&gt;Segment number    &lt;/li&gt;&#xA;&lt;li&gt;Symbol code &lt;/li&gt;&#xA;&lt;li&gt;Two-way time (ms)  &lt;/li&gt;&#xA;&lt;li&gt;Shot-point number &lt;/li&gt;&#xA;&lt;li&gt;CDP number &lt;/li&gt;&#xA;&lt;li&gt;Trace number&lt;/li&gt;&#xA;&lt;li&gt;Line type (2=2D, I=inline, X=crossline) &lt;/li&gt;&#xA;&lt;li&gt;2D line name or 3D survey name&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The format allows for a column between 8 and 9, for amplitude value — not present in this example.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a formatted layout to specific columns. So there is the potential for fields to butt against each other with no spaces between. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The top 2 lines define the horizon name (after PROFILE) and various picking parameters you shouldn't need. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This answer comes from Tom Cox (geoscientist at Schlumberger).&lt;/p&gt;&#xA;" OwnerUserId="2924" LastEditorUserId="28050" LastEditDate="2015-05-20T19:13:23.417" LastActivityDate="2015-05-20T19:13:23.417" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4904" PostTypeId="2" ParentId="4887" CreationDate="2015-05-21T12:39:39.343" Score="2" Body="&lt;p&gt;The energy of an earthquake can be calculated from the &lt;a href=&quot;http://en.wikipedia.org/wiki/Moment_magnitude_scale&quot; rel=&quot;nofollow&quot;&gt;moment magnitude scale&lt;/a&gt; value alone. Two earthquakes of different duration, but the same moment magnitude, have the same energy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The destructive effect of an earthquake is described by the intensity, and a scale such as the &lt;a href=&quot;http://en.wikipedia.org/wiki/Mercalli_intensity_scale&quot; rel=&quot;nofollow&quot;&gt;Mercalli Intensity scale&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I believe there were reports that the ground motion during the Nepal earthquake (Susan Hough of USGS on BBC) had a longer period and shorter duration than initially estimated. This would mean a lower ground acceleration and duration of shaking for the magnitude.  Greater destruction might have resulted if the earthquake (with the same magnitude) had had a longer duration or higher ground acceleration.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The local ground motion (period, acceleration and duration) during an earthquake vary with location due to factors such as underlying geology, fault mechanism, and orientation to fault. This is one reason that following an earthquake seismologists construct a map of earthquake intensity. As the USGS scientist said in her interview, working out the details is a research project. &lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorUserId="178" LastEditDate="2015-05-21T13:33:10.003" LastActivityDate="2015-05-21T13:33:10.003" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4905" PostTypeId="1" AcceptedAnswerId="4910" CreationDate="2015-05-21T13:48:03.683" Score="10" ViewCount="2894" Body="&lt;p&gt;I was going through a report on MASW (Multi Station Analysis of Surface Wave) and found this &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;To avoid the aliasing in the space domain, geophone spacing (Δx) needs to be less than half of the minimum wavelength of interest but channels of the seismograph are limited. As a consequence, geophone spread length (L) is constrained in a certain range. However, on the other hand, a sufficient geophone spread is required for mode separation and the investigation depth.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I understand that this may depend a lot on optimization but is there any approach or research which can be used to make this decision considering both small and large offsets might be useful based on what we are trying to determine.&lt;/p&gt;&#xA;" OwnerUserId="594" LastEditorUserId="28050" LastEditDate="2015-05-22T13:01:09.057" LastActivityDate="2015-05-22T13:29:37.937" Title="How does one determine the optimum offset in a seismic survey?" Tags="|geophysics|seismology|waves|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4906" PostTypeId="1" AcceptedAnswerId="4907" CreationDate="2015-05-21T18:32:58.037" Score="18" ViewCount="1315" Body="&lt;p&gt;The &lt;a href=&quot;http://en.wikipedia.org/wiki/Ice-sheet_dynamics&quot;&gt;wikipedia page on Ice-sheet dynamics&lt;/a&gt; claims that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Ice will not flow until it has reached a thickness of 30 meters (98 ft)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And this &lt;a href=&quot;http://www.physicalgeography.net/fundamentals/10ae.html&quot;&gt;geography website&lt;/a&gt; claims that &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;To be called a glacier, a mass of ice must be capable of motion.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Together, these two claims seem to imply that if it's not thicker than 30m, it's not a glacier. Are either of these claims correct, and do they indeed imply my conclusion?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;N.B. The question arises because I've been working with some &lt;a href=&quot;http://dx.doi.org/10.1016/j.gloplacha.2014.09.003&quot;&gt;literature&lt;/a&gt; and &lt;a href=&quot;http://nsidc.org/data/glacier_inventory/index.html&quot;&gt;databases&lt;/a&gt; that refer to things less than 30m thick as glaciers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Update: looking closer at GlaThiDa, I notice that it contains 490 glaciers listed with mean_depth less than 5m. However, all of these are from a single article (Cogley, 2008) and some of them are apparently only centimeters thick. Something must be wrong with this data; I'm looking into it.&lt;/p&gt;&#xA;" OwnerUserId="63" LastEditorUserId="63" LastEditDate="2015-05-21T19:03:49.033" LastActivityDate="2015-05-21T19:03:49.033" Title="Can glaciers be less than 30m thick?" Tags="|glaciology|glacier|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4907" PostTypeId="2" ParentId="4906" CreationDate="2015-05-21T18:46:23.780" Score="13" Body="&lt;p&gt;The straight answer is no. The definition of a glacier requires the body to be of ice and snow, to move and deform under its own weight. If the body is pure ice the pressure needed to make ice deform corresponds to about 30-40 m of ice pressure. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The definition makes any body not consisting of ice and snow not a glacier. As an example, so-called &quot;saltiers&quot; are bodies of rock salt that move like glaciers. You find such features in the southern part of Iran. They would not qualify as glaciers from the first part of the definition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second part says that they must move. In mountainous terrain snow packs and also thin features of ice can move because they slide downhill. Because these are too thin there is no internal definition so the third part of the definition prevents such features from being glaciers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hence what remains are bodies of ice and snow that have sufficient thickness to induce deformation and hence they will be of a  minimum thickness.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a glaciologist, I do not find this definition very academic. With glaciers reducing in size around the globe many glacier will, in time, pass the limit and cease to be glaciers but knowing when this happens requires physical measurements which for practical reasons (and current technology) can only be made on a  very small subset of the about 160 000 glaciers (not counting the ice sheets) on the earth. It is hence of little practical use when trying to figure out when particular glaciers cease to fit the definition.&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2015-05-21T18:46:23.780" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4908" PostTypeId="1" AcceptedAnswerId="4909" CreationDate="2015-05-22T04:00:46.293" Score="6" ViewCount="1211" Body="&lt;p&gt;The Glen flow law for glaciers is a common relationship linking stress to strain. At its simplest,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\Sigma = k\tau^n$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\tau$ is stress, $\Sigma$ is strain, and $n$ is roughly 3.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand that $k$ depends on temperature and material properties of the ice, and that it can vary over two or three orders of magnitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have been searching the literature to find some example values of $k$ (also called $B$ and $A$) but so far I've had a surprisingly hard time. Is there somewhere that has a compilation of $k$ values from various studies?&lt;/p&gt;&#xA;" OwnerUserId="63" LastActivityDate="2015-05-22T09:54:13.297" Title="Typical values of Glen flow law for glaciers?" Tags="|glaciology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4909" PostTypeId="2" ParentId="4908" CreationDate="2015-05-22T09:54:13.297" Score="2" Body="&lt;p&gt;For glaciology related doubts, the first place to look is &lt;strong&gt;The Physics of Glaciers&lt;/strong&gt; by Kurt M. Cuffey, W. S. B. Paterson. Going through the section 3.4.5 &lt;em&gt;Controls on Creep Parameter A&lt;/em&gt;, should give you a good insight on the topic. It also includes example values.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/LdNx0.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As well as recommendations for values of A as a function of temperature.&#xA;&lt;img src=&quot;https://i.stack.imgur.com/IrmJU.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This section is included in the &lt;a href=&quot;https://books.google.no/books?id=Jca2v1u1EKEC&amp;amp;printsec=frontcover&amp;amp;dq=inauthor:%22W.%20S.%20B.%20Paterson%22&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ei=PvleVdPbHKKuygOHm4CoCg&amp;amp;ved=0CCYQ6AEwAA#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;preview&lt;/a&gt; of the book on Google books.&lt;/p&gt;&#xA;" OwnerUserId="206" LastActivityDate="2015-05-22T09:54:13.297" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4910" PostTypeId="2" ParentId="4905" CreationDate="2015-05-22T12:59:41.327" Score="5" Body="&lt;p&gt;&lt;strong&gt;It depends.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Caveat: my experience is with reflection seismic surveys, but I think many of the principles are similar to MASW.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you guessed: it's an optimization problem. There are lots of factors at play. It's up to the geophysicist to balance the various needs of the survey:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;You need to image the target with useful accuracy (small natural bin size).&lt;/li&gt;&#xA;&lt;li&gt;You want useful signal:noise levels (high fold and trace density).&lt;/li&gt;&#xA;&lt;li&gt;You want near offsets for good estimates of P-wave reflectivity.&lt;/li&gt;&#xA;&lt;li&gt;You want far offsets for good estimates of elastic properties (e.g. density).&lt;/li&gt;&#xA;&lt;li&gt;You may need far offsets to image certain types of geology.&lt;/li&gt;&#xA;&lt;li&gt;You want the acquisition crew to have enough receivers for the design.&lt;/li&gt;&#xA;&lt;li&gt;You want to be able to afford the acquisition and processing!&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;A while ago, I wrote a blog post on the subject: &lt;em&gt;&lt;a href=&quot;http://www.agilegeoscience.com/blog/2012/9/6/fold-for-sale.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fold for sale&lt;/a&gt;&lt;/em&gt;. It's about balancing fold (how many traces go into the stack, basically, a big driver of signal:noise) with cost.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My colleague Evan Bianco and I also did a series on modelling seismic acquisition. If you're into Python at all, there's some code to play with:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;em&gt;&lt;a href=&quot;http://www.agilegeoscience.com/blog/2014/12/11/the-race-for-useful-offsets.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;The race for useful offsets&lt;/a&gt;&lt;/em&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;em&gt;&lt;a href=&quot;http://www.agilegeoscience.com/blog/2014/12/17/laying-out-a-seismic-survey.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Laying out a seismic survey&lt;/a&gt;&lt;/em&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;em&gt;&lt;a href=&quot;http://www.agilegeoscience.com/blog/2015/1/8/it-goes-in-the-bin&quot; rel=&quot;nofollow noreferrer&quot;&gt;It goes in the bin&lt;/a&gt;&lt;/em&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;em&gt;&lt;a href=&quot;http://www.agilegeoscience.com/blog/2015/1/14/seismic-survey-layout-from-theory-to-practice&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seismic survey layout: from theory to practice&lt;/a&gt;&lt;/em&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The greatest minimum offset in a bin is an important consideration, as you guessed. Also notice the spider plots, which try to visualize both maximum offset in a bin, and the range of azimuths going into that bin (which could be important for stress analysis, for example):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/24MS0.png&quot; alt=&quot;Spider plot for a seismic survey&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's hard to go into a lot more detail, other than pointing at more things to read. There are a couple of really good books on this subject:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://books.google.ca/books/about/Planning_Land_3_D_Seismic_Surveys.html?id=ZrqnAKuD44gC&amp;amp;redir_esc=y&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cordsen et al. (2000), &lt;em&gt;Planning Land 3D Seismic Surveys.&lt;/em&gt; SEG Books.&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://books.google.ca/books/about/3D_Seismic_Survey_Design.html?id=tRMiJ94mZE0C&amp;amp;hl=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;Vermeer &amp;amp; Beasley (2012). &lt;em&gt;3D Seismic Survey Design.&lt;/em&gt; SEG Books.&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;For a quick overview, I recommend reading this great paper by Norm Cooper:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Cooper, N (2004). A world of reality—designing land 3D programs for signal, noise, and prestack migration: a 2-part tutorial. &lt;em&gt;The Leading Edge&lt;/em&gt; &lt;strong&gt;23&lt;/strong&gt;, October and December, &lt;a href=&quot;http://dx.doi.org/10.1190/1.1813357&quot; rel=&quot;nofollow noreferrer&quot;&gt;DOI:10.1190/1.1813357&lt;/a&gt; and &lt;a href=&quot;http://dx.doi.org/10.1190/leedff.23.1230_1&quot; rel=&quot;nofollow noreferrer&quot;&gt;DOI:10.1190/leedff.23.1230_1&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2015-05-22T13:29:37.937" LastActivityDate="2015-05-22T13:29:37.937" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4911" PostTypeId="2" ParentId="4881" CreationDate="2015-05-22T13:08:55.873" Score="2" Body="&lt;p&gt;We (myself and three other geophysicists) had a somewhat heated discussion about this a few weeks ago. The best solution we could figure is that the columns were formed simply by contraction Fine cracks formed at the surface of the flow to begin with, and as these cracks formed they provided additional surface for the lavas to cool - so the base of the cracks could cool quicker than the centre of the budding pillar, in turn contracting and propagating downwards. Our best guess for the shape is some heterogeneity in the basalt - the shapes vary from three sides to about eight, so it's not consistent across the whole body. In terms of what &quot;processes&quot; caused the contraction, just the exposure to air/water would provide enough temperature to cause cooling of the fresh basalt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's also worth noting that a large extent of the Antrim flood basalt isn't columnar, so the Causeway (and a few other areas) had just the right amount of cooling.&lt;/p&gt;&#xA;" OwnerUserId="2929" LastActivityDate="2015-05-22T13:08:55.873" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4912" PostTypeId="1" CreationDate="2015-05-25T11:59:29.403" Score="12" ViewCount="1096" Body="&lt;p&gt;Different scientists have brought forth a theory that climate change can cause earthquakes, tsunamis and volcanic eruptions. For example:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Bill_McGuire_%28volcanologist%29&quot;&gt;Professor Bill McGuire&lt;/a&gt; of University College London in his book &lt;em&gt;&lt;a href=&quot;http://www.amazon.co.uk/dp/0199592268/&quot;&gt;Waking the Giant: How a changing climate triggers earthquakes, tsunamis, and volcanoes&lt;/a&gt;&lt;/em&gt; (OUP, 2012).&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://people.rses.anu.edu.au/iaffaldano_g/&quot;&gt;Giampiero Iaffaldano&lt;/a&gt; of the Australian National University, for example in &lt;a href=&quot;http://www.celsias.com/article/there-link-between-climate-change-and-earthquakest/&quot;&gt;this article&lt;/a&gt; or &lt;a href=&quot;http://www.celsias.com/article/there-link-between-climate-change-and-earthquakest/&quot;&gt;this article&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;What is the general view among Earth scientists on this theory? How strong is the evidence that supports or refutes this theory? &lt;/p&gt;&#xA;" OwnerUserId="1109" LastEditorUserId="1109" LastEditDate="2015-05-26T07:06:41.617" LastActivityDate="2016-12-31T06:56:42.953" Title="Can climate change cause earthquakes, tsunamis, or volcanic eruptions?" Tags="|earthquakes|climate-change|tsunami|natural-disasters|volcanic-eruption|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4914" PostTypeId="1" CreationDate="2015-05-26T03:56:45.843" Score="4" ViewCount="195" Body="&lt;p&gt;&lt;a href=&quot;http://www.newscientist.com/article/dn27506-nepal-hit-by-second-huge-earthquake-and-more-are-still-to-come.html#.VWPfvv4vzIU&quot; rel=&quot;nofollow&quot;&gt;Nepal hit by second huge earthquake and more are still to come&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.euronews.com/2015/05/12/nepal-equally-big-earthquakes-coming-in-eastern-regions-expert-tells-euronews/&quot; rel=&quot;nofollow&quot;&gt;Equally big earthquake coming in eastern region of Nepal&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.bbc.com/news/science-environment-32472310&quot; rel=&quot;nofollow&quot;&gt;Nepal quake followed historic pattern&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The experts on mentioned on the first and second link says that the big earthquake is coming on the eastern side of Nepal whereas the expert on third link says the big earthquake is coming on the western and southern Nepal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First of all, I don't understand why experts are predicting a big earthquake in the eastern region once again as the fault there has already ruptured.&#xA;According to the expert mentioned in new scientist,the fault zones can be seen like a 3D zipper. If it is so, the one side of the zipper has opened up(in this case eastern side), then it is western and southern ones that remains to be opened up. (1)So then should not it be affecting western and southern sides?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2)Similarly, if another earthquake does occur, will that earthquake have the same epicenter as that of the previous one? (3)Also will it affect the region where the fault lines running through it have previoulsy been ruptured?&lt;/p&gt;&#xA;" OwnerUserId="2915" LastEditorUserId="2915" LastEditDate="2015-05-26T15:30:24.360" LastActivityDate="2015-05-26T15:30:24.360" Title="Confusion on the Nepal earthquake expert statements" Tags="|earthquakes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4916" PostTypeId="2" ParentId="4914" CreationDate="2015-05-26T14:19:57.437" Score="4" Body="&lt;p&gt;I am confused as well. I asked a question at reddit and a kind guy attempted to answer (it was before the 7.3 &quot;aftershock&quot;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://tectonics.caltech.edu/publications/pdf/Ader_JGR2012.pdf&quot; rel=&quot;nofollow&quot;&gt;This&lt;/a&gt; 2012 study investigated the coupling in the area. You can see that coupling is complete at shallow depths throughout the whole zone. You can also see that coupling tends to decrease at depths towards the eastern termination of the rupture zone of the mainshock, and that coupling was increased in the area of maximum rupture during the mainshock (near Kathmandu). Further towards Bhutan coupling increases but variations are smaller than in subduction zones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.gm.univ-montp2.fr/spip/IMG/pdf/cattingeology14.pdf&quot; rel=&quot;nofollow&quot;&gt;This&lt;/a&gt; paper investigates ancient earthquake scarps in Bhutan and tells us what a truly big earthquake looks like in the Himalayan region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you see the USGS page, aftershock locations are seen to expand outside the rupture area. There are 2 strong aftershocks of particular interest, both around 6.7 magnitude: one at the north-east corner and one at the north-west corner. The fact that they are towards the north is worrying since this is where coupling changes rapidly from nearly 0% to nearly 100%. As Bilham said, during really strong earthquakes even the deeper uncoupled patches slip and add to magnitude. The western aftershock was in an area of minimal slip during the initial earthquake and this surprised me despite the fact that towards the west there were less strong earthquakes in the recent past (so it theory there was room for a strong one), while towards the east there was the 1934 earthquake (which however was not that huge, and additionally in the 80 years since then a couple meters of convergence have taken place, a significant amount of energy).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you see the 1st link (figure 7) the most suspicious area is a narrow zone near the location of the 7.3 &quot;aftershock&quot; (and near the eastern aftershock as well). However the second most suspicious zone is in western Nepal. So, there are arguments for both sides, the one claiming that towards the west there is room for a large earthquake, and the side claiming that towards the east there is a large possibility for a perhaps less severe earthquake. The eastwards rupture (that compressed waves and perhaps stimulated more fault patches than in the opposite direction) and the uneven distribution of aftershocks favored the eastern side from the very beginning.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The history of Himalayan earthquakes reminds us that 10% of strong earthquakes were preceded by foreshocks or were stronger-than-usual aftershocks (like in this case). However, to my knowledge, the stronger foreshock even recorded was 8.1 (or was it 8.6) in the case of the most powerful earthquake ever recorded. A Mw 7.8 being a foreshock of something stronger would be &lt;em&gt;very&lt;/em&gt; unusual, yet from the first day experts were warning for potential giant shocks near Bangladesh. This was in my opinion not correct. Sure the lack of a truly large earthquake in the whole region is unresting, but why now specifically and why there?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately I cannot add more links due to being new here. I hope that, even if not helpful, at least I assured you that you are not the only one in confusion.&lt;/p&gt;&#xA;" OwnerUserId="2938" LastActivityDate="2015-05-26T14:19:57.437" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4917" PostTypeId="2" ParentId="4778" CreationDate="2015-05-26T21:56:15.380" Score="3" Body="&lt;p&gt;It can happen but not like you may guess.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I believe you have seen rupture maps for large earthquakes, such as the 2011 Japan earthquake. In that earthquake, a foreshock of 7.3 took place at the perimeter of the area of largest slip during the main earthquake. This could be interpreted like this (using the asperity model): the foreshock hit at the &quot;slopes&quot; of the asperity but failed to &quot;climb&quot; up immediately; aftershocks were slowly migrating towards the &quot;top&quot; of the asperity, then the main shock happened. Furthermore, once the whole fault was activated, slip at the shallowest parts went beyond charts (40, 50, even 80m of slip were reported locally).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main (deep) asperity had the fewest aftershocks (it slipped completely and without restraints), but there were enough of them in the shallowest parts of the fault. This is probably because the shallower slip was not due to an asperity but rather due to diffused slip of unconsolidated sediments (the &quot;bookshelf&quot; model was used, plus there were aftershocks that appeared to actually... pull back the pieces closer to their original locations). Anyways let's focus on the deeper asperity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An earthquake can take place at the &quot;slopes&quot; of a large asperity but fail to rupture towards the &quot;top&quot; It can however rupture towards the perimeter and achieve respectable sizes. Then another earthquake can take place nearby, but still low at the &quot;slopes&quot;. Finally an earthquake can climb over the top and force even the previously ruptured areas to re-rupture. All 3 earthquakes can very well have epicenters pretty close to one another (such as the two eastern Nepal aftershocks recently). It seems that the 1960 huge Valdivia earthquake demonstrated this behavior but I have yet to find a good, detailed, open-access study on it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Concerning Fred's answer, unfortunately &lt;a href=&quot;http://cires1.colorado.edu/~bilham/2015%20Nepal/Nepal_2015_earthquake.html&quot; rel=&quot;nofollow&quot;&gt;Bilham&lt;/a&gt; (he mentions Jones and Molnar, 1986) (search for &quot;preceded&quot;) says that 10% of strong earthquakes in the history of Himalaya have been preceded by strong shocks. Other sources support Fred's answer, but I would choose to believe Bilham.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Concerning the &quot;lots of aftershocks&quot; notice that the author of the question pointed, for a given earthquake with a normal aftershock sequence it is expected that its strongest aftershock is 1.2 magnitude smaller than the mainshock. For this case, this would yield 6.6. In fact, the strongest ones were the 7.3, an 6.7 and a 6.6, so yes this is anomalous, but the empirical 1.2 value I mentioned is a bit smaller for Himalayas. Still, an 7.3 is anomalously large but &lt;em&gt;before&lt;/em&gt; that time we had no reason to suspect an anomalous aftershock sequence (to my knowledge of course, I searched for b-values but did not find anything during the first days of aftershock activity).&lt;/p&gt;&#xA;" OwnerUserId="2938" LastActivityDate="2015-05-26T21:56:15.380" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4920" PostTypeId="2" ParentId="4772" CreationDate="2015-05-27T19:44:10.280" Score="2" Body="&lt;p&gt;There already exists at least one method that attempts to use electromagnetic precursors to earthquakes; it actually tries to detect electrical currents running up through active faults, explained by the piezoelectric phenomenon. Search for Varotsos if you want, perhaps there are other approaches as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even though the device has a very long &quot;antenna&quot; (ie it tries to avoid noise which usually has shorter wavelengths) it has had some false positives (power lines may produce signals as well, they are long and signals may be of low frequency.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Personally I would never focus on short wavelengths such as TV frequencies. Varotsos correctly focused on low frequencies (there is a practical limit to the size of the &quot;antenna&quot;, I think it is some 50-100 meters long). So in short, &lt;em&gt;no, TV disturbances will never become a valid earthquake precursor&lt;/em&gt;. Too many false positives would ruin it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Keep in mind that in the aforementioned approach, the first signal comes perhaps 4 months before the earthquake and further signals and seismic data are used in order to further narrow the time window, which right now is in the order of days to weeks. However the location and depth are pretty inaccurate (100 km radius or more) while the magnitude may be almost 1 unit lower (the most recent &quot;success&quot; had a magnitude 0.8 lower but it was a doublet). Currently there is an active &quot;prediction&quot; for an earthquake 100 km around Athens, of magnitude near 6. If it is to come true, it should happen until June or early July, but there are dozens of capable faults within the radius so it is practically useless at this point.&lt;/p&gt;&#xA;" OwnerUserId="2938" LastActivityDate="2015-05-27T19:44:10.280" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4921" PostTypeId="1" CreationDate="2015-05-28T11:45:32.527" Score="10" ViewCount="642" Body="&lt;p&gt;Could anyone recommend a free and reliable software capable of Stochastic seismic inversion for my project? am aware that Petrel is capable of Genetic inversion based on a non-linear multi-trace approach but i have no clue what that is about, I prefer stochastic method because it is more reliable. Any help?&lt;/p&gt;&#xA;" OwnerUserId="2950" LastEditorUserId="595" LastEditDate="2016-07-25T12:19:48.450" LastActivityDate="2016-07-25T12:19:48.450" Title="Stochastic seismic inversion" Tags="|geophysics|inversion|seismic|software|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4922" PostTypeId="1" AcceptedAnswerId="4923" CreationDate="2015-05-28T12:11:58.660" Score="6" ViewCount="445" Body="&lt;p&gt;I would like to create a computer simulation which would fold two plane-ish surfaces into two crumpled-ish surfaces. This in order to simulate the earths crust movement and collisions resulting in mountain chains, vallies and hills etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any existing calculations or models for this? Are these models already put into computer simulations or are they just available on paper?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the math behind this?&lt;/p&gt;&#xA;" OwnerUserId="2948" LastEditorUserId="595" LastEditDate="2016-07-25T11:37:43.383" LastActivityDate="2016-07-25T11:37:43.383" Title="Simulating the earths crust" Tags="|geology|geophysics|geodynamics|simulation|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4923" PostTypeId="2" ParentId="4922" CreationDate="2015-05-28T15:42:10.227" Score="9" Body="&lt;p&gt;I am afraid that you aren't being specific enough to really answer your question: What about mountain chians valleys and hills are you interested in? There are simple and complex models dating back from the 1960s to present. Are you interested in learning about the material properties of the crust, or just topography in general? What about weathering effects? What about the flow laws that govern the lower and middle crust (depending on who you talk to). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would look into the field of dynamic topography and how that is calculated. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Two books that I think might be useful to read are &lt;a href=&quot;http://www.cambridge.org/us/academic/subjects/earth-and-environmental-science/solid-earth-geophysics/solid-earth-introduction-global-geophysics-2nd-edition&quot;&gt;Fowler&lt;/a&gt; and &lt;a href=&quot;http://www.cambridge.org/us/academic/subjects/earth-and-environmental-science/structural-geology-tectonics-and-geodynamics/geodynamics-3rd-edition&quot;&gt;Tourcotte and Schubert&lt;/a&gt;, they will help give you an overview of geodynamics as a field, and what engineering solutions we apply to Earth. In the 1-D and 2-D flow sections there is much about the crust. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good starting paper might be &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/91JB00370/full&quot;&gt;Bird 1991&lt;/a&gt; (sorry, its probably behind a pay wall, but I couldn't find an open pdf on it). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as codes (and consquently mathematics) The two sections of &lt;a href=&quot;http://www.geodynamics.org&quot;&gt;CIG&lt;/a&gt; I would look at are &lt;a href=&quot;https://geodynamics.org/cig/software/#short&quot;&gt;S-T Dynamics&lt;/a&gt; and &lt;a href=&quot;https://geodynamics.org/cig/software/#mc&quot;&gt;Mantle Convection&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am sorry I couldn't provide a comprehensive answer, but I think the sources I've linked may give you a good start and thinking about this problem. &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2015-05-28T15:42:10.227" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4924" PostTypeId="2" ParentId="4922" CreationDate="2015-05-28T15:51:53.370" Score="7" Body="&lt;p&gt;Over longer time scales (hundred thousands to millions of years) deformation of crust can be simulated as a viscous fluid. Basically this amounts to simulating stokes flow (i.e., the math behind the problem). Thin viscous sheet models are also fairly common.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Over shorter time periods (months to thousands of years) viscoelastic models are more appropriate. For even shorter time periods (seconds to days) elastic/poroelastic rheologies are appropriate. That is why ground motion following slip on faults can be simulated simply using elastodynamics.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="725" LastEditDate="2015-05-28T22:44:36.670" LastActivityDate="2015-05-28T22:44:36.670" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4925" PostTypeId="1" CreationDate="2015-05-28T17:53:19.863" Score="4" ViewCount="4183" Body="&lt;p&gt;I know how to find out the first few most common minerals, and I know how to find a list of 6800 minerals that one geologist found as a microscopic grain in this one meteorite. I can't seem to find a good reference for the top few hundred minerals that actually occur in macroscopic quantities in near-surface rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sorting by frequency would be great. A reference including subsurface rocks or other planets would be an interesting bonus.&lt;/p&gt;&#xA;" OwnerUserId="2951" LastActivityDate="2016-12-31T06:54:15.127" Title="What are the most common minerals at the Earth's surface?" Tags="|rocks|minerals|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4926" PostTypeId="2" ParentId="4925" CreationDate="2015-05-28T22:42:55.757" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;I can't seem to find a good reference for the top few hundred minerals that actually occur in macroscopic quantities in near-surface rocks.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That's because such a list does not exist. The 'first few most common minerals' you mentioned, aka the 'rock-forming minerals' account for 99.9% (at least, depends on definition) of the minerals you will find in near-surface environments. It also depends on location - the minerals you will find in a limestone are will be completely different from the minerals in granitic areas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also don't completely seem to understand what you mean by 'macroscopic quantities'. Are you referring to minerals that are large enough to be seem by the naked eye or that are abundant in quantity regardless of their size?&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-05-28T22:42:55.757" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4927" PostTypeId="2" ParentId="4922" CreationDate="2015-05-29T07:36:13.360" Score="3" Body="&lt;p&gt;There are several codes which can probably model what you seem to describe. A few that come to mind (in no particular order) are Underworld, Elefant (C Thieulot) and Elvis (T Gerya). The choice really depends on the exact model you would like to run.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a discussion paper describing Elefant: &lt;a href=&quot;http://www.solid-earth-discuss.net/6/1949/2014/sed-6-1949-2014.html&quot; rel=&quot;nofollow&quot;&gt;http://www.solid-earth-discuss.net/6/1949/2014/sed-6-1949-2014.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2954" LastActivityDate="2015-05-29T07:36:13.360" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4928" PostTypeId="1" CreationDate="2015-05-29T11:45:03.707" Score="7" ViewCount="157" Body="&lt;p&gt;In the process of serpentinisation, protons act as oxidising agents for ferrous ions, which results in the production of dihydrogen gas. How is that possible?&lt;br&gt;&#xA;Dihydrogen being a strong reductor, I woud expect this reaction spontaneously going the opposite way.&lt;/p&gt;&#xA;" OwnerUserId="2956" LastEditorUserId="595" LastEditDate="2015-05-29T13:53:59.453" LastActivityDate="2023-05-29T10:54:37.983" Title="Why is hydrogen formation in serpentinisation an exothermic reaction?" Tags="|geochemistry|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4929" PostTypeId="1" CreationDate="2015-05-29T11:46:28.547" Score="11" ViewCount="1665" Body="&lt;p&gt;The CO&lt;sub&gt;2&lt;/sub&gt; phase diagram shows that at atmospheric pressure and about -78 °C temperature CO&lt;sub&gt;2&lt;/sub&gt; becomes solid:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/zO0fU.gif&quot; alt=&quot;CO2 phase diagram&quot;&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/HPtp0.png&quot; alt=&quot;Another CO2 phase diagram&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wikipedia &lt;a href=&quot;http://en.wikipedia.org/wiki/Carbon_dioxide&quot; rel=&quot;noreferrer&quot;&gt;confirms this&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;At 1 atmosphere (near mean sea level pressure), the gas deposits directly to a solid at temperatures below $−78.5\ \mathrm{^\circ C}$ ($−109.3\ \mathrm{^\circ F}; 194.7 ~\mathrm{K}$) and the solid sublimes directly to a gas above $−78.5\ \mathrm{^\circ C}$. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The lowest temperature measured on Earth is about -90 °C (Vostok station). Does this not mean that CO&lt;sub&gt;2&lt;/sub&gt; should fall as snow at the poles?&lt;/p&gt;&#xA;" OwnerUserId="2819" LastEditorUserId="725" LastEditDate="2016-12-31T06:49:27.437" LastActivityDate="2019-03-22T11:48:44.987" Title="Why are there no CO2 snowfalls on Earth?" Tags="|atmosphere|precipitation|poles|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4930" PostTypeId="2" ParentId="4929" CreationDate="2015-05-29T13:35:59.840" Score="19" Body="&lt;p&gt;There is more to phase change than just what you see on that graph.  At temperatures and pressures that support multiple states (e.g. solid and gas) you have to look at the saturation vapor pressure of the gas and the actual vapor pressure (partial pressure) of the gas -- the line on the graph represents equilibrium between the states.  The differences between the two will tell you if you have net sublimation or net deposition and determine whether you end up with a solid or a gas. For solid CO&lt;sub&gt;2&lt;/sub&gt; to form you need to have more deposition (transition from gas to solid) than sublimation.  The transition to solid may also need help nucleating, though I'm not familiar enough with CO&lt;sub&gt;2&lt;/sub&gt; to say for sure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To summarize, in your example Vostok at -90 C and 1000 hPa you have a rate of CO&lt;sub&gt;2&lt;/sub&gt; molecules depositing and a rate of CO&lt;sub&gt;2&lt;/sub&gt; molecules sublimating.  The partial pressure of CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere is low enough that there is more sublimation than deposition, e.g. net sublimation.  To deposit CO&lt;sub&gt;2&lt;/sub&gt; ice on the ground and have it stay there you would need atmospheric CO&lt;sub&gt;2&lt;/sub&gt; concentrations at least at saturation, which we do not have.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;@Tristan provided some numbers in the comments that atmospheric CO&lt;sub&gt;2&lt;/sub&gt; vapor pressures (partial pressure) are &amp;lt;1 mm Hg (or less than about 133 Pa).  To get net sublimation you need to either reach saturation via increasing the vapor pressure (add more CO&lt;sub&gt;2&lt;/sub&gt;) or reducing saturation vapor pressure (lower the temperature).  He provided an estimate that given CO&lt;sub&gt;2&lt;/sub&gt; partial pressures temperatures approaching -140 C would be needed for net deposition and CO&lt;sub&gt;2&lt;/sub&gt; snow.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="2819" LastEditDate="2019-03-22T11:48:44.987" LastActivityDate="2019-03-22T11:48:44.987" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="4931" PostTypeId="1" CreationDate="2015-05-30T04:22:07.547" Score="11" ViewCount="989" Body="&lt;p&gt;It is generally assumed that clouds affect climate by reflecting sunlight back to space and therefore decreasing the total warming of the Earth.  However, stratospheric ice clouds are said to have a net warming effect, due to (I think) the insulation properties of clouds and the low reflectivity of ice clouds.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How do various clouds affect climate?  Specifically, what is the relative energy balance effect clouds have as you go up in the atmosphere?  Is it just stratospheric ice clouds that have a net warming effect?  What really are the insulation properties of a cloud and how do they compare to the reflectivity? &lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2016-01-28T03:12:12.380" LastActivityDate="2016-04-15T19:57:31.230" Title="How does the influence of clouds on climate vary with height?" Tags="|climate|clouds|ice|stratosphere|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4932" PostTypeId="1" AcceptedAnswerId="4933" CreationDate="2015-05-30T06:24:21.630" Score="6" ViewCount="14416" Body="&lt;p&gt;I have a question about the underground heat at different distances from the core of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was wondering if there was a depth at which you can dig that the decrease in heat (as a result of being lower) and the increase in heat due to the depth that you dug that the loss of heat was the same as the gain in heat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are the assumptions that I am using:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The lower an object is, the cooler the air around it and therefore the cooler the object can become. Cold air tends to sink below heated air. (I'm thinking like a basement is cooler than the top floor during summer without air conditioning).&lt;/li&gt;&#xA;&lt;li&gt;The deeper you dig towards the centre of the earth, the hotter your surroundings become. (While there may be some initial decrease in temperature, I'm assuming as you dig towards the mantle or core the hotter the ground around you is).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I am holding constant the heat from the sun and atmosphere. Is there a defined depth at which the loss of heat (from falling cool air) = gain in heat (from the heat of the earth)? Does the shape of the hole dug affect the depth at which this occurs?&lt;/p&gt;&#xA;" OwnerUserId="2961" LastEditorUserId="2470" LastEditDate="2015-05-30T06:57:41.863" LastActivityDate="2015-05-30T11:35:36.950" Title="Digging depth and heat" Tags="|temperature|geothermal-heat|core|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4933" PostTypeId="2" ParentId="4932" CreationDate="2015-05-30T08:04:11.980" Score="8" Body="&lt;p&gt;The heat equilibrium depth will vary for different locations due to:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Differences in geothermal gradient at different locations (heat emitted by rock). It is generally accepted that the global &lt;a href=&quot;https://en.wikipedia.org/wiki/Geothermal_gradient&quot;&gt;geothermal gradient&lt;/a&gt; is between&#xA;${25 ^o C/km}$ &amp;amp; ${30 ^o C/km}$. At some &lt;a href=&quot;http://www.researchgate.net/publication/248902602_Geothermal_gradients_in_the_Great_Artesian_Basin_Australia&quot;&gt;locations&lt;/a&gt; the gradient can vary between ${15.4 ^o C/km}$ &amp;amp; ${102.6 ^o C/km}$.&lt;/li&gt;&#xA;&lt;li&gt;The temperature of the air will increase with depth due to&#xA;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/mire.201300014/abstract&quot;&gt;auto-compression&lt;/a&gt; of the air (also known as &lt;a href=&quot;http://httphttps://en.wikipedia.org/wiki/Lapse_rate://&quot;&gt;lapse rate&lt;/a&gt;). [&lt;em&gt;Environmental Engineering of South African Mines&lt;/em&gt;, 1989, pp 403-404]. The increase in dry bulb temperature of air due to auto-compression is ${9.66 ^o C/km}$, if there is no change to the humidity of the air.&lt;/li&gt;&#xA;&lt;li&gt;Moisture content of the air. The greater the humidity, the greater&#xA;the heat in the air.&lt;/li&gt;&#xA;&lt;li&gt;Ventilation of the hole being dug and how much heat the moving air is&#xA;removing from the bottom of the hole.&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Temperature of the air entering the hole from the Earth's surface&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The presence or absence of other sources of heat such as machinery, electrical equipment, warm water springs entering the hole and warm bodies.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The age of the hole and its exposure to ventilating air. New holes expose fresh warm rock to air in the atmosphere and the air eventually carries away the heat via ventilation. New holes, or new extensions to holes, are warmer/hotter than old holes.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The shape of the hole will be determined more by its function and geotechnical conditions, such as ground stability, than temperature.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-05-30T08:04:11.980" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4934" PostTypeId="2" ParentId="4932" CreationDate="2015-05-30T11:35:36.950" Score="3" Body="&lt;p&gt;I'd like to add a bit to Fred's answer.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The lower an object is, the cooler the air around it &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not completely accurate. Take for example the atmosphere - the air is hotter near the surface. One of the reasons basements are cooler is that they're not exposed to the heat of sunlight, and it's not only their lower position.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In my opinion, the two most important are 1 and 6 from Fred's answer. To give some perspective to it, assuming a regular gradient of 30 degrees per km, this means that in a depth of only 2 km humans will probably not be able to survive anymore. Remembering that Earth's radius is more than 6000 km, this is but a scratch on the surface.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-05-30T11:35:36.950" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4935" PostTypeId="1" AcceptedAnswerId="4936" CreationDate="2015-05-30T15:55:11.257" Score="13" ViewCount="637" Body="&lt;p&gt;I am considering creating some sort of model of the Earth using real world collected data. Things like worldwide height maps certainly exist, as do many maps of minerals, rainfall, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there worldwide data available on underground cave systems?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By density, I mean the likelihood of there being a cave in a certain place, given coordinates. Hence it does not have to be exact (although this would be better), but a mathematical model or approximation would be useful if the former does not exist.&lt;/p&gt;&#xA;" OwnerUserId="2962" LastEditorUserId="192" LastEditDate="2015-05-30T22:06:45.327" LastActivityDate="2016-12-31T06:51:26.767" Title="Is there a freely usable map of Earth cave systems and/or density?" Tags="|geography|open-data|database|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4936" PostTypeId="2" ParentId="4935" CreationDate="2015-05-30T16:24:34.060" Score="13" Body="&lt;p&gt;You might like to check &lt;a href=&quot;http://www-sop.inria.fr/agos/sis/DB/countries.html&quot; rel=&quot;noreferrer&quot;&gt;World Cave List&lt;/a&gt; which has a pretty extensive list of caves, their depths, and lengths.&lt;/p&gt;&#xA;&lt;p&gt;For example:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This list has been automatically produced from our World Caves Database.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Total depth and length of all caves currently collected in the database:&lt;/em&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Number of caves = 2424&lt;/li&gt;&#xA;&lt;li&gt;Caves deeper than 300m = 1075&lt;/li&gt;&#xA;&lt;li&gt;Caves longer than 3kms = 1628&lt;/li&gt;&#xA;&lt;li&gt;Cumulated depth = 648 932 m&lt;/li&gt;&#xA;&lt;li&gt;Cumulated length = 17 930 192 m&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-12-31T06:51:26.767" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4938" PostTypeId="1" CreationDate="2015-06-01T01:21:52.850" Score="13" ViewCount="1106" Body="&lt;p&gt;I am interested in understanding how to tell if a single day of 'abnormal' weather is due to climate change or not. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From my understanding, you would compare this day's weather to historical weather. However, is a day-to-day comparison accurate? Or would you have to take a large sample, like week, month, or season? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems to me like it would be hard to compare one day to another historical weather average, because the day could just be an outlier not due to climate change...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, how do you tell if a seasonal storm or really hot summer day is due to climate change?&lt;/p&gt;&#xA;" OwnerUserId="2964" LastActivityDate="2015-06-19T13:17:39.373" Title="How to tell if a single day of weather is an anomaly or due to climate change?" Tags="|meteorology|atmosphere|climate|climate-change|" AnswerCount="4" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4939" PostTypeId="2" ParentId="4938" CreationDate="2015-06-01T07:30:35.400" Score="9" Body="&lt;p&gt;The answers to such questions come down to statistical analysis; particularly &lt;a href=&quot;https://en.wikipedia.org/wiki/Statistical_significance&quot;&gt;statistical significance&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Statistical_hypothesis_testing&quot;&gt;statistical hypothesis testing&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When conduction such tests, care must be taken in choosing the data for the analysis: don't compare summer temperatures with winter temperatures. Also, the amount of data used needs to be large enough for the result to be significant. Don't compare the recent apparently anomalous temperature with temperatures for the past 2 or 5 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other thing is seasons don't always start and finish according to human timetables. They vary, sometimes they start early or late so you need to have some leeway when choosing to data to analyze.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Initially you'd get the day of the month of the anomalous data, to account for seasonal variability over the years, you'd then decide how far either side of that date you wanted to compare data: maybe a week or two, possibly three or four.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You would then calculate the required statistical parameters, such a &lt;a href=&quot;https://en.wikipedia.org/wiki/Mean&quot;&gt;mean&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Standard_deviation&quot;&gt;standard deviation&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Standard_error&quot;&gt;standard error&lt;/a&gt; of the data, without the anomalous reading.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You then decide what &lt;a href=&quot;https://en.wikipedia.org/wiki/Confidence_interval&quot;&gt;confidence level&lt;/a&gt; you need for your analysis: 95%, 99.9% or higher. Then you do the hypothesis testing. One such test would be to test the anomalous reading with the mean of the historical data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the result of the hypothesis testing is that the anomalous reading is within the variability of the historical data then it's not due to climate change. If however, the anomalous reading falls outside the range of normal variability for the historical data then you start to look for reason why, of which climate change can be one of many reasons.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-06-01T07:30:35.400" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4940" PostTypeId="1" AcceptedAnswerId="5360" CreationDate="2015-06-01T09:41:57.537" Score="12" ViewCount="43628" Body="&lt;p&gt;Due to a pleasant change in my circumstances, I have been to Lyme Regis several times recently, and it seems as though I'm going to be a regular visitor over the next few years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a former biologist I found the experience of combing the shore of the famous Jurassic coast for fossils to be delightfully addictive. Having spent about six hours over three days doing so, I've amassed a decent collection of ammonite fragments. Having got the bug for doing this, I'm eager to try and find some more impressive specimens.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Chatting to some of the local palaeontologists on the beach it became apparent that to do so you need to split rocks, and that you need to know which rocks to split. It's also clear to me that while I've become attuned to watching for the shapes and patterns indicative of ammonites, I don't yet have the eye for the other colours and shapes of fossil shells and bones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried to do some reading about the geology of the region, but most of what I found online was either too basic (i.e. aimed at non-scientists) or too advanced (i.e. aimed at actual geologists) for me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So: how can I learn to better spot fossils and fossil bearing rocks in this region? I'd be very interested to learn some geology if it would help, but if that's the case, how can I find material pitched to the right level? &lt;/p&gt;&#xA;" OwnerUserId="2968" LastEditorDisplayName="user20559" LastEditDate="2021-06-27T09:24:31.013" LastActivityDate="2022-09-28T23:46:12.913" Title="How can I learn to spot fossils and fossil-bearing rocks on the Jurassic coast?" Tags="|geology|fossils|paleontology|regional-geology|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4942" PostTypeId="2" ParentId="4938" CreationDate="2015-06-01T20:43:36.427" Score="16" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;I am interested in understanding how to tell if a single day of 'abnormal' weather is due to climate change or not.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You can't. The day-to-day, locale-to-locale variations in weather are huge compared to the changes that occur from year-to-year and decade-to-decade, averaged over the surface of the Earth. Most of those climatological variations are periodic in nature (e.g., El Niño Southern Oscillation, North Atlantic Oscillation; note the &quot;oscillation&quot; in the names). Climate change is the small but steady secular change in climate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another way to look at it: Even the most pessimistic of projections is for a 4°C increase over the course of a hundred years. That corresponds to 0.04°C change per year. Weather can bring about a 4°C change over the course of a few minutes. Any one weather event can be attributed to the noisy, flukey nature of weather. Climate change begins to become apparent when one looks at weather events that occur all over the face of the Earth, and over the course of several decades.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-06-01T20:43:36.427" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4944" PostTypeId="2" ParentId="4938" CreationDate="2015-06-02T05:54:24.687" Score="10" Body="&lt;p&gt;The observation of even a few exceptional storms can provide quantitative evidence for climate change. Doing so however requires observing and learning as much as possible about how storms work, and not merely counting storms. With some understanding of how atmospheric systems and storms operate, we have other observational information from physics, chemistry, and planetary science that we can also apply to the question. We should use all the information available.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Bayes%27_rule&quot; rel=&quot;nofollow&quot;&gt;Bayes rule&lt;/a&gt; can help us do this objectively. Here, P(A|B) can be the &lt;em&gt;posterior&lt;/em&gt; probability that the climate has changed (A), given the observation of the exceptional storm (B). P(A) is the &lt;em&gt;prior&lt;/em&gt; probability for climate-change. P(B|A) is the likelihood that storm B occurs given a changed climate (e.g. warmer).  k1 and k2 are constants of proportionality. Let (!A) represent no change of climate. Then we can write two equations for Bayes Rule.      &lt;/p&gt;&#xA;&#xA;&lt;p&gt;P(A|B) = k1 P(A) P(B|A)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;P(!A|B) = k2 P(!A) P(B|!A)     &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The prior odds for a change in climate is P(A):P(!A), and let's assume the prior odds for and against climate change are even, 1:1.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now if we use all the available information we have about atmosphere physics and chemistry, and we observe storm B in detail, we can make an informed estimate of the ratio of likelihoods P(B|A):P(B|!A).  Let's assume that B is an exceptional storm and ten times more likely to occur when the atmosphere is warmer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a storm of type B is observed in actuality, the posterior odds can be applied, and the odds should be updated in favor of climate change to 10:1.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What this means is that the observation of exceptional (extreme) events should inform our opinion on climate change. This approach is most successful however when we have many, and many types, of information on how the atmosphere and climate works. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Measurements taken on a day during extreme weather will of course be outliers, but could also provide important information about how &lt;a href=&quot;http://earthobservatory.nasa.gov/Features/ClimateStorms/page1.php&quot; rel=&quot;nofollow&quot;&gt;In a Warming World, Storms May Be Fewer but Stronger&lt;/a&gt;. We should not assume outliers always represent 'noise' that needs to be averaged away. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It does not seem unreasonable to ask the question whether or not we are seeing effects of climate change in the weather. Thursday morning I read the following on the US National Weather Service forecast discussion page:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;CLIMATE...THERE IS A SMALL CHANCE THAT SEATTLE WILL GET TO 90&#xA;DEGREES ON SUNDAY WHICH WOULD TIE THE RECORD FOR THE DAY. SINCE&#xA;RECORDS STARTED IN SEATTLE AT THE FEDERAL BUILDING DOWNTOWN IN 1891&#xA;THERE HAVE BEEN ONLY SIX DAYS IN THE FIRST WEEK OF JUNE WITH A HIGH&#xA;TEMPERATURE OF 90 DEGREES OR MORE. THE LAST TIME IT HAPPENED WAS&#xA;JUNE 4 2009 WITH A HIGH OF 91 DEGREES. FELTON&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whether or not the temperature exceeds 90 degrees next Sunday, I wouldn't dismiss the question of what mechanisms might be operating out-of-hand. We should try to estimate how much what happens supports (or not) hypotheses based upon physical processes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, use Bayes rule reasoning to estimate the change in posterior odds for a mechanism A that increases the likelihood of P(B|A) and P(!B|!A) by 15%, and decreases the likelihood of P(!B|A) and P(B|!A) by 15%.&#xA;$$\delta = 0.15$$&#xA;Then the likelihood is given by the following, where the record is exceeded for a years and not exceeded for b years.&#xA;$$&#xA;k \times\left[  \frac{P(B \parallel A)}{P(B \parallel !A)}  \right] ^{a}\times   \left[  \frac{P(!B \parallel A)}{P(!B \parallel !A)}  \right] ^{b} &#xA;$$&#xA;$$&#xA;k \times\left[  \frac{1 + \delta}{1 -  \delta}  \right] ^{a-b}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's also look at the support if the record is also exceeded in 2016 and 2017. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Change in posterior odds in favor of A(0.15)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(a) Record Not Exceeded 2015 - Posterior odds decrease from prior odds by 35%. By this method it is possible that additional observations eventually discredit the hypothesis. &#xA;(b) Record Exceeded in 2015 - Posterior odds increase by 35%.&#xA;(c) Record Exceeded in 2015 &amp;amp; 2016 - Posterior odds increase by 83%. &#xA;(d) Record Exceeded in 2015 &amp;amp; 2016 &amp;amp; 2017 - Odds increased by 148%.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, the advantages of using this approach, rather than a frequentist approach, can be more easily understood by considering how it could be applied in practice. For example, how a &lt;a href=&quot;http://www.ecology.com/2014/12/15/ocean-acidification-affecting-shellfish-hatcheries/&quot; rel=&quot;nofollow&quot;&gt;Penn Cove shellfish business&lt;/a&gt; might use these calculated changes of climate-change probability to self-insure their farm. The owner of a shellfish farm may understand that climate change poses a risk to her business, and has hedged for the cost of the odd bad year due to this by putting an extra 100 dollars into an account each month. She has found this has worked well in the past, with the account growing to be large enough to cover costs in bad years, without ballooning too large. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How might she use the information that Seattle is breaking temperature records (and the probability of A may be changing) to adjust this amount? If the temperature record is exceeded in 2015, she may decide to increase the amount to 135 dollars per month, and if the record is exceeded again in 2016 she may decide to increase it to 183 dollars, and if it is exceeded again in 2017 increase it to 248 dollars. The advantage is the Bayes method helps her make a decision to act sooner than by using a frequentist approach. This way she may be able to prepare for future costs. &lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorUserId="178" LastEditDate="2015-06-19T13:17:39.373" LastActivityDate="2015-06-19T13:17:39.373" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4945" PostTypeId="1" CreationDate="2015-06-02T16:10:51.863" Score="6" ViewCount="2732" Body="&lt;p&gt;Mud diapirs are relatively common features in seismic reflection images. What is a mud diapir? How is it different from a mud volcano? What are their common characteristics (size, age, composition)? How are they formed and preserved?&#xA;&lt;img src=&quot;https://i.stack.imgur.com/MyGcW.jpg&quot; alt=&quot;mud diapir&quot;&gt; Source &lt;a href=&quot;http://steveholbrook.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://steveholbrook.com/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2015-06-02T16:24:15.893" LastActivityDate="2015-06-05T07:52:01.857" Title="What is a mud diapir and how does it form?" Tags="|ocean|mud-volcano|sea-floor|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4946" PostTypeId="2" ParentId="4595" CreationDate="2015-06-03T01:58:33.130" Score="6" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Did Jupiter really make Earth (in)habitable?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Perhaps, but it's tough to tell.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;I wrote up &lt;a href=&quot;https://physics.stackexchange.com/questions/160912/the-solar-system-explosion-in-the-nice-model/173692#173692&quot;&gt;an answer&lt;/a&gt; for a question on Physics getting at some more specific issues here; bear with me if I re-use a little bit of it.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How is it physically possible for such a migration to occur?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://en.wikipedia.org/wiki/Planetary_migration&quot; rel=&quot;nofollow noreferrer&quot;&gt;Planetary migration&lt;/a&gt; in the Solar System is described by the &lt;a href=&quot;http://en.wikipedia.org/wiki/Nice_model&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nice Model&lt;/a&gt; (or, actually, the Nice II Model, its successor). Basically, the gas giants started out at different orbital semi-major axes than they are in today. There is one change in order, though: Neptune is closer in than Uranus (making the order Jupiter, Saturn, Neptune, Uranus). Also, there may have been a &lt;a href=&quot;http://en.wikipedia.org/wiki/Hypothetical_fifth_giant_planet&quot; rel=&quot;nofollow noreferrer&quot;&gt;5th giant&lt;/a&gt; (actually an ice giant), which was subsequently ejected. It would have been similar to Uranus and Neptune in composition and size.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a quick summary of the Nice Model:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Planetesimals and Kuiper Belt Objects interact with the giants, moving Jupiter inwards a tad and the other three (or four) outwards.&lt;/li&gt;&#xA;&lt;li&gt;Eventually, &lt;a href=&quot;http://en.wikipedia.org/wiki/Orbital_resonance&quot; rel=&quot;nofollow noreferrer&quot;&gt;resonances&lt;/a&gt; come into play. These are ratios between orbital periods. Jupiter and Saturn cross a mutual threshold.&lt;/li&gt;&#xA;&lt;li&gt;Saturn moves outward and Jupiter moves inward. A chain of events happens, where Neptune and Uranus are dramatically moved outwards, with Neptune being chucked to the rear (and the hypothetical 5th giant being ejected). You can watch the video given in that question &lt;a href=&quot;http://www.youtube.com/watch?v=VXeOh3xmrQM&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Here are the before and after pictures, &lt;strike&gt;stolen&lt;/strike&gt; borrowed from that question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/YH88n.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/6SNpw.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can, specifically, recommend the papers I mentioned there: &lt;a href=&quot;http://www.nature.com/ngeo/journal/v6/n7/full/ngeo1841.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fassett &amp;amp; Minton (2013)&lt;/a&gt;, &lt;a href=&quot;http://arxiv.org/pdf/1405.1880.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Deienno &amp;amp; Nesvorny (2014)&lt;/a&gt;, &lt;a href=&quot;http://www.aanda.org/articles/aa/abs/2009/44/aa12878-09/aa12878-09.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Brasser et al. (2009)&lt;/a&gt;, &lt;a href=&quot;http://arxiv.org/pdf/1109.2949v1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nesvorny (2011)&lt;/a&gt;, &lt;a href=&quot;http://arxiv.org/pdf/1208.2957v1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nesvorny &amp;amp; Morbidelli (2012)&lt;/a&gt;, and &lt;a href=&quot;http://www.nature.com/nature/journal/v435/n7041/abs/nature03539.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gomes, Levison, Tsiganis and Morbidelli (2005)&lt;/a&gt; - in no particular order, I think.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is there a way to verify the migration hypothesis with observations?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Well, simulations were used in some of the mentioned papers, especially in those co-authored by Nesvorny, who was involved in recent developments of the Nice Model. These lead to the hypothetical 5th giant, because in some cases, it is necessary as a sort of sacrificial lamb, to prevent Uranus or Neptune from being flung out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We really can't observe this happening in real time, so simulations are our best shot.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How different would have been the hypothetical planets in the area currently occupied by Earth?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://en.wikipedia.org/wiki/Late_Heavy_Bombardment&quot; rel=&quot;nofollow noreferrer&quot;&gt;Late Heavy Bombardment&lt;/a&gt; might not have happened. That's a whole avenue of investigation into alternative astronomical history. It would involve fewer craters and possibly less fewer small collisions between some objects. It would be a calmer place. No migration = no LHB.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Beyond that, it's hard for anyone to say. Detailed simulations are really difficult, because the &lt;em&gt;exact&lt;/em&gt; conditions that matter - not just orbital positions - are hard to model.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If such a migration toward the Sun started, what prevented Jupiter from continuing inward and collapsing with the Sun?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There just wasn't enough impetus from the encounter with Saturn to fling it inwards. A migration isn't just a planet rushing willy-nilly into space; it's a delicate system of slight orbital changes. All odds were against something like this happening.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is it possible for such a migration to occur again?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Only if the right resonances appear, which is unlikely.&lt;/p&gt;&#xA;" OwnerUserId="1399" LastEditorUserId="-1" LastEditDate="2017-04-13T12:40:15.470" LastActivityDate="2015-06-03T20:55:35.367" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4947" PostTypeId="1" AcceptedAnswerId="4950" CreationDate="2015-06-03T07:00:00.407" Score="6" ViewCount="8173" Body="&lt;p&gt;(.... and if so, of what frequency and amplitude)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This &lt;a href=&quot;https://skeptics.stackexchange.com/questions/27918/does-geopathic-stress-cause-illness&quot;&gt;Skeptics.SE question about nonsense called 'geopathic stress'&lt;/a&gt; made me wonder if and how earth itself emits electromagnetic waves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We need moving charges for that, and I can hardly imagine that things like moving magma or 'moving' radioactive minerals would 'emit' anything, but maybe I'm missing something?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not asking about atmospheric phenomena, or about externally introduced electrical currents (man made, lightning).&lt;/p&gt;&#xA;" OwnerUserId="595" LastActivityDate="2015-06-03T19:40:35.257" Title="Does earth itself emit electromagnetic waves?" Tags="|electromagnetism|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4948" PostTypeId="1" CreationDate="2015-06-03T15:20:06.283" Score="10" ViewCount="10288" Body="&lt;p&gt;Why is it that continental crust is less dense than oceanic, where in fact continental crust is thicker than oceanic crust?&lt;/p&gt;&#xA;" OwnerUserId="2977" LastEditorUserId="725" LastEditDate="2016-02-02T01:23:49.420" LastActivityDate="2016-08-05T00:26:03.567" Title="Why is continental crust less dense than oceanic?" Tags="|geophysics|geology|geochemistry|plate-tectonics|crust|" AnswerCount="5" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4949" PostTypeId="2" ParentId="4948" CreationDate="2015-06-03T15:34:10.110" Score="6" Body="&lt;p&gt;Thickness has nothing to do with density. The density is how much a given volume weighs. If a block of 1m × 1m × 1m weighs 60kg, and another block the same size weighs 100kg, then the second block is more dense than the other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if the material that makes up the continental crust is less dense, then the continental crust will be less dense.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This almost sounds like a homework question, so I will leave references and such for now, but finding densities and compositions of these varying crusts is not too difficult.&lt;/p&gt;&#xA;" OwnerUserId="2514" LastEditorUserId="725" LastEditDate="2016-08-05T00:25:33.723" LastActivityDate="2016-08-05T00:25:33.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4950" PostTypeId="2" ParentId="4947" CreationDate="2015-06-03T19:40:35.257" Score="10" Body="&lt;p&gt;&lt;strong&gt;Yes, the earth emits electromagnetic radiation.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It emits &lt;a href=&quot;http://en.wikipedia.org/wiki/Infrared&quot; rel=&quot;noreferrer&quot;&gt;infrared radiation&lt;/a&gt; with wavelengths of about 1 µm to 1 mm. This is heat, essentially, and much of it radiates into space:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/hMuGb.jpg&quot; alt=&quot;Earth&amp;#39;s energy budget&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most if not all of the earth's rocks are radioactive (e.g. because of minerals containing isotopes in the uranium decay chain, such as potassium-40) and emit &lt;a href=&quot;http://en.wikipedia.org/wiki/Gamma_ray&quot; rel=&quot;noreferrer&quot;&gt;gamma radiation&lt;/a&gt; with wavelengths around $10^{-12}$ m. I'm not sure how much of this radiation would make it through the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You said you're not interested in atmospheric phenomena, but I wonder what the relative contributions of subsurface and atmosphere (e.g. the &lt;a href=&quot;http://en.wikipedia.org/wiki/Auroral_kilometric_radiation&quot; rel=&quot;noreferrer&quot;&gt;auroral kilometric radiation&lt;/a&gt;), as well as manmade sources, would be to the total signature. The planets emit radio waves (ask a radio astronomer), but I suspect most of that energy is from their atmospheres, since Jupiter and Saturn are especially bright. &lt;a href=&quot;https://books.google.ca/books/about/The_Earth_as_a_Distant_Planet.html?id=qLuVCJtRTV0C&amp;amp;hl=en&quot; rel=&quot;noreferrer&quot;&gt;This book&lt;/a&gt; by Vázquez, Pallé and Montañés Rodríguez (2010; Springer) looks like it might address some of this, e.g. in Chapter 4. &lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-06-03T19:40:35.257" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4951" PostTypeId="2" ParentId="4948" CreationDate="2015-06-04T07:55:07.920" Score="2" Body="&lt;p&gt;As mtb-za correclty pointed out, density has nothing to do with thickness. Oceanic crust is made up from basalts coming from mid ocean ridges while continental crusts are made up of all different sorts of materials such as for instance sedimentary rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both continental and oceanic crust &quot;float&quot; on the mantle beneath. Because continental crust is less dense it &quot;floats&quot; higher then oceanic crust. This is called isostacy &lt;a href=&quot;http://en.wikipedia.org/wiki/Isostasy&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/Isostasy&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2954" LastActivityDate="2015-06-04T07:55:07.920" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4952" PostTypeId="2" ParentId="4876" CreationDate="2015-06-04T10:32:20.660" Score="2" Body="&lt;p&gt;Continents are made up of different, lighter materials than oceans and both continents and oceans &quot;float&quot; on the mantle. Continents are also thicker than oceans so erosion does not only need to take care of the ~5 km which is above sea level but it should also erode away the continental root (which can be several 10's of kilometers until the continental crust is actually slightly thinner than oceanic crusts are today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However tectonics is not the only source of topography which can easily be seen if we look at Mars where a hotspot has created an enormous mountain on a tectonically inactive planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if you want to end up with a topography free planet you need to shut down all possible mantle plumes too. &lt;/p&gt;&#xA;" OwnerUserId="2954" LastEditorUserId="725" LastEditDate="2015-06-04T22:31:06.073" LastActivityDate="2015-06-04T22:31:06.073" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4954" PostTypeId="1" AcceptedAnswerId="4955" CreationDate="2015-06-04T15:12:42.577" Score="3" ViewCount="165" Body="&lt;p&gt;The ecological footprint of a human activity can be measured in global hectares (gha). Cotton's ecological footprint to produce one ton of product ranges from 2.17 gha for organic cotton to 3.57 gha for conventional cotton (see &lt;a href=&quot;http://www.sei-international.org/mediamanager/documents/Publications/SEI-Report-EcologicalFootprintAndWaterAnalysisOfCottonHempAndPolyester-2005.pdf&quot; rel=&quot;nofollow&quot;&gt;this analysis&lt;/a&gt;).  How significant is that, relative to our total global ecological footprint?&lt;/p&gt;&#xA;" OwnerUserId="2983" LastEditorUserId="543" LastEditDate="2015-06-06T05:46:17.457" LastActivityDate="2015-06-06T05:48:25.483" Title="How significant is organic cotton agriculture to the USA's total global ecological footprint?" Tags="|climate|ecology|agriculture|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4955" PostTypeId="2" ParentId="4954" CreationDate="2015-06-04T15:37:29.350" Score="4" Body="&lt;p&gt;The ecological footprint is the impact of a person or community on the environment, expressed as the amount of land required to sustain their use of natural resources.  A global hectare (gha) from &lt;a href=&quot;http://en.wikipedia.org/wiki/Global_hectare&quot; rel=&quot;nofollow&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;One global hectare represents the average productivity of all biologically productive areas (measured in hectares) on earth in a given year.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and...&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The global hectare is a useful measure of biocapacity as it can convert things like human dietary requirements into a physical area, which can show how many people a certain region on earth can sustain, assuming current technologies and agricultural methods. It can be used as a way of determining the relative carrying capacity of the earth.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and ...&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The total number of global hectares is approximately 11.3 billion, averaging about 1.8 global hectares per person (2004).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I highly suggest you read this page here:&#xA;&lt;a href=&quot;http://www.footprintnetwork.org/en/index.php/GFN/page/frequently_asked_questions/&quot; rel=&quot;nofollow&quot;&gt;http://www.footprintnetwork.org/en/index.php/GFN/page/frequently_asked_questions/&lt;/a&gt; &#xA;and here:&lt;a href=&quot;http://www.footprintnetwork.org/en/index.php/newsletter/bv/humanity_now_demanding_1.4_earths&quot; rel=&quot;nofollow&quot;&gt;http://www.footprintnetwork.org/en/index.php/newsletter/bv/humanity_now_demanding_1.4_earths&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;which explains global footprint quite nicely and puts it into perspective.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The data show that humanity’s demand on the biosphere for providing natural resources and absorbing carbon dioxide emissions is 44 percent more than what nature can provide. This ecological overshoot means it now takes approximately 18 months for the Earth to regenerate what we use in one year. The urgent threats we are facing today - most notably climate change, but also biodiversity loss, shrinking forests, declining fisheries and freshwater stress - are symptoms of this trend.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2015-06-06T05:48:25.483" LastActivityDate="2015-06-06T05:48:25.483" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4956" PostTypeId="1" AcceptedAnswerId="4957" CreationDate="2015-06-04T16:13:47.147" Score="5" ViewCount="222" Body="&lt;p&gt;So I know scratch tests are pretty common to quickly get an estimate of a rocks hardness. Also tooth enamel is a common material with a 5 on mohs scale. So far so good, but what shocked me is that I heard students on field trips actually use their &lt;em&gt;own&lt;/em&gt; teeth sometimes to determine hardness. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The obvious explanation is that I've been fooled, which I expect will be the answer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But if this is really true, how do your teeth survive? Or is it just an occupational hazard that you're going to need dentures before your thirties as a geologist?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;&lt;sup&gt;Disclaimer: this question comes from a story someone told me some time ago, whose girlfriend studied earth sciences. I found it implausible then, but it keeps bugging me and I can't find information on this except that gold miners probably routinely lost their teeth during the 19th century.&lt;/sup&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="2984" LastActivityDate="2015-06-04T22:18:01.657" Title="Determining hardness using teeth" Tags="|geology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4957" PostTypeId="2" ParentId="4956" CreationDate="2015-06-04T22:18:01.657" Score="6" Body="&lt;p&gt;No, teeth are not used to determine hardness. That would be incredibly stupid. What teeth &lt;em&gt;are&lt;/em&gt; used for is distinguishing silt from clay.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When dealing with very fine grained rocks you might be interested in the relative proportions of clay-sized particles and silt-sized particles in the rock. This is very hard to do, but surprisingly quite easy when you try to put some between your teeth. Clays will have a smooth, paste-like, feeling, whereas silt will feel like fine grained sand. With enough experience you will be able to give a rough estimate of the proportions of the minerals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also notice this related question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/1084/725&quot;&gt;When can taste be used to help identify rocks?&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-06-04T22:18:01.657" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4958" PostTypeId="2" ParentId="4232" CreationDate="2015-06-05T01:47:22.720" Score="7" Body="&lt;p&gt;I just saw this question while looking at Lusi 9th anniversary news. As an author of several studies on this topic, wanted to say that the answer provided by Matt is an excellent summary of the triggering debate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Two updates though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) I published a detailed reexamination and processing of the petrophysical and drilling data from BJP-1. This includes a discussion on the specific errors in the petrophysical model used in the Lupi et al. study and corrigendum. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://interpretation.geoscienceworld.org/content/3/1/SE33.abstract&quot; rel=&quot;nofollow&quot;&gt;http://interpretation.geoscienceworld.org/content/3/1/SE33.abstract&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Max Rudolph et al. have now also published a study in Geophysical Research Letters that undertakes similar modelling to that done in the Lupi et al. study and corrigendum. In this new paper, the effect of Yogyakarta earthquake is modelled using both the Lupi et al. corrigendum velocity model and my fully reprocessed and corrected velocity model. The results of the modelling indicate that the errors in the Lupi et al. velocity model significantly overestimate the effects of the earthquake. Interestingly, these results do also suggest that structure helps amplify the earthquake effects, but that the biggest influence is the increase in seismic wave amplitude that occurs when waves pass upwards from the fast volcanic/volcaniclastic layer into the Kalibeng clays. The domed shape causes little amplification, in contrast to the conclusions of Lupi et al. Regardless, the models all indicate that the effect of the earthquake is still very small, and much less than the known influence of the drilling kick. This new study can be found here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2015GL065310/abstract&quot; rel=&quot;nofollow&quot;&gt;http://onlinelibrary.wiley.com/doi/10.1002/2015GL065310/abstract&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) We have an article in Nature Geoscience published:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/ngeo/journal/v8/n7/full/ngeo2472.html&quot; rel=&quot;nofollow&quot;&gt;http://www.nature.com/ngeo/journal/v8/n7/full/ngeo2472.html&lt;/a&gt;&#xA;&lt;a href=&quot;http://www.nature.com/ngeo/journal/v8/n7/extref/ngeo2472-s1.pdf&quot; rel=&quot;nofollow&quot;&gt;http://www.nature.com/ngeo/journal/v8/n7/extref/ngeo2472-s1.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this study, we use the drilling mud gas measurements from the BJP-1 borehole to directly test the hypothesis that an earthquake triggered liquefaction of the Kalibeng clays at Lusi (which is essential for the earthquake triggering hypothesis). Clay liquefaction is associated with release of gases and fluids. So, we examined the gas measurements coming from the BJP-1 well in the days before and after the Yogyakarta earthquake. Despite the BJP-1 well being open and exposed to almost the entire thickness of the clays, there is no increase in gas release in the 25 hours after the earthquake (the time period between the earthquake and the drilling kick that is alternatively argued to have triggered the disaster). This strongly indicates that the earthquake did not cause any liquefaction of clays at the Lusi location, and is the first actual direct measurements used to test the earthquake triggering hypothesis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition, we examined the source of H2S from Lusi. H2S was observed coming out of the Lusi vent in its first few days of eruption. The earthquake triggering community has argued that this H2S comes from the Kalibeng Clays. In particular, the hypothesis is that the H2S has migrated from great depth into the Kalibeng clays via the Watukosek fault, with these deep hydrothermal fluids ‘priming’ the clays and making them prone to liquefaction. Yet, the gas measurements while drilling BJP-1 reported no H2S in the Kalibeng clays at all. H2S was first observed right at the bottom of the well, a few hours before the Yogyakarta earthquake. H2S was then observed during the drilling kick and then from the Lusi vent. Hence, the drilling gas data indicates that the H2S cannot have been sourced from the Kalibeng clays, and suggests that there is no evidence for deep hydrothermal ‘pre-charging’ of the clays. Rather, the H2S most likely comes from greater depths, near the bottom of the well (which is near or just in Carbonates, in which high H2S levels are commonly observed throughout the basin). This suggests that initial eruptive fluids from Lusi are essentially the same as those during the drilling kick 18 hours earlier, and that these fluids are tapping a deeper source than the Kalibeng clays. The drilling-trigger hypothesis is the only hypothesis that proposes such a deep initial fluid source, and the borehole makes a great pathway for deep fluids in the carbonates to suddenly escape through a 1000m thick sealing volcanic/volcaniclastic layer, pass through the Kalibeng clays and erupt at the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe this does not ‘close the argument’, but it does make the earthquake triggering hypothesis even more unlikely, and pose more questions that this hypothesis seems unable to answer (just like the question as to why the disaster would be triggered by the Yogyakarta quake, when there were many other larger quakes that had no effect). Furthermore, all these new measurements are fully in line with the drilling trigger hypothesis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Like testing any competing hypotheses, you keep throwing data at them until they either fall down or keep standing. The drilling-trigger hypothesis is still standing strong; but the earthquake-trigger hypothesis has either fallen down, or is looking very shaky!&lt;/p&gt;&#xA;" OwnerUserId="2987" LastEditorUserId="2987" LastEditDate="2015-09-11T01:28:40.997" LastActivityDate="2015-09-11T01:28:40.997" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4959" PostTypeId="2" ParentId="4945" CreationDate="2015-06-05T07:52:01.857" Score="5" Body="&lt;p&gt;This is an excellent question, and a topic about which there is a lot of literature. In addition to the volume linked above, I can also recommend:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geological Society of London Special Publication 216: &lt;a href=&quot;http://sp.lyellcollection.org/content/216/1&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://sp.lyellcollection.org/content/216/1&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another good place to start is the extensive body of work done by Chris Morley and Pieter van Rensbergen that examines shale diapirs on seismic as well as in outcrop (good outcrop examples are surprisingly rare). Some good papers, in addition to the above two books, include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Morley, C. K., P. Crevello, and Z. H. Ahmad, 1998, Shale tectonics and deformation associated with active diapirism: the Jerudong Anticline, Brunei Darussalam: Journal of the Geological Society, London, v. 155, p. 475-490.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;van Rensbergen, P., C. K. Morley, D. W. Ang, T. Q. Hoan, and N. T. Lam, 1999, Structural evolution of shale diapirs from reactive rise to mud volcanism: 3D seismic data from the Baram delta, offshore Brunei Darussalam: Journal of the Geological Society, London, v. 156, p. 633-650.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;van Rensbergen, P., and C. K. Morley, 2000, 3D seismic study of a shale expulsion syncline at the base of the Champion delta, offshore Brunei and its implications for the early structural evolution of large delta systems: Marine and Petroleum Geology, v. 17, p. 861-872.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Barber et al., 1986, Mud Volcanoes, Shale Diapirs, Wrench Faults, and Melanges in Accretionary Complexes, Eastern Indonesia, in AAPG Bulletin.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Stewart, S.A. &amp;amp; Davies, R.J. (2006) Structure and emplacement of mud volcano systems in the South Caspian Basin. AAPGBull., 90(5), 771^786.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;If I was to summarise all of the work I have seen over the past 15 years, I'd say that there are three major concepts for shale diapirs:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) That they are large masses of mobilised shale - essentially big masses of shale, akin to salt diapirs. Note this is starting to fall out of favour, but is still relevant in some places, such as the Niger Delta.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Shale diapirs are emplaced in a means more akin to igneous intrusives, undergoing fracturing and stoping of overburden rocks due to their high overpressures. As such, shale diapirs are considered to be more like country rock that has been heavily fractured and invaded by gases and mud. This generates the chaotic seismic character.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) Shale diapirs may be simple artefacts caused by complex structure. Features interpreted on seismic as diapirs have been drilled into in several places, but these well penetrations typically did not encounter indications of mobile or previously mobile shale. This has led to suggestions that many 'diapirs' may just be zones in which the bedding is at high angle, and/or heavily affected by fault processes and gas, leading to zones of poor seismic resolution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My personal view is that there is evidence for all three of the above scenarios, depending on the regional basin and tectonic history.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm sorry this doesn't really answer the question, but I hope it gives you enough threads to research this in more detail.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Good Luck!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mark&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/ItGIk.jpg&quot; alt=&quot;Photo I took of a large shale dyke, Jerudong Anticline, Brunei - also on the front cover of Jan 2009 AAPG Bulletin&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="2987" LastActivityDate="2015-06-05T07:52:01.857" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4960" PostTypeId="2" ParentId="4889" CreationDate="2015-06-05T07:56:08.423" Score="4" Body="&lt;p&gt;One common issue is that sonic logs in deviated wells are affected by rock anisotropy (e.g. TVI in shales), and thus yield quite different velocities than are measured in vertical wells. This may affect your correlations as well as things mentioned above.&lt;/p&gt;&#xA;" OwnerUserId="2987" LastActivityDate="2015-06-05T07:56:08.423" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4961" PostTypeId="2" ParentId="4938" CreationDate="2015-06-05T14:08:35.603" Score="-10" Body="&lt;p&gt;Edited answer...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Individual days weather variations can only be considered anomalies, since the theory of global climate change/global warming/anthropogenic CO2 related greenhouse effect acceleration only is theorized and described as affecting the planet over the course of decades and/or centuries and globally, not individual days or individual locations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With that said&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The weather variations in history have been far greater than any that have occurred during man's brief history of recording the weather, and far greater than any that have occurred during mans use of fossil fuels:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/NZVf2.jpg&quot; alt=&quot;Natural variations in weather, long before the use of fossil fuels, or the recording of temperatures&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Answer:  Weather is weather.  Climate change is a &quot;theory&quot;, not a &quot;premise&quot;.  Therefor with the question depends on the factual existence of climate change, which I believe is incorrect since the foundation knowledge doesn't support the extrapolation of measurement and observation to the extent some people have taken it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please consider that between quantum theory and the standard model, there is a reconciliation that has not been found.  The balance point between that which is miniscule, and that which is massive has NOT been found.  Our knowledge of physics is incomplete.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Example:  Quantum theory vs Standard model (which dictates an origin where the entire universe existed momentarily in a singluarity smaller than a grain of sand that then expanded to create the universe)...  &lt;a href=&quot;http://phys.org/news/2015-02-big-quantum-equation-universe.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;No Big Bang? Quantum equation predicts universe has no beginning&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So where we have observed and believe we understand what we perceive as &quot;matter&quot;, we actually only understand the nature of 5% of what exists.  The remainder, dark matter and dark energy fill the void between electrons and nuclei. Similarly between stars and planets.  This is NASA's web site where the approximate quantification of Dark Matter and Dark Energy is published material:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://science.nasa.gov/astrophysics/focus-areas/what-is-dark-energy/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA Quantification of Dark Energ - Dark Matter&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;By fitting a theoretical model of the composition of the Universe to the combined set of cosmological observations, scientists have come up with the composition that we described above, ~68% dark energy, ~27% dark matter, ~5% normal matter. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Without an understanding of the nature of the balancing act that lies in the middle between tiny and huge, believing we understand energy retention, energy dissipation, and the triggers involved to the point that we can properly determine the way the planetary energy system works is ludicrous.  Physics in it's current state of development does NOT support our belief in CO2 based global warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With the researchers at CERN currently considering and looking for a FIFTH fundamental force, HOW can we believe we know how our planet actually works.&lt;a href=&quot;http://www.bbc.com/news/science-environment-28218775&quot; rel=&quot;nofollow noreferrer&quot;&gt;CERN Looking for FIFTH fundamental Force&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Engineers have spent more than a year upgrading the LHC's systems. The hope is that this will allow a new realm of physics to be opened up!!&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And when it comes to choosing the mathematical model that best fits our observations, we are still waffling between String Theory 11D, String Theory 12D.  And we are attempting to determine if said strings even exist?!?!  &lt;a href=&quot;http://www.math.columbia.edu/~woit/wordpress/?p=343&quot; rel=&quot;nofollow noreferrer&quot;&gt;Discussion of the number of dimensions that exist&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;which posits that there are 10 or 11 dimensions in our universe.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So with our very OBVIOUS failure to understand physics, 95% of it being a dark mystery, and waffling over the number of fundamental forces, whether the origin of the universe was a big bang, how many dimensions there are, etc....HOW is it, we can ask ourselves questions like, is daily weather indicative of climate change, when we should be asking, is it viable to believe we have mastered knowledge of the physics of our existence, to the point necessary to be sure that climate change exists.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We cannot.&lt;/p&gt;&#xA;" OwnerUserId="809" LastEditorUserId="809" LastEditDate="2015-06-07T18:41:45.960" LastActivityDate="2015-06-07T18:41:45.960" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="4962" PostTypeId="1" CreationDate="2015-06-06T05:25:21.680" Score="8" ViewCount="274" Body="&lt;p&gt;I know Pangaea was a supercontinent that existed 270 million years ago and it started to break apart around 200 million years ago. I'm not clear on whether Pangaea was 1,2, or multiple tectonic plates. Can someone help me?&lt;/p&gt;&#xA;" OwnerUserId="2988" LastActivityDate="2015-07-04T03:00:28.103" Title="Explain the Idea of Pangaea and how the continents have reached their current positions" Tags="|tectonics|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4963" PostTypeId="2" ParentId="4962" CreationDate="2015-06-06T08:16:53.810" Score="2" Body="&lt;p&gt;It was almost certainly multiple.    I can't say for 100% but I think it was very very likely - cause of the way they split apart for one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, today: Europe, Asia and in a practical sense, Africa are all connected but contain several different plates.    The Indian Plate and the Eurasian plate are 2 different plates but the land is connected, so you'd never know it was two plates - well, except for the frequent earthquakes.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/DaOfk.png&quot; alt=&quot;Wiki picture of Indian Plate&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source:  &lt;a href=&quot;http://en.wikipedia.org/wiki/Indian_Plate&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://en.wikipedia.org/wiki/Indian_Plate&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plate Tectonics is thought to be about 3.2 billion years old:   &lt;a href=&quot;http://sciencenordic.com/modern-plate-tectonics-arose-32-billion-years-ago&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://sciencenordic.com/modern-plate-tectonics-arose-32-billion-years-ago&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2015-06-06T08:16:53.810" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4964" PostTypeId="1" CreationDate="2015-06-06T16:57:48.193" Score="13" ViewCount="432" Body="&lt;p&gt;Can an earthquake occurring between two plates, like the Pacific Plate and North American Plate cause any effect which would trigger an earthquake in a far away place like the boundary between the Eurasian and Indian Plates, as we know it is a mosaic of plates? &lt;/p&gt;&#xA;" OwnerUserId="2990" LastEditorDisplayName="user2872" LastEditDate="2015-06-07T05:23:04.867" LastActivityDate="2016-08-30T15:40:23.283" Title="Can an earthquake occurring within two plates trigger another earthquake in a far away plate boundary?" Tags="|earthquakes|plate-tectonics|" AnswerCount="4" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4965" PostTypeId="1" AcceptedAnswerId="4966" CreationDate="2015-06-07T04:15:36.353" Score="7" ViewCount="1742" Body="&lt;p&gt;Near the surface, the slope of the moist adiabats are much steeper than dry adiabats due (as I understand it) to the the latent heat released as water vapour condenses. The difference is amplified at greater surface temperatures because warmer air can hold more moisture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why then, are the two lapse rates very similar in the upper atmosphere? My best guess is that condensation stops for some reason, but I'm not sure why this would be the case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/BU3m9.gif&quot; alt=&quot;Skew-T Diagram&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="2991" LastEditorUserId="2991" LastEditDate="2015-06-08T08:35:09.160" LastActivityDate="2015-06-09T18:24:13.663" Title="Why do the dry and moist adiabatic lapse rates converge with height?" Tags="|meteorology|atmosphere|atmospheric-circulation|convection|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4966" PostTypeId="2" ParentId="4965" CreationDate="2015-06-07T21:03:27.080" Score="8" Body="&lt;p&gt;If you look closely at the diagram you'll notice height isn't the primary cause for the convergence between the adiabats, though it is the driver. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that toward the upper right there is still appreciable difference between the adiabats and as you move to the left the height they converge at decreases. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason for this, as your intuition suggests, is that condensation ceases. The reason, simply, is that there is no more water left in the parcel to condense and release latent heat. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recall the lines of constant water vapor mixing ratio (the lines you use to connect surface dewpoint to the LCL). These lines decrease to toward the left and are sloped steeper than the isotherms. As moist parcels ascend the latent heat release is correlated to decreasing water vapor. At some point we exhaust the water vapor and any further ascent cools at the dry adiabatic lapse rate as there is no more condensation. This is what causes the moist and dry adiabats to become parallel at upper levels (higher for warmer / moist surface conditions and lower for cooler / drier source parcels). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the comments, concern was expressed that the skew-t isn't capturing the relevant physics, including how a parcel runs out of water vapor.  The skew-t does indeed capture this information and one way you can observe this is by calculating &lt;a href=&quot;http://en.wikipedia.org/wiki/Equivalent_potential_temperature&quot; rel=&quot;nofollow&quot;&gt;equivalent potential temperature&lt;/a&gt;, $\theta_e$.  This temperature is the temperature of a parcel with all of the water vapor condensed out of it. The more moisture in a parcel, the higher the equivalent temperature will be over its actual temperature.  To calculate it on a Skew-T you raise a parcel high enough for the moist and dry adiabats to be parallel, then descend the parcel.  On the way up once saturation is reached you'll ascend via moist adiabat and once the water vapor is exhausted you descend via a dry adiabat.  You can try this for various source parcels and convince yourself that the Skew-T captures these physics.  You should note that the more moist a surface parcel is, the higher it must ascend and the warmer the equivalent temperature will be.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2015-06-09T18:24:13.663" LastActivityDate="2015-06-09T18:24:13.663" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="4967" PostTypeId="1" AcceptedAnswerId="11926" CreationDate="2015-06-08T06:45:47.453" Score="8" ViewCount="5250" Body="&lt;p&gt;I have, to my knowledge, seen far more lightning strikes and heard more thunderclaps at night than I have during the day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are lightning storms more common at night, or are they just more noticeable at night?  If it is significant, my experience is from the Great Lakes region of the US (Western New York state).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Googling, at least for me, has not been fruitful in answering this question.&lt;/p&gt;&#xA;" OwnerUserId="2996" LastEditorUserId="2996" LastEditDate="2015-06-09T06:23:19.717" LastActivityDate="2017-07-26T21:34:46.393" Title="Are lightning storms more common at night?" Tags="|meteorology|thunderstorm|" AnswerCount="2" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="4968" PostTypeId="2" ParentId="4964" CreationDate="2015-06-08T07:40:13.367" Score="-1" Body="&lt;p&gt;I do not think that is possible. For one earthquake to trigger another earthquake at such large distances plates would need to be extremely rigid. Plates are far to ductile for stresses to be transported over such large distances. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In you specific example it seems even less likely. In your case stress would have to be transmitted over the entire pacific plate and then be transmitted over either the eurasian/pacific plate boundary or the indian/pacific plate boundary to be able to affect the indian/pacific plate boundary.&lt;/p&gt;&#xA;" OwnerUserId="2954" LastActivityDate="2015-06-08T07:40:13.367" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4969" PostTypeId="1" AcceptedAnswerId="5005" CreationDate="2015-06-08T12:45:14.537" Score="3" ViewCount="1751" Body="&lt;p&gt;If we burn all carbon in the Earth's crust, by how much would the atmospheric concentration of CO&lt;sub&gt;2&lt;/sub&gt; increase?&lt;/p&gt;&#xA;" OwnerUserId="2998" LastEditorUserId="725" LastEditDate="2016-09-14T10:45:10.163" LastActivityDate="2016-09-14T10:45:54.957" Title="If we burn all carbon in the Earth's crust, by how much would the atmospheric concentration of $CO_2$ increase?" Tags="|atmosphere|co2|" AnswerCount="2" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="4970" PostTypeId="1" CreationDate="2015-06-09T00:15:16.537" Score="4" ViewCount="1117" Body="&lt;p&gt;I am working on a game, and I have a day/night cycle. Currently I have the sun. Currently every &quot;sun day&quot; is 24 hours, with that being said, how long is every &quot;moon day&quot;? In other words, how much does the moon lag behind the sun. I just need to figure out what the moons speed should be in relativity to the sun. I've done some searches, but wasn't quite sure how to properly word this question.&lt;/p&gt;&#xA;" OwnerUserId="3001" LastActivityDate="2015-06-10T06:17:21.200" Title="How often does the moon &quot;set&quot; for us compared to the sun?" Tags="|moon|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="4972" PostTypeId="2" ParentId="1084" CreationDate="2015-06-09T07:18:34.643" Score="6" Body="&lt;p&gt;I am frequently identifying as an engineering geologist grain size distribution of fine-grained cohesive soil by biting it (for almost 3 decades by now). With some experience one comes close to the actual grain size distribution determined in the lab. This is very useful when immediate decision is neccessary at a construction site.&lt;/p&gt;&#xA;" OwnerUserId="3002" LastActivityDate="2015-06-09T07:18:34.643" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4973" PostTypeId="1" CreationDate="2015-06-09T08:30:58.423" Score="3" ViewCount="949" Body="&lt;p&gt;I have been &lt;a href=&quot;http://www.lab-quip.co.uk/dynamic-cone-penetrometer-dcp&quot; rel=&quot;nofollow&quot;&gt;reading about DCP&lt;/a&gt; and watched &lt;a href=&quot;https://www.youtube.com/watch?v=UadgMNG-LWA&quot; rel=&quot;nofollow&quot;&gt;a video&lt;/a&gt; of how it is done (the video is not in English). But there are something things that are still unclear and I would greatly appreciate some help and clarification. I have these questions:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Is there a standard number of times that the hammer must be dropped?&lt;/li&gt;&#xA;&lt;li&gt;What is recorded after an $x$ number of hammer drops?&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Lat/long coordinates of where test occurred?&lt;/li&gt;&#xA;&lt;li&gt;How far the metal head penetrated the ground (in cm)?&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;What happens to that data? What does it correlate with to give us the strength of the ground? What is that strength measured in?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="3003" LastEditorUserId="28050" LastEditDate="2015-06-09T13:16:13.233" LastActivityDate="2015-06-09T19:15:52.033" Title="Dynamic cone penetrometer (DCP) results and correlation" Tags="|geology|soil|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4974" PostTypeId="1" AcceptedAnswerId="4975" CreationDate="2015-06-09T11:45:57.360" Score="8" ViewCount="155" Body="&lt;p&gt;Ice shelves are present along 75% of Antarctica coast and cover over 1.5 million km2. The two main processes causing mass loss of the ice shelf are basal melting and calving. Which of the two processes is more important in Antarctica?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="2470" LastEditDate="2021-07-06T07:24:49.280" LastActivityDate="2021-07-06T07:24:49.280" Title="What is more important in Antarctica calving or basal melting of the ice shelves?" Tags="|glaciology|ice-sheets|antarctica|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4975" PostTypeId="2" ParentId="4974" CreationDate="2015-06-09T15:35:46.560" Score="6" Body="&lt;p&gt;There are two studies published in 2013 that provide the most recent updates on this balance&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Depoorter, M.A. and 6 others, 2013. Calving fluxes and basal melt rates of Antarctic ice shelves. Nature, 502, 89–92, (03 October 2013),  doi:10.1038/nature12567&lt;/p&gt;&#xA;&lt;p&gt;Rignot, E. and 3 others, 2013. Ice-Shelf Melting Around Antarctica. Science, 341, 6143, 266-270, (19 July 2013), doi: 10.1126/science.1235798&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The first study arrives at a calving loss of 1321 ± 144 Gt/yr year and a total basal mass balance of −1454 ± 174 Gt/yr (− = loss). The mass balance is the net of mass added by freeze on and mass lost by melting so the number does not reflect melting alone. The pure loss by melt is hence larger but from a balance perspective the net is what counts.&lt;/p&gt;&#xA;&lt;p&gt;The second study indicates a calving flux of 1089 ± 139 Gt/yr and a basal melt of 1325 ± 235 Gt/yr. Although they report &amp;quot;melting&amp;quot; it is likely that they mean net balance as in the other study.&lt;/p&gt;&#xA;&lt;p&gt;The two studies have used slightly different approaches to arrive at their results, both indirect, but over all the numbers indicate that basal losses are larger than calving and that the order of magnitude is the same.&lt;/p&gt;&#xA;&lt;p&gt;In more detail, the studies show that calving losses are dominant from the larger ice shelves, the Ross and Filchner-Ronne. Melting dominate regions along the western Antarctic Peninsula and down along the coast of the Bellingshausen and Amundsen seas. For most of the East and West Indian Ocean coastlines losses are relatively small and equal between the two processes.&lt;/p&gt;&#xA;&lt;p&gt;The bottom line is that these studies have changed the perspective from ice loss being predominantly through calving to now slightly dominated by basal melting.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-06-09T15:35:46.560" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4977" PostTypeId="2" ParentId="4973" CreationDate="2015-06-09T19:15:52.033" Score="2" Body="&lt;p&gt;The underlying principle of the DCP is that the rate of penetration of the cone, when driven by a standard force, is inversely related to the strength of the material as measured by, for example, the California Bearing Ratio (CBR) test. Where the pavement layers have different strengths, the boundaries between the layers can be identified and the thickness of the layers determined. A typical result is shown.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is recommended that a reading should be taken at increments of penetration of about 10 mm. However, it is usually easier to take readings after a set number of blows. it is therefore necessary to change the number of blows between readings according to the strength of the layer being penetrated. For good quality granular subbases readings every 5 or 10 blows are normally satisfactory but for weaker sub-base layers and subgrade readings every 1 or 2 blows may be appropriate. Little difficulty is normally experienced with the penetration of most types of granular of weakly stabilised materials. It is more difficult to penetrate strongly stabilised layers, granular materials with large particles and very dense, high quality crushed stone.&#xA;The instrument has been designed for strong materials and therefore the operator should persevere with the test. Penetration rates as low as 0.5 mm/blow are acceptable but if there is no measurable penetration after 20 consecutive blows it can be assumed that the DCP will not penetrate the material. Under these circumstances a hole can be drilled through the layer using either an electric or pneumatic drill or by coring. The lower layers of the pavement can then be tested in the normal way.&lt;/p&gt;&#xA;" OwnerUserId="3005" LastActivityDate="2015-06-09T19:15:52.033" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4978" PostTypeId="2" ParentId="4586" CreationDate="2015-06-10T04:55:38.670" Score="4" Body="&lt;p&gt;I think you should just follow the guidelines provided by the USGS for this calculations (&lt;a href=&quot;http://water.usgs.gov/osw/bulletin17b/dl_flow.pdf&quot; rel=&quot;nofollow&quot;&gt;http://water.usgs.gov/osw/bulletin17b/dl_flow.pdf&lt;/a&gt;). From there you can read: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Flood events can be analyzed using either annual or partial-duration series. The annual flood series is based on the maximum flood peak for each year. A partial-duration series is obtained by taking all flood peaks equal to or greater than a predefined base flood&quot;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They also provide a list of FAQs (&lt;a href=&quot;http://water.usgs.gov/osw/bulletin17b/bulletin_17B.html&quot; rel=&quot;nofollow&quot;&gt;http://water.usgs.gov/osw/bulletin17b/bulletin_17B.html&lt;/a&gt;) and a way to calculate them.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-06-10T04:55:38.670" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4979" PostTypeId="2" ParentId="4970" CreationDate="2015-06-10T06:17:21.200" Score="3" Body="&lt;p&gt;As noted in comments, the earth rotates on its axis in about 23hrs 56 minutes. This is known as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Sidereal_time&quot; rel=&quot;nofollow&quot;&gt;sidereal day&lt;/a&gt;, that is, the day with respect to background stars. (that's not &lt;em&gt;quite&lt;/em&gt; true, but it's good enough unless you're dealing with periods of thousands of years with high accuracy - see the linked wiki article if you care about the detail).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the same time, the Earth is also orbiting around the Sun in the same direction, and the combination of the Earth's spin and its orbit around the Sun gives us the 24-hour solar day that we are familiar with, and that you have already modelled in your game.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now consider how the Moon rises and sets, when seen from a position on Earth. The primary cause of this is, again, the Earth's rotation with it's just-less-than-24-hours period. In addition, this time, one must consider the motion of the Moon around the Earth, which is again in the same direction as the Earth's spin. This results in a period of about 24 hr 50 mins for the apparent motion of the Moon across the sky (&lt;a href=&quot;http://oceanservice.noaa.gov/education/kits/tides/tides05_lunarday.html&quot; rel=&quot;nofollow&quot;&gt;Source&lt;/a&gt;). For your game that may be sufficient info, although if you want to be accurate it is &lt;a href=&quot;https://en.wikipedia.org/wiki/Orbit_of_the_Moon&quot; rel=&quot;nofollow&quot;&gt;complicated&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Remember to also take account of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Lunar_phase&quot; rel=&quot;nofollow&quot;&gt;phases of the moon&lt;/a&gt; - because the whole earth-moon system is also in orbit around the sun, and because the moon is only visible via reflected light, the mere fact that the moon is above the horizon when seen from a given point on earth does not mean that it is visible.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2015-06-10T06:17:21.200" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4980" PostTypeId="1" AcceptedAnswerId="5115" CreationDate="2015-06-10T21:26:31.400" Score="6" ViewCount="162" Body="&lt;p&gt;Paleomagnetism can be measured as the magnetic field at the time of rock forming is preserved in some minerals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could the paleomagnetism and the present magnetic field somehow influence the movements of tectonic plates? &lt;/p&gt;&#xA;" OwnerUserId="3009" LastActivityDate="2020-01-05T18:23:26.887" Title="Could the magnetic field influence tectonic forces" Tags="|plate-tectonics|paleomagnetism|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4982" PostTypeId="1" AcceptedAnswerId="4984" CreationDate="2015-06-11T07:20:59.030" Score="5" ViewCount="3680" Body="&lt;p&gt;Even though the physics of wave breaking for ocean surface waves may not be well understood, what wave breaking is and what it looks like is no mystery to the average beach-goer. However, I am confused to as what &quot;whitecapping&quot; is, in the context of &quot;whitecapping dissipation&quot; of waves that appears in literature.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;What is whitecapping? Is it the white &quot;stuff&quot; that is created when a wave break?&lt;/li&gt;&#xA;&lt;li&gt;If so, what causes the white &quot;stuff&quot;? Is it the same as &quot;foam&quot;, a term that is found in the literature as well?&lt;/li&gt;&#xA;&lt;li&gt;Are the terms &quot;whitecapping&quot; and &quot;wave breaking&quot; synonymously used? Are they in fact one and the same?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Relevant references would also be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorUserId="192" LastEditDate="2015-06-11T15:07:41.240" LastActivityDate="2015-06-11T15:07:41.240" Title="Whitecapping in ocean surface waves" Tags="|ocean|waves|wave-modeling|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4984" PostTypeId="2" ParentId="4982" CreationDate="2015-06-11T15:06:36.920" Score="10" Body="&lt;p&gt;Whitecapping refers to the steepness-induced wave dissipation in deep water during which some air is entrained into the near-surface water, forming an emulsion of water and air bubbles (foam) that appears white. It occurs when the velocity of individual water particles near the wave crest exceed the phase speed of the wave, causing the front face of the wave to become too steep and &quot;break&quot;. Steeper and more vigorous breakers are more efficient at entraining air bubbles into the water column, and they generate more foam.&#xA;Whitecapping is an essential process for air-sea gas exchange.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the wave modeling community, because current spectral wave prediction models do not resolve air entrainment by the breaking waves, we use the term &quot;whitecapping&quot; to describe all steepness-induced deep-water wave dissipation. For example, see &lt;a href=&quot;http://link.springer.com/article/10.1007/BF00232479&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hasselmann (1974)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Waves also break due to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/421/what-causes-waves-to-form-the-characteristic-breaking-shape-as-they-approach-t&quot;&gt;shoaling&lt;/a&gt; as they enter shallow water, and these are usually referred to as plunging breakers. While plunging breakers without doubt generate a lot of foam, we don't use the term whitecapping to describe them. Thus, whitecapping is a specific kind of wave breaking, as described in the first paragraph.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See a comprehensive review by &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0079661107001206&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cavaleri et al. (2007)&lt;/a&gt; for a description of all the processes represented by current wave models. &lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-06-11T15:06:36.920" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4986" PostTypeId="2" ParentId="258" CreationDate="2015-06-12T07:04:25.323" Score="1" Body="&lt;p&gt;At wikipedia you can find some answers. &lt;a href=&quot;http://en.wikipedia.org/wiki/Geothermal_gradient&quot; rel=&quot;nofollow&quot;&gt;http://en.wikipedia.org/wiki/Geothermal_gradient&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here it states that in the crust indeed conduction is the main method of heat trasfer. From the geothermal gradient it is also obvious that the outer core/mantle boundary is a big insulater. Since these two are separate heat transfer from the outer core to the mantle is also mainly by conduction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the mantle it is a story of both convection and conduction. I dont think the final answer is known here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an extra note. It seems that in your question you suggest that heat is generated in the core only. This is not true. Heat is also generated in the mantle through radioactive decay. This is estimated according to the linked wiki to be between 45 and 90% of the heat that escapes earth.&lt;/p&gt;&#xA;" OwnerUserId="2954" LastActivityDate="2015-06-12T07:04:25.323" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4987" PostTypeId="1" AcceptedAnswerId="4988" CreationDate="2015-06-12T14:37:42.197" Score="11" ViewCount="1613" Body="&lt;p&gt;It occurred to me that there might very will be a metric out there that measures and quantifies &quot;daily brightness&quot;. Meaning, how bright any given day is, taking weather conditions and cloud coverage into account.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A general brightness metric is &lt;strong&gt;lumens&lt;/strong&gt;, but I can't find anything on this subject with respect to meteorology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And, if such a metric does exist, what's its range, 0 - 100? What weather/ambient conditions are represented at this range's extrema?&lt;/p&gt;&#xA;" OwnerUserId="3018" LastActivityDate="2017-03-02T08:50:08.597" Title="How can daily brightness be quantified or measured?" Tags="|meteorology|measurements|clouds|light|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4988" PostTypeId="2" ParentId="4987" CreationDate="2015-06-12T15:00:56.797" Score="8" Body="&lt;p&gt;It can be measured in units of energy per surface area, for example, &lt;strong&gt;kWh/m&lt;sup&gt;2&lt;/sup&gt;&lt;/strong&gt;.  The official SI name would be &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiant_exposure&quot; rel=&quot;nofollow noreferrer&quot;&gt;radiant exposure&lt;/a&gt; but I haven't seen that phrase used in a climate or weather context.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, here is a map by NREL of average radiation per &lt;em&gt;day&lt;/em&gt; in the US for July:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/vCvbN.jpg&quot; alt=&quot;NREL map of radiation in the USA&quot;&gt;&#xA;&lt;br /&gt;(Source: &lt;a href=&quot;http://www.nrel.gov/gis/solar.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Renewable Energy Laboratory&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And here is a map for Sweden for the same quantity per &lt;em&gt;year&lt;/em&gt; (hence the much larger numbers):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/fSWaY.png&quot; alt=&quot;SMHI map of radiation in Sweden&quot;&gt;&#xA;&lt;br /&gt;(Source: &lt;a href=&quot;http://www.smhi.se/klimatdata/meteorologi/stralning/normal-globalstralning-under-ett-ar-1.2927&quot; rel=&quot;nofollow noreferrer&quot;&gt;SMHI&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="725" LastEditDate="2017-03-02T08:49:02.977" LastActivityDate="2017-03-02T08:49:02.977" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="4989" PostTypeId="2" ParentId="4987" CreationDate="2015-06-13T01:55:36.763" Score="4" Body="&lt;p&gt;In addition to radiant exposure, for certain locations, some meteorological services record hours of sunlight for periods during each day when the &lt;a href=&quot;http://www.bom.gov.au/climate/austmaps/solar-radiation-glossary.shtml#radiationunits&quot; rel=&quot;nofollow noreferrer&quot;&gt;solar radiance&lt;/a&gt; equals or exceeds ${120\ \rm{W/m^2}}$. The weather observations for Sydney airport, for June 2015 can be seen &lt;a href=&quot;http://www.bom.gov.au/climate/dwo/IDCJDW2125.latest.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. Column 7 lists the sunlight hours for each day listed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of measuring data from the electromagnetic spectrum, ultraviolet radiation levels are measured, but not levels of light visible to the human eye.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Australia, the Bureau of Meteorology measures the hours of sunshine each day but the &lt;a href=&quot;http://www.arpansa.gov.au/uvindex/index.cfm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Australian Radiation Protection and Nuclear Safety Authority&lt;/a&gt; measures and records ultraviolet radiation levels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Real time measurements for 11 locations are posted on this &lt;a href=&quot;http://www.arpansa.gov.au/uvindex/realtime/index.cfm&quot; rel=&quot;nofollow noreferrer&quot;&gt;site&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is snap shot of the data for Alice Springs. The yellow/orange line is the forecast UV and the pale blue line shows the measurements.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/GKw2C.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="725" LastEditDate="2017-03-02T08:50:08.597" LastActivityDate="2017-03-02T08:50:08.597" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4990" PostTypeId="2" ParentId="4964" CreationDate="2015-06-13T23:30:22.667" Score="0" Body="&lt;p&gt;Without further qualification, sure they can. An enormous earthquake on one side of the world will shake the other side of the world, and if there's an incipient earthquake in a fault then that shaking could trigger it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But, if you ask &quot;is it common?&quot;, or &quot;could an earthquake of X magnitude trigger another earthquake Y kilometers away?&quot;, then things get a lot more complex. My recollection is that I have heard of such triggering, but it was presented as a surprise, and certainly not a common occurrence.&lt;/p&gt;&#xA;" OwnerUserId="534" LastActivityDate="2015-06-13T23:30:22.667" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4991" PostTypeId="2" ParentId="2136" CreationDate="2015-06-14T17:08:43.407" Score="2" Body="&lt;p&gt;This statement from Geophysical Data Analysis: Discrete Inverse Theory: William Menke should make things clear for you&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The diagonal elements of the covariance matrix are a measure of the&#xA;  width of the distribution of the data, and the off-diagonal elements&#xA;  indicate the degree to which pairs of data are correlated.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Regarding the second part of your doubt whether a situation is possible where ds = 0 ; this would imply some error in measurement(for example - some noise) and would not have any implication on the geophysical nature of the data . It would be advisable to take multiple readings at different locations in this kind of situation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally ds provides some insight into the quality of data collected but no true information about the &quot;information content of measurement&quot;.&lt;/p&gt;&#xA;" OwnerUserId="594" LastActivityDate="2015-06-14T17:08:43.407" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4993" PostTypeId="1" CreationDate="2015-06-14T20:16:08.293" Score="13" ViewCount="844" Body="&lt;p&gt;Was it the Mediterranean before it dried into small lakes? What was the biggest one before that?&lt;/p&gt;&#xA;" OwnerUserId="3024" LastActivityDate="2015-07-03T17:51:30.040" Title="When was the last time there was a landlocked body of water bigger than the Caspian?" Tags="|earth-history|paleogeography|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="4994" PostTypeId="1" CreationDate="2015-06-15T11:01:58.500" Score="8" ViewCount="550" Body="&lt;p&gt;Regarding the amount of biomass in a tree, what would be the approximate total mass of leaves on a large deciduous tree (e.g. maple, oak) while green in spring? Or, how many leaves could be on such a tree.  This would allow me to multiply by the mass per leaf, which I can measure.&lt;/p&gt;&#xA;" OwnerUserId="3027" LastEditorUserId="543" LastEditDate="2015-11-29T18:47:31.920" LastActivityDate="2015-11-29T18:47:31.920" Title="How do I estimate the mass of a deciduous tree's leaves?" Tags="|forest|ecology|biomass|land-surface-models|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="4995" PostTypeId="1" AcceptedAnswerId="4997" CreationDate="2015-06-15T18:33:17.157" Score="4" ViewCount="152" Body="&lt;p&gt;I'm trying to find the geographical distribution and availability of mineral &lt;a href=&quot;http://www.mindat.org/min-754.html&quot; rel=&quot;nofollow&quot;&gt;Brannerite&lt;/a&gt;. Is there a resource online to know or query where a certain mineral is found?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the link page, they mention certain types of geophysical deposits where this mineral is usually found:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;In granite pegmatites and in granitic gneisses; in silicified pebble conglomerates; in hydrothermal quartz and calcite veins; detrital in placers&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the answer to the former question is negative; Would there be online information about geographical distribution of these geological features?&lt;/p&gt;&#xA;" OwnerUserId="3029" LastEditorUserId="725" LastEditDate="2015-06-16T05:58:32.397" LastActivityDate="2015-06-16T05:58:32.397" Title="Online resources for geographical distribution of minerals" Tags="|geology|mineralogy|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4996" PostTypeId="1" CreationDate="2015-06-15T19:54:05.610" Score="10" ViewCount="1994" Body="&lt;p&gt;Today, Northern Russia is considered quite cold. It is not populated because it has low biological productivity: low light and cold. It can be below -50 at winter and 10 C at summer peak. It is low populated because there is basically nothing to eat. Poor reindeers dig some moss from below the snow, which grows there a little during short summer period. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am telling all of that, because I cannot even imagine what the hell Yakutiya would have been when all north of the continent was 1 km below the ice! Siberia stays permafrost even now, when you have warm summer days +5 Celsius. Certainly, it had to be frozen at glacier time permanently. Meantime, it is curious how people managed to cross the Bering Land Bridge during that latest glacier. How was that possible at that time, was it a Polar Voyage? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, I read that Yakutiya was &lt;a href=&quot;http://www.newscientist.com/article/mg21328464.900-siberia-was-a-wildlife-refuge-in-the-last-ice-age.html#.VX8fMc9Viko&quot; rel=&quot;noreferrer&quot;&gt;a wild life refugee during the last ice age&lt;/a&gt;. It had much more rich wild life than now, comparative to what we have in Africa today. People appeared there 12 000 years ago, when half of the Great Glacier was melted&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/XLULa.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and slaughtered mammoth. The mega-fauna extinction collapsed Siberian ecosystem, &lt;a href=&quot;https://en.wikipedia.org/wiki/Pleistocene_Park&quot; rel=&quot;noreferrer&quot;&gt;say scientists who undertake an attempt to recover it&lt;/a&gt;. They tell that mammoth grazed grass. Did they procure it from below the snow, like reindeer do? Ok, &lt;a href=&quot;https://en.wikipedia.org/wiki/Beringia&quot; rel=&quot;noreferrer&quot;&gt;Beringia says that&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;During the ice ages, Beringia, like most of Siberia and all of north&#xA;  and northeast China, was not glaciated because snowfall was very&#xA;  light. It was a grassland steppe, including the land bridge, that&#xA;  stretched for hundreds of kilometres into the continents on either&#xA;  side.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Fine. But, the fact that all ice was concentrated over Europe and Canada does not mean that Beringia surface was not permanently frozen. If there is so cold that whole Europe is under 1 km of Ice, the cold Beringia must be frozen either, despite all ice is over Europe. We can have low temperatures without ice, right? And, if it was terribly cold in Europe, it must be at least that cold in Beringia, right? So, what could poor animals eat there, in the frozen desert?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To summarize, my question is: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How is this nonsense possible that the 'freezer' of our planet was flourishing, whereas the rest of the Planet was starving in frozen state during last glacier period? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS! I was suggested to look at the &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/e/e4/Last_glacial_vegetation_map.png&quot; rel=&quot;noreferrer&quot;&gt;climate zones during Last Glacier&lt;/a&gt;. I have seen it but I cannot believe that northern Canada and Greenland was thriving forest whereas almost whole US was under permanent ice sheet. Similarly, we see that Tundra (current Eastern Siberia state) ruled in permafrozen Beijing whereas Eastern Siberia was enjoing same thriving steppe Forest that Alaska did&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Q39ZY.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is unbelievable and that is what I basically ask to explain. I guess that I have just mismapped the colors. There are too few colors. On the other hand, if anomaly did exist, I want to hear that explicitly, desirably with explanation. Is it really large animals who maintained the warmth at the very north (see &quot;Park&quot; above) before people exterminated them or what?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS2 I have revised the &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/e/e4/Last_glacial_vegetation_map.png&quot; rel=&quot;noreferrer&quot;&gt;climate zones map&lt;/a&gt; and realized that we had Polar Desert in Siberia and Alaska rather than Forest Steppe. This makes more sense. But how did we had the large animals and thriving greenlands there anyway? Polar Desert is incompatible with green land, obviously. Polar Desert at zones map seems also to contradict the Beringia article, attributing Beringia to grassland steppe during Ice Age.&lt;/p&gt;&#xA;" OwnerUserId="1206" LastEditorUserId="11908" LastEditDate="2019-03-13T05:00:24.110" LastActivityDate="2019-03-13T05:00:24.110" Title="Siberia (Beringia) during last glacier period" Tags="|climate|glaciology|ice-age|" AnswerCount="1" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="4997" PostTypeId="2" ParentId="4995" CreationDate="2015-06-16T05:58:10.963" Score="3" Body="&lt;p&gt;You did not mention why you are interested in brannerite, so I am assuming you want it as a collector's specimen and not a microscopic crystal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, there is no definite source. However, there are some possibilities:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Try the Handbook of Mineralogy: &lt;a href=&quot;http://handbookofmineralogy.org&quot; rel=&quot;nofollow&quot;&gt;http://handbookofmineralogy.org&lt;/a&gt; and more specifically the &lt;a href=&quot;http://handbookofmineralogy.org/pdfs/brannerite.pdf&quot; rel=&quot;nofollow&quot;&gt;brannerite&lt;/a&gt; page. You will fine there a more detailed list of localities for that mineral.&lt;/li&gt;&#xA;&lt;li&gt;Another option is to run a &lt;a href=&quot;https://scholar.google.com&quot; rel=&quot;nofollow&quot;&gt;Google Scholar&lt;/a&gt; search for brannerite. You can find scholarly papers dealing with brannerite, and occasionally they also mention where they found the mineral or how they obtained it. Notice that in the specific case of brannerite, there are many articles dealing with brannerite structure. This may not be what you're looking for. There is also the problem of accessibility - unless you have an institutional or personal subscription to these journals, you may not be able to access the full article. However, sometimes this information can be found in the freely available abstract.&lt;/li&gt;&#xA;&lt;li&gt;Go to &lt;a href=&quot;http://www.tandfonline.com/loi/vram20&quot; rel=&quot;nofollow&quot;&gt;Rocks &amp;amp; Minerals&lt;/a&gt; magazine and run a search there for brannerite. They may have some articles dealing with localities.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Regarding your second question about geological features, the features may be mapped if they are big enough. This is probably true for granitic gneisses, may be true for pegmatites and conglomerates and unlikely for veins and placers. This will not help you though. Even though the mineral appears in let's say gneisses, 99.9% of gneisses will not contain this mineral. Of those 0.1% that do contain it, only a fraction will have it big enough so you will be able to see with without a microscope, or any larger than a speck of sand.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finding rare minerals is indeed hard. If however you do indeed come across brannerite, I would like to remind you that it contains quite a lot of radioactive elements so don't make jewelry or good luck charms out of it, and washing your hands after dealing with it is usually a good idea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Good luck!&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-06-16T05:58:10.963" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="4998" PostTypeId="2" ParentId="4940" CreationDate="2015-06-16T11:38:28.450" Score="2" Body="&lt;p&gt;As a very general rule, I'd look for rocks deposited in low energy environment, e.g. shale and some carbonates. Waves often destroys remains of animals in sand, so massive sandstones wouldn't be my first place to look. When you find one fossil, continue to look in the same layer. &lt;/p&gt;&#xA;" OwnerUserId="3009" LastActivityDate="2015-06-16T11:38:28.450" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="4999" PostTypeId="1" AcceptedAnswerId="5000" CreationDate="2015-06-16T23:22:25.903" Score="9" ViewCount="973" Body="&lt;p&gt;I'm currently having a (possibly useless) argument with somebody over the internet who is adamantly claiming that the Earth is flat. I know that this person could just be pulling my leg or trying to get a rise out of me but I'm still taking the challenge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They are using this image in response to almost any argument.&lt;img src=&quot;https://i.stack.imgur.com/mj9wG.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is this document even 'proving' and why is it wrong (or misleading)?&lt;/p&gt;&#xA;" OwnerUserId="3035" LastActivityDate="2016-08-22T04:11:15.200" Title="Why is this &quot;independently reproducible proof of non-curvature&quot; wrong?" Tags="|earth-rotation|earth-observation|" AnswerCount="3" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="5000" PostTypeId="2" ParentId="4999" CreationDate="2015-06-17T02:13:04.633" Score="8" Body="&lt;p&gt;The biggest flaw I see in a cursory look at this work is failure to compensate for &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_refraction&quot; rel=&quot;noreferrer&quot;&gt;atmospheric refraction&lt;/a&gt;.  Density varies in the atmosphere enough that the refractive index varies.  At low angles above the horizon the temperature structure of the atmosphere becomes very important in determining optical refraction and at low angles very close to the ground it becomes extremely important.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When cool air is at the surface and warms with height (e.g. a temperature inversion), which is likely above a cool body of water like a canal (or in winter, or at night and early morning), the resulting density gradient causes light to bend toward the ground.  This means whatever you are observing is actually lower than you perceive it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/omFtq.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;br&gt;&#xA;&lt;sub&gt;&lt;a href=&quot;http://images.tutorvista.com/content/light-refraction/looming.jpeg&quot; rel=&quot;noreferrer&quot;&gt;http://images.tutorvista.com/content/light-refraction/looming.jpeg&lt;/a&gt;&lt;/sub&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the situation where it is warm near the surface and cools aloft you get the opposite and light bends up toward the sky.  This gives rise to the water mirages you can see on hot days on roads or sand (where there is a very strong temperature gradient with height).&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-06-17T02:13:04.633" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5001" PostTypeId="1" CreationDate="2015-06-17T15:30:48.693" Score="13" ViewCount="4741" Body="&lt;p&gt;The &lt;strong&gt;Monin-Obukhov length&lt;/strong&gt; (L) is defined as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$L = - \frac{\rho C_p T_v u^3_*}{kgH}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\rho$=moist air density; $C_p$=air specific heat capacity; $T_v$=virtual temperature; $u^3_*$=wind friction velocity; $k$=0.41 (von Karman constant); $g$=gravity; and $H$=sensible heat. Note that there are lots of different formulations - this one is taken from &lt;a href=&quot;https://www.youtube.com/watch?v=XP6sJSDlDbE&quot;&gt;this video on eddy covariance&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is used when describing how turbulence is affected by bounancy, e.g. from rising thermals from the earth's surface. I would like to get some intuition for what the length actually physically represents. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Monin%E2%80%93Obukhov_length&quot;&gt;wikipedia page&lt;/a&gt; states that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A physical interpretation of L is given by the Monin–Obukhov similarity theory. During the day -L it is the height at which the buoyant production of turbulence kinetic energy (TKE) is equal to that produced by the shearing action of the wind (shear production of TKE).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, that is still pretty opaque to me. To me, that sounds something like a parameter of a distribution that describes at what height wind shear starts to break up up-welling packets of air, but I really don't have any idea. Is there a good intuitive description of this quantity?&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2019-10-12T04:25:48.953" Title="Intuitive definition of the Monin-Obukhov length?" Tags="|wind|convection|air-currents|eddies|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5002" PostTypeId="2" ParentId="5001" CreationDate="2015-06-17T16:07:22.463" Score="8" Body="&lt;p&gt;The way I understand it is the height above the surface at which buoyant (heat) production of turbulence first equals the mechanical (shear) production of turbulence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A more useful definition is given by the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Obukhov_length&quot; rel=&quot;noreferrer&quot;&gt;American Meteorological Society&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A parameter with dimension of length that gives a relation between parameters characterizing dynamic, thermal, and buoyant processes.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;At altitudes below this length scale, shear production of turbulence kinetic energy dominates over buoyant production of turbulence. It is defined by&#xA;  &lt;img src=&quot;https://i.stack.imgur.com/BdRVZ.gif&quot; alt=&quot;equation&quot;&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;where k is von Kármán's constant, u* is the friction velocity (a measure of turbulent surface stress), g is gravitational acceleration, Tv is virtual temperature, and Qv0 is a kinematic virtual temperature flux at the surface. The parameter was first described by Obukhov in 1946, and therefore should not be called the Monin–Obukhov length, even though there is a Monin–Obukhov similarity theory that uses it. The Obukhov length, of order one to tens of meters, is the characteristic height scale of the dynamic sublayer. The Obukhov length is zero for neutral stratification, and positive (negative) for stable (unstable) stratifications. The dimensionless Obukhov length z/ L (where z is height above the surface) is used as a stability parameter, with z/L = 0 for statically neutral stability, and is positive (negative) in a typical range of 1 to 5 (-5 to -1) for stable (unstable) stratification. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2015-06-17T16:20:52.117" LastActivityDate="2015-06-17T16:20:52.117" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5003" PostTypeId="2" ParentId="5001" CreationDate="2015-06-17T18:47:39.417" Score="6" Body="&lt;p&gt;The Obukhov length (&lt;span class=&quot;math-container&quot;&gt;$L$&lt;/span&gt;) measures the&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;relative importance of mechanical shear-generated turbulence and&#xA;density-driven (buoyancy) fluxes (&lt;a href=&quot;https://books.google.com/books?id=rK0nimMqiyAC&amp;amp;pg=PA145&amp;amp;lpg=PA145&amp;amp;dq=relative%20importance%20of%20mechanical%20shear-generated%20turbulence%20and%20%3E%20density-driven%20%28buoyancy%29%20fluxes&amp;amp;source=bl&amp;amp;ots=NWUdcYH8Bb&amp;amp;sig=cqMmLE-EA53yYUSGEbEB2BtbwZY&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ei=yLmBVaW3EIzEogTF44KoAQ&amp;amp;ved=0CCIQ6AEwAA#v=onepage&amp;amp;q=relative%20importance%20of%20mechanical%20shear-generated%20turbulence%20and%20%3E%20density-driven%20%28buoyancy%29%20fluxes&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$L$&lt;/span&gt; can be used to determine the eddy structure of the flow and it provides a measure for the hydrodynamic stability of the boundary layer - it effectively imposes an upper limit on the vertical excursion of fluid particles due to (negative) buoyancy forces.&lt;/p&gt;&#xA;&lt;p&gt;Using the example of a marine layer, if &lt;span class=&quot;math-container&quot;&gt;$Z_l$&lt;/span&gt; is the boundary layer height, the dominant eddy structure (roll vortex motion, free convection or both) can be estimated with the parameter &lt;span class=&quot;math-container&quot;&gt;$-Z_l/L$&lt;/span&gt; (its absolute value measures the stability of the boundary layer). Some common values categorizing the dominant eddy structure and morphology are given in (&lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0493%281989%29117%3C1530%3ATRBRRA%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;). A summary is found in the table below:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/vLLDH.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-06-17T19:16:38.250" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5005" PostTypeId="2" ParentId="4969" CreationDate="2015-06-18T14:40:36.857" Score="6" Body="&lt;p&gt;Short answer: $\rm CO_2$ levels would increase by $209,460$ $\rm ppm$ by using all the available oxygen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Long answer: The mass of carbon in Earth's crust is $9(10)^{22}$ $\rm gC$ (grams of Carbon). The mass of the atmosphere is $5.15(10)^{21}$ $\rm g$. If all the carbon was burned, or otherwise moved to the atmosphere, then the limiting factor would be the $\rm O_2$ (molecular oxygen) available for carbon to bond with to make $\rm CO_2$. Oxygen makes up $209,460$ $\rm ppm$ of the atmosphere. So, assuming the carbon bonded with all available $\rm O_2$ and the remaining carbon did not enter the atmosphere, then there would be an additional $209,460$ $\rm ppm$ of carbon dioxide in the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="684" LastEditorUserId="725" LastEditDate="2016-09-14T10:45:54.957" LastActivityDate="2016-09-14T10:45:54.957" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5007" PostTypeId="1" CreationDate="2015-06-19T12:38:29.667" Score="6" ViewCount="745" Body="&lt;p&gt;I'm confused about the direction of Z (upward or downward?), R (outward or toward the source?) and T.&lt;/p&gt;&#xA;" OwnerUserId="3047" LastActivityDate="2015-11-04T17:55:24.697" Title="How are the ZNE, ZRT and LQT coordinate systems defined?" Tags="|geophysics|seismology|seismic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5008" PostTypeId="1" AcceptedAnswerId="5009" CreationDate="2015-06-19T21:06:28.023" Score="9" ViewCount="5978" Body="&lt;p&gt;For instance, looking at &lt;a href=&quot;http://www.mapsofworld.com/world-maps/wind-and-pressure-jan-enlarge-map1.html&quot;&gt;this map of world air pressure in January&lt;/a&gt; and &lt;a href=&quot;http://www.mapsofworld.com/world-maps/wind-and-pressure-july-enlarge-map.html&quot;&gt;this map of July&lt;/a&gt;, why do some land surfaces have a higher pressure during the winter?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that the tropics and Coriolis forces have something to do with the direction, and that wind flows from higher to lower pressure, but how can you guess what the pressure for an area will be for a certain season?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I describe a certain surface area (water or land, cold or hot, high or low elevation) given a certain season (winter or summer), what generalizations can I make of the average air pressure during that season (high or low)?&lt;/p&gt;&#xA;" OwnerUserId="3049" LastActivityDate="2018-02-27T15:35:07.840" Title="Why do certain areas on Earth have a higher or lower air pressure at sea level?" Tags="|meteorology|temperature|wind|barometric-pressure|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5009" PostTypeId="2" ParentId="5008" CreationDate="2015-06-20T01:48:39.130" Score="9" Body="&lt;p&gt;By way of analogy consider a hot air balloon. The balloon encloses some air. As the air is heated, via massive gas burners, the air in the balloon becomes less dense compared to the air outside the balloon and eventually the less dense air in the balloon rises, lifting the balloon into the air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Atmospheric air in contact with the Earth does the same thing. Air is differentially heated and cooled due to the effects of the Sun, clouds, cold air injected from polar regions and warm or hot air injected from equatorial regions. This affects the energy of the air and its density. Air density is also affected by moisture; very little over dry hot deserts and more over oceans, lakes, large water reservoirs and forests, due to transpiration from trees.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The temperature differentials result in relatively warmer and cooler spots within the air in contact with the Earth's surface and above it. Air in the relatively warmer spots rises. The height to which it rises will in part be affected by the amount of heat it contains when it starts to rise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The surface of the Earth immediately below the column of rising air experiences less air pressure than neighboring regions, hence such regions have low air pressure. As the air rises it cools. Eventually, the air falls back down. The area of the Earth's surface below the falling column of air has a higher pressure relative to its neighboring areas, giving rise to high pressure systems.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The seasonal variation of the general locations of high and low pressure systems are due to the differences in the thermal energy of the air, which in turn is determined by the sources of heat and what might be inhibiting heating.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit: In Reply to Additional Questions in the Comment Section&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you look at the pictures you provided the links for in your question you'll see that during July there is a low pressure zone over North America in addition to the much deeper low pressure zone over north eastern Asia. Additionally, the north-east Asian low pressure zone extends into eastern Europe and north Africa. The high pressure zones, in the northern hemisphere are effectively “islands” over the Atlantic and Pacific Oceans centered around 30 to 40 degrees latitude. Apart from western Europe and parts of the eastern US coast, northern hemisphere landmasses are under low pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you look of the picture for January there is a continuous high pressure zone extending from North American to east Asia and into north Africa. There is even a high pressure zone over Greenland. The regions experiencing low pressure are the most of oceans and the equatorial zones – tropical and sub-tropic part of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;July in the northern hemisphere is the start of the summer and January is well into winter. By July, the landmasses have been accumulating heat from the Sun, since the end of winter, and warming the air above it causing the air to rise and the air pressure to be lower.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Conversely, by January, the landmasses have cooled so they are not heating the air above them. However, air from the northern equatorial region is rising and due to Hadley cells the air falls back down causing the high pressure zones.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="6703" LastEditDate="2016-11-03T15:19:11.150" LastActivityDate="2016-11-03T15:19:11.150" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5010" PostTypeId="1" CreationDate="2015-06-20T13:37:43.860" Score="6" ViewCount="1619" Body="&lt;p&gt;Every continent has a dry strip between about 15º and 35º on its west coast, but they vary drastically in size:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The Baja/Mojave and Atacama are fairly narrow, stretching about 300 miles inland at the widest (using the &quot;25 cm annual precip&quot; definition of desert.&lt;/li&gt;&#xA;&lt;li&gt;The Namib, about 600 miles.&lt;/li&gt;&#xA;&lt;li&gt;The Great Australian Desert covers about 2,000 miles, most of the continent.&lt;/li&gt;&#xA;&lt;li&gt;The Sahara, Arabian Desert, Dasht-e-Lut, and Baluchistan together stretch over 5,500!&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;These are all caused by the winds of the horse latitudes, in turn caused by the continental high-pressure zones, AKA &lt;a href=&quot;https://en.wikipedia.org/wiki/Subtropical_ridge&quot; rel=&quot;noreferrer&quot;&gt;subtropical ridges&lt;/a&gt;.  But why does this produce just a slim strip of desert on some continents but a massive span southwest of Eurasia?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The size of the continent is the obvious answer, but if so why is Australia almost all desert, despite being the smallest continent, surrounded by warm ocean?  Looking at the Andes, the Rocky Mountains, the mountains of Iran, Angola, and Namibia, and the Great Dividing Range, it appears that each subtropical desert tends to end at a mountain range, but not always: the southern Namib climbs half a mile before stretching across half of South Africa, and the Sahara has several highlands.&lt;/p&gt;&#xA;" OwnerDisplayName="user331" LastActivityDate="2018-03-14T23:18:19.977" Title="Why is the Sahara so much larger than the other horse latitude deserts?" Tags="|desert|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5011" PostTypeId="2" ParentId="930" CreationDate="2015-06-20T15:47:53.477" Score="4" Body="&lt;p&gt;You will find the full text of Jim Kossin's migration paper here.&#xA;&lt;a href=&quot;http://www.ssec.wisc.edu/~kossin/articles/nature13278.pdf&quot; rel=&quot;nofollow&quot;&gt;http://www.ssec.wisc.edu/~kossin/articles/nature13278.pdf&lt;/a&gt;&#xA;In it he describes his findings only as an empirical observation.  He does state that the migration is consistent with tropical expansion but he does not attribute the migration to the expansion. In fact he does not get into the subject of attribution at all. Perhaps attrbution will be the subject of a future paper. You may wish to check his list of publications from time to time to see if he has written an attribution paper. His (vey impressive) publication list may be found at &lt;a href=&quot;http://www.ssec.wisc.edu/~kossin/pubs.html&quot; rel=&quot;nofollow&quot;&gt;http://www.ssec.wisc.edu/~kossin/pubs.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2748" LastActivityDate="2015-06-20T15:47:53.477" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5012" PostTypeId="1" AcceptedAnswerId="5049" CreationDate="2015-06-20T17:55:20.043" Score="6" ViewCount="343" Body="&lt;p&gt;With weather radar, it's not uncommon to see large areas of the image blocked out due to detected range folding.  It's my understanding that this occurs when a reflection outside of range comes back after the next pulse has been transmitted, making the receiver think that a late reflection from the first pulse is actually for the second pulse and near by.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/6CoU8.gif&quot; alt=&quot;Range Folding&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Graphic Source:  &lt;a href=&quot;http://www.wdtb.noaa.gov/courses/dloc/topic3/lesson1/Section4/Section4-5.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.wdtb.noaa.gov/courses/dloc/topic3/lesson1/Section4/Section4-5.html&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems to me that it if we could differentiate between pulses, we could eliminate the possibility of range folding error.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Frequency&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;My first thought was that each pulse could be sent at different frequencies.  They would have to be close enough to not affect the amount of energy reflected, but far apart enough to be easily detected and not assumed to be part of doppler shift.  Even something as wide as 1MHz seems to fit this characteristic.  Is there a reason we don't use this method today?&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Polarization&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;If we have to use the same frequency for both pulses, could we instead mount two antennas on the transmitting rig, one polarized clockwise and the other polarized counter-clockwise?  In this configuration, the exact same equipment could be used for transmitting with something that just switches between antennas for each pulse.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm curious if either method would work, and what the possible pitfalls are.&lt;/p&gt;&#xA;" OwnerUserId="3052" LastEditorDisplayName="user1066" LastEditDate="2016-01-11T15:11:20.510" LastActivityDate="2016-01-11T15:11:20.510" Title="Eliminating range folding error in doppler radar returns" Tags="|meteorology|radar|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5013" PostTypeId="1" CreationDate="2015-06-21T00:23:19.017" Score="4" ViewCount="104" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/kWAOO.jpg&quot; alt=&quot;http://bonap.org/Climate%20Maps/hardiness2.png&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I saw this map I was surprised to learn that part of Quebec is in the worst winter hardiness zone of North America (including Greenland). Zone 0a, which is defined as &quot;average winters get colder than 65 below F.&quot; Also, why is it warmer north of Jaques Cartier Strait than the rest of the St. Lawrence? Shouldn't the nearby land (Ile d'Anticosti) make it slightly colder?&lt;/p&gt;&#xA;" OwnerUserId="3024" LastEditorDisplayName="user2872" LastEditDate="2015-08-04T14:55:00.070" LastActivityDate="2015-08-04T14:55:00.070" Title="Why isn't north Quebec a little warmer?" Tags="|climatology|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5014" PostTypeId="2" ParentId="5008" CreationDate="2015-06-21T00:33:22.630" Score="2" Body="&lt;p&gt;There are entire chapters dedicated to this topic in physical geography and meteorology books; I doubt we could even scratch the surface here.  But in addition to what Fred mentioned (good stuff, btw) there are two polar highs and the equatorial low, which are thermally produced.  That is, the polar highs are high pressure because it's really cold and cold air sinks, and the equator is really hot and hot air rises.  At the poles, the cold air flows towards the warmer temperate zones and eventually warms sufficiently to rise, producing a low pressure area.  Likewise, the equatorial air flows toward the cooler zones and eventually cools sufficiently to sink, producing a high pressure area.  These are called Hadley Cells.&lt;br&gt;&lt;br&gt;The tilt of the earth and the changing seasons cause the position of these Hadley Cells to move, which is why the Eastern Pacific High and the Aleutian Low usually move south during the northern hemisphere winter.  (I say &quot;usually&quot; because they have pretty much not budged for the past three winters.)  I don't know the names of all the semi-permanent pressure zones, but they mostly follow the sun (okay, it really doesn't move) north and south as the seasons change.&lt;br&gt;&lt;br&gt;This is way over simplified, and the variables so numerous an entire book could be written just about them.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2015-06-21T00:33:22.630" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5015" PostTypeId="1" AcceptedAnswerId="5020" CreationDate="2015-06-21T01:13:14.457" Score="3" ViewCount="13039" Body="&lt;p&gt;I'm looking at a historical weather data report and the TMAX and TMIN are like this: 44 and -21, the following day 72 and 17. First I thought it was Fahrenheit, but the conversion didn't make any sense because it would be +6&amp;deg;C one day and +22&amp;deg;C the following day in January in NY, NY.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Then the note said  - &lt;strong&gt;* Values denoted with “*&lt;/strong&gt;” (i.e. temperature&#xA;  values) are in Celsius degrees to tenths on csv.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Does it mean 44 is actually 4.4 and 72 is 7.2? That would make much more sense.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More examples TMAX/TMIN:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;44/-21, 72/17, 83/-10, 128/61, 106/-49, -49/-71&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;PS. I know there is a possible duplicate that MAY have an answer to my question, unfortunately it doesn't. Some comments (not the answer itself or the question) explain WHY it is the case in vague and guessing terms, but it doesn't give an answer to WHAT it is, which is my question. Nobody can say for sure if 44 is 4.4 and -21 is -2.1 and I can't rely on guesses.&lt;/p&gt;&#xA;" OwnerUserId="3055" LastEditorUserId="111" LastEditDate="2016-07-05T02:43:34.640" LastActivityDate="2016-07-05T02:43:34.640" Title="What is Celsius degrees to tenths?" Tags="|temperature|" AnswerCount="2" CommentCount="1" ClosedDate="2015-06-21T22:29:33.190" ContentLicense="CC BY-SA 3.0" />
  <row Id="5016" PostTypeId="2" ParentId="5015" CreationDate="2015-06-21T02:24:15.827" Score="3" Body="&lt;p&gt;Your question is similar to this one: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4656/deciphering-ncdc-data/4657#comment8343_4657&quot;&gt;Deciphering NCDC data&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the comments for that question I posted the following two comments which will most likely answer your questions:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;regarding the usage of tenths of a degree, it may be a continuation of an ancient data format from the early era of computers. Removing decimal points changes numbers to integers. In old computers memory capacity &amp;amp; calculating speed was an issue. In binary digits, integers are half the size of floating point numbers &amp;amp; a quarter the size of double precision numbers. Hence the use of integers speeds up calculations &amp;amp; requires less memory (disk drives, tape &amp;amp; RAM) than floating point numbers. In the old days, tape was used heavily as an external storage medium&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;There is logic in maintaining the old data format for consistency. If the data format was changed then all the old data would need to be changed &amp;amp; checked to ensure there were no errors. If the format was changed as of a certain date but the old data remained in the old format, people would need to be mindful of the change &amp;amp; when it occurred. Analysis apps would need to first check if the data was from before or after the date of change, condition the data accordingly before doing the calculations. It's easier to keep the old format&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-06-21T02:24:15.827" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5017" PostTypeId="1" CreationDate="2015-06-21T06:19:01.133" Score="4" ViewCount="221" Body="&lt;p&gt;I'm tying to find any clue about the timescale of the biological pump. That the carbon is recycled to the surface ca. 1,000 years is clear but the timescale of the biological pump seems hard to find. There is an report I saw when I was surfing the internet saying that the timescale can range from 45 days to 5 years which I find is a little shocking. Does it truly vary that much, or there is something wrong about the data?&lt;/p&gt;&#xA;" OwnerUserId="3053" LastActivityDate="2015-06-23T08:27:20.650" Title="Timescale of the biological pump？" Tags="|ocean|oceanography|carbon-cycle|carbon|biogeochemistry|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5018" PostTypeId="1" CreationDate="2015-06-21T09:19:19.803" Score="5" ViewCount="21460" Body="&lt;p&gt;I am trying to figure out the difference between a carbon sink and a carbon reservoir.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The definition for a carbon sink from Wikipedia is &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;carbon sink is a natural or artificial reservoir that accumulates and stores some carbon-containing chemical compound for an indefinite period. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And the definition for carbon reservoir is &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Carbon-storing natural feature (such as a forest or the land mass) that exchanges carbon with other reservoirs.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My textbook says that mature forests are carbon reservoirs but they are not carbon sinks. So what is the difference between a carbon sink and a carbon reservoir on earth?&lt;/p&gt;&#xA;" OwnerUserId="3053" LastEditorUserId="6129" LastEditDate="2020-05-08T06:11:34.303" LastActivityDate="2024-02-05T16:48:17.553" Title="What is the difference between a carbon sink and a carbon reservoir?" Tags="|carbon-cycle|carbon|biogeochemistry|forest|atmospheric-chemistry|" AnswerCount="4" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="5019" PostTypeId="2" ParentId="5018" CreationDate="2015-06-21T12:11:50.630" Score="7" Body="&lt;p&gt;The difference is that a carbon sink &lt;strong&gt;accumulates&lt;/strong&gt; carbon, whereas a carbon reservoir &lt;strong&gt;has accumulated&lt;/strong&gt; carbon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is to say:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A carbon sink is an ongoing process which is increasing the amount of carbon stored in it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whereas although a carbon reservoir might exchange individual carbon-based molecules with other parts of the carbon cycle, as much will go out as goes in, keeping the amount of carbon in the reservoir broadly constant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both of these contrast with things such as coal seams and natural gas &amp;amp; crude oil reservoirs that humans have tapped as sources of fuel; and leakages of methane from the ground: these &lt;em&gt;were&lt;/em&gt; carbon reservoirs until the amount of carbon in them began depleting (e.g. through mining, well-drilling, or - in the case of methane clathrate leakages - ice melt), at which point they became carbon sources.&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="100" LastEditDate="2015-06-23T08:06:00.853" LastActivityDate="2015-06-23T08:06:00.853" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5020" PostTypeId="2" ParentId="5015" CreationDate="2015-06-21T15:59:24.560" Score="2" Body="&lt;p&gt;I looked up the actual data in Celsius and compared to what I have and yes 44 is 4.4 and -21 is -2.1.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When it says Celsius degrees to tenths you have to divide it by 10 and you will get the actual temperature.&lt;/p&gt;&#xA;" OwnerUserId="3055" LastActivityDate="2015-06-21T15:59:24.560" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5021" PostTypeId="1" CreationDate="2015-06-21T22:32:45.927" Score="8" ViewCount="11667" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/yZuxn.png&quot; alt=&quot;Long Term Climate&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I noticed that the $\ce{CO2}$ is actually decreasing in the eon time. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My guess is lush vegetation or forests began to grow which absorbed the $\ce{CO2}$ by photosynthesis?  Would anyone give me any clue?&lt;/p&gt;&#xA;" OwnerUserId="3053" LastEditorDisplayName="user2872" LastEditDate="2015-08-05T10:40:13.640" LastActivityDate="2019-06-26T14:44:53.007" Title="Why has CO2 decreased in the history of the Earth?" Tags="|atmosphere|climate|carbon-cycle|climate-models|carbon|" AnswerCount="4" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5022" PostTypeId="2" ParentId="5021" CreationDate="2015-06-21T22:54:18.537" Score="2" Body="&lt;p&gt;Also less volcanism from the crust thickening due to the Earth cooling and the land becoming available to photosynthesizers when the oxygen caused the ozone layer. Heat would cause more $\ce{CO2}$ in the air than today which makes it hotter still until Earth's heat radiation gets strong enough. It was hot at first from all the lava and the volcanic $\ce{CO2}$ overpowering the weaker sun. When it got cooler however, temperatures caused more $\ce{CO2}$ to be incorporated into carbonate rocks and plowed back into the mantle when their plates subducted. There's still chalk on the ground from when dinosaurs roamed a warmer Earth but a lot of that huge $\ce{CO2}$ atmosphere is in the mantle thanks to plate tectonics.&lt;/p&gt;&#xA;" OwnerUserId="3024" LastEditorDisplayName="user2872" LastEditDate="2015-07-17T14:30:48.660" LastActivityDate="2015-07-17T14:30:48.660" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="5023" PostTypeId="1" AcceptedAnswerId="5025" CreationDate="2015-06-22T08:37:02.503" Score="8" ViewCount="2786" Body="&lt;p&gt;It seems that seismic amplitude extracted on an interpreted horizon is good for showing channels. E.g.:&lt;a href=&quot;http://seismicatlas.org/entity?id=98a83c60-ea81-47cc-9304-6041f6ec5277&quot;&gt;http://seismicatlas.org/entity?id=98a83c60-ea81-47cc-9304-6041f6ec5277&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems that often the RMS amplitude is used instead.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;When do one use amplitude and when do one use RMS amplitude?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When using RMS amplitude one must integrate over a window around the horizon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Which window do one use?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I often see images of RMS amplitude maps where the caption simply says something like &quot;lower tertiary horizon with RMS amplitude extraction&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does this mean RMS calculated over a window from z =horizon - 10 m to horizon + 10 m for instance? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or could it mean RMS calculated over a window from z = 3 peaks above horizon to 3 peaks below horizon? &lt;/p&gt;&#xA;" OwnerUserId="3056" LastActivityDate="2015-06-22T12:29:59.360" Title="How do I extract seismic amplitude on an interpreted horizon?" Tags="|geophysics|seismic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5024" PostTypeId="2" ParentId="3063" CreationDate="2015-06-22T11:52:14.373" Score="-1" Body="&lt;p&gt;The color of the sky in Norway was greenish.&#xA;In the Netherlands it was just blue.&#xA;I saw this on my vacation to Norway around 1990.&#xA;I supposed the sky in Norway was more greenish because of the large woods.&#xA;So I suppose the color of the sky is also due to the reflection in it of what is on the ground.&#xA;Presumably the sky in a large desert will cary the color reflection of the sand.&#xA;Also the draining (partly) of the IJselmeer, a large Sea in the Netherlands caused the light in the sky supposedly to have become different.&#xA;As I remember, less bright.&lt;/p&gt;&#xA;" OwnerUserId="3057" LastEditorUserId="64" LastEditDate="2015-06-23T00:59:34.150" LastActivityDate="2015-06-23T00:59:34.150" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5025" PostTypeId="2" ParentId="5023" CreationDate="2015-06-22T12:29:59.360" Score="6" Body="&lt;p&gt;&lt;strong&gt;The answer to most of your questions is: it depends.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;h3&gt;Is amplitude good for mapping channels?&lt;/h3&gt;&#xA;&lt;p&gt;Amplitude maps &lt;em&gt;can&lt;/em&gt; be great for finding and interpreting channel systems. It depends on the geology and on the seismic data's characteristics. Sometimes you can just see the channels, which might be qualitatively useful, and sometimes you can infer quantitative information, such as width, thickness, composition, porosity, or fluid content. It depends.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.subsurfwiki.org/wiki/Attribute_analysis&quot; rel=&quot;noreferrer&quot;&gt;Here's a workflow for any kind of attribute analysis.&lt;/a&gt; I'll try to add to it in the next day or two.&lt;/p&gt;&#xA;&lt;h3&gt;When should I use RMS amplitude?&lt;/h3&gt;&#xA;&lt;p&gt;Before confusing yourself with what others do (they are not necessarily a good guide), it's worth reading about &lt;a href=&quot;http://subsurfwiki.org/wiki/Average&quot; rel=&quot;noreferrer&quot;&gt;different kinds of average&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The main feature of the RMS average, for geophysicists anyway, is that it works on zero-mean data like seismic:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/iWb7P.png&quot; alt=&quot;RMS amplitude for a seismic trace&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;So it's not really that &amp;quot;when using RMS amplitude one must integrate over a window&amp;quot;, more that if you want to measure amplitude over a window, you must use RMS.&lt;/p&gt;&#xA;&lt;p&gt;Because the values are squared, RMS has two other features (or bugs, depending on your point of view): large values are emphasized, and noise may therefore be emphasized.&lt;/p&gt;&#xA;&lt;p&gt;An alternative is to use the envelope of the trace (sometimes also called 'energy' or 'absolute amplitude'), which is the magnitude of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hilbert_transform&quot; rel=&quot;noreferrer&quot;&gt;Hilbert transform&lt;/a&gt; (also called 'complex trace'). It is always positive and has the added benefit of being phase-independent. &lt;a href=&quot;http://www.agilegeoscience.com/blog/2011/3/23/e-is-for-envelope.html&quot; rel=&quot;noreferrer&quot;&gt;Read more about envelope.&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;h3&gt;Which window to use?&lt;/h3&gt;&#xA;&lt;p&gt;Let the expected geology and basic geophysics and statistics guide all of your decisions. Use a window that captures the interval of interest (look at the wells!) without too much non-interesting stratigraphy. But use a big enough window that you don't see a lot of artifacts from large amplitude values coming in and out of the window (this also depends on the quality of the horizons and smoothness of the geology).&lt;/p&gt;&#xA;&lt;p&gt;Windows don't have to be symmetrical about a horizon. It depends where the features you're interested in are. In my experience, stratigraphic windows are often useful — from one horizon to the next. If you're interested in the horizon itself, consider just using its amplitude directly. If it's too noisy, try improving the pick or smoothing the amplitude map, before confusing things by throwing more geology in there.&lt;/p&gt;&#xA;&lt;h3&gt;What does that caption mean?&lt;/h3&gt;&#xA;&lt;p&gt;Who knows what that caption means? Vague captions plague the geophysics literature. Don't be part of the problem! If only for the sake of your future self, record the exact statistic and its parameters on every image — even put it all in the filename.&lt;/p&gt;&#xA;&lt;h3&gt;Remember what you're trying to do&lt;/h3&gt;&#xA;&lt;p&gt;You're trying to relate the seismic to reservoir properties you care about. This means proving that the property is related to the seismic in as quantitative way as possible. A nice way to do this is to crossplot the property with the seismic attribute — that way you also know the error of the estimate. A map showing wiggly channels is interesting, but nowhere near enough.&lt;/p&gt;&#xA;&lt;p&gt;I tend not to believe attribute analyses that don't include a crossplot.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-06-22T12:29:59.360" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5028" PostTypeId="2" ParentId="3063" CreationDate="2015-06-22T22:32:23.897" Score="0" Body="&lt;p&gt;Look near the Sun on a humid summer noon and then look at it after a strong cold front clears and tell me the sky is the same everywhere on Earth. Make sure your eyeballs are in shadow when you do this.&lt;/p&gt;&#xA;" OwnerUserId="3024" LastActivityDate="2015-06-22T22:32:23.897" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5030" PostTypeId="2" ParentId="5021" CreationDate="2015-06-23T00:10:16.277" Score="1" Body="&lt;p&gt;There's a number of things to consider, and, I'm just a layman who's read up on this a little as a hobby.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Solar wind and magnetic field.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We've all heard about Mars losing it's atmosphere to the Solar wind.   Young earth may have lost some of it's early atmosphere to the solar wind too - certainly some of the H2 in the chart in the original question.   He as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth's magnetic field formed some 3.5 billion years ago.   The earth had to cool down enough for the inner core to become solid for the magnetic field to form.   Also, that first 1.1 billion years of the solar system, the sun probobly had more frequent and stronger solar wind.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://www.wired.com/2010/03/earths-magnetic-field-is-35-billion-years-old/&quot; rel=&quot;nofollow&quot;&gt;http://www.wired.com/2010/03/earths-magnetic-field-is-35-billion-years-old/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So for the first 1.1 billion years, the Solar wind was probobly the primary factor in affecting the earth's atmosphere.   Also, if we begin the study around the time of the formation of the moon, the late heavy bombardment likely also brought frozen gas to the earth.   The young solar system was a chaotic place.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Following the formation of the magnetic field and the end of the late heavy bombardment (some of those asteroids may have vaporized the entirety of the earth's oceans for a time), then life became the driving factor in atmospheric changes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oxygen is the one we care about, but it wasn't the first.   Early forms of photosynthesis probobly included sulfur and likely all of it took place in the oceans.   There's not much dissolved gas in the oceans but there's enough that over hundreds of millions of years, this would have an effect.   Needless to say, once Oxygen photosynthesis started, that had a bigger effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oxygen photosynthesis may have started around 2.7 billion years ago and that was huge in taking and using CO2 dissolved in the ocean (but ultimately from the atmosphere) and releasing O2.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://www.scientificamerican.com/article/timeline-of-photosynthesis-on-earth/&quot; rel=&quot;nofollow&quot;&gt;http://www.scientificamerican.com/article/timeline-of-photosynthesis-on-earth/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Initially the released O2 bonded with Iron dissolved in the oceans and later, when released into the atmosphere (about 2.3-2.4 billion years ago), it likely reacted with and removed any remaining CH4 (Methane) in earth's atmosphere and perhaps any NH3 (Ammonia).   The dissolved O2 helped make the oceans clear but it also posed a problem for primitive bacteria that found dissolved oxygen far to reactive and this led to further evolution, life protecting itself from oxygen, and in time, this also lead to the ozone layer which helped early life move to the land.   Oxygen was also useful in forming granite, which was lighter than Basalt and this created more permanent and higher continents.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But to your question, what's important is that some bacteria died and fell to the ocean floor and this is where most of the early CO2 went, it formed layers on the ocean floor that over time became rock.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source:  &lt;a href=&quot;http://www.washingtonpost.com/national/health-science/bacterial-traces-from-35-billion-years-ago-are-oldest-fossils-experts-say/2012/12/27/9261e02c-4acb-11e2-9a42-d1ce6d0ed278_story.html&quot; rel=&quot;nofollow&quot;&gt;http://www.washingtonpost.com/national/health-science/bacterial-traces-from-35-billion-years-ago-are-oldest-fossils-experts-say/2012/12/27/9261e02c-4acb-11e2-9a42-d1ce6d0ed278_story.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the first forests came, about 400 million years ago, they also played a role in trapping and storing CO2 and further reducing CO2 content in the atmosphere, but by then, much of the CO2 from 3 billion years earlier was already absorbed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tectonic forces do return some of this trapped gas back into the atmosphere, but over time, (I think - the articles on this seem both a little mixed and often complicated), but I think the tendency is for a planet with life on it, to gradually trap more and more of it's atmosphere leading not only to a decreasing CO2 content but also a lower atmospheric pressure over geological periods of time.   One possible example of this is the Pterodactyl, which, in order to fly, it probobly would need a thicker atmosphere than we have today.   Insects also tell us a bit about past atmospheric pressure.   Insects don't have lungs, so their size is limited by the available oxygen that flows into their bodies through tracheae.   Bigger insects imply 2 things, higher oxygen content and/or higher atmospheric pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, more specifics and shorter term changes: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;ItsMyPostAndIllWriteIfIWn, is correct about oceanic storage of atmospheric gases being affected by temperature, but I have a hard time seeing that as playing a major role on a geological scale, though it certainly has an effect on CO2 content today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Major volcanic events, like the one 250 million years ago over Siberia or perhaps the one 66 million years ago over India might have burned sufficient coal and trapped carbon deposits to measurably change the atmosphere and CO2 content, but I think those changes were more temporary (though the one 250 million years ago was enormous, that might have made a significant longer lasting change).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also natural disasters like the oceans growing stagnant and releasing H2S - which is very bad for life on land, or the oceans releasing huge amounts of CH4 would also have short term effects on atmospheric content - so there's a whole lot of moving parts to this question, depending on how close you want to look at it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Footnote - I'm only a hobbyist, not a professor with a degree in this subject.  It's a complicated field with a lot of moving parts.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2015-06-23T00:10:16.277" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5031" PostTypeId="2" ParentId="5018" CreationDate="2015-06-23T01:04:42.870" Score="4" Body="&lt;p&gt;A carbon reservoir is measured by the amount of carbon it contains, for example kilograms of carbon [kg C]. A carbon source or sink is measured by the amount that comes out or into the reservoir from the rest of the system per unit of time, for example kilograms per day [kg C/day]. A coal or oil deposit can be either a reservoir or source, as carbon flows out (it's a source as product is extracted) the size of the reservoir decreases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because carbon (or any element) is a conserved quantity, if your peat bog is growing larger, then it may be a &lt;em&gt;net sink&lt;/em&gt; for carbon.  But if is losing carbon to the atmosphere (say as methane or if it is a burning peat bog) as deposition of organic material continues, the reservoir may not be growing and the bog could be a &lt;em&gt;net source&lt;/em&gt; of carbon to the rest of the system. (I really don't know how real peat deposits behave.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In mathematical transport-models, you can specify sources and sinks without specifying a reservoir, but in actual systems there has to be reservoirs to provide or take-up whatever element is being transported.  &lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorUserId="178" LastEditDate="2015-06-23T04:32:49.150" LastActivityDate="2015-06-23T04:32:49.150" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5033" PostTypeId="1" AcceptedAnswerId="5039" CreationDate="2015-06-23T07:25:36.517" Score="10" ViewCount="14092" Body="&lt;p&gt;I am using a data set from Justin Sheffield at Princeton that includes specific humidity. The description is as follows:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Reanalysis 6-hourly specific humidity interpolated to 1.0deg with account for elevation changes and scaled to maintain consistency with reanalysis relative humidity and CRU TS3.0 monthly air temperature&quot;;&lt;br&gt;&#xA;  The units are = &quot;kg kg-1&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What does this mean? Does it mean kg/kg so essentially dimensionless? Because I have seen around specific humidity measured also in g/kg, maybe that was wrong? &#xA;These two pages give the same definition of specific and absolute humidity, I thought they were different things: &#xA;&lt;a href=&quot;http://www.nzifst.org.nz/unitoperations/drying3.htm&quot;&gt;http://www.nzifst.org.nz/unitoperations/drying3.htm&lt;/a&gt;&#xA;&lt;a href=&quot;http://tigge.ecmwf.int/tigge/d/show_object/table=parameters/name=specific_humidity/levtype=pl/&quot;&gt;http://tigge.ecmwf.int/tigge/d/show_object/table=parameters/name=specific_humidity/levtype=pl/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3061" LastEditorUserId="87" LastEditDate="2015-06-23T07:54:27.537" LastActivityDate="2018-02-27T09:09:51.283" Title="What does the notation &quot;kg kg-1&quot; for units mean for specific humidity" Tags="|meteorology|atmosphere|humidity|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5034" PostTypeId="1" AcceptedAnswerId="5041" CreationDate="2015-06-23T08:19:33.030" Score="9" ViewCount="647" Body="&lt;p&gt;I am a software developer trying to learn applied geophysics. Specifically I am interested in seismic attributes. I have a strong background in mathematics and signal processing and therefore grasp the theory quite easily. However the geology and the applied part is a problem for me. What i would like is a book/tutorial that takes the reader trough very detailed concrete examples with no theory whatsoever. Any suggestions?&lt;/p&gt;&#xA;" OwnerUserId="3056" LastActivityDate="2015-06-23T15:59:47.367" Title="Books for learning applied seismic geophysics" Tags="|geophysics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5035" PostTypeId="2" ParentId="5017" CreationDate="2015-06-23T08:27:20.650" Score="3" Body="&lt;p&gt;I'm going to answer assuming you are referring to the time between the moment when the organism absorbs the carbon and the moment when it is trapped in sediments. I'm also going to answer by talking about what I know best, i. e. diatoms, which happens to be the major component of the biological pump.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The variation you are referring to is consistent with the fact that coastal diatoms only have a few hundred meters to sink before reaching the seafloor, whereas open-ocean diatoms are sinking for ca. 1000 to 5000 meters.&#xA;According to a compilation by &lt;strong&gt;Lisitzin (1972)&lt;/strong&gt;, so arguably a little dated, the settling velocity of marine diatoms in the water column is only of a few meters per day (he advances the number of 0.2 to 1.2m/day for 20 to 50µm-sized marine diatoms). But it can vary according to many factors and some of the coarsest, heaviest forms (such as resting spores) or diatoms that travel down in fecal pellets of copepods can be faster and reach the seafloor in an open ocean setting in only a few hundred days.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We don't usually consider this as being part of the biological pump sensu stricto but of course most of the organic matters created by diatoms from atmospheric CO&lt;sub&gt;2&lt;/sub&gt; is recycled by the zooplankton that grazes on them, which is in turn recycled by what feeds on that zooplankton, etc. Eventually some of them will end up trapped in sediments as well. This lengthens the process of course.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Lisitzin, A. P., 1972. &lt;em&gt;Sedimentation in the world ocean.&lt;/em&gt; Society of Economic Paleontologists and Mineralogists, Special Publication 17: 218pp.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastActivityDate="2015-06-23T08:27:20.650" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5036" PostTypeId="2" ParentId="5033" CreationDate="2015-06-23T08:33:18.053" Score="12" Body="&lt;p&gt;Yes, the unit is kilogram per kilogram, but it means kilogram of water (moisture) per kilogram of air.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-06-23T08:33:18.053" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5037" PostTypeId="2" ParentId="5033" CreationDate="2015-06-23T11:17:45.000" Score="5" Body="&lt;p&gt;The basic idea is that by mentioning $\mathrm{kg}\, \mathrm{kg}^{-1}$ you make it clear that you measure the weight. You can think of it as&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ 0.01\, \mathrm{kg}\, \mathrm{kg}^{-1} = 1\, \mathrm{wt.}\%. $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is to avoid confusion with $\mathrm{vol.}\,\%$.&lt;/p&gt;&#xA;" OwnerUserId="99" LastActivityDate="2015-06-23T11:17:45.000" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5038" PostTypeId="1" CreationDate="2015-06-23T13:23:54.400" Score="5" ViewCount="444" Body="&lt;p&gt;has anyone used the python code from &lt;a href=&quot;https://code.google.com/p/pywrfplot/source/browse/#svn%2Ftrunk&quot; rel=&quot;nofollow noreferrer&quot;&gt;here (written by Geir Arne Waagbo)&lt;/a&gt; to plot skewT plot from WRF output?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've got a question regarding some of the functions used in the code found in pywrfplotUtils.py - which is the getXY(lon,lat) function that gets called in getDimensions(nc) function.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Below are the codes:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;def getDimensions(nc):&#xA; Nx = nc.getncattr('WEST-EAST_GRID_DIMENSION')-1&#xA; Ny = nc.getncattr('SOUTH-NORTH_GRID_DIMENTION')-1&#xA; Nz = nc.getncattr('BOTTOM-TOP_GRID_DIMENSION')-1&#xA; dx = nc.getncattr('DX')&#xA; dy = nc.getncattr('DY')&#xA; lons = nc.variables['XLAT'][0]&#xA; lats = nc.variables['XLONG'][0]&#xA; # find coordinates for focus point&#xA; x,y = getXY(lons[Ny/2,:],lats[:,Nx/2])&#xA; return Nx,Ny,Nz,lons,lats,dx,dy,x,y&#xA;&#xA;def getXY(lon,lat):&#xA; x_nr = 0&#xA; y_nr = 0&#xA; while (lon[x_nr] &amp;lt; lon_focuspoint):&#xA;  x_nr += 1&#xA; while (lat[y_nr] &amp;lt; lat_focuspoint):&#xA;  y_nr += 1&#xA;&#xA; print &quot;x_nr:&quot; str(x_nr),&quot;Lon:&quot;,str(lon[x_nr])&#xA; print &quot;y_nr:&quot; str(y_nr),&quot;Lat:&quot;,str(lon[x_nr])&#xA; return x_nr,y_nr&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The focus point is a variable set in the pywrfplotParams.py:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;#This defines the grid box for which skewT-plots etc are based&#xA;lat_focuspoint = 60.2&#xA;lon_focuspoint = 11.08&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, I don't know what focus point is referring to, so when I use the values set by the author, obviously I get an error, and that error is - &lt;em&gt;IndexError: index out of bounds.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have found this &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2732/how-to-get-cell-indices-from-latitude-and-longitude-in-wrf-model-grids&quot;&gt;link&lt;/a&gt; useful in providing the definition for the attributes asked in that question, but I'm not entirely sure if I should also get the cell indices from latitude and longitude in the WRF model grids.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your thoughts are very much appreciated!&lt;/p&gt;&#xA;" OwnerUserId="3063" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-06-23T14:19:26.743" Title="What is &quot;focus point&quot; in WRF-plots grid box? (python code)" Tags="|meteorology|numerical-modelling|wrf|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5039" PostTypeId="2" ParentId="5033" CreationDate="2015-06-23T13:56:01.907" Score="6" Body="&lt;p&gt;Just to expand on yo's answer:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's unit-less so, mathematically, you could omit the kg/kg. However then the reader wouldn't know if you're expressing a quantity as a percent weight or a percent volume which are different. &lt;/p&gt;&#xA;" OwnerDisplayName="user3065" LastActivityDate="2015-06-23T13:56:01.907" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5040" PostTypeId="2" ParentId="5038" CreationDate="2015-06-23T14:19:26.743" Score="2" Body="&lt;p&gt;A Skew-T/Log-p plot is a vertical profile from a point, and it appears in that code that the point you are plotting the skew-T for is 60.2 latitude, 11.08 longitude.  The snippet of code:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;def getXY(lon,lat):&#xA; x_nr = 0&#xA; y_nr = 0&#xA; while (lon[x_nr] &amp;lt; lon_focuspoint):&#xA;  x_nr += 1&#xA; while (lat[y_nr] &amp;lt; lat_focuspoint):&#xA;  y_nr += 1&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;finds the closest grid point west and south of your focus point by setting the x and y gridpoints to 0 and incrementing the index as long as the latitude/longitude values at that grid point are less than the focus point.  This is what the focus point is for -- the lat/lon location you want the skew-t/log-p plot at.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The exception &lt;code&gt;IndexError: index out of bounds.&lt;/code&gt; means that the above code tried to access a value &lt;code&gt;lon[x_nr]&lt;/code&gt; or &lt;code&gt;lat[y_nr]&lt;/code&gt; that was out of bounds.  This means that the latitude/longitude coordinate of your focus point is not within your domain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To run the code successfully, edit the focus point to be a point within your model domain, specifically the value of latitude and longitude that you want the skew-t profile for.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-06-23T14:19:26.743" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="5041" PostTypeId="2" ParentId="5034" CreationDate="2015-06-23T15:59:47.367" Score="7" Body="&lt;p&gt;Here's a list of resources I've compiled before. Between them, maybe you'll find what you're after:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Some important geophysics papers and books: &lt;a href=&quot;http://subsurfwiki.org/wiki/Must-read_geophysics&quot;&gt;Must-read geophysics&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.agilegeoscience.com/blog/2013/3/31/six-books-about-seismic-interpretation.html&quot;&gt;Six books about seismic interpretation&lt;/a&gt; — most of these include something about seismic attributes.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.agilegeoscience.com/blog/2014/7/18/six-books-about-seismic-analysis.html&quot;&gt;Six books about seismic analysis&lt;/a&gt; — more quantitative, and usually with lots of theory. I especially recommend Simm &amp;amp; Bacon. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I recommend learning what you can about rocks — their genesis, their properties, and especially their acoustic and elastic behaviour. If possible, go and see outcrops or at least cores. If possible, take classes in sedimentology, petrology, or even reservoir engineering.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You need to read about &lt;em&gt;integrated interpretation&lt;/em&gt;; here are some other phrases to look for: &lt;em&gt;well ties&lt;/em&gt;, &lt;em&gt;phase estimation&lt;/em&gt;, &lt;em&gt;spectral decomposition&lt;/em&gt;, &lt;em&gt;seismic inversion&lt;/em&gt;, &lt;em&gt;pre-stack seismic analysis&lt;/em&gt;, &lt;em&gt;AVO&lt;/em&gt;. I recommend subscribing to &lt;a href=&quot;http://csegrecorder.com/&quot;&gt;CSEG &lt;em&gt;Recorder&lt;/em&gt;&lt;/a&gt;, &lt;a href=&quot;http://fb.eage.org/&quot;&gt;EAGE &lt;em&gt;First Break&lt;/em&gt;&lt;/a&gt; and &lt;a href=&quot;http://library.seg.org/journal/tle&quot;&gt;SEG &lt;em&gt;Leading Edge&lt;/em&gt;&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Good luck in your quest!&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-06-23T15:59:47.367" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5042" PostTypeId="1" AcceptedAnswerId="5043" CreationDate="2015-06-23T16:25:18.377" Score="16" ViewCount="4685" Body="&lt;p&gt;Someone shared a video with me in which clouds were forming a ring around the Sun. I took this screen shot of that video:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/IRzV1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the reason behind this?&lt;/p&gt;&#xA;" OwnerUserId="3066" LastEditorUserId="124" LastEditDate="2016-02-06T11:57:29.023" LastActivityDate="2016-02-06T11:57:29.023" Title="Why do clouds sometimes form a ring around the Sun?" Tags="|meteorology|clouds|atmospheric-optics|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="5043" PostTypeId="2" ParentId="5042" CreationDate="2015-06-23T16:44:53.093" Score="24" Body="&lt;p&gt;This optical phenomenon is called a &lt;a href=&quot;https://en.wikipedia.org/wiki/22%C2%B0_halo&quot; rel=&quot;noreferrer&quot;&gt;22° halo&lt;/a&gt; which is a subset of other &lt;a href=&quot;https://en.wikipedia.org/wiki/Halo_(optical_phenomenon)&quot; rel=&quot;noreferrer&quot;&gt;halos&lt;/a&gt;.  This arises from sunlight refracting through hexagonal ice crystals, which can be found in high level cirrus clouds.  Light that would otherwise not make it to your eye enters an ice crystal and then exits at an angle of approximately 22 degrees.  This produces the arc of light you see in the video.  You see (inverted) rainbow coloring of the halo because the light is not uniformly refracted but varies from 21.7 degrees for red photons to 22.5 degrees for violet photons.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/4gojQ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;br&gt;&#xA;&lt;sub&gt;Image by donalbein, Wikemedia Commons, CC-By-SA-2.5 &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Path_of_rays_in_a_hexagonal_prism.png&quot; rel=&quot;noreferrer&quot;&gt;https://commons.wikimedia.org/wiki/File:Path_of_rays_in_a_hexagonal_prism.png&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are many more optical phenomenon you can see, but all are based around sunlight and the optical properties of ice crystals and water droplets.  Here is a phenomenal picture taken in winter showing many examples:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/kv1zw.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2015-06-23T21:24:15.213" LastActivityDate="2015-06-23T21:24:15.213" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5044" PostTypeId="1" CreationDate="2015-06-23T17:17:04.273" Score="18" ViewCount="2120" Body="&lt;p&gt;What causes the darker color of the clouds (nimbus) when it is about to rain? Non-precipitating clouds (e.g., cumulus, stratus) tend to be white, but rain clouds become gray and almost black before it rains. What is different in those clouds?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/I9KrG.jpg&quot; alt=&quot;cumulonimbus&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: Wikipedia commons.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="64" LastEditDate="2015-06-23T17:39:53.333" LastActivityDate="2017-07-09T08:43:17.557" Title="Why are clouds darker before it rains?" Tags="|meteorology|clouds|radiative-transfer|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5045" PostTypeId="2" ParentId="5044" CreationDate="2015-06-23T17:39:38.713" Score="18" Body="&lt;p&gt;Fair weather cumulus clouds are white because there is a clear path for sunlight to reflect off the cloud and into your eye.  Even when there are many of them, they are not vertically developed and photons can still scatter off of them to you.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As cumulus develop into towering cumulus and cumulonimbus they become horizontally widespread and quite high (the tops of severe convection overshoot into the stratosphere and the convection in the tropics can go even higher, owing to a higher tropopause).  A developed CB cloud also features an anvil.  These clouds are also optically thick, dense with cloudwater, rain, snow and ice.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a cloud to appear white, photons representing the full visible spectrum must be able to arrive at your eye.  For an optically thick cloud of appreciable thickness, transmission isn't an option.  Note that both the physical thickness and the density of the cloud will increase its optical thickness.  This means that if the cloud size doesn't change but more and bigger rain drops are in the cloud, it will be optically thicker and appear darker. If there isn't a path from the sun to a surface of the cloud you can see, scattering isn't an option.  Water emits in the infrared, so emission isn't an option.  If visible photons cannot arrive at your eye from the cloud, then the cloud will appear dark.  The presence of hydrometeors (rain drops, snow, hail) in a rain cloud will further decrease transmission and darken the cloud.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Putting it together, as that white cumulus grows and becomes tens of thousands of feet tall, it will still appear white if the sun is on your side of the cloud.  It will appear darker if the sun is behind the cloud (transmission through the cloud).  As the cloud becomes horizontally thick, transmission will decrease, darkening the cloud if you aren't in a position to observe scattering.  Once an anvil starts to form, if you are anywhere near the storm you are likely in shadow and there probably isn't a path for scattering sun-&gt;cloud-&gt;eye.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the picture you posted it appears the sun is behind the storm.  You can see the anvil in the upper left part of the image is bright white on its edge where you can see scattering from the sun.  As you see the anvil toward the storm it darkens because now you are seeing photons transmitted through the anvil, and less are making it to your eye.  The updraft is colored similarly, with some light areas with scattering and the bulk of the surface quite dark due to no scattering and low transmission.  Under the storm you see some bright clouds via scattering from the sun.  You can see this spectrum doesn't appear quite white, a consequence of different wavelengths scattering differently (and this effect can give rise to the green aura people associate with hail, which is really just related to having tall storms causing long path lengths and multiple scattering necessary for photons to reach your eye).&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2015-06-29T12:24:16.267" LastActivityDate="2015-06-29T12:24:16.267" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5046" PostTypeId="2" ParentId="5042" CreationDate="2015-06-23T20:19:16.083" Score="6" Body="&lt;p&gt;There's no hole. Are you referring to the sky inside the halo looking darker than the sky outside? If so, the same phenomenon, known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Alexander%27s_band&quot;&gt;Alexander's band&lt;/a&gt;, happens with rainbows. The reason is that light can only deviate through a certain range of angles when it passes through the ice crystals that cause the halo. In particular, light can spread outwards from the halo, causing that area to be brighter because it's receiving more light and reflecting it to you, but not inwards, causing that area to appear darker.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The effect is reversed compared to rainbows, since rainbows are a reflection phenomenon, whereas haloes are a transmission phenomenon. That is, the halo is seen when you're facing the sun, with its light passing through the cloud; a rainbow is seen when you have your back to the sun, with its light reflecting from the water droplets. You'll notice that the halo has the red band on the inside, whereas a rainbow has the red band on the outside.&lt;/p&gt;&#xA;" OwnerUserId="240" LastActivityDate="2015-06-23T20:19:16.083" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5047" PostTypeId="1" AcceptedAnswerId="5048" CreationDate="2015-06-23T21:25:32.123" Score="30" ViewCount="61060" Body="&lt;p&gt;As far as I understand it is perfectly valid for air to have 100% humidity. At that point, all water can still exist in form of vapor, non-condensed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Does it immediately start to rain if humidity is &gt;100%?&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If so, why do we have slight rain and heavy rain if any 0.1% above 100% drops out immediately? That should always be only a small amount of rain and rainstorms could not be explained.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If not, what is the limit of humidity if not 100% and why can it exceed 100%? &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;I have tried to understand the &lt;a href=&quot;https://en.wikipedia.org/wiki/Humidity&quot;&gt;Wikipedia article&lt;/a&gt; but I'm stuck in various places:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Water vapor is the gaseous state of water and is invisible&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Invisible&lt;/em&gt; to me would mean that clouds are excluded from humidity.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Absolute humidity is the total mass of water vapor present in a given volume of air.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That again makes me think a cloud must be included.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The humidity is affected by winds and by rainfall.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Rainfall certainly decreases humidity, but it is not stated at what percentage it starts to rain.&lt;/p&gt;&#xA;" OwnerUserId="3071" LastEditorUserId="192" LastEditDate="2015-06-23T21:33:02.200" LastActivityDate="2018-06-20T12:33:12.433" Title="At what humidity does it start to rain?" Tags="|meteorology|humidity|rainfall|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="5048" PostTypeId="2" ParentId="5047" CreationDate="2015-06-23T23:55:10.880" Score="28" Body="&lt;p&gt;Short answer: humidity is not a proxy for rain starting and no, it does not start raining automatically when 100% humidity is reached (haze or clouds can form though).  The onset of rain is dependent on many things including humidity, but a specific value of humidity is not a sufficient condition for rain.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Water vapor is a gas and invisible.  The amount of water vapor in the air can be expressed as relative humidity (RH) which is the ratio of water vapor pressure ($e$) and saturation water vapor pressure ($e_s$).  Saturation vapor pressure is the partial pressure of vapor when evaporation and condensation rates are equal, represented by RH=100%.  When RH &gt; 100% net condensation occurs, but water has its own ideas.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a mixture of pure dry air and water vapor, water will not condense until around 400% RH.  Reasons for this are a bit complicated but it has to do with very small droplets being more likely to evaporate as their curvature is very large (&lt;a href=&quot;https://en.wikipedia.org/wiki/Kelvin_equation&quot;&gt;Kelvin effect&lt;/a&gt;, saturation vapor pressure is higher over curved surfaces than flat ones).  Luckily for us, our atmosphere is not pure air but has small particulates suspended in it (aerosols).  Some of these aerosols are classed as cloud condensation nuclei (CCN) and enable droplet formation at lower relative humidities.  These work by forming a solute in water increasing the energy needed to break bonds and evaporate the water (&lt;a href=&quot;https://en.wikipedia.org/wiki/Raoult%27s_law&quot;&gt;Raoult's_law&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The combined interaction of these are described by &lt;a href=&quot;https://en.wikipedia.org/wiki/K%C3%B6hler_theory&quot;&gt;Köhler theory&lt;/a&gt; and describe droplet growth in terms of drop size, solute and supersaturation (RH-100%).  In a nutshell, there is a critical drop size below which drop size decreases for decreasing supersaturation and above which drop size &lt;em&gt;increases&lt;/em&gt; for decreasing supersaturation.  The critical supersaturation is the supersaturation needed to attain the critical drop size, and is generally small (e.g. 0.3% supersaturation).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Droplets below the critical size are 'haze drops' and these make up the haze you see on very humid days.  Drops that reach the critical size can continue to grow to become cloud drops.  The condensed water is carried in the air but is no longer water vapor and is not part of relative humidity (but does contribute to the parcel density)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So... when does it rain?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It rains when water vapor is in the presence of CCN, driven to a supersaturation causing growth to the critical drop size (on the order of $\mu$m) and continuing to grow to cloud drops and further to the much bigger drop sizes that make up drizzle (100-300 $\mu$m)and rain drops(mm), a process that takes around 40 minutes.  Drops will grow until the updraft can no longer support their mass and then they fall from the cloud as rain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your question asks at what humidity does it rain, but what surface humidity determines is how high the cloud bases are.  When the dew point depression (the difference between temperature and dew point) is high, the cloud bases will be higher than when the dew point depression is small.  As air rises it cools, and at some point 100% RH is attained.  If there is forcing for vertical ascent, parcels can rise to this height and then to a height where they freely convect due to decreased parcel density caused by the release of energy during condensation (see: &lt;a href=&quot;https://en.wikipedia.org/wiki/Convective_available_potential_energy&quot;&gt;CAPE&lt;/a&gt;).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far to have rain we've needed water vapor (but not at 100% at the surface), aerosols to aid condensation (CCN) and a way to cool the air to reach 100% RH via lifting.  It is these three things -- moisture, aerosols and cooling, that we need for a rain storm.  We can have 100% RH days that are just hazy or foggy that do not rain and we can have days with mextremely little RH (e.g. deserts) that result in little rainstorms or large severe storms.  We also have storms we call 'elevated convection' that are completely disconnected from surface conditions and when these storms cause rain is not related to surface humidity at all.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are looking for a magic trigger for rain, your closest bet will be looking at temperature, dew point and the height parcels need to attain to freely convect (&lt;a href=&quot;https://en.wikipedia.org/wiki/Level_of_free_convection&quot;&gt;LFC&lt;/a&gt;).  If there is forcing for parcels to get that high and instability above, then rain is a good bet.  Forcing for lift can be anything from convergence along a boundary (sea breeze, cold front, outflow from another storm), orographic lifting (mountains, hills), thermally or dynamically forced.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;To address your specific concerns:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Water vapor is the gaseous state of water and is invisible&lt;/p&gt;&#xA;  &#xA;  &lt;blockquote&gt;&#xA;    &lt;p&gt;Invisible to me would mean that clouds are excluded from humidity.&lt;/p&gt;&#xA;  &lt;/blockquote&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Correct, clouds are not part of humidity, they are suspended liquid water drops, usually condensed onto a solute of some kind.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Absolute humidity is the total mass of water vapor present in a given volume of air.&lt;/p&gt;&#xA;  &#xA;  &lt;blockquote&gt;&#xA;    &lt;p&gt;That again makes me think a cloud must be included.&lt;/p&gt;&#xA;  &lt;/blockquote&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Water vapor contributes to humidity but water vapor does not include liquid water.  Cloud water, ice, snow, rain, grapple, hail all contribute to the total mass of a volume of air, but are not humidity.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The humidity is affected by winds and by rainfall.&lt;/p&gt;&#xA;  &#xA;  &lt;blockquote&gt;&#xA;    &lt;p&gt;Rainfall certainly decreases humidity, but it is not stated at what percentage it starts to rain.&lt;/p&gt;&#xA;  &lt;/blockquote&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Humidity will increase during a rainstorm as rain and puddles evaporate.  Temperature will decrease toward the wet bulb temperature.  As noted in the answer, there isn't a magic number of %humidity that causes rain to start.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2015-06-24T19:50:25.833" LastActivityDate="2015-06-24T19:50:25.833" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5049" PostTypeId="2" ParentId="5012" CreationDate="2015-06-24T00:33:50.493" Score="4" Body="&lt;h3&gt;Frequency&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Most high-power radio-frequency amplifiers (&lt;a href=&quot;https://en.wikipedia.org/wiki/Klystron&quot; rel=&quot;nofollow&quot;&gt;klystrons&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Cavity_magnetron&quot; rel=&quot;nofollow&quot;&gt;cavity magnetrons&lt;/a&gt;) have a very limited frequency range.  A dual-frequency radar would essentially be two radars hooked up to the same antenna.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Polarization&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Horizontally-polarized radar waves reflect more strongly from the ground than vertically-polarized waves, while circularly-polarized waves reflect only weakly from rain.  Consequently, vertical polarization gives the best results for weather radar.  A dual-polarization radar would sacrifice detail to eliminate range error.&lt;/p&gt;&#xA;" OwnerUserId="2643" LastActivityDate="2015-06-24T00:33:50.493" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5050" PostTypeId="1" AcceptedAnswerId="5051" CreationDate="2015-06-24T05:35:21.260" Score="4" ViewCount="5878" Body="&lt;p&gt;I am using NCEP_DOE reanalysis 2 data set. It include only relative humidity while I need specific humidity. How do I convert the relative humidity into specific humidity?&lt;/p&gt;&#xA;" OwnerUserId="3075" LastActivityDate="2015-06-24T07:07:14.247" Title="How do I convert Relative Humidity into specific humidity" Tags="|meteorology|atmosphere-modelling|" AnswerCount="1" CommentCount="1" ClosedDate="2015-07-03T22:37:54.967" ContentLicense="CC BY-SA 3.0" />
  <row Id="5051" PostTypeId="2" ParentId="5050" CreationDate="2015-06-24T07:07:14.247" Score="3" Body="&lt;p&gt;The &lt;a href=&quot;http://www.engineeringtoolbox.com/specific-relative-humidity-air-d_688.html&quot; rel=&quot;nofollow&quot;&gt;Engineering Toolbox&lt;/a&gt; gives the following equation for converting relative humidity to specific humidity.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If we know the relative humidity of the moist air and the water vapor density and density of the air, the specific humidity can be expressed as:&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;x = 0.622 φ ρws / (ρ - ρws) 100%         (1)&#xA;&#xA;where&#xA;&#xA;x = specific humidity of air vapor mixture (kg/kg)&#xA;&#xA;φ = relative humidity (%)&#xA;&#xA;ρws = density of water vapor (kg/m3)&#xA;&#xA;ρ = density of the moist or humid air (kg/m3)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-06-24T07:07:14.247" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5052" PostTypeId="1" AcceptedAnswerId="5059" CreationDate="2015-06-24T07:32:21.057" Score="6" ViewCount="1048" Body="&lt;p&gt;I am running a land biosphere model that uses meteorological data as drivers. The model has a threshold of 32g/kg for specific humidity. The data I am using taken from a reanalysis performed by J. Sheffield at Princeton has some values of S. Hum. higher than 32g/kg. Given that such data is of resolution of 1 degree and 3 hourly interpolated from 6-hour data, what is a typical range for S. Hum. in lowland tropical areas. I need to know this to deem if these data is close enough to the real world or if it includes unrealistic values I will consult the author and point out that data might be inaccurate for these regions. It is difficult to find online any direct measurements, I only find these big data sets such as NCAR-NCEP.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;edit: looking at a region of the Amazon, I see frequent values around the 30g/kg range, for example here &lt;a href=&quot;http://iridl.ldeo.columbia.edu/SOURCES/.NOAA/.NCEP-NCAR/.CDAS-1/.DAILY/.Intrinsic/.PressureLevel/P/1000/VALUE/ds:/qa/temp//celsius/unitconvert/u/a:/v/:a/mag/:ds/%28qa%29//var/parameter/interp/nip/DATA/AUTO/AUTO/RANGE/P/1000/VALUE/T/0.0/dekadalAverage/X/-180/0.5/180/GRID/X/360.0/makeperiodic/Y/-90/0.5/90/GRID/X/Y/fig-/colors/grey/verythin/mews_prov/black/thin/countries_gaz/-fig//T/last/plotvalue//antialias/true/psdef/index.html?layers=countries_gaz&amp;amp;layers=qa&amp;amp;T=21-30%20Jun%202013&amp;amp;bbox=bb%3A289.775%3A-10.432%3A308.296%3A0.734%3Abb#instructions&quot; rel=&quot;nofollow&quot;&gt;http://iridl.ldeo.columbia.edu/SOURCES/.NOAA/.NCEP-NCAR/.CDAS-1/.DAILY/.Intrinsic/.PressureLevel/P/1000/VALUE/ds:/qa/temp//celsius/unitconvert/u/a:/v/:a/mag/:ds/%28qa%29//var/parameter/interp/nip/DATA/AUTO/AUTO/RANGE/P/1000/VALUE/T/0.0/dekadalAverage/X/-180/0.5/180/GRID/X/360.0/makeperiodic/Y/-90/0.5/90/GRID/X/Y/fig-/colors/grey/verythin/mews_prov/black/thin/countries_gaz/-fig//T/last/plotvalue//antialias/true/psdef/index.html?layers=countries_gaz&amp;amp;layers=qa&amp;amp;T=21-30%20Jun%202013&amp;amp;bbox=bb%3A289.775%3A-10.432%3A308.296%3A0.734%3Abb#instructions&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3061" LastEditorUserId="3061" LastEditDate="2015-06-24T18:13:30.463" LastActivityDate="2015-06-24T18:15:46.920" Title="Specific humidity range in tropical lowlands?" Tags="|meteorology|climate-models|atmosphere-modelling|humidity|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5054" PostTypeId="1" CreationDate="2015-06-24T09:27:23.397" Score="3" ViewCount="209" Body="&lt;p&gt;At first run I’ve encountered the problem since the values of modeled and observed discharge are significantly different. &#xA;The correlation between them is nearly &lt;code&gt;0,2&lt;/code&gt; as the modeled discharge gives much higher values. &lt;br&gt;&#xA;I have already checked the precipitation file (it has some missing values which I substituted with zeros) and also did the correlation between the discharge and precipitation which showed the result nearly 0,35; while the cross correlation with three-day lag is &lt;code&gt;0,6&lt;/code&gt;. &lt;br&gt; &#xA;In addition, the model predicts the precipitation values very accurately, though the discharge is very high.&lt;br&gt;&#xA;&lt;strong&gt;How can I identify what is the conceptual logic behind the algorithm of inflow-outflow calculations in SWAT (or maybe refer me to the literature on the matter)&lt;/strong&gt; so I could go through the output again and identify the potential problem?&lt;br&gt;&lt;/p&gt;&#xA;" OwnerUserId="3080" LastActivityDate="2015-09-07T12:27:57.913" Title="High Discharge Value in SWAT modelling" Tags="|models|hydrology|ecology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5055" PostTypeId="1" CreationDate="2015-06-24T13:13:00.973" Score="5" ViewCount="922" Body="&lt;p&gt;If the atmosphere were cooled to liquid, say the planet's average atmospheric temperature were reduced to 70K, how deep (above sea level - frozen oceans of water) would the resulting ocean be?&lt;/p&gt;&#xA;" OwnerUserId="2419" LastActivityDate="2015-06-25T05:04:37.117" Title="How deep would the nitrogen and oxygen ocean be if cooled to liquid?" Tags="|atmosphere|ocean|flooding|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5058" PostTypeId="2" ParentId="5055" CreationDate="2015-06-24T17:00:35.060" Score="5" Body="&lt;p&gt;I'm not sure it would be entirely liquefiable as the atmosphere gets thinner and thinner, but if we ignore that, then it's a simple matter of calculating density and ocean cover.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;78% Nitrogen, 0.807 g/mL  Source:  &lt;a href=&quot;https://en.wikipedia.org/wiki/Liquid_nitrogen&quot; rel=&quot;nofollow&quot;&gt;Liquid Nitrogen&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;21% Oxygen, 1.141 g/mL  Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Liquid_oxygen&quot; rel=&quot;nofollow&quot;&gt;Liquid Oxygen&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ignoring the 1% of trace gases, average density of liquefied air, 0.87 g/mL, or 87% the density of water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mass of air, 1 ATM is equivalent to 33.9 feet of water.   Source:  &lt;a href=&quot;http://www.kylesconverter.com/pressure/atmospheres-to-feet-of-water&quot; rel=&quot;nofollow&quot;&gt;link&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and the Earth is 71% covered by oceans.   From there it's just math.  33.9*(1/.87)*(1/.71) = 54.88 feet.    That's quite a bit less than the oceans would rise by freezing solid (which might not happen given volcanism and warmth coming from the earth, but if even half of the average depth of 14,000 feet of oceans froze, a 9% increase in volume, we'd be looking at some 600 feet of sea level rise by freezing.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Colder temperatures might cause the liquid nitrogen/oxygen to contract a bit further but that's a ballpark answer - 54 feet, 10 1/2 inches.   Some of the air might dissolve into the oceans prior to the oceans turning to ice, cause colder water can hold more gas, so the actual answer might be a little bit less than that.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2470" LastEditDate="2015-06-25T01:59:02.537" LastActivityDate="2015-06-25T01:59:02.537" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5059" PostTypeId="2" ParentId="5052" CreationDate="2015-06-24T17:45:33.720" Score="2" Body="&lt;p&gt;Referring to a research article &lt;em&gt;&quot;The Role of Temperature and Humidity on Seasonal Influenza in Tropical Areas: Guatemala, El Salvador and Panama, 2008–2013&quot;&lt;/em&gt; by Soebiyanto &lt;em&gt;et al&lt;/em&gt;, 2014 &lt;a href=&quot;http://dx.doi.org/10.1371/journal.pone.0100659&quot; rel=&quot;nofollow&quot;&gt;DOI: 10.1371/journal.pone.0100659&lt;/a&gt;, the authors investigate a few regions in tropical wet and dry (savanna) climates in Central America, some of which are lowland. The authors state that Panama and El Salvador study locations have less varied topography and are at lower elevations than Guatemala. They give the following Specific Humidity values and standard deviation i g/kg:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Lowland Panama province in Panama: 17.66 +/- 1.04 g/kg&#xA;Chiriqui province in Panama: 15.38 +/- 1.47 g/kg&#xA;West-central departments in El Salvador: 14.29 +/- 2.14 g/kg&#xA;San Miguel, El Salvador: 14.84 +/- 2.32 g/kg&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;So, a specific humidity in the 10-20 g/kg seems like a reasonable range for seasonally dry and humid lowland tropical regions in Central America.&lt;/p&gt;&#xA;" OwnerUserId="3085" LastEditorUserId="64" LastEditDate="2015-06-24T18:15:46.920" LastActivityDate="2015-06-24T18:15:46.920" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5060" PostTypeId="1" CreationDate="2015-06-24T18:31:17.653" Score="9" ViewCount="328" Body="&lt;p&gt;How are they formed? Why are they so stable? What finally breaks them apart and what is their typical lifespan? Why are fluid particles trapped inside it and advected towards the center? How do they affect transport of particulate matter and heat in the ocean?&lt;/p&gt;&#xA;" OwnerUserId="200" LastActivityDate="2015-06-24T18:31:17.653" Title="What are black-hole ocean eddies?" Tags="|ocean|oceanography|coriolis|eddies|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5061" PostTypeId="2" ParentId="4964" CreationDate="2015-06-24T18:55:01.487" Score="4" Body="&lt;p&gt;I guess that it is possible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As mentioned by others, on top of static stress triggering, which is the effect of an earthquake in its vicinity (typically up to 2-3 rupture lengths away), another way by which an earthquake can trigger others is by dynamic stress triggering, which may have effects farther away but are hard to identify and measure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far, the only earthquake that seems to have demonstrated how dynamic triggering over long distances can take place is the &lt;a href=&quot;http://www.usgs.gov/newsroom/article_pf.asp?ID=3408&quot; rel=&quot;nofollow&quot;&gt;2012 Indian Ocean earthquakes&lt;/a&gt;. This earthquake had an unusual combination of characteristics: it was a very large strike-slip earthquake, it took place in oceanic crust (which allows surface waves to travel longer) and had a very large concentrated burst of Mw 8.4 - 8.5 with large slip over limited distance (I do not post sources since there are at least 3 apparently good studies with &lt;em&gt;very&lt;/em&gt; different results, for example one study says that slip exceeded 80m locally (!)). These characteristics suggest that this earthquake was very efficient at radiating energy through the crust rather than towards the interior or through very fragmented crust.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, what this earthquake showed, is that it is possible to speed up significant earthquakes (earthquakes that were almost ready to happen, but they were sped up up to 90 days). Still, it is only one case, the mechanism is not well understood, we are not sure why this earthquake seemed to have caused this phenomenon while other earthquakes with higher magnitudes did not show the same effects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Concluding, while static stress triggering has only a fairly local effect, dynamic stress triggering may have a wider effect but we only have detected one such case, which could very well have been a coincidence or due to an unusual mechanism. So the answer to your question seems to be yes, but with doubts and in any case for very special earthquakes.&lt;/p&gt;&#xA;" OwnerUserId="2938" LastEditorUserId="2938" LastEditDate="2015-06-25T02:23:19.633" LastActivityDate="2015-06-25T02:23:19.633" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5062" PostTypeId="2" ParentId="5055" CreationDate="2015-06-25T04:53:31.273" Score="3" Body="&lt;p&gt;For the atmosphere to be so cold it turns to liquid, extreme &lt;a href=&quot;http://news.nationalgeographic.com/news/2010/03/100304-snowball-earth-ice-global-warming/&quot; rel=&quot;nofollow&quot;&gt;Snowball Earth&lt;/a&gt; conditions would exist. Any atmospheric gases that would turn into liquids would form a layer on the frozen surface of the Earth, that includes any surface rock that may be exposed and frozen water from oceans, lakes, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Earth&quot; rel=&quot;nofollow&quot;&gt;source&lt;/a&gt;, gives the amount of nitrogen and oxygen in the atmosphere is $78.084\%$ and $20.946\%$ and the total mass of the atmosphere as ${5.148} 10^{18} kg$ respectively. From this, &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mass of nitrogen in the atmosphere is $4.0198$ x $10^{18}$ $kg$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mass of oxygen in the atmosphere is $1.0783$ x $10^{18}$ $kg$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The density of &lt;a href=&quot;http://www.aqua-calc.com/page/density-table/substance/Liquid-blank-nitrogen&quot; rel=&quot;nofollow&quot;&gt;liquid nitrogen&lt;/a&gt; is $804$ $kg/m^3$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The density of &lt;a href=&quot;http://www.aqua-calc.com/page/density-table/substance/Liquid-blank-oxygen&quot; rel=&quot;nofollow&quot;&gt;liquid oxygen&lt;/a&gt; is $1140$ $kg/m^3$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Density is mass divided by volume, $\rho$ $=$ $m/v$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using this the volume of liquid gas can be found.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The volume of liquid nitrogen, from the atmosphere would be&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$4.0198$ x $10^{18}$/$804$ $=$ $5$ x $10^{15}$ $m^3$ $=$ $5$ x $10^{6}$ $km^3$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The volume of liquid oxygen, from the atmosphere would be&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$1.0783$ x $10^{18}$/$1140$ $=$ $9.459$ x $10^{14}$ $m^3$ $=$ $9.459$ x $10^{5}$ $km^3$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These liquids would lie of the surface of the frozen Earth. The &lt;a href=&quot;http://chartsbin.com/view/wwu&quot; rel=&quot;nofollow&quot;&gt;surface area of the Earth&lt;/a&gt; is $510,072,000$ $km^2$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, the height above the surface of the Earth that liquid oxygen would rise to is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$9.459$ x $10^5$ / $510,072,000$ $=$ $0.001854$ $km$ $=$ $1.854$ $m$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and the height to which liquid nitrogen would rise, would be,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$5$ x $10^6$ / $510,072,000$ $=$ $0.009803$ $km$ $=$ $9.803$ $m$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because liquid oxygen would form first due to its higher boiling point, the combined height due to both nitrogen and oxygen becoming liquids would be&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$1.85$ + $9.80$ = $11.65$ m&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2015-06-25T05:04:37.117" LastActivityDate="2015-06-25T05:04:37.117" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5063" PostTypeId="1" CreationDate="2015-06-25T06:51:35.720" Score="15" ViewCount="2402" Body="&lt;p&gt;I understand the mathematics behind it but I am looking for an intuitive description.&lt;/p&gt;&#xA;" OwnerUserId="3087" LastActivityDate="2017-09-28T12:34:57.427" Title="At the ocean surface, why do large amplitude waves travel faster than small amplitude waves?" Tags="|ocean|oceanography|waves|wave-modeling|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="5064" PostTypeId="1" AcceptedAnswerId="5089" CreationDate="2015-06-25T08:54:38.427" Score="7" ViewCount="2137" Body="&lt;p&gt;What is the meaning of seismic spectral blueing? Please cite any good introductory materials if possible.&lt;/p&gt;&#xA;" OwnerUserId="2662" LastEditorUserId="28050" LastEditDate="2015-06-25T14:37:34.393" LastActivityDate="2015-06-30T01:09:49.020" Title="What is the meaning of seismic spectral blueing?" Tags="|geophysics|seismology|waves|wave-modeling|seismic|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5067" PostTypeId="2" ParentId="3088" CreationDate="2015-06-25T15:45:44.493" Score="4" Body="&lt;p&gt;The notion that an integral is the area under a curve, and that differentiation is the slope doesn't really provide a lot of physical insight for seismograms. Such signals are oscillatory, meaning that the curve moves above and below (the peaks and troughs) a mean value of zero; summing up these areas (integration) will give you zero.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, what we see on a sample by sample basis is that &lt;a href=&quot;http://www.agilegeoscience.com/blog/2011/12/28/i-is-for-integrated-trace.html&quot; rel=&quot;nofollow&quot;&gt;summation&lt;/a&gt; (integration) and differencing (differentiation) both look like 90 degree phase rotations of the original signal; but in opposite directions. Just as the derivative of sine is cosine, and a sine-wave shifted by 90 degrees is also a cosine; calculus on periodic signals changes the phase of the signal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, the &lt;a href=&quot;http://www.reproducibility.org/rsflog/index.php?/archives/274-Program-of-the-month-sfenvelope.html&quot; rel=&quot;nofollow&quot;&gt;signal envelope&lt;/a&gt;, which is a positively valued function, might be a better description of the amplitude intensity versus time. Here is an illustration of &lt;a href=&quot;http://www.agilegeoscience.com/blog/2011/3/23/e-is-for-envelope.html&quot; rel=&quot;nofollow&quot;&gt;signal envelopes&lt;/a&gt; on seismic traces.&lt;/p&gt;&#xA;" OwnerUserId="2924" LastActivityDate="2015-06-25T15:45:44.493" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5068" PostTypeId="1" AcceptedAnswerId="5085" CreationDate="2015-06-25T17:40:49.537" Score="3" ViewCount="161" Body="&lt;p&gt;I suspect it has to do with the difference in size of a rain drop and that of the water particles in the cloud.&lt;/p&gt;&#xA;" OwnerUserId="3087" LastActivityDate="2015-06-29T10:13:46.463" Title="Why do clouds have areas of darkness instead of scattering light to produce a rainbow?" Tags="|meteorology|atmosphere|clouds|rainfall|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5069" PostTypeId="2" ParentId="5068" CreationDate="2015-06-26T01:34:45.813" Score="-1" Body="&lt;p&gt;Not an expert but I believe it has something to do with water vapor vs water droplets.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you were in elementary school and used a prism to produce a color spectrum the prism was a clear solid, somewhat like a water drop is a clear liquid. Reflectivity occurred with that mass and produced a color spectrum. When this occurs within rain it is called a RAINBOW!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Next question?&lt;/p&gt;&#xA;" OwnerUserId="3090" LastActivityDate="2015-06-26T01:34:45.813" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5071" PostTypeId="1" CreationDate="2015-06-26T01:50:55.320" Score="9" ViewCount="1788" Body="&lt;p&gt;A while ago I created a spreadsheet to calculate evaporation loss. I found several formulas to do that, two from Kevin Rafferty and one from Engineering Toolbox. The one from Engineering Toolbox was too convoluted, and I couldn't figure out how to write it in Excel. The ones from Rafferty were fairly straightforward, but the two he published were different and yield different results. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first is from Kevin Rafferty, P.E., Pond Heat Loss, 1986:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ W_p=\frac{(1 + 0.225v)/0.018}{85.74 \times (T_s+460)} \times (P_w-P_a) \times 144 \times A $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where:  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$W_p$ = Rate of evaporation in lbm/h  &lt;/li&gt;&#xA;&lt;li&gt;$A$ = Pond surface area in ft$^2$&lt;/li&gt;&#xA;&lt;li&gt;$v$ = Air velocity in ft/sec&lt;/li&gt;&#xA;&lt;li&gt;$P_w$ = Saturation vapor pressure of pond water in psia&lt;/li&gt;&#xA;&lt;li&gt;$P_a$ = Saturation pressure air dew point in psia&lt;/li&gt;&#xA;&lt;li&gt;$T_s$ = Surface temperature °F&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The other is from Kevin Rafferty, P.E., Tonya Boyd, Aquaculture Information Package, 1998:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ W_p=(0.097+0.38v) \times (P_w-P_a) \times A $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$W_p$ = Rate of evaporation (lbm/h)&lt;/li&gt;&#xA;&lt;li&gt;$A$ = Pond surface area (ft$^2$)&lt;/li&gt;&#xA;&lt;li&gt;$v$ = Air velocity (mph)&lt;/li&gt;&#xA;&lt;li&gt;$P_w$ = Saturation vapor pressure of pond water (psia)&lt;/li&gt;&#xA;&lt;li&gt;$P_a$ = Saturation pressure at the air dew point (psia)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;$P_w$ is calculated by the formula&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ P_w = 6.11 \times 10^\left({7.5T_s}/{237.3 + T_s)}\right) $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$P_a$ is calculated by the same formula except that the dew point temperature in °F is used in place of $T_s$, so the pond surface temperature is used in both main formulas, except that in the second formula it is used to calculate the pond saturation vapor pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.dropbox.com/s/e9j4vno60wl6e70/Evaporation%20Loss.xlsx?dl=0&quot; rel=&quot;nofollow&quot;&gt;The spreadsheet file can be found here.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone have any idea which is the more accurate?  &lt;/p&gt;&#xA;" OwnerUserId="2959" LastEditorUserId="28050" LastEditDate="2015-10-29T16:21:02.197" LastActivityDate="2015-10-31T04:26:53.653" Title="Evaporation loss formulas" Tags="|meteorology|hydrology|water-vapour|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5072" PostTypeId="1" AcceptedAnswerId="5078" CreationDate="2015-06-26T13:33:24.850" Score="13" ViewCount="1297" Body="&lt;p&gt;Where can I download GIS data delimiting global climate types?  For example mediterannean climate, temperate climate, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, how similar are temperature profiles for various places in the same climate classification?&lt;/p&gt;&#xA;" OwnerUserId="3095" LastEditorUserId="543" LastEditDate="2015-06-28T02:31:45.663" LastActivityDate="2015-06-29T04:26:38.817" Title="GIS Data on climate types" Tags="|climate|temperature|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5073" PostTypeId="1" AcceptedAnswerId="5074" CreationDate="2015-06-26T18:02:50.463" Score="7" ViewCount="543" Body="&lt;p&gt;I am curious about current technology but I am particularly interested in what techniques were employed prior to the advent of satellite technology.&lt;/p&gt;&#xA;" OwnerUserId="3087" LastActivityDate="2015-06-26T21:31:42.393" Title="How is/was continental drift monitored?" Tags="|geology|plate-tectonics|tectonics|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5074" PostTypeId="2" ParentId="5073" CreationDate="2015-06-26T20:36:11.950" Score="9" Body="&lt;p&gt;Scientific &lt;a href=&quot;http://www.pocketgpsworld.com/howgpsworks.php&quot;&gt;GPS&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Satellite_laser_ranging&quot;&gt;SLR&lt;/a&gt; have been used for &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2003JB002944/full&quot;&gt;some time&lt;/a&gt; now, and the &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/97JB00514/pdf&quot;&gt;measurements&lt;/a&gt; are rather accurate. Not only do we measure horizontal movements of tectonic plates, but also uplift as e.g. in the Tibetan and Colorado plateaus. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Before the GPS was introduced, &lt;a href=&quot;https://en.wikipedia.org/wiki/Paleomagnetism&quot;&gt;paleomagnetism&lt;/a&gt; were used in some studies to estimate the velocities; The age of oceanic crust are estimated by various methods and the travel distance is estimated from the width of the magnetic polarized bands in the ocean floor. To understand &lt;a href=&quot;http://www.scotese.com/earth.htm&quot;&gt;paleogeography&lt;/a&gt; and make good models we need to incorporate all branches of geology. E.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Biostratigraphy&quot;&gt;fossil records&lt;/a&gt;, paleomagnetism, &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiometric_dating&quot;&gt;radiometric age estimation&lt;/a&gt; of rocks. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some active faults (E.g. San Andreas) can also be directly measured with laser ranging or, in some cases, with a measurement tape to measure deformation of trenches or railway tracks. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Still, scientists are trying to understand the exact driving forces behind plate tectonics. &lt;a href=&quot;http://www.earthbyte.org/Resources/Pdf/Ghosh-Holt-2012-Science-PlateMotionsStressesGlobalDynamicModels.pdf&quot;&gt;Modelling&lt;/a&gt; of &lt;a href=&quot;https://en.wikipedia.org/wiki/Mantle_convection&quot;&gt;mantel dynamics&lt;/a&gt; is an interesting field of research and many questions remains. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2015-06-26T21:31:42.393" LastActivityDate="2015-06-26T21:31:42.393" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5075" PostTypeId="2" ParentId="4881" CreationDate="2015-06-27T05:21:25.123" Score="6" Body="&lt;p&gt;These are basalts with columnar joints. Basalt is an igneous rock that forms when magma (liquid + crystals) erupts onto the surface as a lava flow or gets injected into cooler shallow crust and forms an intrusive dike or sill.  Because basalt cools quickly, basalt commonly contains glass as well as crystals. The physical properties of magma changes rapidly as it cools through the liquid-glass transition temperature. When a magma cools through the liquid-glass transition temperature, its specific volume decreases and its viscosity increases rapidly. The volume of the lava flow decreases (it shrinks) and it become more viscous and brittle. This creates stresses in the lava flow that eventually causes it to fracture. Columnar joints are fractures that have formed because the stress has exceeded the brittle strength of the rock.&lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2015-06-27T05:21:25.123" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5076" PostTypeId="1" AcceptedAnswerId="5077" CreationDate="2015-06-27T17:39:11.023" Score="9" ViewCount="28340" Body="&lt;p&gt;I know there is this question already &lt;a href=&quot;https://earthscience.stackexchange.com/questions/5050/how-do-i-convert-relative-humidity-into-specific-humidity&quot;&gt;How do I convert Relative Humidity into specific humidity&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;but I don't have ρws = density of water vapor (kg/m3) and ρ = density of the moist or humid air (kg/m3).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there another way to calculate it? Also I have air pressure but it's in the range of 95000-96000.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have used the &lt;a href=&quot;https://github.com/PecanProject/pecan/blob/master/modules/data.atmosphere/R/metutils.R&quot; rel=&quot;nofollow noreferrer&quot;&gt;rh2qair&lt;/a&gt; function from the &lt;a href=&quot;https://github.com/PecanProject/pecan/tree/master/modules/data.atmosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;PEcAn data.atmosphere R package&lt;/a&gt; but I get values such as 1.5463 converts relative humidity to specific humidity&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;    @title RH to SH &#xA;    @param rh relative humidity (proportion, not %) &#xA;    @param T absolute temperature (Kelvin) &#xA;    @export &#xA;    @author Mike Dietze @aliases rh2rv &#xA;    rh2qair &amp;lt;- function(rh, T) {   &#xA;        qair &amp;lt;- rh * 2.541e6 * exp(-5415.0 / T) * 18/29   &#xA;        return(qair) &#xA;    }&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="3061" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-07-02T19:32:28.727" Title="How to calculate specific humidity with relative humidity, temperature, and pressure" Tags="|meteorology|atmosphere|humidity|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5077" PostTypeId="2" ParentId="5076" CreationDate="2015-06-28T01:09:41.170" Score="7" Body="&lt;p&gt;It looks like your program is using an approximation based on&#xA;$q \approx w = w_s*RH$ with an approximation of Clausius-Clapeyron to find $w_s$.  Looking at a few values of RH,T and P, your approximation is pretty close (+/- 5%) to an analytic answer.  Based on the output you quoted it looks like you are providing incorrect values of RH.  Note in the comments to your routine it says:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;@param rh relative humidity (proportion, not %) &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;This means you need to provide the RH proportion, not the percentage.  E.g. divide by 100 -- RH=1 for 100%, RH=0.5 for 50%, etc.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you adjust your input data you should be able to use your code as-is.  If you wish to compare it to something, you can reference the solution below.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;If you are given $RH$ (in the range [0,1]), $T$ (K) and $p$ (Pa) you can proceed as follows.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Knowing that $$RH = \dfrac{e}{e_s},$$ $$w = \dfrac{e\ R_d}{R_v(p-e)},$$ and $$q = \dfrac{w}{w+1}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then we can solve for specific humidity $q$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rather than combining this into a single formula and solving, it is more straightforward to present this incrementally.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, find $e_s(T)$ where $$e_s(T) = e_{s0}\exp\left[\left(\dfrac{L_v(T)}{R_v}\right)\left(\dfrac{1}{T_0}-\dfrac{1}{T}\right)\right]$$ and then find $e$ from the first formula ($e = RH*e_s$).  Then plug $e$ into the formula for $w$ and then that result into the formula for $q$. &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Variables used:&lt;br&gt;&#xA;&lt;sub&gt;&#xA;$q$ specific humidity or the mass mixing ratio of water vapor to total air (dimensionless)&lt;br&gt;&#xA;$w$ mass mixing ratio of water vapor to dry air (dimensionless)&lt;br&gt;&#xA;$e_s(T)$ saturation vapor pressure (Pa)&lt;br&gt;&#xA;$e_{s0}$ saturation vapor pressure at $T_0$ (Pa)&lt;br&gt;&#xA;$R_d$ specific gas constant for dry air (J kg$^{-1}$ K$^{-1}$)&lt;br&gt;&#xA;$R_v$ specific gas constant for water vapor (J kg$^{-1}$ K$^{-1}$)&lt;br&gt;&#xA;$p$ pressure (Pa)&lt;br&gt;&#xA;$L_v(T)$ specific enthalpy of vaporization (J kg$^{-1}$)&lt;br&gt;&#xA;$T$ temperature (K)&lt;br&gt;&#xA;$T_0$ reference temperature (typically 273.16 K) (K)&lt;br&gt;&#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2015-06-28T01:55:15.570" LastActivityDate="2015-06-28T01:55:15.570" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5078" PostTypeId="2" ParentId="5072" CreationDate="2015-06-28T02:28:07.153" Score="10" Body="&lt;p&gt;NOAA has climate division files in netcdf and shapefile format, though they may be just CONUS:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/usclimdivs/boundaries.html&quot;&gt;http://www.esrl.noaa.gov/psd/data/usclimdivs/boundaries.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most promising link looks like this source with paper citation below.  They have lots of freely available data in a variety of formats:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://koeppen-geiger.vu-wien.ac.at/shifts.htm&quot;&gt;http://koeppen-geiger.vu-wien.ac.at/shifts.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rubel, F., and M. Kottek, 2010: Observed and projected climate shifts 1901-2100 depicted by world maps of the Köppen-Geiger climate classification. Meteorol. Z., 19, 135-141. DOI: 10.1127/0941-2948/2010/0430.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's also the ArcGIS Online map service that has Koppen-Geiger Observed and Predicted Climate Shifts:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.arcgis.com/home/item.html?id=0b9f1f90f4f745daacbc35599609b59a&quot;&gt;http://www.arcgis.com/home/item.html?id=0b9f1f90f4f745daacbc35599609b59a&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer your question about the types of temperature in a classification,  I suggest you refer to the paper above and the ranges of expected temperatures for each Koppen climate type which can be found here: &lt;a href=&quot;https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification&quot;&gt;https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For modeled and observed temperature, precipitation, etc. you might find the following resources helpful:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://iridl.ldeo.columbia.edu/&quot;&gt;http://iridl.ldeo.columbia.edu/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://gisclimatechange.ucar.edu/&quot;&gt;http://gisclimatechange.ucar.edu/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.worldclim.org/&quot;&gt;http://www.worldclim.org/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2015-06-28T17:52:03.020" LastActivityDate="2015-06-28T17:52:03.020" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5079" PostTypeId="1" AcceptedAnswerId="5080" CreationDate="2015-06-28T06:40:22.553" Score="1" ViewCount="954" Body="&lt;p&gt;What is the natural replenishment rate of oil? Are extinction events connected with higher production?&lt;/p&gt;&#xA;" OwnerUserId="3087" LastActivityDate="2015-06-28T10:34:31.057" Title="What is the natural replenishment rate of oil?" Tags="|geology|petrology|mass-extinction|" AnswerCount="1" CommentCount="0" ClosedDate="2015-06-29T02:49:32.623" ContentLicense="CC BY-SA 3.0" />
  <row Id="5080" PostTypeId="2" ParentId="5079" CreationDate="2015-06-28T10:34:31.057" Score="2" Body="&lt;p&gt;Almost nil on human time scales.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The total estimated reserves (this number keeps changing over time) are of the order of 300E9 m^3. For convenience lets say all of this oil formed over the last 300 million years at a constant rate. Then the rate of formation is  1000 m^3 per year or ~6000 barrels of usable oil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This obviously is a simple back of the envelope calculation and doesn't account for oil that has been lost/degraded/converted to other hydrocarbons over time. Also the rate of formation varies a lot (depends on climate, position/structure of plates and what not).&lt;/p&gt;&#xA;" OwnerUserId="1275" LastActivityDate="2015-06-28T10:34:31.057" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5081" PostTypeId="2" ParentId="3088" CreationDate="2015-06-28T21:29:36.463" Score="2" Body="&lt;p&gt;Most seismometers measure velocity of ground motion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you integrate velocity you get displacement.  So, integrating tells you the displacement of the ground relative to its original position.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you differentiate velocity you get acceleration.  So, differentiating tells you how much the ground is accelerating at any given moment.&lt;/p&gt;&#xA;" OwnerUserId="40" LastActivityDate="2015-06-28T21:29:36.463" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5082" PostTypeId="1" CreationDate="2015-06-29T04:17:11.787" Score="8" ViewCount="615" Body="&lt;p&gt;I have historical precipitation data for hundreds of cities around the world. I would like to algorithmically determine when the rainy season (if exists) is for each location. Are there any algorithms out there that can determine this based on the monthly averages alone?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some problems that I envision are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Having a lot of rain is not enough. Many places in south east asia have very heavy rain falls for a couple of minutes a day, but it still is not necessarily considered rainy season.&lt;/li&gt;&#xA;&lt;li&gt;Is it better to say that if the weather is x standard deviations above the average precipitation that it is rainy season or use a moving average?&lt;/li&gt;&#xA;&lt;li&gt;Any other ideas, links, etc?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I'm brand new to the field so help and an open discussion would be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="3101" LastActivityDate="2019-05-10T01:27:57.777" Title="Algorithmically Determining the Rainy Season" Tags="|meteorology|weather-forecasting|rainfall|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5083" PostTypeId="2" ParentId="5072" CreationDate="2015-06-29T04:26:38.817" Score="2" Body="&lt;p&gt;Also look at:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Peel, M. C., Finlayson, B. L. and McMahon, T. A. (2007) Updated world map of the Köppen-Geiger climate classification. Hydrol. Earth Syst. Sci. 11, 1633-1644. DOI: 10.5194/hess-11-1633-2007.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The GIS coverage is included in the supplemental materials.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2015-06-29T04:26:38.817" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5084" PostTypeId="2" ParentId="5082" CreationDate="2015-06-29T09:40:19.143" Score="4" Body="&lt;p&gt;Maybe you can try Fourier Analysis - &lt;a href=&quot;https://en.wikipedia.org/wiki/Fourier_analysis&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Fourier_analysis&lt;/a&gt; to distinguish certain patterns. There are papers on using this method to identify rainfall and pollution periodicity. For example, weekend effect on urban pollution. I can't think of any papers right now, but I am sure you can find something.&lt;/p&gt;&#xA;" OwnerUserId="964" LastEditorUserId="6" LastEditDate="2015-06-29T13:01:28.350" LastActivityDate="2015-06-29T13:01:28.350" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5085" PostTypeId="2" ParentId="5068" CreationDate="2015-06-29T10:13:46.463" Score="2" Body="&lt;p&gt;It really depends on the cloud. Actually, it depends on its density and thickness which is related to concentrations and type of hydro-meteors in it, the size distribution of water droplets and ice crystals, and shape of ice crystals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rainbows are formed by the refraction and internal reflection of light in water drops (usually rain).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But cirrostratus clouds can form a halo by refraction on ice crystals in shape of hexagonal prisms. These halos have angular radius of about 22 degrees.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another optical phenomena that you might find interesting is a corona around the Sun or the Moon which is caused by diffraction of light on water droplets and tiny ice crystals. Angular size of a corona depends on the size of water droplets.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;'Areas of darkness' are due to the density and optical thickness of a cloud. More ice crystals and water droplets cause more scattering which results in less light reaching your eyes making a cloud appear darker.&lt;/p&gt;&#xA;" OwnerUserId="964" LastActivityDate="2015-06-29T10:13:46.463" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5086" PostTypeId="2" ParentId="5082" CreationDate="2015-06-29T12:47:52.540" Score="5" Body="&lt;p&gt;This is an interesting statistics problem.  I would do this for starters.  Take all the years of data and calculate average rainfall amounts for each day of the year.  If you're looking for the rainy &lt;em&gt;season&lt;/em&gt;, I would use maybe a 30-day moving average on this, but make sure that the average can wrap around Jan 1.  Once you have these values -- 365 values for each site -- I suggest trying a few things:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Try out the standard deviation approach.  It's easy to calculate, so you should be able to play around with the particular number &quot;x&quot; in &quot;x standard deviations above the mean&quot;.  If it works for you, there's no reason to make it harder.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Using &quot;x standard deviations above the mean&quot; really just means that you're looking for a certain value of the cumulative distribution function (CDF) of rainfall.  Instead of using standard deviation, you could calculate these CDFs for each site from those 365 values, and pick the 75th percentile or something.  I'm still thinking through whether this would guarantee that you get a &quot;season&quot;; it's possible that the top-percentile values of the year are nowhere near each other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) Plot out a few distributions for key sites: dry midlatitudes, wet midlatitudes, polar, tropics (monsoon-dominated).  If these PDFs look pretty similar, you might be able to figure out a sensible approach.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think the key difficulty here isn't going to be that different places have different total rainfall, but that different places can have rainy seasons of different &lt;em&gt;lengths&lt;/em&gt;.  If the season was always 30 days, I think this approach would be fine.  I'm really interested in seeing those CDFs just to see how different they are.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let us know what you come up with!&lt;/p&gt;&#xA;" OwnerUserId="1342" LastActivityDate="2015-06-29T12:47:52.540" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5087" PostTypeId="1" AcceptedAnswerId="5098" CreationDate="2015-06-29T13:21:04.953" Score="11" ViewCount="490" Body="&lt;p&gt;Many of the predictions of Global Warming models are dated in the range of ~100 years or more from the present. I'm wondering if any models or data provide predictions for the more immediate future, say $10$ - $20$ years from today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Specifically, I'd like to hear about predictions that directly influence humans, such as weather, flooding, disease, etc.&lt;/p&gt;&#xA;" OwnerUserId="614" LastActivityDate="2015-07-02T10:05:53.050" Title="What are some near term effects of Global Warming?" Tags="|climate-change|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="5088" PostTypeId="2" ParentId="5010" CreationDate="2015-06-29T16:51:07.893" Score="3" Body="&lt;p&gt;I think the size of the continent is a big contributor.  If there's very little cloud cover, and little rain, the air just keeps drying out the ground.  Try finding a good map of surface or lower-level winds, and just compare how long it takes an air parcel to go from over ocean to the Sahara.  Sometimes the winds will come straight from the oceans, but often they come from over land: the Near East and Asia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But yes, all your examples end at mountain ranges.  Or rather, start there.  At the horse latitudes and on the equator-ward edges of the subtropical ridges, winds mostly blow east to west, not west to east.  A number of these deserts are thus in rain shadows of a sort (&lt;a href=&quot;https://en.wikipedia.org/wiki/Rain_shadow&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Rain_shadow&lt;/a&gt;).  This kinda ties in with the above: Since the wind blows east to west, the air that blows over the Sahara hasn't just been over Africa but also much of Asia, drying out along the way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My explanation for Australia would be this.  It doesn't have major mountain chains, so it's not in a rain shadow.  But it doesn't have mountains, so there's nothing to initiate orographic precipitation.  It's convective precipitation or nothing, once you get inland.  And since the ground is dry, convective precipitation doesn't have much of a water source, so it doesn't rain much and the ground stays dry.  Someone with more background on Australia should chime in on that, though.&lt;/p&gt;&#xA;" OwnerUserId="1342" LastActivityDate="2015-06-29T16:51:07.893" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5089" PostTypeId="2" ParentId="5064" CreationDate="2015-06-30T00:52:26.037" Score="5" Body="&lt;p&gt;&lt;strong&gt;It is a kind of spectral shaping, intended to increase the vertical resolution of seismic reflection data.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The logic goes like this:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Seismic data is &lt;a href=&quot;https://en.wikipedia.org/wiki/Bandlimiting&quot; rel=&quot;nofollow&quot;&gt;band-limited&lt;/a&gt; and lacks high frequencies. This limits its vertical (travel time, and thus thickness) resolution. This is annoying because we often care about thin beds. &lt;/li&gt;&#xA;&lt;li&gt;The spectral peak of seismic data tends to be at a fairly low frequency compared to its total band. That is, the longer wavelengths are disproportionately strong compared to the short ones. Thinking of an analogy with the electromagnetic spectrum, we could say that the spectrum is reddish. &lt;/li&gt;&#xA;&lt;li&gt;We assume that geology is whitish, or scale free, so all 'frequencies' are represented (when we're in the time domain, they are frequencies; when in depth they are &lt;a href=&quot;http://www.agilegeoscience.com/blog/2012/5/1/k-is-for-wavenumber.html&quot; rel=&quot;nofollow&quot;&gt;wavenumbers&lt;/a&gt;). &lt;/li&gt;&#xA;&lt;li&gt;So maybe we can reshape the seismic spectrum to more closely match the geological spectrum, as derived from logs, by boosting the higher seismic frequencies a bit.&lt;/li&gt;&#xA;&lt;li&gt;One way to do this is to design an operator, a sort of wavelet, with which to convolve the seismic data. The result would be the seismic with the boosted frequencies. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.spgindia.org/2010/367.pdf&quot; rel=&quot;nofollow&quot;&gt;Here's one example of the application of the method&lt;/a&gt; [PDF] from Yadav et al. (2010).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's just my opinion, but I'd treat the idea and the method with the same skepticism as any method claiming to enhance seismic resolution. That said, I'm sure there's a champion of blueing for every detractor. &lt;em&gt;Caveat interpretor.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2015-06-30T01:09:49.020" LastActivityDate="2015-06-30T01:09:49.020" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5090" PostTypeId="2" ParentId="4531" CreationDate="2015-06-30T03:21:00.140" Score="4" Body="&lt;p&gt;VTI anisotropy can also result from stress induced anisotropy when the two horizontal stresses are equal and the overburden is the largest stress acting on a stress sensitive formation such as a weakly consolidated sandstone. In such situations grain contacts are aligned in the vertical direction resulting in a stiffer (faster compressional velocity) response. See e.g. Detection of stress-induced velocity anisotropy in unconsolidated sands, Vega. The Leading Edge 2006. Note that the anisotropy values provided in Thomsen 1986 are not necessarily reliable and predate modern laboratory measurements. More recent measurements of anisotropy are available from a number of studies such as Wang, 2002 (Part II Geophysics).  A more recent compilation of published mudrock anisotropy parameters is available which shows that very few of the mudrock Thomsen epsilon anisotropy values are negative, see &lt;a href=&quot;http://www.rockphysicists.org/data&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.rockphysicists.org/data&lt;/a&gt;   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/tOVvT.jpg&quot; alt=&quot;From Horne, 2013. Fig. 4 showing a distribution of Thomsen&amp;#39;s epsilon values for 1024 samples&quot;&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other issue is that you do not measure Thomsen's epsilon with a sonic log in a single well. The Thomsen epsilons in your log suite will have been estimated from some other supplementary information, most likely an empirical relation based on observed core measurements.  There is a model developed by Schlumberger referred to as the Modified Annie model that may have been used.  &lt;/p&gt;&#xA;" OwnerUserId="3103" LastEditorUserId="3103" LastEditDate="2015-06-30T06:10:23.950" LastActivityDate="2015-06-30T06:10:23.950" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5093" PostTypeId="1" AcceptedAnswerId="5113" CreationDate="2015-06-30T15:53:23.257" Score="6" ViewCount="100" Body="&lt;p&gt;&quot;Maars usually form when magma rises within a fissure and interacts with groundwater. If groundwater ceases to interact with magma at times during the eruption, continued magma ascent to the surface gives rise to a wide range of volcanic forms and products associated closely with maar-diatreme volcanoes.&quot; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Currently I am trying to compare maars on Earth to maars of Mars. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;How would the gravity of Mars affect the crater formation from the explosion that formed the crater on Mars?&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Database of maars crater on Earth show that maars are typically not circular some are very eccentric. Current hypothesis says is because rather than one explosion forming the crater a multitude of continuous explosions formed the crater also needed to form the bigger craters such as the devil mountain lake in Alaska the largest in the world. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My guess is less gravity means that we need less energy to create a crater as big as the ones on Earth. There is evidence of water on mars. There are millions of crater on mars. There is some evidence for volcanic activity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To put it simply, the explosion is essentially caused by a quick transfer of heat between magma and water. Analogous to throwing water droplets to a pot with hot oil in the stove, it starts splattering all around. (Don't try this at home) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A human tries this experiment on Mars. Same quantity of oil, same heat source and temperature. The only difference is gravity. if on Earth it generated X amount of joules of energy. Will Human on mars get X + some other amount or X - some other amount simply because of &lt;strong&gt;Gravitational Difference&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="1034" LastActivityDate="2015-07-04T01:36:41.263" Title="Mars maar craters explosive style formation gravitational effect" Tags="|geophysics|geology|geochemistry|planetary-science|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5095" PostTypeId="2" ParentId="4921" CreationDate="2015-07-01T01:28:58.757" Score="3" Body="&lt;p&gt;You may want to investigate the Delivery package available from &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www-old.dpr.csiro.au/StochasticSeismicInversion/&quot; rel=&quot;nofollow&quot;&gt;http://www-old.dpr.csiro.au/StochasticSeismicInversion/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;'Delivery is an open-source, trace-based Bayesian seismic inversion code for use in oil reservoir characterisation at the early development and appraisal stage. See the Computers and Geosciences paper for most of the details, and the Delivery4D preliminary writeup for the time-lapse modelling.'&lt;/p&gt;&#xA;" OwnerUserId="3104" LastActivityDate="2015-07-01T01:28:58.757" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5096" PostTypeId="2" ParentId="4889" CreationDate="2015-07-01T01:31:01.377" Score="3" Body="&lt;p&gt;There is a good discussion of the anisotropy issue by Hornby, Howie and Ince, 2003, Anisotropy correction for deviated-well sonic logs: Application to seismic well tie, Geophysics, 68(2):464-471, &lt;a href=&quot;http://library.seg.org/doi/abs/10.1190/1.1567212&quot; rel=&quot;nofollow&quot;&gt;doi 10.1190/1.1567212&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have an estimate of the anisotropy parameters it is possible to correct your sonic logs for the anisotropic effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that well ties can also suffer as a refer of sonic drift arising from the frequency dependence of wave propagation at sonic frequencies (kHz) and seismic frequencies (Hz).&lt;/p&gt;&#xA;" OwnerUserId="3104" LastEditorUserId="28050" LastEditDate="2015-07-01T15:32:49.170" LastActivityDate="2015-07-01T15:32:49.170" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5097" PostTypeId="2" ParentId="5087" CreationDate="2015-07-01T08:35:46.747" Score="2" Body="&lt;p&gt;Climate predictions are only valid statistically, over long periods - typically &gt;30 years. For shorter periods, any effect of climate change is lost in the random (and cyclic) variations of weather.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This means that climate predictions are never of the form &quot;in the year 2045 we will see x happening&quot; - specific events like that are weather. What can be predicted is &quot;The period from 2050-2080 is likely to be different to the period from 2020-2050 in the following ways...&quot;, looking at differences in statistical measures (such as averages) over long periods.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So you will never see climate science tell you what will happen in specific near-future years. However, it may be possible to predict what general characteristics are likely to be different in the next 10-20 years compared to recent history. The shorter the time period for which the prediction is given, the less certainty there will be in the effects. This doesn't quite answer your question, but hopefully helps to put other answers into context.&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2015-07-02T10:03:52.947" LastActivityDate="2015-07-02T10:03:52.947" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="5098" PostTypeId="2" ParentId="5087" CreationDate="2015-07-02T00:11:51.873" Score="7" Body="&lt;p&gt;The &lt;a href=&quot;https://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter11_FINAL.pdf&quot; rel=&quot;nofollow&quot;&gt;IPCC AR5 chapter 11&lt;/a&gt; covers near-term climate change. I recommend reading the executive summary (it's only 6 pages). My summary of the summary is that near-term climate change is like long-term climate change, but scaled down and with less certainty. Surface air temperatures and upper-ocean temperatures are likely to increase, with an associated increase in atmospheric water vapor. Precipitation is likely to increase where it's already high and likely to decrease where it's already low. Summer Arctic sea ice extent is likely to decrease as well. But there is something there that I want to highlight.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The end of the executive summary talks about near-term air quality, and the beginning talks about predictability. Specifically, it mentions that emissions of chemicals that produce aerosols -- atmospheric particles that interact with solar radiation -- have a wide range of uncertainty, even in the near term. Unlike CO2, aerosols can induce a significant climate response (or at least a change in radiation) over the span of weeks and months. A change in energy use or technology, like India and China adopting sulfur control policies, can thus affect climate quickly and dramatically. This is a source of a lot of the uncertainty in near-term projections; over the long-term, CO2 dominates.&lt;/p&gt;&#xA;" OwnerUserId="1342" LastEditorUserId="39" LastEditDate="2015-07-02T10:05:53.050" LastActivityDate="2015-07-02T10:05:53.050" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5099" PostTypeId="1" AcceptedAnswerId="5102" CreationDate="2015-07-02T03:44:00.920" Score="5" ViewCount="7061" Body="&lt;p&gt;Let $t_0$ be the time instant of interest, $t_{-1}$ be some time before $t_0$, and $t_1$ be some instant in time after $t_0$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now there is no confusion with forecast - if the present time is $t_0$, a forecast at $t_1$, for example, uses a model that assimilates observations at $t_0$, and then step forward in time to make the forecast at $t_1$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Suppose now the present time is $t_1$. I'm confused as to what a hindcast at time $t_0$ means. Do we start up the model at $t_1$, then go backward in time to compute the hindcast at $t_0$, or do we start up the model at $t_{-1}$, then run the model forward to get to $t_0$?&lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorUserId="2645" LastEditDate="2015-07-02T03:51:16.657" LastActivityDate="2015-07-02T10:21:26.140" Title="Meaning of Hindcast" Tags="|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5100" PostTypeId="2" ParentId="5087" CreationDate="2015-07-02T05:43:50.220" Score="4" Body="&lt;p&gt;&lt;em&gt;&quot;I'm wondering if any models or data provide predictions for the more immediate future, say 10  - 20  years from today.&quot;&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;&quot;Specifically, I'd like to hear about predictions that directly influence humans, such as weather, flooding, disease, etc.&quot;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically, I take your question to be: &quot;How are people affected by climate change today?&quot; The expectation being that if present trends continue, the effects may intensify in the near-future (10-20 years.) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suggest you consider how people today are affected by extreme weather, because climate change may manifest today primarily by leading to more intense and frequent extreme weather events.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This recent paper in Nature Climate Change, &lt;a href=&quot;http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2657.html&quot; rel=&quot;nofollow&quot;&gt;Attribution of climate extreme events (2015)&lt;/a&gt; proposes that  'snowmaggedon' in February 2010, superstorm Sandy in October 2012 and supertyphoon Haiyan in November 2013, and, in more detail, the Boulder floods of September 2013, may have been influenced by high sea surface temperatures that had a discernible human component. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the popular article &lt;a href=&quot;http://www.washingtonpost.com/news/energy-environment/wp/2015/06/22/study-sees-a-new-normal-for-how-climate-affects-weather-events/&quot; rel=&quot;nofollow&quot;&gt;&quot;Study sees a ‘new normal’ for how climate change is affecting weather extremes&quot;&lt;/a&gt;, an author summarizes some of the major conclusion of that paper. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, although a moderate storm &quot;Sandy&quot; may have occurred regardless of the effects of global warming, computer modeling suggests it is likely that global warming augmented this storm up to a level great enough to flood the New York subway. &lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2015-07-02T05:43:50.220" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5101" PostTypeId="1" CreationDate="2015-07-02T06:19:03.523" Score="7" ViewCount="1298" Body="&lt;p&gt;I notice that in my town sometimes the pollution/haze/smog sticks around on some days but then on others the sky can be completely clear. I don't necessarily see any difference between windy and non windy days so it seems like it is something else at work.&lt;/p&gt;&#xA;" OwnerUserId="3087" LastEditorUserId="5214" LastEditDate="2016-02-11T13:59:02.717" LastActivityDate="2016-02-11T13:59:02.717" Title="What causes smog to clear up on some days?" Tags="|atmosphere|pollution|atmospheric-chemistry|air-pollution|air-quality|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5102" PostTypeId="2" ParentId="5099" CreationDate="2015-07-02T10:21:26.140" Score="7" Body="&lt;p&gt;A hindcast, also known as a historical re-forecast, integrates the model forward in time just like with a forecast, so you'd initialise the model at $t_{-1}$ and run through to $t_1$.  If you have an assimilation system that can make use of observations at $t_0$, then it would use them in the same way that it would with a forecast.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The point of a hindcast is to do the forecast again using something that wasn't available originally.  That new something might be observations (for assimilation or for verification), the assimilation system or the forecast model.  They can be used to calibrate the modelling system or just to check that updates to the modelling system do actually improve the forecast.  They're often used for cases studies of extreme events or situations that are known to be tricky to forecast; after all, why wait for the next 1 in 30 year event to test your new system when you have one in the archive, probably with lots of verification data accumulated over the years.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2015-07-02T10:21:26.140" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5103" PostTypeId="2" ParentId="5101" CreationDate="2015-07-02T11:25:15.140" Score="7" Body="&lt;p&gt;My guess would be a combination of boundary layer, cloud cover, and emissions (though that isn't terribly specific).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Smog is a combination of nitrogen oxides (which cause smog's brown color), ozone, and particulate matter. These in turn form from emissions of hydrocarbons and nitrogen oxides from vehicles and industrial combustion. If those emissions are lower on some days, the smog's going to be better. But that's a boring answer if you don't have a way of tracking your town's emissions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ozone and nitrogen oxides break down and reform in sunlight, driving a number of chemical reactions; this is why smog is &lt;em&gt;usually&lt;/em&gt; more of an issue in the daytime. Cloud cover can reduce these sunlight-driven reactions, which can help with smog. Rain washes out most of the particulates, so even light rain overnight can help with smog.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the emissions are coming from the ground, they're usually trapped within the boundary layer (&lt;a href=&quot;https://en.wikipedia.org/wiki/Planetary_boundary_layer&quot;&gt;https://en.wikipedia.org/wiki/Planetary_boundary_layer&lt;/a&gt;). Air within the boundary layer is fairly well-mixed. If the boundary layer is low, then the concentrations are high and the smog is bad. Boundary layers increase in size throughout the day as the ground heats up and convection mixes higher into the atmosphere, so a number of places (including my hometown of Los Angeles) have their worst smog in the morning. How long the smog sticks around depends on how quickly the boundary layer can grow. This depends on a ton of interesting factors -- there are entire textbooks on the subject (&lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/0521467454&quot;&gt;The Atmospheric Boundary Layer&lt;/a&gt;, &lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/9027727694&quot;&gt;An Introduction to Boundary Layer Meteorology&lt;/a&gt;) -- but start with the Wikipedia article and let us know if you have more questions about it!&lt;/p&gt;&#xA;" OwnerUserId="1342" LastActivityDate="2015-07-02T11:25:15.140" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5104" PostTypeId="1" AcceptedAnswerId="5105" CreationDate="2015-07-02T17:20:02.560" Score="5" ViewCount="104" Body="&lt;p&gt;If I want to (programatically, in a plant growth model) define a growing season as last frost in spring to first frost in fall, how might I determine these dates based on a weather record that contains hourly temperature and humidity? Perhaps temp &amp;lt; 0 and dew point &gt; 0?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A canonical reference would be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="174" LastActivityDate="2015-07-03T02:45:17.110" Title="How can I define frost based on a weather record?" Tags="|meteorology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5105" PostTypeId="2" ParentId="5104" CreationDate="2015-07-03T02:45:17.110" Score="1" Body="&lt;p&gt;The dew point is the temperature at which water condenses from the atmosphere. When the dew point temperature is below the freezing point of water ($0$ $^oC$, $32$ $^oF$) frost forms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most weather data includes dew point temperatures. Search your data for when the dew point is below the freezing point of water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If your data does not you will need to calculate it to find when it is below the freezing point of water. The formulas &lt;a href=&quot;https://en.wikipedia.org/wiki/Dew_point#Frost_point&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt; will help. &lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-07-03T02:45:17.110" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5106" PostTypeId="2" ParentId="4993" CreationDate="2015-07-03T15:40:44.497" Score="5" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Tethys_Ocean&quot; rel=&quot;noreferrer&quot;&gt;Tethys&lt;/a&gt;, which was previously an ocean, became landlocked by the Indian subcontinent to form a massive body of water before the Indian plate collided with the Euarasian to form the Himalayas (about 250-400 Ma).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't see any visuals on the Tethys as a sea (as opposed to when it was an ocean) widely disseminated on the web. Here's an approximate diagram from my memory of a textbook:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/r6t9k.jpg&quot; alt=&quot;Tethys sea, landlocked by Indian and Eurasian plates, 300 Ma&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="3122" LastActivityDate="2015-07-03T15:40:44.497" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5107" PostTypeId="2" ParentId="4993" CreationDate="2015-07-03T17:51:30.040" Score="4" Body="&lt;p&gt;The Taklamakan.  BEHOLD!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm speculating but it sure looks like the dried bed of an old lake or inland sea to me!  It doesn't stretch the imagination to consider methods for filling it with water.  Divergent weather patterns, ice-age, etc.  Plus, before india began piledriving asia it was actually submerged (by the aforementioned Tethys sea) and portions are still below sea level.  A likely candidate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/kjWPg.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="3123" LastActivityDate="2015-07-03T17:51:30.040" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5109" PostTypeId="1" CreationDate="2015-07-03T21:46:56.640" Score="8" ViewCount="1523" Body="&lt;p&gt;Is heat, dissipated from a hot conductor to the surrounding air harmful to the environment? If it were large-scale would it have any negative eco-effect?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is a source of heat, considered harmful to the environment? Or is heat easily exited from our planet?&lt;/p&gt;&#xA;" OwnerUserId="3125" LastEditorUserId="2470" LastEditDate="2015-07-04T01:56:01.223" LastActivityDate="2015-07-17T18:17:33.867" Title="Is pure &quot;heat&quot; harmful to the environment?" Tags="|climate|climate-change|geothermal-heat|environmental-protection|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5110" PostTypeId="2" ParentId="4760" CreationDate="2015-07-03T21:57:22.733" Score="2" Body="&lt;p&gt;First of all, oxygen isotopes are generally given as &lt;sup&gt;16&lt;/sup&gt;O/&lt;sup&gt;18&lt;/sup&gt;O so it is confusing the way the questions is asked from a geochemical perspective.  My students typically get confused about this.  But it is very simple to understand if you keep in mind that &lt;sup&gt;16&lt;/sup&gt;O is lighter than &lt;sup&gt;18&lt;/sup&gt;O.  Evaporation of ocean water preferentially takes &lt;sup&gt;16&lt;/sup&gt;O relative to &lt;sup&gt;18&lt;/sup&gt;O thus decreasing the &lt;sup&gt;16&lt;/sup&gt;O/&lt;sup&gt;18&lt;/sup&gt;O in ocean water (keep in mind we are talking about a ratio here).  During glacial periods, more water is taken out of the oceans and collected in glaciers which have a high &lt;sup&gt;16&lt;/sup&gt;O/&lt;sup&gt;18&lt;/sup&gt;O ratio.  Thus the ocean water during high glacial periods will be low in &lt;sup&gt;16&lt;/sup&gt;O/&lt;sup&gt;18&lt;/sup&gt;O.  Therefore during a period of no glaciation the &lt;sup&gt;16&lt;/sup&gt;O/&lt;sup&gt;18&lt;/sup&gt;O would be higher than today.  Or, in the silly way the questions states &lt;sup&gt;18&lt;/sup&gt;O/&lt;sup&gt;16&lt;/sup&gt;O  would be lower than today&lt;/p&gt;&#xA;" OwnerUserId="3126" LastEditorUserId="111" LastEditDate="2015-07-07T18:29:58.183" LastActivityDate="2015-07-07T18:29:58.183" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5111" PostTypeId="2" ParentId="3163" CreationDate="2015-07-03T22:18:57.113" Score="3" Body="&lt;p&gt;This is a very good question.  I just took a look at Erlund's paper and note that the geochemistry may say some interesting things about the origin of the magma.  The authors were much more interested in the processes that affected the magma after it was formed and do not get into the origin of the magma very much.  But the Mexican belt is a subduction zone and the key is that it is subducting relatively young oceanic crust.  When the crust goes down young and therefore relatively hot, the crust can melt.  The magmas generated when the crust melts are very different than those that form when water is dehydrated from the crust and goes into the mantle and causes melting (the typical process in arcs).&lt;br&gt;&#xA;It turns out that young crust melting gives a very distinct rock that displays a very specific geochemical signature called adakites.  There are adakites all through the Mexican subduction zone.  The Parícutin rocks are right on the border as far as whether they match adakite signatures and they could be partial melts of the slab.  Sr/Y and La/Yb are the keys but they did not analyze Yb and the Sr/Y ratios place the rocks just on the border of the adakite field.  The rocks have very high Al2O3 which is another characteristic of adakites.  &lt;/p&gt;&#xA;" OwnerUserId="3126" LastActivityDate="2015-07-03T22:18:57.113" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5112" PostTypeId="2" ParentId="85" CreationDate="2015-07-03T22:48:10.490" Score="-3" Body="&lt;p&gt;I suggest that all the relatively small earthquakes in Oklahoma that have done minor damage are the result of fracking.  I don't know much about earthquake history in Oklahoma but I would not expect the center of the continent to be that active (Cairo, Illinois area being an exception)&lt;/p&gt;&#xA;" OwnerUserId="3126" LastActivityDate="2015-07-03T22:48:10.490" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5113" PostTypeId="2" ParentId="5093" CreationDate="2015-07-04T01:36:41.263" Score="2" Body="&lt;p&gt;I recently saw a video lecture given that went through a calculation of how the size of volcanoes is related to the mass of a planet.  I don't remember the details or the math but the conclusion was that the smaller the planet the bigger the volcano.  This explains why Olympus Mons on Mars is so much bigger than anything on earth.  I can find a link to the lecture if that will help.  The equations are given in the lecture.  &lt;/p&gt;&#xA;" OwnerUserId="3126" LastActivityDate="2015-07-04T01:36:41.263" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5114" PostTypeId="2" ParentId="5021" CreationDate="2015-07-04T02:38:21.893" Score="4" Body="&lt;p&gt;No, it is not due to lush vegetation (that was not around until just hundreds of millions of years ago).  The period around 2.5 billion years ago is known as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Oxidation_Event&quot; rel=&quot;nofollow noreferrer&quot;&gt;Great Oxygenation&lt;/a&gt; period.  No one knows for sure, but it was probably caused by anaerobic bacteria producing oxygen for the previous billion years.  They basically destroyed their environment by oxygenating Earth.  We have copious quantities of iron-ore formations (the banded iron formations) around this time to prove that the earth basically rusted.  The free iron in the oceans picked up oxygen and precipitated out Fe2O3.  Finally oxygen got high enough about 700,000 years ago to allow the first multicellular life to evolve.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;BTW I think the diagram is pure speculation but would also like to know more about the source&lt;/p&gt;&#xA;" OwnerUserId="3126" LastEditorUserId="6703" LastEditDate="2019-06-26T14:44:53.007" LastActivityDate="2019-06-26T14:44:53.007" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="5115" PostTypeId="2" ParentId="4980" CreationDate="2015-07-04T02:54:34.053" Score="2" Body="&lt;p&gt;The electromagnetic force and related field is a strong force at very small distances (governs the way the proton and electron are held to an atom) but is relatively weak over large distances.  I don't see how that small force could act on processes involved in the convection of the mantle.  If memory serves, the iron in magmas preserves the force of the electromagnetic field on earth at the time the magma cools to form rock. It leaves its imprint but has no affect on the process or origin of magmatism much less the convection that drives plate tectonics &lt;/p&gt;&#xA;" OwnerUserId="3126" LastActivityDate="2015-07-04T02:54:34.053" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5116" PostTypeId="2" ParentId="4962" CreationDate="2015-07-04T03:00:28.103" Score="0" Body="&lt;p&gt;Pangaea consisted of all the tectonic plates that are around today including Antarctica, Africa, NA, SA, Australia, Europe, and Asia (am I forgetting any?).  No one knows why the continents broke apart but there is plenty of speculation.  The best bet is that the convection in the mantle changed.  It drives plate tectonics.  Where to convective cells well up, rifting occurs.  The continents were torn apart in areas that were above these convective cells.  &lt;/p&gt;&#xA;" OwnerUserId="3126" LastActivityDate="2015-07-04T03:00:28.103" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5117" PostTypeId="2" ParentId="5109" CreationDate="2015-07-04T03:05:50.100" Score="7" Body="&lt;p&gt;As with the answer to most things that involves consumption or absorption it's a question of degree, quantity and duration.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Heat&quot;&gt;Heat&lt;/a&gt; is energy that is being transferred.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All life forms require a certain amount of heat to function and survive. Too much heat &lt;strong&gt;and&lt;/strong&gt; not enough heat are detrimental to all life forms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Applying heat to food by cooking it kills most bacteria associated with the food. Likewise freezing food will initially slow life processes of bacteria and enough cold will also kill many types of bacteria.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for Earth's environment, if it does not contain enough heat, climate patterns change, ecosystems suffer and the planet freezes, as it has done on a number of occasions when it experienced &lt;a href=&quot;https://en.wikipedia.org/wiki/Ice_age&quot;&gt;ice ages&lt;/a&gt;. Likewise, with too much heat climate patterns change and ecosystems suffer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth's ecosystem requires a specific range of heat for it to be healthy. This is generally supplied by the Sun but in places can be supplied by the Earth's own geothermal systems, such as volcanic vents, particularly in oceans. Occasional extreme variations in heat can be tolerated if the difference in heat is not too extreme and if the duration of the extreme is short.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider the &lt;a href=&quot;https://en.wikipedia.org/wiki/Effects_of_nuclear_explosions&quot;&gt;detonation of a thermo-nuclear device&lt;/a&gt; in the atmosphere,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the temperatures reached are briefly in the tens of millions of degrees&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is hotter than the Sun and such energy has been released in Earth's environment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ignoring the effects of radiation and only considering the heat produced, such detonations product a huge amount of heat for a &lt;strong&gt;very short time&lt;/strong&gt; in a &lt;strong&gt;very small region&lt;/strong&gt;. This adversely affects life forms and the ecosystem in the area of detonation, but the ecosystem recovers from the effect of the heat and the heat does not affect the climate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If however, there are heat sources covering a large area that is generating a large amount of heat for a prolonged period of time it can affect weather patterns and locally change an ecosystem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the ease of heat exiting Earth's ecosystem it depends on what is in the atmosphere and the proportions of what is in the atmosphere. Cloud cover will retain heat by acting as a blanket. Gases such as methane and carbon dioxide are known for their ability to reflect heat back to the Earth's surface, thus retaining heat in the atmosphere. Increased levels of such gases increases the heat retention within the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-07-04T03:05:50.100" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5118" PostTypeId="2" ParentId="4948" CreationDate="2015-07-04T03:07:42.393" Score="3" Body="&lt;p&gt;The other answers are only partially correct.  Yes the density is the key but the fundamental question is why are the continents less dense than the oceans.  This is what makes the continents float higher - less dense.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason for the density differences is due to plate tectonics.  The continents are derived from two process mostly.  1) subduction zone arc volcanics and 2) accretion of land masses as subduction occurs.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is controversial but I believe that the continental crust formed by direct melting of the oceanic crust in subduction zones starting at least 3 billion years ago.  The older parts of the continental crusts consist of a rock called trondhjemite which has the geochemical characteristics of slab melting in subduction zones.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In contrast, the ocean floor is created at mid ocean ridges in rift zones by direct partial melting of the mantle to form basalt.  Basalt is much more dense than trondhjemite. &lt;/p&gt;&#xA;" OwnerUserId="3126" LastEditorUserId="725" LastEditDate="2016-08-05T00:26:03.567" LastActivityDate="2016-08-05T00:26:03.567" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5119" PostTypeId="2" ParentId="4925" CreationDate="2015-07-04T03:13:40.680" Score="0" Body="&lt;p&gt;Rock forming minerals vary with the types of rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sedimentary rocks dominate the surface of the earth but igneous and metamorphic rocks dominate the rest of the crust. So you will need to look at each type depending on what part of the crust you are speaking about.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The major igneous minerals are those found in Bowen's reaction series.  The sedimentary minerals are dominated by the most durable (those that can withstand erosion out of igneous rocks; quartz is a good example) or the chemical precipitates that form rocks like limestone (calcite).&lt;/p&gt;&#xA;" OwnerUserId="3126" LastEditorUserId="725" LastEditDate="2016-12-31T06:54:15.127" LastActivityDate="2016-12-31T06:54:15.127" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5120" PostTypeId="2" ParentId="4912" CreationDate="2015-07-04T04:13:48.313" Score="2" Body="&lt;p&gt;A quote from the summary of the book you listed:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;feeding torrents of freshwater into ocean basins that rapidly filled&#xA;  to present levels. The removal of the enormous weight of ice at high&#xA;  latitudes caused the crust to bounce back triggering earthquakes in&#xA;  Europe and North America and provoking an unprecedented volcanic&#xA;  outburst in Iceland. A giant submarine landslide off the coast of&#xA;  Norway sent a tsunami crashing onto the Scottish coast while around&#xA;  the margins of the continents the massive load exerted on the crust by&#xA;  soaring sea levels encouraged a widespread seismic and volcanic&#xA;  rejoinder.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Could not access the other links.  This is clearly bordering on pseudoscience.  I admit I have not read the book but the summary makes it sound like junk science.  As a scientist I am skeptical and all of this seems like a stretch. I sure would like to know how crustal rebound (isotasy) affects a volcanic hot spot in the middle of the ocean.  The hot spot is most likely generated at the core-mantle boundary where convective cells in the core meet the mantle and melt it. The whole scenario sounds like a bad movie. Is there anything that someone will not blame on global warming? And how would we ever know that a landslide in Norway was due to crustal rebound/global warming?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the author is disingenuous.  Even if he is correct, he implies that the changing climate in the past and any potential events associated with that changing climate might be related to changing climate today.   But climate change of the recent past has been due to the earth cycles set out by Milankovich and not to man-made global warming.  How can the two be compared when in the past we had a 6 degree change and now we are looking at only about a 1 degree change up until now.  Sounds like he is desperate to sell his book and hypotheses.&lt;/p&gt;&#xA;" OwnerUserId="3126" LastEditorUserId="725" LastEditDate="2016-12-31T06:56:42.953" LastActivityDate="2016-12-31T06:56:42.953" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5121" PostTypeId="2" ParentId="4876" CreationDate="2015-07-04T04:22:04.373" Score="2" Body="&lt;p&gt;I would argue that plate tectonics is the major reason their is elevation on the surface of the earth.  But let me be clear that the oceans are not the major eroders of land - running water on the land is (from rain and snow).  You are correct to assume that as the earth cools, plate tectonics will subside and the rate of erosion will overcome the rate of uplift due to plate tectonics.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for making estimates about how long it will take to do this, I would not wish to hazard a guess.  Earth has been going strong for billions of years and it probably has a few billion more years left.  &lt;/p&gt;&#xA;" OwnerUserId="3126" LastActivityDate="2015-07-04T04:22:04.373" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5123" PostTypeId="1" AcceptedAnswerId="5128" CreationDate="2015-07-04T04:45:15.077" Score="6" ViewCount="17434" Body="&lt;p&gt;Just as the title says, I heard about this term but am not sure how it works.&lt;/p&gt;&#xA;" OwnerUserId="3087" LastEditorUserId="64" LastEditDate="2015-07-06T16:58:17.480" LastActivityDate="2018-03-28T19:56:35.830" Title="What is a temperature inversion and can it trap smog/pollution?" Tags="|meteorology|pollution|air-pollution|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5124" PostTypeId="2" ParentId="4872" CreationDate="2015-07-04T06:40:23.913" Score="4" Body="&lt;p&gt;While there are specific cases of continental sinking, I think this needs to answered on a global scale in which continental lithosphere is significantly more buoyant than 1) the mantle and 2) oceanic lithosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a continent to sink you either need to add mass to the continent (pushing down on the mantle causing a diverging mantle flow underneath) or you need to push mantle from underneath the continent away from internal forces. The latter case is difficult to see happening unless there is a heating gradient caused by mantle heterogeneity, there is certainly no evidence of that. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, in regards to the effects of mantle flow on sea-level rise, I encourage you to read the seminal piece of this field, &lt;a href=&quot;http://www.sciencemag.org/content/319/5868/1357.short&quot; rel=&quot;nofollow&quot;&gt;Muller et al. 2008&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mantle flow can have just as great (if not greater) effect on the sea level relative to the continent as it can on the height of continents. But because Isostasy and erosion largely governs the height of the continent, its hard to see some complex dynamic where you get global continental sinking (meaning flow is completely divergent under all continents) seems rather extraordinary and not physically consistent with our geophysical models. Subduction zones along the ring of fire certainly do their best to cycle the mantle underneath the continental lithosphere, for example.    &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="32" LastEditDate="2015-07-04T06:47:18.920" LastActivityDate="2015-07-04T06:47:18.920" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5125" PostTypeId="1" AcceptedAnswerId="5136" CreationDate="2015-07-04T08:15:23.977" Score="9" ViewCount="503" Body="&lt;p&gt;Is everything in the water column going to be affected?&lt;/p&gt;&#xA;" OwnerUserId="3087" LastEditorUserId="111" LastEditDate="2015-07-05T19:49:47.657" LastActivityDate="2015-07-06T16:44:30.757" Title="How does a tsunami affect biology and other matter in its path while in deep water" Tags="|ocean|waves|tsunami|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5126" PostTypeId="2" ParentId="5125" CreationDate="2015-07-04T13:49:53.883" Score="1" Body="&lt;p&gt;Remember that a wave when it passes moves every particle up and down (with no horizontal component) so in deep water tsunamis have very little affect on anything.  In addition, the wavelength/amplitude of these waves is huge so the water rises very gently and it is hardly noticed in deep water. In fact, the safest place to be when a tsunami is coming (beside high ground) is out at sea in deep water.  &lt;/p&gt;&#xA;" OwnerUserId="3126" LastActivityDate="2015-07-04T13:49:53.883" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="5127" PostTypeId="2" ParentId="5123" CreationDate="2015-07-04T14:01:48.070" Score="1" Body="&lt;p&gt;this is straight from &lt;a href=&quot;https://en.wikipedia.org/wiki/Inversion_(meteorology)&quot; rel=&quot;nofollow&quot;&gt;Wikipedia&lt;/a&gt;: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In meteorology, an inversion is a deviation from the normal change of an atmospheric property with altitude. It almost always refers to a &quot;temperature inversion&quot;, i.e. an increase in temperature with height, or to the layer (&quot;inversion layer&quot;) within which such an increase occurs.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;An inversion can lead to pollution such as smog being trapped close to the ground, with possible adverse effects on health. An inversion can also suppress convection by acting as a &quot;cap&quot;. If this cap is broken for any of several reasons, convection of any moisture present can then erupt into violent thunderstorms. Temperature inversion can notoriously result in freezing rain in cold climates.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="3126" LastEditorUserId="64" LastEditDate="2015-07-06T15:33:57.217" LastActivityDate="2015-07-06T15:33:57.217" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5128" PostTypeId="2" ParentId="5123" CreationDate="2015-07-04T14:08:02.213" Score="12" Body="&lt;p&gt;Normally, temperature broadly &lt;a href=&quot;https://en.wikipedia.org/wiki/Lapse_rate&quot;&gt;decreases with altitude&lt;/a&gt;, and convection is effective: locally warmer air will rise, and cooler air will fall. A &lt;a href=&quot;https://en.wikipedia.org/wiki/Inversion_(meteorology)&quot;&gt;temperature inversion&lt;/a&gt; is where the air temperature &lt;strong&gt;rises&lt;/strong&gt; with altitude. This means that convection is less effective because the air above is already warmer, and so there is less mixing of air between altitudes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since pollution is generally produced at ground level, temperature inversions can trap the pollution (e.g. smog) at ground level. &lt;/p&gt;&#xA;" OwnerUserId="534" LastActivityDate="2015-07-04T14:08:02.213" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5129" PostTypeId="1" CreationDate="2015-07-05T01:05:24.070" Score="6" ViewCount="4224" Body="&lt;p&gt;In a related question (&lt;a href=&quot;https://earthscience.stackexchange.com/questions/4555/does-bathymetry-affect-ocean-topography-height&quot;&gt;Does bathymetry affect ocean topography/height?&lt;/a&gt;), the effect of atmospheric pressure on sea level is described as &quot;inverted barometer&quot;. What does it mean? How does it get measured?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2021-07-12T23:19:54.070" Title="What is the inverted barometer effect?" Tags="|ocean|sea-level|barometric-pressure|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5130" PostTypeId="2" ParentId="5129" CreationDate="2015-07-05T01:22:34.417" Score="9" Body="&lt;p&gt;In a barometer, you have a tube submerged in a fluid, with a vacuum at the top. If air pressure is low, the fluid can drain out of the tube, letting you read how much lower the air pressure is than some reference value. So, the height of the fluid in the tube goes down as air pressure goes down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &quot;inverted barometer&quot; is, in my opinion, much easier to understand.  Over the oceans, high pressure systems push down on the water, lowering sea surface heights a bit. Here, sea surface height goes down as air pressure goes up.  So, it's inverted from a barometer.  But it's really just saying &quot;If I push on something, it'll move&quot; :-p&lt;/p&gt;&#xA;" OwnerUserId="1342" LastActivityDate="2015-07-05T01:22:34.417" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5131" PostTypeId="1" AcceptedAnswerId="5133" CreationDate="2015-07-05T05:59:19.460" Score="7" ViewCount="28977" Body="&lt;p&gt;Even at similar latitudes they appear to be quite different from one another.&lt;/p&gt;&#xA;" OwnerUserId="3087" LastActivityDate="2020-01-21T16:40:46.380" Title="Why is the Ocean water on the west Coast so cold comparing to the East coast?" Tags="|ocean|temperature|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="5132" PostTypeId="2" ParentId="5109" CreationDate="2015-07-05T07:42:30.100" Score="4" Body="&lt;p&gt;Changes to temperature are harmful to the environment - or, to use a perhaps-less-contentious wording, changes to temperature change the environment. The important thing here is to understand how heat and temperature are related. This can be considered on local and global scales.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Locally&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;If a continuous point source of heat is sufficiently intense, then it will raise the temperature of its immediate surroundings, and this can affect local ecosystems. Examples of this are the warm water outfalls from &lt;a href=&quot;http://www.ukmarinesac.org.uk/activities/water-quality/wq9_8.htm&quot; rel=&quot;nofollow&quot;&gt;power station cooling&lt;/a&gt;, and heating of soil by buried power cables.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On a slightly wider scale, anthropogenic heat is a contributor to urban heat island effects.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Globally&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;There is a continuous flux of energy arriving on the planet from the sun (and, to a far lesser extent, from the inside of the planet), and leaving via radiation into space. A complex system of factors determines the equilibrium between these, and the resulting global temperatures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The amount of energy produced by human activity worldwide (sometimes termed &quot;Anthropogenic heat release&quot;) is in the order of 0.01% of the amount of energy arriving from the sun. At the moment, therefore, the global effects of heat generation such as you refer to are negligible, especially when compared with the effects of the chemical changes in the atmosphere that cause global warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See also: (not duplicate) &lt;a href=&quot;https://earthscience.stackexchange.com/questions/3041/how-does-anthropogenic-heating-affect-global-warming&quot;&gt;How does anthropogenic heating affect global warming?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2015-07-17T18:17:33.867" LastActivityDate="2015-07-17T18:17:33.867" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5133" PostTypeId="2" ParentId="5131" CreationDate="2015-07-05T10:46:02.663" Score="15" Body="&lt;p&gt;&lt;a href=&quot;http://earth.usc.edu/~stott/Catalina/Oceans.html&quot; rel=&quot;noreferrer&quot;&gt;This&lt;/a&gt; is a good overview of ocean surface currents, which includes a schematic like this one:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/O6Icf.jpg&quot; alt=&quot;Surface currents&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the mid-latitudes, you get gyre circulations that move poleward along the eastern coasts of continents (the western edges of the ocean), bringing warm water. The water off the east coasts of these places is thus warmer than you would expect for that latitude. The return flow on the eastern edges of ocean basins (west coast of continents) brings cold water from poleward of that latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are a few things to note about this circulation, though, since that analysis applies to the mid-latitudes only. There are opposite gyres closer to the poles that make the east coasts much colder than expected. (Compare the Alaska current to the Labrador, which is off the east coast of Canada.) The circulation near the equator is a lot more complex and interesting, especially where it meets up with other gyres.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are some strange and fascinating reasons why the circulation is the way it is, but &lt;em&gt;that&lt;/em&gt; answer is the result of an entire oceanography course...&lt;/p&gt;&#xA;" OwnerUserId="1342" LastActivityDate="2015-07-05T10:46:02.663" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5134" PostTypeId="1" AcceptedAnswerId="5138" CreationDate="2015-07-05T13:19:19.737" Score="11" ViewCount="1274" Body="&lt;p&gt;I imagine that human agriculture had a major effect on the composition of flora across the planet's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Did the transition from gathering to growing have a measurable effect on climate? If so, what was it?&lt;/p&gt;&#xA;" OwnerUserId="828" LastActivityDate="2016-09-09T19:07:07.150" Title="Did the Neolithic Revolution have an effect on the earth's climate?" Tags="|climate|climate-change|paleoclimatology|human-influence|agriculture|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5135" PostTypeId="1" CreationDate="2015-07-05T22:17:25.100" Score="9" ViewCount="475" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;A maar is a shallow volcanic crater with steep sides that is surrounded by tephra deposits. The tephra deposits are thickest near the crater and decrease with distance from the crater.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/pG4LK.jpg&quot; alt=&quot;Three pictures of maars&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://geology.com/stories/13/maar/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://geology.com/stories/13/maar/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have looked at about 70 craters formed by this type of explosion. I have gathered several data points such as diameter, depth, and elongation. I am now trying to use this data to attempt to find this type of crater in some regions of Mars. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earlier attempts have ended in failure. Mainly because I am mistaking maar craters with supervolcanos, and impact craters with maars, and vice versa. The craters that I have looked at are very young. Mars's volcanic activity is believed to have ceased many billions years ago. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are some good ways to identify this type of geologic feature from other potential doppelgangers? I have no data points for old maar craters mainly because they are too eroded to measure anything, and/or have large scoria cones that have erased their once-elliptical shapes.   &lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="543" LastEditDate="2016-01-29T05:50:08.137" LastActivityDate="2016-04-01T15:16:44.177" Title="Impact craters vs volcanic explosions on Mars" Tags="|geophysics|geology|planetary-science|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5136" PostTypeId="2" ParentId="5125" CreationDate="2015-07-05T22:40:08.990" Score="7" Body="&lt;p&gt;The answer to your question, based on linear theory, is no. The short answer is that the slope of these waves is very small, and the displacement of the particle paths is proportional to (ak) (times, perhaps, a depth dependent term) with a the wave amplitude and k its wavenumber. Now let's make this answer rigorous. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recall, for irrotational inviscid 2 dimensional water waves the governing equation is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\nabla^2 \phi = 0$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\nabla^2 \equiv \partial_{xx}+\partial_{zz}$ and $\phi$ is the velocity potential. We require particles on the free surface to remain there, and for the pressure to be continuous across the air-water interface, which gives us (assuming the atmospheric pressure to be 0) our surface boundary conditions &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\left.\eta_t+\phi_x\eta_x = \phi_z\right|_{z=\eta}; \quad \quad \left. \phi_t+\frac{1}{2}(\nabla \phi)^2 +gz=0\right|_{z=\eta},$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\eta(x,t)$ is the free surface displacement. Finally, we require the bottom to be impermeable, hence&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\phi_z = 0 \quad @ z= -h$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;for $h$ the depth of the water. These are a closed set of equations. Note, the governing equation, ie Laplace's equation, is linear and hence simple to solve. However, the free surface conditions are nonlinear, and more significantly, evaluated at a moving interface. This last condition makes these equations very difficult to solve. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, to make progress, we generally take asymptotic expansions of these equations. Here, we'll just linearize the equations about some small parameter $\epsilon = ak$ for characteristic wave amplitude $a$ and wavenumber $k$. We will also consider periodic monochromatic waves, so that one can show that the following $\eta,\phi$ satisfy the governing equations to first order in $\epsilon$: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\eta = a \cos \theta; \quad \phi = a\omega \sin \theta \frac{\sinh k(z+h)}{\sinh kh},$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\omega$ is the angular frequency given by the dispersion relationship&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\omega = \sqrt{gk \tanh kh},$$&#xA;and $\theta\equiv kx-\omega t$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer your question, we would like to know the behavior of a particle with position $(\xi+x_o,\zeta+z_o)$ originally located at some position $(x_o,z_o)$.This is the Lagrangian description of the fluid. Recall, we can relate the Eulerian and Lagrangian descriptions of a fluid through the velocity field, that is &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\phi_x = \frac{d \xi}{d t}; \quad \phi_z = \frac{d\zeta}{dt}.$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Substituting in the relations for $\phi$ found above, and then integrating in time, we find &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\xi =-a\frac{\cosh k(z_o+h)}{\sinh kh} \sin \theta_o; \quad \quad \zeta = a\frac{\sinh k(z_o+h)}{\sinh kh} \cos \theta_o,$$&#xA;where $\theta_o =kx_o - \omega t$. We note that the particle displacements from the origin scales with the wave amplitude $a$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, we can eliminate $\theta_o$ by squaring the expressions for the particle position to find &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\frac{\xi^2}{\left(a\frac{\cosh k(z_o+h)}{\sinh kh} \right)^2 } +\frac{\zeta^2}{\left(a\frac{\sinh k(z_o+h)}{\sinh kh} \right)^2 }= 1$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;which describes an ellipse. I've attached a figure from Kundu and Cohen which illustrates this. &lt;img src=&quot;https://i.stack.imgur.com/cdq5k.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now we can finally talk about some physics, and answer your question. For deep water waves, when $kh \ll 1$, the above relation reduces to the equation for a circle, hence the particles have a circular orbit which decays with depth (with an e-folding scale that goes like the wave number). For shallow water waves, i.e.  $kh$ small, our equation describes an ellipse with a semi major axis that is much much larger than the semi minor axis, hence there's is nearly horizontal motion that doesn't decay much with depth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tsunamis have wavenumbers that are large enough so that even in the middle of the ocean they fall into the shallow water regime, meaning that the particle trajectories are approximately very flat ellipses, or horizontal lines, and this does not decay with depth. However, their deviations from their origin will be very small, as their slope $ak$ is very very small, e.g. $\mathcal{O}(1^{-5})$ for numbers I looked up online. Therefore, it's very unlikely that this will have much of an effect on a passive tracer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, the story is very different as the wave approaches shore and steepens. But this is a different story for a different day. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope this helps. Feel free to ask any other questions,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nick&lt;/p&gt;&#xA;" OwnerUserId="3034" LastEditorUserId="192" LastEditDate="2015-07-06T16:44:30.757" LastActivityDate="2015-07-06T16:44:30.757" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5137" PostTypeId="2" ParentId="845" CreationDate="2015-07-06T07:04:38.850" Score="-1" Body="&lt;p&gt;An interesting observation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I look at the series of craters which mark the procession of various hotspots, such as yellowstone, their size and output does appear to be increasing.  Same with hawaii and madagascar (if you ignore the deccan traps.).  Although that might just be because of erosion, i donno.&lt;/p&gt;&#xA;" OwnerUserId="3123" LastActivityDate="2015-07-06T07:04:38.850" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5138" PostTypeId="2" ParentId="5134" CreationDate="2015-07-06T07:37:35.683" Score="7" Body="&lt;p&gt;Raising herd animals would likely contribute more than mere farms.  Many farms simply produce feed for animals anyway, and this can lead to an inflated population which can wreck havoc when released in the wild to graze.  That said, with the exception of Egypt and a few rare cases, every agricultural society eventually failed because they could either could not keep up with the deposits of silt clogging their water works, or they could not contend with the the rising salinity of soil, caused by prolonged irrigation.  The evaporation of water leaves behind an excess of mineral salts, and eventually a field's production drops and the desert takes over.  The usual method people employ to contend with these issues is to build more canals and irrigate more land elsewhere.  So for a few thousand years agriculture societies have been converting land to desert and this no doubt this would have effected the climate.  But probably only a scant iota when compared to the last 100 years of agriculture . . . &lt;/p&gt;&#xA;" OwnerUserId="3123" LastActivityDate="2015-07-06T07:37:35.683" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5139" PostTypeId="1" AcceptedAnswerId="5141" CreationDate="2015-07-06T12:42:50.457" Score="8" ViewCount="1140" Body="&lt;p&gt;CO2 is a common agent in fire extinguishers, which suppresses fire.  How does this same chemical contribute to global warming when it also puts out fires? &lt;/p&gt;&#xA;" OwnerUserId="3133" LastEditorUserId="64" LastEditDate="2015-07-06T14:51:22.343" LastActivityDate="2015-07-06T15:28:04.433" Title="How does CO2 contribute to global warming?" Tags="|climate-change|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5140" PostTypeId="2" ParentId="4872" CreationDate="2015-07-06T13:30:26.057" Score="-3" Body="&lt;p&gt;I am considering a problem that was not raised yet properly, although some has studied how can Earth size and shape change with the many phenomena that occur inside Earth. We tend to believe that continental plates are able of rising up but not the contrary, but not because of scientific reasons, and so we must be suspicious of ourselves. I think that the problem can only be solved by measuring, not by theoretical considerations. I see four possible types of measurements: surface gravity, Earth rotation, Moon-Earth distance and satellites altimetry in free orbiting. All very difficult and influenced by other phenomena. I think that VLBI measurements of Earth rotation present the clearest evidence because the already four decades of increasing rotation speed is difficult to explain without considering a decrease of Earth's equator size. Anyhow, I think we should start considering this possibility, which is not being done by now.&lt;/p&gt;&#xA;" OwnerUserId="2905" LastActivityDate="2015-07-06T13:30:26.057" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5141" PostTypeId="2" ParentId="5139" CreationDate="2015-07-06T15:28:04.433" Score="19" Body="&lt;p&gt;It seems that you are wondering how a chemical that prevents heat (putting out a fire) can also cause heating (global warming).  These two things happen through unrelated processes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fire extinguishers that use CO2 act by displacing oxygen.  The CO2 doesn't directly interact with the fire but just takes up space so that oxygen cannot interact with the fire.  There is a secondary effect that the CO2 exiting the extinguisher is cooler than the air it is displacing so it helps to remove heat from the fire (by putting it somewhere else).&#xA;These are reasons that CO2 extinguishers are not suitable for all kinds of fire suppression, particular for fires that have oxidizers and do not rely on atmospheric oxygen for combustion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The contribution to global warming from CO2 (and all other greenhouse gases) is a radiative effect.  Every molecule has specific frequencies of electromagnetic radiation they absorb and emit.  The earth (and all things) emit electromagnetic radiation based upon its surface temperature.  This energy would be lost to space (cooling the earth) except that the greenhouse gases absorb radiation at the same wavelengths the earth emits at.  This means that, e.g. CO2, intercepts this energy headed for space and instead absorbs it, causing the CO2 to warm up a little.  This CO2 also emits radiation but will emit less than it absorbs (and some of its emission is back toward the earth, not space), so there is a net energy gain due to atmospheric GHG, which causes warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, the mechanisms that CO2 contributes to global warming and fire suppression are unrelated (radiative vs displacement) which is why this molecule can be used in these seemingly contradictory applications.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-07-06T15:28:04.433" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5142" PostTypeId="2" ParentId="5123" CreationDate="2015-07-06T16:55:59.087" Score="6" Body="&lt;p&gt;As others have noted, a temperature inversion is a layer where temperature increases with height.  This is called an inversion because the normal temperature profile decreases with height.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A temperature inversion can trap pollution.  Factors that influence this are the environmental temperature profile, the height of the chimneys or smokestacks that expel pollution and the temperature of the pollutants as they leave the smokestacks. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the temperature of the air coming from the smokestacks is warmer than its surrounding and the lofted pollutants aren't too heavy, the air will be buoyant and rise.  Even in the case of heavy pollutants, those heavy particles tend to fall to the ground near the smokestacks, polluting the ground environment while the rest of the stuff coming out of the stacks rises.  This is particularly evident around a coal stack in the winter as the snow steadily turns orange near the stacks.  The lofted pollutants will rise with the air they are carried by until they are no longer buoyant and then they will stabilize in height where they find equilibrium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To demonstrate, consider the following two scenarios.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/EdwG8.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This scenario has an environmental temperature profile based on a surface temperature of 20 C, a dewpoint around 8 C, no capping inversion and a well mixed boundary layer.  The black line represents the temperature a parcel lifted from the surface would have.  The pollutants are being emitted from a smokestack with a height around 300 m with a temperature around 22 C.  I've also assumed no water vapor coming out of the smokestacks.  In this case the air from the smokestack (red) is always warmer than the environment and it escapes the boundary layer and rises well above the surface.  This pollution is not trapped.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/3ehlT.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This scenario has a capping inversion between 900 and 850 mb but is otherwise the same as the previous example (same surface temperature and dewpoint).  The pollutants have the same properties as the first scenario.  In this case, however, due to the temperature inversion there is a height where the environment becomes warmer than the pollutants.  If the pollutant ties to rise any higher it will be negatively buoyant and will oscillate around the height of neutral buoyancy (see &lt;a href=&quot;https://en.wikipedia.org/wiki/Brunt%E2%80%93V%C3%A4is%C3%A4l%C3%A4_frequency&quot; rel=&quot;nofollow noreferrer&quot;&gt;Brunt–Väisälä frequency&lt;/a&gt;).  In this case the pollution will be trapped around 860 mb, which is around 1250 m.  This isn't too close to the ground but in a well mixed boundary layer this pollution eventually will be mixed throughout the boundary layer.  This pollution is trapped.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both of these scenarios are on warm well-mixed days.  Bigger problems tend to happen at night or early morning and in the cold season.  In these cases deep inversions that start at the surface tend to form and if smokestacks are not very tall this can cause pollution to be trapped very close to the ground.  This kind of temperature structure will cause the pollutant to spread out at low heights.  In places where these type of inversions are frequent it is important that smokestacks are built tall enough to emit pollution above the inversion height.  The picture below demonstrates how this kind of pollution trapping can look.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/qgopa.jpg&quot; alt=&quot;enter image description here&quot;&gt;&#xA;&lt;sub&gt;Image by JohanTheGhost, wikimedia commons. &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:SmokeCeilingInLochcarron.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://commons.wikimedia.org/wiki/File:SmokeCeilingInLochcarron.jpg&lt;/a&gt; &lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-07-06T16:55:59.087" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5143" PostTypeId="1" CreationDate="2015-07-06T12:11:04.380" Score="9" ViewCount="4989" Body="&lt;p&gt;I understand that volcanoes are caused by the heat that causes high intense pressure below the Earth's surface. This intense pressure gets released and causes magna which becomes hot lava to flow out from inside the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why does it happen in New Zealand or any cold countries? There is no way that the Earth will be over-heated there.&lt;/p&gt;&#xA;" OwnerDisplayName="dexterous_stranger" LastEditorUserId="502" LastEditDate="2015-07-08T05:41:59.423" LastActivityDate="2015-07-10T19:03:14.980" Title="Why does New Zealand and cold countries have volcanoes?" Tags="|geophysics|volcanology|" AnswerCount="5" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5144" PostTypeId="2" ParentId="5143" CreationDate="2015-07-06T13:52:38.433" Score="7" Body="&lt;p&gt;The countries you refer to are only cold at the surface of Earth. Once you dig down a short ways (I'm not a geologist, so I hope they forgive me if I ballpark a number), say a hundred meters or so, the temperatures become fairly consistent all across the globe. Furthermore, the buildup of pressure under the surface has no relevance to the surface temperature above. Tectonic activity, hot spots, and tidal friction (not so much that last one for Earth) are what cause the heat and pressure to form volcanoes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Places that lie near subduction zones - which are converging fault lines where the sea floor is pushed under another plate - are prone to volcanism because the sinking plate puts increased pressure and some friction on the (in New Zealand's case) continental plate. You end up with a compactified continental plate (mountains) and large pressure/heat buildup (volcanoes). That is the case with New Zealand. Other cold areas, like Iceland, can be formed directly from diverging faults - regions where tectonic plates are separating and allowing the mantle to flow to the surface. This creates volcanism that manifests more as things like hot springs and lava tubes rather than as big, mountainous, andesite volcanoes. Hot spots are a different entity entirely. A hot spot is not necessarily related to tectonic activity, it is simply a region of the mantle that is over-heated and so causes volcanism at the surface above it. This spot does not move with the rest of a tectonic plate, which is why the Hawaiian island chain has moved progressively; the plate moved the islands off the hot spot, so there's now a string of dead volcanic islands that are arranged by age. Iceland also has some hotspot activity on top of being on a diverging fault. Regardless of how cold it is, in the mantle below Iceland the temperatures are abnormally high. This, again, is possible because the surface temperatures do not penetrate far enough down to affect the mantle temperatures in any significant way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regardless the cause of the volcanism, it has absolutely nothing to do with surface temperature. That only impacts the immediate surface of Earth and not in any way that would either prevent or stimulate the buildup of subsurface pressure and heat.&lt;/p&gt;&#xA;" OwnerUserId="3134" OwnerDisplayName="Jims Bond" LastActivityDate="2015-07-06T14:02:12.737" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="5145" PostTypeId="2" ParentId="5143" CreationDate="2015-07-06T14:53:26.420" Score="15" Body="&lt;p&gt;Surface temperatures on Earth are a consequence of solar heating and radiative cooling - in other words, the heat energy which drives climate comes from sunlight falling on the Earth &quot;now&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, the heat energy driving volcanism is left over from the formation of the Earth (4.5 billion years ago), stored deep inside the planet, with some additional heat generated from the radioactive decay of elements contained in the rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Deep within the Earth, the temperature is on the order of 5000-7000&amp;nbsp;K. It's obviously much cooler at the surface. The high temperatures cause the rock and metal of which the Earth is composed to melt. The temperature gradient results in a slight density gradient, which drives convection (flow of hot material up to the surface). When that hot material breaks through the surface, you have a volcano.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider that the hottest places on Earth (in terms of climate) don't have surface temperatures anywhere close to what it takes to melt rock (maybe 50&amp;nbsp;°C compared to 1000s of °C). Heat can only move from where the temperature is higher to where it is lower. Less heat falls on the planet from the Sun than the Earth radiates away into space; that difference is heat finding its way up to the surface from within. So, the heat driving volcanoes cannot possibly be coming from sunlight striking the Earth; it can only come from heat stored inside the planet from long ago. Consider also that the difference in temperature between the hottest places on the Earth and the coldest (in terms of climate) differ by little more than 100&amp;nbsp;°C. That's a tiny fraction of the temperature difference between molten magma and even the hottest desert. Bottom line: climate has no effect on volcanic activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the Earth is losing more heat to space than is falling on it from the Sun, and that heat is coming up from below, the core is gradually cooling. But there is so much heat inside the Earth and the rate is so slow that our Sun will die before Earth's core cools enough to solidify.&lt;/p&gt;&#xA;" OwnerUserId="1210" OwnerDisplayName="Anthony X" LastEditorUserId="502" LastEditDate="2015-07-10T19:03:14.980" LastActivityDate="2015-07-10T19:03:14.980" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5146" PostTypeId="2" ParentId="5143" CreationDate="2015-07-07T02:39:06.093" Score="8" Body="&lt;p&gt;The Earth's surface temperature is largely determined by the amount of energy it receives from the Sun  and how much of that energy is reflected back into the cosmos. Weather system circulate that energy in the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Heat within the Earth is the result of two main processes, residual heat from planetary accretion and heat from radioactive decay. The main decay elements are potassium-40, uranium-238, uranium-235, and thorium-232 . The temperature of the Earth increases with depth. For most of the Earth, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Geothermal_gradient&quot; rel=&quot;nofollow&quot;&gt;geothermal gradient&lt;/a&gt; (the rate at which temperature increases) particularly in the crust, is $25$ $^oC$ per km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In &lt;a href=&quot;https://en.wikipedia.org/wiki/Subduction&quot; rel=&quot;nofollow&quot;&gt;subduction zones&lt;/a&gt;, where one tectonic plate goes under another tectonic plate (two plates converge), localized heating occurs due to friction between the plates. Subduction zones are locations with high rates of volcanism, earthquakes and mountain building; as occurs in New Zealand.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Hotspot_%28geology%29&quot; rel=&quot;nofollow&quot;&gt;Geological hotspots&lt;/a&gt; are volcanic locations where it is thought the mantle is anomalously hot compared to the surrounding mantle. They occur on or near plate boundaries, or far away from them. Hawaii is a hotspot away from a plate boundary and in the middle of the largest ocean on Earth. Yellowstone is a hotspot on land, near the plate boundaries along the west coast of North America. Iceland is thought to be a hot spot on a diverging plate boundary in the middle of the Atlantic Arctic region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Volcanism&quot; rel=&quot;nofollow&quot;&gt;Volcanism&lt;/a&gt; of Earth has nothing to do with the surface temperature of the planet, it's all about geological processes where molten rock is forced to the surface of the planet under pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, volcanism isn't confined to the Earth. Mars was once volcanic, Venus still is, as is the Jovian moon &lt;a href=&quot;https://en.wikipedia.org/wiki/Io_%28moon%29&quot; rel=&quot;nofollow&quot;&gt;Io&lt;/a&gt;, the Saturnine moon &lt;a href=&quot;https://en.wikipedia.org/wiki/Enceladus&quot; rel=&quot;nofollow&quot;&gt;Enceladus&lt;/a&gt; and the Neptunian moon &lt;a href=&quot;https://en.wikipedia.org/wiki/Triton_%28moon%29&quot; rel=&quot;nofollow&quot;&gt;Triton&lt;/a&gt;. These are examples of &lt;a href=&quot;http://geology.com/articles/active-volcanoes-solar-system.shtml&quot; rel=&quot;nofollow&quot;&gt;volcanism within our solar system&lt;/a&gt;. Except for Venus, all the other locations of volcanism in the solar system have very cold surface temperatures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On Io, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Magma erupts onto the surface from vents on the floor of paterae or on the plains from fissures, producing inflated, compound lava flows similar to those seen at Kilauea in Hawaii&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Whereas, Enceladus and Triton experience &lt;a href=&quot;https://en.wikipedia.org/wiki/Cryovolcano&quot; rel=&quot;nofollow&quot;&gt;cryovolcanism&lt;/a&gt;, where ice and water are ejected under pressure.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2015-07-08T02:56:29.797" LastActivityDate="2015-07-08T02:56:29.797" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5147" PostTypeId="2" ParentId="5143" CreationDate="2015-07-07T03:09:30.313" Score="4" Body="&lt;p&gt;As others have pointed out, the surface temperature does not effect volcanic activity and this is related to the movement of two (or more) plates relative to each other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The border of the Pacific and Australian plates passes through the south island of NZ, which leads to earthquakes and volcanoes. The border around the Pacific Plate is known as the ring of fire, and almost all regions along it are prone to Earthquakes and Volcanoes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is why Southern parts of Australia, despite being at the same latitude as much of New Zealand and in the same general area of the world, are not prone to earthquakes or volcanoes, they are at the centre of a plate instead of the edge.&lt;/p&gt;&#xA;" OwnerUserId="978" LastActivityDate="2015-07-07T03:09:30.313" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5148" PostTypeId="1" AcceptedAnswerId="5156" CreationDate="2015-07-07T05:44:58.050" Score="13" ViewCount="13952" Body="&lt;p&gt;In my local area there is a creek which dries up completely in the summer and is flowing strongly in the winter. Is it the case that, at the location where the creek dries up, it continues flowing underground?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If so does it take the same trajectory as the creek? At what typical depths does it start flowing &quot;forward&quot;?&lt;/p&gt;&#xA;" OwnerUserId="3087" LastActivityDate="2015-07-13T14:18:28.267" Title="Do rivers/creeks flow underground when they dry up at the surface?" Tags="|rivers|groundwater|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5149" PostTypeId="2" ParentId="5143" CreationDate="2015-07-07T05:53:20.797" Score="4" Body="&lt;p&gt;This is a pure statistical response but the answer is clear  and makes sense when you think about the fact that practically all of New Zealand lies on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ring_of_Fire&quot; rel=&quot;nofollow&quot;&gt;Ring of Fire&lt;/a&gt; which houses 75% of the world's volcanos.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ring of fire runs across the entire globe and is independent of the climate.&lt;/p&gt;&#xA;" OwnerUserId="3087" LastEditorUserId="3087" LastEditDate="2015-07-07T06:26:35.733" LastActivityDate="2015-07-07T06:26:35.733" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5150" PostTypeId="2" ParentId="5148" CreationDate="2015-07-07T13:25:45.560" Score="11" Body="&lt;p&gt;Water in liquid state always takes the fastest route to lower altitude. All rainwater would flow vertically down to the groundwater surface if not the permeability was &lt;a href=&quot;https://en.wikipedia.org/wiki/Darcy%27s_law&quot; rel=&quot;noreferrer&quot;&gt;limited&lt;/a&gt; by the &lt;a href=&quot;http://all-geo.org/highlyallochthonous/2011/01/geology-is-destiny-globally-mapping-permeability-by-rock-type/&quot; rel=&quot;noreferrer&quot;&gt;material properties&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The permeability controls how fast water &lt;a href=&quot;https://en.wikipedia.org/wiki/Surface_runoff&quot; rel=&quot;noreferrer&quot;&gt;infiltrate&lt;/a&gt; and penetrate the material. For example, can surface runoff water flow on top of a hard road coating, while water from a watering-can goes into the soft soil in the flower-bed. Gravel, sand and fractured rocks have high permeability whiles shale and non-fractured igneous rock have low permeability. So low, that in many cases it appears to be totally impenetrable on a human time scale. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same goes for a river. If the river flows on permeable rocks, typical sediments deposited by the river itself &lt;em&gt;(see picture)&lt;/em&gt;, ground water will also flow in the sediments under the river bed, permitting that water is still entering upstream. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A better way to understand a river or lake in this context, is that it is the surface manifestation of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Water_table&quot; rel=&quot;noreferrer&quot;&gt;groundwater table&lt;/a&gt;. If you dig a well next to a body of water you’ll reach ground water at the same altitude as the river water surface. The gradient of the groundwater surface and the permeability of the material controls the direction and velocity of the flow. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, if more water enters a system than the surface can infiltrate, the surplus will flow as surface runoff, typical for wadis &lt;em&gt;(See picture)&lt;/em&gt; in desert areas. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/JWOl5.jpg&quot; alt=&quot;Wadi. Photograph taken by Mark A. Wilson, The College of Wooster&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, to answer your question. It depends on the local geology, but ground water will always flow from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Precipitation&quot; rel=&quot;noreferrer&quot;&gt;precipitation&lt;/a&gt; area to the oceans (or a lower point where it can evaporate or being pumped up). Ground water exists everywhere and the gradient of the hydrostatic pressure controls the direction of the flow. As viable rivers shows the ground water table, it is usually rather safe to assume that the ground water under the dry river flows more or less the same direction. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, ground water flow can be changed by e.g. pumping from irrigation wells. Imagine a flat lying river bed with a well upstream. When enough water is removed from the well and eventually evaporated, ground water will flow towards the well. The water don't 'remember', but follows the law of gravity. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2015-07-13T14:18:28.267" LastActivityDate="2015-07-13T14:18:28.267" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5151" PostTypeId="1" CreationDate="2015-07-08T13:28:46.347" Score="10" ViewCount="2578" Body="&lt;p&gt;In 2009, the oceanographic community decided to adopt the Thermodynamic Equation Of Seawater - 2010 (&lt;a href=&quot;http://www.teos-10.org/&quot;&gt;www.teos-10.org&lt;/a&gt;) as the standard to calculate the properties of seawater. As part of that, they changed from the conductivity-based salinity (Practical Salinity, PSS-78, as part of the EOS-80) to Absolute Salinity (mass fraction of salt in seawater). What are the main differences between the two standards? Where in the world ocean should we expect to see the biggest differences between the two? &lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2015-07-08T14:00:57.317" LastActivityDate="2015-07-10T14:53:32.237" Title="Differences between TEOS-10 and EOS-80 for salinity" Tags="|ocean|oceanography|salinity|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5152" PostTypeId="1" CreationDate="2015-07-08T13:38:26.777" Score="11" ViewCount="2574" Body="&lt;p&gt;The new standard for ocean temperature is the &quot;conservative temperature&quot;. It is based on a hypothetical adiabatic and isohaline change in pressure to the sea surface. Conservative temperature was adopted as the standard by the oceanographic community as part of the Thermodynamic Equation Of Seawater - 2010 (&lt;a href=&quot;http://www.teos-10.org/&quot;&gt;www.teos-10.org&lt;/a&gt;). The previous standard (EOS-80) was Potential Temperature. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the differences between potential and conservative temperatures? What are the benefits of using conservative temperature? Where should I expect the biggest departures between the two temperatures and why? &lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2019-01-28T20:35:31.650" Title="What are the benefits of using conservative temperature in oceanography?" Tags="|ocean|oceanography|temperature|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5154" PostTypeId="1" AcceptedAnswerId="5170" CreationDate="2015-07-09T02:23:34.257" Score="11" ViewCount="1252" Body="&lt;p&gt;In the formula for slant stacking (tau-p transform) a substitution &lt;code&gt;t=tau+d/v&lt;/code&gt; is made. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we consider the substitution as a vector equation then how can vector d/v have the same length as vector t given that in most surveys the number of data points for offset(d) is less than for time (t) .&lt;/p&gt;&#xA;" OwnerUserId="594" LastEditorUserId="725" LastEditDate="2015-07-09T05:54:01.420" LastActivityDate="2016-10-05T16:04:00.387" Title="Discrete Slant Stack on seismic data" Tags="|geophysics|seismology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5156" PostTypeId="2" ParentId="5148" CreationDate="2015-07-10T02:21:21.390" Score="9" Body="&lt;p&gt;To answer this question, I'll back up a bit and first talk about what happens to rain as it flow to streams then about what happens when streams dry up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When it rains, some of the rain hits the ground or trees/plants and is evaporated before it flows away from where it hits and before it sinks into the soil very far. Some enters the soil but is taken up by plant roots and &lt;em&gt;transpires&lt;/em&gt; back into the atmosphere. We don't need to worry about those components for this question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some of the rain flows down the ground surface, more or less as &lt;em&gt;sheet flow&lt;/em&gt; and eventually merges into little flow paths to the creek or river. That's called &lt;em&gt;runoff&lt;/em&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Typically, some rain will enter the ground and flow down to the &lt;em&gt;water table&lt;/em&gt;, which is the surface of the saturated &lt;em&gt;groundwater&lt;/em&gt;. By that I mean permanent water in the subsurface where all the void spaces in the rock or sediment are completely filled with water (there are some different definitions of groundwater that include the unsaturated zone but I'll keep them separate). Groundwater flows &lt;em&gt;downgradient&lt;/em&gt; under gravity towards a stream, river, lake, or the coast.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In between there is sort of a fuzzy situation where water flows in the unsaturated soils, moving downward and or sideways until it concentrates in a &lt;em&gt;perched aquifer&lt;/em&gt; or a seepage face at the stream. That water will discharge to the surface water system. Importantly, it typically reaches the surface water more quickly than the groundwater flow but slower than the runoff. Its often called &lt;em&gt;quickflow&lt;/em&gt;, &lt;em&gt;interflow&lt;/em&gt;, or &lt;em&gt;perched flow&lt;/em&gt;. Let's not worry about this too much - you can think of it as slow runoff or fast groundwater that kind of smears out the streamflow peaks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Streamflow, then, is mostly made up of these 3 components. Why do streams flow between rain storms? It does take runoff some time to reach the stream and flow downstream so it doesn't stop instantly but it goes away the fastest of the three. Quickflow will keep going a bit longer and depends a lot on the geology, soils, and topography. Simplistically, it will keep streams flowing longer than pure runoff would. Saturated groundwater is a slower process in terms of its discharge to a stream and, particularly for big rivers can keep them flowing year round. The first take-away message is the groundwater and surface water are interconnected - at least in the big picture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A couple of interesting things can happen to the groundwater-surface water connection. First, there might not be enough groundwater flow to keep it discharging to a stream, either seasonally like your creek or permanently in some places. If the stream still has water it can reverse the connection and lose water to the groundwater - a &lt;em&gt;losing stream&lt;/em&gt; instead of a &lt;em&gt;gaining stream&lt;/em&gt;. Without more rain or flow from upslope the stream will dry up. In some cases the groundwater level can drop faster than the stream drains into the sediments and the system can become &lt;em&gt;disconnected&lt;/em&gt;. The groundwater flow direction shifts so it is not towards the stream but towards a more regional discharge location. Since streams also flow down to the regional surface water system, the groundwater will often take a similar path but overall I don't think of it as an underground stream.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally though, things aren't always that straight-forward. One thing that often happens is that valleys fill up with sediments that are more permeable than surrounding sediments or rock formations and allow more flow. In that case the groundwater flow is mostly along the stream flow direction in the valleys and stream bed. It then looks similar to an underground river. That can happen when the river or creek is flowing or when it stops. The fancy word for it when the river is flowing (particularly when you are talking about pretty local scale effects) is &lt;em&gt;hyporheic&lt;/em&gt; flow - meaning flow below the river. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So that's probably more than you wanted to know, but for your creek it might go each year from pretty much all runoff, to gaining groundwater, to losing to the groundwater, to disconnected, to dry with some subsurface flow through the stream bed to more overall groundwater flow that doesn't see any influence from the stream location. But it depends on the weather, the sediments, how steep the land surface is, and perhaps some other complicating factors.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2015-07-10T02:21:21.390" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5157" PostTypeId="1" AcceptedAnswerId="5158" CreationDate="2015-07-10T12:11:05.660" Score="7" ViewCount="313" Body="&lt;p&gt;The SMH &lt;a href=&quot;http://www.smh.com.au/environment/weather/sydney-weather-polar-burst-to-bring-plunge-in-temperatures-snow-to-alps-20150709-gi88ak&quot; rel=&quot;noreferrer&quot;&gt;journalist writes&lt;/a&gt; about a cold snap hitting the East Coast of Australia in July 2015:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Proof of the big chill will be the extent of regions across Tasmania, Victoria and NSW experiencing zero temperatures, the Bureau of Meteorology said.&lt;/p&gt;&#xA;&lt;p&gt;A belt of low pressure systems is a fairly permanent feature of Antarctica. One of those lows - at a latitude of about 55-60 south - is currently to the south of Tasmania and further from the Antarctic coast than usual, Dr Trewin said.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;What would cause this low pressure zone to extend further from the Coast of the Antarctic than usual? Could it be a large chunk of ice melting?&lt;/p&gt;&#xA;&lt;p&gt;My question is: &lt;strong&gt;Are Southern Hemisphere 'Polar Blasts' caused by global warming?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="895" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-07-10T18:31:19.033" Title="Are Southern Hemisphere 'Polar Blasts' caused by global warming?" Tags="|meteorology|climate-change|temperature|severe-weather|" AnswerCount="2" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5158" PostTypeId="2" ParentId="5157" CreationDate="2015-07-10T13:26:32.213" Score="6" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/NG8FJ.gif&quot; alt=&quot;Southern Hemisphere Jet stream 10 July 2015 (C) squall.sfsu.edu/&quot;&gt;&#xA;Looking at the southern hemisphere polar jet, there is a large trough (meander) in the jet stream bringing cold air a long way north from the Antarctic to south eastern Australia at present. The relevance of the position and shape of the jet stream is thought to be important for keeping cold polar air in place above the antarctic/arctic, with a strong jet stream keeping cold air hemmed in above the poles while a weak jet stream meanders allowing cold waves/blasts to escape into the midlatitudes. &lt;a href=&quot;https://earthscience.stackexchange.com/questions/424/did-global-warming-cause-the-extreme-cold-2013-14-winter-in-north-america/427#427&quot;&gt;This previous Stack Exchange question&lt;/a&gt; sets out how the theory of arctic/polar amplification which is thought to affect the position and shape of the jet stream is being studied in connection to climate change (Generally it has been proposed that global warming will make the jet stream more wobbly/meandering, and so increase instances of cold weather in the mid latitudes).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Single weather events such as this are not caused by global warming, but it has been hypothesised that their frequency of occurrence may change due to warming, though as you can read in the linked stack exchange this theory is not universally accepted.&lt;/p&gt;&#xA;" OwnerUserId="140" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-07-10T18:31:19.033" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5159" PostTypeId="2" ParentId="5151" CreationDate="2015-07-10T14:53:32.237" Score="4" Body="&lt;p&gt;From my reading of the &lt;a href=&quot;http://www.teos-10.org/pubs/TEOS-10_Primer.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;primer&lt;/a&gt; and &lt;a href=&quot;http://www.teos-10.org/pubs/TEOS-10_Manual.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;manual&lt;/a&gt;, I would summarize the difference as follows. Practical salinity is calculated directly from the conductivity of seawater (which is what's most often measured by buoys, floats, and other autonomous systems) whereas absolute salinity is based on the density of the seawater. Practical salinity is essentially measuring the distribution of &lt;em&gt;ions&lt;/em&gt; in the seawater. Absolute salinity is based on the mass of &lt;em&gt;all&lt;/em&gt; non-H2O material, whether it's ions, gases, or solids. Relating salinity to mass, rather than conductivity, makes writing conservation equations much more straightforward; a dissolution of HCO$_3^-$ into H$^+$ and CO$_3^{2-}$ changes the practical salinity but not the absolute salinity. Basing salinity on mass also makes the thermodynamics much simpler, but I'll address that in your &lt;a href=&quot;https://earthscience.stackexchange.com/questions/5152/what-are-the-benefits-of-using-conservative-temperature-in-oceanography&quot;&gt;other question&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Differences between the practical and absolute salinities crop up where there are big differences in the composition of seawater, especially in its dissolved but non-ionic components. Page 14 of the manual (Fig 2) has some maps of what this looks like: Large deviations in the lower-salinity Pacific, and large deviations at depth where density and conductivity aren't so closely related. Absolute salinity can handle measurements of seawater composition in a way that practical salinity doesn't.&lt;/p&gt;&#xA;" OwnerUserId="1342" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-07-10T14:53:32.237" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5160" PostTypeId="2" ParentId="5152" CreationDate="2015-07-10T15:17:48.097" Score="5" Body="&lt;p&gt;The &lt;a href=&quot;http://www.teos-10.org/pubs/TEOS-10_Manual.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;TEOS-10 manual&lt;/a&gt;, page 26, says that the potential temperature is the temperature that a parcel of fluid conserving its Gibbs energy and absolute salinity would have if brought to the surface, or from an integral of the adiabatic lapse rate. The conservative temperature is not a true temperature, but a multiple of the enthalpy. It's really an energy that's been scaled to have units of temperature. The scale factor is the heat capacity of water in a standard state, since it's taken to be constant. In the potential temperature, the heat capacity is allowed to vary during ascent. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This distinction crops up a lot in meteorology, where the moist static enthalpy is conserved under adiabatic ascent, whereas other measures of temperature aren't conserved. I think the reason for the change is similar to why we would use enthalpy in meteorology, too. Suppose that the adiabatic changes in pressure and temperature also change the equilibrium coefficients of some reaction, say $\ce{CO2 + H2O -&amp;gt; H+ + HCO3-}$. This would change the absolute salinity, since it's splitting apart a water molecule into ions. The actual ascent can be adiabatic - there's no mixing with the surrounding water - but it's no longer isohaline. The enthalpy will still be conserved, though. This is why I think your questions (&lt;a href=&quot;https://earthscience.stackexchange.com/questions/5151/differences-between-teos-10-and-eos-80-for-salinity/5159#5159&quot;&gt;here's the other one&lt;/a&gt;) are related: using a mass-based salinity fits in much better with a thermodynamically-consistent formulation of the Equation of State, and using the enthalpy over the potential temperature is part of this complex salinity-temperature-entropy relationship.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The manual mentions that near the surface, the differences between potential and conserved temperature should be really small. The heat capacity chosen to scale the enthalpy is similar to that for surface water. You'd get the largest differences at depth and where the composition of seawater is much different (like with absolute salinity). The difference here is whether that composition is expected to change with temperature and pressure.&lt;/p&gt;&#xA;" OwnerUserId="1342" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-03-12T03:30:27.753" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5161" PostTypeId="2" ParentId="5157" CreationDate="2015-07-10T17:57:49.287" Score="4" Body="&lt;p&gt;In general, climate is the statistics of weather over a long period of time.  In general, an individual weather event cannot be attributed to global change / global warming.  An increase in the &lt;em&gt;frequency&lt;/em&gt; of such events could be attributed to climate change.  But considering how noisy weather and climate are, it takes a very long time series to measure an increase in frequency, in particular for rare events.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That being said, if an event occurs that is &lt;em&gt;extremely&lt;/em&gt; unlikely under the null hypothesis of a stationary climate, but only moderately unlikely under a changed or changing climate, one could consider that this event &lt;em&gt;likely&lt;/em&gt; means that climate has changed.  But one needs to be very careful with such an analysis, because even unlikely events do happen, and on a global scale, the probability that this year there is a one-in-a-million-years event &lt;em&gt;somewhere&lt;/em&gt; is far larger than one in a million.  And we'd still need to be sure that we understand the present climate correctly — we could be underestimating the likelihood of an event in the prior climate regime, in particular if we have no prior experience with those events.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to summarise: for a single event, we cannot say if this polar blast is caused by global warming.  If the frequency of those increases along with global warming, then we &lt;em&gt;may&lt;/em&gt; be able to establish a causal relationship.  Or not.&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2015-07-10T17:57:49.287" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5162" PostTypeId="1" AcceptedAnswerId="5166" CreationDate="2015-07-11T01:32:52.600" Score="16" ViewCount="4913" Body="&lt;p&gt;Lots of people comment that you have to use more sunscreen in Australia compared to European countries due to the hole in the ozone layer. (Even for roughly equivalent latitudes). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would cause this imbalance? It can't be gravity, since that comes from the centre of the earth. Perhaps magnetic poles could have an influence, but I don't understand how. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: &lt;strong&gt;Why is the Ozone Layer 'hole' more pronounced in the Southern Hemisphere?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="895" LastActivityDate="2015-07-11T03:06:53.690" Title="Why is the Ozone Layer 'hole' more pronounced in the Southern Hemisphere?" Tags="|atmosphere|ozone|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5163" PostTypeId="2" ParentId="5162" CreationDate="2015-07-11T02:10:45.763" Score="5" Body="&lt;p&gt;The south pole has a continent covering it, which allows the retention of relatively long and cold storms, compared to the North Pole.  The north pole is covered by water and is not an elevated land mass, so it is a bit warmer on average.  Polar stratospheric clouds have chemistry on the ice particles that leads to catalytic ozone depletion (mainly caused by human emissions of CFCs).  The colder it is... the more of this can occur.&lt;/p&gt;&#xA;&lt;p&gt;From &lt;a href=&quot;https://en.wikipedia.org/wiki/Ozone_depletion&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Ozone_depletion&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Reductions of up to 70% in the ozone column observed in the austral (southern hemispheric) spring over Antarctica and first reported in 1985 (Farman et al.) are continuing. Since the 1990s, Antarctic total column ozone in September and October continued to be 40–50% lower than pre-ozone-hole values.[1] In the Arctic, the amount lost is more variable year-to-year than in the Antarctic. The greatest Arctic declines, up to 30%, are in the winter and spring, when the stratosphere is coldest.&lt;/p&gt;&#xA;&lt;p&gt;Reactions that take place on polar stratospheric clouds (PSCs) play an important role in enhancing ozone depletion.[8] PSCs form more readily in the extreme cold of the Arctic and Antarctic stratosphere. This is why ozone holes first formed, and are deeper, over Antarctica.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-07-11T02:10:45.763" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5164" PostTypeId="2" ParentId="5162" CreationDate="2015-07-11T02:18:39.400" Score="7" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Polar_stratospheric_cloud&quot;&gt;Polar stratospheric clouds&lt;/a&gt; are the answer. These clouds contain solid nitric acid (mixed with water ice and sulfuric acid), and when they form they remove gaseous nitric acid from the air. This impacts the other chemical cycles in the stratosphere and leads to ozone depletion. &lt;a href=&quot;http://cires1.colorado.edu/jimenez/AtmChem/Chem5151_strat2.pdf&quot;&gt;This powerpoint&lt;/a&gt; is kinda long, but I think it explains the chemistry fairly well. It's written from a historical perspective, contrasting the different theories for ozone loss.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These kinds of clouds only occur at extremely low temperatures, though. You can see them sometimes in the Arctic, but not nearly as often as in the Antarctic. Oddly enough, this is caused (mostly) by there being more mountain ranges in the northern hemisphere. Mountain ranges can induce atmospheric waves that travel up into the stratosphere and perturb the stratospheric vortex. (The &lt;a href=&quot;https://en.wikipedia.org/wiki/Polar_vortex&quot;&gt;Wiki page&lt;/a&gt; image shows what a perturbed and unperturbed vortex look like.) Without that perturbation, the stratosphere can just keep cooling down by radiating to space all winter while there's no sunlight. This is why the Antarctic is so much colder than the Arctic, and why polar stratospheric clouds form there much more often.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So...The ozone hole is worse in the southern hemisphere because there are fewer mountain ranges there. Earth science is weird!&lt;/p&gt;&#xA;" OwnerUserId="1342" LastActivityDate="2015-07-11T02:18:39.400" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5165" PostTypeId="1" AcceptedAnswerId="5167" CreationDate="2015-07-11T02:30:43.347" Score="4" ViewCount="6300" Body="&lt;p&gt;Many people have observed that people 'tan faster' in the Southern Hemisphere, compared to equivalent latitudes in Europe. Some Australians even say the sun is 'less bright' on a European beach. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now is there some natural Earth-Science explanation for this - or do we go back to a climate-change explanation for this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: &lt;strong&gt;Is the difference in 'Summer tanning' in the Southern Hemisphere related to the Ozone hole or are there other factors?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="895" LastActivityDate="2015-07-11T04:02:21.863" Title="Is the difference in 'Summer tanning' in the Southern Hemisphere related to the Ozone hole or are there other factors?" Tags="|atmosphere|ozone|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5166" PostTypeId="2" ParentId="5162" CreationDate="2015-07-11T03:06:53.690" Score="9" Body="&lt;p&gt;Two significant factors that influence the size of the ozone hole over the southern pole are temperature and the polar vortex.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A number of sources confirm that the ozone hole increases in size when the temperature over Antarctica is colder. (&lt;a href=&quot;http://www.atmos-chem-phys.net/14/217/2014/acp-14-217-2014.pdf&quot;&gt;Parrondo et al&lt;/a&gt;, &lt;a href=&quot;http://www.theozonehole.com/2012ozonehole.htm&quot;&gt;The Ozone Hole&lt;/a&gt;, &lt;a href=&quot;http://www.shsu.edu/~chm_tgc/CHM442/PSC.html&quot;&gt;Sam Houston State University&lt;/a&gt;),&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The polar vortices that form over the northern and southern poles are different because the northern vortex forms over water that is surrounded by land, whereas in the southern hemisphere the situation the opposite; the vortex forms over land surrounded by water. Because of this, Antarctica &quot;is meteorologically isolated from air at higher latitudes during winter&quot;. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This physical condition forms an isolated air mass swirling over Antarctica called the south polar vortex. In the air of the polar vortex, the temperatures drop to very low levels in the stratosphere, below -80 degrees Celsius. At these temperatures, chemicals present in the stratosphere freeze out and form polar stratospheric clouds (PSCs). It is the chemical reactions that occur on the PSCs that result in the large decrease in ozone during each austral spring over Antarctica that we called the Antarctic ozone hole. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Chlorine and fluorine oxides, produced by stratospheric photolysis (sunlight induced decomposition) of Chlorofluorocarbons (CFCs) also contribute to the depletion of ozone. During the southern winter, Antarctica is predominately dark due to the lack of sunshine. With no sun light photolysis of CFCs does not occur. During the southern summer when Antarctica is continuously sunlit CFCs decompose, further reducing ozone levels within the polar vortex.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-07-11T03:06:53.690" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5167" PostTypeId="2" ParentId="5165" CreationDate="2015-07-11T03:53:37.070" Score="5" Body="&lt;p&gt;Tanning is the skin's response due to the dose of UV radiation that the person is exposed to &lt;a href=&quot;https://en.wikipedia.org/wiki/Sun_tanning&quot; rel=&quot;noreferrer&quot;&gt; [Wikipedia&lt;/a&gt;].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One major factor for the differences in tanning between the two hemispheres is that the Earth's orbit is not circular - and is at aphelion (furthest distance from the sun) during the Northern Hemisphere summer and is at perihelion (closest distance from the sun) during the Southern Hemisphere summer.  See the diagram below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/23Z7l.png&quot; alt=&quot;enter image description here&quot;&gt;&#xA;&lt;em&gt;Source: &lt;a href=&quot;http://spaceplace.nasa.gov/seasons/en/&quot; rel=&quot;noreferrer&quot;&gt;NASA&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hence, a greater amount of solar radiation reaches the Earth's surface during the southern hemisphere summer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the ozone 'hole', as can be seen in the image below, it only really affects Antarctica and surrounding oceanic waters to any great extent:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/fYUXs.jpg&quot; alt=&quot;enter image description here&quot;&gt;&#xA;&lt;em&gt;Source: &lt;a href=&quot;http://ozonewatch.gsfc.nasa.gov/facts/hole_SH.html&quot; rel=&quot;noreferrer&quot;&gt;NASA&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Taking Australia as an example (as you mentioned it in your question).&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the Australian Bureau of Meteorology FAQ about &lt;a href=&quot;http://www.bom.gov.au/uv/faq.shtml&quot; rel=&quot;noreferrer&quot;&gt;ultraviolet radiation&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Does the Antarctic Ozone Hole ever come over Australia?&lt;br&gt;&#xA;  No. The ozone hole has only ever been observed to be well south of the Australian mainland and Tasmania. In fact, during springtime, when the hole is in existence, ozone levels over southern Australian cities are at their highest.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;However, after the ozone hole has broken up parcels of ozone depleted&#xA;  air mixed with mid latitude air move northwards. These parcels can&#xA;  move over the southern part of Australia and cause a reduction in&#xA;  total ozone values.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Australia's SunSmart FAQ about &lt;a href=&quot;http://www.sunsmart.com.au/about/faqs#ultraviolet-radiation&quot; rel=&quot;noreferrer&quot;&gt;UV radiation&lt;/a&gt; sums it up nicely:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Why does Australia have high levels of UV radiation?&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Australia experiences some of the highest levels of UV radiation in&#xA;  the world because we are close to the equator and have a lot of clear&#xA;  blue-sky days. The Earth's orbit also takes countries in the southern&#xA;  hemisphere (Australia included) closer to the sun in their summertime&#xA;  than countries in the northern hemisphere during their summer.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user2872" LastEditorDisplayName="user2872" LastEditDate="2015-07-11T04:02:21.863" LastActivityDate="2015-07-11T04:02:21.863" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5169" PostTypeId="1" CreationDate="2015-07-11T15:41:32.943" Score="25" ViewCount="12109" Body="&lt;p&gt;The record for most rainfall in a single hour is 12 inches (30.5 cm), set in Holt, Missouri, in 1947. What is the maximum amount of rainfall that could theoretically occur in an hour?&lt;/p&gt;&#xA;" OwnerUserId="3157" LastEditorUserId="192" LastEditDate="2015-08-04T20:08:01.520" LastActivityDate="2022-01-08T03:31:14.210" Title="Is there an upper bound to the amount of rain that can fall in an hour?" Tags="|meteorology|rainfall|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="5170" PostTypeId="2" ParentId="5154" CreationDate="2015-07-13T03:02:00.013" Score="6" Body="&lt;p&gt;To be consistent with the references referred to in this post, I will re-write your equation of the $\tau-p$ transform as:&#xA;$t = \tau + px$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where $t$ is two-way time, $x$ is offset, $p$ is ray parameter ($\Delta x / \Delta t$ or $\sin(\theta) / velocity$), $\tau$ is the intercept time when $p=0$ (Yilmaz, 2001). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There seem to be at least two methods for overcoming the finite aperture, or limited offset and ray parameter range, problem when transforming from time-offset ($t-x$) domain to $\tau-p$ domain:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Sample ray parameter $p$ such $np = nx$; i.e. number of ray parameter samples equals number of offset samples (Yilmaz, 2001).&lt;/li&gt;&#xA;&lt;li&gt;Formulate the the computation of the transform as a least-squares estimation problem (Kostov, 1990; Thorson and Claerbout, 1985). &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Kostov, C., 1990. Multi-channel seismic experiment with a drill-bit source. Phd Thesis, Standford University. &lt;a href=&quot;http://sepwww.stanford.edu/data/media/public/oldreports/sep63/63_06.pdf&quot; rel=&quot;nofollow&quot;&gt;See Appendix C for details on least-squares solution.&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thorson, J. and Claerbout, J., 1985. Velocity-stack and slant-stack stochastic inversion. Geophysics, Vol. 50, N. 12, P. 2727-2741.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yilmaz, Öz (2001). Seismic data analysis. Society of Exploration Geophysicists. ISBN 1-56080-094-1.  &lt;a href=&quot;http://wiki.seg.org/wiki/Slant-stack_parameters&quot; rel=&quot;nofollow&quot;&gt;See SEG Wiki page on the problem.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="777" LastEditorUserId="20" LastEditDate="2016-02-20T00:07:25.657" LastActivityDate="2016-02-20T00:07:25.657" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5171" PostTypeId="1" CreationDate="2015-07-13T05:32:18.910" Score="10" ViewCount="1411" Body="&lt;p&gt;Seismic inversion methods help to visualize the subsurface layers of the earth in terms of petrophysical properties (e.g. impedance). Still some geophysicists use the final inverted impedance model in company with various seismic attributes (like amplitude envelope, instantaneous frequency, and phase) to predict lithology or paleogeographic features.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If seismic inversion transforms the reflection amplitude into acoustic impedance (lithology) than why can't it be used to predict the lithology independently?&lt;/p&gt;&#xA;" OwnerUserId="2662" LastEditorUserId="28050" LastEditDate="2015-11-17T12:47:57.783" LastActivityDate="2017-03-11T03:43:14.983" Title="What are the challenges in predicting lithology directly from acoustic impedance?" Tags="|geophysics|geology|wave-modeling|paleogeography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5172" PostTypeId="1" CreationDate="2015-07-13T08:03:15.140" Score="10" ViewCount="421" Body="&lt;p&gt;I am currently reading this paper on digital filters and their relevance to meteorological models &lt;a href=&quot;http://mathsci.ucd.ie/~plynch/Publications/ASI-DFI.pdf&quot; rel=&quot;nofollow&quot;&gt;Digital Filter Initialization &lt;/a&gt;. My question relates to this following text - &quot;The requirement to modify meteorological analysis to avoid spurious high frequency oscillations has been known from the beginning of numerical weather prediction&quot;. Is it possible to get a mathematical illustration of how this problem originally arises(i.e. spurious high frequency oscillations) in numerical weather prediction ? &#xA;I am not sure whether I can edit this question but I would like to restrict the domain of the question to high frequency oscillations arising in  high resolution simulations and one that involves a LES. Numerically I have four nested grids - my country, a state within that and a district within that state and then a small valley inside that district. My question relates to the high frequency oscillations inside the innermost grid. Let us assume model independence for this question.&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorUserId="192" LastEditDate="2015-07-14T15:38:14.713" LastActivityDate="2015-08-05T22:48:21.143" Title="The origin of spurious high frequency waves in numerical weather prediction" Tags="|meteorology|numerical-modelling|nwp|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5173" PostTypeId="1" CreationDate="2015-07-13T19:14:21.080" Score="10" ViewCount="252" Body="&lt;p&gt;I am working through this problem on my own as well, but am feeling that some perspective is in order. So, ignoring the obvious effects where precipitation will wash stuff out of the air, and blocking sunlight will prevent chemical reactions from occurring that depend on photon energy - in fact, we'll just assume a chemically inert atmosphere with no significant deposition and emission of pollutants. We'll also go ahead and use the most common height and shape-based cloud type categorization system (&lt;a href=&quot;http://scied.ucar.edu/webweather/clouds/cloud-types&quot; rel=&quot;nofollow&quot;&gt;http://scied.ucar.edu/webweather/clouds/cloud-types&lt;/a&gt;). Also, to simplify, lets generally assume particulate pollution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How does the presence of a cloud impact pollutant levels in the air underneath it and how does this vary by cloud type?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An ideal answer will consider at least one of the below:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Synoptic scale determinants of cloud type such as pressure systems&lt;/li&gt;&#xA;&lt;li&gt;Thermodynamic changes in stability/mixing and/or boundary layer height&lt;/li&gt;&#xA;&lt;li&gt;Humidity - can include quibbling over whether the meaning of pollutant levels means measurement of dry mass, visibility reduction, or measurement under ground conditions (But, unless you want to get into this mess, lets assume dry mass).&lt;/li&gt;&#xA;&lt;li&gt;Cloud height (low, middle, high)&lt;/li&gt;&#xA;&lt;li&gt;Cloud shape (stratus, cumulus, nimbus, cirrus, etc.)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="2871" LastEditorUserId="543" LastEditDate="2015-07-22T00:31:18.533" LastActivityDate="2015-07-22T00:31:18.533" Title="How do the various types of clouds affect the atmosphere below them in a polluted environment?" Tags="|meteorology|clouds|air-pollution|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5174" PostTypeId="1" AcceptedAnswerId="12594" CreationDate="2015-07-13T21:24:15.783" Score="7" ViewCount="397" Body="&lt;p&gt;I'm trying to solve the following problem.&#xA;The sea level in the past was 200 m higher than today. The seawater became in isostatic equilibrium with the ocean basin. what is the increase in the depth $x$ of the ocean basins? Water density is $\rho_w = 1000\ kg\ m^{-3}$, and mantle density is $3300\ kg\ m^{-3}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using the compensation column, I reach:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;x = (\rho_w * 200\ m)/ 3300 = 60.60\ m&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;but normally I expected to find 290 m.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can someone explain to me what's wrong?&lt;/p&gt;&#xA;" OwnerUserId="3161" LastEditorUserId="192" LastEditDate="2015-07-13T21:40:18.207" LastActivityDate="2018-01-31T15:47:04.613" Title="How to calculate hydrostatic equilibrium?" Tags="|geodynamics|homework|isostasy|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="5175" PostTypeId="2" ParentId="5172" CreationDate="2015-07-13T21:58:07.517" Score="2" Body="&lt;p&gt;I don't have a mathematical illustration at the moment (though I might edit this answer if I come across something in my notes). But the basic problem is sound waves. If you make a numerical model of the full Navier-Stokes equations, that model has to allow sound waves to propagate. That implies that the time step used has to be incredibly short -- under 5 minutes for sure for a grid size of 100 km, and preferably much shorter than that. So sound waves are fast-moving, high frequency, and don't really contribute to weather. That's why weather prediction models tend to use the &lt;a href=&quot;https://en.wikipedia.org/wiki/Primitive_equations&quot; rel=&quot;nofollow&quot;&gt;primitive equations&lt;/a&gt;: these equations are very similar to the Navier-Stokes, but sound waves aren't solutions to these equations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hopefully that's a start. Feel free to ask for a clarification on how this filtering is done in practice. Like I said, I'll look through my notes for something, I remember doing a problem set involving this.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Edit: &lt;a href=&quot;http://kiwi.atmos.colostate.edu/group/dave/pdf/AneBous.pdf&quot; rel=&quot;nofollow&quot;&gt;Here&lt;/a&gt; are some notes from David Randall on the anelastic and Boussinesq approximations. &lt;a href=&quot;http://snowball.millersville.edu/~adecaria/ESCI342/esci342_lesson07_continuity_equation.pdf&quot; rel=&quot;nofollow&quot;&gt;These notes&lt;/a&gt; are in more of a classroom format, but at the end they derive the link between the continuity equation and sound waves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Briefly, sound waves arise from variations in density that are independent of variations in enthalpy/temperature. The continuity equation in general is $ \frac{\partial \rho}{\partial t} + \nabla\cdot (\rho \vec{u}) = 0 $ in which density variations can be accompanied by contraction and expansion of the fluid. The anelastic equations filter out sound waves by replacing this dynamic equation with a diagnostic one, removing the time derivative: $ \nabla\cdot(\rho_0 \vec{u}) = 0 $ where $\rho_0$ is a background density profile. No more time derivative for density means no more expansion and contraction &lt;em&gt;except&lt;/em&gt; under changes in enthalpy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is how sound waves are filtered out. I realize that I didn't read the question closely enough, though. If you're working with an LES, at that fine of a spatial resolution, you're probably 1) already using the anelastic equations, and 2) properly resolving a lot of the high-frequency oscillations anyway. As @milancurcic mentioned, gravity waves become an issue as the next-highest frequency waves. &lt;a href=&quot;http://mafija.fmf.uni-lj.si/seminar/files/2011_2012/Normal_modes.pdf&quot; rel=&quot;nofollow&quot;&gt;These notes&lt;/a&gt; go through the problem of gravity waves in a shallow-water model, and &lt;a href=&quot;http://link.springer.com/article/10.1007%2FBF01042186&quot; rel=&quot;nofollow&quot;&gt;this article&lt;/a&gt; (behind a paywall) shows how a good choice of initialization can help eliminate those waves.&lt;/p&gt;&#xA;" OwnerUserId="1342" LastEditorUserId="1342" LastEditDate="2015-07-15T12:36:14.020" LastActivityDate="2015-07-15T12:36:14.020" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5176" PostTypeId="1" AcceptedAnswerId="6601" CreationDate="2015-07-14T01:28:12.803" Score="8" ViewCount="85" Body="&lt;p&gt;What kind of mineralogy results when a serpentinite is reworked during high-T or UHT metamorphism? I am envisaging a possible scenario where an obducted ophiolite terrane is buried and metamorphised within thickened orogen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since seprentinite is hydrated/altered mafic or ultramafic rock, I would assume dehydration would be the first pathway. With further heating are serpentinites likely to yield melt? Could they end up as a 'normal' mafic granulite? Are there mineralogical or geochemical characteristics that could be used to identify a mafic granulite that started out life as a serpentinite?&lt;/p&gt;&#xA;" OwnerUserId="2563" LastActivityDate="2015-09-26T14:21:43.583" Title="Identifying serpentinite reworked during high-T metamorphism" Tags="|geochemistry|petrology|subduction|metamorphism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5177" PostTypeId="2" ParentId="4399" CreationDate="2015-07-14T05:18:23.897" Score="3" Body="&lt;p&gt;I am going to have a different perspective on this question. In relation to this incident - &lt;a href=&quot;https://en.wikipedia.org/wiki/2013_North_India_floods&quot; rel=&quot;nofollow&quot;&gt;Kedarnath Floods&lt;/a&gt; and  from this paper - &lt;a href=&quot;http://www.currentscience.ac.in/Volumes/105/10/1351.pdf&quot; rel=&quot;nofollow&quot;&gt;Cloud Burst in Kedarnath&lt;/a&gt; no TRMM PR passes were available for the 16th of June and only two passes were available for the 15th - 17th June period over Uttarakhand. This raises the question whether TRMM can be indeed be used to study synoptic systems as large spatial and temporal variations in rainfall require hourly satellite data to measure the impact of heavy rainfall. Hence the authors are using an indirect estimate from IR radiance derived from Meteosat-7 geostationary satellite observations. The broad gist of these findings  is that colder clouds in IR images are more likely to precipitate than warmer clouds as the cold clouds have higher cloud tops than warmer ones. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastActivityDate="2015-07-14T05:18:23.897" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5178" PostTypeId="1" AcceptedAnswerId="5249" CreationDate="2015-07-14T10:11:30.863" Score="11" ViewCount="492" Body="&lt;p&gt;There are plenty of choices in models in so far as choice of vertical coordinate is concerned for meteorological models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Five that I know of:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The sigma coordinate system - &lt;a href=&quot;https://en.wikipedia.org/wiki/Sigma_coordinate_system&quot; rel=&quot;nofollow&quot;&gt;Hybrid coordinate system&lt;/a&gt;(used by ECMWF);&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Terrain following pressure as vertical coordinate that is used by WRF &lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/docs/user_guide_V3/users_guide_chap5.htm&quot; rel=&quot;nofollow&quot;&gt;WRF Vertical Coordinate&lt;/a&gt;;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The system used in &lt;a href=&quot;http://www2.mmm.ucar.edu/people/bryan/cm1/cm1_equations.pdf&quot; rel=&quot;nofollow&quot;&gt;CM1&lt;/a&gt; which is Cartesian coordinate (that leads to metric terms);&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Step-mountain coordinate used in the &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0493%281990%29118%3C1429%3ATSMCPP%3E2.0.CO%3B2&quot; rel=&quot;nofollow&quot;&gt;Eta&lt;/a&gt; model, which was NCEP's operational regional model (NAM) from 1993 to 2006.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Gal-Chen and Somerville vertical coordinate &lt;a href=&quot;http://mesonh.aero.obs-mip.fr/mesonh/dir_doc/book1_07avr2000/node36.html&quot; rel=&quot;nofollow&quot;&gt;Gal-Chen Somerville vertical coordinate&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;How applicable are these different vertical coordinate systems in complex topography, especially in mountainous areas?&lt;br&gt;&#xA;Is there a case that one can make for a different type of vertical coordinate or can these existing vertical coordinate systems adequately reproduce meteorological measurements and observed phenomena? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Phrased differently: What sort of vertical coordinate leads to ease of implementation as well as adequate portrayal of weather events (lee troughs, pressure gradient force, etc) in mountains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please ignore whether such a coordinate system has currently been implemented by any model, but specify what an &quot;ideal&quot; vertical coordinate should be for complex topography. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2015-10-06T09:04:08.027" LastActivityDate="2015-10-06T09:04:08.027" Title="Optimal vertical coordinate for complex topography" Tags="|meteorology|atmosphere|numerical-modelling|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5179" PostTypeId="2" ParentId="5154" CreationDate="2015-07-14T14:36:15.283" Score="7" Body="&lt;p&gt;&lt;strong&gt;The $\tau$–$p$ time domain $t$ is a function of offset $d$, so the result is an array of size $n_t \times n_d$, where $n$ is the number of samples.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The inputs are a vector $\tau$ of travel time at zero offset, or $t(0)$, an array $p$ of &lt;a href=&quot;http://wiki.seg.org/wiki/Dictionary:Raypath_parameter&quot; rel=&quot;nofollow noreferrer&quot;&gt;ray parameter&lt;/a&gt;, which is in turn a function of velocity $V$ and angle, and a vector $d$ (usually called $x$) of offset.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's an example of some visualizations of the $\tau$–$p$ domain from &lt;a href=&quot;http://www.ahay.org/RSF/book/milano/taupvel/paper_html/&quot; rel=&quot;nofollow noreferrer&quot;&gt;a paper&lt;/a&gt; by Sergey Fomel; they might help explain what I mean by an 'array' — you can think of them as images:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/fxLZ1.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The resulting travel-time $t(d)$ is an array of size $n_t \times n_d$, where $n$ is the number of samples. For a &lt;em&gt;given&lt;/em&gt; offset at a &lt;em&gt;given&lt;/em&gt; time sample, the result is a scalar — a single value of $t$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By the way, &lt;strong&gt;stevej&lt;/strong&gt;'s answer is a great explanation of how exactly to calculate the ray parameter term, given limited information. Do follow that link to Yilmaz, and maybe also read &lt;a href=&quot;http://wiki.seg.org/wiki/The_radon_transform&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Radon transform article&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2016-10-05T16:04:00.387" LastActivityDate="2016-10-05T16:04:00.387" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5181" PostTypeId="1" AcceptedAnswerId="5184" CreationDate="2015-07-14T15:15:09.687" Score="33" ViewCount="12833" Body="&lt;p&gt;I took a tour of a cave in northern California last weekend. The tour guide asked us, &quot;&lt;em&gt;If an earthquake occurred, what would we feel in here?&lt;/em&gt;&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My answer was, &quot;fear,&quot; but she said we would feel nothing - that earthquakes are not felt underground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although I did not contest her assertion, I have my doubts about it - after all, don't earthquakes normally have their epicenter underground (well, &lt;em&gt;all the time&lt;/em&gt;, I reckon, as they can't emanate from the air)? And if an earthquake happened to erupt from within a cave[rn], wouldn't it most definitely be felt there?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would think one might even end up with a stalagtite stuck in his noggin.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;UPDATE&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;And, if I'm right (that there could be a whole lotta shakin' goin' on while on a journey to the centre of the earth), has anybody lived to tell the tale and really done it (told the tale)? A first-hand account could be riveting.&lt;/p&gt;&#xA;" OwnerUserId="3166" LastEditorDisplayName="user12525" LastEditDate="2019-04-17T10:23:35.077" LastActivityDate="2024-02-11T06:36:24.457" Title="Is it true that earthquakes are not felt in a cave?" Tags="|geology|geophysics|earthquakes|seismology|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="5182" PostTypeId="2" ParentId="5181" CreationDate="2015-07-14T16:58:13.403" Score="15" Body="&lt;p&gt;Googling leads to a very old document: &lt;a href=&quot;http://www.geo.arizona.edu/gsat/1887eq/historical/Stanton_1918_BSSA.pdf&quot; rel=&quot;noreferrer&quot;&gt;EFFECTS OF AN EARTHQUAKE IN A MINE AT TOMBSTONE, ARIZONA&lt;/a&gt; stating that in many cases, mine workers did not notice earthquakes which were felt above ground. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A newer book, &lt;a href=&quot;http://link.springer.com/chapter/10.1007%2F3-540-28500-8_18&quot; rel=&quot;noreferrer&quot;&gt;Earthquake effects on tunnels&lt;/a&gt;, check the &quot;Look Inside&quot; option for the introduction) confirms this. According to this source, a possible reason is that overground structures are less constrained in their movement while inside solid rock, the displacement cause by the earthquake is much smaller. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apparently your guide was right.&lt;/p&gt;&#xA;" OwnerUserId="681" LastEditorUserId="6093" LastEditDate="2016-09-27T12:13:22.020" LastActivityDate="2016-09-27T12:13:22.020" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5184" PostTypeId="2" ParentId="5181" CreationDate="2015-07-14T18:22:06.880" Score="26" Body="&lt;p&gt;Ground motion results due to passage of elastic waves. Now there are different kinds of waves, e.g., P waves, S waves, surface waves, etc. Most of the shaking (and therefore damage) is caused by surface waves. So if you are in a deep cave or mine then the amount of shaking you might experience can be much lower than on the surface. This of course assumes that the mine or cave is not right on the fault, but some distance (10s of km) away.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Having said that, there are some situations (based on the type of earthquake and local geology) in which waves can interfere constructively to cause significant shaking even at large depths, but this only happens in certain areas and not everywhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In many ways elastic wave propagation is similar to acoustic or water waves. Imagine a small explosive source in a lake/pond, let's say 50&amp;nbsp;m underwater. After the explosion there will be more 'shaking' on the surface, but not much underwater unless you're extremely close to the explosive source.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2015-07-21T01:12:18.983" LastActivityDate="2015-07-21T01:12:18.983" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="5185" PostTypeId="2" ParentId="5181" CreationDate="2015-07-14T18:52:30.103" Score="17" Body="&lt;p&gt;There are three main types of waves produced during an earthquake: P, S, and L waves, which stands for Primary, Secondary, and Love. (There was a mnemonic I read many years ago that went P=pressure, S=Shear, and L=Long.) The P and S waves are body waves. That is, they propagate inside the earth.  The P wave is basically a sound wave; as the mnemonic goes, a pressure wave.  The S wave is a shear wave and is perpendicular to the direction of fault slip.  The L wave, which has the highest amplitude is a surface wave and, as such, propagates along the surface, not inside.&lt;br&gt;&lt;br&gt;If you were inside a cave when a nearby earthquake occurred, you would not feel the L waves, since they propagate along the surface. Whether or not you would feel the P and S waves would depend mainly on two things: the magnitude of the original earthquake and the type of fault that produced it. If the fault were a thrust fault, the S wave would be up and down, which a standing person probably wouldn't feel unless the earthquake was quite large (&gt;5.5?).  However, if the earthquake were along a strike-slip fault, the S waves would be side to side, which a standing person would likely feel.&lt;br&gt;(I realize this answer duplicates some of that given by @stali, but I was already typing this when I saw that answer come across, and I thought I had some additional thoughts in this answer.  Sorry for the duplication.)&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2015-07-14T18:52:30.103" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5188" PostTypeId="2" ParentId="2283" CreationDate="2015-07-15T13:48:49.430" Score="8" Body="&lt;p&gt;This statement is known as the Wallace-Bott hypothesis. It is mostly valid for reactivated faults rather than fresh rocks(where cohesion comes into play). It says that the slip in a fault plane will occur along the direction of maximum shear stress. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So we have a stress vector acting on a fault plane(the direction given by the direction of force), it has two components-the normal component and the shear component. The normal component is responsible for opposing the slip as frictional force is proportional to the normal. And the shear force will be responsible for the slip to occur. This direction of shear stress is the direction of maximum shear stress and is dictated by the stress vector. (Note that it can have several components in the fault plane none of which will be maximum). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just think on the lines of high school physics involving friction, and it'll be easier to understand.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding Coulomb's criterion, although it gives an equation which relates shear strength, normal stress, cohesion in rocks and the angle of internal friction(You can google the equation), a research paper by Byerlee(1978) suggests that it is reasonable to take the shear stress/normal stress ratio as a fixed high value(around 0.85) for geologically realistic condition.&lt;/p&gt;&#xA;" OwnerUserId="3164" LastEditorUserId="3164" LastEditDate="2015-07-29T04:29:12.733" LastActivityDate="2015-07-29T04:29:12.733" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5189" PostTypeId="1" AcceptedAnswerId="5190" CreationDate="2015-07-15T20:50:49.920" Score="12" ViewCount="1455" Body="&lt;p&gt;On a meandering bit of research through Wikipedia, I was looking at the &#xA;&lt;a href=&quot;https://maps.google.com/maps?ll=39.8,-72.666667&amp;amp;q=39.8,-72.666667&amp;amp;hl=en&amp;amp;t=h&amp;amp;z=8&quot;&gt;Google Maps location of Texas Tower 4&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;South-east of that location there is what looks like a river valley under the ocean. If you follow it back to the land it is obviously the Hudson river.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my question(s) is: when was this 'valley' formed? Is the current of the Hudson river eroding this valley now, or was it eroded during a previous ice age? How old would this valley be?&lt;/p&gt;&#xA;" OwnerUserId="3178" LastActivityDate="2015-07-16T01:20:10.707" Title="Undersea riverbeds?" Tags="|ocean|geology|rivers|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5190" PostTypeId="2" ParentId="5189" CreationDate="2015-07-15T21:20:46.457" Score="12" Body="&lt;p&gt;There are two features that need to be distinguish here: one is the &lt;a href=&quot;http://pubs.usgs.gov/of/2004/1441/index.html&quot; rel=&quot;noreferrer&quot;&gt;Hudson Submarine Canyon&lt;/a&gt; on the continental slope, which starts at around 100 m and connects to the deep basin; and the &lt;a href=&quot;http://pubs.usgs.gov/of/2003/of03-372/index.html&quot; rel=&quot;noreferrer&quot;&gt;Hudson Shelf Valley&lt;/a&gt; on the continental shelf, which is much shallower (20-100m).&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/TrPNN.jpg&quot; alt=&quot;Hudson Shelf Valley&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;Assuming the question is about the Shelf Valley, &lt;a href=&quot;http://pubs.usgs.gov/of/2003/of03-372/html/discussion.html&quot; rel=&quot;noreferrer&quot;&gt;Butman et al. (2003)&lt;/a&gt; provided a thorough explanation of the origin and features of the valley. Here is their discussion:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The 150-km-long Hudson Shelf Valley, the largest physiographic feature on the mid-Atlantic continental shelf, bisects the New York Bight region (sheet 1 figure 1, and sheet 2, figure 6 and figure 7). The Valley is the submerged seaward extension of the ancestral Hudson River drainage system that, unlike other valleys on the Atlantic shelf, has not been filled with sediment. The valley head is located in a broad shallow basin (Christiansen Basin) and extends offshore 5-40 m below the shelf surface to a seaward terminus at a shelf-edge delta (Ewing and others, 1963; Emery and Uchupi, 1972; Uchupi and others, 2001).&lt;/p&gt;&#xA;&lt;p&gt;The ancestral Hudson River is hypothesized to have begun to develop in the Late Cretaceous when post-Atlantic rifting caused continued uplift and tilting of the margin, resulting in landward erosion and marginal seaward growth that continued into the Tertiary (Weiss, 1974). The Hudson Shelf Valley is thought to have been repeatedly downcut during periods of Pleistocene marine regression (Suter and others, 1949; Weiss, 1974). This downcutting possibly was amplified by the proposed catastrophic drainage of late Wisconsinan glacial lakes 12,000 - 14,000 yr BP (Newman and others, 1969; Uchupi and others, 2001). At this time, the shoreline was located approximately at the 60 m isobath (Thieler and others, 1999). At 12,000 - 14,000 yr BP, the large glacial lakes north of the New York Bight are thought to have breached the moraine front at the Verrazano Narrows and other locations in New Jersey and New York (Newman and others, 1969; Soren, 1971; Lovegreen, 1974). Boring data at the Verrazano Narrows indicate that more than 100 m of Pleistocene and Cretaceous sedimentary material was eroded as a result of this breaching event(s), along with most of the lacustrine sediment deposited during the previous 8,000 yr (Newman and others, 1969). Uchupi and others (2001) propose that late Wisconsin erosion of the Hudson Shelf Valley and deposition of sediment lobes (figure 1) on the outer shelf were a consequence of this catastrophic drainage.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="111" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-07-15T21:20:46.457" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5191" PostTypeId="2" ParentId="5189" CreationDate="2015-07-15T22:23:26.890" Score="5" Body="&lt;p&gt;OK, answering my own question(s), looking at the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hudson_Canyon&quot; rel=&quot;nofollow&quot;&gt;Wikipedia article on the Hudson Canyon&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The canyon was formed during the last Ice Age, over 10,000 years ago, when the sea level was about 400 feet (120 m) lower and the mouth of the Hudson River was near the edge of the continental shelf, about 100 miles (160 km) east of its present site.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And in terms of erosion:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;As silt, sand and mud are carried down the Hudson River, they flow into the canyon and out into the deep sea.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Tidal currents sweep up and down the channel; and on occasion, during big storms, cold ocean water is pushed up the Hudson Canyon to spread out on the shelf. Thus the Hudson Canyon continues to be cut by traveling sediments.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Anyone else have any interesting information about this Canyon?&lt;/p&gt;&#xA;" OwnerUserId="3178" LastEditorUserId="3178" LastEditDate="2015-07-16T01:20:10.707" LastActivityDate="2015-07-16T01:20:10.707" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5192" PostTypeId="2" ParentId="5171" CreationDate="2015-07-16T09:27:21.630" Score="10" Body="&lt;p&gt;Yes, lithology interpretation/classification directly from seismic inversion products is something people do.  I've seen it work very well in oil and  gas exploration and development of fields. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I personally think that there are two main challenges involved in predicting lithology from seismic inversion impedances. It would be a bit of a cop out to say that the whole inversion and lithology prediction process is challenging, so I won't, even though it is. So, assuming that you achieve good inversion results, by which I mean that your inversion synthetics match input seismic angle stacks and your inversion products (estimated elastic properties) match calibration points (upscaled well logs), I think that the challenges are the uncertainties associated with the:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;ability to discriminate rock types in study area, and&lt;/li&gt;&#xA;&lt;li&gt;low-frequency model&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Below I go into a &lt;em&gt;little&lt;/em&gt; more detail regarding these two factors. Just remember that I'm talking about lithology prediction from an absolute inversion. Also, I will talk about &quot;elastic properties&quot; a lot, by which I mean the P-impedance, S-impedance and density, or their derivatives like Lambda, Mu and Poisson's ratio if you're that way inclined. &lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Discrimination of rock types&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Before you attempt to predict lithologies from seismic inversion results, you need to know the expected elastic properties of the rocks in your study area. If the various rock types in your study area have the exact same elastic properties, distinguishing them from inversion products is going to be impossible, no matter how good your inversion is. To make a good lithology prediction you need to know the elastic properties of the measured or predicted rocks in your study area. If the rocks have similar (e.g. overlapping) rock properties you need to account for this uncertainty in your lithology prediction. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, say you are targeting gas and the predicted reservoir is sandstone. Does a gas filled sand have different elastic properties to a brine filled sand? What about from the sealing shale? What are the expected range of elastic properties for these rocks? By doing forward modelling experiments (e.g. Gassman fluid substitution and/or lithology mixing) you could answer questions that address risk-cases like: what are the expected elastic properties of a low saturation gas sand or a high porosity brine sand? If high porosity brine sands and gas-sands have similar/overlapping elastic properties and I end up predicting a gas-sand from my inversion, what is the probability that the gas-sand is 'real'? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/MIDch.gif&quot; alt=&quot;Vp versus Vp/Vs - from CREWES&quot;&gt;&#xA;(&lt;a href=&quot;https://www.crewes.org/ResearchLinks/Converted_Waves/Page3.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The above image shows the elastic properties for three lithologies: sandstone, shale and limestone, in terms of P-wave velocity** (Vp) and the ratio of P- to S- velocity (Vp/Vs). Provided your inversion results are accurate, these lithologies would be distinguishable because their property populations do not overlap. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mean P-wave velocity (Vp) for the limestone is approximately 5800 m/s. But what if the mean Vp was 4000 m/s? The limestone population would then overlap with the shale, meaning that it would be difficult to discriminate between the two lithologies from your inversion results with great confidence. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A thorough rock physics study is necessary before attempting any seismic inversion project to understand the elastic properties of your rocks and to ensure that your target rocks are distinguishable. If your rocks have sufficiently different elastic properties then lithology prediction from seismic inversion is feasible.  You can use your rock physics study to define how your lithologies can be classified from the inversion results (e.g. depth dependent probability density functions of P-impedance versus Vp/Vs for each lithology/fluid type). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;** Vp can only be estimated from seismic inversion if you also get a good density result, which is uncommon. I'd prefer it if this graph showed P-impedance (Vp * density), but beggars can't be choosers. &lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Low-frequency model&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;So, you know the elastic properties of the rocks in your study area and you know that they can be theoretically discriminated, and you want to predict lithologies from seismic inversion results? I think that the next challenge in lithology prediction are the uncertainties associated with the low-frequency model, because the low-frequency model: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;determines the absolute value of estimated elastic properties&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;so has a very big influence on the predicted lithology&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;is built by interpolating/extrapolating sparse data (e.g. well logs or rock physics trends)&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;i.e. a lot of the spatial variation of the low-frequency model is not measured&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;A low-frequency model is used to fill in the low-frequency elastic property gap not measured by seismic data, and allow absolute elastic properties to be estimated. For conventional marine seismic with a bandwidth of, say, 10-60Hz, the low-frequency model will provide the inversion with elastic properties of the study area between 0-10Hz (see picture below). What kind of geological information is captured within this low-frequency range? Large scale geological changes, like compaction trends, or the elastic property changes associated with low-order sequence stratigraphy cycles. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/JVBty.png&quot; alt=&quot;Frequencies range of seismic, wells and low-frequency model&quot;&gt;&#xA;(&lt;a href=&quot;http://petrologic.dmt.de/services/post-stack-inversion.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Without a low-frequency model, inversion can only provide the relative impedances of two layers; this is called a relative inversion. Inversion with a low-frequency model is called an absolute inversion, and it seeks to estimate the total elastic property of the layer, independent of impedance of above/below layers. If you get the low-frequency model wrong, your absolute elastic properties will also be wrong and therefore you will predict incorrect lithologies. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A low-frequency model can be built by extrapolating low-pass filtered well logs (P- and S-sonic and density), rock physics trends, etc throughout the study area, creating a 3D distribution of elastic properties. How can you be sure that you have a good low-frequency model?  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Blind well testing can give you confidence in your model. &lt;/li&gt;&#xA;&lt;li&gt;Use a robust method for extrapolating your well logs or rock physics trends. &lt;/li&gt;&#xA;&lt;li&gt;Even better would be to improve the low-frequencies of your seismic data through deghosting, to reduce the influence of the low-frequency model on your final interpretation.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h2&gt;Final thoughts&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;You can create different criteria for classifying lithologies, run an absolute inversion and predict lithology fairly easily these days. But if you don't have confidence in your ability to discriminate between different rock types or you're not sure if your estimated absolute elastic properties are correct, you cannot be sure that the lithologies you have predicted are useful. So what to do? Firstly you need to do a really good rock physics study first to understand the elastic properties of the rocks, and rocks you predict to be present, in your study area. Secondly put in a lot of effort to making sure you have a robust low-frequency model. &lt;/p&gt;&#xA;" OwnerUserId="777" LastEditorUserId="725" LastEditDate="2017-03-11T03:43:14.983" LastActivityDate="2017-03-11T03:43:14.983" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5193" PostTypeId="1" AcceptedAnswerId="5220" CreationDate="2015-07-16T18:13:57.097" Score="7" ViewCount="86" Body="&lt;p&gt;Is there a list of websites supplying real time seismographic information for around the world?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I could find for specific places. But I'm looking for a list so I can check for anywhere (providing, of course, they have it.)&lt;/p&gt;&#xA;" OwnerUserId="3182" LastActivityDate="2015-07-20T04:59:19.827" Title="Publicly-available real-time world-wide seismographic information?" Tags="|geophysics|seismology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5194" PostTypeId="1" AcceptedAnswerId="5196" CreationDate="2015-07-16T19:35:46.983" Score="9" ViewCount="241" Body="&lt;p&gt;Isostatic depression is normally associated with glaciation, but can other geologic processes result in similar behavior of the lithosphere? Especially, can the weight of a volcano cause the surrounding lithosphere to sink. &lt;/p&gt;&#xA;" OwnerUserId="3184" LastEditorUserId="111" LastEditDate="2015-07-16T20:50:28.060" LastActivityDate="2015-07-17T01:06:01.273" Title="Can volcanos cause isostatic depression" Tags="|volcanology|mantle|lithosphere|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5195" PostTypeId="2" ParentId="353" CreationDate="2015-07-16T19:57:14.733" Score="5" Body="&lt;p&gt;The reason we use convolution is because we consider the earth to be a linear, time-invariant, passive system. The output of any such system is the convolution of the input and the impulse response of the system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;linear&quot; means that if input x(t) produces output X(t) and input y(t) produces output Y(t), then input Ax(t)+By(t) produces output AX(t)+BY(t) [where A &amp;amp; B are constants, t is time]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;time-invariant&quot; means that if input x(t) produces output X(t), then input x(t-T) will produce output X(t-T)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;passive&quot; means that if the input starts at time T then no output is produced prior to time T.&lt;/p&gt;&#xA;" OwnerUserId="3185" LastActivityDate="2015-07-16T19:57:14.733" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5196" PostTypeId="2" ParentId="5194" CreationDate="2015-07-16T20:54:55.683" Score="7" Body="&lt;p&gt;Yes, they can. &lt;a href=&quot;https://en.wikipedia.org/wiki/Hawaiian_Trough&quot;&gt;Hawaiian Trough&lt;/a&gt; is a good example. The impact on thin oceanic crust is naturally larger/faster than on stiff continental crust. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Generally the lithosphere will always respond to load, even if it's sediments, ice or water. The process also works the other way, &lt;a href=&quot;http://www.usu.edu/geo/pederson/Pederson%20et%20al.%202002%20GSA%20Today.pdf&quot;&gt;exhumation by erosion&lt;/a&gt; ease the load and cause uplift.&lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2015-07-16T21:09:14.217" LastActivityDate="2015-07-16T21:09:14.217" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5197" PostTypeId="1" CreationDate="2015-07-16T22:49:56.373" Score="6" ViewCount="113" Body="&lt;p&gt;I'm trying to find 3-component records of the P-wave arrivals of a variety of earthquakes at seismic stations (specific earthquakes or stations aren't important, I just want a small library of these arrivals for a machine learning project). I expected there would be labeled databases of this kind of thing where I could simply browse by earthquake or station and download the data. However the request process appears much more complicated and honestly I'm very confused. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is anyone familiar with how to query these databases?&lt;/p&gt;&#xA;" OwnerUserId="3187" LastEditorUserId="32" LastEditDate="2015-07-17T02:30:01.543" LastActivityDate="2015-07-17T02:30:01.543" Title="Querying Seismic Databases" Tags="|geophysics|seismology|database|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5198" PostTypeId="2" ParentId="5194" CreationDate="2015-07-17T00:54:27.347" Score="7" Body="&lt;p&gt;Absolutely. Lithospheric flexure due to volcanic edifice emplacement is well-documented. Not only do you get isostatic depression near the volcano, but further afield you actually can have uplift due to a &quot;hinging&quot; sort of effect. Lithospheric flexure drives the growth of underwater coral atolls through subsidence at a recently emplaced volcano (coral forms at a fixed depth beneath sea level), but later can lift the same coral above sea level due to far-field volcanic emplacement, turning the underwater atoll into an island. See the seminal work on this by &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/JB083iB03p01206/abstract&quot;&gt;McNutt &amp;amp; Menard (1978)&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="63" LastEditorUserId="63" LastEditDate="2015-07-17T01:06:01.273" LastActivityDate="2015-07-17T01:06:01.273" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5199" PostTypeId="2" ParentId="5197" CreationDate="2015-07-17T02:29:48.700" Score="4" Body="&lt;p&gt;Unless they are large or famous earthquakes, I doubt you will find the waveforms for specific earthquakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What you will find is a ton of seismic data: &lt;a href=&quot;http://earthquake.usgs.gov/data/?source=sitenav&quot; rel=&quot;nofollow&quot;&gt;http://earthquake.usgs.gov/data/?source=sitenav&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;which you can request. Once you have requested (downloaded ect) the waveforms (probably in seed format) you will need to analyze the waveforms themselves to find specific earthquakes (request data from a time when you know there was an earthquake) and find the p/s/love ect wave yourself on the seismogram.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To read seed data, you can either find a matlab code or write your own! (Im sure there is a python equivalent at this point.)&lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2015-07-17T02:29:48.700" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5200" PostTypeId="1" CreationDate="2015-07-17T14:00:51.550" Score="10" ViewCount="728" Body="&lt;p&gt;I have seen pictures of the cracks in the Earth's crust in Iceland and the San Andreas fault. To my eyes, the crack is relatively wide at the surface than a few meters down seems to be very narrow or just not there. I know this might seem stupid, but how come the crack does no go all the way down to the mantle? Is it that the crack opens and then the soft rock down below slides over to fill it in again?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How deep are the cracks at fault zones, I am thinking of the Silfra crack in Iceland between Europe and the US.&lt;/p&gt;&#xA;" OwnerUserId="3196" LastEditorUserId="2536" LastEditDate="2017-06-04T12:07:44.877" LastActivityDate="2017-06-04T12:07:44.877" Title="How deep are the cracks in the earths crust at fault zones?" Tags="|geology|plate-tectonics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5201" PostTypeId="2" ParentId="5200" CreationDate="2015-07-17T15:19:32.000" Score="6" Body="&lt;p&gt;Cracks (actually the right word is fault or in some situations rift) can only occur in brittle material and only the Earths upper crust (top 5-25 km) is brittle. The lower crust and mantle are ductile, i.e., they have a relatively lower viscosity which means that they can indeed crack on short time scales but will heal quickly due to high temperatures and pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: In some ways you can think the lower crust and mantle to be like pitch (tar), which is solid at room temperature but flows over longer periods. E.g., see &lt;a href=&quot;https://en.wikipedia.org/wiki/Pitch_drop_experiment&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt; link which also happens to be the worlds longest running experiment.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2015-07-17T15:27:41.553" LastActivityDate="2015-07-17T15:27:41.553" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5202" PostTypeId="2" ParentId="4272" CreationDate="2015-07-18T01:27:52.440" Score="3" Body="&lt;p&gt;A difficulty in finding a resource that provides an estimate of the length of the entire American Cordillera is as, @fre0n states in the comments&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;there is very few standard mention regarding this unit as a whole, instead it is more often localized&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As can be read in the Wikipedia article &lt;a href=&quot;https://en.wikipedia.org/wiki/American_Cordillera&quot; rel=&quot;nofollow&quot;&gt;American Cordillera&lt;/a&gt;, where they state that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The American Cordillera is a chain of mountain ranges (cordillera) that consists of an almost continuous sequence of mountain ranges that form the western &quot;backbone&quot; of North America, Central America, South America and Antarctica. It is also the backbone of the volcanic arc that forms the eastern half of the Pacific Ring of Fire.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The Wikipedia article lists the constituent mountain ranges as being a line of overlapping mountain ranges from the Alaska and Brooks Range right through the Andes to the southern tip of South America, also suggesting that the Cordillera could&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;possibly be followed through the arcuate South Georgia Ridge across the Southern Ocean to the mountains of Graham Land on the Antarctic Peninsula.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Given the earlier definition of the Cordillera being&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;an almost continuous sequence of mountain ranges that form the western &quot;backbone&quot; of North America, Central America, South America and Antarctica.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;according to Google Maps, where I used this definition and traced the distance (right-click on map -&gt; &lt;code&gt;Measure distance&lt;/code&gt; -&gt; select points along the 'spine' of the Americas and Antarctica), I determined an estimate of the total length as being approximately &lt;strong&gt;17,000 km&lt;/strong&gt; (or about 21,500 km if the South Georgia Ridge and Graham Land Mountains are included).&lt;/p&gt;&#xA;" OwnerDisplayName="user2872" LastActivityDate="2015-07-18T01:27:52.440" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5203" PostTypeId="2" ParentId="4804" CreationDate="2015-07-18T04:20:02.153" Score="13" Body="&lt;p&gt;Neither. The Sahara Desert is heterogenous. It’s yellow, red, orange, brown, black, and even green in certain places and at certain times of year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Slightly less cheeky answer: neither. Both examples are both approximations of human vision, displayed on computer screens that can be highly variable. The 2002 version of the Blue Marble is a composite of 4 months of atmospherically-corrected data in narrow wavelength bands. The composite data is scaled to approximate the nonlinear response of human vision. In particularly bright areas the image is clipped in some bands, leading to incorrect hue and loss of contrast.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For all the gory details, here’s the user’s guide for the MODIS land surface reflectance product (which has always looked slightly greenish to me): &lt;a href=&quot;http://modis-sr.ltdri.org/guide/MOD09_UserGuide_v1.4.pdf&quot;&gt;http://modis-sr.ltdri.org/guide/MOD09_UserGuide_v1.4.pdf&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Apollo 17 Blue Marble is a color-corrected scan of 40-year-old film (stored in a freezer at NASA’s Johnson Space Center) and is also not a particularly good representation of what an astronaut would see (as Pont commented earlier). The best description of the appearance of the Earth from space is from astronaut Piers Sellers, who said it’s “brilliant blue, and too bright to look at directly—like sunlight reflected off snow while skiing at high altitude”.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Brutally honest answer: neither. To paraphrase Mapbox’s Charlie Loyd, there’s an irreducible subjectivity to color. How we perceive color is affected by ambient light, adjacent colors, overall amount of light, individual physiology, our age, and probably mood and what we had to eat for breakfast. Viewed from space there are even more variables: particularly atmospheric conditions (which influence both incident and reflected light) and viewing angle. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Current state-of-the-art is probably NOAA View, &lt;a href=&quot;http://www.nnvl.noaa.gov/view/#TRUE&quot;&gt;http://www.nnvl.noaa.gov/view/#TRUE&lt;/a&gt; which uses a multi-band algorithm to simulate true color with Visible Infrared Imaging Radiometer Suite (VIIRS) data. According to that algorithm, the Sahara is more red than yellow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the record, I’ve worked on color-correcting MODIS imagery, the Blue Marble datasets, and astronaut photography on the NASA Earth Observatory &amp;amp; Visible Earth sites (including the referenced version of AS17-148-22727—unfortunately I can’t find the original TIFF.) Perhaps that means I think the Sahara is both ochre and yellow. I also wrote the guide to color-correcting Landsat imagery linked by Jezibelle (thank you).&lt;/p&gt;&#xA;" OwnerUserId="3201" LastActivityDate="2015-07-18T04:20:02.153" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5204" PostTypeId="1" CreationDate="2015-07-18T05:22:06.430" Score="8" ViewCount="842" Body="&lt;p&gt;There is news on the web saying that there will be &lt;a href=&quot;http://astronomynow.com/2015/07/17/diminishing-solar-activity-may-bring-new-ice-age-by-2030/&quot;&gt;Mini Ice Age in couple of decades&lt;/a&gt;.&lt;br&gt;&#xA;The question is: Will this Mini Ice Age take away all the excessive heat and prevent Global Warming?&lt;/p&gt;&#xA;" OwnerUserId="3203" LastEditorUserId="3203" LastEditDate="2015-07-18T05:48:28.940" LastActivityDate="2018-04-17T05:02:45.780" Title="Will the Mini Ice Age solve our Global Warming Heat problem" Tags="|climate-change|ice-age|" AnswerCount="6" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="5205" PostTypeId="2" ParentId="5204" CreationDate="2015-07-18T16:06:50.033" Score="7" Body="&lt;p&gt;The &quot;mini ice age&quot; hypothesis is hype (note the lack of references to &lt;em&gt;supporting&lt;/em&gt; peer-reviewed literature). For scientific information on its possibility, see &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/grl.50361/abstract&quot; rel=&quot;nofollow&quot; title=&quot;this GRL article&quot;&gt;this GRL article&lt;/a&gt; by Meehl &lt;em&gt;et al.&lt;/em&gt; (2013). From the abstract:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A future Maunder Minimum type grand solar minimum, with total solar irradiance reduced by 0.25% over a 50 year period from 2020 to 2070, is imposed in a future climate change scenario experiment (RCP4.5)... After the initial decrease of solar radiation in 2020, globally averaged surface air temperature cools relative to the reference simulation by up to several tenths of a degree Centigrade. By the end of the grand solar minimum in 2070, the warming nearly catches up to the reference simulation. Thus, a future grand solar minimum could slow down but not stop global warming.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The article is open access and can be read without payment or subscription.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Meehl, G. A., J. M. Arblaster, and D. R. Marsh (2013), Could a future “Grand Solar Minimum” like the Maunder Minimum stop global warming?, Geophys. Res. Lett., 40, 1789–1793, doi:10.1002/grl.50361.&lt;/p&gt;&#xA;" OwnerUserId="30" LastEditorUserId="94" LastEditDate="2015-07-20T09:25:00.223" LastActivityDate="2015-07-20T09:25:00.223" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5206" PostTypeId="2" ParentId="5173" CreationDate="2015-07-19T01:29:46.663" Score="3" Body="&lt;p&gt;I haven't found proper references yet, but this hasn't gotten an answer yet. To speculation!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Long-lived (non-precipitating) clouds can decrease solar insolation at the surface, reducing convection and mixing below the cloud and increasing pollutant concentrations. If clouds are just a symptom of a high-humidity environment, that can promote the condensation of semi-volatile species into particulates (nitrate, ammonia, some organics) if you don't count phase change as a reaction. Convective storms are associated with a lot of mixing, both within the boundary layer and between the boundary layer and the free troposphere, reducing concentrations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Without the photolysis or rainout processes, I don't know enough about different cloud types and environments to speculate further. I'm hoping this at least sparks more discussion.&lt;/p&gt;&#xA;" OwnerUserId="1342" LastActivityDate="2015-07-19T01:29:46.663" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5207" PostTypeId="2" ParentId="923" CreationDate="2015-07-19T01:47:56.603" Score="5" Body="&lt;p&gt;More than a year later, I'm doing a preliminary literature survey (noting that infrasound propagation is used in nuke test ban treaty verification):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://dx.doi.org/10.1016/0012-8252(77)90063-0&quot; rel=&quot;nofollow&quot;&gt;https://dx.doi.org/10.1016/0012-8252(77)90063-0&lt;/a&gt; W.L. Jones. Waves in the atmosphere; Atmospheric infrasound and gravity waves, their generation and propagation. (1977)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://dx.doi.org/10.1111/j.1365-246x.2011.04975.x&quot; rel=&quot;nofollow&quot;&gt;https://dx.doi.org/10.1111/j.1365-246x.2011.04975.x&lt;/a&gt; Green et al. Infrasound radiated by the Gerdec and Chelopechene explosions: propagation along unexpected paths. (2011)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://dx.doi.org/10.1111/j.1365-246x.2010.04925.x&quot; rel=&quot;nofollow&quot;&gt;https://dx.doi.org/10.1111/j.1365-246x.2010.04925.x&lt;/a&gt; Groot-Hedlin, Hedlin, Walker. Finite difference synthesis of infrasound propagation through a windy, viscous atmosphere: application to a bolide explosion detected by seismic networks. (2011)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://dx.doi.org/10.1029/2011jd017014&quot; rel=&quot;nofollow&quot;&gt;https://dx.doi.org/10.1029/2011jd017014&lt;/a&gt; Evers et al. Anomalous infrasound propagation in a hot stratosphere and the existence of extremely small shadow zones. (2012)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://dx.doi.org/10.1121/1.1903454&quot; rel=&quot;nofollow&quot;&gt;https://dx.doi.org/10.1121/1.1903454&lt;/a&gt; Liszka. Long-distance propagation of infrasound from artificial sources. (1974)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://dx.doi.org/10.3390/ani3020349&quot; rel=&quot;nofollow&quot;&gt;https://dx.doi.org/10.3390/ani3020349&lt;/a&gt; Kelley, Garstang. On the possible detection of lightning storms by elephants. (2013) (courtesy of &lt;a href=&quot;https://earthscience.stackexchange.com/users/64/casey&quot;&gt;casey&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;... and a ton of others. When I have enough time, will study. Others may surely use the leads I collected to post an answer before that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Things to keep in mind: anomalous propagation, whether acoustic or electromagnetic, below the surface or above it, is based on speed inversions. Whenever there are countervailing trends in salinity (for water)/water content (for air), density, and temperature, natural waveguides may exist.&lt;/p&gt;&#xA;" OwnerUserId="269" LastEditorUserId="269" LastEditDate="2015-07-22T19:39:07.437" LastActivityDate="2015-07-22T19:39:07.437" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5208" PostTypeId="2" ParentId="5204" CreationDate="2015-07-19T04:08:21.123" Score="18" Body="&lt;p&gt;I'm going to try to answer this, though it's actually a very hard question depending on how close you look at it.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lets start with the American Physical Society's statement on climate change - which, they've made an effort to balance out following their 2007 statement of &quot;evidence is incontrovertible&quot; that got some members upset and lead to a handful of high profile resignations.    More on that &lt;a href=&quot;http://www.scientificamerican.com/article/physicists-battle-over-the-meaning-of-incontrovertible-in-global-warming-fight/&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is their more balanced statement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.aps.org/policy/reports/popa-reports/energy/climate.cfm&quot; rel=&quot;noreferrer&quot;&gt;http://www.aps.org/policy/reports/popa-reports/energy/climate.cfm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The relationships between the atmospheric concentration of greenhouse&#xA;  gases and their radiative effects are well quantified. Forcing from&#xA;  the long-lived greenhouse gases: &lt;strong&gt;carbon dioxide, methane, and nitrous&#xA;  oxide, is presently about 2.5 Watts per meter squared (W/m2). Of this&#xA;  total, 1.6 W/m2 is from carbon dioxide alone&lt;/strong&gt;. The total anthropogenic&#xA;  forcing is uncertain, particularly because the magnitude of the&#xA;  negative forcing associated with sulfate aerosols is unclear. While&#xA;  changes in solar irradiance may have affected global climate in the&#xA;  last century, a 0.15% change irradiance, the order of estimated&#xA;  changes, results in only a 0.36 W/m2 forcing.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and, numbers vary, but this seemed a pretty fair article on Solar Irradiance:   &lt;a href=&quot;http://earthobservatory.nasa.gov/Features/SORCE/sorce_03.php&quot; rel=&quot;noreferrer&quot;&gt;http://earthobservatory.nasa.gov/Features/SORCE/sorce_03.php&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It says:   &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The number of sunspots visible from the Earth not only changes from&#xA;  day to day, but also in cycles that can last from decades to centuries&#xA;  to millennia. The most well-known and well-analyzed of these cycles is&#xA;  the 11-year sunspot cycle. Over the course of 11 years, the yearly&#xA;  average number of sunspots and faculae slowly increases and then&#xA;  return to normal levels before rising again for the subsequent cycle.&#xA;  The change in the Sun’s yearly average total irradiance during an&#xA;  11-year cycle is on the order of 0.1 percent or &lt;strong&gt;1.4 watts per square&#xA;  meter.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, 1.6 watts per square meter from Co2 (2.5 watts total) and (up to) 1.4 watts per square meter low to peak solar irradiance, but there's a problem with that 1.4 number.    It's low to high, meaning low to average is 0.7 watts per square meter and that's how we should measure assuming the sun enters a grand minimum, we should measure against the average, so the real number is 0.7 watts per square meter drop - assuming the study is right and the sun does enter a new Maunder Minimum.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Skeptical Science posts a similar number:   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/QE6X5.jpg&quot; alt=&quot;http://www.skepticalscience.com/graphics/Solar_vs_temp_500.jpg&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source:  &lt;a href=&quot;https://www.skepticalscience.com/solar-activity-sunspots-global-warming.htm&quot; rel=&quot;noreferrer&quot;&gt;https://www.skepticalscience.com/solar-activity-sunspots-global-warming.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The variation in their chart appears to be similar to the 0.7 variation we should expect from the NASA article, average to low range.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's also the, all but guarantee that CO2 will continue to rise, at least, for several more years, so the APS estimate is likely to go up.   Also, the APS number doesn't include feedback mechanisms - and they say as much in the article linked above:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The largest source of uncertainty lies in determining the magnitude of&#xA;  climate feedbacks. For example, an increase in trapped radiation and&#xA;  the associated warming is expected to increase the level of water&#xA;  vapor in the atmosphere, which would tend to further enhance the&#xA;  greenhouse effect ó a positive feedback. An example of a negative&#xA;  feedback would be an increase in clouds that reflected more sunlight&#xA;  back into space. The actual feedback from changes in clouds is&#xA;  uncertain since they also act to trap outgoing infrared radiation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Now, the positive feedback from water vapor is a given and the negative feedback from clouds is more uncertain, so I think the APS article is a little bit more friendly to the skeptics than the actual science (IMHO).  Clouds reflect sunlight, but clouds also trap heat at night.  The total cloud effect is, well, a little more cloudy than APS' one line suggests.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Skeptical Science has an article on cloud feedback here:  &lt;a href=&quot;http://www.skepticalscience.com/clouds-negative-feedback.htm&quot; rel=&quot;noreferrer&quot;&gt;http://www.skepticalscience.com/clouds-negative-feedback.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, where does that leave us:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Well, first, the study that the sun is going to enter a grand minimum in the next few decades needs to be verified, lets start there.   A whole bunch of bad science has been published by those trying to disprove, discredit or cast doubt on climate change - so skeptisism of new studies first, especially on this topic, but, lets say they're right - which was the original question.   Would that be sufficient to stop man made global warming?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No.   I think it's pretty likely it would be insufficient.   0.7 is less than 2.5.   But, if they're right, it's still kind of good news, cause it would soften the blow - and that's a good thing.   I hope they are right.   But the sun's maximums and minimums have a pretty small effect on climate change.  Maybe a degree here or there.   Man made climate change should be 2 degrees by the end of the century, and perhaps more if left unaddressed in centuries that follow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As Steve Emmerson points out, the effect of the Maunder Minimum isn't 100% accepted as the sole cause of the Mini ice age.   There's still some unknowns, but I feel, with pretty high confidence, that the sun entering a new grand minimum would be insufficient to stop the warming, but it might slow it down, a little.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Too long?   I can try to clean it up a bit later.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2015-07-20T18:30:10.137" LastActivityDate="2015-07-20T18:30:10.137" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5210" PostTypeId="2" ParentId="5204" CreationDate="2015-07-19T06:49:11.773" Score="11" Body="&lt;p&gt;No, solar activity will not help offset anthropogenic warming in any significant way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recent research says a grand solar minimum would cause no more than 0.3C cooling over the 21st century [Feulner &amp;amp; Rahmstorf (2010), Jones et al. (2012), Anet et al. (2013)]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But to see the influence of the solar cycle on the earth's climate together with the effect of anthropogenic forcing see @userLTK's chart - it is key. Roughly after 1960 solar activity declines on average while temperature rampantly rises. Why? &lt;a href=&quot;http://www.sciencemag.org/content/330/6002/356.abstract&quot;&gt;Atmospheric CO2: [the] Principal Control Knob Governing Earth’s Temperature &lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although solar activity is modulating the earth's temperature the effect is relatively small and for all practical purposes - negligible. Otherwise the past 12,000 years of civilization would have been much tougher to endure.&lt;/p&gt;&#xA;" OwnerUserId="200" LastActivityDate="2015-07-19T06:49:11.773" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5211" PostTypeId="1" AcceptedAnswerId="5212" CreationDate="2015-07-19T09:44:19.087" Score="12" ViewCount="784" Body="&lt;p&gt;When thinking about the formation of the current continents from a super-continent, it's clear that this is a gradual process, but there must be certain areas on earth which were once joined and were the &quot;last&quot; to break apart from Pangea. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do we know when and where these rifting / break-up events took place?&lt;/p&gt;&#xA;" OwnerUserId="614" LastEditorUserId="2639" LastEditDate="2015-07-22T04:20:41.150" LastActivityDate="2015-07-26T19:49:31.207" Title="When did the last rifting / break-up event occur?" Tags="|continental-rifting|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5212" PostTypeId="2" ParentId="5211" CreationDate="2015-07-19T11:02:05.130" Score="16" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Rift&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rifting&lt;/a&gt; is an ongoing process. At the moment, e.g. East Africa is &lt;a href=&quot;https://en.wikipedia.org/wiki/East_African_Rift&quot; rel=&quot;nofollow noreferrer&quot;&gt;rifting&lt;/a&gt; apart from the Nubian plate, we also see rifting of continental plates elsewhere, eg &lt;a href=&quot;https://en.wikipedia.org/wiki/Rio_Grande_rift&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rio Grande&lt;/a&gt;. New continents are being formed, but it doesn't happen on a human time scale. Modellers of &lt;a href=&quot;http://www.livescience.com/18387-future-earth-supercontinent-amasia.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;future geography&lt;/a&gt; have a &lt;a href=&quot;http://www.sciencearchive.org.au/nova/newscientist/104ns_011.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;difficult task&lt;/a&gt; to decide what rifts that will stop and what rift that eventually will result in a new continent. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;See yellow marked faults and rifts:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/Y22u1.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Madagascar_Plate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Madagascar&lt;/a&gt; is sometimes refereed to as the &lt;em&gt;eight continent&lt;/em&gt;, not only of biogeographic reasons. It was rifting away from Africa and later India during mesozoic time, &lt;a href=&quot;http://www.researchgate.net/publication/248564376_The_Great_Rift_Valley_of_Madagascar_An_extension_of_the_AfricaSomali_diffusive_plate_boundary&quot; rel=&quot;nofollow noreferrer&quot;&gt;starting 160 Ma&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The last rifting that resulted in the present continents I can think about (probably the community can come up with a later event!), would be the North Atlantic breakup, that is still ongoing, but the last part of separation of present continents was the &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0040195108000024#&quot; rel=&quot;nofollow noreferrer&quot;&gt;opening&lt;/a&gt; of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Fram_Strait&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fram Strait&lt;/a&gt; &lt;a href=&quot;http://epic.awi.de/16218/&quot; rel=&quot;nofollow noreferrer&quot;&gt;16-10 Ma&lt;/a&gt;. This separated Greenland from the European plate and had a &lt;a href=&quot;http://www.sciencedaily.com/releases/2011/01/110127141659.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;large impact&lt;/a&gt; on the Arctic Ocean conditions. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2015-07-19T11:10:41.617" LastActivityDate="2015-07-19T11:10:41.617" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5217" PostTypeId="2" ParentId="5021" CreationDate="2015-07-19T19:15:58.240" Score="8" Body="&lt;p&gt;The short answer is that most of the Earth's original allotment of CO&lt;sub&gt;2&lt;/sub&gt; got locked up in various carbonate minerals, largely calcite (limestone, marble, and chalk).  According to &lt;a href=&quot;http://alliance.la.asu.edu/temporary/students/Phil/MineralCarbonation.pdf&quot;&gt;this&lt;/a&gt; article there is currently ~800 gigatons of carbon in the atmosphere today; there is ~39,000,000 gigatons of carbon locked up in calcite minerals. All that carbon was once in the atmosphere as CO&lt;sub&gt;2&lt;/sub&gt;. Rainfall dissolved CO&lt;sub&gt;2&lt;/sub&gt; into H&lt;sub&gt;2&lt;/sub&gt;CO&lt;sub&gt;3&lt;/sub&gt; (carbonic acid) which then reacted with calcium-containing minerals and then precipitated out in the world's oceans where they formed early calcite deposits.&lt;br&gt;&lt;br&gt;If not for this process the Earth's climate would not be too unlike Venus'.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2015-07-19T19:15:58.240" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5218" PostTypeId="1" CreationDate="2015-07-20T02:23:24.090" Score="8" ViewCount="1271" Body="&lt;p&gt;What is the best way to accurately measure wavelength between crests from a pier?&lt;/p&gt;&#xA;" OwnerUserId="3207" LastEditorUserId="2470" LastEditDate="2015-07-20T03:15:03.690" LastActivityDate="2015-07-20T16:05:03.897" Title="What is the best way to accurately measure wavelength between crests on a pier?" Tags="|waves|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5219" PostTypeId="1" CreationDate="2015-07-20T04:55:52.083" Score="6" ViewCount="210" Body="&lt;p&gt;On July 19, 2015 there was record rainfall over the Los Angeles and San Diego areas.  This is amidst a historic drought and the rain is needed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This article:&#xA;&lt;a href=&quot;http://www.weather.com/storms/hurricane/news/southwest-flood-threat-july-2015-tropical-storm-hurricane-dolores&quot;&gt;http://www.weather.com/storms/hurricane/news/southwest-flood-threat-july-2015-tropical-storm-hurricane-dolores&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;states that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Widespread showers and thunderstorms across the Desert Southwest are being fueled by moisture from former Hurricane Dolores.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Los Angeles and San Diego set all-time rainfall records for the month of July on Saturday.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;National Weather Service meteorologist called [it] &quot;super historic.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What is the significance of the &quot;super historic&quot; rainfall for July in California (July 19, 2015) in terms of climate change and water reservoirs used for municipalities?  In other words, what is the likelihood that climate change could bring more of these types of rain events in the future?  Related, what is the relative impact on water reservoirs and how much relief from the drought does such an event provide?  Does California have a long-term plan to capture more of this type of flash-flood rainfall in the future?&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2015-07-21T02:03:16.617" Title="What is the significance of the &quot;super historic&quot; rainfall for July 2015 in southern California?" Tags="|climate|climate-change|rain|california|drought|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="5220" PostTypeId="2" ParentId="5193" CreationDate="2015-07-20T04:59:19.827" Score="3" Body="&lt;p&gt;The &lt;a href=&quot;http://ds.iris.edu/seismon/&quot; rel=&quot;nofollow&quot;&gt;IRIS Seismic Monitor&lt;/a&gt; is one.&lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2015-07-20T04:59:19.827" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="5221" PostTypeId="2" ParentId="5218" CreationDate="2015-07-20T05:01:29.990" Score="5" Body="&lt;p&gt;One simple way is to measure the period $T$ by timing the arrival of each  crest and estimate the wave speed $c$ from the depth of the water column $d$. Then one can compute a wavelength $\lambda$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming the waves are shallow-water waves ($d/\lambda &amp;lt; 1/11$) and linear (modeled by a sine or cosine function), the error should be no more than 10% (is that accurate enough? It gets more complicated otherwise).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since we assumed these are shallow water waves they are nondispersive and the speed is simply $c = \sqrt{gd}$, where $g$ is the gravitational acceleration.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, the wavelength is&#xA;$$\lambda = c\ T=\sqrt{gd}\ T\,.$$ &lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="192" LastEditDate="2015-07-20T16:05:03.897" LastActivityDate="2015-07-20T16:05:03.897" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5222" PostTypeId="1" CreationDate="2015-07-20T07:35:46.407" Score="5" ViewCount="2321" Body="&lt;p&gt;My son recently got a &lt;a href=&quot;http://geology.com/rock-tumbler/&quot; rel=&quot;nofollow&quot;&gt;rock tumbler&lt;/a&gt; and I was wondering if anybody knows of any resources that would show pictures of the different types of rocks as they would be found on the ground. I live in Chino Hills CA and we have many trails. I wanted to be able to tell the difference between something worth tumbling and something that isn't. &lt;/p&gt;&#xA;" OwnerUserId="3210" LastEditorUserId="595" LastEditDate="2015-07-20T08:38:36.370" LastActivityDate="2015-08-21T13:06:29.163" Title="How to find rocks worth tumbling?" Tags="|rocks|california|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5223" PostTypeId="1" AcceptedAnswerId="5225" CreationDate="2015-07-20T12:35:21.317" Score="10" ViewCount="455" Body="&lt;p&gt;What is the cloud formation &lt;a href=&quot;https://video-fra3-1.xx.fbcdn.net/hvideo-xpf1/v/t42.1790-2/11015023_903265136402907_1288638676_n.mp4?efg=eyJybHIiOjMwMCwicmxhIjo1MTJ9&amp;amp;rl=300&amp;amp;vabr=144&amp;amp;oh=4ae988ce8a46829aa85215887105a8ff&amp;amp;oe=55AD0D67&quot; rel=&quot;noreferrer&quot;&gt;in this video&lt;/a&gt;? I don't know where this footage was taken.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/3p7B9.png&quot; alt=&quot;Snapshot from linked video. Unknown source&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://video-fra3-1.xx.fbcdn.net/hvideo-xpf1/v/t42.1790-2/11015023_903265136402907_1288638676_n.mp4?efg=eyJybHIiOjMwMCwicmxhIjo1MTJ9&amp;amp;rl=300&amp;amp;vabr=144&amp;amp;oh=4ae988ce8a46829aa85215887105a8ff&amp;amp;oe=55AD0D67&quot; rel=&quot;noreferrer&quot;&gt;Here's the link to the video again.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3211" LastEditorUserId="28050" LastEditDate="2015-07-20T13:37:50.167" LastActivityDate="2015-07-20T14:43:26.733" Title="What is this cloud formation?" Tags="|meteorology|clouds|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5224" PostTypeId="2" ParentId="5218" CreationDate="2015-07-20T13:33:58.750" Score="1" Body="&lt;p&gt;Ideally you'd like to avoid having to estimate anything. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Depending on the shape and orientation of the pier relative to the waves, you might be able to find some volunteers (at least 1 anyway) and space them out at approximately the right distance. Then get them to raise a hand when a crest passes them. Adjust their spacing until they are raising their hand at the same time. If the crests are simultaneous and there is only one trough between them, they are one wavelength apart.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might need to adjust for the angle of the pier, for example in this case, wavelength $\lambda$ is related to the inter-volunteer distance $d$ and pier angle $\theta$ as $\lambda = d \cos\theta$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/irgLR.png&quot; alt=&quot;measuring wavelength from a pier&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Measure as many crests as you can, keeping track of the tide. As Isopycnal Oscillation explained in another answer, the wavelength with vary with water depth. Perhaps measure around high tide, and again around low tide. Take the means of your various sets of measurements.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You'll need a longish tape measure, or phones with GPS, and a stopwatch, or phone with clock, if you want to measure periods as well (you might as well).&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2015-07-20T15:28:59.237" LastActivityDate="2015-07-20T15:28:59.237" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5225" PostTypeId="2" ParentId="5223" CreationDate="2015-07-20T14:43:26.733" Score="9" Body="&lt;p&gt;This a type of &lt;em&gt;arcus cloud&lt;/em&gt; called a &lt;em&gt;shelf cloud&lt;/em&gt; and is caused by moist air rising over cool thunderstorm outflow.  These clouds can look quite dramatic but do not pose any threats themselves.  However, they can signal the presence of strong winds behind the gust front.&lt;/p&gt;&#xA;&lt;p&gt;These clouds can often be associated with strong convection -- squall lines, supercells, etc.  These storms often have strong inflow coming from ahead of the storm supplying the storm with moisture.  The storm is producing rain-cooled air and this dense air wants to spread out along the ground.  If the outflow becomes too cool (relative) or the inflow weakens, the storm outflow can race ahead of the storm.  This will produce strong winds as the gust front surges ahead and if the inflow is moist enough it will produce a cloud as it rises up and over the cool outflow.  This cloud marking the gust front as it the rises up and over is a shelf cloud.&lt;/p&gt;&#xA;&lt;p&gt;These definitions are taken from a &lt;a href=&quot;http://www.srh.noaa.gov/oun/?n=spotterglossary#Introduction&quot; rel=&quot;noreferrer&quot;&gt;NWS storm spotter glossary&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Arcus&lt;/strong&gt; - A low, horizontal cloud formation associated with the leading edge of thunderstorm outflow (i.e., the gust front). Roll clouds and shelf clouds both are types of arcus clouds.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Shelf Cloud&lt;/strong&gt; - A low, horizontal wedge-shaped arcus cloud, associated with a thunderstorm gust front (or occasionally with a cold front, even in the absence of thunderstorms). Unlike the roll cloud, the shelf cloud is attached to the base of the parent cloud above it (usually a thunderstorm). Rising cloud motion often can be seen in the leading (outer) part of the shelf cloud, while the underside often appears turbulent, boiling, and wind-torn.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="64" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-07-20T14:43:26.733" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5227" PostTypeId="2" ParentId="5219" CreationDate="2015-07-21T02:03:16.617" Score="6" Body="&lt;p&gt;This event is &quot;super historic&quot; only because of its proximity to the coast.  It is fairly common to get flash flooding in the mountains and deserts of Socal at least a few times each summer, due to the Southwest Monsoon.  This event was different in that a dying tropical system moving north off of the coast of Mexico interacted with a trough off of the Northern California coast.  The combination of these two essentially funneled tropical moisture north directly into the coastal regions of Southern California.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Linking single events to long term global change is virtually impossible to do reliably, so I won't speculate. However one could argue that rising sea surface temperatures could allow tropical systems to stay more organized near Southern California, and increase the probability of events like this. But again, it is never a good idea to try and link a localized extreme event with a global phenomenon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of drought relief and reservoir storage these rains have virtually zero impact.  They impacted the southern third of California, while the majority of water storage is in the central and northern part of the state along the Sierras. The rain came down pretty quick and didn't soak in to any of the soils, so vegetation will still be just as dry as before the rain. California needs heavy snows in the Sierras for any serious drought relief. Although these rains have given many people a false sense of security.&lt;/p&gt;&#xA;" OwnerUserId="3214" LastActivityDate="2015-07-21T02:03:16.617" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5228" PostTypeId="1" AcceptedAnswerId="5252" CreationDate="2015-07-21T05:07:28.010" Score="3" ViewCount="616" Body="&lt;p&gt;I am studying crystals and I learned that there are 32 &lt;a href=&quot;https://en.wikipedia.org/wiki/Crystal_system&quot; rel=&quot;nofollow&quot;&gt;crystal classes&lt;/a&gt; with well-described data regarding symmetries. I have visited a few sites and am having difficulty determining the significance of these classifications. For example, how can any crystal be categorized under these 32 classes? I understand that the information exists somewhere within the symmetry data, but it's difficult to tell what it says; I'm trying to learn a lot of foreign concepts at once (space groups, lattices, symmetry concepts, etc.).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suppose I'm asking two questions: how can I determine the class a mineral falls under and how were the 32 classes determined?&lt;/p&gt;&#xA;" OwnerUserId="3209" LastEditorUserId="3209" LastEditDate="2015-07-23T01:43:51.097" LastActivityDate="2015-07-25T04:17:16.623" Title="Significance of crystal classes in crystallography" Tags="|geology|mineralogy|crystallography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5229" PostTypeId="1" AcceptedAnswerId="5230" CreationDate="2015-07-21T14:01:38.167" Score="7" ViewCount="237" Body="&lt;p&gt;There is as huge uplift in the image quality near and under salt bodies (e.g. the Middle Miocene of the deepwater Gulf of Mexico) by using reverse time migration or RTM. We can now make accurate structural interpretation in places we couldn't just see using Kirchhoff migration.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it proper to make an amplitude analysis of RTM migrated data to invert for reservoir properties? Do RTM horizon amplitudes relate to rock properties?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I figure this will depend on the specific vendor implementation of RTM, and the assumptions made to speed up the code, but in its pure form is RTM amplitude friendly?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please help. Any literature on the subject is much appreciated.&lt;/p&gt;&#xA;" OwnerUserId="3215" LastEditorUserId="2680" LastEditDate="2015-11-14T16:22:12.490" LastActivityDate="2015-11-14T16:22:12.490" Title="Should RTM amplitudes (pre- and post-stack) be related to rock physics properties?" Tags="|geophysics|seismology|inversion|seismic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5230" PostTypeId="2" ParentId="5229" CreationDate="2015-07-21T16:29:42.283" Score="8" Body="&lt;p&gt;&lt;strong&gt;It depends on the implementation, but bare-bones reverse time migration is usually not amplitude friendly.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem is that the ideal imaging condition — deconvolution — is difficult to apply or unstable in the time domain. So cross-correlation is used instead, and this loses the relative amplitude information... so amplitudes are no longer necessarily related to reflection coefficients. Since this is the assumption of inversion (e.g. AVO inversion), an RTM volume could give spurious results.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Several vendors have devised ways to compensate for this. For example, Zhang &amp;amp; Sun (2009; &lt;a href=&quot;http://www.cgg.com/technicalDocuments/cggv_0000005143.pdf&quot;&gt;&lt;em&gt;First Break&lt;/em&gt;, vol 26&lt;/a&gt;) described one of CGG's methods. Zhang et al. have written more recently (2013; &lt;a href=&quot;http://www.cgg.com/technicalDocuments/cggv_0000014832.pdf&quot;&gt;EAGE London&lt;/a&gt;) about how this processing has evolved. Cogan et al (2011; &lt;a href=&quot;http://www.slb.com/~/media/Files/technical_papers/seg/seg2011926.pdf&quot;&gt;SEG Annual Meeting&lt;/a&gt;) have written about Schlumberger's normalization algorithms, which aim to achieve the same goal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Those papers also contain nice explanations of why RTM is not ordinarily amplitude friendly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My advice is to talk at length to your vendor about the processing applied, and the attention paid to phase and amplitude. Ask lots of questions. Most processors (generalizing horribly) are either over-enthusiatic about treatments, especially new and/or proprietary ones, or ignorant of your needs as an interpreter–analyst. So if you're actually in the middle of processing now, test everything, ideally against geological data (like a synthetic).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lots of processing steps can hurt amplitudes, and inversion can work in surprisingly poor data... so assume nothing, and never give up!&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-07-21T16:29:42.283" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5231" PostTypeId="2" ParentId="5173" CreationDate="2015-07-21T18:43:01.697" Score="2" Body="&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Typically low pressure systems bring the most amount of clouds. In high pressure systems, clouds are typically high cirrus or convectively driven cumulus (or cumuliform clouds, such as cumulonimbus), though there are exceptions.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Convection, which is mostly what people think about when considering thermodynamics can lift surface pollution into the mixed layer and may return the next day. Boundary layer height is very important for air pollution, as it is represented in a concentration, i.e. mass per unit volume. Inversions, especially increase pollution.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Humidity can cause small particles, mostly hygroscopic particles to swell to measurable levels. This changes the mass.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Cloud height: This affects the boundary layer. If it increases the height of the boundary layer, all things being equal, will decrease the levels of pollution. If it decreases the boundary layer, all things being equal, it will decrease pollution.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Cloud shape is only as important on how the cloud is formed, sustained, and other relative details.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;You may also want to pay attention to air pollution advection, or mixing. Knowing the quality of the air from where the clouds and wind is blowing is important. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;tl;dr If it decreases the boundary layer height, expect air pollution to increase.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2015-07-21T18:43:01.697" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5232" PostTypeId="1" AcceptedAnswerId="5234" CreationDate="2015-07-21T19:39:25.807" Score="8" ViewCount="236" Body="&lt;p&gt;(How) Is it possible to tell the difference between a man made explosive crater and an impact crater?&lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorDisplayName="user20559" LastEditDate="2021-06-25T11:03:10.477" LastActivityDate="2021-06-25T11:03:10.477" Title="How to distinguish an explosion crater from an impact crater?" Tags="|geology|impact-craters|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5233" PostTypeId="1" CreationDate="2015-07-21T22:00:28.990" Score="7" ViewCount="5562" Body="&lt;p&gt;I am finding surprisingly little information about this. I imagine that the process is somewhat like foliation except because the particles that go into marble (to my knowledge) don't have any noticeable elongation you get more amorphous billowing shapes rather than more regular layers. Any more details on this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7ulJm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7ulJm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: Or does it have something to do with the magma intrusions that contribute to the marble formation process?&lt;/p&gt;&#xA;" OwnerUserId="3217" LastEditorUserId="595" LastEditDate="2016-01-12T19:09:16.067" LastActivityDate="2016-01-13T04:28:20.683" Title="How do the swirls and veins in marble form in detail?" Tags="|geology|metamorphism|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5234" PostTypeId="2" ParentId="5232" CreationDate="2015-07-21T23:28:00.643" Score="8" Body="&lt;p&gt;A manmade crater would leave behind traces of the chemical(s) used to create it (C4, TNT, ANFO, etc.). Assuming the impactor were large enough, there would be traces of shocked quartz or other shocked stone in and around the crater. If the impactor landed in limestone, then there would be significant quantities of quicklime. (I'm purposely omitting thermonuclear devices here.)&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2015-07-21T23:28:00.643" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5235" PostTypeId="1" AcceptedAnswerId="5237" CreationDate="2015-07-22T11:15:11.927" Score="11" ViewCount="388" Body="&lt;p&gt;When you look at a surface pressure chart e.g.:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/WLUEJm.gif&quot; alt=&quot;Weather map&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(from &lt;a href=&quot;http://www.metoffice.gov.uk/public/weather/surface-pressure/#?tab=surfacePressureColour&amp;amp;fcTime=1437480000&quot; rel=&quot;noreferrer&quot;&gt;http://www.metoffice.gov.uk/public/weather/surface-pressure/#?tab=surfacePressureColour&amp;amp;fcTime=1437480000&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;you can see low pressure zones over the North Atlantic ocean. How are these zones tracked? I cannot imagine there are many monitoring stations in the Atlantic ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Possible ways:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Ships - but I doubt there are enough to get readings over a wide enough area.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Comparison of pressure readings from coastal monitoring stations. Are there enough points for accurate interpolation of the readings?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Aircraft - comparison of GPS altitude to barometric pressure readings could give the surface pressure in a given area. That said, most aircraft travelling over the Atlantic are on specified tracks which may not cover a given area.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Monitoring stations on buoys at well spaced locations in the ocean. Potentially impractical and a hazard to shipping.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="3219" LastEditorUserId="192" LastEditDate="2015-07-22T18:28:55.067" LastActivityDate="2015-07-22T18:28:55.067" Title="How are low pressure zones tracked across the ocean?" Tags="|meteorology|barometric-pressure|" AnswerCount="1" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5236" PostTypeId="1" CreationDate="2015-07-22T13:23:21.663" Score="6" ViewCount="612" Body="&lt;p&gt;Note: I'm not at all an expert in this field.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I read in the first few pages of Robein (2010; &lt;a href=&quot;http://bookshop.eage.org/Webshop/product_details.aspx?prod_code=AA0172&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Seismic Imaging, A Review of the Techniques, their Principles, Merits and Limitations&lt;/em&gt;, EAGE&lt;/a&gt;) that both seismic imaging techniques, time and depth migration,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;require an estimate of how fast the seismic waves travel&#xA;  at any given point in the Earth&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But it seems to me that the velocity model would be good enough as an image of the underground and performing excessive processing of the data could mar the quality of the image produced.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Input Marmousi velocity model (already a good image of the underground)&#xA;&lt;a href=&quot;https://i.stack.imgur.com/B7g9n.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/B7g9n.png&quot; alt=&quot;Input Marmousi velocity model&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Output Marmousi image&#xA;&lt;a href=&quot;https://i.stack.imgur.com/MKg1N.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MKg1N.gif&quot; alt=&quot;Output Marmousi image&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3216" LastEditorUserId="28050" LastEditDate="2015-07-22T19:07:06.467" LastActivityDate="2015-07-22T19:16:24.250" Title="Why is it necessary in seismic imaging to calculate an image of reflection coefficients when one of the inputs is the velocity model?" Tags="|geophysics|seismology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5237" PostTypeId="2" ParentId="5235" CreationDate="2015-07-22T13:52:03.990" Score="10" Body="&lt;p&gt;It is a combination of points 1,2 and 4.&lt;/p&gt;&#xA;&lt;h2&gt;Ships&lt;/h2&gt;&#xA;&lt;p&gt;Ships can provide observations, but they are generally confined to shipping lanes rather than distributed all over the oceans.   NOAA operates a volunteer observing program and you can find &lt;a href=&quot;http://www.ndbc.noaa.gov/ship_obs.php&quot; rel=&quot;noreferrer&quot;&gt;recent ship obs here&lt;/a&gt;.  The ships can report location, wind direction, wind speed, pressure, pressure tendency, air temperature, water temperature, dew point, wave information and a few other fields.  Not all ships report all of the data, but pressure is generally reported by all ships participating.&lt;/p&gt;&#xA;&lt;h1&gt;Buoys&lt;/h1&gt;&#xA;&lt;p&gt;NOAA operates a &lt;a href=&quot;http://www.ndbc.noaa.gov/&quot; rel=&quot;noreferrer&quot;&gt;global buoy network&lt;/a&gt; though these are generally located in coastal regions.  There are regions of regularly spaced buoys in the ENSO regions.  There are also some buoys in the Indian Ocean (not pictured).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xjM8Y.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xjM8Y.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;h2&gt;Drifters&lt;/h2&gt;&#xA;&lt;p&gt;The buoy network leaves vast swathes of ocean unmonitored and to get these obs NOAA uses a &lt;a href=&quot;http://www.oco.noaa.gov/surfaceDriftingBuoys.html&quot; rel=&quot;noreferrer&quot;&gt;network of drifters&lt;/a&gt; that, as the name implies, drift along the ocean surface.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TnP5Z.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TnP5Z.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The blue points in the map above are drifters than can report sea level pressure.&lt;/p&gt;&#xA;&lt;h2&gt;Summary&lt;/h2&gt;&#xA;&lt;p&gt;Weather models that assimilate these observations will use sophisticated algorithms to &amp;quot;fill in the gaps&amp;quot; and produce a continuous field of global sea level pressure.&lt;/p&gt;&#xA;&lt;p&gt;Aircraft can report pressure, but knowing pressure at altitude won't yield sea level pressure without knowing (or making assumptions) about the state of the atmosphere between the airplane and the surface.  Upper air observations are good though, and quite important to forecasting and generally much more sparse than ocean surface observations are.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-07-22T13:52:03.990" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5238" PostTypeId="2" ParentId="5236" CreationDate="2015-07-22T19:03:30.030" Score="7" Body="&lt;p&gt;&lt;strong&gt;One of the inputs to seismic processing is a guess at a low-resolution velocity model that is just good enough to build an image. It is not a geologically useful model of acoustic velocities in the earth.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That Marmousi example is a bit misleading, because that seismic section is a synthetic seismogram, simulated from that velocity model (and assuming or modeling rock densities — we need velocity and density to get rock impedance). It is a result of solving the so-called &lt;em&gt;forward problem&lt;/em&gt;$\dagger$ — solving a system of equations representing the seismic experiment, shown here as &lt;strong&gt;G&lt;/strong&gt;, given an earth model &lt;strong&gt;m&lt;/strong&gt;, and getting synthetic seismic data &lt;strong&gt;d&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/llNzF.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/llNzF.png&quot; alt=&quot;Inverse problems&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geophysicists spend most of their time trying to solve the &lt;em&gt;inverse problem&lt;/em&gt; — deriving an earth model &lt;strong&gt;m&lt;/strong&gt; (which is the interesting unknown), given real seismic data &lt;strong&gt;d&lt;/strong&gt; (which we measured), and the parameters of the experiment, our understanding of nature, etc (&lt;strong&gt;G&lt;/strong&gt;). So in a real problem, we wouldn't know that high-resolution velocity model &lt;em&gt;a priori&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;So what was all that about 'requiring an estimate'?&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;We don't go straight from the data to a high-res earth model. First, we have to build a seismic image, via a process called &lt;a href=&quot;https://en.wikipedia.org/wiki/Seismic_migration&quot; rel=&quot;noreferrer&quot;&gt;migration&lt;/a&gt;, which requires us to guess a rough velocity model to focus all the seismic energy into something we can interpret. We do this by choosing a grid of velocity-vs-depth functions that seem to focus well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a pretty typical velocity model for imaging, from a Marmousi example by Tristan van Leeuwen (2012; &lt;a href=&quot;https://www.slim.eos.ubc.ca/Publications/Public/TechReport/2012/vanleeuwen2012smii/vanleeuwen2012smii.pdf&quot; rel=&quot;noreferrer&quot;&gt;UBC preprint&lt;/a&gt;). Notice how it lacks high frequencies:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VuQu8.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VuQu8.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once we have an image, interpreters and seismic analysts can use various methods to reconstruct a plausible model of the earth's impedance. This is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Seismic_inversion&quot; rel=&quot;noreferrer&quot;&gt;seismic inversion&lt;/a&gt;, and is a substantial area of research. It will almost never result in a model with the resolution of the Marmousi model, but we'd like it to be good enough, over enough of the stratigraphy, to be useful.&lt;/p&gt;&#xA;&#xA;&lt;hr /&gt;&#xA;&#xA;&lt;p&gt;$\dagger$ Forward models are useful because we can try to figure out ways to solve the inverse problem better when we already know the answer. Inverse problems are useful because they are a systematic way of making data-constrained inferences about unknowns. Here's some reading on forward and inverse problems:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.agilegeoscience.com/blog/2013/4/10/what-is-inversion.html&quot; rel=&quot;noreferrer&quot;&gt;What is inversion?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.agilegeoscience.com/blog/2013/4/11/how-to-get-paid-big-bucks.html&quot; rel=&quot;noreferrer&quot;&gt;How to get paid big bucks&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.agilegeoscience.com/blog/2013/4/16/backwards-and-forwards-reasoning.html&quot; rel=&quot;noreferrer&quot;&gt;Backwards and forwards reasoning&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2015-07-22T19:16:24.250" LastActivityDate="2015-07-22T19:16:24.250" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5240" PostTypeId="1" CreationDate="2015-07-23T00:11:43.580" Score="8" ViewCount="114" Body="&lt;p&gt;What's the average day of the year when the fewest square miles of the hemisphere's land is covered by snow or ice or transitional forms like slush? Not counting anything below ground like permafrost or uh, temporaryfrost.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe the land minimum is pretty late since North Pole air temps seem to flatline near freezing for ages? That seems to imply there's enough insolation to make it above freezing in the Arctic for quite a while if there was no snow or ice there to chill it by melting. So maybe the last non-permanent snow finally melts in late August or September or something and the ground has like 1-2 weeks before avg temps reach freezing again?&lt;/p&gt;&#xA;" OwnerUserId="3224" LastEditorUserId="3224" LastEditDate="2015-07-24T17:11:02.313" LastActivityDate="2015-07-26T02:55:38.750" Title="When does the Northern Hemisphere reach minimum land area covered by solid H2O?" Tags="|cryosphere|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="5244" PostTypeId="2" ParentId="5211" CreationDate="2015-07-23T22:21:17.317" Score="-6" Body="&lt;p&gt;Some may without basis, dislike this answer, but I believe you will find that the overall pattern of continents coming together, and drifting apart is in direct response to the orbit of the sun around the milky way.  The periodicity matches and there are other tell-tales that add strength to the belief.  I havent heard or found a better explanation for the period of this occurrence.  And one side of the world, seems almost entirely void of continents, adding weight to something one-sided &quot;attracting&quot; the continents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gravity is a wave pattern.  There are those that are looking for it's shape.  But one thing for sure, it has an &quot;interference pattern&quot;.  Please follow this link, and then set the smoothing radius to 25km, and map type &quot;monthly anomalies, then browse, from 2002 through 2014.  If you have experience with wave tables and interference patterns, you will see that there is an interference pattern, which tells you gravity is both coming and going.  Then especially make note of the pattern greenland has in an 11 year cycle... sample  2002, 2007, 2013.  It is obviously &quot;bouncing&quot; as it's pattern and the incoming pattern are running &quot;lateral&quot; to one another.  This happens due to the reversal of the magnetic field of the sun.  The link to the GRACE mission results are here:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://geoid.colorado.edu/grace/dataportal.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA - GRACE Mission Data Analysis Portal Hosted at Colorado U.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;AS a proposed &quot;shape of gravity&quot; I would have you consider this picture.  It is gravity in a neutral &quot;temperment&quot;.:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EUPDf.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EUPDf.gif&quot; alt=&quot;Gravity without imbalances&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sorry i didn't include GRACE's results link the first time round.&lt;/p&gt;&#xA;" OwnerUserId="809" LastEditorUserId="809" LastEditDate="2015-07-26T19:49:31.207" LastActivityDate="2015-07-26T19:49:31.207" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5245" PostTypeId="1" AcceptedAnswerId="5246" CreationDate="2015-07-23T23:43:25.117" Score="5" ViewCount="112" Body="&lt;p&gt;When wildfire acreage is reported, does anyone know if local terrain is taken into consideration, or is the reported acreage the area as viewed on a map? I ask because the two figures are different. A square unit of area on a 30° slope would appear to be .866 square units on a map, whereas a square unit of area on a map would actually be 1.155 units of area on the slope (assuming I've done the math correctly, which I think I have). I'm guessing it's just the area as viewed on a map, because figuring out the average terrain would be pretty difficult, though not impossible.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2015-07-24T00:26:19.147" Title="Wildfire acreage, two dimenional or three?" Tags="|forest|natural-disasters|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5246" PostTypeId="2" ParentId="5245" CreationDate="2015-07-24T00:26:19.147" Score="4" Body="&lt;p&gt;The same issue arises when land is bought and sold. The area used is the flat area from a plan. Slope is not considered because it would require at lot of data because the rate of change of topography and slopes is never uniform. Also the calculations to determine the true area can be convoluted if the change in topography is complex. &lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-07-24T00:26:19.147" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="5247" PostTypeId="1" CreationDate="2015-07-24T04:49:52.627" Score="7" ViewCount="1286" Body="&lt;p&gt;I want to apply seismic colored inversion technique to my datasets. Is there a Matlab code available that I can easily use? Are there any other recommended codes to apply seismic colored inversion?&lt;/p&gt;&#xA;" OwnerUserId="3230" LastEditorUserId="111" LastEditDate="2015-07-27T04:17:51.990" LastActivityDate="2015-08-04T12:56:34.477" Title="Available Matlab code to design Seismic Colored Inversion Operator?" Tags="|geophysics|inversion|seismic|matlab|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5248" PostTypeId="1" AcceptedAnswerId="8748" CreationDate="2015-07-24T19:31:54.490" Score="7" ViewCount="172" Body="&lt;p&gt;In the book of &lt;a href=&quot;https://books.google.com/books?id=-nCHlVuJ4FoC&amp;amp;pg=PA80&amp;amp;source=gbs_toc_r&amp;amp;cad=4#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;nofollow&quot;&gt;Turcotte and Schubert, Geodynamics&lt;/a&gt; I'm trying to solve problem 2.8.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The pressure in the water, in the oceanic crust, and in the mantle beneath the oceanic crust are (from equation 2.19, page 78) is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$p_w = \rho_w g y , \quad  0 \le y \le h_{w}$$&#xA;$$p_{oc} = \rho_w g h_{w} + \rho_{oc} g (y - h_{w}) , \quad  h_{w} \le y \le h_{w}+h_{oc}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$p_m = \rho_w g h_w + \rho_{oc} g h_{oc} + \rho_m g (y-h_w-h_{oc}), \quad  h_w+h_{oc} \le y \le h_{cc}$$&#xA;I should integrate that to find the force at the base of the oceanic crust. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;we know that &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$F=∫_0^b pdy=ρg∫_0^by dy=0.5 ρgb^2$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;so&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$F_m=∫_{h_w+h_{oc}}^{h_{cc}} p_mdy$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;then I tried this&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$F_m=∫_{h_w+h_{oc}}^{h_{cc}}\rho_w g h_w + \rho_{oc} g h_{oc} + \rho_m g (y-h_w-h_{oc})dy$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and it didn't provide the proper result, so i tried to integrate all the pressures:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$F_w=∫_0^{h_{w}}\rho_w g ydy = 0.5 \rho_w g h_{w}^2$$&#xA;$$F_{oc} = ∫_{h_w}^{h_{w}+h_{oc}} \rho_w g h_{w} + \rho_{oc} g (y - h_{w})dy= \rho_w g h_{w}+0.5 \rho_{oc} g (h_{w}+h_{oc})^2 - 0.5 \rho_{oc} g h_{w}^2 - \rho_{oc} g h_{w}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I did the same for the last integral and added them all together: $$F_o = F_w+F_{oc}+F_m$$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;but I still don't get the same final expression as equation 2.20, page 78.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can someone give me a hint to solve the integral? are the limits of my integral correct? Am I adding the right forces together? &lt;/p&gt;&#xA;" OwnerUserId="3161" LastEditorUserId="3161" LastEditDate="2016-02-18T21:21:44.010" LastActivityDate="2016-09-15T17:11:38.197" Title="How to define the force at the base of an oceanic crust" Tags="|geophysics|geodynamics|isostasy|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5249" PostTypeId="2" ParentId="5178" CreationDate="2015-07-24T21:18:10.950" Score="6" Body="&lt;p&gt;This is a big question, but there are benefits and difficulties with all representations, and the efficacy of any coordinate will also depend upon other numerical choices such as the calculation of horizontal pressure gradients [Zängl 2012].  There are broadly two categories: terrain following layers and Cartesian systems such as step terrain and cut cell grids.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Terrain following layers are typically implemented using a coordinate transformation such that the computational domain is rectangular.  There are essentially two choices to make here.  First, the vertical coordinate may be geometric height, pressure, or entropy (potential temperature), or some other monotonic function.  Second, the decay function controls how the influence of the terrain on computational surfaces decays with height: this might be a linear decay (called Basic Terrain Following (BTF) or 'sigma' coordinates [Gal-Chen &amp;amp; Somerville 1975]), or something more elaborate such as Smooth LEvel VErtical (SLEVE) [Schär et al 2002] or Smoothed Terrain Following (STF) [Klemp 2011].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the motivations for smoothing coordinate surfaces is to make horizontal pressure gradient calculations more accurate: in areas of steep terrain metric terms in the coordinate transformation can increase errors [Dempsey &amp;amp; Davis 1998].  This is also one of the motivations for step terrain and cut cell grids, since the grid is orthogonal everywhere except in the cells next to the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another issue with representing terrain is that cells can become very thin (over steep slopes with terrain following layers) or very small (in a cut cell or partial-step grid) which constrains the timestep for explicit numeric methods due to the CFL criteria [Klein 2009].  There are several methods that can overcome this 'small cell problem' [Jebens et al 2011, Yamazaki &amp;amp; Satomura 2010, Steppeler et al. 2002] &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is by no means an exhaustive answer but I hope it gives you some understanding of the issues involved with vertical coordinates.  Additionally, I gave a presentation in 2015 on this topic, the &lt;a href=&quot;http://www.icms.org.uk/downloads/Galerkin/Shaw.pdf&quot; rel=&quot;noreferrer&quot;&gt;slides are available online&lt;/a&gt;.  Another useful review article on nonhydrostatic models, including terrain representation and vertical coordinates, is presented in Steppeler et al 2003.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;References&lt;/h2&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Dempsey, D. and C. Davis, 1998: Error analyses and test of pressure gradient force schemes in nonhydrostatic, mesoscale model. &lt;em&gt;12th Conf. on Numerical Weather Prediction&lt;/em&gt;, Phoenix, AZ. Amer. Meteor. Soc., 236–239&lt;/li&gt;&#xA;&lt;li&gt;Gal-Chen, T. and R. C. Somerville, 1975: On the Use of a Coordinate Transformation for the Solution of the Navier-Stokes Equations. &lt;em&gt;J. Comp. Phys.&lt;/em&gt;, &lt;strong&gt;17&lt;/strong&gt;, 209–228&lt;/li&gt;&#xA;&lt;li&gt;Jebens, S., O. Knoth and R. Weiner, 2011: Partially implicit peer methods for the compressible Euler equations. &lt;em&gt;J. Comp. Phys.&lt;/em&gt;, &lt;strong&gt;230&lt;/strong&gt;, 4955–4974.&lt;/li&gt;&#xA;&lt;li&gt;Schär, C., D. Leuenberger, O. Fuhrer, D. Lüthi and C. Girard, 2002: A new terrain-following vertical coordinate formulation for atmospheric prediction models. &lt;em&gt;Mon. Wea. Rev.&lt;/em&gt;, &lt;strong&gt;130&lt;/strong&gt;, 2459–2480&lt;/li&gt;&#xA;&lt;li&gt;Steppeler, J., H.-W. Bitzer, M. Minotte and L. Bonaventura, 2002: Nonhydrostatic Atmospheric Modeling using a z-Coordinate Representation. &lt;em&gt;Mon. Wea. Rev.&lt;/em&gt;, &lt;strong&gt;130&lt;/strong&gt;, 2143–2149&lt;/li&gt;&#xA;&lt;li&gt;Steppeler, J., R. Hess, U. Schättler and L. Bonaventura, 2003: Review of numerical methods for nonhydrostatic weather prediction models. &lt;em&gt;Meteorology and Atmospheric Physics&lt;/em&gt;, &lt;strong&gt;82&lt;/strong&gt;, 287–301&lt;/li&gt;&#xA;&lt;li&gt;Yamazaki, H. and T. Satomura, 2010: Nonhydrostatic Atmospheric Modeling Using a Combined Cartesian Grid. &lt;em&gt;Mon. Wea. Rev.&lt;/em&gt;, &lt;strong&gt;138&lt;/strong&gt;, 3932–3945&lt;/li&gt;&#xA;&lt;li&gt;Zängl, G., 2012: Extending the numerical stability limit of terrain-following coordinate models over steep slopes. &lt;em&gt;Mon. Wea. Rev.&lt;/em&gt;, &lt;strong&gt;140&lt;/strong&gt;, 3722–3733&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="183" LastEditorUserId="183" LastEditDate="2015-07-25T08:05:34.143" LastActivityDate="2015-07-25T08:05:34.143" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5250" PostTypeId="1" AcceptedAnswerId="5251" CreationDate="2015-07-25T00:20:42.597" Score="6" ViewCount="321" Body="&lt;p&gt;A commenter &lt;a href=&quot;https://news.ycombinator.com/item?id=9930475&quot;&gt;made the following reflection&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Ocean acidification is different than sea level rise and global warming, however. With ocean acidification, we're making an excursion unlike anything the planet has seen in 300 million years. There's simply no precedent that allows us to say &quot;yeah, it's gonna hurt, but the world has already shown that it can cope with this kind of thing&quot;. It hasn't. As far as we know, this level of OA could produce a full trophic collapse -- and that isn't something that even I can't be cavalier about, as it would certainly be a civilisation-limiting (and possibly complex-life-limiting) event. Until we know for certain that the impacts of OA will be less severe than this, we should be doing everything we can to stop and reverse it.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I did High School chemistry. To me it seems that if you have something that is too acidic, then you change the pH by adding a basic (base) solution. (Albeit the reaction may cause some warmth). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But this feels like it is missing something that smarter people than me have spent time thinking through. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: &lt;strong&gt;What is the evidence it is feasible to reverse ocean acidification by adding large quantities of a base (bicarb soda)?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="895" LastEditorUserId="6467" LastEditDate="2020-06-04T20:09:20.110" LastActivityDate="2020-06-04T20:09:20.110" Title="What is the evidence it is feasible to reverse ocean acidification by adding large quantities of a base (bicarb soda)?" Tags="|oceanography|carbon-cycle|geoengineering|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5251" PostTypeId="2" ParentId="5250" CreationDate="2015-07-25T03:47:18.850" Score="7" Body="&lt;p&gt;Instead of using sodium bicarbonate why not use limestone instead? Limestone is already used on an industrial scale to neutralise acids and acidic solutions. Also, sodium bicarbonate needs to be manufactured, whereas limestone just needs to be dug up. The manufacturing of sodium bicarbonate would unnecessarily use energy and potentially create more carbon dioxide if it were to be used to neutralise the worlds oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Danny Harvey of the University of Toronto has already looked into &lt;a href=&quot;http://www.whoi.edu/cms/files/HARVEY_Scripps_Ocean_Acidification_28205.ppt&quot;&gt;this&lt;/a&gt;. His solution is to deposit 4 Gt/a of limestone into the oceans. To put this in perspective, &lt;a href=&quot;http://www.worldcoal.org/resources/coal-statistics/&quot;&gt;global coal production in 2013&lt;/a&gt; was nearly double this at 7.823 Gt and it is more than &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_countries_by_iron_ore_production&quot;&gt;global iron ore production in 2014&lt;/a&gt; of 3.22 Gt. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mining of so much limestone would be a massive and expensive undertaking. Then there are the added costs of grinding the limestone to $40 \mu m$, as specified by Danny Harvey. Added to this would be the cost of depositing the finely ground limestone to the oceans. Because the limestone could not be expected to be dumped at one coastal location and then disperse globally, this would require a fleet of ships to deposit the limestone all over the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other things to consider include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Are there sufficient quantities of easily obtainable limestone to do&#xA;this?&lt;/li&gt;&#xA;&lt;li&gt;What would such a use of limestone do to the supply and cost of&#xA;cement, used for construction, etc.?&lt;/li&gt;&#xA;&lt;li&gt;What impact would such a huge annual deposition of limestone have of&#xA;ocean life forms and biodiversity?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The other thing that Danny Harvey states in his document is that 4 Gt of limestone would need to be deposited in the oceans annually for at least 200 years for &quot;a modest additional benefit&quot;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2015-07-25T06:43:24.607" LastActivityDate="2015-07-25T06:43:24.607" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5252" PostTypeId="2" ParentId="5228" CreationDate="2015-07-25T04:17:16.623" Score="3" Body="&lt;p&gt;The references you and @farrenthrope cited (or a good introductory mineralogy text) should have answers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In brief:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The crystallographic class is significant to mineralogy because it is direct result of the mineral's crystalline lattice (its most fundamental property.) Each mineral can belong to only one crystallographic class.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;How can I determine the [crystallographic] class an [unidentified] mineral [specimen] falls under?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You'll need to inspect your specimen and try to recognize the symmetry operations (like rotations and reflections) present in some physical properties of your specimen, commonly the symmetry of euhedral crystal habit, the symmetry of optical properties, or the symmetry of an x-ray diffraction pattern etc. Each crystallographic class is defined by a unique set of symmetry operations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;How were the 32 classes determined?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A combination of observation and mathematics. The law of rational indices was deduced by Haüy (1784, 1801) from the observation of the stacking laws required to build the natural faces of crystals by piling up elementary blocks, for instance cubes to construct the faces of the rhomb-dodecahedron observed in garnets or the pentagon-dodecahedron observed in pyrite, or rhombohedrons to construct a scalenohedron of calcite. Hessel (1830) proved that, as a consequence of the law of rational intercepts, morphological forms can combine to give exactly 32 kinds of crystal symmetry in Euclidean space, since only two-, three-, four-, and six-fold rotation axes can occur.&lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2015-07-25T04:17:16.623" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5253" PostTypeId="1" AcceptedAnswerId="5254" CreationDate="2015-07-25T15:10:09.887" Score="19" ViewCount="3611" Body="&lt;p&gt;I was recently on a long-haul flight over Siberia and it struck me as rather remarkable that something like the &lt;a href=&quot;https://en.wikipedia.org/wiki/Lena_River&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lena River&lt;/a&gt; could exist. It seems very surprising that there's a route from some random spot near Lake Baikal over 2,800 miles or so to the Arctic Ocean, which is downhill all the way. Likewise, the Missouri River tells us that there's an even longer downhill-only route from some place in Montana to the Gulf of Mexico.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But these things certainly do exist and it's a pattern repeated all over the world: the great majority of the Earth's surface is drained by rivers that run downhill to the sea. They don't get stuck and they don't seem to form huge numbers of lakes where they have to flood an area to raise the water level over some barrier. I'm aware of &lt;a href=&quot;https://en.wikipedia.org/wiki/Endorheic_basin&quot; rel=&quot;nofollow noreferrer&quot;&gt;endorheic basins&lt;/a&gt;, which don't drain to the ocean but they only cover about 18% of the land surface, mostly in central Asia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the existence of long downhill routes more likely than I imagined? (I can't tell if I think it's more likely in mountainous areas than in flatter areas, which suggests I have poor intuition about this) Or is it just a coincidence of our planet? Did the rivers make the downhill paths themselves? &lt;/p&gt;&#xA;" OwnerUserId="240" LastEditorUserId="6298" LastEditDate="2017-11-07T23:19:52.427" LastActivityDate="2017-11-07T23:19:52.427" Title="How do long rivers exist?" Tags="|hydrology|rivers|geomorphology|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="5254" PostTypeId="2" ParentId="5253" CreationDate="2015-07-25T16:48:04.147" Score="16" Body="&lt;p&gt;Well, I can only agree that it is indeed amazing and it doesn't get less amazing when some geology, hydrology and geomorphology is added to the the amazement. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;All precipitation that falls on land must flow back to the oceans somehow, and unless it evaporates it will flow in rivers or as groundwater towards a lower hydrostatic level. Water can not flow uphill, so it follows (and crafts) the slope in topography. Water will flow from mountains towards the ocean and due to geometric and morphological reasons, rivers joint to &lt;a href=&quot;https://en.wikipedia.org/wiki/Drainage_system_%28geomorphology%29&quot; rel=&quot;noreferrer&quot;&gt;a drainage pattern&lt;/a&gt; due to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Fluvial&quot; rel=&quot;noreferrer&quot;&gt;geology and topography.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mountain ranges are often formed from orogeny, where tectonic plates collide. Rivers starts at high altitude, radiating out in all directions from mountains, but as collisions in the present continental settings are often on the rim of large plates (e.g Andes, Alps, Himalaya), and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Drainage_divide&quot; rel=&quot;noreferrer&quot;&gt;rivers can't cross the range&lt;/a&gt;, it will have to travel the whole continental plate to reach ocean level. In the case of Asia, most large rivers starts in Himalaya (or other tectonic active regions, as Altai), in Europe large rivers starts in the Alps. In Africa, they start in the tectonic active rift zone. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This map shows the ocean drainage dividers. The border between the drainage areas are the line where rivers start. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XYDww.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XYDww.png&quot; alt=&quot;&amp;quot;Ocean drainage&amp;quot; by Citynoise at English Wikipedia - Transferred from en.wikipedia to Commons.. Licensed under Public Domain via Wikimedia Commons - https://commons.wikimedia.org/wiki/File:Ocean_drainage.png#/media/File:Ocean_drainage.png&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lakes could be understood as temporary stop in the flow, and it will quickly fill up with vegetation and sediments as the velocity of the water decreases. In a geologic context, lakes are never very old, Baikal being the oldest, 25 million years. Drainage patterns are often much older. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So why are some rivers so long? Because of tectonic uplifts and orogenies. The answer to your question 'Did the rivers make the downhill paths themselves?' is yes, as erosion works toward the peneplain (low relief). &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2015-07-25T20:00:49.243" LastActivityDate="2015-07-25T20:00:49.243" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="5255" PostTypeId="1" AcceptedAnswerId="5257" CreationDate="2015-07-25T17:59:41.597" Score="17" ViewCount="19265" Body="&lt;p&gt;At 9:30 PM on July 13, 2015, I was looking due south from Oshkosh, WI. I saw very clearly a large storm with 1-2 lightning strikes per second. I could see cloud-to-cloud lightning traces, as well as the cloud lit up from within.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looking at the radar, the only storm in that direction was near Rockford, IL, 125 miles away as the crow flies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it possible to see the top of a thunderstorm from that far away?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Yk1Qb.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Yk1Qb.png&quot; alt=&quot;Weather radar July 13, 2015&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3232" LastActivityDate="2019-08-03T16:36:08.187" Title="How far away can you see a thunderstorm?" Tags="|meteorology|thunderstorm|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5256" PostTypeId="1" CreationDate="2015-07-25T22:43:12.910" Score="3" ViewCount="35" Body="&lt;p&gt;What are the impacts of pollutants from North America and elsewhere on Arctic wildlife?&lt;/p&gt;&#xA;" OwnerUserId="3207" LastEditorUserId="111" LastEditDate="2015-07-26T02:11:32.110" LastActivityDate="2015-07-26T02:11:32.110" Title="What are the impacts of pollutants from North America and elsewhere on Arctic wildlife?" Tags="|oceanography|human-influence|pollution|arctic|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5257" PostTypeId="2" ParentId="5255" CreationDate="2015-07-25T22:49:01.503" Score="14" Body="&lt;p&gt;The top of a cumulonimbus cloud is usually about 40,000 feet and can reach heights of over 60,000 feet, which would be visible for a distance of 245 or 300 miles, respectively.  Of course, that would be the very top that would be visible at those distances, but it puts it well within the 125 mile distance from which you saw the storm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following formula was used:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\text{distance} = 3958.8 * \arccos(3958.8/(3958.8+\text{height}))$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$3958.8 \ \mathrm{mi}$&lt;/span&gt; is the mean radius of earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This formula calculates the distance from an observer to the horizon, which for a six-foot tall person is close enough. If you wanted to calculate the distance an object would be visible from (given absolute atmospheric clarity) you'd have to calculate this twice (from observer to horizon and horizon to object) and add the results.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastEditorUserId="20" LastEditDate="2019-08-03T16:36:08.187" LastActivityDate="2019-08-03T16:36:08.187" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="5258" PostTypeId="2" ParentId="5240" CreationDate="2015-07-26T02:55:38.750" Score="3" Body="&lt;p&gt;A little Google searching and I found this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TiHmR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TiHmR.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source:  &lt;a href=&quot;https://nsidc.org/cryosphere/sotc/snow_extent.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://nsidc.org/cryosphere/sotc/snow_extent.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Snow-cover is considered an important factor in climate change study, so it's tracked pretty carefully.   There's probably a specific average minimum date out there somewhere if you're really interested but I didn't see it.  Judging from the chart, somewhere around mid August.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sea ice cover is later, that reaches a minimum in September most years, but oceans are slower to change than land and air, so that should be expected.   The hottest day on average, if you care about that, is July 24.   &lt;a href=&quot;http://m.weatherbug.com/weather-news/weather-reports/5225&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://m.weatherbug.com/weather-news/weather-reports/5225&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2015-07-26T02:55:38.750" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5259" PostTypeId="1" AcceptedAnswerId="5261" CreationDate="2015-07-26T07:58:47.963" Score="7" ViewCount="2010" Body="&lt;p&gt;I have downloaded the sea surface temperature data from the Ocean Color website, the file is in NetCDF format and contains no of geophysical_data variables like &lt;code&gt;sst&lt;/code&gt;, &lt;code&gt;qual_sst&lt;/code&gt;, &lt;code&gt;flag_sst&lt;/code&gt;, &lt;code&gt;bias_sst&lt;/code&gt;, etc.&#xA;I used the following MATLAB code for file read and it is giving me an error: &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;temp=ncread('A2014213085500.L2_LAC_SST.x.nc','sst') &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Error:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Error using internal.matlab.imagesci.nc/getGroupAndVarid (line 2075)&#xA;Could not find variable or group 'sst' in file.&#xA;&#xA;Error in internal.matlab.imagesci.nc/read (line 593)&#xA;        [gid, varid] = getGroupAndVarid(this, location);&#xA;&#xA;Error in ncread (line 58)&#xA;vardata = ncObj.read(varName, varargin{:});&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Can someone tell me what is the cause of the error?&lt;/p&gt;&#xA;" OwnerUserId="3235" LastEditorUserId="192" LastEditDate="2015-07-26T21:50:49.400" LastActivityDate="2015-07-26T21:50:49.400" Title="How to read a NetCDF4 file in Matlab?" Tags="|oceanography|matlab|netcdf|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5260" PostTypeId="2" ParentId="5129" CreationDate="2015-07-26T13:33:37.367" Score="4" Body="&lt;p&gt;The inverted barometer (IB) is a static (isostatic) response of the oceans to atmospheric pressure. The basic equation is&#xA;IB = -(change in pressure) / [(seawater density)*(acceleration due to gravity)] &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Its an inverse relation i.e. with increase in pressure the sea level goes down and vice versa. In simple terms, 1 mbar decrease in atmospheric pressure with result in 1 cm increase in sea level.&lt;/p&gt;&#xA;" OwnerUserId="3236" LastActivityDate="2015-07-26T13:33:37.367" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5261" PostTypeId="2" ParentId="5259" CreationDate="2015-07-26T13:48:31.413" Score="6" Body="&lt;p&gt;These days I use: &lt;a href=&quot;https://code.google.com/p/nctoolbox/wiki/ncgeodataset&quot;&gt;ncgeodataset&lt;/a&gt;. The routine allows for the extraction of a subset of data without having to load the entire file or even an array into Matlab. It is great for large datasets.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-07-26T13:48:31.413" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5262" PostTypeId="1" CreationDate="2015-07-27T11:09:50.270" Score="8" ViewCount="114" Body="&lt;p&gt;In Scotland, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Caledonian_Forest&quot;&gt;Caledonian Forest&lt;/a&gt; has been cut down by humans.  According to an unsourced Wikipedia article the &lt;a href=&quot;https://en.wikipedia.org/wiki/Tree_line&quot;&gt;tree line&lt;/a&gt; in Scotland is at 500 metre (it does not indicate the tree line elevation difference between southeast and northwest Scotland, which should be considerable).  That means considerable areas are &lt;em&gt;naturally&lt;/em&gt; bare, and therefore arguably less unnatural than the areas where forests have been cleared.  When I pass through Scotland, is there a way to tell whether the spot I stand on had a forest before that was cleared, or that it is a naturally bare area?&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2015-07-27T13:14:02.910" Title="Is there a way to tell whether land is cleared from forest, or naturally bare?" Tags="|forest|deforestation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5264" PostTypeId="2" ParentId="5262" CreationDate="2015-07-27T13:14:02.910" Score="2" Body="&lt;p&gt;Just by looking at a treeless region it would be difficult to know whether it was naturally treeless or whether the lack of trees was due to human actions. The history of the region would need to be known.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Scotland, due to the extent of glaciation during the last ice age some of the ground was scoured, leaving bare rock when the ice finally melted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With soil removed there is little opportunity for trees to develop deep roots and establish forests.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Loss of soil can result from natural causes and human actions. The area around &lt;a href=&quot;https://en.wikipedia.org/wiki/Queenstown,_Tasmania&quot; rel=&quot;nofollow&quot;&gt;Queenstown, Tasmania&lt;/a&gt;, in Australia is now denuded of trees due to a combination of logging and sulfuric acid rain from smelter fumes that killed the then existing trees followed by heavy rainfall washing away the soil from the steep terrain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the best ways to tell if an area is naturally bare is to leave it allow for at least several decades so that no humans can do anything to it. If trees naturally return to the area, that area once was capable of having a forest. If trees do not grow, the area either never had a  forest  or it has been so badly degraded that  trees can no longer grow there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Despite the environment carnage experienced by Queenstown, Tasmania during the 19th and 20th centuries and the subsequent lack  of soil, if left alone, trees will try to grow in the area.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-07-27T13:14:02.910" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5265" PostTypeId="5" CreationDate="2015-07-27T17:58:33.490" Score="0" Body="&lt;p&gt;NetCDF (Network Common Data Form) is a set of software libraries and self-describing, machine-independent data formats that support the creation, access, and sharing of array-oriented scientific data. The project homepage is hosted by the Unidata program at the University Corporation for Atmospheric Research (UCAR). They are also the chief source of netCDF software, standards development, updates, etc. The format is an open standard. NetCDF Classic and 64-bit Offset Format are an international standard of the Open Geospatial Consortium.&lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2015-07-27T19:19:09.640" LastActivityDate="2015-07-27T19:19:09.640" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5266" PostTypeId="4" CreationDate="2015-07-27T17:58:33.490" Score="0" Body="NetCDF (Network Common Data Form) is a self-describing data format developed by University Corporation for Atmospheric Research (UCAR)." OwnerUserId="192" LastEditorUserId="192" LastEditDate="2015-07-27T19:19:14.533" LastActivityDate="2015-07-27T19:19:14.533" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5267" PostTypeId="1" CreationDate="2015-07-28T02:57:59.990" Score="19" ViewCount="3025" Body="&lt;p&gt;First off, a confession:  I'm asking this question because of &lt;em&gt;The Lord of the Rings&lt;/em&gt;.  If you're not aware already, in the story, a magical ring can only be destroyed in a specific volcano.  The reason for this is presumably &quot;because magic&quot;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the issue got me wondering if this volcano is any different from every other volcano on the planet.  Is there a significant difference between the magma in different volcanoes?  If so, why?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Doesn't all magma come from the same place if you go down deep enough?&lt;/p&gt;&#xA;" OwnerUserId="3240" LastEditorUserId="3240" LastEditDate="2015-07-28T20:07:41.630" LastActivityDate="2020-08-02T07:27:17.327" Title="Is the magma in one volcano different from the magma in every other volcano?" Tags="|geology|volcanology|geochemistry|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5268" PostTypeId="2" ParentId="5267" CreationDate="2015-07-28T04:01:57.460" Score="16" Body="&lt;p&gt;In keeping with your &lt;em&gt;Lord of the Rings&lt;/em&gt; inspiration, the &lt;a href=&quot;http://www.teara.govt.nz/en/interactive/8686/types-of-magma&quot; rel=&quot;nofollow&quot;&gt;first reference&lt;/a&gt; is from New Zealand, where the &lt;em&gt;Lord of the Rings&lt;/em&gt; movies were made.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are three main types of magma that volcanoes currently produce: basalt, andesite and rhyolite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Basalt magma&lt;/strong&gt; has a high temperature, around 1200ºC, it is poor in silica, has a low viscosity and a low gas content. When basalt erupts it produces a flowing magma.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Andesite magma&lt;/strong&gt; has a mid range temperature, between 800ºC and 1000ºC, it also has a mid range silica content and moderate viscosity and gas content. When andesite erupts it flows but it is also moderately explosive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Rhyolite magma&lt;/strong&gt; has a low temperature, between 750ºC and 850ºC, it is silica rich and it has a very high viscosity and high gas content. When it erupts it is very explosive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other forms of &lt;a href=&quot;https://en.wikipedia.org/wiki/Magma&quot; rel=&quot;nofollow&quot;&gt;magma&lt;/a&gt; which are much rarer are carbonatite melts and komatiite melts. &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonatite&quot; rel=&quot;nofollow&quot;&gt;Carbonatite&lt;/a&gt; melts may be cool, as low as 600ºC, whereas &lt;a href=&quot;https://en.wikipedia.org/wiki/Komatiite&quot; rel=&quot;nofollow&quot;&gt;komatiite&lt;/a&gt; may have been as hot as 1600ºC. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unlike the other forms of magma that are composed of silicate minerals, carbonate melts are composed of carbonates and can be confused with marble and may have to be geochemically analysed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most komatiites are very old, up to  4 billion years old. It is speculated that komatiite magma formation was possible when the Mantle was at least 500ºC hotter.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="28050" LastEditDate="2015-07-28T19:56:58.763" LastActivityDate="2015-07-28T19:56:58.763" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5269" PostTypeId="1" CreationDate="2015-07-27T06:08:57.350" Score="10" ViewCount="1176" Body="&lt;p&gt;I requested satellite image data (GVAR_IMG) for a project that I am working on from the GOES satellite, but I don't know what format it's in or how to read it.  When I open it with a text editor it is hexadecimal.  The files are end in .BAND_01, .BAND_02, etc.  &lt;a href=&quot;http://www.class.ngdc.noaa.gov/saa/products/welcome&quot;&gt;The website that I requested the data&lt;/a&gt; from said that the data is available in different formats: &quot;Data distribution formats available are raw, AREA, NetCDF, GIF, and JPEG.&quot; However, I do not see the option for selecting different formats.&lt;/p&gt;&#xA;" OwnerUserId="3247" OwnerDisplayName="scottlittle" LastEditorUserId="725" LastEditDate="2017-03-22T06:24:35.490" LastActivityDate="2017-03-22T06:24:35.490" Title="How to read NOAA/NASA GOES satellite data?" Tags="|software|data-formats|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5270" PostTypeId="2" ParentId="5269" CreationDate="2015-07-28T16:53:25.450" Score="5" Body="&lt;p&gt;Go to the &lt;a href=&quot;http://www.class.ngdc.noaa.gov/saa/products/user_preferences&quot; rel=&quot;nofollow&quot;&gt;user preferences&lt;/a&gt;.  From there you will be able to choose different formats and data options.  If you choose netCDF, you will be able to read these filetypes with most map readers.  For Python, you can use netCDF4-python.&lt;/p&gt;&#xA;" OwnerUserId="3247" LastEditorUserId="3247" LastEditDate="2015-08-05T07:55:38.627" LastActivityDate="2015-08-05T07:55:38.627" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="5271" PostTypeId="2" ParentId="4896" CreationDate="2015-07-28T17:51:46.337" Score="5" Body="&lt;p&gt;There are several reasons why the ocean floor is not a pool of liquid $\ce{CO_2}$:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Solubility of gaseous $\ce{CO_2}$ in brine is low.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Mass transfer of gaseous $\ce{CO_2}$ from the atmosphere is slower than the time to react with water to make carbonate/bicarbonate&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Carbonate/bicarbonate act as a buffer for atmospheric $\ce{CO_2}$ precipitating and dissolving as atmospheric $\ce{CO_2}$ fluctuates.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Liquid $\ce{CO_2}$ at the ocean floor must have a source of pure enough $\ce{CO_2}$ to liquefy and it must be in enough abundance, at a high enough pressure, so that it is not diluted or mixed with water or brine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data above shows that this has happened somewhere in the world... that is cool.&lt;/p&gt;&#xA;" OwnerUserId="3249" LastEditorUserId="28050" LastEditDate="2015-07-28T19:54:15.030" LastActivityDate="2015-07-28T19:54:15.030" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5274" PostTypeId="2" ParentId="5267" CreationDate="2015-07-29T12:35:16.730" Score="4" Body="&lt;p&gt;Let's make this question more fun. What type of magma is required to destroy the One Ring?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For that we need to know what it is made of. According to &lt;a href=&quot;https://scifi.stackexchange.com/questions/12949/what-material-was-the-one-ring-made-of&quot;&gt;&quot;What material was the One Ring made of?&quot;&lt;/a&gt;, it is made of gold. But that's boring - gold is easy to melt. The melting point is about 1000 °C, which is less than some of erupted magmas (basalt for example).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ring is somewhat yellow, so it has to have at least some gold in it. How about we make an alloy of gold and any other noble metal? An alloy of 50-50 gold and palladium will melt at around 1400 °C. A 50-50 alloy of gold and ruthenium or rhodium will melt above 2000 °C! That's definitely going to require a very hot volcano that doesn't exist on Earth, and probably never did.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So let's assume that it is a certain alloy of gold and something else and we have a really hot volcano that can melt it. That's still no good - we're just going to have a molten blob of ring in our magma. What we really want is to dissolve the ring in the magma, to destroy it completely. For example, if you take table salt you can heat it up to 800 °C and melt it. That's no good - you still have salt, just liquid. A better way would be to stick it in water, and it's gone forever (as long as the water is there, that is). Now this is where it gets hard. Noble metals are notoriously known for not being soluble in magmas. Let's think of some processes that can do it:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Have an oxidising magma. Noble metal solubility in magmas increases with their oxidation state. Oxidising magmas, for example where you would find magnetite, can dissolve more metals in them. This could work, but I find this rather boring.&lt;/li&gt;&#xA;&lt;li&gt;Have a hydrous peralkaline (i.e. a magmas with loads of sodium in it) magma with chlorine and fluorine. This stuff can dissolve everything, and that's why we mine them for rare metals, for example in Greenland and Canada. The problem is that according to LoTR, this is also the volcano where the ring was forged (and for now, also where the metals came from). Peralkaline hardly have any noble metals in them to begin with, so that's not a good option.&lt;/li&gt;&#xA;&lt;li&gt;Our best bet is to throw it in a sulphide magma (in contrast to the &quot;regular&quot; silicate magmas such as basalt etc). Sulphide magmas are excellent in dissolving noble metals. Have a pool of that, throw in the ring, and it's gone for good. The problem is that we don't have these kinds of magmas in volcanos. They always form together with silicate magmas, and they are much denser. They sink down whereas the boring silicate magma floats to the volcano's lava lake. However, because our ring is also denser than the silicate magma, it's going to sink down. This will happen faster in basaltic magmas. Basaltic magmas are also more likely to have a sulphide melt associated with them! What's even better is that noble metals are usually mined from these exact sulphide ore deposits. It all fits in!&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;So to answer your question - there are loads of magma types. The one that has the highest chance of destroying the One Ring is a basaltic magma with a conjugate immiscible sulphide melt phase. Good luck!&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:43:40.883" LastActivityDate="2016-10-07T04:00:11.307" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5275" PostTypeId="2" ParentId="5267" CreationDate="2015-07-29T19:49:04.943" Score="5" Body="&lt;p&gt;Because of variations in temperature, depth of emplacement, thickness of the crust, heterogeneity in the mantle, and variations in the magma distillation process, each volcano has a unique geochemical signature.  However, volcanoes in similar tectonic settings have similar geochemistry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geochemistry of magma starts out as ultramafic when sourced from the mantle.  However, the mantle is not entirely homogeneous, which is evident from the presence of hot spots and other thermal and gravitational variations.  Ultramafic magma rising from the solid mantle can be generated by decompression (thinning of the crust) or by the introduction of a contaminant (water from subducting plates).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once the mantle melt reaches the base of the crust, it's geochemistry can change via three different processes:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;strong&gt;Crystal settling&lt;/strong&gt; - various mineral have differing melting/solidifying temperatures, allowing for a process of distillation where magma can gradually be made more felsic (from basalt-like to rhyolite-like)&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Inclusion of country rock&lt;/strong&gt; (aka assimilation) - where crustal material is incorporated and melted into the magma&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Partial melting&lt;/strong&gt; - where only the part of the rock material is melted&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Crystal settling and partial melting follow the Bowen's reaction series (pictured), which tells you which minerals melt at which temperatures.  This is essentially the same process of distillation of alcohol by separating it from water, which has a lower temperature of vaporization.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each of these processes allows for a unique rock chemistry, even within the same batholith.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While we categorize magmas into different groups based on their geochemistry, we must keep in mind that the geochemistry of any igneous rock falls along a sliding (not discrete) scale (i.e. not every granite is the same).  Otherwise igneous petrology would be really easy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See the &lt;a href=&quot;https://en.wikipedia.org/wiki/Igneous_differentiation&quot; rel=&quot;noreferrer&quot;&gt;wikipedia article on igneous differentiation&lt;/a&gt; for more information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JyZn9.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JyZn9.png&quot; alt=&quot;Bowen&amp;#39;s Reaction Series&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="510" LastActivityDate="2015-07-29T19:49:04.943" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5276" PostTypeId="1" CreationDate="2015-07-29T20:49:22.953" Score="15" ViewCount="671" Body="&lt;p&gt;According to &lt;a href=&quot;http://www.livescience.com/17324-dead-sea-completely-vanish.html&quot;&gt;recent&lt;/a&gt; &lt;a href=&quot;http://adsabs.harvard.edu/abs/2011AGUFMPP11C..05G&quot;&gt;findings&lt;/a&gt;, during the last interglacial period, about 120,000 years ago, the precursor of the Dead Sea (Lake Lisan) dried up perhaps entirely. Today, the Dead Sea level is dropping at rates of around &gt;1m/year from the countries surrounding the Sea using all the runoff. Future climate change scenarios for the region suggest even more arid conditions. Even though previous studies suggested that the decrease in water level would stabilize around 100-150 m below current conditions, the &lt;a href=&quot;http://adsabs.harvard.edu/abs/2011AGUFMPP11C..05G&quot;&gt;Goldstein et al. (2011)&lt;/a&gt; core evidence might suggest otherwise. &#xA;Could the Dead Sea dry up? What conditions could lead to such an extreme? When would that occur?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2015-07-30T11:31:50.003" LastActivityDate="2015-10-07T16:01:36.053" Title="Could the Dead Sea dry up? and if so, when?" Tags="|climate-change|hydrology|sea-level|drought|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5277" PostTypeId="1" AcceptedAnswerId="5278" CreationDate="2015-07-30T04:06:57.433" Score="11" ViewCount="328" Body="&lt;p&gt;Since rocks can have magnetic signatures, as is the case with paleomagnetism, can they store past pressures also? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, when researchers are trying to determine past ocean levels, they usually look at isotopes. But is there any way they can look at rock morphology to see how high sea levels may have been (maybe a more compressed rock meant higher pressures, meaning higher sea levels and vice versa)?&lt;/p&gt;&#xA;" OwnerUserId="3181" LastEditorUserId="725" LastEditDate="2015-07-30T11:49:35.550" LastActivityDate="2019-02-18T13:01:43.033" Title="Can rocks have pressure signatures?" Tags="|geophysics|geology|oceanography|sea-level|rocks|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5278" PostTypeId="2" ParentId="5277" CreationDate="2015-07-30T12:07:25.177" Score="8" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Since rocks can have magnetic signatures, as is the case with paleomagnetism, can they store past pressures also?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes, but not directly, and it is very hard to know the exact pressure (in contrast with paleomagnetism where you can actually get a nice number).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One way to do it is to simply look at the minerals you have in the rock. Some minerals exist only in a certain range of pressures. The best and most known example is the two polymorphs of carbon: graphite and diamond. If you find a rock with diamonds in it then you know that (at least the diamonds) formed at great depth. There are many other mineral transformations that depend on pressure. Andalusite is low pressure whereas kyanite is high pressure. Plagioclase is low pressure, spinel is intermediate pressure and garnet is high pressure. You can look up images of those minerals for some eye candy! Note that I'm using the words &quot;low&quot; and &quot;high&quot; quite vaguely, as everything is relative and the exact numbers are not important for this case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another way of finding the pressure of a rock formation is by using the chemical compositions of the minerals in it. This is basically an improved version of the previous method. Instead of having a certain mineral assemblage transform to a second assemblage, we take two coexisting minerals. If we know how a certain element (for example magnesium or aluminum or whatever) behaves in a certain fashion relative to the pressure, we can measure that element in both minerals and find out the pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A third way is to look at a thing called fluid inclusions. These are tiny bubbles of liquid or gas (or something in between, the distinction may be fuzzy at high pressures and temperatures), trapped in a mineral when it was forming. This is essentially a tiny pressure vessel, so using all kinds of methods we can figure out what was the pressure during that time. Here's a picture of how it looks under the microscope:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LgCpR.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LgCpR.jpg&quot; alt=&quot;fluid inclusion&quot;&gt;&lt;/a&gt;&#xA;&lt;sup&gt;source: &lt;a href=&quot;http://rohmin.unileoben.ac.at/de/3388/&quot; rel=&quot;noreferrer&quot;&gt;http://rohmin.unileoben.ac.at/de/3388/&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;But is there any way they can look at rock morphology to see how high sea levels may have been?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not using these methods. The problem is sensitivity. I was talking to you about diamond and graphite - this is extremely deep in the Earth. The pressure of adding a few metres of ocean on top of it are definitely not even going to tickle that transformation. Furthermore, for this to actually be effective, the rocks have to be directly on the seafloor. Once you start burying them in the sediment, you have additional pressure on top of them. A general rule of thumb is 100 metres of additional rock pressure equal 300 metres of water pressure. How would you know how much rock was on top of it? And as the rock gets buried deeper, how would you know what time frame your measurement represents?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in short, no. We can't do it. There are, however, other methods of figuring out sea levels without using pressures.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-07-30T12:07:25.177" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5281" PostTypeId="2" ParentId="5277" CreationDate="2015-07-31T12:32:15.573" Score="5" Body="&lt;p&gt;Recorded pressures in rock would be a very useful measurement for multiple fields of geology. There are many answers to this question that depend on different types of rocks and processes. In general though, because rocks are elastic, pressure, which is a force per unit area, will cause stress on a rock. This stress, if applied at a low temperature and pressure, will compress the rock, temporarily deforming it. When the stress is released, the rock will return to its pre-stressed state. If this stress is applied over a long period of time and at a high enough temperature and pressure, the rock will eventually deform permanently. This deformation is called strain and it can be related to stress using Hooke's law:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\sigma_{ij} = C_{ijkl} \epsilon_{kl}&#xA;$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$\sigma$&lt;/span&gt; is stress, &lt;span class=&quot;math-container&quot;&gt;$\epsilon$&lt;/span&gt; is strain, and &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; is the compliance tensor. We can directly measure strain on rocks using lab tests such as a tri-axial stress test with cored rock. For this test, you apply a specified uniform or directional stress to a rock and measure the strain. These tests show the empirical relationship between stress and strain for different rocks:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pm9OA.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pm9OA.jpg&quot; alt=&quot;Validhtml&quot; /&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;source: &lt;a href=&quot;http://jolisfukyu.tokai-sc.jaea.go.jp/fukyu/mirai-en/2010/2_9.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://jolisfukyu.tokai-sc.jaea.go.jp/fukyu/mirai-en/2010/2_9.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;You asked about measuring sea level fluctuations; this type of pressure would apply a hydrostatic stress on the rocks. However, this stress would not be sufficient to cause permanent deformation in rocks. Therefore we (in O&amp;amp;G) generally rely on sequence stratigraphy to measure sea level fluctuations during a certain time period.&lt;/p&gt;&#xA;&lt;p&gt;Here are some basic definitions of terms I used in this answer. Hope this helps!&#xA;&lt;a href=&quot;https://www.uwgb.edu/dutchs/structge/stress.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.uwgb.edu/dutchs/structge/stress.htm&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3256" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-02-18T13:01:43.033" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="5282" PostTypeId="1" AcceptedAnswerId="5292" CreationDate="2015-07-31T12:40:10.837" Score="9" ViewCount="1233" Body="&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/5250/what-is-the-evidence-it-is-feasible-to-reverse-ocean-acidification-by-adding-lar&quot;&gt;This question&lt;/a&gt; asked: &lt;strong&gt;What is the evidence it is feasible to reverse ocean acidification by adding large quantities of a base (bicarb soda)?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/5251/895&quot;&gt;The result&lt;/a&gt; was: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Danny Harvey of the University of Toronto has already looked into &lt;a href=&quot;http://www.whoi.edu/cms/files/HARVEY_Scripps_Ocean_Acidification_28205.ppt&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;. His solution is to deposit 4 Gt/a of limestone into the oceans. To put this in perspective, &lt;a href=&quot;http://www.worldcoal.org/resources/coal-statistics/&quot; rel=&quot;nofollow noreferrer&quot;&gt;global coal production in 2013&lt;/a&gt; was nearly double this at 7.823 Gt and it is more than &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_countries_by_iron_ore_production&quot; rel=&quot;nofollow noreferrer&quot;&gt;global iron ore production in 2014&lt;/a&gt; of 3.22 Gt.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The respondent then posed the question: &lt;em&gt;Are there sufficient quantities of easily obtainable limestone to do this?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: &lt;strong&gt;Are there sufficient quantities of limestone to dump in the ocean to reverse acidification?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="895" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-11-08T06:34:55.410" Title="Are there sufficient quantities of limestone to dump in the ocean to reverse acidification?" Tags="|ocean|oceanography|biogeochemistry|limestone|mining|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5283" PostTypeId="1" CreationDate="2015-07-31T13:07:51.017" Score="2" ViewCount="1199" Body="&lt;p&gt;What are the effects of &quot;day&quot; and &quot;night&quot; on natural environment,including life of humans,animals,plants and other creatures (as well as effects on biochemical reactions in the nature)?&#xA;Can anyone introduce a good source or explain me about that?&lt;/p&gt;&#xA;" OwnerUserId="3265" LastActivityDate="2015-07-31T13:07:51.017" Title="Day and night effects on Natural Enviroment" Tags="|human-influence|" AnswerCount="0" CommentCount="1" ClosedDate="2015-08-03T03:45:19.820" ContentLicense="CC BY-SA 3.0" />
  <row Id="5285" PostTypeId="2" ParentId="4415" CreationDate="2015-07-31T14:44:52.920" Score="-1" Body="&lt;p&gt;I believe the final ice age will happen around 100 to 150 million years from now and the sun gets 1% hotter every 100 millions years and after about 100 million years or so it will be too hot for any ice ages to happen after that point in time. &lt;/p&gt;&#xA;" OwnerUserId="3268" LastActivityDate="2015-07-31T14:44:52.920" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5286" PostTypeId="1" AcceptedAnswerId="5294" CreationDate="2015-07-31T15:14:30.907" Score="3" ViewCount="320" Body="&lt;p&gt;Suppose a giant sheet of semi-reflective mylar (or some other kind of partial sun-screening material) was temporarily placed into space between the Earth and the Sun with the intent to lower the amount of solar energy reaching the surface of the planet. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How much solar radiation (and in what frequency ranges) would need to be filtered to cool the planet to the most-desirable global temperature? Also, would the entire planet need to be shaded or just a key area like the Equatorial region? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously the plan would be to reduce the warming effect without dramatically darkening the day since so many plants require the visible spectrum of sunlight to live.&lt;/p&gt;&#xA;" OwnerUserId="3267" LastEditorUserId="3267" LastEditDate="2016-07-17T22:56:22.913" LastActivityDate="2016-07-17T22:56:22.913" Title="How much reduction of insolation (solar energy) would be required to stop global warming?" Tags="|climate-change|hypothetical|solar-terrestrial-physics|" AnswerCount="1" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5287" PostTypeId="2" ParentId="4415" CreationDate="2015-07-31T16:10:05.867" Score="1" Body="&lt;p&gt;It is very hard to exactly tell when the next ice age will happen, to tell about the last is even harder.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we support ourselves in the present state of knowledge, the Sun is in the middle of its life span, the star evolution theory (see: &lt;a href=&quot;https://en.wikipedia.org/wiki/Stellar_evolution&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Stellar_evolution&lt;/a&gt;), which means that at certain time it will start to cool down and in the next cycle it will become a giant red, increasing its volume until it engulfs Earth, destroying it.  It will grow to reach a radius in between Earth and Mars.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think that the last ice age will be very long, during the cooling and transformation in a Red start.   It will finish with the destruction of Earth by the Giant Red Sun.   It is expected to happen around 4.5 billions years from now.&lt;/p&gt;&#xA;" OwnerUserId="3269" LastActivityDate="2015-07-31T16:10:05.867" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5288" PostTypeId="1" CreationDate="2015-07-31T20:04:39.417" Score="10" ViewCount="1732" Body="&lt;p&gt;Evapotranspiration is when a plant evaporates water off the surface of its leaves in order to move water throughout its system with cohesive and adheisiveforces. My question is how will a sudden decrease in evaportranspiration in regions concentrated with agriculture affect the prevalence of rain in the region? For example, if crops died off in the agricultural region or if the water released via evapotranspiration was collecting in a greenhouse. &lt;/p&gt;&#xA;" OwnerUserId="3271" LastEditorUserId="192" LastEditDate="2015-08-05T23:00:09.273" LastActivityDate="2017-08-24T17:38:11.133" Title="How does evapotranspiration affect rainfall?" Tags="|meteorology|climate|water|rainfall|water-vapour|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5289" PostTypeId="1" AcceptedAnswerId="5295" CreationDate="2015-07-31T22:48:59.647" Score="6" ViewCount="388" Body="&lt;p&gt;Put another way, if you go back far enough in earth history, was there never a San Francisco Bay, and the mountains in the Peninsula and east of the &quot;East Bay&quot; were essentially a contiguous mass of hills?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS - I live in the Bay Area, and I know some of the features formed by the San Andreas fault.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5LiQF.png&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5LiQF.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3272" LastActivityDate="2015-08-02T02:00:01.343" Title="Is the whole San Francisco Bay Area essentially one giant fault?" Tags="|earthquakes|plate-tectonics|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5290" PostTypeId="2" ParentId="4415" CreationDate="2015-08-01T04:50:29.713" Score="4" Body="&lt;p&gt;In my opinion, there's 3 primary factors.    There's a difference between ice ages and ice age periods.  The Milankovich cycles appear to play a key role in the forming and receding of individual ice ages, but what it doesn't appear to do is trigger ice age periods.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The modern Quaternary ice age period began about 2.58 million years ago.   Milankovich cycles likely began long before then, so it's unlikely that Milankovich cycles triggered the period, only that they play a role in the cycle within the period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Same is likely true for solar maximums and minimums.  They come and go, but they aren't likely the drivers of ice age periods.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Timeline_of_glaciation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Timeline of glaciation&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;the Quaternary, the Karoo and the Andean-Saharan ice ages all happened in the last 450 million years, and they were separated by long periods so the cause should be looked at more long term.   Milankovich cycles operate on 26,000, 42,000 and 100,000 timelines, much to short to drive changes over millions of years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;OK - the 3 things.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Land and ocean placement,&#xA;Solar output (long term, not short term sunspot changes), and&#xA;CO2&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Land and Ocean Placement&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing that seems necessary for ice age periods is a large land mass over one or both of the poles.  The reason for this is pretty straight forward, land gives ice a place to grow and as land ice grows into a glacier, Albedo increases and oceans drop.   High altitude over the glacier tends to blow cold air and maintain the glacier.   Also as oceans cool, oceans can hold more CO2, dropping atmospheric CO2 and reducing the greenhouse effect.    These feedback loops tend to make ice ages colder and they are only possible with land over one or both of the poles.  Antarctica drifted over the South Pole and began forming a glacier about 30 million years ago and, in maybe 15-25 million years, it will drift off the the south pole and begin to melt.   I think, once Antarctica drifts into warmer waters, ice ages are likely to stop.   15 million years or so?   Maybe more?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's also possible that Canada or Russia drift over the North Pole and as the the giant Antarctic Glacier is replaced by a giant Arctic Glacier, but I think the general consensus is that we can expect ice ages to stop when antarctic drifts over warmer water.   We can also expect higher sea level too, lower Albedo and no more ice age cycle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Solar output&lt;/strong&gt; - long term, not short term sunspot cycles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sun growing more luminous, meaning, more energy for Earth, it's expected to grow warmer by about 10% over the next billion years - roughly 1% every 100 million years.  &lt;a href=&quot;https://en.wikipedia.org/wiki/Sun#Main_sequence&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Source)&lt;/a&gt;.  1% might not sound like much but it actually is.  Solar variation, which is believed to have caused the Mini ice age, has a variation of about 1 - 1.5 watts per square meter.   &lt;a href=&quot;http://www.skepticalscience.com/solar-activity-sunspots-global-warming-advanced.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Source)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A 1% more luminous sun would be in the range of 13-14 watts per square meter, so as the sun grows brighter, and if everything else stays the same, certainly within 100-200 million years, the sun would be sufficiently hot to make ice ages pretty darn unlikely.   This site suggests that a 10% increase in solar luminosity could result in 47 °C, 116 °F.   It will take quite a bit less than that to end ice ages.  &lt;a href=&quot;https://en.wikipedia.org/wiki/Timeline_of_the_far_future&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Source)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We also have to consider orbital drift.  If the Earth is slowly moving away from the sun, that's a factor too, and by this study, it is moving away, at 15 CM per year  &lt;a href=&quot;https://www.newscientist.com/article/dn17228-why-is-the-earth-moving-away-from-the-sun/&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Source)&lt;/a&gt;, so, in 100 million years, 150,000 km, 0.1% further from the sun, about 0.2% less solar irradiance, which is only 20% of the increase in solar output,so this, at least by current estimates, will be overshadowed by the sun growing brighter.   &lt;a href=&quot;https://www.newscientist.com/article/dn17228-why-is-the-earth-moving-away-from-the-sun/&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Source)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Carbon Sequestering / atmospheric CO2 PPM&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, and very difficult to predict over the long term is carbon sequestering.  CO2 has generally been decreasing over millions of years and the drop in CO2 may have played a role in the current ice age cycle.   It's entirely possible, though some might disagree, but it's certainly possible that our current uptick in CO2 by human activity has already knocked the next ice age off it's feet and we might have changed the planet enough to end the ice age cycle.  The orbital forcing is believed to be only about 1 degree C but ice ages can be about 10 degrees C colder due to feedback mechanisms.   Our man made increase in CO2 is expected to warm the earth more than that, so at current CO2 levels, it's entirely possible that an ice-age couldn't form.  &lt;a href=&quot;http://www.aps.org/policy/statements/07_1.cfm&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;quote:   &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The uncertainty in the estimates from various climate models for&#xA;  doubling CO2-equivalent concentration is in the range of 1°C to 3°C&#xA;  with the probability distributions having long tails out to much&#xA;  larger temperature changes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But, long term the CO2 isn't likely to stay at 400 PPM, though there's a good chance it won't drop to pre anthropomorphic levels of cycling between 180 and 280 PPM that we had during the recent ice age cycles.   That might be enough to alter the recent ice age cycle, though long term predictions about CO2 sequestering are very difficult, but I do personally believe that by burning fossil fuels, we may have actually put an end to the ice age cycle.   I'm by no means stating that as a certainty, but it's within the realm of possibility.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We've also seen CO2 levels gradually drop over millions of years, so it's possible, in a million or two years, we'll see CO2 levels even lower than we've seen and perhaps a resurgence of ice ages.   Continental drift over the next few million years is predictable and solar output over longer periods is somewhat predictable, but CO2 sequestering is enormously difficult to predict - so that's the wild card in this estimate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ywfK5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ywfK5.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As we can see from the chart, there's been a pretty steady drop in CO2 PPM over the last 15 million years or so.   As the ocean grows colder it can store more CO2 so there may be a correlation between falling temperature and falling CO2 PPM - one of the primary climate feedback mechanisms, but predicting future CO2 levels - I wouldn't even know what to guess.  Certainly low enough CO2 PPM could lead to further ice ages, even after Antarctica drifts off the south pole, so, there's the problem - too many unknowns.  This question has no answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A 4th possible key driver would be ocean currents, as indicated by the theory that the formation of the Isthmus of Panama may have been a key driver in the current ice age cycle, but predicting ocean current changes millions of years into the future is above my pay grade.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The 3 primary drivers do seem to fit past ice ages.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The the Andean-Saharan ice age period 425-450 million years ago, CO2 levels were much higher but that long ago the sun was perhaps 3%-4% less luminous and much of the land was over the antarctic circle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/m4zrF.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/m4zrF.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Karoo ice age period is associated with a drop in CO2 and an increase in O2   &lt;a href=&quot;http://gogreencanada.ucoz.com/index/ice_age_timelines/0-52&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Source)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That probably long and rambling and needs more than a little clean-up and I invite counterpoints, but I think that's the gist of estimating when ice ages will end.   A precise answer isn't possible.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2015-08-01T05:32:44.187" LastActivityDate="2015-08-01T05:32:44.187" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5291" PostTypeId="1" CreationDate="2015-08-01T05:37:14.157" Score="8" ViewCount="332" Body="&lt;p&gt;Recently, south-east Queensland has been rattled by 2 moderate earthquakes - a 5.3 a couple of days ago (&lt;a href=&quot;http://www.goldcoastbulletin.com.au/news/gold-coast/magnitude-earthquake-rocks-queensland-buildings-shaken-on-the-gold-coast/story-fnj94idh-1227462846220&quot;&gt;News report&lt;/a&gt;) and a 5.7 tremor just a few hours ago as of writing this post (&lt;a href=&quot;http://www.abc.net.au/news/2015-08-01/second-earthquake-in-two-days-felt-in-south-east-queensland/6665546&quot;&gt;News Report&lt;/a&gt;). These are significant as they are the strongest earthquakes experienced in Queensland.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The location of the earthquakes and their associated aftershocks are shown in the map from the Geoscience Australia &lt;a href=&quot;http://www.ga.gov.au/earthquakes/recentQuakes.do?when=1&amp;amp;where=2&amp;amp;which=false&amp;amp;x=46&amp;amp;y=6&quot;&gt;Earthquake map&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8ip0c.png&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8ip0c.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, I understand that these are intraplate earthquakes, but my question is,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What geological structure(s) have caused these recent earthquakes?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user2872" LastEditorDisplayName="user2872" LastEditDate="2015-08-01T06:04:10.483" LastActivityDate="2015-08-01T06:04:10.483" Title="What geological structure(s) is responsible for the recent Queensland earthquakes?" Tags="|seismology|earthquakes|intraplate|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5292" PostTypeId="2" ParentId="5282" CreationDate="2015-08-01T06:58:35.457" Score="6" Body="&lt;p&gt;Getting figures on the amount of limestone available is difficult.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apparently &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Limestone&quot;&gt;limestone&lt;/a&gt; makes up at least 10% of the total volume of all sedimentary rocks&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One way to answer your question is by inference. &lt;a href=&quot;https://en.wikipedia.org/wiki/Cement&quot;&gt;Cement&lt;/a&gt; is manufactured from limestone. Current &lt;a href=&quot;http://www.statista.com/statistics/373845/global-cement-production-forecast/&quot;&gt;global production of cement&lt;/a&gt; is in excess of 3.27 Gt/a and by 2030 it is forecast to be approximately 4.83 Gt/a. Thus if all limestone currently earmarked for cement production were diverted to neutralizing the acidity of the world's oceans it could be done at short notice. How sustainable it would be over the 200 years required, is another matter. It also raises the question of what happens to all the industries and projects that current rely on a cheap and ready supply of cement?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With much tongue in cheek, the Florida peninsular in the US is predominantly limestone, likewise a significant portion of eastern England, with the &quot;white cliffs of Dover, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Karst&quot;&gt;karst&lt;/a&gt; regions of the eastern Adriatic, southern Europe, southern and eastern Asia and the Nullabor Plain in southern Australia. Would these countries be will to sacrifice their lands to neutralize acidity in the worlds oceans?&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2015-08-01T07:14:15.733" LastActivityDate="2015-08-01T07:14:15.733" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5294" PostTypeId="2" ParentId="5286" CreationDate="2015-08-02T01:27:37.377" Score="4" Body="&lt;p&gt;It's not that hard to make an estimate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;CO2 traps about 2 watts per square meter.   Direct sunlight at 1 Astronomical Unit is about 1,360 watts per square meter, but spread out over the earth, average night and day it's about 1/4th of that about 340 watts per square meter.  (&lt;em&gt;note, Casey's point is valid, it's probably better to use the number of watts that hits the Earth, so, my estimate is likely a bit low&lt;/em&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There may be more detailed and specific ways to look at it, but this is probably pretty close.   If you shade enough sun to reduce 2 watts out of 340, or 1/170th, that should balance out climate change, at least at current levels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From space, you can view the earth as a disk in terms of area needed for shade, so the 2D area of the earth is about 127 trillion square meters, and 1/170th of that, about 750 billion square meters, or 750,000 square KM, slightly larger than Texas and as you get closer to the sun, the area needed is reduced by the square of the relative distance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Still, that's no easy task, to put up a shade the size of Texas into space and it's no easy task to keep it there as it would in effect by a huge solar sale and likely enormously heavy.   It's far easier to simply build mirrors on earth than try to build something in space and I've seen that discussed as a possible solution to climate change.   of-course, they'd need to be kept clean to be effective, it would require maintenance, but it's probably doable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source (1,360 watts):  &lt;a href=&quot;http://earthobservatory.nasa.gov/Features/EnergyBalance/page2.php&quot; rel=&quot;nofollow&quot;&gt;http://earthobservatory.nasa.gov/Features/EnergyBalance/page2.php&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;sources, 1.5-2 watts per square meter, CO2  (I went with the 2 watts estimate cause that includes CH4).   &lt;a href=&quot;http://www.easterbrook.ca/steve/2012/01/how-much-extra-energy-are-we-adding-to-the-earth-system/&quot; rel=&quot;nofollow&quot;&gt;http://www.easterbrook.ca/steve/2012/01/how-much-extra-energy-are-we-adding-to-the-earth-system/&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiative_forcing&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Radiative_forcing&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2015-08-02T02:57:24.560" LastActivityDate="2015-08-02T02:57:24.560" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="5295" PostTypeId="2" ParentId="5289" CreationDate="2015-08-02T02:00:01.343" Score="5" Body="&lt;p&gt;Much of western California is composed of small lighter landmasses scraped off of the Pacific Plate as the heavier mantle sank under the North American Plate, and the San Francisco Bay Area is no exception. Here's an illustration of how some of CA was formed as the Pacific Plate was subducted under the North American Plate:&lt;br&gt;&lt;a href=&quot;https://i.stack.imgur.com/DbGXU.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DbGXU.jpg&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As these separate landmasses were scraped off the Pacific Plate, they formed distinct rock types, with the boundary of each forming a distinct fault.  Here's a good illustration of what that looks today:&lt;br&gt;&lt;a href=&quot;https://i.stack.imgur.com/ntciq.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ntciq.jpg&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&lt;br&gt;&lt;br&gt;Of course, these faults and rock types will be different depending on what cross section you're looking at.&lt;br&gt;&lt;br&gt;I know this isn't a complete description, but I think it's a good starting point.&lt;br&gt;&lt;br&gt; These illustrations came from USGS bulletin 2195, which can be found &lt;a href=&quot;http://pubs.usgs.gov/bul/2195/b2195.pdf&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;. It's an interesting read in and of itself.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2015-08-02T02:00:01.343" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5297" PostTypeId="1" AcceptedAnswerId="5300" CreationDate="2015-08-02T17:35:51.463" Score="4" ViewCount="116" Body="&lt;p&gt;Here is a video of a waterfall lashing on to a mountain road, with vehicles driving under it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://youtu.be/cHaguj--YBc&quot; rel=&quot;nofollow&quot;&gt;https://youtu.be/cHaguj--YBc&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There appears to be a big hole carved out right next to the road, possibly by the force of the waterfall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this a ticking time bomb for a landslide?&lt;/p&gt;&#xA;" OwnerUserId="3227" LastActivityDate="2015-08-03T00:21:11.660" Title="Could a waterfall lashing onto a road lead to a landslide?" Tags="|mountains|rainfall|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5298" PostTypeId="1" CreationDate="2015-08-02T21:01:44.010" Score="9" ViewCount="141" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LK7lk.jpg&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LK7lk.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I thought it may be mammatus, but the absence of the hanging down &quot;udders&quot; made me doubt. &lt;/p&gt;&#xA;" OwnerUserId="3278" LastEditorUserId="2536" LastEditDate="2015-08-02T21:34:09.580" LastActivityDate="2015-09-26T13:40:53.560" Title="What cloud formation is this?" Tags="|clouds|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5299" PostTypeId="1" AcceptedAnswerId="5303" CreationDate="2015-08-03T00:11:47.283" Score="10" ViewCount="771" Body="&lt;p&gt;Does anybody have an explanation for the growing ring/growing circular echo that I occasionally see on weather radar? Attached is a gif of a NEXRAD loop showing areas around Denver, CO, Aug. 2, 2015 3:46 PM to 4:32 PM local time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nxTBj.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nxTBj.gif&quot; alt=&quot;NEXRAD loop around Denver, CO, Aug. 2, 2015 3:46 PM to 4:32 PM local time&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3280" LastEditorUserId="3280" LastEditDate="2015-08-06T06:22:21.377" LastActivityDate="2015-08-06T13:21:43.397" Title="Explanation for growing circular echo on weather radar?" Tags="|meteorology|storms|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5300" PostTypeId="2" ParentId="5297" CreationDate="2015-08-03T00:21:11.660" Score="3" Body="&lt;p&gt;Potentially, a landslide could occur. Whether it would be a minor slip or a major fall depends on the geological conditions at the site, the force of the water and the duration that the site is impacted by the water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the video in question, the rock face above the road appears competent, but there are not guarantees. The main issue would be is the water undermining the road which could cause a slip and the road to slide.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The more loose the geological material is, the easier it is to dislodge it. Once one item moves a chain of events can occur where additional items are dislodged and a slide occurs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to high pressure water dislodging material, water acts as a lubricant, making it easier for rocks and regolith to be dislodged.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To minimise the potential for a slide to occur in such a situation, the surface of the road would need to be sealed very well and a very good drainage system installed that would move the water away from the road and the slope below the road&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-08-03T00:21:11.660" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5301" PostTypeId="1" CreationDate="2015-08-03T01:40:29.503" Score="6" ViewCount="4211" Body="&lt;p&gt;I'm trying to find equations that would help me determine the amount of solar radiation hitting a certain latitude on a certain planet given the following inputs:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the degrees of latitude of the location in question&lt;/li&gt;&#xA;&lt;li&gt;this hemisphere's current season (winter or summer)&lt;/li&gt;&#xA;&lt;li&gt;size of the planet&lt;/li&gt;&#xA;&lt;li&gt;luminosity of the star(s) the planet orbits&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Without taking into consideration wind, air pressure, or any atmospheric effects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ideally I would like to determine the average solar radiation of a given location in both the winter and summer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My end goal is to determine the average surface temperature of a given latitude on a planet using the base solar radiation and the effects of wind, air pressure, and surface ocean currents.&lt;/p&gt;&#xA;" OwnerUserId="3049" LastActivityDate="2024-01-30T19:11:41.690" Title="Equation for solar radiation at a given latitude?" Tags="|atmosphere|atmospheric-radiation|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5302" PostTypeId="1" CreationDate="2015-08-03T03:37:43.713" Score="5" ViewCount="283" Body="&lt;p&gt;I have what i think is a piece of siltstone with an interesting pattern on the face. It looks like a lichen or lightning bolt, as shown in the picture. The interior of the pattern is the same color as the stone itself, while the negative area is black. I was wondering what may have caused this pattern to form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xnl3E.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xnl3E.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3281" LastActivityDate="2015-08-04T13:13:01.133" Title="What could have formed the pattern inside this piece of siltstone?" Tags="|geology|rocks|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5303" PostTypeId="2" ParentId="5299" CreationDate="2015-08-03T04:15:45.973" Score="11" Body="&lt;p&gt;You are seeing the gust fronts or &lt;a href=&quot;https://en.wikipedia.org/wiki/Outflow_boundary&quot; rel=&quot;nofollow&quot;&gt;outflow boundaries&lt;/a&gt; of the thunderstorms around Denver.  The rainfall from the storm provides an evaporative flux that cools the air it falls into (preserving $\theta_e$ of air descending from aloft).  This cool air is more dense than the surrounding air at and near the surface and spreads out as a density current.  The cooler the air (relative to ambient air) the faster it will spread out.  You experience the passage of the boundary as the gusty wind conditions that often precede a storm.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The movement of this density current causes the warmer air it displaces to rise (which can initiate further convection) and this concentrates and lofts insects, which is what you are seeing on radar.  In radar nomenclature you will hear these features referred to as &quot;fine lines&quot;.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2015-08-06T13:21:43.397" LastActivityDate="2015-08-06T13:21:43.397" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5304" PostTypeId="1" AcceptedAnswerId="5309" CreationDate="2015-08-03T08:32:13.540" Score="11" ViewCount="244" Body="&lt;p&gt;Okay, so I believe that most of the impact/collisions happen at oblique angles to the planet's radial direction. (I am not very sure about this, but since it is not a freefall, we can assume that the collision is oblique).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So why are most of the craters radially symmetric? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why isn't the depression skewed?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have almost never come across a photograph of a skewed crater.&lt;/p&gt;&#xA;" OwnerUserId="3164" LastActivityDate="2015-08-04T06:17:48.013" Title="Why are impact craters radially symmetric?" Tags="|planetary-science|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5306" PostTypeId="1" AcceptedAnswerId="5307" CreationDate="2015-08-03T20:07:49.033" Score="0" ViewCount="542" Body="&lt;p&gt;Can some of the gaseous chemicals in many of the car exhaust by-products of the combustion engine be carcinogenic or cancer-causing?. Could car exhaust behave in a ways that are similar to 'second' hand smoke' from cigarettes that is known to cause many health problems? Can such pollution always be cleaned up or at least 'filtered out'? &lt;/p&gt;&#xA;" OwnerUserId="1371" LastEditorUserId="1371" LastEditDate="2015-09-29T21:38:21.053" LastActivityDate="2015-09-29T21:38:21.053" Title="Regarding car exhaust and its possible carcinogenic effects" Tags="|pollution|environmental-protection|" AnswerCount="1" CommentCount="12" ClosedDate="2015-08-03T23:56:53.163" ContentLicense="CC BY-SA 3.0" />
  <row Id="5307" PostTypeId="2" ParentId="5306" CreationDate="2015-08-03T23:04:25.220" Score="3" Body="&lt;p&gt;Yes almost definitely. Its not just gas, but additives, lubricants/oils, coatings, coolant (some of which leaks into the combustion chamber) etc. The full list of known carcinogens is available &lt;a href=&quot;http://www.cancer.org/cancer/cancercauses/othercarcinogens/generalinformationaboutcarcinogens/known-and-probable-human-carcinogens&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also see the EPA report &lt;a href=&quot;http://www.epa.gov/otaq/consumer/02-toxic.pdf&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt; which says ... &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;EPA estimates that mobile (car, truck, and bus) sources of air toxics account for as much as half of all cancers attributed to outdoor sources of air toxics. This estimate is not based on actual cancer cases, but on models that predict the maximum number of cancers that could be expected from current levels of&#xA;exposure to mobile source emissions.&quot;&lt;/p&gt;&#xA;" OwnerUserId="1275" LastActivityDate="2015-08-03T23:04:25.220" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5308" PostTypeId="2" ParentId="5304" CreationDate="2015-08-04T05:09:42.167" Score="7" Body="&lt;p&gt;The main reason why impact craters are close to symmetrically round is because it's the explosion of the impactor, not its collision, that creates the impact crater. The impactor is travelling so fast that, rather than simply exploding on impact, it burrows deep into the collision site, heats up from compression and friction, and explodes deep underground, thus creating a more-or-less perfectly round crater.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2015-08-04T05:09:42.167" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5309" PostTypeId="2" ParentId="5304" CreationDate="2015-08-04T06:17:48.013" Score="6" Body="&lt;p&gt;A quick search reveals the &lt;a href=&quot;https://en.wikipedia.org/wiki/Impact_crater&quot;&gt;answer&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Impact cratering involves high velocity collisions between solid objects, typically much greater than the velocity of sound in those objects. Such hyper-velocity impacts produce physical effects such as melting and vaporization that do not occur in familiar sub-sonic collisions.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Impacts at these high speeds produce shock waves in solid materials, and &lt;strong&gt;both impactor and the material impacted are rapidly compressed to high density&lt;/strong&gt;. &lt;strong&gt;Following initial compression, the high-density, over-compressed region rapidly depressurizes, exploding violently, to set in train the sequence of events that produces the impact crater&lt;/strong&gt;. Impact-crater formation is therefore more closely analogous to cratering by high explosives than by mechanical displacement. Indeed, the energy density of some material involved in the formation of impact craters is many times higher than that generated by high explosives. &lt;strong&gt;Since craters are caused by explosions, they are nearly always circular&lt;/strong&gt; – only very low-angle impacts cause significantly elliptical craters.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-08-04T06:17:48.013" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5311" PostTypeId="2" ParentId="5247" CreationDate="2015-08-04T12:56:34.477" Score="5" Body="&lt;p&gt;&lt;a href=&quot;http://peter.zahuczki.hu/index.php/myapps/clp&quot;&gt;Here is a link to a colored inversion operator design code written and provided by Peter Zahuczki.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This code requires that you provide a P-impedance log amplitude spectrum; he uses the open-source interpretation software &lt;a href=&quot;http://opendtect.org/&quot;&gt;OpendTect&lt;/a&gt; to compute this spectrum.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Peter has a easy to follow tutorial on how to use his code with OpendTect. Good luck!&lt;/p&gt;&#xA;" OwnerUserId="3256" LastActivityDate="2015-08-04T12:56:34.477" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5312" PostTypeId="2" ParentId="5302" CreationDate="2015-08-04T13:05:58.987" Score="1" Body="&lt;p&gt;Interesting. The photo is low quality so I can not say for sure but possible candidate explanations are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;a septarian concretion&lt;/li&gt;&#xA;&lt;li&gt;a fulgorite&lt;/li&gt;&#xA;&lt;li&gt;a dendrite&lt;/li&gt;&#xA;&lt;li&gt;a differential staining based on differences in porosity&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;To get a better answer please include some close-ups of the central area and some pictures of the other sides of the rock&lt;/p&gt;&#xA;" OwnerUserId="585" LastEditorUserId="585" LastEditDate="2015-08-04T13:13:01.133" LastActivityDate="2015-08-04T13:13:01.133" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5313" PostTypeId="1" CreationDate="2015-08-04T14:19:09.210" Score="12" ViewCount="7027" Body="&lt;p&gt;In a thunderstorm cloud about sunset time, I saw these clouds, including some (in the upper right) that were a unique shade of blue.  I don't think I've seen clouds quite that color before.  I tried to capture the color as best I could with a digital camera, though the blue is slightly washed out in the image.  I took these images facing East at sunset time, during summer. There were rivers (that you could probably throw a rock over if you had a good arm) in the general vicinity, but no large bodies of water such as lakes or oceans.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/dGsHk.jpg&quot; alt=&quot;photo of clouds with blue in upper right&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;Optically zooming in on the blue cloud:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/25gBn.jpg&quot; alt=&quot;Zooming in on the blue cloud&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://physics.stackexchange.com/a/82818/87049&quot;&gt;This answer&lt;/a&gt; suggests that the sunlight should be missing those wavelengths (&amp;quot;at sunset, when only the red/yellow end of the spectrum hits&amp;quot;) which is consistent with the brilliant warm colors to the left.  But...the cloud was a strong and unique shade of blue, different from the blue behind it.  How does this happen?  That is, what natural processes underly the occurrence?&lt;/p&gt;&#xA;&lt;p&gt;(Although &lt;a href=&quot;https://physics.stackexchange.com/questions/81464/why-do-clouds-appear-black&quot;&gt;that question&lt;/a&gt; is on &lt;a href=&quot;https://physics.stackexchange.com/&quot;&gt;Physics.SE&lt;/a&gt;, there seem to be more &lt;a href=&quot;https://earthscience.stackexchange.com/questions/5068/why-do-clouds-have-areas-of-darkness-instead-of-scattering-light-to-produce-a-ra&quot;&gt;questions&lt;/a&gt; &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4452/what-causes-these-banded-clouds&quot;&gt;about&lt;/a&gt; &lt;a href=&quot;https://earthscience.stackexchange.com/questions/5044/why-are-clouds-darker-before-it-rains&quot;&gt;cloud&lt;/a&gt; &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2264/where-can-we-see-the-noctilucent-clouds&quot;&gt;appearances&lt;/a&gt; on this site.)&lt;/p&gt;&#xA;" OwnerUserId="3244" LastEditorUserId="3244" LastEditDate="2023-07-24T15:27:32.900" LastActivityDate="2023-07-24T15:27:32.900" Title="What causes clouds to appear blue?" Tags="|meteorology|atmosphere|clouds|" AnswerCount="4" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="5315" PostTypeId="2" ParentId="5204" CreationDate="2015-08-05T01:02:03.027" Score="1" Body="&lt;p&gt;During the Maunder Minimimum, a famous mini ice age in the middle ages, atmospheric CO2 was less than 300 ppm.  Last year it pushed above 400 ppm.  Solar variations will not make any difference to the long term warming trend.&lt;/p&gt;&#xA;" OwnerUserId="3288" LastActivityDate="2015-08-05T01:02:03.027" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5316" PostTypeId="1" AcceptedAnswerId="5317" CreationDate="2015-08-05T01:10:46.357" Score="15" ViewCount="1196" Body="&lt;p&gt;The IPCC 2013 Physical Science Basis Report says 0.4m - 0.6m.  That is somewhat dated and now &lt;a href=&quot;http://www.atmos-chem-phys-discuss.net/15/20059/2015/acpd-15-20059-2015.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.atmos-chem-phys-discuss.net/15/20059/2015/acpd-15-20059-2015.html&lt;/a&gt; seem to have contested it.  Is it safe for local governments to plan on the basis of 0.4 - 0.6 meters, or is there another value that would be better?&lt;/p&gt;&#xA;&lt;p&gt;Their abstract is summarized below for reference.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;There is evidence of ice melt, sea level rise to +5–9 m, and extreme storms in the prior interglacial period that was less than 1 °C warmer than today. Human-made climate forcing is stronger and more rapid than paleo forcings, but much can be learned by combining insights from paleoclimate, climate modeling, and on-going observations. We argue that ice sheets in contact with the ocean are vulnerable to non-linear disintegration in response to ocean warming, and we posit that ice sheet mass loss can be approximated by a doubling time up to sea level rise of at least several meters. Doubling times of 10, 20 or 40 years yield sea level rise of several meters in 50, 100 or 200 years. Paleoclimate data reveal that subsurface ocean warming causes ice shelf melt and ice sheet discharge. Our climate model exposes amplifying feedbacks in the Southern Ocean that slow Antarctic bottom water formation and increase ocean temperature near ice shelf grounding lines, while cooling the surface ocean and increasing sea ice cover and water column stability. Ocean surface cooling, in the North Atlantic as well as the Southern Ocean, increases tropospheric horizontal temperature gradients, eddy kinetic energy and baroclinicity, which drive more powerful storms. We focus attention on the Southern Ocean's role in affecting atmospheric CO2 amount, which in turn is a tight control knob on global climate. The millennial (500–2000 year) time scale of deep ocean ventilation affects the time scale for natural CO2 change, thus the time scale for paleo global climate, ice sheet and sea level changes. This millennial carbon cycle time scale should not be misinterpreted as the ice sheet time scale for response to a rapid human-made climate forcing. Recent ice sheet melt rates have a doubling time near the lower end of the 10–40 year range. We conclude that 2 °C global warming above the preindustrial level, which would spur more ice shelf melt, is highly dangerous. Earth's energy imbalance, which must be eliminated to stabilize climate, provides a crucial metric.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="3288" LastEditorUserId="543" LastEditDate="2021-06-21T06:45:25.693" LastActivityDate="2021-06-21T06:45:25.693" Title="What is a reasonable forecast of sea level in 2100?" Tags="|climate-change|sea-level|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="5317" PostTypeId="2" ParentId="5316" CreationDate="2015-08-05T03:01:29.157" Score="11" Body="&lt;p&gt;An important aspect of this is location.  Sea-level rise will not be exactly uniform across the globe and tides/storms will cause a lot of regional variability in terms of coastal change.   Local governments should not necessarily be planning for an average global sea-level rise but instead develop a regional understanding of the coastal effects they will likely experience.  For instance, see California's recent CALIFORNIA COASTAL COMMISSION&#xA;SEA LEVEL RISE POLICY GUIDANCE here:  &lt;a href=&quot;http://documents.coastal.ca.gov/assets/slr/guidance/July2015_Full_RecFinal.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://documents.coastal.ca.gov/assets/slr/guidance/July2015_Full_RecFinal.pdf&lt;/a&gt;&#xA;which says&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Sea level at the San Francisco tide gauge has risen 8 in (20 cm) over the past&#xA;century, and the National Research Council (NRC) projects that by Year 2100, sea level in&#xA;California may rise by 4 to 56 in (10 to 143 cm) for areas north of Cape Mendocino and 17 to 66&#xA;in (42 to 167 cm) for areas south of Cape Mendocino (NRC 2012). While the California coast&#xA;regularly experiences erosion, flooding, and significant storm events, sea level rise will&#xA;exacerbate these natural forces, leading to significant social, environmental, and economic&#xA;impacts.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The estimate of 0.6 meters has increased as recent research shows Greenland's melt rate is a bit faster than previously estimated and ocean warming, which causes expansion, is also happening more rapidly.&lt;/p&gt;&#xA;&lt;p&gt;Below  is some useful information from the 2014 US National Climate Assessment ( &lt;a href=&quot;http://nca2014.globalchange.gov/report/our-changing-climate/sea-level-rise&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://nca2014.globalchange.gov/report/our-changing-climate/sea-level-rise&lt;/a&gt; ).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Global sea level has risen by about 8 inches since reliable record keeping began in 1880. It is projected to rise another 1 to 4 feet by 2100.&lt;/p&gt;&#xA;&lt;p&gt;Projecting future rates of sea level rise is challenging. Even the most sophisticated climate models, which explicitly represent Earth’s physical processes, cannot simulate rapid changes in ice sheet dynamics, and thus are likely to underestimate future sea level rise. In recent years, “semi-empirical” methods have been developed to project future rates of sea level rise based on a simple statistical relationship between past rates of globally averaged temperature change and sea level rise. These models suggest a range of additional sea level rise from about 2 feet to as much as 6 feet by 2100, depending on emissions scenario.&lt;/p&gt;&#xA;&lt;p&gt;Recent projections show that for even the lowest emissions scenarios, thermal expansion of ocean waters and the melting of small mountain glaciers will result in 11 inches of sea level rise by 2100, even without any contribution from the ice sheets in Greenland and Antarctica. This suggests that about 1 foot of global sea level rise by 2100 is probably a realistic low end. On the high end, recent work suggests that 4 feet is plausible.,,,, In the context of risk-based analysis, some decision makers may wish to use a wider range of scenarios, from 8 inches to 6.6 feet by 2100., In particular, the high end of these scenarios may be useful for decision makers with a low tolerance for risk&lt;/p&gt;&#xA;&lt;p&gt;In the next several decades, storm surges and high tides could combine with sea level rise and land subsidence to further increase flooding in many of these regions. Sea level rise will not stop in 2100 because the oceans take a very long time to respond to warmer conditions at the Earth’s surface. Ocean waters will therefore continue to warm and sea level will continue to rise for many centuries at rates equal to or higher than that of the current century&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The discussion paper, which is still undergoing peer-review at the time of this post, brings into question the semi-empirical methods used to calculate the rate of sea-level rise on the decade-scale.  As an alternative, they use paleo-climate data and doubling times to make their own approximation, which predicts faster sea level rise.  Let us be clear, though, the amount of possible net sea level rise over the next few hundred years or so is not really in question. The timing of how fast the sea will rise over the coming century is what is less certain.  So, a coastal community doing long term planning could consider sea-level rise even further in the future.  Most of Greenland could melt over the next few hundred years, which would contribute nearly 6 meters of sea level rise. If we are strictly talking about the year 2100, though, that is a difficult forecast to make. For planning purposes, it would be wise to assume at least 1 meter of sea level rise by 2100, with definite continued increases.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-08-14T00:24:34.897" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5318" PostTypeId="1" CreationDate="2015-08-05T09:54:05.447" Score="12" ViewCount="160" Body="&lt;p&gt;I have seen gap flows mentioned in the literature, for example [Gohm et al. 2004, Zängl 2002, Mayr et al. 2007].  Whiteman 2000 defines a gap as a &quot;major erosional opening through mountain ranges&quot; and states that a channel can occur &quot;between mountain ranges&quot;.  He goes on to discuss pressure-driven channelling and forced channelling.  I assume that such flows can occur through an gap but might be more obvious (and more easily observed) in elongated channels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone help clarify the distinctions between gaps, channels, passes and valleys and if there are distinctions between the flows associated with these types of terrain.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;References&lt;/h2&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Gohm, A., Zängl, G., &amp;amp; Mayr, G. J. (2004). South foehn in the Wipp Valley on 24 October 1999 (MAP IOP 10): Verification of high-resolution numerical simulations with observations. Monthly weather review, 132, 78-102.&lt;/li&gt;&#xA;&lt;li&gt;Mayr, G. J., Armi, L., Gohm, A., Zängl, G., Durran, D. R., Flamant, C., ... &amp;amp; Weissmann, M. (2007). Gap flows: results from the Mesoscale Alpine Programme. Quarterly Journal of the Royal Meteorological Society, 133, 881-896.&lt;/li&gt;&#xA;&lt;li&gt;Whiteman, C. D. (2000). Mountain meteorology: fundamentals and applications. Oxford University Press.&lt;/li&gt;&#xA;&lt;li&gt;Zängl, G. (2002). Stratified flow over a mountain with a gap: Linear theory and numerical simulations. Quarterly Journal of the Royal Meteorological Society, 128, 927-949.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="183" LastEditorUserId="183" LastEditDate="2015-08-05T11:05:02.430" LastActivityDate="2015-08-05T11:05:02.430" Title="Is there a distinction between gap winds and channelled flow?" Tags="|meteorology|mountains|dynamics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5319" PostTypeId="1" CreationDate="2015-08-05T16:36:35.223" Score="6" ViewCount="1418" Body="&lt;p&gt;Earth has three convection cells per hemisphere. These are the Polar cell, Ferrel cell and Hadley cell. These create the trade winds, westerlies and polar easterlies which control many aspects of climate, such as where rain shadows &amp;amp; dry zones are located and where ocean currents flow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Zbz0g.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Zbz0g.png&quot; alt=&quot;Diagram of Earth&amp;#39;s atmospheric circulation patterns&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, if you were to slow down the rotation rate of a planet, you could turn those three convection cells into a single, gigantic convection cell. Assume a roughly Earth-like planet in all characteristics (sans rotation rate, which is slowed down in order to turn the three convection cells into one - and apparently axial tilt might have an effect, I'm not sure). &lt;strong&gt;Because climate is a combination of multiple factors, there are several questions to consider:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;How would the movement of oceanic currents be affected?&lt;/li&gt;&#xA;&lt;li&gt;In what direction would the wind blow at different latitudes of the planet's surface?&lt;/li&gt;&#xA;&lt;li&gt;Where would the dry zones of the planet be? The wet zones?&lt;/li&gt;&#xA;&lt;li&gt;Where would the hot zones of the planet be? The cold zones?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Bonus:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;How would this affect violent weather phenomena such as hurricanes and tornadoes?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="3291" LastEditorUserId="725" LastEditDate="2015-10-24T00:35:09.073" LastActivityDate="2015-10-24T00:35:09.073" Title="What would the climate be like on an Earth-like planet if it had only one convection cell per hemisphere?" Tags="|atmosphere|climate|ocean-currents|hypothetical|convection|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5320" PostTypeId="2" ParentId="5288" CreationDate="2015-08-05T20:50:36.737" Score="7" Body="&lt;p&gt;Without water in the air, clouds cannot form and evaporate quickly if they do and so a sudden drop in evapotranspiration that resulted in low humidity could decrease the prevalence of rain. But, in simulations, there's not usually much of a measurable effect (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/0273117787902900?np=y&quot; rel=&quot;noreferrer&quot;&gt;http://www.sciencedirect.com/science/article/pii/0273117787902900?np=y&lt;/a&gt;). This is because there's a lot more going into this than just evaporation from plants and the total amount of water that winds up in the region's atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Air is constantly moving and there's a lot of it, and so to have a measurable impact, this would need to be a pretty large region and/or evapotranspiration would need to stop for an extended period of time.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Plants have a greater impact on their environment than what can be measured through evapotranspiration&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Evapotranspiration affects energy balance, which means that sunlight also plays a role in the ultimate effects. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The result is a rather complex web of interactions and an effect that would be very different depending on season, region, and how the loss of evapotranspiration occurred. So, the two scenarios you proposed would have very different effects.&lt;/p&gt;&#xA;" OwnerUserId="2871" LastActivityDate="2015-08-05T20:50:36.737" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5321" PostTypeId="1" AcceptedAnswerId="8979" CreationDate="2015-08-05T16:16:29.363" Score="11" ViewCount="42826" Body="&lt;p&gt;I'm living near a sea, and it rains mostly and heavily at night from 11 PM to 3 AM. The weather is mostly clear during daytime.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Air is generally cooler at night, and cool air holds less moisture than warm air resulting in rainfall.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There is a similar Phys.SE question &lt;a href=&quot;https://physics.stackexchange.com/q/139164/&quot;&gt;here&lt;/a&gt; which states the same thing. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this the only reason why it rains most at night, or are there any other factors which may affect the reason for raining more at night?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: I live in Chennai, India. &lt;/p&gt;&#xA;" OwnerUserId="3290" OwnerDisplayName="Madhan" LastEditorUserId="-1" LastEditDate="2017-04-13T12:40:15.470" LastActivityDate="2021-07-26T13:57:32.977" Title="Why does it rain more at night than during the day?" Tags="|meteorology|precipitation|thermodynamics|coastal|diurnal-cycle|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="5322" PostTypeId="2" ParentId="5301" CreationDate="2015-08-05T22:07:15.937" Score="11" Body="&lt;p&gt;Ignoring meteorological factors and any dust or satellites, this is still an incomplete problem. You would also need to know the rotation axis. For example, Uranus rotates completely on its side (i.e. it rotates at 97.77 degrees, while earth rotates at 23 degrees, 26 minutes and 21.4119 seconds). Such things become important for factors like the Arctic Circle. You are also missing the distance between the planet and the star. That becomes important when you consider that Pluto is colder than Mercury. This is needed for the formulation of the sterdian.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In your question, you said to ignore atmospheric effects. However, the atmosphere also acts as a secondary source of radiation (the infamous greenhouse effect). Even if you neglect eddies, advection, etc. you also need to consider that the atmosphere can absorb radiation and emit it back to the surface, otherwise you would find the average temperature of the surface to be the same as the average temperature of the earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: I found a decent approximation (approximation being the key word).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let $Q_S$ is the incoming solar radiation flux&#xA;$$Q_s= S(1-\alpha)(\frac{\bar{d}}{d})^2cos(\zeta)\tau_s $$&#xA;Where $S$ is the solar constant, $\alpha$ is the albedo, $d$ is the distance of the earth from the sun, $\bar{d}$ is the mean distance of the earth from the sun and $\tau_s$ is the transmissivity of the atmosphere (including any clouds above).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The last factor, $cos(\zeta)$ can be computed by$$cos(\zeta)=sin(\psi)sin(\delta)+cos(\psi)cos(\delta)cos(h)$$ where $$\delta=23.45\times\frac{\pi}{180}cos(\frac{2\pi\times(d-d_{solst})}{d_{year}})$$&#xA;Where $d$ is the Julian day, $d_{solst}$ is the julian day of the solstice (173) and $d_{year}$ is the number of days in the year (365.25)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, $h$ is the local hour, as defined by $$h=\frac{(t_{UTC}-12)\times\pi}{12}+\frac{\lambda\pi}{180}$$ where $\lambda$ is the longitude and $t_{UTC}$ is the time in UTC (in hours).&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2016-10-17T15:09:19.273" LastActivityDate="2016-10-17T15:09:19.273" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5323" PostTypeId="2" ParentId="5172" CreationDate="2015-08-05T22:48:21.143" Score="1" Body="&lt;p&gt;The answer before me is correct, but that is not the only reason why digital filters are used. After the data assimilation procedure occurs, the resulting model state may not be in equilibrium. For example, if geopotential height (or surface pressure) is updated in the assimilation procedure, but wind is not (or vice versa), then the assimilated fields are out of quasi-geostrophic balance. This can also be applied to the hydrostatic approximation. Being that the resultant fields are out of balance, gravity waves may occur in the model, but may not actually occur physically. The digital filter reduces most of these gravity waves. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have a Met Ed account, this will help explain &lt;a href=&quot;http://www.meted.ucar.edu/nwp/pcu1/d_adjust/6_0.htm&quot; rel=&quot;nofollow&quot;&gt;http://www.meted.ucar.edu/nwp/pcu1/d_adjust/6_0.htm&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2015-08-05T22:48:21.143" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5324" PostTypeId="1" CreationDate="2015-08-06T13:50:53.470" Score="6" ViewCount="774" Body="&lt;p&gt;I am at a farm where previous tenants left a non-biodegradable plastic film roughly 10-15 years ago.  It is inconsistently spread over a few acres and was not discovered until we attempted plowing the fields.  The fields are overgrown with weeds (grasses, thistles, small shrubs, etc.) about 1m tall and this growth has fragmented the plastic considerably (see image, left).&#xA;The plastic must be removed in order for food to be safely grown there, and to meet the organic standards of the farm.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What method and equipment (such as an excavator) would best remove the plastic and top layers of soil, with minimal damage to the remaining soil (ie minimal degradation)?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/cUiam.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cUiam.jpg&quot; alt=&quot;close-up of black plastic,left, and view of field growth, right.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3295" LastEditorUserId="2470" LastEditDate="2015-08-06T14:51:34.213" LastActivityDate="2015-08-06T14:51:34.213" Title="Removing agricultural plastic film waste after 10+ years degradation" Tags="|soil|environmental-protection|agriculture|" AnswerCount="1" CommentCount="3" ClosedDate="2015-08-07T14:43:47.877" ContentLicense="CC BY-SA 3.0" />
  <row Id="5325" PostTypeId="2" ParentId="5324" CreationDate="2015-08-06T14:48:10.880" Score="4" Body="&lt;p&gt;One issue that you've got is the area will be contaminated with fragments of plastic that are microscopic in size to large pieces and they will be at varying depths throughout the soil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To most people that wouldn't be much of a problem, but for you, who wants to grow food with an organic certification it's going to be a major problem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Setting fire to that land and burning the plastic with dried vegetation is not a option for you and your desired organic accreditation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you can't use the land for another purpose, such a site for new buildings, a parking lot for visitors, or a new roadway you may need to dig deeply to remove the affected soil, and more, and then import replacement soil from elsewhere.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-08-06T14:48:10.880" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5326" PostTypeId="1" AcceptedAnswerId="5327" CreationDate="2015-08-07T11:58:55.860" Score="1" ViewCount="2156" Body="&lt;p&gt;What is the causal link behind the correlation of melanoma: negatively with UV index, negatively with ozone in the lower atmosphere, and positively with ozone in the upper atmosphere? Intuitively, melanoma would positively correlate with UV index, and negatively with upper atmospheric ozone. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Increased melanoma risk with higher latitude seems to be true on a global scale as well as locally in the US, but is reversed locally in the UK and Australia where melanoma rate negatively correlates with latitude. &lt;strong&gt;Could high population density and high ozone in the lower atmosphere be affecting a lower risk of melanoma?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;It appears melanoma rates do not always negatively correlate with ozone in the upper atmosphere, and positively with high UV index.&lt;/li&gt;&#xA;&lt;li&gt;It does appear that melanoma sometimes negatively correlates with population density and ozone in the lower atmosphere (caused by pollution in heavily populated areas).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In &lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2923966/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this study&lt;/a&gt;, Chinese individuals living in the US have a higher risk of melanoma than those in China. The map of the United States with the highest rates of skin cancer (below in blue) appears to strongly correlate with a map of ozone in the lower atmosphere (below in orange).&#xA;&lt;a href=&quot;https://i.stack.imgur.com/SUQ3R.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SUQ3R.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Positively correlating latitude with rate of melanoma (higher towards the poles)&lt;/h2&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;US &lt;a href=&quot;http://www.cdc.gov/cancer/skin/statistics/state.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;map&lt;/a&gt; from CDC in cases per 100,000&#xA;&lt;a href=&quot;https://i.stack.imgur.com/vCX5X.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vCX5X.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;World &lt;a href=&quot;http://www.nature.com/nature/journal/v515/n7527_supp/images_article/515S110a-g3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;map&lt;/a&gt; from Nature&#xA;&lt;a href=&quot;https://i.stack.imgur.com/mJonK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mJonK.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h2&gt;Negatively correlating latitude and population density with rate of melanoma&lt;/h2&gt;&#xA;&#xA;&lt;h2&gt;UK&lt;/h2&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;UK melanoma rate &lt;a href=&quot;http://www.bbc.com/news/health-27141760&quot; rel=&quot;nofollow noreferrer&quot;&gt;map&lt;/a&gt; from BBC&#xA;&lt;a href=&quot;https://i.stack.imgur.com/0w4nN.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0w4nN.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;UK population density map. Population density seems to negatively correlate with melanoma.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/EP6yD.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EP6yD.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h2&gt;Australia&lt;/h2&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Australia melanoma &lt;a href=&quot;http://www.cancer.org.au/preventing-cancer/sun-protection/vitamin-d/how-much-sun-is-enough.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;guidelines&lt;/a&gt; from Cancer.org.au stating the north has a higher risk for melanoma. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/t2FVh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/t2FVh.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Australia population density map. Population density seems to negatively correlate with melanoma.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/pl8ke.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pl8ke.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h2&gt;Negatively correlating latitude with UV index (higher towards the equator)&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Nodho.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Nodho.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Crt5C.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Crt5C.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Positively correlating temperate zones with ozone in the upper atmosphere.&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tJ0Xa.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tJ0Xa.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/d8dpr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/d8dpr.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3296" LastEditorUserId="3296" LastEditDate="2015-08-07T23:17:50.987" LastActivityDate="2015-08-07T23:17:50.987" Title="Why do maps of melanoma prevalence correlate negatively with UV index, negatively with ground ozone, and positively with atmospheric ozone levels?" Tags="|pollution|ozone|" AnswerCount="2" CommentCount="6" ClosedDate="2015-08-28T02:14:40.190" ContentLicense="CC BY-SA 3.0" />
  <row Id="5327" PostTypeId="2" ParentId="5326" CreationDate="2015-08-07T14:20:42.900" Score="3" Body="&lt;p&gt;I cannot address your specific questions, but with regards to cancer, &lt;a href=&quot;http://www.ucsd.edu/directory/search?entry=Cedric%20Garland&quot; rel=&quot;nofollow&quot;&gt;Cedric Garland&lt;/a&gt; has analyzed and presented similar data and attributed a lower incidence of cancer with a higher production of vitamin D at the lower latitudes as a possible reason. &lt;a href=&quot;http://www2.lbl.gov/LBL-Programs/lifesciences/BissellLab/minapersonal/minacv2.htm&quot; rel=&quot;nofollow&quot;&gt;Mina Bissel&lt;/a&gt; at Berkeley labs and others have discovered that cells in isolation can lead to cancer. The other connecting link is that vitamin D promotes intercellular communications and thus may be aiding whatever process it is that leads to cancer. If you just google these names, vitamin D and cancer, you will find links to most if not all the papers.&lt;/p&gt;&#xA;" OwnerUserId="3298" LastActivityDate="2015-08-07T14:20:42.900" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5328" PostTypeId="1" AcceptedAnswerId="5343" CreationDate="2015-08-07T14:28:31.707" Score="5" ViewCount="1157" Body="&lt;p&gt;I live very near an extinct Andesite volcano and hiking in that area I've noticed bands of soil that have a dark red coloration. I've also been in Kauai, one of the volcanic islands of Hawaii, but those soils appear to be a lighter, almost orange color which I've heard is attributed to iron content.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So for the soil in my local neighborhood, what is the likely constituent that gives it the dark red color? Is there a simple chemical test I can use to confirm it's iron?&lt;/p&gt;&#xA;" OwnerUserId="3298" LastActivityDate="2015-08-09T12:29:08.307" Title="Red volcanic soils - what are the likely constituents?" Tags="|volcanology|soil|iron|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5329" PostTypeId="2" ParentId="5326" CreationDate="2015-08-07T16:02:56.387" Score="3" Body="&lt;p&gt;Regarding linking population density with cases of melanoma, that causal link occurs with all diseases. Cases don't occur where people don't live, they occur where people do live. Consequently, the likelihood of cases occurring increases with population density.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;UV C radiation is blocked by nitrogen in the upper atmosphere. Upper atmospheric &lt;a href=&quot;https://en.wikipedia.org/wiki/Ozone_layer&quot; rel=&quot;nofollow&quot;&gt;ozone&lt;/a&gt; acts as a barrier to UV radiation by absorbing most of the UV B radiation and whereas UV A radiation is not blocked by the atmosphere. Near surface ozone will not do anything to protect against UV radiation. &lt;a href=&quot;https://en.wikipedia.org/wiki/Ozone&quot; rel=&quot;nofollow&quot;&gt;Ozone&lt;/a&gt; is very reactive and is a powerful oxidizing agent and can damage skin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Prolonged exposure to lower levels of UV radiation (low &lt;a href=&quot;https://en.wikipedia.org/wiki/Ultraviolet_index&quot; rel=&quot;nofollow&quot;&gt;UV index&lt;/a&gt;) can be more damaging than short exposure to high UV index radiation. UV index is a poor guide to the likelihood of developing melanoma, or any other form of skin cancer. Duration of exposure is very critical.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When it's hot people to tend to stay out of the sun, which also reduces their exposure to UV radiation. When it's cooler, people tend to stay out in the sunshine, increasing their exposure to UV radiation. &lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-08-07T16:02:56.387" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5330" PostTypeId="2" ParentId="5328" CreationDate="2015-08-07T17:15:06.703" Score="2" Body="&lt;p&gt;Soil redness is typically from hematite (an iron oxide). The mixture of other minerals and organic products and how well-drained the soil is determines the exact shade. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can buy soil test kits that include iron, or, alternatively, run some distilled water through a soil sample over a cheese cloth or two and use a water test kit on the filtrate (water test kits with iron testing tend to be cheaper than soil ones - although depending on the limit of detection for the kit, you might need to use a lot of water and soil and then boil down the water to get a high enough concentration to test positive). &lt;/p&gt;&#xA;" OwnerUserId="2871" LastActivityDate="2015-08-07T17:15:06.703" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5331" PostTypeId="2" ParentId="4652" CreationDate="2015-08-07T21:10:20.630" Score="4" Body="&lt;p&gt;This has sat untouched for a while, so I did a quick search and found &lt;a href=&quot;http://scienceblogs.com/startswithabang/2013/08/08/the-top-5-things-wed-miss-if-we-didnt-have-a-moon/&quot; rel=&quot;nofollow&quot;&gt;this article&lt;/a&gt; which sums it up nicely.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They key factors with regard to earth science would be:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Less extreme tides. The tides would only be linked to the sun and would not be as strong. They would also peak at noon. This has obvious implications for any coastal processes that rely on the tides. Many industries would be impacted. For one, the Bay of Fundy wouldn't be quite the tourist attraction it is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Day length would potentially shorten at a greater rate. Our tidal lock to the moon helps to stabilize the slowing rotation of the Earth. In terms of Earth Science, this would have implications on any diurnal processes (weather), with compounding long-term effects (the climate).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) The axial tilt of the Earth would change quite a bit. The moon helps to maintain our reasonably stable tilt. Greater tilt would result in more extreme seasonal changes, which in turn would affect all sorts of processes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Those are the bigger ones from an Earth Science perspective.&lt;/p&gt;&#xA;" OwnerUserId="3258" LastActivityDate="2015-08-07T21:10:20.630" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5332" PostTypeId="1" AcceptedAnswerId="5335" CreationDate="2015-08-08T02:09:42.933" Score="17" ViewCount="13611" Body="&lt;p&gt;Eyeballing a map of the world, it seems that most mountain ranges that don't occur along continental fault lines run parallel to coastlines. Is there a reason for this?&lt;/p&gt;&#xA;" OwnerUserId="3301" LastEditorDisplayName="user12525" LastEditDate="2019-04-24T08:15:32.167" LastActivityDate="2019-04-24T08:15:32.167" Title="Is there a reason most mountain ranges seem to run parallel to coastlines?" Tags="|geology|plate-tectonics|mountains|coastal|orogeny|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5333" PostTypeId="1" AcceptedAnswerId="5334" CreationDate="2015-08-08T04:42:41.777" Score="0" ViewCount="1802" Body="&lt;p&gt;I received a project which there's the follow topic:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Waste Water Reclamation and Reuse&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Are they not the same meaning, reuse and &lt;a href=&quot;http://www.ecologydictionary.org/wastewater_reclamation&quot; rel=&quot;nofollow noreferrer&quot;&gt;reclamation&lt;/a&gt; in this case?&lt;/p&gt;&#xA;" OwnerUserId="3302" LastEditorUserId="3302" LastEditorDisplayName="user2872" LastEditDate="2020-10-20T17:33:05.110" LastActivityDate="2020-10-20T17:33:05.110" Title="What's the difference between Waste Water Reclamation and Waste Water Reuse?" Tags="|water|terminology|" AnswerCount="1" CommentCount="2" ClosedDate="2015-08-08T13:41:05.400" ContentLicense="CC BY-SA 4.0" />
  <row Id="5334" PostTypeId="2" ParentId="5333" CreationDate="2015-08-08T08:46:54.333" Score="3" Body="&lt;p&gt;Water reclamation is the process of capturing, transporting and treating water so it can be be reused, particularly if the water is contaminated. Depending on the type of contamination treatment facilities can be a processing plant or a specially constructed/adapted system of biological wetlands with a slow flow of water through them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Re-using water is using water more than once regardless of whether it has been treated or not. For waste water to be reused it must first be reclaimed and treated.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-08-08T08:46:54.333" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5335" PostTypeId="2" ParentId="5332" CreationDate="2015-08-08T10:36:34.703" Score="16" Body="&lt;p&gt;Mountain ranges are usually formed as &lt;a href=&quot;https://en.wikipedia.org/wiki/Orogeny&quot; rel=&quot;noreferrer&quot;&gt;orogeny&lt;/a&gt; where tectonic plates collides, known as &lt;em&gt;convergent boundaries&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The continental plates have less density than the oceanic plates and the buoyancy results in that they are mostly above sea level. Continental sea floor is known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Continental_shelf&quot; rel=&quot;noreferrer&quot;&gt;continental shelf&lt;/a&gt;, but usually, it doesn't reach far from the coastline. Therefor the continental-oceanic boundaries often runs sub-parallel to the coastlines we see today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At convergent boundaries where oceanic crust and continental crust collides, the mountain ranges can therefor form right at the coastline. Vulcanism is also important in the process as volcanoes forms where oceanic crust is &lt;a href=&quot;https://en.wikipedia.org/wiki/Subduction&quot; rel=&quot;noreferrer&quot;&gt;subducted&lt;/a&gt; under the continental plates. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/p4M9p.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/p4M9p.gif&quot; alt=&quot;USGS&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some of the mountain ranges that today are located far from the coast, e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Uralian_orogeny&quot; rel=&quot;noreferrer&quot;&gt;the Urals&lt;/a&gt; are formed from earlier convergent boundaries between continental plates that today are incorporated in larger plates. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Convergent boundaries explains most of the mountain ranges (e.g the Andes, Himalaya, the Alps, Nihon Arupusu) but there are however some curious exceptions, e.g. the Scandinavian Mountains that are not located near any convergent boundary and might be the result of regional &lt;a href=&quot;http://www.lithosphere.info/papers/2009-Tecto-Ingrid-small.pdf&quot; rel=&quot;noreferrer&quot;&gt;uplift&lt;/a&gt;. However, there is an interesting ongoing discussion on how these processes work.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;This is a simplified answer that I hope inspire to further studies in tectonic and geology. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2015-08-08T10:50:15.670" LastActivityDate="2015-08-08T10:50:15.670" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5336" PostTypeId="1" CreationDate="2015-08-08T12:58:03.377" Score="7" ViewCount="275" Body="&lt;p&gt;Recently, we got the news that the western part of Nepal may be hit by a larger earthquake than that of April 25, because it did release all of its energy. During the earthquake, only the eastern part of Nepal was affected. So I want to know if Kathmandu, i.e. the central part of Nepal, could also be affected by the anticipated earthquake.&lt;/p&gt;&#xA;" OwnerUserId="3304" LastEditorUserId="28050" LastEditDate="2015-09-21T14:48:40.653" LastActivityDate="2015-10-09T11:47:32.030" Title="Will another big earthquake hit Kathmandu?" Tags="|geology|seismology|earthquakes|plate-tectonics|seismic-hazards|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5337" PostTypeId="1" AcceptedAnswerId="5350" CreationDate="2015-08-08T20:24:39.877" Score="7" ViewCount="177" Body="&lt;p&gt;I am comparing the climates of a handful of cities and I would like to find the average of all recorded yearly high and low temperatures, but all I'm able to find is the average of all monthly averages.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, if I look at climate data for Portland Oregon, it tells me that the average high temperature for the month of July is 81(F), but I know that the temperature regularly climbs into the 90s in the month of July (occasionally into the 100s). I know that for 2015 the highest recorded temperature in Portland was around 104(F), 2014 was 98(F) and 2013 was 93(F), which for this small sample would put the average annual high temperature at around 98(F).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where can I find this type of information?&lt;/p&gt;&#xA;" OwnerUserId="3306" LastEditorUserId="3306" LastEditDate="2015-08-10T19:15:36.787" LastActivityDate="2015-08-10T21:07:29.290" Title="Where can I find data for annual high and low temperatures?" Tags="|climate|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5338" PostTypeId="2" ParentId="5337" CreationDate="2015-08-09T01:12:58.783" Score="3" Body="&lt;p&gt;Have you tried the meteorological service in the US? My experience is most major weather stations record temperature and pressure at half hourly intervals 24/7. From these recordings daily maximum and minimum temperatures are then made available to the news services.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-08-09T01:12:58.783" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5339" PostTypeId="2" ParentId="5337" CreationDate="2015-08-09T01:17:59.440" Score="3" Body="&lt;p&gt;Try this website. You can pick out what todays highs and lows are and compare them to the climatological values.&#xA;&lt;a href=&quot;http://w2.weather.gov/climate/&quot; rel=&quot;nofollow&quot;&gt;http://w2.weather.gov/climate/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, state climatologists are good sources of information.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2015-08-09T01:17:59.440" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5340" PostTypeId="1" CreationDate="2015-08-09T03:21:16.940" Score="5" ViewCount="236" Body="&lt;p&gt;At what rate is loss of polar ice caps occurring? Do we have enough data to distinguish a meaningful trend? If we look at the trend since we have satellite measurements (40 years or so), is that enough?&lt;/p&gt;&#xA;" OwnerUserId="3033" LastEditorUserId="11908" LastEditDate="2019-03-13T05:17:55.863" LastActivityDate="2019-03-13T05:17:55.863" Title="At what rate are the polar ice caps shrinking?" Tags="|glaciology|ice-sheets|poles|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5341" PostTypeId="2" ParentId="5340" CreationDate="2015-08-09T11:37:30.890" Score="6" Body="&lt;p&gt;It's important to identify which ice.   Polar bears are arctic, and they hunt in large part on sea ice.   Arctic sea ice is decreasing and the most common point used for the disappearing arctic ice is the arctic sea ice minimum, meaning, the yearly low point, usually late September, so by that definition, we'd have an ice free arctic, you know, for a few days, but ice will form again as winter kicks in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That loss of arctic sea ice probably won't kill &quot;all&quot; the polar bears but it would likely kill a fair share of them, making their hunting more difficult.   This has already started and will probably continue to get worse.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, arctic sea ice has virtually nothing to do with flooding cities.    Flooding of cities has to do with melting of glaciers on land - essentially water that isn't currently in the oceans but as it melts it adds to the oceans.   Also, warming oceans expand, so warmer water increases flooding too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as the timing of the ice free arctic minimum, it's very hard to predict due to natural variability year to year, but 40 years doesn't seem far off - at least, looking at the trend, but there's also no guarantee the trend will be consistent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GGrYM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GGrYM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's gone from the 8 million square miles plus range into the early 70s into the 4s and 5s millions recently, dipping below 4 million in 2012 but rising back above that 2013-2014.  2015 we haven't hit the minimum yet so it only goes up to 2014 for yearly minimum.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If there's a mechanism that helps retain ice, such as cold water currents near the pole or a weakening of the warm Atlantic gulf stream, that could extend the ice quite a bit longer.   It could also happen quite a bit sooner than 40 years if we have a few more years like 2012 or 2007, each year showed a significant and unexpected reduction in minimum ice cover compared to previous years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A rather famous sea ice prediction was done by Professor Wieslaw Maslowski who in 2007 predicted we could see an ice free arctic by 2016 plus/minus 3 years - which Al Gore later quoted and said &quot;there is a study that says we &quot;could see&quot; an ice free arctic by 2013 and the deniers have loved referencing and misquoting that quote ever since.   I think Maslowski's predictions moved later a few years shortly after, but nobody remembers that.  Everybody remembers 2013, though he actually said 2016 plus/minus 3 years.    Ironically, we could still see a big sea ice drop by 2019 and in that case, Maslowski wouldn't be far from wrong, but his is still one of the most made fun of predictions in all of science.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maslowski's estimate was more aggressive than anyone else, but that doesn't mean he did bad work.   I've never looked into the specifics, but there's a ton of articles, some less friendly than others, on his 2016 plus/minus 3 years (which some people simply refer to as a failed 2013 prediction)  &lt;a href=&quot;http://www.theguardian.com/environment/earth-insight/2013/dec/09/us-navy-arctic-sea-ice-2016-melt&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's one&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also an ice free arctic in late summer means sea ice will still form in fall and stay through the winter and spring, so Polar bears will still likely have some sea ice to hunt from long after the &quot;ice free arctic&quot; happens, but the warming in general makes their survival more difficult and that's likely to continue and get worse.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as flooding cities, sea ice doesn't raise sea level, so that's a different subject.   That has more to do with the melting of glacial ice on land, primarily Greenland and Antarctica.    The melting of entire glaciers is on a whole different timescale and the melting of all of Antarctica might never happen, even in worst case global warming models, at least, it might not happen until Antarctic drifts off the south pole into warmer waters, but that's several million years away.    Parts of the Antarctic glacier could melt and parts have already melted, but only a teeny tiny percentage so far.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The IPCC forecasts for sea level rise includes both melting glaciers and warming and expanding oceans and they predict maybe 2-3 feet by 2100 (or 1-3 feet, depending on who you ask).   Compared to that, if all the glaciers melted, we could expect a sea level rise of about 230 feet, so clearly, nobody is predicting glaciers will melt completely anytime soon - not for many hundreds if not thousands of years, but those predictions are even more difficult.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But like sea ice predictions, glacier melting predictions are hard to estimate by trend cause the ice can give way more quickly or more slowly depending on a variety of factors.   Precise predictions are enormously difficult and not guaranteed to follow trends from the past.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Riict.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Riict.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's no shortage of articles to be found on sea level rise as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is, of-course, one of the problems that a good climate scientist faces.   &quot;When will that happen?&quot; - The honest answer is, we don't know, we can predict about when it's likely to happen, so the skeptic says &quot;so you don't know.&quot;- which misses the point entirely.    There's no question bad things will happen as a result of climate change.   It's just hard to predict exactly what will happen or exactly when.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2015-08-09T11:37:30.890" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5342" PostTypeId="1" CreationDate="2015-08-09T11:42:13.513" Score="4" ViewCount="1504" Body="&lt;p&gt;Last night the sky suddenly went yellow/pinkish colour. It looked like someone placed a transparent yellow/red plastic over our windows. I went outside and everything looked a pink/yellow colour, people where I live were confused. We thought it was a storm but there was no rain or anything after it. It was so weird, everything looked like it was tinted. It was almost like it looked iridescent or something?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What could it be? Could someone explain?&lt;/p&gt;&#xA;" OwnerUserId="3308" LastEditorUserId="183" LastEditDate="2015-08-11T13:54:51.550" LastActivityDate="2015-08-11T13:54:51.550" Title="Explanation of yellow/pinkish sky?" Tags="|meteorology|atmosphere|" AnswerCount="0" CommentCount="6" ClosedDate="2015-08-12T01:24:55.973" ContentLicense="CC BY-SA 3.0" />
  <row Id="5343" PostTypeId="2" ParentId="5328" CreationDate="2015-08-09T12:29:08.307" Score="3" Body="&lt;p&gt;&lt;strong&gt;tl;dr&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;If it's red, it's iron.&lt;/li&gt;&#xA;&lt;li&gt;If it's soil, it probably has iron even if it's not red.&lt;/li&gt;&#xA;&lt;li&gt;Therefore there's no point testing it for iron (in a simple way), because you can be confident it's there.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;I'd like to add a bit to Jezibelle's answer. First of all, you could do a simple chemical test to test for iron, but that would not give you much. Iron oxides on the surface are extremely insoluble in water. You would either have to use LOTS of soil and water to test it, or use acids that will dissolve it and then it's not a simple test anymore.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another reason is that assuming you do that test, it is going to be positive for iron. Andesite has iron in it. This and just about every other rock you can find have iron in it. Those that don't, are not red. The colour that you're seeing is enough proof that there's iron in it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now the question is which iron oxide is it. Pure hematite ($\ce{Fe2O3}$) is deep dark red. Pure goethite ($\ce{FeO(OH).H2O}$) is yellow. But then you have everything in between, and mixtures (given the general name: limonite). Now remember, iron is not the only constituent of soil. Silicon is the most abundant metal in soils, followed by aluminum, sodium, calcium, magnesium and potassium (not necessarily in that order). These elements can combine with iron to form stuff that doesn't even have to be red. It can be grey, black, green and everything in between.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-08-09T12:29:08.307" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5344" PostTypeId="1" CreationDate="2015-08-09T19:05:26.507" Score="9" ViewCount="1479" Body="&lt;p&gt;What is the maximum thickness of limestone layers on earth?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Limestone or any other biochemical sedimentary rocks, for example chalk or coral reefs.) &lt;/p&gt;&#xA;" OwnerUserId="3310" LastEditorUserId="725" LastEditDate="2015-08-10T12:38:00.743" LastActivityDate="2015-08-10T12:38:00.743" Title="where are the thickest limestone layers on earth ? (CaCO3)" Tags="|plate-tectonics|sedimentology|stratigraphy|biogeochemistry|limestone|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="5345" PostTypeId="1" CreationDate="2015-08-10T03:40:52.223" Score="6" ViewCount="110" Body="&lt;p&gt;I am applying the Canadian Fire Weather Index (FWI) on the Forest Fire Warning System of my laboratory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My problem is in calculating the Fine Fuel Moisture Code (FFMC), the Duff Moisture Code (DMC) and the Drought Code (DC) - 3 indicators for calculating FWI - the FWI has to use the values from the previous day as initial indexes. So, &lt;strong&gt;How can I find the initial indexes for the first day of calculation?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="3311" LastEditorUserId="2470" LastEditDate="2015-08-10T06:06:32.787" LastActivityDate="2015-08-10T06:06:32.787" Title="Initial indexes for calculating the Fire Weather Index (in the Canadian Forest Fire Weather Index System)" Tags="|weather-forecasting|forest|fossil-fuel|soil-moisture|drought|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5346" PostTypeId="1" AcceptedAnswerId="5348" CreationDate="2015-08-10T09:01:16.270" Score="5" ViewCount="2249" Body="&lt;p&gt;I just asked myself what is the role of the mountains on our planet earth? Well there's a well known role for the climate and weather.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But is there a kind of physical or geological role? What would happen if our earth lacks the mountains on it? Will we have more earth &quot;Movements&quot; (earthquakes, tectonics...) i suppose erosion will be much heavier then it is now. And therefore i suppose that human life in such a planet would be impossible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the Answers i would like to consider two scenarios:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Earth as we know but without mountains (mountains have never been&#xA;formed or don't exist at all)&lt;/li&gt;&#xA;&lt;li&gt;What will happen if the Mountains would just been taken away?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Well i would like to get some kind of scientific answer from a geological point of view!&lt;/p&gt;&#xA;" OwnerUserId="3321" LastEditorUserId="725" LastEditDate="2015-08-10T12:38:18.487" LastActivityDate="2015-08-15T18:42:46.870" Title="What would change if our earth lacks mountains?" Tags="|geophysics|geology|seismology|plate-tectonics|mountains|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5347" PostTypeId="1" CreationDate="2015-08-10T10:44:51.590" Score="8" ViewCount="207" Body="&lt;p&gt;This summer in the south of France we have had two hot months with 29 days over 30'C, while the average maximum is 26'C in July. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Normally there are violent storms with lightening up to 20 times a minute, and this year in two months we have had 20-30mm of precipitation rather than the average of 120mm, and there hasn't been any thunder and lightning since the 15th of june.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am confused why we have only had meek drizzly rainfall, because of weak cold fronts, insufficient moisture from the east, did the high heat cause the rain to not condensate in the high atmosphere?&lt;/p&gt;&#xA;" OwnerUserId="3315" LastActivityDate="2017-09-08T13:15:41.857" Title="How can there be a hot summer with rain and no thunderstorms and lightning?" Tags="|atmosphere|precipitation|rainfall|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5348" PostTypeId="2" ParentId="5346" CreationDate="2015-08-10T12:11:09.917" Score="6" Body="&lt;p&gt;Well, mountains are not a cause. Mountains are an effect. It's not that we have earthquakes because we have mountains. We have mountains because we have earthquakes.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Earth as we know but without mountains (mountains have never been formed or don't exist at all)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So by saying that mountains never existed at all, you are implying there are no tectonics. That would be a sad thing - one of the things that make Earth so alive and interesting &lt;em&gt;is&lt;/em&gt; the fact that we have plate tectonics. Go and have a look on Mars, the Moon, etc. There are no active tectonics there are those are dead places.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What will happen if the Mountains would just been taken away?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They would just form again. First of all, there would be the effect of isostatic rebound. When you take away a certain mass from an elastic thing, that thing bounces back up. When you're sleeping on your bed, there is a dent in it. When you get up, it springs right up. This will happen also in the Earth. It is happening actually as we speak - certain places in the world (Scandinavia is one example) that are slowly rising because the huge ice sheets that existed during the last ice age melted. That said, India is still colliding into Asia and the Mediterranean is still closing so you would get more Himalayas and Alps. Plates are still subducting so you you will get volcanic arcs such as the Andes or Japan. It will take some time, but the mountains will come back.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-08-10T12:11:09.917" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5349" PostTypeId="2" ParentId="5344" CreationDate="2015-08-10T12:37:27.800" Score="6" Body="&lt;p&gt;Reading your comments I see that you're asking:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;so could we find for example 1km high limestone layers on earth ?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The answer is definitely yes. Here's an example of a stratrigraphic geological section from Israel:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ImGfs.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ImGfs.png&quot; alt=&quot;Gvirtzman&quot;&gt;&lt;/a&gt;&#xA;&lt;sup&gt;source: Chronostratigraphic table and subsidence curves of southern Israel, Gvirtzman 2004, &lt;em&gt;Israel Journal of Earth Sciences&lt;/em&gt;, 53&lt;/sup&gt;&#xA;You can see that in the north of the country there is an almost entirely continuous section of &quot;platformal carbonates&quot; which is just a fancy name for limestones. That's 5 kilometres of limestone. And I'm pretty sure that's not the deepest - that's only the one I personally know.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's a sedimentary basin where you can drill and still find fossil-bearing limestones deep down. This gets even better if you start adding tectonics to this. Plate movements can do funny stuff to rocks, including burying them really deep. If you take limestones and do that to them, you actually transform them into marble. Basically marble (proper) is limestone buried deep and cooked. And by deep I mean really deep. Some marbles from the Alps are known to come from more than 100 kilometres deep! Note that I'm not saying it's limestone all the way down, but there are chucks of marble (formerly limestone) down there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to be really extreme, there is an &lt;a href=&quot;http://www.nature.com/nature/journal/v358/n6389/abs/358745a0.html&quot; rel=&quot;noreferrer&quot;&gt;article&lt;/a&gt; where the authors say:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...carbonate sediments were subducted into the upper mantle...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Upper mantle is 200-300 kilometres deep. And you know what? That's only the ones we know of. Who knows, there might be some limestones that were subducted all the way down to the core-mantle boundary, almost 3000 kilometres deep.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-08-10T12:37:27.800" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5350" PostTypeId="2" ParentId="5337" CreationDate="2015-08-10T21:07:29.290" Score="4" Body="&lt;p&gt;You can find this data from &lt;a href=&quot;http://www.ncdc.noaa.gov/&quot; rel=&quot;nofollow&quot;&gt;NCDC&lt;/a&gt;.  You can find the data for &lt;a href=&quot;http://www.ncdc.noaa.gov/cdo-web/datasets/ANNUAL/locations/CITY:US410014/detail&quot; rel=&quot;nofollow&quot;&gt;Portland, OR here&lt;/a&gt;.  These are &lt;a href=&quot;http://www.ncdc.noaa.gov/cdo-web/search?datasetid=ANNUAL&quot; rel=&quot;nofollow&quot;&gt;annual summaries (ancsum)&lt;/a&gt; and for Portland they have extreme minimum daily temperature (EMNT) and extreme maximum daily temperature (EMXT) dating back to 1910.  From the linked page you can request data in various formats and select the date range and the specific variables you want.  They will put together the requested data and email you with a link to download it.  Here is some example data from the dataset:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201301  55  23&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201302  61  30&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201303  77  29&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201304  78  36&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201305  85  40&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201306  97  49&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201307  92  53&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201308  91  57&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201309  95  47&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201310  74  32&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201311  60  24&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201312  57  12&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201401  58  25&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201402  58  19&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201403  69  32&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201404  83  39&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201405  91  42&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201406  85  48&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201407  99  54&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201408  99  54&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201409  94  51&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201410  85  47&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201411  63  26&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201412  64  21&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201501  60  24&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201502  64  32&#xA;COOP:356751 PORTLAND INTERNATIONAL AIRPORT OR US    201503  73  30&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;These are extreme max/min temperatures for each month, so for this station you have annual maximums of 97 F and 99 F for 2013 and 2014.  You have annual minimums of 12 F and 19 F for the same two years.  There are multiple stations and they have varying temporal coverage.  You can request this data for each of the cities that interest you.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-08-10T21:07:29.290" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5351" PostTypeId="2" ParentId="4249" CreationDate="2015-08-10T23:09:05.813" Score="0" Body="&lt;p&gt;This isnt an answer, but may point you in the right direction&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://eost.u-strasbg.fr/semipgs/pres_Walter_04_03_08.pdf&quot; rel=&quot;nofollow&quot;&gt;http://eost.u-strasbg.fr/semipgs/pres_Walter_04_03_08.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3317" LastActivityDate="2015-08-10T23:09:05.813" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5352" PostTypeId="2" ParentId="5347" CreationDate="2015-08-11T00:21:00.540" Score="6" Body="&lt;p&gt;This is an El Nino summer, and a very strong one and a very weird one at that. Weather patterns are messed up world-wide. Apparently a stable high pressure cell has set up that oscillates back and forth between just east of Barcelona to eastern Europe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;France suffers when that high pressure cell is just east of Barcelona. That high pressure cell off Barcelona means France is in that thick of it. Moderately high temperatures and low humidity rule the day. The chance of rain is drastically reduced, and the chance of abnormal high temperatures is drastically increased.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;France suffers even more when that high pressure cell migrates to the northeast. Now the clockwise rotation of the high pressure cell carries extremely hot and extremely dry air from the Sahara towards France. If on the very odd chance that you do see clouds, and on the odder chance that you do see rain falling from a cloud, the odds are that you'll see the rain disappearing halfway to the ground.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-08-11T00:21:00.540" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="5353" PostTypeId="1" AcceptedAnswerId="5359" CreationDate="2015-08-11T01:18:38.010" Score="4" ViewCount="64" Body="&lt;p&gt;I'm working on the rotation of the state of stress using the book &lt;a href=&quot;https://books.google.com/books?id=heJSAwAAQBAJ&amp;amp;pg=PA100&amp;amp;source=gbs_toc_r&amp;amp;cad=4#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;nofollow&quot;&gt;Geodynamics of Turcotte&lt;/a&gt; page 101. The 2D coordinate system $x'$ and $y'$ is inclined at an angle $\phi$ with respect to the $x$, $y$ coordinate system (see Figure 2.14).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The force in the $y$-direction on face $AO$ is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ \sigma_{yy}AO $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and the force in the $y$-direction on face $OB$ is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ \sigma_{xy}OB $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The force in the $y$-direction on face $AB$ is &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ -\sigma_{x'x'}AB\cdot\sin\theta -\sigma_{x'y'}AB\cdot\cos\theta$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't understand why the force in the $y$-direction on face $AB$ is equal to the above equation? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think the negative signs are there because the stresses are not oriented in the same direction than the $y$-direction. I don't know why it is necessary to subtract the two lengths.&lt;/p&gt;&#xA;" OwnerUserId="3161" LastEditorUserId="5510" LastEditDate="2016-02-26T18:15:57.390" LastActivityDate="2016-02-26T18:15:57.390" Title="State of Stress in rotated 2D system" Tags="|geophysics|geodynamics|structural-geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5354" PostTypeId="2" ParentId="5332" CreationDate="2015-08-11T05:53:09.153" Score="0" Body="&lt;p&gt;When two plates collide, if the  one going down, if it is already under the sea, produces a depression which naturally will be filled with sea water whereas the other plate is raised by the collision originating mountains One typical example is the Andes. &lt;/p&gt;&#xA;" OwnerUserId="3318" LastActivityDate="2015-08-11T05:53:09.153" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5355" PostTypeId="1" AcceptedAnswerId="5356" CreationDate="2015-08-11T10:00:53.190" Score="12" ViewCount="424" Body="&lt;p&gt;The vertical profile of horizontal windspeed is often given by the so-called &quot;log-law&quot;:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$u(z)=(u^*/k)\ln(z/z_0),\ \mathrm{for}\  z&amp;gt;z_0,$$   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;which can be found &lt;a href=&quot;http://mstudioblackboard.tudelft.nl/duwind/Wind%20energy%20online%20reader/Static_pages/wind_shear.htm&quot;&gt;here&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As can be seen from the equation, when $z=z_0$, $u(z)=0$. But what happens below $z_0$? If we continue to use the same equation, for $z&amp;lt;z_0$, $u(z)$ becomes negative and changes direction, which seems absurd. &lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorUserId="64" LastEditDate="2015-08-11T20:50:02.790" LastActivityDate="2015-08-18T11:47:20.897" Title="Wind profile below the aerodynamic roughness length" Tags="|meteorology|atmosphere|wind|turbulence|planetary-boundary-layer|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5356" PostTypeId="2" ParentId="5355" CreationDate="2015-08-11T13:13:22.503" Score="10" Body="&lt;p&gt;The key text here is &quot;for $z&amp;gt;z_0$&quot;.  It's telling you that, while you can evaluate the equation for other values of $z$, outside of that range the equation is not a valid description of the physical system.  The equation could be written piece-wise to be complete:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$u(z) = \begin{cases} (u_*/k) \ln(z/z_0)&amp;amp; z&amp;gt;z_0 \\ 0 &amp;amp; z\le z_0\end{cases}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But this doesn't really add anything useful.  In practice, the &quot;log-law&quot; is used to describe the wind profile over 10s of metres and values of $z_0$ range from 1 mm to 2 m, so values of $z$ are likely to be in the valid region.  If you do need to make calculations that close to the surface (in the interfacial sublayer) then you'll need a different equation anyway.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2015-08-11T13:13:22.503" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5357" PostTypeId="1" CreationDate="2015-08-11T14:15:04.393" Score="15" ViewCount="972" Body="&lt;p&gt;I would like to be able to point to a piece of rock and say that is rock type &lt;em&gt;such and such&lt;/em&gt;. I have tried learning but it literally seems like an endless list of types and sub types and the pictures don’t really seem to help me. Short of a person taking me out and physically handing me rock specimens, is there any easy way to self learn the different types?&lt;/p&gt;&#xA;" OwnerUserId="3196" LastEditorUserId="4487" LastEditDate="2015-10-25T00:26:53.533" LastActivityDate="2017-03-25T12:25:15.173" Title="How to learn the different types of rock" Tags="|geology|rocks|petrology|reference-request|teaching|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5358" PostTypeId="2" ParentId="5357" CreationDate="2015-08-11T14:43:54.387" Score="11" Body="&lt;p&gt;The best way to learn about rock types is to handle rock specimens guided by an experienced geologist.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By handling rock specimens you get to feel the weight of the rock, its roughness or smoothness or if it feels slippery, soapy, glassy, firm or crumbly. Is it weak or strong? You will also be able to better see the colours in the rock, the sizes of the grains of minerals, the way the rock breaks, its cleavage. You can test its hardness. If you have a piece of unglazed white porcelain you can do a streak colour test.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All these sorts of things can help you identify different rock types.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, the same rock type can look slightly different in other parts of the world, because of geological and environmental processes that rocks experience in different parts of the world. This is particularly so if the rock is deeply weathered.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Learning the different rock types, alone from books and pictures is a difficult way to learn, befriend a geologist, you'll learn more quickly and it will be more enjoyable.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-08-11T14:43:54.387" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5359" PostTypeId="2" ParentId="5353" CreationDate="2015-08-11T15:21:39.960" Score="1" Body="&lt;p&gt;You are correct in your intuition regarding the signs of the forces.  The reason for two terms is due to the direction of the force.  The y-direction is not aligned with the face AB (it is aligned with y') so the force on this face is a combination of the forces normal to AB ($-\sigma_{x'x'}AB$) and the force along the face ($-\sigma_{x'y'}AB$).  Because the question wants only the force in the y-direction, we need to find the projection of these forces along that direction. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the angle between the coordinate axes is $\theta$, then the contribution of $-\sigma_{x'x'}AB$ in the y-direction is $-\sigma_{x'x'}AB\sin\theta$ and the contribution of $-\sigma_{x'y'}AB$ in the y-direction is $-\sigma_{x'y'}AB\cos\theta$, thus the total force in the y-direction is the sum of these contributions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$-\sigma_{x'x'}AB\sin\theta-\sigma_{x'y'}AB\cos\theta$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a quick figure to help visualize the geometry:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jOuIR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jOuIR.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-08-11T15:21:39.960" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5360" PostTypeId="2" ParentId="4940" CreationDate="2015-08-11T19:22:32.850" Score="7" Body="&lt;p&gt;You are correct when you say it is mostly a matter of getting your eye in and getting used to the shapes and types of rock you need to be looking at. Hopefully however the below information will help you find a few more fossils or at least be of interest to you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main fossil bearing beds in Lyme Regis are from the Jurassic period and formed in a warm sea, hence the marine fossils.The Jurassic strata (layers of rock) in this area are mainly composed of grey limestones, shales and marls (lime rich mudstones).  These are the rocks you want to focus on when searching for fossils (see image below taken facing church cliffs).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KIRSF.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KIRSF.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The majority of the very well preserved ammonites are found in the limestone and can be found inside limestone nodules or lying loose on the beach. This rock is very hard and will require a good geological hammer and maybe a chisel to split. This is often easiest if you find a nodule with lines of weakness or cracks that you can split it along. It is also a good idea to look for signs that the rock contains a fossil before trying to break it, part of a fossil may be visible on the surface of the rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can identify the limestone by it's lighter grey colour and hardness, it should be quite hard to break without a hammer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bSsiw.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bSsiw.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is however possible to find ammonites in the shale and mudstones, the ammonites in these however tend to be less well preserved. These rocks are typically a darker grey and very easy to break. However there are other fossils that can be found in these shales, including belemnite rostrum (belemnite guards). These bullet shaped fossils are from an ancient relative of the squid and the cuttlefish and are very abundant in certain areas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally there are very soft mudstone beds out near Church Cliffs that you can walk across along the foreshore and are rich in belemnites, as well as pyrite (fools gold) and pyritised ammonites. These are formed when the original shell is replaced by pyrite in low oxygen conditions such as deep on a muddy sea floor and can be recognised by their golden colour and shine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All the best with your fossil hunting!&lt;/p&gt;&#xA;" OwnerUserId="3322" LastActivityDate="2015-08-11T19:22:32.850" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5361" PostTypeId="1" CreationDate="2015-08-12T01:17:10.907" Score="7" ViewCount="131" Body="&lt;p&gt;It appears that the &lt;a href=&quot;http://www.swan.tudelft.nl/&quot;&gt;SWAN wave model&lt;/a&gt; is adept in shallow water and coastal regions. See for example &lt;a href=&quot;http://met.no/filestore/metno_report_18_2010.pdf&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;http://polar.ncep.noaa.gov/waves/nwps/&quot;&gt;here&lt;/a&gt;. What makes SWAN more suitable in these regions than other wave models like WAVEWATCH? In checking the &lt;a href=&quot;http://swanmodel.sourceforge.net/features/features.htm&quot;&gt;feature list here&lt;/a&gt;, I was not able to immediately find features that do not exist in other wave models.&lt;/p&gt;&#xA;" OwnerUserId="2645" LastActivityDate="2015-08-12T01:17:10.907" Title="What makes the SWAN wave model suitable for coastal regions?" Tags="|waves|wave-modeling|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5362" PostTypeId="1" AcceptedAnswerId="5366" CreationDate="2015-08-12T01:45:14.223" Score="7" ViewCount="1225" Body="&lt;p&gt;Is this true?&#xA;&quot;If there are no weather front or severe weather systems, then the dew point within a single day is fairly constant, no matter how large the day/night temperature variation.&quot;&lt;/p&gt;&#xA;" OwnerUserId="3325" LastActivityDate="2015-08-12T14:26:38.770" Title="Dew point variation in a day" Tags="|meteorology|temperature|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5363" PostTypeId="2" ParentId="5362" CreationDate="2015-08-12T03:55:33.163" Score="2" Body="&lt;p&gt;From a review of weather observations, that statement is false.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Below are  the synoptic weather maps for Australia for 11 August 2015 and  &lt;a href=&quot;http://www.bom.gov.au/australia/charts/synoptic_col.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;12 August 2015&lt;/a&gt;. There are no weather fronts, or adverse weather in the western two-thirds of the continent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3BHgI.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3BHgI.png&quot; alt=&quot;Aus synopic map 20150811&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6Tjx3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6Tjx3.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alice Springs (lat:-23.8, long: 133.89) is in the centre of the continent. It's &lt;a href=&quot;http://www.bom.gov.au/products/IDD60801/IDD60801.94326.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;weather observations&lt;/a&gt; for 11 August 2015 reveal the temperature ranged between $5.8$ $^oC$ and $26.0$ $^oC$ and the dew point  range was between $-18.8$ $^oC$ and $-2.5$ $^oC$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly for &lt;a href=&quot;http://www.bom.gov.au/products/IDD60901/IDD60901.94120.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Darwin&lt;/a&gt; (lat: -12.42, long: 130.89), which is located on the coast in the sub tropics, in the central north of the country, the temperature range for 11 August 2015 was $19.7$ $^oC$ to $30.1$ $^oC$, while the dew point range was $15.4$ $^oC$ to $19.8$ $^oC$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.bom.gov.au/products/IDW60901/IDW60901.94610.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Perth&lt;/a&gt; (lat: -31.93, long: 115.98), on the southern western coast has a temperate Mediterranean climate. It's temperature range was $10.2$ $^oC$ to $17.6$ $^oC$ and the dew point range was $5.7$ $^oC$ to $11.7$ $^oC$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.bom.gov.au/products/IDS60901/IDS60901.94672.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Adelaide&lt;/a&gt; (lat: -34.95, long: 138.52), on the southern coast, in the centre region , also has a temperate climate and its temperature ranged from $7.6$ $^oC$ to $15.4$ $^oC$ and the dew point range was $-0.3$ $^oC$ to $8.5$ $^oC$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lastly, &lt;a href=&quot;http://www.bom.gov.au/products/IDQ60901/IDQ60901.94578.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Brisbane&lt;/a&gt; (lat: -27.39, long: 153.13) which is on the east coast  had temperatures between $8.2$ $^oC$ and $21.9$ $^oC$ and the dew point varied between $6.9$ $^oC$ and $15.8$ $^oC$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All these weather observations show significant variance in the dew point for these locations given the respective temperature ranges and the lack of weather fronts and adverse weather systems.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-08-12T03:55:33.163" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5364" PostTypeId="1" AcceptedAnswerId="5367" CreationDate="2015-08-12T11:55:15.730" Score="9" ViewCount="149" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Storegga_Slide&quot; rel=&quot;noreferrer&quot;&gt;Storegga Slide&lt;/a&gt; was a catastrophic underwater landslide that occurred off the coast of Norway about 8,200 years ago. This &lt;a href=&quot;https://www.youtube.com/watch?v=Nomlo8X58PY&quot; rel=&quot;noreferrer&quot;&gt;YouTube clip&lt;/a&gt; shows simulations that indicate that this slide resulted in landslides in the 10's of metres across the surrounding shorelines, including the Norwegian coast, Greenland, Iceland, Shetlands, Orkneys, Britain etc and by several accounts, it wiped out the now submerged North Sea land-bridge known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Doggerland&quot; rel=&quot;noreferrer&quot;&gt;Doggerland&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A possible cause from the Wikipedia article (linked above) is:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A likely triggering mechanism is thought to be an earthquake causing a catastrophic expansion of methane hydrates.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This earthquake scenario is also mentioned in &lt;a href=&quot;https://youtu.be/q2jkqcEeIlY&quot; rel=&quot;noreferrer&quot;&gt;this YouTube clip&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What evidence is there of a seismic trigger of the Storegga Slide?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user2872" LastEditorDisplayName="user2872" LastEditDate="2015-08-12T21:03:52.283" LastActivityDate="2015-08-12T22:04:59.587" Title="Evidence of a seismic trigger of the Storegga Slide ~8.2ka" Tags="|seismology|tsunami|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5365" PostTypeId="1" CreationDate="2015-08-12T12:31:28.727" Score="4" ViewCount="452" Body="&lt;p&gt;Let's just imagine that there are no continents that span the equator like Africa and South America and also no large Equatorial Islands like those in Indonesian archipelago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So that between latitude 10 north and 10 south there are no substantial landmasses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Holding Earth's other physical parameters constant would there be a circum-equatorial current like Antarctic Circumpolar Current?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would it be stronger/faster than the current Pacific Equatorial Current? How strong would it be?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could a wooden sail ship cross the current from North to sail to South?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the first part of the question. The second part of question would be to ask the effect of a continous equatorial current on the world climate.&lt;/p&gt;&#xA;" OwnerUserId="3327" LastEditorUserId="2426" LastEditDate="2015-08-12T18:13:27.620" LastActivityDate="2015-08-12T18:13:27.620" Title="If there were no continent that spanning between the North and South Hemispheres would there be a Circum-equatorial Current?" Tags="|ocean-currents|" AnswerCount="0" CommentCount="8" ClosedDate="2015-08-12T22:33:56.300" ContentLicense="CC BY-SA 3.0" />
  <row Id="5366" PostTypeId="2" ParentId="5362" CreationDate="2015-08-12T14:26:38.770" Score="0" Body="&lt;p&gt;If you consider a closed system, this will be true, as dewpoint is related to the absolute moisture which is not a function of temperature.  However, as Fred's answer demonstrates, the atmosphere is not a closed system.  Even devoid of fronts and severe weather there are still pressure gradients which result in wind.  Wind advects moisture and so if there is wind the moisture (dew point) can change.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore if we consider surface fluxes that statement becomes even less true.  With no advection if we have vegetation or standing water on the surface we can increase the dew point just through evapotranspiration. &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-08-12T14:26:38.770" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5367" PostTypeId="2" ParentId="5364" CreationDate="2015-08-12T21:31:02.520" Score="7" Body="&lt;p&gt;Scandinavia experienced a lot of earthquakes due to post glacioisostatic rebound 10 - 7 ka. The most likely trigger for the Storegga Slide was a strong earthquake or a series of earthquakes. However, large sediment input from glaciation rather than earthquakes are the causes of the unstable slope. Release of overpressured gas hydrates was the driving force for the violent development of the slide. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It is reasonable to relate the period with strong earthquakes with&#xA;  rapid  rebound  and  the  triggering  of  the  Storegga  Slide.&#xA;  Recent modelling shows that the seismic energy can induce&#xA;  ground shaking that lasts longer than previously assumed in&#xA;  the deep sedimentary Møre basin (Lindholm et al., 2005). In&#xA;  the Storegga region the isostatic deformation and reactivation  of  Late  Jurassic–Early  Creteaous  faults  because  of sediment loading on the North Sea Fan probably caused an elevated earthquake level. [...] The combined effects of excess pore pressure, exposure of ooze, relative steep slopes 10–20&amp;deg;&#xA;  and to the vicinity of potential  earthquake  centres  favour  an  initial  slide  in  the distal  area. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Bryn et al. (2005)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Bryn, P., et al. &quot;The Storegga Slide complex; repeated large scale sliding in response to climatic cyclicity.&quot; Submarine mass movements and their consequences. Springer Netherlands, 2003. 215-222.&lt;/li&gt;&#xA;&lt;li&gt;Bryn, P., et al. &quot;Explaining the Storegga slide.&quot; Marine and Petroleum Geology 22.1 (2005): 11-19.&lt;/li&gt;&#xA;&lt;li&gt;Lindholm, C., et al. &quot;Probabilistic and deterministic seismic hazard results and influence of the sedimentary Møre Basin, NE Atlantic.&quot; Marine and petroleum geology 22.1 (2005): 149-160.&lt;/li&gt;&#xA;&lt;li&gt;Berndt, C., et al. &quot;Submarine slope-failure offshore Norway triggers rapid gas hydrate decomposition.&quot; 4th int. conf. on gas hydrates proc., Yokohama, Japan. 2002.&lt;/li&gt;&#xA;&lt;li&gt;Bungum, H., Lindholm, C. and J. I. Faleide. &quot;Postglacial seismicity offshore mid-Norway with emphasis on spatio-temporal–magnitudal variations.&quot; Marine and Petroleum Geology 22.1 (2005): 137-148.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2015-08-12T22:04:59.587" LastActivityDate="2015-08-12T22:04:59.587" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5368" PostTypeId="2" ParentId="5355" CreationDate="2015-08-13T08:16:55.530" Score="7" Body="&lt;p&gt;$z_0$ is a theoretical construct that, while useful in its intended uses, cannot be thought of in too much detail as a physical reality. When using a log law to describe wind speed, it represents the distance above the surface at which that log curve decreases to zero. However, if a measurement of speed were made at this height, it would be unlikely to be zero - more detailed, finer-scaled processes dominate here.&#xA;(I don't know wind modelling, but by analogy from water I'm guessing a that thin linear boundary layer exists between the ground and the point at which the log curve becomes dominant)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In practice the log-law approach for wind speed is used when dealing with speeds large distances (tens of metres) above the surface, and is not applicable when $z$ approaches $z_0$. Far more detailed techniques would be needed in this realm.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2015-08-13T08:16:55.530" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5369" PostTypeId="2" ParentId="533" CreationDate="2015-08-13T16:09:19.037" Score="1" Body="&lt;p&gt;Assuming you want to plot a diagram with your computer, the RAOB Program is the most versatile Skew-T plotting program available.  It's easy to use and fully menu driven.&lt;/p&gt;&#xA;" OwnerUserId="3330" LastActivityDate="2015-08-13T16:09:19.037" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5370" PostTypeId="2" ParentId="4249" CreationDate="2015-08-14T09:55:17.500" Score="4" Body="&lt;p&gt;One way to estimate the upper limit of the magnitude is through observations and measurements.  According to the article &lt;a href=&quot;http://cdn.intechopen.com/pdfs-wm/26243.pdf&quot; rel=&quot;nofollow&quot;&gt;Seismic Wave Interactions Between&#xA;the Atmosphere - Ocean - Cryosphere&#xA;System and the Geosphere in Polar Regions&lt;/a&gt;, a couple of difficulties with determining how large ice-quakes can get, asides from the regions not monitored, are due to the sources of the recorded motion and delineating cryoseismic and tectonic observations. From the article:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Such cryoseismic sources include the movements of ice sheets, sea-ice,&#xA;  oceanic tide-cracks, oceanic gravity waves, icebergs and the calving fronts of ice caps. &lt;strong&gt;At&#xA;  times, it can be hard to distinguish between the waveforms generated by local tectonic&#xA;  earthquakes and those of ice-related phenomena.&lt;/strong&gt; &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, in the Scientific American article &lt;a href=&quot;http://www.scientificamerican.com/article/long-overlooked-ice-quakes-data-provides-insights-into-calving-glaciers/&quot; rel=&quot;nofollow&quot;&gt;Long-Overlooked &quot;Ice Quakes&quot; Data Provides Insights into Calving Glaciers&lt;/a&gt;, they can be identified by their location and unique waveforms identified relatively recently. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the first article, unlike tectonic events, cryoseismic (= ice-quake) events are seasonal and heavily climate-dependent, with the article detailing that observations have shown that in polar regions &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;microseism amplitude is attenuated during local winter for both primary and&#xA;  secondary microseisms&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Observations of body-wave magnitudes (Mb) between 1987-2007 in an Antarctic station were up to 6.5-7.0&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A recent observation are the related 'glacial quakes', which generated log period surface waves (greater than 25s) which, according to the article, is&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;equivalent in strength to those radiated by&#xA;  standard magnitude five earthquakes, and were observable worldwide. The glacial&#xA;  earthquakes radiated little high-frequency energy, which explains why they were not&#xA;  detected or located by traditional earthquake-monitoring systems. These events are two&#xA;  magnitude units larger than previously reported seismic phenomena associated with&#xA;  glaciers, a size difference corresponding to a factor of 1,000 in a seismic moment.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Similar observations have been made in the Greenland ice sheet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NOAA has some sample cryoseismic traces on their PMEL Acoustics page &lt;a href=&quot;http://www.pmel.noaa.gov/acoustics/sounds/bloop.html&quot; rel=&quot;nofollow&quot;&gt;Icequakes&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerDisplayName="user2872" LastActivityDate="2015-08-14T09:55:17.500" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5371" PostTypeId="1" CreationDate="2015-08-14T14:51:02.777" Score="13" ViewCount="676" Body="&lt;p&gt;In an quiz app I surprisingly learned that aluminium has a larger abundance then iron. When researching this on Wikipedia, I found &lt;a href=&quot;https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth&amp;#39;s_crust&quot;&gt;this article&lt;/a&gt;,&#xA;which also had the comment: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Note that numbers are estimates, and they will vary depending on source and method of estimation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Now I wonder what methods exist and were used to estimate this? The only idea I had, that they took probes from different places and averaged the result, but that sounds like a very vague guess, because you would need a lot of probes from different places and depths (up to 50km deep), so I guess they used another method to estimate this. If somebody knows how the numbers are estimated, can he also say how accurate this estimations are?&lt;/p&gt;&#xA;" OwnerUserId="3334" LastEditorDisplayName="user20559" LastEditDate="2021-05-14T10:46:11.783" LastActivityDate="2021-05-14T10:46:11.783" Title="How is abundance of elements in the Earth's crust estimated?" Tags="|geology|geochemistry|crust|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5373" PostTypeId="2" ParentId="5301" CreationDate="2015-08-14T18:50:42.523" Score="0" Body="&lt;p&gt;I think that if you just want the insolation (at the top of the atmosphere), then you can just follow the argument here:&lt;a href=&quot;https://en.wikibooks.org/wiki/Climate_Change/Science/Distribution_of_Insolation&quot; rel=&quot;nofollow&quot;&gt;Climate Change/Science/Distribution of Insolation (Wikimedia)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then you can make some assumption about the radiative transfer through the atmosphere to get at the temperature. &lt;/p&gt;&#xA;" OwnerUserId="3339" LastEditorUserId="6093" LastEditDate="2016-10-10T06:31:20.850" LastActivityDate="2016-10-10T06:31:20.850" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5374" PostTypeId="2" ParentId="4371" CreationDate="2015-08-14T20:05:24.657" Score="3" Body="&lt;p&gt;These two links were the sources I used when researching this question: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Mapping critical loads of nitrogen deposition for aquatic ecosystems in the Rocky Mountains&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://co.water.usgs.gov/publications/non-usgs/Nanus_2012.pdf&quot; rel=&quot;nofollow&quot;&gt;http://co.water.usgs.gov/publications/non-usgs/Nanus_2012.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Approaches for estimating critical loads of nitrogen and sulfur deposition for Forest Ecosystems of U.S. Federal Lands&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nrs.fs.fed.us/pubs/gtr/gtr_nrs71.pdf&quot; rel=&quot;nofollow&quot;&gt;http://www.nrs.fs.fed.us/pubs/gtr/gtr_nrs71.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It looks like there are actually several different approaches which can be used when calculating the Critical loads, and depending on the approach the factors considered change: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Empirical (Regression) modeling: These are generally based on observations of ecosystem response (this is tracked off of Foliage, lichens, or soils) and tracked to a given deposition level. This is generally calculated in one area, and applied elsewhere. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Simple mass-balance models: estimating a net loss or accumulation of nutrients based in the in/out of a system for that nutrient. These are basically steady state models and are measured generally on base cations or nitrogen. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Dynamic models using a mass balance approach which incorporates internal feedbacks over time. This is a combination of the two and is generally used where there is an abundance of existing data. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The links contain further information which may be more helpful. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &quot;Wolfe, A.P., Baron, J.S., Cornett, R., 2001. Anthropogenic nitrogen deposition induces rapid change in alpine lakes of the Colorado Front Range (USA). Journal of Paleolimnology 25, 1e7.&quot; as cited in the first article I linked, This excess N (caused by exceeding the critical load) can result in acidification and nutrient enrichment, increasing primary productivity in high-elevation lakes and streams, and altering diatom community structures that form the base of the food web –&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The USFWS Ecoregion classification system was designed by Robert G. Bailey working out of the Rocky Mountain Research Station in Colorado. In his paper, &quot;Identifying Ecoregion Boundaries&quot; found Here: &lt;a href=&quot;http://www.fs.fed.us/rm/ecoregions/docs/publications/identifying-ecoregion-boundaries.pdf&quot; rel=&quot;nofollow&quot;&gt;http://www.fs.fed.us/rm/ecoregions/docs/publications/identifying-ecoregion-boundaries.pdf&lt;/a&gt;  he outlines the rational used for identifying the boundaries, and the 20 different principals he used. They are: 1. The series of ecoregions should express the changing nature of the climate over large areas. 2. Boundaries of ecoregions coincide with certain climatic parameters, 3. , 4. , 5 - 20&lt;/p&gt;&#xA;" OwnerUserId="3317" LastEditorUserId="543" LastEditDate="2015-08-22T02:44:48.733" LastActivityDate="2015-08-22T02:44:48.733" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="5375" PostTypeId="2" ParentId="5346" CreationDate="2015-08-15T01:50:43.410" Score="3" Body="&lt;p&gt;There's a number of useful things mountains do and I'm not sure I'll get all of it, but one, mountains create slopes which directs rivers.   Without any mountains and height variation at all, earth would be 1 big ocean.   But if we ignore that and imagine that we have lighter granite plates (without mountains) and dense basalt below the oceans, then we could still have land masses (but no Hawaii), but rain, rivers and run-off would be significantly changed.   Mountains also play an important role in snow storage, leading to melt runoff and providing water for rivers into the spring and summer so you could see a sizable reduction in rivers and more drought.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also suspect, though I can't prove it, that mountains cool the air, they certainly pull water-vapor from the air and water-vapor is a powerful greenhouse gas though clouds can affect climate change both ways, the overall effect is likely a cooling one, so no mountains, Earth would probably be at least a degree or three warmer.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's also, perhaps a change to wind strength and direction, but I'm not smart enough to predict that.        I also agree with everything Michael said.    without mountains, plate tectonics would slowly rebuild them and erosion would gradually re-create natural slopes in land.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2015-08-15T01:50:43.410" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5376" PostTypeId="1" AcceptedAnswerId="5469" CreationDate="2015-08-15T04:18:13.230" Score="12" ViewCount="2024" Body="&lt;p&gt;Wikipedia comments &lt;a href=&quot;https://en.wikipedia.org/wiki/Greenhouse_and_icehouse_Earth#Modern_conditions&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; that &quot;Permanent ice is actually a rare phenomenon in the history of the Earth, occurring only during the 20% of the time that the planet is under an icehouse effect.&quot; A &quot;citation needed&quot; tag is attached to this remark.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For what percentage of the Earth's history has there been permanent (year-round) ice?&lt;/p&gt;&#xA;" OwnerUserId="3341" LastEditorUserId="11908" LastEditDate="2019-03-13T05:14:53.077" LastActivityDate="2019-03-13T05:14:53.077" Title="For what percentage of the earth's history has there been permanent ice?" Tags="|climate-change|earth-history|glaciology|ice|ice-age|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="5377" PostTypeId="1" AcceptedAnswerId="5385" CreationDate="2015-08-15T07:01:08.860" Score="9" ViewCount="210" Body="&lt;p&gt;I found this nice module &lt;a href=&quot;http://www.meted.ucar.edu/oceans/wavewatch3/navmenu.htm&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; on MetEd that gives an overview of the WAVEWATCH wave model. In it, in the Introduction section, it is mentioned that WAVEWATCH cannot model storm surge or tsunamis. Is this true of all 3rd generation models? Can source terms be added to the energy balance equation to model these phenomena?&lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorUserId="192" LastEditDate="2015-08-15T21:45:34.570" LastActivityDate="2015-08-18T01:56:11.403" Title="Why can't wave models model storm surge?" Tags="|models|waves|wave-modeling|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5380" PostTypeId="1" AcceptedAnswerId="5383" CreationDate="2015-08-15T15:26:03.070" Score="16" ViewCount="96068" Body="&lt;p&gt;Are clouds a solid, liquid, or gas?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have been looking online and they are often described ambiguously as a &quot;mass&quot;. For instance, &lt;a href=&quot;http://www.nasa.gov/audience/forstudents/5-8/features/what-are-clouds-58_prt.htm&quot;&gt;from NASA&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A cloud is a mass of water drops or ice crystals suspended in the&#xA;  atmosphere. Clouds form when water condenses in the sky. The&#xA;  condensation lets us see the water vapor. There are many different&#xA;  types of clouds. Clouds are an important part of Earth’s weather and&#xA;  climate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Since they describe it as a vapor, that makes me think it is indeed a gas. But condensation is by definition the change of state from a gas to a liquid. So that makes it sound like it could be a liquid, or contain liquid droplets rather than &quot;freely moving&quot; molecules that typically make up a gas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But at &lt;a href=&quot;http://www.sophisticatededge.com/are-clouds-a-gas-or-a-liquid.html&quot;&gt;another web site&lt;/a&gt;, which doesn't seem all that authoritative, it says that clouds are a solid, liquid, and gas simultaneously! &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A cloud is a liquid, a solid, and a gas.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That does seem intriguing. If I remember correctly, liquids are supposed to be incompressible, and clouds are likely compressible.&lt;/p&gt;&#xA;" OwnerUserId="3345" LastEditorUserId="3345" LastEditDate="2015-08-15T15:36:43.410" LastActivityDate="2018-09-15T18:02:01.857" Title="Are clouds a gas, liquid, and/or solid?" Tags="|clouds|gas|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5382" PostTypeId="2" ParentId="5380" CreationDate="2015-08-15T18:53:19.743" Score="8" Body="&lt;p&gt;A cloud isn't solid any more than a bunch of dust picked up by the wind is solid.   It's mostly air, but what you see is tiny suspended particles, so it's no more a liquid than a bunch of dust blowing in the wind is solid.  The entire cloud needs another definition because it's so diffuse.   Suspended very tiny drops of water or ice crystals is probably the best definition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If your next question is - how does ice and water not fall to the ground, the answer is that they do fall, but slowly enough that just a 1 or 2 MPH updraft is sufficient to keep a cloud aloft.   They fall quite slowly, like the speed of a feather, and it's not hard to keep a feather in the air with a little wind below it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, water vapor itself is transparent.   So clouds aren't water vapor, though they're obviously made primarily from condensed water vapor.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2015-08-15T18:53:19.743" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5383" PostTypeId="2" ParentId="5380" CreationDate="2015-08-15T19:50:16.643" Score="19" Body="&lt;p&gt;The cloud that you see is a mixture of solids and liquids.  The liquid is water and the solids are ice, &lt;a href=&quot;https://en.wikipedia.org/wiki/Cloud_condensation_nuclei&quot;&gt;cloud condensation nuclei&lt;/a&gt; and ice condensation nuclei (tiny particulates that water and ice condense on).  The invisible part of clouds that you cannot see is water vapor and dry air.  The majority of the cloud is just plain air in which the invisible water vapor is mixed with and the very tiny water drops and ice particles are suspended in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A cloud is a mixture of gas, liquid and solids.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-08-15T19:50:16.643" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="5384" PostTypeId="1" AcceptedAnswerId="5394" CreationDate="2015-08-15T20:08:47.370" Score="7" ViewCount="733" Body="&lt;p&gt;I recently developed a computer program that generates some petrophysical and elastic parameters from well logs such as water saturation and hydrocarbon saturation, bulk volume, irreducible water saturation, porosity, permeability, shear impedance, acoustic impedance, and poisson ratio. I would like to know which parameters to cross-plot. For example, can you use a cross-plot of depth versus acoustic impedance for detection of hydrocarbons? My analysis is aimed at reservoir characterization.  &lt;/p&gt;&#xA;" OwnerUserId="2950" LastEditorUserId="2950" LastEditDate="2015-08-18T11:21:26.787" LastActivityDate="2015-08-18T11:21:26.787" Title="petrophysical crossplots" Tags="|geophysics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5385" PostTypeId="2" ParentId="5377" CreationDate="2015-08-15T21:43:46.910" Score="13" Body="&lt;p&gt;Yes. Spectral wave models cannot model storm surge because the wave energy balance equation that they integrate does not describe the physical processes associated with storm surge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wave models solve the wave energy balance equation: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\dfrac{\partial E}{\partial t} &#xA;+ \dfrac{\partial (c_gE)}{\partial x}&#xA;+ \dfrac{\partial (\dot{k}E)}{\partial k}&#xA;+ \dfrac{\partial (\dot{\theta} E)}{\partial \theta}&#xA;= \rho_w g\sum S_i(x,k,\theta)&#xA;$$&#xA;where the terms on the LHS represent local change in time and advection of energy in geographical ($x$), wavenumber ($k$), and directional ($\theta$) space, respectively. The source terms $S_i$ on the RHS determine the growth and decay of wave energy due to wind input, wave dissipation, and non-linear wave-wave interactions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While mean water depth, wind forcing, and background Eulerian currents all affect the evolution of wave energy, the wave energy balance equation only solves for the statistical distribution of wave energy and its change in time. It does not provide information about the change of mean water level or Eulerian currents. The simplest equation set necessary to explicitly model surge are the single-layer (2-D) shallow water equations:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\dfrac{d\mathbf{u}}{dt}=-g\nabla\eta + \dfrac{1}{\rho_w} \dfrac{\partial \boldsymbol{\tau}}{\partial z} &#xA;$$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\dfrac{\partial \eta}{\partial t} = -\nabla \cdot (\mathbf{u}(H+\eta))&#xA;$$&#xA;where $\mathbf{u}$ is the Eulerian velocity and $\eta$ is the displacement from the mean water level $H$. $\nabla$ is the horizontal gradient operator. $\dfrac{\partial \boldsymbol{\tau}}{\partial z}$ is the vertical stress gradient that forces the flow - essentially the difference between surface and bottom stresses. The momentum equation describes how the flow velocity changes due to horizontal pressure gradient and surface forcing (stress). The mass continuity equation describes how the water elevation changes due to divergence of the flow. For spatial scales larger than 10 km or so, Earth's rotation becomes important and the RHS of the momentum equation must include the Coriolis acceleration.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another requirement for the model to simulate storm surge is to allow for wetting and drying. What this means is that the land cells, which are originally above mean water level, and thus not part of the model solution, can become wet once the water level reaches their height and &quot;submerges&quot; them. These grid cells then become part of the model solution. While this may sound obvious and physically intuitive, implementing a wetting-and-drying scheme in a model is a non-trivial challenge regarding software design.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the wave and surge models are coupled, the Eulerian velocity field $\mathbf{u}$ is mainly forced by wave dissipation, and less by wind directly. The surface elevation changes in response, and together with Eulerian velocity feeds back to the wave model. &lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2015-08-18T01:56:11.403" LastActivityDate="2015-08-18T01:56:11.403" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5386" PostTypeId="1" CreationDate="2015-08-16T20:00:20.690" Score="8" ViewCount="937" Body="&lt;p&gt;I need to regrid temperature dataset from 1 degree to 0.5 degree. In case we have data available for all grids falling in a square, as shown below, we can simply regrid it using bilinear/bicubic interpolation method in MATLAB.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NnfaS.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NnfaS.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But, the data grids which I have forms an irregular shape i.e., there are no values outsie the given grids as shown below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/e3yWM.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/e3yWM.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How to do regriding in this case ?&lt;/p&gt;&#xA;" OwnerUserId="5330" LastActivityDate="2017-03-12T20:24:28.717" Title="How to perform regridding (1.0d to 0.5d) using bilinear interpolation for an irregular area?" Tags="|meteorology|hydrology|climate-models|matlab|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="5393" PostTypeId="1" CreationDate="2015-08-17T15:12:23.003" Score="8" ViewCount="764" Body="&lt;p&gt;Water-worlds are becoming increasingly important in the exoplanet/astrobiology community. If plate tectonics create land masses, then can we say that a water-world (a planet with a global ocean and no land) does not have plate tectonics?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many astrobiologists say that plate tectonics may be a prerequisite for life to form on a given planet. Therefore, if the assumption that water-worlds do not have plate tectonics is true, then can we also say that these water-worlds cannot harbor life? &lt;/p&gt;&#xA;" OwnerUserId="3181" LastActivityDate="2015-08-18T13:11:37.100" Title="Do &quot;water-worlds&quot; not have plate tectonics?" Tags="|ocean|plate-tectonics|astrobiology|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5394" PostTypeId="2" ParentId="5384" CreationDate="2015-08-17T15:23:16.930" Score="7" Body="&lt;p&gt;&lt;strong&gt;Short answer: it depends.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The usual workflow is, very roughly, something like this:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Condition all your data. Compute any 'missing' data you need or want (e.g. porosity $\phi$, lithofacies, saturation $S_\mathrm{W}$, S-wave velocity $V_\mathrm{S}$).&lt;/li&gt;&#xA;&lt;li&gt;Inspect crossplots of relevant properties like velocity vs porosity, acoustic impedance vs elastic impedance (or maybe Poisson's ratio or ${V_\mathrm{P}}/{V_\mathrm{S}}$), and so on, colouring points by depth, $S_\mathrm{W}$ or lithofacies, say. Look for helpful discrimination. &lt;/li&gt;&#xA;&lt;li&gt;Use judgment, research, advice, or inspiration to decide on how to use the relationships you find... perhaps you are aiming for seismic inversion, or facies prediction, or log modeling, or something else.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Before doing much else, I recommend picking up Avseth et al. (Cambridge, 2005) (and/or perhaps  Dvorkin et al., Cambridge, 2014) and reading it from cover to cover. &lt;a href=&quot;http://www.agilegeoscience.com/blog/2014/7/18/six-books-about-seismic-analysis.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here are some short reviews and more details on these books.&lt;/a&gt; Alessandro Amato's &lt;a href=&quot;https://github.com/seg/tutorials&quot; rel=&quot;nofollow noreferrer&quot;&gt;two recent tutorials&lt;/a&gt; in SEG's &lt;em&gt;Leading Edge&lt;/em&gt; will help too, especially if you're using Python. If you're in MATLAB, a lot of the code for those books, which are both by the rock physics team at Stanford, &lt;a href=&quot;https://pangea.stanford.edu/researchgroups/srb/resources/books/quantitative-seismic-interpretation&quot; rel=&quot;nofollow noreferrer&quot;&gt;is available online&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are some nice $V_\mathrm{P}/V_\mathrm{S}$ &lt;em&gt;vs&lt;/em&gt; acoustic impedance $I_\mathrm{P}$ crossplots from &lt;a href=&quot;https://github.com/seg/tutorials/tree/master/1506_Seismic_petrophysics_2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Amato's second tutorial&lt;/a&gt; to inspire you:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YpGvh.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YpGvh.png&quot; alt=&quot;Vp/Vs vs P-wave impedance&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-08-17T15:23:16.930" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5397" PostTypeId="2" ParentId="5393" CreationDate="2015-08-17T19:31:15.010" Score="2" Body="&lt;p&gt;It would be impossible to answer this definitively, of course, but I would have to hypothesize that a water-world could harbor life, not intelligent, tool-using life, but basic stuff. Here's my logic: planet accretion leaves behind a lot of heat, even if it's not from radioactivity. Just the kinetic energy from accretion would take (probably) a billion years to dissipate. Even without plate tectonics, all that heat would have to vent via volcanic activity, and that energy could kick start life. If it hangs on long enough to develop photosynthesis (i.e. take advantage of solar energy), then even if the interior of the planet cools sufficiently to turn off plate tectonics, life would most like continue in one fashion or another. (Just my $0.02 worth...)&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2015-08-17T19:31:15.010" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5398" PostTypeId="1" CreationDate="2015-08-17T21:14:12.047" Score="7" ViewCount="488" Body="&lt;p&gt;Can anyone tell me the official or technical term for the effect of when extremely calm water appears when a ship turns sharply in a full circle? I realise it could be related to wakes, but is not a wake in the traditional sense.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Sj7a7.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Sj7a7.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has any research or modelling been conducted on this effect?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Richard&lt;/p&gt;&#xA;" OwnerUserId="3353" LastActivityDate="2016-11-01T19:39:58.717" Title="Ship turning causing calm water" Tags="|ocean|hydrology|ocean-models|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="5399" PostTypeId="2" ParentId="5393" CreationDate="2015-08-17T22:45:29.970" Score="3" Body="&lt;p&gt;I'm by no means an expert, but this Wikipedia link suggests that oceans make plate tectonics more likely, not less likely:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Plate_tectonics#Exoplanets&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Plate_tectonics#Exoplanets&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, a planet with twice the surface water as earth, covered by oceans might have almost no land but I think it's unlikely oceans would stop plate tectonics cause the heat still has to go somewhere, and it either circulates and pulls plates with it or it doesn't and it had the occasional volcano as the only means of releasing heat (Even Mars still has the very occasional volcano, and perhaps the Moon as well)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now if the oceans are 150 or 200 miles deep like Europa - I don't know what kind of effect that would have but just having oceans over the whole planet, I don't think that would likely prevent plate tectonics.  My guess is that mostly water worlds would still have plate tectonics most of the time, provided the planet itself is one that has plate tectonics.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2015-08-17T22:45:29.970" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5400" PostTypeId="1" CreationDate="2015-08-18T06:26:11.640" Score="7" ViewCount="2841" Body="&lt;p&gt;Is there an accurate way to count the amount of lightning happening in a thunderstorm? How is lightning measured? Is there a special unit for this?&lt;/p&gt;&#xA;" OwnerUserId="3040" LastEditorUserId="28050" LastEditDate="2015-10-29T16:01:46.553" LastActivityDate="2016-01-08T04:15:49.167" Title="How to count lightning in a thunderstorm?" Tags="|measurements|remote-sensing|lightning|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5401" PostTypeId="2" ParentId="5355" CreationDate="2015-08-18T11:11:21.770" Score="1" Body="&lt;p&gt;There are additional mathematical models for the profile of the wind speed above the ground. &#xA;For instance the power law: $u$ $=$ $bz^b$ (where $u$ is the speed of the ground at an height $z$ ;  $a$ and $b$ are numerical coefficients (usually it is assumed that $b$ $=$ $1/7$)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another expression for the wind speed profile is the exponential formula:&#xA;$u$ $=$ $a e^{-bz}$ where $u$, $z.a$ and $b$ are as previously defined (but here $b$ is not $1/7$)&lt;/p&gt;&#xA;" OwnerUserId="3319" LastEditorUserId="2470" LastEditDate="2015-08-18T11:47:20.897" LastActivityDate="2015-08-18T11:47:20.897" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5402" PostTypeId="2" ParentId="5393" CreationDate="2015-08-18T12:06:22.740" Score="0" Body="&lt;p&gt;Plate tectonics actually seperate land masses resulting into continental drifts, many geologic events can happen at plate boundaries, plates could be crushed into each other(convergent boundaries), a plate could be buried under(subduction zone), new continental crusts are formed(divergent plate boundaries) these geologic events are associated with heat, and heat could result to transformation of matter which could in some way may lead to life. So it is also possible that land subsidence submerged the continents in water. The mid oceanic ridge which is associated with several life forms and it is located at the bottom of the ocean.&lt;/p&gt;&#xA;" OwnerUserId="2950" LastActivityDate="2015-08-18T12:06:22.740" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5403" PostTypeId="2" ParentId="5393" CreationDate="2015-08-18T13:11:37.100" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;can we say that a water-world does not have plate tectonics?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No we can't. Take for example Earth, add in a lot of water to cover all of the continents and you get a water-world with active plate tectonics. The driver for plate tectonics is not whether water exist or not on the surface, but rather the internal heat a planet contains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or, the plates of plate tectonics could actually be water ice, as is hypothesised for Jupiter's moon Europa. You have to remember that currently our sample size is one. There is only one planet where we know for sure that there are active plate tectonics, and that is Earth. Ruling out plate tectonics on other planets just because we don't know how it will look like or how it will work is not correct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, water plays an important role in plate tectonics on Earth. Be it modifying the composition of the crust, changing the strength and ductility of the rocks, or some other process.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;then can we also say that these water-worlds cannot harbor life?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No. Again, our sample size is one. There is only one planet we know with life and that is our Earth. Who knows what may be out there? For starters, we don't even know what fired up life here on Earth in the first place. It could be volcanos or hydrothermal vents in the ocean around hot spots, which are (almost) independent of tectonic activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On a personal note, we've all seen how astronomy advanced from &quot;are there any other planets out there?&quot; to actually discovering hundreds of them. What was once the exception is now the rule. Who knows, life might actually exist on just about every solar system out there.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-08-18T13:11:37.100" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5404" PostTypeId="2" ParentId="5371" CreationDate="2015-08-18T13:33:07.653" Score="6" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;can he also say how accurate this estimations are?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Let's begin by saying that the crust is heterogeneous. There is no one &amp;quot;composition of the crust&amp;quot;. If you go to a place rich with limestones, then Ca and C are the most common elements (excluding O), if you go to a place rich with granites then Si and Al are the most common. Go to places with abundant basalt and you get lots of Mg. That means that the accuracy is irrelevant. If you have the average of an entire continent, there is no one rock or one area that has this composition. And if there is, it is by pure coincidence.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;what methods exist and were used to estimate this?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;One way to find an average is to know how much of each rock you got (which is easy if you have geological maps of everything) and what's the composition of each rock. However, there is a more clever way of doing it. You can sample sediments. Take major rivers that have huge areas in their drainage basin. These rivers transport the fragments of those rocks as sediments and deposit them in one place. All you have to do is to analyse those sediments. Surprisingly (or not), when you actually do this for rivers in Europe, America, Australia, etc, the composition of them turns out to be almost identical! So that's one way to derive an approximation.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;up to 50km deep&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You can't directly probe that deep. Our deepest drill hole was just over 10 km, and that was almost impossible (and extremely expensive to do). Fortunately, we have an indirect method of sampling rocks from 50 km and even deeper. Sometimes magma erupted from depth tears away pieces of rock from the walls of the conduit. This rock is then embedded in in the volcanic rock. Here's an example:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ODaiR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ODaiR.jpg&quot; alt=&quot;Xenolith&quot; /&gt;&lt;/a&gt;&#xA;&lt;sup&gt;Source: James St. John, &lt;a href=&quot;https://www.flickr.com/photos/jsjgeology/15614514062&quot; rel=&quot;nofollow noreferrer&quot;&gt;flickr&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;You have the black basalt and in it a rock that came from several tens of km below the surface (or more). By collecting a lot of those deep-seated rocks from volcanic rocks, we can get a good idea of what the lower crust and the upper mantle look like.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-08-18T13:33:07.653" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5405" PostTypeId="2" ParentId="3018" CreationDate="2015-08-18T18:26:50.413" Score="9" Body="&lt;p&gt;This question is intriguing. At the current rate of sea rise (about 3 mm per year), all of the Earth's dry land below sea level would be submerged in just a decade. There are an estimated 49 countries around the global with at least some real estate below -0- metres elevation, but the sum of all the potential volume (around 7,500 km^3) is insignificant compared to the volume of water generated by glacial and ice cap melt:  &quot;&lt;strong&gt;&lt;em&gt;A meter of sea level rise is a volume 50 times greater than all of the depressions that are below sea level in the world&lt;/em&gt;&lt;/strong&gt;&quot;, according to this link: &lt;a href=&quot;http://mountainmystery.com/2015/08/17/hiding-rising-seas-in-sunken-deserts/&quot;&gt;http://mountainmystery.com/2015/08/17/hiding-rising-seas-in-sunken-deserts/&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2487" LastActivityDate="2015-08-18T18:26:50.413" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5407" PostTypeId="1" AcceptedAnswerId="5408" CreationDate="2015-08-18T15:53:03.490" Score="14" ViewCount="1997" Body="&lt;p&gt;We can calculate the maximum possible height of the mountain on earth. &#xA;If the elastic limit of a typical rock is $3 \times 10^8\ \mathrm{N/m}$ and its mean density is $3 \times 10^3\ \mathrm{kg/m^3}$, then the breaking stress is $h\,\rho\,\mathrm{g}$, where $h$ is height, $\rho$ is the density of the rock, and $\mathrm{g}$ is the acceleration due to gravity. Then&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ h = \frac{\mathrm{elastic\ limit}}{\rho\,\mathrm{g}} $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Putting the values we get,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ h = 10^4\ \mathrm{m} $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;which is the maximum possible height. Now Mount Everest is within this limit, but &lt;a href=&quot;http://en.wikipedia.org/wiki/Mauna_Kea&quot; rel=&quot;noreferrer&quot;&gt;Mauna Kea&lt;/a&gt; is 10,210 m tall (measured from its oceanic base).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does this suggest that rock types at the base of this mountain are different?&#xA;Or does the presence of water have an effect?&lt;/p&gt;&#xA;" OwnerUserId="3355" OwnerDisplayName="Aneek" LastEditorUserId="28050" LastEditDate="2015-09-11T13:25:16.560" LastActivityDate="2020-09-25T11:17:56.553" Title="Why is Mauna Kea taller than the maximum height possible on Earth?" Tags="|mountains|geomorphology|" AnswerCount="3" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="5408" PostTypeId="2" ParentId="5407" CreationDate="2015-08-19T00:07:43.490" Score="22" Body="&lt;p&gt;Since over half of the height of Mauna Kea is under water, you need to consider the buoyancy effect. Instead of a density of &lt;span class=&quot;math-container&quot;&gt;$3 \times 10^3\ \mathrm{kg/m^3}$&lt;/span&gt;, the underwater portion has a net density of &lt;span class=&quot;math-container&quot;&gt;$2 \times 10^3\ \mathrm{kg/m^3}$&lt;/span&gt;. That will significantly increase the potential height of such a mountain. Add in all the other uncertainties (is Mauna Kea made of rock with &amp;quot;typical&amp;quot; elastic limit and density? is it even homogenous? are there dynamics involved? and &lt;a href=&quot;https://en.wikipedia.org/wiki/Love_of_Chair&quot; rel=&quot;nofollow noreferrer&quot;&gt;what about Naomi&lt;/a&gt;?) and there's no reason to see its height as a contradiction.&lt;/p&gt;&#xA;" OwnerUserId="534" OwnerDisplayName="Daniel Griscom" LastEditorUserId="534" LastEditDate="2020-09-25T11:17:56.553" LastActivityDate="2020-09-25T11:17:56.553" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="5409" PostTypeId="2" ParentId="5407" CreationDate="2015-08-20T02:39:00.620" Score="11" Body="&lt;p&gt;Your calculation of maximum height has a precision of one significant figure, 10000 meters. That is consistent with the height of Mauna Kea to the same precision of one significant figure. The difference, 210 meters, doesn't matter. Your question doesn't really make sense the way you have stated it.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You need to propose a model, and do a calculation, having more precision.  Your estimate of the maximum height needs more significant figures in it before you can say whether it is or is not consistent with observation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The stress below Oceanic Islands, such as the Hawaiian Islands, does exceed the strength of the crust and upper mantle. When volcanism ceases, oceanic islands sink below sea level.  &lt;/p&gt;&#xA;" OwnerUserId="178" LastActivityDate="2015-08-20T02:39:00.620" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5410" PostTypeId="1" CreationDate="2015-08-20T04:50:28.960" Score="6" ViewCount="2863" Body="&lt;p&gt;I have average annual rainfall values at few grids, as shown in below example;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lat: 25.5 26.5 33.5 34.5 35.5 36.5 41.5 42.5&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lon: 89.5 91.5 78.5 79.5 83.5 84.5 75.5 76.5&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rain: 110 120 122 135 114 116 145 120 110 110&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to plot it like a map, like this example&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ygDyf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ygDyf.jpg&quot; alt=&quot;Example plots&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each point will have a cell size of 1 degree, and there must be WGS 84 projection. How to plot them in MATLAB ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have around 4000 lat-lon values and these are not in sequence. Moreover the available Lat-Lon represent the irregular shape. &lt;/p&gt;&#xA;" OwnerUserId="5330" LastEditorUserId="2536" LastEditDate="2017-06-04T11:49:28.287" LastActivityDate="2017-06-04T11:49:28.287" Title="How to plot lat-lon-rainfall in MATLAB?" Tags="|meteorology|hydrology|matlab|visualization|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5411" PostTypeId="2" ParentId="5410" CreationDate="2015-08-20T05:31:33.373" Score="4" Body="&lt;p&gt;What kind of plot do you want? &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Lat = [25.5 26.5 33.5 34.5 35.5 36.5 41.5 42.5]; &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Lon = [89.5 91.5 78.5 79.5 83.5 84.5 75.5 76.5]; &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Rain = [110 120 122 135 114 116 145 120 110 110];&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;figure();&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;plot3(Lat,Lon,Rain,'o')&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;will give you a scatter plot with Lat being the x, Lon being the y, and rain being the z.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also note that because your vectors are different legnths, you cannot plot them. You must have vectors of the same lenght to plot (each point must correspond to another point on the axis).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other types of plots will require you to interpolate between the data points.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to plot it like in the comment below: &lt;strong&gt;pcolor&lt;/strong&gt; is your best choice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Say your Lat/Lon vectors have n points. Then to make an nxn grid, you can use the command&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;[X,Y] = meshgrid(Lat,Lon);&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This will give you the grid you want, as long as your Lat/Lon Vectors are spaced how you want. To get the 'color&quot; of the pcolor, you will need to have a nxn matrix of rain values: you will need to know what those are at each point. If you do not know those, then then you cannot plot it in map view unless you do some form of modeling or interpolation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have an irregular shape, I would not use matlab. I would use Visit or Paraview, and there are many guides online on how to use this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you must use matlab, I would create &quot;fake points&quot; to make the grid a regular shape, and give them false rain values (such as NaN). I would then edit the plot in a postprocessor (photoshop) so that Only the irregular shape appears. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The spacing of the grid does not matter as its specified via your vectors. &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="32" LastEditDate="2015-08-20T06:16:48.290" LastActivityDate="2015-08-20T06:16:48.290" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="5412" PostTypeId="2" ParentId="5410" CreationDate="2015-08-20T09:08:41.440" Score="4" Body="&lt;p&gt;There are two stages to what you want here.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;1. Converting point data to gridded data&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;First off, since you want to plot regular cells rather than the actual data that you have, you need to covert your point data to cells in some way. The best way to do this may depend on the data itself, but one way would be to interpolate, perhaps using something along the lines of,&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;SI = scatteredInterpolant(Lon, Lat, Rain, 'natural', 'linear')&#xA;% read up on and understand the last two parameters before choosing what to use&#xA;&#xA;%form the grid, with points 1 degree apart. &#xA;gx = min(Lon):1:max(Lon);&#xA;gy = min(Lat):1:max(Lat);&#xA;[ X, Y ] = meshgrid(gx, gy);&#xA;&#xA;%produce an actual grid of rain data&#xA;gridded = SI(X,Y);&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Alternatively, if your point data has a much higher resolution than the 1 degree grid, &lt;em&gt;and if it is regularly spaced&lt;/em&gt;, you could simply take the mean of the points that lie in each cell.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;2. Plotting that grid&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;A naive method, which might be helpful as a quick check that what comes before has worked, would be,&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;figure;&#xA;imagesc(flipud(gridded));&#xA;colorbar;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;However, that will treat lon and lat as x and y coordinates on a rectilinear grid. To plot with a projection (N.B., WGS84 is not a projection. You'll need to figure out exactly what you're after with more clarity), you ideally want the &lt;a href=&quot;https://uk.mathworks.com/products/mapping/&quot; rel=&quot;nofollow&quot;&gt;Mapping Toolbox&lt;/a&gt;. I'm not an expert on that, but it should make projected plots relatively straightfoward.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you don't have access to the Mapping Toolbox, then you could spend a lot of time faffing with coordinate transforms to do what you want... but my advice would be to spend the time learning the basics of a GIS package instead (&lt;a href=&quot;http://qgis.org&quot; rel=&quot;nofollow&quot;&gt;QGIS&lt;/a&gt; is free) and use that to do the job.&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2015-08-21T10:09:49.393" LastActivityDate="2015-08-21T10:09:49.393" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5413" PostTypeId="1" AcceptedAnswerId="5416" CreationDate="2015-08-20T13:37:16.517" Score="10" ViewCount="3267" Body="&lt;p&gt;Many of the celestial bodies in our solar system have well-established color schemes, at least in the minds of the public.  &lt;a href=&quot;http://mars.nasa.gov/images/mars-globe-valles-marineris-enhanced.jpg&quot;&gt;Mars&lt;/a&gt; is pale-red and black, &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/8/85/Venus_globe.jpg&quot;&gt;Venus&lt;/a&gt; (beneath the clouds) is generally shown in rich yellows and oranges, the &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/e/e1/FullMoon2010.jpg&quot;&gt;Moon&lt;/a&gt; ranges from dark to light gray, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And, of course, Earth is famously blue and green.  However, this is entirely because of the presence of large oceans and life.  We're not seeing Earth's geology represented in these colors, as we are with the other planets, we're seeing overlaid colors from other processes that don't apply to Mars, Venus, or the Moon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I'm wondering, if you stripped away life and the oceans, what color(s) would Earth be?  Based on types of rock, etc.  Would the seabed be a different color from the continents?  Would it be more uniform, or would it vary in color quite a bit from region to region?  Would it be a similar gray to the Moon, or would other chemical processes (like the rusting of Mars) give it a more unique palette?&lt;/p&gt;&#xA;" OwnerUserId="3357" LastActivityDate="2015-08-21T01:18:38.627" Title="What color(s) would Earth be without water or life?" Tags="|geology|planetary-science|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="5415" PostTypeId="1" AcceptedAnswerId="5418" CreationDate="2015-08-20T19:41:53.177" Score="4" ViewCount="753" Body="&lt;p&gt;I found the below sample on Monmouth Beach near Lyme Regis and I am unsure if it is a fossil or simply beef limestone. The beef limestone is from fibrous calcite layers within a shale (known as shales with beef). For those that are not familiar with the area the local geology consists of marine limestones, shales and mudstones of Jurassic age which are highly fossiliferous. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apologies for lack of a scale, it is 3 cm high and 2 cm wide, rounded like a tooth with a prominent rim around the base. Part of the back of the sample is flat as though it has been broken.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Front&quot; view&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fb90T.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fb90T.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Rear&quot; view&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Z9T7X.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Z9T7X.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for looking and please let me know if you would like any further information.&lt;/p&gt;&#xA;" OwnerUserId="3322" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T16:29:39.907" LastActivityDate="2019-08-29T16:29:39.907" Title="Fossil or Beef Limestone?" Tags="|geology|fossils|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5416" PostTypeId="2" ParentId="5413" CreationDate="2015-08-21T01:18:38.627" Score="9" Body="&lt;p&gt;That's actually an interesting question. Let's try to answer it, but first let's make a few assumption.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Oxygen on Earth is biogenic, so without life there would be no oxygen. However, let's assume that some magical process keeps the oxygen in the atmosphere.&lt;/li&gt;&#xA;&lt;li&gt;Oceans play an important role in plate tectonics, and without it it might change. Let's assume that plate tectonics keep on running regardless of the state of the oceans.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The majority of the Earth's surface is covered by oceanic crust. This crust is composed of basalt, an iron rich rock. This iron would rapidly oxidise and rust, giving a red tint (possibly Mars-like) to most of the Earth's surface. The mid ocean ridges will most likely be black, but it will get redder the farther you get away from there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The continental crust would like slightly different. Mountain ranges would appear grey, perhaps slightly pinkish - not too different from the highest peaks you see today. Most of the continental crust is composed of granite (&lt;em&gt;sensu lato&lt;/em&gt;), a grey-pinkish rocks. Because there's no life and no vegetation, that barren landscape you see high above the mountains would go all the way down to the base of them mountains. At the mountain's base, you would get deserts of quartz sand, slightly yellow. Think the sand dunes of the Sahara desert. This sand comes from the breakdown of the granites. Quartz, the most resistant mineral in the granite forms sand, I guess from the action of wind. The other minerals (mostly feldspar) break down to form all kinds of clays, aka dust.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to sum it up:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of the surface will be covered by dark red low lands, with high lands of sandy desert and Himalaya type mountain belts sticking out of them.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-08-21T01:18:38.627" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5417" PostTypeId="1" AcceptedAnswerId="5422" CreationDate="2015-08-21T10:00:31.763" Score="5" ViewCount="921" Body="&lt;p&gt;I am confused regarding the height above ground of this data set. &lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html&quot;&gt;http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have to reprocess this data set and need to know this piece of information.&lt;/p&gt;&#xA;" OwnerUserId="3061" LastActivityDate="2015-08-21T23:08:52.000" Title="What is the height above ground of NCEP/NCAR Reanalysis 1 variables?" Tags="|atmosphere|atmosphere-modelling|ncep|reanalysis|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5418" PostTypeId="2" ParentId="5415" CreationDate="2015-08-21T12:46:23.280" Score="4" Body="&lt;p&gt;Looks like cone from cone in cone limestone, a uncommon texture of limestone rock.&#xA;It is most likely not a fossil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have found very similar pieces here in Ohio that are Cambrian age.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An accurate description of cone in cone limestone can be found at:&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Cone-in-cone_structures&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Cone-in-cone_structures&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, I have found a number of fossil teeth from fish, sharks and mammals over the years and teeth are most often not the same color as the rock they are found in. &lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2015-08-21T12:46:23.280" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5420" PostTypeId="2" ParentId="5222" CreationDate="2015-08-21T13:06:29.163" Score="3" Body="&lt;p&gt;Any stone quartz rich and smooth not porous (no visible holes) like agates, quartzite or cherts are you best bet for getting a nice tumbled stone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A great book is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gems and Minerals of America: A Guide to Rock Collecting (1st Edition)&#xA;by Jay Ellis Ransom&#xA;Hardcover, 705 Pages, Published 1975&lt;/p&gt;&#xA;&#xA;&lt;p&gt;ISBN-10: 0-06-013512-3        / 0060135123&#xA;ISBN-13: 978-0-06-013512-6 / 9780060135126&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your local library might have a copy of it.&#xA;See to find on sale on Internet also: used ~$5.00&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.gettextbooks.com/isbn/9780060135126&quot; rel=&quot;nofollow&quot;&gt;http://www.gettextbooks.com/isbn/9780060135126&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;BTW, tumbling stones and rock collecting led me to a career as a geologist.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2015-08-21T13:06:29.163" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5421" PostTypeId="1" CreationDate="2015-08-21T18:33:34.277" Score="2" ViewCount="136" Body="&lt;p&gt;When reading about the projects that want to plant trees on the Sahel-Sahara border, for protection of the Sahel, I wonder what other possibilities there are.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Like, would it be possible to influence precipitation in the Sahara desert by enlarging the evaporation of seas and oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This question would combine a number of different sub-questions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First of all, would moistening the air help at all? When reading Wikipedia, it looks like the air in the Sahara is extremely dry, but there's also a lack of precipitation generation mechanism. Can rain be generated there if the air would be wetter?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly, when it rains in the Sahara, where does the rain come from? The main wind over the Sahara desert is an eastern to &lt;a href=&quot;https://en.wikipedia.org/wiki/Global_wind_patterns#/media/File:Map_prevailing_winds_on_earth.png&quot; rel=&quot;nofollow&quot;&gt;northeastern&lt;/a&gt; wind. So it comes from over the Asian mainland, and can't carry a lot of water.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Does it mainly come from different winds (like an occasional western wind)?&lt;/li&gt;&#xA;&lt;li&gt;Does it mainly come from evaporation of the red sea (though that has a small surface)&lt;/li&gt;&#xA;&lt;li&gt;Does it get carried all the way over Asia, so coming from the Pacific ocean?&lt;/li&gt;&#xA;&lt;li&gt;Anything other ideas?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Thirdly (this is more a physics question), is it feasible to alter the evaporation rate of a large water body (feasible as in comparison to the tree-planting project, so it can cost a few billions). The experiments I've found wrt the relation between water-surface temperature and evaporation seem to suggest an exponential relation. Which is at least nice, &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Water doesn't have a colour, so it doesn't extract a lot of energy from the solar rays (at least not at the surface, but the energy gets spread over the entire depth). If we could let an energy-absorbing coloured surface (a black surface) float just a few inches under water, it could heat the water surface and make it evaporate more.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By making it evaporate relatively near the coast (as opposed to evaporation in the middle of the ocean), the majority of rain will also have to fall on land &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When this technique could be applied to a decent portion of the Red Sea, the surface temperature could be enlarged sufficiently, which could let the Red Sea act as a big ocean, thus result in a wetter Sahara and Sahel.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This might of course be a very stupid idea (like the majority of fresh ideas).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I thought someone would have studied this thoroughly before me (at least before planing millions of trees), but I couldn't find a lot of info on it (not even on the basic questions like how strongly surface colour influences evaporation).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for reading through this, and trying to answer (a part of) it.&lt;/p&gt;&#xA;" OwnerUserId="3366" LastEditorUserId="111" LastEditDate="2015-08-21T18:36:31.080" LastActivityDate="2015-08-22T01:10:06.550" Title="Possibility to influence oceanic evaporation to protect Sahel/Sahara" Tags="|ocean|precipitation|desert|evaporation|" AnswerCount="1" CommentCount="1" ClosedDate="2015-08-24T14:21:17.067" ContentLicense="CC BY-SA 3.0" />
  <row Id="5422" PostTypeId="2" ParentId="5417" CreationDate="2015-08-21T23:03:01.977" Score="3" Body="&lt;p&gt;The height coordinate varies and is described for the various variables on the site you link.  For example:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Levels:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Surface or near the surface (.995 sigma level), or entire atmosphere (eatm)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Levels:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;17 Pressure levels (mb): 1000,925,850,700,600,500,400,300,250,200,150,100,70,50,30,20,10&#xA;  Some variables have less: omega (to 100mb) and Humidities (to 300mb).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;For the pressure levels coordinate the height above the ground is variable and dependent on atmospheric conditions.  The sigma levels are terrain following and flatten out with height and will vary with local topography. (see &lt;a href=&quot;http://www.met.tamu.edu/class/metr452/models/2001/vertres.html&quot; rel=&quot;nofollow&quot;&gt;this for more info&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can estimate height using the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hypsometric_equation&quot; rel=&quot;nofollow&quot;&gt;hypsometric equation&lt;/a&gt;, or use the geopotential field from the data to determine the height at specific grid locations (it will vary horizontally).  For processing, I would recommend using the geopotential data since it is available for each of the vertical coordinate possibilities in this dataset.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2015-08-21T23:08:52.000" LastActivityDate="2015-08-21T23:08:52.000" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5423" PostTypeId="2" ParentId="5421" CreationDate="2015-08-22T01:10:06.550" Score="2" Body="&lt;p&gt;Changing ocean evaporation would impact weather &amp;amp; climate &lt;strong&gt;globally&lt;/strong&gt;. While that may benefit some regions, it would be detrimental to other regions - robbing Peter to pay Paul.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the risks would be the effect on rainfall intensity, rainfall duration and the amount of rain falling in any location. It could have disastrous consequences for landslide prone regions or low lying areas prone to flooding.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Increased rainfall would result in accelerated soil leaching requiring soil nutrients to be replaced at a great rate to allow the continuation of farming and for forests to keep developing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The accelerated soil leaching would also have an impact on the oceans and marine life and land based life reliant on marine life. Additional phosphates would result in increased algal booms, particularly in estuarine waters. Excessive algal blooms can make such waters toxic to life than can only live in such waters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to accelerated soil leaching there will be associated soil run-off and silting of rivers, estuarine systems and coast outflow regions. For marine wildlife parks such as the Great Barrier Reef, that would have a devastating consequence and may lead to the destruction of all biodiversity with such reefs.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-08-22T01:10:06.550" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5424" PostTypeId="1" CreationDate="2015-08-23T15:59:24.693" Score="4" ViewCount="4292" Body="&lt;p&gt;Is 80 feet some sort of standard?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OiLvL.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OiLvL.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3373" LastActivityDate="2015-08-23T18:43:12.977" Title="Why does Google maps (in terrain mode) space thier topo lines 80 feet apart?" Tags="|topography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5425" PostTypeId="2" ParentId="5424" CreationDate="2015-08-23T18:43:12.977" Score="5" Body="&lt;p&gt;Based on USGS (Department of the Interior – United States Geological Survey) toopgraphic maps, where on a 7.5 min Quadrangle map, the contour interval is commonly 40 feet.  Larger maps 15 min to 1'-2' maps the interval is commonly 80-100 feet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All maps of the United States are commonly sourced from USGS based maps.  I am certain Google or Google's map provider is using USGS base maps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reference:&#xA;&lt;a href=&quot;http://geology.isu.edu/geostac/Field_Exercise/topomaps/vert_scale.htm&quot; rel=&quot;noreferrer&quot;&gt;http://geology.isu.edu/geostac/Field_Exercise/topomaps/vert_scale.htm&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2015-08-23T18:43:12.977" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5428" PostTypeId="1" CreationDate="2015-08-24T13:07:05.413" Score="1" ViewCount="56" Body="&lt;p&gt;I would like to know if knowing the history(elevation, temperature, etc) of montains has any application, different from killing curiosity of scientist. &lt;/p&gt;&#xA;" OwnerUserId="3376" LastEditorUserId="725" LastEditDate="2015-08-24T15:18:07.290" LastActivityDate="2015-08-24T15:18:07.290" Title="What is the value of calculating the elevation of mountains in the past? (paleoelevation)" Tags="|geology|paleogeography|orogeny|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5429" PostTypeId="2" ParentId="2914" CreationDate="2015-08-24T13:28:54.350" Score="3" Body="&lt;p&gt;Atmospheric pressure affects the bubbles that form in lava, and this effect can be used to estimate paleopressure at the time of emplacement of a lava flow. You might need some special conditions, but it is possible to make such a study. The technique is described in Sahagian et al. (2002).&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Sahagian, D. L., Proussevitch, A. A., &amp;amp; Carlson, W. D. (2002). Analysis of vesicular basalts and lava emplacement processes for application as a paleobarometer/paleoaltimeter. The Journal of Geology, 110(6), 671-685. [&lt;a href=&quot;http://www.jstor.org/stable/10.1086/342627&quot; rel=&quot;nofollow&quot;&gt;JSTOR link&lt;/a&gt;, &lt;a href=&quot;http://www.geo.mtu.edu/~raman/papers2/SahagianJG.pdf&quot; rel=&quot;nofollow&quot;&gt;free PDF link&lt;/a&gt;]&lt;/p&gt;&#xA;" OwnerUserId="3376" LastEditorUserId="94" LastEditDate="2015-08-26T05:16:59.253" LastActivityDate="2015-08-26T05:16:59.253" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5431" PostTypeId="2" ParentId="5428" CreationDate="2015-08-24T15:17:48.313" Score="2" Body="&lt;p&gt;Compared to some other fields in geology, this one actually has immediate practical implications.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By &quot;knowing the history of mountains&quot;, you can learn a lot about processes that involve erosion, weathering, seismicity, etc. This is important for risk management and mitigation. Landslides and rockfalls are a significant risk in some countries. There are many ways of studying these processes, one of them being the interpretation of past events: their causes and effects. This is also true for earthquakes (which as you know, move mountains up and down).&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-08-24T15:17:48.313" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5432" PostTypeId="1" CreationDate="2015-08-24T18:17:30.903" Score="5" ViewCount="58" Body="&lt;p&gt;I'm in the middle of writing my Master's thesis. I've analyzed Ocean Bottom Pressure (OBP) signals derived from observations by the GRACE satellites.These observations are able to reproduce sub-monthly OBP variability which was pre-GRACE not possible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I performed a DFT on the available data and found within the arctic region in winter a strong mode with a period length of 7-8 days.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of these sub-monthly OBP oscillations can be explained by atmospheric forcing or wind stress forcing and i was wondering if anyone knows any atmospheric oscillations with that period length and&#xA;in that region?&lt;/p&gt;&#xA;" OwnerUserId="1228" LastActivityDate="2015-08-24T18:17:30.903" Title="Weekly atmospheric or oceanic oscillation within Arctic region" Tags="|atmosphere|ocean|arctic|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="5434" PostTypeId="1" AcceptedAnswerId="5435" CreationDate="2015-08-25T14:27:07.943" Score="10" ViewCount="2671" Body="&lt;p&gt;The temperature of the troposphere decreases with altitude whereas it is opposite in the stratosphere and again fluctuates. Why is this so?&lt;/p&gt;&#xA;" OwnerUserId="3382" LastEditorUserId="192" LastEditDate="2015-08-25T15:26:54.683" LastActivityDate="2016-11-19T17:57:12.430" Title="Why are there different vertical gradients of temperature in different layers of the atmosphere?" Tags="|meteorology|atmosphere|temperature|troposphere|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5435" PostTypeId="2" ParentId="5434" CreationDate="2015-08-25T15:29:00.923" Score="9" Body="&lt;p&gt;The strong heat flux through the Earth's atmosphere, the presence of greenhouse gases, convection, and mixing conspire to push the troposphere away from thermodynamic equilibrium (isothermal atmosphere) and toward an adiabatic atmosphere. The natural drop in density with altitude means an adiabatic atmosphere is subject to a lapse rate, a nearly linear drop in temperature with increasing altitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Temperature rises with altitude in the stratosphere because this is where the ozone layer exists. The troposphere is primarily heated from below. In contrast, the stratosphere is primarily heated from within via absorption of ultraviolet sunlight by oxygen and ozone. A similar situation exists in the thermosphere, which is where the extreme ultraviolet and higher frequencies of sunlight are absorbed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The thermosphere is where atmospheric temperatures attain their highest values. (BTW, you wouldn't feel those extreme temperatures if you put on a spacesuit and took a spacewalk in the thermosphere. There's hardly anything there that high up.) In between the thermosphere and stratosphere is where atmospheric temperatures attain their lowest values. This is the mesosphere. Most of the extreme wavelength radiation has already been absorbed in higher layers. The mesosphere is too thin to support an oxygen-ozone cycle. All that's left is radiational cooling supported by a strong greenhouse effect, making the top of the mesosphere (the mesopause) extremely cold.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-08-25T15:29:00.923" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5437" PostTypeId="1" AcceptedAnswerId="5443" CreationDate="2015-08-26T09:35:37.977" Score="11" ViewCount="1859" Body="&lt;p&gt;I can't find any examples, has it just never happened before or is it impossible because of environmental factors?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="111" LastEditDate="2015-08-27T02:48:19.227" LastActivityDate="2015-08-27T02:48:19.227" Title="Can an Atlantic hurricane enter Mediterranean sea?" Tags="|meteorology|tropical-cyclone|atlantic|mediterranean|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5438" PostTypeId="2" ParentId="5437" CreationDate="2015-08-26T10:53:23.950" Score="2" Body="&lt;p&gt;Mediterranean tropical cyclones are extremely rare but do occur.&#xA;These are not Atlantic type hurricanes, they are typically not the product of a hot African tropical depression.  The most recent event was in November 7, 2014 &lt;a href=&quot;https://en.wikipedia.org/wiki/Mediterranean_tropical-like_cyclone&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for Atlantic basic hurricanes, it would seem nearly impossible.  The normal path of the storm leading it eastwards would be affected by the Gulf stream and North Atlantic Drift and would carry the storm north east.&lt;br&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/nQWJp.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nQWJp.gif&quot; alt=&quot;Gulf Stream&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Typical wind patterns along the subtropics also would carry a storm trending east to the North and East.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZWyPr.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZWyPr.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Mediterranean_tropical-like_cyclone&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Mediterranean_tropical-like_cyclone&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://www.weather.com/storms/hurricane/news/most-bizarre-hurricane-tropical-storm-cyclone-locations-20130829#/8&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.weather.com/storms/hurricane/news/most-bizarre-hurricane-tropical-storm-cyclone-locations-20130829#/8&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2854&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.wunderground.com/blog/JeffMasters/comment.html?entrynum=2854&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="2470" LastEditDate="2015-08-26T14:27:31.070" LastActivityDate="2015-08-26T14:27:31.070" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5439" PostTypeId="1" AcceptedAnswerId="5444" CreationDate="2015-08-26T13:00:03.460" Score="3" ViewCount="3175" Body="&lt;p&gt;Some reanalysis data sets provide different components of shortwave radiation (near infrared and visible) and longwave. They are referred as radiation or flux. Also there is no mention of &quot;direct&quot; radiation but only &quot;beam&quot;. Are these two considered the same? And does the word flux imply something in addition to radiation? Also what is the difference between the long wave and solar fluxes? Here are some examples taken from &lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.surfaceflux.html&quot; rel=&quot;nofollow&quot;&gt;the NCEP reanalysis site&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Visible beam downward solar flux&lt;/li&gt;&#xA;&lt;li&gt;Visible diffuse downward solar flux&lt;/li&gt;&#xA;&lt;li&gt;Upward longwave radiation flux&lt;/li&gt;&#xA;&lt;li&gt;Near IR beam downward solar flux&lt;/li&gt;&#xA;&lt;li&gt;Downward longwave radiation flux&lt;/li&gt;&#xA;&lt;li&gt;Downward solar radiation flux&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="3061" LastEditorUserId="64" LastEditDate="2015-08-27T01:57:17.883" LastActivityDate="2015-08-27T21:05:15.930" Title="shortwave and longwave radiation terminology, direct, beam, PAR, flux?" Tags="|atmospheric-radiation|reanalysis|radiative-transfer|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5440" PostTypeId="1" AcceptedAnswerId="5441" CreationDate="2015-08-26T13:52:50.843" Score="11" ViewCount="1265" Body="&lt;p&gt;It's well known that the $\mathrm{CO}_2$ levels around the world are increasing, leading to an increase in overall surface temperature, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I'm wondering, are these gases (or the effects from these gases) increasing the global atmospheric pressure to any great degree, or is the atmospheric composition changing without any major change to air pressure levels, compared to centuries or millennia ago?&lt;/p&gt;&#xA;" OwnerUserId="3357" LastEditorUserId="28050" LastEditDate="2015-09-01T14:05:59.413" LastActivityDate="2022-08-08T10:31:01.953" Title="Is increase in atmospheric $\mathrm{CO}_2$ concentration affecting Earth's atmospheric pressure?" Tags="|meteorology|atmosphere|climate|climate-change|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5441" PostTypeId="2" ParentId="5440" CreationDate="2015-08-26T14:15:51.560" Score="5" Body="&lt;p&gt;The air in the atmosphere is a fluid. The pressure exerted by a fluid on a horizontal surface can be calculated using the formula.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ P = \rho\,\mathrm{g}\, h $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$P$ is pressure&lt;/li&gt;&#xA;&lt;li&gt;$\rho$ is the density of the fluid&lt;/li&gt;&#xA;&lt;li&gt;$\mathrm{g}$ is the acceleration due to gravity&lt;/li&gt;&#xA;&lt;li&gt;$h$ is the height of the fluid&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The acceleration due to gravity is a constant and the height of atmosphere can be considered constant. That leaves only the density of the air in the  atmosphere as the only variable that will affect pressure on the surface of the Earth, in this situation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The amount of &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth&amp;#39;s_atmosphere&quot; rel=&quot;nofollow&quot;&gt;carbon dioxide in the atmosphere&lt;/a&gt; is around 400 parts per million — a very small proportion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Density_of_air&quot; rel=&quot;nofollow&quot;&gt;Air density&lt;/a&gt; varies according to temperature and pressure but is within the range of $1.146$ to $1.422\ \mathrm{kg/m}^3$. By comparison, water has a density of $1000\ \mathrm{kg/m}^3$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the quantity of carbon dioxide were to increase, even tenfold, it would have a negligible affect on the density of the air and thus a negligible affect on the atmospheric pressure on the surface of the Earth. Its effect on temperature is another matter.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;h3&gt;Edit&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Answer to the additional question: &lt;strong&gt;&lt;em&gt;Can you expound on what effect the increase in temperature will have on pressure?&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The relationship between pressure, temperature and volume for gases is given by the universal gas law which states,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ PV = m\, \mathrm{R}\, T $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$P$ is pressure&lt;/li&gt;&#xA;&lt;li&gt;$V$ is volume&lt;/li&gt;&#xA;&lt;li&gt;$m$ is mass&lt;/li&gt;&#xA;&lt;li&gt;$\mathrm{R}$ is the universal gas constant&lt;/li&gt;&#xA;&lt;li&gt;$T$ is temperature&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Rearranging the equation,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ P = \frac{m\mathrm{R}T}{V} $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When considering the affect of temperature on atmospheric pressure, $\mathrm{R}$ is already a constant and the mass and volume of the atmosphere can be considered to be constant because any changes due to increased $\ce{CO_2}$ will be exceedingly small and can be regarded as being negligible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consequently $m\mathrm{R}/V$ is a constant $\mathrm{k}$ and the equation becomes,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ P = \mathrm{k}T $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Kelvin temperature scale, used in the equation, is an extrapolation of the Celsius temperature scale, thus a rise in temperature of $1^\circ\mathrm{C}$ ($1\ \mathrm{K}$) will increase atmospheric pressure by $1\ \mathrm{pascal}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The average atmospheric pressure is $101\,325\ \mathrm{Pa}$. Assuming a very bad case scenario of a rise of $10^\circ\mathrm{C}$, the pressure would increase $10\ \mathrm{Pa}$, or $0.0099\%$, which is insignificant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Weather reports report atmospheric pressure in units of hectopascals ($\mathrm{hPa}$). A pressure of $101\,325\ \mathrm{Pa}$ is $1013.25\ \mathrm{hPa}$. A rise of $10\ \mathrm{Pa}$ is the same as $0.1\ \mathrm{hPa}$. &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_pressure#Local_variation&quot; rel=&quot;nofollow&quot;&gt;Atmospheric pressures vary between&lt;/a&gt; $890\ \mathrm{hPa}$ and $1090\ \mathrm{hPa}$.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="28050" LastEditDate="2015-09-01T14:23:40.790" LastActivityDate="2015-09-01T14:23:40.790" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5442" PostTypeId="2" ParentId="2263" CreationDate="2015-08-26T14:35:16.277" Score="6" Body="&lt;p&gt;It looks like a Gibbs oscillation, a basic feature of spectral analysis. In a spectral atmospheric model this means that near high orography artificial surface waves exist which may reflect in different variables. They are usually not considered to affect meteorology, however.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;onlinelibrary.wiley.com/doi/10.1029/2010JC006927/full&#xA;&lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0442%281994%29007%3C1169%3AROTGOI%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://journals.ametsoc.org/doi/abs/10.1175/1520-0442%281994%29007%3C1169%3AROTGOI%3E2.0.CO%3B2&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;This is from Bacmeister, Julio T. &quot;Weather Prediction Models.&quot; Climate Change Modeling Methodology. Springer New York, 2012. 89-114.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YhGTH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YhGTH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3385" LastEditorUserId="200" LastEditDate="2015-08-26T19:36:45.703" LastActivityDate="2015-08-26T19:36:45.703" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5443" PostTypeId="2" ParentId="5437" CreationDate="2015-08-26T16:46:15.873" Score="7" Body="&lt;p&gt;Apart from the fact that only a few tropical cyclones follow a more southerly route (a list bellow) after going around the North Atlantic, I think the main problem is that tropical cyclones would weaken significantly after landfall in the Iberian Peninsula. An example of this is &lt;a href=&quot;http://weather.unisys.com/hurricane/atlantic/2012/RAFAEL/track.gif&quot; rel=&quot;noreferrer&quot;&gt;Hurricane Raphael&lt;/a&gt; in 2012.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/N5Q1j.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/N5Q1j.gif&quot; alt=&quot;Source weather.unisys.com&quot;&gt;&lt;/a&gt; Source Weather.unisys.com.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is no &quot;easy&quot; path from the Atlantic into the Mediterranean for a system the size of a tropical cyclone. Other examples that followed a similar path but never made it the Mediterranean: &lt;a href=&quot;http://weather.unisys.com/hurricane/atlantic/2006/GORDON/track.gif&quot; rel=&quot;noreferrer&quot;&gt;Gordon (2006)&lt;/a&gt;, &lt;a href=&quot;http://weather.unisys.com/hurricane/atlantic/1998/JEANNE/track.gif&quot; rel=&quot;noreferrer&quot;&gt;Jeanne (1998)&lt;/a&gt;, &lt;a href=&quot;http://weather.unisys.com/hurricane/atlantic/1998/IVAN/track.gif&quot; rel=&quot;noreferrer&quot;&gt;Ivan (1998)&lt;/a&gt;, &lt;a href=&quot;http://weather.unisys.com/hurricane/atlantic/1992/FRANCES/track.gif&quot; rel=&quot;noreferrer&quot;&gt;Frances (1992)&lt;/a&gt;, &lt;a href=&quot;http://weather.unisys.com/hurricane/atlantic/1991/BOB/track.gif&quot; rel=&quot;noreferrer&quot;&gt;Bob (1991)&lt;/a&gt;, &lt;a href=&quot;http://weather.unisys.com/hurricane/atlantic/1987/ARLENE/track.gif&quot; rel=&quot;noreferrer&quot;&gt;Arlene (1987)&lt;/a&gt;, &lt;a href=&quot;http://weather.unisys.com/hurricane/atlantic/1967/CHLOE/track.gif&quot; rel=&quot;noreferrer&quot;&gt;Chloe (1967)&lt;/a&gt;, &lt;a href=&quot;http://weather.unisys.com/hurricane/atlantic/1965/CAROL/track.gif&quot; rel=&quot;noreferrer&quot;&gt;Carol (1965)&lt;/a&gt;, &lt;a href=&quot;http://weather.unisys.com/hurricane/atlantic/1953/DOLLY/track.gif&quot; rel=&quot;noreferrer&quot;&gt;Dolly (1953)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While the cyclones at the point of approaching the Iberian Peninsula are still tracked as tropical depressions, their characteristics are often similar to other extra-tropical storms.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2015-08-26T19:21:29.460" LastActivityDate="2015-08-26T19:21:29.460" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5444" PostTypeId="2" ParentId="5439" CreationDate="2015-08-27T02:17:26.340" Score="2" Body="&lt;p&gt;Beam radiation is direct radiation, e.g. photons that have not been scattered.  Diffuse radiation is indirect and has been scattered.  Examples of beam radiation from the sky would be from the sun directly to your eye.  Diffuse solar radiation would be the blue sky (scattered out of the direct beam by the atmosphere), clouds and anything you can see that is illuminated by the sun.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shortwave radiation refers to radiation of solar origin, which is primarily in the visible and shorter wavelengths.  Longwave refers to radiation of terrestrial origin, which is typically in the infrared and longer wavelengths (dependent on temperature) and is radiated by the earth, us, clouds, the atmosphere, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A flux is the &quot;rate of flow of a property per unit area&quot; and for radiation is generally expressed in watts per square meter, Wm$^{-2}$.  A watt is 1 Joule per second, so this is an energy flux, a or the mount of energy flowing through a 1 m$^{2}$ surface every second.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To apply this to your variables:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Visible beam downward solar flux&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the direct radiation in the visible spectrum from the sun expressed as a flow of energy.  This is generally given either at the top of atmosphere or at the surface.  For ToA, this would be the rate of energy through a 1 square meter patch just above the atmosphere.  For the surface, this would be the rate of energy into a 1 square meter area on the earths surface.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Visible diffuse downward solar flux&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a measure of radiation in the visible spectrum that isn't directly from the sun.  At the surface of the earth this flux would be the rate of energy flowing into a 1 square meter patch of earth from reflection of sunlight (scattering) and from the rest of the sky and clouds that isn't the direct path from the sun.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Upward longwave radiation flux&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the rate of energy flow from the sum of all terrestrial emission.  At the top of the atmosphere this would be the terrestrial energy escaping to space (per square meter).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Near IR beam downward solar flux&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the same as the visible beam downward solar flux except it is in the near IR band (infrared wavelengths longer but close to that of visible red) rather than in the visible spectrum. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Downward longwave radiation flux&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This flux is terrestrial emission sources that send energy downward toward the earth.  This energy would come from clouds, the atmosphere (greenhouse gasses), etc.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Downward solar radiation flux&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the total shortwave flux (visible + IR + UV, etc; beam and diffuse) downward through the top of atmosphere or at the surface.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2015-08-27T21:05:15.930" LastActivityDate="2015-08-27T21:05:15.930" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5446" PostTypeId="1" AcceptedAnswerId="6577" CreationDate="2015-08-27T10:17:17.013" Score="3" ViewCount="81" Body="&lt;p&gt;It is known that hurricane activity in Atlantic basin is less active than in East Pacific basin in seasons past, but for the 2005 and 2010 seasons, the Atlantic basin is busier than western Pacific basin.  However,I have never heard of the eastern Pacific basin having a busier season than the western Pacific basin, is that possible?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="64" LastEditDate="2015-08-27T13:23:42.483" LastActivityDate="2015-09-21T07:06:24.097" Title="Is it possible to have a busier tropical storm season in the eastern Pacific basin than in the western Pacific basin?" Tags="|meteorology|tropical-cyclone|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5448" PostTypeId="1" AcceptedAnswerId="5450" CreationDate="2015-08-28T02:21:53.870" Score="4" ViewCount="161" Body="&lt;p&gt;Can a device or radioactive tracer be inserted into a volcanic lava lake, sunk to the mantle, and study the flow of magma within the mantle?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="3256" LastEditDate="2015-08-29T01:15:18.500" LastActivityDate="2015-08-29T01:15:18.500" Title="Using current technology, is it possible to directly measure magma flow in the mantle?" Tags="|mantle|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5449" PostTypeId="2" ParentId="5440" CreationDate="2015-08-28T06:13:03.707" Score="1" Body="&lt;p&gt;Fred is right, any change is virtually nothing, certainly not noticeable to anything but very finely tuned instruments.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But lets look at the Chemical Process.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\ce{CH4}$ (mined from the ground) + $\ce{2O2 -&amp;gt; CO2 + 2 H2O}$.   The $\ce{H2O}$ while it enters the air as water vapor doesn't stay water vapor for any significant time so the Atmospheric scale tells us   $\ce{2 O2}$ to start (64 atomic weight), $\ce{CO2}$ out (44 atomic weight), so burning methane lightens the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, lets look at gasoline, which is a variety of hydrocarbons, but lets say Pentane is the most abundant one (not sure it is, but it might be) $\ce{C5H12}$, here we get the following:&#xA;$$\ce{C5H12 + 8 O2 -&amp;gt; 5CO2 + 6H2O}$$.   With this one we have 256 atomic weight to start and 220 atomic weight to finish.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the carbon to hydrogen ratio goes up, the mass of the gas after the fuel is burned goes up, but on average, because burning fossil fuel takes oxygen and makes water as well as $\ce{CO2}$, mostly you're losing mass in the atmosphere and gaining water - but in negligible amounts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are other, larger factors, which, I don't understand all that well, but oceanic absorption for example.   Oceans absorb atmosphere (less as they get warmer) so as the Earth warms the oceans will store less air and the atmosphere will gain in mass, a bit.   Similarly, warmer air holds more water vapor, so, while burning $\ce{CO2}$ takes a little bit of mass out of the atmosphere, the warming will have the reverse effect.   More water vapor will be in the air and less air will be in the water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A 3rd effect, photosynthesis for example takes in $\ce{CO2}$ and puts out $\ce{O2}$, so as plants grow, the mass of the atmosphere is reduced, but overall, plants are simply not growing fast enough to match our output of $\ce{CO2}$.  Not close.   But the respiration of animals and plants on the planet does play a role, but as near as I can figure, the mathematics of this is pretty simple.   Plants take in $\ce{CO2}$ and release $\ce{O2}$, animals, by eating plants, do the reverse, we breath in $\ce{O2}$ and exhale $\ce{CO2}$, so any net change due to animal life would probably register in total $\ce{CO2}$.  (I think).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So there's your answer.   The burning of the fuels makes the atmosphere a teeny tiny bit lighter but the warming of the atmosphere makes the atmosphere heavier and that's likely the trump ward.  A warmer earth has a heavier atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;About 0.25 of the mass of the atmosphere at any given time is water vapor &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Earth#Composition&quot; rel=&quot;nofollow&quot;&gt;(Source)&lt;/a&gt;, compared to about 400 PPM $\ce{CO2}$ or 0.04% by volume, but since $\ce{CO2}$ is about 50% heavier than the oxygen/nitrogen combination, about 0.06% by mass.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because $\ce{CO2}$ isn't just added, but oxygen is taken away in greater mass when burning fossil fuels  (44 to 64 with methane, 220 to 250 with pentane), it's tough to estimate but lets say about 15% of the mass of the increase in $\ce{CO2}$ is taken out of the atmosphere due to loss of $\ce{O2}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The increase in $\ce{CO2}$, from 280 PPM to 400 PPM, is 40%, so working out the math, 0.06% * 0.4* 0.15 = rough estimate 0.0036% of the mass of the atmosphere lost due to all our fossil fuel burning since the industrial revolution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But, just 1 degree of warming can increase the atmospheric $\ce{H2O}$ by 6%-7%, so if we figure about .8 degrees C of warming this century and we run the math on atmospheric water vapor   0.25% * 0.06 * 0.8 = 0.012, or over 3 times as much mass added to the atmosphere from warming as is lost in fuel burning.   And that doesn't take into account oceanic absorption, which as the oceans warm they hold less oxygen.   Similarly, as Tundra thaws, gas is released from the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The net change (while quite small) is likely a heavier atmosphere (about 1/100th of 1% (so far, and more to come), but that's 1/10th of a millibar.  A typical High to low pressure variation at sea level is about 30 millibars &lt;a href=&quot;http://www.theweatherprediction.com/habyhints2/410/&quot; rel=&quot;nofollow&quot;&gt;(Source)&lt;/a&gt;, so we are talking about an unnoticeable change. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My math is rough but I think that's the correct answer to your question.  You can't just weigh the $\ce{CO2}$ added, you have to also weigh the $\ce{O2}$ taken out and the bigger factors, atmospheric $\ce{H2O}$ and Oceanic absorption of atmospheric gas.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorDisplayName="user2872" LastEditDate="2015-08-29T15:20:58.777" LastActivityDate="2015-08-29T15:20:58.777" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5450" PostTypeId="2" ParentId="5448" CreationDate="2015-08-28T07:05:59.183" Score="3" Body="&lt;p&gt;There are many issues I have with your suggestion. How would you distinguish the radiation that your source would emit from other sources of radiation? Also how would you detect the radiation? Where would you place the radiation detector? A detector placed on the surface of the Earth would not detect any radiation from the Mantle because the Crust would absorb the radiation, due to its thickness.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any device that would be placed in a pool of magma would most likely be melted by the heat of the magma. If the shell of the device managed to survive, the electronics and sensors would be damaged to the point of being inoperable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a device were to survive the heat how would the device send signals to the surface of the Earth? Extreme ultra low frequency radio might work, but the source signal would need to be very strong and I don't envisage that being possible for a device dropped into a volcano.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Getting a device to sink into magma would require the device to have a density higher than that of the magma.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Drilling very deep holes to conduct a seismological survey of mantle magma is not possible given that the deepest hole ever drilled was the &lt;a href=&quot;https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole&quot; rel=&quot;nofollow&quot;&gt;Kola Superdeep Borehole&lt;/a&gt;, drilled by the Soviet Union during the 1970s and 1980s. Its final depth was 12 262 metres - one-third of the way through the Baltic continental crust. Drilling was terminated short of the 15 000 metre target due to the rock temperature being 180 degrees Celsius.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using &lt;a href=&quot;http://htthttp://www.sciencedirect.com/science/article/pii/S1474706506000465p://&quot; rel=&quot;nofollow&quot;&gt;electric potential variations&lt;/a&gt; within magma to study magma within the mantle would not be possible because the technique requires an antenna to be place in a drilled hole.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-08-28T07:05:59.183" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5452" PostTypeId="1" CreationDate="2015-08-28T10:13:52.733" Score="4" ViewCount="560" Body="&lt;p&gt;I watch the news and in the weather forecast it's always rainy in central Africa, especially in Addis Ababa. Why is that?  &lt;/p&gt;&#xA;" OwnerUserId="3398" LastEditorUserId="28050" LastEditDate="2015-08-31T00:13:41.403" LastActivityDate="2015-10-27T11:07:01.330" Title="Why is it always rainy in Addis Ababa?" Tags="|meteorology|weather-forecasting|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="5453" PostTypeId="1" CreationDate="2015-08-28T10:28:23.173" Score="5" ViewCount="809" Body="&lt;p&gt;I know this question have been asked very often, but I could not find a proper answer around StackExchange, so I thought this might be a good place to ask:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Have the landmasses of North and South America ever been part of the same continent?&lt;/p&gt;&#xA;" OwnerUserId="3399" LastEditorUserId="725" LastEditDate="2017-03-25T12:36:30.920" LastActivityDate="2017-03-25T12:36:30.920" Title="Have the landmasses of North and South America ever been part of the same continent?" Tags="|geology|plate-tectonics|earth-history|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5454" PostTypeId="1" AcceptedAnswerId="5455" CreationDate="2015-08-28T14:17:59.903" Score="22" ViewCount="2408" Body="&lt;p&gt;I have just been reading this article on &lt;a href=&quot;http://www.gizmodo.co.uk/2015/08/earth-is-probably-locked-into-at-least-three-feet-of-sea-level-rise/&quot;&gt;Gizmodo&lt;/a&gt; (known for its hard science I know), that talks about sea level rising by up to 3 feet(!).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the article and video, created from information from NASA it seems, it states that over the last 23 years sea level has risen in some areas and &lt;strong&gt;fallen&lt;/strong&gt; in others.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, whilst I am aware that the level of water will vary with tides, how can the general sea level fall in some areas whilst it rises in others? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Surely if I add 9999 million gallons of water to the oceans, then the water level of the whole world should raise by the same amount everywhere?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can the sea level rise in some places and fall in others?&lt;/p&gt;&#xA;" OwnerUserId="3400" LastEditorDisplayName="user12525" LastEditDate="2019-04-19T09:29:23.253" LastActivityDate="2019-04-19T09:29:23.253" Title="How can the world's sea level rise and fall simultaneously?" Tags="|oceanography|sea-level|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5455" PostTypeId="2" ParentId="5454" CreationDate="2015-08-28T16:10:15.187" Score="26" Body="&lt;p&gt;&lt;strong&gt;There are lots of controls on sea level, not just the volume of water in the world ocean. These controls operate on different time and spatial scales, and interact in nonlinear ways. As a result, both global ('absolute') sea level and local ('relative') sea level can rise in some places and fall in others.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, absolute sea-level &lt;a href=&quot;http://tidesandcurrents.noaa.gov/sltrends/sltrends.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;is currently rising&lt;/a&gt;, largely because polar ice is melting. But the rate of change is not the same everywhere, and indeed &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4728/why-is-relative-sea-level-falling-in-hudson-bay&quot;&gt;in some places sea-level is falling&lt;/a&gt;: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://tidesandcurrents.noaa.gov/sltrends/sltrends.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ItO7t.png&quot; alt=&quot;Rates of sea-level rise (NOAA)&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How can this be?&lt;/strong&gt; &lt;a href=&quot;https://en.wikipedia.org/wiki/Post-glacial_rebound&quot; rel=&quot;nofollow noreferrer&quot;&gt;Post-glacial isostatic rebound!&lt;/a&gt; Much of northern Canada was covered in a thick ice sheet in the last ice-age. This sheet was heavy enough to depress the lithosphere (the earth's crust)! Since the uppermost mantle ('asthenosphere') is plastic, it flowed out of the say, so to speak. The ice melted thousands of years ago, but the highly viscous asthenosphere is still flowing back, pushing the crust up as it does so. As the crust goes up, relative sea-level falls. &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;What about global sea-level?&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Aside: Some people think changes in global sea-level, sometimes called eustasy, are synchronous and evenly distributed (see early literature on &lt;a href=&quot;https://en.wikipedia.org/wiki/Sequence_stratigraphy&quot; rel=&quot;nofollow noreferrer&quot;&gt;sequence stratigraphy&lt;/a&gt;). But, as I hope this tiny introduction will illustrate, it's more complicated than that...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are lots of other mechanisms that affect sea-level, not just isostacy. Here's a list of &lt;strong&gt;L&lt;/strong&gt;ocal and &lt;strong&gt;G&lt;/strong&gt;lobal effects I made for my thesis (Hall, M, 1997, &lt;em&gt;Sequence stratigraphy and early diagensis: the Sobrarbe Formation, Ainsa Basin, Spain&lt;/em&gt;, Manchester); I've also &lt;a href=&quot;http://www.agilegeoscience.com/blog/2011/4/11/scales-of-sea-level-change.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;blogged about it&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hqb0B.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hqb0B.png&quot; alt=&quot;Things affecting sea-level&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some effects, like changes in the shape of &lt;a href=&quot;https://en.wikipedia.org/wiki/Geoid&quot; rel=&quot;nofollow noreferrer&quot;&gt;the geoid&lt;/a&gt; and hydro-isostacy, affect the deep ocean too — changing the amount of water that, say, the Pacific can hold. Like all the others, these vary in time and space, and have complex relationships to the other effects in that table... so it's quite hard to model all this!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/tagged/sea-level&quot;&gt;Footnote: There's lots more on Earth Science Stack exchange about sea-level.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-08-28T16:10:15.187" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="5456" PostTypeId="1" CreationDate="2015-08-28T17:18:26.770" Score="4" ViewCount="2221" Body="&lt;p&gt;What will happen if earth stops rotating as well revolving? Will we all be moving with its velocity? It should get displaced from its orbit and move in a tangential direction.&lt;/p&gt;&#xA;" OwnerUserId="3401" LastEditorUserId="192" LastEditDate="2015-08-28T17:45:33.990" LastActivityDate="2015-09-21T06:52:56.423" Title="What would happen if Earth suddenly stopped rotating and revolving at the same time?" Tags="|hypothetical|earth-rotation|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="5458" PostTypeId="2" ParentId="5448" CreationDate="2015-08-28T18:41:50.193" Score="3" Body="&lt;p&gt;Currently the most direct way of measuring mantle properties is using geophysics. For instance, magnetotellurics (MT) can be used to measure resitivity in the upper mantle at mid-ocean ridges:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QSKNE.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QSKNE.jpg&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;source: &lt;a href=&quot;http://www.nature.com/nature/journal/v495/n7442/fig_tab/nature11932_F2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.nature.com/nature/journal/v495/n7442/fig_tab/nature11932_F2.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;or near volcanoes:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wTuz1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wTuz1.png&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;source: &lt;a href=&quot;http://plutons.science.oregonstate.edu/research/magnetotellurics&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://plutons.science.oregonstate.edu/research/magnetotellurics&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you left the MT tools in the ground for a long time, you could record time-lapse resitivity measurements if you regularly grabbed the data. The change in the shape of the resitivity over time could potentially correlate to mantle flow. &lt;a href=&quot;http://geophysics.geoscienceworld.org/content/78/3/B121.abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;This paper&lt;/a&gt; describes a time-lapse MT method used to monitor changes in conductivity of a geothermal system over time. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Passive seismic data (sourced from earthquakes) may also be used to measure properties of the mantle, but a detailed model of mantle flow would be very difficult to build from seismic for many reasons. &lt;/p&gt;&#xA;" OwnerUserId="3256" LastActivityDate="2015-08-28T18:41:50.193" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5459" PostTypeId="1" CreationDate="2015-08-28T21:37:49.287" Score="8" ViewCount="1010" Body="&lt;p&gt;If the earth's mean sea level rises, I assume that requires humans to adjust current measurements of elevation? For example, Mt Everest would no longer be 8,848 metres above sea level. Is there a more stable universal way to measure elevation such as on other celestial objects?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that zero altitude on Mars is defined as a specific atmospheric pressure of 610.5 Pascals, about six millibars which is the triple point of water on Mars, where it can exist as gas, liquid or solid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The zero elevation point of the Moon is the average diameter since it has no atmosphere. So perhaps this is the most universal method to measure elevation?&lt;/p&gt;&#xA;" OwnerUserId="3406" LastEditorUserId="28050" LastEditDate="2015-08-29T12:35:44.940" LastActivityDate="2015-08-29T13:13:10.963" Title="What is the effect of rising sea level on measurements of elevation?" Tags="|sea-level|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5460" PostTypeId="2" ParentId="5459" CreationDate="2015-08-29T13:13:10.963" Score="9" Body="&lt;p&gt;&lt;strong&gt;Elevation can be measured against a tidal datum, in which case it is usually tied to some historic mean, or against a geodetic datum, which is statically defined.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Tidal datums&lt;/strong&gt;, of which there are &lt;a href=&quot;https://tidesandcurrents.noaa.gov/datum_options.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;many flavours&lt;/a&gt;, are only useful locally and, as you thought, they drift over time. Here's what NOAA says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Tidal datums are used as references to measure local water levels and should not be extended into areas having differing oceanographic characteristics without substantiating measurements. In order that they may be recovered when needed, such datums are referenced to fixed points known as bench marks. Tidal datums are also the basis for establishing privately owned land, state owned land, territorial sea, exclusive economic zone, and high seas boundaries.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;For large (continental or global) areas of interest, you need &lt;strong&gt;geodetic datums&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the UK, &lt;a href=&quot;http://www.ntslf.org/tgi/newlyn-tidal-observatory&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ordnance Datum Newlyn&lt;/a&gt; was defined in 1956 as the mean sea-level at Newlyn, Cornwall, between 1915 and 1921. In the US, the &lt;a href=&quot;https://en.wikipedia.org/wiki/North_American_Vertical_Datum_of_1988&quot; rel=&quot;nofollow noreferrer&quot;&gt;North American Vertical Datum of 1988&lt;/a&gt; prevails today (though &lt;a href=&quot;http://www.ngs.noaa.gov/datums/vertical/&quot; rel=&quot;nofollow noreferrer&quot;&gt;several others&lt;/a&gt; are in use). It was pegged to the local mean sea level height at Rimouski, Quebec, Canada.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two types of reference surface, the earth's equivalent of the celestial ones you mentioned in your question: the geoid, and ellipsoids. &lt;a href=&quot;https://en.wikipedia.org/wiki/Geoid&quot; rel=&quot;nofollow noreferrer&quot;&gt;The geoid&lt;/a&gt; is the surprisingly lumpy shape that the ocean surface would take in the absence of factors like tides. It can be measured with gravity anomalies, e.g. &lt;a href=&quot;http://www.csr.utexas.edu/grace/&quot; rel=&quot;nofollow noreferrer&quot;&gt;by GRACE&lt;/a&gt;. Since it's a natural surface, you could think of the geoid as the earth's absolute datum. Ellipsoids, on the other hand, are models of the geoid and, as mathematical surfaces, are smooth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pYNTj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pYNTj.jpg&quot; alt=&quot;Orthometric height from &quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As shown in the figure, GPS uses the &lt;a href=&quot;https://en.wikipedia.org/wiki/World_Geodetic_System#Main_parameters&quot; rel=&quot;nofollow noreferrer&quot;&gt;World Geodetic System of 1984&lt;/a&gt; for its measurements, so elevation is measured against its ellipsoid. So one must correct GPS elevations  to this &lt;a href=&quot;https://en.wikipedia.org/wiki/Orthometric_height&quot; rel=&quot;nofollow noreferrer&quot;&gt;orthometric height&lt;/a&gt; (height above the geoid).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to read more, &lt;a href=&quot;http://vdatum.noaa.gov/docs/datums.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this tutorial on datums&lt;/a&gt; from NOAA is pretty fantastic. And here's &lt;a href=&quot;http://mycoordinates.org/height-of-mount-everest/&quot; rel=&quot;nofollow noreferrer&quot;&gt;a nice piece on the height of Everest&lt;/a&gt;, with respect to various datums.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image: Judson L. Ahern, University of Oklahoma, via &lt;a href=&quot;http://www.fgdc.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Federal Geographic Data Committee&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-08-29T13:13:10.963" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5461" PostTypeId="2" ParentId="5456" CreationDate="2015-08-29T21:00:51.667" Score="2" Body="&lt;p&gt;Well, one side of the earth would heat up, while the other side would not. This would cause a very large thermal gradient, causing extreme wind speeds. Also, you would not have the Coriolis effect, destroying quasi-geostrophic theory.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2015-08-29T21:00:51.667" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5462" PostTypeId="1" CreationDate="2015-08-30T13:36:52.780" Score="4" ViewCount="145" Body="&lt;p&gt;Here's the base of my question: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/3001/was-volcanic-activity-more-prevalent-when-the-dinosaurs-roamed&quot;&gt;Was volcanic activity more prevalent when the dinosaurs roamed?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it true that during the time of the dinosaurs, both the oxygen requirements (by all living creatures on the planet) and the $CO_2$ released by volcanoes were higher than the same type of oxygen requirements today and the $CO_2$ pollution created by us and the currently active volcanoes?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to know if there's some simple argument against cars and factories being responsible for global warming (while methane production and deforestation are left behind) - that's what I believe in (for now).&lt;/p&gt;&#xA;" OwnerUserId="3415" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-09-20T20:56:19.873" Title="Difference between the oxygen/$CO_2$ ratio during the period of the dinosaurs and the present" Tags="|volcanology|earth-history|co2|oxygen|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5464" PostTypeId="1" CreationDate="2015-08-30T14:15:42.267" Score="1" ViewCount="859" Body="&lt;p&gt;This is Exercise 4.8.1 in &lt;em&gt;Introduction to Physical Hydrology&lt;/em&gt; by Martin Hendriks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The water level above flat terrain during an experiment with double ring infiltrometer is 20 mm. The saturated hydraulic conductivity of soil is 20 mm/h. The wetting front of soil suction is 60 mm. The initial soil moisture content is 20% and the effective porosity is 45%.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Calculate the infiltration rate and cumulative infiltration when wetting front is 20, 40, 80, 160, 320, 640 and 1280 mm below the soil surface. Why does the infiltration rate diminish with time?&lt;/p&gt;&#xA;" OwnerUserId="3416" LastEditorUserId="94" LastEditDate="2017-10-02T07:39:57.570" LastActivityDate="2017-10-02T07:39:57.570" Title="How to calculate the infiltration rate?" Tags="|geology|hydrology|homework|" AnswerCount="0" CommentCount="2" ClosedDate="2017-10-02T11:21:16.513" ContentLicense="CC BY-SA 3.0" />
  <row Id="5466" PostTypeId="1" CreationDate="2015-08-31T05:43:28.103" Score="1" ViewCount="96" Body="&lt;p&gt;Can we find crickets in Northern Wales? If no, what other insects found in Northern Wales make a chirping sound like that of crickets?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this isn't an appropriate question for this thread, please migrate it. &lt;/p&gt;&#xA;" OwnerUserId="3421" LastActivityDate="2015-08-31T11:29:15.027" Title="Crickets found in Wales?" Tags="|forest|" AnswerCount="1" CommentCount="3" ClosedDate="2015-08-31T12:06:36.743" ContentLicense="CC BY-SA 3.0" />
  <row Id="5467" PostTypeId="2" ParentId="5462" CreationDate="2015-08-31T05:52:12.440" Score="7" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is it true that during the time of the dinosaurs, both the oxygen&#xA;  requirements (by all living creatures on the planet) and the CO&lt;sub&gt;2&lt;/sub&gt;&#xA;  released by volcanoes were higher than the same type of oxygen&#xA;  requirements today and the CO&lt;sub&gt;2&lt;/sub&gt; pollution created by us and the&#xA;  currently active volcanoes?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm not quite sure what &quot;Oxygen requirements&quot; means.   It seems to me that atmospheric changes is a byproduct of life on earth more than a &quot;requirement&quot;.  There's other smaller factors, such as &#xA;volcanic activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think the best way to address this question is to start before the dinos, around 360 million years ago and the start of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Carboniferous&quot; rel=&quot;nofollow noreferrer&quot;&gt;Carboniferous Period&lt;/a&gt;&#xA;when oxygen increased to higher levels than it had ever been and CO&lt;sub&gt;2&lt;/sub&gt; levels fell significantly, perhaps as low as 300 PPM, though estimates vary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These lower levels of CO&lt;sub&gt;2&lt;/sub&gt; played a key role in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Karoo_Ice_Age&quot; rel=&quot;nofollow noreferrer&quot;&gt;Karoo Ice Age&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Something rather drastic happened around &lt;a href=&quot;https://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extinction_event&quot; rel=&quot;nofollow noreferrer&quot;&gt;251-252 million years ago&lt;/a&gt; but CO&lt;sub&gt;2&lt;/sub&gt; levels had started to rise before then, and the simple termite may have played a key role in the end of the Karoo ice age and rise in atmospheric CO&lt;sub&gt;2&lt;/sub&gt; .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the Dino's came about (230 million years ago), CO&lt;sub&gt;2&lt;/sub&gt; levels were too high to have glaciers.   Whether that was due to the massive mantle plume, or the termite or increased volcanic or some combination of all 3 is hard to say, but CO&lt;sub&gt;2&lt;/sub&gt; PPM has risen quite significantly by the time the Dinos came.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/37VPM.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/37VPM.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth&amp;#39;s_atmosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I recommend reading this part as it's more relevant to your question:  &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth&amp;#39;s_atmosphere#Measuring_ancient-Earth_carbon_dioxide_concentration&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth's_atmosphere#Measuring_ancient-Earth_carbon_dioxide_concentration&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I want to know if there's some simple argument against cars and&#xA;  factories being responsible for global warming (while methane&#xA;  production and deforestation are left behind) - that's what I believe&#xA;  in (for now).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There's really no good argument at all.   it's worth pointing out that while some people don't like the man made climate change theory and a handful of scientists continue to question it, it has stood up reasonably well to the tests, and no alternate theory has even come close.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the Koch brothers funded a study to prove the &quot;urban heat island&quot; effect, their study suggested the CO&lt;sub&gt;2&lt;/sub&gt; effect was even bigger than the IPCC's studies said it was.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are a number of factors that can effect climate.   The Earth's orbital changes, ocean current changes, sunspots, volcanism, deforestation, snow cover and albedo, cow farts, land location, mountain ranges and their effect on rain and atmospheric circulation, but none of those effects are playing a significant role in recent decades. CO&lt;sub&gt;2&lt;/sub&gt; is the only driver that makes any sense at all and it's quite clear that the cause of the rise in CO&lt;sub&gt;2&lt;/sub&gt; is the burning of fossil fuels.   &lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="725" LastEditDate="2016-09-17T00:58:38.097" LastActivityDate="2016-09-17T00:58:38.097" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5468" PostTypeId="2" ParentId="5466" CreationDate="2015-08-31T11:29:15.027" Score="3" Body="&lt;p&gt;There are crickets species living in Wales (&lt;a href=&quot;http://www.northwaleswildlifetrust.org.uk/wildlife/species-explorer/animal/invertebrates/grasshoppers-and-crickets&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reference&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Field Grasshopper&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Green Grasshopper&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Meadow Grasshopper&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Roesel's Bush-cricket&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Oak Bush-cricket&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Speckled Bush-cricket&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Mottled Grasshopper&lt;/p&gt;&#xA;&lt;p&gt;and even if a species is not common in this part of the UK it might be brought there e.g. as a secret passanger in a car.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="3289" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-08-31T11:29:15.027" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5469" PostTypeId="2" ParentId="5376" CreationDate="2015-09-01T12:53:35.003" Score="5" Body="&lt;p&gt;As has been abundantly said in the comments and on meta, there is no proper answer to this question in the current state of knowledge.&#xA;But indeed we can at least check if we can come up with a rough estimate (and thus try to see from where this 20% estimate comes from).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's first look at the main known glaciations:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;The Current one&lt;/strong&gt;: there is indeed a permanent ice sheet on the East Antarctic continent since, presumably, the early Oligocene (i. e. 35Ma, see e. g. &lt;strong&gt;DeConto &amp;amp; Pollard 2003&lt;/strong&gt;). There is considerable dispute on the exact timing of the onset of the EAIS but we're talking here about differences of &amp;lt;10Myrs, i. e. &amp;lt;0.25% of Earth history, so we can ignore for now this difference.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;The Karoo ice age&lt;/strong&gt;: the Carboniferous-Permian glaciation is thought to have spanned from the Mississipian (ca. 360Ma, &lt;strong&gt;Buggish et al. 2008&lt;/strong&gt;) to the Sakmarian (ca. 290Ma; &lt;strong&gt;Korte et al. 2008&lt;/strong&gt;), giving us a ca. 70Myr interval. However some studies have shown (e. g. &lt;strong&gt;Fielding et al. 2008&lt;/strong&gt;) that it was most probably an alternance of glacial and nonglacial climate rather than a continuous glaciation, meaning that permanent ice was probably present for way less than 70Myr.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;The Ordovician glaciation&lt;/strong&gt;: it is thought to have started between the late Katian and the early Hirnantian (ca. 445Ma) and to have ended either before the Silurian (see e. g. &lt;strong&gt;Finlay et al. 2010&lt;/strong&gt;) or at the beginning of the Silurian (ca. 440Ma; see e. g. &lt;strong&gt;Cooper &amp;amp; Sadler, 2012&lt;/strong&gt;). Hence an interval of 1 to 5 Myr. This one has been studied extensively as it is thought to be associated with one of the 5 major mass extinctions of the Phanerozoic (see the whole Sepkoski corpus).&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;The Cryogenian&lt;/strong&gt;: two glaciations are thought to have marked the Cryogenian (see e. g. &lt;strong&gt;Shields-Zhou et al. 2012&lt;/strong&gt;), the Sturtian (ca. 720 to 660Ma) and the Marinoan glaciations (ca. 650-635Ma), thus accounting for 75 Myr.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;The Huronian glaciation&lt;/strong&gt; lasting presumably from 2.45Ga to 2.22Ga (see a small review in &lt;strong&gt;Van Kranendonk, 2012&lt;/strong&gt;). The issue here being that the accuracy of paleoproterozoic event datation does not really allow to go much more into the details as this (both because of the extreme scarcity of the data and the relative low resolution of the dating techniques). Leaving us with a glaciation (or more probably a series of glaciations) that could have lasted up to 230Myr.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;To this, we can add various minor glaciations that are still highly debated such as the Late Devonian or the Middle to Late Jurassic (e. g. &lt;strong&gt;Dromart et al. 2003&lt;/strong&gt;). Whether of not they indeed occur, they hardly account for much of Earth History when aggregated so we can ignore them safely for the purpose of a rough estimate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This leads us to 35 + 70 + 5 + 75 + 230 = 415 Myr which equates to ~ 9 % of Earth History. Which is still far off 20% and I doubt that the minor glaciations put together account for 500Myr. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;&#xA;Buggish, W., Joachimski, M. M., Sevastopulo, G., Morrow, J. R., 2008. &lt;a href=&quot;http://dx.doi.org/10.1016/j.palaeo.2008.03.043&quot; rel=&quot;noreferrer&quot;&gt;Mississippian $\delta ^{13}C_{carb}$ and conodont apatite $\delta ^{18}O$ records — Their relation to the Late Palaeozoic Glaciation&lt;/a&gt;. Palaeogeography, Palaeoclimatology, Palaeoecology, 268: 273-292.&lt;br&gt;&#xA;Cooper, R. A., Sadler, P. M., &lt;a href=&quot;http://dx.doi.org/10.1016/B978-0-444-59425-9.00020-2&quot; rel=&quot;noreferrer&quot;&gt;The Ordovician Period&lt;/a&gt;. In Gradstein et al. 2012, The Geologic Time Scale 2012: 489-523.&lt;br&gt;&#xA;DeConto, R. M., Pollard, D. 2003. &lt;a href=&quot;http://www.nature.com/nature/journal/v421/n6920/abs/nature01290.html&quot; rel=&quot;noreferrer&quot;&gt;Rapid Cenozoic glaciation of Antarctica induced by declining atmospheric $CO_2$&lt;/a&gt;. Nature, 421: 245-249.&lt;br&gt;&#xA;Dromart, G., Garcia, J.P., Picard, S., Atrops, F., Lécuyer, C., Sheppard, S.M.F., 2003. &lt;a href=&quot;http://dx.doi.org/10.1016/S0012-821X(03)00287-5&quot; rel=&quot;noreferrer&quot;&gt;Ice age at the Middle–Late Jurassic transition?&lt;/a&gt; Earth and Planetary Science Letters, 213: 205-220.&lt;br&gt;&#xA;Fielding, C. R., Frank, T. D., Birgenheier, L. P., Rygel, M. C., Jones, A. T., Roberts, J., 2008. &lt;a href=&quot;http://dx.doi.org/10.1144/0016-76492007-036&quot; rel=&quot;noreferrer&quot;&gt;Stratigraphic imprint of the late Palaeozoic ice age in eastern Australia: A record of alternating glacial and nonglacial climate regime&lt;/a&gt;. Journal fo the Geological Society, 165: 129-140.&lt;br&gt;&#xA;Korte, C., Jones, P. J., Brand, U., Mertmann, D., Veizer, J. 2008. &lt;a href=&quot;http://dx.doi.org/10.1016/j.palaeo.2008.06.012&quot; rel=&quot;noreferrer&quot;&gt;Oxygen isotope values from high-latitudes: Clues for Permian sea-surface temperature gradients and Late Palaeozoic deglaciation.&lt;/a&gt; Palaeogeography, Palaeoclimatology, Palaeoecology, 269: 1-16.&lt;br&gt;&#xA;Shields-Zhou, G. A., Hill, A. C., Macgabhann, B. A., 2012. &lt;a href=&quot;http://dx.doi.org/10.1016/B978-0-444-59425-9.00017-2&quot; rel=&quot;noreferrer&quot;&gt;The Cryogenian Period&lt;/a&gt;. In Gradstein et al. 2012, The Geologic Time Scale 2012: 393-411.&lt;br&gt;&#xA;Van Kranendonk, M. J., 2012. &lt;a href=&quot;http://dx.doi.org/10.1016/B978-0-444-59425-9.00016-0&quot; rel=&quot;noreferrer&quot;&gt;A Chronostratigraphic Division of the Precambrian&lt;/a&gt;. In Gradstein et al. 2012, The Geologic Time Scale 2012: 299-392.&lt;br&gt;&#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2015-09-01T13:16:34.870" LastActivityDate="2015-09-01T13:16:34.870" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5470" PostTypeId="1" CreationDate="2015-09-01T17:13:08.920" Score="4" ViewCount="169" Body="&lt;p&gt;I'm considering a move/vacation to Seattle, and I'm concerned it may be dangerous due to the risk of an earthquake?&lt;/p&gt;&#xA;" OwnerUserId="3426" LastEditorUserId="32" LastEditDate="2015-09-01T22:15:22.463" LastActivityDate="2015-09-02T01:16:37.887" Title="Is it dangerous to live in Seattle due to the earthquakes?" Tags="|geophysics|earthquakes|seismic-hazards|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="5471" PostTypeId="2" ParentId="5470" CreationDate="2015-09-01T22:12:06.987" Score="1" Body="&lt;p&gt;Yes. Earthquakes are Dangerous&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No. Because big earthquakes happen so infrequently (~300 years in Seattle's case) that one shouldn't really worry about it. Engineers design buildings to withstand large earthquakes. Of course there is the possibility of failure, but generally the US is very good about their infrastructure. Seattle is not like Oklahoma, where they are completely unprepared for earthquakes. I lived in Los Angeles in 18 years, and while my time there was during the Northridge 1994 earthquake, most of the damage was to the buildings (which were insured) and not to the people. Still there is some risk, but I think the risk of driving in Seattle is probably riskier than living in Seattle for 50 years of earthquakes.&lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2015-09-01T22:12:06.987" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5473" PostTypeId="2" ParentId="5470" CreationDate="2015-09-02T01:16:37.887" Score="1" Body="&lt;p&gt;Earthquakes happen everywhere, even in places where some people think earthquakes are &quot;not supposed to happen&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tectonic boundaries, where crustal plates meet, such as the west coast of North America (San Andreas fault), the Himalayas, New Zealand and Japan are more prone to earthquakes than places in the middle of continental plates, such as Australia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But places far away from plate boundaries also experience earthquakes, sometimes large quakes of magnitudes 6 or 7, but such quakes in those sorts of locations are infrequent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ground stresses permeate the entire crust and there are faults of varying lengths and activities &lt;strong&gt;everywhere&lt;/strong&gt;. The ground stresses can cause faults, whether major or minor, to move, which causes earthquakes - even far away from major faults like the San Andreas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to your question, will Seattle experience an earthquake? Yes. When? That's unknown, because the timing, strength and exact location of earthquakes cannot be predicted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The best thing you can do, wherever you decide to live, is to avoid living in a dwelling that is built on soil that could liquify should an earthquake eventuate.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-09-02T01:16:37.887" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5475" PostTypeId="1" AcceptedAnswerId="5476" CreationDate="2015-09-02T17:02:57.433" Score="2" ViewCount="380" Body="&lt;p&gt;What are the main sources of $\ce{CO2}$ emission to the atmosphere? I know that the answer would probably be from the electricity sector and transportation but wouldn't most of the carbon dioxide produced from power plant be captured and stored by the CCS technology? Is it because not all the plants has the CCS technology to capture the $\ce{CO2}$? Or are there any scenario where CCS technology cannot be used e.g cars?&lt;/p&gt;&#xA;" OwnerUserId="3431" LastEditorUserId="111" LastEditDate="2015-09-02T18:23:13.510" LastActivityDate="2015-09-02T18:23:13.510" Title="Main sources of $\ce{CO2}$ emission to the atmosphere" Tags="|atmosphere|co2|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="5476" PostTypeId="2" ParentId="5475" CreationDate="2015-09-02T17:28:53.143" Score="5" Body="&lt;p&gt;These are from the EPA's site for 2013. The top is USA emissions and the bottom, global.  I guess that's the most recent year for which they have complete results. And you're right; electricity and transportation account for 58% of total CO&lt;sub&gt;2&lt;/sub&gt; emissions.&lt;br&gt;&lt;a href=&quot;https://i.stack.imgur.com/qObnq.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qObnq.jpg&quot; alt=&quot;Source: EPA, USA&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rXCC2.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rXCC2.jpg&quot; alt=&quot;EPA, Global&quot;&gt;&lt;/a&gt;&#xA;&lt;br&gt;The site is available &lt;a href=&quot;http://www.epa.gov/climatechange/ghgemissions/sources.html&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastEditorUserId="2959" LastEditDate="2015-09-02T17:43:14.750" LastActivityDate="2015-09-02T17:43:14.750" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="5477" PostTypeId="1" AcceptedAnswerId="5480" CreationDate="2015-09-03T15:44:22.943" Score="5" ViewCount="663" Body="&lt;p&gt;I have heard the claim by creationists that geologists date rocks by the fossils they contain and date fossils by the rocks in which they are found. This supposedly invalidates radiometric ages because they are a result of circular reasoning. Is this statement purely wrong, or is there some truth to it?&lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="28050" LastEditDate="2015-09-08T13:56:11.023" LastActivityDate="2015-09-08T13:56:11.023" Title="Age of fossils found in rocks" Tags="|geology|geochemistry|geochronology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="5478" PostTypeId="1" CreationDate="2015-09-03T17:59:15.527" Score="2" ViewCount="800" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Update:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Granted the question has been asked in different form; but the answer&#xA;  still escapes me. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;At one place I read that locations in question have low sea-surface&#xA;  temperature. At another place I read that due to land positions (or&#xA;  lack thereof) causes wind to not gather speed.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The answer mentioned in duplicate-suggestion-question are related to&#xA;  vertical wind shear. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Plus, my question is which of the following four options would you&#xA;  pick and why and why not others.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This was an MCQ in a recent exam, with only one option being correct:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Sea surface temperature are low.&lt;/li&gt;&#xA;&lt;li&gt;Inter-tropical Convergence Zone seldom occurs.&lt;/li&gt;&#xA;&lt;li&gt;Coriolis force is too weak.&lt;/li&gt;&#xA;&lt;li&gt;Absence of land in those regions.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I have doubts as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sea surface temp are a tad bit lower in those regions. Also, the ITCZ seldom crosses southwards. (Am I wrong?)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Coriolis force is good in 5 degrees to 30-40 degrees. (I think)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since, there can be only one option true, which one is true?&lt;/p&gt;&#xA;" OwnerUserId="3434" LastEditorUserId="3434" LastEditDate="2015-09-04T07:50:44.760" LastActivityDate="2015-09-04T07:50:44.760" Title="In the South Atlantic and South-Eastern Pacific regions in tropical latitudes, cyclone does not originate. What is the reason?" Tags="|temperature|tropical-cyclone|coriolis|cyclone|" AnswerCount="0" CommentCount="7" ClosedDate="2015-09-04T17:33:56.267" ContentLicense="CC BY-SA 3.0" />
  <row Id="5480" PostTypeId="2" ParentId="5477" CreationDate="2015-09-03T22:19:20.590" Score="11" Body="&lt;p&gt;Yes, there is some amount of circular reasoning in the statement: &quot;&lt;em&gt;geologist date rocks by the fossils they contain and date fossils by the rocks in which they are found&lt;/em&gt;&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, that statement does not fully describe how geologists date rocks or fossils. Dating rocks by fossils is a branch of geology called &quot;&lt;em&gt;biostratigraphy&lt;/em&gt;&quot;. This is a non-absolute and a relative method of dating. You know that one fossils is younger than another, so you can be sure that one rock is younger than another rock given that they have those fossils, respectively. How old are they exactly? Based on biostratigraphy alone, this is an unknown.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem is solved using &lt;em&gt;geochronology&lt;/em&gt;. Using radioactive decay to accurately and precisely date rocks. This is independent of fossils, but requires that the rock have to be dateable. This means that you need some kind of volcanic material (among other things) interbedded with the fossil bearing rocks. When you do that - you can be sure that a certain fossil formed at some exact point in time. Let's say 100 million years ago. Then you can use that knowledge to assign an age to rocks containing similar fossils where you do not have any rocks that you can date.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, new technological advances allow us to directly date fossils. One of the methods is using the Lu-Hf or U-Th-Pb systems on apatite - a mineral that forms teeth and bones. In cases where this method has been applied it showed that biostratigraphy actually works (unsurprisingly and to the dismay of creationists).&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-09-03T22:19:20.590" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="5481" PostTypeId="1" CreationDate="2015-09-03T23:29:17.570" Score="8" ViewCount="1807" Body="&lt;p&gt;In Grand Canyon there are two side streams that carry heavy carbonate loads and deposit travertine along their lengths. The Little Colorado and Havasu Creek both rise from springs a few miles above the river and are separated by over one hundred river miles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The white carbonate precipitate in each makes the light turquoise color of the water strikingly visible. What mineral in the water gives it the light turquoise color?&lt;/p&gt;&#xA;" OwnerUserId="3435" LastActivityDate="2017-04-26T18:48:05.160" Title="Why are the Little Colorado River and Havasu Creek blue?" Tags="|geochemistry|hydrology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6481" PostTypeId="2" ParentId="5477" CreationDate="2015-09-04T09:50:28.250" Score="7" Body="&lt;p&gt;In addition to what @Michael said, one can add that the claim that &quot;geologist date rocks by the fossils they contain and date fossils by the rocks in which they are found&quot; is misleading: are some rocks being dated using fossils? Yes. Are some fossils being dated by the rock they are contained in? Yes. But they are not the same fossils or the same rocks in both cases!  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;An example using marine micropaleontology (both because this is what I know best, but also because this is the discipline in which biostratigraphy is the most commonly used): some marine sections (not all) have unique sedimentary properties that allow the use of geochronological tools, or the use of magnetostratigraphy. But those sections are in practice a minority, so what we do is that we use the &quot;good&quot; sections as references: on those, we look at abundant microfossils having a clearly marked first and/or last occurrence, as a bio-datum. And then we use those datums on the other sections to &lt;em&gt;estimate&lt;/em&gt; their age. Eventually other microfossils are found on those sections and therefore their age are estimated this way. But those microfossils won't be used to date anything.&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2015-09-04T11:06:39.520" LastActivityDate="2015-09-04T11:06:39.520" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6483" PostTypeId="2" ParentId="5481" CreationDate="2015-09-04T15:38:19.123" Score="2" Body="&lt;p&gt;The color of the water is determined by depth and mineral composition. &lt;strong&gt;Calcium carbonate&lt;/strong&gt; is carried in the Little Colorado river water column and coats the river bottom. Calcium carbonate scatters white light (aka, looks white), so combined with water, which scatters blue light, a turquoise color is formed. When the water column is thin, white scattering of the calcium carbonate is more pronounced and the color of the water is lightened. In the deeper parts of the river, the color is a darker blue due to the smaller concentration of calcium carbonate (due to more volume of water) and the increased scattering of blue light through a thicker water column. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.crateinc.com/blog/2011/08/why-is-the-little-colorado-river-turquoise-blue/&quot; rel=&quot;nofollow&quot;&gt;This blog has a great explanation&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="3256" LastActivityDate="2015-09-04T15:38:19.123" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6484" PostTypeId="1" CreationDate="2015-09-04T16:21:49.980" Score="5" ViewCount="44" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4DDqQ.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4DDqQ.gif&quot; alt=&quot;http://ice-glaces.ec.gc.ca/prods/WIS130CT/20150903115200_WIS130CT_0008451788.gif&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fear with the polar bears is that the ice-free period in the bay is getting longer, right?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Did the consecutive polar vortex years from all this global weirding make the bay's winters colder? It was near-record cold as late as ~2/20/15 here but I'm 10-20° south of the bay, I don't know if the cooling effect of the wavy polar vortex extends that far north. It certainly makes the North Arctic warmer.&lt;/p&gt;&#xA;" OwnerUserId="4440" LastEditorUserId="4440" LastEditDate="2015-09-04T17:36:18.983" LastActivityDate="2015-09-04T17:36:18.983" Title="Why did Hudson Bay melt so late this year?" Tags="|meteorology|cryosphere|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6487" PostTypeId="1" CreationDate="2015-09-04T23:43:47.380" Score="1" ViewCount="319" Body="&lt;p&gt;Theoretically if in early years the earth was moving at an astronomically different pace (whether in orbit or rotation, whatever sounds better) wouldn't that alter the science of carbon dating? As I understand time relativity, If the speed at which the earth was moving changes, the elements and organisms there-in would experience time at a different rate.  Would we not expect that carbon would decay faster?  I know it's just theory but I'd like to know if this theory could be proven false. And is there any existing research that you are aware of that would support or debunk this theory?&lt;/p&gt;&#xA;" OwnerUserId="4442" LastActivityDate="2015-09-07T18:08:30.627" Title="Time relativity relating to Carbon dating?" Tags="|climate-change|paleontology|carbon|" AnswerCount="1" CommentCount="3" ClosedDate="2015-09-07T08:11:56.427" ContentLicense="CC BY-SA 3.0" />
  <row Id="6488" PostTypeId="1" CreationDate="2015-09-04T23:28:43.960" Score="11" ViewCount="137" Body="&lt;p&gt;Today, discourse on climate change seemingly tends to focus on earthly elements such as pollution and human activity. While I am certainly not well-read on climate change research, after inspiration from a physics teacher's example of a baseball bat's center of gravity, and from reading &lt;a href=&quot;https://space.stackexchange.com/questions/9365/do-the-planets-really-orbit-the-sun/&quot;&gt;this Stack Exchange post&lt;/a&gt;, I was curious about how the Sun's oscillation might play into our planet's entire climate activity. Have scientists even considered this information in determining the cause of climate change? Due to its elliptical orbit, Earth's distance from the sun changes, but wouldn't the Sun's oscillation affect what parameters this distance shall be over time?&lt;/p&gt;&#xA;" OwnerUserId="4443" OwnerDisplayName="user11553" LastEditorUserId="28050" LastEditDate="2015-09-05T08:57:47.343" LastActivityDate="2015-09-05T08:57:47.343" Title="Does the Sun's oscillation affect Earth's climate?" Tags="|climate|planetary-science|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6490" PostTypeId="2" ParentId="6488" CreationDate="2015-09-05T08:21:54.120" Score="7" Body="&lt;p&gt;I'll get you started at least, this is a bit too broad otherwise; I guess what you're describing are called &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot;&gt;Milanković (Milankovitch) cycles&lt;/a&gt;. Are climatologists aware of these? &lt;a href=&quot;https://www.ncdc.noaa.gov/paleo/milankovitch.html&quot;&gt;Yes&lt;/a&gt;, for a long time. Milanković published his first paper on the subject, &lt;em&gt;Theorie Mathematique des Phenomenes Thermiques produits par la Radiation Solaire&lt;/em&gt;, in 1920. As for Solar oscillations in general, even much longer periodicity of ~ 26 million years of the Sun's oscillation about the galactic plane &lt;a href=&quot;http://www.nature.com/nature/journal/v308/n5961/abs/308712a0.html&quot;&gt;has been considered before&lt;/a&gt; (in 1984). As we're aware of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_cycle&quot;&gt;11 year solar cycles&lt;/a&gt;, and have been integrated into climate models that climatologists work with, including collective effects of all of these manifesting in &lt;a href=&quot;http://cc.oulu.fi/~usoskin/personal/aa7704-07.pdf&quot;&gt;grand minima and maxima of solar activity&lt;/a&gt; (PDF).&lt;/p&gt;&#xA;" OwnerUserId="29" LastActivityDate="2015-09-05T08:21:54.120" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6491" PostTypeId="1" AcceptedAnswerId="6496" CreationDate="2015-09-06T22:40:37.733" Score="11" ViewCount="41465" Body="&lt;p&gt;I was just reading &lt;a href=&quot;https://en.wikipedia.org/wiki/1964_Atlantic_hurricane_season#Hurricane_Ethel&quot;&gt;this&lt;/a&gt; about how Hurricane Ethel could have merged with Hurricane Dora in 1964.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has such a merge ever happened before in history? If so, what was the result? Would storms become twice as powerful? Or would they disrupt and dissipate each other?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They don't have to be hurricanes or typhoons &lt;em&gt;per se&lt;/em&gt;, just large storms. I would think the low pressure regions of two storms would tend to attract each other if they were nearby, but it's apparently rare or unheard of because a quick google search showed nothing.&lt;/p&gt;&#xA;" OwnerUserId="2733" LastActivityDate="2020-08-22T14:14:32.690" Title="Have two hurricanes ever merged? And what was the result?" Tags="|meteorology|tropical-cyclone|" AnswerCount="2" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="6492" PostTypeId="1" AcceptedAnswerId="6594" CreationDate="2015-09-07T01:26:47.990" Score="8" ViewCount="534" Body="&lt;p&gt;The formation section in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Braided_river&quot; rel=&quot;noreferrer&quot;&gt;braided river&lt;/a&gt; Wikipedia says that very erodible soil causes braided rivers. Intuitively, a rising mountain range like the &lt;a href=&quot;https://en.wikipedia.org/wiki/Pamir_Mountains&quot; rel=&quot;noreferrer&quot;&gt;Pamirs&lt;/a&gt; would not be easily erodible. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Yarkant changes so abruptly, I'm curious what special geological feature is at these straight/meandering-to-braided junctions.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The critical factor that determines whether a stream will meander or braid is bank erodibility. A stream with cohesive banks that are resistant to erosion will form narrow, deep, meandering channels, whereas a stream with highly erodible banks will form wide, shallow channels, inhibiting helical flow and resulting in the formation of braided channels.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;h2&gt;Braid 1&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://goo.gl/maps/Vw1TT&quot; rel=&quot;noreferrer&quot;&gt;Here's&lt;/a&gt; near the edge of the Pamir range.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Q3Mcc.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Q3Mcc.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Braid 2&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Here's &lt;a href=&quot;https://goo.gl/maps/63lIX&quot; rel=&quot;noreferrer&quot;&gt;another braided section&lt;/a&gt; in the Pamirs, far upstream.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WnYXm.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WnYXm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;A source&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;There appears to be a glacier at &lt;a href=&quot;https://goo.gl/maps/76hsC&quot; rel=&quot;noreferrer&quot;&gt;a source of the Yarkant&lt;/a&gt; in &lt;a href=&quot;https://en.wikipedia.org/wiki/Central_Karakoram_National_Park&quot; rel=&quot;noreferrer&quot;&gt;Central Karakoram Park&lt;/a&gt;. If glaciers present/past explain braiding, why is it intermittent?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/z1o4h.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/z1o4h.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Minimal braiding in the Rockies&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Mountainous braided rivers seem rare/mild elsewhere, like &lt;a href=&quot;https://goo.gl/maps/AGqX0&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; in the Rockies in Missoula.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HK4Ap.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HK4Ap.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3296" LastEditorUserId="3296" LastEditDate="2015-09-08T10:57:33.943" LastActivityDate="2015-09-26T00:23:31.203" Title="Why is the Yarkant River braided in the Pamir mountains?" Tags="|mountains|rivers|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6493" PostTypeId="2" ParentId="6487" CreationDate="2015-09-07T02:25:53.207" Score="7" Body="&lt;p&gt;Earth &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_orbit&quot; rel=&quot;noreferrer&quot;&gt;travels along its orbit&lt;/a&gt; at about 30km/s. If you plug that number into a &lt;a href=&quot;http://keisan.casio.com/exec/system/1224059993&quot; rel=&quot;noreferrer&quot;&gt;time dilation calculator&lt;/a&gt;, you'll find that one second on Earth passes every 1.0000000050069 seconds in a Sun-centric reference frame.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Carbon-14 dating is good only to about 40,000 years into the past; Earth's time dilation would reduce that 40,000 years by a little under two hours, or far below the precision of the technique.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt; I'd like to address three more issues. First, the rotation of the Earth's surface only results in about 0.5km/s at the equator, and so is insignificant compared to the orbital velocity. Second, nothing has changed the Earth's orbit for many millions of years, probably for billions of years, so that would also have no effect on the dating.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Third, and more important, we're all traveling along on the Earth at (approximately) the same speed. So you, I, and a group of C-14 atoms in a fossil will all experience the same time dilation.&lt;/p&gt;&#xA;" OwnerUserId="534" LastEditorUserId="534" LastEditDate="2015-09-07T18:08:30.627" LastActivityDate="2015-09-07T18:08:30.627" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6495" PostTypeId="1" CreationDate="2015-09-07T04:46:02.243" Score="12" ViewCount="227" Body="&lt;p&gt;According to recent reports (e.g. &lt;a href=&quot;http://www.nature.com/news/pluto-s-massive-mountains-hint-at-geological-mysteries-1.17986&quot;&gt;in &lt;em&gt;Nature&lt;/em&gt;&lt;/a&gt;), Pluto is geologically active. It has some mechanism by which it has &quot;recycled&quot; its surface. I originally thought we had a similar case to Jupiter's moon Europa: tidal energy causes the moon to flex up and down and all that energy is then released as friction and heat, keeping the theoretical underwater ocean in Europa. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can't use this mechanism for Pluto, because it is locked with Charon, which is also geologically active. If the dwarf planet has some internal heat, its density is way too small for it to have lasted billions of years; in that case, Mars should still be geologically active. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone have any idea what keeps Pluto active or are scientists still trying to find out?&lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="28050" LastEditDate="2015-09-08T13:54:22.140" LastActivityDate="2020-08-20T11:32:44.867" Title="Mechanism for Pluto's young surface" Tags="|geophysics|geology|planetary-science|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6496" PostTypeId="2" ParentId="6491" CreationDate="2015-09-07T05:50:42.977" Score="12" Body="&lt;p&gt;Yes two hurricanes/tropical cyclones/typhoons can merge with each other and the effect is known as Fujiwhara effect- &lt;a href=&quot;https://en.wikipedia.org/wiki/Fujiwhara_effect&quot; rel=&quot;noreferrer&quot;&gt;Fujiwhara effect&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The National Weather Service defines the Fujiwhara effect as &quot;Binary Interaction where tropical cyclones within a certain distance(300-375 nautical miles depending on the size of the cyclones) of each other begin to rotate about a common midpoint&quot;. What really happens is that centers of both systems begin to orbit in a counter clockwise direction about a midpoint that is determined by the relative mass and cyclone intensity. Eventually the smaller cyclone may merge into the larger cyclone.&#xA;There are several examples of the Fujiwhara effect and one example would be  Hurricane Connie &lt;a href=&quot;https://en.wikipedia.org/wiki/Hurricane_Connie&quot; rel=&quot;noreferrer&quot;&gt;Hurricane Connie&lt;/a&gt; and Diane &lt;a href=&quot;https://en.wikipedia.org/wiki/Hurricane_Diane&quot; rel=&quot;noreferrer&quot;&gt;Hurricane Diane&lt;/a&gt; way back in 1955. Shimokawa et al &lt;a href=&quot;http://dil-opac.bosai.go.jp/publication/nied_natural_disaster/pdf/45/45-02E.pdf&quot; rel=&quot;noreferrer&quot;&gt;Fujiwhara Effect Types&lt;/a&gt; talk about the various kinds of interactions that can take place among various typhoons(Please note that the Fujiwhara effect is not restricted to two systems). The various kinds of interactions are &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Complete Merger&lt;/li&gt;&#xA;&lt;li&gt;Partial Merger&lt;/li&gt;&#xA;&lt;li&gt;Complete Straining Out&lt;/li&gt;&#xA;&lt;li&gt;Partial Straining Out&lt;/li&gt;&#xA;&lt;li&gt;Elastic Straining Out&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Complete straining and complete merger interactions lead to destruction of one of the vortices. Partial merger and partial straining lead to partial destruction of one vortex and elastic straining is an interaction in which both vortices survive with their initial circulation. Partial merger and partial straining out have received less attention in the literature on binary tropical cyclone interactions as the interactions are extremely complex. Prieto et al claim that during a partial merger repeated mass exchanges occur between vortices. As these are nonlinear effects a quantification is only possible by a direct numerical integration  and precise initial condition &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0493%282003%29131%3C2656%3AACOBTC%3E2.0.CO%3B2&quot; rel=&quot;noreferrer&quot;&gt;Binary TC Vortex Like Interactions&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The period of orbit maybe as small as one day or there are others such as Cyclone Kathy and Cyclone Marie &lt;a href=&quot;https://en.wikipedia.org/wiki/1964_Pacific_typhoon_season#Typhoon_Marie_.28Undang.29&quot; rel=&quot;noreferrer&quot;&gt;Kathy/Marie Fujiwhara&lt;/a&gt; orbited for a period of 5 days prior to merging into each other as pointed out by &lt;a href=&quot;http://twister.ou.edu/QJ/CD3-1990-1995/1993/v119n514/s5.pdf?origin=publication_detail&quot; rel=&quot;noreferrer&quot;&gt;Lander et al&lt;/a&gt;. If the period of orbit is longer then there is a greater probability of a merger.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Region wise binary cyclones are more common in the Western North Pacific than the North Atlantic as pointed by Dong et al &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0493%281983%29111%3C0945%3AOTRMOB%3E2.0.CO%3B2&quot; rel=&quot;noreferrer&quot;&gt;Relative Motion Of Binary Tropical Cyclones&lt;/a&gt;&#xA;Regarding the predictability of the track of binary cyclones Dong et al. state that prediction of steering forces of a single tropical cyclone are replete with numerical forecasting uncertainties and the problem is accentuated by the presence of another tropical cyclone in close proximity.&#xA;Those who followed the progress of Hurricane Sandy in late October 2012 (an instance of the Fujiwhara effect but in this case a tropical cyclone merged with an extra tropical storm) will remember the ECMWF model correctly predicted the landfall location. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2015-10-02T04:04:26.323" LastActivityDate="2015-10-02T04:04:26.323" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6497" PostTypeId="1" CreationDate="2015-09-07T09:53:11.793" Score="6" ViewCount="107" Body="&lt;p&gt;I know that some gases like CO&lt;sub&gt;2&lt;/sub&gt;, N&lt;sub&gt;2&lt;/sub&gt;O and CH&lt;sub&gt;4&lt;/sub&gt; absorb infra red radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the proportion or percentage of radiation absorbed by CO&lt;sub&gt;2&lt;/sub&gt; among all the gases?&lt;/p&gt;&#xA;" OwnerUserId="4450" LastEditorUserId="725" LastEditDate="2016-08-10T10:21:05.023" LastActivityDate="2016-08-10T10:21:05.023" Title="What is the ratio of infra-red light absorbed by green house gases?" Tags="|geochemistry|atmospheric-radiation|atmospheric-chemistry|gas|greenhouse-gases|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6498" PostTypeId="2" ParentId="6497" CreationDate="2015-09-07T10:42:44.503" Score="5" Body="&lt;p&gt;There is no simple relationship since it all depends on the frequency (IR spectral lines for most species of molecules are a mess). The most direct and precise way of calculation is through line-by-line calculation from a large spectrum database. The atmospheric column will be very different based on angle off normal, weather, and even time of day (water content has diurnal variability, mostly).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Surface temperature and surface properties also influence the distribution of emitted IR.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See also: &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_radiative_transfer_codes&quot; rel=&quot;noreferrer&quot;&gt;Atmospheric radiative transfer codes&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="269" LastEditorUserId="269" LastEditDate="2015-09-07T10:48:59.383" LastActivityDate="2015-09-07T10:48:59.383" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6499" PostTypeId="2" ParentId="5054" CreationDate="2015-09-07T12:27:57.913" Score="1" Body="&lt;p&gt;SWAT model has a pretty good technical and theoretical documentation on their website : &lt;a href=&quot;http://swat.tamu.edu/documentation/&quot; rel=&quot;nofollow&quot;&gt;http://swat.tamu.edu/documentation/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding the conceptual logic, SWAT is based on sub-watershed discretization. Inside these, it defines Hydrological Response Units (similar slope, land use and soil). Then, you simplify it on the basis of the HRU heterogeneity, you may chose between assigning to the sub-watersheds the response of the dominant HRU or define a multiple responses. At this step, SWAT knows which parameters to use in the hydrological processes you have selected and can run the simulation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would suggest that you read the introduction of the theoretical documentation and, assuming that surface runoff is a major contributor to your discharge, maybe the chapter 2.1 on surface runoff.  You need to understand the Curve Number Method wich is used to compute runoff volumes. If you want to decrease runoff speed, you may increase the manning coefficient (friction to flow) for both overland flow or channel flow. As it seems that you have a time of concentration greater than one day, you should also check the surface runoff lag parameter [SURLAG].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But as SWAT is a sophisticated model with a lot of parameters and sensitive to scale, discretization methods and input resolution, it is hard to know what's wrong with your simulation. It is quite normal that a uncalibrated model, even physically based, provides results far from the observed discharge. To calibrate a model, you must first identify the most sensitive parameters by running a sensitivity analysis. Then, as you know what parameters will have significant impact on the simulated discharge, you can run a calibration by varying them in a physically acceptable range.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this help,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;D.D.&lt;/p&gt;&#xA;" OwnerUserId="3363" LastActivityDate="2015-09-07T12:27:57.913" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6503" PostTypeId="1" AcceptedAnswerId="6504" CreationDate="2015-09-07T21:28:47.447" Score="10" ViewCount="2161" Body="&lt;p&gt;I have heard politicians claiming that volcanoes are the sole cause of global warming and using so called &quot;NASA data&quot; to show that the Earth is actually cooling instead of warming. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;While the nature of this site is for specific questions and not for political debate, we all know from &lt;a href=&quot;https://en.wikipedia.org/wiki/Year_Without_a_Summer&quot; rel=&quot;nofollow&quot;&gt;the Year Without a Summer&lt;/a&gt; that volcanic gases can impact the weather severely making it very cold or hot. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can a volcanic eruption, either a single or multiple explosions, be the sole cause of global warming at the planetary scale? Can volcanoes really change the climate so fast, relative to the geological timescale, that they produce the abnormal levels that we see today? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm aware of the year without summer, but that ended in a nanosecond, geologically speaking. &lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="725" LastEditDate="2016-08-10T10:15:20.620" LastActivityDate="2017-09-27T22:33:35.983" Title="Can volcanos change the climate?" Tags="|meteorology|climate|climate-change|volcanology|volcanic-hazard|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6504" PostTypeId="2" ParentId="6503" CreationDate="2015-09-07T23:11:41.483" Score="7" Body="&lt;p&gt;That the CO&lt;sub&gt;2&lt;/sub&gt; imbalance causing global warming is anthropogenic is accepted by 97% &lt;a href=&quot;https://www.skepticalscience.com/global-warming-scientific-consensus.htm&quot; rel=&quot;nofollow&quot;&gt;(source)&lt;/a&gt; of climatologists. This &lt;a href=&quot;https://www.skepticalscience.com/human-co2-smaller-than-natural-emissions.htm&quot; rel=&quot;nofollow&quot;&gt;site&lt;/a&gt; has this to say about human's effect on CO&lt;sub&gt;2&lt;/sub&gt; imbalance:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;But consider what happens when more CO&lt;sub&gt;2&lt;/sub&gt; is released from&#xA;  outside of the natural carbon cycle – by burning fossil fuels.&#xA;  Although our output of 29 gigatons of CO&lt;sub&gt;2&lt;/sub&gt; is tiny compared to the 750&#xA;  gigatons moving through the carbon cycle each year, it adds up because&#xA;  the land and ocean cannot absorb all of the extra CO&lt;sub&gt;2&lt;/sub&gt;. About 40% of&#xA;  this additional CO&lt;sub&gt;2&lt;/sub&gt; is absorbed. The rest remains in the atmosphere,&#xA;  and as a consequence, atmospheric CO&lt;sub&gt;2&lt;/sub&gt; is at its highest level in 15 to&#xA;  20 million years (Tripati 2009). (A natural change of 100ppm normally&#xA;  takes 5,000 to 20,000 years. The recent increase of 100ppm has taken&#xA;  just 120 years).&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Human CO&lt;sub&gt;2&lt;/sub&gt; emissions upset the natural balance of the carbon cycle.&#xA;  Man-made CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere has increased by a third since the&#xA;  pre-industrial era, creating an artificial forcing of global&#xA;  temperatures which is warming the planet. While fossil-fuel derived&#xA;  CO&lt;sub&gt;2&lt;/sub&gt; is a very small component of the global carbon cycle, the extra&#xA;  CO&lt;sub&gt;2&lt;/sub&gt; is cumulative because the natural carbon exchange cannot absorb&#xA;  all the additional CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Also, this &lt;a href=&quot;http://climate.nasa.gov/scientific-consensus/&quot; rel=&quot;nofollow&quot;&gt;site&lt;/a&gt; lists the acceptance of anthropogenic global warming from eighteen different scientific associations.&lt;br&gt;&lt;br&gt;I'm not sure politicians are the final authority for global warming.&lt;br&gt;&lt;br&gt;Edit: it has come to my attention that I did not actually answer the question posed in the title of this question, to wit: &quot;Can volcanos change the climate?&quot; I'll have to admit I did not. Taking the title and the body together as one topic I'll try to address the contribution volcanoes make to global warming.&lt;br&gt;&lt;br&gt;This &lt;a href=&quot;http://www.geology.sdsu.edu/how_volcanoes_work/climate_effects.html&quot; rel=&quot;nofollow&quot;&gt;site&lt;/a&gt; has this to say about the contribution of CO&lt;sub&gt;2&lt;/sub&gt; from volcanoes:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Volcanic eruptions can enhance global warming by adding CO&lt;sub&gt;2&lt;/sub&gt; to the&#xA;  atmosphere. However, a far greater amount of CO&lt;sub&gt;2&lt;/sub&gt; is contributed to the&#xA;  atmosphere by human activities each year than by volcanic eruptions.&#xA;  T.M.Gerlach (1991, American Geophysical Union) notes that human-made&#xA;  CO&lt;sub&gt;2&lt;/sub&gt; exceeds the estimated global release of CO&lt;sub&gt;2&lt;/sub&gt; from volcanoes by at&#xA;  least 150 times. The small amount of global warming caused by&#xA;  eruption-generated greenhouse gases is offset by the far greater&#xA;  amount of global cooling caused by eruption-generated particles in the&#xA;  stratosphere (the haze effect).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And this &lt;a href=&quot;http://hvo.wr.usgs.gov/volcanowatch/archive/2007/07_02_15.html&quot; rel=&quot;nofollow&quot;&gt;one&lt;/a&gt; has this:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Gas studies at volcanoes worldwide have helped&#xA;  volcanologists tally up a global volcanic CO&lt;sub&gt;2&lt;/sub&gt; budget in the same way&#xA;  that nations around the globe have cooperated to determine how much&#xA;  CO2 is released by human activity through the burning of fossil fuels.&#xA;  Our studies show that globally, volcanoes on land and under the sea&#xA;  release a total of about 200 million tonnes of CO&lt;sub&gt;2&lt;/sub&gt; annually. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;This seems like a huge amount of CO&lt;sub&gt;2&lt;/sub&gt; , but a visit to the U.S.&#xA;  Department of Energy's Carbon Dioxide Information Analysis Center&#xA;  (CDIAC) website (&lt;a href=&quot;http://cdiac.ornl.gov/&quot; rel=&quot;nofollow&quot;&gt;http://cdiac.ornl.gov/&lt;/a&gt;) helps anyone armed with a&#xA;  handheld calculator and a high school chemistry text put the volcanic&#xA;  CO2 tally into perspective. Because while 200 million tonnes of CO2 is&#xA;  large, the global fossil fuel CO&lt;sub&gt;2&lt;/sub&gt; emissions for 2003 tipped the scales&#xA;  at 26.8 billion tonnes. Thus, not only does volcanic CO&lt;sub&gt;2&lt;/sub&gt; not dwarf&#xA;  that of human activity, it actually comprises less than 1 percent of&#xA;  that value.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Certainly volcanoes can cause short-term climate effects. Pinatubo in 1992 reduced global temperatures by 0.5 to 0.6 degrees Celsius &lt;a href=&quot;http://pubs.usgs.gov/pinatubo/self/&quot; rel=&quot;nofollow&quot;&gt;(source)&lt;/a&gt;. IOW, it lowered temperatures, not raised them. So I think it's safe to say that humans contribute considerably more to warming than do volcanoes.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastEditorUserId="725" LastEditDate="2016-08-10T10:19:29.903" LastActivityDate="2016-08-10T10:19:29.903" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="6505" PostTypeId="2" ParentId="6503" CreationDate="2015-09-08T04:10:15.247" Score="11" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Can volcanos really change the climate so relatively (geological timescale speaking) fast, up to the abnormal levels that we are seeing today?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Even more so.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You wrote about the 1815 eruption of Mount Tambora. While that was an extremely large eruption in terms of written human history, it was rather tiny compared to the absolutely colossal volcanic events whose histories have been written in the rocks. Multiply the Tambora eruption by a factor of 10000 or more and you'll get things like the Deccan Traps and Siberian Traps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A number of geologists think that it was the formation of the Deccan Traps rather than the Chicxulub impact event that killed the dinosaurs. A much larger fraction think the combination of the two dealt a one-two punch that ended the reign of the dinosaurs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Siberian Traps are still deemed by many, if not most, geologist as the leading contender for the cause of the Permian–Triassic extinction event. This was by far the most severe extinction event ever, much greater in impact than the Cretaceous–Tertiary extinction event that killed the dinosaurs. The lava released by the Siberian Traps covered an area the size of Europe (or larger, depending on who you read). It may have triggered massive fires in coal deposits, significantly adding to the greenhouse gases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, what's happening to the Earth's atmosphere now is not a result of volcanic activity. It's us. (That of course is assuming that the massive amounts of hot air that comes out of the mouths of politicians is not classified as volcanic.)&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2015-09-08T05:58:55.960" LastActivityDate="2015-09-08T05:58:55.960" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="6507" PostTypeId="1" CreationDate="2015-09-08T08:53:26.977" Score="8" ViewCount="145" Body="&lt;p&gt;All the formulas presented in the relevant technical literature refer to channels of rectangular cross section — the formulas assume a constant depth of flow right across the channel section.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I need to calculate the bed load in a channel of roughly triangular cross section. I do not think that calculating the bed load discharge with the average depth of flow is appropriate or theoretically justified, so I am looking for a special hydraulic analysis of the situation which may be applied to channels of triangular or trapezoidal cross section.&lt;/p&gt;&#xA;" OwnerUserId="3319" LastEditorUserId="28050" LastEditDate="2015-09-08T13:46:33.567" LastActivityDate="2018-03-14T11:08:55.323" Title="How to model bed load transport in channels of non-rectangular cross sections" Tags="|models|sedimentology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6509" PostTypeId="1" AcceptedAnswerId="6563" CreationDate="2015-09-08T19:24:22.287" Score="3" ViewCount="49" Body="&lt;p&gt;Accept my apologies for weak formulation of my question. I do not have any background in environmental sciences, but since recently a lot of coverage in the media has been devoted to future droughts in Iran and their socio-economical effects, I got curious enough to investigate the depth of the matter. My main question is that when a drought in a region plagues an agriculture-based economy, what are the options for a fast and flexible transition in the economy of that region? By transition, I mainly mean providing a new source of income for the individuals, such that the drought does not translate to unemployment and/or relocation of people. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I assume that this has been studied, and maybe best practices already exist. However, since I'm not even remotely familiar with environment science, I don't even know which keywords I should search for. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a dedicated field of research investigating this question? Is there a definitive book on this topic? It looks like a question on which a UN-related organization has already published some reports. If I want to find these hypothetical reports, what should I exactly search for? &lt;/p&gt;&#xA;" OwnerUserId="4457" LastActivityDate="2015-10-19T10:31:09.617" Title="How should I start studying about 'successful transitions in post-drought economies'?" Tags="|economic-geology|drought|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6510" PostTypeId="2" ParentId="3091" CreationDate="2015-09-09T08:29:11.240" Score="3" Body="&lt;p&gt;A recent study about rogue events (including waves) is published in the Physical Review Letters paper &lt;a href=&quot;http://journals.aps.org/prl/abstract/10.1103/PhysRevLett.114.213901&quot; rel=&quot;nofollow&quot;&gt;Predictability of Rogue Events&lt;/a&gt; (Birkholz et al. 2015) &lt;em&gt;Abstract only&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main findings are that by using nonlinear time series analysis, and combining rogue wave data recorded from the Draupner platform (&lt;a href=&quot;https://en.wikipedia.org/wiki/Draupner_wave&quot; rel=&quot;nofollow&quot;&gt;Draupner Wave&lt;/a&gt;, with time series from two optical systems, the researchers have found evidence that suggests that despite the turbulence involved, a small time warning could be given as their research suggests that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;rogue events do not necessarily appear without a warning, but are often preceded by a short phase of relative order.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This study hints at a very short warning could be provided, as in the New Scientist summary article &lt;a href=&quot;https://www.newscientist.com/article/dn27673-rogue-wave-ahoy-new-technique-can-predict-surprise-sea-threat/&quot; rel=&quot;nofollow&quot;&gt;Rogue wave ahoy! New technique can predict surprise sea threat&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;means rogue ocean waves are deterministic and have a small amount of predictability. This is because rogue ocean waves arise from turbulence, which is difficult to predict, he says, but not random at its core, he says. In the best case scenario such waves might be predicted 10 to 20 seconds before impact.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user2872" LastEditorDisplayName="user2872" LastEditDate="2015-09-09T08:34:58.763" LastActivityDate="2015-09-09T08:34:58.763" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6511" PostTypeId="1" CreationDate="2015-09-09T14:00:48.797" Score="8" ViewCount="466" Body="&lt;p&gt;I'm trying to build an air pollution model. So far I have built one for point sources. Now I'm looking at monitoring air pollution with satellite images, based on the idea that every basic pollutant somehow reacts with EM. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is a sufficient number of sampling points?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, I know, it depends on the size of area. But right now I have only 10 sampling points (monitoring stations) for a Landsat image (a really big area). The Landsat image covers part of central Slovakia, ca. 23,000 km&lt;sup&gt;2&lt;/sup&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm afraid I can't complete my master's thesis without adding my own measurements, but that's difficult to implement. Maybe a possible way is to add data from measuring stations that are located in neighboring countries. But that would still only make 28 sampling points..&lt;/p&gt;&#xA;" OwnerUserId="4463" LastEditorUserId="4463" LastEditDate="2015-09-12T11:07:28.810" LastActivityDate="2015-09-12T11:07:28.810" Title="Monitoring air pollution with Landsat satellite data" Tags="|models|environmental-protection|atmospheric-radiation|air-pollution|satellites|" AnswerCount="0" CommentCount="14" ContentLicense="CC BY-SA 3.0" />
  <row Id="6512" PostTypeId="1" AcceptedAnswerId="6513" CreationDate="2015-09-09T18:40:32.150" Score="12" ViewCount="459" Body="&lt;p&gt;Clouds of the same type have such a consistent altitude, it appears as if they're floating on an invisible layer.  Is this true?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Put another way, is there a significant change in air composition at the point  where clouds float/form, or is that altitude determined primarily by air pressure?&lt;/p&gt;&#xA;" OwnerUserId="4465" LastEditorUserId="64" LastEditDate="2015-09-09T19:32:19.147" LastActivityDate="2015-09-09T19:32:19.147" Title="Do clouds float on anything?" Tags="|meteorology|clouds|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6513" PostTypeId="2" ParentId="6512" CreationDate="2015-09-09T19:32:06.787" Score="11" Body="&lt;p&gt;Clouds are made up of very tiny liquid water droplets that have small fall speeds.  This means that with just a little bit of upward velocity in the wind, the cloud water can remain aloft and appear to float.  Clouds are not always static blobs -- if you watch some clouds you will see that air can flow through them, condensing into new cloud where it goes in and evaporating into clear air on its way out (&lt;a href=&quot;https://www.youtube.com/watch?v=_roxFGsfzto&quot;&gt;easily visible in mountain wave clouds&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason clouds tend to have a consistent base altitude is due to how temperature and water vapor behave in the boundary layer.  On sunny, windy days the boundary layer is well mixed and potential temperature and water vapor mixing ratio are constant with height.  With a constant &lt;a href=&quot;https://en.wikipedia.org/wiki/Potential_temperature&quot;&gt;potential temperatur&lt;/a&gt;e the actual temperature will decrease at about 10$^\circ$C per kilometer of height.  With constant specific humidity and decreasing temperature as we go upward this means the relative humidity is increasing.  At some height the relative humidity becomes 100% and we call this height the &lt;a href=&quot;https://en.wikipedia.org/wiki/Lifted_condensation_level&quot;&gt;lifted condensation level&lt;/a&gt; (LCL), which will also be the height of the cloud bases.  If surface characteristics are similar across an area, so will be the LCL and this will make all the clouds in the area have similar bases.  You were on the right track with the significant change in air composition, but it is a thermodynamic change with pressure playing a significant role.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-09-09T19:32:06.787" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6515" PostTypeId="1" AcceptedAnswerId="6516" CreationDate="2015-09-09T20:04:29.823" Score="13" ViewCount="16294" Body="&lt;p&gt;Across the whole Earth, about 70% of the surface is water and 30% is land.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I want, though, is to restrict the scope to the &lt;strong&gt;northern hemisphere (NH) only.&lt;/strong&gt; What percentage of NH surface is land?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It would also be good to clarify exactly how we define &quot;land&quot;. If I'm not mistaken, the 70/30 split of water/land actually places inland rivers and lakes as land area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please also cite a source for this. The only google result I found with an answer was yahoo questions.&lt;/p&gt;&#xA;" OwnerUserId="2733" LastEditorUserId="2470" LastEditDate="2016-03-24T02:20:18.707" LastActivityDate="2022-06-02T04:06:50.053" Title="In the northern hemisphere only, what percentage of the surface is land?" Tags="|geography|land-surface|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6516" PostTypeId="2" ParentId="6515" CreationDate="2015-09-09T22:44:52.687" Score="13" Body="&lt;p&gt;From &lt;a href=&quot;http://www.physicalgeography.net/fundamentals/8o.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.physicalgeography.net/fundamentals/8o.html&lt;/a&gt; and &lt;a href=&quot;http://www.eoearth.org/view/article/154984/&quot; rel=&quot;noreferrer&quot;&gt;http://www.eoearth.org/view/article/154984/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The spatial distribution of ocean regions and continents is unevenly arranged across the Earth's surface. In the Northern Hemisphere, the ratio of land to ocean is about 1 to 1.5. The ratio of land to ocean in the Southern Hemisphere is 1 to 4. This greater abundance of ocean surface has some fascinating effects on the environment of the southern half of our planet. For example, climate of Southern Hemisphere locations is often more moderate when compared to similar places in the Northern Hemisphere. This fact is primarily due to the presence of large amounts of heat energy stored in the oceans.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This equates to a measurement of ~40% land in the northern hemisphere.  This agrees with the northern hemisphere azimuthal equal-area map image below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gBOwC.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gBOwC.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The surface area of the Earth covered by lakes and rivers is a fraction of a percent, so their classification does not really change the answer.  However, you would get a slightly different answer if you consider land to be any continental crust (including seas not on ocean crust).  If you define a year and a definition of &quot;land&quot; that you are satisfied with, an exact calculation could be made with GIS software.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;https://www.fba.org.uk/journals/index.php/IW/article/viewFile/502/327&quot; rel=&quot;noreferrer&quot;&gt;https://www.fba.org.uk/journals/index.php/IW/article/viewFile/502/327&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Rivers and streams are likely to cover 0.30–0.56% of the land surface [of Earth]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2015-09-11T20:40:59.697" LastActivityDate="2015-09-11T20:40:59.697" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6517" PostTypeId="1" CreationDate="2015-09-10T03:34:44.190" Score="2" ViewCount="710" Body="&lt;p&gt;&lt;a href=&quot;http://web.archive.org/web/20150905054450/http://www.act.org/qotd/&quot; rel=&quot;nofollow&quot;&gt;An American College Test sample question asks:&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Based on the shadow directions in these experiments, which of the following best describes the difference between the apparent path of the Sun as seen from the observation points in the Northern and Southern Hemispheres?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;A.&lt;/strong&gt; The Sun travels a more southerly path in the Southern Hemisphere than in the Northern Hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;B.&lt;/strong&gt; The Sun travels a more northerly path in the Southern Hemisphere than in the Northern Hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;C.&lt;/strong&gt; The Sun rises in the East and sets in the West in the Northern Hemisphere, but the opposite is true in the Southern Hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;D.&lt;/strong&gt; The Sun rises in the West and sets in the East in the Northern Hemisphere, but the opposite is true in the Southern Hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've read the explanation for B several times. I don't understand the meaning of &quot;traveling a more northerly path&quot; in the southern hemisphere. Does the alignment of the compass and the shadow show the reverse direction in which the sun is traveling? (In this case, since 9 of the 15 directions recorded pointed South, the compass directions were aligned to point North.) &lt;/p&gt;&#xA;" OwnerUserId="4468" LastEditorUserId="725" LastEditDate="2016-08-10T10:12:42.120" LastActivityDate="2016-08-11T16:24:08.683" Title="The apparent path of the sun" Tags="|homework|earth-rotation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6518" PostTypeId="2" ParentId="6517" CreationDate="2015-09-10T04:12:25.157" Score="3" Body="&lt;p&gt;When taking these standardized tests, the first thing to do is to try to solve the problem. If the problem is weirdly stated, as standardized test writers are wont to do, the next thing to do is to eliminate obvious non-answers. (I didn't know that when I took those tests 40+ years ago.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Choices C and D are obviously wrong. The data shows that regardless of hemisphere shadows point more or less to the west at sunrise, east at sunset. Since the shadows point opposite the Sun, this means the Sun rises in the east, sets in the west. This leaves choices A and B as the only viable options.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Try to match columns (days) from tables one and two based on shadow length against choices A and B. Day 1 in table 1 is an exact match against day 2 in table 2. This column doesn't help with answering the question. The other two columns do help. Day 2 in table 1 is most similar to day 1 in table 2, and day 3 in table 1 is most similar to day 3 in table 2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Day 2 in table 1 and day 1 in table 2 are most illustrative. Every shadow in day 2, table 1 has some northward component while every shadow in day 1, table 2 has some southward component. Since the shadows point opposite the Sun, this suggests (B) is the correct answer. This is consistent with the other results.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a sanity check, what about option (A)? This is not consistent with the tabulated results from day 2 in table 1 versus day 1 in table 2, or from day 3 in table 1 versus day 3 in table 2. Option (B) is the only possible answer.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2016-08-11T16:24:08.683" LastActivityDate="2016-08-11T16:24:08.683" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6519" PostTypeId="1" CreationDate="2015-09-10T20:11:50.147" Score="1" ViewCount="49" Body="&lt;p&gt;sir do absence of land plays role in formation of cyclone in south Atlantic ocean and east pacific ocean &lt;/p&gt;&#xA;" OwnerUserId="4470" LastActivityDate="2015-09-10T20:11:50.147" Title="what is the role of absence of land in south atlantic ocean cyclone formation" Tags="|planetary-science|" AnswerCount="0" CommentCount="0" ClosedDate="2015-09-11T03:16:06.970" ContentLicense="CC BY-SA 3.0" />
  <row Id="6524" PostTypeId="2" ParentId="4720" CreationDate="2015-09-12T00:55:39.170" Score="-4" Body="&lt;p&gt;The primary source for the water that generated the flood was neither the upper mantle nor the atmosphere as rainfall, nor cometary bombardment or grazing, but earth's existing ocean water itself. Some water is liberated from the mantle in volcanoes and undersea vents, but these amounts are negligible except over very long periods of time.&#xA;Planet earth has a large amount of radioactive elements in its core and lower mantle. Radioactive element decay sequences, if they occur synchronized, could generate significant and rapid changes in the volume occupied by the elements, therefore, could rapidly change Earth's volume, same as a star can change volume in a collapse towards its core or in red giant phase but by a different process. If earth were to have shrunk, it would have displaced earths oceans to overwhelm the continents in wave after wave of tsunamis. If as the decay sequence continues, earths volume again increased, the water would have been displaced off the continents back into the ocean basins. No extra mystery water is needed to generate the flood, and no mystery as to where all the extra water went after the flood.&#xA;This radioactive decay would have generated massive heat, which would have shut off earth's protective electromagnetic field generating dynamo; however, an expanding earth would also create large rifts, and expose earth's mantle to the oceans, generating mass extinctions in the oceans, massive rainfall in equatorial regions, and massive blizzards at the poles; ergo, the ice ages; extreme cloud cover would have protected earth's life from cosmic rays till the dynamo turned back on; when the EMF turned back on centuries later, with rapid fluctuations, it seems to have generated a memory scrambling effect, recorded as The Tower of Babel event as the scrambling of languages.&lt;/p&gt;&#xA;" OwnerUserId="4476" LastActivityDate="2015-09-12T00:55:39.170" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6525" PostTypeId="1" CreationDate="2015-09-12T15:51:51.573" Score="10" ViewCount="274" Body="&lt;p&gt;I had a homework question: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Given the formula:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;$$\ce{Ca}_x\ce{(PO4)}_y\ce{OH}$$&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Find the lowest possible values of $x,y$ and state (look up) the mineral name.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Based on the anion charges I know, and trying to balance them, I would expect&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\ce{2Ca^{2+} + (PO_{4})^{3-} + OH^{-} -&amp;gt; Ca_{2}(PO_{4})OH}$$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I couldn't find a mineral with this formula, and the closest I could find was hydroxyapatite with the formula:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\ce{Ca_{5}(PO_{4})_{3}OH}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;which is still balanced based on the charges I had initially used, but isn't the same. Can anyone explain why this mineral doesn't form as I had expected?&lt;/p&gt;&#xA;" OwnerUserId="4479" LastEditorUserId="28050" LastEditDate="2015-09-13T20:01:41.757" LastActivityDate="2015-12-30T09:55:49.603" Title="Simplest formula of a calcium phosphate mineral?" Tags="|geochemistry|mineralogy|homework|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6527" PostTypeId="1" CreationDate="2015-09-12T23:37:07.603" Score="17" ViewCount="2531" Body="&lt;p&gt;I've only had a secondary education in physics, so bear with me, but with the greenhouse effect and all, wouldn't we be much hotter already if the ice melt-rate wasn't increasing, since more (heat) energy goes toward changing state, rather than changing temperature? My understanding of latent heat is that it is the applied heat that does not result in a dramatic temperature increase, rather it is used to change state (i.e. solid ice to liquid water).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The obvious issue would be that once the ice is all melted, or it doesn't melt quick enough, we'll have proper heat problems (not just the 2 or 4 or 6 deg changes being discussed now).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there numbers available on this? Or is this effect nonsense? Or am I looking towards a time a few orders of magnitude beyond my years?&lt;/p&gt;&#xA;" OwnerUserId="4481" LastEditorUserId="28050" LastEditDate="2015-09-13T20:09:21.010" LastActivityDate="2022-01-06T08:38:09.467" Title="Is global warming being moderated by latent heat of melting polar ice?" Tags="|climate-change|thermodynamics|" AnswerCount="5" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6528" PostTypeId="1" AcceptedAnswerId="6692" CreationDate="2015-09-13T01:47:27.187" Score="6" ViewCount="455" Body="&lt;p&gt;What is the mass of our planet's atmosphere, hydrosphere, and cryosphere combined? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How accurate can our estimates be?&lt;/p&gt;&#xA;" OwnerUserId="178" LastEditorUserId="178" LastEditDate="2015-09-13T02:35:44.763" LastActivityDate="2015-10-12T16:53:05.273" Title="What is the mass of our planet's atmosphere, hydrosphere, and cryosphere combined?" Tags="|geophysics|atmosphere|ocean|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6529" PostTypeId="1" AcceptedAnswerId="6530" CreationDate="2015-09-13T18:14:01.877" Score="8" ViewCount="1744" Body="&lt;p&gt;My question is simple - how accurate is a tipping-bucket rain gauge?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have read about what causes the errors (wind, bucket mechanics for extreme events, ...) and I know the accuracy is strictly related to the rain rate, in the sense that, e.g., TB gauges tend to highly underestimate in extreme conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I'd like to have a number, say, &lt;em&gt;errors around +-25%&lt;/em&gt;. I know the number itself won't be accurate, it's just to have the order of magnitude. References appreciated, since I myself looked around with no success :-)&lt;/p&gt;&#xA;" OwnerUserId="2423" LastEditorUserId="192" LastEditDate="2015-09-13T18:43:08.033" LastActivityDate="2015-09-26T00:44:35.680" Title="How accurate is a tipping-bucket rain gauge?" Tags="|meteorology|measurements|rainfall|rain|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6530" PostTypeId="2" ParentId="6529" CreationDate="2015-09-13T19:06:19.917" Score="7" Body="&lt;p&gt;The following simulation results shows that the Tipping Bucket estimates suffer from significant errors if based on time scales less than ten to fifteen minutes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Comparison of Tipping-Bucket Error Statistics:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Rs18s.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Rs18s.png&quot; alt=&quot;Comparison of Tipping-Bucket Error Statistics:&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qmz1b.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qmz1b.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jvYel.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jvYel.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&lt;a href=&quot;http://www.ucs.louisiana.edu/~exh5102/Assets/publications/Journal_Papers/14.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Source of above diagrams)&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In this study we attempted to characterize the &lt;em&gt;errors&lt;/em&gt; associated&#xA;  with tipping-bucket rain gauges when used to provide rainfall&#xA;  intensity estimates at small temporal scales. The main source of the&#xA;  TB gauge &lt;em&gt;sampling error&lt;/em&gt; is its sampling mechanism and its inability&#xA;  to capture the small temporal features of the rainfall time series. We&#xA;  found significant error levels in the 1-min estimates especially at&#xA;  low rain rates, but we also found that as the time scale of the&#xA;  computed rain rates increased, the error decreased substantially. With&#xA;  time scales longer than 15 min, the error becomes negligible. &lt;em&gt;The&#xA;  gauge’s performance and its associated errors are sensitive to the&#xA;  applied sampling interval and the bucket volume.&lt;/em&gt; Therefore, we&#xA;  recommend sampling intervals on the order of 5–10 s, along with a&#xA;  bucket size no larger than 0.254 mm (0.01).  Our analysis wasbased on&#xA;  rainfall observations that were mostly dominated by convective storms&#xA;  with few stratiform events. Similar analysis may be needed to&#xA;  investigate the scope of applicability of the developed formulas under&#xA;  different climatological regimes. However, the formulas serve as a&#xA;  first-order approximation that can be used in practical applications. &lt;a href=&quot;http://www.ucs.louisiana.edu/~exh5102/Assets/publications/Journal_Papers/14.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Source)&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user4484" LastEditorDisplayName="user4484" LastEditDate="2015-09-13T19:43:37.910" LastActivityDate="2015-09-13T19:43:37.910" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6532" PostTypeId="1" CreationDate="2015-09-14T13:46:50.273" Score="13" ViewCount="174" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Homo_naledi&quot; rel=&quot;noreferrer&quot;&gt;Homo naledi&lt;/a&gt; was a hominid that has recently made the news, in part because the discovery of a large number of fossils appears to suggest ritual &quot;burials&quot; by a species from 2.5 million years ago, significantly predating those of &lt;em&gt;H. sapiens&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &quot;burial chamber&quot; was found in a cave system at a depth of approximately 30 meters. Given that there should be zero ambient light at that kind of depth, it seems to me that either &lt;em&gt;H. naledi&lt;/em&gt; was very strongly motivated to bury their dead in that particular location (which makes the burials even more amazing), or the chamber has changed it's depth and become significantly deeper than it would likely have been 2.5 million years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it likely that a cave chamber can change it's depth significantly over 2.5 million years? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT&lt;/strong&gt; Added a view of the layout of the burial location cribbed from the New Scientist article... just because it shows how motivated &lt;em&gt;H. naledi&lt;/em&gt; must have been to put their dead where they did.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Uen85.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Uen85.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4488" LastEditorUserId="4488" LastEditDate="2015-09-15T13:38:58.820" LastActivityDate="2018-10-02T12:11:02.997" Title="Could the original H. naledi &quot;burial chamber&quot; have originally been at a shallower depth?" Tags="|earth-history|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="6533" PostTypeId="1" CreationDate="2015-09-13T21:35:28.947" Score="10" ViewCount="605" Body="&lt;p&gt;Quoting from &lt;a href=&quot;http://www-rohan.sdsu.edu/~aty/explain/atmos_refr/horizon.html&quot;&gt;lecture notes of Andrew young at San Diego State University&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;For less extreme, but very reliable, observations, consider some listed by Commander C. L. Garner of the Coast and Geodetic Survey in 1933 [...] He also credits the 1911 sighting of the Fairweather Mountains in Alaska [highest point is Mt. Fairweather 15 325 ft or 4670 m] from the ship &lt;em&gt;Explorer&lt;/em&gt; from the Gulf of Alaska, 330 miles [531 km] away.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Earth’s mean average radius is 3959 miles by a right angled tangent of 330 miles gives a hypotenuse extending well above the surface of the earth of sqrt(3959&lt;sup&gt;2&lt;/sup&gt; + 330&lt;sup&gt;2&lt;/sup&gt;) = 3973 miles. Subtracting the radius 3959 miles gives the drop in the curvature of the earth from the beginning point where the &lt;em&gt;Explorer&lt;/em&gt; made the sighting: 13.7 miles, or 72 492 ft. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;72 492 ft minus Mt. Fairweather’s height 15 325 ft gives 57 167 ft to spare for a whole mountain range to disappear beneath the curvature of the earth.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What could account for this sighting 'through' the curve of the earth?&lt;/p&gt;&#xA;" OwnerDisplayName="Gerald Fluhrer" LastEditorUserId="28050" LastEditDate="2015-09-15T14:23:25.547" LastActivityDate="2017-03-16T09:58:24.700" Title="Is it physically possible to see mountains from 500 km away?" Tags="|atmosphere|mountains|history-of-science|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="6536" PostTypeId="1" CreationDate="2015-09-15T17:09:59.217" Score="5" ViewCount="175" Body="&lt;p&gt;In &lt;em&gt;&lt;a href=&quot;https://books.google.ca/books?id=yRMgYc-8mTIC&amp;amp;lpg=PP1&amp;amp;pg=PA656#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Encyclopedia of Paleoclimatology and Ancient Environments&lt;/a&gt;&lt;/em&gt; by Vivien Gornitz (2008, Springer) it is found that 50 My ago the sea temperature was about 13ºC above the present value.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zBeEf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zBeEf.png&quot; alt=&quot;Screenshot of charts&quot;&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;AFAIK the several proxies gave consistent answers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Why is the temperature always decreasing ?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="2613" LastEditorUserId="28050" LastEditDate="2015-09-16T19:58:20.217" LastActivityDate="2015-09-16T19:58:20.217" Title="Why is the ocean paleotemperature trend downwards?" Tags="|ocean|temperature|paleoclimatology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6537" PostTypeId="2" ParentId="6536" CreationDate="2015-09-15T17:41:12.043" Score="7" Body="&lt;p&gt;I recommend you read the original paper &lt;a href=&quot;http://users.clas.ufl.edu/eemartin/GLY6075F08/LearetalScience%2700.pdf&quot; rel=&quot;noreferrer&quot;&gt;Lear et al. (2000)&lt;/a&gt;. In it they explain that the results are controlled by processes in polar regions and likely associated with the polar surface temperature. The surface temperature will vary considerable depending on the proximity and extend of the deep water formation areas. As these areas are fairly local, relatively small changes in the location and extend of deep water formation can result in deep water temperature being altered. The uncertainty associated with using single cores to estimate global temperatures is thus quite large. What the authors suggest is a predominantly ice-free world during most of the Paleocene and Cretaceous periods and several ice-sheet expansion events during the Oligocene, Miocene and Pleistocene. If there is no ice, the polar and sub-polar deep-water formation is limited and the water temperatures in the deeper part of the ocean is much warmer.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The temperature record shows a general cooling trend for the past 50 My, but its resolution is too low to define abrupt temperature extremes. Assuming that the process of deep water formation at high latitudes prevailed throughout the past 50 My, these deep-ocean temperatures can be inferred to represent polar surface temperatures (1). The temperature trend (Fig. 1C) appears to comprise four main cooling phases separated by periods of more stable temperatures. These cooling phases occur during the early Middle Eocene, the Late Eocene through Early Oligocene, the late Middle Miocene, and the Plio-Pleistocene.&lt;/p&gt;&#xA;&lt;p&gt;Alternative evidence supports the existence of these principal cooling phases. A sharp cooling in the early Middle Eocene has been invoked to explain the abundance of siliceous sediments of this age (20). The Early Eocene warm climate is thought to have promoted in- tense chemical weathering of siliceous rocks at&#xA;high latitudes, which resulted in high concentrations of dissolved silica in the oceans. The subsequent cooling stimulated upwelling of nutrient-rich water and intense biosilicification. The cooling over the Late Eocene through Ear- ly Oligocene is coincident with the transition from “Paleogene” to “transitional” benthic foraminiferal faunas and high extinction rates in planktonic and terrestrial faunas. The initiation of this deep water cooling also coincides with a reduction in the extent of tropical rainforests on land (21, 22). The cooling in the late Middle Miocene is marked by a narrowing of tropical and warm subtropical biotic provinces in terrestrial and marine environments (23). Warmwater diatom assemblages were replaced by cold-water species at this time (24). The Plio-Pleistocene cooling is not represented by an extinction phase in benthic foraminiferal faunas; instead, faunal groups adapted to the changing bottom water conditions by migration (21).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;When you use data from other regions, you get a much different result. For instance, &lt;a href=&quot;ftp://wserv2.esc.cam.ac.uk/pub/harrye/Reprints%20of%20Elderfield%20Publications/2000/2000_Elderfield_Ganssen.pdf&quot; rel=&quot;noreferrer&quot;&gt;Elderfield &amp;amp; Ganssen (2000)&lt;/a&gt; showed how different the temperature changes can be for different species and locations. &lt;a href=&quot;https://i.stack.imgur.com/4wIa8.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4wIa8.gif&quot; alt=&quot;Elderfield Nature paper&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Their data are much more recent and suggest an increase in temperature over the last 20,000 years. As always, everything depends on the temporal scales. One issue that tends to be true is that estimates for periods long time ago tend to have larger uncertainties.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-09-16T01:16:21.513" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6538" PostTypeId="2" ParentId="6536" CreationDate="2015-09-15T17:52:22.610" Score="3" Body="&lt;p&gt;The reference in the figure (where the plot was cropped from - the period 70M-50M years is missing) is helpful. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The resolution on that plot is quite low but it can be seen that, for the past 50M years, the temperature is not always decreasing. There appear to be four main cooling trends flanked by periods of constant or increasing temperatures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the authors, the long-term cooling trend is a result of several processes that work together in a nonlinear way to modify the distribution of heat on the surface of the Earth. However, we require many more global records of temperature before we are able to quantify their respective contributions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the paper:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The long-term cooling over this period is thought to have resulted&#xA;  from a combination of factors that altered the amount and distribution&#xA;  of heat over Earth’s surface. Variations in atmospheric greenhouse&#xA;  gases (principally CO2), Earth’s albedo, and linked changes in&#xA;  ocean-atmosphere circulation patterns, which are also influenced by&#xA;  the opening and closing of ocean gateways, could contribute to this&#xA;  long-term cooling.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Lear, Caroline Helen, H. Elderfield, and P. A. Wilson. &lt;strong&gt;&quot;Cenozoic deep-sea temperatures and global ice volumes from Mg/Ca in benthic foraminiferal calcite.&quot;&lt;/strong&gt; science 287.5451 (2000): 269-272.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Actual figure from the original paper:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hxQhT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hxQhT.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="200" LastActivityDate="2015-09-15T17:52:22.610" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6539" PostTypeId="1" AcceptedAnswerId="6542" CreationDate="2015-09-15T20:22:34.770" Score="6" ViewCount="9838" Body="&lt;p&gt;If I were to bury something 10 feet (~3 metres) underground, with loose soil on top, would the ground naturally compact itself over time, until whatever I had buried has dirt tightly pressing against it on all sides?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What if I buried it 50 feet (~15 metres) underground?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If it exists, what is this compaction process called and how does it happen?&lt;/p&gt;&#xA;" OwnerUserId="4494" LastEditorUserId="725" LastEditDate="2016-09-17T00:52:31.533" LastActivityDate="2016-09-17T00:52:31.533" Title="Does dirt compact itself over time? If so, how does this happen?" Tags="|geophysics|sedimentology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6540" PostTypeId="2" ParentId="6539" CreationDate="2015-09-16T00:58:18.380" Score="1" Body="&lt;p&gt;From Bjørlykke (2003) &lt;a href=&quot;http://dx.doi.org/10.1007/978-1-4020-3609-5_53&quot; rel=&quot;nofollow&quot;&gt;Compaction (consolidation) of sediments&lt;/a&gt;, in Encyclopedia of Earth Science:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Compaction may be defined as the process by which the sediment volume is reduced and the sediment density increased. Sediments change their physical properties after deposition due to the stress from the overburden (gravitational compaction) and as a result of biological or chemical reactions involving dissolution and precipitation of minerals. In some sediments compaction of amorphous materials like organic material (kerogen) and biogenic silica (Opal A) also play an important role. All natural processes modifying sediments after deposition are in geological literature referred to as diagenesis (q.v.) and this term also includes compaction processes. Soil engineers use the term compaction to describe densifications on the laboratory and in the field by vibrations of mechanical equipment to reduce the pore volume and consolidation for the expulsion and flow of water in soils.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-09-16T00:58:18.380" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6541" PostTypeId="1" CreationDate="2015-09-16T03:32:20.473" Score="7" ViewCount="393" Body="&lt;p&gt;I'm trying to understand why the summer (January) precipitations in Venezuela are so low in the central and southern parts of the country as well as in eastern Colombia. The most plausible explanation I could find was a rain-shadow effect but unless I'm wrong, the mountains are on the northern side while the winds are blowing from the ocean, east to west. This should not result in a dry season. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What have I missed?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My references are : &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://research.jisao.washington.edu/data_sets/ud/samerica/&quot; rel=&quot;noreferrer&quot;&gt;http://research.jisao.washington.edu/data_sets/ud/samerica/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://kids.britannica.com/comptons/art-166714/The-map-at-left-shows-the-wind-belts-of-the&quot; rel=&quot;noreferrer&quot;&gt;http://kids.britannica.com/comptons/art-166714/The-map-at-left-shows-the-wind-belts-of-the&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="966" LastEditorDisplayName="user1066" LastEditDate="2021-06-18T15:32:59.410" LastActivityDate="2021-06-18T15:32:59.410" Title="Why is Venezuela so dry?" Tags="|atmosphere|climate|rainfall|coastal-desert|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6542" PostTypeId="2" ParentId="6539" CreationDate="2015-09-16T04:01:48.140" Score="3" Body="&lt;p&gt;Soil is a collection of various sized minerals grains, of various types of minerals produced by the weathering of rock. Typical soil minerals are clays, silts and sands.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The properties and behavior of different soil types depends of the composition of the soil: the proportion of clays, silts and sand in a soil. Sandy soils are well draining and clayey soils are sticky.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Between the grains of minerals that comprise a soil are spaces, called pores or pore spaces. The pores can be filled with either water or air, depending the location of water tables and wetting events like rain, snow melts or other forms of water inundation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The density of a soil is dependent on the degree of &lt;a href=&quot;https://en.wikipedia.org/wiki/Soil_compaction&quot; rel=&quot;nofollow&quot;&gt;compaction&lt;/a&gt; of the soil. For to a soil to be compacted, a stress has to be applied to the soil to realign the grains of soil which reduces the total volume of the pores and reduces the amount of &lt;strong&gt;air&lt;/strong&gt; within the pores.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Consolidation&lt;/em&gt;&lt;/strong&gt; of a soil occurs when pore space is reduced and &lt;strong&gt;&lt;em&gt;water&lt;/em&gt;&lt;/strong&gt; in a soil is displaced due to an applied stress.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding having something buried and soil compacting around it over time, yes that will occur but it is a question of how much stress the soil experiences, the duration of time and the nature of the soil - sandy or clayey. Something buried for a day without any stresses not much will happen. But, something buried for thousands of years with people and animals walking over it, rain falling on the soil, vibrations from nearby human activity and an occasional earthquake all add to the stresses the soil will experience and increases the degree of compaction or consolidation over time.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-09-16T04:01:48.140" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6543" PostTypeId="1" AcceptedAnswerId="6548" CreationDate="2015-09-16T09:10:42.833" Score="11" ViewCount="985" Body="&lt;p&gt;Messing around on Google Earth recently I noticed a number of striations in the Eastern Pacific. These appear in an East-West orientation and seem to start on the North and South American continental shelves, and extend for roughly half the Pacific Ocean. For example one of these striations start in Santa Rosa Island off California and ends at Hawaii. These striations also appear to be roughly equally spaced at 8 degree intervals. The North and South American striations are angled with respect to each other and seem to converge at roughly Tahiti.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What causes these? I'm a fascinated novice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some images to make things clearer (North Pole is top left):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note the regularly spaced East-West parallel striations starting from the Equator and stepping north. In fact the striation on the Equator covers the entire Pacific.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LVJJZ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LVJJZ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here a closer shot also shows fainter striations fanning out from Los Angeles:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PCBk8.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PCBk8.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4496" LastEditorUserId="22648" LastEditDate="2021-11-05T09:46:44.427" LastActivityDate="2021-11-05T09:46:44.427" Title="What are the striations or ridges in the eastern Pacific Ocean?" Tags="|geophysics|oceanography|topography|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6544" PostTypeId="1" CreationDate="2015-09-16T11:33:48.013" Score="6" ViewCount="1715" Body="&lt;p&gt;I'm currently on holiday in Indonesia. In my travel guide I was reading about the island Samosir, which I'm visiting in a few days. I read that the island, which is located in lake Toba, is connected to the main island of Sumatra by an isthmus. This got me wondering whether this wouldn't technically make Samosir island a peninsula. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my question is: what (if anything) is the technical difference between a peninsula and an island connected to its parent landmass by an isthmus?&lt;/p&gt;&#xA;" OwnerUserId="4497" LastEditorUserId="662" LastEditDate="2015-09-20T13:13:08.863" LastActivityDate="2015-09-26T06:21:55.003" Title="When does an island with isthmus become a peninsula?" Tags="|land-surface|geomorphology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6545" PostTypeId="2" ParentId="6543" CreationDate="2015-09-16T12:02:49.213" Score="3" Body="&lt;p&gt;Several data sources with very different resolutions are combined in such maps, for example &lt;a href=&quot;https://en.wikipedia.org/wiki/European_Remote-Sensing_Satellite&quot; rel=&quot;nofollow&quot;&gt;gravity measurements from satellites&lt;/a&gt; and echo sounding (there is also a wikpedia article on that, I can only post 2 links) on board ships.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.gebco.net/about_us/gebco_science_day/documents/abramova_poster_gebco_2013.pdf&quot; rel=&quot;nofollow&quot;&gt;&quot;[L]inear artifacts such as artificial 'ridges' and&#xA;'troughs' &quot;&lt;/a&gt; are artifacts from combining high resolution data from ship tracks which tends to be available in the pattern you observed with low resolution data from gravimetry.&lt;/p&gt;&#xA;" OwnerUserId="2861" LastEditorUserId="2861" LastEditDate="2015-09-16T12:12:29.417" LastActivityDate="2015-09-16T12:12:29.417" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6546" PostTypeId="2" ParentId="6492" CreationDate="2015-09-16T13:06:22.723" Score="1" Body="&lt;p&gt;Although the bedrock is indeed fairly resistant to erosion on the timescales considered for braided riverbeds, even the hardest rocks eventually erode because of all kinds of physical and chemical weathering. What you will often see in the mountains that at the most upstream ends of a mountainstream the streambed is dominated by huge rocks. These are only moved during heavy rainfall events or after a lot of time when erosion causes them to fall apart. The finer fractions are easily transported because of water and ice flowing over, and gravity pulling the sediment down the slopes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the bottom of the main valleys through the mountains the gradient is typically somewhat lower causing a lot of sediment to be deposited, leading to a fairly erodable riverbed. In this case it is therefore not so much erosion of the bedrock, but of the &lt;em&gt;riverbed&lt;/em&gt;.&lt;/p&gt;&#xA;" OwnerUserId="79" LastActivityDate="2015-09-16T13:06:22.723" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6547" PostTypeId="1" CreationDate="2015-09-16T16:22:31.660" Score="4" ViewCount="90" Body="&lt;p&gt;Please refer to &lt;a href=&quot;http://www.coastalwiki.org/wiki/Monitoring_coastal_morphodynamics_using_high-precision_multibeam_technology#Limitations_and_Problems&quot; rel=&quot;nofollow&quot;&gt;this page of coastal wiki&lt;/a&gt;. Quoting:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...the reconstructed overall vertical position [of the seabed] with respect to a fixed chart datum may vary by more than 10 cm from survey to survey. The causes of this variation have not been resolved yet.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What could cause this? Could it be a tidal effect? &lt;strong&gt;Is there any new information available (specifically on this case)?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt; Just to make things clear, I am aware of seabed sonars and their typical error terms, I am aware of coastal morphodynamics - I am looking forward to see if there is any information available attributing a (definite) cause to event described in the wiki page. I also highlighted the relevant part of the question.&lt;/p&gt;&#xA;" OwnerUserId="313" LastEditorUserId="313" LastEditDate="2015-09-24T18:24:34.317" LastActivityDate="2015-09-24T18:24:34.317" Title="What causes variation of seabed depth relative to fixed chart datum?" Tags="|measurements|sea-level|dynamics|coastal|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6548" PostTypeId="2" ParentId="6543" CreationDate="2015-09-16T17:00:51.773" Score="8" Body="&lt;p&gt;&lt;strong&gt;They are &lt;a href=&quot;https://en.wikipedia.org/wiki/Fracture_zone&quot; rel=&quot;noreferrer&quot;&gt;fracture zones&lt;/a&gt;.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've annotated your image with the names of these very long, tectonically important features. They even have names, such as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mendocino_Fracture_Zone&quot; rel=&quot;noreferrer&quot;&gt;Mendocino Fracture Zone&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ceZqX.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ceZqX.jpg&quot; alt=&quot;Fracture zones in the northeastern Pacific&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also labelled some survey tracks (rather subtle, very straight, very regular in width), which are data artifacts — these are the things you noticed radiating from the vicinity of Los Angeles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are yet other types of linear feature on the sea floor:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Transform_fault&quot; rel=&quot;noreferrer&quot;&gt;Transform faults&lt;/a&gt; are strike-slip faults connecting segments of spreading centres in the oceanic crust.&lt;/li&gt;&#xA;&lt;li&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Mid-ocean_ridge&quot; rel=&quot;noreferrer&quot;&gt;spreading centres&lt;/a&gt; themselves.&lt;/li&gt;&#xA;&lt;li&gt;Roughly linear archipelagos like Hawaii.&lt;/li&gt;&#xA;&lt;li&gt;The long, curved trenches at &lt;a href=&quot;https://en.wikipedia.org/wiki/Convergent_boundary&quot; rel=&quot;noreferrer&quot;&gt;convergent plate margins&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Images from Google Maps. Note: I edited this answer substantially after the OP clarified the question... and I learned about &lt;a href=&quot;http://www.columbia.edu/~vjd1/MOR_transforms.htm&quot; rel=&quot;noreferrer&quot;&gt;the difference between transform faults and fracture zones&lt;/a&gt;.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2015-09-17T00:03:53.463" LastActivityDate="2015-09-17T00:03:53.463" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6549" PostTypeId="1" AcceptedAnswerId="6550" CreationDate="2015-09-16T19:59:02.023" Score="8" ViewCount="372" Body="&lt;p&gt;Are there any resources (books/links) that discuss the mathematical tools and methods used to forecast the aurora borealis activity in a particular location?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I see many websites that claim to predict aurora, but are there any open source code that lets you have an idea of the models?&lt;/p&gt;&#xA;" OwnerUserId="637" LastEditorUserId="28050" LastEditDate="2015-09-16T20:04:28.183" LastActivityDate="2015-09-17T00:37:33.770" Title="What modelling approaches are used to predict the aurora?" Tags="|models|auroras|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6550" PostTypeId="2" ParentId="6549" CreationDate="2015-09-17T00:37:33.770" Score="5" Body="&lt;p&gt;&lt;strong&gt;One model is the &lt;a href=&quot;http://sd-www.jhuapl.edu/Aurora/ovation/&quot;&gt;OVATION auroral precipitation model&lt;/a&gt;.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;OVATION &lt;a href=&quot;https://en.wikipedia.org/wiki/Backronym&quot;&gt;stands for&lt;/a&gt; Oval  Variation,  Assessment,  Tracking,  Intensity, and  Online  Nowcasting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://www.swpc.noaa.gov/&quot;&gt;NOAA Space Weather Prediction Center&lt;/a&gt; uses the OVATION Prime model for their 30-minute aurora forecast. They use a modified version of the model for their &lt;a href=&quot;http://www.swpc.noaa.gov/products/aurora-3-day-forecast&quot;&gt;3-day forecast&lt;/a&gt;. It was devised by Newell et al. (2010) at Johns Hopkins University. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can read all about it in Machol et al. (2013). &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2011SW000746/full&quot;&gt;The paper&lt;/a&gt; is open access and contains several equations and a description of the method. They explain:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The OVATION Prime model is derived from electron and proton&#xA;  flux measurements from the SSJ4 detectors on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Defense_Meteorological_Satellite_Program&quot;&gt;DMSP satellites&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;SSJ4 sensors, according to &lt;a href=&quot;http://www.ferzkopp.net/Personal/Thesis/node28.html&quot;&gt;one source&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;[...consist] of an array of four cylindrical, curved plate, electrostatic analyzers configured into two pairs; one pair each to measure electrons and ions. Each pair covers the energy range from 30 eV to 30 keV in 20 channels spaced at equal intervals in energy on a logarithmic scale. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;h3&gt;References&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Machol, J. L., J. C. Green, R. J. Redmon, R. A. Viereck, and P. T. Newell (2012), Evaluation of OVATION Prime as a forecast model for visible aurorae, Space Weather, 10, S03005, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2011SW000746/full&quot;&gt;doi:10.1029/2011SW000746&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Newell, P. T., T. Sotirelis, and S. Wing (2010a), Seasonal variations in diffuse, monoenergetic, and broadband aurora, J. Geophys. Res., 115, A03216, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2009JA014805/full&quot;&gt;doi:10.1029/2009JA014805&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-09-17T00:37:33.770" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6551" PostTypeId="2" ParentId="5169" CreationDate="2015-09-17T03:27:48.590" Score="6" Body="&lt;p&gt;From &lt;a href=&quot;http://www.srh.noaa.gov/eax/?n=holtmorecrain1947&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.srh.noaa.gov/eax/?n=holtmorecrain1947&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A very moist airmass was in place across Missouri during the afternoon and evening of 22 June 1947, as evident by dewpoint temperatures in the middle 70s across Missouri during the afternoon hours&lt;/p&gt;&#xA;&lt;p&gt;Advances in meteorological science led Locatelli to speculate that the thunderstorm that produced the historic rainfall of 22 June 1947, did not develop along a classic surface cold front, but to the east of a surface dryline (drytrough) and underneath a cold front aloft that had origins in the Mexican plateau.  Regardless of the causative surface and upper air features, a complex of storms at a scale not measured well in the data-spare period of the 1940s developed near Kansas City and moved across Holt, Missouri, depositing 12 inches of rain in less than one hour.  Rain continued to fall on Holt after the 12 inch deluge for the next couple hours, but only amounted to an additional one-half inch.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;A rare meteorological event occurred that day.  I offer a semi-empirical frame of reference that takes  into account that the most extreme rainfall rates occur for a short duration (e.g. a few minutes).&lt;/p&gt;&#xA;&lt;p&gt;In &amp;quot;A methodology to classify extreme rainfall events in the western mediterranean area&amp;quot; by Casas et al., (2004):&#xA;&lt;a href=&quot;http://link.springer.com/article/10.1007%2Fs00704-003-0003-x&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://link.springer.com/article/10.1007%2Fs00704-003-0003-x&lt;/a&gt;&#xA;they show rain rates of up to 0.5 cm/min sustained for several minutes (based on a large network of rain monitors in Barcelona).   IF that could somehow be sustained for an hour, that would give a rate of 30 cm/hr (which is what Holt saw).&lt;/p&gt;&#xA;&lt;p&gt;For comparison, the most extreme rainfall rate measured in one minute in the USA is 3.1 cm (1.2 in; see &lt;a href=&quot;http://wmo.asu.edu/world-greatest-one-minute-rainfall&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://wmo.asu.edu/world-greatest-one-minute-rainfall&lt;/a&gt; ). Actual rain doesn't continue at such an extreme rate for much longer, but would equate to 186 cm per hour (6 times what Holt, Missouri saw in 1946).  The link that kwinkunks provides &lt;a href=&quot;http://www.bom.gov.au/water/designRainfalls/rainfallEvents/worldRecRainfall.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.bom.gov.au/water/designRainfalls/rainfallEvents/worldRecRainfall.shtml&lt;/a&gt; shows a world rate record of 3.8 cm/min which, if sustained, would equate to 228 cm per hour.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-09-18T02:20:54.807" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6552" PostTypeId="1" AcceptedAnswerId="6555" CreationDate="2015-09-17T01:40:42.540" Score="9" ViewCount="426" Body="&lt;p&gt;The context of this question is computational earth science specifically meteorology/climatology but I am sure it applies to all the scientific disciplines where numerical methods are used.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recently I had asked the author of a peer reviewed paper for the software that was used in the publication of his paper. He not only  immediately provided the software but also gave me test data to verify the results of his paper. The same was done by a climate change institute affiliated to NOAA. They gave me their software and asked me to download the relevant data from the NOAA site to validate their conclusions and perhaps reuse their software for solving my problems. In both these cases the only requirement was that the software had to be cited in any paper that I publish in the future.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These two instances are not the problem. In another couple of cases when I asked the authors of the peer reviewed paper for their software to validate their work they refused claiming that is &quot;private&quot;. My questions are therefore:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Which one of these two  occurrences is more common in meteorology/climatology?&lt;/li&gt;&#xA;&lt;li&gt;As somebody who is originally from a CS background (where code reviews are extremely common) I'm curious what is the current standard of reproducibility in meteorology/climatology?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerDisplayName="user1066" LastEditorUserId="64" LastEditDate="2015-09-18T17:21:16.063" LastActivityDate="2015-09-18T21:05:16.490" Title="Paper result validation and the scientific method in earth science" Tags="|meteorology|climatology|reproducibility|" AnswerCount="3" CommentCount="5" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6553" PostTypeId="2" ParentId="6552" CreationDate="2015-09-17T04:12:32.347" Score="3" Body="&lt;p&gt;Most Earth-Science models are comprised of several sub-models that are developed by multiple members of the international community, requiring an open-source framework to be successful long-term.  However, sometimes there are model developments that are done by a consulting company which may have caveats as to how the code can be distributed.  Or, you may have a grant that is funded by a private source that can dictate who has access to the final product.  So, it really does depend on the source of the money and what the terms of the grant are.  Some privately funded products do become well-recognized in the Earth Science community, but it is quite rare, and typically the fundamental equations are published.   Sometimes its something as simple as confidential business data that is embedded in the code logic. You can get access to the executable and still do your own testing, but the code itself is private.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Usually, though, Earth Science computational models are developed with grant money that comes from publicly funded agencies like the National Science Foundation, NASA, or NOAA.  In these cases, the end-product is by definition open-source and will be shared with the scientific community.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2015-09-18T19:38:04.243" LastActivityDate="2015-09-18T19:38:04.243" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6554" PostTypeId="2" ParentId="6552" CreationDate="2015-09-17T05:45:08.517" Score="3" Body="&lt;p&gt;In addition to the answer by farrenthorpe, the other way to try to valid someone's results is to develop procedures and computer programs yourself, from first principles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a lot more tedious and time consuming and can be difficult, particularly for complex models and data. However, it is a method by which validation can be confirmed or refuted &lt;em&gt;independently&lt;/em&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-09-17T05:45:08.517" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6555" PostTypeId="2" ParentId="6552" CreationDate="2015-09-17T06:21:20.750" Score="5" Body="&lt;p&gt;Let's start with the trivially true: programming is not earth science; earth science is not programming. Programming is one tool of many in earth science. In programming, the end result is the program itself. In earth science, that's never the case: but one end result is algorithms developed that inform us about the real world, and implemented in a progam.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What if there is a bug in a peer-reviewed paper? Well, of course there is, just as there are bugs in pretty much every program that does anything useful in the real world. So what?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Validating source code is  the domain of programming. Validating algorithms and observations is the domain of earth science. Re-running someone else's code with the same input data is barely any kind of validation at all, and rarely the interesting kind. Taking someone else's algorithms and implementing them yourself, that's the sort of validation I see across the physical, life, social sciences.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I don't see someone else's source code? No big deal. Indeed, that's often a good thing: it means I can genuinely clean-room their algorithm.&lt;/p&gt;&#xA;" OwnerUserId="100" LastActivityDate="2015-09-17T06:21:20.750" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6556" PostTypeId="1" CreationDate="2015-09-18T05:57:20.340" Score="2" ViewCount="522" Body="&lt;p&gt;Please clarify my doubt regarding the question.It was asked in my examination.&#xA;In the South Atlantic and South-Eastern Pacific regions in tropical latitudes, cyclone does not originate. What is the reason?&#xA;(a) Sea surface temperatures are low&#xA;(b) Inter-Tropical Convergence Zone seldom occurs&#xA;(c) Coriolis force is too weak&#xA;(d) Absence of land in those regions&lt;/p&gt;&#xA;" OwnerUserId="4506" LastActivityDate="2015-09-18T05:57:20.340" Title="What is the reason for absence of cyclone in south atlantic and south eastern pacific" Tags="|tropical-cyclone|" AnswerCount="0" CommentCount="1" ClosedDate="2015-09-18T13:24:23.100" ContentLicense="CC BY-SA 3.0" />
  <row Id="6557" PostTypeId="2" ParentId="4798" CreationDate="2015-09-18T08:50:06.683" Score="2" Body="&lt;p&gt;He's correct, there is precious little uranium or thorium  in the Earth's core. He's also right that an extra source of heat is required to drive the core's magnetism. Note however that, as has been known for a long time, the Earth's core is less dense than would be the case if it was pure Ni-Fe alloy. The answer is that there is a lot of sulphur down there, in fact about 10% of the moon's weight in sulphur, which most likely exists as high pressure Fe-sulphide phases. Potassium is a lithophile element and would not normally exist in the core, but potassium is soluble in Fe-sulphide. The radionuclide 40-potassium, in the sulphide, in the core, is the source of the missing heat which drives the dynamo which has created the Earth's magnetism for more vthan 3.5 billion years. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-09-18T08:50:06.683" CommentCount="13" ContentLicense="CC BY-SA 3.0" />
  <row Id="6558" PostTypeId="1" AcceptedAnswerId="6564" CreationDate="2015-09-18T14:54:25.300" Score="5" ViewCount="108" Body="&lt;p&gt;Are there any publicly available models that show you how to accurately predict the salmon run in both the Pacific and Atlantic oceans?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This has been such a long interest of mine, I often see the results of this study, but I have never seen the methodology used for prediction.&lt;/p&gt;&#xA;" OwnerUserId="637" LastActivityDate="2015-09-19T20:26:51.733" Title="How to create a model to predict the salmon run" Tags="|oceanography|models|canada|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6560" PostTypeId="1" CreationDate="2015-09-18T23:11:05.103" Score="1" ViewCount="14423" Body="&lt;p&gt;How is apparent dip related to true dip?  How can true dip be calculated from apparent dip?&lt;/p&gt;&#xA;" OwnerUserId="4499" LastEditorUserId="543" LastEditDate="2015-09-19T01:41:28.143" LastActivityDate="2015-09-19T01:41:28.143" Title="In geology, what is apparent dip and how is it related to true dip?" Tags="|geology|geometry|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6561" PostTypeId="2" ParentId="6560" CreationDate="2015-09-19T01:31:36.207" Score="6" Body="&lt;p&gt;From &lt;a href=&quot;https://en.wikipedia.org/wiki/Strike_and_dip&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Strike_and_dip&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Apparent dip is the name of any dip measured in a vertical plane that is not perpendicular to the strike line. True dip can be calculated from apparent dip using trigonometry if you know the strike. Geologic cross sections use apparent dip when they are drawn at some angle not perpendicular to strike.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;see &lt;a href=&quot;http://www.webpages.uidaho.edu/~simkat/geol345_files/2012lab2.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.webpages.uidaho.edu/~simkat/geol345_files/2012lab2.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/U5tWo.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/U5tWo.jpg&quot; alt=&quot;apparent dip&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2015-09-19T01:31:36.207" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6562" PostTypeId="2" ParentId="6533" CreationDate="2015-09-19T05:25:09.600" Score="6" Body="&lt;p&gt;I think what was observed is a superior mirage. A superior mirage occurs when warm air overlies a very cold layer of air, aka an inversion. You don't often see a superior mirage in lower latitudes, but they seem to be somewhat common in and near the Arctic regions.&lt;br&gt;&lt;br&gt;With normal atmospheric conditions and taking into consideration refraction, about the furthest one could see a 15,325 foot mountain from, say, a 100 foot high deck is roughly 177 miles, depending on the tide. The only possible explanation is a very strong superior mirage.&lt;br&gt;&lt;br&gt;There are a couple of good articles &lt;a href=&quot;https://nsidc.org/cryosphere/arctic-meteorology/phenomena.html&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;http://www.eoearth.org/view/article/156343/&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; that describe the conditions necessary:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IurSN.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IurSN.gif&quot; alt=&quot;towering image as seen from shore&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2959" LastEditorUserId="543" LastEditDate="2015-09-19T17:07:19.500" LastActivityDate="2015-09-19T17:07:19.500" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6563" PostTypeId="2" ParentId="6509" CreationDate="2015-09-19T10:01:03.590" Score="2" Body="&lt;p&gt;There isn't a lot written on this yet. A search of FAO, UNESCO, World Bank and Asia Development Bank should turn up answers for specific regions. Keep in mind that climatic modelling is generally quite accurate for temperature, but woefully inaccurate in terms of regional water resources assessment. One should rely as much upon instrumental evidence-based historic trends as upon global climatic models and their down-scaled derivatives. In terms of temperature the important issue is to develop higher temperature tolerant crop cultivars, and maybe totally new crops. For example, fruit orchards that require so many days of frost will not do well under global warming, but new genetically engineered crops might do spectacularly better. The main issue is increased crop-water demand combined with diminishing irrigation water availability. In this, improving the irrigation efficiency is crucial, and requires massive reforms in almost every country. Apart from rising sea level, efficient irrigation combined with an upgrade to modern farming practices is by far the most important climate change adaptation. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-09-19T10:01:03.590" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6564" PostTypeId="2" ParentId="6558" CreationDate="2015-09-19T20:26:51.733" Score="4" Body="&lt;p&gt;You can use a program called Stella (which costs money) but there is also a free program that does nearly the same thing called Vensim.  These software packages allow you to build simple dynamic models using a GUI interface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The materials (including salmon run scenario model files) for Andy Ford's &quot;Modeling the Environment&quot; class, which he taught for  many years, are here: &#xA;&lt;a href=&quot;http://public.wsu.edu/~forda/models.html&quot; rel=&quot;nofollow&quot;&gt;http://public.wsu.edu/~forda/models.html&lt;/a&gt;&#xA;with the &quot;Smolts Migration Model&quot; and &quot;Salmon Harvest Simulator&quot; prebuilt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;His text can be obtained online, the title is&#xA;&quot;Modeling the Environment: An Introduction To System Dynamics Modeling Of Environmental Systems&quot;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Andrew Ford is Professor of Environmental Science and Regional Planning at Washington State University. He teaches modeling with an emphasis on environmental problems in the west, and he is the author of the Island Press text on Modeling the Environment. He uses the system dynamics approach to modeling, and he is the recipient of the Jay W. Forrester Award for the outstanding contribution to the field of system dynamics.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastActivityDate="2015-09-19T20:26:51.733" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6565" PostTypeId="2" ParentId="765" CreationDate="2015-09-19T22:06:15.090" Score="13" Body="&lt;p&gt;@Peter Jansson provides a much more thorough answer, but for a quick conversion of expected liquid water equivalent to expected snow depth:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1 inch liquid water = 10 inches snow for warm storms&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1 inch liquid water = 20 inches snow for cold storms&lt;/p&gt;&#xA;&#xA;&lt;p&gt;or&lt;/p&gt;&#xA;&#xA;&lt;p&gt;25 mm = 25 cm for warm storms&lt;/p&gt;&#xA;&#xA;&lt;p&gt;25 mm = 50 cm for cold storms&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Often a certain climatology will trend one way in these numbers, e.g. maritime winter climates such as in California tend to get warmer storms so you generally get between 10 and 15 in/in  and in Utah/Colorado which have continental climates you generally expect 15-20 in/in unless it's late spring.&lt;/p&gt;&#xA;" OwnerUserId="4514" LastActivityDate="2015-09-19T22:06:15.090" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6566" PostTypeId="1" CreationDate="2015-09-20T07:20:34.730" Score="7" ViewCount="754" Body="&lt;p&gt;With global warming comes rising sea levels. This has been going on for at least fifty years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RXWX2.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RXWX2.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So haven't there been some islands that have been swallowed by now? An island could be nothing more than a rock jutting up a few centimeters out of the sea. There are many such &quot;rock&quot; islands that surround larger islands, and I'm wondering if any have been devoured by now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't need a whole list of such islands, although a link to such a list would be probably the best answer one could hope for. What I'm really looking for is a few examples, or maybe the largest island known to have disappeared thanks to the rising sea.&lt;/p&gt;&#xA;" OwnerUserId="2733" LastEditorUserId="5594" LastEditDate="2018-11-09T23:16:20.090" LastActivityDate="2018-11-09T23:16:20.090" Title="Have there ever been any islands that disappeared due to rising sea level?" Tags="|climate-change|earth-history|sea-level|erosion|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="6567" PostTypeId="2" ParentId="6547" CreationDate="2015-09-20T09:56:58.687" Score="2" Body="&lt;p&gt;Your question is actually a three-part question in disguise, of which I cannot answer all parts, but let me tell you what I do know.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Part 1: What causes variations in vertical position within the context of the refered sentence?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;If you read that section more carefully it is not so much variation of the seabed depth, but variation in the &lt;em&gt;measurement&lt;/em&gt; of the seabed depth. Using known fixed structures on the seabed they found out that different runs give a different vertical position of these structures. Let me expand your quote:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;[...] Repeated sampling of stable immobile seabed structures (fishing drag-board traces, ship wrecks) indicates that the reconstructed overall vertical position with respect to a fixed chart datum may vary by more than 10 cm from survey to survey. The causes of this variation have not been resolved yet. Hence, without a vertical reference present within the surveyed area overall variations in the seabed of less than 20 cm cannot be derived unambiguously over periods longer than several months. In contrast, using a fixed seabed structure as vertical reference the precision of multibeam data can be less then half a meter in the horizontal and one centimetre in the vertical [...]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This means that in situations without stable vertical references measurements at different times cannot be compared easily, and simply subtracting the bed heights would not necessarily give the change in bed height over the elapsed time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, when there are stable structures, such as a ship's wreck, you can use the difference in the measurements of the vertical position of that structure to correct measurements of the entire seabed, giving a much better vertical precision.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Part 2: What causes variations in the measurements between measurement runs?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The section referenced mentions that the exact causes of the different measurements have not been resolved. Most likely it is a combination of inaccuracies of the used instruments, on which I'm definitely not an expert, and I'm not even sure this is the right Stack Exchange to ask that question.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Part 3: What causes true variations in the absolute seabed height?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;This is an entire field of research on its own, called coastal morphodynamics, which is too broad to be answered in a single Stack Exchange answer. Without a specific question you wouldn't get a more sensible answer than it a depends on the seabed composition and water flow.&lt;/p&gt;&#xA;" OwnerUserId="79" LastEditorUserId="79" LastEditDate="2015-09-20T14:26:00.480" LastActivityDate="2015-09-20T14:26:00.480" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6568" PostTypeId="2" ParentId="6566" CreationDate="2015-09-20T13:24:54.600" Score="9" Body="&lt;p&gt;&lt;strong&gt;Definitely, there are lots.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you say, sea-level is rising in most (&lt;a href=&quot;https://earthscience.stackexchange.com/questions/4728/why-is-relative-sea-level-falling-in-hudson-bay&quot;&gt;but not all&lt;/a&gt;) coastal areas. Indeed, at the end of the last ice age ca. 12,000 years ago, &lt;a href=&quot;https://en.wikipedia.org/wiki/Post-glacial_rebound#Global_sea_levels&quot; rel=&quot;nofollow noreferrer&quot;&gt;sea-levels rose&lt;/a&gt; about 120 m. Many islands and land bridges — such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Beringia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Beringia&lt;/a&gt; across the Bering Strait, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Doggerland&quot; rel=&quot;nofollow noreferrer&quot;&gt;Doggerland&lt;/a&gt; across the North Sea — drowned.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can't find any lists of drowned islands, but here are some places you will find them today and in the geological past:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;'Banks' on the eastern seaboard of North America&lt;/strong&gt; would have been emergent during the ice age — &lt;a href=&quot;http://www.amnh.org/explore/science-bulletins/bio/documentaries/will-the-fish-return/the-sorry-story-of-georges-bank&quot; rel=&quot;nofollow noreferrer&quot;&gt;Georges Bank&lt;/a&gt; and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Grand_Banks_of_Newfoundland&quot; rel=&quot;nofollow noreferrer&quot;&gt;Grand Banks&lt;/a&gt; for example. As they drowned, they would have formed islands — lots, in the case of Grand Bank.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;The Hawaiian archipelago&lt;/strong&gt; is part of &lt;a href=&quot;https://en.wikipedia.org/wiki/Hawaiian%E2%80%93Emperor_seamount_chain&quot; rel=&quot;nofollow noreferrer&quot;&gt;a famous chain&lt;/a&gt; of drowned islands, but the change in sea-level is not the only thing that's drowning them. As the plate moves over an upwelling in the mantle — the same thing that's causing the volcanism there — it subsides and cools. I'm sure there are many drowned islands in other extinct and active volcanic provinces and seamount chains: &lt;a href=&quot;https://en.wikipedia.org/wiki/Zubair_Group&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Zubairs&lt;/a&gt;, Canaries, Azores, Iceland, the South Pacific, etc. Sometimes life keeps up for a bit as a coral reef grows around the sinking island, perhaps forming &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4745/are-coral-cays-and-coral-atolls-just-volcanic-islands&quot;&gt;an atoll&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Near-sea-level islands&lt;/strong&gt; like atolls abound in places like &lt;a href=&quot;https://www.google.ca/maps/place/4%C2%B025&amp;#39;39.7%22N+73%C2%B030&amp;#39;34.1%22E/@4.427704,73.509485,67354m/data=!3m1!1e3!4m2!3m1!1s0x0:0x0&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Maldives&lt;/a&gt;. These atolls are volcanic and actively subsiding. Sea-level may or may not inundate them, depending on whether the coral growth can keep up. Another fragile island is &lt;a href=&quot;https://en.wikipedia.org/wiki/Sable_Island&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sable Island&lt;/a&gt; off Nova Scotia — clinging to the edge of the continental shelf.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Volcanos can explode&lt;/strong&gt; as well as sink slowly into the sea. &lt;a href=&quot;https://en.wikipedia.org/wiki/1883_eruption_of_Krakatoa&quot; rel=&quot;nofollow noreferrer&quot;&gt;Krakatau Island&lt;/a&gt; is probably the best example. This one has nothing to do with sea-level.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Rift basins&lt;/strong&gt; start as mountainous tears in the crust, then subside and flood. Global sea-level change will often act to accelerate this. An example might be the various island groups on the shores of the Red Sea. These will likely sink into the sea eventually.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Salt-domes in Louisiana&lt;/strong&gt; (e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Avery_Island,_Louisiana&quot; rel=&quot;nofollow noreferrer&quot;&gt;Avery Island&lt;/a&gt;) form hills, but the domes continue offshore for hundreds of kilometres. Many of them would have been exposed in the past, some even more recently than the last ice age.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Maybe others can chip in some other scenarios; I'm sure there are dozens.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The point is that sea-level is not the only factor — subsidence, sediment accumulation rate, and erosion also play their rôles. But sea-level always plays some part, and &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2555/are-there-secondary-causes-of-sea-level-change&quot;&gt;can change quickly&lt;/a&gt; relative to the other factors.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-09-20T13:24:54.600" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6569" PostTypeId="2" ParentId="6544" CreationDate="2015-09-20T13:40:04.687" Score="2" Body="&lt;p&gt;I think the naming difference is largely qualitative and even arbitrary in some cases. There are lots of 'islands' that are technically connected to a larger landmass by an isthmus of some sort, which would make them peninsulas technically, and not islands.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you take the definition of a peninsula to be a body of land surrounded by water on three sides, then yes, the island in question could technically be called a peninsula. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Local names of landforms are often linked to cultural or historic influences, just as much as they are to their technical description. There's no 'threshold' of isthmus-width (as far as I'm aware), where once crossed, a peninsula-like island becomes an island-like peninsula . If there was it would be entirely arbitrary.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;As an interesting aside, the Isle of Harris in Scotland is not only not an island (there's an isthmus connecting part of it to a larger landmass) but even the isthmus part is not used to define the limit of the island, which occurs at some seemingly arbitrary point on the larger landmass! (see the map in the link to see what I mean)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Harris,_Scotland&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Harris,_Scotland&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="662" LastActivityDate="2015-09-20T13:40:04.687" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6570" PostTypeId="1" AcceptedAnswerId="6571" CreationDate="2015-09-20T16:26:35.933" Score="2" ViewCount="406" Body="&lt;p&gt;Does anyone know roughly what percentage of fossil fuel power plants around the world are equipped with &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_capture_and_storage&quot; rel=&quot;nofollow&quot;&gt;carbon capture and sequestration (CCS)&lt;/a&gt; technology?&lt;/p&gt;&#xA;" OwnerUserId="3431" LastEditorUserId="64" LastEditDate="2015-09-20T19:40:02.927" LastActivityDate="2015-09-20T20:26:04.230" Title="Percentage of power plants with carbon capture and sequestration (CCS) technology?" Tags="|carbon|" AnswerCount="1" CommentCount="0" ClosedDate="2015-10-02T11:30:16.180" ContentLicense="CC BY-SA 3.0" />
  <row Id="6571" PostTypeId="2" ParentId="6570" CreationDate="2015-09-20T20:26:04.230" Score="5" Body="&lt;p&gt;If you accept &lt;a href=&quot;http://files.gereports.com/wp-content/uploads/2012/11/ge-industrial-internet-vision-paper.pdf&quot; rel=&quot;noreferrer&quot;&gt;GE's estimate&lt;/a&gt; of the number of global fossil fuel power plants ( 17,500 ) and compare it to the number of CCS projects out there ( 22 ), you get roughly 0.1 %. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Global CCS Institute released its &lt;a href=&quot;http://hub.globalccsinstitute.com/sites/default/files/publications/180923/global-status-ccs-2014.pdf&quot; rel=&quot;noreferrer&quot;&gt;2014 annual report&lt;/a&gt;; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The world’s first large-scale carbon capture and storage (CCS) project in the power&#xA;  sector commenced operation in October 2014 at the Boundary Dam power station&#xA;  in Saskatchewan, Canada. Two additional large-scale CCS projects in the power&#xA;  sector – at the Kemper County Energy Facility in Mississippi and the Petra Nova&#xA;  Carbon Capture Project in Texas – are planned to come into operation in 2015 and&#xA;  2016 respectively. Construction is also underway on the world’s first large-scale CCS&#xA;  project in the iron and steel sector, the Abu Dhabi CCS Project in the United Arab&#xA;  Emirates (UAE). These four projects are among the 22 large-scale CCS projects in&#xA;  operation or construction around the world – double the number at the beginning of&#xA;  the decade.  &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastActivityDate="2015-09-20T20:26:04.230" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6572" PostTypeId="1" CreationDate="2015-09-20T21:49:38.777" Score="6" ViewCount="707" Body="&lt;p&gt;If you examine the detailed temperature records that form the basis for our understanding of global warming, there are some strange anomalies (at least from a naive point of view where warming affects everywhere equally).&lt;/p&gt;&#xA;&lt;p&gt;For example, by far the largest temperature increases are confined to winter months in the northern hemisphere. As &lt;a href=&quot;http://clivebest.com/blog/?p=6768&quot; rel=&quot;noreferrer&quot;&gt;one commentator has it&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Winter months in the Northern Hemisphere are responsible for most of the observed land warming in CRUTEM4.  The summer months (June, July, August, September) essentially show no warming at all from 1850 to 1990. Overall,  NH winters have warmed about twice as much as  NH summers.&lt;/p&gt;&#xA;&lt;p&gt;...The same exercise for the southern hemisphere shows very little difference where of course the seasonal months  are inverted.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Is there a sensible explanation of this effect? Is it reproduced, for example, in climate models?&lt;/p&gt;&#xA;" OwnerUserId="3333" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-09-21T06:34:19.080" Title="Why do winter temperatures account for most of the increase in global temperature?" Tags="|climate|climate-change|climate-models|climatology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6573" PostTypeId="2" ParentId="6572" CreationDate="2015-09-20T22:17:57.053" Score="7" Body="&lt;p&gt;Energy balance in the winter is highly dependent on the total amount of area covered by snow or ice.   Snow increases the albedo of the Earth which directs the short-wave radiation from the Sun back to space, stopping it from being absorbed by the Earth.  Winters with minimal snow/ice cover effectively allow more solar radiation to be absorbed by the Earth.   Depending on the winter, the amount of snow cover can be quite different from year to year, which can cause great variability in temperature.   In contrast, summer months generally have more stable temperatures because snow cover is less dynamic during those months, and there is roughly the same total solar radiation absorbed from year to year.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2015-09-21T01:06:49.580" LastActivityDate="2015-09-21T01:06:49.580" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6574" PostTypeId="2" ParentId="6527" CreationDate="2015-09-21T06:21:55.173" Score="12" Body="&lt;p&gt;Latent heat is a factor, but is completely eclipsed by the rate of global warming. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, since 1978 the April (maximum) Arctic sea ice has decreased in volume by about $11,000$ cubic km. The latent heat absorbed by the ice to achieve this is about $3.7(10)^{18}$ Joules. Compare this to the amount of excess heat, which has been absorbed by the oceans, which is about $2.0(10)^{23}$ Joules per decade. That is, some three to four orders of magnitude more heat than the decadal heat required to melt the Arctic ice. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course there are complications of the heat absorbed by land (much less than in the oceans), melting of Greenland and Antarctic ice sheets, and uncertainty over the depth of oceanic warming, due to sparsity of measurements, especially in the southern hemisphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But however you cut the statistics, the latent heat is minuscule compared to the planetary heat imbalance.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="6467" LastEditDate="2018-09-03T16:05:37.623" LastActivityDate="2018-09-03T16:05:37.623" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="6575" PostTypeId="2" ParentId="6572" CreationDate="2015-09-21T06:34:19.080" Score="0" Body="&lt;p&gt;The rate of heat transfer increases with the difference in temperature between two objects. The difference in temperature between the equatorial and other regions is greatest in winter (because of the geometry between the earth and the sun). So it would be surprising only if the increase in local temperatures &lt;em&gt;weren't&lt;/em&gt; biggest during local winter. &lt;/p&gt;&#xA;" OwnerUserId="2639" LastActivityDate="2015-09-21T06:34:19.080" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6576" PostTypeId="2" ParentId="5456" CreationDate="2015-09-21T06:52:56.423" Score="4" Body="&lt;p&gt;Two very different processes! First, if the Earth suddenly stopped rotating then the angular momentum would result in everyone and everything on the Earth's surface being flung sideways at a rate proportional to the distance from the Earth's spin axis. That is, no change at the poles, to 1670 km/hour at the equator. There would also be oceanic tsunami's which would sweep over all but the world's highest mountains. Or would they? The amount of energy required to suddenly halt the Earth's angular momentum is so great that its' dissipation would melt the Earths crust, and vaporize the oceans, so maybe there wouldn't be any oceans to form a tsunami, in which case we would all be caught up in a global cyclone of super-heated steam.&#xA;As for Earth ceasing to revolve around the sun, with no centripetal force to balance gravitational attraction we would simply start upon an accelerating drift towards the sun. However, If we assume that our moon stops orbiting the Earth-moon center of gravity, at the same time as Earth (presumably by the same hypothetical process as envisioned by the questioner), then long before we burn up with increasing proximity to the sun, the moon and Earth would collide, also by gravitational attraction.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-09-21T06:52:56.423" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6577" PostTypeId="2" ParentId="5446" CreationDate="2015-09-21T07:06:24.097" Score="1" Body="&lt;p&gt;There are many determinants of tropical storms. The most important is to have sea surface temperatures of &gt;27 deg C. Obviously, this will increase in extent, though not necessarily in frequency, with global warming, and increased incidence of El-Nino events. Shallow sea, as in the western Pacific, warms up faster than deep sea, as in the eastern Pacific. Hence there are always likely to be more tropical storms in the west Pacific. &#xA;The second determinant is for the air mass to have a 'start-up' rotation, which is a function of latitude. That is, almost no tropical storms at the equator, but many in the tropics, as air masses pick up Coriolis rotation. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-09-21T07:06:24.097" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6579" PostTypeId="2" ParentId="2162" CreationDate="2015-09-21T10:13:31.093" Score="0" Body="&lt;p&gt;&lt;strong&gt;Some comparisons do suggest that historic models do a poor job of simulating observed temperatures&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This picture from a &lt;a href=&quot;http://www.nature.com/nclimate/journal/v3/n9/full/nclimate1972.html?WT.ec_id=NCLIMATE-201309&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nature article&lt;/a&gt; is the clearest analysis that avoids the various obfuscations possible when looking at noisy time series data:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VYfUt.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VYfUt.jpg&quot; alt=&quot;nature chart&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The choice made by these authors is to compare just the average extent of warming over a period rather than the noisy time series. This appears to avoid some of the choices that make the time series comparison so obfuscating and controversial (in fact their results don't disagree much with the ones shown in the previous answer form the IPCC, they just choose a presentation method that emphasises the comparison between models and observations). Their result seems to show that most models really do overestimate the actual amount of warming over recent years. In their words:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Recent observed global warming is significantly less than that simulated by climate models.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In somewhat more detail the authors talk about the statistics like this (my highlights):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The evidence, therefore, &lt;em&gt;indicates that the current generation of climate models (when run as a group, with the CMIP5 prescribed forcings) do not reproduce the observed global warming over the past 20 years, or the slowdown in global warming over the past fifteen years&lt;/em&gt;. This interpretation is supported by statistical tests of the null hypothesis that the observed and model mean trends are equal, assuming that either: (1) the models are exchangeable with each other (that is, the ‘truth plus error’ view); or (2) the models are exchangeable with each other and with the observations (see Supplementary Information). Differences between observed and simulated 20-year trends have p values (Supplementary Information) that drop to close to zero by 1993–2012 under assumption (1) and to 0.04 under assumption (2) (Fig. 2c). Here we note that the smaller the p value is, the stronger the evidence against the null hypothesis. On this basis, the rarity of the 1993–2012 trend difference under assumption (1) is obvious. Under assumption (2), this implies that &lt;em&gt;such an inconsistency is only expected to occur by chance once in 500 years&lt;/em&gt;, if 20-year periods are considered statistically independent. Similar results apply to trends for 1998–2012. In conclusion, we reject the null hypothesis that the observed and model mean trends are equal.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The conclusion is that most models (or, perhaps, most results from the ensemble of models) predict more warming that has actually happened. Whether this is a significant problems for models will become more obvious in the next few years as observational data accumulates. The authors include some caveats:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Other factors that contribute to the discrepancy could include a missing decrease in stratospheric water vapour (whose processes are&#xA;  not well represented in current climate models), errors in aerosol forcing in the CMIP5 models, a bias in the prescribed solar irradiance trend, the possibility that the transient climate sensitivity of the CMIP5 models could be on average too high or a possible unusual episode of internal climate variability not considered above. Ultimately the causes of this inconsistency will only be understood after careful comparison of simulated internal climate variability and climate model forcings with observations from the past two decades, and by waiting to see how global temperature responds over the coming decades.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Other authors have addressed the question using a slightly different and less direct approach. They tend to compare the implied climate sensitivity (crudely: how much warming we expect from a doubling of CO&lt;sub&gt;2&lt;/sub&gt; levels in the short or long term) from observations and models. Several recent papers have shown lower estimates (especially for transient climate response) than the values in climate models (see &lt;a href=&quot;http://link.springer.com/article/10.1007%2Fs00382-014-2342-y#page-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lewis &amp;amp; Curry&lt;/a&gt;; &lt;a href=&quot;https://www.researchgate.net/publication/260740743_Bayesian_estimation_of_climate_sensitivity_based_on_a_simple_climate_model_fitted_to_observations_of_hemispheric_temperatures_and_global_ocean_heat_content&quot; rel=&quot;nofollow noreferrer&quot;&gt;Aldrin et. al.&lt;/a&gt;; &lt;a href=&quot;http://www.iac.ethz.ch/people/knuttir/papers/otto13nat.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Otto et. al.&lt;/a&gt;; &lt;a href=&quot;http://www.earth-syst-dynam.net/5/139/2014/esd-5-139-2014.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Skeie et. al.&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Summary&lt;/strong&gt;&#xA;The question was whether models do a good job of simulating the actual future climate. These results suggest they haven't. But there is plenty of scientific uncertainty about whether that failure is &lt;em&gt;significant&lt;/em&gt;. &lt;/p&gt;&#xA;" OwnerUserId="3333" LastEditorUserId="3333" LastEditDate="2015-10-05T17:28:41.830" LastActivityDate="2015-10-05T17:28:41.830" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="6580" PostTypeId="1" CreationDate="2015-09-21T12:41:30.993" Score="2" ViewCount="37" Body="&lt;p&gt;How long does it take for the plastic/polythene shopping bags marked &lt;strong&gt;biodegradable&lt;/strong&gt; to &lt;em&gt;biodegrade&lt;/em&gt;?&lt;/p&gt;&#xA;" OwnerUserId="4522" LastActivityDate="2015-09-21T12:41:30.993" Title="Biodegradation time for biodegradable shopping bags?" Tags="|environmental-protection|" AnswerCount="0" CommentCount="5" ClosedDate="2015-09-22T16:02:46.580" ContentLicense="CC BY-SA 3.0" />
  <row Id="6581" PostTypeId="2" ParentId="5336" CreationDate="2015-09-21T14:36:41.337" Score="5" Body="&lt;p&gt;The partial release of strain energy makes another major earthquake in the same area less likely - in the near future. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, there is not just a single slip plane between the converging Indian and Tibetan tectonic plates. Rather, the nappes (slabs of rock) are stacked about 12 layers deep, with Tibet over-thrusting India at a low angle. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main Himalayan thrust fault slipped at an average depth of about 8 kilometers. There is still unreleased strain energy accumulating in thrust faults above this level. Geographically, an area 120 kilometers long by 60 kilometers wide slipped three metres southwards and one meter upwards in just over 20 seconds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The adjacent Himalayan regions, east and west, will eventually rupture in more or less similar manner. Bear in mind that the mean rate of tectonic convergence across the Nepalese Himalayas &lt;em&gt;in the vicinity of Kathmandu&lt;/em&gt; is 17.5 +/- 2 mm per year, whereas the overall rate of convergence of the Indian and Tibetan (Eurasian) tectonic plates is between 26 and 36 mm per year. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Kathmandu earthquake locally released 86 years' worth of strain energy, equivalent to 35 mm per year, so is very unlikely to slip that much again for decades to come. But if I was living in north India, west Nepal or Bhutan, I'd be worried. The recent earthquake was magnitude 7.8 according to seismometers on the Indian side, and magnitude 8.1 according to Chinese seismometers (counter-intuitively both could be right). For those parts of the Himalayas that haven't experienced a major quake for centuries the accumulating strain could be phenomenal. For these areas a magnitude 8.5 is plausible. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="28050" LastEditDate="2015-10-09T11:47:32.030" LastActivityDate="2015-10-09T11:47:32.030" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6582" PostTypeId="2" ParentId="2122" CreationDate="2015-09-22T04:25:41.670" Score="3" Body="&lt;p&gt;It's a question of &lt;em&gt;rates&lt;/em&gt; of erosion. All mountains start to erode from the moment that mountain building begins. The erosion stops, or slows down to minuscule amounts when the mountains are protected by a vast thickness of ice, as in Greenland and the Antarctic. As soon as the ice starts to melt, normal rates of erosion will resume. Rates of erosion on extraterrestrial surfaces are usually much slower than on Earth, and of different kinds. Mechanisms include thermal expansion and contraction, wind ablation (if there is any kind of atmosphere), melting, micrometeorite to bolide impacts, rock tides, and differential gravitational effects. No part of the cosmos is totally immune from erosion. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-09-22T04:25:41.670" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6583" PostTypeId="2" ParentId="2122" CreationDate="2015-09-22T05:02:16.877" Score="7" Body="&lt;p&gt;Fresh shield volcanoes that are dome-shaped may be of interest to you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qgI6p.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qgI6p.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shield volcanoes on Venus - The Pancake Domes&lt;br&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/zJYSs.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zJYSs.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shield volcanoes on Earth - The Galapagos Islands&#xA;&lt;a href=&quot;https://i.stack.imgur.com/fxTfY.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fxTfY.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2015-09-22T05:02:16.877" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6584" PostTypeId="1" CreationDate="2015-09-20T20:49:15.457" Score="6" ViewCount="158" Body="&lt;p&gt;Much of the raw data behind the various datasets reporting the average temperature of the world are now available. So it is possible to look for strange patterns in the daily or monthly temperature data. The reported &amp;quot;average temperature of the world&amp;quot; is, ultimately, derived from these datasets by various corrections, normalisations and regional aggregations.&lt;/p&gt;&#xA;&lt;p&gt;Recently I came across a claim that the temperature anomalies are remarkably concentrated geographically. The hypothesis suggested, tentatively, by the author (Clive Best, &lt;a href=&quot;http://clivebest.com/blog/?p=3338&quot; rel=&quot;noreferrer&quot;&gt;blog on topic here&lt;/a&gt;) suggested that this might reflect contamination of the raw data by rapid urbanisation. NB his argument is very different from the idea that US data is corrupted by the urban heat island effect which is addressed here: &lt;a href=&quot;https://skeptics.stackexchange.com/questions/10341/has-the-urban-heat-island-effect-on-the-us-temperature-record-been-underestimate&quot;&gt;https://skeptics.stackexchange.com/questions/10341/has-the-urban-heat-island-effect-on-the-us-temperature-record-been-underestimate&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;He reports (my emphasis):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The anomalies from ~4000 stations all over the globe are then combined to give one  global anomaly, yielding  the familiar graph we know and love which shows ~0.6 deg.C rise since 1850. Looking in more detail however we discover that &lt;em&gt;some parts of the world are not warming at all and some  are  even cooling.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;His argument develops:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;It immediately becomes obvious  that  the bulk of  observed warming is concentrated in the Northern Hemisphere : Eastern Europe, Russia, central Asia, India, China, Japan, Middle East, North Africa. These are all areas of rapid population increase, development and industrialisation. There is essentially no warming at all in the Southern Hemisphere. Bolivia, Peru, Paraguay and Argentina all appear to be cooling. Even Australia and Zealand are static or  cooling. The US is evenly divided and the UK shows essentially no signal at all.&lt;/p&gt;&#xA;&lt;p&gt;...Could much of the observed temperature rise over  the last 6 decades  be simply due to increasing urbanisation and development since ~1960 ?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Climate models don't produce even warming across the world so there could be explanations perfectly consistent with the observations of major regional differences. So my question is: does the large variation in regional temperature anomalies have a straightforward explanation in mainstream warming theory or is it a sign that some regional records are contaminated by urban development?&lt;/p&gt;&#xA;&lt;p&gt;NB Best used the data from &lt;a href=&quot;http://www.metoffice.gov.uk/research/climate/climate-monitoring/land-and-atmosphere/surface-station-records&quot; rel=&quot;noreferrer&quot;&gt;HADCRUT3&lt;/a&gt; released by the UK Met Office, but it is also obvious in the NOAA GSOD dataset which is conveniently available to 2010 in Google's BigQuery as a &lt;a href=&quot;https://cloud.google.com/bigquery/sample-tables&quot; rel=&quot;noreferrer&quot;&gt;sample dataset&lt;/a&gt; (you can also download it if you have the capacity process it).&lt;/p&gt;&#xA;" OwnerUserId="3333" OwnerDisplayName="matt_black" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-09-22T09:23:38.237" Title="Does the regional localisation of global temperature trends suggest contamination by urban development?" Tags="|climate-change|climatology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6585" PostTypeId="2" ParentId="6584" CreationDate="2015-09-22T07:20:19.933" Score="5" Body="&lt;p&gt;The blog article suggests that the increase in &quot;waste heat&quot; from growing urbanisation is biasing the temperature observations.  The problem with this argument is that the heat generated directly from burning fossil fuels is far too small to make a difference, compared to the change in the Earths energy balance due to increasing greenhouse gasses.  See: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Integrating anthropogenic heat flux with global climate models Authors&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Mark G. Flanner&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Atmospheric Science, Volume 36, Issue 2, January 2009. &#xA;  DOI:&lt;a href=&quot;http://dx.doi.org/10.1029/2008GL036465&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.1029/2008GL036465&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Abstract &lt;a href=&quot;http://dx.doi.org/10.1029/2008GL036465&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt; Nearly all energy used for human purposes is dissipated&#xA;  as heat within Earth's land–atmosphere system. Thermal energy released&#xA;  from non-renewable sources is therefore a climate forcing term.&#xA;  Averaged globally, this forcing is only +0.028 W m−2, but over the&#xA;  continental United States and western Europe, it is +0.39 and +0.68 W&#xA;  m−2, respectively. Here, present and future global inventories of&#xA;  anthropogenic heat flux (AHF) are developed, and parameterizations&#xA;  derived for seasonal and diurnal flux cycles. Equilibrium climate&#xA;  experiments show statistically-significant continental-scale surface&#xA;  warming (0.4–0.9°C) produced by one 2100 AHF scenario, but not by&#xA;  current or 2040 estimates. However, significant increases in&#xA;  annual-mean temperature and planetary boundary layer (PBL) height&#xA;  occur over gridcells where present-day AHF exceeds 3.0 W m−2. PBL&#xA;  expansion leads to a slight, but significant increase in atmospheric&#xA;  residence time of aerosols emitted from large-AHF regions. Hence, AHF&#xA;  may influence regional climate projections and contemporary&#xA;  chemistry-climate studies.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The blog article says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;My guess is that 80% of this energy ends up as heat (2nd law&#xA;  thermodynamics). Assuming that  energy consumption is concentrated&#xA;  mostly in urban areas then the net “anthropogenic”  heating in those&#xA;  areas works out at around 5 watts/m2. This  then leads to  an average&#xA;  1.4 degreeC. rise in temperature for urban areas.  Anyone who has lived in the city knows from experience that the surrounding&#xA;  countryside is indeed  some 1-2 degrees colder.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Indeed the climatologists know that as well, they are not stupid, and hence &quot;homogenise&quot; the observations to remove these sorts of biases.  Note that if the bias were due to increasing urbanisation, this would be easily detectable by comparison with the observations from rural stations in the same region.  This is not rocket science (see my answer &lt;a href=&quot;https://skeptics.stackexchange.com/questions/22086/does-unadjusted-nasa-climate-data-show-no-long-term-global-warming/22088#22088&quot;&gt;here&lt;/a&gt; for links on homogenization)!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note also that increasing urbanisation would not necessarily cause an increase in local forcing, because as you increase the fossil fuel use, you also increase the area over which it is dissapated, which the author of the blog post also appears to have missed.&lt;/p&gt;&#xA;" OwnerUserId="624" OwnerDisplayName="Dikran Marsupial" LastEditorUserId="-1" LastEditDate="2017-04-13T12:46:45.430" LastActivityDate="2015-09-22T07:30:03.840" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6587" PostTypeId="1" CreationDate="2015-09-23T03:28:09.757" Score="6" ViewCount="153" Body="&lt;p&gt;This evening in Boston there was quite a spectacular sunset. However, many people noticed this odd vertical &quot;stripe&quot; in the west. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has anyone seen this before? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It &lt;em&gt;looked&lt;/em&gt; as though it was projected on the clouds from somewhere near where I was standing (as though a reflection of the sun). This would make sense (the city of Boston, with it's tall glass towers, was right next to us), but could the reflection really reach so far and be described so clearly on the clouds? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NDerE.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NDerE.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4530" LastActivityDate="2015-09-23T07:44:01.800" Title="Unusual light at sunset?" Tags="|meteorology|clouds|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6588" PostTypeId="2" ParentId="6587" CreationDate="2015-09-23T07:44:01.800" Score="3" Body="&lt;p&gt;What you saw was a &lt;a href=&quot;http://www.atoptics.co.uk/atoptics/ray1.htm&quot; rel=&quot;nofollow&quot;&gt;crepuscular ray&lt;/a&gt;. They occur when the Sun's rays stream through gaps in clouds. Such rays tend to appear as parallel columns.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you look closely at the picture you took, there is a subtle angled crepuscular column above the short building near the middle of the picture.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-09-23T07:44:01.800" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6590" PostTypeId="1" CreationDate="2015-09-24T12:18:26.583" Score="1" ViewCount="43" Body="&lt;p&gt;How does hydration increase the lifetime of CaO in &lt;a href=&quot;https://en.wikipedia.org/wiki/Calcium_looping&quot; rel=&quot;nofollow noreferrer&quot;&gt;calcium looping&lt;/a&gt;?&lt;/p&gt;&#xA;" OwnerUserId="3431" LastEditorUserId="595" LastEditDate="2017-12-15T12:04:05.293" LastActivityDate="2017-12-15T12:04:05.293" Title="Effect of hydration on CaO in calcium looping" Tags="|carbon|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6591" PostTypeId="1" AcceptedAnswerId="6592" CreationDate="2015-09-25T01:51:33.010" Score="4" ViewCount="191" Body="&lt;p&gt;As this year's boreal summer monsoon draws to a close interest automatically centers around forecasts for next summer's monsoon and the likelihood of possibly another El Niño event. This brings about the question of historical El Niños and when I googled for the same I came up with this interesting site - &lt;a href=&quot;https://sites.google.com/site/medievalwarmperiod/Home/historic-el-nino-events&quot; rel=&quot;nofollow&quot;&gt;Historical El Niño Events&lt;/a&gt;.&#xA;I am familiar with the European medieval warming period &lt;a href=&quot;https://en.wikipedia.org/wiki/Medieval_Warm_Period&quot; rel=&quot;nofollow&quot;&gt;Medieval Warming Period&lt;/a&gt; but my current question deals with the period from 1790 AD to 1799 AD as mentioned in the first link. It appears apart from the year 1798 all other years were El Niño years and that would appear to be a extraordinary period.&#xA;My question is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Are there any references from paleoclimatology that talk of the atmosphere during that period ? Are those confirmed El Niño events ?&lt;/strong&gt; &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2015-10-02T08:17:38.547" LastActivityDate="2015-10-02T08:25:03.207" Title="Confirmation of historical El Niño events" Tags="|atmosphere|climate|paleoclimatology|enso|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6592" PostTypeId="2" ParentId="6591" CreationDate="2015-09-25T04:00:57.367" Score="3" Body="&lt;p&gt;The best article about the 1789-1793 El Niño is probably &lt;a href=&quot;http://www.nature.com/nature/journal/v393/n6683/full/393318c0.html&quot; rel=&quot;nofollow&quot;&gt;Grove (1998) Nature&lt;/a&gt; study. There is also a lot more information in &lt;a href=&quot;http://mhj.sagepub.com/content/10/1-2/75.abstract&quot; rel=&quot;nofollow&quot;&gt;Grove's 2007 paper&lt;/a&gt;. In the second paper, he explores the global consequences of the El Niño event (some evidence is mostly circumstantial), which he describes as being quite severe: famine (&quot;By November 1792 over 600,000 deaths were being attributed directly to the prolonged droughts&quot;), revolution (French Revolution), economic hardship...&#xA;He provides rainfall and temperature records and many historical reports as evidence of the conditions.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;While further archival research is needed to more fully characterise the 1789–93 event, the evidence of a strong global impact already indicates that it was one of the most severe El Niños recorded. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In &lt;a href=&quot;http://www.pacificdisaster.net/pdnadmin/data/original/JB_DM581_WHP_2000_ElNino_history_crisis.pdf&quot; rel=&quot;nofollow&quot;&gt;El Nino History and Crisis&lt;/a&gt; Grove talks of the idea of a Mega Niño in relation to the continuous series of El Niño events that occurred during the period 1788-93. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In terms of severity,the Indian droughts of 1788-1793 surpassed anything &#xA;  that  had  occurred  since  the  events  of  1685-88,  and  stand  out  as  having  both an unusually long duration and extraordinarily wide effects,   within and beyond  India. Indian  droughts  that  co-occurred  with  El  Ninos  in  the  interim, in   1701-2,   1707-9,   1737   and   1783,   while   serious,   did   not   approach the ferocity  of  the  years 1685-1687  in  southeast  India and  it  was  not  until  1788— &#xA;  1793  that  a  comparable  series  of  extreme  events  took  place.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="111" LastEditorDisplayName="user1066" LastEditDate="2015-10-02T08:25:03.207" LastActivityDate="2015-10-02T08:25:03.207" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6594" PostTypeId="2" ParentId="6492" CreationDate="2015-09-26T00:23:31.203" Score="5" Body="&lt;p&gt;Braiding will occur in any river where two conditions are met: 1) a very high sediment load must be available, as is usually the case in a peri-glacial or post-glacial environment, and 2) there is an abrupt change from high energy rivers (steep hydraulic gradient) to low energy deposition with flat space on either side of the river. Go for a hike in any glacial or post-glacial mountains and you will see that rock hardness has little to do with sediment availability - there is always more sediment than the river can mobilize at any one time, even in extreme floods. The classic example is the Canterbury Plains on the east side of South Island New Zealand. Braiding is an inherently unstable and transient river configuration.&#xA;Meandering is the river's minimum energy configuration. It is another chaotic process, achieved through helicoidal flow and superelevation on the convex side of a bend. It will occur anywhere the river is laterally unconstrained, and where the rotational kinetic energy, perpendicular to the direction of flow, is a significant fraction of the forward kinetic energy.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-09-26T00:23:31.203" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6595" PostTypeId="2" ParentId="6529" CreationDate="2015-09-26T00:44:35.680" Score="4" Body="&lt;p&gt;As the previous answer made clear, tipping bucket raingauges incur errors related to tip increments, rainfall amount, intensity and duration - all for obvious reasons. Many raingauges, TB and otherwise, have funnel filters to stop clogging from leaves, dead lizards, etc. In the case of small rainfall events the wetting and clogging of the filter can cause huge errors. It's important to note that these errors are separate from, and subordinate to, the errors of wetting, splash, and micro-aeodynamic turbulence. These further errors typically amount to an undercatch of about 7%, or very much greater errors in the case of strong horizontal components of wind velocity. Also, the collection area of the TB raingauge is significant. TB rim diameters range from 10 cm to 50 cm with the former being highly inaccurate. Whatever the design of raingauge / pluviometer, it is best to calibrate it with a ground-level rim set in an anti-splash grid. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-09-26T00:44:35.680" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6596" PostTypeId="1" AcceptedAnswerId="6606" CreationDate="2015-09-26T05:36:58.027" Score="10" ViewCount="477" Body="&lt;p&gt;In many parts of the world there are dry lands below sea level, such as parts of the Netherlands. Since we know that temperature decreases with increasing altitude, does it mean that temperature will increase as we go lower below sea level?&lt;/p&gt;&#xA;" OwnerUserId="461" LastEditorUserId="64" LastEditDate="2015-09-26T18:09:17.903" LastActivityDate="2015-09-27T18:25:39.787" Title="Does lapse rate apply below sea level?" Tags="|meteorology|temperature|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6597" PostTypeId="2" ParentId="6544" CreationDate="2015-09-26T06:21:55.003" Score="2" Body="&lt;p&gt;In a topological sense, if it's connected by an isthmus then it isn't an island. That doesn't mean that it might not be called that - but the answer is a cultural &amp;amp; political one, and hence won't adhere to strict definitions.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2015-09-26T06:21:55.003" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6598" PostTypeId="2" ParentId="5169" CreationDate="2015-09-26T13:18:29.190" Score="2" Body="&lt;p&gt;The maximum one-hour rainfall may be 305 mm in America, or 401 mm in Australia, but it certainly isn't the world record measurement, which is in the region of 450 to 500 mm (based upon the global rainfall intensity envelope). The maximum possible is governed by three factors, namely 1) the precipitable moisture in the air column, which is a non-linear function of temperature, assuming no limiting evaporation upwind, 2) the dynamics of condensation, assuming no limitation on the availability of raindrop nuclei, and 3) the lateral advective delivery of moisture. This means that the maximum rainfall is likely to be on the windward side of a high mountain in a tropical oceanic island.&#xA;We will probably never be able to measure the maximum rainfall because, by its nature, it will be in a very windy exposed site, where it is notoriously difficult if not impossible to measure the rainfall accurately. Also, consider the open area of a rain-gauge funnel, and the probability of that just happening to be in the right place to &lt;em&gt;measure&lt;/em&gt; the maximum rainfall over many square kilometers.&#xA;A good description of the probable maximum precipitation is given by Greiser in:   &lt;a href=&quot;http://www.juergen-grieser.de/extremerain_standalone.pdf&quot; rel=&quot;nofollow&quot;&gt;http://www.juergen-grieser.de/extremerain_standalone.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-09-26T13:18:29.190" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6599" PostTypeId="2" ParentId="5298" CreationDate="2015-09-26T13:40:53.560" Score="3" Body="&lt;p&gt;It &lt;em&gt;is&lt;/em&gt; mammatus. The individual cells &lt;em&gt;are&lt;/em&gt; hanging down, but it just isn't very obvious from your perspective. Nice photo. Usually one doesn't have much time to photograph mammatus because of its inherently unstable condition. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-09-26T13:40:53.560" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6600" PostTypeId="2" ParentId="5276" CreationDate="2015-09-26T13:53:18.660" Score="3" Body="&lt;p&gt;The Dead Sea salt is almost equally Mg-chloride and Na-chloride at about four times normal sea-salt salinity. This combination is extremely hygroscopic whilst, at this ultra low elevation and high temperature, there is very high humidity. People who try to towel themselves dry after swimming in the Dead Sea find that they can't - the salt absorbs atmospheric moisture as fast as they can towel it off. In addition to the chemical characteristics of the salt, at such high concentrations the water vapour pressure at the liquid surface is almost nothing. Therefore, it will require extreme and very prolonged dessiccation to dry out the Dead Sea completely. On the other hand the sea-level still has a long way to drop before it becomes a sort of slushy paste. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-09-26T13:53:18.660" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6601" PostTypeId="2" ParentId="5176" CreationDate="2015-09-26T14:21:43.583" Score="3" Body="&lt;p&gt;Of course, any ultramafic rock will ultimately melt at about 2000 deg C, but long before that there will be some interesting phase transitions, possibly involving serpentine &gt; talc &gt; olivine + orthopyroxene. &#xA;Various subtle changes occur in the rock during its original hydration from peridotite to serpentinite. There is high- and low-temperature serpentinite. Isotopic studies have shown that most exposed serpentinite exposed in outcrop has hydrated at ambient groundwater temperature. Consider what happens. The Ca from the clinopyroxene in the original peridotite ends up as Ca- or Ca-Mg- carbonates, of which much is lost or precipitated elsewhere. The Fe in the original orthopyroxene, clinopyroxene and olivine is either lost from the system or re-precipitates as a mesh-texture of goethite. Cr from the silicate phases is excluded from the serpentine crystal lattice and from the surface of chromite crystals leaving a zoned Magnetite-Chromite structure in previously homogeneous chromite crystals. Since these are inert and refractory, they should survive any subsequent dehydration process. Any Ni will probably survive within the serpentine lattice. Summing up, when the serpentine is metamorphosed and turns back into peridotite, look for zoned chromite, reduced Ca (as clinopyroxene), and either reduced Fe, or Fe as a relict ghost sieve structure. Depending upon local circumstances there may, or may not, be a slight loss of silica during the hydration-dehydration cycle. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-09-26T14:21:43.583" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6602" PostTypeId="2" ParentId="4928" CreationDate="2015-09-26T14:43:44.377" Score="2" Body="&lt;p&gt;Under normal circumstances your suggestion might be correct, but bear in mind that the serpentinization reaction takes place under very negative Eh, and very high pH conditions (pH 12 or more). This abnormal combination is right on the boundary of water-hydrogen stability conditions. In hyperalkaline springs, which result from the reaction water + peridotite = serpentine, there is hardly a free molecule of oxygen left in solution. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-09-26T14:43:44.377" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6603" PostTypeId="1" AcceptedAnswerId="6607" CreationDate="2015-09-26T14:50:35.163" Score="9" ViewCount="147" Body="&lt;p&gt;In 1860 or so, following the tragic wreck of the &lt;em&gt;Royal Charter&lt;/em&gt; with the loss of over 400 lives, storm cones were installed in many UK ports, under the direction of Admiral Fitzroy, head of the government's forerunner of the modern Meteorological Office, to warn mariners of expected gales. My question is, please, are these storm cones still in use?&lt;/p&gt;&#xA;" OwnerUserId="4541" LastActivityDate="2015-09-26T18:38:56.363" Title="Are the storm cones introduced by Robert Fitzroy still in use?" Tags="|weather-forecasting|storms|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6604" PostTypeId="1" CreationDate="2015-09-26T15:22:20.090" Score="1" ViewCount="93" Body="&lt;p&gt;I am from India. Please suggest where to find practice questions for earth science Olympiad? Are papers apart from the 2010,2011 entrance test available?&lt;/p&gt;&#xA;" OwnerUserId="4474" LastEditorUserId="5594" LastEditDate="2017-12-15T08:49:00.873" LastActivityDate="2017-12-15T08:49:00.873" Title="practice papers for IESO" Tags="|meteorology|atmosphere|geology|" AnswerCount="0" CommentCount="1" ClosedDate="2015-09-26T18:16:10.407" ContentLicense="CC BY-SA 3.0" />
  <row Id="6605" PostTypeId="2" ParentId="6596" CreationDate="2015-09-26T17:08:19.300" Score="5" Body="&lt;p&gt;The wet and dry adiabatic lapse rates apply regardless of whether or not the altitude in question is below sea level. The Dead Sea is 413 meters below sea level. The dry adiabatic lapse rate is 1°C/100m, so a parcel of air moving from sea level into the Dead Sea area would be expected to heat by just over 4°C, ignoring any possible heating from the change from the dry adiabatic lapse rate to the wet adiabatic lapse rate, which is 0.5°C/100m.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2015-09-26T17:08:19.300" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6606" PostTypeId="2" ParentId="6596" CreationDate="2015-09-26T18:14:40.087" Score="7" Body="&lt;p&gt;Yes.  The height of the ground or ocean surface is of no consequence to the lapse rate as long as we remain above it -- in the atmosphere.  E.g. the dry adiabatic lapse rate is a conservation of entropy as a parcel of air rises or descends.  This means the temperature change is related only to the expansion of contraction of the parcel as it responds to changes in pressure.  When you move down below sea level there is nothing fundementally different than starting at 500 m height and moving down from there.  Both are moving down into higher pressure and the parcel will contract and warm as a result.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2015-09-27T18:25:39.787" LastActivityDate="2015-09-27T18:25:39.787" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6607" PostTypeId="2" ParentId="6603" CreationDate="2015-09-26T18:38:56.363" Score="11" Body="&lt;p&gt;A page in the book &lt;em&gt;&lt;a href=&quot;https://books.google.com/books?id=sxAgCgAAQBAJ&amp;amp;lpg=PT143&amp;amp;ots=Ozu4gOVcAe&amp;amp;dq=fitzroy%20storm%20warning%20cone&amp;amp;pg=PT143#v=onepage&amp;amp;q=fitzroy%20storm%20warning%20cone&amp;amp;f=false&quot;&gt;Come Rain or Shine, A Weather Miscellany&lt;/a&gt;&lt;/em&gt; states that the cones were discontinued on June 1, 1984, due to their being superseded by radio broadcasts and other methods.&lt;/p&gt;&#xA;" OwnerUserId="534" LastActivityDate="2015-09-26T18:38:56.363" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6608" PostTypeId="1" CreationDate="2015-09-26T20:08:53.717" Score="9" ViewCount="152" Body="&lt;p&gt;The transport of tropospheric ozone, ozone precursors, carbon monoxide, etc from Asia to North America is an active area of research (see &lt;a href=&quot;http://www.atmos.washington.edu/jaffegroup/publications/2011AmbroseJaffeHighO3.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;J.L. Ambrose, et al., 2011&lt;/a&gt;)  These types of events occur rather dramatically in the springtime, apparently due to meteorological conditions when westerly winds are strong, which carries polluted air across the Pacific.  Stratospheric ozone events can be differentiated because they have low moisture and no associated increase in carbon monoxide.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What meteorological factors contribute to the increased transport of Asia-generated air pollution to North America? What occurs meteorologically in the springtime that leads to more westerly transport than any other season?  The analyses I've seen say that transport can occur anywhere from 2.5 km to 8 km above sea level.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there factors that could cause temporal or spatial shifts in how these types of pollution transport events are recepted in North America?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mrDUF.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mrDUF.gif&quot; alt=&quot;M. Lin et al., 2011 image&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image from &lt;a href=&quot;http://www.gfdl.noaa.gov/news-app/story.53/title.transport-of-asian-ozone-pollution-into-surface-air-over-the-western-united-states-in-spring/&quot; rel=&quot;nofollow noreferrer&quot;&gt;M. Lin et al., 2011 publication&lt;/a&gt; showing &#xA;carbon monoxide crossing the Pacific Ocean caught by Aqua/AIRS, (10&lt;sup&gt;18&lt;/sup&gt; molecules / cm&lt;sup&gt;2&lt;/sup&gt;)&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="5594" LastEditDate="2017-12-15T08:47:26.343" LastActivityDate="2017-12-15T08:47:26.343" Title="What meteorological factors contribute to springtime Trans-Pacific air-pollution events?" Tags="|meteorology|climate|air-pollution|pacific|" AnswerCount="0" CommentCount="13" ContentLicense="CC BY-SA 3.0" />
  <row Id="6611" PostTypeId="1" CreationDate="2015-09-28T12:50:36.173" Score="8" ViewCount="635" Body="&lt;p&gt;In doing research on the issue of &lt;em&gt;desertification&lt;/em&gt; (aka &lt;em&gt;land degradation&lt;/em&gt;) I keep running across the same basic sentence but no source or detail to support or clarify it:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Arable land loss is estimated to be at 30 to 35 times the &#xA;  historical rate.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Can anyone help me find a source that specifies this &quot;historical rate&quot;? Over what length of time is history being measured? What is the geographic scope of this data?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Failing a specific source for this quote, can anyone provide a reliable source for the data subject the quote refers to (i.e. a long term track record of desertification)?&lt;/p&gt;&#xA;" OwnerUserId="3267" LastEditorUserId="111" LastEditDate="2016-12-18T21:14:32.043" LastActivityDate="2016-12-18T21:14:32.043" Title="Seeking details for the &quot;historical rate&quot; of arable land loss" Tags="|soil|desert|agriculture|history|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="6612" PostTypeId="1" CreationDate="2015-09-28T15:32:17.017" Score="10" ViewCount="1662" Body="&lt;p&gt;While horizontal velocities in the ocean are relatively easy to measure, what methods are available to measure vertical velocities? Is there some indirect way to estimate vertical velocities from observations?&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-10-01T17:39:07.533" Title="How to measure ocean vertical velocity?" Tags="|ocean|oceanography|ocean-currents|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6613" PostTypeId="1" CreationDate="2015-09-28T15:35:03.377" Score="5" ViewCount="642" Body="&lt;p&gt;Modis takes daily images at coarse resolution (500m?) that are then lumped into 16-day composites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;LandSAT, let's say 8, takes roughly bi-weekly images at 30m (100m resampled to 30), and those are then lumped into 32-day composites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clouds aside, would you generally expect the two for the same time period to match?  In other words, if you aggregated the Landsat pixels by mean, ought you to get the same value of the corresponding Modis pixel?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Probably not, right?  Could you explain why?  Is it the 16 vs 32 days?  The world changes in two weeks?  Equipment differences?  Resampling algorithms?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any Modis-LandSAT pairs of data that actually would match quite closely?  &lt;/p&gt;&#xA;" OwnerUserId="2440" LastActivityDate="2015-09-29T07:23:43.453" Title="Should Modis &amp; LandSAT NDVI composites agree and why not?" Tags="|remote-sensing|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6614" PostTypeId="2" ParentId="6612" CreationDate="2015-09-28T17:35:32.617" Score="0" Body="&lt;p&gt;As a non-oceanographer, I might approach this from a continuity standpoint. The sum of the fluxes in each direction must equal 0 (conservation of mass, basically). So you might have some measurements in the x and y directions, which could then give you at least an estimate of the vertical velocities in a given water column, assuming uniform lateral and vertical compositions. There are more assumptions you'd have to make, such as what is a reasonable water column size, that I am not privy too. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;While I wouldn't use this in a scientific paper, I'd bet it would be a good enough initial calculation to see if some question is worth doing a more accurate method. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just an idea... definitely not a definitive answer. &lt;/p&gt;&#xA;" OwnerUserId="32" LastEditorUserId="32" LastEditDate="2015-09-29T18:57:48.143" LastActivityDate="2015-09-29T18:57:48.143" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6617" PostTypeId="2" ParentId="6613" CreationDate="2015-09-29T07:23:43.453" Score="1" Body="&lt;p&gt;I can't comment yet, but I want to share this thought:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One challenge of the comparison is the co-registration of the data, so that really the same area on Earth's surface is compared. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In &lt;a href=&quot;http://www.idrologia.polito.it/~claps/Papers/Boccardo_2006.pdf&quot; rel=&quot;nofollow&quot;&gt;this article&lt;/a&gt; about the difference of MODIS and Landsat 7 NDVI, the authours put much effort in the co-registration to really compare the same area on the ground (but still there was a difference between the two sensors)&lt;/p&gt;&#xA;" OwnerUserId="3289" LastActivityDate="2015-09-29T07:23:43.453" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6618" PostTypeId="1" AcceptedAnswerId="6629" CreationDate="2015-09-29T08:57:05.413" Score="9" ViewCount="352" Body="&lt;p&gt;How favourable were the soil and climate in Russia's landmass of the 1500s for growing crops in comparison with Northern European countries?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3rjLH.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3rjLH.gif&quot; alt=&quot;Russia in 1533&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4552" LastEditorUserId="4552" LastEditDate="2015-09-29T20:57:31.727" LastActivityDate="2016-04-14T14:37:47.060" Title="Was Russia's original territory unfavorable for agriculture?" Tags="|climate|soil|agriculture|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6619" PostTypeId="2" ParentId="6541" CreationDate="2015-09-29T11:45:29.957" Score="1" Body="&lt;p&gt;In January the &lt;a href=&quot;https://en.wikipedia.org/wiki/Intertropical_Convergence_Zone&quot; rel=&quot;nofollow&quot;&gt;Intertropical Convergence Zone&lt;/a&gt; shifts to south of the equator. And the &lt;a href=&quot;https://en.wikipedia.org/wiki/Subtropical_ridge&quot; rel=&quot;nofollow&quot;&gt;Subtropical High Pressure Belt&lt;/a&gt; moves into areas of Venezuela, which leaves it dry. I am guessing this from a study of principles of world geography and climatology; I don't live in Venezuela though.&lt;/p&gt;&#xA;" OwnerUserId="4555" LastEditorUserId="28050" LastEditDate="2015-09-29T13:20:19.243" LastActivityDate="2015-09-29T13:20:19.243" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6620" PostTypeId="1" AcceptedAnswerId="6624" CreationDate="2015-09-30T09:36:18.010" Score="5" ViewCount="172" Body="&lt;p&gt;I've read that when global temperature increases significantly, liquid magma can make it's way closer to the surface of earth, causing increased volcanic activity and earthquakes.  Is there scientific evidence of this?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="543" LastEditDate="2015-10-01T04:00:19.700" LastActivityDate="2015-10-01T09:39:49.997" Title="Do higher global temperatures increase volcanic activity and earthquakes?" Tags="|volcanology|climate-change|earthquakes|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6621" PostTypeId="1" CreationDate="2015-09-30T21:16:56.030" Score="6" ViewCount="403" Body="&lt;p&gt;Given the a mineral assemblage with the minerals $$cp (\ce{CuFeS_2}), bn (\ce{Cu_5FeS_4}), cc (\ce{Cu_2S}), mt (\ce{Fe_3O_4}), py(\ce{FeS_2})$$&#xA;where cp, bn, mt are in contact, and py, cp, bn, cc are in contact.  What are the components? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was told #components=#constituents-#reactions -#constraints but I don't know how to define constituents or constraints.  I'm not sure what the number of reactions is either.  I was trying to define constituents based on oxidation states of the metals (assuming S and O are always -2), and I got $$\ce{Cu^{+1}, Fe^{+4}, Fe^{+3}, Fe^{+2}}$$ where the $$\ce{Fe^{+3}} : cp (\ce{CuFeS_2}), bn (\ce{Cu_5FeS_4})$$ and the  $$\ce{Fe^{+4}}: py(\ce{FeS_2})$$&#xA;and $$\ce{Fe^{+3}, Fe^{+2}}: mt (\ce{Fe_3O_4})$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the number of reactions, I'm confused because only one of the minerals has oxygen (so can't be part of a reaction with one of the others to produce another), and I was having a hard time balancing reactions between the others.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone give me any advice on how to figure out what the components are, and in general how I should define components, constituents, and reactions based on assemblages of minerals?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This question is based on a problem from Walther &quot;Essentials of Geochemistry&quot;&#xA;here is a &lt;a href=&quot;https://books.google.com/books?id=UhW58xSN-T4C&amp;amp;pg=PA144&amp;amp;lpg=PA144&amp;amp;dq=%C2%A0Equilibrium%09%20%20%C2%A0phase%09%20%20%C2%A0assemblages.%09%20%20%C2%A0%09%20%20%C2%A0Consider%09%20%20%C2%A0the%09%20%20%C2%A0vein%09%20%20%C2%A0shown%09%20%20%C2%A0below%09%20%20%C2%A0found%09%20%20%C2%A0in%09%20%20%C2%A0a%09%20%20%C2%A0%20rock%09%20%20%C2%A0from%09%20%20%C2%A0the%09%20%20%C2%A0Hashknife%09%20%20%C2%A0ore%09%20%20%C2%A0deposit&amp;amp;source=bl&amp;amp;ots=IvSxPpTqbU&amp;amp;sig=KP9F1duwc6Is46u5J0v84fImIGw&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0CB4Q6AEwAGoVChMIy_aWnOOfyAIVkH6SCh1AkA_1#v=onepage&amp;amp;q=%C2%A0Equilibrium%09%20%20%C2%A0phase%09%20%20%C2%A0assemblages.%09%20%20%C2%A0%09%20%20%C2%A0Consider%09%20%20%C2%A0the%09%20%20%C2%A0vein%09%20%20%C2%A0shown%09%20%20%C2%A0below%09%20%20%C2%A0found%09%20%20%C2%A0in%09%20%20%C2%A0a%09%20%20%C2%A0%20rock%09%20%20%C2%A0from%09%20%20%C2%A0the%09%20%20%C2%A0Hashknife%09%20%20%C2%A0ore%09%20%20%C2%A0deposit&amp;amp;f=false&quot; rel=&quot;nofollow&quot;&gt;[Link]&lt;/a&gt; to the question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just to clarify based on the given answers, the components are cc, cp, py, and mt?  Since bn is the only one that can be formed from a reactions of the others?&lt;/p&gt;&#xA;" OwnerUserId="4479" LastEditorUserId="64" LastEditDate="2015-10-04T19:19:53.760" LastActivityDate="2015-10-04T19:19:53.760" Title="Define components of mineral assemblage?" Tags="|geochemistry|homework|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6622" PostTypeId="1" AcceptedAnswerId="6623" CreationDate="2015-10-01T07:54:26.060" Score="6" ViewCount="2065" Body="&lt;p&gt;I have a homework question that I'm stuck on, I have attempted interpreting this map but am not sure if I have to correct interpretation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sdnO4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sdnO4.png&quot; alt=&quot;Geological map&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ol&gt;&#xA;  &lt;li&gt;What is the youngest/oldest rock in the geological history of this map?&lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;By law of superposition, oldest: limestone, youngest: mudstone. For this question, I'm used to looking at the law of superposition to determine age but in this diagram the contours don't tell me anything. Did I get these right?&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ol start=&quot;2&quot;&gt;&#xA;  &lt;li&gt;What type of fold is shown on the map?&lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Anticline. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ol start=&quot;3&quot;&gt;&#xA;  &lt;li&gt;Give a brief geological history of map.&lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is the one I need most help in. Magma intrusion at fault lines? Maybe some mudstone intrusion over limestone?.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Again, please tell me if these answers are wrong.&lt;/p&gt;&#xA;" OwnerUserId="4558" LastEditorUserId="725" LastEditDate="2017-03-10T01:07:33.703" LastActivityDate="2017-03-10T01:07:33.703" Title="Interpreting a geological map" Tags="|geology|homework|mapping|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6623" PostTypeId="2" ParentId="6622" CreationDate="2015-10-01T09:33:35.247" Score="6" Body="&lt;h2&gt;1. What is the youngest/oldest rock in the geological history of this map.&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Your approach is the right one but isn't the limestone  underlain by something? Drawing the AB cross section would be of great help here, did you manage to do that?&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;2. What type of fold is shown on the map.&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;What is the definition of a syncline and does your interpretation agree with your answer to question one?&#xA;Are there any legend symbols on the map which would be used to indicate a fold?&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;3. Brief geological history of map&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Putting all the lithologies and the deformation (Question 2) in right order would be a big part of that. After that maybe you have some ideas about a succession of claystone, limestone and mudstone&lt;/p&gt;&#xA;" OwnerUserId="2861" LastEditorUserId="2861" LastEditDate="2015-10-01T09:58:42.327" LastActivityDate="2015-10-01T09:58:42.327" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="6624" PostTypeId="2" ParentId="6620" CreationDate="2015-10-01T09:39:49.997" Score="1" Body="&lt;p&gt;Define 'significant' effect. Yes, in principle, both volcanoes and major fault lines can, in some cases, be affected by higher global temperatures. It works like this: higher temperatures cause glacial melt and thermal expansion of seawater, which causes sea level to rise. In ocean sediments and coastal aquifers this raises the hydrostatic pressure, increasing groundwater circulation, and hence providing more 'lubrication' to fault planes, and increasing the seepage above magma chambers. However, the effect is small. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-01T09:39:49.997" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6625" PostTypeId="2" ParentId="6622" CreationDate="2015-10-01T09:50:59.893" Score="4" Body="&lt;p&gt;From the dips it is obvious that the stratigraphic structure is a syncline, in which case you correctly deduce that the youngest &lt;em&gt;layered&lt;/em&gt; rock is the mudstone. But look carefully. The dips on either side of the fold axis are more than at right angles to each other, indicating an open fold of about a 110 degree deformation. Now consider the basalt dykes: basalt is normally intruded as sheets along planar fractures. It is obvious that these dykes have not been deformed, or they would be curved. Therefore they are post-deformational, and are therefore the youngest rocks on the map.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-01T09:50:59.893" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6627" PostTypeId="2" ParentId="6611" CreationDate="2015-10-01T10:38:35.230" Score="2" Body="&lt;p&gt;No context is given, but at face value this is a meaningless quotation. Globally there is a net &lt;em&gt;increase&lt;/em&gt; in arable land from close to zero about 8000 years ago, to the current maximum of just over 40% of the gross biological productivity of the planet. 'Arable land loss' can refer to the land lost to urbanization, salinization or desertification. One might also make a distinction about agricultural land lost to hydrologic intervention, as in the decreasing flows of the Amu Darya, and Sur Darya in Central Asia. In addition, over the coming decades we will begin to see agricultural land lost to climate change impacts. No single assessment of the 'historical rate' of arable land loss is meaningful. One has to evaluate the various processes separately, and then aggregate them at regional level. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-01T10:38:35.230" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="6629" PostTypeId="2" ParentId="6618" CreationDate="2015-10-01T12:44:15.923" Score="5" Body="&lt;p&gt;The area outlined covers several climatic zones. The northeastern part was, and to some extent still is, permafrost at shallow depth, so obviously this was not good for agriculture. Further south most of the area outlined is covered in podzols, which are generally sandy and nutrient poor. Therefore, where water availability is not a limiting constraint (and we have no rainfall records for the 1500s), and where it is not too cold, the soils could have supported agriculture- but only just. They would most likely not have been high yielding. Even today, such soils need a lot of extra nutrients and additional organic carbon to give good results. Politics apart, maybe this is why much of Russia has remained so poor for so long?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-01T12:44:15.923" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6630" PostTypeId="2" ParentId="6612" CreationDate="2015-10-01T17:39:07.533" Score="7" Body="&lt;p&gt;Direct measurements of three-dimensional ocean currents are carried out with acoustic Doppler current profilers (&lt;a href=&quot;http://www.whoi.edu/instruments/viewInstrument.do?id=819&quot; rel=&quot;noreferrer&quot;&gt;ADCPs&lt;/a&gt;). The ADCPs are usually moored and bottom mounted instead of being ship-based or attached to a floating mooring to minimize the vertical displacement associated with the vertical motions of the ocean surface caused by waves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ADCP does not measure horizontal or vertical velocities at a point but determines Doppler shifts along three to five acoustic beams that are typically slanted (most commonly 60°) from the horizontal plane and spaced around the horizontal compass. The most typical configuration (Janus) includes four orthogonal beans. The Doppler shifts measure slant velocities of suspended acoustic backscattering particles moving with the water relative to the instrument. Pairs of slant velocities are combined to produce vertical and horizontal velocities. The underlying assumption is that velocities are horizontally uniform over the beam separation. Other instruments (e.g., &lt;a href=&quot;http://www.rdinstruments.com/followV.aspx&quot; rel=&quot;noreferrer&quot;&gt;Teledyne Sentinel V ADCP&lt;/a&gt;) have an integrated fifth beam to provide a third vertical velocity measurement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IV4GU.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IV4GU.jpg&quot; alt=&quot;ADCP&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Indirect estimates of vertical velocities can be obtain in several ways. The most common approach is to take advantage of the principle of conservation of mass (&lt;a href=&quot;http://oceanworld.tamu.edu/resources/ocng_textbook/chapter07/chapter07_07.htm&quot; rel=&quot;noreferrer&quot;&gt;continuity equation&lt;/a&gt;, as described in the answer by Neo).&#xA;$$&#xA;\dfrac{\partial w}{\partial z} = -\dfrac{\partial u}{\partial x}-\dfrac{\partial v}{\partial y}&#xA;$$&#xA;where $w$ is the vertical velocity. Assuming $w=0$ at the bottom, then measuring the horizontal velocities throughout the water column will give you an estimate of the vertical velocity. This method, while useful, tend to produce really noisy results as the vertical velocities in the ocean tend to be quite small and are masked by the noise in the horizontal measurements. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A completely different approach was recently introduced by &lt;a href=&quot;http://dx.doi.org/10.1029/2009GL038359&quot; rel=&quot;noreferrer&quot;&gt;Klein et al. (2009)&lt;/a&gt;. It uses the surface Quasi-Geostrophic approximation to estimate low-frequency vertical velocities in scales between 20 km and 400 km from the surface down to 500 m. The needed data is some high-resolution Sea Surface Height (SSH, usually from satellites) and an approximation of the large-scale vertical stratification. Vertical velocities are estimated from the buoyancy equations at the surface and at depth in a modified version of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Omega_equation&quot; rel=&quot;noreferrer&quot;&gt;Omega equation&lt;/a&gt; (&lt;a href=&quot;http://academiccommons.columbia.edu/download/fedora_content/download/ac:151885/CONTENT/qj.49711147002.pdf&quot; rel=&quot;noreferrer&quot;&gt;Hoskins et al., 1985&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-10-01T17:39:07.533" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6631" PostTypeId="1" AcceptedAnswerId="6632" CreationDate="2015-10-01T22:28:13.557" Score="8" ViewCount="1115" Body="&lt;p&gt;When you look at other planets and moons in our solar system most of them have lots of craters. If Earth had no vegetation and water would it also look like this image of Charon?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zbBvs.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zbBvs.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nasa.gov/image-feature/charon-in-enhanced-color&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image Credit: NASA/JHUAPL/SwRI&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4566" LastEditorUserId="725" LastEditDate="2017-03-10T01:19:33.037" LastActivityDate="2017-03-10T01:19:33.037" Title="Are craters on Earth covered by vegetation?" Tags="|plate-tectonics|earth-history|geomorphology|meteorite|erosion|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6632" PostTypeId="2" ParentId="6631" CreationDate="2015-10-02T01:14:08.137" Score="5" Body="&lt;p&gt;Well the oceanic crust get recycled (through subduction), the oldest being only ~200 million year old, and the average, much younger. And on continents it is not just vegetation but dynamic processes such as collision, rifting, erosion etc. that quickly (in geologic time scales) modify the landscape. Even Chicxulub is not obvious if you just look at the topography/bathymetry.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastActivityDate="2015-10-02T01:14:08.137" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6633" PostTypeId="2" ParentId="6631" CreationDate="2015-10-02T01:58:51.137" Score="5" Body="&lt;p&gt;Erosion (especially), viscous relaxation, uplift, crust recycling (in the long term), volcanic activity, filling of the crater with deposits, and distortion by crust deformation (&lt;em&gt;eg&lt;/em&gt; earthquakes) are all more important than vegetation, except for very small craters. Other planets and bodies have few or none of these processes.&lt;/p&gt;&#xA;" OwnerUserId="4487" LastActivityDate="2015-10-02T01:58:51.137" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6634" PostTypeId="2" ParentId="6631" CreationDate="2015-10-02T02:47:09.550" Score="6" Body="&lt;p&gt;Without water there would be no multi-billion year history of plate tectonics, no glacial action, and no fluvial erosion, so the Earth would look unrecognizably primitive. But we have an atmosphere, so all the impact crater rims would be subject to aeolian erosion whilst low points, including crater bowls, would have aeolian sedimentary infill. Volcanic activity would be much more obvious, and would also tend to obliterate craters, as it has in numerous other examples in the solar system. Earth would therefore appear as a rather muted, sediment-draped version of the moon. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-02T02:47:09.550" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6635" PostTypeId="2" ParentId="6621" CreationDate="2015-10-02T11:18:58.813" Score="2" Body="&lt;p&gt;Let's start by understanding what a component is. The components of a system are the minimum amount of chemical 'species' required to describe a system. What does that mean? Let's take a familiar example. Periclase, forsterite, enstatite and quartz. That's MgO, Mg&lt;sub&gt;2&lt;/sub&gt;SiO&lt;sub&gt;4&lt;/sub&gt;, MgSiO&lt;sub&gt;3&lt;/sub&gt; and SiO&lt;sub&gt;2&lt;/sub&gt;. So we can say we have 4 components, each of those formulas I just noted. But that's not the minimum number. We can get a smaller number. So we can say, for example that our components are Mg, Si and O. We can create all of the mineral formulas from those 3 components. But wait - we can go even lower! If we choose our components to be only MgO and SiO&lt;sub&gt;2&lt;/sub&gt;, we have 2 components that can still describe our entire system. We can combine 2MgO+1SiO&lt;sub&gt;2&lt;/sub&gt; to describe forsterite and 1MgO+1SiO&lt;sub&gt;2&lt;/sub&gt; to describe enstatite. Basically, the components have to be independent. If there is one component that can be described by others, then it is not actually a component.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So let's go to your problem. First of all, I would say that your assumption that the oxidation state of Cu is +1 and that of S is -2 is not entirely correct. In pyrite, S is actually -1 and Fe is +2 (Fe&lt;sup&gt;4+&lt;/sup&gt; does not exist). As an aside, the oxidation state of Cu (and others) in sulfides is a can of worms: those are not ionic compounds but rather a mixture of metallic and covalent compounds where oxidation state does not mean much, especially in the more complex cases such as bornite and chalcopyrite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, if you look carefully and try to balance your reactions (try to make one mineral using the others), you can see that bn = cp + 2cc, so bn is not a component. Can you still reduce the amount of components? No. Fe&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt; must be there, and there is no way you can make CuFeS&lt;sub&gt;2&lt;/sub&gt; from Cu&lt;sub&gt;2&lt;/sub&gt;S and FeS&lt;sub&gt;2&lt;/sub&gt;. You might think about using the components S-Fe-Cu-O, but that would actually be incorrect because for that to happen S has to be the same valence, which obviously is not (compare Cu&lt;sub&gt;2&lt;/sub&gt;S&lt;sup&gt;2-&lt;/sup&gt; and FeS&lt;sup&gt;1-&lt;/sup&gt;&lt;sub&gt;2&lt;/sub&gt;).&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-10-02T11:18:58.813" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6636" PostTypeId="2" ParentId="6491" CreationDate="2015-10-02T11:27:18.837" Score="3" Body="&lt;p&gt;Yes, two or even more rarely, three tropical storms or hurricanes / typhoons can merge, and have done so in nearly all the major ocean basins where sea surface temperatures exceed 27 deg C. As far as I know this has never been observed in the South Atlantic (can anyone confirm this?). The result of a tropical storm merger is initially determined by 'conservation of angular momentum'. As the storm progresses, it either weakens or strengthens in the usual way, That is, according to (a) the available latent heat of evaporation, which in turn is a function of sea surface temperature beneath the storm footprint, and (b) whether kinetic energy is dissipated as friction over land.  &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-02T11:27:18.837" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6640" PostTypeId="2" ParentId="5357" CreationDate="2015-10-02T14:15:22.217" Score="6" Body="&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Go to a good geological museum and spend time there. Alas, many&#xA;such museums have dumbed down, and are not as informative as they&#xA;used to be (Natural History Museum in Kensington, London - I'm&#xA;writing about you!).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Go walkabout with local rockhound / geology clubs. There are&#xA;always geologists trying to impress with their knowledge.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Get a geological map of a complex area, and explore. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Do a course in geology.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Books, even with good illustrations, usually fail; to point out the salient features and variability. Do not expect to learn it all. I have been a geologist for more than 40 years, and have checked out the geology in about 45 countries. I'm still learning! There is always something new to see. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="725" LastEditDate="2017-03-25T12:25:15.173" LastActivityDate="2017-03-25T12:25:15.173" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6641" PostTypeId="1" CreationDate="2015-10-03T00:18:56.060" Score="7" ViewCount="76" Body="&lt;p&gt;Does anybody know if it is necessary to apply corrections to the reading given by this logging tool? Corrections such as bed thickness, borehole diameter, invasion, etc.? If so, is there anywhere I can find such charts (or formulas) in order to correct the value given by the tool?&lt;/p&gt;&#xA;" OwnerUserId="3259" LastEditorUserId="28050" LastEditDate="2015-10-03T19:26:55.143" LastActivityDate="2015-10-03T19:26:55.143" Title="High-resolution laterolog array tool" Tags="|geophysics|geology|measurements|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6642" PostTypeId="1" AcceptedAnswerId="6644" CreationDate="2015-10-03T00:41:02.670" Score="2" ViewCount="166" Body="&lt;p&gt;What causes cold temperatures to move earlier than they usually move? Here in Buffalo the weather was 9 &amp;deg;C. However, everyone had winter coats and hats on. There was no snow, but it was very very cold. I have a feeling that the Great Lakes may have something to do with it.&lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="111" LastEditDate="2016-07-05T02:45:33.307" LastActivityDate="2016-07-05T18:52:13.627" Title="Global warming and winter temperatures" Tags="|meteorology|climate-change|weather-forecasting|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6643" PostTypeId="1" CreationDate="2015-10-03T02:31:13.923" Score="3" ViewCount="156" Body="&lt;p&gt;If the &lt;a href=&quot;http://www.weather.gov/&quot; rel=&quot;nofollow&quot;&gt;National Weather Service&lt;/a&gt; website shows increasing probability of precipitation (POP) over a 6 hour period (e.g. 10% rising gradually to 60%), what is the POP in this time interval if the confidence percentage is unknown?&lt;/p&gt;&#xA;" OwnerUserId="4571" LastEditorUserId="725" LastEditDate="2017-05-14T03:45:58.950" LastActivityDate="2017-05-14T03:45:58.950" Title="How to calculate hourly rainfall projections?" Tags="|meteorology|precipitation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6644" PostTypeId="2" ParentId="6642" CreationDate="2015-10-03T13:47:49.283" Score="1" Body="&lt;p&gt;The Great Lakes contribute to a huge thermal inertia, which will even out short-term temperature fluctuations, and delay the smoothed seasonal temperature peak. On the other hand, more sinuous looping of the jet stream  is likely to have a comparable, if not larger, effect upon the temperatures in Buffalo. The process is this: As global warming progresses there is a disproportionate warming towards the polar regions. This results in a reduced temperature gradient with respect to latitude. It is this gradient which is largely responsible for the jet stream intensity. As the jet stream weakens it becomes more sluggish and sinuous, resulting in regional hot and cold anomalies. If Buffalo happens to get caught in one of these jet stream loops, it is quite possible to have periods of anomalously low temperature, even though there is an overall North American warming. It is also possible for Buffalo to get caught in a negative loop, and hence experience anomalously hot temperatures. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-03T13:47:49.283" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6645" PostTypeId="2" ParentId="6643" CreationDate="2015-10-03T14:04:09.037" Score="3" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Probability_of_precipitation&quot; rel=&quot;nofollow&quot;&gt;Probability Of Precipitation&lt;/a&gt; or POP is the exceedance probability over a given area for a given duration. The exceedance amount is generally taken as 0.25 mm, but may be any specified value. Again, the time $t$ must be specified, and is usually 3, 6, 12 or 24 hours.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Strictly speaking, the POP is meaningless unless the area under consideration is also specified, although in public weather forecasts this is seldom indicated. Individual storm cells generally have a footprint only a few kilometers wide, so obviously, the larger the area the higher the probability of precipitation, but the lower the average rainfall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the confidence, this is a function of rainfall record duration and continuity, and raingauge network density. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="28050" LastEditDate="2015-10-09T11:55:44.633" LastActivityDate="2015-10-09T11:55:44.633" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6646" PostTypeId="1" AcceptedAnswerId="6647" CreationDate="2015-10-03T14:54:33.660" Score="6" ViewCount="8622" Body="&lt;p&gt;I am looking for some geological data where presenting it in a rose diagram is desirable. I don't really know what kind of data is suitable. Any suggestion of data — preferably from the field of stratigraphy or petrology (igneous, sedimentary, metamorphic) — would be useful. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also are there any good reference book on rose diagrams? Thank you.&lt;/p&gt;&#xA;" OwnerUserId="4574" LastEditorUserId="28050" LastEditDate="2015-10-03T17:25:20.587" LastActivityDate="2018-01-18T18:47:24.880" Title="What kind of data is best shown in a rose diagram?" Tags="|geology|open-data|statistics|reference-request|visualization|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6647" PostTypeId="2" ParentId="6646" CreationDate="2015-10-03T17:41:50.677" Score="7" Body="&lt;p&gt;&lt;strong&gt;Rose diagrams, also called polar bar plots, are useful for showing azimuthal (directional) data. Any dataset consisting of lots of measurements of direction or orientation could be visualized this way.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A common application in sedimentology is visualizing measured cross-bedding azimuths. This can help work out the palaeocurrent direction (that is, the direction of the prevailing wind or current at the time). &lt;a href=&quot;http://www.pstat.ucsb.edu/faculty/jammalam/html/Some%20Publications/1966_CrossbeddingAzimuths-%20Sankhya.pdf&quot; rel=&quot;noreferrer&quot;&gt;This paper by Sengupta and Rao&lt;/a&gt; has some examples and some data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rose diagram display is also often used by structual geologists, to visualize the measured orientations of folds, faults, or other strain indicators. &lt;a href=&quot;https://www.wou.edu/las/physci/taylor/es406_structure/TM_chap2_Techniques.pdf&quot; rel=&quot;noreferrer&quot;&gt;Here's an example&lt;/a&gt; (on page 10 of the PDF) from &lt;a href=&quot;https://books.google.ca/books/about/Structural_Geology.html?id=14fn03iJ2r8C&quot; rel=&quot;noreferrer&quot;&gt;Twiss &amp;amp; Moores's &lt;em&gt;Structural Geology&lt;/em&gt; book&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One way to generate a lot of data yourself would be to find a geological map with lots of faults or dip/strike indicators on it, and then measure their angles (clockwise from N). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not sure which came first, but I suspect the design was originally conceived &lt;a href=&quot;https://en.wikipedia.org/wiki/Wind_rose&quot; rel=&quot;noreferrer&quot;&gt;for wind data&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-10-03T17:41:50.677" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6649" PostTypeId="2" ParentId="6631" CreationDate="2015-10-03T21:58:48.457" Score="6" Body="&lt;p&gt;&lt;strong&gt;No, there are nowhere near this many craters on earth.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think you're asking if there are lots of craters on earth too, but they're hard to see because of vegetation and the oceans. The answer is 'no'. The main reason is that — thanks to &lt;a href=&quot;https://en.wikipedia.org/wiki/Plate_tectonics&quot; rel=&quot;nofollow noreferrer&quot;&gt;plate tectonics&lt;/a&gt; — most of the crust is substantially younger (hundreds of millions of years) than the surface of, say, the moon (billions of years):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/P78kn.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/P78kn.jpg&quot; alt=&quot;The age of continental crust&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ocean floor is mostly less than 200 Ma old:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/f/f5/Earth_seafloor_crust_age_1996_-_2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/f/f5/Earth_seafloor_crust_age_1996_-_2.png&quot; alt=&quot;The age of oceanic crust&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This can account for even more of the difference than you might think, because it's thought that bolide impacts were several orders of magnitude more frequent a billion years ago than they are today. There was a lot of detritus in the early solar system!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We also see this surface age effect &lt;a href=&quot;http://www.esa.int/spaceinimages/Images/2006/05/Highlands_and_mare_seen_by_SMART-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;on the moon&lt;/a&gt; itself: the mare (seas) are made of relatively young lava, and have many fewer craters than the older highlands:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vtzRI.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vtzRI.jpg&quot; alt=&quot;Lunar Highlands compared to Mare&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other than the age of the planet's surface, there are some secondary reasons why there are fewer craters on earth:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The earth has an atmosphere, in which most particles — things that might make a crater on a planetoid without an atmosphere — break or burn up.&lt;/li&gt;&#xA;&lt;li&gt;The earth has water and weather, resulting in glaciers, frost, rain, and so on — this all acts to erase surface features through &lt;a href=&quot;https://en.wikipedia.org/wiki/Erosion&quot; rel=&quot;nofollow noreferrer&quot;&gt;erosion&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;This is not to say that things don't hit earth — they do, all the time. Just look at this map of recorded bolides over a recent 20 year period (Planetary Science, NASA, &lt;a href=&quot;http://www.universetoday.com/116355/we-are-not-alone-government-sensors-shed-new-light-on-asteroid-hazards/&quot; rel=&quot;nofollow noreferrer&quot;&gt;via Universe Today&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gHABW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gHABW.jpg&quot; alt=&quot;Recent bolides&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2015-10-04T00:23:55.360" LastActivityDate="2015-10-04T00:23:55.360" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6650" PostTypeId="2" ParentId="6507" CreationDate="2015-10-03T22:05:09.723" Score="5" Body="&lt;p&gt;There are several approaches to answer this question. One is simple, but not that accurate. This approach would be to to discretize points along the perimeter and calculate a per point boundary shear stress. The equation would be the same as the depth averaged, except you would solve for each individual depth h1, ..., hn.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/YLuup.png&quot; alt=&quot;1&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing to note is that the bed load will mostly be concentrated at the lowest point in the channel.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The easiest accurate method to implement is the WTA method, which uses the law of the wall to calculate boundary shear stress. The papers outlining the method are Wobus et al. (&lt;a href=&quot;http://dx.doi.org/10.1029/2006GL027182&quot; rel=&quot;nofollow noreferrer&quot;&gt;2006&lt;/a&gt;, &lt;a href=&quot;http://dx.doi.org/10.1029/2007JF000914&quot; rel=&quot;nofollow noreferrer&quot;&gt;2008&lt;/a&gt;) titled &quot;Self-formed bedrock channels&quot;&lt;a href=&quot;http://dx.doi.org/10.1029/2006GL027182&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;sup&gt;[1]&lt;/sup&gt;&lt;/a&gt;, and &quot;Modeling the evolution of channel shape: Balancing computational efficiency with hydraulic fidelity&quot; &lt;a href=&quot;http://dx.doi.org/10.1029/2007JF000914&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;sup&gt;[2]&lt;/sup&gt;&lt;/a&gt;. I have a python code that implements this, but in closed conduit conditions. It can be modified to work in the open channel case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Wobus et al., 2006: &lt;em&gt;Self-formed bedrock channels&lt;/em&gt;. doi: &lt;a href=&quot;http://dx.doi.org/10.1029/2006GL027182&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.1029/2006GL027182&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Wobus et al., 2008: &lt;em&gt;Modeling the evolution of channel shape: Balancing computational efficiency with hydraulic fidelity&lt;/em&gt;. doi: &lt;a href=&quot;http://dx.doi.org/10.1029/2007JF000914&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.1029/2007JF000914&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="4576" LastEditorUserId="5594" LastEditDate="2018-03-14T11:08:55.323" LastActivityDate="2018-03-14T11:08:55.323" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6651" PostTypeId="1" CreationDate="2015-10-04T06:19:34.320" Score="6" ViewCount="1986" Body="&lt;p&gt;I'm having trouble determining the type of fault represented on this map.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DDooW.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DDooW.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;What type of fault is represented on this map?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;What is the fault orientation?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;What does this mean?, Do I do this by working out strike/dip angle/dip direction of the line F–F'?. In the example I did in class, I was given the orientation every time and just drew the cross sections, so I don't know.&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;determine components of fault movement, i.e., work out dip-slip, strike-slip, net-slip, heave and throw&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I know the formulas for each or how to determine some, but where do I have to start on this map? From what I can see I can maybe work out the throw first?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Throw = displacement of horizontal feature = 100 m?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Heave - slide said to use trigonometry&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can't find any examples online for the maths of faults and so I think I need a lot of help with this part if someone could work step by step. Because when I look at this map, I don't know where to start and where things are going by calculating those things. Thanks&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I did a rough cross section of the map, but I don't know the orientation of the fault so I just assumed it was in that direction.&lt;/p&gt;&#xA;" OwnerUserId="4558" LastEditorUserId="725" LastEditDate="2017-03-10T01:09:44.280" LastActivityDate="2017-12-15T08:42:58.210" Title="Maps and Faults" Tags="|geology|homework|mapping|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6652" PostTypeId="1" CreationDate="2015-10-04T13:08:38.573" Score="6" ViewCount="1268" Body="&lt;p&gt;I'm trying to figure out how to plot the stability of 4 minerals — $\ce{CaCO3}$, $\ce{CaSO4}$, $\ce{CaMg(CO3)2}$, and $\ce{CaMg3(CO3)4}$ — with axes of $\mathrm{ln}\,a_{\ce{Mg^{+2}}}$ vs $\mathrm{ln}\,a_{\ce{SO_4^{-2}}}$  where $\mathrm{ln}\,a$ is the natural log of the activities of each ionic species. The activity of carbonate is a given.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found solubility $K$ for each dissolution, based on the Gibbs free energy, $R$, and $T = 25^\circ \mathrm{C}$, then tried to set up equations to plot the following:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;$\mathrm{ln}\,K_{\ce{sp,\,CaCO3}} = \mathrm{ln}\,a_{\ce{Ca}} + \mathrm{ln}\,a_{\ce{CO_3}}$&lt;/li&gt;&#xA;&lt;li&gt;$\mathrm{ln}\,K_{\ce{sp,\,CaSO4}} = \mathrm{ln}\,a_{\ce{Ca}} + \mathrm{ln}\,a_{\ce{SO_4}}$&lt;/li&gt;&#xA;&lt;li&gt;$\mathrm{ln}\,K_{\ce{sp,\,CaMg(CO_3)_2}} = \mathrm{ln}\,a_{\ce{Ca}} + \mathrm{ln}\,a_{\ce{Mg}} + 2\,\mathrm{ln}\,a_{\ce{CO_3}}$&lt;/li&gt;&#xA;&lt;li&gt;$\mathrm{ln}\,K_{\ce{sp,\,CaMg_3(CO_3)_4}} = \mathrm{ln}\,a_{\ce{Ca}} + 3\,\mathrm{ln}\,a_{\ce{Mg}} + 4\,\mathrm{ln}\,a_{\ce{CO_3}}$&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Based on the thermo data each $\mathrm{ln}\,K$ is a constant (since $T$, $P$ are constant), since the activity of carbonate is given it seems like I should be able to solve equation 1 for the activity of calcium, but then each equation is a point not a line.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm confused as to how each of the equations is dependent on $\ce{SO_4}$ at all (which is supposed to be my y axis), and how to relate everything. I tried to treat activity $\ce{Ca}$ as variable, then solve for it in terms of activity $\ce{SO_4}$, to then make equations 3, 4 dependent on $\ce{SO_4}$, and $\ce{Mg}$, but then I had no idea how to treat equations 1 and 2. Also the values I got for that were really big, the lines were on $y=35+3x$ and $y=18+x$.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This question is based on a question for a textbook, which I'm trying to use to study for an upcoming exam (1 week), so any help would be greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="4479" LastEditorUserId="4487" LastEditDate="2015-10-25T15:21:20.720" LastActivityDate="2015-10-25T15:21:20.720" Title="Plotting a mineral stability diagram" Tags="|geochemistry|homework|minerals|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6653" PostTypeId="1" CreationDate="2015-10-04T19:37:02.253" Score="13" ViewCount="1458" Body="&lt;p&gt;As far as I understand, we are currently living in the Holocene, an interglacial period of the Quaternary glaciation, i.e. the current ice age that has so far lasted 2.6 million years. The Holocene began about 12,000 years ago. While humans emerged about 200,000 years ago, human civilization is almost entirely coterminous with the Holocene.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Questions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(A) Are there any generally accepted estimates for how long the Holocene will last?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(B) Is anthropogenic global warming delaying the return to glaciation? &lt;/p&gt;&#xA;" OwnerUserId="4579" LastEditorUserId="11908" LastEditDate="2019-03-14T00:58:58.323" LastActivityDate="2019-03-14T00:58:58.323" Title="When will glaciation resume? Has global warming delayed return to global cooling?" Tags="|climate-change|climate|glaciology|ice-age|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6654" PostTypeId="2" ParentId="6653" CreationDate="2015-10-05T08:17:55.687" Score="-2" Body="&lt;p&gt;A) Some would argue that the Holocene is over, and we are now entering the 'Anthropocene', a new era hugely impacted by human activities. Another view is that the Holocene will be over when the polar (including Greenland) ice reaches a new equilibrium state - which is not in the foreseeable future.  Technically there is no way to predict the 'official' end of the Holocene. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;B) Major glaciations are somewhat infrequent in the history of planet Earth. There have only been about 7 +/-1 glaciations, depending upon how you define 'major'. The current glaciation is about over, and human induced global warming will see to it that we are not just entering a mere inter-glacial interlude. On top of human induced global warming there is another very long-term global warming caused by the sun's changing radiance. Since the mid pre-Cambrian the sun's composition has changed from less hydrogen to more helium, which has increased the sun's energy output by about 20 to 25%. This change will continue at a slow but accelerating rate, such that the the planet is getting progressively warmer, and we will never again see another major glaciation on planet Earth. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-05T08:17:55.687" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="6655" PostTypeId="2" ParentId="6651" CreationDate="2015-10-05T08:40:15.177" Score="5" Body="&lt;p&gt;There are no dips given, so you have to work by pure geometric deduction. The sediment subcrops on the east side all seem to be roughly parallel to the contours, which suggests near horizontal stratification. On the western side the diorite-shale subcrop is higher, suggesting about an 80 metre downthrow to the east. The aplite boundary shows no curvature in the valley or hillslopes, suggestiong that it is probably near vertical. Therefore, from the scale bar you can estimate the horizontal displacement. You now have horizontal and vertical components, so you can calculate the displacement vector. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The aplite dyke is probably a late-stage crystallization of the diorite, and is obviously pre-fault, pre-basalt dyke. In fact the basalt dyke is the most recent feature, probably thrown in a s a red herring!&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="5594" LastEditDate="2017-12-15T08:42:58.210" LastActivityDate="2017-12-15T08:42:58.210" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6656" PostTypeId="1" AcceptedAnswerId="6657" CreationDate="2015-10-05T08:59:05.973" Score="3" ViewCount="5099" Body="&lt;p&gt;I have two datasets that represent longitude in different ways. The first represents longitude as degrees from east to 180, but then as negative east so that I have a series which looks like:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;[0:180, -180:0];&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;I then have another dataset that represents longitude as degrees east but with a range of 0 to 360, i.e.:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;0:360;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;In order to convert these to the same format, can I simply use this?&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;lon2(lon2 &amp;gt; 180) = lon2(lon2 &amp;gt; 180)-360;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Note my example here is written in MATLAB. This basically shows that I can change the second longitude coordinates by simply subtracting 360 from those longitude values that are greater than 180. Does this make sense? &lt;/p&gt;&#xA;" OwnerUserId="4582" LastEditorUserId="28050" LastEditDate="2015-10-05T14:34:32.867" LastActivityDate="2022-04-11T22:46:13.393" Title="How do I convert between different east longitude coordinates?" Tags="|homework|matlab|geometry|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6657" PostTypeId="2" ParentId="6656" CreationDate="2015-10-05T09:21:26.423" Score="9" Body="&lt;p&gt;The database with the negative longitude angles is storing longitude as eastings and westings, whereas the other database is storing everything as eastings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It appears you prefer your data as eastings and westings. Your methodology for changing eastings greater than 180 degrees to westings is correct: where the longitude angle is greater than 180 subtract 360 from it (i.e. longitude angle - 360).&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-10-05T09:21:26.423" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6658" PostTypeId="1" CreationDate="2015-10-05T23:16:29.143" Score="2" ViewCount="181" Body="&lt;p&gt;Does anyone know of any examples of (common) time series analysis techniques applied to streamflow data?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit:  I am wondering if anyone has come across papers using common time series analysis techniques to identify the peaks in real time streamflow observations.  Additionally, I am wondering if once these peaks have been identified, if any further analysis (such as calculating the time of concentration) have been performed.&lt;/p&gt;&#xA;" OwnerUserId="2714" LastEditorUserId="2714" LastEditDate="2015-10-06T01:56:17.027" LastActivityDate="2015-10-06T01:56:17.027" Title="Time series analysis and streamflow data" Tags="|hydrology|" AnswerCount="0" CommentCount="2" ClosedDate="2017-03-10T13:14:37.493" ContentLicense="CC BY-SA 3.0" />
  <row Id="6659" PostTypeId="2" ParentId="6653" CreationDate="2015-10-06T05:39:34.573" Score="5" Body="&lt;p&gt;First, great question, though answers are likely to be non specific and speculative.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;As far as I understand, we are currently living in the Holocene, an&#xA;  interglacial period of the Quaternary glaciation, i.e. the current ice&#xA;  age that has so far lasted 2.6 million years. The Holocene began about&#xA;  12,000 years ago. While humans emerged about 200,000 years ago, human&#xA;  civilization is almost entirely coterminous with the Holocene.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As others have said, defining our current period as the Holocene is iffy.   Human influence is pretty huge, and perhaps, even as many as 6,000-7,000 years ago the growth of the agricultural revolution, some farm animal domestication and early, though much smaller, deforestation may have played a role in climate, at least, I remember reading that, though a quick google didn't provide a good source, but I've read that.   It's probably not consensus though, just some people's opinion.  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;(A) Are there any generally accepted estimates for how long the&#xA;  Holocene will last?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, how long?   There's 2 very different answers to this.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;First one, if we take out the human effect, or, lets say, in the relatively near future we &quot;fix&quot; our CO&lt;sub&gt;2&lt;/sub&gt; and other human effects on the planet and return the Earth mostly to how it was.   Then the answer is kind of simple, we just Look at past warm periods and make an estimate from those.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Without human activity the Holocene would very likely be just another inter-glacial warm period between ice ages in the continuation of the Quaternary with a similar length of time.  See chart:&lt;a href=&quot;https://i.stack.imgur.com/HawoQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HawoQ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;, If the average length of inter-glacial warm period is about about 20,000 to 40,000 years we can just subtract 11,000 from that and reach a rough estimate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or, if you want more accuracy, you can look closely at the 3 orbital cycles and calculate based on that - but I'm not going to do that as it would get more complicated.  More on that &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's also likely that there would be a cooling period within that time-frame.  We can see cooling, like the little ice age, without it being an actual ice age.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;When will glaciation resume? Has global warming delayed return to&#xA;  global cooling?&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;(B) Is anthropogenic global warming delaying the return to glaciation?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;First, it's worth pointing out that returning to global cooling and a return to glaciation aren't entirely the same thing.   If, lets say, we continue our CO&lt;sub&gt;2&lt;/sub&gt; footprint/production and reach 450 PPM before we cut back enough to level off for a few decades, then, cut back enough to see the oceans gradually take in CO&lt;sub&gt;2&lt;/sub&gt; and reduce the levels in the air, we could see a gradual global cooling within 100 years or so - maybe, provided the higher ocean temperatures and Albedo drop due to loss of ice cover didn't created a new equilibrium.   But in general, the earth can go through cooling periods without glaciation, so those 2 questions are similar but not entirely the same.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But in general, calculating glaciation with the human factor, it's a much harder question, especially since we can't see the future and how high CO&lt;sub&gt;2&lt;/sub&gt; levels will get.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Modern ice ages are defined as an advancing glaciation across a significant range of the Northern land, which, as pointed out above, coincides well with Milankovich cycles, but to actually have that happen, you need a few things in place.   Milankovich cycles don't cause ice ages all by themselves, cause they were there during non ice ages too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The modern ice age cycle only started about 2.6 million years ago and it is thought to have been brought about by the formation of Isthmus of Panama about 5 million years ago, which separated a current between the Atlantic and Pacific Oceans which helped the arctic ocean cool and freeze over.  Shortly after that Isthmus formed, the Earth began to cool.   &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Five_Myr_Climate_Change.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;See here&lt;/a&gt; (chart from Milankovich link above).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Modern ice ages also coincide with falling CO&lt;sub&gt;2&lt;/sub&gt; levels, and while the CO&lt;sub&gt;2&lt;/sub&gt; drop follows the temperature drop, there's a reason for that.  Colder oceans hold more CO&lt;sub&gt;2&lt;/sub&gt;, so the Atmospheric CO&lt;sub&gt;2&lt;/sub&gt; drops when temperature drops.  This serves as a feedback loop where cooling leads to more cooling and that's part of why ice ages are as big as they are.   Albedo is another feedback loop, so the trigger to get an ice age started is actually pretty small.   The Orbital cycles of the Earth are thought to only contribute about 1 degree of cooling in and of themselves and the other 9 or so degrees of global cooling between peak ice age and average Holocene is thought to be caused by these feedback mechanisms, primarily albedo and drops in atmospheric CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, there's 2 questions to ask as to whether man made global warming will prevent the next ice age and perhaps future ice ages.   We know that the Milankovich cycles will continue, but will CO&lt;sub&gt;2&lt;/sub&gt; be low enough for the cycle to lead to glaciation, and, how fast will CO&lt;sub&gt;2&lt;/sub&gt; levels drop, so, over the next 10,000 - 30,000 years.    Nobody knows the answer to those questions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looking at the last 800,000 years or so, based on ice-core samples, warm periods between ice ages you usually have about 260-280 PPM and peak ice age periods, about 180-200 PPM CO&lt;sub&gt;2&lt;/sub&gt; with the ranges in between, mostly during transitional periods.  When these changes occur, most of the CO&lt;sub&gt;2&lt;/sub&gt; is believed to be absorbed into or released from the oceans, though I see no reason why a smaller portion of the change couldn't be driven by changes in living bio-mass corresponding to the changes in temperature, ocean size and grow-able land area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By burning fossil fuels, we've added carbon that was effectively removed from the Carbon cycle. For a rough calculation for how much, every year we add a bit over 30 billion tons of CO&lt;sub&gt;2&lt;/sub&gt; by burning fossil fuels every year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Atmosphere, at 270 PPM with a mass of the Atmosphere, about 5.148 x 10&lt;sup&gt;18&lt;/sup&gt; KG is about 2,320 billion tons.   Since the industrial revolution, CO&lt;sub&gt;2&lt;/sub&gt; PPM has increased to about 400 PPM, which is an increase of about 1,030 billion tons (atmosphere only) with roughly about 400 billion tons (rough estimate), having been absorbed into the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oceans are estimated to store about 50 times the CO&lt;sub&gt;2&lt;/sub&gt; than the Atmosphere, &lt;a href=&quot;http://www.waterencyclopedia.com/Bi-Ca/Carbon-Dioxide-in-the-Ocean-and-Atmosphere.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;, so assuming that's accurate, Oceans currently store over 110,000 billion tons of CO&lt;sub&gt;2&lt;/sub&gt; and since the industrial revolution, we've added (ballpark) 1,400 billion tons from burning fossil fuels - about a 1.2 - 1.3% increase to the total CO&lt;sub&gt;2&lt;/sub&gt; in the Oceans, Air and Land-biosphere.   That's the crux of the question, what effect will that have.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Over enough time, like, 10,000-30,000 years when the next ice age might be due, the oceans could absorb most of the atmospheric CO&lt;sub&gt;2&lt;/sub&gt; and the effects could be fairly small.   But as the Earth warms and Oceans warm and warming oceans increases the Atmospheric CO&lt;sub&gt;2&lt;/sub&gt; cause oceanic absorption drops.  With warmer oceans there will be a new equilibrium and with that in mind, it's entirely possible that the new atmospheric CO&lt;sub&gt;2&lt;/sub&gt; equilibrium, if left to it's own devices, might already be sufficient to prevent ice ages for a long time, perhaps a few hundred thousand years.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Predicting atmospheric CO&lt;sub&gt;2&lt;/sub&gt; levels 10,000 to 30,000 years from now, for all practical purposes, impossible, and that's what we'd need to know to estimate if we've stopped the next ice age or not.   What we have done is increased the amount of CO&lt;sub&gt;2&lt;/sub&gt; in the biosphere of earth by about 1.2–1.3% and since we continue to burn fossil fuels, we're likely to have created an increase of 2% before alternatives are in place, perhaps a bit more than that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All of this, however, is probably irrelevant, cause we have some ability to trap CO&lt;sub&gt;2&lt;/sub&gt;.   It's not easy, but we can do it and if, as our technology improves and we begin a gradual CO&lt;sub&gt;2&lt;/sub&gt; trapping program, we could re-start the next ice age in 10,000 years or so, assuming that's what we want to do.   Now, I don't mean to make light of the CO&lt;sub&gt;2&lt;/sub&gt; problem cause we appear to be facing very big and real issues over the next 20-50-100 years and that's much harder to avoid at this point, but over 10,000 years, we could probably fix our CO&lt;sub&gt;2&lt;/sub&gt; situation and bring the Earth back into the ice age cycle, or, we could use CO&lt;sub&gt;2&lt;/sub&gt; to avoid future ice ages if that's preferred.  Collecting and trapping 1–2 trillion tons of fossil fuel generated CO&lt;sub&gt;2&lt;/sub&gt; isn't easy and we don't have nearly the technology to do that today, but over 10,000 years I feel pretty confident that we could be able to do it, provided we keep progressing technologically.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="725" LastEditDate="2017-03-10T01:13:40.447" LastActivityDate="2017-03-10T01:13:40.447" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6660" PostTypeId="2" ParentId="6642" CreationDate="2015-10-06T07:12:51.903" Score="0" Body="&lt;p&gt;I'm guessing you're talking about the cold-snap centered around October 2 and 3.  We got it here too in NYC.  It was surprisingly cold for 2 days for this time of year and it came on rather suddenly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.accuweather.com/en/us/buffalo-ny/14202/october-weather/349726&quot; rel=&quot;nofollow&quot;&gt;http://www.accuweather.com/en/us/buffalo-ny/14202/october-weather/349726&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't remember, and haven't been able to find a weather report from 4 days ago, so the precise reason for that cold snap escapes me, but it hit a significant part of the North-East US and perhaps a bit more than that.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Generally when wind blows in from the North, we get cold air, so that's probably about what happened.  The great lakes probably kept Buffalo slightly warmer during that period, not colder cause the late water was probably warmer than the air temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This &lt;a href=&quot;http://scijinks.jpl.nasa.gov/polar-vortex/&quot; rel=&quot;nofollow&quot;&gt;article&lt;/a&gt; is somewhat related, though I'm not sure how well it applies to the dates I think you're talking about.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2016-07-05T18:52:13.627" LastActivityDate="2016-07-05T18:52:13.627" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6661" PostTypeId="1" AcceptedAnswerId="6662" CreationDate="2015-10-06T09:41:25.677" Score="6" ViewCount="1460" Body="&lt;p&gt;The remains of a mammoth were recently unearthed in a Michigan farmer’s field &lt;a href=&quot;https://www.youtube.com/watch?v=jwsCKW8WJm8&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;sup&gt;[1]&lt;/sup&gt;&lt;/a&gt;. This find could provide new information on the activity of early humans in the area, experts at the University of Michigan have said. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The remains of the animal, thought to be 11,700-15,000 years old, show “evidence of human activity.” How do the scientists determine this age?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1]: &lt;a href=&quot;https://www.youtube.com/watch?v=jwsCKW8WJm8&quot; rel=&quot;nofollow noreferrer&quot;&gt;www.youtube.com/watch?v=jwsCKW8WJm8&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2626" LastEditorUserId="5594" LastEditDate="2017-12-15T08:41:03.243" LastActivityDate="2017-12-15T08:41:03.243" Title="How do scientists measure the age of old animal remains?" Tags="|measurements|paleontology|geochronology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6662" PostTypeId="2" ParentId="6661" CreationDate="2015-10-06T11:45:44.393" Score="12" Body="&lt;p&gt;Organic material (plants and animals) contains carbon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Carbon has three main isotopes: carbon 12, 13 and 14. Carbon 14 is radioactive, with a half life of 5730 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Carbon 14 is continuously created in the atmosphere by cosmic rays hitting nitrogen. The nitrogen atoms lose a proton when struck by cosmic rays, turning the affected nitrogen atom into an atom of carbon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The carbon 14 then reacts with oxygen in the atmosphere to create carbon dioxide. Plants taken in the radioactive carbon dioxide along with non radioactive carbon dioxide. Plant eating animals take in the radioactive carbon when they eat plants and meat eating animals take in radioactive carbon when they eat other animals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When a plant or animal dies it stops exchanging carbon with the environment and it dies with a certain amount of radioactive carbon 14.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By measuring how much carbon 14 is contained in a specimen and knowing the half life of carbon 14, scientists can calculate when an animal died.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Due to the half life of carbon 14 being 5730 years, carbon 14 dating can only reliably be used for dates up to 50 000 years old.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More details about carbon 14 dating can be found &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiocarbon_dating&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-10-06T11:45:44.393" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6664" PostTypeId="2" ParentId="5276" CreationDate="2015-10-07T16:01:36.053" Score="3" Body="&lt;p&gt;Lately, a couple of scientific discussions came up and challenged the conclusions of Goldstein et al., 2011 (see Katz &amp;amp; Starinsky comments to Torfsteins’s et al., (2015) paper, in EPSL)&#xA;A recent paper by Neugebauer et al. (2015) published in Climate of the Past discussions, interprets the gravel layer (which was presented as the main evidence for dry up or at least massive drawdown of the lake) as an artifact of the drilling process. So it seems that there is today no evidence for a complete dry up of the paleo Dead Sea. &lt;/p&gt;&#xA;" OwnerUserId="4590" LastActivityDate="2015-10-07T16:01:36.053" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6665" PostTypeId="1" CreationDate="2015-10-07T16:03:41.017" Score="8" ViewCount="913" Body="&lt;p&gt;I have a problem in deriving/understanding the vertical velocity in sigma-pressure coordinates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The vertical coordinate is defined as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\sigma(x,y,p)=\frac{p(x,y)-p_t}{p_s(x,y)-p_t}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $p(x,y)$ is the pressure of the considered grid point, $p_t$ is the pressure at the top of the domain (in my case $50$hPa) and $p_s(x,y)$ is the surface pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;After some derivation I get for the vertical velocity ($D/Dt$ is the total, $\partial/\partial t$ the partial derivative, $\omega = Dp/Dt$):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$w = \frac{D \sigma}{Dt} = - \frac{\sigma}{(p_s-p_t)}  \left(\frac{\partial p_s}{\partial x} u + \frac{\partial p_s}{\partial y} v \right) + \frac{1}{p_s-p_t} \omega$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I now think of an idealized example where I have a gaussian hill in the middle of the domain and wind coming only from the south ($v=10$ms$^{-1}$, $u$, $\omega=0$), the resulting vertical wind component is positive in front of the hill which is wrong since the air should be ascending (positive value of $w$ means descending).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where is my mistake?&lt;/p&gt;&#xA;" OwnerUserId="4591" LastEditorUserId="200" LastEditDate="2015-10-09T17:19:27.920" LastActivityDate="2015-12-29T03:29:01.117" Title="How is the vertical velocity defined in sigma-pressure-coordinates?" Tags="|meteorology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6666" PostTypeId="1" AcceptedAnswerId="6667" CreationDate="2015-10-07T17:09:53.657" Score="6" ViewCount="364" Body="&lt;p&gt;Areas where topography prevents the outﬂow of water are called closed basins. Is the GAB a closed basin? What if external bodies of water flowed in? Is that still &quot;closed&quot;?&lt;/p&gt;&#xA;" OwnerUserId="4592" LastActivityDate="2021-11-24T16:04:40.273" Title="Is the Great Artesian Basin a closed basin?" Tags="|hydrology|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6667" PostTypeId="2" ParentId="6666" CreationDate="2015-10-08T06:57:20.997" Score="3" Body="&lt;p&gt;In the far north of the Great Artesian Basin, there is groundwater outflow to the Gulf of Carpentaria. Everywhere else the aquifer behaves as a closed basin with outflow in the form of vertical seepage (e.g. to the Mound Springs of South Australia), artesian overflowing boreholes, and pumped boreholes. There may once have been hydraulic connection to the Southern Ocean, but that ceased several millions of years ago - not such a long time when one considers that the longest through-flow time of groundwater, from east to west, is about two million years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GJoUM.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GJoUM.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4487" LastEditDate="2015-10-25T22:15:36.987" LastActivityDate="2015-10-25T22:15:36.987" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="6668" PostTypeId="1" CreationDate="2015-10-08T15:23:41.470" Score="6" ViewCount="348" Body="&lt;p&gt;I would like to know if anybody knows the name of this cloud formation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The picture was taken in Bern Switzerland, just before a cold front moved in. I am thinking about roll clouds or Asperatus undulatus... It was wavy but the clouds formed rolls.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/A3QQ1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/A3QQ1.jpg&quot; alt=&quot;cloud rolling over Bern&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4597" LastEditorUserId="595" LastEditDate="2015-12-10T13:29:28.233" LastActivityDate="2016-05-14T00:08:00.983" Title="What kind of cloud is this?" Tags="|meteorology|clouds|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6670" PostTypeId="1" CreationDate="2015-10-08T22:13:27.187" Score="2" ViewCount="63" Body="&lt;p&gt;I know it has something to do with the rotation speed, but what exactly? And why?&lt;/p&gt;&#xA;" OwnerUserId="4599" LastActivityDate="2015-10-08T22:13:27.187" Title="What determines the number of Hadley cells on a planet?" Tags="|meteorology|" AnswerCount="0" CommentCount="0" ClosedDate="2015-10-09T07:14:02.723" ContentLicense="CC BY-SA 3.0" />
  <row Id="6671" PostTypeId="1" AcceptedAnswerId="6679" CreationDate="2015-10-09T03:27:10.017" Score="11" ViewCount="396" Body="&lt;p&gt;I was looking at the model ocean current maps from &lt;a href=&quot;http://earth.nullschool.net/#current/ocean/surface/currents/overlay=sea_surface_temp/orthographic=153.77,-31.32,2274&quot; rel=&quot;noreferrer&quot;&gt;earth :: a global map of wind, weather, and ocean conditions&lt;/a&gt; for 2015-10-07 00:00 UTC and there are a lot of odd-looking 'whirlpool' areas off the eastern coast of Australia. Anyone know the explanation? Is this a common occurrence? Is it related to the strong El Niño?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qAeJc.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qAeJc.jpg&quot; alt=&quot;Ocean currents off Australia&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1242" LastEditorUserId="111" LastEditDate="2015-10-09T21:25:41.187" LastActivityDate="2015-10-12T02:36:09.153" Title="What causes these odd-looking currents in the Tasman Sea?" Tags="|ocean|oceanography|ocean-currents|enso|pacific|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6672" PostTypeId="2" ParentId="6652" CreationDate="2015-10-09T04:23:35.737" Score="6" Body="&lt;p&gt;Remember that you are concerned about &lt;em&gt;stability fields&lt;/em&gt;. The lines on your stability diagram are the places where two minerals are in equilibrium. One one side one mineral will be more stable, on the other side the other one will be.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's talk about $\ce{Ca}$ first. The reactions all have the same $\ce{Ca}$ so it's activity isn't a factor in their relative stability. If you write a combined reaction for any mineral to another, it will cancel out. Try it. Calcite stability has nothing to do with $\ce{Mg}$ or $\ce{SO4}$ it's stability will only depend on $\ce{CO3}$ and $\ce{Ca}$. But wait, you know $\mathrm{ln}\,a_{\ce{CO3}}$ so you can calculate $\mathrm{ln}\,a_\ce{Ca}$ in equilibrium with calcite. So you can use that to help figure out where calcite is the most stable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You only have one equation where sulfate is included. What direction will that stability boundary take on your diagram? Say you want to divide your diagram space into areas of calcite vs gypsum stability, how could you combine the two solubility equations to come up with the conversion of one mineral to the other? What dissolved species activities enter into the equation (hint: you know one of the two). Given that you can figure out the other one and plot that on you diagram.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can you follow a similar process for calcite and dolomite (hint: yes)? What about calcite and huntite? Is there any part of the diagram where huntite is more stable than dolomite (or vice versa)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now figure out the stability relationship between dolomite and gypsum. What angle will the line take on your plot? Figure out where it will occur by combining reactions. This is a bit trickier but the $\mathrm{ln}\,a$ values will depend on the $\mathrm{ln}\,K$ for the combined reaction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now erase any lines in a field where those two minerals are less stable than anything else.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Good luck and let us know if you get stuck. I didn't want to just give you the answer because I'd have to actually work it out.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastEditorUserId="4487" LastEditDate="2015-10-25T05:48:25.940" LastActivityDate="2015-10-25T05:48:25.940" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6673" PostTypeId="2" ParentId="233" CreationDate="2015-10-09T10:02:26.227" Score="1" Body="&lt;p&gt;Perhaps surprisingly, the average rainfall per unit area over the ocean and continents is not much different, namely about 3.0 mm per m2 per day between +/-60 degrees of latitude (where most of the rain occurs). The oceanic average is based upon IR satellite date of cloud-top temperatures, which correlates pretty well with rainfall. Thinking of tropical rainfall, and particularly monsoon rainfall, there are many regions where the mean annual rainfall exceeds 6.0 mm per day. Against this must be considered the great desert areas where average rainfall is almost nil. The latitudinal variation is graphed in&#xA; &lt;a href=&quot;http://www.roperld.com/science/PrecipLatitude_Longitude.htm&quot; rel=&quot;nofollow&quot;&gt;http://www.roperld.com/science/PrecipLatitude_Longitude.htm&lt;/a&gt; .&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2016-09-06T14:54:26.540" LastActivityDate="2016-09-06T14:54:26.540" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6675" PostTypeId="1" CreationDate="2015-10-09T14:04:19.880" Score="6" ViewCount="87" Body="&lt;p&gt;I can't find any information regarding the lat and long in the NCEP Reanalysis. Do they represent the center of the cell?&lt;/p&gt;&#xA;" OwnerUserId="3061" LastEditorUserId="111" LastEditDate="2015-10-17T01:42:07.967" LastActivityDate="2015-10-17T01:42:07.967" Title="NCEP reanalysis latitude and longitude represent center of cell?" Tags="|meteorology|climate|reanalysis|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6676" PostTypeId="1" AcceptedAnswerId="6677" CreationDate="2015-10-09T14:37:39.783" Score="3" ViewCount="5857" Body="&lt;p&gt;What is the maximum value of Easting in UTM coordinates?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In many websites I found the answer of maximum value is about &lt;strong&gt;834000&lt;/strong&gt; meters, but if you convert some of these coordinates below the value will be much higher than that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Latitude: 61.44 Longitude: 25.40 --&gt; Converted in UTM: Sector: 35 V  Northing: 414668 Easting: &lt;strong&gt;6812844&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Latitude: -47.04 Longitude: -73.48 --&gt; Converted: Sector: 18 G Northing: 615471 Easting: &lt;strong&gt;4789269&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="2609" LastEditorUserId="124" LastEditDate="2015-10-12T17:57:28.960" LastActivityDate="2021-12-15T11:24:09.383" Title="What is the maximum value of Easting in UTM coordinates?" Tags="|projection|cartography|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6677" PostTypeId="2" ParentId="6676" CreationDate="2015-10-09T15:57:14.130" Score="5" Body="&lt;p&gt;&lt;strong&gt;You are correct about the maximum value, you just have the easting and northing backwards.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;In your first example, the &lt;em&gt;easting&lt;/em&gt; is 414668 m and the &lt;em&gt;northing&lt;/em&gt; is 6812844 m. The convention is eastings first. You can think of UTM coordinates as &lt;span class=&quot;math-container&quot;&gt;$(x, y)$&lt;/span&gt; pairs, and they are sometimes labelled as such. Here's the conversion offered by &lt;a href=&quot;http://rcn.montana.edu/Resources/Converter.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;one converter&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eMH3J.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eMH3J.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As you say, &lt;a href=&quot;https://www.maptools.com/tutorials/utm/details&quot; rel=&quot;nofollow noreferrer&quot;&gt;eastings are usually less than 834 000 m&lt;/a&gt;, and more than 160 000 m.&lt;/p&gt;&#xA;&lt;p&gt;Note than some UTM zones are non-standard widths. Also, you will sometimes see coordinates referenced to some neighbouring zone, which isn't a good idea but is sometimes convenient, so the numbers can be unexpectedly large. Lastly: be aware that in the US you may sometimes come across UTM coordinates in other units, such as feet. Horrible.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="25055" LastEditDate="2021-12-15T11:24:09.383" LastActivityDate="2021-12-15T11:24:09.383" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="6679" PostTypeId="2" ParentId="6671" CreationDate="2015-10-09T18:27:46.127" Score="10" Body="&lt;p&gt;Great question. These features are mesoscale Eddies and they are akin to hurricanes in the atmosphere. They are the ocean’s high or low pressure systems and are the result of instabilities. The cyclonic eddy (counterclockwise direction in the northern hemisphere) is called a cold-core eddy and the anti-cyclonic eddy is called a warm-core eddy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kri9D.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kri9D.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unlike destructive hurricanes, ocean eddies are important physical processes for the transport of heat and particulate matter. They stir up the ocean drawing up nutrients from the lower depths and fertilizing waters as they propagate. They are important for the transport of marine organisms in the offshore direction and support phytoplankton and zooplankton production.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the Tasman sea, this region is known as 'Eddy Avenue' which speaks to their ubiquity and persistence. In Everett (2012) they identified 30 thousand eddies in a period of $15$ years.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... at a density of 61 cyclonic and 63 anticyclonic eddies per $10,000$&#xA;  km$^2$. On any given day there are 16.8 cyclonic and 17.8 anticyclonic&#xA;  eddies within the Tasman Sea. Tasman Sea eddies are typically smaller&#xA;  than the global average ($82$ km radii compared with $86$ km), have a&#xA;  faster rotational speed ($23$ cm s$^{-1}$ compared with $15–16$ cm&#xA;  s$^{-1}$) and have a larger Sea Level Anomaly($10$ cm compared with&#xA;  $6–7$ cm) (Table 1).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Generation:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;“When the current separates from the coast, it gets complicated. It&#xA;  starts to wobble; it meanders. Rather than going in a relatively&#xA;  straight path like the Gulf Stream in the North Atlantic, it walks&#xA;  like a drunk man.” Not only does the EAC wobble, it U-turns. [...] The EAC is a bit  anomalous.” About two-thirds of the current retroflects back up into&#xA;  the eastern Pacific, breaking up the EAC further. “It really is a&#xA;  current of eddies.” Such instabilities saturate Eddy Avenue with&#xA;  eddies.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As far as the El-Niño connection, I can only speculate. But generally, El-Niño will give rise to positive SST anomalies. The figure below shows recent positive SST anomalies which are relatively strong near the coast. Because ocean temperatures are higher ocean eddies can increase in size and strength. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2ZryR.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2ZryR.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.363.5897&amp;amp;rep=rep1&amp;amp;type=pdf&quot; rel=&quot;noreferrer&quot;&gt;Everett, J. D., M. E. Baird, P. R. Oke, and I. M. Suthers. 2012. An avenue of eddies: Quantifying the biophysical properties of mesoscale eddies in the Tasman Sea. Geophysical Research Letters 39, L16608, doi:10.1029/2012GL053091.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2015-10-09T19:34:58.450" LastActivityDate="2015-10-09T19:34:58.450" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6680" PostTypeId="1" CreationDate="2015-10-10T01:10:22.447" Score="7" ViewCount="446" Body="&lt;p&gt;How will global warming influence climate systems such as the &lt;a href=&quot;http://en.wikipedia.org/wiki/Madden%E2%80%93Julian_oscillation&quot; rel=&quot;nofollow&quot;&gt;Madden–Julian Oscillation&lt;/a&gt; (MJO) or the &lt;a href=&quot;https://en.wikipedia.org/wiki/El_Ni%C3%B1o_Southern_Oscillation#On_global_warming&quot; rel=&quot;nofollow&quot;&gt;El Niño Southern Oscillation (ENSO)&lt;/a&gt;? &lt;/p&gt;&#xA;" OwnerUserId="4603" LastEditorUserId="543" LastEditDate="2015-12-05T19:28:22.680" LastActivityDate="2017-02-05T19:08:51.623" Title="How will global warming affect climate systems like the ENSO or the MJO?" Tags="|climate-change|climate-models|enso|atmosphere-modelling|ocean-models|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="6681" PostTypeId="1" CreationDate="2015-10-10T10:27:03.953" Score="5" ViewCount="56" Body="&lt;p&gt;I need data on depth/thickness of of different lithologic units under Deccan Volcanic Province in MP, Maharashtra and Gujarat. For this if anyone can help in providing help in obtaining well log data on lithology in aforementioned region, kindly help. The depth of more than 100 m required.&lt;/p&gt;&#xA;" OwnerUserId="4605" LastEditorUserId="725" LastEditDate="2017-05-14T03:43:32.023" LastActivityDate="2017-05-14T03:43:32.023" Title="Lithologic and hydrostratigraphic logs for the Deccan volcanic province, India" Tags="|geology|hydrology|petrology|stratigraphy|database|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6682" PostTypeId="1" CreationDate="2015-10-10T11:16:00.503" Score="6" ViewCount="464" Body="&lt;p&gt;What are the processes, chemicals and particles involved in creating colour in a planet's sky? Could you give some examples of sky colour processes different from what happens on Earth?&lt;/p&gt;&#xA;" OwnerUserId="4606" LastEditorUserId="4487" LastEditDate="2015-10-11T01:10:47.620" LastActivityDate="2018-12-26T21:43:31.287" Title="What would a planet's sky look like with different chemical compositions, such as low nitrogen, high methane etc?" Tags="|atmosphere|planetary-science|clouds|atmospheric-radiation|atmospheric-chemistry|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6683" PostTypeId="2" ParentId="6611" CreationDate="2015-10-10T11:56:04.813" Score="2" Body="&lt;p&gt;It's a curious question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I agree with Gordon Stranger, without context, (and a mention of some link to peer reviewed research, or at least, some kind of measurement), it's pretty meaningless.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I did a a google search and checked links with books.google.com in them to search for a source but everything refers back to UNCCD and UNCCD, as far as I read their reports, never explains or provides a source for that sentence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.com/?gws_rd=ssl#q=Arable%20land%20loss%20is%20estimated%20to%20be%20at%2030%20to%2035%20times%20the%20historical%20rate&amp;amp;btnK=Google%20Search&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google Search for books&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.unccd.int/en/resources/publication/Pages/default.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;List of reports&lt;/a&gt; I went through a few - no luck.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I did find this:   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2zXhn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2zXhn.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.landcommodities.com/farmland-supply-and-investment-fundamentals/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;:  but the problem is, they're using a different criteria than you.   Forest can be cleared to create new arable land, so that's why they show an increase when UNCCD shows a decrease.   If you combine this chart with deforestation, you might have something a little bit close to what you're looking for.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the US, (edit) farm land (not necessarily arable land) has decreased but food production has increased due to improved technology, fertilizer and all that good stuff.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.ers.usda.gov/media/1874727/mon-ag-outputs-and-inputs.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chart&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.ers.usda.gov/data-products/charts-of-note.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bad farming methods leads to loss of arable land much faster than good methods.   &lt;a href=&quot;https://earthscience.stackexchange.com/questions/400/what-started-the-us-dust-bowl-of-the-1930s-and-could-it-happen-again&quot;&gt;Here's a good answer&lt;/a&gt; on the dustbowl that you might find interesting and even early societies, thousands of years ago, they lost arable land cause there were processes that happened that they didn't understand, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/5134/did-the-neolithic-revolution-have-an-effect-on-the-earths-climate&quot;&gt;explained more here&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Environmental effects, mostly tend to be cyclical and are probably harder to measure outside of human effects.   California might have a big drought one year and have a great growing season the next.  The droughts we experience don't make the land permanently not arable, just for 1 growing season.   Floods - might have a bigger effect if they wash away good land but they can also have the opposite effect, depositing rich silts adding nutrients to the soil.   Over long term, climate change can affect arable land, for example, 13,000 years ago / give or take, the Sahara was a rich forest with huge lakes (We know this by fossils that remain there) and that may be a cycle that comes and goes with every orbital tilt of the Earth.   During the last ice age, much land was covered by ice, but lower sea levels left lots of rich valleys that are now covered by water.  The story of Noah and Gilgamesh are thought to be based on the flooding of one such fertile valley, caused in part by the end of the ice age and rising water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, at least from an environmental perspective, it's a complicated question with lots of moving parts.    Hope that helps, though I'm not sure it does.  I was curious about what you asked so I looked into it a bit.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-10-12T05:06:01.000" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6684" PostTypeId="1" AcceptedAnswerId="6690" CreationDate="2015-10-10T13:14:05.743" Score="11" ViewCount="1487" Body="&lt;p&gt;There's a story going around the low-grade news factories that one &lt;a href=&quot;https://en.wikipedia.org/wiki/David_Evans_(mathematician_and_engineer)&quot;&gt;Dr. David Evans&lt;/a&gt; has predicted that the world will &lt;a href=&quot;http://www.express.co.uk/news/science/611111/Former-government-expert-disproves-climate-change-and-says-world-will-soon-cool-down&quot;&gt;start cooling down in 2017&lt;/a&gt;. One source reports:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;He says fundamental flaws in how future temperatures may rise have been included in the 'standard models' and this has led to inflated mathematical - and therefore temperature - predictions.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://nextgrandminimum.wordpress.com/&quot;&gt;Googling&lt;/a&gt; &lt;a href=&quot;http://www.climatedepot.com/2014/06/29/scientists-and-studies-predict-imminent-global-cooling-ahead-drop-in-global-temps-almost-a-slam-dunk/&quot;&gt;finds&lt;/a&gt; a &lt;a href=&quot;http://joannenova.com.au/2014/06/big-news-viii-new-solar-model-predicts-imminent-global-cooling/&quot;&gt;number&lt;/a&gt; of &lt;a href=&quot;http://www.adelaidenow.com.au/news/national/miranda-devine-perth-electrical-engineers-discovery-will-change-climate-change-debate/story-fnii5thp-1227555674611?nk=559efafea17bd10a7aeb25966cdfffc6-1444481823&quot;&gt;other&lt;/a&gt; &lt;a href=&quot;http://www.perthnow.com.au/news/opinion/miranda-devine-perth-electrical-engineers-discovery-will-change-climate-change-debate/news-story/d1fe0f22a737e8d67e75a5014d0519c6?nk=559efafea17bd10a7aeb25966cdfffc6-1444481794&quot;&gt;sites&lt;/a&gt; with the &lt;a href=&quot;http://technocracy.news/index.php/2015/10/09/top-climate-scientist-says-global-cooling-starts-in-2017/&quot;&gt;same&lt;/a&gt; &lt;a href=&quot;http://iceagenow.info/2015/10/engineers-discovery-could-change-climate-change-debate/&quot;&gt;story&lt;/a&gt;. Some identify Dr. Evans as a &quot;former climate modeler for the Australian Greenhouse Office&quot;, others as an electrical engineer. None seem to provide any skepticism about Dr. Evans' statements.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm sure this is a sham, as otherwise it would be an enormously important story that would be reported everywhere. If so, I'm a little surprised that I found no &quot;boy is this stupid&quot; responses. Perhaps the real climate experts are tired of playing &quot;climate conspiracy &lt;a href=&quot;https://en.wikipedia.org/wiki/Whac-A-Mole&quot;&gt;Whack-A-Mole&lt;/a&gt;&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a &lt;a href=&quot;http://www.express.co.uk/news/clarifications-corrections/526191/Climate-change-is-a-lie-global-warming-not-real-claims-weather-channel-founder&quot;&gt;climate change denier&lt;/a&gt; were to use this story as proof that anthropogenic global warming is a scam to keep earth scientists employed, what would be the best way to show that he is wrong?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt; I just found that Dr. Evans serves on the Board of Advisors of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Committee_for_a_Constructive_Tomorrow&quot;&gt;Committee for a Constructive Tomorrow&lt;/a&gt;, an NGO that denies man-made global warming exists.&lt;/p&gt;&#xA;" OwnerUserId="534" LastEditorUserId="534" LastEditDate="2015-10-10T16:55:52.863" LastActivityDate="2022-05-24T14:32:59.490" Title="&quot;The world will start COOLING DOWN in 2017&quot;?" Tags="|climate-change|climate-models|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="6685" PostTypeId="2" ParentId="4728" CreationDate="2015-10-10T13:30:35.687" Score="1" Body="&lt;p&gt;Gravitational dynamics of the Greenland Ice sheet have an impact, sea level fall, not often mentioned (e.g. on Europe: &lt;a href=&quot;http://blogdredd.blogspot.com/2015/10/proof-of-concept-5.html&quot; rel=&quot;nofollow&quot;&gt;Proof of Concept - 5&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It causes sea level fall and sea level rise, depending on distance from the ice sheet (&lt;a href=&quot;http://ecocosmology.blogspot.com/2015/08/the-gravity-of-sea-level-change.html&quot; rel=&quot;nofollow&quot;&gt;The Gravity of Sea Level Change&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="4607" LastActivityDate="2015-10-10T13:30:35.687" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6686" PostTypeId="2" ParentId="4728" CreationDate="2015-10-10T15:12:07.140" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3tMxR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3tMxR.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The graph shows sea level fall (SLF) at the Churchill tide gauge station.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is on the west side of Hudson Bay.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These jagged edge ups and downs, and severe drop in a short time, indicate this is not the result of rising land mass. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Greenland ice mass loss is the source of SLF in a wide area.&lt;/p&gt;&#xA;" OwnerUserId="4608" LastActivityDate="2015-10-10T15:12:07.140" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6687" PostTypeId="2" ParentId="6682" CreationDate="2015-10-10T17:45:47.760" Score="7" Body="&lt;p&gt;Except for Rayleigh scattering (&lt;a href=&quot;https://earthscience.stackexchange.com/questions/3063/is-the-color-of-the-sky-the-same-everywhere-on-earth&quot;&gt;Is the color of the sky the same everywhere on earth?&lt;/a&gt;) gases typically do not add &lt;strong&gt;&lt;em&gt;any&lt;/em&gt;&lt;/strong&gt; color to atmospheres, they are usually transparent in visible light. The Halogen gases (F&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;, Cl&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;,Br&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;, I&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;) have color though, and there are a few other colored molecular gases, but you would not expect them in planetary atmospheres.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The color in planetary atmospheres comes almost exclusively from particulates, such as hazes (smog basically), ice crystals (not just water), and mist with chemicals in solution. The &lt;a href=&quot;http://en.wikipedia.org/wiki/Atmosphere_of_Titan&quot; rel=&quot;nofollow noreferrer&quot;&gt;atmosphere of Titan&lt;/a&gt; is colored by tholins: organic molecules of H, N, C, O and possibly S. The &lt;a href=&quot;http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_pre_2011/periodic_table/group7rev1.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;other planets' atmospheres are colored&lt;/a&gt; by particulates such as ammonia ices (NH&lt;sub&gt;3&lt;/sub&gt;), sulfuric acid droplets (H&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt;), tholins, and other exotic stuff.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is important to note the color reflected or scattered by an atmosphere can be quite different than the color transmitted through an atmosphere, which is why our sky is blue in the daytime but reddish at dusk or dawn. So the color of exotic clouds or haze on other planets may look completely different seen from below rather than above.&lt;/p&gt;&#xA;" OwnerUserId="4487" LastEditorUserId="4487" LastEditDate="2018-12-26T21:43:31.287" LastActivityDate="2018-12-26T21:43:31.287" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="6688" PostTypeId="2" ParentId="6668" CreationDate="2015-10-10T20:57:11.470" Score="1" Body="&lt;p&gt;I think it is stratocumulus. Sometimes it rolls like that. Nice picture&lt;/p&gt;&#xA;" OwnerUserId="4610" LastActivityDate="2015-10-10T20:57:11.470" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6689" PostTypeId="1" AcceptedAnswerId="6691" CreationDate="2015-10-10T21:19:57.330" Score="2" ViewCount="54" Body="&lt;p&gt;Below is a roadcut in central Marin County, California, in an area maps show to have Franciscan melange.  I assume this is graywacke, but as you can see it varies from gray on the sides to a buff color in the center.  Is the buff section due to some chert content, or did that section weather differently (and if so why)?  Thanks!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Q0nzA.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Q0nzA.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4611" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T11:53:10.940" LastActivityDate="2019-08-29T11:53:10.940" Title="Why does the color of this hillside rock vary?" Tags="|petrology|california|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6690" PostTypeId="2" ParentId="6684" CreationDate="2015-10-10T22:54:39.290" Score="16" Body="&lt;p&gt;I gave a longer answer linked to a similar question in the comments above, I'll give a quick one here:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;There's a story going around the low-grade news factories that one Dr.&#xA;  David Evans . . .&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Everyone knows there's a fair bit of &quot;I know you are but what am I&quot; in the climate change debate (if you can even call it a debate), but whichever side you agree with, David Evans is without question, actively arguing the skeptic side.  His position has been consistently in disagreement with man made climate change for nearly a decade, so anything of his you read, keep that in mind. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;He's made two climate &quot;denier lists&quot; &lt;a href=&quot;https://watchingthedeniers.wordpress.com/climate-sceptic-conspiracies/profile-dr-david-evans/&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;https://denierlist.wordpress.com/2013/02/26/dr-david-evans/&quot;&gt;here&lt;/a&gt; and he has been called out by skeptical science, &lt;a href=&quot;http://www.skepticalscience.com/david-evans-understanding-goes-cold.html&quot;&gt;here&lt;/a&gt;.    In another article related to yours, &lt;a href=&quot;http://www.theaustralian.com.au/news/miranda-devine-perth-electrical-engineers-discovery-will-change-climate-change-debate/story-e6frg6n6-1227555674611&quot;&gt;here&lt;/a&gt;, it says his work is &quot;undergoing peer review&quot;, so for now, his calculations aren't publicly available or verified.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;. . . has predicted that the world will start cooling down in 2017&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;One problem here.  We're currently in an &lt;a href=&quot;http://www.weather.com/news/climate/news/strong-el-nino-noaa-update-october2015&quot;&gt;El Nino&lt;/a&gt; and 2014 was the warmest year on record (38% probability to some, but lets not go there) with 2015 likely to break that record and 2016 - too soon to say but the El Nino is expected to extend into 2016, so 2017 is an ideal year to predict cooling.  The global temperature often drops within a year after an El Nino ends, but this is a normal cycle and temporary and it has nothing to do with man made climate change.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What would be the best way to show that he is wrong?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Well, a personal favorite, I'd go with something like: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;&quot;He's just using a mathematical model to predict the future.  I thought you people hated mathematical models to predict the future. -&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could also bring up this &lt;a href=&quot;http://www.skepticalscience.com/David_Evans_arg.htm&quot;&gt;list&lt;/a&gt; of examples where David Evans has been wrong in the recent past.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the more scientific answer to your question is that until his research is available and peer reviewed, then there's no way to disprove it, but there's also, no good reason to agree with it.   Without peer review and transparency, it's not science.   It's just a blog.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2015-10-11T01:39:05.323" LastActivityDate="2015-10-11T01:39:05.323" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6691" PostTypeId="2" ParentId="6689" CreationDate="2015-10-11T01:24:22.727" Score="3" Body="&lt;p&gt;It's pretty hard to say anything about this kind of weathering without actually being there and having a closer look.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Usually, the simplest explanation for reddish or brownish colours in otherwise grey rocks is the presence of iron oxides. You can see that the brown area is on a fault or joint face. This leads me to think that maybe this was a conduit for groundwater that oxidised the rock. When the road cut (or whatever it is) was made, this part was exposed. Notice that you have some brown elsewhere - it could be that those are faults or joints cut perpendicular to the face, so that's why you only see a brown streak instead of a surface.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-10-11T01:24:22.727" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6692" PostTypeId="2" ParentId="6528" CreationDate="2015-10-11T02:39:28.790" Score="3" Body="&lt;p&gt;Pretty darn accurate. To first order, the atmosphere's mass is the average atmospheric pressure at the Earth's surface times the total surface area divided by the acceleration due to Earth's gravity. Or if you prefer, $$ M_{\mathrm{atm}_\bigoplus} = \frac1{g_{_\bigoplus}}\int_{{\textstyle\!A}_\bigoplus} \!\!\!\!\! P_{\mathrm{surf}} = \frac1{g_{_\bigoplus}}\int_{\theta} \! \int_{\phi} \sin (\phi) R^2_{\scriptscriptstyle \bigoplus} P_{\mathrm{surf}}(\theta,\phi) $$ This is very slightly wrong because some of the atmosphere is further away where gravity is less, leading to a ~0.25% underestimate of the mass of $ M_{\mathrm{atm}_\bigoplus} $. The quick estimate would be pressure at sea level times total area of the Earth divided by gravitational acceleration, $$ M_{\mathrm{atm}_\bigoplus} \approx \frac{4\pi R^2_{\scriptscriptstyle \bigoplus} P_{\mathrm{sea\,level}}}{g_{_\bigoplus}} $$ Plugging in actual numbers, $$ M_{\mathrm{atm}_\bigoplus} \approx \frac{(12.6) \,\,(6.4 \times10^6\mathrm{m})^{\textstyle 2} \,(1.01\times10^5 \mathrm{kg}\,\,\mathrm{m}^{-1}\mathrm{s}^{-2})}{(9.8\,\mathrm{ms}^{-2})} \approx \underline{\mathbf{5.3 \times 10^{18}\,kg}} $$ or about 58 quadrillion American tons.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Water is rather incompressible, so integrating the density of water (1 g/cm$^2$) times ocean depth over the surface of the oceans will get you close. This is a data intensive calculation, but all the data is well known. Then, there is the liquid water outside the oceans, about 1.75% of total water, most of which is subsurface groundwater (fresh and saline). Free surface water, like lakes, is negligible. See &lt;em&gt;&lt;a href=&quot;http://water.usgs.gov/edu/earthwherewater.html&quot; rel=&quot;nofollow&quot;&gt;Where is the Earth's Water&lt;/a&gt;&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another 1.75% of water is frozen in glaciers and ice caps. This is the hardest to calculate because the depths of the ice caps over land and sea is not precisely known.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using the table at the bottom of &lt;em&gt;&lt;a href=&quot;http://water.usgs.gov/edu/earthwherewater.html&quot; rel=&quot;nofollow&quot;&gt;Where is the Earth's Water&lt;/a&gt;&lt;/em&gt; we find that there is about 1.34 billion cubic kilometers $(1.34\times10^9\,\mathrm{km}^3)$ of ocean and sea water. Add groundwater, and it becomes $1.36\times10^9\,\mathrm{km}^3$. Each cubic kilometer weighs a trillion kilograms $(10^{12}\,\mathrm{kg})$ so $M_{\mathrm{hydro}_\bigoplus}$ is about $\,$ $\underline{\mathbf{1.36\times10^{21}\,kg}}\,$, or 250 times the mass of the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Using the same source, the $M_{\mathrm{cryo}_\bigoplus}$ is about $\,\,\underline{\mathbf{2.4\times10^{19}\,kg}}$ .&lt;/p&gt;&#xA;" OwnerUserId="4487" LastEditorUserId="4487" LastEditDate="2015-10-12T16:53:05.273" LastActivityDate="2015-10-12T16:53:05.273" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6693" PostTypeId="1" AcceptedAnswerId="6702" CreationDate="2015-10-11T03:03:13.163" Score="4" ViewCount="138" Body="&lt;p&gt;I live in Hong Kong. Two days ago, the average daily temperature was around 27–28 °C and in yesterday, it was around 22–23 °C (during daytime it was rather hot i.e. 26–27 °C and it was at night that the temperature plummet) and today it is 19–20 °C in the morning. I am a newbie in climate/weather science so I would be very much appreciated if you can provide a more comprehensive answer.&lt;/p&gt;&#xA;" OwnerUserId="3241" LastEditorUserId="725" LastEditDate="2017-05-14T03:41:39.820" LastActivityDate="2017-05-14T03:41:39.820" Title="What are the possible mechanisms that could cause a rapid drop of temperature over few days?" Tags="|meteorology|temperature|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6694" PostTypeId="1" CreationDate="2015-10-11T07:47:00.447" Score="6" ViewCount="245" Body="&lt;p&gt;Earth is rotating so it has a ellipsoidal shape. The measurement will therefore be different from equator and pole. So why do we measure eustatic sea-level from the center of earth?&lt;/p&gt;&#xA;" OwnerUserId="4613" LastEditorUserId="11908" LastEditDate="2019-03-17T19:42:07.090" LastActivityDate="2019-03-17T19:42:07.090" Title="Why do we measure eustatic sea-level from the center of earth?" Tags="|geology|geophysics|sea-level|geodesy|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6695" PostTypeId="1" AcceptedAnswerId="6718" CreationDate="2015-10-11T11:38:52.123" Score="2" ViewCount="1145" Body="&lt;p&gt;How is climate and soil fertility different in Scandinavia comparing to Russian territory of 1500s? Did Scandinavia have more favorable climate and more of arable and higher yielding soil than Russia of 1500s did?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/S7eqy.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/S7eqy.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4552" LastActivityDate="2015-10-14T00:14:16.333" Title="How does soil fertility differ between Scandinavia and Russia" Tags="|climate|soil|agriculture|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6698" PostTypeId="1" CreationDate="2015-10-11T19:09:13.967" Score="18" ViewCount="2172" Body="&lt;p&gt;The title says it all...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/N88mR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/N88mR.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I assume it requires very slow freezing sheltered from the wind. Undercooled water, maybe?&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A &lt;a href=&quot;https://www.reddit.com/r/pics/comments/2x05t3/frozen_pond_in_switzerland/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reddit thread&lt;/a&gt; talks about &lt;a href=&quot;https://en.wikipedia.org/wiki/Delaunay_triangulation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Delaunay triangulation&lt;/a&gt;, but that does not explain how it forms. &lt;/li&gt;&#xA;&lt;li&gt;Many sites claim it is in Switzerland without further info.&lt;/li&gt;&#xA;&lt;li&gt;A comment in &lt;a href=&quot;https://www.reddit.com/r/interestingasfuck/comments/2qam4b/frozen_pond/&quot; rel=&quot;nofollow noreferrer&quot;&gt;another Reddit thread&lt;/a&gt; states &lt;em&gt;It happens when there is a significant change in gravitational force during the freezing process.&lt;br /&gt;&#xA;Also, there was a lot of water vapor hovering just above the surface during a rapid freezing process&lt;/em&gt;, but I doubt that gravitational effect.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;hr&gt;&#xA;BTW While researching this I found this beautiful page &lt;a href=&quot;http://www.earthporm.com/18-beautiful-frozen-lakes-oceans-ponds-resemble-fine-art/&quot; rel=&quot;nofollow noreferrer&quot;&gt;18 Beautiful Frozen Lakes, Oceans And Ponds That Resemble Fine Art&lt;/a&gt; - several of the pictures there would merit a separate question ;-)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It has a similar picture claiming to be from a frozen pond In Southern Oregon, USA&lt;sup&gt;*&lt;/sup&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CB9Eu.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CB9Eu.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;* But a Google image search finds claims of Switzerland, again.&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="595" LastEditorUserId="4487" LastEditDate="2015-10-25T00:28:11.083" LastActivityDate="2018-01-31T23:41:39.467" Title="Is this ice cover real - and what circumstances are required to make it?" Tags="|meteorology|wind|water|ice|crystals|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6699" PostTypeId="1" CreationDate="2015-10-11T19:12:37.370" Score="6" ViewCount="1781" Body="&lt;p&gt;I have a coprolite that is 8&quot; by 5&quot; and weighs 8 lbs. The shape is similar to a lumpy brain, the colors below outer crust are deep red and the crust is pastel green and grey. It has a strong density and can't be chipped with a hammer. It came from the Grand Canyon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are some pics:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TEzhD.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TEzhD.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/3NVKp.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3NVKp.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/2Qkvh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2Qkvh.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/B9y3D.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/B9y3D.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4617" LastEditorUserId="595" LastEditDate="2015-10-13T09:56:47.423" LastActivityDate="2015-10-13T13:07:40.010" Title="How to identify a predator's coprolite from an herbivore's?" Tags="|rocks|paleontology|fossils|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6700" PostTypeId="1" CreationDate="2015-10-12T01:09:54.910" Score="4" ViewCount="194" Body="&lt;p&gt;I want to model point source pollution in S. America watersheds. Specifically, given a set of pollution points and corresponding pollution output levels, I want to know the course these pollutants will take in the watershed and the accumulation levels. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there software that will do this? &lt;/p&gt;&#xA;" OwnerUserId="4619" LastEditorUserId="595" LastEditDate="2016-07-25T11:35:07.837" LastActivityDate="2016-07-25T11:35:07.837" Title="Point source pollution model for South America" Tags="|models|hydrology|pollution|software|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6701" PostTypeId="2" ParentId="6694" CreationDate="2015-10-12T01:19:09.773" Score="6" Body="&lt;p&gt;The centre of the Earth is the only true unchanging datum.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Land masses rise and fall due to geological actions such as melting of land based ice sheets, volcanism, plate tectonics, erosion, sedimentation and ground stresses causing land masses to move relative to one another at faults.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As stated &lt;a href=&quot;https://en.wikipedia.org/wiki/Sea_level#Sea_level_change&quot;&gt;here&lt;/a&gt;, sea level changes resulting from,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Eustatic change (as opposed to local change) results in an alteration to the global sea levels due to changes in either the volume of water in the world oceans or net changes in the volume of the ocean basins.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;With the elevation of land altering over time (rising or falling depending on location), the true change in sea levels cannot be determined from using points on the Earth's surface as a datum; particularly when the volume of the ocean basins changes due to land mass movements.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;True changes in sea levels can only be ascertained from an unchanging datum, which on Earth is the centre of the Earth.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-10-12T01:19:09.773" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6702" PostTypeId="2" ParentId="6693" CreationDate="2015-10-12T02:23:22.100" Score="6" Body="&lt;p&gt;If you look at the first picture, it is the barometric (atmospheric pressure) map of the Honk Kong region for 12 October 2015, from the Hong Kong observatory &lt;a href=&quot;http://www.hko.gov.hk/wxinfo/currwx/wxcht.htm&quot; rel=&quot;noreferrer&quot;&gt;website&lt;/a&gt;. Barometric maps don't change radically over the a period of a few days. The second picture is a similar map for the south east Asia region as at 8 am on 11 October 2015. It is from the same web page as the first picture, I just selected an earlier date from the upper right of the page.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some things to note about the first picture:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Temperatures in Beijing, Seoul and Hong Kong are 12, 10 and 21&#xA;degrees Celsius respectively. It's much colder in Beijing and Seoul than it is in Hong Kong.&lt;/li&gt;&#xA;&lt;li&gt;There is a high pressure system to the north of Hong Kong and to the&#xA;west of Shanghai which appears is part of a larger high pressure system WNW of Beijing. There also appears to be a low pressure system to the&#xA;north of Japan (which is confirmed in the second picture).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In the northern hemisphere, air flows clockwise around high pressure systems and counter-clockwise around low pressure systems.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The affect of the high pressure systems over China combined with the low pressure system to the north of Japan is to funnel cold air from the northern latitudes to the southern latitudes. This brought a significant amount of cold air to Hong Kong which caused the temperature to drop.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you look at Manila, in the Philippines, it is a relatively short distance from Hong Kong. It's temperature is 27 degrees Celsius compared to 21 for Hong Kong.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you look at the first picture, there is a low pressure system just to the west of the Philippines. With air moving counter-clockwise around low pressure systems, warm air from the equatorial regions is being drawn northwards along the western parts of the Philippines maintaining a very warm temperature in Manila.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Currently, Hong Kong and Manila are being influenced by different weather system and that's why there is a significant difference in the temperatures between the two locations despite their close proximity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tJ9o8.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tJ9o8.gif&quot; alt=&quot;Barometric Map of Hong Kong 2015.10.12&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Barometric Map of Hong Kong for 12 October 2015&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ChQDt.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ChQDt.gif&quot; alt=&quot;Barometric Map of South East Asia as at 0800 2015.10.11&quot;&gt;&lt;/a&gt;&#xA;&lt;strong&gt;&lt;em&gt;Barometric Map of South East Asia as at 0800 11 October 2015&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-10-12T02:23:22.100" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6703" PostTypeId="2" ParentId="6671" CreationDate="2015-10-12T02:36:09.153" Score="4" Body="&lt;p&gt;I'm posting this as an answer rather than a comment to expand a bit on the excellent answer from Isopycnal Oscillation and note some minor differences I observed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I had actually looked for temperature and temperature anomaly differences in the middle of the eddies and didn't see them prior to posting the question so it didn't look like upwelling at first. Here is an image from 2015-10-12 That shows some interesting features.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The areas of positive and negative anomalies actually include several eddies. This is particularly noticeable in the red/yellow areas which seem to be strengthening - there were more groups of blue a few days ago and little yellow. So it appears the vertical motion covers a larger area than individual mesoscale eddies. Is that correct?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other thing to notice is that the yellow - high positive anomaly is aligned with the high surface current around the eddies, not in the centre. I'm not sure why that is, but seems to indicate that the eddy currents are being driven by the temperature/flow differences between them.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/90XNx.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/90XNx.jpg&quot; alt=&quot;Tasman Sea Temperature Anomaly and Currents&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2015-10-12T02:36:09.153" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6704" PostTypeId="2" ParentId="6611" CreationDate="2015-10-12T06:24:27.280" Score="2" Body="&lt;p&gt;&lt;strong&gt;&lt;em&gt;EDIT -- &lt;a href=&quot;http://www.grida.no/publications/other/geo2000/&quot; rel=&quot;nofollow&quot;&gt;Found the full report ... in Norway.&lt;/a&gt;&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The quote you are trying to source was an oft repeated (1999-2002) talking point by Klaus Toepfer (Töpfer), head of UNEP. &lt;a href=&quot;http://www.grida.no/news/default/1961.aspx&quot; rel=&quot;nofollow&quot;&gt;The oldest instance I can find is in London, 1999.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The rate at which arable land is being lost is increasing and is&#xA;  currently 30-35 times the historical rate. Only about one and a half&#xA;  billion hectares remain out of the original three and a half billion.&#xA;  The loss of potential productivity due to soil erosion world wide is&#xA;  estimated to be equivalent to some 20 million tons of grain per year&#xA;  or 1% of global production.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Other later versions of his quote form a larger paragraph with one or two preceding sentences about soil loss in Africa, so the scope may not in fact be global. He and several others sometimes credit the UNEP Global Environment Outlook 2000 (GEO-2000) report, then link to &lt;a href=&quot;http://www.grid.unep.ch/geo2000/ov-e.pdf&quot; rel=&quot;nofollow&quot;&gt;this overview&lt;/a&gt;. I have electronically combed through the above overview and found nothing &lt;strike&gt;and I can not find a full report online. There are many alleged links, but they all go to the overview.&lt;/strike&gt; FOUND IT &lt;a href=&quot;http://www.grida.no/publications/other/geo2000/&quot; rel=&quot;nofollow&quot;&gt;HERE&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="4487" LastEditorUserId="4487" LastEditDate="2015-11-01T19:59:22.840" LastActivityDate="2015-11-01T19:59:22.840" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6705" PostTypeId="1" CreationDate="2015-10-12T14:37:07.817" Score="5" ViewCount="265" Body="&lt;p&gt;Maybe someone knows books that are about graphic design like visual identities, colors, forms, symbols for this industry - Geology?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short - resources that are about graphic design from Geology point of view?&lt;/p&gt;&#xA;" OwnerUserId="4622" LastEditorUserId="1242" LastEditDate="2015-10-28T05:22:19.787" LastActivityDate="2015-10-28T05:22:19.787" Title="Are there books or on-line resources about graphic design for geology?" Tags="|geology|reference-request|cartography|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6706" PostTypeId="1" AcceptedAnswerId="6707" CreationDate="2015-10-12T17:57:22.290" Score="6" ViewCount="921" Body="&lt;p&gt;The webpage to &lt;a href=&quot;http://apps.ecmwf.int/datasets/data/interim-full-daily/levtype=sfc&quot; rel=&quot;noreferrer&quot;&gt;download ERA data&lt;/a&gt; includes an option called &quot;time&quot; which is intuitive, but also an option called &quot;step&quot;. I can't find an explanation of the meaning of this. It can't be a time step because it has also 0.&lt;/p&gt;&#xA;" OwnerUserId="3061" LastEditorUserId="124" LastEditDate="2015-10-12T20:03:06.023" LastActivityDate="2018-12-05T08:42:27.773" Title="What is the meaning of step in ERA reanalysis data?" Tags="|atmosphere-modelling|reanalysis|era|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6707" PostTypeId="2" ParentId="6706" CreationDate="2015-10-12T19:50:06.017" Score="6" Body="&lt;p&gt;The &quot;step&quot; is the number of hours the ERA re-forecast has been run into the future from the &quot;time&quot; of the re-analysis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, asking for ERA data with time = 12:00 and step = 0 means asking for data valid at 12:00 based on a re-analysis for 12:00. But asking for data with time = 12:00 and step = 6 means asking for data valid at 18:00, i.e. for data produced by a 6 h model run based on the 12:00 re-analysis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To fill the gaps between the analysis times one can use steps from a forward run. Forward runs are needed to get parameters like time accumulated precipitation, which would not be available from an analysis. Sometimes a combination of steps and times might be appropriate for a joint analysis of instantaneous and time averaged parameters, i.e. to stagger them correctly in time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Data valid 00:00 deviate less from the observations if they come from a 00:00 analysis compared to data from step 12 of the 12:00 analysis. But a series of steps from one initialization time should be more consistent in time compared to a series of independent analyses.&lt;/p&gt;&#xA;" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2015-10-15T20:23:19.107" LastActivityDate="2015-10-15T20:23:19.107" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="6708" PostTypeId="1" CreationDate="2015-10-12T22:06:10.187" Score="6" ViewCount="10179" Body="&lt;p&gt;Something just clicked in my head today. Rocks, by the definition I was taught, are composed of minerals which in turn are by definition not organic, so they are or were not alive. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However. Coal, bitumen, and shale are all made of organic matter. Why are they classified under sedimentary carbonaceous rocks?&lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="6129" LastEditDate="2020-05-08T06:14:37.270" LastActivityDate="2020-12-12T16:03:38.553" Title="Why is coal classified as a sedimentary rock?" Tags="|rocks|sedimentology|paleobotany|coal|" AnswerCount="4" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6709" PostTypeId="2" ParentId="6708" CreationDate="2015-10-12T23:55:32.043" Score="6" Body="&lt;p&gt;I'm not sure why you are including shale in your question, unless you are referring to carbonaceous shale, which in not coal, but shale with carbon throughout the matrix of the shale.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shale is an argillaceous rock, and argillaceous rocks are &quot;detrital sedimentary rocks&quot; [1]. They are composed of clays and the bedding plane within the shales is &quot;due to the orientation of the clay minerals&quot; [1]. Clearly a sedimentary rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Coal however, as you state in your question is derived from organic material - vegetation. The deposition of the vegetation material is analogous to the deposition of minerals that formed sedimentary rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both materials, vegetation and minerals, were transported to a location. In the case of minerals the transportation may have been a long or short distance and carried out by wind, water or gravity (mudslides). Vegetation tends to travel shorter distances than minerals but like the minerals it has traveled and it accumulates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Over time the vegetation compacts, is heated, undergoes chemical reactions and experiences a very slow form of metamorphosis and petrification.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Being composed of carbon, coal forms a carbonaceous deposit. Having been transported and accumulated in a single deposit it is sedimentary. Having undergone metamorphosis and petrification it is a rock. Consequently it is reasonable to classify coal as a carbonaceous sedimentary rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1] D. G. A Whitten with J. R. V. Brooks, &lt;em&gt;Penguin Dictionary of Geology&lt;/em&gt;, 1979 &lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-10-12T23:55:32.043" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6710" PostTypeId="2" ParentId="6708" CreationDate="2015-10-13T00:47:16.383" Score="2" Body="&lt;p&gt;Rocks are not necessarily made out of minerals. Yes, most of them are but it's not a requirement. Also, not every collection of minerals is a rock. For instance, sand is not a rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is not limited to rocks of biogenic origin. Take for example obsidian, or volcanic glass. In some cases there is not a single mineral in the rock, yet it is a rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My own personal opinion about definitions (especially in geology) is that occasionally they're useless. What happens if you have a borderline case that falls out of the strict definition? Remember - names and definitions are an artificial thing that we, humans, invented. Nature doesn't always play by our rules.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-10-13T00:47:16.383" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6711" PostTypeId="1" CreationDate="2015-10-13T01:08:27.513" Score="7" ViewCount="88" Body="&lt;p&gt;For the near-surface winds over the ocean, many model products and satellite footprints have spatial resolutions on the order of tens of kilometers. I'm interested in knowing how much the winds (both magnitude and direction) are expected to vary over tens of kilometers, at a single instant in time. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, this will depend on a variety of factors - such as if a storm is passing by, distance from the coastline, precipitation etc. I'd be happy to hear about rough numbers in all conditions, but I'm especially interested in the open ocean in both hurricane and non-hurricane conditions.&lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorUserId="4487" LastEditDate="2015-10-17T02:37:32.070" LastActivityDate="2015-10-17T02:37:32.070" Title="Spatial variability in ocean surface winds" Tags="|meteorology|ocean|wind|remote-sensing|atmosphere-modelling|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="6714" PostTypeId="2" ParentId="6705" CreationDate="2015-10-13T10:43:35.213" Score="2" Body="&lt;p&gt;There is an very detailed &lt;a href=&quot;http://ngmdb.usgs.gov/fgdc_gds/geolsymstd/download.php&quot; rel=&quot;nofollow&quot;&gt;&quot;Digital Cartographic Standard for&#xA;Geologic Map Symbolization&quot;&lt;/a&gt; by the Federal Geographic Data Committee (FGDC) including e.g. color and pattern charts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Check the main website for the latest version of the Standard, availabe in PostScript format, as pdf, or as ArcGIS10 template. &lt;/p&gt;&#xA;" OwnerUserId="3289" LastActivityDate="2015-10-13T10:43:35.213" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6715" PostTypeId="2" ParentId="6705" CreationDate="2015-10-13T11:35:23.857" Score="2" Body="&lt;p&gt;&lt;strong&gt;I don't think there are any general books on graphic design for geologists.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, there are some books about graphical standards for geological maps and sections:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://ngmdb.usgs.gov/fgdc_gds/geolsymstd/download.php&quot; rel=&quot;nofollow&quot;&gt;FGDC &lt;em&gt;Digital Cartographic Standard for Geologic Map Symbolization&lt;/em&gt;&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://nora.nerc.ac.uk/3221/1/RR01001.pdf&quot; rel=&quot;nofollow&quot;&gt;British Geological Survey &lt;em&gt;Standard Cartographic Index&lt;/em&gt;&lt;/a&gt; [PDF]&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.ga.gov.au/image_cache/GA17066.pdf&quot; rel=&quot;nofollow&quot;&gt;Australian Bureau of Mineral Resources symbols guide&lt;/a&gt; [PDF]&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://w3.energistics.org/Shell_Standard_Legend/STANDLEG.PDF&quot; rel=&quot;nofollow&quot;&gt;Shell's &lt;em&gt;Standard Legend&lt;/em&gt;&lt;/a&gt; [PDF]&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;For colour, you might be interested in the &lt;a href=&quot;http://www.pantone.com/munsell-rock-color-chart&quot; rel=&quot;nofollow&quot;&gt;&lt;em&gt;Munsell Rock Color Chart&lt;/em&gt;&lt;/a&gt;, though it's for describing actual rocks, not making geological maps. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are lots of books on cartographic design, for example:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;em&gt;Cartography: Thematic Map Design&lt;/em&gt;, by Dent et al (2008), ISBN 978-0072943825 — &lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/0072943823&quot; rel=&quot;nofollow&quot;&gt;Amazon&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;em&gt;GIS Cartography: A Guide to Effective Map Design&lt;/em&gt;, by Gretchen Peterson (2014), ISBN 978-1482220674 — &lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/1482220679&quot; rel=&quot;nofollow&quot;&gt;Amazon&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;The Map as Art: Contemporary Artists Explore Cartography, by Harmon &amp;amp; Clemens (2010), ISBN 978-1568989723 — &lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/1568989725&quot; rel=&quot;nofollow&quot;&gt;Amazon&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Finally, there are &lt;a href=&quot;http://www.edwardtufte.com/tufte/books_be&quot; rel=&quot;nofollow&quot;&gt;Edward Tufte's amazing books&lt;/a&gt;, a must-read for anyone interested in the design of scientific graphics of any kind. &lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-10-13T11:35:23.857" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6716" PostTypeId="2" ParentId="6699" CreationDate="2015-10-13T13:07:40.010" Score="3" Body="&lt;p&gt;If it is a predator's coprolite you should expect to see bone fragments. Coprolites from herbivores? I would expect them to be pretty rare as there is almost nothing likely to fossilize.&#xA;As for meteorites, they come in many forms: stones, irons, palasites, chondrites. The candidates need a good description. A weathered heat ablation surface is the most obvious characteristic to look for. In all cases the rock identification is best achieved with a polarizing microscope, unless it is something very obvious like an iron meteorite. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-13T13:07:40.010" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6717" PostTypeId="2" ParentId="683" CreationDate="2015-10-13T13:55:45.557" Score="5" Body="&lt;p&gt;The question seems to assume that the increase or decrease in mountain elevation is consistent and uniform, which it isn't. The Indian and Tibetan tectonic plates are converging in a NNE-SSW direction at an overall mean rate of between 26 and 36 mm per year. However, most of the time this convergence is taken up as static strain energy, released as elastic rebound during infrequent earthquakes. Moreover, Everest is at the northern boundary of the collision zone. Most of the deformation and strain energy is absorbed further south in a complex imbricate structure of shallow angle over-thrusts of the Tibetan over the Indian plates. If the last Nepalese earthquake is anything to go by, the vertical component of the convergence is about a third. That is, about 8 to 12 mm per year, of which we may assume that at least 3/4 takes place as deformation further south. That leaves a maximum mean uplift of between 6 and 9 mm a year at Everest, with a probability that in reality it is somewhat less. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Satellite measurements haven't been undertaken for long enough for us to get a long-term handle on uplift rate. There are also complicating factors: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;For a mountain mass of such a size there is likely to be isostatic movement caused by slow buckling of the crust in relation to the 'soft' upper mantle. &lt;/li&gt;&#xA;&lt;li&gt;Earthquakes can both raise and lower the mountain according to the geometry of motion. In the last earthquake Kathmandu rose by a metre, but Everest fell by several centimeters. There is no guarantee that the next quake will do the same. A quake further south in the Himalayas is likely to cause back-tilting (and hence lowering) of the Everest massif, whereas a quake with an epicenter close to Everest could raise it by several metres.&lt;/li&gt;&#xA;&lt;li&gt;The summit is covered by a variable thickness of snow, typically from 1 to 4 metres, so there is a discrepancy between the height of the actual summit (with snow) and the bare rock. &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="543" LastEditDate="2015-10-13T15:51:43.767" LastActivityDate="2015-10-13T15:51:43.767" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6718" PostTypeId="2" ParentId="6695" CreationDate="2015-10-14T00:14:16.333" Score="4" Body="&lt;p&gt;I don't know much about Scandinavia in the 1500's, and in particular, how much was forested. However, one can say that the whole area was previously glaciated, with much of the topsoil being eroded away by ice, so soils generally tend to be thin, immature, sandy and nutrient poor. We do know that conifers predominated, leaving a soil-litter of pine needles. This latter has a high cation exchange capacity that leads to acid flushes whenever it rains after a long dry period. This acidity tends to leach out nutrients and adds small concentrations of toxic metals. These conditions do not help the soil's fertility. In addition, the valley floors often accumulate peat, hence high organic carbon and acidity. &#xA;The geology of Scandinavia is complex, and difficult to generalize. Periglacial outwash in Sweden and Denmark would have given rise to some fertile areas, especially where there is limestone to counteract the tendency to acidity. So compared to Russia, Scandinavian soil and agricultural potential is more variable.&#xA;As regards climate, coastal Norway is much warmer than either eastern Scandinavia and Russia on account of proximity to the Gulf Stream Drift. It also has higher rainfall, so the effective growing season is longer. Northern Scandinavia and Russia have close to 24 hours sunlight per day in high summer, so one wonders whether two growing seasons per year for some crops might be feasible? Are there any agronomists out there who can advise on this question?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-14T00:14:16.333" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6719" PostTypeId="2" ParentId="3025" CreationDate="2015-10-14T03:36:52.917" Score="0" Body="&lt;p&gt;Cirrus cloud is already widespread in the tropics, and is slowly spreading polewards in response to global warming. If the air temperature is around -40 deg C, as it commonly is at the cruising altitude of modern jets, then ice crystals form almost immediately as the water vapour crystallizes around nuclei (soot particles from the burnt aviation fuel). High level winds then disperse the ice crystals to form additional cirrus. The effect is pretty small, with high-level contrail cirrus covering about 0.1% of the global surface area, compared to about 20 to 25% coverage that was there in the first place. The effect &lt;em&gt;seems&lt;/em&gt; larger because most high level jet traffic is at mid latitudes. See &lt;a href=&quot;http://www.flightradar24.com/27.36,-64.11/3&quot; rel=&quot;nofollow&quot;&gt;http://www.flightradar24.com/27.36,-64.11/3&lt;/a&gt; (but beware - this page is addictive).&#xA;The next question is 'what effect does increased cirrus have on the global heat balance'? Ice crystals reflect incoming solar radiation, but also reflect outgoing thermal radiation - acting as a kind of Greenhouse blanket. According to theory, the latter should slightly exceed the former, thus constituting a positive feedback to global warming. In the tropics the cirrus is known to cause slight warming, but at other latitudes the jury is still out. The ice crystals in cirrus vary according to size, shape, orientation with respect to incoming solar radiation, cloud density and cloud thickness. Also, it is known that tropical, mid-latitude and polar cirrus all behave differently, so there is still some research required to get a good handle on the global effect of cirrus in general, and contrails in particular. Liou gives a good summary of current (?) knowledge in &lt;a href=&quot;http://people.atmos.ucla.edu/liou/Cirrus_&amp;amp;_Climate.pdf&quot; rel=&quot;nofollow&quot;&gt;http://people.atmos.ucla.edu/liou/Cirrus_&amp;amp;_Climate.pdf&lt;/a&gt; &#xA;This is an area of active research. Does anyone have a more up-to-date assessment?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-14T03:36:52.917" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6721" PostTypeId="2" ParentId="6698" CreationDate="2015-10-14T04:24:51.003" Score="12" Body="&lt;p&gt;Yes, it is real. Whoever took the photo, congratulations on a very fine image.&#xA;I have never seen this texture on such a scale, but something similar can be achieved in the laboratory by creating a bubble membrane of pure super-cooled water and blowing a few dust nuclei onto the surface. A comparable geometry appears very rapidly. The size of the ice crystals are difficult to judge without any feature to give scale, but they seem to be exceptionally large trigonal terminations. We have all seen snowflakes of hexagonal symmetry, but under metastasble conditions with rapid crystal growth, stacking disorders tend to occur in the crystal lattice, yielding a trigonal rather than hexagonal symmetry. See, for example, &lt;a href=&quot;http://www1.lsbu.ac.uk/water/ice_phases.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;The ice phases of water&lt;/a&gt;. This is an unusual polymorph of ice, and I cannot see how it could be achieved except through sudden seeding of very pure water. Perhaps stratified freshwater lakes, in still air, on a very cold night, with a surface of previously melted ice (i.e. pure water), and subject to a sudden windy gust of nucleation particles would provide the right conditions?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="725" LastEditDate="2017-03-25T12:23:07.930" LastActivityDate="2017-03-25T12:23:07.930" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6722" PostTypeId="2" ParentId="2570" CreationDate="2015-10-14T04:55:16.047" Score="1" Body="&lt;p&gt;The bolide depicted in the film seems to have been modeled upon the Chixculub meteor that impacted Yukatan, and created the K-T extinction event. Both the film and Chixculub were about 11 kilometers in diameter. This would result in a roughly $10^5$ Gtonne impact explosion - with some variation depending upon the density of the bolide, and the orientation with respect to the Earth's orbital vector, and hence the velocity of impact. The blast radius would be several thousand kilometers - actually about 7000 kilometers on a theoretical plane surface, but somewhat less due to the curvature of the Earth. So, sorry Atlanta, irrespective of whether the tsunami reaches your fine city, its curtains for you! :-) &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="6" LastEditDate="2017-05-17T17:18:36.250" LastActivityDate="2017-05-17T17:18:36.250" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6723" PostTypeId="1" CreationDate="2015-10-14T07:06:12.173" Score="6" ViewCount="2392" Body="&lt;p&gt;As &lt;a href=&quot;https://en.wikipedia.org/wiki/Nastapoka_arc&quot; rel=&quot;nofollow&quot;&gt;wikipedia&lt;/a&gt; says, the Nastapoka arc is a geological feature located on the southeastern shore of Hudson Bay, Canada.&lt;br /&gt;&#xA;(&lt;a href=&quot;http://ottawa-rasc.ca/wiki/index.php?title=Odale_articles_hudsonbayarc&quot; rel=&quot;nofollow&quot;&gt;Other description with picture at the Royal Astronomical Society of Canada&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No signatures of an impact event was found. However, 'A hole was drilled on Neilson Island, within the arc, in 1962. The core lacked any evidence of shock metamorphism, but one hole was not regarded as sufficient to settle the question of possible meteoric origin. '&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is that possible that the impact material was buried deep in the past hundreds of thousands of years?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is other believable mechanism that can form that shape?&lt;/p&gt;&#xA;" OwnerUserId="4632" LastEditorUserId="1411" LastEditDate="2015-10-16T17:36:05.700" LastActivityDate="2020-05-28T19:41:06.440" Title="How was Nastapoka arc formed?" Tags="|geology|meteorite|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6724" PostTypeId="1" AcceptedAnswerId="6738" CreationDate="2015-10-14T15:14:46.913" Score="8" ViewCount="347" Body="&lt;p&gt;According to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Snowball_Earth&quot;&gt;snowball Earth&lt;/a&gt; theory, all of Earth froze over at least once (possibly twice) in the far past. However, Wikipedia says that there are opponents of the theory who state that tropical portions of the oceans were not entirely covered. These responses have been motivated both by sedimentary deposits (also used by proponents of the theory) and by computer simulations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any consensus as to whether or not the surface of Earth's oceans froze over entirely during either of the two main snowball Earth periods (~ 650 million years ago and &lt;a href=&quot;http://en.wikipedia.org/wiki/Huronian_glaciation&quot;&gt;~2.1 billion years ago&lt;/a&gt;)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To be clear, my question is about surface ice, not underwater freezing.&lt;/p&gt;&#xA;" OwnerUserId="1399" LastEditorUserId="1411" LastEditDate="2015-10-16T15:18:29.317" LastActivityDate="2016-04-26T11:12:50.003" Title="Did the surfaces of the oceans freeze over entirely during the snowball Earth periods?" Tags="|climate|paleoclimatology|ice-sheets|sea-ice|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="6725" PostTypeId="1" CreationDate="2015-10-15T00:27:37.667" Score="-6" ViewCount="686" Body="&lt;p&gt;The full question is: Is it possible that the recent, successive, long droughts from Australia to the West Coast of both American continents are signs of epic crust failure?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question is aimed specifically at the possible link between droughts at those specific areas and the weakening/loosening of lateral stress between tectonic plates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reasoning is based on the following observations:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The crust is not rooted in the mantle, and is cut in numerous crustal plates. Tectonic plates are held in place like an arch, so the gravity and lateral stress and friction are the main forces holding them up. Mantle flow provides uneven support to continental plates and is actually the main destabilizing force according to current theories.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Based on the idea above, if humans dig up too much underground materials around the fault lines, the edges of the fault lines are weakened: there is less material to keep up adequate lateral stress. Then, the soil around the softer/weaker side of the fault will deform and be compacted, or fail and result in earthquake. Deformation/compaction and fault failure do happen naturally too, but humans may have extracted too much underground resources for the natural healing process to catch up with the rate of weakening at the edges. It is known that the fault of the West Coast is lacking stress and the soil is deformed in the Amos et al. (2014) study. If this keeps up, the arch structure of the crust will crumble down catastrophically, and in chain reaction too. And it doesn't take &quot;much&quot; edge weakening to fail an arch.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Additional information: The Amos study says that California lost 160 KM^3 of groundwater in the past 150 years. Now, add the amount of oil extracted. Then, add the amount of oil, water, minerals that are extracted along the West Coast of North and South America, Australia, Japan, South East Asian Islands. This should give some idea of how big are the holes human dug underground.&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;&lt;p&gt;The scenario may correspond with the Pacific plates. There are numerous oil, and water extracting operations all around the Pacific. After decades of intensive and continuous resource extractions, it may be showing terminal signs of  the natural healing process failing to catch up with the rate of weakening at the edges. First, there are quite a few very strong earthquakes concentrated in the last ten years (&lt;a href=&quot;http://earthquake.usgs.gov/earthquakes/world/10_largest_world.php&quot; rel=&quot;nofollow&quot;&gt;http://earthquake.usgs.gov/earthquakes/world/10_largest_world.php&lt;/a&gt;). This alone may be trivial since the Pacific Ring of Fire is well known to churn out earthquakes. However, combined with the recent persistent droughts of Australia, Chile, US (especially California), and this year, Canada, the situation may be really concerning.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Droughts alone can be caused by weather patterns. Climate change can cause it too, but it is a global factor, as opposed to more localized factor such as weather patterns. However, I think that underground processes can also cause drought. Aquifers can store a lot of heat, so the lack of underground water means  that the geothermal energy will dissipate into the surrounding soil, basically slowly baking it. Less water also means that the soil is more prone to compression. Compression, especially continuous, even if it's slow, also generates heat. Oil reservoirs are also similar, but since oil is more reactive to heat by transforming into gas, and continuously extracted by humans, their pore pressure varies more. The presence of oil reservoirs around the fault lines may serve as springs. By extracting oil/gas, humans lessen the expansion force of those liquid and gas and reduce the pore pressure, which stabilizes the fault line. But in the long term, as is the case now, the reality is that there will be not enough oil to provide adequate pore pressure/lateral stress/counter-compression force. This may be the cause of the recent frequent strong earthquakes; the plates are loosening. Eventually, all the edges of the Pacific ring will all fail in an epic catastrophe, as the arch structure of the crust crumbles.  Also, by removing oil, it liberates more space for gas to form. Gas is more compressible and heated by compression; it is another source geothermal heat. It is like a bike air pump/air suspension system. The idea is that the excess of geothermal energy causes surface water to dry out faster.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Another possibility is that the fault line of the West American continent is already caving in and is dipping deeper/entering into more contact with the mantle. The mantle is a way stronger source of heat, and without adequate of underground heat absorbers, the surface soil becomes baked. I think that it's also the cause of the Blob (&lt;a href=&quot;https://en.wikipedia.org/wiki/The_Blob_%28Pacific_Ocean%29&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/The_Blob_%28Pacific_Ocean%29&lt;/a&gt;). The heat of the soil is escaping into the ocean, forming the Blob. Combined with El Nino, it worsens the drought.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;In summary, humans have dug up resources around active fault lines of the Pacific for more than a century. The weakened soil/plate edges lead to excessive geothermal energy affecting the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So yeah, in the end, is it possible that the recent droughts are signs of epic crust failure?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please kindly point out if my observation/logic makes sense and/or may correspond with reality.&lt;/p&gt;&#xA;" OwnerUserId="4630" LastEditorUserId="4630" LastEditDate="2015-10-16T00:56:27.100" LastActivityDate="2017-02-17T01:23:08.790" Title="Is it possible that the recent droughts are signs of epic crust failure?" Tags="|geophysics|earthquakes|groundwater|petroleum|drought|" AnswerCount="1" CommentCount="8" ClosedDate="2015-10-15T15:07:11.273" ContentLicense="CC BY-SA 3.0" />
  <row Id="6726" PostTypeId="2" ParentId="6725" CreationDate="2015-10-15T08:07:29.180" Score="13" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is it possible that the recent droughts are signs of epic crust failure?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;No&lt;/strong&gt;. Even though your 5 points do not make much sense, I'll try to answer it anyway.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;There are no continental plates. There are lithospheric plates, consisting of both continental crust and oceanic crust. While it is true that arches in construction (buildings and bridges) are held &quot;up&quot; by lateral stress and gravity, lithospheric plates are not arches. Directly below the crust there exists a mantle, made out of a ductile, yet solid, material. The crust can't just &quot;fall down&quot;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Movements that occur along plate boundaries are controlled by tectonic forces much larger than anything that we humans can even think of affecting. While it is true that some seismic activity can be explained by extraction of resources, these are usually up/down movements. Thus, extracting oil from the Los Angeles area will not cause the movement along the San Andreas fault to move any slower or faster.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;So yes, there are large earthquakes, including recently, in the ring of fire. I don't understand how is this supposed to be related to droughts. There earthquakes are controlled by forces deep down in the Earth. Furthermore, the plate boundaries are under kilometres of ocean water. Whether or not there is rain on the continents is irrelevant.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Gas is not formed simply by evaporation of oil. Releasing pressure does not turn oil to gas. This is a long process that takes geological time spans. Deep water that may be affected by geothermal heat has long residence times - hundreds and thousands of years. A few years of drought will not do much for it. Most of the oil and gas are being produced in sedimentary basins, far away from plate boundaries. These have nothing to do with earthquakes near these fault lines. Even the fields that are somewhat close to fault boundaries - the amount of oil or gas that's actually in the ground is negligible relative to how much rock there is. It's not like there are lakes or pools of oil and gas. It's all in between the grains of whatever sedimentary rock is there (usually sandstone).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The term you are looking for is &lt;em&gt;subduction&lt;/em&gt;. Yes, there is some subduction activity (otherwise we wouldn't have volcanoes such as Mt St Helens). This is nothing new, and again, this has nothing to do with droughts.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2017-02-17T01:23:08.790" LastActivityDate="2017-02-17T01:23:08.790" CommentCount="19" ContentLicense="CC BY-SA 3.0" />
  <row Id="6727" PostTypeId="2" ParentId="2240" CreationDate="2015-10-15T11:35:06.243" Score="0" Body="&lt;p&gt;There are several interesting components in soil:  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The carbon content, mostly in the form of &lt;a href=&quot;https://en.wikipedia.org/wiki/Humic_acid&quot; rel=&quot;nofollow&quot;&gt;humic acids&lt;/a&gt; - a proxy for how well the soil an store nutrients and water and for wether there's a living soil microbiome (earthwormes etc.). Soil carbon is also removed by biological processes outside of special circumstances like peat foramtion. Carbon is added by decaying plant matter and other organic matter, like faeces of animal (wether natural or manure applied as fertilizer)  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The macronutrient content, what we think of as fertilizer - usually N, P, K, (and to a lesser extent) S are considered macronutrients that plants need. There is also the question on how available those nutrients are.  Macronutrients are added as fertilizer. Macronutrients that come as part of organic matter (e.g. N in proteines) must first be digested by something. This is why earthworms and the like are important. Macronutrients can be washed out and aer used by plants.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Micronutrients - trace elements, salts etc. that plants need. Again, it is important to understand that not so much the total amount in a given volume of earth is interesting but the amount actually available to a plant (Mg tied up in the middle of some rock won't help). I think these cycle like macronutrients, but the slow breakdown of sand and rock is also an important source. But this is a slow process. On intensivly used fields, these will be added in addition to fertilizer. This gives you a hint that the processes supplying micronutrients happen slowly. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So if you think of soil as the sum of these three categories you can look at how fast or slow each is replenished and used. FArmers will watch for the nutrient balances as well as for the carbon balance of their fields.&lt;br&gt;&#xA;However all of these influence each other, soil is really complex. While you can argue that soil is renewable since in some cases all three broad categories of stuff will be replenished eventually, IMO this misses the point how slowly this happens. It also misses the more important point that soil is not simply a mixture of stuff but ideally a living system where things happen. &lt;/p&gt;&#xA;" OwnerUserId="117" LastActivityDate="2015-10-15T11:35:06.243" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6728" PostTypeId="1" AcceptedAnswerId="6729" CreationDate="2015-10-15T13:36:48.233" Score="4" ViewCount="363" Body="&lt;p&gt;I would like to purchase a/some books which are really good and practical references to get into the oceanic data (wave heights,currents and sea level) treatment and statistical analysis, coming from in-situ instruments (buoys, ADCPs, etc...) or from simulation models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It would be great if such book has also some connection with some programming language (Python/R for example).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyone could help?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks. &lt;/p&gt;&#xA;" OwnerUserId="492" LastActivityDate="2015-10-15T14:06:30.927" Title="Best book/s of oceanic data treatment and analysis?" Tags="|oceanography|sea-level|waves|ocean-currents|ocean-models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6729" PostTypeId="2" ParentId="6728" CreationDate="2015-10-15T14:06:30.927" Score="3" Body="&lt;p&gt;My personal best is the Emery &amp;amp; Thomson &lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/0123877822&quot; rel=&quot;nofollow&quot;&gt;&quot;Data Analysis in Physical Oceanography&quot;&lt;/a&gt;. You can find some used versions of the previous editions for a much cheaper price. If you are able to manage the methods described in that book, you will be in good shape. The only one of your requirements it doesn't do is the coding part. If I had to choose one book, I would definitely buy this one and then search for code elsewhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want a book that provides some code and explains some of the analysis, you could try the Malek-Madani &lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/158488830X&quot; rel=&quot;nofollow&quot;&gt;&quot;Physical Oceanography: A Mathematical Introduction with Matlab&quot;&lt;/a&gt;. It is theoretical rather than focus on data analysis. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A relatively cheap book with some useful codes, not specific to Oceanography is Middleton &quot;&lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/0133935051&quot; rel=&quot;nofollow&quot;&gt;Data Analysis in the Earth Sciences using Matlab&lt;/a&gt;&quot;. Some of it might be slightly outdated, but still useful.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-10-15T14:06:30.927" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6730" PostTypeId="2" ParentId="6698" CreationDate="2015-10-15T14:13:35.540" Score="9" Body="&lt;p&gt;This picture was taken in what seem to be a small pond, of very calm water. It seem that in ideal conditions, implying but not limited to :&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;absence of winds&lt;/li&gt;&#xA;&lt;li&gt;clean water eg: no nuclei to provide an anchor for crystal formation&lt;/li&gt;&#xA;&lt;li&gt;low temperature gradient between air and watrer (air almost near 0 °C and very slowly falling)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;ice grain can grow quite large.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This &lt;a href=&quot;http://www.nrcresearchpress.com/doi/pdfplus/10.1139/t71-004&quot;&gt;paper&lt;/a&gt; discusses the matter of ice classification for lakes and river. &lt;strong&gt;Fig. 1&lt;/strong&gt; display a flow chart on possible paths for ice formation - I would interpret that the ice formation followed the left path, from fresh water, to calm water toward plate-ice, followed by undisturbed growth to ice sheet, and ice cover.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To cite how the primary ice would form on the pond (Michel and Ramseier, 1971) : &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;On&#xA;  a calm surface the primary ice is an ice skim&#xA;  which grows horizontally in the supercooled&#xA;  layer and is a few tenths of a millimeter thick. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;For a calm surface and a small temperature gradient, it is possible to see forming very large to giant (up to meter sized) grains in ice. Later in the discussion :&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Many of the platelets or discoids&#xA;  develop into dendrites, and the interaction of&#xA;  the dendrites causes the crystal boundaries to&#xA;  be very angular and elongated in shape. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Michel, B. &amp;amp; Ramseier, R. O. Classification of river and lake ice Canadian Geotechnical Journal, 1971, 8, 36-45&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following is a reference on the matter in my opinion:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shumskii, Petr Aleksandrovich. Principles of structural glaciology: the petrography of fresh-water ice as a method of glaciological investigation. Dover Publications, 1964.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2015-10-15T14:13:35.540" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6733" PostTypeId="1" AcceptedAnswerId="6747" CreationDate="2015-10-15T21:55:38.980" Score="5" ViewCount="90" Body="&lt;p&gt;Does anyone know why every month there are updates to the RSS historical atmospheric data? How can data that is 10 years old need adjusting every month?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For instance, here's the difference in data points from July 2015 and October 2015 for the total tropospheric.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fH3ON.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fH3ON.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4644" LastEditorUserId="4487" LastEditDate="2015-10-18T02:41:16.637" LastActivityDate="2015-10-18T02:41:16.637" Title="Remote Sensing System (RSS) historical atmospheric data continually updated" Tags="|atmosphere|remote-sensing|open-data|troposphere|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="6734" PostTypeId="2" ParentId="4535" CreationDate="2015-10-15T22:12:18.957" Score="2" Body="&lt;p&gt;The answers posted thus far have correctly pointed out that natural life would cease to exist without photosynthesis provided by the sun, and natural heat sources from the Earth would only be enough to sustain some very simple lifeforms, and even that is a big maybe.  However, there is one other possibility that I have not seen mentioned, which is the influence of man-made technology. Technically life could survive on Earth in an artificial environment if there were (for instance) man-made power generators that warmed areas (probably underground for insulation).  Clearly all life would be dependent on technological processes that would fail at some point and the likelihood of having replacement parts and mechanics is slim at best.  But, the advancements in automated artificial intelligence could one day take this concept much further.  Furthermore, if there were an external source of energy that could be used (e.g. if we had much more skill with space travel), that energy could be transported to Earth and used in some way to allow life to exist in a highly controlled artificial environment.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2015-10-16T14:50:42.157" LastActivityDate="2015-10-16T14:50:42.157" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6735" PostTypeId="2" ParentId="4498" CreationDate="2015-10-15T22:22:29.580" Score="2" Body="&lt;p&gt;It is the warmth of the atmosphere that you feel on your skin.  The atmosphere is warmed from the surface of the Earth.  Visible light from the sun hits the surface of the Earth and some of it is absorbed, causing the Earth's surface to warm, which is re-radiated as infrared light and is then blanketed by our atmosphere.   Without the atmosphere, the temperature of Earth's surface would be much colder and have a much more dramatic diurnal cycle.  &lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2015-10-15T22:22:29.580" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6736" PostTypeId="2" ParentId="4535" CreationDate="2015-10-15T23:12:40.647" Score="4" Body="&lt;p&gt;Popular science has a good write up on this. In short, everything on the surface is doomed in a year or two. Life in the Oceans would last several hundred thousand years. After that, it's probably just microorganisms living near vents at the bottom of the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.popsci.com/node/204957&quot; rel=&quot;nofollow&quot;&gt;http://www.popsci.com/node/204957&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4644" LastActivityDate="2015-10-15T23:12:40.647" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6737" PostTypeId="1" CreationDate="2015-10-16T13:13:29.430" Score="6" ViewCount="203" Body="&lt;p&gt;Since tectonic plates are held together by lateral stress, friction, and gravity, and the Earth is a sphere, they work just like a full-circle arch or full-sphere dome. So can the crust be compared to an arch?&lt;/p&gt;&#xA;" OwnerUserId="4630" LastEditorUserId="4487" LastEditDate="2015-10-25T00:26:38.030" LastActivityDate="2015-10-25T00:26:38.030" Title="Can the crust be compared to an arch?" Tags="|geophysics|plate-tectonics|mantle|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6738" PostTypeId="2" ParentId="6724" CreationDate="2015-10-16T14:49:28.923" Score="6" Body="&lt;p&gt;By looking at the recent literature on the question, I see neither a consensus or a definitive answer on the extent of the snowball earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the Neoproterozoic Snowball Earth event is more recent, there seem to be more evidences available and therefore more relevant research on this event than the 2.1 BY one - and will consider in the following only the latest event.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/nature/journal/v405/n6785/abs/405425a0.html&quot;&gt;This paper&lt;/a&gt; suggest that the ice cover was likely global but some open water would have persisted in equatorial regions where complex life would have been able to survive during the glaciation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://authors.library.caltech.edu/36446/&quot;&gt;This other paper&lt;/a&gt; suggest that glaciogenic sequences (sedimentary rocks containing  sediments deposited by glacier actions, for modern analog non-consolidated examples see till or moraine) in high latitudes (North) contains fragments of carbonates which was likely formed near the equatorial zone and somewhat transported by glacier action.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/nature/journal/v428/n6980/abs/nature02408.html&quot;&gt;This yet another paper&lt;/a&gt; modeled how glaciation likely reach the equator, where &lt;a href=&quot;http://www.nature.com/nature/journal/v409/n6818/abs/409306a0.html&quot;&gt;this paper&lt;/a&gt; suggest that open sea must exists.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencemag.org/content/281/5381/1342.short&quot;&gt;Other papers&lt;/a&gt; suggested that once a significant part of the Earth was covered by glaciers, albedo effect significantly cooled the planet until some kind of massive volcanic eruption interrupted the cycle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only consensus I figure is that it most likely happened (a late Proterozoic Snowball Earth Event) but it still remain to be seen if a thick cover of ice '&lt;a href=&quot;http://apod.nasa.gov/apod/ap150920.html&quot;&gt;a la Encalade&lt;/a&gt;' covered the Earth at one time or another, or not.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2015-10-16T14:49:28.923" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6739" PostTypeId="2" ParentId="6723" CreationDate="2015-10-16T16:15:40.557" Score="4" Body="&lt;p&gt;Gravity anomalies surveys are used to understand the nature of the crustal material. Positive anomalies, or higher gravity than surroundings suggests higher density (heavier) material, (iron, metallic composition) where lower some lighter alternatives. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good example of this is the &lt;a href=&quot;http://www.passc.net/EarthImpactDatabase/chicxulub.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chicxulub impact&lt;/a&gt;. The &lt;a href=&quot;http://miac.uqac.ca/grav-3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;map of gravity anomalies&lt;/a&gt; show the crater quite clearly, even if it is buried under thick layers of sea sediments or surface (Yucatan, MX).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, Nastapoka arc is harder to define using similar methods. This &lt;a href=&quot;http://www.geotop.ca/pdf/darbyshireF/Eaton_and_Darbyshire_Tectonophysics_InPress.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;recent paper (PDF)&lt;/a&gt; (now published &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0040195109005034&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;) discusses that it may have more to do with crustal dynamics than an impact. Nevertheless they present an  interesting gravity map of the site (See figure), where any links to an impact in this area would not be obvious.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IqInq.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IqInq.jpg&quot; alt=&quot;interesting gravity map&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is true that major glacial activity occurred repeatedly during the Pleistocene east of the Hudson Bay (eg: Laurentidian Ice Sheet sweeping again and again), but yet the Chicxulub impact was subject to many factors of erosion as well since its formation near the K-T boundary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Still these kind of surveys indicate the nature of the material in the crust - so even if several glaciations impacted the Nastapoka arc area, there would be some kind of patterns still present indicating heavy metals (Chondrite or anything typical of an impact, iron or circular metamorphism).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To conclude, unless other surveys suggests an alternative interpretation path in the future, few evidences strongly support the theory of an ancient impact at Nastapoka.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2015-10-16T16:15:40.557" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6740" PostTypeId="1" AcceptedAnswerId="6742" CreationDate="2015-10-16T18:51:07.487" Score="3" ViewCount="592" Body="&lt;p&gt;Is there a website that contains the maps of atmospheric pressure and wind speeds for specific climatic events such as hurricanes day after day ?&lt;/p&gt;&#xA;" OwnerUserId="4650" LastEditorUserId="4487" LastEditDate="2015-10-25T00:27:15.810" LastActivityDate="2015-10-25T00:27:15.810" Title="Website that contains the maps of atmospheric pressure and wind speeds" Tags="|meteorology|atmosphere|wind|tropical-cyclone|severe-weather|" AnswerCount="1" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6741" PostTypeId="2" ParentId="6737" CreationDate="2015-10-16T18:54:59.937" Score="7" Body="&lt;p&gt;An arch is a poor analogy for tectonic plates.  The lithosphere is  supported beneath by the mantle, unlike an arch which is unsupported beneath.  If the lithospheric plates were only held together only by lateral stress, friction with surrounding plates and gravity, how would they move relative to each other?  How would forces at the plate interfaces vary?  How would subduction work without the whole thing falling apart?  I am not a geologist but I cannot see how this arrangement would work.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mantle &quot;fluid&quot; that sits underneath the lithosphere convects and drives plate motion.  It accepts subducting plates and emits new oceanic crust along the mid-oceanic ridges.  The support everywhere underneath the lithosphere by the asthenosphere makes an arch a poor representation for the physics at work.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, you are correct that at the tectonic plate edges there is lateral stress and friction and that the whole plate is subject to gravity.  What you are missing is  that the crust is everywhere supported underneath.  An arch relies on the lateral stress to stay standing while tectonic plates do not.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-10-16T18:54:59.937" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6742" PostTypeId="2" ParentId="6740" CreationDate="2015-10-16T23:56:49.507" Score="4" Body="&lt;p&gt;Check out this beta data portal from the Cooperative Institute for Meteorological Satellite Studies / University of Wisconsin-Madison&#xA;CIMSS Tropical Cyclones&#xA;Data Archive &lt;a href=&quot;http://tropic.ssec.wisc.edu/archive/&quot; rel=&quot;nofollow&quot;&gt;http://tropic.ssec.wisc.edu/archive/&lt;/a&gt;  .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, my favorite source of information is the Regional and Mesoscale Meteorology Branch (RAMMB) of NOAA/NESDIS &lt;a href=&quot;http://rammb.cira.colostate.edu/products/tc_realtime/&quot; rel=&quot;nofollow&quot;&gt;http://rammb.cira.colostate.edu/products/tc_realtime/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And there are good summaries here:&#xA;&lt;a href=&quot;https://www.tropicalstormrisk.com/hislink.html&quot; rel=&quot;nofollow&quot;&gt;https://www.tropicalstormrisk.com/hislink.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and another good general source of information is from the National Hurricane Center &lt;a href=&quot;http://www.nhc.noaa.gov/data/&quot; rel=&quot;nofollow&quot;&gt;http://www.nhc.noaa.gov/data/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2015-10-16T23:56:49.507" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6743" PostTypeId="1" AcceptedAnswerId="6744" CreationDate="2015-10-17T13:26:52.193" Score="6" ViewCount="72" Body="&lt;p&gt;I've noticed this term in a book about Pleistocene East Europe. It's apparently a soil which was formed during the interstadials, but that's all my book says, and I can't find much more on the internet. So what more can be said about frost-gley, preferably with sources?&lt;/p&gt;&#xA;" OwnerUserId="4652" LastEditorUserId="4487" LastEditDate="2015-10-17T22:11:54.367" LastActivityDate="2015-10-17T22:11:54.367" Title="What's a frost-gley?" Tags="|paleoclimatology|soil|ice-age|soil-moisture|permafrost|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6744" PostTypeId="2" ParentId="6743" CreationDate="2015-10-17T15:07:14.623" Score="6" Body="&lt;p&gt;A frost-gley is a waterlogged permafrost soil. IOW, a &lt;a href=&quot;http://en.wikipedia.org/wiki/Gleysol&quot;&gt;gleysol&lt;/a&gt; that has undergone &lt;a href=&quot;http://en.wikipedia.org/wiki/Cryoturbation&quot;&gt;cryoturbation&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="4487" LastActivityDate="2015-10-17T15:07:14.623" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6746" PostTypeId="1" AcceptedAnswerId="6765" CreationDate="2015-10-17T21:50:14.547" Score="3" ViewCount="113" Body="&lt;p&gt;I am reading this &lt;a href=&quot;http://www.researchgate.net/profile/Nicolas_Sifakis/publication/228783674_Quantitative_mapping_of_air_pollution_density_using_Earth_observations_a_new_processing_method_and_application_to_an_urban_area/links/0c96051b56b0784882000000.pdf&quot; rel=&quot;nofollow&quot;&gt;paper&lt;/a&gt; about deriving AOT and I have found this &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;This grid dimension proved to be an optimum compromise: &#xA;It is large enough to include some visible ground structure and sufficiently&#xA;small to allow consideration of a homogeneous atmosphere inside the grid cells&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;What does it mean...  homogeneous atmosphere inside grid cells? &lt;/p&gt;&#xA;" OwnerUserId="4463" LastEditorUserId="4487" LastEditDate="2015-10-28T06:58:09.163" LastActivityDate="2015-10-28T06:58:09.163" Title="Quantitative mapping of air pollution Sifakis and Paronis" Tags="|geophysics|atmosphere|climate|atmosphere-modelling|air-pollution|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6747" PostTypeId="2" ParentId="6733" CreationDate="2015-10-18T01:34:38.963" Score="4" Body="&lt;p&gt;Being remote sensing, algorithms for inverting the raw data to get physical quantities may be improving with time. Perhaps a slight adjustment in algorithm or calibration happened between July and Sept of this year. However you would expect this to introduce a systematic adjustment, not a scatter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One might reasonably wonder why the data is steady before 1999. That may be because there were fewer (or different) remote sensor parameters measured then, or the data wasn't as precise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another possibility is that the calculation was simply done more precisely, and you are looking at the elimination of round off errors, or different round offs.&lt;/p&gt;&#xA;" OwnerUserId="4487" LastActivityDate="2015-10-18T01:34:38.963" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6749" PostTypeId="1" CreationDate="2015-10-18T10:07:15.813" Score="16" ViewCount="1477" Body="&lt;p&gt;What would be the resulting impact crater of a meteorite hitting bodies of water on Earth?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's take for example the impactor that resulted in &lt;a href=&quot;https://en.wikipedia.org/wiki/Meteor_Crater&quot;&gt;Meteor Crater, Arizona&lt;/a&gt;. What would the impact look like if it hit a shallow sea? A deep ocean? Is there any depth of water which would result in no crater at all?&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="111" LastEditDate="2015-10-19T02:55:26.817" LastActivityDate="2018-10-15T18:54:34.180" Title="Impact craters under water" Tags="|ocean|geomorphology|meteorite|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="6750" PostTypeId="1" AcceptedAnswerId="6821" CreationDate="2015-10-18T13:34:34.673" Score="6" ViewCount="91" Body="&lt;p&gt;What are the main datasets characterizing sea ice typology, thickness, density, &quot;passability&quot;, presence of pressure ridges in the Arctic?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it something that can be detected from the air or a space satellite, or from a surface station only?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How extensive is our coverage of ice conditions in the Arctic?&lt;/p&gt;&#xA;" OwnerUserId="269" LastEditorUserId="4487" LastEditDate="2015-10-28T03:02:25.910" LastActivityDate="2015-10-30T22:44:06.313" Title="Observations of sea ice typology in the Arctic" Tags="|ocean|remote-sensing|sea-ice|arctic|reference-request|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6751" PostTypeId="1" AcceptedAnswerId="6752" CreationDate="2015-10-18T17:55:11.323" Score="6" ViewCount="391" Body="&lt;p&gt;Has anyone ever found or gone looking for similar locations, i.e. volcanic eruption sites in which unfortunate victims – human and non-human –  have been entombed in the volcanic ash, with the possibility of revealing their forms by producing casts from the voids? Such sites, if they exist, could reveal exciting new knowledge about ancient peoples and animals. &lt;/p&gt;&#xA;" OwnerUserId="4658" LastEditorUserId="4658" LastEditDate="2015-10-23T07:51:19.720" LastActivityDate="2015-11-05T10:05:54.657" Title="Are Pompeii and Herculaneum unique?" Tags="|volcanology|paleontology|volcanic-hazard|archaeology|pyroclastic-flows|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6752" PostTypeId="2" ParentId="6751" CreationDate="2015-10-18T20:53:45.453" Score="5" Body="&lt;p&gt;Probably the best known is more recent, the 1902 eruption of &lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Pel%C3%A9e&quot;&gt;Mt. Pelée on Martinique&lt;/a&gt;, where 30,000 people were killed by pyroclastic flows. I don't know the extent of burial - it appears that the city may have been destroyed more by the ash cloud than the dense part of the flow.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2015-10-18T20:53:45.453" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6754" PostTypeId="1" AcceptedAnswerId="6755" CreationDate="2015-10-20T00:53:35.667" Score="6" ViewCount="266" Body="&lt;p&gt;I know that soil is used to filter septic systems within our treatment system, however what happens to this soil that is used in filtration, I know it would be changed every once in a while but what really happens when acidic and basic waste flows through this soil?&lt;/p&gt;&#xA;" OwnerUserId="4662" LastEditorUserId="4487" LastEditDate="2015-10-28T05:21:21.317" LastActivityDate="2015-10-28T05:21:21.317" Title="What would happen if the same soil received waste water contaminants for a long time?" Tags="|water|soil|pollution|groundwater|ecology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6755" PostTypeId="2" ParentId="6754" CreationDate="2015-10-20T02:30:00.757" Score="6" Body="&lt;p&gt;Like many things in Earth Science, the answer is, &quot;It depends.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this case it depends on the composition of the soil and the contaminant you are talking about. Climate, particularly the amount of precipitation, can also have an effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Septic systems are primarily designed to promote aerobic conditions and aerobic bacteria to degrade organic compounds and pathogens. In a well designed and maintained system, that will be effective for a long time. One of the important considerations is to be sure the soil will allow enough infiltration that it doesn't become waterlogged. Some places need a sand mound because the natural soil isn't suitable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some contaminants aren't treated by the septic system. Some are transported down in the infiltrating water with little or no interaction with the soil. These can quite easily contaminate the groundwater if concentrations are too high. Salt,  (NaCl), for example, is transported with practically no &lt;em&gt;retardation&lt;/em&gt;. Many positively charged &lt;em&gt;cations&lt;/em&gt; with charges of 2&lt;sup&gt;+&lt;/sup&gt; or more will be &lt;em&gt;adsorbed&lt;/em&gt; onto the surface of (mainly) clay minerals or in between layers in the clay crystals. They do that because the surface favours them more than the cations that are already present so the new cations replace the old. But the minerals only have a finite ability to exchange the new ions for old. With time the new ions will flow deeper into the unsaturated soils (the &lt;em&gt;vadose zone&lt;/em&gt;) until they breakthrough to the groundwater. How fast this happens depends on the soil properties, the concentration and properties of ions in the waste, and the amount of infiltration.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Negatively charged anions are interesting. They are generally poorly adsorbed by mineral surfaces so they are quite mobile in the subsurface compared to cations. Compounds of oxygen and other elements can form important anions like nitrate (NO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;) and sulfate (SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt;). My favourite is pertechnetate (TcO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;), which makes this man-made radioactive element quite mobile under oxidizing conditions. Since many elements have several valence states, changing the oxidation-reduction conditions can change their mobility.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You mention acidic and basic wastes. These can do several things. First, they can exchange for adsorbed ions on the sediments and compete with others ions, increasing the mobility of the others, Secondly, they can affect the chemical form of the ions in solution. Thirdly, they can react with the minerals and alter them to ones with different properties. Finally, they can affect the microbiology in the sediments and change the ability to degrade contaminants.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is important to inspect and maintain household septic systems by pumping out the tank and checking the leach field for problems. Some places require that you define the location for a replacement leach field before building in case it is needed. Be careful not to put contaminants down your system - especially things like pesticides and herbicides. &lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2015-10-20T02:30:00.757" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6758" PostTypeId="1" AcceptedAnswerId="6764" CreationDate="2015-10-21T14:49:15.390" Score="3" ViewCount="1189" Body="&lt;p&gt;During the day plants photosynthesize and give out oxygen through stomata. But during the night, when half of the planet is dark, half of the earth's trees/plants consumes oxygen to survive. At that time when an entire hemisphere is producing only $\ce{CO_2}$ and there is no source of $\ce{O_2}$, why don't half of the life forms die? And 12 hours later, the other half when they are in darkness?&lt;/p&gt;&#xA;" OwnerUserId="4668" LastEditorUserId="28050" LastEditDate="2015-10-29T15:52:24.293" LastActivityDate="2015-10-29T15:52:24.293" Title="Why don't all living beings die at night due to lack of oxygen?" Tags="|atmosphere|co2|biogeochemistry|seasons|diurnal-cycle|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6759" PostTypeId="1" CreationDate="2015-10-21T21:15:50.053" Score="9" ViewCount="312" Body="&lt;p&gt;&lt;strong&gt;Paper:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://geodesy.unr.edu/publications/DonnellanEtAl2015.pdf&quot;&gt;Potential for a large earthquake near Los Angeles inferred from the 2014 La Habra earthquake&lt;/a&gt; (2015)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously there has been much discussion on  the viability of earthquake prediction. This recent paper presents some rather bold claims:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The calculated probability for a M ≥ 6 earthquake within a circle of&#xA;  radius 100 km, and over the 3 years following 1 April 2015, is 35%.&#xA;  For a M ≥ 5 earthquake within a circle of radius 100 km, and over the&#xA;  3 years following 1 April 2015, the probability is &lt;strong&gt;99.9%&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;On the other hand, the USGS is saying those figures are too high:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The USGS conducts its own look at quake risk in California — the most&#xA;  recent version is called Uniform California Earthquake Rupture&#xA;  Forecast, Version 3. Jones said that, according to those models, there is only an 85&#xA;  percent chance of a magnitude 5 or 6 quake in the same region over a&#xA;  three-year period. &quot;It's nowhere near a 99.9 percent number,&quot; Jones said.&#xA;  USGS released a statement on its Facebook page saying that the lack of&#xA;  details on how this number was reached &quot;makes a critical assessment of&#xA;  this approach very difficult.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The LA Times has it reported here: &lt;a href=&quot;http://touch.latimes.com/#section/-1/article/p2p-84786019/&quot;&gt;http://touch.latimes.com/#section/-1/article/p2p-84786019/&lt;/a&gt; , which says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The study’s lead author, Jet Propulsion Laboratory principal research scientist Andrea Donnellan, said in an interview that the 99.9% figure was not a central conclusion of the paper and should not be viewed as an official forecast.&#xA;  “As scientists, we were not putting out an official forecast. We were putting out something in a paper to test,” Donnellan said.&#xA;  Donnellan said she considers the 99.9% number a test of a model, or algorithm, on the probability of future earthquakes. &#xA;  “We never said in this paper we were predicting an earthquake. And we said that's the probability of an event,&quot; Donnellan said. &quot;There is still a 0.1% chance it won't happen. So we need to test it. And that's what we are doing as scientists.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Has anyone verified this study? Is there anything wrong with it? How were they able to arrive at such a high probability?&lt;/p&gt;&#xA;" OwnerUserId="3087" LastEditorUserId="543" LastEditDate="2015-10-22T19:24:53.643" LastActivityDate="2016-04-11T07:57:25.233" Title="Can a 99.9% probability of an M≥ 5 earthquake within a 3-year period be verified?" Tags="|geology|seismology|earthquakes|predictability|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6760" PostTypeId="1" AcceptedAnswerId="6761" CreationDate="2015-10-22T00:20:52.263" Score="17" ViewCount="4861" Body="&lt;p&gt;I'm new to this site and certainly not someone with any real background in atmospheric science, so please forgive me if this question is a little stupid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I recall learning in High School about mountain ranges frequently being dry on one side and lush on the other. The explanation was that as a cloud approaches the mountain from the lush side, it releases any rain so it can rise over the range. This always seemed like a silly explanation to me, because in the way it's phrased, it seems to imply that the cloud is cognizant. Also, this would mean that clouds can only (for the most part) approach the mountain from the lush side, which may or may not be true, but I don't know why. So I'm sure there's a better explanation as to why this happens, but I'm hoping someone can explain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="4674" LastEditorUserId="4487" LastEditDate="2015-10-25T05:46:27.553" LastActivityDate="2023-04-11T13:48:28.147" Title="Why One Side of Mountain Range is Lush" Tags="|meteorology|clouds|precipitation|mountains|geobiology|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6761" PostTypeId="2" ParentId="6760" CreationDate="2015-10-22T00:52:32.160" Score="27" Body="&lt;p&gt;The Cascade Mountain Range in the US Pacific Northwest is a good example to use to explain this. The predominant wind direction is from the West - over the Pacific Ocean. The air over the ocean picks up moisture from evaporation. After it passes the coast, the mountains cause the air to rise. As it does so it cools. Colder air can hold less water vapour than warm air so that the air becomes saturated with water and it condenses out into clouds. With enough condensation you get rain - a lot of it on the western side of the mountains. So you had it backwards, the rain doesn't allow the air to rise - the rising allows it to rain. Clouds mainly approach from the lush side because that is the prevailing wind direction but it is better say that it is the lush side because clouds mainly approach that way. When wind comes from the other direction is travelling across land so it contains less water and the cooling generally isn't enough to cause rain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once the air crosses to the other side of the mountain range it warms and becomes undersaturated with water. Clouds often disappear and even if they remain you aren't getting further condensation to produce a lot of rain. So those areas are much drier.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8Dp4y.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8Dp4y.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1242" LastEditorUserId="543" LastEditDate="2015-10-22T04:59:21.547" LastActivityDate="2015-10-22T04:59:21.547" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6762" PostTypeId="2" ParentId="6760" CreationDate="2015-10-22T02:01:28.673" Score="9" Body="&lt;p&gt;I'll augment the other answer with an example.  Consider a theoretical north-south oriented mountain range that rises 2000 m above sea level and the land on either side of the range is at sea level. A little ways west of the mountain is ocean.  The location is the mid-latitudes and the prevailing wind is from the west.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Air along the surface travels above water, picking up moisture.  Lets assume a surface temperature of 28 °C and a dewpoint of 23 °C once the air reaches the base of the mountain on the west side.  This parcel now rises the 2000 m vertical height of the mountain.  At around 500 m the parcel has cooled to saturation and now has a temperature of 22 °C and a dew point of 22 °C.  This height will also be the altitude where clouds form.  At and above 500 m the mountain will be cloudy.  The parcel will continue to rise another 1500 m to the top of the mountain at 2000 m where its temperature has now cooled to about 16.5 °C.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the temperature dropped from 22 °C to 16.5 °C water condensed to contribute to cloud water and rain.  In total, for every kg of air flowing up the mountain in this state, 3 g of liquid water is produced via condensation.  This windward side of the mountain with the moist upslope flow is going to be lush from frequent and abundant rain showers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once the parcel tops the mountain and begins to flow down the lee slope it will begin to warm and relative humidity will drop. Any cloud blown over the mountain top will evaporate as it moves downslope. By the time the parcel reaches the ground at sea level east of the mountain it has a temperature of 36 C and a dewpoint of 19.5 °C - hot and dry.  The less slope and the region to the east will be arid.  Regions like this are referred to as being in the &quot;rain shadow&quot; of a mountain.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These numbers are ballpark back-of-the-envelope estimates from a Skew-T diagram and while not exact they are representative.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="725" LastEditDate="2017-03-25T12:21:11.327" LastActivityDate="2017-03-25T12:21:11.327" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6764" PostTypeId="2" ParentId="6758" CreationDate="2015-10-22T17:22:44.370" Score="5" Body="&lt;p&gt;The rates at which plants consume CO$_2$ and animals consume O$_2$ is minuscule compared to the vast amounts of CO$_2$ and O$_2$ in the atmosphere. The amount of change overnight is not even measurable, unless the plants are in an enclosed structure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Interestingly, there is a variation in CO$_2$ concentraion over the course of a year as the Northern Hemisphere (where most of the land vegetation is) goes through its seasons. &lt;a href=&quot;http://www.esrl.noaa.gov/gmd/ccgg/trends/co2_data_mlo.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here is a plot of CO$_2$ over several decades.&lt;/a&gt; It shows an annual cycle superimposed on the general upward trend from the accumulation of man-made CO$_2$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CEgsC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CEgsC.png&quot; alt=&quot;Full Mauna Loa CO2 record&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The red trace is the actual data, and the black trace is the time averaged fit to the data.&lt;/p&gt;&#xA;" OwnerUserId="4487" LastEditorUserId="28050" LastEditDate="2015-10-29T15:48:10.077" LastActivityDate="2015-10-29T15:48:10.077" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6765" PostTypeId="2" ParentId="6746" CreationDate="2015-10-22T19:38:39.977" Score="3" Body="&lt;p&gt;Homogeneous simply means “the same”. In the paper you have read about AOT (Aerosol Optical Thickness, I'm assuming?), the software used to process the data requires the user to select a grid cell size – at a sufficiently small size, the properties of the atmosphere can be assumed to be the same everywhere inside the cell, i.e. homogeneous, to allow the software to perform its calculations. There's little point in selecting a grid cell size smaller than the distance scales that are interesting and/or meaningful, or smaller than the scale on which anyone could/would measure the properties of the atmosphere you are interested in.  As an extreme example, there would be little point in finding/calculating the Aerosol Optical Thickness for every square centimetre across a geographical region!&lt;/p&gt;&#xA;" OwnerUserId="4658" LastActivityDate="2015-10-22T19:38:39.977" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6766" PostTypeId="1" CreationDate="2015-10-23T14:53:17.337" Score="6" ViewCount="1254" Body="&lt;p&gt;I have seen the term MBf used in a couple of places (&lt;a href=&quot;http://www.portofbaja.hu/index.php?lang=en&amp;amp;page=services&quot;&gt;a ramp specification&lt;/a&gt; and &lt;a href=&quot;https://www.yumpu.com/en/document/view/13316686/feasibility-study-the-rehabilitation-of-the-szigetkoz-reach-of-the-/151&quot;&gt;a Hydrological Study&lt;/a&gt;) to describe height or depth of water. What is this unit? Can it be converted to meters?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For bonus points: how tall is the ramp at Baja?&lt;/p&gt;&#xA;" OwnerUserId="4687" LastEditorUserId="111" LastEditDate="2015-10-23T17:09:24.987" LastActivityDate="2015-10-24T05:24:41.850" Title="Water levels: What does &quot;mBf&quot; mean?" Tags="|sea-level|terminology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6767" PostTypeId="2" ParentId="6766" CreationDate="2015-10-23T15:28:01.470" Score="12" Body="&lt;p&gt;It is &quot;mean sea level above the Baltic Sea&quot;, in meters (&lt;a href=&quot;http://aerapa.conference.ubbcluj.ro/2010/pdf/ZNagy.pdf&quot;&gt;source&lt;/a&gt; on page 109). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That explains why it is used mainly in East-European countries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.baltex-research.eu/publications/Books%20and%20articles/The%20Changing%20Level%20of%20the%20Baltic%20Sea.pdf&quot;&gt;Martin Ekman - The Changing Level of the Baltic Sea during 300 Years - A clue to understanding the Earth&lt;/a&gt; shortly mentions some historical 'zero points' (page 111). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As mentioned in the comments: &#xA;mBf means &lt;em&gt;méter Balti felett&lt;/em&gt; (Hungarian for meters above Baltic Sea). They also use meters above the Adriatic as a datum (&lt;a href=&quot;https://en.wikipedia.org/wiki/Metres_above_the_Adriatic&quot;&gt;https://en.wikipedia.org/wiki/Metres_above_the_Adriatic&lt;/a&gt;, mAf from &lt;em&gt;méter Adria felett&lt;/em&gt;).&lt;/p&gt;&#xA;" OwnerUserId="595" LastEditorUserId="595" LastEditDate="2015-10-23T17:16:11.770" LastActivityDate="2015-10-23T17:16:11.770" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6772" PostTypeId="2" ParentId="5453" CreationDate="2015-10-24T00:56:13.527" Score="3" Body="&lt;p&gt;Apart from today, yes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Back in the Cambrian (~500 million years ago), there was a continent in the southern hemisphere called Gondwana. It was a combination of several modern day continents: South America, Australia, Antarctica and Africa. A small piece of North America that corresponds mostly to modern day northern Canada existed in the northern hemisphere, called Laurentia. Curiously, some parts of northwestern Europe were part of that as well (Scotland, Norway).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Between the Devonian (~370 million years ago) and the Triassic (~200 million years ago) almost every continent on the Earth was amalgamated into one super continent called Pangaea, including Gondwana and Laurentia. During the Jurassic and Cretaceous (~150 million years ago) the entire thing separated due to the opening of the Atlantic Ocean, sending North America north west and South America south west. Since then the two continents were separated, until very recently (geologically speaking) that a land bridge formed between the two.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A very good website with reconstructions of paleogeographical maps is this one:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://scotese.com/&quot; rel=&quot;nofollow&quot;&gt;http://scotese.com/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that these are all interpretations and they are open for debate. But the general idea is correct.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-10-24T00:56:13.527" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6773" PostTypeId="2" ParentId="4569" CreationDate="2015-10-24T01:01:46.627" Score="4" Body="&lt;p&gt;Here's an idea:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can use dark chocolate and white chocolate. Use a grater to create &quot;sediments&quot;: layers of alternating grated dark and white chocolate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now heat them up just before melting so you can stick them together with pressure, preserving the layered structure. Now fold them. There's your &quot;metamorphic&quot; rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then, just melt the entire thing to create some chocolate-lava flows. Grate them again and eat!&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-10-24T01:01:46.627" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6774" PostTypeId="1" CreationDate="2015-10-24T02:18:50.497" Score="3" ViewCount="1436" Body="&lt;p&gt;Does it come from&#xA;a)atmospheric lightning and ozone dissociation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;b)meteorite impacts early in the earth's geological history.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;c)Paleozoic volcanic activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;d)photosynthetic processes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;e)photodissociation of water molecules (from solar ultraviolet light).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I believe it is D, but not 100%.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="4689" LastEditorUserId="4487" LastEditDate="2015-10-25T00:28:32.700" LastActivityDate="2015-10-28T22:46:37.427" Title="The free oxygen (O$_2$) in the atmosphere is largely a result of what process?" Tags="|homework|earth-system|biogeochemistry|geobiology|atmospheric-chemistry|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6775" PostTypeId="2" ParentId="6774" CreationDate="2015-10-24T03:20:32.367" Score="7" Body="&lt;p&gt;You are correct in thinking that oxygen comes from photosynthesis. In fact it is so much associated with photosynthesis, as opposed to any inorganic process, that the presence of oxygen in the atmospheric spectrum of other planets (solar or exoplanets) is reckoned to be one of the best indicators of life beyond Earth - not that such oxygen has been discovered yet. &#xA;Ozone is made from pre-existing oxygen but with an atmospheric half life of only about 12 minutes, it spontaneously turns back into oxygen again very rapidly, and is highly sensitive to ozone-disrupting agents such as CFCs. &#xA;Meteorites have little, if any free oxygen. Indeed, many meteorites contain Ni-Fe which would rapidly mop up any free oxygen if it were originally present. Volcanic activity reflects the fugitive gasses of a magma chamber, which contains F, Cl, CO2, CO, H2O, H2S, N2, inert gasses, and hydrogen. Oxygen can occur in in a few volcanic emanations but this is rare and of small scale. On balance, volcanoes are oxygen absorbers rather than emitters. Photo-dissociation occurs to some extent high in our atmosphere in response to both solar and cosmic radiation. The result is H2O = H+ +OH- so there is no free oxygen involved. In any case, the two ions recombine fairly rapidly. Photo-dissociation is important in dense interstellar gas clouds far out in space where they may be subject to intense UV-radiation. Even here, the tendency is to mop up rather than release free oxygen.&#xA;The photosynthetic activity and mechanism on Earth has changed dramatically. It is the only known mechanism which can and does release large quantities of free oxygen. This started more than 3 billion years ago, but didn't raise the atmospheric oxygen level significantly prior to about 2.5 billion years ago. Evolution of the Earth's oxygen has been a long and complex affair, with high levels of oxygen only starting to emerge in the Eocambrian. The Earth's first oxygen would have been a noxious, toxic, and horribly reactive gas from the perspective of the Earth's earliest unicellular organisms. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;New information just in: Nature magazine, 28th October 2015, has reported an astonishingly high oxygen concentration, of 3.8%, from the gaseous emissions from comet 67P, as measured by the Rosetta space probe. This has taken everyone by surprise (including myself) and may require a re-think about comet formation.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2015-10-28T22:46:37.427" LastActivityDate="2015-10-28T22:46:37.427" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6776" PostTypeId="2" ParentId="4664" CreationDate="2015-10-24T03:23:39.513" Score="2" Body="&lt;p&gt;Mostly stratocumulus with a scattering of emergent cumulus towers which have been lofted by strong internal convection cells.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-24T03:23:39.513" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6777" PostTypeId="2" ParentId="5313" CreationDate="2015-10-24T03:34:43.753" Score="5" Body="&lt;p&gt;The true reflected colour of a cloud doesn't change from white unless there is serious pollution, such as Saharan dust, wildfire soot or industrial emissions. None of these produce a blue colour, so the question really becomes 'what reflected light looks blue', and that is a function of the direction of view (towards or away from the sun), the subject's perception of colour (which can be surprisingly deceptive), and how much atmospheric blue back-scatter the cloud is reflecting. The latter accounts for most of the 'blue cloud' that we see.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-24T03:34:43.753" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6778" PostTypeId="2" ParentId="4569" CreationDate="2015-10-24T04:01:48.147" Score="-1" Body="&lt;p&gt;If you want to stick to actual geological products rather that kitchen substitutes, you could demonstrate the properties of an extraordinary natural evaporite mineral, Mirabilite, Na2.SO4.10H2O. This is found in some of the East African salt lakes, amongst other places. Under dry conditions it dehydrates to a white powdery mineral, Thenardite. Under warm conditions it dissolves in its own water of crystallization.  In some East African lakes, Mirabilite saturated water splashes on the beach by wave action, where it dries out as crystals. Then when it warms in the sun, it turns back to a liquid and drains back into the Lake. It's a phase change rather than a chemical change, but it gets across the message of cyclicity. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-24T04:01:48.147" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6779" PostTypeId="2" ParentId="5453" CreationDate="2015-10-24T04:10:45.700" Score="2" Body="&lt;p&gt;Further to Michael's answer, the evidence for both America's once belonging to a supercontinent, prior to opening of the Atlantic, is abundant. Some examples;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Trilobites from the Cambrian of NW Scotland belong more to the North&#xA;American type than to the European-Asian (Tethyan) type. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Get a geological map of Brazil and Africa, and see how well they fit&#xA;together.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;There are fluvially deposited diamonds found in South America but no&#xA;source area, i.e. no kimberlites. This didn't make sense until it&#xA;was realized that the diamonds were transported in westward flowing&#xA;rivers from kimberlites in Africa prior to the rift which separated&#xA;South America from Africa.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="725" LastEditDate="2017-03-25T12:36:11.333" LastActivityDate="2017-03-25T12:36:11.333" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6780" PostTypeId="2" ParentId="6766" CreationDate="2015-10-24T05:24:41.850" Score="4" Body="&lt;p&gt;mBf refers to the Baltic sea level, which differs from sea level elsewhere in the world for two reasons. Firstly, the Baltic is less saline, and hence less dense, than the North Sea and Atlantic, to which it is connected. Consequently, since it is in quasi-hydrostatic equilibrium with the North Sea, it is also higher than the North Sea. Secondly, in response to the retreat of the Scandinavian ice cap, the land around the Baltic has risen by up to 9 metres per century. The current rate of change being 0.3 to 12.3 mm per year. Put another way, the &lt;em&gt;apparent&lt;/em&gt; sea-level has fallen by anything up to 9 metres a century. The mBf is therefore used as the local sea level reference datum for such activities as estuary embankment works, mine drainage, and industrial cooling water intakes. See, for example:&#xA;&lt;a href=&quot;http://www.baltex-research.eu/publications/Books%20and%20articles/The%20Changing%20Level%20of%20the%20Baltic%20Sea.pdf&quot; rel=&quot;nofollow&quot;&gt;http://www.baltex-research.eu/publications/Books%20and%20articles/The%20Changing%20Level%20of%20the%20Baltic%20Sea.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-24T05:24:41.850" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6781" PostTypeId="2" ParentId="2994" CreationDate="2015-10-24T09:23:34.927" Score="0" Body="&lt;p&gt;Question; How are 'Morning Glory' clouds &lt;strong&gt;maintained&lt;/strong&gt;?&#xA;What meteorological factors &lt;strong&gt;maintain&lt;/strong&gt; the Morning Glory roll-clouds?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Part of Answer one; However, devoid of other atmospheric forcing these waves can travel thousands of KMs without loosing much energy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-Shows that the original question is not really answered. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to rip this question apart;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Why Morning?&lt;/li&gt;&#xA;&lt;li&gt;Why (mostly) only August-October?&lt;/li&gt;&#xA;&lt;li&gt;Why roll-cloud?&lt;/li&gt;&#xA;&lt;li&gt;Why are they so wide and an last so long.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;And my answer; &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;They occure at Morning because that's the point where the cold night air hit's the warm day air. This night air is fixed to the Earths rotation, an at August October the &lt;a href=&quot;https://physics.stackexchange.com/questions/214042/earths-kinetic-energy-change&quot;&gt;Earth's rotation speed is decelerating&lt;/a&gt;. Normally the Sun causes the winds through heating and evaporation. But Morning Glory clouds are clouds caused be the Earth.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;They mostly occur on August-Ocotber, because the Land/Sea balance of the Earth causes the Earth rotation speed to be dependable on Solar equator. And as these are practically constant; Highest land mass amount on northern hemispehre, and generally less on southern hemispehre, this concludes that the most of these, must occure at this time frame, as during that time the earths rotation speed typically decelertes. But as single years might be really different, they can occure any time of the year. But it would be almost a miracle to see them at late April - Early July. Pls. look the link above and the picture there.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;They are roll clouds, as the velocity change causes &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydraulic_jump&quot; rel=&quot;nofollow noreferrer&quot;&gt;a hydraulic jump&lt;/a&gt;. &#xA;Such an Jump is really efficient energy dissipator. A steady jump normally dissipates 45% of the energy. But the Morning glory clouds can be also understood as an oscillating waves, means that the dissipation can be only 5-15%. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;So though they are so effective energy dissipators, they can last long because compared to the Earths kinetic energy their energy amount is almost nothing. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="3098" LastEditorUserId="-1" LastEditDate="2017-04-13T12:40:15.470" LastActivityDate="2015-10-24T09:23:34.927" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6782" PostTypeId="1" CreationDate="2015-10-24T12:32:27.063" Score="5" ViewCount="65" Body="&lt;p&gt;I would like to begin studying the geology of the Andes, with particular respect to the tectonics and paleogeography of the region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have been searching on-line resources for some time and I would like to start reading a book on the topic, but I am not finding any titles focussing on the geology, tectonics and paleogeography of the area. Would anybody have any suggestion, if possible in Spanish?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since I have found the reference-request tag, I hope this question is not off topic here and, if it is, I will delete it. I thank you for any answer!&lt;/p&gt;&#xA;" OwnerUserId="620" LastEditorUserId="4487" LastEditDate="2015-10-25T05:46:52.183" LastActivityDate="2015-10-31T15:47:57.370" Title="Resources on Andean geology" Tags="|geology|mountains|tectonics|paleogeography|reference-request|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6783" PostTypeId="1" AcceptedAnswerId="6789" CreationDate="2015-10-25T15:02:34.907" Score="9" ViewCount="273" Body="&lt;p&gt;Are there any examples of now completely landlocked former river mouths or estuaries that became so after continental collision? As an example, consider the closure of the ocean between India and the Eurasian Plate – is there any evidence today, e.g. up in the Himalayas, of ancient river mouths or estuaries that are now stranded on the convergent boundary of the two continents?&#xA;As a corollary are there any rivers today which contain evidence of an opposite flow direction in the past, as a consequence of the above? Such cases, if they exist, would be interesting mirrors to the idea of continental rifting's contribution to river flow reversal (I'm thinking of the extraordinary discovery of the River Amazon's former east-to-west flow before South America rifted away from Africa: &lt;a href=&quot;http://www.livescience.com/4253-amazon-river-flowed-ancient-times.html&quot; rel=&quot;nofollow&quot;&gt;http://www.livescience.com/4253-amazon-river-flowed-ancient-times.html&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reference:&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Continental_collision&quot; rel=&quot;nofollow&quot;&gt;Continental collision&lt;/a&gt;&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Continental_drift&quot; rel=&quot;nofollow&quot;&gt;Continental drift&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4658" LastEditorUserId="4658" LastEditDate="2015-10-26T07:40:08.283" LastActivityDate="2015-10-26T10:47:37.013" Title="Continental collision – evidence left of river mouths and estuaries along the boundary?" Tags="|plate-tectonics|rivers|paleogeography|coastal|mountain-building|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6784" PostTypeId="1" CreationDate="2015-10-25T16:55:23.913" Score="4" ViewCount="422" Body="&lt;p&gt;I googled &quot;the flood and freshwater fish&quot; and came up with this question &lt;a href=&quot;https://christianity.stackexchange.com/&quot;&gt;Christianity StackExchange&lt;/a&gt;: &lt;a href=&quot;https://christianity.stackexchange.com/questions/5958/how-did-noah-preserve-fresh-water-fish&quot;&gt;How did Noah preserve fresh water fish?&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The writer makes a lot of claims like how the salinity of the oceans was lower in 2500BC  (time of the flood), how an experiment found that saltwater fish and freshwater fish can live in the same environment (he didn't provide a reference) etc...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My questions are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;What was the ocean salinity around 2500 BC, and could freshwater fish tolerate that level of salinity?&lt;/li&gt;&#xA;&lt;li&gt;If the ocean was much less saline, is it possible to have increased to present day levels in 4500 years?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="4696" LastEditorUserId="-1" LastEditDate="2017-04-13T12:56:54.477" LastActivityDate="2015-10-27T10:31:59.687" Title="Is this scientific explanation of The Bible flood accurate?" Tags="|ocean|earth-history|paleoclimatology|evolution|flooding|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6786" PostTypeId="2" ParentId="6784" CreationDate="2015-10-25T20:25:36.527" Score="12" Body="&lt;p&gt;Fishing through the links mentioned over at Christianity SE, I netted this scientific paper about freshwater and marine fish: &lt;a href=&quot;http://www.wienslab.com/Publications_files/Vega_Wiens_PRSL_2012.pdf&quot;&gt;Why are there so few fish in the sea?&lt;/a&gt;. Apparently the bulk (96%) of marine species have a single &lt;strong&gt;&lt;em&gt;freshwater&lt;/em&gt;&lt;/strong&gt; ancestor species extant 300 Mya (300 million years ago). Descendants of this species did not enter the ocean until about 180 Mya, with the greatest diversification and subsequent dominance of the oceans starting 110 Mya. Another fact: only 4% of current fish species can thrive in both saltwater and freshwater (&lt;em&gt;e.g., salmon, trout, ...&lt;/em&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get anywhere near a hypothetical event equivalent to Noah's flood would require accepting dozens of &lt;em&gt;counterfactual&lt;/em&gt; assumptions, and a total misunderstanding of geology, evolution, paleontology, not to mention conservation of mass (&lt;em&gt;where did all the water come from?&lt;/em&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But to address the narrow issue of survival of fish, one could imagine that the flood happened so rapidly as to create a very thick layer of freshwater on top of the saltwater. Freshwater is considerably lighter than saltwater, and would &quot;float&quot; on the saltwater. Marine mammals would be okay in freshwater for a few days. Then the waters could recede (&lt;em&gt;where did all the water go to?&lt;/em&gt;), and maybe enough freshwater species would end up in the new freshwater lakes and streams.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as the Ocean being less salty, there is no evidence for that. A lower salinity is postulated to fit into the theories of the Young Earth proponents. Paleosalinity is a complex study. You can browse through these references &lt;a href=&quot;http://www.personal.soton.ac.uk/ejr/Rohling-papers/2000-Rohling%202000%20Paleosalinity%20confidence%20limits%20Mar%20Geol%202000.pdf&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/1999PA900008/pdf&quot;&gt;here&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A flood such as this would have enormous, I would say overwhelming, geological, geographical, and paleontological evidence left behind, which in fact does not exist. But everything is possible with miracles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You may be interested in this paper: &lt;a href=&quot;http://www.researchgate.net/publication/222471228_An_Abrupt_Drowning_of_the_Black_Sea_Shelf&quot;&gt;An Abrupt Drowning of the Black Sea Shelf&lt;/a&gt; which led to this book &lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/0684859203&quot;&gt;NOAH'S FLOOD: The New Scientific Discoveries About the Event That Changed History&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4487" LastEditorUserId="4487" LastEditDate="2015-10-25T20:41:14.390" LastActivityDate="2015-10-25T20:41:14.390" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6787" PostTypeId="2" ParentId="6749" CreationDate="2015-10-25T20:40:25.793" Score="4" Body="&lt;p&gt;You don't need much of a depth to be able to stop a meteorite. Less than 100 m water depth should be enough to stop such a meteorite as shown in the provided link without any particular crater on the sea bed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://physics.stackexchange.com/questions/137671/meteorite-like-impact-of-a-drop-of-yogurt/&quot;&gt;The Physics part of the story is provided here;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rest is mathematics. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Short. At collision all the kinetic energy is transferred to Pressure, and thereafter this pressure is again transferred to kinetic energy; it is explosion. Very simply said it's &lt;a href=&quot;https://en.wikipedia.org/wiki/Bernoulli%27s_principle&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bernoulli principle.&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;By this reason it doesn't penetrate practically any deeper in water than in Earth, and as the water then smooths up you have no crater. A very simple scaling might be made with density; typical rock / water; 2.3/1 depth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you need some visual proof, try this video; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=cp5gdUHFGIQ&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=cp5gdUHFGIQ&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3098" LastEditorDisplayName="user1161" LastEditDate="2017-06-12T22:51:38.560" LastActivityDate="2017-06-12T22:51:38.560" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="6788" PostTypeId="1" CreationDate="2015-10-26T05:19:30.060" Score="9" ViewCount="3621" Body="&lt;p&gt;Recently I started being more interested in the rational details of the sciences (... being often challenged about them by a creationist friend) and one of the creationist 'theories' I've encountered is how the law of superposition - i.e. the claim that layers of rocks form with the top layer being younger than the bottom - can be falsified. They mentioned some creationist experiments where layers formed 'sideways' and used it as one of the arguments to 'prove' that Earth does not have to be millions of years old.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now I do not want to engage in a theological discussion, but I was wondering how accurate law of superposition is. Most articles I've read refer to it as an axiom of geology - i.e. something that is assumed, rather than proved. At the same time I am aware of the fact that it's a &quot;first level big picture axiom&quot;, in that everyone is aware of the fact that under special circumstances the details get a bit foggy, but looking at the whole world it is correct &quot;often enough&quot; to warrant making it an axiom to simplify the theory for beginning geologists.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus my question is: In the global scope, how significant are the deviations from law of superposition in the structure of Earth's strata? Would you say less than 1% of the world show any significant deviation from the law?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I apologise for any jargon misunderstandings I may have committed.&lt;/p&gt;&#xA;" OwnerUserId="4699" LastActivityDate="2023-09-25T13:22:33.090" Title="How accurate is the law of superposition?" Tags="|geology|stratigraphy|geologic-layers|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6789" PostTypeId="2" ParentId="6783" CreationDate="2015-10-26T09:08:12.943" Score="2" Body="&lt;p&gt;There were certainly river mouths or estuaries in the rivers that drained off the proto-Himalayas into the last retreating stages of the Neo-Tethys Ocean. Such rivers comprised dozens of small rivers and the westward-flowing Proto-Ganges itself, which deposited the Siwalik formation which now forms the Lesser Himalayas. That is, the southernmost 'soft' 'salt and pepper' sandstones, up to about 2500 metres , which now abut the Indian plain. However, there is almost nothing left in terms of recognizable estuarine sedimentary structures. It has all been compressed, folded, imbricated, overthrust and subject to varying degrees of diagenesis and cataclasis. Most of this sediment was meandering mud flats, sandy outwash and restricted shallow marine sediments, with some similarities to the 'cuvette' environments of the European Old Red Sandstone. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to the second question, your mention of the closure of the Tethyan Ocean  leading to the Indian-Tibetan collision suggests that you already suspect (correctly) that the Ganges is a case in point. It's headwaters were  originally in southwestern China, and it originally flowed westwards along the foot of the proto-Himalayas (what is now the high Himalayas)and out to the Indian Ocean somewhere in the vicinity of what is now the Indus basin in Pakistan. As continental collision progressed there was continental up-warping in what is now  the Himachal Pradesh area of India. This reversed the Ganges drainage so that it now flows eastwards. &#xA;This has important modern implications, as it was the originally westward-flowing Ganges that brought arsenic from the marine Tethyan sediments of western China, and which is now the source of the arsenic groundwater problem over much of Bangladesh and adjacent areas. &#xA;See also my paper: &lt;a href=&quot;http://link.springer.com/article/10.1007%2Fs10653-005-7102-9&quot; rel=&quot;nofollow&quot;&gt;http://link.springer.com/article/10.1007%2Fs10653-005-7102-9&lt;/a&gt;   But don't pay the exorbitant price! - I can send you the original text for free! :-)&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="111" LastEditDate="2015-10-26T10:47:37.013" LastActivityDate="2015-10-26T10:47:37.013" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6790" PostTypeId="2" ParentId="6788" CreationDate="2015-10-26T17:05:56.230" Score="10" Body="&lt;p&gt;The principle does not apply to all materials on earth as observed by us but is primarily concerned with sediments and rocks that form from sediments. Since sedimentation is a process driven by gravity grains settle one on top of others and there is no possibility to change that without adding additional processes. So from this perspective the principle is 100% in situations where it is applicable. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is of course not uncommon to find situations where older material overlays younger. In such cases there has been additional forces (natural mind you) in action. It is for example possible for intrusions (magma) to be injected in older solid rocks thus completely changing the age sequence. It is also possible for crustal movement (tectonics) to fold the bedrock and thrust parts of the bedrock to overlay other parts hence creating situations where younger rocks seem to undelie older. It is also possible for sediments to slide or move downslope so that a reverse or at least disturbed age sequence is established. I could continue &lt;em&gt;ad infinitum&lt;/em&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So many possibilities exist to obtain such cases but always with a logical explanation involving post-sedimentary processes. To correctly interprete observations, one has to have gained full understanding of the geological setting and history as well as physical processes. It is not generally wise to look at an outcrop or cut and create a larger scale interpretation without such background knowledge.&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2015-10-26T17:05:56.230" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6791" PostTypeId="1" AcceptedAnswerId="6792" CreationDate="2015-10-27T02:39:51.803" Score="4" ViewCount="505" Body="&lt;p&gt;To what extent has the Earth's surface been geologically mapped?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For instance, what fraction has been surveyed at 1:10 000, 1:100 000 or 1:1 000 000 scale?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: By 'surface' I mean land surface, not covered by water.&#xA;By 'geologically mapped' I mean 'described by a conventional geological map which shows the exposed surface lithologies and their structures'.&lt;/p&gt;&#xA;" OwnerUserId="4705" LastEditorUserId="4705" LastEditDate="2015-10-28T12:58:53.453" LastActivityDate="2015-10-28T12:58:53.453" Title="To what extent has the Earth's surface been geologically mapped?" Tags="|geology|regional-geology|cartography|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6792" PostTypeId="2" ParentId="6791" CreationDate="2015-10-27T05:20:21.673" Score="3" Body="&lt;p&gt;As far as I know there are no official data on this. All I can do is give a rough estimate, based upon work and personal interest in about 30 countries, over 40 years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can say with certainty that everywhere has been mapped at the 1: million scale although, at this 'reconnaissance scale', at least half of the land surface is only sketchily known, with sparse ground-truth in areas covered by ice, dense forest or drifting sand. In such areas the best detail is probably from geophysics rather than from actual surface mapping.&lt;br /&gt;&#xA;For example, gravity anomaly by satellite, or aeromagnetics. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At 1:100,000 scale most areas (I'm guessing 80 to 90%) are mapped wherever there is reasonable bedrock exposure. Certainly in Europe, the America's and most of the world's mountain chains you would be hard-pressed to find areas that haven't been mapped at this scale, although the maps are not all available ('commercial, in-confidence', etc.).&lt;br /&gt;&#xA;The only exception I can think of is parts of the less accessible Himalayas, where the scales of around 1/2 million seem to be the best on offer.&lt;br /&gt; That's not to say that there isn't much scope for further mapping at 1:100,000 scale. Rock exposure changes over time, and many of the existing maps could use a more detailed upgrade, especially in respect of microfossil zonation, facies zonation and structural analysis. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;1:10,000 scale or even finer detail is only for the 'very interesting' bits, such as ore deposits, mining tenements, reservoirs and engineering site investigations. There are thousands, if not millions of such maps, most of which are not publicly available. Your guess is as good as mine about what percentage of land is covered by such maps, but I would guess &amp;lt;&amp;lt;1%.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;hr&gt;&#xA;PS I forgot to add that most geology students and academics undertake geological mapping for thesis or teaching purposes. Again, they are often not published, and one has to search quite hard for a copy. These scales are usually somewhere between 1:10,000 and 1:100,000&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="595" LastEditDate="2015-10-27T19:50:14.153" LastActivityDate="2015-10-27T19:50:14.153" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6793" PostTypeId="2" ParentId="6784" CreationDate="2015-10-27T05:52:07.777" Score="4" Body="&lt;p&gt;The geological, hydrological, meteorological, palaeontological, evolutionary  and hydrodynamic absurdities of the literal reading of Noah's Flood could fill at least one lengthy book, in fact many such books, and are way too numerous to do justice in a short Stack Exchange article. The short answer is NO, one cannot even begin to explain the discrepancies between science and Biblical literalism, such as the origin of freshwater and saltwater fish, without incurring cognitive dissonance upon a massive scale. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;However&lt;/em&gt;, please consider that the true answer lies not in 'scientific explanation' but in theology - which is not strictly an Earth Sciences matter. Noah's flood is part of the Bible's introduction, written in the Semitic literary idiom of about 3500 years ago, which was strong on allegory, poetic imagery and parable; i.e. a spiritual story within a story. Noah's flood may, or may not, have its roots in prehistoric memory, such as the flooding of the Black Sea, but reading it as if it were a modern text, written in Greco-Roman proto-scientific literalism, is perverse, and is not taking the Bible seriously. Genesis 1-11 is a superb allegory of the entire sweep of human spiritual history - so please don't get hung up about nonsensical scientific explanations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, just to respond to the matter of sea water salinity 4500 years ago, we have been pulling out of the last stage of the Pleistocene ice age for the last 12000 years. The ice extent 4500 years ago was largely melted but still slightly greater than today. Consequently the average surface ocean salinity would have been marginally &lt;em&gt;more&lt;/em&gt; saline than at present, not less!&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2015-10-27T10:31:59.687" LastActivityDate="2015-10-27T10:31:59.687" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6794" PostTypeId="2" ParentId="6788" CreationDate="2015-10-27T06:11:06.563" Score="5" Body="&lt;p&gt;As Peter correctly responds, for sedimentary rocks the principle of superposition is pretty much watertight except where tectonic superposition takes place. The latter can either repeat the sedimentary sequence, overturn it, or overthrust earlier sequences. There are many possible geometries, which creationists tend to misrepresent. The principle of superposition is not an assumption. It is a logical deduction, repeatedly validated by field observation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whilst I note that the questioner doesn't want to get into discussion over creationism, as an Earth scientist who has studied creationist literature for decades, I must warn all readers that creationist literature, as it pertains to the Earth Sciences, is replete with misconceptions, distortions, quotations out of context, cherry-picking of data to give false impressions, and willful disregard of contrary evidence. Therefore, be &lt;em&gt;very&lt;/em&gt; careful what you read, and check it out against genuine science! &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-27T06:11:06.563" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6795" PostTypeId="2" ParentId="4577" CreationDate="2015-10-27T06:25:12.410" Score="3" Body="&lt;p&gt;The Earth has a 4.6 billion year history involving proto-planet collision, meteorite bombardment during the Hadean Era, and an early molten phase when massive scale differentiation took place. We have good reason to believe that the earliest rocks, from which the Earth was formed by accretion, were meteorite in composition . Many of these are stony meteorites containing 'chondrules', i.e. millimetre-sized spherical droplets which were flash melted to more than 1500 deg C, probably by being 'cooked' in close proximity to a supernova explosion. These chondrules were probably formed one or two million years before being incorporated into the rocky meteorites where we now find them. Therefore, I would nominate these as being the first known rocks of the terrestrial rock cycle. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-27T06:25:12.410" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6796" PostTypeId="2" ParentId="6788" CreationDate="2015-10-27T08:50:31.860" Score="6" Body="&lt;p&gt;Here is another example where the law of superposition breaks. Mind you this is a natural process: meteorite impacts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A meteorite impact will excavate material from the bottom, and deposit it above the crater rims. Here's how:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/r3CmZ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/r3CmZ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This will result in something that looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1yEp7.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1yEp7.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source for both images is &lt;a href=&quot;http://www.lpi.usra.edu/exploration/education/hsResearch/crateringLab/lab/&quot; rel=&quot;noreferrer&quot;&gt;http://www.lpi.usra.edu/exploration/education/hsResearch/crateringLab/lab/&lt;/a&gt; - see that website for full copyright info and more in depth explanations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A very famous example of this inverted stratigraphy is &lt;a href=&quot;https://en.wikipedia.org/wiki/Meteor_Crater#Geology&quot; rel=&quot;noreferrer&quot;&gt;Meteor Crater, AZ&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-10-27T08:50:31.860" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6797" PostTypeId="2" ParentId="6791" CreationDate="2015-10-27T09:08:39.843" Score="2" Body="&lt;p&gt;I'd like to add to Gordon's answer by emphasising that a geological map (in the classical case of mapping rock outcrops in colour) is an interpretation of the surface, occasionally with the aid of other methods such as drilling or geophysics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Being an interpretation, the amount of detail varies. One map can say that one area is just a huge block of granite, while another will say that this area is composed of various rock types and features. Would you consider the first one as a map? Or the second? There is no absolute answer to your question.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-10-27T09:08:39.843" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6798" PostTypeId="1" CreationDate="2015-10-27T10:23:58.990" Score="2" ViewCount="298" Body="&lt;p&gt;ERA Interim reanalysis &lt;a href=&quot;http://apps.ecmwf.int/datasets/data/interim-full-daily/levtype=sfc&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://apps.ecmwf.int/datasets/data/interim-full-daily/levtype=sfc&lt;/a&gt; surface level variables such as radiation and precipitation, but also many others, are only available at time 0:00 and 12:00, and not available at step 0? I need 6-hour data and from what I understand regarding the step option, I want step 0 as I need data valid for the same time. &lt;a href=&quot;https://earthscience.stackexchange.com/questions/6706/what-is-the-meaning-of-step-in-era-reanalysis-data&quot;&gt;What is the meaning of step in ERA reanalysis data?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will use this data in a forest modeling simulation that needs 6-hour data.&lt;/p&gt;&#xA;" OwnerUserId="3061" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2017-03-23T14:41:26.153" Title="Why is radiation and total precipitation not available in ERA Interim Reanalysis at step 0?" Tags="|atmosphere-modelling|reanalysis|era|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6799" PostTypeId="2" ParentId="5452" CreationDate="2015-10-27T11:07:01.330" Score="4" Body="&lt;p&gt;Addis Ababa lies 9 degrees north of the equator at about 2300 metres in altitude. Its' mean annual rainfall is about 1090 mm, with an average daily  probability of rain of about 41%. The inter-tropical convergence zone in this part of East Africa is a little anomalous, but sufficient to bring long rains in July-August, and short rains in March-April. Given the altitude, latitude and synoptic climatology, there is nothing unusual about this rainfall, though as Kwinkunks points out, if you happen to hit an unusually wet 'long rainy season' it might &lt;em&gt;seem&lt;/em&gt; unusually wet.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-27T11:07:01.330" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6800" PostTypeId="1" AcceptedAnswerId="6802" CreationDate="2015-10-28T06:16:52.300" Score="13" ViewCount="3191" Body="&lt;p&gt;Many accounts claim that the &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_magnetic_field&quot;&gt;Magnetic Field&lt;/a&gt; of the Earth has been seriously degrading for the past centuries and we are currently in the process of the so called Polar Shift. How likely would it be for Earth to experience this phenomenon. Is it really possible? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would be the possible effect to human beings if this happens?&lt;/p&gt;&#xA;" OwnerUserId="4711" LastEditorUserId="-1" LastEditDate="2015-10-28T15:15:55.583" LastActivityDate="2022-01-20T00:20:10.537" Title="Is it possible for Earth to experience Polar Shift?" Tags="|earthquakes|geomagnetism|electromagnetism|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6801" PostTypeId="2" ParentId="6800" CreationDate="2015-10-28T07:30:54.653" Score="10" Body="&lt;p&gt;Yes, it is not just possible, but highly probable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Detailed palaeomagnetic data have revealed how the Earth's magnetic field changes in a polarity shift. In relative terms (time scale inaccurately known) there is a slow decrease to &amp;lt;10% of the normal field intensity. After an uncertain interval the field intensity picks up to some 20 or 30% of the normal field intensity during a relatively brief spike. Then another low field intensity interval, and finally it picks up to full field intensity - of either normal or reversed polarity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This has never happened in real-time during the scientific era, so the effects are necessarily speculative. Amongst the expected effects would be:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Vulnerability of satellites, power lines and communications to the effects of solar storms.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Increased UV, and hence increased incidence of skin cancer.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;All sorts of changing physico-chemical processes in the upper atmosphere, of which the weakening ozone layer would be the most alarming.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;On average these magnetic flips occur about every 11,000 to 12,000 years - although there is a great deal of variation. On this basis the next one is about due.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It won't be lethal. Neanderthals, Denisovans and Hom.sap's prehistoric forebears survived the last magnetic flip, but it will be inconvenient, and probably not without a serious health impact.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="-1" LastEditDate="2015-10-28T12:49:51.093" LastActivityDate="2015-10-28T12:49:51.093" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="6802" PostTypeId="2" ParentId="6800" CreationDate="2015-10-28T07:43:26.197" Score="15" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is it possible for Earth to experience Polar Shift?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes, and it has happened before.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the past 80 million years it happened over 150 times. The last time this happened was around 800 thousand years ago. A quick note about what a polar shift is, more properly termed a &lt;em&gt;geomagnetic reversal&lt;/em&gt;. Earth's magnetic is such that a compass points to a certain direction. For example, a modern compass would point north. In a reversal, it would point south instead because the poles are reversed. Without going too much into detail, this occurs not by spinning of the poles but rather by decreasing in intensity until it becomes negative, thus reversing the poles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another important thing is the intensity. A strong magnetic field shields Earth's from some kinds of radiation, for example the stuff you can see in Gordon's answer. However, a reversed but strong magnetic field is just as fine. What you should be worried about is the change in the intensity of the field, and this is going up and down all the time, quite rapidly as you can see in the following figure:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3zS9I.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3zS9I.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The black bit (called Brunhes) is now - when the magnetic field is &quot;normal&quot;. The white field in the bottom is more than ~780 thousand years ago, when it was reversed (called Matuyama). As you can see, even though the magnetic field has been normal though this entire time, the intensity went up and down. So yes, a reversal would mean that at one point the intensity would be very low, but this can happen even without a reversal.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What would be the possible effect to human beings if this happens?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In contrast to what some people on the Internet claim, there would be no earthquake or volcanoes or other scary stuff related to it. This is simply not how this works. Also, mass extinctions from the geological history are not correlated with geomagnetic reversals, so you can take that worry off your mind. What can happen is detailed in a good way in Gordon's answer. Nothing too scary.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Magnetic Field of the earth is seriously degrading for the past centuries and we are currently in the process of the so called Polar Shift&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not necessarily. It seriously degraded many times before without associated geomagnetic reversals.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2015-10-28T07:56:44.773" LastActivityDate="2015-10-28T07:56:44.773" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6803" PostTypeId="1" CreationDate="2015-10-28T19:56:56.063" Score="2" ViewCount="55" Body="&lt;p&gt;I like the rock garden and accompanying display outside the Berkeley geology building -- where else are there exhibits on rock types or on geological processes?&lt;/p&gt;&#xA;" OwnerUserId="4611" LastEditorUserId="4611" LastEditDate="2015-10-28T22:28:38.267" LastActivityDate="2015-10-28T22:55:10.710" Title="What geology-related displays at museums, universities, etc. in California are especially well-done and enlightening?" Tags="|geology|" AnswerCount="1" CommentCount="1" ClosedDate="2015-10-29T10:32:18.293" ContentLicense="CC BY-SA 3.0" />
  <row Id="6804" PostTypeId="2" ParentId="6803" CreationDate="2015-10-28T22:38:39.957" Score="2" Body="&lt;p&gt;Alas, you live in the wrong era. In the 1960s and 1970s by far the best and most informative was the geological museum in South Kensington (West London). Sadly, it is now dumbed-down - sacrificed on the alter of children's populism. The Colorado School of Mines geology museum is reckoned to one of the best, especially for minerals. Otherwise, I can't speak for America, but if you are ever in Vienna you must visit their Natural History Museum where the mineralogy and meteorite galleries are gob-smacking superb. The Natural History Museum in Adelaide, South Australia has the world's best exhibit of Eocambrian fauna, and also boasts a spectacular opalized plesiosaur. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-28T22:38:39.957" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6806" PostTypeId="1" CreationDate="2015-10-29T02:42:31.133" Score="4" ViewCount="141" Body="&lt;p&gt;I know that the upper limit of radiocarbon dating is typically about 60,000 years, but how many radiocarbon dates have actually been measured? As of October 2015, how many $^{14}\ce C$ (radiocarbon) measurements have been made worldwide, how many have been calibrated by historic dates, and what proportion of measurements have yielded inconsistent results?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="20" LastEditDate="2015-11-03T03:41:22.927" LastActivityDate="2015-11-03T03:41:22.927" Title="How many $\ce{^{14}C}$ measurements have been made?" Tags="|isotopic|dating|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="6807" PostTypeId="1" AcceptedAnswerId="6814" CreationDate="2015-10-29T05:10:21.430" Score="3" ViewCount="2747" Body="&lt;p&gt;Say a Mars size object hits the Earth in such a way that it knocks the Earth in a straight 0 degree angle, and let's assume that we somehow do not go extinct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would happen to the poles in this scenario, in terms of temperature and volume of ice?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My guess is since now there is no longer a tilt, the poles would receive the same amount of solar input, which would increase the ice caps of both poles.&lt;br /&gt;As there is no incentive to melt the caps, maybe this would even cool the planet.&lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="595" LastEditDate="2015-10-29T15:37:23.250" LastActivityDate="2015-10-30T04:00:44.230" Title="Effect on poles when Earth is not tilted" Tags="|geophysics|geology|climate|" AnswerCount="2" CommentCount="3" ClosedDate="2015-10-30T17:22:42.693" ContentLicense="CC BY-SA 3.0" />
  <row Id="6808" PostTypeId="2" ParentId="530" CreationDate="2015-10-29T06:27:40.293" Score="2" Body="&lt;p&gt;Though both the inner and outer core are made of the same material, the melting point of inner core is increased due to the increased pressure, so the inner core is in a solid state and outer is a liquid .&lt;/p&gt;&#xA;" OwnerUserId="4721" LastEditorUserId="94" LastEditDate="2015-10-29T08:19:21.813" LastActivityDate="2015-10-29T08:19:21.813" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6809" PostTypeId="2" ParentId="6807" CreationDate="2015-10-29T06:34:48.090" Score="2" Body="&lt;p&gt;The question is not very clear, but if a Mars sized object were to collide with Earth, at any angle, believe me, that would be an undoubted total extinction event for every organism on the planet. You can do a 'back of an envelope' calculation on the kinetic energy expended by such an impact. That is, E=1/2M.V^^2, where M and V are the mass and relative velocity of the impacting bolide. Then express that as thermal energy - very obviously there wouldn't be any ice left on Earth's surface. There probably wouldn't be much left of any oceans or continents either. Much of the planetary debris would be flung into space, with some being lost, some condensing into another moon (or multiple moons), and some raining down on the planet in a new 'Hadean' event. The entire geochemical distribution of the atmosphere, oceans, crust, mantle and core, would be back into the melting pot (literally) and would take between a few hundred thousand and a few million years to re-equilibrate into something resembling a normal planet. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But to address the tilt problem, if the spin axis was orthogonal to the incoming solar radiation, the nett annual insolation at the poles wouldn't change - only the seasonal distribution. Without the seasons the entire heat distribution of the planet would be radically changed, and it is impossible to estimate the myriad knock-on effects without extensive modelling on a supercomputer, and then drawing a consensus from 20 to 30 of the most sophisticated global climatic models. For example, the cloud distribution, ocean current strengths, polar vortices, rainfall distribution, river flows, groundwater storage, tropical storm distribution and frequency, CO2 absorbtion by vegetation, and many other co-variables would all be affected. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2015-10-29T06:55:31.363" LastActivityDate="2015-10-29T06:55:31.363" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6810" PostTypeId="2" ParentId="530" CreationDate="2015-10-29T08:49:00.333" Score="6" Body="&lt;p&gt;Just to add to Dave's answer, the above phase diagrams give the illusion of high precision. In fact, in addition to the temperature distribution, we are not even entirely sure how many sub-solidus phases there are. See for example, Ahrens et al: &lt;a href=&quot;http://web.gps.caltech.edu/~sue/TJA_LindhurstLabWebsite/ListPublications/Papers_pdf/Seismo_2069.pdf&quot; rel=&quot;noreferrer&quot;&gt;http://web.gps.caltech.edu/~sue/TJA_LindhurstLabWebsite/ListPublications/Papers_pdf/Seismo_2069.pdf&lt;/a&gt; &#xA;Moreover I was rightly corrected, in a previous answer, when I asserted that the core composition is Ni-Fe with a large sulphur impurity. In fact, although I was probably correct, there is plenty of scope for S2, Ni and other heavy metals, H2, OH-, and other impurities in the core, at unknown concentrations, most of which can create a eutectic depression of the solidus line - that is, shifting the liquid-solid boundary down-temperature. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-29T08:49:00.333" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6811" PostTypeId="2" ParentId="2481" CreationDate="2015-10-29T16:24:34.457" Score="5" Body="&lt;p&gt;According to &quot;&lt;a href=&quot;http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.458.3927&amp;amp;rep=rep1&amp;amp;type=pdf&quot;&gt;Evaporation from a Small Lake in the&#xA;Continental Arctic using Multiple Methods&lt;/a&gt;&quot; &lt;em&gt;Nordic Hydrology&lt;/em&gt;, 27, 1996, 1-24:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Drainage from Contwoyto Lake occurs through the Burnside River and Back River&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, yes, to Bathurst Inlet via the Burnside River and to Chantrey Inlet via the Back River.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can trace out the two paths on the following topo map: &lt;a href=&quot;http://en-ca.topographic-map.com/places/Contwoyto-Lake-947046/&quot;&gt;http://en-ca.topographic-map.com/places/Contwoyto-Lake-947046/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Back River outlet is at the south end of the lake and flows through a series of smaller lakes.  &lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2015-10-29T16:24:34.457" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6812" PostTypeId="2" ParentId="4663" CreationDate="2015-10-29T20:22:35.390" Score="2" Body="&lt;p&gt;Just throwing  some thought on the subject, it is easy to me to understand that there is a big pump moving large amount of water from one pole to the opposite one along the year, that is during summer in north hemisphere the ice melts at Arctic and mix to the sea; at the same time water start precipitating more and more on the Antarctica, piling up as snow and ice.  During the other six months the pump reverts, moving water from Antarctica to the Arctic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this hypothetical situation this pump will behave differently.   The water will evaporate from the sea, and precipitate towards the poles.   Those rain in midway to the pole would provide vegetation life, erosion, and all sort of things rain water does.   That water falling in the north and south pole would have no reason, in principle, to melt and reinsert in the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the rain started to fall mostly on high latitudes, possibly the region around equator would be more exposed and deserter, increasing the heat, evaporation, and the convection of the air at high speed.   Possibly very intense winds blowing everything, moving quickly the clouds and vapor to higher latitudes, where the rain would fall.   Anyway, the hotter atmosphere should increase the loss of the lighter gases to the space due to kinetic energy gain, decreasing the atmosphere pressure little by little while becoming hotter.  In this loss there could be even some water vapor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then I think that in the long run the water would tend to move all the way to the poles draining drastically the remaining of the planet.  If we think of an ocean as salty (3.5%) as ours, possibly there would be deposition of large layers of salt, most of it sodium chloride. I don't really know if there would be a &quot;life zone&quot; around some high latitude.  Certainly tropic would have no meaning in this configuration.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is the &quot;big picture&quot;, but not all the story.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We have different wind flow in atmosphere and water flow in the oceans due to others factors.   One of those being the tides that move water in waves half circumference of the planet.   The main component being that from the moon, but we have other of smaller intensities like the solar influence.  Other factors are the convection due difference temperatures and pressures, and Coriolis force making it go round in its trip across latitudes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another factor is that we have a non homogeneous distribution of mass on planet surface, the removal of large amount of water, moved to the poles, possibly would increase the amount of wobbling, then the precession ( &lt;a href=&quot;https://en.wikipedia.org/wiki/Axial_precession&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Axial_precession&lt;/a&gt;) of the planet.   Perhaps this wobbling would be responsible to a certain amount of melting at the poles, keeping the pumping working longer and, who knows, preserving some life in the planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A hotter atmosphere could increase the amount of clouds, if it covers all the planet we could have a very long freezing of the planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we think on a dry planet with water moved to poles as ice, we could perhaps include sublimation of ice in the figure, adding the loss of water to space due to  heating of the atmosphere.   I don't think we would become a Mars, our gravity is about three times Mar's gravity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;HTH&lt;/p&gt;&#xA;" OwnerUserId="3269" LastActivityDate="2015-10-29T20:22:35.390" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6814" PostTypeId="2" ParentId="6807" CreationDate="2015-10-30T04:00:44.230" Score="3" Body="&lt;p&gt;If we ignore the giant impact (which would have enormous effects), and just look at the effect of the Earth having a 0 degree axial tilt, the most immediately apparent effect is that the seasons would be reduced almost to nothing and the very small seasons that remain would be planet wide, not alternating between the 2 hemispheres. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth is currently closest to the sun in the first week of January and furthest in the first week of July.  &lt;a href=&quot;http://www.timeanddate.com/astronomy/perihelion-aphelion-solstice.html&quot; rel=&quot;nofollow&quot;&gt;Source&lt;/a&gt;, so it's pretty obvious that being closer to the sun doesn't create summer.  The axial tilt is what causes the seasons, but the change in distance to the sun still has some effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's a little  over 3% variation in distance, see &lt;a href=&quot;https://en.wikipedia.org/wiki/Sunlight#Intensity_in_the_Solar_System&quot; rel=&quot;nofollow&quot;&gt;source&lt;/a&gt;, yielding a bit over 9% variation in energy received between the Earth's perihelion and aphelion, but that doesn't mean a 9% change in temperature.  It's much smaller than that due to the Earth's oceans, atmosphere and to a lesser extent, surface are all heat sinks that take a long time to warm up or cool down.   The seasonal difference in temperature would be much less than that.   Maybe a few degrees, perhaps 5-10 degree difference between summer and winter, probably less than the change between night and day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No tilt also means, you lose the 6 months of sunlight, 6 months of darkness that we currently get near the poles and the sun wouldn't be higher in the sky in summer than in winter.    At the poles, you'd effectively get sunset, 24 hours a day, 365 days a year but over most of the Earth you'd have 12 hours (and a few minutes) of sunlight and nearly 12 hours of, not darkness, cause you'd still have twilight and dawn, but over the most of the planet, it would be 12 hour days pretty much.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The poles would receive less solar energy and could be colder and there wouldn't be a spring thaw or summer growth.  Plant Growth would be pretty consistent all year around.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The equator would have more peak sun and could be hotter.  With our current tilt, the pole to equator solar energy ratio is 0.4 to 1.  &lt;a href=&quot;http://hyperphysics.phy-astr.gsu.edu/hbase/astro/orbtilt.html&quot; rel=&quot;nofollow&quot;&gt;Source&lt;/a&gt;.  With no tilt, it would be 0 to 1.  The poles could see an increase in permanent ice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But, despite that increase in ice, you'd get a decrease in solar-ice-reflection, so that could mean a warmer earth, even with more ice on both poles.   The equatorial region could be hotter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Circulation is hugely complex, so that's a great big wild-card.   Seasonal driven ocean and air currents would be greatly reduced but temperature driven currents should increase, though the reduction of temperature variation is difficult to predict.  You still get night to day temperature variation, but the overall effect on wind and ocean currents is too hard for me to predict. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hyper-physics says the tilt is essential to life (linked above).  I'm not sure that's true, but no seasons and potentially reduced circulation due to more consistent temperatures could have a pretty big effect.   The potentially worst outcome could be a significant still water in the oceans which could create large dead zones.  That's by no means a certainty, but it's possible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://science.nasa.gov/science-news/science-at-nasa/2004/05mar_arctic/&quot; rel=&quot;nofollow&quot;&gt;Article&lt;/a&gt; on the effects of the ocean conveyor belt stopping, if interested.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I missed anything, comments are welcome.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2015-10-30T04:00:44.230" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6815" PostTypeId="1" CreationDate="2015-10-30T05:50:23.863" Score="2" ViewCount="1225" Body="&lt;p&gt;I got some sand out of a river bed and moved a magnet through it. Some of the particles I picked up were definitely small crystals of magnetite, but a lot of others were small, round brown rocks that did not look like magnetite at all.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I thought the only thing commonly found in country rock that was magnetic was magnetite. Does this mean the small brown rocks have magnetite crystals somewhere inside of them?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2015-10-30T11:22:01.640" Title="Magnetic rocks no magnetite" Tags="|geology|rock-magnetism|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6816" PostTypeId="2" ParentId="6815" CreationDate="2015-10-30T08:58:18.780" Score="3" Body="&lt;p&gt;Broadly speaking you are correct on both counts: magnetite is the most magnetic mineral, and it can oxidize, first to the matastable phase maghemite, and ultimately to the fully oxidized haemetite. This process can yield grains with a zoned appearance, both in hand specimen and more clearly under the microscope, with brown on the outside and residual black magnetite in the core. Maghemite, as the name suggests, is also magnetic. There are several other moderately to strongly magnetic minerals, closely related to magnetite, and with a similar molecular structure. For example ilmenite, a very common mineral that sometimes occurs with magnetite, is the double oxide of iron and titanium. Tantalite / columbite, or manganotantalite $(Fe, Mn)(Ta, Nb)_2O_6$ is not as magnetic as magnetite but may still be magnetic enough to swing a compass needle. It looks identical to magnetite, but can have a slightly purplish brown sheen. Similarly, chromite, the double oxide of chromium and iron, can be very magnetic, but I don't recall ever seeing anything other than black chromite. Franklinite, which is reddish purple, is another mineral of the magnetite group, and is a complex oxide of zinc,iron and manganese. There are several other weakly magnetic minerals of the magnetite group, most of which are quite rare. As a rough rule of thumb, the more oxidized or the more iron is replaced with some other metal, the less magnetic it is. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS, if you ever find metallic looking sand that is magnetic, stake a claim! Platinum is also weakly magnetic.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="2470" LastEditDate="2015-10-30T11:22:01.640" LastActivityDate="2015-10-30T11:22:01.640" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6817" PostTypeId="2" ParentId="4994" CreationDate="2015-10-30T09:29:07.883" Score="3" Body="&lt;p&gt;David LeBauer is correct in saying that there are 'allometric equations' to estimate the leaf biomass, but they only refer to small experimental plots in such places as Hawaii, Japan, Singapore and Malaysia. The number of species involved is a few dozen at most. As 'N9ZN' points out, trying to develop generalizations would be a titanic task, and essentially impossible without a vast amount of experimental work. There are about 50,000 tree species in the tropics alone, each with its own calibration curve, not to mention ecologic, microclimatic and nutrient constraints upon leaf development. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would suggest that, instead of trying to develop a deterministic result, since leaf biomass is approximately related to potential evapotranspiration and water availability/constraints, it would be easier to estimate average water usage by stem dendrometry, crunch the numbers for ET0 based upon climatic data, and then develop a biomass conversion efficiency. As far as I know, this hasn't yet been done, at least on anything other than a very small scale - but theoretically it should be doable. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-30T09:29:07.883" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6819" PostTypeId="2" ParentId="6806" CreationDate="2015-10-30T18:35:02.830" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;How many have been validated by historic calibration, and what&#xA;  proportion (if any) yielded inconsistent results?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Often with an item that they want tested, a specific date isn't available so calibration isn't possible, but calibration can be done when dates are known.  Tree rings are most common and (though I've not read of this being done), samples from dead bodies from a specific battle or disease outbreak where a date of death is known.  Article &lt;a href=&quot;https://c14.arch.ox.ac.uk/embed.php?File=calibration.html&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Calibration_of_radiocarbon_dates&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The calibration curve represents changes in the amount of C-14 present in the atmosphere which is also a factor.   There wouldn't be a charted curve if calibration hadn't been done quite extensively (see 2nd article above).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's some room for bacterial or other &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiocarbon_dating#Contamination&quot; rel=&quot;nofollow&quot;&gt;contamination&lt;/a&gt;, especially with older objects, and contamination has lead some inconsistent results but that's not because the theory isn't sound but because of miss-handling.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2015-10-30T18:35:02.830" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6820" PostTypeId="1" AcceptedAnswerId="6909" CreationDate="2015-10-30T19:25:31.260" Score="3" ViewCount="326" Body="&lt;p&gt;The UAH 6.0 and RSS lower troposphere data sets line up nearly perfectly and both show no significant warming for over 20 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the leading theory for what's going on? What explains this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Ofs52.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ofs52.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4644" LastActivityDate="2015-11-13T08:28:44.760" Title="UAH and RSS Lower Troposphere data" Tags="|climate-change|troposphere|" AnswerCount="1" CommentCount="19" ContentLicense="CC BY-SA 3.0" />
  <row Id="6821" PostTypeId="2" ParentId="6750" CreationDate="2015-10-30T22:44:06.313" Score="2" Body="&lt;p&gt;Concerning datasets, there are several, depends on Your final purpose.&lt;/p&gt;&#xA;&lt;p&gt;One of the simplest is &lt;a href=&quot;http://www.osi-saf.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;output from OSI-SAF&lt;/a&gt;, which has info about Sea Ice edge, concentration, type, emissivity and drift. It is derived mostly from polar orbiting meteorological satellites, I guess.&#xA;More detailed info can be found on &lt;a href=&quot;http://arctic.atmos.uiuc.edu/cryosphere/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Univ of Illinois pages&lt;/a&gt;&#xA;Visual images from  &lt;a href=&quot;http://modis-snow-ice.gsfc.nasa.gov/?c=MOD29&quot; rel=&quot;nofollow noreferrer&quot;&gt;MODIS satellites&lt;/a&gt;can be handy&lt;/p&gt;&#xA;&lt;p&gt;But, most detailed info about sea ice conditions can be derived with radar satellites, with commercial options like &lt;a href=&quot;http://www.asc-csa.gc.ca/eng/satellites/radarsat/&quot; rel=&quot;nofollow noreferrer&quot;&gt;radarsat&lt;/a&gt; being available. From free sources, data from &lt;a href=&quot;http://www.esa.int/Our_Activities/Observing_the_Earth/Copernicus/Sentinel-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sentinel-1&lt;/a&gt; is available since late 2014.&lt;/p&gt;&#xA;&lt;p&gt;So the best info is available from satellites, in-situ measurements do not cover most of the area.&lt;/p&gt;&#xA;&lt;p&gt;Our knowledge of Arctic sea ice is pretty good IMO, at least since 1979 when satellites started to measure the extent. Understanding the age of sea ice is a bit more tricky, as it can be up to ten, maybe even few more years&#xA;old.&lt;/p&gt;&#xA;" OwnerUserId="3385" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-10-30T22:44:06.313" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6823" PostTypeId="2" ParentId="5135" CreationDate="2015-10-31T03:45:37.907" Score="1" Body="&lt;p&gt;I don't have a definitive answer, but here is a suggestion you might look into: A large bolide will always have a large impact velocity because of the M1 x M2 proportionality of gravitational attraction. A high velocity means that the non-directional dissipation of kinetic energy will far exceed the directional momentum, resulting in a circular or nearly circular crater. A small impactor, on the other hand, may or may not be fast. In the event of a relatively low velocity, the momentum will be relatively large compared to the kinetic energy. Hence, depending upon the angle of impact, it may leave a slightly to very elongated crater. At one extreme, some of the craters in the northern Canadian shield are almost trenches rather than craters. So concentrate on the smaller craters and do a statistical analysis of the crater's eccentricity. If they are nearly all circular then they are probably volcanic; if there is a significant fraction of elliptical craters, especially with high eccentricity, then they are probably of impact origin. Also check for strongly directional patterns of ejecta from the smaller craters. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-31T03:45:37.907" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6824" PostTypeId="2" ParentId="5071" CreationDate="2015-10-31T04:26:53.653" Score="2" Body="&lt;p&gt;There isn't much to choose between them. They are both variants of the same general equation. They both take account of the three main variables: temperature, rate of advective removal of moisture (proportional to surface wind velocity), and difference in vapour pressure (which can be related to humidity). In countries using SI units there are several other evaporation equations along similar lines Some other equations do not take adequate account of advection (the 'v' parameter), and hence I would advise against using such equations. &#xA;Strictly, the best equation, favoured by FAO, and in a slightly modified form by the American society of Civil Engineers, is the classic Penman-Monteith equation:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/eXgHc.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eXgHc.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;from &lt;a href=&quot;https://en.wikipedia.org/wiki/Penman%E2%80%93Monteith_equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Penman%E2%80%93Monteith_equation&lt;/a&gt;&#xA;But this is a pain to calculate, so most people, including myself, put it in the 'too hard basket'. &#xA;Whatever equation you decide to use on your spreadsheet, be aware of potential errors from ground conduction (underestimate of E), higher salinity (depresion of E), and boundary effects, especially in areas of high advective exposure. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-10-31T04:26:53.653" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6825" PostTypeId="2" ParentId="6525" CreationDate="2015-10-31T08:16:31.450" Score="4" Body="&lt;p&gt;Yes, you are correct in your calculation. However, the most common hydrated calcium phosphate in nature is indeed hydroxyapatite. Note that industrially, there are several other calcium phosphates (see &lt;a href=&quot;https://en.wikipedia.org/wiki/Calcium_phosphate#Calcium_phosphates&quot; rel=&quot;nofollow&quot;&gt;link&lt;/a&gt;, note that none of them is your calcium phosphate) The reason that it forms instead of the &quot;simpler&quot; mineral is that it is more stable thermodynamically. I'm not certain about the exact reasons for that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apatite is so stable that in nature and rocks, almost whenever you have phosphate, it binds with calcium to form apatite. The only way to not have apatite is to not have calcium, not have phosphate, or have some really exotic system that suppresses its formation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is also known experimentally. In &lt;a href=&quot;http://dx.doi.org/10.1180/minmag.1966.036.276.06&quot; rel=&quot;nofollow&quot;&gt;experiments&lt;/a&gt; that &lt;a href=&quot;http://dx.doi.org/10.1180/minmag.1967.036.280.08&quot; rel=&quot;nofollow&quot;&gt;simulated&lt;/a&gt; calcium phosphate systems as early as the 60s, it was hard to crystallise anything but apatite.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-10-31T08:16:31.450" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6826" PostTypeId="2" ParentId="4301" CreationDate="2015-10-31T08:37:55.150" Score="1" Body="&lt;p&gt;I'd like to add to Fred's answer, which is correct. Some more points:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If I correctly understand the $\ce{SiO_2}$ contained in the rock as a&#xA;  part of a mineral other than pure $\ce{SiO_2}$, for ex. the&#xA;  $\ce{Si_2O_4}$ part of anorthite $\ce{CaAl_2Si_2O_8}$, is calculated&#xA;  into the quantity of total silica.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is not correct. When calculating that acidic or basic character of a rock, you have to take into account the entire rock, in what is known as a &quot;whole rock&quot; or &quot;bulk rock&quot; composition. You don't separate $\ce{SiO_2}$ of various minerals in the calculation.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What I cannot understand at all is whether mass or volume is taken into account.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As a general rule of thumb, rock and mineral chemistries are usually calculated using mass (commonly known as weight in the literature) or molar proportions, and rarely if ever as volume.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, I have never seen the per/meso/hypo silicic terms used in the professional literature (or any other literature for that matter). Apart from that, the term acidic originated long long time ago when it was thought that silica was present in the rocks as silicic acid. This is now known to be false, and in the past decades the terms acidic and basic are falling out of use. Silicic and mafic are more common nowadays. Note that obviously, this only works for igneous or metamorphic silicate rich rocks. You would not use that to describe rocks that are very poor in that stuff such as carbonatites, or sedimentary rocks such as phosphorites or evaporites.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-10-31T08:37:55.150" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6828" PostTypeId="2" ParentId="6782" CreationDate="2015-10-31T15:47:57.370" Score="4" Body="&lt;p&gt;Some books are about specific parts of the Andes, for example - &lt;a href=&quot;http://ebooks.geoscienceworld.org/content/the-geology-of-chile&quot; rel=&quot;nofollow&quot;&gt;The Geology of Chile&lt;/a&gt; (Mareno and Gibbons - editors). This book represents a culmination of research in tectonics, geology and such from researchers across Chile.  Given the location of Chile, this is definitely an apt reference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A comprehensive resource is the book &lt;a href=&quot;http://www.scielo.cl/scielo.php?pid=S0716-02082000000200006&amp;amp;script=sci_arttext&quot; rel=&quot;nofollow&quot;&gt;Tectonic Evolution of South America&lt;/a&gt; (edited by Cordani et al. 2000), this brings together data, information and observations from dozens of scientists across South America. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A paper that is involves a study related to your query is &lt;a href=&quot;http://www.colorado.edu/geolsci/courses/GEOL5700-9/pdf/Spring07/Geol95HoornColombiaAndesDrainage.pdf&quot; rel=&quot;nofollow&quot;&gt;Andean tectonics as a cause for changing drainage patterns in&#xA;Miocene northern South America&lt;/a&gt; (Hoorn et al. 1995) - this looks at the palaeodrainage of the northern portion of South America in the relation to the mountain building and tectonics of the region at that time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another paper, is &lt;a href=&quot;http://sp.lyellcollection.org/content/142/1/1.full.pdf&quot; rel=&quot;nofollow&quot;&gt;The proto-Andean margin of Gondwana: an introduction&lt;/a&gt;, this introductory paper reviews the evidence for Andean tectonics and palaeotectonic regimes, stretching back to the Neoproterozoc. &lt;/p&gt;&#xA;" OwnerDisplayName="user4727" LastActivityDate="2015-10-31T15:47:57.370" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6830" PostTypeId="1" CreationDate="2015-11-01T11:35:44.827" Score="5" ViewCount="142" Body="&lt;p&gt;The concept of 'return period' (= 'average recurrence interval', or ARI) is widely used in hydrology, and to a much lesser extent in geology, geomorphology, geophysics, etc. Whatever the application, the traditional analysis is predicated upon 'stationarity of the data-set'. However, in this new era of climate change the hydrologic data set is, by definition, no longer 'stationary'. That is, the underlying statistical parameters are no longer consistent. Therefore, a new methodology is required to take account of the drift in climatic means, extremes, revised frequencies, etc. Are there any first attempts to deal with this problem?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4487" LastEditDate="2015-11-05T08:24:51.873" LastActivityDate="2016-01-10T10:54:47.833" Title="Are 'Return Periods' being recalculated? If so, how?" Tags="|climate-change|climate-models|statistics|database|predictability|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="6831" PostTypeId="1" CreationDate="2015-11-01T20:56:50.843" Score="5" ViewCount="32" Body="&lt;p&gt;My understanding is that some minerals with layered crystal structures will reversibly absorb water with changes in humidity. Are there any minerals where this reversible absorption leads to a stacking-sequence change in the crystal structure?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By stacking-sequence change, I mean that the relative alignment of atomic layers shifts, such as in the image below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dC5vf.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dC5vf.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4731" LastEditorUserId="4487" LastEditDate="2015-11-01T22:27:59.440" LastActivityDate="2015-11-01T22:27:59.440" Title="Can humidity changes induce stacking-sequence changes?" Tags="|geochemistry|mineralogy|humidity|crystallography|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6832" PostTypeId="1" CreationDate="2015-11-02T03:01:57.410" Score="7" ViewCount="104" Body="&lt;p&gt;For a piece of land in Peru (Zone 18K), I was provided the following UTM coordinates (showing just one): 140800 E 8176337 N. However, when I look up the site on Google Earth, while the N coordinate is identical, the E one is 779875.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anybody know what the issue might be?&lt;/p&gt;&#xA;" OwnerUserId="4732" LastEditorUserId="725" LastEditDate="2016-09-10T09:10:21.497" LastActivityDate="2016-09-10T09:10:21.497" Title="Inconsistency between topographic survey and Google Earth" Tags="|cartography|mapping|projection|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6833" PostTypeId="1" CreationDate="2015-11-02T09:08:51.050" Score="5" ViewCount="1032" Body="&lt;p&gt;I'm trying to answer the following question:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Compute the inclination and declination of the magnetic field that would be observed in Boulder, Colorado (40°N, 105°W) if the Earth’s field corresponded to a perfect geocentric dipole whose axis penetrates the Earth’s surface at 80°N, 72°W.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Source: question 4, exercise set 5.10, on p. 360 of Lowrie (2007).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found the inclination using $\arctan(2\tan(40))$, but am unsure of how to get the declination.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Reference:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lowrie, W. (2007). &lt;em&gt;Fundamentals of Geophysics&lt;/em&gt;, 2nd ed. Cambridge University Press.&lt;/p&gt;&#xA;" OwnerUserId="4733" LastEditorUserId="94" LastEditDate="2015-11-02T09:46:40.907" LastActivityDate="2016-01-05T22:38:37.920" Title="Calculating magnetic declination for a non-axial dipole field" Tags="|geophysics|homework|geomagnetism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6834" PostTypeId="2" ParentId="6832" CreationDate="2015-11-02T14:19:56.667" Score="6" Body="&lt;p&gt;&lt;strong&gt;It's almost certainly a difference in the UTM zones.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In most zones, the &lt;a href=&quot;https://www.maptools.com/tutorials/utm/details&quot; rel=&quot;nofollow noreferrer&quot;&gt;minimum easting value&lt;/a&gt; is 160,000 mE and the max is 834,000 mE (at the equator). People sometimes use the 'wrong' zone (i.e. not the zone that the location is actually in) if it's more convenient to use a neighbouring zone for some reason. For instance, maybe I have coordinates for 100 points but a few are in a neighbouring zone; it's probably easier to tolerate the location inaccuracy than to reference them to a different UTM zone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other thing that &lt;em&gt;can&lt;/em&gt; create discrepancies is different datums (e.g. WGS84 in Google Earth, and some other probably local datum for your survey), but that's not what's going on here. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;To sum up, it looks like the coordinates you were given are referenced to Zone 19K, to the east of Zone 18K, so the easting is smaller than the usual minimum. The correctly referenced Zone 18K coordinate is the one in Google Earth.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Last thing: I just want to connect with &lt;a href=&quot;https://earthscience.stackexchange.com/questions/6676/what-is-the-maximum-value-of-easting-in-utm-coordinates/6677#6677&quot;&gt;this related question.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;h3&gt;EDIT: Conversion&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Converting to the correct coordinates is a little risky without knowing exactly how the original coordinates were arrived at. But if they were indeed simply given in UTM Zone 19, then &lt;a href=&quot;http://www.ngs.noaa.gov/TOOLS/utm.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;a round-trip conversion via lat-lon&lt;/a&gt; shows that they are equivalent to 781493.139 mE, 8177491.483 mN in UTM Zone 18. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can confirm this with &lt;a href=&quot;https://pypi.python.org/pypi/pyproj?&quot; rel=&quot;nofollow noreferrer&quot;&gt;PyProj&lt;/a&gt; using the zones' &lt;a href=&quot;http://www.spatialreference.org/ref/epsg/wgs-84-utm-zone-18s/&quot; rel=&quot;nofollow noreferrer&quot;&gt;EPSG codes&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;&amp;gt;&amp;gt;&amp;gt; import pyproj&#xA;&amp;gt;&amp;gt;&amp;gt; x, y = 140800, 8176337  # Zone 19S we think&#xA;&amp;gt;&amp;gt;&amp;gt; utm18_wgs84 = pp.Proj(init='epsg:32718') &#xA;&amp;gt;&amp;gt;&amp;gt; utm19_wgs84 = pp.Proj(init='epsg:32719')&#xA;&amp;gt;&amp;gt;&amp;gt; pyproj.transform(utm19_wgs84, utm18_wgs84, x, y)&#xA;(781493.1384182497, 8177491.482738381)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;So, if that's what originally happened, these new coordinates are what you want.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-11-03T00:32:06.353" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6835" PostTypeId="1" CreationDate="2015-11-02T16:01:41.500" Score="3" ViewCount="64" Body="&lt;p&gt;Is there an adjective to describe data that has areal weight, like area, biomass, population, etc. — data that has to be aggregated by sum for example — vs. data that doesn't, such as landcover classification? &lt;em&gt;Categorical&lt;/em&gt; for the latter, perhaps, but what for the former? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To illustrate &lt;em&gt;aggregation by sum&lt;/em&gt;: if you had rasters of biomass and elevation on 200 m $\times$ 200 m cells, and you wanted to re-scale it to 400 m $\times$ 400 m, you'd give each new, larger cell the average elevation on the 4 smaller cells that comprise it, but the sum of the 4 biomass values.&lt;/p&gt;&#xA;" OwnerUserId="2440" LastEditorUserId="28050" LastEditDate="2015-11-03T13:06:42.733" LastActivityDate="2015-11-03T13:30:46.230" Title="What is the technical term for spatially aggregated measures?" Tags="|remote-sensing|terminology|statistics|cartography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6836" PostTypeId="2" ParentId="6835" CreationDate="2015-11-02T16:33:00.237" Score="3" Body="&lt;p&gt;&lt;strong&gt;Count data.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quantitative data that varies discretely and arbitrarily along some scale can be called &lt;strong&gt;count&lt;/strong&gt; data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nick Chrisman (1995; Beyond Stevens: A revised approach to measurement for geographic information, presented at Auto-Carto; see &lt;a href=&quot;http://mapcontext.com/autocarto/proceedings/auto-carto-12/pdf/beyond-stevens-a-revised-approach-to-measurement.pdf&quot; rel=&quot;nofollow&quot;&gt;this PDF&lt;/a&gt; for a transcript) pointed out that there are many more typologies of measurement than the 'classic' four proposed by Stevens and outlined in Wikipedia's &lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Level_of_measurement&quot; rel=&quot;nofollow&quot;&gt;Typologies of measurement&lt;/a&gt;&lt;/em&gt; article.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;None of the measurement typologies are rigid or prescriptive, but Crisman is not alone in recognizing counts as an important &lt;a href=&quot;https://en.wikipedia.org/wiki/Statistical_data_type&quot; rel=&quot;nofollow&quot;&gt;statistical data type&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Another class of geographic measurements consist of counts aggregated&#xA;  over some region in space. Counts are discrete, since there is no half&#xA;  person to count, but a count captures more mathematical structure than&#xA;  the other discrete levels (nominal and ordinal). &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Mosteller and Tukey also called them &lt;em&gt;counts&lt;/em&gt; (see Mosteller's book, &lt;em&gt;Data Analysis and Regression&lt;/em&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's clear to me that the concept is a good fit for, say, population, but your biomass example seems intuitively less clear-cut. The point is that it's a countable quantity, as opposed to a ratio scale, so it might just be a matter of being careful how you define the term.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;This answer was edited after clarification in the comments.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2015-11-03T13:30:46.230" LastActivityDate="2015-11-03T13:30:46.230" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6837" PostTypeId="2" ParentId="5007" CreationDate="2015-11-02T21:39:56.883" Score="1" Body="&lt;p&gt;Z depends upon convention, but in geophysics we typically use Z=positive downward. R is radial and the positive direction is defined in the direction FROM the source TOWARD the receiver. T polarity can be determined from the right-hand rule once you have Z and R. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For reference, this is the based on the convention for polarity as described by Aki and Richards (1980). &lt;/p&gt;&#xA;" OwnerUserId="2557" LastEditorUserId="2557" LastEditDate="2015-11-04T17:55:24.697" LastActivityDate="2015-11-04T17:55:24.697" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6839" PostTypeId="1" CreationDate="2015-11-03T18:13:21.033" Score="5" ViewCount="8823" Body="&lt;p&gt;I am reading an article on deforestation entitled &lt;em&gt;Tropical Deforestation and Carbon Emissions from PADDD&lt;/em&gt;. Part of the article reads:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If future deforestation rates follow recent trends, PADDDed forests would emit approximately 6.0–10.9 million Mg C by 2100.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What is the meaning of Mg C? Is it milligrams of carbon?&lt;/p&gt;&#xA;" OwnerUserId="4738" LastEditorUserId="28050" LastEditDate="2015-11-03T21:02:16.977" LastActivityDate="2018-06-29T01:25:32.983" Title="What is the meaning of the units Mg C?" Tags="|measurements|biogeochemistry|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6840" PostTypeId="2" ParentId="6839" CreationDate="2015-11-03T18:59:54.363" Score="3" Body="&lt;p&gt;When discussing about the carbon cycle in scientific papers, the gram is usually the reference unit used. Depending on what the particular topic is, and especially its scale, an appropriate prefix will be appended to the gram unit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For instance, when the target is &lt;a href=&quot;http://www.nature.com/nature/journal/v447/n7146/abs/nature05847.html&quot; rel=&quot;nofollow&quot;&gt;hemispheric or global&lt;/a&gt;, petagrams (Pg) is often used to discuss carbon exchanges between large reservoirs. Therefore when discussing about a smaller unit (as in your case, a single forest), it seem to be appropriate to scale down the unit to megagrams (Mg). &lt;a href=&quot;http://www.bipm.org/en/measurement-units/prefixes.html&quot; rel=&quot;nofollow&quot;&gt;Here is the current reference table displaying common prefixes for SI units.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2015-11-03T18:59:54.363" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6843" PostTypeId="1" CreationDate="2015-11-04T05:59:50.280" Score="14" ViewCount="11499" Body="&lt;p&gt;If I'm standing at a lat of 30.000$^\circ$ and a long of 30.000$^\circ$ and I move to a lat of 30.001$^\circ$ and a long 30.000$^\circ$, how far have I gone? Is there a relationship between decimal places and lat and long distances?&lt;/p&gt;&#xA;" OwnerUserId="4744" LastEditorUserId="28050" LastEditDate="2015-11-05T15:25:56.277" LastActivityDate="2022-06-18T06:13:37.793" Title="How much distance does $0.001^\circ$ in latitude or longitude represent?" Tags="|measurements|geography|cartography|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6844" PostTypeId="2" ParentId="6843" CreationDate="2015-11-04T06:16:21.170" Score="9" Body="&lt;p&gt;Latitudes are &amp;quot;parallels&amp;quot; while longitudes are &amp;quot;meridians&amp;quot; that all meet at the poles.  For latitude, there is a set distance traveled per degree latitude no matter where you are on a spherical globe.  For longitude, it depends what latitude you are at.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BBmMe.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BBmMe.gif&quot; alt=&quot;Lines of Latitude and Longitude&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;sub&gt;(source: &lt;a href=&quot;https://www.learner.org/jnorth/images/graphics/mclass/Lat_Long.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;learner.org&lt;/a&gt;)&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;.......................... &lt;img src=&quot;https://i.stack.imgur.com/Ms2xq.gif&quot; alt=&quot;Latitude&quot; /&gt; .............. &lt;a href=&quot;https://i.stack.imgur.com/e2uRI.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/e2uRI.gif&quot; alt=&quot;Longitude&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Image source: &lt;a href=&quot;https://www.learner.org/jnorth/tm/LongitudeIntro.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.learner.org/jnorth/tm/LongitudeIntro.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Image Credit: Illinois State University&lt;/p&gt;&#xA;&lt;p&gt;Here is a nice calculator for you online:&#xA;&lt;a href=&quot;http://www.stevemorse.org/nearest/distance.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.stevemorse.org/nearest/distance.php&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;1 degree of latitude in physical distance is    68.94   statute miles or    59.91   nautical miles (110.95 km) -- for a spherical earth assumption.  So, a change of 0.001 degrees latitude is  0.06894 statute miles or    0.05991 nautical miles.  Though, an ellipsoidal earth approximation does have small variance in latitudinal distances.  Incidentally, longitude has the same distance between each degree &lt;em&gt;if you are at the equator&lt;/em&gt;.  At the poles, the distance between lines of longitude is zero.  Note that all distances are &amp;quot;as the crow flies&amp;quot; which means the terrain is disregarded in the distance calculation.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="2958" LastEditDate="2020-12-21T22:18:23.150" LastActivityDate="2020-12-21T22:18:23.150" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="6845" PostTypeId="2" ParentId="6839" CreationDate="2015-11-04T06:58:30.580" Score="9" Body="&lt;p&gt;&lt;strong&gt;Mg C is a tonne of Carbon.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An Mg - a megagramme - is a tonne. It's a silly way of writing a tonne for a general readership, but it's the strict SI equivalent of a tonne. So an &quot;Mg C&quot; is a tonne of Carbon - the standard unit when it comes to talking about pricing Carbon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Normally you wouldn't see anyone writing about a million Mg of anything; (in this case, of carbon). You'd either write about a Teragramme, or a million tonnes, but not a million Mg.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, if you draft a paper referring to millions of tonnes, and then the editor or a peer reviewer comes back and says that the tonne is not a strict SI unit but the Mg is, then someone in the chain of authors and editors may just do a search and replace on all the &quot;tonnes&quot; to replace them with &quot;Mg&quot;. And that's one way that you might end up with lots of references to &quot;million Mg C&quot;, instead of the more usual &quot;million tonnes of carbon&quot;&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="100" LastEditDate="2015-11-04T14:53:05.060" LastActivityDate="2015-11-04T14:53:05.060" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6846" PostTypeId="2" ParentId="6843" CreationDate="2015-11-04T07:27:33.450" Score="20" Body="&lt;p&gt;I don't understand the last sentence about decimal places, but I can tell you about the relationship between &lt;em&gt;lat&lt;/em&gt;, &lt;em&gt;long&lt;/em&gt; and distance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Over two centuries ago, &lt;a href=&quot;http://en.wikipedia.org/wiki/Metre#Meridional&quot;&gt;the meter was defined as one ten-millionth (1/10 000 000) of the length of a quadrant along the Earth's meridian; that is, the distance from the Equator to the North Pole&lt;/a&gt;. So, for &lt;em&gt;latitude&lt;/em&gt; the number of degrees from the pole to the equator is $90^\circ\!$, and the number of meters is 10 million (or 10,000 kilometers). That means $1^\circ\!$ of &lt;em&gt;latitude&lt;/em&gt; is $10,000/90 = 111$ kilometers, and $0.001^\circ = 0.111$ kilometers or $111$ meters, essentially an American football field plus both endzones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The total length of the Equator is about equal to four times the distance from a Pole to the Equator. (Slightly more because the Earth's figure is a little oblate, like a slightly flattened ball.) Think of a great circle going from the North pole, to the Equator, to the South pole, to the Equator on the opposite side of the world, then back to North Pole ($360^\circ\!\!$ of a circle). That would be (almost) equivalent to the great circle ($360^\circ\!\!$ of &lt;em&gt;longitude&lt;/em&gt;) of the Equator. So, at the Equator, $0.001^\circ\!$ of &lt;em&gt;longitude&lt;/em&gt; will also be $111$ meters. But...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other circles of &lt;em&gt;latitude&lt;/em&gt; are smaller than the great circle of the Equator, yet still have $360^\circ\!$, so those degrees cover less than $111$ kilometers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SRU4p.gif&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SRU4p.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact, the size of a degree of &lt;em&gt;longitude&lt;/em&gt; as a function of &lt;em&gt;latitude&lt;/em&gt; scales as the cosine of the &lt;em&gt;latitude&lt;/em&gt;. So $0.001^\circ\!$ of &lt;em&gt;longitude&lt;/em&gt; change at $30^\circ\!$ &lt;em&gt;latitude&lt;/em&gt; would be $111 \times \cos (30^\circ\!) = 111 \times 0.866 = 96$ meters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2ipxf.png&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2ipxf.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4487" LastEditorUserId="4487" LastEditDate="2015-11-04T19:01:31.507" LastActivityDate="2015-11-04T19:01:31.507" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6847" PostTypeId="1" AcceptedAnswerId="6848" CreationDate="2015-11-04T16:19:41.050" Score="5" ViewCount="327" Body="&lt;p&gt;Given how rapidly weed plants spread and grow, choking out all other plant life, how come after millions of years we haven't ended with forests full of thistle or pokeweed, as opposed to pines or oak trees?&lt;/p&gt;&#xA;" OwnerUserId="4747" LastEditorUserId="4487" LastEditDate="2015-11-05T07:02:05.443" LastActivityDate="2015-11-05T07:02:05.443" Title="Why haven't weeds overtaken the entire planet?" Tags="|earth-history|mass-extinction|geobiology|evolution|ecology|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="6848" PostTypeId="2" ParentId="6847" CreationDate="2015-11-04T20:25:41.270" Score="3" Body="&lt;p&gt;A weed is just a plant where &lt;strong&gt;&lt;em&gt;you&lt;/em&gt;&lt;/strong&gt; do not want it. Totally a matter of context. Tumbleweeds are non-native, introduced centuries ago. I assume you mean the invasive species of plants that have been spread by humans and are disrupting ecologies throughout most of the world&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Until recently, these plants we consider weeds were limited in their range to home environments simply by geographic barriers and surrounding unfriendly environments. And the natural consumers, parasites and competitors in the home environments had adjusted to these plants and kept them in check.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When non-native plants are introduced into a new environment by humans, most of them do not thrive, but occasionally a plant is wildly successful. Eventually the potential consumers, parasites and competitors in that new environment will adjust through evolution. But the tragedy is that many or most of the original species will be destroyed before that balance is restored in a new, way more simplified form. The landscape itself may be totally changed. Removal of a key original species can cause great change too: &lt;a href=&quot;http://voices.nationalgeographic.com/2014/02/16/this-will-shatter-your-view-of-apex-predators-how-wolves-change-rivers/&quot; rel=&quot;nofollow&quot;&gt;How Wolves Change Rivers&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not only will many ecologies be reduced to much simpler versions, even if they eventually conquer the invasive plant, those simplified ecologies will closely resemble each other, if their geography is similar, even if on the other side of the world. If humans were to totally stop transplanting invasive species (collapse of civilization?), diversity would return after millions of years. We know this from &lt;a href=&quot;http://en.wikipedia.org/wiki/Extinction_event#Effects_and_recovery&quot; rel=&quot;nofollow&quot;&gt;Extinction Events&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to answer you question, weeds before human intervention generally did not take over in their home environments because the potential weeds and their natural consumers, parasites and competitors all evolved together in a quasi-equilibrium. Now, however, most ecologies throughout the world are out of equilibrium because of environmental change and/or invasive species. This will inevitably lead to simplified, usually less robust, weedy ecologies throughout the world. That reduction in diversity might as well be considered a permanent situation compared to the timescale of civilization.&lt;/p&gt;&#xA;" OwnerUserId="4487" LastEditorUserId="4487" LastEditDate="2015-11-04T22:12:43.270" LastActivityDate="2015-11-04T22:12:43.270" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6850" PostTypeId="2" ParentId="6751" CreationDate="2015-11-05T09:54:45.163" Score="3" Body="&lt;p&gt;Here is another example: &lt;a href=&quot;http://www.eurekalert.org/pub_releases/2015-11/nsf-bia110315.php&quot; rel=&quot;nofollow&quot;&gt;Ceren (El Salvador) around A.D. 660&lt;/a&gt; (discovered in 1978).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;Ceren is believed to have been home to about 200 people. Researchers have excavated 12 buildings, including living quarters, storehouses, workshops, kitchens, religious buildings and a community sauna. There are dozens of unexcavated structures, and perhaps even another settlement or two under the Loma Caldera volcanic ash, which covers an area of roughly two square miles.&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;But&lt;/em&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;Thus far, no bodies have been found, an indication a precursor earthquake may have given residents a running start just before the eruption.&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So no humans (yet?) and no mention of animals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This references the article &lt;a href=&quot;http://saa.publisher.ingentaconnect.com/content/saa/laa/2015/00000026/00000003/art00004;jsessionid=2egwpqgv8pvjl.alice&quot; rel=&quot;nofollow&quot;&gt;The Sociopolitical Economy of an Ancient Maya Village: Cerén and its Sacbe&lt;/a&gt; in the Latin American Antiquity magazine of the Society for American Archaeology (SAA).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You need to have a subscription to read it:&lt;br /&gt;&#xA;&lt;em&gt;The full text article is not available for purchase.&lt;br /&gt;&#xA;The publisher only permits individual articles to be downloaded by subscribers.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="595" LastEditorUserId="595" LastEditDate="2015-11-05T10:05:54.657" LastActivityDate="2015-11-05T10:05:54.657" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6851" PostTypeId="1" AcceptedAnswerId="6852" CreationDate="2015-11-05T18:07:21.970" Score="4" ViewCount="639" Body="&lt;p&gt;In physics, the Born approximation allows us to separate the wave-function in terms of electronic and nuclear components.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is this concept relevant in seismic inversion? For example &lt;a href=&quot;http://gji.oxfordjournals.org/content/early/2014/04/29/gji.ggu112.short&quot; rel=&quot;nofollow&quot;&gt;in Colombi et al. (2014), Geophys. J. Int. (2014), doi 10.1093/gji/ggu112 &lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="594" LastEditorUserId="28050" LastEditDate="2015-11-05T19:24:21.913" LastActivityDate="2015-11-05T20:12:33.820" Title="Using the Born approximation in seismic inversion" Tags="|geophysics|inversion|seismic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6852" PostTypeId="2" ParentId="6851" CreationDate="2015-11-05T20:12:33.820" Score="5" Body="&lt;p&gt;The best reference on this is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;J.A. Hudson and J.R. Heritage, 1981, The use of the Born approximation in seismic scattering problems, Geophys. J. R. Astr. Soc., v.66, 221-240.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically, the Born approximation is a governing principle of the standard imaging condition that treats seismic wavefields from a single point scatterer. This is the justification for simplifying the full elastic wave equation into the scalar and vector potential wavefields and just working with the scalar wave equation for the purposes of building seismic images.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a very nice derivation of this in Aki &amp;amp; Richards (Quantitative Seismology, 1980).&lt;/p&gt;&#xA;" OwnerUserId="2557" LastActivityDate="2015-11-05T20:12:33.820" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6853" PostTypeId="2" ParentId="4969" CreationDate="2015-11-06T11:21:10.230" Score="0" Body="&lt;p&gt;Biological answer: The amount of $CO_2$ would be in the range $100-600$ $ppm$, like it is today. The carbon from the crust would be completely used to produce biomass; there will be more living creatures on Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The lower range of $100$ $ppm$ is defined by C4-plants; their ability to use $CO_2$ collapses at these levels. The upper range is practically only $400$ $ppm$, and it's defined by C3-plants: their ability to use $CO_2$ doubles if the amount rises from $300$ $ppm$ to $600$ $ppm$. As humans produce less than $10\%$ of the world's $CO_2$ it means that even with 5 times the growth, the total $CO_2$ production in the world would only be $150\%$, which the existing plants can absorb at approx $400$ $ppm$ $CO_2$ levels. It's more probable though, that the $CO_2$ level wouldn't arise at all, the existing plants just grows a bit quicker and vegetation would spread to deserts and plankton in the sea would grow more. These phenomena are already observed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://de.wikipedia.org/wiki/Photosynthese#Kohlenstoffdioxid&quot; rel=&quot;nofollow noreferrer&quot;&gt;I can only provide a Wiki link on German language.&lt;/a&gt; Look the picture &#xA;&lt;a href=&quot;https://i.stack.imgur.com/d7IWK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/d7IWK.png&quot; alt=&quot;Co2-absorbtion by plants&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;CO2-Aufnahme&quot; Pls note that 0.02% = 200 ppm etc &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;The comment of Gordon Stanger forces me to improve this answer.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The evolution of the plants was totally different 60 Million years ago. The plants have of course now built their systems to current levels. If you study &lt;a href=&quot;https://en.wikipedia.org/wiki/Bryophyte&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bryophyte&lt;/a&gt;, you will find that even $2000$ $ppm$ is not a problem for them; they will just grow like crazy. I've tested that personally, with pure $CO_2$. Unluckily most of the good material I know, is in Finnish language; &#xA;&lt;a href=&quot;https://fi.wikipedia.org/wiki/Suo&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mire cover 5% of earth. 80% untouched Mainly Canada and Siberia.&lt;/a&gt; They can easily absorb any amount of $CO_2$ you desire to feed in atmosphere. Nowadays the rate might average $4.8$ $t/ha/a$, with $400$ $million$ $ha$ total amount, this alone makes almost $20$ $000$ $Mt/year$. This is comparable for the World fossil energy consumption, which is $13$ $000$ million tonne of Oil Equivalent in year. To point the scales out, approx $60\%$ of fossil fuels are coal, and the rest is hydrogen, which result is water. So these mires can alone absorb the whole $CO_2$ production of mankind. Even if they would feedback as much by themselves. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This absorption rate varies already from $1$ $to$ $10$ $t/ha$, even though we have not even seen $400$ $ppm$ $CO_2$ values. Well, for a short period during spring such a levels occur. Pls go to Lappland, at that time an experience the crazy growth of nature. &lt;a href=&quot;https://fi.wikipedia.org/wiki/Rahkasammalet_(luokka)&quot; rel=&quot;nofollow noreferrer&quot;&gt;They even change their color,&lt;/a&gt; to use wider spectrum of sunlight to their usage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe 60 million years ago all the plants were yellow. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;The Comments of Dikran Marsupial answered here:&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Tell me, how long did it take those peat bogs to form?&lt;/strong&gt;&#xA;Here is told how in 1957 a peat bog was dug clean; in 2010 they measured over 0.5 m thickness; Approx 1 cm/ year. This means that a &lt;a href=&quot;http://www.gtk.fi/_system/print.html?from=/_system/PressReleases/news_0206.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;average thick Finnish peat bog, 1.41 m,&lt;/a&gt; could crow in 141 Years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Next calculate the rate of deposition required to soak up anthropogenic fossil fuel emissions at their current rate.&lt;/strong&gt; &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2639/how-many-trees-would-i-have-to-plant-to-solve-global-warming/2642#2642&quot;&gt;(source, your answer)&lt;/a&gt;&#xA;Current rate is $9200$ $Mt$, i.e. with just $1$ $t/ha$, The &lt;a href=&quot;https://fi.wikipedia.org/wiki/Suo#Suoalueiden_m.C3.A4.C3.A4r.C3.A4&quot; rel=&quot;nofollow noreferrer&quot;&gt;worlds mire's 400 Million ha&lt;/a&gt;; Absorb $400$ $Mt$, at $5$ $t/ha$, $2000$ $Mt$, and at $10$ $t/ha$ $4000$ $Mt$, i.e. 40%. This is from $3\%-5\%$ of the Earth's land surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;I think your answer has some mistake on you calculations. Your forest grows only $1.5$ $t/ha$&lt;/strong&gt;. The &lt;a href=&quot;http://www.puuproffa.fi/PuuProffa_2012/7/puun-kasvu/metsan-kasvu&quot; rel=&quot;nofollow noreferrer&quot;&gt;average forest growth in Finland&lt;/a&gt; is $8m^3$/ha /year. This is -again- approx $4.8$ $t/ha/year$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Claim: &lt;strong&gt;We would need to turn 42% of the Earths land surface into peat bogs&lt;/strong&gt; (or forests?) &#xA;I make this simple; &lt;a href=&quot;http://www.unep.org/Documents.Multilingual/Default.asp?DocumentID=523&amp;amp;ArticleID=5723&amp;amp;l=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;according to this link&lt;/a&gt;; Peat lands are &lt;em&gt;storing on average 10 times more carbon per hectare than other ecosystems. Peat lands occur in 180 countries and cover 400 million hectares or 3% of the world's surface.&lt;/em&gt; So if we have 3%, which counts for 30% of average forest, we only need 3% peat lands and 12% forest. &lt;a href=&quot;https://en.wikipedia.org/wiki/Forest&quot; rel=&quot;nofollow noreferrer&quot;&gt;But we have 30% forest!&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="3098" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-11-18T01:05:17.570" CommentCount="14" ContentLicense="CC BY-SA 3.0" />
  <row Id="6855" PostTypeId="1" CreationDate="2015-11-06T14:38:07.630" Score="2" ViewCount="274" Body="&lt;p&gt;There is a rock that I have been climbing ever since I was a kid to get a magnificent view of an escarpment. One of the things that was part of our rock tour among other things was a perfect human child foot impression on top of the rock. It looks like the rock was molten or wet and someone just stepped on it before it dried.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this even possible?&lt;/p&gt;&#xA;" OwnerUserId="4754" LastEditorUserId="28050" LastEditDate="2015-11-06T17:43:26.007" LastActivityDate="2015-11-10T02:44:28.367" Title="A human foot impression on a rock" Tags="|geology|rocks|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6858" PostTypeId="1" CreationDate="2015-11-07T06:52:59.483" Score="1" ViewCount="2602" Body="&lt;p&gt;According to reports and charts meteorological phenomenon El Niño is close to Iran, but the question is, El Niño phenomenon in Iran is likely to achieve? &#xA;What are the consequences?&lt;/p&gt;&#xA;" OwnerUserId="4758" LastActivityDate="2015-11-11T12:41:13.483" Title="El Nino in the Middle East" Tags="|meteorology|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6861" PostTypeId="2" ParentId="6858" CreationDate="2015-11-07T08:44:44.300" Score="1" Body="&lt;p&gt;Although the El Nino phenomenon is primarily a Pacific Ocean phenomenon, affecting circum-Pacific countries the most, it occurs on such an enormous scale that it has knock-on affects around the world. These are difficult to generalize, but a rough idea can be gleaned from the map of global El Nino effects in such pages as:&#xA;&lt;a href=&quot;http://www.circleofblue.org/waternews/2015/world/el-nino-droughts-take-toll-in-africa-asia-and-the-pacific/&quot; rel=&quot;nofollow&quot;&gt;http://www.circleofblue.org/waternews/2015/world/el-nino-droughts-take-toll-in-africa-asia-and-the-pacific/&lt;/a&gt; &#xA;Bear in mind that there are other co-variables of ocean and atmospheric circulation that operate upon time scales varying from years to decades. These can either amplify or negate the extra-Pacific El Nino effects. Therefore the specific effects for any given year require modelling with atmosphere-Ocean-coupled global climatic models. Also consider that the outputs from all AOGCMs don't all agree, so it is necessary to consider a consensus from several outputs before drawing firm conclusions. Yet another consideration is that computer simulations do not give equal weighting to different parameters. So, as far as Iran is concerned, the modelled El Nino effects are likely to be very reliable for temperature, but wildly unreliable for rainfall. If you are concerned about rainfall in Iran my advice is to run a correlation analysis between the two variables: historic El-Nino-Southern Oscillation (ENSO) signal index (available on internet), and historic rainfall. Try this for monthly, seasonal and/or annual data. If the correlation coefficient is high, say &gt;0.70, use this relationship to adjust the normal expected rainfall in Iran. Attach as much credence to this as to any forward projections from any AOGCM. Rainfall analysis is not what AOGCMs were designed for. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-11-07T08:44:44.300" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6862" PostTypeId="2" ParentId="6855" CreationDate="2015-11-07T08:59:50.490" Score="4" Body="&lt;p&gt;I agree with kwinkunks, one can't give a specific response without knowing the kind of rock, age of the rock, whether there are other depressions/imprints  of comparable size in the adjacent rock, etc. &#xA;In general, whilst there is a feint possibility of preservation of a human footprint in very young rocks, it is wildly improbable. Consider the surface area of exposed rocks on the Earth, and the trillions of impressions from differential weathering, a host of diagenetic processes, heterogeneous rock textures, etc. It would be very strange if, by chance alone, some of these depressions didn't resemble a child's footprint. But please try to give more details so can we can evaluate this inquiry. &#xA;Incidentally, this brings to mind some creationist 'arguments' for human and dinosaur footprints in the same strata. They have all been investigated, and all shown to be spurious. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-11-07T08:59:50.490" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6863" PostTypeId="2" ParentId="5282" CreationDate="2015-11-07T19:46:13.847" Score="-4" Body="&lt;p&gt;There doesn't seem much point in trying to 'de-acidify' something that is fact an alkali.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The pH of the sea has far more to do with its temperature then anything else, it's ability to hold $\ce{CO2}$ for example is dependent on this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Acidification of the oceans is a myth, it is if anything, becoming less Alkali, closer to neutral pH. &lt;/p&gt;&#xA;" OwnerUserId="4760" LastEditorUserId="4487" LastEditDate="2015-11-07T22:42:14.837" LastActivityDate="2015-11-07T22:42:14.837" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="6864" PostTypeId="1" CreationDate="2015-11-07T23:08:25.667" Score="5" ViewCount="476" Body="&lt;p&gt;This summer has seen very low sea surface temperature anomalies in the North Atlantic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using animations of these over the last year I feel the runoff of freshwater from Hudson Bay, into the Labrador current, and in turn into the Gulf Stream component of the AMOC, has been a cause of the disruption of heat transfer to the North Atlantic Drift.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would this be correct? Has the runoff into Hudson Bay increased since September last year compared to a 10 year average?&lt;/p&gt;&#xA;" OwnerUserId="4760" LastEditorUserId="4487" LastEditDate="2015-11-08T06:53:12.713" LastActivityDate="2015-11-08T06:53:12.713" Title="Does the Labrador current affect North Atlantic climate?" Tags="|oceanography|ocean-currents|climate-models|arctic|ocean-models|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6865" PostTypeId="2" ParentId="5282" CreationDate="2015-11-08T00:20:58.583" Score="3" Body="&lt;p&gt;Yes, there is much more than enough limestone, by several orders of magnitude, to neutralize the acidity that we are creating - so much so that I am not even going to bother with the back of an envelope calculation. Given enough time (many millennia and possibly several million years) this will happen naturally. However,the process of re-equilibration with the introduced CO2 is sluggish because of both the reaction kinetics and, more particularly the deep ocean water mixing time. The current rate of CO2 emissions far exceeds both the rate of neutralization and the rate with which we could seed the oceans with CaCO3. Consider that, for limestone neutralization to succeed we would have to micronize entire hills and mountain ranges of limestone, and then distribute it, reasonably uniformly, over the world's oceans. Technically do-able, perhaps, but mind-bogglingly expensive and probably politically divisive. For many reasons it would be cheaper, easier and more ecologically appropriate to convert to renewable energy ASAP. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The above comment that the ocean's pH is temperature-controlled is wrong. There &lt;em&gt;is&lt;/em&gt; a temperature effect upon pH - see for example &lt;a href=&quot;http://www.aslo.org/lo/toc/vol_14/issue_5/0679.pdf&quot; rel=&quot;nofollow&quot;&gt;http://www.aslo.org/lo/toc/vol_14/issue_5/0679.pdf&lt;/a&gt; . However, this is insufficient to counter the oceanic acidification. Already the pH has decreased by between 0.06 and 0.10, with a global average decrease of about 0.075 (to 1990). See &lt;a href=&quot;https://en.wikipedia.org/wiki/Ocean_acidification&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Ocean_acidification&lt;/a&gt;. The last two decades have seen an acceleration of this trend. By century end most models project a mean pH decrease from 8.2 to 7.8 in the upper few hundred metres of ocean, where biological productivity is greatest. This is faster than at any time in the last 300 million years. To be effective, any neutralization with limestone would have to be achieved within a few decades, at a rate of neutralizing about 100 ppm CO2 over the entire ocean surface, and to a depth of several hundred metres.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2015-11-08T06:34:55.410" LastActivityDate="2015-11-08T06:34:55.410" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6866" PostTypeId="1" AcceptedAnswerId="6867" CreationDate="2015-11-08T02:33:31.570" Score="4" ViewCount="88" Body="&lt;p&gt;I live in a sub-tropical region of Australia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earlier today, we experienced temperatures of 31C and it was clear about 2 hours before I went out and noticed the following clouds directly above my house - the entire sky either has this or is very grey.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a constant background of thunder and distant lightning is observed - the wind is picking up a bit, though still a breeze. No rain at this stage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XVmrJ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XVmrJ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user4727" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T09:14:54.037" LastActivityDate="2019-08-29T09:14:54.037" Title="What type of cloud is this?" Tags="|meteorology|clouds|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6867" PostTypeId="2" ParentId="6866" CreationDate="2015-11-08T02:41:59.017" Score="3" Body="&lt;p&gt;These are &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Mammatus_cloud&quot; rel=&quot;nofollow&quot;&gt;mammatus&lt;/a&gt; clouds. The signify instability (via negative buoyancy, convective mixing, entrainment or other sources) at the cloud base which causes the bulbous udder-like structure. As in your case they can often be observed in association with strong convection. &lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2015-11-08T03:08:46.413" LastActivityDate="2015-11-08T03:08:46.413" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6869" PostTypeId="2" ParentId="6855" CreationDate="2015-11-08T09:04:15.223" Score="6" Body="&lt;p&gt;As @kwinkunks and @Gordon Stanger say, it's not possible to comment usefully on your particular observation without at least a picture and further information about the site. However, if you're asking “Is this even possible?” as a general question, the answer's yes, but under special circumstances. As an example, picture a scene in ancient East Africa: some individuals made their way across a layer of volcanic ash on the ground, leaving footprints in the process. Whether the ash was already wet or later rainfall fell on a dry ash layer (light enough not to destroy the evidence), the wet ash hardened and the footprints were buried under more ash fall - the “Laetoli” footprint tracks, discovered in Tanzania in the 1970s by Mary Leakey and her team, are remarkable evidence of bipedalism in our ancestors of ~3.7 million years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Laetoli&quot;&gt;https://en.wikipedia.org/wiki/Laetoli&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencedaily.com/releases/2011/07/110719194356.htm&quot;&gt;http://www.sciencedaily.com/releases/2011/07/110719194356.htm&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4658" LastEditorUserId="4658" LastEditDate="2015-11-08T09:35:32.990" LastActivityDate="2015-11-08T09:35:32.990" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6870" PostTypeId="2" ParentId="25" CreationDate="2015-11-08T12:21:34.030" Score="0" Body="&lt;p&gt;Solar uv is an extremely effective means of heating a body of water, the atmospheric temperature in comparison is ineffective.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Water has a high heat capacity, as uv Penetrates deeper into the water it's acts on a greater volume and transfers a lot of energy. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ARGO drifting bouy programme has data accessible to the public which gives us data down to 2000m pretty much worldwide. This is a great resource! But in terms of deep ocean I think we are pretty much in the dark.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thermohaline circulation is indeed a major route for surface water to overturn to the depths. Ssta and argo will give a good idea of what is heading down there.&lt;/p&gt;&#xA;" OwnerUserId="4760" LastEditorUserId="4760" LastEditDate="2015-11-08T12:52:54.633" LastActivityDate="2015-11-08T12:52:54.633" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6871" PostTypeId="2" ParentId="4612" CreationDate="2015-11-08T12:56:24.857" Score="5" Body="&lt;p&gt;The timing of events in the lithosphere is not necesarily as large as tens to hundreds of millions of years (10s-100s My), and much shorter time scales also apply.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Few examples, from short to long time scales: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Several thousands of years (ky) is all that took to reflood the whole Mediterranean Sea, after tectonic opening of the Gibraltar stretch (I bet you know this one... XD &lt;a href=&quot;http://www.nature.com/nature/journal/v462/n7274/full/nature08555.html&quot; rel=&quot;nofollow&quot;&gt;García-Castellanos et al, Nature 2009&lt;/a&gt;), ceasing a 100's-ky long period in which the Mediterranean was desiccated, also due to tectonics. One can think that these are just two events in one place, but considering that we get to know about it because is recent(!) [~5 Mya], and occured in an area where research efforts are way larger than in most other areas of the globe, it's easy to see that there are surely many other similar events in time and space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other example could be that of the tectonic uplift forces (mountain growth), which drive river drainage reorganization (drainage divide migration), and hence changing in enviroments and biocommunities in 10s ky scales (&lt;a href=&quot;https://www.sciencemag.org/content/343/6175/1248765.short?related-urls=yes&amp;amp;legid=sci;343/6175/1248765&quot; rel=&quot;nofollow&quot;&gt;Willett et al, Science 2015&lt;/a&gt;). Floral evolution change climate at meso- to regional scales. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The motion of the tectonic plates is slow (mm/yr) but changes in their motions happen relatively fast (10s ky), and this affects the dynamics of ocean and atmospheric circulation, hence climate. Opening/closing specific regions forces ocean water circulation changes, or albedo contrasts, both in turn changing the atmospheric dynamics.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another example could be the changes in atmospheric dynamics due to the growth of the Andes (&lt;a href=&quot;http://www.sciencemag.org/content/330/6006/927.abstract&quot; rel=&quot;nofollow&quot;&gt;Hoorn et al, Science 2010&lt;/a&gt;), or the changes in the Asian Monsoon dynamics (large intensification in My time-scales) due to growth of the Tibet (&lt;a href=&quot;http://sp.lyellcollection.org/content/342/1/1.full&quot; rel=&quot;nofollow&quot;&gt;Clift et al, GeoSocSpPubl 2010&lt;/a&gt;) [which didn't happened at ~10Ma, as said in one of the answers]. The growth of a mountain might be slow, but not so the time-frame in which the orogen passes the threshold of relevantly affecting atmospheric circulation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we go to larger time scales, subduction processes, one tectonic plate going under another, leads to the formation of volcanic chains, and hence increases in gas emissions, with well known climatic effects. An example would be the initiation of subduction in the W coast of S America, which created the volcanic chain in the Andes... Just think about all those new volcanos starting to go off around the same time periods.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lately, there are proposals that subducting oceanic (lithospheric) slabs, when passing down deeper than the 660km-depth boundary (not always the case), change the scale at which mantle convective circulation occurs, which in turn creates oceanic mid-ocean ridges, and eventually, new oceans. This is very much under debate, but I wanted to conclude with a very large time-scale event affecting climate...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are just few examples, which I find more representative and easy to visualise, but there are plenty more, such as glaciar-related ones mentioned in another answer. Now think about all these effects happening coevally in different parts of the globe, and you'll easily understand the (huge!) influence of the lithosphere component on climate at all time scales.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In any case, I think the right mind-set is that, although the processes are slow when comparing to climatic dynamics, they reach thresholds (in &quot;short&quot; periods of time) that completely change the Earth System, including climate.&lt;/p&gt;&#xA;" OwnerUserId="4765" LastEditorUserId="4765" LastEditDate="2016-02-20T22:23:30.080" LastActivityDate="2016-02-20T22:23:30.080" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6872" PostTypeId="2" ParentId="6858" CreationDate="2015-11-08T14:39:46.287" Score="2" Body="&lt;p&gt;A very quick and general answer, if anyone wants to get more specific, feel free:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the question is, El Niño phenomenon in Iran is likely to achieve? What&#xA;  are the consequences?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Iran's been through several El Nino's, so its not like this year you'll see things you've never seen before.   I mean, you could.  There's always a chance of record breaking weather, but have a look at El Nino's and how often they occur, &lt;a href=&quot;http://ggweather.com/enso/oni.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; and more numerical and monthly specifics &lt;a href=&quot;http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensoyears.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we assume this year will be a strong El Nino, then look back at weather in Iran in winter 97-98 through Summer 1998, and Winter 82-83 into 1983.  Those were the 2 most recent big El Ninos.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found this &lt;a href=&quot;http://www.tasnimnews.com/en/news/2015/10/20/894550/iran-braces-for-el-nino-hard-frost&quot; rel=&quot;nofollow noreferrer&quot;&gt;article&lt;/a&gt; from last month.  You probably have better access to local updates than I do, but it seems that frost and flooding are the primary concerns.    As Gordon Stranger points out, that's not a guarantee, only an increased chance that it happens.   &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;El Niño is close to Iran&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;El Nino is in the Pacific Ocean.   The El Nino effect is all over the globe, so it's, in a sense, close to everywhere on earth.  Here's a kind of cool picture of the effects of the 1982-83 El Nino.  Those were just the effects for that one year, and no two El Nino's will affect the globe in the same way, though they can have some similar patterns.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7gEvP.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7gEvP.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.marinebio.net/marinescience/02ocean/englobe.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;However, you should be afraid of the possible occurrence of El Niño in&#xA;  Iran?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;When I first read this, I thought you were suggesting that he be afraid, but reading it again, I think what you're asking is whether you should be afraid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;El Nino probably isn't something to be afraid of cause there's no guarantee the effects will be bad where you are.   It's silly to worry about a 30% increased chance of something happening - which is basically what this is.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you live in a flood prone area try to prepare for flood.  Have food and drinking water on hand, maybe sandbags to put in-front of your doorway - which might help for a smaller flood.  If you're a farmer, as much as possible, try to prepare for Frost.   Fear isn't helpful, but planning ahead for possible bad weather events is always a good idea.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2015-11-08T14:39:46.287" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6878" PostTypeId="1" CreationDate="2015-11-09T06:46:46.627" Score="4" ViewCount="1035" Body="&lt;p&gt;Looking up at say a cumulus cloud at a height of 2km which covers say 10 degrees of the visible sky, what is the easiest way to estimate its rough size at its base?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Simply put, how large is the arc of visible sky viewed from the surface?&lt;/p&gt;&#xA;" OwnerUserId="4771" LastEditorUserId="4771" LastEditDate="2015-11-10T14:35:08.653" LastActivityDate="2015-11-14T23:35:56.333" Title="How to estimate size of cloud formation" Tags="|clouds|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6880" PostTypeId="2" ParentId="6858" CreationDate="2015-11-09T09:04:11.163" Score="1" Body="&lt;p&gt;In addition to the other two answers this article &lt;a href=&quot;http://irj.iars.info/volumes/828005012015/pdf/82800501201501.pdf&quot; rel=&quot;nofollow&quot;&gt;Relation between Rainfall and El Nino in Iran&lt;/a&gt; evaluates the relation between quantum of rainfall in Iran during El Nino years. The study concludes that an increase of rainfall is seen across the Iranian plateau during El Nino years and a decrease of rainfall is seen across coastal areas. On the whole El Nino years are beneficial for Iran. The author does perform a correlation study using Pearson's method and conclude a meaningful relationship does exist at the 0.01 significance level. Considering Iran's geography and arid lands this would suggest a more careful management of water resources and ensure the rainfall is harvested through  watershed management. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following study confirms the above findings  &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/(SICI)1097-0088(200001)20:1%3C47::AID-JOC461%3E3.0.CO;2-P/abstract&quot; rel=&quot;nofollow&quot;&gt;On the relationship between ENSO and autumn rainfall in Iran &lt;/a&gt; and reports that El Nino episodes produce greater rainfall than La Nina episodes. The regions that benefited the most are the southern foothills of Alborz mountains, northwestern districts and central areas. Sources of moisture appear to be the Mediterranean Sea, Black Sea, Persian Gulf and the Red Sea. There is no evidence to suggest that the Pacific Ocean and Indian Ocean are sources of moisture. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition the following study &lt;a href=&quot;http://www.hindawi.com/journals/amete/2013/846397/&quot; rel=&quot;nofollow&quot;&gt;Effects of El Nino Southern Oscillation on the Discharge of Kor River in Iran&lt;/a&gt; conclude that efforts need to be directed at flood and drought predictability. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In average, El Nino caused increased discharge by 15% at Chamriz station and 20% at Dehkadeh-Sefid station. The time of maximum impact was found in the months of February and March of the El Nino year. It can be expected that the results obtained in the present study will help to understand the variations of river discharge due to El Nino which in turn will help water managers, dam operators, and policy makers in water resources planning and management as well as flood and drought forecasting and mitigation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In &lt;a href=&quot;http://www.jstor.org/stable/2562643&quot; rel=&quot;nofollow&quot;&gt;Synoptic Climatology of Precipitation in Iran &lt;/a&gt; authors conclude that upper level disturbances are responsible for over fifty percent of rainfall. &#xA;If it is indeed the case rainfall maxima during El Nino years are experienced in February and March in Iran then these maybe due to Western Disturbances &lt;a href=&quot;https://en.wikipedia.org/wiki/Western_Disturbance&quot; rel=&quot;nofollow&quot;&gt;Western Disturbances&lt;/a&gt;. These are basically upper level systems (500 hPa and above) and the following study describes the dynamics of  winter precipitation  episodes over Iran as well &lt;a href=&quot;http://metnet.imd.gov.in/mausamdocs/15742_F.pdf&quot; rel=&quot;nofollow&quot;&gt;Numerical study of western disturbances over western Himalayas using mesoscale model &lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a recent review of Winter Western Disturbances and their multi annual variations. &lt;a href=&quot;http://link.springer.com/article/10.1007%2Fs00382-014-2248-8&quot; rel=&quot;nofollow&quot;&gt;Multi-annual variations in winter westerly disturbance activity affecting the Himalaya&lt;/a&gt;. These authors confirm the same sources of moisture.&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2015-11-11T12:41:13.483" LastActivityDate="2015-11-11T12:41:13.483" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6881" PostTypeId="1" CreationDate="2015-11-09T09:29:19.213" Score="8" ViewCount="1434" Body="&lt;p&gt;Global weirding is a term used to describe how, with global warming, &lt;a href=&quot;http://www.nytimes.com/2010/02/17/opinion/17friedman.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;we will see more extreme weather events&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Avoid the term “global warming.” I prefer the term “global weirding,” because that is what actually happens as global temperatures rise and the climate changes. The weather gets weird. The hots are expected to get hotter, the wets wetter, the dries drier and the most violent storms more numerous.&lt;/p&gt;&#xA;&lt;p&gt;The fact that it has snowed like crazy in Washington — while it has rained at the Winter Olympics in Canada, while Australia is having a record 13-year drought — is right in line with what every major study on climate change predicts: The weather will get weird; some areas will get more precipitation than ever; others will become drier than ever.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I have a decent understanding of physics but don't know much about weather and climate. I think I understand a few things about global weirding:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Warmer waters mean typhoons can form more often, so in locations where extreme weather is also caused by typhoons they will see this more often&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Warmer air can transport more water and since steam pressure rises greater than linear with temperature, the same temp. swing around a high mean means that more water can precipitate.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;I often here a statement to the effect that more energy in a weather system means it has more extreme 'swings' in its behaviour. I find this rather opaque and unconvincing.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Here's what I don't understand: Does 'extreme heat wave' in this context mean&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;In 2100, we'll see more extreme heat events relative to 2015 mean temperatures &lt;em&gt;or&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;In 2100 we'll see more extreme heat events relative to 2100 mean temperatures&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I think it means the latter, but given that today's heat waves can cost lives and damage crops, I think it would be relevant to point out that we will see more of this so the first definition has some merit. So I want to be clear about the terminology.&lt;/p&gt;&#xA;&lt;p&gt;But my main question is, will we see more extreme temperature swings and what are the main mechanisms driving this?&lt;/p&gt;&#xA;" OwnerUserId="117" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-03-11T03:37:32.130" Title="What does global weirding mean regarding temperature extremes?" Tags="|climate-change|global-weirding|extreme-weather|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6882" PostTypeId="5" CreationDate="2015-11-09T09:31:15.227" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2015-11-09T09:31:15.227" LastActivityDate="2015-11-09T09:31:15.227" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6883" PostTypeId="4" CreationDate="2015-11-09T09:31:15.227" Score="0" Body="Global warming is said to lead to more extreme weather events, this is called global weirding" OwnerUserId="117" LastEditorUserId="117" LastEditDate="2015-11-09T10:00:00.703" LastActivityDate="2015-11-09T10:00:00.703" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6884" PostTypeId="5" CreationDate="2015-11-09T09:31:51.710" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2015-11-09T09:31:51.710" LastActivityDate="2015-11-09T09:31:51.710" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6885" PostTypeId="4" CreationDate="2015-11-09T09:31:51.710" Score="0" Body="A weather event that's significantly outside the norm for its time and place" OwnerUserId="117" LastEditorUserId="10831" LastEditDate="2018-07-20T09:07:22.867" LastActivityDate="2018-07-20T09:07:22.867" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="6889" PostTypeId="1" CreationDate="2015-11-10T01:14:21.967" Score="1" ViewCount="634" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/y2COW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/y2COW.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a particular type of rock specimen is found throughout Earth and is made entirely of natural minerals, but the individual specimens differ minutely from another in size and shape and look to be manufactured by intelligence, does science have to conclude it’s just a rock because the composition is entirely from earth minerals? Or is it because these specimens are also found on Mars? If only Earth had them, would science say that they are ancient artifacts from a past civilization?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are photos of &lt;a href=&quot;https://en.wikipedia.org/wiki/Navajo_Sandstone#Iron_oxide_concretions&quot; rel=&quot;nofollow noreferrer&quot;&gt;Moqui Marbles&lt;/a&gt; from Earth, and similar formations on Mars. I've held some that are hollow and some that were filled. They even have a negative pole effect on each other as though intended to keep a distance from the next one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1FmPy.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1FmPy.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3Nxet.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3Nxet.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CI1zr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CI1zr.jpg&quot; alt=&quot;Moqui-Marbles Utah&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4617" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T11:50:08.527" LastActivityDate="2019-08-29T11:50:08.527" Title="How are natural specimens, such as ‘Moqui Marbles’, distinguished from man-made artifacts?" Tags="|rocks|sedimentology|mars|diagenesis|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6890" PostTypeId="2" ParentId="6889" CreationDate="2015-11-10T02:42:22.460" Score="6" Body="&lt;p&gt;It's not completely clear what you're trying to ask here, but I'll have a go at it anyway.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If earth only had them would science say there are ancient artifacts from a past civilization?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The only way &quot;science&quot; would say there are ancient artifacts from a past civilisation is if there is evidence to support that. This is not some kind of default thing science resorts to when it cannot explain something. This is also something that UFOists like: you see a light in the sky and you can't explain it, so it has to be an alien spaceship. No - it only means that you do not know what it is. Beautifully summed up by this meme:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9NSRx.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9NSRx.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Back to topic.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Does science have to conclude its just a rock because the composition is entirely from earth minerals? Or is it because these specimens are found on mars also so science had to say there natural.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A common misconeption is that rocks on Earth are any different from rocks on Mars or the Moon. That's actually false - these planetary bodies are made, to a first approximation, from the same stuff Earth is made of. Basalt (and I'm being extremely &lt;em&gt;&lt;a href=&quot;http://www.oxforddictionaries.com/definition/english/sensu-lato&quot; rel=&quot;nofollow noreferrer&quot;&gt;sensu lato&lt;/a&gt;&lt;/em&gt; on this). There's nothing magical or mystical or alien about basalt. And you know what - because Earth is such a complex planet with tectonics and surface processes and everything there are much more interesting stuff on Earth then elsewhere (in my humble opinion).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If a specimen of rocks are found through out earth entirely of natural minerals but are different minutely from another in size and shape but look to be manufactured by intelligence.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Never underestimate the power of nature! Particularly when dealing with rocks and minerals. I know - I'm a scientist whose job is to make this stuff in a lab. Some natural rocks and minerals are extremely difficult to make.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How science identifies rocks?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It's also pretty easy to distinguish natural specimens from artificial ones. We scientists don't just look at rocks, we use a bunch of multi-million-dollar instrumentation to study them. When using those instruments distinguishing natural from artificial samples becomes as easy as distinguishing an elephant from a mouse.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-11-10T02:42:22.460" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="6891" PostTypeId="2" ParentId="6855" CreationDate="2015-11-10T02:44:28.367" Score="2" Body="&lt;p&gt;Foot impressions don't have to old. Just take a patch of ground made of clay or silt, pour some rain on it. Wait until dry and it's hard as a granite in some cases.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-11-10T02:44:28.367" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6893" PostTypeId="1" AcceptedAnswerId="6900" CreationDate="2015-11-10T07:09:42.153" Score="6" ViewCount="850" Body="&lt;p&gt;Was the first crust entirely mafic (oceanic) crust which was later distilled via volcanic arcs along subduction zones to make felsic rocks or did the earth start with bits of felsic crust?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are the ancient zircons most likely from felsic or mafic rocks?&lt;/p&gt;&#xA;" OwnerUserId="510" LastEditorUserId="725" LastEditDate="2015-11-11T03:10:35.810" LastActivityDate="2015-11-11T03:10:35.810" Title="What was the likely composition of Earth's early crust (how did crustal composition evolve)?" Tags="|geology|geochemistry|plate-tectonics|earth-history|crust|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6894" PostTypeId="2" ParentId="6708" CreationDate="2015-11-10T12:46:56.790" Score="0" Body="&lt;p&gt;Coal as a sedimentary rock:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Sedimentary rocks are formed from solid debris and dissolve minerals matter produced by mechanical and chemical breakdown of pre-existing rocks or in some cases from skeletal material of dead plants and animals.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;sub&gt;Source: &lt;a href=&quot;https://books.google.com/books?id=obsqBgAAQBAJ&amp;amp;pg=PT160&amp;amp;lpg=PT160&amp;amp;dq=Sedimentary%20rocks%20are%20formed%20from%20solid%20debris%20and%20dissolve%20minerals%20matter%20produced%20by%20mechanical%20and%20chemical%20breakdown%20of%20pre-existing%20rocks&amp;amp;source=bl&amp;amp;ots=f-2g4wt4y6&amp;amp;sig=tCiuD6tfddCMTeKemGKVvAcexdA&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0CCEQ6AEwAWoVChMI9ufij4eGyQIVTsBjCh2uOw8B#v=onepage&amp;amp;q=Sedimentary%20rocks%20are%20formed%20from%20solid%20debris%20and%20dissolve%20minerals%20matter%20produced%20by%20mechanical%20and%20chemical%20breakdown%20of%20pre-existing%20rocks&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;C.D. Gribble, 2012: &lt;em&gt;Rutley's Elements of Mineralogy.&lt;/em&gt; 27th ed. Springer Netherlands, 496pp&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The sediment in an organic sediment rock is made of fossils.&lt;/p&gt;&#xA;&lt;p&gt;Plants remain squashed deep underground over millions of years make an organic sedimentary rock called coal.Coal doesn't look like it is made of sediments.It is also often difficult to seee the plant fossils within it because they have become so compacted over time,the less stable materials have left and all that remains is carbon.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;sub&gt;Source: &lt;a href=&quot;https://answers.yahoo.com/question/index?qid=20091201222522AAFc6hi&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://answers.yahoo.com/question/index?qid=20091201222522AAFc6hi&lt;/a&gt; &lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;And coal is carbonaceous material.&lt;/p&gt;&#xA;" OwnerUserId="4773" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-11-10T14:33:33.513" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6896" PostTypeId="2" ParentId="6889" CreationDate="2015-11-10T17:51:43.587" Score="7" Body="&lt;p&gt;Like Michael, I find your question a little unclear, but the crux of it seems to be this:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... does science have to conclude [that a specimen is] just a rock because the composition is entirely from earth minerals?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The answer is an emphatic &lt;strong&gt;no&lt;/strong&gt;. There are lots of non-rocks out there, many of them manufactured by the (alleged) intelligence known as &lt;em&gt;Homo sapiens&lt;/em&gt;. There is certainly no rule in geology that you have to exclude this possibility from consideration when identifying a rock, no matter what its composition. After all, we’re perfectly capable of manufacturing artefacts from earth minerals. In fact, when identifying a specimen, you &lt;em&gt;have&lt;/em&gt; to consider the possibility that it's a product of intelligence: many enthusiastic amateurs have ended up collecting bits of brick, rubble, salt-lick, industrial slag and so forth by failing to do this :-).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One factor you mention in your question is the property&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;look to be manufactured by intelligence&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This, it turns out, is often a less useful diagnostic than you might expect. Lots of manufactured specimens don't look particularly manufactured, especially after a bit of erosion and weathering. Conversely, lots of naturally occurring objects look remarkably regular and intricate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WAdvM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WAdvM.jpg&quot; alt=&quot;slag and pyrite&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the left, objects manufactured by intelligence (&lt;a href=&quot;http://elementsunearthed.com/2013/06/03/tintic-soil-study-part-2-collection-trip-to-knight-smelter-and-silver-city/&quot; rel=&quot;nofollow noreferrer&quot;&gt;slag from the Knight Smelter in Utah&lt;/a&gt;). On the right, a naturally occurring specimen of &lt;a href=&quot;http://www.cfm-minerals.it/Italy_pages/Tuscany_ElbaIsland_Riomarina.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;dodecahedral pyrite from Elba, Italy&lt;/a&gt;. So a subjective, purely visual judgement that something ‘looks manufactured’ or ‘doesn't look manufactured’ can be very misleading.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your question also asks specifically about the ‘Moqui marbles’ of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Navajo_Sandstone&quot; rel=&quot;nofollow noreferrer&quot;&gt;Navajo Sandstone&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If Earth only had them would science say they are ancient artifacts from a past civilization?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The answer here is, again, a firm &lt;strong&gt;no&lt;/strong&gt;. This is easy to check because, of course, the ‘Moqui marbles’ had been observed long before Opportunity landed on Mars in 2004, and at that time scientists did not regard them as ancient artifacts from a past civilization. For example, &lt;a href=&quot;http://archive.li.suu.edu/docs/ms130/AR/chan3.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chan &lt;em&gt;et al.&lt;/em&gt; (2000)&lt;/a&gt; described them like this:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Small concretions of secondary iron oxide deposits are exclusively hematite-cemented sandstone. These concretions form all kinds of shapes from millimeters to centimeters in diameter, and cut across primary bedding structure. Some concretions are solid spherical balls around unknown nuclei; others are spherical rinds with plain red-stained, host rock interiors (lacking black-colored hematite cement on the inside). Concretions also exhibit forms that appear to have coalesced or joined (similar to two glued marbles), or exhibit a variety of other odd shapes (buttons, disks, irregular knobby forms to spiked-looking balls).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As you see, the authors identify these objects as &lt;em&gt;concretions&lt;/em&gt;. (Also note that, although you claim that they're only &quot;minutely&quot; different in size and shape, the description here mentions a great deal of variation in both those properties.) &lt;a href=&quot;https://en.wikipedia.org/wiki/Concretion&quot; rel=&quot;nofollow noreferrer&quot;&gt;Concretion&lt;/a&gt; is an extensively studied geological phenomenon which occurs across the globe. There’s no need to invoke an ‘intelligent manufacturer’ to explain it, whether or not concretions are found on other planets.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://archive.li.suu.edu/docs/ms130/AR/chan3.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chan, M. A., Parry, W. T., &amp;amp; Bowman, J. R. (2000). Diagenetic hematite and manganese oxides and fault-related fluid flow in Jurassic sandstones, southeastern Utah. &lt;em&gt;AAPG bulletin&lt;/em&gt;, 84(9), 1281-1310.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="4487" LastEditDate="2015-11-15T18:00:25.970" LastActivityDate="2015-11-15T18:00:25.970" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6897" PostTypeId="2" ParentId="361" CreationDate="2015-11-10T19:02:48.873" Score="2" Body="&lt;p&gt;Pont is correct. It is only the uppermost supracrustal rocks that seem brittle to us, and even then they are somewhat plastic when considered on a long enough timescale. Most of the crust is about 10 km thick (oceans) to &gt;40 km thick (continents), almost all of which is sufficiently hot and pressurized to be somewhat plastic. To give just one example of lateral compression caused by the non-spheroidal world, the Indian tectonic plate is rapidly moving north and crashing into the Tibetan plate (hence the Nepalese earthquake earlier this year). The Indian plate is being squeezed laterally, i.e. sub-parallel to lines of longitude, partly due to relative displacement of tectonic plates, and partly due to the geometric adjustment caused by the plate movement pole-wards from the tropics. That is, to a narrower Earth-radius geometry. The resulting deformation has caused a slight bulge over north India which has reversed the drainage of the Ganges over the past 25 million years or so. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I should point out that the geometry is not the only reason for the bulge - there is also the little matter of Himalayan compression, the two processes resulting in both north-south and east-west compression. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2015-11-10T19:07:49.163" LastActivityDate="2015-11-10T19:07:49.163" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6898" PostTypeId="2" ParentId="6893" CreationDate="2015-11-10T19:52:05.180" Score="2" Body="&lt;p&gt;Apart from a relatively thin veneer of sediments, today's crustal material is mainly granitic in nature, with a melting temperature of about 850 deg C. We don't know the early proto-Earth composition, but further to collision with the putative 'Theia' (see &lt;a href=&quot;https://en.wikipedia.org/wiki/Giant_impact_hypothesis&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Giant_impact_hypothesis&lt;/a&gt; ) the combination of thermal energy from the primordial gravitational accretion and kinetic energy of collision, would have raised the temperature to well in excess of the 2000 deg C melting point of ultramafics. The pre-fractionated precurser to the crust and mantle would have been somewhat alkaline, with water, K Al, Na etc all depressing the freezing point. Nevertheless the first crust to fractionate would have been at a temperature far above 850 deg C, and hence there were probably several cycles of fractionation, subduction and remelting of progressively more acidic (with respect to silica) crust before any recognizable 'Sialic' crust was able to stabilize. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One could therefore argue, purely on temperature grounds, that the first crust must have been mafic (boninite volcanics?), even leaning towards ultramafic, and since zircon is so refractory, one would expect the first zircons to have mafic associations, unlike the later granitic association.  &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-11-10T19:52:05.180" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6899" PostTypeId="2" ParentId="2158" CreationDate="2015-11-10T22:19:06.317" Score="4" Body="&lt;p&gt;An experienced Polynesian navigator would be the best person to answer this question but as a qualified ocean yacht master and having taught Coastguard courses including navigation, I believe there is some evidence to show that within the trade wind latitudes, where the winds are often steady and constant for extended periods of time; the refraction patterns in the waves which result from waves combining after passing islands, may be detectable beyond the horizon.  How far that is depends on the height of eye of the navigator and the height of the island. (the horizon at sea level in a typical Polynesian canoe would be around 4 Nm.) &#xA;The width of the island as well as the wavelength of the refracting waves would also affect how far the refraction pattern travels or extends beyond the island.  However, I believe Polynesian navigators may well have observed the wave motion and steered their vessels in the direction of the &quot;calm&quot; or flatter wave areas, thereby leading towards a not too distant island. But in my experience, observation of wave motion or direction is very difficult to view from the deck of a small vessel, so I do not believe it is a method that would be useful or possible beyond even as far as 50Nm from even a large islands such as New Zealand.  Besides which, the Polynesian catamarans, are not able to sail close to the wind so following a windward course would require a lot of tacking, to and fro in order to stay in sight of the calmer sea pattern.&lt;/p&gt;&#xA;" OwnerUserId="4777" LastEditorUserId="4777" LastEditDate="2015-11-10T22:31:19.993" LastActivityDate="2015-11-10T22:31:19.993" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6900" PostTypeId="2" ParentId="6893" CreationDate="2015-11-11T03:10:08.873" Score="3" Body="&lt;p&gt;Gordon's answer is correct to a first order approximation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the zircons that were found in Jack Hills are from the Hadean, more than 4 billion years ago. The fact that zircons that old exist is interesting - zircon is not a mineral you find in mafic rocks. Zirconium is an incompatible element in the mantle, so to get enough of it to form its own mineral you need some partial melting events. This may also be of interest:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/2950/725&quot;&gt;What are the high field strength and large ion lithophile (HFS or HFSE &amp;amp; LIL or LILE) elements?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you melt the mantle, you end up having basalt or more felsic rocks. If you have enough zircon in mafic rocks, you form baddeleyite: ZrO&lt;sub&gt;2&lt;/sub&gt;. Zircon, ZrSiO&lt;sub&gt;4&lt;/sub&gt; will only form in more felsic rocks, where you have enough Si. This alone suggests that some parts of the early crust was somewhat more felsic than a basalt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's more to it: inclusions of quartz and oxygen isotope data indicate that not only the zircon was in a felsic rock, it has evidence to suggest liquid water and hydrothermal alteration.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This entire thing is heavily debated, because there's only so much you can tell from a few grains of zircon. However, the basics are there - some felsic rocks existed as far as the Hadean.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-11-11T03:10:08.873" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6901" PostTypeId="2" ParentId="2158" CreationDate="2015-11-11T04:21:05.180" Score="1" Body="&lt;p&gt;The polynesians used primitive star charts, which is OK for latitude, but tells one nothing about longitude. The latter is the age-old problem that faced sailors for centuries, if not millennia, and which cannot be resolved without sophisticated instrumentation. The Polynesians probably supplemented their navigation with other clues, such as bird migratory tracks, current temperatures and strengths, cloud frequency and, as Tony says, wave refraction features.  &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-11-11T04:21:05.180" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6904" PostTypeId="2" ParentId="6759" CreationDate="2015-11-11T09:38:34.803" Score="2" Body="&lt;p&gt;Based on Probabilistic Seismic Hazard Analysis the probability of an earthquake of magnitude $m$ occurring at the source is obtained with the Truncated Exponential Distribution can be given by &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$P(M &amp;gt; m) = \int_{m}^{m_{max}} \frac{\beta e^{-\beta (m - m_{min})}}{\left( 1 - e^{-\beta (m_{max} - m_{min})} \right)}dm$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where :&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$m$ is the magnitude; $m_{min}$ is the minimum magnitude of earthquakes in source; $m_{max}$ is the maximum magnitude of earthquakes in source; $P(M &amp;gt; m)$ is the probability of occurrence of an earthquake with magnitude $M$ larger than $m$; $\beta = b \ln(10)$; $b$ is the slope in the Gutenberg–Richter (G–R) magnitude–frequency relation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source : &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0029549311000756&quot; rel=&quot;nofollow&quot;&gt;Development of probabilistic seismic hazard analysis for international sites, challenges and guidelines&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additional Read : &lt;a href=&quot;https://en.wikipedia.org/wiki/Gutenberg%E2%80%93Richter_law&quot; rel=&quot;nofollow&quot;&gt;Gutenberg Richter Law - why exponential distribution was used &lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="594" LastEditorUserId="5293" LastEditDate="2016-04-11T07:57:25.233" LastActivityDate="2016-04-11T07:57:25.233" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6905" PostTypeId="2" ParentId="6830" CreationDate="2015-11-11T09:53:39.570" Score="1" Body="&lt;p&gt;One possible example could be the study of ice cores in Antarctica where scientists are trying to determine changes in concentrations of gases like carbon dioxide over a period of time . Such variations serve as indicators for other Climate related factors such as Temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aNJUt.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aNJUt.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This record was a key contribution to climate science. One, it revealed how past CO2 levels compared to past temperatures. And since the data was directly derived from air bubbles trapped beneath hundreds of feet of ice, it also provided us with an exact measure for past atmospheres.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly, and perhaps much more ominously, it showed us how very far beyond any climate comparable to that great span of time we’d already come.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;102 ppm higher than at any time in the last 800,000 years&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Humans have now pushed the CO2 boundary 102 parts per million higher than the context provided by the last 800,000 years. It’s kind of a big deal when you consider that a mere fluctuation of about 100 parts per million CO2 was enough, when combined with changes in orbital forcing, to set off feedbacks resulting in a 4 C temperature change globally (8 C change for the Antarctic environment) as ice age proceeded to interglacial and back.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;source : &lt;a href=&quot;http://robertscribbler.com/2014/04/11/world-co2-averages-touch-402-2-ppm-daily-values-in-early-april-102-ppm-higher-than-at-any-time-in-last-800000-years/&quot; rel=&quot;nofollow noreferrer&quot;&gt;World CO2 Averages Touch 402.2 PPM Daily Values &lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further read : &lt;a href=&quot;http://www.nature.com/ngeo/journal/v8/n5/full/ngeo2422.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Links between atmospheric carbon dioxide, the land carbon reservoir and climate over the past millennium&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="594" LastActivityDate="2015-11-11T09:53:39.570" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6906" PostTypeId="2" ParentId="6881" CreationDate="2015-11-11T11:05:57.403" Score="3" Body="&lt;p&gt;First things first.   Global &quot;Weirding&quot; is very difficult to quantify.  That doesn't mean it's not happening, but it's inexact.  The idea came from climate models, which produced a lot of unexpected variations as opposed to more smooth and consistent warming and weather patterns are so complicated that there's still a lot of unknowns in this area.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Warmer waters mean typhoons can form more often, so in locations where&#xA;  extreme weather is also caused by typhoons they will see this more&#xA;  often&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Typhoons/Hurricanes are formed not just by warm water but by warm air and wind direction.   If the wind is too strong, the hurricane doesn't form, it needs to build and as it builds, begin to spin.    That's a dummies explanation, more details &lt;a href=&quot;http://www.weatherquestions.com/What_causes_hurricanes.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Warmer water can make hurricanes grow larger (unclear if it makes the wind blow faster too, it might).  One of the fun little jokes made about global warming is that in the IPCC's 4th assessment report (4AR) they predicted fewer hurricanes and in the 5th (5AR) they predicted more, though both were stated with some uncertainty and in the 4AR they predicted fewer with a chance of larger so those predictions aren't nearly as contradictory as this cartoon writers tries to make it sound.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZYSTM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZYSTM.jpg&quot; alt=&quot;https://pbs.twimg.com/media/B2ev-UdIYAA7KAM.jpg:large&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I personally trust 5AR over 4AR cause it's had 7 more years of research behind it, but whatever ends up being true, predicting hurricanes is complicated.   Short article on the debate of cause of the apparent recent increase &lt;a href=&quot;http://environment.about.com/od/globalwarming/a/hurricanecauses.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Warmer air can transport more water and since steam pressure rises&#xA;  greater than linear with temperature, the same temp. swing around a&#xA;  high mean means that more water can precipitate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm not sure about stream pressure, though warmer air can hold significantly more water vapor, so that I agree with.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Every 1 ° warmer, the atmosphere can hold in saturation about 6% more water.   So warmer air can hold quite significantly more water and as a result, lead to larger rain storms, though it's not just air temperature, but temperature variation as the warm air rises, etc.   But more precipitation per storm is a very likely consequence of man made climate change.   &lt;a href=&quot;http://www.engineeringtoolbox.com/relative-humidity-air-d_687.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, while the Earth has warmed less than 1 ° C so far, most of the surface temperature over land has warmed over 1 ° C (1.53 ° C on average - see &lt;a href=&quot;https://www2.ucar.edu/climate/faq/how-much-has-global-temperature-risen-last-100-years&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;) and it's the rainfall over land that affects us.   This means that the atmosphere over the land can hold as much as 10% more water on average than it did at pre-climate change levels.   Now, the temperature increase is lower in the upper atmosphere, so it's not really 10%.  but we've seen a few percent increase in how much water our atmosphere can store over land over just the last few decades and that's expected to continue to increase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Water evaporation and atmospheric water-vapor replenishment is trickier and depends on a few factors, river flow rate is based on rainfall and snow-melt upstream, wind speed and plant transpiration are also important.   Some people say CO&lt;sub&gt;2&lt;/sub&gt; is plant food but it's not that simple.  Plants need to take in oxygen to capture CO&lt;sub&gt;2&lt;/sub&gt; which they use to grow.   Sunlight and soil neutralists are the actually the &quot;food&quot; for plants, CO&lt;sub&gt;2&lt;/sub&gt; is what they use to grow and with higher levels of CO&lt;sub&gt;2&lt;/sub&gt; in the air, they need to take in less atmosphere to get what they need and as a result, they lose less water, so less water is returned to the atmosphere from forests and trees, as CO&lt;sub&gt;2&lt;/sub&gt; increases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, in a nutshell, the global warmed atmosphere on average can hold more water, it can also take more time for the atmosphere &quot;fill up again&quot; after a rainfall or after passing over high mountains and dropping a lot of water-vapor.  That's why you get more floods and more droughts.  That much is simple physics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If snow melt is high, that can lead to greater river flow and more flooding, and snow tends to fall in greater amounts with more water-vapor in the air.   There's a number of factors.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That strange 5 feet of snow event on Buffalo in 2014 happened when cold air blew over warm great lakes and the temperature difference caused the wind to draw a lot of water off the lakes.  Which, as it blew inland a mile or two, it quickly turned to snow and not the houses on the lake, but the houses a mile away from the lake got covered in snow.  The lake effect isn't unique to climate change.  It happened in the 1940s and 1970s, but warm lakes and a cold blast of air are the 2 drivers.  2014 was perfect for that with the polar vortex and the warm temperature colliding.  It was (I think) the largest lake effect Buffalo has on record.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cool video &lt;a href=&quot;https://www.youtube.com/watch?v=KA9XNRHxKbg&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I often hear a statement to the effect that more energy in a weather&#xA;  system means it has more extreme 'swings' in its behaviour. I find&#xA;  this rather opaque and unconvincing.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I think I agree with you here.  More &quot;energy&quot; is at best, vague, and it explains nothing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Water vapor condensation is one way that air temperature can rapidly change.   Condensation/cloud formation releases heat so more water vapor can play a role in faster temperature change, but I'm not sure how big a factor that is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Changes in ocean currents, perhaps caused by salinization changes and glacier melt can have significant effects.  Europe's moderate winters relative to high latitude are in large part caused by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Gulf_Stream&quot; rel=&quot;nofollow noreferrer&quot;&gt;gulf-stream&lt;/a&gt; and the gulf-stream may be slowing, article &lt;a href=&quot;http://www.independent.co.uk/environment/gulf-stream-is-slowing-down-faster-than-ever-scientists-say-10128700.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.  There's still some uncertainty on the extent of this effect, but there appears to be a connection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://www.slate.com/blogs/future_tense/2014/09/03/new_study_links_polar_vortex_to_climate_change.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Polar Vortex&lt;/a&gt; may also be growing as a result of climate change, based on some complicated models.   Despite the earth being warmer, harsh winters in some northern locations are still possible based on weather patterns.   Key point from article here:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;As strange as it sounds, Kim believes the intense cold air outbreaks&#xA;  in recent winters across Europe, Asia, and North America are, in his&#xA;  words, “a side effect of global warming.”&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;In 2100, we'll see more extreme heat events relative to 2015 mean&#xA;  temperatures or&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;In 2100 we'll see more extreme heat events relative to 2100 mean&#xA;  temperatures&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is a tough one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First point is that there really is no 2015 mean in terms of temperature.  We can generate a global average temperature for 2015, but local temperature fluctuates too much to have a 2015 standard.   Temperature variation vs a standard is generally measured against a baseline over a few decades.   For example, see chart below.  (I couldn't get it to embed), but it compares 2014 local temperature to a baseline of 30 years, 1981-2010.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ncdc.noaa.gov/sotc/service/global/map-blended-mntp/201401.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncdc.noaa.gov/sotc/service/global/map-blended-mntp/201401.gif&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If your question is rewritten as, will 2015, 2016, 2017, 2018, 2019, etc, compared to a 1981-2010 baseline have fewer extremes and look less &quot;weird&quot; than 2100, 2101, 2102, 2103, 2104, etc compared to a 2066-2095 baseline, then that's an interesting question but very hard to answer.   Individual years will be hit or miss, but on average, …hard to say.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As ice melt increases and as oceans continue to store heat and slowly grow warmer the weird weather variation could increase, but as CO&lt;sub&gt;2&lt;/sub&gt; levels begin to perhaps at some point, stop rising and reach a leveling off, we might see a decrease in &quot;weirdness&quot; compared to previous years, though the planet would still be warmer, but the rate of change might drop, so the best answer I can give you is that it could go either way.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The IPCC models suggest a gradual increase in the rate of warming for surface temperatures between now and 2100, as well as an expected increase in sea level rise but that corresponds to a steady increase in CO&lt;sub&gt;2&lt;/sub&gt;.  The future CO&lt;sub&gt;2&lt;/sub&gt; growth rate could be a factor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Guesses aside, when the experts say that weather will continue to get stranger, they are talking about compared to a consistent baseline, not a moving baseline cause that's a safer prediction, so your first sentence is the prediction that's usually put forth, but your 2nd sentence has a ballparkish 50% chance of being true too.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At some point the degree of weirdness has to level off simply because nothing builds indefinitely and for now global &quot;weirding&quot; appears to be gradually increasing, though as far as I know, precise measurements don't really exist.   It's too hard to quantify.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="725" LastEditDate="2017-03-11T03:37:32.130" LastActivityDate="2017-03-11T03:37:32.130" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6908" PostTypeId="2" ParentId="6881" CreationDate="2015-11-11T22:29:18.713" Score="-3" Body="&lt;p&gt;But it's very hard to compare a world where every 'weird' event gets rapidly broadcast to one even 20/30 years ago where communications were not as extensive and comprehensive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More water vapour increases albedo surely, therefore more tsi radiated back to space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If these weirding theories are correct, why have there been no cat 5 hurricanes landfall the eastern America's since Katrina? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;CO2 effects are inversely exponential and we've already 'eaten the worst bit' if you like&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you feel the oceans are warming, please cite the paper which supports thus aurgument.&lt;/p&gt;&#xA;" OwnerUserId="4760" LastActivityDate="2015-11-11T22:29:18.713" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6909" PostTypeId="2" ParentId="6820" CreationDate="2015-11-12T08:38:30.747" Score="4" Body="&lt;p&gt;Firstly, the RSS and UAH datasets do not &quot;line up nearly perfectly&quot;, the diagram below shows both products over the last 20 years (which appears to be what this question is actually about) here is the &lt;a href=&quot;http://woodfortrees.org/plot/rss/from:1995/plot/rss/from:1995/trend/plot/uah/from:1995/plot/uah/from:1995/trend/plot/none&quot; rel=&quot;nofollow noreferrer&quot;&gt;url&lt;/a&gt; used to generate it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7jKHM.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7jKHM.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, they disagree quite considerable on the value of the trend.  UAH and RSS are different methods used to infer trophospheric temperatures from them MSU instrument carried aboard various weather satellites.  The reason why they differ is because they use different methods to deal with the various drifts and biases involved in the measurements, and the fact that we don't know exactly how this is best performed is what is known as &lt;em&gt;structural uncertainty&lt;/em&gt;.  Note there are a couple of other similar products, but UAH and RSS are the main ones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to &quot;no significant warming for over 20 years&quot;, this is the subject of a fair bit of discussion in the journals, but not nearly as much as in the blogsphere, and a lot of it stems from not understanding what the term &quot;statistically significant&quot; means (and more importantly, what it doesn't mean).  The key point is that &quot;no significant warming&quot; does not mean &quot;there has been no warming&quot; or that &quot;the rate of warming has slowed&quot;.  Unfortunately the reasons for this are a little complicated, so I will start with a simple example.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider the usual statistical test for the bias of a coin, we start by stating the null and alternative hypotheses:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$H_0$ - null hypothesis, unbiased coin, probability of a head = p - 0.5.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$H_1$ - alternative hypothesis, biased coin, $p \neq 0.5$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We then flip the coin $n$ times and count the number of heads, if the p-value is less than some pre-determined value, typically $\alpha = 0.05$, then we say that we can &quot;reject the null hypothesis&quot;, implying that the data provides some support for our alternative hypothesis, $H_1$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, if we are unable to reject $H_0$, there are at least two reasons for this, it may be that $H_0$ is true, or it may be that $H_0$ is false but we haven't seen enough data yet to be confident of this.  For example, if we only toss the coin four times, then even if we get a head every time, we still won't be able to reject the null hypothesis as the p-value cannot be smaller than 0.0625.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Statistical_power&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;statistical power&lt;/em&gt;&lt;/a&gt; is the probability [in a frequentist sense] that the test correctly rejects the null hypothesis ($H_0$) when the alternative hypothesis ($H_1$) is true.  In this case, the statistical power of the test with only four flips is zero, because we can never reject $H_0$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, if you want to claim that it is in some way a surprise that we can't reject the null hypothesis, you need to show that the power of the test is high, and in the case of the trends over the last 20 years, it isn't particularly high, as similar trendless periods ocurr both in the observations and in the model output, as shown by &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2009GL037810/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;Easterling and Wehner&lt;/a&gt;.  For example the trend in RSS to 1997 is very similar to the trend from 1995 to the present day, and that is almost as long:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8oin3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8oin3.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Part of the reason for this is that the RSS and UAH datasets are both very sensitive to ENSO, and the trend over the last 20 years is dominated by the 1998 El-Nino.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So how long do you need to get reasonable statistical power?  Well climatologists generally use a period of at least thirty years (IIRC this is a WMO guideline).  &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2011JD016263/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;Santer el al&lt;/a&gt; performed a study and found that you would need &lt;strong&gt;at least&lt;/strong&gt; 17 years of data for identifying human impacts on surface temperatures.  Note this is a bare minimum, and refers to the detection of a trend in a randomly chosen time period.  If you wait until a period of 17 years comes a long before making the argument for a hiatus, the assumptions of that analysis are violated by the fact that multiple hypothesis tests are being implicitly performed, and in practice you would need a much longer period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now are scientists ignoring the apparent &quot;hiatus&quot;?  No, there have been many studies analysing it, for instance &lt;a href=&quot;http://iopscience.iop.org/article/10.1088/1748-9326/6/4/044022/meta&quot; rel=&quot;nofollow noreferrer&quot;&gt;Foster and Rahmstorf&lt;/a&gt; show that the apparent hiatus can be reasonably explained by ENSO and volcanic forcing, and so there is no real reason to suppose that there has been a pause in anthropogenic global warming, and the apparent hiatus is probably due to a redistribution of heat between the atmosphere and oceans.  There has even been a special issue of &lt;a href=&quot;http://www.nature.com/ngeo/journal/v7/n3/full/ngeo2116.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nature Geosciences&lt;/a&gt; devoted to this topic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;UPDATE: @user1286792 notes in the comments below: &lt;em&gt;&quot;!UAH, and !RSS show it has been 21.5 years since there has been any tropospheric warming.&quot;&lt;/em&gt;.  This clearly isn't true, at least for UAH.  If you plot the trend since 1995, it is essentially the same as the long term trend since the start of the dataset.  The fact that the RSS trend for the last 20 years is very different is I suspect the reason skeptic blogs switched from using UAH to RSS, but as always don't believe everything you read on line, and woodfortrees is a great tool for checking things.  As I said, UAH and RSS vary considerably over the last 20 years in their trends and the reason for this is structural uncertainty.  That doesn't mean that either of them are right or wrong and if your argument is not valid for both, then you probably shouldn't be confident that it is true.  Basically the timescale is too short to reliably estimate the trend given the uncertainties in the data, including the structural uncertainties.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Oyu6F.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Oyu6F.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Caveat: I think WFT may be using a previous version of UAH, however this rather illustrates my point about the structural uncertainties, if successive updates to the algorithm make such large differences to the trends, that means the structural uncertainties are very large and we should take that into account when looking at the trends.  However, the basic point remains that (i) the trends are too short to expect the warming to be significant (ii) the apparent haitus is adequately explained by ENSO and volcanic forcing (iii) similar periods of little warming are seen in the output of GCMs, and so it is not entirely unexpected.&lt;/p&gt;&#xA;" OwnerUserId="624" LastEditorUserId="624" LastEditDate="2015-11-13T08:28:44.760" LastActivityDate="2015-11-13T08:28:44.760" CommentCount="20" ContentLicense="CC BY-SA 3.0" />
  <row Id="6910" PostTypeId="1" AcceptedAnswerId="6915" CreationDate="2015-11-12T16:25:30.600" Score="7" ViewCount="1873" Body="&lt;p&gt;I want to understand the conditions under which &lt;a href=&quot;https://en.wikipedia.org/wiki/Hematite&quot;&gt;hematite&lt;/a&gt; $\ce{Fe_2O_3}$ and &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnetite&quot;&gt;magnetite&lt;/a&gt; $\ce{Fe_3O_4}$ form in nature. The linked Wikipedia articles explain various conditions under which they form, but does not really explain the difference between the two from a geological perspective, or state from a chemical basis why one should form rather than another.&lt;/p&gt;&#xA;" OwnerUserId="2491" LastEditorDisplayName="user20559" LastEditDate="2021-06-25T11:03:00.013" LastActivityDate="2021-06-25T11:03:00.013" Title="How do hematite and magnetite form?" Tags="|geology|geochemistry|mineralogy|minerals|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6911" PostTypeId="1" AcceptedAnswerId="6913" CreationDate="2015-11-12T17:12:27.563" Score="6" ViewCount="2355" Body="&lt;p&gt;If there was no water on the earth would there still be wind? If the planet was basically a desert from pole to pole, east to west, would the wind still blow? I understand that wind is a result of a difference in pressure, but is it true that water being naturally cooler is what creates that pressure difference?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't find any answers that clearly state whether or not wind would still exist without water and whether or not water is the originating source of wind. I see that most of the answers that talk about the source of wind say that cooler air moves in as warmer air rises, but wouldn't all the air in the world be warm/hot without water to cool it?  The pressure difference seems to be cool versus warm.  &lt;/p&gt;&#xA;" OwnerUserId="4787" LastEditorUserId="28050" LastEditDate="2015-11-12T17:19:04.983" LastActivityDate="2017-07-23T03:52:51.853" Title="Would there still be wind if Earth had no water?" Tags="|meteorology|wind|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="6912" PostTypeId="2" ParentId="6911" CreationDate="2015-11-12T18:01:05.540" Score="-2" Body="&lt;p&gt;If the world was uniform but still spinning, the difference between night and day would be enough to create a wind. Add mountains etc, plenty of temperature differences to create wind.&lt;/p&gt;&#xA;" OwnerUserId="4760" LastActivityDate="2015-11-12T18:01:05.540" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6913" PostTypeId="2" ParentId="6911" CreationDate="2015-11-12T20:30:24.337" Score="8" Body="&lt;p&gt;I wouldn't say water is naturally cooler than air.  What I would say is that water has a higher heat capacity than air.  This means it takes more energy to affect the same increase in temperature and conversely it takes water longer to cool down than air.  You can see this at night near bodies of water when the sea breeze changes to a land breeze as the land becomes cooler than the water - water temperatures tend to be stable across diurnal cycles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would also contest the statement that water cools the air.  Water does both heating and cooling.  When water evaporates into air, the air cools.  However take a look at any thunderstorm you see -- that is water causing heating as it condenses and freezes.  Water on the surface can also contribute to both heating and cooling.  During the day the cool water surface will have a heat flux that cools the air while at night the opposite may be true.  This depends on the air temperature and the SST. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now on to your question, &lt;strong&gt;yes&lt;/strong&gt;, there would still be wind if there were no water.  The energy that drives the wind is differential solar heating at the earths surface.  Variations in the surface topography and the shape of the earth mean that the solar flux isn't constant across the earth.  As long as we have a sun we will have surface pressure differences and wind.  Without water we would also see a stronger equator-to-pole temperature gradient (look at temperature variations right now on continents versus open ocean).  This would result in stronger winds that we see today.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-11-12T20:30:24.337" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6914" PostTypeId="1" AcceptedAnswerId="6917" CreationDate="2015-11-12T21:04:46.670" Score="4" ViewCount="87" Body="&lt;p&gt;Having read a little about &lt;a href=&quot;https://en.wikipedia.org/wiki/Sill_%28geology%29&quot; rel=&quot;nofollow&quot;&gt;sill&lt;/a&gt; formations like the &lt;a href=&quot;https://en.wikipedia.org/wiki/Palisades_Sill&quot; rel=&quot;nofollow&quot;&gt;Palisades Sill&lt;/a&gt; (eastern USA) and &lt;a href=&quot;https://en.wikipedia.org/wiki/Whin_Sill&quot; rel=&quot;nofollow&quot;&gt;Whin Sill&lt;/a&gt; (UK), I understand that strata became separated by the injected layer of magma, with monumental thicknesses achieved in the two examples mentioned.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, when one considers the weight of the overlying rock, especially if a sill has formed up to several kilometres below the surface, is it the case that the strata and rocks immediately beneath the growing, injected magma layer were &lt;em&gt;sinking&lt;/em&gt;, i.e. a descent of the lower solid layer(s) — with magma being injected from somewhere via fissures, etc., to form the sill above — until static equilibrium was achieved? Or did the pressure from the injected magma layer cause the overlying rocks — and therefore the ground surface — to be forced up?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there studies that have shown what occurs, for old sills or even ones that have been monitored whilst actively forming?&lt;/p&gt;&#xA;" OwnerUserId="4658" LastEditorUserId="28050" LastEditDate="2015-11-13T12:35:02.400" LastActivityDate="2015-11-13T12:36:52.410" Title="Do the rocks below an active sill go down, or those above go up, or both?" Tags="|volcanology|tectonics|magmatism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6915" PostTypeId="2" ParentId="6910" CreationDate="2015-11-13T05:21:13.953" Score="7" Body="&lt;p&gt;In nature, iron can be either metallic (&lt;span class=&quot;math-container&quot;&gt;$\ce{Fe^0}$&lt;/span&gt;), ferrous (&lt;span class=&quot;math-container&quot;&gt;$\ce{Fe^2+}$&lt;/span&gt;) or ferric (&lt;span class=&quot;math-container&quot;&gt;$\ce{Fe^3+}$&lt;/span&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In hematite, all of the iron is ferric: &lt;span class=&quot;math-container&quot;&gt;$\ce{Fe^3+_2O3}$&lt;/span&gt;. In magnetite, it is a combination of both ferric and ferrous: &lt;span class=&quot;math-container&quot;&gt;$\ce{Fe^2+Fe^3+_2O4}$&lt;/span&gt;. Thus, whether it is magnetite or hematite that are stable is mostly determined by the oxidation state of iron.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's look at an Eh-pH diagram:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Evazz.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Evazz.gif&quot; alt=&quot;Eh-pH stability diagram for iron oxides and hydroxides (Scheffer et al., 1989)&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; axis is the pH - the acidity of the system. Low pH means acidic, high pH means basic. The &lt;span class=&quot;math-container&quot;&gt;$y$&lt;/span&gt; axis is a measured by volts which may not be intuitive, but let's assume that higher values mean that there's more oxygen around and lower values mean that there's less oxygen around.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, the lower left area of the diagram is dominated by soluble ferrous iron (all the 2+ you see in there) whereas the top right is dominated by ferric iron. You may notice that there is no hematite here and magnetite only exists at the bottom right, but that's because this diagram is for water saturated ambient conditions. The important thing is where you get the ferric and ferrous iron.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Igneous, metamorphic and some sedimentary rocks have an oxygen fugacity (another measure of how much oxygen is around) that results in most of the iron being ferrous, and some being ferric. This is why in these rocks you end up having ferrous iron bearing minerals (olivine, amphiboles, pyroxenes, biotite) and some ferrous+ferric iron bearing minerals (such magnetite). Once you expose those minerals to the surface, where there's loads of oxygen around from the atmosphere, you oxidise the ferrous to ferric iron, and you get hematite instead. Basically, the rocks begin to rust.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, there are some processes where buried rocks can get highly oxidised, thus precipitating hematite, but that's not too common. It does happen though, and when it does it usually has something to do with groundwater (which are rather oxidised). Notice that according to the diagram, sometimes you don't need the system to be that much oxidised if it's basic enough (in terms of pH).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's also this open access paper that talks about conversion of magnetite to hematite:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Jing Zhao, Joël Brugger, Allan Pring, &lt;strong&gt;Mechanism and kinetics of hydrothermal replacement of magnetite by hematite&lt;/strong&gt;, Geoscience Frontiers, Volume 10, Issue 1, 2019, Pages 29-41,&#xA;&lt;a href=&quot;https://doi.org/10.1016/j.gsf.2018.05.015&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/j.gsf.2018.05.015&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2018-11-29T08:31:25.193" LastActivityDate="2018-11-29T08:31:25.193" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="6916" PostTypeId="1" CreationDate="2015-11-13T07:58:04.173" Score="11" ViewCount="1344" Body="&lt;p&gt;Given some location of interest $X$ in a lake or in the ocean with known lat and lon, I'd like to find the lat and lon of the coastal location that is closest to $X$, as well as distance between the two points. Of course, once the lat and lon of the coastal point is found, it's straightforward to compute the distance. I know of &lt;a href=&quot;http://oceancolor.gsfc.nasa.gov/DOCS/DistFromCoast/&quot; rel=&quot;noreferrer&quot;&gt;this &lt;em&gt;DistFromCoast&lt;/em&gt; dataset&lt;/a&gt; that has the distance to the nearest coastal point, but it does not provide the nearest coastal point itself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would anyone know of datasets, software, or algorithms that may help with my task?&lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorUserId="595" LastEditDate="2016-07-25T13:47:19.643" LastActivityDate="2016-11-14T09:24:11.333" Title="How can I find the nearest point on the coast from an ocean location?" Tags="|ocean|geography|open-data|coastal|software|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="6917" PostTypeId="2" ParentId="6914" CreationDate="2015-11-13T11:47:24.437" Score="2" Body="&lt;p&gt;It's both. The rocks above the sill go up, whereas those below it go down. For shallow diking events it's mostly up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is all based on theory of linear elasticity. People model deformation using elasticity all the time, especially for studying deformation at volcanoes which one can measure using GPS, leveling, InSAR, etc.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="28050" LastEditDate="2015-11-13T12:36:52.410" LastActivityDate="2015-11-13T12:36:52.410" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6918" PostTypeId="1" AcceptedAnswerId="6956" CreationDate="2015-11-13T19:58:22.547" Score="6" ViewCount="1104" Body="&lt;p&gt;I am getting stuck on the concepts of Total Catchment Area (TCA) and Specific Catchment Area (SCA) as I try to learn more about &lt;a href=&quot;http://csdms.colorado.edu/wiki/Model:TOPMODEL&quot; rel=&quot;noreferrer&quot;&gt;TOPMODEL&lt;/a&gt; and hydrology modeling. What do these metrics mean in hydrology? The context I encounter these in is in calculating Topographic Wetness Index (TWI) values. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My understanding so far is that: TCA is basically equivalent to a watershed for any given pour point; SCA helps determine saturation and saturation excess flow and it is the ratio of a local catchment area for a pour point divided by the width of the contour where that pour point is. I'm especially uncertain about SCA because it's unclear to me how the width of the contour is involved in a catchment area (based on my conceptual framework of a watershed a/k/a catchment area being defined by a single pour point). So, maybe I also need &quot;Flow Width&quot; (a term I think I've seen used to describe that contour width used in SCA) to be explained in order to understand SCA.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To give some context to what I'm referring to, here's a passage which references both TCA and SCA:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Upslope area is the &lt;em&gt;total catchment area&lt;/em&gt; above a point or length of contour and the &lt;em&gt;specific catchment area&lt;/em&gt; is the upslope area per width of contour or cell size, &lt;em&gt;L&lt;/em&gt; (Moore &lt;em&gt;et al.&lt;/em&gt;, 1991). &lt;em&gt;Specific catchment area&lt;/em&gt; is used to calculate saturation and saturation excess overland flow in hydrological models such as TOPMODEL (Beven and Kirkby, 1979) and, along with other topographic indices, to calculate erosion and landsliding in many other models. Upslope area is commonly used for mapping channels on the basis of threshold upslope areas for channel initiation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;J. Wainwright &amp;amp; M. Mulligan. &lt;em&gt;Environmental Modelling: Finding Simplicity in Complexity.&lt;/em&gt; Oxford: Wiley. 2012. &lt;a href=&quot;https://books.google.com/books?id=OMrYDQGprVwC&amp;amp;lpg=PT360&amp;amp;ots=WwUPHE9_0B&amp;amp;dq=What%20is%20the%20difference%20between%20Specific%20Catchment%20Area%20and%20Total%20Catchment%20Area%20in%20hydrology%3F&amp;amp;pg=PT360#v=onepage&amp;amp;q=What%20is%20the%20difference%20between%20Specific%20Catchment%20Area%20and%20Total%20Catchment%20Area%20in%20hydrology?&amp;amp;f=false&quot; rel=&quot;noreferrer&quot;&gt;Ebook&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;This was originally posted in GIS.SE where it was suggested it be moved here.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="4789" LastEditorUserId="28050" LastEditDate="2015-11-13T20:26:43.977" LastActivityDate="2015-11-19T15:52:31.600" Title="In hydrology, what's the difference between specific and total catchment area?" Tags="|models|hydrology|terminology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6919" PostTypeId="1" AcceptedAnswerId="6922" CreationDate="2015-11-13T20:29:04.997" Score="5" ViewCount="1211" Body="&lt;p&gt;Was there ever at any point in time a volcano in the great barrier reef? I thought atolls develop from volcanic islands, and the coral grow around them. &lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="28050" LastEditDate="2015-11-13T23:36:20.637" LastActivityDate="2015-11-14T11:49:37.537" Title="Volcanoes in the Great Barrier Reef" Tags="|geology|volcanology|carbonate|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6920" PostTypeId="1" AcceptedAnswerId="6921" CreationDate="2015-11-14T00:14:29.860" Score="21" ViewCount="28079" Body="&lt;p&gt;Many sources state that 12:00 noon is the high-point or mid-point of the sun's path across the sky.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, for where I am, this is obviously wrong. In my own town the high point of the sun occurs at about 13:30 in the summer (because of DST), and 12:30 in the winter, but clearly not 12:00 noon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why, at different longitudes, is the high-point of the sun not at 12:00?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you in advance. &lt;/p&gt;&#xA;" OwnerUserId="4791" LastEditorUserId="543" LastEditDate="2015-11-14T05:09:17.443" LastActivityDate="2017-01-01T23:50:19.283" Title="Why doesn't the sun reach its highest point overhead at exactly 12:00 noon?" Tags="|meteorology|seasons|" AnswerCount="6" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6921" PostTypeId="2" ParentId="6920" CreationDate="2015-11-14T01:48:52.533" Score="38" Body="&lt;p&gt;It's not a question of latitude but longitude and time zones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Prior to the advent of railway transportation the time set on clocks varied from towns within close proximity because the clocks were set to noon when the Sun was at its highest in the sky. This was more apparent for towns east and west of each other (ie different longitudes).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When railway transportation was developed there was a need to standardize times so that train timetables could be developed and arrival and departure times would be accurate and consistent&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This precipitated the development of time zones. Each time zone is approximately 15 degrees of longitude wide, but there are differences because of national/regional priorities. China which has a similar longitudinal extent as the contiguous states of the US has only one time zone, whereas there are four in the contiguous states of US.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Within a band of longitude the time is the same. In the time zones immediately east and west, the time is one hour more (east) and one hour less (west) - ignoring difference due to daily savings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason for time zone being approximately 15 degrees of longitude wide is the rate of spin of the Earth is 15 degrees/hour (360 degrees every 24 hours).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You state that in your town, noon is either 12:30 or 13:30, depending on daylight saving time. The reason for noon occurring at half past the hour is due to the boundaries of the time zone where you live. Where I live, noon is approximately at quarter past the hour.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-11-14T01:48:52.533" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6922" PostTypeId="2" ParentId="6919" CreationDate="2015-11-14T05:26:26.627" Score="5" Body="&lt;p&gt;Australia's Institute of Marine Science webpage &lt;a href=&quot;http://www.aims.gov.au/docs/projectnet/how-the-gbr-present-time.html&quot; rel=&quot;noreferrer&quot;&gt;How the Great Barrier Reef was formed&lt;/a&gt; is the result of the flooding of the former coastal plain when sea levels were lower.  A further explanation from the website states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The coastal plain included river valleys and small and large hills. Corals tended to grow best on hills because they were where waves broke and the water was most turbulent. Thus, although corals probably grew on any available hard shallow surface on the flooding coastal plain, reefs tended to form where there were hills.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A diagram of the formation is shown below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7uY5m.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7uY5m.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.booktoday.com.au/travel/great-barrier-reef-australia/&quot; rel=&quot;noreferrer&quot;&gt;Image source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, not the result of volcanoes, but rather the after effects of coastal plain inundation. &lt;/p&gt;&#xA;" OwnerDisplayName="user4727" LastActivityDate="2015-11-14T05:26:26.627" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6923" PostTypeId="2" ParentId="4600" CreationDate="2015-11-14T07:41:31.950" Score="-2" Body="&lt;p&gt;Water vapor certainly does absorb solar infrared radiation in the near infrared spectrum and mostly by water vapor - the graph shows this clearly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;GHG's heat the cool skin layer of the ocean - they cannot penetrate any more than a hairsbreadth so they simply promote evaporation and cooling via latent heating of the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://commons.wikimedia.org/wiki/File:Solar_Spectrum.png&quot; rel=&quot;nofollow&quot;&gt;http://commons.wikimedia.org/wiki/File:Solar_Spectrum.png&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4792" LastEditorUserId="106" LastEditDate="2015-11-14T16:22:05.580" LastActivityDate="2015-11-14T16:22:05.580" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6924" PostTypeId="2" ParentId="6920" CreationDate="2015-11-14T08:38:40.550" Score="30" Body="&lt;p&gt;Maybe a map will help visualise this a bit further:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IaWgC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IaWgC.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Source: &quot;Solar time vs standard time&quot; by Stefano Maggiolo - &lt;a href=&quot;http://blog.poormansmath.net/how-much-is-time-wrong-around-the-world/&quot; rel=&quot;nofollow noreferrer&quot;&gt;How much is time wrong around the world?&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, time zones are according to political boundaries, and this causes an offset from the official time to the solar time.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="6093" LastEditDate="2016-10-08T14:17:21.317" LastActivityDate="2016-10-08T14:17:21.317" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="6925" PostTypeId="1" AcceptedAnswerId="6927" CreationDate="2015-11-14T10:11:53.377" Score="2" ViewCount="116" Body="&lt;p&gt;Would anyone know of references (available online or not) that give detailed explanations and especially the physics behind violent meteorological events such as hurricanes?&lt;/p&gt;&#xA;" OwnerUserId="4650" LastEditorUserId="192" LastEditDate="2015-11-15T17:08:37.097" LastActivityDate="2015-11-15T17:08:37.097" Title="References on hurricanes" Tags="|meteorology|climate|tropical-cyclone|reference-request|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6926" PostTypeId="2" ParentId="6919" CreationDate="2015-11-14T11:49:37.537" Score="1" Body="&lt;p&gt;Coral reefs will grow on any suitable substrate given the basic requirements of sunlight, temperature (optimally 23 to 29 deg C), nutrient availability, and turbidity from waves or current flow.  In the deep ocean these conditions are almost invariably found on volcanic seamounts - hence your original perception. But as Ghost points out, there are no volcanoes in, near or under the Great Barrier Reef. In fact the nearest recent volcanism in Australia is in Western Victoria, nearly 2000 km from the GBR. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-11-14T11:49:37.537" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6927" PostTypeId="2" ParentId="6925" CreationDate="2015-11-14T11:58:49.937" Score="3" Body="&lt;p&gt;There are many generalized references, such as &#xA;&lt;a href=&quot;http://moe.met.fsu.edu/~rhart/papers-hart/2006Hart.pdf&quot; rel=&quot;nofollow&quot;&gt;http://moe.met.fsu.edu/~rhart/papers-hart/2006Hart.pdf&lt;/a&gt;&lt;br&gt;&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_cyclone&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Tropical_cyclone&lt;/a&gt;&lt;br&gt;&#xA;&lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/tcfaqD.html&quot; rel=&quot;nofollow&quot;&gt;http://www.aoml.noaa.gov/hrd/tcfaq/tcfaqD.html&lt;/a&gt;&lt;br&gt;&#xA;But I think the best is Kerry Emmanuel's presentation:&#xA;&lt;a href=&quot;http://www3.nd.edu/~its/Emanuel.pdf&quot; rel=&quot;nofollow&quot;&gt;http://www3.nd.edu/~its/Emanuel.pdf&lt;/a&gt;&lt;br&gt;&#xA;Is this sufficient detail for you? If not, then you probably need to do a course in tropical meteorology.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-11-14T11:58:49.937" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6929" PostTypeId="2" ParentId="6920" CreationDate="2015-11-14T14:11:48.680" Score="19" Body="&lt;p&gt;Time zones explain why you don't observe solar noon at 12:00 exactly, but not why the wall-clock time of solar noon varies with the seasons. In fact, even if you stay in place and don't observe DST, the time in the day where the sun is highest will vary throughout the year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fixed stars rotate around the celestial pole with a very constant speed (with extremely small and not completely predictable variations, less than milliseconds per day), so if you pick any fixed star and wait from &lt;em&gt;it&lt;/em&gt; is highest in the sky to it is highest in the sky again, it will take 23 hours, 56 minutes, 4.1 second, &lt;em&gt;each time&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Sun moves in the sky &lt;em&gt;more or less&lt;/em&gt; together with the fixed stars. It moves slowly &lt;em&gt;among&lt;/em&gt; the fixed stars, at a speed of around one degree of arc per day, such that after a year it has traced out an entire great circle on the celestial sphere. This means that the time between two true noons (the times on two consecutive days where the Sun is highest on the sky) is &lt;em&gt;on average&lt;/em&gt; about 4 minutes longer than the time between successive culminations of a fixed star.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, because the Earth's orbit around the Sun is slightly eccentric, the speed of the sun relative to the fixed stars is &lt;em&gt;not constant over the year&lt;/em&gt;. It moves quickest in early January and slowest in early July.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, the Sun doesn't move along the celestial equator -- it follows the &lt;em&gt;ecliptic&lt;/em&gt; which is inclined by 23 degrees, so at some times during the year it will &quot;waste&quot; different portions of its daily motion among the fixed stars on north-south movement that doesn't contribute to the four-minute lengthening of the true-noon interval. On the other hand, near the solstices the Sun is nearer to the poles, and it takes less than one degree of east-west motion along the ecliptic to lengthen the day by 1/360 of 24 hours.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The combination of these two effects means that the &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_time&quot;&gt;apparent solar day&lt;/a&gt; (the time interval between two true noons) varies during the year between 23 hours 59 minutes 40 seconds and 24 hours 0 minutes 30 seconds. The cumulative effect of this is known as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Equation_of_time&quot;&gt;equation of time&lt;/a&gt;, and can be as large as about half an hour -- that is, the time that passes between a true noon in early November and a true noon in early February will be about half an hour &lt;em&gt;more than&lt;/em&gt; a multiple of 24 hours.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The zone time we use for ordinary timekeeping is adjusted such that the &lt;em&gt;average&lt;/em&gt; difference over the year between true noon in Greenwich and 12:00 UTC is zero [*]. The &lt;em&gt;second&lt;/em&gt;, which is the basic scientific unit of time, was originally defined as $\frac1{24\times 60\times 60}$ of the length of a mean solar day, but has since been redefined using atomic clocks. Once every several years a &lt;em&gt;leap second&lt;/em&gt; is inserted into UTC to keep 12:00 UTC from drifting away from the averaged true noon time in Greenwich.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[*] Actually a slightly more complex process than simple averaging is used, which makes the outcome more precisely related to astronomical observables.&lt;/p&gt;&#xA;" OwnerUserId="4793" LastEditorUserId="4793" LastEditDate="2015-11-16T15:08:02.703" LastActivityDate="2015-11-16T15:08:02.703" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6930" PostTypeId="1" AcceptedAnswerId="6931" CreationDate="2015-11-14T15:56:05.277" Score="5" ViewCount="265" Body="&lt;p&gt;Reviewing market regulatory standards I came across the problem of finding a source that I could cite of concise, worldwide accepted industry geophysical terms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far I know Schlumberger Oilfield Glossary, SEG Wiki, SPE PetroWiki that give some information on some terms. In practice I need something like this definition in &lt;a href=&quot;http://wiki.seg.org/wiki/Dictionary:Crooked_line&quot; rel=&quot;nofollow&quot;&gt;SEG Wiki&lt;/a&gt; for seismic crooked lines. Although in this case I don't think the term is well defined. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am looking for a worldwide industry accepted glossary that I could rely on and cite. The broader it is the best will be for having less problems in future. Where would be the best place to find such source of information? Any other suggestions will be welcome.&lt;/p&gt;&#xA;" OwnerUserId="2680" LastEditorUserId="2680" LastEditDate="2015-11-16T22:43:47.560" LastActivityDate="2015-11-16T22:43:47.560" Title="Glossary of oil and gas industry geophysical terms" Tags="|geophysics|petroleum|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6931" PostTypeId="2" ParentId="6930" CreationDate="2015-11-14T19:20:22.673" Score="4" Body="&lt;p&gt;&lt;strong&gt;Sheriff's &lt;em&gt;Encyclopedic Dictionary&lt;/em&gt; is the closest thing to a canonical text, but the Schlumberger glossary is more up to date.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://wiki.seg.org/wiki/Dictionary:Sheriff&amp;#39;s_Dictionary&quot; rel=&quot;nofollow&quot;&gt;Sheriff&lt;/a&gt; is a scientific text, whereas the Schlumberger glossary is a little more generally accessible, but neither is comprehensive. Sheriff is especially poor on recent advances. On the plus side, you can edit it, if you're an SEG member.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;After those two, Wikipedia is probably your next best bet.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2015-11-14T19:20:22.673" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6932" PostTypeId="5" CreationDate="2015-11-14T21:49:47.743" Score="0" Body="&lt;p&gt;Tectonics is the application of field geology, petrology, geochemistry, geochronology, geophysics, remote-sensing, modeling and multidisciplinary studies to explains the evolution, structure, and deformation of Earths lithosphere.&lt;/p&gt;&#xA;" OwnerUserId="2680" LastEditorUserId="2680" LastEditDate="2015-11-15T04:30:13.610" LastActivityDate="2015-11-15T04:30:13.610" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6933" PostTypeId="4" CreationDate="2015-11-14T21:49:47.743" Score="0" Body="Tectonics is the application of field geology, petrology, geochemistry, geochronology, geophysics, remote-sensing, modeling and multidisciplinary studies to explains the evolution, structure, and deformation of Earths lithosphere." OwnerUserId="2680" LastEditorUserId="2680" LastEditDate="2015-11-15T23:29:02.727" LastActivityDate="2015-11-15T23:29:02.727" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6934" PostTypeId="2" ParentId="6878" CreationDate="2015-11-14T23:35:56.333" Score="1" Body="&lt;p&gt;Three methods spring to mind:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) If you can really estimate both the width in degrees and distance to the cloud, you can draw a triangle and use trigonometry to calculate the width. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) The distance to the cloud you may estiamte from the cloud type. But both height and width in degrees are uncertain numbers. Instead you can estimate cloud sizes by looking at planes passing through them. If you time how long it takes a plane to pass through a cloud, you can multiply that with its cruising speed to get the width of the cloud. The cruising speed (typically 500km/h) can be found via say, the Flightradar24 app.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) Using that app, you can also track the plane in real-time to map out not only the length of the cloud, but what land it is covering. No need to time the plane or know its speed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By following a plane on the app until it goes under the horizon at your location, you get a feel for &quot;how far away the horizon is&quot;, for clouds at that plane's altitude. high-altitude clouds and aurora at the horizon will be much farther away than low-altitude clouds. &lt;/p&gt;&#xA;" OwnerUserId="4796" LastActivityDate="2015-11-14T23:35:56.333" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6935" PostTypeId="1" CreationDate="2015-11-15T00:12:58.183" Score="2" ViewCount="86" Body="&lt;p&gt;I went to their site and read each of the topics in the &lt;a href=&quot;http://www2.epa.gov/learn-issues&quot; rel=&quot;nofollow&quot;&gt;&quot;Learn the Issues&quot;&lt;/a&gt; tab but, is there a list that the EPA deems to be the most important issues that need to be dealt with?&lt;/p&gt;&#xA;" OwnerUserId="4798" LastEditorUserId="4798" LastEditDate="2015-11-15T00:21:44.033" LastActivityDate="2015-11-15T21:53:22.957" Title="Does the EPA have a list of the nation's major environmental issues?" Tags="|environmental-protection|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6936" PostTypeId="2" ParentId="6920" CreationDate="2015-11-15T00:48:00.433" Score="-3" Body="&lt;p&gt;Well, Sun was there before people and any concept of time. &#xA;When people emerged, they naturally considered night as period when there is no Sun and Day where there was Sun on the sky. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When time was invented for the first time (ancient civilisations), most likely 12 was the time when the Sun was the highest on the sky. Then people became smarter and introduced different timezones in order to standardise the concept of time and this caused some deviations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then people thought they will be more productive (making more money) if there introduce the concept of Winter and Summer time what introduced further time deviations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore you do not see it anymore point 12.&lt;/p&gt;&#xA;" OwnerUserId="4801" LastActivityDate="2015-11-15T00:48:00.433" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6937" PostTypeId="1" CreationDate="2015-11-15T03:31:14.750" Score="1" ViewCount="82" Body="&lt;p&gt;What happens when the humidity is 100% in atmosphere. Does it heavily rains or fog formation occurs? Or is there any other possibilities?&lt;/p&gt;&#xA;" OwnerUserId="4802" LastActivityDate="2015-11-15T03:31:14.750" Title="What happens if humidity is 100%?" Tags="|meteorology|" AnswerCount="0" CommentCount="2" ClosedDate="2015-11-15T03:34:54.530" ContentLicense="CC BY-SA 3.0" />
  <row Id="6938" PostTypeId="1" CreationDate="2015-11-15T14:27:03.963" Score="3" ViewCount="128" Body="&lt;p&gt;Beyond the obvious fact that in many of the silicate subtypes they play an ionic 'glue' like role by bonding the tetrahedra units together; how do cations &lt;strong&gt;control&lt;/strong&gt; the structure of a silicate and how does it vary between different cations and silicates?&lt;/p&gt;&#xA;" OwnerUserId="4808" LastEditorUserId="94" LastEditDate="2015-11-15T18:04:19.033" LastActivityDate="2015-11-15T19:57:48.817" Title="How do cations control the crystal structure of silicate minerals?" Tags="|geology|mineralogy|crystallography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6939" PostTypeId="2" ParentId="6938" CreationDate="2015-11-15T19:57:48.817" Score="2" Body="&lt;p&gt;I would say that cations would control the structure in several ways; in the case of aluminum octahedra in aluminosilicates, for example, they might completely influence it by causing the presence of completely separate alternating layers of bonded octahedra. The octahedra may even dominate the unit-cell, appearing in a larger numerical and volumetric capacity than the tetrahedra.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, the different bonded cations have different polarities, and by extension, exert different forces on the relevant bonds; this plays a &lt;strong&gt;huge&lt;/strong&gt; role in determining how the structure responds under conditions of high pressure relevant to the Earth's interior, e.g determining where shearing takes place, etc.&lt;/p&gt;&#xA;" OwnerUserId="4810" LastActivityDate="2015-11-15T19:57:48.817" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6941" PostTypeId="2" ParentId="6935" CreationDate="2015-11-15T21:53:22.957" Score="2" Body="&lt;p&gt;The US EPA mandate is quite broad as are the range of environmental issues. The issues aren't really amenable to such a list because it is subjective to decide what is 'major' except in very broad terms. Major could mean greatest risk or it could mean of greatest importance to address soon. Those could be different things, for example, carbon dioxide emissions are high risk but difficult to address whereas an industrial site with leaky chemical drums might have only a local risk but need dealing with right away to contain the problem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The 'Learn the issues' tab gives the important areas in a general sense; you could look at the EPA organisation chart to see where they are putting their resources.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the specific case of pollution from old industries, The Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or Superfund) maintains the National Priorities List (NPL) for sites needing cleanup.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2015-11-15T21:53:22.957" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6942" PostTypeId="2" ParentId="6920" CreationDate="2015-11-16T08:32:12.617" Score="8" Body="&lt;p&gt;Henning Makholm's answer is excellent but omits the elegant definition of the &lt;em&gt;mean Sun&lt;/em&gt;, which is what the clock at the Prime Meridian attempts to match:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Consider a first fictitious Sun travelling along the &lt;em&gt;ecliptic&lt;/em&gt; with a constant speed and coinciding with the true sun at the perigee and apogee (when the Earth is in perihelion and aphelion, respectively). &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This removes the variation due to the orbit's eccentricity.  The orbit is symmetric about the line through perihelion and aphelion, so this makes the average offset zero.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Then consider a second fictitious Sun travelling along the &lt;em&gt;celestial equator&lt;/em&gt; at a constant speed and coinciding with the first fictitious Sun at the equinoxes. This second fictitious sun is the &lt;em&gt;mean Sun&lt;/em&gt;...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This second step removes the variation due to axial tilt; again, the matching-points are chosen for symmetry.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;J. Meeus (1998). Astronomical Algorithms. 2nd ed. Richmond VA: Willmann-Bell. p. 183.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="4819" LastActivityDate="2015-11-16T08:32:12.617" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6945" PostTypeId="1" AcceptedAnswerId="6946" CreationDate="2015-11-17T05:10:21.987" Score="21" ViewCount="9529" Body="&lt;p&gt;CO&lt;sub&gt;2&lt;/sub&gt; in the air dissolves into rain water, making them slightly acidic. Is that enough to deplete the surrounding air out of CO&lt;sub&gt;2&lt;/sub&gt;? If yes, how fast does this occur? Is it only with the first drops of rain or do you need several hours?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How long does it take for the surrounding atmosphere to regain its original CO&lt;sub&gt;2&lt;/sub&gt; contents, assuming this actually happens?&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2022-05-27T04:26:55.307" Title="Does rain (temporarily) deplete the surrounding atmosphere of carbon dioxide?" Tags="|meteorology|atmosphere|carbon|co2|rain|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6946" PostTypeId="2" ParentId="6945" CreationDate="2015-11-17T15:22:39.633" Score="16" Body="&lt;p&gt;Here is the mass-calculation. We will consider a column of the atmosphere with a footprint of 1m × 1m. This column weighs about 10,000 kg (per square metre). In these days of climate change we will assume the current average CO&lt;sub&gt;2&lt;/sub&gt; concentration is 400 ppm, yielding a total mass of CO&lt;sub&gt;2&lt;/sub&gt; in this column of 4 kg. &#xA;The rain doesn't wash out the entire thickness of atmosphere but only (in general) the lowermost troposphere. We will assume, generously, that some 2.5 kg of this 4 kg of CO&lt;sub&gt;2&lt;/sub&gt; is available to be scavenged by raindrops. &#xA;Now consider a cloudburst of raindrops, equivalent to some 100 mm  on the ground. So we have 0.1 cubic metres, or 100 kg, of fallen raindrops within our square metre column of air. The solubility of CO&lt;sub&gt;2&lt;/sub&gt; in air is strongly temperature dependent, up to 2.5 g per kg at 10 deg C. But at such a low temperature we couldn't achieve 100 mm of rainfall, so we will compromise at about 1.5 g per kg at 25 °C. So, assuming complete CO&lt;sub&gt;2&lt;/sub&gt; saturation within the raindrops (unlikely) our 100 kg of rain will contain 0.15 kg of CO&lt;sub&gt;2&lt;/sub&gt; , scavenged from about 2.5 kg of CO&lt;sub&gt;2&lt;/sub&gt; in the 'rained out' column of air, or about 6% of the low atmospheric CO&lt;sub&gt;2&lt;/sub&gt; . &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bear in mind that this assumes an enormous rainfall intensity, 100% CO&lt;sub&gt;2&lt;/sub&gt; saturation of the water and equilibrium chemical dynamics. After the raindrops hit the ground at least half of it will immediately re-evaporate back into the air, leaving, at absolute most, about 3% of the atmospheric CO2 leached out of the atmosphere that will be available to react with the soil, rock or biosphere. Also consider that this is but one of several important processes affecting CO&lt;sub&gt;2&lt;/sub&gt; transience, such as photosynthesis, respiration, volcanism, industrial pollution, etc. So the CO&lt;sub&gt;2&lt;/sub&gt; estimates that you read about are average values. Advection and turbulent air mixing should ensure that the CO&lt;sub&gt;2&lt;/sub&gt; regains approximately normal concentration within an hour or two after rainfall. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="725" LastEditDate="2016-09-14T10:48:26.757" LastActivityDate="2016-09-14T10:48:26.757" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="6947" PostTypeId="1" AcceptedAnswerId="6948" CreationDate="2015-11-18T01:52:21.553" Score="9" ViewCount="1482" Body="&lt;p&gt;I'm teaching a physics class, and I'm getting to the point where we are talking about the Coriolis effect.  I usually show a couple of photos/videos showing a storm in the Northern Hemisphere and a storm in the Southern Hemisphere, and talk about why they rotate different directions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it occurred to me that at some point in history, there could well have been two storms occurring in the same ocean but in different hemispheres.  Has this ever occurred?  This would most likely have to be in the Pacific or Indian Oceans (probably the Pacific, since from what I've gathered the Northern Indian Ocean is less active than most other cyclone basins.)  Ideally, a photo/video of this event would exist that I could show my students.&lt;/p&gt;&#xA;" OwnerUserId="4837" LastActivityDate="2019-02-23T05:42:53.577" Title="Have there ever been simultaneous cyclones in the same ocean but different hemispheres?" Tags="|meteorology|tropical-cyclone|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6948" PostTypeId="2" ParentId="6947" CreationDate="2015-11-18T02:22:44.280" Score="9" Body="&lt;p&gt;It does occasionally happen. Not often, because to kick-start a hurricane there has to be some rotation to start with, from the Coriolis effect, together with a sea surface temperature of &gt;27 &amp;deg;C (+ some other requirements such as lack of horizontal shear). This combination is best met during summer when one or other hemisphere is tilted towards the sun, so the hurricane seasons in both hemispheres tend to be 6 months out of synchronization. But there are occasional overlaps, as in this vector composite, found at &lt;a href=&quot;http://www.wunderground.com/blog/JeffMasters/archive.html?year=2015&amp;amp;month=06&amp;amp;MR=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.wunderground.com/blog/JeffMasters/archive.html?year=2015&amp;amp;month=06&amp;amp;MR=1&lt;/a&gt; &#xA;&lt;a href=&quot;https://i.stack.imgur.com/6Z9KI.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6Z9KI.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="111" LastEditDate="2016-07-05T02:40:08.733" LastActivityDate="2016-07-05T02:40:08.733" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6949" PostTypeId="2" ParentId="6947" CreationDate="2015-11-18T04:21:10.853" Score="4" Body="&lt;p&gt;To add to Gordon's answer, Cyclone Twenty-five was also called Cyclone Raquel and it was an &quot;off-season&quot; cyclone, as the following &lt;a href=&quot;http://www.abc.net.au/news/2015-07-01/rare-off-season-cyclone-forms-near-solomon-islands/6587690&quot; rel=&quot;nofollow noreferrer&quot;&gt;reported in the news&lt;/a&gt;. It was the &lt;a href=&quot;http://www.abc.net.au/news/2015-07-01/cyclone-in-july-weather-bureau-declares-raquel-no-threat/6585580&quot; rel=&quot;nofollow noreferrer&quot;&gt;first cyclone recorded in the region during July&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The synoptic weather map the region on that day was&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pYHLz.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pYHLz.gif&quot; alt=&quot;West Pacific Weather Map&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://www.bom.gov.au/cgi-bin/charts/charts.view.pl?idcode=IDX0016&amp;amp;file=IDX0016.201506300000.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.bom.gov.au/cgi-bin/charts/charts.view.pl?idcode=IDX0016&amp;amp;file=IDX0016.201506300000.gif&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2015-11-18T04:26:25.880" LastActivityDate="2015-11-18T04:26:25.880" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6950" PostTypeId="2" ParentId="6947" CreationDate="2015-11-18T04:46:09.613" Score="9" Body="&lt;p&gt;The formation of twin cyclones does occur in both the Indian Ocean as well as the Western Pacific with the Indian Ocean twins being weaker . Schubert et al &lt;a href=&quot;http://schubert.atmos.colostate.edu/publications/refereed/nietoetal1996_dynamical.pdf&quot; rel=&quot;noreferrer&quot;&gt;Symmetric Twin Tropical Cyclones&lt;/a&gt; report that the October through May is the period of formation of twin tropical cyclones with December through February being the maximum frequency. The original definition of twin tropical cyclones was provided by Keen in 1982 &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0493%281982%29110%3C1405%3ATROCET%3E2.0.CO%3B2&quot; rel=&quot;noreferrer&quot;&gt;Cross Equatorial Pairs in the Southern Oscillation&lt;/a&gt;. Apart from high SSTs you also need conditions of intense low level  vorticity. The convection associated with the eastward propagating Madden Julien Oscillation(MJO) contains cyclonic Rossby gyres that favour tropical cyclogenesis.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If students are wondering what and where are the cyclonic gyres this image may help in that regard- please pay attention to the cyclonic gyres at the 850 hPa level that trail the convection&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Uv3ZX.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Uv3ZX.gif&quot; alt=&quot;MJO 3D structure&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lander in &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0493%281990%29118%3C1194%3AEOTCPD%3E2.0.CO%3B2&quot; rel=&quot;noreferrer&quot;&gt;Formation of Twin Tropical Cyclone Twins Symmetrical With Respect to the Equator &lt;/a&gt; outline the &quot;Keen criteria&quot; &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The northern and southern systems must initially form within 9 days of each other&lt;/li&gt;&#xA;&lt;li&gt;Latitudinal separation must not be more than 22 degrees&lt;/li&gt;&#xA;&lt;li&gt;The longitudinal difference of the initial disturbances ranged between +9 degrees and -17 degrees&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;A further strict definition for twins include&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;They must form simultaneously&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;They form at low latitudes (5 degrees above and below the equator) &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;They form along the same longitude&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Lander performs case studies for the twin cyclones Lola and Namu in the 1986 Pacific Typhoon season - &lt;a href=&quot;https://en.wikipedia.org/wiki/1986_Pacific_typhoon_season&quot; rel=&quot;noreferrer&quot;&gt;1986 Pacific Typhoon Season&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A more recent reference Schreck et al. &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/2008MWR2541.1&quot; rel=&quot;noreferrer&quot;&gt;A case study of an outbreak of twin tropical cyclones&lt;/a&gt; have performed studies that conclude that a broad and long lasting envelope of warm water, low surface pressure and easterly shear are other conditions that are required for formation of twin cyclones. &#xA;Students can watch the video in this URL &lt;a href=&quot;https://www.climate.gov/news-features/event-tracker/twin-tropical-cyclones-western-pacific&quot; rel=&quot;noreferrer&quot;&gt;Cyclone Pam and Bavi&lt;/a&gt; and see the twin cyclone activity&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2015-11-18T08:12:35.733" LastActivityDate="2015-11-18T08:12:35.733" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6951" PostTypeId="2" ParentId="2639" CreationDate="2015-11-18T08:10:31.287" Score="0" Body="&lt;p&gt;Question;&#xA;&lt;strong&gt;Given that, how many trees would I need to plant to solve the global climate change crisis? Should I optimize for a specific type of tree, or would pine work as well as oak or black walnut?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;First, you need to think it as a forest. In a forest there are also trees which lose the game of evolution in addition to trees that win.&lt;/p&gt;&#xA;&lt;p&gt;Second, you need to look where (in terms of climate) your forest is, and what's its soil. This defines the tree type.&lt;/p&gt;&#xA;&lt;p&gt;Third, you need to cut your forest on time to optimize it' growth rate. 26 years is optimum, so roughly 4 times a century.&lt;/p&gt;&#xA;&lt;p&gt;This way you can &lt;a href=&quot;http://www.puuproffa.fi/PuuProffa_2012/7/puun-kasvu/metsan-kasvu&quot; rel=&quot;nofollow noreferrer&quot;&gt;reach growth rates like 4.8 tn/ha/year in Finland&lt;/a&gt; or&lt;br /&gt;&#xA;&lt;a href=&quot;http://www.forestresearchgroup.com/Newsletters/V8No2.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;5.16 tons/acre/year in the USA.&lt;/a&gt; I am not sure about the unit used in this source, but if their ton is 907 kg and an acre is 4046.85 m&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt;, this results in 11.56 tn/ha/year.&lt;/p&gt;&#xA;&lt;p&gt;If the used carbon amount is &lt;span class=&quot;math-container&quot;&gt;$9.2 \times 10^9$&lt;/span&gt; tons, and &lt;a href=&quot;http://www.fpl.fs.fed.us/documnts/pdf1984/pette84a.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;half of wood weight is carbon&lt;/a&gt; then you need &lt;span class=&quot;math-container&quot;&gt;$1.6 \times 10^9$&lt;/span&gt; ha or 16 000 000 km&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt; of forest.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Forest#Forest_land_area&quot; rel=&quot;nofollow noreferrer&quot;&gt;There is 39 500 000 km&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt; of forest in the world.&lt;/a&gt;&#xA;If 40% of it is used optimally, it would be enough at present rates. The CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; concentration is not a problem; human population growth is.&lt;/p&gt;&#xA;" OwnerUserId="3098" LastEditorUserId="18081" LastEditDate="2020-12-04T07:44:58.460" LastActivityDate="2020-12-04T07:44:58.460" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="6953" PostTypeId="1" CreationDate="2015-11-18T17:30:29.697" Score="6" ViewCount="2016" Body="&lt;p&gt;In a sandstorm, is there a buildup of static electricity? If so, does that produce lightning strikes? Also if you were to be inside the storm what would the build of that level of static feel like?  &lt;/p&gt;&#xA;" OwnerUserId="4787" LastEditorUserId="28050" LastEditDate="2015-11-19T01:15:13.383" LastActivityDate="2015-11-19T01:17:12.030" Title="Is there a buildup of static electricity in a sandstorm?" Tags="|desert|storms|electromagnetism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6954" PostTypeId="2" ParentId="6953" CreationDate="2015-11-19T00:52:32.390" Score="7" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Dust_storm&quot;&gt;Sandstorms&lt;/a&gt; occur in dry areas, particularly deserts. The sand particles are fairly uniform in size. As the dry sand moves due to the wind it begins a leaping process known as saltation. Quoting the &lt;a href=&quot;https://en.wikipedia.org/wiki/Dust_storm&quot;&gt;Wikipedia article&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the initial saltation of sand particles induces a static electric field by friction&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The sand particles become polarized and as the particles begin to hit each other the polarization on each grain gets rearranged and the degree of polarization doubles with each interaction. With a build up of static electric charge &lt;a href=&quot;http://www.technologyreview.com/view/418236/how-sandstorms-generate-spectacular-lightning-displays/&quot;&gt;lightning can develop&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The greatest build up of static charge occurs in sandstorms of &lt;a href=&quot;http://www.livescience.com/8195-mystery-sandstorm-lightning-explained.html&quot;&gt;intermediate thickness&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="28050" LastEditDate="2015-11-19T01:17:12.030" LastActivityDate="2015-11-19T01:17:12.030" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6956" PostTypeId="2" ParentId="6918" CreationDate="2015-11-19T15:52:31.600" Score="4" Body="&lt;p&gt;I will try to bring you some insights. In my opinion, SCA is poorly named.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Actually, the width is not involved in the catchment area which is given by TCA. SCA introduces a diffusive flow factor by considering flow width. It is a one dimensional value so it is not representative of an area and that's why it might be confusing. It gives us an idea of how concentrated are the incoming flow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Besides this, I think you are also confused by the outlet concept which is often defined in GIS or in some conceptual definitions by a point. But actually, in order to compute a flow at an outlet you need flow velocity and a cross section. If this cross section area is assumed to be rectangular, it can be defined by the width and the height will vary according to the incoming flow. So when the outlet is considered as a point, it is more like a targeter of the outlet that has some dimensional characteristics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, for studies at the plot scale or the hillslope scale, the outlet is often defined by a line which is representative of the flow width at the downslope.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For grid based data, a pour point targets a representative area defined by the spatial resolution of your terrain data. If a point has no flow width, this area has one and the flow width is generally assumed to be the cell size as mentionned in your quote.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you understand that, you may understand that the broader the width, the more diffuse will be the overland flow and therefore the less wet regarding the TWI or the less erosive. Of course, it remains resolution dependent.&lt;/p&gt;&#xA;" OwnerUserId="3363" LastActivityDate="2015-11-19T15:52:31.600" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6957" PostTypeId="1" CreationDate="2015-11-19T15:56:26.317" Score="3" ViewCount="350" Body="&lt;p&gt;What is the relation between &lt;a href=&quot;https://en.wikipedia.org/wiki/Biochemical_oxygen_demand&quot; rel=&quot;nofollow&quot;&gt;biological oxygen demand&lt;/a&gt; (BOD) and depth? I need to calculate the BOD of a drinking water tank and I have ultimate BOD at the surface of water, but I need to calculate it when depth varies. My calculations need an equation of de-oxygenation constant rate and BOD.&lt;/p&gt;&#xA;" OwnerUserId="4845" LastEditorUserId="28050" LastEditDate="2015-11-20T13:21:29.677" LastActivityDate="2016-12-25T16:18:40.217" Title="How are biological oxygen demand and depth related?" Tags="|hydrology|water|groundwater|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="6958" PostTypeId="1" CreationDate="2015-11-19T16:36:40.237" Score="3" ViewCount="131" Body="&lt;p&gt;According to &lt;a href=&quot;https://www.youtube.com/watch?v=fvoCzunex3I&quot; rel=&quot;nofollow&quot;&gt;this Discovery News video about Centralia Pennsylvania and other underground coal fires&lt;/a&gt;, there are many smouldering underground coal reserves making the land above it uninhabitable to humans. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One possible solution I thought of for extinguishing an underground coal fire might be to invent the technology to affect weather patterns and then create a continuous rainfall overhead so the water will drain down to the coal putting it out. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it's a very risky for people to make any big change to the Earth without first getting a research group to very carefully research whether it might cause a nasty problem later that they didn't think of. For example, maybe if every time a coal reserve catches on fire, people put in out, then the earth will start producing coal faster than it's getting depleted by natural process and eventually it will have such a huge buildup of coal that if a it catches on fire and doesn't get put out right away, it will grow too big to be able to put out and will then spread all over the entire continent. &lt;/p&gt;&#xA;" OwnerUserId="4846" LastEditorUserId="6129" LastEditDate="2020-05-08T06:12:40.537" LastActivityDate="2020-05-08T06:12:40.537" Title="Is there a risk with putting out smouldering underground coal reserves?" Tags="|geophysics|geochemistry|precipitation|coal|" AnswerCount="2" CommentCount="3" ClosedDate="2015-11-26T04:16:02.423" ContentLicense="CC BY-SA 3.0" />
  <row Id="6959" PostTypeId="2" ParentId="6958" CreationDate="2015-11-19T18:12:43.883" Score="7" Body="&lt;p&gt;There isn't a risk to putting it out other than the attempt failing, it is just impractical to do so once a large coal vein catches fire.  You can read more about the &lt;a href=&quot;https://en.wikipedia.org/wiki/Centralia,_Pennsylvania#Mine_fire&quot;&gt;Centralia, PA coal fire on wikipedia&lt;/a&gt; which sits on top of anthracite coal veins that have been burning for a little over 50 years and are likely to continue to do so for a few hundred years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your proposed idea of &quot;inventing weather modification&quot; is not practical. While we have the technology to seed clouds and produce localized rainfall this still depends on the amount of water vapor in the air.  You can bypass evaporating water into the atmosphere, seeding clouds and raining and instead just pump water into the mines and flood them.  That will be much more efficient at getting water into the mines.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So why don't they flood the mines?  That too is not practical, and if memory serves me right, they did try that in Centralia.  The problems are&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Mines open into cave systems&lt;/li&gt;&#xA;&lt;li&gt;Water can flow through very small openings&lt;/li&gt;&#xA;&lt;li&gt;Coal needs only be hot and in the presence of oxygen to burn.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;This means you'll need to keep the coal underwater, isolated from oxygen until you can dissipate all of the geothermal heat mass that has built up in the surrounding rocks from the burning coal.  You'll also have to make the mine water tight in order to flood it.  You'll also need a way to deal with your flood water evaporating and steam build up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Faced with the realization that extinguishing these fires is impractical the decisions were made to abandon the towns.  There was no real risk in putting the fire out, it just isn't practically possible to do so.  The risk in letting the fire continue to burn was abated by evacuating the town permanently.  Burning coal does not effect the production of new coal (that takes a long time on geological time scales) -- burning coal is a net reduction in coal mass, not a gain.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;As an aside, the other problem with cloud seeding, specifically with the Centralia, PA case, is legal.  Pennsylvania farmers were so concerned about the possibility of cloud seeding elswehere in the state depriving them of needed rainfall that in 1968 the PA state legislature passed &quot;&lt;a href=&quot;http://www.legis.state.pa.us/WU01/LI/LI/US/PDF/1967/0/0449..PDF&quot;&gt;WEATHER MODIFICATION - REGULATING RAIN MAKING. Act of Jan. 19, (1968) 1967, P.L. 1024, No. 449&lt;/a&gt;&quot; which means you'll need to convince the state to issue a license for your activities, which is not likely to be granted.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2015-11-19T18:19:48.483" LastActivityDate="2015-11-19T18:19:48.483" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6960" PostTypeId="2" ParentId="6958" CreationDate="2015-11-19T20:01:32.097" Score="3" Body="&lt;p&gt;Nice idea but the practicalities are impossible. There are parts of Indonesia which have out-of-control peat and coal fires which have been raging for years, and even decades, despite those areas receiving well in excess of two metres of rain a year. &#xA;See for example: Whitehouse AE and Mulyana AAS, (2004) &lt;em&gt;Coal Fires in Indonesia.&lt;/em&gt; International Journal of Coal Geology, 59, 1-2, pages 91-97.&#xA;It's true that some of the fires burn out during particularly wet years, but the sting in the tail is that the heat of hydration of dry coal tends to reignite the coal again during the dry season. Be assured that if there was a simple economic solution, it would have been tried by now. Some not so simple solutions are under trial, such as smothering the fire with nitrogen foam.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-11-19T20:01:32.097" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6961" PostTypeId="1" CreationDate="2015-11-20T10:55:37.053" Score="5" ViewCount="82" Body="&lt;p&gt;I want to do frequency analysis of drought severity, but unlike precipitation data here I have few zero values in some of the years. how to do this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is the sample data:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;1981    -1.34836065669339&#xA;1982    -1.35038460644290&#xA;1983    0&#xA;1984    -3.90332570519887&#xA;1985    -1.43196467810065&#xA;1986    0&#xA;1987    -7.61244713754898&#xA;1988    -1.02963066829013&#xA;1989    -2.87025610581835&#xA;1990    0&#xA;1991    -1.66903948845324&#xA;1992    -1.09433029589075&#xA;1993    -2.66739065155971&#xA;1994    -3.01088239849460&#xA;1995    0&#xA;1996    0&#xA;1997    -14.0056988537627&#xA;1998    0&#xA;1999    -9.85363948490749&#xA;2000    -1.36158063667645&#xA;2001    -5.34791858336523&#xA;2002    -3.11969637720832&#xA;2003    0&#xA;2004    -3.62559721791381&#xA;2005    -2.08214497384456&#xA;2006    -4.80944910848512&#xA;2007    -1.42804069956900&#xA;2008    -5.37009474560193&#xA;2009    -13.0916410702083&#xA;2010    -2.36624662191914&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="5330" LastActivityDate="2015-11-20T10:55:37.053" Title="How to do frequency analysis of an index when some years have zero value?" Tags="|climate-change|statistics|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="6962" PostTypeId="1" CreationDate="2015-11-21T04:54:53.347" Score="6" ViewCount="567" Body="&lt;p&gt;Deforestation is an ongoing global problem. From this &lt;a href=&quot;http://environment.nationalgeographic.com/environment/global-warming/deforestation-overview/&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Geographic webpage&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The quickest solution to deforestation would be to simply stop cutting down trees. [However], financial realities make this unlikely to occur. ... A more workable solution is to carefully manage forest resources by eliminating clear-cutting to make sure that forest environments remain intact. ... The number of new tree plantations is growing each year, but their total still equals a tiny fraction of the Earth’s forested land.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;How much forested land is currently protected from logging/deforestation?  How much is currently at risk?  How do tree plantations compare in overall size?  I'm hoping someone could answer these questions in terms of the main countries involved.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is what I have found thus far:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;http://www.earth-policy.org/indicators/C56&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.earth-policy.org/indicators/C56&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Forests cover 31 percent of the world's land surface, just over 4 billion hectares. This is down from the pre-industrial area of 5.9 billion hectares. ... According to data from the U.N. Food and Agriculture Organization [below], deforestation was at its highest rate in the 1990s, when each year the world lost on average 16 million hectares of forest—roughly the size of the state of Michigan. At the same time, forest area expanded in some places, either through planting or natural processes, bringing the global net loss of forest to 8.3 million hectares per year.  In the first decade of this century, the rate of deforestation was slightly lower, but still, a disturbingly high 13 million hectares were destroyed annually. As forest expansion remained stable, the global net forest loss between 2000 and 2010 was 5.2 million hectares per year. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0WQQw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0WQQw.png&quot; alt=&quot;World Forest Cover, 1990 -2010&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;South America and Africa are clearly the biggest area of concerns due to illegal logging and corrupt governance.  Should we expect the rates of deforestation in those continents to continue &quot;as-is&quot;?  Or is there some percentage of forested areas that can be expected to last (e.g. perhaps some countries are less corrupt)? Furthermore, if the size of forested land on N. America, Asia, and Europe remains constant or grows, how much of that is due to tree plantations?&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2015-11-29T17:52:03.130" LastActivityDate="2017-04-30T23:08:44.773" Title="How much of Earth's forested land is currently protected from logging/deforestation?" Tags="|climate-change|forest|deforestation|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="6963" PostTypeId="1" AcceptedAnswerId="6966" CreationDate="2015-11-21T21:09:32.397" Score="4" ViewCount="154" Body="&lt;p&gt;I've heard that dry ice, iodides have been used as seeding agents to &lt;em&gt;induce rainfall&lt;/em&gt;. Is this technique really being used widely? What are the prerequisites for initiating seeding? Is it as bounteous as natural rainfall is?&lt;/p&gt;&#xA;" OwnerUserId="4859" LastActivityDate="2015-11-22T08:29:46.303" Title="How effective is seeding rainclouds? What are the indications for initiating seeding?" Tags="|rainfall|rain|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6964" PostTypeId="1" CreationDate="2015-11-22T02:19:31.503" Score="8" ViewCount="176" Body="&lt;p&gt;&lt;strong&gt;About the code:&lt;/strong&gt; I have a code which simulates concentration from advection-diffusion-reaction PDE in 2D space (X,Y) with time. The solution is obtained using fully implicit finite-difference method and includes the capability to simulate a media with spatially varying permeability and reaction constant (through upwinding by harmonic mean). I have been able to test the code for homogeneous media and it works fine. It's a solution for the following equation:&#xA;$$\begin{align}&#xA;\frac{\partial C}{\partial t} + \nabla.\left(v  C - D\nabla{C} \right)=  \alpha C&#xA;\end{align}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Issue:&lt;/strong&gt; The code gives realistic solution for a medium with uniform layers of permeability as shown below. However, once the medium starts to get more heterogeneous it starts to throw unrealistic results (i.e. negative concentration and large fluctuations with time). Any guesses why I am getting unrealistic results for heterogeneous media (with values in the similar range as uniform layered media)? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE:&lt;/strong&gt; I think I have figured the issue for getting negative values and sharp fluctuations in concentration. I think the problem is not with the numerical model, but with the physical values. Even though I was already taking realistic parameter values for which I was getting unrealistic concentration, I had to further adjust them (decrease the convection velocity) to get realistic results&lt;/p&gt;&#xA;" OwnerDisplayName="user3153" LastEditorUserId="1242" LastEditDate="2015-11-29T22:01:13.423" LastActivityDate="2015-11-29T22:01:13.423" Title="Unrealistic solution for advection-diffusion-reaction PDE with heterogeneous porous media" Tags="|hydrology|numerical-modelling|fluid-dynamics|hydrogeology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6965" PostTypeId="2" ParentId="6964" CreationDate="2015-11-22T08:01:51.457" Score="2" Body="&lt;p&gt;It's not clear exactly what is being modelled here, but it seems to me that there are two ways in which the concentration can 'go negative'. Firstly, the rate of change of concentration can be massive, in which case see what happens when modelling with much smaller time steps. Or, the diffusion term substantially exceeds the advection term, which is physically unlikely. However, you are modelling a large (more than 10-fold) anisotropy, in which almost all the flow will be in the x, horizontal direction - it is almost a one-dimensional problem in fact. So how can the advection be less than the diffusion? In the case of a constant concentration source, such as a saline water body, the negative results don't make sense, in which case the calculations have gone unstable, probably from using too large a time step. In the case of a pulsed source, as the concentration peak passes (along the x direction), the advected concentration rises and falls, such that the lateral (y axis) diffusion increases, then decreases, i.e. the concentration gradient changes direction, becoming negative.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As if this wasn't hard enough, in real life applications the 'sink' terms probably far exceed any back-diffusive effects. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-11-22T08:01:51.457" CommentCount="13" ContentLicense="CC BY-SA 3.0" />
  <row Id="6966" PostTypeId="2" ParentId="6963" CreationDate="2015-11-22T08:29:46.303" Score="4" Body="&lt;p&gt;Cloud seeding has been attempted for well over a century, with mixed success. There is no doubt at all that, &lt;em&gt;locally&lt;/em&gt;, rain can be increased by seeding the cloud base with such nucleating agents as dry ice or silver iodide smoke. There is a great deal of doubt as to whether there is any overall gain in rainfall - or is it just an expensive way of 'robbing Peter to pay Paul', of increasing rain in one location at the expense of rainfall further downwind. Is there any nett gain in regional rainfall? Probably not. Of course, there are many cases where &lt;em&gt;locally&lt;/em&gt; increased rainfall may be worth the effort. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not all cases of cloud seeding work. There are several requirements. First, the process involves vigorous convection within the cloud towers in order to loft the nucleating agent into a sufficiently super-cooled part of the cloud. If the cloud is too warm it won't work - which rules out many tropical applications. Second, the 'seed' has to be injected into the cloud base at about -10 to -20 deg C, which allows 'graupel' to form, i.e. a kind of granular ice that flash freezes onto snow or ice crystals direct from super-cooled water vapour. Third, the timing has to be right, just as the cumulus towers are beginning to form, usually in the early afternoon. Fourthy, the economics are very moot. Wikipedia ('Cloud Seeding') claims that the subject is no longer 'fringe science', which is true in that the physics have been studied seriously, but mostly untrue in the sense that it is now considered economically attractive. The great majority of studies have shown that cloud seeding is unreliable, expensive, and of dubious value, with other ways of delivering water (such as desalination) being a better bet. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-11-22T08:29:46.303" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6967" PostTypeId="1" AcceptedAnswerId="6968" CreationDate="2015-11-22T13:14:08.000" Score="6" ViewCount="4038" Body="&lt;p&gt;The question is clear enough in my opinion but, I've found out that if you redraw this picture here: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/1/12/Seasons.svg/1920px-Seasons.svg.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/1/12/Seasons.svg/1920px-Seasons.svg.png&quot; alt=&quot;&amp;quot;Seasons&amp;quot;, as from Wikipedia&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You'll notice that the Sun is as big as the Earth. But if you scale up the Sun to it's real size compared to the Earth, you would realize that the Earth would covered in daylight ALL THE TIME. So what's going on here?&lt;/p&gt;&#xA;" OwnerUserId="4861" LastEditorUserId="4861" LastEditDate="2019-11-01T15:26:55.880" LastActivityDate="2019-11-01T15:26:55.880" Title="Why wouldn't the earth be &quot;always daytime&quot; if the &quot;daily cycle of sunlight&quot; was drawn full-scale?" Tags="|earth-observation|solar-terrestrial-physics|seasons|diurnal-cycle|scaling|" AnswerCount="5" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="6968" PostTypeId="2" ParentId="6967" CreationDate="2015-11-22T13:25:26.667" Score="16" Body="&lt;p&gt;The sun is &lt;a href=&quot;https://en.wikipedia.org/wiki/Astronomical_unit&quot; rel=&quot;nofollow noreferrer&quot;&gt;really far away&lt;/a&gt;. Thus its rays are &lt;a href=&quot;https://physics.stackexchange.com/questions/155075/what-makes-suns-light-travel-as-parallel-beams-towards-earth&quot;&gt;essentially parallel&lt;/a&gt; at the earth's orbit. So, while the diagram you posted is clearly a bit off in terms of the relative size and distance between the sun and the earth, the parallel rays are about right.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/L4pXa.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/L4pXa.png&quot; alt=&quot;Sun and Earth - public domain image&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="-1" LastEditDate="2017-04-13T12:40:15.470" LastActivityDate="2015-11-22T14:00:12.443" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6969" PostTypeId="2" ParentId="6967" CreationDate="2015-11-22T19:11:03.257" Score="6" Body="&lt;p&gt;Given the known average distance to the Sun, and the radii of Sun and Earth, the basic trigonometry is simple. &#xA;If the Earth and Sun were exactly the same size, and there was no atmospheric refraction, then exactly half the planet, or 180 degrees, would be illuminated. But since the Sun is so much bigger, again assuming no atmospheric refraction, then exactly 180.522 degrees of the Earth would be illuminated. Calculating the additional illumination caused by atmospheric refraction of sunlight into the zone of darkness is fraught with difficulty because of variable atmospheric haze, temperature-controlled differences in air density, and cloud distribution. I'm guessing you could add a degree or two more if you were to include refracted twilight.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-11-22T19:11:03.257" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6970" PostTypeId="2" ParentId="6967" CreationDate="2015-11-22T20:19:45.623" Score="11" Body="&lt;p&gt;The sun is about 100 times the size of the Earth (in diameter), and the distance from the sun to Earth is about 100 times the diameter of the sun. &lt;strong&gt;&lt;em&gt;Below&lt;/em&gt;&lt;/strong&gt; is an image showing the sun, Earth, and the distance between them to scale. It looks at first like nothing more than a black bar. This image in the original is &lt;strong&gt;&lt;em&gt;4000&lt;/em&gt;&lt;/strong&gt; pixels (the limit of my Pixlr Editor) by 60 pixels, and Earth is less than a pixel. To see it full size, &lt;a href=&quot;https://i.stack.imgur.com/YTpMm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;click here&lt;/a&gt; or on the image, then when it comes up in your web browser click on it again to magnify it to full size. Use your scroll bar to see the sun at one end and Earth at the other. You will need to look &lt;strong&gt;&lt;em&gt;really&lt;/em&gt;&lt;/strong&gt; closely to see Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YTpMm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YTpMm.png&quot; alt=&quot;the sun, Earth, and the distance between them to scale - public domain image&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4487" LastEditorUserId="4487" LastEditDate="2015-11-22T21:23:26.250" LastActivityDate="2015-11-22T21:23:26.250" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="6971" PostTypeId="1" AcceptedAnswerId="6974" CreationDate="2015-11-22T20:24:20.887" Score="6" ViewCount="207" Body="&lt;p&gt;If you were to stand on a tall building in Washington, DC and looked west, how tall would the building need to be to see Los Angeles? I would like answers based on if the world was flat and if the world was round. The distance is 2300 miles from &lt;a href=&quot;http://www.timeanddate.com/worldclock/distanceresult.html?p1=263&amp;amp;p2=137&quot;&gt;Washington, DC to Los Angeles&lt;/a&gt;, California. According to &lt;a href=&quot;http://www.davidsenesac.com/Information/line_of_sight.html&quot;&gt;Visual Line of Sight Calculations&lt;/a&gt;, the Earth's curvature has an average curvature of 7.98 inches per mile.&lt;/p&gt;&#xA;" OwnerUserId="4864" LastEditorUserId="4864" LastEditDate="2015-11-22T21:33:08.927" LastActivityDate="2015-11-23T02:32:22.710" Title="How high do you need to be to see Los Angeles from Washington DC?" Tags="|geophysics|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6973" PostTypeId="2" ParentId="2324" CreationDate="2015-11-22T23:53:43.323" Score="6" Body="&lt;p&gt;&lt;strong&gt;&lt;em&gt;Somewhat more from volcanic activity than meteor impacts, but both are important.&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth has an &lt;a href=&quot;http://en.wikipedia.org/wiki/Structure_of_the_Earth#Core&quot; rel=&quot;nofollow&quot;&gt;iron-nickel ($\ce{Fe}$-$\ce{Ni}$) core&lt;/a&gt; that originates from Earth's formation out of the collision of &lt;a href=&quot;http://en.wikipedia.org/wiki/Planetesimal&quot; rel=&quot;nofollow&quot;&gt;planetesimals&lt;/a&gt; which themselves contained iron, rock and ice. The Earth was very hot at that time, and the iron along with some &lt;a href=&quot;http://en.wikipedia.org/wiki/Goldschmidt_classification#Siderophile_elements&quot; rel=&quot;nofollow&quot;&gt;siderophilic elements&lt;/a&gt; sunk to the center to form the core. Relatively little of that iron is in the crust. It is mostly &lt;a href=&quot;http://www.researchgate.net/profile/B_Wood4/publication/7004632_Accretion_of_the_Earth_and_segregation_of_its_core/links/54e48d180cf2dbf60696e081.pdf&quot; rel=&quot;nofollow&quot;&gt;sequestered in the core (pages 326, 327)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The iron that is mined on Earth is mostly from &lt;a href=&quot;http://en.wikipedia.org/wiki/Banded_iron_formation&quot; rel=&quot;nofollow&quot;&gt;banded iron formation from geochemical leeching of basalts and subsequent sedimentary depositing of the iron oxides in anoxic ocean beds&lt;/a&gt;. But &lt;a href=&quot;http://en.wikipedia.org/wiki/Sudbury_Basin#Modern_uses&quot; rel=&quot;nofollow&quot;&gt;some of the best iron ore and native metal alloy deposits come from iron meteorite impacts&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="4487" LastEditorUserId="543" LastEditDate="2015-12-05T06:28:32.337" LastActivityDate="2015-12-05T06:28:32.337" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6974" PostTypeId="2" ParentId="6971" CreationDate="2015-11-23T02:32:22.710" Score="8" Body="&lt;p&gt;The website you provide a link for gives the horizon distance as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$d$ $\approx$ $1.23\sqrt{h}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where d is in miles and h is height above ground level in feet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rearranging the equation&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$h$ $\approx$ $(d/1.23)^2$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a horizon distance of 2300 miles, the height would have to be 3,496,596 feet, or 662.2 miles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a flat Earth, it depends on the height of any obstacles between Washington DC &amp;amp; LA and the distance the obstacle is from either LA or Washington. If there are no obstacles, no height is required as light from LA can travel across the flat plane to Washington.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to account for impedance provided by the Rocky Mountains, use Google Earth &amp;amp; draw a line between LA &amp;amp; Washington. A high point of around 9600 feet occurs some 780 miles from LA.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By using similar triangles such a height at Washington would be 28,308 feet.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-11-23T02:32:22.710" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="6975" PostTypeId="1" CreationDate="2015-11-23T05:49:22.357" Score="4" ViewCount="157" Body="&lt;p&gt;I am working on a project in predicting the weather and I had a few brief questions.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;I understand that radar works by bouncing waves off of precipitation and measuring reflectivity. I have a variable and the definition for the variable is as follows, &lt;strong&gt;&quot;10th percentile of reflectivity values in 5x5 neighborhood around the gauge.&quot;&lt;/strong&gt; Can someone please explain this? I am guessing that this means it measures the strength of the signal returning from a 5x5 area around the measuring gauge? Is this correct? What does it mean that it is in the 10th percentile? The 50th percentile? The 90th?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The next variable is, &lt;strong&gt;&quot;Maximum reflectivity values in the vertical column above gauge in dBZ&quot;&lt;/strong&gt;. I know that dBZ is used to measure reflectivity, but what does it mean in the vertical column above the gauge?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;I understand Correlation Coefficient to be the measure of how similarly the horizontally and vertically polarized pulses are behaving within a pulse volume. Can someone please tell me what a pulse volume is?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I really appreciate any help. Most answers I found through my own digging, but I really need help to understand these few questions.&lt;/p&gt;&#xA;" OwnerUserId="4870" LastEditorUserId="64" LastEditDate="2015-11-24T16:01:06.000" LastActivityDate="2015-11-24T20:00:50.957" Title="Need help understanding variables that relate to meterology terminology" Tags="|meteorology|precipitation|remote-sensing|weather-forecasting|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6976" PostTypeId="2" ParentId="6967" CreationDate="2015-11-23T11:11:00.900" Score="7" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;But if you scale up the Sun to it's real size compared to the Earth,&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Is pretty big. But then to be realistic in that manner you would also have to scale up the distance from the earth to the sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But you don't have to even do that, as there is a much simpler way of seeing how large the sun is from the perspective of a position on the earth.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Be on or very near to the earth (you are probably already achieving this).&lt;/li&gt;&#xA;&lt;li&gt;Look at the sky.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;If it's daytime and not cloudy you should see the sun up there somewhere (please don't keep looking…). It's not very big, about 32′ (varies slightly) which is just slightly bigger than 0.5°.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's about the same as the moon (or else transits wouldn't be the interesting-looking eclipses that we get). Or about the size of the princess' thumb at arm's length in the story of the princess who wanted the moon for her birthday.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's not enough to bathe most of the earth in the sun's rays. It's just about enough for almost half to be lit, almost half to be dark, and to have a period where a given point of the earth is illuminated by some, but not all, of the sun's visible disc. You can see this by the same look-at-the-sky experiment, by looking toward the horizon during sunrise or sunset.&lt;/p&gt;&#xA;" OwnerUserId="4873" LastEditorUserId="4873" LastEditDate="2015-11-23T16:36:02.973" LastActivityDate="2015-11-23T16:36:02.973" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6977" PostTypeId="2" ParentId="6967" CreationDate="2015-11-23T14:55:44.473" Score="3" Body="&lt;p&gt;Because no matter how big the Sun is compared to the Earth, only half the Earth can be facing the Sun at any given time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Try drawing a diagram where the Sun is much bigger with respect to the Earth. Make it ten times or a hundred times bigger or go all out and draw it to scale. Suppose it to be so big that it doesn't even look like a circle,  but just a straight line of infinite length. Still, only half the Earth is facing it at any given time. Unless sunlight can penetrate the Earth, or somehow leaks around the edges, half the Earth will still be dark.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Update&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ahhh, I see where you're coming from now. Okay, true, if the Sun was infinitely large, or at least extremely large and extremely close, and if light left any given point on the surface of the Sun travelling in all directions, then yes, light rays could reach parts of the Earth not facing toward the Sun. They couldn't actually reach the point on the exact opposite side, but I guess close enough. I confess, I was thinking of light rays travelling from the Sun to the Earth in a direction parallel to a straight line from the center of the Earth to the center of the Sun. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suppose that all light leaving the surface of the Sun is not travelling directly outward from the center, so to that extent, your model is plausible. Frankly I don't know enough about the physics to say how close that resembles reality. I'd think more light is travelling directly out from the center than at tangents, because the Sun is not a dark core with a thin glowing surface, but rather produces light from within. I have no idea what the relative numbers are though. But I guess the question is not the amount of light, but any light. So let's accept your model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So yes, if the Sun was big enough and close enough, light from, say, the north pole of the Sun could hit a point on the &quot;far side&quot; of the Earth at a tangent. As in my diagram.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In real life, though, it's not THAT big or THAT close. Let's run the numbers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/p7iPL.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/p7iPL.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let $s$ be the distance from the Earth to the Sun, $r$ the radius of the Sun, and $A$ the angle along the curve of the Earth from the north pole. Then we have the triangle shown below, where $h$ is the height of the triangle. The radius of the Earth is very small compared to all the other numbers here, and so basically gets lost in the rounding. As $s$ is very large compared to $r$, $h$ is very close to $r$, so just to keep the geometry simple, let's assume $h=r$. (As $r \ge h$, calculating the real value for $h$ hurts your case.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So geometry tells us that $r=s * \sin A$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Sun is about 93 million miles away. So for light rays in this scenario to reach 45 degrees past the Earth's north pole, we'd have:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;r = 93,000,000 * \sin(45) \\&#xA;r = 93,000,000 * \frac{\sqrt 2}{2} \\&#xA;r \approx 65,000,000 \\&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is, the radius of the sun would have to be more than 65 million miles. In real life it's nowhere near that, it's more like 432,000.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So how far past the pole can the light really bleed?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;h \ge s * \sin A \\&#xA;\sin A \le h / s \\&#xA;\sin A \le \frac {432,000}{93,000,000} \\&#xA;\sin A \le .004645 \\&#xA;A \le 0.266 °\\&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is, sunlight can &quot;bleed&quot; past the pole by about 1/4 of 1 degree.&lt;/p&gt;&#xA;" OwnerUserId="4874" LastEditorUserId="20" LastEditDate="2015-11-29T21:31:36.357" LastActivityDate="2015-11-29T21:31:36.357" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="6978" PostTypeId="2" ParentId="4999" CreationDate="2015-11-23T15:17:02.413" Score="4" Body="&lt;p&gt;Zounds, good point! I guess the world is flat after all! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But okay, seriously, the writer has given a good and accurate argument why it should be possible to tell whether the world is round or flat by making observations on the ocean or a sufficiently large sea. But as far as the quoted page goes, he doesn't cite any experimental results to prove anything, one way or the other. To say, &quot;I can imagine an experiment which would prove my theory correct&quot; is a long way from &quot;I have conducted this experiment and the results actually did prove my theory correct.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact, making observations across an ocean or large sea is one of the easiest proofs that the world is round. It was observed in the days of sailing ships that as a &quot;tall ship&quot; sailed away, the last thing you would see was the top of its sails. Look across a sufficiently large sea today and, no matter how clear the skies, etc, you cannot see the opposite shore. Get the most powerful telescope available and you still can't see the opposite shore.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One could argue that you can't see the far shore because of haze rather than curvature. You could resolve that by observing what you CAN see: at long distances, where you can barely see the far shore, do you just see the top of mountains or tall buildings? Or do you see the whole mountain or building but very hazy? (Okay, I haven't done that experiment, so maybe I'm just a dupe of the round-Earth conspiracy.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, as others have noted, refraction and optical illusions add extra complexity. That's why in general, one experiment is not sufficient to prove or disprove a theory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course there are other ways to demonstrate that the Earth is round. Like, in ancient Egypt, Ptolemy measured the circumference of the Earth by measuring the lengths of shadows at different latitudes.&lt;/p&gt;&#xA;" OwnerUserId="4874" LastActivityDate="2015-11-23T15:17:02.413" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6980" PostTypeId="1" CreationDate="2015-11-23T23:25:34.097" Score="10" ViewCount="313" Body="&lt;p&gt;Last summer, I snuck out with a row boat around 4am. Eventually with the sun risen but still quite low in the horizon, I was rowing in the middle of the absolutely still lake when I witnessed an optical phenomenon unlike anything that I've ever seen before: I found myself enclosed in a triangle in which, the sun was in one corner, and in the other corners, the surface of the lake had turned rainbow-colored. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a photographer I technically understand what happens there, i.e. even though it looked clear to the eye, there obviously must've been some nocturnal mist left on the water surface to act as a medium, and, had there been more moisture particles higher up in the air, I should've seen an entire rainbow connecting these two reflections. But due to the conditions, apparently all I saw was the ends of the rainbow, on their own. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried to search for instances or info on this, but found none. Does this specific phenomenon have a name? Under what conditions might one expect to possibly witness this phenomenon?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a quick illustration of the setting, as perceived subjectively.&#xA;I made a quick simulation of the sun in that time and location using &lt;a href=&quot;http://www.stellarium.org/en&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;Stellarium&quot;&gt;Stellarium&lt;/a&gt; , and the sun was about 11° above the horizon (actual bald horizon, not including trees, hills etc.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TTLSX.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TTLSX.jpg&quot; alt=&quot;setting&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4876" LastEditorUserId="20" LastEditDate="2015-12-16T14:30:38.977" LastActivityDate="2015-12-16T14:30:38.977" Title="Does this optical phenomenon have a name?" Tags="|meteorology|clouds|terminology|light|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="6981" PostTypeId="1" CreationDate="2015-11-24T02:57:44.810" Score="6" ViewCount="370" Body="&lt;p&gt;Recently, I stumbled upon this NASA map of the Earth from the OCO-2, a satellite that measures CO&lt;sub&gt;2&lt;/sub&gt; density in the atmosphere. &lt;a href=&quot;http://www.climatecentral.org/news/nasa-tools-co2-19681&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.climatecentral.org/news/nasa-tools-co2-19681&lt;/a&gt; Specifically, I'm refering to the tool with the CO&lt;sub&gt;2&lt;/sub&gt; heat map with the split-screen slider.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see during the spring, there is less CO&lt;sub&gt;2&lt;/sub&gt; over open ocean and higher CO&lt;sub&gt;2&lt;/sub&gt; over landmasses. During the summer, (by the naked eye) there seems to be a higher CO&lt;sub&gt;2&lt;/sub&gt; density across the path the satellite took. I'm curious the reason for the differences we see.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would expect that during the summer months, when there is a higher density of CO&lt;sub&gt;2&lt;/sub&gt; , that there would be a lower density of CO&lt;sub&gt;2&lt;/sub&gt; because of an overall increase in vegetation. During the spring, there would be more CO&lt;sub&gt;2&lt;/sub&gt; because of a significant decrease in vegetation and increase in energy consumption in the Northern Hemisphere (but not as much as during heavy winter). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Am I making a wrong assumption? What am I missing?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think this is a distinct question from &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2521/why-is-there-a-seasonal-cycle-to-the-amount-of-co2-in-the-atmosphere&quot;&gt;this one&lt;/a&gt; because I'm asking only in the scope of one year or across consecutive seasons.&lt;/p&gt;&#xA;" OwnerUserId="4878" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2020-02-11T22:24:30.127" Title="What causes the counter-intuitive presence of CO2 in the atmosphere during spring and summer months?" Tags="|climate|co2|weather-satellites|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6982" PostTypeId="2" ParentId="6981" CreationDate="2015-11-24T04:19:42.043" Score="7" Body="&lt;p&gt;From &lt;a href=&quot;https://scripps.ucsd.edu/programs/keelingcurve/2013/05/07/why-are-seasonal-co2-fluctuations-strongest-in-northern-latitudes/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scripps&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;[The] latitudinal differences in fluctuation are the result of photosynthetic activity by plants. As plants begin to photosynthesize in the spring and summer, they consume CO&lt;sub&gt;2&lt;/sub&gt; from the atmosphere and eventually use it as a carbon source for growth and reproduction. This causes the decrease in CO&lt;sub&gt;2&lt;/sub&gt; levels that begins every year in May. Once winter arrives, plants save energy by decreasing photosynthesis. Without photosynthesis, the dominant process is the exhalation of CO&lt;sub&gt;2&lt;/sub&gt; by the total ecosystem, including bacteria, plants, and animals.  Two regions of Earth contain the majority of land plants: Northern Hemisphere continents and the tropics that encompass ... the vast rain forests of the Amazon basin. Near the equator, however, the seasonal variations in temperature are less pronounced. Seasonal swings in CO&lt;sub&gt;2&lt;/sub&gt; are therefore most pronounced in the Northern Hemisphere, where the seasonal changes in temperature result in very large differences in plant photosynthesis from summer to winter.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My interpretation of the slide-graphic confirms the idea that more CO&lt;sub&gt;2&lt;/sub&gt; exists earlier in the springtime, especially in the Northern Hemisphere.  There are darker reds (~403 ppb) over most of the northern latitudes in March/April&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1RJq9.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1RJq9.jpg&quot; alt=&quot;OCO in April&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and more of an orange-yellow color in June (~400 ppb).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mg0G2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mg0G2.jpg&quot; alt=&quot;OCO in June&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, I would caution you in putting too much meaning into graphics that NASA develops such as these.  These graphics are made by concatenating a couple weeks of satellite overpass data (generally one to two retrievals per pixel).  These are not an &quot;average&quot; like you might think.  This is because the swath of the instrument detection is very thin, thus requiring weeks to get &quot;global coverage&quot;.  Furthermore, the OCO CO&lt;sub&gt;2&lt;/sub&gt; algorithms are still being refined, and will go through several more revisions before the data is &quot;finalized&quot;.  &lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="725" LastEditDate="2016-09-14T10:43:37.430" LastActivityDate="2016-09-14T10:43:37.430" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6983" PostTypeId="2" ParentId="6975" CreationDate="2015-11-24T15:57:43.300" Score="0" Body="&lt;p&gt;For authoritative answers you should consult the producer of the dataset.  &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;A 5x5 neighborhood sounds like a 25 point sample of values around your gauge.  If you take those values and assume some distribution, the 10th percentile value would be the point on that distribution where 10 percent of the values are smaller than it and 90% are larger.  It isn't clear, however, if they assume a Gaussian distribution or some other distribution.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Take a vertical column above your gauge from the gauge to infinity.  Sample the reflectivity at all heights in that column and report the highest value observed.  Vertical column just means the atmosphere directly above the gauge extending to the top of the atmosphere.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;A radar pulse doesn't measure a point.  The pulse has width and height that it samples.  These dimensions are specified as the distance that the power of the pulse along its centerline is reduced to half.  This is specified as an arc length as the pulse energy spreads out with distance from the radar antenna.  Additionally the pulse has a length and this gives the pulse a depth.  Combined this is the pulse volume and the volume varies with distance from the radar antenna and with characteristics of the radar itself.  You can read more about this in a &lt;a href=&quot;http://www.wdtb.noaa.gov/courses/dloc/topic3/lesson1/Section1/Section1-3.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NWS Weather Decision Training Branch radar training course&lt;/a&gt; (Image below from this site).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GlPLi.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GlPLi.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-11-24T15:57:43.300" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6984" PostTypeId="2" ParentId="6975" CreationDate="2015-11-24T20:00:50.957" Score="1" Body="&lt;p&gt;Here are the answers that I received for anyone interested:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Regarding the question about 10th percentile: The 10th percentile of reflectivity in a 5x5 neighborhood of the gauge means that they take the 25 reflectivity values surrounding the gauge (horizontally), sort them, and return one of the lowest values. The table in the attached image shows an example of this. In this case, the gauge is assumed to be in the green box, and bold value to the bottom right is the 10th percentile value returned by Excel.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Regarding the question about the vertical column: The radar scans at multiple elevation angles (between 0.5 and 19.5 degrees above horizontal), and so each one of those scans will be at a different height when it passes over the location of the gauge, sampling a different set of particles (rain, hail, etc). So the vertical maximum reflectivity at that point is simply taking the maximum value at the gauge location from all the available elevations within a complete set of scans. This “maximum reflectivity in the vertical column” variable is sometimes referred to as “composite reflectivity”.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) Pulse volume refers to the volume of air that is sampled by the radar beam at a given instant. This volume is defined by a horizontal extent, a vertical extent, and a range extent. The horizontal and vertical extents are determined by the characteristics of the antenna and the range being considered. For most radars, this cross-section is circular, since the horizontal and vertical beamwidths are the same, often around 1 degree. The range extent is determined by the amount of time the radar transmits between periods of listening. The physical length of the pulse is the speed of light times the amount of time the pulse is being transmitted, and is typically on the order of a couple hundred meters. The formula for pulse volume is pi(range*vertical beamwidth/2)(rangehorizontal beamwidth/2)(pulse length/2).&lt;/p&gt;&#xA;" OwnerUserId="4870" LastActivityDate="2015-11-24T20:00:50.957" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6985" PostTypeId="1" CreationDate="2015-11-25T11:01:32.847" Score="3" ViewCount="302" Body="&lt;h3&gt;About Tracer Experiment&lt;/h3&gt;&#xA;&lt;p&gt;This experiment is conducted by injecting a fluid with nonreactive species of certain concentration inside a column or core composed of sand. The injection of fluid can either be in the form of a pulse or it can be continuous injection. This type of experiment can be useful to characterize the static and dynamic properties of a subsurface and can help us gain a better understanding of the geology and flow dynamics of the fluid.&lt;/p&gt;&#xA;&lt;h3&gt;Known Information&lt;/h3&gt;&#xA;&lt;p&gt;In this type of experiment we typically know the velocity of the tracer through the column, say &lt;span class=&quot;math-container&quot;&gt;$v$&lt;/span&gt;, the length of the column &lt;span class=&quot;math-container&quot;&gt;$L$&lt;/span&gt;, the injected concentration of the tracer &lt;span class=&quot;math-container&quot;&gt;$C_0$&lt;/span&gt;, a time series of the fluid concentration at the column outlet &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\text{vs.}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt;, which acts as an output data from this experiment.&lt;/p&gt;&#xA;&lt;h3&gt;Questions&lt;/h3&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Which equations are typically used to characterize the flow of&#xA;nonreactive tracer in a porous media at laboratory scale?&lt;/li&gt;&#xA;&lt;li&gt;How can we use the known information to estimate the fluid dispersion coefficient (a measure of fluid velocity variance)?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="4883" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-12-30T01:51:00.460" Title="How to characterize flow of nonreactive tracer in a porous media?" Tags="|hydrology|fluid-dynamics|hydrogeology|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="6987" PostTypeId="2" ParentId="6980" CreationDate="2015-11-25T21:49:22.683" Score="4" Body="&lt;p&gt;It appears from your picture that there is some mist above the lake surface. The phenomenon will be due to the same mechanism that causes conventional rainbows. The angles between the sun, the mist/cloud, and the observer will be identical but you will only see this with the sun low in the sky since the mist is near the water. That will also make the rainbow appear to be floating on the water surface (great photo, btw). I think the dark background of the trees helps make the colours more intense. The low sun means that the spectrum can be seen on either side and behind the observer. So you are correct that it will form a triangle around you. If I'm visualizing things properly, in your photo the sun would be to your right - on the violet side of the rainbow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not aware of any distinct name for this, possibly because it is not really different from a rainbow from a scientific perspective or because too few scientists are awake at 4 AM.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2015-11-25T21:49:22.683" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="6988" PostTypeId="1" AcceptedAnswerId="6998" CreationDate="2015-11-26T08:45:24.293" Score="4" ViewCount="101" Body="&lt;p&gt;This question only pertains to oceans of water and how much they account for the process of creating high winds on a planet with any type of atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="4617" LastEditorUserId="28050" LastEditDate="2015-11-26T12:25:58.623" LastActivityDate="2015-11-28T04:31:09.670" Title="Are oceans a major factor in creating high winds on a planet?" Tags="|meteorology|ocean|planetary-science|wind|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6993" PostTypeId="1" AcceptedAnswerId="6997" CreationDate="2015-11-27T13:27:11.127" Score="5" ViewCount="7554" Body="&lt;p&gt;I know the temperature of a place is determined by various factors, a few of which I can think of are: Altitude, distance from sea, latitude, wind etc. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is basically regarding latitude. If a place is closer to the poles, the temperature would be very low. So if the temperature is low there is a chance that it snows (I do not know what other factors lead to snowfall). But even when the temperature is below 0 in places near poles (Finland) it doesn't snow. But it snows in Germany. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So why there isn't any snow in Finland but in Germany? Does a negative temperature indicate chances of snow?&lt;/p&gt;&#xA;" OwnerUserId="4892" OwnerDisplayName="Vini Vasundharan" LastEditorUserId="4487" LastEditDate="2015-11-28T07:30:15.980" LastActivityDate="2015-11-28T07:30:15.980" Title="Why doesn't it snow even when it is below freezing?" Tags="|meteorology|temperature|precipitation|humidity|snow|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="6994" PostTypeId="1" AcceptedAnswerId="6996" CreationDate="2015-11-27T16:44:03.793" Score="6" ViewCount="345" Body="&lt;p&gt;Looking at the &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_magnetic_field&quot; rel=&quot;nofollow&quot;&gt;wikipedia article on the Earth's magnetic field&lt;/a&gt;, I see that its strength varies through time. How did Earth's magnetic field change throughout its history, from the beginning of the Archean period (~4 billions years ago) to today?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;My current attempt&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All I found so far is &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/9/9f/Brunhes_geomagnetism_western_US.png&quot; rel=&quot;nofollow&quot;&gt;this graph&lt;/a&gt; from wikipedia (which is on a too short time scale) and &lt;a href=&quot;http://www.rochester.edu/news/show.php?id=2842&quot; rel=&quot;nofollow&quot;&gt;this kind of text&lt;/a&gt; (not a science paper) reporting an estimate for a given time point (3.2 billions years ago) reporting a field of about 25 microTeslas.&lt;/p&gt;&#xA;" OwnerUserId="4895" LastEditorUserId="543" LastEditDate="2015-12-01T07:43:31.180" LastActivityDate="2015-12-01T07:43:31.180" Title="How did the intensity of Earth's magnetic field change through geological time?" Tags="|geophysics|earth-history|geomagnetism|paleomagnetism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6995" PostTypeId="2" ParentId="2888" CreationDate="2015-11-27T18:34:19.003" Score="1" Body="&lt;p&gt;Kimberlite is often associated with failed rifts which provide a way for the magma to reach the surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the association of diamond and old cratons, you must understand that diamonds require special conditions of pressure and temperature. As you go down in the mantle the pressure rises and the temperature rises accordingly but to form and be preserved diamonds require a high pressure but a lower temperature than that normally associated with such pressure. Old cratons have thick and cold lithospheric roots that sometime open a window of diamond stability with the right pressure and temperature. &lt;/p&gt;&#xA;" OwnerUserId="4896" LastActivityDate="2015-11-27T18:34:19.003" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6996" PostTypeId="2" ParentId="6994" CreationDate="2015-11-27T20:10:09.910" Score="3" Body="&lt;p&gt;The Earth's initial accretion was about 4.5 billion years ago, and there is good Hf-W isotopic evidence that an iron core started to form within about 10 M years, and may have been largely complete within 30 M years. However, the Earth's dynamo, which is driven by isotopic heating and core rotation/convection, didn't switch on strait away. It must have built up over hundreds of millions of years, possibly kick-started by a the magnetic field of a stronger solar wind at that time. The evidence from 3.5 Bn year old dacites suggest that the magnetic field at that time was only 30 to 50% of the current value. There is no magnetic data for 4.4 to 3.5 Bn years, (the time period you are interested in), but current models lean towards lower rather than higher values. There appears to be no mechanism for strong magnetism in the early Earth. Geomagnetic evidence from about 2.5 Bn years ago seems to indicate that the Earths magnetism was more stable then than now, with few if any peaks of high or low magnetism. Probably the Earth's early magnetic field will always be imprecisely known because nearly all the early rocks have been 'cooked' in such a way as to extinguish the early magnetic evidence.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-11-27T20:10:09.910" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="6997" PostTypeId="2" ParentId="6993" CreationDate="2015-11-27T20:33:46.637" Score="6" Body="&lt;p&gt;Farrenthorpe is right, a little surfing the net for snow distribution would clarify the picture for you. However, I think you are referring to certain times when it rains further north and snows further south. There are several reasons for local anomalies, of which the most important is the dynamics of the polar jet streams. These are strong high-altitude wind that blow constantly in both hemispheres. These winds have meanders which migrate around the world, as depicted in:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yjcOp.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yjcOp.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.google.com/search?q=jet+stream++image+OR+picture+OR+diagram&amp;amp;lr=&amp;amp;as_qdr=all&amp;amp;tbm=isch&amp;amp;tbo=u&amp;amp;source=univ&amp;amp;sa=X&amp;amp;ved=0ahUKEwiX44v3tbHJAhUEjywKHSncCP4Q7AkINA&amp;amp;biw=1352&amp;amp;bih=631#imgrc=LXFiBx8qaJg5xM%3A&quot; rel=&quot;noreferrer&quot;&gt;https://www.google.com/search?q=jet+stream++image+OR+picture+OR+diagram&amp;amp;lr=&amp;amp;as_qdr=all&amp;amp;tbm=isch&amp;amp;tbo=u&amp;amp;source=univ&amp;amp;sa=X&amp;amp;ved=0ahUKEwiX44v3tbHJAhUEjywKHSncCP4Q7AkINA&amp;amp;biw=1352&amp;amp;bih=631#imgrc=LXFiBx8qaJg5xM%3A&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meanders in these polar jets pretty much control the mid- to high latitude weather within the troposphere, bringing bulges of Arctic air south, and counter bulges of warm mid-latitude air to further north. But then they move on, and the reverse conditions sometimes prevail. As a long-term average the latitudinal control on snow distribution dominates. Of course, there are other influences as well, mainly related to heat re-distribution by the great ocean currents.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-11-27T20:33:46.637" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="6998" PostTypeId="2" ParentId="6988" CreationDate="2015-11-27T20:48:34.610" Score="3" Body="&lt;p&gt;The major factor is not the size or temperature of the ocean, it is the &lt;em&gt;differential&lt;/em&gt; temperatures, and hence large scale convection, such as Hadley cells, Monsoons and tropical storms. With the latter, large oceans are relatively deep with thin warm water over vastly deeper cold water. The minimum temperature for as hurricane to form is about $27^\circ\!$C ($80^\circ\!$F), which most commonly develops over relatively shallow water, or where there is a massive influx of warm water such as the current El Niño. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4487" LastEditDate="2015-11-28T04:31:09.670" LastActivityDate="2015-11-28T04:31:09.670" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="6999" PostTypeId="2" ParentId="6993" CreationDate="2015-11-28T04:28:07.447" Score="3" Body="&lt;p&gt;Gordon has an excellent answer to one version of your Q. In case you are asking a more basic Q, here is a try at an answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Vini, think about the monsoons. Cooling the soggy parcel of air causes rain, but continued gradual cooling as it crosses an area of land does not &lt;strong&gt;&lt;em&gt;necessarily&lt;/em&gt;&lt;/strong&gt; create even heavier rain (leaving aside the rapid cooling that happens when it is pushed up a mountain). The parcel is dried out as it cools, so by the time it hits higher cooler land, it does not have that much precipitation to give.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/euKdc.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/euKdc.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Snow is just another type of precipitation. Like with rain, it occurs when somewhere in the air column the relative humidity humidity goes over 100% and the is at least some dust for nucleation. The history of the air matters. That very cold air in Norway had to travel there from somewhere warmer and more humid, perhaps even through Germany. As it traveled to Finland, it became colder and produced snow, drying it out, so by the time it got there it had very little water vapor to turn into snow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pciTv.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pciTv.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact, we have a saying here where I am in Minnesota (USA) that it can be &lt;a href=&quot;http://www.weatherimagery.com/blog/too-cold-to-snow/&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;too cold to snow&quot;&lt;/a&gt;. Our greatest snowfall is in March, early spring, when temps are right around freezing. It snow very very little in central Antarctica, the coldest part of the Earth.&lt;/p&gt;&#xA;" OwnerUserId="4487" LastEditorUserId="4487" LastEditDate="2015-11-28T04:45:59.157" LastActivityDate="2015-11-28T04:45:59.157" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7003" PostTypeId="2" ParentId="6985" CreationDate="2015-11-29T23:43:18.207" Score="3" Body="&lt;h2&gt;Governing Equation&lt;/h2&gt;&#xA;&lt;p&gt;The constitute equation for a nonreactive tracer test is governed by fluid flow due to advection (viscous flow) and fluid flow due to diffusion. The partial differential equation that governs this process is given as:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial C}{\partial t} + \nabla.\left(v  C - D\nabla{C} \right)=0$$&lt;/span&gt;&#xA;Where, &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; is concentration of the tracer in space &lt;span class=&quot;math-container&quot;&gt;$(x,y,z)$&lt;/span&gt; and time &lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt;; &lt;span class=&quot;math-container&quot;&gt;$v$&lt;/span&gt; is the velocity of the injected tracer fluid, and &lt;span class=&quot;math-container&quot;&gt;$D$&lt;/span&gt; is the dispersion coefficient.&lt;/p&gt;&#xA;&lt;h2&gt;1-Dimensional Example&lt;/h2&gt;&#xA;&lt;p&gt;Let's consider a following 1-dimensional core in which tracer is injected at left hand side face (point B) as a heavyside unit step function. The output tracer concentration profile is observed at right hand side face (point A):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LEL3O.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LEL3O.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The boundary conditions for this general scenario are given as follow:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\overline C_B=0, x&amp;gt;0, t=0$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\overline C_B=1, x=0, t&amp;gt;=0$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\overline C_B=0, x\rightarrow\infty, t&amp;gt;=0$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now, there exists an analytical solution for this 1-dimensional example that can give you tracer concentration at any place within the column, say &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt;, at any time, say &lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt;. That is, we can estimate &lt;span class=&quot;math-container&quot;&gt;$C(x,t)$&lt;/span&gt; using the following analytical solution:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\overline C_B=\frac{1}{2}\left[1-{erf}\left(\frac{x-vt}{2\sqrt{Dt}}\right)\right]$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where, &lt;span class=&quot;math-container&quot;&gt;$v$&lt;/span&gt; is the fluid velocity which is known and &lt;span class=&quot;math-container&quot;&gt;$D$&lt;/span&gt; is the fluid dispersion coefficient which is unknown.&lt;/p&gt;&#xA;&lt;h2&gt;How to Estimate Dispersion Coefficient&lt;/h2&gt;&#xA;&lt;p&gt;One of the data that we obtain from tracer experiment is the tracer concentration with time at the column output (point A), which is also referred to as effluent concentration. Let's call this data as &lt;span class=&quot;math-container&quot;&gt;$C_{measured}$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Similarly, using the above analytical function, we would estimate the tracer effluent concentration (at &lt;span class=&quot;math-container&quot;&gt;$x=L$&lt;/span&gt;) by guessing some value of dispersion coefficient &lt;span class=&quot;math-container&quot;&gt;$D$&lt;/span&gt;. However, since this &lt;span class=&quot;math-container&quot;&gt;$D$&lt;/span&gt; is just a guess, so the estimated effluent concentration using the formula is not correct. The correct effluent concentration is the one we have measured i.e .&lt;span class=&quot;math-container&quot;&gt;$C_{measured}$&lt;/span&gt;. You would have guessed by now that we use the measured concentration in the analytical expression to estimate &lt;span class=&quot;math-container&quot;&gt;$D$&lt;/span&gt;, and the appropriate way of doing this is by devising an objective function and minimizing its square as follow:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$f_{obj}=min\left[\sum (C_{measured}-C_{calculated})^2\right]$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;So you find &lt;span class=&quot;math-container&quot;&gt;$C_{calculated}$&lt;/span&gt; using multiple guesses of &lt;span class=&quot;math-container&quot;&gt;$D$&lt;/span&gt; and stop the iteration for that particular &lt;span class=&quot;math-container&quot;&gt;$D$&lt;/span&gt; which gives you minimum &lt;span class=&quot;math-container&quot;&gt;$f_{obj}$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user3153" LastEditorUserId="-1" LastEditorDisplayName="user3153" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-11-30T00:48:45.407" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7006" PostTypeId="1" CreationDate="2015-12-01T17:16:53.040" Score="1" ViewCount="149" Body="&lt;p&gt;I have transient model with domain 200*200m and consists of 5 layers with 45 stress period, first layer is alluvium and the other 4 layers are weathered rock will be solved using traditional MODFLOW GMS.&#xA;&lt;br&gt; The domain is restricted by head boundaries &quot;head drop&quot;, when I check for simulation, the model gives some errors for cells at boundaries for the first layer, because of the head drop gives elevation lower than the first layer bottom elevation, &#xA;&lt;br&gt; for example ( (for particular cell at transient boundary in the first layer)&lt;br&gt;cell top elevation = 500m and lower elevation is 490m and the transient head is linear starting from 498 to 450 over the 45 stress period&#xA;&lt;br&gt; when trying to attempt a run with head drop lower than the bottom elevation (as previously illustrated) of the first layer cells, the model can't complete all stress periods and stop running&#xA;&lt;br&gt;&#xA;how can I solve this problem as I have to maintain the same head drop??&#xA;&lt;br&gt; any help&lt;/p&gt;&#xA;" OwnerUserId="4908" LastActivityDate="2015-12-01T17:16:53.040" Title="Groundwater &quot;GMS-MODFLOW&quot; Transient Model" Tags="|groundwater|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7007" PostTypeId="1" AcceptedAnswerId="7008" CreationDate="2015-12-01T21:11:22.230" Score="4" ViewCount="998" Body="&lt;p&gt;I am brewing on an idea where instead of cursing and throwing all our physical junk mail in the paper recycling bin, we process it into pellets to be burned in our fireplace as free fuel.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Before I start I would like to run the numbers but I am having a hard time finding the actual effect of burning said paper.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://chimneysweeponline.com/howood.htm&quot; rel=&quot;nofollow&quot;&gt;this&lt;/a&gt; page regular birch firewood will burn at 14 million BTU per cubic meter (20 per chord). What is the comparable amount for waste paper?&lt;/p&gt;&#xA;" OwnerUserId="4911" LastEditorUserId="725" LastEditDate="2016-09-14T10:39:09.780" LastActivityDate="2018-11-21T01:02:40.823" Title="How many BTU per cubic meter does typical paper waste yield when burned in a modern domestic fireplace" Tags="|environmental-protection|resources|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7008" PostTypeId="2" ParentId="7007" CreationDate="2015-12-02T01:03:10.640" Score="3" Body="&lt;p&gt;&lt;strong&gt;About 12 million BTU, or 3.5 MWh.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I searched for &lt;a href=&quot;https://www.google.ca/search?q=paper+btu&amp;amp;oq=paper+btu&amp;amp;aqs=chrome.0.69i59j69i60.982j0j1&amp;amp;sourceid=chrome&amp;amp;es_sm=91&amp;amp;ie=UTF-8&quot; rel=&quot;nofollow&quot;&gt;&lt;em&gt;paper btu&lt;/em&gt;&lt;/a&gt; and got &lt;a href=&quot;http://www.balboa-pacific.com/WasteToEnergy/BTU_Values.pdf&quot; rel=&quot;nofollow&quot;&gt;loads&lt;/a&gt;... &lt;a href=&quot;http://infohouse.p2ric.org/ref/11/10059.pdf&quot; rel=&quot;nofollow&quot;&gt;of&lt;/a&gt;... &lt;a href=&quot;http://msw.cecs.ucf.edu/EnergyProblem.pdf&quot; rel=&quot;nofollow&quot;&gt;hits&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seems like 7000 BTU/lb is a decent starting point, or $1.6 \times 10^7\ \mathrm{J/kg}$. If we say a ream of letter-size paper weighs about 5 lb, then we can calculate that paper yields about &lt;a href=&quot;http://www.wolframalpha.com/input/?i=2.25+kg+*+%281+m%5E3+%2F+%288.5+in+*+11+in+*+2+in%29%29+*+1.7*10%5E7+J%2Fkg&quot; rel=&quot;nofollow&quot;&gt;$1.2 \times 10^{10}\ \mathrm{J/m^3}$&lt;/a&gt; when burned — enough to heat the average US house for 15 weeks.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2015-12-02T12:36:37.817" LastActivityDate="2015-12-02T12:36:37.817" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7009" PostTypeId="1" AcceptedAnswerId="7021" CreationDate="2015-12-02T01:45:10.330" Score="2" ViewCount="66" Body="&lt;p&gt;I'm interested in understanding how meteorology works in Canada (esp. from an Open Data perspective). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can someone explain, or provide resources, that indicates an &lt;strong&gt;overview&lt;/strong&gt; of the actors involved on the spectrum from &lt;em&gt;initial data measurement&lt;/em&gt; through to the &lt;em&gt;weatherperson on the TV screen&lt;/em&gt;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My main concern is to understand if data is made freely available, but I am also interested in the various players and their position in the public/private sector. (I feel that this is relatively well documented for the USA, but I can't find the story in Canada).&lt;/p&gt;&#xA;" OwnerUserId="4913" LastActivityDate="2015-12-03T00:31:42.967" Title="Meteorology in Canada" Tags="|meteorology|canada|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7010" PostTypeId="1" AcceptedAnswerId="7018" CreationDate="2015-12-02T06:24:37.787" Score="4" ViewCount="557" Body="&lt;p&gt;Humans depend on $\ce{O2}$ for breathing. The source of $\ce{O2}$ is photosynthesis by plants or cyanobacteria in the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How is it, that when people travel through deserts or the Arctic / Antarctica, they able to breathe? Is it due to Earth's wind currents blowing $\ce{O2}$ from the nearest ocean?&lt;/p&gt;&#xA;" OwnerUserId="4914" LastEditorUserId="543" LastEditDate="2015-12-02T22:33:44.720" LastActivityDate="2015-12-02T23:55:52.723" Title="How is there enough $\ce{O2}$ in the atmosphere to breathe if you are in a desert with no plants?" Tags="|atmosphere|wind|atmospheric-circulation|atmospheric-chemistry|oxygen|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7011" PostTypeId="1" CreationDate="2015-12-02T06:46:46.873" Score="3" ViewCount="189" Body="&lt;p&gt;Is there a meaningful way to delimit a mountain as an area with a sharp boundary? Looked as as a 2D shape on the datum it would be a footprint of the mountain similar to a building footprint, while as a region cut out of the surface it would delimit the surface of the mountain from surface that is not port of the mountain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously there's going to be some degree to which this is arbitrary but it seems like some function of slope, aspect, elevation etc ought to be able to produce some meaningful partition of the earth's surface.   I would like to know if any concept like this is used at all, how it's defined, and how well it corresponds with the intuitive sense of one point being part of a mountain, another point being part of a different mountain, and a third point not being part of any mountain.  If it's just completely unworkable despite the intuitive appeal, then a reasonable explanation of why is an acceptable answer.&lt;/p&gt;&#xA;" OwnerUserId="582" LastActivityDate="2015-12-02T15:35:56.697" Title="Is there a meaningful concept of a mountain having a footprint area?" Tags="|mountains|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7012" PostTypeId="1" AcceptedAnswerId="7020" CreationDate="2015-12-02T08:07:22.227" Score="12" ViewCount="7530" Body="&lt;p&gt;I'm trying to plot wind barbs in basemap and I have two separate netCDF files.&#xA;Here is what I am trying to produce, or something like it:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/G9XEA.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G9XEA.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;How do I read a uwnd variable in a netCDF file in python?&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;from mpl_toolkits.basemap import Basemap&#xA;from netCDF4 import Dataset, date2index&#xA;import numpy as np&#xA;import matplotlib.pyplot as plt&#xA;from datetime import datetime&#xA;from IPython.display import Image&#xA;from IPython.core.display import HTML &#xA;import netCDF4 as nc&#xA;plt.clf()&#xA;nc_file = '042711_V.nc'&#xA;nc_file2 = '042711_U.nc'&#xA;V = Dataset(nc_file, mode='r')&#xA;U = Dataset(nc_file2, mode='r')&#xA;print U.variables&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;This verifies that uwnd is indeed a variable, but why won't it read?&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;OrderedDict([(u'lat', &amp;lt;type 'netCDF4._netCDF4.Variable'&amp;gt;&#xA;float32 lat(lat)&#xA;    units: degrees_north&#xA;    actual_range: [ 90. -90.]&#xA;    long_name: Latitude&#xA;unlimited dimensions: &#xA;current shape = (73,)&#xA;filling off&#xA;), (u'lon', &amp;lt;type 'netCDF4._netCDF4.Variable'&amp;gt;&#xA;float32 lon(lon)&#xA;    units: degrees_east&#xA;    long_name: Longitude&#xA;    actual_range: [   0.   357.5]&#xA;unlimited dimensions: &#xA;current shape = (144,)&#xA;filling off&#xA;), (u'time', &amp;lt;type 'netCDF4._netCDF4.Variable'&amp;gt;&#xA;float64 time(time)&#xA;    units: hours since 1800-1-1 00:00:0.0&#xA;    long_name: Time&#xA;    actual_range: [ 71870952.  71870952.]&#xA;    delta_t: 0000-01-00 00:00:00&#xA;unlimited dimensions: time&#xA;current shape = (1,)&#xA;filling off&#xA;), (u'uwnd', &amp;lt;type 'netCDF4._netCDF4.Variable'&amp;gt;&#xA;float32 uwnd(time, lat, lon)&#xA;    long_name: u wind&#xA;    valid_range: [-99999.  99999.]&#xA;    actual_range: [ -26.84999084  377.20001221]&#xA;    units: m/s&#xA;    add_offset: 0.0&#xA;    scale_factor: 1.0&#xA;    missing_value: -9.96921e+36&#xA;    precision: 99&#xA;    least_significant_digit: 99&#xA;    var_desc: u wind&#xA;    dataset: CDC Derived NCEP Reanalysis Products&#xA;    level_desc:  500mb Pressure Level&#xA;    statistic: Composite&#xA;    parent_stat: Other&#xA;unlimited dimensions: time&#xA;current shape = (1, 73, 144)&#xA;filling off&#xA;)])&#xA;&#xA;KeyError: 'uwnd'&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;I'm trying to plot some widnbarbs on the map. i have successfully gotten it to read the time, longitude, and latitude, bu what does the uwnd mean and how do I read it into the numpy format?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is the site I found on how to read netCDF files:&#xA;&lt;a href=&quot;http://www.hydro.washington.edu/~jhamman/hydro-logic/blog/2013/10/12/plot-netcdf-data/&quot; rel=&quot;noreferrer&quot;&gt;http://www.hydro.washington.edu/~jhamman/hydro-logic/blog/2013/10/12/plot-netcdf-data/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3120" LastEditorUserId="2536" LastEditDate="2017-06-04T11:57:32.937" LastActivityDate="2017-07-30T11:02:33.070" Title="Plotting wind barbs in python" Tags="|meteorology|wind|visualization|netcdf|python|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7015" PostTypeId="1" CreationDate="2015-12-02T13:30:26.253" Score="2" ViewCount="140" Body="&lt;p&gt;A recent &lt;a href=&quot;https://www.newscientist.com/article/dn28595-massive-el-nino-sweeping-globe-is-now-the-biggest-ever-recorded&quot; rel=&quot;nofollow&quot;&gt;article&lt;/a&gt; in New Scientist reports the following claim made by Wenju Cai at CSIRO Melbourne.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Southern India is having a lot of rain as it goes into winter, having&#xA;  come out of the dry monsoon. This is only so during extreme El Niño,&#xA;  so it is a confirmation that the El Niño is huge&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Does the claim indicate that a strong El Nino has a causal effect in extreme rainfalls in delayed monsoons? Has there been any historical evidence to backup this claim (for example the 1997-98 El Nino data)&lt;/p&gt;&#xA;" OwnerUserId="4917" LastActivityDate="2015-12-02T13:30:26.253" Title="Correlation of El Nino and south indian monsoon" Tags="|meteorology|climate|climate-change|rainfall|monsoon|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7016" PostTypeId="2" ParentId="7010" CreationDate="2015-12-02T15:25:56.573" Score="2" Body="&lt;p&gt;Look at it this way: According to the American National Center of Atmospheric research, the Earths atmosphere weighs 5.148 x 10^^18 kg., and that atmosphere is composed of about 20.8 to 20.9% oxygen (depending on moisture content of the air). So the Earths atmosphere contains about 1.07 million trillion kgs of oxygen. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The 7.5 billion (or so) humans on the planet, each converts an average of about 0.73 kg of oxygen per day, converting most of it to exhaled CO2. So the planetary consumption of oxygen by humans, as a percentage of the total available, is about 100 x 0.73 x 10^^9 / 1.07 x 10^^18 %.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is, about half of one millionth of 1% of the Earths available oxygen, a level of oxygen deficiency that is almost instantly dispelled by turbulent mixing in the troposphere (i.e.by 'weather'). So no, there is no chance of gasping for oxygen in deserts or polar wastes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now gasping for air 8000 metres up a mountain, or in a crowded disco with cigarette smoke and poor ventilation - that is another question!&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-12-02T15:25:56.573" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7017" PostTypeId="2" ParentId="7011" CreationDate="2015-12-02T15:35:56.697" Score="1" Body="&lt;p&gt;The mountain you see is only a part of the story. From a geological view all mountains have roots, in which the weight of the mountain depresses the upper crust into the lower crust (occasionally with gravity inversion, as in salt diapirs), and the overall crust is depressed into the upper mantle. This results in a regional gravity anomaly which could be regarded as one form of the mountain footprint. That is, a map of the deviation of the mountain's 'Bouguer anomaly', away from the regional gravitational envelope.&#xA;But that's just a geophysical perspective. You could doubtless develop comparable 'footprint definitions' from a hydrologic or geomorphologic perspective. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-12-02T15:35:56.697" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7018" PostTypeId="2" ParentId="7010" CreationDate="2015-12-02T21:56:04.863" Score="2" Body="&lt;p&gt;The short answer is, $\ce{O2}$ is all around us!  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You aren't breathing the $\ce{O2}$ that the trees next to you are respirating (at least not much).  No matter which way the wind is blowing, you will have sufficient oxygen content.  A &quot;can't breathe&quot; feeling comes from inhaling pollutants or extremely dry air (in which case you need to drink more water).  Unless, of course, you are so far up in the atmosphere that there is simply less atmosphere to breathe (e.g. lower atmospheric pressure).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see in the image below, the $\ce{O2}$ molecule abundance in the atmosphere is a giant reservoir that extends far up into the atmosphere.  $\ce{O2}$ and $\ce{N2}$ are evenly mixed throughout the entire atmosphere, even beyond the stratosphere.  Thus, the abundance of oxygen in the lower atmosphere is not really a local phenomenon.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of the free oxygen available is due to ancient oceanic phytoplankton, and they are still producing!  While there are fluctuations in the oxygen abundance of the atmosphere on a geological time scale, there is no shortage of $\ce{O2}$ since there is an overwhelming amount of production.&lt;br&gt;&#xA;For a quantitative breakdown of the oxygen production/consumption, see &lt;a href=&quot;https://en.wikipedia.org/wiki/Oxygen_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Oxygen_cycle&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Zvdhj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Zvdhj.jpg&quot; alt=&quot;Vertical profiles of the mixing ratios of selected species at the equinox (from Goody and Yung, 1989).&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;   ****Vertical profiles of the mixing ratios of selected species at the equinox**** &#xA;&#xA;   R. M. Goody and Y.L. Yung, Atmospheric Radiation, Theoretical Basis, OUP, 1989.&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;This wikipedia article has a great discussion of the topic: &lt;a href=&quot;https://en.wikipedia.org/wiki/Geological_history_of_oxygen&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Geological_history_of_oxygen&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Before photosynthesis evolved, Earth's atmosphere had no free $\ce{O2}$.  Photosynthetic prokaryotic organisms that produced $\ce{O2}$ as a waste product lived long before the first build-up of free oxygen in the atmosphere, perhaps as early as 3.5 billion years ago. The oxygen they produced would have been rapidly removed from the atmosphere by weathering of reducing minerals, most notably iron. This 'mass rusting' led to the deposition of iron oxide on the ocean floor, forming banded iron formations. Oxygen only began to persist in the atmosphere in small quantities about 50 million years before the start of the Great Oxygenation Event. This mass oxygenation of the atmosphere resulted in rapid buildup of free oxygen. At current rates of primary production, today's concentration of oxygen could be produced by photosynthetic organisms in 2,000 years. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Since the start of the Cambrian period, atmospheric oxygen concentrations have fluctuated between 15% and 35% of atmospheric volume. The maximum of 35% was reached towards the end of the Carboniferous period (about 300 million years ago), a peak which may have contributed to the large size of insects and amphibians at that time.  Whilst human activities, such as the burning of fossil fuels, have an impact on relative carbon dioxide concentrations, their impact on the much larger concentration of oxygen is less significant.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2015-12-02T23:55:52.723" LastActivityDate="2015-12-02T23:55:52.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7019" PostTypeId="1" CreationDate="2015-12-02T23:54:30.097" Score="3" ViewCount="160" Body="&lt;p&gt;In a 3-component Sp RF I have the green's function in P,SV, and SH. The actual component to the RF that shows the Sp conversion (the one always published in the literature), which would represent as a negative phase around the LAB and a big positive one over the Moho, would have to be the P component...right? I have three components to these RFs, but they were never labeled, two of them have the zero lag arrival at the same exact time while the third has its zero lag arrival occur about 3 seconds before the other two. Remember this is an Sp RF! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an S wave in an non-isotropic (i.e. Earth) media would have some level of energy in two components, SV and SH (albeit the SH is always a lower SNR given the Earth is not actually isotropic), it completely makes sense that the two components in the receiver function that happen to have the zero lag direct arrival of the wave at the EXACT same time would have to be the SV and SH components. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given that one of these two has a much lower SNR I could also argue which one is SV and which one is SH. Furthermore, since the only remaining component has its direct arrival occur BEFORE the other two I should naturally conclude this to be the P component! ....but this is where it gets complicated....this supposed P component does not have a clear positive spike where the Moho should be and a clear negative spike where the LAB should be.....the supposed SV component does....&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I feel like I am just standing at the door before I walk in and learn an incredibly powerful lesson about the Earth, but I also feel like I want someone to walk through with me and tell me I'm on the right track in terms of my thinking....so am I??&lt;/p&gt;&#xA;" OwnerUserId="4921" LastEditorUserId="4921" LastEditDate="2015-12-03T00:46:31.627" LastActivityDate="2015-12-03T13:39:02.950" Title="Which component in a 3-component Sp receiver function is the actual Sp RF?" Tags="|geophysics|seismology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7020" PostTypeId="2" ParentId="7012" CreationDate="2015-12-03T00:15:28.340" Score="14" Body="&lt;p&gt;Your &lt;code&gt;uwnd&lt;/code&gt; variable holds 32 bit floats and has shape (1,73,144) corresponding to time, lat, lon and is located in the &lt;code&gt;Dataset&lt;/code&gt; you have called 'U'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One way to put this in a numpy array is:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;uwind = np.zeros((lat,lon), np.float)&#xA;uwind = U.variables['uwnd'][1,:,:]&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The first line sets the size of the uwind array, which is helpful from a performance standpoint and the second loads the data from time &lt;code&gt;1&lt;/code&gt; into the array.  &lt;code&gt;lat&lt;/code&gt; and &lt;code&gt;lon&lt;/code&gt; above are your grid dimensions 73 and 144 and &lt;code&gt;np&lt;/code&gt; is the &lt;code&gt;numpy&lt;/code&gt; module.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The u wind is just the east-west component of the wind.  The north-south component will be in the v wind variable.  You will need both to plot the wind.  To plot the barbs you will need to setup arrays for your x and y coordinates which will depend on lat,lon and possibly your map projection.  once you have an &lt;code&gt;x&lt;/code&gt; and &lt;code&gt;y&lt;/code&gt; array as well as &lt;code&gt;uwind&lt;/code&gt; and &lt;code&gt;vwind&lt;/code&gt; you can plot the wind barbs using matplotlib as:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;plt.barbs(x, y, u, v)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;and can &lt;a href=&quot;http://matplotlib.org/examples/pylab_examples/barb_demo.html&quot;&gt;customize their look with various options&lt;/a&gt;. The &lt;code&gt;plt&lt;/code&gt; reference is the &lt;code&gt;matplotlib.pyplot&lt;/code&gt; module.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For further reading, here are &lt;a href=&quot;http://schubert.atmos.colostate.edu/~cslocum/netcdf_example.html&quot;&gt;some examples of plotting netcdf data&lt;/a&gt; from a friend of mine at CSU.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2015-12-03T01:43:51.387" LastActivityDate="2015-12-03T01:43:51.387" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7021" PostTypeId="2" ParentId="7009" CreationDate="2015-12-03T00:31:42.967" Score="4" Body="&lt;p&gt;Canada is fairly similar to the US in how this works.  As pointed out in a comment, Environment Canada is the primary provider of observation and forecast data within Canada.  You can &lt;a href=&quot;https://weather.gc.ca/mainmenu/modelling_menu_e.html&quot; rel=&quot;nofollow&quot;&gt;access plots of this data&lt;/a&gt; and somewhere on that site you can probably also get access to the raw data files to process on your own.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Canada also partners with other states to provide data globally that others can use, some of which provide global model products such as ECMWF and NOAA.  The data from the Euro is not completely open but the data from the GFS is freely available.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The person on TV is working with their fellow station meteorologists and often under a chief meteorologist.  They are going to look at data provided by Environment Canada observations and model output, global model data from others and perhaps private sector weather provider companies who themselves ingest all of that data and have operational meteorologists on staff.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The general flows of data will be&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Observations taken by Environment Canada are ingested&lt;/li&gt;&#xA;&lt;li&gt;Data is shared with other weather agencies, Canada ingests global weather from others&lt;/li&gt;&#xA;&lt;li&gt;EC runs forecast models&lt;/li&gt;&#xA;&lt;li&gt;EC makes observational and model data available &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Private sector companies may use a workflow like:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Ingest data from government sources&lt;/li&gt;&#xA;&lt;li&gt;Process data, run models, make forecasts&lt;/li&gt;&#xA;&lt;li&gt;Make that data available to clients&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;TV stations will have a flow like:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Ingest data from EC, global models and possibly private sector companies&lt;/li&gt;&#xA;&lt;li&gt;Interpret data and make local forecasts&lt;/li&gt;&#xA;&lt;li&gt;Present forecasts to the public.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-12-03T00:31:42.967" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7022" PostTypeId="2" ParentId="7019" CreationDate="2015-12-03T13:39:02.950" Score="1" Body="&lt;p&gt;I am not sure I clearly understand the question, but here is a quote from the paper that I looked at a while ago about S Receiver Functions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From: Yuan, Xiaohui, Rainer Kind, Xueqing Li, and Rongjiang Wang. &quot; The S Receiver Functions: Synthetics and Data Example .&quot; Geophysical Journal International 165.2 (May, 2006): 555-564:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Here we briefly summarize the processing steps for generating S receiver functions. The ZNE-component seismograms of S and SKS waves are rotated firstly into the ZRT system with the back azimuth determined by locations of the receiver and earthquake. The ZRT components are further ro-tated into the P-SV-SH system with the incidence angle determined by minimizing the amplitudes at time of S/SKS arrival on the P component. Waveforms are visually selected to avoid the confusing of S and SKS phases. Data with strong interference of S and SKS are excluded. A window of S/SKS waves on the SV component is deconvolved from the P component for source equalization. For direct comparison with the P receiver functions, we need to reverse the time axis as well as the amplitudes of the S receiver functions.Move-out correction is then applied for all the PRFs, SRFs and SKSRFs, with a reference slowness of 6.4 s deg−1 and the IASP91 model as reference.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does this help? &lt;/p&gt;&#xA;" OwnerUserId="4924" LastActivityDate="2015-12-03T13:39:02.950" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7025" PostTypeId="1" AcceptedAnswerId="7026" CreationDate="2015-12-04T10:13:52.597" Score="7" ViewCount="1419" Body="&lt;p&gt;What does it mean when I say &quot;the wind direction is 50&lt;sup&gt;o&lt;/sup&gt;&quot; on a UTM map? Which direction is the 0&lt;sup&gt;o&lt;/sup&gt; reference?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, if I draw a wind vector &lt;code&gt;V&lt;/code&gt; as seen in the image below, what degrees does it correspond to for the UTM map?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RnISB.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RnISB.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4929" LastActivityDate="2015-12-08T00:29:40.747" Title="How do I represent wind direction on a UTM (Universal Transverse Mercator) map projection?" Tags="|meteorology|measurements|wind|geography|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7026" PostTypeId="2" ParentId="7025" CreationDate="2015-12-04T14:08:06.943" Score="6" Body="&lt;p&gt;Meteorological winds are referenced from North being 0$^{\circ}$ increasing in a clockwise direction.  Additionally, they are named for the direction the wind is coming from.  Your vector on the map, which is mathematically 45$^{\circ}$ is meteorologically 225$^{\circ}$ aka a southwesterly wind.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A 0$^{\circ}$ wind is a wind from the north (math vector 270$^{\circ}$).  &lt;/li&gt;&#xA;&lt;li&gt;A 180$^{\circ}$ wind is wind from the south (math vector 90$^{\circ}$).&lt;/li&gt;&#xA;&lt;li&gt;A 50$^{\circ}$ wind is from the northeast (math vector 220$^{\circ}$).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In general if $\alpha$ is the mathematical angle and $\beta$ is the meteorological angle, then the relation between the two conventions is given by $$\alpha = 270^{\circ} - \beta$$ where angles are specified in degrees.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vfez7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vfez7.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sub&gt;Image from &lt;a href=&quot;https://www.e-education.psu.edu/meteo300/node/719&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.e-education.psu.edu/meteo300/node/719&lt;/a&gt; from Penn State available under CC-by-nc-sa-3.0&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-12-04T14:08:06.943" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7027" PostTypeId="1" AcceptedAnswerId="7030" CreationDate="2015-12-04T15:31:55.163" Score="7" ViewCount="2969" Body="&lt;p&gt;Taiga is the Russian word for big areas of forest wilderness in high latitude regions. What about forests in the mountains? What is the name for the forested areas in mountains which are below the treeline?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For instance, see the image below:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ogsav.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ogsav.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4930" LastEditorUserId="2570" LastEditDate="2016-05-24T23:27:46.707" LastActivityDate="2016-05-27T17:02:19.317" Title="What is the name for the forested areas in mountains below the treeline?" Tags="|mountains|terminology|forest|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7028" PostTypeId="1" CreationDate="2015-12-04T20:06:11.453" Score="4" ViewCount="258" Body="&lt;p&gt;As the polar ice caps disappear, the equatorial regions must take the bulk of extra water due to the earth's spin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is will the tilt of the earth be affected and what would be the consequences? &lt;/p&gt;&#xA;" OwnerUserId="4932" LastEditorUserId="2470" LastEditDate="2015-12-04T22:39:46.873" LastActivityDate="2016-02-03T07:56:36.540" Title="Polar melting and the equator" Tags="|climate-change|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7029" PostTypeId="2" ParentId="7027" CreationDate="2015-12-04T22:55:38.913" Score="1" Body="&lt;p&gt;Between timberline and treeline lies &quot;krumholtz&quot;, a German word meaning broken or bent wood&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Great place to hike.&lt;/p&gt;&#xA;" OwnerUserId="4933" LastActivityDate="2015-12-04T22:55:38.913" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7030" PostTypeId="2" ParentId="7027" CreationDate="2015-12-05T03:32:04.597" Score="5" Body="&lt;p&gt;Forests directly below the &lt;a href=&quot;https://en.wikipedia.org/wiki/Tree_line#Alpine&quot; rel=&quot;nofollow noreferrer&quot;&gt;alpine tree line&lt;/a&gt; are high-elevation or Montane forests.  See more about &lt;a href=&quot;https://en.wikipedia.org/wiki/Montane_ecology&quot; rel=&quot;nofollow noreferrer&quot;&gt;Montane ecology here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9AjVQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9AjVQ.jpg&quot; alt=&quot;treeline image&quot;&gt;&lt;/a&gt;  Image from &lt;a href=&quot;http://www.nature.com/scitable/knowledge/library/global-treeline-position-15897370&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.nature.com/scitable/knowledge/library/global-treeline-position-15897370&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2015-12-13T20:31:07.553" LastActivityDate="2015-12-13T20:31:07.553" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7031" PostTypeId="2" ParentId="7028" CreationDate="2015-12-05T06:22:35.307" Score="3" Body="&lt;p&gt;An interesting question! I suggest you do some 'slightly complex' calculations. Look up the angular momentum of the whole Earth. Then calculate pM.dF where pM is the &lt;em&gt;additional&lt;/em&gt; angular momentum from the melted ice, redistributed as a function of latitudinal angular momentum. dF is &lt;em&gt;differential&lt;/em&gt; redistribution caused by continent-ocean constraints. I'm confident that you will find that the additional differential off-axis angular momentum will be miniscule compared to the total. There will of course be &lt;em&gt;some&lt;/em&gt; effect upon the Earth's spin axis, but this will be just another of the small catalogue of mass distribution effects which contributes to a somewhat chaotic wobble in the Earth's spin axis, which is typically in the order of a meter or two. When global warming gets worse and huge masses of ice /water are redistributed, then I'm guessing that the effect could be orders of magnitude more - tens or hundreds of metres maybe? Also consider that the Earth behaves like a gyroscope, so much of the additional angular momentum will exhibit as rotation around other axes, much as hurricanes rotate in the atmosphere. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-12-05T06:22:35.307" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7032" PostTypeId="2" ParentId="4931" CreationDate="2015-12-05T09:45:03.427" Score="-5" Body="&lt;p&gt;Water is one of the main absorbers of sunlight in the atmosphere. Electromagnetic radiation from the sun is the heat source and water and soil absorb this radiation. Liquid water does not act like a mirror. A mirror will reflect almost all of the sun's light and radiation. Water almost does the opposite. Ice can reflect light and some radiation back. The atmosphere acts like a greenhouse trapping the  the heat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.climatechange.gc.ca/default.asp?lang=en&amp;amp;n=1A0305D5-1&quot; rel=&quot;nofollow&quot;&gt;http://www.climatechange.gc.ca/default.asp?lang=en&amp;amp;n=1A0305D5-1&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www1.lsbu.ac.uk/water/water_vibrational_spectrum.html&quot; rel=&quot;nofollow&quot;&gt;http://www1.lsbu.ac.uk/water/water_vibrational_spectrum.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4617" LastEditorUserId="4487" LastEditDate="2015-12-05T23:43:33.747" LastActivityDate="2015-12-05T23:43:33.747" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7033" PostTypeId="1" CreationDate="2015-12-06T00:03:18.733" Score="8" ViewCount="371" Body="&lt;p&gt;On page 29 of the book &lt;a href=&quot;https://books.google.com/books?id=tRMiJ94mZE0C&amp;amp;printsec=frontcover&amp;amp;source=gbs_ge_summary_r&amp;amp;cad=0#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;noreferrer&quot;&gt;3D Seismic Survey Design by Gijs O. Vermeer&lt;/a&gt;, Vermeer says that the equation for a maximum fold in a 3D survey is the following:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$M = M_i \times M_c$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $M_i$ is the inline fold and $M_c$ is the crossline fold. For a towed streamer, the inline fold is the same as for a 2D geometry which can be expressed as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$M_{i} = \frac{N_{chan}\Delta r}{2\Delta s}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the crossline fold he states that:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;&quot;The midpoint range in the crossline direction of one boat pass equals the number of streamers times the streamer interval divided by two ... normally, the next boat pass is shifted in the crossline direction with this distance, ensuring adjacent midpoint ranges of neighboring boat passes, i.e., no overlap in midpoint coverage between boat passes; hence, crossline fold $M_c = 1$. Therefore, in marine streamer acquisition, usually&lt;/em&gt; $M = M_i$ &quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I feel that I understand why the inline fold is the same for the case of a 2D acquisition geometry, but I am having difficulty understanding the concept of the crossline fold. Specifically from the previous quote, could someone help me to understand what Vermeer means when he says midpoint range and coverage?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any help will be greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="4939" LastEditorUserId="4940" LastEditDate="2015-12-07T01:25:54.320" LastActivityDate="2020-03-10T10:09:21.933" Title="Cross-line fold of a towed-streamer survey" Tags="|geophysics|seismology|seismic|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7034" PostTypeId="1" CreationDate="2015-12-06T04:50:34.733" Score="4" ViewCount="242" Body="&lt;p&gt;In selecting a sample for age-dating of a granite pluton, which site is a better site to collect a sample from, the centre, top or side? Why was this site a better choice? Which dating method would you recommend and why?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that it is better to get a sample from the middle but I'm stuck answering the last two questions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any help would be appreciated!&lt;/p&gt;&#xA;" OwnerUserId="4941" LastEditorUserId="725" LastEditDate="2015-12-06T21:39:51.380" LastActivityDate="2015-12-06T21:39:51.380" Title="Relative dating of granite pluton" Tags="|geochemistry|petrology|geochronology|orogeny|dating|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7036" PostTypeId="1" CreationDate="2015-11-06T14:36:45.513" Score="4" ViewCount="2911" Body="&lt;p&gt;Would earth go the same way as Mars by first losing its magnetic field followed by its atmosphere as its core solidifies and cools down ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At what rate is the earth's core cooling down?. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it slow enough that it would be past time when the sun's temperature rises as it starts its journey into the red giant phase and heat up earth at which point it doesn't matter if earth has its magnetic field or not, or is it fast enough to happen within the next few hundred million years?&lt;/p&gt;&#xA;" OwnerDisplayName="August" LastActivityDate="2016-01-05T07:38:18.160" Title="How long would it take for earth's core to cool down and solidify?" Tags="|mars|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7037" PostTypeId="2" ParentId="7036" CreationDate="2015-11-06T18:06:10.947" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;At what rate is the earth's core cooling down?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The inner core is cooling at the rate of around $55^{\circ} C$ every billion years.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Would earth go the same way as Mars by first losing its magnetic field followed by its atmosphere as its core solidifies and cools down ?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Given enough time, yes; But earth is constantly producing heat though multiple processes, the most important being the decay of radioactive elements with long half lives (for e.g., U-238 has a half life of around 4.5 billion years). As the present temperature of the inner core is estimated to be around  $5000^{\circ} C$, this is going to take tens of billions of years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The magnetic fields are generated by eddy currents in the outer core, which is a liquid layer about 2,300 km thickness. The inner core is growing at the rate of about 1 mm per year, so it is going to 'freeze over' (i.e. solidify) in about 2.3 billion years. Without its liquid outer core, the Earth's magnetic field shuts down, and charged particles emanating from the Sun gradually deplete the atmosphere, like Mars.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is it slow enough?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Well, it is not slow enough for the sun to become a red giant and fry earth, which will happen in 4 billion years or so. But is certainly doesn't matter as we won't be around to witness it. &lt;/p&gt;&#xA;" OwnerDisplayName="aeroalias" LastActivityDate="2015-11-06T18:06:10.947" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7038" PostTypeId="2" ParentId="7036" CreationDate="2015-11-07T22:40:20.740" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Would earth go the same way as Mars by first losing its magnetic field&#xA;  followed by its atmosphere as its core solidifies and cools down ?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;We don't know. The current popular belief is the Sun will engulf it long before that. It is merely a hypothesis, not a theory.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;At what rate is the earth's core cooling down?.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;According to today's set of popular superstitions, it all depends on how quickly the fuel inside the nuclear reactor that is the Earth's core (according to some people) depletes. Estimates vary. There are way too many unknowns, and way too many variables to come up with a concrete number (degrees or terawatts). 50 terawatts is a number that surfaces periodically in various publications, but there's just not enough empirical evidence for the hypothesis to become a theory. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is it slow enough that it would be past time when the sun's&#xA;  temperature rises as it starts its journey into the red giant phase&#xA;  and heat up earth at which point it doesn't matter if earth has its&#xA;  magnetic field or not, or is it fast enough to happen within the next&#xA;  few hundred million years?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Again, according to what we seem to believe today, the Sun will get to us long before that. Which, by the way, is also a hypothesis rather than a theory. No matter how impressive the number of sources, it does not constitute proof. Not in science, anyway.&lt;/p&gt;&#xA;" OwnerUserId="4963" OwnerDisplayName="Ricky" LastActivityDate="2015-11-07T22:40:20.740" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7040" PostTypeId="2" ParentId="7034" CreationDate="2015-12-06T10:44:52.983" Score="2" Body="&lt;p&gt;What exactly are you trying to measure? some of the great North American and Andean batholiths have cooling histories of at least 20 million years, and maybe more than 50 million years. It is perhaps inappropriate to think of the crystallization process as having a single date. Phenocrysts near the top of the pluton are cooler, but may sink to deeper levels where they are partially resorbed or mantled in multiple cycles, giving rise to zoned phenocrysts. It can be a very long process. Generally, late stage pegmatites, which have been enriched in volatiles that depress the melting temperature, will indicate the youngest age of crystallization. Deeper levels of the magma chamber will be older, but really one needs to study the specific field relations, including extent of metamorphic aureole to decide upon the most appropriate younger or older samples. The middle will most probably give a reasonable average date. Remember, what you are measuring is the time of that the mineral cools through its 'closure temperature', which will be slightly to significantly younger than its time of crystallization.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to the method of isotopic dating, K-Ar is generally OK but the relative error bounds get worryingly large for dates &amp;lt; a million years. Ar-Ar is more precise but more expensive. It's also an excellent method, as is Rb-Sr, especially for really old precambrian plutons - provided the sample is fresh. Any weathering or diagenesis messes up the method. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-12-06T10:44:52.983" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7041" PostTypeId="1" CreationDate="2015-12-06T13:29:10.987" Score="1" ViewCount="75" Body="&lt;p&gt;I am reading a paper* about the application of the maximum entropy production (MEP) in Earth science (I'm new to MEP btw). The authors start with the system of gas molecules first. When the system is isolated, it has the maximum entropy and the molecules are distributed randomly. When it get contacted with the hot reservoir, nearby molecules will have higher energy, therefore moving faster and will tend to move to the other side, while colder molecules are not really active, so they will stay in their positions. As a consequence. the molecules will shift to the cold side.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Z6lyJ.png&quot; alt=&quot;image description&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When we replace the hot reservoir with the equator, and the cold reservoir with the pole, we will have the model of planetary system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/evYAy.png&quot; alt=&quot;image description&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, doesn't that mean that more matter will locate in the pole(s) than the equator? In Earth, this would mean that there will be more structured or ordered matters, including organisms in the poles than the equator. This doesn't look right to what we know.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can this be explained?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&lt;sub&gt;*&lt;a href=&quot;http://eprints.soton.ac.uk/272878/1/dyke_2010a.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Maximum Entropy Production Principle: Its Theoretical&#xA;Foundations and Applications to the Earth System&lt;/a&gt;&lt;/sub&gt; &lt;/p&gt;&#xA;" OwnerUserId="4945" LastEditorUserId="4945" LastEditDate="2015-12-07T10:25:28.193" LastActivityDate="2015-12-07T10:25:28.193" Title="Why more matters appear in hot equator, when they should flow to the cold poles?" Tags="|geothermal-heat|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7042" PostTypeId="2" ParentId="7041" CreationDate="2015-12-06T13:50:00.110" Score="2" Body="&lt;p&gt;This is very simple to explain when we consider that the 'model' you have been presented with is a gross oversimplification - a one dimensional mechanism. But the Earth is a multi-phase (air water ice), three dimensional system in which convective currents circulate. Hence there is a counterflow of both air and ocean currents in addition to the basic entropy model. The entire thermal circulation is also massively influenced by considerations of conservation of mass, conservation of energy, and conservation of angular momentum. Its a pretty complex system, as climate modellers are only too aware, and cannot be reduced to any simple model. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-12-06T13:50:00.110" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7043" PostTypeId="2" ParentId="7034" CreationDate="2015-12-06T21:38:42.520" Score="1" Body="&lt;p&gt;The better site for sample collection would be the accessible site where it's possible to pick up a sample. Unless you have a drill rig or an excavator, you are limited to what's exposed. If you still have access to several zones of the pluton, take all of them. The more samples you have, the better it is. By choosing not to sample a certain zone you might be missing out on information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The dating method should be zircon U-Pb dating, unless you have a very good reason why not to. Zircons are stable and robust, and with modern analytical methods it may be possible to resolve more than one age in a single zircon, representing for instance recycled detrital zircons.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-12-06T21:38:42.520" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7044" PostTypeId="2" ParentId="7025" CreationDate="2015-12-06T22:27:20.793" Score="5" Body="&lt;p&gt;&lt;em&gt;This answer was initially wrong. Thank you to mkennedy for pointing this out. I have now corrected it.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Casey's answer is a good one with respect to interpreting a wind direction in general. However, you specifically asked about doing so on a UTM projected map, which implies that you're aware that in some projections, the direction of North on the page varies from point to point. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is indeed true for UTM. UTM is a &lt;a href=&quot;https://en.wikipedia.org/wiki/Transverse_Mercator_projection&quot; rel=&quot;nofollow&quot;&gt;transverse Mercator&lt;/a&gt; projection, which means that most lines of longitude follow curved paths on the projected map.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, UTM is used in narrow zones, as shown in the image in the question. The central meridian of each zone (the line running from north to south in its centre, which has an easting of 500,000m) aligns with a line of longitude, so &quot;up&quot; on the grid corresponds to north. Either side of this the angle of north will diverge, but so long as you are using the correct UTM zone, this divergence should be small (a maximum of about 3 degrees at high latitude at the edge of a zone, less otherwise). Therefore, for many purposes it is still useful to consider a wind direction as an angle on a UTM map. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If greater precision is needed, then some calculation will be necessary - searching for &quot;UTM grid declination&quot; provides a few explanations of how to do this, although I think many are simplified. (I'm not qualified to go into detail on the maths)&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2015-12-08T00:29:40.747" LastActivityDate="2015-12-08T00:29:40.747" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7045" PostTypeId="1" CreationDate="2015-12-06T22:32:03.810" Score="10" ViewCount="307" Body="&lt;p&gt;The &lt;a href=&quot;https://a.atmos.washington.edu/wrfrt/&quot; rel=&quot;nofollow noreferrer&quot;&gt;University of Washington&lt;/a&gt; runs the Advanced Research &lt;a href=&quot;http://www.wrf-model.org/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weather Research &amp;amp; Forecasting (WRF)&lt;/a&gt; model in predictive mode, and then tests the skill of the model anywhere from 12 - 84 hours out from the initialization time.  The accuracy of the wind and the temperature profile are considered to be the most important indicators of the model's skill.  The &lt;a href=&quot;https://www.cmascenter.org/cmaq/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CMAQ&lt;/a&gt; Eulerian grid model is then be used to represent air pollutant dispersion, using the WRF data and grids.&lt;/p&gt;&#xA;&lt;p&gt;I've been told that the models don't do well with grid-spacings any finer than 1/3 km. In fact, some people have said that the 4/3 km spacing can perform just as well, and that we've reached a point where Eulerian grid models don't gain much more by going to finer grids.&lt;/p&gt;&#xA;&lt;p&gt;I know that for modeling pollutant dispersion at fine horizontal scales, &lt;a href=&quot;https://en.wikipedia.org/wiki/Lagrangian_and_Eulerian_specification_of_the_flow_field&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lagrangian methods have historically been used instead of Eulerian grid-cell&lt;/a&gt; methodology. However, with recent developments in computing, gridded modeling domains have been able to use much finer grid-spacings.  What is the finest grid spacing that Eulerian dispersion grid-cell models should realistically use? Why?&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2021-05-28T23:43:01.563" LastActivityDate="2022-12-27T21:07:44.040" Title="What is the smallest grid spacing that Eulerian air quality models should use?" Tags="|meteorology|atmosphere|models|air-quality|grid-spacing|" AnswerCount="0" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="7046" PostTypeId="2" ParentId="6798" CreationDate="2015-12-07T23:06:34.010" Score="5" Body="&lt;p&gt;The ERA archive description document, Berrisford et al (2011) &quot;&lt;a href=&quot;http://www.ecmwf.int/en/elibrary/8174-era-interim-archive-version-20&quot; rel=&quot;nofollow noreferrer&quot;&gt;The ERA-Interim archive Version 2.0&lt;/a&gt;&quot;, provides additional information about what is available.  It's less explicit on the why, but we can read between the lines a bit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The archive consists of re-analyses of the system state at 00, 06, 12, and 18 UTC and re-forecasts out to 10 days initialised from those 00 and 12 UTC states.  Table 9 of that document lists the variables (including the ones that you're interested in) that are stored as accumulations since the start of the re-forecast.  They are stored every 3 hours for the first day of the forecast (steps 3, 6, 9, 12, 15, 18, 21, 24) less frequently thereafter (every 6 or 12 hours).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The variables are not stored for step 0 because their accumulations would be exactly zero&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding using ERA Interim for model forcing, you might consider what &lt;a href=&quot;http://dx.doi.org/10.5194/hess-19-389-2015&quot; rel=&quot;nofollow noreferrer&quot;&gt;Balsamo et al (2015)&lt;/a&gt; do for ERA Land forcing.  They use state variables from steps 3, 6, 9 and 12 and accumulations from steps 12, 15, 18 and 21 (see Fig 1 of that paper).  This inconsistency is because the fluxes (accumulations) are particularly prone to spin-up artefacts in the first few hours of the forecast.  The trade-off is that the states and the fluxes used in the forcing come from slightly different forecasts.&lt;/p&gt;&#xA;" OwnerUserId="106" LastEditorUserId="106" LastEditDate="2017-03-23T14:41:26.153" LastActivityDate="2017-03-23T14:41:26.153" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7048" PostTypeId="1" CreationDate="2015-12-08T22:18:57.307" Score="4" ViewCount="193" Body="&lt;p&gt;I am currently studying the deposition process in coastal environments and I came across a point which I do not understand concerning grading of grain size.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &quot;Petroleum Geology by North F.K.&quot; &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;If deposition exceeds subsidence, high-energy deposits prograde over lower-energy deposits;hence grain size coarsens upwards.&lt;/li&gt;&#xA;&lt;li&gt;If deposition and subsidence are in general equilibrium, stacked or multistorey sand bodies result.&lt;/li&gt;&#xA;&lt;li&gt;If subsidence exceeds deposition, a series of isolated narrow, linear bars of sand become separated by wide strips having less sand. The sand bodies may still coarsen in grain upwards.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I actually don't understand why this happens, I tried to Google it but still no clue.&lt;/p&gt;&#xA;" OwnerUserId="4957" LastEditorUserId="140" LastEditDate="2015-12-10T20:46:15.593" LastActivityDate="2015-12-10T20:49:01.167" Title="Why pro-gradation occurs along coastal environments?" Tags="|geology|rocks|sedimentology|stratigraphy|coastal|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7049" PostTypeId="2" ParentId="694" CreationDate="2015-12-09T02:01:58.177" Score="3" Body="&lt;p&gt;One thing that already exists is the &lt;code&gt;ph5&lt;/code&gt; format from the PASSCAL group: &lt;a href=&quot;https://www.passcal.nmt.edu/content/ph5-what-it&quot; rel=&quot;nofollow&quot;&gt;https://www.passcal.nmt.edu/content/ph5-what-it&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is essentially a port of the SEG Y format that removes some restrictions and adds a bunch of new meta information. It is based on HDF5 and is currently mainly intended as an archival format although I don't see why it could not also be used as a processing format.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Disclaimer for the following paragraphs: I am one of the guys behind it. We have recently been developing a new data format including data provenance for seismology also based on HDF5. Currently it is mainly suitable for passive source data, e.g. earthquakes and stations recording the ambient wavefield - our community has very extensive and well established standards for the meta information which we just incorporate. It would be some work but the concept of seismic sources and receivers translates to the active source case so that might be a valuable direction to investigate. More information: &lt;a href=&quot;http://seismic-data.org&quot; rel=&quot;nofollow&quot;&gt;http://seismic-data.org&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4959" LastActivityDate="2015-12-09T02:01:58.177" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7050" PostTypeId="1" AcceptedAnswerId="7051" CreationDate="2015-12-09T13:14:48.383" Score="2" ViewCount="566" Body="&lt;p&gt;I understand the phenomenon I want to explain is something known as Earth Shine. What is Earthshine and what causes Earthshine? Is it really normal? What exactly is the less illuminated part in the diagram?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WmFr6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WmFr6.jpg&quot; alt=&quot;Earthshine&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4892" LastActivityDate="2015-12-10T14:16:56.867" Title="Old moon in the new moon's arm" Tags="|moon|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7051" PostTypeId="2" ParentId="7050" CreationDate="2015-12-09T14:32:58.760" Score="4" Body="&lt;p&gt;Yes, earthshine is completely normal. It is simply illumination of that part of the moon that is facing away from the sun. This illumination is sunlight that is reflected towards the moon by the Earth. Strictly speaking, it is that reflected light from the Earth that is itself reflected back to Earth so that we can see it. The intensity of Earthshine is highly variable. If the moon was almost in line between Earth and sun then an observer on the dark side of the moon would see the the whole of Earth's disk brighly illuminated by the sun, and hence the earthshine would be about at its maximum. Conversely, when the Earth is nearly between Moon and Sun, an observer on the moon would only see a crescent Earth (apart from man-made city lights), so the Earthshine would be at a minimum. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-12-09T14:32:58.760" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7052" PostTypeId="1" AcceptedAnswerId="7141" CreationDate="2015-12-09T17:39:30.860" Score="4" ViewCount="100" Body="&lt;p&gt;This is my first time using this dataset, so I have probably made an elementary mistake. I am having trouble understanding a file from the NCDC's climate normal dataset:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www1.ncdc.noaa.gov/pub/data/normals/1981-2010/products/precipitation/ann-snwd-avgnds-ge010wi.txt&quot; rel=&quot;nofollow&quot;&gt;http://www1.ncdc.noaa.gov/pub/data/normals/1981-2010/products/precipitation/ann-snwd-avgnds-ge010wi.txt&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a sample of a few rows from the above file:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;USC00064767         105P&lt;/p&gt;&#xA;&#xA;&lt;p&gt;USC00065077          31P&lt;/p&gt;&#xA;&#xA;&lt;p&gt;USC00065445         370S&lt;/p&gt;&#xA;&#xA;&lt;p&gt;USC00069388          66S&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the &lt;a href=&quot;http://www1.ncdc.noaa.gov/pub/data/normals/1981-2010/documentation/precipitation-filenames.txt&quot; rel=&quot;nofollow&quot; title=&quot;documentation&quot;&gt;documentation&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;ann-snwd-avgnds-ge010wi.txt Long-term averages of number of days during the year&#xA;                             with snow depth &gt;= 10 inches&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the readme and the above, I am assuming that the numerical portions of the entries in the second column in the above sample should all be numbers of days per year, so at most 367. &lt;strong&gt;However, some of the values listed above are greater than 367.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any ideas for me, or other places to look? Did I miss any threads on this forum that discuss how idiots can understand NCDC data?&lt;/p&gt;&#xA;" OwnerUserId="4961" LastEditorUserId="4961" LastEditDate="2015-12-28T16:29:00.827" LastActivityDate="2015-12-28T18:45:39.530" Title="NCDC Snowfall Data - Interpretation?" Tags="|meteorology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7053" PostTypeId="2" ParentId="7050" CreationDate="2015-12-09T23:20:15.727" Score="3" Body="&lt;p&gt;You can think of it as the &quot;reverse&quot; of moonshine. When you walk outside at night and there's a full moon, you can actually see quite a lot around you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Same thing - this happens on the moon when there's a &quot;full earth&quot; that lights up everything around. And since you're on earth, you see this from the outside, on the moon.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2015-12-10T14:16:56.867" LastActivityDate="2015-12-10T14:16:56.867" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7054" PostTypeId="1" CreationDate="2015-12-10T05:10:48.973" Score="6" ViewCount="7468" Body="&lt;p&gt;I must admit this is very confusing: one gets different types of information from different sources that often contradict one another.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is said that the main event occurred due to some misguided farming practices; that those practices allowed strong winds to pick up all the topsoil in the area, carry it east, and deposit it into the Atlantic, more or less in toto. This may not be altogether accurate, but that's the impression one gets from reading essays, articles, and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Dust_Bowl&quot;&gt;Wikipedia entry pertaining to the Dust Bowl&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, various sources maintain that it takes 500 years or more to form 1 inch of topsoil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Others suggest coyly that the process can be expedited artificially by burying lots of organic garbage and introducing earthworms to it: a few years of this, and voila - we've got topsoil! (Few of them say how many years, exactly, and where's one supposed to get all those earthworms?)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Still other sources say that because of soil erosion and other intriguing factors we may be running out of arable land. And not just in Kansas either, but all over the globe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With all of the above in mind, my question is: have the areas affected by the Dust Bowl recovered partially, completely, or not at all? How much of that land can be classified as arable once again?&lt;/p&gt;&#xA;" OwnerUserId="4963" LastEditorUserId="543" LastEditDate="2015-12-10T05:34:47.370" LastActivityDate="2020-10-10T18:26:39.310" Title="The Dust Bowl: how's the recovery of all that topsoil going?" Tags="|agriculture|erosion|dust-bowl|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7055" PostTypeId="1" AcceptedAnswerId="7058" CreationDate="2015-12-10T11:22:00.190" Score="3" ViewCount="4007" Body="&lt;p&gt;I am trying to compute accumulated annual precipitation for year 2000-2001 based on the ERA Interim, but I am stuck with some unresolved questions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I download the synoptic monthly means of &quot;total precipitation&quot; from ECMWF for year 2000-2001 with &quot;Select time&quot; set to &quot;00:00:00&quot; and &quot;12:00:00&quot; respectively, and chose &quot;Select step&quot; as &quot;3&quot;, I get a *.nc -file with 48 time steps. The file also contains a &quot;scale_factor&quot; and &quot;add_offset&quot;. I assume that I must use those values in (add_offset + (downloaded data * scale_factor)) to get actual precipitation in meters? And I assume that if I sum the 48 time steps of data (corrected with add_offset and scale_factor) and divide by 2 (2 years of data) then I get the average accumulated precipitation per year. Is this correct?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What then puzzles me is that the &quot;scale_factor&quot; is very low (3.9E-8), meaning that the values I get will be almost equal to the &quot;add_offset&quot; which is 0.0013. Are there any obvious mistakes I make? Or do any of you know of a guide that is more elaborate than the documentation found at ECMWF? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks a lot in advance for any ideas.&lt;/p&gt;&#xA;" OwnerUserId="4964" LastActivityDate="2015-12-10T22:56:00.920" Title="ERA Interim, how to handle total precipitation" Tags="|precipitation|reanalysis|scaling|era|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7056" PostTypeId="1" AcceptedAnswerId="7062" CreationDate="2015-12-10T17:20:35.937" Score="22" ViewCount="6993" Body="&lt;p&gt;A relative of mine has recently introduced me to the modern flat earth theory, which she believes in. Setting aside for the moment that it is ridiculous, and that sending up some balloons with cameras on would provide evidence to the contrary, how could one evidence that it is in fact spherical from ground based observation? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I immediately thought about citing the observations of Aristotle and measurements of Eratosthenes, something that one can do themselves, but of course they have an answer for that regarding curving light to explain variation of the sun's elevation with latitude. Also refraction backed up by observations of ships on the horizon appearing to be above the horizon (due to refraction) and so light-based observations of a curved body of water are out. To make it even harder, the belief has been adjusted to allow for a flat earth that curves slightly but is not spherical, so objects gradually disappearing over the horizon aren't proof and neither is observing the curvature from a plane! For every argument there is a counter argument, and I, as a layman, don't know how to prove e.g. that the light isn't curving as described.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Without getting into countering non-scientific flaws such as the massive amount of government-level collusion that would be needed to maintain this conspiracy, how might one go about demonstrating it or designing a practical experiment for which the conclusion cannot be refuted. Is this even possible when someone can claim e.g. light curving through the atmosphere in a particular way, without having to back it up? I'm not familiar enough with scientific theory to know how one establishes certainty, or if it is based on a balance of probability (i.e. more proof of one theory than of the contrary).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: This is a thought exercise only, I do not expect to actually convince my relative while she is going through a personal crisis for which this is one of many symptoms, that is a separate issue. She holds a degree in aeronautical engineering so it isn't caused by a lack of intelligence. &lt;/p&gt;&#xA;" OwnerUserId="4967" LastActivityDate="2023-08-13T08:07:27.043" Title="How to quickly or easily prove the world is spherical?" Tags="|geophysics|geography|earth-observation|" AnswerCount="12" CommentCount="20" ContentLicense="CC BY-SA 3.0" />
  <row Id="7057" PostTypeId="2" ParentId="7048" CreationDate="2015-12-10T20:43:16.483" Score="1" Body="&lt;p&gt;If deposition exceeds subsidence, then the water column shallows, the environment becomes more high energy, and so instead of muds and silt, the sediment would be coarser sand and gravel, so coarsening up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If deposition and subsidence are equal, then the energy of the environment does not change, so similar grain sizes will be found throughout.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If subsidence exceeds deposition, then I'd expect the grain size to ultimately become smaller as the environment becomes more low-energy as the water column deepens. But what you wrote could refer to coarse material being less frequently reworked in such an environment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Progradation merely refers here to the progression seen, as over time in the sediment size as a basin generally fills with sediments reflecting shallower environments, I think it's typically taught by the progression of sediments seen as a delta progrades into a basin. First with deep water muds, which coarsen upwards as the delta moves into the basin depositing sediment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what remains in the layered sediments we see, has a complex relation to the time of deposition, which might be more info than you require.(here's a link to a good diagram, which may help. &lt;a href=&quot;https://books.google.co.uk/books?id=mDs5wOdVYTUC&amp;amp;pg=PA18&amp;amp;lpg=PA18&amp;amp;dq=geology%20define%20progradation%20time&amp;amp;source=bl&amp;amp;ots=3N5tmJOXgy&amp;amp;sig=8jSrfAl6md-mxCxYqsdUjY4apo4&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwifp_HrktLJAhUDdXIKHcJ8B-wQ6AEIOzAF#v=onepage&amp;amp;q=geology%20define%20progradation%20time&amp;amp;f=false&quot; rel=&quot;nofollow&quot;&gt;LInk&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="140" LastEditorUserId="140" LastEditDate="2015-12-10T20:49:01.167" LastActivityDate="2015-12-10T20:49:01.167" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7058" PostTypeId="2" ParentId="7055" CreationDate="2015-12-10T22:56:00.920" Score="6" Body="&lt;p&gt;First of all, these netCDF files follow the CF Metadata Conventions, which describe the use of &lt;code&gt;scale_factor&lt;/code&gt; and &lt;code&gt;add_offset&lt;/code&gt; in &lt;a href=&quot;http://cfconventions.org/Data/cf-conventions/cf-conventions-1.6/build/cf-conventions.html#packed-data&quot; rel=&quot;noreferrer&quot;&gt;section 8.1 Packed data&lt;/a&gt; of the conventions description.  In short, you're applying them correctly:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If both attributes are present, the data are scaled before the offset is added.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, I think that you've selected the wrong fields for your purpose.  The total precipitation variable is an accumulation since the start of the re-forecast, and you've selected a monthly mean of accumulations over the first 3 hours of the 00Z re-forecasts and the same thing from the 12Z re-forecasts.  This means that you're missing the accumulated precipitation from hours 3 to 12 of the re-forecasts, so your annual mean estimates might only be 1/4 of any ballpark values you're expecting.  I suspect that you need to choose &lt;code&gt;step=12&lt;/code&gt; rather than &lt;code&gt;step=3&lt;/code&gt;, as &lt;a href=&quot;http://www.ecmwf.int/en/how-can-i-get-monthly-means-daily-forecast-accumulations-eg-precipitation-era-interim-data-server&quot; rel=&quot;noreferrer&quot;&gt;described in the ERA FAQ&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also note, I think the comment in that FAQ about the monthly mean from daily mean data availability being &quot;planned&quot; but &quot;not yet implemented&quot; is out of date and that may be the better route to calculate the annual means (see also section 3 of &lt;a href=&quot;http://www.ecmwf.int/en/elibrary/miscellaneous/8174-era-interim-archive-version-20&quot; rel=&quot;noreferrer&quot;&gt;Berrisford et al, 2011&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2015-12-10T22:56:00.920" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7059" PostTypeId="2" ParentId="694" CreationDate="2015-12-11T06:26:21.560" Score="2" Body="&lt;p&gt;The SEG has a sitting committee for SEG-Y revision 2, which has debated the need to adopt changes to SEG-Y since the last revision that are needed (such as removing trace length limits for continuous data, formats for passive data, etc.). If you want to do something about what SEG-Y for the future should look like, You should join the SEG and volunteer for the committee. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;People need to remember that SEG-Y is an interchange/exchange format, not a processing format. Acquisition formats (like SEG-D) are good for field acquisition. SEG-Y is for data exchange. In fact, is was a replacement for the older SEG Exchange format (SEG-X, get it?). No one will wade into the argument about a standard for a processing format because it has even more issues of compatibility and legacy than SEG-Y. &lt;/p&gt;&#xA;" OwnerUserId="2557" LastActivityDate="2015-12-11T06:26:21.560" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7060" PostTypeId="2" ParentId="7056" CreationDate="2015-12-11T07:06:51.023" Score="6" Body="&lt;p&gt;The simplest method I can think of is to observe a hand-held global positioning system ('GPS'), which shows the position of visible satellites, directly overhead, and at various angles from the vertical. Once satellites disappear over the horizon, they reappear again exactly in accordance with an orbital trajectory around a sphere.&#xA;Secondly, go to Google Earth - a composite of satellite photographs - and take a spin around the world. At all points the Earth appears as a globe. How is this possible if the Earth is flat?&#xA;Thirdly, there are more than 100,000 commercial flights per day, which can be tracked on sites such as &lt;a href=&quot;https://flightaware.com/live/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Flight Aware&lt;/a&gt;. Not one of these flights has ever seen an edge to the Earth. How come, if the Earth is flat?&#xA;Fourthly, the sun and all the planets and dwarf planets have all been examined by probes and found to be spherical (more or less). On what basis should one expect the Earth to be any different?&#xA;Fifthly, apart from minor purturbances caused by local geology, the Earth's gravity is pretty much uniform everywhere. How can this be possible in a flat Earth where the mass distribution would be very heterogeneous?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are many more possible tests, but as you say, one can't change the minds of such people. 'Flat Earthers', like creationists and climate change deniers, have already made up their mind, and don't want to be confused by the facts.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="6093" LastEditDate="2017-06-05T12:46:39.197" LastActivityDate="2017-06-05T12:46:39.197" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7061" PostTypeId="2" ParentId="7054" CreationDate="2015-12-11T07:44:04.257" Score="5" Body="&lt;p&gt;Soil is not a single uniform material. When wind erosion takes hold, as in the infamous 'dust bowl' of the 1930s, it is the uppermost A horizon, and to a lesser extent the B horizon that is mainly lost. The lost soil takes with it most of the organic carbon, and it is this component that is most difficult to replace. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rates of soil loss are primarily factors of the underlying geology and climate. A wetter and warm climate will regenerate soil very much faster than a cold dry climate. Basalt and shale will break down into soil much faster than, for example, quartzite or granite. The rate of rock weathering is not quite the same as the rate of soil formation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a first approximation, rate of weathering = rate of soil formation + rate of mass loss by various processes.&lt;br /&gt;&#xA;Wakatsuki and Rasyudin (1992) &lt;em&gt;Rates of Weathering and Soil Formation&lt;/em&gt;, Geoderma, V52, 3-4, gives a good assessment of such rates.&lt;br /&gt;&#xA;Their best estimate is that soil formation occurs at 370–1290 (mean = 700) kg ha−1 yr−1. Or roughly 0.3 mm per decade, excluding the lost organic carbon. This is equivalent to about 3 mm of new soil generation since the great dust bowl. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, no, the lost soil is nowhere near replenished yet. Moreover, the impact of climate change does not bode well for the future of soil regeneration.  &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="595" LastEditDate="2015-12-11T10:33:03.390" LastActivityDate="2015-12-11T10:33:03.390" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7062" PostTypeId="2" ParentId="7056" CreationDate="2015-12-11T09:40:11.917" Score="21" Body="&lt;p&gt;To answer my own question based on the useful comments here, my favorite methods were:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The earth's shadow cast on the moon during an eclipse. It is easy to observe and the flat earth counter argument is so insane that if it is offered you should just walk away.&lt;/li&gt;&#xA;&lt;li&gt;Shadows differ from place to place. The same experiment as Eratosthenes but you can carry this out locally with a piece of large card, 2 obelisks and a light source casting a shadow. Now bend the card and observe the change in shadows. The same effect could then be observed on the earth's surface. The counter argument of curved rays of light is weakened by the fact you can reproduce it locally.&lt;/li&gt;&#xA;&lt;li&gt;triple-right triangle:&#xA;You move in a straight line for a long enough distance Turn right&#xA;90° degrees, walk in that same direction for the same distance Turn&#xA;again to the right 90° degrees and walk again the same distance&#xA;After this you'll end up at the starting point. This is not possible&#xA;on a flat surface since you'd just be &quot;drawing&quot; a half-finished&#xA;square. Not sure how practical this is as you'd have to walk a long way!&lt;/li&gt;&#xA;&lt;li&gt;Although not technically about the earth being flat, in a flat earth theory the sun orbits, or at least moves over the earth. A simple way to discount this is observing parallax with surrounding stars.&lt;/li&gt;&#xA;&lt;li&gt;It is not too difficult to prove the earth curves at least, such as by observing more objects over the horizon the further you go up. And even measuring the curvature is not difficult. Thus I believe a person could drive the length of the African continent, observing the curvature and measuring the straight line distance, and modelling that alone would show the earth curves beyond what could be acceptable on a flat earth, without all the water running off the edge!&lt;/li&gt;&#xA;&lt;li&gt;One I haven't seen mentioned yet is showing that the flat earth map cannot work. In a flat earth, apparently, the north pole is at the centre and south pole is a ring around the outside. Pick a land mass close to the south pole, and another on the opposite side of the map. The distance you would need to travel to reach one from the other by e.g. flying east around the map would be enormous and not congruent with the flight times or shipping times in real life.&lt;/li&gt;&#xA;&lt;li&gt;Earth is warmer near the equator, for obvious reasons in a non-flat world but the counter argument would have to be pretty imaginative.&lt;/li&gt;&#xA;&lt;li&gt;Sunrise and sunset do not happen at the same time for everyone on earth. The difference in timezones, which can be observed by taking a trip to different countries, cannot reasonably be explained by a curved but nearly flat earth.&lt;/li&gt;&#xA;&lt;li&gt;Experiments with gravity, but flat-earthers reject the complication of gravity (things drop just because). So I avoided this one, but it would be a compelling way to demonstrate why people on the other side of a spherical earth are not on their heads.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="4967" LastEditorUserId="4967" LastEditDate="2015-12-11T09:58:31.103" LastActivityDate="2015-12-11T09:58:31.103" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="7063" PostTypeId="2" ParentId="2287" CreationDate="2015-12-11T15:45:37.753" Score="1" Body="&lt;p&gt;It seems that the CO2 fertilization has been over-estimated in past studies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2879.html&quot; rel=&quot;nofollow&quot;&gt;Nature Climate Change article,Large divergence of satellite and Earth system model estimates of global terrestrial CO2 fertilization&lt;/a&gt; by W. Kolby Smith,    Sasha C. Reed,  Cory C. Cleveland,  Ashley P. Ballantyne,   William R. L. Anderegg,     William R. Wieder,  Yi Y. Liu   &amp;amp; Steven W. Running    &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Atmospheric mass balance analyses suggest that terrestrial carbon (C) storage is increasing, partially abating the atmospheric [CO2] growth rate, although the continued strength of this important ecosystem service remains uncertain. Some evidence suggests that these increases will persist owing to positive responses of vegetation growth (net primary productivity; NPP) to rising atmospheric [CO2] (that is, ‘CO2 fertilization’). Here, we present a new satellite-derived global terrestrial NPP data set, which shows a significant increase in NPP from 1982 to 2011. However, comparison against Earth system model (ESM) NPP estimates reveals a significant divergence, with satellite-derived increases (2.8 ± 1.50%) less than half of ESM-derived increases (7.6  ±  1.67%) over the 30-year period. By isolating the CO2 fertilization effect in each NPP time series and comparing it against a synthesis of available free-air CO2 enrichment data we provide evidence that much of the discrepancy may be due to an over-sensitivity of ESMs to atmospheric [CO2], potentially reflecting an under-representation of climatic feedbacks and/or a lack of representation of nutrient constraints. Our understanding of CO2 fertilization effects on NPP needs rapid improvement to enable more accurate projections of future C cycle–climate feedbacks; we contend that better integration of modelling, satellite and experimental approaches offers a promising way forward.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastActivityDate="2015-12-11T15:45:37.753" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7064" PostTypeId="1" AcceptedAnswerId="7071" CreationDate="2015-12-11T15:48:47.963" Score="1" ViewCount="87" Body="&lt;p&gt;Most of sand on Earth when inspected at close range reveal tiny shells as in sea shells. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a picture of the Martian sand at a close distance:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gnIzh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gnIzh.jpg&quot; alt=&quot;Martian sand&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can Earth's tiny shells be seen in sand at similar distance?&lt;/p&gt;&#xA;" OwnerUserId="4566" LastEditorUserId="20" LastEditDate="2015-12-14T03:02:41.963" LastActivityDate="2015-12-14T03:02:41.963" Title="Can miniature shells be seen in Earth's sand at this resolution?" Tags="|mars|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7065" PostTypeId="2" ParentId="7064" CreationDate="2015-12-11T20:01:32.123" Score="5" Body="&lt;p&gt;Firstly I would disagree with your premise that 'most of Earth's sand contains tiny shells resembling sea shells'. Such biogenic sand is certainly true of some biologically productive sedimentary environments, but certainly far from all. For example, try finding shells in most of the sand in the Sahara desert, or any other desert for that matter. You will only succeed if the sand is reworked from previous biogenic sandstone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to the resolution of shells at the apparent scale of your photograph, it depends upon the biota involved. The bioclasts vary from several millimetres to true microfossils - far below any visible resolution, and maybe even below resolution of small microscopes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I assume that any close up photo of Mars sand would have been magnified, contrast stretched, and computer image enhanced. Had there been any bioclastic grains, I am sure it would have been front page news around the world.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-12-11T20:01:32.123" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7066" PostTypeId="1" CreationDate="2015-12-11T21:31:06.840" Score="4" ViewCount="1072" Body="&lt;p&gt;When gold, or some other metals, such as copper, are found, they are often found in large nuggets. But, from what I understand, gold is produced in quite stochastic stellar processes. As such, shouldn't the distribution of gold and other elements be rather uniform, or at least conglomerated according to the stellar process by which they were created? Why do we see large gold nuggets? Shouldn't we find gold mixed uniformly with all the other elements created along side it in its stellar process?&lt;/p&gt;&#xA;" OwnerUserId="4973" LastEditorUserId="2470" LastEditDate="2015-12-11T22:26:29.290" LastActivityDate="2019-05-19T04:48:06.710" Title="Why does gold and other metals conglomerate" Tags="|geology|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7067" PostTypeId="2" ParentId="7066" CreationDate="2015-12-11T22:57:11.723" Score="3" Body="&lt;p&gt;Some things to consider. Even if elements are formed randomly in stars that does not necessarily imply that the elements will be distributed evenly and randomly when the star explodes. Following the explosion of a star there will be a gravitational attraction between the elements created within the star which will cause clumping/agglomeration of the elements.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other thing to consider is chemical attraction due to ionic charges and the lack or excess of electrons in the outer shells of atoms which causes atoms to chemically combine with other atoms to form molecules.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many elements and molecules are soluble in water. When conditions change, such as temperature, pressure or chemical attraction, metals can precipitate out of solution and collect en-mass, sometimes forming nuggets.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-12-11T22:57:11.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7068" PostTypeId="2" ParentId="7066" CreationDate="2015-12-12T14:01:43.453" Score="2" Body="&lt;p&gt;In addition to Fred's comments, there is growing evidence that some metallic elements, including gold, are bio-concentrated to billions of times the concentration in ambient solutions. In addition, once a minute 'nugget' or grain is established, it acts as a nucleating agent for further deposition. Another factor is the mico-environment's position on a 'pH-redox fence'. If the right combination of acidity/alkalinity and electrical potential is encountered, than extraordinary precipitation can occur, even where and when one would not normally expect it. This is particularly the case in which buried organic carbon (reducing agent) comes into contact with circulating groundwater. Over time remarkable concentrations, including sizeable gold nuggets, can precipitate from vanishingly small aqueous concentrations. Also recall that in quite mild geothermal - hydrothermal conditions, of 100 to 300 deg C, for example, the rates of chemical precipitation of 'insoluble' elements like gold, can be tens of thousands of times faster than would be seen under normal meteoric temperatures.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-12-12T14:01:43.453" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7069" PostTypeId="2" ParentId="5400" CreationDate="2015-12-12T22:26:13.637" Score="4" Body="&lt;p&gt;There are many types of devices used for measuring lightning. The first natural radio wave receiver was also the first lightning detector invented by Alexander Stepanovich Popov. In 1896 Popov presented a paper on a wireless lightning detector he had built that detected radio noise from lightning strikes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Popov's discovered that lightning produces radio waves. Popov discovery originates from the fact that lightning produces light and sound. If the sound of the thunder is produced by the rippling of air because of the expansion of air produced by the heat of the lightning, then Popov thought that lightning could produce other forms of energy too. This other form of energy turned out to be radio waves.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Popov's designed a very sensitive coherer (a primitive radio signal detector) connecting it to an antenna that received the radio waves from the lightning. The coher was also connected to a circuit with a battery and a relay that rang a bell and sent a pluse to a chart recorder that could mark the occurrence of the lightning.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Popov built a radio receiver that could only receive natural radio waves from lightning (then the only good source of radio waves) leading him after to build an artificial radio transmitter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The radio waves of lightning travel much farther than the light and sound it produces so a lightning detector can measure the distance to the lightning strike. Some of today's lightning detectors use this basic concept. With four of them you can combine the time at which each device measures the radio signal from the lightning and determine the strike location. Meteorologist today call this detector a ground-based lightning sensor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are other devices used to measure lightning using other kinds of antennas and signal processing techniques like radar and temperature data. Lightning detection can also be from advanced devices on artificial satellites. Using direct observations such as with the Geostationary Lightning Mapper a near-infrared optical transient detector can detect changes in an optical scene, indicating the presence of lightning, frequency and location of lightning events.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dbAAe.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dbAAe.jpg&quot; alt=&quot;Alexander Stepanovich Popov radio receiver and lightning detector.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Alexander Stepanovich Popov radio receiver and lightning detector.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;&lt;strong&gt;Further information:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alexander Stepanovich Popov: &lt;a href=&quot;https://en.wikipedia.org/wiki/Alexander_Stepanovich_Popov&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Alexander_Stepanovich_Popov&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Popov Lightning Detector: &lt;a href=&quot;http://weatherbreak2.creighton.edu/?p=1809&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://weatherbreak2.creighton.edu/?p=1809&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A Brief History of Lightning Detection: &lt;a href=&quot;http://scijinks.jpl.nasa.gov/lightning-detection/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://scijinks.jpl.nasa.gov/lightning-detection/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geostationary Lightning Mapper (GLM): &lt;a href=&quot;http://www.goes-r.gov/spacesegment/glm.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.goes-r.gov/spacesegment/glm.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3040" LastEditorUserId="3040" LastEditDate="2016-01-08T04:15:49.167" LastActivityDate="2016-01-08T04:15:49.167" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7070" PostTypeId="2" ParentId="7066" CreationDate="2015-12-13T01:30:17.767" Score="2" Body="&lt;p&gt;There are processes that can move certain elements around (including gold) when you take water, pressurise and heat it up, such as happens in the Earth's crust. These processes will preferentially take one element relative to another. Some will take gold and leave other stuff behind. When this gold-bearing water accumulates in some place, the gold will stay there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an example, let's take a mixture of salt and sand. If you let water flow over it, the sand will stay behind but it will dissolve the salt and redeposit it wherever the water are going to. So in principle it's the same thing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I made a drawing for another answer some time ago:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/2393/725&quot;&gt;Why do gold deposits form only in certain areas of the earth?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;When gold, or some other metals, such as copper, are found, they are often found in large nuggets.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That's not actually correct. They are not &quot;&lt;em&gt;often&lt;/em&gt; found in large nuggets&quot;. Whenever they are found in large nuggets it is indeed spectacular, but this is extremely rare (and becomes rares as more of those are found). Most gold is mined in very low concentrations. A good estimate for how much gold is in the rocks that are mined for is is 1 gram of gold per 1 tonne of rock mined. That's very little.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-12-13T01:30:17.767" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7071" PostTypeId="2" ParentId="7064" CreationDate="2015-12-13T01:41:54.417" Score="3" Body="&lt;p&gt;Quoting from the NASA website:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The image covers an area 1.4 inches by 1.1 inches (3.6 by 2.7 centimeters). It was taken by the Mars Hand Lens Imager (MAHLI) camera on the rover's arm on Dec. 5, 2015, during the 1,184th Martian day, or sol, of Curiosity's work on Mars. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes, it is possible to see shells in that scale. It is also possible that there are shells that are smaller than you would be able to resolve.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An important point here is not only the shape of the sand grains (be it shell fragments, or some other shape) but also their composition. The vast majority of shells and shell fragments on Earth are made of calcite or aragonite (CaCO&lt;sub&gt;3&lt;/sub&gt;). The rest are made of apatite (Ca&lt;sub&gt;5&lt;/sub&gt;(PO&lt;sub&gt;4&lt;/sub&gt;)&lt;sub&gt;3&lt;/sub&gt;(OH)) and silica (SiO&lt;sub&gt;2&lt;/sub&gt;). &lt;a href=&quot;http://mars.jpl.nasa.gov/msl/mission/technology/scienceinstruments/insituinst/&quot; rel=&quot;nofollow&quot;&gt;Curiosity has quite a lot of instruments on board for material analysis&lt;/a&gt;. Getting the composition of the sand, in addition to its shape, is just as important for identifying its source.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-12-13T01:41:54.417" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7073" PostTypeId="1" CreationDate="2015-12-13T21:41:16.137" Score="12" ViewCount="7268" Body="&lt;p&gt;The two major constituents of the Earth's core are iron and nickel.  In documentaries and scientific conversations, iron gets more attention than nickel, probably because it makes up a bigger percentage of the core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But before I consider this scenario—where it was nickel that makes up the bigger percentage instead of iron—I must ask:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why does iron make up the majority of Earth's core as opposed to nickel?  Does either metal have an advantage over the other?  If so, which advantage?  If nickel is the number-one metal of the core instead of iron, how would the magnetic field be affected?&lt;/p&gt;&#xA;" OwnerUserId="4985" OwnerDisplayName="JohnWDailey" LastEditorUserId="725" LastEditDate="2018-02-12T23:23:23.100" LastActivityDate="2018-02-12T23:23:23.100" Title="Why is Earth's Core Iron?" Tags="|earth-history|core|geomagnetism|planetary-formation|iron|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7074" PostTypeId="2" ParentId="7073" CreationDate="2015-12-13T22:27:44.060" Score="20" Body="&lt;p&gt;Simply put, the amount of iron in the solar system/universe is higher than nickel due to a process called nucleosynthesis. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically at it's origin the universe comprised only of hydrogen, through nuclear fusion heavier elements were/are being created. Fundamentally, hydrogen is fused into heavier elements in the star, our sun is currently turning massive amounts of hydrogen into helium through the proton-proton chain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Eventually as a star gets older you start seeing fusion of heavier elements, helium, carbon, nitrogen, etc up until you hit iron at which point you hit what is known as the iron peak  where fusing iron atoms together requires more energy than is release. Heavier elements are all formed during supernovas and thus we see lower level of abundance. That being said the abundance of nickel is still higher than all the other heavier metals.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Stellar_nucleosynthesis&quot;&gt;https://en.wikipedia.org/wiki/Stellar_nucleosynthesis&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://physics.info/nucleosynthesis/&quot;&gt;http://physics.info/nucleosynthesis/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user15999" LastActivityDate="2015-12-13T22:27:44.060" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7076" PostTypeId="2" ParentId="7073" CreationDate="2015-12-14T00:28:10.830" Score="13" Body="&lt;p&gt;I can only answer the question of why is it mostly iron. Not too sure of the magnetic properties of iron versus nickel.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As said in another answer, there is simply much more iron around than nickel. But the earth has also a large amount of other metals: silicon, magnesium, calcium, aluminium. So why is the core made of iron-nickel and not the other stuff? The answer is in the oxygen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you take a metal and oxygen, you form an oxide - usually a solid, brittle, &quot;earthy&quot; material. The best example is metallic iron + oxygen = rust. But not all metals are the same - some metals &quot;like&quot; oxygen more than others. If you have one atom of magnesium and another of iron, and only one atom of oxygen around - it will first bond with magnesium. Considering the entire oxygen budget of the Earth, there was enough oxygen to bond with all of the silicon, magnesium, calcium, aluminium (and just about the rest of the periodic table) to form the solids we usually refer to as rocks. By the time you got to the less oxygen-loving elements, such as nickel and iron, you had very little oxygen left. You had enough to oxidise some of the iron and nickel, but not all of it. That's why there was a lot of iron and nickel that was left as metals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During Earth's formation, the entire thing was molten. Metallic iron and nickel are denser than the oxidised stuff (&quot;rocks&quot;), so it sank to the bottom, forming the metallic core. The oxidised metals ended up forming the mantle on top of it.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2015-12-14T00:28:10.830" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7077" PostTypeId="1" CreationDate="2015-12-14T01:08:21.627" Score="1" ViewCount="1093" Body="&lt;p&gt;Back home, the average depths of the world's oceans--and the Mediterranean Sea--are as follows:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Atlantic--3926 meters&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pacific--4028 meters&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Indian--3963 meters&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Arctic--1205 meters&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Southern--4500 meters&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mediterranean--1500 meters&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this alternate Earth, the average depths are as follows:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Atlantic--4679 meters&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pacific--6896 meters&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Indian--3295 meters&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Arctic--3460 meters&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Southern--2735 meters&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mediterranean--3767 meters&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How would these changes in depth affect the world's climate and ocean currents? &lt;/p&gt;&#xA;" OwnerUserId="4985" LastActivityDate="2015-12-14T09:45:56.223" Title="If the Oceans Were Deeper" Tags="|ocean|climate|oceanography|ocean-currents|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7078" PostTypeId="2" ParentId="7056" CreationDate="2015-12-14T01:46:08.953" Score="9" Body="&lt;p&gt;Just after sunset, call a friend some number of time zones to the west and ask them where the sun is in their sky. Or, just before sunrise, call a friend some number of time zone to the east and ask them where the sun is in the sky. Then, think about why the sun is at different heights for you and for your friend. The more time zones this experiment crosses, the harder it will be to explain this as a feature of a flat earth.&lt;/p&gt;&#xA;" OwnerUserId="534" LastEditorUserId="534" LastEditDate="2019-10-24T00:17:44.673" LastActivityDate="2019-10-24T00:17:44.673" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="7079" PostTypeId="1" CreationDate="2015-12-14T03:04:10.203" Score="12" ViewCount="464" Body="&lt;p&gt;The average proportion of naturally occurring semi-heavy water or &lt;a href=&quot;https://en.wikipedia.org/wiki/Heavy_water&quot;&gt;deuterated water&lt;/a&gt;, $\ce{^2HHO}$ or $\ce{HDO}$, is about 1 molecule in 3200. The proportion comes from the fact that one hydrogen in 6400 is in the form of deuterium. The heavy water, $\ce{D2O}$, proportion is about 1 molecule in 41 million ($\ce{6400^2}$) as part of a dynamic equilibrium between normal water, semi-heavy and heavy water (water containing 50% H and 50% D, is in fact a balance between 25% of $\ce{H2O}$ and $\ce{D2O}$ and the rest is $\ce{HDO}$). &#xA;I understand that the &lt;a href=&quot;https://en.wikipedia.org/wiki/Vienna_Standard_Mean_Ocean_Water&quot;&gt;Vienna Standard Mean Ocean Water (VSMOW)&lt;/a&gt; has a set proportion equal to the average proportion, but heavy water abundance changes slightly from one kind of water to another.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is how much does it change? What oceans have a higher proportion of heavy water? As a hydrogen bond with deuterium is stronger than a normal one, would we expect any biological effects from the different abundances?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2015-12-14T19:43:32.200" LastActivityDate="2015-12-15T13:46:42.343" Title="How different is the proportion of heavy water ($\ce{^2H2O}$) in the different oceans?" Tags="|ocean|water|isotopic|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7080" PostTypeId="1" AcceptedAnswerId="7088" CreationDate="2015-12-14T07:47:03.747" Score="3" ViewCount="119" Body="&lt;p&gt;Cooled lava looks black, but why the whole volcano, even near crater, doesn't always appear black like cooled lava?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="725" LastEditDate="2017-05-02T20:42:24.260" LastActivityDate="2017-05-04T16:36:16.110" Title="Why doesn't the whole volcanic cone appear black?" Tags="|volcanology|geomorphology|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7081" PostTypeId="2" ParentId="7077" CreationDate="2015-12-14T09:45:56.223" Score="2" Body="&lt;p&gt;Might not be the answer you're looking for but the most obvious effect would be a sinking of land and a spreading out of the oceans.   Granite, basalt, glaciers and oceans are in a sense, balanced like weights on a scale by their enormous mass and the gravity of Earth.   By replacing a mile or so of basalt rock with water at the bottom of the oceans the weight would be unbalanced and the continents would sink, similar to how some land is currently &lt;a href=&quot;https://en.wikipedia.org/wiki/Post-glacial_rebound&quot; rel=&quot;nofollow noreferrer&quot;&gt;rebounding&lt;/a&gt; from the last ice age.  The net effect over time would be a few hundred meters of sea level rise if the oceans were to become that much deeper. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I suspect that's not what you were looking for in your question.   You probably wanted to know about weather or oceanic temperature effects.   That's a little harder.   I can give a sort of answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Larger oceans would mean more dissolved atmospheric gas.  I had no luck finding good estimates as to how much atmosphere is dissolved in the deep oceans overall, I was able to do a very crude calculation using this &lt;a href=&quot;http://www.waterencyclopedia.com/Re-St/Sea-Water-Gases-in.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;website&lt;/a&gt; and estimates that there's about 50 times as much CO2 in the Oceans as there is in the atmosphere.   Now, my estimate is hugely crude, but there may be an entire Earth's atmosphere, both Oxygen and Nitrogen trapped in the oceans.   The deep oceans hold a fair bit of Oxygen and Nitrogen so by making the oceans bigger, the effect might be a thinner atmosphere.   10% thinner?   20%?   5%  I couldn't guess the amount, but something somewhere in that range seems probable. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding deep ocean currents, it's difficult (perhaps impossible) to say how currents might change.  In general, ocean currents, while not simple, seem to follow fairly simple patterns.   My guess is that the amount of depth you've added isn't enough to change that, though if you were to make oceans significantly deeper, you might get a few layers of circulation, not the three, sometimes four layers we currently have.  (see pictures).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/w3UKm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/w3UKm.jpg&quot; alt=&quot;http://oceanography.earthednet.org/Mini_Studies/Deep_Ocean_Circulation/Deep_Ocean_Circulation_files/image009.jpg&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3xVAa.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3xVAa.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://oceanography.earthednet.org/Mini_Studies/Deep_Ocean_Circulation/Deep_Ocean_Circulation.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source of pictures&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Larger, deeper oceans would also provide a greater heat sink that would take longer to warm up or cool down with the rise and fall of glacial periods.   It's possible that there would be no glacial periods with these changes, but predictions get kind of speculative there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's all I can think of.  I invite corrections and additions.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2015-12-14T09:45:56.223" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7083" PostTypeId="1" CreationDate="2015-12-14T12:27:52.730" Score="1" ViewCount="100" Body="&lt;p&gt;I am carrying out an exercise on digital mapping of soil properties. I have tried several high resolution DEMs like 90 m and 30 m but their resolution is not good enough. Kindly assist.&lt;/p&gt;&#xA;" OwnerUserId="4997" LastEditorUserId="2536" LastEditDate="2017-01-20T08:43:49.290" LastActivityDate="2018-01-11T17:46:35.390" Title="High resolution DEM for digital soil mapping and modelling" Tags="|remote-sensing|soil|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7085" PostTypeId="1" CreationDate="2015-12-14T16:22:33.173" Score="2" ViewCount="374" Body="&lt;p&gt;Related to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7077/if-the-oceans-were-deeper&quot;&gt;If the Oceans Were Deeper&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Appalachian Range, at first glance, doesn’t seem so different—low-lying hills covered in forest dominating the eastern landscape. However, they are taller—7,244 feet above sea level at the highest, compared to Mount Mitchell back home, which is over 6500 feet above sea level. An even more radical difference is its history.  Back home, the Appalachians first appeared 480 million years ago as the result of a collision between North America and Africa.  On Great Lakes Earth, the Appalachians are no older than two and a half billion years, the result of several volcanic uplifts.  Indeed, the Appalachians on Great Lakes Earth are a labyrinth of solid gneiss and granite, a macrocosm of the Black Hills, which we have but Great Lakes Earth doesn’t.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mountains of the American West have some major differences.  For starters, only the Rockies stand firm—no Coast Range and most certainly no Sierra Nevada.  Like the Appalachians, the Rockies on Great Lakes Earth have a different road from ours.  If we connect the following dots from our North America, we might have an idea as to how the Rockies in Great Lakes Earth might be arranged:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;•   Kugluktuk, Nunavut, Canada&lt;/p&gt;&#xA;&#xA;&lt;p&gt;•   Yellowknife, Northwest Territories, Canada&lt;/p&gt;&#xA;&#xA;&lt;p&gt;•   Calgary, Alberta, Canada&lt;/p&gt;&#xA;&#xA;&lt;p&gt;•   Williston, North Dakota, United States&lt;/p&gt;&#xA;&#xA;&lt;p&gt;•   Rapid City, South Dakota, United States&lt;/p&gt;&#xA;&#xA;&lt;p&gt;•   Lamar, Colorado, United States&lt;/p&gt;&#xA;&#xA;&lt;p&gt;•   Clovis, New Mexico, United States&lt;/p&gt;&#xA;&#xA;&lt;p&gt;•   Ciudad Juarez, Mexico&lt;/p&gt;&#xA;&#xA;&lt;p&gt;•   San Luis Potosi, Mexico&lt;/p&gt;&#xA;&#xA;&lt;p&gt;•   Tampico, Mexico&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While our Rockies vary in width from 70 to 300 miles, their Rockies vary between 75 and 200 miles.  While our Rockies stand no taller than 14,440 feet above sea level, the tallest peak in a Great Lakes Rockies is measured to be 14,505 feet.  Not only that, they aged differently as well.  Back home, our Rockies formed between 80 and 55 million years ago through the Laramide Orogeny, the subduction of the North American and Pacific Plates at a shallow angle.  Their Rockies first formed 120 million years ago as the result of a collision between the the St. Lawrence Limestone and the continental Laramia.  They stopped becoming active shortly before the dinosaur extinction.  Even so, the rate of decay in Great Lakes Earth is significantly smaller than back home, for the main rocks are schist, granite and gneiss, tough rocks with small vulnerabilities.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;True to the planet’s name, North America is full of large lakes.  The largest of which is Agassiz.  To have an idea on the shape, size and scope of Agassiz, we must look at the familiar faces of the Great Lakes—Superior, Michigan, Huron, Erie and Ontario—and then flood off the entire basin.  That is Lake Agassiz, 95,000 square miles and 257 meters deep on average.  Agassiz started out as a few tectonic depressions that expired some 20 million years ago.  They wouldn’t become one lake until the ice bulldozed the depressions during the Pleistocene glaciations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are great lakes west of the Rockies as well.  What we’d recognize as western Utah is for them Lake Bonneville, 25,000 square miles and a thousand feet deep.  Lake Bidahochi in northeastern Arizona is over 30,000 square miles in area and is the source of the Colorado River.  Unlike Agassiz, the tectonic depressions in Bonneville and Bidahochi are still volcanically active.  Only six times in Great Lakes Earth’s recent geologic history did ice carve these lakes into the distinctive shapes that we can see today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Comparing Great Lakes Earth to ours, we’d find that all land below sea level has become water, and Death Valley, the continent’s lowest and hottest point, is no exception.  In its place is Lake Manly, a long but narrow strip of water fed by rivers flowing from Bidahochi.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It’s interesting that if we see the West Coast of Great Lakes North America, we’d see a real different shape.  While the Atlantic coastline is similar to ours, the Pacific coastline looks as though 75 meters of sea level have risen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is up north, from British Columbia to Alaska, that the iconic peaks of the Cascades stand firm.  What we’d recognize as the Alaska Range in southern Alaska is an extension of the Cascades, turning the over 20,000-foot Denali into America’s largest volcano.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Yellowstone mantle plume is still present.  Except that instead of Wyoming’s northwestern corner, it can be found in northeastern California.  The latest eruption was in circa 250 AD and it wouldn’t awaken again for another 800,000 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the place of the original Cascades is the Sea of Missoula.  Using the flood basalts of the Columbia River as a reference, we’d get a good idea on the shape, area size and location of the Sea of Missoula.  It helps with the Great Lakes of the West to make western North America a plentiful place to be.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Comparing their South America to ours, there’s not much to find.  The Andes themselves, though equal in length and width to our own, are taller and more active—the highest currently stands 30,111½ feet above sea level (not 22,841, as was the case back home) and the annual average of volcanic eruptions measures in at 50.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How would all these differences affect the New World's climate, weather and landscape?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2015-12-17T21:18:42.933" Title="Great Lakes Earth: The Americas" Tags="|meteorology|geology|climate|geography|hypothetical|" AnswerCount="0" CommentCount="16" ClosedDate="2015-12-16T23:12:25.660" ContentLicense="CC BY-SA 3.0" />
  <row Id="7086" PostTypeId="1" CreationDate="2015-12-14T16:45:14.450" Score="12" ViewCount="2309" Body="&lt;p&gt;I viewed sunset times in some major Eastern U.S. cities including Boston, New York, Philadelphia, Boston / D.C. and Miami. It seems that the earliest sunset time starts around the first week of December, stays the same for the next week, and starts to get later again by December 18.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The winter solstice is around Dec. 22, which is considered the shortest day (i.e. length of sunlight) of the year. So, it seems that the earliest sunset time is a few weeks ahead of the shortest day. Why is that?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Chicago sunset/sunrise from &lt;a href=&quot;http://www.sciquill.com/analemma/&quot; rel=&quot;noreferrer&quot;&gt;http://www.sciquill.com/analemma/&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/gp6EQ.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gp6EQ.gif&quot; alt=&quot;http://www.sciquill.com/analemma/&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5003" OwnerDisplayName="DanF" LastEditorUserId="111" LastEditDate="2015-12-15T01:52:29.807" LastActivityDate="2021-12-08T16:44:31.967" Title="Why does the earliest sunset time not coincide with the shortest day of the year?" Tags="|diurnal-cycle|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7087" PostTypeId="2" ParentId="7086" CreationDate="2015-12-14T17:27:48.323" Score="5" Body="&lt;p&gt;If you follow the sunset timing for the equator you will notice that although the day remains pretty much the same all year round, the sunset moves up and down twice a year. The biggest difference is about a half hour.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is due to the changing speed of the orbit of Earth. Earth's orbits is slightly oblong. Therefore on the longer parts the planet picks up speed. Which means that although Earth made a full rotation, since it is further in its orbit it is still seeing the sun. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This happens twice, on both longer stretches of the orbit. However the effect on one is more pronounced than the other. This is because in one leg Earth is speeding away from the sun, which slows it a bit, and in the other it is coming toward the sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The longest and shortest days are on both points of the oblong circle but the later sunset is before that point. &lt;/p&gt;&#xA;" OwnerUserId="5002" LastActivityDate="2015-12-14T17:27:48.323" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7088" PostTypeId="2" ParentId="7080" CreationDate="2015-12-14T17:40:29.747" Score="4" Body="&lt;p&gt;The cooled lava might be covered by ashes. So depending of the amount of ashes and the wind you might have a black volcano or a gray volcano. Many volcanoes are formed by layers of lava and ash.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Volcano#/media/File:Volcano_scheme.svg&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Volcano#/media/File:Volcano_scheme.svg&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5004" LastActivityDate="2015-12-14T17:40:29.747" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7089" PostTypeId="2" ParentId="4778" CreationDate="2015-12-14T17:58:20.377" Score="2" Body="&lt;p&gt;You will only have aftershocks, which are always smaller than the original earthquake. Aftershocks are the accomodation of the surface to its new position after the big movement of the original earthquake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But you might have another big earthquake near the original one, because since big earthaquakes means than a whole line of earth moves (not a single point, but a line where plates touch), you might have another masive earthquake next to the original.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That happened on 1960 on Chile. On May 21 an earthquake 7.4 Ms hit a zone north to the city of Concepción, and the next day another earthquake, this time 9.5 Ms hit the zone next to the first one.&#xA;Actually the first earthquake was the sum of three earthquakes, and the second was the sum of 37 earthquakes distributed on 1000km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/1960_Concepci%C3%B3n_earthquakes&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/1960_Concepci%C3%B3n_earthquakes&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5004" LastEditorUserId="5004" LastEditDate="2016-09-12T12:31:50.007" LastActivityDate="2016-09-12T12:31:50.007" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7091" PostTypeId="1" CreationDate="2015-12-14T18:35:34.823" Score="6" ViewCount="77" Body="&lt;p&gt;It used to be thought that the unusual amount of water on our planet was the result of a giant collision between proto-Earth and a dwarf planet or planetoid called Theia. I recently heard of some oxygen isotope research which indicates that the giant impact hypothesis wasn't necessary to explain the oceans. So is the giant impact hypothesis still alive, modified or dead?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="111" LastEditDate="2015-12-14T18:52:17.987" LastActivityDate="2015-12-15T13:37:37.787" Title="Is the giant impact hypothesis still alive?" Tags="|water|planetary-formation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7092" PostTypeId="2" ParentId="7086" CreationDate="2015-12-14T20:26:22.417" Score="2" Body="&lt;p&gt;The length of the day is the distance between sunrise and sunset. Sunrise and sunset around the longest and shortest day of the year do not go in the same &quot;direction&quot; as the earth makes the &quot;turn&quot; around the closest and farthest points of the oval orbit. That is, the sunrise and sunset times are a function of both the rotation of the earth as well as the movement of the Earth in its orbit around the sun (and the angle of the axis to the plane of the orbit).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, there are times when sunset starts getting later (which would make the day longer) but sunrise is still getting later. For example, in Baltimore Maryland sunrise/sunset on December 5 was 7:11/4:43, December 12 was 7:17/4:44, December 19 is 7:22/4:46, and December 26 will be 7:25/4:49&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The earliest sunset in Baltimore was at 4:43 from December 4 through December 12, while sunrise while sunrise continues getting later until January 10 (7:27 A.M.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This means that the length of the day continues getting shorter until sunrise gets later less than sunset is getting later and then (sunrise) starts getting earlier.&lt;/p&gt;&#xA;" OwnerUserId="5008" LastEditorUserId="5008" LastEditDate="2015-12-20T21:13:03.170" LastActivityDate="2015-12-20T21:13:03.170" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7093" PostTypeId="2" ParentId="7080" CreationDate="2015-12-15T12:24:27.733" Score="2" Body="&lt;p&gt;An active volcanic crater is generally a highly toxic environment full of highly-acidic, sulphur, chloride and fluoride-rich gasses emanating from, and reacting with hot rock. Weave into the mix sudden exposure to oxygen and meteoric water (which may become reactive steam) within the rock, and you have a cocktail of extreme weathering, geochemical reaction and rock corrosion. So the original black rock doesn't stay black for long. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One bizarre and very rare exception is carbonatite volcanoes, such as occur in remote parts of the East African Rift Valley. These 'lavas' start off as white magma, and almost immediately turn black upon exposure to air.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-12-15T12:24:27.733" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7094" PostTypeId="2" ParentId="7091" CreationDate="2015-12-15T13:37:37.787" Score="4" Body="&lt;p&gt;The giant impact hypothesis was not formulated to address the issue of how the Earth acquired its waters. At the time the giant impact hypothesis was formulated, the dominant theory for how the Earth acquired its waters was impacts by comets and wet asteroids during the late heavy bombardment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The giant impact hypothesis was instead formulated to address the issue of how the Earth acquired its very large moon.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-12-15T13:37:37.787" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7095" PostTypeId="2" ParentId="7079" CreationDate="2015-12-15T13:46:42.343" Score="4" Body="&lt;p&gt;For detailed information, see &lt;a href=&quot;https://books.google.de/books?hl=de&amp;amp;id=Ez26jkzTauoC&amp;amp;dq=Ferronsky%20polyakov&amp;amp;q=dueterium#v=onepage&amp;amp;q=ocean&amp;amp;f=false&quot; rel=&quot;nofollow&quot;&gt;Isotopes of the Earth's Hydrosphere&lt;/a&gt;, especially chapter 3 which is &quot;Isotopic Composition of Ocean Water&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the surface, deuterium fraction is maximized in regions of high evaporation, and minimized in areas with ice.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the deep ocean, there is about 2% above average deuterium in arctic, and 2% below average near Antarctica.  There is a general increasing trend from south to north.  &lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2015-12-15T13:46:42.343" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7096" PostTypeId="2" ParentId="7086" CreationDate="2015-12-15T15:37:46.380" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;So, it seems that the earliest sunset time is a few weeks ahead of the shortest day. Why is that?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It's because we measure time by a clock rather than by a sundial. That the latest sunrise and earliest sunset don't occur on the winter solstice pretty much (but not completely) vanishes when one looks at time as measured by a sundial.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From early December to mid January, a solar day (the time from one local noon to the next) is 24 or more seconds longer than is a day as measured by a clock, with the discrepancy peaking at about 30 seconds on December 25 or so. While the timing of sunrise and sunset is more or less symmetrical about local solar noon, this discrepancy between the length of a day as measured by a sundial versus the 24 hour day as measured a clock means that in the northern hemisphere, the earliest sunset (as measured by a clock) occurs sometime before the winter solstice and that the latest sunrise occurs sometime after the winter solstice. (How much depends on latitude.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This discrepancy between solar time and clock time is a consequence of the Earth's axial tilt and the eccentricity of the Earth's orbit. How these two two effects combine is called &lt;a href=&quot;http://aa.usno.navy.mil/faq/docs/eqtime.php&quot; rel=&quot;noreferrer&quot;&gt;the equation of time&lt;/a&gt;. The axial tilt results in a sine wave with a period of six months and zero crossings at the solstices and equinoxes. The eccentricity results in a sine wave with a period of a year (plus a tiny bit) with zero crossings at perihelion (when the Earth is closest to the Sun) and aphelion (furthest from the Sun).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Right now, perihelion occurs a couple of weeks after the northern hemisphere winter solstice. (This is just coincidental. In 5000 years or so, perihelion will occur around the time of the spring equinox, and in 10000 years, around the time of the summer solstice.) The difference between length of day as measured by a sundial vs a clock currently reaches its peak in late December because of that coincidence.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-12-15T15:37:46.380" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7097" PostTypeId="1" CreationDate="2015-12-15T16:49:19.233" Score="11" ViewCount="3098" Body="&lt;p&gt;During the recent (2015) Paris climate negotiations there was a lot of talk in the media about &amp;quot;limiting the global temperature increase to 2 degrees Celsius&amp;quot;.&#xA;I keep wondering about what this value of 2 degrees really means, and what can we read from this value.  It is said to refer to some sort of global average temperature. How is this average calculated, how meaningful can it be?&lt;/p&gt;&#xA;&lt;p&gt;Temperature is what physicists call an intensive quantity, as opposed to extensive quantities which are additive.  Thus there is no physically natural way to define an &lt;em&gt;&amp;quot;average temperature&amp;quot;&lt;/em&gt;.  Any averaging process will necessarily be arbitrary and ad hoc.  It can be done through space and through time, with various sampling frequencies in both, and with various averaging methods (arithmetic, geometric, various weighted versions, etc.).  It is indeed possible to construct pathological functions &lt;span class=&quot;math-container&quot;&gt;$f(x)$&lt;/span&gt; the estimated average of which will be wildly different based on the averaging method, or even based on something as innocent looking as the sampling frequency.&lt;/p&gt;&#xA;&lt;p&gt;Of course these difficulties don't mean that any average of an intensive quantity is meaningless.  It is completely reasonable to try to mathematically formalize the intuitive concept of warming.  But they do mean that it has to be done carefully.  It is also quite striking for those of us who are not climate scientist that the amount of warming we are talking about is on a scale (0-2 &lt;span class=&quot;math-container&quot;&gt;$^\circ$&lt;/span&gt;C) that is much smaller than the temperature variation we might experience during a time scale as short as a day or distance scales as short as a few hundred of kilometers.&lt;/p&gt;&#xA;&lt;p&gt;So, to finally come to concrete questions:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;How is this average calculated exactly?  Why is the specific method used considered to be reasonable?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="5011" LastEditorUserId="2470" LastEditDate="2021-02-24T22:43:05.177" LastActivityDate="2021-02-26T02:56:40.153" Title="How exactly is the &quot;global average temperature&quot; calculated and how reasonable is this method?" Tags="|climate-change|temperature|" AnswerCount="3" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="7098" PostTypeId="1" CreationDate="2015-12-15T18:18:30.353" Score="1" ViewCount="109" Body="&lt;p&gt;As I understand it, the Pleistocene ice ages were dictated by three major factors suggested by the Serbian geophysicist Milutin Milankovitch--eccentricity (orbital shape), obliquity (axial tilt) and precession (direction of rotation in relation to fixed stars).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The one identical factor between our Earth and this alternate Earth is the eccentricity--no lower than 0.000055 and no higher than 0.0679 over a period of 100,000 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Back home, Earth's axial tilt varies between 22.1 and 24.5 degrees in a period of 41,000 years. In this alternate Earth, the tilt varies between 20 and 25 degrees in a period of 61,500 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Back home, Polaris will be the North Star for a total length of roughly 26,000 years. In this alternate Earth, Alioth in the Big Dipper will be the North Star for a total length of 46,800 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With these changes, how would Earth's climate been different? How would these changes affect the extents of the ice ages?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastEditorUserId="543" LastEditDate="2015-12-16T00:09:32.340" LastActivityDate="2015-12-16T00:09:32.340" Title="Altering the Milankovitch Cycles" Tags="|climate|ice-age|earth-rotation|milankovitch-cycles|world-building|" AnswerCount="0" CommentCount="6" ClosedDate="2015-12-17T21:45:50.727" ContentLicense="CC BY-SA 3.0" />
  <row Id="7099" PostTypeId="2" ParentId="7073" CreationDate="2015-12-15T21:22:27.313" Score="7" Body="&lt;p&gt;The main reason that there is more iron than nickel in the Earth's core, and in the universe generally, is that Nickel-56 beta-decays to Iron-56 (via cobalt-56).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Much nickel-56 forms in &lt;a href=&quot;https://en.wikipedia.org/wiki/Asymptotic_giant_branch&quot; rel=&quot;noreferrer&quot;&gt;Asymptotic Giant Branch stars&lt;/a&gt; and supernovae.  However, nickel-56 decays with a half-life of 6 days.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In nuclear fusion in stars, He-4 nuclei (&lt;a href=&quot;https://en.wikipedia.org/wiki/Alpha_particle&quot; rel=&quot;noreferrer&quot;&gt;alpha particles&lt;/a&gt;) form from hydrogen. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In large stars, fusion does not stop when helium is formed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Instead, carbon-12 is formed &lt;a href=&quot;https://en.wikipedia.org/wiki/Triple-alpha_process&quot; rel=&quot;noreferrer&quot;&gt;from three alpha particles&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon-burning_process&quot; rel=&quot;noreferrer&quot;&gt;Carbon-12 nuclei fuse&lt;/a&gt; to yield oxygen-16, neon-20 and magnesium-24.  All these nuclei have equal number of protons and neutrons.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Silicon-burning_process&quot; rel=&quot;noreferrer&quot;&gt;series continues, by fusing one after another alpha particle&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Iron-52 fuses to Nickel-56.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it is not energetically favorable to add another alpha particle to go from nickel-56 to zinc-60.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nickel-56 decays to Iron-56.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in summary, it is the combination of the fact that Nickel-56 is at the end of a series of favorable alpha particle fusions, and the fact that Nickel-56 decays to Iron-56, that makes iron particularly abundant.&lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2015-12-15T21:22:27.313" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7100" PostTypeId="1" AcceptedAnswerId="7101" CreationDate="2015-12-16T02:57:57.813" Score="3" ViewCount="168" Body="&lt;p&gt;I was under the impression GWP (global-warming potential) is the measure of a gas' impact on global warming, in comparison with CO2. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;E.g. methane has a GWP of 86 over 20 years - &lt;a href=&quot;https://en.wikipedia.org/wiki/Global-warming_potential&quot; rel=&quot;nofollow&quot;&gt;Wikipedia&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Comparing paper and ceramic cups for GWP, &lt;a href=&quot;https://www.tcd.ie/GreenPages/documents/refiller_cup_comparison.pdf&quot; rel=&quot;nofollow&quot;&gt;this article&lt;/a&gt; (page 24) shows GWP in kilograms. Does this make sense to show GWP in kg? Can anyone explain why?&lt;/p&gt;&#xA;" OwnerUserId="5014" LastActivityDate="2015-12-16T17:19:24.073" Title="What is meant by Global-warming Potential (GWP)?" Tags="|climate|climate-change|co2|gas|methane|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7101" PostTypeId="2" ParentId="7100" CreationDate="2015-12-16T03:28:08.917" Score="5" Body="&lt;p&gt;Rather than using the GWP as a ratio, they are expressing the GWP as compared to a release of &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_dioxide_equivalent&quot; rel=&quot;nofollow&quot;&gt;$\ce{CO2}$ with equivalent radiative effects&lt;/a&gt;.  To use their numbers use the mass they give you and a GWP ratio of 1 for that mass (as if it were carbon dioxide).  From what I've seen for chemical industry sales and marketing literature it is fairly common that they express GWP this way in units of &quot;$\ce{CO2}$ equivalent&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, they are saying whatever their product is made of and its production methods have the same radiative forcing as $x$ kg of $\ce{CO2}$.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="64" LastEditDate="2015-12-16T17:19:24.073" LastActivityDate="2015-12-16T17:19:24.073" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7103" PostTypeId="1" AcceptedAnswerId="7209" CreationDate="2015-12-16T14:30:38.050" Score="6" ViewCount="1491" Body="&lt;p&gt;I'm trying to understand what causes the sea-surface temperature (in the open ocean and coastal areas) and the air temperature immediately above it to be different. I know very little about the subject, as I have not taken a class on boundary layers. I would think that in the winter, air is colder than the ocean (and vice-versa in the summer) because the ocean has a higher heat capacity than air. Am I right? What other factors contribute to the differences between SST and local air temperature, and are there notable exceptions to what I say above? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If there are relevant papers or texts on this topic, please let me know...&lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorUserId="543" LastEditDate="2015-12-17T01:11:58.410" LastActivityDate="2016-01-09T08:58:56.583" Title="SST and air temperature differences" Tags="|ocean|temperature|planetary-boundary-layer|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7104" PostTypeId="1" AcceptedAnswerId="7108" CreationDate="2015-12-16T15:35:49.223" Score="6" ViewCount="371" Body="&lt;p&gt;Here's a graph from &lt;a href=&quot;http://www.johnstonsarchive.net/other/quake1.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;johnstonsarchive.net&lt;/a&gt; showing energy released by earthquakes and, however reliable this graph is, it shows huge differences in earthquake activity. About how big percent is the energy of quakes caused by humans?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/NAlZY.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NAlZY.gif&quot; alt=&quot;rate of natural catastrophes&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5016" LastEditorUserId="2958" LastEditDate="2018-12-29T22:21:08.837" LastActivityDate="2018-12-29T22:21:08.837" Title="How significant is human influence on seismic activity?" Tags="|climate-change|earthquakes|glaciology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="7105" PostTypeId="1" CreationDate="2015-12-16T19:15:30.060" Score="5" ViewCount="69" Body="&lt;p&gt;Double-barreled question which may not precisely belong here!  Input nonetheless greatly appreciated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question:  &lt;strong&gt;To what extent would a nuclear reactor breach in the Mediterranean sea affect the sustenance of the ecosystem?  Would its bounty be rendered inedible to humans?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Additionally, could Europe adapt without starvation?  Any general thoughts on long-term implications and extenuating factors?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT::: An example cause might be the catastrophic failure or aggressive destruction in the sea of a typical naval Pressurized Water Reactor used in nuclear marine propulsion.&lt;/p&gt;&#xA;" OwnerUserId="2764" LastEditorUserId="2764" LastEditDate="2015-12-17T16:36:17.540" LastActivityDate="2015-12-17T16:36:17.540" Title="Possible Effects of a Nuclear Reactor Breach in the Mediterranean" Tags="|radioactivity|mediterranean|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7106" PostTypeId="1" AcceptedAnswerId="7107" CreationDate="2015-12-16T20:14:58.133" Score="6" ViewCount="2494" Body="&lt;p&gt;The thing I find most interesting about Pangaea is that, if all the landmasses were connected, it leaves a massive amount of uninterrupted ocean everywhere else. It seems to suggest that there is a significant difference between the two areas of Earth; one area being where Pangaea was located, and the other area being the rest of Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why would only that portion of the Earth be above water? Is there something significant about where Pangaea was located which made it different from the rest of the Earth?&lt;/p&gt;&#xA;" OwnerUserId="4494" LastEditorUserId="111" LastEditDate="2015-12-18T19:04:57.703" LastActivityDate="2018-08-14T02:34:16.397" Title="Pangaea - Why did all the land mass form in one area?" Tags="|plate-tectonics|earth-history|planetary-formation|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7107" PostTypeId="2" ParentId="7106" CreationDate="2015-12-16T20:30:10.767" Score="12" Body="&lt;p&gt;The formation and break up of supercontinents have happened throughout Earth's history in almost a cyclical manner. There may have been many others supercontinents before Pangaea and the total number of such is uncertain. The 4 last supercontinents are: &lt;a href=&quot;https://en.wikipedia.org/wiki/Columbia_%28supercontinent%29&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nuna&lt;/a&gt; (some other people call it Columbia) that was present in the period 2.0–1.8 Ga (billion years ago or 1000 million years ago, if you use the long notation); &lt;a href=&quot;https://en.wikipedia.org/wiki/Rodinia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rodinia&lt;/a&gt; that formed around 1.1 Ga and lasted until about 750 Ma; &lt;a href=&quot;https://en.wikipedia.org/wiki/Pannotia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pannotia&lt;/a&gt; that lasted 650-560 Ma; and finally, Pangaea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The location of the supercontinents seems to have varied throughout Earth's history and it doesn't seem likely that there was something special about the location of Pangaea, except the underlying forces of plate tectonics. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=ovT90wYrVk4&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; is good animation of the evolution in time of the different supercontinents.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2018-08-14T02:34:16.397" LastActivityDate="2018-08-14T02:34:16.397" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="7108" PostTypeId="2" ParentId="7104" CreationDate="2015-12-17T01:23:02.440" Score="4" Body="&lt;p&gt;You have an interesting graph there. In response to your question, I would say that if we actually use the Mw (moment magnitude) measure of seismic activity (which is related to energy release via slip on a fault), we would see that most of the Earthquakes 'caused' by humans (and note that there are still only a few examples of this, (such as the 5.7 Prague, Oklahoma Earthquake), are limited to intraplate earthquakes which only exceed 4 in rare instances such as the above. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The exact 'percent' of energy release due to induced (human-caused) seismicity would probably not even approach single digits, but possibly reside in values approaching zero, when you consider that the vast majority of earthquakes take place at plate boundaries and outnumber induced earthquakes by a large amount. &lt;/p&gt;&#xA;" OwnerUserId="4810" LastActivityDate="2015-12-17T01:23:02.440" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7110" PostTypeId="1" AcceptedAnswerId="7112" CreationDate="2015-12-17T16:37:40.907" Score="4" ViewCount="214" Body="&lt;p&gt;I was just pondering this question; do meteorites containing significant magnetic metal elements displace paleomagnetism the same way that magnetic striping on the ocean floor occurs? When the meteorites pass through the atmosphere do they actually get hot enough to go beyond the curie point of any metal-bearing minerals that are within and then subsequently align with the magnetic field as they cool back down? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If so; I assume that would that be indicative of the Earth having an inner liquid core producing a magnetic field or could something else be the contributing factor to the alignment?&lt;/p&gt;&#xA;" OwnerUserId="5020" LastActivityDate="2015-12-17T20:05:43.633" Title="Are the magnetic elements of meteorites that have struck Earth aligned with the magnetic field?" Tags="|meteorite|geomagnetism|earth-observation|paleomagnetism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7111" PostTypeId="1" CreationDate="2015-12-17T19:29:40.297" Score="2" ViewCount="190" Body="&lt;p&gt;Today, through plate tectonics, the islands of Indonesia and the Philippines stand as barriers between the Indian and Pacific oceans. In fact, there once was a warm ocean current flowing from the Pacific to the Indian before the volcanic upbringings of the islands detoured the current to the North Pacific.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But if the plate tectonics are rearranged to the extent that neither Indonesia nor the Philippines exist, how would the difference in current circulation affect the climates of Asia and Australia?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastEditorUserId="4985" LastEditDate="2015-12-21T14:32:04.927" LastActivityDate="2015-12-21T14:32:04.927" Title="A Wide-Open Passage Between the Indian and the Pacific" Tags="|climate|oceanography|ocean-currents|hypothetical|world-building|" AnswerCount="0" CommentCount="4" ClosedDate="2016-05-15T13:44:51.800" ContentLicense="CC BY-SA 3.0" />
  <row Id="7112" PostTypeId="2" ParentId="7110" CreationDate="2015-12-17T20:05:43.633" Score="4" Body="&lt;p&gt;The surface of 'iron' meteorites certainly gets hot enough to exceed the curie temperature, hence the characteristic ablation texture that you see on meteorites in museums. However, that's a surface feature, and wouldn't affect the interior of all but the smallest of meteorites. The tumbling passage through the atmosphere for just a few seconds, coupled with the shock of impact when it landed is such that there wouldn't be any clear magnetic signature of anything within the outer skin of the meteorite. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In large meteorites, consisting of solid Ni-Fe, the residual magnetism seems to reflect the magnetic field of that part of the solar system from whence they came. Other meteorites contain fragmentary components of varying magnetic orientation, also, (presumably) related to magnetic fields within the early history of the solar system. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-12-17T20:05:43.633" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7113" PostTypeId="1" CreationDate="2015-12-18T02:17:52.343" Score="3" ViewCount="540" Body="&lt;p&gt;What makes pollen varieties useful index fossils? Should pollen not be a poor index fossil?&lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="140" LastEditDate="2015-12-19T18:12:21.620" LastActivityDate="2016-03-19T09:28:01.357" Title="What makes pollen varieties useful index fossils?" Tags="|paleontology|stratigraphy|geobiology|archaeology|paleobotany|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7114" PostTypeId="1" CreationDate="2015-12-18T04:23:07.173" Score="5" ViewCount="120" Body="&lt;p&gt;I am not an earth scientist but for many years I have wondered about the following. I am curious if this has already been explored by scientists? If so, what is the theory formally called? and what is the consensus of the scientific community about such a theory?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;CONCEPT:&lt;/strong&gt; When you have new tires put on your car the mechanic will put the tire on a machine to &lt;a href=&quot;https://en.wikipedia.org/wiki/Tire_balance&quot; rel=&quot;noreferrer&quot;&gt;check the balance&lt;/a&gt; and then add small lead or zinc weights on the rim to correct any wobble. Even though the weights are tiny by comparison they play a critical role in effective lifespan of the tires. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the past couple hundred years humans have been moving &quot;tiny&quot; amounts of weight around the surface of the earth. We add weights when we build &lt;a href=&quot;http://www.newgeography.com/content/002808-world-urban-areas-population-and-density-a-2012-update&quot; rel=&quot;noreferrer&quot;&gt;large cities&lt;/a&gt;, or &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_largest_dams_in_the_world&quot; rel=&quot;noreferrer&quot;&gt;dam rivers&lt;/a&gt;. We take away weights when we &lt;a href=&quot;http://webecoist.momtastic.com/2009/09/10/massive-man-made-and-natural-holes/&quot; rel=&quot;noreferrer&quot;&gt;excavate&lt;/a&gt; and &lt;a href=&quot;http://geochange.er.usgs.gov/sw/changes/anthropogenic/subside/&quot; rel=&quot;noreferrer&quot;&gt;overdrafting&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There also of course are &lt;strong&gt;natural events&lt;/strong&gt; that move &quot;tiny&quot; surface weights around, such as &lt;a href=&quot;https://nsidc.org/cryosphere/glaciers/quickfacts.html&quot; rel=&quot;noreferrer&quot;&gt;glacier movement&lt;/a&gt;, &lt;a href=&quot;http://www.bbc.com/news/world-asia-31848255&quot; rel=&quot;noreferrer&quot;&gt;island formation&lt;/a&gt;, &lt;a href=&quot;http://geology.about.com/library/bl/blbigcalderas.htm&quot; rel=&quot;noreferrer&quot;&gt;caldera eruptions&lt;/a&gt;, and &lt;a href=&quot;http://www.telegraph.co.uk/news/worldnews/australiaandthepacific/australia/11489673/Largest-ever-meteorite-crater-found-in-Australian-outback.html&quot; rel=&quot;noreferrer&quot;&gt;meteor strikes&lt;/a&gt;. This last of course also imparts a vector of kinetic energy change due to impact force.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;THEORY:&lt;/strong&gt; I call this personal idea the &quot;Wobbly Tire Theory&quot; on the presumption that Earth has for millennia been dealing with &lt;a href=&quot;https://en.wikipedia.org/wiki/Chandler_wobble&quot; rel=&quot;noreferrer&quot;&gt;axis wobble&lt;/a&gt; but has usually had time to adjust/stabilize between significant changes. However, in the past 200 years or so we have been making a lot of man-made changes in these weights in a timespan that is a geologic blink-of-an-eye. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I speculate that these rapid changes may be affecting the earths rotation in subtle ways. For example, I wonder could such changes affect the core's rotation vector in any way?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;So back to my original Question&lt;/strong&gt;: Does this theory (including &lt;strong&gt;OR&lt;/strong&gt; excluding the last about man-made effects) already exist among geophysicists and others? What name(s) does it go by? And what details, if any, are there on the scientific consensus of this concept?&lt;/p&gt;&#xA;" OwnerUserId="3267" LastActivityDate="2015-12-18T13:55:11.303" Title="Wobbly Tire Theory -- Is there an existing theory that fits the following description?" Tags="|geophysics|earth-rotation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7115" PostTypeId="2" ParentId="7114" CreationDate="2015-12-18T13:55:11.303" Score="3" Body="&lt;p&gt;I don't know if this theory has any formal name, but of course you are correct in assuming that any mass redistribution on or in the planet will affect it's axis of rotation, causing a wobble. Small re-distributions are happening all the time with growing and melting ice, ocean currents sloshing water from one side of an ocean to another (as in the El Nino). Theoretically, a whale swimming across an ocean will create an axial wobble, albeit far too small to measure. Earth and sea tides, climate change, plate tectonics etc... The list goes on and on, with multiple processes each causing a slight tilt in the Earth's axis. This ranges from barely detectable sub-milimetre range to thousands of kilometers (over geological time - hundreds of millions of years).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to the above random fluctuations there is also the 'Chandler wobble' which is a predictable cyclic wobble in the Earth's axis, of about 9 metres, over a period of 433 days. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for human impacts, until recently I would have said that they were puny compared to natural processes. However, recent research points to significant and growing change in the Earth's rate of spin due to human induced climate change. This could have interesting 'knock-on' effects upon the spin axis. The effect is absolutely miniscule, but as the Earth's spin slows, there is likely to be further de-coupling of spin rate between the Earths crust/mantle and core which could well be an additional component to the axial wobble.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-12-18T13:55:11.303" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7116" PostTypeId="2" ParentId="7113" CreationDate="2015-12-18T14:05:58.577" Score="3" Body="&lt;p&gt;Depends upon the species. &lt;em&gt;If&lt;/em&gt; the pollen spores are large enough, &lt;em&gt;and&lt;/em&gt; of wide spatial distribution, &lt;em&gt;and&lt;/em&gt; easily recognizable, &lt;em&gt;and&lt;/em&gt; preserves well in sediments, &lt;em&gt;and&lt;/em&gt; of distinctive age range (geologically), then it could be used. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There have been mistakes in the past where modern pollen collected in microscopic pores in older rock, giving the illusion of rock ages much younger than they really are, so precautions against sample contamination are of paramount importance. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-12-18T14:05:58.577" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7117" PostTypeId="1" AcceptedAnswerId="7118" CreationDate="2015-12-18T15:46:15.957" Score="3" ViewCount="137" Body="&lt;p&gt;What will the earth look like when the continents recollide? What will the climate be like? Assume global warming has been taken care of.&lt;/p&gt;&#xA;" OwnerUserId="785" LastEditorUserId="111" LastEditDate="2015-12-18T19:04:41.447" LastActivityDate="2015-12-18T19:04:41.447" Title="Future super-continent" Tags="|climate|plate-tectonics|earth-history|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7118" PostTypeId="2" ParentId="7117" CreationDate="2015-12-18T16:47:42.383" Score="3" Body="&lt;p&gt;There are a couple of very cool animations on YouTube of the future supercontinent: Pangea Proxima. One is by &lt;a href=&quot;http://www.scotese.com/&quot; rel=&quot;nofollow&quot;&gt;Christopher Scotese&lt;/a&gt; (&lt;a href=&quot;https://www.youtube.com/watch?v=2It3ETk2MGA&quot; rel=&quot;nofollow&quot;&gt;video&lt;/a&gt;) and the other is by Algol (&lt;a href=&quot;https://www.youtube.com/watch?v=bQywDr-btz4&quot; rel=&quot;nofollow&quot;&gt;YouTube&lt;/a&gt; or also a &lt;a href=&quot;http://davidson16807.github.io/3billionyears/#&quot; rel=&quot;nofollow&quot;&gt;longer animation&lt;/a&gt; with a longer history). The &lt;a href=&quot;http://www.scotese.com/&quot; rel=&quot;nofollow&quot;&gt;PALEOMAP Project&lt;/a&gt; page contains a fair amount of information as to how they estimate the evolution. With regard to the future climate, that is a really tough question that I don't feel qualified to answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, even though it does not include the future supercontinent, I really like the &lt;a href=&quot;http://www.hhmi.org/biointeractive/earthviewer-online-and-downloadable-version&quot; rel=&quot;nofollow&quot;&gt;EarthViewer&lt;/a&gt; interactive tool. It has lots of information and it is very intuitive to use.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-12-18T16:47:42.383" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7119" PostTypeId="1" CreationDate="2015-12-19T07:06:47.533" Score="14" ViewCount="4687" Body="&lt;p&gt;I know that St. Elmo's Fire is a form of plasma that occurs during thunderstorms that is similar to lightning because it is formed by a difference in charges.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But why isn't it dangerous if St. Elmo's Fire is around you?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For one, the fact that there is a charge difference usually means an electric shock, whether that is a tiny bit of static electricity from touching metal or a lightning strike. Yet St. Elmo's Fire is caused by a charge difference but doesn't give you an electric shock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also if there is a charge difference around you, lightning is more likely to strike you, even if you are as low as you can be. This can lead to heart problems such as tachycardia, fibrillation, or asystole. It can also cause uncontrollable muscle movements which itself can be dangerous because if your muscles are out of control you can end up anywhere. Muscles being out of control can also mean things like vomiting, lots of mechanical digestion, high blood pressure and more from involuntary muscles being out of control. In any case it is dangerous to have voluntary or involuntary muscles out of control. It can also cause nervous system problems, in particular excitation toxicity from positive charges continously reaching neurons until they don't send a signal. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So with all the health problems that can result and the difference in charges itself without an electric shock, why is St. Elmo's Fire not dangerous?&lt;/p&gt;&#xA;" OwnerUserId="1388" LastActivityDate="2019-08-29T18:35:45.990" Title="St. Elmo's Fire not dangerous?" Tags="|meteorology|thunderstorm|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7120" PostTypeId="2" ParentId="4384" CreationDate="2015-12-21T03:05:48.120" Score="3" Body="&lt;p&gt;Some new evidence has come out, with the investigated are extending from 35S to 90S. Some things were different than in the study from 2007. The Southern Ocean played an important role in carbon sink. Compared to this domain, fishing activities are much in the low latitude. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dKa8e.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dKa8e.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mikaloff-Fletcher, SE, 2015, Science&lt;/p&gt;&#xA;" OwnerUserId="5029" LastEditorUserId="111" LastEditDate="2015-12-21T03:15:58.610" LastActivityDate="2015-12-21T03:15:58.610" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7121" PostTypeId="1" CreationDate="2015-12-22T12:08:16.560" Score="6" ViewCount="2144" Body="&lt;p&gt;The National Weather Service (NWS) makes the results from its Global Forecast System model (GFS) available for download as GRIB2 files.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While accessing current (or recent) forecasts is straight-forward, I am looking for the archived forecasts over at least the last year, better multiple years back for the purpose of statistical analysis of predominant weather patterns in certain areas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anybody know how to access this information?&lt;/p&gt;&#xA;" OwnerUserId="5032" LastEditorUserId="111" LastEditDate="2015-12-25T01:57:56.923" LastActivityDate="2015-12-28T18:12:22.353" Title="Historical NWS GFS forecast data" Tags="|meteorology|weather-forecasting|atmosphere-modelling|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7122" PostTypeId="2" ParentId="7121" CreationDate="2015-12-22T16:24:47.917" Score="3" Body="&lt;p&gt;It all depends on the region you are interested on. For the North America region, you could use the North American Regional Reanalysis (&lt;a href=&quot;http://www.emc.ncep.noaa.gov/mmb/rreanl/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NARR&lt;/a&gt;). &lt;a href=&quot;https://i.stack.imgur.com/MCJsm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MCJsm.png&quot; alt=&quot;NARR footprint&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/gridded/data.narr.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NARR&lt;/a&gt; is a &quot;high resolution combined model and assimilated dataset. It covers 1979 to near present and is provided 8-times daily, daily and monthly&quot;. The best and easiest way to access the data is through &lt;a href=&quot;http://nomads.ncdc.noaa.gov/data.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOMADS&lt;/a&gt;. There you will find data in several different formats (netCDF, GRIB...) and it has a resolution of around 32km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If your interest is in global data, then you could try the &lt;a href=&quot;http://www.cpc.ncep.noaa.gov/products/wesley/reanalysis.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCEP/NCAR Reanalysis&lt;/a&gt;. It is a global reanalysis of the atmosphere from 1948 to the present with a resolution of 2.5 degrees. There is also the &lt;a href=&quot;http://www.cpc.ncep.noaa.gov/products/wesley/reanalysis2/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCEP/DOE reanalysis&lt;/a&gt; with a similar footprint. I think you can get both of them from NOMADS.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All these products are reanalysis (therefore not forecast) products. If your interest is in forecast products, then you can use the North American Mesoscale (&lt;a href=&quot;http://nomads.ncdc.noaa.gov/data.php#hires_weather_datasets&quot; rel=&quot;nofollow noreferrer&quot;&gt;NAM&lt;/a&gt;) product. It has a resolution of 12km and it is available through NOMADS. The model they are currently running is a version of the Weather Research &amp;amp; Forecasting - Nonhydrostatic Mesoscale Model (&lt;a href=&quot;http://www.wrf-model.org/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;WRF-NMM&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a complete list of NOAA model products available and a brief description of each in &lt;a href=&quot;http://nomads.ncep.noaa.gov&quot; rel=&quot;nofollow noreferrer&quot;&gt;the NOAA NOMADS page&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2015-12-22T16:24:47.917" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7123" PostTypeId="1" AcceptedAnswerId="7126" CreationDate="2015-12-23T05:20:44.223" Score="4" ViewCount="2510" Body="&lt;p&gt;I've noticed that in a rural area with low pollution the relative humidity is constantly lower than the humidity in a high polluted city. Is there any correlation between pollution and humidity? &lt;/p&gt;&#xA;" OwnerUserId="5034" LastActivityDate="2015-12-26T20:30:39.340" Title="Does usual city pollution have effects on relative humidity?" Tags="|humidity|air-pollution|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7126" PostTypeId="2" ParentId="7123" CreationDate="2015-12-23T16:26:14.717" Score="4" Body="&lt;p&gt;By way of &lt;a href=&quot;https://en.wikipedia.org/wiki/Humidity&quot; rel=&quot;noreferrer&quot;&gt;reference&lt;/a&gt;, &quot;humidity depends on water vaporization and condensation, which, in turn, mainly depends on temperature&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the information you have supplied in your comments. There are waters in Bucharest and forests in the suburbs, but no waters or forests where the country house is located.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From your information, Bucharest has a number of sources of atmospheric water vapour, the river that flows through it (evaporation of water) and the forests in the suburbs (transpiration of water). Additionally, motor vehicle exhausts will increase the humidity as water vapour is one of the products of the combustion of hydrocarbons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The warmer the air, the greater its capacity to hold moisture. Cities tend to be warmer than rural areas due to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Urban_heat_island&quot; rel=&quot;noreferrer&quot;&gt;heat island effect&lt;/a&gt;, which is the result of modifying land surfaces and the generation of waste heat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Humidity in the rural location will arise from evaporation of water in the soil and transpiration from crops or grasses. Such transpiration will produce less water vapour than forests. Additionally, the rural location will have significantly fewer cars producing water vapour in their exhausts. Consequently, the rural location will be less humid than the city.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason why Bucharest is more humid that the rural location has more to do with the greater availability and vaporization of water in Bucharest and the temperature of Bucharest than the amount of pollution in Bucharest.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2015-12-23T16:26:14.717" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7127" PostTypeId="1" AcceptedAnswerId="7128" CreationDate="2015-12-24T10:33:44.567" Score="-1" ViewCount="144" Body="&lt;p&gt;I just wonder why, if we ourselves could stay still in the air (or just float in the air using something such as a hot air balloon). Why doesn't the world rotate around us, allowing us to travel around the world in 24 hours?&lt;/p&gt;&#xA;" OwnerUserId="5042" LastActivityDate="2015-12-24T11:05:46.527" Title="If we could stay still in the air. Would we be travel around the entire world in 24 hours?" Tags="|geophysics|" AnswerCount="1" CommentCount="4" ClosedDate="2015-12-24T19:16:12.440" ContentLicense="CC BY-SA 3.0" />
  <row Id="7128" PostTypeId="2" ParentId="7127" CreationDate="2015-12-24T11:05:46.527" Score="3" Body="&lt;p&gt;This question belongs to physics. Objects tend to keep their velocity (direction and speed). So, if you're standing on the surface of the Earth, you're already traveling with the surface. When you take off on a hot air balloon, you keep that extra velocity due to the rotation of the Earth. The surface won't rotate underneath the balloon in flight.&lt;/p&gt;&#xA;" OwnerUserId="4650" LastActivityDate="2015-12-24T11:05:46.527" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7129" PostTypeId="1" CreationDate="2015-12-26T04:54:40.323" Score="1" ViewCount="339" Body="&lt;p&gt;Does the appearance of a tornado come from the dust or is there some characteristic of swirling wind? Additionally many experiments shows a tornado-like phenomena in a jar of water, is this possible without water?&lt;/p&gt;&#xA;" OwnerUserId="5048" LastEditorUserId="64" LastEditDate="2015-12-26T19:55:20.773" LastActivityDate="2015-12-26T20:03:38.240" Title="Appearance of Tornado" Tags="|meteorology|tornado|severe-weather|air-currents|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7130" PostTypeId="2" ParentId="7129" CreationDate="2015-12-26T06:59:59.960" Score="1" Body="&lt;p&gt;The shape of a tornado is due to the movement of air and not dust. The shape of a tornado is called a &lt;a href=&quot;https://en.wikipedia.org/wiki/Vortex&quot; rel=&quot;nofollow noreferrer&quot;&gt;vortex&lt;/a&gt;. A vortex can occur in any fluid (air or liquid) where the fluid rotates about an axis line. Vortices are examples of turbulent fluid flow (air or liquid).&lt;/p&gt;&#xA;&lt;p&gt;When vortices occur in liquids they are sometimes called whirlpools. Tornados are high energy air vortices, less energetic air vortices can occur as dust devils.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-12-26T06:59:59.960" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7131" PostTypeId="2" ParentId="7129" CreationDate="2015-12-26T20:03:38.240" Score="2" Body="&lt;p&gt;The characteristic funnel of a tornado is caused by condensed water.  A tornado is a swirling mass of air with very high vertical vorticity and a corresponding drop in pressure.  Large tornados can have pressure deficits on the order of 100 hPa, which is significant compared to synoptic horizontal pressure gradients.  The drop in pressure causes air to expand and cool and if the air is humid enough this will be accompanied by condensation and the visible appearance of the funnel.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is also worth mentioning that the visible tornado funnel does not have be in contact with the surface to be a tornado, it is only required that the surface wind circulation is connected.  In these cases the lowest part of the tornado may remain invisible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a tornado persists the funnel cloud can pick up debris (dust, dirt, plants, parts of destroyed structures, etc) and some of this debris can orbit the tornado (other parts may end up lofted into the upper troposphere or centrifuged out at low levels) adding to its visual presentation.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-12-26T20:03:38.240" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7132" PostTypeId="2" ParentId="7123" CreationDate="2015-12-26T20:30:39.340" Score="1" Body="&lt;p&gt;Relative humidity, while a nice way to gauge how air might feel (comfort), is a poor measure for comparison between different times during the day.  Of note you observe:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Every morning we have a 90-100% relative humidity here (in the city) and decreases to 60-80% later in the day.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is merely an effect of the diurnal temperature change.  Relative humidity is the ratio of the actual amount of water vapor in the air compared to the amount of water vapor needed to saturate the air.  The water vapor needed to saturate the air is a function of temperature.  Warm air needs more water vapor to be saturated than cold air.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have air with a constant mass of water vapor and vary the temperature between cold (e.g. 7 AM) and warm (e.g. the afternoon) you will have the same pattern of relative humidity you have observed -- very high in the morning and decreasing during the day.  This is a normal pattern and absent of any effects moistening or drying the air you will observe this daily pattern of relative humidity in many places.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Right now for example at 7:30Am, in Bucharest the temperature is 2C and relative humidity 93%. At the country house (90 km away), the temperature is 0C and 45% relative humidity.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Air at 2 C and 93% RH has a vapor pressure around 6.5 hPa and&#xA;air at 0 C and 45% RH has a vapor pressure around 2.8 hPa.  This means the air in Bucuresti has a little more than twice the water content of the air from your rural location.  The other answer by Fred gives some good reasons how this can arise.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A few other reasons can be the large scale wind motions and where your rural location happens to be.  Bucuresti can often be in westerly winds where some moistening occurs from flow over the Danube and further moistening within Bucuresti from rivers and lakes.  As Fred noted, urban areas tend to be warmer than rural areas so there is more capacity to hold water vapor (before saturation is reached).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You don't mention where your rural home is, but if it happens to be to the north or north west (e.g. Ploiesti, Pitesti, Buzau) then you have orographic effects from the Carpathian mountains that can dry out the air.  If flow is up and over the mountains then the air is cooled as it flows upslope (on the Transylvanian side) where it becomes cloudy and can precipitate.  This reduces the amount of water vapor in the air and as it flows downslope and warms it remains dryer.  I could give a more specific large scale flow explanation given the location of the rural house.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-12-26T20:30:39.340" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7133" PostTypeId="1" CreationDate="2015-12-27T21:30:19.427" Score="1" ViewCount="130" Body="&lt;p&gt;An ultra light plane can stay in flight up to 2400 km (the World Record) with out an engine using thermal lift. Can a huge kite like airship (not a blimp) be built to indefinitely sail in and out of the jet stream orbiting the Earth somewhat like the ship off Peter Pan? &#xA;&lt;a href=&quot;https://i.stack.imgur.com/2MoSS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2MoSS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a possible route that could be taken on this day's jet stream chart shown below.&lt;/p&gt;&#xA;" OwnerUserId="5052" LastActivityDate="2015-12-28T02:38:17.697" Title="Sailing Around the World on a Jet Stream" Tags="|weather-forecasting|air-currents|jet-stream|" AnswerCount="0" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7134" PostTypeId="2" ParentId="7136" CreationDate="2015-12-28T00:35:09.160" Score="4" Body="&lt;p&gt;Keep in mind that your jetstream map is only a schematic description. In reality you will experience shear (strong wind along jet axis, decreasing outwards). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AIbND.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AIbND.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming that the airship would drift with the wind, the shear would throw you off the jetstream and you would sooner or later been taken to convergent areas in the upper troposphere (poles, or subsidence areas at 30° N/S)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A keyword for online search would be: (Forward/Backward) Trajectories&lt;/p&gt;&#xA;" OwnerUserId="3419" LastEditorUserId="5052" LastEditDate="2015-12-29T01:36:25.323" LastActivityDate="2015-12-29T01:36:25.323" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7135" PostTypeId="2" ParentId="7136" CreationDate="2015-12-28T02:38:17.697" Score="3" Body="&lt;p&gt;In theory, maybe you could do it, but some of the jet stream loops are even tighter than in Aabaakawad's examples. The wind shear and associated turbulence in and around the jet stream's are so severe that no 'light plane' could survive. Any glider-like aircraft would break up almost immediately. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2015-12-28T02:38:17.697" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7136" PostTypeId="1" AcceptedAnswerId="7137" CreationDate="2015-12-26T23:34:40.657" Score="8" ViewCount="1313" Body="&lt;p&gt;My questions are related to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7136/first-to-sail-the-jet-stream-around-the-world&quot;&gt;a scenario discussed on Earth Science&lt;/a&gt;: A huge (heavier-than-air) kite sailing in and out of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Jet_stream&quot; rel=&quot;nofollow noreferrer&quot;&gt;jet streams&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;h3&gt;The kite:&lt;/h3&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dBmdL.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dBmdL.png&quot; alt=&quot;Kite Image&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;h3&gt;The scenario:&lt;/h3&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sUfiZ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sUfiZ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Frw9A.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Frw9A.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1IjJZ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1IjJZ.jpg&quot; alt=&quot;Earth Jet Stream model&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;h3&gt;The assumptions:&lt;/h3&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Such an airship exists and there is a person aboard, with an oxygen mask.&lt;/li&gt;&#xA;&lt;li&gt;The person is thermally insulated to keep the heat inside.&lt;/li&gt;&#xA;&lt;li&gt;The jet streams are at an altitude around 9–12 km (30,000–39,000 ft) .&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;h3&gt;The Questions:&lt;/h3&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Can a kite like the one in the picture be built to hold a person?&lt;/li&gt;&#xA;&lt;li&gt;Does the human body require pressurization as well as oxygen and insulation? &lt;a href=&quot;https://biology.stackexchange.com/questions/42436/what-is-the-maximum-altitude-where-humans-can-survive&quot;&gt;ANSWER&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Is it possible using the jet stream systems to go around the world?&lt;/li&gt;&#xA;&lt;li&gt;Can the kite fly at speeds around 80-150 km/h related to the ground?&lt;/li&gt;&#xA;&lt;li&gt;Can it sustain a free fall from its cruising altitude around 9–12 km so that the pilot can land maybe using a parachute?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;h3&gt;Possible Solutions:&lt;/h3&gt;&#xA;&lt;p&gt;&lt;strong&gt;Launch&lt;/strong&gt; Considering the altitude is up around 9–12 km then air would be thinner the size of it will have to be much larger to compensate. Use a cable and boat to lift the &lt;em&gt;UltraKite&lt;/em&gt; into the Jet Stream. At preferred altitude cable then can be mechanically released from connected drag section of the kite. A drone or balloons could replace boat and then dropped. Maybe the person could ride in the drag section.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Long Term Altitude with Ultralights Gliders on Record.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;The current 15460-meter glider height record was made with pressurized suits. But it is only 500 meters higher than Harris' previous record from 1986, which was done with just an oxygen mask. – Martin Argerami in a comment in &lt;a href=&quot;https://aviation.stackexchange.com/questions/24544/turbulent-jet-streams-on-ultralights?noredirect=1#comment62883_24544&quot;&gt;Turbulent Jet Streams on Ultralights&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;As commented by @Jan Hudec&lt;/strong&gt;: This is supposed to be a kite, but instead of being fixed to the ground as normal kite, it would have just a cabin with a braking parachute flying below the jet stream and the kite flying in the jet stream, so the whole thing would move at some speed between the slow speed of the wind at low altitude and the high speed of the jet stream.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ka0CT.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ka0CT.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" OwnerDisplayName="Jen" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2023-11-15T15:33:58.860" Title="First to Sail the Jet Stream Around the World" Tags="|meteorology|atmosphere|thermodynamics|air-currents|jet-stream|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7137" PostTypeId="2" ParentId="7136" CreationDate="2015-12-27T02:44:37.747" Score="10" Body="&lt;p&gt;As your diagram shows, the jet stream actually has two circulating components: one is &quot;around the earth&quot; (which is why the transatlantic crossing is so much faster going East than going West), while the second is more like a vortex, with a circulating flow &quot;around&quot; the main direction. This circulating flow is vertical in two places: North of the jet stream it is downwards, and South of the jet stream it is upwards.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That makes for an &quot;almost endless&quot; lift - and you could in principle hover there. It would be very uncomfortable, as the winds in that region are quite strong and turbulent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It reminds me of something I have seen near the beach: when the wind comes in from the sea, it is lifted up by the dunes; and people with hanggliders can jump off the dune, catch the wind, and literally stay in the air as long as they want (and as long as the wind stays up). If they &quot;miss&quot; the updraft when they first jump off the top of the dune, they are on the beach within five seconds; if they succeed, they fly for an hour or more. Right alongside the sea gulls who discovered the same trick many years ago. Example &lt;a href=&quot;http://farm4.static.flickr.com/3947/15625582735_99b916ba78_m.jpg&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8YbSd.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8YbSd.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't think you can prevent yourself from traveling around the globe when you do this - in other words, you would have to be content to travel in a mostly Easterly direction. I suspect (but do not know for sure) that the currents are too strong to allow you to traverse in the Westerly direction by ducking in and out of the Jet.&lt;/p&gt;&#xA;" OwnerUserId="453" OwnerDisplayName="Floris" LastActivityDate="2015-12-27T02:44:37.747" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7138" PostTypeId="2" ParentId="4309" CreationDate="2015-12-28T06:00:36.260" Score="0" Body="&lt;p&gt;According to me ITCZ is basically the trough where both the north eastern and south western winds converge or meet. You must know that winds move from high pressure to low pressure, therefore when the winds meet an area of low pressure is created on the landmass which in turn brings in winds with moisture causing rainfall. This is how the ITCZ affects the Indian monsoon.&lt;/p&gt;&#xA;" OwnerUserId="5053" LastEditorUserId="725" LastEditDate="2015-12-28T07:11:21.123" LastActivityDate="2015-12-28T07:11:21.123" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7139" PostTypeId="1" AcceptedAnswerId="7142" CreationDate="2015-12-28T17:51:40.273" Score="2" ViewCount="1195" Body="&lt;p&gt;The US Naval Observatory has a webpage that allows a user to enter a year and a latitude/longitude pair, and then produces a table of sunrise and sunset times for each day during that year at that latitude/longitude pair:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://aa.usno.navy.mil/data/docs/RS_OneYear.php&quot; rel=&quot;nofollow&quot;&gt;http://aa.usno.navy.mil/data/docs/RS_OneYear.php&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sometimes, a blank entry will appear where I would expect to see a time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, in the above webpage, if I scroll down to &quot;Form B - Locations Worldwide,&quot; enter the coordinates W074 45, N42 16, leave the &quot;time zone&quot; blank, enter &quot;2015&quot; for the year, and leave all other options at their default settings, &lt;strong&gt;I get a blank entry for May 03.&lt;/strong&gt; Can anyone help me to interpret this, or direct me to an appropriate reference?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is already a symbol for when the sun does not rise and another for when the sun does not set on a particular day.&lt;/p&gt;&#xA;" OwnerUserId="4961" LastActivityDate="2015-12-28T20:04:47.043" Title="US Naval Observatory Sunrise/Sunset Data: Blank Sunrise/Sunset Times?" Tags="|light|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7140" PostTypeId="2" ParentId="7121" CreationDate="2015-12-28T18:12:22.353" Score="2" Body="&lt;p&gt;NCDC provides &lt;a href=&quot;http://nomads.ncdc.noaa.gov/data.php#hires_weather_datasets&quot; rel=&quot;nofollow&quot;&gt;archived GFS data starting from 2004 at NOMADS&lt;/a&gt;.  They break up the data into &quot;Historical&quot; (2004-2005), &quot;Historical and near real-time&quot; (2005-2015) and analysis-only (2004-latest full month).  There are various data access methods provided on the linked web page.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2015-12-28T18:12:22.353" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7141" PostTypeId="2" ParentId="7052" CreationDate="2015-12-28T18:45:39.530" Score="2" Body="&lt;p&gt;The &lt;a href=&quot;http://www1.ncdc.noaa.gov/pub/data/normals/1981-2010/readme.txt&quot; rel=&quot;nofollow&quot;&gt;readme&lt;/a&gt; file for all the datasets has a section on units.  In this section, they describe how to interpret the numbers (which exclude decimal points in the data files).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the &quot;number of days&quot; data it says:    &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;[units are] &quot;tenths of days&quot; for the number of days per [time] above or below certain threshold, such as days above 90F. e.g., &quot;256&quot; is 25.6 days.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, you need to divide all those numbers by 10 to get the actual values.  Also, take note in the readme file of these pieces that correspond to the data file in question:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;S = standard (no more than 5 years missing and no more than 3 consecutive &#xA;    years missing among the sufficiently complete years)&#xA;&#xA;P = provisional (at least 10 years used, but not sufficiently complete to be &#xA;    labeled as standard or representative). Also used for parameter values on &#xA;    February 29 as well as for interpolated daily precipitation, snowfall, and&#xA;    snow depth percentiles. &#xA;&#xA;-9999: missing or insufficient data; values cannot be computed&#xA;-7777: a non-zero value that would round to zero, for variables bound by zero.&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="543" LastActivityDate="2015-12-28T18:45:39.530" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7142" PostTypeId="2" ParentId="7139" CreationDate="2015-12-28T20:04:47.043" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;I get a blank entry for May 03.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The Sun didn't set on Bovinia, New York on May 03 when time is expressed as Universal Time. Sunsets from May 04 to August 16 occur before sunrise. (Also note that August 16 has two sunsets.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The solution is simple: Fill in the time zone. Ignoring daylight savings time, time in Bovinia New York is offset by 5 hours from UTC.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another solution is to use a different website. There are better web services than the simple perl-based script used to generate that table.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2015-12-28T20:04:47.043" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7144" PostTypeId="2" ParentId="6665" CreationDate="2015-12-29T03:29:01.117" Score="3" Body="&lt;p&gt;There is a misconception in your assumption:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\omega = \frac{Dp}{Dt} = 0 $&lt;/span&gt; means that the mass above the air parcel stays constant.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Proof: Assume quasistatic eqn:&lt;/p&gt;&#xA;&lt;p&gt;-&lt;span class=&quot;math-container&quot;&gt;$\frac{1}{g}\, dp=\rho \, dz$&lt;/span&gt;;&lt;/p&gt;&#xA;&lt;p&gt;apply operator of horizontal mean: &lt;span class=&quot;math-container&quot;&gt;$\overline{(\cdot)}= \frac{\int (\cdot)  \, dxdy}{\int dxdy}=\frac{\int (\cdot)  \, dA}{\Delta A}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;-&lt;span class=&quot;math-container&quot;&gt;$\frac{1}{g}\, \overline{dp} \, \Delta A=\rho \, dxdydz= \rho dV = dM$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Integrating between arbitrary pressure levels gives mass between those levels.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;(1) You correctly estimated &lt;span class=&quot;math-container&quot;&gt;$\partial p_s/\partial y &amp;lt;0 $&lt;/span&gt; in order to have wind to the north, but&lt;/p&gt;&#xA;&lt;p&gt;(2) you also set &lt;span class=&quot;math-container&quot;&gt;$\partial p_s/\partial t =0 $&lt;/span&gt; in your derivation (to replace total derivative with advection of &lt;span class=&quot;math-container&quot;&gt;$p_s$&lt;/span&gt;). This means that the pressure field is constant in time.&lt;/p&gt;&#xA;&lt;h1&gt;Result&lt;/h1&gt;&#xA;&lt;p&gt;(1) and (2) yield to lower pressure in the north (&lt;span class=&quot;math-container&quot;&gt;$dp_s/dy&amp;lt;0$&lt;/span&gt;) and decreasing surface pressure following the parcel (&lt;span class=&quot;math-container&quot;&gt;$dp_s/dt&amp;lt;0$&lt;/span&gt;)&lt;/p&gt;&#xA;&lt;p&gt;This means that an air parcel has to descend (in terms of &lt;span class=&quot;math-container&quot;&gt;$\sigma$&lt;/span&gt;) in order to satisfy the condition of constant mass lying over it (&lt;span class=&quot;math-container&quot;&gt;$\omega = \frac{Dp}{Dt} = 0 $&lt;/span&gt;):&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$d\sigma/dt = a \, dp/dt- b\, dp_s/dt$&lt;/span&gt;; (with a,b const.)&lt;/p&gt;&#xA;&lt;p&gt;=&amp;gt; &lt;span class=&quot;math-container&quot;&gt;$d\sigma/dt &amp;gt;0$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;h1&gt;Example&lt;/h1&gt;&#xA;&lt;p&gt;If your parcel starts at 950 hPa, travels to north with falling surface pressure, condition &lt;span class=&quot;math-container&quot;&gt;$\omega=0$&lt;/span&gt; means it stays at 950 hPa, but with (1) surface pressure drops to 950 hPa as the parcel continues north and the parcel miraculously is found to be at ground level.&lt;/p&gt;&#xA;&lt;h1&gt;Conclusion&lt;/h1&gt;&#xA;&lt;p&gt;As &lt;span class=&quot;math-container&quot;&gt;$\sigma$&lt;/span&gt; depends on pressure and surface pressure, so does its time derivative.&lt;/p&gt;&#xA;" OwnerUserId="3419" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2015-12-29T03:29:01.117" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7145" PostTypeId="1" AcceptedAnswerId="12657" CreationDate="2015-12-29T17:06:58.873" Score="3" ViewCount="3045" Body="&lt;p&gt;I'm guessing that falling rain equilibrates fairly quickly to the temperature of the air it's falling through. However, it isn't always at the exact same temperature, which is why we can get the lovely phenomena called &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Freezing_rain&quot; rel=&quot;nofollow&quot;&gt;freezing rain&lt;/a&gt;&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How far below the ground-level air temperature can rain be? &lt;/p&gt;&#xA;" OwnerUserId="534" LastActivityDate="2017-11-13T08:35:26.407" Title="By how much can rain temperature vary from the ground-level air temperature?" Tags="|temperature|rain|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7146" PostTypeId="1" CreationDate="2015-12-29T21:03:35.433" Score="6" ViewCount="89" Body="&lt;p&gt;&lt;a href=&quot;https://books.google.com/books?hl=en&amp;amp;lr=&amp;amp;id=a57vAwAAQBAJ&amp;amp;oi=fnd&amp;amp;pg=PP1&amp;amp;ots=M3D2ZieVVS&amp;amp;sig=e9Hg4FilmNglEZLObK46vCjWmsE#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;noreferrer&quot;&gt;Hannah's text on the biology of climate change&lt;/a&gt; appears to suggest that forcing due to changes in obliquity can act in opposite ways in Antarctic waters.  On one hand, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Low obliquity brings cool summers to both hemispheres, which favors ice buildup in the north and intensified circumpolar current in the south.  The intensification of the circumpolar current reduces upwelling of $\ce{CO2}$-rich water.  The reduction in atmospheric $\ce{CO2}$ cools the planet...&quot; &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;On the other hand, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;high obliquity results in warmer summers in both hemispheres.  This begins to melt the continental ice sheets in the north, whereas in the south it intensifies circumpolar currents and winds, pumping $\ce{CO2}$-rich water to the surface and warming.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;How can &quot;intensified&quot; ACC both increase and decrease upwelling?  How does this &quot;intensification&quot; occur, that is what is the linkage between warmer or cooler Antarctic summers and the intensification?  Apparently ocean - atmosphere $\ce{CO2}$ exchange is important here but the fertilization effect of upwelling is not?&lt;/p&gt;&#xA;" OwnerUserId="5064" LastEditorUserId="111" LastEditDate="2015-12-30T01:36:05.027" LastActivityDate="2015-12-30T01:36:05.027" Title="Relationship between obliquity, antarctic circumpolar current, and atmospheric $\ce{CO2}$" Tags="|atmosphere|climate-change|oceanography|ocean-currents|antarctic|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7147" PostTypeId="1" AcceptedAnswerId="7148" CreationDate="2015-12-29T22:37:05.157" Score="4" ViewCount="997" Body="&lt;p&gt;I have three parameters for a particular location, namely: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Ozone:- A numerical value representing the columnar density of total atmospheric ozone at the given time in Dobson units&lt;/li&gt;&#xA;&lt;li&gt;Elevation: The elevation of the location in meters.&lt;/li&gt;&#xA;&lt;li&gt;Cloud Cover: A numerical value between 0 and 1 (inclusive) representing the percentage of sky occluded by clouds.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Is it possible to calculate the UV index of that location using this information? &lt;/p&gt;&#xA;" OwnerUserId="5065" LastEditorUserId="543" LastEditDate="2015-12-30T05:49:49.190" LastActivityDate="2015-12-30T05:49:49.190" Title="How is a UV Index calculated?" Tags="|meteorology|climate|clouds|ozone|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7148" PostTypeId="2" ParentId="7147" CreationDate="2015-12-30T01:15:12.437" Score="3" Body="&lt;p&gt;The calculation of UV indices requires some effort.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because different wavelengths of UV radiation have different effects on skin, to calculate the UV index you need to apply &quot;McKinlay-Diffey&quot; weighting factors to various wavelength components of UV radiation and then integrate (sum) those results and then divide by 25.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The procedure does not use ozone readings but it does use elevation and cloud cover.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following two references list the procedure required:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://serc.si.edu/labs/photobiology/UVIndex_calculation.aspx&quot; rel=&quot;nofollow&quot;&gt;Smithsonian Environmental Research Center&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.epa.gov/sunsafety/calculating-uv-index-0&quot; rel=&quot;nofollow&quot;&gt;US EPA&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.esrl.noaa.gov/gmd/grad/neubrew/docs/UVindex.pdf&quot; rel=&quot;nofollow&quot;&gt;NOAA-EPA Brewer Network&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="725" LastEditDate="2015-12-30T04:09:09.550" LastActivityDate="2015-12-30T04:09:09.550" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7149" PostTypeId="1" AcceptedAnswerId="7150" CreationDate="2015-12-30T01:30:11.360" Score="5" ViewCount="705" Body="&lt;p&gt;Most early examples of tidal energy generators used &lt;a href=&quot;https://en.wikipedia.org/wiki/Tidal_barrage&quot; rel=&quot;nofollow&quot;&gt;barrages&lt;/a&gt; (damns) to generate electricity (&lt;a href=&quot;https://en.wikipedia.org/wiki/Rance_Tidal_Power_Station&quot; rel=&quot;nofollow&quot;&gt;La Rance&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Kislaya_Guba_Tidal_Power_Station&quot; rel=&quot;nofollow&quot;&gt;Kislaya Guba&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Annapolis_Royal_Generating_Station&quot; rel=&quot;nofollow&quot;&gt;Annapolis Royal&lt;/a&gt;). Meanwhile, a lot of newer projects use rotary blades in the tidal flow (like windmill blades), resulting in an installation that looks like an underwater wind farm. Examples of such projects are: &lt;a href=&quot;http://fundyforce.ca/&quot; rel=&quot;nofollow&quot;&gt;FORCE&lt;/a&gt; (Fundy Ocean Research Center for Energy), &lt;a href=&quot;https://en.wikipedia.org/wiki/SeaGen&quot; rel=&quot;nofollow&quot;&gt;SeaGen&lt;/a&gt;, &lt;a href=&quot;http://www.tidalstream.co.uk/&quot; rel=&quot;nofollow&quot;&gt;TidalStream&lt;/a&gt;...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While some have claimed that the environmental effects of these new systems are much less severe, the fact is that tidal current technology is relatively new and has been applied in only a few sites. The environmental impacts seem to be based on hypothesis, modeling and simplified lab experiments, but my questions are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;What are these environmental effects?&lt;/li&gt;&#xA;&lt;li&gt;How much are the local currents affected by these structures?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2015-12-31T16:06:56.657" LastActivityDate="2015-12-31T16:06:56.657" Title="What are the effects of underwater &quot;windmills&quot;?" Tags="|ocean|ocean-currents|tides|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7150" PostTypeId="2" ParentId="7149" CreationDate="2015-12-30T08:14:11.720" Score="6" Body="&lt;p&gt;As you have noted, this technology is new, and so far only small numbers of experimental tidal energy converters (TECs) have been deployed. For this reason, little has been possible in the way of measurement, and so as you note, all estimates are based on models or other means of prediction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer the second question first - how much the currents are affected depends how much of the energy you remove. Since the whole point of TECs is to remove energy from the flow, there must be some effect on currents. &lt;a href=&quot;http://dx.doi.org/10.1098/rspa.2005.1494&quot;&gt;Garrett &amp;amp; Cummins (2005)&lt;/a&gt; built a simple analytic model of a channel between two large basins (which reflects many tidal energy scenarios) and showed that if all other considerations (e.g. navigation, engineering practicality) are ignored then the maximum power that may be extracted from the channel is obtained when its flow rate is reduced by approximately two thirds. However, this scenario is unlikely to ever be obtained, and the real limit on energy extraction at a given site (if not an economic limit) will probably be determined by what level of environmental effects are deemed to be acceptable. The relationship between power extracted and effect on the flow is not a simple one, and in most cases a significant proportion of the available power could be obtained with a relatively small change to the local currents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A number of modelling studies have been made of more realistic scenarios for early deployment (e.g. &lt;a href=&quot;http://dx.doi.org/10.1016/j.renene.2011.07.005&quot;&gt;Admadien et al 2012&lt;/a&gt;). These typically predict local changes to current speeds of up to 30%, which fade after a few km. Typically there is a decrease in the flow speed in line with the TECs, and an increase to either side of the farm/array, as some of the flow diverts around the added impedence. Effects on &lt;em&gt;residual&lt;/em&gt; velocity (i.e. that which is left in the long term when the tidal cycles are averaged out over a period of time), which is relevant to sediment transport processes, are predicted up to at least 15km away.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some baroclinic modelling (&lt;a href=&quot;http://dx.doi.org/10.1007/s12237-013-9684-2&quot;&gt;Yang &amp;amp; Wang 2013&lt;/a&gt;) has suggested increased mixing, and thus decreased stratification, as a result of the turbulence introduced by TECs. It is also conceivable that in other scenarios, stratification might be increased as a result of reduced flow speeds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Physical effects, then, are likely to include direct effects on current speed, sediment, and stratification.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The obvious possible biological effect is from collisions. This is not my field, but as I understand it no effect is likely on small fish populations from collisions, although individuals may be affected. Collision risk for large animals (e.g. sharks and marine mammals)  and for diving birds is a topic of active research, and is likely (especially for mammals) to depend on their behaviour around the devices. No large animal collisions have been reported on any of the prototypes undergoing testing so far.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good review of possible effects on benthic organisms is provided by &lt;a href=&quot;http://dx.doi.org/10.1016/j.ocecoaman.2010.10.036&quot;&gt;Shields et al (2011)&lt;/a&gt;. These may include,&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Direct disruption of seabed habitats by physical interference, e.g. from moorings&lt;/li&gt;&#xA;&lt;li&gt;Disruption of ecological niches: Some organisms have evolved to survive in areas where others cannot - e.g. high current speed environments. Changes in seabed conditions, e.g. from greater or lesser current speeds, may cause them to be out-competed by other species that can then settle there.&lt;/li&gt;&#xA;&lt;li&gt;Similarly, changes to sediment distribution represent changes to seabed habitats.&lt;/li&gt;&#xA;&lt;li&gt;Alteration of flow patterns could have implications for species with a dispersive juvenile stage (e.g. larvae that rely on currents to spread) or those that rely on current flow for nutrient or waste transport.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="39" LastActivityDate="2015-12-30T08:14:11.720" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7151" PostTypeId="1" CreationDate="2015-12-30T09:09:18.083" Score="9" ViewCount="207" Body="&lt;p&gt;I'm looking to demonstrate the rotational behaviour of swirling storms with a numerical simulation. So far it includes pressure-gradient, Coriolis acceleration, frictional forces and the acceleration due to gravity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a non-inertial frame of reference (surface of the Earth), $(O', \vec{x'}, \vec{y'}, \vec{z'})$, $\vec{x'}$ points south, $\vec{y'}$ points eastward and $\vec{z'}$ upward. I've found that the acceleration of air masses is expressed as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\ddot{x'}=-\cfrac{1}{\rho}\cfrac{\partial p}{\partial x'} - \nu \dot{x'} + 2\omega\sin(\lambda)\dot{y'}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\ddot{y'}=- \cfrac{1}{\rho}\cfrac{\partial p}{\partial y'} - \nu \dot{y'} -2\omega(\sin(\lambda)\dot{x'} + \cos(\lambda)\dot{z'})$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\ddot{z'}=- g - \cfrac{1}{\rho}\cfrac{\partial p}{\partial z'} - \nu \dot{z'} + 2\omega\cos(\lambda)\dot{y'}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where the last terms are the deflections due to the Coriolis effect, the middle ones friction forces and the first ones pressure-gradient forces. $g$ is the acceleration due to gravity ($g=9.8 \ m.s^{-2}$).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would work in 2 dimensions since my initial conditions (pressure maps) are given for a specific altitude. But then I would ignore some terms of the Coriolis and gravity, and many other effects I bet. I can go for a 3d description of the phenomenon, but it might be too difficult to deal with a collection of pressure maps at different altitudes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Questions:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Is the set of equations physically correct to model accurately the spiral-ish rotation of hurricanes? If not, what are the other forces that would be worth adding?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;I'm doing a numerical simulation, and I want to test it with pressure maps. The first thing I've done was removing the terms that act in the $\vec{z'}$ direction since my initial conditions (pressure maps) are given for a specific altitude. Is this approximation still correct to achieve my goal?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;In addition to question 2, if the model should rather be described in a 3 dimensional coordinate system, it might be too difficult to deal with a collection of pressure maps at different altitudes, is it?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I'm definitely not an expert and my readings in the subject didn't help.&lt;/p&gt;&#xA;" OwnerUserId="4650" LastEditorUserId="725" LastEditDate="2016-01-24T04:37:37.140" LastActivityDate="2016-01-24T04:37:37.140" Title="Modeling swirling storms" Tags="|atmosphere-modelling|numerical-modelling|severe-weather|" AnswerCount="0" CommentCount="7" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7152" PostTypeId="2" ParentId="7097" CreationDate="2015-12-30T09:13:00.070" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;It is also quite striking for those of us who are not climate&#xA;scientist that the amount of warming we are talking about is on a&#xA;scale (0-2 C) that is much smaller than the temperature variation we&#xA;might experience during a time scale as short as a day or distance&#xA;scales as short as a few hundred of kilometers.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;TLDR, but here goes:&lt;/p&gt;&#xA;&lt;p&gt;There's a few factors to consider regarding the relatively tiny 2 degrees C and I'm not sure how to explain this without being long, but obviously you're correct, we hardly notice a 2 degree change ourselves.   But if you look at the total energy of Earth you can get a slightly better picture.&lt;/p&gt;&#xA;&lt;p&gt;The numbers below are only approximations but should be close enough to give an idea of how the trapped heat plays in the Earth's atmosphere and oceans.&lt;/p&gt;&#xA;&lt;p&gt;The sun shines on the Earth about 1.8x10&lt;sup&gt;17&lt;/sup&gt; Joules per second, or about 5.6x10&lt;sup&gt;24&lt;/sup&gt; Joules per year.   &lt;a href=&quot;http://helios.gsfc.nasa.gov/qa_sun.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;.   Remember that number, I'll reference it a few times.&lt;/p&gt;&#xA;&lt;p&gt;The rough division is about 48% of that hits the surface, 23% is absorbed in the atmosphere, 29% is reflected back into space.  &lt;a href=&quot;http://earthobservatory.nasa.gov/Features/EnergyBalance/page4.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;.  Now, because the Earth is in largely in a stable equilibrium where energy in roughly equals energy out, the Earth radiates about the equivalent of 71% of that 5.6x10&lt;sup&gt;24&lt;/sup&gt; Joules per year that the sun shines on it, the other 29% being reflected.&lt;/p&gt;&#xA;&lt;p&gt;This will be obvious to some but I'll mention it anyway.   Global warming has nothing to do with the sun giving the Earth more energy.   It has to do with the Earth radiating less energy into space, at least until the Earth warms enough for a new equilibrium to re-stabilize the energy in = energy out.   Raising the concentration of greenhouse gas changes the equilibrium of heat transfer.   It's the same principal as putting on a sweater.&lt;/p&gt;&#xA;&lt;p&gt;Using the same link as above, 59 of that 71% radiates from Earth's upper atmosphere and the remaining 12% from the surface.  For greenhouse gas driven climate change to work, the only way that can work is that the 59% needs to drop (OK, not the only way, you can also play with albedo).  But heat is trapped in the lower atmosphere, the upper atmosphere cools and the 59% drops a little lower.   Cloud cover and changes in Albedo such as snow cover, ocean cover and green vs desert are factors too, (the 29% mentioned above), but that gets enormously complicated, and beyond the scope of anything I can try to explain, so I'm going to ignore that for now and just look at the 59% of the 5.6x10&lt;sup&gt;24&lt;/sup&gt; Joules per year.&lt;/p&gt;&#xA;&lt;p&gt;Thermal radiation increases at roughly the 4th power of the temperature, so if we use the average temperature on Earth at about 288 Kelvin and add 2 degrees to that, the radiation difference between 288 Kelvin and 290 Kelvin using the 4th power rule is a 2.8% increase, or an increase from 12% to 12.34% of the 5.6x10&lt;sup&gt;24&lt;/sup&gt;.   To keep the energy balance consistent, when a new equilibrium is reached, the 59% drops to 58.66% with 0.34% being &amp;quot;new heat&amp;quot; due to the additional greenhouse gas.   This change presumably has already happened.  In fact, today, the heat balance is out of equilibrium which is why the Earth is warming.   The Earth is taking in more heat than it's giving back into space.&lt;/p&gt;&#xA;&lt;p&gt;0.34% of 5.6x10&lt;sup&gt;24&lt;/sup&gt; = 1.9x10&lt;sup&gt;22&lt;/sup&gt; Joules.  By comparison, the combined energy use of all man-kind is about 1/40th of that, or about 5x10&lt;sup&gt;20&lt;/sup&gt;th Joules.  &lt;a href=&quot;https://en.wikipedia.org/wiki/Orders_of_magnitude_%28energy%29&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;.   So, from a human perspective it's an enormous amount of energy but to the something the size of the Earth it's quite small.   Needless to say, the 0.34% estimate is pretty rough, so take the numbers below with some flexibility, but they're also, at least somewhat in the range.&lt;/p&gt;&#xA;&lt;p&gt;Second, we have to consider where the heat is going.   By most estimates, more than 90% of this goes into the oceans and about 90% or a bit more of the heat is going into the oceans with some melting ice, some going into the ground and melting tundra and only a small percentage going into the atmosphere where surface temperatures are calculated.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://skepticalscience.com/graphics.php?g=12&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;, &lt;a href=&quot;http://e360.yale.edu/feature/how_long_can_oceans_continue_to_absorb_earths_excess_heat/2860/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt; and &lt;a href=&quot;http://www.scientificamerican.com/article/mystery-of-ocean-heat-deepens-as-climate-changes/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt; (The first mentions a very specific 93.4% into the oceans and 2.3 into the Atmosphere.   The last 2 mention &amp;quot;more than 90%&amp;quot; and &amp;quot;about 90%&amp;quot;, so there might be some uncertainty on the precise ratio and I'm going to round up to 3%.   Feel free to re-run the numbers with 2.3%, 4%, whatever you like.&lt;/p&gt;&#xA;&lt;p&gt;3% of 1.9x10&lt;sup&gt;22&lt;/sup&gt; = 5.8x10&lt;sup&gt;20&lt;/sup&gt;  (not a typo, it's actually 1.93)&lt;/p&gt;&#xA;&lt;p&gt;So the atmosphere, by rough estimates, adds about 5.8x10&lt;sup&gt;20&lt;/sup&gt; Joules of energy as a result of the increase in CO&lt;sub&gt;2&lt;/sub&gt;.  So, to estimate the expected warming from that amount of energy:&lt;/p&gt;&#xA;&lt;p&gt;The mass of the Atmosphere is about 5.1x10&lt;sup&gt;21&lt;/sup&gt; grams.  &lt;a href=&quot;http://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;.&#xA;About 4.2 joules can heat 1 gram of water 1 degree C.  &lt;a href=&quot;https://en.wikipedia.org/wiki/Calorie&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;, and the specific heat of the atmosphere is about 1/4.1 that of water, &lt;a href=&quot;http://www.iun.edu/%7Ecpanhd/C101webnotes/matter-and-energy/specificheat.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;.   Of ocean water, slightly lower, I'm going to estimate 1/4.0&lt;/p&gt;&#xA;&lt;p&gt;so, doing the maths: (4.0/4.2)x(5.1x10&lt;sup&gt;21&lt;/sup&gt;/5.8x10&lt;sup&gt;20&lt;/sup&gt;), my roughest of calculations says that we'd need about 9 years of trapped heat to warm the atmosphere 1 degree C.   If we use skeptical sciences 2.3% number, that ups it to about 11.5 years, and both estimates are obviously too aggressive.  The observed surface temperature warming is closer to 1 degree every 40-50 years, give or take, though the warming on land is faster than the warming over water.   But my estimate can't help but be quite rough.  It excludes albedo and cloud formation entirely, which is important, but trying to calculate is hugely complex and far above my pay-grade.   It's difficult to calculate the effects of clouds on global warming even with super-computers.&lt;/p&gt;&#xA;&lt;p&gt;Now, obviously ocean currents, dictate varying amounts of heat exchanged between the ocean and the atmosphere, so one year to the next can vary by significantly more than 1/9th of 1 degree, but that's movement of heat, not new heat added to the system.&lt;/p&gt;&#xA;&lt;p&gt;Now if I calculate how long it would take to heat the oceans, and as I understand it, the deep oceans aren't warming, but the surface and sometimes called &amp;quot;mid-oceans&amp;quot; or mid-depth are warming, (articles &lt;a href=&quot;http://www.theguardian.com/environment/climate-consensus-97-per-cent/2015/jul/20/oceans-warming-faster-than-climate-models-predicted&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;http://news.nationalgeographic.com/news/2013/10/131031-climate-ocean-temperatures-years/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Using the numbers above, for 1 mile deep using with the estimate of about 33 times the heat going into the oceans than into the atmosphere, reapplying the specific heat of water to atmosphere ratio of 4 to 1 and estimating the mass of 1 mile of ocean water equivalent to about 160 atmospheres, adjusting for 71% of surface cover, it comes to a rough estimate of 124 years for my very rough heat trapping estimate to warm 1 mile of oceans about 1 degree C.   I couldn't find any precise warming in the oceans, but 1 degree of warming, 1 mile deep in 124 years sounds roughly in the neighborhood of what the experts expect. (I think).&lt;/p&gt;&#xA;&lt;p&gt;So, long story short, while local temperature can change significantly over different parts of the day, global average temperature isn't nearly so easily changed.  On a single day (using numbers above), the Earth gets 71% of 5.6x10&lt;sup&gt;24&lt;/sup&gt;/365 or about 1.1x10&lt;sup&gt;22&lt;/sup&gt; joules, and an amount quite close to that radiates away from the earth every day too.   Based on my very rough estimate, the difference between heat the Earth takes in and heat the Earth radiates is about 0.3%.  On individual days you might get a fair bit bigger than a 0.3% difference, but there's still not enough heat added by 1 day of sunlight to significantly change the Earth's global average temperature.&lt;/p&gt;&#xA;&lt;p&gt;Now, obviously, the Earth's surface warms measurably under daylight but that's because 48% of the suns energy reaches the surface directly and the heat is localized, and while 1/2 of the Earth's surface warms the other half cools, so it tends to average out.    There's insufficient energy in sunlight to make much change to global average temperature over a short period of time.&lt;/p&gt;&#xA;&lt;p&gt;With that in mind, the 2 degrees that the IPCC discusses, which includes ocean heat trapping, is quite significant.    It more likely works out to about 3 degrees on land, 1.5 degrees over water, with rising oceans due to both thermal expansion and melting ice.   Warmer oceans means bigger hurricanes.   It's easy to say &amp;quot;2 degrees won't matter&amp;quot;, but the models say it actually might.   It's a pretty significant variation.  It also takes quite a bit of time for the 40% increase in CO&lt;sub&gt;2&lt;/sub&gt; to create that much warming, which is why the projections of 2 degrees warming go out to about 2100.&lt;/p&gt;&#xA;&lt;p&gt;Another way to point out lack of global temperature variation is to look at the charts for global average temperature.   while, I couldn't find any charts for daily variation of average global temperatures, I found some monthly variation charts &lt;a href=&quot;http://data.giss.nasa.gov/gistemp/graphs_v3/Fig.C.txt&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.  &lt;a href=&quot;http://data.giss.nasa.gov/gistemp/graphs_v3/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;.   Assuming the monthly averages have gotten more accurate in recent decades, The average global temperature change month to month is about 0.13 degrees C over land and about 0.095 degrees C over oceans since 1980, with the largest month to month variation about 0.47 degrees C over land 0.36 over oceans.  There's probably some rounding errors in there, but there's clearly a degree of consistency to global average surface temperature and even more consistency to surface temperature over the oceans, and that's exactly what we should expect, having looked at the heat in and heat out.&lt;/p&gt;&#xA;&lt;p&gt;Local affects are driven by circulation, but circulation is simply the moving of heat from one place to another.  Circulation isn't the creation of heat but the behavior of heat and differences in air pressures and it doesn't measurably add any heat to the system.&lt;/p&gt;&#xA;&lt;p&gt;Corrections to my too long answer welcome.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2470" LastEditDate="2021-02-24T22:59:42.283" LastActivityDate="2021-02-24T22:59:42.283" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="7153" PostTypeId="1" CreationDate="2015-12-30T16:53:26.730" Score="2" ViewCount="450" Body="&lt;p&gt;Unless there's a twin star to our sun in which case axial precession might be an illusion the Earth's wobble won't effect the total amount of energy received from the sun as is expected from increased ellipticity, but will effect the amount of sun's energy to the Northern and Southern hemispheres in a cyclical 26000 (and diminishing) year period with periodic further exacerbations caused by variations in tilt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How has Precession and variations in tilt been factored into the weather change model if at all?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a side question: On the Salisbury Plain 6500 yrs ago according to wobble theory the East-West alignment going by the apparent motion of the sun across the sky must have been different to today. Can anyone tell me how to calculate the difference in respect to Grid North  please? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Background&lt;/strong&gt;:&lt;br /&gt;&#xA;I'm building a picture of Neolithic Britain and want to know the orientation of East-West in this time period to check for orientation practices if any. The particular time period I'm interested in lies about half way along the Axial Precession's swing so I'm interested to know A) Whether the axial precession exists or not and B) How the theory is in agreement with the weather patterns for the last 24000 yrs on Salisbury Plain. &lt;/p&gt;&#xA;" OwnerUserId="5069" LastEditorUserId="5069" LastEditDate="2016-01-05T11:56:35.123" LastActivityDate="2016-01-09T07:57:23.590" Title="How will axial precession affect the weather in the northern hemisphere (UK latitudes)?" Tags="|meteorology|planetary-science|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7154" PostTypeId="1" CreationDate="2015-12-30T20:31:51.983" Score="1" ViewCount="245" Body="&lt;p&gt;In all the documentaries I've seen regarding the Arctic or anyplace close to it, like Alaska or Siberia, they simply say that summer in the Arctic is &quot;short&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But how short is short?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How long does the sun refuse to set in the land of the midnight sun?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastActivityDate="2015-12-30T20:31:51.983" Title="How Short IS The Arctic Summer?" Tags="|seasons|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="7157" PostTypeId="1" CreationDate="2015-12-31T11:11:51.853" Score="8" ViewCount="111" Body="&lt;p&gt;I am searching for a database (a free one would be great) that would give me, for any chosen rectangular area on earth, historic data about pressure, sea water temperature, wind (including both speed and direction) and in general as much weather-related information as possible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there such a thing?&lt;/p&gt;&#xA;" OwnerUserId="418" LastEditorDisplayName="user1066" LastEditDate="2015-12-31T11:13:56.480" LastActivityDate="2015-12-31T11:13:56.480" Title="Worldwide weather maps database" Tags="|meteorology|weather-forecasting|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7158" PostTypeId="1" AcceptedAnswerId="7160" CreationDate="2015-12-31T20:49:37.867" Score="6" ViewCount="935" Body="&lt;p&gt;With the current instruments in hand, how accurately can we predict tsunamis? Please consider me as a novice with only basic information how tsunamis are formed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has there ever been a successful evacuation in history in regards to incoming &lt;em&gt;death waves&lt;/em&gt;?&lt;/p&gt;&#xA;" OwnerUserId="5074" LastEditorUserId="595" LastEditDate="2016-01-02T16:30:52.027" LastActivityDate="2016-01-02T17:52:35.973" Title="How accurately can a tsunami be predicted? Have there been any successful evacuations?" Tags="|measurements|tsunami|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7160" PostTypeId="2" ParentId="7158" CreationDate="2016-01-02T02:40:11.367" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Tsunami#Warnings_and_predictions&quot; rel=&quot;nofollow noreferrer&quot;&gt;The ability to predict depends on the cause of the tsunami&lt;/a&gt;. Earthquakes can't be predicted, so a tsunami caused by an earthquake can't be predicted. A meteor can be tracked for a considerable time in space before sticking earth so a tsunami caused by an meteor strike can be predicted. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is also the possibility of a &lt;a href=&quot;https://en.wikipedia.org/wiki/Tsunami_warning_system&quot; rel=&quot;nofollow noreferrer&quot;&gt;tsunami early warning system&lt;/a&gt;. There are currently sensors in some parts of the ocean which can detect a tsunami before &quot;landfall&quot; and provide an early warning system. Think of it somewhat like tracking a hurricane which generally takes a lot longer to reach land. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a &lt;a href=&quot;http://hvo.wr.usgs.gov/observatory/hvo_history.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;webpage&lt;/a&gt; it was reported that &quot;in 1933 HVO [Hawaiian Volcano Observatory] used seismograms to predict (accurately) the arrival of a tsunami from a distant earthquake, and people in low-lying areas of Hawaii were for the first time successfully warned in advance.&quot; The word &lt;em&gt;predict&lt;/em&gt; here is somewhat ambiguous. the scientists didn't know the earthquake would happen, but recognized that the earthquake would likely cause a tsunami. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looking at the map below. Where tectonic plates connect, or where there are underwater volcanoes are prime locations to generate tsunamis. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/P7YVV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/P7YVV.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4685" LastEditorUserId="4685" LastEditDate="2016-01-02T17:52:35.973" LastActivityDate="2016-01-02T17:52:35.973" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="7162" PostTypeId="1" AcceptedAnswerId="7164" CreationDate="2016-01-03T14:27:12.980" Score="3" ViewCount="1023" Body="&lt;p&gt;I made a video about what I learnt in my A Level Geology course so far, about igneous rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing I mentioned was that flow banding is mostly only found in silicic rocks (and so mostly rhyolite) because that's what the textbook says.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, someone commented that this may not be true, so I'm curious - what rocks can / does flow banding occur in? &lt;/p&gt;&#xA;" OwnerUserId="3109" LastEditorUserId="725" LastEditDate="2016-01-03T23:39:09.723" LastActivityDate="2016-01-04T10:55:48.723" Title="Does flow banding only occur in silicic rocks?" Tags="|geology|volcanology|rocks|petrology|structural-geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7163" PostTypeId="1" CreationDate="2016-01-03T16:27:57.033" Score="4" ViewCount="232" Body="&lt;p&gt;I am calculating Heating Degree Days and Cooling Degree Days for European Nordic countries (Norway, Sweden, Finland, Denmark, Estonia, Latvia and Lithuania). &#xA;On a paper (Benestad 2008) I read that the base temperature is bounded between 18°C and 22°C, but this value is too much generic for my purposes, as I have to compute exact HDD and CDD for the aforementioned countries.&#xA;Where can I retrieve Base Temperature values for Nordic countries? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;UPDATE:&#xA;I found that EUROSTAT use a value of 15°C as base temperature for computing HDD and CDD. Would it be acceptable?&lt;/p&gt;&#xA;" OwnerUserId="5083" LastEditorUserId="5083" LastEditDate="2016-01-08T17:41:56.650" LastActivityDate="2016-01-08T17:41:56.650" Title="Base temperature value for European Nordic Countries" Tags="|temperature|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="7164" PostTypeId="2" ParentId="7162" CreationDate="2016-01-03T23:38:28.303" Score="4" Body="&lt;p&gt;Flow banding can occur in all igneous rocks, regardless of their composition. Any kind of molten rock that flows may eventually cause some flow banding. Sometimes the flow banding is not even obvious to the eye and can only be detected using geophysical methods such as magnetic anisotropy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's an example of flow banding in a mafic rocks from Skaergaard intrusion in Greenland:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Je2se.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Je2se.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;a href=&quot;http://www.platinaresources.com.au/projects/skaergaard/&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;source&quot;&gt;source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This looks like a sedimentary rock, but it's in fact igneous. Those are layers of minerals such as olivine, pyroxene and plagioclase that settled from a melted magma chamber.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It doesn't even have to be a silicate rock, here's a picture of natrocarbonatite lava from Ol Doinyo Lengai volcano in Tanzania:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TkD3g.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TkD3g.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;a href=&quot;http://ngm.nationalgeographic.com/ngm/0301/feature2/zoom1.html&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;source&quot;&gt;source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously, this rock exhibits flow banding and it hardly has any silica in it.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2016-01-04T10:55:48.723" LastActivityDate="2016-01-04T10:55:48.723" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7165" PostTypeId="1" AcceptedAnswerId="7168" CreationDate="2016-01-04T00:18:50.077" Score="13" ViewCount="7700" Body="&lt;p&gt;I have a basic understanding of what baroclinic and barotropic mean but cannot seem to get my head around baroclinic waves and barotropic waves.&lt;/p&gt;&#xA;" OwnerUserId="5084" LastEditorUserId="111" LastEditDate="2016-01-04T01:21:57.710" LastActivityDate="2017-10-25T15:43:59.853" Title="What are baroclinic and barotropic waves?" Tags="|atmosphere|ocean|oceanography|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7166" PostTypeId="1" AcceptedAnswerId="7185" CreationDate="2016-01-04T05:40:54.047" Score="3" ViewCount="1089" Body="&lt;p&gt;Please help me roughly estimate the magnitude of a quake at a distance d (for example 300km) from the epicenter if the magnitude at the epicenter is m (7 at richter scale) is known.&lt;/p&gt;&#xA;" OwnerUserId="5086" LastActivityDate="2016-01-07T01:05:52.970" Title="How to find the magnitude of earthquakes roughly if we know the Richter scale magnitude of epicenter?" Tags="|geology|earthquakes|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7167" PostTypeId="1" CreationDate="2016-01-04T08:22:42.070" Score="0" ViewCount="390" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xAEwO.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xAEwO.jpg&quot; alt=&quot;Image 2&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KrARB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KrARB.jpg&quot; alt=&quot;Image 1&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the first image the penumbra shadow area is rather small and would match the time length of a lunar eclipse, However, the light source/Sun is far too distant to match the Sun in scale to the Earth in the present solar system model. The second image has the light source/Sun scaled more to the solar system model but the penumbra shadow is much to wide.&lt;/p&gt;&#xA;" OwnerUserId="4617" LastEditorUserId="2570" LastEditDate="2016-05-23T23:33:33.323" LastActivityDate="2016-05-24T05:35:18.883" Title="What model best describes the alignment of the Sun and Moon during a lunar eclipse?" Tags="|moon|sun|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7168" PostTypeId="2" ParentId="7165" CreationDate="2016-01-04T10:03:47.773" Score="7" Body="&lt;p&gt;Barotropic flows are those for which the fluid density $\rho$ depends on pressure $p$ only, i.e. $\rho = \rho(p)$. For example, constant density, isothermal, and isentropic flows are barotropic. Baroclinic flows are flows that are not barotropic. In this case the fluid density depends on pressure AND temperature, salinity, constituent concentration. Heavy fluid sitting adjacent to lighter fluid will sink and rise, respectively. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;These flows are said to be baroclinic, meaning pressure breaking.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Consider the two fluid elements below. In the barotropic case, lines of constant $p$ are parallel to lines of constant $\rho$  so there is no mechanism to generate vorticity. On the other hand, in the baroclinic case, the lines of constant $p$ and $\rho$ are not parallel. The latter arrangement give rise to changes in vorticity $\vec{\omega}$ and circulation because the net pressure force no longer passes through the center of mass of the fluid element.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oYuwa.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oYuwa.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seen another way, take a look at the vorticity equation with density variation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\frac{D\vec{\omega}}{Dt} = (\vec{\omega}\cdot \nabla)\vec{u} + \frac{1}{\rho^2}(\nabla \rho \times \nabla p)$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cross term on the right hand side is the baroclinic torque. When it is zero the flow is barotropic whereas if it is nonzero the flow is baroclinic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When applied to waves in the Ocean the result is that barotropic relates to waves propagating at the ocean surface. Baroclinic relates to waves propagating along density surfaces in the interior of the ocean (or internal waves).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One good example is the surface tide and the internal tide. As the surface tide (regular tide) sweeps around the main oceanic basins, it rubs against the ocean floor giving rise to internal tides. The former are called barotropic tides, whereas the latter are called baroclinic tides.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;P. Kundu, Fluid Mechanics&lt;/p&gt;&#xA;&#xA;&lt;p&gt;B. Sutherland, Internal Gravity waves&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2016-01-20T21:42:48.077" LastActivityDate="2016-01-20T21:42:48.077" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="7169" PostTypeId="1" CreationDate="2016-01-04T18:44:45.820" Score="2" ViewCount="77" Body="&lt;p&gt;Could anyone give me any examples of attempts to predict earthquakes AND tropical storms that have caused more harm then good (e.g: because an area was predicted to have low levels of risk and therefore people were not prepared / the pathway of tropical storm predicted was inaccurate).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am aware that predictions are far from being 100%.&lt;/p&gt;&#xA;" OwnerUserId="5090" LastActivityDate="2016-01-05T23:17:57.647" Title="Hazard event predictions. Examples of predictions causing more harm than good" Tags="|earthquakes|tropical-cyclone|predictability|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7170" PostTypeId="1" CreationDate="2016-01-04T22:06:59.987" Score="5" ViewCount="903" Body="&lt;p&gt;I know that some earthquakes are caused by volcanoes and that some earthquakes can trigger volcanic eruptions close to where the earthquake is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But what if a great earthquake(8.0 or above) occurs and causes there to be a fault line? If more earthquakes of any magnitude occur in the same area the fault line would get deeper and deeper until the mantle is exposed. Then the pressure in the mantle is released and lava starts flowing out of the fault line. Over years this would form a ridge whether that is underwater or inland. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But are any volcanoes actually formed from earthquakes?&lt;/p&gt;&#xA;" OwnerUserId="1388" LastEditorUserId="725" LastEditDate="2016-01-05T01:50:53.517" LastActivityDate="2016-01-05T08:07:21.430" Title="Are volcanoes formed from earthquakes?" Tags="|geology|volcanology|seismology|earthquakes|plate-tectonics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7171" PostTypeId="2" ParentId="6833" CreationDate="2016-01-05T00:02:52.470" Score="4" Body="&lt;p&gt;Inclination is given by&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$I=\arctan(2\cot\theta)$$&#xA;where theta is equal to 90° minus the observer's latitude (in the Northern Hemisphere), therefore&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$I=\arctan(2\cot(90-40))=59,21^\circ$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get declination the following figure helps:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/F119x.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/F119x.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Declination is the angle between geographic north and magnetic north. (I suppose 80°N, 72°W are the coordinates of the North Geomagnetic Pole.) Let's do the math!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$D=\arctan\left({{{33}\over{40}}}\right)=39,52^\circ $$&lt;/p&gt;&#xA;" OwnerUserId="5091" LastEditorUserId="5091" LastEditDate="2016-01-05T22:38:37.920" LastActivityDate="2016-01-05T22:38:37.920" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7172" PostTypeId="1" CreationDate="2016-01-05T00:36:31.950" Score="8" ViewCount="1095" Body="&lt;p&gt;I have just begun reading some notes about modelling and can't seem to understand what a 1°x1° grid or a 2.5° grid or 1/4° grid is. I know it is something related to the resolution of the area over which the model is run. But when a line goes like this, 'the values are archived on 2.5° grid', what exactly should I make of it?&lt;/p&gt;&#xA;" OwnerUserId="5084" LastEditorUserId="192" LastEditDate="2016-01-05T19:29:24.147" LastActivityDate="2016-01-05T19:29:24.147" Title="What exactly is a model grid?" Tags="|models|atmosphere-modelling|climate-models|numerical-modelling|ocean-models|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7173" PostTypeId="2" ParentId="7170" CreationDate="2016-01-05T01:50:26.067" Score="8" Body="&lt;p&gt;From what you wrote, you are assuming several things:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The mantle is made up of molten rock,&lt;/li&gt;&#xA;&lt;li&gt;Faults can go deep enough to reach the mantle.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Both are not exactly accurate.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;lava starts flowing out&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The mantle of the Earth is mostly solid. It has areas where it's partially molten, and that's where the lava in some volcanic eruptions comes from. But mostly, it's solid. Even if you did get a fault line deep down there, it would not release any lava because it's not there to begin with.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...fault line would get deeper and deeper...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Faults can not go too deep. As you go deeper in the earth, rocks stop being brittle and become ductile. They don't break, the flow. Think of chocolate - if you take out chocolate from the freezer you can shatter it to pieces. If you put it in the sun, it bends instead of breaking. Same thing with rocks.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I know that some earthquakes are caused by volcanoes&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The movement of molten rock (magma) underground is the cause of volcanos and earthquakes associated with volcanos. Note that these kinds of earthquakes are usually very weak and their destructive power is very small, at least compared to the actual volcanic eruption.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;some earthquakes can trigger volcanic eruptions&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not really - only if it's a big earthquake you had molten rock around. Which brings me to the next point...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Having said that - actually most of the volcanic eruptions on Earth in fault lines where decompression of mantle occurs. These are the mid ocean ridges that look like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sxBzj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sxBzj.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;sup&gt;Source: Pearson Prentice Hall (?)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And are located here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YZCpv.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YZCpv.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;sup&gt;Source: USGS&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case of mid ocean ridges, you basically have mantle rock melting because of decompression, and this is occurring at fault lines with earthquakes. However, the location where all of this is known and it's all pretty expected. It's also in mid ocean ridges (except Iceland) so the danger to us humans is negligible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other than those cases, the chances of having a surprise magnitude 8 earthquake with a volcano erupting after it are very low.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2016-01-05T08:07:21.430" LastActivityDate="2016-01-05T08:07:21.430" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7174" PostTypeId="2" ParentId="7172" CreationDate="2016-01-05T04:17:36.413" Score="5" Body="&lt;p&gt;Specifically the term &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the values are archived on 2.5° grid&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;means that the values that are being reported are being saved and are available at that resolution for historical values. The higher resolutions (1°x1°, 1/4°x1/4°) mean exactly what they say: the values are reported on a 2-dimensional grid every degree, or quarter degree, across the area of interest.&lt;/p&gt;&#xA;" OwnerUserId="496" LastActivityDate="2016-01-05T04:17:36.413" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7175" PostTypeId="2" ParentId="7172" CreationDate="2016-01-05T08:05:19.137" Score="11" Body="&lt;p&gt;A model is a simplified representation of a system.&lt;/p&gt;&#xA;&lt;p&gt;Rather than try to model everything down to the microscopic level, or as vectors, we often aggregate phenomena across geographic areas, to simplify the computation a lot, and to lose only a little accuracy and precision.&lt;/p&gt;&#xA;&lt;p&gt;So if I want to model the UK, which roughly spans 8°W - 2°E, 50°N - 60°N, that's an area of 10° x 10°. I can split that up into 400 cells, each 0.5°x0.5°. So, starting in the south-west corner, I model the area 8°W-7.5°W x 50°N-50.5°N as a single homogenous area, with no variation within it. And the same for the other 399 cells (8°W-7.5°W x 50.5°N-51°N and so on all the way through to 1.5°E-2°E x 59.5°N-60°N). That would be a 0.5° grid.&lt;/p&gt;&#xA;&lt;p&gt;Note that the gridcells do not overlap at all, and they completely cover the area of interest. (in mathematical terms, they are exclusive and exhaustive - every point of interest is in exactly one gridcell).&lt;/p&gt;&#xA;&lt;p&gt;That can create vast amounts of data - particularly if I'm doing this for the whole world, at second-by-second resolution for ten years, for a few hundred variables of interest. And no one will ever need that amount of precision from my results. So I aggregate up to a more coarse grid: so that I take 25 grid squares that form a larger square, and aggregate each of my statistics of interest in them. So now my area 8°W-7.5°W x 50°N-50.5°N is just one of 25 cells in a square in the coarser grid which spans 8°W-5.5°W x 50°N-52.5°N, and I report statistics for 16 cells in a 2.5° grid, rather than 400 cells in a 0.5° grid.&lt;/p&gt;&#xA;&lt;p&gt;Exactly how that aggregation is done, will vary for each statistic:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;If it's a minimum overnight temperature, then I'll take the minimum across all 25 0.5° gridcells, to give the minimum overnight temperature for the 2.5° grid cell that consists of those 25.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;If it's an average rainfall, I'll take an average.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;If it's insolation per unit area, and I'm interested in insolation per unit land area, then I'll take a weighted average of insolation, weighting by the proportion of each 0.5° gridcell that contains land.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;And then I'll have modelled on a 0.5° grid, and archived on a 2.5° grid&lt;/p&gt;&#xA;&lt;p&gt;Here, for illustration, is Britain in a 100km grid:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9Ujua.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9Ujua.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt; &lt;sub&gt;&lt;a href=&quot;http://www.colorado.edu/geography/gcraft/notes/coordsys/coordsys.html&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;If I wanted to aggregate that to a 200km grid, then the four squares in the bottom-left corner, SQ, SR, SV, SW, would be combined into a single grid cell. And SS, ST, SX, SY would be combined into another grid cell. And so on.&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-01-05T08:12:16.243" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7176" PostTypeId="2" ParentId="7172" CreationDate="2016-01-05T08:36:09.380" Score="5" Body="&lt;p&gt;To add a bit more mathematical conception to the idea of a grid: think about a 2-D grid(X,Y) as a matrix: this matrix represents a solution to the system of equations you are trying to solve at grid point x,y (individual points on X,Y respectively). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is it important to make this distinction? Because knowing the resolution, span, regularity and structure of your grid will determine how you set up your numerical process in order to get reliable numerical solutions. In particular, the boundary conditions are especially sensitive to the grid, which can be difficult to properly place depending on the type of numerical process you are using. Furthermore, in heavy numerical tasks, your grid can often determine how long it takes for your model to resolve (if it even can)!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So yes, a grid is how spatial data is organized and represented, but more importantly, it is fundamentally where the solutions are calculated and live. A well resolved, thought out, and executed grid is fundamental to any scientific study using numerical methods in their argument. &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2016-01-05T08:36:09.380" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7178" PostTypeId="1" CreationDate="2016-01-05T20:04:53.143" Score="5" ViewCount="1020" Body="&lt;p&gt;Question:  Are there any widely accepted published values (or ranges) that classifies a rock as having “low” “medium” “high” -&lt;a href=&quot;https://en.wikipedia.org/wiki/Compressive_strength&quot; rel=&quot;noreferrer&quot;&gt;strength&lt;/a&gt;, -&lt;a href=&quot;https://en.wikipedia.org/wiki/Hardness&quot; rel=&quot;noreferrer&quot;&gt;hardness&lt;/a&gt;, -toughness, and -&lt;a href=&quot;https://en.wikipedia.org/wiki/Cementation_(geology)&quot; rel=&quot;noreferrer&quot;&gt;consolidation&lt;/a&gt; (cementation or &lt;a href=&quot;https://en.wikipedia.org/wiki/Cohesion_(geology)&quot; rel=&quot;noreferrer&quot;&gt;cohesion&lt;/a&gt;?)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UCS Background Material&lt;/strong&gt;:  I have come across some papers that have defined what is considered to be “low”, “medium”, “high” strength rocks as characterized by unconfined (uniaxial) compressive strength (UCS).  This is what I have found:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;“Due to the unique properties of these quartz arenite sandstone reservoirs &lt;em&gt;high&lt;/em&gt; compressive strengths up to 25,000 psi are common,…” (emphasis is mine) (1)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;“In order to define the effect of formation compressive strength on perforator penetration and hole character, various formations in the &lt;em&gt;low-, medium-, and high- strength&lt;/em&gt; ranges were acquired for laboratory shot tests.” (emphasis is mine)  (2).  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The author then lists the rocks tested: &#xA;low ~ 2000 psi UCS ( Austin chalk),&#xA;medium ~ 5000 to 7000 psi UCS (Idiana limestone and Berea sandstone),&#xA;High ~ 11,000+ psi UCS (Carthage limestone)&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;“&lt;em&gt;Ultrahigh-strength&lt;/em&gt; formations….Oman formations in which UCS varies from 20,000 to 55,000 psi.” (emphasis is mine)  (3)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Hardness Background Material&lt;/strong&gt;:  I have seen a paper that has defined the inter-relationship between hardness (using the Brinell hardness number (BHN)) and consolidation, reference 4.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Loosely consolidated material (BHN 2-4 kg/mm2)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Friable-to-consolidated material (BHN 10-15 kg/mm2)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Consolidation Background Material&lt;/strong&gt;:  Reference 5 defines what is “unconsolidated” (damp sand), “weakly consolidated” (Saltwash south), and “strongly consolidated” Castlegate, Berea, etc., qualitatively.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;“unconsolidated” = essentially no cohesion e.g. cohesive forces due to friction, granular interlocking and capillary forces.&lt;/li&gt;&#xA;&lt;li&gt;“weakly consolidated” = can be failed by forces one can generate with their fingers&lt;/li&gt;&#xA;&lt;li&gt;“strongly consolidated” = requires a tool such as an hammer to fail the rock&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Blosser, W. R. (1995, January 1). An Assessment of Perforating Performance for High Compressive Strength Non-Homogeneous Sandstones. Society of Petroleum Engineers. doi:10.2118/30082-MS&lt;/li&gt;&#xA;&lt;li&gt;Thompson, G. D. (1962, January 1). Effects of Formation Compressive Strength on Perforator Performance. American Petroleum Institute.&lt;/li&gt;&#xA;&lt;li&gt;Mustafa, H. D., Briner, A. P., Jumaat, M. S., Grove, B. M., Atwood, D. C., &amp;amp; Judd, T. C. (2012, January 1). Ultrastrong Formations: Perforating Challenges, Limits, and Optimization. Society of Petroleum Engineers. doi:10.2118/159771-MS&lt;/li&gt;&#xA;&lt;li&gt;Vriezen, P. B., Spijker, A., &amp;amp; van der Vlis, A. C. (1975, January 1). Erosion of Perforation Tunnels in Gas Wells. Society of Petroleum Engineers. doi:10.2118/5661-MS&lt;/li&gt;&#xA;&lt;li&gt;Walton, I. C., Chang, F. F., &amp;amp; Lopez de Cardenas, J. (2004, January 1). Perforation Morphology and the Onset of Sand Production. Society of Petroleum Engineers. doi:10.2118/90123-MS&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="538" LastEditorUserId="538" LastEditDate="2016-01-06T14:31:41.970" LastActivityDate="2018-10-12T22:07:10.067" Title="Definitive values that classifies a rock as having “low”, “medium”, and “high” -strength, -hardness, -toughness, and -consolidation?" Tags="|geology|rocks|" AnswerCount="0" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7181" PostTypeId="2" ParentId="7169" CreationDate="2016-01-05T23:17:57.647" Score="2" Body="&lt;p&gt;One example that you may be able to research is the configuration of the tailings storage at the Ranger Uranium Mine in Australia's Northern Territory. The choices they had were either to dig a pit for the tailings, or build a dam for the tailings. A pit would leak a certain amount of contaminants into the surrounding waterways in the Kakadu National Park, and be more susceptible to flooding, but be more resistant to a catastrophic event such as a tropical cyclone, as there is no wall for the high winds to destroy. A tailings dam would be resistant to flooding, and as the construction of a dam can include control over the materials used to line and seal the dam, it would also not continually release contaminants into the environment. However, the dam wall would be susceptible to catastrophic failure in the event of a tropical cyclone, releasing the entire contents of the tailings storage into the environment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This situation highlights the &lt;a href=&quot;https://en.wikipedia.org/wiki/Wicked_problem&quot; rel=&quot;nofollow&quot;&gt;wicked problem&lt;/a&gt; nature of environmental risk assessment. The choice was made in the end to build a dam, and the result of that choice could, at some point in time in the future, result in the escape of millions of tons of toxic and radioactive contaminants into an extremely sensitive waterway. &lt;/p&gt;&#xA;" OwnerUserId="496" LastActivityDate="2016-01-05T23:17:57.647" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7184" PostTypeId="1" AcceptedAnswerId="7191" CreationDate="2016-01-07T00:05:17.953" Score="5" ViewCount="103" Body="&lt;p&gt;&quot;Introduction to Physical Oceanography, 2nd edition&quot; by John Knauss is a popular oceanography textbook. I bought a copy. It ends at page 308, apparently in the middle of the index. (It seems unlikely that the index would end at &quot;tidal,&quot; without having entries for such oceanography favorites as &quot;water, &quot;wind,&quot; and &quot;waves.&quot;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I sent an inquiry to the publisher. The publisher was not helpful. I sent the book back to the vendor, and requested a replacement. The replacement was identical.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone have a copy of the book with index pages beyond 308? Or are they all like that?&lt;/p&gt;&#xA;" OwnerUserId="5106" LastActivityDate="2016-01-07T16:20:52.087" Title="Missing pages in Knauss' &quot;Introduction to Physical Oceanography, 2nd edition&quot;?" Tags="|oceanography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7185" PostTypeId="2" ParentId="7166" CreationDate="2016-01-07T00:57:48.140" Score="3" Body="&lt;p&gt;Your question cannot be answered with any accuracy because the result depends mainly on a key unknown parameter: hypocentral depth D.&lt;br&gt;&#xA;To show this, let me use the empirical relationship known as the Lillie formula:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$m = \log(A) - 2.48 + 2.76*log(d)$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$m$ is the local magnitude (no units).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$A$ is the amplitude of the maximum ground displacement (in micrometers) of the P-wave, measured at 0.8 Hz.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$d$ is your epicentral distance in km for large distances (hundreds of km). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that for low values (when approaching the epicenter) the equation does not hold because the log tends to -inf. That's why these empirical formulas are only used  for long epicentral distances, not at local scale (and definitely not at the epicenter).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Following your example, if your earthquake is very shallow you would have a huge magnitude difference between your station at distance d and the epicenter, whereas if the hypocenter is 600 km deep, m will be very similar in both places. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So you need to know the depth of the earthquake to derive the magnitude in the epicenter. &lt;/p&gt;&#xA;" OwnerUserId="1379" LastEditorUserId="20" LastEditDate="2016-01-07T01:05:52.970" LastActivityDate="2016-01-07T01:05:52.970" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7187" PostTypeId="1" AcceptedAnswerId="7188" CreationDate="2016-01-07T06:32:39.710" Score="11" ViewCount="674" Body="&lt;p&gt;As we know, earthquakes can be induced by human activities. Can we induce earthquakes around faults regularly so that the energy releases regularly, and hence prevent high magnitude earthquakes by stopping large amount of energy releases at one time?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="725" LastEditDate="2016-01-07T09:32:12.803" LastActivityDate="2016-01-10T12:21:20.247" Title="Is it possible to prevent high magnitude earthquakes by induced earthquakes?" Tags="|seismology|earthquakes|human-influence|seismic-hazards|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7188" PostTypeId="2" ParentId="7187" CreationDate="2016-01-07T07:26:05.060" Score="7" Body="&lt;p&gt;The idea of trying to limit energy released by earthquakes and the damage that may result via the use of controlled smaller blast induced quakes is an interesting idea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the problems with this is that we don't know enough about the snags along faults that cause stresses to accumulate during the normal movements along a fault. We also don't know enough about fault surfaces (shapes, undulations and friction factors) of individual fault surfaces. The other thing we don't know is where the snags are located on fault surfaces: along and down the fault surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The strength of snags is one factor which determines how much energy accumulates and is eventually released suddenly when the snag fails.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other factor is the type of movement at the fault zone. Do the fault surfaces slide past one another laterally, does one sub-duct beneath the other, or are they spreading apart.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With some faults, wedge failures may produce large blocks that act a snags. Other snags can be very hard, strong protrusions of rock firmly cemented in the fault surface. Corrugations can also act as snags.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another possible mechanism by which quakes can happen, particularly in the subduction zone is that part of the fault surface that is riding over a subduction zone might hang with no support, due to undulations or point support. If the overhanging rock is not strong enough it can fail and drop. The impact of the dropping block then causes an earthquake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ways in which earthquakes occur are varied and sometimes complex.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="5110" LastEditDate="2016-01-07T19:41:07.990" LastActivityDate="2016-01-07T19:41:07.990" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7189" PostTypeId="2" ParentId="2393" CreationDate="2016-01-07T14:23:28.743" Score="0" Body="&lt;p&gt;I must agree some countries seem to have more gold than others. Using Australia as an example; There is more east coast gold finds, yet the west coast has produced more gold. The east coast states are more populated, so it would make sense more gold deposits where found.&#xA;I read theories that gold was formed from stars going nova after the big bang. Prior to Earth's final formation these now ancient meteors/asteroids deposited gold all over the world. Gold would be found closet to the Earth's core. As gold is a heavy element and Earth's early stages, naturally more gold would be found closer to the core. Confused as Uranium is also heavy but only found in the Earth's crust. Once again I looked to Australia for answers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Australia recorded only 180 impacts, compared to other countries recording over 900. Both Western and Northern Australia record three times more impacts than the East coast. The west coast produced veins of gold while the east coast produced huge nuggets and flecks. The east coast of Australia suffered volcanic eruptions. While the western and northern have few if any inactive volcano's. The vast plans would explain the veins, spread of impact over distances. All confirming the theory but not why uranium is found in the crust in these areas. Perhaps uranium was formed over time from impact of these asteroids or took longer to cook than gold during the big bang. Its odd though that uranium is proficient in the same areas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm just a backyard scrub but for my two bob answer to your question, I'd say gold is more evident on larger continents that are more accessible. Remember Australia is wide as the USA with fewer mountain ranges and a tenth of the population.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the 1900 a man near death and surely out of his mind returned to town claiming to of found a reef of gold a mile long.  Harold Bell Lasseter had rode west to find his fortune, on finding it he lost his way home and the location of his fortune. For 30yrs Lasseter insisted on continuing the trek looking for his goldern mile, until eventually he died of malnutrition and exhaustion. Kalgoorlie in Western Australia was dicovered soon after. Kalgoorlie mines produce 850,000 ounces (28 tonnes) of gold per year.&#xA;Lasseter reef has never been found.&lt;/p&gt;&#xA;" OwnerUserId="5112" LastActivityDate="2016-01-07T14:23:28.743" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7190" PostTypeId="1" CreationDate="2016-01-07T15:03:27.773" Score="8" ViewCount="134" Body="&lt;p&gt;I'm currently living in Oklahoma, and there has been an abnormal amount of earthquakes lately, by abnormal I mean more then 5 in a day(&lt;em&gt;not sure if that's normal or not&lt;/em&gt;)..&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've also been told that in OK earthquakes are a relatively &lt;em&gt;new&lt;/em&gt; thing, now they've brought a bunch of experts in to try to figure out the problem but my question being what could possibly cause so many earthquakes to start happening randomly?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have a couple theories:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Oil wells, we're sucking up all the oil in the ground and the planet is trying to cope with it&lt;/li&gt;&#xA;&lt;li&gt;Underwater waste pipes, idk if these would have anything to do with it, but putting something underground that isn't natural seems like a bad idea to me..&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;For some insight on what's happening see &lt;a href=&quot;http://www.koco.com/news/experts-work-to-determine-whats-causing-all-the-earthquakes/37299816&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt; see also &lt;a href=&quot;http://earthquaketrack.com/p/united-states/oklahoma/recent&quot; rel=&quot;nofollow&quot;&gt;graph&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There has been 30 earthquakes in the past 21 hours.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;&lt;pre&gt;&lt;code&gt;30 earthquakes today&#xA;76 earthquakes in the past 7 days&#xA;196 earthquakes in the past month&#xA;2,213 earthquakes in the past year&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Taken from &lt;a href=&quot;http://earthquaketrack.com/p/united-states/oklahoma/recent&quot; rel=&quot;nofollow&quot;&gt;Today's Earthquakes&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE 2:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;&lt;pre&gt;&lt;code&gt;14 earthquakes today&#xA;81 earthquakes in the past 7 days&#xA;206 earthquakes in the past month&#xA;2,222 earthquakes in the past year&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;September 2016 update&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.usgs.gov/news/magnitudes-oklahoma-earthquakes-shift-upward%22Magnitudes%20for%20Oklahoma%20Earthquakes%20Shift%20Upward%22&quot; rel=&quot;nofollow&quot;&gt;https://www.usgs.gov/news/magnitudes-oklahoma-earthquakes-shift-upward&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does this new development change any of the existing answers?&lt;/p&gt;&#xA;" OwnerUserId="5089" LastEditorUserId="725" LastEditDate="2016-09-10T09:08:40.330" LastActivityDate="2016-09-10T09:08:40.330" Title="Earthquakes in Oklahoma influenced by Humans?" Tags="|seismology|earthquakes|human-influence|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="7191" PostTypeId="2" ParentId="7184" CreationDate="2016-01-07T16:20:52.087" Score="6" Body="&lt;p&gt;I own the Second edition, 2005 reissue of this textbook, purchased through Amazon in August 2009. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;After p308, my copy has only one more page of content (p309), which is the last page of the Index. You indeed have a faulty copy. I recommend you send it back for replacement again and request them to inspect the copy before shipping.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are still unlucky with the second replacement, I would try e-mailing the publisher with your purchase invoice and request a pdf of the book which would complement your hardcopy with the missing page.&lt;/p&gt;&#xA;" OwnerUserId="192" LastActivityDate="2016-01-07T16:20:52.087" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7192" PostTypeId="2" ParentId="7190" CreationDate="2016-01-07T19:02:42.570" Score="5" Body="&lt;p&gt;Short answer is that no this is not normal, which is why there are experts descending on the area to study the situation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your first theory is not likely to be an issue, as oil is produced from a well, the fluids from the surrounding area move into the now available space which leaves the subsurface in a situation that isn't terribly dissimilar to what had been. The oil is produced from tiny spaces in a rock supported matrix and fluid remains present after production, this has some effect but not typically significant, either water will intrude to fill the space, or the reduced pressure will allow gas to expand and fill the space, but the rock matrix provides the support. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Injection of fluids can have a significant effect though, the point of pressure from the injection changes the dynamics of the rocks that are taking on the fluid, which must be injected with enough force to overcome the fluid pressure present in the rocks and induce flow through the pore spaces. The injection could be managed so that the pressures used are just slightly above what is necessary to induce flow, but those flow rates would be very low compared to what is desirable for waste disposal, so higher pressure is used, which can trigger seismic events. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hydraulic fracturing takes this even further, using very high pressure and large volumes of fluids to induce new open flow paths in the rocks, and this certainly has some effect, and can trigger seismic events. Imagine that you have two large blocks of rock that want to slide past each other but are holding the tension without moving, and then someone injects a lubricant that reduces the friction between the two, the friction is reduced to the point that motion will occur.&lt;/p&gt;&#xA;" OwnerUserId="5097" LastActivityDate="2016-01-07T19:02:42.570" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7193" PostTypeId="1" AcceptedAnswerId="9442" CreationDate="2016-01-07T21:50:13.827" Score="6" ViewCount="1040" Body="&lt;p&gt;I am looking for a time-series of hourly precipitation for Naples, Italy. I'd like to learn how to find this sort of data for Italy in general, as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ideally this data would cover &lt;strong&gt;a recent year with no gaps greater than a few days&lt;/strong&gt;, and would come as a spreadsheet with time-stamps and &lt;strong&gt;precipitation measurements on the hour&lt;/strong&gt; side-by-side. I'm not picky and will format as needed, but I haven't found anything close to this yet. Also, public-domain/open-data is much preferred (we all like free things right?) but is not a limiting factor in my search.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;h2&gt;Research thus far:&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;I've searched and cannot find a text-based data source as I described. I think the closest source I've got is the following, which does not have observed hourly precip: &lt;a href=&quot;https://weatherspark.com/history/32302/2014/Naples-Campania-Italy&quot; rel=&quot;noreferrer&quot;&gt;https://weatherspark.com/history/32302/2014/Naples-Campania-Italy&lt;/a&gt; On that page it says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Precipitation&lt;/strong&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;This station provides hourly reports of significant weather events at and around the station, but does not report &lt;strong&gt;the quantity&lt;/strong&gt; of precipitation at the station itself. &lt;em&gt;This is common for weather stations located outside of the United States&lt;/em&gt;, and for a small subset of stations in the United States that are located at lesser used and smaller airports. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm familiar with the difficulty of getting hourly precipitation and certain other meteorological variables from most weather stations outside of the U.S. and major international airports. In many cases, locals have been able to help me, often by providing the data themselves (these locals tend to be experts) or sharing the right channel to reach out to in their country's national government or research institutions. I haven't had such success in Italy though, but I only know/have asked a couple of relevant scientists. In part I'm hoping this question will serve as me asking more Earth scientists who work in Italy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've searched the &lt;a href=&quot;https://open-data.europa.eu/en/data&quot; rel=&quot;noreferrer&quot;&gt;European Union Open Data Portal&lt;/a&gt;, which feels like it would be the right place but is not (yet) as far as I have seen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In searching for digital elevation data (which I'll be using with the precip data in this project), &lt;a href=&quot;https://olinuris.library.cornell.edu/content/gis-data-and-maps-europe#it&quot; rel=&quot;noreferrer&quot;&gt;a Cornell page&lt;/a&gt; pointed me to &lt;a href=&quot;http://www.igmi.org/&quot; rel=&quot;noreferrer&quot;&gt;Italy's Military Geographical Institute&lt;/a&gt;. From what I can tell through a Google Translate lens, this site doesn't offer hourly precip data. I don't speak Italian and have only poked around a couple of pages, so I could be missing something.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;I turn to you, ES:SE. Where can I find historic hourly precipitation data for Napoli, Italia?&lt;/p&gt;&#xA;" OwnerUserId="4789" LastEditorUserId="4789" LastEditDate="2016-01-07T22:28:51.180" LastActivityDate="2017-01-11T06:53:08.930" Title="Where can I get historic hourly precipitation data for Italy?" Tags="|meteorology|measurements|precipitation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7194" PostTypeId="2" ParentId="4781" CreationDate="2016-01-07T23:27:35.463" Score="3" Body="&lt;p&gt;As you noted, the (predictions about) impacts of global climate change are region specific. The general reasoning behind predictions for many regions are similar however, as are some noteworthy bottom lines (such as increased exposure to flooding as your question focuses on), so I'll try to summarize those from rich and reliable sources.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.mdsg.umd.edu/topics/coastal-flooding/storm-surges&quot; rel=&quot;nofollow&quot;&gt;The Maryland Sea Grant website states on its Storm Surges page&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;As sea level rises, flooding due to storms will worsen so that homes and buildings already vulnerable to storm surges will sustain more damage. Powerful storms can damage dwellings or flood low-lying areas with high tides and wind-driven waves. Some Maryland neighborhoods could be underwater completely.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;...&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;A special report, Come High Water: Sea Level Rise and Chesapeake Bay, offers a comprehensive look at the causes and consequences of increasing flooding along Maryland’s coasts. This package, produced by Maryland Sea Grant's magazine Chesapeake Quarterly in partnership with Bay Journal, examines the scientific understanding and projections of the rate of sea level rise in the Chesapeake region; effects on people and the environment; and adaptations and policy responses that are under way or under consideration. &lt;a href=&quot;http://www.chesapeakequarterly.net/sealevel/index.php&quot; rel=&quot;nofollow&quot;&gt;An online interactive page&lt;/a&gt; offers videos, photos, and &lt;strong&gt;an interactive map showing flooding that is predicted to occur&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The PDF of &quot;Come High Water: Sea Level Rise and Chesapeake Bay&quot; has more detailed explanations, data, and citations, and is available from that page.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.mdsg.umd.edu/topics/coastal-flooding/rising-sea-level&quot; rel=&quot;nofollow&quot;&gt;On its Rising Sea Level page&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;http://www.mdsg.umd.edu/news/scientists-unveil-new-projections-sea-level-rise-maryland&quot; rel=&quot;nofollow&quot;&gt;Scientists have forecasted&lt;/a&gt; an increase of as much as 2.1 feet in the Chesapeake Bay by 2050. And by the end of this century, that number could be 3.7 feet or higher. Scientists have identified several reasons, which are described in a video produced by Maryland Sea Grant (below):&lt;/p&gt;&#xA;  &#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;As oceans around the world grow hotter, they also expand because of the chemistry of salt water.&lt;/li&gt;&#xA;  &lt;li&gt;Glaciers and ice caps, including the icy regions around Greenland, are melting.&lt;/li&gt;&#xA;  &lt;li&gt;Since the end of the last ice age, the land around Maryland has been naturally sinking a tiny bit each year — a trend that has accelerated over recent decades.&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That article linked to where the above quote says &quot;&lt;a href=&quot;http://www.mdsg.umd.edu/news/scientists-unveil-new-projections-sea-level-rise-maryland&quot; rel=&quot;nofollow&quot;&gt;Scientists have forecasted...&lt;/a&gt;&quot; has a worthwhile introduction to answer your question and provide context to the source:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;State Should Consider Longevity of Structures Built Near Water, Report Says&lt;/strong&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Maryland residents should plan for the state’s coastal waters to rise by 2.1 feet by the year 2050 and by 3.7 feet or more by the century’s end, according to a new analysis by scientific experts prepared for Gov. Martin O’Malley. The panel reviewed recent evidence about sea level rise in Maryland and globally.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Based on your asking about specific studies that quantify these [climate change] effects: if you are interested in more detailed data and prediction methods, you can easily find various climate forecasting models if you search for them. One example is &lt;a href=&quot;http://www.narccap.ucar.edu/&quot; rel=&quot;nofollow&quot;&gt;NARCCAP&lt;/a&gt;. It and many other climate forecasting models are public-domain but fairly technical. Another example is &lt;a href=&quot;https://www.data.gov/climate/coastalflooding/&quot; rel=&quot;nofollow&quot;&gt;https://www.data.gov/climate/coastalflooding/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many climate change impacts are predicted based on environmental models and the data sets they produce. &lt;strong&gt;For a glimpse at modeling efforts very relevant to your question, you could explore these papers:&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://dspace.mit.edu/bitstream/handle/1721.1/53046/48625420-MIT.pdf?sequence=2&quot; rel=&quot;nofollow&quot;&gt;DesAutels, 2000. Upper-Ocean Influences on Hurricane Intensification&#xA;Modeling.&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;&lt;a href=&quot;http://link.springer.com/article/10.1007/s10584-010-9978-3&quot; rel=&quot;nofollow&quot;&gt;Hellegatte et al, 2010. Assessing climate change impacts, sea level rise and storm surge risk in port cities: a case study on Copenhagen.&lt;/a&gt;&lt;/strong&gt; &lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;&lt;a href=&quot;https://ceprofs.tamu.edu/folivera/Papers%20PDFs/2011%20Global%20warming%20and%20hurricanes%20-%20The%20potential%20impact%20ofhurricane%20intensification%20and%20SLR%20on%20coastal%20flooding%20.pdf&quot; rel=&quot;nofollow&quot;&gt;Mousavi et al, 2009. Global warming and hurricanes: the potential impact of hurricane intensification and sea level rise on coastal flooding.&lt;/a&gt;&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://ncar.ucar.edu/press/evaluating-the-effects-of-future-sea-level-rise-and-storm-surges-along-us-coastlines&quot; rel=&quot;nofollow&quot;&gt;NCAR Article: Evaluating the Effects of Future Sea Level Rise and Storm Surges Along U.S. Coastlines&lt;/a&gt; and &lt;a href=&quot;http://iopscience.iop.org/article/10.1088/1748-9326/7/1/014032&quot; rel=&quot;nofollow&quot;&gt;associated paper: Tebaldi et al, 2012. Modeling sea level rise impacts on storm surges along US coasts.&lt;/a&gt; Both of these support and address your question in the first place.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The Hellegatte et al, 2010 paper is focused on economic analysis which you may be interested in: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;For  instance,  the  total  losses  (direct  and  indirect)  caused&#xA;  by  a  present-day  100-year  storm  surge  event,  at  150  cm  above  normal  sea  level,&#xA;  are estimated to reach EUR 3 billion with no protection. In the aftermath of such&#xA;  an event, thousands of jobs would be lost and thousands would be created in the&#xA;  construction  sector.  Other  types  of  impact  have  been  disregarded  here,  but  may&#xA;  also be important (e.g., casualties, illness, psychological trauma, disruption of social&#xA;  networks, loss of national competitive strength and market positions, loss of cultural&#xA;  heritage, city attractiveness, etc.). Even with the relatively narrow set of economic&#xA;  impacts  considered  here,  the  reconstruction  process  would  last  several  years  and&#xA;  cause a significant shock to the local and the national economy.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The Mousavi et al, 2009 paper provides specific predicted sea level rise quantities which may be more what you are after:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;For  the  Corpus  Christi,  Texas,&#xA;  United  States  study  region,  mean  projections  indicate  hurricane  flood  elevation&#xA;  (meteorologically  generated  storm  surge  plus  sea  level  rise)  will,  on  average,  rise&#xA;  by 0.3 m by the 2030s and by 0.8 m by the 2080s. For catastrophic-type hurricane&#xA;  surge events, flood elevations are projected to rise by as much as 0.5 m and 1.8 m by the 2030s and 2080s, respectively.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Again there are many modeling/prediction and analysis efforts and varying scenarios for different regions. If you were more specific about the region and particular analysis you're interested in, folks could probably share more specific answers.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;TL;DR: Sea level is predicted to rise due to climate change, to varying extents place-to-place, and that rise in sea level will increase the magnitude of damage many places are exposed to due to storms, which are also predicted to pose a more significant threat due to increased intensity and frequency.&lt;/p&gt;&#xA;" OwnerUserId="4789" LastEditorUserId="4789" LastEditDate="2016-06-11T03:58:28.293" LastActivityDate="2016-06-11T03:58:28.293" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7195" PostTypeId="2" ParentId="7190" CreationDate="2016-01-08T01:59:23.730" Score="8" Body="&lt;p&gt;The sudden and recent occurrence of multiple earthquakes in Oklahoma is due to a widespread redistribution of stresses within the ground, particularly at depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Installing large pipes underground for storm water, waste water, or potable water or even digging a basement under every house in an entire city will only cause a very minor localized redistribution of ground stresses, near the Earth's surface. Such minor redistributions of stresses will not lead to earthquakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As Blaydes states, injection of fluids and fracking will induce additional stresses and they can also lead to faults and ground fissures becoming lubricated and thus prone to movement, resulting in earthquakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Removal of a liquid from an underground reservoir, oil or water, can have an adverse impact. If the reservoir is naturally pressurized, tapping the reservoir will reduce its pressure and the affect that has on the surrounding rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Depending on the circumstances, releasing pressure can unlock rock, allowing it to move. It's a bit like having a number of blocks of lumber clamped together by a vice a or a clamp. Provide enough stress (clamping force) and everything is held together nicely. Too much stress and the blocks become damaged due to the strength properties of the individual blocks. Not enough stress and the blocks become free to move relative to one another.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is well documented, particularly in the US, that removal of &lt;a href=&quot;http://geochange.er.usgs.gov/sw/impacts/hydrology/vegas_gw/&quot;&gt;water&lt;/a&gt; and &lt;a href=&quot;http://www-radar.jpl.nasa.gov/CrustalDef/oilfields/index.html&quot;&gt;oil&lt;/a&gt; from underground reservoirs can cause surface subsidence. In the case of the Lost Hills and Belridge oil fields in California, subsidence rates of up to 40 mm/day (greater than 400 mm per year) were measured. In the &lt;a href=&quot;http://www.tulane.edu/~sanelson/Natural_Disasters/subsidence.htm&quot;&gt;Wilmington oilfield&lt;/a&gt; at Long Beach, California, an area 50 square kilometres subsided. In the centre of the subsidence area the maximum subsidence was 9 meters. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The removal of liquids from underground reservoirs results in a reduction of fluid pressure which causes the pore spaces to close and the sediments to compact, resulting in subsidence. As the sediments compact the rock above it also subsides. Under certain circumstances, such ground movements can induce earthquakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Oklahoma's situation, oil pumping, fracking and fluid injection into oil wells are very likely candidates for the causes of earthquakes experienced there.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-01-08T01:59:23.730" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7196" PostTypeId="2" ParentId="4248" CreationDate="2016-01-08T03:35:25.347" Score="4" Body="&lt;p&gt;Here's one idea to account for meteorological extremes in our climate models, though I'm not sure if it answers your question and am less certain if it qualifies as reliable (open for feedback on that too):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take a regional climate model which has simulated into the past and the future. We also have a few decades of observed data to compare the same time period of simulated past. The observed data is going to capture the extreme events much better in every way of course. So, in projecting into the future, if we want to maintain those extremes, we can use the change factor (based on averages, e.g. monthly means) from past-simulation==&gt;future-simulation in order to project past-observed==&gt;future-predicted. Those future-predictions will have the extreme events as they came in the past but with the changed magnitude based on the climate model's past versus future simulations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This could be applied to meteorological data such as precipitation and other weather variables in order to inform us about the driving weather forces we'll face in future scenarios. In this way our climate models account for meteorological extremes we've observed recently and in the past, which the models may otherwise fall short on.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Otherwise, as folks have explained in comments on the OP, we simply don't have extensive enough observed data that we can rely upon to calibrate these rarer frequency events. I think your last two bullet points sum up our predicament fairly well:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;The available measurements are from a 100-200 year observation period (at best);&lt;/li&gt;&#xA;  &lt;li&gt;We do not have too much data from different climatic conditions (there might be some phenomena which are not (or not adequately) taken into account in current models, we are somehow biased by the observed, prior 100 year conditions.&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, here are a few studies and leads you could explore which try to overcome these challenges in modeling extreme event return intervals and Probable Maximum Precipitation. These seem like they might be addressing your last question but hopefully it helps clarify the potential out there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This one using &lt;a href=&quot;https://www.google.com/search?q=extreme%20value%20theory%20modeling%20return%20interval&quot; rel=&quot;nofollow&quot;&gt;extreme-value theory&lt;/a&gt;: &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/joc.1155/pdf&quot; rel=&quot;nofollow&quot;&gt;Van Den Brink et al, 2004. Estimating return periods of extreme events from ECMWF seasonal forecast ensembles.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...applications to meteorological and hydrological situations are&#xA;  always  hampered  by  the  brevity  of  the  available  datasets,&#xA;  as  the  required  return  levels  exceed  the  record  lengths  by  a&#xA;  factor of 10 to 100. In order to overcome this problem, we u&#xA;  se archived data from all past seasonal forecast ensemble&#xA;  runs  of  the  European  Centre  for  Medium-Range  Weather  F&#xA;  orecasts  (ECMWF)  since  1987  as  input  for  extreme-value&#xA;  statistics analysis. We make use of the fact that the seasonal forecast has little seasonal skill for the Netherlands, which&#xA;  implies that the ensembles can be regarded as i&#xA;  ndependent sets that cumulate to over 1500 years.&#xA;  We investigate the hydraulic response in the Netherlands&#xA;  to extreme synoptic-scale weather systems by studying the&#xA;  extreme-value  distributions  of  sea  storm  surge  levels,  wa&#xA;  ves  and  river  discharges.  The  application  is  detailed  in  four&#xA;  practical examples originating from coastal protection, ri&#xA;  ver flooding protection, and water management problems. The&#xA;  long record length of the ECMWF data reduces the uncertainty in the 10&#xA;  3&#xA;  -year and the 10&#xA;  4&#xA;  -year return values considerably&#xA;  with respect to the results based on observational time ser&#xA;  ies. The ECMWF dataset gives the opportunity to explore the&#xA;  distribution of events that depend on several kinds of extreme (Van Den Brink et al, 2004).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This one using the growth factor method, or &quot;NERC M5 method&quot;, as explained on page 10: &lt;a href=&quot;http://met.no/filestore/metnoReport13-2011.pdf&quot; rel=&quot;nofollow&quot;&gt;Skaugen and Førland, 2011. Future change in extreme precipitation estimated in Norwegian catchments.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And here is a study which sums the methods up pretty well and proposes a new one for further research, which sounds good to me and relatively like what I described in pretty broad, simple terms in the first part of my answer: &lt;strong&gt;&lt;a href=&quot;http://met.no/filestore/metnoReport_082012.pdf&quot; rel=&quot;nofollow&quot;&gt;Dyrrdal, 2012. Estimation of extreme precipitation in Norway and a summary of the state-of-the-art.&lt;/a&gt;&lt;/strong&gt; There's many quote-worthy passages in this one so I think I'll leave it to you to explore. Sections 3, 4, and 5 are what I imagine you're most interested in because they cover, respectively, the state-of-the-art guidelines/methods from the World Meteorological Organization and various nations; a proposed new-and-improved method; and a conclusion summarize the above. &lt;/p&gt;&#xA;" OwnerUserId="4789" LastEditorUserId="4789" LastEditDate="2016-01-08T16:07:12.820" LastActivityDate="2016-01-08T16:07:12.820" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7198" PostTypeId="5" CreationDate="2016-01-08T15:18:09.347" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2016-01-08T15:18:09.347" LastActivityDate="2016-01-08T15:18:09.347" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7199" PostTypeId="4" CreationDate="2016-01-08T15:18:09.347" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2016-01-08T15:18:09.347" LastActivityDate="2016-01-08T15:18:09.347" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7200" PostTypeId="1" CreationDate="2016-01-08T15:21:01.307" Score="6" ViewCount="444" Body="&lt;p&gt;Is there a simple formulation to estimate the rate of salt precipitation in a brine given its ion concentrations and the evaporation rate? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example: if we know the concentrations of Cl&lt;sup&gt;−&lt;/sup&gt;, Na&lt;sup&gt;+&lt;/sup&gt;, Mg&lt;sup&gt;2+&lt;/sup&gt;, SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2−&lt;/sup&gt;, Ca&lt;sup&gt;2+&lt;/sup&gt;, K&lt;sup&gt;+&lt;/sup&gt; of a sea-water brine at a known temperature &lt;em&gt;T&lt;/em&gt;, what salt(s) and how much of each will precipitate for a given evaporation rate &lt;em&gt;E&lt;/em&gt; (assuming time enough for equilibrium)?&#xA;Can you refer to a concise text-book or article?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I need something that goes beyond the simplistic saturation concentration concept (i.e., prescribed limit for diluted salt concentration). The effects of life in the solution can be dismissed. &lt;/p&gt;&#xA;" OwnerUserId="1379" LastEditorUserId="725" LastEditDate="2016-01-13T04:00:38.163" LastActivityDate="2016-01-15T12:41:13.120" Title="A simple formulation to calculate the sequence and rate of salt precipitation in a brine?" Tags="|oceanography|geochemistry|precipitation|sedimentology|evaporation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7201" PostTypeId="1" CreationDate="2016-01-08T21:19:04.057" Score="4" ViewCount="161" Body="&lt;p&gt;I have some queries regarding grid. What does this mean.&#xA;The grid has spatial resolution of 1/2 degrees latitude × 2/3 degrees longitude.?&lt;/p&gt;&#xA;" OwnerUserId="5122" LastActivityDate="2016-01-08T21:19:04.057" Title="meaning of Grid resolution" Tags="|meteorology|geophysics|geology|earth-observation|" AnswerCount="0" CommentCount="3" ClosedDate="2016-01-09T08:43:04.180" ContentLicense="CC BY-SA 3.0" />
  <row Id="7207" PostTypeId="2" ParentId="7103" CreationDate="2016-01-09T07:17:18.027" Score="2" Body="&lt;p&gt;I think you're overestimating the amount of knowledge you need to really understand it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The short answer is basically exactly what you said: air and water have extremely different heat capacities. &lt;em&gt;How the water itself behaves&lt;/em&gt; is a whole other can of worms, but you don't need to worry about the nuances of ocean circulation (which I've forgotten myself! undergrad was quite a while ago) to understand the basics of how SST and air temperature are different. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are certainly many, many exceptions to the general patterns you mention, but to answer that you have to delve into the intricacies of circulation in the region you're studying. Wind patterns have strong effects on surface circulation (e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Sverdrup_balance&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Sverdrup_balance&lt;/a&gt;), but &lt;a href=&quot;http://science1.nasa.gov/earth-science/oceanography/physical-ocean/salinity/&quot; rel=&quot;nofollow&quot;&gt;Salinity&lt;/a&gt; plays a major factor as well in areas of intense rainfall or ice melting for example. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;TL;DR: you're right. :)&lt;/p&gt;&#xA;" OwnerUserId="5125" LastActivityDate="2016-01-09T07:17:18.027" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7208" PostTypeId="2" ParentId="7153" CreationDate="2016-01-09T07:52:07.623" Score="1" Body="&lt;p&gt;You may be better off getting a more precise answer by cross-posting this physics if you want a precise mathematical explanation of the model. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, axial precession, as mentioned above, is different than axial tilt. Both change over time, but on different time scales. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, the answer is it has most certainly been explored: &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;nofollow&quot;&gt;Milankovitch cycles&lt;/a&gt; are an attempt to explain patterns of solar forcing on climate. The wikipedia article does a fairly good job of laying out the foundation of the theory, which is that there are three key components influencing solar forcing: eccentricity (how elliptical our orbit is), axial tilt (the change in amount of tilt of the earth), and axial precession (the actual change of direction of the poles). All three components operate on different time cycles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately for us, the nice Milankovitch theory leads to a huge conundrum: the predictions don't play out as expected. Physics dictates that eccentricity would have the weakest effect of the three, but the largest fluctuations are seen in roughly 100ky intervals (tilt and precession operate on roughly 25k and 50k intervals, eccentricity roughly 100k). This leads to the &lt;a href=&quot;https://en.wikipedia.org/wiki/100,000-year_problem&quot; rel=&quot;nofollow&quot;&gt;100,000 year problem&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, all of this is in the context of climate on the global scale, but the point applies just as well: nobody has a conclusive answer as to what exactly is going on, hence the entire field of paleoclimate. Unfortunately for scientists, the Earth is far from a simple rock: our physical (ocean, atmosphere) and biological systems are so complex that it is often too simplistic to pin down changes on one particular phenomenon on a geological time scale. People can study the temperatures  of individual sites over time, but determining the big picture cause of those fluctuations is tough enough for the planet as a whole, much less for a location as specific as the Salisbury Plain. &lt;/p&gt;&#xA;" OwnerUserId="5125" LastEditorUserId="5125" LastEditDate="2016-01-09T07:57:23.590" LastActivityDate="2016-01-09T07:57:23.590" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7209" PostTypeId="2" ParentId="7103" CreationDate="2016-01-09T08:58:56.583" Score="3" Body="&lt;p&gt;You're right. Water has a much higher specific heat capacity than air, so will change temperature much more slowly. This means that, &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the sea surface tends not to reach the same extremes as the air (hence the seasonal effect that you mentioned) &lt;/li&gt;&#xA;&lt;li&gt;the sea tends to lag behind the air in seasonal changes &lt;/li&gt;&#xA;&lt;li&gt;the air readily heats and cools with day and night, while the sea does this much less; so which one is warmer can vary on a diurnal as well as a seasonal basis. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;All this can then be greatly complicated by sea and air currents, especially vertical circulation in the ocean - but you have the right idea. &lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2016-01-09T08:58:56.583" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7211" PostTypeId="2" ParentId="7187" CreationDate="2016-01-10T12:21:20.247" Score="2" Body="&lt;p&gt;The main problem with this entire proposal is that of simple &quot;Trust:&quot; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Causing an earthquake is hardly like causing a spring rainstorm! &quot;Human activities&quot; may indeed cause earthquakes, but determining the &quot;Magnitude&quot; of the proposed earthquake in advance is, in all practical senses, an actual &quot;crap-shoot.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further, it's exceedingly difficult to get available &quot;Earthquake Experts&quot; to arrive at any meaningful consensus. For example: How much &quot;push,&quot; at what point along the fault-line, will be sufficient to cause how great a magnitude of earthquake? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Asking a dozen &quot;top&quot; experts will result in as many answers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nor, evidently, is it possible to get anything resembling any sort of &quot;guarantee&quot; as to when a &quot;Natural&quot; (as opposed to our hypothetical &quot;Induced&quot;) earthquake to take place. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's not even anything resembling a consensus of opinion as to when a &quot;Natural&quot; earthquake will happen--- or which &quot;test&quot; is the most accurate? Runaway pets in general? Runaway cats only? The actions of birds? The responses of fish? Subsurface Infra-sonic wave generation within the fault-line? Surface bulging or subsidence? &lt;strong&gt;&lt;em&gt;What?&lt;/em&gt;&lt;/strong&gt; Which is the &quot;more-accurate&quot; way?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is not an activity the public would welcome with smiles and serene gazes; considering the real-world possibilities of &quot;worst-case scenario events&quot; such as the taking-place of &quot;multi-earthquake-propagation(s)&quot; along portions of an entire branching fault-line.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A cloud-seeding experiment that went awry may break vehicle windows, costing the governments (should government agree on compensation) a few tens of thousands of dollars; a goof creating an earthquake in hopes of reducing the severity of some purportedly-pending natural earthquake that had, instead, propagated into a &quot;Scale-Topper&quot; earthquake could have the potential of causing hundreds if not thousands of injuries and/or deaths, with the potential of tens of trillions of dollars in damages. Most governments would be bankrupted if they even considered assuming financial responsibility.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With the almost-unimaginable risk-potential inherent in this, I can't see any &quot;sane&quot; individual being willing to risk his career---and his very life---in a &quot;crap-shoot&quot; that the unknown true potential of the experiment won't get out of control.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Conversely, I am not certain I could honestly trust any person with such a serious and &lt;strong&gt;LITERALLY EARTH-SHAKING RESPONSIBILITY.&lt;/strong&gt; Particularly if he had been (or had only seemed) majorly self-assured with his predictions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nor do I feel that the public as a whole would have confidence in the individual(s).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am frankly very curious who would have both the guts and either monumental arrogance or staggeringly-huge self-confidence to push such an monumental, untried, scientific agenda through, against the increasingly-worried face of what would surely escalate into a monumental confrontation of public-opinion worries and fears versus government-mandated actions.&lt;/p&gt;&#xA;" OwnerUserId="5130" LastActivityDate="2016-01-10T12:21:20.247" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7212" PostTypeId="1" AcceptedAnswerId="7215" CreationDate="2016-01-10T15:29:57.030" Score="50" ViewCount="47893" Body="&lt;p&gt;I am in O'Fallon, Missouri and today it is -15 °C (5 °F) outside. I was taught water freezes at 0 °C (32 °F). I could understand if it was exactly 0 °C (32 °F) that the water might not be turning to ice, but how can it be 15 °C (27 °F) below water's freezing point and still be liquid water? The water is still moving due to the wind, which I think shows it has no plan of freezing. How can this be? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question may be too broad because there may be more than one reason why it isn't freezing, but I don't know of any. I tried to narrow it by giving my exact location and temperatures. It is a pond in my backyard. From what I've seen through Google, it may have something to do with crystallization rate? Thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="5132" LastEditorUserId="725" LastEditDate="2017-03-04T02:05:17.883" LastActivityDate="2022-01-16T00:04:24.200" Title="Why is the pond in my backyard not frozen when it is -15 °C (5 °F) outside?" Tags="|geophysics|temperature|water|ice|thermodynamics|" AnswerCount="14" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7214" PostTypeId="2" ParentId="7212" CreationDate="2016-01-10T17:31:26.657" Score="10" Body="&lt;p&gt;This could be because the air cools and heats faster than water. Air has a lower &lt;a href=&quot;https://en.wikipedia.org/wiki/Heat_capacity#Specific_heat_capacity&quot;&gt;Specific Heat&lt;/a&gt; than water. It may take some time for the water to freeze.&lt;/p&gt;&#xA;" OwnerUserId="5133" LastActivityDate="2016-01-10T17:31:26.657" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7215" PostTypeId="2" ParentId="7212" CreationDate="2016-01-10T18:37:58.760" Score="53" Body="&lt;p&gt;Water melts at 0 °C (32 °F) but freezing is a more complicated affair.  It is  safe to say water gains the ability to freeze at 0 °C, but it can get much cooler before it actually does so resulting in supercooled water.  Water in this state can rapidly solidify when suitable ice nuclei are introduced.  For example, in convective clouds, liquid water can be observed at temperatures as low as -40 °C.  However, the water in your pond isn't supercooled.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You say the air is 5 °F, but what is the temperature of the water (probably above 0 °C)?  Ultimately it is the water that needs to be below freezing for ice formation to occur. How deep is the pond in your backyard? Water, compared to air, has a much better ability to retain heat and the bigger the volume of water, the more of a heat reservoir you have to deal with.  Freezing itself is an exothermic process and ice formation will heat the surrounding water.  The pond is probably not pure water and full of ions (e.g. salts) it has picked up from the ground, which lowers the melting point of water. All of these effects make it more difficult for water in your pond  to actually freeze and could explain what you are seeing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of these effects, the heat capacity of the water and the temperature of the ground underlying the pond are probably the primary contributors. Underneath the pond is the ground and it too is a heat reservoir. Both are probably warmer than the melting point of water even though the air temperature is much colder.  If a fluid is cooled from above, the cool fluid sinks toward the bottom.  If a fluid is warmed from below, the warm fluid rises.  Only one of these needs to be happening to start convection but it is likely that the ground below the pond is warmer than the pond and both the warm ground and cool air will drive convection in the pond.  This, in turn, means your pond is well mixed and you will need to extract enough energy from the system to cool down all of the water and cool the ground below the pond to give ice the chance to form on the surface. This will take time (on the order of days/weeks) of continual sub-freezing air temperatures to accomplish.  You'll have a much easier time freezing your pond than a large lake, but it still won't be an overnight process.&lt;/p&gt;&#xA;" OwnerUserId="64" LastEditorUserId="1087" LastEditDate="2016-01-12T14:01:20.340" LastActivityDate="2016-01-12T14:01:20.340" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="7216" PostTypeId="2" ParentId="7212" CreationDate="2016-01-10T19:07:04.060" Score="15" Body="&lt;p&gt;The water in a pond is in contact with the ground and the ground is not even close to freezing even if the air temperature is 27° below freezing.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2016-01-10T19:07:04.060" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7217" PostTypeId="2" ParentId="7212" CreationDate="2016-01-10T19:14:20.527" Score="57" Body="&lt;p&gt;Water is a rather strange substance. With most substances, the solid phase is denser than is the liquid phase. This is not the case with water. Ice is less dense than liquid water. A side effect of this effect is that liquid water very close the the freezing point is less dense than is slightly warmer water. That very cool water sinks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Liquid fresh water achieves its maximum density at a temperature of 4 °C (40 °F). This means that a pond or lake cannot freeze until the entire body of water is cooled to 4 °C. Only then can the upper surface of the water cool to below 4 °C, and then eventually freeze.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to the water itself needing to be cooled to 4 °C before freezing can commence, the water-saturated ground beneath the pond has to be cooled as well. Until then, that warmer ground will transfer heat to the pond and keep it from freezing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How long it takes before a body of water to first start freezing depends on a number of parameters. These include the size and depth of the body of water, the nature of the ground beneath the body of water, the weather leading up to the cold weather, and windiness. The question doesn't mention the depth of the pond, but it's only been below freezing in O'fallon, Missouri for about 24 hours, and temperatures had been quite balmy before that. That 24 hours span of sub-freezing weather is more than enough time to freeze a small puddle, but certainly not a lake, and probably not even a pond.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question also mentions that it's windy. For a body of water to freeze, it needs a cooler layer of water atop the 4 °C thermocline. Winds act to keep the water well-mixed. &lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2016-01-10T19:14:20.527" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="7219" PostTypeId="2" ParentId="7212" CreationDate="2016-01-10T23:56:18.217" Score="22" Body="&lt;p&gt;Due to &lt;a href=&quot;https://en.wikipedia.org/wiki/Convection&quot; rel=&quot;nofollow noreferrer&quot;&gt;convection&lt;/a&gt; &lt;em&gt;(the cold water sinks while the warm water rises)&lt;/em&gt;, the &lt;em&gt;entire&lt;/em&gt; pond needs to be brought to near-freezing temperatures before the surface can freeze.  With only the top of the pond in contact with the cold air, this takes a long time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;​‌‍​‌‍Additionally, the ground &lt;em&gt;(which is not cooled by convection)&lt;/em&gt; will take even longer to cool down, meaning the ground will warm the bottom of the pond.  That warm water will rise to the top, lengthening the freezing process.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It takes time for things to freeze.  The above conditions cause the pond to freeze slowly, but if the air were to remain below-freezing forever, eventually the entire pond would freeze over &lt;em&gt;(starting with the top layer and working its way down - when the top turns to ice it no longer sinks because &lt;a href=&quot;https://physics.stackexchange.com/questions/78414/why-does-ice-have-a-lower-density-than-water&quot;&gt;ice has lower density than water&lt;/a&gt;)&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is why, if you travel north to Minnesota where ice fishing is common, they'll tell you the weather needs to be &lt;em&gt;(mostly)&lt;/em&gt; below freezing for weeks before the lake is safe to walk/drive on.&lt;/p&gt;&#xA;" OwnerUserId="393" LastEditorUserId="-1" LastEditDate="2017-04-13T12:40:15.470" LastActivityDate="2016-01-11T20:22:29.573" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7222" PostTypeId="1" AcceptedAnswerId="7224" CreationDate="2016-01-11T05:15:05.790" Score="3" ViewCount="803" Body="&lt;p&gt;I am learning about the several modes of radar that are used to study structure of thunder storms and mesoscale systems. There are three modes of radar scans as documented here - &lt;a href=&quot;https://www.wmo.int/pages/prog/www/IMOP/publications/IOM-88_TM-Radars/IOM-88_Module-D.pdf&quot; rel=&quot;nofollow&quot;&gt;Weather Radar Systems&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have only used the Plan Position Indicator(PPI) mode to track thunder storms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could somebody who has used the Range Height Indicator(RHI) mode as a meteorologist or using it as part of their research work put up a sample RHI mode scan for a thunderstorm(can be supercell)  explain the following&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;What extra information can be gleaned from the RHI mode that is not available with the PPI mode ? &lt;/li&gt;&#xA;&lt;li&gt;Can phenomena such as &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Back-sheared_anvil&quot; rel=&quot;nofollow&quot;&gt;back sheared anvil&lt;/a&gt; be observed from the RHI mode ?  Also can anvil rain be inferred from RHI mode?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2016-01-11T08:58:46.143" LastActivityDate="2016-01-11T14:44:28.937" Title="Using Range Height Indicator scan of radar" Tags="|meteorology|thunderstorm|radar|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7223" PostTypeId="2" ParentId="7212" CreationDate="2016-01-11T06:21:10.717" Score="5" Body="&lt;p&gt;In addition to the accepted answer from Casey, it is likely that the sun is warming the pond over the course of a day more than it warms the thermometer used for the temperature readings you are quoting, as thermometers are kept inside a &lt;a href=&quot;https://en.wikipedia.org/wiki/Stevenson_screen&quot; rel=&quot;nofollow&quot;&gt;Stevenson Screen&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="978" LastEditorUserId="978" LastEditDate="2016-01-11T21:24:05.493" LastActivityDate="2016-01-11T21:24:05.493" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7224" PostTypeId="2" ParentId="7222" CreationDate="2016-01-11T14:44:28.937" Score="3" Body="&lt;p&gt;A vertical cross section in RHI mode reveals vertical structure that you can't directly observe in a horizontal PPI scan.  In the image below you can clearly see that there is a significant bounded weak echo region (&lt;a href=&quot;https://en.wikipedia.org/wiki/Bounded_weak_echo_region&quot; rel=&quot;nofollow noreferrer&quot;&gt;BWER&lt;/a&gt;).  You could put this together from PPI scans at different scan elevations combined for a 3D view but with RHI you can see this from a single scan.  You can also get a sense of the anvil structure as shown in the image below.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whether you can determine anvil rain or structure is going to be affected by the particular radar and where it is located.  Each radar band has pros/cons related to detection and attenuation but if you take these into account then you could be able to determine the features you are interested in.  You should also be able to observe Doppler winds in RHI and if you are doing this in the field with research radars it is a good bet you have dual-polarimetric data as well.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a &lt;a href=&quot;http://www.chill.colostate.edu/w/Selected_dual_polarization_observations_in_a_supercell_thunderstorm:_8_June_2012&quot; rel=&quot;nofollow noreferrer&quot;&gt;presentation of RHI scans in supercells&lt;/a&gt; with dual-pol data.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/x75Gy.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/x75Gy.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2016-01-11T14:44:28.937" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7225" PostTypeId="1" CreationDate="2016-01-11T15:00:53.897" Score="6" ViewCount="49" Body="&lt;p&gt;I know that typical values for the Brunt–Väisälä frequency, $N$, are of the order $10^{-2} \mathrm{s}^{-1}$, but what is the strongest observed stability?  And how deep are such strong layers?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am interested in running idealised simulations for such situations.&lt;/p&gt;&#xA;" OwnerUserId="183" LastActivityDate="2016-01-11T15:00:53.897" Title="What is the strongest observed static stability in the troposphere?" Tags="|meteorology|atmosphere|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7227" PostTypeId="1" CreationDate="2016-01-11T16:35:39.403" Score="7" ViewCount="65" Body="&lt;p&gt;Some geochemistry papers that I have read contain crossplots of compositional components that resulted from different analyses of a rock sample.  For example, one is the percent volume of TiO&lt;sub&gt;2&lt;/sub&gt; versus parts per million (ppm) of Nb.  Results from such a plot seem highly suspect to me because of the closed nature of both attributes.  However, I am not a geochemist, so I would appreciate any feedback on the validity of such results from both a geochemical and data analysis perspective.&lt;/p&gt;&#xA;" OwnerUserId="5149" LastEditorUserId="725" LastEditDate="2016-01-13T03:57:09.090" LastActivityDate="2016-02-12T05:10:54.357" Title="Are trends in crossplots of compositional data from different analyses valid?" Tags="|geology|geochemistry|petrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7228" PostTypeId="1" CreationDate="2016-01-11T17:21:32.907" Score="6" ViewCount="473" Body="&lt;p&gt;I'm trying to find how much water would be on the surface of Earth and how much surface would it cover (how much land will remain) if all the ice at the North and South Poles (and everywhere else) would melt. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please provide the source of the information. &lt;/p&gt;&#xA;" OwnerUserId="5151" LastEditorUserId="11908" LastEditDate="2019-03-13T22:26:33.847" LastActivityDate="2019-03-13T22:26:33.847" Title="How much of Earth's surface would be covered by water if all ice melted?" Tags="|climate-change|water|glaciology|ice|sea-ice|" AnswerCount="0" CommentCount="13" ClosedDate="2019-03-14T17:47:32.893" ContentLicense="CC BY-SA 3.0" />
  <row Id="7229" PostTypeId="2" ParentId="4505" CreationDate="2016-01-11T20:08:16.557" Score="4" Body="&lt;p&gt;It mainly depends on where you are &quot;coming from,&quot; rather than where you are &quot;going to.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In September, you are &quot;coming from&quot; a hot summer. The earth has been hot &lt;em&gt;recently,&lt;/em&gt; and will take some time to cool down (in your part of the world. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In March, you are &quot;coming from&quot; a cold winter. The earth has been cold recently, and will take some time to heat up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Cold and &quot;hot&quot; are where you are &quot;going to,&quot; in September and March, respectively, but the weather on the equinox days are dictated by the &quot;rearview mirror.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Put another way, the amount of solar energy that reached the earth &quot;today&quot; is less important a factor in the heat than what happened &quot;recently&quot; or just before.&lt;/p&gt;&#xA;" OwnerUserId="42" LastActivityDate="2016-01-11T20:08:16.557" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7230" PostTypeId="1" CreationDate="2016-01-12T00:01:59.970" Score="6" ViewCount="69" Body="&lt;p&gt;I was wondering if anyone here is familiar with temperature and precipitation estimation? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I need to estimate P and T from April to July 2016. I am planning to use excel to do the calculation because  I am not familiar with programming languages. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What options do I have for the calculations? are there ready formula that I can use to estimate T and P? what historical based models are there for such problem?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks,&lt;/p&gt;&#xA;" OwnerUserId="5156" LastActivityDate="2016-01-12T00:01:59.970" Title="Near Future Precipitation and Temperature estimations?" Tags="|temperature|hydrology|precipitation|climate-models|climatology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7231" PostTypeId="2" ParentId="5233" CreationDate="2016-01-12T11:44:12.747" Score="3" Body="&lt;p&gt;What you see in marble are not veins (for example in the picture of yours). By the term vein in geology we mean a magmatic intrusion in the rock in the form of vein. Can a marble have magma real veins? Yes. The process is explained here: &lt;a href=&quot;https://en.wikipedia.org/wiki/Intrusive_rock&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Intrusive_rock&lt;/a&gt;&#xA;The 'veins' you are referring to are coming from the different beds of the rock formation. Beds form by the deposition of layers of sediment on top of each other and they might have variations in mineral composition.&#xA;As BillOer mentioned already, marble is a metamorphic rock formed from limestone. Can I have different type of 'veins' and swirls in the metamorphosed limestone in comparison with the initial limestone? YES. Why? Because during the metamorphic phase, pressure and heat is applied to the rock. So, we might have a partial melt and re - crystallization, a pressure slide forming swirls and new 'veins'.&lt;/p&gt;&#xA;" OwnerUserId="749" LastActivityDate="2016-01-12T11:44:12.747" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7232" PostTypeId="2" ParentId="4594" CreationDate="2016-01-12T17:08:49.290" Score="2" Body="&lt;p&gt;Sort answer: from what we already know, NO.&#xA;A comet (or asteroid) impact can influence mineral composition near the crater (high pressure and temperature) but this impact is small and diminishes quickly in respect of the radius. There is no documented quantitative difference of a mineral deposit versus its radius from an impact crater (not in cm and meters scale, but in km scale). Thus, we cannot assume that there is correlation between uranium deposits of Australia (or any other country) and impact craters. &#xA;Uranium deposits can be formed in many ways:&#xA;As you can see from the list, 7 out of 15 ways of uranium formation, occur in Australia. None of them due to comet impact.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;1. Intrusive deposits&lt;/strong&gt;&#xA;In South Australia, Radium Hill was mined 1954-62, and large bodies of low-grade mineralisation occur in the Olary Province.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;2. Granite-related deposits&lt;/strong&gt;&#xA;The dimensions of the openings have a wide range, from the massive veins of pitchblende at Jachymov deposit (Czech Republic), to the narrow pitchblende-filled cracks, faults and fissures in some of the ore bodies in Europe, Canada and Australia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;3. Polymetallic iron-oxide breccia complex deposits&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;4. Volcanic-related deposits&lt;/strong&gt;&#xA;In Australia, they are minor – Ben Lomond and Maureen in Qld are the most significant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;5. Metasomatite deposits&lt;/strong&gt;&#xA;Valhalla and Skal (Australia)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;6. Metamorphite deposits&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;7. Proterozoic unconformity deposits&lt;/strong&gt;&#xA;Australia (the Alligator Rivers region in the Pine Creek Geosyncline, NT and Rudall River area, WA).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;8. Collapse breccia pipe deposits&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;9. Sandstone deposits&lt;/strong&gt;&#xA;Basal channel deposits – wide channels filled with permeable sediments. Examples are Dalur and Khiagda (Russia) and Beverley and Honeymoon (South Australia).&#xA;Mafic dykes or sills in Proterozoic sandstones – Examples at Matoush (Canada) and Westmoreland (Australia).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;10. Palaeo-quartz-pebble conglomerate deposits&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;11. Surficial deposits&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;12. Lignite-coal&lt;/strong&gt;&#xA;Mulga Rock (Western Australia).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;13. Carbonate deposits&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;14. Phosphate deposits&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;15. Black shale deposits&lt;/strong&gt; &lt;/p&gt;&#xA;" OwnerUserId="749" LastEditorUserId="749" LastEditDate="2016-01-12T17:53:20.770" LastActivityDate="2016-01-12T17:53:20.770" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7233" PostTypeId="1" AcceptedAnswerId="7234" CreationDate="2016-01-12T18:30:06.293" Score="11" ViewCount="4923" Body="&lt;p&gt;Intuitively, it makes perfect sense to think that the coldest day of the year would be the day that gets the least sunshine, the winter solstice.  In the northern hemisphere, this occurs a few days before Christmas.  But as anyone who lives in places that gets snow can tell you, the most bitter parts of winter are in January and February, not December.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why does it get so much colder when sunlight (and the warmth it should be bringing with it) is increasing?&lt;/p&gt;&#xA;" OwnerUserId="341" LastActivityDate="2023-07-06T06:17:03.617" Title="Why does winter get colder after the solstice?" Tags="|climate|seasons|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7234" PostTypeId="2" ParentId="7233" CreationDate="2016-01-12T18:51:19.730" Score="13" Body="&lt;p&gt;Primarily because of &lt;strong&gt;inertia&lt;/strong&gt;.  This phenomenon is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Seasonal_lag&quot; rel=&quot;nofollow noreferrer&quot;&gt;seasonal lag&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;It is true that the December solstice is the moment that the northern hemisphere gets the lowest total amount of insolation.  Conversely, the June solstice corresponds to the moment of maximum insolation.  The oceans, and to a lesser degree the land, absorb a lot of heat.  Due to the large heat capacity of water and the large amounts of water, the seasonal lag can be considerable.  In general, mid-latitude areas near large bodies of water have the largest seasonal lag, to the extent that the warmest month of the year in most of western Europe is August.&lt;/p&gt;&#xA;&lt;p&gt;It is illustrated very well by this &lt;em&gt;Warmest day of the Year&lt;/em&gt; map that NOAA NCDC (now NCEI) produced for the contiguous United States:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/b4A5P.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/b4A5P.jpg&quot; alt=&quot;NCDC/NCEI map of warmest day of the year&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As expected, areas with a humid climate, such as southern Texas and nearby areas, tend to have the warmest day of the year in August.  The west coast is even more extreme, with some places having the warmest day in September.  Conversely, desert areas in the southwest (southern Arizona, New Mexico, western Texas) have the warmest day of the year in June.  (For the Big Bend area in Texas, it's even in the &lt;em&gt;first&lt;/em&gt; half of June, which has different reasons; I'm no expert on the climate of the region, but according to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7233/why-does-winter-get-colder-after-the-solstice/7234?noredirect=1#comment59315_7234&quot;&gt;a comment by David Hammen&lt;/a&gt;, it's &lt;em&gt;due to the North American Monsoon. July and August are much cloudier (and occasionally, much more rainy) than is June in the Big Bend area&lt;/em&gt;).&#xA;There is a corresponding map for coldest day of the year:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/46JC8.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/46JC8.jpg&quot; alt=&quot;Coldest day of the year&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;(Source: &lt;a href=&quot;https://www.ncdc.noaa.gov/news/when-to-expect-coldest-day-of-year&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCEI&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;The detailed structure is somewhat different, which has to due with local climate and circulation, but the overall trend related to humidity and proximity to ocean shows up in both.  We can also see the mountains, which I would guess to be a snow albedo feedback effect (ever notice how nights get colder when the ground is snow-covered?).  At NCEI you will also find &lt;a href=&quot;https://www.ncdc.noaa.gov/news/when-to-expect-coldest-day-of-year&quot; rel=&quot;nofollow noreferrer&quot;&gt;similar maps for the rest of the USA&lt;/a&gt; as well as &lt;a href=&quot;https://www.ncei.noaa.gov/news/when-expect-warmest-day-year&quot; rel=&quot;nofollow noreferrer&quot;&gt;updated information focussing on the 1991-2020 timeframe&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2023-07-06T06:17:03.617" LastActivityDate="2023-07-06T06:17:03.617" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="7235" PostTypeId="2" ParentId="4239" CreationDate="2016-01-12T21:33:39.410" Score="3" Body="&lt;p&gt;One option is &lt;a href=&quot;http://www.ncdc.noaa.gov/cdo-web/&quot; rel=&quot;nofollow&quot;&gt;NOAA's Climate Data Online service&lt;/a&gt;. From that page you can use the Mapping Tool, view Time-Related Maps, and select Hourly/Sub-hourly view. You can then check the Global Hourly dataset to see stations worldwide which have hourly* precipitation data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*This data (Integrated Surface Data or ISD) tends to include less than hourly temporal resolution outside of the U.S. and some major international airports, but you'll still have finer-than-daily resolution in most cases. In terms of spatial resolution, there are many stations included in this service around the world as you'll see - over 20,000 stations with better coverage (and quality data) in some areas than others. Selecting one or more of these stations and downloading their weather data provides a time-series as a digital table. Some examples:&#xA;&lt;a href=&quot;http://www.ncdc.noaa.gov/cdohtml/3505dat.txt&quot; rel=&quot;nofollow&quot;&gt;text file&lt;/a&gt;; &lt;a href=&quot;http://www.ncdc.noaa.gov/cdohtml/ishwebform.html&quot; rel=&quot;nofollow&quot;&gt;web form&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can view metadata for the CDO's Global Hourly data here: &lt;a href=&quot;https://gis.ncdc.noaa.gov/geoportal/catalog/search/resource/details.page?id=gov.noaa.ncdc:C00532&quot; rel=&quot;nofollow&quot;&gt;https://gis.ncdc.noaa.gov/geoportal/catalog/search/resource/details.page?id=gov.noaa.ncdc:C00532&lt;/a&gt; On that page it states the purpose of this dataset as:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Global Hourly Data provides a long-term record of hourly, sub-hourly and synoptic weather observations from station networks around the world. Observation sources include the World Meteorological Organization, Automated Surface Observing System, Automated Weather Observing Stations, US Climate Reference Network, and others. Weather elements observed include sky conditions, visibility, weather type, dry bulb, wet bulb, and dew point temperatures, relative humidity, wind speed and direction, wind gusts, station and sea level pressure, altimeter, and precipitation. Online data are typically delayed for 24 hours.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="4789" LastActivityDate="2016-01-12T21:33:39.410" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7236" PostTypeId="2" ParentId="7227" CreationDate="2016-01-13T04:16:42.373" Score="2" Body="&lt;p&gt;The question is not exactly clear. Are you asking about the different methods used to analyse the rock, or are you asking about using closed (aka compositional) data in a bivariate plot?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Using different methods&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is just fine, as long as both methods are accurate. For instance, you can analyse a mineral for major elements (e.g. TiO&lt;sub&gt;2&lt;/sub&gt;) using an electron probe, and then use LA-ICP-MS for trace elements (e.g. Nb). If both methods are properly standardised and all possible interferences are taken care of there is no reason why the analyses should not be used together. If the analysis was not performed properly, I wouldn't trust even as single one, regardless of whether it is used in a database together with data acquired using a different method.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Closed data&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Closed data means that it has to sum to 1 or 100%, and this can cause correlations that don't necessarily mean anything. A simple example is an MgO vs FeO plot in olivine. Of course there would be a negative correlation! This type of plot would be obvious and wouldn't tell us a thing. However, in more complicated cases, this becomes less and more of a problem. It mostly depends on a case by case basis. Note that if you're comparing a major element (TiO&lt;sub&gt;2&lt;/sub&gt;) with a trace element (Nb), there is less of a problem. The trace element is not one of the components that hardly has any implications for the close problem. Whether you have 10, 20 or 100 ppm Nb will not change anything for the 5% of TiO&lt;sub&gt;2&lt;/sub&gt; you got in your rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Classic statistics done on compositional data is almost always wrong. In the past 20 years or so, a new statistical field called &quot;compositional data analysis&quot; has emerged to solve some of the problems arising from the closure problem. In short, it means that you have to transform all of your data to log-ratio form, do your stats, and transform it back. This can't solve all of the problems, however.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, the question is - do we care that it's wrong? In the vast majority of papers, there is hardly any statistics done of compositional data, and many correlations and trends are eyeballed and drawn by hand. Often, the hassle of doing statistics the correct way does not actually contribute everything. I've heard senior petrologists claim more than once that &quot;if it looks like a line, it is a line. If it doesn't, then it is not a line. I don't need the R&lt;sup&gt;2&lt;/sup&gt; and p-values for that&quot;.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-01-13T04:16:42.373" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7237" PostTypeId="2" ParentId="5233" CreationDate="2016-01-13T04:28:20.683" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;particles that go into marble (to my knowledge) don't have any noticeable elongation&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not necessarily. Marble is mostly made of either calcite (CaCO&lt;sub&gt;3&lt;/sub&gt;) or dolomite (CaMg(CO&lt;sub&gt;3&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;), both of which are carbonates that do not exhibit any foliation in metamorphic rocks. But marble is rarely pure and commonly has some clays or other minerals that can contribute to any linear features. Notice that the stuff in your picture is quite big - you can have thin layers of not-pure-marble between the pure marble.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;does it have something to do with the magma intrusions that contribute&#xA;  to the marble formation process&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Marble forms by several processes, not always related to a magma intrusion. Marble forms by heating of carbonate rocks. It could be magma and it could be other stuff.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, marble can definitely have veining. More commonly the veining is the result of hydrothermal fluids, that is mostly supercritical water flowing through the rock (in veins), dissolving some minerals and precipitating others.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sometimes you can have textures like that even without any minerals that can be foliated at all. If you take interbeds of calcite and black sand (quartz + heavy minerals, let's say magnetite) and start deforming it, you will get interesting textures. Go to Google Images and type in &quot;metamorphic deformation&quot;.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-01-13T04:28:20.683" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7238" PostTypeId="1" AcceptedAnswerId="7240" CreationDate="2016-01-13T06:42:58.897" Score="3" ViewCount="174" Body="&lt;p&gt;As someone interested in terraforming, the main obstacle to colonizing Mars is the lack of a magnetosphere and Atmosphere. To create a magnetosphere of sufficient magnitude the Martian core must be reignited. There are several ways to do this, some of which involve using electric current to restart the core, but the most feasible way it seems would be to take an asteroid of sufficient size and slingshot it into Mars. Doing so would reignite the core resulting in increased volcanic activity, the formation of a thick and stable atmosphere, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems to be the perfect solution despite the fact that doing so would be a long term investment. I was wondering - based on what we know of the Earth's development - how long would it take Mars to cool after an asteroid impact of sufficient size? are we talking millions or billions of years?&lt;/p&gt;&#xA;" OwnerUserId="5172" LastEditorUserId="192" LastEditDate="2016-01-13T16:58:42.097" LastActivityDate="2016-01-13T16:58:42.097" Title="How long would it take for Mars to cool after asteroid impact?" Tags="|geology|atmosphere|volcanology|mars|natural-disasters|" AnswerCount="1" CommentCount="4" ClosedDate="2016-01-13T10:03:34.233" ContentLicense="CC BY-SA 3.0" />
  <row Id="7240" PostTypeId="2" ParentId="7238" CreationDate="2016-01-13T08:07:06.870" Score="4" Body="&lt;p&gt;It would be interesting to read peer reviewed scientific papers that discuss the feasibility of &quot;restarting Mars' core&quot; via an asteroid impact. Some links would be appreciated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am very sceptical that it could be achieved in such a manner. Small asteroid impacts would change the topography of the surface by creating new craters and spraying crater ejecta over the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Impacts from extremely large asteroids would only create larger craters or possibly blast out large chunks of Mars and even destroy the planet: such as a collision with Ceres.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the flaws I see in trying to &quot;restart the core&quot; is how to keep a solid inner core within a molten outer core, while at the same time creating relative movement between the two.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth&amp;#39;s_magnetic_field&quot; rel=&quot;nofollow&quot;&gt;Earth's magnetic field&lt;/a&gt; exist because its solid inner iron-nickel core and the metallic molten outer core move relative to one another creating a geodynamo. Without a solid core and relative movement between the two the only thing that will be achieved will be a molten core without a magnetic field.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If it were possible to remelt the core of Mars, a magnetic field would not be created by simply remelting the core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other flaw I see is that if it were possible to remelt the core, the core will expand due to thermal expansion. This will then increase ground stresses within the overlying rock which will result in cracking of the overlying rock and the generation of Mars-quakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another flaw I see is concerns the energy required to remelt the core. A significant volume of core would need to be remelted. That would require a lot of energy over a prolonged period of time. The effect of an asteroid impact would dissipate quickly.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="725" LastEditDate="2016-01-13T14:32:48.323" LastActivityDate="2016-01-13T14:32:48.323" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7241" PostTypeId="2" ParentId="7212" CreationDate="2016-01-13T09:49:45.147" Score="2" Body="&lt;p&gt;Pure water freezes at 0 °C (32 °F) and most of the time pure water is rarely found in ponds and other open water bodies. When impurities get mixed in water its freezing point drops.&lt;/p&gt;&#xA;" OwnerUserId="5175" LastActivityDate="2016-01-13T09:49:45.147" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7242" PostTypeId="2" ParentId="7212" CreationDate="2016-01-13T10:12:02.113" Score="6" Body="&lt;p&gt;No-one has mentioned fish yet. Do you have fish or other animals in your pond? Not only do they provide a small amount of warming, their movement will help prevent ice forming.&lt;/p&gt;&#xA;" OwnerUserId="5176" LastActivityDate="2016-01-13T10:12:02.113" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7243" PostTypeId="1" AcceptedAnswerId="7248" CreationDate="2016-01-13T10:48:31.190" Score="3" ViewCount="113" Body="&lt;p&gt;I have see this morning this curious garden where one part was covered with frost while the other was frost free. &lt;a href=&quot;https://i.stack.imgur.com/KhoXo.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KhoXo.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Question 1:&#xA;What are the factor that play a role in this configuration? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My guess is radiation from the building and the wind (the frost free part being more protected from the wind by the building) but then I wonder : Will there still be these two zones after a night without any wind? (Question 2)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The left house is heated, the middle one isn't but it's inhabited, the shed is closed but not insulated and without heating source inside.&#xA;There isn't any other surrounding structures that could create shade. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The open side of the garden is facing south. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I observed the frost after sunrise, but before the sun rays were reaching the garden.  &lt;/p&gt;&#xA;" OwnerUserId="1315" LastEditorUserId="1315" LastEditDate="2016-01-15T10:45:38.347" LastActivityDate="2016-01-15T10:45:38.347" Title="The effect of buildings on frost" Tags="|temperature|wind|world-building|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7244" PostTypeId="1" AcceptedAnswerId="7249" CreationDate="2016-01-13T20:20:19.763" Score="8" ViewCount="1074" Body="&lt;p&gt;Assuming here might be someone who knows something about this, I wanted to ask what is behind this round structure I have spotted today on Google Earth:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RRNPX.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RRNPX.png&quot; alt=&quot;Google Earth map&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There seems to be a large (~200 km), nearly perfect half-circle covering the states of Alabama, Mississippi and Tennessee. How could this regular structure  possibly originate? I did some research on the web, but could not find anything. It looks a bit like an impact crater, but there is none listed in this location and especially of this large size. So how did this structure emerge?&lt;/p&gt;&#xA;" OwnerUserId="5187" OwnerDisplayName="addy2012" LastEditorUserId="6298" LastEditDate="2024-02-29T09:06:17.413" LastActivityDate="2024-02-29T09:06:17.413" Title="Round structure in southern United States" Tags="|geology|geography|satellite-oddities|" AnswerCount="5" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7246" PostTypeId="2" ParentId="7244" CreationDate="2016-01-13T20:35:34.697" Score="2" Body="&lt;p&gt;It is indeed a land use pattern, but I would guess it is driven by geology. I'm sure someone will come up with some details, but in the meantime check this wikipedia on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Geology_of_the_Appalachians&quot; rel=&quot;nofollow&quot;&gt;geology of the Appalachians&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;See how &lt;a href=&quot;https://en.wikipedia.org/wiki/Geology_of_the_Appalachians#/media/File:Appalachian_map.svg&quot; rel=&quot;nofollow&quot;&gt;this map corresponds&lt;/a&gt; to what you're seeing on the landscape. &lt;/p&gt;&#xA;" OwnerUserId="5185" LastActivityDate="2016-01-13T20:35:34.697" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7248" PostTypeId="2" ParentId="7243" CreationDate="2016-01-13T21:38:17.770" Score="2" Body="&lt;p&gt;I would say the most relevant factor involved would be &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiative_cooling&quot; rel=&quot;nofollow&quot;&gt;Radiative cooling&lt;/a&gt;, with ground areas closer to the buildings not losing as much heat energy as the buildings act to reflect some of the radiation back keeping those areas frost free, while open exposed areas lose more energy and experience frost.&lt;/p&gt;&#xA;" OwnerUserId="140" LastActivityDate="2016-01-13T21:38:17.770" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7249" PostTypeId="2" ParentId="7244" CreationDate="2016-01-14T05:49:05.450" Score="13" Body="&lt;p&gt;This is a sedimentary sequence representing the shoreline of a Cretaceous-Paleogene inland sea, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Western_Interior_Seaway&quot;&gt;Western Interior Seaway&lt;/a&gt;. You can look at the sequence of sediments laid down in the USGS &lt;a href=&quot;http://ngmdb.usgs.gov/gmna/&quot;&gt;Geological Map of North America&lt;/a&gt;. I recommend downloading the Southern Sheet in high resolution and the Explanation Sheet to explain what's going on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The land use pattern as seen by other people answering this question is actually putting the effect in front of the cause; due to the nature of these sediments being a positive influence on the fertility of the land, it is more likely to be used for farming.&lt;/p&gt;&#xA;" OwnerUserId="496" LastEditorUserId="496" LastEditDate="2016-01-14T05:55:28.810" LastActivityDate="2016-01-14T05:55:28.810" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7250" PostTypeId="1" AcceptedAnswerId="7251" CreationDate="2016-01-14T08:46:34.347" Score="5" ViewCount="482" Body="&lt;p&gt;Many people seem to complain about large wind farms. Instead of all that, there are many cities with all their tall buildings that actually 'magnify' the wind or augment it. Even corridors through a building can be a virtual wind tunnel. Why not put a lot of medium size wind-to-energy devices or small ones all over a city, wherever there is a known spot or area that augments the wind because of buildings or corridors etc.? (I even saw an old Popular Science magazine with a sci-fi style picture of a huge building with a big fan to generate energy built right in it..)&lt;/p&gt;&#xA;" OwnerUserId="1371" LastEditorUserId="39" LastEditDate="2016-01-14T09:22:01.770" LastActivityDate="2016-01-14T13:37:25.650" Title="About an alternative type of wind energy facility" Tags="|wind|human-influence|air-currents|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7251" PostTypeId="2" ParentId="7250" CreationDate="2016-01-14T09:33:42.773" Score="8" Body="&lt;p&gt;This has been tried to some extent; &lt;a href=&quot;https://en.wikipedia.org/wiki/Strata_SE1&quot; rel=&quot;noreferrer&quot;&gt;Strata&lt;/a&gt; in London was a skyscraper that was built with three wind turbines at the top, with a deliberate design to funnel wind into them. There are other examples.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mLQfB.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mLQfB.jpg&quot; alt=&quot;Picture of Strata, from Wikimedia Commons&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Siting renewable energy generation in cities is very attractive, partly because many people feel that the &quot;industrial&quot; feel fits better there, but also because it locates sources of generation close to sources demand. For some other technologies, such as photovoltaics, this is indeed a good approach. However, it doesn't tend to work out that way for wind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are three main disadvantages to urban wind:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&quot;Dirty air&quot; : Not what it literally sounds like (that's also true in cities, but wind turbines don't mind). The wind that is funnelled through, around and above buildings is sometimes accelerated, but it is also made turbulent, and wind turbines do not like turbulent flow. Turbulence increases the unwanted forces that turbines experience (i.e. forces that do not help them make electricity), and makes them less efficient.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Economies of scale: The amount of power that a wind turbine can generate, in a given wind speed, is proportional to the square of its diameter. Which is to say, size matters. In the countryside, onshore rotors commonly reach 80m diameter (offshore are much larger). In cities, this size would not be practical or acceptable. That means that a &lt;em&gt;much&lt;/em&gt; larger number of turbines would be needed to generate as much power, which would be more expensive and have more visual impact.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;It isn't all that windy: The power that a turbine of a given diameter can generate is proportional to the cube of the wind speed. Because of this, small differences in wind speed are very important to wind farms. Most cities simply do not experience such high windspeeds as rural hilltops do.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;A fourth reason may be public acceptance; while people may view a few token turbines on rooftops as a good thing, the quantity needed to make a substantial contribution to national demand would drastically change a city's skyline, and might meet with disapproval similar to many rural wind farms. However, I have no evidence for this.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2016-01-14T09:33:42.773" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7252" PostTypeId="2" ParentId="7250" CreationDate="2016-01-14T13:37:25.650" Score="5" Body="&lt;p&gt;There's just not that much kinetic energy in the air within the urban canopy layer; much of what there is, is in the form of turbulence, rather than the laminar flow that turbines harness.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, air is very low density, which means that to get a decent amount of energy out of it, we need lots of effective rotor area, and even with the funnelling effect of buildings, it's not economically viable to get the rotor area required. A lot of small-to-medium sized devices within the urban canopy layer would still produce very little energy, and would cost a lot.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, although the opposition to rural turbines is very noisy, it's also (in almost all the world) a small minority.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/jtmV6.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;sub&gt;&lt;sub&gt;&lt;a href=&quot;http://thebritishgeographer.weebly.com/urban-climates.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;&lt;/sub&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="100" LastActivityDate="2016-01-14T13:37:25.650" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7253" PostTypeId="1" AcceptedAnswerId="7263" CreationDate="2016-01-14T14:18:55.267" Score="2" ViewCount="2296" Body="&lt;p&gt;Many days I walk out to my car to go to work and notice my windows are fogged up, I believe due to dew (haha homophones). When I am at my mother's house(O'Fallon, MO), all Windows get fogged up. When I am at my father's house (Saint Charles, MO), only one side of the car is fogged up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is kind of a two-part question. 1) How does dew accumulate? 2) Why would it only accumulate on one side of my car?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suspect it has to do with the fact the side that does not fog up faces a tree. This is very curious to me. Since I am not sure what else is needed to answer my question, I will update as comments come in.&lt;/p&gt;&#xA;" OwnerUserId="5132" LastActivityDate="2016-01-15T01:36:35.033" Title="Why does dew accumlate on only one side of my car?" Tags="|temperature|water-vapour|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7254" PostTypeId="2" ParentId="96" CreationDate="2016-01-14T18:02:12.550" Score="6" Body="&lt;p&gt;An important issue to realize is that water must have been very abundant in the protosolar disc, as tobias already stated.&#xA;To expand on that I just want briefly touch upon the atomic abundances that we measure in the corona of the sun, as presented by a wikimedia-commons graph:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hlTxQ.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hlTxQ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;(Sidenote: Those abundances compare well to the revised &lt;a href=&quot;http://adsabs.harvard.edu/abs/2009ARA%26A..47..481A&quot; rel=&quot;noreferrer&quot;&gt;Asplund2009&lt;/a&gt;-abundances)&lt;br&gt;&#xA;We think that those numbers are representative of the bulk composition of the Sun, as it is only burning Helium since 4.567 Gyrs. Thus the composition is generally assumed to be primordial, or what the solar system started out with.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now let us imagine this atomic mixture accumulating around the young terrestrial planets and focus on the most abundant elements H, He, C, N and O. In a thick planetary envelope, shielded by UV, equilibrium chemistry will set in. Then a lot of $H_2$ will form, He will stay inert and C, N, O will try to react with Hydrogen, simply because the number of encounters is much higher with that, than inside of the CNO group. Some CO will form, as this is a very stable molecule.&#xA;But as C becomes depleted, and our protosolar nebula has $C/O \approx 0.5$, there is still a lot of Oxygen left. Thus it will inevitably combine to $H_2O$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The result is, that we expect there to be really &lt;em&gt;a lot&lt;/em&gt; of water around in Planet-forming discs. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The escape or destruction of water after this period however, is apparently also very efficient, and other answers have touched upon the retention of water on Earth. So in fact Astronomers at the moment rather wonder &quot;where did all the water go?&quot;&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2016-01-14T18:02:12.550" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7256" PostTypeId="1" CreationDate="2016-01-14T20:27:33.040" Score="4" ViewCount="191" Body="&lt;p&gt;I have a few P190s navigation files from a 2D reflection seismic acquisition shoot and wondering what the best way was to extract UTM's (or latitude and longitude) and depth. I am reading through the headers and trying to make the best of it, but I am having a hard time making sense of it.&lt;/p&gt;&#xA;" OwnerUserId="5204" LastEditorUserId="192" LastEditDate="2016-01-14T20:33:47.760" LastActivityDate="2016-01-16T21:38:48.110" Title="Where to start with P190s Seismic Navigation Files?" Tags="|geophysics|oceanography|seismic|data-formats|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7261" PostTypeId="2" ParentId="6668" CreationDate="2016-01-14T22:14:13.253" Score="0" Body="&lt;p&gt;I agree with Agata that it is stratocumulus. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This link talks about cloud types&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://oceanservice.noaa.gov/education/yos/resource/JetStream/synoptic/clouds_max.htm&quot; rel=&quot;nofollow&quot;&gt;NWS JetStream&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5076" LastActivityDate="2016-01-14T22:14:13.253" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7262" PostTypeId="2" ParentId="7200" CreationDate="2016-01-14T23:38:22.277" Score="3" Body="&lt;p&gt;Here is a link to a hydrochemical consultant, Dr. C.A.J. Appelo, and the public-domain software FREEQC.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It can be downloaded from &lt;a href=&quot;http://www.hydrochemistry.eu/&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This link leads to an &lt;a href=&quot;http://www.hydrochemistry.eu/exmpls/sea_evap.html&quot; rel=&quot;nofollow&quot;&gt;example&lt;/a&gt; of salt precipitation rates when evaporating sea water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The formulation used is detailed in a second &lt;a href=&quot;http://www.hydrochemistry.eu/ph3/manual2_eqns.pdf&quot; rel=&quot;nofollow&quot;&gt;manual&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5076" LastEditorUserId="1379" LastEditDate="2016-01-15T12:41:13.120" LastActivityDate="2016-01-15T12:41:13.120" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7263" PostTypeId="2" ParentId="7253" CreationDate="2016-01-15T01:36:35.033" Score="6" Body="&lt;p&gt;The formation of &lt;a href=&quot;https://en.wikipedia.org/wiki/Dew_point&quot;&gt;dew&lt;/a&gt; is due to atmospheric moisture and temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given that dew forms on all sides of your car at your mother's house, this makes me think the car is more exposed at you mother's house so that the car is uniformly cold and the temperature of the car is at, or below, the dew point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With dew only forming on one side of the car when at your father's house, this tends to infer there is a temperature difference between each side of the car; with the side of the car on which due forms being colder.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You mention that dew does not form on the side of the car facing a tree. If the tree is sufficiently large and leafy (bushy) and the car is close enough to the tree, the tree can shield the car from the cold air thus making that side of the car slightly warmer than the other side of the car. As long as the temperature is above the dew point, due will not form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Dew point varies for atmospheric moisture content, temperature and air pressure.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-01-15T01:36:35.033" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7265" PostTypeId="2" ParentId="7244" CreationDate="2016-01-15T11:01:50.030" Score="4" Body="&lt;p&gt;The clue is its location at the southwestern end of the Appalachians. Compressive mountains have to terminate somewhere, somehow. In this case the differential strain energy between the Appalachians and the Alabama-Mississippi sedimentary trough has been taken up by deformation of the softer younger sediments. Browse through mountain chain terminations on Google Earth, and you may find other examples (e.g. Carpathians, north east Iran) although your example is one of the clearest.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-01-15T11:01:50.030" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7266" PostTypeId="1" CreationDate="2016-01-15T11:21:00.673" Score="12" ViewCount="17962" Body="&lt;p&gt;On the &lt;a href=&quot;https://earthquake.usgs.gov/learn/glossary/?term=Richter%20scale&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS website&lt;/a&gt;, it says&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Because of the logarithmic basis of the scale, each whole number&#xA;  increase in magnitude represents a tenfold increase in measured&#xA;  amplitude;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However my book says this:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Like many other scales in science (decibel is another example), Richter scale is not linear. This means that an earthquake of magnitude 6 does not have one and half times the destructive energy of an earthquake of magnitude 4. In fact, an increase of 2 in magnitude means 1000 times more destructive energy. Therefore, an earthquake of magnitude 6 has thousand times more destructive energy than an earthquake of magnitude 4.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But based upon the USGS information, an increase in 2 magnitude would be 10 x 10 = 100 stronger.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now which one is correct?&lt;/p&gt;&#xA;" OwnerUserId="5208" LastEditorUserId="1149" LastEditDate="2017-02-13T03:43:45.790" LastActivityDate="2017-12-30T02:18:34.887" Title="How to compare earthquake magnitudes" Tags="|earthquakes|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7268" PostTypeId="2" ParentId="2931" CreationDate="2016-01-15T12:00:07.150" Score="8" Body="&lt;p&gt;The present consensus is that the Messinian salinity crisis (MSC) took place in &lt;strong&gt;5 stages&lt;/strong&gt;: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;0)&lt;/strong&gt; Mediterranean restriction from the ocean; &lt;strong&gt;1)&lt;/strong&gt; Primary gypsum precipitation (starting 5.97 million years ago) at the margins of the Mediterranean, still fed by Atlantic water; &lt;strong&gt;2)&lt;/strong&gt; Halite precipitation (more than 1 km thick, mostly in the abyssal areas); &lt;strong&gt;3)&lt;/strong&gt; Possibly a partial desiccation during a full disconnection from the ocean; &lt;strong&gt;4)&lt;/strong&gt; Geologically-rapid restoration of normal marine conditions, 5.33 million years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Known &lt;strong&gt;disagreements&lt;/strong&gt; are: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;*Whether 2 and 3 are in that order or the inverse. And their duration, ranging from a few tens of thousands to a few hundred of thousand years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;*Whether 3 involves a km-scale sea-level drawdown or only a few tens or a hundred meters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*Whether 4 took place in a single catastrophic event or in a few tens of thousand years[&lt;a href=&quot;http://mappingignorance.org/2014/02/07/how-the-mediterranean-was-refilled/&quot; rel=&quot;nofollow noreferrer&quot;&gt;4&lt;/a&gt;][&lt;a href=&quot;http://www.nature.com/nature/journal/v462/n7274/full/nature08555.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;5&lt;/a&gt;].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the &lt;strong&gt;causes&lt;/strong&gt;, there is a widespread agreement that these events were the result of a relative dry climate (evaporation exceeding precipitation in the Mediterranean) in combination with the &lt;strong&gt;tectonic vertical motions of the Gibraltar Arc&lt;/strong&gt; (Betics and Rif) and the &lt;strong&gt;global sea-level changes&lt;/strong&gt;, but disagreement remains as to what mechanism is more relevant. I can add here the role of &lt;a href=&quot;http://retosterricolas.blogspot.com/2011/10/messinian-salinity-crisis-13-salt-all.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;climatically-controlled erosion&lt;/strong&gt;&lt;/a&gt; along the connecting corridor: for example: during Stage 1, the tectonic uplift of the seaways should have competed with the erosion produced by the inflowing water from the Atlantic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, none of the above is accepted by all researchers, but a good reference (though quite technical) for this &lt;em&gt;consensus&lt;/em&gt; is probably this report from the 2007 CIESM international meeting in Almería, Spain: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Briand, F. (ed.) The Messinian Salinity Crisis from Mega-Deposits to&#xA;  Microbiology – A &lt;strong&gt;Consensus Report&lt;/strong&gt; (CIESM Workshop Monographs 30,&#xA;  &lt;strong&gt;CIESM, 2008&lt;/strong&gt;).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But let me add some more thinking: As the question correctly states, in the 70's, deep drillings carried out on board the Glomar Challenger proved the presence of salt deposits offshore Mallorca, demonstrating that the classical onshore salt outcrops had an equivalent in the open sea, and providing direct sampling of a great evaporitic basin in the deeper inner parts of the sea. But this had already been seen earlier through seismic profiling since the 60s. The IODP expeditions did find unprecedented anhydrites and rounded pebbles in what was supposed to be the deeper parts of the Messinian Mediterranean, and the interpretation was that the Mediterranean went nearly dry and became a set of brackish lakes (remnants of a desiccated Med) towards which rivers in the dry seafloor were flowing. But these are weak evidence and both are indeed strongly contested. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Importantly, the presence of salt does not necessarily imply a desiccation or a large drawdown of the Med, and that's the main source of the debate. Note that to increase the salinity of the Mediterranean it only takes a reduction of the outflow, whereas in order to make it dry, it also requires cancelling the inflow from the Atlantic. Artificial salt pans, for example, evaporate sea water keeping the brine at a constant level, maintained by further inflow of seawater. Furthermore, as early as 1849, italian chemist J. Usiglio described in detail how, although the sea salt contains ten times more halite than gypsum, it is gypsum that precipitates first due to its lesser solubility. This may explain the abundance of gypsum onshore the Mediterranean, in contrast with the relative scarcity of onshore halite, which seems to have deposited only in the deeper parts of the Med.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hZziV.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hZziV.png&quot; alt=&quot;Section across the Nile in Aswan (Egypt) by Chumakov (1967), based on wells. It shows a valley excavated by the river during the MSC, now filled with later sediments.&quot;&gt;&lt;/a&gt;&#xA;&lt;strong&gt;Section across the Nile in Aswan (Egypt) by Chumakov (1967), based on wells. It shows a valley excavated by the river during the MSC, now filled with later sediments. Following to the most extended interpretation, this valley was excavated by the Nile River due to the ~2000m lowering of the level of the Mediterranean, during the Messinian salinity crisis.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main evidence really supporting a large level fall of the Mediterranean had arrived actually somewhat earlier than the drillings, back in the late 1950s. The building of the Aswan Dam (1,200 km upstream from Alexandria) was disturbed by the discovery of a deep narrow gorge excavated in granite, hundreds of metres below sea level (Chumakov, 1967). This gorge has been since filled by loose Pliocene sediment that hindered the construction of the dam. It is now known that the gorge follows and deepens downstream the Nile, reaching around 2000 m deep below Cairo. The Rhone, Ebro and Po rivers formed also similar gorges, now buried under their present deltas, under post-Messinian sediment. In contrast with other submarine canyons formed in the margins of the continents (linked to turbidity currents originated underwater at the continental shelf), the Messinian ones along the Mediterranean coast share many characteristic with river valleys (Loget et al., 2006, Urgeles et al., 2010).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oAhOs.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oAhOs.jpg&quot; alt=&quot;Fluvial valley excavated in the seafloor during the Messinian, presumably during a dramatic lowering of the sea level. It has been found today buried under several kilometers of Plioquaternary sediment.&quot;&gt;&lt;/a&gt;&#xA;&lt;strong&gt;Fluvial valley excavated in the seafloor during the Messinian, presumably during a dramatic lowering of the sea level. It has been found in 2012 buried under several kilometers of post-Messinian sediment, thanks to 3D high-resolution seismic reflection techniques.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nevertheless, this evidence is also contested, based on other mechanisms that may also explain such erosional surfaces (see f.e., Roveri et al., Am.J.Sci., 2014). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I wrote a popular science article on this, a kind of &lt;a href=&quot;http://retosterricolas.blogspot.com/2011/10/messinian-salinity-crisis-13-salt-all.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;introduction to the Messinian salinity crisis&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Some other selected technical references here:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Krijgsman, W., Hilgen, F., Raffi, I., Sierro, F., &amp;amp; Wilson, D. (1999).&#xA;  Chronology, causes and progression of the Messinian salinity crisis&#xA;  Nature, 400 (6745), 652-655 DOI: 10.1038/23231&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Duggen, S., Hoernle, K., van den Bogaard, P., Rüpke, L., &amp;amp; Phipps&#xA;  Morgan, J. (2003). Deep roots of the Messinian salinity crisis Nature,&#xA;  422 (6932), 602-606 DOI: 10.1038/nature01553&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Govers, R. (2009). Choking the Mediterranean to dehydration: The&#xA;  Messinian salinity crisis Geology, 37 (2), 167-170 DOI:&#xA;  10.1130/G25141A.1&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Garcia-Castellanos D, Villaseñor A (2011). Messinian salinity crisis&#xA;  regulated by competing tectonics and erosion at the Gibraltar arc.&#xA;  Nature, 480 (7377), 359-63 PMID: 22170684&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="1379" LastEditorUserId="1379" LastEditDate="2016-04-11T09:18:12.913" LastActivityDate="2016-04-11T09:18:12.913" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7269" PostTypeId="1" CreationDate="2016-01-15T17:56:26.537" Score="2" ViewCount="221" Body="&lt;p&gt;If I use a really big drill and drill all the way down to a magma chamber what exactly would happen? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From what I understand we cant drill to a Magma Chamber because it is really hot, but I have a slight feeling something like shaking a soda and opening it may happen in a magma chamber due to the large amount of pressure that it is under.&lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="725" LastEditDate="2016-01-22T00:53:32.857" LastActivityDate="2016-01-22T00:53:32.857" Title="Volcano magma chamber" Tags="|geology|volcanology|volcanic-hazard|magmatism|drilling|" AnswerCount="1" CommentCount="6" ClosedDate="2016-01-21T19:58:14.860" ContentLicense="CC BY-SA 3.0" />
  <row Id="7270" PostTypeId="1" AcceptedAnswerId="7277" CreationDate="2016-01-15T20:52:42.680" Score="1" ViewCount="68" Body="&lt;p&gt;In December, the the vast part of the world community has agreed on the tackling of climate change. This was the result of the 2015 United Nations Climate Change Conference, commonly abbreviated to COP 21 (&lt;a href=&quot;https://en.wikipedia.org/wiki/2015_United_Nations_Climate_Change_Conference&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/2015_United_Nations_Climate_Change_Conference&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All media have quoted the goal to stay below 2.0°C and that the world community is even aiming for a global warming change of less than 1.5°C. However, I could not find much information on the reference period. Some time ago I've read about the period 1961 to 1990; Wikipedia states (without reference) that it's compared to pre-industrial levels. Does anyone have further information (with references) on the question, what the reference period for the COP21 agreement is?&lt;/p&gt;&#xA;" OwnerUserId="5213" LastActivityDate="2016-01-16T18:44:54.047" Title="Is there a defined reference period for the COP21 agreement?" Tags="|climate|climate-change|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7271" PostTypeId="2" ParentId="5253" CreationDate="2016-01-15T22:46:33.990" Score="12" Body="&lt;p&gt;I will attempt at rephrasing your interesting question after these considerations:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;At the continental scale, flowing water has no significant inertia, so water flows following the &lt;strong&gt;maximum slope&lt;/strong&gt;. A river is just a path along the continent that follows the maximum local slope at any of the places it passes through.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;What amazes you (let me interpret) is that continents are mostly drained by rivers that flow &lt;strong&gt;continuously&lt;/strong&gt; &lt;em&gt;downslope&lt;/em&gt;. When water lacks a downslope path ahead (local topographic minimum), it forms a lake. So, the striking thing is that there are relatively few such topographic minima, lakes or marshes, in our continents. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;If the river ends in the ocean, the fact that it is long is just imposed by the size of the continent and its sinuosity. If it ends in an endorheic (closed, internally-drained, intracontinental) basin, then by definition the river will form a lake at the lowest spot of the basin.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Because continents are above the level of the surrounding ocean, it is clear that between any location at the continent and the coast, every path will be, on average, downslope. Continental areas below sea level are by definition endorheic (see 3) and therefore they drain to internally-drained lakes. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Provided some slope, erosion makes the river network gradually entrench the terrain at typical rates of 0.01 to 1 mm/yr. Rivers move laterally more easily at very flat regions, where they loose energy and deposit their sediment load, forming meanders and marshes. Over geological time, the river network, together with other &lt;em&gt;surface transport&lt;/em&gt; processes, make the landscape decay towards a flat (peneplain) surface at the level of the ocean. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;So what would be the opposite to a landscape dominated by long rivers? Answer: Having many locations with no downhill slope to follow, topographic minima (basins) where &lt;strong&gt;lakes&lt;/strong&gt; form. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore your question reduces to this one: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&quot;Why aren't there more lakes?&quot;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The 117 million lakes on Earth occupy only 4% of the land surface[1]. The rest of the continental surface has a downhill slope for water to flow. Even endorheic drainage basins are drained mostly by rivers, although these drain to close lakes instead of the ocean. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Importantly, large lakes are relatively rare because they are ephemeral: once they form by tectonic and geodynamic changes of the topography they tend to disappear due to two processes:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A) Lake basins tend to fill up with the sediment carried by tributary rivers[2]. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;B) Lake basins tend to be lowered in level due to the erosion along their outlet river[3], see my point #5 above. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider a landscape formed with a purely random topography. It will contain many lakes because their steepest descent path will not lead to the sea. Processes A and B would tend to fill the lakes and erode their outlets, making this topographic minima disappear and establishing a &lt;em&gt;normal&lt;/em&gt; fluvial network with progressively fewer lakes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;On Earth, erosion is a process trying to remove lake basins in timescales of hundreds of thousands to tens of millions of years, depending on the size or elevation of the lake and its drainage basin. If we still have this 4% of the planet surface occupied by lakes it is because river erosion competes with relief-generating mechanisms such as plate tectonics or glaciers. But that's a different story. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1]: National Geographic: &lt;a href=&quot;http://voices.nationalgeographic.com/2014/09/15/117-million-lakes-found-in-latest-world-count/&quot; rel=&quot;nofollow noreferrer&quot;&gt;117 Milion lakes in the planet&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[2]: Carroll, A.R., and Bohacs, K.M., 1999, Stratigraphic classification of ancient lakes: Balancing tectonic and climatic controls: Geology, v. 27, p. 99–102, doi:10.1130/0091-7613(1999)027&amp;lt;0099:SCOALB&gt;2.3.CO;2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[3]: Garcia-Castellanos, D., 2006. Long-term evolution of tectonic lakes: Climatic controls on the development of internally drained basins. In: Tectonics, Climate, and Landscape evolution. Eds.: S.D. Willett, N. Hovius, M.T. Brandon &amp;amp; D.M. Fisher. GSA Special Paper 398. 283-294. doi:10.1130/2006.2398(17)&lt;/p&gt;&#xA;" OwnerUserId="1379" LastEditorUserId="6298" LastEditDate="2017-11-07T23:18:24.067" LastActivityDate="2017-11-07T23:18:24.067" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7272" PostTypeId="1" CreationDate="2016-01-15T23:35:13.130" Score="10" ViewCount="674" Body="&lt;p&gt;The Iberian peninsula lies more than 600 m above sea level, on average, far above similar geological regions in western Europe. Even tectonically undeformed areas in the inner basins present a topography and a sedimentary infill sometimes higher than 1000 m. Why?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The elevation of continents is generally thought to be the result of the isostatic equilibrium (Archimedes balance) of the crust floating on a fluid mantle (Pratt and Airy models, late XIX century). The thicker the crust (which is less dense than the mantle), the higher topography. The denser the crust, the lower the topography. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/f/fa/Airy_Isostasy.jpg&quot; width=&quot;400&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Cartoon explaining the concept of &lt;em&gt;isostatic equilibrium&lt;/em&gt;, according to which topography (h1) is sustained by a &lt;em&gt;crustal root&lt;/em&gt; (b1) in the same way that the elevation of an iceberg reflects the size of its submerged part.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the crust of the Iberian Peninsula is about 30-33 km thick on average, similar to most of the western european platform, and nothing suggests that the Iberian crust has a lower density than other regions. Why then is the topography of Iberia higher than 600 m, in contrast with the near sea-level western Europe?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, the underlying question is: why Iberia is 600m higher than the W European Platform, having its Moho (base of the crust) shallower?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/B45rM.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/B45rM.png&quot; alt=&quot;Topographic map of Europe&quot;&gt;&lt;/a&gt;&#xA;&lt;strong&gt;Topographic map of Europe&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cc9yV.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cc9yV.jpg&quot; alt=&quot;Depth to the base of the crust in Europe (from Tesauro et al., 2008)&quot;&gt;&lt;/a&gt;&#xA;&lt;strong&gt;Depth to the base of the crust in Europe (in km; from Tesauro et al., 2008)&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="1379" LastEditorUserId="1379" LastEditDate="2016-01-17T08:06:41.803" LastActivityDate="2016-01-17T08:06:41.803" Title="Why is the elevation of the Iberian Peninsula so high?" Tags="|geophysics|geology|geography|geodynamics|topography|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7273" PostTypeId="2" ParentId="7272" CreationDate="2016-01-16T13:36:28.437" Score="2" Body="&lt;p&gt;I don't know for sure, but my guess is that at least a part of the high Iberian elevation is due to NNE-SSW compression in northeast Spain, caused by rotation of the Iberian block. That is,the same rotation that opened up the Bay of Biscay deep basin, whilst compressing the Pyrennean mountains. The gentle dip of most of Iberia towards the southwest would fit well with such an explanation.&#xA;But then you may ask: 'Why is there a low elevation sedimentary basin just southwest of the Pyrenees?' Check the age of sediments in this trough. I would bet they are pretty recent, and I suspect that there may well be some late-stage counter-rotation caused by the  relative east-west displacement along the Rif-Betic arc.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-01-16T13:36:28.437" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7274" PostTypeId="2" ParentId="7269" CreationDate="2016-01-16T13:47:49.580" Score="2" Body="&lt;p&gt;You might get a lava seepage, but I doubt it. The cross-sectional area of a borehole is small compared to the total cross sectional area of fractures that are there already. Note that volcanoes bulge quite markedly due to lava up-welling and deformation due to magma pressure, so the volcano is invariably well fractured. A small hole is likely to fill up with magma rapidly, which would cool and solidify against the country rock, thereby plugging the hole - unless the borehole was very close to a gassy magma chamber. However, there might be exceptions in that very small fraction of volcanoes that are of the 'Plinian' type, in which exceptionally high gas pressures can occur. But then, nobody in their right mind would drill into a potentially Plinian type of volcano!&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-01-16T13:47:49.580" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7275" PostTypeId="2" ParentId="7272" CreationDate="2016-01-16T17:24:33.237" Score="1" Body="&lt;p&gt;A combination of the Opening Atlantic and push of Africa...my guess is failure of the ocean-continent contact of western Iberia in a couple of million years leading to subduction...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If no hints for differences in density, the elevation must be sustained by external forces. In this sw corner of Eurasia the only continent-continent collision between Africa and Eurasia occurs, west of Arabian plate. And the Ridge Push from Atlantic opening is significant large as well.&lt;/p&gt;&#xA;" OwnerUserId="5216" LastEditorUserId="5216" LastEditDate="2016-01-16T18:47:12.560" LastActivityDate="2016-01-16T18:47:12.560" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7276" PostTypeId="1" CreationDate="2016-01-16T18:07:42.027" Score="12" ViewCount="270" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Hurricane_Alex_%282016%29&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hurricane Alex&lt;/a&gt; (developed from an area of low pressure which began in the Atlantic near Bahamas in January 2016, and developed subtropical and later tropical storm characteristics to the south of the Azores) clearly way outside the usual &lt;a href=&quot;https://earthscience.stackexchange.com/questions/811/why-is-the-atlantic-hurricane-season-defined-as-being-between-june-1-and-novembe&quot;&gt;Jun-Nov hurricane season&lt;/a&gt;. How is it possible that such an energetic event forms during the North Atlantic winter? Clearly, this kind of hurricane is not common (previous one &lt;a href=&quot;https://en.wikipedia.org/wiki/1938_Atlantic_hurricane_season#Hurricane_One&quot; rel=&quot;nofollow noreferrer&quot;&gt;in 1938&lt;/a&gt;). What are the oceanic and atmospheric conditions necessary for the formation of Hurricane Alex?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2017-06-30T04:08:59.063" Title="How is it possible that a Hurricane such as Alex forms in the Atlantic in winter?" Tags="|atmosphere|tropical-cyclone|atlantic|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7277" PostTypeId="2" ParentId="7270" CreationDate="2016-01-16T18:44:54.047" Score="0" Body="&lt;p&gt;It's relative to the immediately pre-industrial years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As per the &lt;a href=&quot;http://newsroom.unfccc.int/unfccc-newsroom/finale-cop21/&quot; rel=&quot;nofollow&quot;&gt;press-release from the UNFCCC on COP21&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The universal agreement’s main aim is to keep a global temperature rise this century well below 2 degrees Celsius and to drive efforts to limit the temperature increase even further to 1.5 degrees Celsius above pre-industrial levels.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="100" LastActivityDate="2016-01-16T18:44:54.047" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7278" PostTypeId="2" ParentId="7272" CreationDate="2016-01-16T20:34:22.063" Score="1" Body="&lt;p&gt;A more localised, and not applicable to the whole of Iberia, but perhaps worth a mention might be the proposed &lt;a href=&quot;https://en.wikipedia.org/wiki/Delamination_(geology)&quot; rel=&quot;nofollow&quot;&gt;crustal delamination&lt;/a&gt; of southern Spain.&lt;/p&gt;&#xA;" OwnerUserId="140" LastActivityDate="2016-01-16T20:34:22.063" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7279" PostTypeId="2" ParentId="7256" CreationDate="2016-01-16T21:38:48.110" Score="1" Body="&lt;p&gt;It should be easy to spot the lat and lon coordinates. Have you found the spec? &lt;a href=&quot;http://www.seg.org/documents/10161/77915/ukooa_p1_90.pdf&quot; rel=&quot;nofollow&quot;&gt;http://www.seg.org/documents/10161/77915/ukooa_p1_90.pdf&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="8" LastActivityDate="2016-01-16T21:38:48.110" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7280" PostTypeId="1" CreationDate="2016-01-17T12:20:24.650" Score="6" ViewCount="751" Body="&lt;p&gt;I am wondering what is measured in the plots of change of precession, e.g. when describing Milankovitch Cycles. The values typically vary between .06 and −.06. I am also wondering about what the different values for extreme points mean, but that will probably be answered with the first question.&lt;/p&gt;&#xA;" OwnerUserId="5222" LastEditorUserId="94" LastEditDate="2016-04-07T08:07:44.570" LastActivityDate="2016-04-08T08:20:27.403" Title="What does the precessional parameter measure?" Tags="|climate|paleoclimatology|milankovitch-cycles|orbit|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7281" PostTypeId="1" AcceptedAnswerId="7364" CreationDate="2016-01-17T15:43:10.590" Score="0" ViewCount="1383" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NYgT1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NYgT1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;From a viewer's standpoint, when the moon starts to rise at the horizon, is the moon at the furthest distance from the viewer visually? The Moon differs from most satellites of other planets in that its orbit is close to the plane of the ecliptic, and not to Earth's equatorial plane. Remember the moon orbits the earth not the viewer.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="4617" LastEditorUserId="2570" LastEditDate="2016-05-31T13:36:08.640" LastActivityDate="2016-05-31T13:36:08.640" Title="What is the Moon's distance from viewer at horizon?" Tags="|moon|orbit|horizon|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7282" PostTypeId="2" ParentId="7276" CreationDate="2016-01-17T19:20:52.330" Score="6" Body="&lt;p&gt;Alex was a weird development, being only the second ever recorded in any month to form north of 30°N and east of 30°W, the only other being &lt;a href=&quot;https://en.wikipedia.org/wiki/Hurricane_Vince&quot; rel=&quot;nofollow&quot;&gt;Hurricane Vince&lt;/a&gt; in 2005. It developed over waters cooler than normally required for tropical development at 20-22°C, however upper level air was remarkably cold for the latitude above where Alex developed, giving a strong temperature gradient which allowed convection to consolidate and form a warm core tropical hurricane. For references see Bob Henson at Wunderground &lt;a href=&quot;http://www.wunderground.com/blog/JeffMasters/astounding-alex-hits-the-azores-januarys-first-atlantic-landfall-i&quot; rel=&quot;nofollow&quot;&gt;Astounding Alex...&lt;/a&gt;,  &lt;a href=&quot;http://www.wunderground.com/blog/JeffMasters/alex-becomes-the-atlantics-first-january-hurricane-since-1955&quot; rel=&quot;nofollow&quot;&gt;Alex Becomes...&lt;/a&gt; Temperatures in the upper atmosphere in that area were extremely cold, down to around minus -60 degrees Celsius, or minus -76 degrees Fahrenheit. &lt;a href=&quot;http://mashable.com/2016/01/14/hurricane-alex-forms-january/&quot; rel=&quot;nofollow&quot;&gt;Andrew Freeman, Mashable&lt;/a&gt; Specifically the upper troposphere (6 miles up).&lt;a href=&quot;http://blogs.channel4.com/liam-dutton-on-weather/hurricane-alex-earliest-atlantic-hurricane-1938/9608&quot; rel=&quot;nofollow&quot;&gt;Liam Dutton&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="140" LastEditorUserId="140" LastEditDate="2016-01-26T21:43:56.333" LastActivityDate="2016-01-26T21:43:56.333" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7283" PostTypeId="1" AcceptedAnswerId="7308" CreationDate="2016-01-18T04:52:58.020" Score="47" ViewCount="275574" Body="&lt;p&gt;I would like to ask that at what distance from the Earth's surface the curvature of the Earth is visible. What layer of the atmosphere is this? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yPomB.png&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yPomB.png&quot; alt=&quot;Earth Horizon like this&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've noticed that at the height of 9-12 Km (the view from from aeroplanes) it is not visible. &lt;/p&gt;&#xA;" OwnerUserId="5093" LastEditorUserId="39" LastEditDate="2016-01-18T08:05:07.950" LastActivityDate="2019-10-23T09:43:09.750" Title="How high must one be for the curvature of the earth to be visible to the eye?" Tags="|earth-observation|horizon|" AnswerCount="7" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7284" PostTypeId="2" ParentId="7283" CreationDate="2016-01-18T11:21:07.013" Score="8" Body="&lt;p&gt;Further to DrGC's excellent answer, a subjective assessment of visibility of the Earth's curvature can be gleaned from pilot's experioence over many decades. These can be summarized as:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Commercial aircraft normal maximum ceiling of 13.7 kilometres : The curvature isn't apparent. &lt;/li&gt;&#xA;&lt;li&gt;Concorde's ceiling was 18.3 kilometres, and reports are inconsistent. Some couldn't see the curvature, even though they were looking for it. Some pilots thought they could see it. Some passengers could see it after several glasses of champagne. &lt;/li&gt;&#xA;&lt;li&gt;U2 pilots could generally see the curvature at 23 kilometres, and SR71 pilots could definitely see it at 25.9 kilometres.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2016-09-22T02:18:20.090" LastActivityDate="2016-09-22T02:18:20.090" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7286" PostTypeId="2" ParentId="7276" CreationDate="2016-01-18T11:41:27.377" Score="7" Body="&lt;p&gt;Alex was an out of season freak event that bucked the trend and broke all the rules. As hurricanes go, it was somewhat weak, and could never have strengthened beyond category 1. Three conditions made it happen (i) there was an unusually strong vortex over Cuba which kick-started the rotation, (ii) the high level atmospheric shear, which usually kills off fledgling hurricanes, just didn't appear on this occasion, (iii) the storm initially followed the Gulf Stream Drift, and hence gained energy from higher than usual sea surface temperatures - though still a lot cooler than normal. After the hurricane reached central north Atlantic it veered off to the northwest, where it met much colder sea-surface temperatures. It was this cold water that killed it off. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-01-18T11:41:27.377" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7287" PostTypeId="2" ParentId="7283" CreationDate="2016-01-18T11:52:43.360" Score="24" Body="&lt;p&gt;A quick Google turned up a published article answering precisely this question (Lynch, 2008). The abstract states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Reports and photographs claiming that visual observers can detect the curvature of the Earth from high mountains or high-flying commercial aircraft are investigated. Visual daytime observations show that the minimum altitude at which curvature of the horizon can be detected is at or slightly below 35,000 ft, providing that the field of view is wide (60°) and nearly cloud free. The high-elevation horizon is almost as sharp as the sea-level horizon, but its contrast is less than 10% that of the sea-level horizon. Photographs&#xA;  purporting to show the curvature of the Earth are always suspect because virtually all camera lenses project an image that suffers from barrel distortion. To accurately assess curvature from a photograph, the horizon must be placed precisely in the center of the image, i.e., on the optical axis.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Note that the given minimum of 35,000 feet (10.7 km) is a plausible cruise altitude for a commercial airliner, but you probably shouldn't expect to see the curvature on a typical commercial flight, because:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;10.7 km is the bare minimum for seeing curvature, so the apparent curvature will be very slight at this altitude.&lt;/li&gt;&#xA;&lt;li&gt;10.7 km is near the upper end of the usual range of commercial cruise altitudes. Many flights won't get this high, and very few will go significantly higher.&lt;/li&gt;&#xA;&lt;li&gt;A passenger window may not give the necessary 60° field of view, especially if you're over the wing.&lt;/li&gt;&#xA;&lt;li&gt;As the quotation states, you need a nearly cloud-free horizon to perceive the curvature.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Lynch, D. K. (2008). &lt;a href=&quot;http://thulescientific.com/Lynch%20Curvature%202008.pdf&quot; rel=&quot;noreferrer&quot;&gt;Visually discerning the curvature of the Earth&lt;/a&gt;. &lt;em&gt;Applied Optics&lt;/em&gt;, 47(34), H39-H43.&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2017-04-30T08:53:53.753" LastActivityDate="2017-04-30T08:53:53.753" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7290" PostTypeId="1" CreationDate="2016-01-18T16:24:38.530" Score="4" ViewCount="141" Body="&lt;p&gt;I posted this question on Aviation Stack Exchange &lt;a href=&quot;https://aviation.stackexchange.com/q/24373/13007&quot;&gt;here&lt;/a&gt;.  One of the responses suggested that I post my question on Earth Science Stack Exchange.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I need a source that reports necessary current cloud data to determine &#xA;  &lt;strong&gt;cloud height&lt;/strong&gt; or &lt;strong&gt;cloud type&lt;/strong&gt; (Cirrus, Stratus, Cumulus, etc.).  I do not need historical data and, for now, I do not need forecast data.  Current data only.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I found a question/answer for determining the bottom of the cloud but I can't find it again.  I found some relative information in Aviation Stack Exchange and one answer &lt;a href=&quot;https://aviation.stackexchange.com/q/8683/13007&quot;&gt;here&lt;/a&gt; that tells how to find the cloud tops but I'm posting this question anyway in case there is resource yet to be suggested.  I'm giving up on the idea of an API but still hopeful that there are some resources and techniques we can use to acquire this information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;BTW:&lt;/strong&gt;  I am not a weather specialist.  I am a Software Engineer and we need this information for Ballistic Missile accuracy.  We need to know the weather conditions but cloud data is the most important and yet missing piece.&lt;/p&gt;&#xA;" OwnerUserId="5226" LastEditorUserId="-1" LastEditDate="2017-04-13T13:00:02.243" LastActivityDate="2016-06-10T02:09:35.163" Title="Best sources / methods to find additional cloud information for current weather conditions?" Tags="|meteorology|atmosphere|clouds|weather-forecasting|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7291" PostTypeId="2" ParentId="1092" CreationDate="2016-01-18T23:42:23.810" Score="1" Body="&lt;p&gt;ACCA Manual J: Residential Load Calculation, look in the back and they have a table of BIN temperatures for most U.S. Cities.&lt;/p&gt;&#xA;" OwnerUserId="5227" LastActivityDate="2016-01-18T23:42:23.810" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7292" PostTypeId="1" CreationDate="2016-01-19T02:53:12.930" Score="9" ViewCount="7116" Body="&lt;p&gt;As we know, when large scale volcanic eruptions occurs, large amounts of ashes and lava rushed out at short time, is it possible to drill some canels or bomb some holes in the crater so that the gas or lava can leak out slower in stead of rushing out quickly and hence reduce the scale of volcanic eruption?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="725" LastEditDate="2016-01-22T00:52:49.657" LastActivityDate="2024-01-31T17:03:14.990" Title="Can we reduce the scale of volcanic eruptions by drilling some canals or bombing some holes in the crater?" Tags="|volcanology|volcanic-hazard|drilling|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7293" PostTypeId="2" ParentId="7292" CreationDate="2016-01-19T03:50:08.953" Score="3" Body="&lt;p&gt;The general answer is no.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two critical factors that govern how a volcanic eruption behaves; the pressure of the magma and the type of magma.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding the types of magma, this was asked and answered in the question, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/5267/is-the-magma-in-one-volcano-different-from-the-magma-in-every-other-volcano/5268#5268&quot;&gt;Is the magma in one volcano different from the magma in every other volcano?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With current volcanoes there are three types of magma: basaltic, andesitic and rhyolitic.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Basaltic magmas are hot, have low viscosity, low gas content and flow&#xA;relatively smoothly.&lt;/li&gt;&#xA;&lt;li&gt;Andesite magmas are mid temperature magmas that have moderate&#xA;viscosity and gas content and can be moderately explosive.&lt;/li&gt;&#xA;&lt;li&gt;Rhyolite magmas are lower temperature magmas with high viscosity and&#xA;high gas content and they erupt explosively.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;For magma to rise to the Earth's surface in a volcanic eruption it can only do so because of the pressure the magma is under. The higher the pressure, the more quickly the magma rises and the more energy it contains and the more explosive it can be.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other factor affecting the explosive nature of magmas is the gas content they contain. Deep underground, the gases are also under the same pressure as the magma. As the magma reaches the surface the gas within it decompresses causes the gases to expand. The expansion of the gases makes the magma explosive.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-01-19T03:50:08.953" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7295" PostTypeId="1" AcceptedAnswerId="12209" CreationDate="2016-01-19T14:00:39.133" Score="1" ViewCount="389" Body="&lt;p&gt;I was analyzing a dataset in which precipitation intensity(inches/hr) and the type of precipitation was given. For example:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;{precipIntensity:0.0029,pricpType:&quot;Rain&quot;}&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;I'm just curious how it can be predicted that it's raining in a particular area when the precipitation intensity is given ? Is there any formula or threshold by which we can predict the type of precipitation ?&lt;/p&gt;&#xA;" OwnerUserId="5065" LastActivityDate="2017-09-02T19:04:55.717" Title="How can we predict if it's raining, drizzling or there is snow fall by using precipitation intensity (inches/hour)?" Tags="|precipitation|rainfall|snow|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="7296" PostTypeId="1" CreationDate="2016-01-19T14:13:15.917" Score="6" ViewCount="2928" Body="&lt;p&gt;The projection for sea level rise due to global warming seem to hover about 1m by 2100, let's use this figure. How far upstream would this noticably affect a large river, e.g. the Rhine?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think it is obvious that the Delta would be changed severely, while it is nigh impossible to say accuratly how exactly (I assume). Upstream, I think the following effects com into play: Less hydraulic head means less flow velocity, more sedimentation and a higher water level in the river bed (the river needs more cross section to achieve the same volume flow with less head). Are these assumptions correct so far?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now the main question is how far upstream we would notice these changes in river behavior: Only at 1m above new sea level, or 10m, or 100m? Is this stronger determined by linear distance along the river, or by height above (new) sea level? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I prefer the Rhine as an example because it's the closest large river. If someone has a good answer for another large river I'm happy too.&lt;/p&gt;&#xA;" OwnerUserId="117" LastEditorUserId="725" LastEditDate="2016-01-22T10:39:50.547" LastActivityDate="2016-01-22T10:39:50.547" Title="How far upstream would severe sea level rise (1m) noticably affect a large river?" Tags="|climate-change|sea-level|sedimentology|rivers|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7297" PostTypeId="1" AcceptedAnswerId="7304" CreationDate="2016-01-19T14:15:13.090" Score="9" ViewCount="1507" Body="&lt;p&gt;I have read a paper discussing the concentration of air pollutants and their background concentration. In the paper &lt;a href=&quot;http://dx.doi.org/10.1016/j.atmosenv.2015.12.046&quot; rel=&quot;nofollow noreferrer&quot;&gt;Characterization of background air pollution exposure in urban environments using a metric based on Hidden Markov Models&lt;/a&gt;, Gómez-Losada et al wrote:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Urban area air pollution results from local air pollutants (from&#xA;  different sources) and horizontal transport (background pollution).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, does this mean that the background concentration of a specific area is the general effect of the emission and dispersion of the whole area? And how would one obtain the background concentration of air pollutants in a  specific area or point?&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="725" LastEditDate="2017-05-06T04:27:00.160" LastActivityDate="2017-05-06T04:27:00.160" Title="What's the background concentration of trace gas/pollutants?" Tags="|atmosphere|atmospheric-chemistry|air-pollution|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7299" PostTypeId="1" AcceptedAnswerId="7340" CreationDate="2016-01-19T15:57:44.077" Score="5" ViewCount="143" Body="&lt;p&gt;Are there any local environmental catastrophes that affected another places in the world? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a huge list of environmental disasters on Wikipedia that I have found: &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_environmental_disasters&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/List_of_environmental_disasters&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would really appreciate if there are some academic or non academic references that point out the global effects of local environmental disasters?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: To be more specific, for example, can a catastrophe that occurred in a Latin American country affect the environmental quality (pollution level) in another place in the world (Asia, Africa or another place)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's say that the pollution level increased in USA and resulted in a catastrophe. Could we say that higher level of pollution and catastrophe occurred in USA can cause another catastrophe in somewhere else?&lt;/p&gt;&#xA;" OwnerUserId="2827" LastEditorUserId="725" LastEditDate="2016-01-22T10:44:46.867" LastActivityDate="2016-01-22T11:00:25.743" Title="how are the global effects of local environmental disasters?" Tags="|volcanic-hazard|reference-request|seismic-hazards|natural-disasters|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7300" PostTypeId="1" AcceptedAnswerId="7301" CreationDate="2016-01-19T17:48:44.870" Score="2" ViewCount="421" Body="&lt;p&gt;What information does cloud fraction provide about weather on a certain day? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do low-level (1000-700 hPa) cloud fraction, optical thickness of all clouds and total cloud fraction provide any information about whether it rains or not?&lt;/p&gt;&#xA;" OwnerUserId="5122" LastEditorUserId="192" LastEditDate="2016-01-19T18:16:10.430" LastActivityDate="2016-01-19T18:16:10.430" Title="Does cloud fraction of 0 for low clouds means it was raining?" Tags="|meteorology|clouds|precipitation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7301" PostTypeId="2" ParentId="7300" CreationDate="2016-01-19T18:01:50.870" Score="3" Body="&lt;p&gt;Depending on context, cloud fraction can mean:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;the fraction of the visible sky covered by clouds (total cloud fraction).  This is what an observer from below or above sees and this is what is normally reported by measurements&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;the fraction of a particular area and altitude covered by clouds.  This is what is typically reported by models.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The differing definitions need to be kept in mind when comparing models to measurements.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Under normal circumstances, clouds are a necessary but not a sufficient requirement for precipitation (there are &lt;a href=&quot;https://en.wikipedia.org/wiki/Diamond_dust&quot; rel=&quot;nofollow&quot;&gt;some exceptions&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer your titular question: No, a cloud fraction of 0 for low clouds does &lt;em&gt;not&lt;/em&gt; mean it was raining.  Nor does it necessarily mean it was not raining.  Remember: a total cloud fraction of 0 means a clear sky, a total cloud fraction of 1 means a completely covered sky.  So a low level cloud fraction of 0 means there are &lt;em&gt;no&lt;/em&gt; low level clouds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer the question you ask in the content of your post: Statistically speaking, yes.  The quantities &lt;em&gt;low-level cloud fraction&lt;/em&gt;, &lt;em&gt;cloud optical thickness&lt;/em&gt;, and &lt;em&gt;total cloud fraction&lt;/em&gt; do contain information about precipitation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the total cloud fraction is zero, there is no precipitation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the cloud fraction for low clouds is zero, but for mid-level or high clouds is non-zero, it may or may not be raining.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cloud optical thickness should correlate with precipitation occurrence and intensity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, these quantities do not provide &lt;em&gt;complete&lt;/em&gt; information about precipitation.  You can't say with full certainty that a day is rainy based on these quantities alone — but you can say which days certainly aren't.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2016-01-19T18:07:29.980" LastActivityDate="2016-01-19T18:07:29.980" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7302" PostTypeId="1" AcceptedAnswerId="7303" CreationDate="2016-01-19T20:04:23.583" Score="3" ViewCount="891" Body="&lt;p&gt;I'm trying to read &lt;a href=&quot;http://navigator.eumetsat.int/discovery/Start/DirectSearch/DetailResult.do?f%28r0%29=EO:EUM:DAT:METOP:IASIL1C-ALL&quot; rel=&quot;nofollow noreferrer&quot;&gt;IASI GDS Level 1C&lt;/a&gt; data (all spectral samples) in the EUMETSAT EPS Native Format, as documented in the &lt;a href=&quot;http://www.eumetsat.int/website/wcm/idc/idcplg?IdcService=GET_FILE&amp;amp;dDocName=PDF_TEN_96167-EPS-GPFS&amp;amp;RevisionSelectionMethod=LatestReleased&amp;amp;Rendition=Web&quot; rel=&quot;nofollow noreferrer&quot;&gt;Generic Product Format Specification&lt;/a&gt; (PDF, 738 KB, 72 pages) and the &lt;a href=&quot;http://www.eumetsat.int/website/wcm/idc/idcplg?IdcService=GET_FILE&amp;amp;dDocName=PDF_IASI_LEVEL_1_PFS&amp;amp;RevisionSelectionMethod=LatestReleased&amp;amp;Rendition=Web&quot; rel=&quot;nofollow noreferrer&quot;&gt;IASI Level 1 Product Format Specification&lt;/a&gt; (PDF, 2.5 MB, 60 pages).  EUMETSAT supports a &lt;a href=&quot;http://www.eumetsat.int/website/home/Data/DataDelivery/SupportSoftwareandTools/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;reading routine in IDL&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://www.eumetsat.int/website/wcm/idc/idcplg?IdcService=GET_FILE&amp;amp;dDocName=PDF_IASI_LEVEL_1_PROD_GUIDE&amp;amp;RevisionSelectionMethod=LatestReleased&amp;amp;Rendition=Web&quot; rel=&quot;nofollow noreferrer&quot;&gt;IASI Level 1 Product Guide&lt;/a&gt; (PDF, 5.8 MB, 110 pages), section 5.1, notes that &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The products can be read using standard HDF libraries&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;but trying to open a test file with&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;code&gt;h5py.File('IASI_xxx_1C_M02_20110528114454Z_20110528132653Z_N_O_20110528132912Z.nat', 'r')&lt;/code&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;results in&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;code&gt;OSError: Unable to open file (Unable to find a valid file signature)&lt;/code&gt;,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and neither the Generic Product Format Specification nor the IASI Product Format Specification mention HDF, which would be odd if the format was HDF-compatible.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="725" LastEditDate="2017-05-06T04:25:25.160" LastActivityDate="2017-05-06T21:44:27.570" Title="How do I read IASI GDS L1C in Python?" Tags="|data-formats|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7303" PostTypeId="2" ParentId="7302" CreationDate="2016-01-19T20:04:23.583" Score="2" Body="&lt;p&gt;The &lt;a href=&quot;http://www.stcorp.nl/beat/&quot; rel=&quot;nofollow&quot;&gt;Basic ENVISAT Atmospheric Toolbox&lt;/a&gt; (BEAT) contains a component called the &lt;a href=&quot;http://stcorp.nl/coda/&quot; rel=&quot;nofollow&quot;&gt;Common Data Access toolbox&lt;/a&gt; (CODA; also available &lt;a href=&quot;https://github.com/stcorp/coda&quot; rel=&quot;nofollow&quot;&gt;on github&lt;/a&gt;).  BEAT and CODA are written in C and have bindings for Python (as well as Matlab, IDL, and a few other languages).  Among the &lt;a href=&quot;http://www.stcorp.nl/beat/documentation/beatl2-data/index.html&quot; rel=&quot;nofollow&quot;&gt;long list of supported products&lt;/a&gt; is IASI L1C.  Apparently, BEAT is going to be replaced by HARP (&lt;a href=&quot;https://github.com/stcorp/harp&quot; rel=&quot;nofollow&quot;&gt;github page&lt;/a&gt;), but HARP reportedly does not yet support IASI L1C.  BEAT, CODA, and HARP are all available under the GPL.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although the BEAT website reports Python bindings are only available for Python 2.7, I have successfully used CODA with Python 3.5 (I did not try BEAT as I do not currently need the higher-level functionality it offers).&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2016-01-20T14:35:50.493" LastActivityDate="2016-01-20T14:35:50.493" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7304" PostTypeId="2" ParentId="7297" CreationDate="2016-01-19T21:13:27.153" Score="6" Body="&lt;p&gt;&lt;a href=&quot;http://glossary.ametsoc.org/wiki/Background_pollution&quot; rel=&quot;nofollow&quot;&gt;Background pollution&lt;/a&gt; is what would be measured if no anthropogenic emissions existed.  In other words, if you shut off human activity (or avoid the emissions from it), you can measure the background.  Sometimes this is called the natural background.  There are also regional backgrounds, like &quot;the US background&quot;, which additionally includes anthropogenic sources from outside the region.  In order to measure background concentrations, you need to be in a remote area that is not influenced by human activity (e.g. see &quot;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0301479713005021&quot; rel=&quot;nofollow&quot;&gt;Influence of background particulate matter on urban air quality in the Pacific Northwest&lt;/a&gt;&quot; by Timonen et al., 2013).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Background concentrations of particulate matter can approach zero in pristine areas, but will be seasonally influenced by natural events like wildfires and dust storms.  Background NOx also approaches zero in pristine areas but can be perturbed by lightning generation and soil processes.  In contrast, background concentrations of ozone can rise naturally without an emissions source, especially in mountainous areas that are exposed to air from stratospheric intrusions.  Ozone is one of few the air pollutants whose background concentrations are significantly influenced by sources not at the surface.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using an air quality model, a researcher can &quot;zero-out&quot; anthropogenic emissions in order to estimate the background.  There are also source-apportionment techniques that can be used to estimate the background (see &quot;&lt;a href=&quot;http://adsabs.harvard.edu/abs/2015AtmEn.109..282D&quot; rel=&quot;nofollow&quot;&gt;Comparison of background ozone estimates over the western United States based on two separate model methodologies&lt;/a&gt;&quot; by Dolwick et al., 2015).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might enjoy &lt;a href=&quot;http://www3.epa.gov/ozonepollution/pdfs/whitepaper-bgo3-final.pdf&quot; rel=&quot;nofollow&quot;&gt;this white paper&lt;/a&gt; that the EPA recently released about the complexities involved with estimating background ozone. &lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2016-01-20T04:41:31.267" LastActivityDate="2016-01-20T04:41:31.267" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7306" PostTypeId="2" ParentId="7296" CreationDate="2016-01-19T22:38:25.343" Score="3" Body="&lt;p&gt;This is both a simple and complex answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The simple bit is that a 1m rise in sea level would impact the river to a point 1m higher than the current point (with a slight error margin dependent on flow rates etc)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rise itself over the next 85 years will not push back along the river (as Michael mentioned) as it's not like a tidal bore such as the &lt;a href=&quot;https://www.youtube.com/watch?v=IKA39LQOIck&quot; rel=&quot;nofollow&quot;&gt;Severn Bore&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The complex bit is that the 1m rise could be along an estuary, or across winding wetlands, or a wide delta or other feature, so the change to river flow could actually be quite catastrophic. And these effects could impact very far upstream, especially in the case of a river such as the Rhine, with a heavily populated floodplain. &lt;a href=&quot;https://en.wikipedia.org/wiki/Rhine&quot; rel=&quot;nofollow&quot;&gt;Wikipedia notes the last 50km of the Rhine are at 0m elevation&lt;/a&gt;, so that's an incredibly large possible impact area.&lt;/p&gt;&#xA;" OwnerUserId="755" LastActivityDate="2016-01-19T22:38:25.343" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7308" PostTypeId="2" ParentId="7283" CreationDate="2016-01-19T23:17:31.643" Score="46" Body="&lt;p&gt;Depends on your eye. You can realise the curvature of the Earth by just going to the beach. Last summer I was on a scientific cruise in the Mediterranean. I took two pictures of a distant boat, within an interval of a few seconds: one from the lowest deck of the ship (left image), the other one from our highest observation platform (about 16 m higher; picture on the right): &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OGsz0.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OGsz0.jpg&quot; alt=&quot;A distant boat seen from 6 m and 22 m above the sea surface&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;A distant boat seen from 6 m (left) and from 22 m (right) above the sea surface. This boat was about 30 km apart. My pictures, taken with a 30x optical zoom camera.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The part of the boat that is missing in the left image is hidden by the quasi-spherical shape of the Earth. In fact, if you would know the size of the boat and its distance, we could infer the radius of the Earth. But since we already know this, let's do it the other way around and deduce the distance to which we can see the full boat: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The distance $d$ from an observer $O$ at an elevation $h$ to the visible horizon follows the equation (adopting a spherical Earth):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;$$&#xA;d=R\times\arctan\left(\frac{\sqrt{2\times{R}\times{h}}}{R}\right)&#xA;$$&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;where $d$ and $h$ are in meters and $R=6370*10^3m$ is the radius of the Earth. The plot is like this: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/s7TA6.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/s7TA6.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Distance of visibility &lt;em&gt;d&lt;/em&gt; (vertical axis, in km), as a function of the elevation &lt;em&gt;h&lt;/em&gt; of the observer above the sea level (horizontal axis, in m).&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From just 3 m above the surface, you can see the horizon 6.2 km apart. If you are 30 m high, then you can see up to 20 km far away. This is one of the reasons why the ancient cultures, at least since the sixth century BC, knew that the Earth was curved, not flat. They just needed good eyes. You can read first-hand Pliny (1st century) on the unquestionable spherical shape of our planet in his &lt;em&gt;&lt;a href=&quot;http://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.02.0137%3Abook%3D2%3Achapter%3D2&quot; rel=&quot;noreferrer&quot;&gt;Historia Naturalis&lt;/a&gt;&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fNovp.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fNovp.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;strong&gt;Cartoon defining the variables used above. &lt;em&gt;d&lt;/em&gt; is the distance of visibility, &lt;em&gt;h&lt;/em&gt; is the elevation of the observer &lt;em&gt;O&lt;/em&gt; above the sea level.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But addressing more precisely the question. Realising that the horizon is lower than normal (lower than the perpendicular to gravity) means realising the angle ($gamma$) that the horizon lowers below the flat horizon (angle between $OH$ and the tangent to the circle at &lt;em&gt;O&lt;/em&gt;, see cartoon below; this is equivalent to gamma in that cartoon).  This angle depends on the altitude $h$ of the observer, following the equation:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;$$&#xA;\gamma=\frac{180}{\pi}\times\arctan\left(\frac{\sqrt{2\times{R}\times{h}}}{R}\right)&#xA;$$&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;where &lt;em&gt;gamma&lt;/em&gt; is in degrees, see the cartoon below. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This results in this dependence between &lt;em&gt;gamma&lt;/em&gt; (vertical axis) and &lt;em&gt;h&lt;/em&gt; (horizontal axis):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/nooxN.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nooxN.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Angle of the horizon below the flat-Earth horizon (&lt;em&gt;gamma&lt;/em&gt;, in degrees, on the vertical axis of this plot) as a function of the observer's elevation &lt;em&gt;h&lt;/em&gt; above the surface (meters). Note that the apparent angular size of the Sun or the Moon is around 0.5 degrees.&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, at an altitude of only 290 m above the sea level you can already see 60 km far and the horizon will be lower than normal by the same angular size of the sun (half a degree). While normally we are no capable of feeling this small lowering of the horizon, there is a cheap telescopic device called levelmeter that allows you to point in the direction perpendicular to gravity, revealing how lowered is the horizon when you are only a few meters high. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you are on a plane ca. 10,000 m above the sea level, you see the horizon 3.2 degrees below the astronomical horizon (O-H), this is, around 6 times the angular size of the Sun or the Moon. And you can see (under ideal meteorological conditions) to a distance of 357 km. &lt;strong&gt;Felix Baumgartner&lt;/strong&gt; roughly doubled this number but the pictures circulated in the news were taken with very wide angle, so the ostensible curvature of the Earth they suggest is mostly an &lt;strong&gt;artifact&lt;/strong&gt; of the camera, not what Felix actually saw. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/liWSt.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/liWSt.jpg&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;This ostensible curvature of the Earth is mostly an artifact of the camera's wide-angle objective, not what Felix Baumgartner actually saw.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="1379" LastEditorUserId="1379" LastEditDate="2017-11-13T17:08:25.023" LastActivityDate="2017-11-13T17:08:25.023" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="7309" PostTypeId="2" ParentId="7299" CreationDate="2016-01-20T02:25:15.073" Score="5" Body="&lt;p&gt;An excellent example of this would be the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Pinatubo#1991_eruption&quot;&gt;Mount Pinatubo&lt;/a&gt; eruption in 1991. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Plinian_eruption&quot;&gt;specific nature&lt;/a&gt; of this eruption features massive amounts of aerosols and ash put into the atmosphere. When Mount Pinatubo erupted, the amount of dust and ash it injected into the atmosphere was responsible for a worldwide reduction in temperature of 0.5–0.6 °C in the northern hemisphere over the next year, as well as a massive increase in ozone depletion.&lt;/p&gt;&#xA;" OwnerUserId="496" LastActivityDate="2016-01-20T02:25:15.073" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7310" PostTypeId="1" AcceptedAnswerId="7359" CreationDate="2016-01-20T09:31:39.773" Score="10" ViewCount="314" Body="&lt;p&gt;I'm working on a project aiming at finding some potential point as a new air pollutant monitor site for a city to measure $SO_2$, $NO_2$, $PM_{2.5}$, etc.&lt;br&gt;&#xA;After modeling the surface concentration of the area, here is my select standard:   &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The violation situation    &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Finding the area which exceed the local air quality standard most in the modeling area.          &lt;/p&gt;&#xA;&lt;/blockquote&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The representation area       &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Each modeling grid concentration is a time-series dataframe. Compute the&lt;br&gt;&#xA;  spatial correlation coefficient (r) between one grid with surroundings area,&lt;br&gt;&#xA;  we can get each grid's represent area assuming there is a cut-off coefficient $r_c$.       &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;For example, 3 grid i, j, k in the city.&lt;/em&gt;&lt;br&gt;&#xA;&lt;em&gt;$r_(ij) &amp;gt; r_c$ → $grid_i$ can represent the  temporal variation of   $grid_j$&lt;/em&gt;&lt;br&gt;&#xA;&lt;em&gt;$r_(ik) &amp;lt; r_c$ → $grid_i$ can't represent the  temporal variation of $grid_k$&lt;/em&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Population density   &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Considering the environmental exposure healthy risks, I add the pop-ind data for each concentration grid&lt;/p&gt;&#xA;&lt;/blockquote&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;h3&gt;Here is my question&lt;/h3&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Are these principle enough for a monitoring site?   &lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;How to combine the results from the analysis based on multi-air pollutant data?&lt;br&gt;&#xA;( In practice, one monitoring site often measure various air pollutants simultaneously, but my method is based on a specific type of air pollutant owing to the different emission source &amp;amp; chemical  reactivity) &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Combining each site, We can get a monitoring network, how to estimate the network's strengths and weaknesses?    &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="5214" LastEditDate="2018-09-20T02:50:47.963" LastActivityDate="2018-09-20T02:50:47.963" Title="What principles do we consider when selecting an air pollution monitor location?" Tags="|atmosphere|measurements|atmosphere-modelling|atmospheric-chemistry|air-pollution|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="7311" PostTypeId="1" CreationDate="2016-01-20T11:27:27.773" Score="1" ViewCount="73" Body="&lt;p&gt;I saw some indexes about environmental quality in many websites, like in:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.numbeo.com/pollution/rankings_by_country.jsp&quot; rel=&quot;nofollow&quot;&gt;http://www.numbeo.com/pollution/rankings_by_country.jsp&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I wonder why the environmental quality index is higher in USA and in Europe than in other sub-Saharan or Latin American countries. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We know that approximately 1/3 of the world total pollution is coming from USA and Europe. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems to me a little bit strange. Are there any features about the circulation of CO&lt;sub&gt;2&lt;/sub&gt; on atmosphere that could explain this fact? Or are there just economic reasons that concern development levels of countries?&lt;/p&gt;&#xA;" OwnerUserId="2827" LastEditorUserId="725" LastEditDate="2016-01-22T10:42:22.883" LastActivityDate="2016-01-22T10:42:22.883" Title="Why is the environmental quality index high in USA, the second most polluting country?" Tags="|air-pollution|" AnswerCount="1" CommentCount="3" ClosedDate="2016-01-24T18:02:44.800" ContentLicense="CC BY-SA 3.0" />
  <row Id="7312" PostTypeId="2" ParentId="7311" CreationDate="2016-01-20T12:24:33.770" Score="1" Body="&lt;p&gt;The website you cited has this &lt;a href=&quot;http://www.numbeo.com/pollution/indices_explained.jsp&quot; rel=&quot;nofollow&quot;&gt;explanation&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Most of our data are based on perceptions (opinions) from visitors of this website. For pollution section, we include some relevant data from World Health Organization and other institutions if we find it helpful.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So basically that index is based on people's perception, and CO2 pollution (which your &quot;1/3 of the world total pollution&quot; is probably based on) is not something that people can see or smell, it's problematic because of indirect effects. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The USA and Europe have pretty strict regulation to reduce the more perceptible components of vehicle and industry exhausts, like soot, sulfur oxides and nitrogen oxides. Their cities also often have good public transportation and zoning laws that separate industry and residential areas.&lt;/p&gt;&#xA;" OwnerUserId="1153" LastActivityDate="2016-01-20T12:24:33.770" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7313" PostTypeId="2" ParentId="7296" CreationDate="2016-01-20T14:26:55.217" Score="1" Body="&lt;p&gt;It seems that your indications regarding changing conditions following sea level rise are valid. Rising base level will move the current depositional processes inland some distance as you have indicated. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The process will apply basically in the same way to all rivers that terminate in a body of water that will be affected by sea level rise, for example rivers that terminate in a lake that will not rise due to the changing climate will not be affected. There are some circumstances where lakes in steep terrain could be affected by increased meltwater from surrounding glaciers, and that increase could be significant, but the models predicting sea level rise are not referring to particular local conditions, which are on a case by case basis, but possibly very important to the local populations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where the process becomes interesting is what happens to a particular river, because they will all be different. In order to determine what will likely happen, one must consider the physical aspects of the river, what is the change in elevation near the terminus, what is the topography of the floodplain, how much does the river meander as it approaches the terminus? These and other similar factors will determine what happens as the base level rises. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you consider a river that has very little change in elevation, and meanders across a wide floodplain, the amount of inundation caused by a one meter rise in base level will cover a large area of what is now floodplain and likely intermittently wet or dry based on seasonal fluctuations. Compare this with a river that occupies a canyon, or is deeply incised and has a steep gradient to the base level, the base level will rise within those constraining features and little will likely happen to the narrow floodplain that has been present. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;First step for your inquiry about the Rhine River is to look at the topography surrounding the river, and mark out a one meter change in the area surrounding the river beginning from the terminus, as the terrain becomes steeper toward the head water the change from current condition will diminish. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Direct answer to your question is that the inland affect of one meter of base level rise could reach much farther than one meter upstream depending on the topographical features near the river terminus, and each river will be different.&lt;/p&gt;&#xA;" OwnerUserId="5097" LastActivityDate="2016-01-20T14:26:55.217" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7314" PostTypeId="2" ParentId="35" CreationDate="2016-01-20T19:27:56.937" Score="5" Body="&lt;p&gt;Big question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is not enough data resolution at the moment, neither spatially nor temporally. There are geological periods thought to have undergone higher erosion rates based on the abundance of some sediment facies, such as during the Trias. There are also many sedimentary basins where where the evolution of sedimentation rates is well known. But this depends strongly on local geographic/tectonic conditions, such as the available accommodation space of the tectonic subsidence, so it gives no information on what is going on at global scale. To make it even more difficult, there are good indications that we are biased in the ways we measure both &lt;a href=&quot;http://www.nature.com/nature/journal/v505/n7483/full/505294a.html&quot; rel=&quot;nofollow&quot;&gt;erosion&lt;/a&gt; and &lt;a href=&quot;http://clasticdetritus.com/2010/06/28/using-sedimentation-rates-to-infer-long-term-global-climate-change/&quot; rel=&quot;nofollow&quot;&gt;sedimentation&lt;/a&gt;, exaggerating recent transport rates relative to longer term. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To have the global perspective you want, geoscientists need a coherent, world-wide, statistically representative set of past erosion or sedimentation measures, and that for each geological period. But erosion and sedimentation take years to be determined for a particular basin/orogen setting and for a specific period; the gaps are enormous. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only roughly quantified period at a global scale is the Miocene-Pliocene-Quaternary. And even there the discussion is very open. The following studies suggest that &lt;strong&gt;global erosion/sedimentation rates have increased during the last 4-6 million years&lt;/strong&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first is based on a compilation of delta sedimentation rates:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Zhang, P., Molnar, P.&amp;amp; Downs, W. R. Increased sedimentation rates and&#xA;  grain sizes 2–4 Myr ago due to the influence of climate change on&#xA;  erosion rates. Nature 410, 891–897 (2001).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The second uses thermochronology, mostly Apatite Fission Track analyses: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Herman F, Seward D, Valla PG, Carter A, Kohn B,Willett SD, Ehlers TA.&#xA;  2014. Worldwide acceleration of mountain erosion under a cooling climate. Nature 504: 423–426. DOI: 10.1038/nature12877&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Both interpret the acceleration of erosion as a result of the changes in Earth's climate during that period: initiation of the glacial interglacial cycle in the northern hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Due to the gaps in the geological outcrop record, and to our limited capacity of dating sediments, my bet is that it will take decades at least to have a reliable graph like the one you aim at. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this helps.&lt;/p&gt;&#xA;" OwnerUserId="1379" LastEditorUserId="1379" LastEditDate="2016-01-22T16:41:09.780" LastActivityDate="2016-01-22T16:41:09.780" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7315" PostTypeId="1" AcceptedAnswerId="7320" CreationDate="2016-01-20T20:21:42.870" Score="3" ViewCount="1156" Body="&lt;p&gt;I'm curious to know where commercial weather services like the Weather Channel and Weather Underground get their wind speed and direction measurements, to produce maps like this one (&lt;a href=&quot;http://www.wunderground.com/maps/us/WindSpeed.html?MR=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.wunderground.com/maps/us/WindSpeed.html?MR=1&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Az1Gg.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Az1Gg.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A model is probably used, but how does the station measure or acquire real measurements to assimilate the data into the model? Is it by regularly placed anemometers on the ground? Or data measured by satellites?&lt;/p&gt;&#xA;" OwnerUserId="2645" LastEditorUserId="2645" LastEditDate="2016-01-20T21:27:08.083" LastActivityDate="2016-01-20T23:44:38.857" Title="How do weather services measure wind" Tags="|meteorology|wind|remote-sensing|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7316" PostTypeId="1" CreationDate="2016-01-20T21:49:47.917" Score="24" ViewCount="6519" Body="&lt;p&gt;&lt;a href=&quot;https://www.washingtonpost.com/news/energy-environment/wp/2016/01/20/its-official-2015-smashed-2014s-global-temperature-record-it-wasnt-even-close/&quot; rel=&quot;nofollow noreferrer&quot;&gt;2015&lt;/a&gt; is the hottest year on record, and the average temperature continues to rise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't understand why this continues, as (over the past twenty years) &lt;em&gt;so&lt;/em&gt; much work was put into reducing Global Warming over the past 40 years, yet not only does the temperature not fall, it continues to rise &lt;em&gt;more than it did between 1870-1960&lt;/em&gt;. &lt;a href=&quot;https://i.stack.imgur.com/jQm86.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jQm86.gif&quot; alt=&quot;http://www.bbc.co.uk/schools/gcsebitesize/geography/climate_change/describing_climatic_trends_rev1.shtml&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't understand something. The amount of industry &lt;em&gt;went through the roof (literally) between 1870 to 1960, and no one cared about the environment&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now that we do care about it, and (at least somewhat) legislate cleaner cars, factories, etc, I would expect the temperature to even out, yet it doesn't&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why not?&lt;/p&gt;&#xA;" OwnerUserId="5233" LastEditorUserId="543" LastEditDate="2018-01-13T03:54:49.033" LastActivityDate="2018-01-13T03:54:49.033" Title="Why is the temperature *still* rising?" Tags="|atmosphere|climate-change|climate|" AnswerCount="4" CommentCount="17" ContentLicense="CC BY-SA 3.0" />
  <row Id="7317" PostTypeId="2" ParentId="7316" CreationDate="2016-01-20T22:22:13.483" Score="23" Body="&lt;p&gt;Your premises are flawed due to the lack of two critical details:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Population rise; the sheer number of people on the planet that are consuming resources has risen to 7 billion people.  &lt;/li&gt;&#xA;&lt;li&gt;Standard of Living; a greater percentage of people in the world live a &quot;Western&quot; style, which consumes more goods per capita.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;You should study something like the &lt;a href=&quot;http://www.globalcarbonproject.org/&quot;&gt;Global Carbon Project&lt;/a&gt; to gain a greater perspective on carbon and climate.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NO2MX.png&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NO2MX.png&quot; alt=&quot;Global Carbon Budget&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="725" LastEditDate="2016-01-21T00:55:44.077" LastActivityDate="2016-01-21T00:55:44.077" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7318" PostTypeId="2" ParentId="7292" CreationDate="2016-01-20T22:51:33.113" Score="7" Body="&lt;p&gt;I will be using for an example in this answer the collapse of the lava dome at Mount St Helens in 1980. The lava dome on top of the mountain grew between March 20 and May 18, and then a landslide caused by the angle of the top of the dome exceeding the angle of repose of the country rock caused the pressure on the magma chamber underneath to be released, causing it to instantly boil and explode. Your suggestion to relieve pressure by either drilling or bombing would have had the same effect. Drilling or bombing a hole in this dome would have caused the pressure to greatly reduce, making all of the dissolved gases in the chamber to exsolve out, causing the pressure to instantly greatly increase, over what the surrounding rock was capable of containing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So by bombing or drilling a magma chamber that might be about to explode, you run the very real risk of guaranteeing that it will explode. The precursors earthquakes to the Mount St Helens eruption would have been the signal that something was wrong you would use to justify this intervention, and as a result you would have simply advanced the timetable of eruption. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good analogy is that of a radiator cap on a hot car engine. The coolant inside the radiator might be sitting at 20 or 30°C over its boiling temperature, but because it is under higher pressure due to the heat and being pumped around, it has not boiled. Once that pressure is relieved, it will instantly boil out of the radiator because of the reduction in pressure.&lt;/p&gt;&#xA;" OwnerUserId="496" LastEditorUserId="496" LastEditDate="2016-01-20T22:59:02.217" LastActivityDate="2016-01-20T22:59:02.217" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7319" PostTypeId="2" ParentId="7316" CreationDate="2016-01-20T23:29:26.517" Score="35" Body="&lt;p&gt;&quot;So much work&quot;? Actually, compared to the global rate of greenhouse gas emissions, it's a case of &quot;so &lt;em&gt;little&lt;/em&gt; work&quot;! From a scientific perspective the 'economists' solution' of carbon trading was always unlikely to achieve the required carbon cuts, as has been verified by their ineffectiveness over the last decade or so. As farrenthorpe points out, the rate of increase of CO&lt;sub&gt;2&lt;/sub&gt; is largely population-driven, and hence there is still an inexorable rise in mean atmospheric CO&lt;sub&gt;2&lt;/sub&gt;. The acid test of human efforts to limit global warming is whether the Hawaiian CO&lt;sub&gt;2&lt;/sub&gt; monitoring graph is flattening off:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/79DZD.png&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/79DZD.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It clearly isn't going to flatten anytime soon. In fact, if anything, it is getting steeper. So all the hot air from 'Paris', and previous talkfests, is evidently too little, too late. Realistically, limiting the average temperature rise to less than 2 °C, is now effectively unattainable. We have yet to see what 'all this work' can achieve. So far, almost nothing. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="725" LastEditDate="2016-01-21T08:57:00.577" LastActivityDate="2016-01-21T08:57:00.577" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="7320" PostTypeId="2" ParentId="7315" CreationDate="2016-01-20T23:44:38.857" Score="8" Body="&lt;p&gt;Weather stations and airports around the world almost always include an anemometer. Because of ground friction, the wind speed varies with height, so instrumental deployment is set at a standard height of 10 metres in open rural areas. This may require some adjustment in urban or forested areas. In fact, measuring accurate wind speeds above tree canopies is particularly difficult. There is quite an art in correctly positioning the instrumentation.&#xA;Thousands of such anemometers and direction sensors are deployed on nearly every continent, and the results are part of the routine reporting. Such reporting may be every 24, 12, or 6 hours, or even shorter periods down to and including 'continuous'. Then comes the number crunching, in which the strength and direction is gridded and plotted on what appears to be a uniform distribution of points. In reality it is very far from a uniform distribution.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With the introduction of increasing numbers of wind farms higher elevation wind measurements are becoming more important. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-01-20T23:44:38.857" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7321" PostTypeId="2" ParentId="4561" CreationDate="2016-01-21T07:46:16.087" Score="4" Body="&lt;p&gt;Writing about the San Francisco Bay salt ponds, &lt;a href=&quot;http://chemconnections.org/general/chem120/solutions-mixes.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dr R. J. Rusay notes&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Due to variable algal concentrations, vivid colors, from pale green to bright red are created. The color indicates the salinity of the ponds.  Micro-organisms change their hues as the salinity of the pond increases.  In low to mid-salinity ponds, green algae are predominant. In middle to high salinity ponds, an algae called Dunaliella salina shifts the color to red. Millions of tiny brine shrimp create an orange cast in mid-salinity ponds. Other bacteria such as Stichococcus also contribute tints.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Rusay says nothing about the Saloum Delta, but the explanation could be similar there.&lt;/p&gt;&#xA;" OwnerUserId="5076" LastEditorUserId="94" LastEditDate="2017-01-05T08:55:54.603" LastActivityDate="2017-01-05T08:55:54.603" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7322" PostTypeId="2" ParentId="7316" CreationDate="2016-01-21T08:20:58.713" Score="10" Body="&lt;p&gt;In addition to other answers:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;the oceans have been acting as a sort of heat capacitor, according to &lt;a href=&quot;http://www.climatehotmap.org/global-warming-effects/ocean-temperature.html&quot;&gt;climatehotmap.org&lt;/a&gt; the oceans took 20 times more heat than the atmosphere, this will increase the global warming over the next decade due to heat being discharged from the ocean&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.pri.org/stories/2015-06-24/thawing-permafrost-could-have-catastrophic-consequences-scientists-warn&quot;&gt;rising temperatures melt the permafrost&lt;/a&gt; which releases methane, an even more potent greenhouse gas than CO&lt;sub&gt;2&lt;/sub&gt; which results in a sort of &quot;permafrost carbon feedback loop&quot; where rising temperatures release more gasses leading to more rising temperatures&lt;/li&gt;&#xA;&lt;li&gt;sea level rise and shrinking polar caps increase the total amount of Earth's dark surfaces resulting in less energy being reflected back into space, meaning more heat on Earth, &lt;a href=&quot;http://www.greenfacts.org/en/arctic-climate-change/index.htm#3&quot;&gt;greenfacts.org&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;So, basically, there's a couple of hypothesized feedback loops that start happening when the planet heats up which in turn make the planet heat up more, see the &lt;a href=&quot;https://en.wikipedia.org/wiki/Runaway_climate_change&quot;&gt;Wikipedia article&lt;/a&gt; for more information,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;according to some sources we are either rapidly approaching (or maybe even there) on the point of no return when the positive feedback loops result in a greenhouse effect that will continue to grow even if all fossil fuel burning would come to an end in one day (&lt;a href=&quot;http://www.scientificamerican.com/article/have-we-passed-the-point-of-no-return-on-climate-change/&quot;&gt;Scientific American&lt;/a&gt;, &lt;a href=&quot;http://climate.nasa.gov/400ppmquotes/&quot;&gt;NASA&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Runaway_climate_change#Current_risk&quot;&gt;a bunch of resources on Wikipedia&lt;/a&gt; including &lt;a href=&quot;https://en.wikipedia.org/wiki/IPCC_Fourth_Assessment_Report&quot;&gt;UN&lt;/a&gt; and :cough: &lt;a href=&quot;https://www.reddit.com/r/IAmA/comments/3gvy5e/we_are_the_people_behind_the_point_of_no_return/&quot;&gt;Rolling Stone&lt;/a&gt; :cough: and others...)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's actually a &lt;a href=&quot;http://m.space.com/29831-water-escapes-a-warm-planet-will-earth-become-like-mars.html&quot;&gt;growing body of evidence&lt;/a&gt; that water worlds are rare and fragile due to the aforementioned feedback loops and that we might be capable of turning Earth into a kind of hot hell similar to Venus by causing an unstoppable chain reaction.&lt;/p&gt;&#xA;" OwnerUserId="5237" LastEditorUserId="5237" LastEditDate="2016-01-21T11:07:09.280" LastActivityDate="2016-01-21T11:07:09.280" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7323" PostTypeId="2" ParentId="7292" CreationDate="2016-01-21T09:16:55.197" Score="2" Body="&lt;p&gt;Yes, but no.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It highly depends on the circumstances. As Fred said in his answer, there are several types of magma. Some might flow almost like water while others might fragment and explode. You really want to know what kind of magma is inside the magma chamber before you release it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A possible thing to do, for example in Hawaii, is to force the magma to flow to the ocean or to a place where it will not flow over things we care about (houses, roads, people, etc). This might not always be possible, based on geometrical and topographical constraints. In areas where the magma is explosive, this might actually be a bad idea. It might not even work - I asked a friend of mine who deals with this kind of stuff and he said that if the hole is not wide enough (= at least several metres) magma will just flow in, solidify and plug the hole. Drill holes are usually centimetres wide, not metres. If you want to blow it up, you need quite a lot of stuff because this stuff might be deep: digging a hole severel metres wide 10s of metres deep is not something that's easy to do.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another problem is that you don't always know what kind of magma is there. You can have a guess, you can estimate it based on geophysical techniques, but sometimes you just don't know until it erupts. Even if you do, we still don't entirely understand the physics of how and why volcanos erupt. This is an active area of research and you don't want to do something that's potentially hazardous without understanding how it works.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-01-21T09:16:55.197" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7324" PostTypeId="2" ParentId="7281" CreationDate="2016-01-21T11:02:42.113" Score="4" Body="&lt;p&gt;The Moon's orbit is elliptical, not circular, and the maximum and minimum distance from the Moon to the center of the Earth (apogee and perigee, 405,385 and 363,630 km respectively) are much larger than the radius of the Earth (6370 km). Therefore, the distance you are asking for is very variable and it does not depend so much on the position of the Moon relative to the observer's horizon, but mainly on the position of the Moon along its own orbit. &lt;/p&gt;&#xA;" OwnerUserId="1379" LastActivityDate="2016-01-21T11:02:42.113" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7327" PostTypeId="1" AcceptedAnswerId="7333" CreationDate="2016-01-21T16:11:37.800" Score="8" ViewCount="5645" Body="&lt;p&gt;I'm wondering how to quote a Landsat mission product. I have seen many ways, but I can't decide which one is the best. Thus, I would like to know if there is a standard for the minimum information that should be quoted such as mission, data, sensor, orbita/ponto. Furthermore, do I have to include a link to access the image?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If anyone has any tips or guess on the subject would be grateful!&lt;/p&gt;&#xA;" OwnerUserId="5250" LastEditorUserId="5594" LastEditDate="2017-12-13T21:58:08.523" LastActivityDate="2020-09-14T18:53:24.643" Title="How to cite LandSat 8?" Tags="|geography|reference-request|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7328" PostTypeId="1" CreationDate="2016-01-21T16:44:11.227" Score="11" ViewCount="2631" Body="&lt;p&gt;How can I plot the wind direction in 3D, using the 3 wind vectors &lt;code&gt;u&lt;/code&gt;, &lt;code&gt;v&lt;/code&gt; and &lt;code&gt;w&lt;/code&gt;?&#xA;Normally, I create &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Wind_rose_plot.jpg&quot; rel=&quot;nofollow&quot;&gt;2D wind rose plots in the traditional way&lt;/a&gt;, using R or MATLAB. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which ways do you know for plotting this in 3D, using the additional &lt;code&gt;w&lt;/code&gt; vector?&lt;br /&gt;Do you have code examples or tips for packages?&lt;/p&gt;&#xA;" OwnerUserId="4784" LastEditorUserId="595" LastEditDate="2016-10-17T09:35:05.797" LastActivityDate="2017-03-18T12:43:18.950" Title="Plotting the wind direction in 3D?" Tags="|wind|visualization|" AnswerCount="4" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="7329" PostTypeId="1" CreationDate="2016-01-21T17:04:49.910" Score="-6" ViewCount="376" Body="&lt;p&gt;During the warm period before the most recent ice age, 120,000 years ago, roughly half of the Greenland ice sheet melted.This is thought to have been the cause of the last ice age.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question: If this occurred 120,000 years ago without human&#xA;   intervention what caused Greenland's glacial melting?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would appreciate Reading the credible provided links before &lt;strong&gt;voting, commenting or answering:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.arctic.noaa.gov/reportcard/greenland_ice_sheet.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;www.arctic.noaa.gov/reportcard/greenland_ice_sheet.html&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.wunderground.com/climate/greenland.asp?MR=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;www.wunderground.com/climate/greenland.asp?MR=1&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="4617" LastEditorUserId="5594" LastEditDate="2017-12-13T21:57:08.330" LastActivityDate="2017-12-13T21:57:08.330" Title="Next Ice age may be unavoidable" Tags="|meteorology|geophysics|climate|climate-change|ice-age|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="7330" PostTypeId="1" AcceptedAnswerId="7349" CreationDate="2016-01-21T19:28:33.897" Score="7" ViewCount="3000" Body="&lt;p&gt;Can some one suggest me a web site for archived hourly wind data for Germany.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have seen &lt;a href=&quot;https://earthscience.stackexchange.com/questions/6740/website-that-contains-the-maps-of-atmospheric-pressure-and-wind-speeds&quot;&gt;here&lt;/a&gt; but it was not useful for me.&lt;/p&gt;&#xA;" OwnerUserId="5122" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-07-12T18:17:48.963" Title="Where can I get archived hourly wind speed data for Germany?" Tags="|meteorology|wind|open-data|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7331" PostTypeId="2" ParentId="7330" CreationDate="2016-01-21T19:34:25.617" Score="7" Body="&lt;p&gt;The &lt;a href=&quot;http://gmao.gsfc.nasa.gov/research/merra/&quot; rel=&quot;nofollow noreferrer&quot;&gt;MERRA&lt;/a&gt; dataset has data for the world from 1979 to date. It updates frequently.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can get the data as HDF or NETCDF. If your GIS package doesn't read those, there will be translation packages around the web to convert them into a suitable format.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You'll want the U- and V- wind data. You might want pressure too. And possibly even turbulence data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you're interested in using this for simulating wind generation, then I highly recommend &lt;a href=&quot;http://www.met.reading.ac.uk/~energymet/data/Cannon2015/&quot; rel=&quot;nofollow noreferrer&quot;&gt;the paper by Cannon et al on analysing the MERRA data for wind energy simulation&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might also be interested in the &lt;a href=&quot;http://cfs.ncep.noaa.gov/cfsr/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CFSR&lt;/a&gt; data, which runs 1979-2010: in connection with using this paper for wind energy simulation, see &lt;a href=&quot;http://dx.doi.org/10.1016/j.renene.2014.12.025&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt; by Sharp et al.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;https://opendata.stackexchange.com/a/5602/530&quot;&gt;I've previously posted this elsewhere on StackExchange&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="-1" LastEditDate="2017-04-13T12:57:29.940" LastActivityDate="2016-01-21T19:34:25.617" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7332" PostTypeId="1" AcceptedAnswerId="7337" CreationDate="2016-01-21T19:37:27.127" Score="18" ViewCount="3759" Body="&lt;p&gt;The velocity of p-waves emanating from earthquakes is in the range of 5-8 km/s (&lt;a href=&quot;https://en.wikipedia.org/wiki/P-wave&quot;&gt;link&lt;/a&gt;)--let's assume it is 5 km/s. The earthquake depth is up to hundreds of kms deep underground (&lt;a href=&quot;http://www.usgs.gov/faq/categories/9827/3344&quot;&gt;link&lt;/a&gt;)--let's assume it is 100 km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, if a seismic station is installed at a depth of 50 km, and there are many of them in any given metropolitan area, then we can have a warning that is tens of seconds before the earthquake reaches the surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;While I realize that drilling down to 50 kn is no easy task, I would have imagined that saving human life is well worth the efforts. Why hasn't this been done so far? Is it that such a short notice (10s of seconds) isn't worth it?&lt;/p&gt;&#xA;" OwnerUserId="5254" LastEditorUserId="725" LastEditDate="2016-01-22T00:51:54.637" LastActivityDate="2017-06-27T14:49:29.350" Title="Why aren't seismic stations installed very deep underground so as to pre-warn from earthquakes?" Tags="|seismology|earthquakes|seismic-hazards|drilling|" AnswerCount="5" CommentCount="10" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7333" PostTypeId="2" ParentId="7327" CreationDate="2016-01-21T19:39:15.270" Score="6" Body="&lt;p&gt;Landsat products obtained via various sources (ex the EROS Center) can have their own requirements when using their products. For instance the &lt;a href=&quot;https://www.usgs.gov/centers/eros/data-citation&quot; rel=&quot;nofollow noreferrer&quot;&gt;EROS Data Citation page&lt;/a&gt; indicate that they are quite open regarding how their documents are cited and require the following acknowledgement only. For example&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Acknowledgement:&lt;/p&gt;&#xA;&lt;p&gt;Data available from the U.S. Geological Survey.&lt;/p&gt;&#xA;&lt;p&gt;See USGS Visual Identity System Guidance (link is external) for further details.&lt;/p&gt;&#xA;&lt;p&gt;Questions concerning the use or redistribution of USGS data should be directed to: ask@usgs.gov (link sends e-mail) or 1-888-ASK-USGS (1-888-275-8747).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Metadata files attached to images are often filled with useful information. Usual relevant information for a technical or scientific paper are the moment of acquisition, the scale, the bands, the name of the sensor, maybe the series of the product, maybe there is a serial number too, possibly a URL.&lt;/p&gt;&#xA;&lt;p&gt;I have cited in a recent paper the following for Landsat 7, and did not went into much details because it was a reworked product (a special issued mosaic), which was convenient for our scope:&lt;/p&gt;&#xA;&lt;p&gt;NRCan, Canada Centre for Remote Sensing. A complete orthorectified Landsat-7 mosaic&#xA;of the Canadian Arctic archipelago, August 2010. URL &lt;a href=&quot;http://geogratis.gc.ca/api/en/nrcan-rncan/ess-sst/-/(urn:iso:series)a-complete-orthorectified-landsat-7-mosaic-of-the-canadian-arctic-archipelago&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://geogratis.gc.ca/api/en/nrcan-rncan/ess-sst/-/(urn:iso:series)a-complete-orthorectified-landsat-7-mosaic-of-the-canadian-arctic-archipelago&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1411" LastEditorUserId="-1" LastEditDate="2020-09-14T18:53:24.643" LastActivityDate="2020-09-14T18:53:24.643" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="7334" PostTypeId="2" ParentId="7332" CreationDate="2016-01-21T22:39:31.233" Score="3" Body="&lt;p&gt;I think you've answered your own question when you ask if 10 seconds is too short notice and is it worth it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A question for you, what can anyone do in 10 seconds and how far can anyone travel in 10 seconds?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only way to possibly save lives when an earthquake is about to occur for people to move away from the earthquake site to a safe area. As you state earthquakes travel at 5 to 8 kilometres per second. Most people might be able to walk 5 to 8 kilometres per hour.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;People are not going to be able to get far in 10 seconds. Most people won't even be able to get out of the building they would be in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is nothing to be gained by having 10 seconds of warning prior to a major natural disastrous event.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-01-21T22:39:31.233" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7335" PostTypeId="2" ParentId="7332" CreationDate="2016-01-21T23:11:08.013" Score="8" Body="&lt;p&gt;I can see two major benefits of having a 10 second warning time:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;shutting down gas lines to prevent uncontrollable ruptures and fires after the tremor when comms channels are either destroyed or overloaded;&lt;/li&gt;&#xA;&lt;li&gt;giving people inside buildings time to hide in relatively more survivable spots before the building collapses. Duck and cover, reenacted against earthquakes.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;With this in mind, it's still a question of cost-benefit analysis and politics. Deep boreholes are costly; it took &lt;a href=&quot;http://www.earthscope.org/information/faqs&quot; rel=&quot;nofollow&quot;&gt;almost $200M&lt;/a&gt; to set up EarthScope &lt;a href=&quot;https://en.wikipedia.org/wiki/San_Andreas_Fault_Observatory_at_Depth&quot; rel=&quot;nofollow&quot;&gt;with two boreholes at San Andreas&lt;/a&gt;, the deeper one going down 1.67 miles. Evacuation benefits really start to accrue when you can get people outside rubble islands, and it isn't 10 seconds, more like 90 seconds upwards.&lt;/p&gt;&#xA;" OwnerUserId="269" LastEditorUserId="269" LastEditDate="2016-01-24T10:53:00.793" LastActivityDate="2016-01-24T10:53:00.793" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7336" PostTypeId="2" ParentId="7332" CreationDate="2016-01-22T00:43:59.803" Score="26" Body="&lt;p&gt;10 seconds is a worthwhile warning time. The Japanese use it to switch off compressors on gas lines (or open release valves on them), emergency break bullet trains, and in particular shut down nuclear power plants, all in anticipation of a power loss moments later. In the case of Japan, however, the warning time doesn't come from having &lt;em&gt;deep&lt;/em&gt; sensors, but from having sensors everywhere -- and getting the advance warning because earthquake waves don't just travel upward, but along the earth surface for dozens of kilometers before they become too weak to cause much destruction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The issue with drilling down to 50 km is simply that we have neither the technology nor the financial resources. The Germans drilled down to slightly more than 10 km, but it cost a billion dollars. The issues are that (i) it gets incredibly warm at these depths, (ii) you need to rotate a drill at the end of a 10 km long pipe that is so hot that it would rather deform than transmit this torque, (iii) there is tremendous pressure on the sides of the well from the surrounding rock, causing it to push inward (and in the process jamming the drill string). I don't think we'll ever have technology that can drill to a depth of 50 km.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastEditorUserId="269" LastEditDate="2016-01-22T09:01:14.497" LastActivityDate="2016-01-22T09:01:14.497" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="7337" PostTypeId="2" ParentId="7332" CreationDate="2016-01-22T00:51:25.530" Score="28" Body="&lt;p&gt;The simple answer is that you can't drill to 50 km depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The deepest holes ever drilled were to a little more than 12 km, one is named the Kola Superdeep Borehole in Russia, which was a scientific drilling project. The very few others were oil exploration boreholes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Drilling that deep is extremely expensive and hard. If you go and ask anyone who ever worked on a drill rig, drilling the second 100 metres is always harder than the first 100 metres. And we're talking about kilometres here! There are several problems with drilling that deep. It's extremely hot down there, and the drilling equipment just breaks and stops working. You also need to pump cooling water in and pump out the stuff you're drilling and it gets harder with depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is simply not feasible. Now let's say that you did somehow manage to drill a hole to that depth. How would you put monitoring equipment inside? That equipment has to sustain heat and pressure and still keep working, while being able to transmit whatever it's reading back to the surface. This is not going to happen, not at 50 or 10 km depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another problem is that not all earthquakes are that deep. Some earthquakes originate near the surface, or just several km deep. Having a monitoring station down there isn't going to help. The 2011 Tohoku earthquake (the one that triggered the tsunami at Fukushima) was only 30 km deep. Same thing for the 2004 Indian Ocean earthquake.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-01-22T00:51:25.530" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7338" PostTypeId="2" ParentId="2187" CreationDate="2016-01-22T06:31:06.510" Score="2" Body="&lt;p&gt;I can list the cycles and possible cycles that I know of.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You mentioned the &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;nofollow&quot;&gt;Milankovich cycles&lt;/a&gt;, 26,000 (or 21,000), 41,000 and about 100,000 (with some fluctuation), are pretty much like clockwork and are timed pretty well with historical ice ages, so those are confirmed cycles, but they also occur very slowly.   The &lt;a href=&quot;http://www.astrobio.net/news-exclusive/how-earths-orbital-shift-shaped-the-sahara/&quot; rel=&quot;nofollow&quot;&gt;Sahara desert&lt;/a&gt; may cycle from lush rain forest to desert back to rain forest every 26,000 years.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, the orbital changes are not thought to be a big factor today.  We're likely in the middle of a warm period between ice ages, perhaps in a gradual cooling.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Solar Minimums&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sun cycles between high and low sunspot periods on roughly an 11 year cycle.   High sunspot activity does give the Earth slightly more energy but the effect of this is pretty small, maybe 1/4 of 1 degree C maximum to minimum, less than the 1 degree plus that the CO2 has already warmed the earth.    Still 1/4 of 1 degree can have an effect if the sun enters an extended minimum.   This may be the cause of the little ice age.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Maunder_Minimum&quot; rel=&quot;nofollow&quot;&gt;Maunder Minimum&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Maunder_Minimum#Little_Ice_Age&quot; rel=&quot;nofollow&quot;&gt;Little Ice age&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A recent study suggested that the sun might enter a new long term (Maunder like) minimum and that it may happen every few hundred years, but the cooling from this is likely smaller than the warming already experienced from CO2.   (I have a link, need to track it down)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Ocean currents&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is very complex and difficult to predict.  We know that El Ninos and La Nina's tend to roughly alternate.   El Nino's are associated with a warmer ocean current on the surface that warms teh air (and has numerous other global weather effects) and La Nina is a cooler ocean current on the surface that warms the air less/cools it more and there are also predictible weather effects all over the planet.   La Nina and El Nino aren't exactly on a cycle any more than heavy snow fall winters and light snow fall winters are on a cycle, they're more like chance, for lack of a better word, though they must be caused by something but as far as I know there's no good predictive methods beyond a few months ahead of time.   I think it's unlikely that La Nina and El Nino play key roles in global climate change though, but there's no definitive evidence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_oscillation&quot; rel=&quot;nofollow&quot;&gt;Longer term ocean currents&lt;/a&gt; are often used by climate change skeptics, like 30 year ocean cycles, because, if you squint just right, they can argue that the global temperature has risen and fallen on a 30 year cycle.  (They really haven't), but it looks like there could be some truth to that.  See chart here (for some reason I couldn't embed)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www2.ucar.edu/sites/default/files/news/2014/201301-201312.png&quot; rel=&quot;nofollow&quot;&gt;https://www2.ucar.edu/sites/default/files/news/2014/201301-201312.png&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source:  &lt;a href=&quot;https://www2.ucar.edu/climate/faq/how-much-has-global-temperature-risen-last-100-years&quot; rel=&quot;nofollow&quot;&gt;https://www2.ucar.edu/climate/faq/how-much-has-global-temperature-risen-last-100-years&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now it looks like the Earth cooled 1880-1910, warmed 1910-early 1940s, cooled a little / stayed about flat 1940-1975 and warmed 1975 to present.   It sounds like a good argument but 2 periods is much too short a time period to draw any good conclusions, especially if the argument is largely circumstantial without a clear cause and effect, and lets not forget, the warming since the 1970s has blown out of the water any measured 30 year period before then, so the current warming doesn't fit the model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Volcanoes&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While not really a &quot;cycle&quot; &lt;a href=&quot;https://en.wikipedia.org/wiki/Volcanic_winter&quot; rel=&quot;nofollow&quot;&gt;volcanoes&lt;/a&gt; can have measurable effects on climate, but only very large ones, so this happens maybe 1-2 times a century.  The last cooling volcano happened in 1991 and may have cooled the earth about 1/2 of 1 degree, which is actually a lot, but it's also, quite temporary.  A few years after the Volcano the Earth was setting heat records again and by 1998 with the large El Nino, global temperatures blew the previous records out of the water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Liars&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;see chart here:   &lt;a href=&quot;http://www.drroyspencer.com/global-warming-background-articles/2000-years-of-global-temperatures/&quot; rel=&quot;nofollow&quot;&gt;http://www.drroyspencer.com/global-warming-background-articles/2000-years-of-global-temperatures/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Roy Spencer suggests that during the medieval warm period it was 1 or 2 degrees hotter than today.   I think he's basically lying because he's the only person producing charts like this.  There's another scientist (I forget his name) who only studies the Greenland ice sheet which can be prone to local variations and not give a good picture of global temperatures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Locally there can be fairly significant temperature variation but, and this is important, there's a difference between natural variation and cycles.  Cycles by definition have causes.   Natural variation tends to be more local than global, though there are global variations year to year, where the biggest drivers are probably El Nino/La Nina and the occasional once in a century volcanic eruption.   Other smaller effects like cloud cover and snow cover/reflection probably play roles too.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But in a certain sense, all this is just movement of temperature and (OK clouds and snow can reflect solar energy away directly) but oceans, the primary cause used for cycles don't change the total heat in the system so much as they move it around.  The sun, another commonly misused cause for cycles, doesn't vary enough to explain the current warming, so it's likely that most of the people saying &quot;it's a cycle&quot; are simply wrong.   Though it's possible that part of the warming is riding a so far unexplained cycle, it's very unlikely that most of it is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The simplest way to look at climate change is energy in and energy out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://earthobservatory.nasa.gov/Features/EnergyBalance/page4.php&quot; rel=&quot;nofollow&quot;&gt;http://earthobservatory.nasa.gov/Features/EnergyBalance/page4.php&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is grossly over simplified but 29% of the suns energy is reflected directly back into space, 23% warms the atmosphere and 48% warms the surface.   The earth, when in equilibrium, gives back the same amount of energy that it receives, of that 71%, only 12% radiates from the surface of the earth and 59% radiates into space from the atmosphere.   Small changes in radiation away from the earth (which is how greenhouse gas works) gradually increase the total heat of the earth, and most of this heat goes into the oceans, some melts ice and only about 3% stays in the atmosphere, which slowly warms the atmosphere, the current estimate is about 2 degrees C every 100 years (and the ocean warming, likely even slower than that, maybe 1 degree on the surface every 100 years or more and even more gradual warming in the middle and deeper oceans.  All that is very one-dimensional as it doesn't take into account evaporation and cloud formation, changes in plant transporation, changes in desert vs green land cover, changes in ice cover, humidity etc.   It's a hugely complicated system, BUT, there is very good evidence that the atmosphere is trapping heat and the earth is taking in more energy from the sun than it is currently returning to space and that's the single most important bit of evidence.   So called 30 year ocean cycles are very much worth studying but likely not causing and unlikely to prevent man made climate change.   Solar cycles are worth studying and may even exist over every few centuries, but they are probably too small to prevent the greenhouse gas warming.    Other &quot;undiscovered&quot; cycles, well, sounds good, but without a testable theory, that's not real science. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That was probably too long, but there it is.    &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2016-01-22T06:31:06.510" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7339" PostTypeId="2" ParentId="7329" CreationDate="2016-01-22T10:31:55.890" Score="10" Body="&lt;p&gt;This question (if you can call it like this) is &lt;a href=&quot;http://rationalwiki.org/wiki/Not_even_wrong&quot;&gt;not even wrong&lt;/a&gt;. Let's ignore the fact that the title has little to do with the actual content of the question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's discuss your statement:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If this occurred 120,000 years ago and seems to be taking place again, Man is not the cause behind Greenland's glacial melting.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There is no logical part between the first part of the sentence to the second part. Let's change it a bit:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Forest fires occurred 120,000 years ago and seems to be taking place again, Man is not the cause behind forest fires.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes, forest fires happened 120000 years ago. Also a million years ago. Also 100 million years ago. And now. But now, forest fires are started by people throwing away cigarettes and not putting out their campfires properly. Does that mean that all modern forest fires are because of natural causes? No. I hope this analogy helps you understand the logical fallacy in what you wrote.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, to your question:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If global warming by man is not causing Greenland's ice sheets to melt, What natural source could be?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But global warming by humanity &lt;em&gt;is&lt;/em&gt; causing ice sheets to melt. Therefore your question is invalid. I will not try to answer the hypothetical case that it is natural, because that will just be taken out of context and used as ammunition by climate change deniers, as always happens.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-01-22T10:31:55.890" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7340" PostTypeId="2" ParentId="7299" CreationDate="2016-01-22T11:00:25.743" Score="2" Body="&lt;p&gt;I'll add to Ben MS's answer by mentioning the 2010 eruption of Eyjafjallajökull in Iceland, that shut down air traffic for quite some time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another example that comes to mind are tsunamis. The 2004 tsunami in the Indian Ocean mostly affect South East Asia: Indonesia, Thailand, Sri Lanka, and the eastern part of India. But other areas were affected as well, for example in Africa: Somalia, Kenya and the neighbouring Yemen. Here's a map:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bvGVA.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bvGVA.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another example is the Fukushima disaster in Japan, triggered by an earthquake. Some of the radioactive stuff may have ended up in America (although not everyone is convinced of that, and the scary maps you see online are not actually true).&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-01-22T11:00:25.743" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7341" PostTypeId="1" CreationDate="2016-01-22T11:32:42.237" Score="3" ViewCount="66" Body="&lt;p&gt;At work (at a local authority), I have a flood zone plan/layer that was created using ArcGIS software from an Elevation Model which has an accuracy of 1 metre. The zone covers an urban area. I cannot get to the resolution of which buildings will be more effected by flood and which won't, but I do have a layer of all buildings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question is, whether I should cut the buildings out of the flood zone, and why?&lt;/p&gt;&#xA;" OwnerUserId="5265" LastEditorUserId="2470" LastEditDate="2016-01-22T12:46:45.520" LastActivityDate="2016-01-23T00:59:45.403" Title="Should I cut buildings from flood zone?" Tags="|water|flooding|urban-climate|" AnswerCount="1" CommentCount="5" ClosedDate="2016-01-23T01:39:55.357" ContentLicense="CC BY-SA 3.0" />
  <row Id="7343" PostTypeId="2" ParentId="7329" CreationDate="2016-01-22T19:04:31.647" Score="2" Body="&lt;p&gt;The changes of climate in the past you're talking about occurred mainly because of the periodic change of earth's movements relatively to the sun. For example the swinging rotational axis of the earth and the changing orbit (sometimes a very flat ellipsoid, then again more like a circle) around the sun. This leads to the periodic change you were talking about.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Though big ice shields will lower earth's temperature because the higher reflection of the sunlight..&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But also changing weathering rates on earth or events of many or big volcanic eruptions can change the climate, since the composition of atmosphere's gases can change drastically.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have to admit that I'm not sure about how the water circulation affects the whole process, but I think if even the pole shields melt there is a low chance it'll start to get frosty somewhere else.. if you open the refrigerator it will get colder around it, but never as cold as it was in it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But for the current climate change it seems pretty obvious that it's our fault. Compare some pollutionew and temperature diagrams compared to temperature diagrams from long ago.. you'll see the connection.&lt;/p&gt;&#xA;" OwnerUserId="5274" LastEditorUserId="5274" LastEditDate="2016-01-22T19:10:44.217" LastActivityDate="2016-01-22T19:10:44.217" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7345" PostTypeId="2" ParentId="517" CreationDate="2016-01-23T00:21:12.647" Score="4" Body="&lt;p&gt;In 1906, Richard D. Oldham found that the increasing speed of seismic waves with depth within the Earth holds only down to 2890 km below the surface. Deeper than that, the mechanical waves (sound) propagate much slower, suggesting a different rock nature. Because this distinct material did not transmit &lt;strong&gt;shear seismic waves&lt;/strong&gt;, it became clear that this core is liquid. This is what we call the &lt;strong&gt;Earth's core&lt;/strong&gt;. Its size is known because the farther your seismometer is from a earthquake hypocenter, the deeper the registered seismic waves have travelled: since the velocity of sound increases with depth down to the core, seismic &lt;em&gt;rays&lt;/em&gt; are refracted and they curve back towards the surface. Because the velocity-depth relation breaks abruptly at the core-mantle boundary, this is clearly detected in seismographs. I link this &lt;a href=&quot;http://retosterricolas.blogspot.com/2015/09/how-do-we-know-earth-has-core.html&quot; rel=&quot;nofollow&quot;&gt;example of how to use seismic refractions to determine the size of the core&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In 1936, Inge Lehmann, using the same technique, found that the center of the core is indeed nearly-solid, because she detected weak shear waves travelling through it [2] using highly-sensitive seismometers in New Zealand. This has become known as the &lt;strong&gt;inner core&lt;/strong&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[2]: Lehmann, I., P'. Publ. Int. Geod. Geophys. Union, Assoc. Seismol., Ser. A, Trav. Sci., 1936, 14, 87-115.&lt;/p&gt;&#xA;" OwnerUserId="1379" LastActivityDate="2016-01-23T00:21:12.647" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7346" PostTypeId="2" ParentId="7341" CreationDate="2016-01-23T00:59:45.403" Score="0" Body="&lt;p&gt;Since it is not known at this stage what measures were implemented for each building in regard with eventual flood situations, it does not make sense to purposely exclude the buildings from the flood zone until some kind of general database with that info is built and put into context in your system. Even-more, a lot could happen in a potential flood zone when an extreme event occurs, regardless of the prevention plan by various owners and city management. A risk management model with proper risk probabilities, potential damages and monetary values would eventually be required to better represent the up-to-date context of the site.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2016-01-23T00:59:45.403" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7347" PostTypeId="2" ParentId="7332" CreationDate="2016-01-23T07:45:28.113" Score="1" Body="&lt;p&gt;The cost of digging very deep boreholes is generally prohibitive and unnecessary given the accuracy that detectors can be built with modern technology and the time advantages of deep mine detectors is minimal given the velocity of wave propagation through a solid. The Tevatron Particle Accelerator in the US was able to detect earth quakes from the other side of the world during its operation.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Japan has started to put vital services such as Water, Power and Gas in very very deep utility tunnels ( 1km+ deep ) as they are only minimally affected at the deeper depth by Earthquakes, the seismic shift is greatly reduced ( About 1-3cm ) and oscillations occur at a different frequency. In most of the great earthquakes to hit Japan most people have been killed not by building collapse but by incidents caused by ruptured utilities and the aftermath of having no services ie access to clean water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These deep service tunnels are also populated with seismic detectors as they are insulated from surface vibrations and provide a stable baseline for earthquake detection and monitoring.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This massive change in city planning demonstrates that advanced warning alone is not enough to protect a city and its inhabitants.&lt;/p&gt;&#xA;" OwnerUserId="5278" LastEditorUserId="5278" LastEditDate="2016-01-26T22:13:06.517" LastActivityDate="2016-01-26T22:13:06.517" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7348" PostTypeId="1" CreationDate="2016-01-23T10:05:33.313" Score="2" ViewCount="465" Body="&lt;p&gt;While watching lightning activity in the sky from afar, a natural curiosity welled within me. What are the exact locations where those lightning bolts strike?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All these questions appear because of my ignorance of this natural phenomenon. I hope any lightning experts out there can help me understand, what exactly makes a spot a possible candidate for the lightning to strike? Has a list all past lightning-struck locations been compiled?&lt;/p&gt;&#xA;" OwnerUserId="5279" LastEditorUserId="2470" LastEditDate="2016-01-24T00:50:43.573" LastActivityDate="2016-01-24T00:50:43.573" Title="Where does lightning strike?" Tags="|lightning|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7349" PostTypeId="2" ParentId="7330" CreationDate="2016-01-23T12:29:36.880" Score="6" Body="&lt;p&gt;The most authoritative source for weather data in Germany is the German Weather Service (DWD). They have a climate data center that by now provides historical data free of charge. You can find it here: &lt;a href=&quot;http://www.dwd.de/EN/climate_environment/cdc/cdc_node.html&quot; rel=&quot;nofollow&quot;&gt;http://www.dwd.de/EN/climate_environment/cdc/cdc_node.html&lt;/a&gt; (it appears some knowledge of German might be helpful.)&lt;/p&gt;&#xA;" OwnerUserId="681" LastEditorUserId="681" LastEditDate="2016-01-23T17:09:02.520" LastActivityDate="2016-01-23T17:09:02.520" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7350" PostTypeId="1" AcceptedAnswerId="7351" CreationDate="2016-01-23T17:08:12.317" Score="10" ViewCount="14822" Body="&lt;p&gt;I am curious how can one have an idea of grid resolution. How much is the distance resolution in km of a grid with resolution of 0.5 deg x 0.666 deg?&lt;/p&gt;&#xA;" OwnerUserId="5122" LastEditorUserId="192" LastEditDate="2016-01-24T03:48:40.517" LastActivityDate="2016-01-24T07:21:29.463" Title="Converting grid resolution from degrees to kilometers" Tags="|models|grid-spacing|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7351" PostTypeId="2" ParentId="7350" CreationDate="2016-01-23T17:19:40.883" Score="11" Body="&lt;p&gt;Assuming spherical shape, Earth's circumference is about $40,000\mathrm{km}$. These are split into $360^\circ$, so one degree is a bit more than $100\mathrm{km}$. This is true for latitudes. For longitudes, the circles of constant latitude are shorter as you move away from the equator. Therefore you need to multiply that number by $\cos(latitude)$. To summarize, if $R_e$ is Earth's radius, we got&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\Delta y=2\pi R_e\frac{\Delta lat}{360^\circ}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\Delta x=2\pi R_e\cos(lat)\frac{\Delta lon}{360^\circ}.$$&#xA;Note that here I am using $\Delta x$ and $\Delta y$ for the resolution in a cartesian frame with $y$ pointing south-north and $x$ pointing west-east. For your numbers, think about it as around $50\mathrm{km}$ resolution.&lt;/p&gt;&#xA;" OwnerUserId="681" LastEditorUserId="681" LastEditDate="2016-01-24T07:21:29.463" LastActivityDate="2016-01-24T07:21:29.463" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="7352" PostTypeId="1" AcceptedAnswerId="7353" CreationDate="2016-01-23T18:05:48.853" Score="4" ViewCount="101" Body="&lt;p&gt;I know that aurorae are caused by solar activity interacting with the Earth's magnetic field as charged particles are funneled down into the polar &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnetic_mirror&quot; rel=&quot;nofollow&quot;&gt;magnetic mirrors&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;On one hand, I know that as charged particles accelerate, they will produce radiation. They will happen in at least two ways in the context of aurorae: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Charged particles will gyrate around magnetic field lines with a characteristic frequency, which presumably varies with pitch angle and position in Earth's magnetic field. &lt;/li&gt;&#xA;&lt;li&gt;As the charged particles are slowed down by the magnetic mirror effect, they will release some radiation. &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I've also heard that the visible radiation is caused by re-radiation from oxygen or nitrogen atoms which have been excited by collisions with these charged particles. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which effects cause radiation at which wavelengths/frequencies, and what actually causes the visible aurorae? &lt;/p&gt;&#xA;" OwnerUserId="4439" LastActivityDate="2016-01-23T22:12:16.360" Title="What causes aurorae?" Tags="|atmospheric-radiation|electromagnetism|auroras|magnetosphere|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7353" PostTypeId="2" ParentId="7352" CreationDate="2016-01-23T22:12:16.360" Score="3" Body="&lt;p&gt;When the solar wind is funneled into the Earth's magnetic poles, those particles excite the electrons of molecules in the atmosphere which then bumps those electrons up into another orbital. When the electrons fall back down into their native orbital, they produce a photon of a particular wavelength whose energy is equal to the difference between the energy states of the two orbitals.&lt;br&gt;&lt;br&gt;There is a good pdf from NASA &lt;a href=&quot;http://pwg.gsfc.nasa.gov/polar/telecons/archive/PR_E-PO/Aurora_flyer/aurora-flyer_p2.doc.pdf&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt; and another good article &lt;a href=&quot;http://www.atoptics.co.uk/highsky/auror3.htm&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2016-01-23T22:12:16.360" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7354" PostTypeId="1" CreationDate="2016-01-23T22:38:00.147" Score="1" ViewCount="85" Body="&lt;p&gt;Theoretically, I ponder what type and strength a supereruption would generate, say for example at the Yellowstone caldera? The last supereruption was roughly 70,000 years ago when Toba erupted. It's claimed that this single event bottlenecked our species and nearly ended us? My curiosity is more towards the effects in the immediate vicinity of the collapse, in particular the seismic effects and their severity? Large quakes and tsunamis if near ocean? &lt;/p&gt;&#xA;" OwnerUserId="5286" LastEditorUserId="725" LastEditDate="2016-01-24T04:36:07.773" LastActivityDate="2016-01-25T23:44:01.860" Title="Earthquake severity during supereruption at Yellowstone caldera?" Tags="|volcanology|volcanic-hazard|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7355" PostTypeId="1" CreationDate="2016-01-24T08:33:33.390" Score="4" ViewCount="473" Body="&lt;p&gt;I was reading about the discovery of vast amounts of water locked up in ringwoodite (see &lt;a href=&quot;http://www.bbc.com/future/story/20141029-are-oceans-hiding-inside-earth&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;). The authors of the study seem to suggest that previous ideas, involving water deposits being delivered by comets, were brought in to question by the ringwoodite discovery, and that this water was there from the Earth's formation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there no means through which such a large volume of surface water, perhaps delivered by comets, could be subsumed in to the mantle through tectonic processes? &lt;/p&gt;&#xA;" OwnerUserId="5290" LastEditorUserId="725" LastEditDate="2016-01-24T11:27:46.410" LastActivityDate="2016-01-24T11:41:44.170" Title="Source of sub-surface ringwoodite water" Tags="|geochemistry|planetary-science|water|tectonics|mantle|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7356" PostTypeId="1" AcceptedAnswerId="7361" CreationDate="2016-01-24T09:03:16.893" Score="9" ViewCount="221" Body="&lt;p&gt;Plate tectonics effectively rubbished the theory of geophysical global cooling as a means of explaining many surface features on the Earth. However, &lt;a href=&quot;https://en.wikipedia.org/wiki/Geophysical_global_cooling&quot; rel=&quot;nofollow&quot;&gt;this wiki&lt;/a&gt; says that the same process is responsible for certain surface features on the surfaces of Mercury and the Moon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do such processes play no role in Earth's Geology? Or are they only effective on smaller bodies? Why?&lt;/p&gt;&#xA;" OwnerUserId="5290" LastEditorUserId="543" LastEditDate="2016-01-29T08:27:45.020" LastActivityDate="2016-01-29T08:27:45.020" Title="What is the current status of geophysical global cooling theory?" Tags="|geophysics|geology|planetary-science|tectonics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7357" PostTypeId="2" ParentId="7355" CreationDate="2016-01-24T11:41:44.170" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is there no means through which such a large volume of surface water, perhaps delivered by comets, could be subsumed in to the mantle through tectonic processes?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Definitely. This was happening throughout most of Earth's history, it's happening now, and it will happen in the future.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Subduction occurring in subduction zones are the main mechanism (only mechanism?) of taking stuff from the surface and pushing it down deep into the mantle. Oceanic crust gets hydrated by reacting with the ocean water. Primary magmatic minerals such as pyroxene and olivine are altered into a variety of hydrous minerals: serpentine, amphibole, epidote, chlorite, talc, etc. Once this hydrated crust gets subducted most of the water is volatilised and gets lost to overlying mantle, and even flux-melting it so you end up having volcanoes. Here's a picture:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Vupal.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Vupal.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;Source: &lt;a href=&quot;http://www.nature.com/nature/journal/v417/n6888/fig_tab/417497a_F1.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;nature.com&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recent research shows that not all water is lost. Some of it may actually survive the way down deep into the mantle. The identity of the carrier minerals and the exact conditions are still a field of active research and new discoveries are constantly being made. This would most likely form water-rich and water-poor regions in the mantle. The water content of the mantle will thus be quite heterogeneous, which raises the question of how representative was the ringwoodite discovery. After all, it's only one data point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to summarise it, yes. Water from the surface can end up in the mantle. This doesn't necessarily mean that this is what is happening, and it may be equally likely that the mantle water is indeed primordial.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-01-24T11:41:44.170" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7359" PostTypeId="2" ParentId="7310" CreationDate="2016-01-25T00:47:51.613" Score="4" Body="&lt;p&gt;Each one of the monitor siting examples you list has a different purpose.  As you have listed, a monitor will be sited for air regulatory compliance purposes (e.g. determining the highest concentrations downwind of a major source), understanding the region (e.g. representative site in well-mixed location), or health exposure risks (e.g. densely populated areas). From a health and regulatory perspective, those types of site locations are sufficient.  However, you may want to consider other monitor site locations in your network that will help to evaluate the performance of the air quality model and assess the importance of various sources:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Monitors at a variety of elevations, so that vertical mixing can be evaluated (or use sondes)&lt;/li&gt;&#xA;&lt;li&gt;Monitors both upwind and downwind of major sources, so that their contributions can be determined to a greater accuracy than represented in the original emissions inventory.&lt;/li&gt;&#xA;&lt;li&gt;Monitors behind complex terrain, which affects transport, and can be difficult to model correctly.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Air quality modeling helps to fill in the gaps left by monitoring networks, since they are expensive to site and maintain.  Monitor networks are relatively sparse compared to the number of major source and receptor locations.  So, it is important to carefully consider each site location and pick ones that satisfy multiple criteria.  Satellite retrievals and local testimonials can be used to evaluate the initial value of your network.  However, you will benefit from quality controlling your model in the areas where your model performs poorly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For reference, here is an example of how modeling and air monitors can be used together to make quality forecasts.  Environment and Climate Change Canada’s &lt;a href=&quot;https://weather.gc.ca/aqfm/index_e.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;FireWork&lt;/a&gt; air quality (AQ) forecast system for North America with wildfire emissions has a post process called UMOS-AQ (see below).  The Canadian researchers built a system that modifies their air quality predictions based on recent surface monitor model/observations comparisons.  The Regional Air Quality Deterministic Prediction System (RAQDPS)uses GEM-MACH (Global Environmental Multi-scale - Modelling Air quality and CHemistry) and BlueSky Canada.  Here is a &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5062048/&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt; that describes the process.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The RAQDPS includes other components besides GEM-MACH. One postprocessing product is the Updateable Model Output Statistics for Air Quality (UMOS-AQ) package, which applies statistics for bias correction to compensate for systematic AQ model errors and account for unresolved subgrid-scale phenomena at particular locations, namely the locations of AQ measurement stations (Wilson and Vallée, 2002; Antonopoulos et al., 2010; Moran et al., 2012). Hourly model forecasts of both pollutant concentrations and meteorological quantities at specific locations are combined with available hourly surface AQ measurements to generate location-specific hourly statistical forecasts for areas where AQ is measured. The location-specific O3, PM2.5, and NO2 concentrations calculated by UMOS-AQ are also the ones used in the calculation of the AQHI values that are disseminated to the public.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2017-01-10T06:11:26.063" LastActivityDate="2017-01-10T06:11:26.063" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7360" PostTypeId="2" ParentId="7354" CreationDate="2016-01-25T01:15:18.063" Score="3" Body="&lt;p&gt;Volcanic earthquakes aren't actually all that strong. That's quite easily understandable by just looking at length scales: In the largest earthquakes that happen on earth, tens of kilometers of subduction zones rupture at once, releasing the stress that has built up from two plates moving past each other (but being locked) for decades. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even large calderas cannot produce faults of this length that are sufficiently long and linear and can rupture in the same quake. Consequently, earthquakes in volcanic zones are usually much smaller than the largest ones we experience on earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The global effects of supereruptions are not due to earthquakes or tsunamis, but due to the gases, ash and sulphur that ends up in the atmosphere and that leads to global cooling for several years.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastEditorUserId="5259" LastEditDate="2016-01-25T23:44:01.860" LastActivityDate="2016-01-25T23:44:01.860" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7361" PostTypeId="2" ParentId="7356" CreationDate="2016-01-25T01:24:13.363" Score="5" Body="&lt;p&gt;The effects one can see on other planets (and many of the icy moons in the solar system) are typically faults and scarps due to the fact that during cooling, these bodies contracted. Since the surface was solid, the only way to accommodate the contraction is through faults.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But Earth's surface is not solid on long time scales. We have plates that move, scrape, and subduct. If you shrink the perimeter of Earth slowly, you don't get compression faults. Rather, you're just going to accelerate subduction a little bit and maybe slow down mid-ocean ridges a bit. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the end, the point is that the system of plates that covers Earth can accommodate slow shrinkage of Earth without producing visible faults.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2016-01-25T01:24:13.363" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7362" PostTypeId="1" AcceptedAnswerId="7382" CreationDate="2016-01-25T04:18:17.943" Score="8" ViewCount="1269" Body="&lt;p&gt;The peak period or peak frequency is considered to be an important quantity in characterizing ocean surface waves, including wave models [e.g., &lt;a href=&quot;http://dx.doi.org/10.1016/j.coastaleng.2005.12.006&quot;&gt;1&lt;/a&gt;]. But practically, why are we interested in modelling the peak period accurately? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm thinking the peak frequency directly translates to how fast the dominant waves propagate, and so is important to predicting when the waves will reach coastal locations of interest. Is this thinking correct?&lt;/p&gt;&#xA;" OwnerUserId="2645" LastActivityDate="2016-05-22T09:53:00.903" Title="The significance of peak period in surface wave models" Tags="|ocean|waves|wave-modeling|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7363" PostTypeId="1" AcceptedAnswerId="12373" CreationDate="2016-01-25T09:28:32.357" Score="6" ViewCount="150" Body="&lt;p&gt;I have GOES 15 satellite image data (GVAR_IMG) for a project that I am working on.  The files are end in .BAND_01, .BAND_02, etc. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I use the &lt;a href=&quot;https://www.giss.nasa.gov/tools/panoply/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Panoply tool&lt;/a&gt; to view these files, but am looking for an online tool or software to convert this data into solar irradiance values.&lt;/p&gt;&#xA;" OwnerUserId="5294" LastEditorUserId="6298" LastEditDate="2017-09-26T17:25:14.513" LastActivityDate="2017-12-15T08:45:23.067" Title="Convert satellite image data (GOES 15) into solar irradiance values?" Tags="|meteorology|software|solar-terrestrial-physics|weather-satellites|geospatial|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7364" PostTypeId="2" ParentId="7281" CreationDate="2016-01-25T11:40:47.300" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;What is the Moon's distance from viewer at horizon?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As noted by others, the moon follows an elliptical orbit, which will lead to the greatest change in distance regardless of the observation angle. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, we can place some upper and lower bounds on what the distance at the horizon would be by using the maximum and minimum orbital radii (the apogee and perigee respectively) along with Pythagoras's theorem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CfEF5.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CfEF5.jpg&quot; alt=&quot;earth-moon-horizon&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the image above, the larger circle represents the Earth, and the smaller is the Moon. $R$ is the radius of the Earth, $d$ is the orbital distance of the moon from the Earth's centre, and $x$ is the distance of the Moon from the observer when the Moon is on the horizon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pythagoras's theorem states that&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$d^2 = x^2 + R^2$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which we can rearrange to give $x$,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$x = \sqrt{d^2 - R^2}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now just substitue the numbers in. I used the following values from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Orbit_of_the_Moon&quot; rel=&quot;nofollow noreferrer&quot;&gt;Orbit of the Moon wiki&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Perigee: 362600 km, Apogee: 405400 km, average orbital distance: 385000km, radius of the Earth: 6371km&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At Apogee, $x$ = 405349 km&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At Perigee, $x$ = 362544 km&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At average orbital distance, $x$ = 384947 km&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;From a viewers standpoint When the moon starts to rise at the horizon, Is the moon at the furthest distance from the viewer visually?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As noted above, viewing angle is not the primary factor in the distance calculation. However, for a given point in its orbit, the Moon is at its &lt;em&gt;furthest&lt;/em&gt; visible radius from the Earth at the Horizon. We can see this by comparing to the Moons distance when directly above the observer. This will be the Moon's orbital radius minus the radius of the Earth. For each orbital point this is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At Perigee: 356229 km, at Apogee: 399029 km, at average orbital distance: 378629 km&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each of which is around 6300 km closer than when the same orbital configuration is viewed at the Horizon. The Moon may &lt;em&gt;appear&lt;/em&gt; larger at the horizon, and hence closer, but this is an &lt;a href=&quot;https://en.wikipedia.org/wiki/Moon_illusion&quot; rel=&quot;nofollow noreferrer&quot;&gt;illusion&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Moon differs from most satellites of other planets in that its orbit is close to the plane of the ecliptic, and not to Earth's equatorial plane&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;For the horizon distance, the position of the observer on the Earth makes no difference: when the Moon is at the Horizon the distance, for a given orbital configuration, will be the same (minus altitude differences on the Earth's surface). However, from some observational positions the Moon will never be directly above, so the second part is location dependent.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I want one source from each of the following governments sites- ( U.K gov)(Russian gov)and (Chinese gov) and the sources HAVE to all state a ''similar'' distance.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I doubt that this data is available publicly on government websites. If it was, you could probably find it yourself.&lt;/p&gt;&#xA;" OwnerUserId="5290" LastActivityDate="2016-01-25T11:40:47.300" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7367" PostTypeId="2" ParentId="221" CreationDate="2016-01-25T22:23:33.833" Score="0" Body="&lt;p&gt;I would imagine two factors are involved. The source and the media. The vibration of source and its spectra has to do with its mass and stiffness. The propagation of the seismic wave and its attenuation has to do with media. Admittedly both hard to quantify, but with known geology of local and surrounding area it is possible to estimate the frequency and acceleration.&lt;/p&gt;&#xA;" OwnerUserId="5303" LastActivityDate="2016-01-25T22:23:33.833" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7368" PostTypeId="2" ParentId="7362" CreationDate="2016-01-25T23:41:21.160" Score="2" Body="&lt;p&gt;The peak period is also important in evaluating the interaction of waves and human-built structures such as drilling platforms. If the frequencies of resonance of a drilling platform coincide with the peak frequency of waves, you will get rather sea sick occupants or, more seriously, structural failure. All platforms are designed to tune their resonance frequencies away from common wave frequencies.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastEditorUserId="5259" LastEditDate="2016-01-27T03:58:53.963" LastActivityDate="2016-01-27T03:58:53.963" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7370" PostTypeId="1" AcceptedAnswerId="7373" CreationDate="2016-01-26T05:40:26.827" Score="5" ViewCount="258" Body="&lt;p&gt;I understand that soil color is affected by several factors some of which are (but not limited to):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;organic matter content&lt;/li&gt;&#xA;&lt;li&gt;underlying parent material&lt;/li&gt;&#xA;&lt;li&gt;drainage and aeration&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Soil color being an indirect measure of other important characteristics (Foth, 1990), I have been thinking about building an application that reads a soil color in terms of it's hue, value, and chroma as the &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Munsell_color_system&quot; rel=&quot;nofollow noreferrer&quot;&gt;munsell color system&lt;/a&gt; using &lt;a href=&quot;http://opencv.org&quot; rel=&quot;nofollow noreferrer&quot;&gt;openCV&lt;/a&gt; color detection techniques.&lt;/p&gt;&#xA;&lt;p&gt;After reading this data, the application should be able to interpret it to give meaningful information about the soil. This can be organic matter content, dominant minerals, drainage etc.&lt;/p&gt;&#xA;&lt;p&gt;My questions now&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;What information be accurately be obtained from soil color?&lt;/li&gt;&#xA;&lt;li&gt;Is this application by any means feasible?&lt;/li&gt;&#xA;&lt;li&gt;Do technologies exist that achieve the same? (using computer vision)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Reference&#xA;Foth D. (1990). &lt;em&gt;&lt;strong&gt;Fundamentals of soil science&lt;/strong&gt;&lt;/em&gt; J Willey.&lt;/p&gt;&#xA;" OwnerUserId="5273" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-03-28T07:39:01.840" Title="Can soil color give accurate data about properties which affect it?" Tags="|geology|soil|technology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7371" PostTypeId="1" AcceptedAnswerId="7376" CreationDate="2016-01-26T06:32:57.193" Score="16" ViewCount="2780" Body="&lt;p&gt;2015 had the &lt;a href=&quot;https://www.washingtonpost.com/news/energy-environment/wp/2016/01/20/its-official-2015-smashed-2014s-global-temperature-record-it-wasnt-even-close/&quot; rel=&quot;nofollow noreferrer&quot;&gt;highest global temperatures on record&lt;/a&gt;, as discussed in &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7316/why-is-the-temperature-still-rising&quot;&gt;this question&lt;/a&gt;, beating the last record ... in 2014. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HzU6v.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HzU6v.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are we now in a &lt;a href=&quot;https://en.wikipedia.org/wiki/Runaway_climate_change&quot; rel=&quot;nofollow noreferrer&quot;&gt;runaway climate change&lt;/a&gt; regime, where zero further human impact on the environment will not prevent change to the equilibrium state of the Earth's atmosphere?&lt;/p&gt;&#xA;" OwnerUserId="5290" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-01-27T20:38:59.270" Title="Is 2015's record average temperature evidence that we are now experiencing runaway climate change?" Tags="|climate-change|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7373" PostTypeId="2" ParentId="7370" CreationDate="2016-01-26T10:19:53.280" Score="6" Body="&lt;p&gt;Unfortunately, the color itself won't give you much more information than the amount of organic matter and oxides/hydroxides. The amount of carbonate and some silicates might also be detected, but those values would be very vague without further examination of the soil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to get more information you would need some more data. The grain sizes for example (sand, clay, silt), pH-measurements, the amount of water and air, what other minerals and the salinity. You also need information about the soil biota, and so on. To collect all these data you need further research methods.&#xA;So your project idea is nice, but a picture alone won't bring you much information since the soil's properties are too complex.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also writing such a program (I guess a mobile app?) will be hard since all cameras take different pictures under different lighting.. furthermore they all have a different processing of the pictures.&#xA;I'm not sure how computer vision could help since you'd need a special camera. So if you want to make an app you're going to have a hard time. I don't think you want to design a special device just for this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another aspect is that whenever you work with soil, you're going to get dirty. That's no good environment for such technology, that's why the munsell charts are used. It's no problem when they get dirty. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I really like the idea, but I don't think it'll get you far, but that's just my opinion!&lt;/p&gt;&#xA;" OwnerUserId="5274" LastEditorUserId="2536" LastEditDate="2017-03-27T10:27:58.507" LastActivityDate="2017-03-27T10:27:58.507" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7374" PostTypeId="1" CreationDate="2016-01-26T10:47:22.230" Score="3" ViewCount="58" Body="&lt;p&gt;Is there a data source for cumultative global precipitation by year? Units would presumably be mass, volume, or height of water equivalent. Also, what about cumulative global precipitation over land by year? &lt;/p&gt;&#xA;" OwnerUserId="5307" LastEditorUserId="543" LastEditDate="2016-01-29T08:22:59.313" LastActivityDate="2016-01-29T08:22:59.313" Title="Is there a data source for annual global precipitation?" Tags="|climate|precipitation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7375" PostTypeId="2" ParentId="7374" CreationDate="2016-01-26T10:51:15.627" Score="3" Body="&lt;p&gt;In case you want to learn something about precipitation first:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nasa.gov/mission_pages/GPM/main/index.html&quot; rel=&quot;nofollow&quot;&gt;http://www.nasa.gov/mission_pages/GPM/main/index.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is the most important information about current missions with some videos, too.&#xA;If you click on the education link a little lower on the page you can learn a lot about how the data is retrieved and about earth's water cycle itself.. if that's not interesting to you and you just want the data this here is the right way:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://giovanni.sci.gsfc.nasa.gov/giovanni/&quot; rel=&quot;nofollow&quot;&gt;http://giovanni.sci.gsfc.nasa.gov/giovanni/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The site does not just provide data about precipitation but about all measurements that are made from space such as amounts of aerosols, evaporation rates, heat flux, vegetation, wind speed and so on.. you'll see it all on the left site of the page.. just make a tick on the dataset you need and all measurements will pop up on the middle of the screen, make another tick on the information that suits your needs, choose the time span you wish and the area of the map you want to know more about under &quot;show map&quot;.. if you're done with that just click &quot;Plot data&quot; on the right bottom corner and a map with the data you wish will show up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope that helps!&lt;/p&gt;&#xA;" OwnerUserId="5274" LastEditorUserId="5274" LastEditDate="2016-01-27T17:53:40.893" LastActivityDate="2016-01-27T17:53:40.893" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7376" PostTypeId="2" ParentId="7371" CreationDate="2016-01-26T11:16:28.900" Score="22" Body="&lt;p&gt;Runaway climate change is, given our current state of knowledge, only something that could be confirmed in historic context - in the rear-view mirror. Inconveniently, there's likely to be a much-diminished version of human civilisation around to observe it, if and when it does happen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, it's too early to tell if we've passed a catastrophic tipping point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We don't know what the equilibrium state of the Earth's atmosphere is. It will take 30 years for our current stock of GHG emissions to fully show its effects: and we'll be continuing to release GHGs for a while, so the equilibrium will continue to change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But it's worth bearing in mind what we can do, when we really have to; World War II saw massive realignments both in industrial production and in expectations within a very short space of time: after decades of delay, it now seems likely that decarbonisation will require at least a similarly fast and large industrial realignment; and it is possible.&lt;/p&gt;&#xA;" OwnerUserId="100" LastActivityDate="2016-01-26T11:16:28.900" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7377" PostTypeId="1" CreationDate="2016-01-26T11:56:20.260" Score="2" ViewCount="854" Body="&lt;p&gt;Has anyone attempted to classify global photosynthesis? For example, what percentage of it occurs over land? What percentage comes from agriculture? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Same questions for total growth of plant mass.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There will of course be issues with definition and measurement. But any attempts at answers would still be interesting.&lt;/p&gt;&#xA;" OwnerUserId="5307" LastEditorUserId="543" LastEditDate="2016-01-29T08:21:47.880" LastActivityDate="2016-01-29T08:21:47.880" Title="What is the distribution of global photosynthesis?" Tags="|measurements|carbon-cycle|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7378" PostTypeId="1" AcceptedAnswerId="7383" CreationDate="2016-01-26T12:38:53.757" Score="3" ViewCount="184" Body="&lt;p&gt;Transgressive sills &quot;jump&quot; between bedding planes, following joints:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;_______________________&#xA;_______________________&#xA;___________/  _________&#xA;_____________/_________&#xA;_______________________&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;But can dykes do the same?&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;___________________  ___&#xA;__________________/ /___&#xA;_________________/ /____&#xA;____________/ ____/_____&#xA;___________/ /__________&#xA;__________/ /___________&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="3109" LastEditorUserId="725" LastEditDate="2016-01-27T09:06:54.440" LastActivityDate="2016-01-27T11:15:29.930" Title="Do discordants dykes ever travel concordantly (are transgressive dykes a thing)?" Tags="|geology|volcanology|structural-geology|magmatism|igneous|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7380" PostTypeId="2" ParentId="2360" CreationDate="2016-01-26T15:09:16.603" Score="3" Body="&lt;p&gt;I can't do, or won't do the math, but here is how I get around it. &#xA;Look up the saturation line at the temperature and pressure that I am concerned with on pseudo-adiabatic diagram. Then multiply the relative humidity times  the saturation rate at that temperature. It's not precise, since there are many factors that vary, and you are approximating from a paper chart, but it's a good enough estimate for my work. Hope this is helpful for those of us at the simple end of the concept. &lt;/p&gt;&#xA;" OwnerUserId="5310" LastActivityDate="2016-01-26T15:09:16.603" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7381" PostTypeId="2" ParentId="7371" CreationDate="2016-01-26T17:26:00.243" Score="10" Body="&lt;p&gt;We might have some wiggle room, or might be past the tipping point, but we do not have enough info to be sure. It depends of unknown strength of known positive feedback loops, like: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;melting permafrost releasing potent greenhouse gas methane&lt;/li&gt;&#xA;&lt;li&gt;drying permafrost bogs release CO&lt;sub&gt;2&lt;/sub&gt; or even burn&lt;/li&gt;&#xA;&lt;li&gt;warming ocean might release &lt;a href=&quot;https://en.wikipedia.org/wiki/Methane_clathrate&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Methane_clathrate&lt;/a&gt; (methane ice) - remember Deepwater Horizon?&lt;/li&gt;&#xA;&lt;li&gt;and likely more.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;What we are certain is, the more CO&lt;sub&gt;2&lt;/sub&gt; we release, the closer we will get to the tipping point, after which different climate might stabilize, close to &lt;a href=&quot;https://en.wikipedia.org/wiki/Paleocene%E2%80%93Eocene_Thermal_Maximum&quot; rel=&quot;nofollow&quot;&gt;PETM&lt;/a&gt;, the onset of which has been linked to an initial 5 °C temperature rise and extreme changes in Earth’s carbon cycle. It lasted about 170K years. Alligators in Alaska, ocean level 270 feet (90 m) higher), lots of arable land and many big cities (London, New York, Shanghai) submerged, etc. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How big human population such different planet can support? We don't know, but I am not sure we should try to find out the hard way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or another way to formulate this: &lt;strong&gt;Can Earth support intelligent life? We don't know, we are about to find out.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One solution for &lt;a href=&quot;https://en.wikipedia.org/wiki/Fermi_paradox&quot; rel=&quot;nofollow&quot;&gt;Fermi Paradox&lt;/a&gt;  (&quot;Where is everybody?&quot;) is that technological civilizations like ours destroy their environment and go extinct. &lt;/p&gt;&#xA;" OwnerUserId="5001" LastEditorUserId="725" LastEditDate="2016-01-27T09:01:13.870" LastActivityDate="2016-01-27T09:01:13.870" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7382" PostTypeId="2" ParentId="7362" CreationDate="2016-01-26T20:12:56.887" Score="4" Body="&lt;p&gt;The peak period is only one of multiple parameters that is used to describe the spectral shape of ocean waves. Most commonly used parameters are significant wave height, mean period, and dominant (peak) period. Significant wave height is proportional to the square-root of total wave energy and it tells us how much bulk wave energy is there at any given location. Mean period tells us how long are waves on average, and peak period indicates how long are the waves with maximum energy. These are just statistical parameters describing the shape of the spectrum. In reality, accurate prediction of the whole spectrum is important for wave prediction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What happens if we vary the peak wave period while keeping the total wave energy, and thus significant wave height, constant? These are some of the effects that can expect with longer peak period:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Swell propagates faster and reaches the shore sooner, as you mentioned in your question;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Because swell propagates faster, wave dissipation from swell outrunning wind will increase;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Longer waves are more dissipated due to bottom friction, i.e. longer waves will feel the bottom sooner as they propagate toward shallow water;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Longer waves induce Stokes drift that decays more slowly with depth compared to that of shorter waves, inducing stronger Lagrangian transport at depth and enhanced Langmuir circulations;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Longer waves with same wave energy are less steep, effectively decreasing the dissipation of short waves that &quot;ride&quot; on the forward faces of swell waves;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Different interaction with structures, as mentioned by Wolfgang Bangerth.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Because of the above physical processes, waves at peak period affect the evolution of the spectral shape both locally and along their propagation line.&lt;/p&gt;&#xA;" OwnerUserId="192" LastActivityDate="2016-01-26T20:12:56.887" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7383" PostTypeId="2" ParentId="7378" CreationDate="2016-01-27T09:16:09.723" Score="4" Body="&lt;p&gt;Yes, they are. It's not the sills or dykes that &quot;jump&quot;, it's the magma. Depending on the various parameters such as viscosity, stress, temperature, pressure, and local conditions and availability of joints, the magma will flow either as a sill or a dyke (or some other intrusive body).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Notice that your two sketches are basically the same thing - it's just the in one case the sill is the dominant structure whereas the dyke is more dominant in the second sketch.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The flow regime can definitely change from a &quot;dyke&quot; to a &quot;sill&quot; and vice versa. Here's a schematic diagram:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0xuxm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0xuxm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; (source: USGS)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also had a quick Internet search and came up with this great example from nature:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KNhja.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KNhja.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can read more about it at &lt;a href=&quot;http://geotripper.blogspot.com.au/2015/03/another-cool-california-roadcut-dike.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geotripper&lt;/a&gt; blog by Garry Hayes.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2016-01-27T11:15:29.930" LastActivityDate="2016-01-27T11:15:29.930" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7384" PostTypeId="1" AcceptedAnswerId="7585" CreationDate="2016-01-27T09:36:12.217" Score="6" ViewCount="283" Body="&lt;p&gt;We can see that the last glacial period &lt;a href=&quot;https://en.wikipedia.org/wiki/Last_glacial_period&quot;&gt;ended 12-10K years ago&lt;/a&gt;. Interestingly enough, this also appears to coincide with the rise of large human civilisations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: &lt;strong&gt;What caused the earth's climate to stabilise ~10 thousand years ago?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="895" LastEditorUserId="725" LastEditDate="2016-01-27T11:16:23.430" LastActivityDate="2016-02-26T05:15:12.887" Title="What caused the earth's climate to stabilise ~10 thousand years ago?" Tags="|climate|earth-history|paleoclimatology|ice-age|glaciation|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7385" PostTypeId="1" AcceptedAnswerId="7386" CreationDate="2016-01-27T13:14:59.027" Score="3" ViewCount="93" Body="&lt;p&gt;The &lt;a href=&quot;https://nex.nasa.gov/nex/projects/1349/wiki/general_data_description_and_access/&quot; rel=&quot;nofollow&quot;&gt;official data description&lt;/a&gt; of the recently updated GIMMS NDVI3g record describes the grid parameters of the dataset as follows. &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;grid-name: Geographic Lat/Lon&#xA;pixel-size: 1/12=0.0833 degrees&#xA;&#xA;size-x: 4320&#xA;size-y: 2160&#xA;&#xA;upper-left-lat: 90.0-1/24&#xA;upper-left-lon: -180.0+1/24&#xA;lower-right-lat: -90.0+1/24&#xA;lower-right-lon: 180.0-1/24&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;This means (at least to my understanding) that in x-direction, the cell size equals&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;&amp;gt; (180-1/24) * 2 / 4320&#xA;[1] 0.08331404&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;whereas in y-direction, the cell size equals&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;&amp;gt; (90-1/24) * 2 / 2160&#xA;[1] 0.08329475&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;I.e., the single grid cells are not entirely square-shaped. Am I missing something in my calculation or does the officially described pixel size of &quot;1/12=0.0833 degrees&quot; simply result from rounding effects of the manually calculated edge lengths in x- and y-direction?&lt;/p&gt;&#xA;" OwnerUserId="5322" LastActivityDate="2016-01-27T14:09:02.867" Title="GIMMS NDVI3g grid cells not entirely square-shaped?" Tags="|remote-sensing|data-formats|cartography|geospatial|vegetation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7386" PostTypeId="2" ParentId="7385" CreationDate="2016-01-27T14:09:02.867" Score="4" Body="&lt;p&gt;Your understanding is inaccurate. The shifts by $\frac{1^\circ}{24}$ are only relevant for figuring out, where the pixel centers are located and where to start when you are looking to find the right grid index for a certain point. As for the resolution, it is much simpler. We have $4320$ pixels covering $360^\circ$ in longitude direction, i.e. a resolution of $\frac{1^\circ}{12}$ and similarly for the latitudinal resolution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the square-nature of these pixels, they are only squares in lat-lon coordinates, not in terms of length on the ground.&lt;/p&gt;&#xA;" OwnerUserId="681" LastActivityDate="2016-01-27T14:09:02.867" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7387" PostTypeId="2" ParentId="7371" CreationDate="2016-01-27T19:29:29.167" Score="-5" Body="&lt;p&gt;According to satellite datasets (RSS), last year was not even close to being warmest ever. The warmest year still is 1998, and the second warmest is 2010.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is beyond me why NOAA or NASA GISS (who use NOAA's data), ignore satellite measured temperatures, which give far more accurate and complete picture of the world's global temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QrG2f.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QrG2f.png&quot; alt=&quot;RSS satellite measured global temperature anomaly&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Below is a map of the coverage of the data NOAA and NASA GISS uses. I find it hard to believe they can tell us the global temperature in sufficent accuracy to claim whether some individual year was some hundredths of degrees warmer than some other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are almost no data on the oceans, Antarctis, Africa or the north pole. Just extrapolating the little data they have over thousands of kilometers just isn't going to produce accurate enough data to detect such a small changes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This in mind, I'd rather turn to the satellites, which show nothing to be worried about.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/icCzO.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/icCzO.gif&quot; alt=&quot;global temperature coverage&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5323" LastEditorUserId="5323" LastEditDate="2016-01-27T20:38:59.270" LastActivityDate="2016-01-27T20:38:59.270" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7389" PostTypeId="1" AcceptedAnswerId="7418" CreationDate="2016-01-27T22:03:58.490" Score="13" ViewCount="2420" Body="&lt;p&gt;The Greenhouse Effect can be described semi-formally as follows:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;With no atmosphere, virtually all of the heat received by the Sun would be radiated back into space at night.  This can be seen on the moon, for example.&lt;/li&gt;&#xA;&lt;li&gt;Atmospheric gases have a &quot;greenhousivity&quot; property that traps heat and holds it in.  Some gases have more greenhousivity than others.&lt;/li&gt;&#xA;&lt;li&gt;Let the value of the weighted average of the greenhousivity values for the mixture of gases commonly known as &quot;air&quot; be arbitrarily defined as 100.&lt;/li&gt;&#xA;&lt;li&gt;There exist certain gases whose greenhousivity value is so much higher than 100 that adding even a few parts per million to our atmosphere--far below any threshold that would make the air unsafe to breathe--can raise the heat retention of our atmosphere by a non-trivial amount.  These are known as &quot;greenhouse gases&quot;.  The two best-known examples are carbon dioxide and methane.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;With this understanding, an interesting question arises.  Because the value of 100 for the greenhousivity of standard air is an average for a mixture of gases, this necessarily implies the existence of gases with a value less than 100.  &quot;Anti-greenhouse gases,&quot; if you will.  So what's stopping us from pumping a few parts per million of anti-greenhouse gases--some of which are normal parts of air, that we're already well-equipped to breathe--into the atmosphere to counteract the influence of greenhouse gases?&lt;/p&gt;&#xA;" OwnerUserId="341" LastEditorUserId="2536" LastEditDate="2017-05-28T09:54:36.830" LastActivityDate="2019-09-09T21:15:40.867" Title="Are there anti-greenhouse gases?" Tags="|climate-change|geoengineering|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7390" PostTypeId="1" CreationDate="2016-01-27T22:27:50.943" Score="9" ViewCount="1058" Body="&lt;p&gt;I am working with an algorithm for terrain correction of gravity data. I am using Nagy, 1973. However, I could not get the results I need.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, this is the problem. I have this function&#xA;&lt;a href=&quot;https://i.stack.imgur.com/gvbMP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gvbMP.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;where x,y,z are the coordinates of a prism corner.&lt;/li&gt;&#xA;&lt;li&gt;the equation 2 is the numerical method, where $S(xi) =  -1 for x&amp;lt; 0,  1 for x &amp;gt; 0$ and $0$ for $x=0$. same applies $y$&#xA;but $F(x,y,z) = 0$ when $z = 0$ &lt;/li&gt;&#xA;&lt;li&gt;The equation 3 gives the $z$ component of the gravitational attraction &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;It looks pretty simple to implement but I can't get a consitent result. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;then, I know that I have to multiply by $G$ the gravitational constant and the density of the earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have the following coordinates&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$(x1,x2) = (-500,500)$&lt;/li&gt;&#xA;&lt;li&gt;$(y1,y2) = (500,1500)$&lt;/li&gt;&#xA;&lt;li&gt;$(z1,z2) = (500,1500)$&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The earth density is $1000\ kg/m^3$. I should get a result of $2.360\ miliGals$. But I didn't. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I attach the code in python, Anyone with an answer?&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;def nagy1973(x, y, z):&#xA;from math import log, sqrt, atan&#xA;&#xA;# computes the total gravitational atraction of a rightrectangular Prism&#xA;# input x =  tuple with x1 and x2 coordinates&#xA;#       y =  tuple with y1 and y2 coordinates&#xA;#       z =  tuple with z1 and z2 coordinates&#xA;# output GravCorrect = a terrain correction for a right rectangular prims.&#xA;def Fz(a,b,c):&#xA;    # this is the numerical method for the gravitational&#xA;    # attraction over the Z component&#xA;    # input a = x&#xA;    #       b = y&#xA;    #       b = z&#xA;    # output F = GravCorrect    terrain correction&#xA;    a = abs(a)&#xA;    b = abs(b)&#xA;    c = abs(c)&#xA;    r = sqrt(a**2 + b**2 + c**2)&#xA;    r0 = sqrt(a**2 + b**2)&#xA;&#xA;    GravCorrect = a * log((b+r0)/(b+r)) + b * log((a + r0)/(a + r)) + c* atan(a*b/(c*r))&#xA;    return GravCorrect&#xA;&#xA;GravCorrAcum = 0 # this gives total z component of a prism&#xA;for k in range(1, 3):&#xA;&#xA;    for j in range(1, len(y)+1):&#xA;&#xA;        for i in range(1, len(x)+1):&#xA;&#xA;            if x[i-1] &amp;lt; 0:&#xA;                sgnX = -1&#xA;            elif x[i-1] == 0:&#xA;                sgnX = 0&#xA;            else:&#xA;                sgnX = 1&#xA;&#xA;            if y[j-1] &amp;lt; 0:&#xA;                sgnY = -1&#xA;            elif y[j-1] == 0:&#xA;                sgnY = 0&#xA;            else:&#xA;                sgnY = 1&#xA;&#xA;            sgnIJK = (-1)**(i+j+k)&#xA;&#xA;            RealSign = sgnIJK * sgnX * sgnY&#xA;&#xA;            #print(sgnIJK, sgnX, sgnY, RealSign)&#xA;&#xA;            GravCorr = Fz(x[i-1], y[j-1], z[k-1])&#xA;&#xA;            FinalFz =  RealSign * GravCorr&#xA;&#xA;            GravCorrAcum += FinalFz*6.67408e-11*1000*100000 #multiply by the gravitational constant &#xA;                                                            #density 1000 kg/m3,100000 conversion constant to miligals &#xA;                                                            # output miligals&#xA;           # print  FinalFz, GravCorrAcum&#xA;&#xA;return GravCorrAcum&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Call the function:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;x= (-500, 500)&#xA;y = (500, 1500)&#xA;z = (500, 1500)&#xA;FZ1 = nagy1973(x, y, z)&#xA;print FZ1 &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="5324" LastEditorUserId="5594" LastEditDate="2017-12-13T21:46:06.637" LastActivityDate="2017-12-13T21:46:06.637" Title="Terrain correction for gravity data using Nagy, 1973" Tags="|geophysics|geodesy|python|gravity|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7391" PostTypeId="2" ParentId="7389" CreationDate="2016-01-27T22:42:25.263" Score="10" Body="&lt;p&gt;Fundamentally your reasoning is flawed because the major composition of the atmosphere is nitrogen and oxygen.  &quot;Pumping a few parts-per-million&quot; of some other gas into the atmosphere won't do anything to the relative contribution of GHGs to global warming.  GHG's contributions will still be felt the same, regardless of the presence of any other gas.  The &quot;anti-greenhouse gas&quot; that you refer does not exist.  All gases scatter and absorb different wavelengths of light in unique ways, and this all varies by temperature. However, no gas destroys light energy.  A realistic answer is to increase clouds and aerosols, which will reflect more energy back to space before it can be absorbed by the Earth's surface.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Humans now account for the majority of greenhouse gases in our atmosphere.  Regardless if we shut off all our GHG emissions, our climate will still be warm for at least the next century.  Realistic solutions to reduce climate warming include:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;grow massive tree farms; increase algae production and forest cover.&lt;/li&gt;&#xA;&lt;li&gt;stop emission sources&lt;/li&gt;&#xA;&lt;li&gt;cover disturbed and urban surfaces (and rooftops) in reflective color/material&lt;/li&gt;&#xA;&lt;li&gt;cloud-seeding (which can also increase snow-cover)&lt;/li&gt;&#xA;&lt;li&gt;Injecting aerosols/particles into the stratosphere to mimic a major volcanic event &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2016-01-27T23:37:37.880" LastActivityDate="2016-01-27T23:37:37.880" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7392" PostTypeId="1" CreationDate="2016-01-28T04:12:22.557" Score="2" ViewCount="3864" Body="&lt;p&gt;I'm sorry if this is a stupid question. I was wondering if someone could briefly explain what the Pleniglacial age is and how it fits in with &lt;a href=&quot;http://www.ucmp.berkeley.edu/help/timeform.php&quot; rel=&quot;nofollow&quot;&gt;the geologic time scale&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, if someone could recommend a way to keep track of all of these names I would appreciate it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;" OwnerUserId="5326" LastActivityDate="2016-01-28T13:34:51.807" Title="What is the Pleniglacial age?" Tags="|geology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7393" PostTypeId="1" AcceptedAnswerId="7394" CreationDate="2016-01-28T04:26:41.587" Score="15" ViewCount="5798" Body="&lt;p&gt;I live in the northern suburbs of Johannesburg in South Africa.&#xA;I have noticed while working with synoptic weather charts in geography class that the isobars indicate that Johannesburg should have atmospheric pressure of around 1010-1020 hPa, just like most cities around the coast, even though Johannesburg is at 1500 m above sea level.&#xA;Weather service providers also indicate that Johannesburg's atmospheric pressure should be around that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What confuses me is that my weather station at home (which I have been monitoring for several years now) never seems to show pressure ratings out of 840-860 hPa.&#xA;My outdoor watch gives me the same pressures.&#xA;I am convinced that my watch cannot be broken because during my holiday in coastal Cape Town, it gave pressure readings of the expected 1020~ hPa and I can &quot;feel&quot; the higher pressure that I am not used to.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Surely both of my apparatus cannot be wrong.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there an explanation for this?&lt;/p&gt;&#xA;" OwnerUserId="5327" LastEditorUserId="-1" LastEditDate="2016-01-28T23:15:42.993" LastActivityDate="2019-10-15T06:59:33.443" Title="Why are weather service atmospheric pressures systematically different from those I measure in Johannesburg?" Tags="|meteorology|atmosphere|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7394" PostTypeId="2" ParentId="7393" CreationDate="2016-01-28T04:30:01.220" Score="22" Body="&lt;p&gt;They apply a correction to the actual barometer readings and report what the estimated pressure would be at sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically they use an imaginary column of air between the barometer and sea level and add its weight to the pressure measured at the barometer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This lets them make pressure maps instead of just almost altitude maps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/pilot_handbook/media/PHAK%20-%20Chapter%2011.pdf&quot;&gt;https://www.faa.gov/regulations_policies/handbooks_manuals/aviation/pilot_handbook/media/PHAK%20-%20Chapter%2011.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ec.gc.ca/manobs/default.asp?lang=En&amp;amp;n=4349ABDA-1&quot;&gt;https://www.ec.gc.ca/manobs/default.asp?lang=En&amp;amp;n=4349ABDA-1&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user5328" LastActivityDate="2016-01-28T04:30:01.220" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7395" PostTypeId="2" ParentId="7393" CreationDate="2016-01-28T09:47:20.677" Score="12" Body="&lt;p&gt;This is adding to Dawn's answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to check your pressure readings against those of the synoptic charts, use the equation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$P$ $=$ ${\rho}gh$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$\rho$ is the density of air&lt;/li&gt;&#xA;&lt;li&gt;$g$ is the the gravitational constant, $9.8$ $m/s^2$&lt;/li&gt;&#xA;&lt;li&gt;$h$ is the height&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The average density of air at sea level is  is $1.225$ $kg/m^3$ and the elevation of Johannesburg is $1500$ $m$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The equivalent column of air would have a pressure of&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$P$ $=$ $1.225(9.8)(1500)$ $=$ $18$ $007$ $Pa$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Divide this by $100$ to get hectopascals gives $180$ $hPa$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the synoptic chart gives a pressure of $1020$ $hPa$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then, $1020 - 180$ $=$ $840$ $hPa$&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-01-28T09:47:20.677" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7396" PostTypeId="2" ParentId="7392" CreationDate="2016-01-28T13:34:51.807" Score="4" Body="&lt;p&gt;The Pleniglacial is a stage of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Weichselian_glaciation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weichselian&lt;/a&gt; &lt;a href=&quot;https://en.wikipedia.org/wiki/Chronostratigraphy&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chronostratigraphy&lt;/a&gt; which is divided in three stubstages (early, middle and late). You can compare the absolute age to the geologic time scale.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5OEcq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5OEcq.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Data from:&#xA;Kasse, C., Huijzer, A. S., Krzyszkowski, D., Bohncke, S. J. P. and Coope, G. R. (1998), Weichselian Late Pleniglacial and Late-glacial depositional environments, Coleoptera and periglacial climatic records from central Poland (Bełchatów). J. Quaternary Sci., 13: 455–469. doi: 10.1002/(SICI)1099-1417(1998090)13:5&amp;lt;455::AID-JQS398&gt;3.0.CO;2-T)&lt;/p&gt;&#xA;" OwnerUserId="2861" LastActivityDate="2016-01-28T13:34:51.807" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7397" PostTypeId="2" ParentId="7377" CreationDate="2016-01-28T17:29:57.893" Score="3" Body="&lt;p&gt;You are perhaps looking for &lt;a href=&quot;https://en.wikipedia.org/wiki/Primary_production&quot; rel=&quot;nofollow noreferrer&quot;&gt;primary production&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is a measure for the total amount of biomass produced. Primary production is measured in two different ways, &lt;em&gt;gross primary production&lt;/em&gt;, that is simply everything produced by the photosynthesis, and &lt;em&gt;net primary production&lt;/em&gt;, that is the same, except for that the amount consumed by the plants is subtracted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The estimates are about 115 gigatons of carbon per year of net production on land, and 55 gigatons of carbon per year for the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&#xA;Roughly $\frac{2}{3}$ on land and $\frac{1}{3}$ in the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cultivated land contributes to about 9% of the net production on land.&#xA;Read more about that &lt;a href=&quot;http://www.pnas.org/content/110/25/10324.full&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Below is the annual average of the net productivity of vegetation on land and in the ocean during 2002 (from &lt;a href=&quot;http://science.nasa.gov/earth-science/oceanography/living-ocean/remote-sensing/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://science.nasa.gov/earth-science/oceanography/living-ocean/remote-sensing/&lt;/a&gt; )&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sdbsa.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sdbsa.jpg&quot; alt=&quot;2002 Net Productivity&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5333" LastEditorUserId="543" LastEditDate="2016-01-28T18:10:43.923" LastActivityDate="2016-01-28T18:10:43.923" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7398" PostTypeId="1" AcceptedAnswerId="7399" CreationDate="2016-01-28T22:20:11.097" Score="6" ViewCount="1839" Body="&lt;p&gt;Assume we have two cities A and B both at the same longitude (say $45^{0}$ E) but at different latitudes say $8^{0}$N and $90^{0}$ N. Can we get a time difference between these two cities. I raised this question because the shape of the Earth is oblate spheroid,i.e., bulges out at the equator and constricts at the poles. In 24 hours the Earth rotates once. But the circle at the equator traversed by the sun is not equal to the high latitudes because of the shape of the Earth. This difference in circle traversed by the sun makes a difference in time between the two latitudes. Am I wrong to put it that way? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To elaborate a little bit, one day is 24 hours and is the period of time during which the Earth completes one rotation with respect to the Sun. We call it a solar day. One complete rotation around the equator gives big circle (longer circumference) and around the higher latitudes makes small circle (smaller circumference). So the time it takes to complete one complete circle around the equator is not equal to the time it takes in higher latitudes. Or are they equal?&lt;/p&gt;&#xA;" OwnerUserId="4877" LastEditorUserId="28050" LastEditDate="2016-01-29T14:53:24.390" LastActivityDate="2019-09-02T04:20:28.233" Title="Is there a time difference between two points at the same longitude but at different latitudes?" Tags="|geophysics|planetary-science|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7399" PostTypeId="2" ParentId="7398" CreationDate="2016-01-29T00:01:26.837" Score="7" Body="&lt;p&gt;Earth's rotation has a fixed angular speed, therefore time is the same across the entire surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even though the tangential speed (speed of the point in the surface) is different in each place of the surface, what counts here is the angular speed (the speed of rotation). Different tangential speed compensate the distance to the rotation axis by:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(angular speed) = (tangential speed)/(distance to axis)&lt;/p&gt;&#xA;" OwnerUserId="5004" LastEditorUserId="543" LastEditDate="2016-01-29T08:18:12.287" LastActivityDate="2016-01-29T08:18:12.287" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7400" PostTypeId="1" AcceptedAnswerId="7413" CreationDate="2016-01-29T01:29:59.423" Score="7" ViewCount="2136" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3zc6E.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3zc6E.png&quot; alt=&quot;Rose diagram&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can someone comment on technical explanation of the wind rose attached? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can understand the wind is blowing between WNW &amp;amp; SSW with speed of 7-11 km/h. For frequency of 11-16 km/h its blowing from SW &amp;amp; SSW.&#xA;For frequency of 4-7 km/h its blowing between WNW &amp;amp; ESE?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this all or some info I am missing?&#xA;What do the spikes mean?&lt;/p&gt;&#xA;" OwnerUserId="5122" LastEditorUserId="725" LastEditDate="2016-01-29T08:39:11.090" LastActivityDate="2016-01-31T17:48:26.023" Title="Help interpreting a wind rose diagram" Tags="|models|wind|weather-forecasting|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7401" PostTypeId="2" ParentId="7400" CreationDate="2016-01-29T07:27:14.860" Score="8" Body="&lt;p&gt;No, you've misunderstood it. There's lots of information you're missing. Every data point is information, and you've listed a tiny proportion of them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, 4-7 km/h and 11-16 km/h aren't frequencies at all, they're wind speeds. The distance from the centre gives you the frequency.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the spike towards N means that North winds are much much more frequent than the NNW and NNE winds. There may be some protection in those directions such that the winds that would come from there, are actually getting channelled to come from the North instead. Or there's a particular time-of-day effect, or a recording artifact, or one of a dozen other explanations that only someone with more information about the site and the data collection could assess.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the fastest winds don't blow from that direction at all: they're all coming from the quadrant between S and W.&lt;/p&gt;&#xA;" OwnerUserId="100" LastActivityDate="2016-01-29T07:27:14.860" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7402" PostTypeId="1" AcceptedAnswerId="7403" CreationDate="2016-01-29T18:00:40.463" Score="4" ViewCount="402" Body="&lt;p&gt;I asked a question about solar day difference between two latitudes on the same longitude here on the Earth surface. The answer was clear due to constant angular rotation time is the same. Tangential speed is different in the two points though. Then I came up with another question here that was the reason for my previous question. Gaseous bodies like the sun have different angular rotations from the equator to the poles. Others may still argue that the Earth is rocky and solid but we have a fluid atmosphere  that can have differential rotational impact on Earth's rotation. So, my question is anyone aware of the differential angular rotation on Earth as a result of solid earth and fluid atmosphere interaction? If so, what is its latitudinal gradient? &lt;/p&gt;&#xA;" OwnerUserId="4877" LastEditorUserId="239" LastEditDate="2016-01-29T22:27:02.360" LastActivityDate="2016-01-29T22:45:50.360" Title="Is there a differential angular rotation on Earth?" Tags="|meteorology|geophysics|geodynamics|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7403" PostTypeId="2" ParentId="7402" CreationDate="2016-01-29T22:45:50.360" Score="4" Body="&lt;p&gt;The Earth's atmosphere rotates at more or less the same rate as the Earth as a whole. Note my use of &quot;more or less&quot;. That does not mean exactly the same.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The air does rotate pretty much at the same rate as the Earth near the equator. These are the doldrums. Getting stuck in the doldrums was a big problem for ships in the days when ships used sails.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Moving northward or southward, the air near the surface of the Earth tends to rotate slightly less than the solid Earth's rotation rate. These are the trade winds. Sailing ships used the trade winds to go from Europe to the western hemisphere. The coriolis effect means that the trade winds stop at about 30° north and south latitude. These are the horse latitudes, another area where the atmosphere pretty much does rotates with the Earth. Sailing ships had problems here, too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Moving even further north in the northern hemisphere / south in the southern hemisphere brings one to the region where surface winds blow predominantly from the west, so faster than the Earth's rotation rate. Sailing ships used these winds to return to Europe from the western hemisphere. Finally, even further from the equator (at roughly 60° north or south latitude), yet another transition occurs. This is the polar cell.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;So, my question is anyone aware of the differential angular rotation on Earth as a result of solid earth and fluid atmosphere interaction?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I mentioned sailing ships. People have been aware of how the winds blow locally since sailing started. People probably started sailing before they started writing. The Portuguese discovered the importance of the trade winds before Columbus sailed to the Americas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far I've only written about winds near the surface. The winds are different well above the surface. There are jet streams at the boundaries between where the trade winds and prevailing westerlies flow and at the boundaries of the polar cells.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Japanese discovered these jet streams during World War II and used this to their advantage. They launched &lt;a href=&quot;https://en.wikipedia.org/wiki/Fire_balloon&quot;&gt;fire balloons&lt;/a&gt; from near Tokyo to drop a bomb on the US about three days later. Nowadays, we use the jet streams for more peaceful purposes.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2016-01-29T22:45:50.360" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7404" PostTypeId="2" ParentId="2558" CreationDate="2016-01-30T00:51:42.577" Score="1" Body="&lt;p&gt;The easiest way to look at earthquake data that you would like in a data set you can work on (filter,plot,process,etc.) is three steps.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Get yourself a copy of Matlab&lt;/li&gt;&#xA;&lt;li&gt;Go to the iris website and download a program called IrisFetch.m (see &lt;a href=&quot;http://ds.iris.edu/ds/nodes/dmc/manuals/&quot; rel=&quot;nofollow&quot;&gt;http://ds.iris.edu/ds/nodes/dmc/manuals/&lt;/a&gt;) . &lt;/li&gt;&#xA;&lt;li&gt;Next you need a list of events and a list of stations from which to download the event, both of these can be gained simultaneously with a program from iris called Jweed. Just download both lists into a cvs file and import to Matlab and run through IrisFetch. This requires a very basic understanding of programming in Matlab but its not hard to figure out at all. Later on you will learn that you don't need Jweed at all to do this but instead can do it all through IrisFetch. Jweed is popular and easy to use though.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;If this is too complicated, you can use the web-based part of iris to look at specific earthquakes at specific stations. But I don't think you get to interact with the data this way.&lt;/p&gt;&#xA;" OwnerUserId="5343" LastEditorUserId="543" LastEditDate="2016-01-30T03:23:22.410" LastActivityDate="2016-01-30T03:23:22.410" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7405" PostTypeId="1" CreationDate="2016-01-30T03:15:02.557" Score="8" ViewCount="39802" Body="&lt;p&gt;It is said that &lt;em&gt;Earth rotates from west to east&lt;/em&gt;. I take this as &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;Earth's western hemisphere moves towards the Eastern hemisphere when seen from the frame of reference of pole star&lt;/em&gt;. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Now I can also say that,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;Earth's Eastern hemisphere moves towards the western hemisphere when seen from the frame of reference of pole star&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So can't I say then Earth rotates from east to west?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When we say Earth rotates from west to east we don't say a point on earth moves from &lt;em&gt;its&lt;/em&gt; west to &lt;em&gt;its&lt;/em&gt; east. We just say Earth moves from west to East. Now what is west and East for Earth? My knee-jerk is that Earth's west means the western hemisphere. Then it is not wrong to say Earth moves from East to west as the Eastern hemisphere always move towards the western hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;P.S: The question was originally asked at &lt;a href=&quot;https://gis.stackexchange.com/q/178685/66197&quot;&gt;https://gis.stackexchange.com/q/178685/66197&lt;/a&gt; The discussion in comments over there might be useful.&lt;/p&gt;&#xA;" OwnerUserId="5344" LastEditorUserId="-1" LastEditDate="2017-04-13T12:33:47.360" LastActivityDate="2019-01-16T14:18:50.923" Title="Why do we say Earth rotates from west to east?" Tags="|geography|earth-rotation|" AnswerCount="4" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="7406" PostTypeId="2" ParentId="2187" CreationDate="2016-01-30T03:44:18.037" Score="0" Body="&lt;p&gt;The natural variation of astrophysical cycles that affect climate (collectively known as the &lt;a href=&quot;http://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;nofollow noreferrer&quot;&gt;Milankovitch cycles&lt;/a&gt; can be seen in ice core records.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An image of the EPICA and Vostok ice cores versus age obtained from &lt;a href=&quot;http://en.wikipedia.org/wiki/Ice_age&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ice Age (Wikipedia)&lt;/a&gt;, clearly shows influence of the Malenkovitch cycles.  The most notable of which is the strong cycle that is approximately 70,000 years and is associated with geologic ice ages. In fact, the Earth is historically on average much cooler than it is now, and the retreat of glaciers has been periodic but not sustained.  We were supposed to have cooled off some time ago, but clearly we are not in a global cooling period. Many would even argue that humans started affecting the climate over 7,000 years ago when land management and fire was wielded prevalently.&lt;br&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/mw7QG.png&quot; alt=&quot;EPICA and VOSTOK Cores&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would rather not get into what a climate-change skeptic &lt;em&gt;might&lt;/em&gt; say.  However, we can use climate models to determine natural variation without anthropogenic forcings.  Below is an image of this from the IPCC AR5 Technical Summary draft which shows a full climate simulation and one without anthropogenic climate forcers.  Note that currently the climate is changing much faster than it would naturally. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QOUuB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QOUuB.png&quot; alt=&quot;Climate Model vs Historical Records&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="111" LastEditDate="2016-10-15T14:41:18.800" LastActivityDate="2016-10-15T14:41:18.800" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7407" PostTypeId="2" ParentId="4872" CreationDate="2016-01-30T04:43:01.147" Score="-2" Body="&lt;p&gt;Even if we disregard sinkholes and erosion, we must still consider the water underground.  Massive aquifers are being drained from Iran to Kansas, USA.  I see no reason why the continents might not be sinking into the sea, the deep and ancient ocean trenches filling up with silt from the continents above them.  The land is certainly increasing in desertification (&lt;a href=&quot;http://article.sapub.org/10.5923.j.ijaf.20130302.03.html&quot; rel=&quot;nofollow&quot;&gt;http://article.sapub.org/10.5923.j.ijaf.20130302.03.html&lt;/a&gt;) that causes more soil to flow into the seas, so the excess water from the aquifers is neither returning to the aquifers nor staying on the surface of the land.  So, it might be a bit tedious, but if we could calculate how much land we are losing vs. how much water is not returning to the underground aquifers, we could know whether the continents are sinking or the seas are actually rising.  I suppose we could do a census of heights above sea level and see if the average went down but we could not include places altered by construction - and that would be most places.&lt;/p&gt;&#xA;" OwnerUserId="5345" LastActivityDate="2016-01-30T04:43:01.147" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7409" PostTypeId="2" ParentId="7405" CreationDate="2016-01-30T12:33:14.813" Score="7" Body="&lt;p&gt;Imagine you can fly ignoring wind, gravitation and other forces. You are exactly on the rotation axis looking down the Earth on its North side. You'll see the Earth turning counter-clockwise. But If you look at the same but in South Hemisphere, the Earth is turning clockwise. This is just a convention and it depends on your point of view.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nevertheless, If we look at the Earth from outside in the way that the North Pole is up and South Pole is down, you are going to see West on your left hand and East on your right hand. Always, does not matter how much you rotate. It does &lt;strong&gt;not&lt;/strong&gt; depend on your point of view.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All this works as long as we set the North Pole up and West is always on its left. It is illustrtated in &lt;a href=&quot;https://goo.gl/gPKoX9&quot; rel=&quot;noreferrer&quot;&gt;this gif&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="5350" LastEditorUserId="5350" LastEditDate="2016-01-31T15:06:16.497" LastActivityDate="2016-01-31T15:06:16.497" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="7411" PostTypeId="1" CreationDate="2016-01-31T02:51:31.597" Score="6" ViewCount="169" Body="&lt;p&gt;&lt;a href=&quot;http://eospso.nasa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA's Earth Observing System&lt;/a&gt; produces many maps of air quality and land-surface variables, from instruments like MODIS, AIRS, OMI, VIIRS, etc.  Both NASA and the scientific community produce maps of the retrieved data on a daily basis, but there are often gaps (e.g.  no data) for many locations because of clouds, satellite coverage, or other limitations.  Daily retrievals are often averaged by month or season so that a complete global map (or sub-region) can be made and then presented to the public and put into publications.&lt;/p&gt;&#xA;&lt;p&gt;Some locations have very few retrievals available for a monthly average (e.g. if there is a predominant cloud mass that sticks around for a long time).  So, researchers must choose some threshold where no data is reported.  As a graduate student, I would report the average if I had at least 4 days in the month, which seemed reasonable to me at the time for some reason.  However, the number of available data points for a monthly average fluctuates so much, that the minimum number of members in the monthly average that I chose affected my temporal trendlines.&lt;/p&gt;&#xA;&lt;p&gt;What's the minimum number of days needed for satellite-derived maps of monthly averages?  I can't call 3 days of data a &amp;quot;monthly average&amp;quot; in good faith, but is 4 days enough?  For the purposes of this question, assume there is only one possible data retrieval per day per geo-location.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-02-02T03:16:24.427" Title="What's the minimum number of days needed for reporting a &quot;monthly average&quot; of daily satellite retrievals?" Tags="|land-surface|satellites|data-analysis|air-quality|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="7412" PostTypeId="2" ParentId="7405" CreationDate="2016-01-31T07:13:51.783" Score="6" Body="&lt;p&gt;The Earth rotates from west to east or counter-clockwise. You can do simple experiment. put your face towards the polar star and stretch your hands. Your head shows North (towards polar star) and your left hand points towards  west,  your right hand points towards east and your back head points towards South. The sun rises in the East - from the direction of your right hand and sets in the west - towards your left hand. Assume the sun is fixed in space because with respect to the Earth rotation speed the Sun's rotation is very small.  Hence it is the Earth which is rotating and is the reason for sunrise and sunset. If the sun rises in the east and sets in the west, then the Earth should rotate in the opposite direction from west to east (anti-clockwise).  &lt;/p&gt;&#xA;" OwnerUserId="4877" LastEditorUserId="4877" LastEditDate="2016-01-31T07:20:11.307" LastActivityDate="2016-01-31T07:20:11.307" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7413" PostTypeId="2" ParentId="7400" CreationDate="2016-01-31T17:48:26.023" Score="5" Body="&lt;p&gt;The wind rose shows quite a few things. The goal of a wind rose is to help you understand the frequency, strength, and direction the wind comes &lt;em&gt;from&lt;/em&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why the direction the wind is &lt;em&gt;from&lt;/em&gt;, and not &lt;em&gt;to&lt;/em&gt;? Well, they are often used to visualize data for building design, and there we care about resisting loads, so we use the direction the wind comes from. They are also used in meteorology: different winds bring different weather (north winds are cold in the Northern hemisphere), and so it makes sense to use &lt;em&gt;from&lt;/em&gt; there as well. Aviators care about the winds they will encounter taking off or landing, and so they want to know what they have to resist. There are many more reasons, some of which are discussed at &lt;a href=&quot;https://en.wikipedia.org/wiki/Wind_rose&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Wind_rose&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some other things to know as you look at the chart:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;This chart is based on a time series of winds at the location. &lt;/li&gt;&#xA;&lt;li&gt;The data have been placed ('binned') into wind speed ranges, and direction ranges. For example, a recorded wind speed and direction of 12.6 km/hr from 92° will be placed into the 11-16 km/hr wind speed range, and W direction range. This makes it much easier to take in the results. &lt;/li&gt;&#xA;&lt;li&gt;The different coloured lines are for the different wind speed ranges, measured in kilometers per hour. &lt;/li&gt;&#xA;&lt;li&gt;Winds are shown in small sectors of wind direction. In this plot the bins are 22.5°, which corresponds to 16 subdivisions of the compass rose.&lt;/li&gt;&#xA;&lt;li&gt;The distance from the center of the rose gives the frequency of winds in each wind direction sector; this is why the north axis has a number on it that increases from 0 to 4000; this is the number of records.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;To use the wind rose, you can start by looking at winds of a certain speed range, for example the pale green series. This is winds in the range 7-11 km/hr. Now, follow it clockwise around the plot. You see that there is a peak in winds with a speed of 7-11 km/hr to the north, another to the E, and also a lot of 7-11 km/hr winds between WNW and SSE.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could also look at a particular wind direction, for example for winds from the west. Maybe your building has a very exposed west wall? Anyway, you would see then that the most common winds are in the range 7-11 km/hr (green line), followed by 11-16 km/hr (purple), then 4-7 km/hr (red), then 0-4 km/hr (blue), and so-on. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we wanted to, we could get the relative frequency of winds in this sector by looking at the distance from the center of the plot for each line and dividing the distance for one line by the sum of all lines in that direction sector.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can also see some information about the maximum wind speed. For example, there are no winds over 22 km/hr at this location, because there is no orange line. But, there is a light blue line, which shows winds from 16-22 km/hr, so we can say that the maximum wind speed that's been see at this location is less than 22 km/hr, but more than 16 km/hr.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This wind rose is quite hard to use. Often we would plot the wind speeds as stacked bars so that you can see what is the direction from which winds come most often. This is used in wind energy, for example. See &lt;a href=&quot;https://stackoverflow.com/questions/17266780/wind-rose-with-ggplot-r&quot;&gt;https://stackoverflow.com/questions/17266780/wind-rose-with-ggplot-r&lt;/a&gt; for an example of a different way to show this data.&lt;/p&gt;&#xA;" OwnerUserId="202" LastEditorUserId="-1" LastEditDate="2017-05-23T12:41:54.877" LastActivityDate="2016-01-31T17:48:26.023" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7415" PostTypeId="2" ParentId="4948" CreationDate="2016-01-31T20:20:46.087" Score="2" Body="&lt;p&gt;The continental crust is continental crust because of its density, not the other way around.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most dense is the material, the deepest it goes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The continental crust is made up of lighter granitic rock, while deep-sea drilling reveals that the oceanic crust is basaltic in composition.&lt;/p&gt;&#xA;" OwnerUserId="5350" LastActivityDate="2016-01-31T20:20:46.087" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7416" PostTypeId="1" CreationDate="2016-02-01T00:45:08.640" Score="10" ViewCount="3743" Body="&lt;p&gt;Consider a gas centrifuge holding two different gases. After spinning for a while, the heavier gas will move to the outside, and the lighter gas will be on the inside. In other words, we have stratified the gases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why hasn't this happened in Earth's atmosphere for N$_2$ and O$_2$?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: I'm &lt;strong&gt;not&lt;/strong&gt; considering Earth a centrifuge because it's rotating. I'm comparing it to a centrifuge because there's a weight (gravity) on the gases. In this case, the oxygen should settle to the bottom, and the nitrogen above it.&lt;/p&gt;&#xA;" OwnerUserId="2733" LastEditorUserId="725" LastEditDate="2016-02-02T01:22:48.957" LastActivityDate="2020-07-15T09:19:47.600" Title="What keeps the different gases mixed in the atmosphere?" Tags="|atmosphere|atmospheric-chemistry|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7417" PostTypeId="2" ParentId="7416" CreationDate="2016-02-01T03:15:31.553" Score="15" Body="&lt;p&gt;It's because gases also diffuse. If you separate two gases of different densities by a horizontal membrane, and then slowly remove the membrane, then the interface will diffuse. You can try this with bromine and air, for example&amp;nbsp;&amp;ndash; the bromine will stay at the bottom (easily visible because it's brown) and the air will stay at the top, but the interface will be diffuse. The bromine will largely stay at the bottom because it's &lt;em&gt;significantly&lt;/em&gt; heavier than the air, but the diffusive mixing will be much stronger if the density difference is smaller&amp;nbsp;&amp;ndash; as is the case with nitrogen and oxygen, which are of course not very different in density.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While the effect above just considers mixing due to molecular diffusion, the atmosphere of course also vigorously convects due to the effects of thermal heating (and humidity differences). Both also turn over the atmosphere and mix it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, the composition of the atmosphere does change with altitude. See, for example, &lt;a href=&quot;http://wordpress.mrreid.org/2014/08/01/the-composition-of-earths-atmosphere-with-elevation/&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;. The thing is that the thickness of layer corresponding to the blurry interface between bromine and air is about as thick as the entire atmosphere, and therefore hard to distinguish from other effects (such as ionization) that change its composition with altitude.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastEditorUserId="5259" LastEditDate="2016-02-03T20:29:57.190" LastActivityDate="2016-02-03T20:29:57.190" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="7418" PostTypeId="2" ParentId="7389" CreationDate="2016-02-01T04:46:41.633" Score="7" Body="&lt;p&gt;First things first, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the value of 100 for the greenhousivity of standard air is an average&#xA;  for a mixture of gases, this necessarily implies the existence of&#xA;  gases with a value less than 100.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This isn't a good way to look at the greenhouse effect.   I mean no offense, but it's simply not accurate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get a more realistic understanding, you have to look at reflection and wavelength, and/or by looking at the Earth's &lt;a href=&quot;http://earthobservatory.nasa.gov/Features/EnergyBalance/page4.php&quot; rel=&quot;noreferrer&quot;&gt;energy balance&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of our heat comes from the sun, but a smaller share comes from the internal heat of the earth, but the internal heat from inside the earth is reasonably consistent and can be ignored for the sake of this argument.  Stored heat is also important, and that, for example, explains why the lowest sunshine day of the year (December 21) isn't the coldest day of the year, but to keep this reasonably short, lets ignore stored heat too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The heat in / heat out balance works kind of like this (from the link above):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;71% of the energy we get from the sun warms the earth, 29% is directly reflected back into space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of that 71, 59 is returned to space from the atmosphere and just 12 is returned to space from the surface.   That's the atmospheric blanket effect in a sense.  Most of the heat, in the form of infra-red light has to travel through the atmosphere to leave the earth and the greenhouse effect reflects that light, just like colored dye in water reflects light, where clear water mostly lets light pass through it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Atmospheric circulation plays a role too, so do clouds, but lets ignore that for now as well.   The greenhouse effect, caused by CO2 or other greenhouse gas, H20 or CH4  (H20 in clouds is different, that's tiny ice particles), but water vapor, which, in the air is invisible to our eyes.  They work in essentially the same way as putting colored dye in water, the colored water absorbed and reflects more light than clear water, and the sky, to infrared light, is opaque with greenhouse gas.   That Opaqueness can only be removed by reducing the amount of greenhouse gas.   It can't be removed by adding other gas, so the greenhouse effect is essentially, directly tied to the amount of greenhouse gas in the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What Greenhouse gas does is it affects the 12% and 59%, and the rate and way that heat leaves the earth.   If heat leaves the earth more slowly, the earth gradually warms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What &quot;global cooling&quot; gases do, doesn't undo what greenhouse gas does.  That's not possible, any more than it's possible to make a dye in water stop being opaque by adding another color.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Global cooling gases do exist, but they work in a different way, by affecting the 71%-29% ratio.   Volcanic gas, for example, raises the 29% of immediate reflection and that cools the earth.   Volcanic cooling however is quite temporary, lasting a few years at most, but that's basically the gist of your question, is, what reflective to visible light gases can be used to raise the 29% so that the thicker blanket of greenhouse gas is counteracted, and that's a perfectly valid question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's 3 problems.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first is, when you talk a few parts per million in the entire atmosphere, you're talking billions and billions of tons.   inserting billions and billions of tons of gas into the atmosphere is no simple task.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The 2nd problem is, atmospheric half life.   CO2 has a very long half-life in the atmosphere.   Your average CO2 molecule that enters the atmosphere takes over 100 years to recycle back either by photosynthesis or by oceanic absorption.   It stays in the atmosphere a long time.   CH4 has a much shorter half life, of just a few years, and that's the case for many gases, so if you attempt to cool the earth using a global cooling gas, you'd need to replenish it every few years (billions of tons every few years), that gets expensive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The 3rd problem is many &quot;global cooling&quot; gases are gases we don't want in the atmosphere like SO2, which creates acid rain.   I don't think anyone wants to shoot, (you might not need billions), but tens or hundreds of millions of tons of SO2 in the upper atmosphere every few years just to fight climate change.   That would be both expensive and it would cause other problems.   Freon has a slight cooling effect because it reduces Ozone, but that's even worse.   I looked but couldn't find a list of gasses that cool the earth though I've seen them in the past.  If somebody can find one, feel free to post).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other methods of increasing the 29% reflected, we could perhaps, build orbiting giant mirrors or put reflective surfaces over land or large floating disks in the ocean but none of those methods are easy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An article on some of the problems with trying to increase the earth's reflection:    &lt;a href=&quot;http://www.theguardian.com/environment/2014/nov/26/geoengineering-could-offer-solution-last-resort-climate-change&quot; rel=&quot;noreferrer&quot;&gt;http://www.theguardian.com/environment/2014/nov/26/geoengineering-could-offer-solution-last-resort-climate-change&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's not talked about as much as reducing CO2, but increasing reflection of solar energy is being explored and studied as a possible or partial solution to man made climate change.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope that wasn't too long or wordy.   I'll try to clean it up a litte.   Corrections welcome.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2016-02-01T04:46:41.633" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7419" PostTypeId="2" ParentId="7405" CreationDate="2016-02-01T09:00:00.640" Score="4" Body="&lt;p&gt;You do realize, that you can only define/name your hemispheres &lt;em&gt;after&lt;/em&gt; the directions are defined (and &lt;em&gt;how&lt;/em&gt; they are defined) in that reference system?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth from above the Northpole and it's rotation:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/QD7OO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QD7OO.png&quot; alt=&quot;[1]&quot;&gt;&lt;/a&gt;&lt;br/&gt;&#xA;For some reason, we call that &quot;East&quot; and it's opposite direction &quot;West&quot;:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/8hyKk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8hyKk.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br/&gt;&#xA;Now we can pick some arbitrary point/line to slice the Earth into 2 hemispheres and name them according to which side of the slice is in which - &lt;em&gt;previously defined&lt;/em&gt; - direction.&lt;br/&gt;&#xA;Just for fun, let's call it our &quot;prime meridian&quot;, so everybody is clear what we are taking about.&lt;br/&gt;&#xA;(In the end .. it's a sphere. It has no &lt;em&gt;that&lt;/em&gt; point to cut or &lt;em&gt;that&lt;/em&gt; 2 hemispheres.)&#xA;&lt;a href=&quot;https://i.stack.imgur.com/fJwa9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fJwa9.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br/&gt;&#xA;Now put that together in one picture:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/G1ZwI.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G1ZwI.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br/&gt;&#xA;What is the vector named the eastern hemisphere moves?&lt;br/&gt;&#xA;It is &lt;strong&gt;East&lt;/strong&gt;. Period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It doesn't matter, that at some point(s) in time the eastern hemisphere takes place, where the western hemisphere was.&lt;br/&gt;&#xA;You cannot change the naming of the direction without rendering the whole naming convention for your hemispheres (and thus all your assumptions) null and naught.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What you are trying to do is just nonsense.&lt;/p&gt;&#xA;" OwnerUserId="5351" LastActivityDate="2016-02-01T09:00:00.640" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7420" PostTypeId="1" CreationDate="2016-02-01T09:39:53.690" Score="5" ViewCount="42" Body="&lt;p&gt;In complex climate models, measurements of Earth-based thermometers are used. What is their geographic distribution - historically? Does each measurement get equal weight?&lt;/p&gt;&#xA;" OwnerUserId="5366" LastEditorUserId="5594" LastEditDate="2017-12-13T21:40:20.570" LastActivityDate="2017-12-13T21:40:20.570" Title="Distribution of thermometric devices on earth" Tags="|climate|temperature|earth-history|earth-observation|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7421" PostTypeId="2" ParentId="7411" CreationDate="2016-02-01T10:40:51.410" Score="4" Body="&lt;p&gt;&lt;strong&gt;Provide a monthly average in every grid cell, and describe how many measurements were used for each cell.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is no fixed rule for the minimum number of days for reporting a monthly average.  A reasonable threshold will depend on the geophysical quantity of interest &lt;strong&gt;y&lt;/strong&gt;, in particular on how much &lt;strong&gt;y&lt;/strong&gt; varies on short and long timescales.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If &lt;strong&gt;y&lt;/strong&gt; varies from month to month, but does not vary a lot from day to day (example: sea surface temperature), you can probably get away with reporting a monthly average even when only one or two days have cloud-free measurements.  On the other hand, if you're measuring precipitation, your signal will be relatively noisy even if you choose a threshold of 20 days.  And any threshold is going to introduce a bias, because a lack of observation is typically due to clouds.  Although you will get a bias in any case.  In other words, if you only have one day per month you see a gap and in the clouds to observe whatever you want to know, it is a pity to throw it away.  Therefore, personally I choose a minimum of 1 observation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Critically important though: when releasing the product, add a field that &lt;em&gt;tells&lt;/em&gt; the user how many days worth of measurements make up the monthly average in any given cell!  Like that, the &lt;em&gt;user&lt;/em&gt; can decide which ones to use and which ones not to use.  More broadly speaking: producers should &lt;em&gt;document&lt;/em&gt; everything they do.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For your specific examples: search for the ATBD and/or scientific papers describing the product.  Hopefully, there is a field in the level-3 product that describes the number of measurements per cell.  If the answer is not in there, write to the producers and tell them to redo the product...  You will need this information to accurately calculate a yearly average!&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2016-02-01T10:40:51.410" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7424" PostTypeId="1" CreationDate="2016-02-01T18:22:03.497" Score="10" ViewCount="2569" Body="&lt;p&gt;I understand that all plant matter releases CO&lt;sub&gt;2&lt;/sub&gt; as it decomposes and also when it burns in, for example, a forest fire. My assumption, upon which this question is based, is that the CO&lt;sub&gt;2&lt;/sub&gt; release is the same in each case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My main question is, what drives the production of all greenhouse gases in those two situations, e.g. methane in decomposition, NOx in combustion to help determine which is worse in terms of the total radiative effects of the greenhouse gases? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I appreciate the answer is likely to vary according to type of plant matter, the degree of anaerobic decomposition and the intensity of fire. Sub question: Are there any benchmarks that indicate which is worse in some specific situation or controlled trial?&lt;/p&gt;&#xA;" OwnerUserId="5375" LastEditorUserId="725" LastEditDate="2016-02-02T01:21:31.443" LastActivityDate="2017-04-17T13:26:21.190" Title="Does natural plant decomposition release more greenhouse gases than burning" Tags="|atmosphere|climate-change|co2|atmospheric-chemistry|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7425" PostTypeId="1" CreationDate="2016-02-01T18:59:17.593" Score="4" ViewCount="233" Body="&lt;p&gt;Natural gas is mostly made of methane ($\ce{CH4}$). Methane can be produced as a result of microbes eating organic matter. But can it also be naturally formed without any assistance from organic matter?  Perhaps in conditions such as those found on the early Earth?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="725" LastEditDate="2016-12-19T01:13:38.900" LastActivityDate="2017-01-03T01:50:14.020" Title="What are the natural causes for methane formation?" Tags="|geochemistry|biogeochemistry|petroleum|methane|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="7426" PostTypeId="1" CreationDate="2016-02-01T19:07:03.733" Score="3" ViewCount="56" Body="&lt;p&gt;Oil, gas and coal are produced from organic matter. But is there an estimation how much is there still under the Earth's surface?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="725" LastEditDate="2016-02-02T01:08:53.330" LastActivityDate="2016-02-02T06:39:48.463" Title="Is there an estimation how much organic matter there is still in the ground?" Tags="|geology|economic-geology|resources|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7427" PostTypeId="1" CreationDate="2016-02-01T19:40:26.513" Score="2" ViewCount="4097" Body="&lt;p&gt;Oil in the ground is found under the oceans and seas. It is made of dead fish. But from what period are those fish? I heard they are about 119 million years old. But fish exist much longer than that. So is it clear how old our oil is?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="725" LastEditDate="2016-02-02T01:08:11.593" LastActivityDate="2016-03-03T06:18:51.500" Title="What is the age of the earth's oil?" Tags="|geology|earth-history|petroleum|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7428" PostTypeId="1" CreationDate="2016-02-01T19:49:31.063" Score="2" ViewCount="2978" Body="&lt;p&gt;Some areas of oceans are about 11 km deep. Is it because continental plates were moving away because of troughs in the middle from where new rock is formed? If so, why did it become deep? If not, what are other reasons?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="725" LastEditDate="2016-02-02T01:12:42.683" LastActivityDate="2016-02-02T01:18:45.797" Title="Why are oceans so deep?" Tags="|geophysics|geology|oceanography|plate-tectonics|subduction|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7429" PostTypeId="2" ParentId="7427" CreationDate="2016-02-01T19:51:44.683" Score="8" Body="&lt;p&gt;Oil can be generated from pretty much anything organic. The oldest oil that I know of comes from a porous Eocambrian siltstone in the Sultanate of Oman. This was formed nearly 200 million years before there were any fish around.&#xA;Apart from that, oil can be formed in any of the geological eras up to the late Cenozoic.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="725" LastEditDate="2016-02-02T01:05:46.667" LastActivityDate="2016-02-02T01:05:46.667" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7430" PostTypeId="1" CreationDate="2016-02-01T20:40:31.083" Score="7" ViewCount="1504" Body="&lt;p&gt;In an other recent question is said that because of diffusion and thermal causes oxygen and nitrogen are mixed. Nevertheless oxygen is a little bit heavier than oxygen so it should be lower in the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In an other question I read:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;This is why there is a color differential with altitude; at high altitude oxygen red dominates, then oxygen green and nitrogen blue/red, then finally nitrogen blue/red when collisions prevent oxygen from emitting anything.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/105/what-causes-the-beautiful-auroras-on-the-north-and-south-magnetic-poles&quot;&gt;What causes the beautiful Auroras on the north and south magnetic poles?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my question is why is at high altitude more aurora from oxygen while concerning diffusing it shouldn't make a difference and because of oxygen is heavier it should be lower. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But in case of an aurora it is higher, so why is that? What makes all the differences in auroras?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2017-04-03T14:15:53.270" Title="Why is at high altitude more light from oxygen in the auroras while it is heavier than nitrogen?" Tags="|atmosphere|upper-atmosphere|auroras|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7431" PostTypeId="2" ParentId="7426" CreationDate="2016-02-02T00:11:36.643" Score="1" Body="&lt;p&gt;There are estimates produced my the major coal, gas and oil producing nations, but there are large error bars for some of them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wikipedia has &lt;a href=&quot;https://en.wikipedia.org/wiki/Oil_reserves&quot; rel=&quot;nofollow&quot;&gt;oil&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Natural_gas_by_country&quot; rel=&quot;nofollow&quot;&gt;gas&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Coal_by_country&quot; rel=&quot;nofollow&quot;&gt;coal&lt;/a&gt; split down by country - well worth a read of this or the &lt;a href=&quot;https://www.cia.gov/library/publications/the-world-factbook/&quot; rel=&quot;nofollow&quot;&gt;CIA World Factbook&lt;/a&gt;, especially on the description of the various categories of oil reserves (Proven and Unproven and the various estimation methods used to work out how much is actually likely to be retrievable) but in summary:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;World Coal Reserves - 909,064,000,000 tonnes&lt;/li&gt;&#xA;&lt;li&gt;World gas reserves -  175,400,000,000,000 cubic metres&lt;/li&gt;&#xA;&lt;li&gt;World oil reserves -  1,324,000,000,000 barrels&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Now these numbers may not mean very much unless aligned with production and usage rates.&lt;/p&gt;&#xA;" OwnerUserId="755" LastEditorUserId="755" LastEditDate="2016-02-02T06:39:48.463" LastActivityDate="2016-02-02T06:39:48.463" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7432" PostTypeId="2" ParentId="7428" CreationDate="2016-02-02T01:18:45.797" Score="5" Body="&lt;p&gt;The deep zones in the ocean are not where new rock is formed. The trenches are the areas where rock is &lt;em&gt;subducted&lt;/em&gt; back into the mantle. Here's a picture to visualise it:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1QqHr.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1QqHr.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;sup&gt;&lt;em&gt;&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Tectonic_plate_boundaries2.png&quot; rel=&quot;noreferrer&quot;&gt;USGS/USGov, modified by Eurico Zimbres&lt;/a&gt;&lt;/em&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;New rock is formed at mid ocean ridges (for example 12 in the image). Those are areas that are less deep than the rest of the ocean. This rocky plate sinks underneath another plate (either continental or oceanic) and by doing so &quot;pulls&quot; that plate down (for example 13 and 18 in the image). This is what causes the extreme depth of those areas.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-02-02T01:18:45.797" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7433" PostTypeId="2" ParentId="7427" CreationDate="2016-02-02T03:10:48.233" Score="2" Body="&lt;p&gt;I think that fish actually contributed very little to the oil. Oil is typically found in current or former sedimentary fans of rivers and other basins where sediments were deposited. The Gulf of Mexico off the Louisiana and Texas is a good example, as it represents the sediments transported into the ocean by the Mississippi (and whatever rivers and basins came before).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is later converted into oil is then simply the organic matter that is transported by these rivers and deposited in sediments together with sands, silts, and other inorganic matter. The latter compacts into sandstones and other reservoir rocks. The organic carbon is most likely largely from plants and bacteria, because their overall mass is so much larger than that of animals (including fish).&lt;/p&gt;&#xA;" OwnerUserId="5259" LastEditorUserId="4789" LastEditDate="2016-03-03T06:18:51.500" LastActivityDate="2016-03-03T06:18:51.500" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7434" PostTypeId="1" CreationDate="2016-02-02T08:10:53.973" Score="6" ViewCount="1590" Body="&lt;p&gt;The Wikipedia page for &lt;a href=&quot;https://en.wikipedia.org/wiki/Axial_tilt&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth's Axial tilt&lt;/a&gt; says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Earth's obliquity oscillates between 22.1 and 24.5 degrees on a&#xA;  41,000-year cycle. It is currently 23.44 degrees and decreasing.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My Questions are:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;What changes in climate pattern can be observed when obliquity is at the extremes?&lt;/li&gt;&#xA;&lt;li&gt;How extreme can the climate get if the obliquity oscillates between 20 and 30 degrees?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="5215" LastEditorUserId="5594" LastEditDate="2017-12-13T21:35:44.000" LastActivityDate="2017-12-13T21:35:44.000" Title="Axial Obliquity and Climate Change" Tags="|climate-change|axial-obliquity|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7435" PostTypeId="2" ParentId="7416" CreationDate="2016-02-02T08:23:52.320" Score="2" Body="&lt;p&gt;Diffusion is important, but much more important is the turbulent stirring from all manner of processes such as convective clouds, hurricanes, Hadley cells, frontal systems, jet streams, etc. This is more than enough to keep the atmosphere's component gasses well mixed.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-02-02T08:23:52.320" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7436" PostTypeId="1" CreationDate="2016-02-02T11:54:44.360" Score="3" ViewCount="462" Body="&lt;p&gt;Today the Earth's magnetic field is moving a little bit, but is there going to be a point where the field suddenly radically changes direction? If so, what will be the cause of that? If not, then is the field changing all the time gradually?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="2470" LastEditDate="2023-10-03T20:25:20.513" LastActivityDate="2023-10-03T20:25:20.513" Title="How probable is it that Earth's magnetic field will change 180 degrees at once?" Tags="|geophysics|geomagnetism|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="7437" PostTypeId="1" CreationDate="2016-02-02T12:28:42.317" Score="3" ViewCount="5015" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Sedimentary_rock#Biochemical_sedimentary_rocks&quot; rel=&quot;nofollow&quot;&gt;Wikipedia says&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Biochemical sedimentary rocks are created when organisms use materials dissolved in air or water to build their tissue. Examples include:&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And then lists Limestone, Coal and Chert.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm wondering whether Coral reefs, built by coral polyps, are a sedimentary rocks. They seem to fit the &quot;Biochemical&quot; category on Wikipedia.&lt;/p&gt;&#xA;" OwnerUserId="3109" LastEditorUserId="543" LastEditDate="2016-02-03T07:35:58.227" LastActivityDate="2017-11-21T13:25:49.493" Title="Are coral reefs a Biochemical Sedimentary rock?" Tags="|geology|oceanography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7439" PostTypeId="2" ParentId="7437" CreationDate="2016-02-02T17:10:30.813" Score="3" Body="&lt;p&gt;Yes, limestone indeed is &quot;biochemical&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main categories of non biochemical sediments are sandstone, mudstone, shale, conglomerate,.. if you put the Sahara for example under lithification it will become sandstone, since it consists mostly of quartz.. almost all continental sedimentary rocks are &quot;non-chemical&quot; they just vary by the components, whilst most marine sediments are biochemical, as you say..they consist mostly of carbonate and aragonite skeletons (shells in most cases) of dead animals.. that's what makes up limestone.. the main corpus of coral reef is a good example for mostly pure limestone.. The carbonate classification is based on the amount (and form) of the skeletons.. You should have a look at it, if that's interesting to you.&#xA;Coal, as you mentioned, would be another biochemical sediment but it's not only made of skeletons but the pure organic matter of dead animals, but it's genesis is rather complicated..&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to answer your question: Yes, coral reefs are biochemical sediments and very important ones, too, since they grow really fast! &#xA;As noted in your quotation: Biochemical sedimentary rocks are created when organisms use materials dissolved in air or water to build their tissue!&#xA;That's exactly what the mentioned polyps do.. You can also have a look at stromatolithes build by cyanobacteria.. that's a nice and understandable example to understand how that works.&lt;/p&gt;&#xA;" OwnerUserId="5274" LastEditorUserId="5274" LastEditDate="2016-02-02T17:17:23.097" LastActivityDate="2016-02-02T17:17:23.097" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7440" PostTypeId="1" AcceptedAnswerId="7443" CreationDate="2016-02-02T17:50:13.510" Score="2" ViewCount="304" Body="&lt;p&gt;Does anyone know of any simple means for merging (inverse distance weighting method) hourly weather files (precip, temp, etc.) from different time zones?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am creating weather data for HUC8s, and am using the 5 closest NCDC weather stations.  But some HUC8s cross over different time zones.  Has anyone figured out the easiest method for aligning weather data?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My thought is to put everything into GMT - so that 10am is 10am everywhere, and track the offset in a new column in my data.  I believe this would work, but am having trouble completely wrapping my head around it:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Focusing on a watershed that cross from CST into EST - if it was raining at 10am EST, and also raining at 9am CST (raining at the timezone division, with weather stations on either side of the timezone division), it's raining at the same time, we are just marking the 'time' differently in each location.  However, if I transformed my date/time into GMT, with a new column tracking the offset (maybe to convert it back later), it would be the same GMT time in both locations that the rain was occurring?  In effect, it is just shifting all the weather into the same time zone, and then merging based on IDW.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone have any simple solutions I am overlooking?&lt;/p&gt;&#xA;" OwnerUserId="2714" LastEditorUserId="20" LastEditDate="2016-02-04T00:23:55.290" LastActivityDate="2016-02-04T00:23:55.290" Title="How can I merge weather data from different time zones?" Tags="|meteorology|data-analysis|" AnswerCount="3" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="7441" PostTypeId="2" ParentId="7440" CreationDate="2016-02-02T20:37:13.097" Score="2" Body="&lt;p&gt;Using your example of 10 AM EST and 9 AM CST, those are both exactly the same time and another way of specifying that time is 1500 UTC or 15Z (Z being historical for GMT, for your application the difference between UTC and GMT is negligible).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you know the location of your stations then you can know their timezone.  To make inter-comparisons between stations meaningful you need to reference them all at the same time and the easiest way is to express them in UTC.  You are correct that this is just a nomenclature change but this gives all locations a common reference anywhere on earth.  All meteorological data natively uses UTC and has been since telegraph was invented and weather data was exchanged over large distances.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2016-02-02T20:37:13.097" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7442" PostTypeId="2" ParentId="7440" CreationDate="2016-02-03T01:06:08.603" Score="1" Body="&lt;p&gt;I think you have the right idea. Best to talk about UTC now; GMT is a poorly-defined historical term. &#xA;One thing to beware of when doing the conversion : daylight saving. Do not make the mistake of assuming that it happens between the same dates everywhere! &lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2016-02-03T01:06:08.603" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7443" PostTypeId="2" ParentId="7440" CreationDate="2016-02-03T04:21:41.407" Score="1" Body="&lt;p&gt;Many good data sources will come with a UTC offset column.  This is helpful for harmonizing time zones since you can simply reverse the UTC offset to make a unified UTC dataset.  If your data doesn't have the UTC offset, then you can link to it using a table like this: &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;  TZ  UTC Time&#xA;  EST   -5&#xA;  EDT   -4&#xA;  CST   -6&#xA;  CDT   -5&#xA;  MST   -7&#xA;  MDT   -6&#xA;  PST   -8&#xA;  PDT   -7&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;So for instance, if your data is in EST, simply subtract -5 from the reported time to make it UTC.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2016-02-03T05:04:09.197" LastActivityDate="2016-02-03T05:04:09.197" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7444" PostTypeId="1" CreationDate="2016-02-03T10:56:55.340" Score="6" ViewCount="765" Body="&lt;p&gt;I know ooids form in high energy water, by rolling and building layers around a nucleation site, but I don't understand what limits their size.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Tqnbt.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Tqnbt.png&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What keeps these such a regular, small size?&lt;/p&gt;&#xA;" OwnerUserId="3109" LastActivityDate="2016-02-05T19:20:26.477" Title="Why do ooids not grow larger than 0.5 mm?" Tags="|geology|limestone|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7445" PostTypeId="1" AcceptedAnswerId="7468" CreationDate="2016-02-03T15:57:04.743" Score="3" ViewCount="254" Body="&lt;p&gt;Extreme rainfall events have different intensities at different places depending on the availability of water to precipitate. Can anyone explain how do we define/determine extreme rainfall events in a particular region with an example? &lt;/p&gt;&#xA;" OwnerUserId="735" LastEditorUserId="5594" LastEditDate="2017-12-13T21:34:16.537" LastActivityDate="2017-12-13T23:16:21.920" Title="Extreme rainfall events" Tags="|meteorology|rainfall|extreme-weather|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7446" PostTypeId="1" CreationDate="2016-02-03T18:57:35.850" Score="15" ViewCount="16081" Body="&lt;p&gt;At the moment there are deep seas and high mountains. But imagine that the land elevation of the Earth is equal everywhere. How deep would the ocean be in that case?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="94" LastEditDate="2018-02-01T14:36:49.607" LastActivityDate="2019-03-01T16:31:44.200" Title="If the Earth were a smooth spheroid, how deep would the ocean be?" Tags="|geology|ocean|world-building|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7448" PostTypeId="2" ParentId="7446" CreationDate="2016-02-03T20:19:24.657" Score="19" Body="&lt;p&gt;An approximation can be obtained quite simply by dividing the volume of water in the oceans by the surface area of an &lt;a href=&quot;https://en.wikipedia.org/wiki/Reference_ellipsoid&quot; rel=&quot;noreferrer&quot;&gt;ellipsoid&lt;/a&gt; with a smooth surface representing the idealized Earth in your question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The volume of &lt;a href=&quot;http://www.wolframalpha.com/input/?i=volume+of+oceans&quot; rel=&quot;noreferrer&quot;&gt;Earth's oceans, seas and bays&lt;/a&gt; is $1.332 \times 10^9 \text{ km}^3$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://www.wolframalpha.com/input/?i=equatorial+radius+of+earth&quot; rel=&quot;noreferrer&quot;&gt;equatorial radius of Earth&lt;/a&gt; (semi-major axis of the spheroid) is $a = 6378.1 \text{ km}$. The &lt;a href=&quot;http://www.wolframalpha.com/input/?i=polar+radius+of+earth&quot; rel=&quot;noreferrer&quot;&gt;polar radius of Earth&lt;/a&gt; (semi-minor axis) is $c = 6356.8 \text{ km}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Ellipsoid#Surface_area&quot; rel=&quot;noreferrer&quot;&gt;surface area&lt;/a&gt; of the oblate ($c &amp;lt; a$) spheroid is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$S = 2 \pi a^2 \left( 1 + \frac{1 - e^2}{e}\tanh^{-1} e \right)$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $e^2 = 1 - \frac{c^2}{a^2}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which gives us $\approx 0.51 \times 10^9 \text{ km}^2$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Dividing the volume of the oceans by this results gives us $\approx 2.6 \text{ km}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Note&lt;/strong&gt;: &lt;a href=&quot;https://earthscience.stackexchange.com/q/108/5293&quot;&gt;Earth is not a sphere&lt;/a&gt;. An ellipsoid is a better &lt;a href=&quot;https://en.wikipedia.org/wiki/Figure_of_the_Earth&quot; rel=&quot;noreferrer&quot;&gt;representation of our Earth&lt;/a&gt;. Nevertheless, the answer to your question would have been approximately the same had I used a sphere instead, as suggested in the title of your question.&lt;/p&gt;&#xA;" OwnerUserId="5293" LastEditorUserId="6031" LastEditDate="2017-08-16T03:17:27.770" LastActivityDate="2017-08-16T03:17:27.770" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="7449" PostTypeId="1" AcceptedAnswerId="7454" CreationDate="2016-02-04T00:33:28.777" Score="11" ViewCount="8745" Body="&lt;p&gt;Does a particular object have the same weight on every part of Earth or does it vary?&lt;/p&gt;&#xA;" OwnerUserId="5395" LastEditorUserId="111" LastEditDate="2016-02-08T20:24:17.330" LastActivityDate="2016-02-11T02:03:48.183" Title="Does gravity differ from place to place on Earth" Tags="|geophysics|geography|gravity|" AnswerCount="4" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7450" PostTypeId="2" ParentId="7449" CreationDate="2016-02-04T01:09:33.287" Score="10" Body="&lt;p&gt;The weight that an object with a constant mass experiences on different parts of the Earth's surface will be slightly different for different locations, largely dependent on the height above sea level and the latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is due to differencies in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Gravity_of_Earth&quot;&gt;gravitational&lt;/a&gt; strength on the Earth's surface at different locations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The accelation due to gravity, $g$, on Earth varies by $0.7\%$ from $9.7639$ $m/s^2$. In Kuala Lumpa (near the equator) the gravitational accelation is $9.766$ $m/s^2$, whereas in Helsinki (nearer the North Pole) it is $9.825$ $m/s^2$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth is not a perfect sphere, there is a bulge around the equator. Because of this, the surface of the Earth, at the equitorial regions, is farther from the centre of gravity than the surface of the Earth at the poles. This reduces the effect of gravity at the equator.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the outward centrifugal force produced by Earth's rotation is larger than at polar latitudes. This counteracts the Earth's gravity to a small degree – up to a maximum of 0.3% at the Equator – and reduces the apparent downward acceleration of falling objects.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-02-04T01:09:33.287" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7451" PostTypeId="2" ParentId="7449" CreationDate="2016-02-04T02:00:06.137" Score="8" Body="&lt;p&gt;To add to the previous answer the gravity will vary locally due to the density of the rocks (or other materials) in the area. Gravity meters are used in mineral exploration to find dense rock types associated with certain ore bodies.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2016-02-04T02:00:06.137" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7452" PostTypeId="1" CreationDate="2016-02-04T02:40:55.497" Score="5" ViewCount="336" Body="&lt;p&gt;When reading about the Milankovitch cycles &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles#Orbital_shape_.28eccentricity.29&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, it says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;If the Earth were the only planet orbiting our Sun, the eccentricity of its orbit would not perceptibly vary even over a period of a million years. The Earth's eccentricity varies primarily due to interactions with the gravitational fields of Jupiter and Saturn.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;My question is, what are the relative contributions of Saturn and Jupiter to the orbital eccentricity of the Earth?  Do the Trojan Asteroids also factor into the eccentricity of our orbit?  Finally, what is the temperature change we can expect on Earth due to changes in eccentricity of Earth's orbit around the sun (e.g. the long-term climate cycle)?&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-02-07T13:18:11.817" Title="What are the relative contributions of planets to the Milankovitch Cycles?" Tags="|climate|planetary-science|milankovitch-cycles|orbit|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7453" PostTypeId="1" CreationDate="2016-02-04T04:22:03.443" Score="4" ViewCount="435" Body="&lt;p&gt;When reading about methane and its effect on climate, it is clear that its lifetime in the atmosphere is important to the global warming potential.  However, the lifetime does vary from 9 to 15 years, depending on conditions.  What are those conditions that would affect the lifetime of methane?  How does the lifetime of methane vary in the atmosphere? &lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2016-02-04T23:29:21.953" LastActivityDate="2016-03-12T03:39:43.537" Title="How does the lifetime of methane vary in the atmosphere?" Tags="|atmosphere|climate|climate-change|greenhouse-gases|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7454" PostTypeId="2" ParentId="7449" CreationDate="2016-02-04T04:36:42.857" Score="22" Body="&lt;p&gt;There is an entire field of Geophysics called &lt;a href=&quot;https://en.wikipedia.org/wiki/Gravimetry&quot; rel=&quot;noreferrer&quot;&gt;gravimetry&lt;/a&gt; dedicated to measuring the magnitude of the gravitational field. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, we should distinguish between weight (a force) and gravity (an acceleration). Gravity is the acceleration that Earth gives to objects near its surface due to the gravitational force. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The acceleration of an object near the surface of Earth is due to the combined effects of gravity and the centrifugal acceleration from the rotation of Earth. The resulting acceleration is weakest at the equator and maximum at the poles, with a difference in magnitude of about 0.5%, because the outward centrifugal force produced by rotation is larger at the equator than at the poles. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The standard gravity, $ɡ_n$ or $ɡ_0$, (the expected or mid-range value of the gravitational acceleration of an object near the surface of Earth) is 9.80665 $m/s^2$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gravimetry measures and studies gravitational anomalies: local variations in topography (e.g., mountains) and geology (rock density) that cause changes in the gravitational field. These gravitational anomalies are measured with instruments called gravimeters. Rocks with lower density, such as sedimentary rocks, result in negative anomalies. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another effect affecting gravity is altitude, as an increase in altitude will result in a change in gravity of about 0.03% per kilometer. The maximum difference in gravity is about 2 Gal (0.02 $m/s^2$) from sea level to the top of Mount Everest.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The gravity field of Earth has been measured recently with a variety of satellites (GRACE, CHAMP, GOCE). The resulting data can be used to generate global geoids such as &lt;a href=&quot;https://en.wikipedia.org/wiki/EGM96&quot; rel=&quot;noreferrer&quot;&gt;EGM96&lt;/a&gt; (&lt;a href=&quot;http://earth-info.nga.mil/GandG/wgs84/gravitymod/egm96/intpt.html&quot; rel=&quot;noreferrer&quot;&gt;geoid calculator&lt;/a&gt;). Gravitational anomalies can be extracted by calculating differences with respect to the geoid. The range of variations is of order ±300 $mGal$ (±0.003 $m/s^2$). &lt;a href=&quot;https://i.stack.imgur.com/MSOdg.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MSOdg.jpg&quot; alt=&quot;Gravity anomaly map, Chambat, 2004&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other factors have a small effect on gravity, such as the gravitational force from the Moon and the Sun that causes the tides. The fluctuations associated with these effects are of order 0.2 $mGal$ (2 $µm/s^2$).&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2016-02-04T04:36:42.857" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7455" PostTypeId="2" ParentId="7452" CreationDate="2016-02-04T04:52:32.007" Score="4" Body="&lt;p&gt;The tidal effect over time tends to circularize orbits.    It's well known that Moon is being tidally pushed away from the Earth over time (about 1.5 inches a year).  This effect is stronger when the moon is closer and weaker when the moon is farther, so there is a very gradual tidal circularizing of orbits over time, unless the orbit is highly eccentric, then you can get the reverse effect, if, when the orbiting object accelerates ahead of the tidal bulge during Perihelion that can draw it closer to the sun during that part of the orbit and that tidal effect tends to increase eccentricity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This tidal &quot;circularizing&quot; only works in 2 body systems though.  3 body systems and n-body systems are more complicated.  I can't explain the effect of Jupiter and Saturn because 3 body gravitation is too complex, but I can tell you that Trojan asteroids and the asteroid belt are not factors or, very very tiny factors because they don't have enough mass.  orbital cycles are all about the strength of the gravitational fields any synchronization of orbits.  The gravitational fields on Earth by the asteroid belt or Jupiter trojans is too tiny.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The temperature change on earth can be observed by the ice ages.   The net effect of the Milankovich cycles, if the earth was consistent would be quite small, maybe 1 degree C peak to trough.  Most of the 10 degree change globally that we see, ice age to warm period between ice ages is due to feedback mechanisms on the earth, glacier formation and ice cover increases albedo which reflects more sunlight directly back into space and colder oceans absorb more CO2 which lowers the greenhouse effect and as glaciers grow high the air over high altitude gets colder.   Changes in ocean currents may be factors too, but that's not as well understood.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Locally, the effect can be much greater than 1 degree C though, even without the feedback mechanisms.   &lt;a href=&quot;http://www.indiana.edu/~geol105/images/gaia_chapter_4/milankovitch.htm&quot; rel=&quot;nofollow&quot;&gt;Precession&lt;/a&gt; has much more significant local effects because 3.4% closer at Perihelion means 6.8% more energy, and that's significant, even if it varies,  3.4% above normal peak summer to 3.4% below normal, low winter, but that's enough to cause a significant change.   It's thought that precession is behind the &lt;a href=&quot;https://en.wikipedia.org/wiki/North_African_climate_cycles&quot; rel=&quot;nofollow&quot;&gt;Sahara desert cycle&lt;/a&gt; between forest and desert every 13,000 years or so.   Precession may be (speculation on my part), a factor in ending ice ages as well, but it doesn't seem to be a factor in starting them, as ice ages appear to begin on roughly 100,000 year cycles and before that, 40,000 year cycles.   &lt;a href=&quot;https://en.wikipedia.org/wiki/Ice_age#Major_ice_ages&quot; rel=&quot;nofollow&quot;&gt;Source&lt;/a&gt;.   There's not any good evidence that I know of for ice ages operating on 26,000 year cycles.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2016-02-07T05:14:45.350" LastActivityDate="2016-02-07T05:14:45.350" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7456" PostTypeId="2" ParentId="7056" CreationDate="2016-02-04T07:06:44.923" Score="21" Body="&lt;p&gt;I'm sorry that this answer will be unsatisfactory and, strictly spoken, off topic, but I want to give it anyway.&lt;/p&gt;&#xA;&lt;p&gt;The answer is: You can't. Don't waste your time. Your relative has developed a paranoia. Not only is this not an isolated earth science issue; it is not even an issue with science at all. Instead, she has dismissed our common everyday frame of reference wholesale. She must assume a &lt;em&gt;lot&lt;/em&gt; of things along with a flat earth:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;As you say, a massive &lt;strong&gt;conspiracy&lt;/strong&gt; dating back hundreds of years, involving governments as varied as absolute monarchies, Hitler's and Stalin's regimes and modern democracies. This conspiracy involves government fraud on a large scale, and a secret cooperation &lt;em&gt;between&lt;/em&gt; all governments in the world. This renders all of our commonly accepted news meaningless, including news about economics and politics.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;No moon landing,&lt;/strong&gt; of course. No ISS. No astronautics as we know it whatsoever. Half of NASA's employees are liars, the other half are being lied to like everybody else and duped into performing an elaborate cargo cult.&lt;/li&gt;&#xA;&lt;li&gt;Meteorology and climate models are based on the concept of a solar system with a near-spherical earth. Their predictions are therefore meaningless.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Relativity,&lt;/strong&gt; and physics in general, is wrong (light bends, the direction of gravity towards the edge of a flat earth is obviously not as it should classically be, whatever).&lt;/li&gt;&#xA;&lt;li&gt;If the earth is not a round body shaped by gravitation, all &lt;strong&gt;cosmological&lt;/strong&gt; theories about the formation of star systems, and thus cosmology as such, must be wrong. (That also follows from her rejection of the Relativity Theory.) Then she'll have a hard time with the age of earth as well as the fossil and geological record (oh, all of &lt;strong&gt;geology&lt;/strong&gt; is wrong as well!). Why don't you ask her who created the earth?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;This belief of an alternate reality behind the scenes is paranoid. It also lets other conspiracy theories latch on with ease:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Climate change&lt;/strong&gt; is not happening, or is not happening the way we are being told, or is not happening for the reasons we are being told.&lt;/li&gt;&#xA;&lt;li&gt;Ask her about &lt;strong&gt;chem trails.&lt;/strong&gt; They may be needed to adjust a few things. And since all commercial aircraft pilots are undercover government agents anyway lest they betray the fact that they actually do not cross the poles on certain intercontinental flights, they can as well produce chem trails on the side.&lt;/li&gt;&#xA;&lt;li&gt;Ask her if the lying government also keeps people intentionally sick (maybe with the chem trails!) and &lt;strong&gt;suppresses simple, cheap medicines.&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;On a more unappetizing note, because major players in the sciences and finance system are Jews, there is an overlap with classical &lt;strong&gt;anti-semitic&lt;/strong&gt; conspiracy theories (who else would secretly rule the world?).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Whatever you come up with will be countered with a new idea; you give a few examples of that pattern in your question. Occam's razor alone would do away with such complicated nonsense.&lt;sup&gt;1&lt;/sup&gt; It was sufficient to convince the catholic church, eventually.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://xkcd.com/258/&quot; rel=&quot;nofollow noreferrer&quot;&gt;xkcd illustrates this nicely:&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3bmQt.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3bmQt.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;A paranoid person is actually not really interested in science. A scientific answer is simply inadequate: It does not address the issue! (An example for an adequate answer is &amp;quot;If the earth were flat, all your horoscopes would be wrong!&amp;quot;).&lt;/p&gt;&#xA;&lt;p&gt;One possible psychological trigger for the paranoia is when one learns that long-held supposed truths are actually wrong. Developing scepticism as a response is in order, but the pathological response is to suddenly see &lt;em&gt;all of reality&lt;/em&gt; differently, like in an ambiguous picture:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tr4Wo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tr4Wo.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;Let me add that there are plenty of reasons to be sceptical, because there is so much bad science out there  -- most nutritional advice of the last 50 years is nonsense, for example, and most cancer screening did more harm than good. To me, that is an incentive to work towards better science; for others, it's a stumble which makes them see the world differently when they look up from it.&lt;/p&gt;&#xA;&lt;hr&gt;&#xA;&lt;sub&gt;&lt;sup&gt;1&lt;/sup&gt; Occam's razor is actually the answer to your question, which only makes it to a footnote in my answer. Assuming roughly spherical bodies which follow gravity's pull in free fall makes a lot of observations fit very elegantly. It is difficult to come up with a *single* (or a handful of single) irrefutable proofs; defending its alternate reality, the paranoid mind is inventing counter-arguments to any single argument. But comparing the two theories *in toto* makes the judgement irrefutable. It is, in essence, the difference between the Ptolemaic and Copernican models of the world, and the jury is not out any longer: Copernicus' model is constructed &quot;procedurally&quot; on the basis of a few basic principles. Ptolemaeus' model, by contrast, needs many arbitrary, intricate rules for the movement of celestial bodies. Occam's razor shaves all that away.&amp;mdash; This combining of many observations into a theory is how the scientific method works in practice. Single contradicting observations do in practice *not* immediately disqualify a theory, how ever much  the mathematicians among us would prefer that. This could be seen as a generalization of Truzzi's principle: Extraordinary claims need extraordinary proof.&lt;/sub&gt;&#xA;" OwnerUserId="5396" LastEditorUserId="5396" LastEditDate="2023-03-09T16:17:33.313" LastActivityDate="2023-03-09T16:17:33.313" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="7457" PostTypeId="2" ParentId="7444" CreationDate="2016-02-04T14:16:03.193" Score="4" Body="&lt;p&gt;I was unaware of a 0.5 mm maximum rule with ooid size. The Sam Boggs Jr. book on Principals of Sedimentology and Stratagraphy indicates that ooids can grow up to 2 mm. Grains larger than this are pisoids.  The size limitation may depend on how you define an ooid. To me, an ooid carbonate grain with a nucleus and concentric layers of calcite or aragonite. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The size is likely a function of the availability of calcium and carbonate ions in the water (calcite or aragonite saturation).  I think that microbial action also contributes to large grain size, but if microbes are involved, then you might call it an oncoid instead. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The similarity of ooid size is a function of similarities in the environment of deposition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Microfacies of Carbonate Rocks by Erik Flugel is a great book that discusses these features in detail.&lt;/p&gt;&#xA;" OwnerUserId="510" LastActivityDate="2016-02-04T14:16:03.193" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7458" PostTypeId="1" AcceptedAnswerId="7471" CreationDate="2016-02-04T15:36:14.967" Score="9" ViewCount="388" Body="&lt;p&gt;Whenever I'm travelling by road on a hot sunny day and I look towards the horizon, it appears as though there is puddle ahead but as I approach it, it disappears. Why does this happen?&lt;/p&gt;&#xA;" OwnerUserId="5395" LastEditorUserId="124" LastEditDate="2016-02-06T11:52:19.213" LastActivityDate="2016-02-06T11:52:19.213" Title="Why does the road appear wet on a sunny day?" Tags="|meteorology|atmosphere|land-surface|atmospheric-radiation|atmospheric-optics|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7459" PostTypeId="1" CreationDate="2016-02-04T20:05:39.337" Score="4" ViewCount="70" Body="&lt;p&gt;I'm interested in automating spatial interpolation of groundwater level measurements. I'm wondering if anyone knows a method for automatically taking into account things like dry wells, where I can't get a depth to water measurement, but where I do know that the depth to water is greater than the depth of the screened interval of the well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The interpolation would be constrained at that location so that the water table would be below the bottom of the well. In addition to saying things like &quot;&lt;em&gt;the value at $(x_1,y_1) = z_1$&lt;/em&gt;&quot; I could also specify &quot;&lt;em&gt;the value at $(x_2, y_2) &amp;lt; z_2$&lt;/em&gt;&quot; or &quot;&lt;em&gt;at $(x_3, y_3) &amp;gt; z_3$&lt;/em&gt;&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd like to know if anyone knows any interpolation algorithms that can do this, and if there are any tools out there to implement them.&lt;/p&gt;&#xA;" OwnerUserId="5394" LastEditorUserId="5594" LastEditDate="2017-12-13T21:32:49.740" LastActivityDate="2017-12-13T21:32:49.740" Title="How to integrate dry wells into groundwater level mapping automatically (inequality constraints on the interpolation)?" Tags="|geology|hydrology|water|groundwater|hydrogeology|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7462" PostTypeId="2" ParentId="7453" CreationDate="2016-02-05T05:54:35.523" Score="1" Body="&lt;p&gt;This &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_methane&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia article&lt;/a&gt;, says that the hydroxical radical is the most important sink of atmospheric methane:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In addition to being the largest known sink for atmospheric methane, this reaction is one of the most important sources of water vapor in the upper atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\ce{CH4 + ·OH -&amp;gt; ·CH3 + H2O}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;This reaction in the troposphere gives a methane lifetime of 9.6 years. Two more minor sinks are soil sinks (160 year lifetime) and stratospheric loss by reaction with ·OH, ·Cl and ·O1D in the stratosphere (120 year lifetime), giving a net lifetime of 8.4 years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;However, it goes on to say:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;increasing emissions of methane over time reduce the concentration of the hydroxyl radical in the atmosphere. With less OH˚ to react with, the lifespan of methane could also increase, resulting in greater concentrations of atmospheric methane.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-03-12T03:39:43.537" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7463" PostTypeId="1" AcceptedAnswerId="7515" CreationDate="2016-02-05T07:13:07.667" Score="5" ViewCount="1381" Body="&lt;p&gt;How can I generate a Gaussian wavelet (time domain) with a given central frequency. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I mean if I take the Fourier Transform then its spectrum should be around that given central frequency instead of zero. For example the peak of spectrum is 20Hz and its side lobes becomes nearly zero around  $20\pm 10$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I carried out a few coding exercise which I tried are here.&#xA;&lt;a href=&quot;https://stackoverflow.com/questions/35211841/gaussian-wave-generation-with-a-given-central-frequency&quot;&gt;Link&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5413" LastEditorUserId="-1" LastEditDate="2017-05-23T12:41:54.877" LastActivityDate="2016-02-16T13:38:06.393" Title="Gaussian wavelet generation with a given frequency" Tags="|seismic|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7464" PostTypeId="1" CreationDate="2016-02-05T10:55:13.653" Score="3" ViewCount="1016" Body="&lt;p&gt;I assume at the Solstice - a definite latitude would have exactly 24 hours of daylight. What latitudes (North and South) are these - they might vary a little with longitude? &lt;/p&gt;&#xA;" OwnerUserId="5416" LastEditorUserId="595" LastEditDate="2016-02-05T15:55:29.910" LastActivityDate="2021-11-09T22:22:23.550" Title="At what latitudes does daytime last exactly 24 hours once in the year?" Tags="|earth-observation|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7465" PostTypeId="2" ParentId="7463" CreationDate="2016-02-05T11:05:17.597" Score="2" Body="&lt;p&gt;If I understand the question, I don't think you can do what you want to do. The spectrum of a Gaussian time series must contain frequencies &lt;a href=&quot;https://en.wikipedia.org/wiki/DC_bias&quot; rel=&quot;nofollow noreferrer&quot;&gt;down to DC&lt;/a&gt;, i.e. very low frequencies (Python code &lt;a href=&quot;http://docs.scipy.org/doc/scipy-0.16.1/reference/generated/scipy.signal.gaussian.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;from scipy.org&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5naUK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5naUK.png&quot; alt=&quot;Spectrum of Gaussian&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A wavelet whose &lt;em&gt;spectrum&lt;/em&gt; is a Gaussian is called a &lt;a href=&quot;http://subsurfwiki.org/wiki/Ricker_wavelet&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ricker wavelet&lt;/a&gt;, or sometimes Mexican Hat wavelet. I often use this wavelet to model &lt;a href=&quot;https://en.wikipedia.org/wiki/Reflection_seismology&quot; rel=&quot;nofollow noreferrer&quot;&gt;seismic reflection&lt;/a&gt; data. It has a central frequency, and is bandlimited. As such, the wavelet oscillates around zero amplitude — it does not have a DC component:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ugW58.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ugW58.png&quot; alt=&quot;Ricker wavelet&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2016-02-05T11:05:17.597" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7466" PostTypeId="2" ParentId="7464" CreationDate="2016-02-05T11:10:39.430" Score="9" Body="&lt;p&gt;&lt;strong&gt;The latitudes today are 66°33′46.1″ N and S, the Arctic and Antarctic Circles.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By definition, north of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Arctic_Circle&quot; rel=&quot;noreferrer&quot;&gt;Arctic circle&lt;/a&gt;, and south of the Antarctic circle, everywhere gets at least one day with no sunset, which I guess is what you mean by 'exactly 24 hours of daylight'? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the linked article: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;North of the Arctic Circle, the sun is above the horizon for 24 continuous hours at least once per year (and therefore visible at midnight) and below the horizon for 24 continuous hours at least once per year (and therefore not visible at noon).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2016-02-05T18:04:32.513" LastActivityDate="2016-02-05T18:04:32.513" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7467" PostTypeId="1" CreationDate="2016-02-05T14:35:19.440" Score="4" ViewCount="1161" Body="&lt;p&gt;I have a question about a project I have for school. I have to make a topographic map of a made up island. I was wondering if the placement of the contour lines and the index lines are correct. Also if there are any mistake, can u point it out? I am not using the answers to the advantage of getting the project done, I am using to learn because we just started this in school. Thank you guys very much&lt;img src=&quot;https://i.stack.imgur.com/IyCr1.jpg&quot; alt=&quot;![Image of map so far&quot;&gt;]&lt;a href=&quot;https://i.stack.imgur.com/IyCr1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5420" LastEditorUserId="4784" LastEditDate="2016-04-21T20:52:32.303" LastActivityDate="2016-04-21T20:52:32.303" Title="Topographic Maps" Tags="|geography|topography|mapping|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="7468" PostTypeId="2" ParentId="7445" CreationDate="2016-02-05T17:05:03.610" Score="5" Body="&lt;p&gt;We define rain events in terms of the probability of reccurrence. For example, we call a certain rainfall the &quot;10-year rain event,&quot; meaning that this amount of rain would only be expected to occur once every 10 years. We usually like to have at least 30 years of data before calculating recurrence intervals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: Just because we call something the 100-year storm event does not mean that it will only occur every 100 years.  Sometimes they occur much more frequently.  Sort of like winning the lottery twice in a row when the odds of winning at all are quite low.  Unlikely, but possible.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The 100-year storm also changes with the available data.  If we were to have several &quot;100-year storm events&quot; in the span of 10 years, we might need to go back and determine a new 100-year event that takes recent data into account.  This is especially important with respect to climate change.  In Boston, the 100-year flood event is projected to occur every 2-4 years by 2050 or so.  Obviously we then need to go back and calculate what a new 100-year event is. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://water.usgs.gov/edu/qafloods.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS Q&amp;amp;A on flooding&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.neaq.org/conservation_and_research/climate_change/climate_change_in_new_england.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;NE Aquarium Climate Change page&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5421" LastEditorUserId="6298" LastEditDate="2017-12-13T23:16:21.920" LastActivityDate="2017-12-13T23:16:21.920" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7470" PostTypeId="2" ParentId="7444" CreationDate="2016-02-05T19:20:26.477" Score="3" Body="&lt;p&gt;As already noted by Inkenbrandts answer the size limitation of ooids to 2 mm seems rather arbitrary, from Richter (1983):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Though most ooids are smaller than 2 mm, it is not&#xA;  meaningful to postulate a grain size boundary between &quot;ooids&quot; and &quot;pisoids&quot; at&#xA;  a diameter of 2 mm as suggested by Choquette (1978) and Donahue (1978), based&#xA;  on older usage, because the ooids of several occurrences exceed this limit without structural and mineralogical changes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Most Phanerozoic ooids are smaller than 2 mm, but there are some Neoproterozoic ooids which are considerably larger, up to a diameter of 16 mm. This might be because the conditions on carbonate platforms were different. Controlling factors for the growth of ooids are:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Nuclei supply:&lt;/strong&gt; &#xA;The ooids stop growing as soon as they are buried, when there is a large influx of new nuclei, small ooids get buried before they are 'fully grown'&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Growth rate:&lt;/strong&gt;&#xA;This is dependent on chemical conditions, also note that the growth rate is dependent on the surface of the oid:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ \frac{\Delta m_{growth}}{t} \propto 4 \pi r^2 $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Agitation:&lt;/strong&gt;&#xA;For ooids to grow, they need to be mobile. When the velocity of the water is not sufficient to keep them moving, they stop growing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Abrasion:&lt;/strong&gt;&#xA;When the growing ooids impact each other in high enery conditions, the mass loss during each impact is dependent on their mass: &#xA;$$ \frac{\Delta m_{abrasion}}{t} \propto r^3 $$&#xA;the larger the ooids, the quicker they loose mass when colliding with others. If there was only growth rate and abrasion on could simply calculate the radius of ooids were they stop growing, but the other factors have also have to be considered.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The authors from whom I compiled the list of factors (Sumner and Grotzinger (1993) argue argue that for the growth of large ooids there must be a low nuclei supply, so that ooids have time to grow before getting buried, and the environment has to be energetic enough that large ooids still move. One reason for low nuclei supply might be that common sources for nucleation like skeletal fragments and fecal pellets were not available in proterozoic time. The second factor could be that the large ooids grew on carbonate ramps on rimmed carbonate platforms where the high energy environment is given.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Richter, D. K. (1983). Calcareous ooids: a synopsis&quot;. In: Coated grains. Springer,pp. 71-99.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sumner, D. Y. and J. P. Grotzinger (1993). Numerical modeling of ooid size&#xA;and the problem of Neoproterozoic giant ooids&quot;. In: Journal of Sedimentary&#xA;Research 63.5.&lt;/p&gt;&#xA;" OwnerUserId="2861" LastActivityDate="2016-02-05T19:20:26.477" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7471" PostTypeId="2" ParentId="7458" CreationDate="2016-02-05T19:29:17.573" Score="8" Body="&lt;p&gt;This optical illusion is due to refraction of visible light due to density gradients near the surface and the fact that the index of refraction in a medium is dependent on the density of the medium.  In an atmospheric density gradient light will bend toward the direction of increasing density.  When it is cool at the ground and warms up with height this effect bends light toward the ground and when it is hot near the ground and cools with height this bends light toward the sky.  This is particularly strong over a road surface, which can be much hotter than the surrounding land surface.  This produces a sensible heat flux that warms the air over the road and can produce exceptional temperature gradients near the surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This strong temperature gradient near the ground is also a significant density gradient and when you look through it toward the horizon you are actually seeing the sky.  Photons that would normally illuminate the surface of the road are instead refracted by the density gradient and are bent toward your eye.  This only works for specific angles determined by the actual density gradient and this is why the mirage always appears at a certain distance.  You never really get closer or further from the &quot;water&quot; and you may be able to see road surface beyond the illusion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is an image that describes the effect:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/4FzHk.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4FzHk.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sub&gt; Image licensed CC-BY by The School of Physics UNSW&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This illustrates a the effect of a near-surface density gradient that is low density (warm) at the ground and increases (gets colder) with height.  The photons from the sky that pass close to the road are refract toward the observer and you see a false image of the sky as an inferior mirage.  The other photons do not pass through the strong density gradient and are not bent and you see the true positions of the objects.  &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2016-02-05T19:29:17.573" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7475" PostTypeId="1" CreationDate="2016-02-08T10:33:13.823" Score="6" ViewCount="1964" Body="&lt;p&gt;I've read that diamonds are created at a depth of about 180 km. By volcanic activity it comes above. But did plants and trees of 300 million years ago sink so deep? Or is it possible that  inorganic carbon, what was already in the Earth, is the source of diamonds?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've heard also that there could be other exo-planets in the galaxy that are made of diamonds so it looks like it should be possible, or isn't that true?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="725" LastEditDate="2016-05-10T09:39:33.827" LastActivityDate="2019-02-15T19:00:59.530" Title="Are all natural diamonds made of organic carbon material?" Tags="|geochemistry|sedimentology|carbon-cycle|mantle|diamond|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7476" PostTypeId="2" ParentId="7475" CreationDate="2016-02-08T12:09:21.273" Score="7" Body="&lt;p&gt;Diamond isn't made of organic C at all. Organic matter would rather become oil, gas, coal or dissolve entirely.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;C itself isn't very common in earth's mantle, but subducted eclogites and peridotites can lead to the needed C-accumulation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But also meteorite impacts can lead to the genesis of so called micro-diamonds due to the very short lasting but extreme conditions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Diamond's genesis takes place in depths from 150 up to 700km and at temperatures about 1200-1400°C.&#xA;Those conditions were present in the upper mantle during the archaeum and hadeum, that's why mining takes places mainly in older crustal zones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You are right that volcanic activity brings diamond up to the crust and surface of the earth. This process is thought to take only some minutes... This is a very quick process so that the diamond crystal structure won't change back to graphite and it's also the reason many diamond deposits can be found in sediments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think that should answer your question.&#xA;I don't know about the diamond exoplanets, though I've heard of it.. I'd say the process that leads to this is pretty unclear, but perhaps someone has clearer thoughts or information on this.&lt;/p&gt;&#xA;" OwnerUserId="5274" LastActivityDate="2016-02-08T12:09:21.273" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7477" PostTypeId="2" ParentId="7475" CreationDate="2016-02-09T02:54:30.780" Score="5" Body="&lt;p&gt;Not so fast, we can't say that 'no diamond is made of organic carbon'. There are two types of diamond, based upon the relative abundance of $^{12}C$ and $^{13}C$ isotopes. The 'lighter' carbon (relatively $^{13}C$ depleted) are thought to arise from crustal carbon-bearing rocks, possibly including some organic carbon, that was subducted into the mantle, recrystallised at great depth and ultra high pressure, and subsequently brought to the surface, either in kimberlites or in eclogites (as in the small eclogite diamonds around Malmo in Norway). These are the 'eclogite diamonds'. There are also 'heavy carbon' diamonds which are primordial in origin, in which the carbon never left the mantle until spewed up, also in kimberlites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;BTW, the deepest known origin for diamonds is under Brazil, from a depth of 800 km, but Lew is right in that the majority of diamonds are from lesser depths, if you can regard &gt;150 km as a 'lesser depth'.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="543" LastEditDate="2016-02-10T06:09:37.597" LastActivityDate="2016-02-10T06:09:37.597" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7478" PostTypeId="2" ParentId="7475" CreationDate="2016-02-09T11:05:59.737" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;But did plants and trees of 300 million years ago sink so deep?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;300 million years ago (Carboniferous) was a time when large amount of organic carbon was buried to a depth of several kilometres and formed large beds of coal. The pressure and temperature was only moderate (which is why you have coal and not diamonds).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Diamonds form at depths of hundreds of kilometres, and the source of the carbon can be any carbon. Inorganic carbon that was just there in the mantle, or organic carbon that came from any time in the Earth's history, not necessarily from the Carboniferous. So how do you get organic material hundreds of kilometres deep? The answer is subduction. I recommend you view this short video that does a terrific job in explaining of some of this stuff works:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.youtube.com/watch?v=6wJBOk9xjto&quot; rel=&quot;nofollow&quot;&gt;http://www.youtube.com/watch?v=6wJBOk9xjto&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;there could be other exo-planets in the galaxy that are made of&#xA;  diamonds...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not quite. Not &quot;made of diamonds&quot;. Just planets that have a lot of carbon. In our Earth and the other rocky planets in our solar system there is a lot of oxygen. When you take oxygen and bond it with other elements (silicon, magnesium, iron, aluminium, etc) you end up having rocks. What would happen if a planet would have more carbon than oxygen? In that case, it would be carbon bonding to the elements, not oxygen. You would have rocks made out of &lt;em&gt;carbides&lt;/em&gt;, instead of rocks composed of &lt;em&gt;oxides&lt;/em&gt;. You probably know carbides: these are usually very strong materials and they are used in industry whenever you need to do hard mechanical stuff.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyway, what would happen if you had more carbon than needed to bond with everything else? In that case you would have free carbon that in certain depths in that specific planet would be just in the right condition to form diamond. But this diamond will most likely be mixed together with all of the other carbides so I'm not sure if you will have huge blocks of pure diamond. But who knows?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some more reading &lt;a href=&quot;http://www.refinery29.uk/diamonds-are-forever-science&quot; rel=&quot;nofollow&quot;&gt;in this article&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2016-04-09T04:41:38.837" LastActivityDate="2016-04-09T04:41:38.837" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7479" PostTypeId="1" AcceptedAnswerId="7483" CreationDate="2016-02-09T15:38:55.403" Score="5" ViewCount="214" Body="&lt;p&gt;There are many papers that talk about the air quality at ground-level in cities, observed by air quality monitors.  Some monitors are located above the building(not actually on the ground). For example, my lab's equipment was located on the 5th floor of the building (~ 15m).   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My questions are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;em&gt;Is it appropriate to represent air quality using measurement data on a building roof?&lt;/em&gt;      &lt;/li&gt;&#xA;&lt;li&gt;&lt;em&gt;What's the difference between air quality on the ground &amp;amp; the roof? And what matters?&lt;/em&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="543" LastEditDate="2016-02-10T04:14:00.637" LastActivityDate="2016-02-10T04:15:35.527" Title="Why are &quot;ground level&quot; air quality monitors really on rooftops?" Tags="|atmosphere|atmosphere-modelling|air-pollution|air-quality|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7480" PostTypeId="1" AcceptedAnswerId="7482" CreationDate="2016-02-09T18:40:31.990" Score="10" ViewCount="5959" Body="&lt;p&gt;What is the cause of rainbows? Do they appear due to rainfall or any other natural phenomenon. What makes it form a semi-circle in the atmosphere and its colours?&lt;/p&gt;&#xA;" OwnerUserId="5395" LastEditorUserId="2470" LastEditDate="2018-02-24T02:45:05.667" LastActivityDate="2023-03-07T18:05:19.293" Title="What causes a rainbow, its colours and its shape?" Tags="|meteorology|atmosphere|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7481" PostTypeId="2" ParentId="2442" CreationDate="2016-02-09T23:20:15.877" Score="1" Body="&lt;p&gt;In ECMWF data, wind direction and wind speed are collected from observation separately. Then based on a well known transformation the wind vectors, u and v are calculated. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Their documentation: &lt;a href=&quot;http://www.ecmwf.int/sites/default/files/elibrary/2015/9208-part-i-observation-processing.pdf&quot; rel=&quot;nofollow&quot;&gt;http://www.ecmwf.int/sites/default/files/elibrary/2015/9208-part-i-observation-processing.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can focus on this part in their documentation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot; **Wind.**There are four wind variables: wind direction(DDD), wind force(FFF),u and v components. For each of these variables the first thing which is done is to get a local copy of it together with its related parameters from an ODB supplied array (GETSETE).Once a variable is made available locally a check is made to ensure that the vertical coordinate is pressure; if instead of pressure a flight level is supplied it is converted into pressure by assuming a standard ICAO atmosphere(Z2PICAO). If the variable in question is either u or v, then DDD and FFF are converted into u and v wind components. Furthermore, for each of the four variables appropriate observation error statistics are assigned (ERRSTAT, FINOERR). Also, if any flags are set at this stage an appropriate word in the local copy is updated (PPVAFL). Finally, an updated local copy of an observed quantity and its related parameters are returned back into the ODB (AIREPBE).&quot;*&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once wind speed and direction are obtained calculations are made to get the two components of wind u and v. &#xA;e.g. &#xA;    $$u = -FFF sin(DDD \frac{\pi}{180})$$&#xA;    $$v = -FFF cos(DDD \frac{\pi}{180})$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In calculating wind power, we need wind speed and not wind direction. If we are given u,v components of wind, we can calculate wind speed as &#xA;$$ U = \sqrt{u^{2} + v^{2}}$$.&#xA;Then, the power density,&#xA;   $$ P = \frac{1}{2}\rho A U^{3}$$&#xA;To sum up when we calculate wind power, what we need is the speed and not the direction. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This may not answer your question but I hope it may give some hint about it!&lt;/p&gt;&#xA;" OwnerUserId="4877" LastActivityDate="2016-02-09T23:20:15.877" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="7482" PostTypeId="2" ParentId="7480" CreationDate="2016-02-10T00:42:01.573" Score="14" Body="&lt;p&gt;&lt;b&gt;Short answer:&lt;/b&gt; A rainbow is formed when light enters a drop of water or an ice crystal and gets refracted and reflected back into an observer's eye.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;b&gt;Longer Answer:&lt;/b&gt; Light travels at different velocities depending on the media involved; it travels slower through water than it does through air, for instance. As light enters a raindrop or ice crystal, it first gets refracted. However, not all the frequencies of light get refracted at the same angle. The colors with the shorter wavelengths (e.g. blue, indigo, and violet) get refracted less than the longer wavelengths (red). This spreads the colors out just like passing through a prism. The light then gets reflected off of the back of the raindrop, gets refracted again as it passes out of the raindrop, and travels to the observer's eye.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason it is circular is because the light that got refracted and reflected back to the observer, does so at a specific range of angles, 40 to 42 degrees.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to see a rainbow, the sun (or other light source) must be directly behind the observer. A straight line is formed from the light source, the observers eyes, and the center of the rainbow. All rainbows are actually circles. We usually see it as an arc because the earth intercepts the circle. (BTW, because of this, no two people, even standing shoulder to shoulder, can see the same exact rainbow. Each rainbow is being created by different raindrops.) If you're ever in an airplane passing over a cloud with the sun above you (as opposed to near the horizon), you may see a complete rainbow. It's pretty awesome. &lt;br&gt;&lt;br&gt; Here's an illustration:&lt;br&gt;&lt;a href=&quot;https://i.stack.imgur.com/0Ooxh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0Ooxh.jpg&quot; alt=&quot;from: https://strongphysics.wikispaces.com/ch29_egtk&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2959" LastEditorUserId="2959" LastEditDate="2019-03-14T21:13:40.690" LastActivityDate="2019-03-14T21:13:40.690" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="7483" PostTypeId="2" ParentId="7479" CreationDate="2016-02-10T04:03:19.070" Score="4" Body="&lt;p&gt;In order to put your question in perspective, you need to consider atmospheric mixing and the size of the system you are curious about.  The troposphere is several kilometers thick and the mixed layer of atmosphere above the ground can occupy a significant fraction of the troposphere.  Granted, during cold events, the temperature of the air can be so cold that the lack of convective motion creates a very shallow (e.g. 10s of meters) mixing layer.  Though, 15 meters above the ground will virtually always be within the mixed layer near the ground, despite cold weather events.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some people do measure air quality at the ground level, but it is generally done in the context of studying biogenic emissions (e.g. soil emissions or below-canopy tree emissions).  However, those are special field studies, which have different objectives than typical air quality monitor sites.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Typical air quality monitor sites are relatively sparse, and even large cities have just a few monitors.  Generally, monitors are located in such a way that they are observing well mixed air, so that it represents air quality in the region.  It is imperative that you put your air quality monitor high enough above the ground so that it isn't being directly influenced by emission sources (e.g. your neighbors wood stove, or a car's tailpipe).  Otherwise, if you put the monitor literally on the ground, you will often be observing much more variance, with higher peaks that represent that specific location only.  See &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7310/what-principles-do-we-consider-when-selecting-an-air-pollution-monitor-location?rq=1&quot;&gt;this post&lt;/a&gt; for more info on how monitor locations are selected.  You can also see &lt;a href=&quot;http://www3.epa.gov/ttnamti1/files/ambient/pm25/qa/QA-Handbook-Vol-II.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this EPA handbook&lt;/a&gt; on siting monitors which notes:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IZ4gK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IZ4gK.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2016-02-10T04:15:35.527" LastActivityDate="2016-02-10T04:15:35.527" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7484" PostTypeId="1" CreationDate="2016-02-10T05:36:35.823" Score="2" ViewCount="261" Body="&lt;p&gt;Crystals of sugar form in hot saturated sugar solution as it cools down, due to excess sugar molecules not fitting in the solution and precipitating as crystals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a similar situation, if we have a region where temperatures are well below zero, still water should freeze. But in rivers, water doesn't freeze, because it's flowing. Do ice crystals form in such super-cold water?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(P.S. If you know any applicable tags, please add them.)&lt;/p&gt;&#xA;" OwnerUserId="5439" LastEditorUserId="56" LastEditDate="2016-02-11T00:18:29.050" LastActivityDate="2016-02-11T00:21:31.000" Title="Do ice crystals form in running super-cold water?" Tags="|water|rivers|ice|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7485" PostTypeId="1" AcceptedAnswerId="7487" CreationDate="2016-02-10T07:01:59.887" Score="7" ViewCount="5840" Body="&lt;p&gt;I am a Math student and don't know about longitude and latitude. This question was asked in CSIR-NET Mathematics. Please help me to solve it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Two points $A$ and $B$ on the surface of the Earth have the following latitude and longitude co-ordinates:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;A:&lt;/strong&gt; $30^\circ $ N , $ 45^\circ$ E&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;B:&lt;/strong&gt; $30^\circ $ N , $ 135^\circ$ W&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If $R$ is the radius of the Earth, what is the length of the shortest path from $A$ and $B$?&lt;/p&gt;&#xA;" OwnerUserId="5441" LastEditorUserId="192" LastEditDate="2016-02-10T18:24:32.767" LastActivityDate="2023-07-21T23:42:31.157" Title="What is the shortest path between two points on Earth's surface?" Tags="|geography|homework|geometry|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7486" PostTypeId="2" ParentId="7484" CreationDate="2016-02-10T07:39:45.403" Score="1" Body="&lt;p&gt;A snippet from the linked question:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Fred says:&lt;/p&gt;&#xA;&lt;p&gt;Also, while water is flowing its potential energy is constantly being converted to heat energy that resists freezing on the molecular level and subsequent crystallization.&lt;/p&gt;&#xA;&lt;p&gt;For flowing water to freeze, the temperature would have to be exceptionally cold&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="5439" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-02-10T07:39:45.403" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7487" PostTypeId="2" ParentId="7485" CreationDate="2016-02-10T07:44:04.150" Score="15" Body="&lt;p&gt;If you don't want to do the calculation yourself, you can use an online calculator like the one provided by &lt;a href=&quot;http://www.nhc.noaa.gov/gccalc.shtml&quot; rel=&quot;nofollow&quot;&gt;NOAA&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alternatively, if you do want to do the calculation yourself you can use the &lt;a href=&quot;http://www.movable-type.co.uk/scripts/latlong.html&quot; rel=&quot;nofollow&quot;&gt;haversine&lt;/a&gt; formula. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This uses the ‘haversine’ formula to calculate the great-circle distance between two points – that is, the shortest distance over the earth’s surface – giving an ‘as-the-crow-flies’ distance between the points (ignoring any hills they fly over, of course!).&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;$$a = \sin^2\left(\frac{\Delta\phi}{2}\right) + \cos \phi_1 ⋅ \cos \phi_2 ⋅ \sin^2\left(\frac{\Delta\lambda}{2}\right)$$&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;$$c = 2 ⋅ \text{atan2}( \sqrt a, \sqrt {1−a} )$$&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;$$d = R ⋅ c$$ &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;where $\phi$ is latitude, $\lambda$ is longitude, $R$ is earth’s radius (mean radius = 6,371km)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="5510" LastEditDate="2016-02-22T19:32:41.733" LastActivityDate="2016-02-22T19:32:41.733" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7488" PostTypeId="2" ParentId="7485" CreationDate="2016-02-10T15:25:28.570" Score="11" Body="&lt;p&gt;45E is directly opposite 135W.&#xA;It's therefore obvious (hopefully) that the shortest path is straight over the North pole (which is at 90 degrees North). The path takes us round 120 degrees of the Earth's circumference, or 1/3rd of it.&lt;/p&gt;&#xA;" OwnerUserId="5444" LastActivityDate="2016-02-10T15:25:28.570" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7489" PostTypeId="2" ParentId="7484" CreationDate="2016-02-10T19:50:06.157" Score="1" Body="&lt;p&gt;Rivers can freeze, but only on the surface. The water still flows below the ice. When it is colder, the ice layer can become thicker.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The kinetic energy of the moving water in rivers delays this freezing. So when water is more calm it freezes more easily.&lt;/p&gt;&#xA;" OwnerUserId="5004" LastEditorUserId="56" LastEditDate="2016-02-11T00:21:31.000" LastActivityDate="2016-02-11T00:21:31.000" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7490" PostTypeId="2" ParentId="7436" CreationDate="2016-02-10T20:07:31.127" Score="-1" Body="&lt;p&gt;Magnetic field exist because of the hot liquid in the external core of Earth moves, that movement of charged particles produces the magnetism.&#xA;Therefore, the magnetic field can't change at once, it only can change slowly with variations of these inner flows.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I &quot;suppose&quot; that earthquakes might produce small changes in the magnetic field, because seismic waves travel through the Earth core and mantle.&lt;/p&gt;&#xA;" OwnerUserId="5004" LastActivityDate="2016-02-10T20:07:31.127" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7491" PostTypeId="2" ParentId="7436" CreationDate="2016-02-11T00:14:49.660" Score="5" Body="&lt;p&gt;The magnetic north pole (and presumably the south pole) &lt;a href=&quot;http://news.nationalgeographic.com/news/2005/12/1215_051215_north_pole.html&quot; rel=&quot;noreferrer&quot;&gt;currently moves around 40km/year&lt;/a&gt;, although within a year it loops around, may travel much further than that forwards and backwards. Here is a map of the movement from the past century and a half (&lt;a href=&quot;http://science.howstuffworks.com/environmental/earth/geophysics/question782.htm&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;)&#xA;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Qjlzn.jpg&quot; alt=&quot;Movement of the pole over the last 170 years&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, during a magnetic reversal, the pole may move &lt;a href=&quot;http://scitechdaily.com/magnetic-field-flip-occur-short-period-time/&quot; rel=&quot;noreferrer&quot;&gt;up to 10 times faster than that&lt;/a&gt;, over a period of less than 100 years. Here's a map showing the relative movements (the numbers are thousands of years ago (kya)) (&lt;a href=&quot;http://scitechdaily.com/magnetic-field-flip-occur-short-period-time/&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/hPhKV.jpg&quot; alt=&quot;Magnetic field reversal 786kya&quot;&gt;]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason for reversals aren't very well understood (according to the previous link), and I'm in no way an expert in the field, but just for some fun speculation, I would wonder whether reversals might be related to &lt;a href=&quot;https://www.youtube.com/watch?v=1n-HMSCDYtM&quot; rel=&quot;noreferrer&quot;&gt;this phenomenon&lt;/a&gt;. Obviously a liquid outer core is going to operate differently from a screwdriver, but the two systems both appear to be exhibiting a bistable rotation while floating in space.&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2016-02-11T00:14:49.660" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7492" PostTypeId="2" ParentId="7449" CreationDate="2016-02-11T02:03:48.183" Score="2" Body="&lt;p&gt;Just for completeness changes in the groundwater saturation at a location can have a small effect on the gravity. Filling the pores in unsaturated sediments with water due to increased recharge from precipitation, irrigation, etc. increases the bulk density and thus the gravity. &lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2016-02-11T02:03:48.183" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7494" PostTypeId="1" CreationDate="2016-02-11T10:19:02.077" Score="2" ViewCount="47" Body="&lt;p&gt;By using a gyroscope the curvature of space-time made by the earth was measured.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that gravity is not exactly the same everywhere on the earth because of density of the mass beneath it. Probably above the mountains gravity is a bit higher. Due to variation of matter in the earth there would be other differences.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But were the results of this experiment according to what was already known or did it give new information about the earth?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="5594" LastEditDate="2017-12-13T21:29:26.730" LastActivityDate="2017-12-13T21:29:26.730" Title="Were the results of the gravity probe B according to what was expected?" Tags="|geology|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7495" PostTypeId="1" CreationDate="2016-02-11T14:57:51.037" Score="2" ViewCount="262" Body="&lt;p&gt;In fields like economics, people tend to think that catastrophic events like droughts, floods, desertification, landslides, soil erosion etc. are events which are linked to global climate change and global $\ce{CO2}$ emissions or they think these events could be exogeneous events (they argue that floods come from the massive rainfalls which are due to whole climate change problem or they think that droughts are mainly caused by the average increase of global temperature).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In some sense, I agree with these arguments but my intuition is that events like droughts, floods and desertification are events which are also due to local activities, such as deforestation or loss of wetlands.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I explain this intuition in more detail. When we cut down trees, this reduces the land's ability to absorb water from rainfall and this directly increases the frequency and severity of floods. I know that deforestation in Indonesia contributes to the whole climate change problem but &lt;strong&gt;&lt;em&gt;are there not any local impacts of this deforestation in Indonesia directly concerning droughts and floods on this region?&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/nclimate/journal/v4/n8/full/nclimate2277.html&quot; rel=&quot;nofollow&quot;&gt;Morgano et al. (2014)&lt;/a&gt; shows that there exists a massive deforestation in Indonesia. So, in this case, does the risk of having more floods, desertification and droughts increase directly in Indonesia or around this region?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this a legitimate idea or are there any academic papers which link the frequency of catastrophic events like droughts, floods and desertification to local activities, like deforestation, &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I make the same reasoning for the drought problem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This link shows how drought frequency in Sub Saharan Africa, South Asia and Latin America has increased between 1990-2010 relatively to periods 1950-1990.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.researchgate.net/figure/258971172_fig5_Figure-2-Drought-frequency-top-total-drought-severity-centre-and-total-drought&quot; rel=&quot;nofollow&quot;&gt;https://www.researchgate.net/figure/258971172_fig5_Figure-2-Drought-frequency-top-total-drought-severity-centre-and-total-drought&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Source for graphics : Spinoni et al. World drought frequency, duration, and severity for 1951-2010-International Journal of Climatology)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of FAO reports and other academic papers point out the deforestation and inappropriate use of water resources in South Asia and Sub Saharan Africa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this case, can we attribute the increase of frequency and severity of droughts in this region (and other possible events in this region) due to the bad use of this natural capital ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I really appreciate if there are some references for the local impacts of inappropriate use of natural capital.&lt;/p&gt;&#xA;" OwnerUserId="2827" LastEditorUserId="2570" LastEditDate="2016-05-23T23:33:39.993" LastActivityDate="2016-05-23T23:33:39.993" Title="How about local impacts of deforestation on droughts and floods?" Tags="|climate-change|deforestation|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7496" PostTypeId="1" AcceptedAnswerId="7498" CreationDate="2016-02-11T17:23:33.320" Score="2" ViewCount="636" Body="&lt;p&gt;I heard of the aurora borealis in North America and I've also seen the picture which made me to wonder that what causes the aurora borealis and does it have any advantages or disadvantages? &lt;/p&gt;&#xA;" OwnerUserId="5450" LastActivityDate="2016-02-11T18:20:07.117" Title="What causes the aurora borealis" Tags="|meteorology|atmosphere|" AnswerCount="1" CommentCount="1" ClosedDate="2016-02-12T04:07:07.580" ContentLicense="CC BY-SA 3.0" />
  <row Id="7498" PostTypeId="2" ParentId="7496" CreationDate="2016-02-11T18:20:07.117" Score="3" Body="&lt;p&gt;When charged particles from the sun strike air molecules in Earth's magnetic field, they cause those molecules' atoms to become excited. The molecules give off light as they calm down.                         At the center of our solar system lies the sun, the yellow star that sustains life on our planet. The sun's many magnetic fields distort and twist as our parent star rotates on its axis. When these fields become knotted together, they burst and create so-called sunspots. Usually, these sunspots occur in pairs; the largest can be several times the size of Earth's diameter.                                                                       At the center of the sun, the temperature is 27 million degrees Fahrenheit (15 million degrees Celsius). As the temperature on its surface rises and falls, the sun boils and bubbles. Particles escape from the star from the sunspot regionson the surface, hurtling particles of plasma, known as solar wind, into space. It takes these winds around 40 hours to reach Earth. When they do, they can cause the dramatic displays known as the aurora borealis.&lt;/p&gt;&#xA;" OwnerUserId="5395" LastActivityDate="2016-02-11T18:20:07.117" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7499" PostTypeId="2" ParentId="7480" CreationDate="2016-02-11T19:06:17.110" Score="3" Body="&lt;p&gt;A rainbow requires water droplets to be floating in the air. That’s why we see them right after it rains. The Sun must be behind you and the clouds cleared away from the Sun for the rainbow to appear.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A full rainbow is actually a complete circle, but from the ground we see only part of it. From an airplane, in the right conditions, one can see an entire circular rainbow.&#xA;Why the colors?&#xA;Sunlight is made up of many wavelengths—or colors—of light. Some of those wavelengths get bent more than others when the light enters the water droplet. Violet (the shortest wavelength of visible light) bends the most, red (the longest wavelength of visible light) bends the least. So when the light exits the water droplet, it is separated into all its wavelengths. The light reflecting back to you, the observer with the Sunlight coming from behind you, from the water droplets will appear separated into all the colors of the rainbow! Violet will be on the bottom and red on the top.&lt;/p&gt;&#xA;" OwnerUserId="5450" LastActivityDate="2016-02-11T19:06:17.110" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7501" PostTypeId="1" CreationDate="2016-02-12T02:51:00.370" Score="6" ViewCount="108" Body="&lt;p&gt;I've completed part A of the question below.&lt;/p&gt;&#xA;&#xA;&lt;hr /&gt;&#xA;&#xA;&lt;h3&gt;Dating fluvial terraces with $^{10}\rm{Be}$&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;One way to determine the age of an alluvial deposit is to collect a series of samples from a range of depths, from the surface down to a few meters, and analyze the cosmogenic nuclide concentration. The expectation is to find an exponential-like decline in concentration with depth, with an asymptotic value that reflects the inherited concentration. Suppose you sample an alluvial deposit on a mesa surface near Boulder and find the values that are shown in Table 1.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;10Be C      26AL C     Depth (m)&#xA;4.29E+06    2.62E+07     0.0&#xA;2.44E+06    1.64E+07    -0.5&#xA;1.88E+06    1.24E+07    -0.9&#xA;1.49E+06    9.80E+06    -1.3&#xA;1.27E+06    8.32E+06    -1.7&#xA;1.12E+06    6.89E+06    -2.5&#xA;9.99E+05    6.46E+06    -3.1&#xA;&#xA;C units (atoms/gram*year)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;A&lt;/strong&gt; Use a spreadsheet (or if you prefer, a script in Python, Matlab, etc.) to make a plot that shows the $^{10}\rm{Be}$ and $^{26}\rm{Al}$ concentrations as a function of depth. Make depth your y-axis, and have the values increase downwards.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;B&lt;/strong&gt; Make an initial guess about (1) how old the terrace is, and (2) how much of the Beryllium concentration is inherited from when the sediment was first deposited (the exact numbers you use in your guess don’t matter, since you will change them). Then use your spreadsheet to calculate the expected $^{10}\rm{Be}$ concentration that each sample should have if it had the inheritance and age that you have specified.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;C&lt;/strong&gt; Quantify the error in your guess by calculating, for each sample, the root-mean square error: (i) take the difference between the sample age and your guess, (ii) square it (to make the number positive no matter which way you’re off), (iii) take the square root, (iv) take the average.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;D&lt;/strong&gt; Now, iteratively adjust (1) your guess at the age and (2) your guess at the inheritance, until you find a pair of values that come as close as you feel you can reasonably get.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;E&lt;/strong&gt; In your paper, present and describe a graph of the sample data that also shows your best-guess curve. Discuss this “best fit” estimate of the age of the terrace. What is the root-mean square error? Can you think of a procedure that would be more systematic than trial-and-error guessing?&lt;/p&gt;&#xA;" OwnerUserId="5454" LastEditorUserId="28050" LastEditDate="2016-02-12T13:11:24.110" LastActivityDate="2016-02-12T13:11:24.110" Title="Dating fluvial terraces with $^{10}\rm{Be}$" Tags="|geology|homework|geomorphology|dating|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7502" PostTypeId="1" CreationDate="2016-02-12T20:00:55.427" Score="11" ViewCount="30871" Body="&lt;p&gt;All gas molecules have the capability to absorb radiation energy. $\rm{CO}_2$ has much less capability to absorb radiation energy, comparing with water vapor.&#xA;In Earth's atmosphere currently $\rm{CO}_2$ constitutes only about 0.04% (400 parts per million) of the atmosphere. On average, about 2 to 3% of the molecules in the air are water vapor molecules. In the air the water content is about 50 times higher than $\rm{CO}_2$.&#xA;So it seems that $\rm{CO}_2$ content increase in the air should not have any measurable contribution to global warming.&#xA;Is there any experiment to prove that $\rm{CO}_2$ with the atmosphere concentration can have greenhouse effect?&lt;/p&gt;&#xA;" OwnerUserId="5456" LastEditorUserId="5456" LastEditDate="2016-02-15T11:42:50.297" LastActivityDate="2017-09-15T16:34:38.933" Title="Is there any experiment to prove that CO2 with the atmosphere concentration can have greenhouse effect?" Tags="|climate-change|carbon|water-vapour|greenhouse-gases|" AnswerCount="7" CommentCount="16" ContentLicense="CC BY-SA 3.0" />
  <row Id="7503" PostTypeId="2" ParentId="7434" CreationDate="2016-02-13T00:32:16.627" Score="0" Body="&lt;p&gt;Generally speaking, the tilt in Earth's rotational axis is the very reason for the seasons, especially the monsoon climate in the lower latitudes. A stronger tilt causes a higher contrast in these seasons as the Sun's zenith will oscillate stronger throughout the year. Imagine a earth without any tilt. Then the Sun's zenith will always remain over the equator.&lt;/p&gt;&#xA;" OwnerUserId="5459" LastEditorUserId="2470" LastEditDate="2016-02-13T00:41:06.047" LastActivityDate="2016-02-13T00:41:06.047" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7504" PostTypeId="2" ParentId="7502" CreationDate="2016-02-13T03:01:10.240" Score="8" Body="&lt;p&gt;The short answer to your question really is just this: &lt;em&gt;Yes, CO2 causes global warming.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are many resources out there on the internet that explain this in about as much detail as you can tolerate, and whatever we could answer here does not come close to what others have already collected. I would suggest you start at &lt;a href=&quot;https://en.wikipedia.org/wiki/Global_warming&quot;&gt;the wikipedia page on global warming&lt;/a&gt; (and in particular the section on &lt;a href=&quot;https://en.wikipedia.org/wiki/Global_warming#Greenhouse_gases&quot;&gt;greenhouse gases&lt;/a&gt;, as well as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Greenhouse_gas&quot;&gt;wikipedia page on greenhouse gases&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2016-02-13T03:01:10.240" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="7505" PostTypeId="2" ParentId="7502" CreationDate="2016-02-13T16:41:25.260" Score="42" Body="&lt;p&gt;Your question about water vapour is quite a common one among people learning about the greenhouse effect. Once you discover the relevant proportions of water vapour and CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere, it's perhaps natural to assume that the CO&lt;sub&gt;2&lt;/sub&gt; can't be playing a major role. In reality it doesn't work like this, for at least a couple of reasons. First, let's look at what the 98% actually means in practice.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;It's not just about the concentration&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The concentration of a gas in the atmosphere isn't the only thing that determines its warming potential -- otherwise nitrogen, at 78% concentration, would be the most important greenhouse gas. Each gas has a different radiation absorption spectrum, and a different warming potential. So despite its much greater prevalence in the atmosphere, water vapour &lt;a href=&quot;http://www.realclimate.org/index.php/archives/2005/04/water-vapour-feedback-or-forcing/&quot; rel=&quot;noreferrer&quot;&gt;only has about twice as much long-wave absorption potential as CO&lt;sub&gt;2&lt;/sub&gt;&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At this point, you may be thinking ‘but twice as much is &lt;em&gt;still&lt;/em&gt; a lot more, so the CO&lt;sub&gt;2&lt;/sub&gt; can't be significant!’. But there's another non-obvious factor here, which has to do with the difference between feedbacks and forcings.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Forcings versus feedbacks&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;In the climate system, CO&lt;sub&gt;2&lt;/sub&gt; concentration is a &lt;em&gt;forcing&lt;/em&gt;, whereas the water vapour concentration is a &lt;em&gt;feedback&lt;/em&gt;. To illustrate the difference, here's a crude analogy:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Suppose that I'm trying to lose weight, but I'm reluctant to reduce the 300 grams of delicious chocolate cake that I eat every day. Having read that the human body is around 80% water by weight, I conclude that the cake can't be a problem: after all, I drink 2 kg of water per day, so it would make more sense to reduce that! So I cut down to 1 kg of water per day and maintain my cake intake. Several weeks later, I'm surprised to find that I haven't lost any weight! What's happened? It turns out that the human body regulates its water content, so reducing my intake just reduced my output. Fat storage isn't regulated in the same way, so the cake keeps piling up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's a similar story with CO&lt;sub&gt;2&lt;/sub&gt; and water vapour: CO&lt;sub&gt;2&lt;/sub&gt; concentration in the atmosphere actually changes for a long time (decades to centures) when we release more gas. Water vapour is, in effect, self-regulating. If we could wave a magic wand and instantaneously remove all the water vapour from the atmosphere, here's what would happen:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LSh2S.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LSh2S.jpg&quot; alt=&quot;water removal experiment&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;a href=&quot;http://www.realclimate.org/index.php/archives/2005/04/water-vapour-feedback-or-forcing/&quot; rel=&quot;noreferrer&quot;&gt;(source)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Within 50 days, the water vapour is back to  within 1% of where it would have been without our intervention.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, if the water vapour concentration isn't controlled by input, what is it controlled by? Temperature. The warmer the atmosphere is, the more water vapour it can hold. This means that when the temperature goes up due to increased CO&lt;sub&gt;2&lt;/sub&gt;, the water vapour content also increases, which further intensifies the greenhouse effect. It's acting as a positive feedback.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since you're not the first person to ask this question (by a long way), there are already some good resources online specifically addressing the different roles of water vapour and CO&lt;sub&gt;2&lt;/sub&gt; in global warming.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://www.yaleclimateconnections.org/2008/02/common-climate-misconceptions-the-water-vapor-feedback-2/&quot; rel=&quot;noreferrer&quot;&gt;&quot;Common Climate Misconceptions: The Water Vapor Feedback&quot;&lt;/a&gt; is a 2008 piece in the Yale Climate Connections series saying more or less what I've said above, but in more detail and without the cake analogy.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://www.realclimate.org/index.php/archives/2005/04/water-vapour-feedback-or-forcing/&quot; rel=&quot;noreferrer&quot;&gt;&quot;Water vapour: feedback or forcing?&quot;&lt;/a&gt; is a great 2005 essay by Gavin Schmidt explaining the role of water vapour in climate change.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.skepticalscience.com/water-vapor-greenhouse-gas.htm&quot; rel=&quot;noreferrer&quot;&gt;&quot;Explaining how the water vapor greenhouse effect works&quot;&lt;/a&gt; is a brief Skeptical Science piece mainly focusing on the positive feedback effect.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h2&gt;Laboratory measurements of CO&lt;sub&gt;2&lt;/sub&gt; absorption&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;You seem to be particularly interested in laboratory experiments on&#xA;carbon dioxide absorption. As an excellent starting point, I can&#xA;recommend the (currently) 26 publications in AGW Observer's list of &#xA;&lt;a href=&quot;https://agwobserver.wordpress.com/2009/09/25/papers-on-laboratory-measurements-of-co2-absorption-properties/&quot; rel=&quot;noreferrer&quot;&gt;papers on laboratory measurements of CO2 absorption properties&lt;/a&gt;. If you're really keen to see experimental confirmation that CO&lt;sub&gt;2&lt;/sub&gt; can still absorb radiation even at atmospheric concentrations, you could take a look at (for example) Taylor and Yates (1957), Yates and Taylor (1960), or Streete (1968), all of which clearly demonstrate that CO&lt;sub&gt;2&lt;/sub&gt; absorption bands are present in normal atmospheric air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an aside: personally I find find that the numerous spectroscopic observations of the whole atmospheric column -- from satellites or ground stations -- provide a more compelling demonstration of the greenhouse effect. After all, the atmosphere isn't a homogeneous bottle of gas that can be faithfully scaled down into a lab sample. But your question and subsequent comments indicate that you're not interested in measurements of the atmospheric column itself, so here I'm just concentrating on ground-level experiments which demonstrate the long-wave absorption properties of CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Answers to comments&lt;/h2&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If there is a such positive feedback exist without other negative feed backs, the earth will get warmer without co2 contribution.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I think you might be a little confused about the definition of a feedback here. As I've tried to explain above, the term ‘feedback’ means that the water vapour content is determined by other factors &lt;em&gt;within&lt;/em&gt; the climate system. It can amplify the effects of forcings, but it can't in itself ‘push’ the system one way or the other. So you can't have a positive feedback without some kind of forcing: the forcing is precisely the input which the feedback is ‘feeding back’ into the system, in this case via the global temperature increase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To understand the difference, it might be helpful to think about another form of feedback familiar to a lot of people -- &lt;a href=&quot;https://youtu.be/6C_zO_zguUQ?t=17s&quot; rel=&quot;noreferrer&quot;&gt;audio feedback through an electric guitar and amplifier system&lt;/a&gt;. As you can see in the linked video, there's no sound until the guitarist plays a chord. But once he does play a chord, the guitar pickup itself detects the amplified sound and feeds it &lt;em&gt;back&lt;/em&gt; into the amplifier, creating a loop which sustains the sound indefinitely. You can think of the initial chord as analogous to the CO&lt;sub&gt;2&lt;/sub&gt; input, and the feedback loop as analogous to the water vapour effect: the audio feedback, like the water vapour feedback, doesn't do anything until it's got an initial input from some other source.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;All co2 released from fossil fuel was in the atmosphere during the dinosaurs time. If co2 release from all fossil fuel, it will restore the dinosaurs time atmosphere status. ... you can not deny that those co2 was in the atmosphere in earth history and earth animals and plants flourished&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This doesn't really have much to do with your original question! If you want to ask about this, please go ahead and post a new question; StackExchange &lt;a href=&quot;https://meta.stackexchange.com/a/92110&quot;&gt;isn't a discussion site&lt;/a&gt;, and we try to keep each question focused on a single topic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With this in mind, I'll just give a very brief answer here. Your formulation is a little inaccurate: the age of the dinosaurs spans at least 135 million years, there was a lot of carbon burial before it started, and all the carbon currently in the ground wasn't in the atmosphere at the same time. However, it is true that the Earth has seen higher CO&lt;sub&gt;2&lt;/sub&gt; levels than at present, and that much of that excess carbon is now locked up in fossil fuels. So what would happen if we put a lot of that carbon back in the atmosphere and tried to recreate the high-CO2 atmosphere that, say, &lt;em&gt;T. rex&lt;/em&gt; breathed in the Late Cretaceous? Back then, the Earth was a lot warmer, with little or no ice at the poles. One of the biggest effects of re-releasing all that carbon would be the melting of our current polar ice sheets, raising sea levels by some tens of metres. The problem is not that the Earth will become completely uninhabitable by any life form whatsoever (although many current species will go extinct). The problem is that a lot of species, &lt;strong&gt;including&lt;/strong&gt; &lt;strong&gt;&lt;em&gt;Homo sapiens&lt;/em&gt;&lt;/strong&gt;, are poorly prepared for a climate change of this magnitude. Ten percent of the world's human population and 8% of its urban land area is in low-elevation coastal zones, and would be completely submerged by a 10-metre sea-level rise -- which is still far less than the sea levels seen during the age of the dinosaurs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sea-level rise is just one effect among many, but for now I'll leave it at this since (as I mentioned above) this isn't related to your original question.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If a person cut his water intake in half, he will get sick before he can get fatter.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is a little peripheral to the question, I think :-). If you don't like the analogy you can ignore it: it's not essential to the explanation. However, just to reassure you: the EPA &lt;em&gt;Exposure Factors Handbook&lt;/em&gt; (2011 edition) gives a mean value of 1,043 ml for the daily drinking water intake of an adult in the US. Thus, I don't think that restricting one's water intake to 1 kg per day, as in my thought experiment, would necessarily cause sickness.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;h2&gt;References&lt;/h2&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Streete, J. L. (1968). Infrared measurements of atmospheric transmission at sea level. Applied optics, 7(8), 1545-1549.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Taylor, J. H., &amp;amp; Yates, H. W. (1957). Atmospheric transmission in the infrared. JOSA, 47(3), 223-226.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Yates, H. W., &amp;amp; Taylor, J. H. (1960). Infrared transmission of the atmosphere (No. NRL-5453). Naval Research Lab, Washington DC.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="94" LastEditorUserId="-1" LastEditDate="2017-03-20T10:32:31.770" LastActivityDate="2016-02-17T15:56:42.453" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="7506" PostTypeId="1" CreationDate="2016-02-14T05:06:39.627" Score="2" ViewCount="38" Body="&lt;p&gt;Is it possible to receive data from a Geosig VE-53 to a PCI data acquisition (serial port) connected to PC and without using a recorder? &lt;/p&gt;&#xA;" OwnerUserId="5462" LastEditorUserId="725" LastEditDate="2016-02-14T10:43:04.230" LastActivityDate="2016-02-14T10:43:04.230" Title="Earthquake data acquisition Geosig VE-53" Tags="|seismology|earthquakes|data-analysis|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7507" PostTypeId="1" CreationDate="2016-02-14T09:17:17.497" Score="5" ViewCount="90" Body="&lt;p&gt;How useful are physics based models when considering circulations at synoptic scales? Are they useful? Can we not make predictions, observe trends based on data alone? I am studying A.E.Gill's model on tropical circulation and this thought often occurs to me due to the approximations made in the model.&lt;/p&gt;&#xA;" OwnerUserId="5378" LastActivityDate="2018-10-12T22:04:36.847" Title="Physics based circulation models" Tags="|atmosphere-modelling|atmospheric-circulation|synoptic|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7508" PostTypeId="1" CreationDate="2016-02-14T12:35:23.980" Score="2" ViewCount="2548" Body="&lt;p&gt;I was wondering why are coal and petroleum being both fossil fuels are found at different places i.e. coal at land and petroleum at sea.&lt;/p&gt;&#xA;" OwnerUserId="5463" LastEditorUserId="6129" LastEditDate="2020-05-08T06:13:08.917" LastActivityDate="2020-05-08T06:13:08.917" Title="Petroleum and coal formation" Tags="|petroleum|fossil-fuel|coal|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7509" PostTypeId="2" ParentId="7508" CreationDate="2016-02-14T13:22:22.437" Score="8" Body="&lt;p&gt;Coal, oil and gas can be found anywhere on Earth: on land and on sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Japanese once mined coal from beneath the sea floor, using &lt;a href=&quot;https://en.wikipedia.org/wiki/Hashima_Island&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hashima Island&lt;/a&gt; as the base of operations. The island is only 6.3 ha in size.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://www.jstor.org/stable/41372889?seq=1#page_scan_tab_contents&quot; rel=&quot;nofollow noreferrer&quot;&gt;British also mined coal from under the sea&lt;/a&gt;, in the &lt;a href=&quot;http://www.maden.org.tr/resimler/ekler/2b15c75c0c389b4_ek.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;north east of England&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for oil, the following picture from &lt;a href=&quot;http://pubs.usgs.gov/fs/fs-062-03/&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS&lt;/a&gt; shows the current oil-prone petroleum basins in the world, outside of the USA.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/G2sia.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G2sia.png&quot; alt=&quot;World Oil Fields&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following oil basins are all on land:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Russia&lt;/li&gt;&#xA;&lt;li&gt;Arabia, Kuwait, Iraq and north Africa&lt;/li&gt;&#xA;&lt;li&gt;China&lt;/li&gt;&#xA;&lt;li&gt;Eastern Europe&lt;/li&gt;&#xA;&lt;li&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Oil_sands&quot; rel=&quot;nofollow noreferrer&quot;&gt;Canadian oil sands&lt;/a&gt; and other plays in the province of Alberta, Canada&lt;/li&gt;&#xA;&lt;li&gt;Colombia&lt;/li&gt;&#xA;&lt;li&gt;The oil fields of &lt;a href=&quot;https://en.wikipedia.org/wiki/East_Texas_Oil_Field&quot; rel=&quot;nofollow noreferrer&quot;&gt;east Texas&lt;/a&gt;, USA&lt;/li&gt;&#xA;&lt;li&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Pennsylvania_oil_rush&quot; rel=&quot;nofollow noreferrer&quot;&gt;former oil fields in Pennsylvania&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;When oil &amp;amp; coal deposits formed they each had different mechanisms of &lt;a href=&quot;http://f03.classes.colgate.edu/fsem037-oil/formation_of_oil.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;formation&lt;/a&gt;. Coal is derived of plant material that once lived on land, died, formed peat, which then got buried.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oil however, owes its origins to algae &amp;amp; plankton that lived in the oceans. When they died they sank to the bottom of the ocean and deposited in waters with very low, if any oxygen. Eventually, these deposits were covered by sediments. If the deposit was subject to a significant amount of geothermal heating gas deposits formed, otherwise oil deposits formed. Movements of the Earth's crust then repositioned some of the deposits which is why some coal is now under the sea and some oil is now on land.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="28050" LastEditDate="2016-02-14T15:44:57.650" LastActivityDate="2016-02-14T15:44:57.650" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7511" PostTypeId="2" ParentId="7502" CreationDate="2016-02-15T13:49:25.083" Score="11" Body="&lt;p&gt;Experiments don't necessarily prove things, &lt;em&gt;per se&lt;/em&gt;; and in particular, a single experiment tends not to prove anything - at the very least, replication of the experiment is required. Experiments provide contributory evidence. Confidence in a hypothesis can come about from a combination of theory, lab experiments and natural experiments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Our knowledge about the greenhouse effect comes about from a combination of lab experiment and natural experiment, complemented by various theories that are testable and have tested successfully.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first experimenters and theorists worked in the nineteenth and early-to-mid twentieth century: Joseph Fourier, John Tyndall, Svante Arrhenius, Guy Callendar. Perhaps most notably, it's &lt;a href=&quot;https://archive.org/details/contributionsto01tyndgoog&quot; rel=&quot;noreferrer&quot;&gt;John Tyndall's work&lt;/a&gt; with a thermopile, measuring the absorption spectrum of various gases, that were the first to most directly address your question. More recently, advances in spectrographic analysis mean that lab experiments can identify which parts of the electromagnetic spectrum are absorbed by $\ce{CO2}$, and by how much. Crucially, there are bands of very high absorption by $\ce{CO2}$, at frequencies where $\ce{H2O}$ has much lower absorption:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.ces.fau.edu/nasa/module-2/how-greenhouse-effect-works.php&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yIb3f.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, we have lab experiments that demonstrate that CO2 with atmospheric concentrations do contribute to the greenhouse effect. These experiments go back almost two hundred years, and the more research we do, the greater corroboration we find, from both lab experiments, natural experiments, and wider theories in physics and chemistry.&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="100" LastEditDate="2016-02-15T16:04:02.170" LastActivityDate="2016-02-15T16:04:02.170" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="7512" PostTypeId="2" ParentId="7502" CreationDate="2016-02-15T19:40:33.577" Score="6" Body="&lt;p&gt;&lt;strong&gt;The Faint Young Sun Paradox - how greenhouse gases can keep a planet warm:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the Earth formed 4.5 billion years ago the Sun was around 30% less luminous than it is today and it has increased steadily since, based on well established models of solar evolution. Simple energy balance models of the Earth show that, with a similar atmosphere to today, the mean global temperature would have been well below freezing. However, there are sedimentary rocks from at least 3.8 billion years ago which show clear signs of being lain down in liquid water. Therefore, something must have kept the planet warm in its early history. The culprit is $\ce{CO_2}$, and probably $\ce{CH_4}$ as well, which may have been present in levels at least 100 times as high as today, and possible far higher. Another example of the power of the greenhouse effect of $\ce{CO2}$ is Venus, which has an atmosphere 50 times as dense as that on Earth and composed of 97% $\ce{CO2}$. Surface temperatures reach 500°C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The Quaternary Record - non-linear responses to solar forcing:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This figure shows the $\delta ^{18}\text{O}$ record from benthic foraminfera preserved in deep sea sediment cores from the past 1.2 million years alongside the July 21st insolation at N65 (northern hemisphere summer) as calculated from celestial mechanics. $\delta ^{18}\text{O}$ from benthic forams is a good proxy for ice sheet volume (high $\delta ^{18}\text{O}$ = high ice volume, and vice versa) and so what we see is that ice sheet volume generally correlates well with solar forcing.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/PbMPl.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PbMPl.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;However&lt;/em&gt;, look closer and there are problems. Although deglaciations correspond will with increases in summer insolation, the magnitude of the increase is not always well correlated to the scale of the deglaciation. In particular, the stage V termination shows a huge deglaciation (one of the largest in the Quaternary) in response to a very small solar forcing. Clearly some other factors must amplify the forcing signal to produce the changes observed. Secondly, we observe that in the later part of the Quaternary the major period of glacial-interglacial oscillation is about 100,000 years. The solar forcing consists of three components, eccentricity (100,000 and 400,000 year periods), obliquity (41,000 year period) and precession (21,000 year period). If you look at each of the forcings separately, the eccentricity forcing is by far the weakest and yet it is dominant in the $\delta ^{18}\text{O}$ record. Although it is not obvious from this chart (the earlier half of the Quaternary is not shown) there is a switch at around 1 million years ago from a dominant glaciation period of 40,000 years to 100,000 years and yet there is no change in the forcing pattern. Additionally, note that in the present day insolation is low and yet the world is warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The next figure shows atmospheric $\mathrm{CO_2}$ and $\mathrm{CH_4}$ records as measured from Antarctic ice cores from the past 800,000 years, alongside $\delta \text{D}$ records which are a good proxy for temperature. There is a &lt;em&gt;very&lt;/em&gt; good correlation between $\mathrm{CO_2}$ levels and temperature, and a good correlation with $\mathrm{CH_4}$ levels, particularly for large temperature rises.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FWtFQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FWtFQ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;But haven't we been here before?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The figure below shows the $\delta ^{18}\text{O}$ record from the last 65 million years. The temperature scale on the right only applies to an ice-free world (i.e. before ~30 million years ago [I won't go into the reasons why unless you are particularly interested]) but the general trend is still evident. There has been gradual cooling since the Eocene, with some variability along the way. $\ce{CO2}$ levels in the Eocene were at least 1000ppmv (compared to 280ppmv for pre-industrial levels and 400ppmv for the present day) and this is reflected in the temperatures and lack of ice.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/tOxW2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tOxW2.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might then say, what is the problem with putting all this $\ce{CO2}$ into the atmosphere? The key issue is not the magnitude of the change, it is the rate of the change. The changes in $\ce{CO2}$ concentration in the Eocene took place over millions of years, giving most life time to evolve to cope with the changing temperatures. However, we are putting large volumes of $\ce{CO2}$ into the atmosphere in the space of a few hundred years and this is having drastically different effects. The closest analogue we have to our current situation is the Palaeocene-Eocene Thermal Maximum. If you look closely at the graph you will see a spike in the $\delta ^{18}\text{O}$ record at 55 million years ago. This corresponds to a rapid warming of around 5-8°C and subsequent cooling back to previous temperatures over a period of around 200,000 years. Although it is not shown on this graph, there is a corresponding dip in the $\delta ^{13}\text{C}$ record, indicating a large injection of carbon into the atmosphere, in the form of $\ce{CO2}$ and $\ce{CH4}$, which caused a rapid rise in temperatures due to the greenhouse effect. This is very similar to what we are doing today, only we are doing it at least 20 or so times faster.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Conclusions:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Solar forcing is a factor that affects global temperatures, particularly in the recent past, but the responses are highly non-linear, and the forcing alone is not enough the explain the observed changes. $\ce{CO2}$ and $\ce{CH4}$ levels in the atmosphere are closely correlated with global temperatures and abrupt changes in these levels has caused abrupt changes in temperature in the past. The amount of water vapour in the atmosphere is a function of temperature (refer to @Pont's excellent answer) and so is not a relevant forcing for increasing temperatures (indeed clouds may have a slight negative feedback effect because they have a very high albedo).&lt;/p&gt;&#xA;" OwnerUserId="2570" LastEditorUserId="2570" LastEditDate="2016-02-16T11:07:33.290" LastActivityDate="2016-02-16T11:07:33.290" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="7513" PostTypeId="1" CreationDate="2016-02-15T21:23:59.040" Score="4" ViewCount="141" Body="&lt;p&gt;I have done the &lt;a href=&quot;https://www.youtube.com/watch?v=E8AvfXar9zs&quot; rel=&quot;nofollow&quot;&gt;cloud in a bottle experiment (Youtube video)&lt;/a&gt; with a thermometer probe in the bottle to show the temperature increase and decrease.  I am interested in the nature of the changes as the cloud nuclei get covered with water and then as the water evaporates (almost instantly) with the increased pressure as you squeeze the bottle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For those unfamiliar with the subject,  evaporation of a cloud droplet absorbs energy and the formation of a droplet releases energy. I find it interesting (and counter intuitive) that when you release pressure,  cloud droplets form (meaning that the droplets themselves are releasing  energy).  Why are they releasing  energy in a system that is already going to a lower energy state?  Seen as a part of the system,  as a speck of smoke at the start of the pressure drop,  they have no energy to begin with!    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would also like to see a theory about this. Where the things that happen are related to how catalysts work.  Smoke is a catalyst in this case.  And where the condensation nuclei are acting almost like &quot;buffers&quot; in acid base theory.  A buffer in acid base acts as a proton donor or proton acceptor   to reduce pH fluctuations. Maybe the condensation nuclei can be seen as doing the same thing to reduce temp, and pressure changes in the cloud? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, anyways, a cloud droplet forms around a condensation nucleus.  Energy is released, while water vapor is absorbed from the gas around the nucleus.   As the droplet falls into lower humidity air,  it releases droplet water as water vapor with absorption of energy. On the one hand,  more water vapor is more volume, but on the other hand,  the lower temperature as the droplet absorbs energy as the water vapor is released  causes lower pressure.  I do not know where the balance lies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=t4U0njaMfUY&quot; rel=&quot;nofollow&quot;&gt;Here is my attempt (Youtube video) to provide questions and maybe answers&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5446" LastEditorUserId="595" LastEditDate="2016-02-22T09:12:21.520" LastActivityDate="2016-02-22T09:12:21.520" Title="Cloud in a bottle experiment. Why does the &quot;cloud&quot; get thicker with repeated squeezing?" Tags="|clouds|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7514" PostTypeId="2" ParentId="7508" CreationDate="2016-02-15T23:46:16.687" Score="1" Body="&lt;p&gt;There's no significant difference in distribution beneath land and sea. Recovery is all about accessibility. There's plenty of coal under the sea, but we just can't get at it - fortunately! To avoid carbon-driven disaster we have to leave most of the coal and oil where it is, under land or sea.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-02-15T23:46:16.687" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7515" PostTypeId="2" ParentId="7463" CreationDate="2016-02-16T13:34:41.613" Score="2" Body="&lt;p&gt;Amartya,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe this will help clarify:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Convolution in the time domain is equivalent to multiplication in the frequency domain. This is how we build simple convolutional seismograms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;s(t)=w(t)*r(t) =&gt; S(f)=W(f).R(f)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gOhgw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gOhgw.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, what you are trying to do is pretty much the exact opposite. A sinusoid in the time domain is a spike in the frequency domain. And what you are trying to do is &quot;convolve&quot; a gaussian with this spike, all in the frequency domain. But the same rule applies the other way: convolution in the frequency domain is equivalent to multiplication in the time domain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;S(f)=W(f)*R(f) =&gt; s(t)=w(t).r(t)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mXu3O.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mXu3O.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to get a wavelet (in time) whose Fourier transform is a Gaussian centered at a certain frequency, you will need to multiply a sinusoid of that certain frequency by a Gaussian window (in time). This &quot;Gaussian times a sinusoid&quot; is called a Morlet wavelet (or Gabor wavelet in EE).&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;nt=500; % Number of samples in your wavelet&#xA;dt=0.001; % Sample rate in time&#xA;t=dt*((1:nt)-ceil(nt/2))'; % Time vector for wavelet symmetric around zero&#xA;sinusoid=cos(2*pi*fdom.*t+phase); % Sinusoid of desired frequency and phase&#xA;win=exp(-(1*t*fdom).^2); % Gaussian window appropriate for dominant frequency&#xA;wav=win.*sinusoid; % Final Morlet wavelet&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Hope this helps,&lt;br&gt;&#xA;Antonio &lt;/p&gt;&#xA;" OwnerUserId="4636" LastActivityDate="2016-02-16T13:34:41.613" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7516" PostTypeId="2" ParentId="7463" CreationDate="2016-02-16T13:38:06.393" Score="1" Body="&lt;p&gt;(Sorry for the double post, got an image limit)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, as you make that Gaussian window (in time) skinnier and skinnier (by changing that &quot;1&quot; in the window function), you will make the Gaussian in the frequency domain wider and wider, as per the Fourier uncertainty principle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iJDaf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iJDaf.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, I just wanted to point out that a Ricker wavelet does not have a Gaussian amplitude spectrum. It's close but not quite. The Ricker amplitude spectrum is slightly skewed. And they do seem to be using Ricker wavelets in the paper you cited.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OtfCp.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OtfCp.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ok now I'm done. Good luck!&lt;br&gt;&#xA;Antonio &lt;/p&gt;&#xA;" OwnerUserId="4636" LastActivityDate="2016-02-16T13:38:06.393" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7517" PostTypeId="1" AcceptedAnswerId="7518" CreationDate="2016-02-16T15:48:43.727" Score="15" ViewCount="3105" Body="&lt;p&gt;I am working on NCEP GFS data to plot various maps. One such plot I would like to have is visibility. I have seen some of the sites showing visibility charts and the source of the data was shown as NCEP GFS.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I could not find any variable related to visibility in the GFS file. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any specific formula available for calculating visibility? &lt;/p&gt;&#xA;" OwnerUserId="5473" LastEditorUserId="192" LastEditDate="2016-02-16T18:46:16.707" LastActivityDate="2018-03-07T11:41:09.940" Title="What is the formula used for atmospheric visibility?" Tags="|meteorology|atmosphere-modelling|visualization|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7518" PostTypeId="2" ParentId="7517" CreationDate="2016-02-16T18:44:14.513" Score="13" Body="&lt;p&gt;I calculate surface visibility from WRF output using a calculation that I adapted from &lt;a href=&quot;http://www.dtcenter.org/wrf-nmm/users/overview/upp_overview.php&quot;&gt;DTC's Unified Post Processor&lt;/a&gt;, specifically from their Fortran routine found in &lt;code&gt;UPPV2.2/src/unipost/CALVIS.f&lt;/code&gt;. The calculation is based on hydrometeor mixing ratios, and air temperature and pressure, all from the lowest model layer. If your GFS output has hydrometeor mixing ratios, you can use this formula to calculate visibility. The documentation in the original code reads:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;This routine computes horizontal visibility at the&#xA;surface or lowest model layer, from qc, qr, qi, and qs.  &#xA;qv--water vapor mixing ratio (kg/kg)&#xA;qc--cloud water mixing ratio (kg/kg)&#xA;qr--rain water mixing ratio  (kg/kg)&#xA;qi--cloud ice mixing ratio   (kg/kg)&#xA;qs--snow mixing ratio        (kg/kg)&#xA;tt--temperature              (k)&#xA;pp--pressure                 (Pa)&#xA;&#xA;If iice=0:&#xA;   qprc=qr     qrain=qr and qclw=qc if T&amp;gt;0C&#xA;   qcld=qc          =0          =0  if T&amp;lt;0C&#xA;               qsnow=qs and qclice=qc  if T&amp;lt;0C&#xA;                    =0            =0   if T&amp;gt;0C&#xA;If iice=1:&#xA;   qprc=qr+qs   qrain=qr and qclw=qc&#xA;   qcld=qc+qi   qsnow=qs and qclice=qc&#xA;&#xA;Independent of the above definitions, the scheme can use different&#xA;assumptions of the state of hydrometeors:&#xA;     meth='d': qprc is all frozen if T&amp;lt;0, liquid if T&amp;gt;0&#xA;     meth='b': Bocchieri scheme used to determine whether qprc&#xA;        is rain or snow. A temperature assumption is used to&#xA;        determine whether qcld is liquid or frozen.&#xA;     meth='r': Uses the four mixing ratios qrain, qsnow, qclw,&#xA;        and qclice&#xA;&#xA;The routine uses the following&#xA;expressions for extinction coefficient, beta (in km**-1),&#xA;with C being the mass concentration (in g/m**3):&#xA;&#xA;   cloud water:  beta = 144.7 * C ** (0.8800)&#xA;   rain water:   beta =  2.24 * C ** (0.7500)&#xA;   cloud ice:    beta = 327.8 * C ** (1.0000)&#xA;   snow:         beta = 10.36 * C ** (0.7776)&#xA;&#xA;These expressions were obtained from the following sources:&#xA;&#xA;   for cloud water: from Kunkel (1984)&#xA;   for rainwater: from M-P dist'n, with No=8e6 m**-4 and&#xA;      rho_w=1000 kg/m**3&#xA;   for cloud ice: assume randomly oriented plates which follow&#xA;      mass-diameter relationship from Rutledge and Hobbs (1983)&#xA;   for snow: from Stallabrass (1985), assuming beta = -ln(.02)/vis&#xA;&#xA;The extinction coefficient for each water species present is&#xA;calculated, and then all applicable betas are summed to yield&#xA;a single beta. Then the following relationship is used to&#xA;determine visibility (in km), where epsilon is the threshhold&#xA;of contrast, usually taken to be .02:&#xA;&#xA;   vis = -ln(epsilon)/beta      [found in Kunkel (1984)]&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;I have adapted the code from this routine to a Python function below, which you can use for your purposes:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;def calculate_visibility(qv,qc,qr,qi,qs,T,p):&#xA;    &quot;&quot;&quot;&#xA;    Calculates visibility based on the UPP algorithm.&#xA;&#xA;    See documentation in UPPV2.2/src/unipost/CALVIS.f for the description of&#xA;    input arguments and references.&#xA;    &quot;&quot;&quot;&#xA;    Rd = 287.&#xA;    COEFLC = 144.7&#xA;    COEFLP = 2.24&#xA;    COEFFC = 327.8&#xA;    COEFFP = 10.36&#xA;    EXPLC  = 0.88&#xA;    EXPLP  = 0.75&#xA;    EXPFC  = 1.&#xA;    EXPFP  = 0.7776&#xA;&#xA;    Tv   = T * (1+0.61*qv) # Virtual temperature&#xA;&#xA;    rhoa = p/(Rd*Tv) # Air density [kg m^-3]&#xA;    rhow = 1e3       # Water density [kg m^-3]&#xA;    rhoi = 0.917e3   # Ice density [kg m^-3]&#xA;&#xA;    vovmd = (1+qv)/rhoa + (qc+qr)/rhow + (qi+qs)/rhoi&#xA;&#xA;    conc_lc = 1e3*qc/vovmd&#xA;    conc_lp = 1e3*qr/vovmd&#xA;    conc_fc = 1e3*qi/vovmd&#xA;    conc_fp = 1e3*qs/vovmd&#xA;&#xA;    # Make sure all concentrations are positive&#xA;    conc_lc[conc_lc &amp;lt; 0] = 0&#xA;    conc_lp[conc_lp &amp;lt; 0] = 0&#xA;    conc_fc[conc_fc &amp;lt; 0] = 0&#xA;    conc_fp[conc_fp &amp;lt; 0] = 0&#xA;&#xA;    betav = COEFFC*conc_fc**EXPFC\&#xA;          + COEFFP*conc_fp**EXPFP\&#xA;          + COEFLC*conc_lc**EXPLC\&#xA;          + COEFLP*conc_lp**EXPLP+1E-10&#xA;&#xA;    vis = -np.log(0.02)/betav # Visibility [km]&#xA;    vis[vis &amp;gt; 24.135] = 24.135&#xA;&#xA;    return vis&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2016-02-16T18:54:14.503" LastActivityDate="2016-02-16T18:54:14.503" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7519" PostTypeId="1" AcceptedAnswerId="7523" CreationDate="2016-02-17T08:10:47.157" Score="3" ViewCount="280" Body="&lt;p&gt;Radiometric dating is based on heavier elements decaying into lighter elements, for example uranium decaying to lead. But wasn't all uranium in the Solar System created in one or more supernova? And floated around in space for millions or billions of years before accreting to form the Earth and its meteorites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How come the isotopes reflect the time of the accretion of the Earth? How come the accretion affected the ratios of different isotopes, changed the nuclei of atoms? Why doesn't radiometric dating just reflect the age of the supernova in which the isotopes were once created by high energy nuclear fusion processes?&lt;/p&gt;&#xA;" OwnerUserId="3033" LastActivityDate="2016-02-17T16:39:44.547" Title="Why can isotopes reflect the age of the Earth rather than the age of the supernova that created them?" Tags="|radioactivity|dating|isotopic|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7520" PostTypeId="1" AcceptedAnswerId="7521" CreationDate="2016-02-17T09:58:51.537" Score="7" ViewCount="3092" Body="&lt;p&gt;As I understand to compute vector of gravity not saficient to compute normal to elipsoid, but we need to computer normal to &lt;a href=&quot;https://en.wikipedia.org/wiki/Geoid&quot; rel=&quot;noreferrer&quot;&gt;geoid&lt;/a&gt; (by definition geoid is a surface to which the force of gravity is everywhere perpendicular).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I have some questions:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;How to compute normal to geoid?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;What is the maximum discrepancy of angle between elipsoid normal and geoid normal?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jwtBH.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jwtBH.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5hkBm.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5hkBm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Update:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;About practical application of gravity normal:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have some tall object that stand on Earth (like Leaning Tower of Pisa) and I can obtain GPS coordinates of it top and bottom points by using photos taken from air and applying photogrammetry methods. Then from GPS coordinates of top and bottom of object I can get vector in ECEF coordinates and find angle betwen this vector and gravity vector. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also my question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If difference in angle between ellipsoid normal and geoid normal(&quot;deflection of the vertical&quot;) is about 100 seconds of arc (0,0277778 degree) is it safe to use ellipsoid normal for this practical application?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Update 2:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm trying to understand if normal to ellipsoid is sufficient for practical application.&#xA;In real life object is mounted by using &lt;a href=&quot;https://en.wikipedia.org/wiki/Spirit_level&quot; rel=&quot;noreferrer&quot;&gt;spirit level&lt;/a&gt; and on this picture we can see that theoretically I need normal to geoid, but if deflection of vertical small enough I can use normal to ellipsoid as approximation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zhCyA.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zhCyA.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm trying to estimate the error of angle measure, I have some error in calculating of GPS positions of my object top and bottom points say epsilon_1, also I have some error in calculating gravity vector because of I'm using normal to elispoid say epsilon_2 and I'm trying to understand how epsilon_1 and epsilon_2 affects resulting angle between object vector and gravity vector. So I need to derive the formula that will give me measurement error of angle using measurement error of GPS points and gravity vector(epsilon_1 and epsilon_2).&lt;/p&gt;&#xA;" OwnerUserId="5479" LastEditorUserId="5479" LastEditDate="2016-02-17T18:35:45.117" LastActivityDate="2016-02-17T18:35:45.117" Title="Compute direction of gravity vector" Tags="|geophysics|models|gravity|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7521" PostTypeId="2" ParentId="7520" CreationDate="2016-02-17T15:03:34.220" Score="5" Body="&lt;p&gt;First, a distinction between &amp;quot;gravity&amp;quot; and &amp;quot;gravitation&amp;quot; as used in geophysics. &amp;quot;Gravitation&amp;quot; pertains to Newton's law of gravitation. (Nobody uses general relativity to model gravitation for small, lumpy masses such as the Earth, Mars, or the Moon.) &amp;quot;Gravity&amp;quot; pertains to how things appear to fall from the perspective of an observer fixed with respect to the rotating Earth. Thus gravity includes gravitational acceleration (inward, more or less toward the center of the Earth) and centrifugal acceleration (outward, away from the Earth's rotation axis). This question is asking about gravity rather than gravitation.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;As I understand to compute vector of gravity not saficient to compute normal to elipsoid, but we need to computer normal to geoid (by definition geoid is a surface to which the force of gravity is everywhere perpendicular).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It's the other way around. The geoid is a calculated surface. Before the satellite era, one of the key sets of inputs to the calculation of the geoid were observations of deviations of local gravity, particularly the deflection of the vertical. Which way gravity pointed at several locations gave clues as to the local shape of the geoid.&lt;/p&gt;&#xA;&lt;p&gt;Observing the orbits of satellites provides a global measure Earth's gravitational field. Satellites have been specially constructed for this job, most recently, GRACE and GOCE. The Earth's gravitational field is published in terms of spherical harmonics coefficients. The gravitational vector for a point in space on or above the Earth's surface can be calculated directly from these coefficients. Vectorially adding in the centrifugal acceleration due to the Earth's rotation results in the gravity vector. The position also yields the nominal gravity vector assuming an ellipsoidal Earth.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;So I have some questions:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;How to compute normal to geoid?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;As noted above, a geoid is not needed. Modern models of the geoid are calculated from those same spherical harmonic coefficients (plus Earth rotation) that used needed to calculate the gravitational acceleration and gravity.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;What is the maximum discrepancy of angle between elipsoid normal and geoid normal?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The technical term is &amp;quot;deflection of the vertical&amp;quot; (with variations). Per Hirt et al., it's up to 100 seconds of arc, about 10 kilometers south of the peak Annapurna II. This is a calculated value based on various satellite models (which are a bit coarse) coupled with digital terrain maps coupled with some more hairy mathematics to create fine-scale models.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://espace.library.curtin.edu.au/cgi-bin/espace.pdf?file=/2014/03/04/file_1/195882&quot; rel=&quot;noreferrer&quot;&gt;C. Hirt, et al., “New ultrahigh‐resolution picture of Earth's gravity field,” &lt;em&gt;Geophysical Research Letters,&lt;/em&gt; 40.16 (2013): 4279-4283.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-02-17T15:03:34.220" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7522" PostTypeId="2" ParentId="7502" CreationDate="2016-02-17T15:29:48.667" Score="8" Body="&lt;p&gt;To see why we can't perform an experiment in lab conditions to verify the greenhouse effect, we need to start by considering how the [rather badly named] greenhouse effect operates:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth is in (to all intents and purposes) a vacuum, so it can only gain or lose heat via radiation.  The sun emits most of its radiation at visible and UV wavelengths.  The Earth's atmosphere is fairly transparent at these wavelengths and so the Sun's radiation mostly passes through it and hits the surface.  Some of this radiation (determined by the Earth's albedo) is reflected from the surface back out into space, but the rest is absorbed by the surface, which causes the surface to be warm.  The surface loses heat by radiating in infra-red wavelengths.  Greenhouse gases absorb some of the IR radiation, which causes the atmosphere to warm up (the GHG molecules transfer some of this heat to non-greenhouse gasses by collisions, but heat is also transferred upwards by convection).  The warm atmosphere re-radiates some of this energy both upwards into space and downwards back to the surface. The part that is radiated downwards is also known as &quot;back-radiation&quot; (and is directly observable).   Now the important factor is not the amount of outbound IR radiated from the surface that is absorbed, but the altitude at which there are not enough greenhouse gases above to absorb the IR radiated upwards from that layer, so that it can escape out into space.  The lapse rate means that the temperature of the atmosphere decreases with increasing height.  This means that the more CO&lt;sub&gt;2&lt;/sub&gt; we put into the atmosphere, the higher this emitting layer becomes, and the colder it is.  As the amount of IR radiated depends on the temperature of this layer, if this height increases then the amount of IR radiated from the planet falls, leading to an energy imbalance, with the planet absorbing more of the sun's radiation than it emits as IR, and so the planet warms up.  This continues until the radiating layer warms up enough for the outbound IR to be in balance with the incoming radiation from the sun.  So the more CO&lt;sub&gt;2&lt;/sub&gt;, the warmer the mean surface temperature, all things being otherwise equal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in order to have a lab experiment that could replicate the mechanism of the greenhouse effect, we would need a vacuum chamber large enough to contain a vessel containing a column of air high enough to have a measurable lapse rate.  This is clearly impractical.  We can perform experiments in the lab to investigate the absorption of IR by greenhouse gases, and indeed Tyndall did this over a century ago, but we can't experimentally verify the greenhouse effect in laboratory conditions, just as we cannot experimentally demonstrate gravitational lensing in the laboratory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We could of course commission the denizens of &lt;a href=&quot;http://hitchhikers.wikia.com/wiki/Magrathea&quot; rel=&quot;noreferrer&quot;&gt;Magrathea&lt;/a&gt; to construct a replica of the Earth and experiment on that, but we would need a rather large laboratory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This doesn't mean we have no &lt;a href=&quot;https://www.skepticalscience.com/its-not-us-advanced.htm&quot; rel=&quot;noreferrer&quot;&gt;evidence&lt;/a&gt; of the greenhouse effect. Of course we do, just as we do have evidence of gravitational lensing. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Update - &lt;a href=&quot;https://www.aip.org/history/climate/simple.htm&quot; rel=&quot;noreferrer&quot;&gt;brief description&lt;/a&gt; of the mechanism of the greenhouse effect from Spencer Weart's excellent book mentioned by @jamesqf:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What happens to infrared radiation emitted by the Earth's surface? As&#xA;  it moves up layer by layer through the atmosphere, some is stopped in&#xA;  each layer. (To be specific: a molecule of carbon dioxide, water vapor&#xA;  or some other greenhouse gas absorbs a bit of energy from the&#xA;  radiation. The molecule may radiate the energy back out again in a&#xA;  random direction. Or it may transfer the energy into velocity in&#xA;  collisions with other air molecules, so that the layer of air where it&#xA;  sits gets warmer.) The layer of air radiates some of the energy it has&#xA;  absorbed back toward the ground, and some upwards to higher layers. As&#xA;  you go higher, the atmosphere gets thinner and colder. Eventually the&#xA;  energy reaches a layer so thin that radiation can escape into space.  &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;What happens if we add more carbon dioxide? In the layers so high and&#xA;  thin that much of the heat radiation from lower down slips through,&#xA;  adding more greenhouse gas means the layer will absorb more of the&#xA;  rays. So the place from which most of the heat energy finally leaves&#xA;  the Earth will shift to higher layers. Those are colder layers, so&#xA;  they do not radiate heat as well. The planet as a whole is now taking&#xA;  in more energy than it radiates (which is in fact our current&#xA;  situation). As the higher levels radiate some of the excess downwards,&#xA;  all the lower levels down to the surface warm up. The imbalance must&#xA;  continue until the high levels get warmer and radiate out more energy.&#xA;  As in Tyndall's analogy of a dam on a river, the barrier thrown across&#xA;  the outgoing radiation forces the level of temperature everywhere&#xA;  beneath it to rise until there is enough radiation pushing out to&#xA;  balance what the Sun sends in.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Some additional resources for Charlie:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Prof. Ray Pierrehumbert &lt;a href=&quot;https://www.youtube.com/watch?feature=player_embedded&amp;amp;v=slPMD5i5Phg&quot; rel=&quot;noreferrer&quot;&gt;explains the greenhouse effect&lt;/a&gt; whilst sitting comfortably on a courdroy sofa.&lt;/li&gt;&#xA;&lt;li&gt;Prof. Ray Pierrehumbert &lt;a href=&quot;http://www.cruelclimate.net/target/cFovoHfW11QQ0zpjFxUey7J4uQGLD2zI/funnel.php?q=https%3A%2F%2Fgeosci.uchicago.edu%2F~rtp1%2Fpapers%2FPhysTodayRT2011.pdf&quot; rel=&quot;noreferrer&quot;&gt;explains the greenhouse effect&lt;/a&gt; in a journal article.&lt;/li&gt;&#xA;&lt;li&gt;Rasmus Benestad &lt;a href=&quot;http://download-redirector.springer.com/content/static/pdf/875/art%253A10.1007%252Fs00704-016-1732-y.pdf&quot; rel=&quot;noreferrer&quot;&gt;explains the greenhouse effect&lt;/a&gt; in a pedagogical manner in a journal.&lt;/li&gt;&#xA;&lt;li&gt;Some &lt;a href=&quot;http://GreatWhiteCon.info/2016/02/explaining-the-greenhouse-effect/&quot; rel=&quot;noreferrer&quot;&gt;more links&lt;/a&gt; on the topic.&lt;/li&gt;&#xA;&lt;li&gt;For some models with numbers, Charlie could try &lt;a href=&quot;http://climatemodels.uchicago.edu/models.html&quot; rel=&quot;noreferrer&quot;&gt;David Archer's&#xA;website&lt;/a&gt;, I think what Charlie wants would be a combination of the&#xA;MODTRAN model and the RRTM model (I think the fact that Prof. Archer&#xA;has not combined them suggests that it would be a rather non-trivial&#xA;exercise!).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="624" LastEditorUserId="624" LastEditDate="2016-02-18T13:04:02.243" LastActivityDate="2016-02-18T13:04:02.243" CommentCount="19" ContentLicense="CC BY-SA 3.0" />
  <row Id="7523" PostTypeId="2" ParentId="7519" CreationDate="2016-02-17T16:39:44.547" Score="3" Body="&lt;p&gt;Suppose you purify a sample of uranium 238, removing all of the lead. Half of those U-238 atoms will have decayed into lead 4.468 billion years from now. If the lead is removed from that half-uranium/half-lead sample 4.468 billion years from now, half of the U-238 atoms in that purified sample will have decayed into lead in yet another 4.468 billion years. The clock is reset when the decay products are removed. It doesn't matter whether those U-238 atoms were created in one of the very first supernova over ten billion years ago, a supernova shortly before the Earth formed 4.6 billion years ago, or even a supernova that occurred after the Earth formed. Those U-238 atoms do not have a memory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some natural processes do this purification and reset the clock when a rock first forms as a solid object. I'll address two; there are others. Zircons readily bond with uranium and thorium but strongly reject lead. Any lead present in zircons now is a result of the radioactive decay of uranium and/or thorium encapsulated within the zircon when it first formed. Potassium-40 sometimes decays into argon-40. The argon simply bubbles out If that decay happens in molten rock. They argon remains trapped if the decay happens inside a solidified crystal. Any argon present in a rock crystal now is a result of the radioactive decay. In both cases, (zircons containing uranium-238 and rock crystals containing potassium-40), the clock was reset when the rock first formed.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2016-02-17T16:39:44.547" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7524" PostTypeId="1" CreationDate="2016-02-17T17:38:25.427" Score="4" ViewCount="146" Body="&lt;p&gt;Can some one explain me the basics of downscaling (interpolate to a smaller cell) a global meteorology data to a local scale (2 km × 2 km). IF would be very thankful if you provide a link at least. is it possible? Main variables are U&lt;sub&gt;x&lt;/sub&gt; U&lt;sub&gt;y&lt;/sub&gt;, temperature, pressure.&lt;/p&gt;&#xA;" OwnerUserId="5482" LastEditorUserId="725" LastEditDate="2016-02-20T10:58:28.647" LastActivityDate="2016-02-20T10:58:28.647" Title="Downscaling global meteorology data" Tags="|meteorology|wrf|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7525" PostTypeId="1" CreationDate="2016-02-17T17:46:51.260" Score="1" ViewCount="398" Body="&lt;p&gt;We are a group of computer science students currently working on a university project to create a (almost) self-sufficient greenhouse.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The hardware and software aspects being almost finished, we would now want to begin testing. To do so, given that we are very far from being specialists in the matter, we are looking for a database or a reference book about optimal conditions for fruit/vegetable growth in a small format greenhouse.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The project being mainly to show the software and hardware aspects of it, the aim isn't for long-term growth or a full-fledged production. We are looking to grow, for example, tomatoes and/or strawberries long enough to show that the process works in theory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sorry for the weird question. Thanks in advance!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS: I did post this question on the Biology SE, which sent me to the Gardening SE, which found the question to be off-topic. Hoping to be a bit more lucky here.&lt;/p&gt;&#xA;" OwnerUserId="5484" LastActivityDate="2018-05-11T14:17:03.700" Title="Database/Reference on optimal conditions for plant growth in greenhouses" Tags="|open-data|database|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7526" PostTypeId="1" CreationDate="2016-02-18T01:49:56.013" Score="7" ViewCount="1522" Body="&lt;p&gt;I am doing some literature review on desertification. However, I could not find any information related to my question. Based on my knowledge, barren land faced greater heating and wind than vegetated area but the presence of vegetation can lead to a huge increase in evaporation surface area. They seem to me opposing factors. Based on my intuitive guess, I would say barren land would suffer bigger water loss but has there been any reliable research done on this? Is there a method to calculate and compare the gross water loss of the two scenarios?&lt;/p&gt;&#xA;" OwnerUserId="3241" LastEditorUserId="3241" LastEditDate="2016-02-18T04:24:05.843" LastActivityDate="2022-05-25T16:39:08.620" Title="In general, does the presence of vegetation increase/decrease gross water loss (evapotranspiration) compared to barren land (evaporation only)?" Tags="|desert|evaporation|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7527" PostTypeId="2" ParentId="2553" CreationDate="2016-02-18T02:40:09.477" Score="1" Body="&lt;p&gt;Outgassing is a process by which $O_{2}$, $CO_{2}$ and other chemicals are released as a result of heat or increase in temperature. It is different from advection and diffusion which are mixing processes as a result of temperature and concentration gradient. Outgassing is an abrupt release of gases from where they are stored trapped dissolved, in this case  $O_{2}$ and  $CO_{2}$ in the ocean. Like the ocean some materials are prone to outgassing when heated. For example chemicals released from plastics (e.g. the odor of a new car). &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What is the relative importance on mixing of the vertical flow of&#xA;  gases in the ocean water column?&#xA;  How does the mixing compare with physical mixing (e.g., wind, internal wave breaking) and molecular diffusion?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The rate of outgassing in ocean is comparable to molecular diffusion of the gases. However, the mechanisms of outgassing and diffusion are different,i.e, outgassing occurs due to some sort of pumping mechanism but diffusion occurs due concentration gradient. Both mechanisms are important to stratify saturation,i.e. homogeneous distribution of chemicals. &#xA;Having said this, comparison of diffusion and outgassing needs further investigation. However, I don't think outgassing like diffusion can be triggered by saturation. Some kind of pumping mechanism attributed to difference in surface layers (e.g. the creation of temporary vacuum layer) may trigger outgassing. &#xA;In connection with climate change, ocean oxygen and carbon dioxide outgassing into the atmosphere are decreasing ocean oxygen and increasing atmospheric carbon dioxde. Both events have negative consequences. Decrease in ocean oxygen has impacted ocean plants and animals. So, outgassing if occurs within the ocean can be taken as a mixing process but if it throws out the molecules out of the ocean has negative consequences both for the ocean and atmosphere. &lt;/p&gt;&#xA;" OwnerUserId="4877" LastEditorUserId="4877" LastEditDate="2016-02-19T00:26:01.533" LastActivityDate="2016-02-19T00:26:01.533" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7529" PostTypeId="1" CreationDate="2016-02-18T05:17:37.447" Score="6" ViewCount="155" Body="&lt;p&gt;How to obtain the divergence of velocity field $\left(\nabla.\mathbf{u}\right)$ with ${Q}$ (something proportional to the diabatic heating rate)  as the source term from the thermodynamic equation?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Such an equation (non-dimensionalized and in isobaric co-ordinates) is presented in A. E. Gill's 1980 paper on tropical circulation in the atmosphere (&lt;a href=&quot;http://doi.org/10.1002/qj.49710644905&quot; rel=&quot;nofollow&quot;&gt;http://doi.org/10.1002/qj.49710644905&lt;/a&gt;): $\frac{\partial p}{\partial t}+\frac{\partial u}{\partial x}+\frac{\partial v}{\partial y}=-{Q}$, where $u$ and $v$ are horizontal ( in $x,\ y$ directions) perturbation velocities and $p$ is proportional to the perturbation pressure.&lt;/p&gt;&#xA;" OwnerUserId="5378" LastEditorUserId="5378" LastEditDate="2016-02-19T11:46:47.037" LastActivityDate="2016-02-19T11:46:47.037" Title="Forced shallow-water equation with diabatic heating as the source term" Tags="|atmosphere-modelling|tropical-cyclone|atmospheric-circulation|synoptic|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="7531" PostTypeId="2" ParentId="7508" CreationDate="2016-02-18T19:28:01.830" Score="0" Body="&lt;p&gt;A more fair comparison would be between the presence of coal and that of hydrocarbon-generating source rocks. Although hydrocarbons can be generated by cooking any rock with a high enough concentration of hydrocarbon-bearing organic matter (i.e. kerogen), the maps you are showing are for the accumulations of trapped hydrocarbons after they have migrated away from their source rock. The vast majority of hydrocarbons ever generated by cooking a source rock in depth have migrated to the surface and been degraded by bacteria.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The places where you will find hydrocarbons not only require a buried source rock, but also a migration pathway, a reservoir, a trap, a seal, and all of it happening at the right time; you need a whole petroleum system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am sure that there are other constraints about where to find coal seams as well. For example, There are probably many coal seams that have been buried in a way that they are not accessible and are therefore not counted on those maps. But I'm not that familiar with the geology of coals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-Antonio&lt;/p&gt;&#xA;" OwnerUserId="4636" LastActivityDate="2016-02-18T19:28:01.830" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7532" PostTypeId="1" CreationDate="2016-02-11T17:48:06.517" Score="6" ViewCount="46" Body="&lt;p&gt;Background:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The soil in our locality is/was Black Cotton Soil - mostly from weathered humus over the years. Our locality was also mostly large (by Indian standards) plots mostly with load-bearing walls - so there plenty of houses had enormous trees/gardens/what-not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Over the last decade or two - the old load-bearing houses with clay-tile roofs have been replaced by multi-storey concrete column/beam apartments. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The result is drier soil ( we hit 46C regularly in summer for upto 3 weeks this part of the world ) in those parts of the locality that have not been concreted/asphalted over by construction/roads during the dry part of the year. The converse is true during the wet part of the year - extreme waterlogging is observed. Larger trees survive - smaller plants do not... or barely so. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suspect this may be due to a double-whammy - greater sewage, and greater run-off after rain due to the soil excavated to accommodate concrete, smaller number of trees/roots to absorb moisture &amp;amp; retard soil runoff.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the expected changes in the water-table of a locality &lt;em&gt;post&lt;/em&gt; &quot;evolution&quot; to a concrete column/beam structure?&lt;/p&gt;&#xA;" OwnerUserId="743" OwnerDisplayName="Everyone" LastActivityDate="2016-02-19T06:17:52.570" Title="Is there a study relating water table to construction/RCC activity?" Tags="|water|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7533" PostTypeId="1" AcceptedAnswerId="7536" CreationDate="2016-02-19T10:18:49.133" Score="11" ViewCount="5866" Body="&lt;p&gt;This question popped into my head because I am designing a fictional world map, and I was wondering what factors influence the amount of ice at poles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to know why there is much more ice covering South Pole than North Pole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An answer I found &lt;a href=&quot;http://www.scientificamerican.com/article/why-is-the-south-pole-col/&quot;&gt;here&lt;/a&gt; states:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;What makes the South Pole so much colder than the North Pole is that it sits on top of a very thick ice sheet, which itself sits on a continent.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does that mean that if there was a continent at North Pole, there would also be much more ice there? Is impact of Gulf stream also a factor in this or no?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think I am on the right track but someone more knowledgeable than me could really clear this up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you in advance!&lt;/p&gt;&#xA;" OwnerUserId="5491" LastActivityDate="2016-02-20T02:37:48.730" Title="Why is the South Pole colder than the North Pole?" Tags="|meteorology|geophysics|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="7534" PostTypeId="2" ParentId="4948" CreationDate="2016-02-19T12:26:46.870" Score="1" Body="&lt;p&gt;Rock composition of typical oceanic crust consists of mineral assemblages that are significantly denser than typical continental crust.  Thickness of crust has really nothing to do with its density. Plate tectonics, sedimentation, and volcanic activity will play a significant the crust thickness.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ability of upper crust to float on top of the lower crust/mantle is due to isostacy. Similar to about a helium balloon in the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2016-02-19T12:26:46.870" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7536" PostTypeId="2" ParentId="7533" CreationDate="2016-02-19T16:29:57.443" Score="13" Body="&lt;p&gt;The most obvious reason why the South pole is colder than the North pole is altitude. The Arctic is mostly covered by ocean and low lying land whereas the Antarctic continent is really quite high, with an average height of about 2,400m. The environmental lapse rate in the troposphere is about 6.5°C/km and so this corresponds to about a 15°C temperature difference between the Arctic and Antarctic based on altitude alone. Obviously the actual temperature difference is greater than this so there must be something else at work. Most of Antarctica is only this high because it has a couple of kilometres of ice sitting on top of it and so this doesn't explain why there is a huge, permanent (at least for the last ~35 million years) ice sheet sitting there in the first place.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two main reasons why a large ice sheet can persist at the South pole. First is that the southern polar region is currently covered by a large continental land mass (Antarctica). Land has a much lower heat capacity than water and so in the Arctic, the ocean acts as a large reservoir of heat, mainly transported there from lower latitudes and this limits the sea ice thickness. Conversely, in Antarctica snow can accumulate on the land and, if it does not melt in the summer, it will be buried next winter, leading to ice accumulation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second reason is the existence of the cold Antarctic Circumpolar Current which flows from west to east and is the largest ocean current in the world, with a mean transport of 100-150Sv. This cold current, transporting huge volumes of water, serves to thermally insulate Antarctica from the warmer subtropical waters to the north, cooling the continent. The openings of the Drake Passage and the Tasman Gateway, the exact timings of which are debated but are generally thought to have both happened by about 30 million years ago, allowed the formation of the ACC and are roughly coincident with the onset of permanent glaciation in Antarctica.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An additional factor in the present day, as mentioned @winwaed, is that southern hemisphere winter solstice currently coincides with aphelion (roughly), which produces colder winters in the southern hemisphere, allowing extreme temperatures of -94.7°C to be reached. The flip side of this is that summer solstice coincides with perihelion, which produces higher summer temperatures.&lt;/p&gt;&#xA;" OwnerUserId="2570" LastEditorUserId="2470" LastEditDate="2016-02-20T02:37:48.730" LastActivityDate="2016-02-20T02:37:48.730" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7537" PostTypeId="1" AcceptedAnswerId="9131" CreationDate="2016-02-20T03:48:42.840" Score="4" ViewCount="3687" Body="&lt;p&gt;I have seen many times that their are two kinds of Satellite Images shown on the websites like &lt;a href=&quot;http://skymetweather.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;Skymet for India&lt;/a&gt; i.e.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Meteosat satellite images&lt;/strong&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Insat satellite images&lt;/strong&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I want to understand the basic difference between them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am here Adding 2 satellite Images(Meteosat and Insat Images Respectively) for the date of 20/02/2016 and time 8:00AM (IST) to make you understand better visually.&lt;a href=&quot;https://i.stack.imgur.com/vt3w4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vt3w4.png&quot; alt=&quot;Meteosat image&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/78EKT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/78EKT.png&quot; alt=&quot;Insat Image&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for your help in advance.&lt;/p&gt;&#xA;" OwnerUserId="5093" LastEditorUserId="192" LastEditDate="2016-06-26T16:01:34.133" LastActivityDate="2021-03-08T09:33:50.963" Title="Difference between Meteosat and Insat satellite Images" Tags="|measurements|remote-sensing|satellites|" AnswerCount="4" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="7539" PostTypeId="2" ParentId="7537" CreationDate="2016-02-20T07:41:21.590" Score="4" Body="&lt;p&gt;&lt;strong&gt;Meteosat:-&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Meteosat series of satellites are geostationary meteorological satellites operated by EUMETSAT under the Meteosat Transition Programme (MTP) and the Meteosat Second Generation (MSG) program.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;INSAT:-&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;INSAT-3D is the first Indian geostationary satellite, equipped with sounder instrument that provides frequent good quality atmospheric profiles (temperature, humidity) over Indian landmass and adjoining areas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More information is here: &lt;a href=&quot;http://www.eumetsat.int/website/home/Satellites/CurrentSatellites/Meteosat/index.html&quot; rel=&quot;nofollow&quot;&gt;Two generations of active Meteosat satellites, Meteosat First Generation (MFG) and Meteosat Second Generation (MSG), providing images of the full Earth disc, and data for weather forecasts.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and here: &lt;a href=&quot;http://www.isro.gov.in/insat-3d/insat-3d-advanced-weather-satellite-completes-two-years-orbit&quot; rel=&quot;nofollow&quot;&gt;INSAT-3D, Advanced Weather Satellite, Completes Two Years in the Orbit.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5473" LastEditorUserId="6093" LastEditDate="2016-09-11T08:35:26.980" LastActivityDate="2016-09-11T08:35:26.980" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7541" PostTypeId="1" CreationDate="2016-02-20T09:23:27.797" Score="4" ViewCount="4301" Body="&lt;p&gt;I am working WRF outputl file and require to extract wind and temp values at 850 hPa, 700 hPa and 500 hPa pressure levels. As the WRF vertical coordinates are based on eta level, I am having trouble in getting parameters at different pressure level. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am working python. It would be nice if anyone point in right direction. I want the concept as it can be used with any post processing tools. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit:-&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think the question is not clear. The wrfout file contain 27 vertical level and the value ranges between 1.0 to 0. In this case, how do I know that 0.98 corresponds to 950 hPa or 850 hPa etc..&lt;/p&gt;&#xA;" OwnerUserId="5473" LastEditorUserId="5473" LastEditDate="2017-01-17T16:42:06.697" LastActivityDate="2017-01-17T16:42:06.697" Title="How to convert eta level to pressure level in WRF model" Tags="|atmosphere|atmosphere-modelling|upper-atmosphere|wrf|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7543" PostTypeId="1" AcceptedAnswerId="7546" CreationDate="2016-02-20T18:31:38.633" Score="0" ViewCount="54" Body="&lt;p&gt;What is the science behind the vigorous glow of stars ? Since 2 days I was observing one of the stars in blue and red colour I just want to know what is the speciality of that star?&lt;/p&gt;&#xA;" OwnerUserId="5498" LastActivityDate="2016-03-22T01:30:24.580" Title="Stars twinkling" Tags="|planetary-science|" AnswerCount="1" CommentCount="2" ClosedDate="2016-03-23T02:37:33.890" ContentLicense="CC BY-SA 3.0" />
  <row Id="7545" PostTypeId="2" ParentId="7266" CreationDate="2016-02-20T23:26:54.497" Score="8" Body="&lt;p&gt;Taken straight-out from Prof. L. Braile's &lt;a href=&quot;https://web.ics.purdue.edu/~braile/edumod/eqhazard/eqhazard1.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;collection of earthquake hazard information&lt;/a&gt;, that explains it quite nicely:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The magnitude scale is really comparing amplitudes of waves on a seismogram, not the STRENGTH (energy) of the earthquakes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;While one unit of magnitude is 10 times the amplitude on a seismogram, one unit of magnitude represents $10^{1.5}$ times (approximately 32 times) the energy, based on the long-standing empirical formula&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\log{E} \propto 1.5M$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;thus&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$E \propto 10^{1.5M}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $E$ is energy and $M$ is magnitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The example set in the webpage is to compare how much bigger would a 9.7 magnitude earthquake be in comparison to a 6.8 magnitude earthquake:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The magnitude scale is logarithmic, so a magnitude 9.7 earthquake is $\frac{10^{9.7}}{10^{6.8}} = 794.328$ times bigger on the seismogram than a magnitude 6.8 earthquake.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Measuring the change in energy, however, shows that the 9.7 earthquake is $\frac{{10^{1.5}}^{9.7}}{{10^{1.5}}^{6.8}} = 10^{1.5 \times (9.7-6.8)} = 22~387$ times the energy of a 6.8 earthquake.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Comparison of earthquake &quot;size&quot; on seismograms: this &lt;a href=&quot;http://crack.seismo.unr.edu/ep/nvguide/images/sbg4g.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;image&lt;/a&gt; from Nevada Seismological Lab's &lt;a href=&quot;http://crack.seismo.unr.edu/ep/nvguide/sbg4.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Living with Earthquakes in Nevada&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://youtu.be/YXMKSOsv3QA&quot; rel=&quot;nofollow noreferrer&quot;&gt;A graphical comparison of earthquake energy release&lt;/a&gt;, a video by the US NWS Pacific Tsunami Warning Center (PTWC).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The USGS has &lt;a href=&quot;http://earthquake.usgs.gov/learn/topics/calculator.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;a calculator&lt;/a&gt; for magnitude difference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And there's a calculator for &lt;a href=&quot;http://www.alabamaquake.com/energy.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;seismic energy and several equivalences&lt;/a&gt;. Unfortunately, most of the equivalences are related to the USA.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;https://earthscience.stackexchange.com/a/7837/5293&quot;&gt;Brian Hill's answer&lt;/a&gt; that explains that with the original Richter scale, one unit of magnitude is apprimately $31^{1}$ times the energy, and two units of magnitude are $31^{2}$ times the energy, and so on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;In short&lt;/strong&gt;: you are half-right (one unit of magnitude it is 10 times bigger on the seismogram, not in energy), and the book is right (two units of magnitude are 1000 times stronger).&lt;/p&gt;&#xA;" OwnerUserId="5293" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-05-18T22:19:05.100" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7546" PostTypeId="2" ParentId="7543" CreationDate="2016-02-21T01:08:21.407" Score="1" Body="&lt;ul&gt;&#xA;&lt;li&gt;Stars do have different colors depending of their temperature, &lt;/li&gt;&#xA;&lt;li&gt;different intensities depending of their size, temperature and distance,&lt;/li&gt;&#xA;&lt;li&gt;twinkle is due to turbulence in the atmosphere (you don't have it in space).&lt;/li&gt;&#xA;&lt;li&gt;the glow you might see is a effect in your telescope, camera or eye. It has several components due to the opening size, imperfect lense, and captors.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="4726" LastActivityDate="2016-02-21T01:08:21.407" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7547" PostTypeId="2" ParentId="3127" CreationDate="2016-02-21T01:16:01.390" Score="2" Body="&lt;p&gt;The atmosphere is continuously mixed by turbulence, so no sorting of its  ordinary components can occur easily and rapidly. Twice a day change, anyway, is far too fast for anything but some tidal effect on pressure and thus on temperature. Ok, these might indirectly slightly modify some thresholds and balance e.g. between states change (water) and some atmospheric chemistry, by a fraction of what day/night change does. I wouldn't call that &quot;change of composition&quot;, though.&lt;/p&gt;&#xA;" OwnerUserId="4726" LastEditorUserId="725" LastEditDate="2016-02-28T04:48:30.767" LastActivityDate="2016-02-28T04:48:30.767" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7549" PostTypeId="1" CreationDate="2016-02-21T05:47:18.330" Score="1" ViewCount="74" Body="&lt;p&gt;My grandfather found this thing.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/u59pr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/u59pr.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5503" LastEditorUserId="5503" LastEditDate="2016-02-21T05:56:08.797" LastActivityDate="2016-02-21T08:08:20.403" Title="What type of mineral is this?" Tags="|rocks|mineralogy|minerals|" AnswerCount="1" CommentCount="3" ClosedDate="2016-02-23T21:29:30.873" ContentLicense="CC BY-SA 3.0" />
  <row Id="7550" PostTypeId="1" CreationDate="2016-02-21T06:48:42.250" Score="1" ViewCount="260" Body="&lt;p&gt;(Edited). Biotic pump theory (2006): &lt;em&gt;Forests cause enhanced transpiration and precipitation and create areas of low pressure that suck in more moisture in a positive feedback loop&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A few years ago an international team found the mechanism for enhanced precipitation.  They found that fungi release potassium salts late at night, as they release spores, and that plants release turpenes and isoprenes in the morning and these sublime onto the salt in the sunlight  to form extremely good condensation nuclei. Source: &lt;a href=&quot;http://science.sciencemag.org/content/337/6098/1075.full&quot; rel=&quot;nofollow&quot;&gt;Biogenic Potassium Salt Particles as Seeds for Secondary Organic Aerosol in the Amazon&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I made &lt;a href=&quot;https://www.youtube.com/watch?v=NwGzAwOyla4&quot; rel=&quot;nofollow&quot;&gt;a video about this&lt;/a&gt;.&lt;br /&gt;The second part, from about 7 minutes into the video, clearly shows cumulonimbus clouds forming at approximately 3 to 4 pm over forested areas of Cuba, Florida and Mexico. This is consistent with the biotic pump theory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The biotic pump theory is that enhanced transpiration and precipitation  over forested areas causes low pressure areas and attracts wind (laden with moisture) from elsewhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To create a low pressure area, the clouds have to remove some gas from the area,  and they do so by transporting air up into the next layer of the atmosphere. The &quot;tail&quot; of the hurricane (the stream of wind delivered to the upper atmosphere by the hurricane actually demonstrates that this is happening.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When its tail  passes over those areas,  its moisture condenses on the condensation nuclei that have passed up through the cloud with the dry air into that higher layer of the atmosphere.   The main problem that the biotic pump theory has is that it was proposed by nuclear physicists. They suggest that several of the &quot;assumptions&quot; on which meteorology are based violate the laws of thermodynamics. Coming from mere nuclear physicists,  this should give people pause for thought. But the biggest problem has been a communication problem.  The meteorological community have found the mathematics they use almost incomprehensible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How do you read the evidence? &lt;/p&gt;&#xA;" OwnerUserId="5446" LastEditorUserId="595" LastEditDate="2016-02-22T09:12:13.817" LastActivityDate="2016-02-22T21:26:09.100" Title="Does the Nasa video show proof of the biotic pump theory?" Tags="|clouds|" AnswerCount="0" CommentCount="20" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7551" PostTypeId="2" ParentId="7549" CreationDate="2016-02-21T08:08:20.403" Score="1" Body="&lt;p&gt;The green material indicates the potential presence of copper &amp;amp; the shiny bits on the lower left &amp;amp; mid right of the specimen look metallic, but that could be just glint in the picture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, there are two groves on the lower right which may indicate a soft metal like copper.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If it is metallic it could be native copper or it could be lump of copper from a foundry.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-02-21T08:08:20.403" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7552" PostTypeId="1" CreationDate="2016-02-21T11:54:19.717" Score="1" ViewCount="110" Body="&lt;p&gt;Sulfate is one important inorganic aerosol in the atmosphere. It's subject to removal by two main mechanisms.   &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Wet deposition which include rain/wash-out and cloud deposition.    &lt;/li&gt;&#xA;&lt;li&gt;Dry deposition which include impaction,diffusion,gravitational settling and etc.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;This &lt;a href=&quot;http://www.aos.wisc.edu/uwaosjournal/Volume22/Karambelas_MSThesis.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;master thesis&lt;/a&gt; says:    &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Sulfate aerosol, in particular, is heavily impacted by dry deposition, which accounts for 40% of the total sulfur deposition on average (Baumgardner et al., 2002; Butler &amp;amp; Likens, 1995) and up to 55% of total sulfur deposition in forested regions (Linderg &amp;amp; Lovett, 1992).&lt;br&gt;&#xA;  Aerosol dry deposition depends on wind speed, solar radiation, and the type and condition of ground cover (Sheih et al., 1979).   &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But I'm confused about the status of forested region, which have the high relative humidity, frequent rain, and more surface the aerosol can condense on (cloud deposition process: In high elevation ecosystem, the cloud droplets can be interception by vegetation). In my opinion, it should enhance the wet deposition of sulfate&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Does someone know why the dry deposition perform better in forested regions?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="5594" LastEditDate="2017-12-13T10:17:50.473" LastActivityDate="2017-12-13T10:17:50.473" Title="Dry deposition of the total sulfate deposition in forested region" Tags="|atmosphere|geochemistry|atmospheric-chemistry|air-pollution|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7553" PostTypeId="1" CreationDate="2016-02-21T22:16:17.883" Score="21" ViewCount="23590" Body="&lt;p&gt;This is a childhood dream. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would happen if pipes were installed (similar in principle to &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Man-Made_River&quot;&gt;the Great Man-Made River&lt;/a&gt;, but for seawater) to continuously pump seawater into the Sahara desert. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's say that a precise desert location, with no known aquifer nor water table, was chosen to be an inner sea. And let's say that wildlife was negligible at that location. And that solar panels were installed to provide energy for the pumping of the water. And that the water was pumped at the surface of the Mediterranean sea and that precautions were taken not to greatly damage sea life.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How hard will it be to fill, say, a Nevada sized inner salty lake? And would that humidify the air enough that dew - falling to the ground each night - would somehow start a greening cycle? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What if a little mud was added to the water to precipitate into a bed that would retain the lake? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any modification to this childish plan that would make it, at least, realizable?&lt;/p&gt;&#xA;" OwnerUserId="5506" LastEditorUserId="2536" LastEditDate="2017-05-28T10:08:21.097" LastActivityDate="2017-05-28T10:08:21.097" Title="What would be the effect of bringing seawater pipes to the Sahara desert?" Tags="|meteorology|climate-change|water|desert|geoengineering|" AnswerCount="4" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="7554" PostTypeId="1" CreationDate="2016-02-22T08:24:28.747" Score="1" ViewCount="391" Body="&lt;p&gt;The lightning is often a discharge in advance. The (negative) charge slide occasionally a little further on in the conductive channel, wherein said channel is highlighted each time something. The lowering speed of the discharge is &quot;only&quot; about 1,500 kilometers per second.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main discharge provides the lightning that we usually perceive (which appears from the clouds to the earth, but not in reality). After the discharge of this strong flow fills the entire channel. This is called the main discharge or sometimes the 'backlash' (return stroke).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This phenomenon, with intense light accompanied, moves at about 100,000 to 150,000 km / s from the earth to the cloud. In this situation, the electrons move down and our speech becomes the current direction counted up. After all, the electric current runs from plus to minus, as opposed to the electrons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the question now is how electrons that emerge give a flash of light which goes up?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See also : &lt;a href=&quot;https://earthscience.stackexchange.com/questions/580/why-does-lightning-strike-from-the-ground-up&quot;&gt;Why does lightning strike from the ground-up?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2018-02-09T08:30:26.963" Title="Why is lightning going from the Earth to the clouds while the electrons are going from the clouds to the Earth?" Tags="|meteorology|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7556" PostTypeId="1" CreationDate="2016-02-22T19:13:20.390" Score="9" ViewCount="228" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/r7BQ6.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/r7BQ6.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to know the name(s) of this ice formation.&#xA;How common or rare is it?&#xA;What other regions of the world does this occur in?&#xA;What specific requirements are needed to produce it and could it be reliably produced in a lab or a fountain or pond?&#xA;What other structures are similar to this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We also have a video which shows the center of the growing columns bubbling with orange froth, which appears to supply material to the sides of the columns as it grows.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These columns appear to be about two feet or 60 cm high and about eight inches or 20 cm in diameter for the largest ones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They do not look like they take the shapes of crystals, rather, like the precipitation chimneys of undersea hydrothermal vents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I heard that this kind of structure has been seen in Nova Scotia. I also heard they form in more than one creek in or near Hamilton, Ontario, Canada (where the pictures and videos were taken). I also heard this has happened in other years, not just this year.&lt;/p&gt;&#xA;" OwnerUserId="5511" LastEditorUserId="2470" LastEditDate="2016-02-23T13:39:34.217" LastActivityDate="2016-05-29T16:57:27.150" Title="In -20 °C weather, creeks below waterfalls here form ice columns. What are these called? Ice-canoes?" Tags="|hydrology|water|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7558" PostTypeId="1" CreationDate="2016-02-22T22:51:51.057" Score="2" ViewCount="115" Body="&lt;p&gt;On p. 6 of this article:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.igsoc.org:8080/journal/57/204/t10J220.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bliss, A.K., Cuffey, K.M., Kavanaugh, J.L., 2011. Sublimation and surface energy budget of Taylor Glacier, Antarctica. Journal of Glaciology 57, 684–696.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is an expression for sublimation rate as a function of latent heat flux $L$ and (specific) latent heat of sublimation (of water ice) $\lambda$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/9TSBm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But then $L$ itself is given as a function of the latent heat of sublimation ($\lambda$):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/3ED58.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So... doesn't $\lambda$ cancel out!? This would imply that the latent heat of sublimation doesn't matter at all here, which I guess is possible since it's a kinetically controlled process.&lt;/p&gt;&#xA;" OwnerUserId="63" LastEditorUserId="63" LastEditDate="2016-02-22T22:58:52.767" LastActivityDate="2016-02-22T22:58:52.767" Title="Doesn't the sublimation rate on glaciers depend on the (specific) latent heat of sublimation of water ice?" Tags="|glaciology|thermodynamics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7559" PostTypeId="2" ParentId="4999" CreationDate="2016-02-23T06:23:59.670" Score="-1" Body="&lt;p&gt;Alternative earth models and their origins are awesome to review.&#xA;The ignorant adherence to the flat earth model in the 21st century is sad. Looking at the material cited for the 'Bedford Level experiment' it's clear to me that those still using Rowbotham's formula have another fundamental problem aside from refraction distortion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You cannot site 8 inches per mile squared if the observer and target(ways off in water) have a positive y-axis value relative to sea level. Somebody using this formula without getting their eye wet is wasting their time! Learn to solve for the height of a curve, anything inside the peak height of an arc equal to the height of the observer will be visible provided conditions are clear and one looks down about .025 degrees from their 0• level visual field.&lt;/p&gt;&#xA;" OwnerUserId="5515" LastActivityDate="2016-02-23T06:23:59.670" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7560" PostTypeId="2" ParentId="7553" CreationDate="2016-02-23T14:11:53.357" Score="15" Body="&lt;p&gt;This is an interesting question &amp;amp; I've been waiting to see what answers, if any, would be written.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One affect of creating such a lake would be a localized increase in humidity in the vicinity of the new lake, but nothing that would significantly increase rainfall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By bringing in salty sea water there could be a risk of contaminating existing underground fresh water stores with salt, making such sources of water unusable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, by being salty, the water could not be used irrigate crops. It may be possible to establish a fishery in the lake, bringing in salt water species of fish, but that would need to be carefully managed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If for whatever reason, the supply of water was not maintained in the lake, eventually the lake would dry up leaving salt behind. This would then be blow around by the wind, contaminating the nearby land with salt and killing plants on that land and making the land unsuitable for any crops that may grow there now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, if dew were to form, there is no control over how much dew would be created. Many factors come into play when dew forms: atmospheric pressure, wet and dry bulb temperatures, the amount of moisture in the air (humidity) and enthalpy of water vapour and liquid water.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Edit&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Having thought about this some more, something similar to what you are proposing has already been done in Egypt, when the &lt;a href=&quot;https://en.wikipedia.org/wiki/Suez_Canal&quot;&gt;Suez Canal&lt;/a&gt; was completed and opened in 1869.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Within the canal system is &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Bitter_Lake&quot;&gt;Great Bitter Lake&lt;/a&gt;, which is a sea water lake. The presence of such a body of water for nearly 150 years has not increased the amount of moisture in the vicinity of the lake that would allow lush vegetation to grow.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2016-02-24T09:38:58.923" LastActivityDate="2016-02-24T09:38:58.923" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7562" PostTypeId="1" AcceptedAnswerId="7576" CreationDate="2016-02-23T20:39:32.140" Score="5" ViewCount="3348" Body="&lt;h1&gt;1. Question:&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;In the article, &lt;a href=&quot;http://www.skepticalscience.com/climate-change-global-warming.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Warming vs. Climate Change&lt;/a&gt; is an example of the confusion regarding these terms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;What are the &quot;official&quot; definitions of &quot;Climate Change&quot; and &quot;Global Warming&quot;?&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How does the &lt;a href=&quot;http://www.ipcc.ch/&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC&lt;/a&gt; - distinguish between &quot;&lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2790086/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Warming&lt;/a&gt;&quot; and &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_change&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate Change&lt;/a&gt;&quot;; or, are the terms interchangeable?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Clarification:&lt;/strong&gt; &#xA;To avoid &quot;opinion&quot; / &quot;debate&quot;, I am just hoping for authoritative definitions. Specifically, I am hoping to clarify the different uses seen in &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7591/research-studies-underlying-objections-to-ipcc-climate-change-theory&quot;&gt;objections raised within the science community, (Question Link)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;h1&gt;2. Example Ambiguities:&lt;/h1&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Global Warming&lt;/strong&gt; - a relentless rise in temperature? Due to both natural and human contributors?  Or exclusively to pollution?  Associated with the &lt;a href=&quot;http://climate.nasa.gov/climate_resources/24/&quot; rel=&quot;nofollow noreferrer&quot;&gt;relentless rise in Carbon Dioxide levels&lt;/a&gt;, or perhaps &lt;a href=&quot;http://www.pnas.org/content/97/18/9875.full.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chlorofluorocarbons&lt;/a&gt;, etc.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Climate Change&lt;/strong&gt; - A competing theory? A newer refinement of Global Warming Theory? Extreme, and unpredictable variability in climate--rather than a consistent, relentless increase in heat.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Corollary Theories&lt;/strong&gt; -  Is Climate Change is a larger study, and Global warming falls within, or one causes the other, etc?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="5521" LastEditorUserId="28050" LastEditDate="2018-02-01T00:46:34.440" LastActivityDate="2018-02-01T00:46:34.440" Title="What is the difference between climate change and global warming?" Tags="|climate-change|terminology|environmental-protection|research|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7563" PostTypeId="2" ParentId="7562" CreationDate="2016-02-23T23:21:17.300" Score="16" Body="&lt;blockquote&gt;&#xA;  &lt;ol&gt;&#xA;  &lt;li&gt;Is &quot;Climate Change&quot; a derived theory within &quot;Global Warming&quot;, or vice versa?&lt;/li&gt;&#xA;  &lt;li&gt;Is &quot;Climate Change&quot; a reiteration of an earlier theory, &quot;Global Warming&quot;?&lt;/li&gt;&#xA;  &lt;li&gt;Are these terms in fact synonymous?&lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In order,&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Vice versa.&lt;/li&gt;&#xA;&lt;li&gt;No.&lt;/li&gt;&#xA;&lt;li&gt;No.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&quot;Climate change&quot; (and its kin, &quot;climatic change&quot;) is a far older term than is &quot;global warming.&quot; The terms &quot;climate change&quot; / &quot;climatic change&quot; are and always have been the dominant terms used in the scientific literature (over &quot;global warming&quot;). Anthropogenic global warming is but one aspect of anthropogenic climate change, which in turn is but one aspect of climate science. In particular, increased global warming (above natural) is one of the climatic consequences of humans dumping very large amounts of greenhouse gases into the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since climate change is the older concept, climate change cannot have derived from &quot;global warming&quot;, and it is not a reiteration of an earlier theory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some references that show that &quot;climate change&quot; is an old term:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.jstor.org/stable/1883908?seq=1#page_scan_tab_contents&quot; rel=&quot;noreferrer&quot;&gt;Ellsworth Huntington (1917), &quot;Climatic change and agricultural exhaustion as elements in the fall of Rome,&quot; &lt;em&gt;The Quarterly Journal of Economics&lt;/em&gt; (1917): 173-208.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://books.google.com/books?hl=en&amp;amp;lr=&amp;amp;id=vPHHk2t1Tq4C&amp;amp;oi=fnd&amp;amp;pg=PA67&amp;amp;dq=climatic+change&amp;amp;ots=TfkZopKUYp&amp;amp;sig=yrj6ZZYsOtBppOQBJk_2Xjk_Id8#v=onepage&amp;amp;q=climatic%20change&amp;amp;f=false&quot; rel=&quot;noreferrer&quot;&gt;Richard Joel Russell (1941), &quot;Climatic change through the ages,&quot; &lt;em&gt;Climate and Man&lt;/em&gt;, U.S. Department of Agriculture: 67.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.cabdirect.org/abstracts/19560601984.html&quot; rel=&quot;noreferrer&quot;&gt;Edmund Schulman (1956), &quot;Dendroclimatic changes in semiarid America,&quot; University of Arizona Press, Tucson Arizona.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nasa.gov/topics/earth/features/climate_by_any_other_name.html&quot; rel=&quot;noreferrer&quot;&gt;NASA - What's in a Name? Global Warming vs. Climate Change&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;&lt;strong&gt;Update&lt;/strong&gt;&lt;br&gt;&#xA;There was a lot of discussion on this topic. That discussion may eventually vanish. The question ended up asking for references, lots and lots of references. I do not have the time or the inclination to do that. What I can do is supply links to sites that do supply those references:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.davidappell.com/EarlyClimateScience.html&quot; rel=&quot;noreferrer&quot;&gt;David Appell, &quot;Some Early and Important Works on Climate Science, Carbon Dioxide, and Human Influence.&quot;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.aip.org/history/climate/bibdate.htm&quot; rel=&quot;noreferrer&quot;&gt;American Institute of Physics, &quot;Bibliography by year: The Discovery of Global Warming.&quot;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.ipcc.ch/report/ar5&quot; rel=&quot;noreferrer&quot;&gt;Intergovernmental Panel on Climate Change, &quot;Fifth Assessment Report.&quot;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2016-02-24T19:38:36.723" LastActivityDate="2016-02-24T19:38:36.723" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="7565" PostTypeId="2" ParentId="7553" CreationDate="2016-02-24T02:13:28.023" Score="8" Body="&lt;p&gt;I see three issues to be considered and will address them in what I think is reverse order of importance:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) Cost: you have considered this with solar power and by trying to use mud to reduce infiltration through the lake bed. Fair enough, for now let's assume the scheme could be cost effective.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Negative impacts on the environment. You &lt;em&gt;will&lt;/em&gt; get infiltration of saline water to the ground, although you may be able to minimise it. Eventually that will recharge the groundwater or form an unconfined or perched aquifer on top of low-permeability sediments. My understanding is that the Nubian Aquifer is largely confined except in recharge areas far to the south. So the saline water may not affect it except over exceedingly long time frames. The Nubian Aquifer has extremely old water so even if it were to be contaminated with salt, it might take so long to reach irrigation areas that people wouldn't worry about it. After all, they are essentially mining the fresh water out and not trying to match sustainable yields. In some places the groundwater is saline and not usable already. But these are things that would have to be addressed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not sure that salt at the surface would be a significant problem. Much of Australia has ephemeral saline lakes at the surface that don't have major impacts (in my opinion) on the surrounding land when they are dry. But you are talking very large scale. I expect that the dry lake bed would stabilise with a sediment cover blowing in so salt dispersion would cease.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Would it work? I think it's a great idea but I'm skeptical. There are a lot of areas near the oceans where dew formation doesn't seem to produce significant amount of green vegetation. Well there are parts of Chile where dew is important in supporting the ecosystem, but that ecosystem is pretty unique and sparse. Not something that would support much human population. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I understand your question you are suggesting that the green vegetation would produce a feedback loop that promotes further dew or precipitation and becomes self sustaining. I can't say whether that could occur in some regions. If you look at the Great Artesian Basin of Australia, Lake Eyre and other very large lakes will fill with fresh water periodically and then go saline or even dry out. However, they haven't developed self-supporting vegetation, to my knowledge. The terrestrial plants rely on periodic rainfall due to storm tracks, generally from the west or north. If nothing else, thinking about it will teach you a lot about climate and weather. Hope this helps.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2016-02-24T02:13:28.023" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7566" PostTypeId="2" ParentId="7553" CreationDate="2016-02-24T08:01:08.513" Score="9" Body="&lt;p&gt;Nevada is 286,367 km² in area. With a conservative average evaporation of 2500 mm/yr in your desert, a lake of that size would evaporate 22686 m3/s. That is a flow larger than the average river discharge of the Nile. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see in the plot, the best price for pumping water to an elevation of only 50 m above the sea level is 0.131 \$/3.78 m3, so to pump 22k m3/s you need to pay 786 \$/s, or &lt;strong&gt;24 billion \$ per year&lt;/strong&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3JfMy.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3JfMy.jpg&quot; alt=&quot;Cost of pumping water&quot;&gt;The power cost ($/1000 Gal) per thousand gallons pumped for a pump with a BEP efficiency of 85 percent driven by a motor with an efficiency of 93 percent.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly, you can easily estimate that the power needed to pump (all parameters kept the same) is around 1.25 billion (1e9) Watts. With a 50% total efficiency, you would need around 200 last-generation aerogenerator monsters &lt;a href=&quot;https://www.youtube.com/watch?v=qS3CtSX8Eck&quot; rel=&quot;noreferrer&quot;&gt;like these&lt;/a&gt; to do it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only way to do this efficiently is by bringing water from a higher natural source. Some deserts in Egypt and Algeria lay below sea level, so bringing marine water to them would be cheap.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are many proposed scenarios to do very similar things: flooding the Siwa desert, &lt;a href=&quot;http://retosterricolas.blogspot.com/2010/01/mediterranean-distopia.html&quot; rel=&quot;noreferrer&quot;&gt;desiccating the Mediterranean&lt;/a&gt;... Some have already been &lt;a href=&quot;http://www.johnbohannon.org/NewFiles/Nile.pdf&quot; rel=&quot;noreferrer&quot;&gt;put in practice&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the key underlying question here is: &lt;em&gt;What for?&lt;/em&gt; The fact that something is big, cheap, and doable does not make it worthful. The environmental implications of these huge geoengineering projects are enormous and difficult to predict in detail. &lt;/p&gt;&#xA;" OwnerUserId="1379" LastEditorUserId="595" LastEditDate="2016-02-24T11:44:55.830" LastActivityDate="2016-02-24T11:44:55.830" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7567" PostTypeId="1" CreationDate="2016-02-24T09:06:15.483" Score="1" ViewCount="194" Body="&lt;p&gt;Serpentinite belongs to the serpentine group. This group of minerals are metamorphic minerals caused a special process called serpentinization.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Serpentinization created serpentinite on the Earth's deep sea floor. Serpentinite is paramagnetic which creates a magnetic field for the mineral.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While researching this unusual mineral scientists found microbes within its structure. After study scientists suggest that these microbes are the origins of life.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the connection  between the microbes and serpentinite?&lt;/p&gt;&#xA;" OwnerUserId="4617" LastEditorUserId="2570" LastEditDate="2016-05-23T23:32:49.757" LastActivityDate="2016-05-23T23:32:49.757" Title="Connection between microbes and serpentinite?" Tags="|ocean|mineralogy|paleontology|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7569" PostTypeId="2" ParentId="7567" CreationDate="2016-02-24T10:57:11.063" Score="9" Body="&lt;p&gt;The most common explanation for microbial activity in serpentinites is the exploitation of abiogentic hydrogen and methane formed during the serpentinisation process.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quoting the abstract of a recent authoritative review:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The process of serpentinization creates strongly reducing conditions and produces fluids that are highly enriched in molecular hydrogen and methane. Some microorganisms are able to exploit these compounds to gain metabolic energy and to generate biomass, leading to the development of biological communities based on chemical energy rather than photosynthesis. The abundance of chemical energy and favorable conditions for organic synthesis make serpentinites a strong candidate for the site of the origin of life on Earth, as well as a prime target in the search for life elsewhere in our Solar System.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;http://elements.geoscienceworld.org/content/9/2/129.short&quot;&gt;Serpentinites, Hydrogen, and Life&lt;/a&gt; (may be paywalled).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might also find this review interesting: &lt;a href=&quot;http://www.minsocam.org/MSA/RIM/RiMG075/RiMG075_Ch18.pdf&quot;&gt;Serpentinization, Carbon, and Deep Life&lt;/a&gt; (should be free to access).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These two papers present the current thinking in this subject.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-02-24T10:57:11.063" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7570" PostTypeId="1" AcceptedAnswerId="7571" CreationDate="2016-02-24T12:35:27.110" Score="2" ViewCount="400" Body="&lt;p&gt;I saw this line today in a NWS weather alert:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;ACCUMULATIONS...A FEW HUNDREDS OF ICE ACCRETION.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Is this standard terminology?&#xA;Does &quot;hundreds (of)&quot; somehow refer to a unit of measure, or&#xA;is there a (likely or standard) unit of measure implied or missing here?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://alerts.weather.gov/cap/wwacapget.php?x=MA1255EAFEBC38.WinterWeatherAdvisory.1255EB001010MA.BOXWSWBOX.18aa678bad1893fa8f6667c193e56ef4&quot; rel=&quot;nofollow&quot;&gt;http://alerts.weather.gov/cap/wwacapget.php?x=MA1255EAFEBC38.WinterWeatherAdvisory.1255EB001010MA.BOXWSWBOX.18aa678bad1893fa8f6667c193e56ef4&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5525" LastActivityDate="2016-02-24T13:07:34.267" Title="Definition of &quot;hundreds of ice accretion&quot;" Tags="|meteorology|terminology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7571" PostTypeId="2" ParentId="7570" CreationDate="2016-02-24T13:07:34.267" Score="2" Body="&lt;p&gt;I think that it's referring to hundredths of an inch, and &quot;hundreds&quot; is a typo for &quot;hundredths&quot;. &lt;a href=&quot;https://www.faa.gov/other_visit/aviation_industry/airline_operators/airline_safety/info/all_infos/media/2008/info08024.pdf&quot; rel=&quot;nofollow&quot;&gt;This FAA information sheet&lt;/a&gt; says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;All ice accretion amounts will be reported to the nearest one-hundredth of an inch (0.01 in.). An example of a 1, 3, 6-hour ice accretion remark would be: “I1010 I3015 I6022.” This translates to 0.10 inches of ice in the last hour, 0.15 inches of ice in the last 3 hours, and 0.22 inches of ice in the last 6 hours.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This also matches the terminology used in some other weather reports, such as &lt;a href=&quot;https://climate.ncsu.edu/climate/winter_wx/database_details.php?e=605&quot; rel=&quot;nofollow&quot;&gt;this one&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Ice accretion was light, generally only a few hundredths of an inch...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="94" LastActivityDate="2016-02-24T13:07:34.267" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7572" PostTypeId="1" AcceptedAnswerId="7579" CreationDate="2016-02-24T15:58:10.637" Score="3" ViewCount="113" Body="&lt;p&gt;I would like to simulate the trajectory of a weather balloon in an altitude of 12 to 20 km.&#xA;For this I would like to know how the velocity-field (i.e. wind-speed and direction as a function of position and time) looks like and how constant it is in the time and space domain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there some publicly available data about air-circulation in the stratosphere? Or do you have an idea how to generate test-data for my simulation?&lt;/p&gt;&#xA;" OwnerUserId="5526" LastEditorUserId="595" LastEditDate="2016-07-25T11:34:12.947" LastActivityDate="2016-07-25T11:34:12.947" Title="How does the air-circulation in the lower stratosphere look like?" Tags="|meteorology|wind|open-data|stratosphere|simulation|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7573" PostTypeId="1" AcceptedAnswerId="7574" CreationDate="2016-02-24T17:12:55.593" Score="2" ViewCount="134" Body="&lt;p&gt;I just read the article &lt;a href=&quot;http://www.iflscience.com/space/largest-meteor-years-fell-over-atlantic&quot; rel=&quot;nofollow&quot;&gt;Meteor Explosion Over the Atlantic&lt;/a&gt; and it states that &quot;Data released by NASA shows that the meteor released an energy equivalent to 12,000 tonnes (13,000 tons) of TNT, and it was moving at over 15.5 kilometers per second (9.6 miles per second).&quot;  Awesome.  I understand that part.  What I don't necessarily understand is how an explosion happened if the meteor is disintegrating.  Is it when the meteor enters the atmosphere, or is there some reaction that I'm missing.  Thanks!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit - My understanding is that it caused an explosion after entering the atmosphere prior to hitting the ground. My question is how that is possible? I understand the concept of the atmosphere and ground would cause an explosion, but how is it possible while in mid-air?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS - Couldn't figure out which Overflow I should place this question in.  This one sounded the best.  Thanks!&lt;/p&gt;&#xA;" OwnerUserId="5527" LastEditorUserId="5527" LastEditDate="2016-02-24T19:28:52.013" LastActivityDate="2016-02-24T19:28:52.013" Title="Meteor Explosion" Tags="|meteorite|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7574" PostTypeId="2" ParentId="7573" CreationDate="2016-02-24T18:36:53.230" Score="3" Body="&lt;p&gt;Let me see if I got your question right: You want to understand what causes the meteorite to explode?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's explain that in an understandable way.&#xA;You know that in space we have nearly an absolute vacuum thus no friction between the meteor and other particles, that's the reason it can achieve such a high velocity without melting down or exploding.Upon entering earth's atmosphere the particle density around the meteorite rises incredibly fast due to its velocity. The meteorite gets a certain resistance dependant on it's speed and size. That's like going out on a biketrip. The faster you go the more air resistance you can feel, even more so when wearing a thick jacket for example, which means a higher surface to attack.&#xA;So, the meteor entered the atmosphere and collided with it. Dependant on it's density, hardness and overall energy three things can happen: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;It's dense and hard enough to withstand the collision but will have such high increase in thermal energy due to the friction, that it starts to melt down/evaporate &quot;slowly&quot; while moving forward&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;It has such a high energy and/or small density and hardness that the energy set free is high enough to let the meteorite evaporize or explode directly upon crashing with the atmosphere..&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;It withstands the thermal and mechanical energy arising and keeps on flying&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Of course the meteorite loses energy during that process and will slow down. Note that the energy is not lost but transformed. The air/rocks around the impact will have an increase in energy causing them to thermally expanse extremely fast thus creating a shockwave. This part is what you could call the main explosion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The explosion of the rock itself is also well explained with this:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;With the meteor moving at this speed, there is a lot of heat generated (compression, as well as friction/viscosity). This boils the meteor (many meteors contain ice or dry ice), leading to a buildup in pressure. If the boiling happens too quickly, the meteor will explode.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The friction increases the farther the meteorite moves so the energy will get higher and higher until the above mentioned happens. This would be a &quot;non-contact-explosion&quot;..&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also the Atmosphere consists of more than one layer of different densities (lower layer, higher density) so the whole process of crashing into a wall of higher density happens several times before finally reaching earth's surface.&#xA;In case 3 the meteorite will keep flying until hitting a harder surface, that would be our earth in this case.&#xA;The earth is big and hard enough to absorb the energy from the impact. So the meteorite crashes and will then release it's entire internal energy, since it can't move forward anymore, which in most cases is high enough to let it explode or evaporize.. In case of a very small meteorite it might just crash without exploding, because it can withstand the energy, but will still create an impact crater.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the process when hitting the atmosphere or earth's surface is the same: A change in density causes the meteorite to release energy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the end a little metaphor for even better understanding:&#xA;You take a rock and throw it against a wall.. It crashes and will maybe create a little crater but it won't explode.. Now you take the same rock and throw it as hard as you can so it has more energy.. when hitting the wall again it will release all it's energy and explode.. Due to the walls hardness it can't move through it, of course unless the rock is is harder than the wall and fast enough.. That would be the equivalent to the meteorite hitting earth.&#xA;Try the same mind experiment with the same rock being thrown at water, which would be the equivalent to the meteorite hitting the atmosphere, which can be seen as a fluid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Summarized:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The meteorite crashes into a higher density wall and the set free energy causes it to disrupt, like a rock thrown at a wall&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The build up pressure of fluids within the meteorite causes it to explode&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;PS: So the release of energy when colliding is what causes the explosion whether it disintegrates or not. The equivalent to 15.000 tons of TNT represents the internal energy of the meteorite that's set free.&lt;/p&gt;&#xA;" OwnerUserId="5274" LastEditorUserId="5274" LastEditDate="2016-02-24T19:12:15.357" LastActivityDate="2016-02-24T19:12:15.357" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7575" PostTypeId="2" ParentId="7573" CreationDate="2016-02-24T19:14:57.773" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;What I don't necessarily understand is how an explosion happened if the meteor is disintegrating.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That disintegration is not a gradual thing. Stony meteors are only loosely held together. That's fine for an object in space. It's not fine when the meteor hits the atmosphere. Once a meteor starts disintegrating, the disintegration cascades very, very quickly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That &quot;Rapid Unscheduled Disassembly&quot; of the meteor &lt;strong&gt;is&lt;/strong&gt; the explosion. Instead of one object with a few pieces flying off, there are hundreds, then thousands, then tens of thousands of objects, all in short order. The surface area grows hugely, making those myriad chunks dump their kinetic energy into the atmosphere in a very short period of time. &lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2016-02-24T19:14:57.773" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7576" PostTypeId="2" ParentId="7562" CreationDate="2016-02-24T20:22:13.710" Score="4" Body="&lt;p&gt;&lt;strong&gt;&lt;em&gt;Note:&lt;/strong&gt; As the OP, it's not quite fair to say this is &quot;my&quot; answer, but a synthesis of the many comments provided. -- Thank you.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Question Restatement:&lt;/h1&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Given the many representations of &quot;Global Warming&quot; and &quot;Climate Change&quot; - what are the &quot;Official Definitions&quot; being used in this debate?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;How these terms are used by the IPCC; and &lt;/li&gt;&#xA;&lt;li&gt;The senses of these terms used by skeptics -- especially in the written letters voicing concerns by other Scientists?&lt;/li&gt;&#xA;&lt;li&gt;Are people actually talking about different things? The same things? &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Source:&lt;/em&gt;&lt;/strong&gt; &lt;a href=&quot;http://www.ipcc.ch/report/ar5/wg1/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate Change 2013: The Physical Science Basis&lt;/a&gt;&#xA;&lt;em&gt;(Used throughout.)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;1. What is Anthropogenic Climate Change?&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;As the Original Poster, I had honestly never heard of &quot;Anthropogenic&quot;. Understanding what this means clarified the terms, for me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The context of the objections, and their usage of terms, was explicitly in the context of &quot;policy&quot; and &quot;responses&quot;, specifically the significance of &quot;human pollution&quot;, that is: &lt;strong&gt;&lt;em&gt;Anthropogenic Climate Impact&lt;/em&gt;&lt;/strong&gt; - &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Paleoclimate Archives, Chapter 5, pg. 392&lt;/strong&gt; - &lt;strong&gt;&lt;em&gt;Anthropogenic (human-produced) factors&lt;/em&gt;&lt;/strong&gt;, on the other hand, include changes in the concentrations of greenhouse gases, and emissions of visible air pollution (aerosols) and other substances &lt;strong&gt;&lt;em&gt;from human activities&lt;/em&gt;&lt;/strong&gt;. ‘Internal variability’ refers to fluctuations within the climate system, for example, due to weather variability or phenomena like the El Niño-Southern Oscillation, &lt;em&gt;(Chapter 5. pg. 392)&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Statistical Use of &quot;Anthropogenic&quot;:  &lt;a href=&quot;https://books.google.com/ngrams/graph?content=anthropogenic%2Cclimate+change%2Cglobal+warming%2Cgreenhouse+effect%2Cgreenhouse+gas&amp;amp;year_start=1970&amp;amp;year_end=2008&amp;amp;corpus=15&amp;amp;smoothing=3&amp;amp;share=&amp;amp;direct_url=t1%3B%2Canthropogenic%3B%2Cc0%3B.t1%3B%2Cclimate%20change%3B%2Cc0%3B.t1%3B%2Cglobal%20warming%3B%2Cc0%3B.t1%3B%2Cgreenhouse%20effect%3B%2Cc0%3B.t1%3B%2Cgreenhouse%20gas%3B%2Cc0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google Books Ngram Viewer: 1970 - 2008 Statistical use of Anthropogenic, Climate Change, Global Warming, Greenhouse Effect, Greenhouse Gas.&quot;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;2. Global Warming - A Discussion of Greenhouse Gasses and Radiative Forcing:&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Although &lt;strong&gt;&lt;em&gt;Global Warming&lt;/em&gt;&lt;/strong&gt; &lt;a href=&quot;http://www.nasa.gov/topics/earth/features/climate_by_any_other_name.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;can be used interchangeably with Climate Change, NASA 12.05.08&lt;/a&gt;, Global Warming is in reference to &lt;strong&gt;&lt;em&gt;Radiative Forcing&lt;/em&gt;&lt;/strong&gt; and the &lt;strong&gt;&lt;em&gt;Greenhouse Effect&lt;/em&gt;&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Global Warming Potential (GWP), pg. 1455)&lt;/strong&gt; - An index, based on radiative&#xA;  properties of &lt;strong&gt;&lt;em&gt;greenhouse gases&lt;/em&gt;&lt;/strong&gt;, measuring the &lt;strong&gt;&lt;em&gt;radiative forcing&lt;/em&gt;&lt;/strong&gt; following a pulse emission of a unit mass of a given greenhouse gas in the presentday atmosphere integrated over a chosen time horizon, relative to that of &lt;strong&gt;&lt;em&gt;carbon dioxide&lt;/em&gt;&lt;/strong&gt;.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;strong&gt;Radiative forcing, (Glossary, pg. 1460)&lt;/strong&gt; - Radiative forcing is the change in the net, downward minus upward, radiative flux (expressed in W m–2) at the tropopause or top of atmosphere &lt;strong&gt;&lt;em&gt;due to a change in an external driver of climate change&lt;/em&gt;&lt;/strong&gt;, such as, for example, a change in the concentration of carbon dioxide or the output of the Sun. &lt;strong&gt;&lt;em&gt;Sometimes internal drivers are still treated as forcings even&lt;/em&gt;&lt;/strong&gt; though they result from the alteration in climate, for example aerosol or greenhouse gas changes in paleoclimates. &lt;em&gt;(See Chapter 8, Radiative Forcing.)&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;h1&gt;3. Climate Change - Persistent Change Caused by Internal Processes or External Forcings:&lt;/h1&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Climate change, (Glossary, pg. 1450)&lt;/strong&gt; - Climate change refers to a change in the state of the climate that can be identified (e.g., by using statistical tests) by changes in the mean and/or the variability of its properties, and that persists for an extended period, typically decades or longer. &lt;strong&gt;&lt;em&gt;Climate change may be due to natural internal processes or external forcings&lt;/em&gt;&lt;/strong&gt; such as modulations of the solar cycles, volcanic eruptions and persistent anthropogenic changes in the composition of the atmosphere or in land use. ...&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;...&lt;strong&gt;Framework Convention on Climate Change (UNFCCC), Article 1&lt;/strong&gt; - Climate change as ... ‘a change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods’. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The UNFCCC thus &lt;strong&gt;&lt;em&gt;makes a distinction between climate change attributable to human activities&lt;/em&gt;&lt;/strong&gt; altering the atmospheric composition, &lt;strong&gt;&lt;em&gt;and climate variability attributable to natural causes&lt;/em&gt;&lt;/strong&gt;. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;strong&gt;Abrupt Climate Change, Section 12.5.5.1, pg. 1114&lt;/strong&gt; - This report adopts the definition of abrupt climate change used in Synthesis and Assessment Product 3.4 of the U.S. Climate Change Science Program CCSP (CCSP, 2008b). We define abrupt climate change as a large-scale change in the climate system that takes place over a few decades or less, persists (or is anticipated to persist) for at least a few decades, and causes substantial disruptions in human and natural systems, &lt;em&gt;(pg. 1448, etc.)&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;h1&gt;4. Relationship Between Global Warming and Radiative Forcing:&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Global Warming is associated with the &lt;strong&gt;&lt;em&gt;Greenhouse Effect&lt;/em&gt;&lt;/strong&gt; and &lt;strong&gt;&lt;em&gt;Radiative Forcing&lt;/em&gt;&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Drivers of Climate Change&lt;/strong&gt; - Natural and anthropogenic substances and processes that alter the Earth’s energy budget are drivers of climate change, (pg. 13).&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;strong&gt;From Forcing to Attribution of Climate Change (Chapters 8, 9 and 10), (Chap. 1, pg. 151)&lt;/strong&gt; - In these chapters, all the information on the different drivers (natural and anthropogenic) of climate change is collected, expressed in terms of RF &lt;em&gt;[radiative forcing]&lt;/em&gt;, and assessed (Chapter 8). As part of this, the science of metrics commonly used in the literature to compare radiative effects from a range of agents (Global Warming Potential, Global Temperature Change Potential and others) is covered.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="5521" LastEditorUserId="5521" LastEditDate="2018-01-31T23:10:17.310" LastActivityDate="2018-01-31T23:10:17.310" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7577" PostTypeId="1" CreationDate="2016-02-24T21:19:00.567" Score="1" ViewCount="236" Body="&lt;p&gt;I'm looking for a formula, either precise or an approximation (it's for a video game so it's ok to have somewhat rough numbers), that determines heat retained from the sun by an atmosphere, based on its density and composition (specifically CO2 composition, but bonus points if it factors other things in too).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does such a formula exist?  Or if not, are there any rule-of-thumb sort of things I could use for estimating &quot;If an atmosphere doubles in density, its heat will rise by X percent&quot; or &quot;If you replace half the CO2 in the atmosphere with O2, your heat will drop by Y percent&quot;, etc?&lt;/p&gt;&#xA;" OwnerUserId="3357" LastEditorUserId="5214" LastEditDate="2016-02-27T14:34:59.433" LastActivityDate="2016-02-27T14:34:59.433" Title="Is there a formula for heat retained by an atmosphere, based on density and composition?" Tags="|meteorology|atmosphere|climate-change|temperature|atmosphere-modelling|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7578" PostTypeId="2" ParentId="7577" CreationDate="2016-02-24T23:33:30.470" Score="1" Body="&lt;p&gt;Earth's atmosphere is composed of a number of layers: troposphere, stratosphere, mesosphere, thermosphere and exosphere, ascending in order from the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each layer has different characteristics and within each layer the temperature profile is different. The red line in the following &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;US standard atmosphere graph&lt;/a&gt; shows the temperature profile of the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The temperature profile is complex and is not related to air density (the amber line on the graph) above the tropopause. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are higher temperatures on the Earth's surface and at the stratopause but low temperatures at the tropopause and mesopause.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/x6BHo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/x6BHo.png&quot; alt=&quot;Atmosphere Profile&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for carbon dioxide, it is &lt;a href=&quot;http://courses.washington.edu/pcc587/readings/atmosphericstructure.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;fairly well mixed in the atmosphere&lt;/a&gt;, particularly at altitude. &lt;a href=&quot;http://www.jpl.nasa.gov/news/news.php?release=2008-189&quot; rel=&quot;nofollow noreferrer&quot;&gt;Concentrations of carbon dioxide&lt;/a&gt; vary laterally near the Earth's surface, with the concentrated regions occurring in areas of major human activity, as can be seen from the NASA produced picture below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/e7cpw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/e7cpw.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-02-24T23:33:30.470" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7579" PostTypeId="2" ParentId="7572" CreationDate="2016-02-25T00:21:08.313" Score="1" Body="&lt;p&gt;&lt;a href=&quot;http://www.goes-r.gov/downloads/AMS/AMS2015/January%208/Joint%20Session%2019/Cubesat%20FTS%20for%203D%20Winds%20AMS%20J19.4.pdf&quot; rel=&quot;nofollow&quot;&gt;This presentation&lt;/a&gt; mentions &quot;Atmospheric Motion Vectors (AMVs)&quot;, and specifically mentions a number of AMVs, which separately cover the globe (GOES AMVs ±60N, plus polar AMVs from MODIS/AVHRR/VIIRS, and a combined product from UW CIMSS) but says that are all only 3 layers. That presentation is talking about producing a more global, higher resolution product, but it's only a year old, so I'd guess the data isn't available yet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the &lt;a href=&quot;http://tropic.ssec.wisc.edu/misc/winds/info.winds.gridded.html&quot; rel=&quot;nofollow&quot;&gt;UW CIMSS AMV page&lt;/a&gt; says that their datasets have 13 layers, so maybe it is suited for what you need. The data is gap-filled with modelled data.&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2016-02-25T00:21:08.313" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7582" PostTypeId="2" ParentId="7567" CreationDate="2016-02-25T23:54:43.847" Score="3" Body="&lt;p&gt;The microbes are not &quot;in&quot; serpentinite; serpentinite is a rock formed by hydrothermal alteration of mafic and ultramafic rocks resulting in the formation of magnetite and the release of hydrocarbon compounds as fluids and gasses (methane, CO2). The microscopic life that takes advantage of the conditions formed by serpentinisation does so in the deep waters of the ocean where it takes place. Mixing of these heavily reduced fluids with seawater creates conditions where chemolithoautotrophic can thrive. The fossil assemblages exist in calcite and brucite veins within the subseafloor lithology, but not within the serpentinised areas.&lt;/p&gt;&#xA;" OwnerUserId="496" LastActivityDate="2016-02-25T23:54:43.847" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7583" PostTypeId="1" CreationDate="2016-02-26T00:08:00.373" Score="8" ViewCount="353" Body="&lt;p&gt;I feel like I am missing something blindingly simple, but I am curious about something.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We are given the velocity of a P-wave as $v_{p} = \sqrt{(K+\frac{4}{3}μ)/ρ}$.  So I am to understand conceptually that as density increases, the velocity of the P-wave also increases.  However looking at the equation would indicate a lower velocity with increased density.  Is it just a matter of the bulk and shear modulus' increasing at a more rapid rate than density as you travel through lower depths?&lt;/p&gt;&#xA;" OwnerUserId="5534" LastEditorUserId="20" LastEditDate="2016-03-09T21:09:47.390" LastActivityDate="2016-03-09T21:11:42.637" Title="Regarding velocity of P/S-waves" Tags="|geophysics|seismology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7584" PostTypeId="1" AcceptedAnswerId="7588" CreationDate="2016-02-26T01:02:11.057" Score="9" ViewCount="716" Body="&lt;p&gt;It is just curiosity that forced me to ask this question. At some point in time, if we can't control global $\sf{CO_2}$ emissions, temperature will increase until a tipping point and it will be a complete catastrophe. However, if we could prepare ourselves through geo-engineering (e.g. carbon removal, blocking solar radiation), then we may return the temperature back to normal. I am not saying that we have to experiment with mother Earth, but if we may do weather-engineering experiments in controlled labs just like the Large Hadron Collider(LHC), we may some day be able to save the planet from catastrophe. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, my question is, how bad does geo-engineering go as far as controlled experiments done in totally isolated labs? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In NWP models, it is mostly possible to control the evolution of $\sf{CO_2}$, solar radiation, moisture, temperature etc. Given the current computation power is better than in the past and will most likely be better in the future, once we have calibrated and validated those climate/weather models, can we use them to fight extremes of weather like floods, drought, hurricanes and all other wind storms?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The accuracy of current weather predictions is better for forecasts 5-10 days ahead. So, this may give enough time to do controlled simulations before and after our intervention. Based on that we may act on to, for example, increase precipitation (e.g. through controlled spraying of condensation nuclei) where there is drought, hit and disperse hurricanes or change their directions before they hit and damage cities etc. How wrong can one be to think like that? &lt;/p&gt;&#xA;" OwnerUserId="4877" LastEditorUserId="4877" LastEditDate="2017-09-19T20:29:12.573" LastActivityDate="2023-11-01T13:41:51.300" Title="How bad is geo-engineering?" Tags="|meteorology|geophysics|planetary-science|atmosphere-modelling|geoengineering|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7585" PostTypeId="2" ParentId="7384" CreationDate="2016-02-26T05:15:12.887" Score="1" Body="&lt;p&gt;You need to examine the assumption that it &quot;stabilized&quot;. Rather (and simplistically, of course), the Milankovitch cycle en.wikipedia.org/wiki/Milankovitch_cycles moved from a stable Ice Age regime to an interglacial one.  Absent the current human interference, it would (IIRC, anyway) continue the interglacial for some tens of thousands of years, before entering another ice age.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nor does the end of the last Ice Age really correlate with the rise of large civilizations, since there was about a 5-6K year gap.  IOW, roughly as long from the end of the Ice Age to the first civilizations, as from them to the present.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2016-02-26T05:15:12.887" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7586" PostTypeId="2" ParentId="7567" CreationDate="2016-02-26T06:29:00.667" Score="-5" Body="&lt;p&gt;Serpentinites is paramagnetic,And certain microbes known to be paramagnetic also, these microbes are atracted to magnetic field lines.These microbes thrive in evironments where little to no oxygen is present.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Olivine morphs into Serpentinite due to serpentization process, These minerals are classified as Metamorphic minerales serpentine means &quot;To Change&quot; in Greek.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Olivine is documented to be in abundance on the planet Mars as well as Methane which only means the serpentinization process is taking place, the energy needed to support biotic and biological organisms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;China's Jade Rabbit moon mission documented they have discovered&#xA;discovered Olivine, Unkown to be present on Earths moon.&lt;/p&gt;&#xA;" OwnerUserId="4617" LastEditorUserId="4617" LastEditDate="2016-02-27T08:48:46.573" LastActivityDate="2016-02-27T08:48:46.573" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7587" PostTypeId="1" CreationDate="2016-02-26T06:48:38.603" Score="4" ViewCount="533" Body="&lt;p&gt;I want to generate synthetic fault slip data using a known stress tensor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am using a rotation matrix to get the orientation of the principal stress axes, and rotating the tensor [1 0 0, 0 phi 0, 0 0 0] to get a reduced stress tensor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then I have to create (strike, dip) of the plane and (trend, plunge) of the lineations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Right now, my equations look like this-&lt;/p&gt;&#xA;&#xA;&lt;p&gt;T = [1 0 0, 0 phi 0, 0 0 0]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;R = rotation matrix (each row of R will contain the direction cosines of the principal stress axes)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reduced tensor (S) = R.T.(R_transpose)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Randomly generate a fault plane (strike and dip), get its normal vector N.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Stress Vector = S.N&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using Normal Vector and Stress Vector, get the component of stress vector along the fault plane, i.e., the shear stress component.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Get the trend and plunge of the shear stress component.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Right now, I am unable to differentiate between normal and reverse faults by only varying the stress tensor. Do I also have to change the trend, plunge for them?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I need the equations for implementing this on a computer program.&lt;/p&gt;&#xA;" OwnerUserId="3164" LastActivityDate="2016-02-26T06:48:38.603" Title="How to differentiate between normal and reverse fault, given a stress tensor?" Tags="|geology|structural-geology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7588" PostTypeId="2" ParentId="7584" CreationDate="2016-02-26T11:34:20.420" Score="18" Body="&lt;p&gt;The bad part about geo-engineering are the &lt;em&gt;unknown unknowns&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Our climate models are wrong.  &lt;a href=&quot;https://en.wikiquote.org/wiki/George_E._P._Box&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;All models are wrong, but some are useful.&lt;/em&gt;&lt;/a&gt;.  Our models are useful, but not quite useful enough to trust them when they tell us massively spraying stuff into the stratosphere or the oceans is mostly harmless.  Our models can't properly reproduce our current climate.  They agree about some trends, but there's lots of stuff that they're missing.&lt;/p&gt;&#xA;&lt;p&gt;We used to use lots of toxic chemicals in our fridges.  That was a bad idea, so we found &lt;a href=&quot;https://en.wikipedia.org/wiki/Chlorofluorocarbon&quot; rel=&quot;nofollow noreferrer&quot;&gt;some stuff that wasn't toxic&lt;/a&gt;.  Great, no?  Decades later, scientists realised this was destroying ozone above Antarctica.  At first the measurements were rejected because they didn't make sense.  Contrasted with our understanding of the atmosphere, and why would ozone suddenly disappear anyway?  Then they were replaced by gases that don't destroy ozone, but that have enormous greenhouse gas potential (although the latter was almost certainly not a surprise).&lt;/p&gt;&#xA;&lt;p&gt;Our climate system is complex.  Very complex.  Mess with one of the symptoms, and who knows what side effects are going to be?  It's a risk that we cannot quantify, and those are probably the scariest risks out there.  If even with stuff that doesn't seem remotely connected to each other (fridge coolants and ozone) we almost messed up &lt;em&gt;very&lt;/em&gt; seriously, who is to say actively messing with our atmosphere or ocean isn't going to have nasty unintended consequences?&lt;/p&gt;&#xA;&lt;p&gt;Better than offsetting one set of geoengineering (deforestation, ocean acidification, enhanced GHG emissions) with another equally radical one, it might be safer — from a risk management point of view — to try to not do any geoengineering at all.  Certainly as long as our understanding of climate is just starting.&lt;/p&gt;&#xA;&lt;p&gt;To borrow an analogy from medicine: preventing is better than curing.  Patients are sometimes prescribed medicine where the side-effects are so bad that they're almost lethal by themselves, but only when the patient is surely terminally ill, so there is &amp;quot;nothing to lose&amp;quot;.  We do have a lot to lose on Earth.&lt;/p&gt;&#xA;&lt;p&gt;Note that weather models are initial value problems and climate models solve boundary value problems, so mathematically speaking, the two are completely different.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2023-11-01T13:41:51.300" LastActivityDate="2023-11-01T13:41:51.300" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="7590" PostTypeId="2" ParentId="7584" CreationDate="2016-02-26T17:14:14.047" Score="8" Body="&lt;p&gt;Seconding eveything that @gerrit mentioned.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, another major problem with geo-engineering is that once we've started these processes and essentially borrowed time to offset mitigation measures, we'll have put ourselves in a situation where these measures will need to be continued almost indefinitely, regardless of the risks of negative side effects of geo-engineering to begin with (ie: chemical intrusions, biological system degradation, geopolitical concerns). Present climate models suggest that if we were to engage in climate engineering and then remove these after several years, warming rates will come back with force (&lt;a href=&quot;http://iopscience.iop.org/article/10.1088/1748-9326/4/4/045103&quot;&gt;http://iopscience.iop.org/article/10.1088/1748-9326/4/4/045103&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="5536" LastActivityDate="2016-02-26T17:14:14.047" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7592" PostTypeId="2" ParentId="7583" CreationDate="2016-02-26T20:48:49.387" Score="9" Body="&lt;p&gt;That is not a silly question! And your intuition is correct: As you bury and compact a sedimentary rock, its porosity will decrease, so its density increases. But we also see that its velocity tends to increase. This appears contrary to what that equation shows.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, as you bury the rock and decrease its porosity, you are simultaneously increasing the rock's effective stiffness (bulk and shear moduli). And yes, this effect overwhelms the density effect so the outcome is a faster P-wave velocity. So even though the derivation of this equation from continuum mechanics tells us that stiffness and density are independent parameters, &lt;a href=&quot;http://www.ipt.ntnu.no/pyrex/stash/GPY00770.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;they seldom are in nature&lt;/a&gt;. Most geological scenarios where density would increase, also raise the effective stiffness of the rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But here is an example where this is not the case. Imagine you have sandstone between two shales. The sandstone has some porosity and it is completely filled with brine. If that exact same sandstone (i.e. holding everything else constant) is now filled with gas instead of brine, its Bulk modulus will go down by a lot and Density will also go down but by less. However, &lt;a href=&quot;http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.386.5687&amp;amp;rep=rep1&amp;amp;type=pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;according to Gassmann's equations, the Shear modulus will stay constant&lt;/a&gt;. So the P-wave velocity goes down because the Bulk modulus effect overwhelms the Density effect and the Shear modulus doesn't change. But now consider the S-wave velocity whose equation is $v_s = \sqrt{μ/ρ}$. In this case there is no Bulk modulus to overwhelm the density and so the S-wave velocity will actually go up by a small amount when the rock is saturated with gas. This is purely a density effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nZc9U.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nZc9U.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This effect is commonly observed in hydrocarbon exploration where they have drilled a well into a sandstone that is full of water, but then go up dip and find something like an anticline where the same sandstone is now full of gas.&lt;/p&gt;&#xA;" OwnerUserId="4636" LastEditorUserId="20" LastEditDate="2016-03-09T21:11:42.637" LastActivityDate="2016-03-09T21:11:42.637" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7593" PostTypeId="1" AcceptedAnswerId="7596" CreationDate="2016-02-27T00:38:04.020" Score="4" ViewCount="2552" Body="&lt;p&gt;I can not really find a definition, not even in a geologic dictionnary: What are articulate (resp. inarticulate) shells?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To be more specific, the term is related to tsunami deposits (tsunamite).&lt;/p&gt;&#xA;" OwnerUserId="4784" LastEditorUserId="87" LastEditDate="2016-03-19T09:30:44.327" LastActivityDate="2016-03-19T09:30:44.327" Title="What are 'articulate shells'?" Tags="|geology|paleontology|stratigraphy|geomorphology|tsunami|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7594" PostTypeId="5" CreationDate="2016-02-27T11:30:42.453" Score="0" Body="&lt;p&gt;Different &lt;a href=&quot;http://www.ecmwf.int&quot; rel=&quot;nofollow&quot;&gt;ECMWF&lt;/a&gt; re-anlysis products exist (ERA-40, ERA-Interim, etc.). Hence, it might be important to specify the exact re-anlysis data set in the question.&lt;/p&gt;&#xA;" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2016-02-28T08:08:52.257" LastActivityDate="2016-02-28T08:08:52.257" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7595" PostTypeId="4" CreationDate="2016-02-27T11:30:42.453" Score="0" Body="Questions about ECMWF re-analysis" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2016-02-28T03:41:09.653" LastActivityDate="2016-02-28T03:41:09.653" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7596" PostTypeId="2" ParentId="7593" CreationDate="2016-02-27T16:22:09.513" Score="6" Body="&lt;p&gt;If I remember correctly from my intro to paleo class, the terms articulate and inarticulate refer to a classification of brachiopods depending on the nature of their hinge. Articulate brachiopods have something like interlocking hinges (like a door hinge) made from serrated (or tooth like) parts of the shell. On the other hand, inarticulate brachiopods hold their shells together using only their muscles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This means that the upper and lower shells of an inarticulate brachiopod will separate after it dies and its muscles decay. However, the shells on an articulate one will pretty much hold together unless a very strong mechanical force is applied. I don't know much about tsunami deposits, but this may have something to with that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not sure if this terminology extends to other phyla like molluscs, but I remember it from brachipods.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And here's a little picture because pictures make everything better.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PRkTO.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PRkTO.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this helps!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-Antonio&lt;/p&gt;&#xA;" OwnerUserId="4636" LastActivityDate="2016-02-27T16:22:09.513" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7597" PostTypeId="2" ParentId="7572" CreationDate="2016-02-27T17:29:22.743" Score="0" Body="&lt;p&gt;I have also found these maps: &lt;a href=&quot;http://earth.nullschool.net/&quot; rel=&quot;nofollow&quot;&gt;http://earth.nullschool.net/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is a nice visualization of winds at different elevations (from surface up to 10hPa).&lt;/p&gt;&#xA;" OwnerUserId="5526" LastActivityDate="2016-02-27T17:29:22.743" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7598" PostTypeId="2" ParentId="4541" CreationDate="2016-02-27T23:57:23.393" Score="2" Body="&lt;p&gt;It depends on what your starting information about your seismic data is. For example, if you know that your data contains an impulsive (minimum phase) source wavelet (i.e. the acquisition source was dynamite or a big ol' hammer, or some other impulsive source, and has not been modified) then you can apply the workflow of txpaulm or use spiking deconvolution. But realize that you are making an assumption about the shape of your wavelet's phase spectrum, which is a very good assumption most of the time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you don't want to make the minimum phase assumption for your wavelet (i.e. you think you have a mixed phase wavelet), you will need to make some other assumption or incorporate some other piece of information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A very popular method for estimating a mixed phased wavelet is that of &lt;a href=&quot;https://spiral.imperial.ac.uk/bitstream/10044/1/1443/1/WaldenWhite98.pdf&quot; rel=&quot;nofollow&quot;&gt;Walden and White (1998)&lt;/a&gt;. They incorporate additional information from a reflectivity series calculated at a well and then find the impulse response filter that best predicts (in the least squares sense) the seismic data extracted along the well path.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The trick here is that you are assuming that you know the velocity function (time-depth curve) along the well to correctly compare the well's calculated reflectivity series (in depth) with the extracted seismic data (in time). Errors in the time-depth curve will propagate into your extracted wavelet. What you can do is to first approximate the real wavelet with a simple zero-phase phase wavelet extracted from the autocorrelation of the seismic data (or you can use a Ricker wavelet of a reasonable dominant frequency if you want) and make a synthetic seismogram at the well. Then modify the time-depth relation along the well path (i.e. stretch and squeeze your synthetic) until your well is kinda-sorta fitting. Then go back and extract a better constant-phase wavelet (no more Ricker) through autocorrelation and try to modify the constant phase while simultaneously tweaking the time-depth curve along the well. You should already be close the right time-depth curve but this will get you pretty damn close to the answer. Once you are happy with the position of your synthetic with respect to the seismic data, then you can apply the method of &lt;a href=&quot;https://spiral.imperial.ac.uk/bitstream/10044/1/1443/1/WaldenWhite98.pdf&quot; rel=&quot;nofollow&quot;&gt;Walden and White (1998)&lt;/a&gt; to get the best fit filter that gets you from the reflectivity at the well to the seismic data along the well path. This filter is your mixed phase wavelet (at that one well location). If you do this at a couple wells and notice that the wavelet is relatively consistent, you can average the wavelets and apply the method of txpaulm to make your entire seismic data zero-phase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ok then, sorry for the long block of text...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, what if you don't have wells or don't want to use them for some reason?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Well, you can still estimate the phase spectrum of your wavelet directly from the seismic data by using the method &lt;a href=&quot;http://library.seg.org/doi/pdf/10.1190/1.1444109&quot; rel=&quot;nofollow&quot;&gt;Velis and Ulrych (1996)&lt;/a&gt; (and optimized by &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2478.2007.00597.x/abstract&quot; rel=&quot;nofollow&quot;&gt;Misra and Sacchi (2007)&lt;/a&gt;) based on 4th order cumulant matching between the seismic trace and an all-pass filter. Since this optimization problem is nonlinear, the method is computationally intensive as it requires a global optimization algorithm (Very Fast Simulated Annealing) and can be sensitive to noise. However, since this method does not require a well, it can be used to test the stationarity assumption about the seismic wavelet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mixed-phase wavelet extraction is a very popular field of research and you can probably find more information looking through the SEG and EAGE online libraries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Good luck!&#xA;-Antonio&lt;/p&gt;&#xA;" OwnerUserId="4636" LastEditorUserId="4636" LastEditDate="2016-02-28T00:05:09.820" LastActivityDate="2016-02-28T00:05:09.820" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7599" PostTypeId="1" AcceptedAnswerId="7603" CreationDate="2016-02-28T04:29:11.227" Score="8" ViewCount="964" Body="&lt;p&gt;I'm convinced there is a word for this. I was in the &lt;a href=&quot;http://www.albertaparks.ca/writing-on-stone/information-facilities/trails/hoodoo.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hoodoos at Writing on Stone&lt;/a&gt; this weekend and kept noticing what looked like reddish quartzite boulders laying around in the sand, or sometimes sticking partially out of the hoodoos. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When a non-sedimentary rock gets washed out into silt which later lithifies, what's it called? It's kind of like a conglomerate, except there's only a couple of really big rocks, which eventually fall out out the rock because all the sandstone around them eroded away. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LAi9s.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LAi9s.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="702" LastEditorDisplayName="user12525" LastEditDate="2019-08-27T11:18:49.223" LastActivityDate="2019-08-27T11:18:49.223" Title="What do you call boulders of non sedimentary rock that were lithified into sandstone?" Tags="|geology|rocks|sedimentology|geomorphology|terminology|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7600" PostTypeId="2" ParentId="7502" CreationDate="2016-02-28T07:10:24.813" Score="-11" Body="&lt;p&gt;The key part of this question is “Can CO2 with the ATMOSPHERE CONCENTRATION have a greenhouse effect?” &#xA;Assuming this is asking “At current levels, can changing levels of the greenhouse gas CO2 be shown to cause changes in Earth’s temperature?” (Yes, it is a greenhouse gas, … BUT).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer is NO. In fact the reverse can be shown, and that “experiment” is practised by astronomers every time they do IR measurements. There’s complete absorption of CO2’s IR wavebands when measured from surface-based instruments for decades. Everywhere, not just on this blog, there’s been much discussion that this IR is re-radiated by CO2 molecules, in all directions, which is true. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, none of this re-radiation can reach Earth because it encounters a greater concentration, ie higher absorption, in the lower levels. (Note, less than 50% can be directed back to Earth, and this % falls the greater the height of the re-radiation.)One can see this from surface-based instruments (mostly in telescopes) measuring zero transmission of CO2 IR spectra. This could not be zero if it did reach the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[There’s a longer – too long for here – argument presented in Chapter One (plus importantly, its Addendum) at my site “Planet Earth Climate Topics” @ pjcarson2015.wordpress.com.]&lt;/p&gt;&#xA;" OwnerUserId="5539" LastActivityDate="2016-02-28T07:10:24.813" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7601" PostTypeId="2" ParentId="7599" CreationDate="2016-02-28T07:47:38.090" Score="1" Body="&lt;p&gt;The word &lt;a href=&quot;https://en.wikipedia.org/wiki/Xenolith&quot; rel=&quot;nofollow&quot;&gt;xenolith&lt;/a&gt; (from ancient Greek, meaning stranger stone or foreign rock) is used to describe stones entrapped with an igneous matrix. However, as the reference states, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;a broad definition could include rock fragments which have become encased in sedimentary rock&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-02-28T07:47:38.090" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7603" PostTypeId="2" ParentId="7599" CreationDate="2016-02-29T03:30:57.347" Score="8" Body="&lt;p&gt;The technical term for a sedimentary rock that has a lithified fine-grained sediment with larger pieces of rocks suspended in it upon lithification is a &lt;strong&gt;conglomerate&lt;/strong&gt;. The fine-grained interstitial part is called the &lt;strong&gt;matrix&lt;/strong&gt;, and the large pieces suspended in it are called &lt;strong&gt;clasts&lt;/strong&gt;. Clasts can range from gravel- to boulder-size. These are technical terms used by sedimentologists.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is tempting to refer to these fragments as xenoliths but as that word has a very specific meaning in igneous petrology, it is best to avoid it to remove any confusion.&lt;/p&gt;&#xA;" OwnerUserId="496" LastActivityDate="2016-02-29T03:30:57.347" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7604" PostTypeId="2" ParentId="7467" CreationDate="2016-02-29T10:19:41.897" Score="5" Body="&lt;p&gt;&lt;strong&gt;Map elements and signatures&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Every signature used in the map (except of elevation contour lines) has to be explained in the legend. For example, the dashed line is not explained.&lt;/li&gt;&#xA;&lt;li&gt;Your map needs a scale bar or at least a numeric scale.&lt;/li&gt;&#xA;&lt;li&gt;Look for better signatures for the street/path and choose one for the river.&lt;/li&gt;&#xA;&lt;li&gt;To complete it, a topographic map is always better with a coordinate grid resp. coordinate information in labels at the map frame.&lt;/li&gt;&#xA;&lt;li&gt;You &lt;em&gt;could&lt;/em&gt; add a north arrow.&lt;/li&gt;&#xA;&lt;li&gt;To be completely correct, the map would need an information about the used projection and geodesic datum.&lt;/li&gt;&#xA;&lt;li&gt;If the map is created to be stand-alone later, don't forget to give it a title, date and information about author and cartographic survey or data source.&lt;/li&gt;&#xA;&lt;li&gt;The labels of the contour lines are normally orientated parallel to the lines. The direction is chosed so that you'd be able to read the labels naturally while walking uphill.&lt;/li&gt;&#xA;&lt;li&gt;Think about using an area signature for the swamp instead of symbols representing points.&lt;/li&gt;&#xA;&lt;li&gt;Optionally think about different area colours for either the water surface or the land surface; this makes it easier to differentiate between them.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&quot;Worldbuilding&quot; issues&lt;/strong&gt; &lt;em&gt;(if the map's content is fictional)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Guessing the scale with the help of the houses: The most southern houses and maybe even the northern ones are very, very close to the coast. Normally, you'll have a beach or cliffs or an anthropogenic shoreline leaving at least some space to the coast.&lt;/li&gt;&#xA;&lt;li&gt;Related to this, your elevation contour lines needs to be modified, once around the island's shore.&lt;/li&gt;&#xA;&lt;li&gt;Nearly all houses have the same size. &lt;/li&gt;&#xA;&lt;li&gt;Imagine the solar radiation: The houses in the north do all have the same orientation and stand, seen from south to north, at the same elevation. Therefore, they would experience much less solar radiation.&lt;/li&gt;&#xA;&lt;li&gt;Unless the marked houses aren't big community houses, there might be too many schools for the number of inhabitants.&lt;/li&gt;&#xA;&lt;li&gt;There is no transport infrastructure like a harbor or at least a landing stage for boats.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="4784" LastEditorUserId="4784" LastEditDate="2016-04-12T22:11:57.477" LastActivityDate="2016-04-12T22:11:57.477" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7606" PostTypeId="1" CreationDate="2016-03-01T08:51:24.033" Score="2" ViewCount="102" Body="&lt;p&gt;I'm trying to apply &lt;strong&gt;&lt;em&gt;sumigfd&lt;/em&gt;&lt;/strong&gt; on &lt;em&gt;simple.su&lt;/em&gt; data which is used in the John Stockwell &lt;a href=&quot;http://www.cwp.mines.edu/~john/GPGN461.561/ch1-14.pdf&quot; rel=&quot;nofollow&quot;&gt;course in geophysical image processing&lt;/a&gt; - in the Migration chapter on page 85. I have not had any success because the &lt;em&gt;vfile&lt;/em&gt; was not set up well. Even when I created a new &lt;em&gt;vfile&lt;/em&gt; the  problem persisits.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;surange &amp;lt; simple.su&#xA;&#xA;80 traces:&#xA;&#xA;tracl    1 80 (1 - 80)&#xA;cdp      1 80 (1 - 80)&#xA;trid     1&#xA;ns       501&#xA;dt       4000&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;After this information I created a &lt;em&gt;vfile&lt;/em&gt; using the instructions,&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt; makevel nx=80 nz=501 &amp;gt; cr&#xA; transp &amp;lt; cr n1=80 &amp;gt; ce&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="5551" LastEditorUserId="507" LastEditDate="2016-04-21T19:51:34.733" LastActivityDate="2016-04-21T19:51:34.733" Title="SeismicUnix - Finite Difference Migration" Tags="|geophysics|" AnswerCount="0" CommentCount="2" ClosedDate="2016-04-22T09:38:25.543" ContentLicense="CC BY-SA 3.0" />
  <row Id="7607" PostTypeId="1" AcceptedAnswerId="7608" CreationDate="2016-03-01T12:11:00.900" Score="2" ViewCount="11678" Body="&lt;p&gt;Why/how can rivers have sources in places high above the sea level?&lt;/p&gt;&#xA;" OwnerUserId="5016" LastEditorUserId="595" LastEditDate="2016-03-01T20:12:25.773" LastActivityDate="2021-10-13T21:56:16.333" Title="Why do rivers have 'wells' in mountains?" Tags="|hydrology|mountains|rivers|" AnswerCount="4" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7608" PostTypeId="2" ParentId="7607" CreationDate="2016-03-01T13:30:22.527" Score="8" Body="&lt;p&gt;The presence of water underground has nothing to do with sea level in mountainous country.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When rain fails on a mountain, or snow falls on a mountain and the snow eventually melts, the water from the rain or snow melt mostly travels downhill via rivers to the sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In getting to a river some of the water will fall on the ground. In places where the ground is covered by soil, water can travel through the soil via the pore spaces between the grains of soil. Similarly if porous rock, such as sandstone lies beneath the soil water can travel through the pores in the rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a layer of impervious rock lies under the porous rock or soil, the water cannot move downwards, due to gravity, any further. This can lead to water accumulating in the soil or porous rock and saturating the soil or rock. In such situations an &lt;a href=&quot;https://en.wikipedia.org/wiki/Aquifer&quot;&gt;aquifer&lt;/a&gt; can form. The top of the saturated zone in an aquifer is called a &lt;a href=&quot;https://en.wikipedia.org/wiki/Water_table&quot;&gt;water table&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ground beneath a river is saturated and the surface of the river shows the water table exposed to atmosphere. Thus in mountainous regions the ground beneath rivers will be saturated and capable of supporting a well developed from the bank of a river.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-03-01T13:30:22.527" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7609" PostTypeId="2" ParentId="7427" CreationDate="2016-03-01T14:56:32.857" Score="6" Body="&lt;p&gt;The previous answer is actually correct in stating that fish have very little to do with oil formation. Hydrocarbons of a volume that is able to accumulate a reservoir that is economic to produce requires significantly more source material. The greatest volume of material that is a viable source of hydrocarbons is zooplankton, those tiny little things taken collectively represent massive sources of material which can be converted to oil and gas. There has been a misrepresentation in the media that vertebrates are a source of oil and gas, but the volumes are just not balanced, the amount of oil available requires a massive source material, and the available area of the ocean, and short life cycle of zooplankton provide the proper volumetric balance. Phytoplankton are also have tremendous volume, but the material lacks the amount of oil source material to provide for significant contribution, more waxy than oily. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The previous answer indicates that the oil is in the sedimentary fans, and the source is from the rivers, this isn't true. The typical oil source rocks are organic black shales, and the oil and gas migrates after maturation to a reservoir where production can take place. There are a whole host of issues that can happen along the way that are either positive or negatives for accumulation of a viable reservoir. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Look up the oil production pathway to learn more than you ever wanted to know...the basics are, a source rock that spends the proper amount of time at the maturation temperature, then the primary migration from the source rock must occur, leading to a reservoir with characteristics that allow for production, porosity and permeability, a trap and seal. The previous answer is describing potential reservoirs not sources.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recent advances in hydraulic fracturing, which is an old process with new capabilities due to advances in drilling and production techniques allow for production from source rocks that have generated large volumes of gas that has not been able to migrate from the source into a reservoir where conventional production would have been used. Opening migration pathways and controlling the pressure in the source allows the gas to change phase and release from the source through the created pathways to the well for production.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;kwinkunks comment is right, vertebrates don't contribute to oil formation in any significant way.&lt;/p&gt;&#xA;" OwnerUserId="5097" LastActivityDate="2016-03-01T14:56:32.857" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7610" PostTypeId="2" ParentId="7607" CreationDate="2016-03-01T14:56:54.223" Score="5" Body="&lt;p&gt;What Fred said isn't wrong, but I think it doesn't answer the question very well so let me add some things:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First of all remember that water will always follow the gravitational force, so of course it's flowing downwards. Close to sea level the difference between the gravitational accelerations is almost zero between the spring and the sea.&#xA;Also most soils on or about sea level are well weathered and thus very thick, they can absorb a lot of water. So as Fred already said those &quot;lower rivers&quot; are mostly just the exposed ground water table, there isn't really that one source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now to the difference on mountains.&#xA;Mostly the higher you go the thinner the soil. Since there's almost no soil there's not much water that can be absorbed. Instead it accumulates in seas until their wall breaks and the water starts to flow downwards. It will then naturally carve it's way through the bedrock. Glaciers can also carve out huge amounts of rock and when melting create rivers that flow that way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the &quot;wells&quot;. I think you mean that one point where the water comes out of the mountain.&#xA;Remember mountains have in most cases higher precipitation and since not much water can be absorbed well it has to come down. &#xA;When the water hits the ground it seeps through cracks in the rock to the inner mountain. The chemical weathering will cause especially CaCO3 - rich rocks (carbonates) to dissolve. This will create caves (Karst) where the water then accumulates. The water &quot;flows&quot; within the mountain and will at some point create a little hole in the mountain from within. That's where the water then flows out and becomes a river. I think that hole would be your well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll add a picture for better understanding: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/CV5Gj.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="5274" LastEditorUserId="5274" LastEditDate="2016-03-01T21:05:13.680" LastActivityDate="2016-03-01T21:05:13.680" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7611" PostTypeId="2" ParentId="7607" CreationDate="2016-03-01T23:11:26.977" Score="3" Body="&lt;p&gt;Does your question go into the direction how the water gets 'onto the mountains'? Here is a meteorological-hydrological answer on this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course water, in its liquid form,is strongly determined by the gravitation. However when dissolved as water vapour, it is transported in the atmosphere (atmospheric water transport). Mountains do have an 'orographic effect' on the precipitation distribution in a landscape. This could, very very simplified, be described as follows: When air masses are horizontally moved, mountains represent barriers. The air has to rise onto along the mountains surface. In this upwards movement, the air expands. It gets thinner and can therefore contain less water vapour. In one point, it is oversaturated and begins to rain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the Encyclopaedia Britannica, there is a brief explanation with a good explaining figure: &lt;a href=&quot;http://www.britannica.com/science/orographic-precipitation&quot; rel=&quot;nofollow&quot;&gt;http://www.britannica.com/science/orographic-precipitation&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4784" LastActivityDate="2016-03-01T23:11:26.977" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7612" PostTypeId="1" AcceptedAnswerId="7640" CreationDate="2016-03-01T23:19:26.363" Score="4" ViewCount="718" Body="&lt;p&gt;What is radiation divergence, in the context of atmospheric physics? For example, the phrase is used in &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2009JD013074/abstract&quot;&gt;this paper&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2016-03-07T09:25:14.620" Title="What is radiation divergence?" Tags="|atmospheric-radiation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7613" PostTypeId="1" AcceptedAnswerId="7614" CreationDate="2016-03-01T23:44:45.450" Score="2" ViewCount="1315" Body="&lt;p&gt;How can I calculate the final concentration of two ions in a river after the confluence of two rivers?&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;River 1 flows at $\small\sf{7000\ L/s}$, contains $\small\sf{500\ mg/L\ Mg,\ 1.1\&#xA;   g/L\ Ca}$&lt;/li&gt;&#xA;&lt;li&gt;River 2 flows at $\small\sf{11\ m^3/s}$, contains $\small\sf{0.34\ g/L\ Mg,\ 200\&#xA;   mg/L\ Ca}$&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;How do I find Mg and Ca concentrations in River 3, after the joining of Rivers 1 and 2?&lt;/p&gt;&#xA;" OwnerUserId="5560" LastEditorUserId="2470" LastEditDate="2016-03-02T01:45:51.690" LastActivityDate="2016-03-02T02:16:27.723" Title="Mixing equation for confluence of two rivers" Tags="|geochemistry|biogeochemistry|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7614" PostTypeId="2" ParentId="7613" CreationDate="2016-03-02T00:58:45.593" Score="3" Body="&lt;p&gt;You have to use mass weighted averaging to calculate the final concentrations of elements. The equation for your situation would be:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\sf\bar{q}\ =\ \dfrac{m_1.q_1\ +\ m_2.q_2}{m_1\ +\ m_2}\ =\ \dfrac{\rho_1.v_1.q_1\ +\ \rho_2.v_2.q_2}{\rho_1.v_1\ +\ \rho_2.v_2}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$\small\sf m$ is the mass flow rate&lt;/li&gt;&#xA;&lt;li&gt;$\small\sf v$ is the volume flow rate&lt;/li&gt;&#xA;&lt;li&gt;$\small\rho$ is the density of water&lt;/li&gt;&#xA;&lt;li&gt;$\small\sf q$ is the quantity/concentration of the element&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Every second, $\small\sf{7000\ L}$ of water flows from River 1 into River 3. Similarly, $\small\sf{11\ m^3}$ of water flows from River 2 into River 3. The combined inflow into River 3 is $\small\sf{18\ m^3}$ every second.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming the density of water in both inflowing rivers is the same, volume of water can be used instead of mass; if not then the density of water for each river needs to be used.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming the water density of both rivers is the same, convert all to units SI units and the average concentration of Mg in River 3 is,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\sf{\dfrac{7(0.5) + 11(0.34)}{(7 + 11)}}$ = $\sf{0.402\ g/L\ Mg}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll let you do the calculation for Ca.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2016-03-02T02:16:27.723" LastActivityDate="2016-03-02T02:16:27.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7615" PostTypeId="2" ParentId="212" CreationDate="2016-03-02T13:54:37.550" Score="1" Body="&lt;p&gt;Mass at 21.9.1998 for Height 140 km -1000 km was $6.16\cdot10^{10} \mathrm{kg}$.&lt;br&gt;&#xA;Avg. Temperature; $725 \mathrm{K}$  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Roughly the mass is divided as follows;&lt;br&gt;&#xA;$\mathrm{O}$, $\mathrm{O}_2$; $252 \cdot10^9 \mathrm{kg}$, “16” Molecule amount $N = 9.5\cdot10^{35}$,&lt;br&gt;&#xA;Heat capacity; $920 \mathrm{J}/(\mathrm{kg} \mathrm{K})$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\mathrm{N}$, $\mathrm{N}_2$; $364 \cdot10^9 \mathrm{kg}$; “14” Molecule amount $N = 1.56\cdot10^{36}$,&lt;br&gt;&#xA;Heat capacity; $1040 \mathrm{J}/(\mathrm{kg}\mathrm{K})$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\mathrm{He}$; $35.2\cdot10^6 \mathrm{kg}$, “4” Molecule amount $N = 5.3\cdot10^{33}$,&lt;br&gt;&#xA; Heat capacity; $5193 \mathrm{J}/(\mathrm{kg} \mathrm{K})$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\mathrm{H}$; $1.34\cdot10^6 \mathrm{kg}$, “1” Molecule amount $N = 0.8\cdot10^{33}$,&lt;br&gt;&#xA;Heat capacity; $14304 \mathrm{J}/(\mathrm{kg}\mathrm{K})$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Total Heat capacity; $61.2\cdot10^{12} \mathrm{J}/\mathrm{K}$ &#xA;Quelle; &lt;a href=&quot;https://www.researchgate.net/publication/294535112_QED_explanation_for_Gravity_and_Radioactivity_Theory_of_Everything&quot; rel=&quot;nofollow&quot;&gt;My own work&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From here you can calculate $725 \mathrm{K} \cdot 61.2 \cdot10^{12} \mathrm{J}/\mathrm{K} =44.4 \cdot10^{15} \mathrm{J}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please note that most of the heat is at the lower atmosphere plain because &gt;99% of the mass is there. &lt;/p&gt;&#xA;" OwnerUserId="3098" LastEditorUserId="681" LastEditDate="2016-03-04T11:07:33.503" LastActivityDate="2016-03-04T11:07:33.503" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7616" PostTypeId="2" ParentId="5135" CreationDate="2016-03-02T15:09:53.647" Score="2" Body="&lt;p&gt;In addition to Gordons approach it might be possible to differentiate between impact and volcanic craters by comparing the characteristics of the ejecta [1]. The apparent thermal inertia (defined for example in [2]) seems to be higher around volcanic craters [3]. Unfortunately the linked papers about the method are conference abstracts about ongoing research and I did not find a paper where they try to apply the method to remote sensing data from mars.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1] Peet, V. M., M. S. Ramsey, and D. A. Crown. &quot;Comparison of Terrestrial Morphology, Ejecta, and Sediment Transport of Small Craters: Volcanic and Impact Analogs to Mars.&quot; 36th Annual Lunar and Planetary Science Conference. Vol. 36. 2005.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[2] Putzig, Nathaniel E., and Michael T. Mellon. &quot;Apparent thermal inertia and the surface heterogeneity of Mars.&quot; Icarus 191.1 (2007): 68-94.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[3] Peet, V. M., M. S. Ramsey, and D. A. Crown. &quot;Remote Sensing Analyses of Small Terrestrial Volcanic and Impact Craters: A Mars Analog for Formation, Morphology, and Erosional Processes.&quot; Lunar and Planetary Science Conference. Vol. 38. 2007.&lt;/p&gt;&#xA;" OwnerUserId="2861" LastActivityDate="2016-03-02T15:09:53.647" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7617" PostTypeId="1" AcceptedAnswerId="12495" CreationDate="2016-03-02T15:45:58.757" Score="11" ViewCount="504" Body="&lt;p&gt;In Paris, actually, it is snowing smoothly and the temperature, according to many sources, is around $\small\sf{9^o}$ Celsius. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I had always the feeling that snow is possible when temperature approaches $\small\sf0^o$ or below $\small\sf0^o$ Celsius (apparently, it is a huge prejudice)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How is that possible?&lt;/p&gt;&#xA;" OwnerUserId="2827" LastEditorUserId="2470" LastEditDate="2016-03-02T15:51:54.073" LastActivityDate="2017-10-18T22:04:12.877" Title="Snowing when the actual temperature is around $\small\sf9^o$ Celsius" Tags="|temperature|snow|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7618" PostTypeId="1" CreationDate="2016-03-03T07:54:58.260" Score="2" ViewCount="345" Body="&lt;p&gt;In literature some times to account for semi-pervious sediments at bottom of stream, streambed leakance also called retardation coefficient ($L$) is used. This is equal to the ratio of conductivity of aquifer to streambed multiplied by thickness of streambed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On other hand, another term seems to describe the effect of same less permeable sediments on bottom of river named as &quot;&lt;em&gt;Riverbed conductance&lt;/em&gt;&quot; ($L2/T$) used in MODFLOW. This is equal to $K \cdot A / L$, where $K$ is conductivity of riverbed, $A$ is area of cell and $L$ is length. Is this the only difference between these two terms? &lt;/p&gt;&#xA;" OwnerUserId="5557" LastEditorUserId="5594" LastEditDate="2017-12-13T10:14:48.047" LastActivityDate="2017-12-13T10:14:48.047" Title="What is difference between Riverbed conductance term and streambed leakance/retardation coefficient?" Tags="|hydrology|rivers|numerical-modelling|groundwater|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7620" PostTypeId="2" ParentId="7617" CreationDate="2016-03-03T15:25:15.533" Score="7" Body="&lt;p&gt;As mentioned in the comments, the air temperature is the deciding factor. In the Troposphere, until ca. 15 km, the temperature decreases by about 6 °C per km altitude (more info on the lapse rate &lt;a href=&quot;http://pds-atmospheres.nmsu.edu/education_and_outreach/encyclopedia/adiabatic_lapse_rate.htm&quot;&gt;here&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an additional factor, the air temperature on ground levels is generally higher in urban environments, like Paris. Therefore, the natural outer conurbation area could provide lower temperatures, while it is warmer in the city due to the anthopogenic heating (cars/engines, house heating, ...).&lt;/p&gt;&#xA;" OwnerUserId="4784" LastEditorUserId="4784" LastEditDate="2016-03-03T15:35:44.987" LastActivityDate="2016-03-03T15:35:44.987" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7622" PostTypeId="2" ParentId="7599" CreationDate="2016-03-03T17:31:10.103" Score="3" Body="&lt;p&gt;Nodules, as in chert nodules are common in limestone, but not confined to any particular sedimentary rock.&lt;/p&gt;&#xA;" OwnerUserId="5570" LastActivityDate="2016-03-03T17:31:10.103" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7625" PostTypeId="2" ParentId="7467" CreationDate="2016-03-04T03:32:56.770" Score="2" Body="&lt;p&gt;Some hints to get you thinking.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Remember contours are lines joining points of the same elevation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's say the island is in the ocean - what is the elevation of the shore-line around the island? If it is in a lake above sea level, would the elevation of the shore be different in different places?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So could a contour line run into the shore the way you have drawn them?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You have closed the contours around the hills - good. But what happens in low lying areas like the swamp? Wouldn't the land rise up on either side of the swamp? Would that mean that the contours mostly go around it? The contours might not close completely around the low-land the way they would around a hill-top unless you have a closed basin but they will spread out at flat areas. Think about working up from the shore as well as working down from the hills. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You have a River labeled but not drawn in. Maybe draw in where you think the river flows (hint rivers usually run in valleys and water flows downhill). This is kind of hard to visualise, but if you have a river valley running down a slope, the contour line will 'deflect' upstream where it crosses the river. Similarly a contour line will deflect away from the peak of a hill when it crosses a ridgeline. Try looking at a contour map of an area you know and see how it works.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2016-03-04T03:32:56.770" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7627" PostTypeId="1" AcceptedAnswerId="7628" CreationDate="2016-03-05T14:57:16.930" Score="15" ViewCount="1194" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Nwo2e.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Nwo2e.jpg&quot; alt=&quot;co2&quot; /&gt;&lt;/a&gt;&#xA;(Description from climate.nasa.gov: This graph, based on the comparison of atmospheric samples contained in ice cores and more recent direct measurements, provides evidence that atmospheric &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; has increased since the Industrial Revolution. (Credit: Vostok ice core data/J.R. Petit et al.; NOAA Mauna Loa CO2 record.))&lt;/p&gt;&#xA;&lt;p&gt;I'm not sure where and why has all &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; gone every 100.000 years and out of where has &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; come?&lt;/p&gt;&#xA;&lt;p&gt;But if &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; came from burning trees or volcanoes and disappeared because plants adapted then I have this question:&lt;/p&gt;&#xA;&lt;p&gt;Plants somehow tolerated these 100.000 year &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; changes over time which is very evolutionary small time. So perhaps adaptation was just about changing plants' composition percentages which is very flexible. When some rare &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; eating trees came to be more frequent. But if that's true why can't plants change their composition again to adjust for human &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt;-emissions pace?&lt;/p&gt;&#xA;" OwnerUserId="5577" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2021-05-30T14:47:17.403" Title="How did plants adapt to $\small\sf{CO_2}$ levels past 400k years? Why won't they do it again?" Tags="|climate-change|carbon-cycle|" AnswerCount="5" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="7628" PostTypeId="2" ParentId="7627" CreationDate="2016-03-05T21:06:12.023" Score="16" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;I'm not sure where and why has all CO2 gone every 100.000 years and out of where has CO2 come?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The amount of CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere for the last 400000 years is very strongly correlated with temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/ENRCh.png&quot; alt=&quot;&quot; title=&quot;Graph that depicts atmospheric CO&amp;#x2082; levels and temperature change from the present, both as functions of time. The two curves are very similar to one another.&quot;&gt;&lt;br&gt;&#xA;&lt;sub&gt;Temperature change (blue) and carbon dioxide change (red) observed in ice core records.&lt;br&gt;&#xA;Image source: &lt;a href=&quot;https://www.ncdc.noaa.gov/paleo/globalwarming/temperature-change.html&quot; rel=&quot;noreferrer&quot;&gt;https://www.ncdc.noaa.gov/paleo/globalwarming/temperature-change.html&lt;/a&gt;.&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;Glaciations currently occur at roughly one hundred thousand year intervals, driven primarily by &lt;a href=&quot;http://www.eoearth.org/view/article/154612/&quot; rel=&quot;noreferrer&quot;&gt;Milankovitch cycles&lt;/a&gt;. So what causes the strong correlation between temperature and carbon dioxide levels? The primary reason for this marked correlation is that carbon dioxide dissolves in cold water much more readily than it does in warm water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a glacial period starts, the oceans gradually get colder worldwide as ice gradually spreads over the Northern Hemisphere. This enables oceans to absorb carbon dioxide from the atmosphere. Atmospheric CO&lt;sub&gt;2&lt;/sub&gt; drop as a glaciation proceeds. The plot shows that both temperature and CO&lt;sub&gt;2&lt;/sub&gt; levels drop rather slowly over the course of a glaciation, and then both rise rather quickly as the glaciation ends.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One reason for this is atmospheric carbon dioxide levels. The Milankovitch cycles triggers the end of a glaciation. The warming oceans cannot hold as much carbon dioxide as they could during the depths of the glaciation and release carbon dioxide to the atmosphere. This exacerbates the warming, releasing even more carbon dioxide into the atmosphere. This makes the escape from a glaciation much steeper than the entry into one (&lt;a href=&quot;http://www.nature.com/nature/journal/v484/n7392/full/nature10915.html&quot; rel=&quot;noreferrer&quot;&gt;Shakun 2012&lt;/a&gt;). A nice graph from the cited paper:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/5CFHn.jpg&quot; alt=&quot;&quot; title=&quot;Two graphs, the first of which plots global temperature, Antarctic temperature, and CO&amp;#x2082; level, each as functions of time, from 22000 years ago to 7 thousand years ago; the second shows that CO&amp;#x2082; levels generally lag Southern Hemisphere temperatures but leads Northern Hemisphere temperatures and global temperatures in simulated results.&quot;&gt;&lt;br&gt;&#xA;&lt;sub&gt;Upper plot: CO&amp;#x2082; concentration (yellow circles), global temperature (blue), and Antarctic temperature (red).&lt;br&gt;&#xA;Lower plot: Simulation results that show that Southern Hemisphere temperatures tends to lead but global temperatures tend to lag CO&amp;#x2082; levels.&lt;br&gt;&#xA;Image source: &lt;a href=&quot;http://www.nature.com/nature/journal/v484/n7392/fig_tab/nature10915_F2.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.nature.com/nature/journal/v484/n7392/fig_tab/nature10915_F2.html&lt;/a&gt;.&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;But if CO2 came from burning trees or volcanoes and disappeared because plants adapted then I have this question:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Plants somehow tolerated these 100.000 year CO2 changes over time which is very evolutionary small time. So perhaps adaptation was just about changing plants' composition percentages which is very flexible. When some rare CO2 eating trees came to be more frequent. But if that's true why can't plants change their composition again to adjust for human CO2-emissions pace?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Your question is a bit moot since the increases in CO&lt;sub&gt;2&lt;/sub&gt; did not come from burning trees or volcanoes and did not disappear because plants adapted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/nature/journal/v484/n7392/full/nature10915.html&quot; rel=&quot;noreferrer&quot;&gt;Jeremy Shakun, et al., &quot;Global warming preceded by increasing carbon dioxide concentrations during the last deglaciation,&quot; &lt;em&gt;Nature&lt;/em&gt; 484.7392 (2012): 49-54.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2019-01-01T17:40:01.150" LastActivityDate="2019-01-01T17:40:01.150" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="7629" PostTypeId="1" AcceptedAnswerId="7641" CreationDate="2016-03-06T10:29:15.720" Score="5" ViewCount="406" Body="&lt;p&gt;As rivers flow into the sea, rivers contain a high concentration of calcium and carbonates, and a low concentration of sodium and chlorine, and for marine water it is vice versa. How come?&lt;/p&gt;&#xA;" OwnerUserId="5578" LastEditorUserId="502" LastEditDate="2016-03-08T21:49:56.177" LastActivityDate="2016-03-08T21:50:29.977" Title="Marine and freshwater geochemistry" Tags="|geochemistry|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7631" PostTypeId="1" CreationDate="2016-03-07T04:04:41.067" Score="5" ViewCount="206" Body="&lt;p&gt;In this &lt;a href=&quot;https://www.nature.nps.gov/air/aqbasics/ozoneEffects.cfm&quot; rel=&quot;noreferrer&quot;&gt;National Park Service article&lt;/a&gt;, the effects of ozone on trees is discussed:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Ozone enters plants through leaf openings called stomata and oxidizes plant tissue, causing changes in biochemical and physiological processes. Both visible foliar injury (e.g., stipple and chlorosis) and growth effects (e.g., premature leaf loss, reduced photosynthesis, and reduced leaf, root, and total dry weights) can occur in sensitive plant species. Many other factors can magnify the extent of ozone injury such as soil moisture, presence of other air pollutants, insects or diseases, and other environmental stresses.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I assume that ozone can adversely affect many types of plants, including agricultural crops.  Which crops are especially sensitive to atmospheric ozone?&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-03-07T11:01:09.027" Title="Which crops are especially sensitive to atmospheric ozone?" Tags="|ozone|agriculture|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7632" PostTypeId="1" AcceptedAnswerId="7639" CreationDate="2016-03-07T06:08:51.377" Score="6" ViewCount="1525" Body="&lt;p&gt;Ok, it looks like a very simple question but I still have some point want to clarify...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most images explain volcanos contain some orange stuffs as magma below volcanoes as magma chamber, but the problem is, what is the primary source of the magma? I have 2 assumptions but don't know which is correct:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Magma is directly supplied from magma below crust, in subduction zone the crust rubs and some cracks formed, magma rushes out from mantle and then to the surface of Earth via cracks.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The magma is formed by molten crust cause by rubbing and then heating, then it rushes out via cracks. In other words, the magma is originally a part of crust and it just melt again through rubbing, which is not related to the magma below crust.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Which is correct?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="725" LastEditDate="2016-03-07T08:52:20.333" LastActivityDate="2016-03-07T08:52:20.333" Title="What is the source of lava of volcano? From magma below crust? Or from molten crust by rubbing?" Tags="|geology|volcanology|petrology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7633" PostTypeId="2" ParentId="7627" CreationDate="2016-03-07T06:30:21.987" Score="-12" Body="&lt;p&gt;Temperature and a alkaline soil with ph level over 7,Salinity and the suns radiation is a guarantee and the dew collected every morning is all most plant life needs to survive. Co2 is not even a factor. The Earth has lost all its Co2 plenty of times and the plants thrive along with the microbes to start life over. &lt;/p&gt;&#xA;" OwnerUserId="4617" LastActivityDate="2016-03-07T06:30:21.987" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7634" PostTypeId="2" ParentId="7631" CreationDate="2016-03-07T06:48:15.503" Score="-3" Body="&lt;p&gt;All crops will not produce correctly if the soil is too lose and wet, fungus and rot will take place on the fruit and the root without a 8 hour dry cycle time. The only crops that will survive in the environment you are concerned about are &lt;strong&gt;root vegetables&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Taproot (some types may incorporate substantial hypocotyl tissue)&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Arracacia xanthorrhiza (arracacha)&#xA;Abelmoschus moschatus (bush carrot)&#xA;Beta vulgaris (beet and mangelwurzel)&#xA;Brassica spp. (rutabaga and turnip)&#xA;Bunium persicum (black cumin)&#xA;Burdock (Arctium, family Asteraceae)&#xA;Carrot (Daucus carota subsp. sativus)&#xA;Celeriac - (Apium graveolens rapaceum)&#xA;Daikon - the large East Asian white radish (Raphanus sativus var. longipinnatus)&#xA;Dandelion - (Taraxacum) spp.&#xA;Lepidium meyenii (maca)&#xA;Microseris scapigera (yam daisy)&#xA;Pachyrhizus spp. (jicama and ahipa)&#xA;Parsnip (Pastinaca sativa)&#xA;Petroselinum spp. (parsley root)&#xA;Radish - (Raphanus sativus)&#xA;Scorzonera hispanica (black salsify)&#xA;Sium sisarum (skirret)&#xA;Tragopogon spp. (salsify)&#xA;Vigna lanceolata (bush potato)&#xA;Tuberous root&#xA;Amorphophallus galbra (Yellow lily yam)&#xA;Conopodium majus (pignut or earthnut)&#xA;Dioscorea polystachya (nagaimo, Chinese yam, Korean yam, mountain yam)&#xA;Hornstedtia scottiana (Native ginger)&#xA;Ipomoea batatas (sweet potato)&#xA;Ipomoea costata (desert yam)&#xA;Manihot esculenta (cassava or yuca or manioc)&#xA;Mirabilis extensa (mauka or chago)&#xA;Psoralea esculenta (breadroot, tipsin, or prairie turnip)&#xA;Smallanthus sonchifolius (yacón)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Rhizome&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Curcuma longa (turmeric)&#xA;Panax ginseng (ginseng)&#xA;Arthropodium spp. (rengarenga, vanilla lily, and others)&#xA;Canna spp. (canna)&#xA;Cordyline fruticosa (ti)&#xA;Maranta arundinacea (arrowroot)&#xA;Nelumbo nucifera (lotus root)&#xA;Typha spp. (cattail or bulrush)&#xA;Zingiber officinale (ginger, galangal)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Tuber&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apios americana (hog potato or groundnut)&#xA;Cyperus esculentus (tigernut or chufa)&#xA;Dioscorea spp. (yams, ube)&#xA;Helianthus tuberosus (Jerusalem artichoke or sunchoke)&#xA;Hemerocallis spp. (daylily)&#xA;Lathyrus tuberosus (earthnut pea)&#xA;Oxalis tuberosa (oca or New Zealand yam)&#xA;Plectranthus edulis and P. esculentus (kembili, dazo, and others)&#xA;Solanum tuberosum (potato)&#xA;Stachys affinis (Chinese artichoke or crosne)&#xA;Tropaeolum tuberosum (mashua or añu)&#xA;Ullucus tuberosus (ulluco)&lt;/p&gt;&#xA;" OwnerUserId="4617" LastActivityDate="2016-03-07T06:48:15.503" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7635" PostTypeId="2" ParentId="7632" CreationDate="2016-03-07T07:00:18.770" Score="-5" Body="&lt;p&gt;Neither, Eruptions of extreme magnitude occur when the magnetic field of a planet is slowly depleting due to the upcoming reverse in polarity. The core of the planet will start to liquefy from the high levels of solar radiation because the magnetic field is weakening and not able to block the radiation daily.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So basically its like overcooking a soup at high temperatures, the soup will eventually overflow and spill out.&lt;/p&gt;&#xA;" OwnerUserId="4617" LastActivityDate="2016-03-07T07:00:18.770" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7636" PostTypeId="2" ParentId="7629" CreationDate="2016-03-07T07:35:28.510" Score="-1" Body="&lt;p&gt;Rivers from land that flow into the ocean supply the oceans salts and chlorine from billions of years​ of weathering, minerals break down and the salts accumulate in the ocean. The oceans don't flow through land. The river water will never taste salty because the salts are released in small amounts over billions of years.&lt;/p&gt;&#xA;" OwnerUserId="4617" LastEditorUserId="502" LastEditDate="2016-03-08T21:50:29.977" LastActivityDate="2016-03-08T21:50:29.977" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7639" PostTypeId="2" ParentId="7632" CreationDate="2016-03-07T08:51:28.783" Score="4" Body="&lt;p&gt;Both are correct to some degree.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basalts are usually the result of direct mantle melting, below the crust. This is the case in the famous volcanos of Hawaii and this is also the case in the most common type of volcanism on Earth: the mid-ocean ridges (albeit hidden below several kilometres of sea water).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most other eruptive rocks (rhyolite, andesite, etc) are usually the result of either melting of the crust, or interaction of mantle melts (basalts) with crustal rocks. A very large portion of these rocks erupt above subduction zones (most obvious example being the &lt;a href=&quot;http://education.nationalgeographic.org/encyclopedia/ring-fire/&quot; rel=&quot;nofollow&quot;&gt;Ring of Fire&lt;/a&gt;). The reason is that wet subducting oceanic lithospheres get heated and lose their water. We usually think of water as something that puts out fires, but in the deep Earth it actually lowers the melting point of rocks. This causes melting in the crust, and eventually erupts as volcanoes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a very simplified overview of the subject, and it's a very active area of scientific research with sometimes opposing opinions. But the basic story is somewhat established: some volcanoes (mostly basalts) are products of mantle melting, while others (mostly other stuff) are products of crustal melting.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-03-07T08:51:28.783" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7640" PostTypeId="2" ParentId="7612" CreationDate="2016-03-07T09:25:14.620" Score="3" Body="&lt;p&gt;The way I understand it, the net longwave radiation $L^\star:=L^\downarrow-L^\uparrow$ (maybe with different sign), i.e. the difference between downwelling and upwelling radiation, can be viewed as a vector field (with vanishing horizontal components under the assumption of homogeneous horizontal radiation distribution). This vector field has a divergence $\nabla\cdot L^\star=\frac{\partial L^\star}{\partial z}$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This term occurs in equation (1) of the paper you referenced as part of the heating rate. Since non-vanishing divergence is in a vector field is associated with the field having a source or sink, this corresponds to heating/cooling of the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="681" LastActivityDate="2016-03-07T09:25:14.620" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7641" PostTypeId="2" ParentId="7629" CreationDate="2016-03-07T10:13:45.180" Score="6" Body="&lt;p&gt;The oceans are not saturated in sodium or chlorine. In fact, the chemical makeup of the oceans has remained fairly constant for hundreds of millions of years. Yet rivers and other sources continually bring sodium, chlorine, and other dissolved elements and compounds to the oceans. This means some processes must exist that remove constituent elements at more or less the same rate that the world's rivers and other sources supply these constituents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is true that the Earth's rivers bring substantially more calcium and carbonate ions to the oceans than they bring sodium and chlorine ions. Dissolved carbon dioxide from the atmosphere provides another source of carbonate ions. Yet the oceans are indeed substantially depleted of calcium and carbonate compared to the supply from rivers. So why is this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The oceans are substantially saltier than are the rivers that supply the oceans. This is primarily a result of evaporation. Even with that, sodium and chlorine are but a fraction of their saturation levels in the world's oceans. This is not the case for calcium and carbonate. Carbonates in general have a low saturation level, and amongst common cations, calcium carbonate has a very low saturation level. Calcium carbonate is typically at or near the saturation level in the oceans, and oftentimes above it, particularly near the surface. This makes it very easy for calcium carbonate to come out of solution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because calcium and carbonate are at or above the saturation level, just about anything can cause calcium carbonate to form. The key &quot;just about anything&quot; process that causes calcium and carbonate to come out of solution is life.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This means that calcium and carbonate have a rather low residence time in the oceans. The processes that remove sodium and chlorine are much, much slower. The slowness by which sodium and chlorine are removed versus the rapidity by which calcium and carbonate are removed are why the oceans are &quot;upside down&quot; compared to rivers with regard to calcium, carbonate, sodium, and chlorine.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2016-03-07T17:51:11.717" LastActivityDate="2016-03-07T17:51:11.717" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7643" PostTypeId="2" ParentId="7631" CreationDate="2016-03-07T11:01:09.027" Score="6" Body="&lt;p&gt;I could find a relatively recent review by &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S1352231006011356&quot;&gt;Mills et al. (2007)&lt;/a&gt; that lists sensitivity to ozone for several crops. Among the most sensitive were (table 1)&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Watermelons (albeit with very few data points used)&lt;/li&gt;&#xA;&lt;li&gt;Pulses&lt;/li&gt;&#xA;&lt;li&gt;Cotton&lt;/li&gt;&#xA;&lt;li&gt;Wheat&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;While the most resistant crops were&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Barley&lt;/li&gt;&#xA;&lt;li&gt;Fruits (Plums and Strawberries)&lt;/li&gt;&#xA;&lt;li&gt;Broccoli&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The measure for ozone used in this review is AOT40, which accounts for accumulated ozone levels over 40ppbV within the time from 8AM to 8PM.&lt;/p&gt;&#xA;" OwnerUserId="681" LastActivityDate="2016-03-07T11:01:09.027" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7644" PostTypeId="1" CreationDate="2016-03-07T14:43:50.510" Score="9" ViewCount="39204" Body="&lt;p&gt;When I was in school, I was taught that we need oxygen to breathe, but it actually constitutes only a small fraction of the atmospheric composition, and that nitrogen constituted the largest fraction of the atmosphere's composition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.co.uk/?gfe_rd=cr&amp;amp;ei=3pXdVtz-NYvS8Aelgb_oDg&amp;amp;gws_rd=ssl#q=most+abundant+element+on+earth&quot; rel=&quot;noreferrer&quot;&gt;This quick Google search&lt;/a&gt; mentions oxygen as the most abundant element.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can this be reconciled?&lt;/p&gt;&#xA;" OwnerUserId="5583" LastEditorUserId="725" LastEditDate="2016-03-08T04:22:45.503" LastActivityDate="2018-10-19T21:22:37.540" Title="Is oxygen the most abundant element on Earth?" Tags="|atmosphere|geochemistry|nitrogen|oxygen|" AnswerCount="2" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="7645" PostTypeId="2" ParentId="7644" CreationDate="2016-03-07T16:01:38.200" Score="12" Body="&lt;p&gt;Both of them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The composition of the atmosphere, crust, mantle, core and bulk earth are all notably different.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The atmosphere is composed of ~78% nitrogen and ~21% oxygen, with small amounts of other gases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cGwUy.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cGwUy.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The bulk composition of the earth by weight is mostly, iron, oxygen, silicon and magnesium, in that order, with all the other elements making up only about 5% of the earth's weight. Most of the earth's iron is in the core, which is about 85% iron. The rest of the earth is dominated by oxygen and silicon, primarily in the form of silicate minerals, which consist of $\ce{SiO4^{4-}}$ tetrahedra linked in different ways and with different cations filling in the gaps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ajURi.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ajURi.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2016-03-07T16:01:38.200" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7646" PostTypeId="1" CreationDate="2016-03-07T16:21:02.307" Score="1" ViewCount="356" Body="&lt;p&gt;The major mountain chains of Earth are found near:&#xA;Convergent (subduction) and convergent (collisional) boundaries or transform boundaries?&lt;a href=&quot;https://i.stack.imgur.com/HmbH1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HmbH1.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;it should be both subduction and collisional right?&lt;/p&gt;&#xA;" OwnerUserId="5585" LastEditorUserId="5585" LastEditDate="2016-03-07T16:47:05.810" LastActivityDate="2016-03-07T16:47:05.810" Title="Largest mountain range" Tags="|mountains|orogeny|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7647" PostTypeId="1" CreationDate="2016-03-07T17:07:10.397" Score="3" ViewCount="146" Body="&lt;p&gt;What probability distribution do wind speed measurements typically follow?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have seen a Weibull distribution used, but the page was a bit lacking on background information so I would appreciate confirmation and a reference, if possible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If it is a Weibull, are there typical parameters that are used, or can these vary?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks.&lt;/p&gt;&#xA;" OwnerUserId="1071" LastActivityDate="2016-03-08T19:21:03.367" Title="How are wind speeds typically distributed?" Tags="|meteorology|wind|statistics|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7648" PostTypeId="1" AcceptedAnswerId="7650" CreationDate="2016-03-07T17:29:17.067" Score="4" ViewCount="557" Body="&lt;p&gt;While attending a lecture about monsoon, our professor mentioned about pre-monsoon showers. However, he never bothered to explain it. So, what is a pre-monsoon shower and what are its distinguishing features from monsoon showers?&lt;/p&gt;&#xA;" OwnerUserId="5587" LastEditorUserId="5587" LastEditDate="2016-03-07T17:44:13.713" LastActivityDate="2016-04-07T00:08:04.873" Title="What is a pre-monsoon shower? Is there any distinguishing feature between monsoon and pre-monsoon showers?" Tags="|meteorology|monsoon|rain|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7649" PostTypeId="2" ParentId="7644" CreationDate="2016-03-07T19:06:49.953" Score="2" Body="&lt;p&gt;&quot;How can this be reconciled?&quot;  In two words: silicon dioxide :-)  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, that's simplistic, but reflects the fact that virtually all the oxygen occurs in chemical combinations with other elements, not as free oxygen.   The same is true for other elements in the crust &amp;amp; mantle.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2016-03-07T19:06:49.953" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="7650" PostTypeId="2" ParentId="7648" CreationDate="2016-03-07T23:54:29.557" Score="2" Body="&lt;p&gt;Mango showers, or ‘mango rains’, is a colloquial term to describe the occurrence of pre-monsoon rainfall! Monsoon is prevailing wind due to seasonal changes in atmospheric circulation and precipitation associated with the asymmetric heating of land and sea. Usually, the term monsoon is used to refer to the rainy phase of a seasonally changing pattern. They are notable across much of South and Southeast Asia, including India, and Cambodia. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Monsoon&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Monsoon&lt;/a&gt; here is a helpful resource I used!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;:)&lt;/p&gt;&#xA;" OwnerUserId="5589" LastActivityDate="2016-03-07T23:54:29.557" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7651" PostTypeId="1" CreationDate="2016-03-08T01:50:30.380" Score="6" ViewCount="62" Body="&lt;p&gt;In the tropics, say the Caribbean, I have read that there is very often a lot of nighttime and morning fog. I have read that the crucial factors are&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The ocean temperature&lt;/li&gt;&#xA;&lt;li&gt;Cool nighttime air temperatures&lt;/li&gt;&#xA;&lt;li&gt;The movement of air from areas above land to areas above the sea&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Assuming this is more or less correct, I am wondering if there is any way to estimate the effect of a local rise in sea temperature, say by 1&amp;deg;C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My guess is that you'll get more fog lasting later, but I don't really know what I'm talking about.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: if I have incorrectly described the issues at stake, I would be pleased to be corrected.&lt;/p&gt;&#xA;" OwnerUserId="5590" LastEditorUserId="111" LastEditDate="2016-07-05T02:42:31.497" LastActivityDate="2016-07-05T02:42:31.497" Title="Estimating fog incidence based on ocean temperature" Tags="|meteorology|ocean|temperature|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="7652" PostTypeId="2" ParentId="7647" CreationDate="2016-03-08T13:33:23.140" Score="6" Body="&lt;p&gt;Yes, the most commonly used distribution for wind speed is the Weibull - at least when it comes to predicting wind speeds at prospective wind farm locations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, the parameters vary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See, for example, the book &lt;a href=&quot;http://www.wind-energy-the-facts.org/the-annual-variability-of-wind-speed.html&quot; rel=&quot;noreferrer&quot;&gt;&quot;Wind Energy - The Facts&quot;&lt;/a&gt;, the output of an EU research programme (ISBN 9781844077106, also freely available online).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or Seguro &amp;amp; Lambert's paper &lt;a href=&quot;http://dx.doi.org/10.1016/S0167-6105(99)00122-1&quot; rel=&quot;noreferrer&quot;&gt;Modern estimation of the parameters of the Weibull wind speed distribution for wind energy analysis&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a starting point for estimation, it's usual to take $k=2$; this is equivalent to the Rayleigh distribution. However, the Weibull is more generalised, and often provides a better fit (i.e. $k$ isn't exactly 2).&lt;/p&gt;&#xA;" OwnerUserId="100" LastActivityDate="2016-03-08T13:33:23.140" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7655" PostTypeId="1" CreationDate="2016-03-09T21:10:47.720" Score="2" ViewCount="162" Body="&lt;p&gt;I am struggling to find a database or free source of joint probability of significant wave height and period, i.e. wave scatter tables. Data for buoys are useful, however not available for regions like Africa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, &lt;em&gt;oceanor&lt;/em&gt; provides software based on &lt;em&gt;hindcast&lt;/em&gt; (&lt;a href=&quot;http://www.oceanor.no/Services/Worldwaves/&quot; rel=&quot;nofollow&quot;&gt;http://www.oceanor.no/Services/Worldwaves/&lt;/a&gt;) which is not available for free. The &lt;em&gt;hindcast&lt;/em&gt; of NOAA could be used to process data from their ftp server, however it's a tedious task processing terabytes of historical data!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is another source available to public? &lt;/p&gt;&#xA;" OwnerUserId="5606" LastEditorUserId="2470" LastEditDate="2016-03-10T00:39:35.817" LastActivityDate="2016-03-10T00:39:35.817" Title="Where can I find wave scatter tables (joint probability Hs vs T) for certain coastal regions?" Tags="|ocean|waves|open-data|wave-modeling|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7657" PostTypeId="1" CreationDate="2016-03-10T07:29:24.453" Score="4" ViewCount="263" Body="&lt;p&gt;On my project, &lt;em&gt;Stability classes&lt;/em&gt; is an useful tool to analysis the weather condition for one place.        &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using R Package &lt;code&gt;Worldmet&lt;/code&gt;, I can get the hourly weather data for specific weather station based on its code at NOAA-NCDC in the world.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It contain variable like this:      &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;&quot;ws&quot;, &quot;wd&quot;&lt;/strong&gt;： wind direction and speed&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;&quot;air_temp&quot;, &quot;atmos_pres&quot;,  &quot;visibility&quot;, &quot;dew_point&quot;, &quot;RH&quot;&lt;/strong&gt;: these variables' meaning is obvious.      &lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;&quot;ceil_hgt&quot;&lt;/strong&gt;： ceiling height    &lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;&quot;cl_1&quot;, &quot;cl_2&quot;, &quot;cl_3&quot;, &quot;cl&quot;&lt;/strong&gt;: Cloud cover for different layers in Oktas (1-8)      &lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;&quot;cl_1_height&quot;, &quot;cl_2_height&quot;, &quot;cl_3_height&quot;&lt;/strong&gt;: Height of the cloud base for each later in metres.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;&quot;pwc&quot;&lt;/strong&gt;: The description of the present weather description (if available)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I want to classify the stability classes hourly based on those variables.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Referencing to the chart follows which I clipped from &lt;a href=&quot;https://www.ready.noaa.gov/READYpgclass.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA&lt;/a&gt;&lt;br&gt;&#xA;&lt;a href=&quot;http://7xrn7f.com1.z0.glb.clouddn.com/16-3-10/83493087.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://7xrn7f.com1.z0.glb.clouddn.com/16-3-10/83493087.jpg&lt;/a&gt;    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found out my variables may not support the classify job.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there some better computation way or data access to get the stability classes for one site?     &lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="94" LastEditDate="2016-03-10T09:05:08.173" LastActivityDate="2016-03-10T09:05:08.173" Title="Pasquill-Gifford stability class data for one station" Tags="|meteorology|atmosphere|atmosphere-modelling|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7659" PostTypeId="1" CreationDate="2016-03-10T16:47:30.270" Score="8" ViewCount="260" Body="&lt;p&gt;So I was browsing Google Earth the other day and I found this strange formation near Râmnicu Vâlcea, at about &lt;a href=&quot;https://www.google.ca/maps/place/R%C3%A2mnicu+V%C3%A2lcea,+Romania/@45.1032811,24.2630868,68696m/data=!3m1!1e3!4m2!3m1!1s&quot; rel=&quot;nofollow noreferrer&quot;&gt;45°07'N 24°16'E&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/luVJp.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/luVJp.jpg&quot; alt=&quot;One view&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ki8xh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ki8xh.jpg&quot; alt=&quot;Another view&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's an almost circular region, about 40 km in diameter which to my eyes looks like a multi ringed impact crater, but then again it's near a mountain chain so it could be just some random feature created by the converging tectonic plates. But what could cause the hills to be arranged in this strange manner?&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Elevation profiles&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;North-South:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/xSjjj.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xSjjj.png&quot; alt=&quot;NS profile&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;East-West&#xA;&lt;a href=&quot;https://i.stack.imgur.com/7ursO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7ursO.png&quot; alt=&quot;EW profile&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5613" LastEditorUserId="28050" LastEditDate="2018-03-05T16:44:51.010" LastActivityDate="2018-03-05T16:44:51.010" Title="What is this strange formation near Râmnicu Vâlcea?" Tags="|geology|geomorphology|mountain-building|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7660" PostTypeId="1" CreationDate="2016-03-10T23:25:51.977" Score="6" ViewCount="1550" Body="&lt;p&gt;Elements are found in different minerals and chemical compounds on earth. Oxygen is dominantly found in silicate minerals which, aside from silica, contain other elements. One way of looking at the chemical form of oxygen is to look at its bonds within the compounds. Is oxygen dominantly bonded to silicon? If so by how much and to what other elements does it most likely bond to? &lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2016-03-16T18:50:23.597" Title="What are the dominant elements that oxygen is bonded to on earth?" Tags="|geochemistry|mineralogy|petrology|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7661" PostTypeId="1" AcceptedAnswerId="7663" CreationDate="2016-03-10T23:56:53.310" Score="6" ViewCount="16872" Body="&lt;p&gt;Why can I look directly at the sun during a sunset (with a lot less pain and unconfort) but not at noon?&lt;/p&gt;&#xA;" OwnerUserId="5615" LastEditorUserId="5615" LastEditDate="2016-03-11T18:38:11.040" LastActivityDate="2016-03-31T16:42:52.787" Title="Why can I look directly at the sun during a sunset but not at noon?" Tags="|sun|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7662" PostTypeId="2" ParentId="7660" CreationDate="2016-03-11T01:05:25.367" Score="3" Body="&lt;p&gt;This answer is basically an expanded version of my comments on this &lt;a href=&quot;https://earthscience.stackexchange.com/a/7649/725&quot;&gt;answer here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you consider the crust and the mantle, then the most abundant metals are magnesium, silicon, iron, nickel, calcium, aluminium (in that order). Other notable elements would be titanium, chromium, and just about all &lt;a href=&quot;http://ruby.colorado.edu/~smyth/G30103.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;lithophile elements&lt;/a&gt;. The key is to understand that any single oxygen is not exclusively bonded to a single metal. It's bonded to several (different) metals at the same time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is an important point to be made here: because we call the minerals &quot;silicates&quot;, it's often thought that most of the stuff in there is silicon (and oxygen). In fact, there is actually more magnesium in most of the Earth. Ideal Mg-olivine (forsterite) has double the amount of magnesium than silicon. Enstatite, an orthopyroxene, has the same amount of both elements. It is a common misconception to think of oxygen as being bonded to silicon while the other metals just &quot;hop along&quot;. Silica, as SiO&lt;sub&gt;2&lt;/sub&gt; doesn't actually exist. Not in quartz and not in other silicate minerals. It's not like CO&lt;sub&gt;2&lt;/sub&gt; that exists as an independent molecule. It's just a convenient, charge-balanced way of representing oxidised silicon that has no existence if there are no oxygens around it. These oxygens are bonded to this silicon cation, but they are also bonded to everything else around it, be it magnesium or iron or whatever. An olivine is not a solid with molecules of SiO&lt;sub&gt;2&lt;/sub&gt; and MgO, it is an (almost) infinite solid with oxygens bonded to both Si&lt;sup&gt;4+&lt;/sup&gt; and Mg&lt;sup&gt;2+&lt;/sup&gt; in a three-dimensional structure. It's just a pile of cations (metals) and anions (oxygen), that happen to conform to combinations of &quot;conventional&quot; oxides because of charge balance.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-03-11T08:38:34.820" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7663" PostTypeId="2" ParentId="7661" CreationDate="2016-03-11T06:14:51.237" Score="9" Body="&lt;p&gt;At Noon, sunlight is coming from nearly directly above you, and goes through ~2 miles (4km) of reasonably dense atmosphere to reach you (Atmospheric pressure at 2 miles is about one half of sea level pressure). At sunset (and sunrise), since the sunlight is traveling mostly parallel to the surface, it travels through dense atmosphere for considerably longer. When traveling through dense atmosphere it's subjected to more &lt;a href=&quot;https://en.wikipedia.org/wiki/Diffuse_sky_radiation&quot; rel=&quot;noreferrer&quot;&gt;scattering&lt;/a&gt;, which decreases the observed intensity of the light. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or, considered a different way, when looking at a sunset/sunrise, you don't see the sun as a single well defined point. It's hazy, with the bits of sky near to the sun also giving off a fair amount of light. That additional light is some of the light that was scattered from an otherwise direct beam. If it were all re concentrated to a single point, it would be brighter/more painful to look at (though not as bright as the noon sunlight- for shaky statistical and light absorption reasons).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/J9DY4.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/J9DY4.jpg&quot; alt=&quot;Creative Commons image of a Sunset... by... Mario Antonio?&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using an &lt;a href=&quot;https://dizzib.github.io/earth/curve-calc/&quot; rel=&quot;noreferrer&quot;&gt;Earth Curvature Calculator&lt;/a&gt;, sunlight at the horizon travels through ~120 miles of 'dense' atmosphere (ie has an altitude &amp;lt;2 miles). That will fall off rather quickly the higher above the horizon the sun is. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(dense atmosphere in this refers partly to just thicker air; but also to particulates/dust in the air, haze, mist, fog, etc)&lt;/p&gt;&#xA;" OwnerUserId="5616" LastEditorUserId="5616" LastEditDate="2016-03-11T11:23:48.970" LastActivityDate="2016-03-11T11:23:48.970" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="7668" PostTypeId="1" AcceptedAnswerId="8538" CreationDate="2016-03-12T16:15:00.040" Score="3" ViewCount="725" Body="&lt;p&gt;For processing seismic data, why is &lt;a href=&quot;https://en.wikipedia.org/wiki/Seismic_Unix&quot; rel=&quot;nofollow&quot;&gt;Seismic Unix&lt;/a&gt; so important? What distinguishes it from other seismic processing software like &lt;a href=&quot;http://www.globeclaritas.com/&quot; rel=&quot;nofollow&quot;&gt;GLOBE Claritas&lt;/a&gt; or &lt;a href=&quot;http://www.software.slb.com/products/omega&quot; rel=&quot;nofollow&quot;&gt;Omega&lt;/a&gt;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it argued that processing capabilities are superior to other seismic processing software or that it is easier to use? Does it get recommended for use because of cost or its wide use?&lt;/p&gt;&#xA;" OwnerUserId="5551" LastEditorUserId="725" LastEditDate="2016-08-09T09:11:00.627" LastActivityDate="2016-08-09T09:11:00.627" Title="Seismic data processing software" Tags="|geophysics|seismology|software|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7670" PostTypeId="2" ParentId="7660" CreationDate="2016-03-12T22:13:18.333" Score="1" Body="&lt;p&gt;One of the most abundant chemicals in the outer surface of the Earth is water - where one oxygen atom bonds with two hydrogen. &lt;/p&gt;&#xA;" OwnerUserId="453" LastActivityDate="2016-03-12T22:13:18.333" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7673" PostTypeId="1" CreationDate="2016-03-13T13:56:25.637" Score="13" ViewCount="1298" Body="&lt;p&gt;I asked the same question on Physics StackExchange site. I now know that there are several types of &quot;center&quot; and I can tell, I'm interested in the CM-CF offset (CM = geocenter, CF = center of figure).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.ngs.noaa.gov/CORS/Articles/Geocenter-J-Geodyn2012.pdf&quot;&gt;Wu, Ray, and van Dam, &quot;Geocenter motion and its geodetic and geophysical implications,&quot; &lt;em&gt;Journal of Geodynamics&lt;/em&gt; 58 (2012): 44-61.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Based on Fig. 2 in the paper above, I calculated that the distance is 9 meters. However this 9 meters seems too small to me. In addition it's about &lt;em&gt;geocenter motion&lt;/em&gt;, but on he vertical axis, it says &quot;meters&quot; and not &quot;meters/year&quot; or &quot;meters / 1000 years&quot; or something similar. On Fig. 5, it's clear that Δt = 1 month. But I don't understand what's Δt for Fig. 2. If there is at all...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also found in this paper &lt;a href=&quot;http://goo.gl/pPWD8l&quot;&gt;http://goo.gl/pPWD8l&lt;/a&gt; On page 174 it says that this offset is 0.8 km. However, it's 1995 data while the other article was published in 2012.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I'm really confused now, I think I misunderstood something. I'm not a geophysicist, please help me out.&lt;/p&gt;&#xA;" OwnerUserId="5623" LastActivityDate="2023-03-16T14:10:11.387" Title="What's the distance between the center of mass and geometrical center of Earth (CM-CF offset)?" Tags="|geophysics|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7674" PostTypeId="1" CreationDate="2016-03-14T00:26:59.410" Score="5" ViewCount="23" Body="&lt;p&gt;I've been observing the current Kp Index values from this &lt;a href=&quot;http://www.gfz-potsdam.de/en/section/earths-magnetic-field/data-products-services/kp-index/definitive/&quot; rel=&quot;noreferrer&quot;&gt;site&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;At 12:18 AM UTC&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The latest measurement is 1- (the next row for 160314 hasn't been filled out yet for the next series of measurements)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;160313  1- 2- 1- 1-  0o 0o 0o 1-    4+      2 0.0&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;If the intervals go in order from 0000 - 0300, 0300 - 0600 to 2100 - 2400 then &#xA;that value is the last which makes it fall into the interval 2100 - 0000 UTC. So why is there a value present in the last interval, shouldn't it belong in the next row - to the first interval of 160314 (i.e. 0000 - 0300)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or is there some sort of delay or shift I need to take into account?&lt;/p&gt;&#xA;" OwnerUserId="5625" LastActivityDate="2016-03-14T00:26:59.410" Title="Why are Kp Index values updating at times greater that the intervals in which they belong?" Tags="|auroras|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7675" PostTypeId="2" ParentId="7434" CreationDate="2016-03-14T18:15:15.987" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;What changes in climate pattern can be observed when obliquity is at&#xA;  the extremes?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;While obliquity is easily googled, the specific effects globally aren't as easy to look up, so I'll give this one a shot.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For starters, the 41,000 year variation isn't precise.  It fluctuates some, having to do with the earth and other planets not being perfect spheres and not all orbiting in the same plane of elliptic, and the planets (Primarily Jupiter), tugging on each other.   The Moon stabilizes the Earth's obliquity somewhat, though that's often overstated.  More recent models have shown that the Earth's obliquity would be reasonably stable even without the moon and in the future, the Moon could fall into resonance that will destabilize the Earth's obliquity.  (I read that researching another question,  but don't have the article handy and that doesn't really apply to your question anyway).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The easy part to look up is that Obliquity is primarily a polar and seasonal effect.  Higher Obliquity (24.5% currently and the more extreme 30% proposed in your question) means colder winters and hotter summers in higher latitudes.  (higher latitude means both poles, just for clarity, high latitude = far from equator)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;High obliquity means more extreme seasonality (hotter summers and colder winters in both hemispheres). This does not change the year-average energy reaching the Earth, but in terms of temperature the Northern hemisphere is more important because it contains more land: Land warms up faster than water and it also hosts the reflective ice-sheets that contribute to Earth's cooling. As a result, Ice ages (somewhat) coincide with cold Northern Summers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, the simplified answer is higher obliquity, hotter earth, lower obliquity, colder earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles#Axial_tilt_.28obliquity.29&quot; rel=&quot;nofollow&quot;&gt;Source - Milankovich&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quote:  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The tilt is in the decreasing phase of its cycle, and will reach its&#xA;  minimum value around the year 11,800 CE ; the last maximum was reached&#xA;  in 8,700 BCE. This trend in forcing, by itself, tends to make winters&#xA;  warmer and summers colder (i.e. milder seasons), &lt;strong&gt;as well as cause an&#xA;  overall cooling trend&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and &lt;a href=&quot;http://www.ncdc.noaa.gov/paleo/milankovitch.html&quot; rel=&quot;nofollow&quot;&gt;Source - NOAA Article&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;less &quot;tilt&quot; means less severe seasons - cooler summers and milder&#xA;  winters. The earth wobbles in space so that its tilt changes between&#xA;  about 22 and 25 degrees on a cycle of about 41,000 years. &lt;strong&gt;It is the&#xA;  cool summers which are thought to allow snow and ice to last from year&#xA;  to year in high latitudes, eventually building up into massive ice&#xA;  sheets.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;you asked:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How extreme can the climate get if the obliquity oscillates between 20&#xA;  and 30 degrees?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;With a 20 to 30 degree variation in tilt, figuring the same 41,000 year cycle, Ice would build up in the North as the cycle leaned towards 20 degrees and ice would melt in the North as the cycle leaned towards 30 degrees.  The &quot;milder winter&quot; that we might expect from a 20 degree tilt would be highly overcompensated for by the cooling effect of an ice sheet if there was an ice sheet, so, &quot;milder at lower tilt&quot;, shouldn't be taken as strictly true but only true if there isn't an ice age coinciding with the lower tilt.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's possible a 30 degree tilt, which would cycle upwards, 28 29, 30, 29, 28), that period of high tilt, lasting 10,000 years might be enough to melt Antarctica too, which for the most part hasn't melted in 15-25 million years or so.   Needless to say, with a tilt that high, we'd probably go through more extreme variation with the rise and fall of ice ages and rapidly changing sea level, and ice age cycles are already quite extreme in terms of sea level rise, flooding from glacial melt melt and other changes.   Anyone who was alive 12,000 - 8,000 years ago could verify that the changes were intense.  Fossil records show an increase in extinctions during periods of rapid climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The last maximum tilt happened 8,700 BCE, so the moving towards the maximum coinciding quite well with the end of the last ice age and the minimum is going to happen about 11,800 CE (or 11,800 AD for anyone who went to school when I did), and that (might) coincide with the rising of the next ice age, but it's a bit more complicated than that, as we've figured out how to stop ice ages by burning lots of fossil fuels, and the other orbital factors would need to be considered as well.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's the simplified answer anyway.  A more detailed answer would take into account the other orbital cycles (see Milankovich link above), the &lt;a href=&quot;https://en.wikipedia.org/wiki/100,000-year_problem&quot; rel=&quot;nofollow&quot;&gt;100,000 year problem&lt;/a&gt; and the large permanent glaciers which survive the entire 41,000 year cycle, such as we currently have on Greenland and Antarctica and which affect albedo.  I might try to tie that in later, but that would get longer and at my level of understanding, a bit less certain.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="1379" LastEditDate="2016-03-15T16:57:55.263" LastActivityDate="2016-03-15T16:57:55.263" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7677" PostTypeId="2" ParentId="6527" CreationDate="2016-03-15T19:35:06.183" Score="-2" Body="&lt;p&gt;The melting polar ice definitely absorbs a significant amount of energy,&#xA;maybe not as much as the oceans do, but critical here is that the energy&#xA;absorbed is latent energy HIDDEN heat, and does not show up on the big&#xA;thermometer, and also exhibits positive feedback, i.e., less reflection and&#xA;more absorption, Therefore the melting ice is very important and scary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another less talked about topic, increasing atmospheric water&#xA;vapor, another source of latent HEAT, with positive feedback, $H_2O$ is&#xA;a powerful greenhouse gas, very scary, VERY SCARY indeed.&lt;/p&gt;&#xA;" OwnerUserId="5632" LastEditorUserId="2470" LastEditDate="2018-09-03T14:16:52.613" LastActivityDate="2018-09-03T14:16:52.613" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="7678" PostTypeId="1" CreationDate="2016-03-16T00:04:06.460" Score="1" ViewCount="376" Body="&lt;p&gt;What is the earth's core temperature and is it really directly related to the earth's mantle?  &lt;/p&gt;&#xA;" OwnerUserId="5633" LastEditorUserId="111" LastEditDate="2016-03-16T16:32:44.667" LastActivityDate="2016-03-16T16:32:44.667" Title="What is the earth's core temperature?" Tags="|temperature|mantle|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7679" PostTypeId="2" ParentId="7678" CreationDate="2016-03-16T00:26:45.997" Score="6" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Inner_core&quot;&gt;inner core&lt;/a&gt; of the Earth is a large sphere of nickel-iron alloy. Surrounding this is the molten inner core which has a temperature of approximately 5400 ℃.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Geothermal_gradient&quot;&gt;source of heat&lt;/a&gt; that keeps the Earth's core hot and molten is the decay of radioactive elements, predominantly uranium, thorium and potassium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Mantle and Crust act as insulators for the Earth's Core.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-03-16T00:26:45.997" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7680" PostTypeId="1" AcceptedAnswerId="7693" CreationDate="2016-03-16T06:38:55.780" Score="7" ViewCount="263" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ICXq4.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ICXq4.png&quot; alt=&quot;Slit in the north coast of Jersey&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have this photo as a background image and I often wonder how such a narrow, well-defined slit could be formed. Is it natural or man-made? If natural, what processes could have formed it? The rest of the coastline is rugged but this appears very uniform. It is on the north-west coast of Jersey (UK).&lt;/p&gt;&#xA;" OwnerUserId="5636" LastEditorUserId="94" LastEditDate="2016-03-16T09:29:00.327" LastActivityDate="2016-03-17T00:43:47.237" Title="What causes such a narrow slit in a cliff? (see photo)" Tags="|geology|geomorphology|coastal|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7681" PostTypeId="1" AcceptedAnswerId="7694" CreationDate="2016-03-16T17:24:23.820" Score="5" ViewCount="497" Body="&lt;p&gt;I understand that large mountain ranges like the Rockies are created by the tectonic plates moving. I live in Arizona and there are a lot of mountains here but from what I understand, there are no plate faults here. How are the small mountain ranges are created?&lt;/p&gt;&#xA;" OwnerUserId="5638" LastEditorUserId="725" LastEditDate="2016-03-17T08:08:07.927" LastActivityDate="2017-01-28T01:04:19.183" Title="How are small mountains created?" Tags="|plate-tectonics|mountains|orogeny|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7682" PostTypeId="1" AcceptedAnswerId="7683" CreationDate="2016-03-16T16:52:27.783" Score="8" ViewCount="621" Body="&lt;p&gt;Taking for example the attached image, when looking at the ocean floor, there appears to be areas (strips, some of which I have drawn red lines by) of greater detail. Is this accurate detail? From ships that have passed over the area?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/7XqkT.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7XqkT.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5640" OwnerDisplayName="Al Lelopath" LastEditorUserId="5640" LastEditDate="2016-03-16T19:26:20.900" LastActivityDate="2016-03-17T09:15:45.390" Title="Details on Ocean floor" Tags="|topography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7683" PostTypeId="2" ParentId="7682" CreationDate="2016-03-16T18:37:36.937" Score="11" Body="&lt;p&gt;&lt;strong&gt;Those are &lt;a href=&quot;http://seabedhabitats.org/2014/02/16/multibeam-backscatter-vs-sidescan-sonar-imagery/&quot; rel=&quot;nofollow noreferrer&quot;&gt;bathymetric survey&lt;/a&gt; tracks.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The survey artifacts are very straight and regular in character, compared to geological features. What you're seeing is an increased level of detail along the survey line, which contrasts with the relatively smooth background model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I labeled some of the features in &lt;a href=&quot;https://earthscience.stackexchange.com/a/6548/70&quot;&gt;this answer&lt;/a&gt; to a related question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ceZqX.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ceZqX.jpg&quot; alt=&quot;Labeled image of Pacific floor&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NOAA Reference: &lt;a href=&quot;http://oceanservice.noaa.gov/facts/atlantis.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Did I find the lost underwater civilization of Atlantis?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-03-17T09:15:45.390" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7684" PostTypeId="2" ParentId="7660" CreationDate="2016-03-16T18:50:23.597" Score="2" Body="&lt;p&gt;As mentioned, if you mean Earths crust, then it is bonded mostly to Si and Al (quartz, feldpspars, then other silicates, water, iron oxides etc.). If you mean a whole Earths body, then crust is just a minuscule part compared to mantle - the details are in the previous response. We think that mantle consists of olivine, spinel group etc. Actually recent research suggest much higher water content in the mantle then previously anticipated. But keep in mind that we have no direct evidence of what really is inside the mantle or core. &lt;/p&gt;&#xA;" OwnerUserId="5639" LastActivityDate="2016-03-16T18:50:23.597" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7686" PostTypeId="2" ParentId="7680" CreationDate="2016-03-16T19:12:04.033" Score="1" Body="&lt;p&gt;Could be formed by two natural processes. First, some fault with shear zone, which is obviously much weaker than the rock around it and gots weathered faster. Second, could be some vein/dyke of some mineral or rock softer than surrounding rocks. &lt;/p&gt;&#xA;" OwnerUserId="5639" LastActivityDate="2016-03-16T19:12:04.033" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7687" PostTypeId="2" ParentId="4312" CreationDate="2016-03-16T20:13:13.797" Score="2" Body="&lt;p&gt;Actually, according to IMA classification rules, only albite and anorthite are valid placioglace group mineral names. The content can be easily constructed from Ca/Na ratio. There are more ways to do that but the most simple is the use of &lt;em&gt;apfu (atoms per formula unit)&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let say we have theoretical feldspar with composition K0.1Na0.3Ca0.6Al1.2Si3O8 - so you have 0.1 K, 0.3 Na and 0.6 Ca in one feldspar molecule. Together its 1 so we can directly recalculate that into %. So it has (0.1 x 100 =) 10% K-feldspar, 30% albite and 60% anorthite. By modern classification this is anorthite. By the old classification (still &#xA; used in petrology) its labradorite. The 50 % rule applies so basically what is over 50% ir right. Over 0.5 Na is albite, over 0.5 is anorthite. If there is also some K present, rarely both Na and Ca might be less then 0.5 - then the bigger number wins. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have real data, you rarely have such ideal composition. But you can get the % of each component from equation (apfu of alkali metal/sum of all alkali metals apfu) x 100. So e.g. [0.256 Na/(0.256 Na + 0.035 K + 0. 723 Ca)] x 100 gives you the % of albite component. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The miscibility of Ca-plagioclase with K-feldspar is quite poor while albite (Na-plagiocalse) can contain some more K-feldspar component. More about miscibility and origin of feldspars &lt;a href=&quot;http://www.mineralexpert.org/overview-plagioclases-feldspars.php&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;. The miscibility strongly depends also on temperature. Also rare Ba-feldspars exist, more in the reference.   &lt;/p&gt;&#xA;" OwnerUserId="5639" LastActivityDate="2016-03-16T20:13:13.797" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7688" PostTypeId="1" CreationDate="2016-03-16T20:21:51.077" Score="4" ViewCount="1728" Body="&lt;p&gt;Are there any good open source (Linux) alternatives of &lt;code&gt;SeisImager&lt;/code&gt; which includes Pickwin and Plotrefa and file formats are .sg2?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Same question for &lt;code&gt;RES2DINV&lt;/code&gt;?&lt;/p&gt;&#xA;" OwnerUserId="3309" LastEditorUserId="725" LastEditDate="2017-01-28T01:02:56.640" LastActivityDate="2017-02-09T01:37:28.720" Title="Good Open source alternatives to SeisImager &amp; RES2DINV?" Tags="|seismology|software|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7689" PostTypeId="2" ParentId="174" CreationDate="2016-03-16T21:16:24.090" Score="4" Body="&lt;p&gt;One more trick - felsic magmas are basically fractionated derivates of other rocks. During the rock cycle, the most volatile components tend towards the felsic rocks. Water and fluxes generally reduce the melting point. And felsic rocks usually have alkalis compared to Fe/Mg in mafic rocks. Alkalis are more reactive and volatile. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you partially melt mafic rocks, the most reactive and volatile components are in the first melt. If it gets removed from the source, you get more fractionated and felsic melt. Repeat many times and you get extremely fractionated melt with minimum mafic components and high content of volatiles and highly reactive elements like alkalis or fluorine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fluxes like water, boron, phosphorus, fluorine etc. can strongly reduce melting point. E.g. dry haplogranite barely melts at 700 Celsius while some pegmatite melts with extreme water and volatiles content can obviously exist bellow 500 Celsius. Dry anorogenic granites or ryolites have much higher melting point then some wet S-type granites.   &lt;/p&gt;&#xA;" OwnerUserId="5639" LastActivityDate="2016-03-16T21:16:24.090" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7690" PostTypeId="1" CreationDate="2016-03-16T21:25:44.513" Score="16" ViewCount="10472" Body="&lt;p&gt;Of course we receive less sunlight in winter, because the sun is lower in the sky, so the light has to travel through more atmosphere, and loses strength. Does this mean that the blue light is more scattered out? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are the frequencies we receive in the winter relatively the same as in summer or is there a change in the received spectrum? Are there less UV-B rays in winter than there are in summer relative to UV-A? If so what is the cause of that?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="56" LastEditDate="2016-03-21T05:00:19.633" LastActivityDate="2021-07-29T22:26:19.963" Title="Is spectrum of sunlight the same in the summer as in the winter?" Tags="|meteorology|atmospheric-radiation|light|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7691" PostTypeId="2" ParentId="7475" CreationDate="2016-03-16T22:27:27.237" Score="2" Body="&lt;p&gt;To make it even more difficult, recent research revealed existence of microdiamonds. Tiny diamonds (microscopic) were discovered inside kyanite or garnet within granulite rocks. So our explanation for diamond formation is at least partially wrong (they form at much lower pressure then anticipated) or we have some problems with understanding of granulites and subduction mechanisms - can we drag a granulite precursor 150+ km into the mantle without melting it? See one of the recent &lt;a href=&quot;https://www.researchgate.net/publication/262807235_First_finding_of_microdiamond_coesite_and_other_UHP_phases_in_felsic_granulites_in_the_Moldanubian_Zone_Implications_for_deep_subduction_and_a_revised_geodynamic_model_for_Variscan_Orogeny_in_the_Bohe&quot; rel=&quot;nofollow&quot;&gt;papers&lt;/a&gt;. You can also check some less scientific &lt;a href=&quot;http://www.mineralexpert.org/diamond-king-of-gems.php&quot; rel=&quot;nofollow&quot;&gt;diamond overview&lt;/a&gt;.   &lt;/p&gt;&#xA;" OwnerUserId="5639" LastActivityDate="2016-03-16T22:27:27.237" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7693" PostTypeId="2" ParentId="7680" CreationDate="2016-03-17T00:43:47.237" Score="6" Body="&lt;p&gt;If you see the other user (Jan Doggen's) google maps link, you can see apparently similar features in different states - this is a particularly neat example of a general phenomenon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These notches form when headlands are undercut by caves carved out by the sea. They may be initiated where there is a fault or jointing in the rock (northwest Jersey is granite, according to google). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this particular case, the notch seems to have a rounded termination. Blowholes also form from undercutting of headlands producing caves whose roofs then collapse. It's possible this cave may have collapsed after a blowhole formed, so you get a notch where the inland end of the feature appears rounded. That bit is just speculation though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found this Jersey geology trail guide that might have more detail: &lt;a href=&quot;http://jerseygeologytrail.net/Geomorph.shtml&quot;&gt;http://jerseygeologytrail.net/Geomorph.shtml&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5644" LastActivityDate="2016-03-17T00:43:47.237" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7694" PostTypeId="2" ParentId="7681" CreationDate="2016-03-17T01:59:46.250" Score="5" Body="&lt;p&gt;There are no plate faults in Arizona (actually &quot;plate boundary&quot; is the term that we use - &quot;fault&quot; already has a different meaning, so it could be confusing), but there is still extension of the continental crust. The southern half of Arizona has part of the Basin &amp;amp; Range province, which stretches from Oregon to the south of Mexico.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you imagine holding a peice of slightly brittle rubber and having someone push up from beneath it, you get cracks in the rubber where it stretches. This is happening to the North American continent. The 'ranges' in &quot;Basin &amp;amp; Range&quot; are the ridges in the rubber, the 'basins' are the cracks. (Exactly why/how this part of North America was pulled apart/pushed up is a subject of intense debate among geologists.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can intuitively see how these ranges would not be as high as the Rockies, which formed from a plate of oceanic crust (denser, heavier, thinner) being pulled/pushed underneath the contnental crust (lighter, fluffier, much thicker), causing continental rock to A) bunch up, and B) melt as water is added to it, leading to magma rising and bulging upward into volcanic chains. (Another factor controlling mountain height is erosion, so the Rockies, which are 80 million years old, are lower than the Andes, which are formed a similar way, but which are still being pushed upwards.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Himalayas are different again - instead of oceanic crust meeting contnental crust, this was contnental crust meeting more contnental crust, so instead of one side going underneath another, neither side will sink, they're both too light, so they cram into each other creating much higher mountains than either the Rockies or the Andes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just doing some quick googling, it sounds like Arizona also has both volcanic feature and eroded remnants of volcanic features. These kinds of mountains/hills are formed via a different method again, and their heights are controlled by their own method of formation. Volcanoes can vary a lot in height. They can be very small, like the volcanoes in south-east Australia where I live, or very large, like the volcanoes in the Andes mountain range, or they can be large, but broad and flat, like Hawai'i.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Erosion can carve out softer rock and leave behind more resistant stuff, and this is how some smaller hills/mountains are formed (like Uluru in central Australia). I found this online which might lead you in some interesting directions: &lt;a href=&quot;http://www.janrasmussen.com/pdfs/geol_hist_az_Rasmussen_2012%20preprint.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geologic History of Arizona By Jan C. Rasmussen&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5644" LastEditorUserId="725" LastEditDate="2017-01-28T01:04:19.183" LastActivityDate="2017-01-28T01:04:19.183" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7696" PostTypeId="1" AcceptedAnswerId="7697" CreationDate="2016-03-17T05:16:30.650" Score="6" ViewCount="12293" Body="&lt;p&gt;From a dissertation, I read about the greenhouse gas's effect which make the surface warmer.  It says, I quote:  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The greenhouse effect results in an average surface temperature of approx. $14^\circ\ \rm C$, compared to  $-19^\circ\ \rm C$ if the atmosphere would have been transparent to thermal radiation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Is there some simple way to estimate the average temperature of Earth's surface using some  parameters like sunlight intensity?  &lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="725" LastEditDate="2017-01-28T01:00:05.403" LastActivityDate="2017-01-28T01:00:05.403" Title="How to calculate the temperature of Earth's surface" Tags="|meteorology|atmosphere|climate|climate-change|greenhouse-gases|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7697" PostTypeId="2" ParentId="7696" CreationDate="2016-03-17T13:35:25.617" Score="7" Body="&lt;p&gt;An easy calculation is to start with the solar constant, the power (energy per unit time) produced by solar radiation at a distance of one astronomical unit. This is 1.361 kilowatts per square meter. The surface area of the Earth is $4\pi R^2$, where $R$ is the radius of the Earth, while the cross section of the Earth to solar radiation is $\pi R^2$. Thus the Earth as a whole receives 1/4 of that solar constant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assume a planet with an atmosphere that is transparent in the thermal infrared, with the same albedo as that of the Earth (0.306), rotating rapidly like the Earth, and orbiting at the same distance from the Sun as the Earth. The effective temperature of this planet is given by the Stefan Boltzmann law:&#xA;$$T = \left(\frac{(1-\alpha)\,I_\text{sc}}{4\sigma}\right)^{1/4}$$&#xA;where&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$\alpha$ is the albedo (0.306),&lt;/li&gt;&#xA;&lt;li&gt;$I_\text{sc}$ is the solar constant (1.361 kW/m&lt;sup&gt;2&lt;/sup&gt;),&lt;/li&gt;&#xA;&lt;li&gt;$\sigma$ is the Stefan Boltzmann constant (5.6704×10&lt;sup&gt;−8&lt;/sup&gt; W/m&lt;sup&gt;2&lt;/sup&gt;/K&lt;sup&gt;4&lt;/sup&gt;), and&lt;/li&gt;&#xA;&lt;li&gt;the factor of 1/4 arises from the the fact that the Earth is a rapidly rotating spherical object.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The result is &lt;a href=&quot;http://www.wolframalpha.com/input/?i=&amp;#40;&amp;#40;&amp;#40;1-0.306&amp;#41;*&amp;#40;1.361+kilowatts+per+square+meter&amp;#41;&amp;#41;%2F&amp;#40;4*&amp;#40;stefan+boltzmann+constant&amp;#41;&amp;#41;&amp;#41;%5E&amp;#40;1%2F4&amp;#41;&quot;&gt;-19 °C&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2016-03-17T13:35:25.617" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7698" PostTypeId="1" AcceptedAnswerId="7750" CreationDate="2016-03-17T15:01:16.247" Score="10" ViewCount="1034" Body="&lt;p&gt;I'm a user of WRF V3.5 aiming at  meteorological simulation.&lt;br&gt;&#xA;Sometimes, I'll run the model &lt;em&gt;for a long period&lt;/em&gt;.     &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;My attempt&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;I split the long period(e.g 1 year) into serval short ones.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example:    &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt; ## WPS namelist.wps      &#xA; start_date = '2014-01-01_06:00:00'&#xA; end_date   = '2014-01-31_23:00:00'  &#xA;&#xA; ## WRF run period setting in .csh file.    &#xA; set year = &quot;2014&quot;&#xA; foreach strtime (010106010512 010500011012 011000011512 011500012012 012000012512 012500013012 013000020100)&#xA;&#xA; set smon = `echo ${strtime}|cut -c1-2`&#xA; set sday = `echo ${strtime}|cut -c3-4`&#xA; set shr  = `echo ${strtime}|cut -c5-6`&#xA; set emon = `echo ${strtime}|cut -c7-8`&#xA; set eday = `echo ${strtime}|cut -c9-10`&#xA; set ehr  = `echo ${strtime}|cut -c11-12`  &#xA;&#xA; &amp;amp;time_control&#xA; run_days                            = 0,&#xA; run_hours                           = 132,&#xA; run_minutes                         = 0,&#xA; run_seconds                         = 0,&#xA; start_year                          = ${year},${year},&#xA; start_month                         = ${smon},${smon},&#xA; start_day                           = ${sday},${sday},&#xA; start_hour                          = ${shr},${shr},&#xA; start_minute                        = 00,00,&#xA; start_second                        = 00,00,&#xA; end_year                            = ${year},${year},&#xA; end_month                           = ${emon},${emon},&#xA; end_day                             = ${eday},${eday},&#xA; end_hour                            = ${ehr},${ehr},&#xA; end_minute                          = 00,00,&#xA; end_second                          = 00,00,&#xA; interval_seconds                    = 21600&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;In these short period, I set the first 12-h as the spinning period(except the start one.)        &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the schematics of the temporal  modeling setup which I clipped from the Internet.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://i12.tietuku.cn/afd906ddd823ddd6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://i12.tietuku.cn/afd906ddd823ddd6.png&lt;/a&gt;   &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Result&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;It generate 8 .nc file which each contain 132 frames of data.&lt;br&gt;&#xA;For now, I use the &lt;strong&gt;The netCDF Operators(NCO)&lt;/strong&gt; to deal with the output files.     &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Using &lt;code&gt;ncks&lt;/code&gt; to delete the first 12-h frames for each file separately.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Using &lt;code&gt;ncrcat&lt;/code&gt;to concat all 8 .nc files together to get one file represent the whole simulation period.   &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;h3&gt;Problem&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;I was using this method for a while. But when the amount of files are huge, it really a dump approach.      &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Are there someone offering your approaches to dealing with spin-up data deletion?&lt;/strong&gt;      &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;My target&lt;/h3&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The model can generate only one file which contain all the simulation period.   &lt;/li&gt;&#xA;&lt;li&gt;The spin-up time can be covered by last file's frames automatically. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h3&gt;Update: Wish you share your approaches!&lt;/h3&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="5214" LastEditDate="2016-03-29T02:47:30.477" LastActivityDate="2016-03-29T02:47:30.477" Title="Technique to delete spin-up frames from WRF" Tags="|meteorology|atmosphere|models|atmosphere-modelling|wrf|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7699" PostTypeId="2" ParentId="7688" CreationDate="2016-03-17T19:18:13.043" Score="3" Body="&lt;p&gt;I can address the Res2DInv. The answer unfortunately is no. The only freely available Resistivity Inversion software is R2 or R3 from Lancaster University. &lt;a href=&quot;http://www.es.lancs.ac.uk/people/amb/Freeware/R2/R2.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.es.lancs.ac.uk/people/amb/Freeware/R2/R2.htm&lt;/a&gt;. This software is only free for students and projects that don't have a commercial component. The author of the software charges about as much as RES2DINV for commercial applications. Last I checked all of these programs are precompiled for Windows. You may be able to use a windows virtual machine in linux. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Check out Simpeg as well. It is a python library for Geophysical Modeling built by UBC. It is comprehensive and has routines for resistivity, em, mag, etc.&#xA;&lt;a href=&quot;http://simpeg.xyz/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://simpeg.xyz/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seismic Unix or Madagascar are big packages that might have what you need to do the same sorts of operations as SeisImager. There is also Opendtect for interpretation and visualization. Ask @kwinkunks for more information on the seismic end of things. He has a more comprehensive list of open source geoscience software.&lt;/p&gt;&#xA;" OwnerUserId="5612" LastEditorUserId="5612" LastEditDate="2017-02-09T01:37:28.720" LastActivityDate="2017-02-09T01:37:28.720" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7700" PostTypeId="1" CreationDate="2016-03-17T21:18:38.213" Score="5" ViewCount="8276" Body="&lt;p&gt;What would happen if a Richter magnitude 13 earthquake occurred? I read (at &lt;a href=&quot;http://www.tulane.edu/~sanelson/Natural_Disasters/impacts.htm&quot; rel=&quot;noreferrer&quot;&gt;http://www.tulane.edu/~sanelson/Natural_Disasters/impacts.htm&lt;/a&gt;; about halfway down the page) that if a comet were to ever hit Earth, it would create a Richter magnitude 13 earthquake.&lt;/p&gt;&#xA;" OwnerUserId="5642" LastEditorUserId="5293" LastEditDate="2016-03-20T03:44:58.347" LastActivityDate="2021-11-15T19:46:10.990" Title="What happens if a magnitude 13 earthquake occurs?" Tags="|earthquakes|meteorite|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="7701" PostTypeId="1" AcceptedAnswerId="7715" CreationDate="2016-03-17T21:19:26.973" Score="5" ViewCount="386" Body="&lt;p&gt;I'm looking for a graph of improvements in spatial resolution for any atmospheric model (such as the &lt;a href=&quot;http://www.metoffice.gov.uk/research/modelling-systems/unified-model&quot; rel=&quot;nofollow&quot;&gt;UK Met Office Unified Model&lt;/a&gt; or &lt;a href=&quot;http://www.ecmwf.int/en/research/modelling-and-prediction&quot; rel=&quot;nofollow&quot;&gt;ECMWF IFS&lt;/a&gt;).  Ideally it would include a range of historical model versions and perhaps forecasts for future model resolutions.&lt;/p&gt;&#xA;" OwnerUserId="183" LastEditorUserId="192" LastEditDate="2016-03-20T21:33:29.403" LastActivityDate="2016-03-21T04:30:24.863" Title="Timeline of atmospheric model resolution" Tags="|models|nwp|reference-request|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7702" PostTypeId="1" AcceptedAnswerId="7708" CreationDate="2016-03-17T21:29:56.520" Score="1" ViewCount="181" Body="&lt;p&gt;What happens if an Ice Age or Interglacial Period Cycle starts? I don't know what exactly what happened then.&lt;/p&gt;&#xA;" OwnerUserId="5642" LastEditorUserId="11908" LastEditDate="2019-03-13T05:11:20.313" LastActivityDate="2019-03-13T05:11:20.313" Title="Ice Age/Interglacial Period Cycle" Tags="|glaciology|ice-age|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7704" PostTypeId="1" AcceptedAnswerId="7706" CreationDate="2016-03-18T13:51:18.997" Score="9" ViewCount="896" Body="&lt;p&gt;I have been studying/working with Wind Energy for a while and, one of my main responsabilities right now is to search for adequate &lt;strong&gt;long-term wind speed forecasting models&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, 2 things strike me about this quest.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Wind speed forecasting is a task of great complexity for wind speed itself is highly stochastic. It depends on climate patterns, regional weather behavior, topography and atmospheric stability, or the lack of thereof, just to mention a few. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The very own idea of &quot;long-term&quot; varies from researcher to researcher. So far I've found authors who claim that 1 to 7 days can be considered long-term &lt;em&gt;(Current status and future advances for wind speed and power forecasting,Jung &amp;amp; Broadwater, 2014)&lt;/em&gt;; but also those who say one full year is the minimum threshold for long-term forecasting &lt;em&gt;(The quality of weather information for forecasting of intermittent renewable generation, Sokolowska &amp;amp; Hossa, 2014)&lt;/em&gt;. It's clear that forecasting horizon is highly linked to the aim of your research; therefore, when topics change, so will their forecasting horizons.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;a.&lt;/strong&gt; Isn't there a consensus about what long term means when it deals with wind speed forecasting?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;b.&lt;/strong&gt; Can it be assumed year(s)-long wind speed forecasting withsignificant accuracy  is still some far-fetched, wishful thinking?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;c.&lt;/strong&gt; What are some efficient models out there yielding meaningful results?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to hear your ideas/points as long as they can be backed by scientific reasoning. If you could point me out in the direction of research (proofs to your rationale) in long-term wind forecasting, I'd be downright grateful.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In case you have worked with this topic, then I'd enjoy hearing from your own experience. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you so much in advance for all inputs. &lt;/p&gt;&#xA;" OwnerUserId="5301" LastActivityDate="2016-03-19T09:04:29.697" Title="Long-term Wind Speed Forecasting: reality or wishful thinking?" Tags="|meteorology|models|wind|weather-forecasting|climatology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7705" PostTypeId="2" ParentId="7704" CreationDate="2016-03-18T17:43:07.597" Score="1" Body="&lt;p&gt;Wind can be an incredibly localized phenomena, both in the short term and the long term. Although the broad outlines of a long-term wind forecast shouldn't be too complex or controversial, getting the details right will generally require actual on-site measurement. Google &lt;a href=&quot;https://www.google.com/search?q=wind%20monitor%20sodar&quot; rel=&quot;nofollow&quot;&gt;wind measurement sodar&lt;/a&gt; for some cool tools to do such measurement.&lt;/p&gt;&#xA;" OwnerUserId="534" LastActivityDate="2016-03-18T17:43:07.597" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7706" PostTypeId="2" ParentId="7704" CreationDate="2016-03-18T21:27:09.057" Score="9" Body="&lt;p&gt;Warning: &quot;long-term wind-speed forecasting for generation&quot; has (at least) two very different meanings. One refers to forecasting a distribution of wind speeds; the other refers to hour-by-hour (or half-hour by half-hour) forecasting of wind speeds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Generally, when we talk about long-term forecasting of wind speeds for wind generation, we're talking about estimating the distribution of wind speeds over the next few years. That is to say, we're not talking about what the wind speed will be exactly two years from today, at 15.00 UTC. We're talking about what the shape of the distribution of the wind speeds will be - maybe in terms of the two parameters of a Weibull distribution, together with some indication of how the distribution varies by time of day, and by season of the year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is some skill in hour-by-hour wind speed forecasts up to about two weeks away. But for longer than that, there's very little skill in the models at all. In that regard, if we are talking about hour-by-hour wind speed forecasts, then short term is the next 0.5 - 4 hours, and long-term is 1-2 weeks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In both cases, I'd look at recent publications from Reading University - &lt;a href=&quot;http://centaur.reading.ac.uk/view/creators/90000618.html&quot;&gt;David Brayshaw&lt;/a&gt; and &lt;a href=&quot;http://www.reading.ac.uk/energy/ene-publications.aspx&quot;&gt;others&lt;/a&gt; - and specifically on the accuracy of wind forecasts for wind generation, I'd also recommend work by &lt;a href=&quot;http://www.dtu.dk/english/Service/Phonebook/Person?id=1559&amp;amp;tab=2&amp;amp;qt=dtupublicationquery#tabs&quot;&gt;Henrik Madsen&lt;/a&gt; and &lt;a href=&quot;http://pierrepinson.com/&quot;&gt;Pierre Pinson&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="100" LastEditDate="2016-03-19T09:04:29.697" LastActivityDate="2016-03-19T09:04:29.697" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7707" PostTypeId="1" CreationDate="2016-03-18T21:32:45.257" Score="9" ViewCount="2905" Body="&lt;p&gt;I'm posting here to get some more expert information based on &lt;a href=&quot;https://worldbuilding.stackexchange.com/questions/38317/if-the-earth-gradually-stopped-spinning-what-would-the-changes-look-like-in-20/38331#38331&quot;&gt;this question&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the Earth were to stop rotating, removing the centrifugal force causing the equatorial bulge, how long would it take for the mantle and crust to return to hydrostatic equilibrium?  That is, immediatly, thousands of years, or millions of years?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Never mind that changing the rotation in reality would involve forces and timescales that would not really provide this condition. &lt;em&gt;if&lt;/em&gt; matter were arranged in such a shape, how long (orders of magnitude) would it take to settle?&lt;/p&gt;&#xA;" OwnerUserId="5655" LastEditorUserId="-1" LastEditDate="2017-04-13T12:52:35.360" LastActivityDate="2016-05-30T17:51:39.543" Title="How viscous is the Earth's mantle?" Tags="|geophysics|mantle|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7708" PostTypeId="2" ParentId="7702" CreationDate="2016-03-18T21:35:33.153" Score="2" Body="&lt;p&gt;I'm guessing this has been answered before, but in a nutshell, the primary mechanism over the last 3 million years or so is nothing more than colder summers in the Northern Hemisphere.  Now, one cold summer won't do it, you need hundreds, which usually requires an orbital variation or perhaps, ocean current change or perhaps an extended solar minimum, but the effect needs to last for at least for a few to several centuries, or something radical like a dinosaur killing meteor or a once in a million years volcano, but that's more of an extreme event and not relevant to your question.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's places in the far north that are snow covered year round.  Some of the time it gets warm enough for snow and ice to melt, but where it doesn't stay warm enough for all the ice to melt, you get ice cover 365 days a year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you get an extended period of colder summers, then the ice cover can move south, covering more land in the Northern Hemisphere.   (The South pole isn't as important because the land near the south pole is already ice covered and that pretty much never changes).   As the ice moves south and covers more land, a few things happen, often referred to as feedback mechanisms. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) more sunlight reflects off ice, less heat stays on the Earth to warm the atmosphere, this has a global cooling effect.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Oceans begin to fall as ice builds up on land.  Oceans absorb the most heat from the sun per square meter out of any surface on earth.  Ocean heat absorption also evaporates water vapor into the atmosphere, and water vapor acts as a greenhouse gas.  As oceans fall, they also cover less area and while the size change is a relatively small percentage, that also works to cool the earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) as the ice grows higher, this has a cooling effect on high altitude air, which blows off the ice and cools surrounding areas and tends to keep the ice frozen longer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;4) as the oceans grow cooler, they absorb CO2 from the air, this lowers the amount of greenhouse gas in the air which has a cooling effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cooler northern summers are thought to be driven by orbital changes such as low orbital eccentricity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Interestingly, the effects such as orbital variations, milder summers and even CO2 are by themselves, quite small, but when taken together with the feedback mechanisms in place, the temperature change of the planet between ice age and inter-glacial period is quite large.  As much as 10 degrees c globally, corresponding with mile high glaciers covering most of Canada, half the United States, half of Russia and Europe, as well as 300 foot sea level drops and ecosystem changes around the globe.   Not all bad.  Some deserts will arguably get improved ecosystems, but the change is felt globally.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The inter-ice age period is the same thing just in reverse.  Orbital changes can lead to warmer summers which melts ice, and beings to reverse the 4 feedback mechanisms mentioned above.   Melting ice isn't all harmless though.  You get enormous lake sized pockets of water trapped in ice, waiting to give way, and floods like we've never seen.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2016-03-18T21:35:33.153" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7710" PostTypeId="2" ParentId="7113" CreationDate="2016-03-19T09:28:01.357" Score="2" Body="&lt;p&gt;In addition to what @GordonStanger said, there are a few other points to consider.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Pollens and spores are made out of sporopollenin which &lt;a href=&quot;https://earthscience.stackexchange.com/a/409/87&quot;&gt;preserves way better than what one would expect&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Although there isn't probably a perfect 1-to-1 correspondance between pollen morphospecies and the plant species that produced them, there is still a wide variety of pollen morphospecies, and they still have usable first and last occurrences.&lt;/li&gt;&#xA;&lt;li&gt;But the main point is that pollen are produced by &lt;strong&gt;land&lt;/strong&gt; plants, meaning they have a continental origin. Yet, because some of them are transported by the wind or by water, you can still find them in marine sediments on top of finding them in terrestrial sediments, and this is a very valuable property: indeed marine sediments are easy to date precisely (thanks to magnetostratigraphy and the myriad of planktonic microfossil that sediment in them) while terrestrial sediments are really not (apart from pollen, small mammal remains can be used during the Cenozoic, but otherwise there really isn't any widespread biomarkers in terrestrial sediments, and geochronological dating is rarely possible). Pollen morphospecies first and last occurrences can thus be, in theory, dated with some accuracy thanks to marine sediments while being applicable to hard-to-date terrestrial sediments.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="87" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-03-19T09:28:01.357" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7712" PostTypeId="2" ParentId="7700" CreationDate="2016-03-20T18:10:20.370" Score="5" Body="&lt;p&gt;It can be problematic to use an earthquake magnitude scale for such purposes. To explain why, you have to look at the different scales how they were produced. The magnitude scales are normally used related to earthquakes on earth, resulting from elastic rebound effects from fault activity. The Richter scale (local magnitude, M&lt;sub&gt;L&lt;/sub&gt;) is, easily said, measured by the amplitude of a seismograph in &amp;lt; 100 km distance the centre. It gets inaccurate at a magnitude greater than 6.5. From a magnitude greater than ca. 8, even the teleseismic calculated surface-wave magnitude scale (M&lt;sub&gt;S&lt;/sub&gt;) gets inaccurate. For greater magnitudes, the magnitude has to be modelled in a completely different way: Here, the moment magnitude scale (M&lt;sub&gt;W&lt;/sub&gt;) is used. It is defined in relation to the seismic moment: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$M_{W} = \frac{2}{3} log (M_{0}) - 10.7 $&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The seismic moment M&lt;sub&gt;0&lt;/sub&gt; is defined as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$M_{0} = D *A * m$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$D$&lt;/span&gt; is mean displacement at the total fault, &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; is the fault and &lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt; the rigidity (shear strength) of the faulted rock. It can only be modelled by visible surface offset/displacement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, let's come back to the question: The magnitude of an earthquake is related to the length of the fault. The problem of a magnitude 13 is, that it is not possible according to this concept due to the earth's physical limitations. Keep in mind, that &lt;a href=&quot;https://earthscience.stackexchange.com/q/7266/5293&quot;&gt;with one magnitude higher, a quake has about 32 times more energy&lt;/a&gt;. Of course, you can compare the energy for instance to that of an impact event - which is also often done. However, it is not easy to presume the intensity.&lt;/p&gt;&#xA;" OwnerUserId="4784" LastEditorUserId="4784" LastEditDate="2018-12-19T16:19:16.640" LastActivityDate="2018-12-19T16:19:16.640" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="7713" PostTypeId="1" CreationDate="2016-03-20T19:36:34.297" Score="5" ViewCount="175" Body="&lt;p&gt;I need your help on a possible (but perhaps low probability) scenario for how the distance between Earth and the moon could change: say a large object from the Kuiper Belt manages to make its way into the inner system. It passes by our moon such that its gravity changes the moon's orbit around Earth into a more pronounced ellipse. So there will be times when the moon is much closer to Earth and other times when it's further away than its current distance from Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Say that this change in the moon's orbit isn't enough to cause an apocalyptic scenario for life on Earth but that the tides are of course much, much more pronounced. I surmise that the greatest impact would be felt in costal towns and cities around the world. My question is: how long would it take for the change in the moon's orbit to be felt on Earth? Are we talking almost immediately/ within the hour for some unlucky areas that are now much closer to the moon on its new orbit, and at most within 12 hours for the &quot;luckier&quot; areas? Or would the time frame be much longer?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you in advance for any insights you could offer on this.&lt;/p&gt;&#xA;" OwnerUserId="5660" LastActivityDate="2017-10-09T22:08:40.817" Title="If the distance between Earth and the moon were changed, would the effects be immediate?" Tags="|tides|" AnswerCount="1" CommentCount="1" ClosedDate="2017-10-10T15:39:25.913" ContentLicense="CC BY-SA 3.0" />
  <row Id="7714" PostTypeId="1" CreationDate="2016-03-21T00:50:19.783" Score="3" ViewCount="242" Body="&lt;p&gt;I am looking for hourly surface wind reanalysis data for the past two years. I am looking at the CFSR/CFSv2 data accessible from UCAR:&#xA;&lt;a href=&quot;http://rda.ucar.edu/datasets/ds094.1&quot; rel=&quot;nofollow&quot;&gt;http://rda.ucar.edu/datasets/ds094.1&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The 6-hourly products are &quot;complete&quot; (&lt;a href=&quot;http://rda.ucar.edu/datasets/ds093.0/&quot; rel=&quot;nofollow&quot;&gt;http://rda.ucar.edu/datasets/ds093.0/&lt;/a&gt;), while the hourly dataset (&lt;a href=&quot;http://rda.ucar.edu/datasets/ds094.1&quot; rel=&quot;nofollow&quot;&gt;http://rda.ucar.edu/datasets/ds094.1&lt;/a&gt;) is &quot;Selected&quot;. I take &quot;Selected&quot; to mean a subset of some kind. For those familiar with CFSR, what exactly is selected, and what is not contained in the dataset?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Suggestions on other sources of hourly reanalysis surface wind datasets would be appreciated as well.&lt;/p&gt;&#xA;" OwnerUserId="2645" LastActivityDate="2017-12-05T20:11:20.193" Title="CFSR hourly surface wind time series" Tags="|wind|open-data|reanalysis|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7715" PostTypeId="2" ParentId="7701" CreationDate="2016-03-21T04:30:24.863" Score="4" Body="&lt;p&gt;Europe is looking nicer and nicer every year (&lt;a href=&quot;http://www.nap.edu/read/13430/chapter/7#64&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/S2oh6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/S2oh6.jpg&quot; alt=&quot;Improvements in climate model resolution and process representation over time.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a little bit out of date, since AR5 is already out - the dates for the first 4 IPCC reports were:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;IPCC First Assessment Report, 1990&lt;/li&gt;&#xA;&lt;li&gt;IPCC Second Assessment Report, 1995&lt;/li&gt;&#xA;&lt;li&gt;IPCC Third Assessment Report, 2001&lt;/li&gt;&#xA;&lt;li&gt;IPCC Fourth Assessment Report, 2007&lt;/li&gt;&#xA;&lt;li&gt;IPCC Fifth Assessment Report, 2014&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;And an updated image for AR5 looks like this (both of these are AR5 model resolutions) (&lt;a href=&quot;http://www.climatechange2013.org/images/report/WG1AR5_Chapter01_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;, p145):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TVXkm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TVXkm.jpg&quot; alt=&quot;Improvements in modelling resolution in AR5&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And that same PDF has another representation of increasing complexity, where cylinder height indicates complexity (&lt;a href=&quot;http://www.climatechange2013.org/images/report/WG1AR5_Chapter01_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;, p144):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/q697m.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/q697m.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2016-03-21T04:30:24.863" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7716" PostTypeId="1" AcceptedAnswerId="7720" CreationDate="2016-03-21T15:46:19.923" Score="5" ViewCount="114" Body="&lt;p&gt;&lt;strong&gt;Q:&lt;/strong&gt; Which unit is attached to '&lt;em&gt;number of particles per volume&lt;/em&gt;' (e.g. of the atmosphere)? The questions focuses on the '&lt;strong&gt;number of&lt;/strong&gt;' and not on the 'volume'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The units [#/m&lt;sup&gt;3&lt;/sup&gt;], [particles/m&lt;sup&gt;3&lt;/sup&gt;] and [1/m&lt;sup&gt;3&lt;/sup&gt;] are used in publications. Neither [#/m&lt;sup&gt;3&lt;/sup&gt;] nor [particles/m&lt;sup&gt;3&lt;/sup&gt;] are SI compliant. However, [1/m&lt;sup&gt;3&lt;/sup&gt;] would be SI compliant but it looks ... incomplete.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;edit 1:&lt;/em&gt;&#xA;The particles are of different size and composition. Converting the number of particles into another unit is not reasonable for my application.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastEditorUserId="5594" LastEditDate="2016-03-21T16:20:59.230" LastActivityDate="2016-03-22T15:09:00.587" Title="How to write 'number of ...' in a unit?" Tags="|atmosphere|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="7717" PostTypeId="2" ParentId="7690" CreationDate="2016-03-21T16:52:09.520" Score="14" Body="&lt;p&gt;As you suggest, longer the path, larger the proportion of scattered radiation. Since the shorter wavelengths are more strongly affected by the Rayleigh scattering, sunlight appears more red when the sun is low.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lower solar elevation angle will also result in longer path through the ozone layer, and hence stronger absorption at the UV-B wavelength range. Together with the Rayleigh scattering, this will result in somewhat less UV-B compared to UV-A, all other things being equal. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://cprm.acom.ucar.edu/Models/TUV/Interactive_TUV/&quot; rel=&quot;noreferrer&quot;&gt;online version of NCAR's TUV radiative transfer model&lt;/a&gt; can evaluate the clear sky radiation for a given location and time. At noon, 45° north, I get UV-B/UV-A ratio of about 0.03 for 30th June and 0.01 for 30th January.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to the sun elevation, the radiative fluxes will be affected by a number of factors like clouds, surface albedo (snow!), aerosol extinction, and variations in the ozone layer.&lt;/p&gt;&#xA;" OwnerUserId="859" LastEditorUserId="725" LastEditDate="2017-01-28T01:02:14.830" LastActivityDate="2017-01-28T01:02:14.830" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7719" PostTypeId="1" CreationDate="2016-03-22T06:24:13.193" Score="5" ViewCount="621" Body="&lt;p&gt;Can we actually see an orange line of lava if we look down to the crack of the divergent boundary of tectonic plates?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="725" LastEditDate="2016-03-24T08:59:52.120" LastActivityDate="2016-03-25T03:35:27.877" Title="Can we see lava in a divergent tectonic boundary?" Tags="|geology|volcanology|plate-tectonics|petrology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7720" PostTypeId="2" ParentId="7716" CreationDate="2016-03-22T15:03:04.340" Score="7" Body="&lt;p&gt;In my experience $[m^{-3}]$ or $[cm^{-3}]$ as number density is very well understood throughout the communities of both earth, solar-system as well as exoplanetary scientists.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take for example the recently published &lt;a href=&quot;http://science.sciencemag.org/content/351/6279/aad8866.full&quot; rel=&quot;noreferrer&quot;&gt;The atmosphere of Pluto as observed by New Horizons&lt;/a&gt; which in fig. 3 shows the derived atmospheric composition of Pluto from occultation measurments in $[cm^{-3}]$ with some model curves:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Lms3B.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Lms3B.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; (Property of G. R. Gladstone et. al 2016 and the New Horizons Science team)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The density in this unit is just a very natural and convenient outcome of the used occultation-inversion techniques. Thus of course the units are sometimes simply the result of the context in which a work is done, and as other commentators stated, a mole could be used.&#xA;However I'd argue that $[cm^{-3}]$ is sufficiently simple to be understood in any context and adding moles just makes things unnecessary confusing as it suggests numbers to have a unit, which they don't.&lt;br&gt;&#xA;It just physically makes no sense.  &lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="489" LastEditDate="2016-03-22T15:09:00.587" LastActivityDate="2016-03-22T15:09:00.587" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7721" PostTypeId="2" ParentId="1073" CreationDate="2016-03-22T15:47:18.487" Score="2" Body="&lt;p&gt;Field geologists always carry a small squeeze bottle of dilute hydrochloric acid (HCl) to identify calcareous sedimentary rocks. One drop applied to the specimen is all you need and that amount will not damage your specimen. Muriatic acid is the same as HCl and is available at any hardware store and should be diluted in a 50/50 ratio with water.&lt;/p&gt;&#xA;" OwnerUserId="5665" LastActivityDate="2016-03-22T15:47:18.487" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7722" PostTypeId="1" AcceptedAnswerId="7723" CreationDate="2016-03-22T18:06:05.827" Score="9" ViewCount="1133" Body="&lt;p&gt;I can understand that the wavenumber is number of waves or cycles in a given distance. But what would a vertical wavenumber mean? Is it just another term for the wavenumber of a wave that is propagating vertically? I came across this in the context of oceanic internal waves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Precisely, how is it (if it is) different from the wavenumber of a wave in general?&lt;/p&gt;&#xA;" OwnerUserId="5084" LastEditorUserId="5084" LastEditDate="2016-03-22T18:14:20.083" LastActivityDate="2016-03-23T17:30:08.900" Title="What is a vertical wavenumber?" Tags="|oceanography|waves|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7723" PostTypeId="2" ParentId="7722" CreationDate="2016-03-22T19:51:25.463" Score="9" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0vLkb.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0vLkb.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the picture above we see an internal wave propagating in the direction of the wavenumber vector &#xA;$$\mathbf{K} = k \mathbf{e_x} + m \mathbf{e_z}$$&#xA;which (in 2D) is given by the vector sum of its components. $\mathbf{e_x}$ and $\mathbf{e_z}$ are unit vectors in the horizontal and vertical directions, respectively.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The continuity condition implies that $\mathbf{K} \cdot&#xA;\mathbf{u}=0$. Hence, the direction of&#xA;energy propagation (group velocity) is perpendicular to the direction of&#xA;propagation of wave crests and troughs (phase velocity). Internal gravity waves are transverse waves so the fluid motion is parallel to lines of&#xA;constant phase as indicated by the Eulerian velocity vector, $\mathbf{u}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The vertical wave number $m$ is the vertical component of the wavenumber vector because in a continuously stratified fluid internal waves can propagate in all directions. In fact, in the real ocean there is a third component, denoted by $l$ which is in the transverse direction so that the full wavenumber vector is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\mathbf{K} = k \mathbf{e_x} +  l \mathbf{e_y} + m \mathbf{e_z}$$&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2016-03-23T17:30:08.900" LastActivityDate="2016-03-23T17:30:08.900" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7725" PostTypeId="1" AcceptedAnswerId="7727" CreationDate="2016-03-23T10:58:35.110" Score="4" ViewCount="579" Body="&lt;p&gt;How does the gravitational anomaly measured at the Earth's surface and produced by a subsurface body depend on its depth and on the density contrast of the body relative to its surroundings?&lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="1379" LastEditDate="2016-03-29T00:24:46.430" LastActivityDate="2016-03-30T17:40:12.673" Title="Gravitational Anomaly of a subsurface body" Tags="|geophysics|geology|structural-geology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7726" PostTypeId="2" ParentId="7707" CreationDate="2016-03-23T15:16:57.507" Score="5" Body="&lt;p&gt;The mantle viscosity is likely to be non-linear, e.g., it could be as low as $10^{18} \textrm{Pa}\cdot\rm s$ (over shorter time scales) or as high as $10^{21} \textrm{Pa}\cdot\rm s$ (over longer time scales). In any case the values reported in the literature are somewhere between $10^{18}-10^{21} \textrm{Pa}\cdot\rm s$ and these are based on studies from earthquakes, glacial rebound etc. So you can calculate the relaxation time(s) using these two end member values. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;E.g., if you assume the average i.e., $10^{19.5} \textrm{Pa}\cdot\rm s$ then we get a relaxation time of $10^{19.5}/150\cdot10^9$ (viscosity/mu) which is $2.1082\cdot10^8$ seconds or ~$6.6$ years.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2016-05-25T13:38:59.707" LastActivityDate="2016-05-25T13:38:59.707" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7727" PostTypeId="2" ParentId="7725" CreationDate="2016-03-23T15:17:32.970" Score="3" Body="&lt;p&gt;The gravitational anomaly (delta_g) changes linearly with the density contrast, and proportionally to the inverse square of depth. That's simply a version of the 'Universal Law of Gravitation'.&#xA;Here is an example for the anomaly created by an spherical anomalous spherical body with a density difference of delta_rho relative to the surrounding density. &lt;em&gt;G&lt;/em&gt; is the known Gravitational Constant: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/U5qGi.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/U5qGi.png&quot; alt=&quot;From Turcotte and Schubert, 2002, Geodynamics&quot;&gt;&lt;/a&gt;&#xA;From Turcotte and Schubert, 2002, Geodynamics&lt;/p&gt;&#xA;" OwnerUserId="1379" LastEditorUserId="1379" LastEditDate="2016-03-30T17:40:12.673" LastActivityDate="2016-03-30T17:40:12.673" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7728" PostTypeId="2" ParentId="6515" CreationDate="2016-03-23T22:56:42.887" Score="2" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Northern_Hemisphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;Northern Hemisphere&lt;/a&gt; is 40% land and 60% water. The Southern Hemisphere is 20% land and 80% water.&lt;/p&gt;&#xA;" OwnerUserId="5671" LastEditorUserId="-1" LastEditDate="2017-07-04T10:48:38.090" LastActivityDate="2017-07-04T10:48:38.090" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7729" PostTypeId="2" ParentId="7707" CreationDate="2016-03-24T08:40:45.910" Score="5" Body="&lt;p&gt;The viscosity of the mantle varies largely with depth (because depth primarily controls temperature, pressure, and composition), but from the details of your question you seem particularly interested in the deformation time-response to large-scale changes in the stress distribution. The closest analogue to your imaginary scenario is the so called &lt;em&gt;post-glacial rebound&lt;/em&gt;, and a huge body of studies now show that the response time of topographic recovery after deglaciation is in the order of a &lt;strong&gt;few thousand years&lt;/strong&gt;. That's why Scandinavia is still uplifting today at rates of cm/yr, even if there is no ice sheet left there. The viscosities of the underlying fluid asthenosphere corresponding to such relaxation times are in the order of $10^{22} \textrm{Pa}\cdot\rm s$ to $10^{23} \textrm{Pa}\cdot\rm s$. These values result from adopting a layered model with constant viscosities, so it can give you an average value, or an effective value for your problem, but keep in mind that in reality the asthenosphere (upper mantle) properties are very heterogeneous. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Check f.e. Watts, 2002, page 115, &lt;a href=&quot;https://books.google.es/books?id=QlUgBqJ6m-MC&amp;amp;pg=PA115&amp;amp;lpg=PA115&amp;amp;dq=glacial+isostasy,+%22relaxation+time%22+viscosity+%22Pa%C2%B7s%22&amp;amp;source=bl&amp;amp;ots=KJLDSYQ48Z&amp;amp;sig=2Hx52W4MInTxEWt0uYVi1HpIYFg&amp;amp;hl=en&amp;amp;sa=X&amp;amp;redir_esc=y#v=onepage&amp;amp;q=glacial%20isostasy%2C%20%22relaxation%20time%22%20viscosity%20%22Pa%C2%B7s%22&amp;amp;f=false&quot; rel=&quot;nofollow&quot;&gt;https://books.google.es/books?id=QlUgBqJ6m-MC&amp;amp;pg=PA115&amp;amp;lpg=PA115&amp;amp;dq=glacial+isostasy,+%22relaxation+time%22+viscosity+%22Pa%C2%B7s%22&amp;amp;source=bl&amp;amp;ots=KJLDSYQ48Z&amp;amp;sig=2Hx52W4MInTxEWt0uYVi1HpIYFg&amp;amp;hl=en&amp;amp;sa=X&amp;amp;redir_esc=y#v=onepage&amp;amp;q=glacial%20isostasy%2C%20%22relaxation%20time%22%20viscosity%20%22Pa%C2%B7s%22&amp;amp;f=false&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the Earth is about 22 km wider at the equator than at the poles due to rotation, suppressing the centrifugal forces would imply a much larger effect than post-glacial rebound (1 order of magnitude larger). But the time-scales would be similar, since they are controlled by the asthenospheric viscosity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Remember that the asthenosphere is defined as the fluid (in geological time-scales) underlying the rigid lithosphere (the rigid plates). It is part of the upper mantle. &lt;/p&gt;&#xA;" OwnerUserId="1379" LastEditorUserId="1379" LastEditDate="2016-05-30T17:51:39.543" LastActivityDate="2016-05-30T17:51:39.543" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7730" PostTypeId="2" ParentId="7719" CreationDate="2016-03-24T08:59:20.307" Score="4" Body="&lt;p&gt;No, we can't. This is because of several reasons, mostly stemming from the fact that the plates are not diverging fast enough to keep the lava hot enough before it cools down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we go and look on diverging plate boundaries on land, such as on Iceland or East Africa, you don't have a &quot;line&quot; of lava. Instead, you have individual volcanoes located along a linear trend:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MJph4.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MJph4.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;source: &lt;a href=&quot;http://volcano.oregonstate.edu/vwdocs/volc_images/africa/africa.html&quot; rel=&quot;noreferrer&quot;&gt;http://volcano.oregonstate.edu/vwdocs/volc_images/africa/africa.html&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You see all the volcanoes along a line in the Ethiopia and Kenya region? It's not one &quot;line of lava&quot;, but single volcanoes along a line.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we think about divergent boundaries underwater, where the lava comes from a much shallower depth, we may think it might be possible to see this kind of feature. The problem is that water is extremely effective in cooling down lava. Here's an example video of what happens when there is lava underwater:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=hmMlspNoZMs&quot; rel=&quot;noreferrer&quot;&gt;https://www.youtube.com/watch?v=hmMlspNoZMs&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, the lava cools in seconds. It doesn't erupt fast enough to sustain a constant liquid lava &quot;line&quot; under water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is not something that happens on Earth. But on other planets, maybe. If we think of a planet where the surface temperatures are on the hundreds of degrees Celsius (such as Venus), the cooling of the lava may be slow enough for plate tectonics (if they exist on said planet) to catch up and provide enough magma to sustain a long-lived magma lake-river on the boundary.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-03-24T08:59:20.307" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7731" PostTypeId="1" CreationDate="2016-03-24T15:00:31.190" Score="6" ViewCount="1183" Body="&lt;p&gt;Wikipedia states the following about the P-Tr extinction event:&#xA;&quot;Because so much biodiversity was lost, the recovery of life on Earth took significantly longer than after any other extinction event,[5] &lt;strong&gt;possibly up to 10 million years.&lt;/strong&gt;[10]&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The source for the claim about 10 million years is this article: &lt;a href=&quot;https://www.sciencedaily.com/releases/2012/05/120527153810.htm&quot; rel=&quot;nofollow&quot;&gt;https://www.sciencedaily.com/releases/2012/05/120527153810.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another wiki article states:&#xA;&quot;Life on land took at least 30 million years to fully recover from the environmental disruptions which may have been caused by the eruption of the Siberian Traps.[10]&quot;&#xA;Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Siberian_Traps#cite_note-SahneyBenton2008RecoveryFromProfoundExtinction-10&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Siberian_Traps#cite_note-SahneyBenton2008RecoveryFromProfoundExtinction-10&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have a lot of questions about this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Frankly 10 million years sounds like a very short time to me in this context. Is it short or is it long?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;To expand the question:&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is the global ecosystem resilient to complete annihiliation? As long as there is some life left, is it likely to prevail? Let's say some catastrophe strikes and wipes out everything but bacteria - are we likely to see complex life ever again? I know there are debates about the Great Filter, but is there any consensus? What are the most popular contenders?&lt;/strong&gt; &lt;/p&gt;&#xA;" OwnerUserId="5426" LastEditorUserId="5273" LastEditDate="2016-03-27T08:10:44.460" LastActivityDate="2016-04-04T11:50:11.740" Title="How long does earth take to recover from mass extinctions? What is &quot;normal&quot;?" Tags="|paleoclimatology|paleontology|mass-extinction|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7732" PostTypeId="1" CreationDate="2016-03-24T15:43:07.957" Score="9" ViewCount="265" Body="&lt;p&gt;Sailplane, paraglider or hang-glider pilots are used to say &lt;em&gt;'thermal is released by trigger'&lt;/em&gt;.&lt;br/&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The zones with contrasting albedos (land/water, plowed field/forest) or locations where terrain profile changes abruptly are dubbed as triggers/release points. There are even legends about maneuvers of last hope when glider pilot dives down, makes a low pass above the overheated wheat field and thus releases thermal.&lt;br/&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is also a tendency to divide thermals behavior regarding the area - either it is a flatland or mountains - as if laws of nature were different.&lt;br/&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two things here which I do not like.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) The claims are not supported by or at least reference any scientific proof.&lt;br/&gt;&#xA;2) My own humble experience of thermal soaring partially contradicts with common beliefs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have many times witnessed long living dust devils. They are good examples of a non stationary point of detachment of hot air from the land surface. They actively move instead of being fixed to some special point like top of the heel.&#xA;Dust devils (not tornado) also can appear above water surface, so it looks like unstable layer of overheated air can magically ignore heat contrast between land and water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Large thermals also behave similarly...Well, at least some of them.&lt;br/&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In springs, when people burn old leaves, the smokes of fires converge and literally show you the point where thermal is. Being 1500 meters above the ground allows you to notice that the lowest part of the thermal moves quite noticeably even without background wind and do not stop where forest begins.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only practically useful book about thermals I have read so far is &lt;strong&gt;Scorer R. S. Environmental aerodynamics, Ellis Horwood Limitid Publisher Chichester. — N. Y., 1978.&lt;/strong&gt;&#xA;Though Scorer writes much about thermals structure (jets, plumes, thermals), he says almost nothing about how exactly unstable air is perturbed to give a birth to a thermal.&lt;/p&gt;&#xA;" OwnerUserId="5603" LastActivityDate="2016-07-27T09:13:58.637" Title="How are thermals really released?" Tags="|meteorology|mesoscale-meteorology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7733" PostTypeId="2" ParentId="7673" CreationDate="2016-03-24T19:27:43.843" Score="6" Body="&lt;p&gt;There is no inconsistency between the 2012 paper and the older reference(s).&lt;/p&gt;&#xA;&lt;p&gt;Fig. 2 arbitrarily sets all the components (x,y,z) of all the displacement vectors of all the centers to zero at the beginning of the time period (about 123,000 years ago).&lt;/p&gt;&#xA;&lt;p&gt;Furthermore the 2012 article states:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The horizontal movement of&#xA;topography associated with plate motion will then change the CF.&#xA;Over time, these slow phenomena can create large offsets, up to&#xA;&lt;strong&gt;hundreds of meters&lt;/strong&gt;, between CM and CF. When the evolution of&#xA;the internal load is reasonably inferred from other sources, then&#xA;these processes may be able to explain a significant bulk of the current&#xA;static offset between CM and CF.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://books.google.com/books?id=stFpBgAAQBAJ&amp;amp;pg=PA556&amp;amp;lpg=PA556&amp;amp;dq=distance%20CF%20and%20CM%20%22center%20of%20figure%22&amp;amp;source=bl&amp;amp;ots=4eTLab_1Dd&amp;amp;sig=Hj60t2cZXxtQivU9pA-bTbKApto&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwiwyqnI_9nLAhUBsIMKHbdOAFgQ6AEIKDAC#v=onepage&amp;amp;q=rcf&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;Planetary Sciences&lt;/a&gt;, table 1.2, says the distance between CF and CM is 0.80 km, citing to &lt;a href=&quot;https://books.google.com/books?id=aqjU_NHyre4C&amp;amp;pg=PA13&amp;amp;dq=yoder%20offset%20earth&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwiEqdOVidrLAhVIWh4KHYjoB80Q6AEIOzAE#v=onepage&amp;amp;q=figure%20offset&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;Yoder 1995&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;See also &lt;a href=&quot;http://link.springer.com/article/10.1007%2FBF00578814&quot; rel=&quot;nofollow noreferrer&quot;&gt;Evidence for convection in planetary interiors from first-order topography&lt;/a&gt; &lt;em&gt;The Moon&lt;/em&gt; March 1973, Volume 7, pages 172-180&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;It has been known for some time&#xA;that a center of mass-center of figure offset exists for the Earth (e.g. Jeffreys, 1962).&#xA;From a spherical harmonic analysis of the Earth's topography with the oceans replaced&#xA;by an equivalent mass of rock, Balmino et al. (1972) find the center of mass&#xA;displaced by 1.1 km from the center of figure in the direction 145°W long and 42 ° S lat.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;And from the NASA memorandum &lt;a href=&quot;https://books.google.com/books?id=xAscAn7HAAcC&amp;amp;q=%22For%20Earth,%20with%20its%20combination%20of%20sialic%22&amp;amp;dq=%22For%20Earth,%20with%20its%20combination%20of%20sialic%22&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwjb5pC6strLAhXBn4MKHatLBekQ6AEIKjAA&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reports of planetary geology program - 1981&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;For Earth, with its combination of sialic ([denisty]~2.7) and simatic ([density] 3.0-3.3) crusts, the CF is displaced toward 41.6°N, 34.7°E, in the direction of the Eurasian shield, and close to the center of the continental province at 46°N and 27°E (Bills and Ferrari, 1978).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;See also &lt;a href=&quot;https://grace.jpl.nasa.gov/data/get-data/geocenter/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geocenter - Degree 1&lt;/a&gt; :&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The spherical harmonic coefficients of degree 1 represent the distance between the center of mass of the Earth and its 'center of figure', which in practice is the center of a set of tracking stations on the surface of the Earth. Because of their physical meaning, time changes in degree 1 coefficients can be expressed in several equivalent forms (1) as distances in mm along the Z (along the axis of rotation), X and Y axes; (2) as (fully normalized) coefficients of the geopotential; (3) as the changes in mass (per unit area) that would give rise to the geopotential coefficients, expressed either in kg/m^2 or cm of equivalent water thickness.  The relation between these forms can be found in Swenson et al (2008), equations 5 and 4...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;And &lt;a href=&quot;https://books.google.com/books?id=3bQD1DJgliIC&amp;amp;pg=PA35&amp;amp;dq=below%20sea%20level,%20whereas%20the%20opposite%20hemisphere%20is%20dominated%20by%20the%202.5%20km%20time&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwiwr7qO2tvLAhXImR4KHVTmBjQQ6AEIHDAA#v=onepage&amp;amp;q=below%20sea%20level%2C%20whereas%20the%20opposite%20hemisphere%20is%20dominated%20by%20the%202.5%20km%20time&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;Planetary Surface Processes&lt;/a&gt; (2011):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In fact, the Earth itself has a substantial center of mass – center of figure offset if the water filling the ocean basins is neglected. The floor of the Pacific Ocean is about 5 km below sea level, whereas the opposite hemisphere is dominated by the continental ... The waterless Earth's center of figure is thus offset from its center of mass by about 2.5 km at the present time.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="248" LastEditorUserId="28693" LastEditDate="2023-03-16T14:10:11.387" LastActivityDate="2023-03-16T14:10:11.387" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="7735" PostTypeId="1" CreationDate="2016-03-24T20:26:25.007" Score="4" ViewCount="79" Body="&lt;p&gt;I'm writing a smart-watch watch-face app with weather details. Since it's on a 1&quot;x1&quot; screen, I'm trying to keep all information as compact as possible. I'm using open weather map for my testing, and have pulled wind speed and gust, but don't know if there's a standard way of formatting a composite value. Currently, I express the following information&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Direction: North&#xA;Speed: 8 (units per second is definable in user settings)&#xA;Gusts: 12 (defined in same units per second)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;as&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;N 8:12&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Which is not very descriptive and looks about like when I wake up. I'd like to use a meteorology standard if one exists. I'm pretty much limited to ascii unfortunately. Does such a standard way to present this information exist?&lt;/p&gt;&#xA;" OwnerUserId="5673" LastActivityDate="2016-03-24T21:50:16.553" Title="Is there a concise industry standard way of displaying wind speed, gust and direction?" Tags="|measurements|wind|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7736" PostTypeId="2" ParentId="7735" CreationDate="2016-03-24T21:13:58.047" Score="4" Body="&lt;p&gt;The colon could be problematic as its function is not directly clear in this context. Maybe you could try:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;N @ 8 m/s | G: 12 m/s&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;or a little shorter:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;N 8 (12) m/s&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The way you created it should not be problematic. However, especially if you make it possible for users to chose the unit, the unit should always be displayed. Here, the standard way in meteorology is to use meters per second [m/s], which is also complying to the SI units (more info &lt;a href=&quot;https://en.wikipedia.org/wiki/International_System_of_Units&quot; rel=&quot;nofollow&quot; title=&quot;here&quot;&gt;here&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The wind direction is often divided into two directional vectors, $u$ and $v$. However this is more science standard than industry standard as the ouput in degrees is more intuitive to interprete. In meteorology and climatology, the direction is only expressed in direction charcters (N, NE, E, ...) if the measurement or model output is not accurate enough to express it in directional degrees or if very exact values are not required, as for example in popular weather forecasts. (Notice that you can make it more exact by dividing the scale into smaller steps: Between N and NE, there is NNE, NEE, and so on).&lt;/p&gt;&#xA;" OwnerUserId="4784" LastEditorUserId="4784" LastEditDate="2016-03-24T21:50:16.553" LastActivityDate="2016-03-24T21:50:16.553" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7737" PostTypeId="1" CreationDate="2016-03-24T21:38:02.193" Score="5" ViewCount="672" Body="&lt;p&gt;Everyone is saying we are in a global warming, an unnatural one at that because of CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has there ever been a 'global warming' in Earth's history?  I know that global cooling is cyclical and 'looks' like global warming at the beginning of the cycle and luckily it is cyclical.  There was a good explanation that the 'great dying' was because of global warming.  If there is such a thing what would make global warming cyclical.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Venus is global warming for sure but what could have stopped the cycle of warming to go to cooler therms and stop the 'Venus' effect that can not be changed? There is a negative feedback for global cooling thus keeping that in check.  Is there a negative feedback for global warming?  &lt;/p&gt;&#xA;" OwnerUserId="606" LastEditorUserId="725" LastEditDate="2016-03-24T23:39:29.803" LastActivityDate="2016-04-15T20:26:38.117" Title="Global warming cycles" Tags="|atmosphere|climate-change|" AnswerCount="1" CommentCount="18" ContentLicense="CC BY-SA 3.0" />
  <row Id="7738" PostTypeId="2" ParentId="7698" CreationDate="2016-03-25T01:00:47.933" Score="2" Body="&lt;p&gt;Here is my  present approach.    &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;All &lt;strong&gt;wrfout-files&lt;/strong&gt; are located in the same path.&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Using &lt;strong&gt;pynco&lt;/strong&gt; in python loop to split the spin-up dataframe&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;import glob&#xA;nco = Nco()&#xA;for fn in glob.iglob('*.nc'):&#xA;    filename, extname = os.path.splitext(fn)&#xA;    output_fn = filename[11:22] + str(int(filename[22:24]) + 12) + extname&#xA;    nco.ncks(input=fn, output=output_fn, dimension='Time,13,')  &#xA;&lt;/code&gt;&lt;/pre&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The input shows like: &lt;code&gt;2014-04-04_12.nc&lt;/code&gt;(120 frame inside)&lt;br&gt;&#xA;The output shows like:&lt;code&gt;wrfout_2014-04-04_00:00:00.nc&lt;/code&gt;(133 frame inside)&lt;/p&gt;&#xA;" OwnerUserId="5214" LastActivityDate="2016-03-25T01:00:47.933" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7739" PostTypeId="2" ParentId="7719" CreationDate="2016-03-25T03:35:27.877" Score="2" Body="&lt;p&gt;What happens at a divergent boundary is that indeed the two sides are diverging along the entire length. However, this does not mean that there needs to be a crack (and indeed there isn't). Rather, lava pushes into the area from below but most of the time doesn't actually make it to the surface before it cools. This process is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Dike_(geology)&quot; rel=&quot;nofollow&quot;&gt;dyke intrusion&lt;/a&gt;, and the wikipedia page just linked to has some very good pictures. Because the spreading rate is pretty slow, it's also not necessary that dykes intrude the entire length of the boundary at the same time. Rather, they could introduce a part of the boundary this year, and some other part a couple of years later. If this just keeps happening, the intruding dykes will still push the two plates apart &lt;em&gt;on average&lt;/em&gt; over many years.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2016-03-25T03:35:27.877" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7740" PostTypeId="1" AcceptedAnswerId="7741" CreationDate="2016-03-25T08:42:37.850" Score="9" ViewCount="4565" Body="&lt;p&gt;The magnetic North (or South) Pole moves due to activities in the inner of Earth. And earthquakes can tilt the Earth's orientation a tiny bit. But can and does the axis' orientation relative to the surface change too? A major impact could surely do it, but could the Earth's inner activities?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;I don't mean precession, nor tectonics or continental drift, but the movement of the rotation axis. Could for example the geographic North Pole move to Greenland? (Not Greenland moving to the NP)&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="3033" LastEditorUserId="3033" LastEditDate="2016-03-25T10:19:03.463" LastActivityDate="2017-01-03T10:02:14.387" Title="Does the geographic North Pole move?" Tags="|earth-rotation|poles|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7741" PostTypeId="2" ParentId="7740" CreationDate="2016-03-25T11:16:22.493" Score="12" Body="&lt;p&gt;&lt;strong&gt;Yes, it's called &lt;a href=&quot;https://en.wikipedia.org/wiki/Polar_motion&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;polar motion&lt;/em&gt;&lt;/a&gt;.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rotational pole moves continuously, as you can see from the right-hand side of this figure (below) by the &lt;a href=&quot;http://hpiers.obspm.fr/eop-pc/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth Orientation Centre&lt;/a&gt; (EOC) and the &lt;a href=&quot;http://www.iers.org/IERS/EN/Organization/ProductCentres/EarthOrientationCentre/eoc.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;International Earth Rotation and Reference Systems Service&lt;/a&gt; (IERS). The figure shows about 650 days of time; &lt;code&gt;mjd&lt;/code&gt; is &lt;em&gt;modified Julian day&lt;/em&gt; and time goes along the locus in the polar motion diagram.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lP4kg.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lP4kg.png&quot; alt=&quot;The daily polar motion&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The left-hand side of the figure shows Length of Day, and I think that's chiefly why they are making these refined polar measurements — to keep track of leap seconds, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's been established, by Fong et al. (19996), among others, that &lt;a href=&quot;http://www.nasa.gov/topics/earth/features/japanquake/earth20110314.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;earthquakes could change the earth's rotational axis&lt;/a&gt;, by redistributing mass on a large scale. Their table 1 shows [the sort of effect that individual earthquakes theoretically have — &lt;em&gt;edited after comment from David Hammen&lt;/em&gt;] on the length of day; $\Psi$ is the excitation vector:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BsKx1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BsKx1.png&quot; alt=&quot;Table 1 from Fong et al 1996&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The EOC's website lists &lt;a href=&quot;http://hpiers.obspm.fr/eop-pc/index.php?index=excitation&amp;amp;lang=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;other geophysical excitations&lt;/a&gt;, among them:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Atmospheric angular momentum&lt;/li&gt;&#xA;&lt;li&gt;Oceanic angular momentum&lt;/li&gt;&#xA;&lt;li&gt;Hydrological excitation function&lt;/li&gt;&#xA;&lt;li&gt;Axial angular momentum of the core&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h3&gt;References&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Chao, Benjamin Fong, Richard S. Gross, Yan-Ben Han (1996). Seismic excitation of the polar motion, 1977–1993. &lt;em&gt;Pure and Applied Geophysics&lt;/em&gt;, September 1996, Volume 146, Issue 3, pp 407-419. &lt;a href=&quot;http://dx.doi.org/10.1007/BF00874727&quot; rel=&quot;nofollow noreferrer&quot;&gt;DOI 10.1007/BF00874727&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Update:&lt;/strong&gt; &lt;a href=&quot;http://www.nasa.gov/feature/nasa-study-solves-two-mysteries-about-wobbling-earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; on some new research in this field is worth a read.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2016-04-15T00:50:43.637" LastActivityDate="2016-04-15T00:50:43.637" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7742" PostTypeId="1" CreationDate="2016-03-25T22:17:02.870" Score="4" ViewCount="1008" Body="&lt;p&gt;I have read from Vlasenko et al. (2014) that the largest amplitude of an internal wave recorded in the Celtic Sea is 105 m. Is this the largest ever or have any larger ones been recorded elsewhere (eg. the Hawaiian mid-ocean ridge maybe)?&lt;/p&gt;&#xA;" OwnerUserId="5084" LastEditorUserId="111" LastEditDate="2016-03-26T12:40:48.630" LastActivityDate="2016-03-26T12:40:48.630" Title="What is the amplitude of the largest internal wave ever observed?" Tags="|ocean|oceanography|waves|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7743" PostTypeId="2" ParentId="7742" CreationDate="2016-03-26T04:35:59.897" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6xUe2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6xUe2.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I believe the largest internal waves ever recorded in the ocean were observed in the South China Sea (SCS). The diagram above is from &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/2010JPO4388.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Alford et. al (2010)&lt;/a&gt; - see the two ridges near A1 and N2? The gap between them is just the perfect size so that the barotropic tide can interact resonantly and give rise to very long internal tides which radiate away towards MP2 and eventually shoal (they also go the other direction but we ignore that since it's more or less the open ocean). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The internal tide is very long, but its amplitude is not that large. However, as the internal tide shoals it fissions into a train of solitary waves. The leading solitons in the wave train are larger in amplitude but smaller wavelength than the original internal tide that gave rise to them. Each soliton propagates at its own speed with the largest amplitude wave propagating faster. As the amplitude of each individual soliton grows, the fluid velocity will eventually exceed the wave speed and the waves will break due to convective instability (overturning). Thereby depositing their energy nearshore, far away from the generation zone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The largest amplitude wave measured in this study was around $200$~m, measured at LR2. But I am pretty sure I have seen other studies with larger amplitude waves in the SCS.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qhn6R.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qhn6R.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2016-03-26T04:42:20.447" LastActivityDate="2016-03-26T04:42:20.447" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7744" PostTypeId="1" CreationDate="2016-03-26T05:48:01.113" Score="1" ViewCount="69" Body="&lt;p&gt;My pond is fed by a spring that collects inside a large concrete box (6' x 6' x 8'deep) that was formed up many years ago.  The walls of this box are sitting on bedrock.  Small trickles of water seep through the bedrock when I clean the sand buildup out every ten years or so.  My question is, would drilling holes into the bedrock likely help or hurt the amount of water that is coming into the box? &lt;/p&gt;&#xA;" OwnerUserId="5678" LastActivityDate="2016-03-26T05:48:01.113" Title="Any way to increase the amount of water that flows through bedrock?" Tags="|hydrology|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7746" PostTypeId="1" AcceptedAnswerId="7747" CreationDate="2016-03-26T09:29:57.800" Score="4" ViewCount="4948" Body="&lt;p&gt;From WRF output file,     &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I find 3 variables related to the precipitation (unit: mm)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;1. Precipitation&lt;/strong&gt;    &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;variable name: pr     &lt;/li&gt;&#xA;&lt;li&gt;unit:$kg/(m^{2}s^1)$     &lt;/li&gt;&#xA;&lt;li&gt;variable: RAINC+RAINNC     &lt;/li&gt;&#xA;&lt;li&gt;comments: $dt(RAINC+RAINNC)/DT$&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;2. Max hourly precipitation rate&lt;/strong&gt;    &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;variable name: prhmax     &lt;/li&gt;&#xA;&lt;li&gt;unit:$kg/(m^{2}s^1)$     &lt;/li&gt;&#xA;&lt;li&gt;variable: RAINC, RAINNC or RAINMAX1Hclwrf   &lt;/li&gt;&#xA;&lt;li&gt;comments: $MAX(dtsum()/DT)$&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;3. Convective precipitation&lt;/strong&gt;    &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;variable name: prc     &lt;/li&gt;&#xA;&lt;li&gt;unit:$kg/(m^{2}s^1)$     &lt;/li&gt;&#xA;&lt;li&gt;variable: RAINC &lt;/li&gt;&#xA;&lt;li&gt;comments: $d_t(RAINC)/DT $       &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;My task:      &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Summarize the amount of days which precipitation &gt; 0.254 mm       &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What variable should I use for further analysis?   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any advice would be appreciated. &lt;/p&gt;&#xA;" OwnerUserId="5214" LastActivityDate="2016-03-26T11:01:46.433" Title="Calculate precipitation from WRF model output" Tags="|meteorology|atmosphere|atmosphere-modelling|wrf|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7747" PostTypeId="2" ParentId="7746" CreationDate="2016-03-26T11:01:46.433" Score="7" Body="&lt;p&gt;Use (1) Precipitation, as it is the sum of convective and non-convective precipitation, integrate it over one day, voilà.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;converting [$kg/(m^2 s)$] (precip):&#xA;$$ precip [kg/(m^2 s)] \cdot dt [s] \cdot \frac{1}{ \rho_w [kg/(m^3)]} \cdot 1000 [mm/m] = total\_precip [mm]$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\rho_w$ is the density of water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Practically the last two factors cancel.&lt;/p&gt;&#xA;" OwnerUserId="3419" LastActivityDate="2016-03-26T11:01:46.433" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7748" PostTypeId="1" AcceptedAnswerId="7751" CreationDate="2016-03-27T10:41:58.610" Score="16" ViewCount="1595" Body="&lt;p&gt;I was watching the science channel yesterday and the program mentioned the Great Pacific Garbage rim. I was struck by the illustration (and pretty much every subsequent animation/picture I've seen now has the same basic illustration) below:&lt;a href=&quot;https://i.stack.imgur.com/JuEln.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JuEln.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unless I'm not understanding something, the garbage swirls around in a huge  closed trajectory and encloses two sinks ( the colorful swirly things; one on the left and one on the right). This isn't physically possible though, with the perfectly reasonable assumption that the tidal force field is continuously differentiable. Any closed curve has to enclose equilibrium points who's indices add to $+1$, but a sink has an index of $+1$ so this curve encloses a total of $+2$. There would have to be at least one other equilibrium point inside the closed trajectory that had an index of $-1$, so something like a saddle node:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/n0agM.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/n0agM.gif&quot; alt=&quot;![enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I can't find any illustrations showing any other equilibrium points other than these two. Does anyone know what they are, or perhaps if I'm not understanding something?&lt;/p&gt;&#xA;" OwnerUserId="4674" LastEditorUserId="4674" LastEditDate="2016-03-27T10:48:09.000" LastActivityDate="2016-03-27T21:20:25.747" Title="Great Pacific Garbage Patch Equilibrium Points" Tags="|ocean|oceanography|models|ocean-currents|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7749" PostTypeId="2" ParentId="7748" CreationDate="2016-03-27T12:18:49.507" Score="18" Body="&lt;p&gt;Theoretically, I agree that there should be one instable equilibrium point between the two stable equilibrium points when we have a 2D current field. However, there are some additional components of the problem:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Ocean currents are not 2D but 3D currents. Considering only the sea surface might lets field lines disappear. &lt;/li&gt;&#xA;&lt;li&gt;The wind has an additional forcing. This is not true for all items and the wind already affects the ocean currents. However, litter items which are partly above the sea surface experience an additional wind forcing (see e.g. Yoon et al., 2010)&lt;/li&gt;&#xA;&lt;li&gt;Ocean currents are not time independent and equilibrium points may undergo a seasonal multi-annual cycling&lt;/li&gt;&#xA;&lt;li&gt;Accumulation zones are not necessarily stable equilibrium points but the residence time of the marine litter items in the named regions just needs to be sufficient long.&lt;/li&gt;&#xA;&lt;li&gt;The gyres are macroscopic accumulation regions. Thus, if we have regions with a higher density of particle trajectories and lower particles velocities we could identify these regions as accumulation regions from a macroscopic perspective. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;About item three (&lt;em&gt;Ocean currents are not time independent&lt;/em&gt;) I am not completely sure, but I think to remember an animation or plots in a publication which showed seasonal variations between the both garbage patches you showed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as I remember the publications on that topic of global transport modeling of marine litter correctly, the eastern North Pacific Garbage patch is the actual accumulation region. It has a long tail towards west. Howell et al. (2012) writes about the North Pacific Gyre and plastic debris accumulation within it. I did not have time to read it in detail.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For further reading it might be interesting to look into these publications:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Eriksen et al., 2014. doi: &lt;a href=&quot;http://dx.doi.org/10.1371/journal.pone.0111913&quot;&gt;10.1371/journal.pone.0111913&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Howell et al., 2012. doi: &lt;a href=&quot;http://dx.doi.org/10.1016/j.marpolbul.2011.04.034&quot;&gt;10.1016/j.marpolbul.2011.04.034&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Lebreton et al., 2012. doi: &lt;a href=&quot;http://dx.doi.org/10.1016/j.marpolbul.2011.10.027&quot;&gt;10.1016/j.marpolbul.2011.10.027&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Martinez et al., 2009. doi: &lt;a href=&quot;http://dx.doi.org/10.1016/j.marpolbul.2009.04.022&quot;&gt;10.1016/j.marpolbul.2009.04.022&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Maximenko et al., 2012. doi: &lt;a href=&quot;http://dx.doi.org/10.1016/j.marpolbul.2011.04.016&quot;&gt;10.1016/j.marpolbul.2011.04.016&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Yoon et al., 2010. doi: &lt;a href=&quot;http://dx.doi.org/10.1016/j.marpolbul.2009.09.033&quot;&gt;10.1016/j.marpolbul.2009.09.033&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2016-03-27T12:18:49.507" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7750" PostTypeId="2" ParentId="7698" CreationDate="2016-03-27T14:33:59.773" Score="2" Body="&lt;p&gt;There is an feature of the &lt;code&gt;-d&lt;/code&gt; option that makes the call of &lt;code&gt;ncks&lt;/code&gt; redundant. However, it is available since NCO version 4.2.1 (Aug. 2012).&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;ncrcat -d Time,13,,132,120 wrfout* summary.nc&#xA;# -d dim,[min][,[max][,[stride][,[subcycle]]]]&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;This feature is deeply hidden in the online manual. You find it here: &lt;a href=&quot;http://nco.sourceforge.net/nco.html#Subcycle&quot; rel=&quot;nofollow&quot;&gt;nco.sourceforge.net/nco.html#Subcycle&lt;/a&gt; .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Explanation:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;13: first time step we consider&lt;/li&gt;&#xA;&lt;li&gt;[empty]: till the end&lt;/li&gt;&#xA;&lt;li&gt;132: we have a cycle length of 132 steps&lt;/li&gt;&#xA;&lt;li&gt;120: we take the first 120 values (starting from the 13th) of each cycle&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;If we write &lt;code&gt;-d Time,13,0,132&lt;/code&gt;, which equals &lt;code&gt;-d Time,13,0,132,1&lt;/code&gt;, we would only get each 132nd value starting with the 13th.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do not process WRF output but we work with the Chemistry Transport Model CMAQ. We get hourly resolved concentration output files for each day. These files have 25 time steps (0 o'clock of the current and the next day) and we need to remove one of the ) o'clock time steps and append the files. For this purpose, I use &lt;code&gt;ncrcat -d TSTEP,0,,25,24 [infiles] [outfile]&lt;/code&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The straight forward approach would be to write a Fortran program for this purpose. But, I also prefer the NCO's. Maybe you could try the cdo's (&lt;a href=&quot;https://code.zmaw.de/projects/cdo&quot; rel=&quot;nofollow&quot;&gt;code.zmaw.de/projects/cdo&lt;/a&gt;) as an alternative. However, my solution with cdo's for this task was more bulky than the NCO solution.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2016-03-27T14:33:59.773" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="7751" PostTypeId="2" ParentId="7748" CreationDate="2016-03-27T16:02:00.867" Score="18" Body="&lt;p&gt;Yes, you're right, there should be (at least one) saddle point in the middle of the loop.  And indeed, if you search for illustrations of &lt;a href=&quot;https://www.google.fi/search?q=pacific+ocean+circulation&amp;amp;tbm=isch&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pacific ocean circulation&lt;/a&gt;, you can see the saddle point in some of them, like this one:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.goes-r.gov/users/comet/tropical/textbook_2nd_edition/navmenu.php_tab_4_page_3.1.0.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mJWLX.jpg&quot; alt=&quot;&quot;&gt;&lt;br&gt;&#xA;&lt;sup&gt;Source: &lt;em&gt;Introduction to Tropical Meteorology&lt;/em&gt;, 2nd ed., chapter 3.3.1, fig. 3.20.&lt;/sup&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, in a lot of other maps, the saddle region is just left more or less blank.  Apparently, that's because there just aren't any strong currents there; &lt;em&gt;most&lt;/em&gt; of the circulation is going in a loop around both sinks (and the saddle), with only a relatively small fraction diverted into the middle.  &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Ocean_currents_1943_%28borderless%293.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;This illustration from Wikipedia&lt;/a&gt; is a good example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Ocean_currents_1943_%28borderless%293.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/6/67/Ocean_currents_1943_(borderless)3.png/600px-Ocean_currents_1943_(borderless)3.png&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, unlike sinks, saddle points in general won't accumulate debris; any flotsam on the surface will just float in along the stable axis, and then away again along the unstable axis.  So even if there were strong surface currents in the region, you wouldn't expect any visible &quot;garbage patch&quot; there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Besides, at least if you look closely enough, reality will almost certainly be more complicated, with multiple equilibrium points that shift over time.  The following two maps (found on &lt;a href=&quot;https://www.lib.utexas.edu/maps/historical/pacific_islands_1943_1945.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this page&lt;/a&gt;), although fairly old and probably of limited accuracy, may show a hint of the true complexity:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sZ6GU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sZ6GU.jpg&quot; alt=&quot;Pacific ocean circulation in northern summer&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wRdfX.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wRdfX.jpg&quot; alt=&quot;Pacific ocean circulation in northern winter&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="142" LastEditorUserId="20" LastEditDate="2016-03-27T21:20:25.747" LastActivityDate="2016-03-27T21:20:25.747" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7752" PostTypeId="2" ParentId="7740" CreationDate="2016-03-27T21:27:13.607" Score="4" Body="&lt;p&gt;@kwinkunks already gave a good answer on the short time scale. On long time scales, mantle convection and plate tectonics redistributes large amounts of mass, and the conservation of angular momentum requires that the direction and speed or rotation of the Earth changes accordingly. (This is independent of the fact that the orientation of Earth's axis may stay put but continents may move over it, changing the &quot;apparent&quot; location of the poles.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Changing mass distribution because of mantle convection also indices torques on the Earth due to coupling with the rotation of the moon around Earth, and the Earth around the Sun. This, too, over time leads to changes of the Earth axis's direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both of these effects act on time scales of tens of millions of years.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2016-03-27T21:27:13.607" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7753" PostTypeId="1" CreationDate="2016-03-28T16:15:50.017" Score="4" ViewCount="332" Body="&lt;p&gt;What exactly is the difference between convergent precipitation and cyclone precipitation, their generation and characteristics?&lt;/p&gt;&#xA;" OwnerUserId="5692" LastActivityDate="2016-03-28T16:15:50.017" Title="Difference between convergent precipitation and cyclone precipitation?" Tags="|meteorology|climate|precipitation|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7754" PostTypeId="1" AcceptedAnswerId="7789" CreationDate="2016-03-28T17:46:42.883" Score="5" ViewCount="2320" Body="&lt;p&gt;I believe that the accepted theory for how Arizona's Grand Canyon was formed was that erosion caused by the Colorado River flowing through the area over millions of years was the force at work.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yet accounts of a massive flood have been passed down to various peoples throughout the world, even in landlocked areas. Could the Grand Canyon actually have been formed by such a cataclysmic flood?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In either case, it is assumed that vast amounts of water formed the gigantic chasm; the main difference being: over how much time did the transformation occur?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a global deluge were accepted as a possibility, is the condition and appearance of the Grand Canyon consistent with such an origin?&lt;/p&gt;&#xA;" OwnerUserId="3166" LastEditorUserId="725" LastEditDate="2016-03-29T04:48:50.000" LastActivityDate="2018-11-05T21:07:46.107" Title="Could a massive flood have formed the Grand Canyon?" Tags="|rivers|geomorphology|erosion|flooding|hydrogeology|" AnswerCount="3" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="7758" PostTypeId="2" ParentId="7754" CreationDate="2016-03-29T04:48:38.920" Score="14" Body="&lt;p&gt;tl;dr: &lt;strong&gt;no&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Long answer:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First of all, like mentioned by others in the comments, you would need some physical mechanism to take a whole lot of water, evaporate it, and drop it at once at a place where the Grand Canyon is now. This is not something that's going to happen because of physics. If there was some extraordinary event which could have caused this, we would get so much more evidence from it other than the Grand Canyon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But let's assume, that somehow, by some magic or act-of-higher-being, an enormously large amount of water fell on the Colorado plateau at once. How would that look?&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The huge amount rock removed from the plateau to form the canyon would have to go somewhere. And it would go there very violently, as huge boulders, irregular conglomerates and just a whole mess of mixed up geology. However, when you look downstream along the Colorado river, you don't see this stuff anywhere. When you look in the Gulf of California (which we know very well because of oil exploration), you don't see this stuff in there. Instead you see very nice sandstones, shales, marls, clays, etc. Definitely stuff that should not be there if there was a huge flood. Furthermore, those sedimentary rocks are interbedded with volcanic rocks and limestones. If this was a sudden event, all of this could not be there.&lt;/li&gt;&#xA;&lt;li&gt;The Colorado river is meandering. If it was a huge sudden flood you would not get this morphology.&lt;/li&gt;&#xA;&lt;li&gt;So far I was talking about lack of evidence. There is also some direct evidence for the incision rate of the Grand Canyon. Using a plethora of of scientific methods, such as radioactive isotope dating, cosmogenic dating, thermoluminescence, etc., it's possible to directly get a time when a certain thing happened (depending on the method). This allows us to know exactly when a certain rock formed, exposed, eroded (again, depending on the method). Using these scientific methods allowed us to infer that the Grand Canyon formed in the last several few million years, at an incision rate of a few dozen to a few hundred metres per one million year. The value depends on the exact location in the Grand Canyon and also on which research group you're asking. But whether the argument is about if it's 100 or 200 metres per million years is irrelevant for this discussion - it invalidates any suggestion that it formed in one sudden magical act of flood.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2016-12-30T02:16:02.800" LastActivityDate="2016-12-30T02:16:02.800" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7759" PostTypeId="2" ParentId="7732" CreationDate="2016-03-29T05:13:15.520" Score="2" Body="&lt;p&gt;I fly too, so I have first hand experience with movement of air below 13000 feet (Cessna 172). I have my simple version: in an otherwise calm weather a thermal has three stages which looked from profile looks like a tree. Base level near earth is the roots. Rising column is trunk. And cooling off and dissipating at high altitude is the canopy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The part that has lifting power most is column because it picks up speed and momentum while it spins and whirls like the water draining into a sinkhole. The rising column can be pushed and swivel around by wind or topology of area surrounding it. The source of energy is dark surface or topology or local climate that can create layered temperature gradient from hot near ground to cold at altitude. Of course as we pilots of small planes know there are many other factors involved specially in mountains. Fire fighters are keenly aware of the tunneling effect and unpredictability of thermal near the canyons. &lt;/p&gt;&#xA;" OwnerUserId="5697" LastEditorUserId="725" LastEditDate="2016-03-29T07:01:12.367" LastActivityDate="2016-03-29T07:01:12.367" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7760" PostTypeId="1" CreationDate="2016-03-29T06:52:05.450" Score="5" ViewCount="16420" Body="&lt;p&gt;What is the reason for having silicon in so large quantity on earth surface?&lt;/p&gt;&#xA;" OwnerUserId="2547" LastEditorUserId="725" LastEditDate="2016-03-29T09:00:30.803" LastActivityDate="2018-02-15T00:25:39.023" Title="Why silicon is abundant in earth surface?" Tags="|geology|geochemistry|earth-history|" AnswerCount="3" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="7761" PostTypeId="1" AcceptedAnswerId="7762" CreationDate="2016-03-29T07:58:33.137" Score="6" ViewCount="535" Body="&lt;p&gt;In atmospheric, the change of mixing ration $C_i$ of a chemical species $i$ is determined by:         &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\frac{\partial C_i }{\partial t} = -\bigtriangledown (VC_i)+\frac{\partial  }{\partial z}(k_z\frac{\partial C_i }{\partial z}) + (\frac{\partial C_i }{\partial z})_{dry}++ (\frac{\partial C_i }{\partial z})_{wet}+(\frac{\partial C_i }{\partial z})_{conv}+P_i-L_i+E_i$&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The first term represent the $Ci$ change due to horizontal and vertical advection.         &lt;/li&gt;&#xA;&lt;li&gt;The fifith term on the right hand represent the $Ci$ due to the vertical convection.   &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I have read about this question &lt;a href=&quot;https://physics.stackexchange.com/questions/24489/what-exactly-is-the-difference-between-advection-and-convection/118738#comment539944_118738&quot;&gt;&quot;What exactly is the difference between advection and convection?&quot;&lt;/a&gt;.        &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer told, which I quoted:   &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Advection is the movement of some material dissolved or suspended in the  fluid.&lt;br&gt;&#xA;  Convection is the movement of a fluid, typically in response to heat.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But when we are just talking about the chemical species. They are not in fluid form. So,how dos the convection process mean?       &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Update:  The equation was from a phD dissertatio &lt;em&gt;Climate and Air Pollution Modeling in South America focus on Megacities&lt;/em&gt;. Links &lt;a href=&quot;https://www.mpimet.mpg.de/fileadmin/publikationen/Reports/WEB_BzE_76.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;       &lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="-1" LastEditDate="2017-04-13T12:40:15.470" LastActivityDate="2016-03-30T01:04:25.067" Title="The difference of vertical advection and convection process for chemistry species" Tags="|meteorology|atmosphere|atmospheric-chemistry|air-quality|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7762" PostTypeId="2" ParentId="7761" CreationDate="2016-03-29T09:08:42.697" Score="6" Body="&lt;p&gt;The difference between advection and convection in Chemistry Transport models (CTMs) is a question of scale:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Advection&lt;/strong&gt; is driven by winds that are provided by the meteorological input dataset. Thus, the wind is resolved in the meteorological data.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Convection&lt;/strong&gt; is driven by sub grid processes (e.g. temperature gradients) and is paramterized in CTMs.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;See for example:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Pleim, 2007a. doi: &lt;a href=&quot;http://dx.doi.org/10.1175/JAM2539.1&quot;&gt;10.1175/JAM2539.1&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Pleim, 2007b. doi: &lt;a href=&quot;http://dx.doi.org/10.1175/JAM2534.1&quot;&gt;10.1175/JAM2534.1&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Rasch et al., 1997. doi: &lt;a href=&quot;http://dx.doi.org/10.1029/97JD02087&quot;&gt;10.1029/97JD02087&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2016-03-29T09:08:42.697" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7764" PostTypeId="2" ParentId="7760" CreationDate="2016-03-29T11:51:06.050" Score="1" Body="&lt;p&gt;The top 5 elements most abundant in the earth are: &lt;a href=&quot;https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth%27s_crust&quot; rel=&quot;nofollow&quot;&gt;Source with nice table wikipedia...&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Oxygen  &lt;/li&gt;&#xA;&lt;li&gt;Silicon   &lt;/li&gt;&#xA;&lt;li&gt;Aluminium &lt;/li&gt;&#xA;&lt;li&gt;Iron&lt;/li&gt;&#xA;&lt;li&gt;Calcium&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Silicon is a basic component in rock forming minerals: quartz, feldspar hornblende and other silicates. Silicon is common throughout the entire earth (probably less so in the core).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;All of the inner planets Mercury, Venus, Earth ( plus Moon) and Mars) appear to have silicon in abundance.  Rocky/stony meteorites also contain abundant silicon.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="1149" LastEditDate="2016-03-29T12:48:42.767" LastActivityDate="2016-03-29T12:48:42.767" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7765" PostTypeId="2" ParentId="7760" CreationDate="2016-03-29T12:16:32.287" Score="7" Body="&lt;p&gt;Silicon, in the form of silica (oxidised silicon: Si&lt;sup&gt;4+&lt;/sup&gt; or SiO&lt;sub&gt;2&lt;/sub&gt;), is indeed very common on Earth's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This answer has two parts: why is silicon common in the Earth as a whole, and why it is concentrated particularly in the crust (therefore the surface).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Why is silicon common in the Earth&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Silicon forms in nucleosynthesis processes in large stars (larger than our suns) and in supernovae. Turns out that quite a lot of silicon can be formed this way. When our solar system was still a hot molecular gas cloud, our region in place was rich in silicon (among other elements) so eventually Earth has lots of silicon in it. This is slightly beyond my field of expertise, so I will refer to the link daniel.neumann gave in his comment and to &lt;a href=&quot;http://scienceline.ucsb.edu/getkey.php?key=24&quot; rel=&quot;nofollow noreferrer&quot;&gt;this good explanation at UCSB Science Line&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Why is silicon extremely rich in the Earth's crust?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now we know there's quite a lot of silicon in the Earth to begin with. How do you end up with even more silicon in the crust (outermost layer) than in the mantle (middle layer, between the crust and the iron metallic core)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer lies in what happens to rocks when they melt. You have a rocky mantle, with let's say 35% to 45% of SiO&lt;sub&gt;2&lt;/sub&gt;. When this rock gets heated or decompressed (or wet, but nevermind this for now), it melts. But it doesn't melt completely, it melts only partially. This will always be richer in SiO&lt;sub&gt;2&lt;/sub&gt; than the original rock, and the residue of the melting now has even less SiO&lt;sub&gt;2&lt;/sub&gt;. Once SiO&lt;sub&gt;2&lt;/sub&gt;-rich melt moves upwards in the Earth (sometimes even erupting as volcanoes), it moves more SiO&lt;sub&gt;2&lt;/sub&gt;-rich material to the crust. Over billions of year and large successive partial melting events, you end up having quite a lot of SiO&lt;sub&gt;2&lt;/sub&gt; in the crust.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This gets even better, because in those SiO&lt;sub&gt;2&lt;/sub&gt;-rich rocks, you also have lots of quartz - which is a mineral composed of pure SiO&lt;sub&gt;2&lt;/sub&gt;: 100% SiO&lt;sub&gt;2&lt;/sub&gt;. This is a very resistant mineral to alteration and weathering. So if you have a granite that has only a third of quartz, with time the other two thirds (mostly feldspars) will decay and turn into clays (aka dust, mud). Only the quartz will be left behind, and the rest will wash away with water to the oceans (eventually). This is why you have impressive sand dunes which are &quot;seas&quot; of almost pure SiO&lt;sub&gt;2&lt;/sub&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oX6Bf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oX6Bf.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some other questions on this website you might be interested in:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/6893/725&quot;&gt;What was the likely composition of Earth&amp;#39;s early crust (how did crustal composition evolve)?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/174/725&quot;&gt;Why do felsic materials have lower melting points than mafic?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-03-29T12:16:32.287" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7766" PostTypeId="2" ParentId="2715" CreationDate="2016-03-29T17:08:55.300" Score="4" Body="&lt;p&gt;The two major sources of atmospheric nitrogen are volcanoes and bottom-dwelling denitrifying bacteria, who produce it from nitrate ion dissolved in seawater. If anyone knows the relative importance of these two sources, I'd very much appreciate knowing. Tx.&lt;/p&gt;&#xA;" OwnerUserId="5701" LastActivityDate="2016-03-29T17:08:55.300" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7767" PostTypeId="2" ParentId="7760" CreationDate="2016-03-29T18:05:27.363" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;What is the reason for having silicon in so large quantity on earth surface?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm assuming this is asking about the Earth's crust versus its mantle, rather than the crust versus the core, or the crust versus the universe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's lots of silicon in the mantle. Ordered by mass, the six most abundant elements in the mantle are oxygen, magnesium, silicon, iron, calcium and aluminum. These same six elements are also the most abundant elements in the crust, but with a different ordering. Ranked by mass, the six most abundant elements in the crust are oxygen, silicon, aluminum, iron, calcium, and magnesium. The singular most marked difference between mantle rock and crustal rock is magnesium. It's not so much that the crust is enriched with silicon as it is that the crust is strongly depleted of magnesium compared to the mantle. Magnesium is the only common lithophilic element that displays this behavior.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason is the partial melt that occurs where volcanoes and magmatic intrusions form. The chemical nature of magnesium tends to makes magnesium compounds stay with the solidus. This in turn differentiates the crust from the mantle.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2016-03-29T22:56:12.303" LastActivityDate="2016-03-29T22:56:12.303" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7768" PostTypeId="1" CreationDate="2016-03-31T02:14:51.380" Score="1" ViewCount="78" Body="&lt;p&gt;I was at an academic conference recently and one of the presenters mentioned examining certain variables before and after the top 21 climate change meetings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately I was not able to get a hold of her after the conference and I have no background in earth science/climate change. Does anyone know what she could have been referring to?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am aware of the COP and CMP only held by the UN.&lt;/p&gt;&#xA;" OwnerUserId="5705" LastEditorUserId="20" LastEditDate="2016-04-01T00:26:53.003" LastActivityDate="2016-04-01T00:26:53.003" Title="What are the top 21 meetings regarding climate change?" Tags="|climate-change|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7769" PostTypeId="1" CreationDate="2016-03-31T04:26:17.560" Score="-1" ViewCount="116" Body="&lt;p&gt;Recently my prof asked a question:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Why in subequatorial regions do we have six months of rainy season and six months dry season?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;How do wet and dry seasons 'form'? I can't find the answer anywhere on the net. Can anyone help with the answer?&lt;/p&gt;&#xA;" OwnerUserId="5706" LastEditorUserId="595" LastEditDate="2016-03-31T09:42:14.283" LastActivityDate="2016-03-31T09:52:22.770" Title="Climate in subequatorial regions" Tags="|climate|seasons|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7770" PostTypeId="1" AcceptedAnswerId="7773" CreationDate="2016-03-31T06:30:44.813" Score="4" ViewCount="393" Body="&lt;p&gt;I know persistent lava lakes are rare, but do they occur in all volcanoes &lt;em&gt;originally&lt;/em&gt;, and just not persist over time?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="595" LastEditDate="2016-03-31T09:42:22.783" LastActivityDate="2016-04-04T19:19:00.113" Title="Do lava lakes exist in all volcanoes initially?" Tags="|volcanology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7772" PostTypeId="2" ParentId="7769" CreationDate="2016-03-31T07:52:50.730" Score="1" Body="&lt;p&gt;You should read about the intertropical convergence zone and its seasonal movements. Here you will find all the answers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Intertropical_Convergence_Zone&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Intertropical_Convergence_Zone&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ITCZ follows the sun as the convergence happens where most of the radiation comes in. As the ITCZ has finite depth it means that some regions are only under its influence when it is at its northernmost or southernmost location, and these are the regions your professor mentioned.&lt;/p&gt;&#xA;" OwnerUserId="5689" LastEditorUserId="5689" LastEditDate="2016-03-31T09:52:22.770" LastActivityDate="2016-03-31T09:52:22.770" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7773" PostTypeId="2" ParentId="7770" CreationDate="2016-03-31T10:07:01.943" Score="6" Body="&lt;p&gt;No, they do not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lava lakes require the lava to have low viscosity (that is, be very fluid or water like). If you look at the Wikipedia article for Lava lake, you will see that &quot;basalt&quot; or &quot;phonolite&quot; are mentioned. Those are indeed types of lavas (actually rock) that are very fluid. These are the kind of lava that end up forming lava flows.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, there are other types of lavas that do not flow, because their viscosity is too high: rhyolite is one example. Explosive volcanoes (think Mt St Helens) are explosive (mostly) because of the high viscosity of the lava. Therefore, volcanoes erupting explosively (almost) never have lava lakes, because the lava itself is not fluid enough to make a lake.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2016-03-31T21:24:57.277" LastActivityDate="2016-03-31T21:24:57.277" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7774" PostTypeId="2" ParentId="7768" CreationDate="2016-03-31T12:02:50.030" Score="3" Body="&lt;p&gt;As Isopcycnal Oscillation has noted in the comments, you've probably misheard, and what they were talking about was &lt;a href=&quot;http://www.cop21paris.org/about/cop21&quot; rel=&quot;nofollow&quot;&gt;COP 21&lt;/a&gt; (not &quot;top 21&quot;), the 21&lt;sup&gt;st&lt;/sup&gt; summit of the &lt;a href=&quot;http://newsroom.unfccc.int/&quot; rel=&quot;nofollow&quot;&gt;UNFCCC&lt;/a&gt; parties in Paris, December 2016.&lt;/p&gt;&#xA;" OwnerUserId="100" LastActivityDate="2016-03-31T12:02:50.030" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7777" PostTypeId="2" ParentId="7661" CreationDate="2016-03-31T16:42:52.787" Score="1" Body="&lt;p&gt;An excellent explaination found here: &lt;a href=&quot;https://www.youtube.com/watch?v=ZD1roP5wISU&quot; rel=&quot;nofollow&quot;&gt;https://www.youtube.com/watch?v=ZD1roP5wISU&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Goes into detail about Rayleigh dispersion.&lt;/p&gt;&#xA;" OwnerUserId="5615" LastActivityDate="2016-03-31T16:42:52.787" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7779" PostTypeId="1" CreationDate="2016-04-01T04:00:02.040" Score="1" ViewCount="633" Body="&lt;p&gt;I'm calculating the inclusive graphic standard deviation for sediment from a cumulative frequency graph, with this formula:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kIyobm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kIyobm.png&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But when I plug in the numbers, I get a negative value, because my ranges at 5, 16, 84 and 95 span the 0φ boundary. What does this mean? Does this mean it is very well sorted, or have I made a calculation error?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My data:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4OdKc.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4OdKc.png&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5711" LastActivityDate="2016-09-04T22:34:07.050" Title="What does a negative value for the inclusive graphic standard deviation mean?" Tags="|geology|rocks|sedimentology|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7781" PostTypeId="1" AcceptedAnswerId="7782" CreationDate="2016-04-01T08:35:44.797" Score="3" ViewCount="6504" Body="&lt;p&gt;How are atmospheric layers named once they have been discovered?&lt;/p&gt;&#xA;" OwnerUserId="5712" LastEditorUserId="87" LastEditDate="2016-04-01T08:40:26.353" LastActivityDate="2016-04-01T15:13:17.807" Title="How did Earth's atmospheric layers get their names?" Tags="|atmosphere|history-of-science|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7782" PostTypeId="2" ParentId="7781" CreationDate="2016-04-01T15:13:17.807" Score="8" Body="&lt;h1&gt;Who gave the names Troposphere and Stratosphere&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The stratosphere was firstly discovered by Léon-Philippe Teisserenc de Bort and Richard Aßmann (they did not cooperate) around 1900. Teisserenc de Bort denoted that layer as 'zone isotherme' in his publication on his discovery. However, he published in French. I remember to have read somewhere - not sure where - that he gave the two names 'troposphere' and 'stratosphere' to the two lower layers after discovering the existence of a quite distinct second layer. Unfortunately, I do not find the reference anymore. In the article &lt;a href=&quot;http://empslocal.ex.ac.uk/people/staff/gv219/classics.d/Hoinka-tropo97.pdf&quot;&gt;Hoinka (1997)&lt;/a&gt; you will find some information about the discovery of the stratosphere.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;What the Names mean&lt;/h1&gt;&#xA;&#xA;&lt;h2&gt;Troposphere&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;tropos (greek): turn(ing)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Turbulent mixing is relevant in this layer of the atmosphere =&gt; Turbulent Mixing Sphere =&gt; Troposphere&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Stratosphere&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;stratum (latin): something which covers something else (pavement, blanket)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This layer of the atmosphere, which is not dominated by turbulent mixing, covers the lower turbulent layer =&gt; Covering Sphere =&gt; Stratosphere&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Mesosphere&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;mesos (greek): middle&#xA;This part of the atmosphere is the third of five (from humans defined) layers of the atmosphere =&gt; Layer in the middle (not by distance/height but by counting layers) =&gt; Mesosphere&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Thermosphere&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;thermos (greek): warm, heat&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This layer can be heated to above 1000 °C by the sun. However, it does not feel 'warm' because of the low 'air' density. =&gt; Heated/hot layer =&gt; Thermosphere &lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Exosphere&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;éxo (greek): outside, external&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This layer is the most outward located layer of the atmosphere. =&gt; At the outer side located =&gt; Exosphere&lt;/p&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2016-04-01T15:13:17.807" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7783" PostTypeId="1" CreationDate="2016-04-02T04:06:11.393" Score="2" ViewCount="258" Body="&lt;p&gt;PBL is one key physical quantities aimed at analysing the condition of air pollution in an area of interest.&lt;br&gt;&#xA;From WRF simulation, I can get the variable &lt;strong&gt;&lt;code&gt;PBLH&lt;/code&gt;&lt;/strong&gt; whixh represents the PBL height.&lt;br&gt;&#xA;But, is there any free data source offering the &lt;strong&gt;&lt;code&gt;observing PBL height&lt;/code&gt;&lt;/strong&gt; all over the World?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For now, I can get the weather data from the NOAA weather center. The data based on observations at airports doesn't conclude the quantitative information of PBL.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any recommendation would be appreciate! &lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="2470" LastEditDate="2016-04-02T12:47:24.117" LastActivityDate="2016-04-06T08:20:35.227" Title="Data source of the planetary boundary layer (PBL)" Tags="|meteorology|atmosphere|atmosphere-modelling|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="7784" PostTypeId="1" CreationDate="2016-04-02T20:29:56.727" Score="2" ViewCount="157" Body="&lt;p&gt;Let me try to clarify what I'm really asking: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Imagine that, for whatever reason, the meteorologists and Earth scientists decide to revisit the definitions of the seasons---to define them from scratch based on the current best science (kind of like what the astronomers were forced to do as far as &lt;a href=&quot;https://en.wikipedia.org/wiki/IAU_definition_of_planet&quot; rel=&quot;nofollow&quot;&gt;the definition of a planet&lt;/a&gt;). Based on our current best science, would it make sense to identify the winter/spring boundary as the date of final stratospheric warming? Or are there other considerations that are arguably more important---that arguably make more scientific sense as winter/spring demarcators?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is not about the history of the concept of the seasons, or about linguistics. I of course realize that the concept of final warming has been discovered only relatively recently, while the concept of the seasons has been around for millennia. I'm asking about &lt;strong&gt;scientific definitions&lt;/strong&gt; here, which can and do change as science advances (e.g. Pluto used to be classified as a planet, and now it's not). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Not that it matters for my question, but: if the science started saying that this is the new definition, the media would start reporting it, and eventually even the public at large would become aware of it. Speaking of which---and yes, sorry, this is off topic---but does anyone have any guesses as to why &lt;em&gt;don't&lt;/em&gt; the major media outlets report on the date of the polar vortex breakup, regardless of the definition of the seasons? After all, the public is now quite aware of the polar vortex, given it has been blamed for so many cold spells recently.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Background&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the Wikipedia article 'Sudden stratospheric warming',&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The radiative cycle in the stratosphere means that during winter the&#xA;  mean flow is westerly and during summer it is easterly (westward). A&#xA;  final warming occurs on this transition, so that the polar vortex&#xA;  winds change direction for the warming, however do not change back&#xA;  until the following winter. This is because the stratosphere has&#xA;  entered the summer easterly phase. It is final because another warming&#xA;  cannot occur over the summer, so it is the final warming of the&#xA;  current winter.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Similarly, a &lt;a href=&quot;http://ozonewatch.gsfc.nasa.gov/facts/warming_NH.html&quot; rel=&quot;nofollow&quot;&gt;NASA-affiliated source&lt;/a&gt; says that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The final warming is the last stratospheric warming of the season.&#xA;  After this warming, the stratosphere never recovers to its previous&#xA;  state and the vortex breaks up and dissipates. The final warming often&#xA;  occurs in March or April. Sometimes the stratosphere never recovers&#xA;  from what would otherwise be a mid-winter major warming in January or&#xA;  February, and that warming becomes the final warming.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As far as I understand it, once the polar vortex breaks up, one cannot have sudden large temperature dips (like we are having in the northeastern part of the US &lt;a href=&quot;http://nymag.com/daily/intelligencer/2016/03/polar-vortex-is-visiting-nyc-this-weekend.html&quot; rel=&quot;nofollow&quot;&gt;this weekend of April 2-3, 2016&lt;/a&gt;). Thus it would seem that the date of final warming is a good candidate for the official date of the end of &quot;meteorological winter&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, NOAA defines seasons according to calendar months (see &lt;a href=&quot;http://www.ncdc.noaa.gov/news/meteorological-versus-astronomical-summer%E2%80%94what%E2%80%99s-difference&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;). Meanwhile, the Swedes define the start of spring as &quot;when the average daytime temperature exceeds zero degrees Celsius on seven consecutive days&quot; (see &lt;a href=&quot;http://www.thelocal.se/20090313/18200&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So: purely on the basis of current best science, would it make sense to define the end of winter as the date of the final warming? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, one could not know that it happened until some time after it happened, but my understanding is that this lag is on the order of days, not weeks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, such a definition would have the consequence that some years, meteorological winter would end in January. But, so what? Some winters do seem to end in January... while the present one lasts into April.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, one cannot define the demarcation between the spring and summer or summer and fall using the polar vortex as a reference. But, so what? There is no reason why each demarcation couldn't be a separate story. Even the fall/winter boundary need not necessarily be defined as the date of the formation of the polar vortex.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(And while we're at it--and I know this is off topic, but still---why don't the media report the date of the breakup of the polar vortex? It seems it would be of interest to people, given the notoriety the concept has received especially the last couple of winters... In fact, is the date reported anywhere?)&lt;/p&gt;&#xA;" OwnerUserId="5724" LastEditorUserId="5724" LastEditDate="2016-04-04T00:04:31.663" LastActivityDate="2016-04-04T00:04:31.663" Title="Why isn't the date of final stratospheric warming and polar vortex breakup regared as the official end of winter?" Tags="|seasons|" AnswerCount="0" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="7785" PostTypeId="2" ParentId="7731" CreationDate="2016-04-04T11:23:14.413" Score="3" Body="&lt;p&gt;Mass extinctions are selective: not all living organisms will be affected by it to the same extent. Meaning also that various groups will recover from it at various speed: a group from which half of the species were exterminated by the event will most probably take longer to recover (i. e. reach its pre-event diversity) than a group for which only 10% of the species are gone. And a group for which 95% of the diversity is gone is likely to never fully recover its initial diversity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are looking at the recovery of the ecosystem/biome as a whole, then what is likely to happen is that the extinct species left whole ecological niches vacant, meaning that this vacuum is likely to be quickly filled by new species (either species group that already existed and were already occupying this ecospace but were dominated by the now-extinct species or brand new species group). On that subject, one has to realise also that the recovery of a trophic level of an ecosystem is dependent on the recovery of the others (i. e. and to simplify, recovery of apex predators depends of the recovery of grazers, which depends on the recovery of primary producers etc.), so a mass extinction affecting primarily the primary producers might need longer to recover than one affecting mainly the apex predators.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So is 10 Myr a short amount of time to recover from a mass extinction? I'll say that one would expect ecological recovery to be faster than that (see for instance the speed at which milieux disturbed by glacial episodes recover during interglacials, or the speed at which new islands get colonised). But for the complete recovery of global diversity (in particular for an event supposedly wiping out 90% of life diversity) i'd have expected it to take longer than 10 Myr. &lt;a href=&quot;http://rspb.royalsocietypublishing.org/content/royprsb/275/1636/759.full.pdf&quot; rel=&quot;nofollow&quot;&gt;In the second article you link&lt;/a&gt;, the authors estimate that the recovery of the terrestrial ecosystem is fast by comparison with how long it took to colonise the land in the first place (i. e. 100 Myrs). But all the evolutionary adaptations needed to function on land do not need to be re-evolved, so it seems rational to expect it to take a shorter time than those 100 Myrs... Otherwise the probable reason the news article you linked considered it to be a long recovery time was to emphasise the fact that the &lt;a href=&quot;http://dx.doi.org/10.1038/ngeo1475&quot; rel=&quot;nofollow&quot;&gt;article&lt;/a&gt; show that it took longer because of ripple effects of the Permo-Triassic event during the early Triassic that slowed down the recovery.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a review of mass extinction recovery predating those two articles, &lt;a href=&quot;http://dx.doi.org/10.1016/S0169-5347(98)01436-0&quot; rel=&quot;nofollow&quot;&gt;Erwin (1998)&lt;/a&gt; estimated the duration of the recovery from the End Ordovician, Frasian-Fammenian, end-Permian, end-Triassic and K/T extinction events (I mention here only the so-called &quot;Big Five&quot; extinctions) to, respectively, 7, 3, &quot;3 to 9?&quot;, 3 and 2 millions years. With those number in mind, then indeed 10 Myrs is a long recovery.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same article also had this to say about the definition of mass extinction recovery:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How does one define a recovery? Mass extinctions create new ecological opportunities, and the common-sense definition of a recovery interval encompasses the rapid diversification by surviving lineages following the end of the extinction and ending with either the waning of the rapid, postextinction diversification or the return of normally functioning communities. Normal is hard to quantify, however, even without the extensive disruptions associated with some mass extinctions. Moreover, different clades recover at different rates and the same clade can recover at different rates in different regions. If we accept the recovery as beginning with an increase in evolutionary rates, this usefully distinguishes an immediate, postextinction survival interval, dominated by surviving lineages, from the often exuberant diversifications of the subsequent recovery phase. An alternative definition relies on the 're-establishment of pre-extinction isotopic values and ecosystems that are essentially equivalent to those that existed before the extinction'. Here the emphasis lies equally on the physical environment and the ecosystem recovery.&lt;br&gt;&#xA;  &lt;sub&gt;Douglas H. Erwing, 1998. &lt;a href=&quot;http://dx.doi.org/10.1016/S0169-5347(98)01436-0&quot; rel=&quot;nofollow&quot;&gt;The end and the beginning:&#xA;  recoveries from mass extinctions&lt;/a&gt;, &lt;em&gt;Trends in Evolution and Ecology&lt;/em&gt;.&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Finally, evolution is non-repeatable: so to answer your question &quot;Let's say some catastrophe strikes and wipes out everything but bacteria - are we likely to see complex life ever again&quot;, the answer is that if all eukaryotes are wiped out then no eukaryotes is likely to reappear, but another &quot;complex&quot; group can appear anew (though bacteria are already very complex if you ask me). Similarly if life is completely wiped out I don't think it is reasonable to think it will reappear (in particular because the Hadean/Archean conditions that saw its appearance do not exist anymore).&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2016-04-04T11:50:11.740" LastActivityDate="2016-04-04T11:50:11.740" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7786" PostTypeId="1" AcceptedAnswerId="7787" CreationDate="2016-04-04T13:25:40.103" Score="13" ViewCount="3909" Body="&lt;p&gt;This question arose from &lt;a href=&quot;https://physics.stackexchange.com/questions/46304/how-is-it-possible-for-an-ultrasound-device-to-correctly-interpret-a-negative-de&quot;&gt;a related one&lt;/a&gt; at Physics.SE, along with my own personal quest to better understand mineralogical prospecting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to know if some kind of ultrasound machine can determine the density of rock, soil, or mountains. Could it see everything within range? For example, could it see a region of high density and a region of low density behind it? Or would one block the other? What would the range be?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And how accurate would it be (in density readings and exact location readings)? More accurate than a gravimetric map?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm asking because I want to know if ultrasounds can be used for mineralogic prospecting (exploring for ores that can be mined). It seems like it would be a lot easier to use ultrasounds than to dig a lot of exploratory shafts.&lt;/p&gt;&#xA;" OwnerUserId="2733" LastEditorUserId="2470" LastEditDate="2021-08-28T10:32:15.057" LastActivityDate="2021-08-28T10:32:15.057" Title="Can ultrasounds be used to map the density of large underground regions?" Tags="|geology|geophysics|mineralogy|mining|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7787" PostTypeId="2" ParentId="7786" CreationDate="2016-04-04T14:14:57.770" Score="19" Body="&lt;p&gt;&lt;strong&gt;Sound-like waves are routinely used to image the subsurface, but mostly well below the ultra-sound band.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Several methods involve sound-like vibrations:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Reflection_seismology&quot; rel=&quot;noreferrer&quot;&gt;Reflection seismic&lt;/a&gt; — the most important subsurface remote sensing tool we have&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Seismic_refraction&quot; rel=&quot;noreferrer&quot;&gt;Refraction seismic&lt;/a&gt; — important, but niche, and has a lot in common with reflection&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Sonic_logging&quot; rel=&quot;noreferrer&quot;&gt;Acoustic logging&lt;/a&gt; — uses ultrasound, which you specifically asked about&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h3&gt;What do you mean, 'sound-like'?&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;I say 'sound-like', because we normally think of sound as a vibration that we can hear, conducted through air or maybe water or building materials. In seismic methods — such as we might use prospecting for minerals, oil and gas, water, geothermal resources, etc. — we use very low frequencies, typically in the 4–256 Hz range (about 6 octaves). You can certainly hear some of these frequencies, but not those below about 20 Hz, which are often the strongest frequencies in our signal.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Why is seismic reflection such a big deal?&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;From thousands of field recordings, usually shot in a grid over a land or marine area, we can reconstruct an image of the subsurface using a process called &lt;a href=&quot;https://en.wikipedia.org/wiki/Seismic_tomography&quot; rel=&quot;noreferrer&quot;&gt;tomography&lt;/a&gt;. The data might be 2D (a vertical cross-section) or 3D (a volume, analogous to a CAT scan). In some cases, this image is excellent and reveals a great deal about the geology of the region. Here's an example from a paper by &lt;a href=&quot;http://science.sciencemag.org/content/318/5853/1128.full&quot; rel=&quot;noreferrer&quot;&gt;Moore et al. (&lt;em&gt;Science&lt;/em&gt;, November 2007)&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QORWq.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QORWq.jpg&quot; alt=&quot;Moore et al seismic image&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;How much can you see?&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;A large survey might be hundreds of square kilometres, or many tens of kilometres long in the case of 2D data. We can image &lt;em&gt;well&lt;/em&gt; down to about 6–8 km, and we can image &lt;em&gt;something&lt;/em&gt; down to about 20 km. The typical resolution of seismic is on the order of tens of metres horizontally and a few metres vertically (about a quarter of a wavelength). This is much better than gravity or magnetics. You might think, &quot;Why not use higher frequencies for imaging — surely you'd see more?&quot; Yes! We would love to use ultrasound (say) for imaging. The problem is that high frequencies are absorbed more efficiently by the medium (mostly rock and water) and actually heat it up very slightly. &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;What can you find out with sound?&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;In many cases, we can go beyond an image of the subsurface and deduce some physical properties of the earth, especially the speed of sound in the rock and the density of the rock. Sound reflections depend on changes in &lt;a href=&quot;https://en.wikipedia.org/wiki/Acoustic_impedance&quot; rel=&quot;noreferrer&quot;&gt;acoustic impedance&lt;/a&gt;, and are &lt;a href=&quot;https://en.wikipedia.org/wiki/Zoeppritz_equations&quot; rel=&quot;noreferrer&quot;&gt;dependent&lt;/a&gt; on the incidence angle, so all the physics really stems from that relationship.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;What about acoustic logging?&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Sonic_logging&quot; rel=&quot;noreferrer&quot;&gt;Acoustic logging or sonic logging&lt;/a&gt; is an important counterpart to seismic imaging, because the logs — run along a borehole using special tools — are the best link between the acoustic properties of the rock. They thus link us to the seismic image that depends on those acoustic properties. So we don't image anything with this data, because it's one dimensional, but it's a key calibration point. Acoustic logging does use ultrasound in the 20 kHz range, but the attenuation issue is not a problem in the vicinity of the borehole.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2016-04-04T19:07:46.723" LastActivityDate="2016-04-04T19:07:46.723" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7788" PostTypeId="2" ParentId="7783" CreationDate="2016-04-04T14:23:12.433" Score="4" Body="&lt;p&gt;Not exactly. The PBL is a quantity more or less derived. you may be able to derive it from upper air observations, but a direct observation of it is not yet available. Here are some methods: &lt;a href=&quot;https://e-reports-ext.llnl.gov/pdf/235179.pdf&quot;&gt;https://e-reports-ext.llnl.gov/pdf/235179.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question you are asking is the equivalent of &quot;Can we observe the Jet stream?&quot; We cannot observe the jet stream, but we can observe the winds, from which we infer the jet stream.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2016-04-04T14:23:12.433" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7789" PostTypeId="2" ParentId="7754" CreationDate="2016-04-04T16:50:35.070" Score="8" Body="&lt;p&gt;In addition to all of the above there are meanders inn the Grand Canyon which are hydraulic outcomes of 'minimum energy flow configurations'. This constrains the discharge rates that are possible - to within the normal range of hydrologic discharges.&#xA;Furthermore there are several places in the Grand Canyon where there is clear evidence of the river having been dammed by lava flows, over 13 volcanic episodes. These volcanics have been K-Ar dated at a variety of ages over the last few million years, with each lava dam taking between 10,000 and 20,000 years to erode. &#xA;See, for example &lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC21407/&quot; rel=&quot;noreferrer&quot;&gt;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC21407/&lt;/a&gt;  and several other books and papers on the subject.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-04-04T16:50:35.070" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7790" PostTypeId="2" ParentId="7770" CreationDate="2016-04-04T19:19:00.113" Score="1" Body="&lt;p&gt;A great many volcanoes have really deep magma chambers. At the surface they eject ash clouds or pyroclastics. There are also agglomerate type volcanoes, the deepest of which are kimberlite pipes. So no, don't expect to see lava lakes in many volcanoes.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-04-04T19:19:00.113" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7791" PostTypeId="1" CreationDate="2016-04-05T18:47:00.650" Score="1" ViewCount="133" Body="&lt;p&gt;Is it ok to use biology microscope for &lt;a href=&quot;https://en.wikipedia.org/wiki/Gemology&quot; rel=&quot;nofollow&quot;&gt;gemological&lt;/a&gt; purpose?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What's the difference?&lt;/p&gt;&#xA;" OwnerUserId="5738" LastEditorUserId="595" LastEditDate="2016-04-06T00:16:25.200" LastActivityDate="2016-04-06T00:16:25.200" Title="Is it ok to use biology microscope for gemological purpose?" Tags="|mineralogy|minerals|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7792" PostTypeId="1" AcceptedAnswerId="7802" CreationDate="2016-04-05T21:14:49.233" Score="4" ViewCount="161" Body="&lt;p&gt;Near Prague,Czech Republic is old lime mine. Most of it is closed but one short transport tunnel under one hill is publicly accessible. Tunnel has profile around 2,5x2,5m and it's slightly bended and it's about 100m long. I estimate that hill above it is about 50m high from floor of tunnel. Aproximate location: 50°02'28.0&amp;quot;N 14°22'32.1&amp;quot;E&lt;/p&gt;&#xA;&lt;p&gt;In middle of tunnel this immediately caught my attention, as it was reflecting light from my headlamp a lot. Its like some very wet yellow coating on rock side of tunnel.&lt;/p&gt;&#xA;&lt;p&gt;Area on photo is 2m wide and 1-1,5m high. Tunnel was completely dark, and only source of light was headlamp and flash in my camera so the photo is quite dark&lt;/p&gt;&#xA;&lt;p&gt;According to geological map of area the base rock is Lime and Hornblende from lower devon,emsian&lt;/p&gt;&#xA;&lt;p&gt;What is this coating? I found this site post-trip, so I tried to answer all question in quide as best I can and I can go into that tunnel again and provide all needed information&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/D2MbE.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/D2MbE.jpg&quot; alt=&quot;Strange coating in old lime mine shaft&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5741" LastEditorUserId="-1" LastEditorDisplayName="user12525" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-08-28T08:58:55.117" Title="Strange coating in old lime mine shaft" Tags="|rocks|mineralogy|minerals|mining|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7793" PostTypeId="2" ParentId="7430" CreationDate="2016-04-05T22:46:26.413" Score="1" Body="&lt;p&gt;&lt;strong&gt;Short answer:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oxygen atoms (not oxygen molecules) cause the dominant red and green auroral emissions at high altitudes. Although there is more atomic $\ce{O}$ at higher altitudes than nitrogen, the key to understand the different colours is the excitation energy. Auroral particles with higher energies penetrate deeper down into the atmosphere causing higher energetic emissions at lower altitudes. The excitation leading to the red $\ce{O}$ emission higher up needs less energy than the green $\ce{O}$ emission further down. Even more so, the purple $\ce{N2+}$ emission at the very bottom can only be excited by very energetic particles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Some more details:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You are right to note that molecular oxygen ($\ce{O2}$) is heavier than molecular nitrogen ($\ce{N2}$). Hence, at altitudes above the turbopause at around 105 km, where turbulent mixing ceases to exist because the atmosphere gets too thin, there is relatively more $\ce{N2}$ than $\ce{O2}$ and the ratio between the two increases with altitude. However, there is also strong photodissociation of molecular $\ce{O2}$ to atomic $\ce{O}$. As the recombination of two $\ce{O}$ atoms is slow at high altitudes and the atoms are light, their concentration increases with altitude. Above about 200 km atomic $\ce{O}$ becomes more abundant than $\ce{N2}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As stated before, auroral particles with higher energies deposit more of their energy at lower altitudes where they encounter more collisions with the air. Lower energetic particles don't get that far.&#xA;The dominant red and green emissions of the aurora are basic excitions of the $\ce{O}$ atom. The red emission at around 630 nm peaks at above 200 km. altitude. It's caused by the excited state $\ce{O}^1D$ with an energy of $\sim5.6$ eV. The green emission at around 558 nm peaks at around 110 km, considerably lower than the red emission. The corresponding state $\ce{O}^1S$ has a higher excitation energy of around $10$ eV. Peaking even lower at around 90 km altitude, the violet $\ce{N2+} $ emission has a wavelength around 428 nm and an excitation energy of around $100$ eV.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The combination of the concentrations of the chemical species and, most importantly, the altitude dependent energy deposition result in the altitude dependence of the colours of the aurora. The further to the violet the light, the higher its energy per photon. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that these discussions about what colour is caused by what atom or molecule at what altitude are somewhat simplified. This all only refers to the dominant emission at a certain peak altitude which may overpower fainter colours. To a certain degree, most colours will be emitted from most altitudes, but not be visible to the ground observer. And there are many more colours emitted than the ones discussed.&lt;/p&gt;&#xA;" OwnerUserId="5721" LastActivityDate="2016-04-05T22:46:26.413" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7794" PostTypeId="2" ParentId="4816" CreationDate="2016-04-05T22:55:12.213" Score="1" Body="&lt;p&gt;Looking at your picture I would say it was most likely not taken facing in the direction of the setting sun, but perpendicular to it. What you see as a colour gradient is most likely the shadow of the Earth. I suspect if you took a series of pictures you'd see the shadow (your gradient) moving upwards and becoming steeper while the sun sets deeper behind the horizon. &lt;/p&gt;&#xA;" OwnerUserId="5721" LastActivityDate="2016-04-05T22:55:12.213" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7795" PostTypeId="2" ParentId="7783" CreationDate="2016-04-06T06:12:37.087" Score="3" Body="&lt;p&gt;The PBL depth is not easy to observe. It is the layer where the atmosphere is turbulent due to friction at the surface and convection. During daytime this leads to well-mixed potential temperature and specific humidity profiles and you can estimate where the well-mixed area ends. This, however, is complex, because you need accurate measurements of that. Even in radio-soundings it is hard to find the top of the PBL.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With more advanced equipment, as a ceilometer, you can use backscatter profiles, but these are more local measurements.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short, a world wide set does not exist and probably (re)analysis data is the best you can get.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An interesting analysis can be found here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://kiwi.atmos.colostate.edu/pubs/Ahlgrimm-Randall.2006.pdf&quot; rel=&quot;nofollow&quot;&gt;http://kiwi.atmos.colostate.edu/pubs/Ahlgrimm-Randall.2006.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5689" LastEditorUserId="5689" LastEditDate="2016-04-06T08:20:35.227" LastActivityDate="2016-04-06T08:20:35.227" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7798" PostTypeId="1" CreationDate="2016-04-06T15:42:29.263" Score="10" ViewCount="518" Body="&lt;p&gt;I'm playing around with NOAA's GFS forecast data and I see that it contains both a &amp;quot;0 °C isotherm level&amp;quot; and a &amp;quot;Highest tropospheric freezing level&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Could someone tell me the difference between these two levels? I'd assume they are the same except in the case of an inversion.&lt;/p&gt;&#xA;" OwnerUserId="4879" LastEditorUserId="2470" LastEditDate="2022-02-03T09:34:37.713" LastActivityDate="2024-02-23T13:07:30.883" Title="What is the difference between the freezing level and 0 C isotherm in NOAA's GFS?" Tags="|meteorology|models|weather-forecasting|gfs|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="7799" PostTypeId="1" AcceptedAnswerId="7806" CreationDate="2016-04-06T16:07:17.887" Score="4" ViewCount="158" Body="&lt;p&gt;The &lt;a href=&quot;http://www.atlasobscura.com/places/earthquake-fence-skb&quot; rel=&quot;nofollow&quot;&gt;earthquake fence at Olema&lt;/a&gt; shows the sudden transform motion along the San Andreas caused by the 1906 earthquake. 110 years on, has there been ANY additional displacement?&lt;/p&gt;&#xA;" OwnerUserId="4611" LastEditorUserId="595" LastEditDate="2016-04-08T08:38:45.823" LastActivityDate="2017-05-19T00:42:16.897" Title="Has the Olema earthquake fence continued to spread apart?" Tags="|earthquakes|california|transform-fault|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7801" PostTypeId="1" AcceptedAnswerId="7812" CreationDate="2016-04-06T19:00:27.607" Score="4" ViewCount="581" Body="&lt;p&gt;Why does lithostatic pressure not play a role? (or does it?)&lt;/p&gt;&#xA;" OwnerUserId="5748" LastEditorUserId="5748" LastEditDate="2016-04-08T11:08:15.963" LastActivityDate="2016-04-08T12:55:12.673" Title="Why is fluid pressure in a fractured rock reservoir only dependent on hydrostatic pressure?" Tags="|geophysics|geothermal-heat|groundwater|hydrogeology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7802" PostTypeId="2" ParentId="7792" CreationDate="2016-04-06T19:17:08.960" Score="5" Body="&lt;p&gt;Given your description of the base rock and the age of the mine I would suggest that what you are seeing is what in a cave we would refer to as flow stone (A deposit of Calcium Carbonate in one or more of many crystal structures).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Simplified Process:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ground water often has varying degrees of dissolved carbon dioxide in it.  This carbon dioxide within the water creates a mild acid, carbonic acid.  The acid in the ground water will corrode out Calcium Carbonate in the base rock.  Most ground water will be saturated with Calcium Carbonate, the lime, depending on the concentration of dissolved carbon dioxide in the water.  When the water seeps out of the walls of the mine it has an opportunity to off gas some of the dissolved carbon dioxide.  When this occurs the water can no longer hold as much dissolved Calcium Carbonate and the excess is deposited on the walls in various forms.  The mechanism of dissolving the rock and re-deposition is driven by various equilibrium reactions( involving temperature, water mixing, partial pressures of the gases...).  A karst hydrologist/geologist would be able to give you much more detailed information on the processes. It is this process that forms caves and causes the formations with the caves to form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following web site gives a pretty straight forward explanation of what I believe you are seeing. &lt;a href=&quot;https://en.wikipedia.org/wiki/Karst&quot;&gt;https://en.wikipedia.org/wiki/Karst&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2016-04-06T19:17:08.960" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7803" PostTypeId="1" AcceptedAnswerId="7805" CreationDate="2016-04-07T03:35:57.237" Score="2" ViewCount="760" Body="&lt;p&gt;I gather that chemical sedimentary rocks are formed when minerals in solution are supersaturated and therefore they precipitate out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also understand that desert sandstone is formed as Iron Oxide rich water evaporates leaving a hematite cement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does this mean Desert Sandstone is a chemical sedimentary rocks?&lt;/p&gt;&#xA;" OwnerUserId="5711" LastEditorUserId="5711" LastEditDate="2016-04-07T04:22:11.767" LastActivityDate="2016-04-07T10:57:59.300" Title="Is Desert Sandstone a chemical sedimentary rock?" Tags="|geology|sedimentology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7804" PostTypeId="2" ParentId="7280" CreationDate="2016-04-07T07:15:18.577" Score="3" Body="&lt;p&gt;What is usually shown in cyclic plots showing precession is the &lt;em&gt;precession index&lt;/em&gt; ($e \cdot \sin\varpi$ where $e$ is the eccentricity and $\varpi$ is the moving &lt;a href=&quot;https://en.wikipedia.org/wiki/Longitude_of_the_periapsis&quot; rel=&quot;nofollow noreferrer&quot;&gt;longitude of the perihelion&lt;/a&gt;). It is dimensionless ($e$ and $\sin \varpi$ being ratios).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is the precession index for the last 2 Myrs that I plotted using &lt;a href=&quot;http://vo.imcce.fr/insola/earth/online/earth/La2004/INSOLN.LA2004.BTL.100.ASC&quot; rel=&quot;nofollow noreferrer&quot;&gt;data&lt;/a&gt; from &lt;a href=&quot;http://dx.doi.org/10.1051/0004-6361:20041335&quot; rel=&quot;nofollow noreferrer&quot;&gt;Laskar et al. (2004)&lt;/a&gt; (in the data file, first column is the age, second the eccentricty, third the obliquity and fourth the longitude of perihelion from moving equinox):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ZyOYS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZyOYS.png&quot; alt=&quot;Precession cycles&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the range of values, by definition a $\sin$ can only take values on the range [-1,1], while the eccentricity (at least during the last 100Myrs) has values ranging from 0 to 0.067; hence a resulting precession index ranging in theory from -0.067 to 0.067.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Laskar, J., Robutel, P., Joutel, F., Gastineau, M., Correia, A. C. M., &amp;amp; Levrard, B. (2004). A long-term numerical solution for the insolation quantities of the Earth. &lt;em&gt;Astronomy &amp;amp; Astrophysics&lt;/em&gt;, &lt;em&gt;428&lt;/em&gt;(1), 261–285.&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2016-04-08T08:20:27.403" LastActivityDate="2016-04-08T08:20:27.403" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7805" PostTypeId="2" ParentId="7803" CreationDate="2016-04-07T10:57:59.300" Score="3" Body="&lt;p&gt;No, it's not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The overwhelming majority of the material in the rock is clastic, not chemical. Chemical sedimentary rocks are rocks where (almost) all of the material was precipitated, such as travertine, evaporites, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cementation is a chemical process. As a clastic sedimentary rock has to be cemented somehow, otherwise it would be a sediment rather than a rock, all clastic sedimentary rocks have undergone some chemical process. This does not mean that they are chemical though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As diagenesis progresses and the rock undergoes more chemical changes it may become a diagenetic clastic sedimentary rock of even a metamorphic one, but never a chemical sedimentary rock. This implies that most, if not all, of its initial mass precipitated out of solution.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-04-07T10:57:59.300" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7806" PostTypeId="2" ParentId="7799" CreationDate="2016-04-07T14:15:40.893" Score="5" Body="&lt;p&gt;If your question is only about the location of said fence I can not answer it. If, however, you are interested in the greater area around that location or the San Andreas fault in General, the short answer is, yes, there has been additional displacement and the movement is ongoing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This displacement is related to what one can call the earthquake cycle of surface deformation. Usually people differentiate between co-seismic (directly caused by an earthquake, the Olema fence is a beautiful example for this), post-seismic (caused by secondary earthquake effects, keywords are poroelastic and viscoelastic effects) and inter-seismic (which is the tectonically driven creep of a fault in between earthquakes).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take a look at &lt;a href=&quot;http://sci-hub.io/10.1029/91JB00199&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; by Lisowski and others to see surface displacements along the SAF. Fig. 7 shows the area of interest and , though a bit hard to see, there is significant relative motion in between areas east and west of the fault. The number that they give for average relative plate motion is 35 mm/yr (which would be roughly 4m/13ft in 110 yrs).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To return to the fence, I can only assume that it has spread further apart in the last 110 years, but not having been there I can not be certain. It is possible, that the surface manifestation of the fault has turned to another spot. I do think it is unlikely that not at least part of the deformation can be seen at the fence's location. According to &lt;a href=&quot;https://books.google.is/books?id=LskrBgAAQBAJ&amp;amp;pg=SA1-PA15&amp;amp;lpg=SA1-PA15&amp;amp;dq=offset+of+the+olema+fence&amp;amp;source=bl&amp;amp;ots=apWId7LU31&amp;amp;sig=fk6LRQ39vscGnA5617QKoHPLQ34&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwjVlveq3fzLAhWsC5oKHV2ECfEQ6AEILzAE#v=onepage&amp;amp;q=offset%20of%20the%20olema%20fence&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; book the co-seismic offset of the fence was 4.7 m, might be interesting to know what it is today.&lt;/p&gt;&#xA;" OwnerUserId="5748" LastEditorUserId="5748" LastEditDate="2017-05-19T00:42:16.897" LastActivityDate="2017-05-19T00:42:16.897" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7808" PostTypeId="2" ParentId="7798" CreationDate="2016-04-08T00:25:16.967" Score="0" Body="&lt;p&gt;Various processes affect the freezing point. Both CCN (cloud condensation nuclei) characteristics and drop size affect the freezing point.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2016-04-08T00:25:16.967" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7810" PostTypeId="5" CreationDate="2016-04-08T08:31:59.717" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2016-04-08T08:31:59.717" LastActivityDate="2016-04-08T08:31:59.717" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7811" PostTypeId="4" CreationDate="2016-04-08T08:31:59.717" Score="0" Body="Questions relating to Historical Geology." OwnerUserId="87" LastEditorUserId="87" LastEditDate="2016-04-08T13:57:54.283" LastActivityDate="2016-04-08T13:57:54.283" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7812" PostTypeId="2" ParentId="7801" CreationDate="2016-04-08T12:55:12.673" Score="2" Body="&lt;p&gt;&lt;strong&gt;Fluid (or 'pore') pressure does not depend only on hydrostatic pressure — it also depends on stratigraphy, fluid content, and the geological history of the rock.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fluid 'stack' can be thought of as a (mostly) connected body of fluid — dominantly brine and hydrocarbons. The rock 'stack' is a similarly interconnected body. The fluid stack defines a typical soft lower limit of pore pressures; the rock stack defines the hard upper bound.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In practice, we don't experience lithostatic pressure in the pores because at some level of stress below lithostatic pressure, we find the &lt;em&gt;fracture pressure&lt;/em&gt;. If the pore pressure reaches this level, the rock breaks and pressure equilibrates. This is the mechanism behind &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydraulic_fracturing&quot; rel=&quot;nofollow noreferrer&quot;&gt;induced hydraulic fracturing, or fracking&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;But pore pressure does not have to be hydrostatic.&lt;/strong&gt; &lt;a href=&quot;https://en.wikipedia.org/wiki/Geologic_overpressure&quot; rel=&quot;nofollow noreferrer&quot;&gt;'Geopressure' or 'overpressure'&lt;/a&gt; or &lt;a href=&quot;http://www.glossary.oilfield.slb.com/Terms/u/underpressure.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;underpressure&lt;/a&gt; can occur if a stratigraphic layer is unusually tight, for example salt, and a porous formation experiences rapid uplift or burial. We might also depart from hydrostatic pressure as the density of the pore fluid changes, with salinity or gas saturation for example.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DNEh4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DNEh4.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This cartoon shows pressure measurements (green) in a gas well. The other trends can be computed from models or data (for example the bulk density log). The shallow part of the well is hydrostatic; the deeper section shows overpressure. Natural gas is low density, so the gas zone shows a different trend. Clearly there will be a potentially dangerous pressure kick as the drill penetrates the top of the reservoir. If the gas trend were to hit fracture pressure, the trap would leak and the hydrocarbons would escape — a common natural phenomenon.&lt;/p&gt;&#xA;&#xA;&lt;hr /&gt;&#xA;&#xA;&lt;p&gt;You might also like to read these related questions:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/2992/why-is-the-lithostatic-pressure-gradient-1-psi-ft-how-is-it-derived-from-densit&quot;&gt;Why is the lithostatic pressure gradient 1 psi/ft? How is it derived from density?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/2106/how-do-i-derive-the-formula-for-lithostatic-overburden-pressure&quot;&gt;How do I derive the formula for lithostatic (overburden) pressure?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/2283/what-is-the-reasoning-behind-the-statement-faulting-will-occur-along-the-plane&quot;&gt;What is the reasoning behind the statement &amp;quot;Faulting will occur along the plane where the shear stress is the highest&amp;quot;?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-04-08T12:55:12.673" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7813" PostTypeId="1" CreationDate="2016-04-08T15:05:00.930" Score="5" ViewCount="998" Body="&lt;p&gt;Upon watching all the videos from &lt;a href=&quot;https://www.youtube.com/channel/UCAL3JXZSzSm8AlZyD3nQdBA&quot; rel=&quot;noreferrer&quot;&gt;PrimitiveTechnology on Youtube&lt;/a&gt;, I've decided I would try something similar. I know how to make clay and use this to make an oven. I also know how to make charcoal. Looking at the temperature I could achieve with charcoal, I realized it can melt certain metals. That said, finding metal ores in nature is probably no easy task. That's why I came here, I've searched online for every possible way to find iron, and the &quot;easiest&quot; (most likely) way is by finding bog iron. Now, suppose I can't find any iron, is there a material (except rock) that I could use to make tools (better than rock)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm trying to find a way to make better tools to see how someone in nature could make this without any starting tools (mainly pick).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, I live in Canada (QC), if this can help.&lt;/p&gt;&#xA;" OwnerUserId="5757" LastActivityDate="2021-07-24T04:20:11.807" Title="Mining iron or metals in nature" Tags="|minerals|mining|iron|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7814" PostTypeId="1" CreationDate="2016-04-08T19:30:35.277" Score="2" ViewCount="179" Body="&lt;p&gt;After coming across this article &lt;a href=&quot;http://www.climatecentral.org/news/climate-change-polar-motion-20229#article-comments&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;, and reading the paper &lt;a href=&quot;http://advances.sciencemag.org/content/2/4/e1501693.full&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt; I came away with the impression that the authors were saying that &lt;a href=&quot;https://en.wikipedia.org/wiki/Polar_wander&quot; rel=&quot;nofollow&quot;&gt;polar wander&lt;/a&gt; is being affected by climate change due to mass rebalancing as ice caps melt. As I understand it, the magnetic field of Earth derives from the liquid outer core, and due to the sheer mass difference between the core and any surface mass losses, combined with the lost mass being rebalanced isostatically, such a theory seems on first glance improbable. Could someone with more knowledge perhaps explain how the proposed theory operates?&lt;/p&gt;&#xA;" OwnerUserId="140" LastEditorUserId="94" LastEditDate="2016-04-11T10:02:03.733" LastActivityDate="2016-04-16T06:49:03.590" Title="Is this paper attributing a change in polar wander to climate change?" Tags="|climate-change|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7816" PostTypeId="2" ParentId="7814" CreationDate="2016-04-09T07:15:07.057" Score="6" Body="&lt;p&gt;The term ‘polar wander’ is ambiguous. In this case it's got nothing to do with the magnetic poles, but rather with the Earth's spin axis. If you think about a desk globe mounted on an axle, the poles under consideration here are the points where the axle intersects the globe's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The paper is essentially saying that climate changes are changing the distribution of ice and water on the surface of the planet, and this in turn is shifting the spin axis slightly. You're right that the mass of material on the Earth's surface is dwarfed by the mass under the surface; however, if you look at the paper you'll see that they're talking about miniscule shifts in the axis. The changes shown in Figure 1 are on the order of tens of mas (milliseconds of arc) over a few decades. One mas is one 3.6-millionth of a degree, or about 3.09 cm as measured on the Earth's surface. So, at least at first glance, the changes don't seem too implausible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You mention isostatic response as another concern, but this is a slow process which doesn't really come into play on the decadal time scales considered in the paper. Fennoscandia and northern North America are still rebounding isostatically from the last ice age.&lt;/p&gt;&#xA;" OwnerUserId="94" LastActivityDate="2016-04-09T07:15:07.057" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7818" PostTypeId="2" ParentId="3127" CreationDate="2016-04-11T02:59:40.117" Score="0" Body="&lt;p&gt;A much larger or much closer moon would strip away the atmosphere over time. Heavier elements would go first, so the composition would change, yes.&lt;/p&gt;&#xA;" OwnerUserId="152" LastActivityDate="2016-04-11T02:59:40.117" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7819" PostTypeId="2" ParentId="2538" CreationDate="2016-04-11T03:57:00.417" Score="3" Body="&lt;p&gt;The absolute accuracy for GOES-13 visible channel is 5%, so 2% is well within the noise. &lt;a href=&quot;http://noaasis.noaa.gov/NOAASIS/ml/imager.html&quot; rel=&quot;nofollow&quot;&gt;http://noaasis.noaa.gov/NOAASIS/ml/imager.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="152" LastActivityDate="2016-04-11T03:57:00.417" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7823" PostTypeId="1" AcceptedAnswerId="7826" CreationDate="2016-04-11T16:30:09.587" Score="2" ViewCount="202" Body="&lt;p&gt;I have an excel file that I have to make the join with another table that has a column listed of different kind of feature types. This was done by someone else who did GPS'ed and spell that word and handed it out to me to do the spatial join with a point layer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What does Stock or Overflow Pit? Is it related to geography or geomorphology term? Is there another word that is similar to it? I tried to Google it but with no luck. I looked it up on the image on the google to find it and still have no luck. Would someone out there helped me what they are or what does it look like?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: This was post in the GIS StackExchange and it's not approiate to post it since it is not related to GIS.&#xA;&lt;a href=&quot;https://gis.stackexchange.com/questions/188827/what-is-stock-or-overflow-pit-is-it-a-terminology-in-geography?noredirect=1#comment284729_188827&quot;&gt;https://gis.stackexchange.com/questions/188827/what-is-stock-or-overflow-pit-is-it-a-terminology-in-geography?noredirect=1#comment284729_188827&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5771" LastEditorUserId="-1" LastEditDate="2017-04-13T12:33:47.360" LastActivityDate="2016-04-11T22:16:37.100" Title="What is Stock or Overflow Pit? Is it a terminology in geography? What is the correct word for it?" Tags="|geography|geomorphology|terminology|" AnswerCount="1" CommentCount="3" ClosedDate="2016-04-13T00:34:26.020" ContentLicense="CC BY-SA 3.0" />
  <row Id="7824" PostTypeId="1" CreationDate="2016-04-11T17:17:51.383" Score="1" ViewCount="127" Body="&lt;p&gt;My question is about how vertical component of wind may change over time; in particular, as I am interested in simulating the effect of vertical wind on flight mechanics, I'd like to know whether I should consider vertical wind as a deterministic function of time or a stochastic one. Furthermore, should I consider vertical wind persistent over time or having a limited duration (e.g. few seconds)?&#xA;Note that I am not interested in horizontal wind.&lt;/p&gt;&#xA;" OwnerUserId="5772" LastEditorUserId="5772" LastEditDate="2016-04-15T08:43:37.587" LastActivityDate="2016-04-15T08:43:37.587" Title="How does vertical wind change over time?" Tags="|wind|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="7825" PostTypeId="1" AcceptedAnswerId="7832" CreationDate="2016-04-11T18:43:32.500" Score="2" ViewCount="530" Body="&lt;p&gt;I want to add nitrogen to my soil samples in a lab as fertilizer (ammonium nitrate). I need to add it equivalent of 50 kgN/ha. I have a clump of soil, that weighs 20g. What is the best way to convert it to concentration, molarity or any other measure of how to prepare my fertilizer solution without knowing density, depth or any similar physical properties of the soil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically, I would like to know if there is a way to convert nitrogen load from kg/ha to 20 gr. Thanks everyone in advance!&lt;/p&gt;&#xA;" OwnerUserId="5773" LastEditorUserId="1242" LastEditDate="2016-04-18T03:39:39.740" LastActivityDate="2017-06-13T09:32:07.960" Title="How to find molarity of a fertilizer?" Tags="|soil|agriculture|nitrogen|laboratory|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7826" PostTypeId="2" ParentId="7823" CreationDate="2016-04-11T22:16:37.100" Score="1" Body="&lt;p&gt;Never mind I think I found what it is...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is a tank that has a stock pit on the allotment. The tank usually about 30 feet radious and has a windmill.  It looks like this &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.panoramio.com/photo/9687839&quot; rel=&quot;nofollow&quot;&gt;http://www.panoramio.com/photo/9687839&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5771" LastActivityDate="2016-04-11T22:16:37.100" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7827" PostTypeId="1" CreationDate="2016-04-12T09:43:29.083" Score="4" ViewCount="154" Body="&lt;p&gt;Why is there a logarithmic grid when these &lt;a href=&quot;https://en.wikipedia.org/wiki/Well_logging&quot; rel=&quot;noreferrer&quot;&gt;wireline density and neutron porosity logs&lt;/a&gt; have linear scale labels, and when these logs are usually displayed on linear scales?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fmnfY.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fmnfY.jpg&quot; alt=&quot;Part of wireline log printout&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5578" LastEditorUserId="28050" LastEditDate="2016-04-13T13:52:28.473" LastActivityDate="2016-04-13T18:26:16.590" Title="Why is there a logarithmic grid on this plot?" Tags="|data-formats|visualization|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7828" PostTypeId="1" AcceptedAnswerId="7830" CreationDate="2016-04-12T10:39:13.857" Score="5" ViewCount="894" Body="&lt;p&gt;I recently conducted a brief training exercise with VES equipment, although it had to be called off due to rain. I can't help but wonder about the basic physics of it, why is it that increased distance between the electrodes results in an increased depth of investigation? See the image below for an example, see the difference between A1 and B1, vs A2 and B2&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7Xwhu.jpg&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7Xwhu.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5775" LastActivityDate="2016-04-12T13:13:49.570" Title="How does Vertical Electrical Sounding Work?" Tags="|geophysics|geology|structural-geology|geologic-layers|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7830" PostTypeId="2" ParentId="7828" CreationDate="2016-04-12T13:13:49.570" Score="4" Body="&lt;p&gt;The diagram is perhaps a little mis-leading.&#xA;Think of the ground/rock between the electrodes as a big resistor. The surrounding rock can be modeled as a set of parallel resistors. Most of the electrons will take a direct straight line route between the electrodes, but some of them flow through this surrounding rock, so increasing the current and reducing the measured resistance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In theory this parallel resistor model could go off to infinity (or the other side of the Earth), however if the probes are close together, then the resistance for the electrons to go down and then back up counteract any reduction in overall resistance. Yes there's a contribution but it is vanishingly small.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Move the probes further apart and rock of varying depths (and widths) can add effective current carrying capacity - as per the diagram. Just remember that for the outer probes, the electrons are also moving horizontally, as well as in the deeper tracks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what you measure is a composite effect of many depths. By moving the electrodes further apart, you can sample deeper, but you are still measuring a composite resistance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This makes interpretation difficult! In fact, the only time I've seen or known a Schlumberger or Wiener array being used, was in a student demo that I participated in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Resistance is much more practical in the archaeological domain. Here, two electrodes are left at a base station, and two are moved around in a sampling frame (rather like a zimmer frame or walker). Then you are sampling shallow variations localized to the frame-mounted electrodes. Eg. shallow stones, charcoal, etc. The resulting images are much easier to interpret and often appear on TV shows like Time Team, Discovery Channel, etc.&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2016-04-12T13:13:49.570" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="7831" PostTypeId="1" AcceptedAnswerId="7844" CreationDate="2016-04-13T03:41:00.277" Score="2" ViewCount="9039" Body="&lt;p&gt;I used some copper pipe outside to string some decorative lights up higher in my yard. I used the copper because I thought it would be pretty and patina nice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then I remembered that copper is a good conductor, and there's a lightning storm outside. Should I be concerned about attracting lightning strikes? It's not grounded.&lt;/p&gt;&#xA;" OwnerUserId="5614" LastEditorUserId="5614" LastEditDate="2016-04-19T19:46:27.100" LastActivityDate="2022-03-30T00:50:09.953" Title="Should I worry about copper pipe outside attracting lightning strikes?" Tags="|meteorology|lightning|extreme-weather|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7832" PostTypeId="2" ParentId="7825" CreationDate="2016-04-13T09:09:10.957" Score="3" Body="&lt;p&gt;You probably mean 50kgN/ha, which sounds like a plausible number for fertilizer application.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know what you are doing exactly, but you need to know how much surface area your soil sample represents. If you do planting tests, it will be simply the surface of your bed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then it's just mulitplying the surface area by 50kgN/ha (mind the units!). Now you know how much N you need.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you buy fertilizer, the fertilizer value in kg/t, kg/m³ or some similar measure will be given for the important macronutrients NPK. Else you need to know how much N is in Ammonia per weight but I think that is the easy part.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Disclaimer: I've never done any soil science, but I worked with farmers for a while and was in a field where fertilizer etc. matters.&lt;/p&gt;&#xA;" OwnerUserId="117" LastActivityDate="2016-04-13T09:09:10.957" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7833" PostTypeId="2" ParentId="7827" CreationDate="2016-04-13T18:26:16.590" Score="5" Body="&lt;p&gt;&lt;strong&gt;It's a mistake.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You probably know this, but for anyone who's interested, these wireline logs are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;DRHO&lt;/strong&gt; — &lt;a href=&quot;https://www.spec2000.net/07-densitylog.htm&quot;&gt;density&lt;/a&gt; ('RHO') correction (delta, or 'D') in g/cc.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;DPHI&lt;/strong&gt; — porosity ('PHI') from &lt;a href=&quot;https://www.spec2000.net/07-densitylog.htm&quot;&gt;density&lt;/a&gt; ('D'), as a fractional proportion.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;NPHI&lt;/strong&gt; — porosity from &lt;a href=&quot;https://www.spec2000.net/07-neutronlog.htm&quot;&gt;the neutron log&lt;/a&gt; ('N'), as a fractional proportion.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;All of these logs are usually displayed on a linear scale. Indeed it wouldn't make sense to display them on a log scale, which is mainly for displaying resistivity logs, e.g. &lt;a href=&quot;https://www.spec2000.net/07-indlog.htm&quot;&gt;the induction log&lt;/a&gt;. Even if they were, it wouldn't make sense to show the usual 4 octaves (0.2 to 2000 for resistivity), given the range of the data and the scale of porosity values geologists are interested in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's not clear if the data have actually been displayed on a log scale, or if it's just that the grid has been erroneously added. I would treat the data with suspicion.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2016-04-13T18:26:16.590" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7834" PostTypeId="2" ParentId="7824" CreationDate="2016-04-14T03:31:40.783" Score="1" Body="&lt;p&gt;There are a number of causes, for a variety of scales.&#xA;Generally speaking, you can boil it down to convergence/divergence, as a continuity of mass problem, or buoyant motion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can refer to the vertical component of the Navier Stoke's equations.&#xA;$$&#xA;\frac{Dw}{Dt}=\frac{∂w}{∂t}+\vec{v}\cdot\nabla w + w\frac{∂w}{∂z} =-\frac{1}{ρ}\frac{∂P}{∂z}-g+\nu\nabla^2w&#xA;$$&#xA;Additionally, it must also be constrained by the conservation of mass.&#xA;$$&#xA;\frac{∂P}{∂t}=-\nabla\cdot(\rho\vec{v})&#xA;$$&#xA;The Quasigeostrophic Omega Equation may also provide you some insight. This equation is filtered down from the above Navier-Stokes equation, though it may not seem like it. Omega is vertical velocity in pressure coordinates.&#xA;$$&#xA;(\nabla^2+\frac{f_0^2∂^2}{\sigma∂\Phi^2})\omega=\frac{f∂}{\sigma∂p}(\vec{v}\cdot\nabla(\frac{1}{f_0}\nabla^2\Phi+f)) + \frac{1}{\sigma}\nabla^2[\vec{v_g}\cdot\nabla(-\frac{∂\Phi}{∂p})]&#xA;$$&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2016-04-14T03:31:40.783" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7836" PostTypeId="1" CreationDate="2016-04-14T19:58:19.893" Score="4" ViewCount="80" Body="&lt;p&gt;I have generated a synthetic seismogram using FDTD elastic velocity-stress formulation on a staggered grid. I can't understand origin of oscillations modulating on seismogram. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/HggTo.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HggTo.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it a result of dispersion? &#xA;I have satisfied the grid dispersion criteria (10 grid per minimum wavelength) which keeps it below 5% but still it is very prominent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Model description:&#xA;Velocities: Vp = 2000 m/s;  Vs = 1500 m/s;&#xA;Source:  Ricker (20Hz).&#xA;Grid spacing:  dx = dv = 1m;&#xA;time sampling: dt = 0.1msec&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit 1&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have corrected one problem related to source (now I am using soft source) and it made initial pulse smooth. However its tail still have oscillations.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/j2BN0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/j2BN0.jpg&quot; alt=&quot;Pressure corrected&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5413" LastEditorUserId="5413" LastEditDate="2016-04-22T16:36:57.860" LastActivityDate="2016-04-22T16:36:57.860" Title="Unwanted oscillations in Synthetic seismogram" Tags="|numerical-modelling|seismic|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="7837" PostTypeId="2" ParentId="7266" CreationDate="2016-04-15T01:58:29.037" Score="5" Body="&lt;p&gt;The base of the Richter scale is empirical. In terms of energy released, the best fit for the base turns out to be about 31. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since 31**2 is close to 1000, two points on the Richter scale e.g., from 4 to 6 or from 5 to 7, corresponds to about 1000 times the energy release. Each point piles on another factor of (empirically about) 31. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is so widely misquoted on the web that it is becoming sort of urban legend that the base of the logarithm is 10. To see people trying the empirical best fit and arriving at a base of about 31, you need to dig into the scholarly literature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;UPDATE: Although the main wikipedia titled &quot;Richter magnitude scale&quot; isn't very helpful, it turns out there is another article titled &lt;a href=&quot;https://en.wikipedia.org/wiki/Moment_magnitude_scale&quot; rel=&quot;nofollow&quot;&gt;&quot;Moment magnitude scale&quot;&lt;/a&gt; that has the quantitive explanation. It might be helpful when reading that article to keep in mind that although e and 10 are the most common logarithmic bases, you can define a logarithm with any base. For example, software people might use that log base 2 of 64 is 6 (this is 100% equivalent to saying 2^6 = 64). The upshot is that seismologists have found that using 10^1.5 as the base for the modern scale fits the original Richter scale well, and 10^1.5 is about 31.62.&lt;/p&gt;&#xA;" OwnerUserId="5795" LastEditorUserId="5795" LastEditDate="2016-05-17T17:22:15.873" LastActivityDate="2016-05-17T17:22:15.873" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7838" PostTypeId="1" CreationDate="2016-04-15T17:52:39.493" Score="1" ViewCount="32" Body="&lt;p&gt;In sampling vegetation, what is the size of a quadrat needed?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And I need a reference too plz.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the type matters, pick any vegetation all I need is an example of crops and the quadrat size. With reference ofcourse.&lt;/p&gt;&#xA;" OwnerUserId="5797" LastActivityDate="2016-04-15T17:52:39.493" Title="Can anyone give share reference for quadrat size in vegetation" Tags="|statistics|vegetation|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7839" PostTypeId="2" ParentId="4931" CreationDate="2016-04-15T19:45:33.447" Score="5" Body="&lt;p&gt;There are a few things that come into play when you talk about the radiative forcing of clouds, or their effect on the climate budget. &quot;Cloud&quot; is a pretty wide-sweeping definition. Scientists are still trying to fully understand and quantify these effects. Clouds do not vary only in where they are in the atmosphere but also in their phase (ice versus mixed phase versus water) and their depth--the combination of these two affect the cloud's optical depth. All of these different properties affect the net effect (whether positive, negative, or neutral) of clouds on the climate system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;High clouds are generally ice crystals, yes, because they are in areas of the atmosphere that are far colder than the freezing level. They are also generally geometrically thin. These high clouds have little effect on the shortwave energy and instead mainly reduce the amount of longwave radiation leaving the planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clouds in the middle parts of the atmosphere are usually tall cumulus clouds that are full of liquid and mixed phase precipitation. These will be very bright to shortwave radiation and thus reflect much of that incoming radiation. They also provide some trapping of longwave emission from the surface and radiate less longwave radiation for a given level in the atmosphere than would normally be the case. The anvil regions of these clouds, on the other hand, are full of ice crystals which again don't reflect much shortwave radiation but do reduce the amount of longwave radiation leaving the planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Compared with the high atmosphere, completely ice phase clouds near the surface are thicker and their shortwave reflection is therefore a bit stronger than their thinner counterparts in the middle and upper atmosphere; they also trap longwave radiation from the surface. Mixed and liquid phase clouds' effects have similar effects as ice phase but are stronger in both the short- and longwave spectra.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another thing special about clouds near the surface is because of that proximity they can actually have a strong influence on the surface which can cause a climate feedback. If you have a deck of clouds overlying a bright surface, it can actually warm the surface a bit since it is reflecting less shortwave than the highly reflective underlying surface would otherwise. For example, it has been hypothesized that the Greenland Ice Sheet melting is enhanced when cloud cover is present.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good resource on this topic is available &lt;a href=&quot;http://earthobservatory.nasa.gov/Features/Clouds/&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;. There have been many hypotheses over the years as to how these clouds and their effects will change in a changing climate. You can search for things like the &quot;Iris hypothesis&quot;--and subsequent refutation--as a good example of this still-evolving science. Climate models are still struggling to cope with correctly representing all of the feedbacks associated with clouds, which causes such high uncertainty in cloud effects in the IPCC reports.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One last thing to keep in mind is that these forcings are relative to a column with no cloud in the current climate. But what if our distributions or regimes of clouds greatly shift? If the planet warms so much that ice clouds can never exist, the relative forcing of ice clouds in that climate would then be null. So akeep in mind the point of reference you are using when thinking about the forcing of clouds.&lt;/p&gt;&#xA;" OwnerUserId="4839" LastEditorUserId="4839" LastEditDate="2016-04-15T19:57:31.230" LastActivityDate="2016-04-15T19:57:31.230" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7840" PostTypeId="2" ParentId="7737" CreationDate="2016-04-15T20:26:38.117" Score="7" Body="&lt;p&gt;Has Earth's climate ever changed? Sure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/ggon2.gif&quot; alt=&quot;paleoclimate record&quot;&gt;&#xA;[&lt;a href=&quot;http://www.giss.nasa.gov/research/briefs/hansen_15/&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are many feedbacks within the climate system, some negative as you mention but some also positive. A well-known positive feedback is the greenhouse gas effect, which in the present age is caused by anthropogenic fossil fuel emissions. Increasing greenhouse gases (GHG) causes the atmosphere to trap more longwave radiation and increase the temperature. Negative feedbacks can occur in the climate, such as the &quot;Planck&quot; feedback which describes the T$^4$ dependence of radiation emission--so as the planet warms it emits an even larger amount of radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Climate models already take into account many of these feedbacks, but one of the largest unknowns is the effects of clouds and aerosols on the climate. The distribution of phase of clouds may change as the climate changes, which could possibly counteract the warming (as made popular in the hotly-contested Iris hypothesis [&lt;a href=&quot;https://en.wikipedia.org/wiki/Iris_hypothesis&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;]) or further enhance the warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A forcing related to clouds that further complicates their feedback is the aerosols that they form on. Let's say the climate warms a lot and the planet goes into a major drought. That will cause more deserts which will increase the amount of dust in the air. That dust (for a given amount of water) could potentially suppress precipitation in the clouds, thereby extending their lifetime and increasing the amount of sunlight reflected. Without fully knowing the distribution and effects of aerosols (and their respective impacts on clouds), an accurate estimate of cloud feedbacks is difficult.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A runaway effect on Earth could technically be possible. You talk about feedbacks as a mechanism to prevent that, but some mechanisms are not easily reversible. Thinking about the ice coverage in Earth's polar regions, if all of that ice melts for a given increase in T, decreasing T does not necessarily allow that ice to grow back to the same coverage...and especially not at the same rate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So a changing climate is a complex system with many different interrelated components that cannot simply be predicted by a $dT/dt = dGHG/dt$ relationship. There are numerous feedbacks that are all dependent not only on each other but also sometimes-irreversible processes.&lt;/p&gt;&#xA;" OwnerUserId="4839" LastActivityDate="2016-04-15T20:26:38.117" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7841" PostTypeId="1" AcceptedAnswerId="7849" CreationDate="2016-04-16T04:45:38.953" Score="5" ViewCount="130" Body="&lt;p&gt;Given a distribution obeying the power-law (fractal) relation, such as the cumulative distribution function $L_{cf}(&amp;gt; X) = CR^{-D}$, if $X$ is given, how does one find the constant $C$ from a given data set?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, given this table:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/B5zDG.png&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/B5zDG.png&quot; alt=&quot;Source: C. Li et al. / Geomorphology 130 (2011)&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[Source: C. Li et al. / Geomorphology 130 (2011)]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;how does one determine how the values for $L_{cf}$ were obtained? It appears that they used the method of least squares fitting to obtain the values for $D$, but I don't seem to understand where the values for $C$ are coming from. Any help would be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="5778" LastActivityDate="2016-04-16T19:34:48.440" Title="How to determine constant $C$ in $p(x) = Cx^{-D}$?" Tags="|earthquakes|rainfall|statistics|natural-disasters|" AnswerCount="2" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7843" PostTypeId="2" ParentId="7841" CreationDate="2016-04-16T06:07:13.787" Score="3" Body="&lt;p&gt;C is purely empirical for any given situation. BEWARE of such equations! Using coefficients to six significant figures gives the &lt;em&gt;illusion&lt;/em&gt; of high precision when, in fact, the whole approach is extremely 'rubbery', and highly dependent upon the local geology / soil type / local hydrology. The expression is only valid for the location in which it was calibrated.&#xA;A small change in drainage can make a huge change in the equation so, personally, I think such stochastic simplifications of complex processes are not worth the paper they are written on! Intelligent eye-balling the potential landslide conditions, with a view to geology and drainage, may be just as good a guide as any (generally poorly calibrated) equation.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-04-16T06:07:13.787" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7844" PostTypeId="2" ParentId="7831" CreationDate="2016-04-16T06:28:07.227" Score="3" Body="&lt;p&gt;Any build up of static electricity in the ground will seek to connect with opposite charge in a storm cloud, and will spark through the line of least resistance. Any high metal structure, whether it is copper or not, is a candidate for the line of least electrical resistance. You may be able to protect your copper support by a higher lightning conductor (sharp spikey, high, pointing up, and well earthed, preferably to the local water table). Also bear in mind that the lightning can jump over short distances possibly to your copper support.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I once observed a lightning strike on a house close to where I live in South Australia. The lightning hit a TV aerial, jumped to the metal guttering around the roof, jumped to metal window frames, and made contact with the house's internal wiring. It was like a bomb had gone off. Every electrical appliance that was plugged in was fried. The guttering kind of exploded, and a sour smell of 'charred house' lingered for weeks. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So yes, you &lt;em&gt;should&lt;/em&gt; be concerned!&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-04-16T06:28:07.227" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7845" PostTypeId="2" ParentId="7814" CreationDate="2016-04-16T06:49:03.590" Score="2" Body="&lt;p&gt;Further to Pont's comments, there is often confusion about polar drift, which is two entirely different processes. The magnetic north pole is created by the rotation of the Earth's core, and possible differential rotation between core and mantle. This effect has historically shifted the magnetic north pole by about 50 km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The geographic north pole, which is the Earth's spin axis, has seen significant shift since the end of the last ice age, mainly due to melting of the North American ice cap. As N. America got 'lighter' the geographic north pole moved towards Hudson Bay. Now, with climate change Greenland is starting to melt so that the polar shift has changed direction - towards the UK in fact, but the total measured effect over the last few decades is only a few tens of metres. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-04-16T06:49:03.590" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7846" PostTypeId="1" AcceptedAnswerId="7851" CreationDate="2016-04-16T06:56:55.047" Score="12" ViewCount="1716" Body="&lt;p&gt;Snow is precipitation in the form of flakes of crystalline water ice that falls from clouds. Why is it not another colour?&lt;/p&gt;&#xA;" OwnerUserId="5798" LastEditorUserId="5798" LastEditDate="2016-11-26T05:05:35.590" LastActivityDate="2016-11-26T05:05:35.590" Title="Why snow is white?" Tags="|atmosphere|snow|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7847" PostTypeId="2" ParentId="7846" CreationDate="2016-04-16T07:38:43.660" Score="15" Body="&lt;p&gt;Snow has a very high albedo. Actually, it reflects all wavelengths of the visible spectrum, whilst absorbing no particular wavelength. Hence the eye averages out the multiple reflected wavelengths as 'white' - as is the case with most fine granular solids.   &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-04-16T07:38:43.660" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7849" PostTypeId="2" ParentId="7841" CreationDate="2016-04-16T19:34:48.440" Score="5" Body="&lt;p&gt;There are two solutions using the least square method for calculating $C$ and $D$. Both methods yield different results for your constants. There is no &lt;strong&gt;correct&lt;/strong&gt; method.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Method of least Squares&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;We define the least square error as follows:&#xA;$$\text{lse} = \sum_{i}{\left(y_i - f(x_i)\right)^2}$$&#xA;The $y_i$ and $x_i$ are our data through that we want to fit a function $f(x)$. The aim is to reduce our error $\text{lse}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The solution (minimal $\text{lse}$) for a linear function $f(x) = a \cdot x + b$ is described &lt;a href=&quot;https://en.wikipedia.org/wiki/Linear_least_squares_%28mathematics%29&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. The basic idea for calculating the minimum of $\text{lse}$ is to set $\partial \text{lse}/\partial a$ and $\partial \text{lse}/\partial b$ equal to $0$ and solve the resulting equation system to $a$ and $b$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Having said that we come to two solutions for calculating $C$ and $D$ in $f(x) = C\cdot x^{-D}$&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Solution 1: Logarithmize the Function&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;We rewrite&#xA;$$y_i = C \cdot x_i^{-D}$$&#xA;to&#xA;$$\ln{y_i} = \ln{\left(C \cdot x_i^{-D}\right)} = \ln{C} - D\cdot \ln{x_i} $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now we have a function of the form $\tilde{y_i} = a\cdot \tilde{x_i} + b$ with $\tilde{y_i} = \ln{y_i}$, $\tilde{x_i} = \ln{x_i}$, $a=-D$ and $b=\ln{C}$. Thus, we logarithmize our measured $x_i$ and $y_i$ values and put them into the formulas of the linear least square error method. From the resulting $a$ and $b$ we than calculate $D$ and $C$.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Solution 2: Insert the Function as it is&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;We set $f(x) = C\cdot x^{-D}$, insert it into our $\text{lse}$ formula:&#xA;$$ \text{lse} = \sum_i{\left(y_i - C\cdot x^{-D}\right)^2}$$&#xA;and minimize the resulting formula with respect to $C$ and $D$ for the given set of $x_i$ and $y_i$. This is a tricky and not as straight-forward as it is in the linear case. You could make $\partial \text{lse}/\partial C$ and $\partial \text{lse}/\partial D$ and look how far you come.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;I personally, prefer the answer of &lt;a href=&quot;https://earthscience.stackexchange.com/users/4507/gordon-stanger&quot;&gt;Gordon Stanger&lt;/a&gt; :-) .&lt;/p&gt;&#xA;" OwnerUserId="5594" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-04-16T19:34:48.440" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7851" PostTypeId="2" ParentId="7846" CreationDate="2016-04-17T00:12:05.250" Score="16" Body="&lt;p&gt;Normal ice (as in refrigerated ice cubes) mostly has uniform crystalline structure - water molecules are in a perfect hexagonal grid, which enables it to be transparent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not all ice is like that - for example, if you freeze water that contains tiny water bubbles due to a faucet aerator, the resulting ice would likely look white because the tiny air bubbles get frozen too, their edges forming multitudes of tiny prisms that produce all colours of the rainbow, averaged as white or bluish white.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Snowflakes are made of very fine structures of ice, thus also forming such prisms, also looking white as the result. Because their structure ranges widely, some snowflakes are more transparent than others, but almost all look white regardless. Snow is in fact semi-transparent too, easily evidenced when a thin layer of it covers a coloured surface, and also by shining some light through it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Under a good microscope, a small portion of a snowflake may look like a transparent ice structure, sporting rainbow colours on the edges. However as you zoom out, finer parts blur and start to look more white. Some snowflakes have more finer details and impurities that can be captured with average optical microscopes so they appear white even magnified.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;'White' colour itself is just how we describe achromatic (non-tinted) light. Further, human eyes adjust to lighting colour to treat it as white. If you project tinted light onto snow, it would of course look tinted. However, it may look less tinted than paper in similar conditions because snow tends to reflect light coming from every angle better.&lt;/p&gt;&#xA;" OwnerUserId="5809" LastActivityDate="2016-04-17T00:12:05.250" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7852" PostTypeId="2" ParentId="236" CreationDate="2016-04-17T18:28:41.793" Score="2" Body="&lt;p&gt;Strangely, the hypothesis (well supported) that Earth's rotation is slowing got its modern start from Immanuel Kant of all people ironically, who pointed out that tidal friction must be dissipative (we might presume by heat transfer) with geophysical consequence, which Kant claimed to be a lengthening of the day. His then novel idea was evidently supported by none other than Lord Kelvin. I am no physicist, but Earth's orbit has many nuances and influences, such as from other planets and its eccentricity, precession, axis motion in three dimensions and so forth. As the Sun burns away, it loses mass (extremely slowly) and all orbits increase, including the Moon's. So over a few billion years, a calculated effect of the role of any drift toward lunar tidal lock is exceedingly complicated. Perhaps a future supercomputed simulation will shed light on a model that is actually verifiable by physical measurements from a satellite (think ESA Hipparcos). Then we will know something about this question.&lt;/p&gt;&#xA;" OwnerUserId="5818" LastActivityDate="2016-04-17T18:28:41.793" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7854" PostTypeId="1" CreationDate="2016-04-17T21:29:45.987" Score="2" ViewCount="76" Body="&lt;p&gt;I have a dataset for river water, rain water and geology (main elements and trace elements). I want to apportion the contribution of geology to water chemistry using for that purpose a model. I was trying to use the Inverse model approach (Tarantola, 2005) but no clear definition is provided in the bibliographic sources (Gaillardet et al, 1999; Millot et al, 2003; Wu et al, 2005, Moon et al, 2007).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any ideas of how to apportion the river elements into different sources (reservoirs) and derive weathering rates as function of the geology (mainly igneous rocks: andesite and some rhyolites, eventually some carbonates) with the described information?&lt;/p&gt;&#xA;" OwnerUserId="5820" LastActivityDate="2016-04-17T21:29:45.987" Title="Inverse model problem" Tags="|geochemistry|models|inversion|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7855" PostTypeId="1" CreationDate="2016-04-18T11:02:03.473" Score="6" ViewCount="405" Body="&lt;p&gt;I already asked this on &lt;a href=&quot;https://astronomy.stackexchange.com/questions/14540/what-are-the-conditions-for-an-ionosphere-to-form&quot;&gt;Astronomy SE&lt;/a&gt; but did not receive any answer so far:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the prerequisites for an ionosphere to form?&lt;br&gt;&#xA;For example, can a planet without any atmosphere have an ionosphere?&lt;br&gt;&#xA;What about a planet that is very far from its sun, is there a point where the solar wind is too weak to create an ionosphere? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In one sentence, what are the conditions for an ionosphere to form on a given planet?&lt;/p&gt;&#xA;" OwnerUserId="5785" LastEditorUserId="-1" LastEditDate="2017-04-13T12:59:06.653" LastActivityDate="2018-10-20T21:05:52.437" Title="What are the conditions for an ionosphere to form?" Tags="|atmosphere|planetary-science|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="7856" PostTypeId="2" ParentId="7855" CreationDate="2016-04-18T20:54:49.087" Score="0" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Ionosphere#Geophysics&quot; rel=&quot;nofollow&quot;&gt;ionosphere - geophysics&lt;/a&gt; in short.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The ionosphere is a shell of electrons and electrically charged atoms&#xA;  and molecules that surrounds the Earth, stretching from a height of&#xA;  about 50 km (31 mi) to more than 1,000 km (620 mi). It owes its&#xA;  existence primarily to ultraviolet radiation from the Sun.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Thus there must be a source of gas that can form a plasma and a sun active enough to cause the atmosphere to ionize (hence the name) into a plasma. If there is no source of gas to ionize or not enough radiation to cause ionization, there will be no ionosphere.&lt;/p&gt;&#xA;" OwnerUserId="5008" LastActivityDate="2016-04-18T20:54:49.087" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7860" PostTypeId="1" CreationDate="2016-04-20T00:33:31.120" Score="10" ViewCount="455" Body="&lt;p&gt;Carbonate reefs usually appear as homogeneous bodies surrounded by sediment layers in seismic reflection data, but in the figure below the high amplitude reflection from the top of sediment (layer 2  at 0.3-0.34 seconds) is not horizontal yet the geological interface is horizontal.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone explain why? I appreciate any input, thanks.&lt;br&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/UJpCi.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UJpCi.png&quot; alt=&quot;Seismic profiles&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5840" LastEditorUserId="2536" LastEditDate="2017-06-11T12:16:15.417" LastActivityDate="2017-06-11T12:16:15.417" Title="Carbonate reef not horizontal in seismic section?" Tags="|geophysics|geology|seismology|carbonate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7861" PostTypeId="2" ParentId="7860" CreationDate="2016-04-20T02:29:17.387" Score="12" Body="&lt;p&gt;This phenomenom is called &lt;strong&gt;&lt;a href=&quot;http://www.glossary.oilfield.slb.com/en/Terms/p/pull_up.aspx&quot; rel=&quot;noreferrer&quot;&gt;velocity pull-up&lt;/a&gt;.&lt;/strong&gt; The seismic waves that reflected off the top of Layer 2 beneath the carbonate layer have also travelled through the carbonate. Because carbonate (at least in this case) has a faster P-velocity than the surrounding shale, waves that have travelled through the carbonate will return to the surface receivers in a shorter amount of time, relative to waves that only travelled through the shale. Thus the carbonate/Layer 2 interface appears at an earlier two-way-time relative to the Layer 3/Layer 2 shale interface. &lt;/p&gt;&#xA;" OwnerUserId="777" LastEditorUserId="28050" LastEditDate="2016-04-20T16:44:45.163" LastActivityDate="2016-04-20T16:44:45.163" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7862" PostTypeId="1" CreationDate="2016-04-20T03:34:52.350" Score="1" ViewCount="120" Body="&lt;p&gt;I found an outcrop of sandstone interbedded with claystone which strike/dip is N 195 E/42. Then, around 4 km at the south of previous outcrop, i found another outcrop with similar characteristic, but the strike/dip is N 132 E/79. The question is what should I do to make a cross section? should I connect the bed layer, considering their similar characteristic, or make a new layer, considering the distinct strike/dip? (could it be angular discontinuity?)&lt;/p&gt;&#xA;" OwnerUserId="5841" LastActivityDate="2016-12-16T17:18:00.000" Title="Structural geology, regarding cross section of two outcrops with similar characteristic but very distinct dip" Tags="|structural-geology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7863" PostTypeId="1" AcceptedAnswerId="7866" CreationDate="2016-04-20T08:47:27.347" Score="1" ViewCount="180" Body="&lt;p&gt;I know that there are many kinds of such caves, but I am looking for ones (if they exist, and I don't know) that contain stalagmite and stalactites and are located at high altitude inside a mountain. I also need to know in what kind of mountains they are, and what kind of rocks must be present. &#xA;Also, can you suggest me a reference book about the topic? &#xA;I know nearly nothing about geology.&lt;/p&gt;&#xA;" OwnerUserId="5842" LastActivityDate="2016-04-20T13:27:05.910" Title="At what altitude stalagmite/stalactite caves are located? What kind of rocks are needed to form them?" Tags="|geology|mountains|reference-request|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7864" PostTypeId="1" CreationDate="2016-04-20T09:06:59.997" Score="3" ViewCount="470" Body="&lt;p&gt;Why exactly does water cool down by evaporation? What happens in this process?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How much does it cool down? What's the formula to describe this process?&lt;/p&gt;&#xA;" OwnerUserId="4784" LastActivityDate="2016-04-20T13:47:03.297" Title="Cooling effect by evaporation" Tags="|meteorology|hydrology|water|water-vapour|evaporation|" AnswerCount="1" CommentCount="4" ClosedDate="2016-04-22T18:24:00.083" ContentLicense="CC BY-SA 3.0" />
  <row Id="7865" PostTypeId="2" ParentId="7855" CreationDate="2016-04-20T09:49:14.340" Score="3" Body="&lt;p&gt;Most of the visible matter in the universe consists of &lt;em&gt;ionized matter&lt;/em&gt; (I'm citing thise from the publicly available lectures from &lt;a href=&quot;http://farside.ph.utexas.edu/teaching/plasma/Plasma/index.html&quot; rel=&quot;nofollow&quot;&gt;R. Fitzpatrick&lt;/a&gt; and the monograph from J.A. Bittencourt - Introduction to plasma physics). This is true independent whether you measure it by mass or by number of atoms and molecules.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Why is this important?&lt;/strong&gt;&lt;br&gt;&#xA;As I see it the ionosphere is the part of the atmosphere that connects the electrically neutral atmosphere at high pressures and the low-pressure ionized regions of the universe.&lt;br&gt;&#xA;Thus, any planet will have firstly an ionisphere and secondly maybe an electrically neutral region that we call &quot;atmosphere&quot;. There is a caveat here, as the ionosphere doesn't have to be fully ionized, just have enough electrons and ions floating around to act as a plasma.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Why is gas ionized at low pressures?&lt;/strong&gt;&lt;br&gt;&#xA;The amount of ions that fly around in a certain volume is not only a function of the amount of freed electrons, but also of the amount of electrons that recombine.&lt;br&gt;&#xA;The strength of ionization will be a function of the process under consideration. However recombination will be independent of this and be governed by a $\sim n^2$-dependency on the density $n$.&lt;br&gt;&#xA;This will generally result in a disproportionally weak recombination as pressure / density decreases high up in the atmosphere. Or in other terms: At low pressures, you can get ionized thermally, by UV-photons, [...] but you don't find a partner anymore to recombine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Concluding&lt;/strong&gt;&#xA;I've presented a case why every planet must have an ionosphere. Details like the solar wind, distance from the star, it's class and atmospheric variables then control the shape of the entailing magnetosphere and exact height-profiles of ionized species.&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="489" LastEditDate="2016-04-20T12:48:40.370" LastActivityDate="2016-04-20T12:48:40.370" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7866" PostTypeId="2" ParentId="7863" CreationDate="2016-04-20T13:27:05.910" Score="3" Body="&lt;p&gt;The classic text has long been &quot;Karst Hydrology and Physical Speleology&quot; by Alfred Bogli, - which I highly recommend.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Karstic dissolution and precipitation (to form stalactites, helictites, etc.) are basically hydrologic processes in which groundwater seeks to attain thermodynamic equilibrium with the carbonate rocks with which it is in contact. Water flows downhill towards the base-level of erosion - generally sea level. But bear in mind that during the last glaciation sea level was about -120 metres compared to modern sea level. To get very high mountain karst the system has to develop and then be lofted by other tectonic processes of uplift. In the Jebel Akhdar of Oman there are caves up to about 2 km elevation, but I guess that some limestone massifs have been elevated higher than that.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-04-20T13:27:05.910" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7867" PostTypeId="2" ParentId="7864" CreationDate="2016-04-20T13:47:03.297" Score="3" Body="&lt;p&gt;Someone (Casey?) can probably provide a fuller answer, but the basic idea is that ice molecules are kind of locked into place by the molecular structure of the ice crystal, and can't vibrate very much. Increase the energy, and the molecules vibrate more until the molecular attraction is disrupted to become water, when they vibrate a lot. Increase the energy still further and the individual molecules are flying about like crazy, thereby turning into a gas. Water is an extraordinary compound. The energy required to break the attraction between molecules in the liquid state is a whopping 2258 kilo-joules per kilogram - a handy property that brought about the age of steam, and the industrial revolution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is this phase transition energy (latent heat) that produces the cooling. The principle of conservation of energy, as applied in nature, requires that to balance the energy gain by the water vapour, there has to be an equivalent energy loss somewhere - hence the cooling effect on the liquid.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-04-20T13:47:03.297" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7868" PostTypeId="2" ParentId="7862" CreationDate="2016-04-20T14:01:17.377" Score="2" Body="&lt;p&gt;Is this a homework question?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are quite steep dips, strongly implying that substantial deformation (folding) has taken place. The interlayering of steep mudstone pretty much rules out your outcrops as being original bedding structure. Draw your examples in plan, using the normal dip and strike notation. Sketch in some possible continuation of the strike (as curved lines). Then consider what style of folding could have created this pattern. Consider also the possibility that the fold could be steeply plunging.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you have an idea of the structure from the plan view, this should guide you in deciding the orientation of the cross section.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-04-20T14:01:17.377" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7871" PostTypeId="1" CreationDate="2016-04-20T21:18:37.177" Score="2" ViewCount="94" Body="&lt;p&gt;I've discovered that there's two different sets of data for earthquakes - one for actual number of earthquakes, and ones for only significant numbers of earthquakes. For example, in January 2016 the USGS showed 11 earthquakes of magnitude 6.0 or greater, of which 5 were listed as significant; in February 2016 it showed 9 such earthquakes of which 2 were listed as significant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I thought that this might explain why some people say that data shows that earthquakes are increasing, while others say the data shows that they are not. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I made a graph of the number of significant earthquakes of magnitude 6.0 and greater using USGS data for 2002 to 20015. There was a steady increase; for example, there were about 45 in 2007, 55 in 2011, 70 in 2014. I couldn't find any explanation for this, but I wondered if this increasing trend correlates to increasing population density in earthquake zones.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I couldn't find a set of historical data for actual (significant and insignificant) over the same period of time.&lt;/p&gt;&#xA;" OwnerUserId="5848" LastEditorUserId="725" LastEditDate="2016-04-20T21:23:10.247" LastActivityDate="2016-06-20T14:18:28.870" Title="Does the increasing number of significant earthquakes relate to increasing population density in earthquake zones?" Tags="|earthquakes|seismic-hazards|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7873" PostTypeId="1" CreationDate="2016-04-21T02:43:09.333" Score="2" ViewCount="128" Body="&lt;p&gt;I'm trying to help my 5th grade daughter with her science fair project.  She wants to test that water heats up more on a sunny day than a cloudy day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To help her, I'm trying to figure out how to block a lot visible light but allow IR and UV through.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know I could use smoke or dust, but can't figure out how to contain it for an experiment. &lt;/p&gt;&#xA;" OwnerUserId="5849" LastEditorDisplayName="user1161" LastEditDate="2017-06-12T22:53:12.393" LastActivityDate="2017-06-12T23:07:06.287" Title="How do simulate a cloudy day for a science fair project?" Tags="|meteorology|clouds|science-fair-project|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7874" PostTypeId="1" CreationDate="2016-04-21T10:48:25.857" Score="0" ViewCount="489" Body="&lt;p&gt;I wanted to know &lt;b&gt; what's is the intensity of terrestrial radiation?&lt;/b&gt; I mean the long wave radiation emitted by Earth &amp;amp; its atmosphere. As, I was differentiating between solar radiation and terrestrial radiation and intensity is the major thing to know when differentiating between these.&lt;/p&gt;&#xA;" OwnerUserId="5850" LastEditorUserId="6" LastEditDate="2016-04-22T14:55:31.410" LastActivityDate="2016-04-25T15:29:46.427" Title="What is the intensity of terrestrial radiation?" Tags="|atmospheric-radiation|" AnswerCount="2" CommentCount="11" ClosedDate="2016-05-10T13:24:22.870" ContentLicense="CC BY-SA 3.0" />
  <row Id="7875" PostTypeId="2" ParentId="7874" CreationDate="2016-04-21T12:20:08.327" Score="2" Body="&lt;p&gt;Assuming your question is about how much of the sun's radiation hits the Earth's surface rather than just reaching the edge of the atmosphere ...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The amount of solar radiation that hit's the Earth's surface varies a &lt;strong&gt;lot&lt;/strong&gt;, depending on weather conditions, time of day, day of the year, latitude, altitude, air quality ... It can be anywhere between 0 and ~$1200W/m^2$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a standard &quot;full sun&quot; solar intensity which is used as a benchmark for things like photovoltaics testing and calibration. That's $1000W/m^2$, with an atmospheric spectrum denoted by AM1.5&lt;/p&gt;&#xA;" OwnerUserId="100" LastActivityDate="2016-04-21T12:20:08.327" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7876" PostTypeId="2" ParentId="7871" CreationDate="2016-04-21T12:49:08.947" Score="1" Body="&lt;p&gt;The only possible linkage between moderate earthquakes and population is that more people create increased groundwater extraction, and hence near-surface fault planes tend to dry out. This effectively increases the friction so that there are less frequent but more violent quakes. However, this would only affect near-surface earthquakes which seldom exceed about magnitude 3 or 4. The really big earthquakes originate at plate tectonic interfaces at depths from about 10 km to hundreds of kilometres. There is nothing that humanity can do to influence processes on this scale. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another issue is that micro-seismicity occurs all the time - millions of small quakes that go un-noticed every year. Some of these can certainly be caused by humans - but does this really count? &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-04-21T12:49:08.947" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7879" PostTypeId="1" CreationDate="2016-04-21T19:13:54.087" Score="1" ViewCount="73" Body="&lt;p&gt;I've been challenged to think of some really out-of-the-box ways to locate people, and I had one. I'm 90% sure this isn't reasonably possible (probably only in laboratory settings), but I couldn't find a real answer to this question, so now I'm genuinely curious.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is possible to locate people's location by fluctuations in the Oxygen/Carbon Dioxide levels in the area (from people breathing)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I realize this is a really general question, and would depend on a ton of factors (size of the area, number of people, proximity of people to an appropriate sensor, etc). I'm really just looking for a general answer, but in case it helps, I'm referring to a general case of detecting people in outdoor settings (it would be part of a sensor suite that is outdoors and just trying to count/locate people in the general area).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even just a link to a technical paper that explains human impact on immediate area $\sf{O/CO_2}$ levels would be great - I've come up completely empty looking, everything I find just refers to global warming/overall environment/over thousands of years. Nothing for immediate impact, if there is any.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: This was marked as off-topic? Seriously? This is 100% earth science.&lt;/p&gt;&#xA;" OwnerUserId="5852" LastEditorUserId="5852" LastEditDate="2016-04-25T15:56:56.757" LastActivityDate="2016-04-25T15:56:56.757" Title="Locate people by Oxygen/Carbon Dioxide levels" Tags="|carbon-cycle|co2|oxygen|" AnswerCount="0" CommentCount="10" ClosedDate="2016-04-24T19:00:27.477" ContentLicense="CC BY-SA 3.0" />
  <row Id="7880" PostTypeId="2" ParentId="517" CreationDate="2016-04-22T07:06:18.587" Score="3" Body="&lt;p&gt;The previous answers are correct in that geophysics and crust-mantle samples are the main tools for sorting out the composition of the core. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition, don't forget that meteorites are the solid 'left overs' of planetary formation, and we have many thousands of meteorite analyses. Most are 'rocky', but some are palasites (mixed rock-iron), or 'irons', whose composition is basically iron with a smaller percentage of alloyed nickel and a few other heavy metals. Even allowing for the fact that average meteorite composition does not necessarily yield 'average Earth' composition, the presence of so much nickel-iron in meteorites is a strong pointer to the likely core composition of the Earth, and is entirely consistent with clues from geophysics. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="12057" LastEditDate="2018-01-31T02:44:50.697" LastActivityDate="2018-01-31T02:44:50.697" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7882" PostTypeId="1" CreationDate="2016-04-22T10:55:43.863" Score="8" ViewCount="1060" Body="&lt;p&gt;Recently an earthquake of magnitude 6.9 shook the northeastern region of India, where I live. After the earthquake, the climate has changed dramatically resulting in excessive hail showers, thunderstorms and heavy rain, continuously for 11 days until now. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is the time for the usual monsoon period, but the weather is quite unusual. Can an earthquake affect the weather; is this kind of behaviour a common after-effect?   &lt;/p&gt;&#xA;" OwnerUserId="5855" LastEditorUserId="28050" LastEditDate="2016-04-26T14:06:00.067" LastActivityDate="2019-05-17T10:21:57.523" Title="Can earthquakes affect the atmosphere?" Tags="|earthquakes|rainfall|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7883" PostTypeId="1" CreationDate="2016-04-22T13:24:36.660" Score="6" ViewCount="103" Body="&lt;p&gt;I need to design a weir for a small earth dam in an arid area with a small (smaller than 200 ha), fairly flat catchment area in southern Africa. The idea behind the dam is to collect not more than 10 000 cubic metres of water for small stock watering purposes for the immediate time after the rainy season, somewhat reducing the dependency on ground water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The challenge lies in applying the &quot;rational method&quot; (hydrology) where time of concentration is the determining factor to determine the peak flood. This method however was developed for larger catchment areas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there an alternative to the rational method for smaller catchments, or alternatively an adjusted methodology?&lt;/p&gt;&#xA;" OwnerUserId="5858" LastEditorUserId="10681" LastEditDate="2018-09-16T17:28:09.253" LastActivityDate="2018-09-16T17:28:09.253" Title="Is there a method to determine the point rainfall intensity for small catchments?" Tags="|hydrology|rainfall|runoff|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7885" PostTypeId="1" AcceptedAnswerId="13101" CreationDate="2016-04-22T19:46:40.193" Score="14" ViewCount="15377" Body="&lt;p&gt;If the Sahara used to be fertile and has since experienced minimal rainfall causing the current desert conditions, where did all the sand come from?&#xA;I assume the original dirt is still there, just underneath the sand.  &lt;/p&gt;&#xA;" OwnerUserId="5862" LastEditorUserId="20" LastEditDate="2016-04-22T21:54:03.543" LastActivityDate="2020-04-14T00:25:47.507" Title="Where did the sand in the Sahara come from?" Tags="|desert|" AnswerCount="6" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="7886" PostTypeId="2" ParentId="7874" CreationDate="2016-04-22T21:35:00.303" Score="1" Body="&lt;p&gt;Heat Flux from the earth is about 47 TW  +/- 2 TW&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Davies,J.H.,Davies,D.R.,2010.Earth’s surface heat flux.Solid Earth 1,5‐24.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A very detailed breakdown of the origin of the heat flux is in this paper. &lt;a href=&quot;http://arxiv.org/abs/1111.6099&quot; rel=&quot;nofollow&quot;&gt;http://arxiv.org/abs/1111.6099&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a discrepancy of about 20 TW that can't be completely explained by known or legacy heat sources within the earth. My father and I suggest in our book Terrestrial Nuclear Processes &lt;a href=&quot;http://www.createspace.com/3823397&quot; rel=&quot;nofollow&quot;&gt;http://www.createspace.com/3823397&lt;/a&gt; the discrepancy is possibly explained by low energy nuclear reactions in the crust and upper mantle.&lt;/p&gt;&#xA;" OwnerUserId="5612" LastEditorUserId="5612" LastEditDate="2016-04-25T15:29:46.427" LastActivityDate="2016-04-25T15:29:46.427" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7888" PostTypeId="1" AcceptedAnswerId="7890" CreationDate="2016-04-23T16:01:49.043" Score="15" ViewCount="13231" Body="&lt;p&gt;It's a simple question.. What do continents &quot;lay&quot; on? Do they float on water? or are they huge bodies that &quot;emerge&quot; from the sea floor/bed? are they connected to the bottom of the oceans?  Hope the question is clear. Don't be afraid to be thorough and scientific in your answer, I'll appreciate it and do everything to understand it. &lt;/p&gt;&#xA;" OwnerUserId="5769" LastEditorUserId="725" LastEditDate="2016-04-24T07:54:49.940" LastActivityDate="2018-02-11T02:21:33.527" Title="What do continents &quot;lay&quot; on?" Tags="|geology|plate-tectonics|mantle|crust|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7889" PostTypeId="2" ParentId="7888" CreationDate="2016-04-23T16:37:24.683" Score="-6" Body="&lt;p&gt;&lt;em&gt;[This answer has been highly critisized for using only the oversimplified descriptions used in school textbooks as an answer; the original answer is included only to make sense of the comments]&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(I'm not a professional geologist; this is from my personal studies) Lava, essentially. The Earth is molten when you get farther down, and the surface of the planet is made up of large plates of stone, which very slowly get pushed around by huge swirls of lava beneath them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that this is a very simplified explanation, but it seems to answer your question.&lt;/p&gt;&#xA;" OwnerUserId="5870" LastEditorUserId="5870" LastEditDate="2016-04-25T13:17:49.247" LastActivityDate="2016-04-25T13:17:49.247" CommentCount="16" ContentLicense="CC BY-SA 3.0" />
  <row Id="7890" PostTypeId="2" ParentId="7888" CreationDate="2016-04-23T17:00:10.887" Score="23" Body="&lt;p&gt;Matan, the continents where we all live &quot;float&quot; on the Earth's mantle. The continents are made out of relatively brittle rock called the &quot;Crust&quot; and the mantle is made out of much more ductile material. The mantle, however, is NOT liquid. It is just much more ductile than the crust so, in geologic time, it can flow (like silly putty). Also, the mantle is much more dense, so the crust doesn't sink into it by gravitational/bouyancy forces alone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tBBcO.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tBBcO.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Think of it as a creme brulee. We live on the little hard crust on the top. And there just happens to be a little bit of water on that crust that covers the less-elevated parts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, a little more technical, the crust that makes up the continents and the crust that is under the deep oceans are actually compositionally different. This is because the magma that solidifies to form each of these crusts travels, by &lt;a href=&quot;https://en.wikipedia.org/wiki/Partial_melting&quot; rel=&quot;noreferrer&quot;&gt;partially melting&lt;/a&gt; its way up, through different materials and different thicknesses. The consequence of this is that the crust making up the continents is less dense than that making up the bottom of the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AjwUC.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AjwUC.png&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The image above shows the process by which we get new (left) oceanic crust, (right) continental crust, and (middle) a special type of crust like that in Hawaii. Note that when &lt;a href=&quot;https://en.wikipedia.org/wiki/Convergent_boundary&quot; rel=&quot;noreferrer&quot;&gt;two tectonic plates collide&lt;/a&gt;, the more dense one will tend to subduct under the other.&lt;/p&gt;&#xA;" OwnerUserId="4636" LastActivityDate="2016-04-23T17:00:10.887" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7891" PostTypeId="1" CreationDate="2016-04-23T17:01:34.707" Score="1" ViewCount="58" Body="&lt;p&gt;I am trying to get into early-Earth geochemistry, and the cratons piqued my interest. They would need a very specific density to float, and the right heat resistance to not melt. What composition would the early cratons have?&lt;/p&gt;&#xA;" OwnerUserId="5870" LastEditorUserId="94" LastEditDate="2016-04-24T12:54:19.623" LastActivityDate="2016-04-24T12:54:19.623" Title="What composition would the early cratons have?" Tags="|geochemistry|earth-history|" AnswerCount="0" CommentCount="5" ClosedDate="2016-04-25T14:51:48.763" ContentLicense="CC BY-SA 3.0" />
  <row Id="7892" PostTypeId="1" AcceptedAnswerId="7895" CreationDate="2016-04-23T18:20:35.603" Score="4" ViewCount="1674" Body="&lt;p&gt;I just found &lt;a href=&quot;http://youtube.com/watch?v=ZkHp_nnU9DY&quot; rel=&quot;nofollow&quot;&gt;a video on sedimentary rock formation&lt;/a&gt;, and to my surprise, it stated that this only could occur in water! I always thought that any layer of matter, if buried deep underneath more matter, could form a sediment and become new rock. Am I completely wrong, or was the video simply not covering all bases?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I did Google it and check Wikipedia, but with my limited knowledge of the field, the results were inconclusive.&lt;/p&gt;&#xA;" OwnerUserId="5870" LastEditorUserId="28050" LastEditDate="2016-04-28T00:00:52.550" LastActivityDate="2019-11-09T21:24:00.810" Title="No sedimentation without water?" Tags="|sedimentology|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7893" PostTypeId="1" AcceptedAnswerId="7901" CreationDate="2016-04-23T23:02:41.607" Score="4" ViewCount="193" Body="&lt;p&gt;For the past 50 million years, India has been crashing into mainland Asia, creating the Himalayan range and uplifting Tibet, north of the mountains, to a current average height of 4500 meters above sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But why is Tibet the one getting an uplift? Why isn't India, instead?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastEditorUserId="4985" LastEditDate="2016-05-22T16:06:05.583" LastActivityDate="2016-05-24T10:01:02.300" Title="Shouldn't India Get an Uplift Too?" Tags="|plate-tectonics|mountain-building|tibetan-plateau|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7894" PostTypeId="1" AcceptedAnswerId="7914" CreationDate="2016-04-24T18:12:19.590" Score="3" ViewCount="1210" Body="&lt;p&gt;What is the economic importance of large meteorite impact craters with a diameter over 100 m? Can they form diamonds or produce other economic deposits? &lt;/p&gt;&#xA;" OwnerUserId="5551" LastEditorUserId="1242" LastEditDate="2017-05-25T01:12:19.037" LastActivityDate="2017-06-03T11:16:57.173" Title="Importance of meteorite impact craters in geology?" Tags="|geology|economic-geology|meteorite|diamond|" AnswerCount="4" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7895" PostTypeId="2" ParentId="7892" CreationDate="2016-04-25T14:04:50.057" Score="8" Body="&lt;p&gt;&lt;strong&gt;Not all sediments are deposited in water, but water is important in the formation of most sedimentary rocks.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we're just thinking about the deposition of the sediment, then we don't necessarily need water. Some counterexamples are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Eolianite&quot; rel=&quot;noreferrer&quot;&gt;&lt;strong&gt;Aeolian sandstones&lt;/strong&gt;&lt;/a&gt;, such as the Lower Permian Rotliegend sandstone of the North Sea. These are deposited by wind, not water.&lt;/li&gt;&#xA;&lt;li&gt;Some types of &lt;a href=&quot;https://en.wikipedia.org/wiki/Breccia&quot; rel=&quot;noreferrer&quot;&gt;&lt;strong&gt;sedimentary breccia&lt;/strong&gt;&lt;/a&gt;, which are chiefly deposited by gravity, not water.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Tuff&quot; rel=&quot;noreferrer&quot;&gt;&lt;strong&gt;Tuff&lt;/strong&gt;&lt;/a&gt;, which are deposited by gravity and wind, not water. They also undergo substantial compaction and lithification with or without water.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;But deposited sediment does not a rock make. Once deposited and if buried, most sediment undergoes compaction and diagenesis, eventually lithifying — a fancy word for turning into a rock. Below the water table, the shallow crust is saturated with (mostly) saline water, and processes like dissolution and cementation are necessarily aqueous. So it's fair to say that water is essential in the formation of sedimentary rocks, on Earth anyway.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Footnote&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;You were right to be skeptical, by the way; the video is introductory material apparently intended for grade school audience, so you can't treat it like a textbook. And you can't even take a textbook as 'truth', especially when it comes to slippery things like definitions. Sometimes generalizations and simplifications help, sometimes they don't.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2016-04-26T13:58:30.383" LastActivityDate="2016-04-26T13:58:30.383" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7896" PostTypeId="1" AcceptedAnswerId="7898" CreationDate="2016-04-25T14:38:52.333" Score="1" ViewCount="75" Body="&lt;p&gt;I have chemical analysis of one catchment which can be considered more or less homogeneous and also stream water analysis, I would like to know how elemental ratios (to Na for example) are related both in the geology and in the water. The rocks are mostly andesites. Can I expect the ratios to be similar, and based on your expertise can you recommend a methodology to relate both variables? &lt;/p&gt;&#xA;" OwnerUserId="5820" LastActivityDate="2016-05-01T23:35:02.200" Title="Elemental ratios in rocks and stream water" Tags="|geology|geochemistry|water|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7897" PostTypeId="1" CreationDate="2016-04-25T18:12:03.520" Score="1" ViewCount="798" Body="&lt;p&gt;My question concerns the following three hazards: earthquakes, hurricanes and drought.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of spatial extent (wide spread, limited), I believe that earthquakes generally have the most limited spatial extent of the three, followed by hurricanes. However, I am unsure about droughts. I assume that they have the largest spatial extent of the three, &lt;em&gt;but would anyone be able to give an explanation as to why?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regard to their predictability (hazard assessment), I would say that the order (from most predictable to least) would be:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Hurricanes &lt;/li&gt;&#xA;&lt;li&gt;Drought&lt;/li&gt;&#xA;&lt;li&gt;Earthquakes &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Hurricanes as past trends can be assessed and there are specific conditions that are required for a hurricane to form (e.g. between 5, 20 degrees from equator).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am less sure about prediction methods for droughts, but I assume that precipitation levels can be monitored, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lastly, I am aware that historic trends can be assessed for earthquakes and the general areas that will be affected can be predicted, however it is difficult to predict where the earthquake will occur along the fault line and the magnitude (I am aware that there are numerous questions on the predictability of earthquakes)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would love it if you could share your thoughts in terms of how you would order the hazards and why. &lt;/p&gt;&#xA;" OwnerUserId="5090" LastActivityDate="2016-04-26T00:15:37.723" Title="Spatial extent and predictability of various hazards." Tags="|earthquakes|tropical-cyclone|predictability|natural-disasters|drought|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7898" PostTypeId="2" ParentId="7896" CreationDate="2016-04-25T18:40:09.960" Score="4" Body="&lt;p&gt;There's no simple answer to this. The elemental ratios are a function of proximity to the ocean (Na, Cl, Br, I, etc), relative abundance and mode of weathering of feldspar, rate of weathering, rock Mg-Fe ratio and redox state (especially in relation to iron), the degree of rock mineralization (SO4, Cl, F), rock heterogeneity, and how close the rock-water system is to thermodynamic equilibrium.&#xA;There are many good books on the subject, of which my long-standing favorite is John Hem's classic US Geological Survey Water Supply Paper 2254, &lt;em&gt;Study and Interpretation of the Chemical Characteristics of Natural Water&lt;/em&gt;, 3rd Edition, &lt;a href=&quot;http://pubs.usgs.gov/wsp/wsp2254/pdf/wsp2254a.pdf&quot; rel=&quot;nofollow&quot;&gt;available online as a PDF&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="28050" LastEditDate="2016-05-01T23:35:02.200" LastActivityDate="2016-05-01T23:35:02.200" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7899" PostTypeId="2" ParentId="7897" CreationDate="2016-04-25T18:58:35.733" Score="1" Body="&lt;p&gt;One can't order these hazards without being much more precise. What energy threshold do you regard as an earthquake? There is micro-sismicity over most of ther planet for most of the time. The area affected deceases as the magnitude gets larger. And what do you regard as the spatial extent? The slippage footprint, or the area suffering some event magnitude? (difficult to define). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Likewise drought can be defined many different ways. Days without any rain? Days above a particular rain threshold? Days in which evapotranspiration exceeds precipitation? Days above a particular crop wilting point? Do you bring temperature into the equation? Moreover, in these days of climate change, falling water tables,and increasing frequency / intensity of El Nino, the area potentially affected by drought is evolving, so we need to be clear about the time period in our definition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The area potentially affected by hurricanes varies on each continent, and requires global climatic modelling to define. The oceanic area in which hurricanes can develop has been discussed previously in the Earth Science stack exchange, but the single most important factor is the area with a sea surface temperature of &gt;27 deg C. This is also a variable in these times of climate change.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-04-25T18:58:35.733" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7900" PostTypeId="2" ParentId="7894" CreationDate="2016-04-25T19:05:46.643" Score="2" Body="&lt;p&gt;Nowadays impact craters are of little significance. Back in the Hadean era of early planetary crust formation, bolide impacts were the defining process of planetary evolution.&#xA;As for diamonds, one might expect micro-diamonds to be formed in rare instances of carbon-rich impact craters. On the other hand, back in the days of early lunar exploration, some earth scientists expected abundant impact diamonds to be found on the moon's surface. They even tooled up a special laboratory to analyze diamonds brought back from the moon. Alas, none were found. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-04-25T19:05:46.643" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7901" PostTypeId="2" ParentId="7893" CreationDate="2016-04-25T19:17:42.747" Score="6" Body="&lt;p&gt;The simple answer is 'crustal thickness'. The two crustal plates of India and Eurasia are very different in character. The Indian plate is thin, the Eurasian plate is much thicker and more rigid. Both plates are so buoyant with respect to the underlying mantle that neither can subduct in the normal sense. But India is moving so fast that something has to give. The Indian plate is buckling a bit, but mostly being under=plated at low angle as the Eurasian plate rides over it - as it did is such spectacular fashion during last year's Nepalese earthquake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS the main continent-continent crunch occurred some 40 to 20 million years ago. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="28050" LastEditDate="2016-04-26T14:01:43.667" LastActivityDate="2016-04-26T14:01:43.667" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7902" PostTypeId="2" ParentId="7885" CreationDate="2016-04-25T19:55:06.600" Score="7" Body="&lt;p&gt;Minimum volumes of mobile sand can be estimated for each region of the Sahara, such as the 26 meter average thickness of the Erg Oriental of Algeria. Sand migration model conclusions regarding such volumes of sand are that the current Saharan dune distribution and morphology took at least 1.35 million years to evolve, possibly much longer if there were long periods of aeolian quiescence. Independent geological evidence indicates that cycles of wet and dry periods have occurred over the past 20 million years, corresponding respectively to semi-arid periods of erosion (in the source areas), and to periods of hyper-arid redistribution of sand. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-04-25T19:55:06.600" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7903" PostTypeId="1" CreationDate="2016-04-25T22:09:48.190" Score="2" ViewCount="213" Body="&lt;p&gt;What does the phrase &quot;spreading the risk&quot; mean with regards to risk assessment of natural hazards/disasters? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I came across the phrase in the World Economic Forum document, &lt;a href=&quot;http://www3.weforum.org/docs/WEF_VisionManagingNaturalDisaster_Proposal_2011.pdf&quot; rel=&quot;nofollow&quot;&gt;&lt;em&gt;A vision for managing natural disaster risk&lt;/em&gt;&lt;/a&gt;. A quote from the document:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;There are various options for risk management – avoidance, reduction,&#xA;  transfer or retention. Risk transfer is the underlying tenet for insurance&#xA;  markets, passing a liability onto another party (&lt;strong&gt;spreading the risk&lt;/strong&gt;). Risk pooling is vital to the recovery of individuals, firms and economies following a natural disaster.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;More specifically, what does the phrase mean with regards to insurance and aid, to reduce vulnerability to a disaster/hazard event?&lt;/p&gt;&#xA;" OwnerUserId="5090" LastEditorUserId="28050" LastEditDate="2016-04-25T23:05:46.677" LastActivityDate="2016-04-25T23:35:29.807" Title="What does the term spreading the risk mean, with regard to natural disasters?" Tags="|predictability|natural-disasters|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7904" PostTypeId="2" ParentId="7903" CreationDate="2016-04-25T23:34:15.927" Score="2" Body="&lt;p&gt;&lt;strong&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Insurance&quot; rel=&quot;nofollow&quot;&gt;Insurance&lt;/a&gt; may be the best example.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the document you linked to describes in some detail, there are lots of ways of spreading risk. Traditional insurance is one common mechanism. I think their point is that with a functional insurance model, the effects of a natural disaster may be less profound and/or less protracted (see page 27 of the report).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Think of risk as the possibility of something unpleasant happening &amp;mdash; say, something resulting in a financial cost. For example, there's a small risk of a hurricane destroying my house. I couldn't afford to rebuild it if that happened. So I buy indemnity cover for some small fixed monthly fee. Now there is essentially no risk to me, just a small definite cost. In effect, I have &lt;em&gt;transferred&lt;/em&gt; my risk to the insurer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The risk hasn't gone away. In exchange for my monthly fee, or &lt;em&gt;premium&lt;/em&gt;, the insurer has assumed the risk of having to pay me a lot of money at some point in the future. It has been pooled with lots of other people &amp;mdash; the insurer's other clients &amp;mdash; so there's also the grave risk of everyone claiming at the same time. Weighing these risks and setting the premiums accordingly is what insurance companies have to be really good at. Read up on the insurance consequences of the San Francisco earthquake, the September 11 attacks, or Hurricane Andrew.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2016-04-25T23:34:15.927" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7905" PostTypeId="2" ParentId="7903" CreationDate="2016-04-25T23:35:29.807" Score="2" Body="&lt;p&gt;Suppose you don't have your house insured. When natural disaster strikes your uninsured house, you are fully responsible for the costs in getting your house repaired. If you have a mortgage on your house, you are still liable for paying that mortgage even if the house is reduced to rubble. An insurance policy transfers some of that risk to the insurer. Now they are liable for paying for a share of the repairs should disaster strike, assuming the damage is covered by the policy. You still have the risk that disaster never will strike your house. In that case, you would have been better off not getting that insurance policy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Insurance works in part because it spreads the risk around amongst all of the policy holders, the vast majority of whom are are not struck by disaster. Insurance can leave the insurer holding a lot of risk. This is where the concept of reinsurance comes into play. Insurance companies take out insurance policy with reinsurance agents, thereby spreading the risk around even further.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2016-04-25T23:35:29.807" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7906" PostTypeId="2" ParentId="7897" CreationDate="2016-04-26T00:15:37.723" Score="2" Body="&lt;p&gt;Drought is not comparable to earthquakes and hurricanes because of the difference in time scale involved. We can generally consider earthquakes and hurricanes to be discrete events at a point in time. Drought, however, has a significant and variable time component. For example, you might consider a year of severely below average rainfall to be a drought but there are also multi-year droughts with prolonged periods of low rainfall. Descriptively, you can plot the average rainfall for an area along with the cumulative deviation from the average to see the trends. Even that should be used with caution - one year of very high rainfall may have a big effect on the deviation from the mean but won't really help rain-fed agriculture in subsequent low years. &lt;a href=&quot;http://www.livescience.com/21469-drought-definition.html&quot; rel=&quot;nofollow&quot;&gt;Here is a guide to the different definitions of drought&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The probability of a hurricane hitting the eastern United States in the next decade probably approaches 1.0 but to narrow that down to specific cities is more difficult. Once one has formed, the meteorologists are getting very good at predicting where it will make landfall. In between, the probability of a hurricane striking a particular city in a given year is low.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regards to earthquakes, there are many known faults where measurements indicate a high probability for a large earthquake. However, the timing may be within hundreds or thousands of years. We can predict where but not when.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are all different ways of looking at prediction that illustrate the considerations in how we think about 'prediction'. Ranking them is comparing apples to oranges.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2016-04-26T00:15:37.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7907" PostTypeId="2" ParentId="6724" CreationDate="2016-04-26T11:12:50.003" Score="3" Body="&lt;p&gt;There is no consensus, but educated opinions. I tend to think that they did not freeze over. Some interesting arguments are given by Dorian Abbot in his paper where he &lt;a href=&quot;http://geosci.uchicago.edu/~abbot/files/PAPERS/abbot-et-al-11.pdf&quot; rel=&quot;nofollow&quot;&gt;first published about the Jormungand model&lt;/a&gt;. I tend to think it's sensible to assume that since photosynthetic bacteria survived, there must have been some open water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact, I have a recent paper &lt;a href=&quot;http://www.oberlin.edu/math/faculty/walsh/RackauckasWalsh.pdf&quot; rel=&quot;nofollow&quot;&gt;where we show that under many generalization to Abbot's theory about the near-equator albedo&lt;/a&gt; (i.e. near the equator you have lower albedo to account for the lack of snow cover due to Hadley cells and other effects) you tend to get areas of open water, i.e. Jormungand models. Thus to me it seems that Snowball Earth is a good first approximation, while when one begins to add some details you tend to get at least some open water near the equator.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, more studies will need to be done to get anywhere near certainty.&lt;/p&gt;&#xA;" OwnerUserId="5746" LastActivityDate="2016-04-26T11:12:50.003" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7908" PostTypeId="1" AcceptedAnswerId="7909" CreationDate="2016-04-26T11:18:10.623" Score="6" ViewCount="435" Body="&lt;p&gt;The question arose when I heard from friends across many countries that March has never been so hot. I myself felt the same in my city (Bangalore, India). Then I tried searching on internet, and I found &lt;a href=&quot;http://climate.nasa.gov/news/2432/&quot;&gt;a link on NASA&lt;/a&gt;, which says March 2016 was indeed hot. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was wondering if experts can explain this rise in temperature? Is it due to higher $\ce{CO_2}$ levels due to human activity, or is it natural? Is it the start of unnatural global warming?&lt;/p&gt;&#xA;" OwnerUserId="5880" LastEditorUserId="28050" LastEditDate="2016-04-26T14:10:16.903" LastActivityDate="2016-04-28T09:07:21.990" Title="Above average global temperature in March 2016" Tags="|climate-change|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7909" PostTypeId="2" ParentId="7908" CreationDate="2016-04-26T12:48:34.443" Score="12" Body="&lt;p&gt;What happens in one city in one month is only a very very small part of the picture. You can make very little inference on global warming based on the weather in one city in one month.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can make a little more inference on global warming based on the weather around the world in one month.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And we can say a lot about global warming based on the world's weather over a 30-year period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A lot of heat got released from the ocean last year in the El Niño event: heat that had been accumulating in the oceans for a few years. That heat is now getting distributed around the world, which is why we're seeing rises in global surface temperatures - &lt;a href=&quot;http://www.climatecentral.org/news/comparing-el-nino-to-1997-19278&quot; rel=&quot;nofollow&quot;&gt;a similar thing happened back in 1997/8&lt;/a&gt;. The Earth has been accumulating a lot of heat for years, and it's now showing up as rises in surface temperatures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The accumulation of heat is happening because the Earth has been absorbing more energy than it has been radiating away into space. That has happened because of human emissions of greenhouse gases, in particular, but not exclusively, carbon dioxide and methane.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unnatural global warming started decades ago. Now, it's accelerating.&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="100" LastEditDate="2016-04-28T09:07:21.990" LastActivityDate="2016-04-28T09:07:21.990" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="7911" PostTypeId="1" AcceptedAnswerId="7912" CreationDate="2016-04-26T17:23:30.483" Score="5" ViewCount="150" Body="&lt;p&gt;Did large-scale sedimentation occur in any great amount during or soon after the Hadean/Archean period? Or did it only start later, because of the intense geological activity?&lt;/p&gt;&#xA;" OwnerUserId="5870" LastActivityDate="2016-04-28T00:05:05.010" Title="What is the earliest sedimentation we know of?" Tags="|sedimentology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7912" PostTypeId="2" ParentId="7911" CreationDate="2016-04-26T18:22:24.740" Score="9" Body="&lt;p&gt;&lt;strong&gt;The oldest known metasedimentary rocks are about 3.8 billion years old, formed in the Eoarchaean era.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;'Metasedimentary' just means they have been metamorphosed, so they started out as sediments. They are found in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Isua_Greenstone_Belt&quot; rel=&quot;nofollow&quot;&gt;Isua Greenstone Belt&lt;/a&gt; of southwestern Greenland. You can read about their discovery in Moorbath (2009). Quoting from there:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Published zircon dates strongly suggest that the depositional age of at least part of the [Isua supracrustal belt] could be closer to 3.8 Gyr than to 3.7 Gyr.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;According to the International Commission on Stratigraphy (Cohen et al. 2013), this puts them firmly in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Eoarchean&quot; rel=&quot;nofollow&quot;&gt;Eoarchaean era&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cohen, K, et al. (2013). The ICS International Chronostratigraphic Chart. &lt;em&gt;Episodes Journal of International Geoscience&lt;/em&gt; &lt;strong&gt;36&lt;/strong&gt; (3). &lt;a href=&quot;http://www.stratigraphy.org/ICSchart/Cohen2013_Episodes.pdf&quot; rel=&quot;nofollow&quot;&gt;Link to PDF.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Moorbath, S (2009). The discovery of the Earth's oldest rocks. &lt;em&gt;Notes and Records&lt;/em&gt; &lt;strong&gt;63&lt;/strong&gt; (4). &lt;a href=&quot;http://dx.doi.org/10.1098/rsnr.2009.0004&quot; rel=&quot;nofollow&quot;&gt;DOI: 10.1098/rsnr.2009.0004&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2016-04-28T00:05:05.010" LastActivityDate="2016-04-28T00:05:05.010" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7913" PostTypeId="1" CreationDate="2016-04-27T08:24:27.457" Score="9" ViewCount="506" Body="&lt;p&gt;How much of a risk does Mount Vesuvius pose for the population of the surrounding area?&lt;/p&gt;&#xA;" OwnerUserId="5889" LastEditorUserId="94" LastEditDate="2016-04-27T08:43:34.470" LastActivityDate="2021-09-17T08:30:37.003" Title="How big a risk is Mount Vesuvius for the local population?" Tags="|volcanology|volcanic-hazard|natural-disasters|" AnswerCount="1" CommentCount="4" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7914" PostTypeId="2" ParentId="7894" CreationDate="2016-04-27T22:36:48.447" Score="5" Body="&lt;p&gt;&lt;strong&gt;Impact diamonds&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, diamonds can form in meteorite impacts. For this several things need to happen:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;A meteorite of the correct size and velocity,&lt;/li&gt;&#xA;&lt;li&gt;The stuff it hits needs to contain carbon.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;If you have a meteorite hitting granite or ocean you're not going to get any diamonds. It usually has to hit something that has biogenic carbon (let's say peat, coal, graphite). Even then, the diamonds will &lt;a href=&quot;http://www.nature.com/ncomms/2016/160314/ncomms10970/full/ncomms10970.html&quot; rel=&quot;noreferrer&quot;&gt;form only&lt;/a&gt; in a very specific distance from ground zero, because there is a specific relation between pressure and temperature that has to hold. Pressure has to be high enough to stabilise diamonds, it has to be hot enough to break the graphite carbon bonds, but not too hot to destabilise diamond. This is why it also depends on the size and velocity of the meteorite - only some will make these unique conditions happen. A notable case is the &lt;a href=&quot;http://www.nature.com/articles/srep14702&quot; rel=&quot;noreferrer&quot;&gt;Popigai crater&lt;/a&gt; in Russia (that has some &lt;a href=&quot;http://dx.doi.org/10.1016/j.crte.2003.07.001&quot; rel=&quot;noreferrer&quot;&gt;weird&lt;/a&gt; stuff in it). Another case is the stuff &lt;a href=&quot;http://dx.doi.org/10.1016/j.pss.2013.05.003&quot; rel=&quot;noreferrer&quot;&gt;found&lt;/a&gt; in the peat around the Tunguska event.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, calling the material that forms &quot;diamond&quot; does not say much about what it's actually like. In some cases, it's not even proper diamond, but rather a carbon polymorph called &lt;a href=&quot;http://www.mindat.org/min-2431.html&quot; rel=&quot;noreferrer&quot;&gt;lonsdaleite&lt;/a&gt;, which is some kind of &quot;hexagonal diamond&quot; which has lower hardness than real diamond. Impact diamonds are also usually not pretty, so they're not suitable as gemstones in jewelry. If anything, they're useful as industrial diamonds. The thing is, that making industrial diamonds synthetically is much easier than digging them up from these locations. So, the answer is no. The economical significance of meteorite impact craters in relation to diamond formation is negligible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pretty diamonds usually form in Earth's mantle and are brought up to the surface in volcanic eruptions. They are mined from volcanic pipes such as kimberlites, and even though some of them are named like they're impact craters (like the &lt;a href=&quot;http://www.craterofdiamondsstatepark.com/&quot; rel=&quot;noreferrer&quot;&gt;Crater of Diamonds State Park&lt;/a&gt;) they are not actually impact craters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Other stuff&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is one notable occurrence of an impact crater that did cause economic mineralisation of something: the Sudbury Igneous Complex, or the Sudbury Basic, in Canada. In here, a meteorite impact caused melting of the crust and the formation of a nickel deposit. Currently, nickel, copper and some noble metals are mined from there. Even though it has been known for more than 100 years, only in the past 30 years or so the impact origin of it has been fully accepted.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-04-27T22:36:48.447" CommentCount="20" ContentLicense="CC BY-SA 3.0" />
  <row Id="7915" PostTypeId="1" CreationDate="2016-04-28T02:52:14.917" Score="5" ViewCount="101" Body="&lt;p&gt;I am asking because my Intro to Atmospheric Science class (lectures, labs, and the book) has not provided any practice examples of Skew-T diagrams, Coriolis force calculations, LCL (liquid condensation level) calculations, and 'What is wrong with this diagram?'-type problems.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I prefer that online, free resources be listed first.  If there are resources such as workbooks or lab manuals or subscription based services that are available, please list those afterwards.&lt;/p&gt;&#xA;" OwnerUserId="5896" LastEditorUserId="124" LastEditDate="2016-04-30T08:58:17.660" LastActivityDate="2016-04-30T08:58:17.660" Title="Are there any books, websites, etc. that have many practice problems for Skew-T diagrams and the atmospheric sciences in general?" Tags="|meteorology|homework|reference-request|radiosounding|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7917" PostTypeId="2" ParentId="7882" CreationDate="2016-04-28T14:32:54.677" Score="1" Body="&lt;p&gt;Apparently there is no relation of earthquakes with the weather. But in a book, &quot;Earthquakes- mitigation by Tatsch&quot; there are several precursors associated with ponding earthquakes. One is unusual weather. Some of these precursors are pre- and some post-earthquakes. Your cited earthquake may have some relation with it.&lt;/p&gt;&#xA;" OwnerUserId="935" LastActivityDate="2016-04-28T14:32:54.677" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7919" PostTypeId="1" AcceptedAnswerId="7922" CreationDate="2016-04-29T02:19:03.897" Score="7" ViewCount="1061" Body="&lt;p&gt;I've noticed on multiple occasions, that after heavy rainfall, the sun appears a pure glistening white, even if it's already standing low in the sky. I can't discount psycho-visual effects as an explanation, such as cloud shadows from above affecting color perception. Yet considering the many warm cloudy sunrises/sets I've seen, I'd be surprised if that's all there is to it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is anyone familiar with what I'm describing and knows of a scientific description of the phenomenon?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: I've gathered a few images which I think show what I'm seeing sometimes: &lt;a href=&quot;https://i.stack.imgur.com/46Dwa.jpg&quot; rel=&quot;noreferrer&quot;&gt;https://i.stack.imgur.com/46Dwa.jpg&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5903" LastEditorUserId="5903" LastEditDate="2016-04-29T02:35:55.763" LastActivityDate="2022-12-24T15:58:19.220" Title="The sun sometimes appears pure white after rainfall, how can this be explained?" Tags="|rainfall|sun|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7921" PostTypeId="1" AcceptedAnswerId="7968" CreationDate="2016-04-29T07:59:27.530" Score="2" ViewCount="409" Body="&lt;p&gt;Is there a specific temperature range that is considered to be the change from Continentality to Oceanity? Would this temperature change with latitude? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would be nice if someone could point me to some literature on the subject. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;" OwnerUserId="5905" LastActivityDate="2018-12-25T15:11:59.863" Title="Continentality/Oceanity" Tags="|climate|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7922" PostTypeId="2" ParentId="7919" CreationDate="2016-04-29T09:33:30.563" Score="6" Body="&lt;p&gt;When it rains the raindrops nucleate around aerosol particles of salt, dust, clay, soot, dimethyl sulphide, etc. In addition a falling raindrop may pick up any particulate matter that may be in its trajectory. The net result is that rain 'scrubs' the atmosphere clean. Without all these polluting particles to diffuse different wavelengths of the spectrum, the eye perceives the 'full spectrum', which the brain interprets as 'white light'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition, you are quite correct that the eye's response to light, and to what constitutes 'white light' is very variable, depending upon light intensity, extent of blue sky vs. cloud, direction relative to the sun, reflections from buildings, the sea, etc. and other factors. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="20" LastEditDate="2016-04-30T03:25:58.307" LastActivityDate="2016-04-30T03:25:58.307" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7923" PostTypeId="2" ParentId="7921" CreationDate="2016-04-29T09:41:41.450" Score="2" Body="&lt;p&gt;There is no such criterion. However, I'm sure one could devise one. For example, at any given location collect the differentials between daily maximum and minimum temperature. Average these differentials over each month and plot month vs mean differential temperature. Do this for many oceanic, continental and coastal locations. Plot the graphs, compare, and define your own criteria for different categories. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But why? What purpose would it serve?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-04-29T09:41:41.450" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7924" PostTypeId="1" AcceptedAnswerId="7925" CreationDate="2016-04-29T12:28:46.177" Score="1" ViewCount="155" Body="&lt;p&gt;What are all these gaps / circular structures found on a photo taken by Mars rover Curiosity at Dingo Gap? Have a look at &lt;a href=&quot;https://i.stack.imgur.com/cLWZ5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;the image&lt;/a&gt; I made to see what gaps I mean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/cLWZ5.png&quot; alt=&quot;dingo gap with explanation&quot;&gt;&#xA;(I know the quick paint job looks terrible)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see on the image I marked the area green where I found all these strange gaps. On the left I placed a zoomed view of the gaps, where I highlighted one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can find the &lt;a href=&quot;http://www.nasa.gov/sites/default/files/pia17766-figa_mastcam-sol526-wb-scalebars_0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;original picture on nasa.gov&lt;/a&gt;. Here is the &lt;a href=&quot;https://www.nasa.gov/jpl/msl/pia17766/&quot; rel=&quot;nofollow noreferrer&quot;&gt;accompanying article&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5906" LastEditorUserId="595" LastEditDate="2016-04-29T21:26:12.627" LastActivityDate="2016-04-29T21:26:12.627" Title="Strange circular structures found on a photo from Mars rover Curiosity at Dingo Gap" Tags="|structural-geology|mars|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7925" PostTypeId="2" ParentId="7924" CreationDate="2016-04-29T13:11:57.093" Score="8" Body="&lt;p&gt;There are no circles, it is an image artifact. &lt;a href=&quot;http://planetary.s3.amazonaws.com/assets/images/4-mars/2014/20140131_0528ML_panorama_valley-beyond-dingo-gap.jpg&quot;&gt;Here is another picture from Dingo Gap&lt;/a&gt; that shows nothing at the exact same position. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your mind is a well-trained pattern-matching machine that makes up patterns even when they are not actually there.&lt;br /&gt;&#xA;In other words &lt;em&gt;don't jump to conclusions&lt;/em&gt;. You are claiming that there are actual structures, which is one step too 'far'. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Credit: Emily Lakdawallah &lt;a href=&quot;http://www.planetary.org/blogs/emily-lakdawalla/2014/01311220-beautiful-view-into-dingo-gap-curiosity-528.html&quot;&gt;blog post&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="595" LastActivityDate="2016-04-29T13:11:57.093" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7926" PostTypeId="1" AcceptedAnswerId="7934" CreationDate="2016-04-29T13:50:18.703" Score="3" ViewCount="1178" Body="&lt;p&gt;I am extracting data from WRF model output for a specific area. The area I am extracting data for is 5000m above mean sea level. When plotting on a graph, I found that the dew point temperature is higher than the dry bulb temperature.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it possible that the dew point can go higher than the dry bulb? If yes, what is the inference of this phenomenon? Or can I simply assume that WRF could not calculate temperature values properly for this hill station?&lt;/p&gt;&#xA;" OwnerUserId="5473" LastEditorUserId="595" LastEditDate="2016-04-29T15:57:17.683" LastActivityDate="2016-05-08T01:52:03.477" Title="Can the dew point temperature be more than drybulb temperature?" Tags="|meteorology|wrf|" AnswerCount="2" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7927" PostTypeId="1" AcceptedAnswerId="7930" CreationDate="2016-04-29T16:44:21.917" Score="4" ViewCount="392" Body="&lt;p&gt;In a Chinese book, I read about the relationship between the numerical model spatial resolution and the computation cost.       &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It states: when the spatial resolution of model is finer, the result will be preciser. But to achieve a fine grid resolution, the computation cost will increase. For example, when the grid resolution in a 3-D model framework halves (e.g. from 10 km to 5 km), the computation cost will increase by a factor 24.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is this? How can I determine the increase of computation costs when the spatial grid resolution changes?&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Update&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;The model here is a 3-d numerical model for weather forcasting like WRF, MM5, etc.  &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Update 2&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Here is an schematic representation of the impact of model resolution&#xA;on the calculation of chemical oxidants&#xA;&lt;a href=&quot;https://i.stack.imgur.com/aGxoH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aGxoH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="595" LastEditDate="2016-04-30T08:50:18.493" LastActivityDate="2016-04-30T08:50:18.493" Title="Why does computation cost increase 24 times when the spatial resolution doubles?" Tags="|meteorology|atmosphere|atmosphere-modelling|wrf|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7928" PostTypeId="1" AcceptedAnswerId="7938" CreationDate="2016-04-30T01:28:17.137" Score="2" ViewCount="150" Body="&lt;p&gt;Are there any publicly available programs or source code for modelling global (or local) changes in sea level which include parameters for gravitational tidal effects?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have a physics background, and recently I started playing with large-scale fluid dynamics as a side project. The oceans and their boundary conditions are incredibly complicated, and I've gotten pretty far out of my depth at this point. I don't have the time or motivation to completely invent the wheel on this, so ideally, I'm looking for a program that would allow me to vary lots of parameters - including the tidal potential of the moon - and output topographical data for sea levels at different locations in the ocean or along the coast. However, I'd be happy with just an open source program that I could modify with additional parameters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm looking into this question predominantly from a hobbyist's &quot;toy model&quot; perspective. In particular, I'm curious about how oceanic tides would change with tidal forces, say, 100x greater than the moon's or with an almost tidally locked moon (e.g. six months between moonrise and moonset). How much land would be flooded with each high-tide and how much reclaimed with each low-tide? If anyone has an answer to that question, I'd be interested in hearing it as well.&lt;/p&gt;&#xA;" OwnerUserId="5908" LastEditorUserId="11908" LastEditDate="2019-03-17T19:43:55.153" LastActivityDate="2019-03-17T19:43:55.153" Title="Modelling sea levels with gravitational parameters" Tags="|oceanography|models|sea-level|tides|ocean-models|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7929" PostTypeId="1" CreationDate="2016-04-30T05:35:27.820" Score="5" ViewCount="5073" Body="&lt;p&gt;Natural rain water is slightly acidic (pH = 5.6) since there is carbon dioxide in the atmosphere that dissolves to make carbonic acid.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would be the pH of rainwater if carbon dioxide in the atmosphere was doubled to 800 ppm?&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-09-17T03:19:00.153" Title="What would the pH of rainwater be if carbon dioxide in the atmosphere doubled?" Tags="|atmosphere|co2|rain|acid-rain|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7930" PostTypeId="2" ParentId="7927" CreationDate="2016-04-30T07:46:26.060" Score="8" Body="&lt;p&gt;I can't answer why there's a 24x increase, according to the textbook - but it may well be the case for a specific model. In general,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you double the resolution of a 3D model in each dimension, you are multiplying the number of cells (or elements) in the model by $2^3 = 8$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Typically the maximum length of the time step that a model may be run at and remain stable is proportional to $\frac{\Delta x}{u}$, where $\Delta x$ is the size of a grid cell and $u$ is the speed of the flow in that cell (see info on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Courant%E2%80%93Friedrichs%E2%80%93Lewy_condition&quot;&gt;CFL condition&lt;/a&gt;) (for simplicity I'm assuming that the flow is parallel to one grid axis, which makes this one-dimensional; but the same result applies if not). This means that if you double the spatial resolution, you will probably also have to halve the timestep to maintain numerical stability. This gives an extra factor of two on the computation time, taking us to $2^4 = 16$ times.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This will vary in its details from model to model, and it is entirely feasible that additional non-linear processes in a given model push that to 24 times.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2016-04-30T07:46:26.060" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7931" PostTypeId="2" ParentId="7927" CreationDate="2016-04-30T08:08:44.547" Score="0" Body="&lt;p&gt;Further to Simon's answer, also bear in mind that it is not just the plan grid size that influences the computational time, it is also the number of interactive atmospheric layers in the model. Some of the more sophisticated global climatic models have about 30 vertical layers, adding massively to the number crunching time. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-04-30T08:08:44.547" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7932" PostTypeId="1" CreationDate="2016-04-30T08:31:02.567" Score="2" ViewCount="166" Body="&lt;p&gt;What is maximum temperature that can we have on earth on a single day?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I assume that after a certain limit, radiation and convection would start working strongly to have equilibrium of surroundings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to thermodynamics principles how high temp in theory can go before equalization process restrict any further increase?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Highest I found till now was 58 ℃&#xA;in Libya.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is theoretical question lets say an Air mass stays over an area and sun radiation is also highest how hot it can get&lt;/p&gt;&#xA;" OwnerUserId="5910" LastEditorUserId="5911" LastEditDate="2016-05-02T08:57:06.963" LastActivityDate="2016-05-02T08:57:06.963" Title="Maximum temperature possible on earth on a day" Tags="|meteorology|atmosphere|temperature|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7933" PostTypeId="2" ParentId="7932" CreationDate="2016-04-30T10:44:07.777" Score="5" Body="&lt;p&gt;Maximum temperature over what area? There are of course local hot spots at hydrothermal and volcanic centers which far exceed the generally excepted maximum recorded temperature, of 58 deg C in Libya (as you correctly state). Many other high temperature anomalous areas exist in areas where there are no met sites to record them. For example, in the Afar triangle depression in the horn of Africa, or in the foothills of the Jebel Akhdar in Oman. In the latter case the steep slopes of black harzburgite rock re-radiates high summer insolation to well into the 50s, but as far as I know, the maximum temperature has never been investigated. Then there is the time-scale. Global warming will almost certainly increase the maximum recorded temperatures over the coming decades and centuries. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the geological time scale, the sun's radiance is very slowly increasing, so it is only a matter of time (billions of years) before the planet gets so hot that photosynthesis will cease - in which case whatever humanity evolves into will eventually fry. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-04-30T10:44:07.777" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7934" PostTypeId="2" ParentId="7926" CreationDate="2016-04-30T15:31:24.703" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Dew_point&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dew point&lt;/a&gt; gives an indication of the moisture content of air; it is the temperature at which air can no longer hold water vapour.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following graph shows the relations of dew point to air temperature (dry bulb) for various levels of humidity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SblsI.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SblsI.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For humidity less than 100 percent, the air temperature is always higher than the dew point temperature and for a humidity of 100 percent air temperature equals the dew point temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://www.weatherquestions.com/What_is_dewpoint_temperature.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;dew point&lt;/a&gt; cannot be higher than the dry bulb temperature, it can only be lower of equal to it.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-04-30T15:31:24.703" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7935" PostTypeId="2" ParentId="7928" CreationDate="2016-04-30T16:54:00.853" Score="1" Body="&lt;p&gt;I can give this a shot.  Anyone smarter than me is welcome to offer corrections.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first issue, based on your question is how much closer you move the Moon.  (I'm assuming that you're not playing with other variations like the Earth's rotation speed or the Moon's mass).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want Tides to be 100 times greater, you have to move the Moon 10 times closer.  The tidal force is equal to the square of the distance (Radius to Radius, not surface to surface).   Putting the Moon 10 times closer would make it enormous in the sky and full moons would be bright enough to read by and the Tidal force would be 100 times greater.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Tidal Force is basically a bulge in the Earth that stays pointed at the Moon.  The land bulges too, not just the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Optimally, tides require about 1/4 of the circumference of the Earth to have full effect.  That's why lakes basically don't have tides.  Anything smaller than an ocean doesn't have tides to speak of.  Now if you make the tieds 10 times greater, the ratio ocean to large lake would still be the same, but large lake and sea tides (like the Mediterranean) would become much more apparent.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Think of tides as raising the sea level of the entire ocean.  Of-course, it's not really like that, but locally, that's essentially what happens.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the current tide is 50 CM (above average sea level), then imagine, in that area, what it would be like if sea level rose 50 meters.   In-land it wouldn't be an issue, but most coastal cities couldn't survive that.   100 times the tides would be the end of virtually all coastal living.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See chart.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zMw8S.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zMw8S.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Tide&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as nearly geostationary, that would have 2 effects.   The slower movement would create more leveling off, less variation that you see in the chart above, where one part of the Earth can get tides that are amplified can get 2 or 3 times the tides than average, and the Tides would happen more slowly, as you get two high tides every time the Moon is overhead.  If the Moon took 6 months between rises, you'd get a high tide every 3 months, but you'd still have the 50 foot tide problem.   The geostationary orbit distance of the Moon is pretty close to the first number given, about 36,000 km. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Currently Tides vary quite a bit, but that's because the Sun and Moon both interact with tides, so you get pretty significant tidal variation.  You also get variation as the Moon's distance to the Earth changes.   If the Moon was 10 times closer, the Sun-tides wouldn't change and would be arguably ignorable (less than 1/2 of 1% variation), where, currently the position of the sun to the Moon is important in tidal calculation.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You'd need to take into account the Moon's orbital period and the earth's rotation to estimate how quickly the tides move around the Earth.   Currently the Moon takes 29 days to orbit the Earth, so it's primarily the Earth's rotation (once every 24 hours) that governs the tides.   If you bring the Moon into 36,000 or 37,000 km, then the orbital speed is important because every few thousand KM would make a measurable difference. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My answer is pretty general.  I can try to touch on some specifics if I missed anything.  You could also ask in Astronomy stack exchange.  Tides are perhaps closer to Astronomy than Earth Science.  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Shouldn't the tidal forces go as the inverse cube of distance, not the&#xA;  inverse square? Given that and that orbit radius is the only change&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It's definitely the inverse square law.  I've done enough reading up on tidal forces to be sure of that.   The formula also clearly shows it as a product of inverse square too.  See &lt;a href=&quot;http://hyperphysics.phy-astr.gsu.edu/hbase/tide.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; or just google &quot;Tidal force formula&quot;. - Google's a handy shortcut for looking up formulas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I get what you're saying.  Thinking about it gets a little complicated.   This &lt;a href=&quot;http://milesmathis.com/tide.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;website&lt;/a&gt; gives a better explanation than I'm likely to.   As a rule of thumb, the tidal force is equal to the size of the object in the sky (distance from the center of the Earth, so near by objects don't count), times the density.   The Sun and Moon are about the same size in the sky, the Moon is more dense, so the Moon causes greater tides.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Shouldn't such a large change be partially damped by the resulting&#xA;  increase in basin volume as low-lying areas flood?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I hadn't thought of that, and probably, but I don't think that would affect it a great deal.  When a tidal bulge happens, the entire ocean (from the point of view of land) lifts up.  Oceans are very large, so unless the land is very flat for a very long distance, I don't think there's going to be a huge difference.   Lets say the tidal bulge peaks at 50 meters.  The tidal &quot;wavelength&quot; if you will is 10,000 km from peak to troth.  5,000 km from 50 meters to zero.  While it's a sign wave, not a linear drop, if we measure it linearly, which would be an exageration, the tidal bulge drops 1 meter every 100 km of distance.  Land usually rises quite a bit faster than that along the coastline almost everywhere.  There are some low-lands that would permanently become lakes, but mostly, I'd say at least 90%-95%, you can calculate how far the tide would reach based on meters above sea level.  If the land stays flat for a long time, you could adjust downwards.  That's my best guess anyway.   I'm not really an expert.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The bigger issue is the shape of the coastline.  Some coastlines focus the tide and effectively increase it.  The map above gives a pretty good estimate of that.  Basically, when the coastline is convex, the tide is focused and increases and when the coastline is concave, it decreases.  The exception being the gulf of Mexico, which has very low tides, despite being a very convex body of water, but the tides are blocked by Florida and many islands.   If you slow the orbit of the Moon down significantly, like you said, a moonrise every 6 months, then I think that effect would be largely reduced due to the much slower moving tide. It would have a lot more time to even out. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Could oceanic boundary conditions limit tides non-linearly? Might the&#xA;  increased tidal mass increase response time and flatten the bulge?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not crystal clear what you're asking here.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2016-05-01T00:52:54.667" LastActivityDate="2016-05-01T00:52:54.667" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="7936" PostTypeId="2" ParentId="6495" CreationDate="2016-04-30T22:39:39.653" Score="6" Body="&lt;p&gt;Prior to the &lt;em&gt;New Horizons&lt;/em&gt; flyby, a popular model for Pluto’s surface involved frost migration. &lt;a href=&quot;http://www2.ess.ucla.edu/~jewitt/papers/2006/DJ06.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Delsanti &amp;amp; Jewitt (2006)&lt;/a&gt; explain that at different points during the year, there should be seasonal pressure variations in the atmosphere. This then causes changes in the extent of nitrogen and methane ices on the surface, which over long periods of time - remember, Pluto has a very long period of revolution - alters local geography. The authors also mention &lt;a href=&quot;https://en.wikipedia.org/wiki/Cryovolcano&quot; rel=&quot;nofollow noreferrer&quot;&gt;cryovolcanism&lt;/a&gt; as a potential source for replenishment of methane that is destroyed by cosmic rays.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://arxiv.org/abs/1601.02833&quot; rel=&quot;nofollow noreferrer&quot;&gt;Trilling (2016)&lt;/a&gt; discusses cryovolcanism and two other processes as ways to resurface Pluto and remove craters:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Viscous relaxation.&lt;/strong&gt; Ices on the surface “flow”, removing certain surface formations.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Convective overturn.&lt;/strong&gt; Temperature differences in convective cells cause flows similar to those in viscous relaxation.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Cryovolcanism.&lt;/strong&gt; In addition to releasing methane (and potentially nitrogen), cryovolcanism can heat up parts of the surface, melting ices, which then erode features.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So far, &lt;a href=&quot;http://pluto.jhuapl.edu/News-Center/News-Article.php?page=20151109&quot; rel=&quot;nofollow noreferrer&quot;&gt;two cryovolcano candidates have been tentatively identified&lt;/a&gt;, Piccard Mons and Wright Mons:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ziz6e.png&quot; alt=&quot;&quot;&gt;&#xA;&lt;br&gt;&#xA;&lt;sup&gt;Image from &lt;a href=&quot;http://www.nature.com/news/icy-volcanoes-may-dot-pluto-s-surface-1.18756&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Nature&lt;/em&gt;&lt;/a&gt;; image credit NASA/SWRI/JHUAPL.&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cryovolcanic situation on Pluto may be closer to that of &lt;a href=&quot;https://en.wikipedia.org/wiki/Enceladus&quot; rel=&quot;nofollow noreferrer&quot;&gt;Enceladus&lt;/a&gt; than that of Europa. &lt;a href=&quot;https://en.wikipedia.org/wiki/Enceladus#South_polar_plumes&quot; rel=&quot;nofollow noreferrer&quot;&gt;Plumes&lt;/a&gt; were observed on Enceladus’s south pole by &lt;em&gt;Cassini&lt;/em&gt;, which appear to be cryovolcanic in nature:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:False_color_Cassini_image_of_jets_in_the_southern_hemisphere_of_Enceladus.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/8/86/False_color_Cassini_image_of_jets_in_the_southern_hemisphere_of_Enceladus.jpg&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&#xA;&lt;br&gt;&#xA;&lt;sup&gt;False color photograph of Enceladus’s south pole jets. Image in the public domain.&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tidal heating is thought to be a large contributor to the heat necessary to trigger the plumes. However, this is likely not enough. One explanation is &lt;a href=&quot;http://www.astrobio.net/topic/solar-system/saturn/enceladus/a-hot-start-on-enceladus/&quot; rel=&quot;nofollow noreferrer&quot;&gt;the hot start model&lt;/a&gt;, popular for many years, in which Enceladus initially generated enormous internal heat through the decay of radioactive isotopes of aluminum and iron. Other elements that are slower to decay could then have provided more heat as the aluminum and iron stopped producing heat. The subsurface ocean that may have resulted on Enceladus could also exist on Pluto, according to &lt;a href=&quot;https://www.researchgate.net/profile/Tilman_Spohn/publication/225019299_Subsurface_Oceans_and_Deep_Interiors_of_Medium-Sized_Outer_Planet_Satellites_and_Large_Trans-Neptunian_Objects/links/55018a3a0cf24cee39f7b952.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hussmann et al. (2006)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is only one possible explanation for a heat source to power cryovolcanism, but there does need to be some sub-surface process on both Enceladus and Pluto that can cause these effects. The hot start model is a good option.&lt;/p&gt;&#xA;" OwnerUserId="1399" LastEditorUserId="1399" LastEditDate="2016-05-02T00:19:06.027" LastActivityDate="2016-05-02T00:19:06.027" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7937" PostTypeId="1" CreationDate="2016-05-01T18:40:40.683" Score="2" ViewCount="92" Body="&lt;p&gt;Is there any way to convert the vehicular emissions from cars during journey to oxygen or safer gases to eliminate/decrease vehicular pollution?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is keeping in mind most populated and polluted countries where majority of people can't afford for/not willing to buy H&lt;sub&gt;2&lt;/sub&gt;-run cars nor get rid of existing fuel cars nor interested in using bicycles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In simple terms: Is there a possibility for real time  emission converter? Do they already exist or is there any research in this area? Any kind of help is appreciated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: re-posted at &lt;a href=&quot;https://sustainability.stackexchange.com/questions/6318/is-there-any-way-to-recycle-air-pollution-into-fertilizer&quot;&gt;Sustainablity&lt;/a&gt; &amp;amp; &lt;a href=&quot;https://engineering.stackexchange.com/questions/18461/is-there-any-method-to-recycle-air-pollution-into-fertilizer&quot;&gt;Engineering&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5915" LastEditorUserId="5594" LastEditDate="2017-12-14T10:10:45.157" LastActivityDate="2017-12-14T10:10:45.157" Title="vehicular pollution" Tags="|pollution|environmental-protection|air-pollution|" AnswerCount="0" CommentCount="7" ClosedDate="2016-05-02T08:53:37.413" ContentLicense="CC BY-SA 3.0" />
  <row Id="7938" PostTypeId="2" ParentId="7928" CreationDate="2016-05-02T12:26:20.807" Score="4" Body="&lt;p&gt;Starting from scratch and building a &quot;toy model&quot; is unlikely to be successful here, because while you could certainly model Newtonian tides, much of what happens on the continental shelves is tied very closely into the shapes of coastlines and bathymetry, the interaction between the inertia of the tidal wave and friction on the seabed, and so forth - a lot of non-linear effects, some of which are not fully understood.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My suggestion would be to start with an existing, validated, global ocean model and tweak its input parameters. For example, to simulate a change in the gravitational pull of the moon you could change the amplitudes of the lunar tidal constituents that drive the model (and perhaps also their periods, if you wanted to work out the appropriate orbital mechanics!).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Be aware that running models of this sort tends to be computationally expensive, obviously depending on the resolution - but it should be within the realms of what is feasible on a home computer, if you don't mind things taking a week or two to run (I assume, since this is a hobby project, that you don't have access to HPC resources for it). I'm not sure whether anybody makes a simple but validated model openly available - if anybody knows of one, perhaps they could comment. If not, you might have to build your own using an open source code, which would be substantially more work.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2016-05-02T12:26:20.807" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7939" PostTypeId="1" CreationDate="2016-05-02T14:04:53.777" Score="5" ViewCount="93" Body="&lt;p&gt;Of course atmospheric-ocean-coupled global climate models are, by their nature, very strong on ocean-atmosphere interaction, but what about large lakes? Lake Victoria in East Africa, the N American Great Lakes, and Lake Nasser, and maybe some others are of comparable size to the average grid cell size of the AO-GCM. Hence wind, humidity and evaporation should affect adjacent grid cells. Is this taken into account?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-09T19:26:03.430" Title="Are AO-GCMs sensitive enough to take large lakes into account?" Tags="|climate|climate-models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7941" PostTypeId="1" AcceptedAnswerId="7944" CreationDate="2016-05-02T18:54:00.527" Score="2" ViewCount="466" Body="&lt;p&gt;I live in the Reno/Sparks area and have started rockhounding.  One aspect I am quickly realizing is that many sites are actively being mined.  In order to avoid running afoul of local laws, I would like to get a map of active mining claims and potentially a map of expired claims.  Expired claims would be helpful for finding interesting sites.&lt;/p&gt;&#xA;" OwnerUserId="659" LastActivityDate="2022-07-18T19:50:10.940" Title="Where can I find a list of active mining claims in my area (Northern Nevada)?" Tags="|geology|mining|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7942" PostTypeId="2" ParentId="7941" CreationDate="2016-05-02T21:18:33.263" Score="-1" Body="&lt;p&gt;Obviously, an experienced rockhound would not be asking such a question; so my first points will be about safety.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;You definitely should not be in remote areas or around mines alone.&lt;/li&gt;&#xA;&lt;li&gt;You really want the buddy system when rock collecting.&lt;/li&gt;&#xA;&lt;li&gt;You also need proper safety gear.&lt;/li&gt;&#xA;&lt;li&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;If you are breaking rocks: then full sleeves, long pants and safety glasses (or goggles) are needed.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;You require soft iron hammers, not a hard steel hammer like you would use for nails.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;You should find a &lt;a href=&quot;http://www.cfmsinc.org/clubs/clubnv.htm#n005&quot; rel=&quot;nofollow noreferrer&quot;&gt;local rock and mineral club&lt;/a&gt; in your area; in that area, such a group would organize field trips. Often, clubs will allow members of other clubs to join the trip. The clubs would know where to collect specimens, and be able to show you such specimens, which would show you what you are looking for. Such trips would be organized in such a way that you could find out what sort of equipment that you require.&lt;/p&gt;&#xA;&lt;p&gt;Active mines will almost certainly turn you away. The mines that I've collected and that have had field trips do a massive clean-up before having a public collecting day, and only do so to try to create good will in the community. The insurance and liability problems are a nightmare for a mine.&lt;/p&gt;&#xA;&lt;p&gt;The USGS has posted various lists of mines with GPS coordinates. You can also get mineralogy maps and topological maps from them.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://minerals.usgs.gov/minerals/pubs/mapdata/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mine and Mineral Processing Plant Locations&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://mrdata.usgs.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS Mineral Resources On-line Spatial Data&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Offroading has a &lt;a href=&quot;http://offroadinghome.blogspot.com/2010/05/nevada-mine-map.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;webpage&lt;/a&gt; which has a spreadsheet with Nevada mine locations. (Click on title of article to download.)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://offroadinghome.com/nevada/nevada.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nevada Off Road ATV and SUV trail maps - Offroading Home&lt;/a&gt;&#xA;Overlays for Google Earth; the last two entries might be interesting.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://mrdata.usgs.gov/geology/state/state.php?state=NV&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS webpage&lt;/a&gt; with data for Nevada.&lt;/p&gt;&#xA;&lt;p&gt;List of &lt;a href=&quot;http://www.rockngem.com/ShowDatesFiles/ShowDatesDisplayAll.php?ShowState=NV&quot; rel=&quot;nofollow noreferrer&quot;&gt;rock and mineral shows&lt;/a&gt; in Nevada&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;The &lt;a href=&quot;http://www.renorockhounds.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reno Rock and Mineral Club&lt;/a&gt; is having its annual rock and mineral show this weekend. (May 7th and 8th,  2016.)&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;There are also books about rock collecting sites. For instance:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Rockhounding Nevada: A Guide to the State's Best Rockhounding Sites&#xA;By William A. Kappele &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/B005K8REOW&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;@Amazon&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="4685" LastEditorUserId="-1" LastEditDate="2022-07-18T19:50:10.940" LastActivityDate="2022-07-18T19:50:10.940" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="7944" PostTypeId="2" ParentId="7941" CreationDate="2016-05-03T00:23:33.233" Score="4" Body="&lt;p&gt;You may want to check this out ESRI open data &lt;a href=&quot;http://opendata.arcgis.com/&quot; rel=&quot;nofollow&quot;&gt;http://opendata.arcgis.com/&lt;/a&gt; if this is what you were looking for.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One another thing is that you might want to contact BLM's Nevada State Office.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.blm.gov/nv/st/en/prog/minerals/mining.html&quot; rel=&quot;nofollow&quot;&gt;http://www.blm.gov/nv/st/en/prog/minerals/mining.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They may have the data if they are on the Public lands. I am not sure about the private lands for that.&lt;/p&gt;&#xA;" OwnerUserId="5771" LastActivityDate="2016-05-03T00:23:33.233" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7945" PostTypeId="2" ParentId="448" CreationDate="2016-05-03T00:38:26.453" Score="2" Body="&lt;p&gt;&lt;sub&gt;Note: As I discovered after writing most of this answer, &lt;a href=&quot;https://space.stackexchange.com/questions/3115/is-cassini-equipped-for-detection-of-non-water-based-exobiology&quot;&gt;this question&lt;/a&gt; on Space Stack Exchange is closely related, and &lt;a href=&quot;https://space.stackexchange.com/a/3120/5963&quot;&gt;called2voyage’s answer&lt;/a&gt; uses some of the same early points that I do, as it discusses the paper you referenced.&lt;/p&gt;&#xA;&lt;p&gt;It’s worth noting that the results of McKay &amp;amp; Smith were purely theoretical, and their paper was originally received by the journal on the exact day the &lt;em&gt;Huygens&lt;/em&gt; lander reached Titan: January 14, 2005. The paper was revised that April, but data from the spacecraft does not appear to have been published prior to that date. In other words, the authors had no idea what &lt;em&gt;Cassini-Huygens&lt;/em&gt; would find on Titan. The empirical results confirmed their calculations; the “anomaly” you speak of had not yet been observed.&lt;/p&gt;&#xA;&lt;p&gt;Later that year, &lt;a href=&quot;http://www.nature.com/nature/journal/v438/n7069/full/nature04122.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Niemann et al.&lt;/a&gt; published results from the &lt;a href=&quot;http://attic.gsfc.nasa.gov/huygensgcms/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gas Chromatograph Mass Spectrometer (GCMS)&lt;/a&gt;. The results agreed with predictions of what Titan would look like with methanogenic life. Specifically, McKay &amp;amp; Smith stated that there would be three main observable effects:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;No acetylene (C&lt;sub&gt;2&lt;/sub&gt;H&lt;sub&gt;2&lt;/sub&gt;) on the surface&lt;/li&gt;&#xA;&lt;li&gt;Very low levels of ethane (C&lt;sub&gt;2&lt;/sub&gt;H&lt;sub&gt;6&lt;/sub&gt;) compared to the expected amounts from &lt;a href=&quot;https://en.wikipedia.org/wiki/Photodissociation&quot; rel=&quot;nofollow noreferrer&quot;&gt;photolysis&lt;/a&gt;. Photolysis on Titan has been studied by, among others, &lt;a href=&quot;http://www.lisa.univ-paris12.fr/%7Ejolly/Antoine%20JOLLY/romanzin2005.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Romanzin et al. (2005)&lt;/a&gt;, who include graphs of levels of ethane (and acetylene) at different altitudes.&lt;/li&gt;&#xA;&lt;li&gt;A “sink” of molecular hydrogen at the surface, leading to a non-zero change in concentration per change in altitude&#xA;Niemann et al. found only trace amounts of acetylene, low levels of ethane. They provide a description of the GCMS (better summaries are in &lt;a href=&quot;http://lasp.colorado.edu/%7Ehoranyi/graduate_seminar/GCMS.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this presentation&lt;/a&gt; and &lt;a href=&quot;http://www-personal.umich.edu/%7Eatreya/Proceds/1997_Gas_Chromatograph.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Niemann et al. (1999)&lt;/a&gt;); I’ll give a quick overview here.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Gas from the atmosphere enters the gas sampling system, where it is first moved through a &lt;a href=&quot;https://en.wikipedia.org/wiki/Gas_chromatography&quot; rel=&quot;nofollow noreferrer&quot;&gt;gas chromatographer&lt;/a&gt; (the carrier gas is hydrogen, chosen for storage efficiency), which separates gases using capillary columns. Gas is then sent through the ion source, which utilizes something called electron impact ionization, involving electron beams of 25 eV or 75 eV. A quadrupole switching lens can deflect the beams through mass filters; electron multipliers enhance detection in the low-mass regime.&lt;/p&gt;&#xA;&lt;p&gt;The GCMS also found slightly lower levels of H&lt;sub&gt;2&lt;/sub&gt; on the surface than higher in the atmosphere; however, this difference was within the limits of uncertainty and so is not at all conclusive. That said, the Ion and Neutral Mass Spectrometer (INMS) onboard the &lt;em&gt;Cassini&lt;/em&gt; orbiter did observe a gradient in the H&lt;sub&gt;2&lt;/sub&gt; mixing ratio. &lt;a href=&quot;http://web.archive.org/web/20120824195338/http://astrobiology.jhu.edu/wp-content/uploads/2010/06/Icarus-2010-Strobel.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Strobel (2010)&lt;/a&gt; viewed this in the interpretation of the gradient supporting the methanogenic predictions of McKay &amp;amp; Smith. The INMS, like the GCMS, uses an ion source and then directs the ions to a quadrupole mass analyzer; the two instruments are quite distinct, but they are still quite similar, so I’ll omit a description. A good overview can be found &lt;a href=&quot;http://lasp.colorado.edu/%7Ehoranyi/graduate_seminar/VortragINMS.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The predictions contained in the paper you cited contained three predictions, all of which have been verified. It is true that they can be explained through abiotic phenomena, as the authors have pointed out. However, the &lt;em&gt;Cassini-Huygens&lt;/em&gt; results mean that in order to conclusively prove that methanogenic life does not exist on Titan, other predictions would need to be falsified.&lt;/p&gt;&#xA;&lt;p&gt;One prediction involves an &lt;a href=&quot;https://en.wikipedia.org/wiki/Azotosome&quot; rel=&quot;nofollow noreferrer&quot;&gt;azotosome&lt;/a&gt;, a hypothetical analogue of a cell membrane composed of &lt;a href=&quot;https://en.wikipedia.org/wiki/Acrylonitrile&quot; rel=&quot;nofollow noreferrer&quot;&gt;acrylonitrile&lt;/a&gt; (created by &lt;a href=&quot;http://advances.sciencemag.org/content/1/1/e1400067.full&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stevenson et al. (2015)&lt;/a&gt;). It is considered one of the best hopes for the construction of cells in a world based around methane and ethane, like Titan. Assuming the stability of azotosomes - which Stevenson et al. consider over about 100 years - one barrier for this type of methanogenic life on Titan would be a lack of atmospheric acrylonitrile. However, the INMS confirmed previous detections of acrylonitrile (see &lt;a href=&quot;https://arxiv.org/ftp/arxiv/papers/1103/1103.0297.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nixon et al. (2010)&lt;/a&gt;). That said, concentrations would need to be high enough for life to be possible. More detailed mass spectroscopy on the surface, including samples from liquids, could answer this question.&lt;/p&gt;&#xA;&lt;p&gt;Another potential piece of evidence which McKay &amp;amp; Smith mentioned in passing is different levels of isotopes of carbon. Schulze-Makuch and Grinspoon (2005) note &lt;sup&gt;12&lt;/sup&gt;C/&lt;sup&gt;13&lt;/sup&gt;C ratios of 95.6 found by the INMS, which would be caused by lifeforms processing carbon-based compounds, but &lt;a href=&quot;http://lasp.colorado.edu/%7Eespoclass/5830_2013_Spring_homework/Atreya_TitansMethane_Cycle.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atreya et al. (2006)&lt;/a&gt; notes that this is only in the upper atmosphere; lower ratios (82.3, which is not drastically low but still too low) were found in the lower atmosphere. This would seem to be another strike against methanogenic life.&lt;/p&gt;&#xA;&lt;p&gt;Finally, as McKay wrote in &lt;a href=&quot;http://www.spacedaily.com/reports/Have_We_Discovered_Evidence_For_Life_On_Titan_999.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;an article in 2010&lt;/a&gt;, there are abiotic explanations for the discrepancy in molecular hydrogen:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The &lt;em&gt;Cassini-Huygens&lt;/em&gt; measurements are incorrect.&lt;/li&gt;&#xA;&lt;li&gt;H2&lt;/sub&gt; particles are being physically moved down in the atmosphere.&lt;/li&gt;&#xA;&lt;li&gt;There is a catalyst mediating a hydrogenation reaction. McKay writes that (referring to the existence of a catalyst operating at the low temperature of 95 Kelvin)&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;That would be quite interesting and a startling find although not as startling as the presence of life.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;In summary, there are quite a few different factors that could influence whether or not methanogenic life can exist on Titan:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A lack of acetylene would indicate the presence of methanogenic life.&lt;/li&gt;&#xA;&lt;li&gt;Low ethane levels could also be consistent.&lt;/li&gt;&#xA;&lt;li&gt;A vertical gradient of molecular hydrogen would indicate a “sink”, possible biotic in origin.&lt;/li&gt;&#xA;&lt;li&gt;The presence of high enough concentrations of acrylonitrile would indicate that life based on azotosomes is possible.&lt;/li&gt;&#xA;&lt;li&gt;High carbon isotopes ratios could be positive indicators of methanogenic life.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;em&gt;Cassini-Huygens&lt;/em&gt; covered all of these to some extent using the Gas Chromatograph Mass Spectrometer and the Ion and Neutral Mass Spectrometer. Follow-up measurements to confirm these results, likely using mass spectroscopy, would shed more light on the possibility for methanogenic life, while new instruments designed to detect McKay’s alternative hypothetical catalyst could show that there is no need for life to explain the &lt;em&gt;Cassini-Huygens&lt;/em&gt; measurements.&lt;/p&gt;&#xA;" OwnerUserId="1399" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-05-03T21:22:09.013" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7946" PostTypeId="1" CreationDate="2016-05-03T06:27:05.133" Score="1" ViewCount="120" Body="&lt;p&gt;Part of calibrating Global Climatic Models involves 'hindcasts' or 'history matching' against historic climate records, including rainfall. Such rainfall records are all in error because almost all raingauges incur at least a 7% aerodynamic under-catch. Conventionally this is not 'corrected' but for model calibration they should be corrected. So are GCM using corrected or uncorrected rainfall inputs? If yes, how are the rainfall records corrected - just multiplying by 1.07, or some other way? If no, why not? This is important because, worldwide, the GCM outputs are being used for forward projections of water resources (even though that is not what GCMs are designed to support).   &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-09T17:10:20.087" Title="When GCMs are calibrated do they use 'corrected rainfall' input?" Tags="|climate|models|water|rainfall|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7948" PostTypeId="1" CreationDate="2016-05-03T13:03:49.660" Score="6" ViewCount="505" Body="&lt;p&gt;I'm learning geology to understand the processes behind the formation of my local landscape. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand the processes behind big features, such as mountains. But I'm struggling to understand the processes behind small local features, such as hills.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I live in Reading, Berkshire, South-East England, with a typical landscape of &lt;strong&gt;rolling of grassy hills&lt;/strong&gt; and &lt;strong&gt;clay strata&lt;/strong&gt;. Similar to this image below.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What geological processes would be responsible for the formation of this landscape?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CYmtS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CYmtS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Additional Information&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Strata&lt;/strong&gt;: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I dug a hole in my garden and found there is a thin layer of soil, then a large amount of clay with a variety of rocks and pebbles. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1cQnh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1cQnh.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Features&lt;/strong&gt;: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main features are a landscape of rolling-hills and grassy plains. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What geologic processes are responsible for the formation of these low-hills and clay strata? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Were the hills once mountains, now eroded? &lt;/p&gt;&#xA;" OwnerUserId="5923" LastEditorDisplayName="user12525" LastEditDate="2019-08-27T11:18:28.303" LastActivityDate="2019-08-27T11:18:28.303" Title="The geology of local landscapes and small scale features" Tags="|geology|geomorphology|land-surface|mountain-building|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7949" PostTypeId="1" CreationDate="2016-05-03T15:51:33.583" Score="10" ViewCount="386" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon-14&quot;&gt;Carbon-14&lt;/a&gt; constantly forms in the atmosphere due to neutron capture by nitrogen-14 and subsequent emission of a proton. Other less frequent mechanisms involving neutron capture by carbon-13 or oxygen isotopes also exist, as well as radium decay, as the link explains.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: given an old (compared to the half-life of $\ce{^{14}C}$, more than 100 million years old let's say), sample of coal with for example 2% nitrogen and 80% carbon, how much carbon-14 would be present due to the neutron flux underground?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously this is going to be at least 1000 times less than in modern plant materials. But what order of magnitude would be expected?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In case it helps, I'll add these references:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/0168900294015279&quot;&gt;Background neutron flux determination at a depth of 3200 mwe underground&lt;/a&gt; &lt;em&gt;Nuclear Instruments and Methods in Physics Research A&lt;/em&gt; &lt;strong&gt;357&lt;/strong&gt; (1995), p 524-534.&lt;/li&gt;&#xA;&lt;li&gt;For shallower data: &lt;a href=&quot;http://www.radiochem.org/paper/JN92/jn9204.pdf&quot;&gt;Variation of Environmental Neutron Flux with the Depth of Water and Soil&lt;/a&gt; &lt;em&gt;Journal of Nuclear and Radiochemical Sciences&lt;/em&gt; &lt;strong&gt;9&lt;/strong&gt;, p 45-47.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="248" LastEditorUserId="28050" LastEditDate="2016-05-03T17:32:59.000" LastActivityDate="2016-09-23T00:30:57.607" Title="Rate of underground formation of carbon-14 by neutron capture" Tags="|geology|radioactivity|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7951" PostTypeId="2" ParentId="324" CreationDate="2016-05-04T01:05:24.980" Score="0" Body="&lt;p&gt;Why couldn't &quot;evaporation&quot; be a possibility here?  We usually think of many igneous crystals forming during the cooling of magma, but evaporation too is a cooling process, we know.  So if these molecules know how to arrange themselves from being in liquid form with say a wall of points growing out of a milky quartz matrix, for instance, why couldn't a much gentler and slower process of cooling happen with minerals suspended in water?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Back in the early 90s I spend a couple of days mining quartz points near Mt. Ida, Arkansas.  I mostly worked on a single vein with two facing walls of large, optical-quality points growing toward one another. In between the two facing walls was packed about 6-8&quot; that had filled in with a dense, rubbery red clay that had obviously settled into the vein over many many years and dried out.  Suspended in that red clay at various points were, not double-terminated points, but tabular crystals that were not touching either wall of the vein, but had been apparently floating in their as it filled with clay-particle sediment.  I have always wondered how they formed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for the previous comments.  I like the idea of a tiny nucleus begining the expansive growth into a double-termination, by contrast with the broad cooling of a wall of points, etc.&lt;/p&gt;&#xA;" OwnerUserId="5931" LastActivityDate="2016-05-04T01:05:24.980" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7952" PostTypeId="2" ParentId="3036" CreationDate="2016-05-04T09:38:12.330" Score="4" Body="&lt;p&gt;The oldest (fairly) definitive fossils date from about 3.48 billion years ago (Ga) and consist of sedimentary structures associated with microbial mats living in coastal environments.&lt;sup&gt;[1]&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Beyond this there are is no known direct fossil evidence so instead we have to rely on geochemical evidence. As the OP mentioned, the oldest known sedimentary rock, the Isua greenstones, are dated to 3.8 Ga and contain isotopically light graphite which may indicate a biogenic origin, although this is hotly disputed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recently another paper has pushed the date for potentially biogenic carbon back even earlier to 4.1 Ga.&lt;sup&gt;[2]&lt;/sup&gt; The authors analysed 10,000 zircons from the Jack Hills metasediments from Western Australia and managed to extract one which was uncracked and contained what they believe to be primary, isotopically closed graphite inculsions. The zircon has been dated by U-Pb dating to 4.10 ± 0.01 Ga and so the graphite inclusions must be at least as old as this. Isotopic analysis was done on the carbon and the δ&lt;sup&gt;13&lt;/sup&gt;C value comes out at −24 ± 5‰. This is consistent with carbon which has undergone isotopic fractionation by enzymatic carbon fixation, which has an average value of δ&lt;sup&gt;13&lt;/sup&gt;C = -25‰ over the past 3.5 Ga. Therefore the 4.1 Ga graphite &lt;em&gt;may&lt;/em&gt; be evidence of biological activity at this very early stage in Earth's history.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1] &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3870916/&quot; rel=&quot;nofollow&quot;&gt;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3870916/&lt;/a&gt; &lt;br&gt;&#xA;[2] &lt;a href=&quot;http://www.pnas.org/content/112/47/14518.full.pdf&quot; rel=&quot;nofollow&quot;&gt;http://www.pnas.org/content/112/47/14518.full.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2016-05-04T09:38:12.330" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7953" PostTypeId="2" ParentId="7948" CreationDate="2016-05-05T13:00:48.160" Score="2" Body="&lt;p&gt;(this is consciously the start of the answer - my regional geology books -cf. above comment, are packed away due to a house move).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rolling hills are very distinctive of the English Jurassic &amp;amp; Cretaceous. Relatively low dipping rocks - long wavelength folds. The ridges are due to rocks that are more resistant to erosion. For example, the English chalk forms the North Downs and South Downs (and the Yorkshire &amp;amp; Lincolnshire Wolds). Chalk is actually more resistant to erosion that some of the surrounding rocks (don't believe me? Have a look at Beachy Head or Flamborough Point!).  These ridges have influenced pre-Roman history - eg. the Ridgeway follows a series of these ridges.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I may be out of date on this, but the folding is usually blamed on the formation of the Alps. The Alps are a long way off, but their influence can be felt as mild folding. The cause must be after the youngest Cretaceous that is present (which I think is the chalk?) - and there was only really the Alps, the Paleogene North Atlantic Volcanism (eg. Skye, Arran, Mull), and opening of the North Atlantic to choose from.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for your soils: This is where the Regional guide will help. The soils are much more recent. A decent explanation will probably involve at least one ice age, and river courses which have since changed (eg. the proto-Thames used to flow from the North!)&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2016-05-05T13:00:48.160" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7954" PostTypeId="1" CreationDate="2016-05-06T02:05:32.337" Score="6" ViewCount="1172" Body="&lt;p&gt;I am building an open source spatial geochemical/geological observational database for mineral exploration.  I need to fill the mineral lookup table.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where can I find a complete list of all minerals and mineral-groups, chemical formula, Strunz and/or Dana number, or any other data.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want the Strunz and/or Dana numbers so I can query the data and recode the data based upon mineral groups.&lt;/p&gt;&#xA;" OwnerUserId="5940" LastEditorUserId="725" LastEditDate="2016-05-06T08:29:11.547" LastActivityDate="2021-01-28T00:51:21.777" Title="Looking for a complete table of minerals for a database" Tags="|geology|geochemistry|mineralogy|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="7956" PostTypeId="1" CreationDate="2016-05-06T14:16:58.133" Score="5" ViewCount="1894" Body="&lt;p&gt;How much of the ice on Earth is floating (such as icebergs, or perhaps all the ice up at the North Pole)? &lt;/p&gt;&#xA;" OwnerUserId="5942" LastEditorUserId="124" LastEditDate="2016-05-07T22:05:21.227" LastActivityDate="2016-05-09T11:37:14.713" Title="How much of the ice on earth is floating?" Tags="|ice-sheets|ice|cryosphere|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7957" PostTypeId="1" CreationDate="2016-05-06T15:40:22.793" Score="4" ViewCount="51" Body="&lt;p&gt;The most famous equation describing the permeability $k$ of a soil is the Kozeny-Carman equation:&#xA;$$k = \frac{\phi}{8}r^2 \approx \frac{\phi}{c}\left(\frac{V}{S}\right)^2$$&#xA;$\phi$: porosity&lt;br&gt;&#xA;V: pore volume&lt;br&gt;&#xA;S: specific surface area&lt;br&gt;&#xA;$c$: constant&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another equation that describe the permeability $k$ is the Schlumberger-Doll Research (SDR) equation:&#xA;$$k = c_\mathrm{SDR}\phi^a T_2^b$$&#xA;$\phi$: porosity&lt;br&gt;&#xA;T$_2$: Caracteristic decay time&lt;br&gt;&#xA;$a$, $b$, $c_\mathrm{SDR}$: constants&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The latter equation has been derived from the former and I tried do redo the derivation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Knowing that:&#xA;$$T_2^{-1} \approx \rho_2 \frac{S}{V}$$&#xA;$$\Leftrightarrow T_2 = \frac{1}{\rho_s}\frac{V}{S}$$&#xA;$\rho_s$: surface relaxivity&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Inserting in the SDR equation:&#xA;$$k = c_\mathrm{SDR}\phi^a\left(\frac{1}{\rho_s}\frac{V}{S}\right)^b = c_\mathrm{SDR}\phi^a\frac{1}{\rho_s^b}\left(\frac{V}{S}\right)^b$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Comparing this equation to the right side of the Kozeny-Carman equation I obtain:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\phi = \phi^a \Leftrightarrow a = 1$$&#xA;$$\left(\frac{V}{S}\right)^2 = \left(\frac{V}{S}\right)^b \Leftrightarrow b=2$$&#xA;$$\frac{1}{c} = \frac{c_\mathrm{SDR}}{\rho_s^b} \Leftrightarrow c = \frac{\rho_s^2}{c_\mathrm{SDR}}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I get a=1 and b=2 what is not in accordance with the exponent of 4 mentioned in this site &lt;a href=&quot;http://petrowiki.org/Permeability_estimation_with_NMR_logging&quot; rel=&quot;nofollow&quot;&gt;petrowiki.org&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Both models treat permeability as an exponential function of porosity, $\phi^4$.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Can somebody explain me how they get an exponent 4 and not 1 for $\phi$ ?&lt;/p&gt;&#xA;" OwnerUserId="5943" LastEditorUserId="28050" LastEditDate="2016-05-06T16:44:37.727" LastActivityDate="2016-05-06T16:44:37.727" Title="Link between different ways of modeling permeability" Tags="|rocks|fluid-dynamics|hydrogeology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7958" PostTypeId="1" AcceptedAnswerId="7967" CreationDate="2016-05-06T16:32:25.383" Score="2" ViewCount="528" Body="&lt;p&gt;I am using a API to get historical weather information, only it is missing the probably and intensity of rain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do have this data:  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;cloudCover&lt;/li&gt;&#xA;&lt;li&gt;pressure&lt;/li&gt;&#xA;&lt;li&gt;dewPoint&lt;/li&gt;&#xA;&lt;li&gt;humidity&lt;/li&gt;&#xA;&lt;li&gt;temperature&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Is there a way to approximate the probability and or intensity of rain based on just the above.&lt;/p&gt;&#xA;" OwnerUserId="5944" LastActivityDate="2016-05-07T18:29:59.120" Title="Is there a way to guess if its going to rain based on pressure temperature humidity and cloud cover" Tags="|meteorology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7960" PostTypeId="1" CreationDate="2016-05-07T00:53:09.297" Score="3" ViewCount="7309" Body="&lt;p&gt;This question popped up in my head while watching LOTR, in wich a tree says: going south always feels like going down.&lt;/p&gt;&#xA;" OwnerUserId="5945" LastEditorUserId="39" LastEditDate="2016-05-08T06:23:56.833" LastActivityDate="2022-09-26T22:27:34.733" Title="Why is the north considered as up, and south as down?" Tags="|cartography|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="7961" PostTypeId="2" ParentId="7960" CreationDate="2016-05-07T01:39:51.800" Score="4" Body="&lt;p&gt;There is no good reason. It's simply a convention that someone started a long time ago and that stuck. Like the question whether an hour is divided into 60 minutes and a minute into 60 seconds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you go to Australia, you will find plenty of maps for tourists that show Australia at the top and Europe at the bottom.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2016-05-07T01:39:51.800" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7962" PostTypeId="2" ParentId="7956" CreationDate="2016-05-07T10:46:35.757" Score="0" Body="&lt;p&gt;The Antarctic land ice averages a little over 1.8 kilometres thick. Greenland  ice averages a bit more than 2 kilometres thick. The circum-Antarctic ice thickness averages only between 1 and 2 metres in thickness, whilst the Arctic (all sea ice) varies between 1 and 5 metres thick - it was &gt;6 metres thick but global warming has been thinning the ice in recent decades.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At its maximum winter extents the sea ice is comparable in area to the continental ice, so the fraction of global floating ice is about 0.1%. If you need a more accurate answer then I suggest you trawl the internet for areal extents, and do a seasonal mass balance. Obviously, it will vary according to which hemispheric winter you choose. &#xA;I suggest 'Arctic Sea Ice News' &lt;a href=&quot;https://nsidc.org/arcticseaicenews/&quot; rel=&quot;nofollow&quot;&gt;https://nsidc.org/arcticseaicenews/&lt;/a&gt; as a good starting point.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-05-07T10:46:35.757" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7964" PostTypeId="2" ParentId="7956" CreationDate="2016-05-07T11:18:27.140" Score="7" Body="&lt;p&gt;&lt;strong&gt;A first-order estimate is about 5%.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a trickier question than it first appears because of ice shelves. Quoting from Kusky (2014):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Ice shelves form where ice sheets move over ocean waters and form a thick sheet of ice floating on the water and attached to the land on one, two, or three sides. Their seaward sides are typically marked by a steep cliff up to 1500 ft (500 m) high, where many glaciers calve off from forming icebergs.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So they are floating, and they can be up to 2000 m thick, according to &lt;a href=&quot;http://www.antarcticglaciers.org/glaciers-and-climate/shrinking-ice-shelves/ice-shelves/&quot; rel=&quot;nofollow&quot;&gt;antacticglaciers.org&lt;/a&gt;. So they definitely make a substantial contribution to the world's sea ice fraction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Continuing with Kusky:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Ice shelves are found in Antarctica, Greenland, and along the polar seacoasts of the Canadian Arctic Islands. The largest ice shelves are contained in Antarctica, which contains 91% of the world's glacial ice, around 7% of which is contained in ice shelves. These ice shelves cover 50% of the coast of Antarctica, forming an area 1/10th the size of the continent.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;If you don't take ice shelves into account, and only think about pack ice, you end up with about 0%, because &lt;a href=&quot;https://en.wikipedia.org/wiki/Arctic_ice_pack&quot; rel=&quot;nofollow&quot;&gt;pack ice&lt;/a&gt; is generally thinner than about 4 m, and so makes up a tiny fraction of global ice volume, in spite of its extensive area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But if you do account for ice shelves, especially &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_Antarctic_ice_shelves&quot; rel=&quot;nofollow&quot;&gt;the southern ones&lt;/a&gt;, the answer must be much greater. I have not done the research to find the numbers, but the text I quoted suggests something less than 7%, so I'm going with 5% as a first-order, round-number guess.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kusky, T M (2014), Encyclopedia of Earth Science, New York Academy of Sciences, 529 pp. &lt;a href=&quot;https://books.google.ca/books?id=p1Bs03rhZzwC&amp;amp;lpg=PA359&amp;amp;ots=-bg67Yned2&amp;amp;pg=PA359#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;nofollow&quot;&gt;In Google Books.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2016-05-09T11:37:14.713" LastActivityDate="2016-05-09T11:37:14.713" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7966" PostTypeId="2" ParentId="7960" CreationDate="2016-05-07T18:16:58.447" Score="5" Body="&lt;p&gt;Most of our geographic and astronomic terms were developed in pre-history in the northern hemisphere. Even early astronomers noticed that Polaris, the north star, was 'up' in the night sky, so north as 'up' simply became the convention.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-05-07T18:16:58.447" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7967" PostTypeId="2" ParentId="7958" CreationDate="2016-05-07T18:29:59.120" Score="4" Body="&lt;p&gt;If you live in a part of the world where the rainfall is dominated by frontal systems, and mainly by cold fronts, then there is a rough inverse correlation between pressure and rain. Otherwise, no. As Gerrit pointed out, rainfall is a whole lot more complicated than that. If you are looking for something to correlate with rain then I suggest you look into satellite-based cloud-top temperatures. The supercooled temperatures at the top of cumulus towers does correlate tolerably well with rainfall. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-05-07T18:29:59.120" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7968" PostTypeId="2" ParentId="7921" CreationDate="2016-05-07T21:37:28.247" Score="6" Body="&lt;p&gt;The borders are fluent between continentality and maritimity. However, there are several indices, aiming to clarify this question. For instance, the probably earliest one is from Gorczynski (1920):&#xA;&lt;span class=&quot;math-container&quot;&gt;$$K_{Gorczynski} = 1.6 \cdot \frac{A}{\sin \varphi} - 14$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; is the annual temperature amplitude of the location and &lt;span class=&quot;math-container&quot;&gt;$\varphi$&lt;/span&gt; the latitude of the location. Another one, which is more often used, is from Iwanow (1956):&#xA;&lt;span class=&quot;math-container&quot;&gt;$$K_{Iwanow} = 260 \cdot \frac{\Delta T}{\varphi}$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$\varphi$&lt;/span&gt; is the latitude again and&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\Delta T=T_\mathrm{max} - T_\mathrm{min}$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$T_\mathrm{max}$&lt;/span&gt; is the temperature maximum and &lt;span class=&quot;math-container&quot;&gt;$T_\mathrm{min}$&lt;/span&gt; the temperature minimum. The results are characterized as following:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;K &amp;lt; 100: maritime&lt;/li&gt;&#xA;&lt;li&gt;100 &amp;lt; K &amp;lt; 200: continental&lt;/li&gt;&#xA;&lt;li&gt;K &gt; 200: strongly continental&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;To answer the second part of the question: as the indices show, the latitude needs to be considered. Currently I do not have the original publication by Gorczynski or Iwanow here, however there are some papers comparing different indices (there are several more), for example &lt;a href=&quot;https://www.erdkunde.uni-bonn.de/archive/1989/continentality-indices.-methodological-revision-and-proposition/at_download/attachment&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one&lt;/a&gt;. Furthermore, the indices can be looked up in the most climatology basic literature and &lt;a href=&quot;https://books.google.de/books?id=-mwbAsxpRr0C&amp;amp;pg=PA304&amp;amp;lpg=PA304&amp;amp;dq=Gorczynski%201920#v=onepage&amp;amp;q=Gorczynski%201920&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;encyclopedia&lt;/a&gt;. At least, it is needed to mention that Gordon Stanger hits the point in his answer in the last sentence: The continentality is just &lt;em&gt;one&lt;/em&gt; variable - there are several more. Look for climate classifications, like those from Köppen &amp;amp; Geiger or Schultz.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Edit: Original reference&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gorczynski, L. (1920): Sur le calcul du degre de continentalisme et son application dans la climatologie. In: Geografiska Annaler 2, p. 324-331. &lt;/p&gt;&#xA;" OwnerUserId="4784" LastEditorUserId="4784" LastEditDate="2018-12-25T15:11:59.863" LastActivityDate="2018-12-25T15:11:59.863" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="7969" PostTypeId="2" ParentId="7926" CreationDate="2016-05-08T01:52:03.477" Score="1" Body="&lt;p&gt;Yes/no. In a cloud microphysics standpoint, you do need relative humidities greater than 100%, otherwise you cannot form clouds. However, for WRF output, you may want to check the script you are using to compute the dewpoint temperature. You may also want to check to see if you have editted the microphysics code.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2016-05-08T01:52:03.477" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7970" PostTypeId="1" AcceptedAnswerId="7971" CreationDate="2016-05-08T02:17:55.480" Score="10" ViewCount="37485" Body="&lt;p&gt;As part of a course on Natural Disasters, I have a group presentation in which we focus on a specific natural disaster. One of the questions we have to address is how human activity may have affected the geographic area and/or the disaster. The topic for our group is volcanoes, with a specific focus on the Mount St. Helens eruption in 1980. So my question is — is this possible?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The closest I can think of is human-induced seismic activity, due to fracking or wastewater injection, for example. However, I do not know if this could conceivably also affect in any way nearby volcanism. I also don't think there are or have been any oil-related activities around Mount St. Helens, but I really don't know for sure. So, is this possible?&lt;/p&gt;&#xA;" OwnerUserId="5949" LastEditorUserId="28050" LastEditDate="2016-05-09T13:21:35.813" LastActivityDate="2018-10-28T07:21:06.080" Title="Can human activity affect volcanoes?" Tags="|volcanology|human-influence|volcanic-hazard|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7971" PostTypeId="2" ParentId="7970" CreationDate="2016-05-08T09:56:25.397" Score="10" Body="&lt;p&gt;I think you have drawn the 'short straw'! As disasters go, volcanoes have about the least to do with human activity. Basically, volcanoes are the product of plate tectonics, which operates on a scale vastly greater than human impacts on the planet. At least one book has been written about earthquakes, volcanoes and human impacts, but the linkage is tenuous at best. The argument goes something like this: Humans modify the water table by pumping, diverting water, building dams, etc. Also by human-induced climate change contributing to rising sea levels. Increased hydrostatic pressure in the ground 'lubricates' fault planes causing lesser but more frequent earthquakes. In and around volcanoes, there is more groundwater which increases water vapour in/near magma chambers, and hence increases the activity of volatiles, contributing to volcanic eruptions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is all speculative, and most geologists doubt whether these effects are significant, or even if they exist at all. I think you will have a hard task trying to provide supporting evidence for any of this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand there is passive interaction in that many terrestrial volcanoes in wet climates produce vast quantities of volcanic ash that weathers rapidly to produce fertile soil. This fertility attracts farming communities who put themselves in harms way, being at risk from hot ash clouds, hot lava, volcanic bombs and mudflows. The latter are produced by hurricane level rainfall mobilizing the loose ash, such that mudflows (or 'lahars') kill far more people than the volcanoes themselves - we have seen many examples in the news in recent decades - in South and Central America, Indonesia, Philippines, etc. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Mount St. Helens eruption was caused by the Juan de Fuca tectonic plate subducting under North America. It's a 100% natural process, with no human causation whatever. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are no known cases of fracking having any impact upon volcanoes. Can you imagine any fracking company taking the legal risk of setting off a volcanic eruption? In any case, the basic geology of volcanoes and hydrocarbon bearing sediments is quite different. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-05-08T09:56:25.397" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7972" PostTypeId="2" ParentId="96" CreationDate="2016-05-08T12:22:53.800" Score="-2" Body="&lt;p&gt;Water actually was never present on Earth before its creation and that is for sure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Astronomers realized that there are two ready-made sources: comets and asteroids, the solar system’s gravel strewn among planetary boulders. The primary difference between the two is that comets typically have a greater concentration of ingredients that vaporize when heated, accounting for their iconic gaseous tails. Both comets and asteroids can contain ice. And if, by colliding with Earth, they added the amount of material some scientists suspect, such bodies could easily have delivered oceans’ worth of water. Accordingly, each has been fingered as a suspect in the mystery.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Adjudicating between the two is a challenge, and over the years scientific judgment has swung from one to the other. Nevertheless, recent observations of their chemical makeups are tipping the scale toward asteroids. Researchers reported last year, for example, that the ratios of different forms of hydrogen in asteroids appear to better match what we find here on Earth. But the analyses are based on limited samples, meaning there’s a good chance we’ve not yet heard the final word&lt;/p&gt;&#xA;" OwnerUserId="5953" LastActivityDate="2016-05-08T12:22:53.800" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7973" PostTypeId="1" AcceptedAnswerId="7974" CreationDate="2016-05-08T18:18:53.907" Score="7" ViewCount="184" Body="&lt;p&gt;I get my weather forecasts from good ol' &lt;a href=&quot;http://www.noaa.gov&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA&lt;/a&gt;'s &lt;a href=&quot;http://www.weather.gov&quot; rel=&quot;nofollow noreferrer&quot;&gt;weather.gov&lt;/a&gt; site. On the detailed site weather pages, there's a map that shows the forecast area as a green square (for Boston at least, the square is about 1.5 miles on a side). You can click on nearby areas to change the presented forecast to that new location.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's the question: why is the square shown as the forecast area not oriented north/south/east/west? For some reason, near the US East Coast it's twisted clockwise, and on the West Coast it's twisted counter-clockwise. I assume it's something about the easy representation of weather information in a GIS system, but that's only a guess.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are some examples, from East to West. First, &lt;a href=&quot;http://forecast.weather.gov/MapClick.php?lon=-71.0586870876267&amp;amp;lat=42.36143032801277&quot; rel=&quot;nofollow noreferrer&quot;&gt;Boston&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Hh1cV.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Hh1cV.png&quot; alt=&quot;Boston, MA forecast area&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second &lt;a href=&quot;http://forecast.weather.gov/MapClick.php?lat=39.768376841000475&amp;amp;lon=-86.15803708099969&quot; rel=&quot;nofollow noreferrer&quot;&gt;Indianapolis&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/L14nG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/L14nG.png&quot; alt=&quot;Indianapolis, IN forecast area&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Third, &lt;a href=&quot;http://forecast.weather.gov/MapClick.php?lon=-104.97121589355471&amp;amp;lat=39.78560985063913&quot; rel=&quot;nofollow noreferrer&quot;&gt;Denver&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Zv898.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Zv898.png&quot; alt=&quot;Denver, CO forecast area&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fourth, &lt;a href=&quot;http://forecast.weather.gov/MapClick.php?lon=-122.42891992340103&amp;amp;lat=37.75566584959775&quot; rel=&quot;nofollow noreferrer&quot;&gt;San Francisco&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WHkJ7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WHkJ7.png&quot; alt=&quot;San Francisco, CA forecast area&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that, if you go even further west to &lt;a href=&quot;http://forecast.weather.gov/MapClick.php?lon=-155.08789&amp;amp;lat=19.71275&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hawaii&lt;/a&gt;, the pattern breaks, and the square is perfectly north/south/east/west:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZhnjT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZhnjT.png&quot; alt=&quot;Hilo, HI forecast area&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, any ideas?&lt;/p&gt;&#xA;" OwnerUserId="534" LastEditorUserId="543" LastEditDate="2017-01-29T21:17:10.787" LastActivityDate="2017-01-29T21:17:10.787" Title="Why do forecast areas on weather.gov appear as twisted squares?" Tags="|meteorology|weather-forecasting|gis|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7974" PostTypeId="2" ParentId="7973" CreationDate="2016-05-09T00:43:35.793" Score="13" Body="&lt;p&gt;The equal-area projection used to create the continental U.S. grid for weather forecasting does not represent lines of latitude and longitude as straight lines.  Instead, they are curved (note the Canada-USA border curvature below, which is actually along the 49th latitude parallel).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An equal-area projection is often used in regional weather modeling because it is important for each cell to represent the same amount of physical space during computation.  The map images posted in the question are using the Mercator (or Mercator for web) projection, where lines of latitude are horizontal and lines of longitude are vertical, but area is distorted. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The grid-cells from the regional model are also designed in a way that maximizes cost-benefit of computational power.  You want to minimize the number of grid cells modeled while maximizing the number of grid-cells in your domain that are relevant to your study area.  This ensures that you aren't wasting computational power and is often achieved by changing the orientation of the domain a little.  So, the grid cells do not align nicely on the mercator map used on web-app maps like google, bing, etc.  However, the grid-cells line up perfectly if visualized using the native projection for the image frame (e.g. below).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason that Hawaii does not follow the pattern is that the data for Hawaii is obtained from a model simulation for a different grid.  The nesting of grids can be seen in the image below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suggest you read &lt;a href=&quot;http://cdn.intechopen.com/pdfs-wm/43438.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Grids in Numerical Weather and Climate Models&#xA;&lt;/a&gt; for a nice look at the factors involved when choosing a grid definition.&#xA;You could also &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/model-data/model-datasets/north-american-mesoscale-forecast-system-nam&quot; rel=&quot;nofollow noreferrer&quot;&gt;look here&lt;/a&gt; for more info about NOAA prediction.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/d1Uok.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/d1Uok.jpg&quot; alt=&quot;http://www.ncep.noaa.gov/newsletter/january2012/&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;North American Mesoscale (NSM) forecast model domains used by NOAA.&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2016-05-11T04:20:38.220" LastActivityDate="2016-05-11T04:20:38.220" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7975" PostTypeId="1" AcceptedAnswerId="7980" CreationDate="2016-05-09T02:29:39.343" Score="2" ViewCount="744" Body="&lt;p&gt;I have constantly been told through my K-12 Education that diamonds are a product of carbon, time, pressure, and temperature. If this is true, what is stopping someone from building a high-pressure, high-temperature system and dumping graphite in and making millions of diamonds?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems my exact strategy is listed here: &lt;a href=&quot;https://en.wikipedia.org/wiki/Synthetic_diamond#High_pressure.2C_high_temperature&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Synthetic_diamond#High_pressure.2C_high_temperature&lt;/a&gt; . But this is under the article &quot;synthetic diamond.&quot; How can one tell a difference between a synthetic diamond and a &quot;real&quot; diamond? What is stopping someone from making these HPHT machines and making tons of money?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Update: I watched the BBC special on synthetic diamonds (&lt;a href=&quot;https://www.youtube.com/watch?v=5d2WebdMpBQ&quot; rel=&quot;nofollow&quot;&gt;https://www.youtube.com/watch?v=5d2WebdMpBQ&lt;/a&gt;) and De Beers shows you can tell the difference between synthetic and real diamonds by their reaction to UV radiation. I am still interested in how I can make a DIY diamond if anyone has details on that. And to make this more on topic, how best I can simulate the Earth's formation of diamond? Why is the Earth's formation of diamond different from these HPHT and CVD diamonds?&lt;/p&gt;&#xA;" OwnerUserId="5132" LastEditorUserId="725" LastEditDate="2016-05-10T09:38:30.227" LastActivityDate="2016-05-10T09:59:30.940" Title="What does it take to make a diamond?" Tags="|temperature|economic-geology|diamond|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7977" PostTypeId="2" ParentId="7970" CreationDate="2016-05-09T13:07:32.270" Score="7" Body="&lt;p&gt;&lt;strong&gt;Yes. Human activity can probably cause volcanic eruptions, albeit indirectly. Regardless, human activity affects volcanic disasters in several other ways.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, let's look at how humans can cause volcanic eruptions.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Humans affect climate, and climate affects volcanos&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Kutterolf et al. (2012) showed recently that climate affects the frequency of volcanic eruptions, chiefly through changes in global sea-level and isostatic effects. Ice unloading can also trigger eruptions in places like Iceland, as researched by Sigmundsson et al. (2010). So it seems highly likely that human-caused climate change will affect the frequency of volcanic eruptions, although &lt;a href=&quot;http://www.livescience.com/25936-climate-change-causes-volcanism.html&quot; rel=&quot;noreferrer&quot;&gt;according to one of the scientists&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We predict there's a time lag of about 2,500 years,&quot; [co-author] Jegen said. &quot;So even if we change the climate, you wouldn't really expect anything to happen in the next few thousand years.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The lead author &lt;a href=&quot;http://phys.org/news/2012-12-ice-earth-spews-link-climate.html&quot; rel=&quot;noreferrer&quot;&gt;adds&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The impact from man-made warming is still unclear based on our current understanding.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Clearly this climate cause is rather indirect. And certainly the extent to which it's an issue today is open to debate. As you suggest, there may be some others causes. But, either way...&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Humans affect disasters even if they don't &lt;em&gt;cause&lt;/em&gt; them&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Humans can contribute to disasters in other ways than being the root cause of the natural phenomenon. They are relevant to how natural phenomena affect humans; if they don't affect humans, we don't call them 'disasters'. Think about things like the following:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;How we educate people about natural hazards that might affect them.&lt;/li&gt;&#xA;&lt;li&gt;How we design early warning and emergency response systems.&lt;/li&gt;&#xA;&lt;li&gt;Where we choose to build our dwellings.&lt;/li&gt;&#xA;&lt;li&gt;Where we build transportation and other support systems.&lt;/li&gt;&#xA;&lt;li&gt;How we manage forests and farming.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Read about hazard evaluation, monitoring, and avoidance, for example around famous &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_volcanic_eruptions_by_death_toll&quot; rel=&quot;noreferrer&quot;&gt;recent eruptions&lt;/a&gt;. Some of these, such as Montserrat, are especially well studied. &lt;a href=&quot;http://www.bgs.ac.uk/discoveringGeology/hazards/volcanoes/montserrat/home.html&quot; rel=&quot;noreferrer&quot;&gt;This BGS page&lt;/a&gt; has some more info on that volcano.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;A couple more things&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Humans almost certainly had something to do with a &lt;strong&gt;mud&lt;/strong&gt; volcano eruption, which displaced thousands of people in Indonesia in 2006: the Lumpur Lapindo eruption, which is coming up on its 10th anniversary. Read &lt;a href=&quot;http://www.agilegeoscience.com/blog/2014/5/28/lusis-8th-birthday.html&quot; rel=&quot;noreferrer&quot;&gt;my article&lt;/a&gt; from it's 8th birthday, and see &lt;a href=&quot;https://earthscience.stackexchange.com/q/4232/70&quot;&gt;this question&lt;/a&gt;. Obviously, this is a completely different kind of volcano.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to &lt;em&gt;start&lt;/em&gt; an eruption, &lt;a href=&quot;https://twitter.com/eruptionsblog&quot; rel=&quot;noreferrer&quot;&gt;Erik Klemetti&lt;/a&gt; (a legit vulcanologist) &lt;a href=&quot;http://www.wired.com/2012/04/could-people-trigger-a-volcanic-eruption-on-purpose/&quot; rel=&quot;noreferrer&quot;&gt;has some tips&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kutterolf, S., M. Jegen, J. X. Mitrovica, T. Kwasnitschka, A. Freundt, P. J. Huybers (2012): A detection of Milankovitch frequencies in global volcanic activity. &lt;em&gt;Geology&lt;/em&gt;, G33419.1, &lt;a href=&quot;http://dx.doi.org/10.1130/G33419.1&quot; rel=&quot;noreferrer&quot;&gt;DOI 10.1130/G33419.1&lt;/a&gt;. &lt;a href=&quot;http://phys.org/news/2012-12-ice-earth-spews-link-climate.html&quot; rel=&quot;noreferrer&quot;&gt;Read more.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sigmundsson, Freysteinn, Virginie Pinel, Björn Lund, Fabien Albino, Carolina Pagli, Halldór Geirsson, Erik Sturkell (2010). Climate effects on volcanism: influence on magmatic systems of loading and unloading from ice mass variations, with examples from Iceland. &lt;em&gt;Phil. Trans. R. Soc. A&lt;/em&gt; 2010 &lt;strong&gt;368&lt;/strong&gt; 2519-2534; DOI: &lt;a href=&quot;http://dx.doi.org/10.1098/rsta.2010.0042&quot; rel=&quot;noreferrer&quot;&gt;10.1098/rsta.2010.0042&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-05-09T19:13:25.280" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7979" PostTypeId="2" ParentId="7954" CreationDate="2016-05-10T08:49:13.063" Score="0" Body="&lt;p&gt;There is probably no such thing as a totally comprehensive list of minerals because nobody agrees upon what constitutes a mineral, as opposed to a multiple variants of the same mineral. There is also a grey area between 'natural' and 'synthetic'.&lt;br&gt;&#xA;That said, however, the international centre for diffraction data (i.e. for X-ray powder diffraction work) has a recent catalogue of minerals called PDF-4 +2015, which includes more than 365,000 entries! You may have to sift through the catalogue to determine which are genuinely natural minerals that you want in your own catalogue. The '-4' indicates actual minerals as opposed to pharmaceuticals etc, which are under a different catalogue. &#xA;You can access their flyer from:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.icdd.com/products/flyers/PDF-4plus.pdf&quot; rel=&quot;nofollow&quot;&gt;http://www.icdd.com/products/flyers/PDF-4plus.pdf&lt;/a&gt;  &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-05-10T08:49:13.063" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7980" PostTypeId="2" ParentId="7975" CreationDate="2016-05-10T09:38:14.740" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;what is stopping someone from building a high-pressure, high-temperature system and dumping graphite in and making millions of diamonds?&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;What is stopping someone from making these HPHT machines and making tons of money?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No one, and it is done. First of all, synthetic diamonds have been out on the market for quite some time now and it's a well established business. You've heard of diamond saws, diamond drills, diamond polishing paste and all kinds of other diamond products. So people make them, sell them, and make money.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's not even that hard: In our own lab we got a machine that can make diamonds (among other HPHT) stuff. Someone once even put some peanut butter and made diamonds out of it (micrometre sized, though). Here's a picture of the machine (called a piston cylinder):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/3X5e9.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3X5e9.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a picture of how this might look:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yzyno.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yzyno.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that this one is not from our lab, but it's a really nice picture of how this stuff looks when you make it in such machines. This one's from &lt;a href=&quot;http://www.canmin.org/cgi/doi/10.3749/canmin.46.4.991&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt;. The diamond crystals are about 30 μm across. Not something you'd put on a ring.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The big question is how do you make gemstone quality diamonds. Chemical vapour deposition seems like the most successful method. There are other methods, but it's pretty easy to distinguish them from natural diamonds (&lt;a href=&quot;https://www.researchgate.net/profile/Andrey_Katrusha2/publication/274736406_Colorless_HPHT-Grown_Gem_Diamonds_from_New_Diamond_Technology/links/55296c570cf2e089a3a7d393.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;example&lt;/a&gt;). It is still quite hard to do it: it's not something anyone can just do in their backyard. With technology it becomes easier though. Here comes the question of regulation. Gemesis, one of the companies that makes them, &lt;a href=&quot;http://gemesis.com/media/wysiwyg/ExDiamondCert.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;engraves a serial number&lt;/a&gt; using laser on each synthetic gem-quality diamond they make. But what about some evil diamond makers who want to simulate natural stones? As with any other synthetic material, there are imperfections that are different from imperfections found in natural stones.  Moreover, each mine or region where diamonds come from has a different fingerprint (&lt;a href=&quot;http://sajg.geoscienceworld.org/content/115/1/33.short&quot; rel=&quot;nofollow noreferrer&quot;&gt;they use that to trace blood diamonds&lt;/a&gt;). There are methods to analyse the diamonds to detect this. UV and IR spectroscopy, laser ablation, isotope analysis, cathodoluminescence and others. Some are easier and cheaper than others.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So you can't just make up impurities to say &quot;look it's natural&quot;, they have to be consistent with a specific diamond source you're trying to imitate. And that's - not very easy. Likely impossible with today's technology.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2016-05-10T09:59:30.940" LastActivityDate="2016-05-10T09:59:30.940" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7981" PostTypeId="1" CreationDate="2016-05-10T13:02:49.450" Score="7" ViewCount="200" Body="&lt;p&gt;I recently visited a cliff on the south coast of Ulva in the Inner Hebrides where there are ~10m thick flows of columnar basalt. The columnar basalt forming most of the cliff is sandwiched between flows of non-columnar basalt in the same location. What factors could therefore trigger the formation of columns in &lt;em&gt;some&lt;/em&gt; basalt flows, but &lt;em&gt;not&lt;/em&gt; in others? At the base of the columns there was evidence of &quot;red bole&quot;, suggesting that there was some time between the flow of the lower non-columnar basalt and the columnar basalt above.&lt;/p&gt;&#xA;" OwnerUserId="5958" LastEditorUserId="94" LastEditDate="2017-01-08T18:41:41.420" LastActivityDate="2017-01-08T18:41:41.420" Title="Basalt vs. columnar basalt" Tags="|volcanology|rocks|igneous|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7982" PostTypeId="1" CreationDate="2016-05-11T11:52:08.923" Score="4" ViewCount="617" Body="&lt;p&gt;I understand that volcanic ash contains minerals and can make soil more fertile.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I've also heard the term &quot;fertile ash&quot; in some documentary (I have forgotten in what context). Is that a scientific term, or a  misnomer?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Oxford online dictionary contains the following definition of &quot;fertile&quot;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.oxforddictionaries.com/definition/english/fertile&quot; rel=&quot;nofollow&quot;&gt;http://www.oxforddictionaries.com/definition/english/fertile&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;1 (Of soil or land) producing or capable of producing abundant&#xA;  vegetation or crops: the fertile coastal plain&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;1.1 Producing many new and inventive ideas: her fertile imagination&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;1.2 (Of a situation) encouraging a particular activity or feeling: conditions at the time provided fertile ground for revolutionary&#xA;  movements&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;2 (Of a person, animal, or plant) able to conceive young or produce&#xA;  seed.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;2.1 (Of a seed or egg) capable of becoming a new individual.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;2.2 Physics (Of nuclear material) able to become fissile by the capture of neutrons.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;By that definition, ash alone cannot be described as fertile.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Perhaps a philosophical point, but if it's not valid according to this dictionary, and it's not a scientific term either, then I suppose it's more a question of correct English, so maybe I should reword my title to ask if it's a scientific term.&lt;/p&gt;&#xA;" OwnerUserId="5960" LastEditorUserId="94" LastEditDate="2016-10-12T14:32:30.550" LastActivityDate="2018-09-11T09:11:06.410" Title="Is the term &quot;fertile ash&quot; a misnomer?" Tags="|volcanology|terminology|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="7983" PostTypeId="2" ParentId="7982" CreationDate="2016-05-11T12:29:34.247" Score="8" Body="&lt;p&gt;'Fertile ash' is not a scientific term, but neither is it a misnomer. Unless the ash is deposited really hot - hot enough for the particles to weld together as 'ignimbrite', then the ash deposit has high porosity and permeability. As soon as water infiltrates, the anhydrous minerals start weathering to clay - generally smectite, or mixed layer clays. This released aqueous magnesium, silica, and low concentrations of other elements crucuial to plants. Thus, both the texture and chemistry of volcanic ash is conducive to plant growth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the volcanic island of Surtsey emerged from the Atlantic, just south of Iceland, in the 1970s, plants started to establish themselves in the volcanic ash within a matter of months. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-05-11T12:29:34.247" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7985" PostTypeId="2" ParentId="7982" CreationDate="2016-05-11T20:35:10.347" Score="5" Body="&lt;p&gt;There are actually two slightly different ways to interpret the phrase &quot;fertile ash&quot;. Both are valid, and you'd need to look at the context of the phrase to determine exactly which is meant (this is why I asked where you came across the term).&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Sense 1: &quot;fertile&quot; in the sense of &quot;helping fertility&quot;&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;The &lt;em&gt;Oxford English Dictionary&lt;/em&gt;, under the entry for ‘fertile &lt;em&gt;adj.&lt;/em&gt;’, gives:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Causing or tending to promote fertility.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The first citation for this sense of the word is from 1597. Other dictionaries contain similar definitions: the &lt;a href=&quot;https://ahdictionary.com/word/search.html?q=fertile&quot; rel=&quot;nofollow noreferrer&quot;&gt;American Heritage Dictionary&lt;/a&gt; has &quot;Rich in material needed to sustain plant growth&quot;; &lt;a href=&quot;http://www.dictionary.com/browse/fertile?s=t&quot; rel=&quot;nofollow noreferrer&quot;&gt;dictionary.com&lt;/a&gt; has &quot;conducive to productiveness&quot;; and &lt;a href=&quot;http://www.yourdictionary.com/fertile#websters&quot; rel=&quot;nofollow noreferrer&quot;&gt;Webster's New World College Dictionary&lt;/a&gt; has &quot;causing or helping fertility&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since, as you acknowledge, ash can make soil more fertile, the collocation &quot;fertile ash&quot; seems perfectly valid. If by &quot;not valid according to the Oxford dictionary&quot; you mean that that specific combination of words isn't listed, you're using a very odd definition of &quot;valid&quot;: there are a huge number of adjectives which can reasonably be applied to any noun, and you can't expect every possible combination to be listed in a dictionary.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Sense 2: &quot;fertile&quot; in the sense of &quot;producing vegetation&quot;&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/7983/94&quot;&gt;Gordon Stanger's answer&lt;/a&gt; provides a good explanation of how the term &quot;fertile ash&quot; works under the interpretation of &quot;producing vegetation&quot; in itself, rather than as an admixture: while newly deposited ash is unlikely to support plant growth on its own, a relatively small amount of weathering makes it an excellent substrate for plant colonization. For instance, Parnell and Foster (2012) write:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The physical attributes of volcanic ash allow good drainage, but also high retention of plant-available water, which would have been essential to the earliest plants occupying moist lowland areas. It also provides excellent ‘tilth’, the physical condition related to fitness as a seed-bed. The combination of water and nutrient availability would have made ashes a favourable setting for the seeding of primitive plants.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Of course, at some point in the weathering process it becomes more of an &quot;ash soil&quot; than an &quot;ash&quot; -- as with many categories in Earth Science, the boundary is a little fuzzy. But given the speed with which ash deposits are colonized, I think it's fair to say that they're fertile (in the sense of &quot;producing vegetation&quot;) even while still in the &quot;ash&quot; category.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Usage as a scientific term&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;You can find the term &quot;fertile ash&quot; used in many peer reviewed scientific publications -- for example, May et al. (1985), Eckmeier et al. (2007), Sullivan (1982), and Utkin (2013). Thus, it's a scientific term in the sense of a term which can be (and is) used in scientific writing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's not entirely clear to me what you mean by a &quot;scientific term&quot;. I agree with Gordon Stanger that it's not a &quot;scientific term&quot;, in the sense that you won't find a specific entry for it in a scientific reference work -- it's just an adjective applied to &quot;ash&quot;, not a specific, extensively studied topic. Nor is it one of those terms which has a different meaning in a specific scientific context (like &lt;a href=&quot;https://en.wikipedia.org/wiki/Catastrophism&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;catastrophic&quot;&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnetic_domain&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;domain&quot;&lt;/a&gt;). When used in science writing, it could certainly be called a scientific term, but its meaning is the same as when used in everyday language.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Conclusion&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;&quot;Fertile ash&quot; is not a misnomer; it has at least two reasonable interpretations, in terms of dictionary definitions of its constituent words; and it is a &quot;scientific term&quot; in the sense of a term that can be used in scientific publications.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Responses to comments&lt;/h3&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;can you include a screenshot of the definition?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm unsure how this improves the answer, but am happy to oblige:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/McHru.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/McHru.png&quot; alt=&quot;OED definition&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(If you meant that I should screenshot the entire entry, I'm afraid that's not practical -- it's hundreds of words long and thousands of pixels tall, and would add enormous bulk to this answer without providing any relevant additional information!)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;it's not listed on dictionary.cambridge.org for example nor is it listed on the oxforddictionaries link in my question&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Many dictionary publishers don't make their most complete dictionaries freely available online. As far as I know, all the dictionaries available on CUP's site are for learners of English, and thus aren't particularly extensive. OUP's free offering is is (I think) based on their 1-volume &lt;em&gt;Oxford Dictionary of English&lt;/em&gt;, rather than the full &lt;em&gt;Oxford English Dictionary&lt;/em&gt;. They're certainly good starting points, but don't expect them to be exhaustive.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Eckmeier, E., Rösch, M., Ehrmann, O., Schmidt, M. W., Schier, W., &amp;amp; Gerlach, R. (2007). Conversion of biomass to charcoal and the carbon mass balance from a slash-and-burn experiment in a temperate deciduous forest. The Holocene, 17(4), 539-542.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;May, P. H., Anderson, A. B., Balick, M. J., &amp;amp; Frazão, J. M. F. (1985). Subsistence benefits from the babassu palm (Orbignya martiana). Economic Botany, 39(2), 113-129.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Parnell, J., &amp;amp; Foster, S. (2012). Ordovician ash geochemistry and the establishment of land plants. Geochemical transactions, 13(1), 7.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sullivan, A. P. (1982). Mogollon Agrarian Ecology: An Appraisal and a New Model. The Kiva, 1-15.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Utkin, V. P. (2013). Shear structural paragenesis and its role in continental rifting of the East Asian margin. Russian Journal of Pacific Geology, 7(3), 167-188.&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-10-13T07:10:14.820" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="7986" PostTypeId="1" AcceptedAnswerId="8085" CreationDate="2016-05-12T01:06:14.793" Score="9" ViewCount="1095" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Ekman_transport&quot; rel=&quot;nofollow&quot;&gt;Ekman transport&lt;/a&gt; is the integrated horizontal flow in the boundary layer resulting from the balance between frictional forces (at the surface or bottom) and Coriolis. Meanwhile, &lt;a href=&quot;http://oceanworld.tamu.edu/resources/ocng_textbook/chapter12/chapter12_03.htm&quot; rel=&quot;nofollow&quot;&gt;Ekman pumping&lt;/a&gt; is a vertical motion at the base of the boundary layer resulting from the curl of the wind. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is the relationship between Ekman transport and Ekman pumping?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2016-05-13T13:07:49.027" LastActivityDate="2016-05-29T23:14:32.670" Title="What is the relationship between Ekman transport and Ekman pumping?" Tags="|ocean|oceanography|ocean-currents|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7988" PostTypeId="1" CreationDate="2016-05-12T08:22:09.310" Score="2" ViewCount="242" Body="&lt;p&gt;Last day we had first rain after 3-4 months of hot&amp;amp;dry weather, and within 3-4 minutes a rotting smell came from nowhere. Due this smell I had running nose for a day. What might be the reason for this bad smell? Did anyone heard of this kind of problem? (or is this just some local issue related to sewage, or some animal dead body which was dry came in contact with water)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not referring to &lt;a href=&quot;https://en.wikipedia.org/wiki/Petrichor&quot; rel=&quot;nofollow&quot;&gt;Petrichor&lt;/a&gt;, which is fresh earthly smell.&#xA;And I am in India.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;I hope this is on-topic here&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="5966" LastActivityDate="2016-05-13T15:51:23.763" Title="Reason for rotting smell after first rain of the season?" Tags="|temperature|rainfall|earth-system|rain|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7990" PostTypeId="1" CreationDate="2016-05-12T12:46:08.617" Score="6" ViewCount="342" Body="&lt;p&gt;Given that Pangaea had C-shape can we assume that the point of impact was in the center of this C-shape? In modern world it would be under Tibet? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5Clzj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5Clzj.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or should we assume the oldest shape of the supercontinent was circular so that the impact point was somewhere in North America?&lt;/p&gt;&#xA;" OwnerUserId="2819" LastEditorUserId="725" LastEditDate="2016-05-12T23:09:26.067" LastActivityDate="2016-05-12T23:09:26.067" Title="If we assume the mega impact hypothesis for the formation of Moon, where on Earth is the impact point?" Tags="|plate-tectonics|earth-history|impacts|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7991" PostTypeId="2" ParentId="7990" CreationDate="2016-05-12T13:42:27.950" Score="16" Body="&lt;p&gt;I think you are confused about the timescales and the magnitude of the impact that is being talked about here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The collision between the early Earth and a roughly Mars sized body, Theia is thought to have happened between 4.4 and 4.45 billion years ago. The Pangaea supercontinent had fully assembled by around 250 million years ago. Previous to this there are a number of other supercontinents which have been recognised, the oldest speculative ones dating back to around 3 billion years ago. The Earth's crust is constantly being reshaped by plate tectonics and so the location of an impact at 4.4 billion years ago has no bearing whatsoever on the orientation of the Pangaea (or any other) supercontinent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition, based on computer simulations of the impact, we know that the impactor mass must have been on the order of 0.1 Earth masses and the initial impactor velocity must have been something like 5 km/s. This means that &lt;strong&gt;a colossal quantity of energy would have been released by the impact which would completely reshape any surface structure (and much of the internal structure) that the Earth may have had at that early stage.&lt;/strong&gt; Indeed, a significant quantity of the mass of the two impactors was put into orbit around the Earth by the impact, either as solid debris, some of which coalesced to form the Moon, or as vaporised rock. Due to the complete lack of direct evidence, it is difficult to determine the exact impact parameters, including the impact angle. Some simulations suggest a fairly moderate angle of impact of around 45° &lt;sup&gt;[1]&lt;/sup&gt;, but there is some geochemical evidence from the Moon to suggest a higher angle of impact, with higher energies involved &lt;sup&gt;[2]&lt;/sup&gt;&lt;sup&gt;[3]&lt;/sup&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References:&lt;/strong&gt; &lt;br&gt;&#xA;  [1] &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0019103503002999&quot;&gt;http://www.sciencedirect.com/science/article/pii/S0019103503002999&lt;/a&gt; &lt;br&gt;&#xA;  [2] &lt;a href=&quot;http://science.sciencemag.org/content/351/6272/493.full&quot;&gt;http://science.sciencemag.org/content/351/6272/493.full&lt;/a&gt; &lt;br&gt;&#xA;  [3] &lt;a href=&quot;http://science.sciencemag.org/content/338/6110/1052.full&quot;&gt;http://science.sciencemag.org/content/338/6110/1052.full&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2016-05-12T13:42:27.950" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="7992" PostTypeId="1" CreationDate="2016-05-12T14:05:57.200" Score="1" ViewCount="1024" Body="&lt;p&gt;I'm looking to understand the chemical composition of the Spanish Nero Marquina Stone. Specifically, are the white veins of different composition than the black?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We are design studio pursuing work in this stone and are looking to deepen our knowledge of how we can manipulate it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rVkvF.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rVkvF.jpg&quot; alt=&quot;Nero Marquina Stone&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5968" LastEditorUserId="725" LastEditDate="2016-05-12T23:07:44.073" LastActivityDate="2016-11-17T22:04:08.787" Title="Specific Chemical Composition of Nero Marquina Marble" Tags="|geochemistry|sedimentology|economic-geology|limestone|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7993" PostTypeId="1" AcceptedAnswerId="7996" CreationDate="2016-05-12T20:20:31.920" Score="5" ViewCount="5561" Body="&lt;p&gt;I just listened to &lt;a href=&quot;https://www.youtube.com/watch?v=TCy_UOjEir0&quot; rel=&quot;noreferrer&quot;&gt;Ivar Giaever's speech on the climate change&lt;/a&gt;, and he raised following points which seem significant to me:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Temperature differences y/y are very small compared to natural&#xA;variation during the year, and the trend we see could be statistical&#xA;illusion, especially that the scientists who developed the method&#xA;were looking to demonstrate exactly that sort of trend.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The correlation between CO&lt;sub&gt;2&lt;/sub&gt; emissions and measured&#xA;temperature changes is not perfect.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ZS9Nc.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZS9Nc.jpg&quot; alt=&quot;http://jonova.s3.amazonaws.com/guest/de/temp-emissions-1850-ppt.jpg&quot;&gt;&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Can anyone provide evidence to mute those points?&lt;/p&gt;&#xA;" OwnerUserId="5971" LastEditorUserId="725" LastEditDate="2016-05-12T22:45:38.783" LastActivityDate="2020-02-22T23:45:55.220" Title="Looking for evidence against some points raised in Ivar Giaever's speech on climate change" Tags="|climate|climate-change|climate-models|" AnswerCount="4" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="7994" PostTypeId="2" ParentId="7993" CreationDate="2016-05-12T22:48:22.147" Score="4" Body="&lt;p&gt;a) Yes, global warming could be just a statistical fluctuation. But the consensus to date of climate scientists is that there's a 90% probability that more than half of the recent warming is due to human activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;b) The graph compares the amount of CO2 in the atmosphere with global surface temperatures. Given the complexity of the climate system -- and in particular the exchange of energy throughout the troposphere and hydrosphere -- there's no reason to assume surface temperatures would closely track CO2 concentration.&lt;/p&gt;&#xA;" OwnerUserId="30" LastActivityDate="2016-05-12T22:48:22.147" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="7995" PostTypeId="2" ParentId="7992" CreationDate="2016-05-12T23:07:11.307" Score="1" Body="&lt;p&gt;To a first order approximation, the black stuff and white stuff are the same. Both are calcite (CaCO&lt;sub&gt;3&lt;/sub&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only information I could find online was that it contains some impurities of Mg (as dolomite maybe?) and of Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;. This shouldn't matter too much to you. The black stuff is black because it is very fine grained, and of organic origin. This is a limestone - made from millions of dead animals. The mass of the rock is their shells, made of calcium carbonate. However, you need just a little bit of organic material and heat, and it all turns to graphite. Graphite is an excellent material in making stuff black. Even a small percentage of fine grained graphite dispersed in the rock will make it black. The white stuff is pure calcite. Dissolved and reprecipitated in fractures as coarse grained crystals without any graphite or other impurities. That's why it's white.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not sure what do you mean by &quot;manipulating&quot;. This rock (as all limestones) is very sensitive to acids: vinegar, lemon juice, carbonated drinks, etc. Put it out in the rain for several decades and you will see the damage. It's also very soft. Unlike granite, which can hardly be scratched, limestone will be scratched very easily.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-05-12T23:07:11.307" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="7996" PostTypeId="2" ParentId="7993" CreationDate="2016-05-13T04:55:34.437" Score="17" Body="&lt;p&gt;Ivar's graph is mischievous in trying to imply that there should be an exact correlation. The global air temperature is not a good parameter to chart against CO2 emissions because the increasing heat doesn't just warm up the air. Most of the heat goes into warming the upper layers of the oceans, but it is not a linear relationship. The ratio of air and ocean warming varies massively with the state of ocean current, in which El Nino is just the largest of several ocean oscillations. If, instead of graphing the global air temperature, he graphed the global heat absorbtion, he would have arrived at a much more uniform relationship to greenhouse gas emissions.&#xA;Ivar is an engineer and a physicist, not a climate scientist, and his inability (or unwillingness) to look at the holistic picture makes me doubt his climate change credentials.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="-1" LastEditDate="2016-11-24T13:09:32.200" LastActivityDate="2016-11-24T13:09:32.200" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7997" PostTypeId="2" ParentId="7992" CreationDate="2016-05-13T05:11:06.950" Score="0" Body="&lt;p&gt;The white veins are late stage crystallization products and are most likely pure calcite. As for the black matrix, almost all limestone contains a range of impurities such as clays and other silicates and/or a huge range of potential organics. I suggest that you powder some of the black matrix, dissolve it in acetic or hydrochloric acid, then filter or centrifuge the insoluble residue. Wash it a few times in distilled water, then dry. The inorganic components can be identified by X-ray diffraction. As a first indicator, you can check for organics by scanning the infra-red spectrum. Perhaps supplement this by a differential thermal analysis scan. Then you should have a good idea of what you are dealing with. In addition, you may wish to do a whole-rock analysis by X-ray fluorescence just to see if there happen to be any unexpected elements in the marble. For example, there is likely to be some Mg, Fe, Sr, Ba, Si, Al, and Mn.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-05-13T05:11:06.950" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="7998" PostTypeId="1" AcceptedAnswerId="7999" CreationDate="2016-05-13T07:11:48.827" Score="0" ViewCount="2226" Body="&lt;p&gt;I have read some articles explaining why rounded corners are more aesthetically pleasing, like &lt;a href=&quot;http://uxmovement.com/thinking/why-rounded-corners-are-easier-on-the-eyes/&quot; rel=&quot;nofollow&quot;&gt;this one&lt;/a&gt; and it all makes perfect sense but my question is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why does nature not have sharp corners? What is the law or set of laws that governs this behavior? &lt;/p&gt;&#xA;" OwnerUserId="5975" LastEditorUserId="2570" LastEditDate="2016-05-13T09:57:37.250" LastActivityDate="2019-05-14T11:15:28.717" Title="Why there are no sharp corners in nature?" Tags="|crystals|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="7999" PostTypeId="2" ParentId="7998" CreationDate="2016-05-13T09:34:17.287" Score="11" Body="&lt;p&gt;The premise of your question is entirely wrong. There are many examples of sharp corners in nature, the most obvious being well formed crystals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pyrite is a classic example that was mentioned by @wienein in the comments. In a ideal situation it forms cubic crystals with sharp edges.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EohJIm.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EohJIm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A classic non-crystalline example would be volcanic glasses such as obsidian, which fracture to produce extremely sharp edges and were historically used by some cultures for making blades and other sharp tools.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9CgE4m.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9CgE4m.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2016-05-13T09:34:17.287" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8000" PostTypeId="2" ParentId="7988" CreationDate="2016-05-13T15:51:23.763" Score="3" Body="&lt;p&gt;When rain displaces pore gasses in the soil, bubbles of soil gas are released into the atmosphere. It's impossible to be precise about the composition because it is so variable from place to place. It varies according to soil type, organic content, degree of rotting, temperature, and the microbiological cross section (itself hugely variable). Most soil gas is odourless, such as nitrogen, carbon dioxide, methane, etc. Others, like geosmin, are very smelly. In addition  to 'petrichor' there are terpenes, aldehydes, alcohols and esters, to name but a few of the natural volatile organic compounds.&#xA;Of course, one cannot rule out the foul smell or rotting animals in some places.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-05-13T15:51:23.763" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8001" PostTypeId="1" AcceptedAnswerId="8002" CreationDate="2016-05-13T16:05:55.710" Score="3" ViewCount="525" Body="&lt;p&gt;A lot of people seem to believe that the entire cause of global warming is that humans are emitting lots of carbon dioxide. However, according to a source I found online (I accept it may not be entirely trustworthy) roughly 46% of trees on the planet have been destroyed since the dawn of the human race, we cut down 15 billion trees every year! Another source I found says that 16 trees absorb the amount of CO&lt;sub&gt;2&lt;/sub&gt; the average active person emits every day (an active person emits roughly 1kg of CO&lt;sub&gt;2&lt;/sub&gt; every day). This means we have destroyed enough trees that we no longer can support 937.5 million people! It also means that those trees are no longer taking in 937.5 million kg of CO&lt;sub&gt;2&lt;/sub&gt; . Here's a line chart showing deforestation from 1800 to 2010. The deforestation rate has gone up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Ko6kS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ko6kS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Credits to the appropriate  authors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clearly, the global temperature of the Earth has gone up because of carbon dioxide, however the carbon dioxide has gone up because we are destroying plantlife. So, my question is: &quot;When talking about global warming, why does nobody talk about plantlife? Wouldn't plantlife have a more immediate effect on getting rid of carbon dioxide than limiting how much carbon dioxide we emit?&quot;.&lt;/p&gt;&#xA;" OwnerUserId="5977" LastEditorUserId="2470" LastEditDate="2016-05-15T13:50:10.030" LastActivityDate="2019-05-04T07:11:54.980" Title="Is it possible that a reduction in vegetation is a cause of global warming?" Tags="|climate-change|carbon-cycle|land-surface|deforestation|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8002" PostTypeId="2" ParentId="8001" CreationDate="2016-05-13T20:47:52.097" Score="12" Body="&lt;p&gt;The short answer is that people do talk about it.  It is commonly referred to as &quot;land use change&quot;.  In general, the carbon dioxide equivalent of the effects of land-use change is on the order of 10% of the total anthropogenic contribution to CO2 emissions.  This may seem small, but it is important to realize that land-based plants are only a portion of the carbon dioxide sinks. You can see below an image from globalcarbonproject.org that shows the relationship.  See &lt;a href=&quot;http://www.globalcarbonproject.org/carbonbudget/15/files/GCP_budget_2015_v1.02.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; for full presentation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/r9tUK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/r9tUK.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2016-05-13T22:09:06.113" LastActivityDate="2016-05-13T22:09:06.113" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8004" PostTypeId="1" AcceptedAnswerId="8005" CreationDate="2016-05-14T08:44:14.087" Score="4" ViewCount="5990" Body="&lt;p&gt;I've got an argument with a mate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;He thinks that the moon shadow angle can change from night to night.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, one night, the near side of the moon is half black/white, black side on top, white on the bottom, and he believes that it can change, and another night, be, for example, black section on the left, white on the right, all observable from the same point on the planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it right?&lt;/p&gt;&#xA;" OwnerUserId="5980" LastEditorUserId="725" LastEditDate="2016-05-14T09:42:39.317" LastActivityDate="2018-08-07T20:52:39.030" Title="Can the moon shadow angle change?" Tags="|moon|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8005" PostTypeId="2" ParentId="8004" CreationDate="2016-05-14T12:02:37.473" Score="7" Body="&lt;p&gt;&lt;strong&gt;Yes. The moon is lit by the sun, so as its position relative to the sun changes, so does the angle from which it is lit.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I recommend reading the Wikipedia page on &lt;a href=&quot;https://en.wikipedia.org/wiki/Lunar_phase&quot; rel=&quot;noreferrer&quot;&gt;lunar phase&lt;/a&gt; for a good overview, some data, and some good references. This diagram from that page more or less sums it up — the bottom row shows how the moon looks from the earth over the course of a lunar month:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/I8C0H.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/I8C0H.jpg&quot; alt=&quot;Diagram explaining phases of the moon. CC-BY-SA by Orion 8&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&lt;em&gt;Image is CC-BY-SA by Wikipedia user &lt;a href=&quot;https://en.wikipedia.org/wiki/Lunar_phase#/media/File:Moon_phases_en.jpg&quot; rel=&quot;noreferrer&quot;&gt;Orion 8&lt;/a&gt;.&lt;/em&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The angle of the shadow depends on the time of the observation, and many lunar calendars seem to rotate the lunar images (as above). But this one gives a hint to the shifting relative sun position:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/empuF.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/empuF.jpg&quot; alt=&quot;The lunar month&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&lt;em&gt;Image is of unknown origin, &lt;a href=&quot;http://oldeuropeanculture.blogspot.ca/2014/06/calendar.html&quot; rel=&quot;noreferrer&quot;&gt;found here&lt;/a&gt;. Unclear rights; fair use.&lt;/em&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2016-05-14T13:19:55.007" LastActivityDate="2016-05-14T13:19:55.007" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8006" PostTypeId="2" ParentId="8004" CreationDate="2016-05-14T13:04:27.173" Score="4" Body="&lt;p&gt;The apparent angle of the moon is a function of the 28-day lunar orbit, the time of day/night one is looking at the moon, and the latitude from which it is viewed. So, for example, the current (14 May 16) view of the moon is that it is on its side, 'boat shaped' on the equator, but will appear progressively more sideways the further towards the poles that it is viewed.&lt;br&gt;&#xA;There is a change in the shadow angle, but not obvious on a day to day basis. This is caused by the fact that the earth's spin axis is not perpendicular to the Earth-Moon orbital plane, so that is an annual wobble. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-05-14T13:04:27.173" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8008" PostTypeId="1" AcceptedAnswerId="8010" CreationDate="2016-05-15T02:08:39.200" Score="2" ViewCount="372" Body="&lt;p&gt;One day I was sitting in an Atlanta traffic jam wondering about all the engine exhaust heat warming the localised environment. Later that night, things will have cooled down. Where did the heat go?  On a global scale, I understand our sun heats the earth via radiation, not conduction as  the intervening vacuum of space cannot transfer heat. So if the sun has been beaming gazillions of watts of energy into the earth over the last few billion years, and energy is conserved and the earth does not radiate out daily a material proportion of the radiation it has absorbed, where has all that energy gone?&lt;/p&gt;&#xA;" OwnerUserId="5983" LastEditorUserId="5983" LastEditDate="2016-05-15T11:00:14.043" LastActivityDate="2016-08-05T21:57:19.740" Title="Why doesn't the earth become superheated?" Tags="|atmospheric-radiation|earth-system|radiative-transfer|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8009" PostTypeId="2" ParentId="8008" CreationDate="2016-05-15T03:45:50.013" Score="4" Body="&lt;p&gt;A body has to emit as much thermal energy as it absobs to remain in thermal equilibrium. The Earth has been doing the same since  its formation, i.e, it absorbs solar  shorwave radiation by its atmosphere, solid earth and water body, and releases it in the form of longwave radiation. The amount that is released has to be equal to the amount that is absorbed to maintain same temperature. However, due to much emission of greenhouse gases in to the atmosphere (or according to sceptics of such concept due to solar activity, volcanic emission), some amount that the Earth has to release is absorbed by the gases in the atmosphere and are causing the Earth to warm by few degrees every year.   &lt;/p&gt;&#xA;" OwnerUserId="4877" LastEditorUserId="4877" LastEditDate="2016-05-15T03:50:54.070" LastActivityDate="2016-05-15T03:50:54.070" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8010" PostTypeId="2" ParentId="8008" CreationDate="2016-05-15T17:41:17.713" Score="2" Body="&lt;p&gt;The hotter the Earth gets the more it re-radiates energy back into space.You can see a tiny fraction of this energy by looking at the new moon. The feint glow is just a small part of the re-radiated spectrum.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The long term differential between incoming and outgoing energy is what is causing global warming. It isn't 'a few degrees (Centigrade) every year'. It is currently in the order of about 1.5 degrees per century. That's because of the following reason:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Initially, the carbon dioxide makes Earth emit less radiation than it's receiving. That heats up the air until the oceans are sucking heat out of the air at the same rate as it's being heated by radiation. That process is slowly warming the oceans so they're suck heat out of the air slower so Earth will get hotter. As a result of the higher temperature, the ground will emit radiation at as fast a rate as it's absorbing radiation from the sun and re-absorption from the carbon dioxide. The reason the average temperature is rising is because the amount of Carbon dioxide was increasing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Notwithstanding some diehard skeptics (who refuse to entertain the facts) the effect of greenhouse gasses in raising the global temperature is now so well verified as to be beyond doubt. Yes, variation in insolation rates and vocanic emissions also plays a relatively minor role, but cannot possibly explain all the evidence of global warming.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4846" LastEditDate="2016-08-05T21:57:19.740" LastActivityDate="2016-08-05T21:57:19.740" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8011" PostTypeId="1" AcceptedAnswerId="8013" CreationDate="2016-05-15T20:22:56.543" Score="3" ViewCount="402" Body="&lt;p&gt;From the answers from an earlier question, I learned that most of the solar radiation gained by the earth system (atmosphere, surface, and inner mass) is re-radiated back into space in the form of infra-red. This balance of incoming solar radiation and outgoing infra-red radiation depends on the earth system's infra-red radiation 'equation' - that is, how it takes 'in' the various forms of solar radiation and converts them into infra-red. At least, that's the best I can make out of this article &lt;a href=&quot;http://earthobservatory.nasa.gov/Features/EnergyBalance/page4.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth's Energy Budget&lt;/a&gt; and this accompanying chart.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PmbNR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PmbNR.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is what are the principal components of this 'equation'? I imagine the percentage of water in the atmosphere and on the surface of the earth, the mean absorptive ability of the non-water surfaces of the earth, and, what is most mysterious to me, what is the 'factor' of infra-red production by different surface materials. I imagine this is all highly technical and finely detailed in large elaborate models, but are there 'big levers' that represent most of the infra-red radiative effect? Where I am 'headed with' this, of course, is if there is a practical way to increase this radiation back to space that can make a positive difference on global warming (ie net positive radiation into space after accounting for increased greenhouse gases back radiation)? And I imagine there is not, given we are not trying that.&lt;/p&gt;&#xA;" OwnerUserId="5983" LastActivityDate="2018-03-14T20:34:22.050" Title="What are the major contributors to the amount of infra-red emitted by the earth?" Tags="|atmospheric-radiation|radiative-transfer|greenhouse-gases|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8013" PostTypeId="2" ParentId="8011" CreationDate="2016-05-16T06:38:02.040" Score="3" Body="&lt;p&gt;Q: What radiates energy back into space?&lt;br&gt;&#xA;A: anything above absolute zero temperature. That is, absolutely everything, according to the Stephan-Boltzman's law: &#xA;$$W = \sigma T^4$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where $\sigma$ is the Stephan-Boltzman constant and $T$ is the absolute temperature. So of course, volcanoes, steel foundries, forest fires, etc emit a disproportionate amount of energy, but the vast majority of radiant IR energy is just from everyday objects - such as me and you. Some insects, such as honey bees, which can see in the infra red, rely upon this radiant energy to find their pollen. Without this background radiant energy the world would feel a lot colder than it actually is. &#xA;So the main contributor to the infrared is nothing special - just the equatorial regions generally. One might also add a few ephemeral mid-latitude high temperature anomalies caused by the ocean-continent configuration, and transient effects of Rayleigh waves. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="6298" LastEditDate="2018-03-14T20:34:22.050" LastActivityDate="2018-03-14T20:34:22.050" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8014" PostTypeId="2" ParentId="8011" CreationDate="2016-05-16T10:56:37.840" Score="4" Body="&lt;p&gt;It depends on the wavelength.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tHwXg.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tHwXg.jpg&quot; alt=&quot;Most absorbing species&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The figure shows the most absorbing species between 6 and 16 µm for a U.S. standard tropical &lt;em&gt;atmosphere&lt;/em&gt; (&lt;strong&gt;Note: this figure does NOT include the Earth's surface!&lt;/strong&gt;).  Absorption data is taken from Anderson et. al (1986) and simulations are performed with the open-source &lt;a href=&quot;http://radiativetransfer.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atmospheric Radiative Transfer Simulator&lt;/a&gt; (ARTS; Eriksson et al., 2011).  The plotting was carried out with LaTeX and &lt;a href=&quot;http://pgfplots.sourceforge.net/&quot; rel=&quot;nofollow noreferrer&quot;&gt;pgfplots&lt;/a&gt;.  ARTS is open-source and includes the Anderson et al. data, so you can try different wavelengths for yourself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Depending on wavelength, we have dominant absorption from H₂O, O₃, CO₂, N₂O, CH₄, and others.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have also uploaded a &lt;a href=&quot;http://www.met.reading.ac.uk/~yw910419/spectrum_with_hirs_tropical.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;PDF version&lt;/a&gt; (PDF, 117.68 mm × 228.21 mm, 5.1 MiB) for higher-resolution viewing.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2016-05-17T13:11:18.577" LastActivityDate="2016-05-17T13:11:18.577" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8015" PostTypeId="2" ParentId="8011" CreationDate="2016-05-16T21:52:19.177" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;What is most mysterious to me, what is the 'factor' of infra-red production by different surface materials.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In asking about different surface materials, you are missing the big picture. If you want to understand global warming, simply look at the big picture you provided in the question. The Earth's surface receives more than twice as much energy in the form of thermal radiation from the atmosphere and clouds than it receives directly as sunlight. It's the greenhouse gases you need to focus on, not surface materials.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;My question is what are the principal components of this 'equation'?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It's the greenhouse gases in the air. Once again, look at the image you supplied in the question. Most of the outgoing radiation is emitted by the atmosphere and by clouds. Only 17% of the outgoing energy comes directly from the ground. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nitrogen and oxygen (the majority of the atmosphere) are diatomic compounds that don't absorb or emit thermal radiation very well. The multi-atomic compounds in the atmosphere on the other hand are efficient absorbers and emitters of thermal radiation.  Water vapor (H&lt;sub&gt;2&lt;/sub&gt;O) is a very powerful greenhouse gas, but it's self-regulating. Water vapor doesn't last very long in the atmosphere. It tends to condense and fall back to Earth as rain or snow. In addition to water vapor, there are long-lived greenhouse gases such as carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) and methane (CH&lt;sub&gt;4&lt;/sub&gt;) that stay in the atmosphere for a long time.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is there a practical way to increase this radiation back to space that can make a positive difference on global warming?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Sure. Reduce the manmade greenhouse gases in the atmosphere. The cause of anthropogenic global warming is the huge amount of greenhouse gases that humanity has put into the atmosphere in the last few hundred years.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2016-05-16T21:52:19.177" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8016" PostTypeId="1" AcceptedAnswerId="8017" CreationDate="2016-05-18T12:36:11.323" Score="5" ViewCount="840" Body="&lt;p&gt;When an earthquakes' focus is below the sea bed, is the epicenter given as a point on the oceans' surface at mean sea level, or as a point on the sea bed?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is some ambiguity in the term 'earths surface' here that is causing confusion in the English Language Learners sister site, which I'm hoping the experts here can clear up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm using the definition of epicenter found here. &#xA;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/2100/is-the-epicenter-always-directly-above-the-hypocenter/&quot;&gt;Is the epicenter always directly above the hypocenter?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5995" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-05-18T14:37:35.453" Title="Epicenter of earthquake at sea - is it a point on ocean surface or sea bed?" Tags="|earthquakes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8017" PostTypeId="2" ParentId="8016" CreationDate="2016-05-18T14:37:35.453" Score="5" Body="&lt;p&gt;Technically the depth is distance below the ocean floor, but bear in mind that unless there happens to be a cluster of seismometers close to the earthquake (unlikely in the ocean environment), the accuracy of depth estimates is only approximate. If you look at the table of earthquake depths in, for example, the Tonga Trench, you will see a few really deep earthquakes and many times more 'shallow earthquakes' at a nominal depth of 10 km - meaning 'shallow-ish'.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-05-18T14:37:35.453" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8019" PostTypeId="1" CreationDate="2016-05-19T07:36:17.980" Score="4" ViewCount="101" Body="&lt;p&gt;I am posting an algorithm (more of a procedure description) and I request a review of the correctness of the algorithm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Goal - To bring in scalar field values such as temperature, geopotential height, surface pressure, specific humidity found in a NOAA reanalysis file(typically &lt;a href=&quot;https://en.wikipedia.org/wiki/Gaussian_grid&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gaussian grid&lt;/a&gt;) into a rotated lat lon grid.This algorithm does &lt;strong&gt;NOT&lt;/strong&gt; apply to vector field values such as zonal and meridional velocities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given the following inputs- &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;latitude of the rotated north pole&lt;/li&gt;&#xA;&lt;li&gt;longitude of the rotated north pole&lt;/li&gt;&#xA;&lt;li&gt;latitude of the geographical north pole&lt;/li&gt;&#xA;&lt;li&gt;longitude of the geographical north pole&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Step 1 - Given the four input values use the following public routines available to transform coordinates in global Gaussian grid to rotated lat lon grid&#xA;&lt;a href=&quot;https://github.com/thiasB/unrotMe/blob/master/geo2rot.f90&quot; rel=&quot;nofollow noreferrer&quot;&gt;phi2phirot and rla2rlarot&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Step 2 - Since these are scalar field values there are no transformation equations for Temperature, Surface Pressure, Geopotential height and Specific Humidity. They remain unchanged to a change of coordinate systems( &lt;a href=&quot;https://en.wikipedia.org/wiki/Scalar_field&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scalar Fields unchanged&lt;/a&gt;. However the positions of the scalar field values would now be different(change of origin).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;NOTE&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am aware that there is a similar question on GIS SE - &lt;a href=&quot;https://gis.stackexchange.com/questions/64210/transforming-regular-lat-lon-to-rotated-lat-lon&quot;&gt;Transforming from regular lat lon to rotated lat lon&lt;/a&gt; they use a different approach by transforming first to Cartesian and then transforming back into lat lon. The public routines that I cite do not require a transformation to Cartesian first. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lauritzen, P. H., C. Jablonowski, M. A. Taylor, and R. D. Nair (2010), Rotated Versions of the Jablonowski Steady-State and Baroclinic Wave Test Cases: A Dynamical Core Intercomparison, J. Adv. Model. Earth Syst., 2, 15, doi:10.3894/JAMES.2010.2.15&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorUserId="-1" LastEditDate="2017-04-13T12:33:47.360" LastActivityDate="2016-05-19T17:29:37.023" Title="Algorithm confirmation for bringing in scalar field values from Gaussian grid to rotated lat lon grid" Tags="|data-formats|geospatial|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8021" PostTypeId="5" CreationDate="2016-05-19T09:55:24.487" Score="0" Body="&lt;p&gt;Please see the full homework policy &lt;a href=&quot;http://meta.earthscience.stackexchange.com/questions/316/how-do-i-ask-homework-questions-on-earth-science-stack-exchange/317#317&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2570" LastEditorUserId="2570" LastEditDate="2016-05-20T12:55:32.693" LastActivityDate="2016-05-20T12:55:32.693" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8022" PostTypeId="4" CreationDate="2016-05-19T09:55:24.487" Score="0" Body="If your question is part of your high school or college/university homework, please use this tag. Do not use this as the only tag on a question. It signifies that instead of a direct answer, care should be taken to explaining the steps to the solution, preferably sticking to just giving helpful, conceptual hints. This tag may be applied to questions which are not homework but are similar to a homework problem." OwnerUserId="2570" LastEditorUserId="2570" LastEditDate="2016-05-20T12:55:22.413" LastActivityDate="2016-05-20T12:55:22.413" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8023" PostTypeId="1" CreationDate="2016-05-20T05:34:52.790" Score="4" ViewCount="910" Body="&lt;p&gt;Is porphyritic texture always indicative of a 2 stage cooling process? Can't the phenocrysts and groundmass be formed at the same time depending upon the chemical constituents forming the rock? The groundmass being made up of constituents least in proportion and the phenocrysts being made up of the constituent in greatest proportion? &lt;/p&gt;&#xA;" OwnerUserId="6005" LastEditorUserId="725" LastEditDate="2016-05-20T21:43:49.087" LastActivityDate="2016-05-20T22:23:21.920" Title="Is porphyritic texture always indicative of a 2 stage cooling process?" Tags="|geology|geochemistry|mineralogy|petrology|igneous|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8024" PostTypeId="1" AcceptedAnswerId="8025" CreationDate="2016-05-20T10:08:38.207" Score="7" ViewCount="4710" Body="&lt;p&gt;I live in San Diego, CA, and surfers capitalize on dawn hours because the offshore (seaward) winds help &quot;hold up&quot; the waves, &lt;em&gt;i.e.&lt;/em&gt; prevent them from crashing before the surfer gets to ride it a while.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm only a beginner, but when I went to Korea, I met surfers from Santa Cruz, CA and Tianjin, China, who said it's the same everywhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why does this happen?&lt;/p&gt;&#xA;" OwnerUserId="6007" LastEditorUserId="6007" LastEditDate="2019-04-04T08:09:51.060" LastActivityDate="2019-04-04T08:09:51.060" Title="Why does wind blow offshore in the morning?" Tags="|meteorology|wind|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="8025" PostTypeId="2" ParentId="8024" CreationDate="2016-05-20T17:57:07.707" Score="11" Body="&lt;p&gt;The phenomenon you describe is denoted as a land breeze. It is caused by a difference between the sea surface temperature and the land surface temperature.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Surface Temperature&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;During day time the surface temperature at land rises faster than the sea surface temperature, whereas during night time the land surface cools faster than the sea surfaces. As a result, the sea surface temperature is higher than the land surface temperature in the morning.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Formation of the Breeze&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The sea surface heats the air above the sea stronger than the land surface does with the air above land. The warmer air masses above the sea rise to higher altitudes yielding a low pressure region. As a result, the colder air masses from above the land 'travel' to the low pressure region above the sea. This 'traveling' of air masses is wind: wind, which blows from the land to the sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a nice Figure from &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Diagrama_de_formacion_de_la_brisa-breeze.png&quot; rel=&quot;noreferrer&quot;&gt;Wikimedia Commons&lt;/a&gt; describing the sea breeze (A, evening/afternoon) and the land breeze (B, morning). The Figure was provided by &lt;a href=&quot;https://commons.wikimedia.org/wiki/User_talk:Corso&quot; rel=&quot;noreferrer&quot;&gt;Jesús Gómez Fernández&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4NWCd.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4NWCd.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Shower Curtain Example&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;If you shower in a shower with a shower curtain, you might experience that the lower end of the curtain moves towards your legs. The physical processes are similar: The warm shower water heats the air within the shower. The warm air rises which causes a low pressure region at the bottom of the shower. The air is colder at the bottom of the room outside the shower which leads to a high pressure system. The air from the high pressure system (bottom outside the shower) 'tries' to flow towards the low pressure system (bottom inside the shower) which moves the bottom end of the curtain towards you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This example works only if the room temperature in the bathroom outside the shower is not too warm/hot.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastEditorUserId="5594" LastEditDate="2016-05-20T18:04:18.740" LastActivityDate="2016-05-20T18:04:18.740" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8026" PostTypeId="2" ParentId="8023" CreationDate="2016-05-20T22:23:21.920" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is porphyritic texture always indicative of a 2 stage cooling process?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not necessarily. While it is a nice simplification for undergrad textbooks and it nicely explains phenocrysts in some simple basalts, there is much more to it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Availability of chemical constituents&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Can't the phenocrysts and groundmass be formed at the same time depending upon the chemical constituents forming the rock? The groundmass being made up of constituents least in proportion and the phenocrysts being made up of the constituent in greatest proportion?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In, principle, yes. Think of a granitic porphyry rock with huge feldspars and tiny zircon, apatite and oxides (magnetite, ilmenite, etc) in the groundmass. It could very well be that the feldspars are huge because the rock was rich in Na, Ca, K, Al and Si and it had little Zr, P, Ti and Fe&lt;sup&gt;3+&lt;/sup&gt;, as you would expect from a granite. Even if all minerals were crystallising together, the minerals with the trace components will not grow any larger because there is simply not enough of the elements that make them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Visual bias&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even if the rock looks porphyrytic, it may not be. Rocks with equally distributed grain size (also called seriate) may sometimes appear to be composed of phenocrysts and groundmass because this is what our brain sees. A seriate rock will have large and small crystals, and usually you will have lots of small crystals sitting just next to the big ones. Our brain tends to ignore the fact that the big ones actually come in all sizes, medium and larger.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Growth rate&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It was mentioned in the comments that &quot;&lt;em&gt;Crystal size is essentially a function of how long the crystal has been growing&lt;/em&gt;&quot;. This is mostly true for a specific crystal, in a known cooling rate, in a defined chemical magma composition, when it perfectly obeys thermodynamic rules, etc. In real natural systems this is not always the case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For crystals to grow, elements have to be removed from the silicate melt structure and attached to an existing crystal. What if there is no crystal yet? Usually, the formation of crystal nuclei requires a certain amount of undercooling of the silicate melt (up to a few tens of degrees, depending on conditions). Crystals can also nucleate on other minerals or vapour bubbles in the magma (just like bubbles in beer nucleate on the glass and not somewhere in the beer itself).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gxrCD.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gxrCD.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;sup&gt;source: &lt;a href=&quot;http://www.tulane.edu/~sanelson/eens212/textures_igneous_rocks.htm&quot; rel=&quot;noreferrer&quot;&gt;http://www.tulane.edu/~sanelson/eens212/textures_igneous_rocks.htm&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, temperature ideal for nucleation is not always ideal for crystal growth. So in this case, you will end up having lots of small crystals. This varies for different minerals, so one mineral may be in the &quot;growth&quot; field while another will be in the &quot;nucleation&quot; field. This will cause two different mineral sizes as the same time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Dynamic magma chambers&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recent research shows that our view of a single magma chamber that crystallises slowly or erupts is basically wrong. There are abundant processes that mix and mingle magmas, inject magmas to other magmas, and this sort of stuff. Think of a shallow magma chamber under a volcano that has crystallising clinopyroxene and has some amount of volatiles (CO&lt;sub&gt;2&lt;/sub&gt;, H&lt;sub&gt;2&lt;/sub&gt;O) dissolved in it. This magma is sitting there minding its own business, when suddenly a fresh hot mafic magma is injected from below. Our pyroxene phenocryst-bearing magma is now heated, expands and tries to escape upwards. It decompresses while doing so, nucleating bubbles of gas. The magma is also very undercooled and undersaturated with respect to olivine, so this olivine now crystallises in abundant tiny crystals on the bubbles. In this case, the groundmass actually crystallises when the magma is heated, not when the magma is cooled. Note that this is only an example, not all rocks that look like this formed in the way I described, but it's a possibility.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is also true for plutonic rocks where the mineral assemblage you see rarely corresponds to the exact composition of the magma from which it crystallised. Crystals can and do move around in magma chambers. This can bring together crystals of different sizes into one place.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Large crystals may not necessarily crystallise from magma&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Phenocrysts may nucleate and grow rapidly in water bubbles that exist in the magma, during magmatic conditions (so I'm not talking about zeolites). While the minerals are those you would expect to see in the solid rock after magma solidified, it was favourable for those crystals to grow in the coexisting bubble. This is one explanation (out of many) for the formation of Rapakivi granites.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-05-20T22:23:21.920" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8027" PostTypeId="1" AcceptedAnswerId="8030" CreationDate="2016-05-20T23:39:22.593" Score="6" ViewCount="3449" Body="&lt;p&gt;I like to walk my dog along a beach, but in medium to high tide, there is no beach at all, as the water reaches the bluffs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MZcdg.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MZcdg.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The thing is, the height of the sand seems to vary drastically as well. Sometimes, I'll be fine walking at medium-high tide because so much sand has deposited that there's still a path. (I first noticed this when I couldn't find the usual caves and crevices along my walk—I realized they were buried in six feet of sand.) Other times, even at &lt;em&gt;low&lt;/em&gt; tide some of the waves reach my ankles, even the cliffs. In those times, I also end up walking on rock instead of sand at parts, and can see this rockbed extend out toward the break.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What brings the sand in or out?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know the obvious answer is the incoming or outgoing tide, but I've walked at low tide when the sand was very, very high (therefore, didn't flush out with the tide), such that the beach seemed gigantic. I've also gone surfing in high tide when I couldn't stand on my feet near the bluffs, because the sand never came in. And I don't think it can be rip currents since the sand height is more or less uniform throughout the beach.&lt;/p&gt;&#xA;" OwnerUserId="6007" LastEditorUserId="2570" LastEditDate="2016-05-23T12:25:03.700" LastActivityDate="2016-07-07T21:00:11.720" Title="What factors bring sand into or out of the beach?" Tags="|ocean|sedimentology|coastal|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8028" PostTypeId="5" CreationDate="2016-05-21T10:57:36.777" Score="0" Body="&lt;p&gt;Details about the global weather model GFS can be found at the NOAA &lt;a href=&quot;http://www.emc.ncep.noaa.gov/index.php?branch=GFS&quot; rel=&quot;nofollow&quot;&gt;webpage&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2016-05-21T21:03:06.213" LastActivityDate="2016-05-21T21:03:06.213" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8029" PostTypeId="4" CreationDate="2016-05-21T10:57:36.777" Score="0" Body="Global Forecast System" OwnerUserId="124" LastEditorUserId="124" LastEditDate="2016-05-21T21:03:13.683" LastActivityDate="2016-05-21T21:03:13.683" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8030" PostTypeId="2" ParentId="8027" CreationDate="2016-05-21T13:55:53.807" Score="7" Body="&lt;p&gt;The amount of sand on the beach at any one time is a dynamic quasi-equilibrium between a whole raft of processes. These include wave power, frequency and direction, seabed angle, longshore drift, rips and undertow, wind strength, direction and continuity, fetch, coastal geomorphology, sediment availability, offshore currents, and probably other variables. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The entire system is too complex to summarize here, so I recommend Robin Davidson-Arnott's excellent book: 'An introduction to coastal processes and geomorphology'. Cambridge University Press, 2010.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-05-21T13:55:53.807" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8031" PostTypeId="1" CreationDate="2016-05-21T18:01:59.977" Score="0" ViewCount="37" Body="&lt;p&gt;As far as I know the temperature of the air depends on how fast the airmolecules are moving. But what is the increase of speed (in km/h) of those are molecules?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastActivityDate="2016-07-05T02:38:57.180" Title="How much faster are airmolecules going when the temperature raise from 15 to 25 degrees C?" Tags="|climate|" AnswerCount="1" CommentCount="4" ClosedDate="2016-05-22T10:21:55.880" ContentLicense="CC BY-SA 3.0" />
  <row Id="8033" PostTypeId="1" AcceptedAnswerId="8034" CreationDate="2016-05-21T18:23:41.227" Score="5" ViewCount="1902" Body="&lt;p&gt;My textbook says that the specific gravity is &quot;the ratio of the mass of a mineral compared with the mass of an equal volume of water.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this any different to density? If so, how? If not, why does it have its own name in geology?&lt;/p&gt;&#xA;" OwnerUserId="3109" LastEditorUserId="-1" LastEditDate="2016-05-22T10:22:10.367" LastActivityDate="2016-05-22T10:22:10.367" Title="Is there a difference between Density and Specific Gravity?" Tags="|geology|measurements|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8034" PostTypeId="2" ParentId="8033" CreationDate="2016-05-21T19:30:45.877" Score="9" Body="&lt;p&gt;It is different to density but they are closely related. This is easily seen by considering the dimensions of the two quantities (side note: &lt;em&gt;always&lt;/em&gt; consider the dimensions of quantities - it is invariably useful).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you read your definition carefully you will realise that specific gravity is defined as the ratio of the density of the material to that of water. $$\mathrm{SG = \frac{\rho_{sample}}{\rho_{water}}}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Historically I suspect that specific gravity was used rather than density because it is easy to measure by measuring the mass of the displaced water when you place the sample into a jar of water, and the mass of the sample itself. You don't actually need to know the density of water in order to calculate the specific gravity.&lt;/p&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2016-05-21T19:30:45.877" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8036" PostTypeId="1" CreationDate="2016-05-22T02:03:03.243" Score="1" ViewCount="120" Body="&lt;p&gt;For the past 50 million years, India has been colliding with mainland Asia, creating the Himalayan mountain range.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's not an issue of &lt;strong&gt;&lt;em&gt;if&lt;/em&gt;&lt;/strong&gt; the Himalayas would stop rising, but &lt;strong&gt;&lt;em&gt;when&lt;/em&gt;&lt;/strong&gt;.  Articles of the past months have said that the range would stop rising in the best guess of 20 million years, not because of gravity, but because of how the mantle influences the movements of the landmasses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But what the articles never say is what would happen when the Himalayas stop rising in the distant future.  How would the topography of Asia be affected?  How would Tibet react?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastActivityDate="2016-05-22T05:57:02.763" Title="What Happens When India Stops Hitting Asia" Tags="|mountains|tibetan-plateau|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8037" PostTypeId="2" ParentId="8033" CreationDate="2016-05-22T05:25:51.300" Score="0" Body="&lt;p&gt;It's simple. Specific Gravity is dimensionless. It's just a ratio.&#xA;Density is dimensional, such as grams per cubic centimeter, kilograms per litre, tonnes per cubic metre, etc. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-05-22T05:25:51.300" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8038" PostTypeId="2" ParentId="8036" CreationDate="2016-05-22T05:48:33.637" Score="3" Body="&lt;p&gt;You are correct in that, sooner or later (and nobody can say just when) the Indian plate will stop crashing into the Eurasian plate, and the the two plates will effectively fuse into a single plate. The underlying mantle convection is likely to continue for a few million years, tending to displace the combined plate further northward, probably with a component of anti-clockwise rotation, which might result in a few micro-continental fragments breaking off. The Yakutsk peninsular is one such possible candidate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Probably the single most important result will be the fate of the Himalayan chain. Again, the underlying mantle is likely to take a few million years to gain litho-static equilibrium, so seismic rumblings will continue, but probably with much less intense earthquakes than we have seen recently. Fluvial erosion is probably faster than you think. Within 20 million years, and possibly even in 10 million years, all of the great mountains will be worn down to a pale shadow of their former state. More and more rivers will break through from Tibet, and drain southwards. The Himalayas will become much less of a climatic barrier than they are now, such that the monsoonal air flow, and much of the moisture than it carries, will spill over into Central Asia. The main rivers that feed into the Ganges will carry less water. The climate of Central Asia will change dramatically, but it's difficult to predict exactly how. Currently the air flow from southern Europe is deflected southeasterly across Iran and the Gulf, being effectively blocked by the Central Asian mountains. As these mountains are eroded this airflow will become progressively less hindered, making west central Asia wetter, and the Arabian Gulf even drier than it is already.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Glaciers and snow topped mountains are already in rapid decline because of global warming. The ice will certainly be long-gone by the time the tectonic conveyor belt grinds to a halt. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The eroded debris will drain into the Bay of Bengal. The current effects of rising sea level will flood most of Bangladesh in the short term, but it will ultimately be reformed as erosion overtakes rising sea level. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for Tibet, one would expect a long period of erosion, mainly by deeply incised rivers dissecting the plateau, much as the Colorado River is cutting away at the Colorado plateau in North America; a process greatly aided by much increased rainfall. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2016-05-22T05:57:02.763" LastActivityDate="2016-05-22T05:57:02.763" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8039" PostTypeId="2" ParentId="8031" CreationDate="2016-05-22T06:17:06.113" Score="1" Body="&lt;p&gt;User LTK 4 is correct. The air molecule is moving 1.7% faster at 25&amp;deg;C.&#xA;Marijn can calculate the absolute velocities from the simple equation given in &lt;a href=&quot;http://www2.ignatius.edu/faculty/decarlo/surfacepower/pages/KineticTheoryOfGases.htm&quot; rel=&quot;nofollow&quot;&gt;http://www2.ignatius.edu/faculty/decarlo/surfacepower/pages/KineticTheoryOfGases.htm&lt;/a&gt; .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And yes, this is more physics than Earth Sciences.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="111" LastEditDate="2016-07-05T02:38:57.180" LastActivityDate="2016-07-05T02:38:57.180" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8040" PostTypeId="1" CreationDate="2016-05-22T09:36:05.367" Score="7" ViewCount="77" Body="&lt;p&gt;I have been analyzing the surface wave measurements taken from the location where the waves interact with both opposing and following currents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't understand why the peak frequency decreases when the waves interact with a strong opposing or following current. Can anyone help me understand that?&lt;/p&gt;&#xA;" OwnerUserId="6013" LastEditorUserId="192" LastEditDate="2016-05-22T22:28:47.327" LastActivityDate="2016-05-22T22:28:47.327" Title="Effects of currents on peak wave frequency" Tags="|ocean|waves|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8042" PostTypeId="1" CreationDate="2016-05-22T15:26:38.287" Score="11" ViewCount="25827" Body="&lt;p&gt;This video clip, &lt;a href=&quot;http://www.dailymail.co.uk/news/article-3576719/What-Workers-baffled-discovering-blowhole-desert-sends-sand-shooting-hundreds-feet-air-refuses-filled-in.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;Strange Hole in the desert Blows Sand into the air in Saudi Arabia&quot;&lt;/a&gt; (&lt;a href=&quot;https://www.facebook.com/brunei.islam/videos/1066764660047708/&quot; rel=&quot;nofollow noreferrer&quot;&gt;alternative link&lt;/a&gt;), shows a hole in the desert that erupts like a geyser, except with sand instead of water. It is apparently located in the Aljof area in the north of Saudi Arabia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The commenters on this video (and its duplicates) have come up with many conjectures, including:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;natural gas from a freshly-drilled mine&lt;/li&gt;&#xA;&lt;li&gt;a broken pipeline underneath.&lt;/li&gt;&#xA;&lt;li&gt;a pressure build up of certain gases, like methane.&lt;/li&gt;&#xA;&lt;li&gt;a fake video.&lt;/li&gt;&#xA;&lt;li&gt;seismic or volcanic activity.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Can anyone explain what this phenomena is?&lt;/p&gt;&#xA;" OwnerUserId="5320" OwnerDisplayName="NVZ" LastEditorUserId="5320" LastEditDate="2018-01-20T08:23:18.070" LastActivityDate="2018-01-20T08:23:18.070" Title="What is this &quot;hole&quot; that blows sand into the air?" Tags="|geology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8043" PostTypeId="1" AcceptedAnswerId="8046" CreationDate="2016-05-23T03:59:34.260" Score="13" ViewCount="1126" Body="&lt;p&gt;As I know, the Earth core is solid. This is known, because it conducts also transverse waves, while liquids conduct only longitudinal waves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But, how was it found? The inner core is in the outer core, which is liquid. Thus, it is inpermeable for the transverse waves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, any transverse wave originating in the crust, shouldn't be able to reach the core and vice versa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How could it been measured?&lt;/p&gt;&#xA;" OwnerUserId="6016" LastEditorUserId="2570" LastEditDate="2016-05-23T08:37:33.990" LastActivityDate="2016-05-23T08:37:33.990" Title="How is known that the Earth core is solid?" Tags="|geophysics|seismology|core|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8046" PostTypeId="2" ParentId="8043" CreationDate="2016-05-23T08:28:55.533" Score="13" Body="&lt;p&gt;This is a good observation. The reason we can measure S-wave (transverse) propagation in the inner core is because &lt;strong&gt;P-waves can set up S-waves and vice versa.&lt;/strong&gt; When an S-wave hits the mantle-outer core boundary at an angle it has a vibration component which is normal to the boundary and this sets up a P-wave in the liquid inner core. The opposite happens at the outer core-inner core boundary, where the P-wave at the boundary sets up an S-wave in the solid inner core. In this way, we can measure S-wave transmission through the inner core.&lt;/p&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2016-05-23T08:28:55.533" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8047" PostTypeId="1" CreationDate="2016-05-23T09:18:37.760" Score="1" ViewCount="200" Body="&lt;p&gt;I live in France.&#xA;Is it true that there are more occurrences of deep blue skies during spring. If yes why ?&#xA;Is it true also during autumn.&#xA;Thank you for answering&lt;/p&gt;&#xA;" OwnerUserId="6019" LastActivityDate="2016-05-23T14:51:54.673" Title="Pure blue sky in Spring" Tags="|meteorology|atmosphere|earth-observation|" AnswerCount="1" CommentCount="2" ClosedDate="2016-05-24T01:23:46.470" ContentLicense="CC BY-SA 3.0" />
  <row Id="8048" PostTypeId="1" CreationDate="2016-05-23T11:08:03.977" Score="2" ViewCount="499" Body="&lt;p&gt;If the moon reflects exactly the sun spectrum, then the blue photons part of the spectrum should scatter in the atmosphere during the night (assuming a perfect dark night sky). Why don't we see a bluish light during the night, the equivalent of a blue sky during the day ?&lt;/p&gt;&#xA;" OwnerUserId="6019" LastActivityDate="2017-12-29T06:55:53.600" Title="Rayleigh scattering from the moon light" Tags="|meteorology|atmosphere|climate|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8049" PostTypeId="1" AcceptedAnswerId="8050" CreationDate="2016-05-23T11:16:44.690" Score="5" ViewCount="18834" Body="&lt;p&gt;I want to understand the phenomena where water droplets after precipitation reaches to the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How much time does it take to become ground water or in other words how much time is taken by water to recharge the ground after rain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am assuming the water droplets falls in the plain having no concrete human constructions.&lt;/p&gt;&#xA;" OwnerUserId="5093" LastEditorUserId="2570" LastEditDate="2016-05-23T19:02:04.033" LastActivityDate="2016-05-23T19:02:04.033" Title="How much time does water takes to reach to the ground?" Tags="|hydrology|water|rainfall|groundwater|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8050" PostTypeId="2" ParentId="8049" CreationDate="2016-05-23T14:39:18.013" Score="4" Body="&lt;p&gt;It depends upon the hydraulic conductivity, the degree of saturation, and the depth to water table. Generally, water seeping down in the unsaturated zone moves very slowly. Assuming a typical depth to water table of 10 to 20 metres, the seepage time could be a matter of minutes in the case of coarse boulders, to months or even years if there is a lot of clay in fine sediment. Under saturated conditions, the water might move a lot faster. Other factors include the configuration of the wetting front, the unsaturated storage, temperature, and the hydraulic gradient. So basically, there is no simple answer - it's all a matter of the local hydrogeology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is no substitute for local measurement - water levels in an observation bore, in the case of water table conditions, or tensiometry in the case of the unsaturated zone.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-05-23T14:39:18.013" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8051" PostTypeId="2" ParentId="8049" CreationDate="2016-05-23T14:45:43.820" Score="3" Body="&lt;p&gt;Your question is difficult to answer because many factors will affect ground water recharge:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Soil porosity, which will be affected by soil pore space volumes,&#xA;soil cohesion (the distribution of clay &amp;amp; sand etc. within the soil matrix) and the presence of hydrophobic soil grains and minerals&lt;/li&gt;&#xA;&lt;li&gt;Soil moisture content&lt;/li&gt;&#xA;&lt;li&gt;Depth of the soil&lt;/li&gt;&#xA;&lt;li&gt;The presence or absence of water impervious strata, such a clays&lt;/li&gt;&#xA;&lt;li&gt;The presence or absence of ground fissures, faults or other&#xA;discontinuities that can allow water to be channelled through them&lt;/li&gt;&#xA;&lt;li&gt;The amount of rain that falls and surface evaporation rates&lt;/li&gt;&#xA;&lt;li&gt;The depth of the ground water table&lt;/li&gt;&#xA;&lt;li&gt;Drought affected soil may have soil grains that may need to be&#xA;hydrated, by absorbing some water, prior to letting surplus water&#xA;pass by them&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-05-23T14:45:43.820" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8052" PostTypeId="2" ParentId="8047" CreationDate="2016-05-23T14:51:54.673" Score="0" Body="&lt;p&gt;This is related to a similar question on April 29th in that the apparent colour of the sky is mainly caused by the absorption of different wavelengths of light by a wide range of atmospheric pollutants. I strongly suspect that if you compare the antecedent rainfall with the colour of the sky (in a given direction at a given time of day) you will find a marked correlation. The rain scrubs the atmosphere clean, so, facing away from the sun, you are likely to see a brighter blue after any period of significant rain.&lt;br&gt;&#xA;So what is the typical amount of rain in spring, summer, autumn and winter, in your part of France?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-05-23T14:51:54.673" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8053" PostTypeId="2" ParentId="4642" CreationDate="2016-05-23T17:59:42.837" Score="-1" Body="&lt;p&gt;Please read this article.  It explains the heavy metal separation from the wet process.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://dx.doi.org/10.1016/j.jrras.2014.01.001&quot; rel=&quot;nofollow&quot;&gt;http://dx.doi.org/10.1016/j.jrras.2014.01.001&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I believe the decay rate of thorium to radium in the uranium decay series is 77k years.  Therefore, however much radium/thorium/uranium you measure in a sample, it won't really change during your lifetime.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the United Nations Scientific Committee on the Effects of Atomic Radiation the normal concentration of uranium in soil is 300 μg/kg to 11.7 mg/kg.  It is found in most soils and rock naturally at highly varying concentrations.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Phosphate rock does not become enriched with uranium/thorium/radium until the extraction process separates and concentrates these metals.  When the phosphate rock is treated with sulfuric acid, the uranium and thorium become concentrated in the aqueous phase while radium concentrates into the gypsum.  A lot of other heavy metals also get incorporated into the phosphoric acid phase since most are soluble in dilute acid solutions.  I suppose these contaminants could be marketed as micronutrients in the phosphate fertilizer products.&lt;/p&gt;&#xA;" OwnerUserId="6023" LastEditorUserId="725" LastEditDate="2016-05-23T21:43:05.537" LastActivityDate="2016-05-23T21:43:05.537" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8054" PostTypeId="1" AcceptedAnswerId="8168" CreationDate="2016-05-23T21:52:12.027" Score="2" ViewCount="296" Body="&lt;p&gt;I'm trying to better understand &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydrological_code#United_States&quot; rel=&quot;nofollow&quot;&gt;the Hydrological Unit Code (HUC) system of the United States&lt;/a&gt;. I understand the basic hierarchy of it (HUC4, 6, 8, 12) and watersheds/drainage areas. Here's what I want to clarify:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A group of HUC8s can be within a single HUC6, because each HUC8 ultimately drains to the pour point of their parent HUC6. &lt;strong&gt;What separates one HUC8 from another HUC8 downstream of it, both within the same parent Hydrologic Unit?&lt;/strong&gt; I suspect the answer isn't the natural drainage area, because &lt;em&gt;the downstream HUC8 would contain the upstream HUC8 in its natural drainage area&lt;/em&gt; - that's based on me thinking that as you shift the discharge point you're examining further downstream, the drainage area you're examining increases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most concise, relevant explanation I've come across is from &lt;a href=&quot;https://enviroatlas.epa.gov/enviroatlas/DataFactSheets/pdf/Supplemental/Watershed.pdf&quot; rel=&quot;nofollow&quot;&gt;the USEPA's EnviroAtlas Data Fact Sheet on the subject&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A&#xA;  watershed  is &#xA;  defined  as  the&#xA;  geographic  a&#xA;  rea  within  the &#xA;  boundary&#xA;  of   a   drainage   divide.   Watershed   boundaries &#xA;  follow  the  highest  ridgeline  around  the  stream &#xA;  drainage &#xA;  area; &#xA;  the  bottom &#xA;  of  the  watershed  or  the  pour  point  is  the&#xA;  lowest point of the land &#xA;  area &#xA;  where water flows out of the &#xA;  watershed.&#xA;  Hydrologic   unit   boundaries   do   not   always &#xA;  surround    a    complete    watershed    but    may    delineate &#xA;  truncated portions of a larger watershed&#xA;  —&#xA;  for example, the &#xA;  mid-stem   of   a   larger&#xA;  stream   or   river   along   with   the &#xA;  tributaries&#xA;  in  that  area. &#xA;  Hydrologic  units  are &#xA;  generally &#xA;  synonymous   with   watersheds   when   their   boundaries &#xA;  include  all  the  source  area  contributing  surface  water  to&#xA;  a &#xA;  single   defined   outlet   point.   This   distinction   between &#xA;  watersheds and HUCs is important in the context of water &#xA;  resources   data   analysis   and   water   quality   monitoring, &#xA;  because  the  area  contributing  to  the  downstream  outlet &#xA;  point in a single HUC may extend beyond its boundaries in &#xA;  an  upstream  direction  to  include  a  number  of  other  sub-basin HUCs.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This still does not clarify exactly &lt;strong&gt;what separates one HUCx from another HUCx downstream of it, both within the same parent HUC?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="4789" LastEditorUserId="4789" LastEditDate="2016-05-24T14:55:36.247" LastActivityDate="2016-06-11T21:20:37.817" Title="What divides Hydrological Unit Code areas of the same level?" Tags="|hydrology|gis|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8055" PostTypeId="1" CreationDate="2016-05-23T22:11:12.987" Score="2" ViewCount="346" Body="&lt;p&gt;USGS stream gauges have an associated drainage area, but the associated &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydrological_code#United_States&quot; rel=&quot;nofollow noreferrer&quot;&gt;hydrologic unit&lt;/a&gt; listed by USGS is often different than the actual drainage area. &lt;strong&gt;How can one determine what hydrologic unit corresponds exactly with the drainage area of a stream gauge, and where applicable, vice versa &lt;em&gt;(...what stream gauge corresponds exactly with a hydrologic unit that is a watershed)&lt;/em&gt;?&lt;/strong&gt; I expect that this cannot be done for all HUC levels, but that it should be doable for certain HUC levels which are almost always actual drainage basins (e.g. HUC12s are almost always true watersheds with an average area of 40 square miles, so won't some of those line up with USGS gages of similar sized basins?)&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;To demonstrate the problem: let's say I'm trying to examine the properties of a watershed - a HUC12 - and want to see stream gauge data for it. To find stream gauge data, I'd go to the &lt;em&gt;USGS Water Resources&lt;/em&gt; site and hone in on the area of the watershed of interest - the issue is that many gauges have a Hydrologic Unit 8 listed on the gauge's Summary Information page that is different from the drainage area listed on that same page and from the watershed delineation one would get if starting with a DEM and the gauge's coordinates in GIS.&lt;br&gt;&#xA;That brings me back to my question in bold above - any guidance or clarification on finding paired USGS stream gauges and HUC's &lt;em&gt;that are drainage areas&lt;/em&gt; (since not all hydrologic units represent actual watersheds that can be gauged)?&lt;/p&gt;&#xA;" OwnerUserId="4789" LastEditorUserId="4789" LastEditDate="2018-07-12T17:37:35.263" LastActivityDate="2018-07-12T17:37:35.263" Title="How to determine associated USGS stream gauges with a watershed HUC?" Tags="|hydrology|gis|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="8057" PostTypeId="1" CreationDate="2016-05-24T01:33:25.500" Score="1" ViewCount="497" Body="&lt;p&gt;I am doing a school project and need to know...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Will the Earth's mantle or core ever cool? If so, how? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;" OwnerUserId="6021" LastActivityDate="2020-05-07T04:11:02.467" Title="Will the Earth's core cool?" Tags="|geophysics|temperature|" AnswerCount="1" CommentCount="3" ClosedDate="2016-05-24T11:07:25.513" ContentLicense="CC BY-SA 3.0" />
  <row Id="8058" PostTypeId="2" ParentId="7167" CreationDate="2016-05-24T05:35:18.883" Score="1" Body="&lt;p&gt;It's difficult but not impossible to model the Earth, Moon and Sun, but the scale is a bit tricky to get right if you try to build or draw it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we call the Moon's diameter = 1 moon unit, then, Earth's diameter is about 4 moon units.   Distance between Earth and Moon, about 110 units, Sun's diameter, about 400 units, and the big one, the Sun's distance to the earth, about 43,000 moon diameter units.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if the Moon is big enough to see, but still very small, say 1 mm, then the sun needs to be 40 cm in diameter (about 33% larger than a basketball) and 43 meters away. &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2016-05-24T05:35:18.883" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8059" PostTypeId="2" ParentId="8057" CreationDate="2016-05-24T05:37:44.827" Score="1" Body="&lt;p&gt;Yes. It's kept warm by slowly  decaying primordial radioactive elements. They are: Uranium (238) and Thorium (232). The half life of the first is 4.4 billion years, the second around 14 billion years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They heat the surface even to this date, and it's around 0.2K warmer than if they were absent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Owing to their continued decay, this temperature differential will decrease .&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Extension:&lt;/strong&gt; On the most popular &lt;a href=&quot;http://www.thenakedscientists.com/forum/index.php?topic=44643.5;wap2&quot; rel=&quot;nofollow noreferrer&quot;&gt;models&lt;/a&gt; (and David Hammen's comment :-) ), Uranium and Thorium are in the crust and   mantle, and not in the core. Despite that, their radioactive decay heats the Earth.&lt;/p&gt;&#xA;" OwnerUserId="6016" LastEditorUserId="2470" LastEditDate="2020-05-07T04:11:02.467" LastActivityDate="2020-05-07T04:11:02.467" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="8062" PostTypeId="1" AcceptedAnswerId="8066" CreationDate="2016-05-24T10:41:15.637" Score="6" ViewCount="154" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;An unknown mineral shows three distinct pleochroic colours. Explain what observations you need to make in order to decide which crystal system it belongs to.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;If it has three pleochroic colours this means that it must have a biaxial indicatrix and must therefore be orthorhombic, monoclinic or triclinic. In order to work out which one of these it is you need to work out the orientation of the indicatrix with respect to the crystallographic axes but I'm not sure how you can do this. You can measure the extinction angle with respect to things like cleavage but if it's an unknown mineral then you don't know how the cleavage is oriented with respect to the axes. How do you determine which direction the crystallographic axes are in using a petrographic microscope?&lt;/p&gt;&#xA;" OwnerUserId="2570" LastEditorUserId="20" LastEditDate="2016-05-24T20:44:09.100" LastActivityDate="2016-05-25T08:01:43.953" Title="Identifying trichroic crystal systems" Tags="|mineralogy|homework|crystallography|petrography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8063" PostTypeId="1" CreationDate="2016-05-24T21:12:35.107" Score="4" ViewCount="294" Body="&lt;p&gt;While reading the topic &quot;Monsoon&quot; in Aguado's Understanding Weather and Climate, I read this line &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;During winters... Air flows down the southern slope of the Himalayan&#xA;  Mountains due to more rapid cooling over land than over&#xA;  the Indian Ocean. This flow is enhanced by a portion of the&#xA;  jet stream flowing along the southern flank of the mountain&#xA;  range. Interactions between the jet stream and mountains&#xA;  cause convergence in the upper troposphere, which leads to&#xA;  sinking air that gets forced southward.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It is talking about the Subtropical Westerly Jet Stream's southern branch flowing along the southern Himalayas, but how does it cause convergence in upper troposphere? And how the convergence in upper troposphere leads to sinking of air?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the same topic, after few lines, while explaining the situation in summer season it is mentioned that &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The situation changes abruptly during late spring or early&#xA;  summer....Aloft is&#xA;  an easterly jet stream, with often divergent motion promoting&#xA;  uplift.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Why this Easterly jet stream has divergent motion, how it differs from the SubTropical Westerly Jet Stream in this characteristic? And again the same question, how does divergent motion in upper troposphere cause uplift? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since I couldn't find anything useful related to Jet Streams and convergence/divergence it would be helpful if someone could provide exact mechanism. &lt;/p&gt;&#xA;" OwnerUserId="2756" LastActivityDate="2016-05-24T21:12:35.107" Title="How does the interaction between Subtropical Westerly Jet Stream and Himalayas causes subsidence of air?" Tags="|meteorology|monsoon|jet-stream|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8064" PostTypeId="5" CreationDate="2016-05-25T07:05:06.667" Score="0" Body="&lt;p&gt;For questions related to Geographic Information Systems: any digital tool that is designed to obtain, edit, analyze, and present spatially organized data. Question asked here should be specific to Earth Science.&lt;/p&gt;&#xA;&lt;p&gt;For questions concerning GIS packages and systems it may be better to ask the question on the Stack Exchange site dedicated site for GIS questions, &lt;a href=&quot;https://gis.stackexchange.com/&quot;&gt;gis.stackexchange.com&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="-1" LastEditorUserId="2470" LastEditDate="2022-02-16T08:55:21.920" LastActivityDate="2022-02-16T08:55:21.920" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="8065" PostTypeId="4" CreationDate="2016-05-25T07:05:06.667" Score="0" Body="For questions related to Geographic Information Systems: any digital tool that is designed to obtain, edit, analyze, and present spatially organized data.  However, please note, a dedicated site for GIS questions, gis.stackexchange.com, might be a better place to ask GIS-related questions." OwnerUserId="124" LastEditorUserId="2470" LastEditDate="2022-02-16T08:55:21.920" LastActivityDate="2022-02-16T08:55:21.920" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="8066" PostTypeId="2" ParentId="8062" CreationDate="2016-05-25T08:01:43.953" Score="1" Body="&lt;p&gt;Theoretical answer:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You need to measure extinction angles. If it is always extinct when aligned to cleavage or crystal faces, then it is orthorhombic. If it sometimes aligns and the colour is consistent, it's monoclinic. Otherwise it's triclinic. You do not need to know how cleavage is oriented with respect to the axes in advance because there very few orthorhombic minerals with oblique cleavage (if any at all).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Practical answer (and a rant):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have no idea why is this still taught in 2016. The motivation of this thing is to know optical properties so you can derive chemical information from them. These days it's probably cheaper and faster to put the sample in XRD or SEM-EDS to know what it is. Even when three colours exist, it is usually very subtle and you will need a lot of self-convincing to see the third colour on its own and not as a combination of the other two. Then there's the issue of a real mineral actually having a proper crystal shape and cleavage (good luck doing this on a 10 micrometre wide anhedral crystal in a thin section).&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-05-25T08:01:43.953" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8067" PostTypeId="1" AcceptedAnswerId="8069" CreationDate="2016-05-26T04:23:55.700" Score="12" ViewCount="3141" Body="&lt;p&gt;In WRF application, nested domain has always been used for weather/air quality modeling for the place of interest in a better resolution. The figure below illustrates this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5mQC0.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5mQC0.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have noticed that the ratio of grid resolution between outer (coarser) domain and inner (finer) domain are always set at 3:1 ratio.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any reason in the aspects of physical process or computation? Is the ratio of 3:1 helpful for the interaction between the boundary?&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="192" LastEditDate="2016-05-26T15:22:32.077" LastActivityDate="2016-05-26T15:22:32.077" Title="Why is WRF most often configured at 3:1 nesting ratio?" Tags="|meteorology|atmosphere|models|atmosphere-modelling|wrf|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8068" PostTypeId="2" ParentId="7390" CreationDate="2016-05-26T11:49:15.483" Score="2" Body="&lt;p&gt;I have recently had to deal with the same problem and tackled it in Matlab,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If it helps, here's a link to it on the file exchange&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://au.mathworks.com/matlabcentral/fileexchange/57349-nagyprism-x1-x2-y1-y2-h-rho-&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://au.mathworks.com/matlabcentral/fileexchange/57349-nagyprism-x1-x2-y1-y2-h-rho-&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is the code:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;% A function to perform terrain corrections using the Nagy &#xA;% prism formula. &#xA;% To calculate the terrain correction for a block of topography&#xA;% with coordinates (x1,y1) (x2,y1) (x1,y2) (x2,y2) in the x,y plane and&#xA;% height h.&#xA;%......................................&#xA;%............___________&#xA;%.........../!........./!?.............&#xA;%........../_!________/.!?.............&#xA;%..........!.!.......!..!h ............&#xA;%..........!.!.......!..!?.............  &#xA;%..........!.!.......!..!?.............  &#xA;%..........!.!.......!..!?.............  &#xA;%..........!.!(x1,y2)!..!(x2,y2).......  &#xA;%..........!./.......!./............... &#xA;%(x1,y1)...!/________!/(x2,y1).........&#xA;% &#xA;% with density rho;&#xA;% the terrain correction T is given by&#xA;% T = nagyprism(x1,x2,y1,y2,h,rho)&#xA;% &#xA;% The function can handle vectors of coordinates so that correction&#xA;% for mutiple pieces of terrain can also be calculated&#xA;function [terrc] = nagyprism(x1,x2,y1,y2,h,rho)&#xA;twopiG = 0.0419; % for g in mgal, h in m and rho in Mg/m3&#xA;G=twopiG/(2*pi);&#xA;fac11=sqrt(x1.^2+y1.^2);&#xA;fac11h=sqrt(x1.^2+y1.^2+h.^2);&#xA;fac12=sqrt(x1.^2+y2.^2);&#xA;fac12h=sqrt(x1.^2+y2.^2+h.^2);&#xA;fac21=sqrt(x2.^2+y1.^2);&#xA;fac21h=sqrt(x2.^2+y1.^2+h.^2);&#xA;fac22=sqrt(x2.^2+y2.^2);&#xA;fac22h=sqrt(x2.^2+y2.^2+h.^2);&#xA;fac2h=sqrt(y2.^2+h.^2);&#xA;fac1h=sqrt(y1.^2+h.^2);&#xA;y2h=y2.^2+h.^2;&#xA;y1h=y1.^2+h.^2;&#xA;terrc=x2.*(log( (y2+fac22)./(y2+fac22h))-...&#xA;    log( (y1+fac21)./(y1+fac21h))) -...&#xA;    x1.*( log( (y2+fac12)./(y2+fac12h))-log( (y1+fac11)./(y1+fac11h))) +...&#xA;    y2.*(log( (x2+fac22)./(x2+fac22h))-log( (x1+fac12)./(x1+fac12h))) -...&#xA;    y1.*(log( (x2+fac21)./(x2+fac21h))-log( (x1+fac11)./(x1+fac11h))) +...&#xA;    h.*(asin( (y2h +y2.*fac22h)./( (y2+fac22h).*fac2h))-...&#xA;    asin( (y2h +y2.*fac12h)./( (y2+fac12h).*fac2h))-...&#xA;    asin( (y1h +y1.*fac21h)./( (y1+fac21h).*fac1h))+...&#xA;    asin( (y1h +y1.*fac11h)./( (y1+fac11h).*fac1h)));&#xA;terrc=sum(G.*rho.*terrc);&#xA;end&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The licence is as follows:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Copyright (c) 2016, Jack&#xA;All rights reserved.&#xA;&#xA;Redistribution and use in source and binary forms, with or without&#xA;modification, are permitted provided that the following conditions are&#xA;met:&#xA;&#xA;    * Redistributions of source code must retain the above copyright&#xA;      notice, this list of conditions and the following disclaimer.&#xA;    * Redistributions in binary form must reproduce the above copyright&#xA;      notice, this list of conditions and the following disclaimer in&#xA;      the documentation and/or other materials provided with the distribution&#xA;&#xA;THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS &quot;AS IS&quot;&#xA;AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE&#xA;IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE&#xA;ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE&#xA;LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR&#xA;CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF&#xA;SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS&#xA;INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN&#xA;CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)&#xA;ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE&#xA;POSSIBILITY OF SUCH DAMAGE.&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="6044" LastEditorUserId="94" LastEditDate="2017-01-12T10:32:14.963" LastActivityDate="2017-01-12T10:32:14.963" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8069" PostTypeId="2" ParentId="8067" CreationDate="2016-05-26T15:13:43.043" Score="17" Body="&lt;p&gt;To understand why the nesting ratio of 3 is preferred to the nesting ratio of 2, it is important to understand the following two features of WRF:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Grids are Arakawa C-staggered: mass points are at cell centers,&#xA; u-velocities are at east-west cell edges, v-velocities are at&#xA; north-south cell edges. See &lt;a href=&quot;http://people.atmos.ucla.edu/brianpm/download/mesinger_arakawa_1976.pdf&quot;&gt;Mesinger and Arakawa 1976&lt;/a&gt;, Chapter 4&#xA; for a good description and explanation of Arakawa staggering. WRF's&#xA; grid in computer memory looks like this:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;   +-------+-------+-------+&#xA;   |     v |     v |     v |&#xA;j=3|       |       |       |&#xA;   | u   p | u   p | u   p |&#xA;   +-------+-------+-------+&#xA;   |     v |     v |     v |&#xA;j=2|       |       |       |&#xA;   | u   p | u   p | u   p |&#xA;   +-------+-------+-------+&#xA;   |     v |     v |     v |&#xA;j=1|       |       |       |&#xA;   | u   p | u   p | u   p |&#xA;   +-------+-------+-------+&#xA;      i=1     i=2     i=3&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Thus, &lt;code&gt;p(1,1)&lt;/code&gt; is geographically located $\Delta x /2$ East of &lt;code&gt;u(1,1)&lt;/code&gt; and  $\Delta x /2$ south of &lt;code&gt;v(1,1)&lt;/code&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) For computational efficiency and accuracy, the data from the child (nested) domain is copied to the parent domain. This is opposite from the data going from parent to child, which is interpolated. For more specifics, see the WRF Registry documentation by &lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/WG2/software_2.0/registry_schaffer.pdf&quot;&gt;Michalakes and Schaffer&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a consequence of the above two, it is more computationally efficient and accurate to use a nesting ratio of 3, rather than 2. In the example below, for 2:1 nesting ratio and 1-d case for simplicity, &lt;code&gt;u&lt;/code&gt; values are simply copied from child to parent array because these points are guaranteed to overlap between two grids. Notice that the &lt;code&gt;p&lt;/code&gt; points do not overlap and child &lt;code&gt;p&lt;/code&gt; values must be interpolated to the parent. This induces computational overhead and numerical damping of the $2\Delta x$ wavelength in mass:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;child  u   p   u   p   u   p   u&#xA;       +-------+-------+-------+&#xA;       |    \     /    |&#xA;       |     \   /     |&#xA;       |      \ /      |&#xA;       v       v       v&#xA;&#xA;parent U       P       U&#xA;       +---------------+&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;In a 3:1 nesting ratio however, both the velocity and mass points overlap, and a simple copy is feasible:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;child  u   p   u   p   u   p   u&#xA;       +-------+-------+-------+&#xA;       |           |           |&#xA;       |           |           |&#xA;       v           v           v&#xA;&#xA;parent U           P           U&#xA;       +-----------------------+&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="192" LastActivityDate="2016-05-26T15:13:43.043" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8071" PostTypeId="1" CreationDate="2016-05-27T02:20:11.870" Score="2" ViewCount="107" Body="&lt;p&gt;What are the numerical methods used for solving shallow water equations (PDEs) with a mass source, at the synoptic scales of the atmosphere, if I have a finite east-west boundary (may be periodic wave solutions)? What are the limitations of the methods?&lt;/p&gt;&#xA;" OwnerUserId="5378" LastActivityDate="2016-05-27T02:20:11.870" Title="Numerical methods for solving shallow-water equations with a source" Tags="|atmosphere-modelling|numerical-modelling|synoptic|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8073" PostTypeId="1" AcceptedAnswerId="8074" CreationDate="2016-05-27T14:05:58.933" Score="6" ViewCount="1015" Body="&lt;p&gt;In &lt;a href=&quot;http://www.soest.hawaii.edu/PubServices/MullerNear-BoundaryProcP102-106.pdf&quot;&gt;this&lt;/a&gt; paper by Muller and Garrett it is stated:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It is a standard expectation that&#xA;  currents in the ocean interior with frequencies&#xA;  much less than the Coriolis&#xA;  frequency will lead to an Ekman flux in&#xA;  the frictionally influenced boundary&#xA;  layer near a solid boundary, and that convergence or&#xA;  divergence of this flux will have a back effect on the&#xA;  interior currents.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I do not quite understand what is the frequency of a current.&#xA;How does it dynamically relate to the Coriolis frequency?&lt;/p&gt;&#xA;" OwnerUserId="6001" LastActivityDate="2016-05-30T03:43:15.840" Title="ocean current frequency" Tags="|oceanography|ocean-currents|coriolis|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8074" PostTypeId="2" ParentId="8073" CreationDate="2016-05-27T15:40:01.350" Score="6" Body="&lt;p&gt;Ocean currents can be described as flow oscillations that are forced at different frequencies. In the absence of any external forces (wind, friction), the resulting flow is the &lt;a href=&quot;http://marine.rutgers.edu/dmcs/ms501/2004/NotesWilkin/#_Toc89497136&quot; rel=&quot;nofollow noreferrer&quot;&gt;inertial motion&lt;/a&gt;, which is the response to the balance between Coriolis and inertia. The Coriolis parameter, $f$, can be described as a frequency: the effective planetary rotation frequency of a parcel of water. So, $f$ is called Coriolis frequency or inertial frequency. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are many examples of currents that do not oscillate at the inertial frequency. The simplest examples are the tides. For instance, at 43.5N, the Coriolis frequency is $10^{-4}$ $s^{-1}$, which is equivalent to &lt;a href=&quot;http://www.physocean.icm.csic.es/Utilities/calculators/coriolis-en.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;an inertial period of $17.4 h$&lt;/a&gt;. The main semi-diurnal tidal constituent, $M_2$, has a period of $12.42 h$, which results in a frequency larger than the inertial frequency (at mid-latitudes). The oscillations that happen at frequencies larger than Coriolis are called super-inertial flows. On the other hand, the diurnal tides (e.g., $K_1$, $O_1$) have periods of around $24h$ and thus have frequencies smaller than the inertial frequency (at mid-latitudes). The oscillations that happen at frequencies smaller than Coriolis are called sub-inertial flows.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/j34Tq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/j34Tq.png&quot; alt=&quot;http://www.boya-agl.st.ieo.es&quot;&gt;&lt;/a&gt;Flow spectrum showing energy peaks at certain frequencies: diurnal tides ($O_1, K_1$), semidiurnal tide ($M_2$), and Coriolis (inertial) frequency ($f$). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the real ocean, the balance between planetary vorticity (Coriolis) and inertia is only part of the story. There are usually other forces acting on the flow. For instance, when the balance is between Coriolis and the pressure gradient, we end up with the &lt;a href=&quot;https://en.wikipedia.org/wiki/Geostrophic_current&quot; rel=&quot;nofollow noreferrer&quot;&gt;geostrophic balance&lt;/a&gt;. The resulting geostrophic currents can be described as a &lt;a href=&quot;https://en.wikipedia.org/wiki/Geostrophic_current#Rotating_waves_of_zero_frequency&quot; rel=&quot;nofollow noreferrer&quot;&gt;zero-frequency motion&lt;/a&gt; as there is no acceleration (steady-state). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another important force is the effect of the wind. When we consider the balance between Coriolis (planetary rotation) and the frictional force (stress) caused by the wind, the balance results in &lt;a href=&quot;https://en.wikipedia.org/wiki/Ekman_transport&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ekman flow&lt;/a&gt;. In the Ekman case, the mixing in the layer near the surface (boundary layer) needs to be considered. The same type of balance is present in the ocean in the vicinity of the bottom, as another boundary layer is established there for the flow to go to zero at the bottom. The resulting effect of these frictional forces is that the flow does no longer oscillate at inertial frequencies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the paper you mention, they describe how the frictional effects near the boundary (Ekman balance) influence the interior flow. The interior of the ocean tends to be in geostrophic balance (frequencies smaller than inertial). The boundary flow effects tend to propagate into the interior modifying the geostrophic balance. A good example of this effect is Ekman pumping: cyclonic winds cause &lt;a href=&quot;https://en.wikipedia.org/wiki/Ekman_transport&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ekman transport&lt;/a&gt;, that in turn causes a surface divergence, and in order to balance the flow, result in vertical flow (upwelling). This effect is called Ekman pumping and modifies the interior flow to compensate boundary flows.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="200" LastEditDate="2016-05-30T03:43:15.840" LastActivityDate="2016-05-30T03:43:15.840" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8075" PostTypeId="2" ParentId="7027" CreationDate="2016-05-27T17:02:19.317" Score="0" Body="&lt;p&gt;The US National Park Service refers to a forested area directly below tree line as &quot;subalpine forest.&quot; (&lt;a href=&quot;https://www.nps.gov/olym/learn/nature/subalpine-forests.htm&quot; rel=&quot;nofollow&quot;&gt;NPS - Subalpine Forest)&lt;/a&gt;.  &lt;/p&gt;&#xA;" OwnerUserId="4509" LastActivityDate="2016-05-27T17:02:19.317" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8077" PostTypeId="1" AcceptedAnswerId="8079" CreationDate="2016-05-29T00:42:50.380" Score="-1" ViewCount="368" Body="&lt;p&gt;I was looking at the temperature plots in Nashik, India and noticed an intriguing trend.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/T6WWr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/T6WWr.jpg&quot; alt=&quot;screenshot from WeatherUnderground forecast&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What could explain this trend? [screenshot from WeatherUnderground forecast] Shouldn't the plot be smoother? Other cities have significantly smoother plots.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To confirm that this was not an error in the app, result from Google Weather was tallied and matched.&lt;/p&gt;&#xA;" OwnerUserId="6054" LastEditorUserId="6054" LastEditDate="2016-05-29T00:48:37.217" LastActivityDate="2016-05-29T05:08:45.553" Title="Temperature Fluctuation in a Day" Tags="|weather-forecasting|" AnswerCount="1" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8078" PostTypeId="1" CreationDate="2016-05-29T03:21:10.660" Score="0" ViewCount="916" Body="&lt;p&gt;What sort of geological features would you look for to find this precious resource? &lt;/p&gt;&#xA;" OwnerUserId="6055" LastActivityDate="2016-05-31T12:19:07.853" Title="What sort of geological features would you look for to find copper?" Tags="|geology|earth-observation|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8079" PostTypeId="2" ParentId="8077" CreationDate="2016-05-29T05:08:45.553" Score="0" Body="&lt;p&gt;Many possible mechanisms can create temperature fluctuations on the scale of an hour or two. First there is the met site itself. Are there trees or  buildings that could provide partial shade, especially when the sun is low in the sky? Are there buildings that could reflect sunlight directly onto the instrumentation? &#xA;Then there are local anomalies. Are there gully winds? Do cloud banks form in the mornings, or high cumulus towers build up in the afternoons (quite common in the Western Ghats of India)? Is there a local temperature inversion, and does it disperse daily? What kind of local wind patterns are there? Is there a lake nearby that could create local cooling if the winds are in the right direction? Conversely, is there a source of local heat anomalies - factories, power stations?&#xA;On the larger scale, what is the area topography, and what local air circulation does it create? Is there some interaction between monsoonal air flow and continental air masses? What turbulence does this create?&#xA;Some bizarre anomalies are also possible, like birds roosting on the instrumentation!&#xA;Really, there is no short-cut answer. The only solution is to go there with an unbiased and inquiring mind, and check out what's going on. I'm guessing that for such a consistent fluctuation it will be something obvious. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-05-29T05:08:45.553" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8080" PostTypeId="2" ParentId="8078" CreationDate="2016-05-29T05:26:45.067" Score="4" Body="&lt;p&gt;Two types, low volume high concentrations, and vice versa. For high concentrations start with gravity mapping, and check out high Bouguer anomalies. Generally speaking basic and intermediate igneous, and metamorphic terraines are a better bet than sedimentary terrains - though circulating groundwaters and water-rock interaction can produce local copper shows almost anywhere. Regional mapping of surface water and sediment chemistry should highlight the areas worth exploring. Search for oxidized copper minerals like malachite, azurite, brochantite, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Australia one of the richest copper mining areas was famously discovered by a dog chasing a rabbit into its' hole. The dog owner found malachite in the excavated spoil of the rabbit warren.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the big industrial scale, (high volume, low grade) look for copper porphyry of Andean type, which should be obvious from general geological mapping.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A crude but novel way of exploring is to dump bits of scrap iron in local streams, then check them out a few weeks/months later to see if iron-copper exchange has occurred.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-05-29T05:26:45.067" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8081" PostTypeId="2" ParentId="8078" CreationDate="2016-05-29T13:03:33.383" Score="0" Body="&lt;p&gt;A few ways:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Accidentally, as Gorden Stranger and his Australian example.&lt;br&gt;&#xA;2) River sediments, sometimes companies will go down a river checking for trace amounts of copper, if there is a change along the way then you know there is copper nearby.&lt;br&gt;&#xA;3) Where there are no mines, it's highly likely there's going to be a lot of copper in area's where there has never been mines, for example in the middle of a desert.&lt;br&gt;&#xA;4) Large quarries&lt;br&gt;&#xA;5) How does copper form, if you can work this out then you can map areas where it might be likely that copper would form and you can drill around a bit&lt;br&gt;&#xA;6) Landfalls, often you'll be able to see pieces of copper after large landfalls or when bits of cliff break off.&lt;/p&gt;&#xA;" OwnerUserId="5977" LastActivityDate="2016-05-29T13:03:33.383" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8082" PostTypeId="2" ParentId="7556" CreationDate="2016-05-29T16:57:27.150" Score="3" Body="&lt;p&gt;These are classed as ice spikes. You are correct in noting the occurrence downstream of waterfalls, as this extra turbulence is part of the formation process. The &lt;a href=&quot;http://nd.water.usgs.gov/sw/iceformations.html&quot; rel=&quot;nofollow&quot;&gt;USGS page here&lt;/a&gt; has information on the formations, photographs and a list of criteria involved in their formation:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The winter conditions at each of the ice formation’s locations were&#xA;  similar:&lt;/p&gt;&#xA;  &#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;Freezing or sub-zero temperatures and low flow in channel during    winter months&lt;/li&gt;&#xA;  &lt;li&gt;Ice covered the surface of the stream and accumulated at depths long    the banks restricting flow&lt;/li&gt;&#xA;  &lt;li&gt;In each instance, water flowed over a structure such as a weir or    beaver dam causing turbulence in the flow&lt;/li&gt;&#xA;  &lt;li&gt;Due to the turbulence and restriction in flow, water emerged from    small surface openings downstream of the structure and began to&lt;br&gt;&#xA;  freeze – probably rapidly in some cases due to the sub-zero&lt;br&gt;&#xA;  temperatures at times&lt;/li&gt;&#xA;  &lt;li&gt;Whether the freezing water resulted in a “columnar” or a “frothy,    bubble” ice structure depended on the unique conditions at each&lt;br&gt;&#xA;  location and the weather conditions over time&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6057" LastActivityDate="2016-05-29T16:57:27.150" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8085" PostTypeId="2" ParentId="7986" CreationDate="2016-05-29T23:14:32.670" Score="6" Body="&lt;p&gt;The link is the conservation of mass equation: $$ \frac{\partial u}{\partial x} + \frac{\partial v}{\partial y} + \frac{\partial w}{\partial z} = 0. $$&#xA;Briefly, Ekman pumping is the horizontal divergence of the Ekman transport. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we integrate this expression over the Ekman layer,&#xA;$$ \int_{-D}^0 \frac{\partial u}{\partial x} dz + \int_{-D}^0 \frac{\partial v}{\partial y} dz + \int_{-D}^0 \frac{\partial w}{\partial z} dz = 0$$ &#xA;where $D$ is the height of the Ekman layer we take $z=0$ to be the surface.  This gives&#xA;$$ \frac{\partial}{\partial x} \int_{-D}^0  u dz +  \frac{\partial }{\partial y} \int_{-D}^0 v dz + w_{z=0} - w_{z=-D} = 0$$ or,&#xA;$$ \frac{\partial}{\partial x} U +  \frac{\partial }{\partial y} V + w_{z=0} - w_{z=-D} = 0$$ &#xA;where $U$ and $V$ are the horizontal volume (Ekman) transports.  As a boundary condition we take $w_{z=0} = 0$ leaving&#xA;$$ w_{z=-D} = \frac{\partial}{\partial x} U +  \frac{\partial }{\partial y} V. $$&#xA;So, the Ekman pumping velocity is the horizontal divergence of the Ekman transport (and thus also proportional to the curl of the wind stress).&lt;/p&gt;&#xA;" OwnerUserId="6059" LastActivityDate="2016-05-29T23:14:32.670" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8086" PostTypeId="1" AcceptedAnswerId="8087" CreationDate="2016-05-30T10:46:04.820" Score="4" ViewCount="5468" Body="&lt;p&gt;I want to regrid GCM data available on Gaussian grids to regular grids, say at 1 deg X 1 deg.&#xA;How to do this using &lt;code&gt;CDO&lt;/code&gt; or &lt;code&gt;Python&lt;/code&gt; or &lt;code&gt;MATLAB&lt;/code&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit 1:&lt;/strong&gt; Data format is &lt;code&gt;netcdf&lt;/code&gt;.&lt;/p&gt;&#xA;" OwnerUserId="5330" LastEditorUserId="5330" LastEditDate="2016-05-31T06:32:35.303" LastActivityDate="2018-09-02T00:43:34.113" Title="Interpolate Gaussian grids to regular fixed grids using bilinear interpolation?" Tags="|meteorology|atmosphere-modelling|weather-forecasting|climate-models|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8087" PostTypeId="2" ParentId="8086" CreationDate="2016-05-30T13:40:32.007" Score="9" Body="&lt;h1&gt;climate data operators (CDO)&lt;/h1&gt;&#xA;&#xA;&lt;h2&gt;define grid&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;We define a lat-lon target grid with 1°x1° grid cell size 30x30 grid cells starting at 40°N and -10°E (=10°W):&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;gridtype = lonlat &#xA;xsize    =  30 &#xA;ysize    =  30 &#xA;xfirst   = -10 &#xA;xinc     =   1 &#xA;yfirst   =  40 &#xA;yinc     =   1&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;This text is written into a text file. See &lt;a href=&quot;https://code.zmaw.de/projects/cdo/embedded/index.html#x1-150001.3.2&quot;&gt;section 1.3.2 CDO Manual&lt;/a&gt; for details and further examples.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you already have a netCDF file which has data on your target grid, you can also extract the grid definition from that file:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cdo griddes FILE_WITH_TARGET_GRID.nc &amp;gt; myGridDef&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;code&gt;myGridDef&lt;/code&gt; is a text file.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;interpolate data&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;I assume that we do a bilinear interpolation. This is done with the &lt;code&gt;remapbil&lt;/code&gt; operator via:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cdo remapbil,myGridDef INPUT_FILE.nc OUTPUT_FILE.nc&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The grid of your input data needs to be properly defined in your input file (that is often a problem).&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;'properly defined' grid&lt;/h2&gt;&#xA;&#xA;&lt;h3&gt;Alternative 1&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;The spatial dimensions of the data variable (SST in the example below) need to be named &lt;code&gt;lon&lt;/code&gt; and &lt;code&gt;lat&lt;/code&gt;. Additionally, coordinate variables &lt;code&gt;lon&lt;/code&gt; and &lt;code&gt;lat&lt;/code&gt; have to exist (time independent!). These need to have correct coordinate variable attributes (see example below).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Example:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;dimensions:&#xA;    lon = 30 ;&#xA;    lat = 30 ;&#xA;    time = UNLIMITED ; // (24 currently)&#xA;variables:&#xA;    double lon(lon) ;&#xA;            lon:standard_name = &quot;longitude&quot; ;&#xA;            lon:long_name = &quot;longitude&quot; ;&#xA;            lon:units = &quot;degrees_east&quot; ;&#xA;            lon:axis = &quot;X&quot; ;&#xA;    double lat(lat) ;&#xA;            lat:standard_name = &quot;latitude&quot; ;&#xA;            lat:long_name = &quot;latitude&quot; ;&#xA;            lat:units = &quot;degrees_north&quot; ;&#xA;            lat:axis = &quot;Y&quot; ;&#xA;    double time(time) ;&#xA;            time:standard_name = &quot;time&quot; ;&#xA;            time:long_name = &quot;time&quot; ;&#xA;            time:units = &quot;seconds since 1900-01-01 00:00:00&quot; ;&#xA;            time:calendar = &quot;standard&quot; ;&#xA;            time:axis = &quot;T&quot; ;&#xA;    float SST(time, lat, lon) ;&#xA;            SST:long_name = &quot;sea_surface_temperature&quot; ;&#xA;            SST:units = &quot;degree celsius&quot; ;&#xA;            SST:_FillValue = NaNf ;&#xA;            SST:missing_value = NaNf ;&#xA;            SST:var_desc = &quot;sea surface temperature&quot; ;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;h3&gt;Alternative 2&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;The spatial dimensions and corresponding variables exist in the source file but are not denoted as &lt;code&gt;lon&lt;/code&gt; and &lt;code&gt;lat&lt;/code&gt;. Then each data variable (SST, in this example) needs to have an attribute &lt;code&gt;coordinates&lt;/code&gt; that holds the names of the coordinate variables.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;SST:coordinates = &quot;lon lat&quot; ;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Example:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;dimensions:&#xA;    TSTEP = UNLIMITED ; // (24 currently)&#xA;    COL = 112 ;&#xA;    ROW = 106 ;&#xA;variables:                     &quot; ;&#xA;    double lon(ROW, COL) ;&#xA;        lon:standard_name = &quot;longitude&quot; ;&#xA;        lon:long_name = &quot;longitude coordinate&quot; ;&#xA;        lon:units = &quot;degrees_east&quot; ;&#xA;        lon:_CoordinateAxisType = &quot;Lon&quot; ;&#xA;    double lat(ROW, COL) ;&#xA;        lat:standard_name = &quot;latitude&quot; ;&#xA;        lat:long_name = &quot;latitude coordinate&quot; ;&#xA;        lat:units = &quot;degrees_north&quot; ;&#xA;        lat:_CoordinateAxisType = &quot;Lat&quot; ;&#xA;    double time(TSTEP) ;&#xA;        time:standard_name = &quot;time&quot; ;&#xA;        time:long_name = &quot;time&quot; ;&#xA;        time:units = &quot;seconds since 1900-01-01 00:00:00&quot; ;&#xA;        time:calendar = &quot;standard&quot; ;&#xA;    float SST(TSTEP, ROW, COL) ;&#xA;        SST:long_name = &quot;sea_surface_temperature&quot; ;&#xA;        SST:units = &quot;degree celsius&quot; ;&#xA;        SST:coordinates = &quot;lon lat&quot; ;&#xA;        SST:var_desc = &quot;sea surface temperature&quot; ;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;h3&gt;Note:&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;If the coordinate variables are missing, then they can be created via the &lt;code&gt;setgrid&lt;/code&gt; operator. If we want to add a grid definition to the source file then we need the source file's grid definition in the text file (see 'define grid').&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cdo setgrid,mySourceGridDef INFILE_NO_COORDS.nc INFILE_WI_COORDS.nc&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="5594" LastEditorUserId="5594" LastEditDate="2016-05-30T15:50:17.233" LastActivityDate="2016-05-30T15:50:17.233" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8088" PostTypeId="2" ParentId="8078" CreationDate="2016-05-31T12:19:07.853" Score="2" Body="&lt;p&gt;Copper can be found in exploitable concentrations in a variety of environments, most significantly as Hydrothermal (hot fluid) deposits.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order of significance, here are the main types of copper deposits:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Porphyry deposits - account for 50-60% of current world production.&lt;/li&gt;&#xA;&lt;li&gt;Sediment-hosted deposits&lt;/li&gt;&#xA;&lt;li&gt;Red-bed deposits&lt;/li&gt;&#xA;&lt;li&gt;Volcanogenic massive sulphide deposits (VMS)&lt;/li&gt;&#xA;&lt;li&gt;Magmatic sulphide deposits&lt;/li&gt;&#xA;&lt;li&gt;Sedimentary exhalative (SEDEX)&lt;/li&gt;&#xA;&lt;li&gt;Epithermal&lt;/li&gt;&#xA;&lt;li&gt;Copper skarns&lt;/li&gt;&#xA;&lt;li&gt;Vein-style deposits&lt;/li&gt;&#xA;&lt;li&gt;Supergene&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;So in terms of geological features, I would look anywhere where there has been a large amount of intrusive rock and hydrothermal fluid interaction, and focus on Porphyry deposits. These would show as anomalies in geophysical surveys. On a smaller scale, it really depends on the local geology - there is a certain concentration of copper all over the Earth's crust, but concentrations of copper may not always show as obvious features on the surface...&lt;/p&gt;&#xA;" OwnerUserId="5209" LastActivityDate="2016-05-31T12:19:07.853" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8089" PostTypeId="1" CreationDate="2016-05-31T13:34:29.613" Score="4" ViewCount="50" Body="&lt;p&gt;I have collected data (spectral bands) from Landsat 4-5 and Landsat 8. I was calculating NDVI when I noticed that the two Landsats have different band numbers designated as Red and Near Infra Red (needed for NDVI calculation). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I checked the wavelengths associated with these bands at &lt;a href=&quot;http://landsat.usgs.gov/band_designations_landsat_satellites.php&quot; rel=&quot;nofollow&quot;&gt;Landsat Band Description&lt;/a&gt; I noticed that the wavelengths also differ a bit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example: I used bands 3 and 4 (Red &amp;amp; Near Infra Red) from Landsat 4-5 and bands 4 and 5 (Red and Near Infra Red) from Landsat 8 for NDVI calculation, but the wavelength range of band 3 in Landsat 4-5 is not exactly the same as of band 4 in Landsat 8. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any way to convert things so that they are same and comparable. I got big variances between NDVI values from the two satellites and have the idea that's because the wavelengths differ.&lt;/p&gt;&#xA;" OwnerUserId="6066" LastEditorUserId="192" LastEditDate="2016-06-01T00:01:06.440" LastActivityDate="2016-06-01T00:01:06.440" Title="Conversion factor between different Landsats?" Tags="|measurements|remote-sensing|satellites|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8090" PostTypeId="1" AcceptedAnswerId="8099" CreationDate="2016-05-31T14:20:09.250" Score="4" ViewCount="1542" Body="&lt;p&gt;Is there a package for R to plot Schmidt nets, like it is done in geology?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far, I only know software like Stereonet. However I think it would make a lot of sense to handle these data in R, to have so much more possibilities in calculations and statistics.&lt;/p&gt;&#xA;" OwnerUserId="4784" LastEditorUserId="595" LastEditDate="2016-07-25T10:24:04.307" LastActivityDate="2016-07-25T10:24:04.307" Title="Plotting stereonets in R" Tags="|geology|structural-geology|data-analysis|software|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8091" PostTypeId="1" CreationDate="2016-06-01T01:22:35.790" Score="7" ViewCount="666" Body="&lt;p&gt;About a month ago, &lt;a href=&quot;http://www.nws.noaa.gov/os/notification/tin16-11gfs_gdasaaa.htm&quot;&gt;the GFS was upgraded&lt;/a&gt;. Among other things (like making parallel GFS data available), the upgrade notice said:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;Include hourly forecasts out to 120 hr&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Now, this seemed strange to me. The NAM (which goes out to only 84 hours) outputs forecasts every 3 hours. Indeed, with the exception of very short-range models like the RAP, HRRR, and SREF (WRF), no models output data hourly. Since the NAM is intended fine-tuning shorter-range forecasts, and the GFS for longer-range patterns, why did the NWS upgrade the GFS to hourly output out to hour 120?&lt;/p&gt;&#xA;" OwnerUserId="20" LastActivityDate="2016-06-01T01:22:35.790" Title="Why did the GFS switch to hourly forecasts through hour 120?" Tags="|models|weather-forecasting|gfs|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8094" PostTypeId="1" AcceptedAnswerId="8102" CreationDate="2016-06-01T16:03:18.970" Score="3" ViewCount="6274" Body="&lt;p&gt;I live in New York and I am investing in a carbon offset program in Korea to decommission a coal electricity generation plant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Will I ever breathe the cleaner air as a result of that project? And how long with that air to get here (and back around)?&lt;/p&gt;&#xA;" OwnerUserId="6075" LastActivityDate="2017-12-02T00:19:25.923" Title="How long does it take air to circle the world?" Tags="|atmosphere|air-currents|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8095" PostTypeId="2" ParentId="7831" CreationDate="2016-06-01T19:04:51.990" Score="5" Body="&lt;p&gt;The easiest thing to do to make your copper pole safe would be to ground it and disconnect the lights from your house wiring when they aren't in use (if they are plug-in lights and not solar). This article on &lt;a href=&quot;http://science.howstuffworks.com/nature/natural-disasters/lightning7.htm&quot; rel=&quot;noreferrer&quot;&gt;how lightning rods work&lt;/a&gt; is a pretty good explanation of why you do want to ground a tall, conductive pole. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Electricity will travel the path of least resistance to ground. That's why folks working on electric lines have insulating shoes and gloves, but folks working on equipment sensitive to static electricity wear grounding straps. When you're working with high current or potential, you don't want to be the shortest path to ground. When you don't want the sensitive equipment you're working on to be the shortest path to ground, you attach a strap to yourself to provide a better path to ground for any static charge that might accidentally build up. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When lightning strikes, the energy will take the path of least resistance, and has so much power that it can jump small air gaps. If the gap is small enough, and close enough to a good conductor, it becomes the shortest path to ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A copper pole is definitely a good candidate for lightning to use as a path to ground, so what you want to make sure of is that the lighting travels completely down the rod to ground, and doesn't jump to, say, the wires of your lights (through their insulation) and travel into your house wiring, frying electronics and generally wreaking havoc. The best way to do that is to ground it properly and make it a sort of lightning rod. It won't &quot;attract&quot; lightning strikes, but if one does occur, it is safer to let it follow the pipe to ground than maybe hit your house. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an aside, &lt;a href=&quot;http://thunder.msfc.nasa.gov/primer/primer2.html&quot; rel=&quot;noreferrer&quot;&gt;according to a lightning primer from NASA&lt;/a&gt; although cloud-to-ground lightning is the most dangerous and damaging, it is the least common. &lt;/p&gt;&#xA;" OwnerUserId="6076" LastActivityDate="2016-06-01T19:04:51.990" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8097" PostTypeId="1" AcceptedAnswerId="8098" CreationDate="2016-06-02T00:09:22.057" Score="4" ViewCount="240" Body="&lt;p&gt;I'm aware that andesite consists of about 60 percent silica and as for minerals, pretty sure it's usually pyroxene and plagioclase. What form would these take on if they were to be separated? Especially interesting, I think, is what would happen to the silica: would it be in its &quot;commercial&quot; powdered form?&lt;/p&gt;&#xA;" OwnerUserId="6080" LastEditorUserId="725" LastEditDate="2016-06-02T06:45:58.567" LastActivityDate="2016-06-02T09:27:38.780" Title="Upon breaking apart andesite, what do you get?" Tags="|geology|geochemistry|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8098" PostTypeId="2" ParentId="8097" CreationDate="2016-06-02T06:01:25.400" Score="7" Body="&lt;p&gt;By definition andesite is mainly plagioclase (mostly variety andesine),and pyroxene with either quartz or olivine (not both), and minor amounts of magnetite, ilmenite, zircon, apatite, possibly biotite mica, and maybe a few traces of rarer minerals. The pyroxene is probably a mixture of orthopyroxene and augite. In addition to plagioclase there may be small quantities of other, more alkaline feldspars.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Andesite is &lt;em&gt;chemically&lt;/em&gt; about 60+/-3% silica, SiO2, but the amount of free silica is very small, if present at all - at most 2 or 3 percent. So no, you won't extract commercial powdered silica. Better than 99.9% pure silica is found very abundantly in some quartzites, a common sedimentary rock. So nobody is going to try to extract silica from other silicates.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-02T06:01:25.400" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8099" PostTypeId="2" ParentId="8090" CreationDate="2016-06-02T09:18:32.983" Score="4" Body="&lt;p&gt;You might try the &lt;a href=&quot;https://cran.r-project.org/web/packages/RockFab/&quot; rel=&quot;nofollow&quot;&gt;RockFab package&lt;/a&gt;. I am not a structural geologist but I use other R packages for geological endevours.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://cran.r-project.org/web/packages/RockFab/RockFab.pdf&quot; rel=&quot;nofollow&quot;&gt;Documentation&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6083" LastEditorUserId="595" LastEditDate="2016-06-02T11:17:53.833" LastActivityDate="2016-06-02T11:17:53.833" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8100" PostTypeId="2" ParentId="8097" CreationDate="2016-06-02T09:27:38.780" Score="4" Body="&lt;p&gt;I'll add a bit to Gordon's answer. Andesite usually contains several large crystals (that can be pyroxene, plagioclase, olivine, or any combination of these). Their sizes can be up to several mm. These crystals will be set in a groundmass (also called matrix) of either very fine crystals of all of the other minerals Gordon mentioned, volcanic glass, or both.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you break it mechanically, it will tend to break along mineral grains. Depending on the final size you break the grains to, you might end up with individual grains of each mineral. There is a good chance that some of the groundmass will stick to the larger grains, or that there will be inclusions of other minerals inside the larger minerals. The finer you break it down, the higher chances that each individual grain will be only one mineral (or glass). If required, there are then methods to separate the minerals to have an almost pure fractions of each mineral. For example, magnetic separation will separate oxides from silicates, and it will separate iron-bearing silicates from iron-absent silicates. This is a very time consuming process. Heavy liquids is another methods for separating the minerals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As Gordon said, the rock is around 60% SiO&lt;sub&gt;2&lt;/sub&gt;, but this this is not in the form of quartz (the mineral with the formula SiO&lt;sub&gt;2&lt;/sub&gt;), but rather bound in silicates, such as plagioclase (CaAl&lt;sub&gt;2&lt;/sub&gt;Si&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;8&lt;/sub&gt;) or clinopyroxene (CaMgSi&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;6&lt;/sub&gt;). Separating the chemical SiO&lt;sub&gt;2&lt;/sub&gt; from these minerals to produce commercial grade SiO&lt;sub&gt;2&lt;/sub&gt; is very hard, expensive, and pointless. It is much easier to get SiO&lt;sub&gt;2&lt;/sub&gt; from sandstones, beach sand, and quartzites, most of them are almost pure SiO&lt;sub&gt;2&lt;/sub&gt; in the form of quartz. This is the case because the chemical grade SiO&lt;sub&gt;2&lt;/sub&gt; we use in our own lab has small but higher than expected amounts of ZrO&lt;sub&gt;2&lt;/sub&gt; in it. This basically means that it has a tiny bit of zircon (ZrSiO&lt;sub&gt;4&lt;/sub&gt;) in it. This is a mineral that's extremely resistant to chemical attack, and it accumulates in sedimentary detrital rocks, for example sandstone. Gives you an idea on where the SiO&lt;sub&gt;2&lt;/sub&gt; used to make it came from...&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-06-02T09:27:38.780" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8102" PostTypeId="2" ParentId="8094" CreationDate="2016-06-02T16:32:02.857" Score="1" Body="&lt;p&gt;Quick answer is its too vague to give a firm estimate. The geostrophic wind - what the wind would be in theory with no complicating variables, is a function of height, temperature and latitude. There is a calculator for this on &#xA;&lt;a href=&quot;http://www.shodor.org/os411/courses/_master/tools/calculators/geostrophic/&quot; rel=&quot;nofollow&quot;&gt;http://www.shodor.org/os411/courses/_master/tools/calculators/geostrophic/&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The wind speed for New York could be anything from 1 to about 16 m/sec. If we assume it is 10 m/sec, then the time to circuit the planet would be about 35 days. But then there are massive complicating factors. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-02T16:32:02.857" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8103" PostTypeId="1" AcceptedAnswerId="8107" CreationDate="2016-06-02T18:31:46.823" Score="8" ViewCount="311" Body="&lt;p&gt;I understand that the main issue of global warming is greenhouse gases that trap solar energy instead of allowing it to bounce back into space. That being said, I've always had this impression or idea that the amount of energy released from burning fossil fuels should also have an effect. Consider from antiquity to about 1600 AD, the sum of heat being dumped into the atmosphere came from the sun. Now, after the industrial revolution, a new source has been added, that being human activity (burning coal, burning petrol, burning natural gas, thermonuclear weapons, nuclear reactors). While I suspect human activity has no measurable comparison against the output of the sun, I'm wondering if it has an impact on global warming to any degree.&lt;/p&gt;&#xA;" OwnerUserId="5673" LastActivityDate="2016-06-06T07:13:24.653" Title="Does the amount of energy released from burning of fossil fuels have a measurable impact on global warming?" Tags="|climate-change|fossil-fuel|" AnswerCount="1" CommentCount="12" ClosedDate="2016-06-06T14:10:01.720" ContentLicense="CC BY-SA 3.0" />
  <row Id="8104" PostTypeId="1" CreationDate="2016-06-02T19:30:21.370" Score="4" ViewCount="38" Body="&lt;p&gt;I am trying to find a reputable source that lists how many  acres of wetland are destroyed each year on average in each decade, specifically in the Continental US. I found some secondary sources, but many of them are conflicting, and didn't list primary sources. Are there any primary sources that list the amount of wetland destruction?&lt;/p&gt;&#xA;" OwnerUserId="6086" LastEditorUserId="6086" LastEditDate="2016-06-03T18:45:35.003" LastActivityDate="2016-07-09T01:49:54.310" Title="Where can I find a data set containing wetland loss by decade" Tags="|human-influence|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8105" PostTypeId="1" AcceptedAnswerId="8112" CreationDate="2016-06-03T03:46:58.783" Score="2" ViewCount="1653" Body="&lt;p&gt;In my mind, tornadoes usually appear in flat areas with some wooden houses, but not places like cities with many tall buildings. It is especially rare to see a tornado destroying a series of skyscrapers. Is this true? If so, what is the reason?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="543" LastEditDate="2016-06-03T03:52:09.463" LastActivityDate="2018-12-12T20:51:28.737" Title="Do tornadoes usually avoid areas with many tall buildings?" Tags="|tornado|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8106" PostTypeId="2" ParentId="8105" CreationDate="2016-06-03T04:57:04.737" Score="3" Body="&lt;p&gt;I think you need some statistics to bolster your argument. It could be that there aren't so many big cities in America's 'tornado alloy', so the footprint of a super-cell storm has a low probability of crossing tall buildings. Check out tornado alley on Google Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are still unanswered questions, such as why some supercell's develop tornados, whilst others do not. Also, the question of the mechanism by which  tornados dissipate their energy has not been entirely sorted out. One can say, however, that tornado development requires two conditions: strong thermal convection, and little or no low-level wind shear - such as might occur around large buildings. So the optimum conditions for tornado development are large flat open plains in which warm and cold fronts are converging.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-03T04:57:04.737" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8107" PostTypeId="2" ParentId="8103" CreationDate="2016-06-03T10:21:57.680" Score="5" Body="&lt;p&gt;Yes, it does add to global warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No, it's not currently measurable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Human primary non-renewable energy consumption is about 15TW - and pretty much all of that goes into low-grade heat in the ocean surface and the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Expressed in the same terms as the forcing units of global warming, the forcing effect of that heat is about &lt;a href=&quot;http://dx.doi.org/10.1002/2015GL063514&quot; rel=&quot;nofollow&quot;&gt;1.7%&lt;/a&gt; of the effect of the anthropogenic release of $\ce{CO2}$ to date.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So we can calculate it, but it's not directly measurable as a change to global energy content: it matters, but it's not quantifiable from temperature observations, given current data and techniques.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(Kudos to Pont for the link to the paper)&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="100" LastEditDate="2016-06-06T07:13:24.653" LastActivityDate="2016-06-06T07:13:24.653" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8109" PostTypeId="1" CreationDate="2016-06-03T13:06:40.377" Score="9" ViewCount="1275" Body="&lt;p&gt;&lt;a href=&quot;http://www.ecmwf.int/en/forecasts/documentation-and-support/91-model-levels&quot; rel=&quot;nofollow&quot;&gt;ECMWF Model Levels&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The above link describes the coefficients used to define the ECMWF model levels in pressure in order to compute geopotential height. Is there a similar data for NCEP reanalysis model or is the data already on pressure levels in which case the above step is not required ? To be precise I am looking for the identical data for the T62 NCEP reanalysis data(2.5 x 2.5).&#xA;The NCEP reanalysis model uses the sigma vertical coordinate. The same question can be rephrased in the following manner&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) What are the values of the sigma levels and where can they be downloaded?&#xA;For e.g. if the sigma level is 0.995 and the surface pressure is 1000 hPa then the pressure at the sigma level 0.995 is 995 hPa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Are the sigma levels of the NCEP reanalysis model comparable to the a and b coefficients of the ECMWF model ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The hybrid vertical coordinate of UCAR &lt;a href=&quot;http://www.cesm.ucar.edu/models/atm-cam/docs/usersguide/node25.html&quot; rel=&quot;nofollow&quot;&gt;Community Atmosphere Model(CAM 3.0)&lt;/a&gt; describes a similar equation to that of ECMWF and has explicit coefficients A and B as shown below&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$p(\eta,p_s) = A(\eta)p_0 + B(\eta)p_s$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where p is pressure, $p_s$ is surface pressure, $p_0$ is a specified constant reference pressure and A and B are coefficients that specify the coordinate being used and are defined only at the discrete model levels. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;GOAL&lt;/strong&gt; - I have code that uses ECMWF data as input to run a few calculations. I am looking to run the same code using NCEP renanalysis model data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Page 6 Section 2.2.1 &lt;a href=&quot;http://www.ecmwf.int/sites/default/files/IFS_CY40R1_Part3.pdf&quot; rel=&quot;nofollow&quot;&gt;Vertical Discretization&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Simmons, A.J., Burridge, D.M., An Energy and Angular Momentum Conserving Vertical Coordinate Finite Difference Scheme and Hybrid Vertical Coordinate, Monthly Weather Review 758-766,1981&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Collins, W. D., P. J. Rasch, and Others, Description of the NCAR Community Atmosphere Model (CAM 3.0), Technical Report NCAR/TN-464+STR, National Center for Atmospheric Research, Boulder, Colorado, 210 pp., 2004. &lt;a href=&quot;http://www.cesm.ucar.edu/models/atm-cam/docs/description/description.pdf&quot; rel=&quot;nofollow&quot;&gt;CAM&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2016-06-09T09:19:38.540" LastActivityDate="2016-08-30T08:28:55.393" Title="NCEP reanalysis model levels" Tags="|climate-models|open-data|data-formats|data-analysis|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8112" PostTypeId="2" ParentId="8105" CreationDate="2016-06-03T14:23:45.453" Score="12" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;It is especially rare to see a tornado destroying a series of skyscrapers.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes, it's rare, but not for the reasons you think. The reason that tornados striking downtown areas is rare is that cities are but a tiny fraction of the land area in places where tornados most often occur, and downtown areas are but a tiny fraction of the land area in those cities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, downtown St. Louis, Missouri (the center of tornado alley) has been hit by tornados six times, and downtown Shrevesport, Louisiana (the center of Dixie alley), five times. The &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_tornadoes_striking_downtown_areas_of_large_cities&quot;&gt;list of tornados that have hit the downtown areas of large cities&lt;/a&gt; goes on and on and on. &lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2016-06-03T14:23:45.453" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8113" PostTypeId="1" AcceptedAnswerId="8114" CreationDate="2016-06-04T05:29:05.730" Score="4" ViewCount="1342" Body="&lt;p&gt;It seems to me when reading about minerals, groups and series are spoken about interchangably in similar types of contexts. Is there a difference? If so, what?&lt;/p&gt;&#xA;" OwnerUserId="6080" LastEditorUserId="725" LastEditDate="2016-06-04T10:33:11.657" LastActivityDate="2016-06-04T10:50:58.460" Title="What is the difference between mineral groups and series?" Tags="|geology|geochemistry|mineralogy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8114" PostTypeId="2" ParentId="8113" CreationDate="2016-06-04T10:50:58.460" Score="3" Body="&lt;p&gt;Yes, there is a difference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A mineral &lt;strong&gt;series&lt;/strong&gt; represents mineral which have a well defined solid solution. One of the most known examples is olivine: olivine is not a strictly defined chemical composition for a mineral, but rather a series between the forsterite end-member (Mg&lt;sub&gt;2&lt;/sub&gt;SiO&lt;sub&gt;4&lt;/sub&gt;) and fayalite end-member (Fe&lt;sub&gt;2&lt;/sub&gt;SiO&lt;sub&gt;4&lt;/sub&gt;). Note that if you find a pure end-member in nature, then you have a mineral &lt;strong&gt;species&lt;/strong&gt;. Quite rare for olivine though. There's also the olivine &lt;strong&gt;group&lt;/strong&gt;, which consists of other minerals that do not form a solid solution with the forsterite-fayalite series (for example monticellite CaMgSiO&lt;sub&gt;4&lt;/sub&gt;) or minerals that do form a solid solution, except that it's extremely rare in nature (for example tephroite Mn&lt;sub&gt;2&lt;/sub&gt;SiO&lt;sub&gt;4&lt;/sub&gt;). Here's a comprehensive list of the minerals in the olivine group: &lt;a href=&quot;http://www.mindat.org/min-29264.html&quot; rel=&quot;nofollow&quot;&gt;http://www.mindat.org/min-29264.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another example is the pyroxene &lt;strong&gt;group&lt;/strong&gt;. So for simple Ca-Mg-Fe pyroxenes, you have the clinopyroxene and orthopyroxene &lt;strong&gt;series&lt;/strong&gt;, which consist of the end-members (&lt;strong&gt;species&lt;/strong&gt;, if you find them pure) diopside (CaMgSiO&lt;sub&gt;6&lt;/sub&gt;) - hedenbergite (CaFeSiO&lt;sub&gt;6&lt;/sub&gt;) and enstatite (MgSiO&lt;sub&gt;3&lt;/sub&gt;) - ferrosilite (FeSiO&lt;sub&gt;3&lt;/sub&gt;), respectively. Intermediate clinopyroxenes are also called augite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The distinction is not always clear. For example, the feldspar &lt;strong&gt;group&lt;/strong&gt; traditionally has the plagioclase &lt;strong&gt;series&lt;/strong&gt; (albite-anorthite, NaAlSi&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;8&lt;/sub&gt;-CaAl&lt;sub&gt;2&lt;/sub&gt;Si&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;8&lt;/sub&gt;) and the K-feldspar &lt;strong&gt;species&lt;/strong&gt; (KAlSi&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;8&lt;/sub&gt;, either microcline, orthoclase or sanidine, depending on structure). But in some cases there is a solid solution between albite and K-feldspar, forming the alkali-feldspar &lt;strong&gt;series&lt;/strong&gt;. Nature doesn't always behave according to our rules, and it's important to remember that our classification systems work well with ideal systems but break down often.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://courses.missouristate.edu/emantei/mineralogy/mineral%20classif.html&quot; rel=&quot;nofollow&quot;&gt;Further reading&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-06-04T10:50:58.460" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8115" PostTypeId="1" CreationDate="2016-06-04T20:47:39.543" Score="11" ViewCount="298" Body="&lt;p&gt;I recently went to a beach, and I noticed that the sand seemed to have a few distinct regions.  I'm wondering what would cause this, and how it works.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One region is the part of the beach which is kept wet by the waves, but is far enough away that most waves don't seem to reach all the way to the end of it.  This part consisted of small-grained, &quot;soft&quot; sand.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This region is followed by a region with a lot of small rocks (mostly the size of, say, someone's smallest toe).  This region was located a bit past (i.e.: further into the water) the lowest point the water tended to reach.  This size of the grains of sand of this region blends smoothly into the previous region, so they get progressively larger as you walk further out to the water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The last region is another one of fine-grain sand, and it also had ripples in it (I'm assuming that this is just because of the waves, because I noticed that the waves picked up sand from the peaks of the ripples and pulled it back out to sea).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first two distinct regions seem to be the result of some type of sorting mechanism induced by the wave.  If so, how does this work?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And why was there a second region of fine-grain sand &lt;em&gt;after&lt;/em&gt; the coarse-grain region?&lt;/p&gt;&#xA;" OwnerUserId="4942" LastEditorUserId="725" LastEditDate="2016-06-04T22:34:01.210" LastActivityDate="2019-07-08T15:53:49.250" Title="Waves on sandy beach separating differently-sized rocks?" Tags="|ocean|sedimentology|water|waves|geomorphology|" AnswerCount="2" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="8117" PostTypeId="1" AcceptedAnswerId="8118" CreationDate="2016-06-05T15:51:41.750" Score="3" ViewCount="8743" Body="&lt;p&gt;We have all seen rainbows in our lives. But the other day, I saw a double rainbow! How rare are double rainbows and what causes them to appear?&lt;/p&gt;&#xA;" OwnerUserId="6093" LastActivityDate="2023-10-08T18:54:43.920" Title="How rare are double rainbows?" Tags="|atmosphere|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8118" PostTypeId="2" ParentId="8117" CreationDate="2016-06-05T20:13:19.250" Score="9" Body="&lt;p&gt;A normal single arc rainbow is caused when sunlight enters a raindrop with a light-path refracted&gt;reflected&gt;refracted. A double rainbow occurs when sunlight hits a part of the raindrop at a different angle of incidence, at which the light-path is refracted&gt;reflected&gt;reflected&gt;refracted. Some energy is lost with each reflection, so the double internal reflection emerges as less bright than the primary arc. Also, because there is another internal reflection the colours are inverted. So &lt;em&gt;every&lt;/em&gt; rainbow has a primary and seconday arc. Hence the question becomes: 'Is the observer in a position to see the secondary arc', which  is a matter of geometry between the sun, raindrop and observer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the answer to your question is 'no', it isn't rare at all, in fact a secondary arc is always present somewhere, but is not always visible to the observer for reasons of geometry and background light intensity. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-05T20:13:19.250" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8121" PostTypeId="1" AcceptedAnswerId="8122" CreationDate="2016-06-06T12:11:51.983" Score="1" ViewCount="1645" Body="&lt;p&gt;What I am asking, is exactly the opposite of the yearly rain. It is well measured and it has century long databases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider a given, generally dry area. What I am trying to know: if this area wouldn't be dry, but it would be an open water surface (for example, a sea), but &lt;em&gt;without&lt;/em&gt; any water resupply (i.e. rain), what would be the yearly level loss by evaporation?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think, this information would be useful to calculate the irrigation need of not arable territories because of the lack of rain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additional difficulty: in case of larger areas, this evaporation rate would be probably smaller, because the winds in the central regions get moisture on the borders.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suspect, calculating this would require a relative complex weather simulation, which is not available on the enthusiast level. But maybe some fist rule, estimation or already existing databases can exist.&lt;/p&gt;&#xA;" OwnerUserId="6016" LastEditorUserId="87" LastEditDate="2016-06-07T11:09:15.387" LastActivityDate="2016-06-07T11:09:15.387" Title="How to find/calculate the yearly evaporation of a given area?" Tags="|meteorology|evaporation|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8122" PostTypeId="2" ParentId="8121" CreationDate="2016-06-06T14:28:51.767" Score="6" Body="&lt;p&gt;What you are asking is one of the most difficult issues in hydrology. The evaporation from open water is a function of air temperature, water temperature, humidity, wind speed and fetch, water depth, water salinity,  degree of thermal stratification, and boundary effects (as you correctly point out). It is certainly not a trivial calculation!&#xA;As a first approximation you can apply an empirical coefficient to class-A pan evaporation data, but don't expect any great accuracy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But then you progress towards a further aim of calculating a potential irrigation need. For this purpose I would say that calculating open water evaporation is completely the wrong approach. Rather, calculate the potential evapotranspiration ('ET0'), and then apply appropriate crop factors, as explained in the FAO documentation:&#xA;&lt;a href=&quot;http://www.fao.org/docrep/s2022e/s2022e07.htm&quot;&gt;http://www.fao.org/docrep/s2022e/s2022e07.htm&lt;/a&gt;&lt;br&gt;&#xA;Calculating ET0 is best done using the Penmann-Monteith equation, which is horribly complicated, but there are web sites where you can do the calculations on line. You will need monthly or dekad climate data for the crop(s) you envisage growing. This will be max and min temperature, humidity, average wind speed and average daily hours of bright sunshine. You will also need latitude, longitude and altitude to estimate the solar radiation. Even with all this data, it is a fairly lengthy calculation, but it is your best bet at realistic crop water requirements.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-06T14:28:51.767" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8123" PostTypeId="2" ParentId="8121" CreationDate="2016-06-06T14:31:22.987" Score="3" Body="&lt;p&gt;Depending on the location, evaporation data is collected by some meteorological organisations. &lt;a href=&quot;https://en.wikipedia.org/wiki/Pan_evaporation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Class A pans&lt;/a&gt; or Symon's pans are used to collect daily evaporation data for selected sites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Australia, such data is gridded to produce images like this one, from the &lt;a href=&quot;http://www.bom.gov.au/watl/evaporation/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Australian Bureau of Meteorology&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wizdx.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wizdx.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-06-06T14:31:22.987" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8124" PostTypeId="1" CreationDate="2016-06-06T20:45:56.800" Score="1" ViewCount="36" Body="&lt;p&gt;I have the following data about a region, and would like to compute the visibility for that region, i.e. the distance that a person could see ahead of them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;precipitation (mm/day)&lt;/li&gt;&#xA;&lt;li&gt;dewpoint(degree C)&lt;/li&gt;&#xA;&lt;li&gt;temperature (degree C)&lt;/li&gt;&#xA;&lt;li&gt;relative humidity (%)&lt;/li&gt;&#xA;&lt;li&gt;wind speed (km/h)&lt;/li&gt;&#xA;&lt;li&gt;pressure (kPa)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Does anyone know how I can compute some meaningful visibility measure out of this? This is for a computer model I'm using to model something else entirely, which needs visibility. So I'm stuck having to reconstruct that information from what I have&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd appreciate any help&lt;/p&gt;&#xA;" OwnerUserId="6100" LastActivityDate="2016-06-06T20:45:56.800" Title="How to Compute Visibility" Tags="|meteorology|precipitation|barometric-pressure|" AnswerCount="0" CommentCount="1" ClosedDate="2016-06-07T03:50:27.487" ContentLicense="CC BY-SA 3.0" />
  <row Id="8125" PostTypeId="1" AcceptedAnswerId="8126" CreationDate="2016-06-06T23:07:29.777" Score="1" ViewCount="281" Body="&lt;p&gt;Analysing the constituents of manganese nodules, we find that the relative proportion of minerals differs from that of the surrounding sea water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can someone explain to me why the proportion of the main minerals is so different?&lt;/p&gt;&#xA;" OwnerUserId="6101" LastEditorUserId="595" LastEditDate="2016-06-07T12:44:39.640" LastActivityDate="2016-06-07T12:44:39.640" Title="Why do manganese nodules have different constitution than sea water?" Tags="|oceanography|rocks|mineralogy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8126" PostTypeId="2" ParentId="8125" CreationDate="2016-06-07T05:14:58.487" Score="2" Body="&lt;p&gt;Many reasons: First, the sea water does not have a uniform composition of dissolved metals. Second, if the nodule, either now or in the past, has been in proximity to an oceanic hydrothermal vent ('black smoker') then the source metal concentrations will have been dramatically different. Third, at thermodynamic equilibrium, each metal will have a different liquid-solid phase partition coefficient, and even slow precipitation isn't necessarily at thermodynamic equilibrium. Fourth, the Mn-nodule mineralogy may contain some proportion of clay with different adsorption capacities for different metals. Fifth, These nodules are lying on the sea bed, so it isn't just pure sea water that we are dealing with. There is also slowly circulating pore water from the underlying sediments. This pore water can have a huge range of composition derived from water-rock interaction, depending upon temperature-pressure history, pH/Eh, rock composition, depth of circulation and history of water-rock interaction. Finally, it is more than likely that microbial mediation is involved in metal oxide deposition at the liquid-solid interface (in which case all bets are off in respect of thermodynamic equilibrium), and almost anything can happen, depending upon microbial species, metabolism and micro-ecology.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-07T05:14:58.487" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8129" PostTypeId="1" CreationDate="2016-06-08T05:38:15.943" Score="8" ViewCount="962" Body="&lt;p&gt;Suppose I could drill a hole to mantle at any arbitrary point in the crust, will magma start to rise from the hole and finally become a volcano?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="2470" LastEditDate="2021-08-08T16:57:29.347" LastActivityDate="2021-08-27T06:55:54.347" Title="If I could drill a hole into the mantle, would it form a volcano?" Tags="|volcanology|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="8130" PostTypeId="1" AcceptedAnswerId="8205" CreationDate="2016-06-08T06:51:54.393" Score="9" ViewCount="12710" Body="&lt;p&gt;A low pressure area is associated with rising air while a high pressure area is associated with subsiding air. The best explanation I could come up with is either the cyclone is an exception or the above associations are not an absolute rule in the first place.&#xA;However, none of the articles I read provide an explanation on this phenomenon, indicating that I am missing something trivial.&#xA;Could anyone shed some light on this? I would appreciate a layman explanation. &lt;/p&gt;&#xA;" OwnerUserId="6105" LastEditorUserId="6105" LastEditDate="2016-06-08T11:17:19.507" LastActivityDate="2023-09-06T16:43:07.697" Title="Why does air subside in the Eye - the lowest pressure area of a tropical cyclone?" Tags="|tropical-cyclone|barometric-pressure|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8131" PostTypeId="2" ParentId="8109" CreationDate="2016-06-08T09:33:01.727" Score="5" Body="&lt;h2&gt;Grid Resolution of the NCEP/NCAR reanalysis data&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The data is available on different grids depending on the variables of interest:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The original grid is a T62 &lt;a href=&quot;https://climatedataguide.ucar.edu/climate-model-evaluation/common-spectral-model-grid-resolutions&quot; rel=&quot;nofollow&quot;&gt;Gaussian grid&lt;/a&gt;, which grid cells do not have a constant lon-lat spacing over the whole globe (see e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Gaussian_grid&quot; rel=&quot;nofollow&quot;&gt;Gaussian grid at Wikipedia&lt;/a&gt;), with 28 sigma levels. The sigma levels are listed &lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.spectral.html&quot; rel=&quot;nofollow&quot;&gt;on this page&lt;/a&gt;, where also the surface pressure is available for download. According to the &lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/gridded/faq.html#15&quot; rel=&quot;nofollow&quot;&gt;FAQ&lt;/a&gt;, the sigma coordinate equals &quot;pressure in current level&quot;/&quot;surface pressure&quot;. Thus, the pressure on each sigma level can be obtained via the available data.&lt;/li&gt;&#xA;&lt;li&gt;Secondly, some variables, such as air temperature, are available interpolated onto an equally spaced lon-lat grid of 2.5° x 2.5° resolution with 17 pressure levels. These data are available &lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.pressure.html&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt; including data files with the geopotential height. The pressure levels are listed on the same page.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h2&gt;Comparability with A and B coefficients of ECMWF&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The ECMWF uses the coefficients A and B as well as the reference pressure $p_0$ to describe the levels. NCEP uses just one coefficient ($\sigma$) for this purpose:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\begin{align}&#xA;&amp;amp; \text{ECMWF:} &amp;amp; p\left(\eta,p_s\right) &amp;amp;= A\left(\eta\right) \times p_0 + B\left(\eta\right) \times p_s \\&#xA;&amp;amp; \text{NCEP:} &amp;amp; p\left(\eta,p_s\right) &amp;amp;= \sigma\left(\eta\right) \times p_0 \\&#xA;\end{align}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When we had $p_0 = 0\ \text{bar}$, both representations were the same. In the given situation, there is no unambiguous mapping from a known $\sigma\left(\eta\right)$ to a set of $A\left(\eta\right)$ and $B\left(\eta\right)$. At least if there are no further limiting conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Normally, I do not deal with vertical coordinate systems. Therefore, I am not sure how data on different vertical layers is compared with each other (except of the obvious: interpolating the one data set onto the vertical coordinates of the other data set).&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Summary&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;1) Yes, &lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.spectral.html&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.pressure.html&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The variables Air Temperature, Geopotential Height, Relative Humidity, Specific Humidity, Omega (Vertical Velocity), U-Wind, and V-Wind are available on the second grid (2.5° x 2.5° horizontal resolution; 17 pressure levels).&lt;/li&gt;&#xA;&lt;li&gt;The variables Divergence, Specific Humidity, Virtual Air Temperature, and Relative Vorticity are available on the first grid (T62 Gaussian grid; 28 sigma layers). In order to calculate the model pressure at each sigma level, the surface pressure is additionally provided (T62 Gaussian grid but no vertical resolution). Also the topographic data (Orography) is provided on the same resolution as the surface pressure.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;2) The vertical layer representations by $\sigma$ coordinates, on the on side, and by a set of $A$, $B$ and $p_0$, on the other side, are similar to each other but not directly comparable to each other. However, for most &lt;em&gt;practical&lt;/em&gt; applications the data on the second grid, which is easier to handle, might be sufficient.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not sure if these answers to the question are satisfactory.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastEditorDisplayName="user1066" LastEditDate="2016-08-30T08:28:55.393" LastActivityDate="2016-08-30T08:28:55.393" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8132" PostTypeId="2" ParentId="8129" CreationDate="2016-06-08T10:01:07.323" Score="8" Body="&lt;p&gt;As Bon says, the mantle is solid, albeit somewhat viscous / plastic under the prevailing pressure and temperature conditions, so your hypothetical borehole isn't going to puncture any liquid magma chamber. Could it liquify if suddenly depressurized in a borehole? I doubt it, although it might do so if there was a local concentration of volatiles to depress the melting temperature. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the question is forever going to be hypothetical because there is no drill string capable of cutting into the lower crust, let alone the upper mantle. The heat would soften the drilling bit to the point where it was like putty. Also, the lateral rock pressure would be so high that the borehole walls would implode. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-08T10:01:07.323" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8133" PostTypeId="1" CreationDate="2016-06-08T10:18:08.807" Score="12" ViewCount="2111" Body="&lt;p&gt;Some oceans are very deep. But is there also current (convection) deep in the ocean so that all water molecules will ones be evaporated and fall down as rain or is it very quite at the bottom so some water molecules will stay at the bottom for decades?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="725" LastEditDate="2016-06-09T01:25:43.213" LastActivityDate="2018-01-23T22:37:54.077" Title="Are there water molecules in the oceans which will almost never fall down as rain?" Tags="|meteorology|geophysics|ocean|" AnswerCount="5" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8134" PostTypeId="2" ParentId="8133" CreationDate="2016-06-08T11:30:55.850" Score="14" Body="&lt;p&gt;&lt;em&gt;Never&lt;/em&gt; is a very, very long time.  &lt;em&gt;Almost never&lt;/em&gt; is a vague term.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The age of deep ocean water has been studied with both models and observations, and both indicate a lower limit age in the order of thousands of years, rather than decades.  Here, age is defined as &lt;em&gt;elapsed time since contact with the surface&lt;/em&gt;, which would be the only opportunity for evaporation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On a geological timescale, all ocean water has ample opportunity to evaporate and fall back as rain again and again.  On a human timescale, not so much: for some water in the ocean, it has been well over a thousand years since the last time it was near the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For an example of a recent study into the topic:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Gebbie and Huybers (2012): &lt;em&gt;The Mean Age of Ocean Waters Inferred from Radiocarbon Observations: Sensitivity to Surface Sources and Accounting for Mixing Histories&lt;/em&gt;.  in: Journal of Physical Oceanography.  &lt;a href=&quot;http://dx.doi.org/10.1175/JPO-D-11-043.1&quot;&gt;http://dx.doi.org/10.1175/JPO-D-11-043.1&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;From the abstract (emphasis mine):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A number of previous observational studies have found that the waters of the deep Pacific Ocean have an age, or elapsed time since contact with the surface, of 700–1000 yr. Numerical models suggest ages twice as old. Here, the authors present an inverse framework to determine the mean age and its upper and lower bounds given Global Ocean Data Analysis Project (GLODAP) radiocarbon observations, and they show that the potential range of ages increases with the number of constituents or sources that are included in the analysis.&#xA;  (...)&#xA;  The authors find that &lt;strong&gt;the North Pacific at 2500-m depth can be no younger than 1100 yr old&lt;/strong&gt;, which is older than some previous observational estimates.&#xA;  (...)&#xA;  Subject to the caveats that inference of the mixing history would benefit from further observations and that radiocarbon cannot rule out the presence of extremely old waters from exotic sources, &lt;strong&gt;the deep North Pacific waters are 1200–1500 yr old&lt;/strong&gt;, which is more in line with existing numerical model results.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2016-06-08T11:45:40.667" LastActivityDate="2016-06-08T11:45:40.667" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8135" PostTypeId="1" AcceptedAnswerId="8139" CreationDate="2016-06-08T18:03:25.870" Score="1" ViewCount="232" Body="&lt;p&gt;&lt;a href=&quot;http://climate.nasa.gov/vital-signs/global-temperature/&quot; rel=&quot;nofollow&quot;&gt;Nasa's temperature record&lt;/a&gt; is showing temperature increase. When I confronted a climate change skeptic with it, he replied that the data has been tempered with, and that there are different data sets which do not show temperature increase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The exact reply was:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;According to RSS, UAH and radiosonde global temp anomaly datasets,&#xA;  there hasn't been a global warming trend in 20 years;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;a href=&quot;http://www.woodfortrees.org/plot/rss/from:1996.6/to:2015.7/plot/rss/from:1996.6/to:2015.7/trend/plot/esrl-co2/from:1996.6/to:2015.7/normalise/trend/plot/esrl-co2/from:1996.6/to:2015.7/normalise&quot; rel=&quot;nofollow&quot;&gt;http://www.woodfortrees.org/plot/rss/from:1996.6/to:2015.7/plot/rss/from:1996.6/to:2015.7/trend/plot/esrl-co2/from:1996.6/to:2015.7/normalise/trend/plot/esrl-co2/from:1996.6/to:2015.7/normalise&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;GISS and HADCRUT4 datasets have added heat to raw temperature data to&#xA;  artificially keep the warming trend going as NOAA freely admits:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;a href=&quot;https://www.ncdc.noaa.gov/img/climate/research/ushcn/ts.ushcn_anom25_diffs_urb-raw_pg.gif&quot; rel=&quot;nofollow&quot;&gt;https://www.ncdc.noaa.gov/img/climate/research/ushcn/ts.ushcn_anom25_diffs_urb-raw_pg.gif&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This sounds reasonable to me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone familiar with climate science explain why there are several data-sets, and why they are saying different things, and why NASA's set is the correct one?&lt;/p&gt;&#xA;" OwnerUserId="5971" LastEditorUserId="106" LastEditDate="2016-06-09T10:38:19.097" LastActivityDate="2016-09-14T03:54:15.893" Title="Need different temperature change data sets explained" Tags="|climate|climate-change|climate-models|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8137" PostTypeId="2" ParentId="8104" CreationDate="2016-06-09T01:15:59.760" Score="1" Body="&lt;p&gt;Start with US Fish and wildlife services National Wetlands Inventory site.&#xA;Site has links to :&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.fws.gov/wetlands/Data/Mapper.html&quot; rel=&quot;nofollow&quot;&gt;Wetlands Mapper&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.fws.gov/wetlands/index.html&quot; rel=&quot;nofollow&quot;&gt;National Wetlands Inventory home page&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.fws.gov/wetlands/Status-and-Trends/index.html&quot; rel=&quot;nofollow&quot;&gt;Status and Trends web page&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.fws.gov/wetlands/Data/Data-Download.html&quot; rel=&quot;nofollow&quot;&gt;Download Seamless Wetlands Data&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2016-06-09T01:15:59.760" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8138" PostTypeId="2" ParentId="8133" CreationDate="2016-06-09T03:41:51.880" Score="4" Body="&lt;p&gt;Note that individual water molecules lifetimes that are much shorter than the ventilation timescales you are inquiring about. See&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.livescience.com/32254-does-a-water-molecule-have-a-lifespan.html&quot; rel=&quot;nofollow&quot;&gt;http://www.livescience.com/32254-does-a-water-molecule-have-a-lifespan.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.reddit.com/r/askscience/comments/1gk9gm/whats_the_lifetime_of_a_water_molecule/&quot; rel=&quot;nofollow&quot;&gt;https://www.reddit.com/r/askscience/comments/1gk9gm/whats_the_lifetime_of_a_water_molecule/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6024" LastActivityDate="2016-06-09T03:41:51.880" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8139" PostTypeId="2" ParentId="8135" CreationDate="2016-06-09T05:53:21.320" Score="6" Body="&lt;p&gt;There are several climate datasets around the world, two in America - NASA's GISTEMP, and NOAA's MLOST, and one in the UK - HadCRUT. These are the main datasets but there are others around the world, China, Japan etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The datasets differ slightly in the starting date, number of met stations included, degree of interpolation, and the way they get round the problem of lack of met stations in oceanic areas. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to being 'tampered with', this is a subtle malicious implication that the data has been fudged. It is also an insult to the scientific integrity of the thousands of climate scientists involved, whose aim, as in all of science, is to get at the truth. Of course, the data have been 'processed'. This is an essential part of data quality control to interpolate missing data, and to ensure consistency of the data set. But no data has been 'tampered with' in the sense of trying to lead to false conclusions.&#xA;One of the striking features of all the global datasets is that, despite minor differences, they all show the same basic characteristics of an accelerating global temperature - the 'hockey stick graph'. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is much dishonesty about, but not with the climate scientists. It is the climate skeptics who are being dishonest (not to mention scientifically incompetent). &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-09T05:53:21.320" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8141" PostTypeId="1" CreationDate="2016-06-09T12:35:11.833" Score="8" ViewCount="11676" Body="&lt;p&gt;Today driving to work I saw a small, isolated horse's mane cloud at about 2000 feet. Directly above it was a small strato-cumulous cloud at 4000 feet and and they were moving in opposite directions. The horse's mane was moving north and the strato-cumulous was moving south.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How could this happen?&lt;/strong&gt; I imagine there must have been two layers of air, each moving in a different direction. In fact there must have been &lt;em&gt;three&lt;/em&gt; layers of air, because the strato-cumulous would have been sitting on one layer and moving with the layer above.&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2019-03-07T17:08:50.547" Title="Clouds moving in opposite directions" Tags="|clouds|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8142" PostTypeId="2" ParentId="8141" CreationDate="2016-06-09T14:21:45.580" Score="3" Body="&lt;p&gt;This indicates that there was wind shear. Wind can change direction and speed with height. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since air is a fluid, it's wind vectors can change with height. On a large scale, this is called the thermal wind balance. In the ocean, it is Ekman balance. On smaller scales, there isn't really a term that I know of that describes the balance, because it is rather turbulent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as &quot;How could this happen&quot;: What you saw was the mean flow over the height of one cloud, followed by the mean flow over the depth of another cloud.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2016-06-09T14:21:45.580" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8143" PostTypeId="2" ParentId="7946" CreationDate="2016-06-09T17:10:20.087" Score="2" Body="&lt;p&gt;Precipitation is the results of physical processes. As each model implement convective and thermodynamic processes differently (mainly through parametrization or imposed by different grid cell resolution), each model will produce different precipitation. Hence, in other words, you can't tune precipitation, but you can tune the parameters that will produce precipitation. As rainfall is not an easy observable, especially in the period usually used for tuning (~1850-1900), climate modelers does not use such information for their tuning.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mauritsen et al. (2012) gives an interesting overview of this subject. The abstract is given below. From this article, it states (emphasis are mine) : &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;[...] Formulating and prioritizing our goals is challenging. To us, a &lt;strong&gt;global mean temperature&lt;/strong&gt; in close absolute agreement with observations is of highest priority because &lt;strong&gt;it sets the stage for temperature-dependent processes to act&lt;/strong&gt;. For this, we target the 1850–1880 observed global mean temperature of about 13.7 \deg C [Brohan et al., 2006]. Beyond that, we prioritize having &lt;strong&gt;globally averaged TOA shortwave absorption and outgoing longwave radiation in good agreement with satellite observations&lt;/strong&gt;, along with a &lt;strong&gt;representation of important climate variability modes&lt;/strong&gt;. [...]&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Abstract&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;During a development stage global climate models have their properties adjusted or tuned in various ways to best match the known state of the Earth’s climate system. These desired properties are observables, such as the radiation balance at the top of the atmosphere, the global mean temperature, sea ice, clouds and wind fields. The tuning is typically performed by adjusting uncertain, or even non-observable, parameters related to processes not explicitly represented at the model grid resolution. The practice of climate model tuning has seen an increasing level of attention because key model properties, such as climate sensitivity, have been shown to depend on frequently used tuning parameters. Here we provide insights into how climate model tuning is practically done in the case of closing the radiation balance and adjusting the global mean temperature for the Max Planck Institute Earth System Model (MPI-ESM). We demonstrate that considerable ambiguity exists in the choice of parameters,and present and compare three alternatively tuned, yet plausible configurations of the climate model. The impacts of parameter tuning on climate sensitivity was less than anticipated.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Citation&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mauritsen, Thorsten, Bjorn Stevens, Erich Roeckner, Traute Crueger, Monika Esch, Marco Giorgetta, Helmuth Haak, et al. 2012. “Tuning the Climate of a Global Model.” Journal of Advances in Modeling Earth Systems 4 (3): n/a – n/a. doi:10.1029/2012MS000154.&lt;/p&gt;&#xA;" OwnerUserId="757" LastActivityDate="2016-06-09T17:10:20.087" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8144" PostTypeId="2" ParentId="7939" CreationDate="2016-06-09T17:29:56.730" Score="4" Body="&lt;p&gt;The resolution of AO-GCM are not high enough to include lake model in their code, at least as far as I can remember (looking at google scholar, I have not found anything related to lake model in AOGCM).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, lake model are implemented (and operational) in regional climate model (RCM), such as CRCM5 (Canadian Regional Climate Model v5). See for example Martynov et al. (2012), where they describe the results of implementing lake model in a 45km resolution simulations. On that note, I think that until AOGCM (and now the Earth System Models, which implement carbone cycle) goes to resolution close to 50km, they won't adopt massively such lake models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From Martynov et al. (2012)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;The  presence  of  lakes  influences  mostly  the  lake-rich region of the Canadian Shield by altering the low-level  air  temperature,  humidity  and  precipitation.  The influence of lakes on the precipitation is most significant over   the   Laurentian   Great   Lakes   and   within   the distance  of  200-300  km  downstream  of  these  lakes,&#xA;especially  with  open  water  on  lakes  in  wintertime.  The patterns of enhanced precipitation correspond to regions of the well-known lake effect snow on downwind coasts of  the  Great  Lakes.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the effect is rather regional, I suspect that other climate processes are more important for the AOGCM modellers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Citations&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Martynov, Andrey, Laxmi Sushama, René Laprise, Katja Winger, and Bernard Dugas. 2012. “Interactive Lakes in the Canadian Regional Climate Model, Version 5: The Role of Lakes in the Regional Climate of North America.” Tellus A; Vol 64 (2012), February. &lt;a href=&quot;http://www.tellusa.net/index.php/tellusa/article/view/16226&quot; rel=&quot;nofollow&quot;&gt;http://www.tellusa.net/index.php/tellusa/article/view/16226&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On ResearchGate: &lt;a href=&quot;https://www.researchgate.net/publication/234872039_Interactive_Lakes_in_the_Canadian_Regional_Climate_Model_version_5_The_Role_of_Lakes_in_the_Regional_Climate_of_North_America&quot; rel=&quot;nofollow&quot;&gt;https://www.researchgate.net/publication/234872039_Interactive_Lakes_in_the_Canadian_Regional_Climate_Model_version_5_The_Role_of_Lakes_in_the_Regional_Climate_of_North_America&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="757" LastEditorUserId="757" LastEditDate="2016-06-09T19:26:03.430" LastActivityDate="2016-06-09T19:26:03.430" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8145" PostTypeId="1" CreationDate="2016-06-09T22:29:19.457" Score="4" ViewCount="204" Body="&lt;p&gt;I have conducted a brief survey of Internet sources and cannot locate any definite discussion of a possible connection between the Chicxulub impact and the inception or acceleration of the Rio Grande Rift and the possibly related Laramide Orogeny.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I looked at the related post &quot;can-impact-events-cause-widespread-volcanic-activity...&quot; but do not see a specific connection (since that involved primarily the antipodal hypothesis connecting the Deccan Traps with the impact). I note that a 2015 paper, &lt;a href=&quot;http://gsabulletin.gsapubs.org/content/early/2015/04/30/B31167.1.full.pdf&quot; rel=&quot;nofollow&quot;&gt;Triggering of the largest Deccan eruptions by the Chicxulub impact&lt;/a&gt; sets out a convincing argument that a pulse of mantle plume-head-derived magma fed the Wai Subgroup flows (in the Deccan Traps) and may have been triggered by dynamic stresses (Rayleigh waves) from the Chicxulub impact.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I read the Princeton University study &lt;a href=&quot;http://www.princeton.edu/main/news/archive/S31/90/32S94/&quot; rel=&quot;nofollow&quot;&gt;Princeton model shows fallout of a giant meteorite strike&lt;/a&gt; that was given in one of the answers to the SE post referred to above. That study corrected some of the misconceptions regarding the proposed strength of antipodal accumulation of impact seismic waves, however, their animation showed the expanding concentric impact wave passing directly under the crust where the Laramide Orogeny uplift and the Rio Grande Rift spreading had either begun or began shortly thereafter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The 2015 paper given above (Triggering....by Chicxulub) estimates generated seismic energy densities on the order of 0.1 - 1.0 J/$m^3$ throughout the upper 200 km of the mantle, sufficient to trigger volcanic eruptions worldwide based on historical examples. They go on to hypothesize that triggering of other events (like the Deccan Trap flows) might have been caused by transient increase in effective permeability of an existing deep magmatic system (&quot;mantle plume head&quot;). In fact, they refer to the Princeton model (Meschede et al 2011; link above) in estimating the 1000 - 3000 km (from epicenter of impact; 3200 km is the approximate distance to the Rio Grande Rift) energy density from Chicxulub at 0.1 - 1 J/$m^3$ (in their figure 4 in the 2015 paper already noted). This would be the energy density in the concentric wave (view the Princeton animation at the link given) passing directly under the Rio Grande Rift and Laramide Orogeny area (the latter the more easterly area under southern present day New Mexico, which was uplifted somewhat while the Rockies were raised).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is already hypothesized that the Rio Grande Rift and Laramide Orogeny (the dating on those two processes are not well fixed, but seem to be near the end of the Cretaceous, i.e., around the time of the Chicxulub impact) likely involved existing pressures from the western subduction of the Kula and Farallon Plates already under the North American Plate as well as shallow oceanic crust subduction of the Pacific Plate. With the region inland already experiencing one or more magma plumes (the Socorro, New Mexico, region, i.e., Socorro-Magdalena caldera cluster of the central Rio Grande rift, hosts an inflating mid-crustal sill-like magma body at a depth of 19 km that is responsible for anomalously high earthquake activity in the vicinity continuing today, per Wikipedia), it seems very possible that the Chicxulub impact may have triggered or accelerated the Rio Grande Rift and also the uplift in the area due to the Laramide Orogeny uplift.&lt;/p&gt;&#xA;" OwnerUserId="6120" LastEditorUserId="6120" LastEditDate="2016-06-09T23:21:29.180" LastActivityDate="2017-12-14T14:05:50.683" Title="Can non-antipodal Chicxulub impact seismic wave be connected to Rio Grande Rift and Laramide Orogeny?" Tags="|geodynamics|seismic|mantle-plumes|continental-rifting|impacts|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8147" PostTypeId="1" AcceptedAnswerId="8155" CreationDate="2016-06-10T01:14:23.873" Score="8" ViewCount="8155" Body="&lt;p&gt;Both seem to be a study of a planet's surface. Topography seems to have more to do with the graphical depiction of surface features, but there seems to be a lot of overlap...&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2021-06-20T14:48:39.590" Title="What's the difference between topography and orography?" Tags="|topography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8148" PostTypeId="2" ParentId="8141" CreationDate="2016-06-10T01:53:49.870" Score="3" Body="&lt;p&gt;Pressure gradients cause movement of air, i.e. wind. Wind blows from high pressure to low pressure. Wind can be looked at as a vector quantity. It has magnitude and direction.&#xA;What you saw was due to the fact that the direction of the wind at 2000 feet was different from the direction of the wind at 4000 feet. This is called wind shear (vertical wind shear in this case since we are concerned with the difference in the vertical direction.)&#xA;Wind shear can be caused my many different phenomenon, such as:&#xA;A frontal passage (sharp gradient in the temperatures of the air in the horizontal direction).&#xA;Temperature inversion (temperature usually decreases as you increase altitude, but in some case, over a layer of the atmosphere, it can increase)&#xA;&lt;a href=&quot;https://i.stack.imgur.com/LdQyQ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LdQyQ.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Warm air has lower density (molecules have more energy and are bouncing around with greater intensity and speed) than cold air, a warm air pocket next to a cold air pocket causes a horizontal pressure gradient and wind to blow, if there's a pocket of hot air (due to a temperature inversion) above the cold air pocket, the reverse will begin to happen (over a layer, you will see that the red has move to the right and blue to the left) and you will see wind blowing in the opposite direction due to the new pressure gradient.&lt;/p&gt;&#xA;&lt;p&gt;Thermal wind is a meteorological term (not referring to an actual wind), but a difference in the wind between two pressure levels; in essence, wind shear.&lt;/p&gt;&#xA;" OwnerUserId="552" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-03-05T18:40:18.840" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="8149" PostTypeId="2" ParentId="7290" CreationDate="2016-06-10T02:09:35.163" Score="1" Body="&lt;p&gt;The Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) satellite provides new insight into the role that clouds and atmospheric aerosols (airborne particles) play in regulating Earth's weather, climate, and air quality.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;CALIPSO combines an active lidar instrument with passive infrared and visible imagers to probe the vertical structure and properties of thin clouds and aerosols over the globe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data from the satellite can be found here (&lt;a href=&quot;https://eosweb.larc.nasa.gov/project/calipso/calipso_table&quot; rel=&quot;nofollow&quot;&gt;https://eosweb.larc.nasa.gov/project/calipso/calipso_table&lt;/a&gt;), from what I see, the latest dataset is about a week old. While this won't give you the cloud type, it will surely give you the cloud heights, you will have to apply some knowledge though to differentiate between clouds and aerosols. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the cloud type, I suggest you can look at visible satellite data or infrared satellite data to look at clouds and judge the cloud type.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the e-wall from Penn State, &#xA;&lt;a href=&quot;http://mp1.met.psu.edu/~fxg1/ewall.html&quot; rel=&quot;nofollow&quot;&gt;http://mp1.met.psu.edu/~fxg1/ewall.html&lt;/a&gt;&#xA;If you look at the left panel about mid-page, you see the heading 'Satellite' and you can look at the visible and infrared spectrum and also a water vapor satellite image.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This approach seems very raw, but this is what I could remember off the top of my head. I don't know of a page that provides real time data about cloud height and cloud type.&lt;/p&gt;&#xA;" OwnerUserId="552" LastActivityDate="2016-06-10T02:09:35.163" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8150" PostTypeId="1" CreationDate="2016-06-10T02:30:24.243" Score="4" ViewCount="839" Body="&lt;p&gt;Most of us know that the ozone layer gets depleted due to green house gasses and other factors. Which made me wonder, is there any natural phenomenon that causes an increase in ozone?&lt;/p&gt;&#xA;" OwnerUserId="5395" LastEditorUserId="543" LastEditDate="2016-06-10T19:00:30.277" LastActivityDate="2016-06-20T20:58:33.050" Title="What natural phenomena increase stratospheric ozone?" Tags="|geochemistry|planetary-science|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8151" PostTypeId="1" AcceptedAnswerId="8169" CreationDate="2016-06-10T06:52:12.907" Score="6" ViewCount="5462" Body="&lt;p&gt;We all know that deserts are the hottest places on Earth, but what makes them different from other parts of the world?&lt;/p&gt;&#xA;" OwnerUserId="5395" LastEditorUserId="725" LastEditDate="2016-06-10T08:52:03.307" LastActivityDate="2016-06-12T04:27:20.193" Title="Why are deserts hotter than other places on Earth" Tags="|meteorology|atmosphere|climate|temperature|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8152" PostTypeId="1" CreationDate="2016-06-10T08:38:56.220" Score="2" ViewCount="26" Body="&lt;p&gt;I have zircons that have been mounted in a resin block. They have been polished to approximately half way through the zircons (as is convention) and they have been ablated to attain the U-Pb or Pb-Pb ages. I am unfamiliar with the intricacies of the (U+Th)/He method. Can these zircons still be analysed for (U+Th)/He? Or would the ablation affect the results? Furthermore, would the zircons need to be extracted from the resin blocks? If so, what would be the best method of extraction?&lt;/p&gt;&#xA;" OwnerUserId="6083" LastActivityDate="2016-06-10T08:38:56.220" Title="Can zircons be analysed by the (U+Th)/He after being ablated for analysis of U-Pb?" Tags="|geology|geochemistry|geochronology|isotopic|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8153" PostTypeId="2" ParentId="8151" CreationDate="2016-06-10T09:37:23.283" Score="6" Body="&lt;p&gt;The first thing to note is that not all deserts are hot - think Tibet.&#xA;But there is no doubt that most deserts are distributed adjacent to the hot and wet climatic equator. This is no coincidence. Because the sun is at or close to being overhead in the equatorial zone, this belt receives the most solar energy per square metre. Hot air rises, dumping a lot of the moisture as it cools (hence tropical rain forests), then the air spreads out polewards in both north and south directions, flowing in the upper troposphere. Pressure distribution is such that this part of the global circulation is balanced by a return air flow close to ground level. Together this convective air circulation occurs in 'Hadley Cells' which constitutes the world's biggest heat re-distribution mechanism. The downflow part of the cells is where hot dry air descends under clear skies, and hence is where deserts occur. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-10T09:37:23.283" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8155" PostTypeId="2" ParentId="8147" CreationDate="2016-06-10T12:26:57.787" Score="8" Body="&lt;p&gt;&lt;strong&gt;Topography&lt;/strong&gt;, in the eyes of Earth Scientists, is the study of the surface features of the Earth (or other planet), and includes all features of that surface, natural or artificial.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the Oxford Dictionary:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;1.The arrangement of the natural and artificial physical features of an area&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Topography comes from the Greek &lt;em&gt;topos&lt;/em&gt;, meaning 'place'. It is a study of all the features of any specific area, not necessarily just elevation, as depicted in topographical maps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Orography&lt;/strong&gt; is a specific study of the features and 'topography' of mountains:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;The branch of physical geography dealing with the formation and features of mountains&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Comes from the Greek &lt;em&gt;óros&lt;/em&gt; meaning 'hill'. Orography can also be known as orology, oreography or oreology... It is concerned with the formation and development of mountains, hills and ranges, for example the formation of a mountain range or ranges is know as an 'Orogeny'. Earth Scientists can refer to groups of mountains or ranges as 'Orogens'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Orography falls more broadly under the study of &lt;strong&gt;Geomorphology&lt;/strong&gt;, which is not necessarily just constrained to surface features, as in the case of topography.&lt;/p&gt;&#xA;" OwnerUserId="5209" LastActivityDate="2016-06-10T12:26:57.787" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8156" PostTypeId="2" ParentId="7954" CreationDate="2016-06-10T14:32:08.643" Score="3" Body="&lt;p&gt;After looking at the source from nrmima.nrm.se/IMA_Master_List_2016-03.pdf, I discovered the:&#xA;IMA Database of Mineral Properties&#xA;Created and maintained by the RRUFF Project in partnership with the IMA&#xA;&lt;a href=&quot;http://rruff.info/ima/&quot; rel=&quot;nofollow&quot;&gt;http://rruff.info/ima/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I downloaded all the minerals in a csv file.  This worked very well for two reasons.  First they had various chemical formula formats that were favorable for entry into a database.  Second they had a mineral group column.  The mineral group column was very important since often in the field the exact mineral is not noted but a group such as chlorite or garnet.  I will worry about Strunz or Dana numbers/codes at a later date.&lt;/p&gt;&#xA;" OwnerUserId="5940" LastActivityDate="2016-06-10T14:32:08.643" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8157" PostTypeId="1" CreationDate="2016-06-10T15:10:31.460" Score="1" ViewCount="53" Body="&lt;p&gt;Is there anyone who have some academic references on reforestation project in Samboja Lestari?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I could not find any case study on Samboja Lestari, on how climate changed in this area (especially about microclimate)?&lt;/p&gt;&#xA;" OwnerUserId="2827" LastEditorUserId="725" LastEditDate="2016-06-12T22:53:30.093" LastActivityDate="2016-06-12T22:53:30.093" Title="Reforestation project in Samboja Lestari, Indonesia" Tags="|forest|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8158" PostTypeId="2" ParentId="8150" CreationDate="2016-06-10T15:19:01.343" Score="0" Body="&lt;p&gt;Yes, there are ways of regenerating atmospheric ozone. Generally, you need an oxygen atom and an oxygen molecule to react to form ozone (as well as something to take off excess energy). The generation of the oxygen atom has a couple pathways, but near the surface, it is mostly generated from the photolysis of nitrogen dioxide.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2016-06-10T22:07:57.170" LastActivityDate="2016-06-10T22:07:57.170" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8160" PostTypeId="1" CreationDate="2016-06-10T19:25:16.350" Score="2" ViewCount="33" Body="&lt;p&gt;If I am looking at different USGS stream gages, calculating their 90th percentile streamflow, and then doing a weighted average of the 90th percentile of the streamflows using the watershed areas - what average watershed area represents this estimate?  The normal arithmetic mean?  Or some other mean?&lt;/p&gt;&#xA;" OwnerUserId="2714" LastActivityDate="2016-06-10T19:25:16.350" Title="Averaging watershed areas" Tags="|hydrology|water|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8161" PostTypeId="2" ParentId="8150" CreationDate="2016-06-10T20:17:03.363" Score="5" Body="&lt;p&gt;Like BarocliniCplusplus said, ozone is generated when you have a single free oxygen atom. This can come from photolysis of O2 in the upper stratosphere, or photolysis of ozone itself, or photolysis of NO2 in the troposphere. The stratosphere gets its NO2 from the breakdown of N2O by other radical species. But NO and NO2 both react with ozone, typically destroying it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if you want a natural process that would enhance ozone, I would look for a process that reduces the amount of N2O (or other ozone-depleting species) reaching the stratosphere. N2O is produced by bacteria in soils, so anything that suppresses that production -- especially in the tropics -- would enhance stratospheric ozone. Carbonyl sulfide (OCS) is another species that only photolyzes in the stratosphere and depletes ozone; its concentrations would similarly decrease if there were a decrease in transfer of it from ocean to atmosphere (it's a product of plankton). You could also have a meteorological effect that suppresses deep convection in the tropics, though I can't offhand think of what this would be.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you're interested in understanding the specifics a bit more (I'm not great at summarizing all of the cycles involved), I recommend checking out &lt;a href=&quot;http://acmg.seas.harvard.edu/people/faculty/djj/book/bookchap10.html&quot; rel=&quot;noreferrer&quot;&gt;http://acmg.seas.harvard.edu/people/faculty/djj/book/bookchap10.html&lt;/a&gt;. Daniel Jacob is a pretty influential atmospheric chemist, and he put his whole book online.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NB: NO2 destroys ozone in the stratosphere, but typically enhances ozone in the troposphere. This is because the troposphere has much, much higher concentrations of organic species and the hydroxyl (OH) radical. Instead of depleting O3, the NO produced when NO2 photolyzes can react with HO2 to re-form NO2 and OH, so the ozone-depleting nature of NO is reduced. Since that process re-forms OH, OH can attack organic species and leave the H radical, which then pulls in O2 to form HO2, which will later end up producing an odd oxygen and thus form ozone. (Sorry if this is a bit rambly. I haven't tried to summarize all of this before, so let me know what things are confusing.)&lt;/p&gt;&#xA;" OwnerUserId="1342" LastActivityDate="2016-06-10T20:17:03.363" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8162" PostTypeId="2" ParentId="8135" CreationDate="2016-06-10T20:29:53.887" Score="2" Body="&lt;p&gt;Gordon Stanger's reply is the correct answer to this question, but I wanted to point out something else. Saying that there &quot;hasn't been a global warming trend in 20 years&quot; is a tricky statement to begin with. There are a number of papers discussing it, but I think this one is a good summary:&lt;br&gt;&#xA;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2009GL037810/abstract;jsessionid=0D260FA124707D1AD055454F9C2FBAB4.f01t03&quot; rel=&quot;nofollow&quot; title=&quot;Is the climate warming or cooling?&quot;&gt;Is the climate warming or cooling?&lt;/a&gt;&lt;br&gt;&#xA;Essentially, the point is that climate is variable enough that you can get decades of no trend or even slight global cooling; but the longer-term trends &lt;em&gt;always&lt;/em&gt; show warming. Where you choose to start and end your regression line to calculate a trend is an easy way to get whatever answer you want. To quote their abstract:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Numerous websites, blogs and articles in the media have claimed that the climate is no longer warming, and is now cooling. Here we show that periods of no trend or even cooling of the globally averaged surface air temperature are found in the last 34 years of the observed record, and in climate model simulations of the 20th and 21st century forced with increasing greenhouse gases. We show that the climate over the 21st century can and likely will produce periods of a decade or two where the globally averaged surface air temperature shows no trend or even slight cooling in the presence of longer-term warming.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="1342" LastActivityDate="2016-06-10T20:29:53.887" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8164" PostTypeId="2" ParentId="8151" CreationDate="2016-06-11T00:11:53.350" Score="4" Body="&lt;p&gt;Hot deserts are usually in a location where several factors are all occurring together:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the elevation is near sea level (this ensures enough atmospheric heating)&lt;/li&gt;&#xA;&lt;li&gt;the latitude is not near the poles (not enough sunlight)&lt;/li&gt;&#xA;&lt;li&gt;the location is not in the path of any seasonal rainstorms (e.g. in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Rain_shadow&quot; rel=&quot;nofollow&quot;&gt;rain shadow&lt;/a&gt; of mountain ranges: rain clouds predominantly come from one direction and orographic rainfall occurs on only one side of the range )&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Furthermore, you can read &lt;a href=&quot;https://en.wikipedia.org/wiki/Desert&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Deserts are formed by weathering processes as large variations in temperature between day and night put strains on the rocks which consequently break in pieces. Although rain seldom occurs in deserts, there are occasional downpours that can result in flash floods. Rain falling on hot rocks can cause them to shatter and the resulting fragments and rubble strewn over the desert floor is further eroded by the wind. This picks up particles of sand and dust and wafts them aloft in sand or dust storms. Wind-blown sand grains striking any solid object in their path can abrade the surface. Rocks are smoothed down, and the wind sorts sand into uniform deposits. The grains end up as level sheets of sand or are piled high in billowing sand dunes. Other deserts are flat, stony plains where all the fine material has been blown away and the surface consists of a mosaic of smooth stones. These areas are known as desert pavements and little further erosion takes place. Other desert features include rock outcrops, exposed bedrock and clays once deposited by flowing water. Temporary lakes may form and salt pans may be left when waters evaporate. There may be underground sources of water in the form of springs and seepages from aquifers. Where these are found, oases can occur.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastActivityDate="2016-06-11T00:11:53.350" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8165" PostTypeId="1" CreationDate="2016-06-11T02:47:46.570" Score="1" ViewCount="125" Body="&lt;p&gt;In the laboratory we can maintain the low level temperature like 0 to -13 degrees.&#xA;Like that can we do this process in atmosphere. For instance atmosphere temperature is 35 degrees can we change the temperature to 20 degrees or 50 degrees? Is it possible or not? If it's possible how can we do that?  &lt;/p&gt;&#xA;" OwnerUserId="6123" LastEditorDisplayName="user1066" LastEditDate="2016-06-11T03:03:03.480" LastActivityDate="2016-06-11T09:50:53.037" Title="Can we change the temperature in atmosphere?" Tags="|meteorology|temperature|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8166" PostTypeId="2" ParentId="8165" CreationDate="2016-06-11T09:50:53.037" Score="2" Body="&lt;p&gt;You are talking about terra-forming on a global scale. To cool the entire atmosphere would result in two separate amounts of energy, one would be the thermal energy removed from the atmosphere, and the other would be the energy expended in the process. Both would be astronomic in magnitude, and orders of magnitude more than all previous components of the anthropic energy balance. How and where would we store such prodigious quantities of energy? Also, it would cost more than the gross economic product of the planet. And would it solve the problem? No, quite the reverse. It would only add to the greenhouse gas emissions. Even if we cooled the planet by 20 degrees, it would only be a matter of time before thermal equilibrium with respect to the atmospheric CO2 and water vapour would be regained. So there would be no long-term gain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to cool the planet significantly we would have to reduce carbon emissions to practically nothing, and then use carbon capture and storage to depress global CO2 from the current 404 ppm to about 320 ppm. If we could do that in time for the next Milankovitch glacial entry point (an orbital feature), then there is a reasonable chance than we could put Earth back into 'glacial mode'. But as time goes by, this gets less and less likely. By the time we double CO2 relative to the pre-industrial era,  another glacial epoch looks highly unlikely. By the time we triple the CO2, we can kiss goodbye to glaciation for ever. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-11T09:50:53.037" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8167" PostTypeId="1" CreationDate="2016-06-11T13:02:53.370" Score="1" ViewCount="376" Body="&lt;p&gt;I heard on Star Talk Radio that Jupiter has weather systems larger than Earth so I was just curious to know what the definition of a weather system is exactly.&lt;/p&gt;&#xA;" OwnerUserId="6130" LastActivityDate="2016-06-11T13:02:53.370" Title="What is a weather system?" Tags="|meteorology|climate|planetary-science|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8168" PostTypeId="2" ParentId="8054" CreationDate="2016-06-11T21:20:37.817" Score="1" Body="&lt;p&gt;I'm confused about your misunderstanding as the answer to your question is in the Wikipedia link you posted:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Regions receive a two-digit code. The following levels are designated&#xA;  by the addition of another two digits.[8] The hierarchy was designed&#xA;  and the units subdivided so that almost all the subbasins (formerly&#xA;  called cataloging units) are larger than 700 square miles (1,800 km2).&#xA;  Larger closed basins were subdivided until their subunits were less&#xA;  than 700 square miles.[7] The 10-digit watersheds were delineated to&#xA;  be between 40,000 and 250,000 acres in size, and the 12-digit&#xA;  subwatersheds between 10,000 and 40,000 acres.[6] In addition to the&#xA;  hydrologic unit codes, each hydrologic unit was assigned a name&#xA;  corresponding to the unit's principal hydrologic feature or to a&#xA;  cultural or political feature within the unit.[7]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, once you are outside of the 2 digit regions, HUC boundaries (or dividing/outlet points along a continuous stream) that separate an upstream watershed from one a downstream one (that should incorporate the upstream HUC using the classic definition of a watershed) are set to evenly divide up the larger (or containing) HUC. &lt;/p&gt;&#xA;" OwnerUserId="2714" LastActivityDate="2016-06-11T21:20:37.817" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8169" PostTypeId="2" ParentId="8151" CreationDate="2016-06-12T04:27:20.193" Score="7" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;We all know that deserts are the hottest places on Earth.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;That is not necessarily true. What is true is that the hottest places on Earth are in deserts. Note the reversal. Much of the Arctic and Antarctic are technically deserts due to extremely low precipitation. Excluding these polar deserts, some deserts are quite cool, even if they are close to the equator. For example, Arica, Chile (the driest inhabited locale in the world), has a rather mild climate temperature-wise, despite being at 18°29′ south latitude. This is the case for much of the Atacama desert.&lt;/p&gt;&#xA;&lt;br&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;What makes them different from other parts of the world?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I'm assuming you are asking about those deserts that are hot in the summertime rather than deserts in general. A key ingredient for extremely high temperatures is a desert, but not a high latitude desert, high altitude desert, or coastal desert.&lt;/p&gt;&#xA;&lt;p&gt;Very low precipitation is what distinguishes desert from non-desert biomes. Lack of precipitation is not sufficient for very high temperatures, as exhibited by the very cold polar deserts and the rather cool deserts that are well outside polar areas. Much of the Atacama is at a high altitude, as are the Gobi in China and Mongolia, the Taklamakan in China, and the high desert in the Mexico and the US. While some of these deserts can be hot during summer, they aren't ridiculously hot. Areas along the coast of the previously mentioned Atacama desert and the Namib in Africa are kept somewhat cool by ocean breezes. These coastal deserts can be uniformly mild year-round.&lt;/p&gt;&#xA;&lt;p&gt;What is needed to create the possibility for extremely high temperatures is a desert that is not at extreme latitudes, that is well removed from coastal cooling, and that is at low altitudes. A desert is needed so as to receive the full brunt of solar radiation. Equatorial regions don't work because they tend to be cloudy and rainy. High latitude areas don't work because they don't receive very much insolation. High altitude areas don't work because temperature tends to decrease with increased altitude.&lt;/p&gt;&#xA;&lt;p&gt;A low altitude desert in the horse latitudes is exactly what is needed, and this is why Furnace Creek in Death Valley, California (supposedly the hottest place in the world) and Tirat Zvi, Isreal (supposedly the hottest place in Asia) can be very, very hot. The horse latitudes are where the Hadley cell and mid latitude cell converge, creating long-lived high pressure areas where rain is highly unlikely. Most of the world's non-polar deserts are in or near the horse latitudes.&lt;/p&gt;&#xA;&lt;p&gt;Even better than Furnace Creek are those areas that are so ridiculously hot that nobody sane would live there and hence there are no weather stations. We don't know, for example, how hot it gets in the Lut desert in Iran. It's too hot there for people to fathom, and is almost certainly hotter than is Furnace Creek.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-06-12T04:27:20.193" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8170" PostTypeId="1" AcceptedAnswerId="8174" CreationDate="2016-06-12T14:16:14.327" Score="4" ViewCount="4721" Body="&lt;p&gt;As it is described (W. M. White, Geochemistry): &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;Siderophile elements have an affinity for a metallic liquid phase&lt;/em&gt;&#xA;  and &#xA;  &lt;em&gt;chalcophile elements have an affinity for a sulfide liquid&#xA;  phase.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What is the exact difference between them? It just seems to be the same thing as sulfide liquid must contain metals as well. As far as I know, siderophile elements are: Fe, Co, Ni etc and chalcophile ones are Ar, Mg, Sr, Ba etc.&lt;/p&gt;&#xA;" OwnerUserId="5529" LastEditorUserId="725" LastEditDate="2016-06-12T23:06:19.330" LastActivityDate="2024-01-16T21:29:15.457" Title="What is the difference between chalcophile and siderophile elements?" Tags="|geochemistry|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8171" PostTypeId="2" ParentId="8133" CreationDate="2016-06-12T17:07:17.783" Score="2" Body="&lt;p&gt;Maybe I am very far from to be an earth scientist :-), but here are some laymans calculations based on the available data.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The land area of the Earth is around 148million km^2 (&lt;a href=&quot;http://www.universetoday.com/25756/surface-area-of-the-earth/&quot; rel=&quot;nofollow&quot;&gt;ref&lt;/a&gt;).&lt;/li&gt;&#xA;&lt;li&gt;The mean yearly rain on land is around 715mm (&lt;a href=&quot;https://en.wikipedia.org/wiki/Rain&quot; rel=&quot;nofollow&quot;&gt;ref&lt;/a&gt;).&lt;/li&gt;&#xA;&lt;li&gt;(1) and (2) means a total volume of yearly rain on land around 148e+6 * 715e-6 = 105820 km^3.&lt;/li&gt;&#xA;&lt;li&gt;The total area of the World in around 510072000 km^2 (&lt;a href=&quot;http://chartsbin.com/view/wwu&quot; rel=&quot;nofollow&quot;&gt;ref&lt;/a&gt;).&lt;/li&gt;&#xA;&lt;li&gt;(1) and (4) means a total water area of around 362 million km^2.&lt;/li&gt;&#xA;&lt;li&gt;Average overall depth of the world Oceans is 3800 m (&lt;a href=&quot;http://hypertextbook.com/facts/2006/HelenLi.shtml&quot; rel=&quot;nofollow&quot;&gt;ref&lt;/a&gt;).&lt;/li&gt;&#xA;&lt;li&gt;(5) and (6) means a 1375.6 million km^3 of the total volume of the world oceans.&lt;/li&gt;&#xA;&lt;li&gt;(3) and (7) means a time constant of around 1376.6/0.105820 = 13000 years for the &lt;a href=&quot;https://en.wikipedia.org/wiki/Time_constant&quot; rel=&quot;nofollow&quot;&gt;time constant&lt;/a&gt; of the exchange of waters by rainfall to the land area of the world oceans.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;(8) would also mean, that after every 13000 years, around 63% (1-1/e) of the water molecules of the World's oceans evaporate and falls as rain into the land - &lt;em&gt;if the evaporation would happen with the same ratio in the whole volume of the world oceans&lt;/em&gt;. Which is clearly not true - there are deep areas without nearly every underwater stream or any similar. But - considering the other replies - their exchange by underwater streams is much faster as this 13000 years, so we can consider them negligible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider that the world oceans exists since around 4.4 billion years. It is around 338462 times of the time constant of the rain exchange. This would mean, that around 1/e^338462 part of the water molecules of the World didn't fall as rain until now. It is around 10^-146992 .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now consider that the number of the protons in the visible Universe is around 10^85.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This 10^146992 is so many times bigger as even the number of the protons in the whole visible universe, that even considering the minor inaccuracies in this calculation, or considering the quasi-stable deep ocean regions (which were detailed by the previous answers), we can surely say:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;There is no water molecule on the world oceans which wouldn't ever fallen as rain somewhere to a surface area.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6016" LastActivityDate="2016-06-12T17:07:17.783" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8174" PostTypeId="2" ParentId="8170" CreationDate="2016-06-12T23:38:25.513" Score="5" Body="&lt;p&gt;First, a small correction: Fe, Co and Ni and considered siderophile. Mg, Sr and Ba are lithophile. Ar is atmophile.&lt;/p&gt;&#xA;&lt;p&gt;Here's one version of the classification, just in case you need to have it in front of your eyes: &lt;a href=&quot;https://i.stack.imgur.com/WG8A1.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WG8A1.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;sup&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Goldschmidt_classification&quot; rel=&quot;nofollow noreferrer&quot;&gt;source: the Wikipedia article on Goldschmidt classification&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;What is the exact difference between them? It just seems to be the&#xA;same thing as sulfide liquid must contain metals as well.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is a bit confusing because most siderophile metals are also chalcophile or even lithophile. Let's begin by defining what are metal and sulfide liquids in the Earth.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Metal liquid&lt;/strong&gt;: Siderophile elements are concentrated in molten Fe. Not just any metal, but specifically molten Fe. This is truly molten metal, where most of the atoms are neutral, the bonding is metallic, and there are no ionic bonds. The only place that a liquid like this exists to any significant proportion today is Earth's outer core.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Sulfide liquid&lt;/strong&gt;: Chalcophile elements are concentrated in molten sulfide. In the Earth this will mostly be Fe-rich sulfide, the liquid analogue of pyrrhotite and pentlandite (known as mss in high temperature). Sulfide liquids can also form from crystallizing magmas when the liquid phase becomes saturated and a separate, immiscible sulfide liquid precipitates. This precipitated liquid too is likely to contain iron as well as chalcophile metals. This liquid is dominated by the presence of sulfide as S&lt;sup&gt;2-&lt;/sup&gt;. This is no longer a metallic liquid with neutral atoms. This is a liquid where the bonding character is a combination of ionic (because you got Fe&lt;sup&gt;2+&lt;/sup&gt;, Ni&lt;sup&gt;2+&lt;/sup&gt; and S&lt;sup&gt;2-&lt;/sup&gt;), metallic and covalent. Sulfide liquids can exist in the core (we do not know), but they exist in the mantle and the crust where they are how you move the chalcophile (and siderophile) elements around. Ore deposits of these elements almost always form from sulfide liquids, or their alteration products.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Because of the contrasting bonding properties of the metallic and sulfide liquids, trace elements partition differently to them. For example, Te and Cu will &amp;quot;feel more comfortable&amp;quot; in sulfide liquid, whereas Ir and Au will prefer the liquid Fe metal.&lt;/p&gt;&#xA;&lt;p&gt;How does this fit in the bigger picture? The main importance of the siderophile-element category is that there are not enough of them. When you look at how much siderophile elements there are in the solar system, and then compare to how much we have in the crust and mantle, there are not enough. This is especially true for the highly siderophile elements (HSE: Au, Re, Ru, Rh, Pd, Os, Ir, Pt). This is unfortunate, because these are very useful metals. We could all use some more Au, Pt and Ir. The accepted explanation is that when the Earth formed, the liquid Fe metal that sunk to the core scavenged the siderophile elements from the surrounding silicate (lithophile-bearing) magma ocean and locked them in the core, far away from us.&lt;/p&gt;&#xA;&lt;p&gt;But this occurred a very long time ago, and has little relevance for moving the siderophile elements around in more recent times, and in places closer to us. In the absence of liquid metal, siderophile elements actually behave as chalcophiles or lithophiles. Ore deposits of HSE and particularly the platinum group elements (Ru, Rh, Pd, Os, Ir, Pt) occur in sulfides. Iron, the namesake of the siderophiles, commonly occurs as oxide minerals or as a component of mafic silicates, giving it a lithophile character.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="20607" LastEditDate="2024-01-16T21:29:15.457" LastActivityDate="2024-01-16T21:29:15.457" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="8177" PostTypeId="1" CreationDate="2016-06-13T21:08:49.673" Score="4" ViewCount="7594" Body="&lt;p&gt;One side of the Earth is almost completely covered with water (the Pacific), while landmass is almost all on the other side. Is this coincidence or plays there something else? This difference is not as pronounced as the difference between North and South.&lt;/p&gt;&#xA;" OwnerUserId="5945" LastEditorUserId="5945" LastEditDate="2016-06-17T21:29:23.763" LastActivityDate="2016-06-17T21:29:23.763" Title="Why is almost all the landmass on one side of the globe?" Tags="|geology|plate-tectonics|" AnswerCount="2" CommentCount="3" ClosedDate="2016-06-15T16:00:13.403" ContentLicense="CC BY-SA 3.0" />
  <row Id="8178" PostTypeId="1" CreationDate="2016-06-14T03:43:01.387" Score="6" ViewCount="3229" Body="&lt;p&gt;I remember reading somewhere that there's evidence of water on Mars but it all sank into the Martian soil. So what prevents that happening on earth?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some people say it's because the crust is not permeable to water, but that must be nonsense because of volcanic actions and earthquakes, there certainly will be cracks that allow water to flow through. So the only thing that prevents the water from sinking in is the temperature, right?&lt;/p&gt;&#xA;" OwnerUserId="6140" LastEditorUserId="725" LastEditDate="2016-06-14T20:51:22.307" LastActivityDate="2019-01-12T13:10:12.410" Title="What keeps water from sinking into earth?" Tags="|geology|hydrology|water|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8179" PostTypeId="1" CreationDate="2016-06-14T06:22:46.117" Score="6" ViewCount="1247" Body="&lt;p&gt;I teach a Middle School (year 8) Geometry course and have a student attempting to answer this question. My assumptions:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;earth's radius is $3959 \text{ mi}$&lt;/li&gt;&#xA;&lt;li&gt;earth is a sphere&lt;/li&gt;&#xA;&lt;li&gt;There is approximately $3 \cdot 10^{15}$ kg of CO&lt;sub&gt;2&lt;/sub&gt; in earth's atmosphere&lt;/li&gt;&#xA;&lt;li&gt;The density of CO&lt;sub&gt;2&lt;/sub&gt; at 1atm is $\dfrac{1562 \text{ kg}}{\text{cubic meter}}$&lt;/li&gt;&#xA;&lt;li&gt;Conversion between cu meters and cu ft are $1:35.3147$. And cu ft to cu mi is $5280^3:1$&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;So, first, with assumption (3 and 4) we can compute the volume of CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere to be $\approx 1.92 \cdot 10^{12} \text{ m}^3$ or about $369 \text{ cu mi}$ of CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, now we can find the thickness of the layer by solving the equation&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\begin{align*}&#xA;369 &amp;amp;= \dfrac{4 \pi \cdot (3959 + x)^3}{3} - \dfrac{4 \pi (3959)^3}{3} \\&#xA;\end{align*}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where $x$ is the thickness of the layer of CO&lt;sub&gt;2&lt;/sub&gt; on earth's surface in miles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\begin{align*}&#xA;369 \cdot \dfrac{3}{4 \pi} &amp;amp;= (3959+x)^3 - (3959)^3 \\[.5pc]&#xA;369 \cdot \dfrac{3}{4 \pi}+3959^3 &amp;amp;= (3959+x)^3 \\[.5pc]&#xA;\sqrt[3]{369 \cdot \dfrac{3}{4 \pi}+3959^3} &amp;amp;= 3959 + x \\[.5pc]&#xA;3959.0000018746 &amp;amp;\approx 3959 + x \\[.5pc]&#xA;.00000018746 &amp;amp;\approx x&#xA;\end{align*}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, the layer of CO&lt;sub&gt;2&lt;/sub&gt; on earth's surface would be $\approx 1.87 \cdot 10^{-6} \text{ mi}$ or $.1187 \text{ in}$ in thickness. Which is less than half the thickness of an iPhone 6.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;My Question&lt;/em&gt;&lt;/strong&gt;: This result seems incredibly small. Where did I go wrong? Or, is this reasonable. I have no intuition and would be interested in a second opinion!&lt;/p&gt;&#xA;" OwnerUserId="6141" LastEditorUserId="725" LastEditDate="2016-06-16T09:19:39.090" LastActivityDate="2018-12-30T18:33:22.683" Title="Take all the CO2 in the atmosphere and put it into a layer on the surface of earth, how thick would the layer be?" Tags="|atmosphere|atmosphere-modelling|homework|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8180" PostTypeId="1" CreationDate="2016-06-14T08:42:24.607" Score="4" ViewCount="386" Body="&lt;p&gt;Point counting is an extremely useful tool for determining the composition of a clastic sedimentary rock. It is also very useful in provenance studies to determine the sediment source of a sedimentary rock (see, for example, the classic paper by Dickenson and Suczek, 1979). The theory behind point counting is straight forward. For me, putting it into practice has been challenging because I cannot find the &quot;definitive guide to point counting&quot;. I know the general rule is 300-500 points per slide and that the step size should be 1.5 x grain size (although &lt;a href=&quot;http://ws2.petrog.com/point_counting.html&quot; rel=&quot;nofollow&quot;&gt;this&lt;/a&gt; company says otherwise).  But what is the maximum grain size one can analyse on thin section before the counting becomes statistically unrepresentative?&lt;/p&gt;&#xA;" OwnerUserId="6083" LastActivityDate="2016-06-15T20:18:36.343" Title="What is the maximum grain size of a sediment that can be point counted using a standard thin section?" Tags="|geology|sedimentology|petrology|petrography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8181" PostTypeId="1" CreationDate="2016-06-13T17:20:42.463" Score="7" ViewCount="300" Body="&lt;p&gt;What would the sky color be for the Proterozoic Earth during the &amp;quot;Boring Billion&amp;quot; years(1.8 Ga-0.8 Ga) with a Canfield (Euxinic) ocean and a high atmospheric concentration of colorless hydrogen sulfide and very low atmospheric oxygen? Would it really be a light green as proposed by Professor Peter Ward in his book &lt;em&gt;Under a Green Sky&lt;/em&gt;, which he states but did not provide a rationale?&lt;/p&gt;&#xA;" OwnerDisplayName="Nelson Isada" LastEditorUserId="2470" LastEditDate="2023-05-09T01:18:11.563" LastActivityDate="2023-05-10T05:56:55.520" Title="Sky color of a proterozoic earth with a Canfield ocean" Tags="|atmosphere|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="8182" PostTypeId="2" ParentId="8178" CreationDate="2016-06-14T14:34:42.213" Score="7" Body="&lt;p&gt;Temperature is certainly a factor, but it's not that simple. Actually a lot of water &lt;em&gt;does&lt;/em&gt; sink into the Earth, mostly as meteoric circulation, but also as deposition of hydrous minerals, trapped pore water, and carried down towards the lower crust in the 'wet sediments' of subduction zones. The latter is the ultimate source of most volcanic water vapor.&#xA;Of course, pressure increases with depth, and this pressure tends to close up any pores, fractures or fault cavities. So the deeper the water sinks, the less scope there is for water circulation. Also, the deeper the rock, the hotter it gets so it is likely that the tiny amount of water in deep circulation will be absorbed by water-rock interaction to yield a hydrous assemblage of minerals. If the water is heated to water vapour then it is easy for this vapour to move laterally, or upwards (higher porosity), but not so much downwards (little or no porosity). Finally there is the density factor. Water is less dense than rock so it tends to find its own level: gas at the top, then hydrocarbons (if any) further down, then freshwater, then saline water, then no fluid at all because there is no linked porosity for the fluid to occupy.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-14T14:34:42.213" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8183" PostTypeId="2" ParentId="8177" CreationDate="2016-06-14T14:47:47.087" Score="5" Body="&lt;p&gt;NVZ is correct. Get a palaeo-geographical atlas and see how the the distribution of the continents has changed over time. There is much more ocean than land, and it has ever been so, but there is no particular pattern to the way the continents have drifted. It's not quite random because the heat distribution in the mantle isn't random, but given the conveyor belt system of plate tectonics there will always be a tendency for crustal plates to clump together before breaking up and then clumping together somewhere else. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-14T14:47:47.087" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8186" PostTypeId="2" ParentId="8177" CreationDate="2016-06-14T20:45:41.973" Score="2" Body="&lt;p&gt;You are correct that it seems that the Pacific is covering half of the Earth and the landmass cover the other half. But in Earth's history there were several times that it was even more extreme. From about 250 to 200 million years ago, all continents were concentrated even more in a supercontinent called Pangaea:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Rbkiw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Rbkiw.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;sup&gt;source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Pangaea_continents.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://commons.wikimedia.org/wiki/File:Pangaea_continents.png&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This continent would cover anything from a quarter to a third of the Earth's surface, the rest being a massive ocean called Panthalassa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason this happens is plate tectonics: lithospheric plates, which carry the continents, move and drift slowly. Here's a nice simplified animation of how this works:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=I_q3sAcuzIY&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=I_q3sAcuzIY&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another animation showing how this changed during Earth's (recent) history:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=uGcDed4xVD4&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=uGcDed4xVD4&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for now,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is this coïncidence or plays there something else?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is not a coincidence. The oceanic spreading centres that appear in the above video spread at different rates. The one at the Pacific does so relatively fast, and a large mass of oceanic lithosphere is being constantly produced in there. Consequently, the Pacific is quite large. It is slowly getting smaller though. Today's Pacific is the remnant of the old Panthalassa which used to be much larger. The Pacific is surrounded by subduction zones that recycle the oceanic lithosphere back into the mantle, resulting in the infamous Ring of Fire around the Pacific ocean.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-06-14T20:45:41.973" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8187" PostTypeId="2" ParentId="8178" CreationDate="2016-06-14T22:35:45.207" Score="10" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;So what prevents that happening on earth?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Not much. Quite a lot of water is recycled into the Earth's crust and mantle.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;So the only thing that prevents the water from sinking in is the temperature, right?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;That's part of the story. For our discussion, water can exist in two forms:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Molecular water as H&lt;sub&gt;2&lt;/sub&gt;O, being in one of several phases (liquid water, solid ice, supercritical fluid, water vapour),&lt;/li&gt;&#xA;&lt;li&gt;Structural water in solid minerals. For example, in clay minerals aka mud. Kaolinite is one of the minerals that make up mud (or dust) and has the formula Al&lt;sub&gt;2&lt;/sub&gt;Si&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt;(OH)&lt;sub&gt;4&lt;/sub&gt;. See that (OH)&lt;sub&gt;4&lt;/sub&gt; in there? That's basically water. Even if you take a pile of mud, dry it at 110 °C in an oven until it's completely dry, the water is still going to be in there.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Molecular water can react with rocks and minerals to form hydrous minerals and get trapped as structural water (similar to adding water to Portland cement in the making of concrete), and hydrous minerals can be heated enough to release this water (usually requiring hundreds of degrees).&lt;/p&gt;&#xA;&lt;p&gt;Let's look at some examples of how this thing might work.&lt;/p&gt;&#xA;&lt;p&gt;Oceans have mid ocean ridges, where the oceanic lithosphere is being formed. This area has very shallow magma chambers so the rock is extremely hot. Water that percolates down through cracks gets heated to a large degree, lowering the density and increasing the buoyancy of the water. This water then goes back up through hydrothermal vents on the seafloor. Here's a spectacular video of some of those things:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=rTR6gGDWcJk&quot; rel=&quot;noreferrer&quot;&gt;https://www.youtube.com/watch?v=rTR6gGDWcJk&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;When the water goes down, not all of it goes back up. It also reacts with the rock, forming hydrous minerals. For example, anorthite (CaAl&lt;sub&gt;2&lt;/sub&gt;Si&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;8&lt;/sub&gt;), a common mineral in basalts, is hydrated to epidote-clinozoisite: Ca&lt;sub&gt;2&lt;/sub&gt;Al&lt;sub&gt;3&lt;/sub&gt;Si&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;12&lt;/sub&gt;(OH). In some occasions, oceanic crust can be uplifted and is then exposed. One example is Cyprus, where you can see features like this:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Zv8aA.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Zv8aA.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;What you're looking at is basically anhydrous rocks (the white stuff) replaced by hydrous minerals (the brown stuff) due to upwelling hot water in the oceanic crust. Above it, now gone, was a hydrothermal vent like the ones in the video.&lt;/p&gt;&#xA;&lt;p&gt;On land, water does sink deep down as well. As Gordon mentioned in his answer, water is common in oil reservoirs, but it's just about anywhere else. It is particularly rich in sedimentary rocks, that still have some amount of the liquid water that existed during sediment deposition (river, lagoon, lake, etc).&lt;/p&gt;&#xA;&lt;p&gt;A good property of water in subsurface conditions, is that at higher temperature and pressure it can dissolve and leach metals from rock. This provides a way to move metals around, eventually depositing these metals in localised locations so we can exploit them. Lead, zinc and gold are examples of metals that can be concentrated by circulating water.&lt;/p&gt;&#xA;&lt;p&gt;Water can also go deep down into the mantle in subduction zones. Water trapped in pore spaces and hydrous minerals can sink hundreds of kilometres down into the Earth. Eventually, the temperature becomes too hot to sustain the water in there and the rock devolatilise: they lose the water (which is a supercritical fluid at this stage). This water is then incorporated into magmas, and erupted in volcanoes. In many volcanoes, especially in arc volcanoes (such as the ones around the Pacific ocean), a major component of &amp;quot;volcanic gas&amp;quot; is actually water vapour.&lt;/p&gt;&#xA;&lt;p&gt;To sum it up, water goes down, water goes up. It's all one huge happy cycle.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-06-14T22:35:45.207" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8188" PostTypeId="1" AcceptedAnswerId="8190" CreationDate="2016-06-15T01:41:38.103" Score="6" ViewCount="5030" Body="&lt;p&gt;There are four different categories of clouds. High clouds, medium altitude clouds, lower clouds, and vertical tall clouds. They are broken down into ten genuses of clouds: Cirrus, Cirrocumulus, Cirrostratus, Altocumulus, Altostratus, Stratocumulus, Cumulus, Stratus, Cumulonimbus, and Nimbostratus. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally there are 14 species, 9 types, and 9 additional phenomenons like Virga or Mammatus, but these are not really important in my question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I find it troublesome to distinguish the Altocumulus, Stratocumulus and Cumulus clouds from each other. The hardest to distinguish in my opinion are the Stratocumulus and Altocumulus clouds. Even though I know, Ac are higher clouds than Sc, it is most of the time hard for me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone point out any differences that would help me distinguish these genuses of clouds?&lt;/p&gt;&#xA;" OwnerUserId="6148" LastActivityDate="2020-03-09T10:41:24.100" Title="How to distinguish between Altocumulus, Stratocumulus and Cumulus clouds?" Tags="|atmosphere|clouds|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8189" PostTypeId="2" ParentId="8179" CreationDate="2016-06-15T02:42:38.300" Score="6" Body="&lt;p&gt;Ok, based on the comments above, this is where I am at... &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;earth's radius is $6371 \text{ km}$&lt;/li&gt;&#xA;&lt;li&gt;earth is a sphere&lt;/li&gt;&#xA;&lt;li&gt;There is approximately $3 \cdot 10^{15}$ kg of CO2 in earth's atmosphere&lt;/li&gt;&#xA;&lt;li&gt;The density of CO2 at 1atm is $\dfrac{1.977 \text{ kg}}{\text{ m}^3}$&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;So, first, with assumption (3 and 4) we can compute the volume of CO2 in the atmosphere to be $\approx 1.52 \cdot 10^{15} \text{ m}^3$ or $1.52 \cdot 10^6 \text{ km}^3$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, now we can find the thickness of the layer by solving the equation&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\begin{align*}&#xA;1.52 \cdot 10^6 &amp;amp;= \dfrac{4 \pi \cdot (6371 + x)^3}{3} - \dfrac{4 \pi (6371)^3}{3} \\&#xA;\end{align*}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where $x$ is the thickness of the layer of CO2 on earth's surface in km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\begin{align*}&#xA;1.52 \cdot 10^6 \text{ km}^3 &amp;amp;= \dfrac{4 \pi \cdot (6371 + x)^3}{3} - \dfrac{4 \pi (6371)^3}{3} \\[.5pc]&#xA;\dfrac{3}{4\pi} \cdot 1.52 \cdot 10^6 \text{ km}^3 &amp;amp;= (6371+x)^3 - 6371^3 \\&#xA;\dfrac{1.14}{\pi} \cdot 10^6 \text{ km}^3&amp;amp;= (6371+x)^3 - 6371^3 \\&#xA;3.63 \cdot 10^5 +6371^3 \text{ km}^3 &amp;amp;= (6371 + x)^3 \\&#xA;\sqrt[3]{3.63 \cdot 10^5 +6371^3 \text{ km}^3} &amp;amp;= 6371 + x \\&#xA;6371.0029811 \text{ km} &amp;amp;\approx 6371 + x \\&#xA;.0029811 \text{ km} &amp;amp;\approx x&#xA;\end{align*}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, the layer of CO2 on earth's surface would be 2.98 meters thick...&lt;/p&gt;&#xA;" OwnerUserId="6141" LastEditorUserId="6141" LastEditDate="2016-06-24T06:42:06.493" LastActivityDate="2016-06-24T06:42:06.493" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8190" PostTypeId="2" ParentId="8188" CreationDate="2016-06-15T04:38:44.710" Score="5" Body="&lt;p&gt;You are not alone. Allmost everyone has difficulty differentiating Ac from Sc because, apart from the obvious low clouds, you can't accurately discern a cloud's height purely from looking at it. For that you need a 'ceilometer', which is a vertical beam of light reflected off the cloud-base. Not many met sites have this. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2016-06-15T08:47:14.333" LastActivityDate="2016-06-15T08:47:14.333" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8191" PostTypeId="1" AcceptedAnswerId="8192" CreationDate="2016-06-15T14:16:47.197" Score="8" ViewCount="445" Body="&lt;p&gt;Today's &lt;a href=&quot;https://www.youtube.com/watch?v=gLNmtUEvI5A&quot;&gt;SpaceX webcast&lt;/a&gt; featured an interesting quote, that Cape Canaveral is the lightning capital of the US. Is that really the case? If not, how does it compare in lightning strikes to other areas in the US?&lt;/p&gt;&#xA;" OwnerUserId="6151" OwnerDisplayName="PearsonArtPhoto" LastEditorUserId="6151" LastEditDate="2016-06-15T18:19:27.677" LastActivityDate="2019-06-29T20:15:41.937" Title="Is Cape Canaveral really the lightning capital of the US?" Tags="|lightning|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8192" PostTypeId="2" ParentId="8191" CreationDate="2016-06-15T14:25:39.973" Score="6" Body="&lt;p&gt;It's pretty likely. Florida has the highest lightning strikes of anywhere in the US, as can by seen by &lt;a href=&quot;http://lightningsafety.com/nlsi_info/lightningmaps/US_FD_Lightning.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this map from lightningsafety.com&lt;/a&gt; This is the area near Florida, with the highest levels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's hard to see, but the highest density is actually just to the west of the Cape, but it's not too far of a stretch to say it's the lightning capital of the US.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UTVc9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UTVc9.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6151" OwnerDisplayName="PearsonArtPhoto" LastActivityDate="2016-06-15T14:25:39.973" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8193" PostTypeId="2" ParentId="8180" CreationDate="2016-06-15T20:18:36.343" Score="4" Body="&lt;p&gt;you might have guessed: There is no such an easy answer as a precise, always valid maximum grain size.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Point counting is an upscaling technique. It works when the sample area you inspect is &gt;= to the so-called representative elementary area (REA) of the rock facies. The larger your grains, the larger needs the REA to be. Same holds true for increasing heterogeniety and increasing number of mineral phases.&#xA;So check if your point count analysis is changing when you increase the inspection area. Once the analysis comes to a stable ratio of analysed items, you found the REA of the rock facies. This REA is a material property and not depending on the step size you choosed (as long as you make sure to obey the law of large numbers for each area).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-&gt; look for &quot;REA&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Best,&#xA;Ben&lt;/p&gt;&#xA;" OwnerUserId="6152" LastActivityDate="2016-06-15T20:18:36.343" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8198" PostTypeId="1" AcceptedAnswerId="8204" CreationDate="2016-06-17T02:06:20.277" Score="14" ViewCount="432" Body="&lt;p&gt;Satellite remote sensing data is a powerful tool for researching the spatial distribution and temporal variation of atmospheric species.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Aura&lt;/strong&gt; is one satellite owing to NASA which meaning atmosphere in Latin literally.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;OMI&lt;/strong&gt; which means Ozone Monitoring Instrument has the global observation data for $\ce{O3}$, $\ce{NO2}$, $\ce{BrO}$ etc.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Getting the $\ce{NO2}$ monthly mean data from &lt;a href=&quot;http://www.temis.nl/airpollution/no2col/no2regioomimonth_v2.php&quot; rel=&quot;noreferrer&quot;&gt;TEMIS&lt;/a&gt;, the ESRI grid format file was plotted by me showing here:   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1CtFh.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1CtFh.png&quot; alt=&quot;A satellite image&quot;&gt;&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have noticed that the figure are covered by discrete silk braid (in my plot, they are plotted in green color liking raining top-&gt;down) like this:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RppOR.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RppOR.png&quot; alt=&quot;An excerpt from the same image&quot;&gt;&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;IMHO, these braid must be not related to the anthropogenic emission but something related to the satellite orbit. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For quantify research of certain grid box, these braid would influence the finite column concentration.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Besides, from NASA Giovanni online visualization tools, the figure below is also the $\ce{NO2}$ tropospheric column in the same area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kVqw6.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kVqw6.png&quot; alt=&quot;More satellite data&quot;&gt;&lt;/a&gt;    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are no silk braid like my figure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, my question is here: &lt;strong&gt;How to remove these abnormal value for more precise data&lt;/strong&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That would be nice if anyone familiar with this area give me some advice.       &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Update&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Thanks for @deneil's attention. I presented two data source here for distinguishing.      &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;TEMIS data was called &lt;em&gt;Dutch OMI NO&lt;sub&gt;2&lt;/sub&gt; (DOMINO) data product v2.0&lt;/em&gt;.&lt;br&gt;&#xA;In its official manual &lt;a href=&quot;http://www.temis.nl/docs/OMI_NO2_HE5_2.0_2011.pdf&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;, it said, I quoted:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;DOMINO = Level 2 product&lt;/strong&gt;&lt;br&gt;&#xA;The DOMINO data contains geolocated column integrated $\ce{NO2}$ concentrations, or&lt;br&gt;&#xA;$\ce{NO2}$ columns (in units of molecules/cm2). DOMINO data constitute a pure Level 2 product, i.e.       &lt;/li&gt;&#xA;&lt;li&gt;it provides geophysical information for each and every ground pixel observed by the instrument, without the additional binning, averaging or gridding typically applied for Level 3 data.      &lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The Giovanni visualization tool use OMI/Aura $\ce{NO2}$ Cloud-Screened Total and Tropospheric Column Daily L3 Global 0.25deg Lat/Lon Grid which means it's level 3 data.    &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I think the difference sitting there. But I have also tried OMI $\ce{NO2}$ level2 data from NASA (OMI has two independent data source in Dutch and NASA), it has 15 candidate scenes which was plotted different from the TEMIS DUMNO2 data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is an example. The figure below plot the level 2 data in tilted grid due to the satellite orbits. Level 3 data must resample the tilted grid data into regular grid network.  So, I think my first figure shows the right result as level 2 data's character. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mn83h.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mn83h.png&quot; alt=&quot;A satellite image&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Updated II&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;There are three different source for tropospheric $\ce{NO2}$ column. It seems that Berkely's dataset is the best choice.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/o9bm7.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/o9bm7.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="725" LastEditDate="2017-05-06T04:31:45.940" LastActivityDate="2017-05-06T04:31:45.940" Title="How to remove 'silk braid' noise in satellite data?" Tags="|atmosphere|remote-sensing|air-pollution|satellites|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8199" PostTypeId="2" ParentId="3127" CreationDate="2016-06-17T03:17:05.560" Score="1" Body="&lt;p&gt;The long term influences upon the Earth's atmosphere are additions, subtractions and internal variations. The additions consist of gravitational attraction of passing gas molecules from space, which is insignificant, and outgassing from the solid Earth. The latter is 'new' helium from radioactive processes, and volcanic gasses which are mostly long-term recycled from the surface via subduction zones. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Subtractions involve loss of gass molecules by thermal heating in the very tenuous outer regions of the atmosphere. Some of the lighter gasses, mainly hydrogen and helium, attain energies which allow them to exceed the escape velocities. This is why our atmosphere hasn't built up much higher concentrations of the light elements over time. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Internal variations are such geochemical and biological feedback processes as greenhouse gases influencing the temperature, and hence evaporation / ice accumulation, etc. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;None of the above have anything to do with pressure fluctuations caused by the moons orbit. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-17T03:17:05.560" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8200" PostTypeId="1" AcceptedAnswerId="8225" CreationDate="2016-06-17T04:08:07.427" Score="3" ViewCount="87" Body="&lt;p&gt;Water molecules, as many people know, are polarized, and so water molecules tend to have an attractive force between them.  But how would the waves in water behave if this attraction no longer was present, but everything else was the same?&lt;/p&gt;&#xA;" OwnerUserId="4942" LastActivityDate="2016-06-20T21:58:52.837" Title="How would waves (in a fluid) behave without intermolecular attraction?" Tags="|ocean|water|waves|hypothetical|wave-modeling|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8201" PostTypeId="1" CreationDate="2016-06-17T12:34:21.970" Score="1" ViewCount="125" Body="&lt;p&gt;I have a dataset which contains daily NO2 and ozone levels of the 50 largest cities in Spain for one year (so 50 x 365 observations). The data are retrieved from &lt;a href=&quot;http://www.eea.europa.eu/data-and-maps/data/airbase-the-european-air-quality-database-7&quot; rel=&quot;nofollow&quot;&gt;http://www.eea.europa.eu/data-and-maps/data/airbase-the-european-air-quality-database-7&lt;/a&gt;. When regressing ozone on NO2, I find a significantly negative coefficient for contemporaneous NO2 (-0.35, standard error 0.027), the first lag (-0.05, standard error 0.014), insignificant coefficients on NO2-levels on the second and third lag (-0.0014 and 0.014 respectively), and a positive coefficient on the level of NO2 five days ago (0.50, standard error 0.013).&#xA;I am also controlling for time-invariant local characteristics (fixed effects) and (lagged) weather conditions (temperature, sunshine, cloud cover, precipitation, wind).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm an economist so I don't know much about these things. I guess this could be explained by the complex mechanics of ozone formation? It would be great if you have some reference or idea why such a relation can be observed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt; Added some more hopefully useful details.&lt;/p&gt;&#xA;" OwnerUserId="6160" LastEditorUserId="6160" LastEditDate="2016-06-21T13:32:50.613" LastActivityDate="2016-06-21T13:32:50.613" Title="Ground level ozone formation and NO2 dependence over time" Tags="|ozone|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8202" PostTypeId="2" ParentId="8201" CreationDate="2016-06-17T15:41:14.633" Score="1" Body="&lt;p&gt;I am unsure of the details of your dataset (length, temporal resolution, location, etc.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For he one day time lag, it is easily explained. NO2 is consumed to produce ozone, so as NO2 decreases, O3 increases. However, for that reaction to occur, you need UV radiation. So as NO2 decreases, ozone increases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the fourth day lag, I would be a bit suspicious to take meaning out of this, due to my lack of knowledge on details of the dataset. For example, it could've been cloudy preventing the production of NO2 and ozone, but letting NO build up, such that when the sky cleared, the NO was allowed to photlyze, but that is just a guess.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2016-06-17T15:41:14.633" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8204" PostTypeId="2" ParentId="8198" CreationDate="2016-06-18T00:10:20.090" Score="7" Body="&lt;p&gt;You ask, &lt;em&gt;How to remove these abnormal value for more precise data?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The short answer is that you might be able to make your data look more representative of the natural 'truth', but you will probably have to pay for this with some precision. The problem is that the measurement itself is imperfect: this looks like an artifact of the data collection method. The general name for unwanted energy that interferes with a signal you are interested in is &lt;a href=&quot;https://en.wikipedia.org/wiki/Noise_(signal_processing)&quot; rel=&quot;noreferrer&quot;&gt;noise&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In your case, there is some random noise, and there is this coherent (i.e. spatially organized) noise. It is likely impossible to substantially attack either type of noise without touching the signal. In other words, you will probably have to pay for the noise reduction with some loss of precision. This may be a trade-off you are willing to make.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Reducing noise&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;There are many, many ways to &lt;a href=&quot;https://en.wikipedia.org/wiki/Noise_reduction&quot; rel=&quot;noreferrer&quot;&gt;reduce noise&lt;/a&gt; in data. A very common way to reduce random noise is to apply a &lt;a href=&quot;https://en.wikipedia.org/wiki/Smoothing&quot; rel=&quot;noreferrer&quot;&gt;smoothing filter&lt;/a&gt; such as a simple mean in some small, moving window (often expressed as a convolution operation). The problem with this is that it just mixes the noise into the image.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can also think of a smoothing high-cut filter in the spatial frequency (aka &lt;a href=&quot;https://en.wikipedia.org/wiki/Wavenumber&quot; rel=&quot;noreferrer&quot;&gt;wavenumber&lt;/a&gt;) domain. A common approach to removing the sort of spatially organized noise you have is to use a 'notch' (narrow) cut filter in this domain, which has the effect of removing noise with that spatial frequency. In other words, you can remove stripes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Filters that remove stripes can be found in various image processing software, or could be implemented with various scientific computing languages (e.g. MATLAB's &lt;a href=&quot;http://www.mathworks.com/products/image/&quot; rel=&quot;noreferrer&quot;&gt;Image Processing Toolbox&lt;/a&gt; or &lt;a href=&quot;http://scikit-image.org/&quot; rel=&quot;noreferrer&quot;&gt;scikit-image&lt;/a&gt; for Python). Here are some options:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://imagej.nih.gov/ij/docs/guide/146-29.html#toc-Subsection-29.10&quot; rel=&quot;noreferrer&quot;&gt;FFT in ImageJ/FIJI&lt;/a&gt; — I would start here, unless you're already into MATLAB or Python.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://docs.gimp.org/en/plug-in-destripe.html&quot; rel=&quot;noreferrer&quot;&gt;Destripe in GIMP&lt;/a&gt; — another good option.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://isis.astrogeology.usgs.gov/IsisWorkshop/index.php/Removing_Striping_Noise_from_Image_Data&quot; rel=&quot;noreferrer&quot;&gt;Destriping in ISIS&lt;/a&gt; — an image processing package from USGS.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2016-06-18T00:10:20.090" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8205" PostTypeId="2" ParentId="8130" CreationDate="2016-06-18T00:27:58.657" Score="4" Body="&lt;p&gt;I will just talk about an already formed tropical cyclone. Converging winds spiral in (counterclockwise in northern hemisphere) over the warm ocean waters towards the central low pressure area of the eye.&lt;/p&gt;&#xA;&lt;p&gt;At the eye they spiral upwards, taking the warm, moist ocean air high into the atmosphere. As it reaches cooler elevation, the air releases its latent heat, adding more energy to the storm.&lt;/p&gt;&#xA;&lt;p&gt;So you have a tremendous volume of air converging from 360 degrees around the hundreds of miles of the storm, all converging on the eye and spiraling up with an intense updraft, creating a very low pressure near the surface in the eye/core.&lt;/p&gt;&#xA;&lt;p&gt;High above the eye wall this upflow begins to spread out. This permits cool dry air above the eye to sink down into the central core of the eye (that is why the eye is often clear and cloud free).&lt;/p&gt;&#xA;&lt;p&gt;So why is the hurricane core/eye low pressure when there is cool dry air subsiding down into the core/eye?&lt;/p&gt;&#xA;&lt;p&gt;Soundings taken within the eye show a low-level layer (at surface) that is relatively moist with an inversion above, i.e., it appears that the sinking cool dry air (which warms somewhat as it is compressed in descent) never reaches the ocean surface, but only reaches within 1 - 3 km (1 - 2 mi) of the surface. See, among other sources, &lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/A11.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.aoml.noaa.gov/hrd/tcfaq/A11.html&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Sept. 9, 2023 edit:&#xA;I happened across a superb meteorology textbook available under CC license (you may share it freely for non-commercial use):&lt;/p&gt;&#xA;&lt;p&gt;Stull, R., 2017: &amp;quot;&lt;a href=&quot;https://www.eoas.ubc.ca/books/Practical_Meteorology/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Practical Meteorology: An Algebra-based Survey of Atmospheric Science&lt;/a&gt;&amp;quot; -version 1.02b.  Univ. of British Columbia.  940 pages.  isbn 978-0-88865-283-6&lt;/p&gt;&#xA;&lt;p&gt;Stull provides comprehensive, understandable (if you can read college-level material) coverage of tropical cyclones (as one subject of meteorology), and definition and discussion of related concepts throughout this textbook. To try to cover the contingency, that the link becomes inactive, I uploaded a copy of the text in pdf to &lt;a href=&quot;https://archive.org/details/practical-meteorology-textbook&quot; rel=&quot;nofollow noreferrer&quot;&gt;Practical Meteorology at archive.org&lt;/a&gt;. Use the pdf button to obtain the copy.&lt;/p&gt;&#xA;&lt;p&gt;For a quick hint at the Stull treatment, I include a figure from his text showing the intake system of the tropical cyclone in schematic cross section. This nicely illustrates that the majority of the updraft air coming up the walls of the eye diverges at the top of the core, rather than subsiding down the core (see text):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BDQxT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BDQxT.png&quot; alt=&quot;Fig 16.26 Intake System Tropical Cyclone&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Also, a figure from Stull showing the difference in temperature within the hurricane core relative to surroundings:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/keCem.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/keCem.png&quot; alt=&quot;Fig 16.28 Core temperatures hurricane relative to surroundings&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;That perhaps makes it more sensible that the warmer core air cannot continue subsiding down to the near-sea surface low at base of the core, where the air is very moist, but at lower temperature (might consider this to be a high stopping on encounter with a low).&lt;/p&gt;&#xA;" OwnerUserId="6120" LastEditorUserId="6120" LastEditDate="2023-09-06T16:43:07.697" LastActivityDate="2023-09-06T16:43:07.697" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="8206" PostTypeId="2" ParentId="2232" CreationDate="2016-06-18T00:57:50.683" Score="3" Body="&lt;p&gt;What do mountains look like without precipitation? We have an excellent example here on Earth: in the Andes, between the latitudes of 17 and 30 degrees South. These mountains aren't granite, but they are a mix of igneous and meta-igneous rocks, which are similarly crystalline.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The eastern slopes of the mountains is moistened by water that evaporates in the Amazon Basin. The west side is the Atacama Desert. For example, the capital of Bolivia, La Paz, sits in the eastern foothills, and receives 500-600mm of rainfall per year. In contrast, the Chilean city of Arica - only 350km away - receives an average of 0.08mm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a Google Earth view of the Andes between Arica and La Paz with my pointer on the continental divide (which is not the highest point, as my line coincidentally runs over a summit in Bolivia).&#xA;&lt;a href=&quot;https://i.stack.imgur.com/TseCS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TseCS.jpg&quot; alt=&quot;Google Earth view of the Andes between Arica and La Paz&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can immediately zoom in on the effects of precipitation on the mountains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The highest summits: No precipitation means no glaciation&lt;/strong&gt;&#xA;Fig. 1 is a close-up of two high Andean peaks which appeared in the photo above: the gorgeous, volcanic 6310m Parinaquta on the eastern slopes [Fig. a left], and the rugged 6350m Illimani on the west [Fig. a right].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Illmani has been deeply glaciated, as have most high summits around the world. Its flanks are cut by U-shaped valleys. Its summit is surrounded by steep glacial headwalls. When those headwalls retreat, the summit will collapse. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Parinaquta, in contrast, has clearly never held much ice (though a little snow still clings to the summit - nowhere on Earth is entirely dry). The dominant texture on the mountain is not caused by glacial valleys, but by individual lava flows. The mountain has good radial symmetry, like volcanoes on Mars. It will continue to grow for a long time yet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cGili.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cGili.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Middle elevations: strangely straight channels&lt;/strong&gt;&#xA;Let's take a look at the dry side of the Andes at lower elevations. Fig. b shows a 30-km area located halfway between Parinaquta and Arica.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These channels are quite unusually straight. No quantitative work has been done on these channels to the best of my knowledge (at least in the English scientific literature; Chilean geologists may have done much more).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Morgan et al. (2014) assert that these channels are formed by mud-rich flows. These wet flows are few and far between. The majority of the sediment is moved by air. The wind in the area flows preferentially through the channels, but - unlike the mudflows, or normal rivers - it is driven less by downhill-gradients than by large-scale weather gradients in the area. The wind flows straight, and it straightens the channels. [Morgan et al. also suggest that, during particularly dry periods, the wind may leave channels in inverted relief].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Coastlines: dry climates don't erode much&lt;/strong&gt;&#xA;Your question does not directly mention coastlines, but the dry Arica coast does have one relevant feature: the river mouths do not have noticeable deltas. The volume of a delta is a rough proxy for the rate at which sediment is removed from the mountains upstream and carried out to the ocean, minus the rate at which the ocean carries sediment away from the shore. This proxy has limited value, as it is greatly affected by ocean dynamics, the drainage area of the river, and the presence of a subduction zone near the shore.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most wet coastlines with subduction zones (such as the coast of Papau New Guinea, Fig. c left) produce enough sediment to maintain estuaries, deltas, or little puffs of sand. In contrast, the rivers near Arica hardly change the shape of the Chilean coastline (Fig. c right).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can predict that a reduction in total precipitation on the Earth would drastically reduce the average erosion rate on land.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Global changes&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth, unlike Mars, has active tectonics. Our volcanoes will never grow to the height of Olympus Mons because the continental plates shift beneath them. Yet our mountains now are beset by river incision and by glaciation. Their lifetime is short - perhaps half a billion years, no more, and usually far less. Wind erosion is ~one hundredth the speed of glacial and fluvial erosion. On Dry Earth, a mountain range might survive to be nearly the same age as the planet. If tectonics were to carry on at their usual rate, mountains would soon cover much of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sedimentary rocks would be rarer, and made of baked dust rather than river cobbles or mud. Needles of salt might grow on the plains, if there was enough moisture for the air to carry them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I imagine Dry Earth as a towering desert, where the lowlands are walled in by the broken remnants of billion-year-old mountain chains, and the dust is made from dark volcanic rock.&lt;/p&gt;&#xA;" OwnerUserId="6163" LastActivityDate="2016-06-18T00:57:50.683" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8208" PostTypeId="2" ParentId="8198" CreationDate="2016-06-18T02:40:05.533" Score="5" Body="&lt;p&gt;Thanks for @Kwinkunks's answer. I have read this &lt;a href=&quot;http://www.atmos-meas-tech.net/4/1905/2011/amt-4-1905-2011.pdf&quot; rel=&quot;noreferrer&quot;&gt;paper&lt;/a&gt;. And this figure may explain something important.&lt;br&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/8K68c.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8K68c.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I have already done is plotting the original data like the first subplot.&lt;br&gt;&#xA;From &lt;strong&gt;Destriped -  v1.02&lt;/strong&gt;, the noise data can be shown clearly.     &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Adding another figure to indicate the big importance of induced noise.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Cya9e.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Cya9e.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Huge difference there!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, I'll learn some technology to deal with the destriped problem. I'm familiar with &lt;em&gt;Python&lt;/em&gt;. Anyone who has similar project experience could post your method here.&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="5214" LastEditDate="2016-06-19T02:56:29.433" LastActivityDate="2016-06-19T02:56:29.433" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8209" PostTypeId="1" CreationDate="2016-06-18T09:00:33.980" Score="0" ViewCount="127" Body="&lt;p&gt;My question is in the header. It would seem to be a major environmental benefit if toilets used saltwater in stead of drinkable fresh water, right? &lt;/p&gt;&#xA;" OwnerUserId="6166" LastActivityDate="2016-06-18T13:45:01.493" Title="Why don't toilets use saltwater?" Tags="|ocean|water|environmental-protection|" AnswerCount="1" CommentCount="4" ClosedDate="2016-06-18T14:53:10.710" ContentLicense="CC BY-SA 3.0" />
  <row Id="8210" PostTypeId="2" ParentId="8209" CreationDate="2016-06-18T13:45:01.493" Score="3" Body="&lt;p&gt;This question has tenuous links to Earth Sciences, but the answer is simply that, historically, freshwater has been used to flush toilets, and hence the sewage treatment plants have been developed to treat non-saline sewage. The water can be (and frequently is) recycled for domestic use, whilst sewage sludge can be used to enrich farmland. No such benefits accrue to flushing effluent with saline water. It is then pollution, whether it is disposed of on land or at sea. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In many estuaries and deltas around the world sewage sludge does end up in the sea where it accumulates as tidal mud flats with an unnaturally high lipid content. Give this sediment a few tens of millions of years of compression and maturation and it will doubtless yield oil shale. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-18T13:45:01.493" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8211" PostTypeId="1" AcceptedAnswerId="8212" CreationDate="2016-06-18T19:08:37.730" Score="7" ViewCount="21223" Body="&lt;p&gt;Is it possible to have rain without visible clouds?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as I know, clouds are liquid water and eventually the liquid water in them falls down, producing rain. Therefore one would expect clouds before rain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But is it theoretically possible to have rain when there aren't any visible clouds? Maybe if the concentration of liquid water in the air isn't too high it is possible.&lt;/p&gt;&#xA;" OwnerUserId="6168" LastActivityDate="2018-09-09T19:10:00.780" Title="Rain without clouds?" Tags="|meteorology|" AnswerCount="5" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8212" PostTypeId="2" ParentId="8211" CreationDate="2016-06-18T23:32:34.887" Score="4" Body="&lt;p&gt;I actually witnessed this in Ashland, OR several years ago. A strong winter storm had just passed when there was a sudden, brief downpour. When I looked up, there was not a cloud in the sky. What I believe happened is that the air was supersaturated with moisture when a brief breeze caused water to condensate around the few nuclei available. This seems to be confirmed by the second scenario in &lt;a href=&quot;http://chicagoweathercenter.com/blog/ask_tom_why_raining_without_clouds_overhead&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt; explanation: &lt;blockquote&gt;Consider the very rare situation in which still air is supersaturated with moisture (its relative humidity is above 100 percent) and clouds have not formed because condensation nuclei are practically nonexistent. Water vapor will quickly condense onto the few nuclei that are present and the droplets will rapidly grow into raindrops.&lt;/blockquote&gt;&lt;br&gt;This is the one and only time I have ever experienced this.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2016-06-18T23:32:34.887" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8213" PostTypeId="1" AcceptedAnswerId="8540" CreationDate="2016-06-19T01:02:30.393" Score="2" ViewCount="159" Body="&lt;p&gt;What is this pattern in the samples' surface called and how/why is it formed? I remember having seen a similar pattern in galvanized sheets. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Photos of metal samples from Wikimedia Commons (&lt;a href=&quot;https://commons.m.wikimedia.org/wiki/File:Vanadium-bar.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;https://commons.m.wikimedia.org/wiki/File:Aluminium_etched.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ubAnR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ubAnR.jpg&quot; alt=&quot;Vanadium bar&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/x3RXR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/x3RXR.jpg&quot; alt=&quot;Aluminum ingot&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6169" LastEditorUserId="2536" LastEditDate="2016-08-09T09:23:49.733" LastActivityDate="2016-08-09T10:04:20.217" Title="Voronoi-like pattern in metal samples" Tags="|geochemistry|mineralogy|crystallography|" AnswerCount="1" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8214" PostTypeId="1" AcceptedAnswerId="8216" CreationDate="2016-06-19T02:01:48.663" Score="5" ViewCount="1018" Body="&lt;p&gt;As I know, uranium is currently thought that it is mainly in the crust and not in the core or in the mantle. The reason for that it is a siderophile element which means it won't be solved in molten iron. Recent geoneutrino experiments seems to support this view, too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But, according to &lt;a href=&quot;https://chemistry.stackexchange.com/a/51798/7008&quot;&gt;this&lt;/a&gt; answer, the solubility of Uranium in the Earth Core is between 2ppm and 6ppm. This is not a really high value, but it is still much more as the mean proportion of the Uranium in the whole Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, first I think the general siderophility of Uranium is &lt;em&gt;not&lt;/em&gt; a reason to &lt;em&gt;not&lt;/em&gt; have a &lt;em&gt;lot&lt;/em&gt; of cubic kilometers of solved U in the outer core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second, what I think: trying to mix unmixable liquids they we will have separate phases of solutions in the order of their density. Also, trying to mix uranium and iron liquid, we will have&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;A phase of solution of uranium in iron (higher)&lt;/li&gt;&#xA;&lt;li&gt;Below that, a solution of iron in uranium.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;At least one of them will be also a saturated solution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, I don't see any reason, why wouldn't the Uranium concentrate in the outer crust. Or there is some mechanism out of these as well?&lt;/p&gt;&#xA;" OwnerUserId="6016" LastEditorUserId="-1" LastEditDate="2017-04-13T12:57:06.283" LastActivityDate="2016-06-19T07:58:38.653" Title="Why is uranium only in the crust, really?" Tags="|geochemistry|core|uranium|crust|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8215" PostTypeId="1" AcceptedAnswerId="8285" CreationDate="2016-06-19T07:05:13.520" Score="3" ViewCount="552" Body="&lt;p&gt;While hiking in the Ventana Wilderness in Big Sur, Calfornia, I kept trying to figure out one question: what is the source of the Big Sur river?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Big_Sur_River&quot; rel=&quot;nofollow&quot;&gt;Wikipedia reports its tributaries being the&lt;/a&gt; &lt;em&gt;Redwood Creek, Lion Creek, Logwood Creek, Terrace Creek, Ventana Creek, Post Creek, Pfeiffer-Redwood Creek, Juan Higuera Creek, and Pheneger Creek&lt;/em&gt;, but the source of the water is not described therein.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does any water from the Salinas Valley make it into the Santa Lucia mountain range, feeding into this river, or is it solely fed by rain fall? Does spring water play any role?&lt;/p&gt;&#xA;" OwnerUserId="6170" LastActivityDate="2016-11-27T00:16:51.670" Title="What is the source of the Big Sur river?" Tags="|hydrology|water|rivers|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8216" PostTypeId="2" ParentId="8214" CreationDate="2016-06-19T07:58:38.653" Score="6" Body="&lt;p&gt;&lt;em&gt;(tl;dr below)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, a correction. Siderophile elements are &quot;iron-loving&quot; elements, those that go in the core with the Fe-Ni liquid. Uranium is &lt;em&gt;lithophile&lt;/em&gt;, or &quot;rock-loving&quot;. It partitions to silicate rocky material (i.e. mantle and crust) relative to the core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;But, according to &lt;a href=&quot;https://chemistry.stackexchange.com/a/51798/8083&quot;&gt;this&lt;/a&gt; answer, the solubility of Uranium in the Earth&#xA;  Core is between 2ppm and 6ppm.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You have to understand where this is coming from. That answer is based on &lt;a href=&quot;https://arxiv.org/ftp/astro-ph/papers/0606/0606614.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; paper, which experimentally measured how much U is in the Fe phase, coexisting with a silicate phase of peridotite composition (which is an approximation of the mantle composition). If you look at their Table 3 (page 14) and Figure 8 (page 17) you can see that the $D_\rm{U}$ values range from almost 0 to around 0.03. This value mean the ratio of U in the metal phase relative to the silicate phase. So even in the most extreme case, you're going to have 30 times more U in the mantle than in the core. And in their experimental setup they used wt % amounts of U in the starting material, much much more than exists in the Earth, so you eventually get a considerable amount in the Fe-metal phase. This does not mean that this is the amount that is present there now, inside the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The truth is, we do not know how much U is there in the core. And this research papers shows that whatever amount there is, there will be more in the mantle. There will be even more in the crust, because U is an incompatible element in partial melting of the mantle. See this Q&amp;amp;A for more information about that:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/2950/725&quot;&gt;What are the high field strength and large ion lithophile (HFS or HFSE &amp;amp; LIL or LILE) elements?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also related, also read the comments:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/4798/725&quot;&gt;What percent of the Earth&amp;#39;s core is uranium?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Second, what I think: trying to mix unmixable liquids they we will&#xA;  have separate phases of solutions in the order of their density...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You have to differentiate solubility from partitioning. Solubility is how much of x (let's say U) you can put in y (let's say Fe) before you saturate a separate phase instead of one. Partitioning is when you have two phases x and y (let's say Fe-liquid and silicate), how much a third component z (let's say U) will dissolve in each. The paper linked to before was discussing partitioning. In terms of solubility, there is a complete solution of liquid U and Fe when the temperature is high enough (such as in the Earth's core). Even if there's not, a ppm amount of U in liquid Fe is &lt;em&gt;not&lt;/em&gt; enough to saturate a separate liquid U phase, so density doesn't matter. If it's all one phase, density plays no role. If you have a solution of NaCl and KCl in water, it's all homogeneous. The K doesn't sink because it's denser.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;tl;dr&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We do not know how much U is in the core. We do know that whatever amount of U goes in the core, more U will be in the silicate mantle. When you melt the mantle to produce magmas that form the crust, it concentrates U even more, and depletes the mantle of U.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:57:06.283" LastActivityDate="2016-06-19T07:58:38.653" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8217" PostTypeId="1" CreationDate="2016-06-19T13:12:43.413" Score="4" ViewCount="249" Body="&lt;p&gt;I'd like to ask if it's possible to output slope parameter and shape parameter of cloud hydrometeors in WRF?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm calculating cloud effective radius and I'm using the formula found in Morrison scheme which involves slope and shape parameters. There are calculations for these parameters as well in the scheme, however, I don't think I should be using that calculations to derive these parameters as I think that calculation is done during the &quot;process&quot; aka when the model is running which gives the final values of the parameters. So if I use the calculation again, it will change the outputted values, if you get what I mean?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd be happy to re-explain it again if it's not clear. I'm only just starting to get into radiative transfer calculation so my knowledge is still low in this area, therefore I very much appreciate your input/replies.&lt;/p&gt;&#xA;" OwnerUserId="3063" LastEditorUserId="192" LastEditDate="2016-06-19T13:52:26.953" LastActivityDate="2016-06-19T13:52:26.953" Title="How to output slope parameter and shape parameter in WRF?" Tags="|models|clouds|wrf|radiative-transfer|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8220" PostTypeId="1" CreationDate="2016-06-20T07:38:06.920" Score="0" ViewCount="2963" Body="&lt;p&gt;I've read that the pressure and temperature are different - how different are they, and does that affect the atmosphere's composition?&lt;/p&gt;&#xA;" OwnerUserId="6175" LastActivityDate="2019-04-03T23:20:31.263" Title="What are the composition and pressure of the exosphere?" Tags="|atmosphere|upper-atmosphere|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8221" PostTypeId="1" CreationDate="2016-06-20T09:39:42.527" Score="3" ViewCount="1696" Body="&lt;p&gt;Many of us are familiar with an exaggerated picture of the Moon's effect on Earth's tides:&lt;a href=&quot;https://i.stack.imgur.com/WPbGj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WPbGj.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Since the Earth is not uniformly covered with water, however, I imagine that the tidal effect will depend on which part of the Earth is facing the Moon (for simplicity, ignore the Sun's contribution).  I'm sure that the tidal effect still affects the Earth's landmasses, but I'm guessing that it would be to a lesser degree (i.e.: the landmasses would bulge out less than the oceans in the image above).  Now, by conservation of angular momentum, if the landmasses bulge out less, the Earth should rotate more quickly, hence this question's title.&lt;/p&gt;&#xA;&lt;p&gt;How does the tidal effect of the Moon's gravity affect the Earth's landmasses differently from its oceans?  And how big is this difference?&lt;/p&gt;&#xA;" OwnerUserId="4942" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-07-23T11:15:44.610" Title="How much do tides affect earth's rotational velocity?" Tags="|earth-rotation|moon|tides|gravity|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8222" PostTypeId="1" CreationDate="2016-06-20T20:27:26.223" Score="9" ViewCount="18543" Body="&lt;p&gt;Regardless the latitude and centrifugial 'force' is the gravity on mountains higher or lower than at sealevel? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gravity is depending on the radius to the centre and the mass. Now if you are on a mountain you are further from centre but it looks like you have more mass under you. Probably the differences would be tiny but is it likely that on mountains the gravity is higher or lower than at see level? As far as I could see till now where there are mountains the gravity is lower, but are there mountains where the gravity is higher?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="534" LastEditDate="2016-06-21T01:01:42.897" LastActivityDate="2021-01-17T01:11:00.720" Title="Does a mountain top have higher gravity than a nearby sea-level surface?" Tags="|geophysics|" AnswerCount="7" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8223" PostTypeId="2" ParentId="8222" CreationDate="2016-06-20T20:37:53.027" Score="0" Body="&lt;p&gt;Gravity is strictly a function of mass, distance, and gravitational constants.  The higher the mountain, the less effect gravity will have.  The amount is relatively trivial, but can be computed and measured as a distance from the center of gravity.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As compared to sea level, yes, their are mountain tops with gravity effects trivially higher, mountains with peaks below sea level.  There are entire mountain ranges under the oceans.&lt;/p&gt;&#xA;" OwnerUserId="6178" LastActivityDate="2016-06-20T20:37:53.027" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8224" PostTypeId="2" ParentId="8150" CreationDate="2016-06-20T20:58:33.050" Score="1" Body="&lt;p&gt;Atmospheric ozone is regularly produced by solar radiation energizing O(2) to split it and recombine it into O3.  Similarly, lightning also produces ozone at both low altitudes and higher in the atmosphere to recharge this layer.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Typical human produced ozone is a straight pollutant and does not recharge the &quot;ozone layer&quot;.&lt;/p&gt;&#xA;" OwnerUserId="6178" LastActivityDate="2016-06-20T20:58:33.050" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8225" PostTypeId="2" ParentId="8200" CreationDate="2016-06-20T21:58:52.837" Score="1" Body="&lt;p&gt;There are different factors that make water a media for waves. For transversal waves the viscosity and cohesion of molecules are essential. Even if the water is assumed not to evaporate. Try to imagine pushing a boat forward in a liquid with low viscosity. The propeller will just easily skid without generating any wave or traction.&lt;br&gt;&#xA;However for P waves a liquid with low or no viscosity would still work as long as it can contract and expand under stress. If you in a crude way look at a differential cube of that liquid omega= (k/m)^1/2. K is the water stiffness index and m is its mass.&lt;/p&gt;&#xA;" OwnerUserId="5697" LastActivityDate="2016-06-20T21:58:52.837" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8226" PostTypeId="1" AcceptedAnswerId="8233" CreationDate="2016-06-21T00:53:56.043" Score="5" ViewCount="984" Body="&lt;p&gt;About 71% of the Earth's surface is covered with water and the remaining 29% is landmass&lt;a href=&quot;https://en.m.wikipedia.org/wiki/Earth&quot; rel=&quot;noreferrer&quot;&gt;*&lt;/a&gt;. If you could theoretically cut the planet in half, with the objective of producing a half with the most landmass possible (and another with the most water possible), where would the cut be? More specifically, where would the centers (in the surface) of both halves be located?&lt;/p&gt;&#xA;" OwnerUserId="6180" LastEditorUserId="6180" LastEditDate="2016-06-21T00:59:11.897" LastActivityDate="2016-07-05T02:41:06.910" Title="Half of Earth with most landmass" Tags="|geography|land-surface|earth-system|ocean-models|land-surface-models|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8227" PostTypeId="2" ParentId="7688" CreationDate="2016-06-21T02:17:30.447" Score="4" Body="&lt;p&gt;Actually, there are plenty of alternative DC Inversion software;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hate using res2dinv; unfortunately it's relatively easy to get into. I would have much preferred ZondRes2D for it's user experience.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Look up DC2DInvRes (Resistivity.net), and BERT by Thomas Gunther. You may need to contact Thomas for Bert codes, however it's all done in Python and easily read. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is another one, but in matlab. (&lt;a href=&quot;http://www.degruyter.com/view/j/acgeo.2015.64.issue-2/acgeo-2015-0071/acgeo-2015-0071.xml&quot;&gt;http://www.degruyter.com/view/j/acgeo.2015.64.issue-2/acgeo-2015-0071/acgeo-2015-0071.xml&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here in another, again in matlab.&#xA;&lt;a href=&quot;https://github.com/cageo/Karaoulis-2013&quot;&gt;https://github.com/cageo/Karaoulis-2013&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6181" LastActivityDate="2016-06-21T02:17:30.447" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8228" PostTypeId="2" ParentId="8222" CreationDate="2016-06-21T06:56:25.837" Score="0" Body="&lt;p&gt;The most effective geometry for gravity is a sphere. Mountain top is farther from center of earth and the density of basalt or granite is less than the mantle or the earth core. Imagine an oblong earth ultimately similar to a rectangular shape but same mass.&lt;br&gt;&#xA;If you would measure the gravity on the tip of this rectangle it would be lees even though it is on top of a huge mass.&lt;br&gt;&#xA; The fact that planets are round indicates all the heavy primitive crest unevenness has crashed down to surface but kept afloat by the lateral pressure if adjacent material compressed by higher gravity than what was available at the altitude.&lt;/p&gt;&#xA;" OwnerUserId="5697" LastActivityDate="2016-06-21T06:56:25.837" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8229" PostTypeId="2" ParentId="8222" CreationDate="2016-06-21T09:03:39.420" Score="8" Body="&lt;p&gt;I gave this one some thought and ran some numbers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The real answer to your question is that you would be lighter because the material that makes up continental plates is lighter than the basalt rock under it.  It might not look that way but continents, mountains and oceans are actually balanced with about equal weight under them.  Continents are above sea level because of larger amounts of crust which is lighter than basalt.  The earth, which is pretty malleable as a whole, adjusts for significant unbalanced changes in mass, it's still rebounding from the melted glaciers from the last ice age for example.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This happens with Mountains too, also slowly, but mountains are formed over millions of years so the adjustment has time to take place.  Mountains are formed when two continental plates push against each other, one slides under the other, so both what forms the mountain, and what goes under the mountain is lighter than basalt under the Earth's crust.   When you climb a mountain, you're not actually on top of more mass because much of the rock under you is lighter rock.  Mountains are actually puffy (I always wanted to say that).    If mountains were actually greater mass relative to the (relatively) spherical Earth, then they'd sink into the Earth, which they do to some extent, but, as I said above, Mountains are &lt;strike&gt;puffy&lt;/strike&gt; buoyant compared to the Earth's crust, so the mass is pretty much the same on top of the mountain and at the foot of the mountain.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tBBcO.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tBBcO.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's not to say the Earth is perfectly balanced, it's definitely not, but the imbalance doesn't appear to follow mountain ranges.  Google &quot;Earth Gravity Map&quot; for more on that.  Article with pretty picture &lt;a href=&quot;http://news.bbc.co.uk/2/hi/sci/tech/8767763.stm&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I suspect, your question wasn't just real world but also a mathematical query, so, moving on.   If we create a cone shaped mountain, a large flat one, lets say it's 6.371 km tall (reason I picked that number will become clear soon), and lets give it 4 times that as a radius or 25.484 km radius to it's base and a specific density of 2.7, the mass of our mountain, using 1/3 base times height is:  3.1416 * .333333 * 2.7 * 25,484^2 * 6,371 * 1000  (the 1,000 is for density of 1,000 KG per cubic meter at specific density of 1) = about 1.17x10^16 KG.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, on top of this artificial mountain that, if it was actually added to the earth, it would push the earth down and the earth would adjust it's mass around it over time, but ignoring that, the mountain is 1/1000th the radius of the earth so the distance from the Earth's center is increased by 0.1%&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mass of the mountain, 1.17E16kg is about 1/510,000,000 the mass of the Earth, 5.97E24kg, So we have a mass increase of about 0.0000002% and a corresponding reduction in gravitation by increased distance to the center of the earth (the square of 0.1%), or 0.0001.   or, 510 times as much is lost by the higher altitude than is gained by the increase in mass.  Now if you make the mountain flat enough, you'd probably be able to increase gravity the tiniest bit, but past a certain point the foot of the mountain is so spread out that the calculation grows inaccurate.  The short answer is simply, no, as the other two posters have said.  The mass of any mountain is simply insufficient to increase the force of gravity more than it loses by what's lost in the higher altitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A 3rd real factor, completely unrelated to your question is air density.  Heavier air does create some buoyancy which reduces our weight and the gravity we feel, this effect varies with high and low pressure and temperature, but on an average day at sea level air buoyancy reduces our mass by about .12%, so if you weighed yourself in a vacuum chamber vs your regular bathroom routine, you'd find you weigh about 2 or 3 ounces more for an average person.   Climb a mountain, the thinner air, you might gain an ounce due to loss of air buoyancy and that more than makes up for any small changes in gravity, so if you measure gravity by a scale and a weight, things weigh more on top of a mountain, because of thinner air, even though the G force is slightly lower.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rotation of the earth and the centrifugal force also decreases mass, depending on how close the mountain is to the equator, (see picture).  as does the bulge of the Earth around it's equator, but all these changes are tiny.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/t30rF.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/t30rF.gif&quot; alt=&quot;https://qph.ec.quoracdn.net/main-qimg-58036f61af8f1d01722b7149dda1bc5a&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2016-06-21T22:36:30.063" LastActivityDate="2016-06-21T22:36:30.063" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8230" PostTypeId="1" AcceptedAnswerId="8232" CreationDate="2016-06-21T09:29:44.620" Score="11" ViewCount="3272" Body="&lt;p&gt;The Medieval Warm Period (MWP) or Medieval Climatic Anomaly was a time from about 950 to 1250 when climate was warmer than in the timespans immediately before and after.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is if this warming lead to significant changes in sea level and how these looked like around western Europe, how the sea levels developed during this time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the change in temperature was not globally uniform, it is of course possible that the sea level changes didn't amount to much.&lt;/p&gt;&#xA;" OwnerUserId="117" LastEditorUserId="87" LastEditDate="2016-06-21T11:30:30.897" LastActivityDate="2022-12-16T14:30:36.810" Title="How were the sea levels around western Europe during the Medieval Warm Period?" Tags="|climate-change|paleoclimatology|sea-level|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8231" PostTypeId="2" ParentId="8226" CreationDate="2016-06-21T10:37:12.200" Score="8" Body="&lt;p&gt;You would have to cut somewhere along this circle:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bpm2E.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bpm2E.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only landmass here is New Zealand, eastern Australia, eastern PNG, western North America and some Pacific islands. I'm pretty sure you can tweak it a bit, but that's the basic idea.&#xA;Notice that this actually shows less than a half because of the relatively low altitude. If you &quot;zoom out&quot; infinitely you'll get some more Australia and more America in this, but it's still going to be mostly ocean.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-06-21T10:37:12.200" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8232" PostTypeId="2" ParentId="8230" CreationDate="2016-06-21T13:51:10.247" Score="4" Body="&lt;p&gt;In the global sense the sea level data are not entirely consistent, but then, there are always going to be apparent variations when you are comparing proxy data from different sources. As far as Europe is concerned sea level rose between 1.0 and 1.6 metres throughout the Medieval Warm Period - or maybe as much as 2.0 metres by some of the more extreme estimates. Following this was the 'little ice age' (actually not an ice age at all), when sea level fell by almost as much. See for example the graphs of Behre 2004, and Puls, 2008, (German North Sea coast),both of which are reproduced in Kwaad's paper, which is a good overview.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.kwaad.net/SeaLevel-MiddleAges-LittleIceAge.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.kwaad.net/SeaLevel-MiddleAges-LittleIceAge.html&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whatever sea level change you regard as definitive, the important point is that these were just minor variations superimposed upon a major sea level trend. Overall the post-glacial sea level, from about 8000 years ago, was a rapid rise from -50 metres (or so), flattening off during the last two millennia, and now massively accelerating again, primarily due to human-induced climate change.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-21T13:51:10.247" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8233" PostTypeId="2" ParentId="8226" CreationDate="2016-06-21T14:07:27.523" Score="2" Body="&lt;p&gt;It's a moot point, and probably varies somewhat according to the state of the tide. Visually, however, the 'pole of maximum ocean' is about half-way between two atolls in the south Pacific: Tautua, 9&amp;deg;00' S; 157&amp;deg;58' W, and Starbuck Island, 5&amp;deg;38' S; 155&amp;deg;53' W. (Not that I wish to give overpriced and over-rated coffee any undue publicity!). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;By the same token, the pole of maximum land must be 180 degrees different in lat and long  - I leave you to figure that out :-)&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="111" LastEditDate="2016-07-05T02:41:06.910" LastActivityDate="2016-07-05T02:41:06.910" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8234" PostTypeId="1" CreationDate="2016-06-21T16:17:05.560" Score="0" ViewCount="99" Body="&lt;p&gt;What is the popular opinion on this &quot;Planet X&quot; news that I have been seeing? It makes me a little nervous sometimes... I read so much on the internet about this subject and do not know what to believe... Can anyone help?&lt;/p&gt;&#xA;" OwnerUserId="6184" LastActivityDate="2016-06-21T17:07:12.207" Title="Nibiru, or Planet X" Tags="|hypothetical|" AnswerCount="1" CommentCount="5" ClosedDate="2016-06-22T07:17:07.777" ContentLicense="CC BY-SA 3.0" />
  <row Id="8235" PostTypeId="2" ParentId="8234" CreationDate="2016-06-21T17:07:12.207" Score="2" Body="&lt;p&gt;There's nothing to be worried about. There's no magical Niburu or Planet X, if anything then Planet 9 might exist. &#xA;There was a recent &lt;a href=&quot;https://arxiv.org/abs/1601.05438&quot; rel=&quot;nofollow&quot;&gt;research paper&lt;/a&gt; that looked at the orbital elements of some trans-Neptunian objects and their curious clustering. The paper suggested that a possbile explanation for this clustering might be shepherding by a possible ninth planet in the solar system.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then the media made up big stories about magical objects in the sky that have nothing to do with Planet 9. Also I believe this question rather belongs into the astronomy section.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2016-06-21T17:07:12.207" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8236" PostTypeId="2" ParentId="8191" CreationDate="2016-06-21T17:24:38.857" Score="-1" Body="&lt;p&gt;Central Florida is a zone of convergence; prevailing winds from the north crash into prevailing winds from the south.  The result is a lot of storm activity and a lot of lightning.&lt;/p&gt;&#xA;" OwnerUserId="6185" LastActivityDate="2016-06-21T17:24:38.857" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8237" PostTypeId="2" ParentId="8220" CreationDate="2016-06-22T05:32:11.900" Score="1" Body="&lt;p&gt;Since this is the Earth Science stack exchange I assume you are talking about the Earth's exosphere, in which case the first issue to decide is how one defines the exosphere - there are several definitions. The lower boundary is straight forward - the thermosphere. However, the exosphere doesn't have a clearly defined upper boundary. You could argue that any gas molecule that is gravitationally bound to Earth is within the exosphere, but that depends upon the relative forces of solar wind and gravity, which is a variable. Some argue that the outer limit is defined by the geocorona at about 10,000 km, whereas the gravitational limit is more than 100,000 km, or arguably up to half the distance to the moon. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The exosphere's composition varies from oxygen, carbon dioxide, hydrogen and helium at its base, to just hydrogen and helium in the outer limits.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The exosphere's pressure is about 0.0007 atmospheres at its base to virtually nothing in the outer reaches. In fact 'pressure' is a meaningless concept in the outer exosphere because individual atoms and molecules are kilometers to hundreds of kilometers apart, so they almost never interact - and pressure is really the intensity of molecular physical interaction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A comparable argument applies to the exosphere's temperature. In the outer regions of the exosphere the same hydrogen molecule could have a daytime temperature of nearly 2000 Kelvin, and a night-time temperature close to zero Kelvin. In both cases the space would feel cold because there is next to nothing there to transmit heat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth's atmosphere is still evolving by processes dominated by the lithosphere / biosphere. Only hydrogen and helium are light enough to shoot up to the top of the atmosphere (think helium weather balloons). At the height and temperature of the thermosphere, or higher, they can both gain sufficient thermal kinetic energy from sunlight to gain escape velocity, which is why there is very little helium or free hydrogen in our atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-22T05:32:11.900" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8238" PostTypeId="1" CreationDate="2016-06-22T07:44:16.197" Score="3" ViewCount="394" Body="&lt;p&gt;The buoyancy frequency, $N$ is defined as $N^2=\frac{gd\theta}{\theta dz}$, where $\theta$ is the potential temperature (I see it as a measure of the deviation from the adiabatic nature), &#xA;$z$ is the vertical co-ordinate and &#xA;$g$ is the acceleration due to gravity and sometimes $\theta$ is replaced with potential density. My question is why not use $T(z)$ (usual temperature) instead of $\theta(z)$ to define $N$?&lt;/p&gt;&#xA;" OwnerUserId="5378" LastActivityDate="2023-04-23T02:00:27.530" Title="Buoyancy frequency" Tags="|atmosphere|temperature|atmospheric-circulation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8239" PostTypeId="1" CreationDate="2016-06-22T10:35:50.713" Score="1" ViewCount="96" Body="&lt;p&gt;If one was to quantify the shape (particularly roundness) of detrital zircon grains, would there be a correlation between the age of the detrital zircon grains and their shape? For example, if the grain is an Archaean one, would it be much more rounded than a grain that is Devonian?&lt;/p&gt;&#xA;" OwnerUserId="6083" LastActivityDate="2016-06-22T10:35:50.713" Title="Would you see a correlation between detrital zircon age and grain shape?" Tags="|geology|geochemistry|sedimentology|geochronology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8240" PostTypeId="2" ParentId="8239" CreationDate="2016-06-22T10:35:50.713" Score="2" Body="&lt;p&gt;My thought is that you would not see any correlation because grain roundness has to do with how long it has been in the sedimentary system rather than its crystallisation age. That is, if one sampled a modern sediment in which a 650 Ma zircon grain from a 650 Ma granite has only recently been eroded from its granite source then one would expect this zircon to be euhedral (and this is not taking into account magmatic effects like resorption which would affect its shape!). But a 650 Ma zircon in the same sediment may have been eroded from a different Neoproterozoic granite during the Cambrian, in which case one would expect that it has been rounded by multiple cycles of sedimentation. Therefore no correlation could be made between the shape of the zircon grains and their crystallization age.&lt;/p&gt;&#xA;" OwnerUserId="6083" LastActivityDate="2016-06-22T10:35:50.713" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8241" PostTypeId="1" AcceptedAnswerId="8246" CreationDate="2016-06-22T15:19:53.277" Score="5" ViewCount="209" Body="&lt;p&gt;I'm working on &lt;a href=&quot;http://www.kd7uiy.com&quot;&gt;piecing together a game that involve sea trading&lt;/a&gt;, loosely based on historical conditions. As a part of making the game, I'm creating a map. From that map, I'm trying to determine what the temperature is, at least on average, for a number of reasons. I'm also going to include a seasonal model to it. What I'm trying to do is to find a first order estimate of the average temperature by day and by latitude, at sea level. I know that this varies tremendously based on a number of factors, but it seems to me that assuming equal distance to the sun, a perfectly spherical Earth with a known axial tilt, and some other reasonable assumptions, there should be a model that will work, which I can add to some noise to cover some of the other sources of error.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bottom line, is there a relatively simple model of latitude and time of year vs average temperature at sea level? Bonus points if it includes a difference by altitude. Thanks!&lt;/p&gt;&#xA;" OwnerUserId="6151" LastEditorUserId="543" LastEditDate="2016-06-23T04:18:30.277" LastActivityDate="2016-06-23T04:18:30.277" Title="Is there a simple temperature prediction model?" Tags="|meteorology|temperature|models|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8242" PostTypeId="1" CreationDate="2016-06-22T16:19:26.690" Score="8" ViewCount="5276" Body="&lt;p&gt;I know that the standard Mercator projection is completely wrong when it comes to the relative sizes of countries (Greenland appears relatively much larger than in reality, for example). AFAIK they do this because the focus of Mercator isn't realism, but to keep routing working correctly (ships and airplanes for example).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But: is there a map that correctly displays the relative size of every country?&lt;/p&gt;&#xA;" OwnerUserId="6194" LastEditorUserId="28050" LastEditDate="2016-06-23T19:23:54.357" LastActivityDate="2020-10-31T17:56:08.287" Title="Is there a map that displays every country at its correct relative size?" Tags="|geography|cartography|mapping|projection|" AnswerCount="3" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="8243" PostTypeId="1" CreationDate="2016-06-22T20:33:23.603" Score="6" ViewCount="266" Body="&lt;p&gt;I am seeking a physical explanation for this;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is huge amount of such a Forest rings in Earth; &lt;a href=&quot;https://www.google.com/maps/@49.2696786,-83.7508143,2077m/data=!3m1!1e3&quot; rel=&quot;noreferrer&quot;&gt;(Link to Google Maps to one ~400 m Ring)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;They range in diameter from 30 metres to 2 kilometres, with the&#xA;  average ring measuring about 91 metres across. Over 2,000 of these&#xA;  forest rings have been documented, but scientists estimate the actual&#xA;  number is more than 8,000. Forest rings in Canada&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7I5tQ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7I5tQ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question relates to &lt;a href=&quot;http://www.fodden.com/rings-in-ontarios-north/&quot; rel=&quot;noreferrer&quot;&gt;following observation&lt;/a&gt;;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;There seem to be giant electromagnetic disturbances in the soil and&#xA;  subsoil that affect not merely growth of vegetation over large areas&#xA;  but also the level of the water table: it rises “against” gravity&#xA;  within the circle.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.bldgblog.com/2016/01/rings/&quot; rel=&quot;noreferrer&quot;&gt;Behind the link&lt;/a&gt; in the given link it's said more clearly;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;But it gets weirder: as Hamilton’s fieldwork also revealed, there is a&#xA;  measurable “bulge in the water table that occurs over the entire&#xA;  length of the forest ring with a profound dip on the ring’s outer&#xA;  edge.” For Hamilton, this effect was “beyond science fiction,” he&#xA;  remarked to the trade journal Northern Ontario Business, “it’s&#xA;  unbelievable.”&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;What this means, he explained, is that “the water is being held up&#xA;  against gravity” by naturally occurring electrical fields.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And further from The Journal Ontario Business;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Hamilton was testing an analytical technique over a Matheson gold&#xA;  deposit to determine if there was any kind of geochemical surface&#xA;  signal. To his surprise, there were signals coming through 30 to 40&#xA;  metres of glacial clay.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;“We’re thinking there’s no way metals can move through clay 10,000&#xA;  years after glaciation.”&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;After ruling out transport by ground water, diffusion and gas, he&#xA;  theorized it had to have been lifted to surface on electrical fields.&#xA;  He applied the same theory to forest rings and discovered that they&#xA;  were also giant negatively charged cells.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Water does react to magnetic&#xA;field. But the needed $10T$ to make it lavitate is way too much&#xA;compared to Magnetic field earth provides; it's just $0.00005T$ and we&#xA;should be talking only some reasonable scale variations here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;QUESTION; Why is ground water rising on these forest rings?&#xA;The most obvious one would be dissolved gases. &lt;a href=&quot;http://www.egs.ab.ca/resources/Documents/Hamilton_Talk_4-Forest_rings.pdf&quot; rel=&quot;noreferrer&quot;&gt;And this paper&lt;/a&gt; does provide information to this direction. But with closer study, &lt;a href=&quot;http://iopscience.iop.org/article/10.1088/0026-1394/21/1/005/meta&quot; rel=&quot;noreferrer&quot;&gt;the influence of the gases can be only 0.16 ppm.&lt;/a&gt; This means that the density change must come from water temperature. It can't come from the Ice deep below the ground. There is a measured temperature drop in the edge of the ring, but the inside outside of the ring seems to have approx. the same temperature near the soil surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cY7lP.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cY7lP.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's hard to see how coverd ice would explain the perfect ring shape (up to 2 km in diameter!)? and the landscape is not even flat. (&lt;a href=&quot;https://en.wikipedia.org/wiki/Pingo#Formation&quot; rel=&quot;noreferrer&quot;&gt;Pingo's formates&lt;/a&gt; in dried lakes/flat grounds) And why there is up to 2 meters soil depression in the annulus? Why there is negative &lt;a href=&quot;https://en.wikipedia.org/wiki/Reduction_potential&quot; rel=&quot;noreferrer&quot;&gt;reduction anomaly&lt;/a&gt; in the center of the rings? &lt;a href=&quot;https://www.researchgate.net/publication/258630258_Brauneder-OGSOFR2008&quot; rel=&quot;noreferrer&quot;&gt;There seems to be some Ice deposits in the ring edge.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To point out the Physical problem of this; Rising ground water with 10 cm on $r=1km$; $A=3140000m2$ area needs quite huge continuous power source.&lt;/p&gt;&#xA;" OwnerUserId="3098" LastEditorUserId="3098" LastEditDate="2016-06-23T10:04:29.963" LastActivityDate="2016-06-23T10:04:29.963" Title="Why is ground water rising on these forest rings?" Tags="|geophysics|geothermal-heat|forest|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8244" PostTypeId="2" ParentId="8242" CreationDate="2016-06-22T22:33:59.990" Score="6" Body="&lt;p&gt;This is pretty straight forward.  The traditional map is very good for longitude and latitude.  It's pretty lousy for the shapes and sizes of the continents cause everything close to the poles is expanded.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A more accurate map has to look like a carved up sphere on a flat sheet of paper.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This one claims to be the most accurate:  &lt;a href=&quot;https://i.stack.imgur.com/KamoV.jpg&quot; rel=&quot;noreferrer&quot;&gt;https://i.stack.imgur.com/KamoV.jpg&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's another nice accurate one but, I think, harder on the eyes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nGqzU.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nGqzU.png&quot; alt=&quot;http://www.read.seas.harvard.edu/~kohler/z/icsilogo/isf-n9.png&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any 2D map that bulges in the middle is significantly improved over the traditional flat map.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WEmi9.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WEmi9.gif&quot; alt=&quot;http://kartoweb.itc.nl/geometrics/Bitmaps/robinson1.gif&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and I like this method as a clever heart shape, which more accurately shows the countries in real size.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pOeSv.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pOeSv.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and the Peters projection is sometimes used but I don't like it because it doesn't accurately show the shapes of the nations near the poles.   It flattens them when it should squash them so in some ways it's even less accurate.  link &lt;a href=&quot;http://livelearnevolve.com/peters-projection-world-map/&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think the most accurate are easily the first two, or just use a globe and a 2D map, knowing it's inaccurate.   All this is easily available with a quick google search &quot;best 2D world map&quot;.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2016-06-22T22:33:59.990" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8245" PostTypeId="2" ParentId="8243" CreationDate="2016-06-23T02:20:38.093" Score="5" Body="&lt;p&gt;Nobody knows - yet. But one can say that these rings are too numerous and too regular in shape to be related to either kimberlites or (even more bizarrely) Oklo-type natural nuclear reactors, as some have suggested.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For what it is worth, here is my own hypothesis: The areas concerned are all periglacial in an area of abundant boulder clay. In colder analogues, particularly in Siberia and further north in Canada, such environments contain 'pingoes' &lt;em&gt;aka&lt;/em&gt; 'hydroloaccoliths', which are frost heaves in the shape of ice lenses. See, for example, &lt;a href=&quot;https://en.wikipedia.org/wiki/Pingo&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Pingo&lt;/a&gt; . These are feedback processes of circular ice formations which develop in permafrost tundra areas. The circles you refer to are exactly the right shape, diameter, distribution density, and geology to be 'fossil' (melted) pingoes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider what happens when a pingo develops. The ground is highly crazed with fractures over a disk shaped area. If there is brackish groundwater in the area then the ice freezes as pure water, thereby partitioning more saline groundwater to the perimeter - thereby leaving a high-salinity ring of brackish water which subsequently stunts tree growth (as you observe). When the ice eventually melts the pingo collapses to appear much like the surrounding boulder clay, but with a fractured and much more porous texture. Wherever there is a confined or semi-confined aquifer - which is very common because thick layers of impervious boulder clay behave as a confining layer - there will be a tendency for groundwater to rise as artesian (non-overflowing) conditions. Hence the 'bulge' of the apparent water table, which you also observe.  If this explanation is correct then the ring would be a natural exit and pressure release point for confined groundwater, and hence for entrained methane. Methane builds up under boulder clay, especially where the clay overlies peat deposits, such that oxidizing organic matter reduces the water. Moreover, this redox contrast, between surrounding oxidized near-surface/perched groundwater, and the reduced groundwater exiting from the ring, would also influence the nutrient availability, thus contributing to the ring of stressed vegetation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the change in electrical potential, that is easily explained as deriving from the contrast between normal and residual more saline groundwater. Also, if the pingo was weathered during its evolution, then there would be a difference in clay content, which would also contribute to the electrical differential. Indeed, that is to be expected when a hill (the pingo) is drained by meteoric water, taking with it any dispersive clay (another common feature of boulder clay).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So no, sorry to disappoint, but the explanation is probably just normal periglacial hydrogeology - no gold deposits involved.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The test to verify this hypothesis? It needs someone to run a traverse across such a ring, measuring the hydrostatic pressure variation (horizontal and vertical), soil salinity, and soil clay content. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-23T02:20:38.093" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8246" PostTypeId="2" ParentId="8241" CreationDate="2016-06-23T02:35:05.197" Score="5" Body="&lt;p&gt;Simple? Depends upon the level of accuracy you are looking for. Insolation alone is a rough indicator of sea surface temperatures.&lt;br&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/8gGs3.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8gGs3.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;image from &lt;a href=&quot;http://www.ospo.noaa.gov/Products/ocean/sst/contour/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.ospo.noaa.gov/Products/ocean/sst/contour/&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In more detail SSTs around the globe are significantly influenced by oceanic currents which, in turn, are very strongly influenced by the distribution of continents. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-23T02:35:05.197" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8247" PostTypeId="2" ParentId="8221" CreationDate="2016-06-23T10:39:32.620" Score="1" Body="&lt;p&gt;This question is handeled pretty throughly in Physics site; &#xA;&lt;a href=&quot;https://physics.stackexchange.com/questions/214042/earths-kinetic-energy-change&quot;&gt;https://physics.stackexchange.com/questions/214042/earths-kinetic-energy-change&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your question; &quot;How big is the difference?&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Body Tides Summarize&lt;br&gt;&#xA;0.3 ms for a 14 day period.&lt;br&gt;&#xA;0.16 ms for a 28 day period&lt;br&gt;&#xA;0.14 ms for 1/2 year period&lt;br&gt;&#xA;0.02 ms for a year period.&lt;br&gt;&#xA;0.126 ms for Lunar node period; (18.6 years)  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ocean Tides&lt;br&gt;&#xA;Max 0.05 ms for a 14 days period&lt;br&gt;&#xA;0.026 ms for a Years period&lt;br&gt;&#xA;0.024 ms for lunar node period  &lt;/p&gt;&#xA;" OwnerUserId="3098" LastEditorUserId="-1" LastEditDate="2017-04-13T12:40:15.470" LastActivityDate="2016-06-23T10:39:32.620" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8248" PostTypeId="2" ParentId="8242" CreationDate="2016-06-23T11:55:10.297" Score="13" Body="&lt;p&gt;&lt;strong&gt;Yes.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Every &lt;em&gt;equal-area&lt;/em&gt; map displays all countries (and other areas) in their correct relative size. Inevitably, they don't show the correct shape (unless you're looking at a globe). Personally, my favourite projections are pseudocylidrical equal-area projections, such as:&lt;/p&gt;&#xA;&lt;h2&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Equal_Earth_projection&quot; rel=&quot;nofollow noreferrer&quot;&gt;Equal Earth projection&lt;/a&gt;&lt;/h2&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/6/61/Equal_Earth_projection_SW.jpg/1024px-Equal_Earth_projection_SW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/6/61/Equal_Earth_projection_SW.jpg/1024px-Equal_Earth_projection_SW.jpg&quot; alt=&quot;Equal Earth projection&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;h2&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Mollweide_projection&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mollweide projection&lt;/a&gt;&lt;/h2&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5X1NP.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5X1NP.jpg&quot; alt=&quot;Mollweide projection&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;h2&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Eckert_IV_projection&quot; rel=&quot;nofollow noreferrer&quot;&gt;Eckert IV projection&lt;/a&gt;&lt;/h2&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Dpkk6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Dpkk6.jpg&quot; alt=&quot;Eckert IV projection&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;h2&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Tobler_hyperelliptical_projection&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tobler hyperelliptical projection&lt;/a&gt;&lt;/h2&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jmH1u.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jmH1u.jpg&quot; alt=&quot;Tobler hyperelliptical projection&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;There are others; &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_map_projections#Table_of_projections&quot; rel=&quot;nofollow noreferrer&quot;&gt;see this list on Wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The pseudocylindrical part means that lines of latitude are horizontal lines. I think that for any non-polar projection in the Earth sciences, this is a highly desirable property. A truly cylindrical projection means a projection onto a rectangle, but that just makes distortions even worse than they need to be.  There are other practical considerations, such as whether the poles are points or lines and whether the outer lines of longitude are ellipsoids or sinusoids, which differ between the various examples I've listed above.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2020-10-31T17:56:08.287" LastActivityDate="2020-10-31T17:56:08.287" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="8249" PostTypeId="1" CreationDate="2016-06-23T14:25:55.463" Score="5" ViewCount="389" Body="&lt;p&gt;Imagine we could catch and store all electricity of lightning 'thrown' to earth.&#xA;Would that be hugh amount of electricity to invest in?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="64" LastEditDate="2016-06-23T23:41:42.447" LastActivityDate="2016-06-23T23:41:42.447" Title="How much energy is released a year of all the lightning on earth?" Tags="|meteorology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8250" PostTypeId="1" AcceptedAnswerId="8261" CreationDate="2016-06-23T16:48:10.323" Score="1" ViewCount="1256" Body="&lt;p&gt;I have read about all 3 types of boundaries in the book : &quot;Essentials of Geography&quot; by Lutgens et. al. &#xA;But there is nothing mentioned about Transform Boundary and Earth's rotation effect on it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know the basics that since MoR are not always in straight lines, so there is a differential moment between two portions of the plate which cause this transform boundary that is perpendicular to the MoR.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But now, when I was reading one of the 'official' book of this subject by &lt;a href=&quot;https://en.wikipedia.org/wiki/National_Curriculum_Framework_(NCF_2005)&quot; rel=&quot;nofollow&quot;&gt;NCERT&lt;/a&gt; I got stuck on this paragraph : &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Transform Boundaries : Where the crust is neither produced nor destroyed as&#xA;the plates slide horizontally past each other.Transform faults are the planes of &#xA;separation generally perpendicular to the midoceanic ridges. As the eruptions do &#xA;not take all along the entire crest at the same time, there is a differential &#xA;movement of a portion of the plate away from the axis of the earth. Also, the&#xA;rotation of the earth has its effect on the separated blocks of the plate portions.&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://epathshala.nic.in/wp-content/doc/book/flipbook/Class%20XI/11092Fundamental%20of%20Physical%20Geography/Chapter-4/index.html#page=7&quot; rel=&quot;nofollow&quot;&gt;[This]&lt;/a&gt; is where this is mentioned.&#xA;Now I'm really not able to relate Earth's rotation, axis, and its effect on transform boundary. Neither Google is giving any meaningful result.&lt;/p&gt;&#xA;" OwnerUserId="2756" LastEditorUserId="2756" LastEditDate="2016-06-23T16:54:37.200" LastActivityDate="2016-06-25T07:36:40.580" Title="Transform Boundary and its relation with Earth's rotation" Tags="|plate-tectonics|earth-rotation|transform-fault|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8251" PostTypeId="1" CreationDate="2016-06-23T20:10:15.760" Score="4" ViewCount="3487" Body="&lt;p&gt;Im trying to create a Hovmoller diagram in MATLAB but I'm very new to programming and have no clue what to do. Im trying to do it for vorticity. Below is the code that I have currently. Any input or advice, would be greatly appreciated.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;path(path,'/Users/zoleak/Documents/');&#xA;lev_name='700';%mb&#xA;&#xA;disp(strcat('calculating mean fields...',lev_name,'mb'))&#xA;&#xA;file1 = '/Users/zoleak/Documents/Datasets/Patricia/ERAi.T.00.2015.1p5.45N45S.nc';&#xA;file2 = '/Users/zoleak/Documents/Datasets/Patricia/ERAi.U.00.2015.1p5.45N45S.nc';&#xA;file3 =  '/Users/zoleak/Documents/Datasets/Patricia/ERAi.V.00.2015.1p5.45N45S.nc';&#xA;file4 =  '/Users/zoleak/Documents/Datasets/Patricia/ERAi.GEO.00.2015.1p5.45N45S.nc';&#xA;file5 =  '/Users/zoleak/Documents/Datasets/Patricia/ERAi.VORT.00.2015.1p5.45N45S.nc';&#xA;file6 =  '/Users/zoleak/Documents/Datasets/Patricia/ERAi.PV.00.2015.1p5.45N45S.nc';&#xA;&#xA;%Read files in&#xA;lat=ncread(file1,'latitude');&#xA;lon=ncread(file1,'longitude');&#xA;levels=ncread(file1,'level');&#xA;u_data=ncread(file2,'u');&#xA;v_data=ncread(file3,'v');&#xA;vort_data=ncread(file5,'vo');&#xA;&#xA;%Format Files&#xA;x=lon(28:121);&#xA;y=lat(1:31);&#xA;[nlons,nlats,ntimes]=size(vort_data);&#xA;u_data=u_data(28:121,1:31,4,:);&#xA;v_data=v_data(28:121,1:31,4,:);&#xA;vort_data=vort_data(28:121,1:31,4,:);&#xA;&#xA;u_data=squeeze(squeeze(u_data));&#xA;v_data=squeeze(squeeze(v_data));&#xA;vort_data=squeeze(squeeze(vort_data));&#xA;&#xA;%%&#xA;&#xA;clf;&#xA;&#xA;lat_avg=mean(vort_data(5:15,:,:),1);     &#xA;&#xA;LONLIMS=[-139.5 -60];&#xA;LATLIMS=[0 30];&#xA;[lon_plot,lat_plot]=meshgrid(x,y);&#xA;proj('mercator','lon',LONLIMS,'lat',LATLIMS);&#xA;%m_quiver(lon_plot,lat_plot,u_data(:,:)',v_data(:,:)','LineStyle','-','Color',[0 0 0],'AutoScaleFactor',2);&#xA;hold on;&#xA;contourf(lon_plot,lat_plot,lat_avg(:,:)','LevelList',[-6e-4:1e-5:6e-4],'LineColor','none')&#xA;coast('patch',[1 1 1],'linewi',2);&#xA;grid('linewi',0.5,'tickdir','out','linest','none');&#xA;set(gca,'FontSize',14);&#xA;set(gcf,'Color','white');&#xA;hcb=colorbar('eastoutside');&#xA;title(['5N-20N,700mb Vorticity']);&#xA;set(hcb,'YTick',[-1e-4:1e-5:1e-4])&#xA;caxis([-.5e-4 .5e-4])&#xA;save_name1=strcat('/Users/zoleak/Documents/figures/HOVMOLLER/PAT_VORT');&#xA;print(save_name1,'dpdf'-r600);&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="6199" LastEditorUserId="2536" LastEditDate="2017-06-04T11:47:31.300" LastActivityDate="2017-06-04T11:47:31.300" Title="How to plot a Hovmoller diagram in MATLAB?" Tags="|meteorology|software|matlab|visualization|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8252" PostTypeId="2" ParentId="8249" CreationDate="2016-06-23T22:56:33.453" Score="5" Body="&lt;p&gt;Some basic math on this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;About &lt;a href=&quot;http://environment.nationalgeographic.com/environment/natural-disasters/lightning-profile/&quot; rel=&quot;noreferrer&quot;&gt;100 bolts of lightning hit the Earth every second&lt;/a&gt; and they average about &lt;a href=&quot;http://www.realclearscience.com/blog/2012/05/could-we-harness-lightning-as-an-energy-source.html&quot; rel=&quot;noreferrer&quot;&gt;a billion joules of energy be bolt&lt;/a&gt;.   That's 3.1 billion lightning strikes per year, coming to about 3.1 billion billion joules per year, or about 860 billion kilowatt-hours (kwh) of electrical energy per year.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That estimate is pretty rough as some estimates have as much as 5 billion joules per bolt of lightning, pushing it up over 4 trillion kwh/year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Total human electrical usage, per &lt;a href=&quot;https://en.wikipedia.org/wiki/World_energy_consumption&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt; is about 18.1% of 104 trillion kwh/year, 2012 numbers, 18.9 trillion kwh/year of electricity generated.    So even if all the lightning energy was utilized (which would be unlikley for a few reasons), it would be somewhere in the 4%-20% range of our total electrical demand, which isn't bad, but I think that's the answer to your question.  There's not enough energy in all the lightning on Earth to supply our electrical demand.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wikipedia has an &lt;a href=&quot;https://en.wikipedia.org/wiki/Harvesting_lightning_energy&quot; rel=&quot;noreferrer&quot;&gt;article&lt;/a&gt; on the logistical difficulties.   It's perhaps doable, to some extent, but at best, lightning could provide only a small percentage of our electrical needs, unlike solar panels which could provide, at least in total energy, well in excess of our electrical needs.   Solar runs into problems like it's not always on, which is a limiting factor to it's usefulness, but in terms of total energy provided it's much easier and much more abundant than harnessing lightning.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2016-06-23T22:56:33.453" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8253" PostTypeId="1" CreationDate="2016-06-24T00:36:20.920" Score="-2" ViewCount="156" Body="&lt;p&gt;I'm going to be doing a presentation for grade school children, and I'd like them to get a feel for how much source rock it takes to make oil. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It takes about a 10 foot layer of swamp debris to make a 1 foot layer of coal; how thick a layer of oil would that 1 foot of coal make when it converts to oil? (Think of the oil as a pure layer on top of the ground, not absorbed into some porous rock.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I realize it's not that simplistic, but I'm talking to 6 year olds, so I don't need it exact just the order of magnitude.&lt;/p&gt;&#xA;" OwnerUserId="6200" LastEditorUserId="534" LastEditDate="2016-06-24T05:54:56.453" LastActivityDate="2016-06-24T10:45:54.383" Title="How much coal does it take to generate oil?" Tags="|geology|geochemistry|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="8254" PostTypeId="1" CreationDate="2016-06-24T03:21:47.543" Score="5" ViewCount="324" Body="&lt;p&gt;In my opinion, tornado is hard to forecast in three different aspects:  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The size of tornado is about 100 ~ 1000 m which can't be represented well in weather model or detected by limited weather station.    &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The lifetime of tornado sustained is short(~hours). For now, the strong-convention activity can't be forecast well for 24 h or 48 h product.    &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The cause of tornado is complex. It also increase the uncertainty of the parameterize or numerical scheme which describe the process control the tornado.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;But, I have heard some brave guy(&lt;strong&gt;Tornado Chaser&lt;/strong&gt;) searching for tornado around US. It's really cool to experience the amazing nature  as the figure shown.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ljxOl.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ljxOl.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But how did they learned the information of &lt;em&gt;where and when a new tornado would appear&lt;/em&gt; ? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS: my question was came forward due to the sad news of 98 deaths by tornado in Jiangsu, China at 2016-06-23 &lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="5214" LastEditDate="2016-06-24T03:32:00.157" LastActivityDate="2018-05-30T10:41:03.743" Title="How does the tornado chaser locate the spot?" Tags="|meteorology|atmosphere|atmosphere-modelling|tornado|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8255" PostTypeId="1" CreationDate="2016-06-24T08:05:48.047" Score="-1" ViewCount="3040" Body="&lt;p&gt;I am wondering the difference between w-wind, vertical p-velocity and Omega.&#xA;I understand that all represents the vertical profile of Wind, but then why do we use these three different terms?&lt;/p&gt;&#xA;" OwnerUserId="3194" LastActivityDate="2016-06-25T15:54:18.387" Title="What is the difference between w-wind, vertical p-velocity and Omega?" Tags="|wind|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8256" PostTypeId="2" ParentId="8253" CreationDate="2016-06-24T10:45:54.383" Score="5" Body="&lt;p&gt;None. It does not take any coal to generate oil. Oil is not made from coal. The &lt;a href=&quot;http://www.bbc.co.uk/bitesize/standard/chemistry/materialsfromoil/how_crude_oil_was_formed/revision/2/&quot; rel=&quot;noreferrer&quot;&gt;formation process for oil&lt;/a&gt; is a different process to &lt;a href=&quot;http://www.bbc.co.uk/education/guides/z27thyc/revision&quot; rel=&quot;noreferrer&quot;&gt;that of coal&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oil is formed from marine organisms. Coal is formed from a peaty mix of dead plants.&lt;/p&gt;&#xA;" OwnerUserId="100" LastActivityDate="2016-06-24T10:45:54.383" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8257" PostTypeId="1" CreationDate="2016-06-24T14:05:46.937" Score="3" ViewCount="185" Body="&lt;p&gt;I don't know whether quartz behaves like ice or not, but could it be because silicon dioxide, which the continents are made of for a big part, is less dense - so the continents lay on top like ice on water?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="595" LastEditDate="2016-06-27T10:06:09.667" LastActivityDate="2016-06-27T10:06:09.667" Title="Do our continents lay on the mantle because solid silicon dioxide is less dense than its liquid form?" Tags="|geology|geophysics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8258" PostTypeId="1" AcceptedAnswerId="8260" CreationDate="2016-06-24T16:23:16.913" Score="1" ViewCount="92" Body="&lt;p&gt;Are the Diomede Islands part of North America or Asia?  I cannot find a credible, clear answer online.  Only that the islands were part of the land bridge between the two continents.&lt;/p&gt;&#xA;" OwnerUserId="6203" LastActivityDate="2016-06-25T07:03:53.550" Title="Diomede Islands" Tags="|mapping|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8259" PostTypeId="2" ParentId="8257" CreationDate="2016-06-25T06:46:40.133" Score="4" Body="&lt;p&gt;Even if the mantle was pure silica, it wouldn't melt at great depth because of the pressure and paucity of volatiles at that depth (which would act like fluxes, depressing the melting point). So it wouldn't behave like a solid phase floating on a chemically similar liquid phase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the most part the crust is not silica but a mix of silica and alumino-silicates of calcium, sodium and potassium, with traces of a whole lot of other stuff. The average specific gravity is about 2.8. On the other hand the mantle is predominantly a mixture of magnesium-iron silicates, with a little calcium, nickel, chromium, etc, and an average specific gravity of about 3.2.  So it is a case of silica-rich (not pure silica) rocks floating on much denser silicates, depleted in aluminium, and relatively depleted on silica. The biggest difference is the high iron content of the mantle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suspect confusion arises because many people are not clear about the distinction between quartz &lt;em&gt;silica&lt;/em&gt;, which always has a specific gravity of 2.65, and &lt;em&gt;silicates&lt;/em&gt;, where the density is highly variable between about 2.0 and 4.7.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-25T06:46:40.133" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8260" PostTypeId="2" ParentId="8258" CreationDate="2016-06-25T07:03:53.550" Score="3" Body="&lt;p&gt;From an Earth Sciences perspective there is no distinction between Asia and North America. They are geologically continuous, comprising mostly Mesozoic sediments in a block-faulted continental shelf setting. The Diomede Islands just happen to be the highest points of this tectonically complicated area. That they are islands at all is purely an accident of the current post-glacial sea level rise. The surrounding Bering Strait is only about 50 metres deep, whereas, for most of the last 2 million years the global sea level was up to 120 metres lower than present. Hence it is only recently that the Diomedes became islands at all. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-25T07:03:53.550" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8261" PostTypeId="2" ParentId="8250" CreationDate="2016-06-25T07:36:40.580" Score="1" Body="&lt;p&gt;NCERT is an Indian document written from the perspective of the prevailing non-scientific educational culture, in which (for example) astrology is considered to be bona-fide science! Therefore it is not authoritative, and certainly not written accurately from the perspective of peer-reviewed scientific sources. It has been criticized before, and in this case it is quite incorrect to write that transform faults are significantly affected by the Earth's rotation. Rather, the NCERT quotation that you cite seems to confuse the &lt;em&gt;Earth&lt;/em&gt;'s pole of rotation with the &lt;em&gt;Euler&lt;/em&gt; pole of rotation. The latter is a key concept of the plate tectonic movement between any two plates. The Euler pole of rotation can be at any angle with respect to the Earth's rotational axis. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-25T07:36:40.580" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8262" PostTypeId="2" ParentId="8255" CreationDate="2016-06-25T15:54:18.387" Score="6" Body="&lt;p&gt;I haven't come across the vertical p-velocity, so I am unsure what that is trying to communicate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;w is the vertical velocity with units of length per second. Travelling away from the surface means that w is positive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Omega is the vertical velocity in pressure coordinates (so positive omega is negative w). Omega has units of pressure per time. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because much of the operational meteorology uses pressure surfaces, omega is a more common quantity to see. &lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2016-06-25T15:54:18.387" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8263" PostTypeId="2" ParentId="7537" CreationDate="2016-06-26T09:37:45.293" Score="1" Body="&lt;p&gt;Some difference i photography is obvious. Insat does not provide images of scattered, light clouds which are essential for a lay observer to form a view about possibility of rain.&lt;/p&gt;&#xA;" OwnerUserId="6207" LastActivityDate="2016-06-26T09:37:45.293" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8264" PostTypeId="1" AcceptedAnswerId="8266" CreationDate="2016-06-26T10:42:42.197" Score="1" ViewCount="67" Body="&lt;p&gt;Map-making requires two distinct processes, first to produce the data -- latitude, longitude and elevation -- of the points to be mapped; and second to represent this data on a flat surface as a map. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cartography nicely covers the science of creating the map from the data -- plotting points to give an accurate representation of desired properties, realising that at least one of shape, area, direction or distance, has to be sacrificed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there an overall name for the initial gathering of data? Terms like &quot;surveying&quot; seem to me to be too specialised or limited to cover all the processes involved, and &quot;topography&quot; seems too broad.&lt;/p&gt;&#xA;" OwnerUserId="4541" LastActivityDate="2016-06-26T15:59:09.590" Title="Is there a name for the process of producing positional data for cartography?" Tags="|geography|cartography|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8265" PostTypeId="2" ParentId="8264" CreationDate="2016-06-26T14:15:30.223" Score="2" Body="&lt;p&gt;Surveying is the process of taking topographical measurements of latitude, longitude and elevation. It is also the process of marking out lines for engineering/construction designs of such things as roads, tunnels, fence lines, boundaries &amp;amp; foundations of buildings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Surveying provides the topographical data that cartographers, engineers and other professionals use for their purposes.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-06-26T14:15:30.223" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8266" PostTypeId="2" ParentId="8264" CreationDate="2016-06-26T15:59:09.590" Score="0" Body="&lt;p&gt;Thank you @Fred. Surveying and Topography do cover it but they both have wider meanings than the restricted use I am after.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Topometry&lt;/strong&gt; is the closest official word I have found. Here is the definition from the Wiktionary:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Noun&lt;/strong&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;strong&gt;topometry&lt;/strong&gt; ‎(uncountable)&#xA;       (chiefly medicine) Any of various imaging or surveying techniques in which the three-dimensional positions of an array of points is&#xA;  recorded.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The combinatiom of &quot;topo&quot; for shape and &quot;metry&quot; for measurement seems to cover it nicely. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, adding &quot;geo&quot; for the earth, I would like to coin the word &lt;strong&gt;Geotopometry&lt;/strong&gt; to express the exact meaning I am after, although my spell checker doesn't like it, and probably not many people will know what I mean when I use it.&lt;/p&gt;&#xA;" OwnerUserId="4541" LastActivityDate="2016-06-26T15:59:09.590" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8267" PostTypeId="1" AcceptedAnswerId="8296" CreationDate="2016-06-26T17:28:08.663" Score="6" ViewCount="31031" Body="&lt;p&gt;I picked up this stone form a beach on the south coast of England (lancing). How is it possible it has such round holes? Plenty of stones looked similar. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nFjU4.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nFjU4.jpg&quot; alt=&quot;Stone with hole&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6210" LastActivityDate="2020-01-25T15:03:49.677" Title="Cause for round holes in stones" Tags="|geology|" AnswerCount="6" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8268" PostTypeId="1" AcceptedAnswerId="8270" CreationDate="2016-06-26T18:27:34.643" Score="1" ViewCount="182" Body="&lt;p&gt;We know how tornadoes form: when areas of hot air and cold air mingle, causing rotation. We can even see them form on the radar. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yet, for all of our technology, we can't stop such events from happening - even though we &lt;strong&gt;can&lt;/strong&gt; cause it to rain by seeding clouds. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But if someone were at the area that a tornado was about to form and was able to introduce an area of super-heated or super-cooled air into the potential tornado, would it destabilize the formation of the destructive whirlwind? Or would doing such a thing cause more of them to form or for them to form more quickly and/ or be more damaging?  &lt;/p&gt;&#xA;" OwnerUserId="6211" LastEditorDisplayName="user1161" LastEditDate="2017-07-01T22:32:13.600" LastActivityDate="2017-07-01T22:32:13.600" Title="Could a large burst of super-heated or super-cooled air cause tornadoes to fall apart?" Tags="|meteorology|weather-forecasting|tornado|thunderstorm|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8270" PostTypeId="2" ParentId="8268" CreationDate="2016-06-26T23:04:40.557" Score="2" Body="&lt;p&gt;Changing air currents is very difficult and energy intensive.  You'd need to alter an entire weather system - no easy feat.  If you heated a very large region of cool air you might prevent the spiraling that causes tornadoes to form, but you'd need to warm at least few states worth of upper atmosphere.   It would be an enormous undertaking.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's also the logistical problem of how would you go about doing it?   Heating in principal can be done faster than cooling, presumably sending up a whole lot of hydrogen in a few hundred balloons and igniting it forming hot water-vapor, which as it condenses, would further heat the atmosphere.    Cooling warm air is harder as there's no quick and easy method to cool an enormous  volume of air, so I think heating the high cold air would be easier than cooling the low moist air, but it would still be an enormous effort and probably cost more in prevention than the tornadoes are likely to do in total damage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://images.slideplayer.com/22/6379142/slides/slide_22.jpg&quot; rel=&quot;nofollow&quot;&gt;http://images.slideplayer.com/22/6379142/slides/slide_22.jpg&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's no neat and tidy technological trick to get it done that I can think of.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2016-06-27T03:38:51.930" LastActivityDate="2016-06-27T03:38:51.930" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8272" PostTypeId="2" ParentId="8267" CreationDate="2016-06-27T01:49:52.687" Score="1" Body="&lt;p&gt;There are two processes involved. The first is the formation of any hole, such as erosion of a soft part of the rock, such as flint (silica) forming around something organic, or a softer rock. Also, macrofossils such as tubeworms, gastropods or echinoderms will have a natural cavity to start with. The second process is turbulent (wave driven?) scouring and enlarging of the hole by sand grains. This latter process involves circular eddy-currents which tend to erode an irregular cavity into a rounded cavity. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-27T01:49:52.687" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8274" PostTypeId="1" AcceptedAnswerId="8279" CreationDate="2016-06-27T11:48:54.783" Score="0" ViewCount="128" Body="&lt;p&gt;What does topography mean in topographical barrier? I can't fully understand the word topography. I have read the pages appearing on googling topography.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Topography is the arrangement of the natural and artificial physical features of an area. Could topographical barrier be any landforms like a mountain range,a plateau or even a forest?&lt;/p&gt;&#xA;" OwnerUserId="6215" LastEditorUserId="6215" LastEditDate="2016-06-27T12:15:04.473" LastActivityDate="2016-06-28T05:11:01.533" Title="Topography in general sense" Tags="|terminology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8275" PostTypeId="1" CreationDate="2016-06-27T13:59:10.097" Score="2" ViewCount="246" Body="&lt;p&gt;Most theories suggest that water was already on earth at the beginning but due to temperature most of it evaporated. Others theories suggested that water was brought to earth with komets or asteroids. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But if there was hydrogen available could it be created by combining with the oxygen into H2O?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastActivityDate="2016-06-27T16:04:26.987" Title="Is it possible that water (H2O) was made on earth?" Tags="|atmosphere|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8276" PostTypeId="2" ParentId="8275" CreationDate="2016-06-27T16:04:26.987" Score="6" Body="&lt;p&gt;This is more Astronomy than Earth Science, but the Young Earth, while forming, would have had a hard time retaining Hydrogen.   There's two reasons for this.   One is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Frost_line_(astrophysics)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Frost Line&lt;/a&gt; which means there was relatively little hydrogen and relatively little water and other gases present when the Earth formed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And the other is &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_escape&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atmospheric Escape&lt;/a&gt;.  The Earth doesn't have enough gravity to retain Hydrogen.  In fact, the Earth is still losing Hydrogen, by this &lt;a href=&quot;http://scitechdaily.com/earth-loses-50000-tonnes-of-mass-every-year/&quot; rel=&quot;nofollow noreferrer&quot;&gt;estimate&lt;/a&gt;, about 95,000 tons per year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tcFNO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tcFNO.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Precisely how much hydrogen and water the Earth contained at formation vs how much it acquired by solar wind (Hydrogen nuclei) and comet and asteroid impacts (water and other gases) isn't known.  I think it's likely that the majority came from impacts and I think that's where the consensus leans, but an precise answer isn't known.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as the Earth combining Hydrogen with Oxygen, there's relatively little free Oxygen in the solar-system.  Oxygen binds easily with many elements, so it's abundant but not in it's elemental/gaseous state.  The Earth also tends to lose gaseous hydrogen and not having Oxygen until about 2 billion years ago, it's unlikely that much water was formed in that way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When we learn more about exoplanets, we might find that larger/super Earths might retain more hydrogen and form abundant water in that way if they have photosynthesis to create Oxygen, but that's just theoretical.  Earth is too small to have retained enough hydrogen to do that in large amounts.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2016-06-27T16:04:26.987" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8277" PostTypeId="1" CreationDate="2016-06-28T02:22:07.623" Score="5" ViewCount="499" Body="&lt;p&gt;Recently I've taken an exceptionally unwise interest in the beliefs on conspiracy theorists, in particular flat earthers.  Flat earthism has been trending heavily lately and indeed is undergoing some sort of revival.  Of course, such beliefs run afoul of all scientific disciplines, including geology and geography.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This made me remember of the use of seismic waves to map the core of the earth and also the detection of earthquakes from remote parts of the globe.  These, or course, rely on the true globular nature of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Question:  Are there particularly accessible or convincing accounts of such large scale detectable geologic phenomenon that implicitly rely on the globular geometry of the Earth?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Google would probably suffice but I'm not sure I have the correct terminology.  [My background is in mathematics, in case that would be helpful.]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit:  Let me clarify my request by asking for resources on global seismology which could be effectively presented to someone at college freshman level of education.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6217" LastEditorUserId="595" LastEditDate="2016-06-28T14:10:11.213" LastActivityDate="2018-09-16T15:00:00.120" Title="Global scale seismology experiments / observations disproving flat earth conspiracy?" Tags="|geophysics|seismology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8278" PostTypeId="2" ParentId="8277" CreationDate="2016-06-28T04:57:00.237" Score="3" Body="&lt;p&gt;As you rightly say, seismicity is one geological proof of an almost spherical planet, but surely it is far easier to prove your case by satellite data, such as scenes from &lt;a href=&quot;http://weather.msfc.nasa.gov/GOES/&quot; rel=&quot;nofollow&quot;&gt;http://weather.msfc.nasa.gov/GOES/&lt;/a&gt; Irrespective of the position of the satellite, the Earth always appears as a disc, never 'edge on'. For that matter, if the Earth wasn't approximately spherical there wouldn't be any stable satellite orbits - so no satellite pictures in the first place. You could use your mathematical skills to demonstrate that the only stable orbital configuration is around a sphere. Also the consistency of gravity, at any known point on the planet's surface, points to a spherical Earth. Then there are commercial and military flights which have, over time, flown arcs along almost every conceivable great circle, without ever coming to an edge. Turning to astronomy, every stellar or planetary object large enough to form under gravity appears as a disc - never edge on - surely no coincidence..... etc. etc. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I'm curious - why bother?! You are never going to convince the likes of creationists, climate-change deniers, 'flat earthers', and the like. They have already made up their mind, and don't want to be confused by the facts. No matter how much evidence you supply, it is like water off a duck's back to the closed mind. They are comfortable with their own warped model of reality in their head - no matter how erroneous. Paradoxically, they view the discomfort of having to adjust their world view as a form of 'cognitive dissonance'. So trying to convince flat earthers is like the proverbial 'flogging a dead horse'. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-28T04:57:00.237" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8279" PostTypeId="2" ParentId="8274" CreationDate="2016-06-28T05:11:01.533" Score="2" Body="&lt;p&gt;'Topography' implies variation in altitude. A flat rain forest, such as most of the Amazon basin has very little variation in altitude, and therefore doesn't constitute a topographic barrier. By contrast, the topography of the Andean mountain chain, further west, has a huge altitude variation, and hence constitutes one of the classic topographic barriers in respect of air flow, rainfall, salt balance, etc. &#xA;So any mountain range or plateau may be a topographic barrier. Forests may or may not be topographic barriers, according to whether or not they have significant topographic variation. Hence the forests of Papua New Guinea constitute a t.b., but most lowland forests do not. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-28T05:11:01.533" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8281" PostTypeId="1" CreationDate="2016-06-28T13:42:19.130" Score="1" ViewCount="63" Body="&lt;p&gt;A deepwater circulation had changed direction about 55 million years ago, whereby salt cold water went from north to south. This was seen after research of foraminifera with carbon isotope change.&#xA;But where salt water consist of ions is it also possible that the change of the magnetic field of the earth could cause this change? Or are magnetic fields not of influence on salt water?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="87" LastEditDate="2016-06-28T13:48:55.447" LastActivityDate="2016-06-28T13:48:55.447" Title="Is it possible that a change of the earth magnetic poles influences deep-sea currents?" Tags="|oceanography|paleomagnetism|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8282" PostTypeId="1" CreationDate="2016-06-28T14:09:30.997" Score="2" ViewCount="1212" Body="&lt;p&gt;There is plenty water in the oceans, but I've read that deep in the crust/mantle  of the earth within crystals and other rockforms is water enclosed. So could it be possible that there is more water beneath the surface of the earth than above?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="5372" LastEditDate="2016-06-28T16:51:42.887" LastActivityDate="2016-07-29T00:56:52.743" Title="Is there more water in solid form than in liquid form on earth?" Tags="|water|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8283" PostTypeId="1" CreationDate="2016-06-28T16:57:31.297" Score="2" ViewCount="161" Body="&lt;p&gt;Given a tropical arctic region on a planet like our own, how fast could a cyclone go at the north pole where the Coriolis effect is greatest? In essence: have current cyclones maxed out the wind speeds or is there room to grow at the north pole?&lt;/p&gt;&#xA;" OwnerUserId="6219" LastActivityDate="2017-05-16T07:50:31.823" Title="How Fast Could a Cyclone at the North Pole Achieve?" Tags="|cyclone|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8284" PostTypeId="2" ParentId="8027" CreationDate="2016-06-28T20:01:39.633" Score="5" Body="&lt;p&gt;There's a huge literature on this problem, and depending on who you ask you will get different answers. I'll come at it from the geomorphology perspective.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most uninformative explanation is that sand moves around by the action of water or air. But, how it does so is dependent upon the beach feature/aspect you're trying to describe. Air moves individual grains around by picking them up and carrying them on short trajectories, hops, and collisions with the dry sand bed. Depending on the wind direction, sand is either moved further down the beach, or into the water (or off the beach completely). Windy days are really when this happens. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Water is more complicated. The two dominant processes are alongshore currents and large storm events. Over long times, large areas, and from the birds eye view, shore parallel currents cause the beach to become wider or narrower. These currents are energized by waves and they carry sand along with them. When currents  converge or diverge you have a net gain or loss of sand causing the beach to erode or accrete. For a net gain (accretion), imagine a highway traffic jam: the convergence of cars would be analogous to the a buildup of sand. So sand isn't really being brought in perpendicular to the coastline, instead it's being carried parallel to the beach in the shore parallel current and the traffic-jamming (or the opposite) of the current-carrying sand leads to an accumulation of sand (or net loss). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Storms move massive amounts of sand around, but are really punctuated events (compared to continuous alongshore currents). Waves associated with the storm do drive alongshore currents, and so are subject to the same traffic-jam dynamics mentioned before. But they also move sand around in other ways too. For instance, on barrier islands storms are responsible for the sediment 'over-wash' process, which looks like a tongue/blob of sand extending from the front to the back of the island.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Beach cusps are an interesting feature too (google 'self-organized beach cusps'), but note that the explanation for their formation is debated. Again, it's the water moving sand around, but this is not helpful for describing why a highly repetitious pattern occurs. Personally I believe the only way to explain the dynamics is through the complex-system perspective, which suggests that many of the features you see are 'self-organizing', in short meaning that the sum of the parts (individual grains of sand being moved by water and air) is not equal to the whole (large scale organization). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This all goes to say, we know that water and air move sand around at the scale of individual grains, but how these processes translate to larger scale movements is a difficult problem and is actively being researched. The short answer is, in order to understand how sand is moving around, you have to decide to some extent what feature or aspect of the beach you are interested in, what time scale, and what spatial scale.&lt;/p&gt;&#xA;" OwnerUserId="6221" LastEditorUserId="6221" LastEditDate="2016-07-07T21:00:11.720" LastActivityDate="2016-07-07T21:00:11.720" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8285" PostTypeId="2" ParentId="8215" CreationDate="2016-06-28T20:04:19.773" Score="3" Body="&lt;p&gt;This is the response I received after asking a friend who works as an Hydrologist:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The river is fed by ground water that is slowly leaking out of the base of the mountains. Rain water slowly percolates through the (elevated) soil, which is why the river still runs many months after the rainy season.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Note to other prospective respondents:&lt;/strong&gt; if you have a more technical/accurate answer to my question, I am still curious about the mechanics of this process, and am  will mark yours as the correct answer.&lt;/p&gt;&#xA;" OwnerUserId="6170" LastEditorUserId="6170" LastEditDate="2016-11-27T00:16:51.670" LastActivityDate="2016-11-27T00:16:51.670" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8286" PostTypeId="2" ParentId="8282" CreationDate="2016-06-29T00:18:52.780" Score="2" Body="&lt;p&gt;Clearly you are referring to water locked up in hydrous minerals. The short answer is no, not much water in the Earth at all compared to the surface. The hotter it gets the more hydrous minerals tend to dehydrate, so there are only minuscule traces of water at great depth. I suggest you calculate a rough water balance of water carried into subduction zones = length of subduction zone x thickness x sediment porosity (under pressure) x average subduction rate. This should be compared with estimates of volcanic emission of water vapour (both to the atmosphere and submarine - more difficult to estimate). I'm guessing these should be more or less in equilibrium. The water volume involved is trivial compared to the water on the oceans. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-06-29T00:18:52.780" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8287" PostTypeId="1" CreationDate="2016-06-29T03:44:03.537" Score="2" ViewCount="63" Body="&lt;p&gt;I am trying to find out if there is a way to compute if an earthquake is destructive. I am looking for a threshold formula which depends on magnitude and depth&lt;/p&gt;&#xA;&#xA;&lt;p&gt;for example&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;X = (some constant) * magnitude * depth&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;if &lt;code&gt;X &amp;gt; (some constant)&lt;/code&gt; the earth quake is destructive or secondary effects (landslides, fires, floods or tsunamis) are destructive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This can help in finding out if there is a fixed pattern for the locations of earthquake.&lt;/p&gt;&#xA;" OwnerUserId="6224" LastEditorUserId="2470" LastEditDate="2016-06-29T05:56:36.683" LastActivityDate="2016-06-30T07:26:09.227" Title="Is there a formula to compute the destructiveness of an earthquake?" Tags="|earthquakes|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8288" PostTypeId="1" CreationDate="2016-06-29T03:59:38.730" Score="2" ViewCount="41" Body="&lt;p&gt;I ran the ETERNA code for the prediction of tidal gravity at some station. Then I use Fourier analysis to recover the amplitude and phase of the S2 constituent. As I understand, the phase of the S2 constituent at mid-night is exactly twice the longitude of the station. But from Fourier transform, I always get the phase which is 1 second less.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The code uses UTC time, and the HW95 frequency catalogue. It does include correction from the difference between UTC and UT1 time. But considering this still does not solve my question. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any other sources of modification of the constituent phase in the  code, around 1 second? Thank you in advance!&lt;/p&gt;&#xA;" OwnerUserId="6225" LastActivityDate="2016-06-29T03:59:38.730" Title="Phase of S2 constituent in tidal prediction" Tags="|geophysics|tides|gravity|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8289" PostTypeId="2" ParentId="8287" CreationDate="2016-06-29T09:23:09.817" Score="1" Body="&lt;p&gt;The 'destructiveness' is a function of local geology and hydrogeology, type of earthquake, depth of earthquake, local population density, and whether the local builders paid attention to the appropriate building codes. So no, there isn't an equation for destructiveness. However, you can estimate the local intensity (at the surface) from the magnitude. The mathematical approach is given in the &lt;a href=&quot;http://www.sosmath.com/algebra/logs/log5/log56/log56.html&quot; rel=&quot;nofollow&quot;&gt;APPLICATIONS OF EXPONENTIAL AND LOGARITHMIC FUNCTIONS&lt;/a&gt; for earthquakes.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="6093" LastEditDate="2016-06-30T07:26:09.227" LastActivityDate="2016-06-30T07:26:09.227" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8290" PostTypeId="1" CreationDate="2016-06-29T12:22:15.010" Score="6" ViewCount="820" Body="&lt;p&gt;I've heard that during the accretion of proto-planets that formed the earth, 60 minerals were created through the reactions of atoms and molecules in the nebula.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do these first minerals still make up Earth?&lt;br&gt;&#xA;Do we have more minerals? If so, how and when were they created? &lt;/p&gt;&#xA;" OwnerUserId="5923" LastEditorUserId="725" LastEditDate="2016-07-06T11:52:00.590" LastActivityDate="2016-07-06T12:00:17.910" Title="Were all of Earth's minerals created before Earth's formation, during, or after?" Tags="|geology|earth-history|minerals|planetary-formation|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8291" PostTypeId="1" CreationDate="2016-06-29T13:40:11.337" Score="3" ViewCount="254" Body="&lt;p&gt;In big clouds of water vapor their could raise a difference in charges high and low in the clouds but is it necessary that there are clouds? Could there be lightning just with airstreams which create lightning? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sometimes they say that life began in a mixture of liquids like methane hydrogen and ammonia together with lightning. But in the beginning of the earthlife were there already clouds to form lightning?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="64" LastEditDate="2016-07-04T15:44:47.317" LastActivityDate="2016-07-06T10:43:30.630" Title="Are clouds needed for lightning?" Tags="|meteorology|lightning|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8292" PostTypeId="2" ParentId="8290" CreationDate="2016-06-29T13:54:36.517" Score="1" Body="&lt;p&gt;Minerals are naturally occurring chemical compounds composed of elements. Much of these elements were originally deposited with the earth saw formed. However, meteorites and asteroids have carried new mass onto the earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is true some elements are too heavy to have been created by the Sun's fusion process. These heavier elements would have been created by other processes like various types of cosmic explosions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mineral creation is an ongoing process on the earth.  So mineral creation is happening today.  One example would be volcanic vents at the sea floor creating metal sulfide minerals like ZnS - sphalerite and PbS Galena.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth processes are constantly reworking existing rocks and minerals.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Copper Porphyry deposits have a igneous intrusion and the fluids from the intrusion flow into surrounding rock dissolving and redepositing minerals, creating a super-gene enrichment zone.  At the deposit in Tsuemb Africa, a secondary super-gene enrichment zone was created by faults carrying surface water downward into the deposit.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2016-06-29T13:54:36.517" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8293" PostTypeId="1" CreationDate="2016-06-29T15:35:42.613" Score="4" ViewCount="4056" Body="&lt;p&gt;Usually when I think of a lake it should be sweet water as all the water is coming from rivers/mountains and rain and, because it is very low situated, all ground water should also flow into it. &#xA;But the Dead Sea is very salty (32%). So how did all that salt came into that lake?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, why is it called a sea and not a lake?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="20" LastEditDate="2016-07-08T16:17:27.857" LastActivityDate="2016-07-08T16:17:27.857" Title="Where does all the salt come from in the Dead Sea?" Tags="|water|salinity|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8294" PostTypeId="2" ParentId="708" CreationDate="2016-06-29T15:44:20.563" Score="1" Body="&lt;p&gt;The primary reason behind the occurrence of this positive feedback is in the radiative properties of high and low clouds.&#xA;According to the Stefan–Boltzmann law, the total radiant heat energy emitted from a surface is proportional to the fourth power of its absolute temperature.&#xA;While the change in altitude changes the optical properties of the clouds, meaning, there is an increased transmittance of shortwave radiation coming from the sun toward the Earth's surface, there is also a decrease in the re-emission of the absorbed longwave radiation being emitted from the earth's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To summarize, higher clouds let more sunlight pass through them. They absorb earth's emissions but let out decreasing amounts with decrease in their temperature.&lt;/p&gt;&#xA;" OwnerUserId="552" LastActivityDate="2016-06-29T15:44:20.563" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8295" PostTypeId="2" ParentId="8283" CreationDate="2016-06-29T17:44:47.913" Score="4" Body="&lt;p&gt;There's a few problems with this question.  The first is, the Coriolis effect isn't a force in and of itself.  It's a velocity dependent effect.   If the wind speed is zero over the North or South Pole, the Coriolis effect would be zero.    If the wind speed is 100 kph over the pole, the Coriolis force would be (if this site is &lt;a href=&quot;http://profhorn.meteor.wisc.edu/wxwise/museum/a10/a10coriolis.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;trustworthy&lt;/a&gt;) $0.000146 \times V \times \sin(latitude)$, in other words, pretty small, but over long distances, a small force can create a significant change in direction.   But there-in lies the problem to answering your question.   It would depend on the size of the cyclone and the initial wind speed of the cyclone. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other problem is, the Coriolis force doesn't form neat little circles.  Around the polls it's more like this, so estimating a presumably circular cycolone entirely due to Coriolis is doubly problematic, because a cyclone wouldn't form.  You'd get some wind direction change but not a cyclone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZDLT2.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZDLT2.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cyclone effect is the most efficient way to move air, as lower mass warm air wants to rise to higher altitudes and higher mass cold air wants to fall to lower altitudes.  The cyclone may be initiated by the Coriolis effect but once begun, it's driven by warm water, evaporation, and variation in air mass.  If you notice, Cyclones lose strength both on land and if they turn north over the ocean.  The colder ocean reduces the wind strength because it evaporates less easily and the air over the ocean cools, so with real cyclones, as the Coriolis effect grows stronger as the cyclone moves north, the cyclone grows weaker.  Cyclones don't represent the Coriolis effect.  It only plays a role in getting them started.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you probably know, the Coriolis effect doesn't actually move anything.  Objects move by their momentum and the Earth rotates by it's momentum and it's the earth that moves under the object that gives the impression of a Coriolis effect.   If you stand on the North Pole, the Earth rotates about about 1/2 the speed of the hour hand on your watch.   It's hard to imagine that has much effect on anything and it doesn't unless the distance is significantly large.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can't do the precise math on this one, though I find it quite interesting, but the above is a general answer.   If you try the physics board, you might get a more mathematical answer, but I think the question might work better with a bowling ball and a friction-less earth rather than the wind and the earth and a cyclone of unspecified size.   I got curious, so I asked the question &lt;a href=&quot;https://physics.stackexchange.com/questions/265374/if-we-assume-a-perfectly-spherical-and-frictionless-earth-and-we-bowl-a-bowling?noredirect=1#comment588774_265374&quot;&gt;with that in mind&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="725" LastEditDate="2017-05-16T07:50:31.823" LastActivityDate="2017-05-16T07:50:31.823" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8296" PostTypeId="2" ParentId="8267" CreationDate="2016-06-29T18:19:07.640" Score="6" Body="&lt;p&gt;Your image looks very similar to rocks we get here on the West Coast of Vancouver Island.  We have some rock boring bivalves that will effectively drill into the rock which breaks off and erodes into a shape similar to what you are showing.  &lt;a href=&quot;https://en.wikipedia.org/wiki/Pholadidae&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Pholadidae&lt;/a&gt; or &lt;a href=&quot;https://the-hazel-tree.com/2013/08/21/piddocks-anything-but-boring/&quot; rel=&quot;noreferrer&quot;&gt;https://the-hazel-tree.com/2013/08/21/piddocks-anything-but-boring/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are also echinoderms that will bore into rocks, Strongylocentrotus purpuratus, &lt;a href=&quot;https://en.wikipedia.org/wiki/Strongylocentrotus_purpuratus&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Strongylocentrotus_purpuratus&lt;/a&gt; &#xA;&lt;a href=&quot;https://bmscblog.wordpress.com/2013/01/09/holey-rocks/&quot; rel=&quot;noreferrer&quot;&gt;https://bmscblog.wordpress.com/2013/01/09/holey-rocks/&lt;/a&gt;  but the holes from these creatures tend to be larger than the image you present.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I a confident that the holes are created by some form a boring bivalve.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastEditorDisplayName="user824" LastEditDate="2016-06-29T20:29:02.477" LastActivityDate="2016-06-29T20:29:02.477" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8297" PostTypeId="2" ParentId="8293" CreationDate="2016-06-29T18:45:08.650" Score="4" Body="&lt;p&gt;The difference between a lake and sea can simply be size and what humans desire to call it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can think of the Dead Sea as a giant lake if you wish.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The salt in the seas comes from rain running on top of rocks, such as mountains, and carrying the minerals, which contain salt, with them into the sea. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In rivers, the water runs continuously and the minerals are carried away into the open ocean (which is why the sea is salty).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In closed lakes, like the Dead Sea, the water can not escape into the ocean and the minerals/salt build up. &lt;/p&gt;&#xA;" OwnerUserId="5923" LastActivityDate="2016-06-29T18:45:08.650" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8298" PostTypeId="1" CreationDate="2016-06-29T18:53:20.400" Score="3" ViewCount="381" Body="&lt;p&gt;In the attached topographical map, you can see some strong topographic features in Northern California — elongated foothills below Mt. Tamalpais.  You can also see, circled, some apparent anomalies.  What could account for them?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7rMqu.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7rMqu.png&quot; alt=&quot;Topographical map of the area east of Mt. Tamalpais&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4611" LastEditorUserId="725" LastEditDate="2017-05-16T07:46:25.373" LastActivityDate="2017-06-20T21:10:31.347" Title="What processes created these apparent topographical anomalies in North California?" Tags="|geomorphology|topography|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8299" PostTypeId="1" AcceptedAnswerId="8300" CreationDate="2016-06-29T19:03:51.020" Score="4" ViewCount="941" Body="&lt;p&gt;The air is composed of mainly nitrogen.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, when you feel wind, is it mainly nitrogen particles hitting you that, on average, are moving in one direction? &lt;/p&gt;&#xA;" OwnerUserId="5923" LastActivityDate="2017-05-16T14:50:09.560" Title="Is wind just mainly nitrogen particles moving in one direction?" Tags="|meteorology|atmosphere|wind|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8300" PostTypeId="2" ParentId="8299" CreationDate="2016-06-29T22:25:50.930" Score="4" Body="&lt;h2&gt;Composition of gases forming air&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The air around us consists of approximately 78% gaseous $\ce{N2}$ (gaseous nitrogen) by volume. When we assume that all atmospheric gases are ideal gases then 78 of 100 gaseous molecules, which hit us, are $\ce{N2}$ molecules.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Distinguishing between particles and gases&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;However, we have gaseous and particulate compounds in the atmosphere. $\ce{N2}$, $\ce{O2}$, $\ce{NO}$, $\ce{NO2}$, and $\ce{SO2}$ are gaseous compounds in the atmosphere. We also have particles in the atmosphere. Such as pure ammonium sulfate ($\ce{\left(NH4^+\right)_2SO4^2-}$) particles, sea salt particles (consisting of dominantly $\ce{NaCl}$ and $\ce{Na2SO4}$), organic particles, or soot.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When we talk about the composition of the air, we usually mean the gaseous compounds and not the particulate compounds.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Nitrogen at/in particles&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;We have gaseous $\ce{NH3}$ (ammonia) and $\ce{HNO3}$ (nitric acid) in the atmosphere. The first is primarily emitted from processed faeces. In Europe the intensive animal farming is a major source for $\ce{NH3}$ emissions. The latter is a reaction product of $\ce{NO2}$ (emitted by combustion processes) and $\ce{OH}$ ($\ce{OH}$ radicals). These two compounds condense on particles or form new particles as $\ce{NH4^+NO3^-}$, with sulfate ($\ce{\left(NH_4^+\right)_2SO_4^{2-}}$), or on sea salt particles as $\ce{NaNO3^-}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When we are in regions with high anthropogenic emissions by animal farming and industry/transportation, such as Northwestern Europe, Eastern China, or US Coast, we also have these nitrogen compounds in the air. They for new particles or condense on existing particles. Therefore, &lt;em&gt;many&lt;/em&gt; particles in these regions are nitrogen-containing particles.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Number of particle and molecules&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;How much particles do we have in a $m^3$ of air/aerosol?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, &lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1240270/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Penttinen et al. (2001)&lt;/a&gt; published a number of about 15000 particles per $cm^3$ (measurement in polluted air; commonly the number concentrations are lower). These are $1.5 \times 10^4\ cm^{-3}$ or $1.5\times 10^{10}\ m^{-3}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;\begin{align}&#xA; &amp;amp; 1\ m = 100\ cm  \\&#xA;\Rightarrow &amp;amp; 1\ m^3 = \left(100\ cm\right)^3 = 1000000\ cm^3 = 10^6\ cm^3 \\&#xA;\Leftrightarrow &amp;amp; 1\ m^{-3} = 10^{-6}\ cm^{-3} \\&#xA;\Leftrightarrow &amp;amp; 10^6\ m^{-3} = 1\ cm^{-3} \\&#xA;\Rightarrow &amp;amp; 1.5\times 10^4\ cm^{-3} = 1.5\times 10^4\times 10^6\ m^{-3} = 1.5\times 10^{10}\ m^{-3}&#xA;\end{align}&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How much gaseous molescules? Assuming a standard pressure $p$ of 101325 Pa, a temperature $T$ of 293 K (20 degree C) we have:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\frac{n}{V} = \frac{p}{R\times T} = \frac{101325\ Pa}{8.314\ J\ K^{-1}\ mol^{-1} \times 293\ K} \approx 41.59\ \frac{mol}{m^3} \approx 2.5 \times 10^{25}\ \frac{molecules}{m^3}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$R$ is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Gas_constant&quot; rel=&quot;nofollow noreferrer&quot;&gt;gas constant&lt;/a&gt;, $n$ is the particle number in moles, and $V$ is the volume. The conversion from moles to &lt;em&gt;number of molecules&lt;/em&gt; is performed via the &lt;a href=&quot;https://en.wikipedia.org/wiki/Avogadro_constant&quot; rel=&quot;nofollow noreferrer&quot;&gt;Avogadro constant&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We have in the order of $10^{10}$ particles and in the order of $10^{25}$ molecules per $m^3$. Hence, we are are dominantly hit by gaseous molecules (assuming equal speed of particles and moolecules which is not necessarily correct).&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Answer&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;No, we are not mainly hit by nitrogen particles. However, we are mainly hit by nitrogen molecules. &lt;/p&gt;&#xA;" OwnerUserId="5594" LastEditorUserId="5594" LastEditDate="2017-05-16T14:50:09.560" LastActivityDate="2017-05-16T14:50:09.560" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8302" PostTypeId="2" ParentId="8299" CreationDate="2016-06-29T22:54:16.073" Score="6" Body="&lt;p&gt;In a nutshell, you're a little bit right.  The Air pressure is essentially Nitrogen and Oxygen molecules hitting our bodies, but that's true with and without wind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;wind is more easily explained from the macro-scale not the micro-scale.  It's not molecular behavior but governed by forces like high and low pressure systems and weather, or, fans if you're indoors. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Brownian_motion&quot; rel=&quot;noreferrer&quot;&gt;The Brownian&lt;/a&gt; motion of molecules is pretty consistent like 3d billiard balls, though velocity of the molecules increases with temperature.  This is kind of what air molecules movement looks like:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BAEQ9.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BAEQ9.gif&quot; alt=&quot;https://upload.wikimedia.org/wikipedia/commons/6/6d/Translational_motion.gif&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wind is, in a nutshell, the entire box moving, not individual particles changing direction, but it could probably be looked at either way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If all the air molecules, by some strange coincidence, all moved in the same direction 2 things would happen.  One, the air would get very cold as temperature is essentially agitated molecules moving or vibrating against each other, and two, the wind speed would be over 1000 kph.  Roughly the speed of sound.   Fortunately this kind of thing is so statistically improbable it essentially never happens.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2016-06-29T22:54:16.073" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8304" PostTypeId="1" CreationDate="2016-06-30T05:16:28.630" Score="0" ViewCount="191" Body="&lt;p&gt;Following a mobilista approach over geological time, and considering the Earth's internal heat as responsible for tectonic regime, which was involved in the &quot;Permobile type&quot; during the early times of the Archean, what would be the pedogenesis in this context?&lt;/p&gt;&#xA;" OwnerUserId="5920" LastActivityDate="2016-07-01T01:02:40.640" Title="There is soil in Archean?" Tags="|geology|atmosphere|stratigraphy|precambrian|research|" AnswerCount="1" CommentCount="1" ClosedDate="2016-07-01T17:39:24.140" ContentLicense="CC BY-SA 3.0" />
  <row Id="8305" PostTypeId="1" CreationDate="2016-06-30T07:52:49.007" Score="4" ViewCount="150" Body="&lt;p&gt;&lt;a href=&quot;http://news.nationalgeographic.com/news/2009/07/090731-green-sahara.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article of desert greening&lt;/a&gt; states that some areas around the Sahara have seen increased plant growth in recent decades, caused by global warming. The causal chain would be warmer air can hold more water -&gt; more precipitation -&gt; more plant growth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apparently (from historical sources) the Sahara was wetter during the medieval climate anomaly, which would fit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the article gives as sources satellite images, reports by locals on plant growth and climate models predicting increased precipitation. Which makes me wonder, isn't there direct measurement of precipitation in some relevant areas (over the last decades)? Don't we have direct data to check?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Helpful would be data from the areas indicated in the article: Sahel zone, central Chad, Western Sudan.&lt;/p&gt;&#xA;" OwnerUserId="117" LastEditorUserId="1109" LastEditDate="2016-12-20T10:23:16.013" LastActivityDate="2016-12-20T10:23:16.013" Title="Desert greening - Do we have long term (several decades) data on precipitation around the Sahara?" Tags="|climate-change|measurements|rainfall|desert|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8306" PostTypeId="1" CreationDate="2016-06-30T13:15:53.397" Score="4" ViewCount="4682" Body="&lt;p&gt;I have been trying to find data of sea temperatures in the deep sea (&gt;1000 m), but I still haven't found any scientific papers. I have only seen websites talking about the temperatures, but without providing evidence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what's the evidence for very low (&amp;lt;10&amp;deg;C) temperatures in the deep sea and what were the methods used to obtain this evidence?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know about the websites like &lt;a href=&quot;https://www.nodc.noaa.gov/cgi-bin/OC5/SELECT/woaselect.pl&quot; rel=&quot;nofollow&quot;&gt;https://www.nodc.noaa.gov/cgi-bin/OC5/SELECT/woaselect.pl&lt;/a&gt; where I can check the temperature, I'm foremost asking for the methodology.&lt;/p&gt;&#xA;" OwnerUserId="6232" LastEditorUserId="111" LastEditDate="2016-07-06T17:55:00.867" LastActivityDate="2016-07-06T17:55:00.867" Title="The temperature of the ocean below 1000 m" Tags="|ocean|oceanography|temperature|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8307" PostTypeId="1" CreationDate="2016-06-30T14:59:51.063" Score="3" ViewCount="56" Body="&lt;p&gt;I have detrital mica separates that I would like to mount in EpoThin resin for microprobe analysis and I would simply like to know the best method for mounting them. With zircons you can mount on double sided tape and then simply pour the resin over them. But with micas I am worried that they will not peel away easily from the tape once the resin has cured. I am also concerned about polishing them. Any advice would be much appreciated. &lt;/p&gt;&#xA;" OwnerUserId="6083" LastActivityDate="2016-07-06T13:18:50.997" Title="What is the best way to mount white mica separates?" Tags="|geology|sedimentology|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8308" PostTypeId="2" ParentId="8306" CreationDate="2016-06-30T15:16:26.407" Score="3" Body="&lt;h2&gt;General Information&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;One major operational system for the measurement of deep sea temperature, salinity and pressure is the Argo program. Individual Argo floats are distributed in the worlds oceans. Their measurement data are scientifically evaluated and are available for public download. Additionally, several research institutions own gliders. However, I am not sure if they are also used operational for deep sea measurements.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Argo floats&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Argo_(oceanography)&quot; rel=&quot;nofollow&quot;&gt;Argo floats&lt;/a&gt; are large submerged buoys. They are made for profiling the top 2000 m of the world's oceans. The common depth of an Argo floater is approximately 1000 m. Approximately in 10-day intervals they sink to 2000 m depth and afterwards rise to the sea surface, from where broadcast their position and measurement data. Currently, more than 1000 Argo floats are active in the worlds oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The official Argo homepage is &lt;a href=&quot;http://www.argo.net/&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;. &lt;a href=&quot;http://www.argo.ucsd.edu/How_Argo_floats.html&quot; rel=&quot;nofollow&quot;&gt;Here&lt;/a&gt; you find a more detailed description of the function of Argo drifters and &lt;a href=&quot;http://www.argo.net/TXTdata.html&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt; you can download drifter measurements.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Gliders&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Underwater_glider&quot; rel=&quot;nofollow&quot;&gt;Gliders&lt;/a&gt; are one tool for measuring temperature and salinity on vertical transects (actually not a purely vertical transect). Some gliders can go below 1000 m. The disadvantage of a glider is that it needs considerable horizontal space available straight ahead of his direction of motion. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A nice explanation and applications are given &lt;a href=&quot;http://www.hzg.de/institutes_platforms/cosyna/index.php.en&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;http://spray.ucsd.edu/pub/rel/info/spray_description.php&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.ego-network.org/dokuwiki/doku.php&quot; rel=&quot;nofollow&quot;&gt;This&lt;/a&gt; is the homepage of the global scientific glider community.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2016-06-30T15:16:26.407" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8309" PostTypeId="2" ParentId="8306" CreationDate="2016-06-30T15:33:36.303" Score="3" Body="&lt;p&gt;There is a lot of information about temperature bellow 100m and it comes from a variety of sources. Just in the World Ocean Database (&lt;a href=&quot;https://www.nodc.noaa.gov/OC5/WOD13/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nodc.noaa.gov/OC5/WOD13/&lt;/a&gt;) you will find a variety of sources (e.g., XBT, CTD...).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can download the original data that goes into the temperature fields from: &lt;a href=&quot;https://www.nodc.noaa.gov/cgi-bin/OC5/wod13/getgeodata.pl?Depth=O&amp;amp;WorldOcean.x=612&amp;amp;WorldOcean.y=192&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nodc.noaa.gov/cgi-bin/OC5/wod13/getgeodata.pl?Depth=O&amp;amp;WorldOcean.x=612&amp;amp;WorldOcean.y=192&lt;/a&gt;. The data includes:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Nansen_bottle&quot; rel=&quot;nofollow noreferrer&quot;&gt;Niskin Bottles&lt;/a&gt;: they have been used for decades (the precursor Nansen bottles were developed in 1910) to collect samples of seawater at specific depths. Currently, they are not used that much for temperature as a number of corrections are needed to compensate for the change in pressure, but they are still used for other variables (e.g., chemical and biological analyses).&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/CTD_(instrument)&quot; rel=&quot;nofollow noreferrer&quot;&gt;CTD&lt;/a&gt;: High resolution Conductivity Temperature Depth sensors use conductivity to determine water temperature (and salinity). They sample much faster and are the standard for temperature sampling.  &lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Bathythermograph#Expendable_Bathythermograph&quot; rel=&quot;nofollow noreferrer&quot;&gt;XBT&lt;/a&gt;: Expendable bathythermograph have been used since the 1960s and are much cheaper to deploy. They are not that great as deep water sensors as biases are introduced. &lt;/li&gt;&#xA;&lt;li&gt;Profiling float data such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Argo_(oceanography)&quot; rel=&quot;nofollow noreferrer&quot;&gt;ARGO&lt;/a&gt;: They are currently the standard way to measure temperature in the ocean. ARGO has been around since around 2003. The profiling floats drift at (usually) 1000m and every 10 days (usually) dive to a depth of 2000 meters (or even deeper in some cases) and sample  conductivity and temperature from there to the surface. From there they send the data to a satellite and then go down to 1000m again.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;There are a lot of publications that use the global temperature data. Documentation of the entire database is provided by &lt;a href=&quot;http://data.nodc.noaa.gov/woa/WOD/DOC/wod_intro.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good representation of the temperature in the deep ocean can be seen in this North-South section. &lt;a href=&quot;https://i.stack.imgur.com/rugfb.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rugfb.png&quot; alt=&quot;North-south temperature section&quot;&gt;&lt;/a&gt; All the small points are observations. You can see the colder temperatures in the deep South Atlantic associated with the &lt;a href=&quot;https://en.wikipedia.org/wiki/Antarctic_Bottom_Water&quot; rel=&quot;nofollow noreferrer&quot;&gt;Antarctic Bottom Water&lt;/a&gt; versus the temperatures on the deep North Atlantic from the &lt;a href=&quot;https://en.wikipedia.org/wiki/North_Atlantic_Deep_Water&quot; rel=&quot;nofollow noreferrer&quot;&gt;North Atlantic Deep Water&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2016-07-02T12:40:39.127" LastActivityDate="2016-07-02T12:40:39.127" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8310" PostTypeId="2" ParentId="8304" CreationDate="2016-07-01T01:02:40.640" Score="3" Body="&lt;p&gt;I don't totally understand what you are asking but yes there was soil in the Archean. In some locations around the world, these soils were buried and preserved as paleosols. The Archean paleosols are very important in studying the origin of the atmosphere because the oxidation state of the minerals is an indicator of the presence or absence oxygen and other gases in the atmosphere (&lt;a href=&quot;http://geology.gsapubs.org/content/early/2014/08/28/G36091.1.abstract&quot; rel=&quot;nofollow&quot;&gt;Mukhopadhyay et al., 2014&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2016-07-01T01:02:40.640" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8311" PostTypeId="1" CreationDate="2016-07-01T09:38:38.277" Score="3" ViewCount="359" Body="&lt;p&gt;Almost all the theories that explain the origin of Earth says, it was way hot back then. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That means It was in a lava state in its early days. Then gradually cooled down to the current state. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this is the case how did the earth retain this much of water on its surface? &lt;/p&gt;&#xA;" OwnerUserId="6239" LastEditorUserId="5320" LastEditDate="2016-07-03T08:55:38.717" LastActivityDate="2016-07-05T17:11:59.993" Title="How does water still exist on the Earth?" Tags="|oceanography|earth-history|planetary-science|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8312" PostTypeId="2" ParentId="8306" CreationDate="2016-07-01T10:18:48.983" Score="1" Body="&lt;p&gt;Thanks @daniel.neuman, I have looked up some profiles to get some data:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here we see Sea temperature data as measured by the Argo project buoys on the x-axis as function of the pressure in decibars on the y-axis.&lt;br&gt;&#xA;Note that decibars correspond to metres as one delves into water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I took the data for a period of 1st until 10th of June 2016 (this is one full cycle of the Argo buoys), longitudinally over the whole globe, latitudinally between 60°N and 90°N.&lt;br&gt;&#xA;Thus this data includes streams from the arctic (as seen in the colder curves) and the mid-latitudes (the warmer curves). I have checked the other latitudes, between 60°S and 60°N, they essentially look similar to the warm curves seen in here.&lt;br&gt;&#xA;Between 90°S and 60°S they look similar, but suprisingly a bit warmer than on the northern hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/X1fjH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/X1fjH.png&quot; alt=&quot;(c) The Argo project&quot;&gt;&lt;/a&gt;&#xA;(c) The Argo project&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="489" LastEditDate="2016-07-01T15:07:49.057" LastActivityDate="2016-07-01T15:07:49.057" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8313" PostTypeId="2" ParentId="8293" CreationDate="2016-07-01T11:55:13.143" Score="7" Body="&lt;p&gt;The composition of the Dead Sea is quite unlike most other salt lakes, and is not at all like sea-water. Compare the concentrations, in grams per litre:&#xA;&lt;img src=&quot;https://i.stack.imgur.com/YmKOk.png&quot; width=&quot;300&quot; &gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The potassium, bromine and magnesium are all hugely enriched relative to seawater, so clearly, it is not just a case of evaporation of residual seawater from the time of isolation of the Dead Sea. In fact, the vast majority of the water, and almost all of the magnesium, is derived from rivers draining from the north, from around the sea of Galilee, where magnesium-rich volcanic rocks weather rapidly. Much of the sodium and chlorine is derived from evaporation of rainfall originating from the Mediterranean - rainfall being just massively diluted sea water to start with. The high calcium and potassium comes from evaporite dissolution from the surrounding and adjacent rocks, especially from the Lissan Marl and saline springs emanating therefrom.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The real problem is: Where did all that bromine come from? The Dead Sea has the highest concentration of bromine in the world, and it is far from obvious how it got there. Clearly, there has been a massive concentration process. Maybe it was concentrated in the saline base of a much larger lake during the time of formation of the crustal formation of the Aqaba - Dead Sea - Gollan Heights rift? Any 'armchair theorists' out there with a better hypothesis? &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="100" LastEditDate="2016-07-01T12:26:25.433" LastActivityDate="2016-07-01T12:26:25.433" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8314" PostTypeId="2" ParentId="8293" CreationDate="2016-07-01T12:30:55.533" Score="2" Body="&lt;p&gt;I'll add a bit about the name:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Biblical Hebrew (and to a large degree in modern Hebrew), the word for sea is &quot;yam&quot; (ים), which doesn't have the modern meaning of a roughly defined area that is part of the larger ocean system. Instead, it basically means &quot;a large body of water&quot;. There four &quot;seas&quot; in this region. &quot;Yam Hamelah/Hamavet&quot; (&quot;sea of the salt/dead&quot; ים המלח/מוות), &quot;Yam Kinneret&quot; (sea of galilee ים כינרת), &quot;Yam&#xA;Soof/Hayam Ha'adom&quot; (sea of reed/the Red Sea ים סוף/הים האגום) and just &quot;Yama&quot; (&quot;to the sea&quot; ימה), literally means &quot;west&quot;, referring to the Mediterranean Sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The word for lake, &quot;agam&quot; (אגם), was used only for small seasonal ponds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The biblical usage for the &quot;seas&quot; remained in modern Hebrew, but whenever we refer to any other inland bodies of water elsewhere in the world, we actually use &quot;agam&quot; and not &quot;yam&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in summary, it's called a sea because of historical and linguistic reasons, not because of any geographical or morphological features.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-07-01T12:30:55.533" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8315" PostTypeId="1" CreationDate="2016-07-01T13:18:07.090" Score="3" ViewCount="196" Body="&lt;p&gt;Salt water of the oceans could freeze into ice at a temperature of -1,8C. Now there is a lot ice on the poles but of all the floating ice how much is that a grown in and of the water itself?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With other words, is the current of the ocean waters an obstacle for creating ice or is there a minimum temperature at which water in each case will turn into ice independent of currentstreams and is this temperature reached in the articpoles?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I'm not asking about snow what is pressed into ice on the poles.&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="111" LastEditDate="2016-07-01T14:34:42.250" LastActivityDate="2017-05-16T07:35:44.083" Title="Is ice also created ín cold water of the oceans?" Tags="|ocean|water|sea-ice|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8317" PostTypeId="1" AcceptedAnswerId="8340" CreationDate="2016-07-01T17:24:25.233" Score="3" ViewCount="593" Body="&lt;p&gt;I’m conducting an independent study as a concerned citizen on the indoor temperature at an animal shelter to support the need of improved air conditioning by documenting how hot it can reach during summer that would exceed veterinary standards. I’ve bought an electronic hygrometer and have also obtained the building floor plans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;My current data collection process would be the following:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;conduct measurements during a high temperature, high humidity, and low cloud cover day.&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;best mimics the extreme conditions that the animals would be exposed to.&lt;/li&gt;&#xA;&lt;li&gt;record the date/time and measure or record current outdoor conditions: &#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;temp (shade and direct sun), relative humidity, cloud cover, wind speed.&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;record the current facility’s AC temperature setting.&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;take relative humidity (RH) and temperature measurements throughout the facility at 5ft spacing.&#xA;&lt;em&gt;(Please advise if my distance is too large or too small)&lt;/em&gt;&lt;/li&gt;&#xA;&lt;li&gt;gently wave hygrometer from side to side for approximately 15 seconds to adjust sensors to current position’s environment.&lt;/li&gt;&#xA;&lt;li&gt;take all indoor measurements from a 1ft height (approximate mid-height of a dog) using a pole.&lt;/li&gt;&#xA;&lt;li&gt;take measurements from one end of the facility and walk forwards/sideways in a grid pattern to prevent my body heat and humidity from influencing the reading, and also to limit air circulation from my movements.&lt;/li&gt;&#xA;&lt;li&gt;wear latex gloves so hand sweat does not increase the RH value.&lt;/li&gt;&#xA;&lt;li&gt;take measurements within each animal enclosure as there will be additional humidity from water&#xA;bowls, urine, etc.&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;this would be done after the main isles are measured to reduce air movement from opening and closing the enclosures from influencing the aisle measurements.&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;mark each measurement point on the floor plan and log the data in a spreadsheet.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;My data analysis will consist of the following:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;floor plan heat map overlays for the following:&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;air temperature&lt;/li&gt;&#xA;&lt;li&gt;relative humidity&lt;/li&gt;&#xA;&lt;li&gt;heat index (HI)&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;calculate the following values:&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;animal enclosures&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;average/min/max temperature&lt;/li&gt;&#xA;&lt;li&gt;average/min/max RH&lt;/li&gt;&#xA;&lt;li&gt;average/min/max HI&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;shelter facility&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;average/min/max temperature&lt;/li&gt;&#xA;&lt;li&gt;average/min/max RH&lt;/li&gt;&#xA;&lt;li&gt;average/min/max HI&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Am I missing anything that could potentially invalidate my results and result in inaccurate measurements, or am I lacking any specific data which I should be collecting or calculating? I want this to be as accurate as possible and provide credible evidence that current conditions are not within veterinary standards.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;I had asked if this type of question was on-topic &lt;a href=&quot;https://earthscience.meta.stackexchange.com/questions/1552/is-asking-a-question-on-proper-temperature-humidity-measuring-on-topic/1553#1553&quot;&gt;here&lt;/a&gt;, but overall if it is not please do not close it. Just leave a comment and I'll delete it so as not to ding me negatively in the system. Thank you.&lt;/p&gt;&#xA;" OwnerUserId="6235" LastEditorUserId="-1" LastEditDate="2017-03-16T16:41:57.373" LastActivityDate="2016-07-04T20:48:04.783" Title="Accurately Measuring Indoor/Outdoor Air Temperature &amp; Relative Humidity" Tags="|temperature|measurements|humidity|data-analysis|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8318" PostTypeId="1" CreationDate="2016-07-01T21:21:22.203" Score="4" ViewCount="368" Body="&lt;p&gt;According to the FAA's &lt;a href=&quot;http://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_00-45G_CHG_1-2.pdf#page=102&quot; rel=&quot;nofollow&quot;&gt;Aviation Weather Services&lt;/a&gt; advisory circular,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Values below 15 dBZ are typically associated with clouds. However, they may also be&#xA;  caused by atmospheric particulate matter such as dust, insects, pollen, or other phenomena.&#xA;  &lt;strong&gt;The scale cannot be used to determine the intensity of snowfall.&lt;/strong&gt; However, snowfall rates&#xA;  generally increase with increasing reflectivity.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Why can't that scale be used to determine the intensity of snowfall?&lt;/p&gt;&#xA;" OwnerUserId="6242" LastActivityDate="2020-03-08T13:03:02.457" Title="Why can't radar's decibel scale be used to determine the intensity of snowfall?" Tags="|snow|radar|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8319" PostTypeId="2" ParentId="8318" CreationDate="2016-07-01T21:56:10.880" Score="5" Body="&lt;p&gt;Snow, unlike rain, has holes as well as different refractive properties. This allows the radar beam to penetrate and reflect the beam differently than an ordinarily oblate rain drop.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2016-07-01T21:56:10.880" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8321" PostTypeId="2" ParentId="8315" CreationDate="2016-07-02T07:01:02.250" Score="5" Body="&lt;p&gt;The &lt;a href=&quot;https://nsidc.org/cryosphere/seaice/characteristics/formation.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Snow and Ice Data Center website&lt;/a&gt; describes the process of ice formation on polar oceans. Virtually all of the young ice is made from ocean water which retains some brine in the process of forming. Older ice tends to lose the brine and have it replaced by air bubbles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Surface ice would form differently, either by frost, which tends to form in patterns or in snow fall.  Over many years it might be possible for snowfall and surface forming ice to build up on top of permanent ocean ice. I'm not sure what the ratio could eventually become, but if sea ice was to be mostly from the air, it would need to be very old where over time, enough ice formed on top and the original ice melted from the bottom.  On average I suspect most sea ice is ocean ice though, even multi-year ice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When temperatures are low enough (below -1.8 °C), ice forms naturally in polar ocean-water.  See phase diagram:   &lt;a href=&quot;http://antoine.frostburg.edu/chem/senese/101/solutions/images/saltwater-phase-diagram.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://antoine.frostburg.edu/chem/senese/101/solutions/images/saltwater-phase-diagram.gif&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Salt can freeze along with water in ice below -21 °C, but oceans tend to circulate quite efficiently, so -21 °C water is unlikely in oceans.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="725" LastEditDate="2017-05-16T07:35:44.083" LastActivityDate="2017-05-16T07:35:44.083" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8322" PostTypeId="2" ParentId="8311" CreationDate="2016-07-02T07:20:58.463" Score="6" Body="&lt;p&gt;Lava doesn't destroy water it evaporates it into steam.  This steam rises high into the atmosphere, cools and condenses into rain which it falls back onto the Earth's surface where it gets hot again, evaporates and rises.   This isn't too different than how rain is made today, except that the evaporation process is slower and mostly driven by sunlight, wind, running rivers and by plant transpiration, not as much by a scorching hot surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rain is a very efficient form of heat transfer.  Water evaporating very efficiently cools the surface.   I read or heard somewhere, don't remember where, so take with a grain of salt, but I heard that the Earth rained constantly for millions of years when the planet was young and the surface was hot.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To thermally split water into Hydrogen and Oxygen, the temperature needs to be about 2,000 degrees C.  Lava isn't that hot, though it's possible that the very young earth might have been hot enough to actually destroy some water and turn it into it's elements, Oxygen and Hydrogen, some of which would have recombined, and some of the hydrogen could have been lost as Earth's gravity is too low to retain all of it's hydrogen, but for the most part, Lava doesn't destroy water it simply evaporates it.  It's also possible that some other chemical interactions would absorb and change the chemical property of some of the water, but for the most part, Lava just turns water it into steam, which is still water, just in a different state, like how Ice is still water, just not liquid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Update:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the comments below, that's on the Earth Science/Astronomy border, but there are a fair bit of unknowns on how much atmosphere and water the Earth has lost to the Solar Wind.   One estimate says the Earth is losing about 90,000 tons of hydrogen every year.   &lt;a href=&quot;http://scitechdaily.com/earth-loses-50000-tonnes-of-mass-every-year/&quot; rel=&quot;nofollow&quot;&gt;Source&lt;/a&gt;.  Since that hydrogen effectively comes from split water molecules by UV rays high in the atmosphere and by mass, Water is about 8 parts Oxygen to 1 part hydrogen, then 810,000 tons of water is converted to 720,000 tons of Oxygen every year.    If we multiply that by 4 billion, just cause, you know, why not run the numbers, assuming consistency, over that time, the Earth has lost 3,240 trillion tons of water and added 2,880 trillion tons of Oxygen.  Consistency is a big if, but these numbers seem reasonable enough to work with.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The oceans contain about 1.4 million trillion tons of water so the estimated 3,240 trillion tons of water lost is irrelevant, less than 1/400th of the Ocean water at the current rate of loss.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oxygen is different.   2,880 trillion tons of Oxygen is more Oxygen than is currently in the Earth's atmosphere, but much of the Earth Oxygen formed in the upper atmosphere combined with other elements like Iron in the oceans or Methane gas, or helped form the planet's granite, so even though the solar radiation should have produced lots of Oxygen from water over time and Hydrogen that was lost, the amount of water is negligible and the Oxygen has been useful in many ways.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I digress as those are current estimates not historical ones.   The solar wind, while it does blow hydrogen off the Earth and in effect removing water from the Earth, the effect is slow enough that it's a minimal change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the Earth's magnetic field wasn't always there and it isn't as old as the early and late heavy bombardment periods.  Our magnetic field is thought to be about 3.5 billion years old.  &lt;a href=&quot;http://www.wired.com/2010/03/earths-magnetic-field-is-35-billion-years-old/&quot; rel=&quot;nofollow&quot;&gt;Source&lt;/a&gt;.  So it's entirely possible that the Young Earth lost a significant amount of water prior to the magnetic field.   Venus has no magnetic field to speak of but it's retained it's atmosphere's heavy elements but very little of it's water.   Mars is much smaller, so it's less good at retaining it's atmosphere than Venus.   Nobody knows how much atmosphere and water the young Earth lost to space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's entirely possible Earth lost a pretty good share of it's water to the Sun's UV rays prior to it's magnetic field, and in part due to it's high temperature, but I don't think anyone had a good guess on the precise numbers.  To return to the question above, Magma on the surface isn't a big factor unless it's hot enough to split water into individual molecules.   It's the temperature of the upper atmosphere, the atmospheric escape velocity, the solar wind and magnetic field are the larger factors.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2016-07-05T11:43:54.673" LastActivityDate="2016-07-05T11:43:54.673" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8323" PostTypeId="2" ParentId="8315" CreationDate="2016-07-02T17:10:45.013" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;So I'm not asking about snow what is pressed into ice on the poles.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Snowfall is obviously important for the ice that overlies Greenland and Antarctica; snowfall is the only source for ice on land. On the other hand, most of the ice in the Arctic Ocean and in the seas that surround Antarctica result from the freezing of seawater as opposed to snowfall. Snowfall does of course add a bit, but it is important to keep in mind that much of the Arctic and Antarctic are essentially deserts. There's essentially no water content in the atmosphere when the temperature is forty degrees below zero, even at 100% humidity. On the other hand, that extremely cold air fuels freezing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding water vapor content, the following figure from &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Relative_Humidity.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia Commons&lt;/a&gt; may help:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/4/41/Relative_Humidity.png&quot; alt=&quot;Water vapor pressure at 50% and 100% relative humidity as a function of temperature&quot;&gt;&lt;br&gt;&#xA;&lt;sup&gt;(Copyright Greg Benson 2007, image used per CC-BY-SA license)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This curve (&lt;a href=&quot;https://physics.stackexchange.com/questions/237714/what-determines-the-shape-of-the-100-relative-humidity-curve&quot;&gt;along with the physics behind it&lt;/a&gt;) is one of the key reasons polar regions qualify as &quot;deserts&quot;. Polar regions do not and cannot receive much precipitation.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="-1" LastEditDate="2017-04-13T12:40:15.470" LastActivityDate="2016-07-02T20:19:30.720" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8324" PostTypeId="1" CreationDate="2016-07-03T11:36:40.427" Score="2" ViewCount="1368" Body="&lt;p&gt;I am trying to understand how a dense basaltic lava is able to rise and punch through the continental crust, such as in mantle plumes or the Great East African Rift. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My understanding of plate tectonics is that continental crust is made from less dense silicates, where as oceanic crust is made from denser silicates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The origin of continental crust is from the differentiation of Earth, where silicates rose to form the mantle and even lighter silicates rose, then cooled, to form the crust of early cratons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the mantle that forms oceanic crust is composed of dense silicates, how is it able to rise up and punch through the continental crust, pushing it apart to form ocean basins, as in areas of rifting or mantle plumes?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My intuition tells me a dense material should not be able to rise from depth and displace a lighter one.&lt;/p&gt;&#xA;" OwnerUserId="5923" LastActivityDate="2016-07-06T11:49:56.180" Title="How is dense magma able to rise and punch through continental crust?" Tags="|geology|plate-tectonics|mantle|continental-rifting|crust|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8325" PostTypeId="2" ParentId="8324" CreationDate="2016-07-03T12:39:47.000" Score="7" Body="&lt;p&gt;Your intuition is quite correct: &lt;em&gt;Other factors being equall&lt;/em&gt;, a dense magma will not rise through lighter rocks. The exception is if it is under pressure, in which case a fluid magma will escape through 'pressure release' pathways, either laterally or vertically (or in complex geologic structures, in a variety of irregular pathways). Magmas may begin to crystallize at depth. As they do so, the volatile components, such as water, carbon dioxide, halogen acids, and sulphur dioxide, become relatively enriched in the residual magma, where they can build up enormous gas pressures. The most spectacular results are in Plinian-type volcanoes, and in many less dramatic eruptions. Consider, for example, pumaceous lava, which is essentially gas bubbles frozen-in during the process of escape. At depth there are no such bubbles. but the gasses are still there, and still exerting a huge pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Otherwise, a magma may simply rise because of thermal expansion reducing the density to less than that of the host rock. Most likely the magma will rise as a combination of both mechanisms. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, you mention the Great East Africa Rift, which is notable for some extraordinary carbonatite lavas and related carbonatite-silicate hybrids, which are less dense than almost all of the other African crustal rocks. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-07-03T12:39:47.000" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8326" PostTypeId="1" CreationDate="2016-07-03T14:48:12.540" Score="2" ViewCount="1690" Body="&lt;p&gt;Structural geologists use Mohr diagram to evaluate stress on rock's surface, but I find it difficult to understand how this diagram works (Though I am good at math). Where can I find a good explanation of Mohr diagram?    &lt;/p&gt;&#xA;" OwnerUserId="6246" LastActivityDate="2016-10-10T18:23:07.147" Title="How to understand Mohr diagram?" Tags="|geology|structural-geology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8327" PostTypeId="1" AcceptedAnswerId="18904" CreationDate="2016-07-03T15:10:49.273" Score="1" ViewCount="1774" Body="&lt;p&gt;Some features of Earth (and beyond) have been bugging me for quite some time.  When molten rock is beneath the surface, it's called &quot;magma&quot;.  Above the surface, it is called &quot;lava&quot;.  When a bolide is in orbit of any planet, it's called a &quot;meteoroid&quot;.  When it makes contact with the atmosphere, it becomes a &quot;meteor&quot;.  When it hits the surface, it becomes a &quot;meteorite&quot;.  But changing one's name based on a change in location is, at best, superficial and has no relation to chemistry and composition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any REAL differences between magma and lava?  Are there any REAL differences between a meteoroid, a meteor and a meteorite?  If not, then why do we call them by different names?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastActivityDate="2020-01-07T17:12:32.993" Title="Lava and Magma, Meteor and Meteorite--What's the Difference?" Tags="|volcanology|meteorite|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8328" PostTypeId="1" CreationDate="2016-07-03T15:28:46.817" Score="0" ViewCount="339" Body="&lt;p&gt;Let's assume that the climate change won't be prevented. I'm looking for a guide to show how the climate change will affect different countries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Specifically, I'm interested in comparing following countries:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Switzerland&lt;/li&gt;&#xA;&lt;li&gt;Panama&lt;/li&gt;&#xA;&lt;li&gt;Chile&lt;/li&gt;&#xA;&lt;li&gt;Uruguay&lt;/li&gt;&#xA;&lt;li&gt;Malaysia&lt;/li&gt;&#xA;&lt;li&gt;Ukraine&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I'm looking for a guide which would combine as many known factors as possible, like sea level rise, ocean acidification, impact of climate change on agriculture (Ukraine) or growing forests (Panama), fisheries (Chile) etc etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is some basic information &lt;a href=&quot;http://index.gain.org/ranking&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;, but I feel that this index is too basic, and doesn't give any idea about concrete dangers faced by each country in the list&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone recommend to me a source which can be used to imagine the future as vividly as possible for each country in question? I am interested in the estimates for the next 300 years&lt;/p&gt;&#xA;" OwnerUserId="5971" LastEditorUserId="11908" LastEditDate="2019-03-17T19:44:27.507" LastActivityDate="2019-03-17T19:44:27.507" Title="A guide to how climate change will affect different countries" Tags="|climate-change|climate|sea-level|climate-models|" AnswerCount="2" CommentCount="2" ClosedDate="2016-07-06T11:03:20.370" ContentLicense="CC BY-SA 3.0" />
  <row Id="8329" PostTypeId="2" ParentId="7056" CreationDate="2016-07-03T18:17:34.850" Score="0" Body="&lt;p&gt;We can see the Moon's shape, right? We can see the Sun's shape too, right? And lots of other planets through telescopes? Does any of those looks flat to anyone? I guess not! Then, thinking further, I guess Earth cannot be flat...&lt;/p&gt;&#xA;" OwnerUserId="6247" LastActivityDate="2016-07-03T18:17:34.850" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="8330" PostTypeId="1" CreationDate="2016-07-03T19:57:20.333" Score="5" ViewCount="123" Body="&lt;p&gt;Is there any up-to date and reliable map or overview or database of the oceans pollution with respect to fish pollution (PCB, mercury, dioxines, tin compounds etc.)?&lt;/p&gt;&#xA;" OwnerUserId="6248" LastActivityDate="2016-07-03T19:57:20.333" Title="Overview/map of pollution level of worldwide fishing zones" Tags="|ocean|pollution|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8331" PostTypeId="2" ParentId="8328" CreationDate="2016-07-03T22:25:11.383" Score="4" Body="&lt;p&gt;There's a fair bit of unknowns for what you're asking, 300 years and specifics.   For one, climate change modeling is based off CO2 levels and CO2 levels long term are difficult to predict.   That's why they run hundreds of models, each with different circumstances.  Nobody can make an accurate assessment of mankind's CO2 output will be 50 or 100 years so the further out you go the greater the unknowns.  Targets are being set for 2050, but whether they will be reached is a big unknown and I've never seen anything that goes for 300 years.  Most of the models run till 2100.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Some Unknowns&lt;/strong&gt;: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Will CO2 PPM peak at 500 or 600 or higher?   Will it fall below 400&#xA;in 100 years?&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Will the oceans continue to absorb CO2 or will they warm to the point&#xA;where they stop.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Will the North Atlantic current stop or weaken?   That would have an &#xA;enormous effect on European climate.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Will large chunks of ice break off or will the ice sheets remain&lt;br&gt;&#xA;mostly intact?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;These are impossible things to predict with any accuracy and they significantly effect the outcomes you've asked for.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Smaller effects, such as whether the Sun will enter an extended solar minimum or whether we have a big volcanic eruption like the one in 1815 (which would slow things down for 5-10 years, but wouldn't have a significant long term effect).   Other questions are whether parts of the Earth can be greened, artificially, which might not measurably slow down the warming but it could ease the effects of drought in some areas.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bottom line is that &quot;basic&quot; predictions might be just as good as detailed because of all the unknowns.   A few aspects are pretty straight forward, like knowing the effect of 1 foot of sea level rise, but predicting how fast the oceans will rise 1 foot is very difficult.   The effects of ocean acidity and some weather driven species migration is somewhat predictable too.   Predicting where droughts are more likely to happen can be done as well, but as I said above, might be preventable with strong irrigation efforts.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rough predictions aren't hard to find, but for the 21st century only.  Anything further out than that is probably lots of guesswork and not carefully modeled.    Basic and this century is probably as good as this field of study gets.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Articles &lt;a href=&quot;http://www.huffingtonpost.com/2013/10/30/climate-change-vulnerability-index-countries-impacts-costs_n_4174938.html&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;http://www.cgdev.org/page/mapping-impacts-climate-change&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;.  I imagine those are both based on the &lt;a href=&quot;http://www.ipcc.ch/report/ar5/&quot; rel=&quot;nofollow&quot;&gt;5th assessment report&lt;/a&gt;.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;footnote:  If you read assessment reports online, keep in mind the labeling system - 5th; AR5,  4th; AR4, 3rd; TAR, 2nd; SAR, first; FAR.  Given how fast this field tends to update, I'd mostly just read IPCC reports labeled AR5, perhaps AR4.   Anything before then is quite dated by now.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2016-07-04T02:11:15.950" LastActivityDate="2016-07-04T02:11:15.950" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8332" PostTypeId="1" AcceptedAnswerId="8336" CreationDate="2016-07-04T06:27:45.663" Score="3" ViewCount="2323" Body="&lt;p&gt;We know that the ocean depth is varies from ocean to ocean. Mariana trench is about 11 km deep. If we consider as a whole, what is the average depth of the ocean?&lt;/p&gt;&#xA;" OwnerUserId="6239" LastEditorUserId="18081" LastEditDate="2022-08-04T08:37:25.030" LastActivityDate="2022-08-04T08:37:25.030" Title="What is the average depth of the ocean?" Tags="|oceanography|bathymetry|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8333" PostTypeId="1" AcceptedAnswerId="8338" CreationDate="2016-07-04T06:44:26.557" Score="7" ViewCount="1292" Body="&lt;p&gt;I've always thought the earth's layers were as follows:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Crust, a few dozen KM think in most places&lt;/li&gt;&#xA;&lt;li&gt;Mantle, completely composed of liquid rock and molten metals, a few thousand KM thick&lt;/li&gt;&#xA;&lt;li&gt;Outer Core, molten iron&lt;/li&gt;&#xA;&lt;li&gt;Inner core, solid iron&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The mantle being composed of a liquid made a lot of sense. The idea of plate tectonics floating on top of magma and bumping against each other made sense. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, &lt;a href=&quot;https://physics.stackexchange.com/questions/239003/does-the-thickness-of-earths-crust-accurately-correspond-with-the-current-propo&quot;&gt;I've been told by Michael&lt;/a&gt; that the mantle is completely solid, which seems to not work as well with the ideas of&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Floating/moving plate tectonics&lt;/li&gt;&#xA;&lt;li&gt;Convection currents&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;If the earth's mantle is solid, why don't we say the plate tectonics are &quot;resting on&quot; the mantle instead of &quot;floating on&quot;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can we have convection currents through something that doesn't flow? Even if the solid rock in the mantle can why doesn't the heat just distribute itself evenly through conduction, and negate any convection tendencies?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I realize that entire books can be written on this topic, so a generalized answer is fine.&lt;/p&gt;&#xA;" OwnerUserId="6072" LastEditorUserId="-1" LastEditDate="2017-04-13T12:40:15.470" LastActivityDate="2016-07-06T11:38:19.433" Title="How can we have &quot;floating&quot; and convection currents in a non-liquid mantle?" Tags="|plate-tectonics|mantle|convection|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8334" PostTypeId="2" ParentId="8328" CreationDate="2016-07-04T06:51:05.290" Score="2" Body="&lt;p&gt;The world is awash with vague and worthless generalizations and politically correct 'risk-vulnerability matrices'. But if you want worthwhile estimates of the future then there is no short cut. There is no alternative to actually calculating the specific results yourself. Firstly, one doesn't calculate the climate change impact by country. One calculates by grid block, as per the defined cells in atmospheric-ocean coupled global climatic model. You will need to assess the output of at least a dozen, preferably about 16, different models for maximum, minimum and mean monthly temperatures. Repeat this for your chosen carbon emissions scenarios. We are currently on track for the disastrous RCP 8.5 scenario, but if the world comes to its' collective sense then you could probably use RCPs 4.5 and 6.0. Forget about RCP 2.8, which is now just an exercise in wishful thinking. There are several climate-change sources, such as the World Bank climate change portal, on the internet from where the model outputs are published - albeit on models which are already out of date (they are being refined all the time). Having calculated the temperatures for each scenario, carry out your preferred statistical assessment of the wide range of model outputs for various time-slices for as far into the future as you feel confident about the model's capacity. This gives you the likely temperature changes for the given emissions scenario, and time horizon. Repeat all of this for as many grid cells as you deem representative of your country of interest.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I recommend that you do &lt;strong&gt;&lt;em&gt;not&lt;/em&gt;&lt;/strong&gt; use the published model outputs for rainfall, or indeed for any water-related parameter (humidity, soil moisture deficits, evapotranspiration, open-water evaporation, etc). GCMs were never designed for this, and are inaccurate to wildly misleading. For these parameters, use evidence-based trends from existing instrumental time-series of rainfall (corrected for systematic error and discontinuities), using rigorous statistical testing of confidence limits. Use the corrected rainfall, humidity, temperature, wind, and hours of bright sunshine to plug into the Penmann-Monteith equation for evapotranspiration (The solar radiation can be calculated by altitude and coordinates on the same internet site as the ET0 calculators). Use the ET0 data and FAO crop factors to estimate changes in crop water requirements for the time frame of your study. Use all of the above, and specialist subject area searches to assess the likelihood of such factors as land degradation, desertification, crop failure frequency, drought frequency, disease vector mobility, stress on stock, stress on humans, and other inland issues. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sea level rise is something else which takes in coastal aquifer contamination, coastal flooding, ecological changes, fisheries breeding, coral bleaching and reef degradation, and synergies of temperature, dissolved oxygen, pollution and other human impacts, frequency of oceanic oscillations, and changes in coastal dynamics. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can add sophistication to your climatic analysis by modifying your instrumental trend projections to a more reasonable non-linear form, such as an error-function transition to an assumed climatic plateau in the distant (post 2100) future. For the sea level rise there is no sign of any quasi- equilibrium being regained, at least before 2400 (if then), so a second-order sea level rise projection is about the best we can do at present, with the caveat that uncalibrated feedback processes are likely. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short, what you are asking is at least a man-year of intensive work by someone who knows what he/she is doing - make that two man-years if you include the rising sea level. So it isn't surprising that you can't find the detailed studies that you seek. Some regions of some countries have gone through this exercise, generally with a team of specialists. In all such cases that I know of, the results are in official ministry reports, and are not easily found through public access. Further, even at the end of this lengthy process the results are still subject to many uncertainties and caveats, including those mentioned earlier by 'userLTK'.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-07-04T06:51:05.290" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8335" PostTypeId="2" ParentId="8333" CreationDate="2016-07-04T07:05:03.430" Score="7" Body="&lt;p&gt;Humans have difficulty visualizing how rocks flow because the required conditions are outside our everyday experience. We are familiar with surface temperatures and pressures, and geologically short time-frames, where the distinction between solid and liquid is obvious. Under very high temperatures and pressures, and especially over longer time periods, solids can assume plasticity, almost like a fluid, albeit a fluid with ultra-high viscosity. You can see the outcome of these changed rock properties when rocks, which have undergone deformation at depth, are brought back to the surface. Drive or trek through any mountainous area where the mountain roots have been exposed by deep erosion, and you will see dramatic folding - examples of rock plasticity. The mantle is much deeper, hotter and under immense confining pressure, so yes, the mantle &lt;em&gt;can&lt;/em&gt; have convection cells without being a liquid.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-07-04T07:05:03.430" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8336" PostTypeId="2" ParentId="8332" CreationDate="2016-07-04T07:10:37.303" Score="4" Body="&lt;p&gt;About four kilometers, see, for example:&#xA;&lt;a href=&quot;http://www.mbgnet.net/salt/oceans/data.htm&quot; rel=&quot;nofollow&quot;&gt;http://www.mbgnet.net/salt/oceans/data.htm&lt;/a&gt; &#xA;But bear in mind that much of the oceans, especially in the southern hemisphere, have scarcely been mapped at all, so it is currently impossible to give an accurate estimate. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-07-04T07:10:37.303" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8337" PostTypeId="2" ParentId="8327" CreationDate="2016-07-04T09:34:53.057" Score="2" Body="&lt;p&gt;There is a real difference between lava and magma. Magma contains lots of water and various gases. When it reaches earth's surface, it looses most of its volatiles and becomes lava.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, magma is volatile rich lava.    &lt;/p&gt;&#xA;" OwnerUserId="6246" LastEditorUserId="5594" LastEditDate="2016-07-04T10:35:56.217" LastActivityDate="2016-07-04T10:35:56.217" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8338" PostTypeId="2" ParentId="8333" CreationDate="2016-07-04T10:01:40.393" Score="9" Body="&lt;p&gt;&lt;strong&gt;Is the mantle solid?&lt;/strong&gt;&lt;br&gt;&#xA;It's all a matter of timescales. The mantle is undoubtedly solid (except locally in the uppermost regions where melting can occur) but on a long enough timescale it can display plastic behaviour under high temperatures and pressures, with a viscosity on the order of $\text{~}\mathrm{10^{21}~Pa~s}$ (based on estimates from isostatic rebound after melting of ice sheets). Think of plasticine - it is obviously solid but it deforms easily under stress. This is how the mantle behaves on long timescales at high temperatures and pressures. On short timescales the mantle is a brittle solid and this is what allows it to transmit seismic S-waves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Why does the crust 'float' on top of the mantle?&lt;/strong&gt;&lt;br&gt;&#xA;The answer to this is quite simple - the crust is less dense than the mantle and so on the long timescales, where the mantle is ductile, the crust does not sink into the mantle (except at subduction zones but that's another story). Granitic continental crust has an average density of around $\mathrm{2.6~g~cm^{-3}}$, basaltic oceanic crust is around $\mathrm{3~g~cm^{-3}}$, and the upper mantle is around $\mathrm{3.5~g~cm^{-3}}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How does convection work in the mantle?&lt;/strong&gt; &lt;br&gt;&#xA;The details of mantle convection are a subject of active research but all geologists agree that the mantle does convect vigorously and that this is the major form of heat transport from the core to the crust. If you calculate the Rayleigh number for the mantle you come out with $R_a~\text{~}~10^6$ which indicates that convection should be vigorous. On the other hand, the thermal diffusivity of the mantle is very low ($\text{~} \mathrm{10^{-6}~m^2~s^{-1}}$) and so conduction is not the dominant form of heat transport.&lt;/p&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2016-07-04T10:01:40.393" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8340" PostTypeId="2" ParentId="8317" CreationDate="2016-07-04T20:48:04.783" Score="2" Body="&lt;p&gt;Looking at the source you provided in the comment, there is some other information you may be able to accumulate to help your study.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Control or Baseline.  You need an the same actual set of data from a facility in the area that &lt;em&gt;is&lt;/em&gt; meeting the above-mentioned standards.  This needs to be as close to your target facility in size, structure and regional conditions as you can find so you can demonstrate that under the same Temperature and Humidity proper conditions can be maintained.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;More Data.  You haven't mentioned Time in your question. Most building temperature studies show conditions throughout the day. The duration that the animals are exposed to extreme conditions may be relevant.  There are data-logging thermometer type devices available , or you may need to perform your tests once an hour during the day to collect enough relevant data to make your case.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;More Data. You talk of taking measurements on an extreme day. Gather data on a variety of days, and you may find the care standards are exceeded more (or less) often then you expect.  This way you may find the lower limit of conditions which cause problems. Which brings us to...&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;More Data.  Once you have a measured example of the problem temperature and humidity reading, for a given day, you can collect data from local weather sources and you can present a graphic showing the number of days, or perhaps hours per year the animals are exposed to these conditions.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;You mention Heat Index. According to &lt;a href=&quot;http://www.srh.noaa.gov/ama/?n=heatindex&quot; rel=&quot;nofollow&quot;&gt;NOAA,  Heat Index&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;is what the temperature feels like &lt;strong&gt;&lt;em&gt;to the human body&lt;/em&gt;&lt;/strong&gt; when relative&#xA;  humidity is combined with the air temperature... &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You might have to prove the relevance of this data to animals which do not react the same way to humidity. If you can find an external source supporting your use of that index, then by all means continue to use it. You may even be able to find a study showing that the &lt;a href=&quot;http://www.humanesociety.org/animals/resources/tips/pets_safe_heat_wave.html?referrer=https://www.google.com/&quot; rel=&quot;nofollow&quot;&gt;animals feel the effects of humidity&lt;/a&gt; more then humans do. Look for, more data. The link above mentions a possible place to begin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Personally I believe the main argument you will face would be the amount of time the proper conditions are exceeded. Like the people who leave the dog in the car, 'but it was just for a minute...'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Good luck, no matter what results you find.&lt;/p&gt;&#xA;" OwnerUserId="6057" LastActivityDate="2016-07-04T20:48:04.783" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8341" PostTypeId="1" CreationDate="2016-07-05T01:10:27.920" Score="0" ViewCount="70" Body="&lt;p&gt;I am looking for a kind of crystal that can be artificially made at relatively low temperatures (below 1500 degree Celsius) and relatively quickly (not geological time). The product is ideally monocrystalline, not reactive to oxygen or moisture and not metallic. Ice is excepted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If such a material exist, I would like to know its name, composition and any other noteworthy properties. If there is anything wrong with the premises of the question, please point it out.&lt;/p&gt;&#xA;" OwnerUserId="6253" LastActivityDate="2016-07-06T01:09:47.573" Title="Is there any covalent crystals that can be easily synthesized?" Tags="|rocks|mineralogy|crystals|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8342" PostTypeId="1" CreationDate="2016-07-05T09:24:04.583" Score="5" ViewCount="337" Body="&lt;p&gt;First all, my question was different from the question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7350/converting-grid-resolution-from-degrees-to-kilometers&quot;&gt;Converting grid resolution from degrees to kilometers&lt;/a&gt;.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In chemical transport modeling, the pollutant source inventory was an essential input which contain residential, industrial, agriculturial, vehicle emission in the area of interest.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The source inventory can be built independently or downloaded from the websites of several institutions which support some global/regional source information dataset.       &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://cgrer.uiowa.edu/projects/emmison-data&quot; rel=&quot;nofollow noreferrer&quot;&gt;INTEX-B&lt;/a&gt;   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It contain different emission species like SO2, NOx, CO, NMVOC in the resolution of 0.5 degree x 0.5 degree   &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://www-air.larc.nasa.gov/missions/tracep/tracep.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tracer-P&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.nies.go.jp/REAS/&quot; rel=&quot;nofollow noreferrer&quot;&gt;REAS&lt;/a&gt; -&gt; Regional Emission inventory in ASia&lt;br&gt;&#xA;Spatial resolution: 0.25 degree by 0.25 degree&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://edgar.jrc.ec.europa.eu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;EDGAR&lt;/a&gt; The Emissions Database for Global Atmospheric Research&lt;br&gt;&#xA;spatial resolution:  0.1deg x0.1deg and 0.5deg x0.5deg &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;These source inventories are all gridded in  geographic coordinate. But for regional/small scale research, the simulation grid was set in the unit of kilometers(For example, 36 km for regional simulation, 4 km for urban simulation).   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then, I want to re-arrange the source inventory into km x km cell. Due to different distance corresponding to the same degrees gap along the latitude, the degree-cell can't be transform into kilometer-cell directly.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If directly, the width of each cell&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\Delta y=2\pi R_e\frac{\Delta lat}{360^\circ}$$      &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The length of each cell:      &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\Delta x=2\pi R_e\cos(lat)\frac{\Delta lon}{360^\circ}$$   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, every cell has its own size in kilometers. The uneven grid networks enhance the difficulty for simulation. I'm wondering to transform the inventory into uniform grid in kilometers(for example: 0.25 degree x 0.25 degree -&gt; 36 km x 36 km)  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How to achieve it? I'm familiar with Python language.&lt;br&gt;&#xA;Any advice would be appreciate!&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2018-03-22T11:37:05.097" Title="How to transform the inventory data from degrees to kilometers" Tags="|atmosphere|atmosphere-modelling|atmospheric-chemistry|air-pollution|wrf|" AnswerCount="0" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="8343" PostTypeId="1" AcceptedAnswerId="8347" CreationDate="2016-07-05T09:43:13.400" Score="4" ViewCount="410" Body="&lt;p&gt;We know that this natural disaster can cause a big damage. I have heard that we can identify such areas by some geographical signs, such as curved trees. Do we have any stronger detectable signs which we can observe easily?&lt;/p&gt;&#xA;" OwnerUserId="6239" LastEditorUserId="6239" LastEditDate="2016-07-05T11:04:06.207" LastActivityDate="2016-07-25T15:54:17.417" Title="How to identify a landslide area early?" Tags="|soil|land-surface|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8344" PostTypeId="1" CreationDate="2016-07-05T15:20:07.007" Score="1" ViewCount="48" Body="&lt;p&gt;(I'm not saying global warming isn't a thing!)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, any fool will tell you that cloudy days are colder days, some times significantly so. When there are multiple cloudy days the temperature will plummet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if The oceans evaporate due to heat, clouds will form. If clouds form, more sunlight gets reflected into space. When sunlight is reflected, everyone wins (or at least doesn't cook).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, what am I missing here? If it's not obvious, my understanding of climatology is limited to the news and a 5th grade understanding of the water cycle, so simple explanations would be preferable if possible.&lt;/p&gt;&#xA;" OwnerUserId="5673" LastActivityDate="2016-07-05T15:20:07.007" Title="Why is the increased albedo from cloud cover not expected to counteract global warming?" Tags="|climate-change|clouds|" AnswerCount="0" CommentCount="2" ClosedDate="2016-07-05T17:10:09.933" ContentLicense="CC BY-SA 3.0" />
  <row Id="8346" PostTypeId="1" CreationDate="2016-07-05T19:00:37.557" Score="6" ViewCount="9807" Body="&lt;p&gt;I've read that 80% of sunlight is passing through clouds. Now there a small clouds and big clouds so it should be some average. Is this true or is the amount of sunlight passing throug a cloud really much more depending on the size of clouds. Is it for instance on a totally cloudy day that only 30% is passing and on a nice summerday when a cloud comes by it is 90%. Probably it depend on how high in length the clouds are.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But perhaps even a more interesting question is, are all wavelengths passing though on the same level? So is uv-light passing even easy as infrared light? In my experience though when walking in the sun it feels that much more than 20% of those warm IR-rays are being blocked by clouds (even if they are very tiny). So is it possible that even 70% of the IR rays are blocked or perhaps relatively moren than visible light or UV-light?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="124" LastEditDate="2016-07-25T20:26:29.743" LastActivityDate="2019-11-26T15:11:43.697" Title="How much and what kind of radiation passes through a cloud?" Tags="|meteorology|atmosphere|atmospheric-radiation|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8347" PostTypeId="2" ParentId="8343" CreationDate="2016-07-05T19:17:08.927" Score="5" Body="&lt;p&gt;Curved trees are a sure sign of movement of surface. Special geomorphic shapes are also present in a slowly developing landslide. At the top of the landslide cracks can start to show, at the foot you can find &quot;bumps&quot; in the soil. Water will have difficulties to drain at the foot of the landslide. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are a few examples of literature that should be something to start with:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://ny.water.usgs.gov/pubs/jrn/ny0155/jrn02-r20500g.pdf&quot; rel=&quot;noreferrer&quot;&gt;http://ny.water.usgs.gov/pubs/jrn/ny0155/jrn02-r20500g.pdf&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.ags-hk.org/notes/09/Geomorphology_and_Landslide_Hazard_Models_Steve_Parry.pdf&quot; rel=&quot;noreferrer&quot;&gt;http://www.ags-hk.org/notes/09/Geomorphology_and_Landslide_Hazard_Models_Steve_Parry.pdf&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.adpc.net/casita/pdf/01-Geomorphic-mapping.pdf&quot; rel=&quot;noreferrer&quot;&gt;http://www.adpc.net/casita/pdf/01-Geomorphic-mapping.pdf&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6256" LastEditorUserId="534" LastEditDate="2016-07-06T04:37:02.883" LastActivityDate="2016-07-06T04:37:02.883" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8348" PostTypeId="2" ParentId="8346" CreationDate="2016-07-05T21:01:31.643" Score="7" Body="&lt;p&gt;Here is not a detailed article, but one you might find some informative thoughts in:  &lt;a href=&quot;https://web.archive.org/web/20170502011616/http://www.americanscientist.org/issues/pub/sunshine-on-a-cloudy-day&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.americanscientist.org/issues/pub/sunshine-on-a-cloudy-day&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On a basic note, any generalization starting with &quot;clouds block x or x%&quot; are far too general to compare actual percentages.  It assumes a cloud is a cloud is a cloud.   They are not.  What a cloud actually does to block or not block electro-magnetic radiation is not an absolute.  It varies by type of cloud, thickness, altitude, angle of the sun and likely many other factors.  As a generality, clouds block a part of visible, UV and IR light depending on a number of factors especially depth of the cloud.  Some of the EM waves are absorbed, some reflected and others pass through.  The UV end of the spectrum tends towards passing through while the IR end is more prone to being reflected which helps to create a greenhouse effect.  These are often presented as absolutes, but are actually generalities. &lt;/p&gt;&#xA;" OwnerUserId="6178" LastEditorUserId="18399" LastEditDate="2019-11-26T15:11:43.697" LastActivityDate="2019-11-26T15:11:43.697" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="8350" PostTypeId="2" ParentId="8341" CreationDate="2016-07-06T01:09:47.573" Score="2" Body="&lt;p&gt;Silicon carbide is covalent and can be synthesized at atmospheric pressure by the Acheson process. Temperatures may actually be somewhat higher than your range but are easily achieved by the process.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1,4 dichlorobenzene (used in moth balls) is a compound that forms crystals at low temperatures. I think the molecules in the crystal are joined only by weak bonds so I don't know if that is what you are after. &lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2016-07-06T01:09:47.573" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8351" PostTypeId="1" CreationDate="2016-07-06T02:27:04.147" Score="1" ViewCount="401" Body="&lt;p&gt;Recently, I was flying out of the midwest during a lightning storm, and I was able to see lightning both above and below the clouds. I noticed that the lightning below the clouds was orangish/yellowish and traveled in closer to a straight line without very many forks, and often appeared to strike along virtually the same path multiple times in quick succession. It looked sort of like this.&lt;br&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ZRl6a.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZRl6a.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;The lightning above the clouds however, was more of a whitish/bluish color, had a lot of forks in it, and never seemed to follow the same path, though it did strike at about the same frequency. It looked much like this.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/QyXMh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QyXMh.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing I did notice as well was that the yellowish lightning seemed mostly vertical, while the whitish lightning seemed mostly horizontal. Also, this occurred during the night, so there was no sunlight to change colors of anything.&lt;/p&gt;&#xA;" OwnerUserId="6260" LastActivityDate="2016-07-06T02:27:04.147" Title="What causes lightning to be a different color above the clouds than below the clouds?" Tags="|lightning|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8353" PostTypeId="1" CreationDate="2016-07-06T07:32:21.490" Score="8" ViewCount="693" Body="&lt;p&gt;I am looking for a publicly available, easy to download, small data set of ensemble forecasts (or reforecasts), with corresponding observations or reanalysis. We are planning to illustrate some methods for a small software package, so ideally, the data set should be available for the foreseeable future, or even better, freely distributable. Further, ideally, the data set would be given as SV or text file (anything that can be read easily without requiring additional software packages, as it would be the case with GRIB for example). Any suggestions?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By easy to download I mean: Ideally, without creating any login, for example directly possible within Python or R; small in the sense of a couple of months and data for only one location are enough; there should be some verifying observation or re-analysis associated with the forecasts&lt;/p&gt;&#xA;" OwnerUserId="5471" LastEditorUserId="20" LastEditDate="2016-07-06T21:11:56.790" LastActivityDate="2022-11-28T19:42:13.593" Title="Publicly available data set with ensemble forecasts and observations?" Tags="|meteorology|weather-forecasting|open-data|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8354" PostTypeId="2" ParentId="8291" CreationDate="2016-07-06T10:43:30.630" Score="3" Body="&lt;p&gt;As far as I know; no. Lightning can either come from large amounts of friction in the atmosphere, or from a discharge of built up energy sourced from space (primarily solar radiation) captured by Earth's magnetosphere. The same energy that causes the Auroras. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, clouds will probably be present regardless of the source of the energy. &lt;/p&gt;&#xA;" OwnerUserId="6125" LastActivityDate="2016-07-06T10:43:30.630" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8355" PostTypeId="2" ParentId="8333" CreationDate="2016-07-06T11:37:55.710" Score="4" Body="&lt;p&gt;I'd like to add to the correct answers already given.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Solids can flow and deform without being a liquid. You can bend iron bars. You can dent plastic. You can squeeze nylon bags. The cotton on your t-shirt bends as you move you hand. These are all solids. The ability of this to happen depends on temperature and pressure. Iron bars bend easier when heated. I'm sure you know that freezing (already solid) objects with liquid nitrogen makes them much more brittle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most obvious difference between solids and liquids is their ability to deform, but that does not mean that only liquids do it. Liquids do not have crystal structures, whereas (some) solids do. Take H&lt;sub&gt;2&lt;/sub&gt;O: water is liquid, but ice is solid. However, glaciers can deform and move. All in the solid state. Metamorphic rocks deform, in the solid state.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once we accept that solids can deform without being liquid, the ability to sustain convection cells and density-based stratification are not surprising. Fill in a box with gummi bears, then drop a huge block of steel on to it. Eventually the candy will flow upwards while the steel block will sink. All of this will happen in the solid state.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-07-06T11:37:55.710" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8356" PostTypeId="2" ParentId="8324" CreationDate="2016-07-06T11:49:56.180" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The origin of continental crust is from the differentiation of Earth,&#xA;  where silicates rose to form the mantle and even lighter silicates&#xA;  rose, then cooled, to form the crust of early cratons.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not quite. The lighter silica rich rocks that compose the continental crust form by partial melting of pre-existing denser basaltic rocks. When you partially melt a basalt, the liquid is richer in silica, thus it is less dense.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If the mantle that forms oceanic crust is composed of dense silicates, how is it able to rise up and punch through the continental crust, pushing it apart to form ocean basins, as in areas of rifting or mantle plumes?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That is because basaltic magma is less dense than basaltic solid rocks. Basaltic magma may very well be less dense than any silica rich rock it encounters. Furthermore, as Gordon mentioned, there is the issue of overpressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mantle plumes are mostly solid - these are areas that are hotter than their surroundings but are still solid. However, hotter material expands and becomes less dense. This allows the lighter rocks, which are chemically similar to their surroundings, to flow upwards. Melting occurs only at a later stage, either because you depressurise the mantle rocks at shallower depths or because the mantle plume heats up other crustal rocks which melt more easily.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-07-06T11:49:56.180" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8357" PostTypeId="2" ParentId="8290" CreationDate="2016-07-06T12:00:17.910" Score="5" Body="&lt;p&gt;This is a very interesting topic that in the past several years has reached the spotlight because of the work of Robert Hazen on the concept of &quot;mineral evolution&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Minerals are basically just inorganic compounds: you take several elements, arrange them in certain ways and you get minerals. Thus, the minerals will be mostly determined by what's available to them in term of chemical elements. The solar nebula in Earth's area was composed of very few major elements: Fe, Si, Mg, Al, O, C, etc. There are not many ways you can arrange this limited number of elements, and the mineral diversity was rather small. You cite the number 60. Could be more, could be less, but it sounds about right.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With time, certain processes on Earth (magmatic, metamorphic, metasomatic, hydrothermal, you name it) preferentially move certain elements relative to others. This causes redistribution of elements in space, enriching and depleting certain elements in various areas. Elements that were previously present only in trace amounts and did not form minerals of their own may be concentrated so that they do.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a time dependent process, hence the name &quot;mineral evolution&quot;. This is a nice figure that sums things up:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/598Ca.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/598Ca.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can read more about it in Hazen's website (from which I took the above figure): &lt;a href=&quot;http://hazen.carnegiescience.edu/research/mineral-evolution&quot; rel=&quot;noreferrer&quot;&gt;http://hazen.carnegiescience.edu/research/mineral-evolution&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Be careful though when searching for &quot;mineral evolution&quot; online - you usually get more results of pseudoscientific and creationist websites rather than actual science.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-07-06T12:00:17.910" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8358" PostTypeId="2" ParentId="8307" CreationDate="2016-07-06T13:18:50.997" Score="2" Body="&lt;p&gt;I had asked the same question on ResearchGate and got some good feedback. So anyone who is interested in this kind of methodology can follow the link below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.researchgate.net/post/What_is_the_best_way_to_mount_white_mica_separates&quot; rel=&quot;nofollow&quot;&gt;https://www.researchgate.net/post/What_is_the_best_way_to_mount_white_mica_separates&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6083" LastActivityDate="2016-07-06T13:18:50.997" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8359" PostTypeId="1" CreationDate="2016-07-06T14:01:24.960" Score="1" ViewCount="37" Body="&lt;p&gt;I understand that tree roots help mitigate pollution in a variety of ways, and I imagine to greatly varying extents. I get the general idea (I'll describe my thoughts below) but would like clarification through a diagram or scientific study, neither of which I can find.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've read studies on riparian forest effects on water quality, but am not aware of (and didn't easily find) studies that zoom in on how tree roots specifically reduce pollution. My current understanding is that tree roots mitigate pollution in the following ways:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;storing pollutants, by catching it (e.g. holding sediment in place) or through sorption (by plant or its associated microbial community), and &lt;/li&gt;&#xA;&lt;li&gt;fostering microbial life in and around plant matter which will degrade &amp;amp; transform pollutants into less harmful forms.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;To reiterate: I'm looking for scientific studies and/or diagrams clarifying &lt;strong&gt;how do tree roots mitigate pollution?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="4789" LastActivityDate="2016-07-06T14:01:24.960" Title="How do tree roots mitigate pollution in general? Diagram preferred" Tags="|pollution|biogeochemistry|" AnswerCount="0" CommentCount="3" ClosedDate="2016-07-08T08:58:39.997" ContentLicense="CC BY-SA 3.0" />
  <row Id="8364" PostTypeId="1" CreationDate="2016-07-07T17:18:15.283" Score="3" ViewCount="984" Body="&lt;p&gt;I'm a science fiction author looking to describe what conditions might be like at the bottom of a cylindrical shaft ~ 30 meters across and ~ 35 km deep.  It's located somewhere on the edge of Yellowstone national park (if that matters). The top is open to ambient, albeit controlled, conditions in a great big lab room. If you drop a coin down this well, there's nothing man-made in the way of it getting to the bottom.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The shaft itself uses advanced unobtanium wall liners, so the engineering challenge of keeping it from collapsing or otherwise self-destructing has been taken care of. I'm not sure how insulating the unobtanium is from the surrounding rock right now, could be &quot;none&quot; to &quot;completely,&quot; depending on how interesting that makes what's happening at the bottom.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm pretty sure the atmosphere at the bottom will be amazingly hot and dense, probably quite a bit denser than several hundred feet of water, but I'm hoping someone more knowledgeable can help out with the details.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Contributors will definitely get a mention in the acknowledgements. Big contributions will likely result in a signed copy of the final book. This will be the third book in the Gemini Gambit series, which will likely hit the shelves in late 2017/early 2018.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE&lt;/strong&gt; The hole is used as part of a super-massive geothermal power plant, so hot is good. Dense is good. I'm thinking the convection potential would perhaps make mounting ducted fan windmills somewhere also good for generating power. &lt;/p&gt;&#xA;" OwnerUserId="6271" LastEditorUserId="6271" LastEditDate="2016-07-08T23:21:40.613" LastActivityDate="2023-07-10T19:50:00.963" Title="Conditions at the bottom of a VERY deep hole" Tags="|meteorology|geophysics|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8365" PostTypeId="2" ParentId="8364" CreationDate="2016-07-07T18:35:48.907" Score="0" Body="&lt;p&gt;Atmospherically speaking, it would be incredibly hot. Considering a dry adiabatic atmosphere, it would be nearly 343 degrees Celsius (617.4 degrees Fahrenheit) hotter at the bottom than at the top. If we were to assume that it was a lapse rate of 6.5 degrees celsius per km, than the temperature would be more like 227.5 degrees celsius (409.5 degrees faherenheit) hotter. Plus, you need to start thinking about geothermal heating at that depth too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other thing to keep in mind is that the pressure of the air would be very high too. Atmospheric pressure decreases exponentially with increasing height, so it would increase exponentially with decreasing height.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming STP for outside the hole with a dry adiabatic lapse rate, the pressure at the bottom would be around 1.92*10^20 hPa. The density of the air at the bottom would also be very high.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2016-07-07T23:24:40.153" LastActivityDate="2016-07-07T23:24:40.153" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8366" PostTypeId="2" ParentId="8353" CreationDate="2016-07-07T20:52:36.533" Score="0" Body="&lt;p&gt;Synthesise your own dataset.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Get some real data, and take some averages and add some noise (or some other simple munging), such that it's not possible to get back to the original raw data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then you've got a realistic data set that you have all the rights on, that's exactly the size that you want, in exactly the format you want, and you can distribute it however you see fit.&lt;/p&gt;&#xA;" OwnerUserId="100" LastActivityDate="2016-07-07T20:52:36.533" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8367" PostTypeId="1" CreationDate="2016-07-07T21:01:52.403" Score="-5" ViewCount="749" Body="&lt;p&gt;We are told that photosynthesis, developed a couple of billion years ago has produced all the atmospheric oxygen. I wonder, why did the process stop? Why do modern plants prefer to recover the entropy whereas ancient ones... &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Actually, the ancient ones separated the carbon-hydrogen fuel from the oxygen. The modern trees consist of this fuel which re-joins with the oxygen afterlife. But why didn't this happen to the ancient plants? Where did the ancient carbohydrates go? If it is the oil and gas we can burn it. Why do you say that we do not have enough fossils to burn all the oxygen? Where are the ancient plant bodies deposited so securely that we say for sure that they cannot come back into the contact with the oxygen?&lt;/p&gt;&#xA;" OwnerUserId="6272" LastEditorUserId="6272" LastEditDate="2016-07-24T21:54:55.563" LastActivityDate="2016-07-24T21:54:55.563" Title="Why cannot people burn all the atmospheric oxygen?" Tags="|atmosphere|carbon-cycle|fossils|oxygen|great-oxidation-event|" AnswerCount="2" CommentCount="6" ClosedDate="2016-07-08T12:55:34.900" ContentLicense="CC BY-SA 3.0" />
  <row Id="8368" PostTypeId="2" ParentId="8364" CreationDate="2016-07-07T23:34:51.603" Score="2" Body="&lt;p&gt;If it is enclosed and undisturbed there would be a risk of the heavier gasses collecting at the base of the hole, with carbon dioxide, argon, neon and xenon displacing the nitrogen and oxygen. Hence the danger of asphyxiation for any organism at that depth. Mixing, to keep the air homogeneous would also have the effect of heat transfer to further up the hole, so you will need artificial mixing and cooling. There are likely to be traces of helium and hydrogen at such depth, but not enough for the upward flow of such light gasses to have any significant mixing effect. However, hydrogen will be a potentially explosive problem at the enclosed surface environment. At these temperatures water rock reaction at the exposed base of the hole would be rapid. It is not clear whether your hole would have punched through to the mantle. I'm assuming it would, in which case there will be water vapour - hartzburgite reaction to yield more hydrogen. Serpentinization of the rock will proceed, involving about a 17% rock expansion. The rate of such a reaction will be limited by the amount of water vapour in the hole. A by-product of the reaction will be moisture at pH12 which will rapidly react with the high partial pressure of CO2 to produce carbonate encrustation. So it will be a problem to keep the hole clean - unless you prevent any moisture entering the hole from the surface control area. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-07-07T23:34:51.603" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8369" PostTypeId="2" ParentId="8367" CreationDate="2016-07-08T02:54:58.443" Score="6" Body="&lt;p&gt;Photosynthesis has not stopped. It happens all the time, splitting water and carbon dioxide, and producing oxygen and carbohydrates. Likewise, organic matter rots and decomposes all the time, requiring oxygen and releasing carbon dioxide. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Keeling_Curve&quot;&gt;Keeling curve&lt;/a&gt; actually illustrates this quite nicely: most of the land mass where this happens lies in the north, and during the summer photosynthesis dominates whereas in the winter, decomposition dominates. As a result, CO2 concentration in the atmosphere decreases in the northern summer and increases in the northern winter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your question about using up all of the oxygen in the atmosphere by burning all fossil fuels is a good one. If indeed you could get hold of all of the carbon that, over the past 2 billion years, has been separated from the oxygen by photosynthesis, then you could do that. But the carbon is not accessible: only a small fraction is actually in the form of fossil fuels. A much larger part is simply dispersed in the form of organic matter in the sediments of the earth (both on land and in the sea), and it may not be concentrated enough to actually burn by itself. For example, soil has a significant fraction of carbon, but it does not usually burn. More carbon has been subducted in sediments through plate tectonics and now resides dozens or hundreds of kilometers down in the Earth mantle. (A fraction of it will eventually come back out as carbon dioxide in volcanic eruptions).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, most of the carbon that has resulted from photosynthesis is no longer accessible for burning, and consequently not available to react with the atmospheric oxygen.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2016-07-08T02:54:58.443" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="8370" PostTypeId="2" ParentId="8367" CreationDate="2016-07-08T07:16:45.297" Score="4" Body="&lt;p&gt;If I understand it right, you are assuming that in the beginning we had CO&lt;sub&gt;2&lt;/sub&gt;, which was then split to organic carbon and O&lt;sub&gt;2&lt;/sub&gt; via photosynthesis. And now you are asking if it's possible to reverse all of that by burning all organic carbon, so that it consumes the O&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your assumption is not quite right. Oxygen is the most abundant element in Earth's crust and mantle, locked up in rocks. Rocks are made out of mostly oxygen. Atmospheric oxygen is negligible, when looked up in the context of the entire Earth. Oxygen is constantly being consumed and produced by reactions between the atmosphere and the solid Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not only that, there are processes in the Earth that take sediments and pull it down deep into the Earth, in subduction zones. Anything can be subducted: both organic unoxidised carbon and oxidised carbon in the form of carbonates (e.g. limestone). This goes down to tens to several hundreds of kilometres, far away from any interaction with the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an example, let's say that you have a forest which that consumes a certain amount of CO&lt;sub&gt;2&lt;/sub&gt; and H&lt;sub&gt;2&lt;/sub&gt;O, generating organic carbon-hydrogen and releasing the excess O&lt;sub&gt;2&lt;/sub&gt; to the atmosphere. Now you have carbon (and hydrogen) locked up in solids. Some of this organic material burns, decomposes, or otherwise reacts with atmospheric O&lt;sub&gt;2&lt;/sub&gt; to generate CO&lt;sub&gt;2&lt;/sub&gt; and H&lt;sub&gt;2&lt;/sub&gt;O all over again. However, some of it is buried deep in the Earth's crust (that's how we get coal, gas and oil). So in theory, we can extract and mine everything, and then burn it. However, some of it is buried even deeper and is carried down by &lt;a href=&quot;https://en.wikipedia.org/wiki/Subduction&quot; rel=&quot;nofollow&quot;&gt;subduction&lt;/a&gt; to the Earth's mantle. In there, it is far away from our reach and there is no way we can extract it to burn it. So the oxygen generated while producing this organic material lingers in the atmosphere, but the organic material itself is deep below in the mantle, unable to react with any oxygen (as O&lt;sub&gt;2&lt;/sub&gt;, any redox reactions are a different story).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To sum it up, your point of view is too simplistic as it does not take into account the Earth as a whole, but only top soil and atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2016-07-08T12:04:07.833" LastActivityDate="2016-07-08T12:04:07.833" CommentCount="13" ContentLicense="CC BY-SA 3.0" />
  <row Id="8371" PostTypeId="1" AcceptedAnswerId="8373" CreationDate="2016-07-08T08:46:02.043" Score="10" ViewCount="445" Body="&lt;p&gt;In Google Earth we can see some very clear lines in the Sahara.  In the screenshot below you can clearly see these lines starting at the top going southward, then gently curving westward towards the bottom.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are these structures and how were they formed?  Are they related to the wind?  Some sort of flow?  Are they surface structures or they are embedded deep in the rock?  Or something else?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I realize that this may be a trivial question for anyone with some knowledge of geology, but I really wasn't able to google up the answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DahyH.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DahyH.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6276" LastEditorUserId="6298" LastEditDate="2022-02-06T17:29:10.797" LastActivityDate="2022-02-06T17:29:10.797" Title="Large scale structures in the Sahara – what are they?" Tags="|sedimentology|desert|satellite-oddities|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8373" PostTypeId="2" ParentId="8371" CreationDate="2016-07-09T14:27:33.547" Score="10" Body="&lt;p&gt;These features are created by the wind.You will note that the upper left portion has a small dark spot. This is known as Waw al-Namus, or the &quot;Oasis of Mosquitoes.&quot; It has a path of material in the same curved  manner as the surrounding features you mention.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the link provided below:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;However, Waw al-Namus and its plume are not the only &quot;wind records&quot;&#xA;  in the area. As you utilise higher resolution images - of the order of&#xA;  1 km or better, other, somewhat different &quot;long-term wind tracers&quot; are&#xA;  revealed at almost every place across the Sahara Desert. These&#xA;  generally take the form of small-scale, long, parallel thin lines, as&#xA;  if being drawn across the desert by a giant pencil. One of the most&#xA;  spectacular places with long-term wind streamlines imprinted into the&#xA;  landscape can be found further southeast of Waw al-Namus, to the&#xA;  southeast of the Tibesti Mountains.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://oiswww.eumetsat.org/WEBOPS/iotm/iotm/20060115_wind/20060115_wind.html&quot;&gt;http://oiswww.eumetsat.org/WEBOPS/iotm/iotm/20060115_wind/20060115_wind.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6282" LastEditorUserId="6282" LastEditDate="2016-07-10T14:36:00.030" LastActivityDate="2016-07-10T14:36:00.030" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8374" PostTypeId="2" ParentId="8343" CreationDate="2016-07-10T06:04:48.017" Score="1" Body="&lt;p&gt;In developed areas perhaps the most telling evidence of a developing landslide in its early stages are doors and windows that no longer open and close easily and cracks in pavements and curbs that line up to define the boundaries of the slide.&lt;/p&gt;&#xA;" OwnerUserId="6284" LastActivityDate="2016-07-10T06:04:48.017" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8375" PostTypeId="1" AcceptedAnswerId="8536" CreationDate="2016-07-10T07:08:42.677" Score="4" ViewCount="839" Body="&lt;p&gt;I recently visited Japan, where I observed a lenticular cloud above Mount Fuji:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/es9cb.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/es9cb.jpg&quot; alt=&quot;Mount Fuji and lenticular cloud&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Curious by the cloud, I looked it up and found it it's a &lt;a href=&quot;https://en.wikipedia.org/wiki/Lenticular_cloud&quot; rel=&quot;noreferrer&quot;&gt;lenticular cloud&lt;/a&gt;, that forms because of rising moist air coming into contact with cooler air. However, why is it circular? If I would look at it from above would it still be circular? Since air moves in a certain direction, I would expect the cloud to be laminar and elongate towards one direction rather than circular.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What makes it circular?&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-08-09T02:36:18.223" Title="Why are lenticular clouds circular?" Tags="|atmosphere|clouds|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="8376" PostTypeId="1" CreationDate="2016-07-10T20:39:49.617" Score="5" ViewCount="42" Body="&lt;p&gt;I have a dataset of dissolved load (major and trace elements), the associated error is specified as &amp;lt;10% for all the cases, in the same way I have rock analysis (major and trace) with the same analytical error. I applied a very simple model (forward model) in order to apportion the dissolved elements into different sources (basically rain, silicates and carbonates), this model uses the elemental ratios in each source and basic arithmetic operations to sequentially subtract from the river chemistry data the partial contributions from each source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The results are the specific contributions from each source to the overall river chemistry, for example in my case, the silicates contributed with 65% of the dissolved load, carbonates 30% and rain 5%. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am looking for a way (method) to express the uncertainty in this analysis, I have checked some basic error propagation equations, but since no function is defined specifically, I have no clue how to propagate the error. Since all the data I am using has the same analytical error: &amp;lt;10%, I will assume 10% for all the samples. How can I proceed?&lt;/p&gt;&#xA;" OwnerUserId="5820" LastActivityDate="2016-07-10T20:39:49.617" Title="Dealing with uncertainty in source apportionment" Tags="|models|rivers|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8377" PostTypeId="2" ParentId="8343" CreationDate="2016-07-11T00:42:46.293" Score="2" Body="&lt;p&gt;Terrestrial laser scanning (the ground-based version of Lidar) provides very precise mapping of surfaces. This has been used to look for changes in cliff faces and slopes that are precusors to failure.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2016-07-11T00:42:46.293" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8378" PostTypeId="1" CreationDate="2016-07-12T05:12:39.463" Score="2" ViewCount="355" Body="&lt;p&gt;252 million years ago, Earth underwent its worst, most violent chapter in the form of the Permian-Triassic extinction event, or &quot;The Great Dying&quot;.  70% of the terrestrial species and 95% of the marine species became extinct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There was one thing that I had noticed in Permian and Triassic landmasses--both periods had Pangaea, all the world's continents clumped together into one singular landmass.  And recent evidence has found that it took life ten million years to recover from the Great Dying.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So why did it take so long?  Was the damage of the Great Dying that extensive?  Or did Pangaea play a part in delaying the recovery process?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastEditorUserId="87" LastEditDate="2016-07-12T08:10:20.577" LastActivityDate="2016-11-20T14:01:46.267" Title="Recovery From the Great Dying" Tags="|paleontology|mass-extinction|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8379" PostTypeId="2" ParentId="8326" CreationDate="2016-07-12T11:27:47.303" Score="0" Body="&lt;p&gt;The best way to start understanding Mohr Circles is this Youtube Video about stress on an inclined plane:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://youtu.be/qDzE2KkMkE0?list=PL2bYAB99Iq4kp5S6o1XEjMP4BVSwCbpLC&quot; rel=&quot;nofollow&quot;&gt;https://youtu.be/qDzE2KkMkE0?list=PL2bYAB99Iq4kp5S6o1XEjMP4BVSwCbpLC&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From there, check out the other videos of this guy.&#xA;But right: this is an open-end question.&lt;/p&gt;&#xA;" OwnerUserId="6152" LastActivityDate="2016-07-12T11:27:47.303" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8381" PostTypeId="1" AcceptedAnswerId="8383" CreationDate="2016-07-12T17:09:31.980" Score="3" ViewCount="219" Body="&lt;p&gt;I saw a rainbow outside Silverton, CO last week that for a few minutes seemed to show part of the color cycle (red to purple) several times within the same band. This picture is how it looked to my eye. I assume this is some refraction phenomenon of multiple rainbows, or ... ? It was also a double, but that part isn't shown. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/T1VcY.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/T1VcY.jpg&quot; alt=&quot;showed this banding for a few minutes&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I took another picture a few minutes later of it looking normal (the rainbow brightened, the droplets were bigger, and there was a strong double):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gDO69.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gDO69.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is causing this strange banding? &lt;/p&gt;&#xA;" OwnerUserId="6292" LastEditorUserId="5536" LastEditDate="2016-07-25T17:34:03.617" LastActivityDate="2016-07-25T17:34:03.617" Title="Explanation for single rainbow that contained colors several times" Tags="|atmosphere|atmospheric-optics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8383" PostTypeId="2" ParentId="8381" CreationDate="2016-07-12T17:38:23.967" Score="7" Body="&lt;p&gt;It a &lt;a href=&quot;https://en.wikipedia.org/wiki/Rainbow#Supernumerary_rainbows&quot;&gt;supernumerary bow&lt;/a&gt;, which results when the droplets that create the rainbow are very small and of nearly uniform size. The droplets need to be small enough so as to make diffraction a significant effect.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="28050" LastEditDate="2016-07-13T12:58:36.380" LastActivityDate="2016-07-13T12:58:36.380" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8384" PostTypeId="1" CreationDate="2016-07-14T02:52:55.297" Score="9" ViewCount="2699" Body="&lt;p&gt;It always looks like clouds are so much higher in the sky (altitude) in the summer than in the winter. Is that true? If not, is there some sort of optical illusion? If so, why is that?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I live in Iowa, so I don't know if this is a phenomenon that exists in all climates, just temperate climates, or just the US Midwest. And, for that matter if this actually happens or if I'm just misinterpreting what I'm seeing. &lt;/p&gt;&#xA;" OwnerUserId="6297" LastEditorUserId="28050" LastEditDate="2018-01-08T16:33:01.367" LastActivityDate="2018-02-07T17:06:05.610" Title="Is there a seasonal difference in the average cloud floor?" Tags="|meteorology|clouds|seasons|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8385" PostTypeId="1" CreationDate="2016-07-14T13:10:56.120" Score="8" ViewCount="2071" Body="&lt;p&gt;Like a sound wave, there are compressed and dilated regions in the air. But do compressed regions also occur in winds. If one considers squalls, they feel like a compressed region of air. Perhaps they are too great to be considered as a kind of amplitude, but is there anyway a kind of wave in wind?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the other question/answer is not mentioned anything about forming waves. So does wind behave (perhaps only a little bit) with sound-wave compressions and dilations?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="5372" LastEditDate="2016-07-14T18:22:09.670" LastActivityDate="2021-01-21T16:38:05.110" Title="Do winds behave like waves?" Tags="|meteorology|" AnswerCount="4" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8387" PostTypeId="2" ParentId="8385" CreationDate="2016-07-14T14:41:03.657" Score="6" Body="&lt;p&gt;Yes, there are a lot of waves in wind. The wave you may be looking for is called a gravity wave (aka buoyancy wave). To name a few other waves&#xA;Rossby Waves, Gravity Waves, Inertio-Gravity waves, Sound Waves, Kelvin Waves&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am sure there are more than just those few waves out there.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2016-07-14T14:57:26.193" LastActivityDate="2016-07-14T14:57:26.193" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8392" PostTypeId="1" CreationDate="2016-07-15T21:59:28.930" Score="4" ViewCount="781" Body="&lt;p&gt;I have a question I've always been curious about regarding the topic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I understand it, the desalination process is that they take the salt water, create usable water from it and then salt sludge is pumped back out into the ocean.  When I've read about it an issue from this seems to be that the waste is bad to the ecosystem they pump it back into plus that extra salt can't be that good for the ocean as a whole and its inhabitants.  I understand that one plant might not be that much of an impact on the ocean as a whole but if it became more standard and over 50yrs+, especially with the changing climate and droughts maybe it would and there are greater ecological issues.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is:&#xA;Why can't they just pump the salt water into a designated area in the desert?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I live in California and we have plenty of desert and every time I head out toward Las Vegas or travel up north I think about this.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why couldn't some chunk of land be allocated where raw salt water can be pumped into and then let it evaporate?  Wouldn't that just generate more rain which, at least in the winter, create more snow pack in the mountains and help create drinking water more naturally?  The salt and stuff left behind could just stay there and become a salt flat.  At a minimum couldn't they process the water and then pump the sludge into the desert (the remaining water would still evaporate) and it seems to me that would be a better solution than putting it back into the ocean for it to have more salt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If it could be done on a reasonable scale, maybe some land that was once unusable could be terraformed to forest which would help with the climate, pull carbon out of the air, and on a 5 or 10 year cycle the trees can be cut down made into mulch and then new ones planted...  Not the salt water or land where the salt is left but additional land allocation for this (we do have a LOT of desert) and I know sand would need to be cultivated but we also have a lot of cows and organic material we can use to help convert the sand into more usable soil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Running some pipes from a coast inland while posing some logistical challenge doesn't seem unreasonable to me.  Better than oil pipelines...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for the responses&lt;/p&gt;&#xA;" OwnerUserId="6306" LastEditorUserId="6306" LastEditDate="2016-07-15T22:17:36.633" LastActivityDate="2020-10-28T18:59:47.097" Title="Desalination and Weather Impact?" Tags="|meteorology|ocean|desert|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8393" PostTypeId="2" ParentId="8392" CreationDate="2016-07-16T02:23:30.747" Score="3" Body="&lt;p&gt;Your first question, regarding salt pollution requires a back-of-an-envelope calculation. At present, about 4% of the global population relies, either wholly or in part, on desalinated water. Because this is energy intensive, it is also expensive, so such water users are parsimonious, using about 1% of the global domestic water supply. But let us, for the sake of argument, assume that the desalinated option really takes off at some time in the future, perhaps by means of less energy intensive 'forward osmosis'. We will assume that 10% of the current population (7.4 billion people) may eventually use desalinated water, yielding a daily delivery of bitterns with 2.45 x 10^^9 tonnes of salt. Compare this to the 1,5 x 10^^17 tonnes of salt already in the ocean - the salt return would be 0.0000016% of what is already in the sea. Moreover, even this trivial amount would be diluted by the hydrological cycle, because the water that is drunk, used for washing, etc, ultimately returns to the sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But you ask whether the local concentrated saline return would be harmful to the environment? Consider Adelaide, in South Australia, which boasts the largest desalination plant in the southern hemisphere. Very detailed studies, by both computer modelling and direct observation, show that the dispersion of the saline plume reaches concentrations undetectable against the background salinity, within a few hundred metres of the outflow. It certainly hasn't impacted the local marine ecology at all - and the South Australians are very particular about environmental issues!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Again, consider the greatest concentration of desalination plants in the world, in the Arabian Gulf. This shallow-water (&amp;lt;50 metres) Gulf has high natural rates of evaporation, which raises the salinity from the normal 3.6% to about 4.1%. This change is orders of magnitude more than can be attributed to the salinity change from all the desalination plants combined. The ecology and biodiversity of the Gulf is still rich, and not at all affected by local bitterns effluent. Climate change will intensify evaporation, which is much more of a worry than 'desal' plants. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to your second question about changing the climate and increasing rainfall by pumping bitterns into the desert, there is a massive problem with that. As the salinity increases by evaporation, the vapour pressure at the lake surface decreases, which suppresses further evaporation. Since we would be dealing with hyper-saline brines to start with, we would rapidly approach an equilibrium in which the massively decreased evaporation would equal the natural deliquescence of the salt. In fact, evaporation would win, but only slightly. The loss of moisture to the atmosphere would be barely noticeable, and not sufficient to terra-form the down-wind area. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suggest that the impacts of global warming will massively eclipse any trivial changes brought about by evaporation basins. If you don't believe me, I suggest you get some hydrologic and geochemical textbooks, and do some mass-balance calculations of your own.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-07-16T02:23:30.747" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8395" PostTypeId="1" CreationDate="2016-07-16T14:11:26.417" Score="6" ViewCount="65" Body="&lt;p&gt;If you were swimming/floating within a body of water experiencing upwelling due to sea-surface thermal fronts, would you be able to physically feel the water that is being up-welled or is it on a different scale not sensed by humans?&lt;/p&gt;&#xA;" OwnerUserId="5923" LastActivityDate="2016-07-17T02:29:19.293" Title="Can up-welling water at oceanic fronts be physically felt?" Tags="|ocean|oceanography|ocean-currents|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8396" PostTypeId="1" AcceptedAnswerId="8397" CreationDate="2016-07-16T19:51:14.293" Score="4" ViewCount="491" Body="&lt;p&gt;I am quite new to geology and have a realtive dating problem which I am a bit unsure of. I know very well the principle of superposition, principle of cross-cutting, etc., but am still a little bit unsure on one part.  The problem is illustrated in the following picture:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wRo2v.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wRo2v.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is about the intrusion (E).  Obviously the intrusion must have occurred later than the deposits of layers B, C and D, but how can I tell if the intrusion occurred before or after the deposit of layer A?  In my opinon, both of these scenarios are possible.  The intrusion does not appear to cross through A, so I suppose it is possible that A was deposited after the intrusion.  But isn't it also possible that A was deposited before the intrusion, and the intrusion simply did not make it past layer B?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If anyone can let me know if there is any certain way of reasoning whether A or E occurred first, then I would greatly appreciate it.&lt;/p&gt;&#xA;" OwnerUserId="6312" LastEditorUserId="725" LastEditDate="2016-07-16T21:10:59.517" LastActivityDate="2016-07-17T11:47:11.287" Title="Relative dating of intrusion" Tags="|geology|homework|stratigraphy|magmatism|dating|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8397" PostTypeId="2" ParentId="8396" CreationDate="2016-07-16T21:10:37.407" Score="4" Body="&lt;p&gt;It does seem like it's impossible to know unless you have additional information. However, I think there is a hint in there. See this white halo around the intrusion? My guess (and I could be wrong here) is that it's not there for artistic reasons but rather it's there to provide a very strong hint.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My feeling that this is some kind of metamorphosed contact zone (or aureole), which transforms sedimentary rocks into their low pressure and high temperature metamorphic equivalents (shales to hornfels, limestone to marble, sandstone to quartzite, etc).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's hard to see, but I think I can see (when zooming in ) some of the white halo extending into the bottom of layer A. That would mean A was present when E intruded, because you can't metamorphose something that's not there. Otherwise, the metamorphic aureole would be cut by layer A.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jYTnf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jYTnf.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Again, I'm not sure because the image is low resolution. Maybe you should ask your teacher or if that's not possible try to figure out if you should already know about metamorphic contact zones in your stage of geological education.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2016-07-17T11:47:11.287" LastActivityDate="2016-07-17T11:47:11.287" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8398" PostTypeId="2" ParentId="8395" CreationDate="2016-07-17T02:29:19.293" Score="2" Body="&lt;p&gt;There is a sea-surface thermal front at the northwest tip of Scotland. On the western side is water from the Gulf Stream Drift - cool, but sufficiently comfortable to swim in. On the north side is Arctic water which is horribly cold and which nobody in their right mind would swim in. I write from personal experience! &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-07-17T02:29:19.293" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8399" PostTypeId="1" CreationDate="2016-07-17T03:13:41.937" Score="1" ViewCount="188" Body="&lt;p&gt;For example, the towns that has the highest dew point are usually next to the Red Sea and the Persian Gulf where the seawater temperature exceeds 30 degrees in summer.&lt;/p&gt;&#xA;" OwnerUserId="3325" LastActivityDate="2016-09-15T05:06:18.460" Title="How strong is the correlation between the dew point of a town and the seawater temperature next to that town?" Tags="|meteorology|temperature|humidity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8400" PostTypeId="2" ParentId="8399" CreationDate="2016-07-17T04:11:12.590" Score="1" Body="&lt;p&gt;It depends upon location, latitude, sea surface temperature and seasonality, dominant wind direction (offshore / onshore) and what dew point you are measuring - diurnal mean / min / max, mean weekly / monthly/ annual? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't recall anyone ever having asked this question, and I suspect that the answer will be vague and inconclusive. Test a hundred different coastal towns and you will get a hundred different answers. Also, it is time consuming, so do your own research. Numerous databases, which include coastal meteorology sites, will yield dew point data. Sea surface temperatures may not be so easy. I can only speak for Australia where the Bureau of Meteorology has SSTs available on-line. Prepare the two data sets with corresponding dates on an Excel spreadsheet - be careful to maintain exact date correspondence (errors can occur from missing data, systematic errors, transcription errors, and 'February 29th'). Then run the command &quot;=PEARSON&quot; to find the Pearson moment correlation. You could even publish your findings.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-07-17T04:11:12.590" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8401" PostTypeId="1" CreationDate="2016-07-18T08:01:23.027" Score="1" ViewCount="40" Body="&lt;p&gt;I'm trying to wrap my head around water's density, low-compressibillity and bouyancy. Are all these 3 things related, if so, how? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm particularly interested if water's low compresibillity of responsible for the physiological appearance of marine organisims.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, small marine organisms are held by the density of water and as a result have amorphous spherical bodies suspended in a relatively viscous material. On the other hand, larger organisms need to move quickly through dense water and have stream-lined bodies. Consequently, you can deduce an organism's body size simply by looking at their body shape. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or a briefer example, marine mammals' body weight are supported against gravity by the buoyancy of water, hence why oxygen-breathing marine mammals die when stranded as a result of crushing their organs through body weight.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the low-compressibillity of water responsible for these characteristics in marine organisims?  &lt;/p&gt;&#xA;" OwnerUserId="5923" LastActivityDate="2016-07-18T08:01:23.027" Title="is the low-compressibility of seawater responsible for its bouyancy?" Tags="|ocean|oceanography|water|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8402" PostTypeId="1" CreationDate="2016-07-18T08:33:44.940" Score="3" ViewCount="256" Body="&lt;p&gt;I want to calculate recharge for an aquifer for which I have calculated daily ET by Haude's method and I also have daily precipitation data. How can I calculate recharge per minutes. &lt;/p&gt;&#xA;" OwnerUserId="5557" LastActivityDate="2016-07-18T11:20:38.457" Title="Recharge calculation for an aquifer" Tags="|precipitation|evaporation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8403" PostTypeId="1" CreationDate="2016-07-18T08:44:18.103" Score="7" ViewCount="7437" Body="&lt;p&gt;I read that thermohaline circulation is caused by cold and saline water sinking, while warm and less dense water rises. &lt;a href=&quot;http://oceanservice.noaa.gov/facts/coldocean.html&quot;&gt;link&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand that saline water is more dense, as there is a higher mass due to dissolved salts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, decreasing the temperature of water decreases the solubility, so in theory, shouldn't cold water hold less salt than warm water? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Vice-versa, shouldn't warm equatorial water increase in density as it is able to hold more salt?&lt;/p&gt;&#xA;" OwnerUserId="5923" LastActivityDate="2016-07-27T09:04:58.313" Title="Thermohaline: Why is cold and dense seawater salty when warm water holds more dissolved salts?" Tags="|ocean|oceanography|ocean-currents|salinity|thermohaline-circulation|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8404" PostTypeId="2" ParentId="8403" CreationDate="2016-07-18T11:10:20.347" Score="8" Body="&lt;p&gt;Warm water does hold more salt - &lt;em&gt;at saturation&lt;/em&gt;, but seawater isn't even close to saturation. Surface sea water gets warm, starts to evaporate (hence clouds) and therefore gets denser. So it sinks to the ocean floor, where it cools down to about 4 deg Celsius, and gets denser still. But it still is a very long way from being saturated with salt, so 'how much salt the water can hold' doesn't come into it. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-07-18T11:10:20.347" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8405" PostTypeId="2" ParentId="8403" CreationDate="2016-07-18T11:13:13.197" Score="3" Body="&lt;h2&gt;Usual salinity and solubility of NaCl&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;An usual salinity in the world's major oceans is 35 g/kg. The solubility of sodium chloride in water is around 360 g/kg (&lt;a href=&quot;https://en.wikipedia.org/wiki/Sodium_chloride&quot; rel=&quot;nofollow&quot;&gt;Sodium Chloride&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Solubility_table&quot; rel=&quot;nofollow&quot;&gt;Solubility in water&lt;/a&gt;). Therefore, the solubility is not the limiting factor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sea salt consists mainly of sodium chloride (NaCl). Therefore, this approximation should be OK.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Mixing of salt and water&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The salt in the sea water 'moves together' with the water. Thus, when warm water flows from the equator to the poles it transports salt to the poles. At the poles water cools down and sinks (together with salt).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we had a direct relation between sea surface temperature and salinity, in some region we would need a net flux of salt in the opposite direction to the water net flux.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Global salinity gradients&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Global salinity gradients exist. The salinity is above the global mean salinity in some regions -- particularly in warm regions --, whereas in other regions the salinity is below this mean. These salinity gradients are caused by a net loss of oceanic water (evaporation &gt; precipitation + fresh water inflow; enhanced salinity) in warm regions and by a net input of water by (evaporation &amp;lt; precipitation + fresh water inflow; reduced salinity), respectively. These gradients are not related to solubility of salt.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastEditorUserId="5594" LastEditDate="2016-07-27T09:04:58.313" LastActivityDate="2016-07-27T09:04:58.313" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8406" PostTypeId="2" ParentId="8402" CreationDate="2016-07-18T11:20:38.457" Score="2" Body="&lt;p&gt;This methodology won't work. Haude's method only gives a rough estimate of evaporation. Consider the hydrologic cycle: Rainfall = evaporation (or evapotranspiration) + runoff + surface detention + soil moisture storage + infiltration +/- interbasin transfer. It sounds like you don't have nearly enough data to estimate the aquifer recharge. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-07-18T11:20:38.457" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8407" PostTypeId="1" AcceptedAnswerId="8432" CreationDate="2016-07-18T14:02:18.750" Score="5" ViewCount="1426" Body="&lt;p&gt;Does anyone know where there is a detailed definition for tidal harmonic constituents? There is loads of stuff on $M_2$, $S_2$, $N_2$, etc. (all the common ones), but there are a great many more, some (I believe) involved in the calculation of tidal current speeds and directions. I am interested in what their physical significance is and the relationship to earth/moon/sun positions.&lt;/p&gt;&#xA;" OwnerUserId="5958" LastEditorUserId="111" LastEditDate="2016-07-24T13:04:25.617" LastActivityDate="2016-07-24T13:04:25.617" Title="Definitions of tidal harmonic constituents...?" Tags="|ocean|oceanography|sea-level|tides|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8408" PostTypeId="1" CreationDate="2016-07-19T05:05:41.867" Score="4" ViewCount="110" Body="&lt;p&gt;The Ph.D dissertation &lt;a href=&quot;http://d-nb.info/1070584401/34&quot; rel=&quot;nofollow noreferrer&quot;&gt;Assessment of air quality in Northern China by using the&#xA;COSMO-ART model in conjunction with satellite and&#xA;ground-based data &lt;/a&gt; which was written by Stefanie Schrader in KIT German.&lt;/p&gt;&#xA;&lt;p&gt;This thesis did a great job on applying the COSMO-ART in China and quantify the influence of dust plume and anthropogenic aerosol in North China on air quality.&lt;/p&gt;&#xA;&lt;p&gt;The third chapter told about the calibration and validation of the source inventory. I think this chapter is quite essential for further discussion. The conclusion would be useful only if the meteorology condition, source inventory and the primary pollution diffusion, etc could be well reproduced.&lt;/p&gt;&#xA;&lt;p&gt;So, the author choose three different source emission setting for 3 independent run(run A, run B and run C).&lt;/p&gt;&#xA;&lt;p&gt;Three runs were performed for NO, NO2 and ozone. By comparing with observation data, she present the average value and pearson correlation coefficient like the figure below.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RT6kz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RT6kz.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The NO and Ozone simulation results are all in good agreement with observation in  run B and run C. But the NO2 simulation shows negative correlation.  In the thesis, the author said:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot; It can also be seen that correlation coefficients for&#xA;measured and modelled NO2 are overall very low (Table 6), which is mainly determined by a general&#xA;problem of NO2 simulation due to its complex chemical nature&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In my opinion, &lt;strong&gt;NO2 is the essential precursor for ozone formation&lt;/strong&gt;. Ozone is generated by the NOx-VOC-O3 cycle. &lt;strong&gt;But the result here may reveal that the temporal variation of ozone concentration could be represented decent even the NO2 variation can't be performed.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here is an illustration shows the classical ozone and NOx temporal variation.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LtK97.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LtK97.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I present my doubt here and want to hear some knowledge related.&lt;/p&gt;&#xA;&lt;h3&gt;PS: Rewrite my text as a question.&lt;/h3&gt;&#xA;&lt;p&gt;The simulation results from this dissertation for NO, NO2 and O3 performed differently. NO and O3 has a good agreement with the observation data by correlation analysis. But the NO2 temporal variation could not be reproduced(negative r). The author explain this phenomena due to the complex chemical nature of NO2.&lt;/p&gt;&#xA;&lt;p&gt;But in my opinion, the NO2 is essential for O3 formation. How can the O3 variation be reproduced decently even though the true NO2 variation couldn't be reappeared.&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-07-20T01:56:25.840" Title="Correlation analysis with primary air pollutants and secondary formed ozone" Tags="|atmosphere-modelling|atmospheric-chemistry|air-pollution|ozone|air-quality|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8409" PostTypeId="1" AcceptedAnswerId="8411" CreationDate="2016-07-19T06:17:22.973" Score="5" ViewCount="9741" Body="&lt;p&gt;As I know, both divergent boundary and hot spot are formed by rise of magma of convention, but divergent boundary is a line and hot spot is a point, is there difference between 2 kinds of rising magma?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="124" LastEditDate="2016-07-26T05:08:30.770" LastActivityDate="2016-07-26T05:08:30.770" Title="What is difference between divergent boundary and hot spot?" Tags="|geophysics|plate-tectonics|crust|hotspot|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8410" PostTypeId="1" AcceptedAnswerId="8423" CreationDate="2016-07-19T09:22:07.533" Score="3" ViewCount="1349" Body="&lt;p&gt;Apologies in advance for a beginners question. Different rock types make me curious and recently went to an &lt;a href=&quot;https://en.wikipedia.org/wiki/Krk&quot; rel=&quot;nofollow noreferrer&quot;&gt;area&lt;/a&gt; where interesting sedimentary rock is all over. As the area is on the coast, sea has washed away some soil and is making it easy to observe rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This sedimentary rocks is composed of different pieces. Sometimes the pieces are in different color, while other times are white. I took an image of a typical rock:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TB3If.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TB3If.jpg&quot; alt=&quot;sedimentary rock - first view&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/xnCqK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xnCqK.jpg&quot; alt=&quot;sedimentary rock - second view&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How such sedimentary rock is made? In which period of crust formation? Can you point me to links where I can learn more about it?&lt;/p&gt;&#xA;" OwnerUserId="934" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T20:49:40.893" LastActivityDate="2019-08-28T20:49:40.893" Title="How this sedimentary rock is made?" Tags="|rocks|sedimentology|petrology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8411" PostTypeId="2" ParentId="8409" CreationDate="2016-07-19T09:22:54.133" Score="5" Body="&lt;p&gt;&lt;strong&gt;Divergent boundaries occur at the boundary between plates&lt;/strong&gt;. A divergent boundary is where two tectonic plates are actively being &lt;em&gt;pushed apart&lt;/em&gt;. Divergent boundaries create rift valleys on land and eventually ridges on ocean floors, where hotter material wells up from the mantle, cools and form new crust. For example, the East African Rift Valley (a divergent boundary), is pushing apart the African plate, separating Somalia from the continent. Eventually the rift valley will flood, producing a ocean between the newly split plates with the East African Rift becoming a mid-ocean ridge.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/m35YH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/m35YH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Hot-spots, or &lt;em&gt;mid-plate&lt;/em&gt; tectonic activity, occur away from boundaries between plates&lt;/strong&gt;. A hot-spot is where a &lt;em&gt;plate is moving over&lt;/em&gt; a stationary &lt;em&gt;mantle plume&lt;/em&gt;. Hot-spots are responsible for island-chains, such as those seen in Hawaii, which form as the plate slides over the plume or even volcanoes on land, like Yellowstone. The islands of Hawaii lie thousands of kilometres away from the boundaries of the Pacific plate on which they sit. A nice feature is that the Hawaiian island chain lies in a north-westerly line that matches the direction the Pacific plate is moving. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qnBI8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qnBI8.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main thing to keep in mind is that divergent boundaries occur at the boundaries of plates. Hot-spots occur in the middle of plates, often thousands of kilometres away from the boundaries of the plates. &lt;/p&gt;&#xA;" OwnerUserId="5923" LastEditorUserId="5923" LastEditDate="2016-07-20T11:38:38.080" LastActivityDate="2016-07-20T11:38:38.080" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8412" PostTypeId="1" CreationDate="2016-07-19T12:51:08.287" Score="4" ViewCount="571" Body="&lt;p&gt;For debris flow,  Flow-R and Titan2D I'm sure are very good, both the softwares themselves and the amount of publications.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But for rock falls, it seems the Colorado Rockfall Simulation Program is not supported anymore. And from this &lt;a href=&quot;http://geotechpedia.com/Software/Tag/1548/rockfall&quot; rel=&quot;nofollow&quot;&gt;list&lt;/a&gt;, it is the only one that is free. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, for rock falls it would be good to have a software  that makes 3D simulations, using DEMs, like &lt;a href=&quot;http://www.ecorisq.org/ecorisq-tools&quot; rel=&quot;nofollow&quot;&gt;RockyFor3D&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="6323" LastEditorUserId="595" LastEditDate="2016-07-19T13:56:59.080" LastActivityDate="2016-07-19T13:56:59.080" Title="Which are the best open/free softwares for debris flow and rock fall simulation?" Tags="|natural-disasters|software|simulation|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8414" PostTypeId="2" ParentId="8384" CreationDate="2016-07-19T20:27:59.707" Score="1" Body="&lt;p&gt;Cloud base varies as response to several factors, normally, cloud bases are lower in the wintertime than during the summer, particularly for stratus clouds. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cloud development is mostly dependent on temperature and the amount of water vapor in the air. The temperature has to be low enough to cause the air to become saturated. If the air is relatively dry, a colder temperature is required for water vapor to condense into water droplets. During winter, the temperature of the air in the lower part of the atmosphere is lower than during the summer, so stratus clouds can usually form at somewhat lower heights during the winter than during the summer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a generalization that does not hold true under all conditions and at all times. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also some more regional patterns can be present since the differentiation between Summer and Winter can be difficult to establish, for example in the tropics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Taken from: &lt;a href=&quot;https://stab-iitb.org/newton-mirror/askasci/wea00/wea00274.htm&quot; rel=&quot;nofollow&quot;&gt;https://stab-iitb.org/newton-mirror/askasci/wea00/wea00274.htm&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5820" LastEditorUserId="5820" LastEditDate="2016-07-20T16:28:56.347" LastActivityDate="2016-07-20T16:28:56.347" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8415" PostTypeId="1" AcceptedAnswerId="8421" CreationDate="2016-07-19T20:44:46.500" Score="0" ViewCount="3039" Body="&lt;p&gt;&lt;em&gt;Loosely related to the question&lt;/em&gt; &lt;a href=&quot;https://earthscience.stackexchange.com/q/4876&quot;&gt;Will the ocean eventually erode all land?&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How long will it take for the ocean to erode &lt;a href=&quot;https://en.wikipedia.org/wiki/Rockall&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rockall&lt;/a&gt; (an uninhabited granite islet within the exclusive economic zone of the United Kingdom)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BW4KT.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BW4KT.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the assumption that plate tectonics is paused. (If you know that plate tectonics will carry rockal below the waves before it erodes please do mention this in your answer!)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand that the rate and size of storms will have an effect, both of which are unpredictable, therefore I am more than happy with an order of magnitude indication.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have any sources to back up numbers you've used in calculations, such as the rate of erosion of the basalt, that would be great, as I would love to do some further research.&lt;/p&gt;&#xA;" OwnerUserId="6330" LastEditorUserId="595" LastEditDate="2016-07-20T06:41:58.893" LastActivityDate="2016-07-20T09:36:02.400" Title="How long will it take for the ocean to erode Rockall?" Tags="|geology|rocks|erosion|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8416" PostTypeId="2" ParentId="8410" CreationDate="2016-07-19T20:58:15.207" Score="1" Body="&lt;p&gt;I would not say there is any one answer of how sedimentary rocks are formed, they are a wide class of rocks, and certainly they were not formed in one period, in fact they are still regularly forming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The class includes sand stones, mud stones, lime stones, concretions as you show, and many other forms.  Basically they are sediments (thus the name) that pile up and fuse or bond through chemical reactions, pressure or other reaction and form larger composites. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A fair starting point is Wikipedia:  &lt;a href=&quot;https://en.wikipedia.org/wiki/Sedimentary_rock&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Sedimentary_rock&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On your particular pictures, that would be fairly typical or a glacial gravel deposit, riverbed deposits or even a landslide which was then filled in with silt and other deposits which fused into a cement or limestone encasing the gravel.&lt;/p&gt;&#xA;" OwnerUserId="6178" LastEditorUserId="5594" LastEditDate="2016-07-20T06:40:07.097" LastActivityDate="2016-07-20T06:40:07.097" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8417" PostTypeId="2" ParentId="8090" CreationDate="2016-07-20T03:42:36.950" Score="1" Body="&lt;p&gt;There is also the &lt;code&gt;net&lt;/code&gt; function in the &lt;a href=&quot;https://cran.r-project.org/web/packages/RFOC&quot; rel=&quot;nofollow&quot;&gt;RFOC&lt;/a&gt; package&lt;/p&gt;&#xA;" OwnerUserId="6333" LastActivityDate="2016-07-20T03:42:36.950" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8418" PostTypeId="1" CreationDate="2016-07-20T05:17:09.963" Score="3" ViewCount="6456" Body="&lt;p&gt;I have temperature, u wind, v wind and relative humidity. I am wondering to calculate water vapor flux divergence and convergence. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would anybody kindly help to find our a solution for this? &lt;/p&gt;&#xA;" OwnerUserId="3194" LastEditorUserId="3194" LastEditDate="2017-02-14T00:49:59.783" LastActivityDate="2023-07-14T14:36:18.043" Title="How to calculate water vapor flux divergence from temperature, relative humidity, u wind and v wind?" Tags="|meteorology|water-vapour|moisture-flux|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8419" PostTypeId="1" CreationDate="2016-07-20T07:54:44.630" Score="0" ViewCount="517" Body="&lt;p&gt;As I know, due to Coriolis force, hurricane in each hemisphere can spin in one direction only. But I also know hurricane can be formed near equator, which colriolis force is weak. My question is, is it possible that a vortex spinned in opposite direction is developed into hurricane near equator?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastActivityDate="2016-07-20T08:33:13.323" Title="Can a hurricane with different spinning direction be formed accidently?" Tags="|tropical-cyclone|" AnswerCount="1" CommentCount="1" ClosedDate="2016-07-21T00:46:46.930" ContentLicense="CC BY-SA 3.0" />
  <row Id="8420" PostTypeId="2" ParentId="8419" CreationDate="2016-07-20T08:33:13.323" Score="1" Body="&lt;p&gt;No, a small vortex in a contrary rotation might develop into something larger if conditions were right, and there was no horizontal shear, but it wouldn't last long. The Coriolis force would work against it, and it would fizzle out. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, hurricanes don't form near the equator - there isn't enough horizontal rotation to kick-start it. Hurricanes initiate a little to the north or south of the equator. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-07-20T08:33:13.323" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8421" PostTypeId="2" ParentId="8415" CreationDate="2016-07-20T09:36:02.400" Score="3" Body="&lt;p&gt;Impossible to give an accurate answer because nobody has ever studied rates of erosion of this kind of rock in such a setting. Typical long-term rates of cliff cut-back in an exposed position are 5 to 20 cm per year, but that is for average rock, which is much softer than Rockall. This is a complex rock, mainly comprising Aegirine Granite, and containing some unique minerals. I'm guessing that the combination of sea salt corrosion, frequent wetting and drying, and chemically aggressive leachate from all that guano will result in a rate of chemical erosion of 0.5 to 5.0 mm per year. Let us say 2 mm per year - a high value but under the extreme circumstances, certainly plausible.  Given that the rock is only about 25 metres along the lesser axis, and that chemical and weathering attack will occur on all sides, that should give a 'demolition rate' of about 6000 to 7000 years. But that's only chemical erosion. There is also the physical erosion to consider. None of the photographs I have seen give a good impression of the potential for basal abrasion. What your photograph does indicate however is that there are eroding oblique fractures. These will facilitate sea water and wave ingress which will eventually fragment the rock and accelerate its demise. Overall I would be very surprised if there is anything left above the waves in 4000 to 5000 years from now. Even without erosion, climate change is likely to raise sea level at least 7 metres by that time, in which case it may completely disappear in as little as 2000 to 3000 years. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-07-20T09:36:02.400" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8422" PostTypeId="2" ParentId="8418" CreationDate="2016-07-20T20:43:04.183" Score="7" Body="&lt;p&gt;The formula for moisture flux is $$q\vec{V} $$ &#xA;where $q$ is the water vapor mixing ratio, which can be found using &lt;a href=&quot;http://www.ncl.ucar.edu/Document/Functions/Built-in/mixhum_ptrh.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;mixhum_ptr&lt;/a&gt; and $\vec{V}$ is the velocity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore the divergence of the moisture flux must be &#xA;$$\nabla{\dot{}q\vec{V}}=\frac{\partial(qu)}{\partial x}+\frac{\partial(qv)}{\partial y}+\frac{\partial(qw)}{\partial z} $$&#xA;$$\approx\frac{\delta(qu)}{\delta x}+\frac{\delta(qv)}{\delta y}+\frac{\delta(qw)}{\delta z}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;which is computable if you have gridded data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, you could compute this by setting&#xA;$$qu=q\ast u$$ $$qv=q\ast v$$ $$qfluxDiv=uv2dv\_cfd(qu,qv,lat,lon,opt) $$&#xA;Use uv2dv_cfd per &lt;a href=&quot;http://www.ncl.ucar.edu/Document/Functions/Built-in/uv2dv_cfd.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.ncl.ucar.edu/Document/Functions/Built-in/uv2dv_cfd.shtml&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: If you wanted the turbulent moisture flux, you would need to subtract $\nabla{\dot{}\bar{\vec{V}}\bar{q}}$ from your answer.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2016-11-01T14:14:30.680" LastActivityDate="2016-11-01T14:14:30.680" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="8423" PostTypeId="2" ParentId="8410" CreationDate="2016-07-20T23:50:19.447" Score="3" Body="&lt;p&gt;The rock you show is a conglomerate - it contains a substantial amount of clasts (your pieces) that are gravel or larger size. The pieces have been cemented together into a new rock - kind of like concrete.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are a couple of additional things that can be seen in your pictures. First the clasts are very angular. This means they haven't been rounded be wave action or transport to the location where the rock formed. It was very likely formed close to where you found it. If you look at the clasts, the grey ones look like the rock to the lower left and the light ones seem similar to the rock to the lower right. This suggests that the conglomerate formed by eroding those rock types followed by cementation very close to the source. Then a new phase of erosion formed the pieces you see. &lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2016-07-20T23:50:19.447" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8424" PostTypeId="1" CreationDate="2016-07-21T12:19:35.827" Score="1" ViewCount="445" Body="&lt;p&gt;While researching across the Australian Earthquake Engineering Society archive about &lt;a href=&quot;http://www.aees.org.au/category/seismology/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seismology&lt;/a&gt;, I came across an earthquake map of the Australian island state of Tasmania (below):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/z6Fco.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/z6Fco.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am aware that Australia experiences intraplate earthquakes, so I am not surprised the earthquakes occurring. However, what I am wondering is, &lt;strong&gt;is there a geological explanation for the hook-like pattern of earthquakes occurring off the north-east coast of Tasmania?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user6341" LastActivityDate="2016-10-20T20:17:32.770" Title="Tasmanian earthquake patterns" Tags="|seismology|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8425" PostTypeId="2" ParentId="8424" CreationDate="2016-07-21T13:53:59.350" Score="1" Body="&lt;p&gt;I can't prove it, but I strongly suspect that most, if not all, of the earthquakes in that north-south lineation along the eastern Bass Strait are caused by slumping of sediments in a series of listric faults. That whole continental edge is a very thick heap of deltaic and continental sediments of about Kimmeridgian (late Jurassic)to late Eocene age. There is a brief summary in: &lt;a href=&quot;https://www.researchgate.net/publication/240419988_Submarine_canyons_of_the_continental_margin_East_Bass_Strait_Australia&quot; rel=&quot;nofollow&quot;&gt;Submarine canyons of the continental margin, East Bass Strait (Australia).&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to 'the hook', it is surely no coincidence that this exactly coincides with 'Flinders Canyon', which you can see on Google Earth. What you can't make out on G.E. is the enormous size of the Canyon and its sedimentary catchment area. The sediments here are up to about 3 kilometers thick, and a massive submarine amphitheater funnels sediment into the canyon in periodic surges. I would bet a month's beer money that the 'hook earthquakes' were caused by occasional turbidite collapses of sediment down this steep canyon. The magnitudes, location, slope and approximate frequency are all spot on. &#xA;If you include the smaller canyons along the same continental edge then it is estimated that some 80,000 to 90,000 cubic kilometers of sediment have collapsed from this continental edge since the Late Eocene, i.e. over the last 40 million years. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="6093" LastEditDate="2016-07-22T09:10:09.220" LastActivityDate="2016-07-22T09:10:09.220" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8426" PostTypeId="1" AcceptedAnswerId="8438" CreationDate="2016-07-22T05:58:23.740" Score="4" ViewCount="218" Body="&lt;p&gt;In a volcanic eruption, magma rushes to the 'outside' of the Earth. Does this mean the size of Earth also increases? If not, how is the volume left after the magma rushed out refilled?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="595" LastEditDate="2016-07-22T10:06:45.470" LastActivityDate="2016-07-23T01:17:23.707" Title="Does the size of Earth increase due to volcanism?" Tags="|volcanology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8427" PostTypeId="2" ParentId="8426" CreationDate="2016-07-22T07:13:08.273" Score="0" Body="&lt;p&gt;In one word: No. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let me explain with the help of a water filled balloon. Here water is a proxy for the magma in the earth, and the balloon surface afor the earth crust.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you puncture the balloon, water will come out (similar to lava). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whenever volcanism happens the total mass on the surface of earth does not change. &lt;br /&gt;&#xA;Since the molten rock is equivalent to a liquid, no cavity remains inside the earth (think of the water filled balloon).&lt;br /&gt;&#xA;Here the total mass is constant, which implies that the earth size should not increase or decrease. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However. the picture is not the same since volcanism causes heat loss as well!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth is constantly loosing heat by various means and volcanism is one of them. As you you know: the colder the material, the more it contracts. So we can say it helps in contracting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Note:&lt;/strong&gt; There are radiogenic materials (Uranium, thorium, etc) which cause energy production in the mantle and thus expand the material volume. Hence there is a kind of equilibrium  maintained for the transient time. On an earth scale this time could be of tens of thousands years.&lt;/p&gt;&#xA;" OwnerUserId="5413" LastEditorUserId="595" LastEditDate="2016-07-22T09:34:59.757" LastActivityDate="2016-07-22T09:34:59.757" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8428" PostTypeId="1" CreationDate="2016-07-22T10:33:52.997" Score="2" ViewCount="223" Body="&lt;p&gt;Different textbooks use different terminologies when discussing the same chemical compounds, for example when discussing the minerals...&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Elements / Compounds  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;em&gt;Sulfide minerals consist of metallic elements in chemical combination with the element sulfur&lt;/em&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;em&gt;Phosphate are a group of minerals of one or more metallic elements chemically associated with the phosphate compound PO4&lt;/em&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Ions  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;em&gt;Sulfide ions (S$^2$-) bond with a number of positive ions to form the sulfides&lt;/em&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;em&gt;Phosphorous in the form of phosphate ions (PO4$^3$-) binds with positive ions to form the phosphate minerals&lt;/em&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Are element/compounds and ions the same thing?&lt;br&gt;&#xA;If they are the same, why the two terms?&lt;br&gt;&#xA;Which is better terminology?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm just after a basic understanding of how elements form rocks and being able to differentiate between this terminology is beyond my layman abilities. &lt;/p&gt;&#xA;" OwnerUserId="5923" LastEditorUserId="5923" LastEditDate="2016-07-22T11:13:07.907" LastActivityDate="2016-07-22T11:13:07.907" Title="Ions &amp; elements, which is the correct terminology to use when discussing chemical compounds in Earth Science?" Tags="|geology|geochemistry|rocks|mineralogy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8429" PostTypeId="2" ParentId="8428" CreationDate="2016-07-22T10:53:15.447" Score="3" Body="&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Elements are just one specific type of atom. Magnesium, oxygen, sulfur, etc. These are all elements.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Compounds are several different types of atoms (that is, elements) bonded together. For example, magnesium oxide (MgO), or iron sulfide (FeS).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Ions are charged atoms or compounds (also known as &lt;em&gt;species&lt;/em&gt; in some cases). Ions can be monoatomic (consisting of only one atom, or element) or polyatomic (consisting of more than one type of atom). Cations are positively charged (like Ca&lt;sup&gt;2+&lt;/sup&gt;) and anions are negatively charged (like O&lt;sup&gt;2-&lt;/sup&gt;). Polyatomic ions that occur in geological contexts are usually anions, with carbonate (CO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt;) and sulfate (SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt;) being two good examples.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;All ions are elements (or combination of them). Not all elements are ions. We geologists and geochemists use these terms interchangeably all the time. I think that using ions may be slightly better, particularly in the case of sulfur. Because sulfur in minerals can be either in sulfate or sulfide form, just saying &quot;sulfur&quot; gives little information. The properties of sulfate and sulfide minerals are completely different, so it's actually useful to know.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Sulfide ions (S2-) bond with a number of positive ions to form the sulfides&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not strictly correct, because the bonding in many sulfide minerals is a combination of covalent and metallic bonding, and it only has a little ionic character. Still, even in cases when the bonding is not ionic (such as in sulfide minerals), we still often talk of them of ions because it's convenient and easy.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Sulfide minerals consist of metallic elements in chemical combination with elemental sulfur&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This statement is not correct. When we speak of &quot;elemental&quot; elements, we mean that they are monoatomic compounds (or minerals). In the case of sulfur, it will be the yellow sulfur mineral. Gold, copper and silver and other example of &quot;elemental&quot; minerals. Once the sulfur is bonded to other metals, it is no longer elemental. It is part of a sulfide mineral.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-07-22T10:53:15.447" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="8430" PostTypeId="1" CreationDate="2016-07-22T12:40:53.507" Score="1" ViewCount="29" Body="&lt;p&gt;I'm thinking of visiting South America at some stage, to look at some interesting geology in the Atacama, Patagonian Andes, etc. Does anyone know where the best geological museum is in South America? I have a particular fancy to see what unusual lithologies South America has to offer.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-07-22T12:40:53.507" Title="South American Rocks" Tags="|petrology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8431" PostTypeId="2" ParentId="8424" CreationDate="2016-07-22T13:16:50.623" Score="1" Body="&lt;p&gt;Almost all of the earthquakes in that area are associated to an earthquake sequence between 1883-1892 (some are described for example in: Michael-Leiba, 1989). The seismicity did not cease after 1892, the largest recorded earthquake in Tasmania in the 20th century happened in the same region (Michael-Leiba and Jensen, 1993)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you tinker around with the &lt;a href=&quot;http://www.ga.gov.au/earthquakes/searchQuake.do&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geoscience Australia earthquake database&lt;/a&gt; no such pattern is visible, the following map shows the 73 earthquakes M&gt;3 around Tasmania which happened between 1955 and today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LqCAA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LqCAA.png&quot; alt=&quot;Map of earthquakes&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://d28rz98at9flks.cloudfront.net/81241/Jou1989_v11_n1_p089.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Michael-Leiba, 1989: Macroseismic effects, locations and magnitudes of some early Tasmanian earthquakes. Journal of Australian Geology &amp;amp; Geophysics, 11, 89-99&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://d28rz98at9flks.cloudfront.net/81331/Jou1993_v13_n4_p369.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Michael-Leiba &amp;amp; Jensen, 1993: The West Tasman Sea (Flinders Island) earthquake of 14 September 1946. Journal of Australian Geology &amp;amp; Geophysics, 13, 369-372&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2861" LastEditorUserId="2861" LastEditDate="2016-10-20T20:17:32.770" LastActivityDate="2016-10-20T20:17:32.770" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8432" PostTypeId="2" ParentId="8407" CreationDate="2016-07-22T14:02:39.887" Score="6" Body="&lt;p&gt;The explanation of all the tidal constituents is pretty complex because of the interactions between the different frequencies involved. The harmonic analysis is an expansion of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Theory_of_tides&quot;&gt;Equilibrium Theory of Tides&lt;/a&gt; into a set of harmonic terms. The list of relevant periods includes:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the lunar day (period of lunar rotation), 24.84 mean solar hours.&lt;/li&gt;&#xA;&lt;li&gt;the sidereal month (period of lunar declination), 27.32 mean solar days. &lt;/li&gt;&#xA;&lt;li&gt;the tropical year (period of solar declination), 365.24 mean solar days. &lt;/li&gt;&#xA;&lt;li&gt;the period of the lunar perigee, 8.85 years (1 year = 365.2421988 days). &lt;/li&gt;&#xA;&lt;li&gt;the period of the lunar node, 18.61 years.&lt;/li&gt;&#xA;&lt;li&gt;the period of the solar perihelion, 20940 years.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The frequency of any tidal constituent can be computed by a combination of small numbers that multiply each of the periods (usually they are expressed as speeds, e.g., degrees per mean solar hour) above. The most complete algebraic expansion of the constituents was produced by &lt;a href=&quot;https://en.wikipedia.org/wiki/Arthur_Thomas_Doodson&quot;&gt;Doodson&lt;/a&gt; in 1921. The set of small numbers are called Doodson numbers and represent the importance of each of the period in the specific constituent. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For instance, the set of Doodson numbers for the $M_2$ is (2,0,0,0,0,0), with the ”2” referring to &quot;twice per lunar day&quot; and the rest of the terms are zero (no influence). This is expected as the $M_2$ represents the passage of the same point on Earth through the &quot;tidal bulge&quot;, created by the tidal forces, twice in a lunar day. The set of Doodson numbers for the $O_1$ is (1,-1,0,0,0,0), which represents 1 cycle/lunar day minus 1 cycle/tropical month. This is the result of the inclination between the Earth's axis and the Moon's orbit that causes the &quot;tidal bulge&quot; to be offset from the Equator and thus a point on Earth will experience one single absolute maximum per day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The explanation of the lesser tidal constituents become rather tricky as the combination of Doodson numbers increases. For instance, $MSN_2$ is a combination of lunar, solar, and nodal influences and has a set of Doodson numbers of (2,3,-2,-1,0,0) making the interpretation rather complex. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;While a list of origins of the constituents can be found (e.g., Table 4.1 in &lt;a href=&quot;http://nora.nerc.ac.uk/119157/1/sea-level.pdf&quot;&gt;Pugh, 1996&lt;/a&gt;), ultimately it is simpler to try to understand each constituent as the result of a harmonic (~ Fourier expansion) decomposition, rather than a complex interaction between the bodies and their periods.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A few good books dealing with the analysis of tides are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Pugh, D. T. (1996). &lt;a href=&quot;http://nora.nerc.ac.uk/119157/1/sea-level.pdf&quot;&gt;Tides, surges and mean sea-level&lt;/a&gt;. John Wiley &amp;amp; Sons Ltd. (check Table 4.1 for a list of constituents and their origin).&lt;/li&gt;&#xA;&lt;li&gt;Godin, G. (1972). The analysis of tides, 264 pp. University of Toronto.&lt;/li&gt;&#xA;&lt;li&gt;Kowalik, Z., &amp;amp; Luick, J. (2013). &lt;a href=&quot;https://www.google.com/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=2&amp;amp;cad=rja&amp;amp;uact=8&amp;amp;ved=0ahUKEwjzpoe8nYfOAhXDHT4KHUxjAAAQFggjMAE&amp;amp;url=https%3A%2F%2Fwww.uaf.edu%2Ffiles%2Fsfos%2FKowalik%2Ftide_book.pdf&amp;amp;usg=AFQjCNHHGKUACmRcTov5kfXi-rJkZE_0SA&amp;amp;sig2=Pki8QsuXs8OWhjzxUGErqw&amp;amp;bvm=bv.127521224,d.cWw&quot;&gt;The Oceanography of Tides&lt;/a&gt;. University of Alaska Fairbanks.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="111" LastActivityDate="2016-07-22T14:02:39.887" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8433" PostTypeId="1" CreationDate="2016-07-22T14:30:47.460" Score="6" ViewCount="59" Body="&lt;p&gt;Imagine I set off an airgun in the ocean and I measure the far-field signature.&lt;br /&gt;&#xA;Then I do the same thing shortly after introducing tiny gas bubbles into the water, and mixing them well. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there measurements of the Q factor for the mixed phase?&lt;/p&gt;&#xA;" OwnerUserId="6349" LastEditorUserId="595" LastEditDate="2016-07-23T00:42:34.547" LastActivityDate="2016-07-24T17:54:40.333" Title="Seismic attenuation in mixed gas/water" Tags="|seismology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8434" PostTypeId="1" CreationDate="2016-07-22T15:24:51.720" Score="1" ViewCount="49" Body="&lt;p&gt;I am trying to find a relationship between the silicate-rich rocks weathering products. For example I've found information regarding gabbro weathering in which, according the consulted source, in 100 grams of weathered gabbro, 46.61 g will form laterite  and the remaining 53.39 will be dissolved. In this case the ratio between the leftover and the dissolved part will be 0.87, my idea is to determine a range of ratios for silicate-rich rocks (igneous) for which these relations might be valid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone know about more sources where I can find more information regarding the relation between the relationships between the dissolved and the leftovers of weathered rocks, with emphasis in silicate-rich rocks (igneous)?&lt;/p&gt;&#xA;" OwnerUserId="5820" LastActivityDate="2016-07-22T15:24:51.720" Title="Weathering of silicates" Tags="|geochemistry|rocks|water|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8435" PostTypeId="1" AcceptedAnswerId="8437" CreationDate="2016-07-22T16:10:00.070" Score="4" ViewCount="189" Body="&lt;p&gt;There is a wikipedia page on &lt;a href=&quot;https://en.wikipedia.org/wiki/Glacier_growing&quot; rel=&quot;nofollow&quot;&gt;glacier growing&lt;/a&gt;, and also a &lt;a href=&quot;http://www.umb.no/statisk/noragric/publications/master/2007_ingvar_tveiten.pdf&quot; rel=&quot;nofollow&quot;&gt;Master thesis&lt;/a&gt; has apparently been written on the subject, investigating this practice in Northern Pakistan.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the one hand, I have read (I'm a physicist, I know next to nothing about glaciers!) that glaciers are highly nonlinear systems, displaying strong hysteresis effects. On the other hand, I would expect that relevant time scales for glacier growth are more in the hundreds of years and not decades.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, I would love to know if this is practice is scientifically grounded in any way?&lt;/p&gt;&#xA;" OwnerUserId="6351" LastActivityDate="2016-07-22T21:12:46.333" Title="Is glacier growing a hoax?" Tags="|glaciology|ice|glacier|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8436" PostTypeId="1" CreationDate="2016-07-22T17:03:40.177" Score="5" ViewCount="690" Body="&lt;p&gt;Currents are formed in 3 major ways: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Tidal Currents&lt;/li&gt;&#xA;&lt;li&gt;Wind-driven Currents&lt;/li&gt;&#xA;&lt;li&gt;Thermohaline circulation&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I've seen the gulf stream mentioned as both a wind-driven surface current and being part of the thermohaline circulation, which is due to density differences. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does the gulf stream belong to both classifications of currents?  &lt;/p&gt;&#xA;" OwnerUserId="5923" LastEditorUserId="111" LastEditDate="2016-07-24T12:45:42.167" LastActivityDate="2016-07-28T02:06:11.083" Title="Is the gulf stream both a wind-driven current and part of thermohaline circulation?" Tags="|ocean|oceanography|ocean-currents|thermohaline-circulation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8437" PostTypeId="2" ParentId="8435" CreationDate="2016-07-22T20:45:35.873" Score="7" Body="&lt;p&gt;There is a decent explanation in &lt;a href=&quot;http://science.sciencemag.org/content/326/5953/659&quot; rel=&quot;noreferrer&quot;&gt;Glacier Man&lt;/a&gt; &lt;em&gt;Science&lt;/em&gt; 30 Oct 2009:&#xA;Vol. 326, Issue 5953, pp. 659-661. (&lt;a href=&quot;http://www.ldeo.columbia.edu/res/pi/tcn/Lamont_Cosmogenic_Nuclide_Lab/References_files/Artifical_Glacier_adaption_Nepal_Science.pdf&quot; rel=&quot;noreferrer&quot;&gt;alternative link&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Norphel’s idea was to divert the lost winter&#xA;  water from its course down the mountain,&#xA;  along regularly placed stone embankments&#xA;  that would slow it down and allow it to spread&#xA;  and trickle across a large, shaded surface&#xA;  depression a few hundred meters from the village.&#xA;  Here, the slowed water would freeze and&#xA;  pack into a glacier that would begin melting&#xA;  when the sun rose high enough in spring to&#xA;  expose the thick ice&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;...&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Norphel has built nine glaciers since that&#xA;  first one, which he began in the late 1980s&#xA;  and worked on until 1994. They average&#xA;  250 meters long by 100 meters wide; the&#xA;  Phuktse glacier remains the largest. Norphel&#xA;  estimates that each one provides some 6 million gallons (23,000 cubic meters) of water,&#xA;  although there has been no accurate analysis to&#xA;  date, and the undulating ground makes it difficult to guess the volume of ice in each glacier.&#xA;  Each artificial glacier is built using local&#xA;  labor and materials for about 3 to 10 lakh&#xA;  Indian rupees (6000 to 20,000 US dollars),&#xA;  depending on the size and site, compared&#xA;  with about US$34,000 for a cement water&#xA;  reservoir, Norphel says.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Personally, I wouldn't call these glaciers.  It is more that water is being dammed so it freezes rather than runs off, and stays frozen into the spring then eventually melts before the end of the season.  &lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2016-07-22T21:12:46.333" LastActivityDate="2016-07-22T21:12:46.333" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8438" PostTypeId="2" ParentId="8426" CreationDate="2016-07-23T01:17:23.707" Score="5" Body="&lt;p&gt;This is actually a more complicated question than it seems on the surface (no pun intended). The short answer is that the volume vacated by the magma is eventually refilled by the very tectonic processes that filled it in the first place. Crust is subducted, molten, and then rises to fill magma chambers. The process goes on and on. In some cases the plate that was being subducted eventually disappears (this will happen to the Juan de Fuca plate in a few million years), and the volcanoes associated with become extinct, not dormant but extinct. But generally speaking, volcanism is an ongoing process; the Earth is constantly recycling crustal material&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2016-07-23T01:17:23.707" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8439" PostTypeId="1" CreationDate="2016-07-23T11:18:10.873" Score="2" ViewCount="1363" Body="&lt;p&gt;I am doing a research on earthquakes but I cannot fully understand what causes earthquakes.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Caused by a sudden releases of energy by the Earth's crust, causing&#xA;  seismic waves which causes the ground to shake.&quot;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&quot;Energy release associated with rapid movement on active faults is the&#xA;  cause of most earthquakes.&quot;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&quot;Earthquakes are usually caused when rock underground suddenly breaks&#xA;  along a fault. This sudden release of energy causes the seismic waves&#xA;  that make the ground shake.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I have been puzzled by these statements and I really can't seem to understand.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do these mean that energy is released by the earth's crust then produces seismic waves, then the seismic waves make the ground shake?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does it also mean that earthquakes often most on faults because the release of energy and seismic waves occurs near or on a fault?&lt;/p&gt;&#xA;" OwnerDisplayName="user6354" LastActivityDate="2016-07-27T19:15:37.287" Title="Seismology: What causes an earthquake?" Tags="|seismology|earthquakes|crust|" AnswerCount="1" CommentCount="6" ClosedDate="2016-08-05T15:16:19.200" ContentLicense="CC BY-SA 3.0" />
  <row Id="8443" PostTypeId="1" CreationDate="2016-07-24T19:49:10.460" Score="2" ViewCount="108" Body="&lt;p&gt;Which influence does the constellation of the continents have on the global climate? Was the biosphere more susceptible to climatic effects a volcanic eruption may cause during the Permian than it is today? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We know that eruptions of volcanoes can influence the global climate and we know that during the Permian period the continents drifted together to a supercontinent extending from the South Pole along the meridian almost to the North Pole. At such a constellation of the land mass, it's imaginable that an eruption of a volcano may have triggered a chain of effects which caused a change of the global climate which was different than we could expect in our current environment. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any evidences from a palaeontological point of view that such a concentration of the land mass strengthened the rise of the global temperature (which probably killed many species) after the release of greenhouse gas a volcano might have caused? &lt;/p&gt;&#xA;" OwnerUserId="6360" LastActivityDate="2016-07-24T19:49:10.460" Title="volcanic effects on the climate during Pangaea" Tags="|geology|climate|climate-change|paleoclimatology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8444" PostTypeId="1" AcceptedAnswerId="8475" CreationDate="2016-07-24T21:53:06.267" Score="4" ViewCount="328" Body="&lt;p&gt;Just to build up on &lt;a href=&quot;https://earthscience.stackexchange.com/questions/8367/why-cannot-people-burn-all-the-atmospheric-oxygen&quot;&gt;my previous success&lt;/a&gt; with oxygen origin in the atmosphere, I want to expand the question as was advised in the answers. The official heresy, despite denied in the comments and answers here, says that &lt;a href=&quot;https://en.wikipedia.org/wiki/Geological_history_of_oxygen&quot; rel=&quot;nofollow noreferrer&quot;&gt;the atmosphere oxygen was produced by plants&lt;/a&gt;. Meantime, the oxidation of the atmosphere was delayed by oxidation of the iron, which was free at that time. Yet, if we look at the geology, we find very few Fe oxides in the crust. There is much more aluminium oxide Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; (aka clay) and quartz (SiO&lt;sub&gt;2&lt;/sub&gt; aka sand). I wonder, when did the clay with sand were formed so that no phytoplankton was necessary for their formation and why was iron delayed its oxidation? &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;PS I have later realized that &lt;a href=&quot;https://earthscience.stackexchange.com/questions/8487/why-limestone-formation-was-not-a-concern-in-atmosphere-oxidation-event&quot;&gt;Ca oxidation is also an issue of this kind&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6272" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-07-30T06:49:29.447" Title="Why is Great Oxidation Event associated with Iron oxidation but not Aluminum or Silicon?" Tags="|geology|earth-history|crust|oxygen|great-oxidation-event|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8445" PostTypeId="2" ParentId="7949" CreationDate="2016-07-24T23:17:14.227" Score="1" Body="&lt;p&gt;I do not have access to the article you cite for the deep subsurface neutron flux but I question whether either article will be particularly useful. The shallow water and soil article is concerned with neutrons in the atmosphere and these attenuate so won't be significant at depth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The major neutron source at depth are spontaneous fission of U-238 and α-n reactions from U and Th series alpha decay. So your flux will be highly dependent on the amount of uranium and thorium and the presence of light elements that will undergo the α-n reaction. This means that the flux will likely be very different from the Broken Hill ore deposit. You may want to look at the literature on subsurface Cl-36 production for flux estimates, but I'm unaware of any dealing with coal deposits. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In coal the C-14 production will be dominated by neutron capture on C-13. Nitrogen n-p should be insignificant because of it's low abundance. I think the n-p reaction depends on higher energy neutrons produced in the atmosphere (but check that).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming you know or can bound the neutron flux then you can estimate the C-14 from the neutron capture cross section of C-13 - 1.4 mb (Chart of the nuclides 16th ed) and the half life of C-14 - 5715 years, assuming steady-state.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2016-07-24T23:17:14.227" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8446" PostTypeId="1" AcceptedAnswerId="8459" CreationDate="2016-07-24T23:45:48.667" Score="3" ViewCount="10190" Body="&lt;p&gt;I am from (and live in) Minnesota, USA. In the summer here it always reaches temperatures in the 90s (F) for periods of time but not every week. The humidity is often high and the dew point often tropical.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My wife is from Guangdong province in the south east region of China. The temperature there most closely resembles Florida, USA. It is usually in the 90s during the summer instead of sometimes. It is always humid and feels tropical.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My wife, her friends and family routinely comment on how incredibly hot it is in China. They say people often don't even go outside because it's so hot. They say it is not like Minnesota, but much worse.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question then... how? Is this merely perception of growing up in a tropical environment without artificial climate control or is there science that backs up their claims? If our regions are the same air temperature with similar humidity and dew points, I don't understand how it can feel so much hotter there.&lt;/p&gt;&#xA;" OwnerUserId="6362" LastEditorUserId="5536" LastEditDate="2016-07-26T18:22:28.180" LastActivityDate="2020-07-22T17:40:11.840" Title="Is it hotter in different places with the same air temperature?" Tags="|climate|temperature|humidity|" AnswerCount="4" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8448" PostTypeId="2" ParentId="8385" CreationDate="2016-07-25T07:13:51.163" Score="2" Body="&lt;p&gt;Roughly, every 12 hours one side of the earth faces the sun while the other does not. And vice versa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Roughly, every 6 months, depending on where you are on Earth, it gets cold or it warms up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a very primitive model but, in essence, some natural phenomena (including some types of winds) behave like a wave because the forcing is wave like.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are waves everywhere in nature. The tides. The Jet Stream. The El-Niño (Rossby wave). The global ocean conveyor belt. They are all waves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding the second part of the question, sound propagation is much faster than the waves we are talking about here. These waves are driven by gravity (and coriolis) so they are typically slow in comparison to the speed of sound. In fact, when we study this phenomena we typically omit acoustic effects.&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2016-07-25T07:19:36.613" LastActivityDate="2016-07-25T07:19:36.613" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8450" PostTypeId="5" CreationDate="2016-07-25T08:05:24.270" Score="0" Body="&lt;p&gt;Use the software tag whenever you refer to software in a generic sense (not specific packages). This will usually be when you are looking for software to do X.&lt;/p&gt;&#xA;" OwnerUserId="595" LastEditorUserId="595" LastEditDate="2016-07-25T18:02:39.007" LastActivityDate="2016-07-25T18:02:39.007" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8451" PostTypeId="4" CreationDate="2016-07-25T08:05:24.270" Score="0" Body="Use when looking for software" OwnerUserId="595" LastEditorUserId="595" LastEditDate="2016-07-25T13:47:25.643" LastActivityDate="2016-07-25T13:47:25.643" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8453" PostTypeId="2" ParentId="2437" CreationDate="2016-07-25T12:27:12.530" Score="1" Body="&lt;p&gt;Also, for a very simple visualization application for plate tectonics and a lot of other information, you can use &lt;a href=&quot;http://www.hhmi.org/biointeractive/earthviewer-online-and-downloadable-version&quot; rel=&quot;nofollow&quot;&gt;EarthViewer&lt;/a&gt;. It is extremely intuitive and the related Earth History data helps to frame the changes.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2016-07-25T12:27:12.530" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8454" PostTypeId="2" ParentId="8446" CreationDate="2016-07-25T13:45:25.403" Score="5" Body="&lt;p&gt;While perceptions about the climate can have an effect on how we react to our environment, Guangdong and Minnesota are fundamentally different climates altogether. Using the Koppen-Geiger climate classification system, Minnesota is mostly a Temperate Continental (Dfb/Dwb) climate, meaning that is has warm summers and long cold winters, while Guangdong is a Humid Subtropical (Cfa/Cwa) climate with hot and wet summers and a short dry winter. The classification is largely based on monthly average temperatures and precipitations based on climate normals (~30-year periods).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It might be the case that temperatures match up at some points, but based on the classifications/geography of both areas, it would seem that Guangdong experiences more humidity and much longer warm periods, which combined would raise the Humidex (&lt;a href=&quot;https://en.wikipedia.org/wiki/Humidex&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Humidex&lt;/a&gt;) above that of Minnesota.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For more information on the Koppen-Geiger classification, &lt;a href=&quot;https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5536" LastActivityDate="2016-07-25T13:45:25.403" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8455" PostTypeId="5" CreationDate="2016-07-25T14:12:31.947" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2016-07-25T14:12:31.947" LastActivityDate="2016-07-25T14:12:31.947" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8456" PostTypeId="4" CreationDate="2016-07-25T14:12:31.947" Score="0" Body="The cultivation of food and materials, specifically from or derived from plants and animals using traditional or modern industrial practices. " OwnerUserId="5536" LastEditorUserId="5536" LastEditDate="2016-07-25T20:19:21.897" LastActivityDate="2016-07-25T20:19:21.897" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8457" PostTypeId="2" ParentId="8343" CreationDate="2016-07-25T15:54:17.417" Score="2" Body="&lt;p&gt;I'm not sure if this is the scope you're looking for but a large portion of site analysis using GIS is to examine potential risks of natural disasters. Mass wasting risk maps based on topographical and soil characteristics as well as extreme precipitation events is a pretty standard research topic. Using fuzzy/boolean multi-criteria analysis, determining areas of potential landslide risk can be ascertained.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some example methodologies for determining landslide risk in different locations:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://link.springer.com/article/10.1007/s12665-009-0245-8&quot; rel=&quot;nofollow&quot;&gt;http://link.springer.com/article/10.1007/s12665-009-0245-8&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://link.springer.com/article/10.1007/s11069-016-2157-8&quot; rel=&quot;nofollow&quot;&gt;http://link.springer.com/article/10.1007/s11069-016-2157-8&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S1110982314000209&quot; rel=&quot;nofollow&quot;&gt;http://www.sciencedirect.com/science/article/pii/S1110982314000209&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="5536" LastActivityDate="2016-07-25T15:54:17.417" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8458" PostTypeId="1" CreationDate="2016-07-25T19:22:49.930" Score="2" ViewCount="127" Body="&lt;p&gt;The basic understanding of ocean currents is that warm currents carry moisture whereas cold currents carry nutrients.  This is why some scientists believe in the connection between the Arctic ice caps and the warm Gulf Stream and the frigid Humboldt and Benguela currents turning the tropical lands of Chile and Namibia bone-dry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With that, there are some confusions with the workings of coldwater ocean currents.  Antarctica is surrounded by the Antarctic Circumpolar Current, a coldwater current, yet it is covered in mile after mile of frozen water.  The Pacific coast of North America is nurtured by coldwater currents, yet we see temperate rainforests.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what's going on?  Why are there habitats that require a lot of moisture near coldwater ocean currents that can't carry that much?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastEditorUserId="4985" LastEditDate="2016-07-29T01:45:35.580" LastActivityDate="2016-07-29T01:45:35.580" Title="Making Sense of Coldwater Ocean Currents" Tags="|ocean-currents|ecology|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="8459" PostTypeId="2" ParentId="8446" CreationDate="2016-07-25T22:47:10.153" Score="5" Body="&lt;p&gt;A temperature is a temperature but the effect of that temperature is not always the same.  Some things that add to our perception include sun intensity, wind, humidity, and simply what we are used to.  The Humidex as mentioned by Trevor, or some other forms of heat indexes are attempts to measure how the temperature feels as compared to what it actually is, and its effects on animals and plants, very similarly to wind chill charts in the winter.  In Minnesota, you should relate to not all temperatures of -10 being created equal, that how hard the wind is blowing matters too.  The temperature is the same, but the cooling effect when the wind is blowing harder is much greater so it feels colder and the damaging effects of the cold can occur much more quickly.  The same is true on the other side, with higher heat indexes at the same air temperature, animals and plants can suffer heat damage more quickly.  &lt;/p&gt;&#xA;" OwnerUserId="6178" LastActivityDate="2016-07-25T22:47:10.153" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8460" PostTypeId="1" CreationDate="2016-07-04T19:03:54.157" Score="8" ViewCount="217" Body="&lt;p&gt;The idea is to melt the fine-grain portion of basalt regolith using a large Fresnel lens, and let it cool to a solid. The lens would track along a tamped bed of material leaving a molten puddle something like 2 cm thick. This would be done on top of more regolith with the same characteristics - which means some of the material would sink into the stuff below and get mixed. Then it is left to cool to a solid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The conjecture is that Fresnel lenses, and the equipment needed to create flat beds of tamped powder regolith and track such lenses across it, is so light that it could be a good way of creating construction materials. If they aren't very good materials they could make up for that in the simplicity of making them and the possibility of making enough that the fact they have weaknesses doesn't matter - just use more.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What might the material yielded by such a process be like?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;hr&gt;&#xA;Edit: Since someone asked, this could yield thin basalt objects of any 2D shape, or objects built up of various layers into 3D shapes. Such objects can be joined with more molten basalt and parged to form continuous rock walls, floors, and arches. An approach to excavation also based largely on the use of lenses (for trenching, and boring for the placement of explosive micro-charges) is used to create voids that are then lined with rock this way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is explained more &lt;a href=&quot;http://moonwards.com/index.html#sketchfab&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, and here is the current model of the equipment:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MKLrF.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MKLrF.jpg&quot; alt=&quot;Lunar Melt in place bed with lenses&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4858" OwnerDisplayName="kim holder" LastEditorUserId="725" LastEditDate="2016-07-26T10:09:47.697" LastActivityDate="2016-07-26T10:09:47.697" Title="Melting basalt on the lunar surface - what would the resulting material be like?" Tags="|geochemistry|planetary-science|moon|magmatism|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="8461" PostTypeId="2" ParentId="8460" CreationDate="2016-07-26T10:09:27.633" Score="3" Body="&lt;p&gt;Melting lunar dust of basaltic composition will result (unsurprisingly) in basalt lava. There might be some volatile loss - if for some reason the basalt had some H&lt;sub&gt;2&lt;/sub&gt;O or CO&lt;sub&gt;2&lt;/sub&gt; trapped in the solid you will most likely lose it. It's probably not going to change its chemical properties much though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On Earth, as lava cools down fast, for example when it's erupted underwater, or when it's the top of a lava flow in contact with air, it quenches to volcanic glass. When it cools down slower, there is enough time for small crystalline material to form in it. These are usually tiny crystals in the μm size. On the Moon, I reckon the lava would cool down slightly slower than on Earth (since there is no air to conduct away heat), but since you're talking about a lava layer which is only 2 cm thick I'm pretty sure it will cool down fast enough for the formation of glass, and any crystalline portion of it will be negligible. I am not sure whether it will crack or not. From my own experience of melting rocks, when you have a similar amount cooling down in Earth's atmosphere, they crack. But then, silicate glass does not crack when cooled down in air. I guess it comes down to the composition of the rock/glass.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The lava will not percolate down to the regolith. Lavas hardly penetrate soils on Earth, so it is probably not going to happen on the Moon where the gravity is much weaker.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I were looking for construction materials on the Moon, I would just build a quarry. Seems easier than melting down dust.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-07-26T10:09:27.633" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8462" PostTypeId="5" CreationDate="2016-07-26T12:48:36.110" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2016-07-26T12:48:36.110" LastActivityDate="2016-07-26T12:48:36.110" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8463" PostTypeId="4" CreationDate="2016-07-26T12:48:36.110" Score="0" Body="For questions pertaining to land and waters above 60 degrees North." OwnerUserId="5536" LastEditorUserId="5536" LastEditDate="2016-07-26T20:33:14.843" LastActivityDate="2016-07-26T20:33:14.843" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8464" PostTypeId="5" CreationDate="2016-07-26T12:50:39.587" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2016-07-26T12:50:39.587" LastActivityDate="2016-07-26T12:50:39.587" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8465" PostTypeId="4" CreationDate="2016-07-26T12:50:39.587" Score="0" Body="For questions that concern the topographic characteristics or landforms present on the floor of lakes, rivers, and other bodies of water." OwnerUserId="5536" LastEditorUserId="5536" LastEditDate="2016-07-26T19:46:24.523" LastActivityDate="2016-07-26T19:46:24.523" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8466" PostTypeId="5" CreationDate="2016-07-26T12:55:55.893" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2016-07-26T12:55:55.893" LastActivityDate="2016-07-26T12:55:55.893" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8467" PostTypeId="4" CreationDate="2016-07-26T12:55:55.893" Score="0" Body="The process of translating spatially organized knowledge of an area or place into a geographic medium. Can include the production of physical/paper maps and atlases, geocoded data, or interactive virtual maps produced using Geographic Information Systems (GIS)." OwnerUserId="5536" LastEditorUserId="5536" LastEditDate="2016-07-26T19:46:19.757" LastActivityDate="2016-07-26T19:46:19.757" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8468" PostTypeId="5" CreationDate="2016-07-26T15:03:07.867" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2016-07-26T15:03:07.867" LastActivityDate="2016-07-26T15:03:07.867" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8469" PostTypeId="4" CreationDate="2016-07-26T15:03:07.867" Score="0" Body="For questions that are concerned with or nested within the field of Geography; the study of lands, their features, and the relationships and complexities between and among peoples, the physical environment, and ecosystems." OwnerUserId="5536" LastEditorUserId="5536" LastEditDate="2016-07-26T20:33:02.327" LastActivityDate="2016-07-26T20:33:02.327" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8470" PostTypeId="5" CreationDate="2016-07-26T15:06:56.760" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2016-07-26T15:06:56.760" LastActivityDate="2016-07-26T15:06:56.760" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8471" PostTypeId="4" CreationDate="2016-07-26T15:06:56.760" Score="0" Body="Questions that concern the health and safety of people, the environment, and ecosystems. Topics can include natural resource and energy efficiency, environmental protection and/or remediation, and environmental best practices." OwnerUserId="5536" LastEditorUserId="5536" LastEditDate="2016-07-26T20:32:52.387" LastActivityDate="2016-07-26T20:32:52.387" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8473" PostTypeId="1" CreationDate="2016-07-27T00:22:35.603" Score="2" ViewCount="537" Body="&lt;p&gt;I've heard meteorologists say that the cold air masses that reach South America during the winter months don't originate in the polar region.  I always thought they crossed the strait of Drake and reached the continent at Tierra del Fuego. From there, depending on their strength, they might reach very low latitudes.  If these cold air masses don't come from Antarctica, where do they come from?&lt;/p&gt;&#xA;" OwnerUserId="6370" LastEditorUserId="6370" LastEditDate="2018-04-21T00:23:49.127" LastActivityDate="2018-04-21T00:23:49.127" Title="How do cold air masses reach South America?" Tags="|meteorology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8474" PostTypeId="1" CreationDate="2016-07-27T06:10:09.413" Score="1" ViewCount="45" Body="&lt;p&gt;I want to estimate infiltration in a soil. What kind of parameters should I be measuring in the field?&lt;/p&gt;&#xA;" OwnerUserId="5557" LastEditorUserId="94" LastEditDate="2016-07-27T07:23:59.063" LastActivityDate="2016-07-27T07:23:59.063" Title="What field data do I need for the Green-Ampt infiltration Model?" Tags="|hydrology|soil|agriculture|hydrogeology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8475" PostTypeId="2" ParentId="8444" CreationDate="2016-07-27T10:38:53.707" Score="6" Body="&lt;p&gt;Because Al and Si were already oxidised to begin with.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the Earth formed, it had some amount of metals (Fe, Si, Mg, Al, Ca, etc) and a fixed amount of oxygen to bond with those metals. Certain metals with bond with oxygen preferentially. Mg and Ca are usually the first to take up oxygen, followed by Al, Si, and then Fe comes last (out of the short list I just provided). Turns out that there is not enough oxygen left for all of the Fe!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you probably know, Fe oxides come in two states, ferrous iron (Fe&lt;sup&gt;2+&lt;/sup&gt;) and ferric iron (Fe&lt;sup&gt;3+&lt;/sup&gt;). So to put it simply, the amount of oxygen left in the Earth after being used up in the other more-easily-oxidised metals was enough to oxidise just a small part of the Fe&lt;sup&gt;0&lt;/sup&gt; to Fe&lt;sup&gt;2+&lt;/sup&gt;. That's why Earth has a metal core - that's where all of the Fe&lt;sup&gt;0&lt;/sup&gt; is. The crust, however, had only Fe&lt;sup&gt;2+&lt;/sup&gt; in it. Once you start pumping out oxygen to the atmosphere, this Fe&lt;sup&gt;2+&lt;/sup&gt; starts oxidising to Fe&lt;sup&gt;3+&lt;/sup&gt;, which is the stable form of iron in the Earth's surface in the presence of oxygen (as you can tell by iron rusting everywhere quite rapidly). This buffers the amount of oxygen you had in the atmosphere until you run out of Fe&lt;sup&gt;2+&lt;/sup&gt; and then oxygen can really increase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some corrections:&#xA;Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; is not clay. It is an important component of clay minerals, but it is definitely not clay. Clay minerals have both Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; and SiO&lt;sub&gt;2&lt;/sub&gt; in it.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-07-27T10:38:53.707" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8476" PostTypeId="2" ParentId="8042" CreationDate="2016-07-27T18:21:12.920" Score="2" Body="&lt;p&gt;Blowholes are formed through small openings in the ground through which air will blow out or suck in.They have been likened to natural fans or vacuums.Blowholes are dependent on weather: air temperature and pressure interact to create the stunning effects when air travels from higher to lower density. When outside air warms up, it may eventually become the same density as air underground, causing air flow at the blowhole to stop.This outside air continues to warm up, causing air to begin blowing out of the hole.&lt;/p&gt;&#xA;" OwnerUserId="6373" LastActivityDate="2016-07-27T18:21:12.920" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8477" PostTypeId="2" ParentId="8439" CreationDate="2016-07-27T19:15:37.287" Score="2" Body="&lt;p&gt;A lot of stress is accumulated along the fault by the time it breaks. For example, on the San Andreas, the Pacific plate is moving north with respect to the North American plate, but the fault resists this motion. As a result, a ton of elastic energy builds up around the fault as the stress increases. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Eventually, the stress becomes so much that the fault slips. The fault slipping releases the stored elastic energy, some of which is radiated as seismic waves. (Most of the energy becomes heat.) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seismic waves &quot;carry&quot; stress and motion. When a wave first arrives, the rock at that location experiences a change in stress. This causes the rock at that spot to move slightly. But then, the rock at that spot has moved with respect to nearby rock. This differential motion of the rock creates stress, which then affects nearby rock similarly. So, the wave's stresses propagates motion in the rock, and motion in the rock propagates stress. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A few types of waves exist (P waves, S waves, and surface waves, in descending order of wave propagation speed). But the general idea behind them all is the same.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ground therefore shakes when the waves arrive.&lt;/p&gt;&#xA;" OwnerUserId="40" LastActivityDate="2016-07-27T19:15:37.287" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8478" PostTypeId="2" ParentId="8473" CreationDate="2016-07-28T01:26:55.883" Score="1" Body="&lt;p&gt;The Pacific coast of South America is affected by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Humboldt_Current&quot; rel=&quot;nofollow&quot;&gt;Humboldt Current&lt;/a&gt;, a wind-driven &quot;upwelling&quot; system running counterclockwise that is cold and windy but nutrient rich..&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &quot;six o'clock&quot; position indeed touches Antarctica, and then the right edge of the &quot;clock&quot; reaches Chile, Peru, Ecuador, and Colombia, as far north as the Galapagos Islands near the equator, making those areas cooler than equivalent latitudes on the Atlantic coast.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason the currents don't &quot;originate&quot; in the Antarctica is because they are part of a circular system that spans a whole ocean in the southern hemisphere. But they &quot;make stops&quot; there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ocean and atmosphere mutually interact to create a &quot;coupled&quot; system that brings about the so-called &lt;a href=&quot;http://www.bom.gov.au/climate/enso/history/ln-2010-12/ENSO-what.shtml&quot; rel=&quot;nofollow&quot;&gt;ENSO&lt;/a&gt; El Nino (La Nina) Southern Oscillation, with its characteristic weather changes.&lt;/p&gt;&#xA;" OwnerUserId="42" LastEditorUserId="42" LastEditDate="2016-07-28T16:49:57.857" LastActivityDate="2016-07-28T16:49:57.857" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="8479" PostTypeId="2" ParentId="8458" CreationDate="2016-07-28T01:48:47.230" Score="1" Body="&lt;p&gt;The currents run counterclockwise. That's why the &lt;a href=&quot;https://en.wikipedia.org/wiki/Humboldt_Current&quot; rel=&quot;nofollow&quot;&gt;Humboldt Current&lt;/a&gt; cools the Pacific coast of South America, because the water is coming from the &quot;six o'clock&quot; position in the Antarctica. But in the Northern Hemisphere, the &quot;six o'clock&quot; position is warm water near the equator, which warms Oregon and Washington.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the northern hemisphere, the cold Labrador current cools land to its &lt;em&gt;west.&lt;/em&gt; That's because the water is coming from the &quot;12 o'clock position near the Arctic. On the other hand, the west coast benefits from &lt;em&gt;warm&lt;/em&gt; water currents running in a counterclockwise direction. That's because the &quot;6 'oclock&quot; position in the northern hemisphere is near the tropics, which brings warm water to Washington and Oregon at the &quot;2-3 o'clock&quot; position.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All other things being equal, colder air carries less moisture than warm air, and land near cold water currents is dryer than land near warm water currents.&lt;/p&gt;&#xA;" OwnerUserId="42" LastEditorUserId="42" LastEditDate="2016-07-28T23:24:31.033" LastActivityDate="2016-07-28T23:24:31.033" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8480" PostTypeId="2" ParentId="8436" CreationDate="2016-07-28T02:06:11.083" Score="1" Body="&lt;p&gt;Yes.&lt;a href=&quot;https://en.wikipedia.org/wiki/Thermohaline_circulation&quot; rel=&quot;nofollow&quot;&gt;Thermohaline circulation&lt;/a&gt; is dependent on differences in water density, caused by differences in temperature and salinity between different bodies of water. It therefore requires deepwater areas, of which the northern and middle Atlantic have the most, for these differences or &quot;gradients&quot; to form. These are influences on the Gulf Stream.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition, the Gulf Stream is wind driven, as is true of most currents. So it depends on &lt;em&gt;both&lt;/em&gt; influences.&lt;/p&gt;&#xA;" OwnerUserId="42" LastActivityDate="2016-07-28T02:06:11.083" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8482" PostTypeId="1" CreationDate="2016-07-28T06:54:33.360" Score="4" ViewCount="1652" Body="&lt;p&gt;Over at &lt;a href=&quot;https://history.stackexchange.com/questions/31049/what-made-port-arthur-manchuria-a-better-port-for-russia-than-vladivostok&quot;&gt;SE History&lt;/a&gt; we're pondering the relation of temperature to Russian motives in establishing its Port Arthur colony in the late 1800's.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wikipedia says that &lt;a href=&quot;https://en.wikipedia.org/wiki/Vladivostok&quot; rel=&quot;nofollow noreferrer&quot;&gt;Vladivostok&lt;/a&gt; is cold due to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Siberian_High&quot; rel=&quot;nofollow noreferrer&quot;&gt;Siberian High&lt;/a&gt;. Meanwhile, in my answer, I repeated what I learned decades ago in my high school earth science class about ocean currents and why Port Arthur was warmer. (&lt;a href=&quot;https://en.wikipedia.org/wiki/L%C3%BCshunkou_District&quot; rel=&quot;nofollow noreferrer&quot;&gt;Port Arthur&lt;/a&gt; was located near the modern large city of &lt;a href=&quot;https://en.wikipedia.org/wiki/Dalian&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dalian&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another astute SE member in the comments pointed out that trade winds are more responsible than ocean currents for weather effects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the truth for these two places? (Note that we are asking more about Winter than summer, as both places would make fine summertime 19th century ports) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, was Vladivostok significantly colder 120 years ago than it is now?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wj4hr.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wj4hr.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2516" LastEditorUserId="-1" LastEditDate="2017-04-13T12:47:54.077" LastActivityDate="2016-08-28T02:24:44.187" Title="Why is Vladivostock so cold, while Dalian is so warm?" Tags="|meteorology|climate-change|ocean-currents|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8484" PostTypeId="2" ParentId="8482" CreationDate="2016-07-28T16:52:50.957" Score="2" Body="&lt;p&gt;Vladivostok (this is the spelling I've always seen) is located at 43º08'  N whereas Dalian lies at 38º05' N.   Five degrees make a difference.  Also, Vladivostok gets more influence from the cold Oyashio current than does Dalian.  For these reasons summers are warmer in Dalian and winters are colder in Vladivostok.  &lt;/p&gt;&#xA;" OwnerUserId="6370" LastEditorUserId="6370" LastEditDate="2016-07-28T20:38:42.353" LastActivityDate="2016-07-28T20:38:42.353" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8486" PostTypeId="2" ParentId="643" CreationDate="2016-07-29T07:32:20.703" Score="-1" Body="&lt;p&gt;Looking down from the North Pole, it spins anti-clockwise: &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_rotation&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Earth%27s_rotation&lt;/a&gt;. The spin is a relic from the angular momentum of the primordial cloud which became our solar system. If the lunar impact hypothesis is correct, this would have been altered significantly at the time.&lt;/p&gt;&#xA;" OwnerUserId="6380" LastActivityDate="2016-07-29T07:32:20.703" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8487" PostTypeId="1" AcceptedAnswerId="8490" CreationDate="2016-07-29T12:36:30.917" Score="1" ViewCount="353" Body="&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/8444/why-is-great-oxidation-event-associated-with-iron-oxidation-but-not-aluminum-or&quot;&gt;I have just got to know&lt;/a&gt; why Fe was a problem. After clay (alumnum) and Silicon got oxidized, there has left a lot of unoxidized Fe in the crust, whose oxidization has finished during GOE. But, ferrum was not the only consumer of the oxygen. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I look at the upper layer of the soil&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pVhnM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pVhnM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;you will see a lot of CaCO3 (aka limestone or calcite) and oxidized aluminum Al2O3 (aka the clay) with sand below it. Nowhere you will see the (oxidized) Ferrum in noticeable amounts. How could Fe be the major consumer of the oxygen despite calcite is present in much larger amounts?&lt;/p&gt;&#xA;" OwnerUserId="6272" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-07-30T02:33:07.153" Title="Why limestone formation was not a concern in atmosphere oxidation event?" Tags="|limestone|oxygen|great-oxidation-event|" AnswerCount="1" CommentCount="5" ClosedDate="2016-08-01T08:17:27.370" ContentLicense="CC BY-SA 3.0" />
  <row Id="8488" PostTypeId="1" AcceptedAnswerId="8489" CreationDate="2016-07-29T23:45:16.637" Score="1" ViewCount="130" Body="&lt;p&gt;&lt;em&gt;Everyone always says that there has always been, and always will be, the same amount of water on planet Earth.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What about space travel?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They obviously need water in space, so they must take it up with them. Take the International Space Station: astronauts must survive up there for around 6 months. And yes, I know they have ways to recycle it, but it must eventually be &quot;refreshed&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that it makes the only teeniest, smallest of differences (a few hundred gallons taken from billions of gallons), but could that phrase be proved wrong?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks in advance!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: I put this on the Earth Science SE because I couldn't find anywhere else it would fit.&lt;/p&gt;&#xA;" OwnerUserId="6385" LastActivityDate="2017-02-18T02:47:10.467" Title="Amount of Earths water with consideration to space travel?" Tags="|atmosphere|water|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8489" PostTypeId="2" ParentId="8488" CreationDate="2016-07-30T02:20:28.603" Score="6" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Everyone always says that there has always been, and always will be, the same amount of water on planet Earth.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Your premise is wrong. The surface and atmosphere of the Earth keeps gaining and losing water all the time. I have no idea where is that coming from, but no scientists say the amount of water is constant.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The Earth's atmosphere is &lt;a href=&quot;http://phys.org/news/2016-07-curious-case-earth-leaking-atmosphere.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;leaking gas to space&lt;/a&gt;. This includes mostly hydrogen gas, which is a major component of water, and also some minor amounts of molecular water.&lt;/li&gt;&#xA;&lt;li&gt;Earth is &lt;a href=&quot;http://elements.geoscienceworld.org/content/12/3/165&quot; rel=&quot;nofollow noreferrer&quot;&gt;gaining&lt;/a&gt; water (and a bunch of other stuff) from meteorites and dust hitting the Earth. Dust accounts for the majority of the mass flux to the Earth.&lt;/li&gt;&#xA;&lt;li&gt;The Earth's surface and atmosphere are getting huge amount of water from volcanic eruptions. H&lt;sub&gt;2&lt;/sub&gt;O is the major component of volcanic gas in most volcanic eruptions.&lt;/li&gt;&#xA;&lt;li&gt;Earth is losing water to the mantle in subduction zones and in lithified sediments.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;All of these water mass fluxes are orders of magnitude larger than the amount of water carried to the international space station. It's like asking whether you can deplete a beach from sand by taking single sand grains out of it, when you're gaining and lose huge amounts of sand by ocean wave action.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2017-02-18T02:47:10.467" LastActivityDate="2017-02-18T02:47:10.467" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8490" PostTypeId="2" ParentId="8487" CreationDate="2016-07-30T02:33:07.153" Score="5" Body="&lt;p&gt;First, let me clarify this again:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/8475/725&quot;&gt;&lt;strong&gt;Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; is not clay.&lt;/strong&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now, back to topic. You are mixing apples and oranges here. The geological section you are referring it was deposited 2 billion years after the GOE. This was long &lt;strong&gt;after&lt;/strong&gt; all surface iron was oxidised, and abundant oxygen was present in Earth's atmosphere.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Nowhere you will see the (oxidized) Ferrum in noticeable amounts&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Iron is not present in this geological section, but it is present elsewhere. You are looking at one specific section in one specific locality on Earth's surface. It is flawed logic to infer what you are based on this.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;How could Fe be the major consumer of the oxygen despite calcite is present in much larger amounts?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Because at this stage, neither calcium nor iron were &amp;quot;consumers&amp;quot; of oxygen. Oxygen has been consumed before, and then this consumption stopped once all of the iron was oxidised. This is why oxygen today exists in the Earth's atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;From the comments:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;@Pont The layer is younger, it is basically made of oxides. A terrible amount of oxides appeared after the GOE but their formation did not delay the atmosphere oxidisation the way free Fe did.&lt;/p&gt;&#xA;&lt;p&gt;I have checked the chemistry. Calcium + water gives me hydroxide. It will exchange CO2 for H2O to from the limestone. This suggests that we still consume Oxygen from the atmosphere. Which pre-oxidization are you talking about?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Metallic calcium probably never existed in the Earth at all. The GOE was a process in which only iron was oxidised (out of the major components of the Earth's crust). The oxidation of calcium, aluminium, silicon, etc, occurred much before that. It occurred when the Earth was forming, and possibly even in the solar nebula that existed before Earth even formed. This was 2 billion years before the GOE.&lt;/p&gt;&#xA;&lt;p&gt;Let's put this on a time line:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;~4.5 billion years ago, Earth formed. Calcium, aluminium, silicon were all oxidised. Only some of the iron was oxidised.&lt;/li&gt;&#xA;&lt;li&gt;~2.5 billion years ago. Photosynthesis causes oxygen to rise, but the rise is limited because of the presence of iron in the crust. Any oxygen that is produced, is consumed by the oxidation of iron. Eventually all iron is oxidised and oxygen contents can freely rise.&lt;/li&gt;&#xA;&lt;li&gt;~0.5 billion years ago. The section you refer to is deposited.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-07-30T02:33:07.153" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8493" PostTypeId="1" CreationDate="2016-07-31T03:51:06.023" Score="3" ViewCount="191" Body="&lt;p&gt;Volcanic tuff was a key material in the Roman invention of concrete, something that modern concrete, or &quot;Portland cement&quot;, lacked.  With tuff, not only would Roman concrete be waterproof, it would also harden as it would get older.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the concerns of both geologists and construction designers, how common is volcanic tuff?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FQN6I.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FQN6I.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an example for what I'm looking for, this map shows grey veins of coal.  Is there a similar map showing global distribution of volcanic tuff deposits?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastActivityDate="2016-07-31T03:51:06.023" Title="How Common is Volcanic Tuff?" Tags="|rocks|mining|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8496" PostTypeId="1" AcceptedAnswerId="16388" CreationDate="2016-08-01T07:07:01.737" Score="7" ViewCount="224" Body="&lt;p&gt;We saw recently the &lt;a href=&quot;https://en.wikipedia.org/wiki/Air_travel_disruption_after_the_2010_Eyjafjallaj%C3%B6kull_eruption&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iceland volcano Eyjafjallajökull produced&lt;/a&gt; significant gaseous output that impacted the flight paths of several planes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When we look at &lt;a href=&quot;https://en.wikipedia.org/wiki/Volcanic_gas#Composition&quot; rel=&quot;nofollow noreferrer&quot;&gt;volcanic gas components&lt;/a&gt;, we &lt;a href=&quot;http://study.com/academy/lesson/volcanic-eruption-gases-released-their-effects.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;see they produce&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;water vapor (H&lt;sub&gt;2&lt;/sub&gt;O)&lt;/li&gt;&#xA;&lt;li&gt;carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;)&lt;/li&gt;&#xA;&lt;li&gt;sulfur either as sulfur dioxide (SO&lt;sub&gt;2&lt;/sub&gt;) (high-temperature volcanic gases) or hydrogen sulfide (H&lt;sub&gt;2&lt;/sub&gt;S)&lt;/li&gt;&#xA;&lt;li&gt;nitrogen&lt;/li&gt;&#xA;&lt;li&gt;argon&lt;/li&gt;&#xA;&lt;li&gt;helium&lt;/li&gt;&#xA;&lt;li&gt;neon&lt;/li&gt;&#xA;&lt;li&gt;methane&lt;/li&gt;&#xA;&lt;li&gt;carbon monoxide&lt;/li&gt;&#xA;&lt;li&gt;hydrogen &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I'm trying to answer the question - &quot;how many 'standard volcanic eruptions' does it take to product X moles of sulfur dioxide.&quot; Can I do it in terms of Y number of &lt;a href=&quot;https://en.wikipedia.org/wiki/1980_eruption_of_Mount_St._Helens&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mount St. Helens 1980 eruptions&lt;/a&gt;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: &lt;strong&gt;Is there a 'standard size' volcanic eruption in terms of gas output?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="895" LastEditorUserId="11908" LastEditDate="2019-03-03T17:41:05.587" LastActivityDate="2019-03-03T20:20:58.650" Title="Is there a 'standard size' for volcanic eruptions in terms of gas output?" Tags="|atmosphere|volcanology|volcanic-hazard|gas|volcanic-eruption|" AnswerCount="1" CommentCount="4" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="8497" PostTypeId="1" CreationDate="2016-08-01T13:08:23.413" Score="2" ViewCount="349" Body="&lt;p&gt;The official story says like Cambrian Ordovician transition was caused/accompanied by animals learned how to build the Ca-based skeletons. These skeletons and shells started to fall upon the sea bed causing the rich and durable limestone formations on top of earth crust. I wonder didn't limestone form itself in pre-Cambrian epochs? You already had the CaO in the primordial crust (&lt;a href=&quot;https://earthscience.stackexchange.com/a/8490/6272&quot;&gt;I wonder why do you give the leverage to he people who chronically cannot understand a question even after it was answered&lt;/a&gt;). You do not need animals for the CaO to react with CO&lt;sub&gt;2&lt;/sub&gt;. Actually, there was much more CO&lt;sub&gt;2&lt;/sub&gt; even before Cambrian, billions of years ago. But we do not see any limestone formations at that time. So, why do we see the limestone on the top layer sediments 460-60 mln years ago rather than at the very bottom of the crust?&lt;/p&gt;&#xA;" OwnerUserId="6272" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-08-06T22:14:18.520" Title="Why do we see the limestone on top of Cambrian layer?" Tags="|earth-history|limestone|crust|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="8498" PostTypeId="1" CreationDate="2016-08-01T13:36:32.190" Score="2" ViewCount="129" Body="&lt;p&gt;I understand this might be drifting into the black hole of subjectivity but I would like to know if anyone knows if there is a generally accepted practice. If one has a detrital zircon with a core age of 1100 Ma and a rim age of 400 Ma and one wanted to construct one of the many graphs for visualizing such data (e.g. KDE, PDP, histogram plots), would one report both ages or only one? If only one age is to be reported, then does one choose the core or the rim? If you choose the core, then perhaps it reveals something about the ultimate source of the zircon. But the rim would most likely represent the source from which the sediment was derived (this being the goal of a provenance study!). However, if you have other detrital zircons in your sample that yield an age of 1100 Ma then perhaps one can include both the core and rim ages?&lt;/p&gt;&#xA;" OwnerUserId="6083" LastActivityDate="2016-08-01T13:36:32.190" Title="How should core-rim detrital zircon ages be reported in a sedimentary provenance study?" Tags="|geology|sedimentology|geochronology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8499" PostTypeId="1" CreationDate="2016-08-01T16:53:31.643" Score="6" ViewCount="776" Body="&lt;p&gt;&lt;a href=&quot;http://www.gi.ee/geoturism/BKlint_ENG_062011_100dpiS.pdf&quot; rel=&quot;noreferrer&quot;&gt;There is information&lt;/a&gt; which says that East European Platform sticks out at the Baltic Sea and, therefore, we can see the ordovican layer in Estonia whereas &lt;code&gt;crystalline Paleoproterosoic basement&lt;/code&gt; crops up in the Finland. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iEvZg.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iEvZg.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What does that mean? I see that other layers are cambrian and ordovican, which means that they were formed 500 and 400 mln years ago. Does it mean that East European Platform has formed 2 giga years ago when we had the Paleoproterozoic era? I ask because it is hard to believe that we could have the magma cristallization at that scale to solidify over the whole continents. I expect that these processes that shield formation has finihsed in the range 5-4 giga years ago and pretty solidified Earth existed for ~ca 2 bln years before Paloproterozoic ever begun. Why is that platform called Paleoproterozoic?&lt;/p&gt;&#xA;" OwnerUserId="6272" LastActivityDate="2016-08-02T07:53:31.713" Title="The age of tectonic plates" Tags="|earth-history|crust|lithosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8500" PostTypeId="2" ParentId="8499" CreationDate="2016-08-02T07:47:52.450" Score="2" Body="&lt;p&gt;The process of forming continental crust is indeed thought to have started in the early Archean (i. e. between ca. 4 Ga and ca. 3.5 Ga). But it did continue later: Hawkesworth &amp;amp; Kemp showed in their 2006 review that while much of the continental crust had formed by 2 Ga, i. e. until the middle of the Paleoproterozoic, some of it still continued forming later.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as the Fennoscandian shield is concerned, it seems that though it started forming in the Meso-Archean, and that much of the eastern and northern part of it are Archean (see Slabunov et al. 2006), the southern and western part is indeed mostly Paleo- and Mesoproterozoic (see e. g. Lahtinen et al. 2008). In Figure 1 of Lahtinen et al. 2008, it seems that the southern part of Finland, just north of the Gulf of Finland (the Uusimaa Belt) is Paleoproterozoic. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Sources:&lt;br&gt;&#xA;Hawkesworth &amp;amp; Kemp, 2006. &lt;a href=&quot;http://dx.doi.org/10.1038/nature05191&quot; rel=&quot;nofollow&quot;&gt;Evolution of the continental crust&lt;/a&gt;. &lt;em&gt;Nature&lt;/em&gt;, 443: 811-817.&lt;br&gt;&#xA;Lahtinen et al., 2008. &lt;a href=&quot;http://www.episodes.org/index.php/epi/article/view/64227&quot; rel=&quot;nofollow&quot;&gt;Paleoproterozoic evolution of Fennoscandia and&#xA;Greenland&lt;/a&gt;.&lt;em&gt;Episodes&lt;/em&gt;, 31: 20-28.&#xA;Slabunov et al., 2006. &lt;a href=&quot;https://www.researchgate.net/profile/Sergei_Svetov/publication/252137493_The_Archaean_nucleus_of_the_Fennoscandian_Baltic_Shield/links/53d0a3a30cf2fd75bc5d36d7.pdf&quot; rel=&quot;nofollow&quot;&gt;The Archaean nucleus of the Fennoscandian (Baltic) Shield&lt;/a&gt;. In Gee &amp;amp; Stephenson (eds): &lt;em&gt;European Lithosphere Dynamics&lt;/em&gt;, Geological Society of London, Memoirs, 32: 627-644.&#xA;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2016-08-02T07:53:31.713" LastActivityDate="2016-08-02T07:53:31.713" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8502" PostTypeId="1" AcceptedAnswerId="8504" CreationDate="2016-08-02T13:22:08.437" Score="5" ViewCount="778" Body="&lt;p&gt;I'm developing a semi-realistic game involving stereotypical dwarves digging into mountainsides and carving out grand caverns for themselves, similar to those in Moria or the Lonely Mountain from Tolkien's works.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm attempting to research what kind of layers of rock (in layman's terms) you'd expect to find in a typical non-volcanic mountain range in say, northern Europe. So far though I'm at a loss so at this point anything would be a help!&lt;/p&gt;&#xA;" OwnerUserId="6400" LastActivityDate="2016-08-02T17:05:06.407" Title="If I was to tunnel straight through a mountain, what kind of rock would I find?" Tags="|geology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8503" PostTypeId="2" ParentId="8502" CreationDate="2016-08-02T15:44:58.103" Score="3" Body="&lt;p&gt;It would completely depend on location. For instance, Sawtooth mountains in Idaho is a very large granite batholith so the rock in the tunnel would igneous granitic rock with varying textures and crystal sizes.  You need to define a geological setting for the location first.&lt;br&gt;&#xA; - Pacific Northwest - volcanic rock, large volcanic peaks.&#xA; - BlackHills of SD - Granitic core surrounded by metamorphic sedimentary rocks  and unlatered sedimentary rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My recommendation is check out a couple of the Roadside Geology of .... books. These books are written in layman terms with explanations of the geology.&lt;br&gt;&#xA;See Roadside geology of Colorado ISBN:087842105X&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2016-08-02T15:44:58.103" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8504" PostTypeId="2" ParentId="8502" CreationDate="2016-08-02T16:54:38.340" Score="6" Body="&lt;p&gt;As Gary mentioned, it really depends on particular context for your mountain. How did it form? Is it volcanic in nature? Or maybe just old rocks being uplifted by some episode of compression.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On average, Earth's crust is pretty much granite. So chances are that you will find that inside your mountain. That wouldn't be a bad assumption. Granites form by cooling magma slowly, so most volcanic-type mountains are made of granite or something similar. For example, the Andes (below) are made of fine-grained Andesite near the surface and Diorite (Andesite's coarse-grained version, which is similar to Granite, but not quite) at depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IsSoy.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IsSoy.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case of cooling magma to form rocks, the slower the cooling, the larger the crystals will be. So rocks that cooled near the surface, will be composed of tiny crystals while rocks that cooled deeper will have larger crystals. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hvoe6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hvoe6.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could argue for more exotic rock types but that would imply a slightly more complex geological history (which is totally possible). For example, you could have uplifted a huge package of sedimentary rocks without any volcanism involved. Or you could have simply eroded everything around leaving large rock packages like the Venezuelan Tepuis (below).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8ZTNq.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8ZTNq.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, the rocks deep inside a mountain (or simply super old rocks) have also undergone a lot of compression, so sedimentary rocks will be unlikely as you would have converted them into metamorphic rocks, e.g. limestones would be marble, sandstones would be quartzites (like the Tepuis), shales would be slates (or schists, etc.), etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly, metamorphic rocks that have undergone a higher degree of compressional and thermal stress (i.e. deeper in the mountain) will grow larger crystals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/i72Yo.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/i72Yo.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, like anything in geology, other complex scenarios do exist where these rules of thumb don't work. But in general, this should get you started.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyway, hope that helps.&lt;/p&gt;&#xA;" OwnerUserId="4636" LastEditorUserId="4636" LastEditDate="2016-08-02T17:05:06.407" LastActivityDate="2016-08-02T17:05:06.407" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8506" PostTypeId="1" AcceptedAnswerId="8507" CreationDate="2016-08-03T03:10:38.453" Score="4" ViewCount="144" Body="&lt;p&gt;As I know, El Niño and La Niña usually occurs alternatively, but is it possible that El Niño occurs again after El Niño and return to normal state?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="111" LastEditDate="2016-08-03T15:47:02.523" LastActivityDate="2016-08-03T15:47:02.523" Title="Can El Niño/La Niña occur again after normal state?" Tags="|enso|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8507" PostTypeId="2" ParentId="8506" CreationDate="2016-08-03T03:26:54.483" Score="5" Body="&lt;p&gt;If you look at the ENSO index record, you can see many instances of El Niño or La Niña occurring multiple times in a row. For instance, the period 1977-1983 and even after that is a succession of El Niño events with normal conditions in between and no La Niña period.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Wh5Y9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Wh5Y9.png&quot; alt=&quot;NOAA ENSO index&quot;&gt;&lt;/a&gt;&#xA;Multivariate ENSO Index (MEI) from NOAA&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2016-08-03T03:26:54.483" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8508" PostTypeId="1" AcceptedAnswerId="8509" CreationDate="2016-08-04T07:10:53.993" Score="8" ViewCount="1249" Body="&lt;p&gt;I found this &lt;a href=&quot;http://volkov.oce.orst.edu/tides/global.html&quot; rel=&quot;noreferrer&quot;&gt;animation&lt;/a&gt; from a satellite:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/N3FBf.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/N3FBf.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;which shows the motion and elevation of tides on a certain date. Can you find an animation of a date  when there is a &lt;em&gt;spring&lt;/em&gt; tide?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;my question is as follows:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;since the earth moves toward the East, tides should move to the West, but there is only one, at the Antarctica, which goes in that direction and keeps pace with moon, although it never overtakes it, as it was supposed by the theory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What people at Astronomy could not explain is why most tides move to the (North-) West, and that means they run faster than the earth's rotation. Can you explain that? Higher water is at a greater radius from the center of the Earth and must slow down because of conservation of AM,  how can they move faster?&lt;/p&gt;&#xA;" OwnerDisplayName="user6402" LastEditorDisplayName="user6402" LastEditDate="2016-08-05T14:12:32.513" LastActivityDate="2018-05-03T08:13:01.157" Title="The motion of tides" Tags="|ocean|oceanography|tides|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="8509" PostTypeId="2" ParentId="8508" CreationDate="2016-08-04T15:20:26.827" Score="10" Body="&lt;p&gt;This question is quite interesting because it highlights some of the common misconceptions about tides. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://volkov.oce.orst.edu/tides/&quot; rel=&quot;noreferrer&quot;&gt;animation&lt;/a&gt; from &lt;a href=&quot;http://dx.doi.org/10.1175/1520-0426(2002)019%3C0183:EIMOBO%3E2.0.CO;2&quot; rel=&quot;noreferrer&quot;&gt;OSU&lt;/a&gt; shows their model results (not from a satellite as you mentioned, but from a model that assimilates satellite data) for the global tides for a day in 2010 a week removed from the full moon. The &lt;a href=&quot;http://volkov.oce.orst.edu/tides/&quot; rel=&quot;noreferrer&quot;&gt;page&lt;/a&gt; can be easily access on &lt;a href=&quot;http://www.space.com/16830-full-moon-calendar.html&quot; rel=&quot;noreferrer&quot;&gt;the day of a full moon&lt;/a&gt; and it will provide you with a comparison from the animation posted with the question. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The two tidal bulges are a simple representation of the effects of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Tidal_force&quot; rel=&quot;noreferrer&quot;&gt;tide generating forces&lt;/a&gt; of the Moon on Earth. &lt;a href=&quot;https://i.stack.imgur.com/cSsLn.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cSsLn.png&quot; alt=&quot;tide generating force&quot;&gt;&lt;/a&gt;(&lt;a href=&quot;https://en.wikipedia.org/wiki/File:Field_tidal.svg&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/File:Field_tidal.svg&lt;/a&gt;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The resulting explanation of the tides is the &lt;a href=&quot;http://www.vims.edu/research/units/labgroups/tc_tutorial/static.php&quot; rel=&quot;noreferrer&quot;&gt;Equilibrium Theory of the Tides&lt;/a&gt; that was first introduced by Newton in the &lt;em&gt;Principia&lt;/em&gt; and provided the correct explanation for the tidal force but under the assumption that the planet was covered by a uniform ocean. The equilibrium theory considered the gravitational forces from the Sun and Moon but ignored important effects such as the rotation of Earth and the effects of continents, and could not explain the real ocean tides.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Pierre-Simon_Laplace&quot; rel=&quot;noreferrer&quot;&gt;Laplace&lt;/a&gt; proposed the Dynamic Theory of the Tides that also considered resonance effects, friction, and the natural periods of the ocean basins on Earth. Laplace's theory was able to predict the tides with relative accuracy and also predicted the occurrence of &lt;a href=&quot;https://en.wikipedia.org/wiki/Amphidromic_point&quot; rel=&quot;noreferrer&quot;&gt;amphidromic points&lt;/a&gt;, where the tide was zero for an specific constituents. The presence of amphidromic points can be easily visualized in the animation provided. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MGQIy.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MGQIy.jpg&quot; alt=&quot;Wikipedia amphidromic points&quot;&gt;&lt;/a&gt;(&lt;a href=&quot;https://en.wikipedia.org/wiki/File:M2_tidal_constituent.jpg&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/File:M2_tidal_constituent.jpg&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main constituent of the tide ($M_2$) goes around these amphidromic points and is the main effect that can be observed in the animation. The tides therefore do not move from east to west or the other way around but rather propagate around these amphidromic points. The real tides are thus more complex than the simplify ocean bulge diagram as they are affected by the presence of the continents. The ocean bulges reflect on the shorelines creating resonant motions and standing waves. Standing waves have regions of high amplitude variation (antinodes) and regions of zero amplitude variation (nodes). So, it's not surprising that we see places where the tides are nearly zero in the ocean. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, coastal topography can intensify the tidal height fluctuations. In fact, these effects are usually greater than the tidal bulges would be in a stationary Earth-Moon system. While the height of the tide in the equilibrium tidal theory is less than half a meter, the inclusion of the continents and coastal topography results in tides up to 17 meters in some regions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Going back to &quot;fact&quot; that the &quot;there is not a single moment of the day when there is an elevation ahead of the moon&quot;, the difference between the passing of the Moon and the bulges due to frictional effects on Earth is minimal. In fact, the angle is only 3&amp;deg;, so the tides are late by about 12 minutes, which clearly is not something you can visualize in the animation or in the image provided.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2016-08-04T15:20:26.827" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="8510" PostTypeId="1" CreationDate="2016-08-04T23:34:53.780" Score="2" ViewCount="66" Body="&lt;p&gt;My question is related to a former question about the Earth's early crust.&#xA;I would like to understand HOW the crust that seems to have been mafic during the Hadean, changed into the other more felsic compositions later. Why this happened? How did it arrive to being so well-separated with the felsic crust under the oceans (I understand that felsic is buoyant and it does not get dense enough, so it can't be under the oceans) But HOW? and WHY?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;" OwnerUserId="6414" LastEditorUserId="725" LastEditDate="2016-08-05T00:26:45.487" LastActivityDate="2016-08-05T00:26:45.487" Title="Early Earth crust" Tags="|geology|crust|" AnswerCount="0" CommentCount="1" ClosedDate="2016-08-08T08:14:51.747" ContentLicense="CC BY-SA 3.0" />
  <row Id="8511" PostTypeId="1" AcceptedAnswerId="8513" CreationDate="2016-08-05T00:35:49.833" Score="4" ViewCount="3000" Body="&lt;p&gt;So, I'm trying to find the Height of the Top of a cloud from basic weather information (ie. temperature on the ground, altitude, pressure, humidity, dew point, etc.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm looking for an equation that will give or at least estimate the cloud top. Doing some searching, I've found this equation:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Cloud top height can be calculated by the formula&lt;br&gt;&#xA;           h [km] = -8 * LOGS (cloud_top_press [hPa]/1013).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.brockmann-consult.de/CloudStructures/introduction.htm&quot; rel=&quot;nofollow&quot;&gt;From this site&lt;/a&gt;. My question is, will this equation produce the height of a cloud and what does &quot;LOGS&quot; mean in this equation?&lt;/p&gt;&#xA;" OwnerUserId="5602" LastActivityDate="2016-08-05T17:29:41.393" Title="Calculate the Top of a Cloud" Tags="|meteorology|clouds|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8512" PostTypeId="1" CreationDate="2016-08-05T14:35:33.413" Score="1" ViewCount="345" Body="&lt;p&gt;I read &lt;a href=&quot;http://www.jeanlouisetienne.com/en/images/encyclo/imprimer/11.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.jeanlouisetienne.com/en/images/encyclo/imprimer/11.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;that in the arctic, (and no doubt the antarctic - the pole regions), &quot;Spring and autumn last just a few weeks each&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand that in the summer the earth is tilted such that the hemisphere where it is summer is tilted towards the sun so is at less of an angle from the sun. So hence in summer it's warmer and days are longer.  I understand that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I don't understand why spring and autumn should be shorter for countries near the poles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand this diagram for seasons (and I understand that astronomical seasons are similar to meteriological seasons)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But that diagram doesn't even show a short autumn and spring at the poles (let alone indicate why)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IoCuN.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IoCuN.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have heard that with rainforests they define seasons by rainfall, rather than earth's position in relation to the sun.  I don't know if poles are anything like that in that they somehow define seasons differently?  &lt;/p&gt;&#xA;" OwnerUserId="5960" LastActivityDate="2016-08-05T14:35:33.413" Title="Why would the arctic have very short spring and autumn?" Tags="|seasons|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8513" PostTypeId="2" ParentId="8511" CreationDate="2016-08-05T14:55:24.070" Score="6" Body="&lt;p&gt;The formula you found comes from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Barometric_formula&quot; rel=&quot;nofollow&quot;&gt;barometric formula&lt;/a&gt;. It assumes a hydrostatic atmosphere (no vertical accelerations), a constant temperature with height (or a mean temperature) and uses the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ideal_gas_law&quot; rel=&quot;nofollow&quot;&gt;ideal gas law&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$h= -\frac{RT}{g} \cdot \log \frac{p}{p_{sfc}}&#xA;$$&#xA;where h is height above ground, R is the ideal gas constant, T is the mean temperature, g is the gravitational constant, p is the pressure of the cloud top in your case and $p_{sfc}$ is &lt;a href=&quot;https://en.wikipedia.org/wiki/Surface_pressure&quot; rel=&quot;nofollow&quot;&gt;surface pressure&lt;/a&gt; (not reduced)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first factor comes down to a value of $-8$km if $T \approx 273$ K. This value is also known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Scale_height&quot; rel=&quot;nofollow&quot;&gt;scale height&lt;/a&gt;. $p_{sfc}$ is approx. 1013 hPa if you're at sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So LOGS would most probably mean the natural logarithm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't think there is a simple equation for the cloud top height from ground observations because e.g. how high a cumulus grows depends on the temperature of the surrounding air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cloud base height and cloud top height are two totally different things. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Lifted_condensation_level&quot; rel=&quot;nofollow&quot;&gt;cloud base height formula&lt;/a&gt; does not depend on the on the upper air temperature. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whether a thermal (which evolves into the cloud later on) reaches its cloud base or not, is not sure. As long as it's warmer than its surroundings, it rises. The same for the cloud: It rises up as long as it is warmer than its surroundings. You may know what's the temperature of the cloud at each height, but how cold the air at, say 15,000 ft is, varies a lot.&lt;/p&gt;&#xA;" OwnerUserId="3419" LastEditorUserId="3419" LastEditDate="2016-08-05T17:29:41.393" LastActivityDate="2016-08-05T17:29:41.393" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8515" PostTypeId="1" AcceptedAnswerId="12821" CreationDate="2016-08-05T16:20:25.803" Score="3" ViewCount="932" Body="&lt;p&gt;According to &lt;a href=&quot;https://www.youtube.com/watch?v=nH3bmG-KjvU&quot; rel=&quot;nofollow&quot;&gt;https://www.youtube.com/watch?v=nH3bmG-KjvU&lt;/a&gt;, Earth would have stable weather patterns after it stopped spinning and according to &lt;a href=&quot;https://www.youtube.com/watch?v=QHwLopLUrB8&quot; rel=&quot;nofollow&quot;&gt;https://www.youtube.com/watch?v=QHwLopLUrB8&lt;/a&gt;, Earth would have vigorous winds if it had an 8 hour rotation period. Would the Coriolis force responsible for vigorous winds?&lt;/p&gt;&#xA;" OwnerUserId="4846" LastEditorUserId="4846" LastEditDate="2016-08-05T16:33:41.507" LastActivityDate="2018-02-02T16:59:45.067" Title="Why would Earth have stable weather patterns if it stopped spinning and vigorous weather if it had a much faster rotation?" Tags="|climate|wind|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8516" PostTypeId="1" CreationDate="2016-08-05T17:15:49.113" Score="4" ViewCount="228" Body="&lt;p&gt;I think that when the air heats up in the day, the radiation from the ground contributes way more to its heating at altitudes more than 300 meters above the ground than convection currents of air heat from the ground. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also think radiative cooling of the air directly contributes way more to the cooling of air more than 300 meters above the ground than conduction from the ground. I don't see how the air at that height could be so fast to warm up and cool just by conduction from the ground. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If these assumptions are true, does the carbon dioxide we released into the air speed up the absorption of radiation from the ground by the air in the day and the radiative cooling of the air at night because Carbon dioxide absorbs infrared light better than air?&lt;/p&gt;&#xA;" OwnerUserId="4846" LastEditorUserId="6703" LastEditDate="2016-10-24T18:03:24.117" LastActivityDate="2016-10-24T18:03:24.117" Title="Are we changing Earth's weather with global warming?" Tags="|climate-change|weather-forecasting|atmospheric-radiation|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8517" PostTypeId="2" ParentId="8497" CreationDate="2016-08-05T18:44:36.673" Score="1" Body="&lt;p&gt;No.  CaO will not exist in most environments for any significant time in the presence of CO2, it will react to form CaCO3.  I doubt CaO is the primary source of Ca in our world.  Silicates are likely the original source of Ca in our oceans &lt;a href=&quot;https://en.wikipedia.org/wiki/Silicate_minerals&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Silicate_minerals&lt;/a&gt;.  CaCO3 will partially dissolve or corrode in water to form an aqueous solution of Ca +2 + 2 HCO3 -.  The dissolution of the CaCO3 in water is an equilibrium reaction based on the acidity and temperature of the water, this is why the acidification of the oceans is a concern for our marine life.  I am not a chemist or a biologist but organisms will extract the aqueous Ca +2 ions found in the water to form shells etc.  Because these organisms are not evenly distributed in the ocean their shells and skeletons will and have accumulated the CaCO3 in distinct areas.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2016-08-05T18:44:36.673" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8518" PostTypeId="1" AcceptedAnswerId="8524" CreationDate="2016-08-05T21:03:06.320" Score="10" ViewCount="6432" Body="&lt;p&gt;If you look at &lt;a href=&quot;https://iridl.ldeo.columbia.edu/maproom/Global/Climatologies/Vector_Winds.html?bbox=bb%3A12.009%3A18.793%3A39.800%3A42.107%3Abb&amp;amp;T=Jul&quot; rel=&quot;noreferrer&quot;&gt;this wind map&lt;/a&gt; (for July, but following the link you can also view other months):&#xA;&lt;img src=&quot;https://i.stack.imgur.com/2KXEX.png&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;you will see that Egypt gets its air from the Mediterranean sea. During other months it could get less moist air, but still from the same direction.&lt;br /&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you look at the topography of Egypt:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/1qBuE.png&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(taken from &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Egypt_Topography.png&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;), you will see that it doesn't have any mountain ranges that could intercept the precipitation. But it still receives very little rain.&lt;br /&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't quite understand why. Is the Mediterranean air not moist enough?&lt;/p&gt;&#xA;" OwnerUserId="6416" LastEditorUserId="6416" LastEditDate="2016-08-06T20:51:10.137" LastActivityDate="2021-05-24T08:09:14.027" Title="Why is Egypt so dry?" Tags="|precipitation|atmospheric-circulation|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8519" PostTypeId="1" CreationDate="2016-08-05T22:01:02.030" Score="-1" ViewCount="132" Body="&lt;p&gt;For my fictitious alternate Earth, one of the most important things to consider is that any change in geography and geology can result in profound changes in environment and climate. I've been searching Google for any climate forums that don't focus on our current climate change crisis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do you know any climate-based forums on-line that don't focus on our current climate change crisis and allow hard science on fictional climatic patterns?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastEditorUserId="595" LastEditDate="2016-08-07T12:40:44.830" LastActivityDate="2016-08-11T03:48:06.870" Title="The Search for Climate Forums" Tags="|climate|climate-models|world-building|" AnswerCount="1" CommentCount="1" ClosedDate="2016-08-15T04:15:12.127" ContentLicense="CC BY-SA 3.0" />
  <row Id="8521" PostTypeId="1" AcceptedAnswerId="8526" CreationDate="2016-08-06T12:55:17.027" Score="2" ViewCount="2556" Body="&lt;p&gt;I knew so far that, the classification of crust as SiAl-SiMa, vs. classification of crust as Continental-Oceanic; are completely different, as told in my school geography and university paleobiology class. (However I'm not a geology student)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Like, &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LPbnV.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LPbnV.png&quot; alt=&quot;the 2 concept&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where Continental crust and oceanic crust placed side-by-side, so, no-part of continental crust can cover-up oceanic crust. Also, in the places of continental crust; both SiAl and SiMa could be found&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now a geology student is telling me, that is wrong. SiAl is Same as Continental crust, and SiMa is same as Oceanic crust. He's Also telling, &quot;SiAl or Continental crust lie upon Sima or Oceanic crust&quot;. That implies at the same-place on Earth, continental and oceanic crust occur together, one upon other.&lt;/p&gt;&#xA;" OwnerDisplayName="user6419" LastEditorUserId="725" LastEditDate="2016-08-06T22:25:20.157" LastActivityDate="2016-08-07T10:08:02.183" Title="Which one is the correct concept of Continental Crust and Oceanic Crust?" Tags="|mantle|crust|lithosphere|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8522" PostTypeId="2" ParentId="8518" CreationDate="2016-08-06T15:00:51.003" Score="9" Body="&lt;p&gt;If you take a look at the atmospheric circulation pattern, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hadley_cell&quot;&gt;Hadley Cell&lt;/a&gt;s in particular, they tell the story. The northern edge of Africa is on the descending edge of a Hadley Cell, which means&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Having &lt;em&gt;lost most of its water vapor&lt;/em&gt; to condensation and precipitation&#xA;  in the upward branch of the Hadley cell circulation, the &lt;em&gt;descending&#xA;  air is dry&lt;/em&gt;. As the air descends, low relative humidities are produced&#xA;  as the air is warmed adiabatically by compression from the overlying&#xA;  air, producing &lt;em&gt;a region of higher pressure&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The main air mass being dry already, and the High pressure system generated by the descending air mass along the 30 degree lines work to make the physics required for &lt;a href=&quot;https://en.wikipedia.org/wiki/Precipitation&quot;&gt;precipitation&lt;/a&gt; just not want to happen in these regions. You have to get a combination of enough humidity to reach saturation, and then cool the air to reach its dew point.  The desert region formed by the lack of atmospheric moisture(remember Hadley cell) can't add any humidity of its own through evaporation or transpiration, so the global patterns dominate, even being right on the oceans edge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that Hadley cell edges at the 30 degree &lt;em&gt;south&lt;/em&gt; also cut through the &lt;a href=&quot;https://en.wikipedia.org/wiki/Namib_Desert&quot;&gt;Namib&lt;/a&gt;,&lt;a href=&quot;https://en.wikipedia.org/wiki/Kalahari_Desert&quot;&gt;Kalahari&lt;/a&gt;, and in South America the &lt;a href=&quot;https://en.wikipedia.org/wiki/Atacama_Desert&quot;&gt;Atacama&lt;/a&gt; deserts, with their own ocean exposure.&lt;/p&gt;&#xA;" OwnerUserId="6057" LastActivityDate="2016-08-06T15:00:51.003" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8523" PostTypeId="1" AcceptedAnswerId="8527" CreationDate="2016-08-06T15:11:21.917" Score="2" ViewCount="4352" Body="&lt;p&gt;Is it due to the longitudinal nature of the seismic waves?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When a heavy bus or truck goes by at high-speed, the shaking in nearby ground is &lt;strong&gt;not&lt;/strong&gt; mistaken as dizziness, rather the feet and body feel a vertical jerk (seemingly a transverse wave vertical to the ground).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But when a natural, mild earthquake takes place, it is not felt as a jerk or switch in a direction at all. Rather we feel it for a while as dizziness. I have experienced this, and heard of many others who have as well.  In-fact &lt;strong&gt;it takes a few seconds to distinguish whether it is dizziness or an earthquake.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it due to the longitudinal waves? Is it because they are horizontal with the ground, matching the direction of dizziness?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also I guess maybe there may be similarity between the &lt;strong&gt;frequency&lt;/strong&gt; of seismic waves and &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Optokinetic_nystagmus.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;this video&lt;/a&gt; from &lt;a href=&quot;https://en.wikipedia.org/wiki/Vertigo&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia's article on vertigo&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NQ85w.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NQ85w.gif&quot; alt=&quot;vertigo eye movement from Wikipedia&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does this phenomenon's frequency act similarly to the motion and simulates  dizziness?&lt;/p&gt;&#xA;" OwnerDisplayName="user6419" LastEditorUserId="6298" LastEditDate="2018-04-02T10:26:32.587" LastActivityDate="2020-07-23T18:08:28.163" Title="Why is a mild earthquake often mistaken as dizziness or vertigo?" Tags="|earthquakes|waves|seismic|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8524" PostTypeId="2" ParentId="8518" CreationDate="2016-08-06T17:20:08.710" Score="-1" Body="&lt;p&gt;I suppose that the water gets lost to some underground aquifer. And then evaporates during the dry months.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.mwri.gov.eg/PDF_files/Ground_Water.pdf&quot; rel=&quot;nofollow&quot;&gt;http://www.mwri.gov.eg/PDF_files/Ground_Water.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Otherwise it wouldn't be possible to explain why the water that rains down in the Qattara stripe doesn't evaporate straight away to cause rains further south, and so on all the way towards Sudan. It obviously can't drain towards the Nile, because the Nile basin in Egypt is very narrow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://pp.vk.me/c636017/v636017254/210c8/cKUE9yHehzI.jpg&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Combined graphics; basin outline: Nile Basin Initiative, precipitation map: Ministry of water resources and irrigation).&lt;/p&gt;&#xA;" OwnerUserId="6416" LastEditorUserId="6416" LastEditDate="2016-08-09T14:24:41.460" LastActivityDate="2016-08-09T14:24:41.460" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8525" PostTypeId="1" AcceptedAnswerId="8528" CreationDate="2016-08-06T20:26:50.027" Score="3" ViewCount="481" Body="&lt;p&gt;Much ado has been made by a few petroleum engineers and global-warming alarmist about all of the methane gas trapped in frozen form, mostly on the ocean floors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &quot;What-if&quot; scenario begins to play out in 2080 or so, when a few petroleum engineers claim that the skies will start to turn a brownish color, making the earth even hotter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These comments are buried deep in old magazine articles and by now these engineers are probably working for another employer. Even Al Gore did not say much at all about natural frozen methane gas being set free in massive quantities. But a few geologist and alarmist say it will happen as expected.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even if it comes true, questions abound about what year it maybe dense enough to make the Earth like Venus. Will it mean that as it builds up it will move closer to the ground and begin to poison us directly? Birds will drop out of the sky by the millions. Animals will move down from tall mountains. 90% of the human race could die off, but some would die from ignorance, like in hurricane Katrina.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would this be the toxic gas that could &quot;Shroud the world&quot; within the next 100 years? Someone please prove this is wrong, or at least there are &quot;workarounds&quot; for the problem.&lt;/p&gt;&#xA;" OwnerDisplayName="user6420" LastActivityDate="2019-05-21T14:19:20.047" Title="Can runaway methane gas emissions be an extinction level event?" Tags="|greenhouse-gases|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8526" PostTypeId="2" ParentId="8521" CreationDate="2016-08-06T22:32:38.573" Score="2" Body="&lt;p&gt;The SiAl-SiMa classification is very general. The continental crust is much more varied than that, but it is ok for a first approximation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The oceanic crust is dominantly mafic (aka SiMa), composed of basalt and gabbro. The continental crust is much more complex than that. The upper layer of the continental crust is felsic (aka SiAl), mostly of a granite or a granodiorite composition. The lower part of the continental crust is much more mafic (again, aka SiMa) and the composition of that lower layer has similarities to the oceanic crust. However, it is not the same to oceanic crust. Whereas the mafic rocks in the oceanic crust form by partial melting of mantle ultramafic rocks, the mafic rocks of the lower continental crust form by repeated metamorphic processes and extraction events of felsic material. Yes, there are gabbros in there but most of the lower continental crust is composed of high-T restite rich granulites and eclogites, rather than the gabbro you see in the oceanic crust.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a picture to help you visualise it, with slight editing by myself:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hlD1D.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hlD1D.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in short, the lower continental crust is compositionally similar to the oceanic crust, but it has different origins and it is &lt;em&gt;not&lt;/em&gt; an extension of the oceanic crust.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-08-06T22:32:38.573" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8527" PostTypeId="2" ParentId="8523" CreationDate="2016-08-07T08:29:38.127" Score="3" Body="&lt;p&gt;Having experienced many minor earthquakes (Mag 3 to 5 in the East African Rift Valley, Samoa, Solomon Islands, Philippines and Indonesia), and one major life-threatening earthquake (Magnitude 8, Nepal), I can make a few personal observations about physiological reactions.&#xA;First, You are quite correct about the body picking up any swaying feeling, and interpreting this as dizziness. I was in an 11th floor hotel room in Bangkok when an aftershock of the Aceh earthquake occurred. My first thought was &quot;Did I drink too much beer this evening&quot;? I wasn't alone. When I opened the door into the corridor, the occupants of nearly every room were looking out and wondering much the same thing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second, after experiencing a big one the body becomes hypersensitive - conditioned to pick up vibrations that could be the onset of a major quake. Now, at the onset of any vibration, my brain goes straight to &quot;how big is it - should I run to the nearest exit&quot;? This response is now &lt;em&gt;much&lt;/em&gt; faster than the sensation of dizziness. Also I now pick up many vibrations that nobody else around me seems to notice. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thirdly, I am not sure I agree with you about &lt;em&gt;vertical&lt;/em&gt; motion being the trigger. It seems to me that lateral motion - moving one's feet sideways relative to the head, creates a slight imbalance, which the ears interpret as 'dizziness'. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-07T08:29:38.127" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8528" PostTypeId="2" ParentId="8525" CreationDate="2016-08-07T09:47:41.543" Score="3" Body="&lt;p&gt;&lt;em&gt;IF&lt;/em&gt;, and it's a very big &lt;em&gt;IF&lt;/em&gt;, all the methane hydrate were to be released rapidly, then the planetary climate would be stuffed. But it won't happen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How much methane hydrate will be released due to global warming? Run 30 different atmospheric-ocean-coupled global climatic models, and you will get 30 different answers - all of them based upon arguable assumptions. The scaremongering doomsayers love to fanfare the worst case. In which case, &lt;em&gt;some&lt;/em&gt; of your dire forebodings may come about. But first, take a balanced view of the physical reality. The vast majority of all the world's methane hydrate is sufficiently deep, on or in the sea floor, that it will be millennia, if ever, before they melt, thereby contributing to global warming. The deep ocean floor is everywhere only a few degrees above freezing, whereas almost all of the oceanic warming is in the uppermost few hundred metres. Check out the diagram in &lt;a href=&quot;http://worldoceanreview.com/en/wor-1/ocean-chemistry/climate-change-and-methane-hydrates/&quot; rel=&quot;nofollow&quot;&gt;http://worldoceanreview.com/en/wor-1/ocean-chemistry/climate-change-and-methane-hydrates/&lt;/a&gt; and you will see that the pressure-temperature control is such that most of the methane hydrate will always be stable. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The current consensus is that &lt;em&gt;some&lt;/em&gt; methane is already being emitted from the thawing tundra, mainly in Siberia, Canada and Alaska, and some more will be released from shallow seas as and when they warm up. But this won't dominate the global warming process. In fact methane release is just one of at least two dozen feedback processes, some negative but mostly positive, which will influence the rate of global warming for the next few centuries. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Making the world 'toxic', or 'like Venus' or the 'atmosphere turning brown', or 'poisoned birds dropping out of the sky' are all absurd, but that's no reason for complacency. The rise in global atmospheric methane amounts to about 6 parts per billion per year since 2006, or slightly more than 6 ppb in polar regions; significant, but not at all catastrophic. I am far more worried about the accumulating global CO2, which still shows no sign of slowing down despite a dirge of conference resolutions, ineffective carbon taxes, and empty political rhetoric. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for an 'extinction event', the extreme rapidity of global warming, habitat loss, sea level rise, and ocean acidification, all adds up to the fact that we are &lt;em&gt;already&lt;/em&gt; in an extinction event - not for humans, most of whom will be able to engineer their way through a 3 to 4 degree C global temperature rise, but for the rest of the biosphere - with, or without, extra methane. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Notwithstanding the scientific facts, maybe we can all relax, because Donald Trump assures us that climate change is just a fictitious Chinese conspiracy. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-07T09:47:41.543" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8529" PostTypeId="2" ParentId="8521" CreationDate="2016-08-07T10:08:02.183" Score="3" Body="&lt;p&gt;Michael is correct. SIAL and SIMA are very vague and over-simplified summaries of the continental and oceanic crustal compositions. These terms may be OK for school introductions to geology, but you don't have to look far to find many exceptions. There are eroded and fragmented continental remnants, of nominally SIALic composition, in every ocean. Indeed, 100% oceanic crust may include small amounts of highly differentiated plagiogranite (technically SIALic in composition). Then there are bits of oceanic crust, called &lt;em&gt;ophiolites&lt;/em&gt; (SIMA) incorporated into continental crust through processes of obduction and terrain accretion, not to mention the many flood basalt terrains (SIMA), which can occur on either continental or oceanic crust. Whether crust is oceanic or continental is a matter of overall rock density, composition &lt;em&gt;and&lt;/em&gt; crustal thickness. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-07T10:08:02.183" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8530" PostTypeId="2" ParentId="8525" CreationDate="2016-08-07T23:38:57.853" Score="2" Body="&lt;p&gt;2 good answers to this already (one here, one in world building).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To put some very rough estimates to it, CH&lt;sub&gt;4&lt;/sub&gt; or Methane has increased significantly over the last 250 years from about 0.72 parts per billion (ppb) to about 1.83 ppb.  &lt;a href=&quot;http://cdiac.ornl.gov/pns/current_ghg.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;.  This accounts for about 20% of the current man made warming, which might be estimated at 2 degrees C by 2100 (very rough estimate).    If CH&lt;sub&gt;4&lt;/sub&gt; is .4 degrees C of that warming by 2100, that's not nothing, but it's still a significantly smaller problem than CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What's more, CH&lt;sub&gt;4&lt;/sub&gt;'s half life in the atmosphere is shorter than CO&lt;sub&gt;2&lt;/sub&gt;'s, 12.4 years vs over 100 (same source).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If all the Tundra on Earth was to thaw at once (very unlikely), we'd see a big spike in CH&lt;sub&gt;4&lt;/sub&gt; and perhaps an uptick in yearly warming, but within 12 years, half of that extra CH&lt;sub&gt;4&lt;/sub&gt; might be out of the atmosphere.   If the Tundra warms and thaws more gradually, which is more likely, we'd see an increase in CH&lt;sub&gt;4&lt;/sub&gt;, but over time, the increase would level off.  It's not like CO&lt;sub&gt;2&lt;/sub&gt; which continues to build because the earth's systems can't take out out of the atmosphere nearly as fast as we put it in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in and of itself, CH&lt;sub&gt;4&lt;/sub&gt; from melting Tundra isn't a big concern and turning the sky brown or poisoning birds, as others have said, that's very unlikely.   Perhaps it will turn our sunrises and sun sets slightly redder.  (perhaps), I'm not even sure on that point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The CO&lt;sub&gt;2&lt;/sub&gt;, as Gordan points out, is the bigger problem and precisely how world breaking a problem that is, or how soon it is till things get obviously problematic because of CO&lt;sub&gt;2&lt;/sub&gt; remains to be seen.  It's enormously difficult to predict with any accuracy, but it's possible that CO&lt;sub&gt;2&lt;/sub&gt; is a real problem that deserves our concern and effort and I say that without trying to sound like a fear monger.  It's simply the truth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thawing Tundra will give a little push to already existing climate change, that's commonly called a feedback mechanism and such mechanisms are already included in the climate models by the IPCC and others.  The thawing tundra is part of the by 2100 IPPC estimates.   It's not something to worry about on top of what's already being estimated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, on &quot;extinction level events&quot; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Extinction_event&quot; rel=&quot;nofollow noreferrer&quot;&gt;extinction events&lt;/a&gt;.    In a very real sense, the increase in human population and our taking over more and more of the earth is already an extinction event and has been for the last 2 centuries or so.  Extinction events are relatively common, at least, geologically speaking, even the formation and recession of an ice age can cause a significant rise in extinction and what could be called a minor extinction event. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/C4cH6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/C4cH6.png&quot; alt=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/0/06/Extinction_intensity.svg/320px-Extinction_intensity.svg.png&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now if you're talking &lt;a href=&quot;https://en.wikipedia.org/wiki/Extinction_event#Major_extinction_events&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Major&lt;/strong&gt; Extinction Event&lt;/a&gt;, the last once of those was 66 million years ago when that Mt. Everest sized asteroid crashed into the earth and was the primary cause in killing off the dinosaurs.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, part of the answer to your question is a problem of definition.   I think the thawing Tundra, by itself isn't much to worry about, (unless you have a house built on frozen land that turns to slush under your foundation) - and yes, that happens fairly often) . . . but on a planetary scale, The thawing tundra in addition to the CO&lt;sub&gt;2&lt;/sub&gt; and warming planet is maybe 10% or 20% max added to an already existing problem, so the larger worry is the combination, not the Tundra in and of itself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are some methods already in use to help keep Tundra frozen, like &lt;a href=&quot;https://si.wsj.net/public/resources/images/OB-FA306_ev_fro_EV_20091203182244.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;thermosiphons&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.wsj.com/articles/SB10001424052748704576204574531373037560240&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Brown skies and toxic air are statistically quite unlikely and certainly wouldn't be driven just by thawing tundra.  It would take a lot more than just that.   The ocean current stopping might cause such a problem, but trying to work a prediction around that beyond saying it's unlikely, is very difficult, even with everything we've learned so far.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2958" LastEditDate="2019-05-21T14:19:20.047" LastActivityDate="2019-05-21T14:19:20.047" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="8531" PostTypeId="1" CreationDate="2016-08-07T23:59:35.113" Score="8" ViewCount="1925" Body="&lt;p&gt;Elevation is often measured in terms of &quot;[unit of length] above sea level.&quot; Considering that the oceans aren't a uniform height, how is this measured?&lt;/p&gt;&#xA;" OwnerDisplayName="user6422" LastEditorUserId="6428" LastEditDate="2016-08-09T18:40:42.580" LastActivityDate="2016-08-09T18:40:42.580" Title="How to measure elevation above sea level" Tags="|ocean|sea-level|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8532" PostTypeId="1" CreationDate="2016-08-08T11:54:42.453" Score="4" ViewCount="519" Body="&lt;p&gt;I'm trying to compile a list of remote sensing (Earth observing satellite) instruments capable of detecting methane in the atmosphere or near surface of Earth. After some search I have found:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Japanese Greenhouse gases observing satellite (&lt;a href=&quot;http://www.gosat.nies.go.jp/en/&quot; rel=&quot;nofollow&quot;&gt;GOSAT&lt;/a&gt;), launched 2009, measuring CO2 and CH4.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://directory.eoportal.org/web/eoportal/satellite-missions/c-missions/copernicus-sentinel-5&quot; rel=&quot;nofollow&quot;&gt;European Sentinel 5 and Sentinel 5 Precursor&lt;/a&gt;, measuring wide variety of atmospheric contents, 5P to be launched in 2016.&lt;/li&gt;&#xA;&lt;li&gt;Beginning private company &lt;a href=&quot;http://www.ghgsat.com&quot; rel=&quot;nofollow&quot;&gt;GHGSAT&lt;/a&gt;, measuring greenhouse gas (GHG) and air quality gas (AQG) emissions.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Are there any other satellites?&lt;/p&gt;&#xA;" OwnerUserId="3385" LastEditorUserId="595" LastEditDate="2016-09-28T14:31:01.590" LastActivityDate="2024-02-04T07:36:43.190" Title="Methane remote sensing?" Tags="|remote-sensing|methane|greenhouse-gases|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8533" PostTypeId="2" ParentId="8531" CreationDate="2016-08-08T12:42:26.703" Score="3" Body="&lt;p&gt;This question is more about surveying than earth science.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Every country with an ocean coastline determines it's own standard for where sea level is. A mean point between the lowest tide mark and highest tide mark is generally taken to be the average sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A surveying datum station is place at that point and all elevations above sea level, for those countries are referenced back to the national standard datum.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-08-08T12:42:26.703" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8534" PostTypeId="2" ParentId="8531" CreationDate="2016-08-08T14:28:04.943" Score="4" Body="&lt;p&gt;It's actually an inordinately difficult problem. Neither the land nor the sea level is stable. A tide gauge along a coast needs 30 to 40 years of data to filter out the very noisy tidal and other weather signals. By the time one has homed in upon a precise average, one is already within the time-frame of land uplift or subsidence, and that is before we even think about the complexities of climate-change generated sea level rise, or quasi-decadal oceanic oscillations. Then there is the question of Earth's non-homogeneous gravity which affects local sea levels. For example if we correctly measure the elevation of a Himalayan peak relative to average sea level at the Gurarat coast, west India, we get an elevation of 'h1'. We can then measure the same peak relative to sea level in the Ganges delta, east India, which we will call 'h2'. We can make all the usual corrections for Earth's curvature etc., yet h1 will be different to h2 - though both are 'correct'. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is no stable bench mark on 'God's Earth', so maybe the answer is to get off the planet completely. Satellite orbits are not perfect, but they are predictable, so satellite-based measurements of elevation are the best available.   &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-08T14:28:04.943" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8536" PostTypeId="2" ParentId="8375" CreationDate="2016-08-09T02:36:18.223" Score="4" Body="&lt;p&gt;Lenticular clouds don't form because &quot;rising air comes in contact with cooler air&quot; but rather from moist air cooling to its dew point as it is forced to rise over the terrain.  Unlike most clouds that move with the wind, clouds like these are &quot;anchored&quot; to the terrain and the air moves through them.  If you observe them closely you can see new cloud forming as air flows upward and into the cloud on the windward side of the slope and evaporating as it exits descending on the lee side.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As air rises, pressure decreases and the air expands (volume increases).  This results in a temperature decrease in the parcel.  When the rising air cools to its dew point the cloud will form.  In this case air is only rising because it is forced over the mountain.  Once past the peak, the air descends the lee slope and is compressed and warmed.  Once it warms up and relative humidity is below 100% the cloud evaporates.  If the streamlines parallel the contours of the peak, this results in a roughly circular region where the air is suitable for the cloud to form.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the terrain was a long ridge instead of an isolated peak, the lenticular cloud will elongated as a line over the ridge tops.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You generally won't see the cloud elongated downwind, as the air is forced down the lee slope.  What you might instead see are clouds at regular intervals downstream of the mountain if the mountain (and atmospheric stability) has caused a standing wave to form. In this case you might see clouds in the peaks of the wave depending the humidity of the air and the amplitude of the wave.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2016-08-09T02:36:18.223" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8537" PostTypeId="1" AcceptedAnswerId="8560" CreationDate="2016-08-09T06:59:30.657" Score="3" ViewCount="942" Body="&lt;p&gt;According to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/1029/what-is-the-range-of-possible-atmospheric-pressures-on-the-surface-of-the-earth&quot;&gt;this answer&lt;/a&gt; atmospheric pressure can vary between 870 and 1070 mb.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can you tell what (if any) effects would there be on sea level if such difference of pressure (200 mb) on two near areas of the ocean, has anything similar has ever been recorded? If there is an elevation (or depression) can you say to what difference in gravity it corresponds? How do pressure effects compare with Earth's non-homogeneous gravity which affects local sea levels? &lt;/p&gt;&#xA;" OwnerDisplayName="user6402" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-08-12T16:18:29.003" Title="Effects of pressure at sea level" Tags="|ocean|sea-level|barometric-pressure|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8538" PostTypeId="2" ParentId="7668" CreationDate="2016-08-09T09:06:09.763" Score="2" Body="&lt;p&gt;Packages as &lt;a href=&quot;http://www.cwp.mines.edu/cwpcodes/&quot; rel=&quot;nofollow&quot;&gt;Seismic Unix&lt;/a&gt; and &lt;a href=&quot;http://www.ahay.org/wiki/Main_Page&quot; rel=&quot;nofollow&quot;&gt;Madagascar&lt;/a&gt; represent a different philosophy than commercial products. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The packages are open source, so any user can look at the &lt;a href=&quot;https://github.com/JohnWStockwellJr/SeisUnix&quot; rel=&quot;nofollow&quot;&gt;code&lt;/a&gt;, understand how it works (or why it doesn't) and even produce reproducible research so other geophysicists can test the results and use the methods. A great way to learn about seismic processing is indeed by reproduce earlier &lt;a href=&quot;http://www.ahay.org/wiki/Reproducible_Documents&quot; rel=&quot;nofollow&quot;&gt;studies&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A lot of new processing methods are developed within the Seismic Unix and Madagascar groups, and they are great sources if one needs a special tool for a special problem. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The packages are free and are widely used by universities, but they can also be useful for processing companies. It is easy to share or sell projects if they are built in code that everyone have access too. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the processing capabilities are superior or not is generally about opinion, but at least the results can compare well with commercial packages. Sometimes they can be used in the same workflow, e.g. the geometry might be easier to do with a GUI but processing might be just as easy in a script. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My own experience is that the learning curve is rather steep in the beginning, but once you understand the basic tools, Seismic Unix and Madagascar are just as easy, or even easier to work with. Especially if there is a problem or you need to do something unconventional with the data. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastActivityDate="2016-08-09T09:06:09.763" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8539" PostTypeId="2" ParentId="8532" CreationDate="2016-08-09T09:10:42.613" Score="6" Body="&lt;p&gt;I found a great paper named &lt;a href=&quot;http://www.nsstc.uah.edu/sundar/papers/2009/AWMA-proof.pdf&quot; rel=&quot;nofollow&quot;&gt;Remote Sensing of Particulate Pollution from Space: Have We Reached the Promised Land?&lt;/a&gt; and collected some remote sensing instruments doing CH4 measurement in the chart below.       &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It contains the information about the satellite, orbit types, instrument and the data time-range.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Satellite       Orbit       Instrument    Years&#xA;&#xA;Nimbus-7        Polar       SAMS          1978-1983     &#xA;UARS            L56.9       CLAES         1991-1993     &#xA;UARS            L56.9       HALOE         1991-2005     &#xA;ADEOS           PS          IMG           1996-1997     &#xA;Terra           PS          MOPITT        1999-            &#xA;AQUA            PS          AIRS          2002-            &#xA;AURA            PS          HRDLS         2003-            &#xA;Envisat         PS          SCIAMACHY     2007-            &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="595" LastEditDate="2016-09-28T12:53:46.963" LastActivityDate="2016-09-28T12:53:46.963" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8540" PostTypeId="2" ParentId="8213" CreationDate="2016-08-09T10:04:20.217" Score="2" Body="&lt;p&gt;As often in geology of any scale, the surface is only a manifestation of a 3-dimensional body. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's typical for igneous rocks (e.g. granite see &lt;a href=&quot;http://www.oldearth.org/curriculum/geology/images/Rapakivigranite_ss.jpg&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;) that the polished surface have the &lt;a href=&quot;https://en.wikipedia.org/wiki/Voronoi_diagram&quot; rel=&quot;nofollow&quot;&gt;Voronoi&lt;/a&gt;-like-pattern. The minerals grow from a nucleus until they reach the next crystal and the melt is finished. Every point in the rock can be related back to its closest crystal nucleus, depending on the solidus conditions for the chemical composition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Check this short &lt;a href=&quot;https://www.youtube.com/watch?v=tLGBa4tkiJI&quot; rel=&quot;nofollow&quot;&gt;animation&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see the same pattern in the microstructure of metals, e.g. ferrite and pearlite in steel &lt;a href=&quot;https://www.researchgate.net/profile/Wang_Youde/publication/279457723/figure/fig1/AS:294271627350019@1447171231870/Fig-1-Microstructure-of-Q235-steel-material-White-part-is-ferrite-and-black-part-is.png&quot; rel=&quot;nofollow&quot;&gt;e.g. here&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastActivityDate="2016-08-09T10:04:20.217" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8541" PostTypeId="1" AcceptedAnswerId="8550" CreationDate="2016-08-09T11:52:11.097" Score="6" ViewCount="129" Body="&lt;p&gt;I'm working with a distributed snow model which simulates Snow Depth and Snow Cover area. It takes in input some atmospherics variables : Temperature / Precipitation / Wind speed ... &#xA;I want to assimilate the output : Snow Depth retrieving remote sensing data ( I have snow cover indices for each 10 days ) and by using Kalman Filter. But some ambiguities that prevent me to do it : &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;I implemented equation (2a) and (2b), but I have no idea how to implement the model operator &lt;em&gt;M&lt;/em&gt; quoted in equation (3)... If you have any idea or document that describes carefully this operator please provide it to me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NdDC8.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NdDC8.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6364" LastEditorUserId="111" LastEditDate="2016-08-12T16:19:16.207" LastActivityDate="2016-11-02T14:17:20.303" Title="Kalman - Data assimilation with external model" Tags="|models|climate-models|data-analysis|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8542" PostTypeId="1" AcceptedAnswerId="8547" CreationDate="2016-08-09T12:47:39.173" Score="3" ViewCount="117" Body="&lt;p&gt;Earths' crust is usually not exposed. Above-water portion is covered with soil, and Underwater portions are covered with various deposits or sediments. Oceans contain Pelagic sediments.(I don't know whether this underwater sediment considered as soil or not).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The soft cover is probably not being considered as Crust. Some sources telling it &#xA;&lt;strong&gt;pedosphere&lt;/strong&gt; (soil-sphere), but with pictures of only terrestrial soil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;But it is not clear to me&lt;/strong&gt; :  exact how-much portion is being called &lt;strong&gt;pedosphere&lt;/strong&gt;? Is it the &lt;strong&gt;whole&lt;/strong&gt; skin of Earth (&lt;strong&gt;including&lt;/strong&gt; &lt;strong&gt;underwater&lt;/strong&gt;-depositions)? If not; then&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;what is the correct term for the &lt;strong&gt;complete&lt;/strong&gt; soft-layer on Earth? &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Is there any term for part-of skin-of-Earth which is &lt;strong&gt;beneath water&lt;/strong&gt;?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerDisplayName="user6419" LastActivityDate="2016-08-10T08:55:09.050" Title="What would be the correct terminology for soft cover on crust?" Tags="|soil|crust|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8543" PostTypeId="1" CreationDate="2016-08-09T14:56:58.393" Score="1" ViewCount="109" Body="&lt;p&gt;Much googling has not left me any the wiser, so here goes. Let FM be the distance between the mouths of two rivers X and Y. Let NS be the distance between the sources of the same two rivers X and Y. What pair of two rivers X and Y on Earth will produce the biggest quotient FM/NS? Or the smallest?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Two candidates for the biggest might be Indus and Brahmaputra but I am sure there are others.&lt;/p&gt;&#xA;" OwnerUserId="6431" LastActivityDate="2016-08-19T23:27:45.060" Title="Quotient farthest mouths/nearest sources" Tags="|geography|rivers|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8544" PostTypeId="5" CreationDate="2016-08-09T16:05:39.237" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2016-08-09T16:05:39.237" LastActivityDate="2016-08-09T16:05:39.237" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8545" PostTypeId="4" CreationDate="2016-08-09T16:05:39.237" Score="0" Body="For questions concerning or related to subjects, locations, and fields focused on the country of Canada" OwnerUserId="5536" LastEditorUserId="5536" LastEditDate="2016-08-09T20:29:52.600" LastActivityDate="2016-08-09T20:29:52.600" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8546" PostTypeId="2" ParentId="8543" CreationDate="2016-08-10T01:28:28.783" Score="1" Body="&lt;p&gt;Tbb is correct. The 'Congo and Nile' is by far the winner. Their mouths are 4600 km apart, whereas if you trek into the Rwenzori mountains, Western Uganda, there is s small highland swamp in a saddle point on the Congo-Uganda watershed. On either side there are several points where you can claim to be 'at the source', where you can stand with one foot in the Congo basin and the other foot in the Nile basin. The Indus and Brahmaputra are less than half this distance apart.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the other extreme, it's impossible to say. There are several rivers which end at more or less the same place. One then has to argue, 'Is one river a tributary of the other, or not?'&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-10T01:28:28.783" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="8547" PostTypeId="2" ParentId="8542" CreationDate="2016-08-10T07:35:35.360" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;what is the correct term for the complete soft-layer on Earth?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Sediments.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is there any term for part-of skin-of-Earth which is beneath water?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Marine sediments.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The soft cover is probably not being considered as Crust&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It is definitely part of the crust. When discussing mantle-crust issues, then crust is usually in the context of crystalline rocks, but it depends on context.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;But it is not clear to me : exact how-much portion is being called pedosphere? Is it the whole skin of Earth (including underwater-depositions)?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Pedosphere refers to terrestrial soil and sediments, and it usually discussed in context with other &quot;spheres&quot; such as atmosphere and lithosphere. Sediments (and marine sediments) is a neutral term.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As always, in Earth Sciences, there are several terms for the same thing. There is no &quot;correct&quot; term, just &quot;better&quot; when discussing said thing in various circles.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-08-10T07:35:35.360" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8548" PostTypeId="2" ParentId="8542" CreationDate="2016-08-10T08:55:09.050" Score="0" Body="&lt;p&gt;A term more inclusive by not being focused on soil forming processes might be &lt;a href=&quot;https://en.wikipedia.org/wiki/Regolith&quot; rel=&quot;nofollow&quot;&gt;Regolith&lt;/a&gt;. The originial definition according to the source you find on the Wiki page:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In places this covering is made up of material originating through rock-weathering or plant growth in situ. In other instances it is of fragmental and more or less decomposed matter drifted by wind, water or ice from other sources. This entire mantle of unconsolidated material, whatever its nature or origin, it is proposed to call the regolith.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As Michael points out Earth Sciences disciplines come up with definitions according to their needs, in the German Wikipedia you can find a list of &lt;a href=&quot;https://de.wikipedia.org/wiki/Liste_der_Erdsph%C3%A4ren&quot; rel=&quot;nofollow&quot;&gt;definitions of earths spheres&lt;/a&gt; , many of them overlapping.&lt;/p&gt;&#xA;" OwnerUserId="2861" LastActivityDate="2016-08-10T08:55:09.050" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8549" PostTypeId="2" ParentId="6503" CreationDate="2016-08-10T17:58:38.793" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Can volcanos change the climate?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes, but it has to be a very big one, like once every 100,000 years, perhaps every million years.   The volcanic eruption of 75,000 years ago may have kickstarted, or assisted the onset of the last ice age, though debates on that remain unresolved.   It may have also threatened the survival of the human race and caused extensive ecological disasters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;https://en.wikipedia.org/wiki/Toba_catastrophe_theory&quot; rel=&quot;nofollow&quot;&gt;Toba Catastrophy Theory&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I have heard politicians claiming that volcanoes are the sole cause of&#xA;  global warming and using so called &quot;NASA data&quot; to show that the Earth&#xA;  is actually cooling instead of warming.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;All of this is wrong on so many levels.  Volcanoes are a very small contributor of CO2 and they make it colder on average, not warmer.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;While the nature of this site is for specific questions and not for&#xA;  political debate, we all know from the Year Without a Summer that&#xA;  volcanic gases can impact the weather severely making it very cold or&#xA;  hot.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Most volcanic eruptions have very little effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mt. Pinatubo in 1991 is thought to have cooled the planet for a couple of years, by maybe 1/2 of 1 degree, if that.   Mt. Tambora in 1815 was much larger and had a more drastic cooling effect, but only for a few years and only one year was the year without summer.  The reason for this is the cooling volcanic gas and particulates, primarily SO2, has a very short half life in the atmosphere.  By some estimates, it's half life is as short as a few days, though for larger amounts, because it primarily rains out of the atmosphere, the half life might be longer for big eruptions.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://books.google.com/books?id=D_Z2ZAZkuI0C&amp;amp;pg=PA68&amp;amp;lpg=PA68&amp;amp;dq=half%20life%20of%20SO2%20in%20the%20atmosphere&amp;amp;source=bl&amp;amp;ots=ksja3TK93M&amp;amp;sig=UsL1wHW8kZbhnltpg5xCQJE1LIE&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwiBxbvh8rbOAhVM7WMKHW2-BiIQ6AEIRDAG#v=onepage&amp;amp;q=half%20life%20of%20SO2%20in%20the%20atmosphere&amp;amp;f=false&quot; rel=&quot;nofollow&quot;&gt;Source&lt;/a&gt; and &lt;a href=&quot;http://link.springer.com/article/10.1007/BF01592934&quot; rel=&quot;nofollow&quot;&gt;Source&lt;/a&gt;.  (best sources I could find with a quick google search).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's an interesting question as to why Volcanoes are as good at cooling the earth as they are, given that SO2 has a half life of just days, but the answer to this is at least in part, that only very large volcanoes measurably cool the planet, and it might not take that much SO2 to reflect enough sunlight to cool the earth, at least for a month or two, which might be enough to cause a measured drop in temperature for the year, and in extreme cases, a year without summer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the short answer is that Volcanoes don't heat the Earth, they cool it, and they're not particularly good at cooling it either.  Their effect is usually quite temporary.   If a Volcano is strong enough to stop man made climate change in it's tracks, it would probably also cover half a continent with ash and significantly hurt our food supply for the year and perhaps, remove most of the ozone layer for a time.  The temperature effects would be the least of our problems.   (Hopefully, an eruption like that won't happen for several tens of thousands of years, perhaps a few hundred thousand years, but, a gonzo eruption will happen again at some point, probably not in our lifetime though.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;My question is this:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Can a volcanic eruption, either a single or multiple explosions, be&#xA;  the sole cause of global warming at the planetary scale? Can volcanoes&#xA;  really change the climate so fast, relative to the geological&#xA;  timescale, that they produce the abnormal levels that we see today?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Volcanoes are primarily agents of cooling not warming, so one might be able to trigger an ice age, though warm northern hemisphere summers and the current CO2 levels are unlikely to let an ice age actually take hold, so that's a long shot and it would need to be a huge eruption.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's far more rare for volcanoes to cause warming.   What can happen, if the volcano is large enough is that it could kill much of the plant life on earth and decomposition could lead to an increase in Greenhouse gas, but that would probably be temporary as plant life tends to grow fairly quickly and volcanic ash is actually fairly fertile.   Another way is if the volcano sets fire to a large bed of coal, which is thought to have been the case with the &lt;a href=&quot;http://www.livescience.com/41909-new-clues-permian-mass-extinction.html&quot; rel=&quot;nofollow&quot;&gt;Siberian traps&lt;/a&gt;, mentioned by David Hammen, thought to be the largest extinction in the history of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cooling effect of SO2 and particulates that reflect sunlight away from the earth is short lived.   CO2, in large enough amounts is much longer lasting in the atmosphere, 100 years half life or longer, especially if the oceans start warming and releasing some of their stored CO2, so the burning of an entire bed of coal over half a continent may have added enough CO2 to the air, that once the SO2 and Particulate driven cooling was over, the Earth could have warmed measurably, so, it is possible for a Volcano to cause global warming, but it has to be positioned under a large coal deposit and enormously big.   It's very rare, to say the least.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Generally speaking, anyone who says Volcanoes can cause global warming is either lying or ignorant, but if a volcano is an extinction level event, hundreds of times larger than the one that caused the year without summer, which happens every, Oh, I don't know, once every million to several million years, then such a volcano might trigger global warming, but if that happens, the warming will be years away and very far from our biggest concern.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(too long?)&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2016-08-10T17:58:38.793" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8550" PostTypeId="2" ParentId="8541" CreationDate="2016-08-11T02:04:02.910" Score="8" Body="&lt;p&gt;$M$ is the forward model you are using. It is the dynamical model used to solve whatever discrete equation evolves the field ($d?/dt=$). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The best way to start with data assimilation and understand its nomenclature is to read &lt;a href=&quot;http://twister.caps.ou.edu/OBAN2004/IdeEtal_1997_Notation.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ide et al. (1997)&lt;/a&gt;. In their work, they explain it as: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A discrete model for the evolution of an atmospheric, oceanic, or coupled system from time $t_i$ to time $t_{i+1}$ is governed by an equation &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;$x^f(t_{i+1})=M_i[x^f(t_{i})]$,          (1)&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;where $x$ and $M$ are the model's state vector and its corresponding dynamic operator, respectively. The state vector $x$ has dimension $n$. The dynamics $M$ of the model evolution (1) in a computer simulation or prediction is commonly nonlinear and deterministic, while the true geofluid might differ from (1) by random or systematic errors. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Ide, K., Courtier, P., Ghil, M., Lorenc, A.C., 1997. Unified notation&#xA;for data assimilation: operational, sequential and variational. J.&#xA;Met. Soc. Jpn. 75, 181– 189.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2016-11-02T14:17:20.303" LastActivityDate="2016-11-02T14:17:20.303" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8551" PostTypeId="2" ParentId="8519" CreationDate="2016-08-11T03:48:06.870" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Do you know any climate-based forums on-line that don't focus on our current climate change crisis and allow hard science on fictional climatic patterns?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I wish there was one like that, but if you want quality information you need to reach knowledgeable people, and most of them don't have the time to sit around on these forums. They're too busy doing research. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For specifics, your best bet is the scientific literature, which is vast, but a little Google Scholar goes a long way. You'd be surprised how many PDFs are lying around, away from the journal paywall.  If you have more specific queries (e.g. what is the impact of the closing of the Panama Isthmus on North Pacific overturning circulation?) that would help narrow down the search.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a nice, undergraduate level textbook that does a nice job of presenting big picture climate changes over geologic time, I recommend &quot;Earth's Climate: Past and Future&quot; by William F Ruddiman. &lt;/p&gt;&#xA;" OwnerUserId="6437" LastActivityDate="2016-08-11T03:48:06.870" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8552" PostTypeId="1" AcceptedAnswerId="8553" CreationDate="2016-08-11T08:23:31.477" Score="6" ViewCount="126" Body="&lt;p&gt;In atmospheric dispersion modelling the deposition velocity of particulate matter is often described by:&#xA;$$&#xA;v_d = \frac{1}{r_A+r_B+r_A r_B v_g}+v_g \hspace{10mm}(1)&#xA;$$&#xA;where $r_A$ is the aerodynamic resistance (describing turbulent fluxes in the surface layer), $r_B$ is the viscous resistance (molecular diffusion in the quasi-laminar sublayer) and $v_g$ is the terminal fall velocity of the particles. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How is $(1)$ derived?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is used in numerous models but I haven't found any references explaining how the expression is derived. The closest I've found is in &lt;a href=&quot;https://books.google.se/books?hl=sv&amp;amp;lr=&amp;amp;id=n_RmCgAAQBAJ&amp;amp;oi=fnd&amp;amp;pg=PR23&amp;amp;ots=gQM6KLscgL&amp;amp;sig=UAVnf4v1jDmb_9Jd0cooP8BL_lM&amp;amp;redir_esc=y#v=onepage&amp;amp;q&amp;amp;f=false&quot;&gt;this book by Seinfeld and Pandis&lt;/a&gt; (ISBN: 9781118947401), chapter 19.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There, it is explained that $(1)$ is derived from the following system of equations describing the total flux through an assumed constant flux layer:&#xA;$$&#xA;F&#xA;= \frac{C_3-C_2}{r_A} + v_g C_3&#xA;= \frac{C_2+C_1}{r_B} + v_g C_2&#xA;= \frac{C_3-C_1}{r_t}&#xA;\hspace{10mm} (2)&#xA;$$&#xA;where $C_3$ is the particle concentration at the top of the surface layer, $C_2$ is the concentration between the surface layer and the viscous sublayer and $C_1$ is the concentration of still airborne particles at the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At this stage it is assumed all particles close to the surface will adhere to the surface so that $C_1$ is practically 0. Then $(2)$ can be simplified to:&#xA;$$&#xA;\frac{C_3}{r_t}&#xA;= \frac{C_3-C_2}{r_A} + v_g C_3&#xA;= \frac{C_2}{r_B} + v_g C_2&#xA;\hspace{10mm} (3)&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By elimination of $C_3$ and $C_2$ from $(3)$ one is supposed to end up with $(1)$, since $v_d=r_t^{-1}$. I've tried doing this but end up with this instead:&#xA;$$&#xA;v_d = \frac{1}{r_t}&#xA;= \frac{1}{r_A+r_B+r_A r_B v_g} + \frac{v_g}{r_A(\frac{1}{r_B}+v_g) +1}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So either my algebra is a bit rusty or there are additional assumption involved...&lt;/p&gt;&#xA;" OwnerUserId="2505" LastActivityDate="2016-08-11T10:34:15.903" Title="How to derive the (dry) deposition velocity for particles in the atmosphere" Tags="|meteorology|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8553" PostTypeId="2" ParentId="8552" CreationDate="2016-08-11T10:34:15.903" Score="4" Body="&lt;p&gt;After some more work I got it working, this might not be the shortest solution possible. There are no further assumptions needed, just pure algebra.&#xA;The solution is a bit tedious to reach, so it's not too surprising that this is usually not included in the literature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Start by splitting $(3)$ into two separate equations&#xA;$$&#xA;\begin{cases}&#xA;\frac{C_3}{r_t}=\frac{C_3-C_2}{r_a}+v_g C_3\hspace{10mm}(4)\\&#xA;\frac{C_3}{r_t}=\frac{C_2}{r_b}+v_g C_2\hspace{17mm}(5)&#xA;\end{cases}&#xA;$$&#xA;Get $C_3$ by multiplying $(5)$ with $r_t$ and breaking out $C_2$:&#xA;$$&#xA;C_3 = C_2 r_t (\frac{1}{r_b} + v_g)\hspace{10mm}(6)&#xA;$$&#xA;Divide $(4)$ by $C_3$:&#xA;$$&#xA;\frac{1}{r_t}=\frac{1-C_2/C_3}{r_a}+v_g\hspace{10mm}(7)&#xA;$$&#xA;Insert $(6)$ in $(7)$:&#xA;$$&#xA;\frac{1}{r_t}&#xA;=\frac{1-\frac{C_2}{C_2r_t(1/r_t+v_g)}}{r_a}+v_g &#xA;=\frac{ \frac{1}{r_b}+v_g-\frac{1}{r_t} }{ r_a(\frac{1}{r_b}+v_g)}+v_g&#xA;\hspace{10mm}&#xA;$$&#xA;Move $r_t$ to LHS, i.e. add $\left(r_t \cdot r_a(\frac{1}{r_b}+v_g)\right)^{-1}$ to both sides:&#xA;$$&#xA;\frac{1}{r_t}\left(1 + \frac{1}{r_a(\frac{1}{r_b}+v_g)}\right)&#xA;= \frac{1}{r_a}+v_g&#xA;$$&#xA;Divide by $\left(1+\frac{1}{r_a(\frac{1}{r_b}+v_g)} \right)$ on both sides:&#xA;$$&#xA;\frac{1}{r_t}&#xA;=\frac{1/r_a+v_g}{\left(1+\frac{1}{r_a(\frac{1}{r_b}+v_g)} \right)}&#xA;$$&#xA;Multiply numerator and denominator (RHS) by $r_a$ and simplify:&#xA;$$&#xA;= \frac{1+v_g r_a}{\left(r_a+\frac{1}{(\frac{1}{r_b}+v_g)} \right)}&#xA;= \frac{1+v_g r_a}{\left(r_a\frac{(\frac{1}{r_b}+v_g)}{(\frac{1}{r_b}+v_g)}+\frac{1}{(\frac{1}{r_b}+v_g)} \right)}&#xA;= \frac{(1+v_gr_a)(\frac{1}{r_b}+v_g)}{r_a(\frac{1}{r_b}+v_g)+1}&#xA;$$&#xA;Re-organize the numerator and split it:&#xA;$$&#xA;=\frac{ \frac{1}{r_b}+v_g+v_g\frac{r_a}{r_b} +v_g^2 r_a }{r_a(\frac{1}{r_b}+v_g)+1}&#xA;=\frac{ \frac{1}{r_b}+v_g\left(r_a(\frac{1}{r_b} +v_g)+1\right) }{r_a(\frac{1}{r_b}+v_g)+1}&#xA;=\frac{ \frac{1}{r_b}}{r_a(\frac{1}{r_b}+v_g)+1} + v_g&#xA;$$&#xA;If we now move $r_b$ in the first term on the RHS to the denominator we end up with the final expression:&#xA;$$&#xA;\frac{1}{r_t} = \frac{1}{r_a + r_b + r_a r_b v_g } + v_g&#xA;$$&lt;/p&gt;&#xA;" OwnerUserId="2505" LastActivityDate="2016-08-11T10:34:15.903" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8554" PostTypeId="2" ParentId="2715" CreationDate="2016-08-11T15:30:50.697" Score="4" Body="&lt;p&gt;The reason Earth has so much nitrogen is because it is non reactive and builds up. The origin of the nitrogen is covered in previous answers. Also, Venus has as much nitrogen in its atmosphere as Earth, but it is a much smaller percentage due to the large amount of CO2. Here is a nice graph showing what gases can exist in a planetary atmosphere based on temperature and escape velocity (mass/radius) of a planet &lt;a href=&quot;http://abyss.uoregon.edu/~js/ast121/lectures/lec14.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://abyss.uoregon.edu/~js/ast121/lectures/lec14.html&lt;/a&gt; .&lt;/p&gt;&#xA;" OwnerUserId="4600" LastEditorUserId="63" LastEditDate="2017-04-20T13:58:48.773" LastActivityDate="2017-04-20T13:58:48.773" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8555" PostTypeId="2" ParentId="8353" CreationDate="2016-08-11T15:54:44.427" Score="2" Body="&lt;p&gt;You can try if this looks simple enough. Still requires registration, but it is free for reasonable use: &lt;a href=&quot;http://data.planetos.com/datasets/noaa-ncep_gefs:global-ensemble-forecast-system-gefs&quot; rel=&quot;nofollow&quot;&gt;Global Ensemble Forecast System (GEFS)&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="3385" LastEditorUserId="6093" LastEditDate="2016-09-17T20:24:37.797" LastActivityDate="2016-09-17T20:24:37.797" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8556" PostTypeId="2" ParentId="7993" CreationDate="2016-08-11T19:00:12.807" Score="8" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Temperature differences y/y are very small compared to natural variation during the year&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is only saying that we have a large seasonal cycle. It says nothing about low-frequency variations. Once you remove seasonal effects, the centennial scale warming is obvious and nearly ubiquitous (yes, a handful of regions have been cooling recently, but the vast majority are warming).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The correlation between CO2 emissions and measured temperature changes is not perfect. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Who expects it to be perfect? Certainly not climate scientists, for the reasons stated above and also &lt;a href=&quot;http://strangeweather.wordpress.com/2013/04/09/global-warming-does-not-slow-down/&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;. This is a textbook example of a &lt;a href=&quot;http://en.wikipedia.org/wiki/Straw_man&quot; rel=&quot;noreferrer&quot;&gt;straw man&lt;/a&gt;, used ubiquitously by people who cannot make real arguments (like climate &quot;skeptics&quot;)&lt;/p&gt;&#xA;" OwnerUserId="6437" LastActivityDate="2016-08-11T19:00:12.807" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8557" PostTypeId="1" AcceptedAnswerId="8559" CreationDate="2016-08-11T19:12:00.807" Score="11" ViewCount="3126" Body="&lt;p&gt;As I understand it there are two key kinds of air pollution: ozone and fine particles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any long-term data series that chart average ozone levels and/or fine particulates over time going back to 1970?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastEditorUserId="6031" LastEditDate="2019-04-21T05:42:45.897" LastActivityDate="2019-04-21T05:42:45.897" Title="How do current pollution levels in Los Angeles compare to the 1970s?" Tags="|atmosphere|air-pollution|pollution|pm2.5|particulates|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8558" PostTypeId="2" ParentId="8557" CreationDate="2016-08-12T06:30:53.983" Score="10" Body="&lt;p&gt;The air quality in Los Angeles does not meet federal air quality standards.  That being said, the air quality has improved immensely since the 1970s.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the &lt;a href=&quot;http://www.arb.ca.gov/html/brochure/history.htm&quot;&gt;California Air Resource Board&lt;/a&gt;, in 1965 the maximum one-hour ozone concentration was 0.58 ppm.  Since then, that number has come down to about 0.12 ppm.  You can obtain the latest ozone data from &lt;a href=&quot;https://www3.epa.gov/airdata/ad_maps.html&quot;&gt;EPA&lt;/a&gt;.  See a  30 year ozone trend image below from the &lt;a href=&quot;http://www.aqmd.gov/home/library/public-information/2005-news-archives/smog-season-2005&quot;&gt;South Coast Air Quality Management District&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kNGqt.gif&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kNGqt.gif&quot; alt=&quot;ozone history&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Particulate matter is a bit tougher to quantify.  PM10 (coarse and fine particles together) has been tracked since the late 80s, but PM2.5 (fine particles) has only been tracked since 1999.  You can read a bit about it &lt;a href=&quot;http://www.aqmd.gov/home/library/public-information/2005-news-archives/2004-cleanest-year-on-record-for-particulate-pollution&quot;&gt;here&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reduction in particulate matter has not been as dramatic as ozone.  This makes sense, though, since ozone is a secondary pollutant whose precursors (NOx and VOCs) largely come from vehicle tailpipes.  NOx and VOC emissions from vehicles has decreased significantly in recent years, especially with fleet turnover.  In contrast, coarse and fine particulate matter come from many different sources, e.g. road dust, agriculture, cooking, etc. which is difficult to control since rain is the major control method.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2016-08-12T06:30:53.983" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8559" PostTypeId="2" ParentId="8557" CreationDate="2016-08-12T10:12:36.180" Score="8" Body="&lt;p&gt;A figure downloaded from this &lt;a href=&quot;https://eos.org/features/urbanization-air-pollution-now&quot;&gt;site&lt;/a&gt;.        &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It represent the history trends of the pollutants related to the photochemical pollution from 1960s to 2000s  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7B2IB.jpg&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7B2IB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can find that $O_3$, $PAN$, $VOCs$, $NO_x$ have all declined. And O3 variation trends were strongly correlated to $NO_x$ which can be explained by the VOC-NOx chemistry.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another material I have searched out was a class lecture downloaded &lt;a href=&quot;http://www.sjsu.edu/people/frank.freedman/courses/metr113/s1/Met113_Spring11_Lect1.pdf&quot;&gt;here&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It introduced the contents below:      &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;- Air Pollution Regulation: Pre Clean Air Act 1970&#xA;- Air Pollution: Definition, Concentration, Standards&#xA;- Clean Air Act 1970&#xA;- Local Agencies (California &amp;amp; Bay Area)  &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The lecture has depict the air pollution trends and regulation situation from 1950s till 2000s.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;May it help!&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="5214" LastEditDate="2016-08-12T10:19:10.377" LastActivityDate="2016-08-12T10:19:10.377" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8560" PostTypeId="2" ParentId="8537" CreationDate="2016-08-12T15:39:30.063" Score="1" Body="&lt;p&gt;The effect of atmospheric pressure on sea level is described as &lt;a href=&quot;https://earthscience.stackexchange.com/questions/5129/what-is-the-inverted-barometer-effect&quot;&gt;&quot;inverted barometer&quot; effect&lt;/a&gt;. The basic equation governing the effect (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/96RG03037/pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wunsch &amp;amp; Stammer, 1997&lt;/a&gt;) is: $\delta_{IB}  = -{\Delta P_{atm} \over  \rho_{water}*g}$, where $\delta_{IB}$ is the change in sea level, $\Delta P_{atm}$ is the change in atmospheric pressure, and $\rho_{water}$ is the density of water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good example of the effect was observed by &lt;a href=&quot;http://www.jstor.org/stable/1779861&quot; rel=&quot;nofollow noreferrer&quot;&gt;Close (1918)&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/0abvy.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0abvy.png&quot; alt=&quot;Inverted barometer from Wunsch&amp;amp;Stammer, 1997 reproduction of Close, 1918&quot;&gt;&lt;/a&gt; From &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/96RG03037/pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wunsch &amp;amp; Stammer, 1997&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In reality, while atmospheric pressure can vary between 870 and 1070 mb, the problem is that it might result in a change of 2m over a distance between high and low pressures that could be many hundreds of km. By comparison, the sea level gradient across the Gulf Stream is on the order of 1m/100km. The other problem is that the ocean adjusts dynamically to the differences in air pressure and the resulting sea level gradient might be smaller.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To convert pressure to force (acceleration), you can use $P=\rho g h$. The biggest differences in &lt;a href=&quot;https://en.wikipedia.org/wiki/Gravity_of_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;$g$ at the surface of Earth&lt;/a&gt; are around 50 &lt;a href=&quot;https://en.wikipedia.org/wiki/Gal_(unit)&quot; rel=&quot;nofollow noreferrer&quot;&gt;mgal&lt;/a&gt; (50 $\mu m/s^2$) and &lt;a href=&quot;https://en.wikipedia.org/wiki/Gravity_of_Earth#Variation_in_gravity_and_apparent_gravity&quot; rel=&quot;nofollow noreferrer&quot;&gt;caused by differences in latitude, altitude, and local topography and geology&lt;/a&gt;. The differences in gravity cause by the extra meter of water will be way smaller and can be considered negligible.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Wunsch, C., and D. Stammer (1997), Atmospheric loading and the oceanic “inverted barometer” effect, Rev. Geophys., 35(1), 79–107, doi:10.1029/96RG03037.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Close, C. (1918), The Fluctuations of Mean Sea-Level with Special Reference to Those Caused by Variations in Barometric Pressure. The Geographical Journal 52, no. 1, 51-58.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-08-12T15:39:30.063" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8561" PostTypeId="1" CreationDate="2016-08-12T16:08:39.087" Score="7" ViewCount="379" Body="&lt;p&gt;Air quality forecasting  models which are useful for atmospheric scientist and government can be built based on numerical theory or statistic theory.     &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first approach outline the basic physics &amp;amp; dynamic process, chemical reaction of true atmosphere and the various kind of emission. The second approach use statistical tools to capture the pattern of historical meteorology, air quality dataset and train a predictive model. With evaluating the model for unseen data instances predicting, it can be used for air quality forecasting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many researchers choose numerical models to achieve their target as computation results based on the emulation of real world, could reproduce spatial-temporal variation of pollutants to some extent.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Machine learning is becoming the cutting-edge of data science even in all scientific field and showing its great ability in non-linear problems(secondary pollutants(O3, SOA, etc) are formed through non-linear chemistry reactions).    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the possibilities to use a machine learning approach to improve air quality forecasting?&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="543" LastEditDate="2021-10-06T06:08:05.063" LastActivityDate="2021-10-06T06:08:05.063" Title="What's the prospect of air quality forecasting based on machine learning?" Tags="|atmosphere|air-pollution|numerical-modelling|air-quality|machine-learning|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8562" PostTypeId="1" CreationDate="2016-08-12T18:48:03.993" Score="7" ViewCount="87" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Accumulated_cyclone_energy&quot; rel=&quot;noreferrer&quot;&gt;Accumulated cyclone energy (ACE)&lt;/a&gt; is used to measure and compare the activity of individual hurricanes and entire tropical cyclone seasons. It is calculated as an integral of the squares of hurricane speeds. My question is whether a similar parameter can be used to estimate the activity of any kind of cyclone or storm system (tropical or extra-tropical cyclones, fronts...).&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="192" LastEditDate="2016-08-12T19:02:50.000" LastActivityDate="2016-08-12T19:02:50.000" Title="Using Acummulated Cyclone Energy (ACE) for non-tropical cyclones" Tags="|meteorology|tropical-cyclone|storms|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8564" PostTypeId="1" CreationDate="2016-08-13T11:44:17.883" Score="2" ViewCount="42" Body="&lt;p&gt;Does the Earth's core have the same rotation period as the surface?&lt;/p&gt;&#xA;" OwnerUserId="2819" LastActivityDate="2016-08-13T11:44:17.883" Title="Does the Earth's core have the same rotation period as its surface?" Tags="|geology|core|" AnswerCount="0" CommentCount="1" ClosedDate="2016-08-14T01:20:48.227" ContentLicense="CC BY-SA 3.0" />
  <row Id="8565" PostTypeId="1" CreationDate="2016-08-13T04:14:19.327" Score="5" ViewCount="205" Body="&lt;p&gt;For our assignment, we are required to analyse and compare the $\ce{CO2}$ level (in both ocean and air) of two different sites. Theoretically, shouldn't the $\ce{CO2}$ level of a colder region (e.g., Alaska) be higher due to $\ce{CO2}$ being more soluble in colder temperatures? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've looked at the data (I'm comparing Alaska and the Equator) and the carbon dioxide concentration is higher for the equator. What could explain this? The data can be found at NOAA's &lt;a href=&quot;http://www.pmel.noaa.gov/co2/map/text&quot; rel=&quot;nofollow noreferrer&quot;&gt;PMEL Carbon Data Observation Data page&lt;/a&gt;.&lt;sup&gt;*&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;* The US National Oceanic and Atmospheric Administration / Pacific Marine Environmental Laboratory&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="Lisa Ban " LastEditorUserId="6129" LastEditorDisplayName="user7009" LastEditDate="2020-05-07T11:22:29.360" LastActivityDate="2020-05-07T13:40:19.720" Title="Carbon dioxide and ocean acidification based on temperature" Tags="|oceanography|temperature|co2|homework|carbon-cycle|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8566" PostTypeId="2" ParentId="8353" CreationDate="2016-08-14T13:10:47.087" Score="2" Body="&lt;p&gt;For the historic forecasts check out the &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/model-data/model-datasets/global-ensemble-forecast-system-gefs&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Ensemble Forecast System (GEFS)&lt;/a&gt; from NOAA. It has historic forecasts going back to 2015. For validation try &lt;a href=&quot;https://daymet.ornl.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Daymet&lt;/a&gt; (North American only) or PRISM (continental USA only) for gridded temperature and precip from historic observations.&lt;/p&gt;&#xA;&lt;p&gt;The GEFS data is in GRIB format. But thats just something you can't get around. The European climate center (ECMWF) have their own suite of commands in a program called &lt;code&gt;grib_api&lt;/code&gt;, which includes a handy GRIB to netCDF converter if that's a format your more familiar with.&lt;/p&gt;&#xA;&lt;p&gt;All of these are free to download without signing up for anything. PRISM has it's own R package &lt;code&gt;prism&lt;/code&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The GEFS data was previously available through the R package &lt;code&gt;rnoaa&lt;/code&gt;, but this functionality has been dropped. You can try the &lt;a href=&quot;https://github.com/FLARE-forecast/Rnoaa4cast&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;code&gt;Rnoaa4cast&lt;/code&gt;&lt;/a&gt; and the &lt;a href=&quot;https://github.com/rqthomas/noaaGEFSpoint/&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;code&gt;noaaGEFSpoint&lt;/code&gt;&lt;/a&gt; packages package.&lt;/p&gt;&#xA;" OwnerUserId="6316" LastEditorUserId="174" LastEditDate="2022-11-28T19:42:13.593" LastActivityDate="2022-11-28T19:42:13.593" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="8567" PostTypeId="1" CreationDate="2016-08-15T00:12:12.803" Score="5" ViewCount="92" Body="&lt;p&gt;I am trying model to some snow processes for the whole US. &#xA;I do have daily climate forcing time series for a 1 x 1 km raster in a Lambert Conformal Conic Projection (netCdf format). The MODIS snow cover time series for a grid of 500 m in a sinusoidal projection (hdf format) and snow depth data in a 1 km resolution grid (binary .dat file) in a Geographical projection. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to get the time series for each variable in a 1x1 and 2x2 km grid. &#xA;The question I have is how can this be achieved without using GIS Software. I know how to do this using ArcGIS, but since I do have a lot of files I think there must be a better way of doing this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My model is in MATLAB, so if there is some toolbox that would achieve that it would be my first choice. However, I am open to other approaches and standalone tools. &lt;/p&gt;&#xA;" OwnerUserId="6454" LastEditorUserId="6454" LastEditDate="2016-08-15T01:59:30.703" LastActivityDate="2016-08-15T04:29:03.570" Title="snow modelling using raster data with different resolution" Tags="|climate|models|water|snow|" AnswerCount="1" CommentCount="3" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8568" PostTypeId="2" ParentId="8567" CreationDate="2016-08-15T04:29:03.570" Score="2" Body="&lt;p&gt;To make sure I'm understanding correctly: You need to reproject some data from one coordinate system to another. Then you need to interpolate or resample it onto a grid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are already familiar with MATLAB, then you can certainly use MATLAB. Look to the Mapping Toolbox for coordinate transforms (although it does not make life easy IMHO), and check out &lt;code&gt;griddedInterpolant&lt;/code&gt; and &lt;code&gt;scatteredInterpolant&lt;/code&gt; and their options for interpolation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you're more tool-agnostic it might be easier in R (check out the &lt;code&gt;spatial&lt;/code&gt;, &lt;code&gt;raster&lt;/code&gt;, and &lt;code&gt;rgdal&lt;/code&gt; packages). Or, depending on your GIS system, there is probably a way to script or automate it there so that you do not have to work through the process manually for all your files.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2016-08-15T04:29:03.570" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8569" PostTypeId="1" AcceptedAnswerId="8572" CreationDate="2016-08-15T04:43:21.670" Score="4" ViewCount="2113" Body="&lt;p&gt;It is common to describe tidal elevations at a given location by giving the phases and amplitudes of tidal constituents. One such application is for setting the open boundary conditions for regional flow models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the phase of a constituent is only meaningful if we also know a specific time at which that phase angle applies. For example, if a constituent has an amplitude of 2m and a phase of 127 degrees (perhaps more accurately called a phase offset), there must be a specific date and time at which it is at 127 degrees, from which it progresses at a rate specified by the period of that constituent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a convention as to what date and time this is?&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="111" LastEditDate="2016-08-16T11:25:37.903" LastActivityDate="2016-08-25T23:09:35.397" Title="When specifying phase and amplitude for a tidal constituent, what date/time does phase start from?" Tags="|ocean|sea-level|tides|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8570" PostTypeId="1" AcceptedAnswerId="8571" CreationDate="2016-08-15T07:29:24.607" Score="7" ViewCount="600" Body="&lt;p&gt;I was reading Planning Commission report of Five Year plan (2012-2017) of India, and in the context of Inter-linking of rivers it is mentioned that :&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The presence of a low salinity layer of water with low density is a reason for maintenance of high sea-surface temperatures (greater than&#xA;  28 degrees C) in the Bay of Bengal, creating low-pressure areas and&#xA;  intensification of monsoon activity.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So how does salinity and density affects SST?&lt;/p&gt;&#xA;" OwnerUserId="2756" LastActivityDate="2016-08-16T15:05:30.223" Title="How does salinity and density affects sea surface temperature?" Tags="|ocean|oceanography|salinity|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8571" PostTypeId="2" ParentId="8570" CreationDate="2016-08-15T11:14:20.273" Score="5" Body="&lt;p&gt;A low salinity layer that is associated with low density (assuming the same temperature) will remain on top of the water column. As such the water will be able to get warmer and the difference in salinity and temperature will make it even more difficult to mix it down with the rest of the water column. So the combination of high temperature and low salinity results in even lower densities. You can play with the relationship using &lt;a href=&quot;http://www.mt-oceanography.info/Utilities/density.html&quot;&gt;http://www.mt-oceanography.info/Utilities/density.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2016-08-15T11:14:20.273" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8572" PostTypeId="2" ParentId="8569" CreationDate="2016-08-15T14:26:28.770" Score="3" Body="&lt;p&gt;Tidal constituents follow the expression: &lt;span class=&quot;math-container&quot;&gt;$\eta(t) = A cos (\omega t + \phi)$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$\eta$&lt;/span&gt; is the tidal elevation at a specific time, &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; is the amplitude of the constituent, &lt;span class=&quot;math-container&quot;&gt;$\omega$&lt;/span&gt; is the speed of the constituent (the rate of change in phase), and, finally &lt;span class=&quot;math-container&quot;&gt;$\phi$&lt;/span&gt; is the phase of the constituent at the initial time from which the time is measured. The phase, &lt;span class=&quot;math-container&quot;&gt;$\phi$&lt;/span&gt;, is measured with regard to the &lt;a href=&quot;http://www.vims.edu/research/units/labgroups/tc_tutorial/static.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;equilibrium tide&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Thus, the short answer is that the phase is usually referring to the delay (in degree) from the theoretical equilibrium tide. From the &lt;a href=&quot;http://tidesandcurrents.noaa.gov/glossary.html#epoch&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA glossary&lt;/a&gt; for phase lag (or phase epoch, not to be confused with the tidal datum epoch):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Angular retardation of the maximum of a constituent of the observed tide (or tidal current) behind the corresponding maximum of the same constituent of the theoretical equilibrium tide. It may also be defined as the phase difference between a tidal constituent and its equilibrium argument. As referred to the local equilibrium argument, its symbol is &lt;span class=&quot;math-container&quot;&gt;$\kappa$&lt;/span&gt;. When referred to the corresponding Greenwich equilibrium argument, it is called the Greenwich epoch and is represented by &lt;span class=&quot;math-container&quot;&gt;$G$&lt;/span&gt;. A Greenwich epoch that has been modified to adjust to a particular time meridian for convenience in the prediction of tides is represented by &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; or by &lt;span class=&quot;math-container&quot;&gt;$\kappa'$&lt;/span&gt;. The relations between these epochs may be expressed by the following formula:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$G = \kappa + pL$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$g = \kappa' = G – aS / 15$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;in which &lt;span class=&quot;math-container&quot;&gt;$L$&lt;/span&gt; is the longitude of the place and &lt;span class=&quot;math-container&quot;&gt;$S$&lt;/span&gt; is the longitude of the time meridian, these being taken as positive for west longitude and negative for east longitude; &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; is the number of constituent periods in the constituent day and is equal to 0 for all long-period constituents, 1 for diurnal constituents, 2 for semidiurnal constituents,and so forth; and a is the hourly speed of the constituent, all angular measurements being expressed in degrees.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="111" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-08-15T14:26:28.770" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8573" PostTypeId="1" AcceptedAnswerId="8574" CreationDate="2016-08-16T05:44:25.060" Score="4" ViewCount="160" Body="&lt;p&gt;Is the iron in the inner core of Earth trapped forever? Are there any mechanisms that allow some iron to leave the core and come to the surface (eg: magma convention)?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="6298" LastEditDate="2016-08-16T09:05:23.013" LastActivityDate="2016-08-16T14:50:55.887" Title="Does iron in core have chance to come out to crust?" Tags="|core|geologic-layers|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8574" PostTypeId="2" ParentId="8573" CreationDate="2016-08-16T14:50:55.887" Score="7" Body="&lt;p&gt;No, we occasionally get fragments of upper mantle overthrust onto the Earth's crust, but then the specific gravity (density) contrast is not so great, roughly 2.7 to 3.0 for crust, about 3.2 for mantle. But the core is another matter. The density contrast is huge - the liquid outer core is between 9.9 and 12.2, whilst the solid core is estimated to be 12.6 to 13.0! (High pressure iron-nickel with some denser metals mixed in). Not only that, but the mantle is quite close to the surface, only tens of kilometres deep, whereas the Earth's core is 3000 kilometres below the surface. &#xA;Sadly, there is no volcanic process that comes from even remotely that depth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alas - many geologists, myself included, would dearly love to sample the core and compare the composition to iron meteorites (assumed similar). There are many other questions of geochemistry and isotopic composition which might be answered if only we could sample that deep. Unfortunately it is way beyond even the most optimistic advances in technology, so we just have to theorize.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-16T14:50:55.887" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8575" PostTypeId="2" ParentId="8570" CreationDate="2016-08-16T15:05:30.223" Score="2" Body="&lt;p&gt;The Planning Commission report is correct. The combined Ganges - Meghna-Brahmaputra rivers all flow from out of the same delta (mostly in Bangladesh), and float as a lower salinity, more buoyant layer out into the Bay of Bengal, certainly for hundreds of kilometres, maybe for more than a thousand. Wind turbulence, sea currents, and diffusion eventually cause the low and high-salinity water to mix, but it's a slow process. Moreover, nearly all the sun's radiant heat is concentrated in the topmost 20 to 30 metres, thereby warming and expanding the  water to give even more buoyancy. Global warming will amplify the density contrast still further, so I very much doubt if the proposals to divert some of the flood waters into dry land areas will do much to reverse the trend. But some oceanic modelling should elucidate the matter further.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This raises an interesting point. How closely does the current generation of Ocean-Atmosphere-Coupled Global Climatic Models capture the physics of thermal buoyancy in the Bay of Bengal? Any answers?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-16T15:05:30.223" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8576" PostTypeId="1" CreationDate="2016-08-16T17:05:18.703" Score="4" ViewCount="10146" Body="&lt;p&gt;I am processing a big meteorological data set, which is a global forcings dataset derived by other datasets and observations, and calculating relative humidity from qair,temperature, and pressure according to these formulas &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2360/how-do-i-convert-specific-humidity-to-relative-humidity&quot;&gt;How do I convert specific humidity to relative humidity?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am noticing that I have a lot of occurrences where RH is slightly higher than 100% and I am wondering if this makes sense or not considering this is air temp from 2m, I would expect that near surface RH over 100% is some errors in the data set.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*I am not a climatologist nor a meteorologist, I use this data to study plants, so I hope for a not too technical answer, thank you.&lt;/p&gt;&#xA;" OwnerUserId="3061" LastEditorUserId="15513" LastEditDate="2019-03-25T00:49:18.183" LastActivityDate="2019-03-25T00:49:18.183" Title="Can relative humidity be over 100% near (within 30-60m) the surface?" Tags="|meteorology|humidity|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="8577" PostTypeId="2" ParentId="8576" CreationDate="2016-08-16T20:36:04.533" Score="2" Body="&lt;p&gt;It is reasonable to assume that air (atmosphere) acting as as a solution could become supersaturated with water vapor.  Supersaturation condition is where the air literally contains more water vapor than is needed to cause saturation. How common these conditions might be, I do not know.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="1149" LastEditDate="2016-08-18T23:36:08.783" LastActivityDate="2016-08-18T23:36:08.783" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8578" PostTypeId="1" CreationDate="2016-08-17T09:32:27.127" Score="8" ViewCount="291" Body="&lt;p&gt;I am a Ph.D student in Computer Science and Statistical Genetics. I recently became very interested in climate change, for obvious reasons. I would like to use my solid scientific and statistical background in order to get a good grasp of the models that climate scientists use to generate the dire predictions of global warming, which quickly seem to become reality, and to understand the possible outcomes and their probabilities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a good reference or review, book or paper(s), that could provide a clear, thorough introduction to the field for people like me, who have no background in climate studies but are interested in the technical details?&lt;/p&gt;&#xA;" OwnerUserId="6459" LastEditorUserId="192" LastEditDate="2016-08-17T14:58:47.887" LastActivityDate="2016-11-23T07:30:03.327" Title="Climate change review for a scientist" Tags="|climate|models|reference-request|" AnswerCount="3" CommentCount="4" ClosedDate="2016-11-24T04:17:18.803" ContentLicense="CC BY-SA 3.0" />
  <row Id="8579" PostTypeId="2" ParentId="8578" CreationDate="2016-08-17T11:30:54.483" Score="6" Body="&lt;p&gt;EnergyNumbers suggestion is good, but you can only go so far in reading about it second hand. I suggest that you pick a grid cell of interest, then go to the World Bank's climate change knowledge portal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://sdwebx.worldbank.org/climateportal/index.cfm?page=country_future_climate&amp;amp;ThisRegion=Australia&amp;amp;ThisCcode=WSM&quot; rel=&quot;nofollow&quot;&gt;Climate Change Knowledge Portal&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This gives a good cross section of 16 CMIP-5 AOGCM outputs. Check out the variation, and accuracy of the hindcasts vs evidence-based field instrumental data for the same location. Then you will get a good feel for the strengths and weaknesses of the modelling. Also, remember that water-related parameters are much less accurate to forecast than temperature-related parameters. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="6093" LastEditDate="2016-08-18T06:06:55.727" LastActivityDate="2016-08-18T06:06:55.727" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8581" PostTypeId="2" ParentId="8576" CreationDate="2016-08-18T14:23:25.247" Score="1" Body="&lt;p&gt;The relative humidity is the ratio of the partial vapour pressure of air, to the equilibrium vapour pressure over pure water, at the same pressure - yes, it's slightly pressure dependent.But I would put an emphasis upon '&lt;em&gt;Equilibrium&lt;/em&gt;'. In both physics and chemistry one can get all kinds of bizarre results under non-equilibrium conditions, and &gt;100% RH is one of them. It is just a transient feature caused by rapid changes in temperature, pressure, or absolute vapour pressure, and as such it is not really a genuine meteorological observation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, I advise caution when interpreting RH results. There is often a strong diurnal variation in RH, so if there is a met site taking only one reading a day, it could be unrepresentative of true average conditions. This is not so much a problem in advanced countries, where the measurements are (usually) reliably taken at set times. But it is often wildly misleading in developing countries where the observer may take a reading when/if he/she gets around to it, or maybe fakes the data altogether!&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-18T14:23:25.247" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8584" PostTypeId="1" CreationDate="2016-08-19T02:12:12.743" Score="2" ViewCount="40" Body="&lt;p&gt;I want to calculate difference between initial water content of a soil given that its saturation water content can be found from its type. Is there a way to find initial water content of that soil from methods like curve number method?&lt;/p&gt;&#xA;" OwnerUserId="5557" LastActivityDate="2016-08-19T02:12:12.743" Title="Is there a way to calculate difference initial water content, from curve number method?" Tags="|hydrology|water|soil|agriculture|runoff|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8585" PostTypeId="2" ParentId="8543" CreationDate="2016-08-19T02:14:00.990" Score="1" Body="&lt;p&gt;Geography seems especially prone to problems like this, where the use of seemingly simple terms results in a problem that is &lt;strong&gt;&lt;em&gt;too vague to answer&lt;/em&gt;&lt;/strong&gt; without arbitrary criteria defining them,  and the arbitrariness of the criteria renders the so-called &quot;answer&quot; meaningless.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;'Source' and 'mouth' are too ill-defined to allow an answer that means anything to emerge. (And what about distance? As the geodetic crow flies, or along the river's course?)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any two rivers whose drainage basins border each other can considered to have a 'source' at the same point, meaning NS =0, and the quotient, as defined by the problem, is &lt;em&gt;infinite&lt;/em&gt;, no matter how distant the two rivers' 'mouths'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even if we select some arbitrary point as the 'source' we have the case of the Casiquiare and the Orinoco. The Casiquiare flows out from the Orinoco into the Rio Negro, a tributary of the Amazon. The source of the Casiquiare is the source of the Orinoco no matter where you put it. So, infinity again.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If two rivers share a delta, such as the Ganges and Brahmaputra or the Amazon and Tocatins, they have the same 'mouths' as far as anyone can define so their FM must be 0. But in that case their drainage basins border each other, so FM/NS = 0/0, which is the true answer, &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Undefined&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2016-08-19T23:27:45.060" LastActivityDate="2016-08-19T23:27:45.060" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8587" PostTypeId="1" CreationDate="2016-08-19T22:31:06.987" Score="4" ViewCount="862" Body="&lt;p&gt;Do scientists know if the Chicxulub asteroid disintegrated completely upon impact or if any (large or small) chunks of the asteroid remained intact? If it is possible that a significant fragment of the asteroid survived could it have been preserved until today somehow (i.e. can it be found)? &lt;/p&gt;&#xA;" OwnerUserId="6473" LastActivityDate="2021-02-06T20:46:49.130" Title="Chicxulub Asteroid Remains?" Tags="|geology|natural-disasters|impacts|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8588" PostTypeId="1" AcceptedAnswerId="8593" CreationDate="2016-08-20T03:45:37.437" Score="5" ViewCount="1579" Body="&lt;p&gt;Objects can change in size when their temperature changes. I'm wondering whether the cooling of the earth's core will affect it's size? Or will the change be insignificant due to the elements and states involved or the pressure acting on the core etc.?&lt;/p&gt;&#xA;" OwnerUserId="6474" LastEditorUserId="6474" LastEditDate="2016-08-20T04:51:32.223" LastActivityDate="2016-08-20T20:50:27.323" Title="As the earth's core cools, will the size be affected?" Tags="|temperature|geothermal-heat|core|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8589" PostTypeId="2" ParentId="8588" CreationDate="2016-08-20T15:01:25.377" Score="2" Body="&lt;p&gt;Over the 4.6 billion years of the Earth's evolution, so far, the inner/outer core interface has &quot;cooled&quot; to a mere 6000 deg C. Of course, other things being equal, the core will contract as it cools, but the rate of cooling will be massively delayed by the slow radioactive decay of uranium 235, U 238 and Thorium. Delayed, in fact by many more billion years. The mantle will cool with it, and being plastic, will deform to take up the space of the thermal contraction. However, by the time the radioactive heating decays to much lesser values, the sun will have blown up into the red giant phase. Even if the Earth is not actually engulfed by the expanded sun, it will be so heated that the oceans, and more volatile fractions of the crust will have boiled off into space, to become  part of the enhanced solar wind. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we assume that the Earth's core will eventually cool by 4000 deg C, then Earth will eventually have a reduction in radius of about 10 km (my very rough back of an envelope calculation) from thermal contraction alone. How much of the surface will have boiled off into space by then is anybody's guess. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-20T15:01:25.377" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8590" PostTypeId="1" CreationDate="2016-08-20T16:51:33.470" Score="1" ViewCount="37" Body="&lt;p&gt;I was viewing Google Street View and saw an oddly shaped line of light coming from the clouds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How did this happen?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It probably couldn't be lightning as it appeared over multiple images and is too thick. It also ends in a large flash of light.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Qvngd.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Qvngd.png&quot; alt=&quot;Google Street View&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Use &lt;a href=&quot;https://www.google.com/maps/@37.4362548,-115.4506672,3a,75y,209.71h,112.31t/data=!3m6!1e1!3m4!1sM_9oigJZaE_P717nHwtedA!2e0!7i3328!8i1664?hl=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;this link&lt;/a&gt; to see what I'm talking about.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By the way, this is nearby Area 51 (the camera is looking in the direction of Area 51).&lt;/p&gt;&#xA;" OwnerUserId="5801" LastActivityDate="2016-08-20T16:51:33.470" Title="Beam of light coming from otherwise cloudly" Tags="|clouds|lightning|" AnswerCount="0" CommentCount="2" ClosedDate="2017-03-31T11:09:41.827" ContentLicense="CC BY-SA 3.0" />
  <row Id="8592" PostTypeId="1" CreationDate="2016-08-20T18:32:49.450" Score="6" ViewCount="2486" Body="&lt;p&gt;I noticed on google maps today that the earth has two very distinct regions on which the majority of deserts are located. These fall on the tropic of capricorn and cancer. Illustrated here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VFhq0.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VFhq0.png&quot; alt=&quot; from https://sites.google.com/site/fourbiomes/home/deserts&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What causes this?&lt;/p&gt;&#xA;" OwnerDisplayName="user2687" LastActivityDate="2016-08-29T22:27:35.043" Title="Why do the vast majority of the world's deserts fall on the tropic of capricorn or cancer?" Tags="|geography|desert|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8593" PostTypeId="2" ParentId="8588" CreationDate="2016-08-20T20:50:27.323" Score="2" Body="&lt;p&gt;The cooling of the Earth should affect it's size, everything else being equal.  How much, gets complicated, and there are other factors.  Perhaps the cooling isn't even the biggest one.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looking at a density diagram, (source, &lt;a href=&quot;https://en.wikipedia.org/wiki/Structure_of_the_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hEOtU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hEOtU.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a jump in density between the liquid and solid core, which makes sense.  For the most part, an element in solid state is dense than in liquid state (Ice/Water is a rare exception).   By this table below, the bottom of the liquid core (density 12.2) is less dense than the top of the solid core (12.8).   If we use that as a rule of thumb, that's a 5% increase in density as the phase of the Iron-Nickle-otherstuff transitions from solid to liquid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zFut5.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zFut5.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://pubs.usgs.gov/gip/interior/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source of table&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Running the Math, the radius of the inner core, 1,220 km and outer core, 3,400 km.  Volume = 4/3 πr³, increase the density of the inner core as it solidifies by 5%, you end up with a bit under 3,350 km, or a reduction in volume of about 7.5 billion cubic KM (just by solidifying, not doing temperature yet).    If you remove that much volume from the entire Earth though, it works out to 15 KM.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My guess is that under such high pressure, the temperature contraction would be less, but that's just a guess.  I found a few articles on the subject, pay articles mostly but nothing that neatly estimated temperature to density at 1 million atmospheres or more.   That's the crux of your question, but I couldn't find anything specifically on temperature expansion at those pressures.   I did find (and this is fairly obvious looking at a density of the Earth chart), that pressure determines density far more than temperature, inside the Earth.   We think of solids as mostly incompressible, but that's no longer true with millions of ATMs of pressure.   Solids do measurably compress at those pressures.    &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1111/j.1365-246X.1960.tb00066.x/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; says that pressure, not temperature is the primary driver for the core's density.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Jupiter, as a fun example, &lt;a href=&quot;https://en.wikipedia.org/wiki/Jupiter#Mass_and_size&quot; rel=&quot;nofollow noreferrer&quot;&gt;shrinks about 2 CM per year&lt;/a&gt;.  But much of it's size is gas, not solid, which is much more responsive to temperature changes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's other factors too.  Earth's rotation increases it's volume &quot;slightly&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Radioactive decay both helps maintain the Earth's interior temperature and it also releases gas into the core, mantle and lithosphere as a byproduct of that radiation, primarily Helium and Argon.  (but if I was to guess, I think that's probably a minor factor in overall density and size and I think, ignorable).   Lead is less dense than Uranium, but Calcium is more dense than Potassium, so the decay works both ways for density in that sense.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another factor for overall size is the changes to the lithosphere.   Carbon capture and the formation of Granite over time, as well as the formation of soil, all tends to make the earth's lithosphere more puffy.  But, taking that into account, the earth's Crust is about 30-50 km thick, over land only (29% of the earth).   If we figure the Earth's Crust is about 40% expanded, over the entire earth, that works out to about 4-6 KM crustal expansion due to the oxidation of basalt rock and the formation of continental crust, probably a fair bit less than the contraction over the same period of time.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One rather simple way to measure changes in size of the Earth is to measure it's change in rotation, which slows over time due to the moon, but can also change as a result of structural changes such as Earthquakes, or melting ice and growing oceans.  While this may seem to have nothing to do with your question, Earthquakes are, in a sense, settling of the Earth, and large Earthquakes like the 2011 Japan Earthquake did &lt;a href=&quot;http://news.nationalgeographic.com/news/2011/03/110316-japan-earthquake-shortened-days-earth-axis-spin-nasa-science/&quot; rel=&quot;nofollow noreferrer&quot;&gt;speed up the Earth's rotation&lt;/a&gt; due to the Earth becoming slightly more compact.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think it's likely that the Earth grows more compact over time, but as Gordon Stranger said, it's very slow, and the Sun will go red giant long before the Earth's core is cooled.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How much?   If we say 15 KM due to solidifying the inner core, maybe another 10-15 KM for solidifying of much of the mantle, add (Gordon Stranger's estimate) of 10 KM due to temperature, and maybe add 1-2 KM due to the Earth's rotation slowing . . . that's a hugely ballpark guess, but adds up to about 21-32, but a safer, rounder estimate, maybe 20-40 KM as a bad guess accounting for some settling, but that's if the Earth is allowed to cool on it's own over a long enough period of time, like, I don't know, 50-100 billion years.   That works out to roughly 1/2 of 1%.   Works out to about 1/2 of 1% of it's radius.  Earth's gravity would increase by about 1% as a result, 1.5% near the equator.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope that wasn't too much guessing.  This might be a tough one to get a definitive answer on, but I'm pretty sure you're right that contraction is the overall direction.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2016-08-20T20:50:27.323" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8594" PostTypeId="1" AcceptedAnswerId="8625" CreationDate="2016-08-20T21:44:27.787" Score="3" ViewCount="1168" Body="&lt;p&gt;I understand about physic and waves, but I am a totally rookie in this topic. I was wondering which are the typical frequency ranges of the S-waves, P-waves and surface waves. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My idea would be to detect any seismic event using Software Defined Radio, but I am not sure at all If any peripheral could detect these kind of waves properly. For example, a HackRF peripheral works between 1 MHz to 6 GHz. And, as far as I know, lower frequencies below 3MHz travel efficiently as ground waves. Because of that I was wondering If I could detect anything through Medium Frequencies (0.3 to 3 MHz). For example, a HackRF would detect between 1 MHz to 6 GHz operating frequency, so it may detect something, but I don't know &quot;what to look for&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If MF is too high, would there be any chance to detect anything through their harmonics?&lt;/p&gt;&#xA;" OwnerUserId="6478" LastActivityDate="2016-08-25T06:54:08.977" Title="Detecting seismic waves using Software Defined Radio" Tags="|seismology|waves|seismic|seismic-hazards|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8595" PostTypeId="2" ParentId="8592" CreationDate="2016-08-21T04:19:57.247" Score="2" Body="&lt;p&gt;At thirty to thirty-eight degrees north and south of the equator are the so-called Horse Latitudes, regions with constant high-pressure systems. These regions inhibit precipitation. The phenomenon is quite well described and illustrated on Wikipedia:&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Horse_latitudes&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Horse_latitudes&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6480" LastActivityDate="2016-08-21T04:19:57.247" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8596" PostTypeId="1" AcceptedAnswerId="8597" CreationDate="2016-08-21T07:54:51.157" Score="-1" ViewCount="196" Body="&lt;p&gt;I was not sure just where to ask this question, but I was wondering if the sealed bottle garden be really called a perpetual motion machine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.dailymail.co.uk/sciencetech/article-2267504/The-sealed-bottle-garden-thriving-40-years-fresh-air-water.html&quot; rel=&quot;nofollow&quot;&gt;http://www.dailymail.co.uk/sciencetech/article-2267504/The-sealed-bottle-garden-thriving-40-years-fresh-air-water.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It has its own isolated ecosystem, and can be self sufficient for years with only needing to water once.&lt;/p&gt;&#xA;" OwnerUserId="6481" LastActivityDate="2016-08-21T13:30:10.617" Title="Can the sealed bottle garden be called a perpetual motion machine?" Tags="|geophysics|geodynamics|geobiology|" AnswerCount="2" CommentCount="3" ClosedDate="2016-08-21T19:34:39.767" ContentLicense="CC BY-SA 3.0" />
  <row Id="8597" PostTypeId="2" ParentId="8596" CreationDate="2016-08-21T09:20:02.823" Score="5" Body="&lt;p&gt;There are no perpetual motion machines.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So when you think you've found one, you need to ask a couple of questions, because there will always be an answer to at least one of them.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;How is the dissipation of energy being concealed? That is to say, some energy store is being depleted - where is it?&lt;/li&gt;&#xA;&lt;li&gt;Where is the additional energy coming from?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;In this case, additional energy is coming from the light that enters the sealed bottle garden. If there's no light, there's no growth.&lt;/p&gt;&#xA;" OwnerUserId="100" LastActivityDate="2016-08-21T09:20:02.823" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8598" PostTypeId="1" CreationDate="2016-08-21T11:19:45.970" Score="3" ViewCount="200" Body="&lt;p&gt;I am to deliver an informative speech about earthquakes in class. However, I was not the first to talk about earthquakes and his discussion of the cause of earthquakes is different from mine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;He mentions that there are multiple causes of earthquakes like a volcanic eruption, release of seismic waves, and tectonic plate movement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, from the information I gathered from the United States Geological Survey, it states that the cause is the movement of tectonic plates. The roughness of the plate boundaries cause them to get stuck; thereafter, when the plates move far enough, the boundaries unstick, releasing seismic waves, causing an earthquake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the movement of tectonic plates &lt;strong&gt;one of the causes&lt;/strong&gt; or the volcanic eruptions, etc. are the cause of the sudden slip or the part when the boundaries unstick which cause the earthquake?&lt;/p&gt;&#xA;" OwnerDisplayName="user6354" LastActivityDate="2016-08-21T13:20:07.487" Title="Are the other causes of an earthquake (e.g. volcanic eruptions) the cause of the &quot;sudden slip&quot; which is the main cause of an earthquake?" Tags="|volcanology|seismology|earthquakes|plate-tectonics|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8599" PostTypeId="2" ParentId="8598" CreationDate="2016-08-21T13:20:07.487" Score="2" Body="&lt;p&gt;When you look at a table of all the major historic earthquakes they are all related to plate tectonics, either directly or indirectly. These are all of the magnitude 7 to 9 events, and most of the magnitude 4 to 6 events. The linkage with volcanic eruptions is real, but weak. Again, most but not all, of the world's volcanoes are generated by plate tectonic processes, the main exceptions being intra-plate movement over mantle hot spots. As we get down to lesser magnitudes we are getting into greater frequencies. It is roughly a logarithmic relation ship, so for every major earthquake, there are thousands of low to medium level earthquakes and millions of small micro-seismic events - the latter being so small that nobody notices - except for geophysicists. There is a host of processes which give rise to low-level seismicity, such as submarine slope failures, turbidites, sedimentary compaction, thermal contraction, magma redistribution at depth, erosive load shedding, after-shock adjustments, landslides, mudslides, rock-falls, rapid draw-down in reservoirs, mining subsidence, fracking, and probably a load of other stuff that I can't think of right now. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So it's roughly a matter of scale. The USGS is correct that serious earthquakes are all caused by plate tectonics. On the other hand, your other source was right, that some seismicity can be caused in a multitude of ways. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Afterthought: Probably someone will point out very rare exceptions, such as major bolides crashing into Earth and causing shock waves right through the planet. But such are extremely abnormal.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-21T13:20:07.487" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8600" PostTypeId="2" ParentId="8596" CreationDate="2016-08-21T13:30:10.617" Score="0" Body="&lt;p&gt;I think this is off topic - its physics; basic thermodynamics, to be precise. But EnergyNumbers is correct. Whenever there is a claim to perpetual motion, always take as close look at the &lt;em&gt;total&lt;/em&gt; energy inventory, including infra-red, heat, light, UV, chemical, and radioactivity. Invariably, someone has either overlooked a component of the energy balance, or is not looking at a realistic time scale.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-21T13:30:10.617" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8609" PostTypeId="1" CreationDate="2016-08-22T17:41:58.233" Score="1" ViewCount="232" Body="&lt;p&gt;I am considering buying a house in a valley with pesticide-intensive agriculture on both sides. Schematically, it looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Bxwmn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Bxwmn.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It won't win any design awards, but it should make things clear. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is how the pesticide vapor drift would behave? Wouldn't there be a high risk that the cold air with the vapor gets trapped there?&lt;/p&gt;&#xA;" OwnerUserId="6487" LastActivityDate="2016-08-23T06:25:57.727" Title="How would pesticide vapor drift behave near a valley?" Tags="|pollution|air-pollution|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8610" PostTypeId="1" CreationDate="2016-08-22T21:29:44.393" Score="2" ViewCount="2064" Body="&lt;p&gt;I'm fairly inexperienced with WRF and was wondering if anyone could point me in the direction of any helpful resources for it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The task I have is to make a simple 9 km domain, but I'm having trouble understanding what some of the variables actually do/mean?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Specifically,  e_we/sn , dx/dy , and how a nested domain works.&lt;/p&gt;&#xA;" OwnerUserId="6488" LastEditorUserId="6488" LastEditDate="2016-08-22T22:18:13.460" LastActivityDate="2016-08-22T22:18:13.460" Title="How to set up a domain from namelist in WRF?" Tags="|models|numerical-modelling|wrf|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8611" PostTypeId="2" ParentId="8610" CreationDate="2016-08-22T21:55:19.360" Score="2" Body="&lt;p&gt;There is a WRF domain Wizard offered by ESRL. You can download it &lt;a href=&quot;http://esrl.noaa.gov/gsd/wrfportal/DomainWizard.html&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;. Also, don't make the same mistake I made using Lambert Conformal- keep stand_lon the same as your ref_lon.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2016-08-22T21:55:19.360" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8612" PostTypeId="2" ParentId="8609" CreationDate="2016-08-22T23:17:55.347" Score="1" Body="&lt;p&gt;First, check out the dominant pesticides being used. There are three main groups: organochlorides, which are relatively safe for people but bad for the environment (very long lasting); organophosphates, which are seriously toxic for people, but short-lived, so safe for the environment; and pyrethroids, which are pretty much safe for both humans and environment. If it is dominantly organophosphates then maybe you have cause for concern. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second, check out the proximity. Are they spraying right up to the walls of your house? If yes, then you may have a problem, but it is really only a potential problem within a few tens of metres of repeated exposure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Third check the weather. Obviously if the winds are blowing straight off the fields and into your kitchen, that is not a good scenario.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fourth, check out the disposal of pesticide containers. If there is a good waste disposal system for contaminated bottles, cartons, etc., and if farmers are reading the labels and sticking to the rules, then no problem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many people get very uptight about pesticides without understanding them. People do not fall ill from minute traces in groundwater and air. Farmers and their families get ill - generally from chemical violation of their central nervous system - when the farmer doesn't take appropriate precautions or follow the instructions. It is worrying when farmers in their fields walk into their own spray instead of spraying to the side, or when they mix up pesticides without gloves. No apron, no face-mask, careless discarding of pesticide containers into drainage ditches, etc. When the farmers wife washes the farmer's clothes - soaked in pesticide, then she's also at risk. Organophosphates in particular can be absorbed through the skin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is impossible to comment about wind drift without much more detailed local knowledge of conditions. My advice is don't get paranoid, but do use common sense about repeated exposure at high concentrations.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2016-08-22T23:40:55.450" LastActivityDate="2016-08-22T23:40:55.450" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8614" PostTypeId="1" CreationDate="2016-08-23T02:47:42.730" Score="1" ViewCount="225" Body="&lt;p&gt;I have come up with simulations which involves monte-carlo method that I am not fully aware of. I would be very happy if someone can help me with some references to read and learn. &lt;/p&gt;&#xA;" OwnerUserId="6491" LastActivityDate="2016-08-24T04:12:51.487" Title="What is meant by Monte-carlo simulation? (would like an elaborated answer with some references)" Tags="|geophysics|sedimentology|" AnswerCount="1" CommentCount="4" ClosedDate="2016-08-24T07:56:23.880" ContentLicense="CC BY-SA 3.0" />
  <row Id="8615" PostTypeId="2" ParentId="8609" CreationDate="2016-08-23T06:25:57.727" Score="3" Body="&lt;p&gt;While @Gordon Stanger gave an overall perspective about pesticides in general in his answer you can deduce some key points about the micrometeorological conditions of the area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming pesticides as relatively large aerosol particles/droplets spayed quite close to ground they are mainly dry deposited to surfaces. If your house is as close to the pesticide spaying areas as your schematic implies, you might have a problem (assuming pesticides are dangerous to you, more in @Gordon Stangers answer) only if during the spraying air gets trapped into the valley.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming the spraying is only done in daytime and summertime the chances of an inversion in the valley are smaller and they would only stabilize the air preventing mixing with your valley air and pesticide air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Strong winds (if the location is near a coast (probable sea breeze) or it's otherwise known to be windy) might carry some pesticides to your direction, but overall adding vertical mixing dramatically lowering the average concentrations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your most worst case scenario is if calm (not windy) very sunny days are very often. Sun will in different times of days heat at least either of the slopes of the valley causing air to rise on that side. Replacing air is sucked from the other side creating a steady flow from pesticide rich agricultural areas to your valley. Pesticide being assumed a large aerosol will deposit most likely in the valley (if not in the bottom then in the drafts uphill).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also rainy weather is good for you as the pesticides will most likely wet deposit near their source.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastActivityDate="2016-08-23T06:25:57.727" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8616" PostTypeId="1" AcceptedAnswerId="8617" CreationDate="2016-08-23T08:08:06.627" Score="0" ViewCount="708" Body="&lt;p&gt;Thanks to &lt;a href=&quot;https://www.youtube.com/watch?v=pxmHHoTPSKI&amp;amp;t=41&quot; rel=&quot;nofollow&quot;&gt;one minute of the Earth&lt;/a&gt; we know that beach sand mother rock, besides the quartz itself, is (or was?) made of olivine, amphibole and orthoclase. I wonder, what is the name of that rock and where do the 3 annihilated minerals go if only quartz is left?&lt;/p&gt;&#xA;" OwnerUserId="6272" LastEditorUserId="44" LastEditDate="2016-08-23T13:26:55.353" LastActivityDate="2016-08-23T13:26:55.353" Title="The rock that gives birth to quartz sand" Tags="|geology|rocks|minerals|hydrogeology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8617" PostTypeId="2" ParentId="8616" CreationDate="2016-08-23T08:53:59.770" Score="4" Body="&lt;p&gt;In only one minute of presentation there isn't time for detailed discussion, so one has to make broad generalizations which, on closer inspection, aren't quite true. It &lt;em&gt;is&lt;/em&gt; true that most sand is made of quartz, and that most of this quartz arises from weathered granitic rocks, of which the main minerals are quartz, orthoclase and plagioclase, usually with some mica, quite rarely some amphibole and almost never olivine. In the magma olivine and quartz react to make either amphiboles (if it is a very hydrous melt) or pyroxenes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is possible to find a sedimentary rock made of weathered out quartz and feldspar grains. Depending upon the original chemistry the feldspar could be potassium-rich (orthoclase) or sodium-calcium-rich (plagioclase). The resulting sedimentary rock is known as an arkose. Arkose is common in dry areas of eroding granite, such as the dryer parts of sub Saharan Africa. However, it is much more common for the weathering to involve wet erosion - thousands of cycles of rain and sun, hot and cold, in which case the feldspars mostly decompose to clay (many varieties and sub-species). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Olivine is much more characteristic of basic volcanic rocks, especially basalts, which do not weather to yield quartz grains. Another rock type in which olivine is a major component is peridotite. This weathers to yield goethite (a kind of ironstone) and serpentine. Occasionally, if the pyroxene to olivine ratio is sufficiently high, the weathering can yield quartz as a secondary by-product. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another feature of quartz: Over long periods and especially at high temperatures and/or high pressures, it is very slightly soluble. Not that you would notice. The sand isn't going to dissolve beneath your feet, but every litre of surface water contains a few milligrams of dissolved quartz as silicic acid, which takes part in a whole catalogue of geological processes. In addition, there are many other rocks besides granite which yield quartz grains, including quartzite, weathered pre-existing sandstone, schist, gneiss, and some intermediate rocks (complex chemistry between granite and basalt. Even limestone - rocks that are generally thought of as 'pure' calcium carbonate, generally have a percent or two of insoluble residue, of which quartz is the dominant component. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2016-08-23T10:29:27.020" LastActivityDate="2016-08-23T10:29:27.020" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8619" PostTypeId="1" CreationDate="2016-08-23T09:29:21.747" Score="5" ViewCount="1704" Body="&lt;p&gt;Identical drop in head in unconfined and confined aquifers releases different amounts of water. The confined aquifer releases less water and thus has less specific storage. When both aquifers are fully saturated then what makes storage in confined aquifer lower as compared to unconfined?&lt;/p&gt;&#xA;" OwnerUserId="5557" LastEditorUserId="4789" LastEditDate="2016-08-23T16:05:15.507" LastActivityDate="2016-08-23T16:05:15.507" Title="Why confined aquifers have low storage?" Tags="|hydrology|water|groundwater|hydrogeology|water-table|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8620" PostTypeId="2" ParentId="8619" CreationDate="2016-08-23T10:25:28.200" Score="1" Body="&lt;p&gt;In an unconfined aquifer the 'storage' is that fraction of the saturated void space that can be drained. In a confined aquifer, what you are effectively measuring is the compressibility of the aquifer - that is, the water released by depressurizing the aquifer per unit head. They are really two different things. &#xA;In an unconfined aquifer, the water that is drained comes from a narrow cone of depression. In a confined aquifer, although the numerical storativity is very much less, the cone of depression extends very much further because it is a general pressure release which propagates far into the aquifer, in all directions, so the yield can still be very high. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-23T10:25:28.200" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8621" PostTypeId="1" CreationDate="2016-08-23T15:42:12.803" Score="4" ViewCount="205" Body="&lt;p&gt;What is the difference in using Laplace equation (say only in 1D) to simulate water flow in a porous media with that of using diffusion equation for same purpose?&lt;/p&gt;&#xA;" OwnerUserId="5557" LastActivityDate="2016-08-24T03:42:21.943" Title="comparing use of Laplace equation with diffusion equation to simulate flow of fluid/water through porous media?" Tags="|hydrology|hydrogeology|fluid-dynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8623" PostTypeId="2" ParentId="8621" CreationDate="2016-08-24T03:42:21.943" Score="2" Body="&lt;p&gt;The Laplace equation, (d^2 Ψ)/(dx^2 )+(d^2 Ψ)/(dy^2 )+(d^2 Ψ)/(dz^2 )=0, is just a steady state 3D flow equation. It's a black box conservation of hydraulic potential. Diffusion doesn't come into it. The Diffusion equation (assuming homogeneous isotropic conditions) is (∂^2 Ψ)/(∂x^2)+(∂^2Ψ)/(∂y^2)+(∂^2 Ψ)/(∂z^2)= S_s/K  ∂h/∂t. This discretizes the time element, and is very much dependent upon the diffusive properties of the aquifer. Note that S_s/K is the reciprocal of the 'hydraulic diffusivity', hence the name of the equation.  &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-24T03:42:21.943" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8624" PostTypeId="2" ParentId="8614" CreationDate="2016-08-24T04:12:51.487" Score="0" Body="&lt;p&gt;There are times when any realistic 'answer' has to incorporate some degree of randomness. For example, when interpolating missing data in a rainfall time-series. You can do this 'informally', or through a slightly more rigorous 'Monte-Carlo' approach - there are several possible ways to deal with such problems. J.E. Gentle's book; &lt;em&gt;Random Number Generation and Monte Carlo Methods&lt;/em&gt;, is a good read, although being 2003, it's starting to look a bit dated. But it's more than enough to get you started, and then the rest you can do with off-the-shelf software. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alternatively, as Farrenthorpe points out, the Wikipedia reference may give you all you need to know.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-24T04:12:51.487" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8625" PostTypeId="2" ParentId="8594" CreationDate="2016-08-24T04:58:29.080" Score="3" Body="&lt;p&gt;I hope I understand your question right, I think there are some confusion about frequency range and wave-types. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seismic waves are acceleration of matter that transfer kinetic energy from a seismic source (e.g. an earthquake, an explosion or ambient noise) to heat. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's similar to sound waves, vibrations from the surface of e.g. a music instrument set the air in motion and compress the molecules of the air to transfer a wave that eventually reach e.g the eardrum. However, to add to the complexity, in solid matter some additional elastic properties are in play, as you notice. Waves can progress not only as pressure waves (P) but also as shear waves (S) and at boundaries special surface waves can form, often of high amplitude. The progression of the seismic waves depends on the elastic properties of the Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A large part of the terminology used for seismic waves are similar to how we describe electromagnetic waves. E.g. frequency, damping and resonance are relevant for seismic waves as well. However, the ranges are very different and electromagnetic waves and acoustic waves behaves different. The earth is a efficient filter, and even transient energy, that contains high frequencies, is limited to low frequencies as it progress through the Earth. Ground wave propagation, as know from radio signals, are different from the properties of seismic surface waves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An interesting coincidence is that wavelengths can be in the same magnitude, but that is because radio waves progress about 100.000 times faster than crustal seismic waves. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/se1oV.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/se1oV.gif&quot; alt=&quot;Charles J. Ammon Penn State University&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;A figure, prepared by Professor Charles J. Ammon, shows the ranges of frequency and amplitude. Source &lt;a href=&quot;http://eqseis.geosc.psu.edu/~cammon/HTML/Classes/IntroQuakes/Notes/seismometers.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. The amplitude and period have a large range, that's why prefixes as milli or micro can be used and a logarithmic scale is used for amplitude.&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In shallow active reflection seismic surveys, we sometimes can use frequencies up to maybe 200Hz, but in the range the penetration depth is very small. For very local events, e.g. in mines and infrastructure frequency range up to 500-1000Hz might be used. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most energy for P and S waves used in teleseismics are in the range of a few Hertz and maybe up to 10-20Hz. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Surface waves have the interesting property that the velocity depends on the frequency because low frequency content is affected by deeper elastic properties whiles high frequency content is more affected by shallow geological features. This is used for lithosphere tomography with rather good vertical resolution. The &lt;a href=&quot;http://www.seismo.com/msop/msop79/rec/fig_1.2.1b.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;frequency range&lt;/a&gt; is 0.005Hz and up to 0.5Hz. This is the frequencies that you can actually &lt;a href=&quot;http://www.bbc.com/news/world-asia-36061715&quot; rel=&quot;nofollow noreferrer&quot;&gt;see&lt;/a&gt; in ground motions caused by earthquakes, if you take resonance in consideration. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Normal_mode#Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Normal modes&lt;/a&gt; are often in the range 0.3 - 1mHz. (m, as in milli, not M, as in Mega). That is frequencies about one billiard times lower than some radio frequency bands.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another thing to remember in the context of Software defined radio, is that there is no carrier wave for seismicity. When seismologists talk about frequency, we mean energy content of a signal. We are looking at the convoluted wavelet, not continuous signals. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are interested in working with earthquake detection and to improve algorithms of signal processing of seismic waves, I'd suggest you to take a look at the &lt;a href=&quot;https://github.com/obspy/obspy/wiki&quot; rel=&quot;nofollow noreferrer&quot;&gt;Obspy&lt;/a&gt; package, there are some nice examples and tutorials that can get you started. There are also some project where people are constructing open architecture seismometers, eg the &lt;a href=&quot;https://www.raspberrypi.org/blog/raspberry-shake-personal-seismograph/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Raspberry Shake&lt;/a&gt;. For less than $100 or so you can build a seismograph and start to monitor local seismic events. Most geophones work by transfering ground acceleration to an induced electric current in a coil. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's very possible that inspiration from other fields of signal processing, as in &lt;a href=&quot;https://en.wikipedia.org/wiki/Software-defined_radio&quot; rel=&quot;nofollow noreferrer&quot;&gt;Software defined radio&lt;/a&gt; can improve seismic techniques in future. It is always great to get inspiration from other fields of research. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2016-08-25T06:54:08.977" LastActivityDate="2016-08-25T06:54:08.977" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8626" PostTypeId="2" ParentId="7119" CreationDate="2016-08-24T11:51:31.677" Score="4" Body="&lt;p&gt;As you say in your question, ball lightening and and St Elmo's Fire are related to thunderstorm activity (e.g., Griwr'ev et al, 1991). Grigor’ev et al (1999) worked out a formula for the charge on small drops of water (which is a bit complicated for a simple answer), but suffice to say the total voltage involved  is high when you scale from one drop to millions. For example ~30kV per cubic centimetre is in the literature for initiating Ball Lightening, and lower for St Elmo's Fire because the coronal discharge nucleates on pointed or sharp objects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you troll physics forums about demonstrating St Elmo's fire in a laboratory setting, you'll see that it is actually quite dangerous, due to the high voltage. Most suggestions by physics teachers are to demonstrate the effect in neon gas, rather than air, and within glass bulbs. So one answer to your question is that the effect can be dangerous, e.g., when creating conditions of coronal discharge in an experimental setting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What about in a natural setting? You can read in Griwr'ev et. al (1991) about several hundred reports of St Elmo's Fire sightings, but it isn't mentioned whether anyone has been 'within' the effect. However, St Elmo's Fire was observed on the Hindenburg shortly before it exploded (Robinson, 1964); not that this was the likely 'spark' that caused the explosion, but part of the prelude. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can't find any verified reports of people immersed in St Elmo's Fire during my quick review of published literature, or non-peer reviewed sources like Scientific American and Wikipedia. There is an interesting reference in Wikipedia to Tesla managing to light up some butterflies with one of his coils, though!&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Griwr'ev, A. I., I. D. Griwr'eva, and S. Shiryaeva. &quot;Ball lightning and St. Elmo's fire as forms of thunderstorm activity.&quot; (1991)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Grigor’ev, A. I., and S. O. Shiryaeva. &quot;Critical conditions for instability of a highly charged oblate spheroidal drop.&quot; Technical Physics 44.7 (1999): 745-749.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Robinson, Douglas. LZ-129 Hindenburg. New York: Arco Publishing Co, 1964.&lt;/p&gt;&#xA;" OwnerUserId="6480" LastActivityDate="2016-08-24T11:51:31.677" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8627" PostTypeId="1" CreationDate="2016-08-24T13:29:45.763" Score="6" ViewCount="86" Body="&lt;p&gt;The Swedish meteorological agency SMHI on &lt;a href=&quot;http://www.smhi.se&quot; rel=&quot;noreferrer&quot;&gt;its website&lt;/a&gt; (&lt;em&gt;NB: freezes Firefox on Linux for me, likely due to plugins, works in Chrome&lt;/em&gt;) indicates how certain the forecast for a particular day is.  Looking at &lt;a href=&quot;http://www.smhi.se/vadret/smhi-lab/sannolikheter-beta#ws=wpt-a,proxy=wpt-a,geonameid=2698281&quot; rel=&quot;noreferrer&quot;&gt;today (Wednesdays) forecast for the coming week for Kvikkjokk&lt;/a&gt;, they estimate that the forecast for Friday is &lt;em&gt;ganska säker&lt;/em&gt; (somewhat certain), for Saturday is &lt;em&gt;osäker&lt;/em&gt; (uncertain), and for Sunday is &lt;em&gt;säker&lt;/em&gt; (certain); they estimate that the forecast for Sunday is &lt;em&gt;more&lt;/em&gt; certain than the forecast for either Friday or Saturday.  I suppose that what they do is look at the forecast ensemble and estimate certainty based on agreement between different runs from the ensemble.  But as the state of the atmosphere on Sunday should depend on the state on Friday and Saturday, is there any way how it can make sense that the forecast for Sunday is more certain than the one for Friday or Saturday?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PVMGG.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PVMGG.png&quot; alt=&quot;Odd certainty estimate in forecast&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="192" LastEditDate="2016-08-24T21:14:35.663" LastActivityDate="2016-08-24T21:14:35.663" Title="Can the forecast N+1 days ahead be more certain than the forecast N days ahead?" Tags="|meteorology|weather-forecasting|predictability|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8628" PostTypeId="1" AcceptedAnswerId="8632" CreationDate="2016-08-24T15:08:29.757" Score="2" ViewCount="83" Body="&lt;p&gt;We searched for cinnabarit in an abandoned mine (&lt;a href=&quot;https://goo.gl/maps/gbyt4h6YdZ42&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google Maps&lt;/a&gt;, in Békásmegyer, Hungary). We collected these samples, but as we are not geologists, we are not sure what we found. Pictures about the samples:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/O1djK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/O1djK.jpg&quot; alt=&quot;picture 1&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Hp1DS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Hp1DS.jpg&quot; alt=&quot;picture 2&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Did we succeed, is this indeed cinnabarit?&lt;/p&gt;&#xA;" OwnerUserId="6500" LastEditorUserId="725" LastEditDate="2016-08-24T23:04:32.373" LastActivityDate="2016-08-24T23:04:32.373" Title="Did we find cinnabarit?" Tags="|geology|mineralogy|minerals|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8629" PostTypeId="1" CreationDate="2016-08-24T17:32:28.607" Score="-7" ViewCount="265" Body="&lt;p&gt;Specifically, if the daily production of ozone and cfc were at most 400 million and 3k tons, respectively, would each mol of cfc be able to destroy tens of thousands of mols of ozone? All the sources I can find show cfc being much less potent than that.&lt;/p&gt;&#xA;" OwnerUserId="6062" LastEditorUserId="6062" LastEditDate="2016-08-25T12:58:24.080" LastActivityDate="2016-08-27T05:47:37.490" Title="What is the science behind CFCs depleting the ozone layer?" Tags="|atmosphere|" AnswerCount="1" CommentCount="3" ClosedDate="2016-08-27T15:26:46.337" ContentLicense="CC BY-SA 3.0" />
  <row Id="8630" PostTypeId="1" CreationDate="2016-08-24T19:09:27.737" Score="7" ViewCount="1458" Body="&lt;p&gt;Looking at continental plates both France and GB lie on the Earasian plate. Now those plates moves and created our continents of today out of Pangea. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But a lot of pictures shows that France and GB were once stuck together. Also their shapes looks like they fit together. &lt;br /&gt;&#xA;But if they lie on the same plate how is it possible that those contries are now separated? Is it possible that the oceans eroded land between them so they became separate?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or is it possible that in one plate there were plenty of little continental drifts too; if that is true what is the difference between a continental drift and drift within plates. Or is it even possible that GB lies on its own plate?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AR0e0.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AR0e0.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br /&gt;&#xA;Picture taken from the hi-res drawing at &lt;a href=&quot;http://io9.gizmodo.com/heres-what-pangea-looks-like-mapped-with-modern-politi-509812695&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's what Pangea looks like mapped with modern political borders&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="595" LastEditDate="2016-08-29T09:15:47.033" LastActivityDate="2016-09-05T22:08:07.530" Title="How did Great-Britain separate from France?" Tags="|geophysics|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8631" PostTypeId="2" ParentId="8627" CreationDate="2016-08-24T20:35:08.183" Score="8" Body="&lt;p&gt;Typically, days with conditions which might produce local instabilities would produce a less certain forecast than a day with a stabilize pattern even if the more stable day was further in the future.  For instance, tomorrow may have the potential for localized disturbances some maybe there will be thunderstorms, maybe they will not form.  But two days later, a large high pressure zone will almost certainly clear everything out or a band of rain will definitely reach the area.&lt;/p&gt;&#xA;" OwnerUserId="6178" LastActivityDate="2016-08-24T20:35:08.183" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8632" PostTypeId="2" ParentId="8628" CreationDate="2016-08-24T20:36:41.173" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Did we succeed, is this indeed cinnabarit?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Probably yes. Cinnabar has a very distinct brick-red colour, and some of your samples definitely have it. I'm not certain how much of this is actually cinnabar and how much is other stuff, but there is enough cinnabar in there to make it obvious just from the picture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;IMPORTANT&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cinnabar is toxic. It will release mercury metal on oxidation (that is, exposure to air), on exposure to water (so don't throw it in the river), and on exposure to strong light (that is, sunlight). On heating it will release mercury vapour. &lt;strong&gt;People die because of this.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Go to the mine, and put it back in there, never taking it back. In case you do want to keep one of them, make sure it is clearly labelled as TOXIC and DANGEROUS and POISON in both English and Hungarian, and keep it away from children and pets.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-08-24T20:36:41.173" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8633" PostTypeId="2" ParentId="8630" CreationDate="2016-08-25T00:46:18.890" Score="8" Body="&lt;p&gt;&quot;Is it possible that the oceans eroded land between them so they became separated&quot;? Yes, sort of, but it isn't a simple story. There are several factors: (1) Rivers eroded much of the English channel, mostly during the last ice age when sea level was up to 120 metres below the present level. The Rhine actually flowed (and eroded) much further out into what is now the English channel. (2) Some have argued - though I'm not sure that I agree with them - that at least part of the English Channel was cut by glaciers. However, the main British ice sheet was further north than the channel. (3) There is sound evidence that an ice dam collapsed, resulting in a huge glacial lake outburst, which would certainly have resulted in major erosion. (4) The Alpine orogeny of late Mesozoic / early Cenozoic age, created a compressive zone across much of northern Europe, thereby flexing low-angle folding. One of the major folds was the Wealden anticline, most of which is exposed in southern England, but to a lesser extent also in northern France. Tension fractures in this anticline created an area of weakness and enhanced erosion across what is now the eastern English Channel. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could microplate tectonics have contributed? Good question. Certainly it is possible for the jostling of major plates to splinter off microplates, or even mesoplates - examples being the Aegean region, and the rotation of Iberia, respectively. I don't have any information on the deep geology of the Western English channel, but I suspect that tectonic thinning of the crust in that area may have contributed to subsidence and subsequent flooding.  &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-25T00:46:18.890" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8635" PostTypeId="2" ParentId="8629" CreationDate="2016-08-25T13:37:52.890" Score="3" Body="&lt;p&gt;I guess nobody has given DJ Sims the simple answer he/she wants because such a generalized question is indeterminate. The chlorine is relatively stable, so 'how many ozone mols are destroyed' depends upon the availability of relatively short-lived ozone. In a dry atmosphere this is very much a function of temperature. At -50 deg C ozone's half life is about 3 months, but at 0 deg C it is only about 5 days. It also depends upon humidity, pH and a swag of associated high-atmospheric reactions. The ozone availability is also a function of ozone's regeneration rate. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2016-08-27T05:47:37.490" LastActivityDate="2016-08-27T05:47:37.490" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8636" PostTypeId="1" AcceptedAnswerId="8646" CreationDate="2016-08-25T19:29:49.500" Score="2" ViewCount="278" Body="&lt;p&gt;Or, in other words, what kind of data can be gathered from inside tornadoes and how could it help in predicting them? Also, why isn't it possible to predict/estimate this kind of data from readings taken from outside the funnel (or is that what is currently done)?&lt;/p&gt;&#xA;" OwnerUserId="6506" LastActivityDate="2016-08-27T18:20:44.477" Title="Why is it so important to gather data from inside tornadoes?" Tags="|meteorology|severe-weather|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8637" PostTypeId="1" AcceptedAnswerId="8722" CreationDate="2016-08-25T19:43:42.457" Score="6" ViewCount="604" Body="&lt;p&gt;I have lightning data that contains individual strikes and their location, time, polarity, amplitude and type (cloud-to-ground, intracloud). I am trying to develop some metrics that will help me assess if a thunderstorm is intense or not. By intense, I mean if it has the potential to generate heavy rain, large hail and strong winds. I plan on using radar reflectivity as my best guess of storm intensity and building a statistical model between the two datasets.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By browsing through the litterature, it seems that a sharp increase in positive cloud-to-ground lightning frequency is a sign of storm intensification to come. I was wondering if there was anything else that I could work with. Is amplitude useful in any way? Is the ratio of IC to CG lightning relevant? Is there another metric I could develop?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;" OwnerUserId="6444" LastEditorUserId="6444" LastEditDate="2016-08-26T12:13:10.587" LastActivityDate="2016-09-12T02:27:43.260" Title="How are lightning and thunderstorm intensity linked?" Tags="|meteorology|lightning|severe-weather|thunderstorm|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8638" PostTypeId="2" ParentId="8569" CreationDate="2016-08-25T23:09:35.397" Score="2" Body="&lt;p&gt;Adding an answer here just to note that the usual practice that aretxabaleta explains is not universal. It turned out for me that the software I was using counted from the start of the Dublin Julian Day epoch (1200h, Dec 31, 1899). So I guess it varies a bit.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2016-08-25T23:09:35.397" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8639" PostTypeId="1" CreationDate="2016-08-26T06:11:00.433" Score="-2" ViewCount="1130" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/imL3f.jpg&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Gkshl.png&quot; alt=&quot;&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It looks like global warming doesn't work. Can anyone refute this?&lt;/p&gt;&#xA;" OwnerUserId="6062" LastEditorUserId="6062" LastEditDate="2016-08-26T19:20:34.207" LastActivityDate="2016-08-27T19:33:21.520" Title="Is global warming nonsense?" Tags="|climate|" AnswerCount="1" CommentCount="8" ClosedDate="2017-04-13T08:21:07.287" ContentLicense="CC BY-SA 3.0" />
  <row Id="8640" PostTypeId="2" ParentId="8639" CreationDate="2016-08-26T08:15:27.620" Score="16" Body="&lt;p&gt;No, global warming is not nonsense, and if you are suspicious of the above 'graph' then you are acting wisely. &#xA;Climate deniers, like flat Earthers, Biblical literalists and many more, use pseudo-science, 'sleight of hand' and cherry picking of data to give false, but superficially plausible impressions. The above is a case in point. Their starting half-truth is that there have been many climatic fluctuations in the past. Yes, but where is the vertical scale, and indeed where did this curve come from? You won't see it in any reputable data-set. Harris &amp;amp; Mann argue on a time-scale of about 5000 years. Let us broaden that to the reliable published data for the last 400,000 years in Petit et al (1999) Nature vol 399. Notice firstly how close a match the temperature is to the atmospheric CO2 concentration. Notice secondly how the CO2 concentration never exceeds 300 ppm in the prehistoric record. Thirdly, note that the current CO2 concentration now exceeds 400 ppm, and continues to rise fast. Check out &lt;a href=&quot;http://www.esrl.noaa.gov/gmd/ccgg/trends/&quot; rel=&quot;noreferrer&quot;&gt;Trends in Atmospheric Carbon Dioxide&lt;/a&gt;. Fourthly if you examine the data from about 1900 onwards, you will note that the average annual temperature correlates closely to the mean annual CO2. If, instead of the atmospheric temperature mean, you consider the global heat increase (mostly in the ocean) then you will find an even better correlation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0P4jp.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0P4jp.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One could go on at great length about individual country climatic records, a better than 98.5% scientific consensus, satellite verification, rates of glacial retreat, increasing rates of sea level rise, and so on - but what's the point. To conspiracy theorists who have made up their mind - and don't want to be confused by the facts, no amount of evidence will change their views. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Harris and Mann claim to be 'world class climatologists'. Well, check out Google Academic Advanced search, and see if you can find any of their papers. Sure, variations of the above hokum can be found, but not in any respectable peer reviewed journal. It's all in some obscure publishing house, seemingly of their own making, with links to Christian fundamentalist and conspiracy theory web pages. So should you pay any attention to such views? Maybe, if you must, but first hone your critical faculties to discern the difference between real science and junk science. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="6093" LastEditDate="2016-08-27T19:33:21.520" LastActivityDate="2016-08-27T19:33:21.520" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8641" PostTypeId="2" ParentId="2158" CreationDate="2016-08-26T18:15:31.913" Score="1" Body="&lt;p&gt;If you know your current position, and the position of the land youʻre headed toward, then you only need to be able to determine direction and keep track of your progress (perform dead reckoning).  You can determine direction from some key stars (the sun rises and sets near east and west, and the exact direction depends on the time of year).  The North star is always north, and Mintaka in Orionʻs belt rises due east and sets due west from every latitude on Earth.  Other starsʻ rising and setting points depend on your latitude to varying degrees.  You can roughly check your latitude by the height of Polaris, the North Star, above the northern horizon, or by the height of the upright Southern Cross above the southern horizon.  There are also certain pairs of stars that point very nearly due north or due south when they are stacked vertically.  For example, Dubhe and Merak when aligned vertically are nearly directly above due north.  They also act as a guide to locating the north star.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you donʻt know your position, or the position to land, then you need some kind of indicator from the land itself.  In the trade wind belts, there is often a stationary pile of clouds over high volcanic islands, whereas most cumulus clouds float freely downwind.  It is alleged that clouds directly over coral atolls with central lagoons may sometimes reflect a green color from the lagoon.  Seabirds such as the brown noddy and fairy tern that are known to sleep on land at night can be used to locate land, since they head out to sea in the morning to fish and fly back at night to sleep.  That gets more complex when they make multiple fishing trips to feed their young.  Lines of rubbish and organic matter (leaves, sticks) may indicate land is nearby.  If you know the prevailing direction of the swells or can calibrate them with the rising or setting sun or recognizable star, swell directions typically donʻt change quickly in under 24 hours.  If there are multiple swell patterns with the exact same period (time between swells), that may indicate that one of the swells is a reflection off of an island of the other swell, or a refraction of the original swell bent by the shallow water around an island.  This was a mainly Marshallese island technique.  They were noted for their wave pattern stick charts, which were apparently more used for studying and teaching than actual use during a voyage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/We,_the_Navigators&quot; rel=&quot;nofollow noreferrer&quot;&gt;We, The Navigators&lt;/a&gt; by David Lewis chronicles much of this.&lt;/p&gt;&#xA;" OwnerUserId="6508" LastEditorDisplayName="user1161" LastEditDate="2017-03-29T13:20:00.717" LastActivityDate="2017-03-29T13:20:00.717" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8642" PostTypeId="1" CreationDate="2016-08-27T00:26:00.093" Score="3" ViewCount="419" Body="&lt;p&gt;For some reason today, carbonated beverages have been fizzing up more than usual. It's happening with beer and club soda. Very strange, no gremlins either - the beer was from the back of the fridge, been there since yesterday. The club soda was still for plenty of time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was thinking low atmospheric pressure could be at hand. There are stratocumulus clouds in the sky, the AC is on. In Chicagoland area.&lt;/p&gt;&#xA;" OwnerUserId="6513" LastActivityDate="2016-09-26T02:32:08.003" Title="Can atmospheric conditions cause carbonated beverages to fizz more?" Tags="|atmosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8643" PostTypeId="2" ParentId="8642" CreationDate="2016-08-27T01:45:25.560" Score="2" Body="&lt;p&gt;This is physics rather than Earth Sciences, but differential pressure between tinned liquid and atmosphere is by far the dominant factor. In Scotland I remember opening a can of 7-up at sea level with almost no effervescence. Then I climbed Ben Nevis, 1344 metres, and celebrated reaching the summit with another can. The resulting 'geysir' ejected about half the can in spectacular fashion. Temperature also has an effect in that the solubility of CO2 on a cold day, say 10 deg C, is about 30% more than on a hot day of ~30 deg C. So if the outside temperature is warmer than at the time the drink was canned, then there will be an excess of free gas that has come out of solution, but is still in the can waiting to be released. If we say two grams of excess CO2 in the can, that will yield about a litre of gas at one atmosphere and 21 deg C. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm wondering what the effect of a high sugar content would be. Could large organic molecules act as foci for gas bubble formation? Maybe a fun  school experiment!&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-27T01:45:25.560" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8644" PostTypeId="1" AcceptedAnswerId="8645" CreationDate="2016-08-27T11:23:57.903" Score="2" ViewCount="546" Body="&lt;p&gt;In most illustrations and diagrams of the types of faults, there is always something similar. I noticed that there is a side of the hanging wall and foot wall which is slanted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jQetZ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jQetZ.png&quot; alt=&quot;Fault representations&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We're supposed to make a models for each type of fault; however, the material to be used will be difficult to cut diagonally. I'd like to know if it is necessary to have one side slanted? Or if having it vertical fine. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please mention sources too. Thank you.&lt;/p&gt;&#xA;" OwnerDisplayName="user6354" LastActivityDate="2016-08-27T15:28:49.233" Title="Fault representation" Tags="|seismology|earthquakes|plate-tectonics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8645" PostTypeId="2" ParentId="8644" CreationDate="2016-08-27T15:07:56.803" Score="1" Body="&lt;p&gt;&lt;a href=&quot;http://geomaps.wr.usgs.gov/parks/deform/gfaults.html&quot; rel=&quot;nofollow&quot;&gt;Faults&lt;/a&gt; are results of stress. The direction of the stress controls what kind of fault that is formed. The most fundamental reason for a fault to occur is horizontal compression or extension, even if it's often more complicated in reality. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your two examples are dip-slip faults, with a vertical displacement as a result of horizontal stress. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In your first example, the &lt;a href=&quot;https://www.youtube.com/watch?v=tJDnfT1pqhQ&quot; rel=&quot;nofollow&quot;&gt;normal fault&lt;/a&gt;. The total distance (from left to right) is increased. There has been an extension of the crust. If the fault plane would have been vertical, no distance would have been gained. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the second example, the &lt;a href=&quot;https://www.youtube.com/watch?v=nV9XH7jCizA&quot; rel=&quot;nofollow&quot;&gt;reverse fault&lt;/a&gt;, the distance is decreased. It's been a horizontal compression of the crust. The dip of a reverse fault is usually rather steep. If the dip is lower, you'll rather form a ramp. Typical for thrust faults. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Vertical fault planes are associated with strike-slip faults or ring faults above collapsing calderas or sinkholes. It's also common, but not for textbook examples of dip-slip faults. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, unless you are showing a strike-slip fault, you have to find a way to cut diagonally. Do measure the horizontal displacement! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Addition about making fault models: &#xA;We made a layer cake for a college some time ago and (of course) wanted to have a fault in it. The simplest way was to make a reverse fault, erode the uppermost layer of the hanging wall block and assume that the lowest exposed layer was of the same lithology (chocolate sandstone reservoir rock). However, it took some geoenginering to make it look good and we decided to make an impact crater next time.&lt;/em&gt; &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2016-08-27T15:28:49.233" LastActivityDate="2016-08-27T15:28:49.233" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8646" PostTypeId="2" ParentId="8636" CreationDate="2016-08-27T18:20:44.477" Score="1" Body="&lt;p&gt;Generally speaking, the types of data gathered outside a tornado can also be measured inside the tornado. Currently, forecasters try to estimate an area where tornadoes usually are. The forecasting time for tornadoes, or warn time, is about &lt;a href=&quot;http://www.theatlantic.com/technology/archive/2014/04/13-minutes-thats-the-average-warning-time-before-a-tornado-strikes/361195/&quot; rel=&quot;nofollow&quot;&gt;13 minutes&lt;/a&gt;. There is still quite a bit we don't know about tornadoes, such as why some storms that look like they can produce a tornado, will not produce a tornado.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Currently, most data taken about tornadoes is taken outside of the tornado. Data from inside the tornado, while uncommon, can give improved estimates of wind speeds, and pressure changes, with a level of detail that is hard to get from the outside, looking in. The models we deal with are imperfect- there are too many sources of error and It generally doesn't help the current predictions, but research on that data may help future predictions.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2016-08-27T18:20:44.477" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8647" PostTypeId="2" ParentId="8482" CreationDate="2016-08-28T02:24:44.187" Score="2" Body="&lt;p&gt;To add to Centaurus's answer, the climate of both cities is strongly influenced by the local sea surface temperatures. Dalian monthly temperatures vary from about -7 to 27 deg C, whereas Vladivostok, less than 500 kilometres further north, varies from -15 to 23 deg C. So the temperature contrast is mainly in winter. During the December-March winter period prevailing cold dry winds from polar areas blow south from Sakhalin Island. There are two consequences, firstly it generates a strong counter-clockwise cold sea current which hugs the eastern coast of Russia. Secondly, there is massive evaporative cooling of the shallow warm surface waters, again, concentrated in winter. This accounts for the cold extremes of Vladivostok (as well as winter snows in Japan).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Dalian is 'warmed' by an offshoot of the Kuroshio current. 'Warmed' being a relative term, since the sea still approaches freezing point in late winter, but it is still warmer than the current near Vladivostok. Also, the Yellow Sea is one of the world's largest areas of continental shelf. That is, relatively shallow, so it warms up more during the summer, and has thermal inertial carry-over into winter. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-28T02:24:44.187" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8648" PostTypeId="1" CreationDate="2016-08-28T04:54:39.683" Score="3" ViewCount="1762" Body="&lt;p&gt;I would like to know what would be the impacts/effects on the tides if earth were to have no tilt (perpendicular to plane of ecliptic)? &lt;/p&gt;&#xA;" OwnerUserId="6517" LastEditorUserId="111" LastEditDate="2016-08-29T15:57:09.800" LastActivityDate="2018-02-05T14:01:15.160" Title="What would be the impact on tides if the earth had no tilt?" Tags="|ocean|earth-rotation|tides|axial-obliquity|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8650" PostTypeId="1" CreationDate="2016-08-28T17:14:55.370" Score="5" ViewCount="1447" Body="&lt;p&gt;&lt;strong&gt;What I am in search of is an open source tool to pick first arrivals, plot travel-time curves, and perform simple velocity modeling.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am experimenting with seismic refraction to identify shallow subsurface interfaces. This includes the water table in a sand channel and the sand/bedrock contact. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have a 24 channel Seistronix RAS-24 for field acquisition. This includes a field computer with software to set geometry, run the survey, and record data to various .seg formats. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I do not have is a reliable program to process and model my data. Thus far I have been evaluating seismograms in the field and calculating depths by hand with the text book equations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am open to any freely available software solution that would allow me to interpret and visualize my field data. This includes python or matlab based packages. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Are there any open source and community supported seismic refraction processing tools available?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="5657" LastEditorUserId="28050" LastEditDate="2018-04-05T00:23:44.043" LastActivityDate="2018-04-05T00:23:44.043" Title="Open source seismic refraction processing" Tags="|geology|geophysics|seismic|software|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8651" PostTypeId="1" AcceptedAnswerId="8652" CreationDate="2016-08-29T00:17:54.600" Score="4" ViewCount="200" Body="&lt;p&gt;Could someone please explain what reciprocal space means in the context of of x-ray diffraction of a crystal lattice?&lt;/p&gt;&#xA;" OwnerUserId="6522" LastActivityDate="2016-08-29T08:21:32.757" Title="Reciprocal space in the context of x-ray diffraction and a crystal lattice?" Tags="|crystallography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8652" PostTypeId="2" ParentId="8651" CreationDate="2016-08-29T01:56:17.063" Score="3" Body="&lt;p&gt;The unit cell space and reciprocal space are fourier transforms of each other. The unit cell indicates the stacking space between crystal elements. The reciprocal space is a similar kind of vectorial representation of the diffracted X-rays. The following reference explains it quite well, although it is not a simple concept. Unless you are smarter than me, you may have to read it 2 or 3 times to 'get it'. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://bama.ua.edu/~mweaver/courses/MTE583/MTE%20583_Class_17a.pdf&quot; rel=&quot;nofollow&quot;&gt;Reciprocal Lattices and Diffraction&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="6093" LastEditDate="2016-08-29T08:21:32.757" LastActivityDate="2016-08-29T08:21:32.757" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8653" PostTypeId="1" CreationDate="2016-08-29T07:24:24.023" Score="3" ViewCount="25" Body="&lt;p&gt;Does the level/reading/measurement of solar exposure impact temperatures? What I mean by this is, does a higher level/reading/measurement of solar exposure of a place cause/create higher temperatures, and does a lower level/reading/measurement of solar exposure of a place cause/create lower temperatures?&lt;/p&gt;&#xA;" OwnerUserId="6517" LastEditorUserId="6" LastEditDate="2017-03-31T13:06:13.917" LastActivityDate="2017-03-31T13:06:13.917" Title="Does the level/reading/measurement of solar exposure impact temperatures" Tags="|temperature|measurements|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8654" PostTypeId="2" ParentId="8587" CreationDate="2016-08-29T08:04:59.983" Score="3" Body="&lt;p&gt;There are micro-tectites galore, strewn over thousands of square kilometres. But remains of the actual bolide? Hard to say, because the impact crater is now buried under 600 metres of sediment. Earlier this year the joint IODP-ICDP drilling program drilled to a depth of 1300 metres. As far as I know, their findings are not published yet. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-29T08:04:59.983" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8655" PostTypeId="2" ParentId="8630" CreationDate="2016-08-29T08:29:00.543" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is it possible that the oceans eroded land between them so they became separated?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes and no, but it was mostly fresh water rather than the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is now the Dover Strait was solid high land until ~425,000 years ago (or perhaps ~200,000 years ago, or perhaps both). That time marked the end of the most extreme glaciation of the last 2.5 million years. Before then, Great Britain was a European peninsula rather than islands off of Europe, connected to Europe by the South Downs, North Downs, and lowlands further to the north.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Anglian_stage&quot; rel=&quot;nofollow&quot;&gt;Anglian glaciation&lt;/a&gt; (Marine Isotope Stage 12) was the most severe glaciation of the last 2+ million years. All of Scotland and most of England were covered with ice at that time. The ice to the north and the downs to the south initially prevented the glacial meltwaters from escaping to the ocean when that ice started melting at the end of this stage. The meltwaters formed a huge glacial lake that eventually overtopped the downs. The resulting catastrophic outburst flood carved deep channels in the chalk. This &lt;a href=&quot;https://en.wikipedia.org/wiki/Glacial_lake_outburst_flood&quot; rel=&quot;nofollow&quot;&gt;outburst flood&lt;/a&gt; marked the formation of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Channel_River&quot; rel=&quot;nofollow&quot;&gt;Channel River&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While the above explains the formation of the Dover Strait, it does not explain how the lowlands to the north of the Dover Strait became separated from continental Europe. Those lowlands have long formed a natural land bridge between continental Europe and the United Kingdom. The North Sea proper did not connect with the English Channel until rather recently. Humans, along with our ancestors, have crossed and lived on those lowlands for a long, long time. For example, &lt;a href=&quot;https://en.wikipedia.org/wiki/Happisburgh_footprints&quot; rel=&quot;nofollow&quot;&gt;hominid footprints from almost a million years ago&lt;/a&gt; (in other words, before &lt;em&gt;homo sapiens&lt;/em&gt;) have been found on the northern shores of England. Peoples regularly crossed this low-lying land which is now called &lt;a href=&quot;https://en.wikipedia.org/wiki/Doggerland&quot; rel=&quot;nofollow&quot;&gt;Doggerland&lt;/a&gt;. Rising sea levels following the most recent glaciation spelled the start of the end of Doggerland.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What most likely did Doggerland in were &lt;a href=&quot;https://en.wikipedia.org/wiki/Storegga_Slide&quot; rel=&quot;nofollow&quot;&gt;the Storegga Slides&lt;/a&gt; that occurred ~8300 years ago. Those underwater landslides created huge tsunamis. Traces of those tsunamis are found 80 km inland on the Firth of Forth. The damage to Doggerland would have been immense.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;References:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0088329&quot; rel=&quot;nofollow&quot;&gt;Nick Ashton, et al., &quot;Hominin footprints from early Pleistocene deposits at Happisburgh, UK.&quot; &lt;em&gt;PloS One&lt;/em&gt; 9.2 (2014): e88329.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3990419&quot; rel=&quot;nofollow&quot;&gt;Claire L. Mellett, et al., &quot;Denudation of the continental shelf between Britain and France at the glacial–interglacial timescale&quot;, &lt;em&gt;Geomorphology&lt;/em&gt; 203 (2013): 79-96.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://profmarkcollard.com/wp-content/uploads/2014/09/Weninger_et_al_2008.pdf&quot; rel=&quot;nofollow&quot;&gt;Bernhard Weninger, et al., &quot;The catastrophic final flooding of Doggerland by the Storegga Slide tsunami&quot;, &lt;em&gt;Documenta Praehistorica&lt;/em&gt; 35.15 (2008): 1-24.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="39" LastEditDate="2016-09-05T22:08:07.530" LastActivityDate="2016-09-05T22:08:07.530" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8656" PostTypeId="1" CreationDate="2016-08-29T08:39:14.760" Score="2" ViewCount="75" Body="&lt;p&gt;Merra re-analysis ara available for  a coarser horizontal grid with resolution of 0.625 × 0.5 degrees providing differents parameters : Precipitation, Temperature ....This been said, I want to interpolate continuously theses parameters ( More precisely : For each coordinate I want to know elevation, Precipitation , and other parameters ( Look the following example ).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Time step  // Latitude // Longitude // Elevation // Precipitation  ...&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1    ................ 30    .............     -7     ..................   1500 ...................       x             x    x ....x &lt;/p&gt;&#xA;&#xA;&lt;p&gt;1       ...............          30.25   .........     -7   ...................     x x ..........................x&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1  .................             31.11  .....      -6.63    ...................xx.......................X&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have an idea how to interpolate these data I would be grateful.&lt;/p&gt;&#xA;" OwnerUserId="6364" LastActivityDate="2017-06-22T20:15:55.557" Title="Interpolating Merra reanalysis" Tags="|atmosphere|atmosphere-modelling|climate-models|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8658" PostTypeId="2" ParentId="8648" CreationDate="2016-08-29T09:33:22.677" Score="2" Body="&lt;p&gt;I cannot answer your hypothetical question, but the tilt does probably affect the tides and there have been some studies on the topic. Hopefully they can inspire to further ideas and speculations. It appears that the main outcome from the report should be for you to understand how the moon, the Sun and the Earth control the tide and how the &lt;a href=&quot;https://en.wikipedia.org/wiki/Tidal_force&quot; rel=&quot;nofollow noreferrer&quot;&gt;tidal force&lt;/a&gt; works. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NiwZD.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NiwZD.png&quot; alt=&quot;Laskar 1986 Creative common Wikimedia&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Change in axial tilt over time from Laskar (1986)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We cannot remove the tilt completely, but we can look at the constant axial tilt change in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;nofollow noreferrer&quot;&gt;Milankovitch cycles&lt;/a&gt;. Some believe that the impact of this 2.4° change is rather large. &lt;a href=&quot;http://clivebest.com/blog/?p=7300&quot; rel=&quot;nofollow noreferrer&quot;&gt;Clive Best blog&lt;/a&gt; gives the main arguments and suggests some good references. See also &lt;a href=&quot;https://wattsupwiththat.com/2014/01/14/do-super-tides-kick-start-interglacials/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this discussion&lt;/a&gt; and &lt;a href=&quot;http://www.pnas.org/content/97/8/3814.abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt; on tidal change and glaciation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it's difficult to specify how much of the impact that is directly related to the tilt change, as sea level change and glaciation also affects and interacts with the tides pattern. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EiZ9e.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EiZ9e.png&quot; alt=&quot;Figure from Wilmes and Green 2014&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;This model from Wilmes and Green (2014) suggests much higher tides at high latitudes during LGM, 21.000 years ago. The model is based on changes in sea-level and glaciation.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the astronomical data, it however does appear that the impact (tractional acceleration) of the Moon was much higher at large latitudes when the obliquity of the tilt is large (see figure) and this resulted in higher tides at latitudes where glaciation forms. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With less or no tilt, tides at large latitudes should be even smaller and maybe contribute to less breakup of ice sheets. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastActivityDate="2016-08-29T09:33:22.677" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8660" PostTypeId="2" ParentId="8648" CreationDate="2016-08-29T15:55:34.060" Score="5" Body="&lt;p&gt;A simple way to estimate the implications is to simplify the problem. If the orbits of Earth, Sun and Moon were circular and in the same plane, and the Earth had no tilt, the only remaining tidal constituents would be $M_2$ and $S_2$ (also the overtides and combination tides: $M_4$, $MS_4$...). The rest of the tidal constituents can be expressed as linear combinations of their rates of change based on the remaining forcings: &lt;a href=&quot;https://en.wikipedia.org/wiki/Orbital_eccentricity&quot; rel=&quot;nofollow noreferrer&quot;&gt;orbital eccentricity&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Orbital_inclination&quot; rel=&quot;nofollow noreferrer&quot;&gt;inclination&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Axial_tilt&quot; rel=&quot;nofollow noreferrer&quot;&gt;axial tilt&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The modulation of the amplitude $A_M$ of the main constituent wave, $\eta_M = A_M cos (\omega_M t)$, by another constituent of amplitude $A_c$ is: $\eta_t= (A_M+A_ccos(\omega_c t))cos(\omega_Mt)$. Expressing it as a linear combinations of the rates of change gives $\eta_t= A_Mcos(\omega_Mt)+{A_c\over2}cos(\omega_M-\omega_c)t+{A_c\over2}cos(\omega_M+\omega_c)t$, such that the original amplitude remains unchanged, while two extra components with slightly different frequencies appear.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case of the effect of the axial tilt, it modulates the main frequencies based on the solar parameters (the inclination of the Moon orbit is not affected by the axial tilt). The period of the solar declination is a sidereal year (365.2564 days). In the case of the modulation of the $M_2$, the resulting periodicities are 1 cycle/solar day &amp;plusmn; 1 cycle/sidereal year. The two resulting constituents are $P_1$ and $K_1$. $P_1$ is known as the solar declinational diurnal constituent. The case of $K_1$ is slightly more complex as the inclination of the Moon also results in a contribution at this frequency. The rest of the tidal constituents are also modified accordingly, but their amplitudes are much smaller.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;In short, the removal of the axial tilt will result in the removal of the $P_1$ tidal constituent (and some other minor ones) and an amplitude decrease in the $K_1$ constituent.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nzx2Z.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nzx2Z.gif&quot; alt=&quot;K1 from AVISO&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$K_1$ amplitude and phase from &lt;a href=&quot;http://www.aviso.altimetry.fr&quot; rel=&quot;nofollow noreferrer&quot;&gt;AVISO&lt;/a&gt;. The maximum $K_1$ amplitudes of around 0.4m are found south of Alaska and west of the Kamchatka Peninsula in the Sea of Okhotsk. The &lt;a href=&quot;https://www.mikepoweredbydhi.com/-/media/shared%20content/mike%20by%20dhi/flyers%20and%20pdf/product-documentation/mike-21-toolbox-global-tide-model.pdf?la=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;amplitude of the $P_1$ constituent&lt;/a&gt; is about half of $K_1$ with a maximum of around 0.2m in the Sea of Okhotsk. Overall, the effect of the tilt on tides is pretty minor relative to the rest of the effects.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2016-08-29T15:55:34.060" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8661" PostTypeId="1" AcceptedAnswerId="8667" CreationDate="2016-08-29T22:28:57.550" Score="2" ViewCount="218" Body="&lt;p&gt;I love looking at clouds. I love trying to describe them and compare what I see day to day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have dozens of questions about the things I’ve observed and I would really like to understand the physics of the world around me. Today I would like to focus on the surface dynamics of cumulus clouds.&#xA;Why do some cumulus clouds have distinct textured surface while others are softer and wispy at the edge?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I imagine it probably comes down to temperature and pressure. It may also be an effect of direct sunlight, I’m not sure. I notice the soggy cotton clouds are more common in the evening and the billowy ice cream clouds are more common mid-day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do clouds have surface tension like liquid water?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does the flow of water either into or out of a cloud affect its surface characteristics?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/LASSj.jpg&quot; alt=&quot;Textured cloud&quot;&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/eCL2g.jpg&quot; alt=&quot;Soft cloud&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="6526" LastActivityDate="2016-08-30T09:28:04.753" Title="What affects the surface characteristics of cumulus clouds?" Tags="|atmosphere|clouds|fluid-dynamics|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8662" PostTypeId="1" CreationDate="2016-08-30T04:41:44.940" Score="4" ViewCount="237" Body="&lt;p&gt;At lat +50.0 on Jun 21 and lat -50.0 on Dec 21 is the time between sunrise and sunset exactly the same?  And so on throughout the parallels and the days of the year?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If not can you explain why?  I once read something about the earth's wobble on its axis means that daylight length is not symmetrical north to south.&lt;/p&gt;&#xA;" OwnerUserId="6528" LastActivityDate="2016-08-30T04:41:44.940" Title="Is daylight time symmetrical between northern and southern hemisphere?" Tags="|earth-rotation|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8663" PostTypeId="1" CreationDate="2016-08-30T06:34:50.170" Score="6" ViewCount="4452" Body="&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;If gravitation decreases as we approach the core and if density is a function of gravity we should expect a void core.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Unless the accretion disk was formed starting with the objects of highest mass available first.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;But as soon as the whole planet would have been liquefied the core should have voided according to 1.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="6529" LastEditorUserId="2536" LastEditDate="2016-08-30T07:16:00.650" LastActivityDate="2022-05-24T19:16:36.527" Title="Why is the density of Earth higher at the core" Tags="|geophysics|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8665" PostTypeId="1" CreationDate="2016-08-30T07:20:26.787" Score="4" ViewCount="112" Body="&lt;p&gt;Tectonic plate motion is the main reason for earthquakes in Italy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suppose that a large motion produces higher mountain (as Monte Bianco, Monte Rosa or Adamello) and strong earthquakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But strong earthquakes are usually registered in the Apennines (not so high, with the exception of Gran Sasso) and the Julian Alps (not very high between Italy, Austria and Slovenia).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the reason of this counter-intuitive behavior? &lt;/p&gt;&#xA;" OwnerUserId="6530" LastEditorUserId="595" LastEditDate="2016-08-30T10:46:10.060" LastActivityDate="2016-08-30T13:14:55.013" Title="Earthquakes and mountain height" Tags="|earthquakes|plate-tectonics|mountains|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8666" PostTypeId="2" ParentId="8663" CreationDate="2016-08-30T08:01:48.593" Score="4" Body="&lt;p&gt;Maybe there is some confusion between weight and density / specific gravity. The weight = mass x acceleration. True, the gravitational attraction is zero at the centre of the earth, but everywhere else there is some gravity acting on a huge density contrast. Also there is the question of incompatibility between siderophile and lithophile elements. During the initial hot phase of planetary formation it wouldn't have taken much gravity to differentiate the two liquid phases.&#xA;That said, it is possible that some residual non Fe-Ni lighter elements could be lurking within the core - sulphur and hydrogen (as metal hydrides) have been widely cited as possibilities. The main evidence being that the true density, as determined by geophysics, is slightly less than it should be if it it was just nickel-iron (+ a few heavier elements). &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-30T08:01:48.593" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8667" PostTypeId="2" ParentId="8661" CreationDate="2016-08-30T09:23:00.647" Score="2" Body="&lt;p&gt;No, clouds don't really have a 'surface' that could have tension like a body of water. The different looks in these two examples (left Cumulonimbus Calvus and right Cumulus Humilis) are greatly dependent on how they have formed and how are they evolving now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The large Cumulonimbus is still growing in a relatively rapid speed. The cloud is reaching higher and higher upwards carrying moist air. The moist air due to turbulent flows and expanding of the rising air gets mixed with the cold air and instantly forms/extends cloud as it reaches saturation (saturation is reached with less water in colder air and air is colder in higher altitudes). If there wasn't the expansion then flows of dry air to the cloud would desaturate the cloud and more small scale variation could be seen as in the Cumulus Humilis. Also the Cumulonimbus being much larger and further away looks different just due to distance. The steady state like situation of the Cumulus Humilis where it isn't growing (perhaps a little on the top) and the fact that the lower atmosphere has stronger turbulent motions equals to the appearance where more cotton candy pieces 'drift' from the cloud.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Neither of these are ice droplet clouds (they look different just because they are made of ice and not water droplets), but all clouds that are in freezing temperatures have some very small percentage of ice in them too. The Cumulus Humilis might be below 0 Celsius and the Cumulonimbus definitely is at some height. A crude estimate is that temperature drops 6 Celsius every kilometer. The base of both clouds is probably somewhere between 1 and 2.5 kilometers and the Cumulonimbus might reach over 10 kilometers.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastEditorUserId="6465" LastEditDate="2016-08-30T09:28:04.753" LastActivityDate="2016-08-30T09:28:04.753" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8668" PostTypeId="2" ParentId="8665" CreationDate="2016-08-30T13:14:55.013" Score="1" Body="&lt;p&gt;Present earthquakes create new mountains, former earthquakes created old mountains.&#xA;Hence, the Alps are older than the Appenines. In the past surely the Alps had more earthquakes than now.&lt;/p&gt;&#xA;" OwnerUserId="5004" LastActivityDate="2016-08-30T13:14:55.013" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8669" PostTypeId="2" ParentId="4964" CreationDate="2016-08-30T15:40:23.283" Score="0" Body="&lt;p&gt;Most times it does not happen, but there are many factors involved and in part it depends on your definition of triggering.  As a general rule, earthquakes are considered to occur when the stress on one section of plate becomes too great and the plate slips, surges, or in some way moves to relieve the stress.   The plates though are large, relatively solid objects, so slippage in one location to relieve stress is likely to increase it in other locations, some close, some far away.  This increase in stress should tend to be spread out, and much less that what was built up and caused the quake as some of that energy is dissipate through the quake, but not all.  If another section of that plate, or potentially even an unrelated plate was at or near its stress limit also, sure, that added energy could be the straw that breaks it loose.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The added energy from one quake is not really likely to be the cause per say of another large quake in a seemingly unrelated fault, but it could be the energy that causes it to pass its tipping point, and thus considered a trigger.  The triggered quake could even be much large that the original quake.  The second quake was going to occur anyway.  The energy was already there and ready to be release, the jolt it got was simply the last push needed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When two quakes occur, you will normally hear if you listen to reliable reports, statements that the two are not considered related.  That is normally the case, but each time the seismologists look at the patterns and make that call based on their opinions.  Sometimes they will decide they actually were related, but not often at least for large quakes.&lt;/p&gt;&#xA;" OwnerUserId="6178" LastActivityDate="2016-08-30T15:40:23.283" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8670" PostTypeId="1" AcceptedAnswerId="8671" CreationDate="2016-08-30T16:14:27.280" Score="5" ViewCount="894" Body="&lt;p&gt;Many years ago, I found a piece of rock on a lakeside in Switzerland (see picture below).&#xA;I think that it could be a &quot;fossil&quot; from some &lt;em&gt;Pecten&lt;/em&gt; species (do you agree?).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;My question is: how old such a fossil can be, approximately? Is it like 1000 years, or rather 1'000'000 years?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I have no idea, that's why I just would be interested to have your opinion on this topic.&#xA;I don't know if it is frequent or rather uncommon to find such &quot;fossils&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you for your help!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kOqXe.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kOqXe.jpg&quot; alt=&quot;pecten&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6525" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T07:09:50.190" LastActivityDate="2023-01-07T23:47:14.513" Title="How old are Pecten fossils in general?" Tags="|fossils|paleontology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8671" PostTypeId="2" ParentId="8670" CreationDate="2016-08-31T01:39:46.077" Score="5" Body="&lt;p&gt;&lt;em&gt;Pectens&lt;/em&gt; seem to have evolved from &lt;em&gt;Chlamys&lt;/em&gt; in the late Eocene or early Oligocene. The coarseness and rib spacing of &lt;em&gt;Vertipectens&lt;/em&gt; has been slowly evolving since the early and Mid-Miocene, so they have been around for at least 16 million years, maybe up to 20 million years. If you want to be precise you will need to read-up on the fine detail. Pectens are a classic case of 'ontogeny recapitulating phylogeny', and their identification is complicated by parallel and convergent evolution of different species. As fossils, they are quite common, and probably more useful as indicators of the palaeo-environment, than as age indicators. Where you find such fossils you will very likely find associated micro-fossils in the same rock, which are more diagnostic of age. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-08-31T01:39:46.077" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8672" PostTypeId="1" AcceptedAnswerId="8673" CreationDate="2016-08-31T04:46:45.143" Score="11" ViewCount="1241" Body="&lt;p&gt;It has been suggested that global warming will lead to increased precipitation in parts of Antarctica. This would sequester water in the ice sheet, preventing sea level rise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the slope (and thus the height and volume) of continental ice sheets is limited by ice properties. What if the ice sheet is already at its maximum slope/height/volume (is this known)? Wouldn't adding more ice just cause more flow to the sea?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;http://www3.geosc.psu.edu/~dmb53/DaveSTELLA/Glaciers/Ice%20Sheet%20Model.pdf&quot; rel=&quot;nofollow&quot;&gt;&quot;Ice Sheet Modeling&quot;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;ice behaves as a deformable plastic material, which means that there&#xA;  is a critical shear stress, below which no strain (deformation or&#xA;  flow) will occur ... If the slope is too low, the basal shear stress&#xA;  will not match the critical shear stress, ... but as snow piles up,&#xA;  ... flow will begin. ... The result of this is that a glacier has an&#xA;  equilibrium profile&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I am presuming that the ice sheets are already slightly above their equilibrium profile (since they are flowing). Since the profile depends on the area and shape of the base (which is shrinking due to melting around the edges), they are already holding as much ice as possible, and adding more snow to any region will just accelerate the flow. I don't know on what timescale this occurs. (I have not tried the computer models described in the paper.)&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="20" LastEditDate="2016-09-01T01:11:56.513" LastActivityDate="2016-09-09T11:24:46.567" Title="Will increased precipitation in Antarctica prevent sea level rise?" Tags="|climate-change|sea-level|glaciology|ice-sheets|" AnswerCount="3" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8673" PostTypeId="2" ParentId="8672" CreationDate="2016-08-31T06:20:33.183" Score="12" Body="&lt;p&gt;There is some scope for continuing debate because quantifying the various components of the ice/snow/water balance are fraught with difficulty, and many of the estimates have error bounds which approach the magnitude that is being measured. However, a good best estimate, subject to continuing research, is given in:&lt;a href=&quot;https://www.skepticalscience.com/antarctica-gaining-ice.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Is Antarctica losing or gaining ice?&lt;/a&gt; &#xA;This cites the following two graphs:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dLW9C.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dLW9C.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clearly there are important regional differences, with East Antarctica gaining slightly, but not enough to compensate for the ice loss in west Antarctica. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is true that the amount of fresh snow in the Antarctic is increasing, but it still doesn't amount to much. Antarctica is still the driest continent, by far, and much more so than Australia. The controlling factor is not the amount of snow on the land, but the fate of the sea ice around the perimeter. Notwithstanding climate deniers, there is abundant evidence that the oceans' sea surface temperatures are warming, including the Southern Ocean. This reduces the seasonal extent and thickness of sea ice, which lowers the oceanic albedo, and increases near-surface heat absorbtion. It is a well-documented feedback process. Overall the warmer ocean around Antarctic destabilizes the shelf ice, thereby unlocking the glacial ice which would have been held back. So we have two opposing non-linear processes, mobilization of coastal land ice (mass loss), vs increased snowfall (mass gain). At present, and for the forseable future, the mass-loss is winning. I'm guessing this will continue to be the case because the negative feedback is very powerfull. I don't think there are any reliable forward projections about how precipitation in the Antarctic will evolve. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Later) In view of the comments, maybe it would be helpful to visualize the daily precipitable moisture around the world. This is available at &lt;a href=&quot;http://www.eldoradocountyweather.com/climate/world-maps/world-precipitable-water.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;El Dorado Weather.&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="6093" LastEditDate="2016-09-09T11:24:46.567" LastActivityDate="2016-09-09T11:24:46.567" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8674" PostTypeId="2" ParentId="8672" CreationDate="2016-08-31T13:24:25.517" Score="3" Body="&lt;p&gt;Drifting into what-if territory (and apologies for the lousy units) :  Let's pick a rough rule of thumb that 30 inches of ( cold temperature) snow is equivalent to one inch of water.   The land area of Antarctica is 5.4 million square miles.  The world's major oceans' total area is roughly 140 million square miles (all data from Wikipedia).  Thus, to reduce sea level by one inch, you'd need to dump 26 inches of water onto Antarctica, or maybe 620 inches of snow.  To drop sea level by, say two feet, then, you'd need 19000 inches, aka 1560 feet, or 5.2 football fields, of snowfall.&lt;br&gt;&#xA;Since some ice will break back into the sea, we'll need more snow to fall than is lost to icebergs -- but so long as the snowfall exceeds lost ice by any amount, the sea level will decrease (albeit slowly :-) ).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do want to emphasize that this is a what-if answer (without the funny drawings or velociraptors), not a suggestion of what could possibly happen in the real world. &lt;/p&gt;&#xA;" OwnerUserId="1140" LastActivityDate="2016-08-31T13:24:25.517" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8675" PostTypeId="1" CreationDate="2016-08-31T15:45:42.573" Score="9" ViewCount="226" Body="&lt;p&gt;When downscaling meteorological data by using limited area models, many support forums recommended you to downscale incrementally in small steps. For example let's assume that your input data is on a 27x27 km resolution and you need data on 1x1 km resolution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A suitable setup would be to downscale in three steps, incrementally increasing the resolution:&#xA;27 km -&gt; 9 km -&gt; 3 km -&gt; 1 km&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why should I not simply use the following set-up?&#xA;27 km -&gt; 1 km&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main motivations I've seen for this is that the intermediate domains (9 &amp;amp; 3 in the example) won't require that much computational resources compared to the final domain (1 km). But that can't be the only reason. &lt;/p&gt;&#xA;" OwnerUserId="2505" LastEditorUserId="111" LastEditDate="2016-09-01T18:48:03.743" LastActivityDate="2016-09-01T18:48:03.743" Title="Why should dynamical downscaling of meteorological data be made incrementally?" Tags="|meteorology|atmosphere-modelling|numerical-modelling|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8676" PostTypeId="2" ParentId="8672" CreationDate="2016-08-31T18:31:28.517" Score="-1" Body="&lt;p&gt;I want to support other arguments with the historical one. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;All we know that since the Last Ice Age the Sea Level has increased by .. &lt;a href=&quot;https://en.wikipedia.org/wiki/Sea_level_rise&quot; rel=&quot;nofollow noreferrer&quot;&gt;120 meters&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iTn5j.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iTn5j.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For some reason (I guess explained by now: it is too small and experiencess net loss of ice instead of build up), Antarctica did not stop the raise. Antarctica never hampered the sea level rise and fall along with the global temperature. Which magic do you expect to turn the tide? Why should antropogenic nature of the human-induced warming should revert the trend?&lt;/p&gt;&#xA;" OwnerUserId="6272" LastEditorUserId="6272" LastEditDate="2016-09-01T14:55:01.880" LastActivityDate="2016-09-01T14:55:01.880" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8677" PostTypeId="1" CreationDate="2016-09-01T06:50:59.917" Score="2" ViewCount="5811" Body="&lt;p&gt;Does the amount of rainfall relate to temperatures of a place? Is the amount of rainfall related to the maximum mean temperature of a place? &lt;/p&gt;&#xA;" OwnerUserId="6517" LastEditorUserId="725" LastEditDate="2016-09-04T10:54:20.580" LastActivityDate="2016-09-04T10:54:20.580" Title="Does the amount of rainfall relate to temperatures of a place?" Tags="|temperature|precipitation|rainfall|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8679" PostTypeId="2" ParentId="8675" CreationDate="2016-09-01T16:27:39.003" Score="2" Body="&lt;p&gt;The basic answer to your question is that there needs to be an overlap between the spectra of the two domains. One way to think about it is that there needs to be a connection between the Kolmogorov energy cascades (&lt;a href=&quot;https://en.wikipedia.org/wiki/Energy_cascade&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Energy_cascade&lt;/a&gt;) of the two domains. &lt;a href=&quot;https://i.stack.imgur.com/FGjXk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FGjXk.png&quot; alt=&quot;Kolmogorov energy cascade&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://ffden-2.phys.uaf.edu/647fall2013_web.dir/j_stroh/tec.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kolmogorov energy cascade (D. Newman, U. Alaska Fairbanks)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each domain is going to be forced (have energy input) at a relatively large scale and it is going to assume that the energy that it can't resolve at sub-grid scales is going to be dissipated. If there is no (or little) overlap between the two grid resolutions, the energy from the large domain (parent) will be dissipated by viscosity at sub-grid scales that the small domain (child) cannot resolve and there is not going to be an appropriate input of energy from the parent to the child. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason for the odd numbers in the ratio is given in &lt;a href=&quot;https://earthscience.stackexchange.com/questions/8067/why-is-wrf-most-often-configured-at-31-nesting-ratio&quot;&gt;Why is WRF most often configured at 3:1 nesting ratio?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-09-01T16:27:39.003" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8680" PostTypeId="1" CreationDate="2016-09-02T02:22:49.480" Score="5" ViewCount="90" Body="&lt;p&gt;What are the largest eddies within the planetary boundary layer? What timescales do the operate on?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: I'm talking about atmospheric eddies over land. So, eddies that are measured in [eddy covariance[(&lt;a href=&quot;https://en.wikipedia.org/wiki/Eddy_covariance&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Eddy_covariance&lt;/a&gt;), for instance.&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="56" LastEditDate="2016-09-05T00:40:09.303" LastActivityDate="2016-09-05T00:40:09.303" Title="What timescales do eddies operate at in the planetary boundary layer?" Tags="|atmosphere|land-surface|planetary-boundary-layer|eddies|" AnswerCount="0" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8682" PostTypeId="2" ParentId="8677" CreationDate="2016-09-03T00:33:38.740" Score="1" Body="&lt;p&gt;Assume you mean surface temperature...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think you should not directly try to correlate temperature and precipitation together.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both of them are, in general, determined by location, which represents solar radiation level (related to latitude), altitude, distance to nearby water bodies (source of moisture), impacts of atmospheric circulations and ocean currents, and so on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus there should not exist any global correlation between these two factors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, in a certain area, they may be related, and I think there may exist another deterministic factor, e.g. distance towards nearby mountains.&lt;/p&gt;&#xA;" OwnerUserId="6447" LastEditorUserId="6447" LastEditDate="2016-09-04T06:17:16.733" LastActivityDate="2016-09-04T06:17:16.733" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8683" PostTypeId="1" CreationDate="2016-09-03T07:58:24.320" Score="2" ViewCount="90" Body="&lt;p&gt;How can parameters of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ionosphere&quot; rel=&quot;nofollow&quot;&gt;ionosphere&lt;/a&gt; be calculated? Specifically, how do we calculate total ion density, total ion temperature and individual major ion densities from I-V Characteristics curve of ionospheric plasma. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Current%E2%80%93voltage_characteristic&quot; rel=&quot;nofollow&quot;&gt;I-V characteristics&lt;/a&gt; curve is obtained using ion Retarding Potential Analyzer (RPA) onboard a spacecraft.&lt;/p&gt;&#xA;" OwnerUserId="6546" LastEditorUserId="543" LastEditDate="2016-09-03T13:39:31.983" LastActivityDate="2020-02-19T04:05:30.657" Title="How can parameters of the ionosphere be calculated?" Tags="|atmosphere|earth-observation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8684" PostTypeId="1" CreationDate="2016-09-03T07:59:44.840" Score="4" ViewCount="401" Body="&lt;p&gt;What is the biggest and longest periodic river in the world ? (river that runs dry on occasion and flows during a season of heavy rain)&lt;/p&gt;&#xA;" OwnerUserId="6549" LastActivityDate="2016-09-03T07:59:44.840" Title="What is the biggest periodic river?" Tags="|rivers|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8685" PostTypeId="1" CreationDate="2016-09-03T08:59:01.930" Score="3" ViewCount="148" Body="&lt;p&gt;I am studying about World Magnetic Model (WMM) and International Geomagnetic Reference Field (IGRF) model provides the seven parameters about the earth magnetic field. These models have to be deployed on the nano satellite now i am confused how these models works.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I got one formula for the potential of the field and after taking partial derivative of that formula getting the field strength in the respective direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But is there any way to get the satellite attitude by that model and having magnetometer reading. Please give any idea if have.  &lt;/p&gt;&#xA;" OwnerUserId="3337" LastActivityDate="2016-09-03T08:59:01.930" Title="WMM and IGRF model?" Tags="|earth-observation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8686" PostTypeId="1" CreationDate="2016-09-03T17:04:25.383" Score="5" ViewCount="436" Body="&lt;p&gt;For chlorophyll-a, measured in mg/m3, what are the average values for:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Open ocean in general (global)&lt;/li&gt;&#xA;&lt;li&gt;Northen latitudes (N. Atlantic Ocean)&lt;/li&gt;&#xA;&lt;li&gt;Coastal waters around the UK (North sea, Irish Sea, etc)&lt;/li&gt;&#xA;&lt;li&gt;equatorial waters &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Is there any pattern regarding plankton productivity and ocean climate that would help answer this? I.e. warmer waters with higher levels of sunshine (Mediterranean) have higher productivity, than colder waters (North Atlantic). Or are there too many factors involved (stratification, eutrophication) to generalise for the oceans?   &lt;/p&gt;&#xA;" OwnerUserId="5923" LastActivityDate="2016-12-21T20:06:23.323" Title="What is the average cholorphyll concentration for the ocean?" Tags="|ocean|satellites|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8687" PostTypeId="2" ParentId="8677" CreationDate="2016-09-03T20:18:50.007" Score="2" Body="&lt;p&gt;Yes, with exceptions &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rainfall is related to temperature. However temperature is not the only thing that dictates rainfull. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, the more hot a place is, the more water evaporates and the more rainfall is able to be produced. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, the equator has a belt of rain-forests precisely because it receives the highest amount of heat from the sun and thus high amounts of rain-fall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, not all hot places make a lot of rain. Deserts occur when there is a lack of rain fall. Yet deserts can occur in cold temperatures (the north pole) and hot temperatures (Sahara desert).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To sum, temperature is certainly related to the amount of rainfall. However, you can't just presume the level of rainfall by temperature as many other factors are invovled. &lt;/p&gt;&#xA;" OwnerUserId="5923" LastActivityDate="2016-09-03T20:18:50.007" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8689" PostTypeId="2" ParentId="2486" CreationDate="2016-09-04T13:01:49.450" Score="5" Body="&lt;p&gt;Gerrit is correct that the atmosphere is not becoming &lt;em&gt;significantly&lt;/em&gt; denser, but it is becoming &lt;em&gt;marginally&lt;/em&gt; denser, actually by about 0.02%, because CO2 is about 1.5 x denser than air, and we have increased it by about 120 ppm since the start of the industrial revolution. In the short term this is a worry, but in the long term, geologically speaking, it is a mere blip in the Earth's evolving atmosphere - like major volcanic eruptions. Out-gassing of radiogenic helium is insignificant, as is incoming gaseous debris from space. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Refracted solar insolation doesn't significantly vary with changing atmospheric density, and even if it did, it would only be an imperceptible and trivial influence upon where the sunlight was absorbed - merely a local thermal anomaly, very rapidly redistributed by the weather.  &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-09-04T13:01:49.450" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8692" PostTypeId="1" CreationDate="2016-09-04T22:54:05.287" Score="4" ViewCount="1735" Body="&lt;p&gt;The Inclusive graphic standard deviation (sorting) value of this claystone sample is negative (-1.29). Is this right to be considered as very well sorting ? However, the bivariate plots of depositional environment do not include negative values on the axis of the standard deviation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: The granulometric data was obtained by laser diffraction technique. &lt;a href=&quot;https://i.stack.imgur.com/l5q6r.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/l5q6r.jpg&quot; alt=&quot;Particle Size Distribution of a claystone sample&quot;&gt;&lt;/a&gt;&#xA;The formula of the inclusive graphic standard deviation after Folk 1974:&#xA;$\sigma_1 = \frac{\phi_{84} - \phi_{16}}{4} + \frac{\phi_{95} - \phi_{5}}{6.6}$&lt;/p&gt;&#xA;" OwnerUserId="6558" LastEditorUserId="725" LastEditDate="2016-09-10T09:03:42.677" LastActivityDate="2021-09-12T11:11:28.273" Title="Sedimentology (Particle size distribution parameters)" Tags="|geology|sedimentology|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8693" PostTypeId="2" ParentId="2486" CreationDate="2016-09-05T12:21:03.827" Score="3" Body="&lt;p&gt;Regarding the last part of your question. The atmosphere keeps temperature of the Earth warmer than it would be without it not because of lensing but because of the greenhouse effect. The light from the sun hits the ground, heats it up and hot ground emits the thermal radiation, like your back burner. The greenhouse gases capture it. The thicker is the atmosphere, the higher is the probability that low-freq thermal radiation will be turned back to Earth (Sun is much hotter, it emits much higher-freq light, the atmosphere is transparent for it). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You say that there can be another effect, the photons which fly tangent to the earth surface can be captured by the atmopsphere (lens) and deflected to the ground, like if you capture a fly that passes near you with your hand, and sent it into your mouth. It seems that the effect is real and known as &lt;a href=&quot;https://sites.google.com/a/apps.district279.org/lightapplicationslucysaidu/refraction&quot; rel=&quot;nofollow noreferrer&quot;&gt;atmospheric refraction&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/q90J5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/q90J5.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can feel it on the sunraises and sunsets, when the sun is behind the horizon, the atmosphere is still light, which means that it captures some light, the photons that go tangent to the earth surface and would pass by if atmosphere did not capture it. That is, the lens cannot produce more photons than Earth receives from the sun. It cannot raise the Earth temperature. It can only collect all the light and send it into one dot or grow bigger, collecting some light from outside the Earth and send it to the Earth, like capturing the flies near your body with long hands. Let's suppose that refraction is real and atmosphere can capture the tangent photons. So, the question is: which effect is stronger: greenhouse warming or lensing warming? The thicker atmosphere increases both of them. But, the diagram is misleading. It says that the atmosphere is very fat, almost like the Earth diameter or larger, which is far from truth. In fact, the atmosphere is only a couple of kilometers in thickness whereas the Earth is 6000 km. Morevover, refraction operates only on the perimeter area, the &lt;a href=&quot;http://bugs.kerbalspaceprogram.com/issues/7741&quot; rel=&quot;nofollow noreferrer&quot;&gt;rim around the earth&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Cae4s.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Cae4s.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;whereas greenhouse gases reflect the Earth heat back to the surface over the whole earth surface, which makes the effect not 1000 times smaller but 1000x1000 times smaller. So, I would account your lensing as important only when atmosphere sichness would reach the size of the Earth and beyond. There is however one negative feedback that I cannot estimate but it would be important for a very large atmosphere. It is that surface of heat irradiation would also be much larger if your planet is much larger. Probably your lensing gives less warm than increased irradiation takes away.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Enough of speculations for today, I suppose. &lt;/p&gt;&#xA;" OwnerUserId="6272" LastActivityDate="2016-09-05T12:21:03.827" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8696" PostTypeId="2" ParentId="8578" CreationDate="2016-09-07T08:23:39.037" Score="3" Body="&lt;p&gt;If you're interested in in the cause of climate change from a scientific perspective and how the climate system science have evolved I highly recommend &lt;a href=&quot;http://eu.wiley.com/WileyCDA/WileyTitle/productCd-1405196165.html&quot; rel=&quot;nofollow&quot;&gt;&lt;em&gt;The Warming Papers&lt;/em&gt;&lt;/a&gt; by David Archer and Raymond Pierrehumbert. It is a commented compendium of classic scientific papers forming the basis of the science of climate change and anthropogenic global warming.&lt;/p&gt;&#xA;" OwnerUserId="2789" LastActivityDate="2016-09-07T08:23:39.037" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8697" PostTypeId="1" CreationDate="2016-09-07T13:20:42.917" Score="1" ViewCount="189" Body="&lt;p&gt;I regularly watch both the above said satellite images for India, particularly for chennai. I notice there is lot of difference between the two. Which one is accurate to foresee the rains ?.Generally, I observe and correlated the actual rains with the satellite picture of meteostat is nearly  coinciding.&lt;/p&gt;&#xA;" OwnerUserId="6567" LastActivityDate="2016-09-07T13:20:42.917" Title="Which image is accurate viz insat or meteostat?" Tags="|satellites|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8698" PostTypeId="1" AcceptedAnswerId="8701" CreationDate="2016-09-07T15:33:22.020" Score="3" ViewCount="109" Body="&lt;p&gt;I know that WRF has many different uses and options, from atmospheric chemistry to uses with fires, and so on. What exactly denotes a parameterization? For example, in WRF-Chem, is the chemistry considered a parameterization? If not, what separates a mechanism from a parameterization? Is photolysis a parameterization? Are the biogenic emissions parameterized?&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2016-09-08T14:27:10.373" Title="What denotes a parameterization in a model? (semantics )" Tags="|atmospheric-chemistry|wrf|wrf-chem|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8699" PostTypeId="2" ParentId="8663" CreationDate="2016-09-08T03:15:50.387" Score="6" Body="&lt;h2&gt;Pressure&lt;/h2&gt;&#xA;&lt;p&gt;answers the question as posed in the title. (The assertions in the question body are just too preposterous to address.) Matter deep in the Earth has the weight of all the matter above pressing it down. &lt;a href=&quot;https://physics.stackexchange.com/questions/184032/what-is-the-pressure-at-the-center-of-the-earth-or-a-neutron-star&quot;&gt;This post&lt;/a&gt; explains how high that pressure can get.&lt;/p&gt;&#xA;&lt;p&gt;Although it is true that gravity is zero at a single point at the very center of the Earth, where gravitational vectors completely cancel each other out, it is &lt;em&gt;never&lt;/em&gt; negative.  Nothing is pulling matter away from the center. There can be no void. Premise 1 in the body of the question is simply wrong.&lt;/p&gt;&#xA;&lt;p&gt;Furthermore, everywhere away from that single point, there is a little bit of gravity left over from the vector sum.  The direction of that result vector is always towards the center (given some allowance for the Earth's equatorial bulge).&lt;/p&gt;&#xA;&lt;p&gt;The micro- (and even zero-) gravity at the center of the earth is more than made up for by the pressure of the entire Earth holding it in place, trying to squeeze it down to a point.&lt;/p&gt;&#xA;&lt;p&gt;This was true even when the Earth was molten, so the heavier elements tended to  sink down to the center. &lt;a href=&quot;https://physics.stackexchange.com/questions/165526/if-the-gravity-at-the-center-of-the-earth-is-zero-why-are-heavy-elements-like-i&quot;&gt;This other post&lt;/a&gt; has a thorough explanation as to why.&lt;/p&gt;&#xA;&lt;p&gt;Now that the Earth has cooled somewhat, pressure deep in the Earth increases local density by forcing liquids (e.g. the liquid outer core) into a solid state (the solid inner core), and then as the pressure increases, solids shift into new, more tightly packed crystal structures.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2022-05-24T19:16:36.527" LastActivityDate="2022-05-24T19:16:36.527" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="8700" PostTypeId="2" ParentId="8663" CreationDate="2016-09-08T04:13:15.813" Score="5" Body="&lt;p&gt;Gravity is a weird force.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All mass has, and is affected by, gravity. That means you, me, your cat, black holes, the sun and the earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It also means each little bit of the earth is attracted to every other little bit. So every bit tries to get as close to every other bit as it can.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The shape that these bits form is a sphere - because every bit is as close as it can get to all the other bits.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now you are right - an earth which is matter all the way through would attract in the same way as one which had all the mass concentrated around the edge. But we know that the centre isn't hollow for two reasons:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.flickr.com/photos/coolinsights/5127279893&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/y3OVIm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:ADBC_Branch_in_BeiChuan_after_earthquake.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VyY14m.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Volcanoes and Earthquakes. Volcanoes erupt liquid rock from the ground, which shows that there is something down there. And we know that there is something because we feel the shaking from earthquakes on the other side on the earth - and we can map the layers of solid and liquid from these.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ol&gt;&#xA;  &lt;li&gt;If gravitation decreases as we approach the core and if density is a function of gravity we should expect a void core.&lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No, because every bit wants to be close to &lt;em&gt;every other bit&lt;/em&gt;. It doesn't just want to be near the bits on it's side, it wants to be near the ones on the other side, and so the &quot;void&quot; would close.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Why is the density of Earth higher at the core?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The denser stuff sinks. This is how it works everywhere that gravity applies. We can explain why.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The denser objects have more gravity than the less dense objects. This means all the objects are attracted to the more dense objects more than they are the less dense objects. Here, red is more dense.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YSW7Dm.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YSW7Dm.png&quot; alt=&quot;&quot;&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/f7Mx8m.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/f7Mx8m.png&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the ones over the other side, are also attracted to that dense object, so this happens:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EMbL1m.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EMbL1m.png&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Eventually, you end up with all the less dense objects surrounding the more dense object, as they try to be as close as they can to it. But the more dense objects are attracted &lt;em&gt;more&lt;/em&gt; to the other dense objects (as they both have more mass). This means all the dense objects clump together, surrounded by the less dense ones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3AKUY.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3AKUY.png&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3109" LastActivityDate="2016-09-08T04:13:15.813" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8701" PostTypeId="2" ParentId="8698" CreationDate="2016-09-08T08:23:47.240" Score="6" Body="&lt;p&gt;As defined in the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Parameterization&quot;&gt;AMS glossary&lt;/a&gt;, a parameterization is a simplification of one or several processes in a model. I add that a parameterization commonly adds an error and increases the uncertainty in the model results. In most cases, a parameterization is not derived from physical laws but a fit to data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These simplifications are employed for different reasons. You probably know the following examples and this answer could have been shorter ;-) but I added them for other readers who might not be aware of them.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Parameterization due to spatial constraints&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;When we model meteorological and atmospheric chemistry processes in a certain domain, we split this domain into individual grid cells of a given size - such as grid cells of 10 km x 10 km size. Some atmospheric processes have a lower spatial extend than the grid cells - such as small scale turbulence and clouds smaller than 10 km. These things cannot be explicitly calculated by the model (except if we reduce the model resolution). Therefore, we approximate these things taking place on a spatial scale below 10 km. These approximations are denoted as parameterizations.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Parameterizations due to computing effort&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;When we consider processes such as &lt;strong&gt;particle formation, growth, and coagulation&lt;/strong&gt; we could consider every particle or even every molecule in a model. However, in real world atmospheric applications we have too much particles than we could consider them individually. Therefore, we need to calculate the growth of particles on the base of some parameters and apply it on (log-normal) particle number/volume/... distributions.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Parameterizations due to missing and condensed information&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Biogenic emissions&lt;/strong&gt; are a nice example. We do not know exactly where which trees and plants are located (and which atmospheric conditions like humidity and temperature prevail). For some regions we know it: e.g. for the city of Hamburg there is a detailed (non-public) tree inventory existing. When we do not have this information and work in a gridded domain (i.e. 10 km x 10 km) we need to make a simplified assumption - such as 10% of the grid cell ground is covered by urban area, 30% by grassland, 10% by desert and 50% by forest (of which 70% are pine trees and 30% other trees). From this information and the average ground level temperature and humidity we need to estimate the amount of various emitted volatile organic compounds. Doing this, is a parameterizations because we over-simplify the actual real world.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;But&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;From my feeling I would describe a process representation in a model as explicit/non-parameterized when it is included according to the best current/state-of-the-art knowledge. In contrast, when it is considerably simplified, I would denote it as a parameterization.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;However&lt;/strong&gt;, when we presented &lt;strong&gt;gas phase chemical processes&lt;/strong&gt; by differential equations - like as it is done in the gas phase chemistry mechanisms of chemistry transport models -, I would not consider it as parameterizations because due to a large number of identical molecules (and the law of large numbers - probably) we do not actually introduce a large error. &lt;/p&gt;&#xA;" OwnerUserId="5594" LastEditorUserId="5594" LastEditDate="2016-09-08T14:27:10.373" LastActivityDate="2016-09-08T14:27:10.373" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8702" PostTypeId="1" CreationDate="2016-09-08T15:44:28.183" Score="4" ViewCount="176" Body="&lt;p&gt;Say a plane moves from 40° North to 40° South, and the plane flies in straight line without considering the Coriolis effect. Will it still reach the destination.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All I mean is whether the deflection caused in the Northern Hemisphere can be compensated for in Southern Hemisphere&lt;/p&gt;&#xA;" OwnerUserId="6572" LastEditorUserId="725" LastEditDate="2016-09-10T09:04:36.477" LastActivityDate="2016-09-12T01:51:50.283" Title="Can Coriolis Effect cancel itself?" Tags="|earth-rotation|coriolis|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8703" PostTypeId="1" CreationDate="2016-09-09T09:02:45.220" Score="2" ViewCount="89" Body="&lt;p&gt;Few months ago I watched a video posted on reddit about climate change and in it there was scene showing glass of water with ice cubes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;They were measuring how long it takes for ice to melt and then after ice is melted how rapidly water warms. My best guest was Guy McPherson or Bill Nye video, not sure about Cowspiricy, but I have now seen I do not know how many and I could not find that scene. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am looking video (scene) that shows how glass full of water stay for 40min+ at the same 1C temperature while ice is there, but as soon as ice melts, temperature of water increases to 25C (room temperature) just in 5 minutes. There was a glass of water with timer and thermometer, displaying melting ice and rise of temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically it makes a point that without ice water warms more rapid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there anyone there that has maybe seen the video please can you send me the link or tell me where it was? &lt;/p&gt;&#xA;" OwnerUserId="6577" LastActivityDate="2016-09-09T11:30:22.213" Title="Please could you help me finding global warming video with ice melting in glass time messurment scene?" Tags="|climate-change|water|ice|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8704" PostTypeId="5" CreationDate="2016-09-09T10:51:47.597" Score="0" Body="&lt;p&gt;While the load of chemical species in atmosphere has exceeded the limits of its capability, there will be environmental issue causing disease and environmental damage. The source of air pollutants(SO2, NOx, VOC, etc)  conclude both nature(volcano, desert, wild fire, etc) and anthropogenic(industry, domestic, vehicle, etc). Emission, transport and chemical reaction are three fundamental process related to air pollution.&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="5214" LastEditDate="2016-09-09T12:58:41.023" LastActivityDate="2016-09-09T12:58:41.023" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8705" PostTypeId="4" CreationDate="2016-09-09T10:51:47.597" Score="0" Body="Air pollution is the introduction of particulates, biological molecules, or other harmful materials into Earth's atmosphere, causing diseases, allergies, death to humans, damage to other living organisms such as animals and food crops, or the natural or built environment." OwnerUserId="5214" LastEditorUserId="5214" LastEditDate="2016-09-09T12:58:52.547" LastActivityDate="2016-09-09T12:58:52.547" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8706" PostTypeId="2" ParentId="8703" CreationDate="2016-09-09T11:30:22.213" Score="1" Body="&lt;p&gt;This is probably not the specific video you are looking for, but here is one:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The video &lt;a href=&quot;https://www.youtube.com/watch?v=0wEJMtCcTfo&quot; rel=&quot;nofollow&quot;&gt;Latent heat of fusion&lt;/a&gt; shows the effect that you mean in a real world situation where the water is not mixed well.&lt;br /&gt;&#xA;The video &lt;a href=&quot;https://www.youtube.com/watch?v=zk4vhD2X4Ew&quot; rel=&quot;nofollow&quot;&gt;Determination of Melting Point of Ice&lt;/a&gt; shows it under more controlled conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The video &lt;a href=&quot;https://www.youtube.com/watch?v=STURzRg7LDQ&quot; rel=&quot;nofollow&quot;&gt;Heat in changes of state&lt;/a&gt; explains it with a graph.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The video &lt;a href=&quot;https://www.youtube.com/watch?v=0n5iL3Gg_mg&quot; rel=&quot;nofollow&quot;&gt;Energy required to melt ice and warm the water&lt;/a&gt; gives you an actual calculation example and shows the energy involved in melting ice vs. heating water.&lt;/p&gt;&#xA;" OwnerUserId="595" LastActivityDate="2016-09-09T11:30:22.213" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8707" PostTypeId="2" ParentId="8692" CreationDate="2016-09-09T11:40:05.023" Score="1" Body="&lt;p&gt;Folk and Ward (1957) were the ones who created a measure of sorting using graphical moments of particle size distribution based upon φ values obtained graphically from the cumulative frequency curve at specific percentile levels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I wasn't aware that negative values were possible based on the equation, but I am not up on my sedimentology..&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming your value is correct, it would signify extremely well sorted material:  the Inclusive Graphic Standard Deviation (Folk and Ward, 1957) has a phi range of &amp;lt;0.3 (extremely well sorted) to &gt;3.0 (extremely poorly sorted).&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Folk, Robert L., and William C. Ward. &quot;Brazos River bar: a study in the significance of grain size parameters.&quot; Journal of Sedimentary Research 27.1 (1957).&lt;/p&gt;&#xA;" OwnerUserId="6480" LastActivityDate="2016-09-09T11:40:05.023" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8708" PostTypeId="1" CreationDate="2016-09-09T12:04:59.293" Score="11" ViewCount="374" Body="&lt;p&gt;Climate and chemical transport models all need input files including meteorology data, emission inventory, surface data (e.g. land use type) to initialize the simulation field. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take the case of WRF for regional meteorology data. I always use the 1 degree x 1 degree &lt;a href=&quot;http://rda.ucar.edu/datasets/ds083.2/&quot; rel=&quot;nofollow&quot;&gt;NCEP FNL analysis&lt;/a&gt; data in grib2 format as the model-driven data supporting the boundary and initial information every 6 hours.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, I find that the ECMWF interim reanalysis data with spatial 0.25 degree x 0.25 degree can also be used as the WRF input. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, I'm wondering does finer input data induce better model performance? How much can be improved if the answer is true?    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have thought out some pros of finer input file (in both spatial and temporal scale):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;pros&lt;/strong&gt;: (1) finer input field means the physical process of smaller scale(e.g turbulent transport of water) can be depicted better in some extent; (2) finer temporal variation of chemical species can emulate the real emission process better(e.g, emission related to traffic in a day). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any &lt;strong&gt;cons&lt;/strong&gt; that come with the performance improvement except the computational cost?    &lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="5214" LastEditDate="2016-09-10T09:24:03.690" LastActivityDate="2016-09-14T13:35:50.913" Title="Does finer input data lead to a better model accuracy?" Tags="|meteorology|models|atmosphere-modelling|wrf|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8709" PostTypeId="1" AcceptedAnswerId="8713" CreationDate="2016-09-09T17:53:59.107" Score="6" ViewCount="1829" Body="&lt;p&gt;I know that the passage of a cold front affects local conditions by decreasing the temperature and shifting the winds. Some precipitation could happen as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How do software that analyze weather station data identify a cold front passage? Is there a certain change in temperature, wind, pressure, or other variable that allows the software to identify a front? &lt;/p&gt;&#xA;" OwnerUserId="6444" LastEditorUserId="543" LastEditDate="2016-12-17T06:16:42.857" LastActivityDate="2016-12-17T06:16:42.857" Title="How to locally identify a cold front passage?" Tags="|meteorology|atmosphere|earth-observation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8710" PostTypeId="2" ParentId="8708" CreationDate="2016-09-09T18:46:01.997" Score="9" Body="&lt;p&gt;My experience with the WRF is in tropical cyclone simulation, but here are some things to consider:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Smaller scale information might already be resolved in your higher resolution initial conditions, improving the spin-up time of effects you are trying to model&lt;/li&gt;&#xA;&lt;li&gt;I believe the ECMWF resolution has been statistically downscaled from a 0.75 degree dataset, I might be wrong on that one though. That would mean that your 0.25 degree is just some interpolated data &lt;/li&gt;&#xA;&lt;li&gt;Some models perform better than others in specific regions&lt;/li&gt;&#xA;&lt;li&gt;Higher resolution is not better if your parameterization is wrong&lt;/li&gt;&#xA;&lt;li&gt;You can find caveats of specific datasets here: &lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/gridded/&quot; rel=&quot;nofollow&quot;&gt;PSD Gridded Climate Datasets.&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6444" LastEditorUserId="6093" LastEditDate="2016-09-14T13:35:50.913" LastActivityDate="2016-09-14T13:35:50.913" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8712" PostTypeId="2" ParentId="8708" CreationDate="2016-09-10T02:31:30.817" Score="7" Body="&lt;p&gt;Yes, of course finer input data &lt;em&gt;can&lt;/em&gt; lead to better model accuracy, but only if the model's conceptualization is close to the mark. Of the many problems of climatic model misinterpretation, I would emphasize the following:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;a) The implied precision of most climatic modelling output is absurd, so take a long, hard and skeptical look at the data in relation to realistic error bounds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;b) Down-scaled models tend to give an impression of higher accuracy. For the most part, this is illusory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;c) Halve the grid dimension and you require four times as much input data. In reality there usually isn't that much good quality data available, and even if there is (in principle), there usually isn't the manpower capability to process it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;d) Reduce the grid size, and you have to pay much closer attention to the conceptualization. For example, physiographic impacts upon rainfall, land-water ratio, and microclimatic factors become more important.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In my experience of working on AOGCM outputs in East Africa, I found that smaller grids only highlights local climatic discrepancies between model and evidence-based instrumental data. Even with smaller grids, the models totally fail to capture meso-climatic impacts of large lakes, or the steep climatic gradients over a scale of about 100 km. So the message is clear: global climatic models are great for general climatic trends, dubious for rainfall trends, and downright misleading for most small scale climate trend analysis. My worry is that one of leading categories of GCM users, water resources analysts, don't yet seem to have a clear grasp of GCM limitations. There are dangers in treating climatic computer models as a 'magical black box'. There are inherent dangers in gridding the available data realistically (a &lt;em&gt;major&lt;/em&gt; source of error!). And whenever you choose a finer grid size, &lt;em&gt;always&lt;/em&gt; pay very close attention to differences between hind-cast outputs and the actual spread of climatic data on the ground. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2016-09-10T02:41:18.973" LastActivityDate="2016-09-10T02:41:18.973" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8713" PostTypeId="2" ParentId="8709" CreationDate="2016-09-10T16:10:49.833" Score="7" Body="&lt;p&gt;A cold front lies in a trough of low pressure and separates air masses.  As you mention in your question there are differences in temperature and the winds on either side of the front, though these can be subtle depending on latitude and season.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A &quot;classic&quot; (mid-latitude NH) cold frontal passage might be recorded as southerly or southwesterly winds, increasing in in strength, temperatures rising and pressure falling.  As FROPA occurs the pressure will bottom out and start to rise, winds shift to northwesterly or northerly, temperatures start to fall and skies clear.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A &quot;classic&quot; (mid-latitude NH) warm frontal passage might be seen as temperatures stable, calm or weak southerly or easterly winds, high clouds with bases lowering over time and pressure falling.  The FROPA will see pressure at its minimum and starting to rise, winds shifting to southerly and temperature warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The common factors the changes in pressure, wind and temperature and can be used to determine frontal passage.  Look for a pressure minimum, a change in temperature trend and a shift in wind.  A cold frontal will also generally bring drier air, and a warm front humid air, so this can also be used.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a meteogram from SLC:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/c3fkW.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/c3fkW.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this plot, cold frontal passage occurs around 7Z, marked by a minimum pressure trending upward, dropping temperatures and dew points, winds shifting to northerly and skies starting to clear once the precipitation ends.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Individual frontal passages will be different in exact details, but these general set of trends should help you out.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2016-09-10T16:10:49.833" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8714" PostTypeId="1" CreationDate="2016-09-10T17:45:18.380" Score="5" ViewCount="95" Body="&lt;p&gt;The concept of subduction seismogenic zone, where megathrust seisms occur in a layer between an upper and a lower limit is well documented in the 1990/early 2000 literature : &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some example :&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Pacheco, J. F., Sykes, L. R., &amp;amp; Scholz, C. H. (1993), Nature of seismic coupling along simple plate boundaries of the subduction type. Journal of Geophysical Research: Solid Earth, 98(B8), 14133–14159. &lt;a href=&quot;http://doi.org/10.1029/93JB00349&quot;&gt;http://doi.org/10.1029/93JB00349&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Hyndman, R. D., Yamano, M. and Oleskevich, D. A. (1997), The seismogenic zone of subduction thrust faults. Island Arc, 6: 244–260. doi:10.1111/j.1440-1738.1997.tb00175.x&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;But is this concept still accurate and used in the scientific community now ? i.e. after the megaseisms of Indonesia in 2004 and Tohoku in 2011, where huge areas break up to the surface and generate big megatsunamis. More exactly, is the notion of upper limit still making sense and, if yes, what are the currently-supposed parameters which control it ?&lt;/p&gt;&#xA;" OwnerUserId="6585" LastActivityDate="2016-10-04T04:32:48.450" Title="Is the concept of seismogenic zone still relevant after the 2011 Japan earthquake?" Tags="|seismology|earthquakes|geodynamics|tsunami|subduction|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8715" PostTypeId="2" ParentId="8135" CreationDate="2016-09-10T22:29:09.350" Score="-3" Body="&lt;p&gt;Most estimates of global surface temperature &quot;anomaly&quot; come from NASA GISS network database &lt;a href=&quot;http://data.giss.nasa.gov/gistemp/station_data/&quot; rel=&quot;nofollow&quot;&gt;http://data.giss.nasa.gov/gistemp/station_data/&lt;/a&gt; .&#xA;There are some stations that show cooling trend over 100-year-long history of observations, as shown here:&#xA;&lt;a href=&quot;https://stevemosher.wordpress.com/2010/09/29/needs-chec/&quot; rel=&quot;nofollow&quot;&gt;https://stevemosher.wordpress.com/2010/09/29/needs-chec/&lt;/a&gt; &#xA;This is considered as a normal &quot;bell-curve&quot; distribution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, as it was noted in old discussions,  there are several examples where the OPPOSITE trend happens on ADJACENT stations that are only 50 km apart. This means that the spatial distribution of surface stations is insufficient to reconstruct characteristics of temperature field (averages, etc.), because the spatial sampling does not satisfy criteria for Nyquist-Shannon Sampling Theorem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get the sampling right, the station site locations must be at least half of 50km, or about 25 km apart around the globe. With Earth surface having 5×10&lt;sup&gt;8&lt;/sup&gt; km&lt;sup&gt;2&lt;/sup&gt;, the 25×25 km grid should have about 800,000 stations. Given 30% dry land, there should be about 240,000 surface stations to have any scientifically reasonable estimation of trends. This is the most conservative estimations for necessary amount of data to collect.The GISS network has less than 6,000 stations world-wide, which means that the data are undersampled by a factor of 40.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If one has a field so vastly undersampled, selective treatment of datasets could result in anything, which explains contradictions in various estimates.&lt;/p&gt;&#xA;" OwnerUserId="6584" LastEditorUserId="725" LastEditDate="2016-09-14T03:54:15.893" LastActivityDate="2016-09-14T03:54:15.893" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="8716" PostTypeId="1" CreationDate="2016-09-11T01:09:28.107" Score="3" ViewCount="25932" Body="&lt;p&gt;How does elevation affect the amount of rainfall received? Does elevation affect precipitation?&lt;/p&gt;&#xA;" OwnerUserId="6517" LastEditorDisplayName="user1161" LastEditDate="2017-07-02T02:54:11.107" LastActivityDate="2019-06-19T01:45:27.360" Title="How does elevation affect the amount of rainfall received?" Tags="|precipitation|rainfall|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8717" PostTypeId="2" ParentId="8716" CreationDate="2016-09-11T04:22:36.613" Score="4" Body="&lt;p&gt;Elevation affects temperature which affects the amount of rain. Most raingauges around the world are within a few hundred metres of sea-level, i.e the range in which most people live. Within this range the rainfall-elevation relationship often appears to be linear. However, as the temperature gets cooler with altitude, the maximum precipitable moisture decreases drastically, so the rainfall-altitude curve reflexes back upon itself, so that there is an elevation of maximum precipitation ('EMP'). This variation variies with several factors, such as continentality, 'tropicality', aspect, rain shadow and barrier effect. Some examples of the EMP, are (in metres): Tajikistan 3800,&#xA;Alberta Canada 2360, European Alps, 2250, NW Pakistan1500, Oman 1400 to 2200, Kilimanjaro Tanzania 1500, and Hawaii 900. In the case of polar regions the EMP is ground level because the rainfall-altitude relationship is nearly always negative. Above the EMP the rainfall decreases rapidly with altitude, which is why high mountainous regions are essentially deserts. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wherever there is significant relief in a catchment, the first step is to determine whether the catchment is all below the EMP. The second step is to process the historic record to see if a second order, or even third order rainfall altitude regression is a significant improvement upon 'linear'. If you want further refinement the seasonal rainfalls, or rainfalls from different directions, often have markedly differing rainfall-altitude relationships. If you want to go the whole hog, and be scientific about it, then the rainfall approximates a multi-variate solution, with components of &#xA;altitude, altitude squared, aspect, regional trend, rain shadow and barrier effect. This can be solved as an equation of the form: $$R = aH + BH^{2} + cA + dT + eS +f'BE'$$&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="6465" LastEditDate="2017-07-03T19:49:50.450" LastActivityDate="2017-07-03T19:49:50.450" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8718" PostTypeId="1" CreationDate="2016-09-11T10:41:49.077" Score="3" ViewCount="733" Body="&lt;p&gt;Most people may believe that oil comes from dead plants and animals, but there are alternative theories that are known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Abiogenic_petroleum_origin&quot; rel=&quot;nofollow&quot;&gt;Abiogenic Petroleum Origin&lt;/a&gt;. If oil in generated in this manner it could mean we could find oil on other planets or moons as well.&lt;/p&gt;&#xA;" OwnerUserId="6588" LastEditorUserId="6093" LastEditDate="2016-09-12T05:20:09.743" LastActivityDate="2016-09-13T21:53:34.043" Title="What is the origin of oil?" Tags="|geophysics|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8719" PostTypeId="2" ParentId="8702" CreationDate="2016-09-11T12:29:35.830" Score="2" Body="&lt;p&gt;In an idealised scenario (ie where the plane is flying due north or south at a and there are no other perturbations to its course apart from the Coriolis effect), yes. And I guess it would be the most efficient course too!&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2016-09-12T01:51:50.283" LastActivityDate="2016-09-12T01:51:50.283" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8720" PostTypeId="2" ParentId="8718" CreationDate="2016-09-11T13:46:25.040" Score="9" Body="&lt;p&gt;As far as we can tell, almost all crude oil (petroleum) is biogenic, and specifically comes from marine organisms. That's the only theory that is supported by the geological record, by the thermodynamics, &lt;strong&gt;and&lt;/strong&gt; by what we know of the biology and the chemistry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's not to exclude the possibility of abiogenic petroleum: indeed, we &lt;strong&gt;know&lt;/strong&gt; that abiogenic liquid hydrocarbons are possible, because we can synthesise them ourselves. So finding hydrocarbons that &lt;em&gt;cannot&lt;/em&gt; be biogenic does &lt;strong&gt;not&lt;/strong&gt; show that most fossil fuels are abiogenic: it merely shows that some abiogenic hydrocarbons exist.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the quack theory, popular in Soviet Russia and with other fringe pseudo-scientists, is that almost all oil discovered in the ground comes from abiogenic sources. Geoff Glasby looked at how the pseudo-science came about, in his article &lt;a href=&quot;http://static.scribd.com/docs/j79lhbgbjbqrb.pdf&quot;&gt;Abiogenic Origin of Hydrocarbons: An Historical Overview&lt;/a&gt; (Resource Geology, vol. 56, no. 1, 85–98, 2006) &lt;a href=&quot;http://dx.doi.org/10.1111/j.1751-3928.2006.tb00271.x&quot;&gt;DOI:10.1111/j.1751-3928.2006.tb00271.x&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="100" LastEditDate="2016-09-11T18:03:16.480" LastActivityDate="2016-09-11T18:03:16.480" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8721" PostTypeId="2" ParentId="8718" CreationDate="2016-09-12T01:13:04.310" Score="3" Body="&lt;p&gt;Dead macro-organisms, plants and animals, are not necessary to form oil. For example consider oil from the Pre-Cambrian siltstones of Oman, which formed long before the evolution of land animals or plants. On the other hand, EnergyNumbers is correct, that the hypothesis of abiogenic origin of oil, proposed by creationists, etc., is completely defunct. There is plenty of abiogenic hydrogen in the Earth, such as released through the process of serpentinization, but it takes more than hydrogen to make oil. In fact there are three requirements: kerogen, temperature and time. The kerogen comes in many forms, being derived mainly from marine and lacustrine microbiota, and also from higher land plants. A  small fraction also comes from weathering of polycyclic aromatic hydrocarbons. These provide the complex polymers, in some ways similar to the tannin in your tea, from which the more complex oil molecules are formed. Oil is a complex cocktail of compounds, of which I would cite in particular the C27-C29 steranes as being indicative of the oil's age. It takes hundreds of millions of years under warm pressurized conditions for the 'C29' type of oil to evolve. I cannot envisage any conditions in which these compounds could evolve from simple methane-type precursors. That's not to say it is impossible (maybe my limited imagination?), but it's very improbable. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for oil on other planets, without life, first define what you mean by 'oil'. Simple organics are widespread, both in the Solar System and beyond. More complex organics probably require life to evolve, especially in the cold conditions of moons in the outer Solar System. But who knows what exists in the hidden ocean beneath the icy surface of Europa? I would be surprised to find 'Earth-like' oils in this ocean, but the evolution of simpler oils in this environment would seem eminently plausible.   &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-09-12T01:13:04.310" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8722" PostTypeId="2" ParentId="8637" CreationDate="2016-09-12T02:27:43.260" Score="5" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Is the ratio of IC to CG lightning relevant?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Yes. Primarily, severe storms tend to have very few cloud-to-ground (CG) strikes. Thus, the ratio of IC:CG is likely going to be very high.&lt;sup&gt;1 2&lt;/sup&gt; However, some severe storms do produce a significant amount of positive CG strikes. They would still have a high IC:CG ratio, but they would distinguish themselves by having more positive CG strikes. However, both of these types -- low-CG and some-positive-CG -- are potentially severe.&lt;sup&gt;2&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;It is important to note that the amount of CG strikes can be dependent both on where in the lifecycle a storm is, and the physical location of a storm (CG characteristics appear to be region-dependent). In tornadic supercells, the total amount of lightning seems to decrease during tornadogenesis, and the CG rate appears to increase after the tornadic stage of that supercell ends.&lt;sup&gt;3&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;There doesn't appear to be any existing literature on amplitude as a measure of severity. Perhaps, through this work, you might be able to identify whether this is an area which should be studied further.&lt;/p&gt;&#xA;&lt;h3&gt;References&lt;/h3&gt;&#xA;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt; Donald R. MacGorman, Donald W. Burgess, Vladislav Mazur, W. David Rust, William L. Taylor, and Brenda C. Johnson, 1989: &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0469%281989%29046%3C0221%3ALRRTTS%3E2.0.CO%3B2&quot; rel=&quot;noreferrer&quot;&gt;Lightning Rates Relative to Tornadic Storm Evolution on 22 May 1981.&lt;/a&gt; &lt;em&gt;J. Atmos. Sci.&lt;/em&gt;, &lt;strong&gt;46&lt;/strong&gt;, 221–251, doi: 10.1175/1520-0469(1989)046&amp;lt;0221:LRRTTS&amp;gt;2.0.CO;2.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;2&lt;/sup&gt; Timothy J. Lang and Steven A. Rutledge, 2002: &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0493%282002%29130%3C2492%3ARBCSKP%3E2.0.CO%3B2&quot; rel=&quot;noreferrer&quot;&gt;Relationships between Convective Storm Kinematics, Precipitation, and Lightning.&lt;/a&gt; &lt;em&gt;Mon. Wea. Rev&lt;/em&gt;., &lt;strong&gt;130&lt;/strong&gt;, 2492–2506, doi: 10.1175/1520-0493(2002)130&amp;lt;2492:RBCSKP&amp;gt;2.0.CO;2.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;3&lt;/sup&gt; Scott M. Steiger, Richard E. Orville, and Lawrence D. Carey, 2007: &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/MWR3472.1&quot; rel=&quot;noreferrer&quot;&gt;Total Lightning Signatures of Thunderstorm Intensity over North Texas. Part I: Supercells.&lt;/a&gt; &lt;em&gt;Mon. Wea. Rev.&lt;/em&gt;, &lt;strong&gt;135&lt;/strong&gt;, 3281–3302, doi: 10.1175/MWR3472.1.&lt;/p&gt;&#xA;&lt;h3&gt;Further Reading&lt;/h3&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Lawrence D. Carey, Steven A. Rutledge, and Walter A. Petersen, 2003: &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0493%282003%29131%3C1211%3ATRBSSR%3E2.0.CO%3B2&quot; rel=&quot;noreferrer&quot;&gt;The Relationship between Severe Storm Reports and Cloud-to-Ground Lightning Polarity in the Contiguous United States from 1989 to 1998.&lt;/a&gt; &lt;em&gt;Mon. Wea. Rev.&lt;/em&gt;, &lt;strong&gt;131&lt;/strong&gt;, 1211–1228, doi: 10.1175/1520-0493(2003)131&amp;lt;1211:TRBSSR&amp;gt;2.0.CO;2.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Yeung, Linus HY, E. S. T. Lai, and S. K. S. Chiu. &lt;a href=&quot;https://ams.confex.com/ams/pdfpapers/123157.pdf&quot; rel=&quot;noreferrer&quot;&gt;&amp;quot;Lightning Initiation and Intensity Nowcasting Based on Isothermal Radar Reflectivity-A Conceptual Model.&amp;quot;&lt;/a&gt; The 33rd International Conference on Radar Meteorology. 2007.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;C. Emersic, P. L. Heinselman, D. R. MacGorman, and E. C. Bruning, 2011: &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/2010MWR3574.1&quot; rel=&quot;noreferrer&quot;&gt;Lightning Activity in a Hail-Producing Storm Observed with Phased-Array Radar.&lt;/a&gt; &lt;em&gt;Mon. Wea. Rev.&lt;/em&gt;, &lt;strong&gt;139&lt;/strong&gt;, 1809–1825, doi: 10.1175/2010MWR3574.1.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="20" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-09-12T02:27:43.260" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8726" PostTypeId="1" CreationDate="2016-09-12T19:37:42.643" Score="6" ViewCount="333" Body="&lt;p&gt;On 11 sep 2016, the Australian Herald Sun placed an opinion piece by Andrew Bolt titled &lt;a href=&quot;http://www.heraldsun.com.au/blogs/andrew-bolt/drowning-in-cash-pacific-islands-love-this-scare/news-story/c92f2153c1d159cdf4cf7a4a604c8362&quot; rel=&quot;nofollow&quot;&gt;Drowning in cash: Pacific islands love this scare&lt;/a&gt;&lt;sup&gt;*&lt;/sup&gt; about the $300 million&lt;sup&gt;**&lt;/sup&gt; financial aid pledged by the Australian Prime Minister, Malcolm Turnbull, at a Pacific leaders’ forum in Micronesia last week (I guess that's &lt;a href=&quot;https://pacifictradeinvest.com/events/47th-pacific-islands-forum-leaders-meetings/&quot; rel=&quot;nofollow&quot;&gt;this meeting&lt;/a&gt;), to help the Pacific “manage climate change and improve disaster resilience&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bolt's critique is that these islands do not actually face much danger:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The scare that these islands risk drowning as man-made warming melts our ice caps is wildly exaggerated.&lt;br /&gt;&#xA;  Professor Paul Kench, an Auckland University coastal geomorphologist, along with Australian scientists, has studied more than 600 coral reef islands.&lt;br /&gt;&#xA;  His findings: about 40 per cent have actually grown in size. Another 40 per cent stayed stable, and just 20 per cent have shrunk.&lt;br /&gt;&#xA;  Much of that is because coral islands, essentially living things, grow with rising seas, as well as with sand washed up by the waves.&lt;br /&gt;&#xA;  What’s more, populated islands can reclaim land.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.env.auckland.ac.nz/people/p-kench&quot; rel=&quot;nofollow&quot;&gt;Paul Kench's page at the University of Auckland&lt;/a&gt; lists several of his publications, and maybe the blog post refers to this one: &#xA;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/wcc.350/abstract;jsessionid=AE21F350261FC08E7FDDA7AAD49E5183.f01t01&quot; rel=&quot;nofollow&quot;&gt;Destruction or persistence of coral atoll islands in the face of 20th and 21st century sea-level rise?&lt;/a&gt;&lt;br /&gt;&#xA;From the abstract:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Here, we analyze the physical changes in over 200 islands on 12 atolls in the central and western Pacific in the past few decades when sea level in the region increased at rates three to four times the global average. Results show little evidence of heightened erosion or reduction in island size. Instead island shores have adjusted their position and morphology in response to human impacts such as seawall construction and to variations in climate–ocean processes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The article is behind a paywall, so I cannot look at the actual study - the abstract does not mention anything about coral growth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as I know, sea level rise is going to be much faster than coral can grow, plus we have the complication factor of reduced grow (or actual coral death) because of rising sea water acidity and temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But it's still an intriguing question: &lt;strong&gt;Could there be a hint of truth in this, that coral growth could keep up with sea level rise?&lt;/strong&gt;&lt;br /&gt;&#xA;Maybe with a little help from us?&lt;br /&gt;&#xA;Has this been investigated?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;* You may have trouble following this link directly. In that case go to the start page, Andrew Bolt's blog, and look up the article there.&lt;/sup&gt;&lt;br /&gt;&#xA;&lt;sup&gt;** Australian dollars, I assume. That would be US$ 227 million&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="595" LastEditorUserId="595" LastEditDate="2016-09-13T07:12:09.180" LastActivityDate="2016-09-13T07:12:09.180" Title="Coral growth keeping up with sea level rise?" Tags="|climate-change|sea-level|pacific|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8727" PostTypeId="1" CreationDate="2016-09-12T20:59:41.373" Score="4" ViewCount="169" Body="&lt;p&gt;&lt;a href=&quot;http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2796.html&quot; rel=&quot;noreferrer&quot;&gt;Ide et al. (2016)&lt;/a&gt; suggest that earthquakes (especially those of high magnitudes) are more probable during periods of high tidal stress (during full and new moons). While they show a comprehensive dataset and analysis to corroborate their claims, it contradicts previous findings (e.g., &lt;a href=&quot;http://srl.geoscienceworld.org/content/75/5/607&quot; rel=&quot;noreferrer&quot;&gt;Kennedy et al., 2004)&lt;/a&gt;. Their argument claiming that tides trigger the transformation from small fracture to the large rupture associated with large earthquakes seems counter-intuitive to me. Wouldn't it make more sense for the relatively small changes associated with the tidal stress to be more related to smaller earthquakes?&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2016-09-14T05:10:36.277" Title="Relationship between tides and earthquakes" Tags="|seismology|earthquakes|tectonics|tides|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8728" PostTypeId="2" ParentId="8708" CreationDate="2016-09-12T21:50:42.893" Score="0" Body="&lt;p&gt;To begin, climatology does not have real 25km x 25km data, since they have only about 6000 meteostations, while the 25x25 grid on dry land amounts to 240,000 stations. Artificial make-up of this kind of data must use variety of assumptions that might be not necessary true or coherent. Feeding a model with goofy data would accomplish nothing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second, finer input data do nothing if the model does not resolve dynamic patterns of the same scale. Unless you see a model that correctly reproduces main details of global atmospheric circulation (I mean just crude topology of vortices-hurricanes and their average frequency), fine input is meaningless. More, a good correct model should start with any realistic and non-detailed data, and develop a stable realistic trajectory with realistic means. Climate and transport data should not need any &quot;input&quot;, the model must generate the data on its own.&lt;/p&gt;&#xA;" OwnerUserId="6584" LastActivityDate="2016-09-12T21:50:42.893" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8729" PostTypeId="2" ParentId="8726" CreationDate="2016-09-13T02:23:58.000" Score="9" Body="&lt;p&gt;I have worked as a climate-change specialist in many countries including those with coral atolls, such as the Maldives, Solomon Islands and Samoa. I have analysed, at first hand, both the the tide-gauge and satellite-based rates of sea level rise. Notwithstanding the non-scientific writings of that well-known journalist, Andrew Bolt, the demonstrable truth is that ocean acidification is real and unstopable for the foreseeable future. The sea surface is warming faster than expected a decade ago, and the rate of sea level rise is accelerating. In the southwest Pacific, which is particularly prone to El Nino intensification, these affects are even more alarming. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I point out that Bolt has zero scientific credentials, has never done any climate research, and is only able to make a living as a climate-skeptic writer because many Australians are, by nature, predisposed to enjoy 'contrary' arguments, irrespective of the science. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Much research has gone into coral growth over the last decade, particularly in peri-Australian waters. Current findings are that, &lt;em&gt;under optimum conditions&lt;/em&gt;, the fastest growing corals can indeed grow fast enough to keep up with the current rates of sea level rise. However, this cannot continue indefinitely. The reef is a total ecosystem, of fast and slow growing corals, bryozoa, etc., which has an aggregate rate of growth of less than the rise of sea level. Fast growing pioneering corals eventually collapse if left to continue growing ahead of the rest of the biome. Note also the phrase &quot;under optimum conditions&quot;. As Jan Doggen rightly points out, sea-surface warming beyond the optimum thermo-tolerance, acidification, and water pollution are all serious stress factors. Between them one can say that, apart from deep-water corals, there is hardly a coral reef on the planet that isn't  suffering from sub-optimal growth conditions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is another somewhat unexpected threat to corals: ordinary sun-cream from holidaymakers swimming near reefs. The common sun-cream component of oxy-benzone (present in most sun-creams) is toxic to corals at only about 60 parts per trillion. Globally, an estimated 10,000 tonnes of sun-screen ends up in the oceans, near corals, every year. This has a noticeable negative impact on the reef.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Taken altogether, this quadruple whammy bodes ill for the world's coral reefs. When the reefs die, and sea level rises there will be nothing to stop sub-tropical waves eroding the very land that some Pacific Islanders live on. Even islands with higher elevations still have fringing reefs. They are all in trouble, because sea level rise and higher erosion rates will force a retreat from the coast (hopefully planned), with massive social, environmental and economic disruption. So yes, they are absolutely justified in getting agitated about reef degradation!&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="595" LastEditDate="2016-09-13T07:09:25.763" LastActivityDate="2016-09-13T07:09:25.763" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8730" PostTypeId="2" ParentId="825" CreationDate="2016-09-13T03:48:21.240" Score="4" Body="&lt;p&gt;Actual climatologist here.&lt;/p&gt;&#xA;&lt;p&gt;The earth would be covered in ice. That is the only answer you need.&lt;/p&gt;&#xA;&lt;p&gt;Others attempting to calculate a change in global temperature seem to lack a basic understanding of how the global system functions (greenhouse gases are only one aspect that controls global temperature).&lt;/p&gt;&#xA;&lt;p&gt;Those who seem to think it would be fried or barren neglect to understand the difference between the atmosphere and earth's protective magnetic field. If we had no magnetic field, in addition to many, many other problems, our planet would fry regardless of the presence and chemical composition of an atmosphere. Without an atmosphere and greenhouse gases, however, the planet would freeze. With too many greenhouse gases under other optimal climate conditions, it would look like Venus.&lt;/p&gt;&#xA;&lt;p&gt;Please don't trust someone who gets their answers from Wikipedia. If you prefer more mass-media resources, you can cite the following articles:&#xA;&lt;a href=&quot;https://www.nationalgeographic.com/science/article/100304-snowball-earth-ice-global-warming&quot; rel=&quot;nofollow noreferrer&quot;&gt;&amp;quot;Snowball Earth&amp;quot; Confirmed: Ice Covered Equator&lt;/a&gt; (National Geographic, 6 Mar 2010)&lt;/p&gt;&#xA;&lt;p&gt;Alternatively, you can use more science-based research:&#xA;&lt;a href=&quot;http://www.giss.nasa.gov/research/briefs/sohl_01/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Did the Snowball Earth Have a Slushball Ocean?&lt;/a&gt; (NASA GIS, Oct 2002)&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;No atmosphere = Snowball earth.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6594" LastEditorUserId="27654" LastEditDate="2022-09-18T22:46:26.130" LastActivityDate="2022-09-18T22:46:26.130" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="8731" PostTypeId="2" ParentId="8718" CreationDate="2016-09-13T03:55:17.567" Score="-1" Body="&lt;p&gt;Actual environmental scientist here. Crude oil and other similar &quot;fossil fuels&quot; are the result of organic materials held at intense pressures for millions of years. That is the only theory accepted by modern scientists outside of the Ukraine. There is no other theory, because no other hypothesis has been supported with the kind of evidence necessary to even consider mentioning it in conversation. Anything that says otherwise is pseudo-science. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oil = organic materials&lt;/p&gt;&#xA;" OwnerUserId="6594" LastActivityDate="2016-09-13T03:55:17.567" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8732" PostTypeId="2" ParentId="5063" CreationDate="2016-09-13T04:14:42.430" Score="-3" Body="&lt;p&gt;This falls under the basic principles of physics - the higher the amplitude, the more energy. The ocean is the material that is being used, but think of it as an isolated wave of energy. Under any application - light, sound, etc - the higher the amplitude a/o frequency, the more energy. More energy = more speed. &lt;/p&gt;&#xA;" OwnerUserId="6594" LastActivityDate="2016-09-13T04:14:42.430" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8733" PostTypeId="2" ParentId="1091" CreationDate="2016-09-13T04:19:23.417" Score="1" Body="&lt;p&gt;Are you referring to mid-latitude cyclones, or a different synoptic weather event?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Baroclinicity is one factor of synoptic climatology in the mid-latitudes, but it's hardly the only one. Since meteorologists are moving away from traditional forecasting parameters and heading toward a more radar-focused and statistical inference model, it won't have an impact on the &quot;predictability&quot; of synoptic weather. Remember, our advances in science may be the only thing outpacing climate change, and that's a damn good thing. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One more thing: Psychics &lt;em&gt;predict&lt;/em&gt;, scientists &lt;em&gt;project&lt;/em&gt;. &lt;/p&gt;&#xA;" OwnerUserId="6594" LastActivityDate="2016-09-13T04:19:23.417" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8736" PostTypeId="2" ParentId="8251" CreationDate="2016-09-13T19:14:01.847" Score="0" Body="&lt;p&gt;I haven't programmed in MATLAB in quite a while, but I remember doing some Hovmoller diagrams during my graduate studies. I just looked at my old code, and I used the function &lt;code&gt;contourf&lt;/code&gt;, where my input was a 2D matrix of my data (row-wise was radius, column-wise was time).&lt;/p&gt;&#xA;" OwnerUserId="6444" LastActivityDate="2016-09-13T19:14:01.847" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8737" PostTypeId="2" ParentId="8718" CreationDate="2016-09-13T21:36:42.650" Score="0" Body="&lt;p&gt;So far the science has reached the following conclusion (from &lt;a href=&quot;http://en.cnki.com.cn/Article_en/CJFDTOTAL-SYXB200106001.htm&quot; rel=&quot;nofollow&quot;&gt;this report&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;“Extensive scientific research and practice have proven that a relatively large percentage of hydrocarbons, especially oil, are generated organically. However, this does not rule out the possibility that another large proportion of hydrocarbons, gas in particular, may be of abiogenic origin.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, oil exploration on planets and moons is a way far reaching proposition. &lt;/p&gt;&#xA;" OwnerUserId="6584" LastEditorUserId="6584" LastEditDate="2016-09-13T21:53:34.043" LastActivityDate="2016-09-13T21:53:34.043" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8738" PostTypeId="2" ParentId="8251" CreationDate="2016-09-14T01:06:08.537" Score="2" Body="&lt;p&gt;Here is an example using &lt;a href=&quot;http://www.mathworks.com/help/matlab/ref/contourf.html&quot; rel=&quot;nofollow&quot;&gt;contourf&lt;/a&gt;. The trick is in sampling the 3D arrays appropriately:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;    x=linspace(0,pi,20);&#xA;y=linspace(0,pi,10);&#xA;t=0:10:120;&#xA;[X3d,Y3d,T3d]=meshgrid(x,y,t);&#xA;[X2d,T2dx]=meshgrid(x,t);&#xA;[Y2d,T2dy]=meshgrid(y,t);&#xA;&#xA;dat3d=7*sin(X3d)+5*cos(Y3d)+T3d/max(T3d(:))+rand(size(X3d));&#xA;dat2dx=7*sin(X2d)+5*cos(y(5))+T2dx/max(T2dx(:))+rand(size(X2d)); % at y(5)&#xA;dat2dy=7*sin(x(12))+5*cos(Y2d)+T2dy/max(T2dy(:))+rand(size(Y2d));  % at x(12)&#xA;%%&#xA;figure(1);clf&#xA;contourf(X2d,T2dx,dat2dx);&#xA;shading flat; colorbar&#xA;ylabel('Time (days)')&#xA;xlabel('X distance (km)')&#xA;%%&#xA;figure(2);clf&#xA;contourf(Y2d,T2dy,dat2dy);&#xA;shading flat; colorbar&#xA;ylabel('Time (days)')&#xA;xlabel('Y distance (km)')&#xA;%%&#xA;figure(3);clf&#xA;subplot(221)&#xA;contourf(squeeze(X3d(5,:,:)),squeeze(T3d(5,:,:)),squeeze(dat3d(5,:,:)));&#xA;shading flat; colorbar&#xA;ylabel('Time (days)'); xlabel('X distance (km)')&#xA;title('Hovmoller at y(5)')&#xA;subplot(222)&#xA;contourf(squeeze(Y3d(:,12,:)),squeeze(T3d(:,12,:)),squeeze(dat3d(:,12,:)));&#xA;shading flat; colorbar&#xA;ylabel('Time (days)'); xlabel('Y distance (km)')&#xA;title('Hovmoller at x(12)')&#xA;subplot(223)&#xA;contourf(squeeze(X3d(8,:,:)),squeeze(T3d(8,:,:)),squeeze(dat3d(8,:,:)));&#xA;shading flat; colorbar&#xA;ylabel('Time (days)'); xlabel('X distance (km)')&#xA;title('Hovmoller at y(8)')&#xA;subplot(224)&#xA;contourf(squeeze(Y3d(:,17,:)),squeeze(T3d(:,17,:)),squeeze(dat3d(:,17,:)));&#xA;shading flat; colorbar&#xA;ylabel('Time (days)'); xlabel('Y distance (km)')&#xA;title('Hovmoller at x(17)')&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2016-09-14T01:43:01.747" LastActivityDate="2016-09-14T01:43:01.747" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8739" PostTypeId="2" ParentId="8727" CreationDate="2016-09-14T05:10:36.277" Score="5" Body="&lt;p&gt;I don't find Ide et al's recent paper to be very convincing. They only studied three earthquakes - hardly a statistically representative sample. There are millions of earthquakes on record, and hundreds of really big ones, of more than about MM 7.0, so there is plenty of scope for a more rigorous study. They occur at all phases of the tides. Some have claimed a weak correlation between tidal maxima and earthquake occurrence, but these are only just detectable above randomness, so &lt;em&gt;maybe&lt;/em&gt; tides have an influence, albeit very small. The additional shear stress caused by tides is 2 to 3 orders of magnitude less than the stress release of an earthquake, so clearly other factors are much more important, such as the extent and location of fluid lubrication, and heterogeneity of friction along the slip plane.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-09-14T05:10:36.277" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8740" PostTypeId="1" AcceptedAnswerId="8741" CreationDate="2016-09-14T17:55:30.803" Score="2" ViewCount="338" Body="&lt;p&gt;I would like to go into mineral excavation as a hobby. What deters me is the fact there are quite a few deadly minerals/ores out there. My question is how likely is it there are those deadly ores in landlocked countries on Balkan peninsula? I know there are some cinnabar findings near me but other deadly minerals are usually found near volcanic vents and other geological formations not characteristic to Balkan peninsula. In statistical terms, how likely is it I will come across those nasty things here?&lt;/p&gt;&#xA;" OwnerUserId="6600" LastActivityDate="2016-09-14T19:36:06.807" Title="Deadly minerals" Tags="|minerals|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8741" PostTypeId="2" ParentId="8740" CreationDate="2016-09-14T19:26:14.353" Score="5" Body="&lt;p&gt;I assume by &quot;mineral excavation&quot; you mean mineral collecting. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've collected minerals for years. In general the biggest danger is naivete not the minerals themselves. You need proper safety equipment, proper tools, and proper planning.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you're  breaking rocking with a hammer, then the hammer should be a soft steel. Hardened steel can splinter. Since the rocks will fragment long sleeve shirts, long pants, and most importantly safety glasses should be used. Boots and gloves would probably be appropriate too. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Don't rock collect alone. Tell someone where you're going and when you plan to come back just in case. Don't go into mines, or collect from under ledges. If you're going somewhere remote plan to take extra food and water - just in case. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cinnabar and other mercury minerals need some care. Any liquid mercury which is spilt gets into cracks and crevices and is essentially impossible to remove. This is dangerous because the metallic mercury literally evaporates into the air and contaminates the air. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another set of minerals that would make me somewhat nervous are radioactive minerals. In general even such specimens can be handled safely with a few precautions since the raw samples have low radioactivity. You just are not going to find big crystals of uranium-235 metal while mineral collecting. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you can afford a small upfront expense micromount collecting is a neat way to go. A large collection of minerals will take up a small space. Micromounters swap and give away specimens much more generously than collectors who want cabinet size specimens. Active mines are virtually impossible to get into. However lots of old mines have tailing piles where good micromount specimens can be found. Lastly I'll also point out that there are several thousand minerals. Only a couple of hundred have good cabinet size specimens.  &lt;/p&gt;&#xA;" OwnerUserId="4685" LastEditorUserId="4685" LastEditDate="2016-09-14T19:36:06.807" LastActivityDate="2016-09-14T19:36:06.807" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8743" PostTypeId="2" ParentId="5386" CreationDate="2016-09-15T01:48:03.993" Score="1" Body="&lt;p&gt;Try something like this:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;[x_grid,y_grid] = meshgrid(1:100,1:100);&#xA;z_grid=griddata(x_data,y_data,z_data,x_grid(:),y_grid(:),'v4');&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;You can change the method of interpolation if you prefer something else.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See:&#xA;&lt;a href=&quot;http://www.mathworks.com/help/matlab/ref/griddata.html&quot; rel=&quot;nofollow&quot;&gt;http://www.mathworks.com/help/matlab/ref/griddata.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4636" LastActivityDate="2016-09-15T01:48:03.993" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8744" PostTypeId="5" CreationDate="2016-09-15T04:03:15.497" Score="0" Body="&lt;p&gt;&lt;a href=&quot;http://www.mathworks.com/products/matlab/&quot; rel=&quot;nofollow noreferrer&quot;&gt;MATLAB&lt;/a&gt; (matrix laboratory) is a multi-paradigm numerical computing environment and proprietary programming language developed by MathWorks. MATLAB allows matrix manipulations, plotting of functions and data, implementation of algorithms, creation of user interfaces, and interfacing with programs written in other languages.&lt;/p&gt;&#xA;" OwnerUserId="-1" LastEditorUserId="11908" LastEditDate="2019-02-03T20:38:56.593" LastActivityDate="2019-02-03T20:38:56.593" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="8745" PostTypeId="4" CreationDate="2016-09-15T04:03:15.497" Score="0" Body="Questions regarding the MATLAB programming language." OwnerUserId="4636" LastEditorUserId="11908" LastEditDate="2019-02-03T20:37:36.977" LastActivityDate="2019-02-03T20:37:36.977" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="8746" PostTypeId="1" AcceptedAnswerId="8783" CreationDate="2016-09-15T12:30:34.010" Score="31" ViewCount="9629" Body="&lt;p&gt;Apologies for the length of the image, which I found at &lt;a href=&quot;http://xkcd.com/1732/&quot; rel=&quot;noreferrer&quot;&gt;http://xkcd.com/1732/&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I'm mostly interested in the temperature line itself, both the historical data and the forward projections.&lt;/p&gt;&#xA;&lt;p&gt;The reason I ask is that I'd like to (in a classroom context) hold this image up as a good example of the visualisation of data, that could be emulated in the area of science relevant to that classroom (zoology). However, I'd first like to check that the data itself is correct.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nVEzu.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nVEzul.jpg&quot; alt=&quot;xkcd 1732&quot; /&gt;&lt;/a&gt;&#xA;(click to enlarge)&lt;/p&gt;&#xA;" OwnerUserId="3341" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-04-10T16:43:17.940" Title="Is this XKCD comic an accurate timeline of the earth's average temperature?" Tags="|climate-change|temperature|" AnswerCount="2" CommentCount="16" ContentLicense="CC BY-SA 3.0" />
  <row Id="8747" PostTypeId="1" AcceptedAnswerId="8750" CreationDate="2016-09-15T14:43:15.660" Score="2" ViewCount="525" Body="&lt;p&gt;It's been said that 55 million years ago, a massive carbon surge raised global temperatures by five to eight degrees (or, in a more preferable translation, nine to 14.4 degrees Fahrenheit).  This catastrophe was known by scientists as &quot;The Paleocene-Eocene Thermal Maximum&quot;, or PETM.  It showed how warm the Eocene was before the opening of the Drake Passage which left Antarctica to be iced, yet it never mentioned what the weather or climate was like &lt;strong&gt;&lt;em&gt;BEFORE&lt;/em&gt;&lt;/strong&gt; the PETM.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the simple question is:  How warm was the Paleocene epoch?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastEditorUserId="111" LastEditDate="2016-09-15T16:41:24.900" LastActivityDate="2016-09-16T14:34:00.837" Title="How Warm Was the Paleocene?" Tags="|temperature|paleoclimatology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8748" PostTypeId="2" ParentId="5248" CreationDate="2016-09-15T17:06:13.447" Score="5" Body="&lt;p&gt;Your approach of adding all the forces together is correct. You have a mistake in in the solution of the $F_{oc}$ integral, though.&#xA;You forgot to integrate the terms $\rho_{w}gh_{w}$ and $-\rho_{oc}gh_{w}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It should read:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$F_{oc} = ... = \rho_{w}gh_{w}(h_{w}+h_{oc}) - \rho_{w}gh_{w}h_{w} + 0.5\rho_{oc}g(h_{w}+h_{oc})^{2} - 0.5\rho_{oc}gh_{w}^{2} - \rho_{oc}gh_{w}(h_{w}+h_{oc}) + \rho_{oc}gh_{w}h_{w} $&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You have to keep this in mind for $F_{M}$ as well.&lt;/p&gt;&#xA;" OwnerUserId="5748" LastEditorUserId="5748" LastEditDate="2016-09-15T17:11:38.197" LastActivityDate="2016-09-15T17:11:38.197" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8750" PostTypeId="2" ParentId="8747" CreationDate="2016-09-16T07:34:35.697" Score="7" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nzFoO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nzFoO.png&quot; alt=&quot;Redrawn after Zachos et al. 2001&quot;&gt;&lt;/a&gt;&#xA;&lt;sub&gt;Redrawn after &lt;a href=&quot;http://science.sciencemag.org/content/292/5517/686&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zachos et al. 2001&lt;/a&gt;.&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a plot of the Cenozoic variations of $\delta\ce{^{18}O}_{Cibicidoides}$ according to Zachos et al. 2001 (this is a bit outdated now but the Paleocene is roughly the same in more modern curves such as &lt;a href=&quot;http://www.nature.com/nature/journal/v451/n7176/full/nature06588.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zachos et al. 2008&lt;/a&gt; or &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2011JC007255/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cramer et al. 2011&lt;/a&gt;). It is supposed to follow variations in deep ocean temperatures and thus reflect the climate state at a given time. The Paleocene is the timeframe delimited by the two vertical bars (you can see the PETM quite clearly on one of the two bars).&lt;br&gt;&#xA;From that plot it seems the Paleocene deep-sea temperature prior to the PETM is roughly at the same level at it is during the Middle Eocene (ca. 45 Ma), i. e. warmer than most of the Cenozoic but colder than the Early Eocene or most of the Cretaceous.&lt;br&gt;&#xA;There isn't actually that many studies focussing on the Paleocene itself, this is clearly a time interval that is studied so far mostly because of the K/T boundary or the PETM, i. e either because of its start or its end.&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2016-09-16T14:34:00.837" LastActivityDate="2016-09-16T14:34:00.837" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8753" PostTypeId="1" CreationDate="2016-09-17T17:42:41.770" Score="1" ViewCount="507" Body="&lt;p&gt;When I saw huge cumulonimbus clouds in the sky I thought the weather would be just fine, but in the evening it started raining. So I just wanted to know what do these clouds really signify.&lt;/p&gt;&#xA;" OwnerUserId="6611" LastEditorUserId="111" LastEditDate="2016-09-18T00:49:23.767" LastActivityDate="2016-09-20T08:54:48.563" Title="What do cumulonimbus clouds signify?" Tags="|atmosphere|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8756" PostTypeId="1" CreationDate="2016-09-18T10:43:40.937" Score="0" ViewCount="215" Body="&lt;p&gt;The pressure at the top of the core is about 1 million bar. That should be enough to create metallic oxygen. So why is the core thought to be iron rather than just metallic oxygen?&lt;/p&gt;&#xA;" OwnerUserId="6615" LastActivityDate="2016-09-18T14:14:45.977" Title="Why is the core of the earth thought to be iron rather than metallic oxygen?" Tags="|core|" AnswerCount="1" CommentCount="1" ClosedDate="2016-09-18T19:20:26.423" ContentLicense="CC BY-SA 3.0" />
  <row Id="8757" PostTypeId="2" ParentId="8756" CreationDate="2016-09-18T14:14:45.977" Score="4" Body="&lt;p&gt;1) The density of the core approximately matches that of high pressure Ni-Fe, but is way denser than solid oxygen (roughly 1.4).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) If the core was oxygen then the overall elemental abundance of the Earth would be nothing like the elemental abundance of anything else in the Solar System (or anywhere else in the known universe).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) The elemental abundance in meteorites, thought to be left-overs of the original accretionary disk, closely matches Earth with an Fe core - doesn't resemble in any way any supposed metallic oxygen core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;4) The seismic data works well if we assume a liquid / solid iron core. If the core was solid oxygen, then the P-wave shadow would be configured completely differently, because seismic refraction at the core-mantle boundary would bend to make shallower refracted waves, not deeper. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;5) A metallic oxygen core would could not explain the Earth's magnetism.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;6) It would be bizarre for an oxygen core to have evolved when there are much heavier elements in the mantle.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-09-18T14:14:45.977" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8758" PostTypeId="1" CreationDate="2016-09-18T14:19:14.830" Score="10" ViewCount="4356" Body="&lt;p&gt;I was looking into tectonic plate boundaries and earthquakes with pictures like these &lt;img src=&quot;https://i.stack.imgur.com/IAXyK.gif&quot; alt=&quot;these&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing that is quite obvious is that some of the plate boundaries have very thin zones of earthquakes, whereas the zones near India, Chile, Australia,.. are much more spread out. What is the cause of this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kim&lt;/p&gt;&#xA;" OwnerUserId="6617" LastEditorUserId="2958" LastEditDate="2019-01-02T08:48:38.057" LastActivityDate="2019-01-02T08:48:38.057" Title="Earthquakes at plate boundaries" Tags="|geology|geophysics|earthquakes|plate-tectonics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="8759" PostTypeId="2" ParentId="8758" CreationDate="2016-09-18T14:49:26.243" Score="8" Body="&lt;p&gt;The cause is partly geometry and partly process. Subduction zones generally take oceanic crust and upper mantle down into the deeper mantle, but the angle of the subduction zone varies greatly. For example, the Tonga Trench is very steep, giving rise to a 'tight' earthquake zone. At its shallowest, the two plate boundary isn't even a subduction zone at all, but becomes obduction, overthrusting oceanic crust/mantle over the plate, as happened with the Oman ophiolite. Then there are ocean-continent collisions, such as western South Americas. Because the continental crust is much less dense than oceanic crust, it is more buoyant, so you get a broader subduction zone than you would with a back arc overlying ocean-ocean collision. Finally, there are continent-continent collisions, typified by India-Tibet, where none of the crust can sink very deep, so you get a stack of imbricate over-thrusts, as in most of Tibet and the Himalayas, all linked to earthquakes over hundreds of kilometres width, as in the Nepalese quake of last year.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also consider the tectonics involved. Where two tectonic plates slide against each other there may be little or no subduction, but stress release in the transcurrent fault can still create major earthquakes - think the San Andreas Fault, or New Zealand. Kim points out the thickness of earthquake zones such as those north of Australia. It isn't just in southeast Asia. We can see similar complexities in the Eastern Mediterranean, the Caribbean and elsewhere, where there are many micro-plates jostling in a complex pattern. They only seem like one seismic zone because of the scale of your diagram. There is yet a different story in the Rift Valley of Africa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The above are just some sketchy simplifications of a revolution in geological understanding that started in the late 1960s, and which are still continuing. It's not possible to give a detailed explanation in this forum, but there are many excellent and fascinating textbooks. Warning - you can get hooked. Then it becomes a lifetime study.  &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-09-18T14:49:26.243" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8764" PostTypeId="2" ParentId="8753" CreationDate="2016-09-20T00:19:14.900" Score="1" Body="&lt;p&gt;Cumulonimbus clouds are thunder clouds, they are heavy and dense clouds that come in large heaps, these clouds produce precipitation or rain, Cumulonimbus clouds also produce hail and tornadoes.&lt;/p&gt;&#xA;" OwnerUserId="5395" LastActivityDate="2016-09-20T00:19:14.900" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8765" PostTypeId="1" CreationDate="2016-09-20T02:28:58.193" Score="1" ViewCount="967" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;I wanted to create my own unique worlds. I wanted to take my readers to places they wouldn’t go to in any other story and show them things they wouldn’t see anywhere else. For instance, the Dry Sea in The View from the Mirror quartet&lt;sup&gt;*&lt;/sup&gt; – a stifling, salt-coated wilderness four kilometers below sea level, is an environment that hasn’t existed on Earth for five million years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I've asked this question in worldbuilding, didn't get a response. They told me to come here. Can someone here explain to me what a Dry Sea is? I've tried to do my own research, but I couldn't find anything on the Dry Sea Ian Irvine stated in the Interview, I copied and pasted from.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;* &lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/0446609862&quot; rel=&quot;nofollow&quot;&gt;That is a book&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="6626" LastEditorDisplayName="user12525" LastEditDate="2019-09-04T11:47:32.303" LastActivityDate="2019-09-04T11:47:32.303" Title="What is a Dry Sea" Tags="|oceanography|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8766" PostTypeId="2" ParentId="8765" CreationDate="2016-09-20T06:20:10.437" Score="3" Body="&lt;p&gt;A dry sea is a location where there was once a sea, but no longer exists or one where the sea only occasionally fills with water before it rapidly dries out. As the water evaporates, salt that was once dissolved in the water precipitates and deposits on what was the sea bed, now the land surface. Dry seas are larger versions of dry lakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sometimes dry seas form naturally and on other occasions, as with the &lt;a href=&quot;https://en.wikipedia.org/wiki/Aral_Sea&quot; rel=&quot;nofollow&quot;&gt;Aral Sea&lt;/a&gt;, their formation is due to human interference with nature.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-09-20T06:20:10.437" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8767" PostTypeId="2" ParentId="8753" CreationDate="2016-09-20T08:45:51.213" Score="0" Body="&lt;p&gt;Cumulonimbus clouds are very high clouds with large amounts of water vapor rising 5-10 kilometers in altitude and they often flatten whey they reach higher than 10km kilometers. Their upper limit is 12.2 kilometers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They from when cold air front arrives in a hot area and sends the hot air with moisture very high up and very forcefully, where it cools and becomes huge clouds. &lt;a href=&quot;https://i.stack.imgur.com/Nd88D.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Nd88D.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2016-09-20T08:54:48.563" LastActivityDate="2016-09-20T08:54:48.563" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8768" PostTypeId="1" CreationDate="2016-09-20T08:52:07.767" Score="2" ViewCount="239" Body="&lt;p&gt;I have a &lt;a href=&quot;http://www.psmsl.org&quot; rel=&quot;nofollow&quot;&gt;PSMSL&lt;/a&gt; &lt;a href=&quot;http://www.psmsl.org/data/obtaining/rlr.php&quot; rel=&quot;nofollow&quot;&gt;RLR (revised local reference)&lt;/a&gt; sea level dataset with records from various tide gauges. Can anyone explain how to correct them for GIA (glacial isostatic adjustment) using the ICE-5G model from &lt;a href=&quot;http://www.psmsl.org/train_and_info/geo_signals/gia/peltier/?&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have a netCDF version with 4 components and some ASCII files. &lt;/p&gt;&#xA;" OwnerUserId="6573" LastEditorUserId="111" LastEditDate="2016-09-20T13:09:19.487" LastActivityDate="2019-05-06T13:58:57.917" Title="How to correct PSMSL data for GIA?" Tags="|geophysics|oceanography|sea-level|tides|netcdf|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8769" PostTypeId="2" ParentId="8765" CreationDate="2016-09-20T11:49:22.080" Score="4" Body="&lt;p&gt;Your reference to 5 million years makes me think you are referring to the desiccation of the Mediterranean Sea. The entire basin almost totally dried out in what is known as the Messinian salinity crisis, about 6.0 to 5.3 million years ago. JOIDES deep sea drilling has proved the desiccation by drilling into salt deposits and subaerial sediments, immediately overlain by deep sea sediments in what are now some of the deepest basins of the Mediterranean. It all came to an end when erosion broke through the Rif-Betic Arc, which was a land bridge between Africa and Europe. When the Atlantic broke through it produced what was probably the most spectacular waterfall in world history - and we missed it by only 5.3 million years, dammit!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your reference mentions '4 kilometres below sea level'. The average depth of the Mediterranean is only 1.5 km, whereas the deepest part is 5.27 km. It is probable that the Nile kept the very deepest part wet even when the rest of the Mediterranean was dry, but desiccation during the late Neogene, to 4 kilometres below current sea level could very well be close to the reality. I can't think of anywhere else in the world where such deep desiccation could have occured. The Dead Sea doesn't even come close. So the reference is probably to &lt;em&gt;the&lt;/em&gt; dry sea, rather than &lt;em&gt;a&lt;/em&gt; dry sea. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Later additional point, I have just recalled that Bischofite, hydrated magnesium chloride, was recovered from the Eastern Mediterranean deep basin at a depth of -3580 metres. This is further proof of near total desiccation, with Mg being concentrated, by solar evaporation, to a brine at nearly 200 x the normal sea-water concentration. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2016-09-22T05:35:10.000" LastActivityDate="2016-09-22T05:35:10.000" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8770" PostTypeId="2" ParentId="8768" CreationDate="2016-09-20T13:23:30.353" Score="2" Body="&lt;p&gt;The simple answer is that you just subtract the nearest value from the glacial isostatic adjustment (GIA) model. The values provided by &lt;a href=&quot;http://www.atmosp.physics.utoronto.ca/~peltier/data.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Peltier&lt;/a&gt; in your netCDF file are in a grid that is 1 degree x 1 degree. So with the lat/lon position from the tidal gauge sea level data, you choose the closest value to your station and apply the correction. In the &lt;a href=&quot;http://www.psmsl.org/train_and_info/geo_signals/gia/peltier/?&quot; rel=&quot;nofollow noreferrer&quot;&gt;PSMSL GIA correction page&lt;/a&gt; they already explain that you should be using the centered value (±250 years). If you decide to use the ASCII files, those are already interpolated to the tide gauge station locations. You have additional information in the U. of Colorado GIA websites(&lt;a href=&quot;http://sealevel.colorado.edu/content/what-glacial-isostatic-adjustment-gia-and-why-do-you-correct-it&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;http://sealevel.colorado.edu/content/gia-faq-updated-peltier-reference&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;) and in the &lt;a href=&quot;http://dx.doi.org/10.1016/S0074-6142(01)80007-3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Peltier (2001) reference&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2019-05-06T13:58:57.917" LastActivityDate="2019-05-06T13:58:57.917" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="8771" PostTypeId="1" CreationDate="2016-09-20T13:28:35.317" Score="0" ViewCount="903" Body="&lt;p&gt;Where in the world can I find a place with mild / warm and non-humid climate all year round?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I'm looking for is a city with these characteristics:&#xA;- monthly average low temperature &gt; 5°C (41°F)&#xA;- monthly average high temperature &amp;lt; 27°C (81°F)&#xA;- low humidity levels&#xA;- at least 500k people&#xA;- English or Spanish as first language&lt;/p&gt;&#xA;" OwnerUserId="6628" LastEditorUserId="6628" LastEditDate="2016-09-20T17:03:51.200" LastActivityDate="2016-09-21T05:21:29.817" Title="Mild climate, low-humidity city all year round" Tags="|meteorology|climate|humidity|" AnswerCount="1" CommentCount="8" ClosedDate="2016-09-30T09:52:29.223" ContentLicense="CC BY-SA 3.0" />
  <row Id="8772" PostTypeId="2" ParentId="8771" CreationDate="2016-09-21T05:21:29.817" Score="3" Body="&lt;p&gt;Low humidity means nowhere near the coast or near any large lakes. Warm winter temperatures without being too hot in summer means tropical high elevation or lower latitude inland sub-tropical. Parts of sub-Saharan Africa might suit, although cities like Kampala or Nairobi have relative humidities which reach the high 70s. As Milancuric writes, you need to be more specific about 'low humidity'. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-09-21T05:21:29.817" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8773" PostTypeId="2" ParentId="7283" CreationDate="2016-09-21T14:39:19.707" Score="1" Body="&lt;p&gt;High up on a peak in Hawaii surrounded by nothing but water in every direction, seeing the curvature can be really quite humbling. As far as the boat theory goes, its not something I'd be able to use considering Im aware of the unnerving sizes of deep sea swells and counting rogue waves, naturally between those the boat is at a low point. Having parents that use to go deep sea fishing often, spending over a week out at sea, the swells are...huge.&lt;/p&gt;&#xA;" OwnerUserId="6632" LastActivityDate="2016-09-21T14:39:19.707" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8776" PostTypeId="1" CreationDate="2016-09-22T08:40:56.570" Score="6" ViewCount="105" Body="&lt;p&gt;I use WRF (Weather research and forecasting) model for in regional scale meteorology simulation. And then, the WRF output files will be deemed as criterial input data applying for chemical transport model(e.g CMAQ, CAMx).       &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The meteorology information are very important for chemical species in the atmosphere. It will influence its emission, diffusion, transportation and removal process and thereby determine the distribution of chemical in horizontal and vertical scales(healthy effect and climate effect related). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the importance of meteorology mode output data, the model evaluation process is essential before applying WRF output file for further use.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Several papers I have read mainly has the similar method that introducing some land-based station data(e.g &lt;a href=&quot;http://www.ncdc.noaa.gov&quot; rel=&quot;nofollow&quot;&gt;NCDC&lt;/a&gt;) within the simulation area and compare them using statistic method. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Usually, we use point-to-point statistic metrics to estimate the similarity of observed data and simulation data in nearest grid in value(&lt;em&gt;MB, RMSE, NMB, NME&lt;/em&gt;) and temporal variation(&lt;em&gt;R&lt;/em&gt;). &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;But I have some &lt;strong&gt;doubt&lt;/strong&gt; here&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;(1) The land-based data is the physics parameters collected from one specific spot and the corresponding WRF output grid data is the average value of the whole area(e.g 9 km^2). They represent the meteorology condition in different scale. What's more, if the station spot is near or at the boundary of grid system, how do we choose the best grid indices?   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) We always regard the land-based observation data as 'true' value. But the instruments also have its own errors. If the observed data has large bias with 'true' physics process, it should be considered as useless. How do we evaluate the observed data itself and analysis it with certain uncertainty?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(3) More detailly, the WRF output data 2-m temperature(RH) and 10-m wind direction/wind are directly used for point-to-point difference. Does it reasonable to compare in these altitude or the value has little difference in several meters range.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think this problem not just exist in WRF model. The air quality model evaluation may has the same issue when comparing simulated value with observed concentration. Is there any more advanced method?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any one has some thought about this question can share your valuable opinion here!&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="5214" LastEditDate="2016-09-22T14:05:50.467" LastActivityDate="2016-09-22T14:05:50.467" Title="Dig in the rationality of model evaluation of WRF with land-based station data" Tags="|atmosphere|atmosphere-modelling|air-pollution|atmospheric-chemistry|wrf|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8778" PostTypeId="1" CreationDate="2016-09-23T00:06:28.220" Score="7" ViewCount="157" Body="&lt;p&gt;Are extratropical cyclones the same as baroclinic waves?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm aware of the fact that extratropical cyclones form in 'baroclinic zones' and that they start of as waves. But are these what are referred to in papers as baroclinic waves e.g. Czaja et al. 2011; Bony et al. 2015. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further to this, are these baroclinic waves the same as the Rossby baroclinic waves?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="6640" LastActivityDate="2022-12-27T20:58:45.197" Title="Are extratropical cyclones the same as baroclinic waves?" Tags="|meteorology|waves|storms|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8779" PostTypeId="1" AcceptedAnswerId="8781" CreationDate="2016-09-23T22:58:35.340" Score="4" ViewCount="2292" Body="&lt;p&gt;I am using NCEP Reanalysis Geopotential height data and this is at 1000 mb and downloading it from here - &lt;a href=&quot;http://www.esrl.noaa.gov/psd/cgi-bin/DataAccess.pl?DB_dataset=NCEP%20Reanalysis%20Pressure%20Level&amp;amp;DB_variable=Geopotential%20height&amp;amp;DB_statistic=Individual%20Obs&amp;amp;DB_tid=54949&amp;amp;DB_did=2&amp;amp;DB_vid=14&quot; rel=&quot;noreferrer&quot;&gt;1000 Mb Geopotential height values&lt;/a&gt; and some of these values are negative for a particular date - May 12th 2014 00Z. I am aware of geopotential height anomalies - &lt;a href=&quot;https://climate.ncsu.edu/images/climate/enso/geo_heights.php&quot; rel=&quot;noreferrer&quot;&gt;Geopotential height anomalies &lt;/a&gt; and that these can be negative i.e. the average of a height surface is lower than than what it should be. But the negative values I am referring to are &quot;raw&quot; geopotential height values and not anomalies. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I sent them a note and asked them what that meant this is the explanation I got - &quot;1000mb geopotential height could be negative if the contour line drawn around the surface of the earth connecting all 1000mb pressure intersected with the earth's surface. At the point where the height was negative, the 1000mb height is actually below the ground and pressure is low.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can someone explain what that means as doing a google on  negative geopotential does not reveal anything meaningful ? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VeAiS.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VeAiS.png&quot; alt=&quot;Geopotential height at 1000 mb for May 12th 2014 00Z&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2016-09-23T23:08:44.077" LastActivityDate="2016-09-26T01:34:47.867" Title="How does one interpret negative geopotential height values?" Tags="|meteorology|atmosphere|measurements|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8780" PostTypeId="1" CreationDate="2016-09-25T05:28:17.730" Score="3" ViewCount="60" Body="&lt;p&gt;I have been reading &lt;a href=&quot;http://pm22100.net/docs/pdf/enercoop/energie/gaz/130316_Methane_Hydrates_and_Contemporary_Climate_Change.pdf&quot; rel=&quot;nofollow&quot;&gt;this paper&lt;/a&gt; and found simple numerical formulations to model the time duration, affected depth and amount of warming of marine sediments. The author uses a rudimentary estimate of the depth to which sediments are affected by an instantaneous, sustained temperature change DT in the overlying air or ocean waters that can be made using the diffusive length scale:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;1 = √kt    (1)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;which describes the depth (m) that 0.5 DT will propagate in elapsed time t (s). k denotes thermal diffusivity, which ranges from ~0.6&#xA;to 1x10-6 m2/s for unconsolidated sediments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For instance, it is said that over 10, 100, and 1000 yr, the calculation yields&#xA;maximum of 18 m, 56 m, and 178 m, respectively, regardless of the magnitude of DT. However, in page 6 (section 3), it is said that using a DT=1.25ºC (plus some other assumptions) during 100 yr of sustained warming affects a depth of ~40 m. How about if just DT is changed to 4ºC? deeper than 40 m in the same 100 yr?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand that (1) can be used to estimate both the time of the sustained warming and the affected depth. However, this formula does not provide a way to define the amount of warming or to estimate how much warming was applied if time and depth are known. Is there a formula for the amount of warming that complements (1)?&lt;/p&gt;&#xA;" OwnerUserId="2713" LastEditorUserId="111" LastEditDate="2016-09-25T12:25:47.557" LastActivityDate="2016-09-25T12:25:47.557" Title="Formula for numerical model for sustained warming in marine sediment?" Tags="|ocean|oceanography|temperature|models|numerical-modelling|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8781" PostTypeId="2" ParentId="8779" CreationDate="2016-09-25T22:00:48.303" Score="5" Body="&lt;p&gt;This likely means that the surface MSLP is less than 1000 mb.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are looking at a 1000 mb geopotential height, and the MSLP at a point is 995 mb, then the height of the 1000 mb geopotential surface would be below the ground, i.e. negative height.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Effectively the question was what does a negative difference of distance from a pressure surface mean? The answer is that the surface must lie below the frame of reference. In the example, the frame of reference is the ground and the surface is the 1000 mb surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/e8elV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/e8elV.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorDisplayName="user1066" LastEditDate="2016-09-26T01:34:47.867" LastActivityDate="2016-09-26T01:34:47.867" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8782" PostTypeId="1" CreationDate="2016-09-25T22:34:09.017" Score="1" ViewCount="358" Body="&lt;p&gt;living in Toronto, and interested in Geology, I am looking for some information on where the Precambrian shield rocks found in the Don Valley / Evergreen Brickworks originated. More specifically, can someone shed some light on how they got there, and what they are called?&lt;/p&gt;&#xA;" OwnerUserId="6655" LastEditorUserId="725" LastEditDate="2016-09-25T23:55:41.193" LastActivityDate="2016-09-25T23:55:41.193" Title="Precambrian shield and Don Valley Brickworks" Tags="|geology|precambrian|canada|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8783" PostTypeId="2" ParentId="8746" CreationDate="2016-09-26T09:52:39.240" Score="10" Body="&lt;p&gt;Yes, it's accurate, see e.g. this picture taken from the Wikipedia &lt;a href=&quot;https://en.wikipedia.org/wiki/Geologic_temperature_record&quot; rel=&quot;noreferrer&quot;&gt;Geologic temperature record&lt;/a&gt; page:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qipRd.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qipRd.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could dig up the source if you wanted from the wikipedia article (or the &lt;a href=&quot;https://en.wikipedia.org/wiki/File:All_palaeotemps.png#Summary&quot; rel=&quot;noreferrer&quot;&gt;graph description page&lt;/a&gt;), but any graph will be generally the same. Since there was an ice age, you'd expect global temperature to be low ~20k years ago and so on.&lt;/p&gt;&#xA;" OwnerUserId="6656" LastEditorUserId="595" LastEditDate="2017-01-27T10:57:30.483" LastActivityDate="2017-01-27T10:57:30.483" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8784" PostTypeId="1" CreationDate="2016-09-26T12:35:22.663" Score="7" ViewCount="109" Body="&lt;p&gt;Over the last approximately six month an auto parts plant in town has started releasing quite a bit of what smells like paint fumes. When it first started it was pretty rare to get an overwhelming breeze, but now it seems quite often, especially at the park a few miles away and often downwind. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since this is a fairly recent new smell in the town, how do I know the EPA or state regulatory office are monitoring this? Who should I contact? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;And after the EPA's failure to disclose lead in Detroit's drinking water, what kind of kits, or testing can I do myself? I have no idea what's in paint that makes it dangerous, only that it should always be done in well ventilated areas, ironically what the auto parts plant is doing.&lt;/p&gt;&#xA;" OwnerUserId="4644" LastActivityDate="2016-09-26T12:35:22.663" Title="Possible new air pollution in town, what to do" Tags="|air-pollution|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8785" PostTypeId="1" AcceptedAnswerId="8786" CreationDate="2016-09-26T18:27:20.353" Score="1" ViewCount="364" Body="&lt;p&gt;Is the length of time, say months, for each season the same all over the world or can it vary? &lt;/p&gt;&#xA;" OwnerUserId="5923" LastActivityDate="2016-09-26T22:12:56.030" Title="Are the length of seasons the same globally?" Tags="|earth-rotation|seasons|time|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8786" PostTypeId="2" ParentId="8785" CreationDate="2016-09-26T22:12:56.030" Score="5" Body="&lt;p&gt;As has been noted in a comment, it depends on how you define seasons (see &lt;a href=&quot;https://earthscience.stackexchange.com/a/2603/111&quot;&gt;https://earthscience.stackexchange.com/a/2603/111&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If seasons are defined in astronomical terms, then they have the same length everywhere on the planet. This is simply down to geometry. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the &lt;em&gt;effects&lt;/em&gt; of astronomical seasons vary geographically in a number of ways. The magnitude of seasonal changes, for example changes in day/night lengths, is more pronounced in higher latitudes, so the effect of (for example) winter might be noticeable for a shorter time period in the tropics than the arctic, and hence some people might reasonably consider winter to be shorter there. There are other, less systematic variations that depend on local climate and weather. In weather terms, not everywhere in the world has the same 4-season cycle that temperate zones tend to experience - so when defining seasons in terms of observable effects one often has,  for example, a wet season and a dry season rather than spring /summer /etc. &lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-09-26T22:12:56.030" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8787" PostTypeId="1" AcceptedAnswerId="14408" CreationDate="2016-09-27T14:35:41.603" Score="8" ViewCount="139" Body="&lt;p&gt;Imagine that we've improved the level quality, affordability, and ease of use of photo-voltaic solar, and it's use is widely distributed in the USA.  We've improved the grid for power distribution, we increase wind, hydro, geothermal sources for 24-hour generation and create a storage network to the point where fossil fuel generation is only needed for, say, 20% of our energy needs, and peak/backup needs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Everyone is happy, bliss abounds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would such a system be vulnerable to a natural disaster?  If there was another Krakatoa event, with an equivalent amount of ash thrown into the atmosphere, how much, percentage-wise, of a reduction in solar intensity would we see, and for how long?&lt;/p&gt;&#xA;" OwnerUserId="6665" LastEditorUserId="111" LastEditDate="2016-09-27T18:36:03.190" LastActivityDate="2018-06-14T09:08:05.487" Title="Would a global cooling event disable solar energy usage?" Tags="|atmosphere|climate|volcanic-hazard|solar-terrestrial-physics|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="8789" PostTypeId="1" CreationDate="2016-09-28T14:32:56.097" Score="5" ViewCount="413" Body="&lt;p&gt;I read a few paper related to emission inventory talking about the inverse modeling. It was another method to estimate the emission from ground(called &lt;code&gt;top-down&lt;/code&gt; method). The satellite sensor usually support the product with vertical column density(&lt;code&gt;VCD&lt;/code&gt;) for certrain species.      &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The target here seems to be generate the relationship between emission and VCD. In my opinion, there are some uncertainty hidden here: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1) the gridded VCD of certain species can be formed by different precursors, transported from neighborhood area.      &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) The chemistry system in the model also has some inherent bias which would miss some crucial source or sink process. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(3) When we set source inventory as input for chemistry transport model, the height information and the specific location are two crucial parameters. In the area of inverse modeling, we know nothing about the information of real sources(i.e fire spot, power plant). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How to generate a relative precise relationship between satellite data and source emission in consideration of these doubts? &lt;/p&gt;&#xA;" OwnerUserId="5214" LastActivityDate="2016-12-06T14:30:26.163" Title="What is principle of inverse modeling?" Tags="|remote-sensing|atmospheric-chemistry|satellites|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8790" PostTypeId="1" CreationDate="2016-09-28T15:16:12.877" Score="4" ViewCount="148" Body="&lt;p&gt;How does NASA get a 360 degrees texture map of Earth and separates it into specularity map, bump map etc? And how do they get the texture map of clouds separate? &lt;/p&gt;&#xA;" OwnerUserId="5395" LastEditorUserId="12590" LastEditDate="2018-04-11T08:08:55.683" LastActivityDate="2018-04-11T08:08:55.683" Title="How does NASA get a 360 degrees texture map of Earth?" Tags="|measurements|geography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8791" PostTypeId="1" AcceptedAnswerId="8793" CreationDate="2016-09-28T15:16:36.940" Score="10" ViewCount="3566" Body="&lt;p&gt;How fast does the Earth's inner-core rotate compared to the Earth's daily rotation? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The inner core is always described as a spinning/rotating solid core while the Earth has a single revolution per day. I've always imagined it as a fast spinning top, but realised I don't actually know if it is a faster spin or slower spin when compared to the Earth's rotation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And even if I knew the speed (which I don't), a number doesn't mean anything unless compared to something relatable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So how much faster/slower is the core rotation compared to the 24 hour day rotation? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Eg the inner core rototes 25 or 2.5times per 1 day. Or the inner core rotates 0.5 times per 1 day. &lt;/p&gt;&#xA;" OwnerUserId="6604" LastActivityDate="2023-03-29T14:25:33.617" Title="How fast does the Earth's inner-core spin?" Tags="|geophysics|core|earth-rotation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8793" PostTypeId="2" ParentId="8791" CreationDate="2016-09-28T22:32:45.253" Score="11" Body="&lt;p&gt;Roughly once per day, but a &lt;em&gt;tiny bit&lt;/em&gt; faster. As the website for Columbia University's Lamont-Doherty Earth Observatory &lt;a href=&quot;http://www.columbia.edu/cu/record/archives/vol22/vol22_iss1/Core_Spin.html&quot;&gt;says&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The inner core rotates in the same direction as the Earth and slightly faster, completing its once-a-day rotation about two-thirds of a second faster than the entire Earth. Over the past 100 years that extra speed has gained the core a quarter-turn on the planet as a whole...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Off the top of my head, I would have doubted that the core had a significantly different rotation rate than the mantle and lithosphere, because it would create different mixing layers in the liquid outer core, resulting in tangles in the Earth's magnetic field, similar to what happens in the Sun.  &lt;/p&gt;&#xA;" OwnerUserId="6467" LastActivityDate="2016-09-28T22:32:45.253" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8795" PostTypeId="1" AcceptedAnswerId="8817" CreationDate="2016-09-30T13:36:06.337" Score="16" ViewCount="1489" Body="&lt;p&gt;The recent news reported by the &lt;a href=&quot;http://www.nytimes.com/2016/09/30/world/europe/iceland-northern-lights-aurora.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;New York Times&lt;/a&gt;, the &lt;a href=&quot;http://www.bbc.com/news/blogs-news-from-elsewhere-37506571&quot; rel=&quot;nofollow noreferrer&quot;&gt;BBC&lt;/a&gt; and the &lt;a href=&quot;http://www.npr.org/sections/thetwo-way/2016/09/29/495946913/reykjavik-turns-off-street-lights-to-turn-up-the-northern-lights&quot; rel=&quot;nofollow noreferrer&quot;&gt;NPR&lt;/a&gt; web sites (for example) as well as in the &lt;a href=&quot;http://icelandreview.com/news/2016/09/28/lights-northern-lights-show&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iceland Review&lt;/a&gt; and &lt;a href=&quot;http://en.vedur.is/weather/forecasts/aurora/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iceland Magazine&lt;/a&gt; sites, about the shutting-off of Reykjavik's streetlights in order to better enjoy the &lt;a href=&quot;https://en.wikipedia.org/wiki/Aurora&quot; rel=&quot;nofollow noreferrer&quot;&gt;Aurora&lt;/a&gt; (northern lights), got me thinking.&lt;/p&gt;&#xA;&lt;p&gt;There are many life-long city dwellers who've never really seen a relatively dark sky or more than a handful of stars. Even people who could do so sometimes have never made the trip out of the city far enough for the experience.&lt;/p&gt;&#xA;&lt;p&gt;So I was curious if this &amp;quot;lights-out&amp;quot; technique could ever be tried in a city or somewhere else besides in Iceland.&lt;/p&gt;&#xA;&lt;p&gt;I'd like to estimate how big of a radius of &amp;quot;lights-out&amp;quot; would an observer need for the sky to be noticeably darker. But for that I'd have to know what is actually doing the scattering, and how far up does it extend.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;My question:&lt;/strong&gt; Why (actually) is the night sky so bright in the city? How far up is that happening?&lt;/p&gt;&#xA;&lt;p&gt;I'm also curious if it is generally stronger in some climates vs others.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2021-04-23T02:59:55.303" LastActivityDate="2021-04-23T02:59:55.303" Title="Why (actually) is the night sky so bright in the city? How far up is that happening?" Tags="|meteorology|atmosphere|humidity|water-vapour|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="8796" PostTypeId="1" AcceptedAnswerId="13713" CreationDate="2016-09-30T14:19:57.920" Score="9" ViewCount="948" Body="&lt;p&gt;Reading the article &lt;a href=&quot;http://www.independent.co.uk/news/science/northern-lights-aurora-borealis-explanation-wrong-magnetic-field-earth-a7233936.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Northern Lights: The traditional explanation for the aurora borealis is wrong, physicist says&lt;/a&gt; I was surprised to find out that the simple, standard explanation for the production of aurora that I have always read and cited (and is described well in &lt;a href=&quot;https://earthscience.stackexchange.com/a/7353/6031&quot;&gt;this answer&lt;/a&gt; and it's linked sources) is at best incomplete.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The article cites &lt;a href=&quot;https://www.britishsciencefestival.org/event/beyond-the-aurora/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this talk&lt;/a&gt; and &lt;a href=&quot;https://www.youtube.com/watch?v=JZcSEdz54k0&quot; rel=&quot;nofollow noreferrer&quot;&gt;this video&lt;/a&gt;. Briefly, the size and brightness of at least some Auroral displays are larger than can actually be explained by particles from the sun simply following field lines down to within a few hundred kilometers of the earth and exciting the atmosphere, especially on the night side.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Magnetic line reconnection can serve as an energy source to accelerate electrons to higher energies (and fluxes?) to produce the more powerful displays.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd like to know - is this reconnection phenomenon important with most displays, or only in highly unusual events? Can Aurora observed at midnight be excited by the energy of the particles as-is (from the sun) or is acceleration from reconnection necessary to insert them on lines that reach to the anti-sunward line on the earth?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following NASA videos appear to be related:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=JZcSEdz54k0&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=JZcSEdz54k0&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=Wd2d3pNS7nM&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=Wd2d3pNS7nM&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=0vY4nDPrEKg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=0vY4nDPrEKg&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2018-03-24T12:22:25.697" Title="What? Northern lights are *not* simply caused by energetic charged particles from the sun?" Tags="|auroras|magnetosphere|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8797" PostTypeId="2" ParentId="4356" CreationDate="2016-09-30T16:25:36.753" Score="4" Body="&lt;p&gt;Try:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.tbs-sct.gc.ca/fcsi-rscf/home-accueil-eng.aspx&quot; rel=&quot;nofollow&quot;&gt;Federal Contaminated Sites Inventory&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;as well as&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://catalogue.data.gov.bc.ca/dataset/crown-contaminated-sites-database&quot; rel=&quot;nofollow&quot;&gt;Crown Contaminated Sites Database&lt;/a&gt; (British Columbia)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.gov.mb.ca/iem/mines/oa_rehabilitation.html&quot; rel=&quot;nofollow&quot;&gt;Orphaned/Abandoned Mine Site Rehabilitation&lt;/a&gt; (Manitoba)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.mndm.gov.on.ca/en/mines-and-minerals/applications/ogsearth/abandoned-mines&quot; rel=&quot;nofollow&quot;&gt;Abandoned Mines Information System-AMIS&lt;/a&gt; (Ontario)&lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2016-09-30T16:25:36.753" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8798" PostTypeId="1" CreationDate="2016-09-30T20:40:49.907" Score="10" ViewCount="6464" Body="&lt;p&gt;On Earth we find many kind of minerals, a lot of them are silicates. How much different kind of minerals would there be on Earth?&#xA;But are there Fe minerals found in meteorites which do no occur on Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;And how many combinations of metals/elements are possible to form minerals which doesn't exist on Earth. And what could be the reason that they don't exist on Earth?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="725" LastEditDate="2016-10-01T06:40:34.970" LastActivityDate="2023-06-01T20:09:54.143" Title="Are there minerals which are not been found on earth but which are still possible to exist?" Tags="|geology|geochemistry|mineralogy|crystallography|" AnswerCount="5" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8799" PostTypeId="2" ParentId="8798" CreationDate="2016-09-30T21:15:53.957" Score="10" Body="&lt;p&gt;To answer the first part, there are many minerals on earth which do not involve silicate bonded structures. For instance, non-silicates (minerals of carbonates, sulfides, sulfates, phosphates, and oxides are common non-silicate varieties). For a detailed list of mineral species, you should check out the Dana Classification here: &lt;a href=&quot;http://webmineral.com/danaclass.shtml#.V-7Py_ArKCg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Minerals Arranged by the New Dana Classification&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are indeed Fe minerals which have no occurrence on Earth, outside originating from meteorite impacts. These minerals are various lattice polymorphs of Fe wit Ni. Kamacite and Taenite are examples of minerals which are found exclusively in meteorites, often distinguished by a Widmanstätten pattern.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question as to how many possible mineral-producing elemental combinations are possible outside the bounds of our own planet, is outside my personal knowledge in a numerical sense, but the current known naturally occurring mineral species recognized by the IMA numbers around 5,141 valid species: &lt;a href=&quot;http://nrmima.nrm.se//imalist.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;The official IMA-CNMNC List of Mineral Names&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I may be outside the bounds of certain knowledge here, but restrictions on extraterrestrial mineral formation are likely akin to those on Earth: temperature, pressure, time, fluid composition (be it magma, or some aqueous solution), gravity, and atmospheric composition, just to name a few. Some minerals may be unable to exist on our planet because the formational/stability conditions of Earth do not offer much permanence. These prohibiting conditions could well be absent on certain other planets/stellar bodies.&lt;/p&gt;&#xA;" OwnerUserId="6680" LastEditorUserId="6093" LastEditDate="2016-11-28T16:41:32.423" LastActivityDate="2016-11-28T16:41:32.423" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8800" PostTypeId="2" ParentId="8798" CreationDate="2016-10-01T01:30:07.137" Score="3" Body="&lt;p&gt;To put things in perspective, as Tachylite says, there are about 5150 known natural mineral species on Earth. Despite more mineralogists and better analytical equipment than ever before, the discovery of new minerals has dropped to a mere trickle. In some years there are no new mineral discoveries, although four new minerals were discovered both last year and this year (2015-16). In many cases a review of old museum specimens reveals misdiagnosis of old minerals and discovery of new minerals. It is estimated, by extrapolation of known chemistries and paragenetic conditions, that there are at least 145 new carbon minerals waiting to be discovered on the Earth's surface. It is also known that there are ultra-cold organic minerals on at least Pluto, Titan, Europa, and probably billions of comets and other Kuiper-belt objects. Who knows what organic minerals are out there? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The full catalogue of Earth's surface or near surface minerals will never be known, but may converge on about 6000. This number also depends upon how you define a mineral, and how many minerals you count in a solid-solution series. The total number of minerals is probably vastly more than 6000. Three minerals thought to have been unique to the moon have since been found on Earth - but we have only explored a minute fraction of the moon's surface.  In addition, we can guess, but don't know for sure, what extreme pressure-temperature mineral assemblage occurs in the Earth's lower mantle and solid core - probably many more than our simplistic models tend to assume. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The solar system only gives us one basic starting mix of elements. But, especially towards the core of the galaxy, there will be countless stellar systems which have undergone many more cycles of stellar nucleosynthesis, resulting in a radically different mix of starting elements. These evolving stellar systems will span a range of temperature-pressure conditions which far exceeds that of Earth, so it is reasonable to assume that there will be a huge range of minerals in the galaxy, which we have never even imagined.  &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-10-01T01:30:07.137" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8801" PostTypeId="2" ParentId="8798" CreationDate="2016-10-01T06:51:18.643" Score="4" Body="&lt;p&gt;First of all, there is this question and answer that might be relevant:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/8290/725&quot;&gt;Were all of Earth&amp;#39;s minerals created before Earth&amp;#39;s formation, during, or after?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also notice the bit about &quot;mineral evolution&quot;. If you dig more into Bob Hazen and colleagues work, they have some paper where they estimate how much more minerals are expected to exist that we have yet to find.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tachylite's answer is mostly correct. I'd like to add a few more things though:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;And how many combinations of metals/elements are possible to form minerals which doesn't exist on Earth&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Hundreds of thousands. There are 90 something (relevant) elements in the periodic table, some of them have different oxidation states, which basically makes them behave as different elements. For example S&lt;sup&gt;2-&lt;/sup&gt; and S&lt;sup&gt;6+&lt;/sup&gt; are both sulfur, but they are completely different mineralogically. This leads to almost infinite amount of possible compounds and minerals.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;And what could be the reason that they don't exist on Earth?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The conditions are not correct. Mineral stability is a function of temperature, pressure, bulk composition and fugacity (activity) of certain volatile components such as oxygen, sulfur, etc. Only a limited set of combinations of those is available on Earth, so that's why they might not exist here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, several minerals are known from synthetic experiments to occur in the Earth, and actually a large amount of of the Earth's mantle is predicted to comprise of them. Two examples are ringwoodite and bridgmanite. Both were first synthesised in a lab, and were found in meteorites. Ringwoodite was only recently found as an inclusion in super-deep diamonds, and bridgemanite was not found yet in the Earth. We do know that the mantle is full of that, it's just not accessible to us.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is similar to all of the Fe minerals that are found in meteorites. It's likely that Earth's core is composed of a bunch of Fe minerals we don't even know yet, but they are not accessible to us so we basically can only guess based on experimental studies.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-10-01T06:51:18.643" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8802" PostTypeId="1" CreationDate="2016-10-01T11:58:58.303" Score="3" ViewCount="515" Body="&lt;p&gt;As far as I know tsunamis are caused by landslides at the bottom of the sea. But an asteroid impacting the sea is a different phenomena. Could it still cause a &quot;tsunami&quot; as in an unstoppable mass of water propagating towards the shores? Is there a need of distinction between these two phenomena, or do they add up to the same thing?&lt;/p&gt;&#xA;" OwnerUserId="3033" LastEditorUserId="725" LastEditDate="2016-10-01T23:02:38.113" LastActivityDate="2016-10-01T23:02:38.113" Title="Would an oceanic asteroid impact really cause a tsunami?" Tags="|tsunami|natural-disasters|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8803" PostTypeId="2" ParentId="8802" CreationDate="2016-10-01T13:42:44.753" Score="7" Body="&lt;p&gt;An asteroid impact in the ocean is an oversized example of throwing a pebble in a pond - both will produce waves in a concentric pattern from the point of impact.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The height of the waves and the energy they would have would depend on the amount of energy the asteroid transferred to the water at the impact sight.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The energy transferred will depend on the kinetic energy of the asteroid at the moment of impact, this being a function of the mass and velocity of the asteroid; based on the classical equation for kinetic energy: $E_k = 0.5mv^2$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hence, an asteroid with a very large mass and high velocity could transfer enough energy that could create tsunamis. The best example of this is the impact that created the &lt;a href=&quot;https://en.wikipedia.org/wiki/Chicxulub_crater&quot;&gt;Chicxulub crater&lt;/a&gt; in the Yucatan peninsular, that lead to the creation of the K-T boundary and the extinction of the dinosaurs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That impact created a mega tsunami that affected the coastal southern state of the USA, from Texas to Florida.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-10-01T13:42:44.753" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8804" PostTypeId="2" ParentId="4234" CreationDate="2016-10-02T22:29:33.597" Score="1" Body="&lt;p&gt;Besides the event in 1654 in China, there was a time with snow in Cuba 23N in the 19th century, and in Jan 2016 snow fell near sea level in Taiwan 23N.&lt;/p&gt;&#xA;" OwnerUserId="6686" LastActivityDate="2016-10-02T22:29:33.597" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8805" PostTypeId="1" CreationDate="2016-09-30T15:10:28.873" Score="4" ViewCount="253" Body="&lt;p&gt;I convert data from $t$-$x$ domain to $f$-$k$ domain to do dip filter using &lt;code&gt;sudipfilt&lt;/code&gt; command. After that it should return to the $t$-$x$ domain. Which command should it be?&lt;/p&gt;&#xA;" OwnerUserId="5551" OwnerDisplayName="Liath Fahad" LastEditorUserId="28050" LastEditDate="2018-04-05T00:23:03.167" LastActivityDate="2018-04-05T00:23:03.167" Title="How to do inverse Fourier transformation with Seismic Unix?" Tags="|software|seismic|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8806" PostTypeId="1" CreationDate="2016-10-03T06:52:20.240" Score="78" ViewCount="61724" Body="&lt;p&gt;I'm curious if there are any saltwater rivers on Earth. These would presumably arise if a saltwater lake had a river outlet to the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, all the saltwater lakes I looked at (Caspian Sea, Dead Sea, Great Salt Lake Utah), apparently don't have any river outlets.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do any exist? And the obvious follow up, why or why not?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt; For the purposes of this question, undersea flows don't count. They are fascinating, but I'm interested if any &quot;regular surface rivers&quot; exist as saltwater rivers.&lt;/p&gt;&#xA;" OwnerUserId="2733" LastEditorUserId="11908" LastEditDate="2019-03-04T00:40:13.770" LastActivityDate="2023-07-26T01:29:26.643" Title="Are there any saltwater rivers on Earth?" Tags="|hydrology|geography|rivers|salinity|estuary|" AnswerCount="21" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="8807" PostTypeId="2" ParentId="8806" CreationDate="2016-10-03T07:50:10.097" Score="86" Body="&lt;p&gt;The water in any river draining the sea is infinitely recycle-able (from rain replenishment), whereas the salt from any terrestrial source is not. So salty rivers, if any, won't exist permanently. Saltwater lakes gain their salinity precisely because they have no outlet, so salt just gets concentrated by evaporation. I don't think there are any truly saline rivers throughout their entire length.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The nearest approximations I can think of are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Rare ephemeral runoff from emergent salt domes in desert areas.&lt;/li&gt;&#xA;&lt;li&gt;Freshwater rivers that drain into arid areas where combined evaporation and infiltration gradually reduces the flow to zero. These are more 'very brackish' than truly saline. The Amu Darya in Uzbekistan is one such example. I don't know the salinity of the Jordan as it enters the Dead Sea, but the river is reduced to almost nothing, whilst there are hypersaline springs, and sewage effluent from Amman draining into it.&lt;/li&gt;&#xA;&lt;li&gt;The only river I can think of that is very highly mineralized from source to sea is only about 3 kilometres long. It is an unnamed river from the volcanic crater on Savo Island, in the Solomon Islands (Southwest Pacific). It is also acidic and boiling hot - quite literally, for most of it's length. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="5197" LastEditDate="2016-10-04T11:21:42.523" LastActivityDate="2016-10-04T11:21:42.523" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8808" PostTypeId="1" AcceptedAnswerId="8810" CreationDate="2016-10-03T08:24:27.987" Score="3" ViewCount="121" Body="&lt;p&gt;There are several mentions in the net about Spanish radar satellite called &quot;PAZ&quot;, which should work in tandem with German TerraSAR-X and should have been launched in 2015. But most results I can find talk about plans, and no real announcement that it has been successfully launched. Anyone knows the current status of it?&lt;/p&gt;&#xA;" OwnerUserId="3385" LastEditorUserId="111" LastEditDate="2016-10-03T13:44:42.360" LastActivityDate="2016-10-03T13:44:42.360" Title="Has PAZ satellite been launched?" Tags="|earth-observation|satellites|radar|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8809" PostTypeId="1" CreationDate="2016-10-03T09:32:58.413" Score="3" ViewCount="60" Body="&lt;p&gt;I do have a large dataset containing nearly a decade of particulate matter measurements. At the lower precision limit of the measuring instrument, there are values given like &lt;code&gt;&amp;lt; 8&lt;/code&gt;. For statistical analysis however, a defined value is needed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the best possible way to deal with this? &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Replacing it as missing values?&lt;/li&gt;&#xA;&lt;li&gt;Replacing it by &lt;code&gt;8&lt;/code&gt; or even &lt;code&gt;7&lt;/code&gt; (&lt;code&gt;&amp;lt; 8&lt;/code&gt;)?&lt;/li&gt;&#xA;&lt;li&gt;Assuming &lt;code&gt;0&lt;/code&gt;?&lt;/li&gt;&#xA;&lt;li&gt;Assuming the mean value between something like &lt;code&gt;0&lt;/code&gt; and &lt;code&gt;8&lt;/code&gt;; e. g. &lt;code&gt;4&lt;/code&gt;?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Or is there a better solution, maybe considering the natural background value?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT:&#xA;I'd like to calculate the intra-day- and intra-year distribution, as well as searching for patterns by considering wind directiond and speed.&lt;/p&gt;&#xA;" OwnerUserId="4784" LastEditorUserId="4784" LastEditDate="2016-10-03T10:39:02.540" LastActivityDate="2016-10-03T10:39:02.540" Title="Determining '&lt; x' values as numeric" Tags="|measurements|air-pollution|statistics|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8810" PostTypeId="2" ParentId="8808" CreationDate="2016-10-03T13:43:50.857" Score="2" Body="&lt;p&gt;The launch was scheduled for 2017 using a DNPER launch vehicle. It seems that the contract contract between Kosmotras and Hisdesat &lt;a href=&quot;http://spaceflights.news/?launch=dnepr-%E2%80%A2-paz&quot; rel=&quot;nofollow noreferrer&quot;&gt;was canceled&lt;/a&gt; and that resulted in an uncertain launch date. The satellite has been finished since 2013 and it has been waiting for over 3 years to be launched.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EqQfT.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EqQfT.jpg&quot; alt=&quot;Paz satellite&quot;&gt;&lt;/a&gt;&lt;a href=&quot;http://ep01.epimg.net/politica/imagenes/2016/07/19/actualidad/1468951759_250653_1468952706_noticia_normal_recorte1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The dispute between Russia and Ukraine resulted in EU imposing sanctions on Moscow. As a result, Russian President Vladimir Putin supposedly signed a secret decree halting launches of the Dnepr rocket (based on the Soviet-era R-36M missile that was made in Ukraine). It also affected the launch of several satellites of the Iridium constellation. With the Russian government withholding approval for the launch, everything felt apart and now the parent company (&lt;a href=&quot;http://www.hisdesat.es/eng/satelites_observ-paz.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;hisdeSAT&lt;/a&gt;) has to find another launch platform. &lt;a href=&quot;http://elpais.com/elpais/2016/07/20/inenglish/1469002393_087157.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;The two main candidates are the Soyuz rocket from Roscosmos and the Falcon rocket from Space-X, but the cost of either alternative is much higher.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2016-10-03T13:43:50.857" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8811" PostTypeId="2" ParentId="8806" CreationDate="2016-10-03T14:49:57.060" Score="35" Body="&lt;p&gt;The already accepted answer is already covering the &amp;quot;real&amp;quot; answer as far as I'm concerned, and while you won't find many (any?) saline rivers in the traditional sense, we do have underwater &amp;quot;rivers&amp;quot; that &lt;em&gt;kiiiiind of but not quite&lt;/em&gt; fit the bill. They're not saline rivers as I expect you envision, but I figure they could be an interesting &amp;quot;by the way though&amp;quot; answer to the question anyway.&lt;/p&gt;&#xA;&lt;p&gt;One good example is The Black Sea undersea river. The actual article in which it is originally posted seems to be unaccessible right now, so adding a more &amp;quot;prosaic&amp;quot; description of it:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;It stems from salty water spilling through the Bosphorus Strait from the Mediterranean into the Black Sea, where the water has a lower salt content. This causes the dense water from the Mediterranean to flow like a river along the seabed, carving a channel and deep banks. 'It flows down the sea shelf and out into the abyssal plain much like a river on land,&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/cHZDh.jpg&quot; alt=&quot;A 3-D radar image, using false color, of the undersea river channel where it enters the Black Sea from the Bosphorus Strait.&quot; title=&quot;A 3-D radar image, using false color, of the undersea river channel where it enters the Black Sea from the Bosphorus Strait.&quot; /&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So much water flows through the Black Sea undersea river that it is estimated to possibly being the sixth largest river in the world.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Another, perhaps more visually impactful example might be the Cenote Angelita in Mexico, and although this isn't a river at all, it &lt;em&gt;looks&lt;/em&gt; very much like one. The Cenote Angelita is a heavily saline mass of water found at the bottom of a fresh water cave, with a layer of Hydrogen Sulfate separating the two watermasses, snaking around in cracks and layers that make it look like a river. As far as I understand it, the waters here are essentially static and unmoving, which has caused the heavier saline water to sink to the bottom, while the fresh water lies on top. Essentially the same as when you put oil in a cup of water.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oQKLc.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oQKLc.jpg&quot; alt=&quot;Cenote Angelita&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6690" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-10-05T08:12:47.320" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8812" PostTypeId="2" ParentId="8806" CreationDate="2016-10-03T15:16:37.313" Score="18" Body="&lt;p&gt;Here in New York City we have a salt &quot;river&quot;.  It is called the &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/East_River&quot; rel=&quot;noreferrer&quot;&gt;East River&lt;/a&gt;&quot; and it separates part of Long Island (Brooklyn and Queens) from the island of Manhattan and the mainland (The Bronx).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Indeed it looks a lot like a salt river:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vETmP.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vETmP.jpg&quot; alt=&quot;East River&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From a hydrology perspective it is not a river tho, it is actually a saltwater estuary.&lt;/p&gt;&#xA;" OwnerUserId="6692" LastEditorUserId="6692" LastEditDate="2016-10-04T18:18:09.127" LastActivityDate="2016-10-04T18:18:09.127" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8813" PostTypeId="2" ParentId="8806" CreationDate="2016-10-03T17:59:59.627" Score="6" Body="&lt;p&gt;There are specific rivers that sometimes flow inward called &lt;a href=&quot;https://en.wikipedia.org/wiki/Tidal_bore&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tidal Bores&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A great example of a Tidal Bore is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Amazon_River&quot; rel=&quot;nofollow noreferrer&quot;&gt;Amazon River&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xPFpP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xPFpP.png&quot; alt=&quot;pororoca&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5180" LastEditorUserId="12057" LastEditDate="2018-02-27T02:28:15.097" LastActivityDate="2018-02-27T02:28:15.097" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8814" PostTypeId="2" ParentId="8714" CreationDate="2016-10-04T04:32:48.450" Score="2" Body="&lt;p&gt;Tohoku is the seismogenic zone, the asperity model explained this small repeating earthquake well. It was said massive earthquake will occur in Nankai Trough. As their expectation was wrong, [Kato and Yoshida, 2011],[Hori and Miyazaki, 2011] created new models.&#xA;ref &lt;a href=&quot;http://www1.kaiho.mlit.go.jp/GIJUTSUKOKUSAI/KENKYU/happyo/2011/h23sp.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Notice japanese source&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is new model of Sansoken(National institute of advanced industrial science and technology). In this model, asperity model is still alive.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/6yaNR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6yaNR.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5180" LastActivityDate="2016-10-04T04:32:48.450" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8815" PostTypeId="2" ParentId="8806" CreationDate="2016-10-04T09:32:13.143" Score="6" Body="&lt;p&gt;Here in Norway we are mighty proud of &quot;Saltstraumen&quot;(meaning Salt Stream)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Again, not technically a river, but a narrow strait connecting the ocean to a wider fjord behind it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the tides go in and out, Saltstraumen does too.  It is the world's strongest tidal current.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Saltstraumen&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia link.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6697" LastActivityDate="2016-10-04T09:32:13.143" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8816" PostTypeId="2" ParentId="8806" CreationDate="2016-10-04T12:34:52.763" Score="25" Body="&lt;p&gt;Water from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Caspian_Sea&quot;&gt;Caspian sea&lt;/a&gt;, with a salinity of 1.2%, is constantly flowing into &lt;a href=&quot;https://en.wikipedia.org/wiki/Garabogazk%C3%B6l&quot;&gt;Garabogazköl&lt;/a&gt;, where the water eventually evaporates and leaves the salt behind. Of course, the situation is not indefinitely stable, as the depression is eventually going to be filled with salt. But at the time writing, water is still flowing like a river through the very narrow inlet:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kGjJB.png&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kGjJB.png&quot; alt=&quot;Garabogazköl&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5333" LastActivityDate="2016-10-04T12:34:52.763" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8817" PostTypeId="2" ParentId="8795" CreationDate="2016-10-04T12:47:29.917" Score="15" Body="&lt;p&gt;What's actually happening is scattering of light, both off of aerosol particles and nitrogen and oxygen molecules.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a review of quantitative models of light pollution as a function of distance from cities see &lt;a href=&quot;http://articles.adsabs.harvard.edu//full/1991ASPC...17...56G/0000056.000.html&quot; rel=&quot;noreferrer&quot;&gt;Light Pollution Modeling&lt;/a&gt; . Some consider height as well as distance.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get a rough estimate of what size of lights-out event would be needed to obtain a particular improvement in sky darkness, I would suggest looking at the light pollution map at &lt;a href=&quot;http://darksitefinder.com/maps/world.html&quot; rel=&quot;noreferrer&quot;&gt;Dark Site Finder&lt;/a&gt; or &lt;a href=&quot;http://www.lightpollution.it/worldatlas/pages/fig1.htm&quot; rel=&quot;noreferrer&quot;&gt;The night sky in the World&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Colours correspond to ratios between the artificial sky brightness and the natural sky brightness of: &amp;lt;0.01 (black), 0.01-0.11 (dark-gray), 0.11-0.33 (blue), 0.33-1 (green), 1-3 (yellow), 3-9 (orange), 9-27 (red), &gt;27 (white)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Look at a coastal city such as Miami (which is extremely light-polluted) and see how the degree of light pollution drops off with distance from the city. Or look at a very isolated city such as Bismark, North Dakota.  I would estimate 20 to 40 kilometers away from a source you see a factor of 10 reduction in artificial brightness.  &lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2018-07-30T10:32:17.147" LastActivityDate="2018-07-30T10:32:17.147" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="8818" PostTypeId="1" AcceptedAnswerId="8821" CreationDate="2016-10-04T13:33:36.817" Score="5" ViewCount="96" Body="&lt;p&gt;I have a set of very old precipitation anomaly maps, from 1995-2006 for Brazil. The data of these maps, is to the best of my knowlegde, lost.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to have them digitalized, ie, to NetCDF or another similar gridded format. Is there any tools recommendend for this job?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The figure below is a recent plot, similar to my files.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bRF40.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bRF40.gif&quot; alt=&quot;similar plot&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6700" LastEditorUserId="111" LastEditDate="2016-10-04T13:45:15.777" LastActivityDate="2016-10-04T23:09:11.627" Title="Digitalizing precipitation data from the image of weather map" Tags="|meteorology|precipitation|software|netcdf|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8819" PostTypeId="1" AcceptedAnswerId="8942" CreationDate="2016-10-04T17:54:41.737" Score="7" ViewCount="6693" Body="&lt;p&gt;I'm currently doing research for a paper in school where we need to research on a university-like level. When I read the paper &lt;em&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2015GL063306/pdf&quot; rel=&quot;nofollow&quot;&gt;Causes and impacts of the 2014 warm anomaly in the NE Pacific&lt;/a&gt;&lt;/em&gt;, I found the sentence:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The wind stress curl was negative, which has precedence but is still quite unusual.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The wind stress curl was given as $-0.5*10^6 \ \text{N}*m^{-3}$. I neither know what wind stress curl is, nor what the negative sign is, nor what the unit of it exactly describes (of course, pressure per meter, but what does that mean?).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone explain what it is?&lt;/p&gt;&#xA;" OwnerUserId="6702" LastEditorUserId="20" LastEditDate="2016-10-15T00:37:46.263" LastActivityDate="2016-10-23T02:56:59.927" Title="What is (negative) wind stress curl?" Tags="|geophysics|ocean|oceanography|water|wind|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8821" PostTypeId="2" ParentId="8818" CreationDate="2016-10-04T22:04:04.357" Score="4" Body="&lt;p&gt;You can convert the image to NetCDF data using &lt;code&gt;gdal_translate&lt;/code&gt;. The command line looks something like:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;gdal_translate -ot Int16 -of netCDF jpeg_filename nc_filename&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;You can use ncl example: &lt;a href=&quot;https://www.ncl.ucar.edu/Applications/Scripts/topo_9.ncl&quot; rel=&quot;noreferrer&quot;&gt;click here&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4877" LastEditorUserId="20" LastEditDate="2016-10-04T23:09:11.627" LastActivityDate="2016-10-04T23:09:11.627" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8822" PostTypeId="1" CreationDate="2016-10-04T23:51:33.730" Score="4" ViewCount="1308" Body="&lt;p&gt;Not sure if it is the right place to post this question but I'd like to know where to find a wildfire database? I don't need any geospatial data.  Just a list of the wildfires that happened in USA from 1960 to present is needed. Wildfires of interest include both human and lightning caused.&lt;/p&gt;&#xA;" OwnerUserId="5771" LastEditorUserId="543" LastEditDate="2016-10-05T03:46:55.280" LastActivityDate="2016-11-04T03:48:56.450" Title="Where can I find a database of historical wildfires in the USA back to 1960?" Tags="|database|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8823" PostTypeId="2" ParentId="8822" CreationDate="2016-10-05T03:43:56.317" Score="1" Body="&lt;p&gt;I would suggest the &lt;a href=&quot;https://www.nifc.gov/fireInfo/fireInfo_statistics.html&quot; rel=&quot;nofollow&quot;&gt;National Interagency Fire Center&lt;/a&gt;, which keeps statistics in a variety of formats as well as lists of historical fires.  For instance, you can see a list of historically significant fires as far back as 1804 &lt;a href=&quot;https://www.nifc.gov/fireInfo/fireInfo_stats_histSigFires.html&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;.  In general, the closer you get to present, the more information about fires there is.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other websites with historical wildfire lists include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_wildfires#North_America&quot; rel=&quot;nofollow&quot;&gt;Wikipedia&lt;/a&gt; list of large fires&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://wildfire.cr.usgs.gov/firehistory/data.html&quot; rel=&quot;nofollow&quot;&gt;USGS&lt;/a&gt; spatial data back to 1980 with a viewer &lt;a href=&quot;http://wildfire.cr.usgs.gov/firehistory/viewer/viewer.htm&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/paleoclimatology-data/datasets/fire-history&quot; rel=&quot;nofollow&quot;&gt;NOAA&lt;/a&gt; World Data Center&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="543" LastActivityDate="2016-10-05T03:43:56.317" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8824" PostTypeId="2" ParentId="446" CreationDate="2016-10-05T10:44:05.257" Score="1" Body="&lt;p&gt;When the one molecule of Neo's answer change the direction a bit, the chain of all molecules move. This may bring the phenomenon like kaleidscope.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XaYps.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XaYps.jpg&quot; alt=&quot;kale&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5180" LastActivityDate="2016-10-05T10:44:05.257" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8826" PostTypeId="2" ParentId="8806" CreationDate="2016-10-05T18:47:07.293" Score="9" Body="&lt;p&gt;There is an area with several salt rivers and wide salt streams that exists in Russia - it's in &lt;a href=&quot;https://en.wikipedia.org/wiki/Yakutsk&quot; rel=&quot;nofollow&quot;&gt;Yakutia&lt;/a&gt; (&lt;a href=&quot;https://en.wikipedia.org/wiki/Sakha_Republic&quot; rel=&quot;nofollow&quot;&gt;Sakha Republic&lt;/a&gt;), part of &lt;a href=&quot;https://en.wikipedia.org/wiki/Siberia&quot; rel=&quot;nofollow&quot;&gt;Siberia&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Water of &lt;a href=&quot;https://en.wikipedia.org/wiki/Solyanka_River&quot; rel=&quot;nofollow&quot;&gt;Solyanka River&lt;/a&gt; (flowing in to the great &lt;a href=&quot;https://en.wikipedia.org/wiki/Lena_River&quot; rel=&quot;nofollow&quot;&gt;Lena River&lt;/a&gt;) contains 21&amp;nbsp;g of salt per liter, some neighboring streams can contain up to 70&amp;nbsp;g of salt per liter of their water...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to science, millions years ago this territory was covered by a large sea. Later, due to uplift of the crust it was divided into many salt lakes in numerous cavities. And after the water has dried up - large stratum of salt remained inside the earth. So modern rivers and streams flowing through this stratum are fully saturated with salt.&lt;/p&gt;&#xA;" OwnerUserId="6718" LastEditorUserId="502" LastEditDate="2016-10-08T12:35:35.023" LastActivityDate="2016-10-08T12:35:35.023" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8827" PostTypeId="2" ParentId="8806" CreationDate="2016-10-05T18:57:53.943" Score="29" Body="&lt;p&gt;The Pecos River in Texas, USA may arguably fit the description of a &amp;quot;saltwater river&amp;quot;. A point of argument is what is considered to be &amp;quot;saltwater&amp;quot;. For comparison, here are some &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_bodies_of_water_by_salinity&quot; rel=&quot;noreferrer&quot;&gt;bodies of water and their salinity&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;35,000 ppm Pacific and Atlantic Ocean&lt;/li&gt;&#xA;&lt;li&gt;13,000-23,000 ppm Black Sea&lt;/li&gt;&#xA;&lt;li&gt;12,500 ppm Caspian Sea&lt;/li&gt;&#xA;&lt;li&gt;10,000 ppm Baltic Sea&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Note though, that salinity varies based on where, and at what depth you measure it. For example, the Baltic Sea has &lt;a href=&quot;https://en.wikipedia.org/wiki/Baltic_Sea#Salinity&quot; rel=&quot;noreferrer&quot;&gt;salinity as low as 5,000 to 8,000 ppm&lt;/a&gt; at the surface of the central basin.&lt;/p&gt;&#xA;&lt;p&gt;At its saltiest, the Pecos River is reaching the lower end of the range above. Different sources give different threshold between the definitions of freshwater, brackish water, and saline water. Most would probably deem the Pecos as brackish (which would describe the Baltic Sea by the same standard), but it is salty enough to be a problem for human use. There are a number of sources that discuss the issue of the Pecos River and its salinity, but I'll &lt;a href=&quot;http://twri.tamu.edu/media/574249/tr-470.pdf&quot; rel=&quot;noreferrer&quot;&gt;direct you to this one&lt;/a&gt;, and quote a little from it&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Pecos River is among the saltiest rivers in North America with&#xA;salinity levels regularly exceeding 7,000 ppm at the Texas and New&#xA;Mexico border and 12,000 ppm near Girvin, Texas. High salinity in the&#xA;river has adversely affected the stability and biodiversity of the&#xA;riparian ecosystems, as well as, the economic uses of the river and&#xA;reservoirs.&lt;/p&gt;&#xA;&lt;p&gt;In general, natural sources of salt throughout the watershed cause the&#xA;Pecos to be salty.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;If you look at the slides in &lt;a href=&quot;http://docslide.us/documents/salinity-control-on-the-pecos-river.html&quot; rel=&quot;noreferrer&quot;&gt;this presentation&lt;/a&gt; you'll see that different measurement locations range from around 1,000 ppm to 12,000 ppm (it gives measurements in mg/l, but that is roughly equivalent to ppm). It also gives historical measurement graphs for some select stations. The presentation also highlights that there is a history of efforts to engineer a reduction of the river's salinity.&lt;/p&gt;&#xA;&lt;p&gt;The source of the Pecos River's saltiness is not so much surface salt as it is subsurface sources in the form of saline aquifers that feed the river through salt springs, for example. &lt;a href=&quot;http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=1993&amp;amp;context=greatplainsresearch&quot; rel=&quot;noreferrer&quot;&gt;This research paper&lt;/a&gt; suggests that although the Pecos was naturally salty, the activities of man have increased the salinity. The major activity is irrigation, through two mechanisms. One is the diversion of water for irrigation, which allows increased evaporation in the fields, and irrigation water that returns to the river with more concentrated salt content. The other is the depletion of freshwater aquifers through pumping. The Pecos watershed overlays both saline and freshwater aquifers, both of which have historically contributed to the riverflow. Man has ignored the saline aquifers, but heavily pumped the freshwater aquifers, reducing their contribution to the river, but not the contribution of the saline aquifers.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://twri.tamu.edu/reports/2008/tr315.pdf&quot; rel=&quot;noreferrer&quot;&gt;This report&lt;/a&gt; is also good, and goes into much detail about the sources, both natural and human, of the Pecos River's salinity.&lt;/p&gt;&#xA;&lt;p&gt;The upper reaches of the Red River in Texas overlay the same formation that creates saline conditions in the Pecos River. The streams and springs that form the source of the Red River are quite salty, and it is only further downstream, after dilution from other freshwater inputs that the Red River loses its high salinity. As &lt;a href=&quot;https://pubs.usgs.gov/fs/fs-170-97/FS_170-97.htm&quot; rel=&quot;noreferrer&quot;&gt;this USGS fact sheet&lt;/a&gt; says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Salinity is the greatest limitation on water use in the Red River&#xA;Basin and is largely the result of naturally occurring salt springs in&#xA;parts of the upper reaches of the basin (Keller and others, 1988). The&#xA;salt sources contribute water with large (relative to potable water)&#xA;concentrations of dissolved solids, principally chloride. At certain&#xA;times and locations, the salinity of streams in the basin exceeds that&#xA;of seawater (Keller and others, 1988).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3Xj23.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3Xj23.jpg&quot; alt=&quot;Salty bed of Little Red River, a tributary of Red River, Texas (Wikipedia)&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Salty bed of Little Red River, a tributary of Red River, Texas (Wikipedia)&lt;/p&gt;&#xA;&lt;p&gt;There are salty rivers in various places on Earth, but they are primarily found in arid regions. Since much of their flow comes from groundwater (which may be much saltier than rainfall), and evaporation from the river surface is high, it seems reasonable to me that they would be more likely to be saltier than rivers in wet regions that have large contributions from rainfall, and less net evaporation. These factors are magnified by human activities such as irrigation which happens in arid regions, but less so in areas of ample rainfal.&lt;/p&gt;&#xA;" OwnerUserId="6696" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-11-29T20:30:04.293" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8828" PostTypeId="1" AcceptedAnswerId="8830" CreationDate="2016-10-05T19:35:25.337" Score="5" ViewCount="121" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sY4sF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sY4sF.png&quot; alt=&quot;clarification-this is an example and it is the AOD time serie at a longitudinal segment (AOD VERSUS latitude) in the atlantic next to the africa during 15 years (2000-2014) using the combined dark target and deep blue data. I do not understand the white areas (between 20 and 22°N)that sistematically appear in the AOD field. thank you for answer&quot;&gt;&lt;/a&gt;I have a doubt about the 'white spaces' in the maps from satellite. For example, for the atlantic areas I have plotted AOD and appear many areas where sistematically do not have any data (white spaces). So I want to know why that happens or which factors are behind that. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;thank you for your answer &lt;/p&gt;&#xA;" OwnerUserId="6720" LastEditorUserId="6720" LastEditDate="2016-10-06T00:04:44.713" LastActivityDate="2016-10-06T00:04:44.713" Title="doubt about the 'white spaces' in the maps from satellite" Tags="|atmosphere|planetary-science|weather-satellites|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8830" PostTypeId="2" ParentId="8828" CreationDate="2016-10-05T21:23:30.650" Score="4" Body="&lt;p&gt;Expect every daily retrieval of AOD to have many missing pixels, mostly where clouds appear.  Data is removed when the quality assurance flags do not meet some minimum criteria.  This can happen when the retrieval is contaminated (e.g. from clouds or sun glint on the surface).  If you are interested, you can obtain raw level-1 and level-2 data with all data, including arrays for quality assurance flags.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There will also be systematic gaps in the data where the satellite had no coverage.  Polar orbiting satellites will get complete coverage near the poles, but widening gaps will appear the closer you get to the equator.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2016-10-05T21:23:30.650" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8833" PostTypeId="1" AcceptedAnswerId="8834" CreationDate="2016-10-06T09:08:29.243" Score="3" ViewCount="60" Body="&lt;p&gt;I looking for a catalog (ideally in a ASCII file) of the major tectonic faults on earth, in order to plot some of them on a map&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any suggestion ?&lt;/p&gt;&#xA;" OwnerUserId="6585" LastActivityDate="2016-10-06T19:40:02.137" Title="tectonic faults catalog for plot" Tags="|plate-tectonics|tectonics|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8834" PostTypeId="2" ParentId="8833" CreationDate="2016-10-06T13:26:08.120" Score="3" Body="&lt;p&gt;A good database of tectonic plates is available at the &lt;a href=&quot;http://ig.utexas.edu/marine-and-tectonics/plates-project/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Institute for Geophysics of the University of Texas&lt;/a&gt;. The database includes &lt;a href=&quot;http://www-udc.ig.utexas.edu/external/plates/0.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;present conditions&lt;/a&gt; and &lt;a href=&quot;http://www-udc.ig.utexas.edu/external/plates/recons.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;past and future conditions&lt;/a&gt;. They provide ASCII files in their &lt;a href=&quot;ftp://ftp.ig.utexas.edu&quot; rel=&quot;nofollow noreferrer&quot;&gt;ftp site&lt;/a&gt;.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/tpnVJ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tpnVJ.jpg&quot; alt=&quot;plates from UTIG&quot;&gt;&lt;/a&gt; &lt;a href=&quot;http://www-udc.ig.utexas.edu/external/plates/0.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another option is the data from Peter Bird at UCLA that he described in his article &lt;a href=&quot;http://dx.doi.org/10.1029/2001GC000252&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;An updated digital model of plate boundaries&quot;, $G^3$, 2003&lt;/a&gt;. He provides the data in ASCII format in their &lt;a href=&quot;http://peterbird.name/oldFTP/PB2002/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ftp site&lt;/a&gt; (they include a &lt;a href=&quot;http://peterbird.name/oldFTP/PB2002/2001GC000252_readme.txt&quot; rel=&quot;nofollow noreferrer&quot;&gt;readme&lt;/a&gt; file with the description of the data). &lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2016-10-06T19:40:02.137" LastActivityDate="2016-10-06T19:40:02.137" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8835" PostTypeId="2" ParentId="8806" CreationDate="2016-10-06T13:37:51.407" Score="8" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Werra&quot; rel=&quot;noreferrer&quot;&gt;Werra&lt;/a&gt; – a natural river – had and up to a certain degree still has at least a brackish water body. A portion of the salt content of the river comes from natural leaching, the greater part is passed by nearby potash industry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jEzek.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jEzek.jpg&quot; alt=&quot;Heringen&quot;&gt;&lt;/a&gt;&#xA;(&lt;a href=&quot;https://www.google.com/maps/place/50%C2%B053&amp;#39;14.0%22N+10%C2%B000&amp;#39;20.0%22E/@50.8967781,10.0000872,9781a,20y,46.55h/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d50.887222!4d10.005556&quot; rel=&quot;noreferrer&quot;&gt;Heringen with the Werra between mine and city&lt;/a&gt;. The picture was shot from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Monte_Kali_(Heringen)&quot; rel=&quot;noreferrer&quot;&gt;Monte Kali&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The legal threshold value in the 1940s was a salinity of about 0.5%. The value was often exceeded. Later in the 1960's the underground dumping of the by-products was ceased and all the brine ended in the Werra. The salinity rose up to 4.0%.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ocean like salinity terminated the former (almost) freshwater habitat and changed it to brackish water habitat with a very low  biodiversity: e.g. only one invertebrate (of former 60 -100) survived and two invertebrate halophile aliens were introduced.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;After the German reunification potash mining (a lot of mines were in the former GDR) declined and stricter limits were introduced. The salinity limits now are ~0.5 % and will be reduced to ~0.3% until 2019. The actual salinity seems to be ~0.33% (Source: &lt;a href=&quot;http://www.bund.net/fileadmin/bundnet/pdfs/wasser/lebendige_fluesse/20111108_Wasser_WerraVersalzung_Gutachten.pdf&quot; rel=&quot;noreferrer&quot;&gt;Werra-Versalzung Gutachten p44/45&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="5282" LastEditorUserId="5282" LastEditDate="2016-10-07T16:43:51.187" LastActivityDate="2016-10-07T16:43:51.187" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8836" PostTypeId="1" AcceptedAnswerId="12592" CreationDate="2016-10-06T13:46:58.273" Score="3" ViewCount="131" Body="&lt;p&gt;Despite the background information coming from another body besides the Earth, the terms I would like to understand are historically geophysical in nature.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Background:&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;I just read today's news &quot;&lt;a href=&quot;http://phys.org/news/2016-10-saturn-moon-dione-harbors-subsurface.html&quot; rel=&quot;nofollow&quot;&gt;Saturn's moon Dione harbors a subsurface ocean&lt;/a&gt;&quot; at Phys.org and this seems to bring the number of sub-surface oceans in the Solar System to about six (the number might vary depending on the level of certainty). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This news about Saturn's moon &lt;a href=&quot;https://en.wikipedia.org/wiki/Dione_(moon)&quot; rel=&quot;nofollow&quot;&gt;Dione&lt;/a&gt; comes from a model which uses gravitational data from recent flyby's of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cassini%E2%80%93Huygens&quot; rel=&quot;nofollow&quot;&gt;Cassini&lt;/a&gt; spacecraft. The model is simultaneously applied to another one of Saturn's moons &lt;a href=&quot;https://en.wikipedia.org/wiki/Enceladus&quot; rel=&quot;nofollow&quot;&gt;Enceladus&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Question:&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;My question is about the terms in the abstract of the recently published paper on the subject in &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2016GL070650/abstract;jsessionid=0CD5871EC980CE4699D8E8CC9552A955.f01t04&quot; rel=&quot;nofollow&quot;&gt;Geophysical Research Letters&lt;/a&gt; and my question is limited to these terms which I believe come from Earth Science and apply to the understanding of the Earth's crust &lt;s&gt;floating on it's magma &quot;ocean&quot;&lt;/s&gt; interaction with the hot and slightly viscous mantle below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is an &lt;em&gt;isostatic model&lt;/em&gt; and what is &lt;em&gt;deviatoric stress&lt;/em&gt; in the context of geophysics?&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Enceladus' gravity and shape have been explained in terms of a thick isostatic ice shell floating on a global ocean, in contradiction of the thin shell implied by librations. Here we propose a new &lt;strong&gt;isostatic model minimizing crustal deviatoric stress&lt;/strong&gt;, and demonstrate that gravity and shape data predict a 38 ± 4km-thick ocean beneath a 23 ± 4km-thick shell agreeing with – but independent from – libration data. Isostatic and tidal stresses are comparable in magnitude. South polar crust is only 7 ± 4km thick, facilitating the opening of water conduits and enhancing tidal dissipation through stress concentration. Enceladus' resonant companion, Dione, is in a similar state of minimum stress isostasy. Its gravity and shape can be explained in terms of a 99 ± 23km-thick isostatic shell overlying a 65 ± 30km-thick global ocean, thus providing the first clear evidence for a present-day ocean within Dione.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2016-10-06T23:26:19.390" LastActivityDate="2017-11-01T23:40:22.607" Title="Need help understanding what an &quot;isostatic model minimizing crustal deviatoric stress&quot; means" Tags="|plate-tectonics|mantle|crust|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8837" PostTypeId="1" AcceptedAnswerId="8848" CreationDate="2016-10-06T15:29:27.653" Score="6" ViewCount="524" Body="&lt;p&gt;I randomly had a question pop into my head: &quot;Why are oceans salty, but rivers are not?&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This article seems to provide a plausible explanation: &lt;a href=&quot;http://oceanservice.noaa.gov/facts/riversnotsalty.html&quot; rel=&quot;noreferrer&quot;&gt;http://oceanservice.noaa.gov/facts/riversnotsalty.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It basically says:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Rain keeps putting fresh water into the rivers, which is why they aren't &quot;salty&quot;.&lt;/li&gt;&#xA;&lt;li&gt;Rivers, as they flow, pick up sediment from the earth and push that into the oceans.  It's more or less this sediment that makes the oceans taste &quot;salty&quot;.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;That leads me to my question:&lt;/strong&gt;  Is the ocean really &quot;rising&quot;, or is the floor just getting &quot;thicker/higher&quot;.  The article states that millions of tons of sediment is being deposited on the ocean floor every year.  Most people say/believe that melting ice is causing the ocean level to rise.  I'm not trying to counter that, but couldn't all that sediment be a significant factor as well?  i.e. Maybe the ocean level isn't &quot;rising&quot; as much as we believe, but, rather, the water is getting displaced by all that sediment?&lt;/p&gt;&#xA;" OwnerUserId="6731" LastActivityDate="2018-03-03T18:23:44.007" Title="Ocean level rising, or the floor getting higher?" Tags="|ocean|climate-change|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8838" PostTypeId="1" CreationDate="2016-10-06T15:33:18.087" Score="9" ViewCount="608" Body="&lt;p&gt;&lt;strong&gt;Summation:&lt;/strong&gt; Local cooling climate changes, since the last ice age seem relatively common and all seem to cause significant harm to human population. But I can't find instances of the reverse, warming climate changes that caused harm. If anything, the correlation seems reversed, warming climate change brings benefits. (Note: Droughts to not indicate warming.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any known or suspected historical i.e. Holocene climatic warming associated with negative impacts on human populations?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Details:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This one caught me by surprise. I had assumed episodes of destructive warming would be common and well documented.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am reading &#xA;&lt;a href=&quot;https://www.scribd.com/doc/233092894/The-Great-Famine-Northern-Europe-in-the-Early-Fourteenth-Century#&quot; rel=&quot;noreferrer&quot;&gt;The Great Famine: Northern Europe in the Early Fourteenth Century&lt;/a&gt; by Medieval scholar &lt;a href=&quot;https://www.scribd.com/author/242832594/William-Chester-Jordan&quot; rel=&quot;noreferrer&quot;&gt;William Chester Jordan.&lt;/a&gt; The book regards a massive famine that hit Western/Northern Europe 1315-1322. Until recently, the Great Famine was overshadowed by the &quot;Great Mortality&quot; pandemic episode of the Black Death which struck 1346–53. Computerization of period sources in the last 20 years has allowed researchers to correlate much wider patterns than in the past and the event is now know to have been much wider in area and of longer duration than realized. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Besides the scale, what makes the Great Famine possibly unique is that it was caused by three or more years of continuous rain i.e. it rained roughly 9 out of every 10 days, Spring, Summer and Fall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rain essentially drowned the seedlings in spring, the roots in summer, then rotted crops in the fields towards fall. In addition, the extraordinary wet conditions caused a &quot;murine&quot; an outbreak of diseases in almost all domestic animals but particularly cattle e.g. Hoofed animals often had their hooves (which are just giant toenails) so constantly immersed that eventually they just sloughed off. Other's died of water born illnesses. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was intrigued by the event because I assumed before reading the book that the catastrophe must have been a localized example of the &quot;The Big Sog&quot; outcome predicted by some climate models in which the increase in world temperatures leads to significantly higher humidity world wide which causes incessant rain. I knew that the effected years fell into the Medieval Climate Anomaly which definitely represented a sustained warming in Europe and likely most of the Northern Hemisphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the chronicles, various accounting records and climate proxies all show a dramatic cooling, with brutal winters of intense cold, deep snows and ice packs forming on the Northern shores Europe. The overall climate/weather-patterns had shown a general but widely oscillating cooling pattern since the late-1200s. After the 1320s, Europe (at least) slipped into &quot;The Little Ice Age&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It was this cooling that allowed the Black Death to spread by altering the way in which the Y. Pestis bacteria clump inside the fleas that carry it. The same dynamic of cooling, rain, harsh winters and plague outbreak, occurred in 542 in the Mediterranean world during when several years of cooling probably caused by a volcanic eruption, reduced harvest, drove nomads southward and nearly destroyed the Byzantine and &lt;a href=&quot;https://en.wikipedia.org/wiki/Sasanian_Empire&quot; rel=&quot;noreferrer&quot;&gt;Sasanian&lt;/a&gt; empires. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;During the Medieval Anomaly it appears that the climate of MesoAmerica, North America west of the Sierras grew dryer with years and possibly decades of drought conditions. However, the overall temperatures seemed to have cooled. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Drought conditions can &lt;strong&gt;&lt;em&gt;cause&lt;/em&gt;&lt;/strong&gt; higher peak daytime temperatures because of the loss of cloud cover, but these peaks are offset by nighttime lows by the same mechanism, just as occurs in deserts. The actual heat content of the atmosphere, its enthalpy, which drives weather and climate, actually decreases because most of the heat is held in the atmospheric humidity and the biomass. It's easy to see how cooling can cause droughts. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm looking for the kind of increase in enthalpy predicted for world wide by current climate models.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If such events are unknown, that would be a separate question.&lt;/p&gt;&#xA;" OwnerUserId="652" LastEditorUserId="595" LastEditDate="2016-10-13T12:44:04.293" LastActivityDate="2020-11-03T03:05:22.780" Title="Any historical examples of destructive climate warming?" Tags="|climate-change|paleoclimatology|rainfall|drought|" AnswerCount="6" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8839" PostTypeId="2" ParentId="8836" CreationDate="2016-10-06T15:46:00.063" Score="3" Body="&lt;p&gt;&lt;em&gt;Isostatic&lt;/em&gt; means the equilibrium between the components of the crust in regards to their vertical movement owing to differences in density. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Deviatoric stress&lt;/em&gt; is the kinda sideways stress that particles in a larger system under stress, impose on each other. It's what keeps objects from crumbling to dust when exert vertical stress on them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, there model simulates the vertical stress on the crust more than it does the horizontal stresses. Enceladus is a puzzle because it's squished down at the poles much more than any other known moon or planet.&lt;/p&gt;&#xA;" OwnerUserId="652" LastActivityDate="2016-10-06T15:46:00.063" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8840" PostTypeId="2" ParentId="8798" CreationDate="2016-10-06T20:15:48.500" Score="1" Body="&lt;p&gt;There are a vast number of hypothetical minerals that will not form or persist in the presence of water, particularly liquid water. Since the Earth's mantel and crust are sodden compared to Mercury, Venus and maybe Mars, we might find a lot of new minerals once we start routing around. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is one in particular that IIRC the rovers were configured to find. I'll see if I can snag a reference. &lt;/p&gt;&#xA;" OwnerUserId="652" LastActivityDate="2016-10-06T20:15:48.500" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8841" PostTypeId="2" ParentId="8806" CreationDate="2016-10-06T22:18:07.400" Score="12" Body="&lt;p&gt;There are salt water rivers in different places of the world where ground water flows in contact with salt layers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a river in Catalonia named &lt;a href=&quot;https://ca.wikipedia.org/wiki/Ribera_Salada&quot; rel=&quot;noreferrer&quot;&gt;Ribera Salada&lt;/a&gt; (meaning salty river in Catalan). My translation from Catalan Wikipedia:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It gets its name because one of its originating currents - Fred river - comes from sources in Triassic lands with a high content of salts. The river is salty enough that its waters had been used for long time in Cambrils to obtain salt.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, Ribera Salada is actually salty just in part of its course, since mixing with other freshwater currents makes it brackish or nearly freshwater.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4aXQF.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4aXQF.jpg&quot; alt=&quot;Ribera Salada in Castellar de la Ribera. &quot;&gt;&lt;/a&gt;&#xA;Image from Wikimedia Commons. &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Ribera_Salada_-_(%C3%80rea_Recreativa_de_Castellar_de_la_Ribera).JPG&quot; rel=&quot;noreferrer&quot;&gt;Credits here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6550" LastActivityDate="2016-10-06T22:18:07.400" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8842" PostTypeId="2" ParentId="4568" CreationDate="2016-10-07T09:07:50.540" Score="2" Body="&lt;p&gt;Surace,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are two references:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://www.iup.uni-heidelberg.de/institut/forschung/groups/ts/soil_physics/research/pms/cracks&quot; rel=&quot;nofollow&quot;&gt;http://www.iup.uni-heidelberg.de/institut/forschung/groups/ts/soil_physics/research/pms/cracks&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Coupling analysis of pattern formation in desiccation cracks, [2016, Sayako Hirobe and Kenji Oguni]&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Best,&#xA;Jannes&lt;/p&gt;&#xA;" OwnerUserId="6740" LastActivityDate="2016-10-07T09:07:50.540" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8843" PostTypeId="2" ParentId="8806" CreationDate="2016-10-07T11:14:40.887" Score="10" Body="&lt;p&gt;Here in Western Australia we have many salt water streams running through farmland affected by dry land salinity. It's a huge problem where land cleared for agriculture has experienced rising water tables effectively bringing salt to the surface. This salt is washed into the creeks by rain and these streams are essentially salt saturated - far saltier than seawater. The streams generally only flow during winter though. Huge tracts of land are no longer arable because of the extreme salinity.&lt;/p&gt;&#xA;" OwnerUserId="6741" LastActivityDate="2016-10-07T11:14:40.887" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8844" PostTypeId="2" ParentId="8789" CreationDate="2016-10-07T13:03:04.200" Score="4" Body="&lt;p&gt;To my understanding, the question refers to studies which aim to estimate pollutant emission fluxes using satellite retrievals of atmospheric constituents. Mathematically, this means estimating the forcing term in an advection-diffusion-reaction system given a set of tracer observations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How well you can localize the emissions depends on the pollutant: for something shortlived, like NO2, a given observation will be influenced by a relatively small area, while for a long-lived pollutant (say CO) the effective resolution would be much lower. For long-lived pollutants, the problem is not well posed and needs to be regularized in some way. Typically, instead of reconstructing the emission from a scratch, you try to just refine an existing emission inventory. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The issues you mention regarding model errors are real and certainly do introduce biases in any emission estimates based on satellite products. This is quite well understood by people working on the field, but the difficulty is in quantifying the errors that are due to model uncertainty.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How to generate a relative precise relationship between satellite data&#xA;  and source emission in consideration of these doubts?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Opinions vary. In my experience, few scientists believe that satellite-based emissions could replace traditional emission inventories. On the other hand, for many areas and pollutants, the regular emission inventories also involve a lot of extrapolation. Ultimately, the question is whether the inverse modeling can deliver some useful added value compared to the existing inventories.&lt;/p&gt;&#xA;" OwnerUserId="859" LastActivityDate="2016-10-07T13:03:04.200" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8845" PostTypeId="1" AcceptedAnswerId="8851" CreationDate="2016-10-07T18:42:37.723" Score="6" ViewCount="145" Body="&lt;p&gt;Somewhere I've read it is in the order of some tens of billions of years, but unfortunately I can't find any reference with it in Google.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suspect, the losses are coming mainly from analyzing the statistical distribution of the upper atmosphere, extending with the interaction of the Solar Wind. The result is probably a finite element model and not an analytical solution. Am I right? What is the result?&lt;/p&gt;&#xA;" OwnerUserId="6016" LastEditorUserId="6016" LastEditDate="2021-04-02T19:33:48.623" LastActivityDate="2021-04-02T19:33:48.623" Title="What is the characteristic time of the loss of the Earth atmosphere, how can it be calculated?" Tags="|atmosphere|atmosphere-modelling|moon|upper-atmosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="8846" PostTypeId="1" CreationDate="2016-10-07T19:15:19.840" Score="2" ViewCount="135" Body="&lt;p&gt;Is it possible that dolomitization occur in deep-water environment? &#xA;If it possible, how?&lt;/p&gt;&#xA;" OwnerUserId="5578" LastActivityDate="2016-10-09T22:26:25.910" Title="Dolomite in deep-water environment" Tags="|geochemistry|sedimentology|carbonate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8848" PostTypeId="2" ParentId="8837" CreationDate="2016-10-08T04:43:17.777" Score="7" Body="&lt;p&gt;In a geologically static world you might have a point. Erosion would wear down the land surface, depositing the sediment in the ocean - where 'Archimedes principle' would apply, and seas level would rise by displacement. There are two main reasons why this doesn't account for the rate of sea level rise that we are seeing: plate tectonics and observed rates. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth is a tremendously dynamic environment in which plate tectonics drive an approximate balance between crustal destruction by erosion and subduction, as against freshly generated land at 'constructive margins'. This 'wobbly balance' has been going  for the past 3+ billion years, and is likely to continue for several billion years more. The balance of rise and fall in sea level averages close to zero but has positive and negative anomalies over time. In all cases, fluctuations are slow - in the order of millions of years (excluding the much larger short-term fluctuations caused by ice ages). So for all practical purposes the base-line is 'zero change', upon which is superimposed the effects of sea level rise as we exit the last ice age, i.e. the last 12000 years and continuing. On top of that is the recent effect of human-induced climate change. Let us consider these  rates compared to the hypothetical rate of erosion and sea level rise in a static world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During the 20th century, sea level rise was estimated from tide-gauges, which raises the problem of 'are we measuring rising sea or sinking land?'  For the last decade or so we have been able to measure absolute mean sea levels by satellite. That is, independent of land levels. Now we can re-evaluate old data, and come up with 'real' average rates of rising sea level. They turn out to be about 2.5 +/- 1.5 mm/year for most of the last century. Now they have accelerated to more than twice that amount. See, for example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.climate.gov/news-features/understanding-climate/climate-change-global-sea-level&quot; rel=&quot;noreferrer&quot;&gt;https://www.climate.gov/news-features/understanding-climate/climate-change-global-sea-level&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the &lt;em&gt;global average&lt;/em&gt;, and yes, there are all manner of positive and negative anomalies. Now consider sediment displacement. Measuring the global sediment flux from rivers to oceans is extraordinarily difficult, for reasons which would take several pages to explain. But of the diverse range of estimates the consensus seems to be between 20 and 60 Gtonnes per year for the world's major rivers. Leaning towards the upper bound, and adding in a factor for the minor rivers, and assuming an average sediment density of about 2.5, we arrive at about 40 billion cubic metres of sediment entering the oceans each year. There are about 360 million square kilometres of ocean, so on average, the annual increase in ocean sediment is about 1.1 mm. In reality, this is an upper bound with the a more realistic estimate being about 0.6 mm. So, even without taking oceanic subduction into account, the observed sea level is at least an order of magnitude more than can be accounted for by sediment displacement. Or to answer your question, no, the ocean floor isn't rising at any rate that we can measure. Conversely, sea level &lt;em&gt;is&lt;/em&gt; rising at a rate that is consistent with thermal expansion of the ocean surface, combined with nett global ice melt.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-10-08T04:43:17.777" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8849" PostTypeId="2" ParentId="8846" CreationDate="2016-10-08T04:57:37.883" Score="2" Body="&lt;p&gt;For dolomitization to occur, either by primary precipitation or by diagenesis, requires a highly magnesian environment and alkaline conditions. The most favourable environment for this to occur is by deeply circulating seawater into the upper mantle which underplates oceanic crust. I don't mean the hydrothermal circulation around spreading centres (which is acidic), but the relatively mild temperatures of submarine groundwater. In the occasional cases where this upper mantle is obducted onto land as ophiolites you will find magnesite predominating, with minor huntite, and dolomite of various early and late-stage paragenesis. The process of serpentinization releases aqueous magnesium, and reaches pHs as high as 12. Moreover, the associated dolomitization starts in the marine environment, and continues after the ophiolite becomes land. For example, you can go to the Semail ophiolite in Oman and find primary and secondary dolomite precipitating - along with occasional metastable huntite and hydroxycarbonates. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2016-10-09T22:26:25.910" LastActivityDate="2016-10-09T22:26:25.910" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8851" PostTypeId="2" ParentId="8845" CreationDate="2016-10-08T06:49:57.120" Score="4" Body="&lt;p&gt;Even in the exosphere, at 1800 deg centigrade, the only components of the Earth's atmosphere that can currently attain escape velocity are hydrogen (3 kg per sec), and and helium (next to nothing). The notion that the Earth's atmosphere would be stripped away by solar wind but for the protective magnetic shield, is a myth. So there is no 'characteristic time of loss of the Earth's atmosphere' in the sense of slow decay. There &lt;em&gt;is&lt;/em&gt; certainty that, as the sun approaches the red giant stage, several billion years from now, there will be catastrophic heating of the atmosphere such that oxygen and nitrogen will be stripped away, leaving Earth to overheat in runaway carbon-dioxide. Unless, that is, if gravitational mayhem, caused by galactic collision with Andromeda, flings Earth substantially further from the sun. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oxygen, nitrogen and inert gasses &lt;em&gt;can&lt;/em&gt; escape from bodies the size of the moon, Venus and Mars because the thermal process, 'Jeans Escape', in less massive bodies incurs substantially lower escape velocities. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-10-08T06:49:57.120" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8852" PostTypeId="2" ParentId="8806" CreationDate="2016-10-08T10:29:51.983" Score="15" Body="&lt;p&gt;I live near a river named Salz, flowing both warm and salty on the north slope of the Pyrenees south of Carcassonne. In historical times it was boiled dry for salt. See &lt;a href=&quot;http://www.odeaanaude.eu/catalogaude2/les-sources-de-salz-sougraigne-p-928.html?language=en&quot; rel=&quot;noreferrer&quot;&gt;Les Sources de Salz&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6750" LastEditorUserId="6" LastEditDate="2016-10-13T10:48:52.387" LastActivityDate="2016-10-13T10:48:52.387" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8854" PostTypeId="1" CreationDate="2016-10-08T20:08:57.810" Score="0" ViewCount="186" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Korzi.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Korzi.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What does the bottom picture represent when it says Lower Emissions (B1) and Higher Emissions (B2)?&lt;/p&gt;&#xA;" OwnerUserId="6754" LastActivityDate="2016-10-08T22:02:21.187" Title="What does this diagram mean?" Tags="|climate-change|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8855" PostTypeId="1" AcceptedAnswerId="8857" CreationDate="2016-10-08T20:39:03.353" Score="3" ViewCount="68" Body="&lt;p&gt;Autoregressive models (AR) are extensively used to understand the behavior of streamflow. The literature abounds with examples of AR models from different families applied &quot;everywhere&quot; to fully understand how streamflow changes throughout the hydrologic year. One particularly well accepted model is the periodic autoregressive model, as in Hipel and McLeod (1984).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far, from all I've ever read, all &lt;strong&gt;streamflow&lt;/strong&gt; AR models will have a &lt;strong&gt;signficant first order lag&lt;/strong&gt;. That is, when one calculates the PACF to find the order p of the model, p will assume a value of 1, at least. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any known case &lt;em&gt;registered in the literature&lt;/em&gt; of an AR streamflow model of order 0, i.e., AR(0) for streamflow? That is, is there a possible way that the &quot;yesterday's flow&quot; won't explain the &quot;today's flow&quot;? &lt;/p&gt;&#xA;" OwnerUserId="5301" LastEditorUserId="5301" LastEditDate="2016-10-09T19:47:32.777" LastActivityDate="2016-10-09T22:47:00.560" Title="Is it possible to have an AR(0) for streamflow?" Tags="|models|hydrology|rivers|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8856" PostTypeId="2" ParentId="8854" CreationDate="2016-10-08T22:02:21.187" Score="5" Body="&lt;p&gt;The B1 and A2 referenced in the chloropleth maps are referring to the emissions scenarios that were presented alongside the IPCC's Third Assessment Report (TAR) in the Special Report on Emissions Scenarios (SRES). These scenarios referred to the rate, timelines, and total volume of carbon and other greenhouse emissions that might be realized by the end of the 21st century.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These were several scenarios (A2, A1B, B1, etc.) that were used with the aid of climate models to determine what the possible climate change impacts of pursuing &quot;Business as Usual&quot; (A2), to rapidly reducing emissions and stabilizing climate (B1). While some researchers still use these emissions scenarios and the climate models that were presented with them for some predictions, most climate scientists now refer to the more recent Fifth Assessment Report's (AR5) Representative Concentration Pathway Scenarios (RCP).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For more information: &lt;a href=&quot;http://www.nature.com/nature/journal/v463/n7282/full/nature08823.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.nature.com/nature/journal/v463/n7282/full/nature08823.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5536" LastActivityDate="2016-10-08T22:02:21.187" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8857" PostTypeId="2" ParentId="8855" CreationDate="2016-10-09T22:24:42.803" Score="1" Body="&lt;p&gt;Yesterday's baseflow always influences today's baseflow because the natural recession has an exponential recession constant measured in days to months. This is evident in all but the smallest of catchments. In fast-draining very small catchments, where the time of concentration is typically measured in minutes, the antecedent conditions have little bearing on flow. They probably aren't reported in the literature, because who cares about the flow variation in very small catchments? So technically, yes, it is possible to have AR(0), but it is of no serious interest. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-10-09T22:24:42.803" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8858" PostTypeId="2" ParentId="8855" CreationDate="2016-10-09T22:47:00.560" Score="4" Body="&lt;p&gt;Autoregressive models are mathematical models, and like all models, are based on a conceptual model of the system. The conceptual model is that prior flow is a parameter in prediction of current flow. So it doesn't really make sense to have a model where it does not do so. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore it is difficult to conceive of a natural system where prior flow is not a predictor. This is where I disagree with Gordon's answer. Even in small catchments, prior flow is a good surrogate for the physical conditions that contribute to flow. The conditions include precipitation history, soil moisture, filling of depressions so flow can accumulate, capacity for trees to intercept precipitation (are the leaves already wet), water-table stream connectivity, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you don't see a relationship to prior flow in small catchments, that may just mean your daily timestep is too large. I care about the flow variation in very small catchments and monitor the flow on 30-minute intervals.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2016-10-09T22:47:00.560" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8860" PostTypeId="1" AcceptedAnswerId="8868" CreationDate="2016-10-10T09:47:02.630" Score="5" ViewCount="4013" Body="&lt;p&gt;I want to convert OMI AURA data on NO2 column amounts in molecules/cm2 into ppm for comparison purposes with other literature. Can it be done? Is there a standard way of doing it? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I looked into the &lt;a href=&quot;http://disc.sci.gsfc.nasa.gov/Aura/data-holdings/OMI/documents/v003/OMNO2_readme_v003.pdf&quot; rel=&quot;nofollow&quot;&gt;readme file&lt;/a&gt; but could not find an answer.&lt;/p&gt;&#xA;" OwnerUserId="6764" LastEditorUserId="543" LastEditDate="2016-10-11T05:04:00.573" LastActivityDate="2021-06-30T10:56:51.943" Title="Convert OMI NO2 Vertical Column Density (molecules/cm^2) into Mixing Ratio (ppm)" Tags="|remote-sensing|air-pollution|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8861" PostTypeId="1" CreationDate="2016-10-10T12:55:15.947" Score="2" ViewCount="57" Body="&lt;p&gt;Yes this is a bit broader question but I want to know which processes play their role in movement of magma. If one wants to model magma movement through rocks, which processes should one not miss at all and which equations discuss these processes?. As a starter I can that we can use Navier Stokes equations for velocity fields, continuity equation for pressure distribution and etc. &lt;/p&gt;&#xA;" OwnerUserId="5557" LastActivityDate="2016-11-25T16:04:08.000" Title="Which equations describe complete (or near complete) behaviour of magma moving through rocks?" Tags="|numerical-modelling|convection|magmatism|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8862" PostTypeId="2" ParentId="8806" CreationDate="2016-10-10T15:32:29.317" Score="5" Body="&lt;p&gt;Świna (note that while english wikipedia lists it as a river, both german and polish wikipedias are more ambiguous, for example polis wiki descirbes it as  a &quot;strait&quot; of the Baltic sea): &lt;a href=&quot;https://en.wikipedia.org/wiki/%C5%9Awina&quot; rel=&quot;nofollow&quot;&gt;Świna (Wikipedia)&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6766" LastEditorUserId="6093" LastEditDate="2016-10-12T07:55:26.080" LastActivityDate="2016-10-12T07:55:26.080" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8863" PostTypeId="1" CreationDate="2016-10-10T18:02:58.443" Score="3" ViewCount="64" Body="&lt;p&gt;(&lt;a href=&quot;https://earthscience.stackexchange.com/questions/8845/what-is-the-characteristical-time-of-the-loss-of-the-earth-atmosphere-how-can-i&quot;&gt;related question&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am thinking on the Moon if it would have an oxygen atmosphere. What would be the characteristic time of its escape?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although the Moon has a much lower escape velocity as the Earth, it is still around 5 Mach, which results that an air atmosphere there could be relative stable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Somewhere I've read the characteristic time of its escape would be in the order of some ten millions of years. Unfortunately, I can't find my source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, I think a simple boltzman-statistic based model is not enough, because - similarly to the Earth - the processes of the rare gas in the upper atmosphere would be significant.&lt;/p&gt;&#xA;" OwnerUserId="6016" LastActivityDate="2016-10-10T18:02:58.443" Title="What would be characteristic time of the escape of an 1atm air (or oxygene atmosphere) from the Moon?" Tags="|atmosphere|atmosphere-modelling|moon|astronomy|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8864" PostTypeId="2" ParentId="8326" CreationDate="2016-10-10T18:23:07.147" Score="1" Body="&lt;p&gt;Here is an excellent explanation of the math as related the stresses represented by the Moh'r circle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.geology.sdsu.edu/visualstructure/vss/htm_hlp/mor_cir.htm&quot; rel=&quot;nofollow&quot;&gt;http://www.geology.sdsu.edu/visualstructure/vss/htm_hlp/mor_cir.htm&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2016-10-10T18:23:07.147" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8865" PostTypeId="2" ParentId="8861" CreationDate="2016-10-10T19:15:26.087" Score="-1" Body="&lt;p&gt;The equations you are looking for are called the &quot;McKenzie equations&quot;. You should look at the papers of Marc Spiegelman at Columbia University for more information.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2016-10-10T19:15:26.087" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8866" PostTypeId="1" AcceptedAnswerId="8869" CreationDate="2016-10-10T19:37:40.620" Score="2" ViewCount="404" Body="&lt;p&gt;If lava flows back into the ground, would it be called magma again? Is there a difference if it flowed into a new hole vs the flow it came from?&lt;/p&gt;&#xA;" OwnerUserId="6768" LastEditorUserId="2536" LastEditDate="2016-10-11T12:22:14.520" LastActivityDate="2016-10-11T12:22:14.520" Title="If lava flows back into the ground, would it be called magma?" Tags="|geology|volcanology|terminology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8867" PostTypeId="1" CreationDate="2016-10-10T21:07:24.357" Score="1" ViewCount="14" Body="&lt;p&gt;Are there any database for the soils database out there beside NRCS ? I am fully aware that NRCS has their database on their website but I was wondering if there is one that can't i find them ? I am looking more specific for Colorado. They can be either database or geospatial but I prefer them to be the database that goes back to 1990's They need to have mapunit, map name, and their survey areas ?&lt;/p&gt;&#xA;" OwnerUserId="5771" LastActivityDate="2016-10-10T21:07:24.357" Title="Searching for database for Colorado soils that goes back to 1990's" Tags="|soil|database|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8868" PostTypeId="2" ParentId="8860" CreationDate="2016-10-10T23:05:11.773" Score="5" Body="&lt;p&gt;No, you shouldn't really do that.  A vertical column density (VCD) retrieval provides the user with a representation of the total number of molecules over some vertical slice (e.g. the entire troposphere).  A mixing ratio, often defined in parts per million, is meant to express the average number of molecules in a parcel of air.  The problem with converting VCD to ppm is that the troposphere is a whole lot more than &quot;a parcel of air&quot;.  The density of air and mixing ratio of NO2 changes as you move vertically through the atmosphere. So, saying that NO2 has any one mixing ratio through the troposphere is really not appropriate.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are methods you could use to estimate ppm NO2 from VCD (such as inferring mixing ratio from the shape of the &lt;em&gt;a priori&lt;/em&gt; profile), but they would be inherently uncertain for many reasons:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The retrieval of tropospheric NO2 from OMI is not representative of the surface, but rather a well-mixed free troposphere.  &lt;/li&gt;&#xA;&lt;li&gt;The NO2 product is dependent on a global model to subtract the stratospheric contribution.  &lt;/li&gt;&#xA;&lt;li&gt;There are many quality control steps needed for quality assurance, such as accounting for clouds, terrain, surface albedo, detector issues (e.g. striping or row anomalies), etc. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In my experience with OMI tropospheric NO2 data, any expected temporal correlation to daily surface measurements is futile.  You will sometimes find temporal correlation at the seasonal or coarser scale, for what that is worth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Spatial correlation with models and surface monitor networks should be expected, but your results will be highly dependent on your 3D spatial comparison methodology. When comparing to a model, you will want to apply the &quot;averaging kernels&quot; which help to remove the dependence on the &lt;em&gt;a priori&lt;/em&gt; profile of the satellite retrieval.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, OMI tropospheric NO2 data is useful for identifying large emissions sources that are missing from air quality models.   It is also useful for identifying inconsistencies across political borders that appear in air quality models due to old emission inventories (e.g. mixing circa 2006 Canadian emissions with circa 2011 USA emissions).  &lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2016-10-10T23:10:44.380" LastActivityDate="2016-10-10T23:10:44.380" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8869" PostTypeId="2" ParentId="8866" CreationDate="2016-10-11T12:21:36.430" Score="0" Body="&lt;p&gt;Lava is per definition the molten material on the surface or a hardened rock thereof. Lava is expelled from a volcano or fissure. There is a rich vocabulary to describe the composition, formation and processes of lava. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Magma is a melt within the earth. Magma is formed when material reach a temperature for melting or partial melting, e.g. in a magma chamber. Complex high temperature chemistry is used to describe how solid material melts to magma and how it recrystallizes into igneous rocks as a response to temperature, pressure and changed composition. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Magma can originate from any kind of material. The definitions doesn't refer to the composition or origin of the material, but the manifestation. Magma can be melted or partially melted crust, also old volcanic crust, so if old lava somehow re-enters a magma chamber it will be magma. When magma is erupted, it is lava. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is often some confusion, even among professional geologists, about many of the terms we are using. Some terms describes a process and other describes an object. Sometimes we say Upper Jurassic, sometimes Late Jurassic depending on the context. Some terms are historical and some are modern... There are often overlaps. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for any language, it's good to use a broad vocabulary and adopt to the jargon, but most important is to communicate the ideas and observations as clear as possible. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastActivityDate="2016-10-11T12:21:36.430" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8870" PostTypeId="1" CreationDate="2016-10-11T17:03:53.903" Score="1" ViewCount="115" Body="&lt;p&gt;When working with electricity, rubber shoes are recommended because they prevent current from running through your body. &#xA;But I've read that usually the earth is more negative charged than positive. So how is it possible that contacting the earth is dangerous in some situations as it is also negative charged, and when you touch an electrical wire you also get a lot of negative charges (electrons). So in theory, they should repel each other, but apparently, they attract each other to cause a current in a body. How is this possible? Isn't the earth negative charged (most of the times)?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="111" LastEditDate="2016-10-11T18:03:48.873" LastActivityDate="2016-10-16T17:06:44.000" Title="What causes the earth to be a good grounding system?" Tags="|geophysics|electromagnetism|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8871" PostTypeId="1" CreationDate="2016-10-11T20:38:17.230" Score="5" ViewCount="137" Body="&lt;p&gt;It was recently asserted to me that we have no idea what Planet Earth really looks like below our feet. I responded that (mainly oil-industry) seismic data covers a vast area and so actually we have a fairly good idea. The response was that this seismic coverage is very localised in particular areas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some statistics would be useful in this discussion but I'm unable to find any definitive sources.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To be specific, lets assume we are interested in the top 3 kilometers of the crust, and that a minimum 2D seismic spacing of 2 km would be required.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On that basis, what percentage of the earth's surface is covered by reflection seismic data?&lt;/p&gt;&#xA;" OwnerUserId="2921" LastActivityDate="2016-12-12T17:53:52.073" Title="What percentage of the earth's surface is covered by 2D or 3D reflection seismic data?" Tags="|geophysics|seismic|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8873" PostTypeId="2" ParentId="8870" CreationDate="2016-10-11T23:01:28.690" Score="5" Body="&lt;p&gt;The electricity you're talking about is the man-made kind, which is completely independent of any charge the Earth has relative to its atmosphere. Man-made power sources are almost all referenced to the Earth as zero volts, as established by connecting the &quot;ground&quot; to a conductive rod driven into the ground. Each house's electrical system is also grounded in this way. Since earth (lower-case &quot;e&quot;) is at least somewhat conductive (except for perhaps dry sand), if you grab a conductor while standing barefoot on the ground then current will flow through you, through the ground, and then back to the source of electricity and/or your house's local grounding rod. Enough volts, and good enough conduction, and you get hurt or killed. Rubber shoes, rubber gloves, and just plain common sense can prevent this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Again, this has nothing to do with the charge the Earth has relative to its atmosphere, as man-made power is generated referenced to Earth ground; plus, since it's almost always alternating current, the polarity changes 50 to 60 times a second, so any purported existing voltage wouldn't protect you.&lt;/p&gt;&#xA;" OwnerUserId="534" LastEditorUserId="534" LastEditDate="2016-10-13T11:57:05.933" LastActivityDate="2016-10-13T11:57:05.933" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8874" PostTypeId="1" CreationDate="2016-10-12T16:31:28.193" Score="3" ViewCount="469" Body="&lt;p&gt;What is the relation of latent heating and the global circulation of the atmosphere?&#xA;Do you know some references about this relationship?&lt;/p&gt;&#xA;" OwnerUserId="4880" LastActivityDate="2016-10-27T15:19:05.780" Title="Latent heat and global circulation" Tags="|meteorology|atmospheric-circulation|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8875" PostTypeId="1" AcceptedAnswerId="8882" CreationDate="2016-10-12T23:05:42.567" Score="3" ViewCount="395" Body="&lt;p&gt;Modern ERT methods/devices can provide 2D resistivity profiles for some terrain. How accurate are the resistivity values in those profiles?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are these some sorts of apparent resistivities and one should interpret them in a special way or the profile pictures show pretty exact resistivity values in all points?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And if they are not exact then what can cause inaccuracies: buried wires (or other metallic structures), voids etc.?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe some methods/devices are less exact than others?&lt;/p&gt;&#xA;" OwnerUserId="6779" LastActivityDate="2016-10-13T11:43:09.960" Title="How accurate are the resistivity values from the electrical resistivity tomography (ERT)?" Tags="|geophysics|measurements|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8876" PostTypeId="1" CreationDate="2016-10-13T08:32:54.500" Score="3" ViewCount="83" Body="&lt;p&gt;I have some trouble trying to understand, why streams and convections in the outer liquid earth core, coriolis forces etc. would create an electric current?&lt;br&gt;&#xA;Because you probably need an electric potential first and what then is the cause of the electric potential?&lt;br&gt;&#xA;Is it perhaps a property of the earth mantle to have regions that are polarized?&lt;/p&gt;&#xA;" OwnerUserId="6781" LastActivityDate="2017-08-03T22:26:47.947" Title="Where do the electric charge carriers for the current for earth's magnetic field come from?" Tags="|geomagnetism|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8877" PostTypeId="1" CreationDate="2016-10-13T08:37:46.560" Score="6" ViewCount="595" Body="&lt;p&gt;I always thought that the movement of the iron core was caused by the axis of orbit of the Earth. Probably that isn't quite as true as I read, because in the core the iron material undergoes types of swirls. I read that there exists about 6 or 7 swirls in the outer core, with the one under Asia the fastest, creating a bigger magnetic field, and the one under America the least active, giving a weaker magnetic field. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if those swirls underneath the continents are stationary, the current swirls aren't caused by the Earth's orbit axis. Instead the swirls arise due to the cycle of material rising, solidifying, and sinking back to the core. But I'm not sure I understood this well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But nevertheless, isn't the current that causes the magnetic field affected by the Earth's axis (or perhaps the orbit around the sun)?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="6298" LastEditDate="2017-11-02T13:18:38.387" LastActivityDate="2018-02-01T03:49:38.327" Title="How much does the electric current within the Earth' core depend on the axis of the Earth's orbit?" Tags="|geophysics|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8878" PostTypeId="1" AcceptedAnswerId="8880" CreationDate="2016-10-13T09:59:13.257" Score="4" ViewCount="666" Body="&lt;p&gt;Having lived in southern California, I know that some areas on the planet can be absurdly sunny and clear throughout the year, and having lived several other places, I know some areas can be chronically overcast.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The article &lt;a href=&quot;http://www.lightwaveonline.com/articles/2016/10/laser-light-to-launch-space-based-laser-network-for-optical-satellite-as-a-service.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Laser Light to leverage free-space optics in space for Optical Satellite as a Service&lt;/a&gt; describes a proposed group satellites in medium Earth orbit (MEO) that would maintain high speed optical data links with a large number of Earth stations. I did some further reading, and found the map shown below. I assume this is still conceptual and the final ground station locations may be different.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I am wondering, besides that one station in southern California, do these appear to be in meteorologically favorable locations for continuous optical data links to satellites? Are these particularly sunny/clear sky locations?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does a map of clear-sky hours per year - independent of day or night - exist? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As pointed out in &lt;a href=&quot;https://space.stackexchange.com/questions/18610/#comment48710_18610&quot;&gt;this comment&lt;/a&gt; and &lt;a href=&quot;http://www.satellitetoday.com/technology/2014/07/07/laser-light-optical-satellite-test-facility-nears-completion/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; the network can work by reconfiguring depending on atmospheric conditions. But do these appear to be chosen by access to clear skies, or access to fiber networks?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KPRFf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KPRFf.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; Graphic from &lt;a href=&quot;http://www.satellitetoday.com/technology/2015/05/04/the-speed-of-light-laser-light-and-optus-explain-optical-communications-partnership/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Speed of Light: Laser Light and Optus Explain Optical Communications Partnership to Via Satellite Magazine&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2017-04-13T12:58:55.897" LastActivityDate="2016-10-17T12:42:20.757" Title="Have these optical satellite ground station locations been chosen for clear skies?" Tags="|atmosphere|clouds|satellites|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8879" PostTypeId="1" CreationDate="2016-10-13T11:00:41.060" Score="1" ViewCount="590" Body="&lt;p&gt;The continental plates are more or less loose from the oceanic plates which are heavier and of other material (basalt) and because continental plates are lighter they 'float' on top of the oceanic plates. But how did they get there?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know if I'm right that islands like Iceland is made of the oceanicp plate because it is in middle of the oceanic plates? But did all 'countries' start like that? It doesn't seem so as most countries/continents are made of lighter material. So how did that lighter material get on top of the oceanic plate?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The explanation of an other answer was: ' This is because the magma that solidifies to form each of these crusts travels, by partially melting its way up, through different materials and different thicknesses. The consequence of this is that the crust making up the continents is less dense than that making up the bottom of the oceans.'&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does this mean that the magma comming from beneath (hotspot etc.) is getting mixed with different materials? Or is this magma already a mix of different material where the heavier ones would stay more or sink at the bottom of the solidifieing two plates? But what makes the upper one not tight joined or gradually to the one beneath?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="5372" LastEditDate="2016-10-13T15:54:37.470" LastActivityDate="2016-10-14T06:01:58.360" Title="How did the continental plates came above the oceanic plates?" Tags="|geology|" AnswerCount="2" CommentCount="2" FavoriteCount="0" ClosedDate="2016-10-15T18:05:37.140" ContentLicense="CC BY-SA 3.0" />
  <row Id="8880" PostTypeId="2" ParentId="8878" CreationDate="2016-10-13T11:10:55.590" Score="6" Body="&lt;p&gt;Yes, mean cloud cover is routinely measured from satellites.  Like all satellite data (and in fact all measurements), it does have an uncertainty, but for the purpose of this question the satellite product of mean cloud coverage is good enough.  Personally, I would hesitate to trust the data at very high latitudes with frequent cover of snow or ice, because those are hard to distinguish from clouds with any form of passive down-looking remote sensing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The figure below is &lt;a href=&quot;http://www.esa.int/Our_Activities/Observing_the_Earth/Space_for_our_climate/Highlights/Cloud_cover&quot; rel=&quot;nofollow noreferrer&quot;&gt;released by ESA&lt;/a&gt; and derived from the MERIS and AATSR instruments on the former ENVISAT satellite.  Although the caption does not specify, I suspect that it uses visible channels and that it therefore only relates to &lt;em&gt;daytime&lt;/em&gt; cloudiness. It would be interesting to see how it compares to 24-hour cloud cover!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NMrnn.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NMrnn.jpg&quot; alt=&quot;Mean cloud cover, ESA&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Full image caption and credit:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Global annual mean cloud cover derived from three years (2007–09) of Envisat data. The map shows areas with little to no cloud coverage (blue) as well as areas that are almost always cloudy (red). Clear skies are immediately visible over deserts (such as the Sahara, Namib and over the Atacama). Regions with constant high-pressure systems are detectable, such as the Pacific. On the other hand, the North Atlantic Ocean in the mid-latitudes is mostly covered with clouds, where storms develop. The UK is often cloudy, whereas the Mediterranean shows sunny skies.&#xA;  Data from both the MERIS and AATSR instruments on Envisat were used.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Credits: ESA/Cloud–CCI&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(On behalf of ESA and the Cloud-CCI I would like to apoligise for the &lt;a href=&quot;https://github.com/djoshea/matlab-utils/blob/master/libs/perceptuallyImprovedColormaps/Rainbow%20Color%20Map%20-Still-%20Considered%20Harmful.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;poor choice of colourmap&lt;/a&gt;, but this figure predates the time at which many of us were educated on its poor suitability)&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2016-10-13T11:23:35.773" LastActivityDate="2016-10-13T11:23:35.773" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8881" PostTypeId="2" ParentId="8879" CreationDate="2016-10-13T11:31:06.227" Score="0" Body="&lt;p&gt;If I had to guess, I'd attribute the difference to gravitational separation - as you said, continental crust is less dense than oceanic crust. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suppose chemically different magmas would seperate in a similar way.... Your question is a little difficult to understand sorry..!&lt;/p&gt;&#xA;" OwnerUserId="6181" LastActivityDate="2016-10-13T11:31:06.227" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8882" PostTypeId="2" ParentId="8875" CreationDate="2016-10-13T11:43:09.960" Score="0" Body="&lt;p&gt;Inaccuracies are inherent based on a wide range of variables. In particular, the array type, as well as the inversion will affect the resistivity of any layer or body. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Interpreting data based purely on apparent resistivity isn't a good idea at all! You should always try to invert the data to produce realistic conductivity distributions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The inaccuracies are caused by the path of the current through the Subsurface. This is why the array will affect the final result (different configurations drive current in different ways). Something unusually conductive will divert current towards the body, while resistive bodies will divertv away.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To better estimate the Subsurface resistivity, you can constrain the inversion with prior knowledge. For example, sharp high contrast boundaries, which can affect the recovered values quite significantly, can be incorporated into most inversion algorithms to (usually) enhance the accuracy of the result.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer your question, the inaccuracy is a product of the physics - instrumentation can only do so much before the physics kicks in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this helps! (Please correct me if/where I'm wrong too!)&lt;/p&gt;&#xA;" OwnerUserId="6181" LastActivityDate="2016-10-13T11:43:09.960" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8883" PostTypeId="2" ParentId="8871" CreationDate="2016-10-13T11:49:04.983" Score="3" Body="&lt;p&gt;Perhaps an easier question would be - what percentage of the earth has discovered oil/gas fields! This data should be easier to find than the surveys themselves, and can probably give you a rough estimate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For an idea of the publically available seismic surveys conducted around western Australia, this site (&lt;a href=&quot;https://wapims.dmp.wa.gov.au/wapims&quot; rel=&quot;nofollow&quot;&gt;https://wapims.dmp.wa.gov.au/wapims&lt;/a&gt;) can show you all of their stored survey data. Not sure where you could get other data though, sorry!&lt;/p&gt;&#xA;" OwnerUserId="6181" LastActivityDate="2016-10-13T11:49:04.983" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8884" PostTypeId="2" ParentId="8838" CreationDate="2016-10-13T11:53:24.747" Score="2" Body="&lt;p&gt;Maybe it's outside the scope of your question (I.e. droughts) but the lack of rainfall associated with warming climates does (and is) affecting saline water intrusion along coastal aquifers, which inevitably affects our fresh water access...!&lt;/p&gt;&#xA;" OwnerUserId="6181" LastActivityDate="2016-10-13T11:53:24.747" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8885" PostTypeId="2" ParentId="8878" CreationDate="2016-10-13T16:00:44.677" Score="5" Body="&lt;p&gt;This is just supplemental information to &lt;a href=&quot;https://earthscience.stackexchange.com/a/8880/6031&quot;&gt;the accepted answer&lt;/a&gt; by @gerrit &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I took the ESA cloud cover fraction map provided there, and added dots that represent the approximate locations of the ground stations shown in the 2014 map shown in the question, just to get a rough idea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I used the &lt;em&gt;extremely cool&lt;/em&gt; &lt;a href=&quot;http://www.submarinecablemap.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Submarine Cable Map site&lt;/a&gt; to identify the likely fiber optic 'hub locations' that are likely to correspond to the ground station location. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So indeed, a large number (but not all) of these sites appear to coincide with low cloud coverage fraction areas of the earth, as well as submarine optical fiber &quot;landing sites.&quot; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Mxr7n.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Mxr7n.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-10-17T12:42:20.757" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8886" PostTypeId="1" AcceptedAnswerId="8888" CreationDate="2016-10-13T16:44:30.430" Score="-3" ViewCount="796" Body="&lt;p&gt;I though that geologists and geographers are specialists in one of the branches of Earth science, but they aren't.&#xA;Geology is a branch of Earth science, but geologists and geographers are in this category:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A geologist is a scientist who studies the solid and liquid matter that constitutes the Earth as well as the processes and history that have shaped it. Geologists usually engage in studying geology&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;A geographer is a scholar whose area of study is geography, the study of Earth's natural environment and human society. Although geographers are historically known as people who make maps, map making is actually the field of study of cartography, a subset of geography&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Why aren't geologists and geographers specialists in Earth science if they are in the geology category?&lt;/p&gt;&#xA;" OwnerUserId="6784" LastEditorUserId="2536" LastEditDate="2016-10-13T23:54:51.930" LastActivityDate="2016-10-14T23:26:27.710" Title="Why are geologists and geographers not specialists in one of the branches of Earth science?" Tags="|geology|terminology|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8887" PostTypeId="2" ParentId="8886" CreationDate="2016-10-13T19:05:32.737" Score="1" Body="&lt;p&gt;Perhaps you are being misled by a rather narrow set of definitions. Many geologists are indeed specialists in a geological or related field. It is said that modern professional people have to learn one major new skill every 5 years or so, and one minor skill every year. That is certainly true in my experience. Talk to geologists and you will find that a large proportion have specialist skills such as hydrogeology, hydrology, climate change, climatology, oceanography, geomorphology, petrology, sedimentology, volcanology, and a host of other specialities.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-10-13T19:05:32.737" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8888" PostTypeId="2" ParentId="8886" CreationDate="2016-10-13T23:44:57.227" Score="4" Body="&lt;p&gt;Geographers may or may not be Earth Scientists. It is a broad field and includes human geography, cultural geography, economic geography, transportation geography, and other sub-disciplines that are not studies of the physical nature of the earth. &lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2016-10-13T23:44:57.227" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8889" PostTypeId="2" ParentId="8879" CreationDate="2016-10-14T00:59:15.520" Score="1" Body="&lt;p&gt;Too long for a comment, so I'll post here, but it's far from a complete answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basalt can't become continental crust because the elements are different.  Iceland is made up of primarily basalt rock.  (&lt;a href=&quot;http://www.geoguiding.asia/Geology-Iceland/816&quot; rel=&quot;nofollow&quot;&gt;80% per this article&lt;/a&gt;).  So it's made up of a different material than continental crusts.   Basalt rock is also less sturdy and less enduring than granite, so it's unlikely that a continental crust could be formed out of Icelandic eruptions or any similar eruptions.   My best guess is that Iceland will break apart over time, preventing the formation of a permanent land-mass.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Granite, the primary material in continental crust, has more Aluminum and Potassium in it.    Basalt, the heavier stuff, has more Magnesium.  &lt;a href=&quot;http://jersey.uoregon.edu/~mstrick/AskGeoMan/geoQuerry27.html&quot; rel=&quot;nofollow&quot;&gt;Source&lt;/a&gt;.    They are made from distinctly separate processes and material, so one can't simply be turned into the other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While I have no doubt that some mixing goes on within the earth's mantle, I don't believe a significant amount of new continental crust is regularly being formed because to form new crust, you would need free aluminum ready to bind with Oxygen and Silicates and I believe most of the aluminum has already done that.    That's my layman's answer anyway.  I'm open to being corrected.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="543" LastEditDate="2016-10-14T06:01:58.360" LastActivityDate="2016-10-14T06:01:58.360" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8890" PostTypeId="1" AcceptedAnswerId="8898" CreationDate="2016-10-14T07:02:48.913" Score="2" ViewCount="147" Body="&lt;p&gt;This is about a group project for our science class and we've decided to do a physical model on clouds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We could use liquid nitrogen and hot water to demonstrate the formation of the clouds and we are aware that it doesn't form like that in the nature. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I just wanted to ask, what's the pressure required for clouds to form? I found out that it's -10&lt;sup&gt;o&lt;/sup&gt; C temp. but nothing about pressure (lower than normal but don't have the exact number)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any ideas? :( I'm starting to feel pretty desperate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can we use the nitrogen to decrease the temperature to -10 and then pressure, and wait for liquid water to condensate? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any kind of answer will be appreciated. Thanks :) &lt;/p&gt;&#xA;" OwnerUserId="6787" LastEditorUserId="1411" LastEditDate="2016-10-15T04:08:38.480" LastActivityDate="2016-10-31T04:44:37.327" Title="Making clouds for science project" Tags="|clouds|homework|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8891" PostTypeId="1" CreationDate="2016-10-14T13:38:08.350" Score="1" ViewCount="200" Body="&lt;p&gt;Studying for a midterm and I came across the following question. Is aspect more or less important than material type in determining permafrost thickness?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In physical geology, aspect is the compass direction that a slope faces. So the trail of the sun from east to west in the Northern hemisphere would provide more sunlight to the South than the North, but I would think that material type for determing permafrost would be more important. Not sure how but looking for a explanation&lt;/p&gt;&#xA;" OwnerUserId="6789" LastEditorUserId="6789" LastEditDate="2016-10-14T14:08:19.980" LastActivityDate="2016-10-14T15:57:44.753" Title="Permafrost thickness" Tags="|geology|geography|permafrost|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8892" PostTypeId="2" ParentId="8891" CreationDate="2016-10-14T15:57:44.753" Score="1" Body="&lt;p&gt;This is a non-exhaustive list of factors influencing the permafrost thickness :&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;latitude&lt;/li&gt;&#xA;&lt;li&gt;altitude&lt;/li&gt;&#xA;&lt;li&gt;aspect&lt;/li&gt;&#xA;&lt;li&gt;material type&lt;/li&gt;&#xA;&lt;li&gt;nature of the regional climate (dry, oceans, continental)&lt;/li&gt;&#xA;&lt;li&gt;geologic history of the permafrost (formed after the last glacial maximum, or before?)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Time is important: older permafrost can be very deep, especially in areas such as in Siberia, Yukon/Alaska where the effect of glacier was limited, thus exposing the ground to cold conditions for long time. Some areas in the Canadian archipelago are in excess of 1 km deep, and more than 500 m is not uncommon, largely depending on local and time conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yet, huge discrepancies in permafrost depth can be found between western Canada/AK, eastern Canada, Northern Europe and Siberia, given a constant latitude, and therefore isolation and thus comparable aspect. As an example at Svalbard (78N), permafrost depth was reported to be less than &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/ppp.380/abstract&quot; rel=&quot;nofollow&quot;&gt;400 m&lt;/a&gt;, while regional depth in the central canadian archipelago north of Baffin Island is more than 500 m (for 73 - 75 N) and 1500 m in northern Siberia (which is at a lower latitude than Svalbard).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get back to your question, aspect (or solar radiation input) is pretty much uniform for a given latitude - but in this case, for the same latitude, permafrost depth vary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, material type vary locally. If wetlands, mosses and vegetation will contribute to cool the ground, enabling deeper permafrost in those areas. Areas were there is a lot of snow (snowbanks) will have a warmer permafrost compared to crests nearby. Lakes change how heat can be extracted from the ground (latent heat effect) so permafrost will be thin under a lake compared to around the lake (lake being a type of material in the context of your question). Desert ? Rock outcrop ? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Each type of environment behave in a certain way regarding heat extraction and ultimately heat exchanges, which have a lot to do with the nature of the surface.&lt;/strong&gt;.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2016-10-14T15:57:44.753" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8893" PostTypeId="1" CreationDate="2016-10-14T16:47:20.493" Score="1" ViewCount="305" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KZ5A7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KZ5A7.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I worked on the map and found out that point A is 60&lt;sup&gt;o&lt;/sup&gt;N 120&lt;sup&gt;o&lt;/sup&gt;W by looking at it, but the answer said that it A is suppose to be 30&lt;sup&gt;o&lt;/sup&gt;N 90&lt;sup&gt;o&lt;/sup&gt;W. For B, I got 30&lt;sup&gt;o&lt;/sup&gt;S 60&lt;sup&gt;o&lt;/sup&gt;W, but the answer said that B is 23&lt;sup&gt;o&lt;/sup&gt;S 43&lt;sup&gt;o&lt;/sup&gt;W. But points 23 and 43 are &lt;strong&gt;not&lt;/strong&gt; on the map! What went wrong?&lt;/p&gt;&#xA;" OwnerUserId="6784" LastActivityDate="2016-10-14T16:47:20.493" Title="How to find latitude and longitude?" Tags="|measurements|" AnswerCount="0" CommentCount="4" ClosedDate="2016-10-18T14:19:46.353" ContentLicense="CC BY-SA 3.0" />
  <row Id="8896" PostTypeId="2" ParentId="8838" CreationDate="2016-10-14T20:59:12.347" Score="3" Body="&lt;p&gt;To answer the question &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Are there any known or suspected historical i.e. Holocene climatic warming associated with negative impacts on human populations?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;One recent (actual) example that come to mind is the sea level rising. &lt;a href=&quot;http://climate.nasa.gov/vital-signs/sea-level/&quot; rel=&quot;nofollow&quot;&gt;Here&lt;/a&gt; we see that since the early satellite measurements in 1993, sea level rise was about 8 cm. On the same page, less reliable gauges indicated a coastal sea level rise of 20 cm between 1870 and the late 1990.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some Islands are particularly vulnerable to sea level changes, in regard with fresh water supplies, soils and shore degradation following storms and strong high tides, etc. Marshall Island (~2 m), Maldives (~1 m) are examples of emplacements with very low mean ground level. It is really a question of time before these places become unlivable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While these are small islands, other populous places are quite vulnerable to similar situations such as &lt;a href=&quot;http://www.grida.no/publications/vg/climate/page/3086.aspx&quot; rel=&quot;nofollow&quot;&gt;Bangladesh&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2016-10-14T20:59:12.347" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8897" PostTypeId="2" ParentId="7328" CreationDate="2016-10-14T21:40:14.680" Score="1" Body="&lt;p&gt;How about using the same 2D wind rose plot for an additional figure, but color it with respect to velocity in the vertical? So you will have two of the similar looking wind rose plots, they will both show the directions in the horizontal 2D, but the second plot will have a colorbar that ranges ,say, from -1 m/s to 1m/s. I think that would be a very useful plot. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You will need to store the indices used in the calculation of the horizontal directions and calculate the histogram for the vertical flow that corresponds to them. Or just keep the part of the code where horizontal directions are calculated but use the vertical velocity to calculate the magnitude. Keep the sign to indicate upward/downward.&lt;/p&gt;&#xA;" OwnerUserId="120" LastActivityDate="2016-10-14T21:40:14.680" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8898" PostTypeId="2" ParentId="8890" CreationDate="2016-10-14T22:18:07.667" Score="8" Body="&lt;p&gt;To form a cloud, generally speaking, pressure does not play a significant factor (with the exception of the effect on temperature).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to prove that to yourself, go outside when it is foggy and measure the air pressure. Fog is a cloud, and pressure likely hasn't changed as much as it does in the vertical direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far a forming a cloud, it is actually relatively easy. You only need to decrease the temperature to it's dewpoint. You may want relatively dirty air, so that the solute effect makes it easy to form drops. Silver iodide would be good for this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For reference, the &lt;a href=&quot;http://www.inscc.utah.edu/~tgarrett/5200/Notes/Kohler.pdf&quot;&gt;Kohler curve&lt;/a&gt; describes the saturation needed for cloud droplets to form.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2016-10-14T22:18:07.667" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8899" PostTypeId="2" ParentId="8819" CreationDate="2016-10-14T22:45:37.813" Score="0" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;In physical oceanography and fluid dynamics, the wind stress is the shear stress exerted by the wind on the surface of large bodies of water – such as oceans, seas, estuaries and lakes. It is the force component parallel to the surface, per unit area, as applied by the wind on the water surface.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;For more information go to: &lt;a href=&quot;https://en.wikipedia.org/wiki/Wind_stress&quot; rel=&quot;nofollow&quot;&gt;https://en.wikipedia.org/wiki/Wind_stress&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6784" LastActivityDate="2016-10-14T22:45:37.813" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8900" PostTypeId="2" ParentId="8886" CreationDate="2016-10-14T23:26:27.710" Score="2" Body="&lt;p&gt;Actually, Geographers do study human that affect on the local area on Earth. So, Geography is just a general and there are branches that they work with Geology, Climatology, Weather, Soils, and so on etc. So for an example, a Geographer would have to write down a description about that specific area. Like for example, why would the Syrians migrate to Europe ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is an example of Geography branches : &lt;a href=&quot;http://image.slidesharecdn.com/1-introductiontoworldgeography-150819014233-lva1-app6892/95/1-introduction-to-world-geography-11-638.jpg?cb=1439948742&quot; rel=&quot;nofollow&quot;&gt;http://image.slidesharecdn.com/1-introductiontoworldgeography-150819014233-lva1-app6892/95/1-introduction-to-world-geography-11-638.jpg?cb=1439948742&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geologist is a person who does study under the Earth from the surface all the way to the mantle. I am sure there are branches for Geology as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A lot of people believe Geography is a science and it is not a science but it is a Humanities and Social Science. There are some universities that put Geography and Geology together, while some of them put Geography in Natural Resources and it depends on where you go to college. So,it depends on the person who has their own opinion about Geography and Geology.&lt;/p&gt;&#xA;" OwnerUserId="5771" LastActivityDate="2016-10-14T23:26:27.710" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8903" PostTypeId="2" ParentId="8838" CreationDate="2016-10-16T02:07:51.570" Score="3" Body="&lt;p&gt;Your question covers a lot of ground and maybe should be broken up into parts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Written human history is only a few thousand years old.   Over most of that period there's been a gradual cooling.   &lt;a href=&quot;http://xkcd.com/1732/&quot; rel=&quot;nofollow&quot;&gt;Source&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You also have to say where.  European farming is probably more susceptible to cold spells.   Middle Eastern farming to drought and hot spells.  USA farming, some of both.  Certainly the NorthEastern settlers were badly affected during the year without summer, but had there been Midwestern or California farm during 1816, they (Might) have come out OK.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While it's not brought up very often, one of the possible causes of the Syrian conflict over the last 5-6 years is drought and food shortages possibly brought on by climate change.   &lt;a href=&quot;http://www.nytimes.com/2015/03/03/science/earth/study-links-syria-conflict-to-drought-caused-by-climate-change.html&quot; rel=&quot;nofollow&quot;&gt;Article here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's geological records of extinction being tied to climate change, but warming and cooling.  Article (&lt;a href=&quot;https://www.scientificamerican.com/article/mass-extinctions-tied-to-past-climate-changes/&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;) and &lt;a href=&quot;http://news.nationalgeographic.com/news/2014/03/140331-global-warming-climate-change-ipcc-animals-science-environment/&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another problem, if you go back a few thousand years is that it's not just warming and cooling but Milankovich cycles are a factor.   Milankovich cycles (not the rise and fall of ice ages) are thought to drive the Greening and droughting of the Sahara.  Article &lt;a href=&quot;https://en.wikipedia.org/wiki/North_African_climate_cycles&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Egypt was lush and fertile until about 4,200 years ago when it was hit  by a killer drought.   The Sahara desert was lush and fertile as recently as 6,000 years ago.   The Egyptian downfall (and the downfall of civilizations in parts of India and Pakistan) about 4,000 years ago is associated to local climate change.   Articles &lt;a href=&quot;http://www.dailymail.co.uk/sciencetech/article-2189802/Egyptian-kingdom-died-4-200-years-ago-following-mega-drought-caused-climate-change.html&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;http://www.foxnews.com/tech/2012/05/29/4000-years-ago-climate-change-caused-massive-civilization-collapse.html&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;.  There was a gradual global cooling during that period around 4,200 years ago, so that might be worth looking into.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To research this properly I'd look at multiple parts of the Earth.  Your evidence seems much too European focused and I'd not look at just warming and cooling but localized Milankovich driven effects such as the African monsoon mentioned in the article on the Sahara, above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You wrote this, but this is inaccurate:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the &quot;The Big Sog&quot; outcome predicted by some climate models in which&#xA;  the increase in world temperatures leads to significantly higher&#xA;  humidity world wide which causes incessant rain.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Warmer weather doesn't lead to greater humidity.  Humidity is percentage of saturation.  Warmer air holds more water, so it has a higher saturation limit.   The humidity as the percentage of peak saturation, doesn't necessarily increase with warmer air, in fact, warmer temperature likely drops humidity levels on average, while increasing atmospheric water vapor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What this means, generally speaking, is that it takes more water to be evaporated for for the air to get saturated, so it rains less often, on average, but it also rains harder when it does rain.  Now, that's grossly oversimplified because rainfall has to do with rising and falling moist air and rapid cooling to create condensation, but I've read no theories that say that man made climate change will make it rain more often.  In fact, I've read the opposite.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Snowfall is the source of many rivers flow rates.  Less snow means less river flow and global warming often means less snow.    Plant transpiration also drops as CO2 levels rise, so the effect is that you have plants and rivers putting less water back into the atmosphere as a result of climate change.  This leads to drier air where the land relies on recycled water.  Land that relies on oceanic evaporation should be fine and perhaps wetter on average due to climate change.   Land that relies on snow runoff and transpiration from plants returning water to the air should get drier and in combination with warmer air being able to hold more water and less water returning to that air, there should be regions of significant decrease in rainfall and increase in droughts due to climate change.   A curious effect of man made climate change is that it might somewhat green the Sahara, but it will likely create other deserts, especially in regions that rely on recycled rain water, not water evaporated off the ocean.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you say this:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Drought conditions can cause higher peak daytime temperatures because&#xA;  of the loss of cloud cover, but these peaks are offset by nighttime&#xA;  lows by the same mechanism, just as occurs in deserts. The actual heat&#xA;  content of the atmosphere, its enthalpy, which drives weather and&#xA;  climate, actually decreases because most of the heat is held in the&#xA;  atmospheric humidity and the biomass.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That may be accurate about deserts and total heat around the desert, but deserts are a small part of Earth's surface.  70% of the earth is covered by oceans, so the primary driver to how much water vapor is in the atmosphere of the earth is surface temperature above the oceans.   As the Earth warms, there should be more water vapor on average (growing deserts probably won't be enough to undo that), and because water-vapor is a greenhouse gas, that should play a role in trapping more heat.   Total amount of water vapor in the atmosphere is a feedback mechanism, that should lead to an increase in warming overall, not cooling.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not sure you'll like my answer, as I disagree with a few of your points, so, feel free to take it with a grain of salt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Corrections welcome.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2016-10-16T02:07:51.570" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8904" PostTypeId="1" AcceptedAnswerId="8908" CreationDate="2016-10-16T04:46:37.480" Score="7" ViewCount="3150" Body="&lt;p&gt;The Washington Post article &lt;a href=&quot;https://www.washingtonpost.com/news/speaking-of-science/wp/2016/10/12/scientists-discover-hundreds-of-footprints-left-at-the-dawn-of-modern-humanity/&quot; rel=&quot;noreferrer&quot;&gt;Scientists discover hundreds of footprints left at the dawn of modern humanity&lt;/a&gt; describes the geological dating of  stratified layers of mud by analyzing and dating minerals within each layer.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;But since floods jumble materials of different origins and ages together, that meant the scientists had to date dozens of different minerals. The youngest crystal in the footprint layer would represent the oldest possible age for the prints; the oldest crystal in the layer above it would represent the youngest they could be.&lt;/p&gt;&#xA;&lt;p&gt;Using the argon-argon dating technique, by which scientists measure the decay of an isotope called Argon-40 into Argon-39 in order to find the age of crystals, they came up with a rough approximation of the footprints' age: 19,000 years at the oldest, 10,000 or 12,000 years at the youngest.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I can't exactly follow the logic, but I'm asking here about the dating process itself. How does argon-argon dating work?&lt;/p&gt;&#xA;&lt;p&gt;I do not think that &lt;a href=&quot;https://en.wikipedia.org/wiki/Isotopes_of_argon#Argon-40&quot; rel=&quot;noreferrer&quot;&gt;Argon-40&lt;/a&gt; decays into Argon-39 as the article states, at least not all by itself. And when I look at the &lt;a href=&quot;https://en.wikipedia.org/wiki/Argon%E2%80%93argon_dating&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia article&lt;/a&gt;, the discussion is so technical and defensive that I can't actually picture what is going on.&lt;/p&gt;&#xA;&lt;p&gt;How does argon-argon dating work?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-06-16T09:22:05.560" Title="How does argon-argon dating work - need a simple but not-wrong explanation" Tags="|dating|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8905" PostTypeId="2" ParentId="8870" CreationDate="2016-10-16T17:06:44.000" Score="0" Body="&lt;p&gt;You are at the same voltage potential as the earth most of the time, so you don't get zapped. Electrical current only exists where there are voltage differences, and a path for the electricity to flow through.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Imagine a big pond full of water. The water just sits there, right? Now imagine you dig a ditch to an adjacent dry pond. Now there is a difference in potential energy (thanks, gravity), and there is a path through which the energy can travel to seek a steady state again. Once enough water flows from the full pond to the dry pond, the energy potential (now think of this as voltage) will be equal and water will stop flowing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Electricity is not so different in this sense. Electromagnetism is what holds the very atoms of your body together. It's pervasive and there are voltages on everything all the time.  What you think of as electricity is electrical &lt;em&gt;current&lt;/em&gt;, which is the phenomenon of electrical charge moving from one place to another.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If two items both had a 1,000,000 Volt electrical charge on them and they touched... nothing would happen. There's no voltage potential between them. Bit if one had a 1,000,000 Volt charge and one had a 1,000,120 Volt charge, and you ran a wire between them, you would read 120 Volts on that wire at least momentarily, and that reading would decrease until it reached 0, when the two objects reached the same charge.&lt;/p&gt;&#xA;" OwnerUserId="6796" LastActivityDate="2016-10-16T17:06:44.000" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8906" PostTypeId="2" ParentId="4452" CreationDate="2016-10-16T19:17:12.520" Score="2" Body="&lt;p&gt;Simple harmonic (SH) long crested cloud waves, commonly seen in windswept skies, occur between adjacent air strata flowing in different directions. One stratum is warmer, with higher humidity, causing cloud formation along the inter-stratum boundary. The simple harmonic wave formations conform to the same physics as the Reynolds U-tube experiment taught in fundamental fluid dynamics, where tube tilting to a critical level, causes SH waves to form along the compliant water/carbon bi-sulfide boundary. In the cloud waves and in the U-tube waves we see compliant boundary manifestations of the boundary layer oscillations of transition that Schubauer and Skramstad demonstrated in wind tunnel air flow along a flat plate in 1941.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similar (invisible) shear waves develop when the sky is clear – when there is no condensation and cloud formation. These are recognized by pilots who, while flying through this variety of clear air turbulence (CAT), get a SH shuddering feeling “as if flying over a washboard”.  These SH inter-stratum waves are occasionally revealed by SH waves developing in the lingering contrails of jet aircraft (Simple Harmonics, Aylmer Express, 2015, figures 16, 17, p. 14).&lt;/p&gt;&#xA;" OwnerUserId="6798" LastActivityDate="2016-10-16T19:17:12.520" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8908" PostTypeId="2" ParentId="8904" CreationDate="2016-10-16T23:21:14.730" Score="8" Body="&lt;p&gt;As noted in the comments the wikipedia articles (at the time this question was submitted) are contradictory. There are quite a few steps to the logic of how argon-argon dating works but none are too complicated, although I won't go into all of the possible interferences. One thing to keep in mind is that high-precision isotope measurements always measure ratios between isotopes, not absolute concentrations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To understand argon-argon dating, you need to understand potassium-argon dating.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The isotope potassium-39 makes up about 93% of natural potassium. Potassium-40 is radioactive but has such a long half-life that it is primordial - it has been around since the earth was being formed. Because of this, we can assume that the potassium-40:potassium-39 ratio in minerals at any time is a constant. Potassium-40 decays in 2 different ways. Most decays by beta decay to calcium-40. About 10.7% decays to Argon-40 by emitting a positron. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the argon-40 stays trapped in the crystal and you can measure the ratio of potassium-40 to argon-40, then you know how long it has been since the mineral formed. This also assumes that there is no other source of argon like trapped air. A problem is that it takes two separate measurements to get the potassium concentration and the argon isotope ratios, increasing the uncertainty. Argon-argon dating gets around many of the issues by measuring only multiple isotopes of argon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The trick is to irradiate the sample with neutrons along with samples of known age. Some of the potassium-39 forms argon-39 by an n,p reaction. By converting potassium-39 to argon-39 then measuring the argon-39:argon-40 ratio, you can calculate the sample's potassium-40:argon-40 ratio, remembering potassium-40:potassium-39 is fixed. The standards of known age are used to account for differences in the neutron flux during irradiation. Argon-36 in the sample accounts for any air contamination.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Argon-argon dating, ideally assumes that:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;all argon-40 in the sample comes from either atmospheric argon or from decay of potassium-40 in the sample&lt;/li&gt;&#xA;&lt;li&gt;all argon-39 in the sample comes from irradiation of potassium-39 in the sample and as noted above, if you know potassium-39:argon-40 ratio then you know the potassium-40:argon-40 ratio because the potassium-40:potassium-39 is constant (at this point in time)&lt;/li&gt;&#xA;&lt;li&gt;all argon-36 is the sample is from atmospheric argon&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The actual calculations are pretty simple algebra, combining all the pieces.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastEditorUserId="1242" LastEditDate="2016-10-17T21:19:31.103" LastActivityDate="2016-10-17T21:19:31.103" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8909" PostTypeId="2" ParentId="7328" CreationDate="2016-10-17T02:26:18.350" Score="6" Body="&lt;p&gt;The context I often see the u,v,w components shown in one plot are forward and backward trajectory plots like those from the &lt;a href=&quot;http://www.intechopen.com/source/html/41274/media/image17.jpeg&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA HYSPLIT Model&lt;/a&gt;, which provides separate panels for horizontal and vertical movement.  There is also 3-D imagery like what's available from UCAR in the &lt;a href=&quot;http://www.unidata.ucar.edu/software/idv/docs/workshop/datadisplays/wrf/InteractiveWRFGridDisplays.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;cross sections&lt;/a&gt; examples for WRF, shown below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kK21x.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kK21x.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2016-10-18T01:38:06.890" LastActivityDate="2016-10-18T01:38:06.890" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8910" PostTypeId="1" CreationDate="2016-10-17T06:07:44.610" Score="7" ViewCount="1904" Body="&lt;p&gt;Himalayas are currently rising about 5 mm/year. What will be the highest point they can reach?&lt;/p&gt;&#xA;" OwnerUserId="2819" LastActivityDate="2016-10-17T22:16:38.507" Title="Himalayas are currently rising. What will be the highest point they can reach?" Tags="|geology|plate-tectonics|mountains|tectonics|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8911" PostTypeId="2" ParentId="8910" CreationDate="2016-10-17T08:37:21.627" Score="10" Body="&lt;p&gt;The Himalayas are indeed rising, but they are also being eroded at a comparable rate. It will come as no surprise to anyone that the maximum possible height of a mountain on Earth is only marginally higher than Mt Everest, that is probably about 9000 to 10,000 metres high. There are, of course compressive / convergent plate boundaries where there is a &lt;em&gt;potential&lt;/em&gt;  tendencey to build higher mountains, but non-linear counter processes kick in to counteract the mountain building. There are three processes, glacial erosion, shear collapse and lower crust / upper mantle plasticity. The latter is the most important. As lateral compression builds higher mountains, the mountain roots are depressed into the hot plastic region such that the mountain literally sinks under its own weight, deforming the root zone, sometimes in spectacular fashion. Go to Scotland, or Norway, where you can see the eroded remains of the long-gone Caledonides, and you can see the exposed and metamorphosed root zone of mountains that were once as big as the Himalayas. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In principle, the mountain would eventually collapse by shear failure, simply because the rock isn't strong enough to support the weight of gigantic mountains. In practice, deformation takes place before the shear failure is reached.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then there are glaciers. The higher the mountain gets, the more rain  turns to snow, then to ice, which is a phenomenally effective erosive agent (just look at any of the worlds recently glaciated terrains - European Alps, Patagonian Alps, Norway, Alaska, New Zealand, etc., to see the spectacular erosion). This erosion peaks at a high altitude, but not at the very highest altitude, where the atmosphere is so cold that it cannot deliver much moisture - so very little snow. Result: glacial erosion takes bites out of the mountain at middle-upper elevations, thereby keeping the slopes steep, whence gravity collapse along pressure release joints, and other related processes. Hence occasional peaks get close to 9000 metres but, in geological terms, they don't last long before erosion brings them down. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2016-10-17T22:16:38.507" LastActivityDate="2016-10-17T22:16:38.507" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="8912" PostTypeId="2" ParentId="2843" CreationDate="2016-10-17T08:50:04.983" Score="0" Body="&lt;p&gt;The whole plate tectonic system is good for a few billion years yet. David is correct that water, as a lubricant, is needed to keep the system moving, but a 10% warming of the sun isn't enough to completely destroy the oceans. That will occur, but not until the sun moves close to, or into its red giant phase several billion years from now. The other factor is uncertainty as to how long there will be sufficient radioactive heat to overcome viscous drag of the convective cells which underlie the crustal plates. There has been much speculation, but I am not aware of any convincing analysis of how long this will take.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-10-17T08:50:04.983" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8913" PostTypeId="1" AcceptedAnswerId="8934" CreationDate="2016-10-18T11:26:11.283" Score="5" ViewCount="780" Body="&lt;p&gt;This (&lt;a href=&quot;http://www.skepticalscience.com/dodgy_diagrams_1_residence_time.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;rather dodgy&lt;/a&gt;) graph shows a number of estimates of the residence time of atmospheric CO&lt;sub&gt;2&lt;/sub&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fQi4j.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fQi4j.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question concerns why there is so much variation (Machta, 1974 about 3 years, Seuss and Druffe, 1983 about 12 years) in the estimates based on the decay of bomb &lt;sup&gt;14&lt;/sup&gt;C, given that it seems reasonably easy to estimate from the decay after the nuclear test ban treaty in 1963:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GB7DS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GB7DS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there some complicating factor?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've been doing some thinking and research about this and some issues that might be relevant are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;small &lt;sup&gt;14&lt;/sup&gt;C generated from nuclear power reactors ,&lt;/li&gt;&#xA;&lt;li&gt;the carbon cycle is not at equilibrium, but a naive analysis might&lt;br&gt;&#xA;assume that.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="624" LastEditorUserId="725" LastEditDate="2017-05-12T14:38:58.023" LastActivityDate="2017-05-12T14:38:58.023" Title="Estimating the residence time of atmospheric CO2 from bomb 14C" Tags="|atmosphere|carbon-cycle|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8914" PostTypeId="1" CreationDate="2016-10-18T11:42:30.413" Score="1" ViewCount="313" Body="&lt;p&gt;My understanding is that because a rock is composed of variety of minerals, so it does not have fix melting point, rather there is a range below which whole rock is solid and above which whole rock is liquid. I want to know this liquidus and solidus temperature for granite rock based on pressure (as we can't ignore role of pressure inside earth where granite is formed?&lt;/p&gt;&#xA;" OwnerUserId="5557" LastActivityDate="2016-10-18T18:49:02.567" Title="What is solidus and liquidus temperature of granite?" Tags="|volcanology|mineralogy|petrology|magmatism|igneous|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8917" PostTypeId="1" CreationDate="2016-10-19T01:59:48.610" Score="4" ViewCount="2353" Body="&lt;p&gt;Recently, there has been a lot of information about &quot;King Tides&quot; (i.e, &lt;a href=&quot;http://oceanservice.noaa.gov/education/kits/tides/tides06_variations.html&quot; rel=&quot;noreferrer&quot;&gt;perigean spring tides&lt;/a&gt;) on the news with a &lt;a href=&quot;http://nckingtides.web.unc.edu/&quot; rel=&quot;noreferrer&quot;&gt;number of groups&lt;/a&gt; relating the peak king tide to future normal conditions (2050) under sea level rise scenarios along the east coast of the United States. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The effects on the magnitude of the tides are obvious when we compare normal tides (&lt;a href=&quot;http://dx.doi.org/10.1175/1520-0426(2002)019%3C0183:EIMOBO%3E2.0.CO;2&quot; rel=&quot;noreferrer&quot;&gt;OSU model&lt;/a&gt; results for a day in 2010) &lt;a href=&quot;https://i.stack.imgur.com/N3FBf.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/N3FBf.gif&quot; alt=&quot;http://earthscience.stackexchange.com/questions/8508/the-motion-of-tides&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;with the &lt;a href=&quot;http://volkov.oce.orst.edu/tides/&quot; rel=&quot;noreferrer&quot;&gt;recent tides&lt;/a&gt; for the entire planet (spring tides):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/E3mUO.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/E3mUO.gif&quot; alt=&quot;October 19, 2016&quot;&gt;&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;While most of the difference is associated with the spring tides, about &lt;a href=&quot;http://oceanservice.noaa.gov/facts/perigean-spring-tide.html&quot; rel=&quot;noreferrer&quot;&gt;2-3%&lt;/a&gt; is associated with the relative position of the Moon. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is related to the recurrence interval of perigean spring times. Some &lt;a href=&quot;https://en.wikipedia.org/wiki/Perigean_spring_tide&quot; rel=&quot;noreferrer&quot;&gt;sources&lt;/a&gt; mention that they occur 3-4 times a year. If that is the case, then why such a focus on the mid-October 2016 event? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another related question, which constituent of the tide is associated with the perigean/apogean oscillations?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2016-10-19T02:13:28.113" LastActivityDate="2018-05-03T10:33:17.367" Title="How often do king tides (perigean spring tides) occur?" Tags="|ocean|oceanography|tides|moon|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8919" PostTypeId="2" ParentId="8790" CreationDate="2016-10-19T03:49:45.590" Score="2" Body="&lt;p&gt;If you're asking about how they are able to distinguish different layers of information on the Earth, your answer is found in the field of Remote Sensing. Using sensors running on several satellite systems (e.g. MODIS, ETM) that are isolated to pick up specific radiative bands (IR, NIR, Visible, etc.) you can derive some pretty amazing information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using map algebra on these bands, you can figure things out like cloud cover, vegetation health, elevation, temperature and land cover of the surface, etc. Many of these data sets can be found directly through NASA or USGS. Creating masks of different information using these techniques can lead to really amazing visualizations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The really fascinating thing is that a lot of this information can be calculated on the fly using raw data and any GIS infrastructure or scripts. That's likely how NASA is able to visualize these data products the moment they collect them.&lt;/p&gt;&#xA;" OwnerUserId="5536" LastActivityDate="2016-10-19T03:49:45.590" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8923" PostTypeId="1" AcceptedAnswerId="8925" CreationDate="2016-10-20T02:55:59.100" Score="3" ViewCount="598" Body="&lt;p&gt;I've been trying to collate the reasons why Tornado Alley in North America is what it is. So far, I have the following:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The continental landmass is in the mid-latitudes (where the polar jet has the greatest amount of influence).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;There are no geographic barriers, like bodies of water or mountains, between the North Pole and the rest of the NA landmass. Australia, New Zealand, South Africa (and Argentina for the most part) are separated from the South Pole/Antarctica by water.&lt;br /&gt;There's not much in the way of cold polar air dipping down as far south as the Florida Panhandle if there's a deep enough trough in the polar jet.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Sources of abundant heat and moisture at the surface. This primarily comes from the Gulf of Mexico, but there's also the Caribbean Sea, tropical Atlantic, plus the influence of the Gulf Stream and Bermuda High.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Large areas devoid of rough/rugged terrain. Besides the Appalachians and the Ozarks, there isn't a lot of mountainous terrain in the middle and eastern sections of the continent. The clash between tropical and polar air can continue undisrupted. In fact, the Appalachians can have the same funneling effect to tropical air that the Rockies have, shielding the Mid-Atlantic/Delmarva region while the Mid-South (sometimes even up to the Ohio River Valley) gets raked by tornadoes.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Mountains and high desert to the west. Warm, dry air coming off the High Plains in the leeward side of the Rockies and the High Plains in eastern New Mexico create westerlies at mid-levels. It acts as a lid, preventing surface moisture from rising. This is called a capping inversion, &quot;cap&quot; or elevated mixed layer. When the cap erodes, supercells can erupt.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Wind shear: Cold, dry northwest winds aloft; warm, dry westerlies at mid levels; and warm, moist air at the surface. Not only is wind direction changing with height, but wind speed as well (if there's a strong flow of moisture from the southeast, a &quot;low level jet&quot;, then shear is further exacerbated).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;But I wonder, what if North America were in the southern hemisphere? Would the mountains and high desert have to be situated on the eastern side of the continent to compensate? The predominant airflow in the northern hemisphere is west to east, due to Coriolis forces caused by the Earth's spin.&lt;/p&gt;&#xA;" OwnerUserId="6816" LastEditorUserId="595" LastEditDate="2016-10-20T08:25:31.170" LastActivityDate="2016-10-21T22:38:57.473" Title="If North America were in the southern hemisphere, would the mountains and high desert have to be -east- of Tornado Alley?" Tags="|meteorology|tornado|coriolis|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8924" PostTypeId="2" ParentId="8923" CreationDate="2016-10-20T05:10:07.347" Score="0" Body="&lt;p&gt;It isn't exactly clear what you are suggesting. Do you mean sliding N America south, with its current orientation, or flipping it over on an equatorial reflection axis, or flipping it around the &lt;em&gt;climatic&lt;/em&gt; equatorial axis (about 5 degree south due to the unequal land distribution of the two hemispheres). it is likely to make a difference to the frequency and intensity of tornadoes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;No, the mountains would not have to be switched from west to east, because the air flow would simply approximate the mirror image of the northern hemisphere, relative to whichever reflection axis you choose.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your statement that &quot;The predominant airflow in the northern hemisphere is west to east&quot; is only true for &lt;em&gt;mid-latitudes&lt;/em&gt;, about 30 to 45 degrees N or maybe 35 to 50 degrees south.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Without running a climate model it is difficult to be sure, but my guess is that your hypothesis would not yield a 'tornado alley' because there would be less of a driving temperature gradient. There is so much water in the southern hemisphere that the entire hemisphere has a much greater thermal inertia - so no extremes of temperature. Another reason for more stable temperatures is the scarcity of shallow ocean - except for southeastern Asia which is nearly 180 degrees in longitude from a flipped N America.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-10-20T05:10:07.347" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8925" PostTypeId="2" ParentId="8923" CreationDate="2016-10-20T06:22:13.900" Score="2" Body="&lt;p&gt;No, the mountains would still need to be west of tornado alley.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It all starts with temperatures.&#xA;You often hear the colloquial &quot;warm\cold airmass battle&quot; image.&#xA;But more specifically, the vital requirement for tornadoes is warm air advection.  Why?  Because warm advection fundamentally means the proper wind shear (cyclonic turning with height) for sustained storm rotation [for more info on why warm air advection is needed, look into thermal wind].&#xA;To have winds that bring warm air, you have to also have periods with cold air advection too.  Plus the oscillations between warm air and cold air give the potential for uneven vertical temperature profiles to develop, creating instability to fuel vigorous storms.  Warm air advection also builds the instability by transporting in that warm and moisture low level air.&#xA;And then fronts between warm advection zones and cold advection zones brings the trigger to best set off those ripe, unsettled conditions.  So on the warm sides of fronts is the prime location for supercells, though anywhere in warm advection has some potential.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where do you find this battle of warm and cool air masses?&#xA;In the midlatitudes.  The most favorable tornadic regions have to be there, it's the only place with such regular oscillations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And then the most favored spots within that band comes down to the positioning of mountains.&#xA;Mountains help pool the ingredients, and allow upslope flow to perhaps help kick off some of the storms.&#xA;But most importantly, mountain ranges perpendicular to the flow cause consistent lee troughing, the formation of surface lows downwind from the mountains when upper-level storm systems approach.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So it comes back to hich way the winds move in the upper levels of the troposphere in the midlatitudes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And in the southern hemisphere, just as in the northern hemisphere, flow is mostly from the west at midlatitudes [for more on this, look into global or Hadley circulations, particularly the Ferrel cell].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So... indeed, we're talking east of mountains, since the wind is coming from the west.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lee troughing is really important as young storm systems have strong meridional wind ahead of the system (bringing that juicy air in), the largest warm air region size near the low, and falling pressures, which further enhance low-level wind shear [look into isallobaric flow].  Areas further downstream (east) will have more mature systems with less warm advection collocated with instability.  That's a primary reason why the central US has more tornadoes than the eastern US.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then it's all about large bodies of warm water to the right of the upper-level wind, such that it brings in that fuel in when a storm system starts to develop.  Because while warm advection is vital for the wind shear, you still need the moisture for tve precipitation (and to really ramp up instability).  The body of water needs to be warm (to evaporate lots of that water, and help that advection have that vital warming quality) and generally quite large (to provide lots of fuel regardless of slight wind differences, and do so regularly)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, you did well to mention the high deserts\plateaus, as that is a pretty special ingredient to the Southern Plains.  As you may well know, a cap is a pocket of warm air aloft that prevents storm formation.  It's usually up around 850-600 mb, which is up a km or two.  High enough to be above  cloud base but low enough to counteract the nascent updraft energy... and also low enough to be driven by  ground features in other places.&#xA;That cap prevents widespread storms as you said, allowing a rotating storm to mature and persist.  It's a subtle ingredient in that you need just the right amount of it to keep excessive cells down, but not too much such that it prevents all storms.&#xA;It isn't nearly as vital as other features.  But it certainly helps.&#xA;And as you hinted, the best source for a cap is a dry hot elevated region upwind at that wind level (which works out to be to the southwest in the Northern Hemisphere... such that the cap in the southern Plains is primarily due to the Mexican mountains, and in the central Plains based more on the US desert southwest).&#xA;Even without such a region, there can still be natural capping from the mixed layer of the previous day, though.  And even widespread convection can be prolific at tornado producing if shear and instability are strong enough (see April 27th outbreak for instance).  So this isn't as critical as other ingredients.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So again, the order of most important to less important are:&#xA;1 - warm advection (= midlatitides, in spring\fall)&#xA;2 - Downwind of mountains (= east since midlat flow is from west)&#xA;3 - Warm moist water to right (south in NH, north in SH)&#xA;4 - Deserts upwind of capping level wind field (SW in NH, NW in SH)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The best spot is a reasonable balance between each ingredient, though still quite close to each source.&#xA;And that's all the Southern Plains of the US.  Out Oklahoma way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing that actually turns out not to generally be as important is the geography in the cold air direction.  I've definitely heard that one suggested before, but don't see it factoring in much.&#xA;While the amount of land Poleward can help keep cold air drier and allow it to get colder perhaps overall, it's really not the strength of the cold air as much as the existence of it.  Too strong of cold and dry air and you'll have it reaching the warm water source, and disabling moisture return for long periods of time.&#xA;That's why tornado season in the US tends to peak a bit after warmth starts returning.&#xA;You can look at where prolific tornado areas are, too... the Great Plains have a lot of Poleward land; so does a lot of Eurasia, yet it's mostly unfavorable.&#xA;And then conversely, Australia doesn't have a lot of land Poleward yet is still a reasonably busy tornado spot.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mountain ranges Poleward also generally aren't a big deal... even pretty large ones; one of the biggest tornado areas is Bangladesh\India, despite the disruption the Himalayas presents.  Because enough cold air can filter into the region in spite of the blockage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only thing that would be a real large scale geographic issue to the needed cold air would be a warm sea Poleward that modifies the incoming cold air significantly.&#xA;But that's pretty tough to have geographically.  Perhaps more possible in the Autumn... maybe the Great Lakes serves as a slight dampener on fall season tornadoes in parts of the US?  Though their effect is still mostly pretty small overall.  Bring too near any large body of water, in any direction, is really a downer on supercellular tornadoes, as it modifies temperature gradients and instability.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To your direct question... there actually is a very good example of what Tornado Alley would look like in the Southern Hemisphere already: the Pampas Lowlands of Argentina.&#xA;It has that big mountain range to the west, in the midlatitudes, and does have fairly warm water a ways northward.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But it doesn't have quite as large of a region east of the mountains to have the tornadoes in, the cold air (and storm system strength) is probably modified due to the closed nature of the Antarctic vortex and the widespread oceans of the SH modifying air masses, and the source water isn't probably as well located being so far north (and is it warm?).&#xA;But even still, Pampas area might be the second most consistent tornado region on Earth.  Such that some US storm chasers have traveled down there in our winter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the end, local effects play a huge role too, creating mesoscale ingredients (seabreezes\temperature boundaries, upsloping, local vortex flow, etc) to add plenty of rotation to the ledger (see Florida, one of highest tornadoes per square mile in US, in large part due to seabreeze water spouts and hurricanes).  But all things equal, being east of mountains in the midlatitudes is a jackpot ingredient to climatological tornado formation (regardless of hemisphere).&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2016-10-21T22:38:57.473" LastActivityDate="2016-10-21T22:38:57.473" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8926" PostTypeId="1" CreationDate="2016-10-20T11:40:00.687" Score="3" ViewCount="980" Body="&lt;p&gt;Specifically, what time period would it take for obsidian as opposed to basalt, to form? (I need to know how much faster obsidian cools than basalt.)&lt;/p&gt;&#xA;" OwnerUserId="6817" LastEditorUserId="725" LastEditDate="2016-10-24T15:34:34.297" LastActivityDate="2016-10-24T15:55:25.777" Title="What does &quot;rapid&quot; mean in terms of igneous rock formation?" Tags="|igneous|world-building|time|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="8927" PostTypeId="1" AcceptedAnswerId="9270" CreationDate="2016-10-20T12:18:23.170" Score="5" ViewCount="556" Body="&lt;p&gt;I'm looking for a dataset (in pretty much any format) of soil texture according to USDA classification (by U.S. Department of Agriculture). Is there anything that would cover the entirety of Europe? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found the &lt;a href=&quot;http://esdac.jrc.ec.europa.eu/content/topsoil-physical-properties-europe-based-lucas-topsoil-data#tabs-0-description=1&amp;amp;tabs-0-description-2=&quot; rel=&quot;nofollow noreferrer&quot;&gt;Topsoil physical properties for Europe (based on LUCAS topsoil data)&lt;/a&gt; dataset from the European Soil Data Centre (ESDAC), which would suit my needs perfectly, except that it only covers the EU member countries and thus some countries are missing.&lt;/p&gt;&#xA;" OwnerUserId="6643" LastEditorUserId="6643" LastEditDate="2017-06-28T08:44:26.610" LastActivityDate="2018-02-16T09:43:09.657" Title="European soil texture dataset according to USDA classification" Tags="|soil|geospatial|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8928" PostTypeId="1" CreationDate="2016-10-20T23:17:58.463" Score="1" ViewCount="246" Body="&lt;p&gt;I came across this question while studying in my text book: What does the existence of strata containing a reverse fault and above them parallel strata refer to? I thought that referred to an angular unconformity, thinking that the fault should make a tilt in the layers, and that the tilts which appear in angular unconformity happen by a fault or a fold, but I found that the answer is &quot;disconformity&quot;, so I became confused. Would that reverse fault present only a crack not a tilt? Or was the strata where the fault appeared was parallel so the movement didn't affect the angle of the layers? Would the tilt which appears in angular unconformities happens by other factors more than a fault and a fold?. I would like anyone to help me understand this, because I didn't get help searching in many websites but some definitions and concepts which made me more perplexed.&lt;/p&gt;&#xA;" OwnerUserId="6820" LastEditorUserId="111" LastEditDate="2016-10-21T01:35:21.693" LastActivityDate="2016-10-21T01:35:21.693" Title="Do reverse faults tilt the underlying layers of rocks to form an angular unconformity?" Tags="|geology|homework|structural-geology|geologic-layers|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8929" PostTypeId="2" ParentId="8874" CreationDate="2016-10-21T03:37:06.603" Score="3" Body="&lt;p&gt;Latent heat is released when water vapor turns to liquid\solid water.  So latent heat is released where there is precipitation.  So you're looking primarily at places where there is lots of moist convection... the ITCZ near the equator and then the midlatitudes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would believe that all of that latent heat release aloft should mean more heat is moved Poleward in the upper atmosphere branches of global circulation than would be moved by dry convection.  And would therefore make the circulation more efficient, perhaps having a long-term effect of allowing reduced horizontal wind magnitudes in comparison to a dry world (the resulting reduction in instability means weaker updrafts and the better transport Poleward means smaller temperature\pressure imbalances and thus less wind than a world without moisture).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Offhand I don't know the literature well... Google Scholar helps though you run into a lot of climate model parameterization articles using most terms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://eaps4.mit.edu/research/Lorenz/Nature_of_the_Global_Circulation_1969.pdf&quot; rel=&quot;nofollow&quot;&gt;The nature of the global circulation of the atmosphere&lt;/a&gt; should be fairly stalwart, as Lorenz was pretty big in the field I believe.  It talks about how latent heat in the tropics enhances the updraft winds in the ITCZ on page 17 a small bit.  The paper seems to suggest it would increase the global circulation strength by increasing those velocities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0469(1989)046%3C2957:ROTHCT%3E2.0.CO%3B2&quot; rel=&quot;nofollow&quot;&gt;Response of the Hadley Circulation to Convective Forcing in the ITCZ&lt;/a&gt;&#xA;looks like it might have potential too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My most successful search term set seemed to be&#xA;&lt;a href=&quot;https://www.google.nl/search?q=&amp;quot;global+circulation&amp;quot;+&amp;quot;latent+heat&amp;quot;+-simulation+-co2&quot; rel=&quot;nofollow&quot;&gt;&quot;global circulation&quot; &quot;latent heat&quot; -simulation -co2&lt;/a&gt;&#xA;though it still wasn't amazing.  But probably some other good articles to find if you thumb through them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm certainly not a top expert in the field, but hope these thoughts and links add at least a little potential help or a starting point for you.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2016-10-22T04:16:34.000" LastActivityDate="2016-10-22T04:16:34.000" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8930" PostTypeId="1" CreationDate="2016-10-21T08:41:04.757" Score="4" ViewCount="167" Body="&lt;p&gt;A documentry stated that during the Permian asteroid strike the atmosphere heated up to above 400C, potentially to 600C. As this would ignite most of the biomass, including us, I wondered if this fire would consume so much atmospheric oxygen that it would kill most animal life that survived the fire. Oxygen levels would only need to fall below about 10 percent for this to happen.&lt;/p&gt;&#xA;" OwnerUserId="6823" LastEditorUserId="2536" LastEditDate="2016-10-21T11:07:11.493" LastActivityDate="2016-10-26T17:45:18.863" Title="Percentage of Oxgen left after burning all the available biomass" Tags="|mass-extinction|oxygen|biomass|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8931" PostTypeId="1" AcceptedAnswerId="8935" CreationDate="2016-10-21T12:52:23.670" Score="3" ViewCount="125" Body="&lt;p&gt;Where do companies like Google and Yahoo and Mapquest get their street and road data? Is this a data source that the public has access to?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastEditorUserId="192" LastEditDate="2016-10-21T20:13:27.823" LastActivityDate="2016-10-21T20:13:27.823" Title="Street and road data" Tags="|geography|open-data|mapping|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8932" PostTypeId="1" CreationDate="2016-10-21T13:04:47.927" Score="6" ViewCount="251" Body="&lt;p&gt;I came across a question in my notes about why the actual thickness of permafrost is much less than the theoretical maximum possible permafrost thickness value.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The actual permafrost measure on sites were much less thick than the maximum possible thickness.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the actual permafrost thickness had values ranging from 0-15m. But the maximum possible permafrost thickness had values froom 75, to 375m. We determined the maximum possible thickness by using the formula $z=(T_s)(k/q)$. With $T_s$ which was -3 and we took the absolute value of this so 3. Then K was the thermal conductivity $W/m$ and Q was the heat flux which was $.04w/m^2$. So why was the actual thickness much less than the theoretical max possible? Clearly the max possibly max is going to be higher than the actual thickness because this gives a end range for the thickness of the permafrost but besides that I am not quite sure  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: as an example, the following values are for Newfoundland and Labrador.  The maximum possible thickness was calculated by that equation I gave up above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Material, Max Possible Thickness, Actual Permafrost Thickness:&lt;br&gt;&#xA;granite, 75m, 0m&lt;br&gt;&#xA;sandstone, 150m, 1m,&lt;br&gt;&#xA;glacial till, 113m,1m&lt;br&gt;&#xA;esker gravel, 188m,0m&lt;br&gt;&#xA;marine silt, 375m,15m&lt;br&gt;&#xA;river sand, 225m, 0m&lt;br&gt;&#xA;fen peat, 300m, 10m&lt;/p&gt;&#xA;" OwnerUserId="6825" LastEditorUserId="534" LastEditDate="2016-10-22T15:11:06.077" LastActivityDate="2016-11-22T13:05:28.997" Title="Actual thickness of permafrost vs theoretical maximum possibly permafrost thickness" Tags="|geology|geography|permafrost|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8934" PostTypeId="2" ParentId="8913" CreationDate="2016-10-21T15:16:55.193" Score="3" Body="&lt;p&gt;Judging by the general quality of the first graph, I don't think that it is the most reliable source. However as I don't feel like reading trough all papers, I will accept the numbers as they are stated. However once you include uncertainties of the observed residence time, I would assume most of the studies are not significantly different from each other. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The variability in the calculated residence time can be due various reasons; the measurement location, the number of observations used and the length of  the observational record. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The measurement location is probably the most important source of variation as results may vary a lot depending on where you measure. Multiple observation locations measuring what is called background air masses would be needed to get a good indication of the global average residence time of $CO_2$ in the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would say you are spot on with the complicating factors. &#xA;Local influences are important as $CO_2$ emissions have different radiocarbon signatures depending on their origin. $CO_2$ from fossil fuel burning contains no radiocarbon while the nuclear industry emits low amounts of pure $^{14}C$ (not necessarily in the form of $^{14}CO_2$ though). The natural sources and sinks of $CO_2$ (biosphere and ocean) are also not in equilibrium with the atmosphere since the atomic bomb tests in 1950s and 1960s. Immediately after the bomb tests, the large amount of $^{14}C$ produced in the atmosphere meant that it was enhanced in  $^{14}CO_2$ compared to the biosphere and the ocean. Since then, $^{14}CO_2$ has decreased in the atmosphere, as it was taken up by the biosphere ant the oceans. This lead to an such a large increase in  $^{14}C$  in the biosphere and the surface ocean, that they are now enhanced compared to the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This &lt;a href=&quot;https://e-reports-ext.llnl.gov/pdf/636052.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;graph&lt;/a&gt; including the oceans should explain what I mean. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xQ2I5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xQ2I5.png&quot; alt=&quot;Radiocarbon signature in ocean and atmosphere.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6826" LastActivityDate="2016-10-21T15:16:55.193" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8935" PostTypeId="2" ParentId="8931" CreationDate="2016-10-21T18:16:34.277" Score="7" Body="&lt;p&gt;Google Maps and MapQuest have gathered data and information through subcontractors and their own internal efforts. Their information is proprietary and is very hard to gain access to (and most methods of scraping this data would violate their Terms of Service). It's generally not considered a reliable source for getting anything beyond geocoded addresses. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;An alternative method for getting more specific geographic data (e.g. building footprints, forest extents, roads/highways, POIs, etc.) is through the &lt;a href=&quot;https://www.openstreetmap.org/about&quot;&gt;OpenStreetMap Project&lt;/a&gt;. This information is Open and crowd-sourced with very few limitations. Specific information can be grabbed through their &lt;a href=&quot;http://www.overpass-api.de/&quot;&gt;Overpass API&lt;/a&gt; or can be &lt;a href=&quot;http://download.geofabrik.de/&quot;&gt;downloaded as a whole&lt;/a&gt; in their pbf format which can then be converted to shapefile/GML.&lt;/p&gt;&#xA;" OwnerUserId="5536" LastEditorUserId="192" LastEditDate="2016-10-21T20:13:04.530" LastActivityDate="2016-10-21T20:13:04.530" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8936" PostTypeId="2" ParentId="8932" CreationDate="2016-10-22T12:34:53.833" Score="1" Body="&lt;p&gt;I could not recover my account so here is some additional information for you. This area is Newfoundland and Labrador.  The maximum possible thickness was calculated by that equation I gave up above&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Material, Max Possible Thickness, Actual Permafrost Thickness:&lt;br&gt;&#xA;granite, 75m, 0m&lt;br&gt;&#xA;sandstone, 150m, 1m,&lt;br&gt;&#xA;glacial till, 113m,1m&lt;br&gt;&#xA;esker gravel, 188m,0m&lt;br&gt;&#xA;marine silt, 375m,15m&lt;br&gt;&#xA;river sand, 225m, 0m&lt;br&gt;&#xA;fen pea,t 300m, 10m&lt;/p&gt;&#xA;" OwnerDisplayName="user6834" LastActivityDate="2016-10-22T12:34:53.833" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="8937" PostTypeId="2" ParentId="8516" CreationDate="2016-10-22T14:37:07.060" Score="3" Body="&lt;p&gt;I think the short answer to your question is &quot;yes&quot;. Getting into the specifics though, it's a lot more complicated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can't speak to the specific RF and atmospheric interactions, but the changes to weather patterns and long-term climatic anomalies from climate change have been well established by climatologists. From my understanding, the issue with focusing specifically on land-atmospheric interactions at one altitude in the lower troposphere is that topography, land/water cover, latitude and existing weather patterns will have a more dominant effect and it'll be effectively impossible to determine changes based solely on RF anomaly. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For more info, it might make more sense to look over the &lt;a href=&quot;http://ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_TS_FINAL.pdf&quot; rel=&quot;nofollow&quot;&gt;IPCC AR5 Working Group 1 Technical Summary Report&lt;/a&gt;. Chapters TS.2 and TS.4 would probably have some specifics that could help clarify things.&lt;/p&gt;&#xA;" OwnerUserId="5536" LastActivityDate="2016-10-22T14:37:07.060" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8938" PostTypeId="2" ParentId="8932" CreationDate="2016-10-22T14:47:47.873" Score="1" Body="&lt;p&gt;I resolved the following based on your input:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$z = (T_s)(k/q)$ for the granite case, &lt;/p&gt;&#xA;&#xA;&lt;p&gt;where&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$75 = (3)(k/0.04)$ where $k = 1$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;so based on this site &lt;a href=&quot;http://www.engineeringtoolbox.com/thermal-conductivity-d_429.html&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt;, typical granite thermal conductivity is in the range of 1.7 to 4 $W/m K$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We could say your site is special with $k=1$ maybe local conditions..&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's test the Esker gravel, where the aforementioned site propose $k=0.7$ for a typical value for gravel. Let's see your model&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$188 = (3)(k/0.04)$ where $k = 2.5$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;to balance the equation here you need a value of $k$ that is larger,  can't be local factors explaining that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So how to approach this ?&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;the soil temperature $T_s$ cannot be fixed. It should vary a lot depending on your environment, and also even in a single environment you could have variations when considering other factors such as the moisture, the slope, the albedo, the snow conditions, the vegetation (eg: &lt;a href=&quot;http://www.nrcresearchpress.com/doi/abs/10.1139/e04-082&quot; rel=&quot;nofollow&quot;&gt;n-factors&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;the heat flux at 0.04 is usually a regional estimation. While not impossible, I found this value low. In the Appalachians (Chic-Chocs) values where estimated to be around $2 W/m^2$ &lt;/li&gt;&#xA;&lt;li&gt;You need better estimations for $k$ for this this to work&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Overall, your equation to resolve the depth is quite simple and do not take into account a lot of factors, and some important parameters which are generalized /estimated broadly weaken your results.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastEditorUserId="1411" LastEditDate="2016-10-23T12:59:41.543" LastActivityDate="2016-10-23T12:59:41.543" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8940" PostTypeId="1" CreationDate="2016-10-22T22:40:16.223" Score="0" ViewCount="81" Body="&lt;p&gt;Came across the following problem on a question sheet. At its maximum level following deglaciation, approx 11,000 years ago, Lake Melville flooded the Sebaskachu River valley to an elevation of 135m above sea level. However the upper reaches of the Mulligan River and its tributaries were not flooded by Lake Melville. The tributaries of the Sebaskachu River above 135m elevation were not flooded also. What differences in river geomorphology exist between the higher river systems and the Sebaskachu River below 135m? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know river morphology isused to describe the shapes of river channels and how they change in shape and direction over time. It is a function of a number of processes and environmental conditions, including the composition and erodibility of the bed and banks.Erosion comes from the power and consistency of the current, and can effect the formation of the river's path&lt;/p&gt;&#xA;" OwnerUserId="6838" LastActivityDate="2016-10-23T00:24:17.107" Title="Flooding lakes in geography" Tags="|geology|rivers|geomorphology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8941" PostTypeId="2" ParentId="8940" CreationDate="2016-10-23T00:24:17.107" Score="1" Body="&lt;p&gt;I've never heard of the 'Mulligan river', and neither, apparently has Google Earth, (apart from the Australian Mulligan). However, there are some obvious features of the Sebaskatchu River on Google Earth that one might note. As background, 11,000 years ago the Earth was just beginning to emerge from the last ice age, so ice cover was very much greater, and sea level was very much lower, so I assume that the +135 metre lake level to which you refer is relative to today's sea level, consisting of a temporary glacially dammed lake level. These ancient lake shore lines are a common feature of glaciated terrain, as may be seen in Alaska, Scotland, Norway and New Zealand. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;All lakes are relatively short-lived in geological terms, being effectively sediment traps. Sediment accumulation in the lower Sebaskatchu river basin has been intense, and has all but filled the entire lower basin. This is most obvious from the extreme river meandering, which occurs only wherever there is a high sediment load combined with a low hydraulic gradient.  There are two phases of sediment fill - a general fill over a large area, and a specific small lake fill which you can see about 6 km (as the crow flies) from the river mouth, and for about 8 km further upstream.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You may note that none of the lower basin drainage is guided by the bedrock, whereas the upper basin, presumably above your threshold of +135m, is of a different style, This upper drainage is partly guided by the underlying rock structure, i.e. along strike, and partly by a cross-cutting component. The latter is most likely 'superimposed drainage', which has cut down through ice and glacial drift into the bedrock. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-10-23T00:24:17.107" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8942" PostTypeId="2" ParentId="8819" CreationDate="2016-10-23T02:56:59.927" Score="7" Body="&lt;p&gt;Skimming the paper, I believe the relevance of the wind stress curl is its relation to &quot;Ekman pumping&quot;. I haven't found a simple, concise reference for this, but &lt;a href=&quot;http://paoc.mit.edu/labguide/ekpump.html&quot;&gt;this page&lt;/a&gt; might be a good start, and &lt;a href=&quot;https://marine.rutgers.edu/dmcs/ms501/2004/Notes/Wilkin20041028.htm&quot;&gt;this page&lt;/a&gt; has a couple of formulas about wind stress curl. I'll try to summarize here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When wind blows over water, the top of the water starts moving. It shears against the water below it, so that water starts moving too. The momentum from the wind is transferred down into lower layers of the water. This water also feels the Coriolis force. The direction it ends up moving in depends on the balance of friction/drag and Coriolis force. On average, the water moves to the right of the wind in the northern hemisphere; if the wind is blowing northward, the water moves eastward.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now imagine you have strong wind blowing northward at one location and weaker wind to the right of it. The water at the first location moves to the right, and it does so faster than the water at the second location (because the wind forcing the water is stronger at the first location). The water converges at the second location, pushing the water downward. This is how the curl of the wind stress (the northward wind changing in the east-west direction) is related to the water convergence (the eastward current changing in the east-west direction) and hence to water being pushed down or pulled up. Positive wind stress curl pulls water up; negative wind stress curl pushes it down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The last relevant part here is that this kind of motion suppresses ocean mixing. The relevant sentence from that paper is&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The wind stress curl and hence Ekman pumping anomalies were negative, which also is consistent with relatively weak entrainment.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&quot;Entrainment&quot; is how much of the deep, cold ocean water mixes with the relatively warm upper ocean water, cooling it. The negative wind stress curl leads to water being pushed down and less deep water mixing with the upper ocean. The upper ocean stayed warmer, so the whole heat blob lasted longer.&lt;/p&gt;&#xA;" OwnerUserId="1342" LastActivityDate="2016-10-23T02:56:59.927" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8943" PostTypeId="1" AcceptedAnswerId="8945" CreationDate="2016-10-23T06:35:35.730" Score="8" ViewCount="261" Body="&lt;p&gt;In this Chemistry question &lt;a href=&quot;https://chemistry.stackexchange.com/q/49280/16035&quot;&gt;Is there any reason to fear personal exposure to rain with a pH of 3.1?&lt;/a&gt; I haven't gotten any answer, but there was some discussion about the reality of the measurement. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I'll ask here, is a sustained rainfall with a pH of roughy 3.1 possible on Earth? Of course it would have to be related to some serious sources of pollution - perhaps intensive coal burning over a large geographic region. I say 'sustained' to rule out any fluke or highly unusual situations. Could I really fill a plastic bucket with a substantial amount of pH 3.1 water by putting it outdoors, under the sky, in the rain, in the right place on Earth?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oh, for this question I'd like to exclude unusual situations related to volcanic eruptions as well. &lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2017-04-13T12:57:06.283" LastActivityDate="2016-10-23T19:50:29.107" Title="Could a reported rainfall pH of 3.1 actually be realistic?" Tags="|rainfall|air-pollution|acid-rain|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8944" PostTypeId="2" ParentId="8943" CreationDate="2016-10-23T17:48:29.803" Score="7" Body="&lt;p&gt;Raindrops gain a small amount of acidity as they fall through carbon dioxide in the air, but that's not what this question is about. Raindrops commonly start off as ice crystals which have to nucleate around something, usually an aerosol particle such as soot, clay, bacteria, sulphur dioxide , dimethyl sulphide, etc. If a small raindrop nucleates around an acidic core, then a pH of 3.1 is certainly possible. Much depends upon the raindrop size. With a larghe raindrop - up to about 4 mm maximum (it breaks up if any larger) there is likely to be huge dilution, whereas in a very small raindrop, as in a fine mist, there can be minimal dilution, and maximal acidity.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-10-23T17:48:29.803" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8945" PostTypeId="2" ParentId="8943" CreationDate="2016-10-23T19:50:29.107" Score="8" Body="&lt;p&gt;A quick literature search seems to confirm Gordons estimation, even at the scale of a whole bucket:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;[T]he annual mean pH, based upon&#xA;  samples collected weekly during 1970-1971 and weighted proportionally to&#xA;  the amount of water and pH during each period of precipitation, was 4.03&#xA;  at the Hubbard Brook Experimental Forest, New Hampshire; 3.98 at Ithaca,&#xA;  New York; 3.91 at Aurora, New York; and 4.02 at Geneva, New York. Measurements&#xA;  on individual rainstorms frequently showed values between pH 3&#xA;  and 4 at all of these locations. Data from the National Center for Atmospheric&#xA;  Research included precipitation pH values as low as 2.1 in the northeastern&#xA;  United States during November 1964. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Patel, C. K. N., E. G. Burkhardt, and C. A. Lambert. &quot;Acid rain: a serious regional environmental problem.&quot; Science 184 (1974): 1176-1179.&lt;/p&gt;&#xA;" OwnerUserId="2861" LastActivityDate="2016-10-23T19:50:29.107" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8946" PostTypeId="1" CreationDate="2016-10-23T23:37:34.137" Score="2" ViewCount="1701" Body="&lt;p&gt;Soil forming factors can include climate, parent material, vegetation, animal activity, fire and influence by humans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have investigated a podzol soil profile with horizons LFH, AH, AE, BF and parent material.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can see how climate would affect the LFH, AH AND AE. Precipitation has caused these horizons to be cohesive and climate has provided a growing period for plants, which has caused a presence of organic materials in these layers.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Vegetation has also played a role in the LFH, AH and AE. The roots of plants and trees have caused a presence of organic materials in these horizons.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not quite sure if animal activity has played a role in the soil profile. Besides the decomposition of bodies and the fertilization by faeces, I am not sure if animal presence has played any more of a role than this. There was also no evidence of fire in these horizons that I witnessed.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;My question is, if animal presence is a contributing factor, what horizons would it play a role in?&lt;/strong&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Also, I'm not quite sure how humans or parent material have influenced soil profile. Looking for some guidance with this.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6840" LastEditorUserId="2470" LastEditDate="2016-10-27T02:26:04.143" LastActivityDate="2016-10-27T02:53:36.747" Title="Factors Affecting Soil Profile" Tags="|geology|geography|soil|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8947" PostTypeId="1" CreationDate="2016-10-24T08:47:18.753" Score="0" ViewCount="286" Body="&lt;p&gt;I am looking for any academic reference (i.e. articles) regarding the time of concentration for large and small basins.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;E.g. I would expect that a large basin (area &gt; 1,500 km^2) will flood (or reach its max peak flow) later in time (e.g. 1-2 days later) when compared to a small basin if the same amount of rain will fall in both of them.&lt;/p&gt;&#xA;" OwnerUserId="6841" LastEditorDisplayName="user1161" LastEditDate="2017-07-03T02:46:53.157" LastActivityDate="2018-09-15T14:18:03.223" Title="Time of concentration - Difference between large and small basins" Tags="|geology|hydrology|geography|reference-request|flooding|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8948" PostTypeId="1" AcceptedAnswerId="8950" CreationDate="2016-10-24T13:31:39.147" Score="2" ViewCount="231" Body="&lt;p&gt;I am looking for an explanation for this warm pool of water in the North and North East Bay of Bengal - &lt;a href=&quot;https://earth.nullschool.net/#2016/10/22/0000Z/ocean/surface/currents/overlay=sea_surface_temp_anomaly/orthographic=-277.79,16.82,622/loc=88.763,16.670&quot; rel=&quot;nofollow noreferrer&quot;&gt;North Bay Warm Water Anomaly&lt;/a&gt;. Currently the path of the sun is towards the southern hemisphere and we are in the fourth week of October. In contrast there are no warm SSTs along the North Arabian Sea. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it possible that warm water from the equator has moved up North along the eastern wall of the Bay of Bengal ? Is that indicated by the gyres on display on the Earth Null site ? I observe that there is a warm pool along the eastern seaboard near the equator(negative Indian Ocean Dipole) - &lt;a href=&quot;http://stateoftheocean.osmc.noaa.gov/sur/ind/dmi.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;IOD Index&lt;/a&gt;. Is it possible to show (if my guess is correct) that there is a south to north pressure gradient that is moving warm water north(ageostrophic circulation)  ? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QnPyn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QnPyn.png&quot; alt=&quot;Weekly SST Global Anomaly&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see the weekly SST global anomaly as well shows a warm pool anomaly in the North Bay of Bengal.  &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2016-10-24T15:36:49.253" LastActivityDate="2016-10-26T11:15:21.947" Title="North Bay of Bengal warm pool anomaly" Tags="|ocean|oceanography|water|ocean-currents|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8949" PostTypeId="2" ParentId="8926" CreationDate="2016-10-24T15:55:25.777" Score="4" Body="&lt;p&gt;Obsidian is volcanic glass of &lt;em&gt;felsic&lt;/em&gt; composition (i.e. SiO&lt;sub&gt;2&lt;/sub&gt;-rich) whereas basalt is a volcanic rock which may or may not be (partially) glassy of &lt;em&gt;mafic&lt;/em&gt; composition (i.e. SiO&lt;sub&gt;2&lt;/sub&gt;-poor). So when you're saying&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;obsidian as opposed to basalt&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;...you're comparing apples and oranges. So instead of discussing obsidian versus basalt, let's discuss &lt;em&gt;phaneritic&lt;/em&gt; versus &lt;em&gt;aphanitic&lt;/em&gt; versus &lt;em&gt;glassy&lt;/em&gt; rocks, in the context of being melted by dragons (because that's what you're asking in your question).&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Phaneritic rocks are those with coarse crystals, easily observable to the naked eye. The best example is granite, like the stuff you see in pavements and kitchen tops. These rocks form by slow underground cooling so this is not something that dragons can make.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Aphanitic rocks are those with very fine crystals that are only visible with a microscope. Basalt is the most obvious example. To the naked eye they may look like glassy, but they do not have the characteristic conchoidal fractures you see in obsidian.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Glassy rocks (that I'm pretty sure have a fancy name that starts with &lt;em&gt;hyalo&lt;/em&gt;, I just can't remember what it is) have no crystals in them so they're basically glass. Obsidian is the best example.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Note that there could be combinations of those, just to confuse you even more: for example you can have aphanitic rocks with large crystals of minerals (known as porphyritic textures) or a rock that's mostly glass but has some crystals floating around in it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you have dragons melting rocks, the cooling of the rock is done very rapidly in air. This can be minutes to hours, depending on the size of the block being melted. This is definitely rapid enough to form rocks. But, the final form of the rock also depends on the chemical composition. Felsic rocks have very high viscosities and low diffusion rates, and even relatively slow cooling (days?) can form obsidian. That's actually the reason that obsidian is most common in felsic rocks. Mafic rocks, on the other hand, require very rapid cooling to form glass (for example, &lt;a href=&quot;https://youtu.be/hmMlspNoZMs&quot; rel=&quot;nofollow&quot;&gt;erupting into water&lt;/a&gt;), and even then they make have some &quot;quench&quot; crystals of olivine or pyroxene.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Felsic rocks also have lower melting points than mafic rocks. This all leads to the conclusion:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Yes, dragons can make obsidian, and it's quite easy&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take a granite (or even sand-bearing mud), melt it with some dragon fire, and let it just cool. The high SiO&lt;sub&gt;2&lt;/sub&gt; content will make the melting point rather low (let's say below 1000 °C). The high viscosity will ensure that it stays where it is rather than flow somewhere else (think of &lt;a href=&quot;https://youtu.be/_GSp6lPlel4&quot; rel=&quot;nofollow&quot;&gt;basalt flows of Hawaii&lt;/a&gt; versus &lt;a href=&quot;https://youtu.be/h6B1myUKAS4&quot; rel=&quot;nofollow&quot;&gt;Mt St Helens felsic lava domes&lt;/a&gt;). Obsidian will surely form.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-10-24T15:55:25.777" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8950" PostTypeId="2" ParentId="8948" CreationDate="2016-10-24T16:55:21.720" Score="2" Body="&lt;p&gt;I think the Southeastern Tropical Indian Ocean &lt;a href=&quot;http://stateoftheocean.osmc.noaa.gov/sur/ind/setio.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;(SETIO)&lt;/a&gt; provides a better hint of what might be happening. It clearly shows a positive pattern since last November. &lt;a href=&quot;https://i.stack.imgur.com/gDUWD.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gDUWD.gif&quot; alt=&quot;SETIO NOAA&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;http://stateoftheocean.osmc.noaa.gov/sur/ind/wtio.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think it might be related to the recovery from the intense 2015 El Niño. If I remember from &lt;a href=&quot;http://dx.doi.org/10.1175/1520-0442(2003)016%3C0003:AOVITI%3E2.0.CO;2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lau &amp;amp; Nath, 2003&lt;/a&gt;, when you have a warm ENSO, you get a reduction of the Monsoon intensity with lower wind speeds, which results in a reduction of sensible and latent heat loss. Also, the  cloud cover is reduced because of dryer conditions, which results in a larger percentage of the shortwave radiation reaching the ocean surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://stateoftheocean.osmc.noaa.gov/sur/ind/wtio.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;WTIO&lt;/a&gt; seems pretty normal currently, so it suggest the conditions are mostly eastern Indian Ocean related. The &lt;a href=&quot;http://bulletin.aviso.oceanobs.com/images/duacs_global_nrt_msla_merged_h_latest_glo_msla_n0_t0.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;altimetry sea surface height anomaly&lt;/a&gt; seems to suggest the currents are counterclockwise in the Bay, so the anomaly seems to be a regional effect.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="6093" LastEditDate="2016-10-26T11:15:21.947" LastActivityDate="2016-10-26T11:15:21.947" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8951" PostTypeId="2" ParentId="8516" CreationDate="2016-10-24T17:33:49.647" Score="7" Body="&lt;p&gt;First, regarding your assumptions, here is a graphic from &lt;a href=&quot;http://www.goes-r.gov/users/comet/tropical/textbook_2nd_edition/print_1.htm&quot; rel=&quot;noreferrer&quot;&gt;this online textbook&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/C4lyS.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/C4lyS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, your first assumption is correct, surface radiation is much more significant than thermals. Your second assumption is also correct, 'Back Radiation' and 'Emitted by Atmosphere' flows are significant, but absorption of heat by the ground from the air isn't even featured on this chart. So conductive heat transfer from air to ground is negligible. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This &lt;a href=&quot;http://earthobservatory.nasa.gov/Features/EnergyBalance/page7.php&quot; rel=&quot;noreferrer&quot;&gt;page&lt;/a&gt; gives some good background on how carbon dioxide contributes to global warming, and, as you said, it is due to absorption of infra-red radiation from both the ground and the air. Specifically, CO$_2$ absorbs IR wavelengths that can 'escape' absorption in water vapor (the primary greenhouse gas) in the range 12-15 $\mu$m, as shown in the graphic below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/h8EOg.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/h8EOg.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With more thermal radiation absorbed in the air, less escapes into space, and the net energy balance of Earth is positive which results in a slow and steady warming. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-10-24T17:33:49.647" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8952" PostTypeId="1" AcceptedAnswerId="8953" CreationDate="2016-10-24T17:38:37.203" Score="5" ViewCount="140" Body="&lt;p&gt;So, imagine a new technology were introduced that was incredibly efficient at carbon sequestration, lets say removal of ~90% of carbon in processed air and processing 10 tons of gas per minute (these numbers can be fudged, the basic gist is extreme carbon sequestration that would be visible on a global scale in a very short order of time, like, less than a decade or so).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth is warming, and it's obvious in our longer spring/fall seasons and shorter winters. If we were to quickly remove atmospheric CO2 using the above mcguffin, would the seasons revert to pre-industrial levels relatively quickly, or would earth have trapped a significant amount of solar energy that would need to radiate away before we began to see normal seasons?&lt;/p&gt;&#xA;" OwnerUserId="5673" LastActivityDate="2016-10-26T12:10:30.040" Title="Would ultra-efficient carbon sequestrion produce immediate results in global temperatures?" Tags="|climate-change|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8953" PostTypeId="2" ParentId="8952" CreationDate="2016-10-24T20:13:32.687" Score="9" Body="&lt;p&gt;The issue of the lag time between carbon addition to the atmosphere and maximum warming that results from it, is probably pretty divisive. I had previously heard estimates around 50 years, but the most recent work I could find (that was available for free) &lt;a href=&quot;http://iopscience.iop.org/article/10.1088/1748-9326/9/12/124002;jsessionid=669174B25B26A1C276408EA23540AC3E.c4.iopscience.cld.iop.org&quot; rel=&quot;nofollow noreferrer&quot;&gt;indicates&lt;/a&gt; that 10 years is about right, with Figure 1 of the linked paper being the best graphical evidence. This 10 year response is for a one-off injection of carbon, so we can't assume it would work the same for a one-off removal of carbon, but we can go with that number for now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JkJUM.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JkJUM.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, looking at Figure 1, if we started rapidly removing carbon from the atmopshere, the temperatures should reflect within a year or two, and if we removed ALL of the anthropogenic delta-CO$_2$, we could expect temperatures to go back to pre-industrial revolution plus or minus any natural changes since then in about 10 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A side note: supposing we could sequester as much carbon as we put into the atmosphere every year. That would be great! But how much energy would it take to sequester that carbon? And where would we get the energy to sequester the carbon. Sequestration seems like a great idea, but I don't think it would work, even if an excellent method of sequestration could be found, until the world's energy demands are met from non-fossil fuel sources. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="6703" LastEditDate="2016-10-26T12:10:30.040" LastActivityDate="2016-10-26T12:10:30.040" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8956" PostTypeId="1" AcceptedAnswerId="9062" CreationDate="2016-10-26T13:50:40.127" Score="3" ViewCount="1956" Body="&lt;p&gt;Tides observations everywhere show that spring tides occur not at full or new moon, at the time of maximum driving forces, but typically a day or two later.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What causes this delay?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2016-11-08T22:01:39.280" LastActivityDate="2016-11-08T22:01:39.280" Title="Why don't spring tides occur at full/new moon (age of tide)?" Tags="|ocean|oceanography|tides|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8957" PostTypeId="1" AcceptedAnswerId="8962" CreationDate="2016-10-26T14:06:03.223" Score="6" ViewCount="560" Body="&lt;p&gt;I was wondering whether there are any uranium deposits in the ocean floor, or in the rock walls of the continental shelf, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was hoping to have some deep sea uranium deposits accessible from the water, for fiction writing. So I would like to know if such has ever been found, or if it's possible to have uranium deposits so near to the ocean.&lt;/p&gt;&#xA;" OwnerUserId="6853" LastActivityDate="2017-08-15T13:01:02.423" Title="Uranium Deposits in the Ocean?" Tags="|geology|ocean|oceanography|uranium|sea-floor|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8958" PostTypeId="1" AcceptedAnswerId="8965" CreationDate="2016-10-26T14:56:14.233" Score="0" ViewCount="394" Body="&lt;p&gt;What could have caused the Sun to appear to have stopped shining from noon 'till 3 in the afternoon? According to the Bible, at Jesus' crucifixion, darkness covered the land because the sun stopped shining from noon 'till 3 in the afternoon. What could have caused this phenomena? I know it couldn't be a solar eclipse, since they don't last that long and there weren't any on April 3rd of 33 AD (date of Crucifixion, see &lt;a href=&quot;http://bible.wikia.com/wiki/User:AChildOfGod/Death_of_Jesus&quot; rel=&quot;nofollow&quot;&gt;here&lt;/a&gt; for why). So what known phenomena might have caused this said darkness?&lt;/p&gt;&#xA;" OwnerUserId="4864" LastEditorUserId="4864" LastEditDate="2016-10-28T14:19:05.797" LastActivityDate="2016-10-28T14:19:05.797" Title="Sun Appearing to have Stopped Shining" Tags="|meteorology|climatology|sun|" AnswerCount="1" CommentCount="10" ClosedDate="2016-10-27T07:42:06.683" ContentLicense="CC BY-SA 3.0" />
  <row Id="8959" PostTypeId="2" ParentId="8917" CreationDate="2016-10-26T15:32:17.977" Score="2" Body="&lt;p&gt;The perigean spring tides arise when the spring tide occurs during the time of shortest distance between Moon and Earth. As the full moon on October 15-16, 2016 occurred near perigee, then it can be consider a &lt;a href=&quot;http://earthsky.org/tonight/first-of-three-supermoons&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;supermoon&quot;&lt;/a&gt; even if the difference in Moon size was not that great. The fact is that the October full moon was not even the largest of the year; that will occur in November: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The November 14, 2016 full moon – closest and largest full moon is 2016 – will also be the largest full moon thus far in the 21st century (2001 to 2100). It’ll be the closest encounter between the Earth and moon until November 25, 2034.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Thus, the mid-October was exceptional in a sense, but will be surpassed by the  November event.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regard to the effect on tides, the combination of the $M_2$ and $S_2$ tidal constituents gives rise to the spring/neap cycle. Meanwhile, the $N_2$ tidal constituent arises from the fluctuating distance of the Moon from Earth and its frequency is 1 cycle/month less than that of $M_2$ and 3 cycles/month less than that of $S_2$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can resynthesize a time series of tidal elevation &lt;a href=&quot;https://i.stack.imgur.com/BdmxZ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BdmxZ.png&quot; alt=&quot;maximum amplitude of tide&quot;&gt;&lt;/a&gt; based on only these three tidal constituents ($M_2$, $S_2$, and $N_2$). The resulting time series of amplitudes has an envelop that shows the size of the spring tides. As can be seen in the figure, even including only these three constituents, the resulting variability in the size of the spring tides (12 years shown) is pretty high. The problem is how to define &quot;king tides&quot;. There are some spring tides that are larger than others, but even among the largest there is variability. This is where the uncertainty on the definition of the recurrence interval of the &quot;king tides&quot; comes from. Ultimately, it seems that having ~2 peaks (&quot;king tides&quot;) per year is a good approximation. Including 3 constituents is a significant simplification and the entire series gets more complicated when additional constituents are included and defining a &quot;king tide&quot; is also more difficult.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2016-10-26T15:32:17.977" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8960" PostTypeId="2" ParentId="8930" CreationDate="2016-10-26T16:31:53.417" Score="2" Body="&lt;p&gt;Estimates of earth's total biomass vary widely, from 0.5 to 4 trillion tons C, so instead of citing a source, I'll just go with an assumption of $1\times10^{15} \text{kg C}$. Measuring biomass in carbon is a convenient segue to the next assumption: assume that all biomass burns only in $\text{CX + O}_2\,\rightarrow\,\text{CO}_2 + \text{X}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given these assumptions, $1\times10^{15} \text{kg C}\cdot \frac{1 \text{mol C}}{0.012 \text{kg C}} = 8.3 \times10^{16} \text{mol C}$. To react with so many mol's $\text{C}$ we will need the same number of mols of $\text{O}_2$, at molar mass $0.032 \text{kg O}_2$, which gives us a total of $2.7\times10^{15} \text{kg O}_2$ needed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oxygen is 20% of the atmosphere, which means there is $5.1\times10^{18} \text{kg atm} \cdot 0.2 \frac{\text{O}_2}{\text{atm}} = 1.0 \times 10^{18} \text{kg O}_2$ available. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since we have calculated that there are three orders of magnitude as much oxygen available as is needed to burn all biomass, I feel confident saying that &lt;em&gt;global&lt;/em&gt; loss of oxygen due to burning biomass was not a cause of the P-Tr extinction. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also relevant: there is nowhere near a consensus that an asteroid impact caused the P-Tr extinction. To the best of my knowledge, an asteroid strike is not the most popular theory for that specific extinction event. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="6703" LastEditDate="2016-10-26T17:45:18.863" LastActivityDate="2016-10-26T17:45:18.863" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8961" PostTypeId="2" ParentId="8874" CreationDate="2016-10-26T20:19:17.013" Score="2" Body="&lt;p&gt;Latent heat release is critical for the general circulation, in particular the tropical overturning circulation (Hadley &amp;amp; Walker circulations). The release of latent heat is the dominant diabatic heating of the tropical atmosphere, and provides much of the upward mass flux in the deep tropics (the ascending branch of the overturning circulation). In contrast, at higher latitudes the radiative cooling becomes the dominant diabatic term. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is discussed in some of the standard text books. One example is in The Physics of Climate by Peixoto and Oort, in their Chapter 13. Here is a paraphrase of their section 13.3.1:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Diabatic processes are the sources and sinks of internal energy within the atmosphere, so they play a crucial role in many phenomena like convection, fronts, etc. Following Newell et al. (1970), estimates of the zonal average diabatic heating terms are shown in a figure (13.2). The net radiative heating is generally negative, but in parts of the tropical stratosphere it becomes slightly positive because of absorption by ozone. The latent heat release (estimated from precipitation) have three local maxima associated with strong convection in the ITCZ and with the polar fronts in both hemispheres. Boundary layer heating is confined to the lowest levels, as expected. The release of latent heat dominates in the tropics where it leads to net heating. At high latitudes, radiative cooling becomes dominant.&lt;/p&gt;&#xA;" OwnerUserId="3339" LastEditorUserId="3339" LastEditDate="2016-10-27T15:19:05.780" LastActivityDate="2016-10-27T15:19:05.780" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8962" PostTypeId="2" ParentId="8957" CreationDate="2016-10-26T22:21:18.843" Score="4" Body="&lt;p&gt;There is no reason you couldn't have uranium deposits in the continental shelf. Certain types of deposits wouldn't occur or be likely to persist in that environment but other types such as those in Archean metasediments likely could be found.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As pure speculation, I can envision formation of deposits similar to unconformity or roll-front deposits where deep-circulating groundwater discharges through organic-rich ocean sediments. The organic material would cause the uranium to precipitate in a reduced oxidation state. That would likely be up on the shelf so I don't know if you could make it work if you want to be down on the edge of the shelf.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2016-10-26T22:21:18.843" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8963" PostTypeId="2" ParentId="8957" CreationDate="2016-10-27T01:01:28.183" Score="5" Body="&lt;p&gt;There are about 3 tonnes of uranium in every cubic kilometre of seawater, but in the general circulation there is no mechanism to concentrate the uranium, except perhaps low-level adsorption on manganese nodules in some parts of the sea bed. To concentrate the uranium you need some mechanism to transport it, and some other mechanism to make it precipitate. Both are pH-redox controlled, requiring substantial reducing conditions. The nearest plausible mechanism I can think of is a high concentration of uranium in groundwater, such as in the Aktau province of Kazakhstan, adjacent to the Caspian Sea. At present the Caspian is too oxygenated, and is likely to remain that way because of inflow from the Volga, but if climate change alters the rainfall-runoff relationship then that inflow to the Caspian would be reduced. Conceivably, it wouldn't take too much more pollution and reduced river inflow to make the deeper parts of the northern Caspian more reducing. Then maybe you could get uranium deposition at the groundwater-lakewater interface. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2016-10-27T06:44:43.353" LastActivityDate="2016-10-27T06:44:43.353" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8964" PostTypeId="2" ParentId="8946" CreationDate="2016-10-27T02:45:27.540" Score="1" Body="&lt;p&gt;Other ways that animals can affect soils is by burrowing, overturning soil through digging or ploughing and also through shallow diggings/scrapings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Burrows create voids/chambers in soils that can allow air to react with soil beneath the land surface. Likewise they provide easier pathways for water to penetrate soil and affect changes that way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Overturning soil whether its due to animals looking for food or human agriculture buries soil that was on the surface and brings deeper soil to the surface. It also aerates the top portion of the soil and it allows for easier penetration by water and it provides a greater surface area of soil to be exposed to the air in the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shallow digging or scrapings by animals, particularly in very hard capped soils can create broken patches that allow water to penetrate a hard impervious cap and allow the water to penetrate deeper in the soil than it would otherwise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, once soil has been overturned and aerated, whether by animals or humans, wind can blow away parts of the soil.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2016-10-27T02:53:36.747" LastActivityDate="2016-10-27T02:53:36.747" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8965" PostTypeId="2" ParentId="8958" CreationDate="2016-10-27T07:26:08.767" Score="2" Body="&lt;p&gt;This is arguably a theological rather than science-based issue, but since it is cross-cutting I will answer it. No, there is no possible mechanism for the sun to cease shining for three hours, but neither is there any such imperative implied in the original Greek text, which requires only a &lt;em&gt;relative&lt;/em&gt; darkening of the sun. You are correct is recognizing that this was no eclipse. It may be noted that comparable 'darkness' is implied in other Biblical accounts, such as in Exodus, Joshua and Amos. Nowhere in these four texts is &lt;em&gt;total darkness&lt;/em&gt; either stated or implied, but naturalistic explanations (i.e. scientific) - which in no way detract from the spiritual intent of the text - may be eminently applied to correct textural understanding.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As in so many modern misunderstandings, the apparent conflict between science and Biblical theology entirely disappears when the Bible is read sensibly from the appropriate perspective. The Bible is not a modern Greco-Roman literalist quasi-scientific text, and it is absurd to treat it as such. the Bible is basically a spiritually-inspired collection of 2000 to 3000 year-old Hebrew texts, written in the parabolic allegory-rich idiom of ancient Jewish culture. For all that, it is no less accurate in spiritual wisdom - but radically different from the 21st century world views. &#xA;Not only is it literature from a different culture, we also don't have any of the original texts! You are arguing on the basis of a modern British translation of a Greek translation of presumed Aramaic literature, which itself may have undergone several cycles of editing (as in the Noah story, which has at least four cycles of precursor literature).  Subtleties of meaning are lost in each stage of translation, so before drawing over-literal assumptions, first at least check the nuances of the earliest Greek translation. Had you done that, the question of absolute darkness would not have arisen, and partial darkness would more than adequately have proved correct - such as a sandstorm (as 'A child of God' suggested) or a super-cell storm cloud - which does occasionally occur in the Israeli highlands. Such superstorm events may indeed &lt;em&gt;seem&lt;/em&gt; to be like night if they occur only minutes after the intense bright Mediterranean sunlight of the Jerusalem highlands.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many Christians get hot under the collar when scientific explanations are applied to miracles such as this. It need not be so. It is not a case of &quot;look at God doing the impossible, again&quot;, but of placing due emphasis upon the true miracle, which is the exquisite timing of the event in support of God's unfolding plan.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-10-27T07:26:08.767" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8970" PostTypeId="1" AcceptedAnswerId="8972" CreationDate="2016-10-27T15:19:32.060" Score="5" ViewCount="270" Body="&lt;p&gt;I am researching the abundances of rare earth elements and &lt;a href=&quot;http://web.mit.edu/12.000/www/m2016/finalwebsite/elements/raremetals.html&quot;&gt;rare metals&lt;/a&gt; in meteorite samples, because I want to investigate the notion that asteroids represent abundant stocks of rare resources. The literature on space resources speaks volumes about platinum group metals, but little about anything else, so I did my own homework. Unfortunately I have no background in mineralogy, and I cannot find data on the actual abundances (in ppm, percent, or micrograms/gram and so on) of REEs/rare metals in meteorite samples. I figure this is an appropriate place for this question, sorry if I'm wrong.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My understanding is that the abundances of non-volatile elements in CI chondrites represents the primordial abundances at the formation of the Solar system. Therefore, the REE+rare metal content of other types of meteorite, and thus asteroid rock, is generally given by comparison to the CI chondrites -- ie, how much more or less enriched they are.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem for me is that the CI abundances seem to be nowhere specified in ppm or any measure relevant to mining, so I have no idea how useful any of these rocks could be for evaluating asteroid ore viability. The literature on economically viable ore grades seems to specify quantities of rare elements between 0.1% and 10% per unit mass, for commercial mining. So what are the abundances of rare elements in different meteorite types in ppm/percent?&lt;/p&gt;&#xA;" OwnerUserId="6859" LastActivityDate="2016-10-27T16:48:15.613" Title="What is the CI chondrite concentration of REEs/rare metals, in ppm/grams per ton?" Tags="|geology|geochemistry|planetary-science|mineralogy|mining|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8971" PostTypeId="2" ParentId="8970" CreationDate="2016-10-27T16:07:41.723" Score="2" Body="&lt;p&gt;Table 2 of this &lt;a href=&quot;https://arxiv.org/pdf/1010.2746.pdf&quot; rel=&quot;nofollow&quot;&gt;paper&lt;/a&gt; lists concentrations in CI chondrites of all elements in ppm with variances. This is for one 14kg meteorite that fell in Orgeuil, France in 1868.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Check out pages 8-10 for the table and data.&lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-10-27T16:07:41.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8972" PostTypeId="2" ParentId="8970" CreationDate="2016-10-27T16:48:15.613" Score="3" Body="&lt;p&gt;You should start with the &lt;a href=&quot;https://earthref.org/GERMRD/datamodel/&quot; rel=&quot;nofollow noreferrer&quot;&gt;GERM Reservoir Database&lt;/a&gt;. Not the easiest to use website, but the most comprehensive. You can look up elemental concentrations in all kinds of &quot;reservoirs&quot;, including meteorites. For example, look up &lt;a href=&quot;http://earthref.org/GERMRD/49/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CI Chondrites&lt;/a&gt; to see the elemental values that are commonly used for REE-diagram normalisation. You can look up by specific meteorites, or averages of groups. You can see values by paper, and in most cases they also include a scan of the original data from the paper itself. Note that it's also usually good practice to actually read the paper to understand how the data were collected, analysed and what do they mean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, as for your general idea of using asteroids as ore deposits for rare metals:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...because I want to investigate the notion that asteroids represent abundant stocks of rare resources.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As a rule of thumb, this works well for the PGE (platinum group elements) and related metals (Te, Au, Re). The reason is that those metals are chalcophile or siderophile, and in the Earth they are concentrated in the core and depleted in the mantle and crust. In (some) asteroids, this differentiation did not occur and the concentration of these elements is still (relatively) high in the bulk material.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the REE and other HFSE metals (i.e. Zr, Hf, Nb, Ta), are not concentrated in the core. In fact, being lithophile elements, they are particularly enriched in the Earth's crust. Going to mine them from asteroids will be pointless.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are some more questions and answers that will clarify some concepts:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/8214/725&quot;&gt;Why is uranium only in the crust, really?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/8170/725&quot;&gt;What is the difference between chalcophile and siderophile elements?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/2950/725&quot;&gt;What are the high field strength and large ion lithophile (HFS or HFSE &amp;amp; LIL or LILE) elements?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-10-27T16:48:15.613" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8973" PostTypeId="1" CreationDate="2016-10-27T17:19:38.773" Score="3" ViewCount="686" Body="&lt;p&gt;The Himalayas are rising--as many people have heard. What other mountain ranges are still rising at a rate faster than they are being worn down by erosion?&lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-10-27T19:12:19.843" Title="Which mountains are rising?" Tags="|geology|mountains|mountain-building|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8974" PostTypeId="2" ParentId="8973" CreationDate="2016-10-27T17:42:40.463" Score="3" Body="&lt;p&gt;Anywhere on the planet where there is plate convergence probably has rising mountains, even in the ocean where there is back-arc volcanism, although the mountain building may be out of sight from the sea floor. So that includes all of the Andes, much of the European Alps, New Guinea and Indonesia. But there is not much happening in Africa or Australia. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-10-27T17:42:40.463" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8977" PostTypeId="1" CreationDate="2016-10-28T05:27:57.283" Score="-2" ViewCount="97" Body="&lt;p&gt;Why is it that gems/ rocks, such as Ruby, Sapphire, Topaz, etc... all have their own unique colors? Is this something that happens from chemical attraction with each stone upon formation? &lt;/p&gt;&#xA;" OwnerUserId="6867" LastActivityDate="2016-10-28T07:13:18.150" Title="Color in Gems and Rocks" Tags="|rocks|" AnswerCount="1" CommentCount="1" ClosedDate="2016-10-28T14:43:26.733" ContentLicense="CC BY-SA 3.0" />
  <row Id="8978" PostTypeId="2" ParentId="8977" CreationDate="2016-10-28T07:13:18.150" Score="1" Body="&lt;p&gt;There is no simple answer to this. The colour can be caused by trace or minor elements in the gemstone. Cr, Ti, Mn, Fe, Co, Cu and a few other metals have a strong colour control, as does their oxidation state. eg. Chrome and titaniaum gives the colour of ruby, iron gives the colour of olivine. Another effect is disruption of the crystal lattice, e.g. by heat, internal radiation, artificial radiation or physical shock. Then there is the intrinsic molecular structure of the mineral itself, as in moonstone. Schiller effect, and similar arrays of colour can be caused by optical interference between micocrystalline twins or microscopic intergrowths of two similar minerals, as in various varieties of feldspar. Other effects are pleochroism (Alexandrite), trichroism (Tanzanite), Chattoyance (Tourmaline), and microscopic inclusions (various forms of silica).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is quite a big subject, but there are many good well-illustrated texts to read more. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-10-28T07:13:18.150" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8979" PostTypeId="2" ParentId="5321" CreationDate="2016-10-28T13:29:03.033" Score="15" Body="&lt;p&gt;First off, your observation that Tamil Nadu gets more rainfall in the evening is partially backed by records. &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2009JD012644/full#jgrd15857-bib-0003&quot; rel=&quot;noreferrer&quot;&gt;Sahany, Venugopal, and Nanjundiah, 2010&lt;/a&gt; provide data on diurnal scale rainfall distribution during the Southwest monsoon season shows that Tamil Nadu is dry from 0530-1430 each day, and likely to be wet from 1730-0230:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FNn6n.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FNn6n.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Northeast monsoon is different. From &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/met.1322/full&quot; rel=&quot;noreferrer&quot;&gt;Rajeevan et al, 2012&lt;/a&gt; the NEMR (North East Monsoon Rainfall) peaks in the evening for most of Tamil Nadu but the coast facing the Bay of Bengal (including Chennai) peaks in early morning (0330-0630):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/S02ms.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/S02ms.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding the reasons for this, here are some excerpts from &lt;a href=&quot;http://journals.ametsoc.org/doi/full/10.1175/MWR3355.1&quot; rel=&quot;noreferrer&quot;&gt;Basu, 2007&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In the Tropics most of the rainfall is from the tall clouds (Cu or Cb)&#xA;  formed by convection within a deep layer of the atmosphere. The usual&#xA;  forcing for such clouds to form is the heating from below by the solar&#xA;  radiation absorbed by the ground during the day. This forcing is&#xA;  maximum near the time of maximum surface temperature and the first of&#xA;  the thunderstorms caused by insolation start near 1430 local time&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Over the sea areas along the east coast (south of 15°N) too, the&#xA;  maximum in precipitation occurs in the early morning hours as the&#xA;  synoptic-scale westerly is weak over this region and the diurnal&#xA;  variation is dominated by the land–sea breeze.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Also worth noting, from &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/joc.1458/pdf&quot; rel=&quot;noreferrer&quot;&gt;Roy and Balling, 2007&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The strength  of  the  diurnal  cycle  is  greatest  in  the &#xA;  peninsular region with close to 96% variance explained for stations&#xA;  located in Tamil Nadu.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My interpretation of this is that inland Tamil Nadu sees high surface temperatures from sunlight through clear skies striking the ground. The resulting heat is released in the late afternoon and evening, which causes cumulus or cumulonimbus cloud formation and rainfall. During this, the ground cools off at a rate faster than the nearby Bay of Bengal. This causes oncoming sea breezes laden with moisture and coastal rainfall peaks in the early morning hours. In Tamil Nadu especially, this pattern is very stable.&lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-10-28T13:29:03.033" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8985" PostTypeId="1" AcceptedAnswerId="8991" CreationDate="2016-10-29T18:51:02.570" Score="1" ViewCount="188" Body="&lt;p&gt;I'm reading the sci-fi novel &lt;em&gt;Saint Leibowitz and the Wild Horse Woman&lt;/em&gt;, and in the story a pope in the post-apocalyptic future moves the prime meridian from England to the U.S. It is an unpopular decision, because according to the author not only would it confuse navigation, but it would decrease the amount of time until it is necessary to drop a day to keep in line with planetary movement. I'm trying to understand the logic of this, but I don't get at all why this would happen.&lt;/p&gt;&#xA;" OwnerUserId="6877" LastEditorUserId="6877" LastEditDate="2016-11-14T15:03:16.840" LastActivityDate="2016-11-14T15:03:16.840" Title="Why would moving the prime meridian hasten the time when it would be necessary to drop a day from the calendar?" Tags="|geography|hypothetical|time|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="8988" PostTypeId="2" ParentId="8985" CreationDate="2016-10-30T10:41:32.510" Score="2" Body="&lt;p&gt;There is no basis in logic to have to subtract a day due to a change in the prime meridian.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both the Julian &amp;amp; Gregorian calendars require days to be added, not subtracted. It's why we have leap years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, both the Julian &amp;amp; Gregorian calendars were established centuries before the prime meridian was set in the 19th century. The formula for adding days &amp;amp; creating leap years was set long before the prime meridian was even contemplated.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-10-30T10:41:32.510" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="8989" PostTypeId="2" ParentId="8985" CreationDate="2016-10-31T02:44:09.297" Score="1" Body="&lt;p&gt;To give a fuller explanation, the current calendar is the Gregorian calendar, which was introduced in 1582 to address the inaccuracies of the older Julian calendar. The Julian calendar gains a day every 128 years because the year is 365 with a leap day every 4 years for an average of 365.25 days long (the actual year is 365.24217 mean solar days). By the time of pope Gregory, the one day every 128 years translated into a 13 day discrepancy between the calendar ad the seasonal cycle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Gregorian calendar drops the leap year every 100 years (but keeps it every 400 years) for an average of 265.2425 days per year, so it gains a day only every 3030 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, changing the number of days before you need to 'drop' a day to keep the calendar in place is done by adding or removing leap days. The Prime meridian has nothing to do with that. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="6703" LastEditDate="2016-10-31T02:59:49.580" LastActivityDate="2016-10-31T02:59:49.580" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8990" PostTypeId="1" CreationDate="2016-10-31T03:20:45.257" Score="2" ViewCount="121" Body="&lt;p&gt;So I am a science nerd. I am literally the guy in high school who would run up to people and say &quot;hey, I just learned quartz is formed from rapidly cooling magma. Isn't that awesome!&quot; I'm actually currently working towards a high school biology degree but when I'm done with that I will continue with an earth science degree until I can teach college. Not just a dream, I WILL make it happen. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyway, I was wondering what sorts of tricks I can do right now to play with geology until I actually can get into the field. Like is it possible to analyze the composition of my own backyard using basic tools? I have the gusto, I literally just launched some R-candy rockets using a mix of 63% KNO3, 32% sucrose, 4% aluminium and 1% iron sulfate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, is there any self employment for amateur geologist? Like if I figure out how to analyze my own yard, can I then do the same for others for a small fee? (I'm a substitute teacher now so I'm always broke).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;What cool things can be done by an amateur geologist with no prior geological schooling (and very limited funding) but with a strong drive to understand the world we live in?&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS. I built a primitive forge from homemade clay bricks that I use to melt aluminum from scrap into art so is there any uses for that in amateur geology?&lt;/p&gt;&#xA;" OwnerUserId="6885" LastEditorUserId="595" LastEditDate="2016-10-31T08:50:05.260" LastActivityDate="2016-10-31T08:50:05.260" Title="Future geology professor wants to know quick fixes to get me through unstimulating period" Tags="|geology|teaching|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8991" PostTypeId="2" ParentId="8985" CreationDate="2016-10-31T04:01:36.580" Score="1" Body="&lt;p&gt;I don't know the book and the quality of fiction are rarely in the facts. However, it is always nice to think about the spinning of our planet and how our theories and methods relate to the actual astronomic observations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Historically there have been a number of &lt;a href=&quot;https://en.wikipedia.org/wiki/Prime_meridian#List_of_prime_meridians_on_Earth&quot; rel=&quot;nofollow&quot;&gt;prime meridians&lt;/a&gt;, sometimes used simultaneously and sometimes to &lt;a href=&quot;http://www.objectifterre.org/tintin/images/planche-meridien-paris.jpg&quot; rel=&quot;nofollow&quot;&gt;large confusion&lt;/a&gt;. However, what reference you use doesn't change the duration of day and year. The calendars clearly described by Fred and kingledion are there to synchronize the day of year with the astronomic reasons for seasons. Farmers as well as priests plan the year according to the calendar dates and expect &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/e/e1/Hours_of_daylight_vs_latitude_vs_day_of_year_cmglee.svg&quot; rel=&quot;nofollow&quot;&gt;equinox&lt;/a&gt; at same day every year and the harvest to be in the same month. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can think of the prime meridian as the offset and the calendar as the frequency of our time units. Even when we refer the &lt;a href=&quot;http://www.worldtimeserver.com/current_time_in_UTC.aspx&quot; rel=&quot;nofollow&quot;&gt;time zone to Greenwich&lt;/a&gt; it is still only a way to express the relation between time zones. With a &lt;a href=&quot;https://en.wikipedia.org/wiki/Washington_meridians#New_Naval_Observatory_meridian&quot; rel=&quot;nofollow&quot;&gt;US prime meridian&lt;/a&gt; the sun would still rise about 6am at equinox all over the world unless the evil pope in the book also forced a time zone of choice to people living near other meridians. However there might be situations where it's &lt;a href=&quot;https://en.wikipedia.org/wiki/Time_in_Russia#Railway_time&quot; rel=&quot;nofollow&quot;&gt;practical&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Time_in_China&quot; rel=&quot;nofollow&quot;&gt;politically motivated&lt;/a&gt; to use the same time across meridians, even if it means that some people will have sunrise well into lunch time at equinox. Technically, by moving the prime meridian some 30° to the west while keeping the Gregorian calendar would only delay the &lt;a href=&quot;https://en.wikipedia.org/wiki/Gregorian_calendar#/media/File:Gregoriancalendarleap_solstice.svg&quot; rel=&quot;nofollow&quot;&gt;correction dates&lt;/a&gt; with a few hours, but on the other hand, people living just East of the &lt;a href=&quot;https://en.wikipedia.org/wiki/International_Date_Line&quot; rel=&quot;nofollow&quot;&gt;International Date Line&lt;/a&gt; will get their correction a day earlier, and might appreciate the new cardinal coordinates, if they have an extremely strong sense for daylight and time. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Gregorian calendar was an important step to adjust the supernatural believes to actual observations. A year that is 365.2425 days long suggests a more complex universe than any simple cogwheel mechanics. If the evil pope really would like to suppress logic and perception, he or she should change the length of our time units rather than just relocating the coordinate system. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2016-10-31T04:13:36.377" LastActivityDate="2016-10-31T04:13:36.377" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8992" PostTypeId="2" ParentId="8990" CreationDate="2016-10-31T04:29:11.207" Score="6" Body="&lt;p&gt;I'd suggest to get out and do some mapping. Get a map, look for local outcrops and mark them on your map. Try to find the same type of rocks or unit in more than one location and try to connect them. Compare it with published maps and see if it makes sense. Then start to think about the reasons why the units are located as they are and read a bit about tectonics. Your chemical interest is useful to define the rocks you find (e.g. use acid to recognize carbonates) and your biological interest is useful if you are fortunate enough to live in an area where you can find fossil bearing rocks to help you with the dating. The experiences you make whiles learning the trade can suggest what the local work market looks like. Learn &lt;a href=&quot;http://www.qgis.org/en/site/&quot; rel=&quot;noreferrer&quot;&gt;GIS&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Geologic_map&quot; rel=&quot;noreferrer&quot;&gt;mapping&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geology is a great way to combine theoretical studies with fieldwork and use some excess energy. Let your interests define what branch of geology you would like to focus on. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LiqOk.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LiqOk.jpg&quot; alt=&quot;From reddit&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are looking for professional projects, I'd contact local engineering companies that work with infrastructure or similar and check if the need extra crew for fieldwork. There are sometimes casual workers needed for geophysical surveying or sampling. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Depending on where you live, groundwater could be another option, contact local drilling companies, learn how to handle a rig and learn some hydro-geology. With a detailed geological map of an area, groundwater modellers can make better decisions - maybe even paying something for the data. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2016-10-31T04:47:21.210" LastActivityDate="2016-10-31T04:47:21.210" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="8993" PostTypeId="2" ParentId="8890" CreationDate="2016-10-31T04:44:37.327" Score="0" Body="&lt;p&gt;I actually disagree that pressure isn't a significant factor. It is pressure and temperature together that determine boiling and condensation points. The atmospheric pressure on Everest is roughly 1/3 that of standard atmospheric pressure making water boil at 71C instead of at 100C. Using simple plastic containers like 2 liter bottles you can achieve around 100 psi safely which is roughly 7 times standard atm. For this reason you can create a cloud in plastic bottles using a bike pump or even just squeezing it to manipulate this principle. This link shows you how to make a cloud in a bottle with actual water &lt;a href=&quot;http://www.wikihow.com/Make-a-Cloud-in-a-Bottle&quot; rel=&quot;nofollow&quot;&gt;http://www.wikihow.com/Make-a-Cloud-in-a-Bottle&lt;/a&gt; but if you want some wow factor you can use a bike pump and alcohol to form a large amount of fog or cloud like in this link &lt;a href=&quot;http://www.abc.net.au/science/articles/2013/05/21/3759793.htm&quot; rel=&quot;nofollow&quot;&gt;http://www.abc.net.au/science/articles/2013/05/21/3759793.htm&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6885" LastActivityDate="2016-10-31T04:44:37.327" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8994" PostTypeId="2" ParentId="1046" CreationDate="2016-10-31T16:41:28.500" Score="1" Body="&lt;p&gt;The 1967 International Biological Programme has a handbook of suggestions for various methods to calculate &lt;a href=&quot;http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.475.3375&amp;amp;rep=rep1&amp;amp;type=pdf&quot; rel=&quot;nofollow&quot;&gt;primary productivity of forests&lt;/a&gt;. A subset of these measures would be effective for measuring litter production.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding leaves and other falling litter, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Bags suspended from hoops (Ovington &amp;amp; Murray 1964) about 1 m above the&#xA;  soil. The hoops would be at least 0.5 m in diameter. The bag should be&#xA;  freely permeable to water (nylon mesh, cheese cloth, sail cloth, etc.)&#xA;  to reduce moisture and decomposition inside the bag. Care must be&#xA;  taken with this type of litter trap that the hoop does not incline out&#xA;  of the horizontal and the bag must be pegged or weighted to prevent it&#xA;  blowing inside out.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Further, the handbook suggests no less than 20 leaf traps in one sample area, and checking contents every week especially in moist areas. Also, to account for branch fall, the weekly collection should check for and weigh fallen branches in a 20m X 20m area. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For fine roots:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;An additional estimate of fine roots can be obtained either by&#xA;  excavation of soil monoliths, or by taking soil cores (e.g. Bray,&#xA;  Lawrence &amp;amp; Pearson 1959) down to a depth of at least 50 cm and washing&#xA;  out the fine roots over a sieve. So far as is possible only live roots&#xA;  should be included.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;For ground cover:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Where distinct plants of a single or only a few species are present,&#xA;  the best procedure will be to collect a number of individual plants of&#xA;  each species (preferably including subterranean organs) at monthly&#xA;  intervals through the year. The collected plants are separated into&#xA;  leaves, flowers, stems and roots, which are dried and weighed. These&#xA;  individual plant data can then be combined with density (number of&#xA;  individual plants/area) data for conversion to an area basis. The sum&#xA;  of (Species A max. biomass - min. biomass) + (Species B max. biomass min. &#xA;  biomass) ... gives an estimate of net production.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I believe that should account for the significant components of litter production. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-10-31T16:41:28.500" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8995" PostTypeId="2" ParentId="24" CreationDate="2016-10-31T17:33:26.800" Score="6" Body="&lt;p&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469%281979%29036%3C0415%3AALRRAT%3E2.0.CO%3B2&quot; rel=&quot;noreferrer&quot;&gt;Stone and Carlson, 1978&lt;/a&gt; suggest that lapse rate is dependent on latitude (i.e. incidence angle and intensity of sunlight) and pressure rather than temperature. It is the sunlight pattern which drives the circulation patterns that are the dominant effect of air temperature with altitude: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In low latitudes where moist convection dominates, the lapse rate agrees &#xA;  closely with the moist adiabatic lapse rate; and in high latitudes where &#xA;  baroclinic eddies dominate, the lapse rate agrees closely with the &#xA;  critical lapse rate for baroclinic adjustment. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The latitude determines daily changes in temperature due to solar energy. This leads me to believe that changes in average temperature (due to climate change) will not affect lapse rate so much as solar incidence due to latitude (which will not change with global warming). However, there remains the potential effect of increased humidity caused by increased temperatures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An analysis of lapse rate measurements over broken terrain in Washington state (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2009JD013493/full&quot; rel=&quot;noreferrer&quot;&gt;Minder, Mote, Lundquist, 2010&lt;/a&gt;) shows the differences between wetter and dryer conditions on the windward and leeward sides of Mt. Ranier. A calculation of lapse rate up the mountain by season yields this chart:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JJoJM.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JJoJM.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are three distinct data sets: the solid black is the same on both a. and b. and is the measurements in 2006-2007 of lapse rate by month. The grey with circles data set from a. and grey with triangles from b. are two historical data sets from different sources. The dashed lines in each data set are on the leeward (dry) side of the mountain, the solid lies on the windward (wet).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, the seasonal variance is present in all three datasets; as the sun comes more nearly overhead in the summer lapse rate goes up. Also notice that for the leeward data, the lapse rate peaks in Jun, when the sun is highest in the sky, as opposed to July and August, when temperatures are high. That reinforces the thesis that sun angle is dominant over temperature. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the other bit of relevant data is that the wet side of the mountains has significantly less annual variability in lapse rate than the dry side. This implies that humidity changes due to global warming will indeed cause changes in lapse rate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In conclusion, I believe that temperature changes due to climate change will not significantly alter lapse rate; but humidity changes will. However, since humidity changes due to climate change are likely to be much more local and variable than the more globally even increases in temperature, lapse rate changes should be local and variable as well. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to answer the question directly, the '3D' changes in lapse rate will probably not be significant, in that there will not be a clear global trend across all latitudes, longitudes, and altitudes. However, local changes may be significant depending on local humidity changes. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-10-31T17:33:26.800" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="8996" PostTypeId="1" CreationDate="2016-11-01T06:59:51.707" Score="4" ViewCount="1560" Body="&lt;p&gt;I am reading about the Samoan tsunami of 2009, in which several independent accounts by survivors said that the wave was 'hot'. They were running for their lives at the time, so were very remiss in failing to actually measure the water temperature. I'm leaning towards the explanation that the water &lt;em&gt;seemed&lt;/em&gt; hot because of the adrenaline rush, but before jumping to conclusions, I'm also wondering if (a) there is any other record of a tsunami wave being hot, and (b) could the dissipation of kinetic energy be sufficient to raise the temperature by several degrees? FYI the earthquake that caused the tsunami was a magnitude 7.9, at shallow depth in the Tonga Trench subduction zone, about 300 km away. The wave was up to 16 metres high.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2016-11-01T07:07:58.467" LastActivityDate="2016-11-01T19:10:16.263" Title="How can a tsunami be 'hot'?" Tags="|tsunami|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="8997" PostTypeId="1" CreationDate="2016-11-01T12:24:51.657" Score="5" ViewCount="4935" Body="&lt;p&gt;When looking at a map of Europe, I always wonder why the North-West coast of Scotland has a very similar craggy outline to the NW coast of Norway. It is completely different to the smooth outline of the Eastern coast:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6sXJ6.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6sXJ6.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my question is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the geological reasons for the distinctive outline of Scotland's North-West coast?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hopefully a full explanation would include answers to the following questions:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Why are they the same in Norway? (were they once joined together?)&lt;/li&gt;&#xA;&lt;li&gt;Why are they so different on the Eastern coast?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="6776" LastActivityDate="2016-11-02T07:35:39.520" Title="Why does NW coast of Scotland look like it does? (Similar to Norway, so different to other European coastlines)" Tags="|geology|geography|coastal|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8998" PostTypeId="2" ParentId="8997" CreationDate="2016-11-01T14:03:39.990" Score="6" Body="&lt;p&gt;These are actually a geological feature called &quot;fjord&quot; which the Scandinavian Peninsula and surroundings (including Scotland) are known for. It is the result of glacial erosion during the Ice Ages. See more info here: &lt;a href=&quot;https://en.wikipedia.org/wiki/Fjord&quot; rel=&quot;noreferrer&quot;&gt;Fjord (Wikipedia).&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5077" LastEditorUserId="6093" LastEditDate="2016-11-02T07:35:39.520" LastActivityDate="2016-11-02T07:35:39.520" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="8999" PostTypeId="2" ParentId="8996" CreationDate="2016-11-01T19:10:16.263" Score="4" Body="&lt;p&gt;I can't answer part a, but I can help with part b. We first must determine how much kinetic energy, then we can use simple thermodynamics to see how much that could possibly heat up a mass of water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kinetic energy calculations are numerically modeled in &lt;a href=&quot;http://rspa.royalsocietypublishing.org/content/465/2103/725.short&quot; rel=&quot;noreferrer&quot;&gt;Dutykh and Dias, 2009&lt;/a&gt;. Their largest example uses parameters of a 150km x 50km x 35km fault slipping by 15m at 4 km depth (values in Table 2 of paper). Total energy computed is shown in the graphs below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aDUY2.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aDUY2.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Part a. of the table is kinetic energy, and part b. is potential energy. For the earthquake with parameters in Table 2, released kinetic energy is about $3\times10^{14}\text{ J}$, with about the same going into potential energy of the wave. I couldn't find any reliable sources of equating energy release with earthquake magnitude, but according to &lt;a href=&quot;https://en.wikipedia.org/wiki/Richter_magnitude_scale#Energy_release_equivalents&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;, $3\times10^{14}\text{ J}$ is equivalent to about a 6.6 earthquake. Take that for what its worth, I was just trying to get a sense of how powerful the earthquake causing the tsunami in question would be.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From here lets see what happens if all that energy (kinetic and potential) is converted to thermal energy. To warm up water noticably, lets say we want a $5\unicode{x2103}$ increase. The specific heat of seawater is $3985 \frac{\text{J}}{\text{kg}\cdot\text{C}}$, and the density is $1025\frac{\text{kg}}{\text{m}^3}$. Therefore the energy released from this tsunami can heat up $$ \frac{6\times10^{14}\text{ J}\cdot 5\unicode{x2103}}{3985 \frac{\text{J}}{\text{kg}\cdot\text{C}}} = 7.5\times10^{11} \text{kg of water} \cdot \frac{1}{1025\frac{\text{kg}}{\text{m}^3}} = 7.3 \times10^{8} \text{m}^3 $$ of water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The last question is: is this enough? Well, sort of. Since the energy is radiated in all directions, at a distance of 200 km, the tsunami wavefront has a circumference of $2\cdot \pi\cdot200 = 1257 \text{km}$ so each meter of wavefront corresponds to 580 m$^3$ of heated water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This operates under the assumption that all energy is converted to heat, and that all the tsunami's heat is concentrated in one 580 m$^3$ water slug for ever meter of wavefront at 200 km away. While these assumptions are not perfect, I think a lot depends on the way the wave breaks. If it breaks suddenly (i.e. a suddenly rise from deep water to shallow), you might see a more concentrated conversion of kinetic energy to heat. And 580 m$^3$ is a pretty big mass of water; that would correspond to the heated section of the wavefront being an expanding ring 100m wide and 5.8m deep at 200km distance. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what I conclude from this thought experiment is that it is plausible that a tsunami from a mid-size earthquake could cause the water hitting the beach to heat up several degrees, given that the wave doesn't travel too far, and that it breaks in the right way (whatever that right way is). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding Samoa, the earthquake at 7.9 put out more energy than we are dealing with here, and Samoa is about 200km from the Tonga trench (though I don't know where in the trench the quake actually took place), so I'll file the hot tsunami theory under &lt;strong&gt;plausible&lt;/strong&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-11-01T19:10:16.263" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9000" PostTypeId="2" ParentId="8997" CreationDate="2016-11-01T19:29:34.763" Score="5" Body="&lt;p&gt;The Northwest of Scotland has a common linkage to Norway in that both are the remains of the once-mightly Caledonide chain of mountains. This was before the Atlantic Ocean opened up, so other fragments of the Caledonides are to be found in Greenland and Eastern North America. See for example the diagrams found in Haakon's website:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://folk.uib.no/nglhe/caledonides.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://folk.uib.no/nglhe/caledonides.html&lt;/a&gt;&lt;br&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/iMAWc.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iMAWc.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/lRYyT.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lRYyT.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Caledonides have a long and complex history, far too long to summarize here. Also, there has been &quot;a lot of geology&quot; since then, so not all of Scotland looks like all of Norway. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another curious point to note is that the extreme northwest of Scotland has Cambrian fossils which are nothing like any you will see in the rest of Europe. They are in fact akin to North American fossils. They were an accidental 'left behind' when the Atlantic started spreading. That is when Scotland and Newfoundland were close neighbours. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, as TonyC points out, both Norway and Scotland (and in fact all of NW Europe, have also been sculpted by the very recent (in geological terms) glaciation.  &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-11-01T19:29:34.763" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9001" PostTypeId="2" ParentId="5398" CreationDate="2016-11-01T19:39:58.717" Score="2" Body="&lt;p&gt;I feel bad answering this one without any research reference, but I can tell you that what you are seeing in the OP's picture is a 'man overboard drill.' In that drill, the objective is to rotate the ship's rear section away from a man who many have fallen overboard and then circle the ship around (in an exact circle) to come up alongside the fallen man. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to do this with a ship, you throw the rudder over hard and fire up the engines ahead full. With many warships, the engine's toque is enough to produce massive cavitation (bubble formation) for the duration of the turn. As you end the turn you will usually throw a 2/3 backing bell, which will produce even more cavitation. That is the 'trail' you see behind the ship. &#xA;Specifically, the ship you see there is &lt;em&gt;HMS Echo&lt;/em&gt;, which has a diesel-electric azimuth drive mounted below the ship, which will provide a very high torque. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lots of cavitation (and you can feel a 10,000 ton ship vibrate during these maneuvers) means lots of bubbles are formed up to 15m below the surface (depending on the size of the ship; only about 6m for the pictured &lt;em&gt;Echo&lt;/em&gt;). As the bubble propagate to the surface they disrupt the passage of surface wavelets and form the calm area shown.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One more factor is that navies train to put the man on the leeward side of the ship during recovery. Thus, in this picture the stern was swung to port (as we can see from the 'trail') so the man must have been on starboard, so the man is on the 'starboard' side of the ship during this recovery. That means the wind should be on the port side, so the calm area is being protected from the wind by the mass of the ship. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-11-01T19:39:58.717" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9002" PostTypeId="1" CreationDate="2016-11-01T20:06:57.913" Score="6" ViewCount="1258" Body="&lt;p&gt;Bowen ratio (BR) is the ratio of sensible heat flux to latent heat flux, i.e., &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$Q=Q_{s}/Q_{l}$$&#xA;where $Q_{s}$ is the sensible heat flux and $Q_{l}$ is the latent heat flux. It is an indicator of the amount of heat lost from the surface to the atmosphere. In water bodies, latent heat of vaporization is higher and hence the bowen ratio is less than one. In dry urban surfaces (e.g., buildings and asphalt roads), evaporation is lower and the bowen ratio is greater than one. &#xA;The bowen ratio over different surfaces have different values. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can we then identify the underlying surface roughness type based on the bowen ratio alone? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am thinking of the latitudinal and altitudinal dependence of the heat flux regime. For example, assume that there are the same vegetation distribution at 1km above sea level (a.s.l) and 4 km a.s.l at different but relatively closer latitudes, then can they have the same bowen ratio? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My idea is that BR is not the right way of quantifying the type of surface roughness because the lower pressure and temperature at 4 km in the example above favors more sensible heat flux than latent heat flux which increases the bowen ratio and gives wrong signal that the surface type is bare soil or sand.&#xA;Can someone explain why BR is used as a means of quantifying the surface roughness type? &lt;/p&gt;&#xA;" OwnerUserId="4877" LastEditorUserId="11908" LastEditDate="2018-03-19T01:16:32.620" LastActivityDate="2018-07-17T03:44:35.517" Title="Is Bowen ratio an absolute indicator of land surface type based on the amount of heat transfer from the surface?" Tags="|land|energy-balance|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9003" PostTypeId="1" AcceptedAnswerId="9023" CreationDate="2016-11-02T02:46:36.540" Score="8" ViewCount="1565" Body="&lt;p&gt;In &lt;a href=&quot;http://www.popsci.com/researchers-find-just-how-much-plastic-were-putting-ocean&quot; rel=&quot;noreferrer&quot;&gt;this article&lt;/a&gt;, they mention that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;More than 4.8 million metric tons [of] plastic waste gets dumped into the world’s oceans from land each year. And this number is just a conservative estimate. Researchers believe the real amount could be as high as 12.7 million metric tons.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;How much total garbage is going into the Pacific Ocean every year? and what fraction of the garbage is &quot;biodegradable&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this other &lt;a href=&quot;http://www.huffingtonpost.com/entry/great-pacific-garbage-patch-aerial-survey-ocean-cleanup_us_57f2c33be4b01b16aafe80a5&quot; rel=&quot;noreferrer&quot;&gt;article&lt;/a&gt;, they point out that the size of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Pacific_garbage_patch&quot; rel=&quot;noreferrer&quot;&gt;Great Pacific Garbage Patch&lt;/a&gt; is much larger than previously thought.  They go on to say that they are developing a technology that will clean up some of the garbage:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The organization hopes to deploy its Pacific array in 2020 and says it could remove almost half of the Great Pacific Garbage Patch ― more than 150 million pounds of trash ― in a decade.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is great news if it actually works out.  However, how much garbage will still be retained at the sea floor (or suspended below the level at which the garbage can be removed)?&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorDisplayName="user11318" LastEditDate="2017-11-06T13:31:45.037" LastActivityDate="2018-03-28T14:21:12.683" Title="How much garbage goes into the Pacific Ocean every year?" Tags="|ocean|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9004" PostTypeId="2" ParentId="388" CreationDate="2016-11-02T10:29:57.200" Score="2" Body="&lt;p&gt;Air usually subsides at 30 degrees because at that latitude it is cool enough to allow it to sink.&lt;/p&gt;&#xA;&lt;p&gt;Your question on why air rises at 60 degrees; this is not because of convection since insolation (how much solar radiation reaches the Earth's surface) is no longer really intense here, but instead due to frontal uplift. When warm air meets cooler air masses from the poles at roughly 60, it being less dense is forced to rise over the cool air masses.&lt;/p&gt;&#xA;" OwnerUserId="6896" LastEditorUserId="2470" LastEditDate="2023-11-14T18:22:43.527" LastActivityDate="2023-11-14T18:22:43.527" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="9005" PostTypeId="1" CreationDate="2016-11-02T10:36:33.800" Score="1" ViewCount="2902" Body="&lt;p&gt;&lt;em&gt;What is the internal heat engine of the Earth?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Doing research, I found out that the external heat engine of the Earth is the Sun. However, when I did research on the internal heat engine of the Earth, I received multiple answers. Are there multiple answers to this question?&lt;/p&gt;&#xA;" OwnerDisplayName="user6865" LastActivityDate="2016-11-27T03:15:31.357" Title="Earth's Internal Heat Engine" Tags="|geothermal-heat|earth-system|sun|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9006" PostTypeId="1" CreationDate="2016-11-02T10:45:16.047" Score="8" ViewCount="7585" Body="&lt;p&gt;I know &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Geology&quot; rel=&quot;noreferrer&quot;&gt;Geology&lt;/a&gt;&quot; is a branch of &quot;Natural sciences&quot; and is for studying natural and physical phenomena related to earth. But &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Natural_geography&quot; rel=&quot;noreferrer&quot;&gt;Physical Geography/Natural Geography&lt;/a&gt;&quot; seems to study exactly the same thing. What is the main difference between these two fields of study?&lt;/p&gt;&#xA;" OwnerUserId="6895" LastActivityDate="2022-04-08T06:57:06.947" Title="Difference between &quot;Geology&quot; and &quot;Physical(Natural) Geography&quot;?" Tags="|geology|geography|terminology|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9007" PostTypeId="2" ParentId="9005" CreationDate="2016-11-02T11:28:19.953" Score="2" Body="&lt;p&gt;For this question, &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth&amp;#39;s_internal_heat_budget&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; is probably your best recourse. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To summarize, the heat in the earth's core comes from two places: it is left over from the formation of the earth and it is still being generated by radioactive decay of isotopes that were trapped in the earth as it formed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The radiogenic heat is still being added to the earth through decay of long lasting isotopes. When the earth formed, there were probably many significant heat generating isotopes, but now after 4.5 billion years, it is pretty much just Thorium-232, Uranium-238, Potassium-40, and Uranium-235.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So there are multiple answers to this question in the sense that there are the two sources listed above, but otherwise, no, this is the answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/258/how-is-heat-transferred-from-the-core-through-the-mantle-to-the-crust?rq=1&quot;&gt;This question&lt;/a&gt; has some more information related to heat transport to the surface that you may find relevant. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-11-02T11:28:19.953" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9009" PostTypeId="2" ParentId="9006" CreationDate="2016-11-02T12:49:18.507" Score="3" Body="&lt;h2&gt;Geology&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Geology deals with the solid Earth below our feet: composition of rocks, dating of rocks, plate tectonics, identifying natural resources below the ground. It might also deal with the composition of the solid part of other planets - but I am not sure about that.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Physical Geography&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Phyical geography deals with the planet as a whole, including atmosphere, oceans, ground water, and partly 'what is living on the planet'. Climate modeling can also be considered as a part of physical geography.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Summary&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Thus, phyiscal geography is broader than geology when it comes to the Earth surface and consideres also the compartments air and water. In contrast, geology goes deeper into the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From my feeling, geology is more focussed on the past/history of the Earth, whereas physical geography is more about understanding what is happing now and what will happen in future.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2016-11-02T12:49:18.507" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9010" PostTypeId="2" ParentId="9006" CreationDate="2016-11-02T13:03:17.650" Score="6" Body="&lt;p&gt;Physical Geography is a wide area of study - there is many sub-disciplines in this field, such as Biogeography, Climatology, Hydrology, Pedology, Geomorphology (and others as well). Often the scale interesting for the physical geographer is the recent past and future, calculated in thousand of years before today up to a few million (time scale could vary in the recent past (last few years and up to the glaciations and Pleistocene at large). Further, it is focused on surface processes, and not necessarily on rocks, there is a lot more interest in dirt, soils, looses pebbles, and their dynamics of erosion and deposition, the processes affecting the surface. A physical geographer will enjoy hunting for deposits exposure when in the field, so a wall of ancient dirt stratae.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, the Geology field is interested in longer period of time, in rocks, often very deep rocks, the internal geodynamics (mantle, core, magma), will consider the disposition of crystals, petrology, geochemistry of rocks. Otherwise, geologist will be interested in the same topics that physical geographer do, but will use different tools, or consider those topics as a factor among many. Geologist may be mingling with the engineering world better than geographers. They will hunt for outcrops in the field, like intact, in situ rocks that can explain something about the site.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To illustrate this, when I go in the field with geologists, I prefer to bring a shovel, they bring a hammer (I bring one too but will choose the shovel over!). We will enjoy the accessibility to a drill to make boreholes, but will be happy with the first 5 meters depth where they would be interested more in deeper drilling. Further, I will be glad to drill in soils and dirt, where they would definitely prefer in rocks.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2016-11-02T13:03:17.650" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9011" PostTypeId="1" CreationDate="2016-11-02T13:21:41.883" Score="8" ViewCount="1616" Body="&lt;p&gt;Phase transition usually means changing from liquid to solid phase. But in geology literature we come across transitions from one mineral to other mineral. For example olivine-spinel transition at 410 km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is difference between this transition from other phase transitions like solid-liquid, liquid-gas or solid-gas transitions?&lt;/p&gt;&#xA;" OwnerUserId="5557" LastEditorUserId="725" LastEditDate="2016-11-03T04:06:09.563" LastActivityDate="2017-05-18T01:28:11.953" Title="What is meant by phase-change in mantle?" Tags="|geophysics|minerals|mantle|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9013" PostTypeId="2" ParentId="9011" CreationDate="2016-11-02T19:55:16.090" Score="4" Body="&lt;p&gt;'Phase change' doesn't just mean liquid-gas-solid changes. It also includes mineral lattice restructuring in response to differing pressure-temperature conditions. There are also other solid-solid transitions that can take place in response to changes in pH, redox and flux concentrations. In the latter case, the flux is typically high-temperature-water, CO&lt;sub&gt;2&lt;/sub&gt;, F, Cl, B and a few more exotic catalysts. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case of liquid-gas-solid phase changes there are triple points where all three phases exist at a specific &lt;em&gt;P&lt;/em&gt;–&lt;em&gt;T&lt;/em&gt;, and where the distinction between these phases begins to blur. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With increasing depth in the Earth, the pressure increases, resulting in several potential phase changes, of which the olivine-spinel transition is the most obvious because olivine is such a major component of the outer mantle. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="725" LastEditDate="2017-05-18T01:28:11.953" LastActivityDate="2017-05-18T01:28:11.953" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9015" PostTypeId="2" ParentId="9006" CreationDate="2016-11-02T22:25:21.663" Score="4" Body="&lt;p&gt;There is overlap of course, but &gt;90% of most geology courses deal with topics which don't come into physical geography, such as geochemistry, geophysics, petrology and mineralogy, hydrogeology, economic geology,and palaeontology. Some 'Earth Sciences' courses are wider in scope, encompassing meteorology, oceanography and climatology - all of which have differing degrees of overlap with physical geography. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sedimentology and plate tectonics are generally thought of as geological topics. I wouldn't include these as 'physical geography', but others might.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The topic of physical geography has also changed in scope over the years, now being heavily linked to the nature and practice of 'geographic information systems', and 'remote sensing'. Again there is overlap, but geology is still a distinct range of topics which is separate, complementary to, and much greater than physical geography in scope. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-11-02T22:25:21.663" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9016" PostTypeId="1" CreationDate="2016-11-03T02:22:46.987" Score="4" ViewCount="49" Body="&lt;p&gt;I am writing an essay and cannot find if a hurricane is influenced by the position of the sun or the hour of the day.&lt;/p&gt;&#xA;" OwnerUserId="6815" LastEditorUserId="12549" LastEditDate="2018-08-16T08:56:53.810" LastActivityDate="2018-08-16T08:56:53.810" Title="Does the hour of the day and the position on the sun have any influences on the formation of a hurricane?" Tags="|meteorology|tropical-cyclone|earth-observation|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9017" PostTypeId="1" CreationDate="2016-11-03T03:05:43.797" Score="1" ViewCount="324" Body="&lt;p&gt;Where there is snow on the ground, it is a clear indicator that winter in near or already here. Meaning the oceans waters will be colder. But can hurricanes still form in such weather?&lt;/p&gt;&#xA;" OwnerUserId="6815" LastActivityDate="2018-01-06T06:45:29.057" Title="When there is snow on the ground, can a hurricane still form?" Tags="|meteorology|tropical-cyclone|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9018" PostTypeId="2" ParentId="9011" CreationDate="2016-11-03T04:06:21.667" Score="5" Body="&lt;p&gt;I'd like to add to Gordon's answer. A phase change in this context does not only refer to the change in the state of matter (e.g. liquid to solid) but a change in different solid states as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Olivine, $\ce{(Mg,Fe)2SiO4}$, is the stable magnesian silicate in pressures down to those prevailing at a depth of ~410 km below the surface of the Earth. As the mantle is mostly made out of magnesium, silicon and oxygen, this mineral is one of the dominant phases (or minerals) down there. But what happens below 410 km? Using geophysical methods, we know that something changes in the properties of the bulk mantle:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fIzqq.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fIzqq.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are &quot;jumps&quot; in the densities and seismic velocities. From experimental work, we know that olivine changes to wadsleyite and ringwoodite at these pressures. Both wadsleyite and ringwoodite are chemically similar to olivine, their composition is also $\ce{(Mg,Fe)2SiO4}$. However, because of the high pressure, their structure changes from the olivine structure to a denser, more compact spinel structure. Note that this is not spinel the mineral ($\ce{MgAl2O4}$), but rather the olivine composition with the ions arranged the same way the ions are arranged in spinel.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At 660 km, the &quot;spinel&quot;-olivine changes to &quot;perovskite&quot;-olivine, causing the second discontinuity. This perovskite is not the mineral perovskite ($\ce{CaTiO3}$), but rather a magnesium silicate with the perovskite structure ($\ce{(Mg,Fe)SiO3}$). Here's a summary of the phases (i.e. minerals) you find in the Earth's mantle:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/b8UKw.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/b8UKw.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both figures are taken from this &lt;a href=&quot;http://www.uni-muenster.de/Physik.GP/Seismologie/Projekte/ss-pp-precursors.html&quot; rel=&quot;noreferrer&quot;&gt;excellent Uni Münster website&lt;/a&gt;, where you can see the high-res figures and read some more about it.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-11-03T04:06:21.667" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9020" PostTypeId="2" ParentId="9017" CreationDate="2016-11-03T13:37:37.213" Score="6" Body="&lt;p&gt;First off, hurricanes form in tropical seas over warm water. In general, they form in places where it never snows at all. Also, they form over the ocean, and it is hard to have snow on the ground in the ocean. So in that sense, the answer is: &lt;strong&gt;No, hurricanes cannot form in a place where there is snow on the ground&lt;/strong&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, you may mean to ask can a hurricane show up to a place where there is snow on the ground. This is a little more difficult.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wikipedia's &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_off-season_Atlantic_hurricanes&quot; rel=&quot;noreferrer&quot;&gt;off-season Atlantic hurricane&lt;/a&gt; page lists 21 hurricanes that formed in Dec-Feb. Of special interest is the &lt;a href=&quot;https://en.wikipedia.org/wiki/1952_Groundhog_Day_tropical_storm&quot; rel=&quot;noreferrer&quot;&gt;1952 Groundhog day tropical storm&lt;/a&gt; which hit Cape Cod on Feb 4th and Maine Feb 5th of that year. Hyannis, MA had 2 inches of snow on Jan 28th of that year, which melted by Feb 1st (temp data found &lt;a href=&quot;http://climodtest.nrcc.cornell.edu/&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;). It dropped to 30 degrees F the night of the 3rd before the hurricane hit. &#xA;The airport in Bangor, ME had snowfall the 28th and 29th of January which persisted on the ground until the 3rd of February. The night of the 4th dropped to 21 degrees F before the hurricane hit on the 5th.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In both cases, temperatures got into the 40s and heavy precipitation while the storm was passing assuredly melted the snow on the ground. But in that sense of your question: &lt;strong&gt;Yes, hurricanes can strike somewhere with snow on the ground, although the warm air and rainfall of the hurricane will probably melt that snow&lt;/strong&gt;. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="6703" LastEditDate="2016-11-03T13:57:53.127" LastActivityDate="2016-11-03T13:57:53.127" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="9021" PostTypeId="1" CreationDate="2016-11-03T14:50:58.130" Score="1" ViewCount="282" Body="&lt;p&gt;It seems to be an accepted fact that Theropod dinosaurs evolved into present-day birds, but I am still leery of this theory. Can biologists and paleontologists really compare these distinct animals and conclusively show that they are &quot;one-in-the-same&quot; creature, based upon certain morphological similarities?  Is this idea &quot;set in stone?&quot;&lt;/p&gt;&#xA;" OwnerUserId="6905" LastActivityDate="2016-12-10T15:05:34.563" Title="Dino-birds or &quot;Pigeon-o-saurus&quot;" Tags="|paleontology|evolution|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9022" PostTypeId="2" ParentId="9021" CreationDate="2016-11-03T15:18:45.397" Score="7" Body="&lt;p&gt;First, let me link a variety of popular science articles which can give you some background explanation. Here are &lt;a href=&quot;https://www.scientificamerican.com/article/how-dinosaurs-shrank-and-became-birds/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scientific American&lt;/a&gt;, &lt;a href=&quot;http://www.smithsonianmag.com/science-nature/dinosaurs-living-descendants-69657706/?no-ist&quot; rel=&quot;nofollow noreferrer&quot;&gt;Smithsonian&lt;/a&gt;, and &lt;a href=&quot;http://www.audubon.org/magazine/january-february-2015/which-came-first-dinosaur-or-bird&quot; rel=&quot;nofollow noreferrer&quot;&gt;Audubon&lt;/a&gt; magazines. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The 'smoking gun' evidence linking birds and dinosaurs is the evolution of feathers. Feathers are a feature that set the birds apart morphologically from the rest of the tetrapods, and indeed from the rest of all animals. All birds have feathers and nothing that isn't a bird has feathers. So a logical place to start looking for the origin of birds is the origin of feathers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the dawn of modern paleontology, there had always suspected links between dinosaurs and birds due to the fossils of &lt;a href=&quot;https://en.wikipedia.org/wiki/Archaeopteryx&quot; rel=&quot;nofollow noreferrer&quot;&gt;Archaeopteryx&lt;/a&gt; found in the 1860s. &lt;a href=&quot;https://en.wikipedia.org/wiki/Sauropsida#Huxley_and_the_fossil_gaps&quot; rel=&quot;nofollow noreferrer&quot;&gt;Thomas Huxley&lt;/a&gt; claimed the two groups were related as early as 1863. But it wasn't until recent decades that the fossil record started being filled in with definitive links between Archaeopteryx and therapod dinosaurs, such as more species intermediate between birds and therapods and fossil impressions indicating that some therapods had feathers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rest is just filled in by logical deduction, or &lt;a href=&quot;https://en.wikipedia.org/wiki/Occam&amp;#39;s_razor&quot; rel=&quot;nofollow noreferrer&quot;&gt;Occam's Razor&lt;/a&gt;. There is clear evidence that all birds have feathers, and no other animals alive today have feathers. There is now clear evidence that therapods had very similar skeletons to birds with feathers about 150 million years ago. There is also evidence that many therapods had feathers, a trait otherwise confined to birds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let our null hypothesis be that the origin of birds is unknown, and our alternative hypothesis be that birds evolved from dinosaurs. Given the similarities noted above (and, keep in mind, the evidence is much stronger for scientists who specialize in this area), do you think there is enough evidence to reject the null hypothesis and conclude that birds evolved from dinosaurs? If not, are there any plausible alternative hypotheses?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The great thing about science is that you never have to take someone else's word for it. Everyone has the right to be a skeptic, just keep an open mind and look at the evidence and you can draw your own conclusions. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-11-03T15:18:45.397" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="9023" PostTypeId="2" ParentId="9003" CreationDate="2016-11-03T15:42:05.767" Score="5" Body="&lt;p&gt;I've been looking for information on non-plastic garbage, and haven't had much luck. Plastic waste is an extensively researched topic. I don't have access to  &lt;a href=&quot;http://science.sciencemag.org/content/347/6223/768&quot; rel=&quot;nofollow noreferrer&quot;&gt;Jambeck et al., &lt;em&gt;Science&lt;/em&gt; 2015&lt;/a&gt;, but I did find a graphic and summary. The numbers are all year-long totals for 2010.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9yJ4F.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9yJ4F.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The study's estimated range of plastic entering the ocean is 4.8 million to 12.7 million metric tons (MMT). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the United States we can find some other figures to try to complete the picture. According to the &lt;a href=&quot;https://www.epa.gov/sites/production/files/2015-09/documents/2012_msw_fs.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;EPA&lt;/a&gt;, in 2012, the US generated 251 MMT of municipal solid waste (MSW). Of that, 11.7% was burned, 34.5% was recovered by some sort of recycling, and 53.8% was discarded (Fig. 4). Plastics compose 12.7% of pre-recycling waste but 17.6% of post-recycling waste. Biodegradables (here I'm using food, paper, yard trimmings, and wood, but not textiles) consist of 61.7% of trash before recycling and 52.8% after.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if we assume those ratios can be applied to the plastics sent to the ocean (8 MMT) you get the following:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Assuming global ocean waste has a similar composition as US&#xA;non-recycled waste, there are 63 MMT garbage entering the sea, of&#xA;which 39 MMT are biodegradable. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Assuming global ocean waste has a similar composition as US recycled&#xA;waste, there are 45 MMT garbage entering the sea of which 24 MMT are&#xA;biodegradable.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="6703" LastEditDate="2017-11-09T16:57:27.523" LastActivityDate="2017-11-09T16:57:27.523" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9025" PostTypeId="1" CreationDate="2016-11-03T18:36:10.147" Score="2" ViewCount="221" Body="&lt;p&gt;While there have been lots of studies looking at the effect of greenhouse gasses on increasing temperatures around the planet, my question is what are the effects of emissions on food production. &lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="5536" LastEditDate="2016-11-03T21:41:13.297" LastActivityDate="2018-04-20T00:39:43.143" Title="Which greenhouse gas does the most damage to crops?" Tags="|climate-change|agriculture|greenhouse-gases|" AnswerCount="4" CommentCount="3" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9026" PostTypeId="2" ParentId="9025" CreationDate="2016-11-03T20:23:02.697" Score="2" Body="&lt;p&gt;Specifically looking at carbon dioxide, there's been a series of field experiments that involve artificially raising the local &lt;code&gt;CO2&lt;/code&gt; levels for different plant species and seeing how they reallocate this carbon and develop. Results from the &lt;a href=&quot;http://www.nature.com/scitable/knowledge/library/effects-of-rising-atmospheric-concentrations-of-carbon-13254108&quot; rel=&quot;nofollow noreferrer&quot;&gt;Free Air Concentration Experiments (FACE)&lt;/a&gt; have been published for the past 25 years and can be found in some pretty major journals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some major findings are that the expected yields from carbon enriched plant species aren't as high as previously estimated, and that the rise of ground level ozone associated with higher carbon levels is damaging plant capacity for photosynthesis.&lt;/p&gt;&#xA;" OwnerUserId="5536" LastActivityDate="2016-11-03T20:23:02.697" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9027" PostTypeId="2" ParentId="9025" CreationDate="2016-11-03T22:03:01.187" Score="3" Body="&lt;p&gt;To add to Trevor's answer, FACE experiments have shown that elevated CO&lt;sub&gt;2&lt;/sub&gt; can affect grain quality and the food product.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example &lt;a href=&quot;http://www.smh.com.au/environment/un-climate-conference/what-climate-change-will-do-to-your-loaf-of-bread-20150619-ghshcq.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;bread made with wheat flour grown under elevated CO&lt;sub&gt;2&lt;/sub&gt; doesn't rise as much as flour from identical varieties grown under current conditions.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1242" LastEditorUserId="725" LastEditDate="2017-05-18T01:25:11.273" LastActivityDate="2017-05-18T01:25:11.273" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9029" PostTypeId="1" AcceptedAnswerId="9033" CreationDate="2016-11-03T22:47:05.393" Score="1" ViewCount="975" Body="&lt;p&gt;Laccolith, lobolith and batholith are shapes of igneous rocks which exist below the surface of the earth, dikes and sills too. And the way they formed by makes me think that they have a porphyritic texture, is that right? Or they have a coarse-grained texture? Because they have crystalled below the earth surface anyway?&lt;/p&gt;&#xA;" OwnerUserId="6908" LastActivityDate="2016-11-04T03:12:02.353" Title="are laccolith, lobolith, dikes and sills formed of porphyritic texture?" Tags="|geology|structural-geology|igneous|metamorphism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9030" PostTypeId="1" CreationDate="2016-11-03T23:50:41.993" Score="4" ViewCount="77" Body="&lt;p&gt;I live in Hamilton Ontario which a major city right on the shore of Lake Ontario, and I was just doing some personal research on the pollution levels in lake Ontario. Generally the water here has a negative stigma of being dirty, and I was just wondering, are the lakes getting cleaner, or like greenhouse gases; It depends where you are talking about.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was always under the impression that the factories here in Hamilton Harbor were a large source of pollution, and apparently they were at one point, but now days its non point source pollution that is apparently creating the most pollution in Lake Ontario.&lt;/p&gt;&#xA;" OwnerUserId="6910" LastActivityDate="2016-11-03T23:50:41.993" Title="Are the Great Lakes Getting Cleaner, or worse?" Tags="|water|pollution|water-table|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9031" PostTypeId="1" CreationDate="2016-11-04T00:14:55.027" Score="4" ViewCount="1459" Body="&lt;p&gt;Atmospheric carbon dioxide levels have been rising, recently passing 400 parts per million.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;CO&lt;sub&gt;2&lt;/sub&gt; is a &lt;a href=&quot;https://en.wikipedia.org/wiki/Greenhouse_gas&quot; rel=&quot;noreferrer&quot;&gt;greenhouse gas&lt;/a&gt;; it absorbs and emits radiation in the thermal infrared range. It is, as far as I know, quite transparent in the visible range.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we could see in the infrared range that's most affected by CO&lt;sub&gt;2&lt;/sub&gt;, would the increased levels be visible? Would the sky appear darker because more infrared is being absorbed? Or perhaps brighter because more is being emitted and/or reflected? Or just a different color?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would an infrared photograph of the sky taken, say 100 years ago in an unpopulated area look significantly different from one taken today?&lt;/p&gt;&#xA;" OwnerUserId="429" LastActivityDate="2017-05-18T01:24:04.213" Title="Do rising CO2 levels change the appearance of the sky in infrared?" Tags="|co2|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9032" PostTypeId="1" AcceptedAnswerId="9041" CreationDate="2016-11-04T01:39:02.050" Score="3" ViewCount="325" Body="&lt;p&gt;The Science article &lt;a href=&quot;http://www.sciencemag.org/news/2016/11/average-us-family-destroys-football-fields-worth-arctic-sea-ice-every-30-years&quot; rel=&quot;nofollow noreferrer&quot;&gt;The average U.S. family destroys a football field's worth of Arctic sea ice every 30 years&lt;/a&gt; states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;http://science.sciencemag.org/content/early/2016/11/02/science.aag2345&quot; rel=&quot;nofollow noreferrer&quot;&gt;Every additional metric ton of carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) puffed into the atmosphere appears to cost the Arctic another 3 square meters of summer sea ice.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;which carries a link to the abstract of a peer-reviewed Science paper &lt;a href=&quot;http://science.sciencemag.org/content/early/2016/11/02/science.aag2345&quot; rel=&quot;nofollow noreferrer&quot;&gt;Observed Arctic sea-ice loss directly follows anthropogenic CO&lt;sub&gt;2&lt;/sub&gt; emission&lt;/a&gt;. However the abstract says (in part):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Since climate-model simulations of the sea-ice loss differ substantially, we here use a robust linear relationship between monthly-mean September sea-ice area and cumulative CO&lt;sub&gt;2&lt;/sub&gt; emissions to infer the future evolution of Arctic summer sea ice directly from the observational record. The observed linear relationship implies a sustained loss of 3 ± 0.3 m&lt;sup&gt;2&lt;/sup&gt; of September sea-ice area per metric ton of CO&lt;sub&gt;2&lt;/sub&gt; emission.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My question is about the simplification of linking tons of CO&lt;sub&gt;2&lt;/sub&gt; to square meters of ice, and without reference to time. The abstract seems to simply say that there appears to be a linear relationship, and since models disagree, then this is a &quot;good enough&quot; way to think about it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it so simple - if in 2017 no CO&lt;sub&gt;2&lt;/sub&gt; were burned the sea ice would return to normal? No. The summer sea ice would likely continue to decrease for decades. An analogy might be births and deaths of a population. While there might be a rough (or &quot;robust&quot;) correlation between birth rate and death rate, a cessation of births in a given year would have almost no impact on death rate for perhaps a half-century. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any mathematics that justifies this simple &quot;robust linear relationship&quot; to be causal? What does &quot;directly follows&quot; mean?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm &lt;em&gt;not in any way&lt;/em&gt; questioning the causality between CO&lt;sub&gt;2&lt;/sub&gt; and a wide variety of changes in climate, including reduction in summer sea-ice. I'm only questioning the original quote and the quantitative relationship: &lt;em&gt;1 metric ton of CO&lt;sub&gt;2&lt;/sub&gt; costs 3 square meters of summer sea ice&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aiOL3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aiOL3.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1dtZo.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1dtZo.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;above x2:&lt;/strong&gt; Graphics from &lt;a href=&quot;http://www.sciencemag.org/news/2016/11/average-us-family-destroys-football-fields-worth-arctic-sea-ice-every-30-years&quot; rel=&quot;nofollow noreferrer&quot;&gt;Science Magazine&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="725" LastEditDate="2017-05-18T01:26:27.363" LastActivityDate="2017-05-18T01:26:27.363" Title="How can every ton of CO2 cost 3 square meters of summer sea ice per year - quantitatively?" Tags="|climate|climate-change|co2|sea-ice|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9033" PostTypeId="2" ParentId="9029" CreationDate="2016-11-04T03:12:02.353" Score="1" Body="&lt;p&gt;Laccoliths, lopoliths, dikes and sills are all characteristic modes of occurrence of hypabyssal rocks, generally small in scale compared to most magma chambers. They are magmas which have cooled in a near-surface environment. None of these terms &lt;em&gt;necessarily&lt;/em&gt; implies a particular petrologic texture. So, for example a dike or sill may be aphanitic, porphyritic, aplitic, pegmatitic or even glassy obsidian - and other less common textures. Nevertheless, many hypabyssal rocks &lt;em&gt;are&lt;/em&gt; porphyritic. All this means is that the magma crystallized in two stages. The first stage was deeper and slower cooling, allowing some crystals to grow, sometimes to much larger size than the rest of the crystalline matrix. The second stage is when the magma is intruded at shallow depth, resulting in much more rapid crystallization of the remaining melt. Hence the porphyritic texture of large crystalls within a fine-grained matrix. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-11-04T03:12:02.353" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9034" PostTypeId="1" AcceptedAnswerId="9035" CreationDate="2016-11-04T08:42:31.943" Score="3" ViewCount="3633" Body="&lt;p&gt;I am busy with the development of an &quot;environment&quot; model that can be used for flight simulation of all kinds of flight vehicles — ranging from quad-copters, unmanned aerial vehicles, manned aircraft, up to rocket launchers for satellites.  The model consists of sub-models for terrestrial gravity; the earth's size, shape, and motions; the geomagnetic field; the atmosphere; and so on.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Currently I am using the &lt;a href=&quot;http://www.sparc-climate.org/data-center/data-access/reference-climatologies/cira-86/&quot; rel=&quot;nofollow noreferrer&quot;&gt;COSPAR International Reference Atmosphere (CIRA-86)&lt;/a&gt; to calculate air pressure and temperature for heights up to 120 km. But, to be able to calculate air density, I also need to model the effects of humidity.  I know that water vapour is only present in varying quantities in the troposhere, and that high humidity is therefore more likely at lower altitudes.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anybody have models of the probability of experiencing some value of relative humidity as a function of height above sea level?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit.&lt;/strong&gt; As an example of what I really need, the MIL-F-8785C model for wind speed and turbulence, for example, gives the mean wind speed at a height of 6.1 m above the ground, given the logarithm of the probability of exceeding the wind speed. So, a model of the humidity as a probability of exceeding the the mean humidity as a function of height is what I really need.  Do you know of any models that provide this?&lt;/p&gt;&#xA;" OwnerUserId="6664" LastEditorUserId="6664" LastEditDate="2016-11-04T13:05:42.047" LastActivityDate="2016-11-04T13:05:42.047" Title="How does humidity vary with height in the Earth's atmosphere?" Tags="|atmosphere-modelling|humidity|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9035" PostTypeId="2" ParentId="9034" CreationDate="2016-11-04T11:20:33.020" Score="4" Body="&lt;p&gt;Humidity &lt;strong&gt;strongly&lt;/strong&gt; varies as a function of time and space, which is why standard atmospheres like CIRA may choose to omit it at all.  It simply doesn't make sense to include an “average” humidity profile, because such an average is not meaningful.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, there are other sources for relative humidity profiles.  You can obtain them from reanalysis data.  If you want probabilities, you could calculate them from reanalysis.  I have not used probabilities, but I have used profiles from Anderson et al. (1986) in the past:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anderson, G. P., S. A. Clough, F. X. Kneizys, J. H. Chetwynd, and E. P. Shettle (1986), AFGL atmospheric constituent profiles (0–120 km), AFGL, TR-86-0110.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anderson transcribes them in his paper, which is in PDF and not ideal to read.  The same data are distributed along with the &lt;a href=&quot;http://www.radiativetransfer.org&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atmospheric Radiative Transfer Simulator&lt;/a&gt; (see also &lt;a href=&quot;https://en.wikipedia.org/wiki/ARTS_(radiative_transfer_code)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia article&lt;/a&gt;).  This radiative transfer model comes with a set of XML files, that includes profiles from both CIRA and from Anderson et al.  Those are not probabilities but “typical” H₂O profiles for five scenarios: tropical, mid-latitude summer, mid-latitude winter, sub-arctic summer, and sub-arctic winter.  For example, a mid-latitude summer H₂O profile can be found &lt;a href=&quot;https://arts.mi.uni-hamburg.de/trac/rt/browser/arts-xml-data/trunk/planets/Earth/Fascod/midlatitude-summer/midlatitude-summer.H2O.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;at this link&lt;/a&gt;.  The data are in XML so should be easy to read, but they also provide reading routines for Matlab and Python.  The unit is volume mixing ratio, which may actually be more suitable than relative humidity if you are interested in calculating air density.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2016-11-04T11:25:43.733" LastActivityDate="2016-11-04T11:25:43.733" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9037" PostTypeId="1" CreationDate="2016-11-04T22:01:27.770" Score="2" ViewCount="1367" Body="&lt;p&gt;I have determined an area to be along the coastline just from looking at its climagraph. Its temperatures only range from -10 to 21 so there is not a large range of temperatures because it is being moderated by the ocean. However now I need to see if the wind speeds provided back my answer up. The windspeeds range from 10.7 km/hr to 15km/hr and there is only 8 days a year where the windspeeds are greater or equal to 52km/hr. So I was not given the name of this location but just from this information about windspeeds I need to back up my answer saying that this region is a coastline region. But how do I go about that?&lt;/p&gt;&#xA;" OwnerUserId="6915" LastEditorUserId="5536" LastEditDate="2016-11-05T05:07:35.553" LastActivityDate="2016-12-05T05:45:00.760" Title="Determing whether an area is Inland or Coastal" Tags="|climate|temperature|wind|coastal|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9038" PostTypeId="1" CreationDate="2016-11-05T03:20:51.943" Score="8" ViewCount="1732" Body="&lt;p&gt;I have heard numerous reasons why that is. I just want to know which one is right.&lt;/p&gt;&#xA;" OwnerUserId="6916" LastActivityDate="2020-10-18T05:34:47.897" Title="Why is it colder in the mountains than at sea level?" Tags="|meteorology|atmosphere|temperature|atmospheric-chemistry|atmospheric-radiation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9039" PostTypeId="2" ParentId="9037" CreationDate="2016-11-05T03:46:55.440" Score="2" Body="&lt;p&gt;Well, let's start with a rough global map (from NCEP Reanalysis) of the average winds speeds (in meters per second):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/CunMj.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CunMj.png&quot; alt=&quot;NCEP Reanalysis 1981-2010, see http://www.esrl.noaa.gov/psd/cgi-bin/data/composites/printpage.pl for making your own&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Multiply by 3.6 to get km/hr.  So your range is basically from 3 m/s to 4 m/s.  So you're looking at the medium blue color basically.&#xA;There are some coastal locations.  But generally, coastal locations will have quite a bit of wind...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cn26J.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cn26J.jpg&quot; alt=&quot;Wind friction effects, courtesy Environment Canada&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What this graphic says is that basically winds at the ocean are 15-60% increased from typical land values.  Even more upsetting to being coastal is the 8 days less than 52 km/hr that you mention.  You're in a location reasonably mid-latitude, so you've traditionally got the big wind storms that often affect the coastal areas, such as Nor'Easters, and Bering Sea cyclones.  I'd think it'd be hard to find an oceanic city that doesn't get above 52 km/hr more than 8 days during a year outside the tropics (assuming you're talking about short burst of 52 km/hr and not daily averages, but even daily averages I'd think might surpass 52 km/hr 8 days per year in the majority of seaboard cities).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I'd be surprised to see that it is truly a coastal location.  However there are a couple places with connections to water that might fit still.&lt;br&gt;&#xA; 1 - Near inland seas\lakes would have somewhat lower wind because of the diminished water fetch available and the decreased percentage of the year that wind flows over such water.&#xA; 2 - The transition zone from marine winds to land winds is probably only something like 10-100 miles, while temperature moderation is still significant, even moreso if there is water on many sides.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because your temperature range is only indeed 31 C (56 F) wide, that certainly does seem to still suggest it has significant moisture influences.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, 21 C seems a fairly cool value (especially if that's the absolute maximum daytime peak during the year, but even an average of 21 seems a tad cool, especially for cities not right on the water.&#xA;So that suggests to me that it's pretty far north, or perhaps abuts rather cool waters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, looking at the map, and based upon those ideas, I'd think the favorite might be inland Russia or China... or maybe around Italy\Greece.  Just the right city location in the northern US or Canada might work too, like Portland (Oregon), Detroit, or Ottawa.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2016-11-05T03:46:55.440" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="9040" PostTypeId="2" ParentId="4717" CreationDate="2016-11-05T03:55:10.750" Score="0" Body="&lt;p&gt;Earthquakes are measured by their energy which is in magnitude. Richter scale was a numerical calculation and used before moment magnitude scale is used. Nowadays we use magnitude rather than richter scale. &#xA;&lt;a href=&quot;http://www.whatcausesearthquakes.com/how-are-earthquakes-measured.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;How measuring earthquakes&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6917" LastActivityDate="2016-11-05T03:55:10.750" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9041" PostTypeId="2" ParentId="9032" CreationDate="2016-11-05T04:07:52.457" Score="1" Body="&lt;p&gt;First lets take the question at face value and do the simple comparison. I will take the years 1979 and 2016 as arbitrary example, over a 37 year period - the longest for which accurate data are available. During that time the minimum extent of Arctic sea ice, defined as the area of Ocean with at least 15% of sea ice (as determined by satellite) decreased from 6.93 to 4.14 million square kilometers. That is, a decrease of 2.79 M Km2. The actual ice loss was much greater because of ice thinning, but that is incidental to the question. During the same period the CO2 emissions by the USA increased by about 160 M tonnes. So on the face of it, assuming a direct linear relationship, 1 tonne of emitted carbon from America results in an average of 0.029 km2 reduction in ice, or about 3 hectares (Not Km2! let's get the units correct!).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, as every scientist knows, a correlation - even a good correlation, doesn't necessarily imply causation. In this case it would be correct to say that every tonne of burned coal eventually &lt;em&gt;contributes&lt;/em&gt; towards the loss of Arctic ice, but the whole process is much more complex, with an abundance of other contributing factors, feedback processes, and non-linear relationships coming into play. Among these complicating factors are Arctic ice thinning, changing Arctic albedo, changing ocean-scale oscillations, Other country emissions, inter-annual changes in thermal inertia (land, ice, sea and atmosphere), and high-level atmospheric chemistry (volcanic gasses, aerosols, etc.). So although there is an element of truth in your article, it would be naive to imply a direct relationship.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To keep an eye on how the Arctic ice is responding to climate change I highly recommend &#xA;&lt;a href=&quot;http://nsidc.org/arcticseaicenews/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://nsidc.org/arcticseaicenews/&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-11-05T04:07:52.457" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9042" PostTypeId="1" CreationDate="2016-11-05T04:38:36.987" Score="1" ViewCount="5107" Body="&lt;p&gt;I don't know why, but I have noticed my whole life that the sky's blue color seems saturated in winter and sort of pale, milky, and washed out in the summer. Does it have to do with the angle of the sun during seasons and/or the absolute humidity?&lt;/p&gt;&#xA;" OwnerUserId="6916" LastActivityDate="2016-11-05T23:14:47.007" Title="Why is the sky bluer in winter than in summer?" Tags="|atmosphere|atmospheric-chemistry|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9043" PostTypeId="2" ParentId="9038" CreationDate="2016-11-05T07:43:44.983" Score="14" Body="&lt;p&gt;The traditional answer basically comes down to the physics concept of adiabatic cooling, a description of which is:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;There is less pressure as you go up in the atmosphere (basically due to less air weighing down)&lt;/li&gt;&#xA;&lt;li&gt;Air takes up more volume at lower pressures&lt;/li&gt;&#xA;&lt;li&gt;Since there's nothing else to supply the energy needed to expand, the air employs the energy that was in the temperature (which is the amount of air molecule movement).  The result is that air higher up is cooler by about 10 C per km (for dry air... moisture releases heat, reducing the cooling to about 6 C per km)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;But, in summary, &lt;strong&gt;air is cooler higher up&lt;/strong&gt; in the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;And that is certainly the dynamics explaining why air temperature decreases as you go up throughout the troposphere (the only layer of the atmosphere we generally encounter in our lives... other things do come into play in other layers... such as ozone collecting and rereleasing energy from the sun in the stratosphere, actually causing warming with height there).&lt;/p&gt;&#xA;&lt;p&gt;However, it seems that this typical explanation actually falls short.  Because if you pay attention to the wording of that &amp;quot;because air higher in the atmosphere is cooler&amp;quot; phrase, it doesn't actually answer the question.&lt;/p&gt;&#xA;&lt;p&gt;Because all locations you're considering are surface locations, whether they're at sea level or in the mountains.&lt;/p&gt;&#xA;&lt;p&gt;And the surface layer basically does all the absorbing of the troposphere's sunlight (the solar radiation absorbed by the troposphere is negligible).&#xA;And after all, mountainous places receive the same amount solar energy as lower elevation sites (in fact, technically a tiny bit more, that tiny tiny bit I mentioned that the troposphere takes out for sea-level locations).&lt;/p&gt;&#xA;&lt;p&gt;Where am I going with this?&lt;/p&gt;&#xA;&lt;p&gt;If the ground gets the same energy.  And if it's made of the same material and has the same color, it would therefore gain the same amount of temperature.  And then the air's heating comes up from the ground below.&lt;/p&gt;&#xA;&lt;p&gt;So then, once again, why are mountains cooler?!?&lt;/p&gt;&#xA;&lt;p&gt;Because of their &lt;strong&gt;EXPOSURE&lt;/strong&gt;.&lt;br /&gt;&#xA;Air predominantly flows horizontally rather than vertically (basically consider this an effect of gravity and the resultant air density distribution).&#xA;And it's that horizontal wind that changes everything.  Because most sites on mountains are generally quite proximate (at least regionally) to places where winds will blow in air that was higher above the lower elevation ground surface, and thus colder.  The air on mountains, with limited protection (and because winds are higher aloft) is mixed strongly with the neighboring adiabatically cooler air that's sitting above the sea-level sites.&lt;/p&gt;&#xA;&lt;p&gt;Just for more convincing this is vital, I invite you to look at these climatographs comparing two cities in the US.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4Qckj.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4Qckj.png&quot; alt=&quot;2 cities, red data taken from NOAA, blue from Intellicast&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;What are these towns?&lt;br /&gt;&#xA;Red: Wendover, Utah (elevation 4,291', latitude 40.73° N)&lt;br /&gt;&#xA;Blue: Latrobe, Pennsylvania (elevation 997', 40.32° N)&#xA;Over a km difference in height.  So you'd expect Latrobe to be about 18°F warmer.&lt;br /&gt;&#xA;But it isn't.  Instead it's cooler (especially during summer afternoons, which average up around 10 degrees apart).&lt;br /&gt;&#xA;Why?  Because a lot of the intermountain west is actually quite a wide flat elevated basin\plateau.  So in the central part of this area, there isn't as much exposure to the colder air coming in from places with lower topography.&lt;/p&gt;&#xA;&lt;p&gt;Rest assured, it was very hard to find examples like this.  You need a very wide flat elevated area, which is fairly uncommon.  Plus just the right place to compare to for emphasis.&lt;/p&gt;&#xA;&lt;p&gt;There are other common factors that do enhance the cold predilection on mountains, including the lower moisture content at elevation, the often lighter land color of raised terrain, and the increased cloud coverage due to air rising orographically.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;But the fundamental reason it is colder on mountains is &lt;strong&gt;adiabatic cooling&lt;/strong&gt; and the &lt;strong&gt;exposure&lt;/strong&gt; of raised locations to that colder air.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2020-10-18T05:34:47.897" LastActivityDate="2020-10-18T05:34:47.897" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="9044" PostTypeId="2" ParentId="9025" CreationDate="2016-11-05T10:24:35.080" Score="3" Body="&lt;p&gt;Quantitatively hydrogen fluoride is insignificant, except when it is emitted from volcanic sources, in which case it is extremely toxic to crops - far more than any other natural gas. Possibly the worst recorded case was from Iceland when the volcanic eruption of 1783-1794 killed most if not all the crops and livestock downwind. The combination of fluorine poisoning and ensuing famine eventually killed some 10,000 people, or 22% of Iceland's population. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Strictly HF itself is not a 'greenhouse gas', but it reacts rapidly in the upper atmosphere to form other greenhouse gasses, such as CFCs, perfluorocarbons, and the extremely potent GHG, sulphur hexafluoride. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-11-05T10:24:35.080" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9045" PostTypeId="2" ParentId="9031" CreationDate="2016-11-05T13:29:58.463" Score="3" Body="&lt;p&gt;Due to man made climate change, from space, the Earth currently looks a little darker in Infra-red (IR) and a little colder (longer wavelength), but the change is small and would be hard to notice without sensitive photon-counting equipment.   The earth doesn't exactly glow in steady color in IR either, it swirls and looks like a circulating, 100% cloud covered planet, which makes sense when you consider that our atmosphere, mostly the H&lt;sub&gt;2&lt;/sub&gt;O and CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere is opaque to much of the infrared spectrum, so it looks a little like Venus in the IR, but not quite as dense with clouds.   What's more, you'd see seasonal variations and day/night variations, so it would be hard to notice a pretty small climate variation over that.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;See YouTube video and article of the Earth in IR: &lt;a href=&quot;https://youtu.be/3a70A3XYfIE?t=39s&quot; rel=&quot;nofollow noreferrer&quot;&gt;Planet Earth in Infrared (Synchronized)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and the article: &lt;a href=&quot;http://www.slate.com/blogs/bad_astronomy/2015/02/02/water_vapor_ir_video_of_the_earth_from_space.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Our Planet Has the Vapors&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The video isn't quite right, because it's only one wavelength designed to track water-vapor not the entire IR spectrum, but I thought it was close enough to use as a starting point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The short answer is, at least for now, the Troposphere is warming but the stratosphere is cooling and contracting, so from space, in IR, Earth is both a little smaller and a little colder/darker, at least, for now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The longer answer is that when the Earth is in energy equilibrium, that is, not undergoing climate warming or cooling, the Earth gives back to space  the same amount energy it receives from the Sun, at least, more or less.  There's some variation, but it's largely the same.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only way Greenhouse driven warming can happen, is for the Earth to hoard heat, and gives back less heat to space than it takes in from the sun.   When the Earth grows colder, it's the opposite, the Earth needs to return more energy to space than it takes in from the sun.  This variation doesn't have to be all that big, for example, a fraction of 1% variation over enough time can be enough to start or end an ice age, but that's the only way warming or cooling can happen.  It has to be an imbalance in Earth's energy equilibrium (technically, also, it could be a change in Earth's orbit or a solar minimum), but Earth's orbital changes take tens of thousands of years and Earth's climate changes mostly take 1,000 or so, and solar minimums are relatively weak and thought to only last a couple hundred years or so.  So the primary driver for climate change, warmer or colder, man made or natural, is the Earth hoarding or losing energy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This doesn't have to happen entirely in infrared.  Changes in albedo/reflection can play a role too, for example, as snow cover and permanent glaciers grow, the visible light reflected off earth gradually but steadily increases resulting in the Earth giving back more energy than it takes in, leading to a cooling, sometimes an ice age, and the energy imbalance continues until the Earth is sufficiently cooled to reach a new equilibrium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Currently, the Earth is hoarding heat and it's albedo is relatively unchanged, meaning that it's giving back less IR into space than it used to, so, in IR, the Earth looks a little bit darker than it used to before man made climate change.   Ballpark, about 1% darker in the IR.   As to changes in color, there's some variation in wavelength on both warmer and colder, but on average, slightly colder/longer wavelengths.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Estimates vary, but, ballpark, Earth is trapping roughly 2 extra watts of energy per square meter due to climate change and most of that trapped energy/heat goes into the oceans, very gradually warming them.  The lower atmosphere is more effectively absorbing and reflecting thermal radiation from the surface so less IR is reaching the upper atmosphere and less is going into space, so while the surface of the Earth does grow brighter in IR what is mostly seen from space is the cooling upper atmosphere.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Over time, as the Earth's surface and lower atmosphere grows warmer, it will emit more IR and the upper atmosphere will, in time, give back into space just as much IR as it used to before climate change, and probably more, but that will take 100 years or so, perhaps longer.   Also, as Earth's ice cover drops and it's oceans rise, Earth's albedo will mean less visible light is being reflected into space, so the thermal radiation will need to increase to make up for that.  So, in a century or two, the warmer Earth should glow brighter in IR and on average, a bit warmer/shorter wavelength, too.   How much will depend mostly on how much ice cover melts, but we're probably not looking at more than maybe a 1% increase, 2% tops.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For some numbers and pretty charts, see &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_energy_budget&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth is hit by about 340–341 watts per square meter of energy from the sun, that's on average, summer/winter, equator/poll and night/day.  Direct sunlight on a perpendicular surface to the Sun's rays is about 4 times that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of that 340–341 watts, currently about 29% or 100 watts is directly reflected back into space as mostly visible light.  The remaining 240 or so watts (per m&lt;sup&gt;2&lt;/sup&gt;) leaves the Earth in the form of infra-red or thermal radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;About 170 watts of that 240 comes from the high atmosphere.  About 30 from cloud tops and about 40 watts from surface radiation.   While the Earth's surface does grow warmer during climate change and brighter in IR, 90% of that gets re-absorbed by or reflected back by the atmosphere and only 10% reaches space, so the added brightness you might expect to see off the warmer surface makes up only a small part of the total.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we say the Earth's surface has warmed about 0.8 °C, say from 288K to 288.8K, using the 4th power rule, that should emits about 1% more thermal energy than it did before climate change, but 1% of 40 watts comes to about 0.4 watts per square meter increase, and perhaps decreased overall due to the more opaque atmosphere with higher CO&lt;sub&gt;2&lt;/sub&gt;.   The biggest factor for the earth's IR image is the temperature of the upper atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an FYI, there are other imbalances to the heat in/heat out equilibrium equation, for example, a really big volcano might release enough heat into the surface to unbalance the ratio temporarily and following a big volcano there's an increase in the amount of light reflected off earth which leads to a relatively rapid but temporary cooling.   A large enough meteor impact could also create a variation, and the Earth is hit by solar wind and cosmic rays and it loses some heat in very fast moving particles that exceed escape velocity (mostly hydrogen from water molecules).  The Earth also has internal heat coming from it's warm interior, which means the Earth does emit a bit more heat than it receives overall, at least on average, which does throw off the expected equilibrium a little bit.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;And, final and curious sidebar, you might ask, how the Earth's surface can emit 400 watts per square meter, which is more energy than Earth receives from the sun.  That has nothing to do with your question though, but it's a curious statistic I think.   It's because our atmosphere acts like a blanket, warming the Earth overall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope that wasn't tl;dr.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="725" LastEditDate="2017-05-18T01:24:04.213" LastActivityDate="2017-05-18T01:24:04.213" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9046" PostTypeId="1" CreationDate="2016-11-05T17:49:21.863" Score="1" ViewCount="5840" Body="&lt;p&gt;I was wondering if the difference between the low temp and the high temp depended on just the humidity content and the altitude of a place. Or are there more factors? What about the time of year? How would the time of year affect diurnal temp variation if it does affect the range?&lt;/p&gt;&#xA;" OwnerUserId="6916" LastActivityDate="2016-11-21T21:45:45.723" Title="What factors affect daily temperature range?" Tags="|meteorology|geophysics|atmosphere|climate|temperature|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9049" PostTypeId="2" ParentId="9042" CreationDate="2016-11-05T23:14:47.007" Score="3" Body="&lt;p&gt;The angle of the sun and humidity, indeed have a major effect on the color of the sky. To start, when there is a higher humidity level there is obviously a greater quantity of water vapor in the atmosphere. This leads to more of what is called &lt;a href=&quot;http://www.severewx.com/Radiation/scattering.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mie scattering&lt;/a&gt;. Mie scattering in this scenario is when the water vapor and water droplets direct more blue spectrum of light back into space causing you to see a smaller portion then what is possible with less scattering. Depending on where you live the seasons vary for when there is the least amount of humidity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now secondly, if you live between 30-60 degrees North or South, the suns angle changes enough, that the spectrum of light is affected. When the sun is closer to the horizon, the light is traveling through more atmosphere than it would if the sun were directly above. This leads to &lt;a href=&quot;https://en.wikipedia.org/wiki/Rayleigh_scattering&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rayleigh scattering&lt;/a&gt;, which end and end directs more blue light to your eyes.&lt;/p&gt;&#xA;" OwnerUserId="6921" LastActivityDate="2016-11-05T23:14:47.007" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9050" PostTypeId="1" CreationDate="2016-11-06T00:24:55.320" Score="5" ViewCount="45015" Body="&lt;p&gt;In different regions, the sun is directly overhead at different times of the year. When do these event happen?&lt;/p&gt;&#xA;" OwnerDisplayName="user6865" LastEditorUserId="6298" LastEditDate="2018-01-30T05:53:34.817" LastActivityDate="2020-09-01T21:26:06.453" Title="What time and date is the sun directly overhead a given place on Earth?" Tags="|planetary-science|earth-observation|seasons|sun|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="9052" PostTypeId="1" CreationDate="2016-11-06T12:32:07.610" Score="9" ViewCount="11544" Body="&lt;p&gt;We know that oxygen comes from trees and plants (photosynthesis), so in the jungle where there are a lot of trees you would expect more oxygen than in the desert where there are no trees. Walking in the desert is tough, but is that also due to there being less oxygen?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know oxygen averages about 21% of the air.  Diffusion and winds probably means there is at least enough oxygen to live in the deserts and on the poles.  But could the oxygen perhaps be lower in those regions, and what is the minimum percentage that humans need to live?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="6298" LastEditDate="2016-11-07T11:31:50.513" LastActivityDate="2021-10-15T12:06:04.543" Title="Is oxygen spread equally on Earth's surface?" Tags="|atmosphere|atmospheric-chemistry|oxygen|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9054" PostTypeId="2" ParentId="9052" CreationDate="2016-11-07T00:24:57.703" Score="1" Body="&lt;p&gt;Vegetative photosynthesis does indeed have a significant effect upon atmospheric oxygen concentrations, as may be seen in the plots of the&#xA;&lt;a href=&quot;http://scrippso2.ucsd.edu/plots&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atmospheric Oxygen Research&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The strong seasonal variation in photosynthesis, particularly in high latitude northern hemisphere regions, results in an annual oxygen fluctuation of about 20 ppm (parts per million). Superimposed upon this is the 'dilution effect' of increasing carbon dioxide, mainly due to the burning of fossil fuels, such that we are effectively losing about 19 oxygen molecules per million every year. These effects are far less than the short-term fluctuations in available oxygen caused by the weather. &#xA;You are correct in saying that the mean oxygen concentration is about 21%. Compare this to the optimal breathing range, for humans, of 19.5 to 23.5% oxygen. People tend to lose consciousness at about 10% oxygen, and die of asphyxiation at about 5% or less. &#xA;The above data are for sea-level. At high mountain altitudes the oxygen can be as little as 12%, which is why it is so difficult to climb the highest Himalayan peaks. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Taking the long perspective, even at sea level there has been a a large variation in oxygen content in the atmosphere over the last 550 million years, varying between 10% and 35%. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Don't worry, the human physiology is more than capable of handling &lt;em&gt;normal&lt;/em&gt; fluctuations and trends in the atmosphere's oxygen content. But here is  something which you might want to worry about: Suppose international efforts to curb greenhouse gas emissions are negated by continued human population growth? A worst-case scenario can be contemplated in which the global mean temperature rise attains, or even exceeds, 4.5 degrees Celsius during some time next century. In this case, at least a billion people, mainly in the tropics, will be subjected to extreme seasonal heat-stress. At the same time the cumulative effects of oxygen dilution in the atmosphere might become sufficiently high to exacerbate that heat-stress. This is a scenario that &lt;em&gt;does&lt;/em&gt; have the potential to kill people. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="6093" LastEditDate="2016-11-07T14:49:48.757" LastActivityDate="2016-11-07T14:49:48.757" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9055" PostTypeId="2" ParentId="9052" CreationDate="2016-11-07T03:11:59.423" Score="3" Body="&lt;p&gt;Based upon links from a &lt;a href=&quot;https://chemistry.stackexchange.com/questions/27546/how-chemically-homogeneous-is-air&quot;&gt;similar question&lt;/a&gt; on atmospheric distribution in &lt;a href=&quot;https://chemistry.stackexchange.com/&quot;&gt;Chemistry SE&lt;/a&gt;, I looked into the latitudinal difference by making a couple images using the MSIS model chemistry &lt;a href=&quot;http://ccmc.gsfc.nasa.gov/modelweb/models/msis_vitmo.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;plotting website&lt;/a&gt; (using Janauary 1, 2016, 100 W longitude, 0 km altitude)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/b7vLc.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/b7vLc.gif&quot; alt=&quot;Air Concentration&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I understand it, this suggests there is over 15% less oxygen at some latitudes than others.  But that it's still approximately the same percentage of the overall air.  As to why:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5FSWi.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5FSWi.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically latitudinal differences are due to temperature.  Lower temperature means greater air density means more air (and oxygen).  See PV=nRT\Charles' Law.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I played with latitudinal cross-sections to see if I could spot any geographic issues, but this image from &lt;a href=&quot;https://tools.wmflabs.org/wp-world/googlmaps-proxy.php?page=https:%2F%2Ftools.wmflabs.org%2Fkmlexport%3Farticle%3D30th_parallel_north&amp;amp;output=classic&quot; rel=&quot;nofollow noreferrer&quot;&gt;30 north&lt;/a&gt; (which crosses the dry\arid US desert southwest, the fairly green US southeast, the northern Sahara, dry areas of the Arabian desert, Iran, and Tibet, and then fairly green southeast China:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RkjSK.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RkjSK.gif&quot; alt=&quot;longitudinal cross section&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Still no significant variability apart from temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I couldn't find information on the grid spacing or on what the model accounts for (it could be possible that the model doesn't even take into account land coverage, though that would seem to very poor when modeling atmospheric chemistry!!).  But if this model has fair validity, it suggests there generally is very little difference due to landcover over large-areas; wind mixing makes the air extremely homogeneous.&#xA;But this doesn't speak entirely to how much very local differences may exist, such as in a parking lot versus a patch of trees.  Still, the effects apparently are unlikely to be very significant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Perhaps walking in the desert is tough primarily because of the dry air\dust\heat\elevation?&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2016-11-07T03:11:59.423" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9056" PostTypeId="1" CreationDate="2016-11-07T15:01:28.220" Score="3" ViewCount="169" Body="&lt;p&gt;I received seismic data for which I would like to remove the instrumental response. The only information I have is that they were recorded on a Trillium broadband seismometer with a cutoff period of 40s.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I assumed it referred to the trillium 40 for which I found the following &lt;a href=&quot;https://www.passcal.nmt.edu/webfm_send/948&quot; rel=&quot;nofollow noreferrer&quot;&gt;user guide&lt;/a&gt;. Some information is given about poles and zeros at pages 40-41 but it is unclear to me which one I should use. Besides, I intend to manually define them using &lt;a href=&quot;https://docs.obspy.org/tutorial/code_snippets/frequency_response.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Obspy&lt;/a&gt; but I am not entirely sure of how to do it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At this point, I was planning to copy &lt;a href=&quot;https://stackoverflow.com/questions/16071620/python-how-to-transform-counts-in-to-m-s-using-the-obspy-module&quot;&gt;this example&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6933" LastActivityDate="2016-11-07T15:01:28.220" Title="How to find instrumental response for a seismic station" Tags="|seismology|instrumentation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9057" PostTypeId="1" CreationDate="2016-11-07T19:25:01.270" Score="1" ViewCount="110" Body="&lt;p&gt;I am trying to figure out what type of precipitation lifting mechanism occurs in a area that is unknown but I know some facts about the climate. So I know that there are 4 precipitation lifting mechanisms - frontal, convection, convergent and orographic. So based off the extreme daily precipitation I need to choose one of these and back up my statement. So I have concluded that the area is inland because the temperature range is from -10 to 20, which is larger than most coastal temperature ranges. So I am hoping that this fact will eliminate one of the lifting mechanisms. So the extreme daily precipitation goes as follows.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Jan:65mm&lt;br&gt;&#xA;Feb:54mm&lt;br&gt;&#xA;Mar:64mm&lt;br&gt;&#xA;Apr:75mm&lt;br&gt;&#xA;May:80.3mm&lt;br&gt;&#xA;June:92.8mm&lt;br&gt;&#xA;Jul:92mm&lt;br&gt;&#xA;Aug:86mm&lt;br&gt;&#xA;Sep:90mm&lt;br&gt;&#xA;Oct:87mm&lt;br&gt;&#xA;Nov:82mm&lt;br&gt;&#xA;Dec: 76.4  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What type of lifting mechanism is responsible for the most extreme precipitation events? Then I need to back it up with the amount of days with the winds greater then 52km/hr which is only 8, and the yearly average wind speed is only 12.9.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My thinking is that I don't believe its orographic. But I am not sure which it is out of the other 3. There is not much wind all year around so this must be a factor, and there is a moderated amount of extreme precipitation all year around(shown by the data I provided)&lt;/p&gt;&#xA;" OwnerUserId="6934" LastActivityDate="2016-11-07T22:32:01.730" Title="Wind speed, precipitation, extreme daily precipitation" Tags="|climate|wind|precipitation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9058" PostTypeId="1" AcceptedAnswerId="9066" CreationDate="2016-11-07T22:15:03.823" Score="2" ViewCount="937" Body="&lt;p&gt;I'm doing some research about tectonic plates and at which speeds they move and in which directions, because I'm writing a program to simulate the movement of the tectonic plates and also calculate where they were at previous times and where they will be at some time in the future.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For this reason, I'm trying to find some good information about the speeds of the movement of the tectonic plates over the years and in which direction they were moving. I found one set of estimates &lt;a href=&quot;http://hypertextbook.com/facts/ZhenHuang.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; but I'm not exactly sure how accurate they are. I also found estimates on the Wikipedia pages for each of the plates, but it doesn't agree with the first estimate and I also want to know how significantly these speeds are changing over time (I assume the movement of the plates is not linear).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, the first site doesn't give in which direction they are moving and Wikipedia does, but I don't quite understand it - it says, for example &quot;west relative to the African plate&quot;, and I'm not sure what exactly that means.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any help would be appreciated here. Thanks!&lt;/p&gt;&#xA;" OwnerUserId="6935" LastActivityDate="2016-11-09T05:22:07.890" Title="Speed of tectonic plate movement" Tags="|plate-tectonics|earth-history|simulation|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9059" PostTypeId="2" ParentId="9058" CreationDate="2016-11-07T22:24:30.023" Score="2" Body="&lt;p&gt;Check out the USGS seismic data maps for each area of interest. For example, &#xA;&lt;a href=&quot;http://walrus.wr.usgs.gov/tsunami/samoa09/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://walrus.wr.usgs.gov/tsunami/samoa09/&lt;/a&gt; &#xA;gives you the relative speed and direction of the Pacific Plate relative to the Fiji-Tonga-Australian plate. The directional arrow on Figure 2 gives the mean relative motion in mm/year.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-11-07T22:24:30.023" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9060" PostTypeId="2" ParentId="9057" CreationDate="2016-11-07T22:32:01.730" Score="1" Body="&lt;p&gt;Sometimes it is obvious, but it may not be possible to attribute the rainfall mechanism from the daily rainfall. Also, the four lifting mechanisms are not 'either / or'. There are frequently combinations of the above, particularly in respect of the most extreme events.  &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-11-07T22:32:01.730" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9061" PostTypeId="1" CreationDate="2016-11-08T01:36:48.403" Score="5" ViewCount="162" Body="&lt;p&gt;We know that the current SETI efforts have not found evidence for the existence of intelligent exo-civilizations (XCIV). There also has not been any evidence found of ancient non-human civilizations in the fossil record. One possibility, among many, is that XCIVs only exist for a geologically short amount of time before collapsing/extinction. Then, it could be possible that, even though none exist now, one or more XCIV could have existed in the past, and it was capable of transmitting electromagnetic (EM) radiation signals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, consider the following hypothesis:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;In the last 100 million years, at least one XCIV capable of emitting directed EM radiation existed within 100 light-years of our solar system.&lt;/li&gt;&#xA;&lt;li&gt;The CIV sent directed EM beams towards all the planets in the star systems surrounding it.&lt;/li&gt;&#xA;&lt;li&gt;Based on what it could detect about each planet's composition, it designed the beams (frequency, signaling pattern, modulation, etc...) such that they would leave as large of a mark on the targeted planet's geologic record as possible (the mark).&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question: Is there any form of patterned, extra-solar EM radiation that could theoretically leave a mark in the geologic record that could be recognizable to us as such up to 100 million years later? And could a human-level civilization be capable of projecting such beams?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6936" LastActivityDate="2016-11-09T05:15:29.927" Title="Could evidence of a signal from an exocivilization be found in the geologic record?" Tags="|geology|geophysics|astrobiology|astronomy|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9062" PostTypeId="2" ParentId="8956" CreationDate="2016-11-08T02:46:09.373" Score="3" Body="&lt;p&gt;The age of the tide (a.k.a, &lt;a href=&quot;http://co-ops.nos.noaa.gov/publications/glossary2.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;age of phase inequality&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Lunitidal_interval&quot; rel=&quot;nofollow noreferrer&quot;&gt;lunitidal interval&lt;/a&gt;) at a location is a term that denotes the interval between the time of a Full or New Moon (when the equilibrium semi-diurnal tide force is maximum), and the time of the local spring tide. In most cases, there is a delay between maximum forces and occurrence of maximum elevation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The tidal forces generate waves of very long wavelength that travel all around the ocean with a velocity determined by the shallow water progressive wave velocity equation, $c=\sqrt(gH)$, where $H$ is water depth. The delay between the moon phases and their effect on the tide is the time that it takes for the wave to travel around the ocean. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two different mechanisms to consider: resonance and friction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fact that the age of the tide is analogous to the increase of the phase lag of a forced, linearly damped harmonic oscillator as the frequency increases was known since the XIX century. The damped oscillator analogy does not explain the phase magnitudes in the real ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The inclusion of friction is necessary to explain the observed time lags. &lt;a href=&quot;http://dx.doi.org/10.1111/j.1365-246X.1941.tb00439.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;Proudman (1941)&lt;/a&gt; showed that by including frictional effects on coastal areas, a positive age of tide appear in the tidal solution. If there is some resonant frequency in an ocean basin close to the semi-diurnal frequencies ($M_2$, $S_2$...), friction enhances the age of the tide resulting in higher delay values. &lt;a href=&quot;http://dx.doi.org/10.1016/0011-7471(71)90073-8&quot; rel=&quot;nofollow noreferrer&quot;&gt;Garrett &amp;amp; Munk (1971)&lt;/a&gt; and &lt;a href=&quot;http://dx.doi.org/10.1016/0011-7471(73)90006-5&quot; rel=&quot;nofollow noreferrer&quot;&gt;Webb (1973)&lt;/a&gt; provided a methodology for the calculation and estimates around the oceans. The longest delays (longer than 60 hours) were estimated in areas with the largest continental shelf, as they represent areas of strong tidal dissipation: the North Sea, the Ross Sea, Hudson Strait, the shelf off Argentina, the Bering Sea, and the Sea of Okhotsk.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The age of tide can be obtained from the harmonic constants by dividing the difference in phases of the $S_2$ and $M_2$ constituents by frequency separation between both constituents: &#xA;$ Age\_of\_tide = {Phase\_of\_M_2 - Phase\_of\_S_2 \over 1.0163 }$, where the phases are measured in degrees and the age of tide is in hours.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2016-11-08T02:46:09.373" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9063" PostTypeId="2" ParentId="9061" CreationDate="2016-11-08T07:39:35.923" Score="2" Body="&lt;p&gt;&lt;strong&gt;No&lt;/strong&gt;, it is not possible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only thing I could think about is re/de/magnetisation of magnetic minerals. Even then I'm not sure it's feasible, because you to form a magnetic field you need an electric current in motion, but that's a question for physics, not here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far, the major magnetic signals recorded in the geological history are well understood. There are many small scale signals that are less well understood, and are believed to be the result of internal processes within the Earth. You can look at my answer &lt;a href=&quot;https://earthscience.stackexchange.com/a/6802/725&quot;&gt;here&lt;/a&gt; for examples of these signals. Anyway, even if an extraterrestrial civilisation could somehow affect the geological record, it would have to be sustained for very long times (hundreds to thousands of years) for us to be able to see something, and even then we probably wouldn't be able to distinguish it from noise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an example, think of a river with rocks in it, constantly getting moved and tumbled. Then you go and throw a rock inside. There would be absolutely no way to know which rock was it (and even that someone threw a rock inside), even a day later, let alone 100 million years. The only way to distinguish something would be a huge amount of rocks, not just one. And then there's the question, of why would someone spend this enormous amount of energy of throwing rocks in the river or sending EM beams towards planets?&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-11-08T07:39:35.923" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9064" PostTypeId="1" AcceptedAnswerId="9073" CreationDate="2016-11-08T16:57:18.213" Score="2" ViewCount="102" Body="&lt;p&gt;I'm not sure if this is the correct place to ask this. Basically I have an exercise in dynamic meteorology that is set up like this:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;1 kg of dry air is falling with a constant speed of 0.5 cm / s and 0.1&#xA;  w/kg of heat is extracted. Does the air volume temperature rise, fall&#xA;  or does it remain unchanged?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Here's how I tried to solve it:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$w = 0.5 \frac{cm}{s}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$J= -0.1 \frac{w}{kg}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$T? $&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$J = Cp \frac{dT}{dt} - \alpha  \frac{dp}{dt}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$J = Cp \frac{dT}{dt} - \frac{1}{\rho}  \frac{dp}{dt}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\frac{dp}{dt} = \frac{\delta p}{\delta t} + u  \frac{\delta p}{\delta x} + v \frac{\delta p}{\delta y} + w \frac{\delta p}{\delta z} = w \frac{\delta p}{\delta z}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(because $\frac{\delta p}{\delta t} + u  \frac{\delta p}{\delta x} + v \frac{\delta p}{\delta y} = 0$)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$ \frac{\delta p}{\delta z} = -\rho g$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\frac{dp}{dt} = w \frac{\delta p}{\delta z} = w -\rho g$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$J = Cp \frac{dT}{dt} - \frac{-1 w \rho g}{\rho} = Cp \frac{dT}{dt} + \rho g$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\frac{dT}{dt} = \frac{J-gw}{Cp} = \frac{-0.1 \frac{w}{kg} - 9.81 \frac{m}{s^2}   0.5 \frac{cm}{s}}{1004.5 \frac{J}{K * kg}} $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's where I get lost. Any help?&lt;/p&gt;&#xA;" OwnerUserId="6937" LastEditorUserId="111" LastEditDate="2016-11-08T17:01:01.603" LastActivityDate="2021-09-05T13:39:57.703" Title="Dynamic meteorology - calculating air temperature based off falling air" Tags="|meteorology|temperature|homework|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9065" PostTypeId="2" ParentId="9061" CreationDate="2016-11-09T05:15:29.927" Score="2" Body="&lt;p&gt;You can just think of this in terms of energy. To leave a mark in the geologic record, you have to use something that is at least as strong as the forces that are shaping the world around you: erosion, melting, tectonic forces, wind and weather. These are all very energetic things that are happening around us all the time, and for long time spans. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to compete with this, and leave a recognizable, permanent mark on Earth, you have to have something that is at least as energetic. That is difficult already for humans to achieve (though we do -- we have significantly accelerated erosion, and our moving of rocks and earth will clearly be distinguishable for a long time to come). But think of what it would take to do this from several light years away? Even a well focused laser beam would be far larger than Earth at these distances, meaning that you would have to send your laser beam with a far larger power and duration than the processes on Earth, just to leave a bit of a mark. This is clearly not possible.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2016-11-09T05:15:29.927" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9066" PostTypeId="2" ParentId="9058" CreationDate="2016-11-09T05:22:07.890" Score="2" Body="&lt;p&gt;You will want to look at the GPlates program and its references to where it gets its data from. It is probably the most widely used repository to show plate motion information for the current time as well as far into the past.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as the &quot;...relative to the African plate&quot; part is concerned: If you are sitting somewhere on the moon, and look for long enough time (let's say, a few million or tens of millions of years), you will see plates move about over the surface of the earth. But because you only see the surface of the earth, you cannot distinguish the following two cases: (i) all plates move westward, (ii) the earth just rotates a wee bit slower than you thought. That's because you don't have a coordinate system that is anchored &quot;in the Earth&quot; (e.g., rotates at the same speed as the Earth core) with respect to which you can determine what moves where. As a consequence, all we can do is describe &lt;em&gt;relative&lt;/em&gt; motions of plates. One convenient way to do this is to choose a coordinate system in which one of the plates remains stationary (e.g., the African plate) and all others move.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2016-11-09T05:22:07.890" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9067" PostTypeId="1" AcceptedAnswerId="9132" CreationDate="2016-11-09T16:23:38.387" Score="2" ViewCount="223" Body="&lt;p&gt;I am studying the L.C. King's &quot;Normal Cycle of Erosion&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apparently, he suggests that Davis was incorrect to have assumed Temperate Humid conditions as &quot;normal conditions&quot; of the world when suggesting his (Davisain) Normal Cycle of Erosion. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;King goes on to suggest that it should be &quot;semi-arid&quot; conditions instead which should be assumed to be &quot;normal conditions&quot; (representative of the world's climate) and hence, suggested his (King's) &quot;Normal Cycle of Erosion&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So &lt;strong&gt;my questions&lt;/strong&gt; are:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;How did L.C. King define SemiArid climate?&lt;/li&gt;&#xA;&lt;li&gt;How much area in the world is under SemiArid climate as defined by L.C. King?&lt;/li&gt;&#xA;&lt;li&gt;How much area in the world is under Temperate climate?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;P.S.: I suppose if a figure isn't available for Temperate/SemiArid climate, a figure for the 6 Temperate Biomes and the 3 SemiArid Biomes would also do the trick...&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;6 Temperate Biomes: Warm Temperate Eastern Margin (China/Gulf Type), Warm Temperate Continental (Steppe Grasslands Type), Warm Temperate Western Margin (Mediterranean type), Cool Temperate Eastern Margin (Laurentian type), Cool Temperate Continental (Taiga type), Cool Temperate Western Margin (British type).&lt;/li&gt;&#xA;&lt;li&gt;3 Semi Arid Biomes: Warm Temperate Continental (Steppe Grasslands Type), Warm Temperate Western Margin (Mediterranean type), Tropical Grasslands (Savanna type)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6939" LastEditorUserId="6939" LastEditDate="2016-11-18T05:10:41.110" LastActivityDate="2016-11-18T14:07:47.340" Title="How much area in the world is under SemiArid climate?" Tags="|climate|geomorphology|climatology|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9068" PostTypeId="2" ParentId="9067" CreationDate="2016-11-09T16:45:49.477" Score="3" Body="&lt;p&gt;According to this &lt;a href=&quot;http://www.physicalgeography.net/fundamentals/7v.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt; is 14% for Köppen classification.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The precise cite is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;BS - dry semiarid (steppe). Is a grassland climate that covers 14% of the Earth's land surface.&quot;&lt;/p&gt;&#xA;" OwnerUserId="5004" LastActivityDate="2016-11-09T16:45:49.477" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9072" PostTypeId="1" CreationDate="2016-11-10T03:44:50.810" Score="1" ViewCount="78" Body="&lt;p&gt;Earth's sky appears blue, due to the composition of the atmosphere and refraction.  Mars' sky is reddish, due to the high iron-oxide particle content of the air.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a planet had enough vegetation and humidity to keep the air relatively dust-free, and if the air composition was similar to that of Earth, would that planet necessarily have a blue sky, like ours?  Under what conditions could such a planet have a different color sky (yellow, for example) and still support terrestrial-type life? &lt;/p&gt;&#xA;" OwnerUserId="6905" LastActivityDate="2016-11-10T22:00:18.900" Title="Extraterrestrial Planetary Sky Color: does it have to be blue?" Tags="|meteorology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9073" PostTypeId="2" ParentId="9064" CreationDate="2016-11-10T04:58:19.547" Score="2" Body="&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA; \frac{w}{kg} = \frac{J}{kgs} = \frac{Nm}{kgs} = \frac{kgm}{s^2}\frac{m}{kgs} = \frac{m^2}{s^3}&#xA;\end{equation}&lt;/span&gt;&#xA;So, &lt;span class=&quot;math-container&quot;&gt;$J$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$wg$&lt;/span&gt; have same unit, and also your final answer has correct unit, Kelvin per second. Your final answer says the parcel's temperature will drop, even without cooling term &lt;span class=&quot;math-container&quot;&gt;$J$&lt;/span&gt; (you will find this strange because it should be heated by adiabatic heating). It is because you set &lt;span class=&quot;math-container&quot;&gt;$w$&lt;/span&gt;=0.5 instead of &lt;span class=&quot;math-container&quot;&gt;$w$&lt;/span&gt; =-0.5. I hope this helps you :)&lt;/p&gt;&#xA;" OwnerUserId="5400" LastEditorUserId="22648" LastEditDate="2021-09-05T13:39:57.703" LastActivityDate="2021-09-05T13:39:57.703" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="9075" PostTypeId="2" ParentId="9072" CreationDate="2016-11-10T22:00:18.900" Score="1" Body="&lt;p&gt;Not necessarily blue, although pure nitrogen, ozone, methane and hydrogen- cyanide  all appear as various shades of blue (assuming the incoming starlight is white). Nitrogen dioxide would be a deep brownish red. Some organics and chlorine dioxide are yellow, whilst chlorine is yellowish green. There are many other coloured gasses, but they are not likely to form planetary atmospheres. However, the question implies vegetation, and hence Earth-like photosynthesis, in which case it also implies an Earth-like atmosphere, in which case a normally pale-blue sky is inevitable.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-11-10T22:00:18.900" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9076" PostTypeId="1" AcceptedAnswerId="9077" CreationDate="2016-11-10T22:38:14.510" Score="1" ViewCount="147" Body="&lt;p&gt;I've always found geographic visualizations of surface/mixed-layer CAPE models and other weather data to be incredibly interesting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://img.washingtonpost.com/wp-apps/imrs.php?src=https://img.washingtonpost.com/blogs/capital-weather-gang/files/2013/06/hires_cape_washdc_31.png&amp;amp;w=1484&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's a map&lt;/a&gt; featured by the Capital Weather Gang over at the Washington Post, during the June 12-13, 2013 derecho series in the Ohio Valley/Chesapeake Bay regions. It was created by WeatherBELL, which is a subscription service offering visualizations based on their proprietary technology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://1.bp.blogspot.com/-8zL79Alhz3A/U-g9Ff6h8zI/AAAAAAAAbgo/hFu4Q8TDTnY/s1600/mcape.60.0000.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's another map&lt;/a&gt; featured on the blog of Cliff Mass, a professor of atmospheric sciences at the University of Washington. This is an internal UW WRF model that is GFS-initialized.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to know how I can take archived GFS or WRF data and visualize it on a map. Or even if that's possible (perhaps archived numerical data is only available to paid subscribers). What I would like to do is plot surface and upper-air readings to better understand the mesoscale setups for thunderstorms in the Pacific Northwest, where I live.&lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2016-11-10T23:12:44.173" Title="How can I implement a visualization of archived convective data from numerical weather models?" Tags="|meteorology|atmosphere-modelling|weather-forecasting|visualization|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9077" PostTypeId="2" ParentId="9076" CreationDate="2016-11-10T23:12:44.173" Score="2" Body="&lt;p&gt;The best model archive I know of offhand is Iowa State Meteorology's Gempak model data in their &lt;a href=&quot;http://mtarchive.geol.iastate.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;MTArchive&lt;/a&gt;.  Looks like model-wise, they have at least 10 years of GFS (and the predecessor, the AVN).  No idea if the models are complete files (include CAPE) or not, though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.unidata.ucar.edu/software/gempak/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gempak&lt;/a&gt; software is free, though you won't get graphics nearly as polished as WxBell; they've spent a lot of time fine tuning their setup, and likely use newer more flexible tools (probably &lt;a href=&quot;http://cola.gmu.edu/grads/&quot; rel=&quot;nofollow noreferrer&quot;&gt;GrADS&lt;/a&gt; or &lt;a href=&quot;http://opengrads.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;OpenGrADS&lt;/a&gt;, both also free).  You could probably get GrADS to use the .gem files, perhaps by converting them?  &lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2016-11-10T23:12:44.173" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="9078" PostTypeId="1" CreationDate="2016-11-11T01:54:48.343" Score="4" ViewCount="3639" Body="&lt;p&gt;I wanted to know if two earthquakes can happen at the same time in the same area? I &quot;think&quot; this can happen, but I'm not totally sure? I understand tectonic plates sliding against each other can cause an earthquake, but is it possible for two to happen at the same time in the same area?&lt;/p&gt;&#xA;" OwnerUserId="6951" LastEditorUserId="-1" LastEditDate="2018-01-11T07:19:38.910" LastActivityDate="2018-01-11T07:19:38.910" Title="Can two earthquakes happen at the same time?" Tags="|earthquakes|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9079" PostTypeId="2" ParentId="8254" CreationDate="2016-11-11T03:11:28.270" Score="7" Body="&lt;p&gt;It starts by identifying days with good overlay of shear and surface-based instability.  In the US we have the &lt;a href=&quot;http://www.spc.noaa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Storm Prediction Center&lt;/a&gt; that helps indicate such days looking at models.  Generally the very earliest signs that get chaser's attention are a reasonable trough moving into regions with adequate moisture and warmth (sometimes a cut-off upper-level low works too).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then the day before and the morning of the event, final target regions get narrowed down further by looking at visible and water vapor imagery, upper level air maps, and surface weather data.  Basically the focus is generally on surface features... fronts, low pressure centers, drylines, and outflow boundaries.  Chasers will usually get into that region by early afternoon, as supercells and tornadoes are most common during the late afternoon and evening.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once in the target zone, chasers keep an eye on any available satellite imagery, surface weather data, and also to the skies, looking for initial storm developments and any adjustments that may need to be made to the target area.  In many situations, clouds will start &lt;a href=&quot;https://en.wikipedia.org/wiki/Cumulus_congestus_cloud&quot; rel=&quot;nofollow noreferrer&quot;&gt;building up&lt;/a&gt; and perhaps pulsate in development, giving indication of favored areas long before the &lt;a href=&quot;https://en.wikipedia.org/wiki/Capping_inversion&quot; rel=&quot;nofollow noreferrer&quot;&gt;cap&lt;/a&gt; is broken and they develop into supercells.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once the storms get going, the interest become identifying the stronger and more isolated storms as they develop rotation, becoming supercells.  In the northern hemisphere, the &quot;business area&quot; of a supercell is usually near the southern end, where a supercell will typically start to develop some sort of hooked shape, as all shown in this supercell image:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hJh7Y.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hJh7Y.jpg&quot; alt=&quot;Supercell&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;(Source: &lt;a href=&quot;http://thevane.gawker.com/what-is-a-supercell-thunderstorm-1564133584&quot; rel=&quot;nofollow noreferrer&quot;&gt;What is a Supercell Thunderstorm, by Dennis Mersereau, on Vane&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most (though not all) supercells move approximately northeast.  So knowing that, as the day evolves, a typical chaser will make choices to help end up on the south half of the storm so their visibility and path are not blocked by the stronger rain and hail.  Then it comes down to road options, and paying attention to the storm and environment around you to watch whether the rotation is tightening up in the cloud base, as well as being aware of the temperature and wind for indications of how the storm may evolve.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When it comes to models, you're right that they absolutely can't identify the tornado.  However, convective models (like the HRRR) do often indicate the approximate areas where storms will develop a few hours ahead of time.  But it doesn't appear models will be forecasting where tornadoes will form with any great reliability for quite a while still.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But in terms of hunting down tornadic storms, convective models, and for that matter any large deal of real-time data, certainly aren't a necessity.  People have been chasing storms quite successfully long before all that was available.  It's more reasonable than most realize.  You choose the climatologically favorable tornado seasons to start, then seek out favorable areas within the large-scale pattern, and then refine your target by interpreting the conditions until you find yourself magically on the southern end of a hook, &lt;a href=&quot;https://en.wikipedia.org/wiki/Supercell#/media/File:Supercell02.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;even without radar help&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For more input, I also suggest Mike Hollingshead's amazing high quality graphic tutorial, with a very useful snippet &lt;a href=&quot;https://stormandsky.com/stormanalysis101&quot; rel=&quot;nofollow noreferrer&quot;&gt;available on his StormAndSky website&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It looks like tornadoes are &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_tornadoes_tornado_outbreaks_in_Asia&quot; rel=&quot;nofollow noreferrer&quot;&gt;quite regular occurrences&lt;/a&gt; around China.  I know of chasers around Europe, Australia, and South America, but am surprised there aren't more in China.  Maybe that is soon to change?&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-05-30T10:41:03.743" LastActivityDate="2018-05-30T10:41:03.743" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="9080" PostTypeId="1" CreationDate="2016-11-11T03:41:49.410" Score="5" ViewCount="314" Body="&lt;p&gt;Though I imagine it's unlikely there is any significant correlation because daily and annual temperature variation really only impact a fairly shallow layer of the crust, I wondered whether the actual data backs that up.  I could envision a few unlikely causes, such as the expansion\contraction, rainfall amounts, or crazy things like the little differences in earth-sun distance.  So what say you?&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2016-11-11T18:39:25.767" LastActivityDate="2018-09-02T15:05:04.257" Title="Are there any seasonal or diurnal trends in earthquakes?" Tags="|earthquakes|seasons|diurnal-cycle|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9081" PostTypeId="2" ParentId="9080" CreationDate="2016-11-11T04:20:56.067" Score="1" Body="&lt;p&gt;There is a slight tendency for earthquakes in coastal areas to coincide with higher gravitational attraction. In one study in Greece, earthquakes were 15% more likely to occur when the sun's gravitational pull was at a maximum. In general though, seismic-tidal correlations are very weak (but not zero). &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-11-11T04:20:56.067" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9082" PostTypeId="2" ParentId="7283" CreationDate="2016-11-11T11:54:11.867" Score="1" Body="&lt;p&gt;Is not the amount of curvature available to see reduced by looking at it from a very flat angle - ie multiplied by the sine of that small angle? At 35000 feet the horizon is 229 miles away and 440 miles long, with the maximum field of vision of the human eye of 110 degrees (not attainable in practice) so the curvature depth is 78 miles, but because of the flatness of view, it foreshortens to about 2.4 miles (and much less with a narrower field of view). To resolve 2.4 miles at 229 distance over 440 miles miles is going some, or perhaps about 1 mile or less in practice through a window.  Using a telescope does not help as all it does is reduce the angle of the field of view proportionately.&lt;/p&gt;&#xA;" OwnerUserId="6953" LastActivityDate="2016-11-11T11:54:11.867" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9083" PostTypeId="1" CreationDate="2016-11-11T14:34:32.847" Score="0" ViewCount="545" Body="&lt;p&gt;&lt;em&gt;What is the relationship between the latitude and daylight hours for each season?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I interpret the answer for the question, I believe the number of daylight hours decreases as the latitude increases as fall goes to winter. Then, when winter goes to spring, and spring goes to summer, the daylight hours increase as the earth rotates. Though, my answer is vague, in my opinion.&lt;/p&gt;&#xA;" OwnerUserId="6955" LastEditorDisplayName="user6956" LastEditDate="2016-11-11T18:17:05.920" LastActivityDate="2016-11-18T16:32:53.387" Title="Latitude and Daylight Hours" Tags="|earth-rotation|seasons|sun|astronomy|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9084" PostTypeId="1" CreationDate="2016-11-11T15:22:27.943" Score="2" ViewCount="271" Body="&lt;p&gt;I am taking a navigational course and part of it is about meteorology. There is one thing which is, although obvious, quite hard for me to grasp.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looking at a global weather map like this: &lt;a href=&quot;https://earth.nullschool.net&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earth.nullschool.net&lt;/a&gt; I can see the High pressure area on the Atlantic pushing air towards Europe and into the Low pressure area in the North pole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My understanding is that High pressure = Cold air, flowing clockwise and outwards. Viceversa for the Low pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I don't understand is why there is an area of High (cold) over the Atlantic in the tropics and Low (warm) in the Poles, while I would expect the Atlantic to be warmer than the North pole (and indeed it is, if you look at surface temperature). My expectation would be the opposite should happen.&lt;/p&gt;&#xA;" OwnerUserId="6957" LastActivityDate="2017-08-20T22:39:43.197" Title="Why is the Atlantic anticyclone an area of high pressure if it's the warmest spot on the planet?" Tags="|atmosphere|wind|barometric-pressure|atlantic|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9085" PostTypeId="1" CreationDate="2016-11-11T18:40:27.833" Score="1" ViewCount="1700" Body="&lt;p&gt;&lt;em&gt;Since the equator is closest to the sun, would it have more daylight hours compared to, say, the Tropic of Cancer?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am using an example, however, would it be true if the farther one is from the equator, the less daylight hours?&lt;/p&gt;&#xA;" OwnerDisplayName="user6956" LastEditorUserId="1411" LastEditDate="2016-11-11T20:16:01.590" LastActivityDate="2016-11-13T23:48:38.033" Title="Equator and Hours of Daylight" Tags="|seasons|sun|orbit|equator|" AnswerCount="2" CommentCount="3" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9086" PostTypeId="1" AcceptedAnswerId="9088" CreationDate="2016-11-12T00:40:39.837" Score="3" ViewCount="2187" Body="&lt;p&gt;I went to the web site of the &lt;a href=&quot;http://w2.weather.gov/climate/&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Weather Service&lt;/a&gt; and clicked around but it was fruitless. How can I get historical weather data in the US?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to get daily high and low and precipitation for a particular weather station for time periods such as 1930 to 1940.&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2016-11-21T20:07:00.660" Title="How can I get historical weather data for the United States?" Tags="|meteorology|open-data|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9087" PostTypeId="2" ParentId="9085" CreationDate="2016-11-12T02:04:57.187" Score="1" Body="&lt;p&gt;The Earth's equator is about 0.006% closer to the sun than the Earth's mean spin axis, so the effect of proximity to the sun on daylight hours is so small that my calculator - which has a register of 10 significant figures - can't even discern any difference. A rough back of an envelope hand calculation indicates less than a millionth of a second difference in daylight hours between equator and the Earth's mean spin axis. So the effect on the weather would be indeterminate, and vastly less than caused by orbital variations, solar storms, fluctuations in solar luminosity, seasonal cloud variation, etc.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-11-12T02:04:57.187" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9088" PostTypeId="2" ParentId="9086" CreationDate="2016-11-12T02:50:11.247" Score="3" Body="&lt;p&gt;This the portal for the NOAA historical records&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ncdc.noaa.gov/cdo-web/search&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncdc.noaa.gov/cdo-web/search&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can specify what you are looking for (Summaries, or other), the time range, the area. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;They have records starting in the 1800`s to today.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2016-11-12T02:50:11.247" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9089" PostTypeId="1" AcceptedAnswerId="9090" CreationDate="2016-11-12T03:05:10.090" Score="9" ViewCount="20175" Body="&lt;p&gt;Does a fallen tree left to decay release essentially all of its stored carbon as &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; to the atmosphere? Or is the carbon uptaken by termites and bacteria, preventing its release to the atmosphere?&lt;/p&gt;&#xA;" OwnerUserId="6961" LastEditorUserId="2470" LastEditDate="2020-01-04T19:27:32.037" LastActivityDate="2020-02-14T12:20:56.313" Title="Does organic decay release the same CO2 as burning?" Tags="|carbon-cycle|co2|carbon|" AnswerCount="7" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="9090" PostTypeId="2" ParentId="9089" CreationDate="2016-11-12T09:39:56.493" Score="5" Body="&lt;p&gt;I can't quantify the answer, but intuitively, nearly all of a burning tree's carbon is converted to &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; - assuming the fire is hot enough. You are correct in assuming that termites and bacteria convert some of the carbon to other organic species, as do fungi, yeasts, moulds, and slow weathering. In addition, some of the rotting tree's carbon is converted to soluble inorganic ions, humic, fulvic and tannic acids. So no, organic decay would not yield the same &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; as burning.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This would make an interesting school or 1st-year uni science experiment. Burn some wood in a sealed environment, measure the &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; evolved, then repeat the experiment with wood in a wet organic-rich isolated biome, and compare the results. I suspect it would make for an interesting paper with potential climate change policy implications.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="2470" LastEditDate="2020-01-04T19:28:21.187" LastActivityDate="2020-01-04T19:28:21.187" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="9091" PostTypeId="2" ParentId="8267" CreationDate="2016-11-12T13:03:08.783" Score="3" Body="&lt;p&gt;What you have found there is a beautiful example of a rock which has been bored by a colony of piddocks. &#xA;Piddocks are little bivalve animals with oval shells edged with fine teeth.  They use their toothed shells to excavate burrows in rock.  The muscular part of their body, called a “foot”, grips the stone surface and helps to rotate the shell, creating a circular scouring action.   Over time and as the piddock grows, its shallow excavation gets deeper. The piddock lives inside this safe tunnel and extends a siphon beyond the edge of the tunnel, which it uses to filter food such as phytoplankton from the sea water.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Individual piddocks live for around eight years, and so some of the rocks where their colonies settle can be riddled with quite deep hopes.  Their shells are very brittle and once the animal dies the shell is quickly broken by the action of the ocean – which means that you are unlikely to find a whole piddock shell unless it’s still embedded in the stone.&#xA;But they leave examples of their handiwork on the rocks they lived on, and over time these rocks get washed up onto beaches. Below are some photographs of rocks with piddock bore holes in them. Some still have the piddocks hiding inside! And the third shows a piddock outside of its protective tunnel.  &lt;/p&gt;&#xA;" OwnerUserId="6963" LastEditorUserId="5536" LastEditDate="2016-11-12T20:52:52.867" LastActivityDate="2016-11-12T20:52:52.867" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9093" PostTypeId="1" CreationDate="2016-11-12T14:33:46.350" Score="0" ViewCount="852" Body="&lt;p&gt;&lt;em&gt;Where would you have to be for the sun to be highest overhead at noon on June 21?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the rays of the Sun are perpendicular to the Tropic of Cancer on June 21, shouldn't the Sun be overhead in this location at &lt;strong&gt;noon&lt;/strong&gt;? &lt;/p&gt;&#xA;" OwnerUserId="6965" LastActivityDate="2016-11-23T23:24:33.500" Title="Sun's Highest Point on June 21" Tags="|seasons|sun|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9094" PostTypeId="2" ParentId="9093" CreationDate="2016-11-12T17:21:39.920" Score="4" Body="&lt;p&gt;&lt;strong&gt;Well, kind of, depending on what you really mean.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We're being rather vague with our terms, and so it shouldn't be surprising if the answer doesn't meet our expectations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We could interpret all these terms to conclude that such a situation will only rarely, or even never, happen.&#xA;But allowing some reasonable latitude (pardon the pun) in our definitions, we can come up with a reasonable response of &quot;yes&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Sun can only be &quot;directly overhead&quot; of one spot at a time, where the line between the Earth's center and the sun intersects the Earth's surface. Because the Earth is spinning on its axis and also moving in its orbit,  that spot is constantly changing latitude and longitude. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Tropic of Cancer isn't a single-point &quot;location&quot; but a circle that stretches around the Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the exact moment of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Summer_solstice&quot; rel=&quot;nofollow noreferrer&quot;&gt;summer solstice&lt;/a&gt;, the Sun is directly overhead one point on the Tropic of Cancer &lt;strong&gt;&lt;em&gt;and one point only&lt;/em&gt;&lt;/strong&gt;. That point slowly spirals down through the tropics until it reaches a corresponding point on the Tropic of Capricorn at the winter solstice. And then it begins the trip back up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's what happens in the geometrically-idealized definition of &quot;directly overhead&quot;.  We can allow a small tolerance, and as the tolerance gets bigger, the spot of &quot;direct overheadness&quot; spreads out into a disk, which covers more and more of the Tropic of Cancer around the moment of the Solstice, due to the spot's E-W motion being much greater than its N-S motion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although the spot's change in latitude over time isn't linear , it's a reasonable approximation for this exercise.  The spot moves about 0.18 degrees north or south in a day, all the while circling the Earth. Around the Solstice it will move 0.09 degrees north and 0.09 south. The Sun's angular size in the sky is 0.5 degrees, so, it's reasonable to conclude that yes, the Sun is directly overhead every point of the Tropic of Cancer &lt;strong&gt;&lt;em&gt;at some time around the summer solstice&lt;/em&gt;&lt;/strong&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(The solstice does't always happen on June 21, but depending on the tolerance, some degree of direct-overheadness will be the situation  for a few days before and after the solstice).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So now, we get to your last two tricky terms: &quot;noon&quot; and &quot;June 21&quot; , which believe it or not are in conflict for this example. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a local &quot;noon&quot; (defined by when the Sun is the highest in the sky it can get) and a clock &quot;noon&quot; (defined by your time zone). Only people at lucky longitudes in their time zones get to have them coincide.  But &quot;June 21&quot; is defined by those very time zones.  And so the sun can be &quot;directly overhead&quot; at &quot;noon&quot; on June 21 only around those lucky meridians. Elsewhere the sun will be directly overhead at some time other than noon.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2016-11-23T23:24:33.500" LastActivityDate="2016-11-23T23:24:33.500" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9095" PostTypeId="2" ParentId="9089" CreationDate="2016-11-12T22:07:33.227" Score="3" Body="&lt;p&gt;The key word in your query is the word &quot;essentially&quot;. Termites and bacteria die too. So whatever carbon was initially converted from the tree into termites or bacteria ends up mostly going to &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; also. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course some carbon gets converted to carbonate and that can combine with calcium to form the mineral calcite. The tree can also get buried in mud and over eons get converted to coal or oil. &lt;/p&gt;&#xA;" OwnerUserId="4685" LastEditorUserId="2470" LastEditDate="2020-01-04T19:28:40.480" LastActivityDate="2020-01-04T19:28:40.480" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="9096" PostTypeId="2" ParentId="6916" CreationDate="2016-11-12T22:58:04.933" Score="2" Body="&lt;p&gt;There are public databases with the coastline in lon,lat format. You just need to find the point closest to your coordinates in that coastline. For that you need the formula of the distance between two lon,lat points on an ellipsoid. In this article you can find that and an idea of how to do it: &#xA;Garcia-Castellanos, D., &amp;amp; U. Lombardo, 2007. Poles of Inaccessibility: a calculation algorithm for the remotest places on Earth. Scott. Geogr. J., 123, 227-233. doi:10.1080/14702540801897809 &#xA;available here: &lt;a href=&quot;https://web.archive.org/web/20140629230429/http://cuba.ija.csic.es/~danielgc/papers/Garcia-Castellanos,%20Lombardo,%202007,%20SGJ.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://web.archive.org/web/20140629230429/http://cuba.ija.csic.es/~danielgc/papers/Garcia-Castellanos,%20Lombardo,%202007,%20SGJ.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1379" LastActivityDate="2016-11-12T22:58:04.933" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9097" PostTypeId="1" CreationDate="2016-11-13T01:49:48.877" Score="2" ViewCount="154" Body="&lt;p&gt;The diameters of Venus (7,520.8 miles) and Earth (7,917.5 miles) are comparable, but the disparity of the length of the day for each planet - as expressed in terrestrial hours - is enormous; a day on Venus lasts 2802 hours vs. an Earth day lasting 24 hours (its 116.750 times that of Earth).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can there be such a great difference when the size of the two planets is nearly the same? Does the fact that Venus’ rotation is retrograde to all of the other planets in our solar system affect the length of it's day? &lt;/p&gt;&#xA;" OwnerUserId="6905" LastEditorUserId="543" LastEditDate="2016-11-13T04:42:13.517" LastActivityDate="2017-01-03T22:05:08.367" Title="Terrestrial Day vs. Venusian Day: Why the Huge Time Difference?" Tags="|planetary-science|earth-rotation|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9098" PostTypeId="2" ParentId="9097" CreationDate="2016-11-13T10:14:08.303" Score="2" Body="&lt;p&gt;There is no reason why the day length should be the same. From the time of planetary formation, some 4.6 Bn years ago there has been some degree of slowing of day length due to tidal friction, which is much higher on Earth than on Venus, so the original contrast in day length may have been even greater than today. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are three major reasons for differencial spin rates. Firstly, the initial planetary rotation rate was a function of the net angular momentum of the planetesimals, gas, and miscellaneous debris from that part of the solar nebula from which the planet condensed (in accordance with the conservation of angular momentum). There is no reason to suppose that that the original solar nebula consisted of a nicely ordered, evenly distributed mass/velocity distribution. Rather, there is every reason to think that it was a highly chaotic heterogeneous cloud of matter undergoing gravitational mayhem - probably including large scale gravitational disruption by gas giants much closer to the sun than we see them today. From such chaos one could model almost any distribution of relative rotation speeds amongst the final planets.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly, there is strong evidence that proto-Earth collided with a 'trojan' named 'Theia', about the size of Mars, about 4.3 Bn years ago. This is the 'giant impact hypothesis', which provides a good explanation for Earth having such a large moon. We don't know the relative angular momentum of either proto-planet, their relative motions, or the angle of impact (head on? glancing?), so it is probably impossible to reconstruct the event. However, it is (relatively) easy to envisage how such an impact could radically change the Earth's angular momentum. The spin could have been hugely accelerated or decelerated according to the physics of the impact. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thirdly, Venus's relative proximity to the sun could have resulted in its undergoing rotational capture, such that eventually one face of Venus will perpetually face the sun. This gravitational locking of Venus is probably the most significant reason for its' long day. As you rightly note, the retrograde spin of Venus is curious. Therefore we may infer that Venus's spin history is more complex than we can account for by simple planetary accretion. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2016-11-13T10:22:32.217" LastActivityDate="2016-11-13T10:22:32.217" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9100" PostTypeId="1" AcceptedAnswerId="9106" CreationDate="2016-11-13T23:42:51.433" Score="4" ViewCount="213" Body="&lt;p&gt;Here, in New Zealand, we just had a 7.5 magnitude earthquake hit. Alot of people are saying that the super moon caused this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have doubts as to the super moon actually 'causing' it but could have it contributed to the earthquake due to its stronger gravitational pull?&lt;/p&gt;&#xA;" OwnerUserId="3393" LastActivityDate="2016-11-16T07:37:44.857" Title="Does the moon have any affect on earthquakes being created?" Tags="|earthquakes|" AnswerCount="2" CommentCount="0" ClosedDate="2016-11-16T05:33:32.603" ContentLicense="CC BY-SA 3.0" />
  <row Id="9101" PostTypeId="2" ParentId="9085" CreationDate="2016-11-13T23:48:38.033" Score="1" Body="&lt;p&gt;No.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a difference in daylight according to latitude, but it is not because of proximity to the sun, and nor is there a significant difference in the total number of daylight hours in a year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What &lt;em&gt;is&lt;/em&gt; different is that at the equator, the length of the day is nearly equal all year round. The higher your latitude (the further from the equator and the nearer to the poles) the more difference there is in the length of the day between summer and winter - with the extreme at the poles of six months of light or darkness.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2016-11-13T23:48:38.033" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9102" PostTypeId="1" CreationDate="2016-11-14T00:55:20.407" Score="3" ViewCount="236" Body="&lt;p&gt;Is there a widely accepted model for the &lt;a href=&quot;https://en.wikipedia.org/wiki/Supercontinent#Supercontinent_cycles&quot; rel=&quot;nofollow noreferrer&quot;&gt;supercontinent cycles&lt;/a&gt; ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the novice point of view, it is not obvious why the continents would be fragmented all over the earth as now, but 300 millions years ago it was the opposite, they were assembled into one single supercontinent : the &lt;a href=&quot;https://en.wikipedia.org/wiki/Pangaea&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pangaea&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also this &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_supercontinents&quot; rel=&quot;nofollow noreferrer&quot;&gt;list of supercontinents&lt;/a&gt; suggests it never stopped oscillating between fragmented and concentrated during earth's history, so that on the long term, the continents don't appear following a random law for their relative position (as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Plate_tectonics#Driving_forces_of_plate_motion&quot; rel=&quot;nofollow noreferrer&quot;&gt;plate tectonics driving forces model would suggest&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So is there an explanation for that, or is it mainly observational with no trustful model behind this oscillation of the lands concentration, from one extremum to the other ?&lt;/p&gt;&#xA;" OwnerUserId="6972" LastEditorUserId="6972" LastEditDate="2016-11-14T07:28:28.767" LastActivityDate="2016-11-14T07:28:28.767" Title="Pangaea, supercontinent formation and fragmentation" Tags="|plate-tectonics|earth-history|" AnswerCount="0" CommentCount="0" ClosedDate="2016-11-18T13:00:26.700" ContentLicense="CC BY-SA 3.0" />
  <row Id="9103" PostTypeId="1" AcceptedAnswerId="9128" CreationDate="2016-11-14T02:45:38.290" Score="16" ViewCount="1680" Body="&lt;p&gt;The &lt;a href=&quot;https://xkcd.com/1732/&quot; rel=&quot;nofollow noreferrer&quot;&gt;xkcd &quot;Earth Temperature Timeline&quot;&lt;/a&gt; depicts the global average temperature during the past 20,000 years, based on the known data. We &lt;a href=&quot;https://earthscience.stackexchange.com/questions/8746/is-this-xkcd-comic-an-accurate-timeline-of-the-earths-average-temperature&quot;&gt;already have a question&lt;/a&gt; about the chart's general accuracy, but I have a more specific question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The chart says that multi-decade, multi-degree global climate shifts should be easily visible, and the fact that the chart is smooth and shows no such variances until it suddenly jumps in the past hundred years gives the graphic its visceral power.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But then, I found out about a myriad of known &lt;a href=&quot;https://en.wikipedia.org/wiki/Abrupt_climate_change&quot; rel=&quot;nofollow noreferrer&quot;&gt;abrupt climate change&lt;/a&gt; events, such as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Younger_Dryas&quot; rel=&quot;nofollow noreferrer&quot;&gt;Younger Dryas&lt;/a&gt; 12,000 years ago, during which the temperature of large parts of the northern hemisphere decreased in temperature by 2 to 6 degrees Celsius over mere decades, then stayed that way for a millennium. Yet no rapid shifts like this are visible in the xkcd chart. This seems to imply that either&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;the temperature shift in much of the northern hemisphere during the Younger Dryas was exactly counterbalanced by concurrent temperature shifts in the rest of the world so that the global average looks virtually the same; or&lt;/li&gt;&#xA;&lt;li&gt;the xkcd chart omits important details; or&lt;/li&gt;&#xA;&lt;li&gt;there are major contradictions in climate data from various sources.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Are one of these options correct, or is something else going on?&lt;/p&gt;&#xA;" OwnerUserId="6973" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2020-01-24T23:45:13.533" Title="How do the known abrupt climate change events fit into the xkcd Earth temperature timeline?" Tags="|climate-change|younger-dryas|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9104" PostTypeId="2" ParentId="9100" CreationDate="2016-11-14T05:43:21.540" Score="4" Body="&lt;p&gt;The forces involved in the New Zealand earthquake are not amenable to precise evaluation - at least not without detailed geotechnical evaluation, but we can use the &lt;em&gt;peak ground acceleration&lt;/em&gt; as a proxy. For a magnitude 7.5 earthquake the peak ground acceleration is about 0.4g. Compare this to the normal moon's gravitational acceleration on Earth's surface of about 3.318 E-5 g. 'Super-moons' are about 16000 km closer than usual, yielding a gravitational acceleration of 3.783 E-5 g. Therefore the &lt;em&gt;differential&lt;/em&gt; gravitational acceleration of a super-moon, compared to a normal moon, is about 4.65 E-6 g. Or to put it another way, the effect of a super-moon is to create about a 0.001% of the acceleration (and hence force) required for the accumulated strain energy to overcome friction, and hence cause the earthquake. This assumes that &lt;em&gt;all&lt;/em&gt; of the moon's gravity was aligned in such a way as to exacerbate strain along the slip plane - which is never going to be the case. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suppose that one could argue that the miniscule gravitational force of a super-moon could have been the 'straw that broke the camel's back', but the accumulated strain energy in the ground must have been so great that the earthquake was about to happen anyway, with or without the moon's gravity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Afterthought: With the boot on the other foot: The Earth's much larger gravitation has an effect on the Moon. There are moon tides which cause regular, small but measurable moon-quakes. See Moritz and Melchior (2013), &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/SP035p0047/summary&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Tidal Interactions in the Earth-Moon System&lt;/em&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="6093" LastEditDate="2016-11-16T07:37:44.857" LastActivityDate="2016-11-16T07:37:44.857" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9105" PostTypeId="2" ParentId="6916" CreationDate="2016-11-14T09:24:11.333" Score="0" Body="&lt;p&gt;Well if you can describe the lake perimeter by a set of latitudes and longitudes then you can calculate the great circles of those points and the position of interest. The minimum value will correspond to the distance between the generic point and the closest one on the coast.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.movable-type.co.uk/scripts/latlong.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;This website&lt;/a&gt; describes how you can calculate the great circles.&lt;/p&gt;&#xA;" OwnerUserId="6974" LastActivityDate="2016-11-14T09:24:11.333" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9106" PostTypeId="2" ParentId="9100" CreationDate="2016-11-14T10:20:49.333" Score="3" Body="&lt;p&gt;Keep in mind that this &amp;quot;special&amp;quot; &amp;quot;supermoon&amp;quot; is only about 0.5% closer this month than it was last month, or will be next month.  And now is only 0.1% closer away at last year's minimum (and in fact, the minimum distance each year of the past 20 is only separated by 0.3% variation)&lt;br /&gt;&#xA;Makes it a little less exciting, eh? [source for data: &lt;a href=&quot;https://www.timeanddate.com/astronomy/moon/distance.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;timeanddate.com&lt;/a&gt;]&lt;/p&gt;&#xA;&lt;p&gt;And likewise &lt;a href=&quot;http://www.space.com/21660-supermoon-rises-sunday-full-moon.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; article from space.com suggests that tide differences between a supermoon and a typical full moon are likely fairly small.&lt;/p&gt;&#xA;&lt;p&gt;I'm certainly no expert on any of these topics in question, and am hopeful we'll see more precise calculations and details from someone more plugged into these fields.  But that information at least suggests that &lt;strong&gt;it is dubious to credit the earthquakes to the exceptional proximity of THIS particular &amp;quot;supermoon&amp;quot;.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now do supermoons, or for that matter, full moons in general, cause earthquakes?  I have no expertise in any of these topics areas (you can see that with my &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9080/are-there-any-seasonal-or-diurnal-trends-in-earthquakes&quot;&gt;related question&lt;/a&gt; that I happened to post earlier this week asking about seasonal\temperature influences).  But I decided to do a quick rough study because it was an interesting question that I had as well.&lt;/p&gt;&#xA;&lt;p&gt;Applying the &lt;a href=&quot;http://www.emsc-csem.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;EMSC-CSEM&lt;/a&gt; earthquake search, I found that 7.9 and greater magnitude quakes gave me a good manageable set to work with from their database (dating to October 2004).  I did not look at potential results when choosing the set size.  But found it was a fair size to put together, and would at least give a potential taste.&lt;/p&gt;&#xA;&lt;p&gt;So here are all &amp;gt;= 7.9s in the past 12ish years, as well as their moon phase and earth-moon distance (which appears to vary from about 356500-407000 km, completing 1-2 cycles a year):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Mag | Moon | Moon Dist | Event&lt;/li&gt;&#xA;&lt;li&gt;9.3 | 100% | 405266 km | 2004 Indian Ocean Earthquake (12-26-04)&lt;/li&gt;&#xA;&lt;li&gt;9.0 | 33.% | 395992 km | 2011 Japan Earthquake (03-11-11)&lt;/li&gt;&#xA;&lt;li&gt;8.8 | 97.% | 357971 km | 2010 Chile Earthquake (02-27-10)&lt;/li&gt;&#xA;&lt;li&gt;8.6 | 92.% | 380842 km | 2005 Sumatra Earthquake (03-28-05)&lt;/li&gt;&#xA;&lt;li&gt;8.4 | 01.% | 400497 km | 2007 Sumatra Earthquake (09-12-07)&lt;/li&gt;&#xA;&lt;li&gt;8.4 | 72.% | 368806 km | 2012 Sumatra Earthquake (04-11-12)&lt;/li&gt;&#xA;&lt;li&gt;8.3 | 25.% | 405266 km | 2006 Kuril Islands [NE of Japan] Earthquake (11-15-06)&lt;/li&gt;&#xA;&lt;li&gt;8.3 | 99.% | 361064 km | 2013 Sea Okhotsk Earthquake [NE of Japan] Earthquake (05-24-13)&lt;/li&gt;&#xA;&lt;li&gt;8.3 | 12.% | 404185 km | 2015 Chile Earthquake (09-16-25)&lt;/li&gt;&#xA;&lt;li&gt;8.2 | 35.% | 400532 km | 2007 Kuril Islands [NE of Japan] Earthquake (01-13-07)&lt;/li&gt;&#xA;&lt;li&gt;8.1 | 99.% | 405537 km | 2007 Solomon Islands Earthquake (04-01-07)&lt;/li&gt;&#xA;&lt;li&gt;8.1 | 81.% | 403548 km | 2009 Samoa Islands Earthquake (09-29-09)&lt;/li&gt;&#xA;&lt;li&gt;8.1 | 06.% | 381485 km | 2014 Chile Earthquake (04-01-14)&lt;/li&gt;&#xA;&lt;li&gt;7.9 | 09.% | 399204 km | 2007 Peru Earthquake (08-15-07)&lt;/li&gt;&#xA;&lt;li&gt;7.9 | 51.% | 382561 km | 2008 China Earthquake (05-12-08)&lt;/li&gt;&#xA;&lt;li&gt;7.9 | 41.% | 402219 km | 2009 Tonga Earthquake (03-19-09)&lt;/li&gt;&#xA;&lt;li&gt;7.9 | 33.% | 395899 km | 2011 Japan Earthquake Aftershock (03-11-11)&lt;/li&gt;&#xA;&lt;li&gt;7.9 | 23.% | 365928 km | 2013 Solomon Islands Earthquake (02-06-13)&lt;/li&gt;&#xA;&lt;li&gt;7.9 | 12.% | 390858 km | 2014 Alaska (Aleutians) Earthquake (06-23-14)&lt;/li&gt;&#xA;&lt;li&gt;7.9 | 98.% | 357791 km | 2016 New Zealand Earthquake (focus of this post)&lt;br /&gt;&#xA;(Moon phases from &lt;a href=&quot;http://aa.usno.navy.mil/data/docs/MoonFraction.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;USNO&lt;/a&gt;, distances from &lt;a href=&quot;http://www.satellite-calculations.com/Satellite/suncalc.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;satellite-calculations.com&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Breaking it down (after removing the Japan aftershock), seems a bit of a predilection for full moons:&lt;br /&gt;&#xA;(6 of the 19 were 90+% full).&lt;br /&gt;&#xA;And just maybe a slight increase near new moon as well, which would match the way that earlier article described that tides work:&lt;br /&gt;&#xA;(5 of 19 &amp;lt;= 12%).&lt;/p&gt;&#xA;&lt;p&gt;Here's a histogram of the spread [made at &lt;a href=&quot;http://www.wessa.net/rwasp_histogram.wasp&quot; rel=&quot;nofollow noreferrer&quot;&gt;wessa.net&lt;/a&gt;]:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GMQpn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GMQpn.png&quot; alt=&quot;Distribution&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But it doesn't seem there's as much of a trend in distances:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Xe7LM.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Xe7LM.png&quot; alt=&quot;Distance and Phase&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It's almost certainly not enough data to draw a rock solid conclusion, but interesting that it seems hints at favoring full moons.  I'm not sure what statistical calculations to do to prove it... the mean is only 51%, so it'd need more than just a mean test to prove that it's bi-modal (favoring full/new moons).&lt;br /&gt;&#xA;But this quick look certainly seems to suggest at least that there isn't obvious trends in earth-moon distance impacting earthquakes (R^2 = 0.14).&lt;/p&gt;&#xA;&lt;p&gt;The real connections may be much more complex (varying by location\geology, only affecting certain types of earthquakes, more significant for weaker earthquakes, etc).  But hopefully this try using big data from about the last decade is at least a help!&lt;/p&gt;&#xA;&lt;p&gt;Hope the cleanup goes well AnonDCX!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-11-14T11:16:55.657" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9107" PostTypeId="1" CreationDate="2016-11-14T16:05:02.780" Score="2" ViewCount="72" Body="&lt;p&gt;I have been studying the Humber, Gander and Terra Nova rivers in Newfoundland. I have been given a table of discharges, and for the peak discharges I see:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Gander: around April and May (rougly from day 101 to day 141 if day 1 = January 1st)&lt;/li&gt;&#xA;&lt;li&gt;Humber slightly after Gander&lt;/li&gt;&#xA;&lt;li&gt;Terra Nova has a peak discharge around March, before the others&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;For the &lt;em&gt;minimum&lt;/em&gt; discharges I see:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Terra Nova: around day 201 of the year&lt;/li&gt;&#xA;&lt;li&gt;Gander: around day 211 (June/July)&lt;/li&gt;&#xA;&lt;li&gt;Humber: January and February and then again slightly after Gander.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So clearly climate, both the precipitation of rain and snow affects this discharge but what is the cause behind the different times in max and min discharge of these three rivers?&lt;/p&gt;&#xA;" OwnerUserId="6975" LastEditorUserId="10681" LastEditDate="2017-09-14T03:11:55.820" LastActivityDate="2022-08-31T06:17:40.530" Title="Different peak and mininum discharge times for Newfoundland rivers" Tags="|hydrology|rivers|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9108" PostTypeId="1" CreationDate="2016-11-14T16:31:02.553" Score="4" ViewCount="110" Body="&lt;p&gt;I'm dealing with NO2 column density of troposphere, and my data source is &lt;a href=&quot;http://www.temis.nl/airpollution/no2col/no2regioomimonth_v2.php&quot; rel=&quot;noreferrer&quot;&gt;TEMIS&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The NO2 level3 data can be derived from the original information of OMI instrument.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have downloaded two types of data, &lt;em&gt;.grd&lt;/em&gt; and &lt;em&gt;.kml&lt;/em&gt; for the same month. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data I have downloaded are uploaded here&lt;a href=&quot;https://drive.google.com/file/d/0B7FE0kxAL8kQV3FEQlhTa0N6Wmc/view?usp=sharing&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;https://drive.google.com/file/d/0B7FE0kxAL8kQRE53UDRrRm9ISFk/view?usp=sharing&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;KML data&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;I open it in Google Earth, the figure shows like this:   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WnZj8.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WnZj8.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can see the data range of NO2 trop. column is 0~20 which are idential to the templete figure on the website. &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;GRD data&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;I have not found any detailed information about this data. &#xA;In the contents of it, &lt;code&gt;-999&lt;/code&gt; is deemed as no_data place.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I use python to read and plot the spatial distribution. &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;filename  = './CH2O-NO2/no2_201306.grd'&#xA;def read_grd(filename):&#xA;    ncols     = np.array(linecache.getline(filename, 1)[6:10]).astype(float)&#xA;    nrows     = np.array(linecache.getline(filename, 2)[6:10]).astype(float)&#xA;    xllcorner = np.array(linecache.getline(filename, 3)[10:14]).astype(float)&#xA;    yllcorner = np.array(linecache.getline(filename, 4)[10:14]).astype(float)&#xA;    cellsize  = np.array(linecache.getline(filename, 5)[9:14]).astype(float)&#xA;    nan_value = np.array(linecache.getline(filename, 6)[13:17]).astype(float)&#xA;    longitude = xllcorner + cellsize * np.arange(ncols)&#xA;    latitude = yllcorner + cellsize * np.arange(nrows)&#xA;    value = np.loadtxt(filename, skiprows=7)&#xA;    value = value[::-1]&#xA;    return value, longitude, latitude, nan_value&#xA;&#xA;no2,lon_no2, lat_no2, nan_value = read_grd(filename)&#xA;no2[no2 == nan_value] = np.nan&#xA;&#xA;def isnt_NaN(num):&#xA;    return num == num&#xA;&#xA;no2[isnt_NaN(no2)].max()&#xA;&amp;gt; 9999.0&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It seems that the high value in &lt;strong&gt;grd&lt;/strong&gt; format data are out of the regular condition which can be learned from previous resarch (Hot spots of NO2 column are about 15~20 10^15 molec/cm2).  &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Does anyone familiar with the OMI-NO2 data? I don't know how to deal with the irregular value which are way too higher than realistic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BAwKL.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BAwKL.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5214" LastActivityDate="2017-01-16T05:40:48.100" Title="The higher value range for the same satellite product (NO2_OMI_TEMIS)" Tags="|atmosphere|remote-sensing|air-pollution|atmospheric-chemistry|satellites|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9110" PostTypeId="2" ParentId="9107" CreationDate="2016-11-15T12:56:05.483" Score="2" Body="&lt;p&gt;All of the following parameters would affect seasonal maximum and minimum flow times. Differences between the river basins:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Size of drainage area&lt;/li&gt;&#xA;&lt;li&gt;Average relief of topography within the drainage area&lt;/li&gt;&#xA;&lt;li&gt;Amount of groundwater entering the river (near max)&lt;/li&gt;&#xA;&lt;li&gt;Amount of water leaking into the local water table (near min),&lt;/li&gt;&#xA;&lt;li&gt;Underlying differences in geology of the river basins&lt;/li&gt;&#xA;&lt;li&gt;Water usage from each river&lt;/li&gt;&#xA;&lt;li&gt;localized weather patterns&lt;/li&gt;&#xA;&lt;li&gt;Sun exposure (for snow melt)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Careful and detailed geological and hydro-geological study of each river basin would need to be performed to determine exact cause of differences in timing of max and min flow times.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="21672" LastEditDate="2022-08-31T06:17:40.530" LastActivityDate="2022-08-31T06:17:40.530" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="9111" PostTypeId="1" AcceptedAnswerId="9127" CreationDate="2016-11-15T15:22:21.843" Score="1" ViewCount="342" Body="&lt;p&gt;I am working with SPI (Standardized Precipitation Index) and in particular I am interested in obtaining the seasonal mean observation over a period of 40 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The meteorological season I am considering is Winter and therefore the months of December-January-February.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The point is that for each location and for time scale I am using, the overall seasonal SPI winter mean should = ~0.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is that possible?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am expecting that the annual SPI averages would be = 0, because of the definition of SPI, but not for the overall seasonal mean.&lt;/p&gt;&#xA;" OwnerUserId="6978" LastEditorUserId="5536" LastEditDate="2016-11-15T15:57:36.350" LastActivityDate="2018-04-16T11:49:26.150" Title="SPI (Standardized Precipitation Index) for 40 years seasonal mean" Tags="|precipitation|drought|data-analysis|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9112" PostTypeId="1" CreationDate="2016-11-15T20:27:06.460" Score="3" ViewCount="896" Body="&lt;p&gt;In many areas of South America, Africa, India and Southeast Asia, &quot;slash-and-burn&quot; agriculture is employed whereby every year the stubble from the previous year is burned along with other live cuttings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In North America, this does not seem to have ever happened. It is true that in New England (where I am from) the old-time farmers cut down all the trees and burned them to get pot ash, but this seems to have been a one time event. Once land was cleared of trees, it was not burned over and over again. Also, in many cases land was cleared without burning at all, the trees and stumps simply being hauled away.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there some difference in climate that results in tropical areas being subjected to repeated annual burnings whereas lands in North America are not? What causes the difference?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastEditorUserId="6298" LastEditDate="2016-11-16T01:48:26.473" LastActivityDate="2016-11-27T15:39:53.640" Title="Lack of annual slash-and-burn in North America?" Tags="|climate|agriculture|ecology|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9113" PostTypeId="1" AcceptedAnswerId="9174" CreationDate="2016-11-16T02:18:34.157" Score="2" ViewCount="211" Body="&lt;p&gt;I was reading the paper &lt;a href=&quot;http://ams.confex.com/ams/pdfpapers/47601.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Washington DC tornado of 24 september 2001: pre-storm environment and radar perspectives&lt;/a&gt; which had this passage: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;At 1200 UTC 24 September 2001, at 500 hPa a deep (560 [gpdm]) cut-off extratropical low (midlatitude cyclone that is cut off from the jet stream) was located over Wisconsin with a central core temperature of -20 C.&quot; (). &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Is 560 dm deep for that part of the country and that time of year? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have revised the question based on suggestions fomr the comments.&lt;/p&gt;&#xA;" OwnerUserId="6816" LastEditorUserId="6816" LastEditDate="2016-11-23T05:44:53.550" LastActivityDate="2016-11-23T05:44:53.550" Title="With respect to latitude and time of year, what geopotential heights are associated with low pressure systems on the North American landmass?" Tags="|meteorology|barometric-pressure|troposphere|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9115" PostTypeId="2" ParentId="9108" CreationDate="2016-11-16T03:07:06.180" Score="2" Body="&lt;p&gt;It seems that you are concerned that your values in the data go above the max value on the color bar shown in the kml file.  I wouldn't worry about that.  You are using the &quot;level 3&quot; monthly average product, which by definition is highly quality controlled.  For most of the globe, typical values will vary between 1 x 10^14 and 5 x 10^15 molec/cm2.  Values over 20 x 10^15 molec/cm2 only occur in highly polluted areas.  Very large values in the OMI NO2 product are realistic, especially in SE Asia, where the largest NO2 columns are obtained.  I have even seen values over 1 x 10^17 on occasion.  As the signal gets larger, there is actually more confidence in the retrieval.  Really it's the low values (e.g. less than 8 x 10^14 molec/cm2) that you should treat cautiously, as anything lower than that could be &quot;noise&quot;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to show the variance of values (which can span 4 orders of magnitude) across the whole globe, the color scale chosen works well.  Note that the color bar is a logarithmic scale, which helps give definition to the plots in the regions with typical values.  You could rewrite the kml file though, and pick a different max value, if you are interested in better plots of southeast Asia.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are interested in learning more about the product, I highly suggest you see &lt;a href=&quot;http://atmos-meas-tech.net/4/1905/2011/amt-4-1905-2011.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Boersma (2011)&lt;/a&gt; and also refer to the &lt;a href=&quot;http://www.temis.nl/docs/OMI_NO2_HE5_2.0_2011.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;user manual&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2017-01-16T05:40:48.100" LastActivityDate="2017-01-16T05:40:48.100" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9116" PostTypeId="1" AcceptedAnswerId="9117" CreationDate="2016-11-16T06:52:53.290" Score="0" ViewCount="403" Body="&lt;p&gt;Assuming I have data of BOD, COD and water discharge. How do I calculate the O2 requirement?&lt;/p&gt;&#xA;" OwnerUserId="6980" LastActivityDate="2016-11-16T07:16:35.700" Title="How do I calculate Oxygen requirement in an aerobic waste water pond?" Tags="|water|" AnswerCount="1" CommentCount="2" ClosedDate="2016-11-17T09:08:23.287" ContentLicense="CC BY-SA 3.0" />
  <row Id="9117" PostTypeId="2" ParentId="9116" CreationDate="2016-11-16T07:16:35.700" Score="0" Body="&lt;p&gt;you can actually calculate the theoretical oxygen requirement using the following formula:&#xA;O2 req (kgO2/d) = [Q * (S0-S) / (BOD5/BODL)]/ 1000&#xA;Where:&#xA;Q= flowrate m3/day&#xA;S0= infulent BOD/COD concentration (mg/L)&#xA;S= efulent BOD/COD concentration (mg/L)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;FYI Successful decreasing of BOD and COD can be obtain by using high volume Oxygen Generator such as &lt;a href=&quot;http://www.isw.co.id/turbo-pro-aerator-eng&quot; rel=&quot;nofollow noreferrer&quot;&gt;Submersible Aeration&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="6981" LastActivityDate="2016-11-16T07:16:35.700" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9119" PostTypeId="1" AcceptedAnswerId="9120" CreationDate="2016-11-16T17:31:51.580" Score="10" ViewCount="646" Body="&lt;p&gt;In this image from 2004 in Afghanistan Kandahar region many small craters are seen. What are they?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DsI10.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DsI10.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2016-11-16T19:28:46.517" Title="Strange craters in Afghanistan" Tags="|geomorphology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9120" PostTypeId="2" ParentId="9119" CreationDate="2016-11-16T19:28:46.517" Score="12" Body="&lt;p&gt;These are qanats, a type of antique drainage system common in arid climate regions of the Middle East, particularly in Iran (as mentioned by @Spencer @Winwaed). Some of those are still in use for storage because of lower underground temperature or to access the underground water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the picture posted by OP, it further make sense since the underground channels follow linear paths near, around and crossing the small stream, thus providing a remote access to water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is an oblique picture showing the qanats of Bam in Iran (Higher resolution available at the &lt;strong&gt;source&lt;/strong&gt; &lt;a href=&quot;http://whc.unesco.org/en/documents/141554&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2ijVB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2ijVB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2016-11-16T19:28:46.517" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9122" PostTypeId="1" AcceptedAnswerId="9123" CreationDate="2016-11-17T09:49:28.580" Score="4" ViewCount="308" Body="&lt;p&gt;The post &lt;a href=&quot;http://what-if.xkcd.com/16/&quot; rel=&quot;noreferrer&quot;&gt;Lightning&lt;/a&gt; mentions about &quot;the core of a lightning bolt&quot;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The core of a lightning bolt is a &lt;a href=&quot;http://www.agu.org/pubs/crossref/1968/JB073i006p01889.shtml&quot; rel=&quot;noreferrer&quot;&gt;few centimeters in diameter&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I couldn't find any article discussing about this. The reference link has been changed, so I couldn't read the original post. So what is it?&lt;/p&gt;&#xA;" OwnerUserId="4945" LastEditorUserId="4945" LastEditDate="2016-11-17T10:10:11.130" LastActivityDate="2016-11-17T19:38:22.100" Title="What is the core of the lightning?" Tags="|lightning|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9123" PostTypeId="2" ParentId="9122" CreationDate="2016-11-17T17:46:51.773" Score="5" Body="&lt;p&gt;I found the paper you initially referred to here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/JB073i006p01889/full&quot; rel=&quot;noreferrer&quot;&gt;http://onlinelibrary.wiley.com/doi/10.1029/JB073i006p01889/full&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;based on the hyperlink by the xkcd webpage you referred&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.agu.org/pubs/crossref/1968/JB073i006p01889.shtml&quot; rel=&quot;noreferrer&quot;&gt;http://www.agu.org/pubs/crossref/1968/JB073i006p01889.shtml&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The full reference for this paper is: Oetzel, G. N. (1968), Computation of the diameter of a lightning return stroke, J. Geophys. Res., 73(6), 1889–1896, &lt;a href=&quot;http://dx.doi.org/10.1029/JB073i006p01889&quot; rel=&quot;noreferrer&quot;&gt;doi:10.1029/JB073i006p01889&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the abstract:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The diameter of a first return stroke is found to lie in the range &lt;strong&gt;1–4 cm&lt;/strong&gt;. Subsequent return strokes are smaller, with diameters in the range &lt;strong&gt;0.2–0.5 cm&lt;/strong&gt;. In many cases, strokes to towers have shown evidence of the smaller strokes occurring alone. These are explained as strokes initiated by an upward leader.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This paper is quite old - but is relevant nevertheless.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A more recent paper review the physics of lightning in this review paper, titled 'The Physics of lightning' by &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S037015731300375X&quot; rel=&quot;noreferrer&quot;&gt;Dwyer and Uman (2014)&lt;/a&gt;. They present the various steps implied when a lightning form, illustrated by this illustration &lt;a href=&quot;https://i.stack.imgur.com/9mVGG.jpg&quot; rel=&quot;noreferrer&quot;&gt;(Figure 1)&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/9mVGG.jpg&quot; alt=&quot;Fig. 1.3 in [Dwyer and Uman (2014)&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically, there is several stages when a lightning strike. There is the stepped leader component, that somewhat lead the way for the exchanges that will follow. In the figure, we notice the positive and negative signs (+ / -) and how they change position depending on the discharge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The stepped leader can be followed by return strikes and so on. In this paper they mention diameters for the stepped leader, which may appear to be much larger than the return stroke, such as in the range of one to ten meter in diameter:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The luminous diameter of the stepped leader has been measured photographically to be between 1 and 10 m. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But - this is by using photography - yet the core of the lightning at the center (the core) seem to be a few centimeter in diameter:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It is thought, however, that most of the stepped-leader current flows down a narrow conducting core a few centimeters in diameter at the center of the observed leader. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So in the end both papers tend toward similar centimeter-scale measurements for the lightning core.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The core: aforementioned literature refer to the component of the actual lightning as a 'current carrying core' surrounded by a corona sheath. The sheath is what appear to be 1 to 10 m in diameter, where the actual 'electricity channel' is centimeter wide; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;so this core as the centimeter wide channel is the electron pathway.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastEditorUserId="1411" LastEditDate="2016-11-17T19:38:22.100" LastActivityDate="2016-11-17T19:38:22.100" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9124" PostTypeId="1" AcceptedAnswerId="9126" CreationDate="2016-11-17T18:18:43.183" Score="0" ViewCount="368" Body="&lt;p&gt;Carbon Credits are a weird thing. Businesses can buy and sell them, and having enough carbon credits to offset your CO2 output suddenly makes you a Green Business. That being said, who issues Carbon Credits, and on what authority? Is a Carbon Credit a promise to remove an amount of CO2 from the atmosphere? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Last I checked that was a massively expensive technology still in it's infancy, but Carbon Credits have been around for quite some time.  Does it work like a Futures market (&quot;When the tech becomes available I promise to remove 30 bln tons of C02&quot;)?&lt;/p&gt;&#xA;" OwnerUserId="5673" LastEditorUserId="6703" LastEditDate="2016-11-17T18:57:47.477" LastActivityDate="2016-11-17T18:57:47.477" Title="On what authority are carbon credits issued?" Tags="|climate-change|" AnswerCount="1" CommentCount="2" ClosedDate="2016-11-20T09:51:35.950" ContentLicense="CC BY-SA 3.0" />
  <row Id="9125" PostTypeId="2" ParentId="9112" CreationDate="2016-11-17T18:36:55.290" Score="1" Body="&lt;h1&gt;Dry season&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;It is easy to burn things in the dry season, not so much where it is wet. Eastern North America generally qualifies as wet, certainly in the winter, less so in the summer. This isn't to say that you CAN'T do slash and burn where it is wet, since it is done in rainy Papua New Guinea an the Amazon, but it makes more sense as a strategy when there is a clear rainy and dry season. A forest or scrubland area will be cut in the wet season, allowed to dry in the dry season, and then burned, returning valuable nutrients to the soil. The soil can then be farmed for several years without needing further nutrients. The burning during dry is key, because it allows the burning to be done between two growing seasons (the wet season). In Eastern North America, if you tried to burning during the dry season (summer), you would lose that growing season, and have to find another source of food that year. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other side to the dry season is the wet season. Seasonal climates will almost all see much more rain in at least one month than anywhere in the eastern US, which has remarkably stable precipitation all year. Therefore, the washing of nutrients out of the soil happens more quickly in the tropics. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Soil quality&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Many places where slash and burn agriculture are prevalent had poor soil quality. Tropical environments tend to have more leached soils due to heavy seasonal rains (or heavy year-round rains). That means that burning is an effective way to add soil nutrients. Areas brought under cultivation from forest-land in Northern Europe have remained productive under cultivation for at least 2000 years (in the case of northern France and England) due to the fertile soil layer. I suspect Eastern American soils have similar vitality.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rainforest, on the other hand, retains almost no minerals and can be exhausted quickly. The only way to effectively farm is to cut down and burn the minerals in the living plants and trees to return them to the soil. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Leguminious plants&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;This is a little more theory than fact, but in the tropics, there are many leguminous trees, while in the northern latitudes there are many leguminous ground plants. African savannah-forests are dominated by acacia, mopane, and miombo. These are all leguminous trees that add nitrogen to the soil. No comparable array of dominant tree species are available in the northern latitudes. In America and Europe, soil fertility was traditionally restored with vetch, clover, alfalfa, or (nowadays) soybeans. Those are single season plants; in the case of clover and vetch the can be grown as a meadow in a year or two of fallow. The trees in the tropics, on the other hand, need a longer time to establish. Therefore, it makes relatively more sense to do a yearly fallow rotation in the northern latitudes, and a slash and burn many-year rotation in the tropics. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-11-17T18:36:55.290" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9126" PostTypeId="2" ParentId="9124" CreationDate="2016-11-17T18:47:24.743" Score="1" Body="&lt;p&gt;Carbon credit accreditation is a process done by &lt;a href=&quot;http://www.carbonneutral.com/resource-hub/carbon-offsetting-explained/carbon-offset-standards&quot; rel=&quot;nofollow noreferrer&quot;&gt;independent accrediting agencies&lt;/a&gt;. It is comparable to the way that universities are accredited by various agencies saying that their degrees are legit. You sign up to do a project to reduce carbon output, and then the accrediting agency confirms that you did just that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Carbon offsetting isn't a future's market, it is a (financial) commitment to a project right now that is dedicated to lowering greenhouse gasses. Here is a list of &lt;a href=&quot;http://www.carbonneutral.com/resource-hub/carbon-offsetting-explained/project-types&quot; rel=&quot;nofollow noreferrer&quot;&gt;potential projects&lt;/a&gt;, and here is a map showing projects &lt;a href=&quot;http://www.naturalcapitalpartners.com/projects&quot; rel=&quot;nofollow noreferrer&quot;&gt;in progress&lt;/a&gt; with a certain company. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm actually really glad you asked this question, because I just assumed that carbon offsets were effective proven means, like planting trees. But looking at some of these projects is bringing up some doubt in my mind. I don't see how burning methane into CO$_2$ is doing anything except turning a larger short-term problem into a smaller long-term problem. Or how to measure the exact number of tons of carbon you are saving by changing domestic behavior.&lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-11-17T18:47:24.743" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="9127" PostTypeId="2" ParentId="9111" CreationDate="2016-11-17T19:07:08.810" Score="3" Body="&lt;p&gt;The SPI statistic can be considered a standard normally distributed random variable $SPI \sim N(0,1)$. Thus the expected value, or mean, of the SPI statistic is $0$, and its standard deviation and variance are $1$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the mean of the distribution is zero, then by the central limit theorem, you would expect that the limit of your sample mean (the mean of ~40 years of data) would approach zero as your sample got larger. So yes, it is both possible and expected. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What may be causing your confusion is that SPI can be calculated for different time sets. If you are analyzing month by month, then I would assume that your dataset is divided by month. In that case, the SPI is calculated individually for each month, so that the mean of any month or set of months over many years would tend to zero, as per the last paragraph. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It would not make sense to calculate a monthly SPI from a 12-month mean divided by 12 (to give you a mean per month on an annual basis) In seasonal wet-dry climates you would have massively negative SPI value in the dry season, and highly positive numbers in the wet season. The monthly means are individually given an SPI statistic to allow apples-to-apples comparisons with the same month in other years.&lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-11-17T19:07:08.810" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="9128" PostTypeId="2" ParentId="9103" CreationDate="2016-11-17T20:03:24.813" Score="10" Body="&lt;p&gt;The apparent contradiction comes primarily from #1 but #2 also pays a small role here...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Temperature decreases during the Younger Dryas greater than $2^{\circ}$C are believed to have occurred almost exclusively above $30^{\circ}$N in latitude. The bulk of the tropics are thought to have been relatively stable during this time and the southern polar region showed slight warming. Additionally, global temperature averages are generally weighted by area and only one fourth of the earths surface lies between $30^{\circ}$N and the North Pole. All this combines to produce what is thought to be around 0.6$^{\circ}$C of global cooling at the start of the Younger Dryas (&lt;a href=&quot;http://people.oregonstate.edu/~carlsand/carlson_encyclopedia_Quat_2013_YD.pdf&quot; rel=&quot;noreferrer&quot;&gt;Carlson, 2013&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Randall does cite several sources in the top right of his graphic but Shakun et al. (2012) is the only one that presents meaningful temperature data during the Younger Dryas. And in fact, the comic's proxy data (dashed) temperature curve closely matches the temperature curve presented in this article over this period (curve &lt;strong&gt;d&lt;/strong&gt; in the figure below).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fGGWC.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fGGWC.jpg&quot; alt=&quot;Data from the Shakun et al. (2012) reference used by Randall&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Interestingly, while Shakun et al. (2012) does show a global temperature decrease close to $0.6^{\circ}$C 12,000 years ago, the change doesn't appear to happen abruptly (at least not on the scale of decades). In the text of the paper the authors state that they built their temperature data set from 80 different proxy measurements taken over a wide range of locations. It turns out that these proxy measurements have a relatively long time resolution (a median value of about 200 years). That means that while the changes may have occurred very quickly this temperature curve is going to fail to capture that variability and appear &quot;smoothed out&quot;. This does make the xkcd graphic a little misleading since the large temperature increase at the end is produced from data using a much finer time resolution, but this is a flaw common to all &quot;hockey stick&quot; temperature plots. &lt;/p&gt;&#xA;" OwnerUserId="908" LastActivityDate="2016-11-17T20:03:24.813" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9129" PostTypeId="2" ParentId="9103" CreationDate="2016-11-17T20:08:11.727" Score="2" Body="&lt;p&gt;The best graphic I can find is a chart from &lt;a href=&quot;https://www.ncdc.noaa.gov/paleo/abrupt/data4.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA&lt;/a&gt; covering various changes across the Younger Dryas:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BQv9P.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BQv9P.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;GISP2 data is inferred from ice cores in Greenland, Cariaco is shallow sea temperature inferred from sea-shell deposits in Venezuela. The indication is an abrupt 10 C drop in temperatures in Greenland, and about 3 C in Venezuala. Note that these are two different sources (accumulation rates and Mg/Ca ratio in shells) of information, in two different places. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Corroborating evidence can be found with a 4 C drop in the British Isles from beetle species data in &lt;a href=&quot;https://www.researchgate.net/profile/Sjoerd_Bohncke/publication/222506874_Mean_July_Temperatures_during_the_Younger_Dryas_in_Northwestern_and_Central_Europe_as_Inferred_from_Climate_Indicator_Plant_Species/links/559bbe7408aee2c16df01b1a.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Isarin and Bohnecke, 1998&lt;/a&gt; (Fig. 1); a 6.5-7.5 C drop in Switzerland from pollen analysis in &lt;a href=&quot;http://dspace.library.uu.nl/bitstream/handle/1874/19717/lotter_00_youngerdryas.pdf?sequence=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lotter, et al., 2000&lt;/a&gt;; a 3-4 C drop is sea surface temperature in the Shetlands-Faroe passage from marine sediment cores in &lt;a href=&quot;http://s3.amazonaws.com/academia.edu.documents/38630757/09ngeo439.pdf?AWSAccessKeyId=AKIAJ56TQJRTWSMTNPEA&amp;amp;Expires=1479415671&amp;amp;Signature=pPeank5jwpKjfiD%2BHssdtgC7nVo%3D&amp;amp;response-content-disposition=inline%3B%20filename%3DRapid_oceanic_and_atmospheric_changes_du.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bakke, et al., 2009&lt;/a&gt; (Fig 1, also not the big temp oscillations); again all different analysis methods and locations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All in all, there is ample evidence that there were significant temperature drops in the Younger Dryas, and spiky ones at that, given the above graph. The xkcd graph, on the other hand, shows a slow drop in temperature of about a half a degree Celcius between ~11500 and ~10500 BC. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where did xkcd get this data? I can't read the source for the references, &lt;a href=&quot;http://www.nature.com/nature/journal/v484/n7392/full/nature10915.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Shakun&lt;/a&gt;, &lt;a href=&quot;http://science.sciencemag.org/content/339/6124/1198&quot; rel=&quot;nofollow noreferrer&quot;&gt;Marcott&lt;/a&gt;, or &lt;a href=&quot;http://www.clim-past.net/9/367/2013/cp-9-367-2013.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Annan&lt;/a&gt;, so I can't really say what the author was looking at (the HadCRUT4 data from IPCC, the last source, only goes back to 1850).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a final commentary, I find this to be particularly frustrating. Normally xkcd should be considered a paragon of advancing science first thinking. Did xkcd cherry-pick the smoothest graph around to minimize the impact of 'natural' climate change and emphasize the anthropogenic? I don't know. But anthropogenic climate change is real and demonstrable, and doesn't need cartoonists to make pretty graphics that get shared &lt;a href=&quot;http://reason.com/blog/2016/09/14/send-around-this-xkcd-climate-change-web&quot; rel=&quot;nofollow noreferrer&quot;&gt;all over&lt;/a&gt; the &lt;a href=&quot;http://www.vox.com/2016/9/12/12891814/climate-change-xkcd-graphic&quot; rel=&quot;nofollow noreferrer&quot;&gt;internet&lt;/a&gt; to encourage belief in it. Infact, a wise man once said that the universe doesn't care what you believe; &lt;a href=&quot;https://xkcd.com/154/&quot; rel=&quot;nofollow noreferrer&quot;&gt;science doesn't ask for your faith, it just asks for your eyes&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="6703" LastEditDate="2017-04-24T19:47:13.987" LastActivityDate="2017-04-24T19:47:13.987" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9131" PostTypeId="2" ParentId="7537" CreationDate="2016-11-18T05:18:48.613" Score="2" Body="&lt;p&gt;Let me try to add some more information for Mr Mani.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meteosats  are satellites dedicated for meterological purposes alone operated by EUMETSAT.  INSAT satellites by India are multipurpose satellites which serve other purposes also in addition to meteorology. &lt;/p&gt;&#xA;" OwnerUserId="7002" LastActivityDate="2016-11-18T05:18:48.613" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9132" PostTypeId="2" ParentId="9067" CreationDate="2016-11-18T14:07:47.340" Score="1" Body="&lt;p&gt;After looking at the OP's definition of the biomes that are semi-arid and temperate, I decided to compare them to the biomes in WWF's &lt;a href=&quot;https://www.worldwildlife.org/science/wildfinder/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wildfinder&lt;/a&gt; and sum the area total. The WWF biomes don't really match up with the biomes defined by the OP (and originally by LC King, apparently, though I haven't read anything of his), but they at least give an alternative estimate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the Semi-Arid Biomes, I have:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;'Tropical grasslands' = '&lt;a href=&quot;http://www.worldwildlife.org/biomes/tropical-and-subtropical-grasslands-savannas-and-shrublands&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tropical and subtropical grasslands,&#xA;savannas, and shrublands&lt;/a&gt;' with 18.3 million km$^2$.&lt;/li&gt;&#xA;&lt;li&gt;'Warm Temperate Western Margin' = '&lt;a href=&quot;http://www.worldwildlife.org/biomes/mediterranean-forests-woodlands-and-scrubs&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mediterranean Forest, woodlands&#xA;and scrubs&lt;/a&gt;' with 2.9 million km$^2$.&lt;/li&gt;&#xA;&lt;li&gt;'Warm Temperate Continental' = '&lt;a href=&quot;http://www.worldwildlife.org/biomes/temperate-grasslands-savannas-and-shrublands&quot; rel=&quot;nofollow noreferrer&quot;&gt;Temperate grasslands, savannas, and&#xA;shrublands&lt;/a&gt;' at 9.9 million km$^2$.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;For a total of 31.1 million km$^2$ or 6.1% of the earth's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For Temperate, there are two listed above plus:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;'Warm Temperate Eastern Margin' + 'Cool Temperate Eastern Margin' +&#xA;'Cool Temperate Western Margin' = '&lt;a href=&quot;http://www.worldwildlife.org/biomes/temperate-broadleaf-and-mixed-forests&quot; rel=&quot;nofollow noreferrer&quot;&gt;Temperate broadleaf and mixed&#xA;forests&lt;/a&gt;' + '&lt;a href=&quot;http://www.worldwildlife.org/biomes/temperate-coniferous-forest&quot; rel=&quot;nofollow noreferrer&quot;&gt;Temperate coniferous forests&lt;/a&gt;' at 12.2 million&#xA;for broadleaf and 3.9 million km$^2$ for conifer.&lt;/li&gt;&#xA;&lt;li&gt;'Cool Temperate Continental' = '&lt;a href=&quot;http://www.worldwildlife.org/biomes/boreal-forests-taiga&quot; rel=&quot;nofollow noreferrer&quot;&gt;Boreal Forest / Taiga&lt;/a&gt;' at 14.9 million km$^2$&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;For a grand total of 43.8 million km$^2$ or 8.6% of the Earth's surface.&lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-11-18T14:07:47.340" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9133" PostTypeId="2" ParentId="9086" CreationDate="2016-11-18T16:30:17.040" Score="1" Body="&lt;p&gt;I use the &lt;a href=&quot;http://www.wrcc.dri.edu/rcc.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Regional Climate Center&lt;/a&gt; network for data. There are 6 different climate centers hosted by various research institutes, they each have their own database system for sharing data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know how it compares to the other linked sources, but what I value about the climate centers is the presence of lots of incomplete records from smaller stations. I'm not sure if those records are available through NOAA, but I do a lot of computer aggregation where more data points is more better. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-11-18T16:30:17.040" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9134" PostTypeId="2" ParentId="9083" CreationDate="2016-11-18T16:32:53.387" Score="2" Body="&lt;p&gt;This &lt;a href=&quot;http://astro.unl.edu/classaction/animations/coordsmotion/daylighthoursexplorer.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;tool&lt;/a&gt; lets you determine daylight hours from latitude for any day of the year. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I feel like this answer should be longer, but there is not much more to say.&lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-11-18T16:32:53.387" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9135" PostTypeId="2" ParentId="9112" CreationDate="2016-11-18T22:25:48.040" Score="2" Body="&lt;p&gt;Slash and burn has been used in North America and still is at times.  I see regular field burning near me where fields are particularly rocky and tilling if impractical for the crops grown.  It also occurs when there is intrusions of some noxious weeds that are controllable through fire as effectively and much cheaper than chemical controls.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, I would consider slash and burn in disfavor because of it consumptive nature.  The practice does provide some otherwise missing nutrients, but it consumes large quantities of biomass while doing so.  More favored in many regions it to use that biomass to supplement the soil by tilling it in and allowing it to aerate the soil while slowly breaking down and augmenting the soil.  Between being fortunate enough to have good soil to begin with, or the ability to augment with either natural or chemical supplements, many North American farms do not need the quick fix burning can supply so opt for the slower, longer term solution of turning in the organic materials.&lt;/p&gt;&#xA;" OwnerUserId="6178" LastActivityDate="2016-11-18T22:25:48.040" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9136" PostTypeId="2" ParentId="9112" CreationDate="2016-11-19T02:37:16.437" Score="1" Body="&lt;p&gt;The term &quot;slash and burn&quot; is generally not used to describe the field burning that is currently done in North America.  Burning fields is illegal in some states.  It is allowed in other states, but is usually regulated under a &lt;a href=&quot;http://www.ksfire.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Smoke Management Plan&lt;/a&gt;.  Smoke exposure is a serious health concern and particulate matter pollution is regulated under the &lt;a href=&quot;https://www.epa.gov/laws-regulations/summary-clean-air-act&quot; rel=&quot;nofollow noreferrer&quot;&gt;Clean Air Act&lt;/a&gt; in the USA.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many states only allow field burning at certaim times, based on &lt;a href=&quot;http://www.bcairquality.ca/readings/ventilation-index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;atmospheric ventilation&lt;/a&gt; and current &lt;a href=&quot;http://firedanger.cr.usgs.gov/firepotential.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;fire potential&lt;/a&gt; on the natural landscape.  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;If there is an atmospheric temperature inversion near the surface, or stagnant air characterized by no winds, then burning is not permitted.  &lt;/li&gt;&#xA;&lt;li&gt;If the natural landscape is covered with dry fuels, burning will not be permitted so as to reduce the risk of wildfire. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Another common practice is for government owned lands to have &lt;a href=&quot;https://www.blm.gov/mt/st/en/info/newsroom/2015/october/prescribed_fire_aims.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;prescribed fire&lt;/a&gt; put to the ground, which simulates natural conditions and removes invasive species (e.g. on rangelands). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When field burning or broadcast prescribed burns are not possible, pile burns are conducted (e.g. piles from timber slash, orchard tear-outs, mixed brush, etc.).  Pile burns ensure that the fire does not go wild and that there is enough heat flux to allow the smoke plume to break through a temperature inversion. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, while North America does not typically employ &quot;slash and burn&quot; nomenclature, there is certainly a lot of slash being burned.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2016-11-27T15:39:53.640" LastActivityDate="2016-11-27T15:39:53.640" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9137" PostTypeId="2" ParentId="8578" CreationDate="2016-11-19T04:09:11.300" Score="1" Body="&lt;p&gt;You may also want to consider alternative viewpoints, from less politically engaged scientists. These might not be &quot;reviews&quot;, but a lot of to think about.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1) Testimony of MIT &lt;a href=&quot;https://en.wikipedia.org/wiki/Richard_Lindzen&quot; rel=&quot;nofollow noreferrer&quot;&gt;Professor Richard S. Lindzen&lt;/a&gt;, the testimony &lt;a href=&quot;http://eaps.mit.edu/faculty/lindzen/Testimony/Senate2001.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;before Senate, 2001&lt;/a&gt;,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) &lt;a href=&quot;https://en.wikipedia.org/wiki/John_Christy&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dr. John R. Christy&lt;/a&gt;, Distinguished Professor of Atmospheric Science at the University of Alabama in Huntsville, Satellite measurements, &lt;a href=&quot;https://www.commerce.senate.gov/public/_cache/files/fcbf4cb6-3128-4fdc-b524-7f2ad4944c1d/80931BD995AF75BA7B819A51ADA9CE99.dr.-john-christy-testimony.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;his Testimony before US Senate in 2015&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6584" LastEditorUserId="6584" LastEditDate="2016-11-23T07:30:03.327" LastActivityDate="2016-11-23T07:30:03.327" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9138" PostTypeId="1" AcceptedAnswerId="9172" CreationDate="2016-11-19T05:17:54.643" Score="7" ViewCount="197" Body="&lt;p&gt;The BBC news article &lt;a href=&quot;http://www.bbc.com/news/world-asia-37996276&quot; rel=&quot;noreferrer&quot;&gt;New Zealand quake: The geological impact of a 'complex' tremor&lt;/a&gt; says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The powerful earthquakes which hit New Zealand were some of the most complex ever recorded, say scientists.&lt;/p&gt;&#xA;&lt;p&gt;Most earthquakes are the result of rupture on a single fault plane. But the twin quakes led to the rupture of at least six faults, including a newly identified one at Waipapa Bay.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The article describes several resulting changes after the 7.8 magnitude &lt;a href=&quot;https://en.wikipedia.org/wiki/2016_Kaikoura_earthquake&quot; rel=&quot;noreferrer&quot;&gt;2016 Kaikoura earthquake&lt;/a&gt;, including seabeds raised above the surface, a dangerous 150m-high landslide dam has formed on the Hapuku River, and a town completely cut-off by landslides:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Kaikoura itself was completely cut off by landslides. About 1,000 tourists and locals have been evacuated by sea from the small town...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The image below is one of several from the article.&lt;/p&gt;&#xA;&lt;p&gt;It's hard for me to understand what happened. It seems there were actually two distinct major earthquakes in rapid succession, and a lot of other motion and changes in nearby related faults. Was seismic data alone used to reach this conclusion, or is it a complex analysis of seismic, satellite, and ground-truth data used to &amp;quot;reconstruct&amp;quot; what actually happened? Is there some more technical description of the analysis available?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/a0TBj.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/a0TBj.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2016-12-30T20:24:45.240" Title="How do they know the 2016 Kaikoura (NZ) Earthquake was 'complex', involved six different faults?" Tags="|seismology|earthquakes|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9139" PostTypeId="2" ParentId="9078" CreationDate="2016-11-19T08:04:24.183" Score="1" Body="&lt;p&gt;The 2016 paper &quot;&lt;a href=&quot;http://advances.sciencemag.org/content/2/3/e1500621.full&quot; rel=&quot;nofollow noreferrer&quot;&gt;A case for historic joint rupture of the San Andreas and San Jacinto faults&lt;/a&gt;&quot; reports of research suggesting that simultaneous large earthquakes occurred in 1812 in California, the researchers used&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;dynamic rupture modeling to show that paleoseismic and historic observations associated with the earthquake of 8 December 1812 can be explained by joint rupture of the SAF and SJF.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(SAF = San Andreas Fault and SJF = San Jacinto Fault)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the author stresses that what they have is a model, rather than a certainty.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alot of research centres around the notion of 'near-simultaneous earthquakes', such as the 2009 South Pacific earthquake, as described in the article &quot;&lt;a href=&quot;https://www.scientificamerican.com/article/tonga-samoa-earthquakes/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Double Shake: Multiple, Nearly Simultaneous Earthquakes Triggered Deadly 2009 Tsunami&lt;/a&gt;&quot; where studies suggest that at least 2 quakes of similar magnitude occurred within 50km of eachother, separated by minutes - another similar study suggests that one of the quakes 'obscured' another nearby rupture of equal or higher magnitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Italy is another place where simultaneous or near-simultaneous earthquakes seem to occur and resulted in several studies, one of which being reported in the article &quot;&lt;a href=&quot;http://phys.org/news/2014-09-near-simultaneous-earthquakes-complicate-seismic-hazard.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Likely near-simultaneous earthquakes complicate seismic hazard planning for Italy&lt;/a&gt;&quot;, stating that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It's very important to consider this scenario of earthquakes, occurring possibly seconds apart, one immediately after another&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Stating that this scenario would have an 'amplification' effect of the the effects of the shhaking (hence, the researchers' concern).  A particular example they cite is&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The 1980 Irpinia earthquakes included a sequence of three events, occurring at intervals within 20 seconds of each other.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Another compelling example, reported in the article &quot;&lt;a href=&quot;http://www.earthmagazine.org/article/sumatran-strike-slip-earthquakes-challenge-seismologists&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sumatran strike-slip earthquakes challenge seismologists&lt;/a&gt;&quot; that occurred in April, 2012 - a strike-slip fault induced quake of a magnitude of 8.6 on the richter Scale, one of the theories for the great magnitude is explained as&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Another apparent reason for the large magnitude, says Miaki Ishii, a sesimologist at Harvard University, is that &lt;strong&gt;multiple faults appear to have slipped almost simultaneously&lt;/strong&gt;, creating a &lt;strong&gt;composite earthquake&lt;/strong&gt;. “If it was just a single fault activation, it wouldn’t have been large as 8.6. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;An important note the Harvard seismologist makes, that essentially answers your question regarding simultaneous (and near-simulatneous earthquakes), is that observations of this kind of fault activation, which is described as &quot;a cascading failure of faults&quot; are seen in a lot of large earthquakes.&lt;/p&gt;&#xA;" OwnerDisplayName="user7009" LastEditorDisplayName="user7009" LastEditDate="2016-11-19T08:14:03.630" LastActivityDate="2016-11-19T08:14:03.630" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9140" PostTypeId="1" AcceptedAnswerId="9168" CreationDate="2016-11-19T11:35:25.810" Score="1" ViewCount="77" Body="&lt;p&gt;Is it legal to mine/collect and keep minerals in the UK for educational purposes? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would also like to know if there are any notable mineral deposits located in the UK midlands.&lt;/p&gt;&#xA;" OwnerUserId="7010" LastEditorUserId="5536" LastEditDate="2016-11-19T15:31:21.657" LastActivityDate="2016-11-21T20:21:08.883" Title="Mining and keeping UK minerals?" Tags="|geology|minerals|mining|" AnswerCount="1" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9143" PostTypeId="5" CreationDate="2016-11-19T19:38:59.107" Score="0" Body="&lt;p&gt;It extends from ground to about 8 km (poles) - 20 km (tropics) and contains about 75% of the atmosphere' s total mass. Temperature decreases with approximately 1K/100m in absence of clouds.&lt;/p&gt;&#xA;" OwnerUserId="6441" LastEditorUserId="6441" LastEditDate="2016-11-20T08:07:34.480" LastActivityDate="2016-11-20T08:07:34.480" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9144" PostTypeId="4" CreationDate="2016-11-19T19:38:59.107" Score="0" Body="The troposphere is the lowest part of Earth's atmosphere and place of our daily weather phenomenons. When asking questions specifically about the troposphere, use this tag and also include the  [atmosphere] tag and [meteorology] tag." OwnerUserId="6441" LastEditorUserId="6441" LastEditDate="2016-11-20T08:07:38.840" LastActivityDate="2016-11-20T08:07:38.840" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9145" PostTypeId="5" CreationDate="2016-11-19T19:58:25.560" Score="0" Body="&lt;p&gt;The upper atmosphere contains the thermosphere and exosphere. The Kármán line, or Karman line (100km) is commonly used to define the boundary between aviation and aerospace. &lt;/p&gt;&#xA;" OwnerUserId="6441" LastEditorUserId="6441" LastEditDate="2016-11-20T08:06:49.383" LastActivityDate="2016-11-20T08:06:49.383" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9146" PostTypeId="4" CreationDate="2016-11-19T19:58:25.560" Score="0" Body="The upper-atmosphere is the part of earth's atmosphere that is above the homosphere (where all gases are well mixed) and starts at approximatly 100km. When asking questions specifically about the upper-atmosphere, use this tag and also include the [atmosphere] tag and [meteorology] tag if appropriate." OwnerUserId="6441" LastEditorUserId="6441" LastEditDate="2016-11-20T08:07:12.590" LastActivityDate="2016-11-20T08:07:12.590" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9147" PostTypeId="1" AcceptedAnswerId="9151" CreationDate="2016-11-19T20:12:13.377" Score="6" ViewCount="2381" Body="&lt;p&gt;Looking at a globe, Antarctica looks remarkably centered on the south pole. Has the rotation of the earth had any effect on the position of the landmass?&#xA;&lt;img src=&quot;https://i.stack.imgur.com/flXe7.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="7013" LastEditorUserId="2470" LastEditDate="2021-07-06T07:07:36.417" LastActivityDate="2021-07-06T07:07:36.417" Title="Is it coincidence that Antarctica is centered on the south pole?" Tags="|earth-rotation|tectonics|antarctica|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9149" PostTypeId="1" AcceptedAnswerId="9235" CreationDate="2016-11-20T01:37:53.463" Score="3" ViewCount="180" Body="&lt;p&gt;Does the atmosphere depth (or how high the air molecules from the ground) of Earth or Mars differ gradually or can there be plumes of atmosphere that reaches into space? If I were able to travel a perfect circle around the equator would the atmosphere differ in elevation?&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2016-11-24T05:51:50.580" LastActivityDate="2016-12-01T23:46:10.550" Title="Elevation of Atmosphere differ?" Tags="|atmosphere|clouds|thermodynamics|air-currents|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9150" PostTypeId="1" CreationDate="2016-11-20T06:28:16.363" Score="3" ViewCount="197" Body="&lt;p&gt;This extreme difference from normal -- could it occur in climates that are warmer, making some places unlivable? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, is there a reason why extremely cold places should expect to have relatively warmer anomalies than climates that are warmer on average?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://www.sciencealert.com/the-north-pole-is-36-degrees-hotter-than-it-should-be-right-now&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.sciencealert.com/the-north-pole-is-36-degrees-hotter-than-it-should-be-right-now&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7016" LastEditorUserId="39" LastEditDate="2016-11-22T10:02:48.817" LastActivityDate="2016-11-22T10:02:48.817" Title="Implications of recent 36 degrees Fahrenheit (20C) anomaly at North Pole?" Tags="|climate|climate-change|arctic|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9151" PostTypeId="2" ParentId="9147" CreationDate="2016-11-20T07:07:38.907" Score="4" Body="&lt;p&gt;It's an interesting thought.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Antarctica is not so balanced as it might appear on the maps. East Antarctica is old, consisting probably of cratons and Proterozoic orogenic domains whiles West Antarctica is much younger, thinner and have mostly been accreted during the formation of Gondwana (See e.g &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S1342937X10001759&quot; rel=&quot;nofollow noreferrer&quot;&gt;Boger 2011&lt;/a&gt;). If there was a direct control of the location of the continents from the rotation, one would expect East Antarctica to be centered rather than the whole landmass as it appears today, moreover one would expect a similar continent, resting at the North Pole. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, Antarctica have been relatively stable, at least for the last 200My. The breakup of Gondwana could partly be simplified as one continent after the other radiating away from Antarctica, that mostly stayed in the same latitudes (See e.g &lt;a href=&quot;https://www.researchgate.net/publication/222827048_Plate_tectonics_and_net_lithosphere_rotation_over_the_past_150_My&quot; rel=&quot;nofollow noreferrer&quot;&gt;Torsvik et al. 2010&lt;/a&gt;). Today Antarctica has relatively low tectonic activity and little continental drift, mostly a rotational component. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My personal believe is that astronomic potential fields, as gravitational tidal forces, might become a more important parameter in future for mantle dynamic models and maybe even some tectonic mechanisms, but I might be wrong and studies so far (e.g. &lt;a href=&quot;http://151.100.51.154/dst1/sciterra/sezioni/doglioni/Publ_download/2009RiguzzietalTectonophysics.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;) have not shown good evidences and didn't attract much attention. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2016-11-20T07:17:19.547" LastActivityDate="2016-11-20T07:17:19.547" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9152" PostTypeId="2" ParentId="9150" CreationDate="2016-11-20T09:16:11.960" Score="3" Body="&lt;p&gt;I don't know where you get the 36 degrees from - it seems rather extreme. Do you mean 36 deg F = 20 deg C? Even 20 is not realistic, except perhaps for a very short period anomaly. In fact, the average temperature increase in the north pole area is little more than 4 degrees C. see &#xA;&lt;a href=&quot;https://nsidc.org/cryosphere/arctic-meteorology/climate_change.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://nsidc.org/cryosphere/arctic-meteorology/climate_change.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PDT1q.gif&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;from NASA-GIFF&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PDT1q.gif&quot; alt=&quot;https://nsidc.org/sites/nsidc.org/files/images//arctic-amplification-1960-2011-hires.gif&quot; title=&quot;from NASA-GIFF&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, the Earth's atmospheric heat distribution is to shunt heat polewards, and it is universally recognized that the lion's share of the temperature rise from climate change will occur in polar areas (for several reasons). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to some places becoming unlivable, yes indeed, parts of the tropics and some places further north, are already heading towards that state. One thinks of North India where heat waves are now reaching the mid to high 40s (centigrade), which is the sort of temperature where people who can't afford air conditioning drop dead from heat exhaustion. This is likely to get worse. &#xA;Also, be aware that there are many +/- anomalies, including oceanic islands (high humidity) and coastal sub-Saharan Africa, where an increase of about 1.5 deg C above historic means are already making life difficult for some. &#xA;In the Arctic dramatic changes in lifestyle are also occurring, and will continue to do so at an accelerating rate. The 2 deg C limiting temperature rise, beloved of politicians (and which is already looking unattainable), is just a &lt;em&gt;global&lt;/em&gt; average, within which the Arctic temperature rise could easily exceed 10 deg C. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-11-20T09:16:11.960" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9153" PostTypeId="2" ParentId="8378" CreationDate="2016-11-20T10:09:48.287" Score="2" Body="&lt;p&gt;A recent 2016 Stanford University study reported in the article &quot;&lt;a href=&quot;https://earth.stanford.edu/news/oxygen-starved-oceans-held-back-lifes-recovery-after-great-dying&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oxygen-starved oceans held back life's recovery after the 'Great Dying'&lt;/a&gt;&quot;, suggests that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Analysis of ancient seabed rocks from disparate locations reveal that life did not rebound until anoxia had fully ebbed.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Specifically, the researchers found evidence from a lot of places around the world that, according to the researchers, point to a possible conclusion that &lt;em&gt;globally&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;anoxic conditions reduced seawater oxygen levels by 100-fold at the onset of the mass extinction. Oxygen levels then slowly rose, only returning to pre-extinction levels after 5 million years, corresponding to when the climate became more stable and life regained its former diversity.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This research paints a picture that the mass extinction event resulted in a global anoxic event, that took the Earth a considerable amount of time to recover from.&lt;/p&gt;&#xA;" OwnerDisplayName="user7009" LastActivityDate="2016-11-20T10:09:48.287" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9154" PostTypeId="2" ParentId="8378" CreationDate="2016-11-20T14:01:46.267" Score="1" Body="&lt;p&gt;Let me propose that if an anoxia event were a cause of the P-T marine extinction; then it wouldn't be Pangaea that would slow recovery, but Panthalassa; the global ocean counterpart to Pangaea. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a map of the oceanic conveyor:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XQJkU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XQJkU.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Its complex structure is driven by the location of the continents. Without continents spread around the world, the ocean circulation would look more like the Pacific ocean, with three separate gyres (probably four if Antarctica was not there, as in the Permian) and much smaller areas of upwelling water:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/M5t0W.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/M5t0W.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reduced complexity of ocean circulation could reduce the ability of the ocean recover oxygen levels. Deep water anoxia especially would take far longer to correct with reduced upwelling currents.&lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-11-20T14:01:46.267" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9155" PostTypeId="2" ParentId="9150" CreationDate="2016-11-20T14:13:06.413" Score="4" Body="&lt;p&gt;The specific 36 F temperature anomaly in the linked article points to a single day event. I am aware that it is associated with unusually high temperatures in general this fall/winter, but a single day event is not that unusual. For example, the average January temperature in Dallas is 46 F, and the average monthly high is 76 F. That means every year (on average) sees a temperature that is 30 F above normal. The record high in January is 88 F, meaning that at least once, the temperatures in Dallas were 42 F above normal. That was all the way back in 1969. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;While this doesn't look great for the polar bears, and is further confirmation that AGW is coming along nicely, I would caution against getting too upset about it in the short term. We aren't out of time yet. After all, the world didn't end after that record January heat in 1969. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-11-20T14:13:06.413" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="9156" PostTypeId="1" AcceptedAnswerId="9162" CreationDate="2016-11-20T16:11:34.690" Score="3" ViewCount="106" Body="&lt;p&gt;So I live in Texas, and it get awfully hot in the summer- like 37°C hot- and yet, when winter rolls around, it can get down to 4° or 5° pretty easily. So, my limited understanding or weather and stuff doesn't understand one thing. Where'd all that heat go? It was so hot in summer but it'll disappear in a week. I know cold is just the absence of heat, so the heat must've gone somewhere, right?&lt;/p&gt;&#xA;" OwnerUserId="7017" LastActivityDate="2016-11-21T03:30:21.907" Title="Where'd Summer go?" Tags="|meteorology|temperature|seasons|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9157" PostTypeId="1" CreationDate="2016-11-20T18:52:26.217" Score="7" ViewCount="136" Body="&lt;p&gt;You can see planetary/rossby waves in the meanders of the jet stream. In short: If an air parcel moves from warm subtropics towards the pole, it will deviate toward the east due to conservation of angular momentum (movement towards the equator will lead to deviation toward the west). That results in a meandering motion. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How will climate change affect planetary wave activity and zonal wavenumber?&#xA;Does polar amplification reduce planetary activity because of a smaller temperature gradient between subtropics and polar region? Will cooling of the stratosphere influence planetary waves as well?&lt;/p&gt;&#xA;" OwnerUserId="6441" LastActivityDate="2016-11-22T13:21:34.143" Title="How will climate change affect planetary waves?" Tags="|meteorology|atmosphere|climate-change|waves|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9158" PostTypeId="5" CreationDate="2016-11-20T19:07:17.190" Score="0" Body="&lt;p&gt;Mesoscale meteorology is divided into three subclasses:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Meso-alpha: 200–2000 km, e.g. fronts, tropical cyclones &lt;/li&gt;&#xA;&lt;li&gt;Meso-beta:  20–200 km, e.g. orographic cyclones, squall lines&lt;/li&gt;&#xA;&lt;li&gt;Meso-gamma: 2–20 km, e.g. high convection, thunderstorms&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6441" LastEditorUserId="6441" LastEditDate="2016-11-21T12:38:25.643" LastActivityDate="2016-11-21T12:38:25.643" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9159" PostTypeId="4" CreationDate="2016-11-20T19:07:17.190" Score="0" Body="Use mesoscale tag for atmospheric processes with a horizontal extension from 2 km up to 2000 km. Examples are: thunderstorms, sea breezes, squall lines, fronts, tropical cyclones" OwnerUserId="6441" LastEditorUserId="6441" LastEditDate="2016-11-21T00:07:05.743" LastActivityDate="2016-11-21T00:07:05.743" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9160" PostTypeId="2" ParentId="9156" CreationDate="2016-11-21T00:57:26.657" Score="1" Body="&lt;p&gt;User 32214, I suggest you draw back from Texas, disregard local weather anomalies (which don't count for much), and look at the bigger picture. Major seasonal changes in the heat distribution occur by three main processes. By far the most important is day length / relative accumulation of solar energy caused by the way the Earth's spin is inclined to the plane of orbit of the planet. This yields the normal seasonal variation. In addition, Hadley cells redistribute tropical heat polewards, whilst continental-scale (and larger) loops in the various jet streams bring thermal anomalies on a scale of weeks or even months. These processes bring inter-annual variations in the climate at any given location. Jet stream meteorology is rather complex, but a good summary is found in the clip:&#xA;&lt;a href=&quot;https://www.youtube.com/watch?v=6aLk6b0vNUc&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=6aLk6b0vNUc&lt;/a&gt;&#xA;The effect of climate change is to push extra heat polewards. This reduces the thermal gradient between either side of the polar jet stream, thus making the jet more sluggish in its migration around the world. This sluggishness causes the jet to slow, and create north-south loops, yielding extra cold anomalies on the cold side, and extra hot anomalies on the equatorial side. These account for record breaking hot and cold anomalies in North India, Moscow, Western Europe, and maybe Texas (though I am not familiar with Texan weather systems). So the short answer to your question is in two parts. Firstly, there is the major annual shift in climate due to the Earth's spin angle relative to the sun. Second, less important, but more interesting is the that climate change is very slightly beginning to alter the heat distribution of the planet. &lt;em&gt;Or&lt;/em&gt;, you can adopt Donald Trump's 'science-free' head in the sand policy, in which case any climatic trend is a total mystery!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recently we have seen a rather odd scenario developing, in which the polar and subtropical jet streams have been merging. These are normally very different and distinct. Maybe this is a one-off anomaly, or maybe we are entering uncharted territory, where it will be harder to predict hot and cold spells - at least until we get a better handle upon how climate change will influence future jet streams.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS another factor is the annual oscillation of the inter-tropical convergence zone, but I suspect Texas is too far north to be involved in that process.  &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2016-11-21T01:14:51.207" LastActivityDate="2016-11-21T01:14:51.207" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9161" PostTypeId="1" CreationDate="2016-11-21T03:12:15.303" Score="5" ViewCount="1199" Body="&lt;p&gt;The capillary fringe is the area above the water table where the water is held in tension so that the connected pore space is completely saturated, although variation in pore size means that there is variability in the height of capillary rise, and thus, the thickness of the capillary fringe can include a zone where the largest pores are not saturated (a number of workers only consider the zone where all pores are saturated as the capillary fringe). The capillary fringe can be several meters thick in clays. Above the capillary fringe, there is a zone of variable water saturation called the vadose zone where water is held in tension but the pores are not fully saturated. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can water wick up into the vadose zone from the capillary fringe to any significant distance (say more than a cm or so) and to any significant amount? If a plant has roots in the vadose zone, that do not reach the saturated capillary fringe, perhaps 30 cm to a meter or more above the fringe, could they obtain a significant amount of water from the saturated groundwater?&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2022-05-19T16:21:12.473" Title="How far can water wick up above the capillary fringe in sediment or soil?" Tags="|hydrology|hydrogeology|water-table|unsaturated-zone|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9162" PostTypeId="2" ParentId="9156" CreationDate="2016-11-21T03:30:21.907" Score="1" Body="&lt;p&gt;The heat goes away in two main ways. The first is radiation as mentioned in a comment. Heat radiates away into space or it may warm the air before it gets to space. That leads to the second reason heat goes away - convection. Weather systems move air from one place to another. The hot air literally blows away or rises and is replaced by cooler air that blows in. Where there is mixing, the warm air warms up the cooler air so the mixed air approaches the same temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are a couple of other ways that heat is lost. First, water in lakes and rivers evaporates so you get evaporative cooling like a swamp cooler. That is most noticeable in summer but happens at a slower rate as air temperature decreases and as the sun stays up for fewer hours in the autumn and stays lower in the sky. Plants transpire water vapor from their leaves and that has the same effect as evaporation. The other way is by melting snow or ice. When snow falls on warm ground early in the winter, the ground has retained enough heat to melt the snow. This cools the ground to the point where the snow will stick.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2016-11-21T03:30:21.907" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9163" PostTypeId="1" CreationDate="2016-11-21T04:02:21.707" Score="9" ViewCount="1196" Body="&lt;p&gt;I've been trying to make sense of the argument surrounding sea level rise and not getting very far.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Those who claim that Sea Level Rise is insignificant generally assert that we have been unable to statistically link rising Greenhouse Gas levels to rising sea levels. I assume that this is incorrect, but I do not have the knowledge to analyze this and have not heard the claim refuted before.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to know whether Sea Level Rise is linked to Greenhouse Gas emissions and what the mechanisms are behind it.&lt;/p&gt;&#xA;" OwnerUserId="7018" LastEditorUserId="5536" LastEditDate="2016-11-21T07:25:40.063" LastActivityDate="2017-01-12T01:52:07.153" Title="Sea Level Rise due to Climate Change" Tags="|climate-change|sea-level|statistics|thermodynamics|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9165" PostTypeId="2" ParentId="9163" CreationDate="2016-11-21T13:07:53.053" Score="6" Body="&lt;p&gt;It's a harder direct relation to show that it appears.   On the surface, warmer = less ice, file under &quot;duh&quot;, but while it probably is that simple, showing a causal relation is a more difficult.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The thermal expansion aspect of the question is easy enough.   Warmer air warms the ocean surface which slowly warms the ocean.  About 90% of the heat trapped by man made climate change currently goes into the oceans.   See &lt;a href=&quot;http://www.skepticalscience.com/graphics.php?g=12&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;, or &lt;a href=&quot;https://www.washingtonpost.com/news/energy-environment/wp/2016/01/18/this-is-where-90-percent-of-global-warming-is-going/?utm_term=.92efbff1e8fb&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.  That's an enormous amount of heat, but the Oceans are large enough that the expansion and increase in temperature moves pretty slowly.   About 1/3rd of the current sea level increase is attributed to thermal expansion, which works out to about 1/3rd of 1 inch every 10 years, or, roughly 1 mm per year.  (Thermal expansion only).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Sea_level_rise#21st_century&quot; rel=&quot;noreferrer&quot;&gt;Source.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Melting glaciers are more difficult to show a direct relation.  By this &lt;a href=&quot;https://nsidc.org/data/docs/noaa/g01130_glacier_inventory/&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt; there are over 130,000 glaciers in the world, and while there is a fair bit of overlap, to properly show a causal relation, you'd need to look at individual glaciers to determine the cause.   You wouldn't need to look at all 130,000, but you'd need a solid sampling to demonstrate a causal relation.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What's more, under the right conditions, glaciers can grow larger as the local weather grows warmer.   Warmer weather can lead to increased snowfall, which can enable glaciers to grow, even in a warmer climate.  Article on that &lt;a href=&quot;http://www.livescience.com/48256-asia-karakoram-glaciers-stability.html&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The two simplest ways to make this argument is looking at the percentage of glaciers that are melting or to look at total ice volume in those glaciers.  (For the 2nd one, I'd ignore the continental ice sheets and just look at the smaller glaciers), but it can be done either way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By this &lt;a href=&quot;https://www.skepticalscience.com/himalayan-glaciers-growing.htm&quot; rel=&quot;noreferrer&quot;&gt;article&lt;/a&gt;, about 90% of glaciers are shrinking world wide.   If climate wasn't changing, I'd expect that to be closer to 50%.   Even when climate is changing, for example, when ice ages stop are start, those are usually driven by the Northern Hemisphere having colder summers (begins the ice age) or the Northern Hemisphere having warmer summers (ends the ice age), with the Southern Hemisphere behaving in the opposite way.   That suggests to me that even during the rise or fall of ice ages, 90% of the glaciers moving in the same direction probably doesn't happen.   90% of glaciers losing ice appears to be strong evidence of being caused by climate change, but that ratio lacks statistical teeth because there's no historical data to show that 90% of the world's glaciers losing ice is unusual.   It seems unusual, but it's difficult to prove.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other avenue would be to look at the total amount of loss of ice in the world's glaciers.  See page below.  I didn't see a number listed anywhere, but a quick calculation, Earth's glaciers are losing on average about 60 cubic miles of ice in an average year.   That's pretty significant ice loss.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;cdn.antarcticglaciers.org/wp-content/uploads/2014/11/images_Assessment-Reports_AR5-WG1_Chapter-04_Fig4-25_errata.jpg&lt;/p&gt;&#xA;&#xA;&lt;p&gt;from &lt;a href=&quot;http://www.antarcticglaciers.org/glaciers-and-climate/mapping-worlds-glaciers/&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But both these arguments have the same weakness.  Both seem to be very good evidence, neither shows a causal relation.   The only way to do it scientifically would be to go through a large enough sample size of glaciers and show a pattern of causality.  At least, I don't see any other way to show a direct relation.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, saying &quot;90% of the worlds glaciers are losing ice&quot; is a pretty good argument, as is saying that Earth's glaciers lose about 60 cubic miles of ice in an average year.    &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2016-11-21T13:07:53.053" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9166" PostTypeId="2" ParentId="9163" CreationDate="2016-11-21T13:08:42.720" Score="14" Body="&lt;p&gt;The first part of the association is that increasing levels of greenhouse gases in the atmosphere will cause rising temperatures on earth. &lt;a href=&quot;https://earthscience.stackexchange.com/questions/8516/are-we-changing-earths-weather-with-global-warming/8951#8951&quot;&gt;Here&lt;/a&gt; is some information on why that is so, if you are interested. Now assuming that temperatures are currently going up (they are), there are two mechanisms that will connect this to rising sea level, melting of ice on land, and thermal expansion of water  &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Land Ice&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;As climate lawyers are quick to point out, if floating sea ice melts, it doesn't really change the level of the ocean (much) because floating ice displaces a volume equal to an equivalent mass of water. As we will see in the next part, the temperature change from ice melting and then warming will cause some changes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meanwhile, there is about 2.8 million cubic km of ice locked in Greenland's ice cap and 26 million in Antarctica. These two sheets, if fully melted would cause about 7m and 58m of sea level rise, respectively. They will not melt immediately; while the topic is under debate, Greenland will probably take a millennium to melt completely. Antarctica is larger, colder and more isolated from world temperatures fluctuations due to the circumpolar currents, and would probably take a much longer time to melt fully. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Thermal Expansion of water&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The density of seawater changes with temperature. Using data from &lt;a href=&quot;http://www.unisense.com/files/PDF/Diverse/Seawater%20&amp;amp;%20Gases%20table.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this chart&lt;/a&gt; (Data-Table 9), the density of seawater (at 35000 ppm salinity) at 10 C is $1.0270 \frac{\text{g}}{\text{cm}^3}$ and at 15 C is at $1.0260 \frac{\text{g}}{\text{cm}^3}$. Therefore, there is an estimated $\frac{1.027-1.026}{5} = .001 \frac{\text{g}}{\text{cm}^3}$ change per degree C, or a $\frac{.001}{1.027} = .097 \% $ increase in volume for a one degree C increase in temperature from 10 C to 11 C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not all the earth's ocean's are at 10 C, but using this as an estimator, the $1.35 \times10^9 \text{ km}^3$ will increase by $1.31 \times10^6 \text{ km}^3$ with a 1 C increase in temperature. If you divide that by the surface area of the ocean, 510 million $\text{ km}^2$, you get an approximately 2.5 meter increase in sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That calculation is not at all rigorous; deep ocean water is colder than 10 C and at lower temperatures thermal expansion is much less (just look at the linked chart to see), but it does demonstrate that there will be a detectable rise in sea level from thermal expansion of seawater as the planet heats up. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2017-01-12T01:52:07.153" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9167" PostTypeId="2" ParentId="9086" CreationDate="2016-11-21T20:07:00.660" Score="0" Body="&lt;p&gt;This is my favorite resource for historical climate data &lt;a href=&quot;http://cdiac.ornl.gov/epubs/ndp/ushcn/ushcn.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://cdiac.ornl.gov/epubs/ndp/ushcn/ushcn.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7023" LastActivityDate="2016-11-21T20:07:00.660" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9168" PostTypeId="2" ParentId="9140" CreationDate="2016-11-21T20:21:08.883" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Can I go to forests, national parks or mineral deposits and mine&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I think the basic answer to this question is No, or rather, not without the land owners permission.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example it is illegal to remove pebbles from a beach: &lt;a href=&quot;http://www.mirror.co.uk/news/uk-news/woman-who-stole-pebbles-beach-2330090&quot; rel=&quot;nofollow noreferrer&quot;&gt;Woman who 'stole' pebbles from a BEACH to decorate in her garden given police warning&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For more information on mineral ownership in the UK see: &lt;a href=&quot;http://www.bgs.ac.uk/mineralsuk/planning/legislation/mineralOwnership.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Legislation &amp;amp; policy: mineral ownership&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="477" LastActivityDate="2016-11-21T20:21:08.883" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9169" PostTypeId="2" ParentId="9163" CreationDate="2016-11-21T20:27:41.753" Score="3" Body="&lt;p&gt;The argument and science behind this idea is well summarized on the &lt;a href=&quot;http://www.ucsusa.org/global_warming/science_and_impacts/impacts/infographic-sea-level-rise-global-warming.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Union of Concerned Scientist web page on global warming as it causes sea levels to rise&lt;/a&gt;. There is a link to a white paper which lists various information sources and studies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically, the claim is that CO2 makes the earth warmer by insulating the earth and preventing the escape of long-wave radiation, and this higher average temperature causes glaciers to melt and the sea level to rise due to the addition of meltwater.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(The argument is not heard too often these days because of the historical problem. In Roman times (1800-2300 years ago) sea levels were substantially lower than they are today, yet the earth's climate was warmer than the modern climate. For example, in Roman times Britain grew grapes commercially and was a big wine exporter, but now that is no longer possible because the climate of Britain is too cold to grow grapes. So, as a consequence of this problem, the sea level thing is not touted as much as it used to be back in the 1980s before the contradiction was noticed.)&lt;/p&gt;&#xA;" OwnerUserId="2491" LastEditorUserId="2491" LastEditDate="2016-11-21T20:41:53.940" LastActivityDate="2016-11-21T20:41:53.940" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9170" PostTypeId="2" ParentId="9046" CreationDate="2016-11-21T21:40:45.263" Score="4" Body="&lt;p&gt;There are a lot of aspects affecting daily temperature. I want to distinguish between factors, which may change from day to day and others which are fixed and thus affect more the annual cycle of temperature (like &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9038/why-is-it-colder-in-the-mountains-than-at-sea-level&quot;&gt;altitude of place&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some factors which affect daily temperature and change daily:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;prevailing winds (temperature/moisture advection)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;cloudiness&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;day of the year: duration of day (and thus insolation) is important for daily temperature range. The longer sun shines, the more solar radiation is absorbed by surface and the higher temperatures you get. For example, during equinox (march and september) day and night have the same duration and you have the longest or shortest day during solstice (in June and December). Thus this aspect is more relevant at middle and high latitudes.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Other aspects which do not change daily:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;local relief and surface type (atmosphere is heated due to absorption of solar radiation by surface)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;distance to ocean/large lake (maritime vs. continental climate)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;latitude: the angle of incidence of solar radiation changes with latitude (and day of the year)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6441" LastEditorUserId="6441" LastEditDate="2016-11-21T21:45:45.723" LastActivityDate="2016-11-21T21:45:45.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9172" PostTypeId="2" ParentId="9138" CreationDate="2016-11-22T11:46:38.713" Score="4" Body="&lt;p&gt;You need to see the &lt;a href=&quot;https://en.wikipedia.org/wiki/Interferometric_synthetic_aperture_radar&quot; rel=&quot;nofollow noreferrer&quot;&gt;InSAR&lt;/a&gt; data. E.g., see this &lt;a href=&quot;https://pbs.twimg.com/media/Cxb7tVZUAAA6EWa.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;image&lt;/a&gt; which is based on radar data acquired by ESA's Sentinel-1A satellite. For straight faults the pattern is not this complicated. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using such observations we can estimate which parts of the fault slipped. E.g., take a look at these &lt;a href=&quot;https://pbs.twimg.com/media/CxXdzXgVIAA_Cpn.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;images&lt;/a&gt;. This is done by solving an &quot;inverse problem&quot;, i.e., you have some observations and you're trying to estimate what parameters in a (physics-based) model can reproduce the observations. In essence, it is an optimization problem like curve fitting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: Besides InSAR data, we can also use data from seismometers but the former makes it rather obvious.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="6093" LastEditDate="2016-12-30T20:24:45.240" LastActivityDate="2016-12-30T20:24:45.240" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9173" PostTypeId="2" ParentId="9157" CreationDate="2016-11-22T13:21:34.143" Score="5" Body="&lt;p&gt;As a non-climate specialist, this topic is on the edge of my understanding of meteorology, but here are some papers that I found potentially relevant to your topic. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a quote from the summary of &lt;a href=&quot;http://journals.ametsoc.org/doi/full/10.1175/1520-0442%282000%29013%3C4414:WMAMOC%3E2.0.CO%3B2&quot; rel=&quot;noreferrer&quot;&gt;Limpasuvan and Hartmann, 1999&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The planetary wave propagation characteristics can be used to link&#xA;  changes in the tropospheric annular mode to changes in the strength of&#xA;  the stratospheric polar vortex during winter. Planetary waves are&#xA;  strongly attracted to polar regions during the low phase of the&#xA;  annular mode when the tropospheric westerlies are displaced&#xA;  equatorward. We should expect a weaker stratospheric polar vortex&#xA;  then, since planetary waves weaken the polar vortex by generating&#xA;  irreversible mixing.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And here is a quote from &lt;a href=&quot;http://journals.ametsoc.org/doi/full/10.1175/2010JAS3608.1&quot; rel=&quot;noreferrer&quot;&gt;Shepherd and McLandress, 2011&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In particular, the tropospheric warming that is robustly expected from&#xA;  climate change leads to a strengthening of the upper flanks of the&#xA;  subtropical jets, which causes the critical layers on the equatorward&#xA;  side of the jets to move upward, and with them the Rossby wave drag,&#xA;  allowing more Rossby wave activity to penetrate into the subtropical&#xA;  lower stratosphere (Figs. 4, 5). Because the subtropics represent the&#xA;  critical region for wave driving of the Brewer–Dobson circulation, the&#xA;  circulation is thereby strengthened.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So my conclusion from these two papers (there is obviously a lot more detail in the full text) is that polar vortex will weaken, subtropical jets and Brewer-Dobson circulation will strengthen, and Rossby waves will penetrate farther south. Of note, neither paper seemed (to me) to indicate that a cooler stratosphere was predicted. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-11-22T13:21:34.143" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9174" PostTypeId="2" ParentId="9113" CreationDate="2016-11-22T16:10:11.797" Score="2" Body="&lt;p&gt;Great question!&lt;br&gt;&#xA;First, let's look at typical data: here are the 1981-2010 &lt;a href=&quot;http://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis.derived.pressure.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reanalysis&lt;/a&gt; mean and standard deviation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fW8cf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fW8cf.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/TkgyE.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TkgyE.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So looks like the mean 500 height in September for Wisconsin ranges from about 571-580 Dm, with a standard deviation of 36-42 Dm.  These are mean pressures, not lows or highs, so already, not that far off your low.  If (&lt;a href=&quot;http://www.sjsu.edu/faculty/watkins/normalvariation.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;a big if&lt;/a&gt;) meteorological statistics are normally distributed, using this &lt;a href=&quot;http://onlinestatbook.com/2/calculators/normal_dist.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;calculator&lt;/a&gt;, this would suggest a 560 Dm height would be in about the 29th-40th percentile, depending upon location.  A little lower than usual, but apparently fairly typical.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And just for good measure, looking back at the &lt;a href=&quot;http://weather.uwyo.edu/upperair/uamap.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;University of Wyoming&lt;/a&gt;, I was able to fairly quickly come upon:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ehqkf.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ehqkf.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A 554 or 555 Dm low.  If you want to look for more images (perhaps even the event you are reading about), you could also look in the Pix directory for the dates of interest at Iowa State's &lt;a href=&quot;http://mtarchive.geol.iastate.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;MTArchive&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But it appears that 560 Dm would be a fairly typical height for a low/trough during early fall.  Some people might still call it deep (30 Dm of contours on that plot from September would be fair), but it's nothing too abnormal.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2016-11-22T16:10:11.797" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9175" PostTypeId="2" ParentId="8565" CreationDate="2016-11-22T17:25:58.660" Score="1" Body="&lt;p&gt;From &lt;a href=&quot;http://digital.csic.es/bitstream/10261/52596/1/Sabine_Science-2004.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sabine, et al., 2004&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The capacity for ocean waters to take up anthropogenic CO&lt;sub&gt;2&lt;/sub&gt; from the&#xA;  atmosphere is inversely proportional to the value of the Revelle&#xA;  Factor, hence the lower the Revelle Factor, the higher the oceanic&#xA;  equilibrium  concentration of anthropogenic CO&lt;sub&gt;2&lt;/sub&gt; for a given&#xA;  atmospheric CO&lt;sub&gt;2&lt;/sub&gt; perturbation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Revelle_factor&quot; rel=&quot;nofollow noreferrer&quot;&gt;Revelle Factor&lt;/a&gt; is, &quot;the ratio of instantaneous change in carbon dioxide to the change in total dissolved inorganic carbon (DIC)&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, the controlling factor for CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; absorption in seawater is presence of DIC and buffering. If you add CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; and a relatively small portion of it becomes other DIC species such as HCO&lt;span class=&quot;math-container&quot;&gt;$_3^{-}$&lt;/span&gt; or CO&lt;span class=&quot;math-container&quot;&gt;$_3^{2-}$&lt;/span&gt;, then you have a low Revelle factor and high uptake of atmospheric CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;. Alkaline waters (lower pH) can absorb more CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; because they have less of the acidic CO&lt;span class=&quot;math-container&quot;&gt;$_3^{2-}$&lt;/span&gt; and neutral buffering HCO&lt;span class=&quot;math-container&quot;&gt;$_3^{-}$&lt;/span&gt;. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="2470" LastEditDate="2020-05-07T13:40:19.720" LastActivityDate="2020-05-07T13:40:19.720" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="9176" PostTypeId="1" AcceptedAnswerId="9213" CreationDate="2016-11-22T20:16:27.347" Score="12" ViewCount="406" Body="&lt;p&gt;I'm interested in knowing which type of wave a tsunami is, in a strictly mathematical sense.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm gonna cite from &lt;a href=&quot;https://en.wikipedia.org/wiki/Tsunami&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt; for this:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;As the tsunami approaches the coast and the waters become shallow, wave shoaling compresses the wave and its speed decreases below 80 kilometres per hour (50 mph). Its wavelength diminishes to less than 20 kilometres (12 mi) and its amplitude grows enormously – in accord with Green's law.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and also&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Except for the very largest tsunamis, the approaching wave does not break, but rather appears like a fast-moving tidal bore.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;While the first property strongly hints at a tsunami being a shallow water wave, the latter fact, namely that they usually don't break would rather suggest for the tsunami being a &lt;a href=&quot;https://en.wikipedia.org/wiki/Soliton&quot; rel=&quot;noreferrer&quot;&gt;soliton-solution&lt;/a&gt; of a Korteveeg-de-Vries-type equation.&lt;br&gt;&#xA;I thought the latter property would not be inherent to shallow water waves although &lt;a href=&quot;https://en.wikipedia.org/wiki/Shallow_water_equations&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia, again&lt;/a&gt; seems to argue differently, however only with a picture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So maybe someone can clarify:  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Which equations govern the surface profile of a tsunami? Has this model been tested against satellite measurments?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="489" LastActivityDate="2017-02-28T04:24:49.480" Title="Tsunami - Mathematical classification" Tags="|tsunami|solitary-waves|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="9177" PostTypeId="1" AcceptedAnswerId="9178" CreationDate="2016-11-22T21:35:55.233" Score="3" ViewCount="193" Body="&lt;p&gt;If the convergent boundary is only consuming 10mm of oceanic crust per year, it &quot;seems&quot; like that would provide insufficient material to cause the level of eruption generally observed. I am making the assumption that it is the consumed oceanic crust that is ejected from the volcano as molten lava. It is probably more complex than that.&lt;/p&gt;&#xA;" OwnerUserId="7027" LastActivityDate="2016-11-22T22:58:09.807" Title="How does 10mm/yr of plate subduction provide enough material to create eruptions?" Tags="|plate-tectonics|subduction|volcanic-eruption|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9178" PostTypeId="2" ParentId="9177" CreationDate="2016-11-22T22:44:25.117" Score="4" Body="&lt;p&gt;Yes, the situation is much more complex than you make out - the generation of melt is typically caused by partial melting of the mantle wedge located beneath the volcanic arc. This process is mainly affected by the trench geometry (flat or steeply dipping slab), the local geotherm, and volatile content (water, gases etc.) of the slab or subducted material.&#xA;You're neglecting the total volume of the plate being subducted, as there is an along-trench length of the plate, as well as the thickness of the slab. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When it comes to amount of melt generated, the localisation and upwelling of melt from the mantle wedge isn't fully understood - so it is hard to determine how many volcanic centres will be fed from the material.&lt;/p&gt;&#xA;" OwnerUserId="7028" LastEditorUserId="7028" LastEditDate="2016-11-22T22:58:09.807" LastActivityDate="2016-11-22T22:58:09.807" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9179" PostTypeId="2" ParentId="9177" CreationDate="2016-11-22T22:45:32.640" Score="2" Body="&lt;p&gt;10mm a year is a huge volume when you multiply with lithosphere thickness and length of the boundary, but you are right - it's more complex than this. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Melting is caused by the interplay of temperature, pressure and chemical composition. In the case of subduction of oceanic crust, it's the mainly the water that have been incorporated in seafloor that lowers the melting temperature and expands when reaching a the temperature and pressure of a critical depth. As it can only expand upwards, magma chambers are formed and eventually erupts as volcanos. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The largest volumes of lava are however formed by other mechanisms. The volume of material is not directly related to the impact of the eruption, again the chemical composition is the main factor (Silica content in this case).&lt;/p&gt;&#xA;" OwnerUserId="2536" LastActivityDate="2016-11-22T22:45:32.640" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9180" PostTypeId="1" AcceptedAnswerId="9182" CreationDate="2016-11-23T02:47:51.423" Score="6" ViewCount="121" Body="&lt;p&gt;The image below is included in the BBC article &lt;a href=&quot;http://www.bbc.com/news/uk-scotland-highlands-islands-38063662&quot; rel=&quot;noreferrer&quot;&gt;Amazing white rainbow snapped over Scottish moor&lt;/a&gt;. Apparently this phenomenon is sometimes called a &quot;fog-bow&quot; and is characterized by the washing out of perceived color relative to a conventional rainbow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this related to the geometry (fog being far closer to the viewer) or properties of the droplets themselves? If so, which properties and why? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Higher resolution in &lt;a href=&quot;https://www.flickr.com/photos/melvin_nicholson/30770612090/&quot; rel=&quot;noreferrer&quot;&gt;flickr&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/B14NB.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/B14NB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2019-08-18T15:17:58.927" LastActivityDate="2019-08-18T15:17:58.927" Title="What actually happens to reduce the perceived color in a 'white rainbow&quot; or &quot;fog-bow&quot;?" Tags="|light|atmospheric-optics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9181" PostTypeId="1" CreationDate="2016-11-23T04:24:28.967" Score="4" ViewCount="108" Body="&lt;p&gt;In the ScienceAlert article &quot;&lt;a href=&quot;http://www.sciencealert.com/new-estimates-suggest-the-big-one-in-san-andreas-could-be-much-worse-than-we-thought&quot; rel=&quot;nofollow noreferrer&quot;&gt;New estimates suggest the 'big one' in San Andreas could be much worse than we thought&lt;/a&gt;&quot; they make the claim that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Researchers have forecast a mega-quake running the entirety of the San Andreas fault line in California&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A major mechanism suggested for this quake is the &quot;creeping zone&quot; of the fault, which is defined in the article as:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The &quot;creeping section&quot; of the San Andreas fault that Page refers to above is a 153-km (95-mile) stretch that bridges the northern and southern segments of the fault.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The article reports that recent modelling has determined that it was possible (just not all that probable) that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Seismic activity in this creeping section could help trigger a much larger earthquake, enabling a major quake originating on either side to span the north-south divide.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Researching further (as I know better than to trust news sources), in the USGS publication that the article was based on, &quot;&lt;a href=&quot;http://pubs.usgs.gov/of/2013/1165/pdf/ofr2013-1165.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Uniform California Earthquake Rupture Forecast,&#xA;Version 3 (UCERF3)—The Time-Independent Model&lt;/a&gt;&quot;, it is still not entirely clear as to how the 'creeping section' of the San Andreas Fault could cause this mega-quake. Hence the question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What specifically changed in our understanding of the seismicity of the 'creeping section' to claim that it could be a mechanism for a San Andreas megaquake?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;I would not be surprised if it is related to the research going on behind &lt;a href=&quot;https://earthscience.stackexchange.com/q/9078/7009&quot;&gt;simultaneous and near-simultaneous earthquakes&lt;/a&gt; in general&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user7009" LastEditorUserId="-1" LastEditorDisplayName="user7009" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2017-02-25T09:33:41.697" Title="What is the plausability/legitimacy of the San Andreas Fault 'Big One' Megaquake mechanism?" Tags="|earthquakes|models|predictability|seismic-hazards|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9182" PostTypeId="2" ParentId="9180" CreationDate="2016-11-23T12:55:21.173" Score="7" Body="&lt;p&gt;The reason why &lt;a href=&quot;https://en.wikipedia.org/wiki/Fog_bow&quot; rel=&quot;noreferrer&quot;&gt;fog bows&lt;/a&gt; lack colour, compared to rainbows, is due to the size of the drops of water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fog is composed of very small drops of water - less than 0.05 mm diameter. Because of this the wavelength of light is critical, with diffraction smearing out colours that the larger drops of water in a rainbow would make.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-11-23T12:55:21.173" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9183" PostTypeId="1" CreationDate="2016-11-23T17:11:38.633" Score="5" ViewCount="818" Body="&lt;p&gt;I have been observing a nepheline specimen under polarized light and found some interesting places. I have taken several images. The first shows a micro-geode with parallel polarizers, second with crossed polarizers. I wonder.. could these crystals inside be nepheline ? If not, what mineral could it be ? The thin section was labelled &quot;nepheline&quot;. Also.. is the bubble real air bubble or anything else ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Parallel polarizers:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/e9x2j.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/e9x2j.jpg&quot; alt=&quot;Image with parallel polarizers&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.flickr.com/photos/violetplanet/30883853122/in/album-72157671897003403/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.flickr.com/photos/violetplanet/30883853122/in/album-72157671897003403/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Crossed polarizers:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/6CIIA.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6CIIA.jpg&quot; alt=&quot;Image with crossed polarizers&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.flickr.com/photos/violetplanet/30883853562/in/album-72157671897003403/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.flickr.com/photos/violetplanet/30883853562/in/album-72157671897003403/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have also observed pyroxene crystals in Fe-solution (in parallel nicols could be mistaken with biotite), olivine and there should be nepheline. I have also found secondary quartz filling a cavity near olivine crystals. I    believe the original rock was some kind of basalt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for help.&lt;/p&gt;&#xA;" OwnerUserId="7031" LastEditorUserId="534" LastEditDate="2016-11-24T01:18:02.023" LastActivityDate="2016-11-24T01:18:02.023" Title="I have found this structure in thin section. What is it?" Tags="|geology|mineralogy|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="9184" PostTypeId="1" CreationDate="2016-11-23T22:06:25.997" Score="3" ViewCount="104" Body="&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1038/nclimate3036&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tokarska et al. (2016)&lt;/a&gt;, a &lt;em&gt;Nature&lt;/em&gt; article from a team of the University of Victoria, predicted a global temperature increase of 7&amp;plusmn;2.5°C and 17.2&amp;plusmn;2.5°C at the equator and at the poles respectively if all proven fossil carbon resources are burned (about 5 trillion tons of carbon).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would be the sea level rise with this temperature?&lt;/p&gt;&#xA;" OwnerUserId="7032" LastEditorUserId="28050" LastEditDate="2019-05-13T21:48:00.220" LastActivityDate="2019-05-13T21:48:44.003" Title="What would be the sea level rise if all fossil fuel resources are burned?" Tags="|climate-change|sea-level|climate-models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="9185" PostTypeId="1" CreationDate="2016-11-23T22:13:04.640" Score="3" ViewCount="1548" Body="&lt;p&gt;Suppose a planet like Earth or Venus is totally isolated from sunlight. How quick would it cool down?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On Earth it seems to me that the air temperature drops significantly even during a night. Does it mean that if we screen Venus of Sun's radiation with some untransparent cloud, it would cool down rather quickly, and not for millions of years as some may expect?&lt;/p&gt;&#xA;" OwnerUserId="2819" LastActivityDate="2016-11-25T00:37:07.907" Title="How long it takes to cool a planet?" Tags="|atmosphere|temperature|planetary-science|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9186" PostTypeId="2" ParentId="9185" CreationDate="2016-11-23T22:45:59.437" Score="3" Body="&lt;p&gt;Not a full answer as that is hard to give.  But:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a diagram by Kevin Trenberth picturing energy flows in the Earth climate system:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bky1b.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bky1b.png&quot; alt=&quot;Energy flows&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;(Source: &lt;a href=&quot;http://www.skepticalscience.com/Tracking_Earths_Energy.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Skeptical Science&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the hypothetical extreme case of blocking all incoming solar radiation, the Earth would — initially — have a net heat loss of roughly 340 $W m^{-2}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;93% of net radiation change on Earth enters the oceans.  In the past 20 years, this has led to an increase in ocean heat content (OHC) of roughly $10^{23}$ J.  With a 340 W m^{-2} heat loss, undoing that would take $10^{23} J / ((340 W/m^2) * .7 * 510 * 10^6 km^2$ which is roughly 10 days.  Although this is a severe oversimplification, it does give us a first order of magnitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It might be possible to run a climate model and switch off the Sun, &lt;em&gt;just for fun&lt;/em&gt;.  You don't need a heavy climate model to do so.  &lt;a href=&quot;http://edilbert.github.io/PLASIM/&quot; rel=&quot;nofollow noreferrer&quot;&gt;PlaSim&lt;/a&gt; is good enough to get a handle on it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My guesstimate is that it would take a couple of months before mid-latitude oceans start to freeze.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/leKps.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/leKps.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;(Source: &lt;a href=&quot;https://www.epa.gov/climate-indicators/climate-change-indicators-ocean-heat&quot; rel=&quot;nofollow noreferrer&quot;&gt;EPA&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2016-11-23T22:45:59.437" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9187" PostTypeId="1" CreationDate="2016-11-23T23:06:58.000" Score="4" ViewCount="78" Body="&lt;p&gt;I have access to rock core(s) and vacuum saturation chambers as seen in the image below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/z4vly.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/z4vly.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can dry the rock core using an oven, measure its geometry and mass.  I can place it into the vacuum saturation chamber and allow the liquid to spontaneously imbibe (or wick) its way up and through the rock.  What, if any, are the various measurement(s) and testing procedure(s) I can perform with regards to this process that would provide me information about the rock?  For example, pore-throat size, tortuosity, pore-size distribution, porosity, permeability, etcetera.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assume I can make all sorts of measurements.  For example, I could measure the height of the free-liquid surface that is allowed into the vacuum saturation chamber, the height of the imbibed liquid as a function of time, the vacuum pressure as a function of time (or hold it constant), etcetera.&lt;/p&gt;&#xA;" OwnerUserId="538" LastActivityDate="2016-11-23T23:06:58.000" Title="Capillary rise experiment and obtainable information about the porous medium" Tags="|geophysics|hydrology|measurements|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9188" PostTypeId="2" ParentId="9184" CreationDate="2016-11-23T23:32:51.097" Score="1" Body="&lt;p&gt;At the upper end of that range, all ice on Earth would melt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That would &lt;em&gt;ultimately&lt;/em&gt; give roughly 70 metre sea level rise from melting ice alone, but it may take thousands of years before it reaches equilibrium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Add a bit to that to account for the thermal expansion of sea water.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="28050" LastEditDate="2019-05-13T21:48:44.003" LastActivityDate="2019-05-13T21:48:44.003" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="9192" PostTypeId="1" AcceptedAnswerId="9200" CreationDate="2016-11-24T12:28:10.993" Score="8" ViewCount="248" Body="&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt; Two new items may shed more light on this question:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;BBC: &lt;a href=&quot;http://www.bbc.com/news/science-environment-42183077&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gravity signals rapidly show true size of giant quakes&lt;/a&gt; links to:&lt;/li&gt;&#xA;&lt;li&gt;Science: &lt;a href=&quot;http://science.sciencemag.org/content/358/6367/1164&quot; rel=&quot;nofollow noreferrer&quot;&gt;Observations and modeling of the elastogravity signals preceding direct seismic waves&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The Nature Communications paper &lt;a href=&quot;http://www.nature.com/articles/ncomms13349&quot; rel=&quot;nofollow noreferrer&quot;&gt;Prompt gravity signal induced by the 2011 Tohoku-Oki earthquake&lt;/a&gt; presents a &quot;...report on the search for a prompt gravity signal during the rupture of the 2011 Mw 9.0 Tohoku-Oki earthquake in data recorded by a superconducting gravimeter in the underground Kamioka Observatory and five nearby broadband seismometers from the Japanese network F-net.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They conclude that with a certainty of about 99% that a prompt gravity signal was detected. The change in position of large masses of crust resulted in a tiny change in gravity even 500 km away and this was within detectable limits of this extremely sensitive instrument.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since gravity's influence &quot;travels&quot; at the speed of light it is suggested this might be an avenue to be explored for a potential early warning system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Considering that electrical and optical signals (e.g. the internet or radio or a more dedicated communications system) travel about 2/3 the speed of light in wires and fiber, and even conventional internet pings are of the order of 100 milliseconds or better, &lt;em&gt;is there any suggestion or discussion anywhere else besides this paper&lt;/em&gt; that super-sensitive gravimeters would be in any way better and/or cheaper than a network of cheap sensors? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In either case the idea is an early warning for something &quot;big&quot; rather than accurate measurements. Although the paper and analysis is interesting and elegant - is there any serious discussion or speculation that something like this - a prompt gravity signal - could somehow be &lt;em&gt;actually useful&lt;/em&gt; as an early warning system?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2019-02-09T04:08:00.867" LastActivityDate="2023-09-20T10:36:48.813" Title="Prompt gravity signal induced by the 2011 Tohoku-Oki earthquake - could this really be useful for warnings?" Tags="|seismology|earthquakes|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="9193" PostTypeId="2" ParentId="7993" CreationDate="2016-11-24T19:23:30.980" Score="7" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Temperature differences y/y are very small compared to natural&#xA;  variation during the year, and the trend we see could be statistical&#xA;  illusion, especially that the scientists who developed the method were&#xA;  looking to demonstrate exactly that sort of trend.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Fortunately statisticians have developed tests to determine whether the evidence for a warming trend is &quot;statistically significant&quot; (i.e. the probability of observing a trend as great as that seen if it was just a statistical illusion is below some pre-determined threshold).  This is basic STATS 101 stuff.  If you pick a trend length above the WMO recommended minimum of 30 years (i.e. a period long enough to expect the trend to be detectable given the noise - in other words the test has reasonable statistical power) then the evidence for a warming trend is indeed statistically significant.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The correlation between CO&lt;sub&gt;2&lt;/sub&gt; emissions and measured temperature changes&#xA;  is not perfect.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Well of course not, because CO&lt;sub&gt;2&lt;/sub&gt; is not the only thing that influences global surface temperatures, for instance volcanic forcing, aerosols, solar forcing etc.  You would only expect a &quot;perfect&quot; correlation if CO&lt;sub&gt;2&lt;/sub&gt; were the only thing affecting GMSTs and there was no &quot;weather noise&quot;, for instance ENSO changing the distribution of heat between the atmosphere and oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ivar has been rather naughty in his diagram, you can get a better visual correlation by rescaling the graphs:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LlrJM.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LlrJM.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sadly &lt;a href=&quot;http://woodfortrees.org/&quot; rel=&quot;noreferrer&quot;&gt;woodfortrees.org&lt;/a&gt; only has the Mauna Loa data, but you get the idea, if someone is claiming that the correlation isn't very good and don't plot the data in a way that maximises the apparent correlation, then that should ring alarm bells!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suspect the correlation with total heat content (dominated by ocean heat content) is likely to be rather better (as increased radiative forcing heats the oceans as well as the atmosphere, so you need to consider them both together).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hB9fM.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hB9fM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="624" LastEditorUserId="725" LastEditDate="2016-11-26T12:12:07.133" LastActivityDate="2016-11-26T12:12:07.133" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9194" PostTypeId="1" CreationDate="2016-11-25T00:02:48.060" Score="0" ViewCount="71" Body="&lt;p&gt;(a) What, if anything, is the difference between Earths geographic center, &lt;em&gt;i.e.&lt;/em&gt; mid-point of the spin axis, and the gravitational center?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(b) What is the average distance between the Earth's center of gravity, and the Earth-Moon system's center of gravity?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(c) The recent 'super-moon' is a reminder that the moon's distance has an orbital wobble. So, by how much does this vary the distance between the Earth &lt;em&gt;vs&lt;/em&gt; Earth-Moon gravitational centres, and&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(d) Is the moon's varying distance from the Earth sufficient to create any noticeable effect upon sea/ocean tidal amplitudes?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-11-25T15:43:50.330" Title="Musing on Earth's gravity" Tags="|tides|earth-moon|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9196" PostTypeId="2" ParentId="9185" CreationDate="2016-11-25T00:37:07.907" Score="1" Body="&lt;p&gt;The estimate by &quot;gerrit&quot; looks reasonable to me. I'd like to add an estimation of resulting surface temperature based on geothermal flux.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Current surface balance is achieved at about 240W/m2 given current solar irradiation minus albedo. If the Earth will be shielded from Sun, the only source to counter-balance the radiation loss would be the geothermal flux, which is about 0.1W/m2&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How low the surface temperature will drop? The OLR as a function of temperature as sigma*T^4. The ratio between Sun/no-Sun in energy flux is therefore 240/0.1=2400, and this ratio is proportional to (T1/T2)^4. So the temperature should drop by a factor of (2400)^1/4, or about 7 times. Since the equilibrium emission temperature is 255K, the surface temperature will drop to 36-40K in a matter of days, as gerrit estimated, and will stay there for millions of years.&lt;/p&gt;&#xA;" OwnerUserId="6584" LastActivityDate="2016-11-25T00:37:07.907" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9198" PostTypeId="2" ParentId="9194" CreationDate="2016-11-25T15:37:53.297" Score="1" Body="&lt;p&gt;For (a) through (c), consider the differences between the &lt;a href=&quot;http://en.wikipedia.org/wiki/Geoid&quot; rel=&quot;nofollow noreferrer&quot;&gt;geoid&lt;/a&gt; and the reference ellipsoid, in addition to the barycentre.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For (d): A slightly higher &lt;a href=&quot;http://oceanservice.noaa.gov/facts/perigean-spring-tide.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;perigean spring tide&lt;/a&gt; than usual, meaning in some geographical locations perhaps an amplitude difference of inches rather than millimetres.&lt;/p&gt;&#xA;" OwnerUserId="7042" LastEditorUserId="7042" LastEditDate="2016-11-25T15:43:50.330" LastActivityDate="2016-11-25T15:43:50.330" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9199" PostTypeId="2" ParentId="8861" CreationDate="2016-11-25T16:04:08.000" Score="1" Body="&lt;p&gt;From McKenzie's &lt;a href=&quot;http://dx.doi.org/10.1093/petrology/25.3.713&quot; rel=&quot;nofollow noreferrer&quot;&gt;original 1984 paper&lt;/a&gt; and from &lt;a href=&quot;http://dx.doi.org/10.1016/0012-821X(87)90057-4&quot; rel=&quot;nofollow noreferrer&quot;&gt;Spiegelman &amp;amp; McKenzie (1987)&lt;/a&gt; paper the equations that govern the conservation of momentum and mass of a low-viscosity fluid melt (magma) in a deformable matrix (rocks) are:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;${\partial\over\partial t} (\rho_f\phi) + \nabla \cdot (\rho_f\phi{\bf v})=\Gamma$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;${\partial\over\partial t} [\rho_s(1-\phi)] + \nabla \cdot [\rho_s(1-\phi){\bf V]}=-\Gamma$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;${\bf v}-{\bf V}=-{k_\phi\over\rho \mu}\nabla \mathscr{P} $&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\nabla \mathscr{P}=\eta\nabla^2{\bf V}+(\zeta+{\eta\over3})\nabla(\nabla\cdot{\bf V})+(1-\phi)\Delta\rho g\hat k $&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$k_\phi \sim \alpha^2{\phi^n\over c} $&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\rho_f$ is the density of the magma, $\phi$ is the porosity or the volume fraction occupied by the magma, ${\bf v}$ is the magma velocity, $\Gamma$ is the &quot;melting function&quot;, which gives the rate of mass transfer from matrix to magma, $\rho_s$ is the density of the solid matrix, ${\bf V}$ is the matrix velocity, $k_\phi$, is the permeability, $\mathscr{P}$ is the piezometric pressure (the pressure in excess of hydrostatic pressure, $\mathscr{P}=P-\rho_fgz$), $\Delta\rho=\rho_s-\rho_f$ and $\hat k$ is the unit vector in the $z$ direction with $z$ increasing downwards. The permeability, $k_\phi$, can be expressed as a non-linear function of the grain size $\alpha$, porosity, and a dimensionless coefficient, $c$. &lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2016-11-25T16:04:08.000" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9200" PostTypeId="2" ParentId="9192" CreationDate="2016-11-25T23:51:24.097" Score="5" Body="&lt;p&gt;If you have a sufficient number of sensors, e.g., land-based or ocean-bottom seismometers, in the vicinity of where strong earthquakes typically happen, then it will take a few seconds for seismic waves to reach them, and a few hundred milliseconds for the electric signal to get to a place where a warning could be triggered.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, the gravimeter would provide essentially instant warning. So you save a few seconds. At the same time, it takes many many seconds for earthquake waves to travel to the places where the warning would matter. In fact, the earthquake rupture itself may be many many seconds long. And it will take minutes for tsunamis to reach shore. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, what you gain in advance warning time is not actually very large, and it may not be worth the effort. I would also not be surprised if it takes tens of seconds or minutes to actually see the change in gravity in noisy gravity measurements, and/or to take the same amount of time to just process the data.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2016-11-25T23:51:24.097" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9201" PostTypeId="2" ParentId="9149" CreationDate="2016-11-26T02:25:25.343" Score="2" Body="&lt;p&gt;The atmosphere has various layers.  Going upwards they are - troposphere, stratosphere, mesosphere, thermosphere, exosphere. (There are &quot;pause&quot; layers between, like tropopause, stratopause etc.) The density gets less and less and the exact height to the top of the exosphere is difficult to determine because the gas is so thin. However, we normally talk about the height of the troposphere which varies from about 7 to 10 km at the poles to about 18 km above the Equator. The reason it is higher at the Equator has to do partly with centrifugal force being greater there. For example, if a jelly-like sphere is rotated it starts to bulge outwards in the central, faster moving region.  Even the solid Earth itself bulges at the Equator due to centrifugal force.  See &lt;a href=&quot;https://tallbloke.wordpress.com/2012/09/16/why-is-the-troposphere-8km-higher-at-the-equator-than-the-poles/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this blog post for details&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="7035" LastEditorUserId="5594" LastEditDate="2016-11-28T16:46:49.710" LastActivityDate="2016-11-28T16:46:49.710" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9204" PostTypeId="1" AcceptedAnswerId="9207" CreationDate="2016-11-26T10:00:55.333" Score="3" ViewCount="1112" Body="&lt;p&gt;I have been looking around at this topic recently, and it seems that it is relatively easy to determine the age of young water, by testing the concentration of anthropogenic contaminants. However, I've also heard about scientists determining the age of water as being &gt;60 years old. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How exactly is this done, and how accurate is it?&lt;/p&gt;&#xA;" OwnerUserId="7047" LastActivityDate="2017-05-23T11:48:19.447" Title="How do you determine the age of &gt;60 year old water?" Tags="|water|groundwater|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9205" PostTypeId="2" ParentId="4240" CreationDate="2016-11-26T11:58:15.393" Score="2" Body="&lt;p&gt;There doesn't seem to be central reference for standard temperature and atmospheric pressure at high altitudes. Below is the code I wrote after combining two resources that can be found in the comments. This C++ code calculates standard atmospheric pressure all the way up to 86km.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;  float getStandardPressure(float altitude /* meters */)   //return Pa&#xA;  {&#xA;    //Below 51km: Practical Meteorology by Roland Stull, pg 12&#xA;    //Above 51km: http://www.braeunig.us/space/atmmodel.htm&#xA;    //Validation data: https://www.avs.org/AVS/files/c7/c7edaedb-95b2-438f-adfb-36de54f87b9e.pdf&#xA;&#xA;    altitude = altitude / 1000.0f;  //convert meters to km&#xA;    float geopot_height = getGeopotential(altitude);&#xA;&#xA;    float t = getStandardTemperature(geopot_height);&#xA;&#xA;    if (geopot_height &amp;lt;= 11)&#xA;      return  101325 * pow(288.15f / t, -5.255877f);&#xA;    else if (geopot_height &amp;lt;= 20)&#xA;      return 22632.06 * exp(-0.1577f * (geopot_height - 11));&#xA;    else if (geopot_height &amp;lt;= 32)&#xA;      return 5474.889f * pow(216.65f / t, 34.16319f);&#xA;    else if (geopot_height &amp;lt;= 47)&#xA;      return 868.0187f * pow(228.65f / t, 12.2011f);&#xA;    else if (geopot_height &amp;lt;= 51)&#xA;      return 110.9063f * exp(-0.1262f * (geopot_height - 47));&#xA;    else if (geopot_height &amp;lt;= 71)&#xA;      return 66.93887f * pow(270.65f / t, -12.2011f);&#xA;    else if (geopot_height &amp;lt;= 84.85)&#xA;      return 3.956420f * pow(214.65f / t, -17.0816f);&#xA;&#xA;    throw std::out_of_range(&quot;altitude must be less than 86km. Space domain is not supported yet!&quot;);    &#xA;  }&#xA;&#xA;  //geopot_height = earth_radius * altitude / (earth_radius + altitude) /// all in kilometers&#xA;  //temperature is in Kelvin = 273.15 + celcius&#xA;  float getStandardTemperature(float geopot_height) &#xA;  {&#xA;    //standard atmospheric pressure&#xA;    //Below 51km: Practical Meteorology by Roland Stull, pg 12&#xA;    //Above 51km: http://www.braeunig.us/space/atmmodel.htm&#xA;    if (geopot_height &amp;lt;= 11)          //troposphere&#xA;      return 288.15f - (6.5 * geopot_height);&#xA;    else if (geopot_height &amp;lt;= 20)     //Staroshere starts&#xA;      return 216.65f;&#xA;    else if (geopot_height &amp;lt;= 32)&#xA;      return 196.65f + geopot_height;&#xA;    else if (geopot_height &amp;lt;= 47)       &#xA;      return 228.65f + 2.8 * (geopot_height - 32);&#xA;    else if (geopot_height &amp;lt;= 51)     //Mesosphere starts&#xA;      return 270.65f;&#xA;    else if (geopot_height &amp;lt;= 71)       &#xA;      return 270.65f - 2.8 * (geopot_height - 51);&#xA;    else if (geopot_height &amp;lt;= 84.85)    &#xA;      return 214.65f - 2 * (geopot_height - 71);    &#xA;    //Thermospehere has high kinetic temperature (500c to 2000c) but temperature&#xA;    //as measured by thermometer would be very low because of almost vaccume&#xA;    throw std::out_of_range(&quot;geopot_height must be less than 85km. Space domain is not supported yet!&quot;);&#xA;  }&#xA;&#xA;  float getGeopotential(float altitude_km)&#xA;  {&#xA;    constexpr float EARTH_RADIUS =  6356.766; //km&#xA;    return EARTH_RADIUS * altitude_km / (EARTH_RADIUS + altitude_km);&#xA;  }&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="7049" LastActivityDate="2016-11-26T11:58:15.393" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9207" PostTypeId="2" ParentId="9204" CreationDate="2016-11-26T21:06:34.933" Score="6" Body="&lt;p&gt;According to this pdf: &lt;a href=&quot;http://www.iup.uni-heidelberg.de/institut/forschung/groups/aquasys/WAH/lehre/material/Archive_V07_h.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Physikalische Grundlagen der Klimaarchive Eis und Grundwasser&lt;/a&gt; (mostly German - some English) all methods to determine the age of groundwater bodies older than ~60 years are radiometric:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;39&lt;/sup&gt;Ar: 30 yr - 2000 yr&lt;br&gt;&#xA;&lt;sup&gt;14&lt;/sup&gt;C: 1,000 yr - 30,000 yr&lt;br&gt;&#xA;&lt;sup&gt;36&lt;/sup&gt;Cl: 100,000 yr - 1,000,000 yr&lt;br&gt;&#xA;&lt;sup&gt;81&lt;/sup&gt;Kr: 100,000 yr - 1,000,000 yr&lt;br&gt;&#xA;&lt;sup&gt;40&lt;/sup&gt;Ar: 100,000 yr - &gt;10,000,000 yr&lt;br&gt;&#xA;&lt;sup&gt;4&lt;/sup&gt;He: 10 yr - &gt;10,000,000 yr&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another &lt;a href=&quot;http://www.spektrum.de/lexikon/geowissenschaften/grundwasser-altersbestimmung/6431&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt; (german only) also mentions &lt;sup&gt;32&lt;/sup&gt;Si with a similar range as &lt;sup&gt;39&lt;/sup&gt;Ar.&lt;/p&gt;&#xA;" OwnerUserId="5282" LastEditorUserId="5282" LastEditDate="2017-05-23T11:48:19.447" LastActivityDate="2017-05-23T11:48:19.447" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9208" PostTypeId="2" ParentId="9204" CreationDate="2016-11-27T03:00:27.120" Score="5" Body="&lt;p&gt;&lt;em&gt;Klanomath&lt;/em&gt; is technically correct regarding &lt;em&gt;natural&lt;/em&gt; radionuclides, although in practical terms it is only radiocarbon and 36-Cl that are used to date water. Tritium, from atom bomb tests in the 1950s and 1960s used to be used, but the concentration has now decayed to levels indistinguishable from background. In some parts of the world other radionuclides such as 137-Cs from Chernobyl, can still be traced in the water. In about 40 years from now it will be possible to distinguish between pre- and post-60 year old water on the basis of the dates from which certain pesticides were banned. Similarly, in 50 years time we will be able to distinguish pre- and post- ban of CFCs. Most of the non-radiogenic indicators will be in vanishingly small quantities, typically in parts per trillion, or less, so will require pre-ultra-concentration of large water samples, and will be horribly expensive to analyze. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-11-27T03:00:27.120" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9209" PostTypeId="2" ParentId="9005" CreationDate="2016-11-27T03:15:31.357" Score="1" Body="&lt;p&gt;It's difficult for non specialists to understand the heat build-up in the Earth. Handle a specimen of uranium or thorium ore, which is just as radioactive as the Earth's interior, and you will not notice any heat from the rock. The rate of heat emission from radioactive decay is minute, but is real and continues for billions of years. The reason why the core of the Earth is as hot as the sun's surface is that the radiogenic heat has nowhere to go. It is effectively locked in by a thermal insulating blanket thousands of kilometres thick - &lt;em&gt;i.e.&lt;/em&gt; the mantle. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Studies of neutrino sources indicate that 54% of the Earth's current internal heat comes from radioactive decay, the remaining 46% being primordial heat, presumably from initial gravitational condensation from the solar nebular. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-11-27T03:15:31.357" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9210" PostTypeId="1" AcceptedAnswerId="9223" CreationDate="2016-11-27T03:23:51.817" Score="9" ViewCount="900" Body="&lt;p&gt;Without the sun to keep the Earth's temperature topped up to something comfortable, what would be the equilibrium surface temperature range. It would obviously be a balance between outgoing radiation and geothermal conduction to the surface. This question is prompted by Anixx's recent question on planetary cooling time without the sun. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2016-11-27T09:20:45.323" LastActivityDate="2016-12-07T10:36:36.363" Title="What is the current equilibrium surface temperature of Earth, i.e. without the sun?" Tags="|geothermal-heat|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9211" PostTypeId="1" AcceptedAnswerId="9212" CreationDate="2016-11-27T12:44:53.973" Score="5" ViewCount="3867" Body="&lt;p&gt;I have read that the edges of the tectonic plates exist at places like: huge mountains and sea trenches, and I wondered if they exist at the mid-oceanic ridges?&lt;/p&gt;&#xA;" OwnerUserId="6908" LastEditorUserId="2470" LastEditDate="2016-11-27T13:11:36.257" LastActivityDate="2018-10-25T02:47:41.680" Title="The edges of the tectonic plates" Tags="|plate-tectonics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9212" PostTypeId="2" ParentId="9211" CreationDate="2016-11-27T13:26:02.700" Score="6" Body="&lt;p&gt;The short answer is &lt;strong&gt;yes&lt;/strong&gt;, the edges (boundaries) of &lt;a href=&quot;https://en.wikipedia.org/wiki/Plate_tectonics&quot; rel=&quot;noreferrer&quot;&gt;tectonic plates&lt;/a&gt; do occur at the mid-oceanic ridges, such as the Mid-Atlantic ridge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are three types of tectonic plate boundaries:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Transform Boundaries&lt;/strong&gt; where the plates slide past each other sideways, such as at the &lt;a href=&quot;https://en.wikipedia.org/wiki/San_Andreas_Fault&quot; rel=&quot;noreferrer&quot;&gt;San Andreas Fault&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Divergent Boundaries&lt;/strong&gt; where the plates are moving apart, such as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mid-Atlantic_Ridge&quot; rel=&quot;noreferrer&quot;&gt;Mid-Atlantic Ridge&lt;/a&gt;  and the &lt;a href=&quot;https://en.wikipedia.org/wiki/East_African_Rift&quot; rel=&quot;noreferrer&quot;&gt;East African Rift&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Convergent Boundaries&lt;/strong&gt; where one plate slides beneath the other plate, such as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Andes&quot; rel=&quot;noreferrer&quot;&gt;Andes&lt;/a&gt; mountain range &amp;amp; the Japanese &lt;a href=&quot;https://en.wikipedia.org/wiki/Island_arc&quot; rel=&quot;noreferrer&quot;&gt;island&#xA;arc&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-11-27T13:26:02.700" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9213" PostTypeId="2" ParentId="9176" CreationDate="2016-11-27T18:01:07.650" Score="8" Body="&lt;p&gt;Short answer: Tsunami models use the shallow-wave mathematical approach, because their wavelength is usually much larger than the relevant water depth determining their propagation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Long answer:&#xA;Tsunamis are often called 'tidal waves' to highlight the idea that their characteristic time response is closer to tydes than to the standard wind waves we are used to see in a beach. The full spectrum of water wave periods is shown in this figure (tsunamis being classified as long-period waves, together with waves caused by meteorological events):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/NzQn4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NzQn4.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;Classification of the spectrum of ocean waves according to wave period. Redrawn from Figure 1 in: Walter H. Munk (1950) &quot;Origin and generation of waves&quot;. Proceedings 1st International Conference on Coastal Engineering, Long Beach, California. ASCE, pp. 1–4.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This image shows that the wave frequency depends on the cause behind the perturbation of the water surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oceanographers generally treat ocean waves as free surface waves in an ideal fluid [&lt;a href=&quot;http://ms.mcmaster.ca/craig/PASI-VI-2_JDDE1133.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;]. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mathematically, tsunamis are surface gravity waves approached as &lt;strong&gt;shallow-water waves&lt;/strong&gt; (see chapter 4.1.5 in &lt;a href=&quot;https://engineering.dartmouth.edu/~d30345d/books/EFM/chap4.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;), meaning that the wavelength &lt;strong&gt;λ &gt; 20H&lt;/strong&gt; (H being the water depth). The involved shallow-water-wave mathematical approximations oppose to the deep-water waves (λ &amp;lt; H, see section 4.1.4 in the same [ref &lt;a href=&quot;https://engineering.dartmouth.edu/~d30345d/books/EFM/chap4.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;]). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whereas for shallow waves the wave frequency and the wave speed are (ref. &lt;a href=&quot;https://engineering.dartmouth.edu/~d30345d/books/EFM/chap4.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$ω = \sqrt {g k 2H}$    with $k = 2\pi / \lambda$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$c = \sqrt {g H}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;for deep-water waves, instead:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$ω = \sqrt {g k}$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$c = \sqrt {\frac{g \lambda}{2\pi}}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the wave approaches the shore and H decreases, the wave velocity decreases and energy is preserved by increasing the wave amplitude.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Detailed information here: &lt;a href=&quot;https://engineering.dartmouth.edu/~d30345d/books/EFM/chap4.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="1379" LastEditorUserId="-1" LastEditDate="2017-02-28T04:24:49.480" LastActivityDate="2017-02-28T04:24:49.480" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9215" PostTypeId="2" ParentId="9204" CreationDate="2016-11-28T21:32:59.273" Score="3" Body="&lt;p&gt;The 'age' of groundwater is typically taken to mean the time since the water became isolated from the atmosphere. Tritium is still be used since it is produced in the atmosphere in small amounts and it can be measured by low-level counting or by the ingrowth of its decay product He-3. The half life of tritium is ~ 12.3 years so it is good for young groundwater. I don't know why the article states a large range for He-4. I expect it is a mash-up of He-3 ingrowth from tritium decay and the subsurface production of He-4 from alpha decay of heavy radioactive elements (an alpha particle is a He-4 nucleus). Thus it can be used to estimate age of very old water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Argon-39 would be very useful in age dating groundwater but there are currently only about 3 labs in the world who can measure it and radioactive counting needs a large volume of water. The atom-trapping method is still in early stages of development. That method will be a big breakthrough for krypton, too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Chlorine-36 is produced in the atmosphere and at low levels in the subsurface, which complicates its use. It is also produced in nuclear reactors and by atomic bombs. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The methods can be very accurate but you have to understand and account for the different sources and reactions that can affect the measurements.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2016-11-28T21:32:59.273" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9216" PostTypeId="1" CreationDate="2016-11-28T23:54:47.687" Score="3" ViewCount="2126" Body="&lt;p&gt;When I take a look at weather models, there is an option to take a look at PWAT or QPF. What's the difference?&lt;/p&gt;&#xA;" OwnerUserId="7060" LastActivityDate="2016-11-29T08:25:33.927" Title="What is the difference between Precipitable Water (PW or PWAT) and Quantitive Precipitation Forecast (QPF) in terms of computer weather model data?" Tags="|meteorology|models|water|precipitation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9219" PostTypeId="2" ParentId="9216" CreationDate="2016-11-29T08:25:33.927" Score="4" Body="&lt;p&gt;&lt;a href=&quot;http://en.mimi.hu/meteorology/precipitable_water.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Precipitable water&lt;/strong&gt;&lt;/a&gt; is the total amount of moisture throughout the air (the total in the entire tropospheric air &quot;column&quot;; most moisture is found in the lowest few km, due to decreases in temperature and density and where humidity sources being at the ground).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whereas &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Quantitative_precipitation_forecast&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;QPF&lt;/strong&gt;&lt;/a&gt; is the amount of precipitation that has fallen or is predicted to fall in a certain period of time (often 6 or 24 hours).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Generally more moisture (higher PWATs) do indicate the potential for more precipitation.  But you could definitely have a large PWAT and get no rain/snow/etc to fall from the sky.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I believe the greatest PWAT values are typically found in the warm saturated columns near tropical cyclones (hurricanes/typhoons).  From experience, in the US South, PWATs near/above 2 inches are generally considered quite large in the summer, and tend to indicate a greater chance of rain from air mass/sea breeze/frontal storms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whereas hourly rainfall rates can often be nearer 3-5 inches per hour, and locations can report over 20 inches of rain in a day&lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_weather_records#Rain&quot; rel=&quot;nofollow noreferrer&quot;&gt; [rainfall records]&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2016-11-29T08:25:33.927" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9220" PostTypeId="1" CreationDate="2016-11-29T15:06:11.967" Score="2" ViewCount="273" Body="&lt;p&gt;Are there any mineral identification techniques that work for all minerals(non-metallic/metallic), so that an electronic device could be made to distinguish between all minerals?&lt;/p&gt;&#xA;" OwnerUserId="7010" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T11:53:33.497" LastActivityDate="2019-08-29T11:53:33.497" Title="Is there any mineral identification techniques that works for all minerals?" Tags="|geology|mineralogy|minerals|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="9222" PostTypeId="1" AcceptedAnswerId="9227" CreationDate="2016-11-29T19:02:30.240" Score="3" ViewCount="145" Body="&lt;p&gt;Assume a 1m per century sea level rise. Looking at a &lt;a href=&quot;http://geology.com/sea-level-rise/&quot; rel=&quot;nofollow noreferrer&quot;&gt;topographic map&lt;/a&gt; it quicly becomes clear that Bengal, the Netherlands, the lower Mississippi, South American Mesopotamia, etc will all soon be underwater. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which rivers, if any, deposit sediment in their deltas or mouths fast enough to counteract a 1m per century rise in sea level?&lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-11-30T11:21:53.890" Title="Do any rivers deposit sediment in their deltas fast enough to counteract sea level rise?" Tags="|sedimentology|sea-level|rivers|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9223" PostTypeId="2" ParentId="9210" CreationDate="2016-11-29T20:57:59.753" Score="10" Body="&lt;p&gt;Assuming a thermodynamic equilibrium between heat from below and heat escaping into outer space, and assuming an energy from below of 44 to 47 terawatts (the Earth's current internal heat budget), that means the surface temperature would be about 35 or 36 kelvins by the Stefan-Boltzmann law: $$\varepsilon \sigma A T^4 = \phi$$&#xA;where $\varepsilon$ is the surface's emissivity in the thermal range (which I assumed to be one), $\sigma$ is the Stefan-Boltzmann constant (5.670367×10&lt;sup&gt;-8&lt;/sup&gt;  W/M&lt;sup&gt;2&lt;/sup&gt;/K&lt;sup&gt;4&lt;/sup&gt; in SI units) , $A$ is the Earth's surface area, $T$ is the surface temperature, and $\phi$ is the energy supplied to the Earth's surface from below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that atmospheric effects are a non-concern for this very low temperature. The Earth would have no atmosphere except perhaps some trace helium and hydrogen gas.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2016-12-07T10:36:36.363" LastActivityDate="2016-12-07T10:36:36.363" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="9224" PostTypeId="2" ParentId="9220" CreationDate="2016-11-29T21:34:11.957" Score="4" Body="&lt;p&gt;Yes, it is called X-ray diffraction (XRD). It is done by machines that look like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/01kRn.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/01kRn.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not sure this is in the scope of your electronic engineering project.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-11-29T21:34:11.957" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="9225" PostTypeId="1" AcceptedAnswerId="9226" CreationDate="2016-11-30T02:25:25.813" Score="2" ViewCount="150" Body="&lt;p&gt;I  use Carl Schreck's site &lt;a href=&quot;https://ncics.org/portfolio/monitor/mjo/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Equatorial Wave Zoo&lt;/a&gt; for monitoring atmospheric waves such as Kelvin wave, Equatorial Rossby wave, filtered MJO OLR, Mixed Rossby Wave(MRG),etc. &#xA;Here is an example - &lt;a href=&quot;https://pub.cicsnc.org/mjo/v2/map/cfs/olr/global/olr.cfs.kelvin.global.7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kelvin Wave OLR&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition I use Matt Wheeler's BOM site(unavailable at the moment) for the same information. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now I am getting interested in the ocean and it's characteristics as part of my effort in learning coupled models i.e. air - sea models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a site for monitoring equatorial oceanic waves(in real time with lag) such as oceanic Kelvin wave, Rossby wave etc ? That should help me in identifying along the equator at least where upwelling or downwelling is likely to occur. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would prefer a site for my basin i.e. Indian Ocean. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2016-11-30T08:23:49.787" LastActivityDate="2017-09-19T07:43:16.387" Title="Any site for monitoring equatorial oceanic waves?" Tags="|ocean|oceanography|waves|wave-modeling|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9226" PostTypeId="2" ParentId="9225" CreationDate="2016-11-30T09:00:07.160" Score="3" Body="&lt;p&gt;There are a few sea surface height datasets available on &lt;a href=&quot;https://podaac.jpl.nasa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;PO.DAAC&lt;/a&gt; (the Physical Oceanography Distributed Active Archive Center), but this one seems to be (near-)real-time and global: the &lt;a href=&quot;https://podaac.jpl.nasa.gov/dataset/ALTIKA_SARAL_L2_OST_XOGDR?ids=SpatialCoverage&amp;amp;values=Global&amp;amp;search=wave&quot; rel=&quot;nofollow noreferrer&quot;&gt;SARAL Near-Real-Time Value-added Operational Geophysical Data Record Sea Surface Height Anomaly&lt;/a&gt;.&lt;br&gt;&#xA;It was launched in 2013 so there is just 3 years of data so far but it should help I think.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly you have a few current datasets such as the &lt;a href=&quot;https://podaac.jpl.nasa.gov/dataset/OSCAR_L4_OC_1deg?ids=Measurement&amp;amp;values=Ocean%20Circulation&quot; rel=&quot;nofollow noreferrer&quot;&gt;OSCAR 1 degree ocean surface currents&lt;/a&gt; dataset which was launched in 1992. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are all raw datasets though, so you'll have to do the data processing and the plotting yourself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The altimetry data provides a good way of looking at waves. Apart from SARAL, &lt;a href=&quot;http://www.aviso.altimetry.fr/en/data.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;AVISO&lt;/a&gt; provides high quality, remotely sensed, gridded and raw altimetry data.&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2017-09-19T07:43:16.387" LastActivityDate="2017-09-19T07:43:16.387" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9227" PostTypeId="2" ParentId="9222" CreationDate="2016-11-30T11:21:53.890" Score="5" Body="&lt;p&gt;This is a hugely complex subject for which a categorical answer requires detailed river basin modelling and process calibration. The short answer is that in the short term many rivers deposit sediment much more rapidly than the hypothetical 1m per century, because sediment transport is roughly proportional to the fourth power of the stream velocity. So enormously high deposition occurs in the few hours per year of peak discharge. Mean annual deposition, however, is a different issue, and inordinately difficult to measure. A typical mean rate of sedimentary deposition is roughly 2 to 3 mm per year +/- at least an order of magnitude. This is slightly less than the current mean rate of sea-level rise, but remembering that the rate of sea-level rise is accelerating, and is likely to continue accelerating well into the next century. Projected rates of sea level rise by 2100 are tricky to estimate (too many unknowns) but &gt;10 mm/year seems likely, in which case probably no significant rivers will be able to compensate by high sediment deposition. There will be occasional anomalies, such as the rivers around Mount Pinatubo in the Philippines, which had jaw-dropping sediment loads for the few years after the volcano erupted, caused by huge quantities of un-cemented volcanic ash over entire catchments, coupled with typhoon rainfall. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case of really big rivers with perennially high sediment loads, one thinks of the Mekong and the Ganges-Meghna-Brahmaputra, both of which have huge monsoonal sediment fluxes. Both river systems have pro-graded their deltas surprisingly recently. Check out their delta areas on Google Earth. All of that sediment was deposited during the last 6000 years. During most of that time, sea level rise seems to have been very modest, averaging about 1.5 to 2.5 mm/year.&lt;br&gt;&#xA;Since you pose a climate-change related rate of sea level rise, one must also consider how climate change will affect the hydrologic response of these catchments, and hence how the rate of sedimentation will change? Even with a three-year research grant I would be hard-pressed to answer that question, but my suspicion is that sea-level rise will win, and most of the major deltas will succumb to the waves.   &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-11-30T11:21:53.890" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9228" PostTypeId="2" ParentId="7033" CreationDate="2016-11-30T22:16:28.883" Score="2" Body="&lt;p&gt;By midpoint range he refers to the size (length in the crossline direction) of the area in the subsurface that is illuminated by one pass of the boat. In a simple case of flat and parallel layers, that range is half of the size of the &quot;spread&quot; or receiver patch. BTW, this is true both in inline or crossline directions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;By coverage he means how the subsurface is illuminated by the combination of many passes of the patch over the area of a 3D survey. In common practice, passes are overlapped in the surface by half the crossline size of the patch so that the areas of subsurface illumination are contiguous with no overlap.&lt;/p&gt;&#xA;" OwnerUserId="7070" LastEditorUserId="725" LastEditDate="2016-12-01T01:52:48.210" LastActivityDate="2016-12-01T01:52:48.210" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9229" PostTypeId="1" CreationDate="2016-12-01T00:32:13.383" Score="1" ViewCount="148" Body="&lt;p&gt;The news tells us that global carbon emissions are now more or less constant, as in the 2014-16 data points of &lt;a href=&quot;http://arstechnica.com/science/2016/11/global-carbon-emissions-look-steady-for-third-year-running/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global carbon emissions flatline continues&lt;/a&gt;.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/89Yiy.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/89Yiy.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;On the other hand, the Keeling graph of mean global CO2 keeps climbing upwards. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/CGDbr.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CGDbr.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;So clearly there is some feedback which continues to put CO2 into the atmosphere, for at least 3 years after the emissions plateau. What is the source of this feedback? Is it one dominant process or a multitude of lesser feedbacks?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="6093" LastEditDate="2016-12-01T08:43:59.627" LastActivityDate="2016-12-06T11:02:31.657" Title="Atmospheric Carbon: Whence the discrepancy?" Tags="|climate-change|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9231" PostTypeId="2" ParentId="9229" CreationDate="2016-12-01T09:18:53.080" Score="6" Body="&lt;p&gt;There's no discrepancy here.  The first graph (total emissions from fossil fuels and industry; Fig. 4a of &lt;a href=&quot;http://dx.doi.org/10.5194/essd-8-605-2016&quot; rel=&quot;nofollow noreferrer&quot;&gt;Le Quéré et al, 2016&lt;/a&gt;) is an input to the system, and the second graph is a proxy for the amount stored in one part of the system (the atmosphere).  For the latter, it probably makes more sense to look at the total atmospheric growth rate (Fig. 4c of Le Quéré et al), which has remained positive for decades.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that when you add in emissions from land-use it's likely that the total emissions have continued to increase.  But that doesn't detract from the main point here: if you keep putting stuff in the bucket, the amount in the bucket will continue to increase.  You don't need to invoke any feedbacks for that to happen.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2016-12-01T09:18:53.080" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9232" PostTypeId="1" CreationDate="2016-12-01T17:06:36.600" Score="3" ViewCount="997" Body="&lt;p&gt;The decline of the large population centers around the eastern Mediterranean at the end of the Bronze Age has been associated with a set of large earthquakes (&quot;earthquake storm&quot;) occurring between 1300 BCE and 1150 BCE (e.g., &lt;a href=&quot;http://www.academia.edu/3810687/Tracking_earthquake_archaeological_evidence_in_Late_Minoan_IIIB_c._1300-1200_BC_Crete_Greece_a_proof_of_concept&quot; rel=&quot;nofollow noreferrer&quot;&gt;late Minoan Crete Earthquakes&lt;/a&gt;). What evidence is there of such events? How can they explain the collapse of these civilizations?&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="725" LastEditDate="2016-12-19T01:12:37.817" LastActivityDate="2016-12-19T01:12:37.817" Title="Evidence for &quot;earthquake storm&quot; at the end of the Bronze Age" Tags="|earthquakes|seismic-hazards|history|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9233" PostTypeId="1" AcceptedAnswerId="9236" CreationDate="2016-12-01T21:07:50.240" Score="5" ViewCount="477" Body="&lt;p&gt;Is it possible to find pleochroic halos in muscovite ? I would have said that it must be biotite (also, in PPL it is brown!), but then.. why does it have interference colors so similar to muscovite ? Or is it anything else ? Thanks for help !&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;PPL&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QdQlY.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QdQlY.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In high resolution here: &lt;a href=&quot;https://www.flickr.com/photos/violetplanet/30947378580/in/album-72157671897003403/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Biotite with pleochroic halos (30 µm thin section, XPL)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;XPL&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jHtfK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jHtfK.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In high resolution here: &lt;a href=&quot;https://www.flickr.com/photos/violetplanet/31315634545/in/album-72157671897003403/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Biotite with pleochroic halos (30 µm thin section, XPL)&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="7031" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T09:15:04.980" LastActivityDate="2019-08-29T09:15:04.980" Title="Muscovite with pleochroic halos?" Tags="|geology|mineralogy|minerals|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="9234" PostTypeId="2" ParentId="7056" CreationDate="2016-12-01T23:40:18.983" Score="12" Body="&lt;p&gt;Skype.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Skype someone at least 10 time zones away. Ask them to point the camera at the sky.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Proven.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This actually works really well for a psychological reason as well. Its easy to deny abstract arguments, its difficult talking to someone and denying what they claim is their experience.&lt;/p&gt;&#xA;" OwnerUserId="7081" LastActivityDate="2016-12-01T23:40:18.983" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9235" PostTypeId="2" ParentId="9149" CreationDate="2016-12-01T23:46:10.550" Score="1" Body="&lt;p&gt;The atmosphere, as a whole, is approximately in hydrostatic equilibrium. This means that the gravity of the earth holds the atmosphere to the earth, preventing its escape, though few molecules may escape every so often.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mathematically, this can be described by $$\frac{dP}{dr}=-\rho g$$ where P is the pressure, $\rho$ is the density, and $g$ is gravity. Using the Ideal Gas Law $$P=\rho R T$$, where $T$ is temperature and $R$ is the gas constant for air. Assuming that the temperature in the height of a column of the atmosphere is averaged ($\bar{T}$) an equation for the average height of the atmosphere can be found $$P(r,\phi,\lambda)=P_0(\phi,\lambda)exp(-\frac{(r-r_0)g}{R\bar{T}(\phi,\lambda)})=P_0(\phi,\lambda)exp(-\frac{gz}{R\bar{T}(\phi,\lambda)})$$&#xA;where $r_0$ is the radius of the earth,$P_0$ is the surface pressure, $r=z+r_0$, where $z$ is the height above the earth's surface, $\phi$ is the latitude, and $\lambda$ is the longitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To Summarize:&#xA;As the average temperature of the atmosphere increases, the height of the atmosphere will generally increase. This means that the height of the atmosphere will generally be the lowest near the poles, but highest near the equator. There are certainly exceptions to this rule, but this generally works. If you were to go around the equator, it will likely not be a &quot;perfect circle&quot; since the average temperature would have to be exactly the same.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2016-12-01T23:46:10.550" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9236" PostTypeId="2" ParentId="9233" CreationDate="2016-12-02T03:48:16.960" Score="2" Body="&lt;p&gt;One doesn't see pleochroic haloes in muscovite, I suspect because the crystal lattice of muscovite isn't conducive to developing inclusions of allanite and other radioactive minerals. I suggest you measure the 2V- to distinguish between muscovite and the paler varieties of biotite. Note that the more magnesian-rich varieties of biotite, &lt;em&gt;i.e.&lt;/em&gt; phlogopite, can be very pale brown in PPL. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't attach much credence to interference colours because the range of colours in muscovite and phlogopite overlap, and can appear very similar. Also, slightly coloured crystals tend to mask the interference colours, so it may be difficult to judge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One may ask 'why pleochroic haloes in biotite, but not in muscovite?', as in 2-mica schist. I can't prove it, but it is known that uranium adsorbs onto Fe-rich surfaces of the biotite, so my hypothesis is that adsorbed uranium serves as crystallization foci for adjacent allanite crystalls, which are then enclosed as inclusions as the biotite crystal continues to grow. You won't see this in muscovite because of the absence of Fe.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is curious that inclusions of magnetite can occur in muscovite, but not radioactive mineral inclusions - at least, not that I have ever seen. I don't know why. Anyone else have any ideas on this?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-12-02T03:48:16.960" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9237" PostTypeId="2" ParentId="9233" CreationDate="2016-12-02T04:28:16.500" Score="6" Body="&lt;p&gt;It's biotite. Not muscovite. That's why you have the pleochroic halos in it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't understand why you are saying that the interference colours are like muscovite. First of all, the lack of cleavage suggests you are looking down (or close to) the x axis, so this means the interference colours you see are going to be very low. Let's say 1st order white or brown. And then, it's going to get the anomalous brown colour of the biotite together with it, which is exactly what you see here. Also, muscovite is not brown in ppl. This one is. Therefore, it's biotite.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2016-12-06T06:16:06.913" LastActivityDate="2016-12-06T06:16:06.913" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9238" PostTypeId="1" AcceptedAnswerId="9252" CreationDate="2016-12-02T04:16:05.263" Score="8" ViewCount="1731" Body="&lt;p&gt;Given several hundred years, assuming global climate change results in the melting of the polar ice caps which leads to an increase in surface area of the oceans and an overall warming of the earth (although I'm not quite certain to what extent the earth as a whole could increase in temperature in several hundred years), would the result be an increased amount of evaporated water into the air increasing the overall humidity?&lt;/p&gt;&#xA;" OwnerUserId="7083" OwnerDisplayName="Kim" LastEditorUserId="7083" LastEditDate="2016-12-02T10:49:32.117" LastActivityDate="2019-07-08T03:54:18.387" Title="Could Global Climate Change increase the average moisture in the air?" Tags="|meteorology|climate-change|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9239" PostTypeId="5" CreationDate="2016-12-02T11:46:10.127" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2016-12-02T11:46:10.127" LastActivityDate="2016-12-02T11:46:10.127" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9240" PostTypeId="4" CreationDate="2016-12-02T11:46:10.127" Score="0" Body="In contrast to the short-term variable weather, climate describes the mean conditions of atmosphere. Thus it is the statistic of weather (mean values, extrema, etc.). Often a 30-year period is considered.&#xD;&#xA;When asking questions about climate, use this tag and also include the [atmosphere] tag. " OwnerUserId="6441" LastEditorUserId="6441" LastEditDate="2016-12-02T15:44:45.280" LastActivityDate="2016-12-02T15:44:45.280" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9241" PostTypeId="2" ParentId="9238" CreationDate="2016-12-02T11:56:51.053" Score="5" Body="&lt;p&gt;Out of the total water on Earth, only a tiny fraction is held in the atmosphere at any given time.  Therefore, the direct effect of melting land or sea ice will not result in an increase in specific humidity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;However&lt;/em&gt;, warm air can contain more water than cold air, according to the Clausius-Clapeyron equation.  Therefore, the climate warming that causes the ice caps to melt, will also result in an increase in average specific humidity.  This is (approximately) an exponential relation (I don't have access to my textbooks right now, but googling &lt;em&gt;saturation vapour pressure water equation&lt;/em&gt; yields many forms; I do not include them here because none I found use SI units).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9GNQ2.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9GNQ2.gif&quot; alt=&quot;Saturation vapour pressure of water&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;Saturation vapour pressure of water.  &lt;a href=&quot;http://www.chemguide.co.uk/physical/phaseeqia/vapourpress.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source: Chemguide&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See also the (not very good) Wikipedia article on &lt;a href=&quot;https://en.wikipedia.org/wiki/Vapour_pressure_of_water&quot; rel=&quot;nofollow noreferrer&quot;&gt;Vapour pressure of water&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2016-12-02T12:08:06.503" LastActivityDate="2016-12-02T12:08:06.503" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9243" PostTypeId="2" ParentId="8650" CreationDate="2016-12-02T19:14:12.020" Score="1" Body="&lt;p&gt;There are several references to refraction tools in the Wikipedia page for free geophysics software:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Comparison_of_free_geophysics_software&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Comparison_of_free_geophysics_software&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7070" LastActivityDate="2016-12-02T19:14:12.020" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9244" PostTypeId="1" CreationDate="2016-12-02T20:15:06.227" Score="6" ViewCount="352" Body="&lt;p&gt;I have some geologic well data. The lithologies have been interpreted, and stratigraphic columns have been drawn. The columns have been adjusted for elevation, and correlation has been done between seemingly continuous layers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a more sophisticated 2D/3D program, preferably open source or free trial (I'm a student), that could be used to map the area better with an interpolated or block diagram result?&lt;/p&gt;&#xA;" OwnerUserId="7087" LastEditorUserId="7596" LastEditDate="2017-03-06T19:43:15.403" LastActivityDate="2017-03-07T03:59:42.653" Title="Methods and Software for Interpolating/Modelling of Stratigraphic Well Data in 2D/3D" Tags="|geology|models|stratigraphy|software|data-analysis|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9246" PostTypeId="1" CreationDate="2016-12-03T23:10:09.267" Score="7" ViewCount="1833" Body="&lt;p&gt;If most of jet streams are westerly, that is to say, they blow from west to east, why does the tropical/equatorial jet stream blow from east to west?&lt;/p&gt;&#xA;" OwnerUserId="7090" LastEditorDisplayName="user1066" LastEditDate="2019-03-01T16:32:37.827" LastActivityDate="2020-01-27T01:53:40.280" Title="Easterly Jet Stream" Tags="|meteorology|climatology|jet-stream|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9247" PostTypeId="2" ParentId="9246" CreationDate="2016-12-04T06:10:34.807" Score="8" Body="&lt;p&gt;Looking at the annual climatology of the 200 hPa winds as shown below from NCAR NCEP reanalysis it is noted that the mid latitudes have by and large westerly winds (for a planet that rotates west to east). On the other hand averaged over a latitude circle(zonal average) the low latitude tropics and equator have by and large easterly winds. The reference &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/1520-0442%281993%29006%3C0932%3AACOEEW%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Annual cycle of equatorial east-west circulation over the Indian and Pacific Oceans&lt;/a&gt; argues that tropical upper level divergence over the Central Pacific is the reason for the upper level equatorial easterlies present over the Indian Ocean and West Pacific Ocean. On the other hand annual mean upper level equatorial winds over the East Pacific and east Atlantic are by and large westerlies(if one were to perform zonal regional averaging). &#xA;&lt;a href=&quot;https://i.stack.imgur.com/0Bt92.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0Bt92.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The upper level equatorial easterlies never quite approach the definition of a &quot;jet&quot; on annual scales except during the boreal summer period. So one needs to look at seasonal scales to explain the formation of the so called &lt;strong&gt;Tropical Easterly Jet Stream&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From these two pioneering papers &lt;a href=&quot;http://www.tellusa.net/index.php/tellusa/article/viewFile/9220/10832&quot; rel=&quot;nofollow noreferrer&quot;&gt;Koteswaram TEJ &lt;/a&gt; and &lt;a href=&quot;http://link.springer.com/article/10.1007/BF00876576&quot; rel=&quot;nofollow noreferrer&quot;&gt;Raghavan K TEJ 1973&lt;/a&gt; (available behind a paywall, reproduced here - &lt;a href=&quot;http://www.tropmet.res.in/~lip/Publication/RR-pdf/RR-06.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Origin of Tropical Easterly Jet&lt;/a&gt;), there exists at the upper levels an anticyclone over the Indian subcontinent, also known as the Tibetan anticyclone. The Tropical Easterly Jet(TEJ) is believed to be connected with the Tibetan &lt;a href=&quot;https://en.wikipedia.org/wiki/Anticyclone&quot; rel=&quot;nofollow noreferrer&quot;&gt;anticyclone&lt;/a&gt;. The Tibetan anticyclone is present in the upper troposphere (100 to 150 hPa). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0pfR1.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0pfR1.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the above image derived from NCEP NCAR reanalysis data the June through September climatology of the 100 hPa geopotential height is presented and one can clearly see the Tibetan anticyclone as part of the broader monsoon anticyclone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the location of the Tibetan anticyclone is in accordance with seasonal shifts. In winter the Tibetan anticyclone is further south (around 10 N) and during summer it moves to warmer latitudes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lower levels of the anticyclone is tilted equatorward during the boreal summer and poleward during the winter. However the upper levels of the anticyclone are tilted poleward during all seasons. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Koteswaran and Raghavan have calculated the zonal component of the equatorward outflow from the anticyclone and there appears to be no comparison with the upper level easterlies associated with the Indian Summer Monsoon(&lt;a href=&quot;https://earthscience.stackexchange.com/questions/4427/climatology-of-the-indian-summer-monsoon-a-modern-consensus/4436#4436&quot;&gt;ISM&lt;/a&gt;). But there appears to be strong comparison with the winds derived from thermal gradient over the Tibetan Plateau. &lt;strong&gt;So it appears that the winds are originating due to thermal reasons alone&lt;/strong&gt;. The TEJ is to a large extent influenced by the temperature distribution in the upper levels as a result of vertical motion associated with ISM. The Tibetan plateau comes under the influence of both sensible and latent heat and leading to the formation of a &lt;a href=&quot;https://en.wikipedia.org/wiki/Thermal_low&quot; rel=&quot;nofollow noreferrer&quot;&gt;surface heat low&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given  the climatology of the observed surface pressure(this surface pressure has &lt;strong&gt;not&lt;/strong&gt; been extrapolated to sea level pressure) during the June through September period this data indicates that the mean value is around 500 hPa it might be helpful to look at the temperature of the 500 hPa climatology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/I2q6t.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/I2q6t.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/F0ThE.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/F0ThE.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why should one want to look at the 500 hPa temperature surface ? it is because 500 hPa is the average surface pressure over the Tibetan Plateau(which is an elevated plateau). Normally the 500 hPa pressure surface over sea levels is found at a height of 5 kms.&#xA;Once again one can clearly see from the 500 hPa temperature surface that the Tibetan plateau provides for an elevated heat source. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Krishnamurti in the book &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/0471874167&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Monsoon Models&lt;/a&gt; offers a detailed explanation &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the southerly outflow of the subtropical jet provides a mechanism where eddy kinetic energy is converted into kinetic energy of the mean flow and all this happens above 250 hPa. Stratospheric easterly winds penetrate downwards into the northern branch of the TEJ. Above all the conversion of available potential energy into kinetic energy above 250 hPa in the region of increasing pressure gradient caused by the proximity of the Tibetan anticyclone as well as the Coriolis force convert the diabatic heat into kinetic energy of the TEJ. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QGV5w.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QGV5w.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The above image provides a visual representation of the explanation provided in the quoted text i.e. southerly outflow of subtropical jet + Coriolis force.  &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2020-01-27T01:12:11.020" LastActivityDate="2020-01-27T01:12:11.020" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="9248" PostTypeId="2" ParentId="9238" CreationDate="2016-12-04T09:23:40.857" Score="1" Body="&lt;p&gt;The short answer is yes but, as &lt;a href=&quot;https://van.physics.illinois.edu/qa/listing.php?id=1440&quot; rel=&quot;nofollow noreferrer&quot;&gt;this blog post&lt;/a&gt; indicates, there are many factors and variables involved. In the absence of wind and any variation in pressure, evaporation will increase with both temperature and any increase in the temperature difference between the water surface and the air. However, as the air approaches 100% relative humidity the rate of net evaporation decreases because there is increasing condensation. When 100% relative humidity is reached the evaporation and condensation balance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An interesting consequence is that, if it were true that radiation from increasing water vapor were actually raising the surface temperature (and increasing evaporation) then the whole globe would end up being at 100% relative humidity and we could expect continuous hail, rain or snow everywhere. Fortunately, we can use the laws of physics as in &lt;a href=&quot;https://papers.ssrn.com/sol3/papers.cfm?abstract_id=2876905&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt; to understand why an increase in water vapor will actually lower the surface temperature and increase that in the upper troposphere so as to make the temperature gradient (aka lapse rate) less in magnitude, whilst maintaining radiative balance between the incident solar radiation and the outward radiation. There is also a study in the Appendix of that 2013 paper of mine which confirms this physics in that it shows that more moist regions have lower mean temperatures than drier regions at similar latitude and altitude. Hence there will not be any runaway warming effect due to increasing evaporation and levels of water vapor.&lt;/p&gt;&#xA;" OwnerUserId="7035" LastActivityDate="2016-12-04T09:23:40.857" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9249" PostTypeId="1" AcceptedAnswerId="9251" CreationDate="2016-12-04T20:23:55.410" Score="0" ViewCount="1102" Body="&lt;p&gt;For this other question &lt;a href=&quot;https://engineering.stackexchange.com/questions/12650/would-this-chambered-cylinder-be-possible&quot;&gt;&quot;Would this chambered cylinder be possible&quot;&lt;/a&gt;, preferably near the equator where is a calmest place from the troposphere to the stratosphere where is the windless place one Earth most of the year?&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="-1" LastEditDate="2017-04-13T12:51:48.770" LastActivityDate="2016-12-05T12:22:50.970" Title="Other than the South Pole where is the windless place on Earth?" Tags="|atmosphere|wind|geography|troposphere|stratosphere|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9250" PostTypeId="2" ParentId="9249" CreationDate="2016-12-04T21:20:38.697" Score="3" Body="&lt;p&gt;Truth be told, there is no such place. The atmosphere is a fluid, and a fluid moves. If a fluid did not move, it would not be a fluid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Proof of concept- If you exhale, the carbon dioxide, water vapor, and other materials that form your breath would need to move, otherwise you would asphyxiate. That movement can be classified as wind, therefore wind exists. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Concerning the reference to your other question, there is no such a location. Consider the surface. Usually we assume the surface is fixed, which is fine over solid land. Because of this, there must be drag on the atmosphere. This drag slows the wind down. Since the air closest to the ground is slower than the air a bit further from the ground, there must be shear. Therefore shear is unavoidable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For this entire monologue, I have spoken only on the small scales. It is worth noting that on the larger scales, that your linked question is true. A feature of &lt;a href=&quot;https://en.wikipedia.org/wiki/Geostrophic_wind&quot; rel=&quot;nofollow noreferrer&quot;&gt;geostrophic theory&lt;/a&gt; is the existence of &lt;a href=&quot;https://www.youtube.com/watch?v=7NI5snKZaXE&quot; rel=&quot;nofollow noreferrer&quot;&gt;Taylor columns&lt;/a&gt;. The Great Red Spot on Jupiter can be considered an example of such a Taylor Column &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469(1969)026%3C0744%3AITCAJG%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Ingersoll 1969)&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2016-12-04T21:20:38.697" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9251" PostTypeId="2" ParentId="9249" CreationDate="2016-12-05T02:04:27.070" Score="1" Body="&lt;p&gt;Not just the south pole, but 'Ridge A' and many other parts of the high Antarctic Plateau, at or about 4000 metres altitude, are generally recognized as being the least windy. Otherwise, there are a many parts of the high pressure belts at about +/- 30 degrees which have little wind for most of the year. These tend to be very dry deserts where occasional winds have momentum from other regions. On a local scale there are some deep valleys in tropical rain forests. Once you get below the canopy turbulence level they seldom receive winds of any significance - just the lightest breeze from  impeded convection. However, records are hard to find because anemometers in such locations are not really representative of anything. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is an &lt;a href=&quot;https://www.instagram.com/p/BC1wYF5n3lj/&quot; rel=&quot;nofollow noreferrer&quot;&gt;instagram&lt;/a&gt; which claims that Fern tree bus stop, in Hobart, Tasmania, is the 'calmest place on Earth'.&#xA;But my experience of Hobart is that icy winds in winter can be far from calm. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These things are relative. Compared to the 2100 km/hour winds of Neptune, everywhere on our planet is as close to windless as makes no difference. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="5594" LastEditDate="2016-12-05T12:22:50.970" LastActivityDate="2016-12-05T12:22:50.970" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9252" PostTypeId="2" ParentId="9238" CreationDate="2016-12-05T03:38:20.593" Score="4" Body="&lt;p&gt;Just to clarify, there's 3 distinct &lt;a href=&quot;https://en.wikipedia.org/wiki/Humidity&quot; rel=&quot;nofollow noreferrer&quot;&gt;humidity measurements&lt;/a&gt;, &lt;a href=&quot;http://hyperphysics.phy-astr.gsu.edu/hbase/Kinetic/relhum.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;relative&lt;/a&gt;, which is the one we commonly get on weather reports, often just called humidity, &lt;a href=&quot;http://info.zehnderamerica.com/blog/absolute-vs.-relative-humidity-whats-the-difference&quot; rel=&quot;nofollow noreferrer&quot;&gt;absolute&lt;/a&gt; and &lt;a href=&quot;https://www.britannica.com/science/specific-humidity&quot; rel=&quot;nofollow noreferrer&quot;&gt;specific&lt;/a&gt; humidity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Relative humidity is relative to temperature and is listed as a percentage of the dew point at that temperature (0%-100%), though in rare instances, greater than 100% humidity can happen.  That's a supersaturation event, but it does happen occasionally.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Specific humidity and Absolute humidity aren't temperature dependent and are more similar, but not precisely the same.  Specific has to do with the mass ratio of water vapor to air and Absolute humidity has to do with the water content per volume of air.  Water vapor can also be measured in PPM, but that's essentially a straight multiple of specific humidity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Warmer air should lead to an increase in specific and absolute humidity simply because warmer air holds more water vapor and water can evaporate water more quickly in higher temperature, though other factors like wind speed and sunlight may play a bigger role in evaporation than temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Warmer air shouldn't lead to an increase in relative humidity, in fact, due to expected expanding dry areas and decreased snow run-off, and a decline in plant transpiration in a higher CO2 environment, warmer temperatures should probably lead to a decrease in relative humidity over land on average.   Over oceans and near large bodies of water, relative humidity should stay about constant but as oceans rise, ocean surface area will increase somewhat and land area will shrink.  Because relative humidity is higher over oceans, that will have an increase in the global average.   Overall, the global average for relative humidity should rise in some locations, fall in others and over the globe, stay roughly about the same as temperatures rise.  Specific humidity and absolute humidity would be expected to increase.  (I looked, but couldn't find a specific study or article to back this up), but it's basic logic that warmer air over oceans will contain more water and oceans cover 70% of earth, so it's quite logical that specific and absolute humidity will increase with temperature globally.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a more &lt;a href=&quot;https://www.skepticalscience.com/humidity-global-warming.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;detailed discussion&lt;/a&gt; on this if interested.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Average relative humidity over land varies quite a bit.  Notice the cold regions and regions over rain forests tend towards high humidity.  Climate change may increase the lighter areas of lower humidity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/y5xki.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/y5xki.jpg&quot; alt=&quot;https://nelson.wisc.edu/sage/data-and-models/atlas/maps/avgannrh/atl_avgannrh.jpg&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://nelson.wisc.edu/sage/data-and-models/atlas/maps.php?datasetid=53&amp;amp;includerelatedlinks=1&amp;amp;dataset=53&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Humidity over oceans tends to be higher, closer to 100% all the time &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sSZhw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sSZhw.jpg&quot; alt=&quot;http://www.goes-r.gov/users/comet/tropical/textbook_2nd_edition/media/graphics/jul_rel_humidity_static.jpg&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.goes-r.gov/users/comet/tropical/textbook_2nd_edition/print_5.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Average humidity is a relatively strange term.  Dew can only form when 100% humidity is reached, so at night, anywhere that dew forms, 100% humidity is reached, at night, when the air cools.   At mid day when it's hottest, humidity is usually lowest, so on any given day, relative humidity can vary by 50% or more.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, short answer&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;would the result be an increased amount of evaporated water into the&#xA;  air increasing the overall humidity?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Generally and globally speaking, yes on specific and absolute.  No on relative.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;(although I'm not quite certain to what extent the earth as a whole&#xA;  could increase in temperature in several hundred years)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;All the climate models include humidity and cloud formation and they already account for increasing water vapor in the air as they'd be pretty useless if they didn't.   People sometimes say that CO2 is a weak greenhouse gas and water is stronger, and that's true, but Water is everywhere on the Earth and it cycles in and out of the atmosphere on a daily basis, so it's not a driver.   The increase in CO2 is the driver.   CO2 by itself, everything else remaining the same, probably warms the Earth less than 1 degree.   The temperature models that the IPCC puts out include Water vapor and albedo changes in addition to CO2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've never seen a model that estimates temperature in several hundred years.  I found one for a three hundred, see below.  I also think it's unlikely that the icecaps will melt completely as you suggest.  Antarctic ice has remained frozen in warmer temperatures than we're likely to see over the next few hundred years.   Antarctica began to freeze some 30 million years ago in a much warmer earth, where estimates put the Earth at 6-8 degrees warmer than today.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Chart is too big to link here, but may be seen &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/5/5f/All_palaeotemps.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;here.&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source  &lt;a href=&quot;https://en.wikipedia.org/wiki/Geologic_temperature_record#Overall_view&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Greenland ice could melt over hundreds or thousands of years.  Much of Antarctica will probably stay frozen.  Nobody really knows, of-course and accurate predictions of this sort are impossible, but melting of the Greenland glacier over several hundred to, perhaps a few thousand years is reasonably possible where as the Antarctic glacier formed under temperature several degrees warmer globally than the Earth is today and (IMHO) is very unlikely to melt, though it could (and already has) lost some ice around the edges.   I think it should mostly stay intact, except in the most extreme warming scenarios.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This chart below is based on &lt;a href=&quot;https://en.wikipedia.org/wiki/Representative_Concentration_Pathways&quot; rel=&quot;nofollow noreferrer&quot;&gt;RCP forcing&lt;/a&gt; which are estimates for increased watts per square meter.  The chart implies some leveling off before plus 4 degrees C is reached for most scenarios assuming some effort to begin reducing CO2 emissions by 2040 is successful.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lY5ux.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lY5ux.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.easterbrook.ca/steve/2013/10/what-does-the-new-ipcc-report-say-about-climate-change/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The dark shaded area, RCP8.5, assumes very little effort is made to reduce CO2 output past 2100.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="6093" LastEditDate="2016-12-06T14:29:04.267" LastActivityDate="2016-12-06T14:29:04.267" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9254" PostTypeId="2" ParentId="9138" CreationDate="2016-12-05T21:43:15.803" Score="1" Body="&lt;p&gt;The question re  the sequence of events if not already satisfied is well illustrated on geonet showing the triggering of the individual recording stations&lt;/p&gt;&#xA;" OwnerUserId="7101" LastActivityDate="2016-12-05T21:43:15.803" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9255" PostTypeId="1" CreationDate="2016-12-05T21:57:36.497" Score="2" ViewCount="160" Body="&lt;p&gt;First I would like to note that I have only very basic understanding of ecology, biology and paleontology so I can easily miss something very simple.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can envision certain ways marine and terrestrial ecosystems influence each other:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Rivers and surface runoff carries minerals, soil, plants, excrements etc into the oceans. Productive terrestrial ecosystem would mean less minerals, more organic nutrients going into the ocean.&lt;/li&gt;&#xA;&lt;li&gt;Terrestrial animals (like birds) eat marine ones and then excrete and are eaten at the land.&lt;/li&gt;&#xA;&lt;li&gt;Marine and terrestrial ecosystems absorb and produce atmospheric $O_2$, $CO_2$, $N_2$ that are redistributed globally by atmospheric movements. That also affects climate and therefore water cycle.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Naively it seems to me that the situation is quite asymmetric. While №2 should be of extreme importance to the coastal ecosystems I suppose it's influence drops quickly as you go deeper into continent aggravated by water currents taking everything back into ocean. So (again naively) it seems to me that marine ecosystems should be much more influenced by the terrestrial ones than the other way around.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So imagine sudden significant drop of primary production for some reason constrained to the oceans. Obviously it would be a catastrophe for island and coastal life but in what ways, how much and at what timescale it will affect inland ecosystems? What if we turn it upside down and consider some significant drop of terrestrial primary production?&lt;/p&gt;&#xA;" OwnerUserId="7102" LastEditorUserId="5273" LastEditDate="2016-12-11T10:04:32.320" LastActivityDate="2016-12-11T10:04:32.320" Title="Connections between marine and terrestrial ecosystems" Tags="|oceanography|water|mass-extinction|ecology|land|" AnswerCount="0" CommentCount="5" ClosedDate="2016-12-12T13:28:45.527" ContentLicense="CC BY-SA 3.0" />
  <row Id="9256" PostTypeId="2" ParentId="9244" CreationDate="2016-12-06T03:52:21.283" Score="3" Body="&lt;p&gt;OpendTect &lt;em&gt;may&lt;/em&gt; do this, however getting to that stage would be a painful experience. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Petrel can do this very easily, however, that is not anywhere near free...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you're a student, your department may have access to a few decent programs to achieve this. If you could find out what you have available, we might be of more help!&lt;/p&gt;&#xA;" OwnerUserId="6181" LastActivityDate="2016-12-06T03:52:21.283" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9257" PostTypeId="2" ParentId="9229" CreationDate="2016-12-06T11:02:31.657" Score="2" Body="&lt;p&gt;Atmospheric CO2 rises because more CO2 is being put into the atmosphere than is being taken out.  The airborne fraction (the proportion of cumulative carbon dioxide emissions from anthropogenic sources that remains in the atmosphere) is about 50%, suggesting that total natural uptake &lt;em&gt;currently&lt;/em&gt; exceeds total natural emissions by about half of annual anthropogenic emissions (i.e. about 5GTC per year).  Thus if we keep emitting at a constant rate of 10GTC per year, then atmospheric CO2 will &lt;em&gt;initially&lt;/em&gt; carry on rising by about 5GTC per year, which explains what we see in the second graph, because we will still be emitting more than the natural environment is able to sequester.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, the net natural sink depends on the disequilibrium of CO2 between the atmosphere and the surface ocean (vaguely similar arguments also apply to the terrestrial biosphere), so if we keep emissions constant, then the disequilibrium will be reduced slightly (as the surface ocean absorbs more CO2 than it emits) and so net uptake will start to fall and the airborne fraction will start to rise, however this will take time. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is a bit like putting your foot on the accelerator (gas) in your car.  If you put increasing pressure on the pedal, your car will accelerate.  If you keep it in the same position, you will stop accelerating, but you won't stop moving.&lt;/p&gt;&#xA;" OwnerUserId="624" LastActivityDate="2016-12-06T11:02:31.657" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9258" PostTypeId="1" CreationDate="2016-12-06T12:50:16.520" Score="1" ViewCount="65" Body="&lt;p&gt;I apologize for the lack of foundational knowledge underlying this question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Lightning#Downward_leaders&quot; rel=&quot;nofollow noreferrer&quot;&gt;At wikipedia it is stated&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Initiation of the outward leaders is not well &#xA;  understood. The electric field strength within &#xA;  the thundercloud is not typically large enough &#xA;  to initiate this process by itself.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The above implies that the initiation of outward leaders (and the process by which a charged region of the cloud would cause stepped channels of ionized air to form and branch out towards the earth) would be explicable if the electric field strength within the thundercloud were larger.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is that interpretation of the wikipedia article correct? That is, are the physical processes that lead to the formation of outward leaders well understood, providing a sufficiently strong electric field exists?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly, my understanding is that in CG lightning, the thundercloud contains both negatively and positively charged regions, possibly created by the collision of different types of ice particles within the cloud. Why would it be easier for the region to neutralize its excess charge with the ground, rather than with the far more proximate oppositely charged region of the same thundercloud?&lt;/p&gt;&#xA;" OwnerUserId="7027" LastEditorUserId="5594" LastEditDate="2016-12-06T17:38:36.013" LastActivityDate="2016-12-06T17:38:36.013" Title="What triggers the formation of channels of ionized air for lightning strikes to occur?" Tags="|lightning|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9260" PostTypeId="1" CreationDate="2016-12-06T18:32:07.120" Score="6" ViewCount="1364" Body="&lt;p&gt;I found this beautiful euhedral pyroxene crystal in thin section today. There is one thing that I can´t explain though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oqxaC.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oqxaC.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In crossed polarizers, the crystal shows two different interference colors, which do not change as I rotate the table (no color shifting, no extinction).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HFlka.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HFlka.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as I know, this happens only in basal sections. But then why are there two different interference colors ? Could it be pyroxene twinning ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for all your answers.&lt;/p&gt;&#xA;" OwnerUserId="7031" LastActivityDate="2016-12-06T18:32:07.120" Title="Could this be pyroxene twinning ? (thin section)" Tags="|mineralogy|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9261" PostTypeId="1" AcceptedAnswerId="9283" CreationDate="2016-12-07T03:54:21.997" Score="3" ViewCount="862" Body="&lt;p&gt;I was randomly exploring Google Earth when I came across some sort of rock formation in northern Australia. The location of the rock formation with respect to Australia is shown below. It is in or near Starcke national park.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2Keax.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2Keax.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course it seems absurd (to me) to think a glacier could have existed there anytime even remotely recent in geologic history. But there's a rock formation there that looks like it has been carved up by a glacier. Here's a screenshot of google earth satellite data of the rock formation in question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SSEK6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SSEK6.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Notice the clear distinction between the &quot;carved land&quot; and the vegetation to the south and west, this is one of the traits I find confusing about this structure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried researching the park to see if there is a scientifically accepted origin for this formation, but all I learned is that it is apparently made from sandstone, and the region is noted for being very rugged. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not a geologist, so I might be missing some important info that could help, but I have at least a basic understanding of geology from a few electives I've taken in college. I know that glaciers carve up the land, and when they retreat, they leave behind a mess of jagged rocks and lakes that are aligned in the direction of flow of the former glacier. The above picture seems to show just that: there is a clear sense of direction of the lakes and rocks. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, I was able to find one other similar formation about 400km (~250 miles) north east up the Australian coast (measured as a straight line) near the Sir Charles Hardy Islands. I would show a pic of that as well, but I'm limited because I'm new here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other than these two formations, I was unable to find any other examples. Both formations highly contrast their surroundings and both seem to be &quot;smeared&quot; in roughly the same direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For reference, look closely at the land in northern Canada and Europe, where glaciers are known to have existed geologically recently. (Again, I had pics but I can't post them.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone know how the formation in question was created? If not does anyone have a strong educated guess about what might have caused it? Thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="7108" LastEditorUserId="7108" LastEditDate="2016-12-07T04:39:26.233" LastActivityDate="2023-06-05T09:26:46.270" Title="Was there once a glacier over Starcke national park in Queensland Australia?" Tags="|geology|rocks|planetary-science|glaciology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9262" PostTypeId="1" AcceptedAnswerId="9475" CreationDate="2016-12-07T04:07:22.273" Score="18" ViewCount="821" Body="&lt;p&gt;I've just seen the LiveScience article &lt;a href=&quot;http://www.livescience.com/57109-antarctic-ice-rift-is-70-miles-long.html&quot; rel=&quot;noreferrer&quot;&gt;70-Mile-Long Crack Opens Up in Anatarctica&lt;/a&gt;. I'm not sure if the title is a bit sensational or not, the crack is in an ice shelf, not the continent of Antarctica.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;An ominous crack in an Antarctic ice shelf as wide as a football field is long takes on an otherworldly beauty in a new aerial image.&lt;/p&gt;&#xA;&lt;p&gt;Snapped by scientists on NASA's IceBridge mission, the shot shows a rift in Larsen C, an ice shelf that is floating off the Antarctic Peninsula. When the crack eventually spreads across the entire ice shelf, it will create an iceberg the size of the state of Delaware, according to IceBridge. That's around 2,491 square miles (6,451 square kilometers).&lt;/p&gt;&#xA;&lt;p&gt;As of Nov. 10, when the IceBridge scientists observed this crack, it was 70 miles (112 km) long and more than 300 feet (91 meters) wide. The dark depths of the crack plunge down about a third of a mile (0.5 km), all the way through the ice to the ocean below.&lt;/p&gt;&#xA;&lt;p&gt;[...] Larsen C is Antarctica's fourth-largest ice shelf, and it holds back the land-based glaciers just behind it: Once the ice shelf goes, those slow-flowing glaciers have one less barrier in their journey toward the sea.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;My primary question:&lt;/strong&gt; is this a remarkable event, or something that over time happens regularly? Isn't this just a natural part of &amp;quot;those slow-flowing glaciers... journey toward the sea.&amp;quot; ?&lt;/p&gt;&#xA;&lt;p&gt;I'm also wondering 1) Is an iceberg the size of Delaware actually remarkable, or something that just happens from time-to-time? And 2) how they (actually) know the crack goes all the way to the ocean - can they actually see the water in images, or is this a hypothesis based on understanding of cracks of this length and width? I can ask as a separate questions if it's too much to ask here.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/H4Wmi.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/H4Wmi.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; Image from &lt;a href=&quot;http://www.livescience.com/57109-antarctic-ice-rift-is-70-miles-long.html&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;. &amp;quot;&lt;em&gt;A huge crack can be seen in the Antarctic Peninsula's Larsen C ice shelf in this aerial image snapped on Nov. 10, 2016, as part of NASA's IceBridge mission. Credit: NASA/John Sonntag&lt;/em&gt;&amp;quot;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;update:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;The rift continues to be tracked. If I understand correctly, it is now &lt;strong&gt;over 350 meters wide&lt;/strong&gt; and growing:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/U3vLI.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/U3vLI.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; From &lt;a href=&quot;http://www.projectmidas.org/blog/a-growing-rift-in-larsen-c/&quot; rel=&quot;noreferrer&quot;&gt;A growing rift on Larsen C&lt;/a&gt; at the &lt;a href=&quot;http://www.projectmidas.org/about/&quot; rel=&quot;noreferrer&quot;&gt;Project MIDAS&lt;/a&gt; website.&lt;/p&gt;&#xA;&lt;p&gt;More can be read about NASA's operation Ice Bridge program at its &lt;a href=&quot;https://www.nasa.gov/mission_pages/icebridge/index.html&quot; rel=&quot;noreferrer&quot;&gt;official website&lt;/a&gt;. These are a series of areal flights over antarctic regionss to collect images and data. The image above of the crack in the Larsen-C ice shelf was a featured photo and more can be read about it &lt;a href=&quot;https://www.nasa.gov/image-feature/rift-in-antarcticas-larsen-c-ice-shelf&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;. In the image gallery the caption states:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Rift in Antarctica's Larsen C Ice Shelf&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;On Nov. 10, 2016, scientists on NASA's IceBridge mission photographed an oblique view of a massive rift in the Antarctic Peninsula's Larsen C ice shelf. Icebridge, an airborne survey of polar ice, completed an eighth consecutive Antarctic deployment on Nov. 18.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The photo was also &lt;a href=&quot;https://twitter.com/NASA_ICE/status/797181527176122370&quot; rel=&quot;noreferrer&quot;&gt;featured in @NASA_ICE&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;A short video explaining the mission and showing details of the aircraft's science equipment can be seen below (and is &lt;a href=&quot;https://www.nasa.gov/feature/goddard/2016/nasa-nears-finish-line-of-annual-study-of-changing-antarctic-ice&quot; rel=&quot;noreferrer&quot;&gt;linked here&lt;/a&gt;):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=v3yMHHzLTCc&quot; rel=&quot;noreferrer&quot;&gt;https://www.youtube.com/watch?v=v3yMHHzLTCc&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-07-12T12:38:36.080" Title="Is this 70km crack in an ice shelf of Antarctica remarkable, or a regular occurrence?" Tags="|glaciology|antarctic|ice|sea-ice|ice-shelf|" AnswerCount="2" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="9263" PostTypeId="2" ParentId="9261" CreationDate="2016-12-07T07:52:38.117" Score="2" Body="&lt;p&gt;You are quite correct. At that latitude and elevation these can't be recent glacial features. Also, the lineations are too consistent to be glacial. In fact the features you note are Holocene and Pleistocene beach ridges. From Google Earth it appears that at least some of the ridges may be seif dunes, as there are also elongated barchan type dunes, which are often associated with seif dunes, and share the same axis, aligned with the prevailing wind. The inter-dune lakes also share the same consistent lineation. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-12-07T07:52:38.117" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9264" PostTypeId="1" AcceptedAnswerId="9275" CreationDate="2016-12-07T09:20:21.490" Score="3" ViewCount="650" Body="&lt;p&gt;I was wondering about how much unchecked deforestation would have to occur before we tipped the balance and started using more oxygen than was being replenished by plants and trees.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Last I heard it was estimated that every day an area the size of Wales was being removed globally which sounds like a very large amount. This could be inaccurate now as it was a long time ago. Many companies now plant trees to offset carbon footprint or whatever but assuming they didn't how long would we have?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question could be reduced to this - what area of land would need to be covered by forest to sustain life on earth without us all suffocating?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I imagine that this is a very simplistic view, it would probably cause global warming to accelerate first or the ecosystem to collapse and we'd all starve. I should say at this point that I am no scientist!&lt;/p&gt;&#xA;" OwnerUserId="7066" LastActivityDate="2019-08-28T14:43:18.350" Title="What rate of deforestation would be needed until we run out of oxygen?" Tags="|oxygen|deforestation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9266" PostTypeId="1" AcceptedAnswerId="9269" CreationDate="2016-12-07T23:14:47.610" Score="3" ViewCount="691" Body="&lt;p&gt;I see many scientific articles and newspapers out there saying that the climate change is happening.&#xA;Yet, there are people who believe climate change is a hoax and a lie. But I haven't seen any 'scientific' articles that support that climate change is a hoax.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are some reasons that some people believe that climate change is not real?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And is there any scientific articles (backed up by science) that support that climate change issue is not real? (A link to the website would be very helpful)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="7115" LastActivityDate="2016-12-09T09:24:05.700" Title="Climate change hoax" Tags="|climate|climate-change|temperature|earth-observation|" AnswerCount="2" CommentCount="11" ClosedDate="2016-12-09T14:35:52.040" ContentLicense="CC BY-SA 3.0" />
  <row Id="9267" PostTypeId="2" ParentId="9266" CreationDate="2016-12-08T04:53:32.737" Score="7" Body="&lt;p&gt;This stack exchange is about Earth &lt;strong&gt;&lt;em&gt;Science&lt;/em&gt;&lt;/strong&gt;. The scientific position is unequivocal in verifying the reality of climate change.  One is free to take a contrary skeptical position, but it isn't supported by climate data, ecological data, glaciology, atmospheric and oceanographic science, modelling, theoretical studies, feedback mechanisms, peer review scrutiny, or the basic premise of scientific method. 'Climate-change as a hoax', or 'global conspiracy' has nothing to do with science. It has everything to do with the psychology of denial, and the short-term expediency of vested big-business interests, notably in the oil and coal industries. So the reason you don't find genuine science articles refuting climate-change is that there aren't any such scientifically credible articles. This statement will of course prompt an avalanche of responses claiming that there is valid denialist science, which highlights the main problem of the internet - that most non-scientists cannot differentiate between junk science and real science. Consequently, they cannot differentiate between the media's beat-up 'controversy', and the exceptionally strong and consistent consensus of the scientific community. &#xA;My advice, writing as a climate change Earth-Scientist, is (1) don't take anyone's word unless it is from a professionally peer-reviewed paper, and (2) for starters, go to something like the World-Bank's climate-change knowledge portal, pick some locations at random, and check out the historic and projected temperature data. Both temperature and rainfall projections are given. I suggest that you concentrate on the temperature - the rainfall projections are less reliable. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Short answer - is there a credible anti-climate-change science site - No. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="543" LastEditDate="2016-12-08T14:33:02.473" LastActivityDate="2016-12-08T14:33:02.473" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9268" PostTypeId="1" CreationDate="2016-12-08T20:31:54.373" Score="2" ViewCount="349" Body="&lt;p&gt;Does the Earth position in the galaxy or solar system affect the orientation of the magnetic axis?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IOw8I.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IOw8I.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="6703" LastEditDate="2016-12-14T04:42:13.667" LastActivityDate="2016-12-14T04:42:13.667" Title="Why do the magnetic poles move?" Tags="|geomagnetism|solar-terrestrial-physics|poles|" AnswerCount="0" CommentCount="7" ClosedDate="2016-12-10T14:31:25.443" ContentLicense="CC BY-SA 3.0" />
  <row Id="9269" PostTypeId="2" ParentId="9266" CreationDate="2016-12-09T09:24:05.700" Score="0" Body="&lt;p&gt;As @farrenthorpe points out in a comment, the solar cycles are often pointed out as source of climate variability.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only peer-reviewed paper that I know of is the following:&#xA;&lt;a href=&quot;http://www.fel.duke.edu/~scafetta/pdf/scafetta-JSTP2.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Empirical evidence for a celestial origin of the climate oscillations&#xA;and its implications&lt;/a&gt; by &lt;a href=&quot;https://en.wikipedia.org/wiki/Nicola_Scafetta&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nicola Scafetta&lt;/a&gt; in the Journal of Atmospheric and Solar-Terrestrial Physics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nicola Scafetta has oten made the point that &quot;at least 60% of the global&#xA;warming observed since 1970 has been induced by the combined effect of the above natural climate&#xA;oscillations&quot; in the above paper, in several conferences and grey papers. See &lt;a href=&quot;http://scienceandpublicpolicy.org/images/stories/papers/originals/climate_change_cause.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; for example. But, as far as I know, no-one ever succeeded in reproducing its analysis...&lt;/p&gt;&#xA;" OwnerUserId="6001" LastActivityDate="2016-12-09T09:24:05.700" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9270" PostTypeId="2" ParentId="8927" CreationDate="2016-12-09T10:31:13.790" Score="3" Body="&lt;p&gt;After a lenghty unsuccessful search, I found an option to do my own mapping. There are &lt;a href=&quot;http://globalchange.bnu.edu.cn/research/soilw&quot; rel=&quot;nofollow noreferrer&quot;&gt;global datasets with the percentages of clay, silt and loam&lt;/a&gt; available from the Land-Atmosphere Interaction Research Group at Sun Yat-sen University and I used the &lt;a href=&quot;https://cran.r-project.org/web/packages/soiltexture/soiltexture.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;R soiltexture package&lt;/a&gt; for the classification. I ended up making a dataset covering my domain of interest in 2 km resolution. I attached my map and the original map mentioned in the question for comparison (some of the colours are a bit off, but they should more or less correspond to the same category in both images). If anyone is interested in this data, feel free to let me know. &lt;a href=&quot;https://i.stack.imgur.com/RhFAz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RhFAz.png&quot; alt=&quot;Custom mapping&quot;&gt;&lt;/a&gt;My custom mapping.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zZYRc.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zZYRc.png&quot; alt=&quot;Original dataset from the European Soil Data Centre (ESDAC)&quot;&gt;&lt;/a&gt;Original dataset from the European Soil Data Centre (ESDAC)&lt;/p&gt;&#xA;" OwnerUserId="6643" LastEditorUserId="6643" LastEditDate="2018-02-16T09:43:09.657" LastActivityDate="2018-02-16T09:43:09.657" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9271" PostTypeId="1" CreationDate="2016-12-09T11:13:29.693" Score="9" ViewCount="138" Body="&lt;p&gt;In particular, what happens if the Sawyer–Eliassen equation cannot be solved? I know that a condition for the Sawyer–Eliassen equation to have a solution is $F^2 N^2 - S^4 &amp;gt;0$, which means that the potential vorticity is positive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was wondering what is the physical implication of this condition on frontogenesis? Are there situations where fronts cannot be created, when potential vorticity is negative? Does that occur somewhere?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A secondary question would be the link with symmetric instability, which requires if I am not mistaken that the absolute vorticity (which is more or less potential vorticity) must be negative (in the northern hemisphere). I do not understand, then, how symmetric instability can arise when the Sawyer–Eliassen equation can be solved. Instability should occur in fronts since it is the driving phenomenon for the creation of precipitation bands!&lt;/p&gt;&#xA;" OwnerUserId="7120" LastEditorUserId="28050" LastEditDate="2018-03-05T16:34:18.053" LastActivityDate="2022-11-12T16:40:33.140" Title="In quasi-geostrophic frontogenesis, what happens if the potential vorticity is negative?" Tags="|meteorology|geophysics|synoptic|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9272" PostTypeId="1" AcceptedAnswerId="9276" CreationDate="2016-12-09T16:10:14.633" Score="4" ViewCount="472" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RJZW9.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RJZW9.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Lenght: 10 mm, striated, circular cross-section&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Site: Brno-Hády (limestone quarry), Moravia, Czech republic, central Europa&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Age: Jurassic, oxford&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The site is a good source of fossil shark teeth, but this tooth I am wondering about has absolutely different structure and does not have as strong luster as shark teeth have. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;An example of shark tooth fossil from Brno-Hády site:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/F2Zqh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/F2Zqh.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.flickr.com/photos/violetplanet/26006990296/in/album-72157665693696130/&quot; rel=&quot;nofollow noreferrer&quot;&gt;See my shark-tooth photos here&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="7031" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T16:36:25.627" LastActivityDate="2019-08-29T16:36:25.627" Title="I have found this fossil tooth, could it be pliosaur ? Or maybe theropod?" Tags="|fossils|paleontology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9275" PostTypeId="2" ParentId="9264" CreationDate="2016-12-09T23:40:10.767" Score="3" Body="&lt;p&gt;As Jan points out, there are many other factors in the oxygen balance, not just trees. But for a bit of fun, let us suppose that we burn all the trees on the planet. The global biomass of carbon is estimated as 47.4 PgC (it varies a bit according to season and inter-annual growth conditions). Of this we can estimate that the contribution from trees is about 36.3 PgC. 1 tonne of carbon consumes 2.67 tonnes of oxygen to create CO2, so the oxygen consumed is about 9.68 x 10^^10 tonnes. The total mass of the atmosphere is known to be 5.15 Petatonnes, of which oxygen is 20.95%, or 1.08 Petatonnes of oxygen. So taking the ratio, the loss of atmospheric oxygen from burning all the trees is 0.0034%. This is far less than the day-to-day fluctuations in available oxygen due to changes in atmospheric pressure - i.e. the weather. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, there is a lot of woody biomass, but think of the partial pressure of the oxygen layer that wraps the Earth: 21.2 kPa O2 on every square centimetre of the Earth's surface. We are never going to run out of oxygen! On the other hand, pyrolysis of every tree on the planet would create so much smoke that we would probably all die of lung cancer!&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-12-09T23:40:10.767" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9276" PostTypeId="2" ParentId="9272" CreationDate="2016-12-10T14:17:20.130" Score="6" Body="&lt;p&gt;Most likely plesiosaur. That fluted structure is indicative of marine reptile teeth. My first guess was mosasaur but their are a lot of plesiosaurs from that formation so I would go with that. It is obviously a shed tooth which makes it harder. shark teeth flare out at the base becasue they attach differently than marine reptile teeth, sharks need more surface area for a strong connection.  Hopefully a marine reptile person can give you a tighter identification, I mostly work on dinosaurs. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2016-12-10T14:23:06.373" LastActivityDate="2016-12-10T14:23:06.373" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9277" PostTypeId="2" ParentId="9021" CreationDate="2016-12-10T15:05:34.563" Score="0" Body="&lt;p&gt;One factor that helps you survive mass extinctions is small size becasue there are more of you and you can repopulate faster. Early birds are among the smallest dinosaurs. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other indicators of their relationship besides feathers which Kingledon covers are eggshells, dinosaurs and birds both have hard shelled eggs with identical microstructure. most dinosaurs have round spherical eggs but theropods have asymmetric elongate eggs just like birds. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The shape of the hand and forearm of early birds and maniraptoran dinosaurs are almost identical. both theropods and aves also have air-sac based breathing. Honestly in anatomy maniraptoran dinosaurs and early birds blur together so seamlessly there really is no compulsion other than a direct relationship.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;what throws most people off is the tail, but early birds have long tails (and teeth). we see a similar evolutionary path in pterosaurs, flying vertebrates start with long tails for passive stability but as they become better at flying shorten it to gain maneuverability and use better active control for stability. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was hoping to post this comparison of the skeletons of late maniraptorans and early birds done by Scott Hartman but the resolution sucks. Hopefully you can zoom in and see how seamlessly one blends into the other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0XdSk.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0XdSk.jpg&quot; alt=&quot;I was hoping to post this comparison of late maniraptorans and early birds but the resolution sucks.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2016-12-10T15:05:34.563" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9278" PostTypeId="1" CreationDate="2016-12-10T16:59:35.560" Score="2" ViewCount="109" Body="&lt;p&gt;I am confused how hematite can have a &quot;botryoidal&quot; habit when its crystal structure is trigonal, which is an angled structure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can an angled crystal present itself as rounded?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a botryoidal crystal of hematite is examined microscopically, is it clear that it is trigonal? How is that?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2016-12-10T22:14:45.150" Title="How can a crystal habit be round?" Tags="|mineralogy|crystallography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9279" PostTypeId="1" AcceptedAnswerId="9282" CreationDate="2016-12-10T18:30:46.807" Score="-2" ViewCount="1873" Body="&lt;p&gt;I have a basic question : Earth has 181 latitude lines, each having distance of 111 km. if i multiply that i will get 20091 KM, which could be the sum of distance from north pole to south pole i.e Diameter of earth, but the original diameter of earth is 12742 km, where does the 8000 Km value goes?&lt;/p&gt;&#xA;" OwnerUserId="7124" LastEditorUserId="87" LastEditDate="2016-12-25T22:50:01.930" LastActivityDate="2016-12-27T02:18:31.730" Title="Calculate the Diameter of earth using Latitude lines" Tags="|geography|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9280" PostTypeId="1" CreationDate="2016-12-10T19:07:30.000" Score="4" ViewCount="1226" Body="&lt;p&gt;During a family trip in the Israeli National Trail in the Pora Stream part (&lt;a href=&quot;https://goo.gl/maps/AvwfEahYm3k&quot; rel=&quot;noreferrer&quot;&gt;31.496871, 34.770928&lt;/a&gt;), I noticed these circular rock marks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any idea what are they?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5T2va.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5T2va.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/dObxl.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dObxl.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/xF0IL.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xF0IL.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/QlDd6.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QlDd6.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7125" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T09:16:17.547" LastActivityDate="2019-08-29T09:16:17.547" Title="Any idea what are these circular rock marks?" Tags="|geology|rocks|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="9281" PostTypeId="2" ParentId="9278" CreationDate="2016-12-10T20:13:10.740" Score="4" Body="&lt;p&gt;Botryoidal habit describes the arrangement of a large group of hematite crystals.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;While hematite's trigonal crystal system describes the geometry of a single unit crystal of hematite,  the two terms are really not related at all. Many minerals with different crystal systems can have a botryoidal habit. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The difference between a Botryoidal habit and mineral's unit crystal geometry is a difference in scale. A botryoidal habit can be measured in inches to feet while crystal geometry is measured in Ångstroms. &lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="6467" LastEditDate="2016-12-10T22:14:45.150" LastActivityDate="2016-12-10T22:14:45.150" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9282" PostTypeId="2" ParentId="9279" CreationDate="2016-12-11T02:32:18.647" Score="6" Body="&lt;p&gt;This question is more about surveying than earth science.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;OK. Assume the Earth is a perfect sphere. There are 360 degrees in a circle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One &lt;a href=&quot;https://en.wikipedia.org/wiki/Nautical_mile&quot; rel=&quot;noreferrer&quot;&gt;nautical mile&lt;/a&gt; is 1 minute of arc. There are 60 minutes in a degree and 21 600 minutes in a circle (60 x 360).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, one nautical mile is 1.852 km, therefore, the circumference of the Earth is 40 000 km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The circumference of a circle is given by ${\pi}d$, where $d$ is the diameter. Divide 40 000 km by $\pi$ &amp;amp; the diameter of the earth is 12 733 km&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2016-12-11T02:32:18.647" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9283" PostTypeId="2" ParentId="9261" CreationDate="2016-12-11T06:21:24.883" Score="5" Body="&lt;p&gt;That region forms part of the North Australian Craton and the underlying bedrock is in the order of 1.8 billion years old. The bedrock appears to be overlain by the Isa Superbasin during a period of deposition from 1.575 to 1.665 billion years ago and underwent the Ewamin Orogeny (1550 Ma) to form the Georgetown Inlier.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;About 500m years ago the Eastern seaboard of what is now Australia was under water and over the next 250m years continental subduction took place and Eastern Australia was geologically analogous to modern day Japan and China with an inland sea and a volcanic arc stretching from north to south. What was once this inland sea is now part of Australias rich coal basins, which stretch from Collinsville in Quensland all the way to Tasmania and they have also been correlated to coal deposits in Antarctica.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The region you question about, Starcke, is very close to what is known as the Tasman Line, which is a geological separation of the older 1.5 billion year old events and the younger 500 million year old events. The lines in the photo appear to be parallel to where the Tasman Line is shown to be. You'd really need to be on the ground checking out the geology to see how closely your photo images line up with the Tasman Line.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While all this was taking place, there was, amongst other events NE-SW compression of the continental crust along the Tasman Line which may have contributed to the geology in your picture. While I'd take a guess and say that many of those structures are folds (and they look like them too) I'd really need to put my boots on the ground and have a good look before I could say for sure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a link to an image of The Tasman Line.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://economicgeology.org/content/97/1/109/F1.large.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://economicgeology.org/content/97/1/109/F1.large.jpg&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A guy called Nick Direen wrote some good papers on the Tasman Line. You might find more info if you google him.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further to what I've written above, I've looked at the QLD government geological maps online at: &lt;a href=&quot;https://minesonlinemaps.business.qld.gov.au/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://minesonlinemaps.business.qld.gov.au/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As mentioned by Gordon, the surface geology is comprised of Quaternary age sand dunes which is indicated by the yellow colours. The purple areas are strata that is Devonian age and the small patches of pink are intrusive granites, which are typical of Eastern Australia. The sand dunes overlay the older rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How much the underlying bedrocks influence the sand dunes? Without further research and boots on the ground, I'd have difficulty in saying.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NrJfy.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NrJfy.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6463" LastEditorUserId="6463" LastEditDate="2016-12-11T22:05:22.890" LastActivityDate="2016-12-11T22:05:22.890" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9284" PostTypeId="1" CreationDate="2016-12-11T07:32:17.577" Score="3" ViewCount="333" Body="&lt;p&gt;I'm a junior studying math at a Canadian university and I'm planning on applying to oceanography grad schools. However, I haven't taken much physics or geology courses, and am just starting to swap out some of my math courses for courses like remote sensing and environmental modelling. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are some good grad schools for physical oceanography and what do they typically look for in an applicant? Will decent math and physics grades and high grades in geology courses look good, along with a decent GRE score? I'm thinking of applying to Canadian and US institutions. If you have any suggestions on where I can apply, I'd appreciate that too! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm interested in marine acoustics, ocean engineering, and physical oceanography in general. My top choices right now are Scripps, and the program at the University of New Hampshire.&lt;/p&gt;&#xA;" OwnerUserId="7127" LastEditorUserId="595" LastEditDate="2016-12-11T22:00:04.897" LastActivityDate="2016-12-11T22:00:04.897" Title="What do physical oceanography grad schools look for?" Tags="|ocean|oceanography|canada|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9285" PostTypeId="2" ParentId="9284" CreationDate="2016-12-11T08:28:51.737" Score="4" Body="&lt;p&gt;Most of the physical oceanography students I know studied mechanical engineering, physics or mathematics in undergrad. Strong physics and mathematical skills are very important. Programming is also a plus. Having a few earth sciences courses is good, but the physics and math is much more important, so I think you will be in good shape. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, beyond the basic background, clear ability to do research is very important in PhD admissions. Even if the applicant doesn't have any research experience, there are ways he/she can show that potential. A clear statement of purpose that outlines and contextualizes the problems the student wants to address in graduate school will catch the eye of any professor looking for students. There many students who have posters at AGU, GSA ect, however, the truth of the matter is that most undergraduates with research experience entering graduate school aren't ready to hit the ground running anyway. Professors know that, as they have had students before. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For courses, I would say skip the environmental modeling course unless it is directly related to what you want to research. Take the remote sensing, and instead of environmental modeling, take a full on numerical modeling course. A rigorous undergraduate level (or if you can stomach it, graduate level) will give you a very strong foundation for whatever simulations you may or may not to run during your career as scientist, even if you start out as a purely observational scientist. Fluid Mechanics is also a no brainer if you still have time. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, the oceanography researchers at LDEO (columbia university) are top notch. So are the ones at University of Washington, Hawaii, and Rhode Island. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Good luck on your applications, you have a lot of time to decide what you want to do (since your junior year just started I'm assuming). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The best advice I can give you is look at what researchers are doing on their websites and try and read a few of their papers. If you know any professors with these same interests, ask them what you don't understand.  Earth Sciences is much different than math (I came from pure physics), spend some time trying understand what an oceanographer does. If you can figure that out, you will be more than prepared to reflect that in your statement of purpose and you will be a stellar candidate for graduate school. &lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2016-12-11T08:28:51.737" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9286" PostTypeId="2" ParentId="9284" CreationDate="2016-12-11T21:58:49.533" Score="2" Body="&lt;p&gt;I agree that full-on numerical modelling is good but could be delayed to grad school, since the student has a strong math background. I think environmental modelling is important for an understanding of how conceptual models are constructed and then implemented mathematically. Yes to physics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other reason is so the person asking the question can find out if they are really interested in the discipline. It would be bad to get to grad school and then find out it isn't as good as it sounds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might look at Dalhousie University because of the proximity to Bedford Institute of Oceanography. Also check out the &lt;a href=&quot;http://jobs-emplois.gc.ca/fswep-pfete/index-eng.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Federal Student Work Experience Program&lt;/a&gt; and see if there is a chance to spend some time at BIO or elsewhere. That would look very good on an application.  &lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2016-12-11T21:58:49.533" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9288" PostTypeId="1" CreationDate="2016-12-12T10:57:37.290" Score="3" ViewCount="2083" Body="&lt;p&gt;It's obvious that in summer anticyclones bring hot weather. But why clear skies? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Heat evaporates the moisture and should lead to the cloud formation, shouldn't it?&lt;/p&gt;&#xA;" OwnerUserId="7006" LastEditorUserId="6093" LastEditDate="2016-12-12T21:18:12.770" LastActivityDate="2019-03-10T11:21:31.800" Title="Why do anticyclones bring clear skies in summertime?" Tags="|meteorology|atmosphere|temperature|humidity|evaporation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9289" PostTypeId="2" ParentId="8871" CreationDate="2016-12-12T17:53:52.073" Score="2" Body="&lt;p&gt;I don't know the exact percentage. But it is way more than just oil fields, EarthScope has done most of the continental US. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.usarray.org/researchers/obs/transportable&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.usarray.org/researchers/obs/transportable&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="32" LastActivityDate="2016-12-12T17:53:52.073" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9290" PostTypeId="2" ParentId="7283" CreationDate="2016-12-12T19:23:39.927" Score="22" Body="&lt;p&gt;It's hard to see the curvature of the earth from an altitude of 7 miles or 37,000 ft (typical cruising altitude of a jetliner) but easy to see from 250 miles (typical altitude of the ISS). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The line of sight from an aircraft at 37,000 feet = 235 miles. That's only about 3.4 degrees of the earth's surface. From the ISS at 250 miles, the line of sight is 1,435 miles, which covers about 19.8 degrees of the earth's surface - much easier to see the curve from this altitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Mxsv1.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Mxsv1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most people don't realize how large the earth is compared to the altitude of a passenger aircraft. It's easy to think we're really high up, but comparatively we're just skimming the surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The attached drawing is to scale, but the images of the jetliner and ISS are NOT to scale (much, much larger than their actual sizes).﻿&lt;/p&gt;&#xA;" OwnerDisplayName="user7130" LastActivityDate="2016-12-12T19:23:39.927" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9291" PostTypeId="2" ParentId="9288" CreationDate="2016-12-12T22:44:19.477" Score="8" Body="&lt;h2&gt;Why anticyclones are also called areas of high pressure&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Let's call anticyclones areas of high pressure. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Areas of high pressure (anticyclones), pull air towards the earth's surface. The increase in the number of air particles near the earth's surface causes a higher pressure for things on the earth, hence the name. &lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Impact of high pressure areas on weather&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;High-pressure areas &lt;strong&gt;don't&lt;/strong&gt; always bring hot weather. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;High pressure areas &lt;strong&gt;do&lt;/strong&gt; prevent the chances of clouds forming. Why? Because more air is pushing down around the earth's surface, rather than rising up in the air where it can cool and form clouds. &lt;strong&gt;This is why areas of high pressure (anti-cyclones) bring clear skies&lt;/strong&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because high-pressure areas prevent clouds forming, this can cause hot fine weather in summer when the temperatures are warm and sunny days are long, or cold weather in winter, when sunlight hours are short and the lack of clouds means any warm can escape from earth's surface and back out into space.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Background info on clouds and heat&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Heat generated by the sun travels two ways:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Towards Earth:&lt;/strong&gt; From the sun, through space, hitting the earth&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Away From Earth:&lt;/strong&gt; From the earth and back out into space&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Clouds reflect heat&lt;/strong&gt;. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Either &lt;strong&gt;away from earth&lt;/strong&gt;, as incoming sunlight hits the tops of&#xA;clouds, or            &lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;towards earth&lt;/strong&gt;, as heat radiating away from earth's surface towards space hits the bottom of a cloud and bounces back&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Areas of high pressure stop clouds from forming, which can mean warm summer days or cold winter days for the reason above! (In summer, a lot of sunlight can get through to the earth's surface, in winter when there's little sun, any of the earth's heat escapes into space with no cloud to stop it!) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I presume you are a beginner, so I've given a basic and easy to understand answer. Once you wrap your head around this, I can update with more details. &lt;/p&gt;&#xA;" OwnerUserId="5923" LastEditorUserId="5923" LastEditDate="2016-12-12T22:55:13.570" LastActivityDate="2016-12-12T22:55:13.570" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9292" PostTypeId="1" CreationDate="2016-12-12T23:53:49.503" Score="8" ViewCount="144" Body="&lt;p&gt;Methane has spiked sharply since 2014: BBC &lt;a href=&quot;http://www.bbc.com/news/science-environment-38285300&quot;&gt;Methane surge needs 'urgent attention'&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This coincides with a large increase in  fracking. So I'm wondering if there could be a connection? I don't think the target formations could release significant methane because they are generally so deep and pressurized. On the other hand, since the seismic footprint of fracking is so large compared to conventional drilling, could overlying shallow formations be sufficiently disturbed by explosions to release methane from near-surface sources?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="595" LastEditDate="2016-12-13T19:25:34.640" LastActivityDate="2016-12-14T02:40:38.443" Title="Methane from fracking?" Tags="|methane|fracking|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9294" PostTypeId="1" AcceptedAnswerId="9296" CreationDate="2016-12-13T14:22:58.130" Score="1" ViewCount="1225" Body="&lt;p&gt;I stumbled upon these terms in a text related to &lt;a href=&quot;https://en.wikipedia.org/wiki/Fish_farming&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pisciculture&lt;/a&gt; (fish farming).&lt;br /&gt;&#xA;I've looked on Google and Google-books but I couldn't find any type of definition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;P.S. Please let me know if I posted it in the right community.&lt;/p&gt;&#xA;" OwnerUserId="6215" LastEditorUserId="595" LastEditDate="2016-12-14T07:21:43.143" LastActivityDate="2016-12-14T07:24:44.763" Title="What are seasonal and perennial ponds?" Tags="|geography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9295" PostTypeId="1" CreationDate="2016-12-13T18:15:25.163" Score="-3" ViewCount="294" Body="&lt;p&gt;I do not know how to solve the shallow water equations in the matrix form in MATLAB. I didn't find anything useful on the internet. I have the specific mathematical equations to solve (please see the picture below) and I must write in MATLAB. If someone has examples, I would appreciate it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial u}{\partial t} - f\nu + g \frac{\partial \eta}{\partial x} = 0$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial \nu}{\partial t} + fu + g\frac{\partial \eta}{\partial y}=0$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial \nu}{\partial t}+H\big(\frac{\partial u}{\partial x} + \frac{\partial \nu}{\partial y}\big)=0$$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="7132" LastEditorUserId="6016" LastEditDate="2021-02-05T12:08:24.943" LastActivityDate="2021-02-05T12:08:24.943" Title="Where can I find a shallow-water solver in MATLAB?" Tags="|oceanography|models|homework|matlab|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="9296" PostTypeId="2" ParentId="9294" CreationDate="2016-12-14T00:15:52.860" Score="2" Body="&lt;p&gt;Seasonal ponds are ponds that only exist for part of the year. Jamesqf covered it well in his comment. There is just a wide variety of terms explaining the same thing. The terms were originally used more for streams (&lt;a href=&quot;https://en.wikipedia.org/wiki/Perennial_water&quot; rel=&quot;nofollow noreferrer&quot;&gt;Perennial water&lt;/a&gt;), but it has slid into broader usage. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="595" LastEditDate="2016-12-14T07:24:44.763" LastActivityDate="2016-12-14T07:24:44.763" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9297" PostTypeId="2" ParentId="9295" CreationDate="2016-12-14T02:17:48.330" Score="4" Body="&lt;p&gt;You aren't supposed to do link only answers, but that is really all this questions deserves. Did you look on Google? I did.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://people.sc.fsu.edu/~jburkardt/m_src/shallow_water_1d/shallow_water_1d.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://people.sc.fsu.edu/~jburkardt/m_src/shallow_water_1d/shallow_water_1d.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://personalpages.manchester.ac.uk/staff/paul.connolly/teaching/practicals/shallow_water_equations.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://personalpages.manchester.ac.uk/staff/paul.connolly/teaching/practicals/shallow_water_equations.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://sanders.eng.uci.edu/matlabcodes.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://sanders.eng.uci.edu/matlabcodes.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Those were 3 of the first 9 hits on google, and they all have code examples. There is no close option due to lack of effort, but I'll give it a downvote. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-12-14T02:17:48.330" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9298" PostTypeId="2" ParentId="9292" CreationDate="2016-12-14T02:40:38.443" Score="2" Body="&lt;p&gt;According to &lt;a href=&quot;http://www.eeb.cornell.edu/howarth/Howarth%20et%20al%20%202011.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Howarth, et al. 2011&lt;/a&gt;, from 4 wells they sampled, flow back after hydraulic fracturing lead to a release of methane equal to 0.6-3.2% of lifetime production of the well. Fracking wells released methane equal to 3.6-7.9% of lifetime production from all sources, while non-fracking wells released 1.7-6.2% of lifetime production.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2013JD021272/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;Petron, et al. 2014&lt;/a&gt; come to similar conclusions, though they don't provide data for lifetime individual well production to allow comparisons. They measured from an aircraft and found 10ppb to 100ppb increases in methane concentration in the air above wells at the Denver-Julenberg fracking site. They note that their estimated methane release is 2-3 times higher than the EPA's estimates (i.e. the estimates under which the fracking company filed its environmental impact statement). I don't like this study as much due to lack of information about what stage of production the wells are at (if they fracked two years ago and are still pumping, then this is just due to leaky pipes, not due to the fracking process).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In any case, there is some significant evidence that fracking is releasing more methane than it is expected to. The first paper adds some discussion of prevention measures and such. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will say this, it barely matters in the long run if the methane is leaking or being pumped into your furnace and burned. Methane isn't going to last too long in an oxygen atmosphere, and its all going to end up as CO$_2$ sooner or later. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-12-14T02:40:38.443" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9300" PostTypeId="1" CreationDate="2016-12-14T16:25:02.747" Score="5" ViewCount="130" Body="&lt;p&gt;I was assigned a task to prepare a report which states the current state of the art in Doppler wind LIDAR (DWL) visualization and visualization tools used in meteorology. In the last 3 days I've tried my best to find useful resources to prepare a report utilizing some known sites (e.g. google scholar, JURN, Scopus and few others), with not much success.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any research papers which explain 3D interactive visualization in Doppler WIND LIDAR or LIDAR technology?&lt;/p&gt;&#xA;" OwnerUserId="7140" LastEditorUserId="595" LastEditDate="2016-12-16T08:46:09.900" LastActivityDate="2016-12-16T08:46:09.900" Title="Software and methods used in LIDAR data visualization?" Tags="|meteorology|remote-sensing|software|visualization|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9301" PostTypeId="2" ParentId="8686" CreationDate="2016-12-14T20:09:20.040" Score="1" Body="&lt;p&gt;As @aretxabaleta points out in the comment above, chlorophyll concentrations are higher in polar regions as nutrient concentrations are higher due to the predominant low temperature conditions there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yoder et al (1993) also point out that algal, phytoplankton and other aquatic metaphyte productivity varies with latitudes and seasons (polar regions experience blooms in spring).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That being said, it is also important to know that chlorophyll concentrations vary with annual timescales as a result of temperature fluctuations so the average concentration is variable for that reason.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://m.earthobservatory.nasa.gov/GlobalMaps/view.php?d1=MY1DMM_CHLORA&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA earth observatory&lt;/a&gt; website has database of global chlorophyll concentration changes from 2002 to 2016. There's a colour coded animation that shows these changes on the site which I hope you will find helpful.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Reference:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yoder J.A., McClain C.R.  Feldman G.C. and Elias W.E. (1993). &quot;&lt;em&gt;Annual Cycles of Phytoplankton Chlorophyll&#xA; Concentrations in the Global Ocean a Satellite View&lt;/em&gt;&quot; American Geophysical Union.&lt;/p&gt;&#xA;" OwnerUserId="5273" LastActivityDate="2016-12-14T20:09:20.040" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9302" PostTypeId="1" AcceptedAnswerId="9305" CreationDate="2016-12-14T21:37:49.487" Score="7" ViewCount="1325" Body="&lt;p&gt;I keep hearing the term &quot;inversion layer&quot; when reading about pollution and meteorology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know it vaguely amounts to &quot;some place where the gradient of temperature is inverted&quot;.&#xA;But why are inversion layers so important in meteorology ? Why do they matter ? Air is colder here ... Big deal ! ?&lt;/p&gt;&#xA;" OwnerUserId="7144" LastActivityDate="2016-12-17T16:22:27.067" Title="Why are inversion layers so important in meteorology?" Tags="|meteorology|atmosphere-modelling|air-pollution|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9303" PostTypeId="2" ParentId="9302" CreationDate="2016-12-14T21:42:05.550" Score="5" Body="&lt;p&gt;Temperature inversions are important to meteorology and pollution because they are the boundary for atmospheric mixing.  If there is a strong inversion, the air above and below an inversion do not easily mix together.  In the case of pollution, where the emissions come from the surface, a shallow temperature inversion in the boundary layer traps the pollution near the surface.  If the boundary layer inversion is very high up in the atmosphere, you will get good mixing and pollution will be diluted.  There is also a very strong temperature inversion at the top of the troposphere, called the tropopause, which generally separates stratospheric air from the troposphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, see this related question: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/5123/what-is-a-temperature-inversion-and-can-it-trap-smog-pollution?rq=1&quot;&gt;What is a temperature inversion and can it trap smog pollution?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2016-12-17T16:22:27.067" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9304" PostTypeId="2" ParentId="9302" CreationDate="2016-12-15T00:27:11.613" Score="6" Body="&lt;p&gt;Farrenthope is correct, but I would like to add some detail.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An inversion occurs when the air is warmer than the ground. It is called an inversion because it is the opposite of what occurs during the day. During the day, the ground is heated by the sun and the air near the ground rises.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, during clear and calm nights, the ground will cool faster than the air. This means that at a certain time, the air will be warmer than the ground. With nothing to move pollutants upward, the air just stagnates. People will still keep pumping pollutants out, with the pollution just accumulating. During the day, however, the pollutants are lifted upwards, and do not stagnate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For those mathematically affluent, the equation for a concentration of a pollutant can be written as $$\frac{\partial c}{\partial t}=-\vec{v}\cdot\nabla_h c-w\frac{\partial c}{\partial z}+\nabla \cdot (K\nabla c) +S_c(t)+C$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $c$ is the concentration of the pollutant, $\vec{v}$ is the wind vector, $w$ is the vertical velocity, $K$ is the Fick's law constant, and $C$ is the chemistry term.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we consider the following assumptions which are common, regardless of an inversion:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Diffusion is a small process ($K\approx0$)&lt;/li&gt;&#xA;&lt;li&gt;The pollutant undergoes no chemical change ($C\approx0$)&#xA;The equation boils down to&#xA;$$\frac{\partial c}{\partial t}=-\vec{v}\cdot\nabla_h c-w\frac{\partial c}{\partial z}+S_c(t)$$&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;During an inversion, because air at the surface is not going up, there is no air going down. This means $w\approx0$. With no vertical velocity, the air near the ground is slowed by the drag the ground has on the air, making $\vec{v}\approx0$. This boils the equation down to $$\frac{\partial c}{\partial t}=S_c$$.&#xA;Since $S_c \ge0$, $c$ will just keep increasing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good example of a dangerous inversion is the &lt;a href=&quot;https://en.wikipedia.org/wiki/1948_Donora_smog&quot; rel=&quot;noreferrer&quot;&gt;Donora event&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2016-12-15T00:27:11.613" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9305" PostTypeId="2" ParentId="9302" CreationDate="2016-12-16T04:16:09.630" Score="3" Body="&lt;p&gt;Put it this way:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We like our air to be mixed around well.  Mixing the air prevents uneven concentration buildup of not just pollutants (smoke, ozone, chemicals, etc), but also fog (which is pooling of cool and moist air), smells, even &lt;a href=&quot;http://mocpa.com/inversion.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;sounds&lt;/a&gt; (that's why you can often hear distant traffic more near dawn).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two places that air near the ground can go: up or out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Warmer air rises.  When an inversion sets up, it's a layer of warmer air aloft that thereby blocks air below from being able to rise anymore.&lt;br&gt;&#xA;Most nights there are inversions since the ground cools more quickly than the air higher up.  But usually during the day, sunlight heating the ground starts the air rising and mixing around.  And viola, no more unpleasant buildups!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But additionally, inversions also are formed when cold air is blown in near ground level, such as during a cold front.  But, the peak of such a cold airmass generally associates with high pressure.&lt;br&gt;&#xA;And high pressure cores have calmer horizontal winds.&lt;br&gt;&#xA;So when such a cold high pressure gets stuck and parks in place, it can lead to prolonged inversions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, inversions tend to be self-perpetuating over time.  Fog and smoke form, block out the sun, and those just keep the low-level air layer cold.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It can be very difficult to forecast just how much the inversion will break down during the day, leading to greatly busted forecasts.  I remember many times in Oklahoma where they thought it would warm up a fairly typical 20 degrees (F) during the day, but the fog never fully eroded, and we only ended up rising a few degrees.&#xA;We also ended up having solid weeks or more of foggy conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, the geography in some regions favors inversion formation, and so inversion forecasting inversions can be particularly important for such locations.  Sometimes these features can even &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/2009MWR2819.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;enhance storm systems or alter their tracks&lt;/a&gt;.  For more on these targets, look into &lt;a href=&quot;https://en.wikipedia.org/wiki/Cold-air_damming&quot; rel=&quot;nofollow noreferrer&quot;&gt;cold air damming&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Marine_layer&quot; rel=&quot;nofollow noreferrer&quot;&gt;marine layers&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Inversion conditions also can prove to be quite important flies-in-the-ointment for severe storm forecasting as well.  Severe thunderstorms often rely quite a lot on afternoon heating to fuel the rapid updrafts of the storms.  Sometimes the same mugginess that highlights that conditions are ripe for storms can wind up being so rich that fog and low-level clouds develop overnight, and prove resilient well into the day.  The result can be that the forecast severe weather outbreaks ends up coming to nothing.  Or instead, if a fog inversion were expected but doesn't materialize it can often generate unexpected or incorrectly timed severe weather outbreaks.  So severe weather forecasters have significant interest in understanding inversions as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So... inversions form most every day, but typically as the day evolves, the atmospheric heating engine kicks in, and wind resets the atmosphere towards being more homogeneous.  But when stronger inversions build in, they can snowball into much more depressing, and even very &lt;a href=&quot;http://www.history.com/news/the-killer-fog-that-blanketed-london-60-years-ago&quot; rel=&quot;nofollow noreferrer&quot;&gt;dangerous&lt;/a&gt; conditions.  &lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2016-12-16T09:48:13.980" LastActivityDate="2016-12-16T09:48:13.980" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9306" PostTypeId="1" CreationDate="2016-12-16T04:29:51.140" Score="10" ViewCount="13129" Body="&lt;p&gt;I've heard that it's colder after a storm. I think this is an interesting question, not least because of the implicit comparison: &lt;em&gt;colder than what?&lt;/em&gt; A few different comparisons come to mind, and still others may occur to you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have in mind that &lt;em&gt;after a storm&lt;/em&gt; means &lt;em&gt;the day after&lt;/em&gt; the storm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd love to hear responses to any or all of these. Is it colder after a storm relative to:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;how it was right before the storm?&lt;/li&gt;&#xA;&lt;li&gt;how it is the day after the day after the storm?&lt;/li&gt;&#xA;&lt;li&gt;how it would've been without the storm?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I'm interested in statistical answers as well as theory-based answers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;@JeopardyTempest rightly points out that I haven't specified what I mean by &lt;em&gt;storm&lt;/em&gt;. I'm not too picky here, I'm thinking of events that are between hours and days.&lt;/p&gt;&#xA;" OwnerUserId="6708" LastEditorUserId="6708" LastEditDate="2018-05-02T23:11:56.463" LastActivityDate="2018-05-02T23:11:56.463" Title="Is it typically colder after a storm?" Tags="|meteorology|weather-forecasting|storms|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="9307" PostTypeId="2" ParentId="9306" CreationDate="2016-12-16T09:35:46.690" Score="14" Body="&lt;p&gt;The major factors in temperature change from precipitation...&#xA;&lt;hr&gt;&#xA;&lt;strong&gt;First&lt;/strong&gt;, fundamentally rain is falling to the ground from higher in the sky.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Precipitation typically comes from a location where it is colder compared to us on the ground (the troposphere generally is cooler with height, on average around 6.5 Celsius\km.).&lt;br&gt;&#xA;Basically, the rain itself usually at least feels colder than the air beforehand, right??&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Well, if you do bring something colder to a warmer environment, their temperatures will tend to move towards a balance between the two.&lt;br&gt;&#xA;[++ see &lt;a href=&quot;https://www.grc.nasa.gov/www/k-12/airplane/thermo2.html&quot; rel=&quot;noreferrer&quot;&gt;Second Law of Thermodynamics&lt;/a&gt; ++]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So with significant rainfalls, there's a lot of cold water being spread down into our warmer air, and due the dispersed nature of rain (a bunch of small drops rather than one giant stream) it ensures that rain is quite quick and effective in spreading it's cold temperatures into the air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;hr&gt;&#xA;&lt;strong&gt;Second&lt;/strong&gt;, falling rain also encourages downward air movement, due to friction.&lt;br&gt;&#xA;[++ see &lt;a href=&quot;http://www.boldmethod.com/learn-to-fly/weather/microbursts-and-how-they-affect-your-plane/&quot; rel=&quot;noreferrer&quot;&gt;downdrafts&lt;/a&gt; ++]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So not only is rain (that is almost always colder) coming down, but air (that is almost always colder) is coming down too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, rain is cooling the air it is falling through, colder air sinks, so the downdraft is further enhanced.&lt;br&gt;&#xA;[++ Actually the air must be quite a bit cooler to sink on its own... see &lt;a href=&quot;http://www.kidsgeo.com/geography-for-kids/0070-adiabatic-temperature-changes.php&quot; rel=&quot;noreferrer&quot;&gt;adiabatic warming&lt;/a&gt; ++]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So this is a second fairly quick cooling process, as downdrafts occur within the lifecycle of a thunderstorm cell/complex.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;And &lt;strong&gt;third&lt;/strong&gt;, some of the rain/snow/sleet/hail/etc water will begin to evaporate (or &lt;a href=&quot;https://en.wikipedia.org/wiki/Sublimation_(phase_transition)&quot; rel=&quot;noreferrer&quot;&gt;sublimate&lt;/a&gt;!) as it is falling and once it reaches the ground, unless the air is totally saturated.  When water evaporates, it needs to gain energy.  To do so, it takes energy from the environment, namely the air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This evaporative cooling just exacerbates the first two influences above.  And furthermore can continue to have impacts days after the rainfall compared to drier places, stunting high temperature ascension during the afternoon.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;[There are also other factors important in the longer term, such as snow reflecting sunlight (cooling the area), moister air being favored for cloud formation (which cools during the day, warms at night), and the fact moister air changes temperature at a slower rate due to its &lt;a href=&quot;https://www.e-education.psu.edu/earth103/node/1005&quot; rel=&quot;noreferrer&quot;&gt;heat capacity&lt;/a&gt; (cooling during the day, warming at night).]&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;But, the result is, &lt;strong&gt;scientifically, when precipitation falls, it is fundamentally a cooling process&lt;/strong&gt;.&lt;br&gt;&#xA;The stronger the precipitation is, the much more significant the cooling.  And certain atmospheric setups enhance the cooling effect even more (steep &lt;a href=&quot;https://en.wikipedia.org/wiki/Lapse_rate&quot; rel=&quot;noreferrer&quot;&gt;lapse rates&lt;/a&gt;, dry air nearer the ground)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, even after saying all that, it actually &lt;strong&gt;can still be warmer soon after rainfall&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How in the world is that possible!?!&lt;br&gt;&#xA;&lt;strong&gt;Because wind can still blow in large amounts of air from other areas... sometimes from environments that haven't yet themselves experienced significant precipitation.&lt;/strong&gt;&lt;br&gt;&#xA;This often happens as &lt;a href=&quot;https://www.youtube.com/watch?v=tsD6zkBMmck&quot; rel=&quot;noreferrer&quot;&gt;warm fronts&lt;/a&gt; pass.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;[++ Heaviest rainfalls do more often come with cold fronts, which bring in more cold air.  However most (nontropical) lows start with a balance of areas of advancing warm air followed by surging cold air.  So you may well see both... or you may not: in more mature storm systems - as you'll often see in winter - most warm air is completely undercut by cold air... and so many large areas never experience any notable warmup as a storm system works through ++]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other unbalanced factors can overwhelm the cooling effect as well... like when it's cloud all day, then rains a bit, but finally the sun comes out.  The hot sun can quickly turn the battle back towards the warmer side.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[++ There is indeed at least one other very very rare way, where if the atmosphere is setup perfectly, a strong downdraft can actually begin to warm due to adiabatic compression, but still have enough oomph to reach the ground... and you wind up with a &lt;a href=&quot;http://www.weatherimagery.com/blog/what-is-a-heat-burst/&quot; rel=&quot;noreferrer&quot;&gt;heat burst&lt;/a&gt;. ++]&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;So air after rainfall is cooled in the extreme majority of cases... it's just that your cooled air may instead end up being relocated to other locations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Check out the topic of &lt;a href=&quot;https://www.e-education.psu.edu/meteo361/l6_p6.html&quot; rel=&quot;noreferrer&quot;&gt;outflow boundaries&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, to your questions:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;⇒ Will it be colder right after a storm compared to how it was&#xA;   right before the storm?&lt;br&gt;&#xA;   &lt;strong&gt;Most likely&lt;/strong&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;⇒ Will it be colder the day after a storm compared to how it was right before the storm?&lt;br&gt;&#xA;   &lt;strong&gt;Depends what the weather pattern and air mass movement is like.  If a cold front moves in, yes.  If a warm front moves in, no.  In the tropics or during the height of summer, it will often be about the same the next day as the atmosphere mixes the cool air from yesterday's rain around until it's spread out and minimized, and the air heats back up again the next day when the sun comes out.&lt;/strong&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;⇒ Will it be colder after a storm than it otherwise would have been without the storm?&lt;br&gt;&#xA;  &lt;strong&gt;Basically yes.  A nearby site that doesn't get the storm's effects will almost certainly be warmer.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-05-01T16:56:04.913" LastActivityDate="2018-05-01T16:56:04.913" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9309" PostTypeId="2" ParentId="9232" CreationDate="2016-12-16T19:11:37.723" Score="3" Body="&lt;p&gt;&lt;a href=&quot;http://dx.doi.org/10.1006/jasc.1999.0431&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nur &amp;amp; Cline (2000)&lt;/a&gt; constructed a &lt;a href=&quot;https://berlinarchaeology.files.wordpress.com/2012/09/nur-and-cline-2000.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;map of sites&lt;/a&gt; destroyed in the Aegean and Eastern Mediterranean region during the years 1225–1175 BCE. They also provided a map of earthquakes of magnitude above 6.5 that were measured during the XX century. They claimed that &quot;virtually all of these Late Bronze Age sites lie within the affected (“high-shaking”) areas&quot;. They also showed evidence of earthquake damage in many of the main cities of the area and point out that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;While such a ‘‘storm’’ is unlikely to have been the sole cause&#xA;  of the end of the Late Bronze Age in the Aegean and the Eastern Mediterranean, it may have interacted with the other forces at work in these areas c. 1200 BCE&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The idea of an &quot;earthquake storm&quot; has been around at least since 1970. &lt;a href=&quot;http://dx.doi.org/10.1016/0040-1951(70)90014-4&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ambraseys (1970)&lt;/a&gt; describe multiple &quot;earthquake sequences&quot; lasting around 40-50 years with &quot;quiet periods of more than a century in a nearby fault system (the Anatolian fault zone).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a study preceding the Nur &amp;amp; Cline work, &lt;a href=&quot;http://adsabs.harvard.edu/full/1998ncdb.conf..140N&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nur (1998)&lt;/a&gt; provided a possible explanation to connect earthquake damage with civilization collapse:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The earthquake in this ca. 50 year long storm could have render many of the urban centers militarily vulnerable, thus inviting attacks not by powerful, distant Sea People, but by opportunistic indigenous or neighboring populations. These attack might have led in turn to the political and social collapse of the centres, followed by a dark age of recovery and rebuilding often lasting a few hundred years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They also provide an example from the Old Testament: Jericho, that was attack by invaders after the city walls collapse. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A simple explanation of the potential set of events is given in &lt;a href=&quot;https://www.youtube.com/watch?v=ErOitC7OyHk&quot; rel=&quot;nofollow noreferrer&quot;&gt;this video&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2016-12-16T19:11:37.723" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9310" PostTypeId="2" ParentId="331" CreationDate="2016-12-16T23:14:33.913" Score="1" Body="&lt;p&gt;It would appear that you are spot on with the commonly used terms in your question.  A well-referenced post on the Arctic forums (not by me) entitled '&lt;a href=&quot;https://forum.arctic-sea-ice.net/index.php?topic=1005.0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Average sea ice thickness vs effective sea ice thickness&lt;/a&gt;', provide information about this very question.  Specifically:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Average Sea Ice Thickness = Volume of Sea Ice/Ice Covered Area&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Effective Sea Ice Thickness = Volume of Sea Ice/Grid Cell Area&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the author of the post, (an Administrator of that site), these terms are imbedded in a lot of the published literature - for example, in the article &quot;&lt;a href=&quot;http://www.the-cryosphere.net/8/705/2014/tc-8-705-2014.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Uncertainties in Arctic sea ice thickness and volume: new estimates and implications for trends&lt;/a&gt;&quot;.&lt;/p&gt;&#xA;" OwnerDisplayName="user7154" LastActivityDate="2016-12-16T23:14:33.913" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9311" PostTypeId="1" AcceptedAnswerId="9312" CreationDate="2016-12-17T12:10:48.963" Score="-3" ViewCount="210" Body="&lt;p&gt;Except diamondת which mineral is having high hardness in Mohr scale.  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A Oxide&lt;/li&gt;&#xA;&lt;li&gt;B silicate&lt;/li&gt;&#xA;&lt;li&gt;C carbonate&lt;/li&gt;&#xA;&lt;li&gt;D phosphate&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="7157" LastEditorUserId="725" LastEditDate="2016-12-18T07:37:52.707" LastActivityDate="2016-12-18T07:37:52.707" Title="To find hardness in Mohrs scale" Tags="|geology|mineralogy|homework|crystallography|" AnswerCount="1" CommentCount="4" ClosedDate="2016-12-19T12:51:07.620" ContentLicense="CC BY-SA 3.0" />
  <row Id="9312" PostTypeId="2" ParentId="9311" CreationDate="2016-12-18T07:37:05.453" Score="4" Body="&lt;p&gt;Although this is a somewhat poorly researched question, I think there is an opportunity to make a nice point here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First of all, let's look at the Mohs scale:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Talc&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Gypsum&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Calcite&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Fluorite&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;(fluor)Apatite&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;K-Feldspar&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Quartz&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Topaz&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Corundum&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Diamond&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Their (&lt;em&gt;simplified&lt;/em&gt;) chemical formulae are:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{Mg3Si4O10(OH)2}$&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{CaSO4\cdot2H2O}$&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{CaCO3}$&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{CaF2}$&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{Ca5(PO4)3F}$&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{KAlSi3O8}$&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{SiO2}$&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{Al2SiO4F2}$&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{Al2O3}$&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{C}$&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;What are the anionic groups in each mineral? These are the anions that the metallic cations bond to in the mineral. Let's see:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{Si4O10(OH)2}$ : hydrous silicate&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{SO4}$ : sulfate&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{CO3}$ : carbonate&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{F2}$ : halide (fluoride)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{(PO4)3F}$ : phosphate-fluoride&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{Si3O8}$ : silicate&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{SiO2}$ : silicate (although can be regarded as oxide, but it has the silicate framework)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{SiO4F2}$ : silicate-fluoride&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{O3}$ : oxide&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;$\ce{C}$ : covalently bonded carbon, no anions here&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;This should help you find the correct answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this is only relevant for the Mohs scale. This does not mean, for example, that all oxides are harder than all silicats. Magnesium oxide is pretty soft, for example.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-12-18T07:37:05.453" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9313" PostTypeId="5" CreationDate="2016-12-18T10:56:14.993" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2016-12-18T10:56:14.993" LastActivityDate="2016-12-18T10:56:14.993" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9314" PostTypeId="4" CreationDate="2016-12-18T10:56:14.993" Score="0" Body="Hydraulic fracturing (also fracking, fraccing, hydrofracturing or hydrofracking) is a well stimulation technique in which rock is fractured by a pressurized liquid." OwnerUserId="477" LastEditorUserId="477" LastEditDate="2016-12-18T21:09:05.813" LastActivityDate="2016-12-18T21:09:05.813" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9315" PostTypeId="2" ParentId="7425" CreationDate="2016-12-19T15:45:00.000" Score="1" Body="&lt;p&gt;Yes &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is one of most common compounds in the universe. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Methane#Extraterrestrial_methane&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Methane#Extraterrestrial_methane&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which period of the early earth do you want to know about? the earliest atmosphere likely had less methane than now. &lt;a href=&quot;http://science.sciencemag.org/content/308/5724/1014&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://science.sciencemag.org/content/308/5724/1014&lt;/a&gt;&#xA;But once life evolved methane rose.&#xA;&lt;a href=&quot;http://www.minersoc.org/pages/Archive-MM/Volume_62A/62a-2-751.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.minersoc.org/pages/Archive-MM/Volume_62A/62a-2-751.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2016-12-19T15:45:00.000" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9316" PostTypeId="1" CreationDate="2016-12-19T17:00:00.350" Score="8" ViewCount="3096" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Red_rain_in_Kerala&quot; rel=&quot;noreferrer&quot;&gt;red rain&lt;/a&gt; phenomenon in Kerala, India has been reported several times in history (1896, 2001, 2012). The color of the rain seems to be associated with the presence of airborne spores of the algae &lt;em&gt;Trentepohlia annulata&lt;/em&gt;. My questions are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;What concentrations of spores are necessary for the rain to achieve this color?&lt;/li&gt;&#xA;&lt;li&gt;What physical and biological mechanisms are involved to achieve those concentrations in suspension?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/25IQV.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/25IQV.jpg&quot; alt=&quot;The &amp;quot;red rain&amp;quot; incident once happened in Kerala, India. Now, it happened in the Bangladesh. It was the after result of the red rain. Mistri para, Khulna, Bangladesh.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2020-12-26T13:01:16.213" Title="Causes and concentration of red rain of Kerala" Tags="|precipitation|rainfall|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9317" PostTypeId="1" AcceptedAnswerId="9320" CreationDate="2016-12-19T19:50:58.653" Score="1" ViewCount="1488" Body="&lt;p&gt;I often come across the words &quot;atmospheric forcing&quot; or &quot;meteorological forcing&quot; in journals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I presume it just means the influence/impacts of the atmosphere upon factors such as climate, wind patterns and tidal/ocean currents. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this is a presumption. Am I correct? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;An example is located on page 11 of this &lt;a href=&quot;http://www.ub.uib.no/elpub/2003/h/406002/hovedoppgave.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5923" LastEditorUserId="5923" LastEditDate="2016-12-20T11:55:26.803" LastActivityDate="2016-12-20T16:31:39.090" Title="Does &quot;atmospheric forcing&quot; have a stated definition?" Tags="|meteorology|atmosphere|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9320" PostTypeId="2" ParentId="9317" CreationDate="2016-12-20T16:31:39.090" Score="3" Body="&lt;p&gt;The example that you've linked to (Larsen, 2003, &quot;An investigation of the Faroe Shelf Front&quot;, Univ. of Bergen) is a description of various processes that contribute to the existence and variability of an ocean front around the Faroe Isles.  As an oceanography thesis, it's mainly concerned with the ocean state (e.g., temperature, salinity) and local, internal process that affect the front.  But the introduction also mentions external process that affect the local ocean state, such as the wider-scale ocean state/fluxes, topography and &lt;em&gt;atmospheric forcing&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could loosely think of these three respectively as the lateral, lower and upper boundary conditions for the local block of ocean of interest around the Faroes. In this context it could also be phrased as the &lt;em&gt;forcing of the ocean by the atmosphere&lt;/em&gt;, so how the ocean is affected by the exchange with the atmosphere of quantities such as heat, water and momentum.  Larsen summarizes these through descriptions of air temperature and heat flux, precipitation, evaporation and runoff, and wind speed and direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Often when we're interested in a particular physical realm (e.g., atmosphere, ocean, land or ice-sheets) we prescribe (i.e., force) the interactions it has with the other realms to make it easier to investigate processes &lt;em&gt;within&lt;/em&gt; the realm.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2016-12-20T16:31:39.090" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9321" PostTypeId="1" AcceptedAnswerId="9325" CreationDate="2016-12-20T18:49:40.860" Score="3" ViewCount="1234" Body="&lt;p&gt;In the diagram below, well A is an artesian well and well B is a normal well.&#xA;Well B's pipe is lower than the water table. By looking at the picture, I decide that well A would try quicker than well B, but the answer said that well B would try quicker than well A. I researched on the Internet, but all I found was how to improve your well.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/47i6R.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/47i6R.jpg&quot; alt=&quot;Well diagram&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why does an artesian well dry slower than a normal well?&lt;/p&gt;&#xA;" OwnerUserId="6784" LastActivityDate="2016-12-21T11:22:33.060" Title="Why does an artesian well dry slower than a normal well?" Tags="|water|groundwater|water-table|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9322" PostTypeId="1" AcceptedAnswerId="9328" CreationDate="2016-12-20T19:21:05.513" Score="8" ViewCount="239" Body="&lt;p&gt;What typical fraction of decomposing plant matter, left on the surface rather than buried, is not released in gaseous form?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My simple world view is that the plant structure has all come from the air, water content in the ground and a few nutrients and so I am wondering if the process of decomposition leaves just a tiny percentage of nutrients or if some larger fraction is left as solid material.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I had thought of posting this on &lt;em&gt;sustainability.stackexchange&lt;/em&gt; though I am looking for a rational explanation rather than a practical experience.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lastly, I appreciate the answer is likely to vary according to type of plant matter. If it helps I'm thinking of the UK, and a mixture of deciduous (beech, hazel, and oak), yew, spruce, and other grasses and shrubs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clearly I understand that the timescales applicable to woody stems and branches will be much longer than for green shoots and leaves.&lt;/p&gt;&#xA;" OwnerUserId="5375" LastEditorUserId="6784" LastEditDate="2016-12-20T20:33:42.263" LastActivityDate="2016-12-21T20:13:36.380" Title="What is the residue after plant matter is completely decomposed?" Tags="|atmosphere|soil|co2|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9323" PostTypeId="1" CreationDate="2016-12-20T23:10:33.950" Score="3" ViewCount="175" Body="&lt;p&gt;On the east coast of Australia, the predominant summer thunderstorm pattern seems to be the derecho variety that develops ~300-400 km inland in late morning / early afternoon, and reaches the coast by late afternoon / early evening as a squall line 100-200 km long.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oftentimes this pattern will repeat itself over several days. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In these cases, is each day's derecho event triggered by a new moving cold front, or is the multi-day phenomenon due to a single stationary cold front which remains in place throughout the several day period, or are both scenarios possible?&lt;/p&gt;&#xA;" OwnerUserId="7027" LastActivityDate="2016-12-20T23:10:33.950" Title="Are thunderstorms on consecutive days due to distinct cold fronts" Tags="|severe-weather|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9324" PostTypeId="1" AcceptedAnswerId="9326" CreationDate="2016-12-21T09:11:27.457" Score="8" ViewCount="246" Body="&lt;p&gt;I saw &lt;a href=&quot;https://www.google.com/maps/@30.378725,9.050503,7822m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;this landform on Google Earth&lt;/a&gt; on the border of Algeria/Tunisia/Libya and wondered what it is called (so that I can read up on it and find out how it forms - I am not a geologist):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eefYl.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eefYl.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.com/maps/@30.4018266,8.7950013,3316a,20y,82.69h,82.08t/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here is a 3D view&lt;/a&gt;: (Press Ctrl + drag left mouse button to rotate)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FD6gv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FD6gv.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone know what kind of landform this is?&lt;/p&gt;&#xA;" OwnerUserId="7175" LastEditorUserId="595" LastEditDate="2016-12-21T09:45:25.020" LastActivityDate="2016-12-22T09:38:46.817" Title="Identifying a desert landform" Tags="|geography|geomorphology|desert|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9325" PostTypeId="2" ParentId="9321" CreationDate="2016-12-21T11:22:33.060" Score="8" Body="&lt;p&gt;Well B is a normal water table well, which will have a relatively steep, tight, local, and deep 'cone of depression'. Well A doesn't have a 'cone of depression' - it has a 'cone of depressurization', which has an entirely different physical configuration. That is, wide and shallow. So the drawdown in well B will fall rapidly, whilst there isn't really a drawdown in well A, at all. Rather, the &lt;em&gt;pressure surface&lt;/em&gt; in well A decreases until much of the aquifer - typically several square kilometres - is depressurized. Note that the two processes are entirely different. In a water table aquifer pumping actually drains the pores between grains in the upper aquifer, like water draining out of a sponge. In a confined aquifer, the yield is supplied by depressurizing the aquifer - so the saturated surface doesn't actually drain at all.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-12-21T11:22:33.060" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9326" PostTypeId="2" ParentId="9324" CreationDate="2016-12-21T14:35:24.547" Score="9" Body="&lt;p&gt;Star dunes, caused by the prevailing winds coming from multiple directions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take a look at these different &lt;a href=&quot;https://www.nps.gov/grsa/learn/nature/dune-types.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;dune types&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="6093" LastEditDate="2016-12-22T09:38:46.817" LastActivityDate="2016-12-22T09:38:46.817" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9327" PostTypeId="1" CreationDate="2016-12-21T14:35:53.363" Score="1" ViewCount="85" Body="&lt;p&gt;There is Greenwich Mean Time (GMT) and British Summer Time (BST). One is used in the United Kingdom (UK) in the winter, and the other in summer. Is there a three letter abbreviation for the time zone which means current UK time regardless of time of the year?&lt;/p&gt;&#xA;" OwnerUserId="7176" LastEditorUserId="477" LastEditDate="2016-12-24T16:30:14.057" LastActivityDate="2016-12-24T16:30:14.057" Title="What is this time zone called?" Tags="|earth-rotation|time|" AnswerCount="0" CommentCount="6" ClosedDate="2016-12-21T20:44:47.307" ContentLicense="CC BY-SA 3.0" />
  <row Id="9328" PostTypeId="2" ParentId="9322" CreationDate="2016-12-21T16:21:48.917" Score="6" Body="&lt;p&gt;From &lt;a href=&quot;http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.474.7358&amp;amp;rep=rep1&amp;amp;type=pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mary, et al., 1996&lt;/a&gt;, Figure 1 on the second page shows a nice breakdown of there the Carbon and Nitrogen go when a plant decomposes. &lt;a href=&quot;https://www.researchgate.net/profile/Emine_Kara/publication/222149241_Rates_of_decomposition_of_plant_residues_and_available_nitrogen_in_soil_related_to_residue_composition_through_simulation_of_carbon_and_nitrogen_turnover/links/54934ea30cf22d7925da2ecb.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hadas, et al., 2002&lt;/a&gt; has experimental data from plants with C:N ratios from 11:1 to 136:1. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In summary, most carbon ends up in microbial biomass or as CO$_2$. If the process is allowed to proceed to infinity, then presumably, the microbial biomass will itself be decomposed by other microbes until all of it in the form of CO$_2$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The nitrogen is mineralized, first into NH$_4^+$, then NO$_2^-$ and eventually all into NO$_3^-$ by various decomposing microbes. Normally these ions are attached to something else that they got from the soil and thus enter the soil. In the regular nitrogen cycle, the ions that eventually end up as NO$_3^-$ will be processed by other bacteria into atmospheric nitrogen (N$_2$). So, if decomposition proceeds to infinity, all the nitrogen would be expected to return to the atmosphere eventually too. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That leaves us with the small amounts of other biologically common elements such as phosoprous, calcium, etc. This will be the only stuff left. From &lt;a href=&quot;https://naldc.nal.usda.gov/download/IND43966853/PDF&quot; rel=&quot;nofollow noreferrer&quot;&gt;Latshaw, 1934&lt;/a&gt; (side note, not the oldest paper reference I've seen on Stack Exchange, but close!), and the chemical composition of a corn plant, considering all parts of the plant together, there is on average 44.9% oxygen, 44.0% carbon, 6.3% hydrogen, and 1.5% nitrogen by mass; all of these would be expected to leave as as gasses. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of the remainder, representing 3.3% of the mass, probably most of that would stay. Whatever elements are left are most likely to form molecules with oxygen, since it is freely available in the air and likes to react with just about anything. Silicon, potassium and calcium don't seem to have any likely gaseous forms they could take, while sulfur (SO$_2$) and phosphorous (possibly P$_2$H$_4$) might take some more volatile forms. In the end, little will be left of the former plant, just a scattered residue of oxidized minerals, around 3% of the original mass.&lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="6703" LastEditDate="2016-12-21T20:13:36.380" LastActivityDate="2016-12-21T20:13:36.380" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9329" PostTypeId="2" ParentId="8686" CreationDate="2016-12-21T20:06:23.323" Score="2" Body="&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.4319/lo.1997.42.1.0001/pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Behrenfeld and Falkowski, 1997&lt;/a&gt; have maps of cholorphyll concentration for the entire world on pages 11-13 of the linked paper. The maps are divided by into yearly concentration and seasonal concentration, with the maps filled out from experimental data by two different modeling methods. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These maps are in mg C / m$^2$ / year, but they offer the normalization of $$\frac{4.6 \text{mg C / hour}}{1\text{ mg Chlorophyll}}.$$ Chlorophyll production varies by optical depth, which is the distance that light can penetrate into the water. Optical depth depends on various characteristics of the seawater like sediment node, so it doesn't have an exact analogue to water depth. However, Fig 1A supports a conclusion that plankton production is reduced by an order of magnitude at depth of 20 meters, and by 2 orders of magnitude by 60 meters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we confine the chlorophyll to entirely the top 60m of the ocean, then we can convert $$\frac{1 \text{ mg C}}{\text{m}^2\cdot\text{year}}\cdot\frac{1 \text{ mg Chlorophyll}}{4.6\text{ mg C / hour}}\cdot \frac{1 \text{year}}{8760 \text{ hours}} \cdot \frac{1}{60 \text{m}}= \frac{0.41 \text{ ng Chlorophyll}}{\text{m}^3}.$$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using this convertion specifically on map A on page 11 of the linked paper, I get for your answers:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Open ocean in general: 75-150 g C/m$^2$/year $\rightarrow$ &lt;strong&gt;30-60 $\mu$g/m$^3$&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;N. Atlantic Ocean: 150-250 g C/m$^2$/year $\rightarrow$ &lt;strong&gt;60-100 $\mu$g/m$^3$&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;Coastal waters around the UK: 300-450 g C/m$^2$/year $\rightarrow$ &lt;strong&gt;125-185 $\mu$g/m$^3$&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;Equatorial waters: 100-200 g C/m$^2$/year $\rightarrow$ &lt;strong&gt;40-80 $\mu$g/m$^3$&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2016-12-21T20:06:23.323" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9330" PostTypeId="2" ParentId="9316" CreationDate="2016-12-22T13:09:39.923" Score="2" Body="&lt;p&gt;Despite the obvious red colour &lt;em&gt;Trentepohlia annulata&lt;/em&gt; and numerous related species are blue-green algae. The red colouring comes from beta caroteine and related natural pigments. There are very many such common pigments in nature, comprising scores if not hundreds of compounds, ranging in colour from yellow through orange, red and purple, eg. from lichens on wood bark, carrots, saffron, beetroot, and certain bird feathers/beaks - to name but a few sources. The red colourant masks the natural greenish hue of the original organism. It is a strong colouring compound which is why beta-caroteine and its derivatives are sometimes used in food colouring.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to the concentration of algal spores, this is difficult to determine because the colour intensity is a function of the pH, exact chemical species of pigment, biological viability of the spores, and presence/absence of co-variable interacting ions in the water. As a &lt;em&gt;very rough&lt;/em&gt; guide I would estimate that the concentration of pigment (not the concentration of spores) is likely to be in the order of 20 to 200 mg/l. For a bit of fun, you could get some beta-carotein-based food colourant and experiment on concentration and colour &lt;em&gt;vs.&lt;/em&gt; pH.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Trentepohlia annulata&lt;/em&gt; and related algal species are pretty much ubiquitous in wet tropical and subtropical environments, but they don't like cold weather. The red colour in your photograph is extraordinary and very unusual. I would assume that conditions of nutrient availability, pH and temperature would have to be 'just right'. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My last comment is pure conjecture on my part - and I may be way off beam here - but maybe the intense red colour could be brought on by the physics of raindrop formation. If very moist warm air, rich in &lt;em&gt;T.a&lt;/em&gt; algal cells was rapidly lofted in a tropical convection cell, the sudden cooling could kill off the algal cells, thereby rupturing the cell membranes, and triggering catastrophic release into solution of carotein-related pigment into resulting raindrops, which would normally pass unnoticed. Further concentration could occur by evaporative reduction of raindrop volume, especially if most of the rainfall dissipated into the atmosphere as so-called 'occult rainfall'. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-12-22T13:09:39.923" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9332" PostTypeId="2" ParentId="6957" CreationDate="2016-12-23T08:38:06.260" Score="2" Body="&lt;p&gt;&lt;a href=&quot;http://www.envexp.com/labmatters/236-understanding-biochemical-oxygen-demand-bod&quot; rel=&quot;nofollow noreferrer&quot;&gt;Biological Oxygen demand&lt;/a&gt; increases with accumulation of decaying organic matter in a water system. This means that BOD is highest where there is high concentration of decomposing organic matter in that system.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What is the relation between biological oxygen demand (BOD) and depth?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The answer may vary as in some cases organic matter floats on upper columns of water and can be decomposed readily by aerobic microorganisms manifesting an increased BOD. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, &lt;a href=&quot;http://www.ajol.info/index.php/njt/article/viewFile/123371/112914&amp;amp;ved=0ahUKEwj7pZnU8YnRAhWGOFAKHTMFA4IQFggpMAE&amp;amp;usg=AFQjCNEnuF2BjcS55dH4W9v-T5XSPnFtyA&amp;amp;sig2=PGV0zknU20V_L1XvONSM5g&quot; rel=&quot;nofollow noreferrer&quot;&gt;this study &lt;/a&gt;  which was conducted using waste water from stabilization ponds (depths ranging from 0-5m) shows that there is an increase in the Biological Oxygen Demand with increasing depth and this can be attributed to the settling down of organic matter in these ponds.&lt;/p&gt;&#xA;" OwnerUserId="5273" LastEditorUserId="5273" LastEditDate="2016-12-25T16:18:40.217" LastActivityDate="2016-12-25T16:18:40.217" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9333" PostTypeId="1" CreationDate="2016-12-23T20:03:43.987" Score="1" ViewCount="26" Body="&lt;p&gt;Has there been loss of natural habitat in north England or Britain in general over the past years? If there was, what is the loss in percentage? A reference would be highly appreciated&lt;/p&gt;&#xA;" OwnerUserId="7184" LastActivityDate="2016-12-23T20:03:43.987" Title="Has there been loss of natural habitat in north England?" Tags="|homework|gis|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9334" PostTypeId="1" CreationDate="2016-12-23T21:08:37.567" Score="1" ViewCount="22" Body="&lt;p&gt;I am using GIS to undertake a small research on the loss of natural habitat in north England. I will be using Supervised Classification where I train the system on a few examples, e.g.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;shallow water&lt;/li&gt;&#xA;&lt;li&gt;deep water&lt;/li&gt;&#xA;&lt;li&gt;forest&lt;/li&gt;&#xA;&lt;li&gt;built area&#xA;then based on a satellite image the software will create a map with these categories throughout.&#xA;There is no detailed research question but I would like to have something a bit more detailed than just built environment, vegetation and water. On the other hand there is no need for tens of categories.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;What categories should I use for this analysis and why?&lt;/p&gt;&#xA;" OwnerUserId="7184" LastActivityDate="2016-12-23T21:08:37.567" Title="Categories for supervised classification, wildlife analysis" Tags="|homework|ecology|gis|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9335" PostTypeId="1" CreationDate="2016-12-23T21:32:36.710" Score="3" ViewCount="26" Body="&lt;p&gt;What methods are there to research loss of natural habitat?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know of supervised image classification in GIS but what other methods are commonly used in research?&lt;/p&gt;&#xA;" OwnerUserId="7184" LastActivityDate="2016-12-23T21:32:36.710" Title="Methods in researching loss of natural habitat" Tags="|ecology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9337" PostTypeId="1" CreationDate="2016-12-24T14:47:31.093" Score="5" ViewCount="1941" Body="&lt;p&gt;I've been in Ukraine (Kiev) in the winter, and this winter was snowy and rainy but still I've never seen or heard neither &lt;strong&gt;lightning nor thunders&lt;/strong&gt; there. What is the explanation for that?&lt;/p&gt;&#xA;&lt;p&gt;I thought about two possibilities:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;There are both, and I simply didn't see and listened. (It's strange I had there windows and the sky was in front of me)&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Indeed there are neither lightning nor thunder in this place.&#xA;Then I would ask if there are another places like that.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="7190" LastEditorUserId="2470" LastEditDate="2023-02-28T18:30:01.253" LastActivityDate="2023-02-28T19:12:02.207" Title="Are there places with rain and snow but no lightning and thunder?" Tags="|lightning|thunderstorm|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="9338" PostTypeId="1" CreationDate="2016-12-24T16:35:33.587" Score="1" ViewCount="42" Body="&lt;p&gt;I once read that about 50% of the emitted temperature of the Earth is due to radio active decay of uranium and pollonium. Is this true and how would this be done as most of the decay energy are gammarays? Do we really get some heat of these particles?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastActivityDate="2016-12-24T16:35:33.587" Title="What would the temperature be on Earth without the sun from radio active decay in the Earth?" Tags="|geology|" AnswerCount="0" CommentCount="2" ClosedDate="2016-12-25T20:50:06.863" ContentLicense="CC BY-SA 3.0" />
  <row Id="9340" PostTypeId="1" AcceptedAnswerId="9350" CreationDate="2016-12-25T16:29:27.163" Score="1" ViewCount="362" Body="&lt;p&gt;I have read that the Earth has undergone five ice ages, the latest one is the Quaternary glaciation. I know that in the ice age there are glacial periods and interglacial periods, and we are currently in an interglacial, I want to make sense what is the effect of those succsessive periods on the life on Earth. Because in my text book I read that the soil has grown and become fertile since 20 thousand years ago, since the interglacial period started. But what made this change in the soil? and why it became suitable for farming? And is it a costant thing that the soil become rich and good in the interglacials of all ice ages?&lt;/p&gt;&#xA;" OwnerUserId="6908" LastEditorUserId="11908" LastEditDate="2019-03-13T05:20:23.290" LastActivityDate="2019-03-13T05:20:23.290" Title="Reults of the glacials and interglacials of the ice age on the soil" Tags="|geology|glaciology|ice|ice-age|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9341" PostTypeId="1" CreationDate="2016-12-25T17:57:35.267" Score="4" ViewCount="390" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/G0drq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G0drq.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have a plot of the magnetic field (y-axis) over time (x-axis), one measure each hour (Dst - Disturbance Storm-Time). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From time to time, there is a negative peak, which indicates a magnetic storm. The more it goes down the bigger the storm. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the physical meaning of the integral of it (nT x h)?&lt;/p&gt;&#xA;" OwnerUserId="7194" LastEditorUserId="2536" LastEditDate="2017-06-12T15:18:13.317" LastActivityDate="2017-06-12T15:18:13.317" Title="What is the meaning of integral of negative magnetic field (nT) over time?" Tags="|geomagnetism|solar-terrestrial-physics|electromagnetism|magnetosphere|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9342" PostTypeId="1" CreationDate="2016-12-25T21:19:05.727" Score="8" ViewCount="594" Body="&lt;p&gt;I have had much success with old textbooks in mathematics. Generally, for any branch of mathematics that I (as a non-mathematician) would like to learn or re-learn, I can buy a classic textbook from the 1970s, and it will be accurate and cheap.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, as a computer scientist, I know that this is not a great strategy for all subjects. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am interested in learning more about the geology of the Earth and the other rocky bodies of the solar system. If I buy old editions of textbooks (such as &lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/0023851503&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;, &lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/0023494808&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;, or &lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/0721640265&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;), what am I going to be missing in terms of up to date theory? Am I likely to purchasing a textbook full of no-longer accepted theories or disproven facts?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a follow up question, if text books like the one from 1979 are too far out of date, how old can I generally go to get an accurate text?&lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="2536" LastEditDate="2017-04-28T03:11:54.600" LastActivityDate="2020-03-16T12:05:27.700" Title="Are old geophysics textbooks useful?" Tags="|geology|geophysics|planetary-science|geodynamics|history-of-science|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9344" PostTypeId="2" ParentId="9342" CreationDate="2016-12-26T03:11:36.287" Score="11" Body="&lt;p&gt;Mathematics and computer science are exact sciences. If something is discovered and known, it is not wrong. With time, there may be better or new ways of doing something, but the old stuff is still correct. This is why you can get a textbook from the 60s and study it. Cauchy's laws are still correct and Euler's theorem is still correct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is not the case with earth science (which I expand from your &quot;geophysics&quot;). Just about every paper published in the field of earth science follows the theme of &quot;we thought something but now we found it's actually wrong&quot;. And there are hundreds of those per year. While math textbooks teach facts, earth science textbooks present the opinion of the author at the time of writing, which is also commonly the prevailing view in the broader earth science community, but it doesn't have to. In most cases old textbooks are not going to be &lt;em&gt;that&lt;/em&gt; bad, but there will be abundant accuracies and omissions. If you go back enough, you might finds that are completely wrong (plate tectonics was only accepted in the 1960s!). But it doesn't have to be this: take subduction zones. The understanding of what happens to slabs once they subduct was only somewhat understood (at least on an undergrad textbook level) in the past 15 years. Whether the slabs themselves melt or not isn't even known today (even though textbooks will mostly say they don't: again, this is the opinion of the author). The inner structure of the earth as understood from seismicity and tomography is being refined every year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In your textbook links you gave the example of planetary science and volcanism. In the case of planetary science, every time there is a new mission we learn so much. Just example of some discoveries of extraterrestrial volcanoes: Io in &lt;a href=&quot;http://dx.doi.org/10.1038/280733a0&quot; rel=&quot;nofollow noreferrer&quot;&gt;1979&lt;/a&gt;, Triton in &lt;a href=&quot;http://dx.doi.org/10.1126/science.246.4936.1422&quot; rel=&quot;nofollow noreferrer&quot;&gt;1989&lt;/a&gt;, and Titan in &lt;a href=&quot;http://dx.doi.org/10.1038/nature03596&quot; rel=&quot;nofollow noreferrer&quot;&gt;2005&lt;/a&gt;. Also think of the latest understanding of minor planets, comets and asteroids obtained in the past 5 years. This is not something you will find in even moderately new textbooks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To sum it up, old earth science textbooks are not completely wrong. But they are wrong to some degree, and they most probably contain a lot of omissions (depends on the exact sub-field). Online sources are usually much better for that. Maybe start with related MOOCs? These can be good starting points. Even if you prefer reading and not watching videos, you can usually find a list of (somewhat) up to date sources there.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2020-03-16T12:05:27.700" LastActivityDate="2020-03-16T12:05:27.700" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="9345" PostTypeId="2" ParentId="2355" CreationDate="2016-12-26T04:38:53.553" Score="-2" Body="&lt;p&gt;Wackiest answer:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It has all the hallmarks of a plasma discharge. Burn marks around the rim next to the saw tooth serrations resemble EDM machining scars.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bLJFH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bLJFH.jpg&quot; alt=&quot;EDM machining scars&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bKIES.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bKIES.jpg&quot; alt=&quot;crater walls show characteristic scalloping of electrical discharge&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rn8Ky.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rn8Ky.jpg&quot; alt=&quot;vertical walls cut by plasma, saw tooth edge results from hypersonic blast&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sWtLJ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sWtLJ.jpg&quot; alt=&quot;large crater in Mexico showing same triangular shapes around rim&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4RwIs.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4RwIs.jpg&quot; alt=&quot;diagram of electrical discharge event, shock wave blast creates triangular shaped wave which superimposes on the surface&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are some excellent videos on youtube about electric geology if you are interested in more detailed info.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=ITtvK1wyptU&amp;amp;index=30&amp;amp;list=PLwOAYhBuU3UeYFyfm2LilZldjJd48t6IY&quot; rel=&quot;nofollow noreferrer&quot;&gt;Video about electric geology, explains arc blasted earth features&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Speculation on the cause could go wild. Some natural phenomena might account for such an event, but likely would have been easily noticed by locals, even at a great distance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There has been much chatter lately about hypersonic reentry vehicles as weapons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nationaldefensemagazine.org/archive/2015/August/Pages/HypersonicWeaponsRaceGathersSpeed.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.nationaldefensemagazine.org/archive/2015/August/Pages/HypersonicWeaponsRaceGathersSpeed.aspx&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://rbth.com/defence/2016/09/27/russia-could-get-hypersonic-weapons-by-early-2020s_633689&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://rbth.com/defence/2016/09/27/russia-could-get-hypersonic-weapons-by-early-2020s_633689&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Such a device creates very different conditions in the atmosphere around it as it forms a plasma from the high speeds involved. It is likely that such weapons are being tested, far from man, but somewhere accessible. A hole that size would only require a test sized vehicle, a scale model maybe. And with such obvious success, you might want to leak pics to notify the enemy of your capability, because the best defense is a good offence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;/kook&lt;/p&gt;&#xA;" OwnerUserId="7195" LastEditorUserId="7195" LastEditDate="2016-12-26T18:03:29.027" LastActivityDate="2016-12-26T18:03:29.027" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9347" PostTypeId="1" CreationDate="2016-12-26T15:37:46.580" Score="5" ViewCount="345" Body="&lt;p&gt;I'm currently attempting to design a water recycling solution for a carwash in a tropical country that currently uses up to 30m$^3$ (8,000 gallons US) of water in 12 hours.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Based on my research in the subject the best way of filtering this water is by using wetlands after having passed the water through an initial filtering stage to get rid of any plastics in it, however although I have been looking around the web I haven't found any equation I could use to calculate the flowrate of water through a wetland.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can find an image of the wetland filter I'm thinking of using here: &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Tilley_et_al_2014_Schematic_of_the_Horizontal_Subsurface_Flow_Constructed_Wetland.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Schematic of the Horizontal Subsurface Flow Constructed Wetland (Wikipedia)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just in case it's not clear, I am not attempting to make the water drinkable I just want to make the water clean enough so it can be used to wash cars again. The water will be stored at most 12 hours during the night so it can be used again in the morning.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any advice in the matter would be greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="7198" LastEditorUserId="2536" LastEditDate="2017-01-26T13:59:22.773" LastActivityDate="2018-03-25T07:26:25.430" Title="Calculate flow rate of wetland for gray water treatment" Tags="|water|environmental-protection|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9348" PostTypeId="2" ParentId="9347" CreationDate="2016-12-27T01:42:39.233" Score="2" Body="&lt;p&gt;Nice 'green' idea, but I don't think it will work. Wetlands are good for filtering out solids. Dissolved molecules, like detergents will take much longer to degrade by microbial and UV degradation, by which time coloured organics in the wetland will develop, like fulvic, humic and tannic acids. These might be OK for washing dark coloured cars, but I doubt if you will get away with this on white or light-coloured cars. If you have the roof area then rainwater harvesting in a large tank would be a better bet - also, the rainwater would be soft, so less cleaning agent would be necessary. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-12-27T01:42:39.233" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9349" PostTypeId="1" CreationDate="2016-12-27T01:58:41.877" Score="3" ViewCount="22" Body="&lt;p&gt;I'm doing a project using two days worth of GOES 13 satellite data during June, 2016.  I'm trying to make an HD animation using data from bands 1 and 4.  I've been using the Weather &amp;amp; Climate Toolkit that NOAA provides, but I am finding inferior quality uncompressed AVI output.  It doesn't matter what background I'm using, but it seems as if the image data has it's lowest and highest histogram points clipped.  I've tried as many settings as I can use in the WCT program, but nothing changes.  However, if I were to make an AVI using GIF format, the result is much better, but this will take a lot longer since I'll have to import the GIF's into a different program and assemble each frame into an AVI.  Since using WCT is easier, my question is: how do I improve the AVI result and if it can't be done with WCT, are there other free programs I could try that would do the same thing with the AREA data (produce a quality AVI)?  Thank you.   &lt;/p&gt;&#xA;" OwnerUserId="7202" LastActivityDate="2016-12-27T01:58:41.877" Title="improving image quality from AREA GOES imager data using WCT or other program?" Tags="|meteorology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9350" PostTypeId="2" ParentId="9340" CreationDate="2016-12-27T02:01:44.700" Score="0" Body="&lt;p&gt;First a comment on the number of ice ages - one could say 5 to 7 major ice ages, depending upon how one defines an ice age, and several more minor ice-ages, with some debate as to whether some are sufficiently separated in time to be regarded as two ice ages. &#xA;Most of the northern hemisphere has been emerging from the most recent ice age over the past 10000 to 12,000 years, but by no means at a constant rate, with some short-term reversals. As regards soil formation, it is only the most recent ice age that is of relevance - older palaeosols have been either eroded or lithified.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How long does it take for soil to form? That is primarily a function of climate, and secondarily a function of weathering lithology. That is, many millennia for cold dry climates, or as little as a decade or so for hot wet conditions. Soils take many years to form on limestone, quartzite, granite and some other resistant rocks, but are rapid on recent basic rocks such as volcanic ash. The weathering rate of different minerals varies over many orders of magnitude, and is a combination of chemical and biological processes which is far too complicated to discuss here. I suggest you read a good book on weathering processes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding soil fertility, this is also rather complex, but obviously continuous cropping will tend to remove organic carbon, organically available phosphate and potassium, not to mention other trace elements, thereby leaving the soil less fertile unless very well managed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ice ages are not 'normal' in the geological history, and it will take tens to hundreds of millennia for a normal soil quasi-equilibrium to be reached. This 'equilibrium will also be lost both by human intervention and by accelerated climate change. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-12-27T02:01:44.700" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9354" PostTypeId="1" CreationDate="2016-12-27T06:03:37.697" Score="5" ViewCount="129" Body="&lt;p&gt;Look at the photo below. Presumably, the river bed is a smooth shape. Therefore, it should be possible to infer the depth of the water from the photo, right?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not even an amateur of geo-science. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am willing to listen to the experts. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/h3CCn.jpg&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/h3CCn.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7206" LastEditorUserId="18081" LastEditDate="2022-08-04T08:36:21.707" LastActivityDate="2022-08-04T08:36:21.707" Title="Is it possible to infer the depth of a river from the shapes of the islands and the banks?" Tags="|geology|geography|rivers|geomorphology|bathymetry|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9355" PostTypeId="1" AcceptedAnswerId="9358" CreationDate="2016-12-27T11:33:10.897" Score="3" ViewCount="236" Body="&lt;p&gt;I'm unable to find good sources to make myself an &lt;code&gt;AQI(Air quality Index)&lt;/code&gt; measuring device. All I was able to find was the way it is calculated in different regions. But I need some help with the technology used to measure the concentrations of different pollutants like &lt;code&gt;SO2, NOx, PM10, PM2.5, etc.&lt;/code&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any good papers or patents on the technology used to measure the AQI?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any help is appreciated. Thanks.&lt;/p&gt;&#xA;" OwnerUserId="7208" LastEditorUserId="6031" LastEditDate="2019-04-21T05:26:25.407" LastActivityDate="2019-07-10T01:50:32.527" Title="How can I test the Air Quality?" Tags="|air-pollution|pollution|air-quality|technology|pm2.5|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9356" PostTypeId="5" CreationDate="2016-12-27T11:44:32.780" Score="0" Body="&lt;p&gt;When exposed to particle pollution, people with heart or lung diseases and older adults are more likely to visit emergency rooms, be admitted to hospitals, or in some cases, even die. we can prevent the side-effects by checking the Air Quality in the surroundings and take some preventive measures.&lt;/p&gt;&#xA;" OwnerUserId="7208" LastEditorUserId="7208" LastEditDate="2016-12-27T14:24:55.157" LastActivityDate="2016-12-27T14:24:55.157" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9357" PostTypeId="4" CreationDate="2016-12-27T11:44:32.780" Score="0" Body="Air pollution is a major issue these days and we can prevent the side-effects by checking the Air Quality in the surroundings and take some preventive measures." OwnerUserId="7208" LastEditorUserId="7208" LastEditDate="2016-12-27T14:24:39.317" LastActivityDate="2016-12-27T14:24:39.317" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9358" PostTypeId="2" ParentId="9355" CreationDate="2016-12-27T15:28:51.940" Score="5" Body="&lt;p&gt;The AQI calculation does not require that all pollutants be measured.  Instead, it uses the pollutants that are available and then uses a function (chosen by the overarching regulatory agency) that equates health risk categories to the pollutant concentrations.  The pollutant with the highest health risk (at present concentrations) will effectively determine the corresponding AQI.  See here for &lt;a href=&quot;https://en.wikipedia.org/wiki/Air_quality_index#United_States&quot; rel=&quot;noreferrer&quot;&gt;how the USA EPA computes their AQI&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to detect the most commonly monitored pollutants, you would need an ozone analyzer and a PM2.5 monitor.  This is quite expensive.  A good single-pollutant monitor will cost thousands of dollars to purchase and many continuing costs.  You will also need calibration equipment and standards.  Depending on what AQI network you will be using as a reference, the model of instrument that you use will have to meet certain specifications in order for the data to be valid.  &lt;a href=&quot;http://www.teledyne-api.com/&quot; rel=&quot;noreferrer&quot;&gt;Teledyne&lt;/a&gt; is an example of a company that makes equipment that would meet the qualifications for the USA AirNOW network.  You may also find of interest their nice &lt;a href=&quot;https://www.airnow.gov/index.cfm/images/index.cfm?action=airnow.calculator&quot; rel=&quot;noreferrer&quot;&gt;AQI calculator&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2016-12-27T15:28:51.940" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="9360" PostTypeId="1" CreationDate="2016-12-27T17:33:21.057" Score="7" ViewCount="621" Body="&lt;p&gt;I heard about the georeactor hypothesis (Herndon, 1993), which claims that there is a natural atomic fission reactor in the Earth's core giving rise to the geomagnetic field. Further, Herndon claims that this reactor will shut down, causing Earth's magnetic field to disappear at some time between a hundred years to a billion years from now. Is this possible?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Herndon, J. M. (1993). Feasibility of a nuclear fission reactor at the center of the Earth as the energy source for the geomagnetic field. &lt;em&gt;Journal of geomagnetism and geoelectricity&lt;/em&gt;, 45(5), 423-437. &lt;a href=&quot;http://www.nuclearplanet.com/Herndon%20JGG93.pdf&quot; rel=&quot;noreferrer&quot;&gt;Link&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7210" LastEditorUserId="-1" LastEditDate="2016-12-29T20:21:07.903" LastActivityDate="2016-12-29T20:21:07.903" Title="Does Earth's magnetic field arise from a fission reactor in its core?" Tags="|geothermal-heat|core|geomagnetism|radioactivity|uranium|" AnswerCount="1" CommentCount="15" ContentLicense="CC BY-SA 3.0" />
  <row Id="9361" PostTypeId="1" CreationDate="2016-12-27T22:38:23.573" Score="20" ViewCount="10919" Body="&lt;p&gt;The ancient fortress of &lt;a href=&quot;https://en.wikipedia.org/wiki/Masada&quot; rel=&quot;noreferrer&quot;&gt;Masada&lt;/a&gt; is currently so dry and forbidding that is hard to imagine anyone living there. Was the climate in the surrounding area more wet 2000 years ago, or was it as much a desert as it is now?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2016-12-28T13:38:43.037" Title="Was Judea as desertified 2000 years ago as it is now?" Tags="|climate-change|paleoclimatology|desert|" AnswerCount="4" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9362" PostTypeId="2" ParentId="9361" CreationDate="2016-12-28T00:45:35.890" Score="28" Body="&lt;p&gt;There has always been a strong north-south rainfall gradient from approximately the Golan Heights (high rainfall), through Judaea and southwards into the arid Sinai desert. We know that this gradient once had a higher rainfall because there are abundant rainfall harvesting and groundwater collection structures, built by the Nabatean civilization about 400 BC to 100 AD. They are now long defunct because of climatic desiccation, but are characteristic of dry regions with marginal cultivation. Similar working structures can now be found in Oman, Iran and parts of north Africa. So it is reasonable to deduce that the region was once significantly wetter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to this overarching climatic gradient there is a very strong local rainfall gradient from the Israeli Highlands in the west, about 1100 mm, to the Dead Sea-Rift Valley in the east which receives about 100 mm per year. This is a rain shadow effect from the prevailing Mediterranean airflow to further east into the Arabian desert - obvious from the vegetation density on Google Earth. Masada currently receives about 200 mm per year, but it is very erratic, with huge inter-annual variability. One study of the Negev and adjacent dry areas concluded that the spotty distribution of annual rainfall doesn't average out - at least, not on any time-scale useful to humans. Because of its position in an intense rain-shadow, Masada will always have been dry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two potential sources of water supply to places like Masada; springs, and ephemeral (very unreliable) flash floods. The springs are groundwater which has percolated through the limestone massif from the Israeli highlands around Jerusalem,. Hebron, etc. There are currently no springs in the immediate vicinity of Masada. There may once have been a spring under higher water-table conditions, but none that we know of historically. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The solution used to supply Masada was to build two dams in canyons draining the Israeli highlands. Ephemeral flash floods were thereby intercepted and conveyed by gravity-drained aqueducts to tanks dug deep inside the Masada citadel. These tanks were of about 30 to 35 cubic metres capacity, so even allowing for evaporative and seepage losses in the aqueduct, the water supply could be topped up - provided the frequency of flash flood was sufficient. Even today it is likely that flash-floods would have been of adequate frequency. Under the slightly wetter regime of 2000 years ago, it is near certain that there would have been more than sufficient water every year. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, there are no rainfall records from so far back, but some interesting general climatic inferences may be found in Issar A.S. (1990), 'Water Shall Flow from the Rock'. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2016-12-28T03:09:40.630" LastActivityDate="2016-12-28T03:09:40.630" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9363" PostTypeId="2" ParentId="9360" CreationDate="2016-12-28T01:14:08.110" Score="14" Body="&lt;p&gt;The conventional explanation for the Earth's magnetic field is that some combination of differential rotation and/or convection occurs in the Earth's outer core, primarily in molten iron-nickel (+ sulphur, hydrogen etc.), which acts as a kind of dynamo. Whilst we can't prove it by direct observation, this seems an eminently plausible mechanism. If this is true, then the heat of the core will eventually dissipate, resulting in freezing of the core and cessation of the Earth's magnetic field. The existing heat is partly primordial and partly radiogenic from the decay of U, Th and K, and will take &lt;em&gt;many&lt;/em&gt; billions of years to dissipate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The georeactor hypothesis requires a critical mass of uranium at the centre of the Earth to start up and maintain a nuclear reaction. There are two reasons why this hypothesis is seldom taken seriously except by Herndon himself. Firstly, in order for uranium to reach criticality it has to be a very high concentration of uranium. There is no known concentration mechanism which could achieve this in the Earth's core, whereas there are many reasons to believe that the uranium would be dispersed or 'poisoned' by lead and other heavy metals. Whilst the pressure at the Earth's core would be immense, gravitational separation, i.e. density fractionation, would be almost non-existent. Secondly, if this hypothesis was correct we would expect to see a huge flux of anti-neutrinos in such detectors as the super Kamiokande. We don't. So I'm not losing any sleep at the prospect of the Earth losing it's magnetism within the next billion years. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-12-28T01:14:08.110" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9364" PostTypeId="2" ParentId="9361" CreationDate="2016-12-28T02:46:17.523" Score="6" Body="&lt;p&gt;Gordon Stanger covers the climate aspects well in his answer, but I thought I'd chime in with an answer to the &quot;was it as much a desert as it is now?&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While I'm not aware of any archaeological evidence for the agriculture in the land surrounding Masada at the time of the siege, there are several factors that may have, at that time, made the area less 'deserty.'&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two in particular I want to mention. The first are &lt;a href=&quot;http://www.waterhistory.org/histories/qanats/qanats.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;qanats&lt;/a&gt;. This technology spread from Persia around ~500 BC and quite impressive ones were built by the Romans in dry places, like &lt;a href=&quot;http://www.spiegel.de/international/world/rome-s-tremendous-tunnel-the-ancient-world-s-longest-underground-aqueduct-a-612718.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one&lt;/a&gt; from modern day Jordan. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Masada is in a cliff overlooking the Dead Sea, but the top of the fortress is only about 60 meters above sea level; the surrounding land is much lower. This puts it in a good position to receive water from nearby groundwater at higher elevation. As can be seen in &lt;a href=&quot;https://www.google.com/maps/@31.3029125,35.3292351,14z/data=!5m1!1e4&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google Maps&lt;/a&gt;, The land rises 200m in 2.5 km to the West, and 400m in about 5.5 km. Google Maps even indicate the course of several wadis that flow in the general direction of Masada which could be used as the basis for a partially underground irrigation system. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Qanats take a lot of work to build and maintain, but in a land where there is cheap labor and little water, it can be worth it to build them. The Middle East at the time had plenty of desert adapted trees that could thrive with a little irrigation (almonds, olive, carob, date, pistachio; all mentioned in the Bible), so it is entirely possible that there were groves of desert trees in the land around Masada.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This brings us to the second point: tree cover. The tree cover currently existing in the area around Masada (i.e. none) doesn't have to be the tree cover that was always there. Trees being rare in the southern Levant, they were always under pressure for use as firewood, and their regrowth was limited by grazing, especially by goats. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are several trees (large shrubs really) that &lt;em&gt;can&lt;/em&gt; grow in such hot and dry conditions, as they are present in the rest of the Negev desert in Israel, such as &lt;em&gt;Acacia&lt;/em&gt;, &lt;em&gt;Pistachia&lt;/em&gt;, and &lt;em&gt;Tamarix&lt;/em&gt;. &lt;em&gt;Acacia&lt;/em&gt; in particular may be a &lt;a href=&quot;https://www.researchgate.net/profile/Zuzana_Muenzbergova/publication/201999645_Acacia_trees_as_keystone_species_in_Negev_desert_ecosystems/links/54b5048a0cf2318f0f970c9b.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;keystone species&lt;/a&gt;, such that higher, ancient levels of tree cover could have encouraged a generally greener landscape.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In conclusion, while the area around Masada is barren now, it does not have to have been 2000 years ago. There were labor intensive irrigation techniques and tree crops available to make successful farming a possibility, and lower firewood and grazing pressure from a lower population may have allowed the wilderness areas to have been greener than they are today. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="6703" LastEditDate="2016-12-28T13:28:43.277" LastActivityDate="2016-12-28T13:28:43.277" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9365" PostTypeId="2" ParentId="9361" CreationDate="2016-12-28T07:08:33.310" Score="11" Body="&lt;p&gt;tldr: It was also dry back then, which is why the people living there were rebels and not the rich elite.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;I'd like to add a few points to Gordon's answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First of all, Masada is on the western edge of the Judea Desert, and therefore it is dry now and was extremely dry back then. The water supply to it was based on abundant water reservoirs that were built in and around Masada to trap flood water. Here is one (&lt;a href=&quot;https://he.wikipedia.org/wiki/%D7%A7%D7%95%D7%91%D7%A5:PikiWiki_Israel_6830_Masada_-_Northern_Water_Reservoir.jpg&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QqVD5.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QqVD5.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It doesn't rain a lot there, but once it rains, it rains a lot in a very short time. Being a native of the Negev Desert, I know this very well. They just had to trap all of the water, and then you have lots of water for long enough.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, you are asking:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The ancient fortress of Masada is currently so dry and forbidding that&#xA;  is hard to imagine anyone living there.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is exactly the reason it exists. Masada wasn't a holiday town for the rich, and people didn't think of it as a particularly good place to live. Even the nearby modern town of Arad is considered as a very remote and unwelcoming place to live in by most Israelis. Masada was a place where outcasts, outlaws and rebels lived. The people living there during the famous Roman siege were not the mainstream Jews living in most of Judea at that time. They were considered outlaws even by the Jewish administration in Jerusalem and elsewhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The dryness and remoteness of the area was an asset: no one even wanted to hunt them down over there. That is, unless you get someone really pissed off (such as the Roman Empire) and they decide to end it in the famous siege. The dryness was also helping the defenders: they had access to the water reservoirs while the attackers did not.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-12-28T07:08:33.310" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9366" PostTypeId="2" ParentId="9361" CreationDate="2016-12-28T13:38:43.037" Score="1" Body="&lt;p&gt;They found parchment scrolls and date-seeds (one of which was germintated!) from 2000 years ago in the Judea desert, indicating the climate was extremely dry throughout that period, allowing them to be preserved.&lt;/p&gt;&#xA;" OwnerUserId="7214" LastActivityDate="2016-12-28T13:38:43.037" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9367" PostTypeId="1" CreationDate="2016-12-28T14:39:33.067" Score="3" ViewCount="598" Body="&lt;p&gt;Nitrogen dioxide (NO2) is a relevant air pollutant i.e. by contributing to the ozone (O3) production.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was wondering if there are any plats or bacteria that fix NO2. I have read that legumes fix N2, but I'm unsure about NO2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Moreover, I was wondering whether this NO2 fixation - if existing - significantly reduced local or regional NO2 concentrations improving air quality.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone answer these questions? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="7216" LastEditorUserId="5594" LastEditDate="2016-12-29T14:35:22.880" LastActivityDate="2016-12-30T07:33:03.427" Title="Are there plants or bacteria that perform NO2 fixation and how relevant are they for improving local/regional air quality?" Tags="|nitrogen|air-quality|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="9368" PostTypeId="1" AcceptedAnswerId="9372" CreationDate="2016-12-28T17:09:19.247" Score="4" ViewCount="275" Body="&lt;p&gt;I am looking for gridded/raster estimates of daily mean temperature (ideally ambient/at 2 meter) for a public health analysis. Specifically, I want to correlate daily mortality counts with daily mean ambient temperature (globally, between the years 1990-2016). I want to use gridded data rather than nearby temperature stations to allow for some extrapolation to areas without stations with long time series (e.g. large swaths of sub-Saharan Africa).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The accuracy of temperature in terms of degrees is somewhat less important relative to the accuracy of day-to-day variability for this project.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems like the &lt;a href=&quot;https://www.esrl.noaa.gov/psd/forecasts/reforecast2/download.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;GEFS Reforcast&lt;/a&gt; and &lt;a href=&quot;https://www.esrl.noaa.gov/psd/data/gridded/data.ncep.reanalysis2.gaussian.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCEP Reanalysis&lt;/a&gt; products both provide daily mean temperature at a global extent, albeit at different spatial resolutions. I've looked at the documentation and underlying papers, but my earth science background is weak and I can't really suss out the difference between the two products.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is one product substantially better than the other for global mean ambient temperature estimates? Is there a simple difference between the two products that I've missed?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Parameters I care about (roughly in order):&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Daily measurement of mean temperature with global coverage&lt;/li&gt;&#xA;&lt;li&gt;High spatial resolution&lt;/li&gt;&#xA;&lt;li&gt;Accuracy of day to day variation (e.g. if day 1 was X degrees hotter than day 2, is that reflected?)&lt;/li&gt;&#xA;&lt;li&gt;Accuracy of daily mean estimate&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="7217" LastEditorUserId="7217" LastEditDate="2016-12-29T14:51:37.797" LastActivityDate="2016-12-30T12:21:37.200" Title="Global Gridded Daily Temperature (at 2m): difference between GEFS Reforcast and NCEP Reanalysis" Tags="|temperature|models|weather-forecasting|ncep|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9369" PostTypeId="2" ParentId="9354" CreationDate="2016-12-29T02:08:47.533" Score="5" Body="&lt;p&gt;The island morphology isn't necessarily an indication of the river's depth because the river can be bimodal, with shallows and deeply incised trenches. One thinks of the River Congo which has many islands, but depths of up to 220 metres in its main incised channel. That said, however, if the river has a multi-channel, heavily braided morphology, as in the Waimakariri in New Zealand, or the Brahmaputra in Assam, then one can be fairly certain that the intense sediment load would have filled in any deep pools (excluding local scour in sharp bends, caused by super-elevated flow). In such cases, one may assume a shallow river profile, governed only by storm-flow peak stages. &#xA;Where there are few or no islands coupled with geomorphologic indications of rapid cut back or rejuvenation, such as the Mekong upstream of its delta, then one may suspect very deep channel profiles. In general though, islands and bank morphology are not reliable indicators of a river's cross section. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="200" LastEditDate="2016-12-29T20:24:36.140" LastActivityDate="2016-12-29T20:24:36.140" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9371" PostTypeId="2" ParentId="9367" CreationDate="2016-12-30T07:33:03.427" Score="4" Body="&lt;h2&gt;NO2 uptake by plants&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;It has been observed that plants can lead to a reduction of atmospheric NO2 concentrations &lt;a href=&quot;http://www.atmos-chem-phys.net/13/773/2013/&quot; rel=&quot;nofollow noreferrer&quot;&gt;[Breuninger et al, 2013]&lt;/a&gt;. Currently, it is assumed that NO2 is taken up through stomata of plant leaves when the atmospheric NO2 concentrations are above a certain threshold. However, when the atmospheric NO2 concentrations are below this threshold, plant leave stomata act as sources for NO2. Therefore, this process is not fixation in the sense as N2 is fixed by legumes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;http://www.atmos-chem-phys.net/13/773/2013/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Breuninger et al. [2013]&lt;/a&gt; and refernces therein for details&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Canpoy reduction&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Plants do not only take up (excess) NO2 actively but they decrease the concentrations of several air pollutants by providing a lot of surface for dry deposition as Christoph stated in his comment. After deposition they may revolatilize or be washed down by rain. See e.g. &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0269749114000773&quot; rel=&quot;nofollow noreferrer&quot;&gt;Grundström and Pleijel [2014]&lt;/a&gt; for details.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Impact on air quality&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The presence of plants/trees in urban environments can reduce ambient NO2 concentrations. However, this effect is not due to NO2 fixation but due to the &lt;em&gt;canopy reduction&lt;/em&gt;/&lt;em&gt;enhanced dry deposition rate&lt;/em&gt;, which also yields a reduction of other air pollutants. See e.g. &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0269749114000773&quot; rel=&quot;nofollow noreferrer&quot;&gt;Grundström and Pleijel [2014]&lt;/a&gt;, &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S1618866704000226&quot; rel=&quot;nofollow noreferrer&quot;&gt;Yang et al [2005]&lt;/a&gt;, or &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S1352231008006262&quot; rel=&quot;nofollow noreferrer&quot;&gt;Yang et al. [2008]&lt;/a&gt; for details.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The canopy reduction is also considered in recent regional modeling studies - see e.g. &lt;a href=&quot;https://www.cmascenter.org/conference//2016/slides/arndt_implementation_canopy_2016.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Arndt et al. [2016]&lt;/a&gt; (Disclaimer: I was member of that working group until recently). It can be seen like increasing the surface roughness.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2016-12-30T07:33:03.427" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9372" PostTypeId="2" ParentId="9368" CreationDate="2016-12-30T08:15:15.897" Score="1" Body="&lt;p&gt;The fundamental difference is that you are comparing an ensemble reforecast with a reanalysis product. The assumption here is that the reanalysis provides the best possible information based on all available measurements using state of the art modelling. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reforecast on the other hand simulates the forecast process based on current models and all available observations, i.e. it only utilizes observations up to the forecast base time, then runs a forecast just like a forecast system does in real life. This might still be good but you are looking at forecasts with a lead time of 0 to 24 hours if you are using the first day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, GEFS is an ensemble system. That means that it performs several forecasts for the same days using different starting parameters. In this way, it is possible to estimate the uncertainty of the forecast system. E.g. if for a certain day the available forecasts deviate a lot, you can assume that there is higher forecast uncertainty.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a summary, I'd say that using reforecast data would require some more justification than using reanalysis data. Using the ensemble information may be a good reason to use GEFS reforecast but would also add another layer of complexity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, allow me some general comments:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Have you considered using data from other services, most notably ECMWF? The &lt;a href=&quot;http://www.ecmwf.int/en/research/climate-reanalysis/era-interim&quot; rel=&quot;nofollow noreferrer&quot;&gt;ERA-Interim&lt;/a&gt; reanalysis is quite commonly used and has very good reputation. Or, as gansub pointed out, you can consider the &lt;a href=&quot;http://jra.kishou.go.jp/JRA-55/index_en.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;reanalysis by JMA&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;No matter which product you are using, do not take the results as &quot;truth&quot;. You may find that interpolating down to an individual location requires more thought than people usually expect. For example, what happens if your location is a land location but falls into a sea pixel? This would greatly affect simulated 2m temperatures and the diurnal cycle. Using a neighbouring pixel in such cases may get you better results.&lt;/li&gt;&#xA;&lt;li&gt;Speaking of the diurnal cycle, do you really care about daily means? In this kind of studies, I have seen people distinguish between day and night-time temperatures, which appeared to me as quite crucial.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="681" LastEditorUserId="681" LastEditDate="2016-12-30T12:21:37.200" LastActivityDate="2016-12-30T12:21:37.200" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9373" PostTypeId="1" AcceptedAnswerId="9374" CreationDate="2016-12-30T08:18:03.720" Score="12" ViewCount="1425" Body="&lt;p&gt;I was surfing through &lt;a href=&quot;https://www.google.com/maps/@7.278047,45.6969249,2988m/data=!3m1!1e3&quot; rel=&quot;noreferrer&quot;&gt;Google Maps around Ethiopian desert region&lt;/a&gt; (close to the town of Werder/Wardheer) and I found this weird looking structure. It seems like a dried up lake bed, but I can't guess what the straight lines are going out of the circular thing. Any idea?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/w8P7Z.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/w8P7Z.jpg&quot; alt=&quot;Screenshot1&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FozWo.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FozWo.jpg&quot; alt=&quot;Screenshot2&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7225" LastEditorDisplayName="user20559" LastEditDate="2021-06-01T18:43:28.827" LastActivityDate="2021-06-01T18:43:28.827" Title="What is this weird looking structure in Ethiopian desert?" Tags="|geology|geography|geomorphology|desert|identification-request|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9374" PostTypeId="2" ParentId="9373" CreationDate="2016-12-30T13:23:44.757" Score="18" Body="&lt;p&gt;Zoom in for the clues. The lines are not radiating out from the village, but from the cattle kraals. These kraals are irregular enclosures built of acacia thorn, agave and other thorny bushes. The cattle are kept in these kraals at night to protect them from hyenas and packs of wild dogs. The cattle themselves are likely African longhorn or various local cross-breeds with Sebu. They are creatures of habit, walking out from the kraal in the early morning, and back in the evening. They follow the same track for several hundred metres before the cattle diverge in slightly different directions. In the more concentrated paths decades of hoof-prints erode the dusty soil, often in trenches to depths of 60 or 70 cm. When it rains, runoff drains into the paths where it collects as red mud, the latter being derived from the deep weathering of basalt. The cattle are led by villagers who each have allocated pasture land, hence the constancy of direction. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the most striking example I have seen. Often it is not as obvious because, at least in wetter areas, there is more local grass, and the cattle are tempted to disperse 'closer to home'. On the ground one can see these in many parts of East Africa, from the Simian highlands of Ethiopia to the Simiyu pastures of northern Tanzania. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-12-30T13:23:44.757" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9375" PostTypeId="1" AcceptedAnswerId="9377" CreationDate="2016-12-30T17:27:37.753" Score="5" ViewCount="4773" Body="&lt;p&gt;This question might be a bit silly, but I have to ask since I am very curious and I did not find any good answer. I visited two places, where quartz crystals (var. smoky quartz) occurs - and both sites are pretty similar and could host the same formation process.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5cHK0.jpg&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5cHK0.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is - could you explain how exactly these crystals of quartz could form in calcite veins in limestone ? Hydrothermal fluids ? What does it mean, could it be easily described ? Where did the SiO2 come from ? Was there any radiation, too ?&lt;/p&gt;&#xA;" OwnerUserId="7031" LastActivityDate="2016-12-31T01:00:11.017" Title="How does quartz form in calcite veins?" Tags="|geology|mineralogy|minerals|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9376" PostTypeId="1" CreationDate="2016-12-30T18:00:18.067" Score="7" ViewCount="140" Body="&lt;p&gt;Could the breakdown voltage of air significantly go down in very foggy weather (especially very salty fog from seawater)?  Kind of a hypothetical question, but if anyone has something on this, I'd appreciate it.&lt;/p&gt;&#xA;" OwnerUserId="7227" LastEditorUserId="6298" LastEditDate="2017-01-07T06:12:03.897" LastActivityDate="2017-01-07T06:12:03.897" Title="How does fog affect the conductivity/breakdown voltage of air?" Tags="|meteorology|water|electromagnetism|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9377" PostTypeId="2" ParentId="9375" CreationDate="2016-12-31T00:27:42.247" Score="4" Body="&lt;p&gt;Your question is &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How does quartz form in calcite veins?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But maybe a more appropriate question will be&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How does quartz &lt;em&gt;not&lt;/em&gt; form in calcite veins?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Quartz is one of the most common vein material in Earth's crust, and for a reason. SiO&lt;sub&gt;2&lt;/sub&gt; is not a particularly soluble compound at the surface, but once you get deeper it becomes extremely soluble (&lt;a href=&quot;http://geology.gsapubs.org/content/30/8/727&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1E6Eq.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1E6Eq.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The solubility of SiO&lt;sub&gt;2&lt;/sub&gt; is almost 0 at at 1 bar and 25 °C, but increases strongly with pressure and temperature. For example, at 200 °C and 2000 bar (2 kbar, 0.2 GPa, about 5–6 km depth), conditions that are reasonable for an unmetamorphosed but deeply buried limestone, you can fit about 500 mg of SiO&lt;sub&gt;2&lt;/sub&gt; in 1 kg of H2O. At atmospheric pressure that's one litre of water, but it's much less voluminous at depth. That is a lot of SiO&lt;sub&gt;2&lt;/sub&gt;! Once the fluid goes up towards the surface, it depressurises and cools, causing precipitation of quartz.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is no shortage of sources for SiO&lt;sub&gt;2&lt;/sub&gt;. It is the most common chemical component in the crust. Even in seemingly pure limestone there are more than enough impurities of silicates to provide a source for SiO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fact that quartz and calcite occur together in a vein is no problem at all. You might expect them to react, but they actually do not. Here's a diagram to show it (&lt;a href=&quot;http://serc.carleton.edu/research_education/equilibria/simplephasediagrams.html&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dBc1n.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dBc1n.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Calcite and quartz can peacefully coexist, unless it's extremely hot and then they react to form wollastonite (a Ca-silicate). This is the kind of stuff you find in high grade metamorphosed marbles, for example.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an aside, another question that may be asked is why only calcite and quartz? If hot dense water are so good in dissolving stuff? Where's the rest of the periodic table? Well, most of the elements are readily soluble in acidic fluids. In this case, the abundant calcite buffers the pH of the water to rather basic conditions, which are not that great in dissolving stuff.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2016-12-31T00:27:42.247" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9378" PostTypeId="2" ParentId="9375" CreationDate="2016-12-31T01:00:11.017" Score="1" Body="&lt;p&gt;Vein mineralization occurs when percolating groundwaters exceed saturation with respect to the mineral being precipitated. The saturation index for each mineral, defined as log(IAP/KT) may be negative-undersaturated (mineral dissolves), positive-oversaturated (mineral precipitates), or zero (nothing happens). It is a function of thermodynamic equilibrium with respect to each mineral in which the mineral chemistry has dissolved components in the groundwater. It is a bit complicated, but if you measure the redox potential, pH, temperature, and full chemical analysis of the groundwater, then you can feed the results into an open access programme such as PHREEQE or WATEQ4F, and it will tell you which minerals are oversaturated. There is also the matter of reaction kinetics, such that some minerals may be over-saturated but so sluggish to precipitate that you won't find it in the vein. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Calcite and quartz are both common, almost ubiquitous in limestone veins. Obviously, the calcite is re-precipitated limestone. The groundwater chemistry undergoes cycles according to recharge characteristics, temperature, pressure and partial pressure of CO2, so sometimes it dissolves and re-precipitates the same carbonate several times, discernible by subtle changes in dissolved Mg and Sr and isotopic composition. All limestones have differing degrees of impurities, typically from about 0.5 to 10%, of which silica is a ubiquitous component. Groundwaters typically carry dissolved silica, as silicic acid, in the concentration range of about 5 to 50 mg/litre.  Under normal temperature-pressure conditions silica / quartz precipitates or dissolves extremely slowly, but at higher pressures and temperatures the kinetics of crystallization are dramatically accelerated. So precipitation of quartz and calcite is actually quite common.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Radiation is not normally a feature unless there also happens to be dissolved uranium or high levels of potassium in the environment. Radiation does not change the basic thermodynamic controls over precipitation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS: IAP is the 'ion activity product', K is a characteristic constant unique to each phase change, and T is the temperature in degrees Kelvin.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2016-12-31T01:00:11.017" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9379" PostTypeId="1" CreationDate="2016-12-31T16:51:28.797" Score="5" ViewCount="73" Body="&lt;p&gt;In geostatistics, we can assess and analyze regionalized variables. Tectonic stresses releases in seismically active regions by occurring earthquakes. We can calculate and estimate the seismic energy released by an earthquake. Now, the question is this: Is it possible to assess 2-D or 3-D spatial variation of the seismic energy released in a region, using geostatistics rules?&lt;/p&gt;&#xA;" OwnerUserId="7228" LastEditorUserId="5594" LastEditDate="2017-01-01T10:21:25.810" LastActivityDate="2017-02-02T04:36:07.710" Title="Is &quot;seismic energy released&quot; a regionalized variable and can be analyzed using geostatistics?" Tags="|geophysics|seismology|earthquakes|tectonics|data-analysis|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9381" PostTypeId="2" ParentId="4220" CreationDate="2017-01-01T15:49:37.347" Score="-2" Body="&lt;p&gt;It's called an ice spike. Not fully understood, can form on any surface of frozen water. my curiosity was peaked when one formed in a cup of water in my car. Scientists can't really say why it happens yet. &lt;/p&gt;&#xA;" OwnerUserId="7233" LastEditorUserId="725" LastEditDate="2017-01-04T09:50:20.727" LastActivityDate="2017-01-04T09:50:20.727" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9382" PostTypeId="2" ParentId="4868" CreationDate="2017-01-01T22:31:12.530" Score="0" Body="&lt;p&gt;The different schemes where to define grid-points has nothing to do with fidelity or easiness to handle.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The keyword here is a 'staggered grid'. In simulations of physics that compute conservation laws it makes sense to define scalar quantities (like density, temperature) at cell centers, while directed or vectorial quantities (momentum, energy flux) are defined at cell interfaces.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So depending which variable you're interested in looking at, the data for this variable can be shifted by 1/2 cell relative to the others. You have to take that into account when creating maps.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2017-01-01T22:31:12.530" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9383" PostTypeId="2" ParentId="6920" CreationDate="2017-01-01T23:50:19.283" Score="3" Body="&lt;p&gt;Cannot add to the excellent Time Zone, Daylight Savings, and Equation of Time (Mean Sun) explanations here, but I do want to mention something about the original question by Ian Paschal. It appears to be assumed that the high-point (culmination) and mid-point (transit) are the same, or that the point of highest altitude occurs on the celestial meridian. Though true for the stars, for other celestial bodies these are different. As D.A. Pio puts it in &lt;em&gt;Longitude from Moon Culminations&lt;/em&gt; (Royal Astronomical Society, Vol. 59, 1899; p. 513):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The author reminds the reader that only the fixed stars culminate really in the meridian. The Sun, the Moon, and all the planets culminate &lt;em&gt;out&lt;/em&gt; of the meridian.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Jürgen Giesen gives a mathematical analysis of it here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.geoastro.de/TransitCulm/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.geoastro.de/TransitCulm/index.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The difference is quite small for the sun, up to 18 seconds at mid-latitudes (I believe this is ignored in celestial navigation), but it can be more than 6 minutes in the case of the moon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also related (tangentially) to Paschal's question, back before time zones and widely-available accurate timepieces, there were specialized sundials called noon-marks whose sole purpose was to indicate the Local Apparent Noon (LAN).&lt;/p&gt;&#xA;" OwnerUserId="7234" LastActivityDate="2017-01-01T23:50:19.283" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9384" PostTypeId="1" AcceptedAnswerId="9415" CreationDate="2017-01-02T11:34:10.930" Score="2" ViewCount="7803" Body="&lt;p&gt;If rain is due to the flow of humid air from a high pressure area to a low pressure area, without the use of devices, technology or mass media is it possible to detect regions of high or low atmospheric pressure and know their locations?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example: from my terrace or open land - and how do I spot regions of low or high atmospheric pressure?&lt;/p&gt;&#xA;" OwnerUserId="7236" LastEditorUserId="2470" LastEditDate="2017-01-03T11:53:03.493" LastActivityDate="2020-02-20T23:54:37.383" Title="How to identify low or high pressure area" Tags="|wind|sea-level|rainfall|barometric-pressure|air-currents|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9385" PostTypeId="1" CreationDate="2017-01-02T18:36:21.057" Score="7" ViewCount="988" Body="&lt;p&gt;My task is to compute isentropic potential vorticity on a grid.&#xA;All data (ECMWF ens) are given on a hybrid sigma pressure grid.&#xA;Since I really cannot find reference, I assume (!) that relative vorticity (vo, id=138) is evaluated on model levels and therefore is useless for me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My approach (for each grid point):&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Compute theta-gradient, using the three model dimensions, converting vertical and horizontal distances to meters.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Define two vectors using three constraints each:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Scalar product with theta gradient vanishes.&lt;/li&gt;&#xA;&lt;li&gt;First vector has no meridional, second one no zonal component.&lt;/li&gt;&#xA;&lt;li&gt;Distance to adjacent horizontal grid point defines magnitude of &#xA;meridional/zonal component.&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;These two vectors now span a plane tangential to the isentropic surface at the current grid point. They point to positions only vertically displaced from the horizontal neighbours of the current grid point.&lt;/li&gt;&#xA;&lt;li&gt;Values of u and v are interpolated - again, using meters (geopotential height) - to the locations given by the tangent vectors.&lt;/li&gt;&#xA;&lt;li&gt;The geometrical length of these tangent vectors is determined and used together with the interpolated values of u and v to compute isentropic relative vorticity.&lt;/li&gt;&#xA;&lt;li&gt;Static stability is computed using values of pressure and theta at current point and vertical neighbour.&lt;/li&gt;&#xA;&lt;li&gt;Using gravitational acceleration and the conversion factor of 10^-6, I use the equation given in the famous book by Wallace &amp;amp; Hobbs for Potential Vorticity: $g(f + \eta_{\theta})\frac{\partial \theta}{\partial p}$&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;My problem:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The result does not look like what I expect.&#xA;Values range from around -30 to +50 pvu throughout the atmosphere, while the 1.5pvu surface clearly does not depict the tropopause. It looks more like an accident. I am using &quot;omp&quot; to increase computation speed, but things look the same if I don't use it, too, so it cannot be index confusion.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;My question:&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;What could be wrong?&#xA;Can you spot systematic errors? Maybe I got blind with time.&#xA;Do you know reference for how relative vorticity is evaluated in the ECMWF model? (I tried, really...)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To be more specific:&#xA;My method is to be implemented in C++ into an already existing environment to visualize NWP data in 3D in realtime.&#xA;The basic datafields - given in hybrid sigma coordinates - are read, processed, written into a derived data field, interpolated to and rendered on pressure levels as triggered by user interaction.&#xA;The program should possess the processing methods on its own, which is why I cannot use Python packages, for example.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is the source code of my approach.  If something is unclear, please ask!&#xA;Maybe somebody will spot an error.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt; // ISENTROPIC POTENTIAL VORTICITY&#xA;// Input grids : 0 t, 1 q, 2 u, 3 v, 4 sfcPhi, 5 sfc t_d, 6 sfc t, 7 sfc p, 8 sfc u, 9 sfc v&#xA;else if ( (derivedVarName == &quot;Isentropic PV (an)&quot;)&#xA;     || (derivedVarName == &quot;Isentropic PV (fc)&quot;)&#xA;     || (derivedVarName == &quot;Isentropic PV (ens)&quot;) )&#xA;{&#xA;    unsigned int k, j, i;&#xA;    int n, l;&#xA;#pragma omp parallel&#xA;        {&#xA;        #pragma omp for private(k, j, i, n, l)&#xA;    for (k = 1; k &amp;lt; derivedGrid-&amp;gt;getNumLevels() - 1; k++)&#xA;        for (j = 0; j &amp;lt; derivedGrid-&amp;gt;getNumLats() - 1; j++)&#xA;            for (i = 0; i &amp;lt; derivedGrid-&amp;gt;getNumLons() - 1; i++)&#xA;    {&#xA;&#xA;        // Current grid point.&#xA;        double T000 = inputGrids.at(0)-&amp;gt;getValue(k, j, i);&#xA;        double p000 = inputGrids.at(0)-&amp;gt;getPressure(k, j, i);&#xA;        double q000 = inputGrids.at(1)-&amp;gt;getValue(k, j, i);&#xA;        double theta000 = potTemp(T000, p000);&#xA;&#xA;        // Upper neighbour.&#xA;        double T100 = inputGrids.at(0)-&amp;gt;getValue(k-1, j, i);&#xA;        double p100 = inputGrids.at(0)-&amp;gt;getPressure(k-1, j, i);&#xA;        double q100 = inputGrids.at(1)-&amp;gt;getValue(k-1, j, i);&#xA;        double theta100 = potTemp(T100, p100);&#xA;&#xA;        // x-neighbour.&#xA;        double theta001 = potTemp(inputGrids.at(0)-&amp;gt;getValue(k, j, i+1),&#xA;                                  inputGrids.at(0)-&amp;gt;getPressure(k, j, i+1));&#xA;&#xA;        // y-neighbour.&#xA;        double theta010 = potTemp(inputGrids.at(0)-&amp;gt;getValue(k, j+1, i),&#xA;                                  inputGrids.at(0)-&amp;gt;getPressure(k, j+1, i));&#xA;&#xA;        // (1) Compute theta gradient at current point, using geopotential thickness dZ [m] for the vertical,&#xA;        // great circle distance [m] for the horizontal distances.&#xA;&#xA;            // Compute geopotential thickness between current point and upper neighbour.&#xA;            double T_v = (virtualTempFromSpecHum(T000, q000) + virtualTempFromSpecHum(T100, q100)) / 2.;&#xA;            double dPhi = geopotThickness(T_v, p100, p000);&#xA;            double dZ = geopotToZ(dPhi);&#xA;&#xA;            // Compute gradient.&#xA;            double* grad = gradient(theta000,&#xA;                                    inputGrids.at(0)-&amp;gt;getEastInterfaceLon(i),&#xA;                                    inputGrids.at(0)-&amp;gt;getNorthInterfaceLat(j), // Current grid point.&#xA;&#xA;                                    theta001,&#xA;                                    inputGrids.at(0)-&amp;gt;getEastInterfaceLon(i+1), // xlon-neighbour.&#xA;&#xA;                                    theta010,&#xA;                                    inputGrids.at(0)-&amp;gt;getNorthInterfaceLat(j+1), // ylat-neighbour.&#xA;&#xA;                                    theta100,&#xA;                                    dZ // Z-neighbour.&#xA;                                    );&#xA;&#xA;            // Gradient components.&#xA;            double xgrad = grad[2];&#xA;            double ygrad = grad[1];&#xA;            double Zgrad = grad[0];&#xA;&#xA;        // (2) Define tangent vectors and compute their Z-components.&#xA;        // Definition:&#xA;        // 1) Scalar product of tangent vectors with gradient vanishes.&#xA;        // 2) One tangent vector in y-z-plane, the other in x-z-plane.&#xA;        // 3) Length of horizontal components equals spacing between grid points.&#xA;        double radius_m = MetConstants::EARTH_RADIUS_km * 1000.;&#xA;&#xA;            // Tangent vector in y-z-plane.&#xA;            double dx = gcDistance_deg(inputGrids.at(0)-&amp;gt;getEastInterfaceLon(i),&#xA;                                       inputGrids.at(0)-&amp;gt;getNorthInterfaceLat(j),&#xA;                                       inputGrids.at(0)-&amp;gt;getEastInterfaceLon(i+1),&#xA;                                       inputGrids.at(0)-&amp;gt;getNorthInterfaceLat(j),&#xA;                                       radius_m);&#xA;&#xA;            // Z-component.&#xA;            double dZ_x = -dx * xgrad / Zgrad;&#xA;&#xA;            // Tangent vector in x-z-plane.&#xA;            double dy = gcDistance_deg(inputGrids.at(0)-&amp;gt;getEastInterfaceLon(i),&#xA;                                       inputGrids.at(0)-&amp;gt;getNorthInterfaceLat(j),&#xA;                                       inputGrids.at(0)-&amp;gt;getEastInterfaceLon(i),&#xA;                                       inputGrids.at(0)-&amp;gt;getNorthInterfaceLat(j+1),&#xA;                                       radius_m);&#xA;&#xA;            // Z-component.&#xA;            double dZ_y = -dy * ygrad / Zgrad;&#xA;&#xA;        // Tangent vectors now point from current grid point to locations only&#xA;        // vertically displaced from x- or y-neighbour, respectively.&#xA;&#xA;        // (3) Find levels whose Z values enclose geopotential height values and&#xA;        // interpolate u and v to these values.&#xA;        // The geopotential height of the current grid point is computed in the&#xA;        // x-coordinate section and reused in the y-coordinate section.&#xA;&#xA;                // x-coordinate&#xA;                double vdx; // Interpolated value of v.&#xA;                double Z_x; // Interpolation value of Z.&#xA;&#xA;                // (3a) Compute geopotential height of current grid point and add Z component&#xA;                // of x-Z-plane tangent vector.&#xA;                    // PV : 0 t, 1 q, 2 u, 3 v, 4 sfcPhi, 5 sfc t_d, 6 sfc t, 7 sfc p&#xA;&#xA;                    // Surface geopotential.&#xA;                    double geopotSurf_J = inputGrids.at(4)-&amp;gt;getValue(0, j, i);&#xA;&#xA;                    // Assuming temperature ranging from -45 to +60 degrees Celsius.&#xA;&#xA;                    // Raphido: Only sfc T_v is used. Use mean value instead, also in geopotential height method.&#xA;                    // Surface virtual temperature.&#xA;                    double pSurf_hPa = inputGrids.at(7)-&amp;gt;getValue(0, j, i) / 100.;&#xA;                    double virtualTempSurf_K = virtualTempFromDewPoint(inputGrids.at(5)-&amp;gt;getValue(0, j, i),&#xA;                                                                       pSurf_hPa,&#xA;                                                                       inputGrids.at(6)-&amp;gt;getValue(0, j, i));&#xA;&#xA;                    // Surface layer geopotential thickness.&#xA;                    double dPhiSurfLayer = geopotThickness(virtualTempSurf_K,&#xA;                                                           inputGrids.at(0)-&amp;gt;getPressure(inputGrids.at(0)-&amp;gt;getNumLevels() - 1, j, i),&#xA;                                                           pSurf_hPa);&#xA;&#xA;                    double geopotential000_J = 0.;&#xA;&#xA;                    double virtualTemp_av_K = 0.;&#xA;                    double dPhi_J = 0.;&#xA;&#xA;                    // For each point, loop from surface pressure level to current pressure level (k).&#xA;                    for (l = derivedGrid-&amp;gt;getNumLevels() - 2; l &amp;gt; k-1; l--)&#xA;                    {&#xA;&#xA;                        // Compute average virtual temperature between current pressure level&#xA;                        // and lower level.&#xA;                        virtualTemp_av_K = ( virtualTempFromSpecHum(inputGrids.at(0)-&amp;gt;getValue(l, j, i),&#xA;                                                                    inputGrids.at(1)-&amp;gt;getValue(l, j, i))&#xA;                                           + virtualTempFromSpecHum(inputGrids.at(0)-&amp;gt;getValue(l+1, j, i),&#xA;                                                                    inputGrids.at(1)-&amp;gt;getValue(l+1, j, i)) ) / 2.;&#xA;&#xA;                        // Compute the current thickness.&#xA;                        dPhi_J = geopotThickness(virtualTemp_av_K,&#xA;                                                 inputGrids.at(0)-&amp;gt;getPressure(l, j, i),&#xA;                                                 inputGrids.at(0)-&amp;gt;getPressure(l+1, j, i));&#xA;&#xA;                        // Sum up the differentials.&#xA;                        geopotential000_J += dPhi_J;&#xA;                    }&#xA;&#xA;                    // Add surface layer geopotential thickness&#xA;                    geopotential000_J += dPhiSurfLayer;&#xA;&#xA;                    // Add surface geopotential&#xA;                    geopotential000_J += geopotSurf_J;&#xA;&#xA;                    // Convert to geopotential height by dividing through g_0.&#xA;                    Z_x = geopotToZ(geopotential000_J);&#xA;&#xA;                    // Add gradient contribution.&#xA;                    Z_x += dZ_x;&#xA;&#xA;                // (3b) Loop through model levels to find adjacent grid points enclosing Z_x.&#xA;                // Starting from the lowermost level, compute geopotential height of adjacent grid points.&#xA;                for(n = derivedGrid-&amp;gt;getNumLevels() - 1; n &amp;gt; 1; n--)&#xA;                {&#xA;&#xA;                        // Surface geopotential.&#xA;                        double geopotSurf_J = inputGrids.at(4)-&amp;gt;getValue(0, j, i+1);&#xA;&#xA;                        // Assuming temperature ranging from -45 to +60 degrees Celsius&#xA;&#xA;                        // Surface virtual temperature.&#xA;                        double pSurf_hPa = inputGrids.at(7)-&amp;gt;getValue(0, j, i+1) / 100.;&#xA;                        double virtualTempSurf_K = virtualTempFromDewPoint(inputGrids.at(5)-&amp;gt;getValue(0, j, i+1),&#xA;                                                                          pSurf_hPa,&#xA;                                                                          inputGrids.at(6)-&amp;gt;getValue(0, j, i+1));&#xA;&#xA;                        // Surface layer geopotential thickness&#xA;                        double dPhiSurfLayer = geopotThickness(virtualTempSurf_K,&#xA;                                                              inputGrids.at(0)-&amp;gt;getPressure(inputGrids.at(0)-&amp;gt;getNumLevels() - 1, j, i+1),&#xA;                                                              pSurf_hPa);&#xA;&#xA;                        // Lower neighbour.&#xA;                        double geopotential_J_lower = geopotSurf_J;&#xA;                        double Zx_bot = geopotToZ(geopotential_J_lower);&#xA;&#xA;                        // Upper neighbour.&#xA;                        double geopotential_J_upper = geopotential_J_lower + dPhiSurfLayer;&#xA;                        double Zx_top = geopotToZ(geopotential_J_upper);&#xA;&#xA;                        // Check whether adjacent grid points enclose Z_x.&#xA;                        // If they do, check whether surface is involved or not, then interpolate.&#xA;                        if((Zx_bot &amp;lt; Z_x) &amp;amp;&amp;amp; (Z_x &amp;lt; Zx_top))&#xA;                        {&#xA;&#xA;                            // Surface level involved.&#xA;                            if(n == derivedGrid-&amp;gt;getNumLevels() - 1)&#xA;                            {&#xA;                                double v_top = inputGrids.at(3)-&amp;gt;getValue(inputGrids.at(0)-&amp;gt;getNumLevels() - 1, j, i+1);&#xA;                                double v_bot = inputGrids.at(9)-&amp;gt;getValue(0, j, i+1);&#xA;&#xA;                                // Interpolated value of v.&#xA;                                vdx = v_bot + (v_top - v_bot) * (Z_x - Zx_bot) / (Zx_top - Zx_bot);&#xA;&#xA;                                break;&#xA;                            }&#xA;&#xA;                            // Surface level not involved.&#xA;                            else&#xA;                            {&#xA;                                double v_top = inputGrids.at(3)-&amp;gt;getValue(n-1, j, i+1);&#xA;                                double v_bot = inputGrids.at(3)-&amp;gt;getValue(n, j, i+1);&#xA;&#xA;                                // Interpolated value of v.&#xA;                                vdx = v_bot + (v_top - v_bot) * (Z_x - Zx_bot) / (Zx_top - Zx_bot);&#xA;&#xA;                                break;&#xA;                            }&#xA;&#xA;                        }&#xA;                        // Z_x not enclosed, go one level up.&#xA;                        else&#xA;                        {&#xA;                            geopotential_J_lower = geopotential_J_upper;&#xA;                            Zx_bot = geopotToZ(geopotential_J_lower);&#xA;&#xA;                            double virtualTemp_av_K = 0.;&#xA;                            double dPhi_J = 0.;&#xA;&#xA;&#xA;&#xA;                            // Compute average virtual temperature between current pressure level&#xA;                            // and lower level.&#xA;                            virtualTemp_av_K = ( virtualTempFromSpecHum(inputGrids.at(0)-&amp;gt;getValue(n, j, i+1),&#xA;                                                                        inputGrids.at(1)-&amp;gt;getValue(n, j, i+1))&#xA;                                               + virtualTempFromSpecHum(inputGrids.at(0)-&amp;gt;getValue(n-1, j, i+1),&#xA;                                                                        inputGrids.at(1)-&amp;gt;getValue(n-1, j, i+1)) ) / 2.;&#xA;&#xA;                            // Compute the current thickness.&#xA;                            dPhi_J = geopotThickness(virtualTemp_av_K,&#xA;                                                     inputGrids.at(0)-&amp;gt;getPressure(n-1, j, i+1),&#xA;                                                     inputGrids.at(0)-&amp;gt;getPressure(n, j, i+1));&#xA;&#xA;&#xA;                            geopotential_J_upper += dPhi_J;&#xA;                            Zx_top = geopotToZ(geopotential_J_upper);&#xA;                        }&#xA;&#xA;                }&#xA;&#xA;                // y-coordinate&#xA;                double udy; // Interpolated value of u.&#xA;                double Z_y; // Interpolation value of Z.&#xA;&#xA;                // (3c) Compute geopotential height of current grid point and add Z component&#xA;                // of y-Z-plane tangent vector&#xA;&#xA;                    // Geopotential at current grid point already known.&#xA;                    // Convert to geopotential height.&#xA;                    Z_y = geopotToZ(geopotential000_J);&#xA;&#xA;                    // Add gradient contribution.&#xA;                    Z_y += dZ_y;&#xA;&#xA;                // (3d) Loop through model levels to find adjacent grid points enclosing Z_y.&#xA;                // Starting from the lowermost level, compute geopotential height of adjacent grid points.&#xA;                for(n = derivedGrid-&amp;gt;getNumLevels() - 1; n &amp;gt; 1; n--)&#xA;                {&#xA;&#xA;                        // Surface geopotential.&#xA;                        double geopotSurf_J = inputGrids.at(4)-&amp;gt;getValue(0, j+1, i);&#xA;&#xA;                        // Assuming temperature ranging from -45 to +60 degrees Celsius.&#xA;&#xA;                        // Surface virtual temperature.&#xA;                        double pSurf_hPa = inputGrids.at(7)-&amp;gt;getValue(0, j+1, i) / 100.;&#xA;                        double virtualTempSurf_K = virtualTempFromDewPoint(inputGrids.at(5)-&amp;gt;getValue(0, j+1, i),&#xA;                                                                           pSurf_hPa,&#xA;                                                                           inputGrids.at(6)-&amp;gt;getValue(0, j+1, i));&#xA;&#xA;                        // Surface layer geopotential thickness&#xA;                        double dPhiSurfLayer = geopotThickness(virtualTempSurf_K,&#xA;                                                               inputGrids.at(0)-&amp;gt;getPressure(inputGrids.at(0)-&amp;gt;getNumLevels() - 1, j+1, i),&#xA;                                                               pSurf_hPa);&#xA;&#xA;                        // Lower neighbour.&#xA;                        double geopotential_J_lower = geopotSurf_J;&#xA;                        double Zy_bot = geopotToZ(geopotential_J_lower);&#xA;&#xA;                        // Upper neighbour.&#xA;                        double geopotential_J_upper = geopotential_J_lower + dPhiSurfLayer;&#xA;                        double Zy_top = geopotToZ(geopotential_J_upper);&#xA;&#xA;                        // Check whether adjacent grid points enclose Z_x.&#xA;                        // If they do, check whether surface is involved or not, then interpolate.&#xA;                        if((Zy_bot &amp;lt; Z_y) &amp;amp;&amp;amp; (Z_y &amp;lt; Zy_top))&#xA;                        {&#xA;&#xA;                            // Surface level involved.&#xA;                            if(n == derivedGrid-&amp;gt;getNumLevels() - 1)&#xA;                            {&#xA;                                double u_top = inputGrids.at(2)-&amp;gt;getValue(inputGrids.at(0)-&amp;gt;getNumLevels() - 1, j+1, i);&#xA;                                double u_bot = inputGrids.at(8)-&amp;gt;getValue(0, j+1, i);&#xA;&#xA;                                // Interpolated value of v.&#xA;                                udy = u_bot + (u_top - u_bot) * (Z_y - Zy_bot) / (Zy_top - Zy_bot);&#xA;&#xA;                                break;&#xA;                            }&#xA;&#xA;                            // Surface level not involved.&#xA;                            else&#xA;                            {&#xA;                                double u_top = inputGrids.at(2)-&amp;gt;getValue(n-1, j+1, i);&#xA;                                double u_bot = inputGrids.at(2)-&amp;gt;getValue(n, j+1, i);&#xA;&#xA;                                // Interpolated value of u.&#xA;                                udy = u_bot + (u_top - u_bot) * (Z_y - Zy_bot) / (Zy_top - Zy_bot);&#xA;&#xA;                                break;&#xA;                            }&#xA;&#xA;                        }&#xA;                        // Z_y not enclosed, go one level up.&#xA;                        else&#xA;                        {&#xA;                            geopotential_J_lower = geopotential_J_upper;&#xA;                            Zy_bot = geopotToZ(geopotential_J_lower);&#xA;&#xA;                            double virtualTemp_av_K = 0.;&#xA;                            double dPhi_J = 0.;&#xA;&#xA;&#xA;&#xA;                            // Compute average virtual temperature between current pressure level&#xA;                            // and lower level.&#xA;                            virtualTemp_av_K = ( virtualTempFromSpecHum(inputGrids.at(0)-&amp;gt;getValue(n, j+1, i),&#xA;                                                                        inputGrids.at(1)-&amp;gt;getValue(n, j+1, i))&#xA;                                               + virtualTempFromSpecHum(inputGrids.at(0)-&amp;gt;getValue(n-1, j+1, i),&#xA;                                                                        inputGrids.at(1)-&amp;gt;getValue(n-1, j+1, i)) ) / 2.;&#xA;&#xA;                            // Compute the current thickness.&#xA;                            dPhi_J = geopotThickness(virtualTemp_av_K,&#xA;                                                     inputGrids.at(0)-&amp;gt;getPressure(n-1, j+1, i),&#xA;                                                     inputGrids.at(0)-&amp;gt;getPressure(n, j+1, i));&#xA;&#xA;&#xA;                            geopotential_J_upper += dPhi_J;&#xA;                            Zy_top = geopotToZ(geopotential_J_upper);&#xA;                        }&#xA;&#xA;                }&#xA;&#xA;        // OLD: Compute geometrical length of tangent vectors.&#xA;        // NEW: Write new method using the already computed dZ's.&#xA;        double dx_Z = vecLengthZ(dx, 0, dZ_x);&#xA;&#xA;        double dy_Z = vecLengthZ(0, dy, dZ_y);&#xA;&#xA;        // Compute wind differences&#xA;        double du = udy - inputGrids.at(2)-&amp;gt;getValue(k, j, i);&#xA;        double dv = vdx - inputGrids.at(3)-&amp;gt;getValue(k, j, i);&#xA;&#xA;        // Compute isentropic relative vorticity.&#xA;        double vo_rel = (du / dy_Z) - (dv / dx_Z);&#xA;&#xA;        // Compute static stability.&#xA;        double dTheta = theta100 - theta000;&#xA;        double dp = 100. * (p100 - p000);&#xA;&#xA;        // Compute planetary vorticity.&#xA;        // vo_plan = 2. * w_0 * sin(2. * M_PI * lat / 360.);&#xA;        double w_0 = MetConstants::EARTH_ROTATION_RATE;&#xA;        double lat000 = inputGrids.at(0)-&amp;gt;getNorthInterfaceLat(j);&#xA;        double vo_plan = 2. * w_0 * sin(2. * M_PI * lat000 / 360.);&#xA;&#xA;        // Compute PV[pvu]&#xA;        double factor = MetConstants::PVU_FACTOR;&#xA;        double g = MetConstants::GRAVITY_ACCELERATION;&#xA;        double PV_pvu = factor * g * (vo_rel + vo_plan) * (dTheta / dp);&#xA;&#xA;        derivedGrid-&amp;gt;setValue(k, j, i, PV_pvu);&#xA;    }&#xA;    }&#xA;&#xA;}&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="7237" LastEditorDisplayName="user1161" LastEditDate="2017-06-12T22:52:13.860" LastActivityDate="2019-01-26T08:05:19.113" Title="Computing Isentropic Potential Vorticity from Hybrid Sigma Pressure levels" Tags="|meteorology|numerical-modelling|data-analysis|vorticity|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="9386" PostTypeId="2" ParentId="7425" CreationDate="2017-01-03T01:50:14.020" Score="2" Body="&lt;p&gt;The 'natural causes' of global methane emissions are, as you indicate, mostly of biological origin. To some extent it depends upon what you regard as 'natural'. There are many and differing estimates of global methane generation, of which I list a summary below. Those in bold you may regard as abiological. Values are in Mega-tonnes per year released to the atmosphere:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wetlands 217&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fossil Fuels 96&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ruminants 89&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Landfill 75&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Geological sources 54&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Freshwater 40&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Biofuels 38&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rice growing 36&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Oceans - DMS  20&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Termites 11&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Wildfires 10&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's a moot point as to whether degradation of dimethyl sulphide (DMS) is biological or not. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2017-01-03T01:50:14.020" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9387" PostTypeId="1" CreationDate="2017-01-03T03:20:14.633" Score="7" ViewCount="173" Body="&lt;p&gt;I don't doubt that K-Ar dating of rocks is a sound method, but in discussions with skeptics it would be good to know just how reliable exactly? For example, has K-Ar been cross-checked with other rock dating methods, such as radiocarbon, sediment varves, etc. If so, yielding what level of correlation?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="1411" LastEditDate="2017-01-09T15:00:42.687" LastActivityDate="2017-01-10T17:40:10.453" Title="How good is K-Ar dating?" Tags="|dating|isotopic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9388" PostTypeId="2" ParentId="9379" CreationDate="2017-01-03T03:48:52.067" Score="2" Body="&lt;p&gt;An intrinsic assumption in using geostatistics is that one can approximate a distribution by a polynomial surface. In practice, maybe you can do this in a very simple geological situation, such as an isotropic shockwave arising from sedimentary compaction in horizontal sediments. When it comes to major seismic events at tectonic plate edges I think the seismic energy distribution might be too complex. For example, the seismic energy is attenuated at different rates on either side of a subduction zone, and tends to be channeled along the ocean floor according to local bathymetry and structure (especially along mid-ocean ridges). Also, the shock wave distribution will be different according to whether the source is shallow or deep. Trying to account for such features in a geostatistical model will be a nightmare of complexity - good luck!&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2017-01-03T03:48:52.067" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9389" PostTypeId="1" CreationDate="2017-01-03T02:51:23.237" Score="5" ViewCount="170" Body="&lt;p&gt;So why are snow thunderstorms so rare? I researched a bit and it said that it is because there is less moisture in the air. But the &lt;em&gt;percentage&lt;/em&gt; of thunderstorms while raining seems much higher than the the percentage of thunderstorms while snowing. Less moisture would only prove why there are less snowstorms correct?&lt;/p&gt;&#xA;" OwnerUserId="7242" OwnerDisplayName="Clangorous Chimera" LastEditorUserId="477" LastEditDate="2017-01-23T09:16:27.197" LastActivityDate="2017-01-23T20:50:25.960" Title="Snow thunderstorms" Tags="|temperature|snow|storms|thunderstorm|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9392" PostTypeId="2" ParentId="9097" CreationDate="2017-01-03T17:25:10.270" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/9098/1399&quot;&gt;Gordon Stanger's answer&lt;/a&gt; has already made perhaps the main point: There's absolutely no reason to believe that the evolution of a planet in one part of the Solar System should exactly mirror that of any other planet. We see drastic composition and size differences among the terrestrial planets; why should any other properties be similar?&lt;/p&gt;&#xA;&lt;p&gt;I'm aware of several possible mechanisms that explain why Venus spins so slowly.&lt;/p&gt;&#xA;&lt;h3&gt;Repeated impacts and the formation (and death) of a moon&lt;/h3&gt;&#xA;&lt;p&gt;Venus has no moon - a curious fact, considering that the only other planet to not have one is Mercury. You could ascribe this to many factors, such as relatively low masses and close proximity to the Sun. However, some models have suggested that there &lt;em&gt;was&lt;/em&gt; a moon around Venus, which is now gone.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://adsabs.harvard.edu/abs/2006DPS....38.0703A&quot; rel=&quot;nofollow noreferrer&quot;&gt;Alemi &amp;amp; Stevenson (2006)&lt;/a&gt; proposed a complicated story of impacts. Their model suggests that Venus suffered a &lt;a href=&quot;https://en.wikipedia.org/wiki/Giant_impact_hypothesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;giant impact&lt;/a&gt; from a moderately sized protoplanet. As was the case with Earth, debris was thrown up, and a moon coalesced in orbit. This changed Venus' rotation, and began to transfer even more angular momentum to the moon. However, a &lt;em&gt;second&lt;/em&gt; impact to Venus reversed its rotation, and the moon fell back to the planet, transferring its angular momentum back. This would all happen on the order of ten million years or so, starting and possibly ending during the &lt;a href=&quot;https://en.wikipedia.org/wiki/Late_Heavy_Bombardment&quot; rel=&quot;nofollow noreferrer&quot;&gt;Late Heavy Bombardment&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The upshot of all this is that Venus emerged with not just a retrograde rotation, but a much longer day. This is, of course, not the sole explanation for the retrograde rotation - exotic scenarios involving 180 degree flips have been proposed; see e.g. &lt;a href=&quot;http://www.nature.com/nature/journal/v411/n6839/abs/411767a0.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Correia &amp;amp; Laskar (2001)&lt;/a&gt; - but the impact hypothesis does have the added advantage of explaining the lack of a moon.&lt;/p&gt;&#xA;&lt;h3&gt;Atmospheric tides and internal friction&lt;/h3&gt;&#xA;&lt;p&gt;Interactions with the Sun have also been proposed as a mechanism affecting not just Venus, but exoplanets like it. &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_tide&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atmospheric tides&lt;/a&gt;, generated through heating and cooling from the Sun, could enact a torque on the planet, bringing it into one of several &amp;quot;equilibrium states&amp;quot; (see &lt;a href=&quot;https://arxiv.org/abs/1611.05678&quot; rel=&quot;nofollow noreferrer&quot;&gt;Auclair-Desrotour et al. (2016)&lt;/a&gt;). Internal friction could cause more complex interactions in the mantle, further exaggerating the effects on the solid part of the planet. The same thing could happen to any planet orbiting the Sun at roughly the same distance as Venus in the Solar System.&lt;/p&gt;&#xA;&lt;p&gt;It was once proposed that an additional torque was applied to Venus by Earth, complementing the solar atmospheric tides, as there appears to be a coupling between the time between close approaches to Earth and the time of one Venusian day. However, it has since been determined that such a resonance does not, in fact, exist, and should be discounted as a possible reason for the slowing of Venus's rotation (see &lt;a href=&quot;http://adsabs.harvard.edu/abs/1979ApJ...230L.123S&quot; rel=&quot;nofollow noreferrer&quot;&gt;Shapiro et al. (1979)&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;h3&gt;Why not Earth?&lt;/h3&gt;&#xA;&lt;p&gt;So, why would these effects happen to Venus but not Earth? The chaos of the early Solar System is of course the best answer, but there are other explanations for the specific proposals. The impact theory simply relies on randomness: While Venus and Earth were both likely to suffer major moon-forming collisions, they were not as likely to go through this &lt;em&gt;twice&lt;/em&gt;. The atmospheric tidal effects, on the other hand, could have been unavoidable, as interactions with the Sun may have been more severe with Venus, for a variety of reasons including distance to the Sun and the exact properties of the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="1399" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-01-03T22:05:08.367" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9393" PostTypeId="1" CreationDate="2017-01-04T01:11:48.813" Score="4" ViewCount="86" Body="&lt;p&gt;I realize that this question may be arguably off-topic, but there doesn't seem to be a stack exchange specific to oceanography, geography, or architecture. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With rising sea level in mind, how high above sea level are the front doors of 'at risk' iconic structures, such as the One World Trade Center in New York, the Opera House in Sydney, and the Shanghai Tower? If it is true that sea level will ultimately rise not less than six metres (albeit not for several centuries hence), then will these buildings all become islands? &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="111" LastEditDate="2017-01-04T03:10:46.423" LastActivityDate="2017-01-04T03:10:46.423" Title="Rising sea level: flooding of iconic buildings" Tags="|oceanography|geography|sea-level|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9394" PostTypeId="1" CreationDate="2017-01-04T05:50:31.377" Score="6" ViewCount="254" Body="&lt;h3&gt;Background&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Eastern China now (2017.01) are suffering severe haze with striking concentration of PM2.5.&lt;br&gt;&#xA;Haze, with low visibility and complex chemical components threatens billions of persons' health.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But when I look through the pollutants concentration all over the country, I found some phenomenon interesting.  &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;General&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Here is a snapshot of PM2.5 concentration distribution map of eastern china (clipped from aqistudy.cn).        &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The circle with red and purple color represent the high ground-level loading of PM2.5.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZBfmx.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZBfmx.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;From the figure above, we can identify the locations with high PM2.5 conc.   &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Meanwhile, I also clipped the O3 concentration distribution at the same time.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/l3Jnk.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/l3Jnk.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;From the figure above, we can observe that O3 pollution are not severe in haze zone.&lt;br&gt;&#xA;  Actually, the conc of Ozone are lower in the area which the PM2.5 conc are higher.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The real-time data are also presented here a supplement. I choose Beijing, Xi'an (two large city in China), Zhoushan(an island in Eastern China Sea), Sanya(nearby the southern China Sea) &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;City     | PM2.5 |   NO2  | SO2  | O3&#xA;-------------------------------------&#xA;Beijing  |  229  |  109   |  30  |  7  &#xA;Xi'an    |  381  |  147   |  34  |  12 &#xA;Zhoushan |  20   |  28    |  14  |  70 &#xA;Sanya    |  16   |   9    |   2  |  77  &#xA;&#xA; ###  units: ug/m3&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;IMHO, the high conc of PM2.5 and low conc of O3 can be explained as follows: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;High loading of Aerosol -&gt; strong extinction effect -&gt; week solar radiation -&gt; O3 formation slow down &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Here is another figure I clipped from Cheng et al. Sci. Adv. 2016. It depicts the NO2 and O3 conc in different PM2.5 level.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4Y3IW.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4Y3IW.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;h3&gt;An Special case&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Look at the city of Anqing (30.5319° N, 117.1151° E), its PM2.5 and O3 concentration has a strange phenomenon. I clipped some figure of its air quality status (2016-01-04 local 12:00:00)  &lt;/p&gt;&#xA;&#xA;Fig 1 Anqing City and Chizhou City&#xA;&#xA;&lt;p&gt;These two nearby cities are in the distance less than 60 Km, has the similar PM2.5 conc with different O3 conc&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3jl7m.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3jl7m.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;Fig 2 Anqing City and its surrounding area&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AZlPg.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AZlPg.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What attract me is the high conc O3 of Anqing City comparing with its nearby area. And I found this feature is rare in China.  &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Anyone has some theory to explain that? Any discussion or advises would be great!&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="6031" LastEditDate="2019-04-21T05:29:52.823" LastActivityDate="2019-04-21T05:29:52.823" Title="How to understand the bizarre high level for both PM2.5 and Ozone" Tags="|atmospheric-chemistry|air-pollution|ozone|air-quality|pm2.5|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9395" PostTypeId="1" CreationDate="2017-01-04T17:44:06.113" Score="7" ViewCount="302" Body="&lt;p&gt;J. Marvin Herndon claims that the evidence of the georeactor comes from &lt;sup&gt;3&lt;/sup&gt;He/&lt;sup&gt;4&lt;/sup&gt;He ratios released to the oceans at the mid oceanic ridges. Georeactor-produced &lt;sup&gt;3&lt;/sup&gt;He/&lt;sup&gt;4&lt;/sup&gt;He ratios are related to the extent of actinide fuel consumption at time of production and are high near the end of the georeactor lifetime. Georeactor numerical simulation results and the observed high &lt;sup&gt;3&lt;/sup&gt;He/&lt;sup&gt;4&lt;/sup&gt;He ratios measured in Icelandic and Hawaiian oceanic basalts indicate that the demise of the georeactor is approaching. Is Herndon correct in claiming that the &lt;sup&gt;3&lt;/sup&gt;He and &lt;sup&gt;4&lt;/sup&gt;He in oceanic basalt are being produced by a georeactor in the Earth's core? If not, what is their origin?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reference:&lt;br /&gt;&#xA;&lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC152243/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nuclear georeactor origin of oceanic basalt &lt;sup&gt;3&lt;/sup&gt;He/&lt;sup&gt;4&lt;/sup&gt;He, evidence, and implications&lt;/a&gt; (or as &lt;a href=&quot;http://www.nucleonica.net/wiki/images/a/a5/Herndon_2003.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;PDF&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="7210" LastEditorUserId="94" LastEditDate="2017-01-06T11:54:42.367" LastActivityDate="2017-01-07T10:51:31.670" Title="Are Helium 3 and 4 being produced by earth's core?" Tags="|core|geomagnetism|radioactivity|ocean-ridge|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9396" PostTypeId="2" ParentId="9394" CreationDate="2017-01-04T19:04:17.393" Score="6" Body="&lt;p&gt;I think it is important to keep in mind the mechanisms that form PM$_{2.5}$ are different than the mechanisms that form O$_3$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the data your provided you can draw some simple conclusions:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Increasing SO$_2$ increases PM$_{2.5}$&lt;/li&gt;&#xA;&lt;li&gt;Increasing NO$_2$ increases PM$_{2.5}$&lt;/li&gt;&#xA;&lt;li&gt;Increasing NO$_2$ doesn't necessarily increase O$_{3}$&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The last point is what you seem to be struggling with. I think what you see here is 'the weekend effect' where lowering the NO$_2$ concentration increases O$_3$ concentration. In this effect, the generation of nitric acid and the destruction of O$_3$ by NO ($\ce{O_3 + NO → O_2 + NO_2}$) decreases the ozone, but increases NO$_2$. I think this explains the phenomenon seen.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="725" LastEditDate="2017-01-05T02:18:45.863" LastActivityDate="2017-01-05T02:18:45.863" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9398" PostTypeId="1" CreationDate="2017-01-04T23:02:36.250" Score="3" ViewCount="53" Body="&lt;p&gt;What storm tracks are favorable for snow in the eastern United States? Articles like &lt;a href=&quot;http://www.accuweather.com/en/weather-news/upcoming-major-winter-storm-in-1/44817&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one on a winter storm in the Northeast in 2011&lt;/a&gt; indicate that storm tracks are important in snowfall amounts. But other winter storm tracks seem to produce more maritime tropical weather. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know the heaviest snow usually falls to the west of the storm track where the cold air is located, but why do some storm tracks not produce any snow at all?  What influences the storm tracks that causes them to be prolific sometimes and duds other times?&lt;/p&gt;&#xA;" OwnerUserId="7249" LastEditorUserId="6298" LastEditDate="2017-01-10T22:18:10.267" LastActivityDate="2017-01-11T04:09:45.287" Title="What kind of storm tracks produce snow in the eastern United States?" Tags="|meteorology|weather-forecasting|storms|snow|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9403" PostTypeId="1" CreationDate="2017-01-05T16:41:22.077" Score="2" ViewCount="479" Body="&lt;p&gt;I have a seismic dataset that contains a depth-migrated seismic (amplitude) volume in depth and then the exact same volume converted to time using the migration velocities. Unfortunately, I do not have the velocity volume used to do the conversion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can I extract the velocity volume using only these two (amplitude) volumes?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the signals are exactly the same, just stretched and squeezed, I believe the solution will require something like &lt;a href=&quot;https://en.wikipedia.org/wiki/Dynamic_time_warping&quot; rel=&quot;nofollow noreferrer&quot;&gt;dynamic time warping&lt;/a&gt; but I don't have enough experience with this to make it work.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since each trace in the volume is converted independently, this reduces to a 1D problem. An optimal solution for a single trace can be used to solve the entire 3D volume (unless there is a lot of error and then we can have lateral instability, but I can live with that).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will eventually need to code it in MATLAB for application on sgy-formatted data.&lt;/p&gt;&#xA;" OwnerUserId="4636" LastActivityDate="2017-01-18T17:16:05.187" Title="Velocity from time and depth seismic images" Tags="|seismic|matlab|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9406" PostTypeId="1" CreationDate="2017-01-05T19:28:00.683" Score="7" ViewCount="2416" Body="&lt;p&gt;I am wondering if it is possible at all to calculate the ground temperature and air temperature at 10m above ground from 2m measurements, or at least using data that a standard weather station provides.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am aware it is an oversimplification, but I cannot seem to find any resources concerning the matter. Any help would be greatly appreciated!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit 2017/01/11:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you for your comments, so here is the reason why we are interested in this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We have noticed that there are often large differences in air temperature between 2m and 10m height, often of 4° to 5°C. I wanted to know if anyone else was interested in this, or are there any models out there which can be used to calculate temperatures at different heights, so a comparison between modelled and real values can be made.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is this interesting at all?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It would be great to have a way to know if in a certain area the temperature will not go below 0°C if we have measurements of temperature, humidity and wind at 2m. But, I presume in these days of cheap temperatures sensors and Arduinos, one can always stick a sensor anywere...&lt;/p&gt;&#xA;" OwnerUserId="7255" LastEditorUserId="321" LastEditDate="2019-10-03T04:02:44.457" LastActivityDate="2019-10-03T04:02:44.457" Title="Is there a way to calculate the ground and 10m temperature from standard 2m temperature measurements?" Tags="|meteorology|atmosphere|temperature|measurements|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="9407" PostTypeId="1" CreationDate="2017-01-05T20:40:28.927" Score="6" ViewCount="106" Body="&lt;p&gt;I have temperature data from a weather station, but there are missing data (not more than 80% of the daily temperature observations). The World Meteorological Organization has some rules to validate estimations of monthly temperatures, etc. (for example to have 80% of the data). But since my periods of time are related to the lifecycle of the migratory species I am studying, for example:&#xA;1) arrival to the breeding ground and egg laying is from 20-May to 20-Jun (31 days)&#xA;2) incubation is from 21-Jun to 15 July (24 days)&#xA;3) brood rearing is from 16-July to 15-Aug (30 days)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do you know if there are some other rules? for example when my period of time is &amp;lt;30 days? Does the same rule would apply for the incubation period, even if it is shorter than one month? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;thanks a lot for your advice/suggestions&lt;/p&gt;&#xA;" OwnerUserId="7256" LastEditorUserId="7256" LastEditDate="2017-01-05T21:12:00.600" LastActivityDate="2017-01-05T21:12:00.600" Title="Are there rules to estimate average temperature" Tags="|meteorology|temperature|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9410" PostTypeId="2" ParentId="8332" CreationDate="2017-01-05T23:37:33.377" Score="2" Body="&lt;p&gt;From NOAA: (Official US Science) A recent estimate for the average depth of the ocean is 3,682 meters, or 12,080 feet.&#xA;This is an estimate from 2010. Older estimates have deeper average ocean.&lt;/p&gt;&#xA;" OwnerUserId="7259" LastActivityDate="2017-01-05T23:37:33.377" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9412" PostTypeId="1" CreationDate="2017-01-05T23:58:49.073" Score="4" ViewCount="445" Body="&lt;p&gt;If we judge a hierarchy of a landmass by size, here is what, in my knowledge, it would have looked like, from largest to smallest:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Continent&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Subcontinent&lt;/p&gt;&#xA;&#xA;&lt;p&gt;???&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Island&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Islet&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In regards to size, is there a transition of landmasses between (sub)continent and island?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastEditorUserId="94" LastEditDate="2017-01-06T07:51:41.693" LastActivityDate="2017-01-07T16:58:48.847" Title="The Size Hierarchy of a Landmass" Tags="|geography|terminology|land|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9415" PostTypeId="2" ParentId="9384" CreationDate="2017-01-07T09:54:55.843" Score="4" Body="&lt;p&gt;Because you specifically asked about winds and pressure, there is a fairly applicable rule of thumb.  It's called &lt;strong&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Buys_Ballot&amp;#39;s_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Buys Ballot's Law&lt;/a&gt;&lt;/strong&gt;.  Basically, if the wind is to your back (coming behind you), and you're in the Northern Hemisphere, generally low pressure is to your left and high pressure is to your right.  This graphic from &lt;a href=&quot;http://www.maiamarinelli.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.maiamarinelli.com/&lt;/a&gt; illustrates it:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GdAky.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GdAky.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, do note that Buys Ballot is really an imperfect estimation.  There's three big caveats/adjustments to consider:&lt;br&gt;&#xA;&lt;em&gt;[in all following description, replace left with right (and vice versa) for Southern Hemisphere]&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The Buys Ballot Relationship fundamentally relies upon the Earth's rotation, i.e. the always vaunted apparent force termed the &lt;a href=&quot;http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/crls.rxml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Coriolis Effect&lt;/a&gt;.  Coriolis actually causes wind NOT to flow towards low pressure, but instead along equal pressure contours.  If it weren't for the Coriolis Effect, low pressure centers would quickly fill in with air, and we wouldn't have the complex weather that we have.  That said, at the equator, where the differences in rotation with latitude are smallest, Buys Ballot no longer works as there's limited/no Coriolis.  So the nearer the equator you are, the more low pressure would be more infront left, or even straight in front of you if wind is to your back.&lt;/li&gt;&#xA;&lt;li&gt;Friction also slightly imbalances the relationship near the ground, such that wind actually flows towards low pressure again.  So once again, wind to your back may actually indicate the low pressure center is more to your front left than your left at ground level.  If you were up off the ground, or out in a body of water, this friction adjustment would be minimized, and low pressure is indeed more to your left. &lt;/li&gt;&#xA;&lt;li&gt;Local effects, such as terrain (or buildings) definitely overwhelm the larger pattern at times.  And because the Coriolis force isn't significant in smaller, more localized features, Buys Ballot's becomes shakier in those situations.  The impetus from the broader wind flow does feed down to guide even pressure local features.  So wind to your back may well be telling you that a smaller area of low pressure is somewhere between to your left and in front of you... but that low pressure could be local: a building... a thunderstorm... even a tornado.  That said, as the pressure gradient gets greater, Coriolis is more and more marginalized, and the low pressure can be almost directly in front of you... and there are even rare circumstances where it is strong that the low can rotate backwards, and low pressure may be to your right.  As far as I know, this scenario only can maintain itself at all in strong thunderstorms, with the quite rare antimesocyclones and &lt;a href=&quot;https://www.washingtonpost.com/news/capital-weather-gang/wp/2013/06/05/the-rare-anticyclonic-tornado-in-el-reno-okla/?utm_term=.515516f94ccd&quot; rel=&quot;nofollow noreferrer&quot;&gt;anticyclonic tornadoes&lt;/a&gt;.  However, perhaps it could also happen on the microscale, such as around buildings, but those circumstances are no within my area of knowledge.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So all that put together:&lt;br&gt;&#xA;&lt;strong&gt;If indeed you can get away from those big buildings, are fairly removed from the regional impacts of mountains and smaller nearby terrain features, and ideally can escape areas with dense foliage... then if the wind is coming from behind you, you can be almost certain that large low pressure is to your left or front left (in the NH, right/front right in the SH)&lt;/strong&gt;... if you can find the wind direction.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;And if there isn't much wind?  Well then you're probably fairly near a high pressure center!  But that will make it fairly tough to diagnose exactly where high pressure centers/low pressure centers are in relationship to you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(And if there is a great deal of wind... well maybe you should just get inside, and turn on your tv to find out when the big tornado/hurricane/winter storm is going to end!)&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Other options:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;You could also use a barometer to diagnose falling/rising pressure trends.  Those indicate that a low/high is moving towards you.  However, this doesn't tell you what direction the low or high is located [though you can often make an educated guess based upon predominant wind flow; most pressure systems come from the west in the mid-latitudes, which include much of the US/Europe/Asia].&lt;/li&gt;&#xA;&lt;li&gt;As gansub noted in the comments, you could watch how atmospheric conditions evolve, such as the cloud patterns/types.  &lt;a href=&quot;https://www.youtube.com/watch?v=tsD6zkBMmck&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=tsD6zkBMmck&lt;/a&gt; is a reasonable description of what goes on around fronts, which could help alert you to incoming storms (both warm and cold fronts are dips of low pressure, and indicate a large low pressure system is coming).  The continuing lack of cloudcover might be an indication of high pressure in the vicinity.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-01-07T10:05:44.597" LastActivityDate="2017-01-07T10:05:44.597" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9416" PostTypeId="2" ParentId="9395" CreationDate="2017-01-07T10:51:31.670" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Are Helium 3 and 4 being produced by earth's core?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;tl;dr &lt;strong&gt;no.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The paper you are referring to has major flaws in it. Claims that should not be in any respectable scientific journal such as:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...the demise of the georeactor is approaching. Within the present level of uncertainty, one cannot say precisely when georeactor demise will occur, whether in the next century...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;or&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;At some point in time after the georeactor dies, there will be no geomagnetic field and life on Earth will never be the same.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;etc., have no place in a scientific article that is to be taken seriously by anyone. This is scaremongering that belongs in tabloids. This was publish in PNAS which is a reputable venue, so I don't know how it got through. Was this even reviewed? No idea. But let's talk about the actual science presented in the paper.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not an expert on nuclear reactions so I can't comment on that actual model presented in the paper, but I can comment on the assumptions that are simply wrong. His model assumes a certain volume of uranium that exists in the core. Such a &quot;block&quot; of uranium doesn't exist. Uranium doesn't go in the core. He says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The background as to why a large portion of the Earth's reservoir of uranium is expected to exist in the core, precipitate, and ultimately collect at the center of the Earth has been set forth in refs. 8–11...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But refs 8–10 are actually his own papers. So he made up a theory that uranium goes in the core, completely ignoring years of published experimental work by different groups saying that uranium does &lt;em&gt;not&lt;/em&gt; go into any significant amounts in the core, and then bases his story on that. This is wrong. Some related questions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/8214/725&quot;&gt;Why is uranium only in the crust, really?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/4798/725&quot;&gt;What percent of the Earth&amp;#39;s core is uranium?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also note the lack of neutrinos, as mentioned by David Hammen in one of the answers, something that should happen if this was true.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So your questions:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is Herndon correct...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No, he is not.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If not, what is their origin?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Mantle sources with different &lt;sup&gt;3&lt;/sup&gt;He/&lt;sup&gt;4&lt;/sup&gt;He ratios. There are many reasons for that. Mid ocean ridge basalts are mostly generated by melting of depleted mantle, that is, mantle that was already melted (at least) once. So it will not have too much of primordial &lt;sup&gt;3&lt;/sup&gt;He in it, and the ratio will be low. Hotspots such as Iceland or Hawaii tap a deeper mantle source that still has &lt;sup&gt;3&lt;/sup&gt;He in it, so the ratio will be higher. There are other factors that can modify the ratio. Episodes of depletion and recycling, metasomatism (by aqueous fluids or carbonatites, each with their own capability to transport U and Th), and some more than I can't think of at the moment. Anyway, there's no nuclear reactor in the core of the earth and we're not going to die due to its demise because it doesn't exist.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2017-01-07T10:51:31.670" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="9417" PostTypeId="2" ParentId="9412" CreationDate="2017-01-07T16:58:48.847" Score="3" Body="&lt;p&gt;&lt;em&gt;Caveat: I'm answering this in a popular context. There may be more technical definitions, which I'd be interested in hearing about.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems to be generally accepted that continents are not, themselves, islands. This is a common confusion in pub quiz questions, where people argue over whether the largest island in the world is Greenland, Australia, or (if somebody especially pedantic is around) the combined landmass of Europe, Asia and Africa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the question comes down to &quot;what is a continent&quot;? It's more of a political / historical / geographical unit than a topological one. If continents were demarcated by coastlines, then Europe, Africa and Asia would all be one. Additionally, many small mid-ocean islands, which are not on continental shelves, would end up being continents.&#xA;It's tempting to think of continents as relating to tectonic plates, but even if we disregard mid-continent faults and &quot;complicated&quot; areas, Europe and Asia are hard to separate.... and the 6 continents as currently thought of were pretty much set before plate tectonics was advanced as a theory. Wikipedia has an interesting article on historic boundaries between continents; &lt;a href=&quot;https://en.wikipedia.org/wiki/Boundaries_between_continents#Europe_and_Asia&quot; rel=&quot;nofollow noreferrer&quot;&gt;the one between Europe and Asia&lt;/a&gt; is especially ambiguous.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not aware of any definition of &quot;subcontinent&quot;, and have never heard this term used for anything other than the area around India, so I suspect this is also a political and historical term.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to answer the question: No, &lt;strong&gt;there is not a size-based distinction between islands and continents, although the smallest continent is indeed bigger than the largest island. The definition of an island would seem to be &quot;a landmass surrounded by water that is not thought of as a continent&quot;.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for &quot;islet&quot;, again, I'm not aware of any formal definition. However, the UN Convention on the Law of the Sea does distinguish between islands and &quot;rocks&quot;, where the latter are islets that are too small to be habitable. This is an important definition, because unlike islands, rocks are not considered when defining a nation's exclusive economic zone (the area in which they may control who fishes, drills for oil, and so forth).&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2017-01-07T16:58:48.847" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9419" PostTypeId="1" AcceptedAnswerId="9420" CreationDate="2017-01-08T09:51:57.670" Score="20" ViewCount="1576" Body="&lt;p&gt;I found what looks like a &quot;crystal ball&quot; in a meteorological station in the Vlădeasa mountains (Romania). What is its purpose? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Ur2Ww.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ur2Ww.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7270" LastEditorUserId="6298" LastEditDate="2017-01-10T22:18:36.067" LastActivityDate="2023-07-03T18:34:38.310" Title="What is this &quot;crystal ball&quot; located at a meteorological station?" Tags="|meteorology|weather-forecasting|instrumentation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9420" PostTypeId="2" ParentId="9419" CreationDate="2017-01-08T10:22:09.260" Score="33" Body="&lt;p&gt;It's a &lt;a href=&quot;https://en.wikipedia.org/wiki/Campbell%E2%80%93Stokes_recorder&quot;&gt;Campbell-Stokes sunshine recorder&lt;/a&gt;, used to record the times at which the sun is shining. It acts as a lens, focusing the sunlight onto a piece of card. If the sun is shining, the focused beam will burn a hole through the card at that point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a closer view of a sunshine recorder in Wendelstein, Bavaria:&#xA;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/4/43/Heliograph_wendelstein_2002_00a.jpg/640px-Heliograph_wendelstein_2002_00a.jpg&quot; alt=&quot;Sunshine recorder&quot;&gt;&#xA;&lt;sup&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Heliograph_wendelstein_2002_00a.jpg&quot;&gt;Wikimedia Commons&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And here's a used recording card with holes burned through it:&#xA;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/6/65/Sunshine_card_closeup.JPG/636px-Sunshine_card_closeup.JPG&quot; alt=&quot;Recording card&quot;&gt;&#xA;&lt;sup&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Sunshine_card_closeup.JPG&quot;&gt;Wikimedia Commons&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2017-01-08T10:34:04.937" LastActivityDate="2017-01-08T10:34:04.937" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9422" PostTypeId="1" CreationDate="2017-01-08T16:39:42.037" Score="4" ViewCount="47" Body="&lt;p&gt;The US EPA has a list of &lt;a href=&quot;https://www.epa.gov/haps/initial-list-hazardous-air-pollutants-modifications&quot; rel=&quot;nofollow noreferrer&quot;&gt;187 air pollutants&lt;/a&gt; that they consider &quot;hazardous&quot;.  These toxic pollutants are known or suspected to cause cancer or other serious health conditions.  How is it determined whether an air pollutant is hazardous? I'm mainly curious how the list of 187 pollutants was determined. Is there a testing process to determine toxicity that is used? or some other method that distinguishes a pollutant's toxicity?  I suspect it could've been done with just literature review, but then I would expect the list to be revised regularly based on health studies.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-01-08T16:39:42.037" Title="How is it determined whether an air pollutant is &quot;hazardous&quot;?" Tags="|air-pollution|hazardous|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9425" PostTypeId="1" CreationDate="2017-01-09T06:59:11.163" Score="3" ViewCount="133" Body="&lt;p&gt;What is the percentage of the Earth's warmth that the Earth's hot centre is responsible for? What would be the temperature of the atmosphere if the Earth's centre was 18° C (average temperature on the surface)?&lt;/p&gt;&#xA;" OwnerUserId="5016" LastEditorUserId="725" LastEditDate="2017-01-09T08:51:03.947" LastActivityDate="2017-01-09T20:57:24.463" Title="How much of the Earth's heat is caused by the hot centre?" Tags="|geophysics|temperature|core|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="9426" PostTypeId="2" ParentId="9425" CreationDate="2017-01-09T11:33:54.113" Score="4" Body="&lt;p&gt;Given the insulating effect of 6370 km of rock (the average radius of the Earth) &amp;amp; its low thermal conductivity, if the temperature at the center of the earth was 18 °C it contribution to warming the atmosphere would be negligible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The temperature at the center of the Earth is about &lt;a href=&quot;https://en.wikipedia.org/wiki/Geothermal_gradient&quot; rel=&quot;nofollow noreferrer&quot;&gt;7000 °C&lt;/a&gt;, while the average temperature of the surface is about &lt;a href=&quot;http://neo.sci.gsfc.nasa.gov/view.php?datasetId=MOD_LSTD_CLIM_M&quot; rel=&quot;nofollow noreferrer&quot;&gt;10 °C&lt;/a&gt;. So if the temperature at the Earth's center was 18 °C its contribution to the surface temperature would be exceedingly small.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="725" LastEditDate="2017-01-09T20:57:24.463" LastActivityDate="2017-01-09T20:57:24.463" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9427" PostTypeId="1" AcceptedAnswerId="9431" CreationDate="2017-01-09T14:07:54.110" Score="3" ViewCount="7058" Body="&lt;p&gt;When metamorphic rocks undergo pressure they are changed, but how are they changed? Do they become fragments of rocks? Doesn't that mean that the difference between sedimentary rocks and metamorphic rocks (when talking about fragment rocks) is that sedimentary rocks undergo weathering, which makes them fragments and metamorphic rocks undergo immense pressure which makes it into fragments?&lt;/p&gt;&#xA;" OwnerUserId="7285" LastEditorUserId="725" LastEditDate="2017-01-21T07:28:16.403" LastActivityDate="2017-01-22T09:08:10.357" Title="When metamorphic rocks undergo pressure, how are they changed?" Tags="|geology|rocks|metamorphism|" AnswerCount="4" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="9428" PostTypeId="1" AcceptedAnswerId="9432" CreationDate="2017-01-09T15:54:43.520" Score="5" ViewCount="150" Body="&lt;p&gt;I am using the outputs of the &lt;a href=&quot;http://www.weather.bg/0index.php?koiFail=txt/textAladin&amp;amp;lng=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;ALADIN meteorological model&lt;/a&gt;, in particular I need volumetric soil moisture. However, the output from ALADIN is in &quot;funny&quot; units - $\mathrm{kg/m}^2$ per top 1 cm. Is it acceptable to assume water density $\rho_w = 1000~\mathrm{kg/m}^3$ and calculate as follows:&#xA;$\frac{\mathrm{kg}}{\mathrm{m}^2.\mathrm{cm}}*\frac{100}{1000} = \frac{\mathrm{m}^3}{\mathrm{m}^3}$? So basically just take the values and divide them by 10? I don't need to be extra scientific, but I don't want to miss anything crucial.&lt;/p&gt;&#xA;" OwnerUserId="6643" LastEditorUserId="543" LastEditDate="2017-01-10T06:05:46.863" LastActivityDate="2017-01-10T06:05:46.863" Title="How to convert soil moisture units from meteorological model?" Tags="|soil-moisture|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9430" PostTypeId="2" ParentId="9427" CreationDate="2017-01-09T16:24:03.647" Score="6" Body="&lt;p&gt;Metamorphic rocks are formed when a rock (sedimentary, igneous or a previous metamorphic rock) comes under high pressure and/or temperature. Pressure and temperature forces the atoms to form new minerals and thereby a new kind of rock. It's not necessary fragmented, but the rock rather morph through &lt;em&gt;recrystallization&lt;/em&gt; into a new state in response to the pressure and temperature as the material reorganize. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Recrystallization_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Recrystallization&lt;/a&gt; doesn't remove any material, it's only a physical reorganization to compact the rock. If some change of the chemical composition occurs, it's called &lt;em&gt;metasomatism&lt;/em&gt;. In &lt;a href=&quot;https://en.wikipedia.org/wiki/Metasomatism&quot; rel=&quot;nofollow noreferrer&quot;&gt;metasomatism&lt;/a&gt; atoms are actually moved from one part of the rock or formation, often with water involved. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good &lt;a href=&quot;https://en.wikipedia.org/wiki/Petrology&quot; rel=&quot;nofollow noreferrer&quot;&gt;petrologist&lt;/a&gt; can usually determine what kind of parent rock, &lt;em&gt;protolith&lt;/em&gt;, that have been metamorphosed and to what degree, but sometimes it can be difficult do recognize the difference. At lower degrees of metamorphism, features of the original rock is preserved. E.g. you can see ripples and even fossils in slates or deformed structures from the source rock, but at higher degrees of metamorpism it's increasingly difficult to imagine how the parent material looked like. Gneiss formed from sandstone and granite can look very similar as the lihology represents the conditions of metamorphism, not the protolith. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It can also be difficult to recognize a metamorphic rock. A weathered slate and shale or even granite and gneiss can appear very similar in the field. However, the processes to form the rocks are different and with a closer look at the minerals it can be possible to understand what kind of process that formed the rock. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wcisW.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wcisW.png&quot; alt=&quot;Metamorphic phases&quot;&gt;&lt;/a&gt;&#xA;    &lt;em&gt;(1, Blueschist facies&#xA;    2, Eclogite facies&#xA;    3, Prehnite-pumpellyite-facies&#xA;    4, Greenschist facies&#xA;    5, Amphibolite-facies&#xA;    6, Granulite facies&#xA;    7, Zeolite facies&#xA;    8, Albite-epidote-hornfels facies&#xA;    9, Hornblende-hornfels facies&#xA;    10, Pyroxene-hornfels facies&#xA;    11, Sanidinite facies)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The temperature and pressure determine what metamorphic rock you get, but the chemical composition is inherited from the protolith. Degrees of metamorphism are called metamorphic &lt;em&gt;facies&lt;/em&gt;. This diagram shows at what depth and temperature a particular rock is formed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Igneous rocks are formed when a melt hardens to crystals and sedimentary rocks are formed from sediments. All rocks weather if exposed to water and air, and weathered material is transported by rivers to oceans where sandstone can be formed from the sand at the beach and shale from the finer sediments further away from the coast. Igneous rocks can be formed as hot magma intrudes the crust and slowly cools down and minerals are formed or form lava at volcanoes. This is known as the rock cycle and is one of the fundamental, but complicated, concepts in geology. You can read more about the rock cycle e.g. &lt;a href=&quot;http://www.cotf.edu/ete/modules/msese/earthsysflr/rock.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; to learn more about rock types and how they are formed. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-01-10T12:54:53.463" LastActivityDate="2017-01-10T12:54:53.463" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9431" PostTypeId="2" ParentId="9427" CreationDate="2017-01-09T16:31:15.657" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Metamorphic_rock&quot; rel=&quot;nofollow noreferrer&quot;&gt;Metamorphic rocks&lt;/a&gt; are changed by transformations deep underground. Being deep underground there is immense pressure and heat. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The transformations can be just crystal size of the particular mineral, or different minerals can be in fact formed. For a particular mineral there are also may be different crystal structures which depend on the pressure and temperature at which the crystal was formed. The different compositions and crystal structures would be shown on geochemical phases diagrams.  &lt;a href=&quot;https://en.wikipedia.org/wiki/Geochemical_modeling&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geochemical modeling&lt;/a&gt; could be used to predict the various reactions based on the temperature and pressure profile to which the material is subjected. &lt;/p&gt;&#xA;" OwnerUserId="4685" LastActivityDate="2017-01-09T16:31:15.657" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9432" PostTypeId="2" ParentId="9428" CreationDate="2017-01-10T01:37:58.967" Score="2" Body="&lt;p&gt;Your method looks OK, however, &lt;a href=&quot;https://water.usgs.gov/edu/density.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;water density varies with temperature&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not knowing exactly what your aim is or how accurate/fussy you want to be, you may want to consider using the density of water for its temperature rather than accepted average of $1000 kg/m^3$.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-01-10T01:37:58.967" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9433" PostTypeId="1" AcceptedAnswerId="9438" CreationDate="2017-01-10T10:16:10.783" Score="8" ViewCount="342" Body="&lt;p&gt;I am looking for academic papers which show future predictions of the North Atlantic Oscillation (NAO) by considering climate change and the various emission scenarios. Do you have any suggestions?&lt;/p&gt;&#xA;" OwnerUserId="6978" LastEditorUserId="111" LastEditDate="2017-01-11T14:50:33.243" LastActivityDate="2017-01-11T14:50:33.243" Title="North Atlantic Oscillation (NAO) future prediction - Academic papers?" Tags="|climate|climate-change|climate-models|reference-request|nao|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9434" PostTypeId="1" AcceptedAnswerId="9436" CreationDate="2017-01-10T11:06:35.313" Score="6" ViewCount="889" Body="&lt;p&gt;When you take a seismic reflection profile you take multiple shots and then stack them together around a common midpoint. Due to the extra distance travelled by the wide angle shots there is a moveout on time profile which you have to account for. Apparently, in order to apply the moveout correction you have to know (or guess) the velocity structure of the layers. I am confused as to why this is. Surely you know the extra distance travelled from the geometry of the shot you know the extra time because it is recorded in the arrivals so you should calculate the average layer velocity after lining up all the arrivals at the same time, not the other way around.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If someone can provide a detailed explanation of how common midpoint stacking and the moveout correction works that would be very helpful.&lt;/p&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2017-01-16T16:12:15.190" Title="How does moveout correction work in seismic reflection profiling?" Tags="|seismology|data-analysis|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9435" PostTypeId="1" AcceptedAnswerId="9441" CreationDate="2017-01-10T13:09:39.287" Score="7" ViewCount="638" Body="&lt;p&gt;Weather APIs often provide weather icons which symbolize the state of the sky at a given point, or as an average.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a &lt;strong&gt;standardized&lt;/strong&gt; way to define what the icon should be, based on quantifiable data such as cloud coverage or rain level (the idea being that, say, with over 50% cloud coverage a &quot;cloud&quot; is used, then with &gt; 1 mm rain, &quot;drops&quot; are added etc.) -- or is it left purely as an interpretation to the user? &lt;/p&gt;&#xA;" OwnerUserId="7288" LastEditorUserId="7288" LastEditDate="2017-01-10T16:09:34.840" LastActivityDate="2022-02-10T04:17:42.850" Title="Is there a standardized way to define weather icons based on quantifiable data?" Tags="|meteorology|weather-forecasting|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9436" PostTypeId="2" ParentId="9434" CreationDate="2017-01-10T13:27:08.550" Score="3" Body="&lt;p&gt;The offset is measured in meters, but the depth is still measured in time. The extra distance the wave have traveled to a longer offset is therefor also seen as an increased time in the &lt;em&gt;CMP-gather&lt;/em&gt; (Common Mid Point) and the extra time depends on the seismic velocity of the layers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the velocities are high, the moveouts are short. The longer offset, the longer distance the wave have traveled through the layer and the larger &lt;a href=&quot;https://en.wikipedia.org/wiki/Normal_moveout&quot; rel=&quot;nofollow noreferrer&quot;&gt;moveout&lt;/a&gt; correction is needed before stacking. Sometimes we mute long moveouts as they tend to be distorted and noisy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When we stack the traces in the CMP-gather, we need the reflectors to be at the same time and to do that, we perform NMO-correction (Normal MoveOut). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To find the right velocities to use for the NMO-correction, we can do a &lt;a href=&quot;https://en.wikipedia.org/wiki/Semblance_analysis&quot; rel=&quot;nofollow noreferrer&quot;&gt;semblance analysis&lt;/a&gt; to get the NMO-velocity. That is to simply try possible velocities and see at what velocity the reflector in the CMP-gather is aligned horizontally and gives the highest peak when summed for all traces. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The figure shows a synthetic CMP-gather to the left. A semblance velocity scan is performed and the peaks are shown in the middle plot. The velocities are picked as shown in the graph and are used to NMO correct the CMP-gather as seen in the seismogram to the right. When this is stacked, the reflectors will add up and the noise will be suppressed. So in theory, we don't need the velocity beforehand to perform NMO-correction. The moveout can be used to calculate a NMO-velocity model. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The figure is from &lt;a href=&quot;http://www.reproducibility.org/rsflog/index.php?/archives/334-Program-of-the-month-sfnmo.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Madagascar development blog&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LHfrT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LHfrT.png&quot; alt=&quot;Madagascar&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, if we know the velocities, eg from borehole data or refraction studies, we don't need to rely on computing heavy semblance velocity scans and uncertain velocity picking. Data are rarely so neat as this synthetic example shown here. Also, it's impossible to derive the gradually increasing velocity in a formation without internal reflectors. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The velocity we use to do NMO-correction is not the same as the velocity of the layer, but rather the additional velocity to the average needed to correct the moveout. To finally estimate the actual velocity of the layer, we can use e.g. &lt;a href=&quot;http://www.glossary.oilfield.slb.com/Terms/d/dix_formula.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dix equation&lt;/a&gt; to correct the velocities, but more accurate methods are usually used nowadays. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the basic application for stacking, but there is much more to it, you can read more e.g. &lt;a href=&quot;http://www.xsgeo.com/course/velan.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-01-16T16:12:15.190" LastActivityDate="2017-01-16T16:12:15.190" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9438" PostTypeId="2" ParentId="9433" CreationDate="2017-01-10T15:49:31.007" Score="8" Body="&lt;p&gt;A good start is the &lt;a href=&quot;https://www.whoi.edu/page.do?pid=83537&amp;amp;tid=3622&amp;amp;cid=54686&amp;amp;c=2&quot; rel=&quot;nofollow noreferrer&quot;&gt;article&lt;/a&gt; by &lt;a href=&quot;http://dx.doi.org/10.1038/ngeo352&quot; rel=&quot;nofollow noreferrer&quot;&gt;Goodkin et al. (2008)&lt;/a&gt; that relates past fluctuations of NAO to climate variability and argues that in the late 20th century NAO changes are much more dramatic as a result of enhanced energy (temperature) in the northern hemisphere.&lt;a href=&quot;https://i.stack.imgur.com/UZ4Fl.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UZ4Fl.jpg&quot; alt=&quot;Goodkin et al&quot;&gt;&lt;/a&gt; (Source &lt;a href=&quot;https://www.whoi.edu&quot; rel=&quot;nofollow noreferrer&quot;&gt;WHOI&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://dx.doi.org/10.1073/pnas.231391598&quot; rel=&quot;nofollow noreferrer&quot;&gt;Visbeck et al. (2001)&lt;/a&gt; describe the complex relationship between NAO and climate change associated with greenhouse gases:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Because global average temperatures are dominated by temperature variability over the northern land masses, a significant fraction of the recent warming trend in global surface temperatures can be explained as a response to observed changes in atmospheric circulation. Because the NAO is a natural mode of the atmosphere, one could argue that much of the recent warming is not related to the build-up of greenhouse gases in the atmosphere over the past century. This viewpoint, however, ignores the possibility that anthropogenic climate change might influence modes of natural variability, perhaps making it more likely that one phase of the NAO is preferred over the other.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As for predictions of the future effects cause by emission scenarios, that seems to be an ongoing topic of research. A couple of good starting point might be &lt;a href=&quot;http://dx.doi.org/10.1175/JCLI-D-11-00595.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Yeager et al. (2012)&lt;/a&gt; and the book chapter by &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/134GM09/summary&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hurrell et al. (2013)&lt;/a&gt; on the effects of climate change on NAO.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2017-01-10T15:55:40.933" LastActivityDate="2017-01-10T15:55:40.933" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9439" PostTypeId="2" ParentId="9387" CreationDate="2017-01-10T17:40:10.453" Score="4" Body="&lt;p&gt;The reliability is dependent on the quality, (for instance is the mineral reworked or porous and thus prone to contamination),  and size of the sample, (small samples result in poorer measurement). There is also of course the date range issue, use a sample that is too old or too new and the amount of each element is so tiny it can't accurately be measured. Thats why multiple measurements are always taken, if they vary wildly you know something is wrong. A good general rule for modern studies is expect a date to vary by ±5%. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Potassium-argon can be compared with relative dating methods like fossils and bedding as well as absolute dating methods like Uranium-Thorium, Uranium Lead, Rubidium Strontium, and even it's own dates to check for consistency. This is always being improved upon and multiple dates from different methods are sought whenever possible so there are tens of thousands of comparisons.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a good article about it &lt;a href=&quot;http://www.talkorigins.org/faqs/dating.html#radiomet&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. They also provide a good example &lt;a href=&quot;http://www.nrcresearchpress.com/doi/abs/10.1139/e88-106#.WHUbl_krLIU&quot; rel=&quot;nofollow noreferrer&quot;&gt;study&lt;/a&gt; (under the title a good example) which compares several methods for dating the K-T boundary and yields an error of about ~1 million years between them . Beware of older studies (1970's or older) which can have much larger error bars. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For other studies comparing lots of dates your best bet is large scale timescale reconstructions like this &lt;a href=&quot;http://archives.datapages.com/data/sepm_sp/SP54/A_Triassic_Jurassic_and_Cretaceous_Time_Scale.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;one&lt;/a&gt; which will compare dozens if not hundreds of individual dates. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2017-01-10T17:40:10.453" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9440" PostTypeId="2" ParentId="9435" CreationDate="2017-01-10T20:52:55.950" Score="7" Body="&lt;p&gt;The icons that are used are really just a visual way of describing the phrasing that is used in the forecast.  You can see an example of one set of icons offered by Weather Underground &lt;a href=&quot;https://github.com/manifestinteractive/weather-underground-icons/blob/master/dist/icons/black/icon-preview.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.  And they have &lt;a href=&quot;https://github.com/manifestinteractive/weather-underground-icons&quot; rel=&quot;nofollow noreferrer&quot;&gt;many different icon sets&lt;/a&gt; that you could choose from.  The phrases themselves are linked to specific ranges of probability of precipitation, cloud cover, or other factor.  &lt;a href=&quot;http://weather.gfc.state.ga.us/Info/WXexp.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;This site&lt;/a&gt; shows some nice tables that give some of those ranges (sample shown below):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aDyzv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aDyzv.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2022-02-10T04:17:42.850" LastActivityDate="2022-02-10T04:17:42.850" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="9441" PostTypeId="2" ParentId="9435" CreationDate="2017-01-10T22:21:52.903" Score="7" Body="&lt;p&gt;Some historical standards formed due to instrumentation.  Cloud cover observations were setup based upon okta, which are eighth fractions of the sky covered overhead during the past hour (perhaps 8 observations were taken/recorded by early instruments/observers).  This lead to the United States National Weather Service &lt;a href=&quot;http://www.weather.gov/bgm/forecast_terms&quot; rel=&quot;nofollow noreferrer&quot;&gt;using&lt;/a&gt; this table for reporting and forecasting:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2DzqR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2DzqR.png&quot; alt=&quot;NWS&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Likewise, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Rain_gauge#Tipping_bucket_rain_gauge&quot; rel=&quot;nofollow noreferrer&quot;&gt;tipping bucket rain gauge&lt;/a&gt; measured in 0.01 inch (0.25 mm) increments, so that influenced how precipitation categories were chosen.  &lt;a href=&quot;http://web.archive.org/web/20060110140456/http://www.met.tamu.edu/class/METAR/metar-pg9-ww.html#DRIZZLE&quot; rel=&quot;nofollow noreferrer&quot;&gt;This journal article&lt;/a&gt; states that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In  weather observations, drizzle is classified as (a) “very light”,&#xA;comprised of scattered drops that do  not  completely  wet  an&#xA;exposed  surface, regardless of duration; (b) “light,” the rate of&#xA;fall being  from  a  trace  to  0.25  mm  per  hour:  (c) “moderate,”&#xA;the rate of  fall being 0.25-0.50 mm per hour:(d) “heavy” the rate of&#xA;fall being more than  0.5  mm  per  hour.    When  the  precipitation&#xA;equals or exceeds 1mm per hour, all or part of the  precipitation  is&#xA;usually  rain;  however,  true drizzle  falling  as  heavily  as  1.25&#xA;mm  per  hour has been observed.  By convention, drizzle drops are&#xA;0.5mm or less in diameter”&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Showing that there is plenty of connection in the definitions of rain/drizzle intensities to the 0.25 mm baseline.&lt;/p&gt;&#xA;&lt;p&gt;However, while many organizations may work from this framework, there's no reason other organizations must base their wording and icons on these historical criteria.  They may wish to have more or fewer categories in their forecasts.   For example, Wunderground's API table shows that [&lt;a href=&quot;https://www.wunderground.com/weather/api/d/docs?d=resources/phrase-glossary&amp;amp;MR=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;current link&lt;/a&gt; now access protected, original information &lt;a href=&quot;https://web.archive.org/web/20180328124309/https://www.wunderground.com/weather/api/d/docs?d=resources/phrase-glossary&amp;amp;MR=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;]:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iAm1S.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iAm1S.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;They use just four cloud coverage icon categories, while their forecast wording options include clear, cloudy, mostly cloudy, mostly sunny, partly cloudy, partly sunny, and scattered clouds.  So they don't appear to match the standard NWS table.&lt;/p&gt;&#xA;&lt;p&gt;So long story short: &lt;strong&gt;There are some historical standards, but sites can take liberties in reporting it how they wish.  Looking through some of the APIs, it would definitely be nice if they would better indicate the actual criteria they use!&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-02-09T15:33:58.033" LastActivityDate="2022-02-09T15:33:58.033" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="9442" PostTypeId="2" ParentId="7193" CreationDate="2017-01-10T22:38:08.690" Score="5" Body="&lt;p&gt;The US &lt;a href=&quot;http://www.ncdc.noaa.gov/oa/ncdc.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCDC&lt;/a&gt; has this &lt;a href=&quot;https://www7.ncdc.noaa.gov/CDO/cdopoemain.cmd?datasetabbv=DS3505&amp;amp;countryabbv=&amp;amp;georegionabbv=&amp;amp;resolution=40&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt; to surface hourly global data which I was indeed able to find Napoli on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It appears, based upon &lt;a href=&quot;https://www.ncdc.noaa.gov/wdcmet&quot; rel=&quot;nofollow noreferrer&quot;&gt;this page&lt;/a&gt; describing the World Data Center For Meteorology, that there may be restrictions on using the data commercially outside of the United States.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-01-11T06:53:08.930" LastActivityDate="2017-01-11T06:53:08.930" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9443" PostTypeId="1" CreationDate="2017-01-11T06:35:32.753" Score="4" ViewCount="48" Body="&lt;p&gt;We often only hear of problems with the carbon, nitrogen &amp;amp; water cycles etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to know if there have been any observed problems with other cycles - for example, the iron cycle, magnesium cycle or potassium cycle, if these particular cycles exist, which could be attributed to have caused some major sustainability issues (e.g. loss of arable land)? I do not have much knowledge in this area.&lt;/p&gt;&#xA;" OwnerUserId="3241" LastEditorUserId="2470" LastEditDate="2017-01-11T11:19:00.300" LastActivityDate="2017-01-11T11:19:00.300" Title="A question about the disruption of global geochemical cycle in anthropocene" Tags="|biogeochemistry|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9444" PostTypeId="1" CreationDate="2017-01-11T09:38:05.913" Score="4" ViewCount="176" Body="&lt;p&gt;In a paper published in Nature Geoscience (&lt;a href=&quot;http://www.nature.com/ngeo/journal/vaop/ncurrent/full/ngeo2869.html#affil-auth&quot;&gt;paper&lt;/a&gt;)  the authors conclude : &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Declining precipitation in northern India is linked to Indian Ocean&#xA;  warming, suggesting a previously unrecognized teleconnection between&#xA;  ocean temperatures and groundwater storage.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What could be the physical explanation for such relationship . I understand that &lt;a href=&quot;https://en.wikipedia.org/wiki/Saltwater_intrusion&quot;&gt;sea water intrusions&lt;/a&gt; can take place in coastal regions ,  but how does temperature come into the picture ?&lt;/p&gt;&#xA;" OwnerUserId="594" LastActivityDate="2017-01-18T01:15:03.793" Title="Can ocean temperatures affect groundwater storage capacity ?" Tags="|meteorology|oceanography|groundwater|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9445" PostTypeId="5" CreationDate="2017-01-11T14:55:35.857" Score="0" Body="&lt;p&gt;The North Atlantic Oscillation: It is one of the most important interconnections in the northern hemisphere especially affecting Europe and North America. The NAO is characterized by a north-south dipole of anomalies, with one center around 35N in the North Atlantic and the other located over Greenland.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2017-01-11T14:55:35.857" LastActivityDate="2017-01-11T14:55:35.857" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9446" PostTypeId="4" CreationDate="2017-01-11T14:55:35.857" Score="0" Body="The North Atlantic Oscillation: It is one of the most important interconnections in the northern hemisphere especially affecting Europe and North America. The NAO is characterized by a north-south dipole of anomalies, with one center around 35N in the North Atlantic and the other located over Greenland." OwnerUserId="111" LastEditorUserId="111" LastEditDate="2017-01-11T14:55:35.857" LastActivityDate="2017-01-11T14:55:35.857" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9447" PostTypeId="2" ParentId="9444" CreationDate="2017-01-11T18:49:39.450" Score="2" Body="&lt;p&gt;Well without reading the article pointed because it costs/ no rights: warmer sea surface temperatures SST links usually with more precipitation via enhanced evaporation. But in some cases like the predicted decline in precipitation in eastern Mediterranean because of climate change happens even though warmer temperatures increase evaporation. This is simply because the changes in the intensity of average storms and changes in their storm track. The case in here seems to be similar by looking at the plotted precipitation pattern. The distribution of rain changes so that more water rains in southern India and so less water can rain in the northern parts of India. And I would guess that the total amount of precipitation has still risen.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastEditorUserId="6465" LastEditDate="2017-01-12T08:19:00.720" LastActivityDate="2017-01-12T08:19:00.720" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9448" PostTypeId="2" ParentId="4822" CreationDate="2017-01-12T05:42:10.117" Score="-8" Body="&lt;p&gt;Floating continents on a rotating sphere follow the &quot;right-hand rule&quot;. A dynamic force vector acts toward the north on a globe spinning counter clockwise, when looking down upon the north pole. I surmise that over eons, land masses have been relentlessly forced northward with a measurable angular momentum. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A casual glance at the tapered appearance of South America, Africa, Greenland and the Indian subcontinent add anecdotal evidence to the theory. South America looks like a bubble moving northward with greatest mass at the north and a thinning tail on the south end. India, again with a tapered southern edge, has been moving north so dramatically that the Himalaya mountains were shoved skyward.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've never heard this theory advanced by anyone, but it seems plausible to me. Alfred Wegener offered his tectonic plate theory in 1912. This would be a corollary to that.&lt;/p&gt;&#xA;" OwnerUserId="7296" LastActivityDate="2017-01-12T05:42:10.117" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9449" PostTypeId="1" CreationDate="2017-01-12T16:22:07.610" Score="5" ViewCount="111" Body="&lt;p&gt;Reactions in ocean floor hydrothermal systems are a significant contributor to the mass balance of several major elements in the oceans, in particular magnesium, calcium, sodium, potassium and sulfate. Magnesium and sulfate are removed from the circulating seawater and calcium, sodium and potassium and added.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the principal reactions which take place in hydrothermal systems to achieve the mass transfers stated above? I know that precipitation of magnesium silicate clays is significant for the loss of magnesium but I have but unable to find much information on the others.&lt;/p&gt;&#xA;" OwnerUserId="2570" LastEditorUserId="5594" LastEditDate="2017-01-17T10:17:14.443" LastActivityDate="2017-01-18T21:53:04.120" Title="What reactions change seawater composition in hydrothermal systems?" Tags="|oceanography|geochemistry|hydrothermal-vents|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9450" PostTypeId="1" CreationDate="2017-01-12T18:58:01.230" Score="10" ViewCount="139" Body="&lt;p&gt;The sun radiates a lot of charged particles to the Earth. When the magnetic field of the Earth lines up to the poles, we get the beautiful polar lights. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But are there as many negative charged as positive charged particles or vice versa, such that the Earth gets charged by the Sun?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="5372" LastEditDate="2017-01-13T09:18:44.613" LastActivityDate="2019-02-10T03:14:04.160" Title="Does the Earth receive a net charge from the aurorae?" Tags="|geophysics|solar-terrestrial-physics|electromagnetism|auroras|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9451" PostTypeId="1" CreationDate="2017-01-12T21:37:44.330" Score="9" ViewCount="15383" Body="&lt;p&gt;Why does the temperature rise when it is snowing? Is it due to:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;cloud cover&lt;/li&gt;&#xA;&lt;li&gt;snow requires humid air and warmer air can carry more humidity (so in this case it would be the other way around, i.e. it snows because it is warmer)&lt;/li&gt;&#xA;&lt;li&gt;something else?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="7298" LastActivityDate="2023-11-26T12:36:20.547" Title="Temperature rise when snowing" Tags="|temperature|snow|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9452" PostTypeId="2" ParentId="9451" CreationDate="2017-01-12T23:26:40.800" Score="0" Body="&lt;p&gt;I don't know if it actually gets warmer. I've never seen evidence for it, so a source for the claim would be nice. But I have heard the belief that it does. &#xA;It often &lt;em&gt;FEELS&lt;/em&gt; warmer for two reasons. First because rain and snow are caused when warmer air meets colder air so at least 50% of the time it is actually getting warmer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;And secondly there is sudden drop in humidity caused by precipitation, and cold dry air &lt;em&gt;feels&lt;/em&gt; warmer than cold humid air because it transfers heat slower. Although this effect tends to only be be noticeable if the air is above freezing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Add both of these together and sprinkle in  some confirmation bias and you have the common belief that it always gets warmer, when it doesn't. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now transforming water vapor (a gas) into a solid releases energy. The same thing happens when it rains. In both cases the effect is minor and &lt;em&gt;would not be felt at ground level&lt;/em&gt;. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2017-01-13T15:13:02.777" LastActivityDate="2017-01-13T15:13:02.777" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="9453" PostTypeId="2" ParentId="4822" CreationDate="2017-01-13T05:27:25.680" Score="3" Body="&lt;p&gt;In the attached JPL graphic from Heflin et al, 2007.9- every data point located south of the equator shows a northward component of motion (except the Nazca plate west of South America and a small portion of the Eurasian plate in Indonesia). Australia, for example, is moving dramatically northeastward, compared to other regions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9na4k.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9na4k.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If landmass evacuation from the southern hemisphere has progressed similarly for tens of millions of years, it should not be a surprise our world map looks as it does. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, as Pangaea disburses, continental material appears to be converging in the western Pacific and diverging from the mid-Atlantic Ridge. After emerging from a north-south line in the Atlantic pushing South America and Africa apart, landmass ostensibly meets on the opposite side of the earth in the Mariana subduction zone. This complex motion, combined with my northward angular momentum theory, creates the disjointed continental drift we observe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Again, this is a long held theory of mine. &lt;/p&gt;&#xA;" OwnerUserId="7296" LastActivityDate="2017-01-13T05:27:25.680" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9455" PostTypeId="2" ParentId="4822" CreationDate="2017-01-13T14:17:08.923" Score="-3" Body="&lt;p&gt;While I cannot give a good explanation, at least I can give additional information.&lt;br&gt;&#xA;Antartica, continent that is just in the south of the Earth, is completely surrounded by rifts, where new land in constantly in creation and pushing north and south. As result adjacent plates are forced north while Antartica rises. Therefore, that ridge helps to explain current land distribution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Probably in the future we'll see more land than now in the north hemisphere.&lt;/p&gt;&#xA;" OwnerUserId="5004" LastActivityDate="2017-01-13T14:17:08.923" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9456" PostTypeId="2" ParentId="9451" CreationDate="2017-01-13T15:20:59.987" Score="9" Body="&lt;p&gt;Snow fall can occur under several conditions. In this I am assuming conditions typical for mid to high latitudes. Association with cold-warm fronts are probably most common. Snow fall in mountainous areas can be associated with orogenic clouds and precipitation, when air is raised due to topography creating conditions for precipitation. In addition it is possible to have convective precipitation although such conditions are much more common during summer conditions yielding rain (and when severe e.g. hail). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So when snow fall occurs in association with warm fronts, one could expect a warming since warm air replaces the cold when the front s passing. My guess is that it is this that you have experienced. However, since it is also possible to obtain snow fall during the passing of a cold front the opposite may occur. The orographic conditions concern a more steady situation where the air is affected by  a mountain which is stationary so I would not expect large changes in air temperature unless the air moving across the mountains itself changed temperature for one or another reason. Convective snow fall would not likely yield marked changes in temperature as I see it since the snow would be created by vertical movement of warmer air, cooling to form the snow. I would rather expect a slight cooling, similar to what happens under a heavy rain shower in summer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in short, the warming you mention is not generally  associated with snow fall &lt;em&gt;per se&lt;/em&gt; but likely associated with the passing of a warm front.&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2017-01-13T15:20:59.987" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9457" PostTypeId="1" CreationDate="2017-01-13T16:07:51.730" Score="1" ViewCount="64" Body="&lt;p&gt;Is there any scientific evidence that exploitation of natural resources (fossil energies, forests etc.) affects rainfalls or sea level, which can represent extreme events?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I read IPCC 2014 report and I see some claims like not all climate scientists agree on a variable catastrophic event probability.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They wrote the following sentences :&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In the future, it is likely that the frequency of tropical cyclones&#xA;  globally will either decrease or remain unchanged, but there will be a&#xA;  likely increase in global mean tropical cyclone precipitation rates&#xA;  and maximum wind speed.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Is there any scientific references that justify this kind of claim ?&lt;/p&gt;&#xA;" OwnerUserId="2827" LastEditorUserId="111" LastEditDate="2017-01-13T17:00:31.823" LastActivityDate="2017-01-13T17:00:31.823" Title="Changes in rainfalls, sea level and tropical cyclones" Tags="|sea-level|tropical-cyclone|rainfall|reference-request|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9460" PostTypeId="2" ParentId="9451" CreationDate="2017-01-14T09:48:42.373" Score="3" Body="&lt;p&gt;Addressing your hypotheses in order, I'll start with (1) cloud cover. Here you can differentiate firstly between day and night time. While during the day, clouds will reduce heating of the ground by means of reflection of incoming solar radiation, during night, the clouds are the main contributor to thermal back radiation towards the surface and absorption of radiated heat by the surface. Thus, clouds rather balance the diurnal temperature curves that induce a warming effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7he1J.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7he1J.jpg&quot; alt=&quot;The graphic shows the energy balance of the earth. ~341W/m^-2 is the average solar radiation hitting the earth at the top of the atmosphere. Note, that downwelling radiation is not solely made up of water vapor but it is the main contributor&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) it has been already mentioned in another comment, that precipitation happens due to any sort of uplift, hence cooling of air and condensation to form precipitation as snow or rain. Now, what you describe, warming as a consequence of snowfall, can in my perspective be attributed to the condition of a warm (humid) airmass overpassing a cold (dry) airmass. Due to its lower density, the warm air is, generally speaking, pushed up over the cold air. Due to this cooling effect we experience cloud formation and, with elevated water vapor concentrations of the overpassing air mass, precipitation (e.g. snowfall).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, the important phenomenon in this condition is the overpassing of the warm airmass. This induces a general heating of the underlying cold front while continuosly loosing latent heat trapped in its water vapor and passing it off as snowfall or rain, thus heating the underlying atmosphere. The important factor is the contiuned energy input of the overpassing low pressure air mass. This can, if the conditions are right, lead to continued snowfall, which eventually will turn into rain, if the base temperature is close enough to zero.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In opposition, a cold front &quot;wedging&quot; into a warm, low pressure airmass, condensing the water vapor as rain or snow and leaving a cloudless high pressure area in its wake, will become actually colder after the initial snowfall, which will be also of much shorter duration (some hours of snowfall)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/es2Wr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/es2Wr.jpg&quot; alt=&quot;Cold front moving in a north westerly direction&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not too sure of the connection between precipitation from the uplifted warm air and heat transfer to the cold airmass, though it does seem logical to me. Any thoghts on that topic?&lt;/p&gt;&#xA;" OwnerUserId="7295" LastActivityDate="2017-01-14T09:48:42.373" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9462" PostTypeId="1" CreationDate="2017-01-15T10:39:00.923" Score="1" ViewCount="618" Body="&lt;p&gt;Why on a Polar Front Jet Stream does the core form on the tropical (warm air) side and not on the polar (cold air) side?&#xA;Thank you in advance.&lt;/p&gt;&#xA;" OwnerUserId="7091" LastActivityDate="2017-01-15T10:39:00.923" Title="Jet stream core" Tags="|meteorology|jet-stream|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9463" PostTypeId="1" CreationDate="2017-01-15T11:35:08.387" Score="7" ViewCount="910" Body="&lt;p&gt;According to &lt;a href=&quot;https://en.wikipedia.org/wiki/Soil_color#Causes&quot; rel=&quot;noreferrer&quot;&gt;wikipedia&lt;/a&gt;, the colour of soli is determined by proteins present in the soil! &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Soil color is influenced by the amount of &lt;strong&gt;proteins&lt;/strong&gt; present in the soil. Yellow or red soil indicates the presence of iron oxides. Dark brown or black color in soil indicates that the soil has a high organic matter content. Wet soil will appear darker than dry soil.However, the presence of water also affects soil color by affecting the oxidation rate. Soil that has a high water content will have less air in the soil, specifically less oxygen. In well drained (and therefore oxygen rich soils) red and brown colors caused by oxidation are more common, as opposed to in wet (low oxygen) soils where the soil usually appears grey.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The presence of specific minerals can also affect soil color. Manganese oxide causes a black color, glauconite makes the soil green, and calcite can make soil in arid regions appear white.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It sounds a bit strange to me. Pigments proteins do impart colour to the substances they are in (e.g. Haemoglobin in blood) but I wonder if there are any such proteins that could impart the variable colours to soil. Besides the following sentences in the mentioned paragraph do not mention of any protein. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is possible that the word protein is there by mistake?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;P.S. The book from where the sentence is quoted is unfortunately not available online.&lt;/p&gt;&#xA;" OwnerUserId="6215" LastEditorUserId="6215" LastEditDate="2017-01-15T13:30:35.447" LastActivityDate="2017-05-16T19:02:01.953" Title="Is the colour of soil determined by the 'proteins' present in soil?" Tags="|soil|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9464" PostTypeId="2" ParentId="9463" CreationDate="2017-01-15T11:57:58.360" Score="3" Body="&lt;p&gt;Soil is a collection of minerals and the color of soil is largely determined by the composition of its minerals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Protein is derived from biological sources. The only way proteins could affect the color of soil is if the soil also contained large quantities of biological material.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-01-15T11:57:58.360" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9465" PostTypeId="1" AcceptedAnswerId="16984" CreationDate="2017-01-15T19:38:17.943" Score="7" ViewCount="1016" Body="&lt;p&gt;I have been trying to evaluate the analytical solution for a wave travelling in a &lt;strong&gt;homogeneous&lt;/strong&gt;, &lt;strong&gt;infinite&lt;/strong&gt; media. For a given source $S(t)$, the wave-field can be calculated at a distance $r$, for a given velocity $v$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$W(r)=F^{-1} [-i \pi S(\omega)H_0^{(2)} (kr) ]$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here $F^{-1}$ represent inverse Fourier transform.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$S(\omega)$ is the frequency domain representation of $S(t)$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$H_0^{(2)} (kr)$ is the Hankel function of zero order and second kind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and $k$ is the wave number $(=\frac{\omega}{v})$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I followed this &lt;a href=&quot;https://scicomp.stackexchange.com/questions/8288/analytic-solution-2d-scalar-wave-equation-in-cylindrical-coordinates-numerical-i&quot;&gt;&lt;strong&gt;link&lt;/strong&gt;&lt;/a&gt; which demonstrate code in Python, however, I couldn't implement same in MATLAB. I also had doubts how it works. Since the fourier transform have positive as well as negative frequencies (i.e. $-f_{max}/2&amp;lt;f&amp;lt;f_{max}/2$) but the code in link takes frequencies between $0&amp;lt;f&amp;lt;f_{max}$ for calculating Hankal function.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I wrote following MATLAB code but got the wave-field  all entries as NaN..!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit1&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a little modification, I forced the first term of the Hankel function to be zero (since it was containing a NaN in the real part). Now it is working nicely but it produced two peaks.  I thought it to be similar to frequency shift effect, as observed after FFT for positive and negative frequencies, but it is not.  In this case amplitudes are reversed. Can anyone explain it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hOgJr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hOgJr.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit2&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I assume that the only the first peak in the solution is correct one and second arises because of some effect (which I don' know). Problem comes when I change the &lt;strong&gt;dt&lt;/strong&gt; (e.g. $dt \in 10^{-4}[1, 2, 3, 4,....,10]$) the shape and amplitude of the solution changes.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/BjvJ7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BjvJ7.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any help is appreciated.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;clc;    clear all;      close all;&#xA;&#xA;%% Parameter Setting&#xA;vel=2000;   % velocity of medium&#xA;r=1000;     % distance at which wavefield will be observed&#xA;% the final wavelet should appear at time, t=r/vel=0.5sec&#xA;&#xA;T=1;        % Total time&#xA;dt=.0001;   % time step&#xA;f0=25;      % central freq&#xA;&#xA;%% Create Source Wavelet&#xA;N = round(T/dt);        % No of samples&#xA;t0 = 5/(sqrt(2)*pi*f0);     % Zero time shift&#xA;t = dt*(0:N-1);             % time vector&#xA;tau = t-t0;     % time vector shifted by t0&#xA;src = (1 -2* tau.*tau * f0^2 * pi^2).*exp(-tau.^2 * pi^2 * f0^2);  %source     wavelet&#xA;&#xA;%%FT of signal&#xA;nfft=2^nextpow2(N);     % no of fft points&#xA;fmax=1/dt;              % max frequency &#xA;freq= fmax*(-nfft/2:nfft/2-1)/nfft;    % Freq vector:  -Fmax/2 &amp;lt; f &amp;lt; +Fmax/2 &#xA;&#xA;sw=fft(src,nfft)/nfft;                % fourier transform of wavelet, S(w)&#xA;sw_shift=fftshift(sw);      % shifting to make S(w) amplitude corrosponding to above &quot;freq&quot; vector &#xA;amp= abs(sw_shift);         % amplitude of the S(w)&#xA;&#xA;%% Green Function &#xA;%(I have taken only positive freq. since hankel func defined only for positive numbers.&#xA;% Suggestions please..May be I am wrong..!)                  &#xA;freq_new= fmax*(0:nfft/2-1)/nfft;&#xA;w=2*pi*freq_new;&#xA;const = -1i*pi;&#xA;H02 = besselh(0,2,w*r/vel);&#xA;H02(1)=eps;&#xA;GF = const*H02;&#xA;&#xA;%% Calculating Wavefield &#xA;%I have made Green Function (GF) symmetric and then multipled with source spectrum.&#xA;GF_new=[fliplr(GF),GF]; &#xA;WF= ifft(GF_new.*sw);&#xA;t_new=dt*(0:length(WF)-1);&#xA;&#xA;%% Plot&#xA;figure(); &#xA;&#xA;% Wavelet&#xA;subplot(2,2,1);     &#xA;plot(t,src);     title('\bf{Source wavelet}'); &#xA;xlabel('Time(sec)');    ylabel('Amplitude ')&#xA;&#xA;% Frequencies&#xA;subplot(2,2,2);   &#xA;plot(freq,amp);    title('\bf{Source freq spec}');  &#xA;xlabel('Frequencies(Hz)');  ylabel('Amplitude ')&#xA;&#xA;% Gneens Fkt&#xA;subplot(2,2,3); &#xA;plot(freq_new,abs(GF));   title('\bf{Green Function}'); &#xA;xlabel('Frequencies(Hz)'); ylabel('Amplitude ')&#xA;&#xA;% Wafefield&#xA;subplot(2,2,4);      &#xA;plot(t_new,real(WF));    title('\bf{Trace}');   &#xA;xlabel('Time(sec)');  ylabel('Amplitude')&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="5413" LastEditorUserId="-1" LastEditDate="2017-04-13T12:53:55.997" LastActivityDate="2019-10-16T19:02:00.267" Title="Analytical solution for seismic wavefield in MATLAB" Tags="|seismology|waves|seismic|matlab|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="9469" PostTypeId="1" AcceptedAnswerId="9479" CreationDate="2017-01-17T17:00:20.443" Score="5" ViewCount="1258" Body="&lt;p&gt;The image below was taken on a hike.  Circular patterns at bottom (it is flatter on this face and round otherwise) appear either man-made or possibly it is a fossil.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any idea what this could be?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/09t1N.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/09t1N.jpg&quot; alt=&quot;Rock of interest:&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7312" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T07:45:00.487" LastActivityDate="2019-08-28T07:45:00.487" Title="Circular patterns at bottom of rock, is it a fossil?" Tags="|fossils|paleontology|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="9470" PostTypeId="1" AcceptedAnswerId="9471" CreationDate="2017-01-17T17:29:33.873" Score="3" ViewCount="244" Body="&lt;p&gt;Recently &lt;a href=&quot;http://grist.org/article/leaping-blizzards-global-warming-produces-bigger-snowfalls/&quot; rel=&quot;nofollow noreferrer&quot;&gt;I read&lt;/a&gt; that the current extreme snowfall in northern temperate climate is caused by the increased evaporation due to the global warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Had any scientist predicted these extremes before they've been observed?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've found nothing about such predictions in the &lt;a href=&quot;https://en.wikipedia.org/wiki/History_of_climate_change_science#Scientists_increasingly_predict_warming.2C_1970s&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia article&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="5016" LastActivityDate="2017-01-21T09:47:54.637" Title="Had the climatologists predicted climate change as the deviations to both extremely cold and hot temperatures before?" Tags="|climate|climate-change|earth-observation|snow|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="9471" PostTypeId="2" ParentId="9470" CreationDate="2017-01-17T22:47:06.150" Score="4" Body="&lt;p&gt;The Intergovernmental Panel on Climate Change summarizes the state of scientific understanding of climate change every few years and at least as far back as 2002 has projected a range of changes in extreme weather.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the IPCC report for 2002, the Working Group II: Impacts, Adaptation and Vulnerability summarized the existing scientific understanding in may areas, including &quot;Climate Variability and Extreme Events&quot;:&#xA;&quot;Most studies of climate change impacts have focused on changes in mean climate conditions. However, global climate change is likely to bring changes in climate variability and extreme events as well. This is relevant here because decisionmakers often consider hedging strategies to be prepared for the possibility of low-probability but high-consequence events -- a risk management framework.  Features of projected changes in extreme weather and climate events in the 21st century include more frequent heat waves, less frequent cold spells (barring so-called singular events), &lt;strong&gt;greater intensity of heavy rainfall events&lt;/strong&gt;, more frequent midcontinental summer drought, greater intensity of tropical cyclones, and more intense El Nino-Southern Oscillation (ENSO) events.&quot; -&#xA;&lt;a href=&quot;https://www.ipcc.ch/ipccreports/tar/wg2/index.php?idp=61#1434&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate Variability and Extreme Events&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question is also addressed in section 2.5. &quot;Projected Changes in Climate Extremes could have Major Consequences&quot;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The vulnerability of human societies and natural systems to climate&#xA;  extremes is demonstrated by the damage, hardship, and death caused by&#xA;  events such as droughts, floods, heat waves, avalanches, and&#xA;  windstorms. While there are uncertainties attached to estimates of&#xA;  such changes, &lt;strong&gt;some extreme events are projected to increase in&#xA;  frequency and/or severity during the 21st century&lt;/strong&gt; due to changes in&#xA;  the mean and/or variability of climate, so it can be expected that the&#xA;  severity of their impacts will also increase in concert with global&#xA;  warming (see Figure SPM-2). Conversely, the frequency and magnitude of&#xA;  extreme low temperature events, such as cold spells, is projected to&#xA;  decrease in the future, with both positive and negative impacts.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7314" LastEditorUserId="725" LastEditDate="2017-01-19T00:17:31.470" LastActivityDate="2017-01-19T00:17:31.470" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9472" PostTypeId="2" ParentId="9262" CreationDate="2017-01-17T23:27:06.420" Score="8" Body="&lt;p&gt;Developing since 2014, the crack was projected in 2015 to lead to &quot;the largest calving event since the 1980s,&quot; according to &lt;a href=&quot;http://www.the-cryosphere.net/9/1223/2015/&quot;&gt;this report in The Cryosphere&lt;/a&gt; journal by glaciologists studying the region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From 2010, &lt;a href=&quot;http://www.the-cryosphere.net/4/77/2010/tc-4-77-2010.pdf&quot;&gt;&quot;Overview of areal changes of the ice shelves on the Antarctic&#xA;Peninsula over the past 50 years&quot;&lt;/a&gt; says that the largest break-up event in that period was the crack-up of Larsen B in 2002, which totalled 3,250 square kilometers -- approximately half the size of the area projected to break off from Larson C as a result of the current crack.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.jpl.nasa.gov/spaceimages/details.php?id=PIA20894&quot;&gt;&quot;Growing Crack in Antarctica's Larsen C Ice Shelf Spotted by NASA's MISR&quot;&lt;/a&gt; explains that the Multiangle Imaging SpectroRadiometer (MISR) instrument aboard NASA's Terra satellite examine's Earth's surface with nine cameras pointed at different angles, which provides information about the texture of the surface.  In composite images, the crack is clearly distinct from the surrounding ice shelf -- it is explained that the texture of the ice shelf is smooth and the texture of the sea ice on the ocean surface within the crack is rough.&lt;a href=&quot;https://i.stack.imgur.com/wwgjY.jpg&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wwgjY.jpg&quot; alt=&quot;These images from NASA&amp;#39;s Terra satellite show a large crack in the Larsen C shelf.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2017-01-17T23:27:06.420" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="9473" PostTypeId="2" ParentId="9406" CreationDate="2017-01-18T00:14:56.390" Score="3" Body="&lt;p&gt;There is an equation for a model of vertical variation in air temperature &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sNzdd.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sNzdd.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It unifies concepts from a whole range of sciences. You will need to know the sensible heat flux &lt;em&gt;H&lt;/em&gt; from the respective surface (which can be calculated as a result of the energy balance of where you are). Further you can calculate the volumetric specific heat capacity &lt;em&gt;pc(p)&lt;/em&gt; of air, which is approximately &lt;em&gt;1.2 kJ/(m³ K)&lt;/em&gt; and relate it to the shear velocity or friction velocity of your surface. This is finally related to the logarithmic measure of the term &lt;em&gt;(z-d)/zH&lt;/em&gt; where &lt;em&gt;z&lt;/em&gt; is the height of which you want to know the temperature and &lt;em&gt;d&lt;/em&gt; is the zero plane displacement. &lt;em&gt;zH&lt;/em&gt; finally is the Roughness of your surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This has to do with the fact, that heat transfer over surfaces usually is turbulent and not just determined by vertical convection. I recommend you to take a look at Campbell &amp;amp; Norman &quot;An Introduction to Environmental Biophysics&quot; (1998). It's a very comprehensive book and treats all the mentioned concepts. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm working on a basic computation of this at the moment but it still needs a little time. Once it's done, I'd be very excited to see if it actually is able to model the measured temperatures. I'll keep you updated on how it's going. &lt;/p&gt;&#xA;" OwnerUserId="7295" LastActivityDate="2017-01-18T00:14:56.390" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9474" PostTypeId="2" ParentId="9444" CreationDate="2017-01-18T01:15:03.793" Score="3" Body="&lt;p&gt;I think the abstract of the article addresses your question. Working backwards, it presents two direct causes of change in groundwater storage. The first is climatic - greater precipitation tends to increase storage and a decline in precipitation will reduce recharge and thus reduce storage. The second is the anthropogenic response to changes in climate (they focus on changes in precipitation but there may be a second effect of changes in air temperature). When there is less rain, more water will be pumped for irrigated agriculture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These two effects are then related to the way the change in precipitation is affected by change in ocean temperature. So changing ocean temperature changes the rainfall amounts and patterns. The rainfall reduction in northwestern India increases the amount of groundwater pumping needed for agriculture and decreases groundwater storage. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Methods have been developed to separate the climate and pumping effects on waterlevels (&lt;a href=&quot;http://link.springer.com/article/10.1007/s10040-015-1269-7&quot; rel=&quot;nofollow noreferrer&quot;&gt;Shapoori, V., et al. 2015&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-01-18T01:15:03.793" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9475" PostTypeId="2" ParentId="9262" CreationDate="2017-01-18T14:51:24.007" Score="9" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Is an iceberg the size of Delaware [6,451 square kilometers] actually remarkable, or something that just happens from time-to-time?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In March 2000 &lt;a href=&quot;https://en.wikipedia.org/wiki/Iceberg_B-15&quot; rel=&quot;nofollow noreferrer&quot;&gt;iceberg B-15&lt;/a&gt; formed which was 11,000 sq. km. and 295 km long.&lt;/p&gt;&#xA;&lt;p&gt;In October 1998 &lt;a href=&quot;https://en.wikipedia.org/wiki/Iceberg_A-38&quot; rel=&quot;nofollow noreferrer&quot;&gt;iceberg A-38&lt;/a&gt; formed which was 6,900 sq. km.&lt;/p&gt;&#xA;&lt;p&gt;A Delaware size iceberg would be the 3rd largest in the past 20 years.&lt;/p&gt;&#xA;&lt;p&gt;The 1990 article The &lt;a href=&quot;https://www.cambridge.org/core/journals/antarctic-science/article/div-classtitlethe-calving-and-drift-of-iceberg-b-9-in-the-ross-sea-antarcticadiv/49438894927051D46491A94C55E2E0BC&quot; rel=&quot;nofollow noreferrer&quot;&gt;calving and drift of iceberg B-9 in the Ross Sea, Antarctica&lt;/a&gt; &lt;em&gt;Antarctic Science&lt;/em&gt; Vol. 2 , pages 243-257 says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The largest iceberg in recent times&#xA;(95 km x 95 km) calved from the Larsen Ice Shelf in early 1986&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So a 9000 sq. km. iceberg broke off in 1986.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2004JC002843/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;Contribution of giant icebergs to the Southern Ocean freshwater flux&lt;/a&gt; says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;an iceberg of 10,000 km2 in area broke from the Amery ice shelf in 1964&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;According to &lt;a href=&quot;http://usatoday30.usatoday.com/weather/resources/coldscience/2005-01-20-1956-antarctic-iceberg_x.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Antarctica shed a 208-mile-long berg in 1956&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A record iceberg seen in Antarctic&lt;/p&gt;&#xA;&lt;p&gt;Little America V, Antarctica, Nov. 17- The U.S.S. Glacier, the Navy's most powerful icebreaker, has sighted an iceberg more than twice the size of Connecticut.&lt;/p&gt;&#xA;&lt;p&gt;The berg was sighted by the Glacier early this week about 150 miles west of Scott Island. The ship reported it was 60 miles wide and 208 miles long- or more than 12,000 square miles, as against Connecticut's 5,009.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So 12,000 sq. mi. or 31,000 sq. km. is the largest known iceberg.&lt;/p&gt;&#xA;&lt;p&gt;Both of the two previous references also mention a 1927 Antarctic iceberg that was 170 km long, but area is not given.  &lt;a href=&quot;https://books.google.com/books?id=y0zfAAAAMAAJ&amp;amp;q=%22largest%20iceberg%22&amp;amp;dq=%22largest%20iceberg%22&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwjdxoSxis3RAhUi4oMKHXGgAKU4ChDoAQhDMAc&quot; rel=&quot;nofollow noreferrer&quot;&gt;American Practical Navigator&lt;/a&gt;, says the 1927 iceberg was 100 mile long and 100 miles wide, so 25,000 sq. km.&lt;/p&gt;&#xA;&lt;p&gt;In summary, an iceberg the size of that contemplated in the OP can be expected on the once every 5-20 years time scale.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;update 7/12/2017&lt;/strong&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.projectmidas.org/blog/calving/&quot; rel=&quot;nofollow noreferrer&quot;&gt;according to the MIDAS project&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The calving occurred sometime between Monday 10th July and Wednesday 12th July 2017, when a 5,800 square km section of Larsen C finally broke away. The iceberg, which is likely to be named A68&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="248" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-07-12T12:38:36.080" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="9476" PostTypeId="2" ParentId="9403" CreationDate="2017-01-18T17:16:05.187" Score="-1" Body="&lt;p&gt;&lt;strong&gt;Disclaimer&lt;/strong&gt;: It a very crude way to do it.! Take it as the last resort.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It assumes that you know velocity for the shallower reflectors/layers. I will explain for one reflector and you can extend for deeper reflectors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Step 1&lt;/strong&gt;. You slice out the reflector event (in a trace) you want to find the velocity for. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Step 2&lt;/strong&gt;. Take a correlation with the respective trace in other time/depth domain part and find the max correlation time/depth. Here you may assume this time corresponds to the respective depth so you get total travel time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Step 3&lt;/strong&gt;. At this point you know the interval velocities for layers at the shallower depth, so you can find out the interval velocity for this layer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You start from the top and continue to bottom side. You may treat it as layer stripping.&lt;/p&gt;&#xA;" OwnerUserId="5413" LastActivityDate="2017-01-18T17:16:05.187" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9477" PostTypeId="1" CreationDate="2017-01-18T17:50:43.210" Score="4" ViewCount="266" Body="&lt;p&gt;A profile (clay soil) was excavated to a depth of 100 cm in the north of Tunisia. We have found limestone nodules, colluvium and alluvium. What I would like to know is the nature of the bedrock of this soil. Can we assert that there is a limestone bedrock?&lt;/p&gt;&#xA;" OwnerUserId="7315" LastEditorDisplayName="user12525" LastEditDate="2019-04-14T20:33:14.217" LastActivityDate="2019-04-14T20:33:14.217" Title="Does the existence of limestone nodules in a clay soil horizon indicate a limestone bedrock?" Tags="|geology|sedimentology|soil|bedrock|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9479" PostTypeId="2" ParentId="9469" CreationDate="2017-01-18T18:56:57.097" Score="4" Body="&lt;p&gt;The face of the rock with the round center portion looks strongly like a Rugosa or Horn Coral.  I suggest it is a Rugosa coral because of the center with the radial lines out from the center and the clear edge surrounding the radial lines.  See &lt;a href=&quot;https://en.wikipedia.org/wiki/Rugosa&quot;&gt;https://en.wikipedia.org/wiki/Rugosa&lt;/a&gt;.  &lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2017-01-18T18:56:57.097" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9480" PostTypeId="2" ParentId="9477" CreationDate="2017-01-18T19:18:13.273" Score="1" Body="&lt;p&gt;I can offer a counter-example. What if your soil sample is taken from the site of some lost ancient Roman buildings? The Romans built plenty in northern Tunisia, and like using &lt;a href=&quot;http://tigerprints.clemson.edu/cgi/viewcontent.cgi?article=1909&amp;amp;context=all_theses&quot; rel=&quot;nofollow noreferrer&quot;&gt;travertine limestone&lt;/a&gt;. A few long-destroyed buildings would explain the presence of limestone nodules in the soil while saying nothing about the bedrock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The point is there are many possible sources of limestone that are not the underlying bedrock. I don't think you can make that assumption. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="6703" LastEditDate="2017-01-18T19:39:30.903" LastActivityDate="2017-01-18T19:39:30.903" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9481" PostTypeId="1" CreationDate="2017-01-18T21:06:42.053" Score="0" ViewCount="134" Body="&lt;p&gt;They told us at school and still keep telling our kids that trees don't regulate their temperature, but &lt;a href=&quot;http://phenomena.nationalgeographic.com/2008/06/11/tree-leaves-keep-the-same-temperature-from-tundra-to-tropics/&quot; rel=&quot;nofollow noreferrer&quot;&gt;in 2008 it was discovered that they do&lt;/a&gt;. And to me it all makes sense now. It must have serious implications on urban planning and fight against climate change, what are they?&lt;/p&gt;&#xA;" OwnerUserId="7317" LastActivityDate="2017-05-19T18:13:11.670" Title="What are the implications of the recent discovery that plants regulate their temperature around 21°C?" Tags="|temperature|" AnswerCount="1" CommentCount="3" FavoriteCount="0" ClosedDate="2018-02-20T03:35:53.523" ContentLicense="CC BY-SA 3.0" />
  <row Id="9482" PostTypeId="1" CreationDate="2017-01-18T21:37:20.573" Score="8" ViewCount="1205" Body="&lt;p&gt;I drove through South Africa from Cape Town to Mozambique and noticed that almost all heights and mountains were no higher than approx 200-400 meters and had a flat top, just like the iconic Table Mountain. Why is this the case? &#xA;Thanks. &lt;/p&gt;&#xA;" OwnerUserId="7318" LastEditorDisplayName="user20559" LastEditDate="2021-06-24T11:28:17.213" LastActivityDate="2021-06-24T11:28:17.213" Title="Why are South African mountains short and flat?" Tags="|geology|mountains|regional-geology|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9484" PostTypeId="1" AcceptedAnswerId="9486" CreationDate="2017-01-19T14:13:05.923" Score="22" ViewCount="10116" Body="&lt;p&gt;I am procedurally generating planets for an open world space sandbox game. I am using a rough simulation of tectonic plates to create mountain ranges and other geological features.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A planet surface consists of several plates, which consists of tiles. The continental plates are randomly generated, with random initial elevation and drift velocities assigned.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tile elevations are generated by multiplying an envelope ( e^{ -d^2 } ) with a function for different types of plate boundaries and relative drift velocities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the sake of realism, is it possible to have a land-ocean divergent plate boundary? I could not find anything online. There also doesn't seem to be any examples on Earth from what I could find. Is it safe to assume that divergent boundaries only occur between land-land and ocean-ocean plate boundaries?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Update&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a rendering from the project. Red and green lines depict convergent boundaries. Land-land convergent boundaries produce mountains. Land-sea or sea-sea boundaries produces subduction zones. Blue lines denote a divergent boundary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/35Lnn.png&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/35Lnn.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm going to change the simulation so that divergent boundaries happen only at land-land and ocean-ocean boundaries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sorry for my ignorance about geology. I know this is a crude way to simulate plate tectonics.&lt;/p&gt;&#xA;" OwnerUserId="7321" LastEditorUserId="7321" LastEditDate="2017-01-19T17:16:19.880" LastActivityDate="2017-01-24T10:09:16.667" Title="Plate Tectonics: Is it possible to have an ocean-continent divergent boundary" Tags="|plate-tectonics|planetary-science|continental-rifting|ocean-ridge|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9485" PostTypeId="2" ParentId="9482" CreationDate="2017-01-19T14:56:04.983" Score="3" Body="&lt;p&gt;At least speaking for Table Mountain, from when I was at the top, it is actually not as flat as it appears from the surrounding landscape.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Table Mountain was formed from horizontal layers of sedimentary deposits. One hypothesis is that a collision between Africa and another oceanic plate occurred around 250 million years ago. The collision upheaved these layers. The apparent flat appearance of the top of the mountain probably reflects the original sedimentary layers. We see further evidence of this same collision, in the form of the Cape Fold Belt system, which stretches deep into the interior, for 700 km east and 200 km north of Cape Town.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Today, the mountain is composed of sandstone, which eroded into the shape we see today. This is similar to the shape of a flat clay river bank, without any plant growth, that is eroded by water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OpovN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OpovN.jpg&quot; alt=&quot;River bank erosion in Bangladesh&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same phenomenon is probably responsible for the geological features, that make the entire Cape region so spectacular.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not sure how related this is to what you saw in Mozambique.&lt;/p&gt;&#xA;" OwnerUserId="7321" LastActivityDate="2017-01-19T14:56:04.983" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9486" PostTypeId="2" ParentId="9484" CreationDate="2017-01-19T14:59:52.320" Score="14" Body="&lt;p&gt;The oceanic plates are themselves formed from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Plate_tectonics&quot;&gt;divergent boundary&lt;/a&gt;, so probably not. Even if a new rifting occurred exactly at the boundary, the result would eventually be that the ocean floor surrounds the divergent boundary. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A very simplified model of an ocean would have a &lt;a href=&quot;https://en.wikipedia.org/wiki/Mid-ocean_ridge&quot;&gt;divergent boundary&lt;/a&gt; in the middle. This oceanic spreading center might have basaltic volcanic islands along it, and two mirrored plates on each sides, pushing towards neighboring continental or oceanic plates. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OVQRD.png&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OVQRD.png&quot; alt=&quot;From wikipedia, as usual&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm trying to think about any oddity that would fit your description, but can't really come up with a good example. Locally you might have the conditions in &lt;a href=&quot;https://en.wikipedia.org/wiki/Triple_junction&quot;&gt;triple junctions&lt;/a&gt; eg. at Afar Triangle. Somehow, it could also describe parts of New Zealand and eastern Mediterranean, but it's very complex areas with more parameters controlling the rifting. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth is not controlled by any simple equation, its formed by 4.56 billion years of interaction between rocks, magma, life, atmosphere and even astronomic influence, so I'm not sure that divergent boundary never occurred between existing continental and oceanic plates, but at least it's very uncommon and couldn't last long. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A way to understand plate tectonics better, and maybe even a good inspiration for world building games, is to have a look at the (free) program &lt;a href=&quot;https://www.gplates.org/&quot;&gt;Gplates&lt;/a&gt; that is used by students and scientists to simulate tectonic history. Don't worry about your ignorance, interest is more important than knowledge. The game might be a good inspiration for someone to learn more about something really &lt;a href=&quot;https://www.google.com.au/imgres?imgurl=https%3A%2F%2Fwww.nasa.gov%2Fsites%2Fdefault%2Ffiles%2F1-bluemarble_west.jpg&amp;amp;imgrefurl=https%3A%2F%2Fwww.nasa.gov%2Fcontent%2Fgoddard%2Fearth-from-space-15-amazing-things-in-15-years&amp;amp;docid=t97PKMHHmGUgVM&amp;amp;tbnid=I6mUIX2BemSxbM%3A&amp;amp;vet=1&amp;amp;w=2048&amp;amp;h=2048&amp;amp;noj=1&amp;amp;client=firefox-b&amp;amp;bih=1082&amp;amp;biw=1831&amp;amp;q=earth%20from%20space&amp;amp;ved=0ahUKEwi4sYL4u87RAhWKHZQKHUr8B_QQMwgzKAMwAw&amp;amp;iact=mrc&amp;amp;uact=8&quot;&gt;awesome&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-01-19T15:08:32.873" LastActivityDate="2017-01-19T15:08:32.873" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9487" PostTypeId="2" ParentId="9481" CreationDate="2017-01-19T16:42:30.630" Score="1" Body="&lt;p&gt;I am shooting a bit for the hip here to be honest, this answer is opinion, not a researched position, but...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To imply that a object, be it plant, animal, or inanimate object with the ability to self regulate their temperature has the ability to have implications on climate change on a global scale, at least a positive one, ignores the physical laws of entropy.  That statement assumes that by positive effects means slowing of warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Entropy as a basic rule of physics always increases.  For this purpose, you can consider entropy to be the total energy in the system, with the energy of concern here being &quot;heat&quot;.  If a plant (or anything) raises its temperature, it also extracts that heat from somewhere else.  If the surrounding environment is warmer, it can do that by simply absorbing heat, otherwise it does that by using other energy by chemical or physical processes.  These processes always are net zero in entropy or increase entropy thus increase total system energy usually seen as heat.  The same is true when the plant needs to lower its temperature, it can exchange heat with surrounding environment or through physical or chemical means lower its temperature, but doing so will again either be net zero energy or an increase in energy/heat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plants do have an almost exemption of this rule though, they grow, and in doing so the store some energy, temporarily taking some of that energy out of the equation.  This stored energy, and thus heat, is then released when the plant dies and decays, is used as food, or when millions of years of the stored energy is used in the form of fossil fuels, again resulting in a net increase in total entropy in the system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plants can and are used for localized climate moderation, but the contribution that would be applied to their ability to regulate their own temperature I would think is somewhere between insignificant and a slight negative in terms of slowing global warming.  The more significant aspect is in areas like slowing ground heating of denuded areas, cleaning pollutants from the air, storing of energy for later use, and many other aspects of plant chemistry and relationship with its environment.  For instance, the shade provided by a single tree I would guess outweighs any effect cause by temperature regulation of many trees.  I would be happy to see any study to the contrary, but I do not see that as possible within the known laws of physics.&lt;/p&gt;&#xA;" OwnerUserId="6178" LastActivityDate="2017-01-19T16:42:30.630" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9488" PostTypeId="1" AcceptedAnswerId="16133" CreationDate="2017-01-19T17:01:35.760" Score="16" ViewCount="16146" Body="&lt;p&gt;Up until recently, I was under a (wrong) impression that the amount of planetary cumulative water resources was finite as I believed its escape from the atmosphere was impossible. I believed that, unlike other planetary resources, it was impossible to &quot;waste&quot; water as any waste would simply recycle itself in nature, i.e. municipal waste would be treated and get into the oceans from where it would eventually evaporate and precipitate back into continental waters renewing our water supply.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recently, I learned I was wrong and that there is such a phenomenon called &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_escape#Sequestration&quot;&gt;sequestration&lt;/a&gt; and that it is indeed possible for the total water resources on the planet to vary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am curious if there are metrics on how much water the planet has been losing (or gaining in case of a reverse phenomenon). Additionally, is there anything we can do to reduce this effect?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://sciencenordic.com/earth-has-lost-quarter-its-water&quot;&gt;This article&lt;/a&gt; says that we've lost a quarter of our water total but I was looking for more granular statistics.&lt;/p&gt;&#xA;" OwnerUserId="7323" LastEditorUserId="11908" LastEditDate="2019-03-11T20:58:53.287" LastActivityDate="2022-12-11T20:39:25.113" Title="How much water is the atmosphere losing to space?" Tags="|atmosphere|geophysics|water|magnetosphere|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9489" PostTypeId="2" ParentId="9470" CreationDate="2017-01-19T22:42:41.097" Score="1" Body="&lt;p&gt;Increased snowfall in a year or for a few years is weather, not climate change.  Reports such as &quot;this storm&quot; or &quot;this season&quot; being cause by, proving or disproving global warming are all anecdotal and serve no purpose other than to fuel those who do not understand the concepts but want ammunition to fight for their point of view to claim global warming as fact or fraud.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Global climate change, either towards warming or cooling promotes weather extremes.  Warming will cause change.  Some places will become colder while on average temperatures will rise.  Droughts, in general will increase, while some places will flood.  Storms though in general are all expected to be stronger.&lt;/p&gt;&#xA;" OwnerUserId="6178" LastActivityDate="2017-01-19T22:42:41.097" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9490" PostTypeId="1" AcceptedAnswerId="9491" CreationDate="2017-01-19T22:52:24.213" Score="6" ViewCount="92" Body="&lt;p&gt;Atmospheric mixing ratios of the hydroxyl radical have relatively short lifespans (on the order of microseconds). When modeling air quality or the weather, the time step is usually much larger than the the half life of hydroxyl. How is this computation numerically stable? Is the problem of numerical stability simply ignored?&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="543" LastEditDate="2017-01-19T23:38:46.033" LastActivityDate="2018-01-23T21:34:40.417" Title="Does hydroxyl radical chemistry in air quality models create numerical stability problems?" Tags="|atmosphere-modelling|numerical-modelling|atmospheric-chemistry|air-quality|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9491" PostTypeId="2" ParentId="9490" CreationDate="2017-01-19T23:36:38.113" Score="4" Body="&lt;p&gt;The hydroxyl radical chemistry is not modeled explicitly in air quality models, so numerical stability is not an issue.  Instead, OH is held in pseudo-steady-state.  For instance, see &lt;a href=&quot;https://www.cmascenter.org/cmaq/documentation/4.7.1/AQCHEM_NOTES.txt&quot; rel=&quot;nofollow noreferrer&quot;&gt;CMAQ's documentation&lt;/a&gt; which states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In CMAQ's gas phase, OH is assumed to be in pseudo-steady state, and it is not a transported species.  This is because hydroxyl radical reactions tend to be catalytic (e.g., consumption and production). In the aqueous phase chemistry, OH is absorbed by cloud water and in an open cloud model (i.e., the design approach currently employed), absorbed species (e.g., OH) would be replenished via gas-to-cloud partitioning. However, due to operator splitting, aqueous and gas-phase chemistry are not solved simultaneously. To account for this and other uncertainties in predicted OH aqueous phase concentrations (e.g., neglect of production reactions (H2O2 + hv -&gt; 2 OH) not currently implemented in aqchem), a steady-state assumption for OH is adopted in the aqueous chemistry routine.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Typically, if you are trying to model something like the hydroxyl radical, you would use a &lt;a href=&quot;http://www.atmos-chem-phys.net/10/9705/2010/&quot; rel=&quot;nofollow noreferrer&quot;&gt;box-model like MECCA&lt;/a&gt;, not a chemical transport model.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-01-19T23:36:38.113" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9493" PostTypeId="1" AcceptedAnswerId="9495" CreationDate="2017-01-20T06:56:50.140" Score="7" ViewCount="2119" Body="&lt;p&gt;My model (AGCM) does not compute w-wind (the vertical component of the wind velocity). However, I do have the following available variables from AGCM output:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;u-wind, v-wind, geopotential, omega and some other variables (e.g.,&#xA;temperature, specific humidity) at 23 pressure levels.&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;where u-wind and v-wind are the horizontal components of the wind velocity, &lt;a href=&quot;https://en.wikipedia.org/wiki/Geopotential&quot; rel=&quot;nofollow noreferrer&quot;&gt;geopotential&lt;/a&gt; is the potential of Earth's gravity, and omega is the solution to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Omega_equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;omega equation&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I would like to compute w-wind by using u-wind, v-wind, geopotential, omega. As suggested by &lt;em&gt;JeopardyTempest&lt;/em&gt; in the answer below, I can compute w-wind using the equation &lt;strong&gt;w = −ω/ρg&lt;/strong&gt;  . How reliable it would be if I don't use &lt;strong&gt;w = −ωRT/pg&lt;/strong&gt;?&lt;/p&gt;&#xA;" OwnerUserId="3194" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-01-23T16:21:11.033" Title="How to calculate w-wind?" Tags="|climate|models|wind|climate-models|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9494" PostTypeId="1" AcceptedAnswerId="9506" CreationDate="2017-01-20T07:38:31.153" Score="4" ViewCount="973" Body="&lt;p&gt;Where do magma chambers exist? Is it necessary that they exist in the asthenosphere where the circumstances of temperature and pressure are suitable for the rocks to be molten? Or they exist in places of shallow depth?&lt;/p&gt;&#xA;" OwnerUserId="6908" LastEditorUserId="1149" LastEditDate="2017-04-04T14:21:00.843" LastActivityDate="2017-04-04T14:21:00.843" Title="The position of magma chambers" Tags="|geology|volcanology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9495" PostTypeId="2" ParentId="9493" CreationDate="2017-01-20T11:07:59.483" Score="10" Body="&lt;p&gt;Omega, ω is closely related to w in meteorology.&#xA;It can be moved towards w using the chain (&lt;a href=&quot;http://www.sjsu.edu/faculty/watkins/omega.htm&quot; rel=&quot;noreferrer&quot;&gt;this reminder&lt;/a&gt; from Watkins at SJSU helped)...&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;ω = dp/dt = (dp/dz)(dz/dt) = (dp/dz)w &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&lt;em&gt;[where p is pressure, t is time, z is height, and w is vertical motion in height coordinates]&lt;/em&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Often in general meteorology you can estimate dp/dz using the &lt;a href=&quot;https://www.e-education.psu.edu/meteo300/node/7&quot; rel=&quot;noreferrer&quot;&gt;hydrostatic approximation&lt;/a&gt;, which assumes gravity and buoyancy approximately balance.  This allows the equations:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;dp/dz = −ρg  &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&lt;em&gt;[where ρ is air density and g is gravitational acceleration]&lt;/em&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And so would mean you can continue&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;ω = (dp/dz)w = −ρgw&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;which results in &lt;strong&gt;w = −ω/ρg&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Note that this is not always valid.&lt;/strong&gt;  As &lt;a href=&quot;https://www.google.com/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=1&amp;amp;cad=rja&amp;amp;uact=8&amp;amp;ved=0ahUKEwjJmqzPudDRAhUJLSYKHcarChQQFggdMAA&amp;amp;url=https%3A%2F%2Fwww.amazon.com%2FIntroduction-Dynamic-Meteorology-International-Geophysics%2Fdp%2F0123848660&amp;amp;usg=AFQjCNGdSbK_Pfo2P8HbJIyT5NckdVTUpg&amp;amp;sig2=7CCPxD8f00nU6vubKHTuJw&quot; rel=&quot;noreferrer&quot;&gt;Holton's An Introduction to Dynamic Meteorology, Volume 1&lt;/a&gt; suggests on &lt;a href=&quot;https://books.google.com/books?id=-ePQ6x6VbjgC&amp;amp;pg=PA202&amp;amp;lpg=PA202&amp;amp;dq=estimating%20w%20from%20omega%20qg&amp;amp;source=bl&amp;amp;ots=l3lT-YIsiq&amp;amp;sig=aOb6ZXDWv7f9Vp_IGUgxtqYDgWM&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwjk3rnptdDRAhXLRiYKHTzRA1Q4ChDoAQgoMAI#v=onepage&amp;amp;q=estimating%20w%20from%20omega%20qg&amp;amp;f=false&quot; rel=&quot;noreferrer&quot;&gt;page 20&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This condition of hydrostatic balance provides an excellent&#xA;  approximation for the vertical dependence of the pressure field in the&#xA;  real atmosphere.  Only for intense small-scale systems such as squall&#xA;  lines and tornadoes is it necessary to consider departures from&#xA;  hydrostatic balance.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That's a loose idea.  It's been a while, but basically as I remember it, hydrostatic is strongly valid when vertical acceleration (and thus vertical motion when looking near the surface) is much smaller in scale compared to the horizontal motions/accelerations.  So indeed, this is not true in tornadoes and in convection.  So you get very correct values for strong thunderstorms.  But it will help you diagnose regions of rising motion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can look a bit more towards breaking it down into more advanced detail and the mathematics of hydrostatic and how it fails in Doswell and Markowski's &lt;a href=&quot;http://www.cimms.ou.edu/~doswell/relbuoy/relbuoy.html&quot; rel=&quot;noreferrer&quot;&gt;paper&lt;/a&gt; on buoyancy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But, with such limited model output, not sure that you're looking to get into all of that detail, as I don't believe you'll find any extra help going those avenues with the variables you have.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With just slightly more information, most importantly temperature, you could use the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ideal_gas_law&quot; rel=&quot;noreferrer&quot;&gt;ideal gas law&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt; p = ρRT&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&lt;em&gt;[where R is the ideal gas constant of the gas under consideration and T is temperature in Kelvin]&lt;/em&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This would allow you replace the unknown density, and you'd then end up with:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;w = −ωRT/pg&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which you could then either further approximate R to be that for dry air = Rd = 287 J/Kkg, or even work up the adjustment your moisture content variable causes (though don't think doing so would offer much useful improvement as you've already got greater errors due to the failings of the hydrostatic approximation).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since you don't have temperature, it seems your only remaining option would be to plug in the density approximation for the level of interest from the approximated &quot;Standard Atmosphere&quot; &lt;a href=&quot;http://www.engineeringtoolbox.com/standard-atmosphere-d_604.html&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; (use the table where ρ is in units of kg/m^3).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It has been a long while since I've done this stuff, but I don't see any better options.  Unless somehow there's a way to work from the geopotential, maybe apply something like mass continuity in pressure coordinates, and get to something more complex to return something more correct for w.  But if there is, it outpaces me!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;So, long story short, it appears that your best hope is w = −ωRT/pg, but it won't be 100% reliable, particularly in strong convection.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-01-21T00:52:39.723" LastActivityDate="2017-01-21T00:52:39.723" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9496" PostTypeId="1" CreationDate="2017-01-20T19:06:40.873" Score="6" ViewCount="607" Body="&lt;p&gt;I'm a little mystified by &quot;angle of repose&quot; and the relationship to deposition and transport. In the following image, I detect 2 different angles of repose for the same material. How can this be?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/b6Sh4.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/b6Sh4.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clearly, the alluvial fan has a very shallow angle to it, not to mention the much steeper alluvial fans to the left. However, an intermittent stream has cut erosional channels through it and exposed a much steeper &quot;angle of repose&quot;, which, is likely more reflective of the true angle of repose for this material. So, how is the shallow angle of the alluvial fan possible?&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-01-21T07:41:09.780" Title="What, exactly, is angle of repose, and where is it in this image?" Tags="|sedimentology|geomorphology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9497" PostTypeId="1" AcceptedAnswerId="9498" CreationDate="2017-01-20T19:27:35.987" Score="5" ViewCount="4257" Body="&lt;p&gt;ECMWF model data comes in a hybrid GRIB format, that is, model level output is stored in GRIB2 messages, whereas surface data still uses GRIB1 format. Ungrib is unable to understand this hybrid GRIB format. Previous posts referred to ECMWF's grib-api which should be able to convert GRIB2 to GRIB1, but this doesn't seem to work since the 2013 update when 137 model levels were introduced. So my question is, how to get it working again?&lt;/p&gt;&#xA;" OwnerUserId="5891" LastEditorUserId="192" LastEditDate="2017-01-20T22:20:26.920" LastActivityDate="2020-02-04T12:58:59.283" Title="Running WRF with ECMWF GRIB2 model levels" Tags="|meteorology|models|atmosphere-modelling|wrf|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9498" PostTypeId="2" ParentId="9497" CreationDate="2017-01-20T19:27:35.987" Score="5" Body="&lt;p&gt;I finally solved this problem with the following steps:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Download the ECMWF data separately for model level variables (Q,T,U,V and geopotential) and surface variables. In this way, you will get 'pure' GRIB1 and 'pure' GRIB2 files rather than the hybrid type.&lt;/li&gt;&#xA;&lt;li&gt;Run ungrib twice: for the model levels files, use &lt;a href=&quot;https://gist.github.com/Peter9192/271978591ccab67a780ba4b93435f4a6&quot;&gt;this&lt;/a&gt; Vtable. For the surface file, use the 'old' Vtable.ECMWF_sigma. Between the two ungrib runs, change the ungrib prefix in the namelist.wps (e.g. I used prefix = 'FILE_ML' and prefix = 'FILE_SFC').&lt;/li&gt;&#xA;&lt;li&gt;Run util/calc_ecmwf_p.exe. This only works if the program can read both files. To achieve this, make sure that in the metgrid part of the namelist.wps, both input names are given (fg_name = 'FILE_ML','FILE_SFC','PRES',). Not sure whether 'PRES' makes a difference here, but since it will be used for metgrid I already put it there and it worked for me. 'PRES' are the files created by calc_ecmwf_p.exe. Note that you'll also need an 'ecmwf_coeffs' file for this step.&lt;/li&gt;&#xA;&lt;li&gt;Run metgrid, real and wrf as usual.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="5891" LastActivityDate="2017-01-20T19:27:35.987" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="9499" PostTypeId="2" ParentId="571" CreationDate="2017-01-20T20:37:02.027" Score="4" Body="&lt;p&gt;Around 80,000 barrels per year?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One way to have a rough estimate is to assume that the rate of oil formation has not changed since the Mesozoic. The vast majority of oil reservoirs formed during the last 250 million years. All we need to know is the total oil formed in that period: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;By 2009 we had consumed CB2009 = 1.0e11 to 1.35e11 oil tonnes. [&lt;a href=&quot;https://phys.org/news/2009-05-oil.html]&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://phys.org/news/2009-05-oil.html]&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The proven (90% chance of recoverability) reserves at that time were PR2009 = 2.2e11 tonnes. [&lt;a href=&quot;http://www.forbes.com/sites/judeclemente/2015/06/25/how-much-oil-does-the-world-have-left/#1688f3955dc5]&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.forbes.com/sites/judeclemente/2015/06/25/how-much-oil-does-the-world-have-left/#1688f3955dc5]&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The unproven (known reservoirs that are non profitable under present economic and technological conditions), may account for 4 times the proven reserves. Let's label that factor as UPFC=4.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the biggest uncertainty comes from estimating the &lt;strong&gt;unknown&lt;/strong&gt; oil reserves (reservoirs that are not yet known). Estimates are disperse, not even providing a precise order of magnitude. Depends, for example, on how you evaluate this figure: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/S0KlP.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/S0KlP.jpg&quot; alt=&quot;oil discoveries&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you assume that we are around half way of discovering all oil reservoirs accumulated on the Earth's sedimentary basins, then you just have to divide by the 250e6 years they took to form. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The average rate of oil formation is therefore:&lt;br&gt;&#xA;(CB2009 + PR2009) * UPFC * 2 / 250e6 = 11,200 tonnes/year = &lt;strong&gt;80,000 barrels/year&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that this is the average Mesozoic+Cenozoic oil formation rate minus the average oil degradation rate (oil is also lost after its formation through different natural processes). &lt;/p&gt;&#xA;" OwnerUserId="1379" LastEditorUserId="1379" LastEditDate="2018-01-23T14:45:11.623" LastActivityDate="2018-01-23T14:45:11.623" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9500" PostTypeId="2" ParentId="8133" CreationDate="2017-01-20T21:35:07.540" Score="2" Body="&lt;p&gt;Not in geological timescales. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The average &lt;strong&gt;residence time&lt;/strong&gt; of water in the oceans is around &lt;strong&gt;3,000 years&lt;/strong&gt;. This is because the world's anual precipitation is about 5e14 m3/yr, while the global ocean volume is 1.4e18 m3 [&lt;a href=&quot;http://hypertextbook.com/facts/2008/VernonWu.shtml]&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://hypertextbook.com/facts/2008/VernonWu.shtml]&lt;/a&gt;.&#xA;If you divide the second number by the first, you roughly get the 3000 yrs. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this approach assumes that water is well mixed in the oceans. Note that there are some exceptional seas that contain highly stratified waters where circulation is extremely slow, for example, in the Black Sea. Local residence times in those basins can become orders of magnitude longer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the other hand, the water forming the Antartica ice can spend about 20,000 years before being recycled to the atmosphere, because ice flow is slower than ocean circulation. &lt;/p&gt;&#xA;" OwnerUserId="1379" LastEditorUserId="1379" LastEditDate="2018-01-23T14:33:31.803" LastActivityDate="2018-01-23T14:33:31.803" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9501" PostTypeId="2" ParentId="9427" CreationDate="2017-01-21T07:26:52.113" Score="2" Body="&lt;p&gt;The existing answers are correct but I think they miss an important aspect of your question, which is the effect of pressure.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Do they become fragments of rocks?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No. Fragmentation of rocks is a relatively low temperature and pressure process. This is the kind of stuff you would see in near-surface environments. Once rocks become hot under pressure, they are no longer brittle but are ductile. This means they can bend and flow. Think of chocolate: put it in the freezer and it's hard as a rock, but if you take it out (when it's still solid) it becomes easier to bend it and shape it with your hands.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Same with rocks. A very common feature of metamorphic rocks is folding:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/y6aXZ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/y6aXZ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;sup&gt;(&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Agiospavlos_DM_2004_IMG003_Felsenformation_nahe.JPG&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Doesn't that mean that the difference between sedimentary rocks and metamorphic rocks (when talking about fragment rocks) is that sedimentary rocks undergo weathering, which makes them fragments and metamorphic rocks undergo immense pressure which makes it into fragments? &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No. The immense pressure actually works well to hold everything together instead of fragment them. There is some fragmentation in metamorphic rocks, but it's usually manifested as faulting rather than fragmentation into pieces (also known as brecciation). Here's an example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/m7i2Q.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/m7i2Q.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;sup&gt;(&lt;a href=&quot;http://www.sci.ccny.cuny.edu/~mcesaire/earthhistory.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-01-21T07:26:52.113" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9502" PostTypeId="2" ParentId="9496" CreationDate="2017-01-21T07:41:09.780" Score="4" Body="&lt;p&gt;Geological materials such as sediments are never totally homogeneous. There will always be softer and harder regions within sedimentary deposits.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fact that erosion channels have been created is due to the force/energy of the water creating the channels, the extent of the force the water had when it created the channels, the softness of the material being gouged out and the hardness and cohesion of the material left behind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The angle of the walls of the channels is not sustainable and over time the walls will slump (fail) to the lower angle of repose you see for the overall deposit. When this occurs the floors of the channels will be filled with the slump material.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the meantime, when more rain falls, the runoff will naturally flow in the extant channels - the water taking the path of least resistance. The water will flush out the loose slump material and if the force of the water is great enough it may also widened the channel and eventually cause more material to slump into the channel.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A material's angle of repose is a function of its cohesion and it is the overall/average angle the material lies at over a long period of time.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-01-21T07:41:09.780" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9503" PostTypeId="2" ParentId="9470" CreationDate="2017-01-21T09:40:08.843" Score="0" Body="&lt;p&gt;The article states snowmageddon 2010. 2010 was in the low phase of the 11 year sunspot cycle. 2016-7 were in the high phase and have been the hottest years on record. Snow is only precipitation, precipitation is expected to be less predictable and subject to more extremes of drought and high rainfall. If you want to learn more about that, read about global warming causing destabilized and extreme weather. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A better reason for snowmaggedon is this:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/cUxPf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cUxPf.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cFQGy.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cFQGy.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2017-01-21T09:47:54.637" LastActivityDate="2017-01-21T09:47:54.637" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9504" PostTypeId="2" ParentId="9427" CreationDate="2017-01-21T10:45:13.160" Score="2" Body="&lt;p&gt;Metamorphic can have been halfway to the state of lava for a short time, it may have been like quite tough dough of bread. You can imagine the viscosity of it to be the same as ordinary glass which is at 200 degrees, if you have a window at 200 degrees, you can bend it into a U shape in a time ranging from 20 minutes to 20 seconds depending on the temperature it is at, it becomes more malleable. instead of sand, metamorphic is hot limestone/clay/pebbles...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The dough slowly moves and deforms, for example by pressure of buckling tectonics from distant tectonic shocks like rising mountain chains. The chemicals inside the dough disamalgamate and coagulate into chemicals that have easy bond affiliation. Every chemical reacts differently and has more or less strong bonds at a set pressure of metamorphism, different blobs inside the metamorphic rock may be more or less mobile and viscous. You get crystals of different sizes of new materials, more often roundish, sometimes flat (gneiss) indicating the flow/pressure in the dough, the crystals branch out not that differently from ice crystals, they recrystallize re-mineralize. The time and pressure of metamorphosis vary a lot and determine the level of change that happens. &lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2017-01-22T09:08:10.357" LastActivityDate="2017-01-22T09:08:10.357" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9505" PostTypeId="1" AcceptedAnswerId="9507" CreationDate="2017-01-21T16:20:51.240" Score="10" ViewCount="1120" Body="&lt;p&gt;Does the composition of the crust of Mars roughly correspond to that of the crust of Earth. That is, is the elemental abundance in decreasing order silicon, oxygen, aluminum, etc.?&lt;/p&gt;&#xA;" OwnerUserId="7335" LastEditorUserId="94" LastEditDate="2017-01-21T16:31:52.173" LastActivityDate="2022-05-28T03:47:15.490" Title="Composition of Martian Crust" Tags="|geochemistry|crust|mars|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9506" PostTypeId="2" ParentId="9494" CreationDate="2017-01-21T16:43:05.063" Score="2" Body="&lt;p&gt;Magma chambers can exist at a range of depths from very deep to very shallow.  Only requirement that is really necessary is that there be enough pressure from overlying rock strata to keep the magma chamber from reaching the surface and erupting/exploding.  Volcanoes typically represent a slow leak of molten magma.&#xA;Even large Volcanic eruptions will only expel a fraction of the magma available.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are several important geological factors that will control the size. location, and depth of a magma chamber:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Magma buoyancy: Density of the magma (Dissolved gases/liquid and chemical composition vs density of the surrounding host rock.&lt;/li&gt;&#xA;&lt;li&gt;Integrity of the overlying host rock: tectonic settings, fault and fracture patterns, how seismically active is the local region.&lt;/li&gt;&#xA;&lt;li&gt;Rate of melting: dependent upon source rock composition, heat flow, depth of source material.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Back in the early 1990s, Japanese researchers imagined magma plumes near the lower mantle  / outer core boundary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.scientificamerican.com/article/more-than-one-magma-chamber-found-to-feed-hawaii-s-kilauea-volcano/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; is an article discussion shallow and deep Magma sources for the kilauea, Hawaii. As this article suggests, magma can originate at depth and migrate upward and supply shallow chambers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Facts on the &lt;a href=&quot;http://www.yellowstonepark.com/explore/volcanos/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Yellowstone volcanic complex&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-01-21T16:43:05.063" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9507" PostTypeId="2" ParentId="9505" CreationDate="2017-01-21T23:20:13.147" Score="6" Body="&lt;p&gt;The most abundant elements on Earth are:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;Element  Approximate % by weight&#xA;&#xA;Oxygen        46.6&#xA;Silicon       27.7&#xA;Aluminum       8.1&#xA;Iron           5.0&#xA;Calcium        3.6&#xA;Sodium         2.8&#xA;Potassium      2.6&#xA;Magnesium      2.1&#xA;All others     1.5&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Source:&lt;a href=&quot;http://hyperphysics.phy-astr.gsu.edu/hbase/Tables/elabund.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://hyperphysics.phy-astr.gsu.edu/hbase/Tables/elabund.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Based on data from a number of NASA and ESA spacecraft and rovers,&#xA;(Fine summary on wikipedia: &lt;a href=&quot;https://en.wikipedia.org/wiki/Composition_of_Mars&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Composition_of_Mars&lt;/a&gt;). The four top elements for the crust are most likely the same. They are roughly the same on Mars and Earth and may be in the basic proportions&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Oxygen&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Silicon&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Aluminum&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Iron&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I would expect at some point that the relative abundance of elements on Mars to deviate from that on Earth based on the following differences:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Earth and Mars were most likely formed at two very different distances from the center of our solar system.  This may have significantly affected the elemental abundances between the two planets.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Earth has had significant amounts of water since from very early in its history, as recorded by some of the oldest rocks on Earth which are meta-sedimentary deposits in Australia.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;We do not known how much water has ever been on Mars. Mars is currently very dry.  Water plays a big role in element distribution on Earth and my guess is water will have played a smaller role on Mars.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Lastly, I am becoming convinced that biologic activity has also significantly affected element distribution on Earth.  Bacteria/&lt;a href=&quot;https://en.wikipedia.org/wiki/Archaea&quot; rel=&quot;nofollow noreferrer&quot;&gt;Archaea&lt;/a&gt; have been found in deep rocks in South African gold mines, which is remarkable. Bacteria and Archaea may play a larger role in various geological processes than traditionally thought.  The Mantle is no longer viewed has dry and sterile.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Life and past life on Mars (even as  Bacteria or Archaea) are yet to be verified.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="12903" LastEditDate="2022-05-27T17:24:33.087" LastActivityDate="2022-05-27T17:24:33.087" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="9508" PostTypeId="1" AcceptedAnswerId="9513" CreationDate="2017-01-22T00:30:00.840" Score="7" ViewCount="646" Body="&lt;p&gt;Arthur C. Clarke, who correctly guessed there would be liquid water on Europa, posited a diamond core for Jupiter. Is this possible?&lt;/p&gt;&#xA;" OwnerUserId="7335" LastEditorUserId="6129" LastEditDate="2020-05-09T12:42:18.567" LastActivityDate="2020-05-09T12:42:18.567" Title="Diamond at the core of Jupiter" Tags="|geochemistry|planetary-science|diamond|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="9509" PostTypeId="1" CreationDate="2017-01-22T01:15:06.043" Score="5" ViewCount="196" Body="&lt;p&gt;What is the probability of the Yellowstone supervolcano erupting during any given year? I had heard that it erupts once every 100,000 years. Does that mean there is a .001% chance of it erupting during any given year?&lt;/p&gt;&#xA;" OwnerUserId="7335" LastActivityDate="2017-01-24T12:45:51.517" Title="Yellowstone Eruption Possibility?" Tags="|volcanology|volcanic-hazard|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9510" PostTypeId="1" CreationDate="2017-01-22T01:47:22.617" Score="8" ViewCount="260" Body="&lt;p&gt;I'm writing some lore for a fictional world, which is set in the 50's early 60's roughly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing I'd like to bring is a fairly grounded explanation for the creation of the planet and the universe, as understood by scientists in the fictional setting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What did we know about these topics back in the 50's? How did we used to believe the planet were formed?&lt;/p&gt;&#xA;" OwnerUserId="7336" LastEditorUserId="477" LastEditDate="2017-01-23T11:09:15.657" LastActivityDate="2020-08-21T14:35:20.150" Title="1950's - 60's Earth Science" Tags="|earth-history|planetary-formation|history-of-science|history|" AnswerCount="0" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="9511" PostTypeId="1" AcceptedAnswerId="9512" CreationDate="2017-01-22T03:16:23.790" Score="5" ViewCount="4632" Body="&lt;p&gt;Has the Earth had it's wobble that causes the seasonal variation in solar energy in the northern and southern hemispheres for it's entire history? Is this variation evident in the geologic record or is it an open question? Could a meteor impact like that which killed the dinosaurs 66 million years ago have altered or created the wobble? Are there any factors dampening or increasing the seasonal wobble over time?&lt;/p&gt;&#xA;" OwnerUserId="7335" LastActivityDate="2018-04-21T07:33:42.323" Title="Have the seasons always been?" Tags="|seasons|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9512" PostTypeId="2" ParentId="9511" CreationDate="2017-01-22T04:53:38.437" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;Has the Earth had it's wobble that causes the seasonal variation in solar energy in the northern and southern hemispheres for it's entire history?&lt;/em&gt; &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;First it depends on how you define the &quot;entire history&quot; of the earth. There was a pre-earth that was hit by a Mars sized body. The collision fragments ultimately collapsed into the present earth and moon. Exactly how massive the pre-earth was and its orbital parameters are &quot;unknown&quot;, meaning we know the parameters with much less precision than we know the parameters today.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second there are two factors here. The seasonal (yearly variation) is caused mostly by the earth's axial tilt even though the distance between the earth and sun varies a bit since the earth's orbit is an ellipse rather than a circle. However the &lt;em&gt;wobble&lt;/em&gt; of the earth is better better described as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Axial_precession&quot; rel=&quot;nofollow noreferrer&quot;&gt;precession of the earth's axis&lt;/a&gt; and it currently has a period of about 26,000 years. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;Is this variation evident in the geologic record or is it an open question?&lt;/em&gt; &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There is evidence in geological record for season and precession changes for the present earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Isotopic composition of glacial ice and ocean sediments reflect yearly temperature variations. The yearly temperature changes also cause seasonal changes in the distribution of the earth's weight which effect the precession and tilt. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lava cools leaving imprints of the instantaneous magnetic field of the earth over geological time. The interaction of the magnetic field drift and reversal, the precession of the earth, the axial tilt of the earth, and the plate movement of the earth is not well understood. It is basically governed by chaotic system interactions. For example plate movement can cause earthquakes which are as of yet unpredictable. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Again what the precession and tilt were like for the &quot;pre-earth&quot; is mostly a mystery. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;Could a meteor impact like that which killed the dinosaurs 66 million years ago have altered or created the wobble?&lt;/em&gt; &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The impact that created the moon was with a Mars sized body and definitely effect the earth's precession and tilt.   &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;Are there any factors dampening or increasing the seasonal wobble over time?&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Moon damps the tilt over geologic time. The instantaneous flow of the liquid magma inside the earth may increase or decrease the precession and/or tilt, but as the earth cools the overall effect is to decrease both. &lt;/p&gt;&#xA;" OwnerUserId="4685" LastEditorUserId="7335" LastEditDate="2017-01-22T16:09:53.210" LastActivityDate="2017-01-22T16:09:53.210" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9513" PostTypeId="2" ParentId="9508" CreationDate="2017-01-22T17:15:49.833" Score="11" Body="&lt;p&gt;I would think this is questionable, though we don't have a definitive answer yet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We usually think Jupiter has a roughly solar composition, which according to the solar abundance measurments of &lt;a href=&quot;http://adsabs.harvard.edu/abs/2009ARA%26A..47..481A&quot;&gt;Asplund et al. 2009&lt;/a&gt; would mean the total carbon mass of Jupiter is about $10^{-3}$ of Jupiter's total mass. So there's roughly $0.3$ Earth masses of carbon floating around in Jupiter.&lt;br&gt;&#xA;Next we need an idea of where this stuff is floating around.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We know that Carbon is floating around in Jupiter's atmosphere and is &lt;a href=&quot;https://dx.doi.org/10.1016%2FS0032-0633%2802%2900144-7&quot;&gt;enriched&lt;/a&gt; relative to solar values by around a factor of $\sim3$, which corrects our estimate of total carbon in Jupiter to roughly one Earth mass, if Jupiter is well-mixed.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The keyword here is &quot;well-mixed&quot;. If carbon atoms stay solved in hydrogen at high pressures in Jupiter's core, then no diamonds can be formed. Only if there is a &lt;a href=&quot;http://www.pnas.org/content/105/32/11035.full&quot;&gt;rain-out similar to helium&lt;/a&gt; (see also the phase diagram for &lt;a href=&quot;http://lasp.colorado.edu/~bagenal/3720/CLASS17/PhaseDiag.jpg&quot;&gt;hydrogen and helium-mixtures&lt;/a&gt;) then droplets or other accumulations of carbon can form, which will be pressed into diamonds.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The research however at the moment does not focus very much on carbon dissolution at high pressure, so I cannot cite anything reliable on what carbon will do. The reason for this is that the above cited helium-rainout and &lt;a href=&quot;https://arxiv.org/abs/1111.6309&quot;&gt;core erosion&lt;/a&gt; which are considered important at the moment.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll try and find some more sources on this as soon as I can go beyond the paywall to the research articles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Comment on the high pressure-experiments and Juno:&lt;/strong&gt; To my knowledge carbon-hydrogen mixtures are not being looked at in the labs, but this knowledge might also be flawed.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Juno will mostly be sensitive to Jupiter's density distribution at pressures up to ~1000 bars. Initial estimates show, that even if Jupiter has a dense, rocky core of 20 Earth masses, this will be barely visible in the data. To then filter out how much is carbon will be nigh-impossible with the current mission. &lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="543" LastEditDate="2017-01-23T00:07:23.973" LastActivityDate="2017-01-23T00:07:23.973" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9515" PostTypeId="2" ParentId="9484" CreationDate="2017-01-23T06:35:05.553" Score="1" Body="&lt;p&gt;You May think of this situation as following:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider an ocean-ocean divergent boundary and one of the oceanic plates (OP) is subducting below the continental plate (CP). Following shows such a setting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&amp;lt;----(OP)----|(MOR)|----(OP)----&gt;\\ &amp;lt;----CP----&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where, &#xA;OP= Oceanic Plate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;MOR&lt;/strong&gt;= Mid Oceanic Ridge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;CP&lt;/strong&gt;= Continental Plate&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;\&lt;/strong&gt; &lt;strong&gt;\&lt;/strong&gt; = shows subduction&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;--&gt;&lt;/strong&gt; direction of movement of plate&#xA;&lt;a href=&quot;https://i.stack.imgur.com/cG5rx.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cG5rx.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now think if the spreading ridge is coming closer to the CP. Which can be due to the difference in speed of motion of the CP. &#xA;One of such scenario is also illustrated in (&lt;a href=&quot;http://elibrary.bsu.az/azad/new/2194.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;book William Lowrie&lt;/a&gt;)&#xA;&lt;a href=&quot;https://i.stack.imgur.com/JcYdW.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JcYdW.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In such a scenario, though for a small duration, you can have such situation.&lt;/p&gt;&#xA;" OwnerUserId="5413" LastEditorUserId="5413" LastEditDate="2017-01-24T10:09:16.667" LastActivityDate="2017-01-24T10:09:16.667" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9517" PostTypeId="1" CreationDate="2017-01-23T13:57:14.427" Score="3" ViewCount="1210" Body="&lt;p&gt;I have heard that gold is found in the water coming out of glaciers in &lt;a href=&quot;https://www.linkedin.com/pulse/ranthak-valley-high-potential-prospect-gold-npakistan-yaqub-shah&quot; rel=&quot;nofollow noreferrer&quot;&gt;Skardu&lt;/a&gt; region of Pakistan. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given that this area is part of Himalaya, what processes could result into ores of gold in this area? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similar questions have been answered &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2393/why-do-gold-deposits-form-only-in-certain-areas-of-the-earth&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;https://earthscience.stackexchange.com/questions/391/in-what-geological-situations-can-i-find-gold/532#532&quot;&gt;here&lt;/a&gt; but I need more specific and detailed answers, considering the geology of this area. &lt;/p&gt;&#xA;" OwnerUserId="5557" LastEditorUserId="10810" LastEditDate="2017-08-30T07:02:08.937" LastActivityDate="2017-08-30T07:02:08.937" Title="How gold deposits can be formed in Himalayas?" Tags="|geology|mineralogy|minerals|economic-geology|mining|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9518" PostTypeId="2" ParentId="9389" CreationDate="2017-01-23T20:39:09.070" Score="2" Body="&lt;p&gt;Thunder is a manifestation of lightning, the sudden discharge of (static) electrical potential between cloud and ground, or cloud and cloud. That potential is built up through convection of vapor from low to high altitudes, typically tens of thousands of feet. Though possible in winter, though unusual, this kind of convection occurs mostly during summer months when extended sunshine bakes the earth surface, causing upward atmospheric movement of anything above.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastEditorUserId="7333" LastEditDate="2017-01-23T20:50:25.960" LastActivityDate="2017-01-23T20:50:25.960" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9519" PostTypeId="1" AcceptedAnswerId="9530" CreationDate="2017-01-24T02:00:12.357" Score="2" ViewCount="561" Body="&lt;p&gt;With the tornado outbreak in southern Georgia and northern/central Florida on Sunday that has tragically resulted in significant loss of life, eyes are once again on the weather. I was particularly impressed by the synoptic analysis done by the &lt;a href=&quot;https://www.washingtonpost.com/news/capital-weather-gang/wp/2017/01/23/inside-the-deadly-tornado-outbreak-that-struck-the-south/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Capital Weather Gang&lt;/a&gt; over at the Washington Post.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've always found this kind of mesoscale &quot;tale of the tape&quot; analysis to be interesting. Accuweather has made these kinds of analyses/maps, see &lt;a href=&quot;https://i.stack.imgur.com/sAcph.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;3/2/12&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to be able to look at upper-air and surface charts, and be able to explain the weather. How can I do that? What would I have to learn?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Through lots of studying of NWS upper air and surface charts, nullschool.net maps, and reading &lt;a href=&quot;http://cliffmass.blogspot.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cliff Mass's blog&lt;/a&gt;, I was able to draw some crude Microsoft Paint renditions of the basic summer weather pattern in the Pacific Northwest:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/73Qcr.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/73Qcr.png&quot; alt=&quot;PNW map 1&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UVNa9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UVNa9.png&quot; alt=&quot;PNW map 2&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, I was also to depict a map of the atmospheric conditions during the 4/27/2011 tornado outbreak, utilizing William Smith's &lt;a href=&quot;http://toweringcumulonimbus.blogspot.ca/2011/05/destruction-and-tragedy-in-dixie-april.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;excellent analysis&lt;/a&gt; (you'll want to click on the image for a larger resolution):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ByQME.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ByQME.png&quot; alt=&quot;4-27-11&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I want to learn how to do this on my own. I want to be able to look at charts, and use the charts to make an analysis of a weather event. I'll give you a good example of what I want to do:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During the early morning hours of July 7th, 1999, thunderstorms erupted over southwestern British Columbia and interior sections of WA near the Strait of Juan de Fuca. I know this because I lived through them, I was 7 years old at the time and they kept me up all night. NWS radar archives did not register any precipitation, but &lt;a href=&quot;http://vortex.plymouth.edu/cgi-bin/rad/gen-mdr-a.cgi?re=nw&amp;amp;va=all&amp;amp;yy=99&amp;amp;mm=07&amp;amp;dd=07&amp;amp;hh=09&amp;amp;ge=640x480&amp;amp;pg=web&quot; rel=&quot;nofollow noreferrer&quot;&gt;Plymouth State University's archives did&lt;/a&gt;. Plymouth State's archives also have upper-air analyses; the &lt;a href=&quot;http://vortex.plymouth.edu/cgi-bin/upa/gen-ctrmap-a.cgi?re=nw&amp;amp;le=500&amp;amp;va=hght&amp;amp;in=20&amp;amp;pl=cf&amp;amp;yy=1999&amp;amp;mm=07&amp;amp;dd=07&amp;amp;hh=00&amp;amp;sc=1.0&amp;amp;ge=1024x768&amp;amp;pg=web&quot; rel=&quot;nofollow noreferrer&quot;&gt;00Z 7 Jul 99 analysis&lt;/a&gt; shows the shortwave trough draped from the Puget Sound up to southern Vancouver Island. What I want to do is to learn how to forecast the weather at a basic level, then apply this knowledge and look at the upper air, mid-level, and surface analyses, then be able to put them all together to understand this event occurred. I then want to apply this knowledge to be able to predict or analyze other convective thunderstorm events or other major weather events. Other people have recommended reading the content at &lt;a href=&quot;http://theweatherprediction.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;theweatherprediction.com&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2017-01-25T15:25:16.743" Title="How can I learn to make mesoscale/synoptic analyses of major weather events?" Tags="|meteorology|weather-forecasting|severe-weather|mesoscale-meteorology|" AnswerCount="1" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="9520" PostTypeId="1" AcceptedAnswerId="9524" CreationDate="2017-01-24T06:56:28.873" Score="7" ViewCount="198" Body="&lt;p&gt;The false color image below shows synthetic aperture radar imaging from ESA's &lt;a href=&quot;http://esamultimedia.esa.int/docs/EarthObservation/Sentinel-1_sheet_March2016.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sentinel-1&lt;/a&gt; satellite. The map from the 20-Jan-2017 BBC article &lt;a href=&quot;http://www.bbc.com/news/science-environment-38686626&quot; rel=&quot;nofollow noreferrer&quot;&gt;Larsen ice crack continues to open up&lt;/a&gt; illustrates the same general area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Larson C Ice Shelf is the large blue-ish region in the middle of the false-color radar image, and is labeled as such. The crack is the thin lighter line just above the red arrow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Moving diagonally upwards to the right, the gray region is labeled &quot;Sea Ice&quot;. Is this just much thinner but mostly solid ice, or water with pieces of ice in it? While the ice shelf seems relatively uniform in tone, the gray sea ice area has a mottled pattern.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also the boundary between the two regions has what looks to me like some kind of 3D effect - the black, ribbon-like variable width region separating the two. Is this an effect of shadowing from oblique incidence? Is this actually the sidewall height of the ice shelf?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is also some discussion of radar imaging of sea ice in &lt;a href=&quot;https://earthscience.stackexchange.com/a/6821/6031&quot;&gt;this answer&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ONb9x.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ONb9x.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; Cropped and enlarged highlight from &lt;a href=&quot;http://esamultimedia.esa.int/docs/EarthObservation/Sentinel-1_sheet_March2016.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sentinel-1&lt;/a&gt; synthetic aperture radar image of the Larson C ice shelf, beginning of January 2017, found &lt;a href=&quot;http://www.rekanbola.com/patahan-gunung-es-di-antartika-terus-meluas/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. Image credit: ESA/EU/Copernicus&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OThoR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OThoR.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; &lt;a href=&quot;http://esamultimedia.esa.int/docs/EarthObservation/Sentinel-1_sheet_March2016.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sentinel-1&lt;/a&gt; synthetic aperture radar image of the Larson C ice shelf, beginning of January 2017, found &lt;a href=&quot;http://www.rekanbola.com/patahan-gunung-es-di-antartika-terus-meluas/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. Open in separate viewer or tab for full size. The width of the image is roughly 300km, south is towards the lower right. Image credit: ESA/EU/Copernicus&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2bSRB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2bSRB.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; Map of the region around the Larson C ice shelf, beginning of January 2017, from &lt;a href=&quot;http://www.bbc.com/news/science-environment-38686626&quot; rel=&quot;nofollow noreferrer&quot;&gt;BBC here&lt;/a&gt;. Image credit: MIDAS Project, A. Luckman, Swansea University. Because it's difficult to read, I'll point out that Wales not shown in it's correct location - it's there for scale only.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="11908" LastEditDate="2019-03-13T05:16:30.620" LastActivityDate="2019-03-13T05:16:30.620" Title="Need help understanding this satellite image of Larson C ice shelf" Tags="|glaciology|remote-sensing|sea-ice|ice-shelf|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9521" PostTypeId="1" AcceptedAnswerId="9522" CreationDate="2017-01-24T10:12:54.330" Score="19" ViewCount="7313" Body="&lt;p&gt;I recently saw a short video from NASA. It shows the moon passing by the Earth as it rotates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nasa.gov/sites/default/files/styles/full_width/public/thumbnails/image/dscovrepicmoontransitfull.gif&quot;&gt;&lt;img src=&quot;https://www.nasa.gov/sites/default/files/styles/full_width/public/thumbnails/image/dscovrepicmoontransitfull.gif&quot; alt=&quot;NASA 360 degree view of Earth&quot;&gt;&lt;/a&gt;&#xA;NASA link: &lt;a href=&quot;https://www.nasa.gov/feature/goddard/from-a-million-miles-away-nasa-camera-shows-moon-crossing-face-of-earth&quot;&gt;From a Million Miles Away, NASA Camera Shows Moon Crossing Face of Earth&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The video itself looks quite fake, but that can probably be attributed to the fact that it was reconstructed from sensor data as opposed to a regular camera.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is, why do the clouds not appear to move at all? According to the website, the images span approximately 5 hours.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are a lot of people online saying the video is fake. I believe the Earth is a globe, but I can see why people have their doubts about this particular video.&lt;/p&gt;&#xA;" OwnerUserId="7348" LastEditorUserId="11908" LastEditDate="2018-04-12T17:48:22.637" LastActivityDate="2018-08-17T22:39:09.427" Title="Why clouds are not moving in NASA's video of the Moon passing in front of the Earth?" Tags="|clouds|remote-sensing|earth-rotation|astronomy|" AnswerCount="3" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="9522" PostTypeId="2" ParentId="9521" CreationDate="2017-01-24T10:28:59.007" Score="26" Body="&lt;p&gt;They are moving, but not fast enough to notice at the distance shown.  From the NASA page:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;These images were taken between 3:50 p.m. and 8:45 p.m. EDT on July 16, showing the moon moving over the Pacific Ocean near North America. The North Pole is in the upper left corner of the image, reflecting the orbital tilt of Earth from the vantage point of the spacecraft.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In five hours, clouds may move some hundreds of kilometers at most.  The half-disk of the Earth is nearly 13,000 km across, so over the period the pictures were taken, the clouds should only be expected to move a small fraction of the width of the disk.&lt;sup&gt;[1]&lt;/sup&gt;  Add to that the fact that the Earth is rotating and it is not readily apparent that they move at all.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt;: Say the clouds in a huge hurricane move in a straight line at 100km/hr; over this 5-hour animation, that's 500 km movement which is just under 4% of the Earth's &lt;a href=&quot;https://www.google.com/search?q=diameter+of+the+earth+in+km&quot; rel=&quot;noreferrer&quot;&gt;12,742 km diameter&lt;/a&gt;. The Earth is about 550px in this image and 550 × .04 = 22 pixels maximum change.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="725" LastEditDate="2017-01-26T21:33:28.727" LastActivityDate="2017-01-26T21:33:28.727" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9523" PostTypeId="2" ParentId="9509" CreationDate="2017-01-24T12:45:51.517" Score="3" Body="&lt;p&gt;1 in 100,000 is an estimate of frequency based on past eruptions which should not be confused with possbility or probability.  It is an oversimplification to state the probability of an eruption as 0.001% chance per year.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-01-24T12:45:51.517" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9524" PostTypeId="2" ParentId="9520" CreationDate="2017-01-24T13:29:27.990" Score="6" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/TTPyN.jpg&quot; alt=&quot;natural-color&quot;&gt;&#xA;I found a natural-color image of the same area: 68.28 South, 60.47 East, North is up, resolution is 130m/px, which makes the whole image about 100 km x 100 km. Looking at the image i'd say that:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;sea ice is water with pieces of ice in it,&lt;/li&gt;&#xA;&lt;li&gt;the boundary between the two regions is clear water, probably caused by winds and currents moving the floating ice away from the edge of the ice shelf.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I got the image at &lt;a href=&quot;http://apps.sentinel-hub.com/sentinel-playground/#lat=-68.10712566634318/lng=-60.3424072265625/zoom=9/preset=1_NATURAL_COLOR/layers=B04,B03,B02/maxcc=100/gain=0.3/time=2015-01-01|2016-11-21&quot;&gt;Sentinel Playground&lt;/a&gt; using 100% cloud filter, 0.3 gain and date selection of 2016-11-21.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: Added more info about the position, scale and orientation of the image.&lt;/p&gt;&#xA;" OwnerUserId="7350" LastEditorUserId="7350" LastEditDate="2017-01-24T14:27:16.347" LastActivityDate="2017-01-24T14:27:16.347" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="9525" PostTypeId="2" ParentId="9521" CreationDate="2017-01-24T17:31:38.543" Score="29" Body="&lt;p&gt;The clouds can be seen moving but of course it's subtle at first glance.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Frame 16:&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1PkMa.gif&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1PkMa.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Frame 20:&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/couWJ.gif&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/couWJ.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7354" LastActivityDate="2017-01-24T17:31:38.543" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9526" PostTypeId="1" CreationDate="2017-01-24T20:26:53.620" Score="6" ViewCount="545" Body="&lt;p&gt;Imagine I want to make a floating wind turbine like the &lt;a href=&quot;http://www.altaerosenergies.com/index.html&quot;&gt;Altaeros BAT&lt;/a&gt;, which is tethered and uses helium. What would be the best height to keep such a device deployed? I know that wind velocity decreases near the ground due to friction with the Earth's surface. Though, the density of air decreases with height, so the force of high winds aloft are lessened.  Considering these issues, at what altitudes do the winds exert the most force for a tethered wind turbine to produce the most energy?  Please disregard the energy required to keep the turbine afloat.&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="543" LastEditDate="2017-01-25T02:43:45.033" LastActivityDate="2017-01-25T22:37:47.087" Title="At what altitude do winds exert the most force?" Tags="|atmosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9527" PostTypeId="1" CreationDate="2017-01-25T11:09:02.850" Score="2" ViewCount="413" Body="&lt;p&gt;Global forecast systems(GFS)  gives analysis and forecasts at different time steps. Their main source of input is upper air data which is recorded only twice in a day(observation comes at 00 and 12). But analysis step which incorporates the observations is done at 00,06,12,18 hrs. How is that ?Is my basic understanding understanding completely wrong?&lt;/p&gt;&#xA;" OwnerUserId="5482" LastActivityDate="2017-01-25T16:17:11.273" Title="upper air data(observation) and analysis step for GFS model" Tags="|weather-forecasting|data-analysis|gfs|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9528" PostTypeId="1" CreationDate="2017-01-25T12:40:49.617" Score="6" ViewCount="297" Body="&lt;p&gt;Sometimes you read about skin cancer and the ozone hole in Australia.&#xA;But when you look it up the ozone hole is basically just near the South Pole, and maybe a bit above the North Pole (because that’s where it’s really cold).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But has the rest of the world even been really affected? Looking at this &lt;a href=&quot;https://svs.gsfc.nasa.gov/vis/a030000/a030600/a030602/ozone_hole_recovery.v2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA graphic&lt;/a&gt; it doesn’t seem there were significant changes for most people.  Perhaps the average ozone levels in Europe or Australia even increased?&lt;/p&gt;&#xA;" OwnerUserId="7365" LastEditorUserId="6298" LastEditDate="2017-02-11T10:23:42.977" LastActivityDate="2017-02-11T10:23:42.977" Title="Does the Antarctic Ozone Hole affect the rest of the world?" Tags="|atmosphere|antarctic|ozone|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="9529" PostTypeId="2" ParentId="9517" CreationDate="2017-01-25T13:08:42.127" Score="2" Body="&lt;p&gt;Himalayas represent a huge area with a complex geological history which I suspect has large areas that have never been adequately mapped to allow for an ore deposit evaluation. Nevertheless, placer gold might be found within any region of the  Himalayas.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Placer gold deposits are an accumulation of gold formed by gravity separation during sedimentary processes of the gold bearing host rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reference: &lt;a href=&quot;https://www.britannica.com/science/placer-deposit&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.britannica.com/science/placer-deposit&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many granite bearing mountains containing quartz-feldspar porphyry dykes/veins associated with elevated concentrations of sulfur and arsenic can be found  in many parts of the world. I would assume these deposits would also found in the Himalayas. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reference: &lt;a href=&quot;http://www.minelinks.com/alluvial/goldDeposits.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.minelinks.com/alluvial/goldDeposits.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-01-25T13:08:42.127" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9530" PostTypeId="2" ParentId="9519" CreationDate="2017-01-25T15:08:45.173" Score="1" Body="&lt;p&gt;You're definitely on the right path with wanting to dig into raw data yourself.  &lt;a href=&quot;http://weather.rap.ucar.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;RAP&lt;/a&gt; has always been a pretty solid source of useful basic data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But in terms of making sense of the data, it indeed will take some practice. You can feel like you're not getting it at all, but suddenly pieces will start to click, much like riding a bike.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically, you need to start building from those that know these things.  As such, one good insight can be in reading NWS forecast discussions, which you can find among the rich data at &lt;a href=&quot;http://kamala.cod.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;kamala.cod.edu&lt;/a&gt; or in one big set at &lt;a href=&quot;http://forecast.weather.gov/product_sites.php?site=NWS&amp;amp;product=AFD&quot; rel=&quot;nofollow noreferrer&quot;&gt;this NWS link&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But, at least in terms of storms, I think the place to start has to be the same place that the CWG article relied upon: the &lt;a href=&quot;http://www.spc.noaa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Storm Prediction Center&lt;/a&gt;.  Specifically:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.spc.noaa.gov/products/outlook/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Convective outlooks&lt;/a&gt; will explain the day's weather picture and large key features&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.spc.noaa.gov/products/md/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mesoscale discussions&lt;/a&gt; offer insight into the finer details that make all the difference, ones which even the most seasoned meteorologists may not always recognize.&lt;/li&gt;&#xA;&lt;li&gt;Then the &lt;a href=&quot;http://www.spc.noaa.gov/exper/mesoanalysis/&quot; rel=&quot;nofollow noreferrer&quot;&gt;mesoanalysis tool&lt;/a&gt; allows you to dig more into the data yourself and see overlays of a deep variety of parameters.  But the tool that may be right down your alley may be the &lt;a href=&quot;http://www.spc.noaa.gov/exper/compmap/&quot; rel=&quot;nofollow noreferrer&quot;&gt;composite map generator tool&lt;/a&gt;, which allows you to combine just the noteworthy parts of the key elements onto one image and see how they line up.&lt;/li&gt;&#xA;&lt;li&gt;And then the &lt;a href=&quot;http://www.spc.noaa.gov/exper/archive/events/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Severe Weather Events Archive&lt;/a&gt; allows you to dig into a great deal of past events, and the &lt;a href=&quot;http://www.spc.noaa.gov/exper/outbreaks/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Outbreaks Browser&lt;/a&gt; lets you see the bigger events in a very sharp, graphical way.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;And there's plenty of other great things there too; climatologies, publications, education pages, etc.  Now, obviously the majority of this information focuses most directly on severe weather setups (though the SPC does actually also issue winter weather mesoscale discussions [the WPC now does &lt;a href=&quot;http://www.wpc.ncep.noaa.gov/metwatch/metwatch_mpd.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;heavy rain MDs&lt;/a&gt;, and of course the &lt;a href=&quot;http://www.nhc.noaa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NHC&lt;/a&gt; does the main discussions on tropical systems]), and only regard US events.  But these tools can really help even those interested more in other areas and topics get a better understanding of the bigger picture, which sync up well into just about every topic of synoptic and mesoscale meteorology, regardless of location.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, in terms of helping you personally narrow down onto the key elements, so that you could make your own composite map... the &lt;a href=&quot;http://www.srh.noaa.gov/jetstream/tstorms/ingredient.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;classic ingredients necessary for thunderstorms&lt;/a&gt; &lt;sup&gt;&lt;sub&gt;(also see &lt;a href=&quot;http://www.theweatherprediction.com/habyhints/141/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;)&lt;/sub&gt;&lt;/sup&gt; can be a good starting point:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Instability... the predisposition of rising air to continue rising.  Basically warm (and moist) surface air and anomalously cold air aloft.&lt;/li&gt;&#xA;&lt;li&gt;Moisture... high dewpoints create clouds more readily, form them at lower heights (important for tornadoes), and produce more precipitation/energy for storms.  Plus it helps the instability.&lt;/li&gt;&#xA;&lt;li&gt;Trigger... something to get the air moving to rise so that the ingredients can be realized.  There are a WIDE range of possibilities here.  Important ones for storms include &lt;a href=&quot;http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/af/frnts/home.rxml&quot; rel=&quot;nofollow noreferrer&quot;&gt;fronts&lt;/a&gt;, the &lt;a href=&quot;http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/af/frnts/dfdef.rxml&quot; rel=&quot;nofollow noreferrer&quot;&gt;dryline&lt;/a&gt;, vorticity advection aloft (incoming vort maxes you see spinning around on &lt;a href=&quot;http://rammb.cira.colostate.edu/ramsdis/online/loop.asp?data_folder=goes-west_goes-east/goes-east_16km_psir3&amp;amp;width=640&amp;amp;height=480&quot; rel=&quot;nofollow noreferrer&quot;&gt;water vapor imagery&lt;/a&gt;), &lt;a href=&quot;http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/cyc/upa/vrt.rxml&quot; rel=&quot;nofollow noreferrer&quot;&gt;favorable jet streak quadrants&lt;/a&gt;, strong temperature advection (e.g. &lt;a href=&quot;https://www.youtube.com/watch?v=DjU0ko41_a4&quot; rel=&quot;nofollow noreferrer&quot;&gt;low-level jets&lt;/a&gt;), &lt;a href=&quot;http://lukemweather.blogspot.com/2011/06/storms-firing-on-outflow-boundary.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;outflow boundaries&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Sea_breeze&quot; rel=&quot;nofollow noreferrer&quot;&gt;seabreezes/lakebreezes/riverbreezes&lt;/a&gt;, &lt;a href=&quot;http://www.spc.noaa.gov/coolimg/gwavecb.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;gravity waves&lt;/a&gt;, &lt;a href=&quot;http://theweatherforums.com/archive/index.php?/topic/15745-diffluence-and-divergence/&quot; rel=&quot;nofollow noreferrer&quot;&gt;diffluence aloft&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Orographic_lift&quot; rel=&quot;nofollow noreferrer&quot;&gt;terrain/orographic lift&lt;/a&gt;, &lt;a href=&quot;http://tornado.sfsu.edu/Geosciences/classes/m835/Cases/HCR/HCR.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;horizontal convection rolls/cloud streets&lt;/a&gt;, &lt;a href=&quot;http://www.theweatherprediction.com/habyhints/116/&quot; rel=&quot;nofollow noreferrer&quot;&gt;isentropic upglide&lt;/a&gt;, and &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0493(1998)126%3C2117%3ASMPDTP%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;differential heating boundaries&lt;/a&gt;.  Suffice to say there are a lot of options in play, though some are more common than others.  But you'd be surprised how quickly you can get used to finding them with practice.  (And it's really a pity there isn't greater information/graphics/videos/explanations on some of those topics... perhaps some of these will eventually work their way here to be questions that can encourage a better, clearer reference to form)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;And finally, to really ramp up severe weather, and also primary to tornado threat, you add in ingredient four...&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;4&quot;&gt;&#xA;&lt;li&gt;Wind shear... different winds at different height.  A combination of how much directional difference there is and how much speed difference.  Significantly impacted by upper level jet streaks, low-level jets, and the direction of the surface flow is.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;This may sound like a ton.  But taking a second look at that Accuweather graphic, it's those same ingredients:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/iJyxc.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iJyxc.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So with those basics to start at, the pictures have a pattern to them.  And then when you add in the finer details discussed, you can really find the deeper things you won't on the more basic composites.  You can see what really DID make all the difference.  In the end, it's an investigative science, a continual game of making and refining theories, and it's something you only get better at with practice.  Even top meteorologists still don't always have the answers; I don't know whether anyone has come up with a perfect explanation yet for why the supercells on Sunday in Central Florida didn't produce prolific tornadoes.  Forecasts do still fail.  And so we're always trying to better clear up the details of each past event, so that we'll be better at the next one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A couple final links... it seems like &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0434(1986)001%3C0164:STFAHP%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;this journal article&lt;/a&gt; might be fairly interesting and approachable for you... and then websites like &lt;a href=&quot;http://www.stormtrack.org&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stormtrack&lt;/a&gt; can be a really great asset, as that's where quite a few chasers/meteorologists often congregate to discuss big weather events.  The more time you spend looking at this stuff, engaging in conversation, challenging the reasoning you/others have, and learning, the better you'll be able to form a clearer picture of what's going on.  A much better picture than any news article will ever give!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-01-25T15:25:16.743" LastActivityDate="2017-01-25T15:25:16.743" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="9531" PostTypeId="2" ParentId="9527" CreationDate="2017-01-25T16:09:18.927" Score="1" Body="&lt;p&gt;You are right that upper air soundings are typically only done twice a day, and even at quite a coarse observation spacing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And that upper air data is definitely very important in models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd suggest that, firstly, it's important to note that &lt;strong&gt;even a broad, very hazy picture aloft really helps a great deal at the surface&lt;/strong&gt;.  That can be seen in the &lt;a href=&quot;http://www.theweatherprediction.com/habyhints/255/&quot; rel=&quot;nofollow noreferrer&quot;&gt;quasigeostrophic omega equation&lt;/a&gt;.  Basically the large-scale highs and lows and jet streaks drive much of the vertical air motion in the atmosphere.  Plus there aren't quite as many complexities caused by terrain/ground cover/moisture/differential heating that the surface layer sees.&#xA;So because the evolution of those large-scale features is pretty straightforward over the course of a day, the early morning's upper-level forecast is still quite reliable and helpful 6 hours later.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But that said, smaller scale shortwaves and vorticity maxima are absolutely vital to weather forecasting too.  And with smaller size and more transient nature, neglecting their changes over 6 hours is likely to really harm forecasts when it comes to critical subtle differences such as you'd see in a tornado outbreak or hurricane track.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So indeed, how &lt;em&gt;DO&lt;/em&gt; we recognize those changes?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Well, we do have a second source that these days is probably at least as important as soundings, perhaps even moreso - &lt;strong&gt;satellite imagery&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See for example &lt;a href=&quot;http://www.ssd.noaa.gov/goes/east/tatl/h5-loop-vis.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; satellite page.  You can turn on HDW-low, HDW-mid, HDW-high.  As far as I understand it, the models are ingesting that information readily (and likewise cloud coverage, which are just as important).  I believe some satellites also have vertical temperature sounders that are used more now as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And third, &lt;strong&gt;we also have some other data sources that help&lt;/strong&gt;.&#xA;In certain parts of the world, we've got radars.  I believe at least some of the better models these days are using that data... there's plenty of wind data to be had from velocities (though it would seem challenging to use/analyze it given things like range-folded velocities and the ambiguity of tangential winds &lt;a href=&quot;http://www.nat-hazards-earth-syst-sci.net/6/285/2006/nhess-6-285-2006.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;see the intro to [this article]&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plus, I believe at least the ECMWF has had real success in ingesting &lt;a href=&quot;https://amdar.noaa.gov/FAQ.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ACARS&lt;/a&gt;... atmospheric data that are generally reported by all commercial aircraft.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But... all that said, your point still has some real potency.  Especially when we note that, when it comes to our best model, the ECMWF... it still only runs twice a day.  Maybe other reasons drive the decision, but you'd think they still weigh how improved such forecasts are.  So it seems fairly likely that they've determined that long-range forecasts don't improve much when they are still based heavily upon that older information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But then, I think everyone would agree that having hourly models available like the HRRR is very useful in important nowcasting situations, such as severe weather awareness.  So maybe the overlooked small data changes are (counterintuitively?) more important to long-range forecasting than short-term.  Definitely an interesting question you've raised!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-01-25T16:17:11.273" LastActivityDate="2017-01-25T16:17:11.273" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9532" PostTypeId="1" AcceptedAnswerId="9537" CreationDate="2017-01-25T17:17:32.563" Score="7" ViewCount="1592" Body="&lt;p&gt;In ocean spectra such as the Pierson Moskowitz or the JONSWAP models, the units of $S(\omega)$ are $m^2/(rad/s)$ (or whatever unit of measurement you are working in). Where does the $m^2$ come from and what does it mean physically?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand that the integral of the spectrum over all frequencies, i.e. $\int S(\omega) \,d\omega $, is the variance which means that the integral should have $m^2$ units? Please correct me if I am wrong.&lt;/p&gt;&#xA;" OwnerUserId="7367" LastEditorUserId="7367" LastEditDate="2017-01-27T19:08:10.377" LastActivityDate="2017-01-27T19:08:10.377" Title="Units of wave spectrum" Tags="|oceanography|models|waves|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9533" PostTypeId="1" AcceptedAnswerId="9534" CreationDate="2017-01-25T18:08:12.123" Score="5" ViewCount="3163" Body="&lt;p&gt;I know that the moon has lunar regolith and earth has earth soil, but what is the difference between them?&lt;/p&gt;&#xA;" OwnerUserId="6784" LastEditorUserId="595" LastEditDate="2018-12-06T16:22:41.547" LastActivityDate="2018-12-06T16:22:41.547" Title="What is the difference between lunar and earth soil" Tags="|soil|moon|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="9534" PostTypeId="2" ParentId="9533" CreationDate="2017-01-25T22:14:35.430" Score="5" Body="&lt;p&gt;The single biggest difference is the lack of chemical weathering in lunar soils which are subject to physical weathering almost exclusively. If you exclude biological processes, terrestrial rocks undergo significant weathering from water and atmosphere, which the moon lacks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, both earth and moon contain feldspar-rich rocks, however, clays, the result of chemically altered feldspars, are not found on the moon. Neither are oxidized minerals, as the moon has no oxygen-rich atmosphere to speak of.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-01-25T22:14:35.430" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9535" PostTypeId="2" ParentId="9526" CreationDate="2017-01-25T22:29:04.377" Score="1" Body="&lt;p&gt;&quot;.....the density of air decreases with height, so the force of high winds aloft are lessened.&quot; I can personally vouch for the difference between a 60mph wind at sea level, and one at 14,000 feet! However, however, the single biggest difference between the two altitudes isn't so much the force of that wind, but the consistency of that wind speed, which seems to matter most to wind generation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's how a wind turbine engineer would think of this problem:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From The Engineer's Toolbox- &lt;a href=&quot;http://www.engineeringtoolbox.com/wind-power-d_1214.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Power generated from the wind&lt;/strong&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Theoretically power in moving air - or wind - can be calculated&lt;/p&gt;&#xA;&#xA;&lt;p&gt;P = 1/2 ρ A v^3&lt;br&gt;&#xA;  =  1/8 ρ π d^2 v^3     &lt;/p&gt;&#xA;&#xA;&lt;p&gt;where&#xA;&lt;em&gt;P = power (W)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;ρ = density of air (kg/m3)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;A = wind mill area perpendicular to the wind (m2)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;v = wind velocity (m/s)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;π = 3.14....&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;d = wind mill diameter (m)&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="7333" LastEditorUserId="7333" LastEditDate="2017-01-25T22:37:47.087" LastActivityDate="2017-01-25T22:37:47.087" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9536" PostTypeId="1" AcceptedAnswerId="9546" CreationDate="2017-01-26T05:56:14.180" Score="3" ViewCount="1598" Body="&lt;p&gt;We often read that El Nino and La Niña occur alternatively. Are they the exact opposite of each other? Or, in other words, can they happen at the same time? (i.e. the whole Pacific Ocean has a higher temperature than normal).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If so, what is the common name of them?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="595" LastEditDate="2017-01-27T10:48:01.500" LastActivityDate="2017-01-27T16:22:18.253" Title="Can El Niño and La Niña occur at the same time?" Tags="|climate|enso|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9537" PostTypeId="2" ParentId="9532" CreationDate="2017-01-26T14:23:10.413" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;I understand that the integral of the spectrum over all frequencies is the variance which means that the integral should have $m^2$ units? Please correct me if I am wrong.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You are correct. If elevation $\eta(t)$ is the measured quantity (units of $m$), the Fourier transform of wave variance $\eta^2$ yields spectrum $S(f)$ with the units of $m^2/Hz$, or if you are working with angular frequency $\omega = 2\pi f$, it yields $S(\omega)$ with the units of $m^2/rad/Hz$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More details can be found in the answer to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4521/is-wave-spectrum-always-positive-and-why/4522&quot;&gt;this question&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="192" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2017-01-26T14:23:10.413" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9539" PostTypeId="2" ParentId="9347" CreationDate="2017-01-26T15:57:59.380" Score="3" Body="&lt;p&gt;What you're really looking at is a &lt;a href=&quot;http://dnr.wi.gov/education/documents/groundwater/QuantitativeExercise.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;fairly basic groundwater flow problem&lt;/a&gt;. What you need are &lt;a href=&quot;http://www.geotechdata.info/parameter/permeability.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;hydraulic conductivity values&lt;/a&gt; for the &quot;gravel&quot; sediment in question. Given the fixed 1% grade, what you want to find is the &quot;tank&quot; length that maximizes pollutant residence time, and is relatively easy to calculate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I believe that this is the basic design around which your illustration comes from:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sswm.info/category/implementation-tools/wastewater-treatment/hardware/semi-centralised-wastewater-treatments/h&quot; rel=&quot;nofollow noreferrer&quot;&gt;Horizontal Subsurface Flow CW&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know how you're going to solve the problem of finding and keeping enough water in your system during the dry season. You're system depends on growing plants!&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-01-26T15:57:59.380" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9540" PostTypeId="1" AcceptedAnswerId="9545" CreationDate="2017-01-27T06:17:02.000" Score="6" ViewCount="3717" Body="&lt;p&gt;I've noticed that some ‘highest‘  high tides in one month are bigger than the highest high-tide of previous months. Why is this so? &lt;/p&gt;&#xA;" OwnerUserId="7380" LastEditorUserId="7380" LastEditDate="2019-08-31T20:43:24.660" LastActivityDate="2019-08-31T21:15:58.430" Title="Why do high tides vary month to month?" Tags="|oceanography|sea-level|tides|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="9542" PostTypeId="1" CreationDate="2017-01-27T11:31:55.907" Score="3" ViewCount="1205" Body="&lt;p&gt;The Earth's moon is in synchronous rotation around Earth. The question: Why are there craters on the lit side of the moon and the dark and of which are not parallel with crater schemes on Earth?&lt;/p&gt;&#xA;" OwnerDisplayName="user7384" LastEditorDisplayName="user7384" LastEditDate="2017-01-27T15:14:35.413" LastActivityDate="2017-02-06T19:18:43.440" Title="Why are there craters on the moon?" Tags="|mineralogy|meteorite|moon|earth-moon|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9543" PostTypeId="1" AcceptedAnswerId="9548" CreationDate="2017-01-27T14:03:37.240" Score="1" ViewCount="146" Body="&lt;p&gt;As one half of the naturally occurring &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonate%E2%80%93silicate_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;Carbonate–silicate cycle&lt;/a&gt;, carbon dioxide is naturally removed from the atmosphere by the chemical reaction:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;CaSiO$_3$ + 2CO$_2$ + H$_2$O → Ca2+(aq) + 2HCO$_3$-(aq) + SiO$_2$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would be the side effects of artificially enhancing this process by mining large amounts (on the order of 10 times world coal production) of silicate bearing rocks to reverse man-made climate change?&lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2017-01-27T17:30:56.737" Title="What negative side effects would occur if silicate mining were used to artificially lower atmospheric CO2 concentrations?" Tags="|atmosphere|climate-change|geochemistry|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9544" PostTypeId="1" CreationDate="2017-01-27T14:26:46.523" Score="5" ViewCount="12477" Body="&lt;p&gt;Assume we have a mountain landscape without trees.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would it be less windy in a valley than on a hill, or would the wind just be the same? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or in other words, which of the two images below describe the wind more accurately:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ed5BN.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ed5BN.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7387" LastEditorUserId="6643" LastEditDate="2017-03-01T10:10:49.163" LastActivityDate="2021-09-15T04:34:09.710" Title="Is it less windy in a valley than on a hill?" Tags="|wind|planetary-boundary-layer|" AnswerCount="3" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="9545" PostTypeId="2" ParentId="9540" CreationDate="2017-01-27T14:51:46.960" Score="9" Body="&lt;p&gt;The dynamics of the tides are quite complex. The main idea is that gravity from the Moon and the Sun affect water (and everything else) on Earth. The issue is that there are several motions that alter the distance between the 3 systems and those motions cause interactions between the different frequencies involved. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Theory_of_tides&quot; rel=&quot;nofollow noreferrer&quot;&gt;Equilibrium Theory of Tides&lt;/a&gt; separates the different effects into a set of constituents by conducting a harmonic analysis. The relevant periods are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the lunar day (period of lunar rotation), 24.84 mean solar hours.&lt;/li&gt;&#xA;&lt;li&gt;the &lt;a href=&quot;https://en.wikipedia.org/wiki/Orbit_of_the_Moon&quot; rel=&quot;nofollow noreferrer&quot;&gt;sidereal month&lt;/a&gt; (period of lunar declination), 27.32 mean solar days.      &lt;/li&gt;&#xA;&lt;li&gt;the &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_year&quot; rel=&quot;nofollow noreferrer&quot;&gt;tropical year&lt;/a&gt; (period of &lt;a href=&quot;https://en.wikipedia.org/wiki/Position_of_the_Sun#Declination_of_the_Sun_as_seen_from_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;solar declination&lt;/a&gt;), 365.24 mean solar days.&lt;/li&gt;&#xA;&lt;li&gt;the period of the lunar perigee, 8.85 years (1 year = 365.2421988 days).&lt;/li&gt;&#xA;&lt;li&gt;the period of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Lunar_node&quot; rel=&quot;nofollow noreferrer&quot;&gt;lunar node&lt;/a&gt;, 18.61 years.&lt;/li&gt;&#xA;&lt;li&gt;the period of the solar perihelion, 20940 years.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The explanation of each constituent can be rather complex (&lt;a href=&quot;https://earthscience.stackexchange.com/questions/8407/definitions-of-tidal-harmonic-constituents&quot;&gt;some examples in this other answer&lt;/a&gt;). The different amplitudes in a day and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Tide#Range_variation:_springs_and_neaps&quot; rel=&quot;nofollow noreferrer&quot;&gt;spring-neap cycle&lt;/a&gt; are related to the combination of the main lunar and solar effects. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The differences in high/low tide from month to month are related to the next two main frequencies of oscillation. Mainly, the variations in Earth-Sun distance associated occurring in a period of &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_year&quot; rel=&quot;nofollow noreferrer&quot;&gt;tropical year&lt;/a&gt;. The lunar distance also contributes to these differences, but its cycle is much longer (~9 years). Also, the spring-neap cycle (with a frequency of half a lunar month ~13.5 days) will occur at different times of the month and can lead to differences in tidal amplitude if you compare the tides measured the same day of consecutive months.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/yvFmm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yvFmm.jpg&quot; alt=&quot;spring-neap tide from www.niwa.co.nz&quot;&gt;&lt;/a&gt;&#xA;(Source www.niwa.co.nz)&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2017-01-29T15:37:19.400" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9546" PostTypeId="2" ParentId="9536" CreationDate="2017-01-27T16:22:18.253" Score="2" Body="&lt;p&gt;By definition, El Niño and La Niña cannot occur at the same time. They are instead opposite extreme phases of the El Niño Southern Oscillation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;El Niño conditions occur when the average temperature of the Niño 3.4 region is a half degree or more over the average for three consecutive months or more. La Niña conditions occur when the average temperature is a half degree or more below the average for three consecutive months or more. The reason for looking at a rather narrow band of the equatorial Pacific rather than looking at the Pacific as a whole is because of teleconnections. Whether El Niño, neutral, or La Niña conditions apply has wide ranging impacts across the globe.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-01-27T16:22:18.253" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9548" PostTypeId="2" ParentId="9543" CreationDate="2017-01-27T17:30:56.737" Score="3" Body="&lt;p&gt;A review article on the subject in the AGU journal &lt;a href=&quot;http://agupubs.onlinelibrary.wiley.com/hub/journal/10.1002/(ISSN)1944-9208/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reviews of Geophysics&lt;/a&gt; &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/rog.20004/pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Enhanced chemical weathering as a geoengineering strategy to reduce atmospheric carbon dioxide, supply nutrients, and mitigate ocean acidification&lt;/a&gt; by Hartmann, et.al. (2013) notes many uncertainties that would need to be researched and quantified to evaluate both the potential effectiveness as well as the drawbacks of the process, known as Enhanced Weathering:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;The potential negative environmental impact of Enhanced Weathering is&#xA;  also important to consider and investigate further. Application of&#xA;  rock powder to the land surface might increase the concentration of&#xA;  airborne dust in the local environment. The potential risk to human&#xA;  and animal health may limit the appropriate application sites (away&#xA;  from human centres or sensitive ecosystems) or the severity of&#xA;  comminution, depending on the techniques applied. This in turn will&#xA;  limit the efficacy and effectiveness of Enhanced Weathering. The&#xA;  mobilization of potentially toxic elements contained in some silicate&#xA;  rocks may detrimentally effect primary production and/or accumulate in&#xA;  the food chain, both of which could be harmful to human populations.&#xA;  Therefore an assessment of usable rocks and their locations is&#xA;  needed.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Also:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;To sequester a significant amount of carbon dioxide from the&#xA;  atmosphere, an Enhanced Weathering program would need to process 1Gt&#xA;  to 10 s of Gt of rock per year. This would make it one of the largest&#xA;  global industries.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That alone would create economic and social impacts, as well as additional carbon emissions that would need to be offset.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2017-01-27T17:30:56.737" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9549" PostTypeId="1" CreationDate="2017-01-27T18:14:00.770" Score="3" ViewCount="234" Body="&lt;p&gt;In the mantle, minerals contained in buoyant plumes of rock undergo phase changes from solid to liquid (decompression melting). In the atmosphere, waters contained in buoyant plumes of air undergo phase changes from gas to liquid (clouds and precipitation). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plumes in both systems experience decreasing pressure and decreasing temperature as they rise.  Why do the phase changes go in opposite directions, i.e. why do rising mantle minerals melt while rising atmospheric waters condense?&lt;/p&gt;&#xA;" OwnerUserId="7389" LastActivityDate="2017-02-27T20:39:05.010" Title="Why do buoyantly rising mantle minerals melt, yet buoyantly rising atmospheric waters condense?" Tags="|geophysics|atmosphere|mineralogy|mantle|thermodynamics|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9550" PostTypeId="1" AcceptedAnswerId="9558" CreationDate="2017-01-27T19:29:58.247" Score="5" ViewCount="882" Body="&lt;p&gt;I am considering earth's internal heat budget for a project in university. For this I need an estimate on the temperature of the earth shortly after it had formed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Kelvin's &lt;a href=&quot;https://www.google.de/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=&amp;amp;ved=0ahUKEwiT8b_ShePRAhUCECwKHXymAP0QFggtMAI&amp;amp;url=http%3A%2F%2Fwww.es.ucsc.edu%2F~pkoch%2FEART_206%2F09-0108%2FKelvin%25201862%2520TRSE.pdf&amp;amp;usg=AFQjCNFV8qxfHAs3hkX9HmBa4I76QsyXag&amp;amp;sig2=HHIPNonFF6rFB1gUXnTWNg&amp;amp;cad=rja&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;On the Secular cooling of the Earth&lt;/em&gt;&lt;/a&gt; he estimates the earth's temperature to be around 3800°C initially. This seems to get cited a lot but I have a hard time securing sources for why this value is a logical guess. Any help is appreciated.&lt;/p&gt;&#xA;" OwnerUserId="7390" LastEditorUserId="87" LastEditDate="2017-01-28T10:19:49.383" LastActivityDate="2017-01-30T03:39:30.123" Title="Surface temperature in early hadean period" Tags="|geophysics|temperature|earth-history|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9551" PostTypeId="2" ParentId="9542" CreationDate="2017-01-27T20:12:31.370" Score="4" Body="&lt;p&gt;There are craters on the Earth, Arizona's Meteor Crater being perhaps the best-known example.  The reason that there aren't a lot more (obvious) ones is that the Earth has lots of dynamic processes, ranging from weather to plate tectonics, that gradually erase them.  The Moon doesn't have these things, so craters last for billions of years.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2017-01-27T20:12:31.370" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9552" PostTypeId="2" ParentId="9542" CreationDate="2017-01-28T00:33:06.010" Score="5" Body="&lt;p&gt;I'd like to expand on jamesqf's answer. But first,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;lit side of the moon and the dark&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There are no &quot;lit&quot; and &quot;dark&quot; sides of the moon. It rotates, and whatever is dark now will be lit in two weeks time. There are definitely &lt;em&gt;near&lt;/em&gt; and &lt;em&gt;far&lt;/em&gt; sides of the moon though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem with the Earth is that it's a dynamic planet with plate tectonics, continental collision, oceanic plate subduction, rivers, rain, wind, vegetation, sedimentation and many more processes that work to obscure any impact craters on Earth. The famous &lt;a href=&quot;https://en.wikipedia.org/wiki/Chicxulub_crater&quot;&gt;Chicxulub crater&lt;/a&gt; was discovered only in the 70s. Even when we know the geological feature, it may not be recognised as an impact crater. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Sudbury_Basin#Disputes_over_origin&quot;&gt;Sudbury impact crater&lt;/a&gt; has long been known, but again only in the 70s was accepted as an impact crater.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Z6zaE.jpg&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Z6zaE.jpg&quot; alt=&quot;Sudbury&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another reason that we see many impacts on the moon and not on the Earth is their age. A very large portion of the craters on the moon formed during the &lt;a href=&quot;https://en.wikipedia.org/wiki/Late_Heavy_Bombardment&quot;&gt;Late Heavy Bombardment&lt;/a&gt;, and event that happened around 3.9 billion years ago in which many inner solar system bodies were struck by a large number of impacts. Once an impact hits the moon, the crater is there. But there are hardly any rocks on Earth that remain from that period, giving the impression that Earth was spared from it. It didn't - we just don't have any remaining (geomorphological) evidence that it happened.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-01-28T00:33:06.010" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9553" PostTypeId="2" ParentId="9549" CreationDate="2017-01-28T00:48:59.327" Score="1" Body="&lt;p&gt;When humid air rises, it reaches higher altitudes where it meets colder air. Because air is a fluid, it readily mixes with the colder air around it, lowering the vapour pressure of H&lt;sub&gt;2&lt;/sub&gt;O and condensing as liquid or solid (i.e. water or ice, respectively). This is very similar to heat transfer by &lt;a href=&quot;https://en.wikipedia.org/wiki/Advection&quot; rel=&quot;nofollow noreferrer&quot;&gt;advection&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Convection&quot; rel=&quot;nofollow noreferrer&quot;&gt;convection&lt;/a&gt;. &lt;em&gt;(also note comment by casey below)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mantle, on the other hand, is a solid. Mixing of the hot plume with the colder surroundings is extremely slow and happens only by &lt;a href=&quot;https://en.wikipedia.org/wiki/Thermal_conduction&quot; rel=&quot;nofollow noreferrer&quot;&gt;conduction&lt;/a&gt;. Rocks are terrible conductors of heat, so they only cool down &lt;a href=&quot;https://en.wikipedia.org/wiki/Adiabatic_process&quot; rel=&quot;nofollow noreferrer&quot;&gt;adiabatically&lt;/a&gt;, which is not much at all. If we look at my badly drawn phase diagram:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/s2Ckx.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/s2Ckx.png&quot; alt=&quot;decompression melting in the mantle&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see that a rising rock (the red and blue lines) does not cool rapidly enough to miss the solidus (the curve denoting the &lt;em&gt;P-T&lt;/em&gt; conditions where rock melts). Therefore, it melts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would also like to add that most rocks in mantle plumes don't actually melt, or they do so to a limited degree. Mantle plumes cause widespread melting because they rise and pool below other rocks that are less refractory (easier to melt). This can be because of their composition which is less mafic, or because they have fluxes such as water in them. The heating of these crustal rocks by the mantle plume is what usually causes widespread melting.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2017-01-28T02:44:05.383" LastActivityDate="2017-01-28T02:44:05.383" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9554" PostTypeId="2" ParentId="9544" CreationDate="2017-01-28T16:07:24.037" Score="1" Body="&lt;p&gt;Scenario #1 is relatively, somewhat, kinda, but-not-really accurate for summer, scenario #2 more so for winter. If you live in or near mountains, you are familiar with cold evening winds that come ripping through canyons and valleys to settle in basins. In mountainous vineyards of Europe, vine layout is routinely adjusted to dissipate these winds. Even if there is NO (weather-induced) wind, thermal gradients can create winds of their own. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Winters see less of these thermal gradients and in general winds will be limited to higher altitudes where they blow pretty consistently. In both of your scenarios, however, winds blow pretty consistently at higher elevations....which is why wind farms are typically found there.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-01-28T16:07:24.037" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9555" PostTypeId="1" CreationDate="2017-01-29T03:39:35.627" Score="3" ViewCount="66" Body="&lt;p&gt;I have run across many pictures of rocks that look like almost perfectly carved columns. For example: the Twyfelfontein Organ Pipes, the Basaltic Prisms of Santa Maria Regla, and the waterfall Svartifoss (pictures included on this link: &lt;a href=&quot;http://www.touropia.com/natural-rock-formations/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.touropia.com/natural-rock-formations/&lt;/a&gt;). All of the rocks I have seen that look like this have been basaltic. Is this shape caused more by how the rock originally formed, its mineralogy, or how the rock was eroded?&lt;/p&gt;&#xA;" OwnerUserId="7307" LastEditorUserId="94" LastEditDate="2017-01-29T09:27:38.650" LastActivityDate="2017-01-29T09:27:38.650" Title="What processes cause basalt to form a columnar structure?" Tags="|geology|mineralogy|erosion|igneous|" AnswerCount="0" CommentCount="4" ClosedDate="2017-01-30T08:29:39.990" ContentLicense="CC BY-SA 3.0" />
  <row Id="9556" PostTypeId="1" CreationDate="2017-01-29T09:16:22.643" Score="5" ViewCount="402" Body="&lt;p&gt;Is there any website for videos/articles that explains how to read maps or other graphics use to make forecast prediction (more advanced than the weather channel please) ?&#xA;It could be about any country/region. &lt;/p&gt;&#xA;" OwnerUserId="7396" LastActivityDate="2017-01-29T09:16:22.643" Title="Learn weather forecast" Tags="|meteorology|weather-forecasting|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9558" PostTypeId="2" ParentId="9550" CreationDate="2017-01-30T01:04:41.893" Score="2" Body="&lt;p&gt;It's a can of worms with no definitive answers, not least because, apart from a few ancient zircons, almost all the evidence has been obliterated by later processes. &#xA;Critical factors would have been the rate of crustal recycling, the rate and distribution of heat from radioactive decay, the extent and intensity of the greenhouse effect, the onset of plate tectonics, ratyes of magmatic differentiation, and the role of water in the early crust. Develop a model with your own set of assumptions - it's as likely to be as accurate as any of the multitude of models already existing. &#xA;The Hadean in total lasted about as long as the Phanerozoic, and even the early Hadean would have been not less than 100 M.a. in duration, over which time conditions changed massively. &#xA;Some temperature estimates for the Hadean include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Early Primitive mantle, about 1650 to 1850 deg C &lt;/li&gt;&#xA;&lt;li&gt;Mafic zircons 750 to    850 deg C  &lt;/li&gt;&#xA;&lt;li&gt;Late Hadean zircons from Jack Hills, West Australia, 700 deg C  &lt;/li&gt;&#xA;&lt;li&gt;Crustal rocks with plate tectonic under-thrusting, 600 deg C.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So my best guess for the early Hadean surface: Not far short of 2000 deg C. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="4507" LastEditDate="2017-01-30T03:39:30.123" LastActivityDate="2017-01-30T03:39:30.123" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9559" PostTypeId="1" AcceptedAnswerId="9563" CreationDate="2017-01-30T01:20:51.947" Score="8" ViewCount="361" Body="&lt;p&gt;This is a GOES visible channel image from 2017-01-27, about 9 a.m. local time. It's the Atlantic coast of the US. The coast is visible towards the bottom of the image. The scale is large.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This question is referring to the wavy structures that appear in the clouds. Are these 'gravity waves'?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CVXBF.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CVXBF.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="669" LastEditorUserId="192" LastEditDate="2017-01-30T15:32:27.903" LastActivityDate="2017-01-31T15:26:55.920" Title="Are these clouds exhibiting gravity waves?" Tags="|meteorology|clouds|waves|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9560" PostTypeId="1" CreationDate="2017-01-30T12:02:44.910" Score="4" ViewCount="64" Body="&lt;p&gt;I would like to obtain the angle of rotation (θ) of a detachment fault (or oceanic core complex) after X meters of rock displaced during spreading at a mid-ocean ridge.&#xA;I have a differential equation that can describe the elastic behavior of this fault: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\nabla^2(D\nabla^2w) + \rho g w = p$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;with &lt;em&gt;D&lt;/em&gt; the flexural rigidity, &lt;em&gt;w&lt;/em&gt; the deflection, &lt;em&gt;ρ&lt;/em&gt; the material density, &lt;em&gt;g&lt;/em&gt; the gravitational constant, and &lt;em&gt;p&lt;/em&gt; the load. Source and details:&#xA;&lt;a href=&quot;https://ic.ucsc.edu/~casey/eart150/Death%20Valley%20Reading/Buck,1988_Rolling%20Hinge.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://ic.ucsc.edu/~casey/eart150/Death%20Valley%20Reading/Buck,1988_Rolling%20Hinge.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not quite sure how to handle this. My aim is to plot θ against X so that I get curve models showing an fast increased of fault rotation for a certain distance of spreading, and a steady-flat evolution afterwards (showing nearly no rotation happening anymore).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I never did any geodynamic modelling before but I'm able to work days/nights to get those curves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If someone could give me a hint about the process (how to approach the problem mathematically or how to start), I would appreciate greatly.&lt;/p&gt;&#xA;" OwnerUserId="7404" LastEditorUserId="725" LastEditDate="2017-02-01T00:16:15.537" LastActivityDate="2017-02-01T00:16:15.537" Title="Determining rotation of a bending detachment fault system" Tags="|geodynamics|numerical-modelling|tectonics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9561" PostTypeId="2" ParentId="9559" CreationDate="2017-01-30T12:58:35.957" Score="2" Body="&lt;p&gt;No, these are cirrocumulus clouds displaying an undulating pattern like fish scales, giving way to the name mackerel clouds or mackerel sky.  The clouds can form  ahead of a warm front and are generally a reliable indicator that weather is going to change within a day or so.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-01-30T12:58:35.957" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="9562" PostTypeId="1" AcceptedAnswerId="9564" CreationDate="2017-01-30T17:08:51.940" Score="5" ViewCount="1098" Body="&lt;p&gt;When modelling ocean waves, a directional distribution $D_f(\theta)$ is used together with a frequency spectrum $S(f)$ to describe the energy of waves at a particular frequency $f$ and angle $\theta$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand that the directional distribution can be written as a Fourier series i.e.&#xA;$$D_f(\theta) = \frac{1}{2\pi}\left[ 1 + 2\sum_{n=1}^{\infty}\{a_n\cos(n\theta) + b_n\sin(n\theta) \} \right] $$&#xA;where $a_n = \int_0^{2\pi} D_f(\theta)\cos(\theta)\,d\theta$ and $b_n = \int_0^{2\pi} D_f(\theta)\sin(\theta)\,d\theta$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0485(1988)018%3C1020%3AAMFTRA%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kuik (1988)&lt;/a&gt;, the mean wave direction, $\theta_0$, is found by calculating &#xA;$$\theta_0 = \arctan\left(\frac{b_1}{a_1}\right)$$&#xA;where $b_1$ and $a_1$ are the first order Fourier coefficients. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alongside this definition, the author refers the reader to Borgman (1969) but I can't find this paper on the web. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is why is it only the first order Fourier coefficients $a_1$ and $b_1$ used in this calculation?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: &#xA;After giving this more thought, I think that the fact they are Fourier coefficients is somewhat of a coincidence. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the directional distribution is seen as the PDF (as the integral of it is equal to 1) then $a_1$ and $b_1$ are more like the expected values that the cosine and sine of the angle $\theta$ take. The average values can then be used in the $atan2$ function to determine the mean angle.&lt;/p&gt;&#xA;" OwnerUserId="7367" LastEditorUserId="192" LastEditDate="2017-01-30T20:26:22.437" LastActivityDate="2017-01-30T21:06:04.393" Title="The mean direction of waves in a directional distribution" Tags="|ocean|waves|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9563" PostTypeId="2" ParentId="9559" CreationDate="2017-01-30T18:31:27.873" Score="10" Body="&lt;p&gt;These are rotor clouds, and are manifestations of &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Lee_wave&quot; rel=&quot;noreferrer&quot;&gt;Lee Waves&lt;/a&gt;&quot;, a particular kind of internal &quot;gravity wave&quot; (better defined as &quot;buoyancy effect&quot;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://glossary.ametsoc.org/wiki/Forced_convection&quot; rel=&quot;noreferrer&quot;&gt;Forced convection&lt;/a&gt; helps form these clouds as warm, moist air is forced upward by both wind from behind and the mountain barrier in front. The upward movement forces cooling and condensation of vapor into clouds. Once past the mountain barrier, this instability dissipates it's momentum through a series of less intense waves as a function of distance away from the mountain range. The clouds themselves are &quot;standing&quot;: they do not move, but are constantly regenerated by the windward moist air mass; nor do they build increasingly larger as they are dissipated on their lee side.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastEditorUserId="7333" LastEditDate="2017-01-31T15:26:55.920" LastActivityDate="2017-01-31T15:26:55.920" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9564" PostTypeId="2" ParentId="9562" CreationDate="2017-01-30T20:25:11.230" Score="4" Body="&lt;p&gt;It is helpful to understand the meaning of Fourier coefficients in the directional wave spectrum analysis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A pitch-and-roll buoy measures time series of water elevation $\eta$, and slopes in both Cartesian directions, $\eta_x$ and $\eta_y$. The Fourier components $a_0$, $a_1$, $b_1$, $a_2$, $b_2$, are related to cross-spectra of elevation and slope time series (introduced by Longuet-Higgins 1963):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;a_0 = \dfrac{C_{11}}{\pi}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;a_1 = \dfrac{Q_{12}}{\pi}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;b_1 = \dfrac{Q_{13}}{\pi}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;a_2 = \dfrac{C_{22}-C_{33}}{k^2\pi}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;b_2 = \dfrac{2C_{23}}{k^2\pi}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where the cross-spectra are:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;C_{11}(f) = C[\eta(f)\eta(f)] = \int_0^{2\pi} E(f,\theta)d\theta&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;Q_{12}(f) = -Q[\eta(f)\eta_x(f)]k^{-1} = -\int_0^{2\pi} E(f,\theta)\cos{\theta}d\theta&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;Q_{13}(f) = -Q[\eta(f)\eta_y(f)]k^{-1} = -\int_0^{2\pi} E(f,\theta)\sin{\theta}d\theta&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;C_{22}(f) = C[\eta_x(f)\eta_x(f)]k^{-2} = \int_0^{2\pi} E(f,\theta)\cos^2{\theta} d\theta&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;C_{23}(f) = C[\eta_x(f)\eta_y(f)]k^{-2} = \int_0^{2\pi} E(f,\theta)\sin{\theta}\cos{\theta} d\theta&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;C_{33}(f) = C[\eta_y(f)\eta_y(f)]k^{-2} = \int_0^{2\pi} E(f,\theta)\sin^2{\theta} d\theta&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From here you can see that the mean direction, as defined in the paper that you cite, is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\theta_0 = \arctan\left({\dfrac{b_1}{a_1}}\right) = \arctan\left({\dfrac{Q_{13}}{Q_{12}}}\right) = \arctan\left({\dfrac{\int_0^{2\pi}E(f,\theta)\sin{\theta}d\theta}{\int_0^{2\pi}E(f,\theta)\cos{\theta}d\theta}}\right)&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because $Q_{12}$ and $Q_{13}$ are proportional to the integrated energy in the zonal and meridional directions, respectively, the arctangent of their ratio yields mean wave direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The authors could use higher moments to calculate direction, but this would have different physical meaning. In this specific case, using $\theta = \arctan\left({b_2/a_2}\right)$ would yield peak (dominant) wave direction in the context of pitch-and-roll buoys. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You see that the above analysis is inherently limited by the quantities that are measured, specifically $\eta$, $\eta_x$, and $\eta_y$. If higher order quantities, say $\eta_{xx}$, $\eta_{xy}$, $\eta_{yy}$ were available, the directional spectrum could be described at a higher accuracy even using just Fourier decomposition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further reading:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0485%281984%29014%3C1800%3AADAOWD%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oltman-Shay and Guza (1984)&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://www.ndbc.noaa.gov/wavemeas.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nondirectional and directional wave data analysis procedures at NDBC&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2017-01-30T21:06:04.393" LastActivityDate="2017-01-30T21:06:04.393" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9565" PostTypeId="1" CreationDate="2017-01-31T16:56:12.693" Score="4" ViewCount="140" Body="&lt;p&gt;I understand the process of volcanism and the reason for magma deposition on the surface of the earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is not clear to me, or what seems to be less well explained is why eruptions occur and then stop. What is the operative cause or causes of a flow to start or stop?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as my understanding goes there would seem to be two possible obvious explanations:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1) The magma rises in bubbles, like a lava lamp, through the earth, so the flow begins when the bubble reaches the surface and stops when the bubble is exhausted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) The magma rises as a constant stream, but causes earth to build up around the stream, eventually snuffing it out by mass accumulation. In this explanation, the lava constantly searches for thin spots where it erupts until it blocks itself off, then the pressure forces its way through some new location.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are either or both of these explanations correct or incorrect? Is there a mechanism I have not considered?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6MCuS.png&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6MCuS.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lava eruption in Iceland the size of Manhatten that began in 2014.&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2017-01-31T20:07:47.640" Title="What causes lava eruptions (and shutoffs)?" Tags="|volcanology|volcanic-eruption|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9567" PostTypeId="1" CreationDate="2017-01-31T18:42:31.183" Score="3" ViewCount="172" Body="&lt;p&gt;Everything on earth evolved around changing seasons and the different versions of resources they bring with them, so I'm curious, how did natural processes take advantage of winter qualities to shape earth as we know it? It seems like the advantages captured from other seasons are more obvious, specifically to plant life (spring- showers, summer- direct sunlight) so what's the unique aspect of winter that helps continue the process?&lt;/p&gt;&#xA;" OwnerUserId="7414" LastEditorUserId="7414" LastEditDate="2017-02-01T03:01:11.573" LastActivityDate="2017-02-01T03:01:11.573" Title="How did natural processes as we know them develop around effects of winter?" Tags="|seasons|" AnswerCount="3" CommentCount="2" ClosedDate="2017-02-01T07:29:01.463" ContentLicense="CC BY-SA 3.0" />
  <row Id="9568" PostTypeId="1" CreationDate="2017-01-31T18:42:32.240" Score="2" ViewCount="804" Body="&lt;p&gt;Do we really need to worry about the effects of burning fossil fuels when in all likelihood we won’t be burning fossil fuels in about a 100 years or maybe a little more? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We will have technologies in about 100 years where burning fossil fuels will seem like using a steam engine today. I think it will be laughable / primitive to burn fossil fuels. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It will be rare to burn fossil fuels for power and not of consequence to the environment any longer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are we really worried about when we are just going to be burning them for a little bit longer? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can we really do that much damage over the next hundred years if we are somewhat reasonable?&lt;/p&gt;&#xA;" OwnerUserId="7415" LastEditorUserId="7415" LastEditDate="2017-01-31T19:43:32.747" LastActivityDate="2017-02-01T16:17:55.337" Title="Will we even be burning fossil fuels in approx. 100 years? Worry about climate effects?" Tags="|climate-change|fossil-fuel|" AnswerCount="1" CommentCount="9" FavoriteCount="0" ClosedDate="2017-02-01T18:31:52.267" ContentLicense="CC BY-SA 3.0" />
  <row Id="9569" PostTypeId="2" ParentId="9565" CreationDate="2017-01-31T20:07:47.640" Score="2" Body="&lt;p&gt;Basaltic magma (pictured above) rises for several basic reasons: 1) High temperature, low density liquid mass that is buoyant relative to surrounding rock and 2) Low crustal overburden stresses that allow upward movement of the underlying buoyant magma.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many magmas fail to break the surface if overburden keeps them &quot;capped&quot;, but they can flow horizontally (ie between sedimentary bedding planes) if that's where the zone of weakness lies. Many may also simply lose their heat to surrounding rock and solidify on their upward migration. In many cases, buoyancy of rising magma may meet a layer of similarly dense material, effectively stopping it in its upward track.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Heat loss is important as magmas can stop flowing once relieved reservoir pressures slow upward flow to the point that rising magma cools faster than it can be replenished from below; as the flow trickles down, what's left just cools down, solidifies in place and flow stops.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, a large reservoir contains both enormous buoyancy and, importantly, heat. That heat, constantly replenished by a large supply below, will prevent excessive conductive heat loss to surrounding rock and solidification of magma pathways, ensuring the path to the surface stays open. It's also worth noting that the local stress field changes as a magma body is emptied and can also work, along with heat loss, to cap flow.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-01-31T20:07:47.640" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9570" PostTypeId="2" ParentId="9567" CreationDate="2017-01-31T20:35:08.200" Score="1" Body="&lt;p&gt;I don't know if one answer can list all the positives, but one I can think of is this: In many (not all) places of the world winter produces the most violent storms. Because deciduous trees lose their leaves during winter, they thus have less wind resistance, which in turn lessens--but does not eliminate--their vulnerability to being toppled over by severe winds.&lt;br&gt;&lt;br&gt;And of course, hibernating species take advantage of winter by sleeping through it and pretty much staying awake for the rest of the year. (I sometimes wish we humans could do the same.) &lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2017-01-31T20:35:08.200" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9572" PostTypeId="2" ParentId="9567" CreationDate="2017-02-01T00:11:48.410" Score="1" Body="&lt;p&gt;There is nothing &quot;necessary&quot; in winter, as much as nothing is &quot;necessary&quot; in any other seasons or natural phenomena. It's not like there's an all powerful being (God) that decided we needed a winter. Winter is a fact of life that occurs because of Earth's rotation tilt. It's there whether we want it or not and whether we're even here to contemplate it's &quot;necessity&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, things have evolved around the existence of winter, and the occurrence of winter has become necessary for their life. For example, some cherry cultivars taste better when exposed to cold. Winter causes fish, mammals, insects, birds, etc to migrate and subsequently breed. Ski resorts are open in winter and without it people who work there will be unemployed.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-02-01T00:11:48.410" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9573" PostTypeId="2" ParentId="9567" CreationDate="2017-02-01T00:33:54.127" Score="1" Body="&lt;p&gt;Seems to me the creation of soil may be largely due to the effects of winter.  If not for the seasonal death and decay of part of plants exposed to winter conditions, soils would be less rich.  Look at the soils in the tropical rain forest areas, which area relatively poor in nutrients, in comparisons to the rich dark soils of the great plains, where winter temperatures kill the surface plants, but reintroduce that vegetation into the soil to aid the growth of the soil for the next seasons growth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another important aspect for winter is the snow, which, besides providing skiers with entertainment, provides moisture which, being retained in the snowpack late into the spring and summer, and allows life to flourish into regions which would otherwise receive little or no precipitation in the summer months.&lt;/p&gt;&#xA;" OwnerUserId="6057" LastActivityDate="2017-02-01T00:33:54.127" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9574" PostTypeId="1" AcceptedAnswerId="9579" CreationDate="2017-02-01T03:04:05.433" Score="7" ViewCount="970" Body="&lt;p&gt;The legendary Kola superdeep borehole is about 12 km deep. To achieve such depth, a major difficulty is to make sure the borehole is vertical straight. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Intuitively, when the borehole is deep enough, it is very hard to make sure that the drilling bit is still moving downwards.  Suppose it hits some hard rock, it can be easily deflected. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, how straight is the Kola borehole? What technique is invoked in drilling straight downwards? &lt;/p&gt;&#xA;" OwnerUserId="7416" LastEditorUserId="1149" LastEditDate="2017-04-04T01:09:29.623" LastActivityDate="2017-04-04T01:09:29.623" Title="How straight is the Kola superdeep borehole?" Tags="|geology|mantle|drilling|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9576" PostTypeId="1" CreationDate="2017-02-01T14:50:55.070" Score="6" ViewCount="972" Body="&lt;p&gt;A couple of months ago I traveled into the Moroccan Atlas Mountains. Many times I have seen pictures of landmarks like this one of Aït Benhaddou which show apparently unnaturally flat mountain formations stretching across the horizon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nt4Oo.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nt4Oo.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My guess is that this is a vestige of the ice age or a huge water reservoir. Unfortunately, I could not find any good source on how they were formed. Thus my question is: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How can these formations be explained&lt;/strong&gt;?&lt;/p&gt;&#xA;" OwnerUserId="7418" LastEditorUserId="6298" LastEditDate="2017-02-01T19:30:04.407" LastActivityDate="2017-03-09T13:25:52.147" Title="Why are parts of the Atlas Mountains in Morocco flat?" Tags="|mountains|mountain-building|" AnswerCount="1" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9577" PostTypeId="1" AcceptedAnswerId="9585" CreationDate="2017-02-01T14:52:44.023" Score="5" ViewCount="275" Body="&lt;p&gt;I have come across different formulas by which the rain rate [mm/s] or [mm/h] can be computed from the drop size distribution.&#xA;I'm somehow unable to convert the different formulas into each other. It is maybe a stupid question with some unit error, but I cannot find it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A well-known formula seems:&#xA;\begin{equation}R_1 = \frac{\pi}{6} \int_0^{\infty} v(D) D^3 N(D) dD&#xA;\end{equation}&#xA;This should be the instantaneous rain rate in [mm/s]?? Unfortunately most publications just quote the formula without units...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm supposing that $D$ is in [mm], $N(D)$ in [mm$^{-1}$ m$^{-3}$], and $v(D)$ in [m s$^{-1}$].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$v(D)$ is usually approximated as $3.778\cdot D^{0.67}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another formula I have come across is &#xA;\begin{equation}&#xA;R_2 = 6\pi \cdot 10^{-4} \int_0^{\infty} v(D) D^3 N(D) dD,&#xA;\end{equation}&#xA;which is said to be [mm/h], then.&#xA;Also for $D$ in [mm], $N(D)$ in [mm$^{-1}$ m$^{-3}$], and $v(D)$ in [m s$^{-1}$].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now apparently $R_1 \cdot 0.0036 = R_2$. But why?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If $R_1$ is in [mm/s], then we should multiply by 3600 to get to [mm/h].&#xA;Can someone spot where I am wrong?&#xA;Is it right that $R_1$ is in [mm/s]? (given the units of D, N(D) as above)&lt;/p&gt;&#xA;" OwnerUserId="7419" LastEditorUserId="192" LastEditDate="2017-02-02T16:22:47.197" LastActivityDate="2017-02-02T16:53:40.063" Title="Need help understanding rain rate formulas from drop sizes" Tags="|meteorology|precipitation|rainfall|radar|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9578" PostTypeId="2" ParentId="9568" CreationDate="2017-02-01T16:13:18.587" Score="1" Body="&lt;p&gt;Based on the stats for the US only, I would say we have the capacity for using fossil fuels over the next 100 years.  Whether or not we worry about it is another discussion entirely.  The US has coal resources for the next 250 years and I suspect may be producing and using natural gas for the next 100 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the US (from the &lt;a href=&quot;http://www.eia.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;US Energy Information Administration&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;256 years of coal resources available (based on 2014 numbers) &lt;a href=&quot;http://www.eia.gov/energyexplained/index.cfm?page=coal_reserves&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;~12 years of natural gas resources available &#xA;Based on resources and current usage rate &lt;a href=&quot;http://www.eia.gov/energyexplained/index.cfm?page=natural_gas_reserves&quot; rel=&quot;nofollow noreferrer&quot;&gt;Link&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a rough estimate does not take into account importing or exporting natural gas.Also assumes usage based on 2015 numbers.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;0 years of oil resources (no surprises here)&#xA;US uses 19.4 millions of barrels per day &lt;a href=&quot;https://www.eia.gov/tools/faqs/faq.cfm?id=33&amp;amp;t=6&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt;&#xA;US produces &amp;lt;9 millions of barrels per day &lt;a href=&quot;http://www.cnbc.com/2016/04/13/us-crude-production-falls-below-9-million-barrels-per-day.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt;    &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Here is fun stat laden site for global oil and gas resource and consumption. &lt;a href=&quot;http://www.eia.gov/beta/international/&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: I take these stats at face value but oil resource production and reserve numbers are not always accurate.  A number of oil producers are reluctant to provide accurate stats as these numbers are considered sensitive to their economies.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="1149" LastEditDate="2017-02-01T16:17:55.337" LastActivityDate="2017-02-01T16:17:55.337" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9579" PostTypeId="2" ParentId="9574" CreationDate="2017-02-01T17:02:38.760" Score="6" Body="&lt;p&gt;Borehole drifted from straight vertical by ~840 meters over 12,000 meters.  All drill-bore wander side to side some and Kola borehole did not drift much until depth exceeded 5000 meters. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;See page 102 in the linked document.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Typical rotatory drill heads designed for vertical drilling can be steer to a small degree by using a simple concept: point the bit in the direction that one wants to drill. A common way to achieve this is by the use of a bend near the bit in a down hole steerable mud motor. the bend points the bit in a direction different from the axis of the well bore.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By spinning the drill head at a different rate vs the drill stem, allows the bit to drill in the direction it points.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reference: &lt;a href=&quot;http://www.muststayawake.com/SDAG/library/Kozlovsky(DeepestWell).pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;PDF&lt;/a&gt; document gives an excellent technical summary of the project. &lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="1149" LastEditDate="2017-02-04T14:48:23.470" LastActivityDate="2017-02-04T14:48:23.470" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9580" PostTypeId="1" CreationDate="2017-02-01T17:49:46.190" Score="3" ViewCount="49" Body="&lt;p&gt;I am interested in assessing a thermal spring in the Ecuadorian Andes. However I have no experience in these type of geological features and I am not sure how to proceed. The spring is located over volcanic deposits: breccias, ashes and piroclastic deposits from mid - late Pleistocene (according to the geological map). The aim is to verify if this spring (water and gas) can be used in some practical application.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The spring emits also a gas (unknown at this point) aside from water. The gas seems to be toxic since some people died last year, but only during certain hours during the night (during the day, people use this spring with no problems).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can you recommend some bibliography to start with? in reference to thermal emissions characterization, water characterization and if possible modeling of these kind of systems. If some similar case is known I will highly appreciate this information. &lt;/p&gt;&#xA;" OwnerUserId="5820" LastActivityDate="2017-02-01T17:49:46.190" Title="Thermal spring. Gas and water characterization" Tags="|geology|water|geothermal-heat|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9581" PostTypeId="1" CreationDate="2017-02-02T06:33:42.383" Score="1" ViewCount="806" Body="&lt;p&gt;Does grade of metamorphism apply to igneous and sedimentary rocks?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that grade of metamorphism applies to the scale in which a rock becomes crystallized. Or is it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please also define grade of metamorphism as a clarification.&lt;/p&gt;&#xA;" OwnerUserId="7425" LastEditorUserId="725" LastEditDate="2017-02-03T10:58:18.213" LastActivityDate="2017-02-06T16:09:16.113" Title="Does grade of metamorphism apply to igneous and sedimentary rocks?" Tags="|geology|rocks|metamorphism|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9583" PostTypeId="2" ParentId="7553" CreationDate="2017-02-02T14:23:05.100" Score="2" Body="&lt;p&gt;One addition to the excellent answers already listed is the health of the new lake would steadily deteriorate with time.  Generallly speaking,  a healthy body of water requires inflow and outflow to avoid stagnation.  In this instance,  your goal seems to be creating an evaporative pond.  That evaporation would leave behind a huge salt pit (e. g.  &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Salton_Sea&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.m.wikipedia.org/wiki/Salton_Sea&lt;/a&gt;), with very little benefits. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also,  please send me the link for a solar powered water pump! &lt;/p&gt;&#xA;" OwnerDisplayName="user7341" LastEditorDisplayName="user7341" LastEditDate="2017-02-02T14:43:48.773" LastActivityDate="2017-02-02T14:43:48.773" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9585" PostTypeId="2" ParentId="9577" CreationDate="2017-02-02T16:53:40.063" Score="3" Body="&lt;p&gt;The first equation does not match up with the units. But first things first... What you're calculating when you calculate rain rate is an accumulation rate, which is volume flux through a plane (mass flux divided by density) divided by the area of that plane. For this reason, it doesn't matter whether it is computed over a square meter or a square kilometer -- since volume flux is proportional to the area, it cancels out&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also it doesn't really matter whether $N(D)$ has units of $mm^{-1} m^{-3}$ or $cm^{-1} m^{-3}$, since that first unit cancels out in integration. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the units are as you say they are in the first example, then the expression should read&#xA;$$R_1 = 10^{-6}\frac{\pi}{6} \int_0^\infty v(D)D^3N(D)dD$$&#xA;to get a result in $mm/s$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Multiplying this by 3600 to get a result in $mm/hr$ yields the the second expression. &lt;/p&gt;&#xA;" OwnerUserId="7429" LastActivityDate="2017-02-02T16:53:40.063" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9587" PostTypeId="2" ParentId="9581" CreationDate="2017-02-03T11:06:34.073" Score="1" Body="&lt;p&gt;I'm not sure I entirely understand your questions but I'll have a go.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Does grade of metamorphism apply to igneous and sedimentary rocks?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes. Both igneous and sedimentary rocks can be metamorphosed. For example, a high grade metamorphic rock of the amphibolite facies could have been originally either a sedimentary rock or an igneous rock. It's not always straightforward to figure out if it was one or the other. Note that because igneous rocks already consist of &quot;high-grade&quot; minerals such as pyroxenes, amphiboles, feldspars, etc., and their grain size is already occasionally coarse, it may not be obvious than an igneous rock have been metamorphosed. Sometimes it takes a closer look to distinguish a metamorphic igneous rock and just an igneous rock. Sedimentary rocks, on the other hand, are originally composed of clays and other &quot;low-grade&quot; minerals so it's obvious when one is metamorphosed. A metamorphic fabric (foliation and the likes) is also much easier to develop in originally sedimentary rocks than in igneous rocks.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I know that grade of metamorphism applies to the scale in which a rock becomes crystallized. Or is it?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm not sure what the question is. Usually higher grade metamorphic rocks have larger grain size. For example, greenschist facies rocks are commonly fine grained (for example phyllites or schists) whereas eclogite facies rocks are usually composed of big beautiful crystals, sometimes in the cm scale.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Please also define grade of metamorphism as a clarification.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Start here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Metamorphism#Metamorphic_grades&quot; rel=&quot;nofollow noreferrer&quot;&gt;Metamorphic grades&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-02-03T11:06:34.073" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9588" PostTypeId="1" AcceptedAnswerId="9591" CreationDate="2017-02-03T12:24:34.120" Score="10" ViewCount="7263" Body="&lt;p&gt;My main question is how do we know that increase in global temperature does not CAUSE an increase in CO&lt;sub&gt;2&lt;/sub&gt; concentration?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am trying to develop my mental model of what's going on for the climate change issue.  There is definitely a correlation between global temperature and CO&lt;sub&gt;2&lt;/sub&gt; concentration, this is not disputed.  The general consensus is that CO&lt;sub&gt;2&lt;/sub&gt; increase causes temperature increase, why is the reverse situation not studied (if it is I could not find any studies).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This thought comes from the statement I've seen that water vapor concentration is more correlated to global temperature  than CO&lt;sub&gt;2&lt;/sub&gt;, but this is intuitive since warmer air holds more water vapor than colder air.  Does the same intuition hold for CO&lt;sub&gt;2&lt;/sub&gt;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not an expert on the subject; so I understand that I may be way off base with my reasoning.  I also openly accept  edits to my question if it is not structured or presented properly.&lt;/p&gt;&#xA;" OwnerUserId="7434" LastEditorUserId="2470" LastEditDate="2020-04-11T18:38:04.057" LastActivityDate="2021-07-28T09:27:22.407" Title="Does climate change cause increase in CO2?" Tags="|climate-change|temperature|co2|" AnswerCount="7" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="9589" PostTypeId="1" CreationDate="2017-02-03T14:30:47.297" Score="13" ViewCount="6484" Body="&lt;p&gt;Me and some of my friends were wondering what exactly is the white coating we can see on chalcedony that has been deposited by a river during quartenary (and so the original material is damaged and has a lot of cracks in it). This is an example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jz4jW.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jz4jW.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/cZyYa.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cZyYa.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Z424J.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Z424J.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Nxhl1.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Nxhl1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;What is the white coating ? Is it opal ? Cacholong ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far everything I found was this link:&#xA;&lt;a href=&quot;http://www.treasurenet.com/forums/north-american-indian-artifacts/238703-agate-arrowhead-white-patina-question.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.treasurenet.com/forums/north-american-indian-artifacts/238703-agate-arrowhead-white-patina-question.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These people describe it as &quot;patina&quot; or &quot;chalcedony weathering&quot;. I am wodering what is the process and how can we easily chemically or physically explain it ? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think it must be some kind of weathering.. similar to oxidation. I believe that it is opalization. What do you think ? I saw this forming on many agates all over the world, but only at these, that were eroded from the mother rock, transported and deposited. It is especiially common on deposited chalcedony.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="7031" LastEditorUserId="7031" LastEditDate="2017-02-06T22:41:38.540" LastActivityDate="2023-03-06T10:20:58.447" Title="What is the white coating &quot;patina&quot; we often see on deposited chalcedony/agate?" Tags="|geology|geochemistry|mineralogy|crystallography|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9590" PostTypeId="2" ParentId="9588" CreationDate="2017-02-03T16:50:57.620" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The general consensus is that co2 increase causes temperature increase, why is the reverse situation not studied (if it is I could not find any studies).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;To be brutally honest, it's not studied because what you have posited is nonsense.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, the reverse situation has been studied in a broader context. $\mathrm{CO}_2$ is soluble in water, with the solubility decreasing with increasing temperature. This is one of the key reasons the exit from a glaciation is much more rapid than is the onset of a glaciation. Atmospheric $\mathrm{CO}_2$ levels plunge during a glaciation due to absorption by the oceans. Once conditions are right for a glaciation to end, the warming makes that dissolved $\mathrm{CO}_2$ come out of solution, which causes more warming, which causes even more dissolved $\mathrm{CO}_2$ come out of solution, ... This positive feedback loop makes the exit from a glaciation quite rapid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The last time this happened was about 12000 years ago. It is not happening now. The oceans are currently absorbing most of the excess $\mathrm{CO}_2$ we humans are pumping into the atmosphere. &lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="543" LastEditDate="2017-02-04T00:47:54.743" LastActivityDate="2017-02-04T00:47:54.743" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="9591" PostTypeId="2" ParentId="9588" CreationDate="2017-02-03T18:58:03.550" Score="12" Body="&lt;p&gt;One reason is that we know exactly where the current increased CO&lt;sub&gt;2&lt;/sub&gt; comes from.  That is, we know from economic data how much petroleum, natural gas, &amp;amp; coal is extracted and burned.  From that simple chemistry lets us compute the amount of CO&lt;sub&gt;2&lt;/sub&gt; produced, and we find that (after allowing for factors such as e.g. some being absorbed by the oceans) that the amount created by burning fossil fuels matches the observed increase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(There are also more subtle measurements, such as isotope ratios, which I'm not qualified to expound in any detail...)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another reason is that for warming to have caused the observed increase in CO&lt;sub&gt;2&lt;/sub&gt;, there'd have to be some other cause for the warming.  No such cause has been found.  Suggested causes such as variation in solar output have been ruled out by measurements.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastEditorUserId="2470" LastEditDate="2020-04-12T05:43:24.303" LastActivityDate="2020-04-12T05:43:24.303" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="9592" PostTypeId="2" ParentId="9588" CreationDate="2017-02-04T03:42:06.827" Score="6" Body="&lt;p&gt;Your comparison to water vapor is a bad one.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The amount of water vapor in the atmosphere does increase with atmospheric temperature.  This is because more evaporation occurs and can be held as vapor longer, thus offsetting the equilibrium of water vapor.  Cold air will cause more water vapor to condense back to liquid.  This process of water cycling occurs on the order of hours/days.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is in stark contrast to carbon dioxide, which does not condense out of the atmosphere when it cools.  Nor does carbon dioxide evaporate from the surface of the earth.  Instead, it is a byproduct of respiration and combustion.  Carbon dioxide stays in the atmosphere for 100s of years before it gets deposited or chemically converted.  Furthermore, carbon dioxide becomes part of geological processes in the carbon cycle that takes 1000s of years, not days.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, to summarize, carbon dioxide does not directly increase in the atmosphere due to temperature rise, because it is not constantly evaporating from the Earth's surface and condensing in the atmosphere.  Carbon dioxide does not condense at normal atmospheric temperature... it won't condense until it gets as cold as -78.5 degrees C, which does not occur on the surface of the Earth [in this climate regime].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It should be noted that carbon dioxide will indirectly increase in the atmosphere with temperature rise.  This is because of feedback mechanisms.  For instance, with increasing temperature, trees will be more dry on average and will thus combust more easily.  More wildfires are expected as temperatures rise, and with them come more carbon dioxide emitted during the fire.  There is also the possibility that increases in global temperature will cause feedbacks in the geologic cycle that lead to more volcanic activity, which is another source of carbon dioxide emissions. And, as Michael points out, the methane released when permafrost melts will eventually oxidize with the hydroxyl radical into carbon dioxide and water vapor. &lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2017-02-08T03:21:08.500" LastActivityDate="2017-02-08T03:21:08.500" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="9593" PostTypeId="1" AcceptedAnswerId="9595" CreationDate="2017-02-05T02:01:27.997" Score="8" ViewCount="267" Body="&lt;p&gt;When I was very young I was always amazed that water didn't come shooting up out of the first ice-fishing hole of the season, due to the weight of all the ice. It doesn't, because the weight of the same volume of liquid water would be even heavier. Ice floats, and the thicker the ice, the lower the level of water sits down inside the hole. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is no additional hydrostatic pressure in the water beyond that due to gravity, because if there were, the ice would have been slowly pushed up to a new equilibrium position fairly quickly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I extended this thinking to volcanism, I'd wonder why volcanos can sometimes have high velocity ejecta, and also build cones from liquid that rise high above the local surface. I am guessing that the height of the cone represents effects due to hydrostatic pressure &lt;em&gt;beyond that due to the weight of material above&lt;/em&gt; (rock being less flexible than ice) but the high speed ejecta that falls far from the cone is accelerated by gas coming out of solution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the momentum of a volcano's high-velocity ejecta mostly due to expanding gas?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XjaJb.jpg&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XjaJb.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; Example of an ice-fishing hole, from &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Ministry_of_Defence_of_Russia_-_035.jpg&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2022-07-08T16:06:42.010" Title="Is the momentum of a volcano's high-velocity ejecta mostly due to expanding gas?" Tags="|volcanology|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9594" PostTypeId="2" ParentId="6680" CreationDate="2017-02-05T19:08:51.623" Score="1" Body="&lt;p&gt;Still undetermined, though a number of papers on the subject suggest global warming will increase the variance in both of the climate systems you mention. They suggest more research and more refined models are needed to narrow down the uncertainties.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some definitions:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Madden-Julian Oscillation (MJO) is the major fluctuation in&#xA;  tropical weather on weekly to monthly timescales. The MJO can be&#xA;  characterised as an eastward moving 'pulse' of cloud and rainfall near&#xA;  the equator that typically recurs every 30 to 60 days. (&lt;a href=&quot;http://www.bom.gov.au/climate/mjo/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Australian Bureau of Meteorology&lt;/a&gt;)&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The El Niño/ Southern Oscillation (ENSO) cycle refers to the coherent&#xA;  and sometimes very strong year-to-year variations in sea- surface&#xA;  temperatures, convective rainfall, surface air pressure, and&#xA;  atmospheric circulation that occur across the equatorial Pacific&#xA;  Ocean. El Niño and La Niña represent opposite extremes in the ENSO cycle. (&lt;a href=&quot;http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ensofaq.shtml#ENSO&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Weather Service Climate Prediction Center&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;El Niño is the &quot;warm phase&quot; of sea-surface temperatures in the east-central equatorial Pacific with a variety of effects on regional and global weather. La Niña is the &quot;cold phase&quot; of the oscillation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the predictive challenges is that climate change is not monotonic. It's generally held that will be a &quot;warmer-get-wetter&quot; impact -- warmer oceans produce more evaporation and therefore more precipitation. But ocean states are also affected by highly complex relationships involving currents and convection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are extracts from the abstracts of a couple of recent papers on the subject(s) (actual papers are paywalled):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In &lt;a href=&quot;http://journals.ametsoc.org/doi/10.1175/JCLI-D-16-0039.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Intermodel Uncertainty in ENSO Amplitude Change Tied to Pacific Ocean Warming Pattern&lt;/a&gt;, Zheng, et.al. compare actual sea-surface temperature measurements to the outputs of various models and write:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;To the extent that correcting model biases favors an El Niño–like mean&#xA;  warming pattern, &lt;strong&gt;this study suggests an increase in ENSO-related SST&#xA;  variance likely under global warming.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In &lt;a href=&quot;http://link.springer.com/article/10.1007%2Fs00382-013-1846-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;The MJO and global warming: a study in CCSM4&lt;/a&gt;, Subramanian, et.al, write:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The RCP8.5 run exhibits &lt;strong&gt;increased variance in intraseasonal&#xA;  precipitation, larger-amplitude MJO events, stronger MJO rainfall in&#xA;  the central and eastern tropical Pacific, and a greater frequency of&#xA;  MJO occurrence for phases corresponding to enhanced rainfall in the&#xA;  Indian Ocean sector&lt;/strong&gt;. These features are consistent with the concept of&#xA;  an increased magnitude for the hydrological cycle under greenhouse&#xA;  warming conditions.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In &lt;a href=&quot;https://www.seas.harvard.edu/climate/eli/reprints/Arnold-Branson-Kuang-Randall-Tziperman-2015.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;MJO Intensification with Warming in the Superparameterized CESM&lt;/a&gt;, Arnold, et.al. said their modeling runs showed &quot;Intraseasonal precipitation increases at a rate of roughly&#xA;10% per 1 K of warming, and MJO events become 20%–30% more frequent,&quot; but conclude:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This work adds to existing evidence that &lt;strong&gt;MJO activity may increase in&#xA;  response to global warming&lt;/strong&gt;. Evidence for an MJO dependence on SST has&#xA;  been identified in observations (Hendon et al. 1999; Slingo et al.&#xA;  1999; Jones and Carvalho 2006; Oliver and Thompson 2012), and in some&#xA;  numerical models (Lee 1999; Caballero and Huber 2010; Arnold et al.&#xA;  2013; Schubert et al. 2013). However, other models have shown negative&#xA;  or neutral trends with SST (Takahashi et al. 2011) or a strong&#xA;  dependence on the spatial pattern of warming (Maloney and Xie 2013),&#xA;  so &lt;strong&gt;any conclusions regarding future trends should be viewed as&#xA;  tentative&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2017-02-05T19:08:51.623" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9595" PostTypeId="2" ParentId="9593" CreationDate="2017-02-05T20:18:15.953" Score="10" Body="&lt;p&gt;The ejecta and their momentum appear to be entirely the product of the dissolved gasses in magma, according to this page on &lt;a href=&quot;http://www.geology.sdsu.edu/how_volcanoes_work/Controls.html&quot;&gt;Physicochemical Controls on Eruption Style&lt;/a&gt; on the How Volcanoes Work pages of the Geology Department of San Diego State University:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;The amount of dissolved gas in the magma provides the driving force&#xA;  for explosive eruptions.&lt;/strong&gt; The viscosity of the magma, however, is also&#xA;  an important factor in determining whether an eruption will be&#xA;  explosive or nonexplosive. A low-viscosity magma, like basalt, will&#xA;  allow the escaping gases to migrate rapidly through the magma and&#xA;  escape to the surface. However, if the magma is viscous, like&#xA;  rhyolite, its high polymerization will impede the upward mobility of&#xA;  the gas bubbles. As gas continues to exsolve from the viscous melt,&#xA;  the bubbles will be prevented from rapid escape, thus increasing the&#xA;  overall pressure on the magma column until the gas ejects explosively&#xA;  from the volcano. As a general rule, therefore, nonexplosive eruptions&#xA;  are typical of basaltic-to-andesitic magmas which have low viscosities&#xA;  and low gas contents, whereas explosive eruptions are typical of&#xA;  andesitic-to-rhyolitic magmas which have high viscosities and high gas&#xA;  contents.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.tulane.edu/~sanelson/Natural_Disasters/volcan&amp;amp;magma.htm&quot;&gt;A similar description is offered&lt;/a&gt; by Stephen A. Nelson, associate professor in the Department of Earth &amp;amp; Environmental Sciences at Tulane University:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;At depth in the Earth nearly all magmas contain gas dissolved in the&#xA;  liquid, but the gas forms a separate vapor phase when pressure is&#xA;  decreased as magma rises toward the surface of the Earth.   This is&#xA;  similar to carbonated beverages which are bottled at high pressure.&#xA;  The high pressure keeps the gas in solution in the liquid, but when&#xA;  pressure is decreased, like when you open the can or bottle, the gas&#xA;  comes out of solution and forms a separate gas phase that you see as&#xA;  bubbles.   Gas gives magmas their explosive character, because volume&#xA;  of gas expands as pressure is reduced.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So the gross extrusion of magma from the earth is not innately gas-dependent (though gas influences the composition of the magma), but the violent processes are caused more by gas coming out of solution and forming pressurized bubbles than gas or magma being under pressure, if that makes sense.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2017-02-05T20:18:15.953" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9596" PostTypeId="1" CreationDate="2017-02-06T10:13:27.827" Score="4" ViewCount="322" Body="&lt;p&gt;Me and some of my friends have found many rocks similar to these in central Europe - we believe that it is fossil-rich chert that originally comes from Scandinavia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/x0pYy.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/x0pYy.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/yLeR4.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yLeR4.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;There are many interesting fossils like brachiopods and sea urchins.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We find many of them in southern Moravia - there are many sandpits with quartenary sediments (mostly sands and gravel) that were deposited by river Svitava. We think that these stones must had been transported by glaciers from Scandinavia and then deposited by rivers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have searched for this material on the internet and could not find any informations about its formation or deposition. Do you have any informations please ? Could you provide me some links, pdf-thesis or an explanation  ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="7031" LastActivityDate="2017-02-06T13:00:16.883" Title="Do you have any informations about fossil-rich cherts from Scandinavia?" Tags="|geology|sedimentology|petrology|paleontology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9597" PostTypeId="2" ParentId="9596" CreationDate="2017-02-06T11:43:39.787" Score="7" Body="&lt;p&gt;What you are looking for is information about the &quot;Oslofeltet&quot; (&lt;a href=&quot;https://www.google.nl/search?q=&amp;quot;oslo-field&amp;quot;+oslofeltet&quot;&gt;Oslo-field&lt;/a&gt;) in Norway (dated to be from the Ordovicium period, 443 - 488 million years old). This is a concentrated field of of fossils. There is a &lt;a href=&quot;https://roykenbibliotek.no/cementmuseet/the-cement-museum/&quot;&gt;Sement museum&lt;/a&gt; ('cement') in a small place called &lt;a href=&quot;https://en.wikipedia.org/wiki/Slemmestad&quot;&gt;Slemmestad&lt;/a&gt; where it is possible to view fossils from what was formerly an ocean bed. Geologicaly speaking, the entire area around Slemmestad is very interesting.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="595" LastEditDate="2017-02-06T13:00:16.883" LastActivityDate="2017-02-06T13:00:16.883" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9598" PostTypeId="2" ParentId="9581" CreationDate="2017-02-06T16:09:16.113" Score="1" Body="&lt;p&gt;Metamorphic &quot;grade&quot; ONLY applies to metamorphic rocks; the &quot;grade&quot; referring to how much pressure and temperature the rock, be it sedimentary, igneous, and even metamorphic, has been subjected to. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is deduced by noting the presence of specific minerals: at key temperatures and pressures a sedimentary rock will produce specific minerals, an igneous rock, a very different array of minerals. More important than crystal size, is the degree to which the original rock has been recrystallized in noting the grade of metamorphism. &lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-02-06T16:09:16.113" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9600" PostTypeId="1" AcceptedAnswerId="9614" CreationDate="2017-02-06T17:11:04.157" Score="8" ViewCount="154" Body="&lt;p&gt;The maps shown below are from &lt;a href=&quot;https://realclimatescience.com/2017/02/nasa-noaa-climate-data-is-fake-data/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. The first shows data from two sources, while the second only shows data from one source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the difference between the two data sources used? Where does it come from, and what is the accuracy?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the reason the first map has data the second one doesn't? The most reasonable conclusion is that it comes from the ERSST data that's not in the second map, but it would be nice to know why there is a difference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gVIii.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gVIii.gif&quot; alt=&quot;ERSST + GHCNM data, Dec 2016&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qSBnv.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qSBnv.gif&quot; alt=&quot;GHCNM data, Dec 2016&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;A question was posted on the &lt;a href=&quot;https://skeptics.stackexchange.com/questions/37119/did-noaa-publish-a-fake-map-with-temperature-data-it-doesnt-have&quot;&gt;Skeptics site&lt;/a&gt; regarding the claims made in the linked blog post. However, the existing answer currently does not provide much detail and comments were posted suggesting that this site may be able to provide more information about the NOAA data and the science behind it.&lt;/p&gt;&#xA;" OwnerUserId="7447" LastEditorUserId="-1" LastEditDate="2017-04-13T12:46:45.430" LastActivityDate="2017-02-07T13:34:48.750" Title="What is the reason for differences between these GHCNM and ERSST data?" Tags="|temperature|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9603" PostTypeId="2" ParentId="9542" CreationDate="2017-02-06T19:06:52.283" Score="2" Body="&lt;p&gt;I think the question arises in part from the misconception that on the near side of the moon (the &quot;lit&quot; side as it was referred to) the Earth fills much of the sky and blocks most incoming impactors. (Do correct me if I am wrong.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is incorrect. The Earth is ~12 Mm in (polar) diameter and ~360 Mm from the moon. Using the small angle approximation ($tan \theta = \theta$ in radians) we get an angular diameter of $\theta \approx tan \theta = 12/360 = 0.0333 \approx 2^{\circ}$. In other words, the Earth fills only a small portion of the sky. (Which is still about $(2^\circ \div 0.5^\circ)^2 = 16$ times the angular area of the moon as seen from Earth). You can see this for yourself by looking at the Apollo photographs. (Note: the 360 Mm distance is at perigee. Apogee is a little further and I also didn't account for the fact that equatorial diameter is larger. The numbers hardly change. There is a &lt;a href=&quot;https://astronomy.stackexchange.com/questions/7736/what-is-the-angular-diameter-of-earth-as-seen-from-the-moon&quot;&gt;question on Astronomy Stack Exchange&lt;/a&gt; if you want a more accurate answer.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Above I was simply correcting a (perceived) geometric misunderstanding. We must also account for gravity. Remember that impactors need not strike either Earth or moon from the exact same direction that they approached the Earth-Moon system. For example, a comet which passes close to the Earth can have its trajectory bent by the Earth's gravity, so that it impacts the near side of the moon (coming from the direction of the planet) even though its path before did not go near the moon. The path of a body passing near the Earth will look approximately like a hyperbola with the planet at the focus.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Combine the above with the fact that impactors can come from any direction, and you see that on both Moon and Earth you could find craters in any location.&lt;/p&gt;&#xA;" OwnerUserId="7449" LastEditorUserId="-1" LastEditDate="2017-04-13T12:59:06.653" LastActivityDate="2017-02-06T19:18:43.440" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9607" PostTypeId="1" CreationDate="2017-02-06T20:28:30.830" Score="9" ViewCount="193" Body="&lt;p&gt;Around the time climate change became a 'public issue' (let's say shortly after &lt;a href=&quot;https://en.wikipedia.org/wiki/An_Inconvenient_Truth&quot; rel=&quot;nofollow noreferrer&quot;&gt;An inconvenient truth&lt;/a&gt; came out), figures started getting published about the expected (global) sea level rise in case of 'catastrophic' meltdowns of the large land ices masses.&lt;br /&gt;&#xA;Quoting from Table 4.1 in the &lt;a href=&quot;http://www.climatechange2013.org/images/report/WG1AR5_Chapter04_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;2013 IPCC report (Ch. 4, the Cryosphere)&lt;/a&gt; these are approximately:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;58.3 meters for the Antarctic ice sheet&lt;/li&gt;&#xA;&lt;li&gt;7.4 meters for the Greenland ice sheet&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Other reports quoted similar numbers, e.g. in &lt;a href=&quot;http://pubs.usgs.gov/fs/fs2-00/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Poore, R.Z., Williams, R.S., Jr., and Tracey, Christopher, 2000, Sea level and climate: U.S. Geological Survey Fact Sheet 002–00&lt;/a&gt; this was split into: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;East Antarctic ice sheet: 64.8&lt;/li&gt;&#xA;&lt;li&gt;West Antarctic ice sheet: 8.1&lt;/li&gt;&#xA;&lt;li&gt;Greenland: 6.6&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;These are world-wide numbers, i.e. sea level rise would be distributed equally over all oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Somewhere in 2013 (IIRC) new research came out, also considering the gravitational effects &lt;strong&gt;of the ice masses themselves&lt;/strong&gt;, which result in a non-uniform distribution of the meltwater (&lt;a href=&quot;http://news.harvard.edu/gazette/story/2015/09/ups-and-downs-of-sea-level/&quot; rel=&quot;nofollow noreferrer&quot;&gt;example&lt;/a&gt;).&lt;br /&gt;&#xA;In my country, The Netherlands, the expected sea level rise in case of a Greenland 'meltdown' would not be 6 meters, but less, in the order of 2-3 meters.&lt;br /&gt;&#xA;IIRC, sea level on the eastern US coast would actually &lt;em&gt;drop&lt;/em&gt; in this scenario.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question&lt;/strong&gt;: I'm looking for a dataset showing the expected sea level rise, at any place on earth, taking these gravitational effects into consideration, for the 3 scenarios 'melting of Greenland, Western Antactica, entire Antactica'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to use this to have people indicate where they live, and then show them what would happen at their place.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So this would have the following requirements:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;inland data available as deep inland as the land would be affected (that's coastal regions and preferably rivers as well);&lt;/li&gt;&#xA;&lt;li&gt;input could be longitude/latitude. I would have to convert city names or map coordinates to this;&lt;/li&gt;&#xA;&lt;li&gt;for practical reasons I'm looking for off-line data that I can download&lt;br /&gt;(unreliable Internet available at the place I want to use this).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I'm not sure what scale/resolution would be required, I'm letting that depend on what's available.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: I could've asked this question on &lt;a href=&quot;https://opendata.stackexchange.com/&quot;&gt;OpenData&lt;/a&gt;, but my guess is I'll have more success here.&lt;/p&gt;&#xA;" OwnerUserId="595" LastEditorUserId="2470" LastEditDate="2021-07-06T07:07:16.837" LastActivityDate="2021-07-06T07:07:16.837" Title="Dataset for expected sea level rise in case of massive meltdowns (Greenland/Antarctica)" Tags="|climate-change|sea-level|open-data|antarctica|greenland|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9608" PostTypeId="1" CreationDate="2017-02-06T20:52:52.697" Score="4" ViewCount="158" Body="&lt;p&gt;I am trying to find heating degree days forecast data &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;for a certain state&lt;/li&gt;&#xA;&lt;li&gt;for a long period ( &gt; 3 mons)&lt;/li&gt;&#xA;&lt;li&gt;published by the US government or universities.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;What I found:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Heating Degree Days W. N. Central, Monthly by EIA.com. This one has forecast to 2018, but it forecast the entire W.N. Central region.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/cdus/degree_days/hfstwpws.txt&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.cpc.ncep.noaa.gov/products/analysis_monitoring/cdus/degree_days/hfstwpws.txt&lt;/a&gt; Here is a state-wide forecast, but it only forecast 7-day.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;This 2 data don't meet all the requirements. I was wondering if anyone know data that would meet all the requirements?&lt;/p&gt;&#xA;" OwnerUserId="7453" LastActivityDate="2017-02-06T20:52:52.697" Title="Heating degree days forecast" Tags="|meteorology|open-data|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="9609" PostTypeId="2" ParentId="9607" CreationDate="2017-02-07T00:47:41.243" Score="2" Body="&lt;p&gt;You should try to use the equations and maps presented by Mitrovica et al., (2011), entitled &lt;a href=&quot;https://academic.oup.com/gji/article/187/2/729/571441/On-the-robustness-of-predictions-of-sea-level&quot; rel=&quot;nofollow noreferrer&quot;&gt;On the robustness of predictions of sea level fingerprints&lt;/a&gt;.  In this paper they present the history of sea level rise equations and then present their own robust equation with comparisons.  There are maps showing the differences as well.  Soon they will provide fortran code so that you can try it out yourself, which will be published &lt;a href=&quot;http://www.psmsl.org/train_and_info/geo_signals/fingerprints/pseudo_spectral_1D/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-02-07T00:47:41.243" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9610" PostTypeId="1" AcceptedAnswerId="9613" CreationDate="2017-02-07T12:31:56.190" Score="7" ViewCount="4820" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;Magnetic declination, sometimes called magnetic variation, is the&#xA;  angle between magnetic north and true north. Declination is positive&#xA;  east of true north and negative when west. Magnetic declination&#xA;  changes over time and with location. As the compass points with local&#xA;  magnetic fields, declination value is needed to obtain true north.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is the definition provided by &lt;a href=&quot;https://www.ngdc.noaa.gov/geomag/declination.shtml&quot;&gt;National Center For Environmental Information&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can read, magnetic declination depends on location (lat/lon) and time but I would like to know if it also depends on the altitude and why it does or does not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: possibly attach some reference to the answer.&lt;/p&gt;&#xA;" OwnerUserId="7458" LastEditorUserId="2536" LastEditDate="2017-02-07T13:38:34.557" LastActivityDate="2019-07-28T12:01:25.547" Title="Does Magnetic Deviation depend on altitude?" Tags="|geomagnetism|magmatism|magnetosphere|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9612" PostTypeId="2" ParentId="9576" CreationDate="2017-02-07T13:18:00.637" Score="3" Body="&lt;p&gt;Once the sediments (mainly silt and sand) have been deposited as layers in an ocean, when the sea level was much higher. Thus, each layer is very homogeneous in its texture, hardness and stability against weathering and erosion. Therefore vertical forces of erosion have a uniform effect on the entire surface and the ridge remains flat when there is no deformation due to tectonic strain. But lateral erosion has different effects on the different hard layers and so you see ribs on the mountains flanks. So it is mainly due to the layer homogenity and due to the absence of tectonic deformation that you see in the background.  &lt;/p&gt;&#xA;" OwnerUserId="7459" LastActivityDate="2017-02-07T13:18:00.637" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9613" PostTypeId="2" ParentId="9610" CreationDate="2017-02-07T13:30:22.473" Score="8" Body="&lt;p&gt;Technically yes, but practically, usually no. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The magnetic field varies in three dimensions and the variations are not parallel to the Earth's surface. However, horizontal distances varies usually on a larger magnitude than elevation and for everyday use, the declination is only based on horizontal position. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The common model for the Earth's magnetic field, &lt;a href=&quot;http://earth-planets-space.springeropen.com/articles/10.1186/s40623-015-0228-9&quot;&gt;IGRF-12&lt;/a&gt; (International Geomagnetic Reference Field) uses the radial distance from the center of the Earth &lt;em&gt;(r)&lt;/em&gt; in relation to the geomagnetic conventional Earth’s mean reference spherical radius &lt;em&gt;(a)&lt;/em&gt;. In other words, the elevation. &lt;em&gt;(a/r)&lt;/em&gt; will usually be almost &lt;em&gt;1&lt;/em&gt;, and the difference is less than any other uncertainties in the measurements, e.g. deviation due to &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnetic_anomaly&quot;&gt;magnetic anomalies&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The magnetic field is often calculated by using the &lt;a href=&quot;https://www.ngdc.noaa.gov/IAGA/vmod/igrf12coeffs.txt&quot;&gt;published model&lt;/a&gt; and &lt;a href=&quot;https://www.ngdc.noaa.gov/IAGA/vmod/igrf12.f&quot;&gt;this&lt;/a&gt; code. As you can see (the code is rather easy to read), the vertical component is used to estimate the magnetic field for every location. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Online calculators are often used to correct declination for navigational purposes: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.ngdc.noaa.gov/geomag-web/?model=igrf&quot;&gt;NOAA's&lt;/a&gt; calculator doesn't include elevation and is calculated at sea level. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://www.geomag.bgs.ac.uk/data_service/models_compass/igrf_form.shtml&quot;&gt;BGS's&lt;/a&gt; and &lt;a href=&quot;http://www.ga.gov.au/oracle/geomag/agrfform.jsp&quot;&gt;GA's&lt;/a&gt; calculators does, but the elevation have a small impact on the declination. Try it to see! &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Simpler models, e.g the &lt;a href=&quot;https://en.wikipedia.org/wiki/Dipole_model_of_the_Earth%27s_magnetic_field&quot;&gt;dipol model&lt;/a&gt; also suggest how the magnetic declination varies with distance from the Earth's magnetic center. The approximation work rather well at low latitudes and at the Earth's surface. It can also be used to model Earth's magnetic field in an astronomical context. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apart from declination, there is also an &lt;em&gt;inclination&lt;/em&gt; to take into account. Near the magnetic poles, the compass needle will not be horizontal, but get a dip. This can make normal field compasses almost useless near the magnetic poles (trust me, I tried..). &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-02-07T13:54:27.757" LastActivityDate="2017-02-07T13:54:27.757" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9614" PostTypeId="2" ParentId="9600" CreationDate="2017-02-07T13:34:48.750" Score="5" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;The maps shown below are from here.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Actually, except for the deplorable comments (your &amp;quot;here&amp;quot; was a self-titled deplorable blog site), the maps are from &lt;a href=&quot;https://www.ncdc.noaa.gov/temp-and-precip/global-maps/201612&quot; rel=&quot;noreferrer&quot;&gt;NOAA itself&lt;/a&gt;. The maps without deplorable annotations:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://www.ncdc.noaa.gov/sotc/service/global/map-percentile-mntp/201612.gif&quot; alt=&quot;Map showing land and ocean temperature percentiles for December 2016, from NOAA's National Centers for Environmental Information, data source: GHCN-M 3.0.0 and ERSST version 4.0.0. Coverage is nearly complete from 60° south to 66° north latitude.&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://www.ncdc.noaa.gov/sotc/service/global/map-land-sfc-mntp/201612.gif&quot; alt=&quot;Map showing land-only temperature departures for December 2016, from NOAA's National Centers for Environmental Information, data source: GHCN-M 3.0.0. Coverage is rather spotty except for the continental USA, western Europe, and eastern Asia.&quot; /&gt;&lt;/p&gt;&#xA;&lt;br&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;What is the difference between the two data sources used?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The most obvious difference is that as the name implies, the ERSST includes data from over the oceans. These data are gathered by buoys, ships, and satellites. A not so obvious difference is that NOAA's  merged land–ocean surface temperature analysis incorporates GHCN-M land-based stations that are not used in the GHCN-M land-only map. The locations and ages of the 7280 Global Historical Climatology Network (GHCN) stations are depicted below. Note that the vast majority of the stations in Africa are less than twenty years old.&#xA;&lt;img src=&quot;https://www1.ncdc.noaa.gov/pub/data/metadata/images/C00839_GHCNM-Stations.jpg&quot; alt=&quot;Map showing the location and age of the 7280 Global Historical Climatology Network (GHCN) stations. Most of the stations in Africa are less than 20 years old.&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;The land-only analysis uses GHCN-M stations only. It does not use satellite data. Because of this it excludes stations that don't have a solid history of measurements from 1981. This would include the GHCN-M station at the &lt;a href=&quot;https://www.ncdc.noaa.gov/cdo-web/datasets/GHCND/stations/GHCND:RWM00064387/detail&quot; rel=&quot;noreferrer&quot;&gt;Kigali International Airport in Rwanda&lt;/a&gt;, whose data coverage over the last 40+ years is only 48%. The GHCN-M-based land-only map only uses about 2600 of the 7280 GHCN-M stations.&lt;/p&gt;&#xA;&lt;p&gt;The NOAA Merged Land Ocean Global Surface Temperature Analysis uses satellite data as a sanity check. This enables it to use most of the ~4700 GHCN-M stations excluded from the land-only map.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-02-07T13:34:48.750" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="9615" PostTypeId="2" ParentId="8806" CreationDate="2017-02-07T13:37:08.960" Score="7" Body="&lt;p&gt;Beyond the answers above, here is a small river near Berca, Romania, where active mud volcanism and salt diapirism are widespread, explaining the high salinity of this water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BNpMX.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BNpMX.jpg&quot; alt=&quot;my own picture&quot;&gt;Salty river. Note box for scale. (My own picture, geotagged)&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1379" LastEditorUserId="1379" LastEditDate="2017-02-09T14:59:13.767" LastActivityDate="2017-02-09T14:59:13.767" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9616" PostTypeId="2" ParentId="2302" CreationDate="2017-02-07T15:03:03.947" Score="-2" Body="&lt;p&gt;The geothermal energy is produced in 3 main ways: When the Earth is formed eons ago, the kinetic energy of the mass that rammed into the surface of the earth turned into heat. Earth gravity force further compressed the materials that also generated some heat, element natural decay caused nuclear fission energy be produced. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, the Moon, the Sun’s gravity caused periodical (very slightly) distortions on Earth that also generate some heat though very little.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In these sources of heat: The Earth forming process stopped and the kinetic energy turned into heat no longer have supply. The gravity compress effect that generate heat no longer significant because matter already dense enough in Earth. Radioactive elements on Earth only can be consumed but no further supply from space; the heat they produced will be weaker and weaker when time elapse along. The tidal movement caused heat is too little on the Earth to compensate the loss of heat through natural dissipation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The heat produced from the core (20×〖10〗^12W) cannot compensate the heat that being conducted to surface and dissipated out into space (44×〖10〗^12W).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So as an observed fact, the Earth’s total mass is cooling all the time. When there is no supply (or not enough supply) while there is a constant loss (natural energy dissipation) or accelerated loss (manmade energy dissipation by tapping into geothermal energy), it is a simple mathematical logic: the Earth’s geothermal energy is not sustainable --- don’t even mention renewable. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Someone argue: the Earth is so big and we are so small, we use a little bit of geothermal energy, it doesn’t matter. OK, if this proportional difference can allow human to use the geothermal energy long enough to the time the Sun’s life span is going to end and start to swell and scorch the Earth, then it makes sense. Otherwise it is non-sense. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then how long it can last if we use geothermal energy?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is some rough calculation (because in this case we only need some qualitative analysis to decide sustainability issue on geothermal energy):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In 2006, human use 16 trillion w /s;&lt;br /&gt;&#xA;Earth total mass: 5.9763×〖10〗^24kg;&lt;br /&gt;&#xA;Mean density: 5517kg/M^3;&lt;br /&gt;&#xA;Estimated average heat capacity: 700 J/kg ℃;&lt;br /&gt;&#xA;Kilowatts/hour= 3.6×〖10〗^6Joule;&lt;br /&gt;&#xA;16 trillion w/s = 〖16×10〗^9kw×〖60〗^2s= 〖57.6×10〗^12kw/h;&lt;br /&gt;&#xA;1℃ down for Earth total mass:&lt;br /&gt;&#xA;5.9763×〖10〗^24kg×700 J/kg÷ (3.6 ×〖10〗^6Joule)&lt;br /&gt;&#xA;=1162×〖10〗^18kw/h;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How many years human use can cause 1℃ down for Earth total mass?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1162×〖10〗^18kw/h÷〖57.6×10〗^12kw/h×24h×7d×52w = 2309year&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How many years human use can cause 200℃ down for Earth total mass?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2309year×200℃ = 461,800year&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How many years we taking off our descendants by using geothermal energy for one year by this rate?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2 billion year/461,800year≈4331year&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The heat inside the Earth is the living force that keeps the Earth alive --- the heat inside the Earth resist water be sipped into the Earth, keep the molten core flowing that maintain the magnetic fields of the Earth that protect all lives on it and that also protect the atmosphere not been blown away by solar wind, keep continental plates moving that make mountains which keep the Earth uneven to maintain weather and prevent all Earth surface be submerged into 50 meters of water…&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth with weakened geothermal energy will become another Mars.&lt;/p&gt;&#xA;" OwnerUserId="7461" LastEditorUserId="595" LastEditDate="2017-02-07T16:14:11.123" LastActivityDate="2017-02-07T16:14:11.123" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9618" PostTypeId="1" AcceptedAnswerId="9624" CreationDate="2017-02-07T19:14:18.940" Score="8" ViewCount="322" Body="&lt;p&gt;I am a high school Biology teacher with a crazy passion for climate and environmental changes. I wish I had known this before I started college. I have been out of college for a year and have been teaching ever since. I would really love to learn more about climate, weather, atmosphere and maybe even go back to school for this. What would be the best approach? I have a B.A. in Biological Science. Would I go back for a B.A. in Atmospheric sciences or just jump into a Masters? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any books on the topic of climate/climatology that you would recommend?   &lt;/p&gt;&#xA;" OwnerUserId="7467" LastEditorUserId="6" LastEditDate="2017-02-07T20:32:29.757" LastActivityDate="2017-05-02T18:04:28.540" Title="Climatology Career" Tags="|climate|climatology|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9619" PostTypeId="2" ParentId="9588" CreationDate="2017-02-07T19:56:34.977" Score="3" Body="&lt;p&gt;There are processes operating on geological timescales that link CO&lt;sub&gt;2&lt;/sub&gt; (specifically CO&lt;sub&gt;2&lt;/sub&gt;, not GHGs) to changing temperature, namely chemical weathering (the chemical breakdown of in situ rock at/near the Earth surface). When aluminosilicate minerals react with carbonic acid (rainwater+CO&lt;sub&gt;2&lt;/sub&gt; formed in the atmosphere), minerals dissolve, releasing their cations (e.g. Si&lt;sub&gt;2&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;, Al&lt;sub&gt;2&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt;, Ca&lt;sub&gt;2&lt;/sub&gt;&lt;sup&gt;+&lt;/sup&gt; etc) and soluble anions (e.g. bicarbonate 2CO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;-&lt;/sup&gt;). These get washed to the ocean where calcium carbonate shelly organisms incorporate them into their shells, eventually die, and fall to the sea floor. This is a principle geological mechanism for removing CO&lt;sub&gt;2&lt;/sub&gt; from the atmosphere and an important part of the carbon cycle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The link to climate comes from its control on weathering processes. Generally, chemical weathering processes are more efficient when it is wetter and warmer. So at planetary scale, over long time periods, if it gets warmer, the amount of CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere should decrease, which in turn reduces the greenhouse effect. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So from this basic physical understanding, your premise that increasing temperature can CAUSE increased CO&lt;sub&gt;2&lt;/sub&gt; concentrations has little to no basis in relation to our understanding of the climate and carbon systems, quite the opposite in fact (temperature increases cause draw down of CO&lt;sub&gt;2&lt;/sub&gt; due to chemical weathering). Alternatively, we have a known mechanism (the greenhouse effect) supported by empirical observations that CO&lt;sub&gt;2&lt;/sub&gt; influences global temperature.&lt;/p&gt;&#xA;" OwnerUserId="401" LastEditorUserId="2470" LastEditDate="2020-04-12T05:47:05.853" LastActivityDate="2020-04-12T05:47:05.853" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="9620" PostTypeId="1" AcceptedAnswerId="9621" CreationDate="2017-02-08T01:22:14.223" Score="3" ViewCount="992" Body="&lt;p&gt;We hear about people being injured or killed, or property being damaged or destroyed, by flash floods all the time. Or by straight line winds. Or by hail. Or by tornadoes. Why not lightning?&lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2024-02-25T22:11:44.410" Title="Why don't lightning strikes cause a lot of injury or damage to property?" Tags="|lightning|thunderstorm|" AnswerCount="4" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9621" PostTypeId="2" ParentId="9620" CreationDate="2017-02-08T01:41:09.817" Score="6" Body="&lt;p&gt;About 51 people die from lightning strikes per year in the United States. Part of the reason is the low probability of being hit by lightning. Tornadoes, hail, and straight line winds sweep large areas, while one lightning bolt covers a rather small area, and may even be harmless if it doesn't make contact.&lt;/p&gt;&#xA;&lt;p&gt;Think of it this way: if you were struck by lightning, a person 500 feet away may not be harmed by it, but if straight line winds cause your house to collapse, you can say with relative certainty that your neighbor will have some damage.&lt;/p&gt;&#xA;&lt;p&gt;Another factor is the reliability of protection. Major hail can total a car. Strong straight line winds and tornadoes can collapse or remove your house. A lightning bolt will cause property damage, but you will be safe inside, provided you aren't touching metal.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="30077" LastEditDate="2024-02-25T22:11:44.410" LastActivityDate="2024-02-25T22:11:44.410" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="9622" PostTypeId="1" CreationDate="2017-02-08T02:31:25.197" Score="1" ViewCount="39" Body="&lt;p&gt;What is the typical &lt;a href=&quot;http://petrowiki.org/Production_forecasts&quot; rel=&quot;nofollow noreferrer&quot;&gt;production profile&lt;/a&gt; of oil fields with &lt;a href=&quot;http://petrowiki.org/Water_and_gas_coning&quot; rel=&quot;nofollow noreferrer&quot;&gt;water coning&lt;/a&gt;?&lt;/p&gt;&#xA;" OwnerUserId="7471" LastEditorUserId="2536" LastEditDate="2017-02-08T09:04:01.370" LastActivityDate="2017-02-08T09:04:01.370" Title="Oil production profile of oil fields with water coning" Tags="|models|petroleum|" AnswerCount="0" CommentCount="2" ClosedDate="2017-03-31T13:08:26.533" ContentLicense="CC BY-SA 3.0" />
  <row Id="9623" PostTypeId="2" ParentId="9620" CreationDate="2017-02-08T03:37:17.647" Score="3" Body="&lt;p&gt;Unlike storms and floods, lightning strikes a single point. So the area directly affected by lightning is small in comparison. Another thing to consider is that when you see lightning, that does not mean it touched down to the ground.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, keep in mind the fundamental way that lightning causes destruction, death, property damage, etc: wildfires.  Most wildfires are caused by lightning.  In the USA alone, over 10,000 lightning-caused wildfires are reported each year.  And, nearly 4 million acres are burned by those fires.  See the &lt;a href=&quot;https://www.nifc.gov/fireInfo/fireInfo_stats_lightng.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NIFC&lt;/a&gt; for more information.  So, while it is unlikely to get struck directly by lightning, the fires that are caused by lightning cause many deaths and vast amounts of property damage, which dwarfs the damage caused by floods and storms.  &lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2017-02-08T03:43:03.453" LastActivityDate="2017-02-08T03:43:03.453" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9624" PostTypeId="2" ParentId="9618" CreationDate="2017-02-08T03:58:23.007" Score="5" Body="&lt;p&gt;You do not need another Bachelor's degree.  After graduating with a bachelors degree in natural science, I taught high school for three years, and then went to graduate school to study air quality in an environmental engineering program.  Many students in my group studied air quality / climate change interactions and climate change was a significant part of our class curriculum.  If you have good computer skills and a good academic record, then you should have no problem finding a university that will fund you to do Master's work in climate-related environmental sciences.  Universities need graduate students because they perform a fundamental duty (e.g. teaching or researching) at a low cost compared to a professor or post-doc.  However, you should keep in mind that after you graduate, you may not be able to find a job doing what you want in climate-science, unless you are prepared to write funding proposals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Climate change is a vast field which is not all about the atmosphere. Biology plays a significant role.  I would suggest you try to get involved with climate-related marine biology, changes in ecosystems due to climate change, or the effects that increased carbon/temperature have on plants/animals.  Though, jumping into atmospheric science as your primary area of study will put you at a competitive disadvantage since many graduate students will have studied that in their Bachelor's program.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for a book, I suggest you read David MacKay's &lt;a href=&quot;https://www.withouthotair.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;Sustainable Energy, without the hot air&quot;&lt;/a&gt;, and I also suggest you familiarize yourself with the &lt;a href=&quot;https://www.ipcc.ch/&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC reports&lt;/a&gt; and &lt;a href=&quot;http://www.globalcarbonproject.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Carbon Project&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2017-02-09T03:11:44.203" LastActivityDate="2017-02-09T03:11:44.203" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9625" PostTypeId="2" ParentId="2956" CreationDate="2017-02-08T09:58:44.600" Score="8" Body="&lt;p&gt;I'd like to add a bit to the existing answer and maybe break it down to several simple things:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;strong&gt;Chloride likes water.&lt;/strong&gt; The chloride ion, Cl&lt;sup&gt;-&lt;/sup&gt; really likes being in water. It's one of the most incompatible elements in mantle melts, and it readily partitions into fluids exsolved from magmas. Basically, it's enriched in silicic rocks (that are forming most of the crust) and then it's just a small step to remove the chloride from the magmas to the fluids, which then end up in the ocean or in the atmosphere (and then the ocean because it rains). Once it's in the water, it's very hard to remove it from there.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Chlorides are very soluble.&lt;/strong&gt; Sodium chloride, magnesium chloride, calcium chloride, copper chloride, and a many other chlorides are very soluble in water. Therefore, if you take any acidic water with some amount of chloride in it, and react it with rocks, it's going to leach stuff away. The fluid will become rich in all of that stuff. Particularly sodium, magnesium, calcium and potassium because these are the most common chloride-soluble elements in the crust. I would add that potassium is usually held more tightly to solid phases such as micas, so it's somewhat less mobile than sodium when bound to silicates.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Sodium chloride has no major solid sink.&lt;/strong&gt; Calcium chloride is more soluble than sodium chloride. Based on this simplistic approach, you would expect to have more calcium to be more abundant in the ocean than sodium. Thing is, it forms calcium carbonate. Whether chemically precipitated or biogenic, a lot of calcium is removed as calcite and aragonite from the oceans. Magnesium goes that way too. Sodium does not precipitate. Therefore, it stays in the ocean.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-02-08T09:58:44.600" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9629" PostTypeId="1" CreationDate="2017-02-08T16:13:27.530" Score="8" ViewCount="81" Body="&lt;p&gt;It &lt;a href=&quot;https://phys.org/news/2016-10-mercury.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;appears&lt;/a&gt; that Mercury shows some cracks on its surface that were not caused by moving tectonic plates but by shrinking due to the inner metal core cooling.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth is also cooling down, but are there any signs that shows effects of this cooling of the core, or are they masked by tectonic plate movements, erosion, or other effects?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="2570" LastEditDate="2018-01-29T17:34:49.377" LastActivityDate="2018-01-29T17:34:49.377" Title="Are there any signs on the Earth's surface that indicate a shrinking iron core?" Tags="|geophysics|core|crust|iron|" AnswerCount="0" CommentCount="3" ClosedDate="2018-01-30T10:59:07.317" ContentLicense="CC BY-SA 3.0" />
  <row Id="9630" PostTypeId="1" CreationDate="2017-02-08T23:27:24.277" Score="5" ViewCount="399" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/All_models_are_wrong&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;All models are wrong but some are useful&quot;&lt;/a&gt;. I am not against the concept of anthropogenic climate change because climate models may not be strong source of information for climate change. Observation data in the last 30 years or more are enough to prove that human related emissions are affecting the radiative and thermal properties of land, ocean and atmosphere. This question is about climate models which are based on approximations in so many ways.  I am deeply concerned that most modelers tune their models for the right or wrong reasons to produce &quot;quality&quot; publications on peer-reviewed journals. They seem to say, &quot;look at my model, it perfectly reproduced what is observed&quot;. But we know that, there are so many approximations for turbulence, micro-physics, land surface fluxes, and so forth. The numerical solution approximation by itself imposes serious limit to the accuracy of climate models. Some manuscripts that I found are &quot;too accurate to be true&quot;. Then my question is how accurate can a climate model be? Are there methods to check the accuracy of those publications claiming to be true?   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: This question is broad and it requires broad answer based on  uncertainties imposed on climate models by approximations at each level of the model development and indicate the maximum  achievable accuracy level. In my mind something like the following conceptual figure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Warning:&lt;/em&gt;&lt;/strong&gt; The following figure is not based on any study or realistic data. It is just something I have produced for something the answer to my questions may look like. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/lYS3l.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lYS3l.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4877" LastEditorUserId="4877" LastEditDate="2017-02-15T02:45:21.123" LastActivityDate="2017-02-15T02:45:21.123" Title="How accurate are climate models?" Tags="|climate-change|climate-models|" AnswerCount="0" CommentCount="11" ClosedDate="2017-02-15T06:49:31.177" ContentLicense="CC BY-SA 3.0" />
  <row Id="9632" PostTypeId="1" CreationDate="2017-02-09T02:04:13.227" Score="3" ViewCount="110" Body="&lt;p&gt;I have u-wind, v-wind and w-wind at 11 pressure levels (starting from 1000 to 100). I would like to calculate column averaged kinetic energy. I have the formula to do this as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$KE=\frac 1{g(Ps-Ptop)} $$&#xA;\int_{Ptop}^{Ps}\frac 12(u^2+v^2+w^2)dp$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is how to use this formula to compute column averaged kinetic energy? Can I do it simply as follows:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$KE=\frac 1{9.8(1000-100)}\frac12[ \sum_{Ptop}^{Ps}(u^2+v^2+w^2)] $&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where the [ ] is the sum of  $u^2+v^2+w^2$ at all 11 pressure levels&lt;/p&gt;&#xA;" OwnerUserId="3194" LastActivityDate="2017-02-09T02:04:13.227" Title="How to calculate column averaged kinetic energy?" Tags="|meteorology|atmosphere|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9634" PostTypeId="1" CreationDate="2017-02-09T08:35:04.953" Score="9" ViewCount="3211" Body="&lt;p&gt;I have $u$-wind, $v$-wind and specific humidity. I would like to compute moisture flux convergence at a grid point. So I need to compute the value of $q(\frac{du}{dx} + \frac{dv}{dy})$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is how to compute $\frac{du}{dx}$ and $\frac{dv}{dy}$ from $u$-wind and $v$-wind at gird point $(x,y)$? &lt;/p&gt;&#xA;" OwnerUserId="3194" LastEditorUserId="3194" LastEditDate="2017-02-14T00:49:12.727" LastActivityDate="2017-07-02T22:42:39.697" Title="How to compute du/dx and dv/dy in moisture flux convergence?" Tags="|meteorology|atmosphere|atmosphere-modelling|moisture-flux|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="9635" PostTypeId="1" CreationDate="2017-02-09T09:18:00.750" Score="3" ViewCount="46" Body="&lt;p&gt;I am involved in an experiment in the Bay of Bengal, letting moorings for a year long period and doing ship cruises. We have observed (from mooring CTDs) that the Brunt Vaisala frequency has increased almost by a magnitude of 10^1 during the late Indian monsoon period (September-December). The depth of measurement is 0-100 metres. Year 2016.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Possibility 1: Drifting of instruments and hence wrong measurements?&#xA;Possibility 2: Any process which can create such an increase in stratification.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Possibility 2 is my question. The whole water column shows a similar increasing trend in stratification which kind of negates Possibility 1. So, could you please help with some process insight on the kind of ways this can happen? For some inputs: Bay of Bengal gets very huge amount of fresh water during Monsoons. &lt;/p&gt;&#xA;" OwnerUserId="7478" LastActivityDate="2017-02-09T09:18:00.750" Title="Increase in Stratification late monsoon in Bay of Bengal" Tags="|oceanography|salinity|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9636" PostTypeId="2" ParentId="9618" CreationDate="2017-02-09T14:16:41.013" Score="2" Body="&lt;p&gt;There are many universities and institutions that offer free online course nowadays. They are taught by world-famous leader in the field of the subject. I recently attend this course offer by University of Exeter on Climate change. It is very easy to follow and there is homework and test to do &lt;a href=&quot;https://www.exeter.ac.uk/climatechangecourse/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.exeter.ac.uk/climatechangecourse/&lt;/a&gt; People can get a certificate after they complete the course. &#xA;I recommend you to watch documentary about climate change and read some science magazine which has the latest development on climatology. Visit a science museum and attend some open lectures will definitely help. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of career, you could do a PhD in climate science which has a strong element in biology and ecology in terms of Earth system modeling. This is a email subscription that send you regular advertisement on PhD positions and relevant jobs. &lt;a href=&quot;http://mailman.ucar.edu/mailman/listinfo/es_jobs_net&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://mailman.ucar.edu/mailman/listinfo/es_jobs_net&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Computer programming and data visualization are very important skills you need for climatology. So maybe some courses on how to use R, Python, Matlab, Fortran would also be useful. Hope this helps. &lt;/p&gt;&#xA;" OwnerUserId="7482" LastActivityDate="2017-02-09T14:16:41.013" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9637" PostTypeId="2" ParentId="9528" CreationDate="2017-02-09T14:42:50.770" Score="2" Body="&lt;p&gt;The ozone hole size changes according to the season. It is usually larger in winter because cold temperature &lt;a href=&quot;https://earthscience.stackexchange.com/questions/5162/why-is-the-ozone-layer-hole-more-pronounced-in-the-southern-hemisphere&quot;&gt;Why is the Ozone Layer &amp;#39;hole&amp;#39; more pronounced in the Southern Hemisphere?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And in this graph you can see that the ozone level is lower in Australia, South Africa and south America area. &lt;a href=&quot;http://www.cpc.ncep.noaa.gov/products/stratosphere/sbuv2to/gif_files/sbuv18_sh_latest.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.cpc.ncep.noaa.gov/products/stratosphere/sbuv2to/gif_files/sbuv18_sh_latest.gif&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a broader scale, it does have an impact to the rest of the world. A thinning ozone can cause stratosphere cooling. Scientists are still studying this &lt;a href=&quot;http://www.ucsusa.org/global_warming/science_and_impacts/science/ozone-hole-and-gw-faq.html#.WJx_YLNqPU8&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.ucsusa.org/global_warming/science_and_impacts/science/ozone-hole-and-gw-faq.html#.WJx_YLNqPU8&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="7482" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2017-02-09T14:42:50.770" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9641" PostTypeId="1" CreationDate="2017-02-09T08:14:18.737" Score="2" ViewCount="512" Body="&lt;p&gt;I have $u$-wind, $v$-wind and specific humidity. I would like to compute moisture flux convergence at a grid point. So I need to compute the value of $q(\frac{du}{dx} + \frac{dv}{dy})$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is how to compute $\frac{du}{dx}$ and $\frac{dv}{dy}$ from $u$-wind and $v$-wind at grid point $(x,y)$? &lt;/p&gt;&#xA;" OwnerUserId="3194" OwnerDisplayName="Kay" LastEditorUserId="3194" LastEditDate="2017-02-14T00:50:28.473" LastActivityDate="2017-02-14T00:50:28.473" Title="How to compute the moisture flux convergence at a grid point?" Tags="|meteorology|moisture-flux|" AnswerCount="0" CommentCount="2" ClosedDate="2017-02-10T00:48:48.390" ContentLicense="CC BY-SA 3.0" />
  <row Id="9642" PostTypeId="1" AcceptedAnswerId="9655" CreationDate="2017-02-09T19:50:37.303" Score="12" ViewCount="15199" Body="&lt;p&gt;Ever since the 3rd grade, I've been troubled by the inability to remember if Latitude runs East/West or runs North/South. I would always stress out &lt;strong&gt;BIG TIME&lt;/strong&gt; during my Geography class.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm &lt;strong&gt;much&lt;/strong&gt; older now, and I still have trouble telling them apart... &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;facepalm&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any good tips or tricks to help me remember which direction each runs?&lt;/p&gt;&#xA;" OwnerUserId="7483" LastEditorUserId="192" LastEditDate="2017-02-09T21:13:51.907" LastActivityDate="2020-03-24T23:18:24.963" Title="How to easily remember orientation of latitude and longitude?" Tags="|geography|" AnswerCount="9" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9644" PostTypeId="2" ParentId="9589" CreationDate="2017-02-09T20:47:03.043" Score="6" Body="&lt;p&gt;The white &amp;quot;patina&amp;quot; is most likely some form of opal as you suggest. I did some research and I'll explain how the agate becomes opal and why it's more common in the eroded rock.&#xA;Some background:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;agate and opal are both forms of silica with the chemical formula SiO&lt;sub&gt;2&lt;/sub&gt;&lt;/li&gt;&#xA;&lt;li&gt;opal is a hydrated amorphous form of silica (1)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;You would find the opal more often on weathered and deposited chalcedony because &amp;quot;the polymerization of silica into three-dimensional gel-like networks [opal] is favored in the pH range 3 to 10 where dissolved salts are present in solution.&amp;quot;(2) The pH of stream/river water ranges from 6.5 to 8.5 and all natural water has salts of some kind. (3) Therefore, dissolved silica in stream/river water reacts with the agate and opal grows onto it.&lt;/p&gt;&#xA;&lt;p&gt;To sum up: yes, the &amp;quot;patina&amp;quot; is most likely opal and it forms when stream/river water interacts with the agate.&lt;/p&gt;&#xA;&lt;p&gt;sources:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Opal&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Opal&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://rruff-2.geo.arizona.edu/uploads/CM46_139.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://rruff-2.geo.arizona.edu/uploads/CM46_139.pdf&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.grc.nasa.gov/WWW/k-12/fenlewis/Waterquality.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.grc.nasa.gov/WWW/k-12/fenlewis/Waterquality.html&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Source 2 talks about various types of opal formation, but for simplicity's sake I only mentioned polymerization.&lt;/p&gt;&#xA;" OwnerUserId="7484" LastEditorUserId="2470" LastEditDate="2023-03-06T10:20:41.677" LastActivityDate="2023-03-06T10:20:41.677" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="9645" PostTypeId="2" ParentId="9642" CreationDate="2017-02-09T21:00:11.300" Score="11" Body="&lt;p&gt;The way I remember is pretty simple. When I think of &lt;strong&gt;LAT&lt;/strong&gt;itude I stick my arms out &lt;strong&gt;LAT&lt;/strong&gt;erally (metaphorically or literally). When I think of &lt;strong&gt;LON&lt;/strong&gt;gitude I imagine stretching out a &lt;strong&gt;LON&lt;/strong&gt;g ribbon or something vertically. Also, the &quot;on&quot; sound in longitude stretches your mouth vertically. To be fair you just have to remember one and then you know the other one. Hopefully this helps.&lt;/p&gt;&#xA;" OwnerUserId="7484" LastEditorUserId="200" LastEditDate="2017-02-09T21:05:41.347" LastActivityDate="2017-02-09T21:05:41.347" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9647" PostTypeId="1" AcceptedAnswerId="9654" CreationDate="2017-02-09T23:22:33.310" Score="5" ViewCount="3235" Body="&lt;p&gt;If there were an earthquake that somehow cause a crack in the earth and allowed a significant amount of magma to flow into a very large oil deposit. With that high amount of explosive energy that would be produced, could it cause an earthquake or even a volcano? Does this usually happen?&lt;/p&gt;&#xA;" OwnerUserId="7486" LastActivityDate="2017-02-10T12:12:45.367" Title="What would happen if magma flows into a very large oil deposit?" Tags="|volcanology|earthquakes|petroleum|gas|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9648" PostTypeId="2" ParentId="4574" CreationDate="2017-02-10T03:37:40.173" Score="5" Body="&lt;p&gt;Atmospheric oxygen is not in an equilibrium of 21%, it just changes very slowly.  For instance, oxygen has &lt;a href=&quot;http://www.livescience.com/56219-earth-atmospheric-oxygen-levels-declining.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;decreased by 0.7% over the past 800 thousand years&lt;/a&gt;, likely due to increased erosion (which exposes more rock that can be oxidized) and cooler oceans (which can then absorb more oxygen). So, while it is a slow process on geologic timescales, the amount of atmospheric oxygen does vary and is not in true equilibrium. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oxygen was not abundant in the Earth's early atmosphere and it is chemically reactive so it can be difficult to accumulate.  It was mainly created by lifeforms and was only able to accumulate significantly over geologic time for a few reasons:  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Most of the hydrogen in the atmosphere has escaped, so oxygen doesn't easily react in the atmosphere&lt;/li&gt;&#xA;&lt;li&gt;decreases in volcanic activity (which produce sulfur that can react with oxygen) also allow more accumulation of oxygen.  &lt;/li&gt;&#xA;&lt;li&gt;once there was enough oxygen to allow the ozone layer to form, more lifeforms were able to develop which were able to produce more oxygen&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;It is important to note that the idea of a negative feedback has been postulated before.  Namely, that wildfire could limit the maximum atmospheric oxygen possible.  Since combustion occurs more easily in high oxygen environments, the idea was that if atmospheric oxygen levels increased much more than 21%, wildfire occurrences would be extreme enough to burn up the excess oxygen (and thereby reduce oxygen production from trees).  However, there is evidence that atmospheric oxygen was up to 35% in the late paleozoic era, which doesn't support the idea of wildfire as a negative feedback mechanism.  Furthermore, &lt;a href=&quot;https://www.fs.fed.us/ne/newtown_square/publications/other_publishers/OCR/ne_2004_wildman001.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt; by Wildman et al., says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Theoretical models suggest that atmospheric oxygen reached&#xA;  concentrations as high as 35% O2 during the past 550 m.y. Previous&#xA;  burning experiments using strips of paper have challenged&#xA;  this idea, concluding that ancient wildfires would have decimated&#xA;  plant life if O2 significantly exceeded its present level of 21 %. New&#xA;  thermochemistry and flame-spread experiments using natural fuels&#xA;  contradict these results and indicate that sustained burning of forest&#xA;  fuels at moisture contents common to living plants does not&#xA;  occur between 21% and 35% 02. Therefore, the fires under atmospheres&#xA;  with high oxygen concentrations would not have prevented&#xA;  the persistence of plant communities. Times of high O2 also&#xA;  agree with observations of concurrent fire-resistant plant morphology,&#xA;  large insects, and high concentrations of fossil charcoal. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2017-02-11T02:26:22.157" LastActivityDate="2017-02-11T02:26:22.157" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9649" PostTypeId="2" ParentId="9642" CreationDate="2017-02-10T03:47:38.873" Score="5" Body="&lt;p&gt;I had the same problem.  What seemed to set them firmly apart was the connection to a &lt;strong&gt;LADDER&lt;/strong&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ladder jives with the word latitude.  So the lines of latitude are like climbing the rungs of a ladder.  And the values of latitude are how high up (or down) you are.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Generally I just go with that, it automatically defines the other term... but if you do want to go further with longitude, I agree that using terms with LONG do the job.  To get the longitude, you go &lt;strong&gt;ALONG&lt;/strong&gt; the rungs &lt;strong&gt;LONGWAYS&lt;/strong&gt;.  The vertical lines are the hashmarks to show how far you've come along.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm convinced in my years thinking about this personally and then teaching that a big part of the challenge of any imagery/phrases is the confusion between whether you're talking about the line itself or values.  It surely confused me to no end that values of latitude were north/south, while the lines of latitude were drawn east-west.  I think/hope the ladder/latitude connection is a clear way to help people of all ages overcome the confusion.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2017-02-10T03:47:38.873" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9650" PostTypeId="1" CreationDate="2017-02-10T05:44:02.800" Score="3" ViewCount="621" Body="&lt;p&gt;I have heard it said that if there are 2 hurricanes with the same maximum wind speed, and one has a bigger eye while the other a smaller eye, then the one with the smaller eye would have a lower central pressure.  Is this true?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="6298" LastEditDate="2017-02-10T07:03:44.013" LastActivityDate="2017-04-12T16:05:03.350" Title="Does a hurricane with a smaller eye have a lower pressure?" Tags="|tropical-cyclone|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9651" PostTypeId="1" CreationDate="2017-02-10T08:07:54.343" Score="5" ViewCount="1086" Body="&lt;p&gt;What is the difference between linear airy wave theory and 5th order Stokes wave theory? What is the differences in terms of application. I am looking more on offshore structure analysis aspects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks.&lt;/p&gt;&#xA;" OwnerUserId="7488" LastEditorUserId="2470" LastEditDate="2018-07-13T09:18:13.173" LastActivityDate="2018-07-13T09:18:13.173" Title="Differences between linear airy wave theory and Stokes' 5 wave theory? and it's application" Tags="|oceanography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="9652" PostTypeId="2" ParentId="9647" CreationDate="2017-02-10T09:11:13.123" Score="5" Body="&lt;p&gt;An oil deposit is gravel and rock mixed with oil, capped by rock - like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BTHvr.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BTHvr.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My &lt;em&gt;guess&lt;/em&gt; is that if somehow, likely from below or sideways, magma would intrude into this deposit, oil (and posibly water) would evaporate. The pressure rises, slowing the magma intrusion. If enough magma and enough heat is provided, the vapor pressure of the oil may be enough to crack the rock layer at places, oil would escape and condense in the shale layer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My gut feeling is that we are talking about processes that take years to decades to play out.&lt;/p&gt;&#xA;" OwnerUserId="117" LastActivityDate="2017-02-10T09:11:13.123" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9654" PostTypeId="2" ParentId="9647" CreationDate="2017-02-10T12:12:45.367" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;If there were an earthquake that somehow cause a crack in the earth and allowed a significant amount of magma to flow into a very large oil deposit.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My understanding from this is that you are making two assumptions, which are not necessarily true:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;That earthquakes open cracks allowing magma to flow. It may actually the other way around: when magma flows, it cracks rocks under pressure, causing minor earthquakes. Large earthquakes, from the kind that destroys things and kills people, are usually unrelated to magmas.&lt;/li&gt;&#xA;&lt;li&gt;That there is magma everywhere underneath the crust, and it's deeper than oil deposits. Again, not necessarily true. The overwhelming majority of the crust and the mantle are solid. There are localised areas where melting occurs (the location of active volcanos is a sign of that). Usually, these locations are not where oil deposits occur. And even then, magma chambers can be very close to the surface. In some cases about 1 km below the surface or less. Oil deposits can be several km deep.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;That said, what will happen if it does actually happen?&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;With that high amount of explosive energy that would be produced, could it cause an earthquake or even a volcano?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not really. Injecting magma into oil may cause some of it to boil or evaporate, causing expansion and possibly fracturing. But the magma is already fracturing the rock anyway. The oil itself is not going to burn or explode, because this requires oxygen that is not readily available underground. The oil can reduce the iron in the magma, thus being oxidised to CO&lt;sub&gt;2&lt;/sub&gt; (&lt;a href=&quot;https://en.wikipedia.org/wiki/Disko_Island#Geology&quot; rel=&quot;noreferrer&quot;&gt;and forming metallic iron&lt;/a&gt;). This is probably not going to make much of a difference if the oil was decomposed to methane, which is another gas. This might ignite if carried to the surface with the magma, but I doubt that it's going to do anything more spectacular the magma itself will.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Does this usually happen?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-02-10T12:12:45.367" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9655" PostTypeId="2" ParentId="9642" CreationDate="2017-02-10T12:20:47.420" Score="12" Body="&lt;p&gt;I also mixed &lt;strong&gt;Longitude&lt;/strong&gt; and &lt;strong&gt;Latitude&lt;/strong&gt; until I heard someone saying '&lt;em&gt;... at high latitudes.&lt;/em&gt;' in a conference talk.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In my mind, the picture of the Earth shows the Earth with the North and South poles at the top and bottom (or reversed, doesn't matter). &lt;em&gt;High&lt;/em&gt; describes a vertical orientation. Therefore, the &lt;strong&gt;latitude&lt;/strong&gt; changes in &lt;strong&gt;North-South&lt;/strong&gt; direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, because the horizontal degree scale has a discontinuity at 360 degree (0 degree), it does not make much sense to distinguish &lt;em&gt;high&lt;/em&gt; and &lt;em&gt;low&lt;/em&gt; values in horizontal direction. Hence, &lt;strong&gt;high&lt;/strong&gt; values are in &lt;strong&gt;vertical direction&lt;/strong&gt; (&lt;strong&gt;= latitude&lt;/strong&gt;).&lt;/p&gt;&#xA;" OwnerUserId="5594" LastEditorUserId="5594" LastEditDate="2017-02-10T13:27:42.927" LastActivityDate="2017-02-10T13:27:42.927" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9656" PostTypeId="1" CreationDate="2017-02-10T17:22:30.393" Score="4" ViewCount="445" Body="&lt;p&gt;By my reading of the wikipedia page on the Trewartha climate classification, climate classifications are not mutually exclusive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's take a look at the climate classification of Iowa City, IA.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Trewartha precipitation limit is defined as 10(T-10)+3P, where T is the mean annual temperature and P is the percentage of the annual precipitation occurring in the six high-sun months. In the northern hemisphere, this is Apr—Sep.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.weatherbase.com/weather/weather.php3?s=97037&amp;amp;cityname=Iowa-City-Iowa-United-States-of-America&amp;amp;units=us&quot; rel=&quot;nofollow noreferrer&quot;&gt;Using the data publicly available on weatherbase.com&lt;/a&gt;, the Trewartha precipitation limit is 608.23 mm. Twice that is 1216.46 mm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;BW (desert) climates are defined by mean annual precipitation below the original threshold (608.23 mm for Iowa City), BS (steppe) climates are defined by mean annual precipitation above the original threshold but less than twice the threshold (1216.46 mm for Iowa City), and if mean annual precipitation exceeds twice the threshold then the climate is not classified as B (dry). Iowa City's mean annual precipitation is 922.2 mm, earning it a BS (steppe) classification.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, Iowa City also satisfies the definition of a Dca (hot-summer continental) climate under the Trewartha climate classification:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;4-7 months with mean monthly temperature above 50 degrees (F). Iowa City has 7 (all of Apr—Oct)&lt;/li&gt;&#xA;&lt;li&gt;Coldest monthly mean temperature below 32 degrees (F). Iowa City's is 22.1 degrees (F) in Jan.&lt;/li&gt;&#xA;&lt;li&gt;Warmest monthly mean temperature above 72 degrees (F). Iowa City's is 74.8 degrees (F) in Jul.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The question is...under the Trewartha climate classification, is Iowa City, IA classified as a BS (steppe) climate, a Dca (hot-summer continental) climate, or both?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE&lt;/strong&gt;: It's come to my attention that I incorrectly used Fahrenheit instead of Celsius for the mean annual temperature, and that Iowa City, IA therefore does not actually lie within a BS (steppe) climate zone. I'm going to leave the original question, though: what happens when a climate meets the criteria for more than one zone?&lt;/p&gt;&#xA;" OwnerUserId="7493" LastEditorUserId="7493" LastEditDate="2017-02-12T13:00:45.540" LastActivityDate="2017-02-12T13:00:45.540" Title="Trewartha climate classification overlap?" Tags="|climate|temperature|models|measurements|earth-observation|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9657" PostTypeId="1" CreationDate="2017-02-10T19:42:58.983" Score="3" ViewCount="297" Body="&lt;p&gt;In the Greenland Sea or in Denmark's strait, near greenland's cost, &lt;a href=&quot;https://i.stack.imgur.com/WOChS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WOChS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;how can I find weather information for this place? Specifically, with respect to months (i.e, dec-feb, march-may, june-august, oct - nov). When it is warmest, coldest, etc.&lt;/p&gt;&#xA;" OwnerUserId="7495" LastActivityDate="2017-02-26T19:23:38.420" Title="How can I find weather data for greenland sea during the 4 seasons?" Tags="|meteorology|" AnswerCount="6" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9658" PostTypeId="2" ParentId="9642" CreationDate="2017-02-10T20:22:00.927" Score="4" Body="&lt;p&gt;One way is to picture a long neck dinosaur. It's a bit of an unconventional connection, but the oddness is what helps me to remember it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ldgOF.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ldgOF.jpg&quot; alt=&quot;Plateosaurus&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(The Editors of Encyclopædia Britannica. &quot;Plateosaurus.&quot; Encyclopædia Britannica. Encyclopædia Britannica, Inc., 25 May 2010. Web.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Longitude: A &lt;strong&gt;LONG&lt;/strong&gt; neck dinosaur has a long neck that extend vertically upwards. The lines of longitude extend vertical on a map of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Latitude: The back of a long neck dinosaur is relatively F&lt;strong&gt;LAT&lt;/strong&gt;. The lines of latitude lay horizontal or &quot;flat&quot; on a map of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;TLDR; F&lt;strong&gt;LAT&lt;/strong&gt; back, &lt;strong&gt;LONG&lt;/strong&gt; neck. I hope this helps.&lt;/p&gt;&#xA;" OwnerUserId="7307" LastEditorUserId="7401" LastEditDate="2017-02-11T06:54:00.737" LastActivityDate="2017-02-11T06:54:00.737" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9659" PostTypeId="2" ParentId="9657" CreationDate="2017-02-10T21:18:55.077" Score="5" Body="&lt;p&gt;An interactive website called &lt;a href=&quot;https://earth.nullschool.net/#current/wind/surface/level/orthographic=-23.26,63.63,405&quot; rel=&quot;noreferrer&quot;&gt;earth&lt;/a&gt; has detailed weather data for the entire globe. Using this is similar to using Google Earth. You can adjust it for almost any weather data you need by clicking the &quot;earth&quot; icon and adjusting the date under each section. You can see the numerical data for a specific area by clicking the area on the globe with your mouse.&lt;/p&gt;&#xA;" OwnerUserId="7307" LastActivityDate="2017-02-10T21:18:55.077" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9660" PostTypeId="2" ParentId="9657" CreationDate="2017-02-10T23:35:25.077" Score="3" Body="&lt;p&gt;You can try the CFSR, a model reanalysis of climate, from 1979 to 2010, or you could use model data, such as the GFS for more recent data inquiries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;CFSR: &lt;a href=&quot;ftp://nomads.ncdc.noaa.gov/CFSR/HP_time_series/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ftp://nomads.ncdc.noaa.gov/CFSR/HP_time_series/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;GFS: &lt;a href=&quot;ftp://nomads.ncdc.noaa.gov/GFS/Grid4&quot; rel=&quot;nofollow noreferrer&quot;&gt;ftp://nomads.ncdc.noaa.gov/GFS/Grid4&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data is in a very raw format (called grib/grib2), that I'd do some research on before you use this data.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-02-10T23:35:25.077" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9661" PostTypeId="2" ParentId="9642" CreationDate="2017-02-11T04:53:05.663" Score="2" Body="&lt;p&gt;I remember &lt;strong&gt;long&lt;/strong&gt;itude it by the fact that it runs the &lt;strong&gt;long&lt;/strong&gt; way around the earth. In other words all longitudes are diameters. &lt;/p&gt;&#xA;" OwnerUserId="4685" LastActivityDate="2017-02-11T04:53:05.663" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9663" PostTypeId="2" ParentId="9642" CreationDate="2017-02-11T05:37:53.703" Score="6" Body="&lt;p&gt;When you say the first syllable of the word &quot;LAtitude&quot; your mouth widens horizontally.   Latitudinal lines also stretch horizontally across the earth (west to east).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you say the first syllable of the word &quot;LOngitude&quot;, your mouth stretches open vertically.  Longitudinal lines also stretch vertically across the earth (south to north).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZO6d6.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZO6d6.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-02-11T05:37:53.703" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9664" PostTypeId="2" ParentId="9657" CreationDate="2017-02-11T07:11:02.127" Score="1" Body="&lt;p&gt;The WorldClimate website appears to offer some climate details from a variety of data sources in a rather digestible format.  It gives details on the sources for each bit of information, which you may well want to dig into deeper to verify the data is reasonably reliable/representative.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To find locations, it seems the best options may be to search the data manually over your region of interest.  Start from an address like &lt;a href=&quot;http://www.worldclimate.com/cgi-bin/grid.pl?gr=N65W037&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.worldclimate.com/cgi-bin/grid.pl?gr=N65W037&lt;/a&gt;, then use the directional controls on the page (or change the URL manually) until you hit other sites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or, alternatively, you search for known site names (unfortunately not just country names :-/) on the &lt;a href=&quot;http://www.worldclimate.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;WorldClimate main page&lt;/a&gt; to see if you get hits.&#xA;&lt;a href=&quot;http://weather.rap.ucar.edu/surface/stations.txt&quot; rel=&quot;nofollow noreferrer&quot;&gt;This&lt;/a&gt; list of current reporting station details at UCAR should give some useful possibilities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Doing that, and trying to estimate from your map, it appears &lt;a href=&quot;http://www.worldclimate.com/cgi-bin/grid.pl?gr=N65W037&quot; rel=&quot;nofollow noreferrer&quot;&gt;Angmagssalik&lt;/a&gt; (&lt;a href=&quot;https://www.google.com/maps/place/65%C2%B035&amp;#39;00.0%22N+37%C2%B037&amp;#39;00.0%22W/@65.5833333,-46.5815104,5z/data=!4m5!3m4!1s0x0:0x0!8m2!3d65.5833333!4d-37.6166667&quot; rel=&quot;nofollow noreferrer&quot;&gt;location&lt;/a&gt;) and &lt;a href=&quot;http://www.worldclimate.com/cgi-bin/grid.pl?gr=N76W018&quot; rel=&quot;nofollow noreferrer&quot;&gt;Danemarkshavn&lt;/a&gt; (&lt;a href=&quot;https://www.google.com/maps/place/76%C2%B046&amp;#39;00.0%22N+18%C2%B040&amp;#39;00.0%22W/@76.0010296,-36.5963542,4z/data=!4m5!3m4!1s0x0:0x0!8m2!3d76.7666667!4d-18.6666667&quot; rel=&quot;nofollow noreferrer&quot;&gt;location&lt;/a&gt;) may be your best bets for the info you wish for.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2017-02-11T07:11:02.127" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9665" PostTypeId="1" AcceptedAnswerId="9666" CreationDate="2017-02-11T11:05:50.787" Score="8" ViewCount="534" Body="&lt;p&gt;What kind of tectonic plate activity exists on other planets in the solar system, or even large moons? Are there any deeper studies of what is needed for a planet or large moon to have tectonic activity, and how that activity might differ from planet/moon to planet/moon?&lt;/p&gt;&#xA;" OwnerUserId="5870" LastActivityDate="2017-02-12T00:19:03.457" Title="How do tectonics work on other planets?" Tags="|plate-tectonics|planetary-science|tectonics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9666" PostTypeId="2" ParentId="9665" CreationDate="2017-02-11T13:29:14.317" Score="7" Body="&lt;p&gt;It's a huge field of research and a lot of interesting studies have been published over the years, but also a lot of speculation. Models and theories are mostly based on surface structures observed by remote sensing. Potential field data, as gravimetry can also add good constraints when available. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tectonic forces might be rather common in large young planets, but as they cool the process usually stops. In our time and solar system, plate tectonics as we would recognize it, is only known on Earth (and maybe Titan). Other tectonic forces can cause similar features by local uplifts, volcanism and &lt;a href=&quot;https://en.wikipedia.org/wiki/Cryovolcano&quot; rel=&quot;noreferrer&quot;&gt;cryovolcanism&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Geology_of_Venus#Tectonic_activity&quot; rel=&quot;noreferrer&quot;&gt;Venus&lt;/a&gt; appears to have some kind of tectonic forces, at least in the past. An important part of the present research focus on the dynamics and chemistry of the Venusian mantle and how the &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2012JE004237/abstract&quot; rel=&quot;noreferrer&quot;&gt;topography&lt;/a&gt; helps us understand the development of the planet. The &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/92JE01418/full&quot; rel=&quot;noreferrer&quot;&gt;data&lt;/a&gt; from &lt;a href=&quot;https://en.wikipedia.org/wiki/Magellan_(spacecraft)&quot; rel=&quot;noreferrer&quot;&gt;Magellan&lt;/a&gt; in the early 90's are particularly important. Studies of Venus also helps us to understand how tectonics developed on Earth. It's been suggested that lack of water as a lubricant in the Venusian upper mantle makes continental drift impossible, but mantle dynamics can still cause local/regional uplift and volcanism. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Europa_(moon)&quot; rel=&quot;noreferrer&quot;&gt;Europa&lt;/a&gt; is also supposed to have an odd kind stress that resembles tectonics, but caused by the tidal force from Jupiter that deforms the moon. We have the same tidal deformation on Earth, but it is much stronger on Europa and can cause dynamics that mix the interior. Somehow similar to how one should roll and press a lemon before cutting it to squeeze out the juice. &lt;a href=&quot;https://en.wikipedia.org/wiki/Galileo_(spacecraft)&quot; rel=&quot;noreferrer&quot;&gt;Galileo&lt;/a&gt; is the main source of data, still. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Titan_(moon)#Cryovolcanism_and_mountains&quot; rel=&quot;noreferrer&quot;&gt;Titan&lt;/a&gt; could be the candidate that most resemble Earth, but it's under debate and more data is needed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reasons to have plate tectonic on a planet are complicated and debated. I wouldn't say that we even have a good understanding of the continental drift on Earth yet. The best approach to understand what is needed for tectonism is to look at the planets energy budget, how much heat is generated and how can it leave the planets internal system. The chemistry of the mantel is also important, some dishes boil, other dishes fry. Water or other fluids appears to be crucial. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0031018206000289&quot; rel=&quot;noreferrer&quot;&gt;A rather interesting suggestion&lt;/a&gt; for Earth's unique plate tectonics is that it depends on additional energy harvested by the photosynthesis in green plants. It might be that life is the cause of mountains instead of the other way around. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-02-12T00:19:03.457" LastActivityDate="2017-02-12T00:19:03.457" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9667" PostTypeId="1" AcceptedAnswerId="10195" CreationDate="2017-02-11T16:47:51.730" Score="8" ViewCount="318" Body="&lt;p&gt;Occasionally, I go out with my camera and tripod and capture cumulonimbus clouds from distance. Sometimes I am worried when I hear thunder that I could be hit by a lightning bolt. I have seen several &quot;bolts out of a clear blue sky&quot; and it reminds me of the danger (even though the probability is probably small).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Koac9.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Koac9.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;Photography by ©Jeff Miles&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A nice example of lightning comming out of cumulonimbus anvil - I've heard that you can even be hit hundreds of kilometres away (but it's extremely unlikely).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, I know that during thunderstorms it is very dangerous just to stay in contact with metals or water. This is why I never go out (or open windows) when I take photos of lightning from my flat. But... I have seen several amazing captures of lightning by storm chasers. How is it that they are so close to lightning, but do not get struck? Is there any trick or are they simply risking their lives?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Six36.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Six36.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've considered how lightning strikes, and drew this image.  In this situation it seems that there are three possible targets. I drew a radius around each object because it my intuition suggests it would work like this.  If so, then the building on top of the hill has the highest probability of being struck.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the lightning bolt hits the object closest to its path, could we completely protect ourselves from being struck by staying RELATIVELY close to some much taller objects, so that they would cover the sky around us with their large radius?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to stay in safe, but take some beautiful photos of lightning too.  I know everyone says that &quot;during lightning storms you should never stand under trees&quot;. But if located right, can you actually be protected from danger like this?  Or what practices are truly the best way to stay safe while photographing lightning storms?&lt;/p&gt;&#xA;" OwnerUserId="7031" LastEditorUserId="6298" LastEditDate="2017-02-13T05:48:25.103" LastActivityDate="2017-04-27T04:11:30.037" Title="What is the best way to stay safe while photographing lightning storms?" Tags="|meteorology|lightning|storms|thunderstorm|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="9668" PostTypeId="2" ParentId="1060" CreationDate="2017-02-12T02:37:09.307" Score="-1" Body="&lt;p&gt;Convert infrared energy to matter. Reduces atmospheric temperature. Or pass atmospheric infrared light through Bose-Einstein condensate, and as it loses momentum, the system reduces temperature (decrease in kinetic energy due to momentum loss).&lt;/p&gt;&#xA;" OwnerUserId="7499" LastEditorDisplayName="user1161" LastEditDate="2017-06-12T22:53:06.607" LastActivityDate="2017-06-12T22:53:06.607" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9669" PostTypeId="1" CreationDate="2017-02-12T05:49:32.860" Score="5" ViewCount="857" Body="&lt;p&gt;I've been curious about if there are any gases in the atmosphere that are nearly transparent to both solar and thermal radiation. CO&lt;sub&gt;2&lt;/sub&gt; for instance is nearly transparent to solar radiation but is partially opaque to thermal.&lt;/p&gt;&#xA;&lt;p&gt;I've tried to find information on the internet, but the large amount of information about global warming is effectively hijacking my google searches.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt; When I say solar radiation, I am not just referring to that which is visible. Please consider at least infrared, visible, and UV in your answer.&lt;/p&gt;&#xA;&lt;p&gt;Any help or insight will be greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="7500" LastEditorUserId="2470" LastEditDate="2021-08-08T17:06:20.577" LastActivityDate="2021-08-08T17:16:26.597" Title="Gases that are nearly transparent to solar AND thermal radiation?" Tags="|atmosphere|atmospheric-radiation|gas|" AnswerCount="4" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="9670" PostTypeId="1" CreationDate="2017-02-12T11:52:34.780" Score="3" ViewCount="131" Body="&lt;p&gt;The Hawaiian Islands are formed by volcanic activity over a hotspot in the Earth's mantle. What is the shape of this hotspot in the mantle? Is it like a pyramid or a pillar or an upside-down pyramid?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="6298" LastEditDate="2017-02-12T19:15:45.263" LastActivityDate="2017-02-12T19:15:45.263" Title="What is the structure of the hot spot under Hawaii?" Tags="|mantle|mantle-plumes|hotspot|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9671" PostTypeId="1" AcceptedAnswerId="9672" CreationDate="2017-02-12T14:57:42.350" Score="2" ViewCount="3467" Body="&lt;p&gt;I want to know if large earthquakes can happen twice in the same place? I live in Istanbul/Turkey. In Canakkale/Turkey too many earthquakes happen for days! I know it is normal for this region but 4.8 , 4.9 , 5.0 , 5.3 etc. is this a normal thing? I'm not saying &quot;months&quot;, every day atleast one earthquake...(In Richter Scale)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this OK? or not? &lt;/p&gt;&#xA;" OwnerUserId="7502" LastActivityDate="2023-08-05T19:09:09.473" Title="Can large earthquakes happen few times at same place(in days)" Tags="|seismology|earthquakes|seismic|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9672" PostTypeId="2" ParentId="9671" CreationDate="2017-02-12T15:46:08.740" Score="2" Body="&lt;p&gt;Yes, and they are quite common, they are called &lt;a href=&quot;https://en.wikipedia.org/wiki/Aftershock&quot; rel=&quot;nofollow noreferrer&quot;&gt;aftershocks&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;An earthquake redistributes the stress that creates the quake across the fault line, which then creates new points of stress, which result in additional earthquakes, which further redistribute the stress again, and so on and so forth until all the energy is spent. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.scsn.org/index.php/earthquakes/earthquake-swarms/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earthquake swarms&lt;/a&gt; also exist.  They basically work on the same principle as aftershocks but are much stronger. They tend to occur in places where you have many faults in the same region.  The release of pressure on one fault causes movement that puts more stress on other faults, causing a cascade of quakes. California and other transform faults are famous for them. Here is rather nice BBC film about them.  &lt;a href=&quot;http://www.dailymotion.com/video/x2262rz_bbc-horizon-2003-earthquake-storms_shortfilms&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.dailymotion.com/video/x2262rz_bbc-horizon-2003-earthquake-storms_shortfilms&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="6298" LastEditDate="2017-02-13T06:11:34.827" LastActivityDate="2017-02-13T06:11:34.827" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9673" PostTypeId="1" CreationDate="2017-02-12T16:05:02.233" Score="2" ViewCount="175" Body="&lt;p&gt;Why and what could be the reasons for flexible buildings that are far from the epicenter of an earthquake being more sensitive to damage than those located near it.&lt;/p&gt;&#xA;" OwnerUserId="7513" LastEditorUserId="2470" LastEditDate="2022-08-03T01:08:28.330" LastActivityDate="2022-08-03T01:08:28.330" Title="Why would sensitive buildings, further away from the earthquake epicenter, be the ones that suffer more damage than those close to it?" Tags="|seismic-hazards|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="9674" PostTypeId="1" CreationDate="2017-02-12T17:28:12.877" Score="11" ViewCount="26488" Body="&lt;p&gt;We see stones and they appear to be the same throughout our life time. Mountains also appear to not significantly change. So do mountains and stones decompose? What is the life span of a stone? After it alters, what does it turn into?&lt;/p&gt;&#xA;" OwnerUserId="7504" LastEditorDisplayName="user20559" LastEditDate="2021-05-26T14:05:06.190" LastActivityDate="2021-05-26T14:05:06.190" Title="How long does it take for a stone to alter?" Tags="|geology|rocks|erosion|weathering|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="9675" PostTypeId="1" CreationDate="2017-02-12T17:39:10.263" Score="5" ViewCount="505" Body="&lt;p&gt;I'm a global warming skeptic, and one of my concerns is the accuracy of historical global temperatures. Since these temperatures weren't sampled at random locations or gridded points, can they be considered an accurate representation of &quot;global temperature&quot;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thoughts/etc:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3982162/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3982162/&lt;/a&gt; talks about this in a temporal sense, since using the average of the minimum and maximum daily temperatures at a given location isn't really a great way of determining average temperature. However, it doesn't discuss geographical random sampling/gridding.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/joc.4580/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://onlinelibrary.wiley.com/doi/10.1002/joc.4580/full&lt;/a&gt; notes this problem exists, and takes uniformly gridded measurements, but it's limited to a specific region and time period (1979-2012).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;I know climate scientists slice the Earth up into grids to avoid clustering bias, but that's not the same thing, and isn't useful if the original readings don't accurately represent the slice/region.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;I also realize that climate scientists have other measures of global warming, but linear regression of actual temperature measurements seems to be the most used to convince the public, so their accuracy seems important.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;As a skeptic, I'd also like to know if, in general, most of the arguments for global warming are statistical in nature (ie, linear regression on measured variables), or the statistical ones are just the most &quot;photogenic&quot; for public consumption? In other words, is the whole non-randomly-sampled/gridded temperature argument a red herring?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;EDIT (to clarify question):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To determine the Earth's mean surface temperature, we can employ one of these methods:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Measure the Earth's temperature at every point and average. Of course, this is physically impossible, since a point is a 0-dimensional mathematical abstraction, but we can do something close with satellites.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Select a large number of random points on the Earth's surface (this random distribution is uniform in longitude, but not in latitude-- in latitude, it would look like a cosine curve), measure the temperature, and average. In addition to giving us a mean, it would give us a standard deviation so we can say &quot;we are 95% confident that the Earth's true mean temperature is X plus or minus Y&quot;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Take a uniformly spaced grid (non trivial, since the distance between longitudes vary by latitude), measure the temperature at those points and average. This is similar to the first approach, but with fewer points. Unless we believe our grid points introduce a bias, this should be as accurate as random sampling.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;My problem: temperature measurements in the past were made using NONE of these methods. The points where temperature was measured were not chosen randomly or in a gridded fashion. Therefore, how can they be an accurate measurement of historical temperature, even if we only consider temperature changes?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NOTE: I realize surface temperature isn't the best measure of global warming, since water has a much higher specific heat than land (among other things), but that's my focus for this question.&lt;/p&gt;&#xA;" OwnerDisplayName="user967" LastEditorDisplayName="user967" LastEditDate="2017-02-15T04:05:51.897" LastActivityDate="2017-07-14T08:01:19.837" Title="Is non-randomly-sampled historical data representative?" Tags="|climate-change|" AnswerCount="2" CommentCount="25" ContentLicense="CC BY-SA 3.0" />
  <row Id="9676" PostTypeId="1" AcceptedAnswerId="9686" CreationDate="2017-02-12T17:17:52.807" Score="9" ViewCount="663" Body="&lt;p&gt;I just read &lt;a href=&quot;https://www.nytimes.com/2016/01/12/science/midocean-ridges-volcano-underwater.html&quot;&gt;this article&lt;/a&gt; and was astonished to see the following:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Oceanographers stumbled on [the mid-oceanic ridges'] volcanic nature in 1973.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What I find surprising is how &lt;em&gt;recent&lt;/em&gt; that is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Considering that&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the &lt;a href=&quot;http://www.historyworld.net/wrldhis/PlainTextHistories.asp?historyid=aa77&quot;&gt;history of geology&lt;/a&gt; in general goes back at least 3 or 4 centuries&lt;/li&gt;&#xA;&lt;li&gt;the study of plate tectonics &lt;a href=&quot;http://www.ucmp.berkeley.edu/geology/techist.html&quot;&gt;goes back to 1912&lt;/a&gt; (even though it took a few more decades to gain wide acceptance)&lt;/li&gt;&#xA;&lt;li&gt;oceanic ridges were known at least &lt;a href=&quot;https://en.wikipedia.org/wiki/Mid-Atlantic_Ridge&quot;&gt;as early as 1872&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;the correlation between &lt;a href=&quot;http://www.geology.sdsu.edu/how_volcanoes_work/Volcano_tectonic.html&quot;&gt;seismic activity and volcanoes&lt;/a&gt; has been known for some time (I don't know exactly how long, but &lt;em&gt;certainly&lt;/em&gt; the Romans felt the ground shaking when Vesuvius' erupted)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Then my question is, with regards to the (seemingly unusually) recent date quoted in the above article:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Why did the discovery of volcanic activity at sub-oceanic plate boundaries take so long?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="7505" OwnerDisplayName="pr1268" LastEditorUserId="6298" LastEditDate="2017-02-12T21:54:50.567" LastActivityDate="2017-02-13T20:58:33.160" Title="Why did it take so long to discover the volcanic nature of mid-oceanic ridges?" Tags="|volcanology|earthquakes|history-of-science|ocean-ridge|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9679" PostTypeId="2" ParentId="9674" CreationDate="2017-02-12T22:32:08.393" Score="13" Body="&lt;p&gt;Mountains and rock do decompose or weather into sediment.  &lt;a href=&quot;http://www.cotf.edu/ete/modules/msese/earthsysflr/rock.html&quot; rel=&quot;noreferrer&quot;&gt;A basic rock cycle overview&lt;/a&gt; shows the possible pathways between all three rock types (igneous, metamorphic, and  sedimentary) how one type can be transformed into another. After a rock is weathered into sediment, that sediment can become a rock again.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Weathering rates of rock vary widely regional based on the following factors:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Mineral composition of the rock  (some minerals are less stable at surface conditions than others)&lt;/li&gt;&#xA;&lt;li&gt;Amount of plant life growing on the rocks and mountains. (Plant roots can be powerful chemical and physical weathering agent)&lt;/li&gt;&#xA;&lt;li&gt;Amount of precipitation (Chemical dissolution due to rainfall is a significant weathering factor for some rock types (carbonate rocks)&lt;/li&gt;&#xA;&lt;li&gt;Seasonal freezing periods.  (Ice expansion in cracks and fractures can weaken rocks over very short periods of time.&lt;/li&gt;&#xA;&lt;li&gt;Temperature range of the region.  (I believe diurnal temperature differentials specially in high mountain deserts has a specific weather impact on some rock types).&lt;/li&gt;&#xA;&lt;li&gt;Local earthquakes and volcanic activity.&lt;/li&gt;&#xA;&lt;li&gt;Erosion due to water (streams, rivers, lakes, and oceans).&lt;/li&gt;&#xA;&lt;li&gt;Erosion due to glaciers and ice flows.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;You can get an estimate of weathering rates of different rock types for a local region by careful examination of &lt;a href=&quot;http://deimos3.apple.com/WebObjects/Core.woa/DownloadTrackPreview/psu.edu.1649623081.01661536524.1661600062.pdf&quot; rel=&quot;noreferrer&quot;&gt;cemetery gravestones&lt;/a&gt;.  &lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="2470" LastEditDate="2017-02-13T07:21:04.370" LastActivityDate="2017-02-13T07:21:04.370" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9682" PostTypeId="1" AcceptedAnswerId="12105" CreationDate="2017-02-13T04:25:31.450" Score="9" ViewCount="140" Body="&lt;p&gt;At the time of this post, there was urgent danger of &lt;a href=&quot;http://www.mercurynews.com/2017/02/12/oroville-residents-told-to-evacuate-spillway-failure-imminent/&quot; rel=&quot;noreferrer&quot;&gt;spillway failure at the Oroville Dam&lt;/a&gt; in California, with evacuations in place for hundreds of thousands, and even larger populations further downstream in the Sacramento metro area.  There's &lt;a href=&quot;https://www.internationalrivers.org/questions-and-answers-about-large-dams&quot; rel=&quot;noreferrer&quot;&gt;300 large dams&lt;/a&gt; in the world.  So it would seem quite useful to have a method to quickly estimate how quickly a large flood might move downstream.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fzz7m.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fzz7m.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously detailed hydrological models are the only way to properly incorporate the varied topography and other unique factors in each situation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But it would seem useful for a lot of folks, whether tens of miles downsource of a mountain stream (such as might've been vital as the &lt;a href=&quot;http://www.denverpost.com/2016/08/01/40-years-after-big-thompson-flood/&quot; rel=&quot;noreferrer&quot;&gt;Big Thompson flood&lt;/a&gt; started), dozens of miles down a valley from a dammed waterway (like those further down the Feather/Sacramento Rivers tonight), or hundreds of miles down a flooding major river (such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Flood_of_1993&quot; rel=&quot;noreferrer&quot;&gt;the 1993 Mississippi Flood&lt;/a&gt;), especially given the varying warning networks in place around the world, to have a rough scale of how quickly an unexpected flood might translate downstream their way.  Is it a matter of hours, days, weeks?  A rough worst-case scenario of how quickly they may have to react is what is desired.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would seem a reasonable formula for a loose estimate might reasonably include the volume of water flowing, the expected channel size, and the elevation change (or alternatively, just the speed of the water... but if you knew that, you really don't need any special formula!).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does such a formula like this exist?&lt;br&gt;&#xA;Or are there good empirical estimates for those different situations I presented?&lt;br&gt;&#xA;Or is each case just so unique that there's no hope of such an estimate?&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-02-21T16:11:33.803" LastActivityDate="2017-08-18T00:55:14.900" Title="Is there a quick way to roughly estimate how quickly a flood will move downstream?" Tags="|hydrology|flooding|dams|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9685" PostTypeId="1" CreationDate="2017-02-13T20:04:53.267" Score="9" ViewCount="4533" Body="&lt;p&gt;Tectonic plates meeting (convergent plates) form mountains. But if those plates change direction (which I am just assuming they can over time, I have no idea if it's true) and start pulling apart (divergent plates), will the mountains automatically crumble away as the plates split, or can some mountains become part of one or the other plate, like clay sticking to your hands when you remove them?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Feel free to explain any prerequisite knowledge you feel I lack. This might be an important question to me.&lt;/p&gt;&#xA;" OwnerUserId="5870" LastEditorUserId="5870" LastEditDate="2017-02-13T23:02:50.397" LastActivityDate="2018-01-11T14:23:38.337" Title="Do divergent tectonic plates destroy mountains?" Tags="|plate-tectonics|mountains|tectonics|orogeny|" AnswerCount="4" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9686" PostTypeId="2" ParentId="9676" CreationDate="2017-02-13T20:33:17.187" Score="9" Body="&lt;p&gt;If it weren't for WW2 and the search for German submarines, the discovery of mid-ocean ridges might have waited until satellite based gravimetric mapping in the 1980s. It was the use of fine magnetometers (if I remember correctly) used to detect submarines that discovered the banding of magnetic stripes on the Atlantic ocean floor, followed by it's mirror image after a certain mid-point in the ocean basin. When superposed with bathymetric maps, it was further discovered that these magnetic stripes had their counterpoint in the same topographic region on the other side of a high point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The analysis of thousands of these ship transect records (released by the Navy following WW2)  led to the creation of partial ocean floor maps revealed very long parallel strips of rocks containing magnetic reversals reflected in mirror symmetry on the opposite of a mid-ocean rise. Ocean drilling then confirmed that only a spreading volcanic ridge, spewing magma over tens of millions of years could create such features. Following that, precise seismological mapping also confirmed this developing &quot;theory&quot; of plate tectonics, that laid to rest Alfred Wegener's model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These were heady times for the geologic community in the 60s and early 70s! All thanks to the Navy and WW2!&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-02-13T20:33:17.187" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9687" PostTypeId="2" ParentId="9676" CreationDate="2017-02-13T20:58:33.160" Score="4" Body="&lt;p&gt;I think the &lt;a href=&quot;https://pubs.usgs.gov/gip/dynamic/developing.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;U.S. Geological Survey&lt;/a&gt; has the gist of your answer -- prior to the mid-1900s, there wasn't enough seismological data to draw any conclusions:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;During the 20th century, improvements in seismic instrumentation and&#xA;  greater use of earthquake-recording instruments (seismographs)&#xA;  worldwide enabled scientists to learn that earthquakes tend to be&#xA;  concentrated in certain areas, most notably along the oceanic trenches&#xA;  and spreading ridges. By the late 1920s, seismologists were beginning&#xA;  to identify several prominent earthquake zones parallel to the&#xA;  trenches that typically were inclined 40-60° from the horizontal and&#xA;  extended several hundred kilometers into the Earth. These zones later&#xA;  became known as Wadati-Benioff zones, or simply Benioff zones, in&#xA;  honor of the seismologists who first recognized them, Kiyoo Wadati of&#xA;  Japan and Hugo Benioff of the United States. The study of global&#xA;  seismicity greatly advanced in the 1960s with the establishment of the&#xA;  Worldwide Standardized Seismograph Network (WWSSN) to monitor the&#xA;  compliance of the 1963 treaty banning above-ground testing of nuclear&#xA;  weapons. The much-improved data from the WWSSN instruments allowed&#xA;  seismologists to map precisely the zones of earthquake concentration&#xA;  worldwide.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This evidence led to &lt;a href=&quot;https://www.britannica.com/science/seafloor-spreading-hypothesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;geophysicist Harry H. Hess hypothesizing seafloor spreading in 1960&lt;/a&gt;. Researchers from Scripps Institution of Oceanography and Woods Hole Oceanographic Institute, among others, would spend years gathering evidence from the world's seafloors to test that theory, using oceanographic vessels, equipment, and analytical techniques that were not available in previous decades.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2017-02-13T20:58:33.160" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9688" PostTypeId="1" CreationDate="2017-02-14T00:47:04.590" Score="3" ViewCount="2227" Body="&lt;p&gt;I have a time series of moisture flux convergence. The values show positive and negative. What are these positive and negative values say? Can somebody help me how to interpret it? How it is related to precipitation? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whether positive values shows week precipitation and negative values shows strong precipitation?&lt;/p&gt;&#xA;" OwnerUserId="3194" LastActivityDate="2017-06-28T14:03:47.547" Title="How to interpret the values of moisture flux convergence?" Tags="|atmosphere|atmosphere-modelling|precipitation|moisture-flux|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9689" PostTypeId="2" ParentId="9685" CreationDate="2017-02-14T06:04:49.983" Score="6" Body="&lt;p&gt;Quite the opposite. Divergent boundaries can cause mountain (well, actually volcano) &lt;em&gt;building&lt;/em&gt;, because upwelling magma is part of the rifting process. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;First and most importantly, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mid-ocean_ridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mid-Ocean Ridge&lt;/a&gt; can be considered the longest, most massive mountain range in the world. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's more obvious, of course, &#xA; on continental rifts like the &lt;a href=&quot;https://en.wikipedia.org/wiki/East_African_Rift&quot; rel=&quot;nofollow noreferrer&quot;&gt;East African Rift&lt;/a&gt;. Mt. &lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Kilimanjaro&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kilimanjaro&lt;/a&gt;, a product of rift volcanism, is the highest mountain in Africa. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another famous locale of volcanism at a divergent boundary is &lt;a href=&quot;https://en.wikipedia.org/wiki/Iceland&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iceland&lt;/a&gt;, although a &lt;a href=&quot;https://en.wikipedia.org/wiki/Iceland_hotspot&quot; rel=&quot;nofollow noreferrer&quot;&gt;hot spot&lt;/a&gt; may play a role there. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aJwpy.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aJwpy.jpg&quot; alt=&quot;shows rift volcanism&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: USGS (via &lt;a href=&quot;http://aconcagua.geol.usu.edu/~arlowry/RGR/faq.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;usu.edu&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But BUT BUT it seems you want to know what happens to existing mountains. Some others have answered that only erosion destroys mountains, and that's mostly right, but only because it's a matter of timing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's often difficult for us humans to comprehend just how big geological time scales are. Most of the time, a mountain range created by a continental collision is eroded away completely by the time the next rift comes along. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This was the case along the eastern seaboard of the United States. The mountains created by the collosion of Africa and North America in the Carboniferous (the Alleghenian Orogeny) were almost completely gone by the Triassic, when the Atlantic Ocean began to form from a rift along about the same line. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, we have an example that might result in a qualified &quot;yes&quot; to your question, a little closer to the present. This is the way the Yellowstone Hotspot moved across what would become the northwestern United States.  One of the things that caused geologists to recognize the Yellowstone Caldera was the 80km gap it melted in a mountain range it passed under, separating the Gallatin Range in the north from the Red Range in the south. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The hotspot's track might just be the genesis of a new rift that breaks North America apart, given enough time and the right stresses. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2belM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2belM.jpg&quot; alt=&quot;![Yellowstone&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Source: &lt;a href=&quot;https://volcanoes.usgs.gov/volcanoes/yellowstone/yellowstone_geo_hist_52.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2017-02-19T04:04:25.947" LastActivityDate="2017-02-19T04:04:25.947" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="9690" PostTypeId="1" CreationDate="2017-02-14T06:37:08.573" Score="9" ViewCount="482" Body="&lt;p&gt;Cryolite is a mineral of aluminum (Na$_3$AlF$_6$). The only known natural deposit was found in &lt;a href=&quot;https://en.wikipedia.org/wiki/Ivittuut&quot; rel=&quot;noreferrer&quot;&gt;Ivittuut, Greenland&lt;/a&gt;. It was mined from 1854 to 1987 and yielded 3.7 Mt of Cryolite ore.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically my question is, &lt;strong&gt;why is this the only cryolite deposit known?&lt;/strong&gt; What is the origin of it and why didn't any more form?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are a lot of similar islands in the arctic: Canadian islands, Russian islands, Scandinavia and Svalbard, etc. Do geologists believe other Cryolite deposits are out there, just not discovered yet?&lt;/p&gt;&#xA;" OwnerUserId="2733" LastEditorUserId="1149" LastEditDate="2017-02-14T12:35:46.947" LastActivityDate="2017-02-17T05:19:31.293" Title="What is the geologic origin of Cryolite, and could there be more?" Tags="|geology|mineralogy|minerals|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9691" PostTypeId="2" ParentId="9690" CreationDate="2017-02-14T12:33:32.313" Score="9" Body="&lt;p&gt;&lt;a href=&quot;https://www.mindat.org/loc-1958.html&quot; rel=&quot;noreferrer&quot;&gt;Ivigtut Cryolite deposit, Ivittuut (Ivigtut), Arsuk Fjord, Sermersooq, Greenland&lt;/a&gt; deposit  is the first and largest occurrence of Cryolite but it is not the only location to report Cryolite.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some of these other locations listed below have produced collectible specimens but cryolite does not occur in large enough quantities to be mined. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other important locations are: &lt;a href=&quot;https://mrdata.usgs.gov/mrds/&quot; rel=&quot;noreferrer&quot;&gt;Reference&lt;/a&gt;&#xA;(I have seen specimens from these locations)&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;ST PETERS DOME PEGMATITE PROSPECT, Pikes Peak Colorado    &lt;/li&gt;&#xA;&lt;li&gt;Francon Quarry Mt St Hilaire, QUEBEC   &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;(other listed locations, &lt;a href=&quot;https://mrdata.usgs.gov/mrds/&quot; rel=&quot;noreferrer&quot;&gt;Reference&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;MONZONITE GROUP, Gunnison County Colorado&lt;/li&gt;&#xA;&lt;li&gt;FANNY GOUGE MINE, Yancey Co. North Carolina&lt;/li&gt;&#xA;&lt;li&gt;BARINGER HILL MINE, Llano, Texas&lt;/li&gt;&#xA;&lt;li&gt;MC GUIRE PIT Marathon Wisconsin.   &lt;/li&gt;&#xA;&lt;li&gt;Also reported from near Miass, Russia.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I also suspect there are other Canadian locations but Canada publishes less mineral data than the United States does. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cryolite occurs in &lt;a href=&quot;https://en.wikipedia.org/wiki/Syenite&quot; rel=&quot;noreferrer&quot;&gt;syenite&lt;/a&gt; vein deposits (igneous rock which is quartz deficient) which had abundant amounts of fluorine.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are 13 other known mineral specimens that contain primarily: Na, Al, F. &#xA;Cryolite is the most common mineral, due entirely to the Ivigtut deposit.&#xA;The geologic conditions at the Ivigtut deposit led to deposition of cryolite instead of an other mineral phase containing  Na, Al, and F.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I believe additional deposits with cryolite may be found in the future but the Greenland deposit is likely to remain the first and most important deposit.&#xA;There are a handful of completely unique ore deposits on earth, Ivigtut Cryolite deposit is one of them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See zincite from Franklin New Jersey as another example where a specific mineral was only ever commerically mined from a singular location.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="1242" LastEditDate="2017-02-17T05:19:31.293" LastActivityDate="2017-02-17T05:19:31.293" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9692" PostTypeId="2" ParentId="9685" CreationDate="2017-02-14T15:11:55.583" Score="4" Body="&lt;p&gt;Mountains tend to fault and collapse back to flatter ground once the building forces cease.  This is a very slow process and rarely leads to the complete elimination of a mountain range. So, left on their own, mountains tend to flatten, however, mountain ranges rarely completely disappear certainly not from these forces alone. Even the oldest mountain ranges tend to leave behind traces like hills and highlands. That is not to say they cannot be destroyed but it tends to require an extreme event like being trapped under an ice sheet or a second later mountain building event. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a continental crust slips over a divergent boundary, underplating occurs.  This is why most of the western USA is elevated. The forming east pacific plate is too new to sink back down so it gets welded to the bottom of the continental plate, pushing it upward. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This process can stop a spreading center. However, the underlying forces in the mantle remain, so a new spreading center may form somewhere else. The new spreading center is formed wherever the rock breaks more easily.  The thicker mountainous crust is generally harder to break than normal continental crust. So the spreading center tends not to form under mountains. A new spreading center that forms under a continental plate creates a rift valley which can become more mountainous than the surrounding crust, OR, it can end up thinner and more rugged, which depends on how fast the crust can move away from the upwelling. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2017-02-19T02:30:44.057" LastActivityDate="2017-02-19T02:30:44.057" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9693" PostTypeId="2" ParentId="9688" CreationDate="2017-02-14T16:23:07.610" Score="2" Body="&lt;p&gt;MFC can be employed to detect frontal structures and possible storms, which can be related with high values of MFC, which means convection of winds with high quantity of moisture...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a field map, you will be able to identify fronts as structures with high values of MFC. Try to plot along with pressure field for better understanding if you are able to.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Find more info here:&#xA;&lt;strong&gt;&lt;a href=&quot;http://www.spc.noaa.gov/publications/banacos/mfc-sls.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.spc.noaa.gov/publications/banacos/mfc-sls.pdf&lt;/a&gt;&lt;/strong&gt; &lt;/p&gt;&#xA;" OwnerUserId="7344" LastEditorUserId="7344" LastEditDate="2017-02-15T08:27:50.550" LastActivityDate="2017-02-15T08:27:50.550" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9694" PostTypeId="1" CreationDate="2017-02-14T20:06:16.577" Score="2" ViewCount="189" Body="&lt;p&gt;Some have studied the Lake Missoula glacial dam breaking West and having created the Coulees of Eastern Washington.  Who's studied the glacial dam breaking South and having cleared the Hudson River valley, forming the Verrazano Narrows, NY Harbor, Staten and Long Island, and washing through to the Atlantic Continental Shelf?&lt;/p&gt;&#xA;" OwnerUserId="7514" LastActivityDate="2017-02-14T21:10:19.177" Title="What current evidence is there for a Glacial Hudson River Valley deluge?" Tags="|geophysics|sea-level|regional-geology|dams|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9695" PostTypeId="2" ParentId="9694" CreationDate="2017-02-14T21:10:19.177" Score="1" Body="&lt;p&gt;&quot; Who's studied the glacial dam breaking South and having cleared the Hudson River valley, forming the Verrazano Narrows, NY Harbor, Staten and Long Island, and washing through to the Atlantic Continental Shelf?&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's a USGS group at Woods Hole that's done a bit of work on this back in 2004: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://darchive.mblwhoilibrary.org/bitstream/handle/1912/1630/Thieler%20et%20al.pdf?sequence=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;A catastrophic meltwater flood event and the formation of the&#xA;Hudson Shelf Valley&lt;/a&gt;   -From the paper: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;The ancestral Hudson River is generally thought to&#xA;have had a long history that began in the Late Cretaceous.&#xA;Uplift and tilting of the margin, resulting in&#xA;landward erosion and seaward growth, continued into&#xA;the Tertiary.&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;The Hudson River was repeatedly downcut into Cretaceous&#xA;coastal-plain strata during periods of Pleistocene marine&#xA;regression.&#xA;Scouring of the lower Hudson River during the last&#xA;glaciation formed a fiord in the region north of New York&#xA;City.&#xA;More recent fluvial downcutting was amplified by&#xA;drainage of late Wisconsinan glacial lakes, culminating in the failure of the terminal&#xA;moraine dam at the Narrows, which is a break in the&#xA;Harbor Hill moraine between Staten Island and&#xA;Long Island, New York. Borehole data across the&#xA;Narrows suggest that more than 100 m of Pleistocene&#xA;and Cretaceous sedimentary material was eroded as a&#xA;result of this breaching event. Uchupi et al. (2001) proposed that deposition&#xA;of sediment lobes on the continental shelf and erosion of the HSV were a consequence of&#xA;this catastrophic drainage.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might scour the references at the back of the paper and do some googling to find any more recent follow-up work they may have done. You could also try this guy at Woods Hole: Jeffrey P. Donnelly. He's first author on a paper titled: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://geology.gsapubs.org/content/33/2/89.abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;Catastrophic meltwater discharge down the Hudson Valley: A potential trigger for the Intra-Allerød cold period&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The paper is short on the drama of breached glacial dams, but long on how the sudden discharge of freshwater into an ocean alters circulation to cause a brief period of climate change. Fascinating stuff!&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-02-14T21:10:19.177" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9696" PostTypeId="1" CreationDate="2017-02-15T13:27:16.423" Score="2" ViewCount="6122" Body="&lt;p&gt;What are factors that cause rainfall while the sun is still shining. The phenomena is known as sunshower?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The information I found so far is very limited. Please help me answer this question if you know anything about it.&lt;/p&gt;&#xA;" OwnerUserId="7518" LastEditorUserId="5594" LastEditDate="2017-12-13T09:50:13.803" LastActivityDate="2018-07-24T20:26:02.013" Title="Why does it rain during the sunny day?" Tags="|sun|rain|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9697" PostTypeId="2" ParentId="9675" CreationDate="2017-02-15T15:20:28.423" Score="9" Body="&lt;p&gt;Samples don't need to be random to be valid, it helps but it is not essential especially if exhaustive, consistent, and has a large sample size, especially when dealing with observational studies. Representative sample is different than random sample. Remember we are not trying to attain the global temperature to the highest degree of accuracy in one instant, we are trying to measure the change in temperature over a long span of time. Thus consistency in location is more important than randomizing location.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fact that the sampling points do not move is essential, we know temperature is affected by regional conditions if the samples were re-randomized(moved) with every measurement it would make it less accurate not more. Remember what is being measured, the &lt;em&gt;change&lt;/em&gt;, because the sampling points are not moved the the change will be accurate because it essentially becomes a stratified sample. If I am measuring changes in engine temperature for instance I don not want to measure at a different point each time, as long as the points(locations) are consistent the sample will retain high accuracy. A random sampling would be LESS accurate because it would invite confounding because we know the distribution of temperature across the engine (or globe) is not random. Any shift in location between measurements would invite confounding data. Almost no science uses a truly random samples, it's just not possible. Consider things like exhaustive sampling, cluster sampling, stratified sampling, and systematic sampling all are used more often than true random sampling and each is more accurate than random in the right circumstances. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider an example, say you are trying to measure the temperature change in an engine over time. Where on the engine I attach my sensors does not matter as long as I do not move them, especially if I put many sensors on it. I could put thirty sensors all on the left side engine, and it would measure the change in temperature very accurately, compared to moving the sensors between every measurement. Don't fall for the perfect solution fallacy. Also remember this is an observational/descriptive study by its very nature.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each point on the map is more like a repetition, the real independent is the time at which they are sampled, which is either stratified or clustered depending on which study you refer too. Note that multiple sets of data points are also &lt;a href=&quot;http://www.pnas.org/content/105/36/13252.abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;compared&lt;/a&gt;. NOAA, BEST, etc. are each independent data sets that can be compared, and show the same &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/BAMS-88-9-1383&quot; rel=&quot;nofollow noreferrer&quot;&gt;pattern.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;High and low are used for measurements because that is all that was recorded in the oldest measurements, so changing the format would require throwing out all that data, drastically shortening the sample size (loosing more than half the time span). In this case the accuracy gained by the much larger number of samples is more than would be gained by a random or grid location. Random is rarely possible with historic data which is why the size and consistency of the data set is so important. The nice thing is these are also &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pubmed/23471405&quot; rel=&quot;nofollow noreferrer&quot;&gt;compared&lt;/a&gt; to other sampling methods on other time scales to test to see if they show the same &lt;a href=&quot;http://www.nature.com/nature/journal/v433/n7026/full/nature03265.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;pattern&lt;/a&gt;. Historic scientists are aware of the limitations of their data which is why independent verification is so important. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now consider &lt;a href=&quot;http://www.nature.com/nature/journal/v399/n6735/full/399429a0.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ice core data&lt;/a&gt;, I was surprised when you said surface temperature was the most used, I see ice core data far more often, because it records a much longer span of time, and records other things (like $CO_{2}$ content) as well. Again each core is a repetition and the core can be sampled in a random or stratified way, stratified is the most common because it is more exhaustive in a core sample. Ice cores are also compared to ice cores for m other locations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another consideration is cross-comparison, that is the use of multiple independent forms of measure, ice core compared to satellite, compared to surface, etc. Dozens of different forms of measurements/experiments are compared and show the same pattern. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.climatechange2013.org/images/report/WG1AR5_SPM_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;This&lt;/a&gt; is probably one of the best overviews of the science I have seen. It is a little old (2013) so if anyone has seen a more recent version I would love to use it instead.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="6465" LastEditDate="2017-07-14T08:01:19.837" LastActivityDate="2017-07-14T08:01:19.837" CommentCount="15" ContentLicense="CC BY-SA 3.0" />
  <row Id="9699" PostTypeId="1" CreationDate="2017-02-15T22:27:35.397" Score="2" ViewCount="47" Body="&lt;p&gt;Has anyone ever built and tested a topographical model of a 200 mile radius with a wind-farm in the middle to see how much wind speeds and wind direction change when the farm is active compared to before it was built? Obviously it takes power to turn the turbines in a wind generator, and that will slow the wind speed, but by how much? How much per turbine? Will it change the direction of the wind as compared to where the wind flowed BEFORE the farm was built? Sounds like a good and SCIENTIFIC question on the &quot;changing environment&quot; to me...&lt;/p&gt;&#xA;" OwnerUserId="7521" LastEditorUserId="7521" LastEditDate="2017-02-15T22:45:26.833" LastActivityDate="2017-02-15T22:45:26.833" Title="Topographical model of a wind-farm" Tags="|meteorology|atmosphere|climate-change|" AnswerCount="0" CommentCount="1" ClosedDate="2017-02-17T03:29:25.370" ContentLicense="CC BY-SA 3.0" />
  <row Id="9701" PostTypeId="1" AcceptedAnswerId="9702" CreationDate="2017-02-15T23:14:31.043" Score="9" ViewCount="5329" Body="&lt;p&gt;Let's imagine that a human (male or female) could be sent to the&#xA; past, anytime after the birth of our planet.  What would be their survival&#xA; probability over time?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this question is too hard to answer, I would also be interested in &lt;strong&gt;the first time (most distant) that a human could have survived their lifetime on Earth&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assume that this human is someone like &lt;a href=&quot;http://www.beargrylls.com/&quot;&gt;Bear Grylls&lt;/a&gt;, who is well trained to survive in nature.&lt;/p&gt;&#xA;" OwnerUserId="7522" LastEditorUserId="2470" LastEditDate="2017-02-16T06:47:36.427" LastActivityDate="2023-05-19T15:57:05.130" Title="For how long has the Earth been habitable for humans?" Tags="|earth-history|world-building|natural-conditions|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9702" PostTypeId="2" ParentId="9701" CreationDate="2017-02-16T03:22:51.253" Score="10" Body="&lt;p&gt;One needs breathable air, drinkable water, and food to survive. Food as we know it was nonexistent prior to the Ediacaran, which began about 635 million years ago. Life was exceedingly primitive (single celled) prior to that. Breathable air is a more significant challenge. A breathable atmosphere means sufficient oxygen and not too much carbon dioxide. Oxygen levels rose to above half it's current amount in the atmosphere about 850 million years ago, but carbon dioxide didn't fall below 5000 ppm until about 450 million years ago, when it dropped precipitously and caused an ice age and an extinction event. Extinction events would be something to avoid, so about 440 million years ago.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-02-16T03:22:51.253" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9704" PostTypeId="2" ParentId="9685" CreationDate="2017-02-16T15:58:22.683" Score="4" Body="&lt;p&gt;&lt;em&gt;Do divergent tectonic plates destroy mountains?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The short answer is &quot;&lt;strong&gt;no&lt;/strong&gt;&quot;. Erosion destroys mountains. Period. Not slumping, not faulting, not &quot;flowing back to flatness&quot; in the absence of compression, not sticking to a wayward plate. Just plain old, basic erosion. To fully understand the physics of rocks and the processes that lead to mountain building, you'd have to at least pick up a basic college level intro to geology. There are many good ones out there with awesome illustrations and clear explanations. On the other hand, simple videos can be useful too: You can check out these &lt;a href=&quot;https://www.geolsoc.org.uk/Plate-Tectonics/Chap3-Plate-Margins/Divergent&quot; rel=&quot;nofollow noreferrer&quot;&gt;short clips from the British Geological Society&lt;/a&gt; for a basic view of mountain building at plate margins.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer your question more precisely, the mountains that form at the edges of subduction zones are the result of several processes: 1) regional uplift of the overriding plate inland of the subduction boundary, 2) building of accretionary wedges from scraped materials off the subducting plate 3) Emplacement of island arc magmas as either extrusive (lavaflows) or intrusive (deep underground) plutons, and 4) Erosion, which cuts the deep channels through inherent structural weaknesses in this enormous mass of uplifted volcanic rock, exposing the sharp peaks and prominent ridges that we associate with mountains. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does reversing this subduction effectively stop these processes? Yes...sorta. And this has happened around the planet frequently enough over 4.5 billion years with the creation of at least to supercontinents, Gondwana and Pangea. I say &quot;sorta&quot; because the uplift is still there and the erosion continues unabated. Does reversing the subduction effectively reverse these processes in any way? No. Reversing the direction of India's movement into Tibet will not cause the Himalaya to slump back onto the sea floor. It's now chemically altered, bullet-hard, de-watered metamorphosed accretionary wedge. Only the steady grinding of glaciers and weather are going to &quot;destroy&quot; those mountains; the same process already occurring.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Will reversing South American subduction cause the Andes to &quot;stick&quot; to the Nazca plate as it's pulled back out from under South America, or slump back into the ocean? That would impose a strength to oceanic crust that it doesn't have. If anything, in this new &quot;extensional regime&quot;, oceanic crust would simply weaken, be uplifted by a shallow aesthenosphere, and likely be perforated by a mid-ocean ridge, or hotspots. Hope that helps!&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-02-16T15:58:22.683" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="9706" PostTypeId="1" AcceptedAnswerId="9708" CreationDate="2017-02-17T02:39:33.263" Score="4" ViewCount="1097" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Bauxite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bauxite&lt;/a&gt; is an mineral of Aluminum. Despite a general mineral wealth, the USA does not have any major Bauxite deposits, except for one in Arkansas. The mining town was named &lt;a href=&quot;https://en.wikipedia.org/wiki/Bauxite,_Arkansas&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bauxite, Arkansas&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mine operated from 1895 to 1981. It produced about 80 million metric tons of bauxite ore over its lifetime (just guestimating from &lt;a href=&quot;http://www.geology.ar.gov/pdf/pamphlets/Bauxite.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this pdf, page 6&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;So what is the origin of this deposit?&lt;/strong&gt; It seems strange to me, not being near any mountains. How did the minerals form? And why aren't there any others despite very similar terrain all over Arkansas and other states?&lt;/p&gt;&#xA;" OwnerUserId="2733" LastEditorUserId="2733" LastEditDate="2017-02-17T09:36:56.637" LastActivityDate="2023-09-01T12:08:47.387" Title="What is the geologic origin of the Bauxite deposit in Bauxite, Arkansas, and could there be more?" Tags="|geology|mineralogy|minerals|mining|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9707" PostTypeId="2" ParentId="2724" CreationDate="2017-02-17T03:22:22.153" Score="2" Body="&lt;p&gt;The speed of the lava flow from Kilauea depends on a few things:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The amount of activity at the source of lava.  This flow you are talking about is coming from a vent that is 20 miles from the Kilauea caldera.  So, it is more like a leak, than a true eruption.  There's not a lot of force behind these types of events and thus not a lot of lava coming out.&lt;/li&gt;&#xA;&lt;li&gt;The viscosity of the lava.  This is basalt, so it can move pretty quick, for lava.&lt;/li&gt;&#xA;&lt;li&gt;The terrain.  The source of the lava is not near the summit, but rather far down the mountain at only 700 ft elevation.   The surrounding terrain has a very shallow slope, which doesn't allow the lava to move downhill quickly.  &lt;/li&gt;&#xA;&lt;li&gt;The cooling rate of the lava.  It rains a lot in Pahoa.  Especially in late October.  This helps to cool and harden the lava, which slows the movement.&lt;/li&gt;&#xA;&lt;li&gt;Barriers and surface characteristics.  There are a lot of natural contours in the land, trees, and brush in the Pahoa area.  This helps to slow down the movement.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Having grown up on the Big Island, I can say from experience that these flows that come out of side vents are often slow enough to walk right up to and play with.  They don't move fast at all.  The reason it's such a big news event is because it nearly covered a main highway, which would've cut off a lot of people from the main town, Hilo.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fast-moving lava flows usually come from the main caldera, where the amount of lava erupting is far greater.  Also, Kilauea is really just a pimple on the side of Mauna Loa.  So, it is a bit of a release valve for the big volcano.  Shouldn't be too long before Mauna Loa erupts again and then you will see a lot of fast moving lava from a 13,000+ ft location. &lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-02-17T03:22:22.153" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9708" PostTypeId="2" ParentId="9706" CreationDate="2017-02-17T04:50:34.257" Score="7" Body="&lt;p&gt;The short answer is, bauxite requires a particular alumina-rich source rock and a specific set of conditions and processes to concentrate the aluminum in a specific order.&lt;/p&gt;&#xA;&lt;p&gt;From the &lt;a href=&quot;http://www.encyclopediaofarkansas.net/encyclopedia/entry-detail.aspx?entryID=2145&quot; rel=&quot;nofollow noreferrer&quot;&gt; Encyclopedia of Arkansas&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Arkansas bauxite region covers about 275 square miles in the northern part of the West Gulf Coastal Plain and is divided into two mining districts. One area is in Pulaski County, south and east of Little Rock, and the other is in nearby Saline County, northeast and east of Benton.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0ur10.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0ur10.jpg&quot; alt=&quot;Generalizrd geographic map of Arkansas&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(Source, &lt;a href=&quot;http://www.geology.ar.gov/education/teaching_kits.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Arkansas Geological Survey&lt;/a&gt;; a very detailed map can be downloaded &lt;a href=&quot;https://www.geology.arkansas.gov/docs/pdf/maps-and-data/geologic_maps/geologic-map-of-arkansas-1993-(34x52).pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;The source rock (&lt;a href=&quot;https://en.wikipedia.org/wiki/Nepheline_syenite&quot; rel=&quot;nofollow noreferrer&quot;&gt;nepheline syenite&lt;/a&gt;) for the bauxite appears as two isolated blue spots in the middle of the map above, surrounded by (orange) Tertiary sedimentary deposits. The town of Bauxite is just to the northwest of the southern spot.&lt;/p&gt;&#xA;&lt;p&gt;Rather than cut and paste EOA's description of the process, I decided on the following summary:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Magma was intruded during a Cretaceous volcanic event as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mississippi_embayment&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mississipi Rift&lt;/a&gt; opened, and this formed nepheline syenite, which has aluminum-rich &lt;a href=&quot;https://en.wikipedia.org/wiki/Nepheline&quot; rel=&quot;nofollow noreferrer&quot;&gt;nepheline&lt;/a&gt; where granite would have quartz.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The syenite decomposed, eroded, and was deposited as a soil on the edge of a shallow sea that filled the rift.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;In the Paleocene, tropical conditions caused the aluminum minerals toleach down into the soil, becoming concentrated into a hard layer called a &lt;a href=&quot;https://en.wikipedia.org/wiki/Laterite&quot; rel=&quot;nofollow noreferrer&quot;&gt;laterite&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;In the Eocene, some of the laterite was eroded and deposited as alluvial bauxite ore as the sea slowly filled in.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Both the original laterite and the alluvial deposits have been mined for aluminum.&lt;/p&gt;&#xA;&lt;p&gt;Your assertion that there are no other bauxite deposits in the US &lt;a href=&quot;https://en.wikipedia.org/wiki/Bauxite_mining_in_the_United_States&quot; rel=&quot;nofollow noreferrer&quot;&gt;is not true&lt;/a&gt;; other deposits formed in similar conditions in the southeastern US, and there is also &lt;a href=&quot;https://montana-aluminum.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;bauxite in Montana&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2023-09-01T12:08:47.387" LastActivityDate="2023-09-01T12:08:47.387" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="9709" PostTypeId="1" AcceptedAnswerId="9832" CreationDate="2017-02-17T10:44:30.590" Score="3" ViewCount="1377" Body="&lt;p&gt;I'm trying to validate some work I've been doing on extracting wind direction measurements from data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where can I access historical wind direction data online that gives ~hourly measurements? Specifically I'm looking for measurements in July 2014 off the south coast of France. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the time resolution is $&amp;lt;$hourly, that's better than nothing! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="7367" LastActivityDate="2017-03-06T20:40:25.817" Title="Wind direction data" Tags="|wind|open-data|" AnswerCount="2" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9710" PostTypeId="2" ParentId="9657" CreationDate="2017-02-17T11:47:02.710" Score="2" Body="&lt;p&gt;&lt;a href=&quot;http://www.dmi.dk/groenland/arkiver/vejrarkiv/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.dmi.dk/groenland/arkiver/vejrarkiv/&lt;/a&gt;&#xA;this is the info you are looking for i think it is in danish.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastActivityDate="2017-02-17T11:47:02.710" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9711" PostTypeId="1" AcceptedAnswerId="9719" CreationDate="2017-02-17T12:44:45.163" Score="6" ViewCount="258" Body="&lt;p&gt;As the title states, what maps, if any, do we have of convection currents inside the Earth's mantle, and which would you suggest to be the most detailed and accurate?&lt;/p&gt;&#xA;" OwnerUserId="5870" LastActivityDate="2017-02-17T18:16:01.307" Title="What are the best maps, if any, we have of the convection cells in the Earth's mantle?" Tags="|convection|mapping|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9712" PostTypeId="1" AcceptedAnswerId="9713" CreationDate="2017-02-17T13:03:06.613" Score="3" ViewCount="3227" Body="&lt;p&gt;In discussions from the National Weather Service, storm systems are often quantified in terms of DM, such as in &lt;a href=&quot;https://mesonet.agron.iastate.edu/wx/afos/p.php?pil=AFDLOX&amp;amp;e=201702151108&quot; rel=&quot;nofollow noreferrer&quot;&gt;this forecast discussion from Los Angeles/Oxnard on February 15, 2017&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A strong and large 487 DM low was located across the Gulf of Alaska.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;When the NWS uses &quot;dm&quot; is that short for &quot;dam&quot; as in decameters, or something else? And if so, why do they sometimes give these heights rather than the millibars?&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2017-02-17T14:13:47.723" Title="Why do meteorologists use DM and equal height surfaces for some maps?" Tags="|meteorology|barometric-pressure|radiosounding|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9713" PostTypeId="2" ParentId="9712" CreationDate="2017-02-17T13:03:06.613" Score="2" Body="&lt;p&gt;First, yes, DM does appear to be decameters (though Dm would be more proper).  D was actually the abbreviation I was taught for deca in grade school 20 years ago, but it appears da has become the &lt;a href=&quot;https://www.nist.gov/pml/weights-and-measures/prefixes&quot; rel=&quot;nofollow noreferrer&quot;&gt;official standard prefix&lt;/a&gt; now, perhaps because it was confused with deci (d).  They also list the spelling deka instead of deca as well, perhaps for similar reasons (though that may well still vary by locale?)&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Now, actually &lt;em&gt;all&lt;/em&gt; typical plots aloft are the varying height values where a given pressure is found (&lt;a href=&quot;http://weather.rap.ucar.edu/upper/upaCNTR_850.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;850 mb&lt;/a&gt;, &lt;a href=&quot;http://weather.rap.ucar.edu/upper/upaCNTR_500.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;500 mb&lt;/a&gt;, &lt;a href=&quot;http://weather.rap.ucar.edu/upper/upaCNTR_200.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;200 mb&lt;/a&gt;, etc).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why do we look at height variations on set pressure levels?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, for background, it's important to realize that, by and large, pressure and height are proportional, such that either one can determine a strong approximation of the other.  For large-scale weather you can directly invert them using forms of the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Hydrostatic_equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;hydrostatic equation&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\dfrac{\partial p}{\partial z} = -\rho g$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically this proves extremely accurate when vertical acceleration is small, which is generally anywhere outside of intense thunderstorms.  Even when it is less perfect, it's a pretty useful approximation for pressure variations important on the scale of synoptic weather.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Actually, the basic weather pressure map we're used to RELIES upon this relationship... typical storm pressures we hear are 900-1000 mb, and maps often look like:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/tyNRv.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tyNRv.gif&quot; alt=&quot;Surface analysis&quot;&gt;&lt;/a&gt;&#xA;But you'll find that pressure at the ground is lower in most locations than is indicated on such a map.  This is because, despite being called &quot;surface maps&quot;, they're actually sea-level pressure maps.  At any station situated above sea-level a weather balloon cannot acquire that sea-level pressure.  So the pressure must be extrapolated downward using these same equations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But that still doesn't answer why we'd opt for &lt;a href=&quot;http://www.theweatherprediction.com/basic/isopleths/&quot; rel=&quot;nofollow noreferrer&quot;&gt;isohypses&lt;/a&gt;...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One benefit may be that height maps are similar to topographic maps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But it well truly stem from early meteorological rules of thumb.  One important forecasting tool before advanced weather models came from the &lt;a href=&quot;http://en.wikipedia.org/wiki/Hypsometric_equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;thickness equation&lt;/a&gt; (an application of the hydrostatic approximation).  It works out that the thickness between 500 mb and 1000 mb was a helpful indication of what kind of precipitation would fall.  Values lower than 5400 m indicate that the air column is probably cold enough for snow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems quite feasible that this was relationship was noticed even before the equations were understood.  1000 mb is very close to the surface pressure in many of the big cities during the early development of meteorology (such as New York City, Boston, London, and Paris).  So all they'd need to notice is a connection of the 500 mb height and the precipitation type.  This might be easier than spotting a pattern of ratios of 5400 m pressure values to surface pressure values around 0.5.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the end, it probably goes back to how early upper-air observations were recorded.  It may well have been some guy going up in the balloons until radio, so would they have recorded at equal heights or equal pressures?  Or when radio and the early instrumentation were developed, what would draw them to choose set pressures or set heights?  I don't know the history well enough to give a certain answer to that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the modern era, models quite often use pressure coordinates (or similar &lt;a href=&quot;https://en.wikipedia.org/wiki/Sigma_coordinate_system&quot; rel=&quot;nofollow noreferrer&quot;&gt;sigma coordinates&lt;/a&gt;).  In addition, if you wished to calculate the &lt;a href=&quot;http://www.atmos.millersville.edu/~lead/OMEGA/QG_Omega_Home.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;quasigeostrophic omega equation&lt;/a&gt; or apply the &lt;a href=&quot;http://derecho.math.uwm.edu/classes/SynII/QGHgtTend.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;quasigeostrophic height tendency equation&lt;/a&gt;, perhaps equal pressure maps might be slightly more useful.  However, I tend to doubt either of these are nearly significant in the overall development of the practice. &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Also, why dekameters specifically?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good contour interval at 500 mb proves to be 60 meters.  With the precision of that final digit being so trivial, and with international communication being precious, they opted to just transmit the first three values.  So 5400 meters just became 540, so dekameters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, on the other hand, at 850 mb the reasonable contour was just 30 meters. (I believe for a long time, they opted to only send the last three digits of the height [as values are typically around 1200-1600 meters, the leading 1 is superfluous].  You can see reporting like this still on the University of Wyoming's &lt;a href=&quot;http://weather.uwyo.edu/upperair/uamap.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;website&lt;/a&gt;).  At a 30 meter interval, that final digit is twice just a little more helpful to place contours.  So meters were once used for 850 mb or 925 mb versus dekameters for 500 mb.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But, this has additional implications.... The reason these 850 mb heights fluctuate less than the 500 mb heights is because air density decreases with height.  The same mass of air takes up more room at higher heights.  So pressure changes more slowly as you rise:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/B8lcw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/B8lcw.png&quot; alt=&quot;P with height&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But not only does this lead to different scales being important on different pressure levels... it could well answer that question of why they chose to record at equally spaced pressures instead of heights in early ballooning.  Otherwise, they'd end up recording a ton of extra upper-level values which proved rather without value.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;hr&gt;&#xA;And why 500 mb values?  The 500 mb map is a very central pressure level (near the level of &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Level_of_nondivergence&quot; rel=&quot;nofollow noreferrer&quot;&gt;non-divergence&lt;/a&gt;).  Low-level maps like 850 mb will have lows more connected in shape/position to surface lows than lows aloft [850 is often looked at more for thermal and moisture setup].  Upper-level maps like 200 and 300 mb won't have closed lows [and are looked at a lot for wind structure, in addition to short and long-wave trough positions]. So a central level like 500 mb proves to be a very good level to look at upper-level low strength.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-02-17T14:13:47.723" LastActivityDate="2017-02-17T14:13:47.723" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9714" PostTypeId="2" ParentId="8488" CreationDate="2017-02-17T15:04:09.077" Score="3" Body="&lt;p&gt;Consider: If they evacuate the left-over waste product into space, as the station is NOT in geosynchronous orbit, the waste will eventually come back to Earth. Obviously, before then, the actual water content will be dissipated because of the vacuum of space (like freeze drying), but it will still have the opportunity to be re-absorbed as the molecules are drawn into Earth's atmosphere. &lt;/p&gt;&#xA;" OwnerUserId="7521" LastActivityDate="2017-02-17T15:04:09.077" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9715" PostTypeId="2" ParentId="9709" CreationDate="2017-02-17T16:08:49.840" Score="3" Body="&lt;p&gt;You can download the data from the CRU-NCEP database &lt;a href=&quot;https://crudata.uea.ac.uk/cru/data/hrg/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://crudata.uea.ac.uk/cru/data/hrg/&lt;/a&gt; &#xA;CRU stand for Climate Research Unit and it has the most accurate historical data available to the public. They are reanalyzed data from meteorological stations and ships. The highest resolution available is 0.5 latitude * 0.5 longitude degree grid. And for temporal resolution they have 6-hourly and daily. The data is in NetCDF format which is a format most map processing data use. If you don't know how to handle ncdf you could use Google Earth as well &lt;a href=&quot;https://crudata.uea.ac.uk/cru/data/hrg/cru_ts_3.23/ge/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://crudata.uea.ac.uk/cru/data/hrg/cru_ts_3.23/ge/&lt;/a&gt;  . &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To know more how the data is derived you can read this paper. Hope it helps. &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/joc.3711/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://onlinelibrary.wiley.com/doi/10.1002/joc.3711/abstract&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="7482" LastActivityDate="2017-02-17T16:08:49.840" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9716" PostTypeId="2" ParentId="9696" CreationDate="2017-02-17T16:12:27.373" Score="3" Body="&lt;p&gt;I think Wikipedia explains quite well. It is the wind that transport the airborne water droplets from a nearby showering cloud. It is quite common in UK especially near the coast which is often very windy. Usually the weather forecast will say that it has scattered shower with sunny spell.&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Sunshower&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Sunshower&lt;/a&gt;  &lt;/p&gt;&#xA;" OwnerUserId="7482" LastActivityDate="2017-02-17T16:12:27.373" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9717" PostTypeId="2" ParentId="9657" CreationDate="2017-02-17T16:14:42.983" Score="1" Body="&lt;p&gt;You can download the data from the CRU-NCEP database &lt;a href=&quot;https://crudata.uea.ac.uk/cru/data/hrg/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://crudata.uea.ac.uk/cru/data/hrg/&lt;/a&gt; CRU stand for Climate Research Unit and it has the most accurate historical data available to the public. They are reanalyzed data from meteorological stations and ships. The highest resolution available is 0.5 latitude * 0.5 longitude degree grid. And for temporal resolution they have 6-hourly and daily. The data is in NetCDF format which is a format most map processing data use. If you don't know how to handle ncdf you could use Google Earth as well &lt;a href=&quot;https://crudata.uea.ac.uk/cru/data/hrg/cru_ts_3.23/ge/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://crudata.uea.ac.uk/cru/data/hrg/cru_ts_3.23/ge/&lt;/a&gt; .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To know more how the data is derived you can read this paper. Hope it helps. &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/joc.3711/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://onlinelibrary.wiley.com/doi/10.1002/joc.3711/abstract&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7482" LastActivityDate="2017-02-17T16:14:42.983" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9718" PostTypeId="1" AcceptedAnswerId="9723" CreationDate="2017-02-17T17:53:57.840" Score="10" ViewCount="344" Body="&lt;p&gt;I was reading &lt;a href=&quot;http://www.bbc.com/news/world-asia-39000936&quot; rel=&quot;noreferrer&quot;&gt;this article&lt;/a&gt; about Zealandia and got excited that there could be an underwater continent.  However, when viewing the image (below) it appears that Zealandia is much smaller than any other continent.   The article says the bases considered were:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;elevation above the surrounding area &lt;/li&gt;&#xA;&lt;li&gt;distinctive geology &lt;/li&gt;&#xA;&lt;li&gt;a well-defined area &lt;/li&gt;&#xA;&lt;li&gt;a crust thicker than the regular ocean floor&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Is there some criteria on size that should be met to be classified as a continent? If so, does Zealandia meet that criteria?  Or,  is it possible that Zealandia is a continental fragment?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QMOzP.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QMOzP.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2017-02-17T21:12:10.513" LastActivityDate="2017-02-18T06:46:42.333" Title="Is Zealandia really big enough to be called a continent?" Tags="|geology|continent|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9719" PostTypeId="2" ParentId="9711" CreationDate="2017-02-17T18:16:01.307" Score="6" Body="&lt;p&gt;If you're looking for a cool, well detailed map of convection cells that looks like a modern weather map....forget it. What you're looking for has been notoriously difficult to produce, if not impossible. Even the most advanced seismic tomography techniques using seismic wavespeeds can only resolve mantle &quot;features&quot; thousands of kilometers in scale, but really, only in the X-Y plane. These techniques do a poor job of resolving anything in the Z plane.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even the locations of convection cell boundaries appears harder to find than theory suggests. Currently, the influence of convection boundaries has been mapped from the surface elevations of oceanic plates, but those maps look like odd &quot;heat maps&quot; indicating where oceanic crust has domed up beneath upward mantle flow. No vertical flow lines boundaries are even remotely suggested with these two-dimensional maps. You can read the actual paper published in Nature, 2016 here: &lt;a href=&quot;http://www.nature.com/articles/ngeo2709.epdf?referrer_access_token=xyfElxE_isdL5EMVpGTCYNRgN0jAjWel9jnR3ZoTv0P4lC1R2QEP3HfrlHKZBuxA8F_fuJlt1tG3kKT2I4g-wk_Nl7SbyUzQvqAS0rmbwukqahum_LIIMc-7mNFLZJRfRt9EtY2RT1_ovRyqI1UTTkQY_d2Z6omuCuGohKmhPvxRdXpKaeX-i462HDClarPMfhJgoJvS5qIMXOXhZYauUuyeTfXFGsVhY2sm4CGOCznhvdFLxUdN7fO-2IboddBVfpkUjxb6MkTD7gYFybqp1XeOGwc6MQ1rHhGPkrixHj4_JeZ_HHXbrMtITOQHpOlb&amp;amp;tracking_referrer=www.iflscience.com&quot; rel=&quot;noreferrer&quot;&gt;Global dynamic topography observations reveal limited influence of large-scale mantle flow&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-02-17T18:16:01.307" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9720" PostTypeId="1" AcceptedAnswerId="9721" CreationDate="2017-02-17T21:16:36.150" Score="2" ViewCount="4550" Body="&lt;p&gt;Here are two questions I had ever since I first heard about plate-tectonics.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;How can the plates move? Before you suggest me some page to read about plate movement mechanics, let me clarify that I am not asking about the mechanics behind plate movement here. But I am talking about the physical possibility of plate movement.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;When we look at the map of plates, all of them are tightly packed, with not an inch of space or gap to move. The complex shape of surrounding plates, blocks all freedom of movement. Then how can the theory say that plates can move?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you can't follow my explanation, consider a jigsaw puzzle in which the blocks are correctly set up. Can we move a block from the middle now? We can not because the blocks are tightly interlocked, and because of their complex shape. The same is the situation here too, in fact much more complex! Each plates is tightly surrounded by complex shaped other plates, making any movement in any direction impossible!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See the below given a map of tectonic plates for example. It is evident the plates are actually interlocked so tightly that, it is impossible to move in any direction, because of the presence of another plate in opposite direction. There is no freedom of movement available, in any direction! The complex shape of plates make movements impossible!  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vvVHW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vvVHW.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;My second question is this: It is said that, all continents were a single large continent millions of years ago. And then much later, continents 'drifted away', reaching current shape and locations.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;If tectonic plates does not even have hundreds of miles of gaps between them to move, how can continents drift away so far, even thousands of miles away?  Certainly plates can't move this far, because the whole earth surface is divided into plates, with no space left for plates to move thousands of miles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So how did the continents drift away this far? Or do we have to assume that continents are simply floating over the tectonic plates?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the plate tectonics theory a complete hoax?&lt;/p&gt;&#xA;" OwnerUserId="7534" LastEditorUserId="15071" LastEditorDisplayName="user1161" LastEditDate="2022-06-15T09:44:29.970" LastActivityDate="2022-06-15T09:44:29.970" Title="How do tightly packed plates move in the theory of plate tectonics?" Tags="|geology|plate-tectonics|" AnswerCount="4" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="9721" PostTypeId="2" ParentId="9720" CreationDate="2017-02-18T02:37:52.517" Score="12" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;isn't the plate tectonics theory a complete hoax?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No, it isn't. It's a perfectly valid theory that has much supporting evidence from all disciples of earth sciences, and it explains features that would otherwise remain unexplained. It is so widely and universally accepted that questioning it (particularly in the way you are doing) is likely to elicit a very hostile response from the scientific community, similar to how people would react to questioning Newton's laws of gravity.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How can the plates move? (before you suggest me some page to read about plate movement mechanics, let me clarify that i am not asking about the mechanics behind plate movement here. But i am talking about the physical possibility of plate movement)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Since you are not asking about the mechanics I will spare you from explanation about mantle convection and similar processes.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;all of them are tightly packed, with not an inch of space or gap to move...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You are entirely correct. They don't have any gap to move. This is why we have mountain ranges where continental plates collide (or converge):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/prJJs.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/prJJs.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In places where an oceanic plate converges, plates can go underneath one the other in a process called subduction. This causes melting around the subducting plate, causing the formation of volcanic arcs:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lluvy.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lluvy.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where plates pull apart and diverge you can have impressive rift valleys:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qqvuc.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qqvuc.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or submarine trenches:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xOPsN.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xOPsN.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And of course, let's not forget about the earthquakes that occur when all of these things form. While you may doubt it, it is very real to the people affected by such natural disasters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Everything I just mentioned happens &lt;em&gt;because&lt;/em&gt; the plates are so tight and have nowhere to move. Just because you think a theory is incorrect because it doesn't fit your extremely simplistic way of how things should work, does &lt;em&gt;not&lt;/em&gt; mean it is in fact incorrect. Nature does its thing regardless of what you, me, and everyone else thinks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;(Photographs either public domain or mine)&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2017-02-18T02:54:41.653" LastActivityDate="2017-02-18T02:54:41.653" CommentCount="15" ContentLicense="CC BY-SA 3.0" />
  <row Id="9722" PostTypeId="2" ParentId="9685" CreationDate="2017-02-18T02:53:48.797" Score="5" Body="&lt;p&gt;I want to add some nice examples of how divergent plate movement can actually create mountains, not destroy them. Here are two photographs I took several years ago from the Red Sea rift near Eilat, Israel:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Gd1iB.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Gd1iB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/q9TuZ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/q9TuZ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7BwcW.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7BwcW.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These mountains exist because of the plate movement. Divergent plate boundaries cause rifting, and the geomorphological expression of a rift is a valley. Valleys are, by definition, surrounded by mountains. The mountains that you see in the photographs could not have been there if there hasn't been a divergent boundary.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-02-18T02:53:48.797" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9723" PostTypeId="2" ParentId="9718" CreationDate="2017-02-18T04:43:00.390" Score="6" Body="&lt;p&gt;In the &lt;a href=&quot;http://www.geosociety.org/gsatoday/archive/27/3/article/GSATG321A.1.htm&quot; rel=&quot;noreferrer&quot;&gt;GSA Today article&lt;/a&gt; that Michael linked to in the comments, it says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Glossary of Geology defines a continent as “one of the Earth’s major land masses, including both dry land and continental shelves” (Neuendorf et al., 2005). It is generally agreed that continents have all the following attributes: &lt;/p&gt;&#xA;  &#xA;  &lt;ol&gt;&#xA;  &lt;li&gt;high elevation relative to regions floored by oceanic crust; &lt;/li&gt;&#xA;  &lt;li&gt;a broad range of siliceous igneous, metamorphic, and sedimentary rocks; &lt;/li&gt;&#xA;  &lt;li&gt;thicker crust and lower seismic velocity structure than oceanic crustal regions; and &lt;/li&gt;&#xA;  &lt;li&gt;&lt;strong&gt;well-defined limits around a large enough area to be considered a continent rather than a microcontinent or continental fragment.&lt;/strong&gt; &lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;  &#xA;  &lt;p&gt;The first three points are defining elements of continental crust and are explained in many geoscience textbooks and reviews (e.g., Holmes, 1965; Christensen and Mooney, 1995; Levander et al., 2005; Kearey et al., 2009; Condie, 2015). &lt;strong&gt;To our knowledge, the last point—how “major” a piece of continental crust has to be to be called a continent—is almost never discussed, Cogley (1984) being an exception&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and goes on to mention:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Further­more, the 4.9 Mkm^2 area of continental crust is large and separate enough to be considered not just as a continental fragment or a microcontinent, but as an actual continent—Zealandia. This is not a sudden discovery but a gradual realization; as recently as 10 years ago we would not have had the accumulated data or confidence in interpretation to write this paper. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This part is important too:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;spatial and tectonic separation, along with intervening oceanic crust, means that the Zealandia continental crust is physically separate from that of Australia. If the Cato Trough did not exist, then the content of this paper would be describing the scientific advance that the Australian continent was 4.9 Mkm2 larger than previously thought.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So to wrap it up, they say:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Being &gt;1 Mkm^2 in area, and bounded by well-defined geologic and geographic limits, Zealandia is, by our definition, large enough to be termed a continent. At 4.9 Mkm^2, &lt;strong&gt;Zealandia is substantially bigger than any features termed microcontinents and continental fragments, ~12× the area of Mauritia and ~6× the area of Madagascar&lt;/strong&gt;. It is also substantially larger than the area of the largest intraoceanic large igneous province, the Ontong Java Plateau (1.9 Mkm^2).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2017-02-18T06:46:42.333" LastActivityDate="2017-02-18T06:46:42.333" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9724" PostTypeId="2" ParentId="9720" CreationDate="2017-02-18T17:27:12.317" Score="12" Body="&lt;p&gt;tectonic plates are not completely rigid they can bend, flex, and in the case of oceanic plate, get pushed under each other and melted back down.&lt;strong&gt;The plates move by sliding under each other, melting, or bending&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take a toffee-bar candy, hang most of it off the side of a table and put something heavy on the other end to hold it in place, wait a few hours, just under its own weight it will bend 90 degrees. However bend it fast by only a few degrees and it will snap. Rock behaves in a similar fashion, do it slowly enough and with enough force and you can bend it. Basically all solids behave like this to a certain extent. tectonic plates are not rigid on the large scale.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;bending rock leaves behind traces like &lt;a href=&quot;https://naturalishistoria.files.wordpress.com/2014/07/loughshinny_folds-rock-bent-wikipedia1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; and this&lt;a href=&quot;https://i.stack.imgur.com/fXreW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fXreW.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;bend it to fast and the rock breaks creating a fault lines like &lt;a href=&quot;http://epod.usra.edu/.a/6a0105371bb32c970b01bb0957e2a8970d-pi&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; and this&lt;a href=&quot;https://i.stack.imgur.com/dpuS7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dpuS7.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;plates pushed down get remelted, it helps if you think of oceanic crust as exposed mantle that has been cooled into a solid, while continental crust is much less dense and sort of floats on top of the more liquid mantle. that's why continental crust does not subduct but oceanic does. In essence there are huge gaps between the the permanent plate material, it just cools when exposed forming a hard surface skin called an oceanic plate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hazyh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hazyh.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;we can even see that in how earth quakes behave around subduction zones getting deeper and deeper in the direction of movement until the stop indicating where there are no solids left to break. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://blogs.agu.org/mountainbeltway/files/2011/03/hist1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; is an earthquake depth map for japan. notice how they get deeper in the direction of the movement of the pacific plate (west by NW) as it dives under japan. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you look at a global map of plate movement you will notice that at then end of a moving plate (in the direction of movement) is either a mountain range or a subduction zone, or often both. &lt;a href=&quot;https://i.stack.imgur.com/0zuPS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0zuPS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2018-04-22T04:04:47.683" LastActivityDate="2018-04-22T04:04:47.683" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9727" PostTypeId="2" ParentId="9720" CreationDate="2017-02-18T23:38:29.240" Score="4" Body="&lt;p&gt;At continental scales, plates don't really behave like solid objects. Furthermore, their edges can't compete with the forces below in the mantle, that move them around willy nilly over the earth' surface. Your mental &quot;block&quot; is that you think of plates as solid, like concrete, or sheets of ice floating on water. They are not!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It may be more useful to think of a tectonic plate as a large sheet of semi-solid caramel floating around on a thick sludge of gooey hot chocolate. To a tiny, microscopic bug, the caramel plate might feel solid but to an omnipotent being with a wooden spoon, the plate is weak and bendy. &lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-02-18T23:38:29.240" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9728" PostTypeId="1" AcceptedAnswerId="9730" CreationDate="2017-02-18T23:39:37.477" Score="7" ViewCount="17823" Body="&lt;p&gt;I know that if the sun stopped shining, Earth would lose it's heat and we'd all freeze and die. On the other hand, we don't keep increasing temperature when the sun shines because heat escapes to space. But how does the heat leave earth's atmosphere if space is a vacuum and vacuums don't conduct heat except through waves?&lt;/p&gt;&#xA;" OwnerUserId="7539" LastActivityDate="2019-05-11T16:54:58.743" Title="How does Earth's heat escape to space?" Tags="|atmosphere|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9729" PostTypeId="2" ParentId="9728" CreationDate="2017-02-19T00:14:50.207" Score="2" Body="&lt;p&gt;Through radiation, which doesn't require matter to transfer heat. Here is a good explanation: &lt;a href=&quot;http://coolcosmos.ipac.caltech.edu/cosmic_classroom/light_lessons/thermal/transfer.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;How Does Heat Travel?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5077" LastEditorUserId="6093" LastEditDate="2017-02-19T21:36:27.880" LastActivityDate="2017-02-19T21:36:27.880" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9730" PostTypeId="2" ParentId="9728" CreationDate="2017-02-19T02:28:49.887" Score="8" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;How does Earth's heat escape to space?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;TL;DR: By the exact same method heat from the Sun escapes into space. Electromagnetic radiation does not require a medium. In fact, electromagnetic radiation works best in a vacuum; no medium is required. Intervening matter has an annoying tendency to absorb electromagnetic radiation. That absorption, in a nutshell, is the greenhouse gas effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;Earth's heat escapes into space via a complex set of processes. One is convection. Eagles, hawks, and other birds use those rising thermals to get a free ride to altitude. A second mechanism is latent heat. Evaporation of water is an endothermic process, meaning it absorbs energy from the surroundings (this is why sweating keeps you cool). Condensation is an exothermic process. While falling rain cools the surface, the net transfer is upward.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Those rising columns of warm air can only go so high; they only rarely cross the tropopause (the boundary between the troposphere and stratosphere), and that is only in the case extremely unstable of conditions. Latent heat, along with birds, ride those rising columns of air. This brings up a third and the ultimate mechanism by which the Earth's heat escapes into space, which is electromagnetic radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Every object, including the Earth's surface, absorbs and radiates heat electromagnetically. The atmosphere does the same. The atmosphere absorbs most of the electromagnetic radiation emitted by the Earth's surface. (I qualified that with &quot;most&quot; because there is a small window in the thermal infrared that goes directly into space, at least when there aren't clouds.) This absorbed radiation is quickly re-emitted as thermal radiation, but in a random direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The heat carried upward by thermals, by latent heat, and by surface radiation eventually does make its way into space as electromagnetic radiation. &lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-02-19T02:28:49.887" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="9731" PostTypeId="2" ParentId="9657" CreationDate="2017-02-19T13:46:06.377" Score="0" Body="&lt;p&gt;There is a buoy station &lt;a href=&quot;http://www.ndbc.noaa.gov/station_page.php?station=TFBLK&quot; rel=&quot;nofollow noreferrer&quot;&gt;Station TFBLK - 10.0 nm WNW on Blakknes, Iceland&lt;/a&gt; but it seems to me it only logs data related to waves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tha U.S. National Data Buoy Center web site has a &quot;radial search&quot; tool where you put as input the lat/lon of your point of interest and a distance and it gives you a list of observations (I think made by ships). For example &lt;a href=&quot;http://www.ndbc.noaa.gov/radial_search.php?lat1=65.698N&amp;amp;lon1=24.778W&amp;amp;uom=M&amp;amp;dist=450&amp;amp;ot=A&amp;amp;time=12&quot; rel=&quot;nofollow noreferrer&quot;&gt;this is the search centered at the TFBLK buoy with a query radius of 450km.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, the Environmental Working Group Arctic Meteorology and Climate Atlas:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Temporal Coverage: 1950-01-01 to 1995-12-31 &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Parameter: Air Temperature, Cloud Amount/Frequency, Humidity, Incoming Solar&#xA;  Radiation, Longwave Radiation, Net Radiation, Precipitation Amount, Sea Level&#xA;  Pressure, Snow, Snow Depth, Snow Water Equivalent, Solar Radiation, Surface Air&#xA;  Temperature, Wind Speed&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Summary&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The Environmental Working Group (EWG) was established in June 1995&#xA;  under the framework of the U.S.-Russian Joint Commission on Economic&#xA;  and Technological Cooperation. In January 1996, the EWG Arctic&#xA;  Climatology Group took on the task of compiling digital data on arctic&#xA;  regions to expand scientific understanding of the Arctic. This work&#xA;  resulted in a set of three atlases on CD-ROM for arctic oceanography,&#xA;  sea ice, and meteorology. The Arctic Meteorology and Climate Atlas was&#xA;  developed by specialists from the Arctic and Antarctic Research&#xA;  Institute (AARI), St. Petersburg, Russia, the University of&#xA;  Washington, Seattle, and the National Snow and Ice Data Center,&#xA;  University of Colorado, Boulder. The Atlas contains three main&#xA;  sections: a history section, a 'Primer,' and a data section. The&#xA;  history section and Primer provide background and introductory&#xA;  information for newcomers to arctic meteorology, while the data&#xA;  section contains gridded fields of meteorological parameters, and&#xA;  newly released meteorological station data from Russian and other&#xA;  sources. In addition, the Atlas includes several English translations&#xA;  of Russian technical documents, and a glossary of meteorological terms&#xA;  in English and Russian. Users can download the CD-ROM from the NSIDC&#xA;  FTP site. NSIDC also distributes the EWG Joint .S.-Russian Atlas of&#xA;  the Arctic Ocean (Winter and Summer periods), and the EWG Joint&#xA;  U.S.-Russian Arctic Sea Ice Atlas.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Environmental Working Group. Edited by F. Fetterer and V. F. Radionov. 2000. &lt;em&gt;Environmental Working Group Arctic Meteorology and Climate Atlas, Version 1&lt;/em&gt;. Data Set ID: G01938. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: &lt;a href=&quot;http://dx.doi.org/10.7265/N5MS3QNJ&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://dx.doi.org/10.7265/N5MS3QNJ&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, the data from drifting buoys:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rigor, I. G. Compiled by Polar Science Center. 2002. &lt;em&gt;IABP Drifting Buoy Pressure, Temperature, Position, and Interpolated Ice Velocity, Version 1&lt;/em&gt;. Boulder, Colorado USA. NSIDC: National Snow and Ice Data Center. doi: &lt;a href=&quot;http://dx.doi.org/10.7265/N53X84K7&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://dx.doi.org/10.7265/N53X84K7&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;you can see some data here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://iabp.apl.washington.edu/raw_plots.php?bid=300234063738740&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://iabp.apl.washington.edu/raw_plots.php?bid=300234063738740&lt;/a&gt;&#xA;&lt;a href=&quot;http://iabp.apl.washington.edu/raw_plots.php?bid=300234062556750&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://iabp.apl.washington.edu/raw_plots.php?bid=300234062556750&lt;/a&gt;&#xA;&lt;a href=&quot;http://iabp.apl.washington.edu/raw_plots.php?bid=83723#top&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://iabp.apl.washington.edu/raw_plots.php?bid=83723#top&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7545" LastEditorUserId="7545" LastEditDate="2017-02-26T19:23:38.420" LastActivityDate="2017-02-26T19:23:38.420" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9732" PostTypeId="1" CreationDate="2017-02-19T19:00:09.910" Score="3" ViewCount="18719" Body="&lt;p&gt;Here in Perú , we call those rocks:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Shale = &lt;em&gt;Lutita&lt;/em&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Siltstone = &lt;em&gt;Limonita&lt;/em&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;But as far as I know we don't use the terms claystone and mudstone in Spanish terms.&lt;/p&gt;&#xA;" OwnerUserId="7538" LastEditorUserId="2470" LastEditDate="2021-11-09T17:29:55.420" LastActivityDate="2021-11-11T11:33:37.283" Title="What's the diference between claystone, silt, mud, mudstone, mudrock, clay, shale and siltstone?" Tags="|geology|petrology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="9733" PostTypeId="2" ParentId="9732" CreationDate="2017-02-19T19:21:01.613" Score="8" Body="&lt;p&gt;Clastic sedimentary rocks are classified by size of the sediment particles making up the rock.  Particle size descriptions like sand, silt, and clay have specific meaning in geology and engineering. (see chart below).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shales, mudstones and claystones are rock types that are very similar to each other.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Siltstone - greater than half of the composition is silt-sized&#xA;particles. &lt;/li&gt;&#xA;&lt;li&gt;Claystone - greater than half of the composition is&#xA;clay-sized particles. &lt;/li&gt;&#xA;&lt;li&gt;Mudstone - hardened mud; a mix of silt and clay&#xA;sized particles.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The difference between mudstone and shale is that mudstones break into blocky pieces whereas shales break into thin chips with roughly parallel tops and bottoms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The terms shale and claystone are sometimes used interchangeably. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&#xA;&lt;a href=&quot;http://www.pitt.edu/~cejones/GeoImages/5SedimentaryRocks/ClasticSedRocks/MudstonesShales1.html&quot; rel=&quot;noreferrer&quot;&gt;Mudstones and shales&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.pinterest.com/stevendknighton/sedimentary-rock/&quot; rel=&quot;noreferrer&quot;&gt;Fun rock charts on pinterest&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mUWVU.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mUWVU.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-02-19T19:21:01.613" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9736" PostTypeId="1" CreationDate="2017-02-20T07:15:42.720" Score="6" ViewCount="175" Body="&lt;p&gt;I did a quick search, but couldn't pull any statistics from it.  On tornado risk days, many I interact with in Oklahoma become concerned or panicked that they don't have a shelter.  I am guessing the percentage of people with shelters is actually pretty low, and in such situations a statistic like that might be encouraging to folks.  Does anybody know where I can find such statistics?&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="543" LastEditDate="2017-02-20T07:39:47.200" LastActivityDate="2017-04-21T17:12:20.380" Title="How many buildings in tornado prone-areas have storm shelters?" Tags="|tornado|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9737" PostTypeId="1" CreationDate="2017-02-20T09:42:34.353" Score="1" ViewCount="81" Body="&lt;p&gt;I am looking at basics academic papers which tell about the physical floods mechanisms. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In particular something that says that: 'lower temperatures reduce evapotranspiration, enhancing wet soil conditions which reduce the soil infiltration promoting water runoff and eventually fluvial peak flows'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do you know anything about this?&lt;/p&gt;&#xA;" OwnerUserId="6978" LastEditorUserId="6" LastEditDate="2017-02-20T11:04:21.393" LastActivityDate="2017-02-21T23:53:43.900" Title="Soil moisture conditions and air temperatures - literature needed" Tags="|temperature|flooding|soil-moisture|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9738" PostTypeId="1" AcceptedAnswerId="9739" CreationDate="2017-02-20T10:25:22.610" Score="5" ViewCount="62717" Body="&lt;p&gt;I am making a quiz and I want to know whether Australia or Oceania is the continent? I have searched it on Google but I can't find an answer.&lt;/p&gt;&#xA;" OwnerUserId="7549" LastActivityDate="2022-08-03T09:17:30.400" Title="Is the continent with Australia in it Oceania or Australia?" Tags="|continent|" AnswerCount="5" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9739" PostTypeId="2" ParentId="9738" CreationDate="2017-02-20T11:48:34.763" Score="4" Body="&lt;p&gt;Australia is a continent and Oceania is a region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Continent#Definitions_and_application&quot; rel=&quot;nofollow noreferrer&quot;&gt;Continents&lt;/a&gt; are vaguely defined as large landmasses separated by water or just by historical context. Earth scientists have much more precise definitions of what a continental plate is vs an oceanic plate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case of Australia, the continental plate consists of the landmasses Australia, Tasmania and New Guinea. Sometimes other names are used to clarify the difference between the country Australia and the continent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Oceania#Definitions&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oceania&lt;/a&gt; is the region of island nations and sometimes Australia, located in or near the Pacific Ocean. There are a number of different definitions depending on the context. Usually Oceania includes islands that have no affiliation with the Australian continent. &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;A personal comment inspired by aretxabaleta's different, but also correct answer: &#xA;Exact definitions can be difficult and often misleading as we tend to use language to label objects rather than processes, whiles Earth is better understood as processes, scientifically and socially. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-02-20T23:20:24.130" LastActivityDate="2017-02-20T23:20:24.130" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9740" PostTypeId="2" ParentId="9738" CreationDate="2017-02-20T13:45:35.663" Score="5" Body="&lt;p&gt;Partly, it depends on where you got educated. In many countries of Europe, Oceania is the continent. Calling the continent Australia is pretty much considered &quot;English-centric&quot;. The reasoning for calling it Oceania is that Australia is only part of the continent. The extend of the mainland during the ice ages included part of today's Indonesia and Papua-New Guinea. While calling it Australia makes some sense and it is the largest part of the continent, in a sense it is like if we were to call Asia, Russia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AoBCn.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AoBCn.png&quot; alt=&quot;De Maximilian Dörrbecker (Chumwa) - Self made, using this map for the background, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=7382691&quot;&gt;&lt;/a&gt;&#xA;Source: Wikipedia (Maximilian Dörrbecker (Chumwa) - Self made, using this map for the background, CC BY-SA 3.0, &lt;a href=&quot;https://commons.wikimedia.org/w/index.php?curid=7382691&quot; rel=&quot;noreferrer&quot;&gt;https://commons.wikimedia.org/w/index.php?curid=7382691&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2017-02-20T13:45:35.663" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9741" PostTypeId="2" ParentId="9736" CreationDate="2017-02-20T16:04:57.363" Score="1" Body="&lt;p&gt;Have you perhaps contact the National Weather Service or FEMA about that ? If not, then maybe find out from real estate that they might have data for each houses in your state. They may have the data or not, but it is hard to know. All I know is that each state has different types of soils that can or can't built storm shelter. I heard in Texas almost 1/2 of the buildings there do not have a storm shelter, because the soil in Texas are not strong enough to withstand against the flooding. That kind of thing ...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do not know if you have seen this, &lt;a href=&quot;https://stateimpact.npr.org/oklahoma/2013/09/27/mapped-which-oklahoma-schools-have-storm-shelters/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://stateimpact.npr.org/oklahoma/2013/09/27/mapped-which-oklahoma-schools-have-storm-shelters/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.esri.com/news/arcuser/0104/storm.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.esri.com/news/arcuser/0104/storm.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another one is the reason why an individual passed away from flooding in a storm shelter&#xA;&lt;a href=&quot;http://mashable.com/2015/05/07/oklahoma-city-storm-fatality/#KGEHNAxU5sqq&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://mashable.com/2015/05/07/oklahoma-city-storm-fatality/#KGEHNAxU5sqq&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5771" LastActivityDate="2017-02-20T16:04:57.363" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9744" PostTypeId="2" ParentId="9737" CreationDate="2017-02-21T02:20:10.183" Score="2" Body="&lt;p&gt;If you're after &quot;basic&quot; academic work, I suggest the following 2003 textbook from the Utah State University entitled, &quot;Rainfall Runoff Processes&quot;, chapter 2:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://hydrology.usu.edu/RRP/userdata/4/87/ch2.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Runoff Generation Mechanisms&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It looks like a pretty good compendium of what you're looking for with easy-to-understand text and clear diagrams. Further detail, if needed, can be found by hunting down the references within. The entire textbook can be downloaded here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://hydrology.usu.edu/RRP/userdata/4/87/RainfallRunoffProcesses.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rainfall Runoff Processes&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-02-21T02:20:10.183" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9745" PostTypeId="1" CreationDate="2017-02-21T02:45:56.233" Score="22" ViewCount="5430" Body="&lt;p&gt;Mount Everest is 8,848 metres (29,028 feet) above sea level and is the result of a continental plate smashing into another continental plate. Can a tectonic process build a mountain that's even higher? (Volcanoes excluded!)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MCnWk.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MCnWk.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7333" LastEditorUserId="1149" LastEditDate="2017-04-04T14:02:05.643" LastActivityDate="2021-03-08T10:36:13.267" Title="How high can a mountain possibly get?" Tags="|geology|tectonics|mountain-building|isostasy|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9746" PostTypeId="1" CreationDate="2017-02-21T10:27:02.120" Score="8" ViewCount="494" Body="&lt;p&gt;The 21-Feb-2016 BBC new article &lt;a href=&quot;http://www.bbc.com/news/world-asia-39036138&quot; rel=&quot;nofollow noreferrer&quot;&gt;Singapore 'fire rainbow' cloud phenomenon lights up sky&lt;/a&gt; shows several photos of a rainbow-like iridescence in clouds on a sunny day in Singapore (about 1.3 degrees North latitude). Local time was about 17:10, 2 hours before sunset.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've read about circumhorizontal arcs &lt;a href=&quot;http://www.amusingplanet.com/2013/05/fire-rainbows-rare-cloud-phenomenon.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;in this article&lt;/a&gt;, but the photos there (and other places) show a definite orientation - approximately parallel to the horizon with red on top (higher elevation angle). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However the photos from Singapore show tight circular patterns that resemble a color-coded contour map around a hill. So I think the explanation for these would not be identical to the explanation for a classic circumhorizontal arc or &quot;Fire Rainbow&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;below x2:&lt;/strong&gt; Photo of the phenomenon seen in Singapore, from  &lt;a href=&quot;http://www.bbc.com/news/world-asia-39036138&quot; rel=&quot;nofollow noreferrer&quot;&gt;Singapore 'fire rainbow' cloud phenomenon lights up sky&lt;/a&gt;. Photo credit: Zhou Guang Ping.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4KXIO.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4KXIO.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4SPzi.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4SPzi.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; example of a circumhorizontal arc from &lt;a href=&quot;http://www.amusingplanet.com/2013/05/fire-rainbows-rare-cloud-phenomenon.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fire Rainbows: A Rare Cloud Phenomenon&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ElxAh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ElxAh.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2019-08-18T15:20:19.530" LastActivityDate="2022-08-10T13:52:24.707" Title="What mechanism leads to these spectacular iridescent patterns in clouds labeled as a &quot;Fire Rainbow&quot;?" Tags="|clouds|atmospheric-optics|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="9748" PostTypeId="1" CreationDate="2017-02-21T16:22:12.933" Score="5" ViewCount="408" Body="&lt;p&gt;Ocean plates subduct beneath continental plates. Does this make the oceanic plates stretch and become thinner so that the elevation of the sea flow is lower? Is this why oceans form where they do - when water collects in these low areas?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="1242" LastEditDate="2017-02-22T05:10:17.017" LastActivityDate="2017-03-10T05:47:10.377" Title="Does subduction of plates make them stretch and form the oceans?" Tags="|geology|oceanography|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9749" PostTypeId="2" ParentId="9748" CreationDate="2017-02-21T20:42:20.847" Score="-3" Body="&lt;p&gt;No.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The oceanic crust is basically the same material as the upper mantle, but its cooled under lower pressure into a solid. Continental crust is much less dense felsic material that tends to stay on top of oceanic crust. There isn't enough continental crust to cover the planet so the rest gets filled in with cooled mantle products (oceanic crust). As the plate moves, it creates a divergent boundary (e.g. the mid-Atlantic ridge) through which mantle material is forced out and cools into basalt. The oceanic crust is not stretched thin.  Instead it is originally thin when it forms at the divergent boundary because it is only cooled crust of a more ductile semi-molten solid. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oceanic crust is made of three layers: a layer of sediment on top and two layers of mantle sourced rock.  The layers of mantle sourced rock differ structurally because they cooled at different rates.  So, there is fast cooled basalt on top of ultramafic slow cooled material. This bottom most layer also gets thicker as the plate gets older since more material cools, causing that portion of the plate to sink further down. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for why there is the extreme difference in height, think of oceanic crust as the crust on cooled soup while continental crust is more like styrofoam sitting on top.  The styrofoam sticks up higher because it is much lighter and thicker, and rock under high pressure and heat behaves enough like a liquid for buoyancy to matter.  Oceans form over the lower oceanic crust because water runs downhill. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="543" LastEditDate="2017-03-10T05:47:10.377" LastActivityDate="2017-03-10T05:47:10.377" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="9750" PostTypeId="2" ParentId="9737" CreationDate="2017-02-21T23:53:43.900" Score="0" Body="&lt;p&gt;This is generally true, but like most things in nature, there are exceptions. There is no capacity to hold additional water once soils are saturated to the surface and infiltration is limited by the generally slow rate of groundwater flow. This produces saturation-dependent overland flow and greatly increases runoff.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another effect is that cold conditions reduce vegetation growth, especially annual grasses. The lower groundcover promotes runoff.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, under dry conditions some soil types can become hydrophobic, which also reduces infiltration and increases runoff. &lt;a href=&quot;http://soilquality.org.au/factsheets/water-repellency&quot; rel=&quot;nofollow noreferrer&quot;&gt;This can be due to coating of soil particles with organic substances&lt;/a&gt; as can occur in native forests in Australia due to eucalyptus and other oils. I believe this is a bit of an over-simplification because it does not consider the unsaturated flow dynamics that could impede infiltration without organic coatings.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-02-21T23:53:43.900" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9751" PostTypeId="1" CreationDate="2017-02-22T02:52:08.740" Score="4" ViewCount="2115" Body="&lt;p&gt;I've read that cloud-to-ground lightning can create &lt;a href=&quot;https://en.wikipedia.org/wiki/Fulgurite&quot; rel=&quot;noreferrer&quot;&gt;fulgurites&lt;/a&gt;.  Does ground-to-cloud lightning also create crystals within the earth as it surges  through the minerals?&lt;/p&gt;&#xA;" OwnerUserId="7559" LastEditorUserId="2470" LastEditDate="2017-02-22T12:00:27.363" LastActivityDate="2019-08-04T06:36:59.263" Title="Does ground-to-cloud lightning create crystals as well?" Tags="|meteorology|geochemistry|mineralogy|petrology|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9752" PostTypeId="1" CreationDate="2017-02-22T04:47:28.527" Score="4" ViewCount="908" Body="&lt;p&gt;I would like to know how to calculate how much water fell on California during, for instance, the mid-February 2017 flood.  I know how to look up the total rainfall at a specific weather station.  And, given a meteorological model output, I could calculate the total water precipitated over some area.  However, I don't know of any standard method (using observations) to calculate total cumulative water fallen over some area.  I've seen multi-station precipitation indexes like the one shown below.  But, I don't know how to use that to calculate total water that has fallen to the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Based on observations, how can we calculate the total cumulative water volume (or mass) that has fallen on a large area during a storm?  And, using that method, can we calculate how much water fell on California during the 2017 February flooding events?  The only thing I can think of is to use the rainfall measurements at every station, interpolate across the area of interest, and then integrate.  Though, that seems like quite an intensive GIS project.  Is there a better,standardized way to make the calculation?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/H3QPU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/H3QPU.png&quot; alt=&quot;https://cdec.water.ca.gov/cgi-progs/products/PLOT_FSI.pdf&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="6298" LastEditDate="2018-05-22T05:57:15.473" LastActivityDate="2018-05-22T05:57:15.473" Title="How can we calculate the total water mass that falls during a flood?" Tags="|meteorology|rainfall|" AnswerCount="4" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9754" PostTypeId="2" ParentId="9752" CreationDate="2017-02-22T10:36:21.790" Score="2" Body="&lt;p&gt;I don't have the answer for you, but I can point you to the tools that can be used to get such an answer.  The &lt;a href=&quot;http://water.weather.gov/precip/download.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Advanced Hydrologic Prediction Service&lt;/a&gt; compiles rainfall grids using radar, surface observations, and a variety of other sources.  Options offered include daily, month-to-date, and archived data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can probably quite reasonably put the Shapefile download option into a GIS application, such as &lt;a href=&quot;http://www.esri.com/software/arcgis/explorer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Grass GIS&lt;/a&gt; or &lt;a href=&quot;https://www.arcgis.com/features/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ArcGIS&lt;/a&gt;, then limit it to the state (or area of interest) and compute an average or total.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alternative, you can download it as NetCDF, which I know you'd be able to open in &lt;a href=&quot;http://cola.gmu.edu/grads/&quot; rel=&quot;nofollow noreferrer&quot;&gt;GrADS&lt;/a&gt;/&lt;a href=&quot;http://opengrads.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;OpenGrADS&lt;/a&gt;, mask it to a certain area using some sort of shape file or geometry, and then run an areal average on it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I really do wish more straightforward, user-adaptable data were easily available (and no guarantee it's not, I just don't know a source).  But at least this will give you the tools to figure out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And while you're focused on rainfall, perhaps read up on central California's &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Flood_of_1862&quot; rel=&quot;nofollow noreferrer&quot;&gt;Great Flood of 1852&lt;/a&gt;!&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;One other way to get an estimate of the total volume of water would be to use stream flow values combined with reservoir level changes, and attempt to estimate what percentage of rainfall escapes the reservoir system.  But at that point you're getting a very rough estimate, because the monitoring system doesn't measure every small stream emptying into the sea... and a significant (and varying) percentage of the water infiltrates the soil or evaporates.  Those complications could be incorporated into the calculation, but in the end, that seems a complicated way to solve a problem we already have more complete information on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You asked for how much water that is.  Well, we can just as easily get a fair estimate from the map:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1BtLB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1BtLB.png&quot; alt=&quot;Feb precip&quot;&gt;&lt;/a&gt;&#xA;(month to date as of February 22nd)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If that's an average of 8&quot; over the state of California, that's:&lt;br&gt;&#xA;$ \pu{8 in} \times \pu{163,696 mi}^2 =$ &lt;strong&gt;&lt;a href=&quot;https://www.wolframalpha.com/input/?i=8%22%20x%20163,696%20sqmi%20in%20gallons&quot; rel=&quot;nofollow noreferrer&quot;&gt;23 trillion gallons&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even if we're off by a factor of as much as 2 on the estimates, such that it's only 4&quot; average, or alternatively 16&quot; average, that just changes it to 11.5 trillion gallons and 46 trillion gallons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which begs the point... we don't often think in terms of trillions of gallons.  Trillions of gallons seems a ton, but even just a meager 0.35&quot; over the state would equate to a trillion gallons.  Perhaps normalizing it to the area... such that it'd be $ \pu{140000 gal/mi^2}$... is a little better.  But still, a typical person would struggle to recognize whether any given value in this form would result in a flood or a droughts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's why we often just work in terms of percentiles, or graphs, or return periods, or just give the average in terms of inches itself.  It may not click great with everyone, but for many, such units are just a little more interpretable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(And in case you wondered, a gallon of water weighs about &lt;a href=&quot;https://www.wolframalpha.com/input/?i=1%20gal%20of%20water%20in%20pounds&quot; rel=&quot;nofollow noreferrer&quot;&gt;8.36 pounds&lt;/a&gt;, so that's about &lt;strong&gt;100 trillion pounds&lt;/strong&gt; of water, again sounding like a lot, but to most people, so does 1 trillion pounds of water from a little 0.10&quot; inch rain system)&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-02-24T04:33:28.720" LastActivityDate="2017-02-24T04:33:28.720" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9755" PostTypeId="2" ParentId="9746" CreationDate="2017-02-22T12:08:42.743" Score="2" Body="&lt;p&gt;this looks like mother of pearl clouds &lt;a href=&quot;https://en.wikipedia.org/wiki/Polar_stratospheric_cloud&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Polar_stratospheric_cloud&lt;/a&gt;&#xA;they are made of ice crystals very high in the atmosphere the only clouds higher in the atmosphere are noctilucent clouds.if you google mother of pearl clouds there is a lot of pictures and information.&#xA;as a result of global warming the stratosphere is getting colder this makes&#xA;mother of pearl clouds or rainbow clouds visible from larger areas of our planet then before(more info is needed to dokument this statement of mine).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An other alternative is irradecent clouds,They have many of the same properties as mother of pearl clouds &lt;a href=&quot;https://en.wikipedia.org/wiki/Cloud_iridescence&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Cloud_iridescence&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The last alternative is a pollen rainbow but they do often form in the direction of the sun or moon(it is a little hard to see if the sun is behind the clouds in your pictures)The colors of a pollen rainbow is often more vibrant than other types of optical phnomena &lt;a href=&quot;https://soranews24.com/2019/03/09/high-pollen-levels-in-eastern-japan-create-pretty-rainbow-suns/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://soranews24.com/2019/03/09/high-pollen-levels-in-eastern-japan-create-pretty-rainbow-suns/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6258" LastEditDate="2019-08-18T16:20:32.630" LastActivityDate="2019-08-18T16:20:32.630" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="9757" PostTypeId="1" AcceptedAnswerId="9766" CreationDate="2017-02-22T15:50:55.230" Score="2" ViewCount="145" Body="&lt;p&gt;Does anyone know the &quot;life-cycle&quot; of the averages used for daily and yearly temperatures and rainfall by the National Weather Service?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have lived in the same (semi-desert) area for over 40 yrs, and have seen the yearly rainfall average go from 13 inches per year to 24 inches per year and back down to 18 inches per year over that period of time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, I failed to pay attention to the specific &quot;whens&quot; of this phenomenon...  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Simple math tells me that this is NOT possible if we are using total data - only possible if we use an interval. But, I cannot find any reference to such an interval ... .  Same things I have been seen with average temperatures ... .&lt;/p&gt;&#xA;" OwnerUserId="7521" LastEditorUserId="5594" LastEditDate="2017-12-13T09:46:46.027" LastActivityDate="2017-12-13T09:46:46.027" Title="National Weather Service &quot;average daily/yearly&quot; (temp, rainfall) life cycle?" Tags="|climate|temperature|climate-models|rainfall|rain|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9758" PostTypeId="2" ParentId="9745" CreationDate="2017-02-22T19:51:51.310" Score="17" Body="&lt;p&gt;Found an article that used a simple analytical modelling to determine how high a mountain can be. &lt;a href=&quot;https://talkingphysics.wordpress.com/2011/09/08/how-high-can-mountains-be/&quot; rel=&quot;noreferrer&quot;&gt;Reference&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Based on simple physics, tallest a mountain will be on Earth is ~10 km.&#xA;This is based on:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Simple cone shape for the mountain. Vol ≈ &lt;span class=&quot;math-container&quot;&gt;$r^2 h$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;Based on weight of the mountain:  Weight W ≈ &lt;span class=&quot;math-container&quot;&gt;$\rho g r^2 h$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Stress σ the mountain exerts on the ground underneath it is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;σ ≈ Weight/Area ≈ &lt;span class=&quot;math-container&quot;&gt;$(\rho g r^2 h)/r^2$&lt;/span&gt; ≈ &lt;span class=&quot;math-container&quot;&gt;$\rho g h$&lt;/span&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;The limiting factor is the compressive strength of the rock:&#xA;Assume granite with an average density &lt;span class=&quot;math-container&quot;&gt;$ρ$&lt;/span&gt; = 3 g/cm&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt;.&#xA;Compressive strength is &lt;span class=&quot;math-container&quot;&gt;$\sigma_C$&lt;/span&gt; = 200 MPa = &lt;span class=&quot;math-container&quot;&gt;$2 \times 10^8\, N/m^2$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;Stress = Compressive strength of rock  σ = &lt;span class=&quot;math-container&quot;&gt;$\sigma_C$&lt;/span&gt; or &lt;span class=&quot;math-container&quot;&gt;$\rho g h_{max} = \sigma_C$&lt;/span&gt;.&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Calculate max height:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$h_{max}$&lt;/span&gt; ≈ &lt;span class=&quot;math-container&quot;&gt;$\sigma_C/(\rho g)$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$h_{max}$&lt;/span&gt; ≈ &lt;span class=&quot;math-container&quot;&gt;$\frac{2 \times 10^8\, N/m^2}{3 \times 10^3 kg/m^3 \times 10\, m/s^2)}$&lt;/span&gt;≈ &lt;span class=&quot;math-container&quot;&gt;$10^4\, m$&lt;/span&gt; = 10 km        &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="18081" LastEditDate="2020-06-17T07:09:57.337" LastActivityDate="2020-06-17T07:09:57.337" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="9759" PostTypeId="1" AcceptedAnswerId="9761" CreationDate="2017-02-22T21:06:16.403" Score="8" ViewCount="968" Body="&lt;p&gt;I know that helium is a very light and rare gas on Earth because Earths gravity is not strong enough to keep it. Instead, helium and hydrogen are rising through the atmosphere and escape into outer space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: How massive would Earth have to be so that it could keep helium in the atmosphere? 2, 5, or 10 times the actual mass? Could we, for example, compare it to Neptune or Saturn?&lt;/p&gt;&#xA;" OwnerUserId="7031" LastEditorUserId="5594" LastEditDate="2017-12-13T09:42:51.453" LastActivityDate="2017-12-13T09:42:51.453" Title="What &quot;g&quot; would be needed to keep helium on Earth?" Tags="|geophysics|geochemistry|planetary-science|atmospheric-chemistry|gas|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9760" PostTypeId="1" CreationDate="2017-02-22T21:16:03.827" Score="7" ViewCount="691" Body="&lt;p&gt;I was seeing Madagascar on Google Maps and accidentally i saw a circle shape near Bebao. Coordinates are &lt;a href=&quot;https://www.google.com/maps/@-17.4317443,44.644248,33509m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;17.4317443°E and 44.644248°S&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please, to satisfy my curiosity, can you tell me why is this shape like a circle? &lt;/p&gt;&#xA;" OwnerUserId="7565" LastEditorUserId="5594" LastEditDate="2017-12-13T09:44:32.930" LastActivityDate="2017-12-13T09:44:32.930" Title="A circle shape in Madagascar" Tags="|geology|volcanology|earth-history|geomorphology|mapping|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9761" PostTypeId="2" ParentId="9759" CreationDate="2017-02-23T00:35:51.733" Score="8" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_escape&quot; rel=&quot;noreferrer&quot;&gt;Atmospheric escape&lt;/a&gt; is the loss of planetary atmospheric gases to outer space. You'd never be able to contain ALL of any gas forever by gravity. Ultimately you end up in the rarefied atmosphere where there is some probability that a molecule of gas will reach escape velocity. The probability distribution is given by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Maxwell%E2%80%93Boltzmann_distribution&quot; rel=&quot;noreferrer&quot;&gt;Maxwell-Boltzmann distribution&lt;/a&gt; and the thermal escape mechanism is known as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_escape#Thermal_escape_mechanisms&quot; rel=&quot;noreferrer&quot;&gt;Jeans escape&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On earth the problem is compounded by the fact that helium is lighter that the other gases. So (1) helium migrates to the upper atmosphere because of its density and (2) helium atoms on average have the same kinetic energy as oxygen and nitrogen molecules which means that helium atoms are on average traveling much faster than oxygen or nitrogen molecules. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;All of this is made more complicated by needing a temperature profile of the atmosphere as a function of the height. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It doesn't help to assume temperature of background radiation because even at that temperature you can calculate the probability of a helium atom having 80% of light speed. This sort of like being able to calculate the probability of throwing $n$ heads in a row regardless of how big $n$ is.&lt;/p&gt;&#xA;" OwnerUserId="4685" LastEditorUserId="4685" LastEditDate="2017-02-23T22:27:19.213" LastActivityDate="2017-02-23T22:27:19.213" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9762" PostTypeId="1" CreationDate="2017-02-23T02:39:16.247" Score="3" ViewCount="8987" Body="&lt;p&gt;Crater is above a vent&#xA;whereas a vent is below it.&#xA;All the best....&lt;/p&gt;&#xA;" OwnerUserId="7538" LastEditorUserId="-1" LastEditDate="2017-10-02T15:25:02.443" LastActivityDate="2020-03-08T10:36:07.397" Title="What's the difference between a crater and a vent?" Tags="|geology|" AnswerCount="2" CommentCount="2" ClosedDate="2019-06-02T12:31:45.293" ContentLicense="CC BY-SA 3.0" />
  <row Id="9763" PostTypeId="2" ParentId="9760" CreationDate="2017-02-23T02:53:24.443" Score="8" Body="&lt;p&gt;It is an extinct volcanic crater.&#xA;The location is not listed as one of the &lt;a href=&quot;https://www.volcanodiscovery.com/madagascar.html&quot; rel=&quot;noreferrer&quot;&gt;active volcanoes in Madagascar&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Simplified geologic map of Madagascar (&lt;a href=&quot;https://databasin.org/maps/new#datasets=1a187e2f29e24e98b2c4d45c109d3bb3&quot; rel=&quot;noreferrer&quot;&gt;reference&lt;/a&gt;) shows the crater to be mapped as basaltic / Gabbro lava, &lt;a href=&quot;https://i.stack.imgur.com/DlAoZ.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DlAoZ.png&quot; alt=&quot;crater&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="111" LastEditDate="2017-02-23T14:47:24.903" LastActivityDate="2017-02-23T14:47:24.903" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9764" PostTypeId="1" CreationDate="2017-02-23T04:10:15.393" Score="8" ViewCount="1107" Body="&lt;p&gt;At what stage is the studies on effect of urbanization on weather events (eg: Rainfall, Temperature, UHI) are now? There has been a number of observational and modelling studies around the world and it has been found (In my understanding) that urbanization cause increase in frequency and intensity of heavy rainfall, higher temperature, heat island, changes in boundary layer etc. in urbanized region, mainly due to land-surface change. &#xA;Now, What challenges and possibilities are there in this particular research field?&lt;/p&gt;&#xA;" OwnerUserId="735" LastActivityDate="2017-07-31T17:14:58.697" Title="Effect of urbanization on weather events" Tags="|meteorology|atmosphere|models|numerical-modelling|urban-climate|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9765" PostTypeId="1" CreationDate="2017-02-23T04:55:07.310" Score="4" ViewCount="36" Body="&lt;p&gt;It's amazing how much water traveled down the slopes of California during the first two months of &lt;a href=&quot;http://sf.curbed.com/maps/california-floods-storm-damage-map&quot; rel=&quot;nofollow noreferrer&quot;&gt;rain/flooding of 2017&lt;/a&gt;.  Since the amount of water was far greater than anything in recent history, there were many landslides and widening of rivers.  As part of that process, there was a lot of sediment that traveled downstream.  Is there anyway to estimate how much sediment there was?  If so, how can we calculate it?&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-02-23T04:55:07.310" Title="How can we estimate the amount of sediment that traveled downstream during the California flood?" Tags="|sedimentology|flooding|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9766" PostTypeId="2" ParentId="9757" CreationDate="2017-02-23T05:45:50.983" Score="2" Body="&lt;p&gt;Climate normals are computed over 30 years.  Not sure why that number of years was chosen specifically.  Perhaps a recent incentive is to identify climate changes (though it actually would make warming appear less significant when looking at anomalies).  But, given that those trends have only gotten interest in the past few decades, the only historical reason I can fathom is to sooner allow more sites to be used.  30 years is a fair number of data points statistically, but for daily normals, it should still have a significant error range.  It would seem a 50 or mean year normals length might be more useful at this point, though indeed climate changing might be comparable to the confidence interval.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But regardless of why they chose that value, that should be the period they are reporting.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you wanted to verify these values, I was able to find pages to get the &lt;a href=&quot;ftp://ftp.atdd.noaa.gov/pub/GCOS/WMO-Normals/RA-IV/US/GROUP1/&quot; rel=&quot;nofollow noreferrer&quot;&gt;1961-1990 normals&lt;/a&gt; (use the find command within &lt;a href=&quot;ftp://ftp.atdd.noaa.gov/pub/GCOS/WMO-Normals/TABLES/REG_IV/FILE_ID4.TXT&quot; rel=&quot;nofollow noreferrer&quot;&gt;this file&lt;/a&gt; to determine station id), &lt;a href=&quot;https://www.ncdc.noaa.gov/cgi-bin/climatenormals/climatenormals.pl?directive=prod_select2&amp;amp;prodtype=CLIM81&amp;amp;subrnum=&quot; rel=&quot;nofollow noreferrer&quot;&gt;1971-2000 normals&lt;/a&gt;, and of course &lt;a href=&quot;https://www.ncdc.noaa.gov/cdo-web/datatools/normals&quot; rel=&quot;nofollow noreferrer&quot;&gt;1981-2000 normals&lt;/a&gt;.&lt;br&gt;&#xA;Or a more robust option would be to use NWS' great &lt;a href=&quot;http://sercc.com/nowdata.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ClimateNow data portal&lt;/a&gt; (select your local NWS office).  There you can look at annual data for the entire record length, search for specific values, or compute normals for any period you wish (select your station, then Monthly summarized data, and then the mean at the bottom is your normal over the time period you selected) (can also change to avg temp).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know these portals can be a bit complex to some, so if you wish to mention the area, I can pull the values and edit the answer.  And then you can see just how much the normals have changed :-)&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2017-02-23T05:45:50.983" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9767" PostTypeId="2" ParentId="9764" CreationDate="2017-02-23T06:12:07.213" Score="4" Body="&lt;p&gt;I did my undergraduate capstone on observational moisture changes around cities.  It's an interesting field, though it certainly seems fairly challenging to draw out and explain changes given the incredible spatial and temporal variability.  So that's definitely one of the challenges to it.  Another is the current observational density, as there are very few micronets setup and satellite resolution probably isn't helpful to diagnose variations on small time/distance scales.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But, while it definitely doesn't have near the attention (or money) that climate modeling itself does, there are a few sharp folks working in the field at least.  From my experience, having dabbled on the topic but having incomplete research familiarity particularly over the past decade, it would seem that theoretical microscale modelling might be the most fruitful research direction.  Computing power and models continue to step up, and there's much better room for experimentation.  But then, it'll still be very hard to demonstrate that those idealized simulations match reality, and impacts to connect changes definitively to theory/causes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Indeed, if somehow sharp links can be made that are powerfully convincing, then work could be directed into reshaping urban planning to address such changes.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2017-02-23T06:12:07.213" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9769" PostTypeId="1" AcceptedAnswerId="9770" CreationDate="2017-02-23T12:15:03.153" Score="7" ViewCount="260" Body="&lt;p&gt;I am reading &lt;a href=&quot;https://what-if.xkcd.com/42/&quot; rel=&quot;noreferrer&quot;&gt;Longest Sunset&lt;/a&gt; from XKCD. At first, I've thought that he mentions these phenomena just for fun, but it turns out to me that it might happens, based on the level of somewhat seriousness that I perceive from his writing. He doesn't talk about that in detail.&lt;/p&gt;&#xA;&lt;h1&gt;For the sunset:&lt;/h1&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LVLNb.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LVLNb.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Sunset starts the instant the Sun touches the horizon, and ends when it disappears completely. If the Sun touches the horizon and then lifts back up, &lt;strong&gt;the sunset is disqualified&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I'm not sure if &lt;em&gt;the sunset is disqualified&lt;/em&gt; is because it happens, but we don't count it, or because he's just making fun. But I can't prove that this cannot happen. The more we head to the poles, the shorter the night is. Ultimately there will be a point that the sun still sets, but not completely, right?&lt;/p&gt;&#xA;&lt;h1&gt;For the sunrise:&lt;/h1&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;For the purposes of our question, this is not a sunset:&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/T3l0r.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/T3l0r.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The phrase &lt;em&gt;for our purposes&lt;/em&gt; strengthen my doubt that he is being serious. The logic is the same above.&lt;/p&gt;&#xA;&lt;p&gt;But these two illustrations are in the series of other apparently amusing ones, which are the sun as the cell in division, or as the egg in hatching (if you read the book, you will see this effect stronger).&lt;/p&gt;&#xA;&lt;p&gt;So, is there an instance where the sun sets or rises partly, then return back?&lt;/p&gt;&#xA;" OwnerUserId="4945" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-06-27T02:00:26.477" Title="Is there an instance where the sun sets or rises partly, then return back?" Tags="|sun|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9770" PostTypeId="2" ParentId="9769" CreationDate="2017-02-23T13:28:56.637" Score="13" Body="&lt;p&gt;Yes, such sunrises happens every year at the beginning and end of the polar nights at high latitudes. One can have a few days with a glimpse of the sun but disqualified sunsets and sunrises. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sunsets occur at the end of the midnight sun period by the end of the summer, the first sunset is not complete. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/V15P7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/V15P7.jpg&quot; alt=&quot;My own picture from Svalbard. Firs sunrise at Tempelfjorden.&quot;&gt;&lt;/a&gt;&#xA;&lt;em&gt;Sun at it's highest elevation at midday. (To be honest, the picture might be taken the day after the first sunrise, as some mountains are hiding the horizon.)&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is e.g. an article from Svalbardsposten, the northernmost newspaper in the world, reporting of the &lt;a href=&quot;http://svalbardposten.no/nyheter/stralende-tjuvstart/19.3182&quot; rel=&quot;nofollow noreferrer&quot;&gt;first rays of sunlight after the polar night&lt;/a&gt; and some pictures from the &lt;a href=&quot;http://peopleinthestreet.se/2016/december/arets-sista-soluppgang-och-norrsken.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;last sunrise/sunset&lt;/a&gt; before the polar night in northern Sweden. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same occurs at the southern polar circle and south thereof, unless it's &lt;a href=&quot;http://www.antarctica.gov.au/living-and-working/stations/davis/this-week-at-davis/2016/this-week-at-davis-22-july-2016/the-sun-returns&quot; rel=&quot;nofollow noreferrer&quot;&gt;cloudy&lt;/a&gt;... &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Update: here is a great time laps from Davis Station in the Vestfold Hills showing exactly what you asked about: &lt;a href=&quot;https://m.youtube.com/watch?v=2xAxXPWGMiE&amp;amp;feature=youtu.be&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mid winter&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-06-27T02:00:26.477" LastActivityDate="2017-06-27T02:00:26.477" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9771" PostTypeId="2" ParentId="9738" CreationDate="2017-02-23T15:26:04.183" Score="1" Body="&lt;p&gt;This is Oceania according to this Norwegian meteorological website &lt;a href=&quot;https://www.yr.no/place/Oceania/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.yr.no/place/Oceania/&lt;/a&gt;.&#xA;As you can see, it is a quite a large area.&#xA;The website has a very precise weather forecast for almost every place on Earth. The continent is Australia and the area of the Earth is Oceania.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="2470" LastEditDate="2017-02-23T16:31:39.540" LastActivityDate="2017-02-23T16:31:39.540" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9773" PostTypeId="2" ParentId="9764" CreationDate="2017-02-23T16:33:17.537" Score="3" Body="&lt;p&gt;This is a very interesting topic, since climate and land surface model is becoming more powerful and with higher resolution data available, it is possible to include urban land tiles in the model. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The biggest difference of urban region and natural region is the surface albedo and heat capacity. Buildings and roads with dark surfaces have a lower albedo and absorb more sunlight and heat. Building material especially concrete has a lower specific heat capacity than the natural vegetation, it can heat up easily and warm the surrounding at night, which create the heat island effect. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;High rise buildings cluster in the city centre also create an urban boundary layer on the near surface atmosphere, this has altered the wind speed and hence affect evapotranspiration and the heat diffusion. Consequently it also traps air pollutants causing photochemical smog. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Traffic and factories in urban area create high concentration of aerosol, NOx, CH4 and it produces ozone through secondary pollution. Ozone gases at the troposphere is extremely dangerous to living organism, it can trigger asthma and reduce plants' photosynthesis. The dust and PM2.5 particles could also induce higher precipitation because it acts as hygroscopic nuclei for rain droplets to form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Urban area is usually built with efficient drainage system to avoid flooding. This however reduce the evaporation and transpiration from rain event and cause lower relative humidity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These properties of urban area are incorporate into the land surface model. One of the model that did this is the Joint UK Land Environment Simulator (JULES). It has a land tile that is specifically dedicated to urban area &lt;a href=&quot;http://jules.jchmr.org/sites/jules.jchmr.org/files/Young_0.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;[Young, 2014, presentation]&lt;/a&gt;. &#xA;It can be used to test the urban canyon effect, heat island effect and the impact of building green roofs and sky garden etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More detail about the model can be found here: &lt;a href=&quot;http://jules.jchmr.org/content/about#overview&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://jules.jchmr.org/content/about#overview&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7482" LastEditorUserId="7482" LastEditDate="2017-07-31T17:14:58.697" LastActivityDate="2017-07-31T17:14:58.697" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9774" PostTypeId="2" ParentId="9752" CreationDate="2017-02-23T16:39:18.753" Score="0" Body="&lt;p&gt;On a related note, there is another method, still being refined, that uses geodesy, the science of precisely measuring the shape of the earth and its gravity field.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Researchers have dotted California, and much of the seismically active United States, with GPS stations that can provide precise measurements of their distance from each other and their altitude, information which is useful for gauging movement along faultlines. But &lt;a href=&quot;https://www.scientificamerican.com/article/epic-drought-in-west-is-literally-moving-mountains/&quot; rel=&quot;nofollow noreferrer&quot;&gt;researchers noticed during the past decade and a half that stations in drought-ridden areas had increased in altitude&lt;/a&gt; -- as the mass of water in the ground was decreasing, the land surface itself was rising up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Abstract for &lt;a href=&quot;http://dx.doi.org/10.1126/science.1260279&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ongoing drought-induced uplift in the western United States&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The western United States has been experiencing severe drought since&#xA;  2013. The solid earth response to the accompanying loss of surface and near-surface water mass should be a broad region of uplift. We use&#xA;  seasonally-adjusted time series from continuously operating GPS&#xA;  stations to measure this uplift, which we invert to estimate mass&#xA;  loss. The median uplift is 4 mm, with values up to 15 mm in&#xA;  California’s mountains. The associated pattern of mass loss, which&#xA;  ranges up to 50 cm of water equivalent, is consistent with observed&#xA;  decreases in precipitation and streamflow. We estimate the total&#xA;  deficit to be about 240 Gt, equivalent to a 10 cm layer of water over&#xA;  the entire region, or the annual mass loss from the Greenland Ice&#xA;  Sheet.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I was at a seminar last month where one of the researchers talked about using the same methodology to measure the mass increase from the ongoing storms in California, but I think it's too soon for any published research.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The GRACE satellite system also provides groundwater mass estimates. &lt;a href=&quot;http://www.hcn.org/articles/technology-groundwater-california-drought-water-h20radio&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's a general-interest article from last year.&lt;/a&gt; And some researchers at Arizona State University are &lt;a href=&quot;https://asunow.asu.edu/20170118-nasa-satellites-aid-asu-researchers-california-drought-study&quot; rel=&quot;nofollow noreferrer&quot;&gt;using GRACE mission data to study the California drought.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2017-02-23T16:39:18.753" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9775" PostTypeId="2" ParentId="9752" CreationDate="2017-02-23T18:41:47.570" Score="2" Body="&lt;p&gt;You could use gridded model forecasts or reanalysis data to calculate the total water that precipitated. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mathematically, the quantity you desire can be expressend by $$Q=\int_{t_0}^{t_1}\Big[\iint\limits_A R(x,y,t)dxdy\Big]dt=\iint\limits_A P(x,y)dxdy$$&#xA;where $R$ is your precipitation rate, $P$ is your accumulated precipitation, and $Q$ is your desired quantity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One possible way of computing that quantity (In a crude Riemannian method):&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Get reanalysis data of accumulated rainfall, or interpolate observations (&lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/model-data/model-datasets&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOMADS&lt;/a&gt; is a good resource)&lt;/li&gt;&#xA;&lt;li&gt;Read in the precipitation data, adjusting the values over multiple times, if needed.&lt;/li&gt;&#xA;&lt;li&gt;Isolate the data associated with the gridpoints over your area of interest *(such as California).&lt;/li&gt;&#xA;&lt;li&gt;Sum the accumulated rainfall over all of your chosen gridpoints, and multiply the accumulated rainfall by the product of the resolution of the data (in inches). That should get you your data in cubic inches.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-02-23T18:41:47.570" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9778" PostTypeId="2" ParentId="9762" CreationDate="2017-02-24T01:31:35.963" Score="4" Body="&lt;p&gt;A vent opens through the side of a volcano, somewhere on its slopes. The crater (and neck) can seal itself up, solidify over a period of inactivity, then re-open anew nearby to form a new crater. Magma will more readily move through the interface between a solidified neck and surrounding ash matrix than it will through the center of a solidified neck alone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pNRF4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pNRF4.png&quot; alt=&quot;Multiple craters atop Olympus Mons&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7333" LastEditorUserId="6031" LastEditDate="2020-03-08T10:36:07.397" LastActivityDate="2020-03-08T10:36:07.397" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="9779" PostTypeId="2" ParentId="9752" CreationDate="2017-02-24T01:46:00.733" Score="2" Body="&lt;p&gt;NASA's Global Precipitation Measurements Missions can measure rainfall from space: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Visible and infrared space-borne sensors can provide precipitation information inferred from cloud-top radiation, and microwave sensors provide direct precipitation measurement based on radiative signatures of precipitating particles.  This type of information is not available through ground-based measuring systems. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://pmm.nasa.gov/extreme-weather/mudslides-flooding-produced-extreme-rainfall-over-southern-california&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA's Integrated Multi-satellitE Retrievals for GPM (IMERG) were used to estimate the total amount of rain that fell over the western United States from January 17-24, 2017. Rainfall totals of over 9 inches (228.6 mm) were shown in some areas. IMERG rainfall totals have been adjusted to reflect observed values in other similar extreme rainfall events.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You'll need to dig through the site to &lt;a href=&quot;https://pmm.nasa.gov/data-access&quot; rel=&quot;nofollow noreferrer&quot;&gt;find the correct dataset and format&lt;/a&gt;, but it's likely in there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NOAA also does a pretty good job of tracking ground-based measurements here: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.cnrfc.noaa.gov/monthly_precip.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Monthly Precipitation Summary Water Year 2017&lt;/strong&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We'll need to wait for the end of the month before the February numbers are posted, though. As for daily-tracked precipitation data, you can see that here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.wrh.noaa.gov/cnrfc/rsa_getprod.php?prod=RNORR5RSA&amp;amp;wfo=cnrfc&amp;amp;version=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Hydrology-meteorology Data Report&lt;/strong&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7333" LastEditorUserId="7333" LastEditDate="2017-02-24T02:10:34.217" LastActivityDate="2017-02-24T02:10:34.217" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9780" PostTypeId="1" CreationDate="2017-02-24T09:11:50.210" Score="2" ViewCount="81" Body="&lt;p&gt;Although air molecules have an average speed of about 1,500 km/h if there is no wind the air would stay still. The reason for that is that the directions of the molecules cancel each other out. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But is there a probability that wind arise because a majority of the molecules get the same direction? Or is this only theoretically possible?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="5372" LastEditDate="2017-02-24T09:36:45.640" LastActivityDate="2017-02-26T09:02:28.670" Title="Can winds also arise due to a statistical probability that more air molecules suddenly gets an equal direction?" Tags="|meteorology|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="9783" PostTypeId="2" ParentId="9764" CreationDate="2017-02-25T04:24:21.870" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Now, What challenges and possibilities are there in this particular&#xA;  research field?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Now that urban effects on regional weather can be observed, modeled, and to a large degree verified, all that remains on the science side is improving forecast resolution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Serious work, however, is being done on the policy side given these new cause and effect scenarios, although how seriously this effort is being taken is largely nation-dependent: China's response to Beijing's consequences of creating its UHI is a lot different than how the US responds to Atlanta's.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To give you another example, consider how basic mortality data for a heat wave is tabulated for Paris versus New York City. For similar events, Paris records heat-related deaths that are &lt;strong&gt;orders of magnitude&lt;/strong&gt; higher than in NYC, for the simple reason that in NYC, according to city records, the elderly die of &quot;natural causes&quot; regardless of weather. By contrast, in Paris, if a spike in deaths is concurrent with a weather event, the weather event is held accountable.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-02-25T04:24:21.870" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9784" PostTypeId="2" ParentId="9748" CreationDate="2017-02-25T06:26:18.220" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Ocean plates subduct beneath continental plates. Does this make the oceanic plates stretch and become thinner so that the elevation of the sea flow is lower?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;When a continental plate collides with an oceanic plate, or when two oceanic platers collide, the result is subduction of an oceanic plate. This subduction makes oceanic crust recycle rather than build up over time. When two continental plates collide, the result is the Himalayas and the Tibetan plateau. Continental crust isn't recycled to anywhere near the extent that oceanic crust is. Excluding the rather rare ophiolites, the oldest continental crust is about 20 times older than is the oldest oceanic crust.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This quick recycling of oceanic crust versus the slow build up of continental crust is the primary reason that oceanic crust currently is considerably thinner than is continental crust. The very first continents would have had have had fairly thin crusts. Continental crust has become thicker and thicker through the ages, while oceanic crust has not and cannot thanks to subduction.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2017-02-25T17:15:39.903" LastActivityDate="2017-02-25T17:15:39.903" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9785" PostTypeId="2" ParentId="4322" CreationDate="2017-02-25T11:51:26.060" Score="1" Body="&lt;p&gt;I am also getting negative relative humidity from the GFS (Global Forecast System): 36-hour predicted atmosphere dataset (Provider: NOAA/NCEP/EMC, their website: &lt;a href=&quot;http://www.emc.ncep.noaa.gov/index.php?branch=GFS&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.emc.ncep.noaa.gov/index.php?branch=GFS&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found this link that answers as to why relative humidity is possible in their dataset: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://ftp.cpc.ncep.noaa.gov/wd51we/reanal/random_notes/negative.h2o&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://ftp.cpc.ncep.noaa.gov/wd51we/reanal/random_notes/negative.h2o&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This might apply to the one you have access too. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let me know if this helps.&lt;/p&gt;&#xA;" OwnerUserId="7577" LastActivityDate="2017-02-25T11:51:26.060" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9786" PostTypeId="1" CreationDate="2017-02-25T14:10:29.113" Score="8" ViewCount="153" Body="&lt;p&gt;What kinds of vertical ocean mixing measuring instruments are available? This answer &lt;a href=&quot;https://earthscience.stackexchange.com/questions/6612/how-to-measure-ocean-vertical-velocity&quot;&gt;How to measure ocean vertical velocity?&lt;/a&gt; tells about the measurement of vertical velocity by ADCP, but they give very noisy vertical velocities and hence almost unusable (at least in my case in the Bay of Bengal in India). Also I am interested in vertical velocities in the upper ocean with mixed layer depths of 30 to 50 meters and this is where many different things happen (e.g. fish, air bubbles etc.). Has anyone done direct vertical speed measurements in the upper ocean? I am unable to find a good lead.&lt;/p&gt;&#xA;" OwnerUserId="7478" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2018-03-30T21:08:48.157" Title="Direct measurments of vertical ocean mixing?" Tags="|ocean|oceanography|measurements|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9787" PostTypeId="1" AcceptedAnswerId="9821" CreationDate="2017-02-25T16:18:57.973" Score="3" ViewCount="386" Body="&lt;p&gt;What statistical tools are best analysing rainfall data (overall trends, decadal trends, intensity distribution, extremes, etc.)?&lt;/p&gt;&#xA;" OwnerUserId="735" LastEditorUserId="6298" LastEditDate="2017-02-26T13:32:31.533" LastActivityDate="2017-03-03T12:05:09.450" Title="What statistical methods are best for analyzing long-term rainfall data?" Tags="|meteorology|rainfall|statistics|data-analysis|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="9788" PostTypeId="2" ParentId="9780" CreationDate="2017-02-26T09:02:28.670" Score="1" Body="&lt;p&gt;This is perhaps more of a physics question than an earth science one. Thus, answering with the caveat that I am not a practicing physicist:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, it's possible. But it's VERY unlikely. Without doing the maths, I'm guessing &quot;probably won't happen in the lifetime of the universe&quot; unlikely. The reason for this is that there are a LOT of molecules in any macro-scale parcel of air, and a huge majority of them would all have to randomly move the same way at the same time. (plus, I'm guessing there are some Newton third-law, ie action &amp;amp; reaction, reasons why a spontaneous mass movement wouldn't really work) &lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2017-02-26T09:02:28.670" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9790" PostTypeId="1" CreationDate="2017-02-26T17:15:05.197" Score="1" ViewCount="315" Body="&lt;p&gt;Geology: What's make a group of bed a formation?&lt;/p&gt;&#xA;" OwnerUserId="7538" LastActivityDate="2017-02-27T15:45:44.307" Title="Geology: What's make a group of bedrock a formation?" Tags="|geology|bedrock|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9791" PostTypeId="2" ParentId="9790" CreationDate="2017-02-26T19:01:24.353" Score="2" Body="&lt;p&gt;According to Wikipedia, and perfectly consistent with basic historical geological textbooks, a formation is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Geological_formation&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;...the fundamental unit of lithostratigraphy. A formation consists of a certain number of rock strata that have a comparable lithology, facies or other similar properties. ... The concept of formally defined layers or strata is central to the geologic discipline of stratigraphy.&lt;/strong&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dhwZU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dhwZU.jpg&quot; alt=&quot;A geologic cross section of the Grand Canyon. Black numbers correspond to groups of formations and white numbers correspond to formations.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Geological_formation&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;A geologic cross section of the Grand Canyon. Black numbers correspond to groups of formations and white numbers correspond to formations.&lt;/strong&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Typically, formations are traceable across some distance.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-02-26T19:01:24.353" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9797" PostTypeId="2" ParentId="9790" CreationDate="2017-02-27T15:45:44.307" Score="5" Body="&lt;p&gt;Basically a formation is just a layer or group of layers of rock that is both distinct enough to be identifiable in the field and large enough to show up on a geological map. Usually it is many nearly identical layers grouped together or just one large layer. Its not a hugely precise definition but it is a lot like the term &quot;species&quot; in biology, it's a working definition, created more for usability than precision.    &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2017-02-27T15:45:44.307" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9798" PostTypeId="2" ParentId="9549" CreationDate="2017-02-27T20:39:05.010" Score="2" Body="&lt;p&gt;There is no comparing the chemical composition of &quot;atmosphere&quot; with that of mantle rocks and the consequences of rising in each have almost nothing to do with one another. The cooling of rising atmosphere is a fairly simple thermodynamic process requiring neither molecular change of ingredients, chemical release of water, nor thermally impervious boundaries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By contrast, rising mantle materials will undergo different melting processes depending on their water content and chemistry. In the simplest case, like a mid-ocean hot-spot, unpolluted by melt fluxes like water and carbonates, rising mantle rock undergoes &quot;decompression melting&quot; in which 2 things happen:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) The pressure needed to keep rising mantle material solid is released and the material becomes liquid (like that crudely drawn by Michael, above). Remember, given enough pressure, you can heat up ANYTHING and keep it solid...even hydrogen, like that believed to exist in the earth's core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Constituent minerals undergo phase (mineralogical) changes on their way up to the base of the upper crust. Remember that mantle materials come to the earth's surface as basalts which are mineralogically different from the olivene-rich peridotites of the mantle. Despite being chemically similar, deep mantle rocks contain minerals that are crystallographically denser than those found basalts. As they are brought up, these minerals undergo a phase change that alters their crystalline structure; they become different minerals, lighter and more buoyant, further reducing the density of the rising melt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, there it is (in a nutshell): reducing pressure on hot solid material allows it to become liquid and also invokes phase changes in minerals that make the overall material less dense.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-02-27T20:39:05.010" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9800" PostTypeId="1" CreationDate="2017-02-28T10:37:11.300" Score="4" ViewCount="4516" Body="&lt;p&gt;This sort of comes from my &lt;a href=&quot;https://earthscience.stackexchange.com/questions/8806/are-there-any-saltwater-rivers-on-earth&quot;&gt;related question&lt;/a&gt;, but only sort of. Are there any areas on Earth with &lt;strong&gt;purplish-colored soil?&lt;/strong&gt; The purple tint would come from some mineral, perhaps deposited by rivers or volcanic activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know exactly what mineral. The only purple mineral I know for sure is amethyst. It does not hafta be pure purple. A purple-brown mix would be just fine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The line &quot;purple mountains majesty&quot; comes to mind here, but that appears to be just a reddish/purplish sunset reflecting off of brown mountains. I'm looking for something real in the soil/rock, not an illusion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Purplish sand and purplish rock are okay too. Really whatever the land is, that's what I'm asking for purple color.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One more semi-reference: Apollo 17 actually discovered orange soil on the Moon.&lt;/p&gt;&#xA;" OwnerUserId="2733" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2024-01-22T03:11:00.257" Title="Are there any areas on Earth with purplish-colored soil/sand/rock/land?" Tags="|mineralogy|soil|minerals|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9801" PostTypeId="2" ParentId="9800" CreationDate="2017-02-28T16:52:33.400" Score="11" Body="&lt;p&gt;&lt;a href=&quot;http://www.isric.org/sites/all/modules/pubdlcnt/pubdlcnt.php?file=/isric/webdocs/docs/soilbrief_cn04.pdf&amp;amp;nid=336&quot; rel=&quot;noreferrer&quot;&gt;Soil color&lt;/a&gt; is highly dependant on the oxides and other minerals in the composition.  Purplish tones appear to be possible by inclusion of manganese oxide compounds.  There are &lt;a href=&quot;http://www.isric.org/sites/all/modules/pubdlcnt/pubdlcnt.php?file=/isric/webdocs/docs/soilbrief_cn04.pdf&amp;amp;nid=336&quot; rel=&quot;noreferrer&quot;&gt;locations in China&lt;/a&gt; that have markedly violet soils. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you broaden your search to sands as well as soils, there are plenty of examples of garnet-based sands that can appear markedly purple.  California's &lt;a href=&quot;http://www.latimes.com/travel/deals/la-trb-offbeat-traveler-pfeiffer-beach-20110713-photogallery.html&quot; rel=&quot;noreferrer&quot;&gt;Pfeiffer Beach&lt;/a&gt; is one such location.&lt;/p&gt;&#xA;" OwnerUserId="7589" LastEditorUserId="543" LastEditDate="2017-03-01T02:42:31.570" LastActivityDate="2017-03-01T02:42:31.570" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9802" PostTypeId="1" CreationDate="2017-02-28T22:36:10.290" Score="1" ViewCount="179" Body="&lt;p&gt;I'm looking to calculate the total stress at a depth of 10 km in a rock column, where porosity varies with depth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I believe I can figure this out, however I might have copied down an equation wrong. In the equation for total stress I need to know the density of the sediment, so I have to calculate that first. The equation in question is as follows:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Density of Sediment = Density of water * porosity + density of grain * (1 - porosity) * .052 m3/s&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The .0052 m3/s is whats throwing me off, as I end up trying to add the units kg/m3 to kg/s, which can't happen. What I'm thinking is that he might have said &quot;Cubic meters per section&quot; or I'm just way off. Any help would be appreciated&lt;/p&gt;&#xA;" OwnerUserId="7604" LastEditorUserId="7604" LastEditDate="2017-02-28T23:30:11.500" LastActivityDate="2017-02-28T23:30:11.500" Title="Calculate Total stress" Tags="|geology|hydrology|hydrogeology|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9803" PostTypeId="2" ParentId="9544" CreationDate="2017-03-01T04:16:46.300" Score="1" Body="&lt;p&gt;It will vary, but &lt;em&gt;in general&lt;/em&gt; it will be windier on a mountain than in a valley.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An explanation: What slows down wind? Friction. In the valley, there is more friction than on the mountain. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that the fastest wind gust in the US was recorded on Mount Washington with a 200 knot gust. On Mount Washington, buildings have to be chained down to the ground, to prvent destruction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now there are scenarios that the valley is windier than the mountain. Examples include downslope windstorms, and valley breezes. However, if you were to look at climatology, friction would likely play the largest factor.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-03-01T04:16:46.300" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9804" PostTypeId="2" ParentId="9544" CreationDate="2017-03-01T10:52:56.047" Score="1" Body="&lt;p&gt;The best answer is likely &lt;strong&gt;both&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Typically during the day, your first drawing is closer to accurate, particularly as the day goes on.&lt;/li&gt;&#xA;&lt;li&gt;But later in the night, your second drawing is more accurate.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;A big key is that in general winds are typically stronger aloft.  This is because friction dissipates wind at the surface.  And winds, particularly in the mid-latitudes, are reasonably strong aloft in most places.  It does vary some from place to place and from time to time, but this is the general trend.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given that, a central contribution is mixing.  During the day, the ground often begins to warm, and pockets of air start to rise and mix up the atmosphere.  This causes the winds to increase at near-ground level because it mixes those higher winds down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But at night, as the atmosphere cools, the lowest levels start to cool first, and so the ground layer &quot;decouples&quot; from the rest of the atmosphere, such that it stops mixing with the air aloft.  Winds typically drop off.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is important in how the atmosphere can cool quickly under clear conditions (where the warmth radiates away quickly, and the unmixed layer deepens)... and in why tornadoes are much more unlikely at night.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since we're drawing, I attempted to sketch an idea of how vertical winds change as the day goes on, and then progresses on into the night:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/djULN.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/djULN.png&quot; alt=&quot;PBL Drawing&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Notice how the ground winds are usually highest in the afternoon and evening, as mixing averages out with the winds higher up, before reducing as the night goes on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So when talking about regions near mountains... during the day, there is a lot more motion in general.  And thus stronger winds mix down into the valley.  Plus, often as that stronger wind flows up the mountainside, they'll cool too much, and sink back into the valley.  So winds from above affect the valley, and winds from the sides likely affect it more as well.  At many times there may not be as much of the up and down as you've drawn... but other than that, it looks more like your top figure because of the mixing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whereas at night, wind near the surface start to calm.  In valleys, the additional blocking of winds often cause it to calm even more quickly, as there quickly isn't even horizontal mixing to keep things active.  That's why at night even small valleys can often get quite a bit colder than surrounding areas on nights where there's little synoptic wind [wind due to larger storm systems].  But even on most slightly windy evenings, it's likely that the winds in valleys are calmer than on the mountains (which tend to be much higher than other places on Earth), and also probably calmer than similar areas in the Plains.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-03-01T11:02:09.893" LastActivityDate="2017-03-01T11:02:09.893" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9805" PostTypeId="1" AcceptedAnswerId="9807" CreationDate="2017-03-01T11:05:26.197" Score="6" ViewCount="5734" Body="&lt;p&gt;There is &lt;a href=&quot;https://climate.nasa.gov/evidence/&quot; rel=&quot;nofollow noreferrer&quot;&gt;reasonable evidence&lt;/a&gt; to suggest that the Earth is warming. The most probable cause appears to be increased &lt;a href=&quot;https://en.wikipedia.org/wiki/Greenhouse_effect#Role_in_climate_change&quot; rel=&quot;nofollow noreferrer&quot;&gt;CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere&lt;/a&gt;, which has been reasoned about for &lt;a href=&quot;https://en.wikipedia.org/wiki/Svante_Arrhenius#Greenhouse_effect&quot; rel=&quot;nofollow noreferrer&quot;&gt;quite some time&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There appear to have been some volcanic eruptions in the 1200s that lead to a &lt;a href=&quot;https://en.wikipedia.org/wiki/Little_Ice_Age#Volcanic_activity&quot; rel=&quot;nofollow noreferrer&quot;&gt;mini-ice age&lt;/a&gt;. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Stratospheric_sulfur_aerosols&quot; rel=&quot;nofollow noreferrer&quot;&gt;cause&lt;/a&gt; appears to be increased sulfur dioxide (S02) in the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could we &lt;a href=&quot;https://www.wired.com/2008/06/ff-geoengineering/&quot; rel=&quot;nofollow noreferrer&quot;&gt;engineer&lt;/a&gt; this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: &lt;strong&gt;Would adding sulfur dioxide to the atmosphere have a global cooling effect?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="895" LastEditorUserId="2536" LastEditDate="2017-05-28T10:06:04.273" LastActivityDate="2022-01-22T10:27:11.017" Title="Would adding sulfur dioxide to the atmosphere have a global cooling effect?" Tags="|climate-change|climate-models|geoengineering|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9806" PostTypeId="2" ParentId="9805" CreationDate="2017-03-01T12:06:40.740" Score="2" Body="&lt;p&gt;One of the issues with adding sulfur dioxide to the air is that it produces &lt;a href=&quot;https://en.wikipedia.org/wiki/Acid_rain&quot; rel=&quot;nofollow noreferrer&quot;&gt;acid rain&lt;/a&gt;, which in the past has had a &lt;a href=&quot;http://chemistry.elmhurst.edu/vchembook/196forests.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;detrimental effect on forests&lt;/a&gt;. This was a major issue during the 1960s to 1990s and it is &lt;a href=&quot;http://www.dw.com/en/germany-controversially-still-bombards-forests-with-limestone-to-combat-acid-rain/a-17239231&quot; rel=&quot;nofollow noreferrer&quot;&gt;still an issue&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One area that was badly affected, and is still dealing with the effects of acid rain is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Black_Forest&quot; rel=&quot;nofollow noreferrer&quot;&gt;Black Forest&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-03-01T12:06:40.740" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9807" PostTypeId="2" ParentId="9805" CreationDate="2017-03-01T16:08:12.103" Score="9" Body="&lt;p&gt;There have been a range of studies on the issue published in &lt;a href=&quot;http://www.atmospheric-chemistry-and-physics.net/index.html&quot; rel=&quot;noreferrer&quot;&gt;Atmospheric Chemistry and Physics&lt;/a&gt; and other scientific journals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The short answer is &quot;yes.&quot; The longer answer is &quot;yes, but....&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In &lt;a href=&quot;http://www.atmos-chem-phys.net/16/2843/2016/&quot; rel=&quot;noreferrer&quot;&gt;Climatic impacts of stratospheric geoengineering with sulfate, black carbon and titania injection&lt;/a&gt;, Jones, et. al. (2016) note: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In this paper, we examine the potential climatic effects of&#xA;  geoengineering by sulfate, black carbon and titania injection against&#xA;  a baseline RCP8.5 scenario. We use the HadGEM2-CCS model to simulate&#xA;  scenarios in which the top-of-the-atmosphere radiative imbalance due&#xA;  to rising greenhouse gas concentrations is offset by sufficient&#xA;  aerosol injection throughout the 2020–2100 period. We find that the&#xA;  global-mean temperature is effectively maintained at historical levels&#xA;  for the entirety of the period for all three aerosol-injection&#xA;  scenarios, &lt;strong&gt;though there is a wide range of side-effects which are&#xA;  discussed in detail&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Those side-effects would vary with the size of the particles used and the method and location of atmospheric injection, but would include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Impacts on human health from increased particulates.&lt;/li&gt;&#xA;&lt;li&gt;Changes in surface albedo from particulate deposition. &lt;/li&gt;&#xA;&lt;li&gt;Changes in the amount and location of precipitation across the globe. &lt;/li&gt;&#xA;&lt;li&gt;Increased stratospheric warming.&lt;/li&gt;&#xA;&lt;li&gt;Changes in stratospheric ozone levels.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;There would be no amelioration for other climate impacts such as ocean acidification.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It is therefore important to note that the safest possible solution to&#xA;  avoiding the sort of climate change instantiated by, e.g., Fig. 6a of&#xA;  this report is to effectively mitigate greenhouse-gas emissions.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Other issues not addressed by this physics-based paper include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The requirement for any geoengineering scheme to be maintained for decades or centuries.&lt;/li&gt;&#xA;&lt;li&gt;The need for a substantial industrial base to manufacture and distribute the particulates involved.&lt;/li&gt;&#xA;&lt;li&gt;The (presumed) need for an international body to manage the process and address political concerns such as the costs and benefits of the   geoengineering; such as if the process was going to increase or reduce rainfall to a particular region.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2017-03-01T16:08:12.103" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9808" PostTypeId="2" ParentId="9800" CreationDate="2017-03-01T21:58:15.913" Score="7" Body="&lt;p&gt;Yes, there are. Here are some examples from Southern Israel:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CxpNZ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CxpNZ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NDdpg.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NDdpg.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another exceptional example is the &quot;rainbow mountain&quot; in Peru:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/m2Sfx.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/m2Sfx.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cause of these colours is the usually trace oxide amount in the soil. The soil is usually composed mostly of silt-sized quartz. This quartz is coated with with various oxides. Differing proportions of these oxides will change the colour of the soil. Fe&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; appears red, Fe&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt; is black and FeO(OH) is yellow. Manganese oxides (with either Mn&lt;sup&gt;2+&lt;/sup&gt;, Mn&lt;sup&gt;3+&lt;/sup&gt;, Mn&lt;sup&gt;4+&lt;/sup&gt;, or mixed valence) can tint soil dark black, or slightly purple when mixed with iron oxides. Clays can also change the colour, with the famous example of green glauconite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Variations of these minerals, grain size, and surrounding colour of the soil (to change your perception) can create just about any colour you can think of, including purple.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-03-01T21:58:15.913" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9809" PostTypeId="2" ParentId="9805" CreationDate="2017-03-02T00:28:39.323" Score="4" Body="&lt;p&gt;SO2 is a gas in the atmosphere, which does not cool the atmosphere.  However, SO2 oxidizes to H2SO4, which gets involved with aqueous chemistry and often leads to sulfate (SO4).  Sulfate is an aerosol that will reflect sunlight (like many aerosols) and block energy input to the Earth.  If you increase the amount of sunlight being reflected back to space (reducing the amount of sunlight absorbed by the surface of the Earth), there is a net cooling affect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, yes, adding sulfur dioxide will have a net cooling affect, since a lot of it will convert to sulfate.  However, increasing sulfur dioxide in the troposphere is the equivalent of polluting the air, which leads to health problems and acid rain problems.  If you could inject sulfates into the stratosphere (which a very explosive volcanic eruption can do) then it won't affect the air we breathe (or cause acid rain) nearly as much.  The real solution, though, to global warming is to limit carbon emissions (e.g. GHGs) so that significant polar ice and snow pack can be retained and do its job of reflecting light back to space.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0021850296000638&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.sciencedirect.com/science/article/pii/S0021850296000638&lt;/a&gt;&#xA;&lt;a href=&quot;http://www4.ncsu.edu/~franzen/public_html/Poland/Poznan08a/Sulfur_Cycle.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www4.ncsu.edu/~franzen/public_html/Poland/Poznan08a/Sulfur_Cycle.pdf&lt;/a&gt;&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Stratospheric_sulfate_aerosols_(geoengineering)&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Stratospheric_sulfate_aerosols_(geoengineering)&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2017-03-02T03:11:52.893" LastActivityDate="2017-03-02T03:11:52.893" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9810" PostTypeId="1" CreationDate="2017-03-02T09:49:24.423" Score="5" ViewCount="128" Body="&lt;p&gt;I am from India, Tamilnadu state. Our nation has planned to have hydrocarbon extraction units in our Thanjavur villages. We, a 70 million people Tamilnadu state get most of our rice from that region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Our government says, An extraction unit requires only 5 acres and it won't affect the nearby farmers or the ground water at all.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some people say Hydrocarbon needs to be extracted from the ground level deeper than that of water. So it requires polluting/draining all the ground water and the process will exterminate agriculture in that area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We do not have reliable rain for decades to farm. We rely mostly on the ground water for food production.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="7590" LastEditorUserId="2470" LastEditDate="2017-03-02T11:38:46.560" LastActivityDate="2017-04-01T12:05:12.137" Title="Do Hydro-Carbon extraction units pollute ground water?" Tags="|hydrology|groundwater|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9811" PostTypeId="1" CreationDate="2017-03-02T09:49:55.633" Score="7" ViewCount="583" Body="&lt;p&gt;I know that things are not as simple, but for the sake of argument I'll assume a &lt;a href=&quot;https://en.wikipedia.org/wiki/Supercontinent_cycle&quot; rel=&quot;noreferrer&quot;&gt;supercontinent cycle&lt;/a&gt; of $\sim$400 Myr periodicity is active on Earth.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If that is the case, then my naive understanding was that roughly all of Earth's crust is reformed on this timescale, and information about the past is forgotten due to melting in the subducted zones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However I stumbled upon a &lt;a href=&quot;http://www.nature.com/nature/journal/vaop/ncurrent/full/nature21383.html&quot; rel=&quot;noreferrer&quot;&gt;research article&lt;/a&gt; that cites &quot;Most exposed continental crust that can be dated back to the Archaean eon (4 billion to 2.5 billion years ago) comprises of...&quot; as summary of &lt;a href=&quot;http://www.nature.com/ngeo/journal/v7/n1/full/ngeo2019.html&quot; rel=&quot;noreferrer&quot;&gt;another article&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So there is a fraction of crust that survives this process and is several cycles old. Do we know the fraction of material in the crust that survived this process?&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="725" LastEditDate="2017-03-02T10:02:36.130" LastActivityDate="2017-07-04T15:10:29.300" Title="What fraction of Earth's crustal material survives the supercontinent cycle?" Tags="|geochemistry|plate-tectonics|earth-history|mantle|crust|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9812" PostTypeId="2" ParentId="9810" CreationDate="2017-03-02T12:01:42.443" Score="3" Body="&lt;p&gt;The types of hydrocarbon extracted from the ground ranges from gas to crude oil and bitumen. Each deposit of hydrocarbon is different; some are all gas whereas others are various types of crude oil or mixtures of oil and gas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Extraction methods also vary depending on the style of geology containing the hydrocarbon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geology with relatively large spaces between the grains of the rock, such as sandstone, may have hydrocarbons that can flow easily. This type of deposit represents the classical oil deposits, such as in Saudi Arabia. Generally, with such deposits, holes are drilled into the deposit and oil is pumped out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geology with very tight spaces, such as shale, do not have the conditions for hydrocarbons to flow easily. In this type of geology the rock needs to be fractured to allow the hydrocarbon fluids to flow more easily. To achieve this a relatively new technique called fracking is used to fracture the rock containing the deposit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both classical hydrocarbon extraction and fracking require the use of drill holes to access the deposit. If the deposit of hydrocarbon occurs below a water aquifer, or other form of ground water storage, the drill holes that access the hydrocarbon deposit will pass through the underground water store.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To prevent the hydrocarbon wells (drill holes) from contaminating the water lying above them, the wells need to be cased (lined). The casing of hydrocarbon wells needs to be done by people who are committed to doing so and who are extremely competent in doing such tasks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nothing is ever perfect and there will always be risks of well casing failing which would result in ground water contamination. It then becomes a question how large is the risk, what will be the effect of such a risk and who is prepared to take such risks.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-03-02T12:01:42.443" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9813" PostTypeId="1" AcceptedAnswerId="9817" CreationDate="2017-03-02T12:23:40.657" Score="29" ViewCount="8533" Body="&lt;p&gt;It can rain all day, and it can snow for hours on end, but hail always seems to fall for short periods only. Why don't you get prolonged periods of hail?&lt;/p&gt;&#xA;" OwnerUserId="1191" LastActivityDate="2017-03-03T09:53:45.817" Title="Why are hail storms always brief?" Tags="|meteorology|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9814" PostTypeId="2" ParentId="9813" CreationDate="2017-03-02T13:09:54.983" Score="28" Body="&lt;p&gt;Hail is created within a thunderstorm by updrafts that carry water droplets to an altitude where temperatures are lower than the freezing point for water (32°F or 0°C). This freezing process forms a hailstone.  This process can repeat itself each time increasing the size of the hailstone until the hailstones become too heavy to be picked up again.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The creation of hail requires high wind speeds that may only be sustained in the storm for a brief period of time.  Longer periods of hail are possible but typically require large strong storms such as tornadic supercell thunderstorms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&#xA;   &lt;a href=&quot;http://www.everythinglubbock.com/weather/hail&quot; rel=&quot;noreferrer&quot;&gt;How hail is created.&lt;/a&gt;&#xA;   &lt;a href=&quot;http://snrclimatecorner.blogspot.com/2010/07/intense-updrafts-needed-for-hail.html&quot; rel=&quot;noreferrer&quot;&gt;Size of Hail vs wind speed&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3iSC6.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3iSC6.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ApirS.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ApirS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="4789" LastEditDate="2017-03-02T17:59:35.400" LastActivityDate="2017-03-02T17:59:35.400" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="9815" PostTypeId="2" ParentId="9813" CreationDate="2017-03-02T16:05:53.930" Score="4" Body="&lt;p&gt;The other answer is correct: the mechanism of hail formation is the hail repeatedly travels up the cloud, gets heavier, and then when it becomes too heavy, it falls out of the cloud. This process has a number of preconditions such as an updraft and a lot of water, and when those preconditions are disrupted, so is the hailstorm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I want to look at it from a different perspective. Here, let's do an exercise.  Find a fridge with an icemaker, and extract ice from it as rapidly as possible. If your icemaker is like mine, you can get a huge amount of ice out for a very short time, and then you wait a long time for more ice to be made. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is no lack of moisture in an icemaker; the plumbing supplies as much as it needs. And there does not need to be an updraft, obviously.  But in both the hailing cloud and in your icemaker, there has to be &lt;em&gt;some process which is extracting heat from the water and moving it elsewhere in the environment&lt;/em&gt;. And that process takes time and energy. Once all the stored ice is gone, you're going to have to wait, and you're going to have to spend energy to get more.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You have to extract 80 calories of heat from each gram of liquid water to freeze it &lt;em&gt;regardless of the current temperature and pressure of the air&lt;/em&gt;. And it takes an extraction of a whopping 540 calories per gram of water vapor to turn it to liquid, again, regardless of the temperature and pressure.  That heat has to &lt;em&gt;go&lt;/em&gt; somewhere! We think of hail as a massive &lt;em&gt;exportation of coldness&lt;/em&gt; from the cloud, but you can't get coldness somewhere without putting that heat somewhere else. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That heat energy that is somehow extracted is going to change the characteristics of the cloud. And there are real physical limits on how much time and energy it takes to transfer that heat somewhere else in the cloud. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your icemaker has a basically unlimited supply of moisture and perfectly stable conditions for making ice, and once its reserves are gone, it cannot supply a rapid flow of new ice. Even if a cloud had an unlimited supply of moisture and perfect ice making conditions, it also cannot supply a rapid flow of new ice once the reserves are gone. It turns out that it is &lt;em&gt;really expensive&lt;/em&gt; in energy terms to make ice out of water vapor, and so on energy grounds alone we would expect hailstorms to be short.&lt;/p&gt;&#xA;" OwnerUserId="225" LastEditorUserId="225" LastEditDate="2017-03-02T16:12:00.453" LastActivityDate="2017-03-02T16:12:00.453" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9816" PostTypeId="1" CreationDate="2017-03-02T16:48:08.957" Score="10" ViewCount="529" Body="&lt;p&gt;Reading about moons of other planets they often get heated up by the tides so for example Io and Europe of Jupiter get friction by which eruptions and liquid water can arise. But is there also an effect on Earth due to the tides of the moon and sun? If so how many degrees is the Earth heated up?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="111" LastEditDate="2017-03-02T18:14:51.973" LastActivityDate="2017-03-06T14:11:09.433" Title="Is the Earth heated up by the tides?" Tags="|geophysics|tides|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9817" PostTypeId="2" ParentId="9813" CreationDate="2017-03-02T17:09:14.570" Score="11" Body="&lt;p&gt;The first reason is that hail is intimately connected to extreme updrafts in  violent, high-energy, high-wind storms, mostly supercells. High-wind storms by their very nature tend to move quickly, so they go as fast as they came. And for obvious reasons an updraft must be a local phenomenon (or the air in a region would go away). One can have multiple hail storms on any given day when the conditions are right, but each one is necessarily a local phenomenon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So we need to be more precise: Hail storms are short &lt;em&gt;at any given location&lt;/em&gt;, but the storm can be longer lived and create more hail elsewhere, together with tornadoes, hard rain and other short-lived whether phenomena. Sometimes we can see a cell move over land from a distance. We can see that rain or hail continue to fall out of it, but the cell is constantly changing location.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second reason, concerning a somewhat longer timescale, is that the condensation depletes the storm of energy which must be replenished, or the storm dies eventually, as can be seen with hurricanes: They are long-lived only over warm bodies of water which serve as the energy source. Over land they abate quickly. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This would make it possible that there are longer-lived hail storms over the sea, but I have no data about that. A &lt;a href=&quot;http://theweatherprediction.com/habyhints2/403/&quot; rel=&quot;nofollow noreferrer&quot;&gt;remark&lt;/a&gt; on theweatherprediction.com says that hail in hurricanes is rare because the air is so moist and warm (i.e. energy laden) that it freezes too late and too far up.&lt;/p&gt;&#xA;" OwnerUserId="5396" LastEditorUserId="5396" LastEditDate="2017-03-03T09:53:45.817" LastActivityDate="2017-03-03T09:53:45.817" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9818" PostTypeId="1" CreationDate="2017-03-03T01:01:29.087" Score="10" ViewCount="1772" Body="&lt;p&gt;I am trying to understand the footprint of a flight. &#xA;First Wikipedia says (without quoting a source): &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The level and effects of CO2 emissions are currently believed to be broadly the same regardless of altitude.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But then there are numerous references to radiative forcing, which is supposedly almost doubling the effects of the emissions (at this point only co2, or also NOx and others?). These are never explained (it says &quot;see below&quot; once, but there follows no explanation below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The article on radiative forcing says that &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Typically, radiative forcing is quantified at the tropopause in units of watts per square meter of the Earth's surface.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However this does not seem to explain why quantifying it &quot;at the tropopause&quot; makes sense, or what that means, since the measure given is measured on the surface. Does this imply that emissions below / above the tropopause are not considered contributing to radiative forcing? (I presume they are.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, how come that emissions at greater heights force more? After all, at lower heights the same amount can cover a greater surface area at the same thickness / density. Maybe, the change in wavelength of incoming radiation is greater since the traveled distance is greater, and thus more is absorbed?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lastly, does CO2 not ascend after being emitted at surface level, such that it will enter the stratosphere just as well as if it is emitted there? Or are there further factors partially mitigating this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see I have too many questions, and find the Wikipedia articles very unrevealing / lacking.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;" OwnerUserId="7619" LastActivityDate="2023-05-21T16:02:53.383" Title="Why does the emission of aircrafts at higher altitudes have a greater effect on the climate?" Tags="|atmosphere|climate|climate-change|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9819" PostTypeId="2" ParentId="9818" CreationDate="2017-03-03T06:11:39.107" Score="3" Body="&lt;p&gt;Check out &lt;a href=&quot;https://en.wikipedia.org/wiki/Environmental_impact_of_aviation&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Environmental_impact_of_aviation&lt;/a&gt; .   NOx from airplanes near/in the stratosphere increases ozone formation plus aerosols help form contrails... both of which increases warming.  If the airplane emissions aren't in the stratosphere, then the chemistry and lifetime of those non-CO2 emissions are not nearly as potent.  &lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-03-03T06:11:39.107" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9820" PostTypeId="2" ParentId="9816" CreationDate="2017-03-03T10:57:00.227" Score="2" Body="&lt;p&gt;According to &lt;a href=&quot;https://en.wikipedia.org/wiki/Tidal_acceleration#Angular_momentum_and_energy&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt;, the energy lost by Earth in tidal acceleration is about 3.321 TW, most of it (95%) is converted to heat by frictional losses in the oceans and their interaction with the solid Earth, and the rest (0.121 TW) is transferred to the Moon.&lt;/p&gt;&#xA;" OwnerUserId="7613" LastActivityDate="2017-03-03T10:57:00.227" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="9821" PostTypeId="2" ParentId="9787" CreationDate="2017-03-03T12:05:09.450" Score="2" Body="&lt;p&gt;It depends on your data, if the rainfall data is in a grid with temporal and spatial dimension, you can use a NetCDF format to analyse the data via R, matlab, IDL or Python. NetCDF is Network Common Data Form, which is a very common format of grided and temporal data. In Python, you can simply do several 10-year average map to see the long term decadal trend. Or you could plot a transient period of a smaller region with average rainfall to see monthly or seasonally change. To find out the intensity of distribution you could plot a map with a logarithmic scale of colour. Use a threshold to identify extreme rainfall event that is above the threshold. I use a Python package called iris which can easily plot graphs using NetCDF data. You can look at some examples here &lt;a href=&quot;http://scitools.org.uk/iris/docs/latest/gallery.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://scitools.org.uk/iris/docs/latest/gallery.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For getting the rainfall data, you can download the rainfall data from the CRU-NCEP database &lt;a href=&quot;https://crudata.uea.ac.uk/cru/data/hrg/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://crudata.uea.ac.uk/cru/data/hrg/&lt;/a&gt; CRU stand for Climate Research Unit and it has the most accurate historical data available to the public. They are reanalyzed data from meteorological stations and ships. The highest resolution available is 0.5 latitude * 0.5 longitude degree grid. And for temporal resolution they have 6-hourly and daily. The data is in NetCDF format which is a format most map processing data use. If you don't know how to handle ncdf you could use Google Earth as well &lt;a href=&quot;https://crudata.uea.ac.uk/cru/data/hrg/cru_ts_3.23/ge/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://crudata.uea.ac.uk/cru/data/hrg/cru_ts_3.23/ge/&lt;/a&gt; .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To know more how the data is derived you can read this paper. Hope it helps. &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/joc.3711/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://onlinelibrary.wiley.com/doi/10.1002/joc.3711/abstract&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7482" LastActivityDate="2017-03-03T12:05:09.450" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9822" PostTypeId="1" AcceptedAnswerId="13540" CreationDate="2017-03-03T12:12:46.517" Score="13" ViewCount="4630" Body="&lt;p&gt;I'm using ADXL345 accelerometer with Raspberry Pi to build a seismograph. I've successfully hooked it up and can plot the accelerometer data in three axis. Is there any way to express these data in the form of the magnitude of an earthquake, of course, at the point of sensing? I know that it might be imprecise, but any representation would be helpful (e.g. Richter scale), and how to accomplish that.&lt;/p&gt;&#xA;" OwnerUserId="7628" LastEditorUserId="11908" LastEditDate="2018-03-05T17:32:12.523" LastActivityDate="2018-03-06T00:16:08.117" Title="Using accelerometer as a seismograph" Tags="|earthquakes|seismology|instrumentation|in-situ-measurements|diy|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9823" PostTypeId="2" ParentId="9816" CreationDate="2017-03-03T19:30:54.713" Score="6" Body="&lt;p&gt;A good estimate of the lunar tidal energy dissipated into the oceans is 2.5 Terawatts (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0079661197000219?via%3Dihub&quot; rel=&quot;nofollow noreferrer&quot;&gt;Munk, 1997&lt;/a&gt;; &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0079661197000220&quot; rel=&quot;nofollow noreferrer&quot;&gt;Le Provost &amp;amp; Lyard, 1997&lt;/a&gt;). The value estimated comes mainly from two different sources: from harmonic calculations and from altimetry estimates using satellite observations (e.g., &lt;a href=&quot;https://en.wikipedia.org/wiki/TOPEX/Poseidon&quot; rel=&quot;nofollow noreferrer&quot;&gt;Topex/Poseidon&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The input of energy into the coastal ocean is not uniform and has a peak in the South Atlantic Ocean, while the energy is dissipated by bottom friction in the coastal ocean and mainly in the North Atlantic Ocean (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0079661197000220&quot; rel=&quot;nofollow noreferrer&quot;&gt;Le Provost &amp;amp; Lyard, 1997&lt;/a&gt;).&#xA;&lt;a href=&quot;https://i.stack.imgur.com/R7ytb.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/R7ytb.jpg&quot; alt=&quot;Egbert &amp;amp; Ray, Nature, 2000&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: Nature: Egbert &amp;amp; Ray, 2000. Estimates of tidal energy dissipation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/nature/journal/v405/n6788/full/405775a0.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Egbert &amp;amp; Ray (2000)&lt;/a&gt; showed that a fraction of the dissipation (1 TW) takes place in the deep ocean in areas of, generally near areas of rough topography. Maintaining ocean stratification and the large scale thermohaline circulation (the commonly known &quot;Conveyor Belt&quot;) requires around 2 TW to provide enough mixing (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0967063798000703?via%3Dihub&quot; rel=&quot;nofollow noreferrer&quot;&gt;Munk &amp;amp; Wunsch, 1998&lt;/a&gt;). Therefore, the tides provide about half of that energy with the other half coming from wind forcing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a summary figure from &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0967063798000703?via%3Dihub&quot; rel=&quot;nofollow noreferrer&quot;&gt;Munk &amp;amp; Wunsch, 1998&lt;/a&gt;. &lt;a href=&quot;https://i.stack.imgur.com/vFVHQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vFVHQ.jpg&quot; alt=&quot;static.skepticalscience.com&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The repercussion of this fact are given by &lt;a href=&quot;http://www.nature.com/nature/journal/v405/n6788/full/405743a0.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wunsch (2000)&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...it was only recently recognized that the need for an energy source to sustain the vertical mixing (lifting dense water through lighter) has important consequences. The difficulties of driving fluid motions by surface heating and evaporation mean that a mechanical source of energy must control not only the directly wind-driven flows, but also the deep-water components of the meridional overturning circulation. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;... changes in tidal distributions and the consequent mixing would need to be understood over geological time. During the Last Glacial Maximum, the sea level was about 130 metres lower than today. This configuration removed much of the present regions of shallow-water energy dissipation and changed the deep-ocean tides, presumably affecting oceanic heat transport. Over longer periods in the past, the entire continental configuration was different, with radically different tidal distributions and mixing. It appears that the tides are, surprisingly, an intricate part of the story of climate change, as is the history of the lunar orbit.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2017-03-06T14:11:09.433" LastActivityDate="2017-03-06T14:11:09.433" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9826" PostTypeId="1" CreationDate="2017-03-04T05:17:34.437" Score="7" ViewCount="227" Body="&lt;p&gt;In places like the Giant's causeway in Ireland (Antrim basalts) there are columnar basalt flows of 100 metres or more. I'm aware that the cooling mechanism is complex, but is there any rough and ready equation for estimating the cooling time of such a basalt flow?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="111" LastEditDate="2017-03-04T13:19:59.803" LastActivityDate="2018-02-07T22:26:42.757" Title="Cooling time of basalt flows?" Tags="|geophysics|magmatism|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9827" PostTypeId="2" ParentId="9811" CreationDate="2017-03-05T05:13:46.930" Score="1" Body="&lt;p&gt;The fraction that has survived this &quot;supercontinent cycle&quot; is very small and can be found in only a handful of places where it outcrops....generally as part of interior cratons in Canada, Greenland, etc. However, even within these Archaen shield rocks, the volume of &quot;original crust&quot; is itself very small, hard to find, and subject to controversy with respect to chemistry. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Original crustal material that dates back to a pre-tectonic (Hadean) regime would have to have been formed from cooling of molten material and would itself contain a very specific chemical signature that is itself, theorized but not known with certainty.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given how small that volume is, and how difficult it is to access many of these rocks, it's unlikely that anyone will pony up the money for a deep seismological survey of their extent at depth, so, a solid number for volume will not be forthcoming soon.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-03-05T05:13:46.930" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9828" PostTypeId="1" CreationDate="2017-03-05T08:18:35.333" Score="1" ViewCount="43" Body="&lt;p&gt;And what kind of vehicles and drones are used or are planned for now and for near future?&lt;/p&gt;&#xA;" OwnerUserId="7644" LastActivityDate="2017-03-05T18:37:05.730" Title="How are flying drones and unmanned vehicled used for exploring volcanoes?" Tags="|volcanic-hazard|" AnswerCount="1" CommentCount="1" ClosedDate="2017-03-07T20:28:54.217" ContentLicense="CC BY-SA 3.0" />
  <row Id="9829" PostTypeId="2" ParentId="9828" CreationDate="2017-03-05T18:23:21.840" Score="1" Body="&lt;p&gt;Here's a partial answer: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://www.trailbyfire.org&quot; rel=&quot;nofollow noreferrer&quot;&gt;Trail by Fire expedition 1.5&lt;/a&gt; -- &quot;We're a team of young volcanologists planning to measure the entire flux of gases emitted by volcanoes along the Nazca subduction zone.&quot; -- driving through South America has &quot;a fleet of quadcopters with gas sensing and sampling capabilities, establishing a remote presence in the volcanic plumes we encounter along the Trail by Fire.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On &lt;a href=&quot;http://www.trailbyfire.org/gearsponsors/&quot; rel=&quot;nofollow noreferrer&quot;&gt;their sponsors page&lt;/a&gt; they list the science payload for each of three Matrix quadcopters (more details about the mechanisms and some custom kit are on the page), which are used because of the difficulty and hazard of climbing to the vents along the mountain chain and sampling the plumes:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;An Ocean Optics Flame UV-DOAS spectrometer for SO2 measurements&lt;/li&gt;&#xA;&lt;li&gt;A multigas sensor built by INGV (Italy)&lt;/li&gt;&#xA;&lt;li&gt;A gas collector to bring plume gas to the Delta Ray Spectrometer&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;There's also a bit of drone footage included in the videos on &lt;a href=&quot;http://www.trailbyfire.org/news/&quot; rel=&quot;nofollow noreferrer&quot;&gt;their blog page&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that their goal is specifically to understand the gases: &quot;Our objective is to provide the first accurate and large-scale estimate of the flux of volatile species (H2O, H2, CO2, CO, SO2, H2S, HCl, HF, and more) emitted by volcanoes of the Nazca subduction zone.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Disclaimer: I only know about this because one of the researchers worked for my institution during last year's initial expedition. A review of the literature may show more published uses of drones and UAVs beyond simply shooting video.)&lt;/p&gt;&#xA;" OwnerUserId="7314" LastEditorUserId="7314" LastEditDate="2017-03-05T18:37:05.730" LastActivityDate="2017-03-05T18:37:05.730" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9830" PostTypeId="1" CreationDate="2017-03-06T15:49:53.137" Score="3" ViewCount="11936" Body="&lt;p&gt;Most modern windmills appears to rotate clockwise. I know that is has something to do with the direction were the wind is coming from. But how to understand this?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastActivityDate="2017-03-06T18:01:45.730" Title="Why do modern windmills turn clockwise, but classic mills turn counter-clockwise?" Tags="|atmosphere|" AnswerCount="1" CommentCount="2" ClosedDate="2017-03-07T11:49:46.483" ContentLicense="CC BY-SA 3.0" />
  <row Id="9831" PostTypeId="1" CreationDate="2017-03-06T16:17:45.873" Score="1" ViewCount="38" Body="&lt;p&gt;Here is my question. The concentration of atmospheric species is decided by three major components: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The source related to natural or anthropology activities.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The chemical pathway of the formation and removal of this species.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The diffusion and advection of the species with the atmospheric motion.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;To analysis the temporal pattern of one species, e.g, the formation of O3,isolating the chemical reaction as an independent part. I want to eliminate the wind factors (including the wind direction and speed).  &lt;/p&gt;&#xA;" OwnerUserId="5214" LastActivityDate="2017-03-06T16:17:45.873" Title="Is there any method to analysis the variation of chemical species removing the meteorology condition" Tags="|atmosphere|atmospheric-chemistry|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9832" PostTypeId="2" ParentId="9709" CreationDate="2017-03-06T17:34:21.947" Score="1" Body="&lt;p&gt;I found good datasets on the &lt;a href=&quot;http://www.eumetsat.int/website/home/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;EUMETSAT&lt;/a&gt; and &lt;a href=&quot;http://marine.copernicus.eu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CMEMS&lt;/a&gt; websites for anyone else who needs wind direction data. They both have global data sets for both wind speed and direction above the ocean surface and I've found the ASCAT data (available on both sites) to be of a high quality. &lt;/p&gt;&#xA;" OwnerUserId="7367" LastEditorUserId="7367" LastEditDate="2017-03-06T20:40:25.817" LastActivityDate="2017-03-06T20:40:25.817" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9833" PostTypeId="2" ParentId="9830" CreationDate="2017-03-06T18:01:45.730" Score="1" Body="&lt;p&gt;It is to do with the angle of the blade, it has nothing to do with the direction of the wind. If the blade is slightly facing clockwise then the wind will push it to turning anticlockwise. If the blade is slightly facing anticlockwise then the wind will push it up and become clockwise. There is no reason from a physics perspective that governs which direction of rotation is best. Modern wind turbines are manufactured in factories who use the same design of blades, this can reduce the cost of production and present a coherent view. While windmills in the past are produced in small local subsistence workshop and don't have standardization.&lt;/p&gt;&#xA;" OwnerUserId="7482" LastActivityDate="2017-03-06T18:01:45.730" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9835" PostTypeId="1" AcceptedAnswerId="9836" CreationDate="2017-03-06T20:42:30.303" Score="4" ViewCount="1951" Body="&lt;p&gt;Recently I've been working on a debate for climate change and I'm working on a rebuttal statement but then I came across many different sites that claimed that there were higher CO&lt;sub&gt;2&lt;/sub&gt; levels before there was even industrialization or a substantial amount of CO&lt;sub&gt;2&lt;/sub&gt; being made from humans. I just need an explanation on how this happened. &lt;/p&gt;&#xA;" OwnerUserId="7655" LastEditorUserId="725" LastEditDate="2017-03-07T01:10:54.697" LastActivityDate="2022-07-21T22:09:37.773" Title="How was it possible that CO2 levels were higher nearly 650,000 years ago?" Tags="|climate-change|co2|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9836" PostTypeId="2" ParentId="9835" CreationDate="2017-03-06T20:52:29.283" Score="5" Body="&lt;p&gt;The explanation is that human activities are not the only processes that affect atmospheric composition.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Last time CO2 levels were higher than today was 10-15 million years, during the Miocene epoch. During the Miocene, sea level estimated to be 100 feet higher and the global average surface temperature estimated to be 10°F warmer than today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6ofFH.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6ofFH.jpg&quot; alt=&quot;Sea Level Change over time&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qA2Ly.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qA2Ly.png&quot; alt=&quot;Temperature over time&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.e-education.psu.edu/earth107/node/901&quot; rel=&quot;noreferrer&quot;&gt;Miocene Sea level graph.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.climateemergencyinstitute.com/climate_history.html&quot; rel=&quot;noreferrer&quot;&gt;Temperature over time graph.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.climatecentral.org/news/the-last-time-co2-was-this-high-humans-didnt-exist-15938&quot; rel=&quot;noreferrer&quot;&gt;www.climatecentral.org&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://science.sciencemag.org/content/326/5958/1394&quot; rel=&quot;noreferrer&quot;&gt;Coupling of CO2 and Ice Sheet Stability Over Major Climate Transitions of the Last 20 Million Years&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="1149" LastEditDate="2017-03-06T21:11:20.813" LastActivityDate="2017-03-06T21:11:20.813" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9838" PostTypeId="1" CreationDate="2017-03-07T02:19:53.623" Score="1" ViewCount="40" Body="&lt;p&gt;what caused the bend that formed in the emperor seamount chain. I've been looking around on websites but i cant seem to find a simple explanation.&lt;/p&gt;&#xA;" OwnerUserId="7658" LastActivityDate="2017-03-07T02:19:53.623" Title="What caused the bend in the Emperor/Hawaii chain islands?" Tags="|oceanography|" AnswerCount="0" CommentCount="0" ClosedDate="2017-03-07T11:48:47.280" ContentLicense="CC BY-SA 3.0" />
  <row Id="9842" PostTypeId="2" ParentId="9244" CreationDate="2017-03-07T03:59:42.653" Score="3" Body="&lt;p&gt;I believe that &lt;a href=&quot;http://www.leapfrog3d.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;Leapfrog 3D&lt;/a&gt; will do this. They have &lt;a href=&quot;http://www.leapfrog3d.com/academic&quot; rel=&quot;nofollow noreferrer&quot;&gt;academic licenses&lt;/a&gt;. I also seem to recall that &lt;a href=&quot;http://www.intrepid-geophysics.com/ig/index.php?page=geomodeller&quot; rel=&quot;nofollow noreferrer&quot;&gt;Intrepid Geomodeller&lt;/a&gt; does what you are after. Both of these options are probably overkill though.   &lt;/p&gt;&#xA;" OwnerUserId="777" LastActivityDate="2017-03-07T03:59:42.653" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9844" PostTypeId="1" AcceptedAnswerId="9845" CreationDate="2017-03-07T03:47:11.057" Score="8" ViewCount="4552" Body="&lt;p&gt;I'm quite confused about this since it is said to influence major currents in the sea the winds to the formation of gyres in the ocean and as well as influencing the weather at times due to the planet's rotation and the direction of where the winds are going.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any effects(positive/negative such as sudden algal blooms) generated by the Coriolis effect that can affect the rivers and the inhabitants near it?&lt;/p&gt;&#xA;" OwnerUserId="7661" OwnerDisplayName="Stavious" LastEditorUserId="111" LastEditDate="2017-05-17T16:54:38.070" LastActivityDate="2017-05-29T19:03:51.980" Title="How does the Coriolis effect affect rivers and estuaries" Tags="|rivers|ecology|coriolis|estuary|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9845" PostTypeId="2" ParentId="9844" CreationDate="2017-03-07T15:31:51.883" Score="5" Body="&lt;p&gt;The effects of Coriolis in rivers and estuaries are more subtle than in the open ocean. Coriolis tends to be a second or third order process in fast-moving and relatively small systems like rivers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, when the residual flow in an estuary is considered, then that process tends to be slow and persistent and the effects of Earth's rotation (Coriolis) can be more obvious. The residual flows tend to be much weaker than tidal flows in estuaries. Both seaward and landward residual flows are going to be slightly displaced to the right of the direction of flow (in the northern Hemisphere) resulting in asymmetric flows. The resulting exchange flow (in the northern Hemisphere), looking in up-estuary direction, is going to have denser seawater flowing into the estuary in the deeper right side of the estuary, while fresher (lighter) river water will tend to flow seaward near the surface along the left side of the estuary. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6m9ZV.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6m9ZV.jpg&quot; alt=&quot;exchange flow under Coriolis&quot;&gt;&lt;/a&gt; Source &lt;a href=&quot;http://www.po.gso.uri.edu/~codiga/foster/estuarine.htm&quot; rel=&quot;noreferrer&quot;&gt;GSO-URI&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The asymmetric flow exchange will affect any particle in suspension (e.g., organisms, sediment). In general, estuarine circulation tends to create areas of high turbidity (&lt;a href=&quot;https://faculty.washington.edu/pmacc/Classes/Est2011/lectures/Lecture_ETM_phys.ppt&quot; rel=&quot;noreferrer&quot;&gt;estuarine turbidity maximum&lt;/a&gt;, ETM) in the vicinity of the tip of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Estuary#Salt_wedge&quot; rel=&quot;noreferrer&quot;&gt;salt wedge&lt;/a&gt;. Decomposition of organic material in the high turbidity zone of the ETM can cause oxygen depletion, especially in the lower part of the vertical where mixing with oxygen-rich surface water is inhibited by stratification. In a system where Coriolis is a relevant factor, the distribution of this anoxic conditions (the often called &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Dead_zone_(ecology)&quot; rel=&quot;noreferrer&quot;&gt;dead zone&lt;/a&gt;&quot;) is going to be displaced and can be more extensive in the right side of the estuary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/t79HM.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/t79HM.gif&quot; alt=&quot;Columbia River Estuarine Turbidity Maxima&quot;&gt;&lt;/a&gt; Source: &lt;a href=&quot;https://depts.washington.edu/cretmweb/whatis.html&quot; rel=&quot;noreferrer&quot;&gt;Columbia River Estuarine Turbidity Maxima&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good summary of the effects of rotation (Coriolis) in estuaries can be found in &lt;a href=&quot;http://www.essie.ufl.edu/~arnoldo/ftp/papers/ESCO_00208.pdf&quot; rel=&quot;noreferrer&quot;&gt;Valle-Levinson (2011)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;http://www.essie.ufl.edu/~arnoldo/ftp/papers/ESCO_00208.pdf&quot; rel=&quot;noreferrer&quot;&gt;Valle-Levinson A (2011)&lt;/a&gt;  Large Estuaries (Effects of Rotation). In: Wolanski E and McLusky DS (eds.) Treatise on Estuarine and Coastal Science, Vol 2, pp. 123–140. Waltham: Academic Press.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="111" LastActivityDate="2017-03-07T15:31:51.883" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9848" PostTypeId="1" CreationDate="2017-03-07T17:41:39.240" Score="8" ViewCount="186" Body="&lt;p&gt;How much water is transported (volume) as a wave travels into a sea cave?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The wave has a height of 1 m and a period of 12 seconds. The average water depth at the cave mouth it 5 m and the width is 15 m.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How do I calculate this? This is a real-world problem and if there is any other information needed for this problem I will happily collect it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This isn't a homework problem. This is a real cave and I assumed water is transported because it does pile up in the back of the cave until the wave is reflected and exits the cave in the opposite direction. Just as on beaches where waves push water up on to the beach and gravity pulls the water back to ocean creating the nearshore current. I understand that deep water waves have an almost circular orbit but due to Stokes drift a particle will be slightly displaced in the direction the swell is moving. In this cave we can assume the wave is well with in the shallow water wave criteria and almost at the critical depth in which the wave deformation is extreme and wave energy is about to be converted into turbulent kinetic energy as the wave breaks. The orbit therefore would be linear, as the wave moves in and out. The net change would be 0 m$^3$, but how much water flows in and then flows back out of the cave?&lt;/p&gt;&#xA;" OwnerUserId="7663" LastEditorUserId="192" LastEditDate="2017-03-09T23:12:55.243" LastActivityDate="2017-03-10T17:40:35.417" Title="How much water does a wave transport into a sea cave?" Tags="|ocean|oceanography|water|waves|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9849" PostTypeId="1" CreationDate="2017-03-07T19:26:52.080" Score="1" ViewCount="98" Body="&lt;p&gt;Today, there are some scientists and people that are working on projects that will reduce the production of CO2 levels and effects of climate change. I'm very confused on whether it is possible for there to be enough change such that climate change can reduce and soon come to a stable level?&lt;/p&gt;&#xA;" OwnerUserId="7655" LastEditorUserId="543" LastEditDate="2017-03-18T06:43:30.073" LastActivityDate="2017-03-18T06:43:30.073" Title="Is it possible that we can reduce climate change given our current actions?" Tags="|climate|climate-change|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9850" PostTypeId="1" CreationDate="2017-03-07T20:21:06.270" Score="1" ViewCount="39" Body="&lt;p&gt;This is a question about residence time for another planet with the following information below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When we arrive on the second habitable planet, we discover that it is also exactly like Earth, except that each year its volcanoes emit 1000 GtC, and its ocean precipitates 1000 GtC as calcium carbonate. The citizens of this planet had been burning fossil fuels, but after we teach them about the dangers of climate change, they decide to switch entirely to solar power. About how long does it take for their atmosphere to return to its pre-industrial equilibrium value?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Everything else about the planet is identical to earth unless otherwise specified.&lt;/p&gt;&#xA;" OwnerUserId="7666" LastActivityDate="2017-03-07T20:21:06.270" Title="Residence time for another planet" Tags="|homework|co2|" AnswerCount="0" CommentCount="2" ClosedDate="2017-03-13T17:56:37.630" ContentLicense="CC BY-SA 3.0" />
  <row Id="9851" PostTypeId="2" ParentId="9849" CreationDate="2017-03-07T20:32:04.997" Score="1" Body="&lt;p&gt;Our current actions are most definitely not enough to reduce the rate of climate change.  Yes, it is possible that someday we could do enough to start reversing the damage, but we aren't anywhere close to that reality given our social customs that constantly rely on combustion.  Definitely not anything &quot;soon&quot;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reality is that emissions still go up nearly every year.  This is largely because most of the world (especially China) is actively converting to &quot;western&quot; lifestyle, which uses a lot of resources per capita.  Also, it takes hundreds of years for CO2 to decrease in the atmosphere naturally.  So, while there are many efforts to reduce CO2 emissions, the amount of carbon in the atmosphere still goes up every year.  If we could somehow advance carbon sequestration methods to  the point where we can reduce both oceanic and atmospheric carbon, then we could theoretically get back to &quot;normal&quot;.  To truly make a change in the right direction, though, the industrialized world needs to stop relying on combustion as the dominant energy source.  See the &lt;a href=&quot;http://www.globalcarbonproject.org/carbonbudget/index.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.globalcarbonproject.org/carbonbudget/index.htm&lt;/a&gt; slides (excerpt below) for more information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Emissions from fossil fuel use and industry:&lt;/strong&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/wfpya.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wfpya.png&quot; alt=&quot;Emissions from fossil fuel use and industry&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;And here is the atmospheric concentration as measured at Mauna Loa:&lt;/strong&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/jNVb5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jNVb5.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2017-03-18T06:37:57.887" LastActivityDate="2017-03-18T06:37:57.887" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9853" PostTypeId="1" AcceptedAnswerId="10802" CreationDate="2017-03-08T01:11:34.453" Score="11" ViewCount="10266" Body="&lt;h3&gt;Boundaries of the question:&lt;/h3&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The question is about rivers where water flows in cold area of the earth. Whether it's because of the winter or it's simply cold all year long. Usually, the top layer of the river freeze and water underneath continue to flow freely.&lt;/li&gt;&#xA;&lt;li&gt;The question is about the temperature of the liquid water only. So, the temperature of the solid water is irrelevant to the question.&lt;/li&gt;&#xA;&lt;li&gt;This question is only about fresh water rivers only. So salty rivers are not part of the question.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h3&gt;The question itself:&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;What is the temperature of the flowing water in icy river?&lt;br&gt;&#xA;More precisely, does the temperature of the water drop below 0 °C?&lt;br&gt;&#xA;If it does, is this common?&#xA;If it doesn't, does it get close to it at all?&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Attempted research to find the answer :&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;I had in mind that the current allowed the water to stay liquid, but that might be wrong because there is no proof to it.&#xA;However, &lt;a href=&quot;https://earthscience.stackexchange.com/a/4361/7668&quot;&gt;this answer&lt;/a&gt; says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;For flowing water to freeze, the temperature would have to be&#xA;  exceptionally cold.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Which seems to agree that current &lt;a href=&quot;http://sciencequestionswithsurprisinganswers.org/2013/12/09/can-water-stay-liquid-below-zero-degrees-celsius/&quot; rel=&quot;noreferrer&quot;&gt;can lower the freezing point&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found a great document about the temperature of the water within lake, but didn't find any reliable answer for rivers.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT&lt;/strong&gt;&lt;br&gt;&#xA;I have come to believe that temperatures don't typically fall below 0 °C, based upon aggregating the following information...   &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/4359/7668&quot;&gt;Rivers freeze completely once the heat lost exceeds the rate of water&#xA;replacement&lt;/a&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://www.greatlandofalaska.com/reference/faq.html#freezesolid&quot; rel=&quot;noreferrer&quot;&gt;Most lakes and rivers don't freeze solid because water,&#xA;ice, and snow are good insulators and poor conductors of heat. The&#xA;portions of a lake or river that is exposed to the cold winter air&#xA;freezes, and this ice insulates the water below from&#xA;further rapid freezing.&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Earth is warming the water from below. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Using this, we can probably conclude that water won't cool down enough during it's journey down the river. Thus, the water would need to be already colder at the start of the journey. We know that the start is a lake with calm water. So, it's unlikely to happen because the lake would freeze completely and stop flowing out into the river. &lt;/p&gt;&#xA;" OwnerUserId="7668" LastEditorUserId="7668" LastEditDate="2017-04-28T17:12:17.547" LastActivityDate="2017-07-12T06:09:54.917" Title="What is the temperature of the flowing water in icy river?" Tags="|temperature|water|rivers|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9855" PostTypeId="1" CreationDate="2017-03-08T02:40:33.367" Score="1" ViewCount="76" Body="&lt;p&gt;I'm looking for a algorithm or a formula to calculate the ecological footprint of one person who is using any kind of vehicle (car, public transit...).&lt;/p&gt;&#xA;" OwnerUserId="7670" LastEditorUserId="7670" LastEditDate="2017-03-08T12:39:38.853" LastActivityDate="2017-03-08T12:39:38.853" Title="How to calculate the Ecological footprint" Tags="|environmental-protection|carbon|" AnswerCount="0" CommentCount="1" ClosedDate="2017-03-09T09:02:51.847" ContentLicense="CC BY-SA 3.0" />
  <row Id="9857" PostTypeId="1" CreationDate="2017-03-08T06:37:42.443" Score="11" ViewCount="6363" Body="&lt;p&gt;Earth's atmosphere is 0.038% carbon dioxide. Mars's atmosphere is 95.3% carbon dioxide. Venus's atmosphere is 96.5% carbon dioxide.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If Earth's climate is controlled by CO&lt;sub&gt;2&lt;/sub&gt;, then why is Mars so cold in comparison to Venus? Mars is very cold (average about &amp;ndash;60&amp;deg;C) and Venus is very hot (+460&amp;deg;C). &lt;/p&gt;&#xA;" OwnerUserId="1034" LastEditorUserId="28050" LastEditDate="2018-01-06T14:15:50.457" LastActivityDate="2022-12-19T20:01:12.287" Title="Carbon dioxide on Mars, Venus and Earth" Tags="|climate-change|planetary-science|co2|mars|" AnswerCount="5" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9858" PostTypeId="2" ParentId="9857" CreationDate="2017-03-08T07:56:27.837" Score="10" Body="&lt;p&gt;Firstly, Mars is farther away from the sun than Venus or Earth, so it gets less heat from the sun. Secondly, Venus &amp;amp; Earth are volcanically active, whereas Mars is volcanically inert. Thirdly, the atmosphere on Mars is much thinner than those on Venus and Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The density of the atmosphere on &lt;a href=&quot;https://nssdc.gsfc.nasa.gov/planetary/factsheet/venusfact.html&quot; rel=&quot;noreferrer&quot;&gt;Venus&lt;/a&gt; is approximately $65\ \mathrm{kg/m}^3$, whereas, the density of &lt;a href=&quot;https://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html&quot; rel=&quot;noreferrer&quot;&gt;Earth's&lt;/a&gt; atmosphere is $1.217\ \mathrm{kg/m}^3$ and the density of &lt;a href=&quot;https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html&quot; rel=&quot;noreferrer&quot;&gt;Mars's&lt;/a&gt; atmosphere is $0.02\ \mathrm{kg/m}^3$. Earth's atmosphere is 60 times denser than that of Mars; Venus's atmosphere is over 3000 times denser.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With such a thin atmosphere on Mars, there is little atmospheric mass to retain heat, despite the atmosphere being composed of 95.3 percent carbon dioxide.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="28050" LastEditDate="2018-01-06T14:22:16.903" LastActivityDate="2018-01-06T14:22:16.903" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9859" PostTypeId="2" ParentId="9857" CreationDate="2017-03-08T13:48:30.293" Score="2" Body="&lt;p&gt;In addition to what has been said by @Fred, I'd like to add that CO2 doesn't actually generate heat, it is just very good at trapping heat. Mars doesn't get as much heat as Earth, and it also doesn't have enough CO2 to effectively trap heat that has been received, as a result, it's much colder than Earth. &lt;/p&gt;&#xA;" OwnerUserId="5077" LastActivityDate="2017-03-08T13:48:30.293" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9861" PostTypeId="1" CreationDate="2017-03-08T16:02:24.317" Score="3" ViewCount="216" Body="&lt;p&gt;How can oil can escape from a shale source rock into a reservoir rock if the shale itself is impermeable?&lt;/p&gt;&#xA;" OwnerUserId="7538" LastEditorUserId="2470" LastEditDate="2017-03-09T07:25:06.373" LastActivityDate="2017-03-09T12:16:01.740" Title="How can oil can escape from a shale source rock into a reservoir rock?" Tags="|geology|structural-geology|gas|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9863" PostTypeId="1" CreationDate="2017-03-08T19:12:21.417" Score="4" ViewCount="122" Body="&lt;p&gt;Have there been any air quality modeling studies regarding the locations where ozone is considered &quot;NOx limited&quot; (increasing NOx increases ozone)  or &quot;NOx sensitive&quot; (decreasing NOx increases ozone)? The larger the domain of the study, the better.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-03-08T19:12:21.417" Title="What geographical areas are NOx sensitive/limited (with regard to ozone)?" Tags="|atmospheric-chemistry|ozone|air-quality|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9864" PostTypeId="2" ParentId="8561" CreationDate="2017-03-08T19:29:07.717" Score="1" Body="&lt;p&gt;While the prospects are more of an economic question, I can answer that there is at least one study using machine learning methods (&lt;a href=&quot;https://etda.libraries.psu.edu/catalog/13561nvb5011&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://etda.libraries.psu.edu/catalog/13561nvb5011&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are problems such as the attribution of error to physical processes are not feasible, the spatial extent of the model is very limited, the accuracy of the model is dependent on the history and integrity of the data, etc. Perhaps a hybrid, some sort of Model Output Statistics could be formed, but this would be doubly expensive.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-03-08T19:29:07.717" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9865" PostTypeId="2" ParentId="246" CreationDate="2017-03-08T19:50:17.893" Score="-2" Body="&lt;p&gt;Nuclear reactions would be required to create a shaft. High melting point solids under the extreme pressures would be required to reinforce it.  If gamma rays can tunnel, the theory is not implausible but requires an engineering feet to put physics into practice. This should be the focus of exploration besides space exploration.&lt;/p&gt;&#xA;" OwnerUserId="7676" LastActivityDate="2017-03-08T19:50:17.893" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9866" PostTypeId="2" ParentId="9849" CreationDate="2017-03-08T21:49:09.150" Score="0" Body="&lt;p&gt;Is it possible for there to be enough change such that climate change can reduce and soon come to a stable level?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, sort of. For some value of &quot;soon&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of all the emissions released to date, it will take another thirty years for the first stage of impacts to make itself felt. So even if we went to net zero emissions tomorrow, we've got decades of seeing the first stage of impacts, and then centuries of seeing further consequences. (of course, the global climate will continue to change at the scale of tens of thousands of years, but I've understood your question to refer to human impacts, and human lifetimes)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But we're not close to getting to net zero emissions. We may be close to the time when emissions stop rising. Then they've got to level off, and then fall to zero. And then probably we'll want them to be deeply negative for a while, to prevent further damage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So we have decades of future climate change already built into the system. And the longer we take to get to net zero emissions, the longer it will be before things stabilise at human timescales. And the higher the cumulative emissions before we reach peak atmospheric CO2 concentrations, the worse the consequences for humankind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the political will was there, we could probably get to net negative emissions within 20 years. So, we could get to some kind of stability in, say 40-50 years.&lt;/p&gt;&#xA;" OwnerUserId="100" LastActivityDate="2017-03-08T21:49:09.150" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9867" PostTypeId="1" CreationDate="2017-03-08T22:58:21.127" Score="8" ViewCount="3008" Body="&lt;p&gt;I wanted to know what math is needed for hydrology, in particular surface water hydrology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In my research online, of Master's programs (either in Hydrology or Environmental Science with a concentration in Hydrology), the undergraduate math pre-requisites differ greatly from program to program: some just required a year of calculus, others wanted or strongly recommended Calculus I, II, and III and yet other programs it was Calculus I, II, III, Linear Algebra, and Differential equations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone have any suggestions or thoughts about how much math?!&lt;/p&gt;&#xA;" OwnerDisplayName="user7678" LastEditorUserId="10681" LastEditDate="2018-09-13T11:28:01.383" LastActivityDate="2018-09-15T19:05:08.830" Title="Math needed for Hydrology, specifically surface water hydrology" Tags="|geology|hydrology|mathematics|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="9868" PostTypeId="1" AcceptedAnswerId="9875" CreationDate="2017-03-09T09:28:24.337" Score="5" ViewCount="3079" Body="&lt;p&gt;Is it possible to convert Air vapor pressure ($N/m^2$) to relative humidity (%) given a known air temperature? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, I know that relative humidity can be estimated as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ RH = 100* \frac{e_{a}}{e_{s}}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $e_{a}$ is the air vapor pressure and $e_{s}$ saturated vapor pressure at air temperature, both with units of mb. Specifically, $e_{s}$ can be estimated by:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$e_{s} = 6.11*\exp\left(\frac{17.27T_{a}}{237.3+T_{a}}\right)$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $T_{a}$ is the air temperature in $^{o}C$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, in my case the air vapor pressure has units of $N/m^2$? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can I use this conversion with these values/units? Is it simply the case of converting $e_{a}$ to mb via:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$e_{a} (mb) = e_{a} (N/m^{2})*0.01$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and then using the equation?&lt;/p&gt;&#xA;" OwnerUserId="4582" LastEditorUserId="2470" LastEditDate="2017-03-09T11:37:14.550" LastActivityDate="2017-03-10T07:52:10.313" Title="Convert air vapor pressure to relative humidity" Tags="|meteorology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9869" PostTypeId="2" ParentId="9861" CreationDate="2017-03-09T12:05:40.293" Score="1" Body="&lt;p&gt;Shale typically has a low permeability but shale is not technically impermeable.&#xA;Natural occurring faults, fractures and joints in shale can greatly increase the permeability of the rock.  This is why hydraulic fracturing (or fracking) is used to increase fluid flow (for both water, natural gas and petroleum wells) in host rock with low permeability.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fractured shale can allow a significant amount of fluid because some shale can have porosity values greater than 10%.  Given the grain size of shale, this can be a significant amount of space available to hold fluids.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.nap.edu/read/2309/chapter/4&quot; rel=&quot;nofollow noreferrer&quot;&gt;Physical Characteristics of Fractures and Fracture Patterns&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.spec2000.net/22-fracloc1.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;FRACTURED RESERVOIR BASICS&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Hydraulic_fracturing&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hydraulic Fracturing&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://www.geomore.com/porosity-and-permeability-2/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Shale porosity&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="1149" LastEditDate="2017-03-09T12:16:01.740" LastActivityDate="2017-03-09T12:16:01.740" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9870" PostTypeId="1" AcceptedAnswerId="9871" CreationDate="2017-03-09T12:57:46.903" Score="7" ViewCount="7595" Body="&lt;p&gt;I got caught in a downpour while climbing a mountain and was amazed to see, as I climbed down, the tiny trickles of water combine to form mini-streams, the dry rocks I had climbed up now hosted sizable waterfalls, and the path which I had followed to the mountain had become a small river.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But it got me wondering about my question, which  is the reverse of this. Why, after a long period of dry weather, are many rivers still flowing? I live near a river and it seems that it takes over a week of dry weather before there's any noticeable drop in its level. How does it not simply run out of water? &#xA;Is it simply that it takes very a long time for the water at its source and the sources of all its tributaries to reach the point I'm observing from?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems there's a constant supply of water when I would have expected the network of rivers to start draining, and the drying up starting from the source the moment the rain stopped.&lt;/p&gt;&#xA;" OwnerUserId="7682" LastActivityDate="2020-05-20T10:31:39.093" Title="How do rivers last so long in dry weather?" Tags="|geography|rivers|rainfall|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9871" PostTypeId="2" ParentId="9870" CreationDate="2017-03-09T14:21:05.487" Score="11" Body="&lt;p&gt;The rivers are generally fed by water that percolated into the ground, it takes longer for that water to work its way down to the stream so the streams and rivers keep flowing long after the initial rain. &lt;a href=&quot;https://water.usgs.gov/edu/rivers-contain-groundwater.html&quot; rel=&quot;noreferrer&quot;&gt;https://water.usgs.gov/edu/rivers-contain-groundwater.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2017-03-09T14:21:05.487" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9872" PostTypeId="2" ParentId="9870" CreationDate="2017-03-09T15:04:19.720" Score="5" Body="&lt;p&gt;A river's primary of source of water is precipitation, surface water run off, and shallow groundwater discharge within the drainage basin the river is located.  The size of the drainage basin really determines if a river may run dry during drought conditions. Some river basins are so large that drought conditions are unlikely to persist over the entire basin at any given moment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(See &lt;a href=&quot;http://www.mvn.usace.army.mil/Missions/Mississippi-River-Flood-Control/Mississippi-River-Tributaries/Mississippi-Drainage-Basin/&quot; rel=&quot;noreferrer&quot;&gt;image&lt;/a&gt; drainage showing Mississippi River drainage ~1/2 of the US).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3devA.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3devA.jpg&quot; alt=&quot;Mississippi River Drainage basin.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/twYeN.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/twYeN.jpg&quot; alt=&quot;Colorado River Drainage basin&quot;&gt;&lt;/a&gt; &lt;a href=&quot;http://www.waterencyclopedia.com/Ce-Cr/Colorado-River-Basin.html&quot; rel=&quot;noreferrer&quot;&gt;Reference&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With the Colorado river, scarce rainfall and over-usage leads to a greatly diminished flow at discharge into the into the Gulf of California (Sea of Cortez).&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-03-09T15:04:19.720" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9873" PostTypeId="2" ParentId="9870" CreationDate="2017-03-09T17:02:19.813" Score="2" Body="&lt;p&gt;Glaciars and snow in mountains act as natural dams for many rivers. That's why several rivers have an increase of their flow during hot times, when the snow melts and the river moves more water compared to other times of the year.&lt;br&gt;&#xA;Since many mountains keep part of their snow and glaciars the whole year, the rivers that start there will have water for a long time.&lt;br&gt;&#xA;Finally, snow that falls in mountains is by far more than the rain that falls in the valley below, so each rain you see in the valley is a storm up in the mountains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In exchange, rivers that depends heavily on rainfall are more prone to dry once the rain stops.&lt;/p&gt;&#xA;" OwnerUserId="5004" LastActivityDate="2017-03-09T17:02:19.813" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9874" PostTypeId="1" AcceptedAnswerId="24505" CreationDate="2017-03-09T19:01:52.310" Score="0" ViewCount="90" Body="&lt;p&gt;Beginning with the Primitive equations governing atmospheric motion for a dry gas, primarily the ideal gas law, and the conservation of mass and energy, neglecting diffusivity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$P=\rho R T$$ &#xA;$$\omega \equiv \frac{DP}{Dt}$$&#xA;Therefore&#xA;$$\omega=R(\rho\frac{DT}{Dt}+T\frac{D\rho}{Dt})$$&#xA;Since $$\frac{D\rho}{Dt}=-\rho \nabla\cdot\vec{u}$$ and $$\frac{DT}{Dt}=\frac{\omega\rho}{c_p}+\frac{Q}{c_p}$$&#xA;$$\omega=R(\frac{\rho^2\omega}{c_p}+\frac{\rho Q}{c_p}-T\rho\nabla\cdot\vec{u})$$&#xA;Distributing $R$ and applying the ideal gas law $$\omega=\frac{R\rho^2\omega}{c_p}+\frac{PQ}{Tc_p}-P\nabla\cdot\vec{u}$$&#xA;Separating $\omega$ from the right hand side of the equation yields&#xA;$$\omega=(1-\frac{R\rho^2}{c_p})^{-1}(\frac{PQ}{Tc_p}-P\nabla\cdot\vec{u})$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I call this semi-diagnostic, for $\omega$ is still a part of $\nabla\cdot\vec{u}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this a valid semi-diagnostic equation for $\omega$?&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2022-11-13T13:19:48.457" Title="Is this a valid semi-diagnostic equation for Omega?" Tags="|thermodynamics|dynamics|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="9875" PostTypeId="2" ParentId="9868" CreationDate="2017-03-09T22:13:17.777" Score="2" Body="&lt;p&gt;$$1\:\mathrm{N/m^2} = 1 \:\mathrm{Pa}$$&#xA;$$100 \:\mathrm{Pa} = 1 \:\mathrm{hPa} = 1 \:\mathrm{mb}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So yes, you do have valid units of pressure.  And can easily convert it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The calculation $ RH = 100* \frac{e_{a}}{e_{s}}$ will work as long as the pressures are in equal units, whether Pa, mb, Gbar, etc, since it's just a ratio.  They just need to be the same.  So, you can convert your given $e_a$ into mb by multiplying by 100, convert your $e_s$ into Pa by dividing by 100, or just apply the change in the $e_s$ equation to get $e_s$ in $\:\mathrm{N/m^2}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We often use your $e_s=6.11∗exp(17.27T_a/(237.3+T_a))$ in meteorology since we work with pressures in mb (or equivalently hPa).  But indeed the same equation simply works with the constant adjusted to the proper units as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$e_{s} = 0.0611*\exp\left(\frac{17.27T_{a}}{237.3+T_{a}}\right)$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;giving answers in Pascals ( = $\:\mathrm{N/m^2}$).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So long story short: &lt;strong&gt;yes, all of your equations and reasoning are good, your units are all pressures, they just don't match form.  But you can indeed adjust at any step to account for that.  Simplest is multiplying your $e_a$ (in $\mathrm{N/m^2}$) by 100 or dividing your $e_s$ (in $\mathrm{ mbar}$) by 100 to make them match.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also of note, the first equation you gave is exactly valid.  The second equation, as you indicate, is an estimation.  The longer version described in &lt;a href=&quot;http://www.vaisala.com/Vaisala%20Documents/Application%20notes/Humidity_Conversion_Formulas_B210973EN-F.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt; would give exact values if you wish, but it looks like you're unlikely to be off by more than 0.1%, so what you're doing is likely fine unless you're need very exacting precision.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-03-10T07:52:10.313" LastActivityDate="2017-03-10T07:52:10.313" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9876" PostTypeId="2" ParentId="9848" CreationDate="2017-03-09T23:10:23.907" Score="4" Body="&lt;p&gt;The time-averaged material transport by water waves is quantified by Stokes drift, which is the residual Lagrangian drift due to sub-surface orbits not being closed:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;u_{St} = \dfrac{\omega k^2 a \cosh[2k(z+d)]}{2\sinh(kd)^2}&#xA;$$&#xA;where $\omega$ is the angular frequency, $k$ is the wavenumber, $a$ is the wave amplitude, $d$ is mean water depth, and $z$ is the displacement from water surface, positive upward.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because the cave is closed, there is build-up of water in the cave which results in pressure gradient-induced Eulerian backflow which opposes the Stokes drift. This backflow is barotropic in nature and equals:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;u_E = -\dfrac{1}{d}\int_{-d}^{0}u_{St}(z)dz&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The transport velocity is the sum of mean Eulerian velocity and Stokes drift:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;u_L = u_E + u_{St}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the case of $T = 12\ s$, $a = 1\ m$, and $d = 5\ m$, the resulting transport looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qwDrD.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qwDrD.png&quot; alt=&quot;wave transport&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because the Stokes drift is not uniform in the vertical but compensating Eulerian backflow is, the resulting transport is into the cave in the upper 2 m, and out of the cave below that depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assumptions made:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Inviscid ($\mu\nabla^2\mathbf{u}=0$), irrotational ($\nabla \times \mathbf{u} = 0$), and incompressible ($\nabla\cdot \mathbf{u}=0$) flow.&lt;/li&gt;&#xA;&lt;li&gt;Small amplitude for the linear wave theory to hold.&lt;/li&gt;&#xA;&lt;li&gt;All wave energy is dissipated at the cave wall (no reflection). If there is some reflection of waves out of the cave, then the Stokes drift and the corresponding Eulerian backflow would be reduced in magnitude, but the answer for the net transport would be qualitatively the same.&lt;/li&gt;&#xA;&lt;li&gt;Shallow water dispersion relationship ($\omega^2 = gk^2d$).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;And here is the Python code:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;import numpy as np&#xA;import matplotlib.pyplot as plt&#xA;&#xA;T = 12. # wave period [s]&#xA;d = 5.  # mean water depth [m]&#xA;a = 1.  # wave amplitude [m]&#xA;g = 9.8 # gravitational acceleration [m/s]&#xA;&#xA;omega = 2*np.pi/T # angular frequency [rad/s]&#xA;k = np.sqrt(omega**2/(g*d)) # wavenumber [rad/m]&#xA;&#xA;z = np.linspace(0,-d,501.) # depth array [m]&#xA;dz = -np.gradient(z) # depth increment [m]&#xA;&#xA;# Stokes drift in arbitrary depth&#xA;ust = 0.5*omega*k*a**2*np.cosh(2*k*(z+d))/np.sinh(k*d)**2&#xA;&#xA;# Eulerian backflow is the vertical integral of Stokes drift&#xA;ue = -np.ones(z.size)*np.sum(ust*dz)/d&#xA;&#xA;fig = plt.figure(figsize=(8,6))&#xA;ax = fig.add_subplot(111,xlim=(-0.2,0.2),ylim=(5,0))&#xA;ax.tick_params(axis='both',which='major',labelsize=16)&#xA;plt.plot(ust,-z,'r-',lw=3,label='Stokes drift')&#xA;plt.plot(ue,-z,'g-',lw=3,label='Eulerian backflow')&#xA;plt.plot(ust+ue,-z,'k-',lw=3,label='Lagrangian velocity')&#xA;plt.plot([0,0],[5,0],'k--')&#xA;plt.legend(loc='lower left',shadow=True,fancybox=True)&#xA;plt.grid(True)&#xA;plt.xlabel('Velocity [m/s]',fontsize=16)&#xA;plt.ylabel('Depth [m]',fontsize=16)&#xA;plt.savefig('transport.png',dpi=100)&#xA;plt.close(fig)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="192" LastEditorUserId="192" LastEditDate="2017-03-10T17:40:35.417" LastActivityDate="2017-03-10T17:40:35.417" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9878" PostTypeId="1" CreationDate="2017-03-10T06:04:00.987" Score="0" ViewCount="2201" Body="&lt;p&gt;I'm living at place &lt;strong&gt;A&lt;/strong&gt; I traveled to &lt;strong&gt;B&lt;/strong&gt; and I seen like sun isn't set as in place &lt;strong&gt;A&lt;/strong&gt;. Like directions are changed. Where &lt;strong&gt;east&lt;/strong&gt; is in place &lt;strong&gt;B&lt;/strong&gt; is &lt;strong&gt;north&lt;/strong&gt; of &lt;strong&gt;A&lt;/strong&gt; and &lt;strong&gt;south&lt;/strong&gt; of &lt;strong&gt;A&lt;/strong&gt; is   &lt;strong&gt;west&lt;/strong&gt; of &lt;strong&gt;B&lt;/strong&gt;. Because of sun wasn't set in &lt;strong&gt;B&lt;/strong&gt; as usually as set in place &lt;strong&gt;A&lt;/strong&gt;. Sun rises in north at place &lt;strong&gt;B&lt;/strong&gt; and sets in south. I really confused with this phenomenon of nature. Is it mean we consider direction which region we living in? Is it all because of &lt;i&gt;longitude&lt;/i&gt; and &lt;i&gt;latitude&lt;/i&gt;? Why it'd be like this? May it because if sun travel by specific longitude and latitude and so we would confused in situation like this even sun is stable planet and just earth rotate?&lt;/p&gt;&#xA;" OwnerUserId="7687" LastEditorUserId="7687" LastEditDate="2017-03-10T08:46:05.187" LastActivityDate="2017-03-10T12:26:07.163" Title="Why in different places seems directions are changed?" Tags="|earth-rotation|earth-system|" AnswerCount="1" CommentCount="11" ClosedDate="2017-03-10T13:14:53.593" ContentLicense="CC BY-SA 3.0" />
  <row Id="9879" PostTypeId="1" CreationDate="2017-03-10T12:12:12.210" Score="4" ViewCount="81" Body="&lt;p&gt;Where can I find free information to learn if the forecasted ENSO El Nino event for 2nd semester 2017 will be a MODOKI one?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Japan Meteo Service also publishes the EL-NINO-MODOKI Index (below), but:&#xA; - what are the chances/probability that we are going through JULY and AUGUST under a Modoki El Niño ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ACSdE.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ACSdE.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7689" LastEditorUserId="4784" LastEditDate="2017-03-10T23:26:28.523" LastActivityDate="2017-03-10T23:26:28.523" Title="Will the next ENSO event be of modoki type?" Tags="|meteorology|climate|enso|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9880" PostTypeId="2" ParentId="9878" CreationDate="2017-03-10T12:26:07.163" Score="1" Body="&lt;p&gt;Even though sun always moves from east to west, latitude affects the north-south perception.&lt;br&gt;&#xA;If you are in the north hemisphere, beyond the tropic of cancer, the sun will be most of the time in the south hemisphere (except close to dawn and dusk, where it might cross to the other hemisphere during summer). While if you're in the south hemisphere, beyond the tropic of capricorn, the sun will be at north.&lt;br&gt;&#xA;Usually I use the sun to check where is the north in a map, but I must remember the north-south rule, otherwise I might choose the wrong direction to follow... that's why a bougth a cheap compass.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since you're talking about two places that are in the tropical belt, most part of the year the sun will rise in the north-east, move later to the south and it will end in the north-west. But during the winter the sun probably will be always in the south hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Probably the difference they are seeing between two close towns is due to different times of the year or due to a mountain that covers the exact sunset in the horizon in one place.&lt;/p&gt;&#xA;" OwnerUserId="5004" LastActivityDate="2017-03-10T12:26:07.163" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9882" PostTypeId="1" AcceptedAnswerId="9883" CreationDate="2017-03-10T17:12:59.030" Score="6" ViewCount="312" Body="&lt;p&gt;A barotropic fluid is a fluid whose density is a function of pressure only, i.e. $\rho=\rho(p)$. My understanding is that, in the atmosphere, in general, the tropics are barotropic whereas the extratropics are baroclinic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the atmosphere is an ideal gas, then $\rho =p/R T$. Therefore, density is a function of pressure &lt;em&gt;and&lt;/em&gt; temperature. How, then, can the atmosphere ever be barotropic?&lt;/p&gt;&#xA;" OwnerUserId="7690" LastActivityDate="2017-03-10T17:50:06.883" Title="If the atmosphere is (very nearly) an ideal gas, how can it ever be barotropic?" Tags="|meteorology|atmosphere|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9883" PostTypeId="2" ParentId="9882" CreationDate="2017-03-10T17:50:06.883" Score="3" Body="&lt;p&gt;You are correct, the atmosphere cannot ever be barotropic. It is important to note that the ideal gas law is relevant only as a state equation; it does not describe the gas as a whole. The barotropic assumption effectively states $P=\rho RT_0$. Effectively, it says &quot;hold temperature constant&quot; You may note this is particularly important when discussing the hydrostatic and hypsometric/barometric equations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On that note, the atmosphere is never entirely barotropic; the atmosphere cannot undergo entirely adiabatic motions; the wind can never stay geostrophic, etc. There are assumptions that are bad, and we know they are (take a class in micrometeorology dealing with similarity theory). But in the words of George Box, &quot;All models are wrong, but some are useful.&quot; These simple models teach us about basic atmospheric behavior.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is also worth noting that the ideal gas law is not the only equation of state. The Boussinesq and anelastic approximations can lead to interesting other formulations of the equation of state.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-03-10T17:50:06.883" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9884" PostTypeId="1" AcceptedAnswerId="9885" CreationDate="2017-03-11T05:14:12.303" Score="3" ViewCount="149" Body="&lt;p&gt;Is there any case that changed from earthquake safe zone to danger zone? As plates move, I think that earthquakes belt will change over time. But is there really a case in which the earthquake-safe zone was replaced by an earthquake-prone region for such a shift or for any other reason?&#xA; Or is there a region that is predicted to be an earthquake hazard zone in the future?&lt;/p&gt;&#xA;" OwnerUserId="7691" LastEditorUserId="1149" LastEditDate="2017-03-11T20:57:20.613" LastActivityDate="2017-03-11T21:05:24.560" Title="Is there any case that changed from earthquake safe zone to danger zone?" Tags="|geology|geophysics|earthquakes|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9885" PostTypeId="2" ParentId="9884" CreationDate="2017-03-11T13:38:09.060" Score="4" Body="&lt;p&gt;Yes, prior to 1983, central Idaho was classified low to moderate.  On October 28, 1983,  a  powerful earthquake occurred in Lost River Range at Borah Peak in central Idaho. The shock measured 6.9 on the moment magnitude scale and had a maximum Mercalli intensity of IX (Violent).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The earthquake was centered only 50 miles from a Idaho National Engineering Lab (nuclear research laboratory), but no damage was reported a the site. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, I can't find an internet accessible report but I remember discussing this earthquake at length in a Engineering Geology class I was taking in 1986.  The magnitude of the Borah Peak surprised the US government prompted the USGS to reclassify earthquake hazard zones in Idaho and Utah.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Location of Borah Peak, Idaho.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/VTIfg.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VTIfg.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Current quake hazard map (from &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/byregion/idaho-haz.php&quot; rel=&quot;noreferrer&quot;&gt;USGS&lt;/a&gt;:) &#xA;&lt;a href=&quot;https://i.stack.imgur.com/VTIfg.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/evE8V.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/1983_Borah_Peak_earthquake&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia Borah Peak.&lt;/a&gt; &lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.nytimes.com/1983/10/29/us/two-children-die-as-quake-hits-northwest-and-canada.html&quot; rel=&quot;noreferrer&quot;&gt;New York Times article on quake&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://imnh.isu.edu/digitalatlas/geo/quakes/borahEQ/boraheq.htm&quot; rel=&quot;noreferrer&quot;&gt;Geological summary of the quake: Idaho State University By, Steven W. Moore, Geologist and R. David Hovland, Geologist:&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-03-11T13:38:09.060" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9886" PostTypeId="1" CreationDate="2017-03-11T18:28:13.173" Score="5" ViewCount="517" Body="&lt;p&gt;Is a &lt;em&gt;show&lt;/em&gt; when naturally ocurring oil seeps out of a fracture on the surface? Or is it when engineers fracture rocks in order to extract oil?&lt;/p&gt;&#xA;" OwnerUserId="7538" LastEditorUserId="2536" LastEditDate="2017-03-12T21:17:05.833" LastActivityDate="2017-03-12T21:17:05.833" Title="What is a &quot;show&quot; in petroleum geology?" Tags="|geology|terminology|petroleum|gas|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9887" PostTypeId="2" ParentId="9884" CreationDate="2017-03-11T21:05:24.560" Score="1" Body="&lt;p&gt;Yes, for example, earthquakes have increased dramatically in Oklahoma since 2009 due to the effects of hydraulic fracking; this has sometimes been nicknamed the Oklahoma Earthquake Swarm.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Link for Oklahoma Area Seismicity from 1973-2016: &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/byregion/oklahoma/OKquakes1973_062642016v3.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earthquake.usgs.gov/earthquakes/byregion/oklahoma/OKquakes1973_062642016v3.pdf&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Link for USGS Hazard Estimation for induced earthquakes: &lt;a href=&quot;https://earthquake.usgs.gov/research/induced/hazards.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earthquake.usgs.gov/research/induced/hazards.php&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The first link provides a good view for how the history of earthquakes in Oklahoma. The second provides data of past and predicted hazards of induced earthquakes (earthquakes caused by human activity rather than natural plate movement) in the US.&lt;/p&gt;&#xA;" OwnerUserId="7307" LastActivityDate="2017-03-11T21:05:24.560" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9888" PostTypeId="2" ParentId="9886" CreationDate="2017-03-12T00:37:54.287" Score="4" Body="&lt;p&gt;A &lt;em&gt;show&lt;/em&gt; is a visual indication of hydrocarbons, in the jargon of petroleum exploration, it is typically used to describe a drilling. It could be e.g. a &lt;em&gt;Gas show&lt;/em&gt; in the drilling fluid. &lt;a href=&quot;http://wiki.aapg.org/Show_evaluation&quot; rel=&quot;noreferrer&quot;&gt;Show evaluation&lt;/a&gt; is an important tool to understand a reservoir. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When hydrocarbons reach the surface naturally, we call it a &lt;a href=&quot;https://en.wikipedia.org/wiki/Petroleum_seep&quot; rel=&quot;noreferrer&quot;&gt;petrolium seep&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Technically, I guess, a &lt;em&gt;seep&lt;/em&gt; could be a &lt;em&gt;show&lt;/em&gt; if it's used to map a &lt;a href=&quot;http://www.glossary.oilfield.slb.com/Terms/p/play.aspx&quot; rel=&quot;noreferrer&quot;&gt;play&lt;/a&gt; but I never heard the term used in that context. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastActivityDate="2017-03-12T00:37:54.287" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9890" PostTypeId="1" CreationDate="2017-03-12T11:35:43.747" Score="6" ViewCount="3789" Body="&lt;p&gt;In the film &lt;em&gt;Kong: Skull Island&lt;/em&gt;, scientists investigate an island's structure by dropping explosive charges from helicopters:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Py6dD.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Py6dD.gif&quot; alt=&quot;Kong: Skull Island clip&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;Source: &lt;a href=&quot;https://www.youtube.com/watch?v=AP0-9FBs2Rs&quot; rel=&quot;nofollow noreferrer&quot;&gt;YouTube trailer&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In reality, geophysicists do something similar using buried explosives.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sCNLr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sCNLr.jpg&quot; alt=&quot;Seismic charge detonation&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;Source: &lt;a href=&quot;http://www.fondasol.fr/en/services/geophysical-measurements.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;fondasol.fr&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In simple terms, how does detonating explosives in the ground help us to understand the subsurface structure?&lt;/p&gt;&#xA;" OwnerUserId="7504" LastEditorUserId="94" LastEditDate="2017-03-18T10:30:13.233" LastActivityDate="2017-03-19T14:00:56.610" Title="How do seismic charges help to investigate the subsurface?" Tags="|geophysics|seismology|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="9891" PostTypeId="1" AcceptedAnswerId="9898" CreationDate="2017-03-12T16:04:44.553" Score="6" ViewCount="1948" Body="&lt;p&gt;There is a requirement to measure BOD/COD in a wastewater treatment plant in real time. Is it possible? And if so are there any sensors available in the market for it?&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;COD: &lt;a href=&quot;https://en.wikipedia.org/wiki/Chemical_oxygen_demand&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chemical Oxygen Demand&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;BOD: &lt;a href=&quot;https://en.wikipedia.org/wiki/Biochemical_oxygen_demand&quot; rel=&quot;nofollow noreferrer&quot;&gt;Biochemical Oxygen Demand&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="7697" LastEditorUserId="6031" LastEditDate="2019-05-27T06:57:37.013" LastActivityDate="2019-08-07T22:20:56.037" Title="Can you measure BOD/COD real time using any sensor?" Tags="|geochemistry|remote-sensing|biogeochemistry|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="9892" PostTypeId="2" ParentId="5386" CreationDate="2017-03-12T20:24:28.717" Score="1" Body="&lt;p&gt;Did you try inpainting methods? Inpainting methods try to replace missing data using the existent data. I suggest you check the inpaint_nans.m function in fileexchange.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt; [x,y] = meshgrid(0:.01:1);&#xA; z0 = exp(x+y);&#xA; znan = z0;&#xA; znan(20:50,40:70) = NaN;&#xA; znan(30:90,5:10) = NaN;&#xA; znan(70:75,40:90) = NaN;&#xA;&#xA; z = inpaint_nans(znan);&#xA;&#xA;figure,imagesc(znan),axis image&#xA;figure,imagesc(z),axis image&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kvnpd.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kvnpd.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UIjV8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UIjV8.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7699" LastActivityDate="2017-03-12T20:24:28.717" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9893" PostTypeId="1" AcceptedAnswerId="9904" CreationDate="2017-03-12T23:30:24.107" Score="5" ViewCount="1441" Body="&lt;p&gt;I was watching &lt;a href=&quot;https://www.youtube.com/watch?v=t8b0JIPGyOA&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt; interview of Bill Nye on Fox News. Bill claimed that the earth's climate is never in equilibrium, but human activity has caused the gradient to be much higher than it would've been in the absence of humans. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does this mean that $\dfrac {\Delta\text{avg. global temperature}}{\text{year}}$ is higher than it should be? Is this even a sensible way to measure the impact of global warming? If so, what is the current number, and do we have an estimate of what the number would have been naturally in the absence of humans?&lt;/p&gt;&#xA;" OwnerUserId="6072" LastEditorUserId="6467" LastEditDate="2017-03-13T00:41:42.190" LastActivityDate="2017-04-17T00:42:11.403" Title="Rate of climate change with and without humans?" Tags="|climate|climate-change|human-influence|natural-conditions|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9894" PostTypeId="2" ParentId="7328" CreationDate="2017-03-13T05:22:28.237" Score="5" Body="&lt;p&gt;Try quiver3 function in Matlab. For example, this is the example in Matlab's website for this function:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7v79p.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7v79p.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7699" LastActivityDate="2017-03-13T05:22:28.237" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9897" PostTypeId="1" AcceptedAnswerId="9903" CreationDate="2017-03-13T15:51:32.603" Score="3" ViewCount="302" Body="&lt;p&gt;Water capacity decreases as the atmosphere cools.  However, a denser cold atmosphere sinks while a warm, lighter atmosphere rises.  Can one assume atmosphere (primarily nitrogen) is heavier than water (vapor)?  &lt;/p&gt;&#xA;" OwnerUserId="7705" LastActivityDate="2017-03-14T05:51:15.257" Title="Can one assume atmosphere (primarily nitrogen) is heavier than water (vapor)?" Tags="|meteorology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9898" PostTypeId="2" ParentId="9891" CreationDate="2017-03-13T16:56:12.877" Score="3" Body="&lt;p&gt;&lt;a href=&quot;http://realtechwater.com/municipal-sewage-monitoring/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Realtech.com&lt;/a&gt; has a runtime monitoring senser solution for BOD/COD Sensor.&#xA;My understanding is that COD is straight-ward to measure in real-time but BOD monitoring cannot be done in real-time.   The sensor listed uses a BOD equivalent monitoring technique.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The governing environmental regulatory agencies for a specific waste water facility should have public statement of acceptable BOD monitoring methods.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-03-13T16:56:12.877" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9899" PostTypeId="1" AcceptedAnswerId="9900" CreationDate="2017-03-13T17:24:27.197" Score="3" ViewCount="102" Body="&lt;p&gt;I want to test some 3D weather radar software by simulating rainy weather. I want some degree of realism in the sense that it simulates rain systems and their boundaries and also simulates rain rates over their volumes. Weather systems should be dynamic in the sense that they can evolve and change at typical rates. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would be satisfied with a statistical model if that's possible, rather than one driven by solving differential equations, based on my assumption that generating random numbers is easier than solving large systems of equations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The model should be capable of running for long periods of time (a few hours of simulated real time) while generating an assorted set of weather patterns (clear weather and various levels of rain intensity). It should be suitable for real time simulation of the radar software, so weather development over time is an important requirement. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Being able to support real-time simulation is another reason I am leaning toward any more simplistic (by arguably reasonable) model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know where to begin finding a model like this. The models I have seen appear to be more complex than I would like, and probably not really suitable for my limited requirement. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would help me is to identify any existing models that might be used for this purpose or any literature that describes how to create a model like this.&lt;/p&gt;&#xA;" OwnerUserId="2455" LastActivityDate="2017-03-13T17:34:35.080" Title="Simulating rainy weather" Tags="|meteorology|simulation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9900" PostTypeId="2" ParentId="9899" CreationDate="2017-03-13T17:34:35.080" Score="3" Body="&lt;p&gt;The problem with a statistical model is the reliance on dynamical model input, plus the requirement of climatology. A statistical model will also only give data for a solitary point, not an area. The simplest statistical model is persistence, which is the current weather, followed by climatology. Both are the lowest in forecast skill.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a dynamic model, try using the WRF model (&lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/download/get_source.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www2.mmm.ucar.edu/wrf/users/download/get_source.html&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is a commonly used model. The runtime will range, depending on your computational power and needs. A larger domain will take longer, and require more. I know people who simulate hurricanes with it, and people who run fine scale modeling.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can run WRF with a 200 km domain size for a 36 hour forecast in 1-2 hours.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Again it will really depend on your resources. Running WRF may require compilers you do not have access to. You can develop the visualization software after you ran the model, with whatever tools you find. Python and NCL are good languages, but MATLAB and a variety of other languages can be used.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-03-13T17:34:35.080" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9902" PostTypeId="1" CreationDate="2017-03-14T05:16:07.787" Score="4" ViewCount="233" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Hhbbg.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Hhbbg.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See this picture from the book &lt;a href=&quot;https://books.google.nl/books/about/Global_Physical_Climatology.html?id=RsScBAAAQBAJ&amp;amp;source=kp_cover&amp;amp;redir_esc=y&quot; rel=&quot;noreferrer&quot;&gt;Hartmann, Dennis L - Global Physical Climatology&lt;/a&gt;.&lt;br /&gt;&#xA;There is a minimum temperature point of 200K at 15km height above the  equator, in June/July/August.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know why this happens. Can anyone explain this?&lt;/p&gt;&#xA;" OwnerUserId="7692" LastEditorUserId="595" LastEditDate="2017-03-14T08:41:16.190" LastActivityDate="2017-03-14T13:22:44.093" Title="Minimum temperature on 15km height on equator in JJA?" Tags="|meteorology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9903" PostTypeId="2" ParentId="9897" CreationDate="2017-03-14T05:51:15.257" Score="2" Body="&lt;p&gt;Yes, humid air is less dense, but temperature and pressure are much bigger factors in the density of air.   Temperature and pressure are what drive updrafts and wind speed and direction much more than watervapor. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Humidity#Absolute_humidity&quot; rel=&quot;nofollow noreferrer&quot;&gt;Absolute Humidity&lt;/a&gt;, or, the mass of water vapor in air, is a smaller factor.  See &lt;a href=&quot;https://en.wikipedia.org/wiki/Density_of_air#Density_of_air_variables&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; for more detail.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Temperature&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;a 5° change can vary air density by almost 2%.   That means that the Sahara desert (35° c) and the North Pole (-25°), with humidity and pressure being equal, the air in the North Pole is about 24% denser.  Locally, if we assume a 15° variation daily or 25-35° variation yearly, that's 5%-14% locally, give or take, based on temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Pressure&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Per &lt;a href=&quot;https://en.wikipedia.org/wiki/Avogadro%27s_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Avogadro's law&lt;/a&gt;, a 10% increase in pressure, everything else being equal, corresponds to a 10% increase in gas density.  10% variation in air pressure is quite a bit (unless you're climbing a tall mountain).   Locally, 10% variation in air pressure is rare, unless you're looking at records.  Daily/Weekly highs and lows in barometric pressure might vary air density by 3%-7%, ballpark estimate.   See some record high and low pressure &lt;a href=&quot;https://www.wunderground.com/resources/pressure_records.asp&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Water Vapor&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Again, using Avogadro's law, if you add 1 water vapor molecule to the atmosphere, and maintain temperature and pressure, you need to push one other gas molecule out of the set volume, so per cubic meter, increasing humidity does displace some of the heavier gas molecules, so there is some lightening of the air, but the effect is quite small.  Water-vapor has a molecular mass of 18.  Our Oxygen-Nitrogen atmosphere has an average mass of about 29.   But Water Vapor rarely takes up more than 1% of the atmosphere, perhaps 2% in hot climate, 3% in very hot, but that's 3% of the air with a 38% decrease in mass, resulting in a net change of less than 1% in the most extreme conditions.  You'd be unlikely to see a variation of as much as 1% density by water vapor alone, outside of a very rare event, like a thunderstorm over a desert.     &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's other factors for wet air, such as the evaporation of water has a cooling effect, so as water evaporates, the local atmosphere cools, so mid day when sunlight driven or wind driven evaporation is at it's peak, it's not quite so neat and tidy as to say that evaporation makes the air lighter, cause the cooling effect of evaporation may actually make the air slightly more dense, not less dense.  It's only less dense if you keep everything equal, but the cooling effect of evaporation doesn't keep everything equal.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, however you look at it, water vapor is likely an order of magnitude less important for air-density than temperature and pressure.   It's relevant enough to pay attention too if you want to study air-density carefully, but temperature and pressure are the two big factors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A possible exception to this is when there's fog.  Fog contains tiny water droplets which are small enough to be suspended in air by wind, and those individual droplets are much denser than atmospheric water-vapor.   foggy air, under the right conditions might be the most dense air, but in a sense, that shouldn't count, it's like counting sand in a sandstorm as part of the mass of air.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;((Corrections welcome if I made any errors)).  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2017-03-14T05:51:15.257" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9904" PostTypeId="2" ParentId="9893" CreationDate="2017-03-14T07:33:43.993" Score="6" Body="&lt;p&gt;The Earth should probably be cooling, at least, that's what the Milankovich cycles and historical variation and recent temperature charts all indicate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;https://xkcd.com/1732/&quot; rel=&quot;nofollow noreferrer&quot;&gt;XKCD&lt;/a&gt; and related &lt;a href=&quot;https://earthscience.stackexchange.com/questions/8746/is-this-xkcd-comic-an-accurate-timeline-of-the-earths-average-temperature&quot;&gt;question on XKCD chart&lt;/a&gt;, and &lt;a href=&quot;https://earthobservatory.nasa.gov/Features/GlobalWarming/images/epica_temperature.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;temperature chart&lt;/a&gt; over the last 800,000 years.  &lt;a href=&quot;https://earthobservatory.nasa.gov/Features/GlobalWarming/page3.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, it should be pointed out that the Milankovich cycles don't line up in perfect synchronicity, so no two warm periods and no two ice ages should be exactly alike, but there are similarities, like a steady cooling after a warm period.   Earth has been gradually cooling for roughly the last 7,000 years, and this is due to the gradual changes in the Earth's orbit per &lt;a href=&quot;https://xkcd.com/1732/&quot; rel=&quot;nofollow noreferrer&quot;&gt;XKCD&lt;/a&gt;.   (scroll to 5,000 bce - see note).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If Earth cooled 1°C in 6,500 years and is due to cool 4°C in the next 10-30,000 years as the next ice age comes along, we can ballpark estimate 1 degree of cooling per 5,000 years, and if we use an estimate of 2 degrees warming by 2,100 and climate change took hold in the 1980s, that's 1 degree every 60 years current rate of warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, by my estimate, man is responsible for 101% of the current warming and Earth's natural cycles are shaving about 1% off man made climate change.   To say it's all us is accurate enough for me.   There's currently no natural warming of the Earth as far as I can tell, Earth should be cooling.   Granted there's variation, like the current solar cycle is a few tenths of a degree warmer than the maunder minimum that is believed to be the cause of the little ice age and our relative lack of major volcanic activity for much of this century might have a slight warming effect, so precise numbers are hard to pin down, but I think 101% man, -1% natural is pretty close to accurate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That part of the video begins about 2 minutes in, goes on for about 3 minutes, then it moves onto &quot;how would the Earth be different&quot; &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;If I may rant, there's several things I don't like about the interview.&#xA;Tucker Carson says 1:18  &quot;The essence of science is extreme skepticism&quot; - that just ain't so.   Skeptisism doesn't equal scientific discovery.   Bart Simpson is a skeptic - I don't think we should listen to his views on science.  Skeptisism is important to science but it is absolutely NOT the essence of science.   The essence of science is asking the right question and working out an answer through evidence and testing and peer review.   Peer review doesn't mean denial.  For Peer review to be meaningful, evidence or solid counter argument must be presented - not just empty skepticism.   Skepticism that ignores the evidence is about as valuable as a restaurant that doesn't serve any food.   Skeptics must respect and understand the evidence if they are going to provide intelligent skeptical arguments on why the evidence might mean something else.  If they don't do that, it's just noise.  Intelligent skepticism that respects the evidence and data is always welcome.   Uneducated skepticism is a pointless and senseless distraction.    It's like trying to form sentences without using any words.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But try explaining that to a skeptic sometime who thinks he doesn't need to be educated because skepticism is his education.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tucker then says, about 1:50 &quot;the climate has always changed&quot; - again, not really.  There are periods of what might be called climate consistency and periods of climate change.   The climate isn't &quot;always&quot; changing, but it does change fairly frequently.   There's also some clarity on what constitutes a change - weather changes during the seasons, but that's not climate, not really.   Climate incorporates the seasons and year to year variations.  Real climate change, by my definition, happens every few thousand years - give or take, and big changes, with the current ice age cycle on a 100,000 year time-frame, big changes happen twice every 100,000 years, with the rise and fall of ice ages.   There's some room for opinion in this though, but &quot;always changing&quot;, a common phrase by deniers - but simply not accurate, not if you're talking about real change.   Now if you're talking about irrelevant change then, sure.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pretty much everything is always changing.   A human's height changes about 1/2 inch from when they wake up to when they go to bed,   A human in space grows a full inch, but, . . . I still say I'm 5'10 when asked and I'd say I'm 5'10 if I lived on the space station.  I don't say 5&quot;10 1/2 cause I just woke up.   Even though my height is always changing depending on how long I've been standing up, 5'10 is close enough.   Relevant, significant change is worth identifying.   Incidental or irrelevant change based on fluctuations that go back and forth mostly doesn't need to be identified.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, no, the CLIMATE is NOT always changing.   Weather is always changing, climate goes through periods of decades, centuries, sometimes Millennia, where it remains consistent enough that we can say it isn't changing.   &quot;The climate is always changing&quot; is a red herring.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Everything Bill said is true, though I wasn't crazy about his initial time scales &quot;change used to happen over millions of years&quot; and &quot;now it happens over decades and years&quot; - that's iffy, but mostly everything he said was true, but he didn't handle the interview very well.    Tucker's &lt;a href=&quot;https://en.wikipedia.org/wiki/Duane_Gish#Debates&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gish Gallop&lt;/a&gt; was successful.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When Tucker moves onto &quot;how would the Earth be different&quot;, Bill does answer him with specifics, but Tucker just pretends those aren't good answers and interrupts Bill or goes back to the first question when he doesn't like that his 2nd question is being answered.    Overall it's a terrible interview designed to sell disinformation, not inform.   Painful to watch and I hate Fox News for that reason.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;OK, rant finished.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's no right answer.    101% - by my estimate.   100% if you believe the Earth isn't getting cooler.  102% or more if you set the rate of cooling a little higher, with the next ice age due in 10,000 years not 20,000 years.    (as of now, the next ice age is on indefinite delay - but that's another story).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or, the answer could be, 70-90% if you believe there's an un-accounted for natural warming period over the last 30-40 years.  That's one of Judith Curry's arguments that climate change has gotten a natural push to make it look bigger than it is, but, she has no good proof, which is why she's mostly alone in that argument.  It's just something she's claiming.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;100% is a good answer too, and if you listen, Bill does say 100% at one point, but it's during an interruption and hard to hear.   &quot;We aren't sure but close to 100% is also a good answer&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If Tucker had asked me what percentage.   I'd have showed him XKCD's chart and said &quot;see this point here, the cooling began shortly after 5,000 BCE, at a rate about 100 times slower than the current warming.  101% is relatively consistent with past Milankovich cycles and past periods of cooling following a warm period between ice ages.  So, that's my answer.   101% of the current warming is man-made. &lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2017-03-14T07:33:43.993" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9905" PostTypeId="1" CreationDate="2017-03-14T13:15:07.860" Score="7" ViewCount="496" Body="&lt;p&gt;Lately, I have been thinking about biogas and the impact leaks might have on climate. Biogas is mostly methane, and we know that methane has a much higher global warming potential than $\sf{CO_2}$. There will inevitably be leaks from biogas production plants, vehicles running on biogas, and other infrastructure. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Norway, sorting of food waste has been introduced in many areas. This food waste is taken to a treatment facility where biogas is produced, and the leftovers from the biogas production are used as bio-fertiliser. The biogas is used to power buses and dustcarts in and around Oslo. The climate effect is then positive, since you are using a resource that would otherwise be wasted, potentially turning into methane at a landfill.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: how large would the leaks have to be to counteract the positive effects?&lt;/p&gt;&#xA;" OwnerUserId="7712" LastEditorUserId="2470" LastEditDate="2017-03-15T07:39:11.917" LastActivityDate="2017-03-22T12:35:15.403" Title="Methane leaks from biogas" Tags="|climate|climate-change|methane|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9906" PostTypeId="2" ParentId="9902" CreationDate="2017-03-14T13:22:44.093" Score="3" Body="&lt;p&gt;That's because the tropopause, the boundary between the troposphere and stratosphere, is highest in equatorial regions. The high amount energy from the Sun in equatorial regions makes for a lot of convection, which in turn pushes the tropopause to about 16 km above the surface (and sometimes to 18 km) in those equatorial regions. Near the poles, sinking air and reduced solar intensity makes the tropopause much closer to the surface, where it is only 8 km or so high.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The lapse rate in the upper troposphere is roughly the same as the dry adiabatic lapse rate, 9.8 °C/km. The 8 km difference between the tropopause height between equatorial and polar regions results in about 80 degrees more cooling in equatorial regions than polar ones.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-03-14T13:22:44.093" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="9907" PostTypeId="1" CreationDate="2017-03-14T15:30:58.517" Score="13" ViewCount="3346" Body="&lt;p&gt;&lt;strong&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Geomagnetic_reversal&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geomagnetic pole reversal&lt;/a&gt; is a &quot;regular&quot; phenomenon on Earth&lt;/strong&gt;. Although the interval pattern has been irregular at times (sometimes with millions of years of difference between change intervals), Earth has settled in the last 20 million years into a pattern of a pole reversal about every 200,000 - 300,000 years (source: &lt;a href=&quot;https://www.nasa.gov/topics/earth/features/2012-poleReversal.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA&lt;/a&gt;). Based on this pattern and the fact that the most recent pole-switch occurred ~&lt;a href=&quot;https://en.wikipedia.org/wiki/Brunhes%E2%80%93Matuyama_reversal&quot; rel=&quot;nofollow noreferrer&quot;&gt;780,000 years ago&lt;/a&gt;, &lt;strong&gt;the Earth is &quot;overdue&quot; for a pole switch&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question: &lt;strong&gt;How quickly does a pole switch occur?&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Is it instantaneous? Does it take years? Millennia?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Is the current movement of the pole part of a drawn-out switch, or is it just &quot;normal&quot; pole movement? Again, from &lt;a href=&quot;https://www.nasa.gov/topics/earth/features/2012-poleReversal.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The magnetic north pole has been creeping northward – by more than 600 miles (1,100 km) – since the early 19th century, when explorers first located it precisely. It is moving faster now, actually, as scientists estimate the pole is migrating northward about 40 miles per year, as opposed to about 10 miles per year in the early 20th century.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;From some previous research, it seems like it doesn't always make a &quot;clean&quot; switch either, with multiple poles appearing globally -- would this multi-pole extravaganza increase the switching time, or is it also normal?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="7536" LastEditorUserId="7536" LastEditDate="2018-06-01T03:21:45.017" LastActivityDate="2018-06-01T03:21:45.017" Title="How long does a magnetic pole reversal take to complete?" Tags="|geomagnetism|poles|paleomagnetism|time|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="9908" PostTypeId="1" CreationDate="2017-03-14T15:34:37.917" Score="6" ViewCount="3547" Body="&lt;p&gt;The titles of many geology articles contain words like &quot;nappes and thrust sheets&quot;. Basically these are rather similar and in certain languages can be denoted with one term. The dictionaries tend to mix them giving the same translation for both. Is there any (subtle) difference or can they be considered synonims?&lt;/p&gt;&#xA;" OwnerUserId="7714" LastActivityDate="2017-04-17T03:49:35.033" Title="What is the difference between nappe and thrust sheet?" Tags="|geology|tectonics|terminology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9910" PostTypeId="2" ParentId="9890" CreationDate="2017-03-16T06:07:36.410" Score="0" Body="&lt;p&gt;I think I have the answer. Charges are dropped on the ground. This generates a wave underneath the surface of the earth. Analysing the time the waves take to return provides valuable information about rock types and possible gases or fluids in rock formations. This is similar to the use of ultrasound in medicine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two primary means of generating these waves: with dynamite and with a process called vibroseis. These charges in the movie must have been dynamite. &lt;/p&gt;&#xA;" OwnerUserId="7504" LastActivityDate="2017-03-16T06:07:36.410" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9911" PostTypeId="1" CreationDate="2017-03-16T08:14:03.033" Score="4" ViewCount="679" Body="&lt;p&gt;The ability of greenhouse gases to trap heat and re-radiate some of it back to the original heat source looks like a useful thermal property which could possibly be incorporated in things like double glazing, wall insulation, etc. What are the formulae which will enable us to calculate this additional thermal effect on top of the normal conductive heat loss parameters, heat capacity, U values etc ? We would also like to find details of the original experiments which were used to confirm the accuracy of said formulae as all I can find with internet searches are the well know school type experiments with plastic bottles and heat lamps which demonstrate the principle but are not sufficiently quantitatively accurate. &#xA;We asked a similar question in Physics Stack Exchange as we considered it a question relating to fundamental physical (thermal) properties of gases but it got little response. &lt;/p&gt;&#xA;" OwnerUserId="7722" LastActivityDate="2017-03-18T01:02:42.713" Title="What are the formulae for calculating the thermal heating effect of back radiation in greenhouse gases?" Tags="|atmosphere|climate-change|climate-models|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9912" PostTypeId="2" ParentId="6533" CreationDate="2017-03-16T09:58:24.700" Score="-3" Body="&lt;p&gt;The question I'm answering is:  Is it physically possible to see mountains from 500 km away?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is very likely possible to see the top of Mt. Everest from the top of some mountain that is 500+ km distant. The other mountain would have to be at least 10000 feet high and be located 500 - 550 km from Mt Everest, and there has to be no other mountains blocking the view.  Much better would be a 20000 ft high mountain because then you could see over 10000 ft high mountains in between &lt;/p&gt;&#xA;" OwnerUserId="7723" LastActivityDate="2017-03-16T09:58:24.700" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9913" PostTypeId="2" ParentId="9908" CreationDate="2017-03-16T13:10:18.017" Score="1" Body="&lt;p&gt;Nappes and thrust sheets are very similar terms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I agree with definition found on &lt;a href=&quot;https://en.wikipedia.org/wiki/Nappe&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia&lt;/a&gt;:&lt;br&gt;&#xA;(except for the 2 km requirement of movement, I would replace 2 km with significant distance.  I am sure you still have a Nappe with only 1.5 km of movement is measured.)  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In geology, a nappe or thrust sheet is a large sheetlike body of rock that has been moved more than 2 km (1.2 mi) or 5 km (3.1 mi) above a thrust fault from its original position. Nappes form in compressional tectonic settings like continental collision zones or on the overriding plate in active subduction zones. Nappes form when a mass of rock is forced (or &quot;thrust&quot;) over another rock mass, typically on a low angle fault plane. The resulting structure may include large-scale recumbent folds, shearing along the fault plane, imbricate thrust stacks, fensters and klippe.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-03-16T13:10:18.017" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9914" PostTypeId="1" AcceptedAnswerId="9918" CreationDate="2017-03-16T13:56:53.380" Score="8" ViewCount="1214" Body="&lt;p&gt;I would like to calculate the latitude values of a &lt;a href=&quot;https://en.wikipedia.org/wiki/Gaussian_grid&quot; rel=&quot;noreferrer&quot;&gt;Gaussian Grid&lt;/a&gt; of a size of my choosing. Unfortunately, I didn't find a method or a formula to do so. Where can I find this information? Alternatively, is there a function publicly available that can do the job?&lt;/p&gt;&#xA;" OwnerUserId="7724" LastActivityDate="2017-08-09T14:54:49.837" Title="Calculate the latitudes of a Gaussian Grid" Tags="|meteorology|weather-forecasting|climate-models|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9915" PostTypeId="2" ParentId="9907" CreationDate="2017-03-16T16:19:25.760" Score="12" Body="&lt;p&gt;The entire process appears to take 3,000-4,000 years, according to Valet and Fournier's May 2016 review article &quot;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2015RG000506/full&quot; rel=&quot;noreferrer&quot;&gt;Deciphering records of geomagnetic reversals&lt;/a&gt;,&quot; which was published in AGU's &lt;a href=&quot;http://agupubs.onlinelibrary.wiley.com/hub/journal/10.1002/(ISSN)1944-9208/&quot; rel=&quot;noreferrer&quot;&gt;Reviews of Geophysics&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The complex dynamical structure of reversals is supported by&#xA;  sedimentary and volcanic records. Provided that resolution is&#xA;  adequate, the reversal process seems to incorporate one precursor and&#xA;  one rebound prior to and after the transition. However, the three&#xA;  phases are rarely observed in a single record. This is likely to be&#xA;  caused both by field geometry and recording limitations. The duration&#xA;  of each phase does not exceed 3–4 kyr. Therefore, precursors and&#xA;  rebounds can be seen as part of the whole process, and the expression&#xA;  of a continuum of behavior between secular variation, excursions, and&#xA;  reversals. Another possibility is that the dipole collapse is not&#xA;  large enough or that the nondipole/dipole ratio varies.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Better resolution of the process and the time involved will require at least a 10-fold improvement in paleomagnetic sampling resolution, the authors contend. And one of the challenges is finding suitable lava flows or sediment layers that were created during the transition(s) in question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for whether current fluctuations indicate the earth is about to have a reversal: We can't tell, because the recent paleomagnetic record includes similar changes (sometimes regional rather than global) that did not result in reversals, Valet and Fournier write.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The present evolution falls within the normal range of field&#xA;  variability that prevailed for the past 2 Ma.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7314" LastEditorUserId="7314" LastEditDate="2017-03-16T16:31:34.907" LastActivityDate="2017-03-16T16:31:34.907" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9916" PostTypeId="2" ParentId="9911" CreationDate="2017-03-17T00:50:09.400" Score="2" Body="&lt;p&gt;As you have mentioned already, there are several physical phenomena which are responsible for heat and energy transfer. I'll just list them again for completeness, although you already addressed them in your question.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Conduction&lt;/li&gt;&#xA;&lt;li&gt;Convection&lt;/li&gt;&#xA;&lt;li&gt;Latent heat of vaporization&lt;/li&gt;&#xA;&lt;li&gt;Radiation&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;To get to your question: Radiation is the transport of energy by means of electromagnetic waves emitted from a body of a absoulte temperature uneqal zero Kelvin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What does that mean? Radiation does not rely on contact or a transporting fluid as do conduction and convection. Instead it is equivalent to the fourth power of its absolute Temperature. This is what we know as &quot;Black Body Radiation&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The equation for this is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ E = \sigma * T^4$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where σ is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_constant&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stefan-Boltzman Constant&lt;/a&gt; and T is the absolute Temperature in Kelvin. This law is obtained by integrating Planck's law over the solid angle and wavelength, in order to determinate the energy which is transmitted not only by one particular wavelength, but the whole spectrum and in all directions. Combined with &lt;a href=&quot;https://en.wikipedia.org/wiki/Kirchhoff%27s_law_of_thermal_radiation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kirchhoffs Law&lt;/a&gt;, which says, that the absorbtivity of an object equals its emissivity, you can calculate the radiated Energy of any object or atmospheric layer.&#xA;The emissivity (ε) of a body is a value between zero and one with one being the perfect black body. For most things you can find values in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Emissivity&quot; rel=&quot;nofollow noreferrer&quot;&gt;web&lt;/a&gt;. It also explains why aluminum foil is such a good insulator.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ E = ε * \sigma * T^4$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To put all of this in an example:&#xA;Everything around you radiates heat. Beginning with the most obvious, the sun. The sun's surface has an approximate temperature of 6000K. This means it emits radiation of the following spectrum:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QT9ok.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QT9ok.png&quot; alt=&quot;https://upload.wikimedia.org/wikipedia/commons/e/e7/Solar_spectrum_en.svg&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, the maximum of the energy of the sun is radiated in the part which we know as visible light. Also a big part of the radiated energy is absorbed in the atmosphere (the difference between yellow and red graphs). Responsible for these are particularly Ozone (O3), Water (H2O) and (CO2) which are also our most important greenhouse gases. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What happens, is that the radiated energy of a particular wavelength &quot;hits&quot; the molecules and excites them into a state of higher kinetic energy. The average random kinetic energy of a substance is what we know as the temperature of this substance. Hence, also the atmosphere acts like a black body and radiates energy &#xA;back to space but also back to earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately I can't really say much about the second part of your question. I don't know about the original experiments. But I suggest a read about Gustav Kirchhoff, who introduced the idea in 1860 which then has been proceeded by Josef Stefan in 1879 and Ludwig Boltzman (1884). Also Planck's works from 1900 could be helpful.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope I was able to point you in the right direction with your studies.&lt;/p&gt;&#xA;" OwnerUserId="7295" LastActivityDate="2017-03-17T00:50:09.400" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9918" PostTypeId="2" ParentId="9914" CreationDate="2017-03-17T08:28:59.690" Score="6" Body="&lt;p&gt;I believe the NCL function &lt;a href=&quot;http://www.ncl.ucar.edu/Document/Functions/Built-in/gaus.shtml&quot; rel=&quot;noreferrer&quot;&gt;NCL gaus&lt;/a&gt; should be able to give you the solution you are looking for. From the API documentation you are requested to provide - the number of latitude points per hemisphere and you should get Gaussian latitudes and Gaussian weights. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a code sample from their website &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;nlat = 64  ; for globe&#xA;gau_info = gaus(nlat/2)   ; divide by 2 to get &quot;per hemisphere&quot;&#xA;glat     = gau_info(:,0)  ; gaussian latitudes ( 1st dimension of gau_info)&#xA;gwgt     = gau_info(:,1)  ; gaussian weights   ( 2nd dimension of gau_info) &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerDisplayName="user1066" LastActivityDate="2017-03-17T08:28:59.690" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9919" PostTypeId="1" CreationDate="2017-03-06T12:14:59.773" Score="3" ViewCount="314" Body="&lt;p&gt;Are there studies showing the relative positions carbon footprints of various countries? &lt;strong&gt;which one produce how much greenhouse gases&lt;/strong&gt;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm interested in comparing developing and developed countries and continents, and prefer university studies wherever possible.&lt;/p&gt;&#xA;" OwnerUserId="7647" OwnerDisplayName="user q...d7...6" LastActivityDate="2017-04-13T16:35:53.840" Title="Relative world carbon footprints by nation?" Tags="|climate-change|" AnswerCount="3" CommentCount="3" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9920" PostTypeId="2" ParentId="9919" CreationDate="2017-03-06T15:02:08.437" Score="0" Body="&lt;p&gt;You start with IPCC reports (&lt;a href=&quot;http://www.ipcc.ch/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.ipcc.ch/&lt;/a&gt;) (they are extensive, and maybe (surely) there is something about global warming variations between countries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can also use google and in particular the &quot;Google Scholar&quot; search to find out about University research, most major university have climate research going on.&#xA;for example (one of many), one starting point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Stanford: &lt;a href=&quot;http://solar-center.stanford.edu/sun-on-earth/glob-warm.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://solar-center.stanford.edu/sun-on-earth/glob-warm.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since there are at least hundreds of university that does global warming research it will be hard to help you single out for you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Good luck with that.&lt;/p&gt;&#xA;" OwnerDisplayName="Max" LastActivityDate="2017-03-06T15:02:08.437" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9921" PostTypeId="2" ParentId="9919" CreationDate="2017-03-06T15:32:44.253" Score="1" Body="&lt;h2&gt;&lt;a href=&quot;http://environmentalresearchweb.org/cws/article/news/67902&quot; rel=&quot;nofollow noreferrer&quot;&gt;The answer is no&lt;/a&gt;.&lt;/h2&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;The search for a single and simple measure for each country’s contribution to global warming is unlikely to succeed&lt;/strong&gt;, new research has warned.&lt;/p&gt;&#xA;&lt;p&gt;The question of how to fairly quantify national contributions to global warming historically, and inform future policy on sharing the burden of reducing greenhouse gas emissions, has long been part of international discussions on global warming.&lt;/p&gt;&#xA;&lt;p&gt;Researchers from the Center for International Climate and Environmental Research Oslo (CICERO) and the University of Oxford, UK, assessed if finding an answer to this question was possible or likely.&lt;/p&gt;&#xA;&lt;p&gt;Dr Steffen Kallbekken, from CICERO, said: “There are vast differences in income, population, resources, technologies and capacity across countries. Because of this, the idea of distributive fairness has played a crucial role in the international climate policy debate.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;“However, trying to find a single common formula for policymakers to decide the distribution of national efforts in a climate agreement was never likely to succeed.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;“Although it references equality principles, the United Nations Framework Convention on Climate Change 2016 Paris Agreement tacitly recognises this fact, as in practice the differentiation is left to each country to decide for itself.”&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;Dr Jan Fuglestvedt said: “Our results indicate there is no simple and single correct answer to the question of how much each country has contributed to global warming. There are too many fundamental value-related and ethical questions remaining, to which it is impossible to find a single answer.&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;“A more useful approach would be for scientific studies to present not just one set of calculated contributions – based on some of many choices – instead present a spectrum of results showing how the contributions vary according to a broad set of choices.”&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="Venture2099" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-03-06T15:39:34.063" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9922" PostTypeId="1" CreationDate="2017-03-17T15:19:32.517" Score="10" ViewCount="101" Body="&lt;p&gt;I'm trying to understand transpiration estimation methods. The FAO recommends a standard Penman-Monteith methodology for modeling evapotranspiration based on meteorological and vegetation parameters (ie. wind speed, leaf area index). Many eco-hydrology models make use of the Penman-Monteith equations, some with minor modifications.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand the Penman-Monteith equations, and modification thereof, are simplifications of complex processes. It would be impractical to measure actual transpiration in all conditions where that information is useful, so we model it instead. That said, field observations in the development or support of models is valuable for verifying knowledge gained through models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: &lt;strong&gt;what field studies have developed or supported Penman-Monteith equations (or modified versions of it)?&lt;/strong&gt; In a sense there is &lt;em&gt;indirect&lt;/em&gt; verification of the equations through field measurement verification of results from models that implement the Penman-Monteith equations. Are there any direct field measurements of (evapo-)transpiration that support (or even helped develop) the Penman-Monteith equations, to demonstrate the equations' validity in real world conditions?&lt;/p&gt;&#xA;" OwnerUserId="4789" LastActivityDate="2017-04-20T08:19:15.250" Title="What field studies have developed or supported the Penman-Monteith equations for estimating evapotranspiration?" Tags="|models|hydrology|measurements|vegetation|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="9923" PostTypeId="1" CreationDate="2017-03-17T16:00:23.710" Score="3" ViewCount="44" Body="&lt;p&gt;A few years ago &lt;a href=&quot;https://earthscience.stackexchange.com/questions/51/what-are-the-impacts-of-sublimation-on-an-annual-mountain-snowpack&quot;&gt;another question touched on the relative rates of sublimation versus melting&lt;/a&gt; in terms of snow and snow pack disappearance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What was unusual about the answer is the huge range of variability in the results from different studies. One study claiming only 2% of ablation was due to sublimation and another claiming almost all of it was. I vaguely remember an extensive New Zealand study (not shown in the answer) that had a result showing about half of ablation is due to irradiation (sublimation).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has this subject been revisited by more thorough-going studies that answer the question definitively?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In my own view, it would seem that &quot;backyard&quot; experiments could be done on snow drifts to answer this question. In my mind there should be no one single numeric answer but rather a table which relates several factors:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the underlying ground material and strata (sandy soil, rock, asphalt, etc)&lt;/li&gt;&#xA;&lt;li&gt;the air temperature&lt;/li&gt;&#xA;&lt;li&gt;the latitude and time (= inclination to the sun)&lt;/li&gt;&#xA;&lt;li&gt;surface area exposed to sun&lt;/li&gt;&#xA;&lt;li&gt;surface area exposed to ground&lt;/li&gt;&#xA;&lt;li&gt;volume of frozen accumulation&lt;/li&gt;&#xA;&lt;li&gt;type of frozen accumulation (dry snow, wet snow, ice)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Based on these factors it should be possible using the principles of thermodynamics and physical experiments to create tables (or equations) that define ablation in terms of these seven variables.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has any study been done to do this computation?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastEditorUserId="-1" LastEditDate="2017-04-13T12:50:30.540" LastActivityDate="2017-03-17T16:00:23.710" Title="Phase conversion of snow and ice due to irradiation versus melting" Tags="|ice|snow|thermodynamics|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9925" PostTypeId="1" CreationDate="2017-03-18T00:42:09.847" Score="3" ViewCount="256" Body="&lt;p&gt;I am interested to know if there is any place on Earth that is permanently a desert (except Antarctica). By permanent I do not mean to be the physical meaning of forever. It means the place has to be at least staying million of years as a desert and had survived at least one major climate change period. Precipitation is probably the most important factor to determine if a place would be a desert. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, the question could be focused on a particular location which receive little precipitation despite how the overall global climate has changed (of course I still welcome discussion outside of the precipitation pattern).&lt;/p&gt;&#xA;" OwnerUserId="3241" LastEditorUserId="3241" LastEditDate="2017-03-18T23:14:44.690" LastActivityDate="2017-03-18T23:14:44.690" Title="Is there any place on Earth that is permanently a desert?" Tags="|climate|earth-history|precipitation|desert|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9926" PostTypeId="2" ParentId="9911" CreationDate="2017-03-18T01:02:42.713" Score="0" Body="&lt;p&gt;It is important to remember a number of things about the basic Stefan-Boltzmann equation. It is supposed to apply to a spherical black body at uniform temperature. This is a hypothetical thing ! It is spherical because if you have an irregular shaped object parts of it can radiate back onto itself. It is also supposed to be a body i.e. have a surface from which the radiation can be emitted (and also absorbed). This makes it trickier to use with something that is partially transparent to radiation i.e. some radiation can pass right through it (like gases). Of course we can adjust the basic S-B equation with an emissivity factor where a real world object is concerned. Finding an emissivity value for a gas is a bit tricky too. Especially when mixed with other gases. Even if pure, there can be a quite wide range of values, pure CO2 could be as low as 0.002 .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you have done all that however you need to understand something basic. The S-B equation gives you a figure for the radiative flux. It is NOT a figure for heat transfer. To obtain a figure for the actual heat transfer you need the temperature of the cold object (double glazing gas filling or earth atmosphere) and the temperature of the hot object (interior room or earth surface). S-B will give you the radiative HEAT transfer from the hot source to the cold sink. There is no heat transfer the other way even though there is radiation transfer both ways. Consider it as a NET radiative flux transfer if you like. The radiative flux which flows from the cold object to the hot one changes the net outflow of actual heat from the hot object, i.e. its rate of cooling will be slowed. This is effectively the same type of thing as insulation in a conductive or convective sense. The more insulation there is the slower the rate of cooling of the hot object.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So for the Earth's atmosphere we can see that the so called &quot;back radiation&quot; (same as the measurable down welling long wave IR) are not transfering heat from anything but are in fact changing the net radiative flux at the earth's surface and thus slowing down it's rate of heat loss. The back radiation is not making the surface of the earth hotter per se but making it less cool when it loses heat. If you can get an equivalent effect to the atmospheric greenhouse gas effect by putting pure CO2 in a double glazing unit I wouldn't like to guess. I suspect the effect may be small but some lab experiments carefully designed to just measure radiation effects and eliminate conduction/convection would be a good idea. I am not aware of any past experiments having been done on this.       &lt;/p&gt;&#xA;" OwnerUserId="7733" LastActivityDate="2017-03-18T01:02:42.713" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9928" PostTypeId="2" ParentId="9675" CreationDate="2017-03-18T01:48:15.740" Score="-2" Body="&lt;p&gt;No, they are not representative. Scientifically not ideal. You wouldn't start from there if you had today's plan BUT it is all you have got. When you have imperfect data you have to be honest and point out it's imperfections and, if possible, calculate or estimate the effect of those imperfections on your results/conclusions. Whether or not the clever climatologists have done so to the necessary degree is beyond me (maybe it's not beyond you ?). Early IPCC reports seemed to have plenty of &quot;not sure&quot; &quot;inconclusive&quot; &quot;insufficient data&quot; comments but these have, of course, somewhat reduced in number.The reason is not better historical data, you still have the same old data you had before, but clearly better &quot;treatment&quot;. Whether the data has been tortured by humans or integrated circuits is again beyond me. Perhaps it has not been tortured at all. If we wanted to examine a prisoner who claimed he had been tortured when the guards said they &quot;didn't touch him, gov !&quot; We would have a look beneath his clothes at his skin. So get the climatoligist to show you how exactly they treated their data, get the outer layer of clothes stripped off, and ask them to explain those bruise marks. Be suspicious of anyone who says it was an accident while playing hockey.    &lt;/p&gt;&#xA;" OwnerUserId="7733" LastActivityDate="2017-03-18T01:48:15.740" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9930" PostTypeId="2" ParentId="9905" CreationDate="2017-03-18T09:24:36.440" Score="-4" Body="&lt;p&gt;This cannot reliably be answered.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To work out whether something is better, worse or the same scientifically you need first the theory of what thing changes what other thing and secondly the formulae to calculate it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regard to the CO2 in the atmosphere we have a theory that more CO2 will make the Earth hotter. We do not, as yet, have an accurate formula.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Answering the question for CO2 is tricky. We think we know what is happening but it's not yet at the stage we can calculate it accurately. This is why IPCC reports on predicted global warming have ranges with degrees of certainty. Maybe doubling CO2 in the atmosphere will increase average global temperature by 0.7 degrees in 100 years, maybe it will be 7 degrees. Not really sure yet, still working on it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if it has taken this long, with this much money, to get as far as this fuzzyness with CO2 I doubt we can answer your question in your lifetime for methane. &lt;/p&gt;&#xA;" OwnerUserId="7733" LastEditorUserId="595" LastEditDate="2017-03-20T20:08:33.203" LastActivityDate="2017-03-20T20:08:33.203" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9931" PostTypeId="2" ParentId="7328" CreationDate="2017-03-18T12:43:18.950" Score="2" Body="&lt;p&gt;Try Mayavi - &lt;a href=&quot;http://docs.enthought.com/mayavi/mayavi/mlab.html#id1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mayavi 3D Python plotting&lt;/a&gt;. You can supply the u,v,w components of the wind vector  as input and plot a 3D diagram&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/X8scB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/X8scB.jpg&quot; alt=&quot;3D plot of vector wind&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastActivityDate="2017-03-18T12:43:18.950" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9934" PostTypeId="2" ParentId="9925" CreationDate="2017-03-18T20:48:44.580" Score="7" Body="&lt;p&gt;UserLTK, above, has mentioned the Dry Valleys of Antarctica and the Atacama desert as two notable examples of &quot;permanent&quot; deserts. It's likely that these two locations have been deserts for at lease several millions of years despite changes in global weather patterns from multiple glacial events. The Atacama is well shielded by a very old mountain range to the west, and the Dry Valleys are also well protected by both an inland location and by global ocean currents that isolate the continent from much of the world's weather.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-03-18T20:48:44.580" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9937" PostTypeId="2" ParentId="9890" CreationDate="2017-03-19T13:55:28.677" Score="3" Body="&lt;p&gt;Explosives are just one way we can produce seismic waves in the ground. By placing geophones on the surface, which measure the rate of change of displacement of the surface, we can actually guess where there are boundaries between different rock types in the subsurface. When we detonate our chosen 'seismic wave generator' the geophones begin recording this change in displacement. As the seismic waves propagate and hit boundaries between rocks of different acoustic impedances (resistance to propagation of seismic waves) some of that wave energy will reflect back to the surface and some will be transmitted downward (&lt;a href=&quot;http://petrowiki.org/Seismic_wave_propagation#Reflection_coefficients&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://petrowiki.org/Seismic_wave_propagation#Reflection_coefficients&lt;/a&gt;). The amplitude and sign (positive/negative) of those recorded wiggles tell us about how big the contrast in acoustic impedance is as well as if acoustic impedance is increasing/decreasing downwards. This allows us to produce a picture of the subsurface where the x-axis is offset of the geophones from the wave source and the y-axis is the time it takes for the wave to travel down and back up as shown in this picture:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XMhoQ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XMhoQ.png&quot; alt=&quot;Example seismic section&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However it is never that simple. A lot of processing has to be done to make sure our initial image is the most accurate picture of the subsurface we can make and even then there is still uncertainty. It must also be stressed that we don't actually know about the properties of the rocks themselves just that boundaries exist between these rocks. If we want to estimate that we can use processes such as seismic inversion. &lt;/p&gt;&#xA;" OwnerUserId="6997" LastEditorUserId="6997" LastEditDate="2017-03-19T14:00:56.610" LastActivityDate="2017-03-19T14:00:56.610" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9938" PostTypeId="1" CreationDate="2017-03-19T16:12:32.677" Score="6" ViewCount="1474" Body="&lt;p&gt;I've been trying to run WRF-Chem with my emissions but they are not being read by WRF-Chem. RADM2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have emissions for the whole week, so &lt;code&gt;io_style_emissions = 2&lt;/code&gt; and the emissions are in &lt;code&gt;wrfchem_d01_2014_08_04_00:00:00&lt;/code&gt; format, just one emissions file. I thought &lt;code&gt;io_form_auxinput5 == 11&lt;/code&gt;, but I have error I had to comment that line in &lt;code&gt;namelist.input&lt;/code&gt;, and maybe that is the reason. I could model with 2 12-hours emissions files but that is not my goal, because I developed the emissions model, with high resolution temporal and spatial, and I would lose to much information otherwise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The whole configuration for running WRF is &lt;a href=&quot;https://hackmd.io/s/B1hsu6qol&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WWl1K.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WWl1K.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JimBm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JimBm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6489" LastEditorUserId="124" LastEditDate="2017-03-24T21:49:51.980" LastActivityDate="2020-03-21T08:39:54.593" Title="Why is WRF-Chem not reading my emissions data?" Tags="|models|atmosphere-modelling|wrf|wrf-chem|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9939" PostTypeId="1" CreationDate="2017-03-19T18:21:51.987" Score="3" ViewCount="254" Body="&lt;p&gt;A fault that ruptures causing an earthquake, can cause a chain reaction of dynamically triggered earthquakes in nearby faults, thus causing a much larger seismic event. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What could be some unlikely but still plausible, or creative ways to stop this chain reaction of earthquakes, so that e.g. a major city can be saved?&lt;/p&gt;&#xA;" OwnerUserId="7737" LastEditorUserId="2536" LastEditDate="2017-05-28T10:02:00.047" LastActivityDate="2017-05-28T10:02:00.047" Title="How could an earthquake be stopped once triggered?" Tags="|geology|earthquakes|natural-disasters|geoengineering|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9940" PostTypeId="2" ParentId="9939" CreationDate="2017-03-20T02:56:37.957" Score="1" Body="&lt;p&gt;This is a very big stretch of the imagination and the technology to do so does not exist and most likely never will. But, adapting noise cancelling technology to cancelling the waves produced by earthquakes could be considered.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A system to do so would require an earthquake monitoring system coupled with a wave &amp;amp; strength analysis system that would then produce an out of phase wave pattern to cancel out the earthquake waves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some of the problems with this would be the response times required &amp;amp; how to generate a out of phase wave system of equal magnitude to the earthquake waves. Extreme care would be needed so that the out of phase wave generator did not cause a similar amount of damage, or more, than the earthquake waves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, the out of phase wave generator would need to be able to produce wave patterns at extreme short notice, repeatedly &amp;amp; possible continuously to ensure immediate responses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The wave generator would also have to produce waves of extreme complexity in three dimensions from pulse waves to shearing type waves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To ensure fast analysis times of complex wave patterns, quantum computers (which currently do not exist) would need to be used.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Such a system would be complex and expensive.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2017-03-20T03:07:49.643" LastActivityDate="2017-03-20T03:07:49.643" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9942" PostTypeId="1" CreationDate="2017-03-20T18:22:47.110" Score="3" ViewCount="155" Body="&lt;p&gt;I am looking for some technique or machine developed to estimate how deep is a hard rock starting around 100 meter below earth surface. If somebody wants to estimate how deep is that hard rock, how can they know is there any method implemented and used around the world?&lt;/p&gt;&#xA;" OwnerUserId="7742" LastActivityDate="2017-03-22T13:31:47.287" Title="is there any technique developed that can estimate depth of bedrock?" Tags="|bedrock|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9943" PostTypeId="1" CreationDate="2017-03-20T21:29:31.207" Score="1" ViewCount="639" Body="&lt;p&gt;I am trying to run WRF 3.8.1 using ncep2 but after a while the run stops and I get following error:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;rsl.error.0211:forrtl: error (69): process interrupted (SIGINT)&#xA;rsl.error.0212:forrtl: error (69): process interrupted (SIGINT)&#xA;rsl.error.0213:forrtl: error (69): process interrupted (SIGINT)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;I tried setting following in by &lt;code&gt;.bashrc&lt;/code&gt; file:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;ulimit-n -s unlimited&#xA;export OMP_STACKSIZE=64m&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;but the problem still is there and nothing improved. Any suggestions please? Thank you!&lt;/p&gt;&#xA;" OwnerUserId="7746" LastEditorUserId="5594" LastEditDate="2017-03-22T16:49:38.843" LastActivityDate="2017-03-22T16:49:38.843" Title="SIGINT error WRF" Tags="|atmosphere-modelling|wrf|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="9944" PostTypeId="2" ParentId="9942" CreationDate="2017-03-21T02:41:15.720" Score="1" Body="&lt;p&gt;Sonar (passive or active) or ground penetrating radar with both work, it can also be estimated from a published geologic profile of the area which are often built from both in addition to drill data. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2017-03-22T13:31:47.287" LastActivityDate="2017-03-22T13:31:47.287" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9945" PostTypeId="2" ParentId="6684" CreationDate="2017-03-21T11:04:32.873" Score="5" Body="&lt;p&gt;Evans has been making predictions of this nature for a while, for example, from 2014:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://joannenova.com.au/2014/06/big-news-viii-new-solar-model-predicts-imminent-global-cooling/&quot; rel=&quot;nofollow noreferrer&quot;&gt;&amp;quot;It’s already baked in the cake; we can see a few years into the future.&amp;quot;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/N3KK0.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/N3KK0.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The prediction isn't looking too good so far&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xaSXR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xaSXR.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="624" LastEditorUserId="624" LastEditDate="2022-05-24T14:32:59.490" LastActivityDate="2022-05-24T14:32:59.490" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="9946" PostTypeId="1" CreationDate="2017-03-21T15:01:06.603" Score="3" ViewCount="556" Body="&lt;p&gt;We all know that the water on Earth came from asteroids that collided on the Earth. But how does water form in the asteroids?&lt;/p&gt;&#xA;" OwnerUserId="7504" LastActivityDate="2017-03-21T15:45:54.707" Title="From where do asteroids get water from?" Tags="|water|" AnswerCount="1" CommentCount="6" ClosedDate="2017-03-21T17:47:06.810" ContentLicense="CC BY-SA 3.0" />
  <row Id="9947" PostTypeId="2" ParentId="9946" CreationDate="2017-03-21T15:45:54.707" Score="1" Body="&lt;p&gt;hydrogen is the most common element in the universe, Oxygen is the third most common element in the universe, hydrogen + oxygen + heat/energy = water. Water is literally the most common compound in the universe.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2017-03-21T15:45:54.707" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9948" PostTypeId="2" ParentId="9942" CreationDate="2017-03-21T16:51:43.373" Score="3" Body="&lt;p&gt;A small scale seismic survey as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I remember as students we found the water table using a 100m refraction line and a sledge hammer sound source. Scale that up from ~5m to 100m you're going to need a longer line and a larger sound source. Reflection might also become more convenient. Still a lot smaller than a typical 2d survey line though!&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2017-03-21T16:51:43.373" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9949" PostTypeId="2" ParentId="5269" CreationDate="2017-03-21T18:01:22.350" Score="4" Body="&lt;p&gt;The same as scottlittle, but you can use also McIdas V. It also can read nedcdf files and also is a free software.&#xA;&lt;a href=&quot;http://www.ssec.wisc.edu/mcidas/software/v/documentation.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.ssec.wisc.edu/mcidas/software/v/documentation.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7754" LastActivityDate="2017-03-21T18:01:22.350" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9950" PostTypeId="2" ParentId="9938" CreationDate="2017-03-21T23:22:01.577" Score="4" Body="&lt;p&gt;I could run model, i just had to change a bit the namelist. I added three parameters:io_form_auxinput5 = 2,auxinput5_inname = 'wrfchemi_d$&amp;lt;domain&amp;gt;$_$&amp;lt;date&amp;gt;$'  and frames_per_auxinput5                = 168. (168 hours of emissions and hours of simulation)&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;&amp;amp;time_control&#xA; run_days                            = 0,&#xA; run_hours                           = 0,&#xA; run_minutes                         = 0,&#xA; run_seconds                         = 0,&#xA; start_year                          = 2014,&#xA; start_month                         = 08,&#xA; start_day                           = 04,&#xA; start_hour                          = 00,&#xA; start_minute                        = 00,&#xA; start_second                        = 00,&#xA; end_year                            = 2014,&#xA; end_month                           = 08,&#xA; end_day                             = 11,&#xA; end_hour                            = 00,&#xA; end_minute                          = 00,&#xA; end_second                          = 00,&#xA; interval_seconds                    = 21600&#xA; input_from_file                     = .true.,.true.,.true.,&#xA; history_interval                    = 60,&#xA; history_outname                     = &quot;/scr4/sibarra/masp/run2/1km/wrfout_d&amp;lt;domain&amp;gt;_&amp;lt;date&amp;gt;&quot;&#xA; frames_per_outfile                  = 5000,&#xA; restart                             = .false.,&#xA; restart_interval                    = 10080,&#xA; auxinput5_interval_m                = 60,   &#xA; io_form_auxinput2                   = 2,&#xA; io_form_auxinput5                   = 2,&#xA; auxinput5_inname                    = 'wrfchemi_d&amp;lt;domain&amp;gt;_&amp;lt;date&amp;gt;'&#xA; frames_per_auxinput5                = 168,&#xA; io_form_history                     = 2&#xA; io_form_restart                     = 2&#xA; io_form_input                       = 2&#xA; io_form_boundary                    = 2&#xA; debug_level                         = 100&#xA; /&#xA;&#xA; &amp;amp;domains&#xA; time_step                           = 6,&#xA; time_step_fract_num                 = 0,&#xA; time_step_fract_den                 = 1,&#xA; max_dom                             = 1,&#xA; e_we                                = 191,&#xA; e_sn                                = 181,&#xA; e_vert                              = 35,&#xA; p_top_requested                     = 5000,&#xA; num_metgrid_levels                  = 27,&#xA; vert_refine_fact                    = 1,&#xA; num_metgrid_soil_levels             = 4,&#xA; dx                                  = 1000,&#xA; dy                                  = 1000,&#xA; grid_id                             = 3,&#xA; parent_id                           = 2,&#xA; i_parent_start                      = 57,&#xA; j_parent_start                      = 59,&#xA; parent_grid_ratio                   = 5,&#xA; parent_time_step_ratio              = 5,&#xA; feedback                            = 1,&#xA; smooth_option                       = 0&#xA; /&#xA;&#xA; &amp;amp;physics&#xA; mp_physics                          = 2,&#xA; ra_lw_physics                       = 1,&#xA; ra_sw_physics                       = 2,&#xA; radt                                = 15,&#xA; sf_sfclay_physics                   = 1,&#xA; sf_surface_physics                  = 2,&#xA; bl_pbl_physics                      = 1,&#xA; bldt                                = 0,&#xA; cu_physics                          = 0,&#xA; cudt                                = 0,&#xA; cu_diag                             = 1,&#xA; cu_rad_feedback                     = .true.,&#xA; isfflx                              = 1,&#xA; ifsnow                              = 0,&#xA; icloud                              = 0,&#xA; surface_input_source                = 1,&#xA; num_soil_layers                     = 4,&#xA; num_land_cat                        = 20,&#xA; sf_urban_physics                    = 1,&#xA; /&#xA;&#xA; &amp;amp;fdda&#xA; /&#xA;&#xA; &amp;amp;dynamics&#xA; w_damping                           = 0,&#xA; diff_opt                            = 1,&#xA; km_opt                              = 4,&#xA; diff_6th_opt                        = 0,&#xA; diff_6th_factor                     = 0.12,&#xA; base_temp                           = 290.&#xA; damp_opt                            = 0,&#xA; zdamp                               = 5000.,&#xA; dampcoef                            = 0.2&#xA; khdif                               = 0,&#xA; kvdif                               = 0,&#xA; non_hydrostatic                     = .true., .true., .true.,&#xA; moist_adv_opt                       = 1,     &#xA; scalar_adv_opt                      = 1,     &#xA; /&#xA;&#xA; &amp;amp;bdy_control&#xA; spec_bdy_width                      = 5,&#xA; spec_zone                           = 1,&#xA; relax_zone                          = 4,&#xA; specified                           = .true., .false.,.false.,&#xA; nested                              = .false., .true., .true.,&#xA; /&#xA;&#xA; &amp;amp;grib2&#xA; /&#xA;&#xA; &amp;amp;chem&#xA; kemit                               = 1,&#xA; chem_opt                            = 1,&#xA; bioemdt                             = 15,&#xA; photdt                              = 15,&#xA; chemdt                              = 2.,&#xA; io_style_emissions                  = 2,&#xA; emiss_inpt_opt                      = 1,&#xA; emiss_opt                           = 2,&#xA; chem_in_opt                         = 1,&#xA; phot_opt                            = 2,&#xA; gas_drydep_opt                      = 1,&#xA; aer_drydep_opt                      = 0,&#xA; bio_emiss_opt                       = 0,&#xA; dust_opt                            = 0,&#xA; dmsemis_opt                         = 0,&#xA; seas_opt                            = 0,&#xA; gas_bc_opt                          = 1,&#xA; gas_ic_opt                          = 1,&#xA; aer_bc_opt                          = 1,&#xA; aer_ic_opt                          = 1,&#xA; aer_op_opt                          = 0,&#xA;! opt_pars_out                       = 0,&#xA; gaschem_onoff                       = 1,&#xA; aerchem_onoff                       = 1,&#xA; wetscav_onoff                       = 0,&#xA; cldchem_onoff                       = 0,&#xA; vertmix_onoff                       = 1,&#xA; chem_conv_tr                        = 0,&#xA; biomass_burn_opt                    = 0,&#xA; aer_ra_feedback                     = 0&#xA; have_bcs_chem                       = .false., .false., .false.,&#xA; /&#xA;&#xA; &amp;amp;namelist_quilt&#xA; nio_tasks_per_group = 0,&#xA; nio_groups = 1,&#xA;/&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="6489" LastEditorUserId="6489" LastEditDate="2017-03-24T18:13:08.817" LastActivityDate="2017-03-24T18:13:08.817" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9951" PostTypeId="1" CreationDate="2017-03-22T04:21:26.123" Score="3" ViewCount="2168" Body="&lt;p&gt;I have earlier used FNL, CFSR, Reanalysis-2 data set as input in WRF. However, I am finding it difficult to download ECMWF data as there are so many variables. Can anyone with experience in ECMWF let me know from where to download ECMWF data for WRF?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I need ERA-Interim Project to input into WRF. I have &lt;a href=&quot;https://rda.ucar.edu/datasets/ds627.0/&quot; rel=&quot;nofollow noreferrer&quot;&gt;the link&lt;/a&gt;, I just don't know which variables to download and how to input in WRF.&lt;/p&gt;&#xA;" OwnerUserId="7746" LastEditorUserId="106" LastEditDate="2017-03-29T13:22:25.070" LastActivityDate="2018-09-20T00:51:19.430" Title="ECMWF data as WRF input" Tags="|wrf|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9952" PostTypeId="2" ParentId="9951" CreationDate="2017-03-22T07:01:02.230" Score="4" Body="&lt;p&gt;For any of the basic forecast runs (10 day, ensembles, monthly/seasonal forecasts), I do not believe ECMWF data access is general controlled to &lt;a href=&quot;http://www.ecmwf.int/en/forecasts/datasets/catalogue-ecmwf-real-time-products&quot; rel=&quot;nofollow noreferrer&quot;&gt;ECMWF.INT&lt;/a&gt;.  Generally most data, including anywhere near enough to use in a WRF forecast, is only available for purchase &lt;a href=&quot;http://www.ecmwf.int/en/forecasts/accessing-forecasts/licences-available&quot; rel=&quot;nofollow noreferrer&quot;&gt;at extreme fees&lt;/a&gt; (generally we're talking 5+ figures per year).  The only option you might have is if you are doing your modeling for strictly research purposes, in which case you may qualify for a &lt;a href=&quot;http://www.ecmwf.int/en/forecasts/accessing-forecasts&quot; rel=&quot;nofollow noreferrer&quot;&gt;research license&lt;/a&gt; at reduced or free cost, or be able to access it from servers at the institution you are associated with.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It does appear that &lt;a href=&quot;http://www.ecmwf.int/en/research/climate-reanalysis/era-interim&quot; rel=&quot;nofollow noreferrer&quot;&gt;reanalysis data&lt;/a&gt; and various &lt;a href=&quot;http://apps.ecmwf.int/datasets/&quot; rel=&quot;nofollow noreferrer&quot;&gt;other specialized products&lt;/a&gt; are &lt;a href=&quot;https://software.ecmwf.int/wiki/display/WEBAPI/Access+ECMWF+Public+Datasets&quot; rel=&quot;nofollow noreferrer&quot;&gt;available free with an account at their website&lt;/a&gt; as described &lt;a href=&quot;https://software.ecmwf.int/wiki/display/WEBAPI/Access+ECMWF+Public+Datasets&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.  I believe reanalysis would only get you initial conditions which I don't believe is sufficient to run a mesoscale model like WRF(?), and that they are also poorer quality/resolution (please correct me if I'm wrong on any of these beliefs!!)  Archived actual ECMWF output is still pay (see the bottom option on &lt;a href=&quot;http://www.ecmwf.int/en/forecasts/accessing-forecasts/licences-available&quot; rel=&quot;nofollow noreferrer&quot;&gt;the license page&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I worked with ECM for a few years while producing content at &lt;a href=&quot;https://www.stormvistawxmodels.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;StormVistaWxModels&lt;/a&gt; and definitely indeed found most things with them to be quite a challenge, limitation, and pity!  At the time it was fairly abstruse to find what you needed or communicate with them, though it appears to have improved some.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-03-22T15:51:54.320" LastActivityDate="2017-03-22T15:51:54.320" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9953" PostTypeId="2" ParentId="9905" CreationDate="2017-03-22T12:35:15.403" Score="1" Body="&lt;p&gt;&lt;strong&gt;how large would the leaks have to be to counteract the positive effects?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Trying a ballpark estimate ... biogas replaces natural gas. For simplicity let's assume the replacement is 1:1, one mole of methane from biogas* replaces one mole of natural gas. This also means that one mole of biomethane &quot;saves&quot; one mole of CO2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Methane is about 25 times more intensive in terms of cliamte change than CO2. So if 100/25 = 4% leaks, the positive effect would be offset.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The factors influencing gas leakage, from biggest to smallest influence (this is mostly from memory):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Retention time of substrate in gas tight system - depending on retention time in the digesters, the digestate could still have 10% or so of it's total biogas potential, when the digestate storage is open and the HRT is short. One of the later iterations of the German rennewable energy laws specifies 150 days retention time in the gas tight system for this reason &amp;amp; I think this is reasonable for many substrates.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Leaking foil roofs - foil roofs are common on large tanks, especially the connection foil roof/digester is a common point for leakage. &lt;a href=&quot;https://publikationen.sachsen.de/bdb/artikel/15246/documents/18428&quot; rel=&quot;nofollow noreferrer&quot;&gt;This study found leakage rates from plants&lt;/a&gt; between 0 and 20 Nm³/h (median 5-10 Nm³/h), size of plants was not given but probably around 500 Nm³/h biogas production. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Methane slip - I don't have numbers to go by, but I think 0.5-1% of gas slip (unburnt gas in the exhaust) in IC motors is common. This regardless of wether you burn natural gas or biogas, AFAIK.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Manure storage - some wastes will ferment on their own, esp. manure.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Everything else - IMO the art of building gas pipes etc. is pretty well developed, if proper procedures are followed and proper materials used leakages from pipes should be neglible. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In summary, the methane loss of biogas plants may well be above the 4% cutoff point I mentioned above, or well below, depending on plant design and quality of building.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, as you pointed out in comments to your question, you need to also look at what would happen to the feedstock without biogasification. Manure would ferment (but not as completely) in an open pit and emit gasses. Municipal wastes would be either incinerated (likely with additional fuel because of the high moisture content), composted or landfilled (landfilled wastes also ferment and produce biogas, if this goes to the atmosphere, is flared or used productivly depends on the site). I have worked in landfill supervision and design of biogas plants.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At this point, I lack good numbers to really compare biogasification to other disposal paths. Having worked in landfill supervision and design of biogas plants, I have more trust in a properly designed biogas plant to keep methane out of the atmosphere than in a typically, well maintained landfill. But I'm sure you can find shoddy biogas plants that leak, for the same amount of input, worse than some landfills!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Likewise, &lt;a href=&quot;https://sustainability.stackexchange.com/questions/4772/co-firing-fossil-fuels-use-in-waste-incineration&quot;&gt;I'm still looking for hard numbers of fuel usage for incineration of biowastes&lt;/a&gt;, so I can't offer a good comparison here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So IMO, while biogas from energy crops is highly questionable, biogasification of wastes is a net benefit if done properly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*biogas is anything between 50 and 70% methane, the rest CO2 and traces.&lt;/p&gt;&#xA;" OwnerUserId="117" LastEditorUserId="-1" LastEditDate="2017-04-13T12:49:28.317" LastActivityDate="2017-03-22T12:35:15.403" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9954" PostTypeId="1" CreationDate="2017-03-22T18:34:18.927" Score="4" ViewCount="132" Body="&lt;p&gt;I particularly like the classical energy budget diagrams like that produced by &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/2008BAMS2634.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Trenberth et al in 2009&lt;/a&gt;. They are simple to understand and show all the various heat transfer mechanisms operating on the earth and its atmosphere. These diagrams are of course showing the &quot;average&quot; over the 2 primary cycles which affect heat transfer in the real world, i.e. the day/night cycle and the winter/summer cycle. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has anyone produced the same type of diagrams which show separately the heat transfers for day and for night and also the corresponding ones highlighting the differences in values for winter and summer? &lt;/p&gt;&#xA;" OwnerUserId="7733" LastEditorUserId="2536" LastEditDate="2017-06-04T11:45:54.923" LastActivityDate="2017-06-04T11:45:54.923" Title="Are there any energy budget diagram showing separate day/night and summer/winter values?" Tags="|climate|climate-change|visualization|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="9955" PostTypeId="2" ParentId="5440" CreationDate="2017-03-23T00:57:18.717" Score="0" Body="&lt;p&gt;I have got a barometer in my hall (it's supposed to predict the weather). Sure does move about a lot. You know that of course. So the answer to your question is &quot;YES&quot; , in fact any change in the composition of a gas mixture is likely to change its pressure (other things being equal), but the effect will be small as the other 999,600 ppm of other stuff has a rather bigger effect BUT even if the effect was a 1 or 2% change I doubt you could confirm it by measurement as the normal variation in barometric pressure day to day and hour to hour will rather swamp it.&lt;/p&gt;&#xA;" OwnerUserId="7733" LastActivityDate="2017-03-23T00:57:18.717" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9956" PostTypeId="1" CreationDate="2017-03-23T05:02:48.033" Score="0" ViewCount="4604" Body="&lt;h2&gt;Description&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Floods and mudslides are both occurrences, which can be &lt;strong&gt;very destructive.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Question&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(Hopefully after the edit the question is more clear)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;&lt;strong&gt;What is the difference between a flood and a mudslide?&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7538" LastEditorUserId="6298" LastEditDate="2018-05-22T05:58:13.517" LastActivityDate="2018-05-22T05:58:13.517" Title="What is the difference between a flood and a mudslide?" Tags="|geology|natural-disasters|flooding|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9957" PostTypeId="2" ParentId="9956" CreationDate="2017-03-23T07:48:13.230" Score="7" Body="&lt;p&gt;A &lt;a href=&quot;https://en.wikipedia.org/wiki/Flood&quot; rel=&quot;noreferrer&quot;&gt;flood&lt;/a&gt; occurs when land that is normally dry is covered by water. The source of the flood water is generally from bodies of water, such as: rivers, lakes, dams and even the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rivers can flood, when:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the flow rate exceeds the capacity of the river channel&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Similarly, excess water run-off during heavy rain can cause floods when the water cannot drain away quickly enough.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Flooding is the act of flood water accumulating in a area that is being flooded.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To understand &lt;a href=&quot;http://www.bepreparedcalifornia.ca.gov/BeInformed/NaturalDisasters/Pages/LandslidesandMudslides.aspx&quot; rel=&quot;noreferrer&quot;&gt;mudslides&lt;/a&gt; you need to know what a landslide is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A landslide is when a quantity of rock slides down a slope. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A &lt;a href=&quot;https://en.wikipedia.org/wiki/Mudflow&quot; rel=&quot;noreferrer&quot;&gt;mudslide&lt;/a&gt; is similar to a landslide. The only difference being the type of material that is moving. With landslides, the material moving is generally composed of rock and maybe some soil. In mudslides, the material being moved is loose, finer grained material such as mud and clay. &lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-03-23T07:48:13.230" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9958" PostTypeId="2" ParentId="8838" CreationDate="2017-03-23T08:13:00.600" Score="-4" Body="&lt;p&gt;I like this question as it makes you think about lots of things. Answering the question specifically gives me, based on my own somewhat incomplete knowledge of human history, the answer: Not really, no specific examples of human catastrophe from warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So now we wonder why.Clearly the concept of an average global temperature (as used in discussing climate change) is a mathematical construct and does not represent a temperature where all people live , to be crude about it. The earth has poles (very cold) and equator (very hot). Humans tend to live in the bits in between. If climate changed gradually we would expect humans to move gradually further north or further south if it started to become uncomfortable or difficult. However we know from personal experience that we go on holiday where it is hotter, often much hotter, and cope very well for a fortnight even for a temperature increase of 20 degrees C. When it get really cold however, say in a harsh winter in England, and the temperature is sub zero, maybe -15 degress C, for a few days we find it much harder to cope.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe if we plot a graph of &quot;human copeability&quot;  v local environment temperature change it will be nowhere near linear. The other factor that comes to  mind is that cooling produces ice and snow which are physical things you need to deal with, e.g. effect on transport and also can be a tipping point for certain crops e.g. frost damage. So just a few unusually cold days/nights could destroy a crop wheras it takes a more prolonged excess of heat to damage crops, again probably a non linear graph.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Overall I expect we may find human populations that live in the colder parts of the planet are living much nearer to the &quot;edge&quot; of survivabilty compared to those living in the hottest parts of the planet. I seem to remember reading somewhere that humans originated in Africa (a hot bit) so our &quot;design&quot; is for near equator temperatures +- (some range).       &lt;/p&gt;&#xA;" OwnerUserId="7733" LastActivityDate="2017-03-23T08:13:00.600" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9960" PostTypeId="1" AcceptedAnswerId="9961" CreationDate="2017-03-23T13:40:50.523" Score="8" ViewCount="430" Body="&lt;p&gt;This question was originally posted on Physics SE, (now deleted) but I think this community is a better fit. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This article &lt;a href=&quot;http://www.bbc.com/news/science-environment-39351843&quot; rel=&quot;noreferrer&quot;&gt;&quot;New&quot; type of Clouds&lt;/a&gt;, reports that a revision to the  &lt;a href=&quot;https://en.wikipedia.org/wiki/International_Cloud_Atlas&quot; rel=&quot;noreferrer&quot;&gt;International Cloud Atlas&lt;/a&gt; will include 12 extra examples of cloud shapes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6WdzB.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6WdzB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This time around 12 new terms have been added. The best known of these is asperitas, meaning rough-like in Latin, as the clouds can look like the tossing of the waves at sea when viewed from below.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I am aware that these are &lt;strong&gt;not&lt;/strong&gt; new cloud types per se, rather the article is referring to a reclassification system. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These cloud types in all probability have been in existence for a long time, and it is due to the increasing use of cameras on smartphones that has contributed to their new prominence in the Atlas. The article I cite above includes references to the well known jet contrails, but does not ascribe any more significance to these cloud classifications than that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gsEYv.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gsEYv.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In terms of the way the WMO classifies clouds, they have also added one new &quot;species&quot; - the volutus, or roll-cloud, a low horizontal tube-shaped cloud mass that appears to roll about a horizontal axis. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My question, promoted by this reclassification of &lt;strong&gt;existing&lt;/strong&gt; cloud types,  is: could new cloud types be associated with human activity and, (a  tenuous connection I admit), could we use the amount of these putative new cloud types to act as a crude marker of our impact on the current atmospheric environment?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would stress that the website of the &lt;a href=&quot;https://public.wmo.int/en/media/news/international-cloud-atlas&quot; rel=&quot;noreferrer&quot;&gt;International Cloud Atlas&lt;/a&gt; makes no obvious, at least on initial reading, link to my question above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am aware of the  &lt;a href=&quot;http://news.psu.edu/story/361041/2015/06/18/research/jet-contrails-affect-surface-temperatures&quot; rel=&quot;noreferrer&quot;&gt;Penn State Jet Trail Research&lt;/a&gt; regarding jet trails, in particular their absence from the atmosphere following the 9/11 attacks and subsequent temporary flight ban.&lt;/p&gt;&#xA;" OwnerUserId="7759" LastActivityDate="2017-03-24T13:31:44.420" Title="&quot;New&quot; cloud types: Can they be used as markers for climate change observations?" Tags="|climate-change|clouds|" AnswerCount="1" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="9961" PostTypeId="2" ParentId="9960" CreationDate="2017-03-24T13:31:44.420" Score="2" Body="&lt;p&gt;My answer is no. The reclassification of clouds is not affected by climate change. It is more of our understanding of how they work, formation mechanisms, etc. Cloud classification can generally be broken down into altitude and shape (cirrus-type, cumulus-type, and stratus-type). The subtypes of those describe the behavior, and may be combinations of types (such as cirrostratus, pyrocumulus and cumulonimbus). There are other types, such as the new asperitas cloud (formed by gravity waves), the Kelvin-Helmholtz instability cloud (formed by the Kelvin-Helmholtz instability), contrails (formed by jet exhaust), fog (formed by either advection or radiation), etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is not to say that clouds don't affect climate. For example, cirrus clouds, and other high clouds, are optically thick, preventing the low temperature from dropping. It has been debated what the net effect clouds have on the environment, newer research seems to indicate net warming (see latest IPCC report), despite the traditional thought being cooling. Being that water vapor is a greenhouse gas with generally greater concentrations than the famed CO$_2$, it is extremely important to consider in climate discussion.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-03-24T13:31:44.420" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9962" PostTypeId="1" CreationDate="2017-03-24T15:33:21.047" Score="3" ViewCount="159" Body="&lt;p&gt;&lt;em&gt;I originally posted this over on &lt;a href=&quot;https://sustainability.meta.stackexchange.com/q/269/3379&quot;&gt;Sustainability.SE&lt;/a&gt; and someone suggested I try asking over here.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone recommend a book or books, intended for a non-scientific audience, which covers some (or all) of these elements?&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Basic science of global warming&lt;/li&gt;&#xA;&lt;li&gt;Evidence from ice cores, temp readings, ocean acidity, etc&lt;/li&gt;&#xA;&lt;li&gt;Climate modeling and simulations&lt;/li&gt;&#xA;&lt;li&gt;Projected scenarios and impacts&lt;/li&gt;&#xA;&lt;li&gt;Actions that individuals can take to reduce impact, ranging from simple (eat less meat, adjust thermostat) to more demanding (switch to bike commute, buy electric car)&lt;/li&gt;&#xA;&lt;li&gt;Corporate actions (policy setting for organizations and companies, what to ask political candidates about, etc)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I am looking for something that emphasizes clarity, an engaging writing style, and a positive attitude about the possibility of averting crisis. After reading this book someone should feel that they have a good general understanding of what causes global warming, and know specific actions they can take which will have a measurable impact.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The intended audience for this book would be people who know (or suspect) that climate change is a big deal, and know they should do something about it, but don't feel personally invested in the problem or solutions.&lt;/p&gt;&#xA;" OwnerUserId="7741" LastActivityDate="2017-10-25T11:53:14.753" Title="Educational book on science of climate change with action items?" Tags="|climate-change|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9963" PostTypeId="2" ParentId="2290" CreationDate="2017-03-25T03:10:21.930" Score="2" Body="&lt;p&gt;Determining an uplift rate for rocks is not easy, but certain techniques will produce far more reliable results than others. There are also qualitative techniques that provide estimates so rough as to be almost useless. For example, this technique, from the 'answer', above:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;So you know this used to be at the sea floor, let's say 300 meters&#xA;below the water, but now it's 2000 meters up in the sky. So it had to&#xA;rise 2300 meters in 5 million years. You can calculate the average&#xA;uplift rate from that.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;...fails to account for the time this sediment spent lithifying, or &amp;quot;turning into stone&amp;quot; which would certainly have involved deep burial for some unknown time, at an unknown depth, yielding an upper, or lower bound on no more than a wild guess.&lt;/p&gt;&#xA;&lt;p&gt;Uplift rates of basement rocks (mountain cores) are best quantified using &amp;quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Fission_track_dating&quot; rel=&quot;nofollow noreferrer&quot;&gt;fission track dating&lt;/a&gt;&amp;quot;; a thermochronometry technique whereby the helium track lengths, produced by the radioactive decay of uranium into thorium, are analyzed. The technique depends on careful selection of appropriate mineral crystals, within the host rock, containing radioactive elements. Even this technique requires understanding an uncertain history of annealing temperatures. For example, in this paper:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;&lt;a href=&quot;http://www.geol.ucsb.edu/faculty/burbank/Site/Publications_files/Sobel%20Tien%20Shan%20Tectonics%202006.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Exhumation of basement-cored uplifts: Example of the Kyrgyz Range quantified with apatite fission track thermochronology&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;the following figure illustrates the complexity of the problem:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/JyVzq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JyVzq.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JyVzq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Schematic illustration of the affect of differing total annealing temperatures (Ta) on complex cooling paths. The four vertical elevation profiles represent a sequence of exhumation (cooling) and burial (reheating) events. (top) Evolving temperature history and (bottom) distribution of apatite fission&#xA;track ages in a vertical profile at the corresponding time step. Each profile shows the cooling path of apatites that are more (solid line) and less (dashed line) resistant to annealing. The base of the partial annealing zone (PAZ) for each type of apatite is considered to be the respective Ta. Exhumation and&#xA;burial events are (unrealistically) depicted as instantaneous for clarity. The geothermal gradient is assumed to remain constant and advection of isotherms is neglected for simplicity.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The above paper is an excellent analysis of the history of uplift of the Kyrgyz mountains, in which constraints were made on the age of uplifting as the range grew laterally. Mountains don't just grow vertically!&lt;/p&gt;&#xA;" OwnerUserId="7333" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-03-25T03:10:21.930" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9964" PostTypeId="2" ParentId="606" CreationDate="2017-03-25T19:34:17.377" Score="2" Body="&lt;p&gt;Assuming that your observation hasn't mistakenly included temporary snowfields, glaciers, like other forms of water, will take the path of least resistance and will certainly be directed by local geology. Weak strata, faulting type and orientation, and jointing all work to dictate erosional patterns up to the point that they erase them entirely. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suspect that your observation of &quot;glaciers&quot; only on the east side of these mountains is merely an artifact of (very) local geological structure. In fact, based on this recently constructed glacier flow map of southern Norway 13,000 YBP, one would be hard pressed to claim an overall preferential pattern of glacier position and movement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aDTnf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aDTnf.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-03-25T19:34:17.377" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9966" PostTypeId="1" AcceptedAnswerId="9968" CreationDate="2017-03-26T09:32:48.510" Score="8" ViewCount="706" Body="&lt;p&gt;The news article &lt;a href=&quot;http://www.bbc.com/news/science-environment-39394583&quot; rel=&quot;noreferrer&quot;&gt;Impact crater linked to Martian tsunamis&lt;/a&gt; describes results of numerical calculations which address the possibility that a giant martian tsunami triggered by an impact has left recognizable features on the martian landscape. The research is published in the Journal of Geophysical Research - Planets, but as of this moment the DOI link there doesn't seem to work. However, it seems to be:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Costard et al. 2017, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2016JE005230/full&quot; rel=&quot;noreferrer&quot;&gt;Modeling tsunami propagation and the emplacement of thumbprint terrain in an early Mars ocean&lt;/a&gt;, DOI: 10.1002/2016JE005230, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;ABSTRACT:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The identification of lobate debris deposits in Arabia Terra, along the proposed paleoshoreline of a former northern ocean, has renewed questions about the existence and stability of ocean-sized body of water in the early geologic history of Mars. The potential occurrence of impact-generated tsunamis in a northern ocean was investigated by comparing the geomorphologic characteristics of the Martian deposits with the predictions of well-validated terrestrial models (scaled to Mars) of tsunami wave height, propagation direction, runup elevation, and distance for three potential sea levels. Our modeling suggests several potential impact craters ~30–50 km in diameter as the source of the tsunami events. Within the complex topography of flat-floored valleys and plateaus along the dichotomy boundary, the interference of the multiple reflected and refracted waves that are observed in the simulation may explain the origin of the arcuate pattern that characterizes the thumbprint terrain.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Also see &lt;a href=&quot;http://agupubs.onlinelibrary.wiley.com/hub/article/10.1002/2016JE005230/editor-highlight/&quot; rel=&quot;noreferrer&quot;&gt;Editor Highlight&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can not access the article yet, but the BBC interview with Costard leaves me puzzled about the speed of tsunamis:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Two successive waves were formed during the event, says François Costard.&#xA;  &quot;It was a really large-scale, high speed tsunami. At the very beginning, a crater of 70km in diameter was created by the impact. This expelled a huge volume of water, with wave propagation at &lt;strong&gt;60m/second&lt;/strong&gt;,&quot; he explained. (emphasis added)&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&quot;The initial wave was about 300m in height. After just a few hours, that tsunami wave reached the palaeo-shoreline located at a few hundred km from the impact crater.&quot;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;This gigantic wave washed over hills and plateaus and through valleys, leaving behind the lobate flow deposits.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&quot;Finally... due to the Martian ocean filling in that crater, which produced a kind of rebound, there was a second wave propagation,&quot; Dr Costard added.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;60m/s is 216 km/h, and this is consistent with a few hundred km in a few hours also mentioned.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; If I just google the speed of a Tsunami on Earth, I see 800 km/h. The surface gravity on Mars is about 3.71 m/s^2, or about a factor of 2.6 lower than that of Earth. Does this explain the factor of 4 slower speed of the Tsunami wave quantitatively?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; &quot;The thumbprint terrains probably formed when two sets of tsunami waves interacted.&quot; from &lt;a href=&quot;http://www.bbc.com/news/science-environment-39394583&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/X3ni1.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/X3ni1.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2017-03-26T09:42:48.290" LastActivityDate="2017-03-26T11:02:37.887" Title="Why would a Martian tsunami travel at only 200 km/hour, four times slower than on Earth?" Tags="|wave-modeling|tsunami|impacts|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9968" PostTypeId="2" ParentId="9966" CreationDate="2017-03-26T11:02:37.887" Score="11" Body="&lt;p&gt;The linked paper does numerical modelling of a hypothetical tsunami and predicts speeds between 60 m/s (at its point of origin) and 30 m/s (nearer to shore). We can try a back-of-an-envelope approximation to see if we get close, and to understand why the speed would be so much lower than on Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A tsunami behaves as a gravity wave with a very long wavelength. In shallow water (and pretty much anywhere in Earth's oceans counts as shallow water for such a long wave), the speed at which it moves is approximated by&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$V = \sqrt{gD}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $V$ is the wave's speed, $D$ is the depth, and $g$ is the acceleration due to gravity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On Earth, $g = 9.81$ m/s&lt;sup&gt;2&lt;/sup&gt; and, in the deep ocean, we might assume a depth of 4 km and obtain a speed of 198 m/s, or 713 kph.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's try this for Mars. As you've identified, the acceleration due to gravity on Mars is about 3.8 m/s&lt;sup&gt;2&lt;/sup&gt;, and the linked paper gives assumed depths of the ocean on Mars as between 100 and 1200 m (forgive me if this is not quite right - I've only skimmed the paper, and these figures come from Table 1). Let's assume a 1000 m depth, since the highest speeds will be found in deep water:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ V = \sqrt{ 3.8 \times 1000 } = 61.6\ \textrm{m/s} $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;which is close enough to their value for comfort. So a tsunami on the Mars described here would be much slower than on Earth due to the weaker force of gravity and the shallower depth of the ocean.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2017-03-26T11:02:37.887" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9970" PostTypeId="1" AcceptedAnswerId="9971" CreationDate="2017-03-27T09:01:28.580" Score="8" ViewCount="1399" Body="&lt;p&gt;To calculate the average daily temperatures, do meteo professionals still use the Mannheim procedure with twice weighted measurement in the evening?&lt;br /&gt; (It could be obsolete by automated weather stations.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If so, does DST affect the daily average by getting that measurement one hour earlier?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not asking if that invalidates the results, just whether there is a measurable impact.&lt;/p&gt;&#xA;" OwnerUserId="7774" LastEditorUserId="595" LastEditDate="2017-03-27T09:53:28.313" LastActivityDate="2017-03-27T15:30:01.397" Title="Are average daily temperatures affected by DST?" Tags="|temperature|measurements|" AnswerCount="1" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9971" PostTypeId="2" ParentId="9970" CreationDate="2017-03-27T09:39:50.513" Score="11" Body="&lt;p&gt;They compensate for DST.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is, for any daily measurement, they use the same universal time every day of the year.  If they take a measurement at 7:00 local time in summer, they will take the same measurement at 6:00 in winter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(So if you do see a DST effect in the data, that would be due to traffic and other local anthropogenic effects shifting by an hour relative to the time of measurement!  Perhaps due to urban heat island effect, or forcing by anthropogenic aerosols from traffic or industry.)&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2017-03-27T15:30:01.397" LastActivityDate="2017-03-27T15:30:01.397" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9973" PostTypeId="2" ParentId="4511" CreationDate="2017-03-27T14:10:51.250" Score="5" Body="&lt;p&gt;The hours are not independent of each other. For example, suppose there's a chance of a hurricane hitting the area.  If it hits, it will be rainy every hour of the day.  If it misses, it will not rain at all.  On the other hand, thunderstorms are more independent: getting one at 2pm doesn't increase the chance of getting another one at 4pm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To the extent that the hours are independent you can calculate the daily probability as you described; however, it's more likely that they are dependent on each other, especially in winter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.insidescience.org/news/how-do-daily-weather-forecasts-relate-hourly-forecasts-it-depends&quot; rel=&quot;noreferrer&quot;&gt;https://www.insidescience.org/news/how-do-daily-weather-forecasts-relate-hourly-forecasts-it-depends&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7778" LastActivityDate="2017-03-27T14:10:51.250" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9974" PostTypeId="1" AcceptedAnswerId="13276" CreationDate="2017-03-27T16:46:27.490" Score="7" ViewCount="431" Body="&lt;p&gt;I know that the von Kármán constant ($k\approx0.4$) is useful in turbulence modeling. Something that bothers me is my lack of understanding where $k$ comes from or the physical meaning behind it. If $k$ is mainly used as a proportionality in the log-wind profile, why is it within the formulation of the Monin-Obukhov length? What is the physical meaning behind $k$? Is it a universal value (i.e. valid on extraterrestrial planets)? Why is $k$ considered important enough to be eponymous, while I see $\frac{1}{k}$ more often in formulations than $k$?&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="111" LastEditDate="2017-03-27T21:13:08.090" LastActivityDate="2018-02-03T07:47:58.760" Title="What is the physical meaning of the von Kármán constant?" Tags="|turbulence|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9975" PostTypeId="1" CreationDate="2017-03-28T01:37:17.377" Score="8" ViewCount="152" Body="&lt;p&gt;Inspired by the title to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9970/are-average-daily-temperatures-affected-by-dst&quot;&gt;this question&lt;/a&gt;, is there a shift in average daily temperatures caused by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Daylight_saving_time&quot; rel=&quot;nofollow noreferrer&quot;&gt;DST&lt;/a&gt; change in human activities?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can picture any number of mechanisms by which a shift could happen (eg. more cars driving past the thermometer at the time the measurements are taken), so has such a shift been found?&lt;/p&gt;&#xA;" OwnerUserId="2643" LastEditorUserId="2536" LastEditDate="2017-05-18T11:38:55.690" LastActivityDate="2017-11-14T14:28:55.923" Title="Do humans cause a DST-related shift in average daily temperatures?" Tags="|temperature|measurements|human-influence|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="9976" PostTypeId="1" AcceptedAnswerId="9999" CreationDate="2017-03-28T03:36:54.163" Score="3" ViewCount="171" Body="&lt;p&gt;The MIT Technology Review news item &lt;a href=&quot;https://www.technologyreview.com/s/603974/harvard-scientists-moving-ahead-on-plans-for-atmospheric-geoengineering-experiments/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Harvard Scientists Moving Ahead on Plans for Atmospheric Geoengineering Experiments&lt;/a&gt; discusses a proposed experiment to study in a carefully controlled way the reflectivity induced by various kinds of particles released into the stratosphere. The underlying idea being explored is that increased atmospheric reflectance could partially offset warming effects due to greenhouse gases.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Sometime next year, Harvard professors &lt;a href=&quot;https://www.technologyreview.com/s/603974/harvard-scientists-moving-ahead-on-plans-for-atmospheric-geoengineering-experiments/&quot; rel=&quot;nofollow noreferrer&quot;&gt;David Keith&lt;/a&gt; and Frank Keutsch hope to launch a high-altitude balloon, tethered to a gondola equipped with propellers and sensors, from a site in Tucson, Arizona. After initial engineering tests, the “StratoCruiser” would spray a fine mist of materials such as &lt;strong&gt;sulfur dioxide, alumina, or calcium carbonate&lt;/strong&gt; into the stratosphere. The sensors would then measure the reflectivity of the particles, the degree to which they disperse or coalesce, and the way they interact with other compounds in the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;The researchers first proposed these balloon experiments in a &lt;a href=&quot;http://rsta.royalsocietypublishing.org/content/372/2031/20140059&quot; rel=&quot;nofollow noreferrer&quot;&gt;2014 paper&lt;/a&gt;. But at a geoengineering conference in Washington, D.C., on Friday, Keith said they have begun engineering design work with Arizona test balloon company World View Enterprises. They’ve also started discussions about the appropriate governance structure for such an experiment, and they plan to set up an independent body to review their proposals.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is an effort to explore how best to do a small, controlled test and how to establish proper guidelines. This type of atmospheric experiment is very different than the long established practice of &lt;a href=&quot;https://en.wikipedia.org/wiki/Cloud_seeding&quot; rel=&quot;nofollow noreferrer&quot;&gt;cloud seeding&lt;/a&gt; for rain, so this thoughtful approach is taken.&lt;/p&gt;&#xA;&lt;p&gt;A short review of the background concept and associated issues can be found in the &lt;a href=&quot;http://www.theverge.com/2017/3/24/15053204/ice-balloon-geoengineering-climate-change-world-view-david-keith&quot; rel=&quot;nofollow noreferrer&quot;&gt;video shown in this article&lt;/a&gt;, after the first minute or so it gets more serious.&lt;/p&gt;&#xA;&lt;p&gt;While Alumina (Al2O3) and calcium carbonate (CaCO3) might be in the form of solid particles for such an experiment, and particle size can be engineered to various controlled size distributions ahead of time, sulfur dioxide (SO2) is a gas at STP. At one atmosphere of pressure, it would become a liquid &lt;a href=&quot;https://en.wikipedia.org/wiki/Sulfur_dioxide&quot; rel=&quot;nofollow noreferrer&quot;&gt;at about -10C&lt;/a&gt;. Would the plan be to spray or atomize liquid SO2 at the low ambient temperature at altitude?&lt;/p&gt;&#xA;&lt;p&gt;If I understand correctly, SO2's mechanism would be to 'chemically scavenge'  water vapor from the air, forming reflective droplets of sulfuric acid. Would the alumina and calcium carbonate also seed water droplet formation as their reflective mechanism, or would only the particles themselves be reflective?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-03-30T10:34:35.150" Title="How would this experiment's different particle types produce atmospheric reflectivity?" Tags="|climate-change|atmospheric-chemistry|atmospheric-radiation|upper-atmosphere|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9977" PostTypeId="1" CreationDate="2017-03-28T05:30:12.097" Score="10" ViewCount="9843" Body="&lt;p&gt;In Tibetan Plateau, about 4600m elevation, If &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Manasarovar&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Manasarovar&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Rakshastal&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Rakshastal&lt;/a&gt; (&quot;lake of the demon&quot; ) used to be the same lake, but due to the tectonic activity now they are separated to two by small hills, how come Lake Manasarovar is a fresh-water lake while Lake Rakshastal is a salt-water lake?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Before they were separated, was the overall old lake a fresh-water lake or a salt-water lake?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EmpDP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EmpDP.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is that just because Lake Rakshastal is in the Endorheic basin and Lake Manasarovar is not within the Endorheic basin?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, Lake Manasarovar overflows into lake Rakshastal which is a salt-water endorheic lake. These lakes used to be part of the Sutlej basin and were separated due to tectonic activity.&lt;/p&gt;&#xA;" OwnerUserId="7787" LastEditorUserId="7787" LastEditDate="2017-03-29T00:03:22.753" LastActivityDate="2020-03-21T05:27:41.647" Title="Lake Manasarovar v.s. Lake Rakshastal: fresh-water v.s. salt-water" Tags="|plate-tectonics|water|mountains|salinity|tibetan-plateau|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9978" PostTypeId="1" AcceptedAnswerId="15946" CreationDate="2017-03-28T07:17:46.177" Score="11" ViewCount="2096" Body="&lt;p&gt;I'm a big fan of &lt;a href=&quot;https://en.wikipedia.org/wiki/Vsauce&quot; rel=&quot;noreferrer&quot;&gt;Vsauce&lt;/a&gt; and the video &lt;a href=&quot;https://www.youtube.com/watch?v=IJhgZBn-LHg&quot; rel=&quot;noreferrer&quot;&gt;How Earth Moves&lt;/a&gt; is just one example of science related to the Earth available there (there's plenty more).&lt;/p&gt;&#xA;&lt;p&gt;But the statement in &lt;a href=&quot;https://youtu.be/YMTLkDrcr28?t=99&quot; rel=&quot;noreferrer&quot;&gt;this video starting at &lt;code&gt;01:39&lt;/code&gt;&lt;/a&gt; strikes me as a little surprising.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;You know how a figure skater, spinning in place, can slow down their (rotational) speed by extending their arms out; by moving some of their body mass away from the middle of their body? Well the same thing can happen to Earth.&lt;/p&gt;&#xA;&lt;p&gt;The Three Gorges Dam did exactly what a figure skater does when they move their arms away from their center. It transferred &lt;strong&gt;thirty nine trillion kilograms of water one hundred and seventy five meters above sea level&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;NASA calculated that that massive amount of water moved, caused Earth’s rotation to slow down, so that &lt;strong&gt;every day&lt;/strong&gt; of your life since that dam was finished, &lt;strong&gt;has been longer by 0.06 microseconds&lt;/strong&gt;. (emphasis added)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;If I calculated correctly, that would be a &amp;quot;slip&amp;quot; of about 1 centimeter per year at the equator.&lt;/p&gt;&#xA;&lt;p&gt;There are many causes of change to the Earth's distribution of mass, it's moment of inertia, and therefore the length of a day. Tidal forces from the Moon can contribute substantially to changes in Earth's rotation as well, and there could be short term geological effects as well.&lt;/p&gt;&#xA;&lt;p&gt;Is this &lt;em&gt;roughly 0.06 microsecond/day shift&lt;/em&gt; well below the &amp;quot;noise&amp;quot; level, where in this case I'm using &amp;quot;noise&amp;quot; to refer to effects that are smaller than the error that can be modeled? So for example exchanges between sea ice and sea water can be measured and modeled to some level of accuracy, and the Moon's tidal effects &lt;a href=&quot;https://physics.stackexchange.com/q/251700/83380&quot;&gt;can be measured and modeled&lt;/a&gt; to great precision, so even if the Three Gorges Dam effect turns out to be small compared to those, it could still be detected as long as its effect is larger than the error that those effects can be accurately calculated.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; Screen shots from the Vsauce YouTube video &lt;a href=&quot;https://youtu.be/YMTLkDrcr28?t=99&quot; rel=&quot;noreferrer&quot;&gt;Water.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/uJPj0.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uJPj0.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DuWpS.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DuWpS.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2022-08-09T12:00:36.693" Title="Was the filling of the Three Gorges Dam's impact on the Earth's rotation rate detectable?" Tags="|water|earth-rotation|dams|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9979" PostTypeId="2" ParentId="7370" CreationDate="2017-03-28T07:39:01.840" Score="1" Body="&lt;p&gt;This is to a certain degree possible. See this article:&#xA;&lt;a href=&quot;https://dl.sciencesocieties.org/publications/sssaj/abstracts/77/6/2173&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://dl.sciencesocieties.org/publications/sssaj/abstracts/77/6/2173&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="364" LastActivityDate="2017-03-28T07:39:01.840" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9984" PostTypeId="1" CreationDate="2017-03-28T17:25:24.537" Score="2" ViewCount="2494" Body="&lt;p&gt;Given a data set which consists of pairs of longitudes and latitudes, is it possible to determine an estimate of the ocean bottom depth at that point?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can find maps of estimated sea depths online (e.g. &lt;a href=&quot;https://maps.ngdc.noaa.gov/viewers/bathymetry/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://maps.ngdc.noaa.gov/viewers/bathymetry/&lt;/a&gt;), but I am not sure how to go about it extracting the data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I could look at every single point, and look at the map and find the depth level, but I have &gt; 1000 points so ....&lt;/p&gt;&#xA;" OwnerUserId="7791" LastEditorUserId="18081" LastEditDate="2022-08-04T08:37:11.217" LastActivityDate="2022-08-04T08:37:11.217" Title="How to determine ocean bottom depth for a data set consisting of longitude and latitude?" Tags="|oceanography|sea-level|mapping|bathymetry|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9985" PostTypeId="2" ParentId="9977" CreationDate="2017-03-28T18:41:25.273" Score="5" Body="&lt;p&gt;You pretty much answered the question yourself.  Lake Rakshastal, along with most of the lakes along the Tibetan plateau is, indeed an endorheic lake.  The important meaning of that term is that there is no outflow from that basin.  Water evaporates, but as with any evaporative process, the minerals in the water stay behind and become more concentrated.  Since Lake Manasrovar flows into Lake Rakshastal, the water that leaves takes the minerals in contains with it, leading to a much lesser concentration left behind as new water flows in, and, most importantly, out of that lake.&lt;/p&gt;&#xA;" OwnerUserId="6665" LastActivityDate="2017-03-28T18:41:25.273" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9986" PostTypeId="2" ParentId="9984" CreationDate="2017-03-28T18:55:03.847" Score="2" Body="&lt;p&gt;The easiest products that provides ocean bathymetry (bottom depth) is the one you mentioned: &lt;a href=&quot;https://maps.ngdc.noaa.gov/viewers/bathymetry/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://maps.ngdc.noaa.gov/viewers/bathymetry/&lt;/a&gt;. It provides bathymetry data from a plethora of surveys. If you click in the map at any location, you will get a decent estimate of the depth at that point. You can also extract the surveys and data that are available for any given location. You also get DEMs and Lidar data. You can define a bounding box or a polygon (Identify tab) and it will provide the links to the original data. The original data in areas where no recent surveys are available is usually either from &lt;a href=&quot;https://www.ngdc.noaa.gov/mgg/global/global.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ETOPO&lt;/a&gt; or &lt;a href=&quot;http://www.gebco.net/data_and_products/gridded_bathymetry_data&quot; rel=&quot;nofollow noreferrer&quot;&gt;GEBCO&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are interested in a specific area you can also use a region selector directly from  &lt;a href=&quot;http://www.gebco.net/data_and_products/gridded_bathymetry_data&quot; rel=&quot;nofollow noreferrer&quot;&gt;GEBCO&lt;/a&gt; (pick a box around all your points and extract the data that way).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can also try &lt;a href=&quot;https://www.nauticalcharts.noaa.gov/mcd/enc/index.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA electronic navigational charts&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2017-03-28T19:20:19.300" LastActivityDate="2017-03-28T19:20:19.300" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9987" PostTypeId="1" CreationDate="2017-03-28T20:16:42.250" Score="5" ViewCount="335" Body="&lt;p&gt;The Puy de Dôme is an extinct volcano located pretty much smack in the middle of France. It last erupted some seven thousand years ago, which in geological terms is fairly recent - prehistoric humans might even have born witness to that eruption! What I'm wondering, though, is what drove this volcano, seeing as it is not located where tectonic plates meet? Was there a hot spot underneath central France that powered this volcano, and if so, could we witness future volcanic activity in this region?  &lt;/p&gt;&#xA;" OwnerUserId="7793" LastActivityDate="2017-03-30T18:22:26.083" Title="What drove the Puy de Dôme volcano?" Tags="|volcanology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9989" PostTypeId="1" AcceptedAnswerId="12392" CreationDate="2017-03-29T00:45:49.297" Score="5" ViewCount="11153" Body="&lt;p&gt;Are EF6 tornadoes officially recognized on the Fujita scale?&lt;/p&gt;&#xA;" OwnerUserId="7151" LastEditorUserId="18081" LastEditDate="2021-10-21T15:34:58.577" LastActivityDate="2021-10-21T15:34:58.577" Title="Are EF6 tornadoes officially recognized?" Tags="|meteorology|tornado|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="9990" PostTypeId="2" ParentId="9989" CreationDate="2017-03-29T01:07:47.253" Score="5" Body="&lt;p&gt;No. The highest is the EF5.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;https://en.wikipedia.org/wiki/Enhanced_Fujita_scale&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Enhanced_Fujita_scale&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-03-29T01:07:47.253" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="9991" PostTypeId="2" ParentId="4239" CreationDate="2017-03-29T10:25:32.460" Score="1" Body="&lt;p&gt;You can try CMORPH data set- &lt;a href=&quot;http://www.cpc.ncep.noaa.gov/products/janowiak/cmorph_description.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;CMORPH Description&lt;/a&gt;. As explained in the original reference - &lt;a href=&quot;http://ftp.cpc.ncep.noaa.gov/precip.orig/CMORPH_V1.0/REF/Joyce_et_al_2004_JHM_CMORPHP.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;CMORPH publication&lt;/a&gt; the authors obtain half hourly global precipitation estimates derived from passive microwave satellite scans and they are propagated by motion vectors derived from geostationary IR data. So these are spatially and temporally complete microwave based precipitation estimates independent of the IR temperature field. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason why it is called a &quot;MORPH&quot; is because shape and intensity of the precipitation estimates are modified during the time between two successive microwave scans by a time weighted linear interpolation scheme. The flexibility of CMORPH indicates it can enhance the value  &lt;a href=&quot;https://pmm.nasa.gov/data-access/downloads/gpm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Precipitation Mission Data&lt;/a&gt; by combining IR scans with GPM and hence increasing the temporal resolution of GPM to thirty minutes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;CMORPH can be downloaded from &lt;a href=&quot;http://from%20ftp://%20%20ftp.cpc.ncep.noaa.gov/precip/CMORPH_V1.0/CRT/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Download URL&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are only downloading via OPeNDAP you can get it from the RDA&#xA;&lt;a href=&quot;https://rda.ucar.edu/datasets/ds502.0/&quot; rel=&quot;nofollow noreferrer&quot;&gt;RDA CMORPH1 &lt;/a&gt; and &lt;a href=&quot;https://rda.ucar.edu/datasets/ds502.1/&quot; rel=&quot;nofollow noreferrer&quot;&gt;RDA CMORPH2&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2017-03-29T13:18:17.033" LastActivityDate="2017-03-29T13:18:17.033" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9992" PostTypeId="1" AcceptedAnswerId="9993" CreationDate="2017-03-29T11:25:50.877" Score="2" ViewCount="1333" Body="&lt;p&gt;The recent cyclone to impact the Queensland coast of Australia (Cyclone Debbie, Category 4) tracked towards the coast at what was reported to be a very slow speed (between 6 and 7 km/hr). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is that a particularly slow speed for a cyclone to move at, and second, what governs the speed and direction of cyclone movement? &lt;/p&gt;&#xA;" OwnerUserId="7027" LastActivityDate="2017-03-31T02:18:30.657" Title="What influences the movement (speed and direction) of tropical cyclones?" Tags="|tropical-cyclone|severe-weather|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9993" PostTypeId="2" ParentId="9992" CreationDate="2017-03-29T12:17:23.060" Score="3" Body="&lt;p&gt;Cyclones generally drift in a westerly/north westerly direction due to the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Beta_drift&quot; rel=&quot;nofollow noreferrer&quot;&gt;Beta Drift &lt;/a&gt; and &lt;a href=&quot;https://www.wunderground.com/blog/JeffMasters/the-beta-effect&quot; rel=&quot;nofollow noreferrer&quot;&gt;Beta Effect&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For atlantic hurricanes the forward speeds are summarized here by latitudinal range -&lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/G16.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Average forward speed of Atlantic Hurricanes&lt;/a&gt; and  if there is recurve(turn more northerly) they can slow down or if they cross mid latitudes they may pick up speed by interacting with mid latitude troughs. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the latitude of Midge Point, Queensland you can expect forward speeds of about 17-18 kms/hr. So this cyclone is certainly slow moving. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.thoughtco.com/what-is-a-tropical-cyclone-3443930&quot; rel=&quot;nofollow noreferrer&quot;&gt;TC forward speed&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are other factors influencing cyclone tracks which include steering winds, presence of high pressure systems,etc and more recent studies have studied the influence of SST on cyclone tracks &lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-15-0198.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Response of  cyclone tracks to SST&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From this peer reviewed reference &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2008GL036953/pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Effect of forward speed on flooding&lt;/a&gt; modeling studies reveal that increasing forward speed decreases flooded volumes while increasing peak surge&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Back to Cyclone Debbie it looks like from this blog at least &lt;a href=&quot;http://hurricanehalssb.blogspot.in/2017/03/tropical-cyclone-debbie-pounds.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cyclone Debbie Progress&lt;/a&gt; the forward speed of the cyclone is probably one of the reasons for the water to be present for more than one day and making sure storm surge occurs at the same time as the high tide. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2017-03-31T02:18:30.657" LastActivityDate="2017-03-31T02:18:30.657" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9994" PostTypeId="1" AcceptedAnswerId="10009" CreationDate="2017-03-29T15:19:35.127" Score="18" ViewCount="21597" Body="&lt;p&gt;I read somewhere in a book that mostly desert found in the western part of a continent.  So my question is that why is it so? I searched on the internet but I didn't get a reasonable answer for that.&lt;/p&gt;&#xA;" OwnerUserId="7785" LastEditorDisplayName="user12525" LastEditDate="2019-04-26T09:31:54.053" LastActivityDate="2019-04-26T09:31:54.053" Title="Why are deserts mostly located on the western side of continents?" Tags="|meteorology|geomorphology|climatology|atmospheric-circulation|" AnswerCount="2" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="9995" PostTypeId="2" ParentId="9994" CreationDate="2017-03-29T18:28:04.030" Score="8" Body="&lt;p&gt;Because of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Coriolis_force&quot; rel=&quot;nofollow noreferrer&quot;&gt;Coriolis Effect&lt;/a&gt;, the prevailing winds on the earth between about the Tropic of Capricorn and the Tropic of Cancer go from the East to the West (knows as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Trade_winds&quot; rel=&quot;nofollow noreferrer&quot;&gt;Trade Winds&lt;/a&gt;). To get to the west coast of a continent within those latitudes, an air mass blowing from above an ocean must cross the entire continent. Along the way, the air mass causes precipitation (rain, snow, etc.) and loses water so by the time it reaches the west coast the air tends to be very dry and average annual precipitation will be very low.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Rain_shadow&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rain shadow&lt;/a&gt;&quot; is a related effect in which the lee side of mountain ranges are dry because air masses experience orographic rainfall when they encounter the mountain range. This causes the Atacama desert to the west of the Andes, and the Mojave to the east of the Sierra Nevada. Note that the Mojave is east of the Sierra Nevada rather than west because the prevailing wind direction is westerly (from west to east) because it is north of Capricorn.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bear in mind that this explanation is extremely approximate and oversimplified, and that your assumption of deserts on the western side of a continent should be reversed north of about Capricorn and South of about Cancer, where the Trade Winds are replaced by the Westerlies.&lt;/p&gt;&#xA;" OwnerUserId="63" LastEditorUserId="63" LastEditDate="2017-03-31T04:23:11.440" LastActivityDate="2017-03-31T04:23:11.440" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="9996" PostTypeId="1" CreationDate="2017-03-29T18:43:05.810" Score="3" ViewCount="149" Body="&lt;p&gt;In a recent &lt;a href=&quot;https://www.lists.rdg.ac.uk/archives/met-jobs/2017-03/msg00090.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;met-jobs job posting&lt;/a&gt; (&lt;a href=&quot;http://www.esa.int/content/download/375286/16878272/file/RF-ECSAT(2016)001%20Rev2.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;different version here&lt;/a&gt;) for a researcher with a background in &lt;em&gt;climatology/meteorology/hydrology or&#xA;environmental sciences&lt;/em&gt;, I saw the phrase &lt;em&gt;breadboard retrieval algorithm&lt;/em&gt; (emphasis mine):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Sentinel-4 Retrieval: This Research Fellow Opportunity aims at&#xA;  testing of &lt;strong&gt;breadboard retrieval algorithms&lt;/strong&gt;. It is foreseen that&#xA;  synthetic satellite data, and possibly also real measurements data from&#xA;  airborne and satellite sensors will be used for this purpose. The&#xA;  activity might also cover the exploration of alternative retrieval&#xA;  approaches depending on the expertise and skills of the candidate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What is a breadboard (retrieval) algorithm?  Google Search yields precious few results, mostly from ESA.  Another usage I found&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://envisat.esa.int/workshops/validation_12_02/proceedings/meris/20_albert.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Albert, Preusker, and Fischer (2012), ENVISAT workshop&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Originally, three &lt;strong&gt;breadboard algorithms&lt;/strong&gt; were developed at the &#xA;  Freie Universität Berlin, and the knowledge for their creation &#xA;  was  transferred  to  ESA  /  Bomem  for  the  creation  of  the  ESA  algorithms.  In  the  meantime,  the  original  look-up  table approach was replaced for the breadboard algorithms by the use of artificial neural networks, which significantly eases the interpolation  of  the  simulation  results  onto  the  actual  viewing geometry.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Wikipedia tells me that, in electronics, a &lt;a href=&quot;https://en.wikipedia.org/wiki/Breadboard&quot; rel=&quot;nofollow noreferrer&quot;&gt;breadboard&lt;/a&gt; is &lt;em&gt;a construction base for prototyping electronics&lt;/em&gt;.  The details of the article do not appear relevant for the algorithm usage, but it makes me guess that the meaning of breadboard is related to prototyping.  However, from context, it is clear that the job ad or the ENVISAT paper has nothing to do with electronics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What does breadboard mean in the context of Earth observation retrieval algorithm development (which are the only contexts I could find)?  Is it simply a synonym for prototype, or does it have a different meaning?&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2017-03-30T08:36:15.230" LastActivityDate="2017-03-30T08:36:15.230" Title="What is a breadboard (retrieval) algorithm in the context of geophysical satellite retrievals/remote sensing?" Tags="|remote-sensing|terminology|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="9997" PostTypeId="1" CreationDate="2017-03-29T21:42:27.410" Score="9" ViewCount="5176" Body="&lt;p&gt;Earth's history is divided into eons, which are divided into eras, which are divided into periods etc. Consecutive time units differ in their geology and/or fossil species. But what events are the basis for dividing time into discrete bands?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Roughly speaking (forgive the approximation), the Hadean is the time before life, the Archean is the subsequent time before eukaryotes, the Proterozoic is the subsequent time before complex multicellular animals, and the Phanerozoic is the time since then. Yes, I know that the actual definitions are in terms of either what can be seen in the rocks or a certain number of Mya; and yes, I know the Ediacaran biota technically lived in the late Proterozoic; but, if I've understood correctly, the reason we separate these four parts of Earth's history is because of such distinctions. We can similarly divide the Phanerozoic into three eras based on the P-T and K-Pg mass extinctions. (However, the other three of the Big Five extinction events define the start of new periods rather than eras.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a more thorough list than this of the qualitative events and processes in Earth's history that motivate the specific ways we've defined eons, eras and periods? I realise there may be some arbitrariness in it, e.g. the fact that some mass extinctions &quot;only&quot; start a new period instead of a new era. However, I'll be satisfied with a summary of the key moments on which these divisions are based.&lt;/p&gt;&#xA;" OwnerUserId="7803" LastEditorDisplayName="user20559" LastEditDate="2021-06-26T11:11:45.320" LastActivityDate="2021-06-26T11:11:45.320" Title="How is geological time divided into units?" Tags="|geology|stratigraphy|mass-extinction|geologic-layers|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="9998" PostTypeId="2" ParentId="9996" CreationDate="2017-03-29T23:23:50.603" Score="4" Body="&lt;p&gt;When determining the retrieval algorithm for a spectrometer that will be built, it is first done on highly mathematical software platforms.  The software allows to the best curve approximation fitting equations to be derived (across all detected wavelengths) that will work for the proposed optics.  This is important because the diffracted light that is detected will interfere with itself very uniquely, depending on the geometry of your optical setup.   The data from the spectrometer's detector needs to be interpreted with a good curve fitting function so that you can get good wavelength resolution from your instrument.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When building a spectrometer for operational use on a satellite, it is ideal to be able to process the retrieval algorithm using hardware, rather than software.  The hardware processor allows real time function that isn't dependent on an operating system that requires lot's of computational overhead.  So, you build a breadboard that you can connect to your spectrometer so that your retrieval algorithm is processed using integrated circuits that can be programmed.  You essentially hard-code your algorithm into hardware.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Search for &quot;breadboard spectrometer&quot; in Google and you will find many examples.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, to answer your question.  A breadboard algorithm is developed using software that is used to help engineer the actual breadboards to be built in the future.  The software allows you to predict the response of your proposed circuitry to the spectrometer detector without having to actually build the breadboard yet.  Once your breadboard algorithm is setup properly (confirmed by testing the software version of your needed hardware) you can go about building the actual breadboard spectrometer model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once a breadboard spectrometer model is built and passes quality control checks, you can evaluate the spectrometer performance and see if its worth optimizing and fabricating a standalone instrument payload that can be deployed in the field (or in space).&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2017-03-30T04:07:20.270" LastActivityDate="2017-03-30T04:07:20.270" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="9999" PostTypeId="2" ParentId="9976" CreationDate="2017-03-29T23:40:43.953" Score="2" Body="&lt;h1&gt;foreword: Particles and Droplets&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Commonly, atmospheric particles can be considered as wet particles. E.g. when we talk about sulfate particles ($SO_4^{2-}$), these particles are actually droplets with dissolved sulfuric acid (or with a dissolved sulfate-cation compound).&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Mechanism involving $SO_2$&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;$SO_2$ is released as gas and it reacts to $SO_4^{2-}$ (sulfate). Basically, there are different reaction pathways for the formation of sulfate from $SO_2$:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$SO_{2,g}$ --(gas phase reaction)--&gt; $H_2SO_{4,g}$ --($H_2O$ accumulates)--&gt; &quot;sulfate particle&quot;&lt;/li&gt;&#xA;&lt;li&gt;$SO_{2,(g)}$ --(goes into solution)--&gt; $SO_{2,solution}$ --(formation)--&gt; $H_2SO_{4,solution}$ (deprotonizes directly)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Commonly, the second pathway is dominant. &lt;strong&gt;The relevant aspect is that it leads to the formation of ultra fine sulfate particles (sulfate droplets).&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sulfate particles are cloud condensation nuclei. That means that they support the formation of clouds. There are satellite pictures available, in which you can identify shipping lanes by lines of clouds. These clouds were formed because ships emit large amounts of $SO_2$ (at least outside of &lt;a href=&quot;https://en.wikipedia.org/wiki/Sulphur_Emission_Control_Area&quot; rel=&quot;nofollow noreferrer&quot;&gt;sulfur emission control areas&lt;/a&gt;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most clouds above the ocean reflect more solar radiation than the sea surface. In general, clouds above the ocean are considered as &quot;good clouds&quot; with respect to cooling the Earth. Since a large proportion of the Earth is covered by sea surface, one might wonder to generate clouds above it - e.g. by releasing $SO_2$. However, as far as I know, this process is relevant in the troposphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Releasing $SO_2$ into the stratosphere (as proposed in the linked article) is not meant to support cloud formation (correct me, if I am wrong). Nevertheless, the released $SO_2$ leads to ultra-fine sulfate particles. These sulfate particles themselves effectively scatter solar radiation and, thus, prevent it from reaching the Earth's surface. There is also a Wikipedia article available &lt;a href=&quot;https://en.wikipedia.org/wiki/Stratospheric_sulfate_aerosols_(geoengineering)&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, sulfate indirectly degrades the ozone layer: sulfate leads to the release of radicals that (and their successors) catalytically destroy ozone. See &lt;a href=&quot;http://dx.doi.org/10.1073/pnas.1615572113&quot; rel=&quot;nofollow noreferrer&quot;&gt;Keith et al. (2016)&lt;/a&gt; for a more detailed overview.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Why $CaCO_3$?&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The basic idea is to add salts of alkali metals that neutralize sulfuric acid and nitric acid (generated in the presence of sulfuric acid) when we emit $SO_2$. This will reduce the negative impact on the ozone layer. $CaCO_3$ is such a salt &lt;a href=&quot;http://dx.doi.org/10.1073/pnas.1615572113&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Keith et al., 2016)&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Why $Al_2O_3$?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Foreword:&lt;/strong&gt; I am not expert on this and just read some articles on this topic.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;http://dx.doi.org/10.5194/acp-15-11835-2015&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weisenstein et al. (2015)&lt;/a&gt;, fine aluminum particles (as well as diamonds) are an alternative to sulfate particles. According to them, aluminum is favourable. However, as studies on emissions from missiles and space crafts indicate, $Al_2O_3$ also has negative impacts on the ozone layer (&lt;a href=&quot;https://books.google.de/books?id=a2YrAAAAYAAJ&amp;amp;pg=PA166&amp;amp;lpg=PA166&amp;amp;dq=Al2O3%20stratosphere&amp;amp;source=bl&amp;amp;ots=xnPx9BMx_5&amp;amp;sig=JqqaiIlc2nfSG-fZEBSfGwBHr_A&amp;amp;hl=de&amp;amp;sa=X&amp;amp;ved=0ahUKEwiSlY2m__3SAhWLvhQKHQb_CbgQ6AEIRzAD#v=onepage&amp;amp;q=Al2O3%20stratosphere&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;SomeReport&lt;/a&gt;; &lt;a href=&quot;https://books.google.de/books?id=lRQ0AQAAMAAJ&amp;amp;pg=SA4-PA37&amp;amp;lpg=SA4-PA37&amp;amp;dq=Al2O3%20stratosphere&amp;amp;source=bl&amp;amp;ots=CA6b2ssqcP&amp;amp;sig=7vCBpBjykk0m5wtu42sRzuGpI1U&amp;amp;hl=de&amp;amp;sa=X&amp;amp;ved=0ahUKEwiSlY2m__3SAhWLvhQKHQb_CbgQ6AEIOTAB#v=onepage&amp;amp;q=Al2O3%20stratosphere&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;DoD, 2004&lt;/a&gt;): $Cl$ radicals are released that degrade ozone. $CaCO_3$ also counteracts here, too.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastEditorUserId="5594" LastEditDate="2017-03-30T10:34:35.150" LastActivityDate="2017-03-30T10:34:35.150" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10000" PostTypeId="2" ParentId="9996" CreationDate="2017-03-30T02:53:59.087" Score="1" Body="&lt;p&gt;This question would probably be better suited to engineering or electronic/electrical engineering.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My guess is that the breadboard will be used to test potential electronic circuits &amp;amp; being for ESA, possibly electronic circuits for satellites or probes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Breadboards can be used to test different connection geometries of electronic components. These would need to be optimized for weight &amp;amp; energy consumption, particularly if they are to be launched into outer space. Software (algorithms) exist where this can be done using a virtual breadboard rather than a physical one&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-03-30T02:53:59.087" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10001" PostTypeId="1" CreationDate="2017-03-30T03:43:34.093" Score="10" ViewCount="175" Body="&lt;p&gt;An excerpt from a section about the capital of Taiwan, in an article I wrote about &lt;a href=&quot;https://en.wikipedia.org/wiki/Air_pollution_in_Taiwan&quot; rel=&quot;nofollow noreferrer&quot;&gt;Air pollution in Taiwan&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Further more, in greater Taipei, the outdoor PM2.5 concentration in&#xA;  the air at ground-level up until the height of three-stories is around&#xA;  ten to twenty times higher than the concentration in the air at the&#xA;  height of four-story buildings and above. Levels of other hazardous&#xA;  suspended particles such as silicon and iron were equally found to be&#xA;  significantly lower when increasing altitude. Professor Chang-Fu Wu&#xA;  (吳章甫) of the same university attributed this to dust and traffic&#xA;  pollution.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, my question is, can this increasing pollution, when decreasing in altitude, be extrapolated to a negative (as compared to street-level) altitude as well, in a typical city? Intuitively, I would assume that parkings (don't forget about traffic tunnels) can be pretty bad, when thinking of sub-terrain places in a typical city, with regards to pollution? But what I am really interested in here, is finding out more about the increase in pollution in subways (underground transportation), as compared to the street-level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this problem perhaps being mitigated partly by sucking in air from a high altitude? &lt;strong&gt;(this shouldn't be seen as the question, it's just a remark)&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;P.S. &lt;strong&gt;(this is also not part of the question, so please don't close this question because I wrote a remark)&lt;/strong&gt;: I think finding higher ground is actually one of the best ways to escape from pollution in cities. But of course many cities will not give this advice to its citizens ... it might be unpopular and sound bad.&lt;/p&gt;&#xA;" OwnerUserId="7767" LastEditorUserId="6031" LastEditDate="2019-04-21T05:42:32.240" LastActivityDate="2019-04-21T05:42:32.240" Title="How much worse is the typical subway air, compared to street-level air pollution, in a typical city?" Tags="|air-pollution|pm2.5|particulates|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10003" PostTypeId="1" AcceptedAnswerId="10005" CreationDate="2017-03-30T09:48:44.217" Score="1" ViewCount="77" Body="&lt;p&gt;Reading about turbidity, I came across &lt;a href=&quot;http://www.lakeaccess.org/russ/turbidity.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;this web page&lt;/a&gt; with the frightening image shown below.&lt;/p&gt;&#xA;&lt;p&gt;Text immediately before reads:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Reasons for Natural Variation&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Algal turbidity varies seasonally and with depth in a complex manner as discussed previously in response to physical, chemical and biological changes in the lake. Inorganic and detrital particles from the watershed vary largely in response to hydrological events such as storms and snowmelt.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The figure caption reads:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Even relatively small amounts of wave action can erode exposed lakeshore sediments, in this case a mine pit lake from northeastern Minnesota. Can you guess what mineral was mined here?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Any ideas? I know there are bright red oxides of heavy metals like lead and mercury, certainly hope that's not the right answer.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jZN3i.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jZN3i.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-04-04T11:41:37.033" Title="What kind of mine pit in northeastern Minnesota could make residue that turns water turn bright red?" Tags="|geology|pollution|mining|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10004" PostTypeId="1" AcceptedAnswerId="15801" CreationDate="2017-03-30T09:55:01.337" Score="5" ViewCount="457" Body="&lt;p&gt;I found this image on a website - returned as a HTTP error 404 'not found'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the clouds look strangely repetitive. At first I thought the image had been &quot;photoshopped&quot;, but as @gerrit &lt;a href=&quot;https://earthscience.stackexchange.com/questions/10004/#comment19382_10004&quot;&gt;pointed out&lt;/a&gt; in a comment, each is different.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sky locally is clear and blue, but there are clouds above the water in the distance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this a real, recognizable type of formation? (the six repeated long, low clouds above the horizon in the distance) I have seen plenty of gravity wave cloud patterns in the sky and in the internet, but always from above, or below, never edge-on in a clear blue sky.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image found here: &lt;a href=&quot;http://wetlabs.com/sites/default/files/images/overboard.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://wetlabs.com/sites/default/files/images/overboard.jpg&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IuTb3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IuTb3.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2018-12-20T03:03:11.977" LastActivityDate="2018-12-20T03:03:11.977" Title="What might cause these &quot;wave clouds&quot; near the horizon? Could it be gravity waves?" Tags="|clouds|waves|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="10005" PostTypeId="2" ParentId="10003" CreationDate="2017-03-30T11:51:47.090" Score="3" Body="&lt;p&gt;From the red stain in the water &amp;amp; the rocks in the lower left of the picture it looks like iron ore.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, the red stain in the water appears to be a colloidal suspension, consistent with minor erosion of a bank rather than an aqueous stain caused by water reacting with sulfide minerals in the bank.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Iron_Range&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iron Range&lt;/a&gt; occurs in north eastern Minnesota.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-03-30T11:51:47.090" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10006" PostTypeId="2" ParentId="10003" CreationDate="2017-03-30T12:20:20.143" Score="2" Body="&lt;p&gt;Iron oxide gives the water its color.  The &lt;a href=&quot;https://en.wikipedia.org/wiki/Mesabi_Range&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mesobi Iron range&lt;/a&gt; is located in Minnesota.  It is very large iron deposit that is still mined today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QLRFW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QLRFW.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-03-30T12:20:20.143" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10007" PostTypeId="2" ParentId="9997" CreationDate="2017-03-30T12:59:05.840" Score="3" Body="&lt;p&gt;The divisions in the geologic time scale have evolved over time.&#xA;Its origins can be traced back to Nicolaus Steno in 1669 described two basic geologic principles. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The first stated that sedimentary rocks are laid down in a horizontal manner.&lt;/li&gt;&#xA;&lt;li&gt;The second stated that younger rock units were deposited on top of older rock units. &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Work by James Hutton, Charles Lyell and William Smith helped define &quot;principle of uniformitarianism&quot;. This work led to definitions in the Mesozoic and Paleozoic eons in Europe and Great Britain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Mesozoic and Paleozoic eons helped define the extinction events reflected in the fossil record. It was these correlations that led to the discovery of the extinction events and not the other way around.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Radiometric dating based on the work of Clair Patterson added absolute ages to the time scale.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Over time, the process of grouping together or splitting apart rock units  has grown more sophisticated as better dating techniques have been introduced and more data from mapped rock outcrops have been collected analysed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.ucmp.berkeley.edu/exhibit/histgeoscale.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.ucmp.berkeley.edu/exhibit/histgeoscale.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sepmstrata.org/page.aspx?pageid=22&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.sepmstrata.org/page.aspx?pageid=22&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://evolution.berkeley.edu/history/radiometric2.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://evolution.berkeley.edu/history/radiometric2.shtml&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-03-30T12:59:05.840" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10008" PostTypeId="1" AcceptedAnswerId="25474" CreationDate="2017-03-30T13:35:22.093" Score="3" ViewCount="529" Body="&lt;p&gt;I am looking for a definition of this term for wikipedia, with a reference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's mentioned on &lt;a href=&quot;https://en.wikipedia.org/wiki/Franz_Josef_Land&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;Franz Josef Land&quot;&gt;Franz Josef Land&lt;/a&gt; where it's indicated that the units are km-2/km. I'm curious about how this would be measured. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've found precious few mentions of this unit in the usual sources.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks in advance!&lt;/p&gt;&#xA;" OwnerUserId="7808" LastActivityDate="2023-08-18T16:22:41.760" Title="What is 'dissection rate'?" Tags="|geology|measurements|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10009" PostTypeId="2" ParentId="9994" CreationDate="2017-03-30T14:05:06.933" Score="16" Body="&lt;p&gt;Some of the driest deserts on Earth occur in the western side of continents and they are called Coastal Deserts. Examples of such deserts are the Atacama desert (Chile, the driest desert on Earth), the Baja California desert (USA/Mexico), the Namibia desert (southwestern Africa), and the Atlantic coastal desert of Morocco/western Sahara/Mauritania. In mid-latitudes, the western side of continents is most frequently occupied by deserts, while the eastern side tends to be covered by forests (e.g., Amazon rainforest).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UxcHH.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UxcHH.gif&quot; alt=&quot;desert distribution&quot;&gt;&lt;/a&gt;. Distribution of non-polar arid regions. Source: &lt;a href=&quot;https://pubs.usgs.gov/gip/deserts/what/world.html&quot; rel=&quot;noreferrer&quot;&gt;USGS&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Coastal deserts occur east of the strongest coastal upwelling regions in the world. The upwelling is associated with eastern boundary currents flowing equatorward (due to &lt;a href=&quot;https://en.wikipedia.org/wiki/Coriolis_force&quot; rel=&quot;noreferrer&quot;&gt;Coriolis&lt;/a&gt;): the &lt;a href=&quot;https://en.wikipedia.org/wiki/Canary_Current&quot; rel=&quot;noreferrer&quot;&gt;Canary Current&lt;/a&gt; (off Northwest Africa), the &lt;a href=&quot;https://en.wikipedia.org/wiki/Benguela_Current&quot; rel=&quot;noreferrer&quot;&gt;Benguela Current&lt;/a&gt; (off Southwest Africa), the &lt;a href=&quot;https://en.wikipedia.org/wiki/Humboldt_Current&quot; rel=&quot;noreferrer&quot;&gt;Humboldt Current&lt;/a&gt; (off Chile and Peru), and the &lt;a href=&quot;https://en.wikipedia.org/wiki/California_Current&quot; rel=&quot;noreferrer&quot;&gt;California Current&lt;/a&gt; (western North America). The prevailing winds in these regions are the &lt;a href=&quot;https://en.wikipedia.org/wiki/Trade_winds&quot; rel=&quot;noreferrer&quot;&gt;trade winds&lt;/a&gt; that flow parallel to the coast and generate upwelling dynamics: surface &lt;a href=&quot;https://en.wikipedia.org/wiki/Ekman_transport&quot; rel=&quot;noreferrer&quot;&gt;Ekman balance&lt;/a&gt; is setup (in deep enough waters) with water transport being to the right (left) of the wind in the northern (southern) hemisphere; this causes a deficit along the coast that needs a compensating flow in the deeper part of the water column bringing cold, nutrient rich waters (some of the most productive regions in the world) to the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eihoE.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eihoE.gif&quot; alt=&quot;upwelling animation&quot;&gt;&lt;/a&gt; Source Commons Wikipedia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cold waters near the ocean surface results in a cool, stable coastal atmosphere. In this region, &lt;a href=&quot;http://hqweb.unep.org/geo/GDOutlook/019.asp&quot; rel=&quot;noreferrer&quot;&gt;evaporation from the ocean is reduced&lt;/a&gt; and produces extremely low rainfall over land. Precipitation is limited to morning fog and produces some of the driest ecosystems on Earth. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Atacama_Desert&quot; rel=&quot;noreferrer&quot;&gt;Atacama desert&lt;/a&gt; is the best example of such environment with average rainfalls of 15 mm/year (the driest non-polar region). In some areas, they are trying to &lt;a href=&quot;http://newatlas.com/how-the-fogcatchers-of-the-atacama-are-bringing-water-to-the-driest-desert-on-earth/39040/&quot; rel=&quot;noreferrer&quot;&gt;take advantage of the little moisture the fog (Camanchaca)&lt;/a&gt; brings to establish some agricultural zones. The fog droplets are too small (1-40 micrometers) to form water drops and precipitate, so they use fog-catchers to collect moisture from the fog.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TxNrU.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TxNrU.jpg&quot; alt=&quot;Fog in Atacama&quot;&gt;&lt;/a&gt; Source: newatlas.com&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2017-03-30T14:27:57.463" LastActivityDate="2017-03-30T14:27:57.463" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10010" PostTypeId="1" AcceptedAnswerId="10018" CreationDate="2017-03-30T15:04:55.980" Score="3" ViewCount="173" Body="&lt;p&gt;Since burning coal leads to a variety of air pollutants, presumably a coal mine fire would also lead to air pollutants. My question is whether there have been any published studies on the emission rate of SO$_2$ from a mine fire, such as the Centralia fire in Pennsylvania?&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-03-31T08:17:03.907" Title="How much Sulfur Dioxide is emitted into the atmosphere from a mine fire?" Tags="|air-pollution|mining|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10011" PostTypeId="1" CreationDate="2017-03-30T16:34:44.187" Score="1" ViewCount="206" Body="&lt;p&gt;One way to &lt;em&gt;estimate&lt;/em&gt; the turbidity of water while in the field is to use a  turbidity tube. So far I've found two sources where I can get an idea of the locations of NTU markings along the tube.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The PDF file &lt;a href=&quot;http://www.virginia.edu/blandy/blandy_web/education/Bay/TurbidityTubeConstruction&amp;amp;Use_Myre_Shaw.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Turbidity Tube: Simple and Accurate Measurement of Turbidity in the Field&lt;/a&gt; - originally by Elizabeth Myre &amp;amp; Ryan Shaw at &lt;a href=&quot;http://www.mtu.edu/cee/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Michigan Tech&lt;/a&gt; is a nice introduction to the concept, outlines how to build a turbidity tube from simple materials and use it, and offers a table of numbers that comes with the following description:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;(UW Extension, 2003). Several tables of slightly different conversions are currently in use. This table was chosen from among the alternatives because of the reliability of the source and because the values were more conservative than in other tables. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Select Scientific in Australia sells a professional &lt;a href=&quot;http://selectscientific.com.au/turbidity-tube.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;two piece turbidity tube&lt;/a&gt;  and &lt;a href=&quot;https://i.stack.imgur.com/qXaPN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;one image&lt;/a&gt; (from &lt;a href=&quot;http://selectscientific.com.au/media/catalog/product/cache/8/thumbnail/600x/17f82f742ffe127f42dca9de82fb58b1/t/u/turbidity-tube_1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;) includes a photo with a length scale so that marking locations can be estimated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've made a rough plot of both below, and they are significantly different. That's not too surprising, as there is difference in construction as well as difference in opinions and between sources.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any further guidelines out there that I've missed? Any further advice before I make one and give it a try? Of course I'll include a centimeter scale so that it can be converted later, but sooner or later I'll need to settle down and choose a conversion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;note:&lt;/strong&gt; I am most interested in the &lt;em&gt;higher turbidity&lt;/em&gt; end of the scale, say above 50 NTU. This is not traditionally the turbidity tube's &quot;best end&quot;, but it's where the two sources I've found diverge the most.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ij2Gl.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ij2Gl.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; plot of some estimates for position of NTU markings on a turbidity tube as a function of distance from the bottom in centimeters. The solid line is tabulated data in the &lt;a href=&quot;http://www.virginia.edu/blandy/blandy_web/education/Bay/TurbidityTubeConstruction&amp;amp;Use_Myre_Shaw.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Michigan Tech PDF&lt;/a&gt;, the dashed line is estimated from the &lt;a href=&quot;https://i.stack.imgur.com/qXaPN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Select Scientific photo&lt;/a&gt;. Curves are from the equations below. Since they are power-law, they show as straight lines on the log-log plot on the right.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$NTU_{SelSci} \approx 1420 \times H_{cm}^{-1.259}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$NTU_{MTech} \approx 4043 \times H_{cm}^{-1.511}$$&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2017-03-31T02:03:14.927" LastActivityDate="2017-03-31T02:03:14.927" Title="Guidelines for locations of NTU markings on a turbidity tube" Tags="|turbidity|field-measurements|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10012" PostTypeId="1" AcceptedAnswerId="10016" CreationDate="2017-03-30T17:25:18.107" Score="4" ViewCount="938" Body="&lt;p&gt;Here's what I know:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The lithosphere is hard because it is cold and low-pressure. &lt;/li&gt;&#xA;&lt;li&gt;The asthenosphere is more deformable because of higher temperatures and pressures. &lt;/li&gt;&#xA;&lt;li&gt;The mesosphere is below the asthenosphere and presumably experiences higher temperatures and pressures than the asthenosphere. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Why does the asthenosphere act like a lubricant for tectonic plates to slide over? Why is the mesosphere &lt;em&gt;more&lt;/em&gt; viscous than the asthenosphere? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What's causing the differences in the viscosity between these regions, and is there more than viscosity going on?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="4439" LastActivityDate="2017-03-30T20:30:58.063" Title="What's up with the &quot;jelly sandwich&quot; analogy of the lithosphere, asthenosphere and mesosphere?" Tags="|geology|geophysics|mantle|crust|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10013" PostTypeId="2" ParentId="10001" CreationDate="2017-03-30T18:03:38.257" Score="7" Body="&lt;h1&gt;Depends on what type of pollution you are talking about&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0013935115300426&quot; rel=&quot;noreferrer&quot;&gt;Moreno et al., 2015&lt;/a&gt; studied this problem in Barcelona, and compared Metro (subway) to trams, buses, and walking in various parts of the city. There is a massive overabundance of data in this paper that mostly speaks for itself, but let me summarize.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The subway was in first place or last place in most measures; it was the only system that didn't occupy the environment of the city streets. So these comparisons are probably exactly what you are looking for. Subway air had the lowest count of particulate matter, and the highest modal particle size; &lt;a href=&quot;https://en.wikipedia.org/wiki/Particulates&quot; rel=&quot;noreferrer&quot;&gt;both of these are good&lt;/a&gt;. However, at the same time, the PM$_{2.5}$ (fine particulates which are particularly dangerous carcinogens) for subway and bus were notably higher than for tram and walking. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Black_carbon#Public_health_impacts&quot; rel=&quot;noreferrer&quot;&gt;black carbon&lt;/a&gt; levels were in the middle of the road; lower than for pedestrians but higher than bus or tram. However, the authors note that black carbon may have been overestimated for the subways; so these levels could have been lower.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Carbon monoxide is largely related to combustion engine usage; CO levels were lowest on the electric trams, and higher on the other modes of transportation. Carbon Dioxide, on the other hand, is largely related to other passengers breathing; CO$_2$ was highest on the crowded vehicles and much lower for pedestrians. CO$_2$, unlike the others, I don't think is a chronic health risk at the observed concentrations.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Conclusion&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;There is a lot of information in that paper, and I am not really qualified to judge the health risks from one factor against another. I can note that in no health measures does the subway have the worst air quality between the four transportation modes; and there is no other mode that has better air quality than the subway in all measures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suppose it is safest to say that, in a statistical sense across multiple measures, the subway air is not &lt;em&gt;significantly&lt;/em&gt; more unhealthy than street level air. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2017-03-30T18:03:38.257" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10014" PostTypeId="2" ParentId="9987" CreationDate="2017-03-30T18:22:26.083" Score="1" Body="&lt;p&gt;According the an Oregon State &lt;a href=&quot;http://volcano.oregonstate.edu/chaine-des-puys&quot; rel=&quot;nofollow noreferrer&quot;&gt;website&lt;/a&gt;, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Volcanism far from the edges of tectonic plates, such as Chaine des&#xA;  Puys, is rare. Changes in the mantle may have led to volcanism at&#xA;  Chaine des Puys. Several lines of evidence indicate thinning of the&#xA;  crust and upwelling of the asthenosphere. The rising mantle &quot;diapir&quot;&#xA;  was probably a total of 30-60 miles (50-100 km) in diameter.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Cha%C3%AEne_des_Puys&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chain des Puys&lt;/a&gt; is the 40km long chain of volcanic features to which Puy de Dome belongs. It sounds like the causes are not completely understood. Unfortunately, all the papers I could find on the topic are in French (understandably), so if you can read French you can try Google Scholar to see if there is more info there. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2017-03-30T18:22:26.083" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10015" PostTypeId="2" ParentId="9978" CreationDate="2017-03-30T18:53:46.720" Score="6" Body="&lt;h1&gt;The .06 microseconds figure doesn't sound accurate&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_moments_of_inertia&quot; rel=&quot;nofollow noreferrer&quot;&gt;moment of inertia&lt;/a&gt; for a solid sphere is &lt;span class=&quot;math-container&quot;&gt;$$I = \frac{2mr^2}{5},$$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt; is the mass of the sphere and &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; is its radius. Applied to the Earth, this gives us &lt;span class=&quot;math-container&quot;&gt;$$I = \frac{2\cdot5.972\times10^{24} \text{ kg} (6371000 \text{ m})^2}{5} = 9.70\times10^{37} \text{ km-m}^2.$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A simplified estimate of moment of inertia for the water in the three gorges dam is &lt;span class=&quot;math-container&quot;&gt;$mr^2$&lt;/span&gt;. The change in moment of inertia from raising that water by 175m can be calculated by &lt;span class=&quot;math-container&quot;&gt;$$\begin{align}\Delta I &amp;amp;= m_{water}\left[(r_{earth}+175)^2-r_{earth}^2\right] \\ &amp;amp;= 39\times10^{12}\left(6371175^2-6371000^2\right) \\&amp;amp;= 8.69\times10^{22} \text{ km-m}^2.\end{align}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming that the angular momentum (&lt;span class=&quot;math-container&quot;&gt;$L$&lt;/span&gt;) of the Earth stays constant, then since &lt;span class=&quot;math-container&quot;&gt;$L=I\omega$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$$I_{before}\omega_{before} = I_{after}\omega_{after},$$&lt;/span&gt; or &lt;span class=&quot;math-container&quot;&gt;$$\omega_{after}=\omega_{before}\frac{I_{before}}{I_{after}}.$$&lt;/span&gt; The angular velocity, &lt;span class=&quot;math-container&quot;&gt;$\omega$&lt;/span&gt;, of the Earth (before) is &lt;span class=&quot;math-container&quot;&gt;$7.292\times10^{-5} \text{ radians/s}$&lt;/span&gt;. The discrepancy between the before and after moment of inertia is so insignificant that I would be wary of floating point error on this calculation, but using Python2 I calculate the delta in rotational speed to be &lt;span class=&quot;math-container&quot;&gt;$6.776\times10^{-20} \text{radians/s}$&lt;/span&gt;. For a rotation of the Earth this means the rotation will take about 80 picoseconds longer, or 0.00008 milliseconds. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Conclusion&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The statements made by VSauce don't match up with Physics 101. I am not inclined to believe this claim unless there is some other explanation or compelling evidence. Given that the magnitude of the change in rotational speed is three orders of magnitude less than he claims, and that 80 picoseconds is about 1/4 of the time it would take your computer to add 2 integers, I think it is safe to say that this is not measurable. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="6703" LastEditDate="2019-01-12T20:17:10.600" LastActivityDate="2019-01-12T20:17:10.600" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="10016" PostTypeId="2" ParentId="10012" CreationDate="2017-03-30T20:30:58.063" Score="2" Body="&lt;p&gt;The introduction to &lt;a href=&quot;http://geophysics.wustl.edu/seminar/2013_Morgan_EPSL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Morgan et al., 2013&lt;/a&gt; has a good summary of the features you are asking about, as well as proposing a mechanism for why it happens. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the intro:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Earth’s mantle underneath the tectonic plates, commonly referred&#xA;  to as asthenosphere, is known to be the lowest viscosity region of the&#xA;  upper mantle. Several potential mechanisms have been suggested to be&#xA;  responsible for this low viscosity zone. These mechanisms...include:&#xA;  (1) the temperature and pressure dependence of the mantle rheology may&#xA;  lead to a viscosity minimum between 70 and 200 km depth; (2) a small&#xA;  and immobile fraction of partial melts may weaken the mantle; (3) wet&#xA;  mantle below its dry solidus (deeper than about 70 km) would be&#xA;  expected to be weaker than shallower mantle that dehydrated during&#xA;  partial melting at mid-ocean ridges (MOR)—but this mechanism does not&#xA;  explain the physical origin for the base of the asthenosphere; (4) a&#xA;  reduction in mantle grain size within the asthenosphere.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The paper's proposed cause for this is that: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the sub-oceanic asthenosphere forms because it is the ‘graveyard’ for&#xA;  rising (i.e. hotter-than-average mantle) plumes. In this view, below&#xA;  the plate-age-dependent 60–100 km-thick oceanic lithosphere there&#xA;  exists a pool of hot plume material that has risen as far as the&#xA;  overlying thermal and/or compositional lithosphere  will allow.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Whether that mechanism is correct or not, only time will tell. In conclusion, due to the temperature and pressure characteristics of the asthenosphere, it is less viscous than the chemically identical mesosphere. This may be because of its place on temperature and pressure curves, because it contains pockets of partially molten rock, because rising mantle plumes make the asthenosphere actually hotter than the mesosphere, or otherwise. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2017-03-30T20:30:58.063" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10017" PostTypeId="1" CreationDate="2017-03-30T23:56:52.303" Score="4" ViewCount="88" Body="&lt;p&gt;&lt;a href=&quot;https://quod.lib.umich.edu/j/jii/4750978.0003.102/--from-michigan-to-taiwan-air-pollution-technology?rgn=main;view=fulltext&quot; rel=&quot;nofollow noreferrer&quot;&gt;An article&lt;/a&gt; seems to assert that air pollution can be held in place (or 'trapped') by high mountains surrounding the area of air pollution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This seems very understandable. But the same article seems to &lt;strong&gt;assert&lt;/strong&gt; that this is the case for water (&lt;em&gt;read: lakes, seas, et cetera&lt;/em&gt;) as well? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To clarify, I will quote the relevant passage:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Taiwan's topography is one cause of its air pollution problem. Taipei,&#xA;  the capital and largest city, is effectively in a &quot;bowl&quot; ringed by&#xA;  mountains, while other industrial centers are along the northern and&#xA;  western coasts of the island, &lt;strong&gt;surrounded by water&lt;/strong&gt; and high mountains.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My question is: how is water surrounding an area of pollution, able to 'trap' that pollution, or otherwise deteriorate air quality?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please provide at least one relevant source, when answering this question. Your knowledge would be much appreciated.&lt;/p&gt;&#xA;" OwnerUserId="7767" LastEditorUserId="7767" LastEditDate="2017-04-01T15:02:47.077" LastActivityDate="2017-04-01T15:02:47.077" Title="How is water surrounding an area of pollution, able to 'trap' that pollution, or otherwise deteriorate air quality?" Tags="|air-pollution|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10018" PostTypeId="2" ParentId="10010" CreationDate="2017-03-31T08:17:03.907" Score="3" Body="&lt;p&gt;All coal deposits are different. Coal chemist is highly varied, and the amounts of sulfur and heavy metals with the coal seams varies with each deposit &amp;amp; within seams. This is due to the conditions prevalent when the coal seams were formed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consequently, the amount of sulfur dioxide emitted when coal is burned, whether in a power station or a mine fire depends on the amount of sulfur in the deposit the coal came from.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Without having an assay of the amount of sulfur in the coal or measuring how much sulfur dioxide is generated in a fire it is impossible to know how much sulfur dioxide will be produced.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-03-31T08:17:03.907" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10021" PostTypeId="1" CreationDate="2017-03-31T15:54:08.017" Score="4" ViewCount="145" Body="&lt;p&gt;I've gotten into paddle surfing and I'm looking for a place to live and surf. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've been looking at an buying a condo in Cocoa Beach because of it’s proximity to Orlando and Cocoa’s decent but consistent surf break. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What concerns me is the perchlorate from all the rockets that launch from the Kennedy Space Center and also the jet fuel(kerosene) from Patrick Air Force Base. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do you think that’s a legitimate health concern?&#xA;I'm curious because some of the properties seem &quot;inexpensive&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT:&#xA;I'm curious about the safety of surfing. &#xA;My guess is it's fine, the ocean is massive; I don't swallow that much water surfing, but always some.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It does seem there are some contaminants in the water. It'd be a bummer to get Thyroid cancer or something like that. I linked to a book mentioning it below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://books.google.com/books?id=jlgBMowCT1YC&amp;amp;pg=PA9&amp;amp;lpg=PA9&amp;amp;dq=cocoa+beach+perchlorate&amp;amp;source=bl&amp;amp;ots=A7evkeQGt9&amp;amp;sig=oNhyFH8QCwDXARMJNDKbmtjI-8Y&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwj668bLjoLTAhUJRSYKHcgJDvQQ6AEIGjAA#v=onepage&amp;amp;q=cocoa%20beach%20perchlorate&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://books.google.com/books?id=jlgBMowCT1YC&amp;amp;pg=PA9&amp;amp;lpg=PA9&amp;amp;dq=cocoa+beach+perchlorate&amp;amp;source=bl&amp;amp;ots=A7evkeQGt9&amp;amp;sig=oNhyFH8QCwDXARMJNDKbmtjI-8Y&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwj668bLjoLTAhUJRSYKHcgJDvQQ6AEIGjAA#v=onepage&amp;amp;q=cocoa%20beach%20perchlorate&amp;amp;f=false&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7817" LastEditorUserId="7817" LastEditDate="2017-04-01T01:43:01.287" LastActivityDate="2017-04-01T01:43:01.287" Title="Does perchlorate(rocket fuel) and jet fuel make the salt and ground water near Cape Canaveral dangerous?" Tags="|ocean|geochemistry|groundwater|pollution|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10022" PostTypeId="1" AcceptedAnswerId="10024" CreationDate="2017-04-01T09:48:29.307" Score="7" ViewCount="173" Body="&lt;p&gt;When searching for continental trends in climate I could not find clear sources broken down to regions or continents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: is it proper to talk of global warming as a homogenous trend or is there actually a difference between trends when the data is broken down per continent or region for example. Can anyone point me to clear sources on climate change trends per region or continent?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A hypothetical example would be: while the south-American climate remains stable polar climates warm up. Or, the poles warm up faster than south-American climate.&lt;/p&gt;&#xA;" OwnerUserId="7822" LastActivityDate="2017-04-01T14:21:24.430" Title="Is climate change homogenous globally" Tags="|climate-change|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10023" PostTypeId="1" AcceptedAnswerId="10026" CreationDate="2017-04-01T13:48:49.050" Score="3" ViewCount="146" Body="&lt;p&gt;I hope this is the right SE site...I was unsure if to post here or on Physics, but I see there are quite many questions about oil here. So, my question is the following: I would like to compare the huge oil production of Texas, vs the minuscule (in comparison) oil production of a small region in Europe. I know it's silly, but some people are making this comparison and I want to show it's meaningless with actual numbers. Texas oil production is easy to find:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.rrc.state.tx.us/oil-gas/research-and-statistics/production-data/texas-monthly-oil-gas-production/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.rrc.state.tx.us/oil-gas/research-and-statistics/production-data/texas-monthly-oil-gas-production/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1 131 557 443 barrels for 2016: I'm a little bit surprised they can pin it down to the single barrel (I guess much more than a barrel is lost in spillage, contamination, etc.), but oh, well. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The European region I'm considering has a production of about 3.75 million tons of oil. So, how do I compare barrels (a unit of volume) to tons (a unit of mass)? For a rough number, I thought oil must be lighter than water, since it floats on it, so if I consider water density, I'll get an upper bound. Now, since an oil barrel seems to correspond to 159 liters &lt;a href=&quot;https://en.wikipedia.org/wiki/Barrel_(unit)#Oil_barrel&quot; rel=&quot;nofollow noreferrer&quot;&gt;according to Wikipedia&lt;/a&gt;, I would get an upper bound of &#xA;$$(1\ 131\ 557\ 443 * 159)/1000\ m^3 * 1 \ ton /m^3 = 179\ 917\ 633 \ tons $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;About 180 million tons of oil (thus the comparison is ridiculous, as I suspected). But oil density is less than water, and it's actually very dependent on the type of oil being extracted, so to get a lower bound I will consider a density of $790 \ kg/m^3$ which I think is fairly low for Texas oil (correct me if I'm wrong). So I get about 142 million tons of oil, and this is still nearly two orders of magnitude larger than 3.75 million tons of oil. Is this correct? Would it be possible to get sharper estimates, or is this the best one could hope to get, given all the uncertainties in this calculation?&lt;/p&gt;&#xA;" OwnerUserId="7824" LastEditorUserId="2470" LastEditDate="2017-04-02T02:52:00.990" LastActivityDate="2017-04-02T02:52:00.990" Title="How to compare the oil production in barrel vs production in tons" Tags="|geology|petroleum|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10024" PostTypeId="2" ParentId="10022" CreationDate="2017-04-01T14:21:24.430" Score="9" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is climate change homogenous globally?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not at all. The Arctic (both the Arctic Ocean and far northern land masses) has and will continue to experience greater temperature changes than other parts of the Earth. Other than the Arctic, land masses have and will continue to experience greater temperature changes than the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The warming seen to date is a portrayed below. This image portrays annual temperature anomalies averaged over the last ten years, with anomalies relative to a 1951 to 1980 baseline.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/X3b0o.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/X3b0o.png&quot; alt=&quot;Image portraying temperature anomalies averaged over the last ten years, compared to a 1951 to 1980 baseline. Arctic regions have experienced the greatest increases. A small number of spots have experienced cooling. Temperature changes are far from uniform.&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;Source: &lt;a href=&quot;https://data.giss.nasa.gov/gistemp/maps&quot; rel=&quot;noreferrer&quot;&gt;https://data.giss.nasa.gov/gistemp/maps&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Can anyone point me to clear sources on climate change trends per region or continent?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The IPCC reports is always a good start. The most recent is the &lt;a href=&quot;http://www.ipcc.ch/report/ar5&quot; rel=&quot;noreferrer&quot;&gt;fifth assessment report&lt;/a&gt;. The site I used to make the above map, &lt;a href=&quot;https://data.giss.nasa.gov/gistemp/maps&quot; rel=&quot;noreferrer&quot;&gt;Global Maps from GHCN v3 Data&lt;/a&gt; is also a good source.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-04-01T14:21:24.430" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10025" PostTypeId="1" CreationDate="2017-04-01T14:46:51.670" Score="6" ViewCount="111" Body="&lt;p&gt;I have a series of records of annual maximum daily rainfall for a station for about 80 years (1935-2014). Only one value is very high compared with the others, but in this year, the other close rain-gauges didn't record such a high value. What are the conditions/tests to remove or keep this high value in the statistical analysis of rainfall data?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6KWuG.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6KWuG.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7826" LastEditorUserId="10681" LastEditDate="2018-03-16T00:02:42.677" LastActivityDate="2018-03-17T20:59:15.370" Title="Accepting/refusing high rainfall measurement" Tags="|meteorology|hydrology|rainfall|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10026" PostTypeId="2" ParentId="10023" CreationDate="2017-04-01T15:54:46.100" Score="5" Body="&lt;p&gt;I suspect that 3.75 million tons of oil is actually tons of oil equivalent (toe). This is a unit of energy rather than mass. The US uses a barrel of oil equivalent (boe) as a measure of energy. The advantage of these energy units is that natural gas, coal, and refined petroleum products can all be measured in terms of tons or barrels of oil equivalent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The US still measures oil production in volume. Depending on the quality of the crude oil, it takes &lt;a href=&quot;http://www.spe.org/industry/unit-conversion-factors.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;between 6.5 and 7.9 barrels of oil to yield one ton of oil equivalent, with 7.33 barrels as an average value&lt;/a&gt;. That means that the 1 131 557 443 barrels produced in Texas in 2016 represents somewhere between 143 to 174 million tons of oil equivalent.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="2470" LastEditDate="2017-04-02T02:49:28.723" LastActivityDate="2017-04-02T02:49:28.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10033" PostTypeId="1" CreationDate="2017-04-02T12:06:37.350" Score="5" ViewCount="139" Body="&lt;p&gt;We're about to do lime wash on one of our heritage buildings. We decided to use ochre as pigment because it comes from earth. My boss says with any pigment that comes from earth, we don't need to worry about discoloration in lime mortar, which is high in pH value. But some of our guys are using laterite powder for brick repairs and I wonder if it is a good choice. Would it discolor in lime mortar? How would it react? Please, someone answer me!&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Maybe I need to mention more info in my question. I'm from myanmar and we've got a lot of sunshine and a lot of rain too during moonsoon season. We're not doing new buildings, just repairing a historic building built around 1900. This building is basically abandoned for decades, and it's quite big. A lot of bricks need to be replaced, but in some areas we intend to use lime mortar with brick dust to imitate a brick rather than raking out and replacing with a new one. But we're not achieving the same color as the original brick but when we add laterite powder to lime mortar, color is satisfactory. Our only concern is that we don't want the repaired areas faded away after three or four years. &lt;/p&gt;&#xA;" OwnerUserId="7836" LastEditorUserId="6" LastEditDate="2017-04-05T11:54:59.960" LastActivityDate="2017-04-05T11:54:59.960" Title="Pigments from earth" Tags="|geology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10036" PostTypeId="2" ParentId="10033" CreationDate="2017-04-02T13:08:46.003" Score="3" Body="&lt;p&gt;Earth pigments generally don't discolor becasue they are already fully oxidized, unlike most artificial pigments. Laterite is commonly used to make bricks, so I doubt you will see any effects you would not already see on the bricks themselves. Just check to see if it is fired or not. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are repairing brickwork identifying the causes of stains will help:&lt;br /&gt;&lt;a href=&quot;http://www.ashireporter.org/HomeInspection/Articles/Brick-Stains-Identification-Prevention/1127&quot; rel=&quot;nofollow noreferrer&quot;&gt;Brick Stains: Identification &amp;amp; Prevention&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most staining is caused by improper cleaning not the mortar, lime run for instance is not actually caused by the lime. The only material you really have to worry about with lime is manganese, laterite is rich in manganese, but this is only an issue if it is fired first which mobilizes the manganese, acid washing further mobilizes it, the lime actually causes it to precipitate, if it is unfired however it is already stable and mixing it with the lime will not matter. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="595" LastEditDate="2017-04-04T07:55:52.323" LastActivityDate="2017-04-04T07:55:52.323" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10037" PostTypeId="1" AcceptedAnswerId="10044" CreationDate="2017-04-02T13:40:02.487" Score="3" ViewCount="8733" Body="&lt;p&gt;I live in the Northern Emisphere. One of the things I have been taught when I was in high school is that winter is colder than summer because in that season we're at an unfavorable angle and nights last longer than days, &lt;em&gt;despite Earth being closer to the Sun during winter months&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does this really mean that on the Equator, where day and night are of the same length all year long, winter is the hottest season*?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does this also mean that Winters in the Southern hemisphere are colder than our Summers and their Winters are hotter than or Summers (or that they would be if not for the Gulf Stream, air currents and other temperature-changing effects)?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;*I can think of a different reason that would make equinoxes hotter (more sunrays per surface area when the sun hits from above all day long) but I have no idea of which effect would be greater.&lt;/p&gt;&#xA;" OwnerUserId="7837" OwnerDisplayName="Zachiel" LastActivityDate="2017-04-03T05:02:07.743" Title="Is winter hotter at the Equator?" Tags="|temperature|geophysics|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10038" PostTypeId="1" AcceptedAnswerId="10052" CreationDate="2017-04-02T16:58:23.007" Score="7" ViewCount="11573" Body="&lt;p&gt;There are several number of cloud types, but I only know that cumulonimbus clouds discharge electricity, which in turn produces thunder and lightning. Is this type of cloud (cumulonimbus) the only cloud that can produce an electrical discharge or are there other clouds that can produce an electrical discharge?&lt;/p&gt;&#xA;" OwnerUserId="7785" LastEditorUserId="6093" LastEditDate="2017-04-03T00:02:03.027" LastActivityDate="2017-04-06T14:50:48.623" Title="Which clouds can produce lighting and thunder?" Tags="|meteorology|clouds|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10039" PostTypeId="2" ParentId="10037" CreationDate="2017-04-02T17:18:19.263" Score="3" Body="&lt;p&gt;The mean temperature on the equator for three locations (South America, Asia, Africa) show that while there is a small seasonal variation, the timing of the peak is not the same at every point. This is presumably because other atmospheric effects dominate the climate at the equator - not just the distance to the Sun:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/u5aCA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/u5aCA.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Data extracted from &lt;a href=&quot;https://en.wikipedia.org/wiki/Equator&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia article&lt;/a&gt;)&#xA;If you wanted the effect of the solar irradiation alone - the distance from aphelion to perihelion varies from 0.9832899 AU to 1.0167103 AU (about a 3% variation). Since solar irradiance goes with the inverse square of the distance, you expect the solar intensity to change by 6%, with the &quot;hottest&quot; moment coming in early January.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A simplified black body model has the Earth's temperature responding according to the Stefan-Boltzmann law - which would make the temperature increase with the fourth root of the incident power, or 1.5%. For a mean surface temperature of 27°C at the equator (300K) that would be a 10K change...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But a &quot;simple black body model&quot; is not at all how Earth works - so we're back to &quot;all the other effects&quot; completely dominating the seasonal variations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a reference, you might want to consult &lt;a href=&quot;http://www.geog.ucsb.edu/ideas/Insolation.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this link&lt;/a&gt; which possibly contains more information that you would ever want...&lt;/p&gt;&#xA;" OwnerUserId="453" LastEditorUserId="453" LastEditDate="2017-04-02T18:39:37.187" LastActivityDate="2017-04-02T18:39:37.187" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10041" PostTypeId="1" AcceptedAnswerId="10042" CreationDate="2017-04-02T20:47:15.993" Score="5" ViewCount="431" Body="&lt;p&gt;Having learned that fog often forms when wet air hits cold land, I’m now wondering why San Francisco sees so much more fog than Seattle does.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They’re both Marine West Coast, with moist, westerly Pacific Ocean winds, and both have water on both their east and west sides.&lt;/p&gt;&#xA;" OwnerUserId="7842" LastActivityDate="2017-04-03T01:33:00.503" Title="Why does San Francisco see so much more fog than Seattle?" Tags="|meteorology|climate|clouds|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10042" PostTypeId="2" ParentId="10041" CreationDate="2017-04-03T01:33:00.503" Score="3" Body="&lt;p&gt;As njuffa alludes to there is a current just offshore from the California coast. This is a deep, cold ocean current. As it hits the continental shelf off the coast it is deflected upwards towards the ocean's surface. But here's where it gets different: a thermal low that forms in the Central Valley of California during the summer draws in the air from the Pacific through the delta and bay waters. As that air meets the cold upwelling water that was deflected upward by the continental shelf, it draws moisture from it. That cold water also cools the air which then forms fog and gets drawn into San Francisco. As that moist air gets drawn further inland, it warms sufficiently for the fog to return to vapor. This actually cools the Central Valley to where this onshore breeze (we call it the delta breeze) gets shut off, the valley warms again, and the whole cycle repeats. Of course, other weather factors (position of the Eastern Pacific High, for instance) can override this process, but it is pretty much the standard summertime pattern. &lt;br&gt;&lt;br&gt;&lt;sub&gt;If you need citations, I'm not sure I can provide them, as this is something I learned in a physical geography class in college many years ago. I've also seen some other explanations that are just plain wrong.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2017-04-03T01:33:00.503" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10044" PostTypeId="2" ParentId="10037" CreationDate="2017-04-03T05:02:07.743" Score="6" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Does this really mean that on the Equator, where day and night are of the same length all year long, winter is the hottest season?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;By &quot;winter&quot;, I assume you mean December, January, and February. The answer is &quot;No!&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Insolation varies on an annual basis outside of the tropics, one maximum and one minimum every year. This is not the case in tropical regions, where available insolation has two local maxima and two local minima every year. This effect is greatest at the equator. The graph below depicts available insolation at increments of 30 degrees latitude, from the equator to the north pole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/d2pgw.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/d2pgw.gif&quot; alt=&quot;Plot of available insolation at various latitudes as a function of time of year&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that at the equator, available insolation achieves local maxima at the two equinoxes and local minima at the two solstices. The reason is that the Sun is directly overhead at local noon on the equinoxes but is 23.5 degrees from vertical at local noon on the solstices. Sunlight has to travel through more air at the solstices than at the equinoxes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The slight variations in insolation at the equator are easily overcome by climate. Equatorial regions tend to have wet seasons and dry seasons. When these occur depends much more on wind patterns than it does on aphelion / perihelion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Does this also mean that Winters in the Southern hemisphere are colder than our Summers and their Winters are hotter than or Summers?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The answer is once again &quot;No&quot;. The slight variation in insolation due to the Earth's eccentric orbit is once again easily overcome by other phenomena. The driving characteristic for this part of the question is that the northern hemisphere has much more land mass than does the southern hemisphere. This means that except for polar regions, southern hemisphere seasons tend to be more moderate than do northern hemisphere seasons.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-04-03T05:02:07.743" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10045" PostTypeId="1" AcceptedAnswerId="10050" CreationDate="2017-04-03T09:59:26.850" Score="12" ViewCount="783" Body="&lt;p&gt;I am at a loss for the precise, correct terminology, but I have read in Wikipedia that &lt;a href=&quot;https://en.wikipedia.org/wiki/Uluru&quot; rel=&quot;nofollow noreferrer&quot;&gt;Uluru&lt;/a&gt; is not a monolith, but &lt;a href=&quot;https://en.wikipedia.org/wiki/Savandurga&quot; rel=&quot;nofollow noreferrer&quot;&gt;Savandurga&lt;/a&gt; is, and that I probably shouldn't be using the word monolith to begin with, but instead use &lt;a href=&quot;https://en.wikipedia.org/wiki/Inselberg&quot; rel=&quot;nofollow noreferrer&quot;&gt;inselberg&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was once told that Uluru is a giant rock, just sitting in the soil. I think this is probably impossible and that it is part of the underlying bedrock of the area, but is that the case for all/most inselbergs? Are they identified primarily by how isolated they appear &lt;em&gt;above ground&lt;/em&gt; only?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; Savandurga (India) from &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Savandurga.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. See more photos at &lt;a href=&quot;http://tourist-places-around-the-world.blogspot.com/2012/02/savandurga-hill-composed-entirely-of.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Savandurga - A Hill composed entirely of only one rock&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/09Xta.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/09Xta.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; Uluru (Australia) from &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Uluru_(Helicopter_view)-crop.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/uKcpn.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uKcpn.jpg&quot; alt=&quot;enter description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="321" LastEditDate="2020-02-05T15:10:13.150" LastActivityDate="2020-02-05T15:10:13.150" Title="Are &quot;monoliths&quot; giant, isolated rocks sitting in dirt, or are they continuous with bedrock" Tags="|rocks|land-surface|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="10046" PostTypeId="1" AcceptedAnswerId="10059" CreationDate="2017-04-03T11:36:03.387" Score="5" ViewCount="241" Body="&lt;p&gt;I am trying to compare NDVI values computed from MODIS Surface Reflectance(MOD09) with the NDVI product (MOD13).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;MODIS Surface reflectance Collection 5 products include a Data State QA field that I am using to estimate which pixels are best suited for computing NDVI.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A part of this field is labeled &lt;strong&gt;Aerosol quantity&lt;/strong&gt;. The values in this field seem to significantly affect the result of NDVI computation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The explanation of the possible values of this field in the MOD09 Users' Guide  seems not entirely clear to me.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;         | 00 - climatology&#xA;aerosol  | 01 - low&#xA;quantity | 10 - average&#xA;         | 11 - high&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The last three values are clear, while the meaning of the &lt;strong&gt;climatology&lt;/strong&gt; value is somewhat non-intuitive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have selected a crop field and calculated NDVI for all pixels clear of clouds or cloud shadows during one vegetation period and observed the following:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qj9aB.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qj9aB.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems that results with low aerosol quantity (green points) match well with the results obtained with the complex rating algorithm used in the standard NDVI MOD13Q1 product. While the data with &lt;strong&gt;climatology&lt;/strong&gt; state (orange points) seems far off.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What does the &lt;em&gt;climatology&lt;/em&gt; attribute mean and how to treat it?&lt;/p&gt;&#xA;" OwnerUserId="2511" LastEditorUserId="2511" LastEditDate="2017-04-03T13:32:40.647" LastActivityDate="2017-04-09T23:25:06.157" Title="MODIS Surface Reflectance Data State QA Aerosol Quantity field meaning is unclear" Tags="|remote-sensing|modis|ndvi|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10047" PostTypeId="5" CreationDate="2017-04-03T11:39:10.530" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2017-04-03T11:39:10.530" LastActivityDate="2017-04-03T11:39:10.530" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10048" PostTypeId="4" CreationDate="2017-04-03T11:39:10.530" Score="0" Body="MODIS is a multispectral satellite sensor on board of NASA Terra and Aqua satellites. MODIS data products are widely used in Earth Science." OwnerUserId="2511" LastEditorUserId="2511" LastEditDate="2017-04-03T14:19:44.547" LastActivityDate="2017-04-03T14:19:44.547" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10049" PostTypeId="2" ParentId="7430" CreationDate="2017-04-03T14:15:53.270" Score="2" Body="&lt;p&gt;The visible emissions from atomic oxygen take place between the fine structure levels of the ground state, and transitions between these states are not quantum-mechanically allowed by electric-dipole radiation. These &quot;forbidden&quot; transitions take much more time to occur, proceeding by magnetic dipole or electric-quadripole radiation. As a result the atom spends a long time in the excited state (~1sec for the 557.7 nm transition, and ~200 s for the 630 nm transition), during which time the atom can make collisions and deactivate without radiating. However, the emissions from molecular nitrogen take place between dipole-allowed transitions, and spend only ns to micro-seconds in the excited state before radiating. Thus, they survive to radiate even in high collision conditions (i.e. low altitudes).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The frequency of collisions an atom or molecule makes increases with decreasing altitude. In addition, the higher the energy of the auroral electrons (2 keV to 20 keV), the lower in the atmosphere they deposit the energy (150 km to 90 km). If there are low energy electrons in the aurora, the emission occurs at very high altitude and both the excited atomic oxygen and the molecular nitrogen make few collisions. Thus they both radiate, but at these altitudes there is more atomic oxygen than molecular nitrogen and the reds and greens of atomic oxygen dominate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the auroral energies increase and the electrons deposit their energy at lower altitudes, collisions are much more frequent and the atomic oxygen excited states do not live long enough to radiate. This kills off the green and red emissions at low altitudes. However, the molecular nitrogen, with its short excited state lifetimes, continues to radiate and the lower border of the aurora turns pinkish-purple with the nitrogen emissions.&lt;/p&gt;&#xA;" OwnerUserId="7845" LastActivityDate="2017-04-03T14:15:53.270" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10050" PostTypeId="2" ParentId="10045" CreationDate="2017-04-03T18:02:35.643" Score="13" Body="&lt;p&gt;the trick is not all isolated rocks are produced the same ways. Of the two in your pictures  the first is an old volcanic events; intrusions, dikes, ect. depending on which rock in the region you are talking about. The whole deccan plateau region is full of them, some have been exposed on the surface via erosion. Basically everything else eroded faster than they did leaving them sticking out. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/0jHGi.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0jHGi.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second was produced by the same effect (eroding slower than the rock around it) but this time it was just a hard massive sandstone formation surrounded by more easily eroded rock. It is part of the bedrock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rMzCC.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rMzCC.jpg&quot; alt=&quot;http://uluru-katatjuta-information-page.weebly.com/uploads/2/0/3/2/20321131/4518517_orig.jpg&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2017-04-03T18:02:35.643" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10051" PostTypeId="2" ParentId="10033" CreationDate="2017-04-04T04:53:48.130" Score="1" Body="&lt;p&gt;What the heck is an &quot;earth pigment&quot;? Dirt? Mud? The only naturally occurring &quot;earth pigment&quot; that I am aware of is used for adobe buildings of the American Southwest. Here, the &quot;earth pigment&quot; is taken from a riverbed and applied directly to adobe brick. It will not fade in sun. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it tends to run when it rains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand...there are plenty of earth-colored dyes that are added to concrete mixes that will mimic mud and earth when applied as stucco. I can assure you that these, over time, will fade. UV radiation, ozone exposure, ground-level smog, and other general atmospheric crap will noticeably degrade these colors in a matter of years depending on where you live and weather exposure. In Arizona, for example, there is no shortage of stuccos colored with lousy &quot;earth colored&quot; dyes. Your &quot;lime wash&quot; application may respond very differently to your dye and water chemistry, and I'd strongly suggest a test surface before committing to an entire heritage building.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fading, additionally, will be uneven where water, or sunlight, is unevenly distributed over a large surface. As for your &quot;ochre&quot; pigment, I suspect that it's not a powder ground from just straight up iron-oxide, but some kind of liquid ochre-colored emulsion specially formulated for mixture with concrete. Get an assurance that your boss's &quot;earth color&quot; dye, or additive, is lightfast, at a minimum. &lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-04-04T04:53:48.130" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10052" PostTypeId="2" ParentId="10038" CreationDate="2017-04-04T11:42:22.737" Score="4" Body="&lt;p&gt;&lt;strong&gt;Why are cumulus the only basic cloud type to favor lightning?&lt;/strong&gt;&lt;br&gt;&#xA;Because the speed of rising in the updraft is fundamental to lightning formation, as shown by this example plot from &lt;a href=&quot;http://www.goes-r.gov/resources/Scipubs/docs/2008/2007JD009598.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Total lightning activity as an indicator of updraft characteristics by Deierling and Petersen&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FMEqQ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FMEqQ.png&quot; alt=&quot;updraftvslightning&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The faster the air rises, the more lightning in makes.  Only rapid updrafts can separate charges fast enough to overcome dissipation and build up the &lt;a href=&quot;http://hyperphysics.phy-astr.gsu.edu/hbase/electric/lightning2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;hundreds of millions of Volts&lt;/a&gt; (related &lt;a href=&quot;https://electronics.stackexchange.com/questions/10909/lightning-bolt-vs-batteries-a-coulomb-in-everyday-terms&quot;&gt;ESE question&lt;/a&gt;) needed for lightning.  Out of the three standard cloud categories, only cumulus involves significant vertical motion.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Other cloud types?&lt;/strong&gt;&lt;br&gt;&#xA;First off, &lt;strong&gt;nearby clouds of other types can mask the cumulus structure responsible for the lightning&lt;/strong&gt;.  Very commonly in strong storm environments, the broad widespread rising motion, especially near the warm front, can cause a thick low-level stratus deck to form.  And sometimes, in situations where dynamic forcing is dominant (such as with upper-level storm systems), or where storms move into a new environments (such as lake effect snow storms), fog can be thick, such that basically nothing can be seen!  So in those situations, its hard to truly attribute the lightning to the cumulonimbus, despite that being the cause.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plus, full storm cells often develop fairly complex structures:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Lbjtd.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Lbjtd.png&quot; alt=&quot;supercell&quot;&gt;&lt;/a&gt;(Wikipedia, credit Kelvinsong)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Due to their shape and motions, &lt;strong&gt;some parts of storms might reasonably be categorized as stratus or altostratus, though they stem from a larger (past or present) cumulonimbus structure&lt;/strong&gt;. These stratus-like components include &lt;a href=&quot;https://en.wikipedia.org/wiki/Arcus_cloud&quot; rel=&quot;nofollow noreferrer&quot;&gt;arcus&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Cumulonimbus_incus&quot; rel=&quot;nofollow noreferrer&quot;&gt;incus&lt;/a&gt;, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Cumulonimbus_velum&quot; rel=&quot;nofollow noreferrer&quot;&gt;velum&lt;/a&gt;.  And &lt;a href=&quot;http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/cld/cldtyp/oth/mm.rxml&quot; rel=&quot;nofollow noreferrer&quot;&gt;mammatus clouds&lt;/a&gt; that can occur as part of strong storms are actually a unique example of clouds with sinking air.  Even though air in these regions isn't rising much, leftover charge from nearby (or past) updrafts can still bring about lightning.  &lt;a href=&quot;https://www.google.com/search?q=youtube%20anvil%20crawlers&amp;amp;ie=utf-8&amp;amp;oe=utf-8#tbm=vid&amp;amp;q=anvil%20crawlers&amp;amp;*&quot; rel=&quot;nofollow noreferrer&quot;&gt;Anvil crawlers&lt;/a&gt; are a common lightning seen in the fairly flat upper regions of storms.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, while more precise cloud classifications do now set the stages of growing thunderstorms clouds into the cumulonimbus genus, the nimbus prefix &lt;a href=&quot;http://www.etymonline.com/index.php?term=nimbus&amp;amp;allowed_in_frame=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;classically meant precipitating&lt;/a&gt; (raining/hailing/snowing).  &lt;strong&gt;Precipitation reaching the ground is not an absolute requirement for a storm cloud to produce lightning&lt;/strong&gt;.  So in a loose sense, a cloud doesn't truly have to be a cumulo&lt;em&gt;nimbus&lt;/em&gt;, at least historically.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And of course, as it can do with just about any non-insulating material, &lt;strong&gt;lightning can pass through inactive clouds&lt;/strong&gt; on the journey to the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;But while these situations may technically satisfy your search for lightning in other clouds types, you're fundamentally right, standard lightning generally derives from cumuloform cloud origins.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="-1" LastEditDate="2017-04-13T12:33:09.780" LastActivityDate="2017-04-04T22:14:32.690" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10055" PostTypeId="1" CreationDate="2017-04-05T06:28:46.520" Score="3" ViewCount="676" Body="&lt;p&gt;I am restricting my consideration, for the moment, to just the troposphere. With regard to our understanding of the GHE do we predict that an increased GHE due to increasing CO2/Water/Methane will change the lapse rate postively or negatively? The dry adiabatic lapse rate (DALR), according to my old text books, is easily calculated from the formulae -g/c, where g is the acceleration due to gravity and c is the specific heat capacity of the atmosphere. This is supposed to be a general formulae that can be applied to any planet with a solid surface and a gaseous atmosphere. So for earth is the formulae now -g/c + (GHE) or is it -g/c - (GHE)? The bracketed GHE term being specific to the atmosphere of a specific composition, e.g. including 400ppm CO2. &#xA;The second part of the question then , after we have the correct sign, is how is the term (GHE) expected to vary as the CO2 (or other greenhouse gas) concentrations vary? &lt;/p&gt;&#xA;" OwnerUserId="7733" LastActivityDate="2017-04-14T20:57:50.683" Title="How does the existence of a Greenhouse Gas Effect (GHE) in the atmosphere affect the tropospheric lapse rate?" Tags="|climate|climate-change|" AnswerCount="1" CommentCount="1" ClosedDate="2017-04-20T13:08:08.637" ContentLicense="CC BY-SA 3.0" />
  <row Id="10056" PostTypeId="2" ParentId="9818" CreationDate="2017-04-05T07:07:59.327" Score="3" Body="&lt;p&gt;Initial theories of the atmosphere assumed that it was &quot;well mixed&quot;. You will see that term mentioned in many articles, and also the fairly made point that it is an assumption. Historical measurements of CO2 concentration had been pretty sporadic with the exception of Mauna Loa. It's instructive to look at the raw data from that observatory and the adjustments made to produce a smooth curve to view changes year by year. Note also the daily variations due to plants. A NASA satellite was launched in 2014 to measure CO2 high in the atmosphere so there is now evidence CO2 is not well mixed but we do not have enough data to look at long term trends as it has not given us even 3 years worth of data yet.&#xA;It seems to be claimed that about 40% of the CO2 produced from burning fossil fuels comes to show itself as CO2 concentration increases. The rest must go somewhere else (or we got the calculation wrong !). It is often assumed 30-40% goes into the oceans. Although I have seen claims that the earth has greened by about 18% in the past 40 years (increased intensive agriculture) I have not seen the increased CO2 from this source taken into account yet in calculating which proportion of the CO2 increase in the atmosphere is due to that. At a first examination this would seem to be quite important. If the 18% greening is responsible for a significant percentage of CO2 increase then clearly fossil fuel CO2 is less important. This looks like an important area that needs to be looked at. Maybe careful study of satellite data over green areas compared to deserts/ice will reveal something.   &lt;/p&gt;&#xA;" OwnerUserId="7733" LastActivityDate="2017-04-05T07:07:59.327" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10058" PostTypeId="1" CreationDate="2017-04-05T11:05:54.777" Score="6" ViewCount="79" Body="&lt;p&gt;I'm interested in issues related to Global warming and therefore started to read about it from this website --&gt; &lt;a href=&quot;http://www.nmsea.org/Curriculum/Primer/Global_Warming/fossil_fuels_and_global_warming.htm&quot; rel=&quot;noreferrer&quot;&gt;Link&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I was reading I got stuck in the third paragraph of &lt;code&gt;What are Greenhouse gas ?&lt;/code&gt; section. It says &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Secondly, CO2 tends to remain in the atmosphere for a very long time (time scales in the hundreds of years). Water vapor, on the other hand, can easily condense or evaporate, depending on local conditions. Water vapor levels therefore tend to adjust quickly to the prevailing conditions, such that the energy flows from the Sun and re-radiation from the Earth achieve a balance. CO2 tends to remain fairly constant and therefore behave as a controlling factor, rather than a reacting factor. More CO2 means that the balance occurs at higher temperatures and water vapor levels. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I do not understand the whole paragraph and also specially the controlling and reacting factor. Please help .Thankyou in advance. &lt;/p&gt;&#xA;" OwnerUserId="7852" LastActivityDate="2017-04-11T10:05:02.713" Title="What is meant by controlling and reacting factor?" Tags="|climate-change|terminology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10059" PostTypeId="2" ParentId="10046" CreationDate="2017-04-05T11:19:39.897" Score="5" Body="&lt;p&gt;Most likely, climatology means there was &lt;em&gt;no retrieval at all&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bayesian retrievals combine information from an &lt;em&gt;a priori&lt;/em&gt; with information from measurements.  When the retrieval fails for whatever reason, or the measurement contains insufficient information, instead of reporting no measurement at all, they copy over information from the &lt;em&gt;a priori&lt;/em&gt; and use the flag to indicate that the reported &quot;measurement&quot; is in fact simply the climatology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For details, see &lt;a href=&quot;https://en.wikipedia.org/wiki/Optimal_estimation&quot; rel=&quot;noreferrer&quot;&gt;optimal estimation&lt;/a&gt;, in particular the book by Rodgers:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clive D. Rodgers (2000). Inverse Methods for Atmospheric Sounding: Theory and Practice. World Scientific.&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2017-04-05T11:19:39.897" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10060" PostTypeId="2" ParentId="10058" CreationDate="2017-04-05T11:51:13.420" Score="4" Body="&lt;p&gt;A &lt;em&gt;controlling factor&lt;/em&gt; is a factor that acts as a cause for others.  A &lt;em&gt;reactive factor&lt;/em&gt; is rather the consequence: that which &lt;em&gt;reacts&lt;/em&gt; to the controlling factor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, the Sun is certainly a controlling factor.  Nothing we do influences what happens on the Sun, but what happens on the Sun certainly influences us very strongly.  Fortunately, its total power output is quite stable so as far as climate is concerned, we don't need to worry about it too much as far as the next couple of million years are concerned (although eventually, in hundreds of millions to billions of years, increasing power from the Sun will render the Earth uninhabitable).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;CO₂ is both a controlling and a reactive factor.  We add CO₂ to the atmosphere, so the CO₂ concentration reacts to our emissions (reactive factor).  But CO₂ levels are also a cause.  If you were to make a simple climate model, you would put in the CO₂ concentration as a fixed value or perhaps an increasing value as a function of time: in such a model, it would be a boundary condition.  If you instead made a model of a single factory or car and modelled how changes in the fuel cycle would affect CO₂ emissions, then those would instead be a reactive factor.  It all depends on the context.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For H₂O, however, it makes no sense to put in a fixed version as a boundary condition.  Its concentration varies rapidly on short timescales: today may be dry and tomorrow a wet airmass may get in.  Of course, physically, H₂O causes even more of the greenhouse effect than CO₂, but the increase of H₂O is not what is &lt;em&gt;causing&lt;/em&gt; anthropogenic climate change; if anything, an increase in H₂O is one of the effects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, think of it as a system: you add CO₂ (cause), many things happen, including an increase in H₂O in some places (effect).  The cause is the &lt;em&gt;controlling factor&lt;/em&gt;.  The effect is the &lt;em&gt;reactive factor&lt;/em&gt;, even though physically, both CO₂ and H₂O are strongly contributing greenhouse gases.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2017-04-11T10:05:02.713" LastActivityDate="2017-04-11T10:05:02.713" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10061" PostTypeId="1" CreationDate="2017-04-05T10:18:58.570" Score="1" ViewCount="21" Body="&lt;p&gt;I'm interested in issues related to Global warming and therefore started to read about it from this website --&gt;&gt; &lt;a href=&quot;http://www.nmsea.org/Curriculum/Primer/Global_Warming/fossil_fuels_and_global_warming.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;As I was reading I got stuck in the third paragraph of &lt;code&gt;What are Greenhouse gas ?&lt;/code&gt; section. It says &lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Secondly,  CO2 tends to remain in the atmosphere for a very long time (time scales in the hundreds of years). Water vapor, on the other hand, can easily condense or evaporate, depending on local conditions. Water vapor levels therefore tend to adjust quickly to the prevailing conditions, such that the energy flows from the Sun and re-radiation from the Earth achieve a balance. CO2 tends to remain fairly constant and therefore behave as a controlling factor, rather than a reacting factor. More CO2 means that the balance occurs at higher temperatures and water vapor levels. &#xA;  &lt;br&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I do not understand the whole paragraph and also specially the controlling and reacting factor.&#xA;Please help .Thankyou in advance. &lt;/p&gt;&#xA;" OwnerUserId="7852" OwnerDisplayName="Yogesh Tripathi" LastActivityDate="2017-04-05T12:17:54.377" Title="What is meant by controlling and reacting factor?" Tags="|terminology|atmospheric-chemistry|" AnswerCount="0" CommentCount="3" ClosedDate="2017-04-05T13:45:02.700" ContentLicense="CC BY-SA 3.0" />
  <row Id="10062" PostTypeId="1" AcceptedAnswerId="10064" CreationDate="2017-04-05T17:25:48.237" Score="6" ViewCount="883" Body="&lt;p&gt;If a person is to stand at the epicenter of an earthquake. Is it true that he would not detect P-waves nor S-waves echoing off the mantle core boundary? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since if P-wave that enter perpendicularly into the core is not refracted or reflected and S-waves are absorbed by the liquid outer core?&lt;/p&gt;&#xA;" OwnerUserId="7854" LastEditorUserId="2536" LastEditDate="2017-04-06T11:40:18.810" LastActivityDate="2017-04-06T15:22:08.273" Title="seismic wave detection standing at the epicenter" Tags="|earthquakes|seismology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10063" PostTypeId="2" ParentId="9745" CreationDate="2017-04-05T22:09:33.083" Score="13" Body="&lt;p&gt;The glacial buzzsaw hypothesis (&lt;a href=&quot;https://www.newscientist.com/article/mg22430002-500-glacial-buzz-saw-takes-mountains-out-at-the-knees/&quot; rel=&quot;noreferrer&quot;&gt;summary&lt;/a&gt;; &lt;a href=&quot;http://duff.ess.washington.edu/grg/publications/pdfs/QR2006_Mitchell.pdf&quot; rel=&quot;noreferrer&quot;&gt;sample paper&lt;/a&gt;) is that mountains can't get much higher than the elevation at which glaciers form cirques. The upper walls of the cirques are steep and erode easily, which planes off the peaks above them, shortening the mountains. The evidence is, to summarize, that they &lt;em&gt;don't&lt;/em&gt; get much higher than the cirques. Cirques are lower in higher latitudes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The highest possible mountain would therefore, I imagine, be near the equator and somewhere quite dry to minimize glaciation. But a very high mountain intrinsically alters global wind and weather patterns -- the Himalayas are sometimes called &quot;the third pole&quot;. I don't know if you &lt;em&gt;could&lt;/em&gt; have a dry, tallest-in-the-world mountain near the equator, no matter what plate tectonics was trying to do.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;NEW PAPER/SUMMARY:&#xA;Dielforder et al., 2020, (&lt;a href=&quot;https://arstechnica.com/science/2020/06/plate-tectonics-vs-erosion-what-sets-the-height-of-a-mountain-range/&quot; rel=&quot;noreferrer&quot;&gt;summary&lt;/a&gt;; &lt;a href=&quot;https://www.nature.com/articles/s41586-020-2340-7&quot; rel=&quot;noreferrer&quot;&gt;paper&lt;/a&gt;) did a analysis/simulation of all the tectonic pressures that push mountains higher or squash them (or the crust they're on) lower under their own weight. They find that the tectonic pressures alone predict mountain heights pretty well, without paying attention to climate/glaciation. This implies that mountains are just as tall as tectonics makes them -- if glaciation buzzes off the top, the tectonics just squeeze them up to the previous height. Various kinds of erosion would determine the shape of the mountain, but not its size. &lt;/p&gt;&#xA;" OwnerUserId="2639" LastEditorUserId="2639" LastEditDate="2020-06-16T19:46:43.523" LastActivityDate="2020-06-16T19:46:43.523" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="10064" PostTypeId="2" ParentId="10062" CreationDate="2017-04-06T11:37:39.613" Score="3" Body="&lt;p&gt;A person would not detect much else than the surface waves (Love and Rayleigh waves). The later body waves phases are of very low amplitude and are only detected by a sensitive seismometer. Also, at a short offset, it is often hard to pick later phases, even if they occur. There is a critical angle for seismic &lt;a href=&quot;https://en.wikipedia.org/wiki/Seismic_refraction&quot; rel=&quot;nofollow noreferrer&quot;&gt;refraction&lt;/a&gt;, but not for &lt;a href=&quot;https://en.wikipedia.org/wiki/Reflection_seismology&quot; rel=&quot;nofollow noreferrer&quot;&gt;reflection&lt;/a&gt;. 0-offset reflection originates just beneath the source. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The core-mantle boundary represent a large change in elastic properties, so some energy will bounce back to the surface. We call these &lt;a href=&quot;http://www.isc.ac.uk/standards/phases/&quot; rel=&quot;nofollow noreferrer&quot;&gt;phases&lt;/a&gt; &lt;em&gt;PcP&lt;/em&gt;, &lt;em&gt;ScP&lt;/em&gt; and &lt;em&gt;ScS&lt;/em&gt; phases (Pressure-core-Pressure etc). The PcP is the reflected P-wave and ScS is the reflected S-wave. The ScP wave is an interesting phenomena, as it's formed as a part of the energy in the S-wave is converted into a P wave and reflected. There are also higher orders of seismic wave phases that can be detected (or modelled in synthetic seismograms) near the epicenter, the PcP2 and ScS2 e.g. (not shown in figure). The PKiKP is a reflection from the inner core. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qK3Tz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qK3Tz.png&quot; alt=&quot;P&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The travel time diagram gives a rather good idea of when to expect seismic phases at different distances from the earthquake. The distance is in degrees, so 180$^\circ$ is on the opposite side of the planet. Note how the core shields all direct shear waves, that is why we know that the outer core is fluid. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-04-06T15:22:08.273" LastActivityDate="2017-04-06T15:22:08.273" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10065" PostTypeId="2" ParentId="10038" CreationDate="2017-04-06T14:50:48.623" Score="4" Body="&lt;p&gt;I would like to extend the answer by Jeopardy Tempest and provide an alternate view of other clouds that can discharge lightning and this answer will focus more on the observational view of lightning. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most recent review on this subject can be found in this excellent book &#xA;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2004EO110009/pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lightning Physics And Effects by Vladimir Rakov and Martin Uman&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general cloud bases usually have negative charge and when you have cloud to ground discharge from the base of the cloud that is called as negative lightning and when the discharge happens from the top of the cloud (which is positively charged) that is called positive lightning. There exists an electrical dipole between the top and base of the cloud. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am going to describe three other cases where electrical discharge and lightning have been observed apart from the cumulonimbus case &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;1) Stratiform precipitation from mesoscale convective complexes(MCC)&lt;/strong&gt;&#xA;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/95JD03764/epdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Electric field measurements above mesoscale convective systems&lt;/a&gt; From this paper the authors report two luminous features above MCCs namely red sprites and blue jets. Sprites usually occur above the stratiform cloud that trail the convective line in MCCs. Their measurements  are basically electric field magnitudes and they conclude that discontinuities in the electric field above MCCs were caused by positive cloud-to-ground lightning flashes.These  positive ground flashes were detected by  the National Lightning Detection Network within  1 s of  the electric field  discontinuity seen above the cloud  with  the  balloon-borne  electric  field  meter.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2000JD900640/pdfhttp://onlinelibrary.wiley.com/doi/10.1029/2000JD900640/pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Voltages inside and just above thunderstorms&lt;/a&gt; This following  study  concludes that lightning contributions from mesoscale convective complexes(MCS) stratiform clouds  and thunderstorm anvils does contribute to the overall global electrical circuit and the average cloud top voltage was +32 million volts above two MCS stratiform clouds and above a thunderstorm anvil. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;2)Stratus, Stratocumulus and  Nimbostratus&lt;/strong&gt; - &#xA;&lt;a href=&quot;https://ia800308.us.archive.org/7/items/nasa_techdoc_19720018839/19720018839.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Electricity of Clouds by Imyanitov et al.&lt;/a&gt; Imyanitov's pioneering work in the early 1970s in Russia done with aircraft reveal that charge density of Stratus, Stratocumulus and Nimbostratus are comparable to those of thunderclouds. Pilots have reported damage by lightning in non thunderstorm clouds such as nimbostratus and altostratus. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;3) Winter lightning&lt;/strong&gt; - Has lightning been observed  during winter storms ? &#xA;It would seem somewhat contrary to  the conventional view is that lightning is a phenomenon associated with the season of summer. However in Japan several cases of winter lightning have been studied using radar echoes as shown in this reference - &lt;a href=&quot;https://www.jstage.jst.go.jp/article/jmsj1965/71/2/71_2_195/_pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;A Study of Radar Echoes and their Relation to Lightning Discharges of Thunderclouds in the Hokuriku District&#xA;Part II: Observation and Analysis of &quot;Single-Flash&quot; Thunderclouds in Midwinter&lt;/a&gt; and these are the conclusions &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ol&gt;&#xA;  &lt;li&gt;For the generation of lightning discharges, the cloud top has to develop high enough in the troposphere;specifically, the 30 dBZ echo of the clouds has to develop higher than the -20℃ temperature level.&lt;/li&gt;&#xA;  &lt;li&gt;For the generation of lightning discharges, there has to exist a sufficient altitude of the -10℃ temperature level from the ground where precipitation&#xA;  particles are formed and electrified; specifically, it should be at least 1.4km.&lt;/li&gt;&#xA;  &lt;li&gt;For the generation of lightning discharges, the clouds have to involve rapid development of graupel precipitation; specifically, they have to involve formation and vertical movement of 40-to-50 dBZ echo cells&lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;When the altitude of the -10 C temperature level is below 1.4 kms no lightning activity is observed and the above reference also mentions  that a Japanese aircraft that took off on 29th January 1991(during boreal winter) was stuck by lightning as it &quot;invaded&quot; convective clouds. However these are weak flashes and are known as &quot;Single Flash&quot; thunderstorms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;4) Can a tropical hurricane discharge lightning flashes ?&lt;/strong&gt; It has certainly been observed in Hurricane Andrew&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/94JD00722/full&quot; rel=&quot;nofollow noreferrer&quot;&gt; Cloud to ground lightning in Hurricane Andrew&lt;/a&gt; and the authors report that positive eye wall flashes have been reported from the cloud tops in addition to negative eye wall flashes from the highest eye wall cloud tops. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastActivityDate="2017-04-06T14:50:48.623" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10066" PostTypeId="1" AcceptedAnswerId="13274" CreationDate="2017-04-06T20:13:10.307" Score="13" ViewCount="193" Body="&lt;p&gt;According to Monin-Obukhov similarity theory, Reynolds-averaged surface layer winds can be expressed by $$\frac{\partial \bar{U}}{\partial z}=\frac{u_*\psi_M(\frac{z}{L})}{kz}$$&#xA;The potential temperature can be expressed as$$\frac{\partial \bar{\theta}}{\partial z}=\frac{\theta_*\psi_H(\frac{z}{L})}{kz}$$ and I found one for moisture $$\frac{\partial \bar{q}}{\partial z}=\frac{q_*\psi_q(\frac{z}{L})}{kz}$$My question is whether this could be generalized to a tracer $\chi$ such that $$\frac{\partial \bar{\chi}}{\partial z}=\frac{\chi_*\psi_\chi(\frac{z}{L})}{kz}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If so, would this question the validity of the Gaussian Plume model?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: $u_*, \theta_*, q_*$ and $\chi_*$ are the scaled quantities. $\psi_M, \psi_H, \psi_q,$ and $\psi_\chi$ are the universal functions for each quantity. $k$ is the Von Karman constant.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2017-04-06T20:20:53.117" LastActivityDate="2018-03-05T07:32:19.523" Title="Can Monin-Obukhov Similarity theory be generalized to tracers?" Tags="|turbulence|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10067" PostTypeId="1" CreationDate="2017-04-06T20:18:52.177" Score="6" ViewCount="153" Body="&lt;p&gt;I came across this question in my text book:&#xA;&amp;quot;During a visit to a mountainous area, students noticed a high mountain consists of 3 different parts: The top of the mountain consists of fossiliferous limestone. The middle of the mountain consists of fine grained rocks. The foot of the mountain consists of thick layers of boulder, gravel and tree trunks.&lt;/p&gt;&#xA;&lt;p&gt;Which of those parts belongs to a marine environment? And which belongs to an aerobic environment? And which belongs to a river environment?&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;My attempt at a solution is this:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The top (fossiliferous limestone) -----&amp;gt; marine environment.&lt;/p&gt;&#xA;&lt;p&gt;The middle (fine grained rocks) -----&amp;gt; aerobic environment.&lt;/p&gt;&#xA;&lt;p&gt;The base (boulder, gravel and tree trunks -----&amp;gt; River environment.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I wanted to know if my answer was correct or not, because the answer to the question in the book was:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;the top---&amp;gt; marine environment.&lt;/p&gt;&#xA;&lt;p&gt;the middle---&amp;gt; river environment.&lt;/p&gt;&#xA;&lt;p&gt;the base --&amp;gt; aerobic environment.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Could someone please clarify it for me?&lt;/p&gt;&#xA;" OwnerUserId="6908" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-12-05T21:43:22.323" Title="The environments of particular deposits" Tags="|homework|erosion|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10068" PostTypeId="1" CreationDate="2017-04-07T17:53:08.023" Score="1" ViewCount="2959" Body="&lt;p&gt;If the earth is a globe and the sun is 93 million miles away, why is the equator the hottest place on earth?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of distances to the sun, the distance to the equator is almost equal to that as the distance to the poles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Around January 3, the sun is said to be about 91.4 million miles away, but on July 7, the sun is said to be about 94.5 million miles away. The earth is warmer on July 7 (summer time), and yet it is 3 million miles further than when it is in January, how is this possible?&lt;/p&gt;&#xA;" OwnerUserId="7864" LastEditorUserId="11171" LastEditDate="2017-10-04T16:11:58.697" LastActivityDate="2018-02-22T02:41:02.693" Title="If the earth is a globe, what causes temperature differences across lines of latitude?" Tags="|climate|temperature|" AnswerCount="2" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="10069" PostTypeId="2" ParentId="10068" CreationDate="2017-04-07T17:58:10.820" Score="4" Body="&lt;p&gt;The major reason isn't Earth's distance to the sun. The major reason is that earth's axis is tilted. The Arctic circle, for example, sees 24 hours of darkness in the winter, and 24 hours of sunlight in the summer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you go to the other side of the equator, you'll note that the seasons seem switched- the southern hemisphere is warmer in the winter than in the summer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take a look at how much sunlight each day has- you'll note that in the summer, the northern hemisphere has more hours of sunlight than the winter. The opposite is true for the southern hemisphere.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-04-07T17:58:10.820" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="10070" PostTypeId="1" CreationDate="2017-04-07T18:08:15.417" Score="3" ViewCount="674" Body="&lt;p&gt;Essentially I would like to know how current direction &quot;DIR C&quot; and wind direction &quot;WDIR&quot; for gribs is computed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm trying to compute some angles from u and v vectors in grib files. My understanding from &lt;a href=&quot;https://www.eol.ucar.edu/content/wind-direction-quick-reference&quot; rel=&quot;nofollow noreferrer&quot;&gt;this link&lt;/a&gt; is that:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Positive U component represents wind blowing to (not from) the East (90 degrees). And positive V component is wind to (not from) the North (0 degrees). Is this correct?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In grib files values UGRD &amp;amp; VGRD are stored this way. How does this apply to currents like UOGRD and VOGRD? Is the same convention used as for UGRD and VGRD?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, &lt;em&gt;assuming the vectors are defined the same&lt;/em&gt; (UGRD and UOGRD) I'm calculating current headings like this from the GRIB data:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;$angle = round(atan2($u, $v) * 180 / pi());&#xA;if ($angle &amp;lt; 0) {&#xA;    $angle = 360 + $angle;&#xA;}&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;And wind like this:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;$angle = round(atan2(-1*$u, -1*$v) * 180 / pi());&#xA;if ($angle &amp;lt; 0) {&#xA;    $angle = 360 + $angle;&#xA;}&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The current output looks like this (using u &amp;amp; v values shown):&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;u=1  v=1 45° NE&#xA;u=-1 v=1 315° NW&#xA;u=1 v=-1 135° SE&#xA;u=-1 v=-1 225° SW&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;And wind looks like with the vector being &quot;from&quot; not to:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;u=1 v=1 225° SW&#xA;u=-1 v=1 135° SE&#xA;u=1 v=-1 315° NW&#xA;u=-1 v=-1 45° NE&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Does this look correct?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note:  This atan2(y,x) function calculates the arc tangent of the two variables x and y. It is similar to calculating the arc tangent of y / x, except that the signs of both arguments are used to determine the quadrant of the result. &lt;/p&gt;&#xA;" OwnerUserId="7865" LastEditorUserId="7865" LastEditDate="2017-04-07T21:17:14.573" LastActivityDate="2017-04-07T21:17:14.573" Title="Do U &amp; V vectors differ depending on GRIB layers (wind vs current)?" Tags="|meteorology|wind|weather-forecasting|ocean-currents|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10071" PostTypeId="1" CreationDate="2017-04-07T18:54:21.047" Score="6" ViewCount="213" Body="&lt;p&gt;The website &lt;a href=&quot;https://www.ventusky.com/?p=20.31;-155.35;6&amp;amp;l=clouds&quot; rel=&quot;nofollow noreferrer&quot;&gt;ventusky.com&lt;/a&gt; offers three models to produce cloud estimate: &lt;a href=&quot;https://www.mpimet.mpg.de/en/science/models/icon/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ICON&lt;/a&gt;, &lt;a href=&quot;http://www.nco.ncep.noaa.gov/pmb/products/gfs/&quot; rel=&quot;nofollow noreferrer&quot;&gt;GFS&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Global_Environmental_Multiscale_Model&quot; rel=&quot;nofollow noreferrer&quot;&gt;GEM&lt;/a&gt;. They extract a fractional cloud number, shown in percentage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the &lt;a href=&quot;http://coastwatch.pfeg.noaa.gov/erddap/griddap/NCEP_Global_Best.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ERDDAP portal&lt;/a&gt; to the GFS model (NCEP_Global_Best), the only relevant data regarding clouds is:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;dlwrfsfc (net downward longwave radiation flux, $Wm^{-2}$) &lt;/li&gt;&#xA;&lt;li&gt;dswrfsfc (net downward shortwave radiation flux, $Wm^{-2}$) &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Is there a way to estimate fractional cloud coverage from these two parameters or does GFS offer some other product for global cloud coverage?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a GRIB or other type of portal with an API to access cloud coverage estimates?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Edit:  I tried openDap as suggested, but the help pages are not clear.  And I don't understand the ranges on the time specifications. Let's say I want to look at 22N, 155W (just 1 point) and look at a 24-hour time frame. I tried &lt;a href=&quot;https://rda.ucar.edu/thredds/dodsC/aggregations/g/ds084.1/1/ds084.1-2017/TwoD?lat[88:1:88],lon[820:1:820],time[301950:1:301970],Total_cloud_cover_entire_atmosphere_Mixed_intervals_Average[0:1:0][0:1:0][0:1:0]&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lat 88, lon 820, time 301950-301970 (I just assumed, probably incorrectly that it ends at the current offset from  2015-01-15T00:00:00Z).  But the results are not what I would expect.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any help would be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="7865" LastEditorUserId="2536" LastEditDate="2017-05-22T19:02:22.523" LastActivityDate="2017-05-22T19:02:22.523" Title="How are global cloud cover estimates generated and how is the data accessed?" Tags="|meteorology|measurements|clouds|open-data|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="10072" PostTypeId="2" ParentId="10055" CreationDate="2017-04-08T02:03:16.810" Score="1" Body="&lt;p&gt;For dry adiabatic, you simply ignore the greenhouse gas.   This might sound like a cheat, but it's not.   The dry adiabatic lapse rate doesn't change with temperature or latitude. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a physical explanation, if you consider what the greenhouse gas does, it captures heat and raises the temperature near the Earth's surface, which expands the troposphere and raises the tropopause.   In other words, the troposphere grows taller, so the lapse rate can remain the same and the tropopause moves a little higher up.   This can also be seen in higher and lower latitudes on Earth in that the tropopause is about 5 miles closer to the Earth at the poles than over the equator.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The adiabatic lapse rate is a property of the ideal gas law.  Heat trapping greenhouse gas doesn't affect it because the gas expands accordingly with trapped heat.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The true environmental lapse rate is a bit more complicated as that fluctuates with humidity.   As the Earth warms, absolute humidity should increase but relative humidity should slightly decrease.   A lower relative humidity, on average, should raise the lapse rate slightly (I think), as the dry adiabatic rate is greater than the moist rate.    But this last paragraph take with a grain of salt.   The environmental lapse rate is more complicated.  &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;2 identical planets, with 2 identically thick atmospheres, same c,&#xA;  same g, same lapse rate but one is a pure CO2 atmosphere and the other&#xA;  is a non greenhouse gas with the same c (fictional gas, we will call&#xA;  it CO2U)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm not an expert in lapse rate, so my answer is a little bit of a cheat, but I'll take the thought experiment as best I can.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fictional gas - same density as CO2 (at standard temperature &amp;amp; Pressure &quot;STP&quot;).   Both atmospheres are on planets of identical surface area, with identical gravity and both atmospheres have identical mass and (just to clarify) Identical density at STP.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The atmosphere that traps heat will expand, so it will have a higher troposphere.   Hot gas expands.   Cold gas contracts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the planet without the greenhouse gas will have a troposphere that's 6 miles high, the one with the greenhouse gas and a higher surface temperature will have a troposphere 10 miles high.   The rate of temperature drop can remain consistent at (-g/c) but the hotter planet will have a higher troposphere and a more expanded atmosphere.   That's for the theoretical model anyway.   I don't do real world models.  Those are much harder.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;So the planet with the GHE atmosphere will be hotter at the surface,&#xA;  hotter at any given height in the atmosphere and hotter as a complete&#xA;  body/system (atmosphere+solid planet). Everything is hotter. Errr...&#xA;  what happened to the supposed radiative S-B balance as viewed from&#xA;  space then ?? Radiative input from sun the same, radiative output from&#xA;  the GHE planet now higher&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The energy balance question is a fun one, especially when climate change &quot;skeptics&quot; use it to say &quot;climate change can't possibly be right&quot; - look at the chart they use, more heat leaves the Earth's surface than comes from the sun.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KHETu.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KHETu.png&quot; alt=&quot;https://earthobservatory.nasa.gov/Features/EnergyBalance/images/global_energy_budget_components.png&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthobservatory.nasa.gov/Features/EnergyBalance/page6.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lets ignore that debate for brevity and look at the overall theory of increasing greenhouse gas driven climate change.   The Energy from the sun is same, so, why does Earth get warmer?  The answer is trapped heat.   So, what does this look like from space?   Counter intuitively, from space the Earth looks colder than it did 30/40/50 years ago.  It's giving less thermal radiation into space.   This is because heat is being trapped in the lower atmosphere and oceans.  The upper atmosphere on Earth is actually cooling and contracting and less thermal radiation is leaving the Earth, not more, even with the warming surface temperature.  Measuring the decrease in heat that leaves the Earth is one way to measure the total amount of heat being trapped by climate change.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In time, a new equilibrium will eventually be reached and heat in will equal heat out again but for now on Earth, Heat in is greater than heat out.  The difference is heat added, which does things like warm the air, the oceans and melts the ice.   In your scenario, there's no change, it's already warmer, but it's warmer in equilibrium, so heat in = heat out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words:  A warmer atmosphere at equal heights doesn't mean more heat leaves the planet, because the CO2 rich atmosphere makes it harder for the thermal radiation from the warm surface to reach space.   The greater heat is balanced out by a greater percentage being reflected back to the surface.   The amount that goes into space is equal on the 2 planets.   &lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2017-04-14T20:57:50.683" LastActivityDate="2017-04-14T20:57:50.683" CommentCount="14" ContentLicense="CC BY-SA 3.0" />
  <row Id="10073" PostTypeId="2" ParentId="10068" CreationDate="2017-04-08T02:13:13.450" Score="18" Body="&lt;p&gt;Polar regions are colder than equatorial ones for a simple reason - geometry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More specifically, it is caused by the greater angle of the Sun's rays to the surface of the Earth. As you go farther north, the Earth's (mostly) spherical surface bends back from the direction of the Sun's rays, and the same amount of photons are spread over a larger area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What's more, the closer you get to the poles, this already-attenuated sunlight has to go through more of the Earth's atmosphere, and so more sunlight is &lt;a href=&quot;http://en.wikipedia.org/wiki/Rayleigh_scattering&quot; rel=&quot;noreferrer&quot;&gt;scattered&lt;/a&gt;, and consequently less will reach the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's an image (Thanks, Pont) to show the difference:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/WfajV.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WfajV.png&quot; alt=&quot;Insolation at different latitudes&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Oblique_rays_04_Pengo.svg&quot; rel=&quot;noreferrer&quot;&gt;Wikimedia Commons&lt;/a&gt;. License: CC BY-SA 3.0&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sun's angle is more important to climate differences than the modest variation in Earth's distance to the sun, because the atmosphere is kept warm by the &lt;a href=&quot;http://en.wikipedia.org/wiki/Greenhouse_effect&quot; rel=&quot;noreferrer&quot;&gt;greenhouse effect&lt;/a&gt;. It's not the direct light that matters: Air is more or less transparent to the visible light that makes up most of the Sun's spectrum. Instead, the ground absorbs that light and reradiates it as infrared and microwave radiation. That longer-wavelength radiation is absorbed by the atmosphere, but if the ground is not radiating as much infrared because it absorbed less sunlight, the atmosphere above it doesn't get warmed quite so much.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Granted, if the Earth's orbit were much more eccentric then the variation in distance to the Sun would matter more to climate variation. But it doesn't.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This would happen even if Earth's axis weren't tilted. Polar regions would still be cold and equatorial regions would still be hotter. In fact, the difference would be greater because there'd be less mixing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The image below shows the what happens to the energy the Earth receives from the Sun:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/m5ZXz.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/m5ZXz.png&quot; alt=&quot;Earth&amp;#39;s energy budget&quot;&gt;&lt;/a&gt;&lt;sup&gt;Source: &lt;a href=&quot;https://earthobservatory.nasa.gov/Features/EnergyBalance/page6.php&quot; rel=&quot;noreferrer&quot;&gt;NASA&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That shows an average over the entire Earth. As you approach the poles, the percentage &quot;reflected by clouds and atmosphere&quot; goes up while total energy &quot;absorbed by surface&quot; per unit area goes down. And since ice has a high albedo, this is reinforced by the percentage &quot;reflected by surface&quot;.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2017-04-15T21:21:23.870" LastActivityDate="2017-04-15T21:21:23.870" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10074" PostTypeId="1" CreationDate="2017-04-08T13:03:51.887" Score="3" ViewCount="4674" Body="&lt;p&gt;In any geological plane, strike gives the direction of a line formed by intersection of horizontal plane and geological plane. And dip shows the orientation of the geological plane. While studying, I came to know that strike is perpendicular to dip. But when I tried to determine dip from strike, I can not do it. But when I can determine strike when dip is known. So how can we determine dip if strike is known?&lt;/p&gt;&#xA;" OwnerUserId="7870" LastActivityDate="2017-07-05T05:18:06.973" Title="Can we determine strike when dip is given? What about the reverse?" Tags="|geology|structural-geology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10075" PostTypeId="1" AcceptedAnswerId="10076" CreationDate="2017-04-08T17:37:59.363" Score="3" ViewCount="260" Body="&lt;p&gt;Approaching the end of the Cretaceous period, where on the planet (latitude and longitude) was Cornwall, England? .. Approximately. &lt;/p&gt;&#xA;" OwnerUserId="7872" LastActivityDate="2017-04-09T18:49:40.850" Title="At what latitude/longitude was Cornwall, England 75 million years ago?" Tags="|paleogeography|cretaceous|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10076" PostTypeId="2" ParentId="10075" CreationDate="2017-04-08T21:36:50.900" Score="3" Body="&lt;p&gt;The rocks that make up Britain have been slowly drifting north over geologic time.  About 700 million  years ago it was near the South Pole!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I paused &lt;a href=&quot;https://youtu.be/5yVfJGNjok0&quot; rel=&quot;nofollow noreferrer&quot;&gt;this Youtube video&lt;/a&gt; at 75 mya, held the end of a toothpick over Cornwall, then played it to the end keeping the toothpick steady over that point, under which the approximate location of Bilbao, Spain eventually slid itself. Bilbao is at 43°15′25″N &lt;a href=&quot;http://en.wikipedia.org/wiki/Bilbao&quot; rel=&quot;nofollow noreferrer&quot;&gt;according to Wikipedia&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So now, think of how longitude is defined: Relative to the meridian through Greenwich. A cursory glance at the video I linked to shows the rocks that make up Great Britain have moved as a unit and haven't rotated appreciably over the last 75 million years. So the longitudes associated with Cornwall haven't changed much in that time. &lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2017-04-09T18:49:40.850" LastActivityDate="2017-04-09T18:49:40.850" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10077" PostTypeId="1" CreationDate="2017-04-08T23:01:04.323" Score="5" ViewCount="424" Body="&lt;p&gt;I found these rocks in the Oregon Coast Range many years ago and have always wondered whether the interesting image was a pseudofossil or an actual fossil.  If it's a pseudofossil, any ideas on how it would form? If it's a fossil, what on earth is it? The image measures about 37 mm at its widest point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for any insight you can provide!&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ThWo1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ThWo1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3stsj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3stsj.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7873" LastEditorUserId="7873" LastEditDate="2017-04-11T03:56:44.970" LastActivityDate="2017-04-13T17:17:54.543" Title="Fossil or Pseudofossil?" Tags="|fossils|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10078" PostTypeId="1" AcceptedAnswerId="10089" CreationDate="2017-04-08T23:28:06.247" Score="2" ViewCount="165" Body="&lt;p&gt;I know ground ozone reduce the photosynthesis rate of vegetation and could lead to increase respiration and hence more CO2 in the atmosphere, contributing to global warming. But what is the opposite? How is climate change affect the production of ozone? Higher temperature means higher ozone production? but also more water vapour in the atmosphere which counteract it?  &lt;/p&gt;&#xA;" OwnerUserId="7482" LastActivityDate="2017-04-10T18:50:14.540" Title="What is the impact of climate change on tropospheric ozone production and vice versa?" Tags="|climate|climate-change|air-pollution|ozone|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10079" PostTypeId="1" CreationDate="2017-04-09T15:40:56.373" Score="9" ViewCount="99" Body="&lt;p&gt;I just saw the Periodic Video &lt;a href=&quot;https://youtu.be/YxsxfsYxA4s&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ozone on Bondi Beach - Periodic Table of Videos&lt;/a&gt; where the impact of Chlorine from CFCs on Ozone is discussed. At around &lt;code&gt;04:00&lt;/code&gt; or so, the adsorption of chlorine on to very small atmospheric ice crystals above the poles, especially the south pole is described. The chlorine is &quot;stored&quot; until hemispheric spring, when the sun releases the chlorine from the ice, so its impact on ozone spikes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My main question is about the ice crystals. What keeps them suspended in the atmosphere for months? Why don't they fall, or participate in precipitation? Are they &quot;hovering&quot; over the pole for the whole winter? How?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Note:&lt;/strong&gt; The video then goes on to discuss a &quot;recent paper&quot; (as of 2011) where the UV light reaching nearer the surface enabled by the ozone &quot;hole&quot; goes on to affect rainfall patterns over Australia. Is this now believed to be significant?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2020-03-03T09:18:32.280" LastActivityDate="2020-03-03T09:18:32.280" Title="How can ice crystals with adsorbed chlorine remain over the south pole all winter?" Tags="|air-pollution|antarctic|ozone|" AnswerCount="0" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="10080" PostTypeId="2" ParentId="10067" CreationDate="2017-04-09T16:19:59.560" Score="1" Body="&lt;p&gt;Because the top layer is marine, you're being asked to think of the sequence being &quot;coastal&quot; in origin, where there is ocean, coastal plain, and inland mountains. In this scenario, two things are happening in tandem: the mountains are eroding and sea level is rising.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the mountain erodes, boulders and cobbles (eroded from steep slopes) bury trees and form coarse conglomerates and source material for the coastal plain deposits, which are the middle unit of your sequence. As sea level rises due to local subsidence or a global sea level rise, the marine environment marches steadily inland depositing sands and then limestones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming no unconformities, yours is a textbook example of a continuous depositional sequence!&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-04-09T16:19:59.560" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10081" PostTypeId="2" ParentId="10077" CreationDate="2017-04-09T17:33:34.243" Score="1" Body="&lt;p&gt;That certainly looks like a fossil, but of what is awfully hard to say.... Here's why:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You've only provided a planar surface and fossils (and their traces) exist in 3-D space. This is important because it helps pin down the entire structure of not only the fossil itself, but whether or not it was deformed over time. Your &quot;fossil&quot; shown here, may be a planar cross section through the fossil, but through which part if the fossil may be impossible to say.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it a radial plane through a soft-body sponge (like a deli slicer cuts through a salami)? Or is it an oblique slice through some swamp plant's seed pod that has been subsequently deformed into a circular shape? Here's where both that 3rd dimension comes into play as does the fabric of the host rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would suggest looking for anything regarding fossils and geology of where you found this rock, narrowing down the particular unit that looks like this one, then seeing if there are any academic papers published that may include fossil descriptions similar to this. Good luck!&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-04-09T17:33:34.243" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10082" PostTypeId="2" ParentId="10074" CreationDate="2017-04-09T17:44:19.313" Score="3" Body="&lt;p&gt;No. Strike is a line value whose direction is referenced with respect to true north. Dip can be &lt;strong&gt;any&lt;/strong&gt; 0-90 degree angle (below horizontal) perpendicular to that line. It must be physically measured in the field....usually by some seriously underpaid graduate lackey.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-04-09T17:44:19.313" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10083" PostTypeId="2" ParentId="10046" CreationDate="2017-04-09T23:25:06.157" Score="2" Body="&lt;p&gt;Gerrit is correct, the climatological setting indicates that the value is filled in (not an actual retrieval).  If you see the &lt;a href=&quot;https://vip.arizona.edu/documents/MODIS/MODIS_VI_UsersGuide_01_2012.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;MODIS Vegetation Index User’s Guide&lt;/a&gt;, it is discussed a few times:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Cloud-free global coverage is achieved by replacing clouds with the historical MODIS time series climatology record (Fig. 5)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In the Climatology Fill case, certain highly dynamic regions may show discrepancies where fill values were used. This is most obvious when missing input tiles are replaced, where edges may be visible. For pixels filled&#xA;  due to high cloud contamination, this fill strategy will perform well.  The fill completes the two VI layers with data. Other layers will contain their respective fill values, except data layer 11 (#1km pix used), which is set to 0, i.e., no good input data.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and they give an example too, for African dust:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/878hu.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/878hu.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-04-09T23:25:06.157" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10087" PostTypeId="1" AcceptedAnswerId="10093" CreationDate="2017-04-10T16:19:34.313" Score="3" ViewCount="260" Body="&lt;p&gt;Looking at the following temperature reconstructions i have two questions (source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:2000_Year_Temperature_Comparison.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia&lt;/a&gt;):  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/B78DR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/B78DR.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Why is the y-axis centered around -0.2 °C?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Why are the consequences of the current temperature increase by +0.4 °C considered so &quot;catastrophic&quot; when the -0.8 °C during the &lt;em&gt;little ice age&lt;/em&gt;  was not?&#xA;Maybe i am mistaken but looking at the chart the current +0.4 °C doesn't seem so much more varying from the median that the -0.8 °C do. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="7879" LastEditorUserId="11908" LastEditDate="2019-03-13T05:19:52.783" LastActivityDate="2019-03-13T05:19:52.783" Title="Current temperature increase VS decrease during the little ice age" Tags="|climate-change|climate|glaciology|statistics|ice-age|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10088" PostTypeId="1" CreationDate="2017-04-10T17:45:42.843" Score="6" ViewCount="2070" Body="&lt;p&gt;I've been looking for the cloud cover estimates provided in the NOAA GFS models.  &lt;a href=&quot;http://www.nco.ncep.noaa.gov/pmb/products/gfs/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This page&lt;/a&gt; discusses all their weather products and one of the few I find that includes cloud cover data &quot;Total Cloud Cover [%]&quot; (variable TCDC) is gfs.t00z.pgrb2.0p25.f006 which you can find in &lt;a href=&quot;http://www.nco.ncep.noaa.gov/pmb/products/gfs/gfs.t00z.pgrb2.0p25.f006.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;its product description&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Upon extracting that file using the &lt;a href=&quot;http://nomads.ncep.noaa.gov/cgi-bin/filter_gfs_0p25.pl?file=gfs.t12z.pgrb2.0p25.f006&amp;amp;lev_10_m_above_ground=on&amp;amp;lev_boundary_layer_cloud_layer=on&amp;amp;lev_convective_cloud_bottom_level=on&amp;amp;lev_convective_cloud_layer=on&amp;amp;lev_convective_cloud_top_level=on&amp;amp;lev_entire_atmosphere=on&amp;amp;lev_entire_atmosphere_%5C%28considered_as_a_single_layer%5C%29=on&amp;amp;lev_high_cloud_bottom_level=on&amp;amp;lev_high_cloud_layer=on&amp;amp;lev_high_cloud_top_level=on&amp;amp;lev_surface=on&amp;amp;all_var=on&amp;amp;leftlon=-160&amp;amp;rightlon=150&amp;amp;toplat=20&amp;amp;bottomlat=30&amp;amp;dir=%2Fgfs.2017041012&quot; rel=&quot;nofollow noreferrer&quot;&gt;grib filter tool generated URL&lt;/a&gt; selecting for the proper layers and variables, this data appears to be just initial values (1 for cloud cover) and 9999 for many of the other values.  I read a lot of &lt;a href=&quot;https://www.americanwx.com/bb/topic/38773-gfs-cloud-cover-what-does-it-mean/&quot; rel=&quot;nofollow noreferrer&quot;&gt;gfs grib &amp;amp; cloud details here&lt;/a&gt; that suggest the .fxxx files like &quot;gfs.t00z.pgrb2.0p25.f006&quot; are &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The cloud % field is probably output from some of the model physics (microphysics I guess) routines, which may not be setup to write out the fields after the very first model time step (the f00 files denote fields after the first model time step, not the actual analysis/initial condition).  We do in fact initialize the cloud condensate field, however&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My question is where are the TCDC cloud data numbers in the GFS grib models?  They don't seem to be in the analysis files (&lt;a href=&quot;http://www.nco.ncep.noaa.gov/pmb/products/gfs/gfs.t00z.pgrb2.0p25.anl.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;gfs.t00z.pgrb2.0p25.anl&lt;/a&gt;) or the FH000 file.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note:  I'm using grib_api tools to read these fields (grib_ls and grib_get).  I've used them successfully for currents and winds, but I can't seem to find the right GFS data for TCDC cloud cover.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;EDIT:  I've been testing the full files from &lt;a href=&quot;http://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;the gfs.t12z.pgrb2.0p25.anl file didn't contain cloud data, so I tried one of the .fxxx files (gfs.t12z.pgrb2.1p00.f384).  There appeared to be fields set, but they were at initial values according to grib_ls tool.  Here's a snippet:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;&lt;pre&gt;&lt;code&gt;[3036] =&amp;gt; 260130      Total ozone  9999&#xA;[3037] =&amp;gt; 228164      Total Cloud Cover  9999&#xA;[3038] =&amp;gt; 228164      Total Cloud Cover  9999&#xA;[3039] =&amp;gt; 228164      Total Cloud Cover  9999&#xA;[3040] =&amp;gt; 228164      Total Cloud Cover  9999&#xA;[3041] =&amp;gt; 54          Pressure    9999&#xA;[3042] =&amp;gt; 54          Pressure    1&#xA;[3043] =&amp;gt; 54          Pressure    9999&#xA;[3044] =&amp;gt; 54          Pressure    1&#xA;[3045] =&amp;gt; 54          Pressure    9999&#xA;[3046] =&amp;gt; 54          Pressure    1&#xA;[3047] =&amp;gt; 54          Pressure    9999&#xA;[3048] =&amp;gt; 54          Pressure    1&#xA;[3049] =&amp;gt; 130         Temperature  1&#xA;[3050] =&amp;gt; 130         Temperature  9999&#xA;[3051] =&amp;gt; 130         Temperature  1&#xA;[3052] =&amp;gt; 228164      Total Cloud Cover  1&#xA;[3053] =&amp;gt; 228164      Total Cloud Cover  1&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm using a little older version of grib_api on my server: 1.10.0&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I get a little different response with grib_api 1.14.4:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;3054        Precipitable water  34.4&lt;br&gt;&#xA;  260102      Cloud water  0&lt;br&gt;&#xA;  157         Relative humidity  39&lt;br&gt;&#xA;  260130      Total ozone  283.1&lt;br&gt;&#xA;  228164      Total Cloud Cover  4&lt;br&gt;&#xA;  228164      Total Cloud Cover  0&lt;br&gt;&#xA;  228164      Total Cloud Cover  5&lt;br&gt;&#xA;  228164      Total Cloud Cover  9&lt;br&gt;&#xA;  54          Pressure    9999&lt;br&gt;&#xA;  54          Pressure    90670.4&lt;br&gt;&#xA;  54          Pressure    9999&lt;br&gt;&#xA;  54          Pressure    13200.4&lt;br&gt;&#xA;  54          Pressure    9999&lt;br&gt;&#xA;  54          Pressure    88060&lt;br&gt;&#xA;  54          Pressure    9999&lt;br&gt;&#xA;  54          Pressure    11470.4&lt;br&gt;&#xA;  130         Temperature  288.9&lt;br&gt;&#xA;  130         Temperature  9999&lt;br&gt;&#xA;  130         Temperature  198.2&lt;br&gt;&#xA;  228164      Total Cloud Cover  0&lt;br&gt;&#xA;  228164      Total Cloud Cover  2&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But it still seems a bit odd for the results.  Lots of 9999's and whole percentages like 0 or 2.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Edit 2:  It appears that computing the cloud cover has to be done from the GFS layer data however it appears how it is done is unclear based on an old message from 2007:  &lt;a href=&quot;http://www.weather-watch.com/smf/index.php/topic,20158.msg216087.html#msg216087&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.weather-watch.com/smf/index.php/topic,20158.msg216087.html#msg216087&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7865" LastEditorUserId="7865" LastEditDate="2017-04-19T21:46:47.160" LastActivityDate="2017-08-14T23:55:42.437" Title="How to find Cloud cover data in GFS grib models" Tags="|meteorology|measurements|clouds|gfs|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="10089" PostTypeId="2" ParentId="10078" CreationDate="2017-04-10T18:50:14.540" Score="2" Body="&lt;p&gt;Since ozone is a greenhouse gas, I would say it would enhance warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/JCLI-D-12-00168.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; explains how regional climate may be impacted by ozone&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2005JD006852/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; says that while global ozone should decrease as a result of warming, ozone over populated areas should increase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Water vapor plays a minute role in the production of tropospheric ozone- it increases the amount of hydroxyl radical to be used in hydroperoxyl formation.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-04-10T18:50:14.540" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10090" PostTypeId="1" CreationDate="2017-04-11T01:40:26.683" Score="7" ViewCount="95" Body="&lt;p&gt;To correlate chemicals in aerosols emanating from certain sample points, backward trajectory analysis is usually applied for identifying the potential geographical source region.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/5mUFl.png&quot; alt=&quot;&quot;&gt;&#xA;In this figure from &lt;a href=&quot;http://www.atmos-chem-phys.net/16/7357/2016/acp-16-7357-2016.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Characteristics of aerosol pollution during heavy haze events in&#xA;Suzhou, China&lt;/a&gt;, the trajectories are clustered into several groups. The different fractions of chemicals (e.g. organic matter, sulfate) in each group shows the impact of different regions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It represents an easy approach  to research the impact of regional transportation for the particulate matter in certain receptors. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The trajectories are calculated for certain times (e.g 0:00, 6:00, 12:00, 18:00 for each day).  &lt;/li&gt;&#xA;&lt;li&gt;Offline PM samples with its chemical species are usually collected for 24 h &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How can I relate the samples with trajectories with different temporal scale?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="595" LastEditDate="2018-06-08T11:12:19.270" LastActivityDate="2018-09-12T09:08:13.520" Title="How to relate the backward trajectories with offline particular samples?" Tags="|atmospheric-chemistry|air-pollution|air-quality|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="10091" PostTypeId="1" CreationDate="2017-04-11T08:00:26.627" Score="2" ViewCount="81" Body="&lt;p&gt;I'm using Matlab to read MODIS Aqua sea surface temperature data. Unfortunately I am not able to do it. It will be great if any of you can help me with that.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;ncread('A2010091081000.L2_LAC_SST.x.nc','sst');&#xA;Error using internal.matlab.imagesci.nc/getGroupAndVarid (line 2083)&#xA;Could not find variable or group 'sst' in file.&#xA;Error in internal.matlab.imagesci.nc/read (line 593)&#xA;            [gid, varid] = getGroupAndVarid(this, location);&#xA;Error in ncread (line 58)&#xA;vardata = ncObj.read(varName, varargin{:})*;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="7884" LastEditorUserId="106" LastEditDate="2017-04-11T08:19:15.683" LastActivityDate="2017-04-11T08:19:15.683" Title="Unable to read modis sst netcdf file in matlab" Tags="|matlab|netcdf|modis|" AnswerCount="0" CommentCount="0" ClosedDate="2017-04-11T22:16:13.620" ContentLicense="CC BY-SA 3.0" />
  <row Id="10092" PostTypeId="1" CreationDate="2017-04-11T08:50:42.730" Score="5" ViewCount="95" Body="&lt;p&gt;Why is ignimbrite associated with only more felsic magmas?&lt;/p&gt;&#xA;" OwnerUserId="7885" LastActivityDate="2017-04-12T16:40:36.503" Title="Why is ignimbrite associated with felsic magmas?" Tags="|magmatism|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10093" PostTypeId="2" ParentId="10087" CreationDate="2017-04-11T10:10:59.563" Score="2" Body="&lt;p&gt;To be sure about why it appears to be centered around -0.2°C, you'd have to go to the original source of the graph.  However, as an educated guess, I would imagine that they are showing the anomaly compared to some recent period, such as 1961-1990 or 1971-2000, as is commonly done.  From your Wikimedia Commons link, this figure appears to be original work by a Wikipedia author.  The link does not appear to state this, so this is rather sloppy and perhaps illustrates why it's preferable to obtain information from peer reviewed sources.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the temperature increase stays at +0.4°C, it is not catastrophic.  However, considering the greenhouse gases (GHG) we have already pumped into the atmosphere, temperature increase will not stay at +0.4°C.  With currently projected increases in GHG emissions, the global average temperature increase may range from anything between +1.5°C and +6.5°C, with some regions exhibiting far larger temperature increases than that.  At such scales, the entire climate system might enter a different state, which means many regions will have climates very unlike before.  And then I'm not even mentioning the problems associated with sea level rise yet.&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2017-04-11T10:10:59.563" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10095" PostTypeId="1" CreationDate="2017-04-11T18:09:12.703" Score="1" ViewCount="903" Body="&lt;p&gt;Do winds on Earth always gets stronger when the temperature is higher or are winds only increasing when the temperature gets higher.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the difference is that when temperatures áre higher (with a constant level) that there is less difference in temperatures but in case of gétting a higher temperature the differences of temperatures are higher and that causes stronger winds?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So is a high temperature the most important factor or the increase of the temperature?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastActivityDate="2017-06-30T20:03:10.973" Title="When do winds gets stronger?" Tags="|atmosphere|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10097" PostTypeId="1" AcceptedAnswerId="10104" CreationDate="2017-04-11T20:49:14.530" Score="1" ViewCount="321" Body="&lt;p&gt;Hopefully this is on topic here - I'm wondering if there are names for the different &quot;biomes&quot; that are present within a cave. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some of these &quot;biomes&quot; include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Open (no) ceiling, sunlit, potentially with trees growing (grotto?)&lt;/li&gt;&#xA;&lt;li&gt;Dark, little to no natural light (&quot;standard&quot; cave)&lt;/li&gt;&#xA;&lt;li&gt;Containing an underground stream or lake, potentially supporting aquatic life&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I know little about caves, but they (can) have diverse areas that give rise to all sorts of interesting creatures. Are there any specific names given to the different parts of a cave?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please let me know if I can edit this question to make it clearer or more on-topic.&lt;/p&gt;&#xA;" OwnerUserId="7890" LastEditorUserId="7890" LastEditDate="2017-04-11T21:24:40.580" LastActivityDate="2017-04-12T12:54:45.433" Title="Identifying different parts of a cave" Tags="|climate|geography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10099" PostTypeId="2" ParentId="2727" CreationDate="2017-04-12T04:35:55.603" Score="0" Body="&lt;p&gt;Places with stable climates like interior deserts are likely to be least affected by climate change. They will go from being simply &quot;hellish&quot; to moderately infernal. In Middle Eastern deserts for example, summertime temperature extremes will only rise perhaps another 5-10 degrees F, but will be enough to be mostly unsurvivable. Climatological fringes like equatorial mountain ranges, and polar latitudes will suffer the most, as they are currently.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-04-12T04:35:55.603" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10100" PostTypeId="2" ParentId="10087" CreationDate="2017-04-12T04:48:30.553" Score="1" Body="&lt;p&gt;&quot;Why is the y-axis centered around -0.2 °C?&quot; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's not. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The anomaly graph is actually centered at 0 degrees and &lt;em&gt;a particular date&lt;/em&gt;, probably the late 1970s, as Gerrit alludes to. Where the axes cross is unimportant. The bottom end of this plot has been expanded to show negative anomalies (everything BELOW 0 degrees) as well as the positive anomalies (everything ABOVE 0 degrees).&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-04-12T04:48:30.553" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10101" PostTypeId="2" ParentId="10092" CreationDate="2017-04-12T04:54:12.507" Score="0" Body="&lt;p&gt;Explosive volcanism is ALWAYS associated felsic magmatism, only because of it's higher water content, whereas mafic magmas are much &quot;drier&quot;.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-04-12T04:54:12.507" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10102" PostTypeId="1" CreationDate="2017-04-12T06:48:09.297" Score="6" ViewCount="741" Body="&lt;p&gt;For example, if a hurricane has 200km/h wind speed, and it increases the translation speed from 10km/h to 30km/h, would the intensity become 220km/h?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorDisplayName="user1066" LastEditDate="2017-04-12T10:21:42.313" LastActivityDate="2017-04-13T08:26:21.817" Title="Would a hurricane increase intensity due to increasing translation speed?" Tags="|tropical-cyclone|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10103" PostTypeId="2" ParentId="10102" CreationDate="2017-04-12T10:37:27.610" Score="5" Body="&lt;p&gt;It is not the quite the numerical relationship you have described  in your question but YES the effect of translation(or forward speed) upon the intensity of tropical cyclones in the tropical oceans has been studied in this peer reviewed reference - &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2011GL050765/pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tropical cyclone translation speed and intensity correlation&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The conclusions that the authors have reached  is that there is a positive correlation with translation speed and tropical cyclone intensity. The explanation for this correlation is that a tropical cyclone with a faster translation speed reduces the exposure time of the cooling to the TC. The sea surface cooling is induced by the effect of the surface winds on the ocean and and strong winds can bring cooler subsurface water to the ocean surface . A slower moving TC is exposed to the sea surface cooling for a longer period of time and hence contributes to a negative SST feedback and has lesser chance for  reaching higher intensity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You  can read a popular science version of the peer reviewed reference in this website - &lt;a href=&quot;http://www.livescience.com/31407-hurricane-intensity-speed.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hurricane speed intensity&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2017-04-12T13:20:27.033" LastActivityDate="2017-04-12T13:20:27.033" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10104" PostTypeId="2" ParentId="10097" CreationDate="2017-04-12T12:54:45.433" Score="3" Body="&lt;p&gt;The Karstic aquifer is vertically divided in several zones. These zones host caves that are typical for them and are also named after them. The zone closest to the surface is called epikarst that is commonly riddeled with karren and also most efected by outer conditions. Below it lies vadose zone that is from hydrological aspect unsaturated and hosts mostly shafts and vertical caves. Epiphreatic zone is flooded occasionally and caves in this part are mostly horizontal, some have water some do not. The lowest is the phreatic zone that is flooded all the time. Passages of caves here are jumping up and down in vertical profile along fissures and bedding planes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is only a general explanation to find out more i would suggest this book:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://eu.wiley.com/WileyCDA/WileyTitle/productCd-0470849967.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://eu.wiley.com/WileyCDA/WileyTitle/productCd-0470849967.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6182" LastActivityDate="2017-04-12T12:54:45.433" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10107" PostTypeId="1" CreationDate="2017-04-12T14:31:51.000" Score="6" ViewCount="2937" Body="&lt;p&gt;There are 4,660 known minerals, so why are most of them so rare? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it to do with the structure of minerals?&lt;/p&gt;&#xA;" OwnerUserId="7889" LastEditorUserId="1149" LastEditDate="2017-05-02T12:21:22.517" LastActivityDate="2017-11-04T18:26:56.697" Title="Why are most minerals so rare?" Tags="|geology|rocks|mineralogy|minerals|crust|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10108" PostTypeId="2" ParentId="9650" CreationDate="2017-04-12T16:05:03.350" Score="2" Body="&lt;p&gt;I could only find this old reference(30 years old) &lt;a href=&quot;http://hurricane.atmos.colostate.edu/Includes/Documents/Publications/weatherfordgray1988-2.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Typhoon Structure As Revealed By Aircraft Reconnaissance. Part 2: Structural Variability by Weatherford And Gray 1988&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The conclusion of the authors is that the size of a tropical cyclone's eye does not have much of a observable relationship with the cyclone central pressure(MSLP) and is shown as a weak correlation. Observations reveal that the contracting eye size of a TC on the average is associated with a decreasing MSLP and an expanding eye size is associated with a increasing central pressure. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So let's look at some actual numbers from that above paper -&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are again averages for the period 1980-82 tropical cyclones that have been classified on the basis of size of the eyewall &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Eye-class                          MSLP(Central pressure in mb)  MSLP Change(in mb/12 hrs)&#xA;&#xA;No eye                             985                            +/-5&#xA;&#xA;Large eye ( &amp;gt; 28 kms)              987                            +/-8 &#xA;&#xA;Medium eye (15-28 kms)             956                            +/-9&#xA;&#xA;Small eye ( &amp;lt; 15 kms)              954                            +/-12&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Note from this table how much the MSLP fluctuates over a period of 12 hours  for the smaller eye sizes. Also remember that a vast number of cyclones do not form eyes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Word of caution if you are trying to view this table from the operational forecaster's point of view it is very likely an individual cyclone may depart from these average values. And while these data sets have been obtained for the Northwest Pacific Ocean it is likely they hold up for other basins as well. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastActivityDate="2017-04-12T16:05:03.350" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10109" PostTypeId="2" ParentId="10092" CreationDate="2017-04-12T16:33:00.863" Score="4" Body="&lt;p&gt;Felsic magmas contain much more silica (SiO2) than mafic magmas (almost by definition). The excess silica chains cause the magma to be much more viscous and therefore more prone to explosive eruptions (they trap gas and require high pressures to flow). This is why felsic magmas produce crazy explosive pyroclastic flows (forming ignimbrite) and very mafic magmas (like in Hawaii) just flow nicely downhill.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Btw, water decreases the viscosity of magmas, but the amount depends on composition as well as temperature. There is a nice transition between felsic magmas and mafic magmas showing that decrease in viscosity. Check out the source below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://link.springer.com/article/10.1007%2Fs00445-008-0217-y&quot; rel=&quot;nofollow noreferrer&quot;&gt;Whittington et al (2009): &quot;The viscosity of hydrous dacitic liquids: implications for the rheology of evolving silicic magmas&quot;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4636" LastEditorUserId="4636" LastEditDate="2017-04-12T16:40:36.503" LastActivityDate="2017-04-12T16:40:36.503" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10110" PostTypeId="1" CreationDate="2017-04-12T18:00:00.950" Score="4" ViewCount="86" Body="&lt;p&gt;I am looking for a way to separate metal oxides on the Moon. Please bear with me - it's for an ultra-hard science fiction project. Processes typical on Earth are not effective there. Heat is cheap on the Moon, there is strong constant sun that is easily concentrated. Heat also dissipates slowly thanks to the vacuum, and reflective insulation can be used to slow heat loss much more. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, I wondered if a form of controlled fractional crystallization could be used to get pure olivine from a molten melt of rock, and then the olivine could be split into forsterite and fayalite the same way. The forsterite might make decent clear glass, or if not, the fayalite can be processed with hydrogen to get iron, water, and silica, and the silica can be used to make glass. It might be necessary to apply centrifugal force to get the crystals to separate in the Moon's low gravity. If the technique works, it would seem the same process could be used to isolate other metal oxides through other paths.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hydrogen and carbon atoms are present on the level of around 100 ppm. Am I correct in thinking that mineral separation would occur this way and could be controlled to get good purity? I know there are engineering issues, but in terms of the geochemistry, is it correct that crystallization and settling would occur in this way?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Note: I heavily edited this after my continued searching on the topic finally got me to '&lt;a href=&quot;https://en.wikipedia.org/wiki/Fractional_crystallization_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;fractional crystallization&lt;/a&gt;', and then I came across a few things that made me rethink the whole thing.)&lt;/p&gt;&#xA;" OwnerUserId="4858" LastEditorUserId="4858" LastEditDate="2017-04-17T14:33:35.140" LastActivityDate="2017-04-17T14:33:35.140" Title="Is a controlled fractional crystallization process feasible on the Moon?" Tags="|mineralogy|petrology|igneous|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10111" PostTypeId="2" ParentId="10102" CreationDate="2017-04-12T19:37:28.500" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Would a hurricane increase intensity due to increasing translation speed?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As depicted below, meteorologists account for this effect in announcing the highest sustained wind speeds. The highest sustained winds account for both the motion of the storm itself and the motion of the winds relative to the moving storm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QeGSL.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QeGSL.jpg&quot; alt=&quot;Cartoon of a hurricane moving to the northwest. Winds are strongest to the northeast, weakest to the southwest.&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sub&gt;Source: &lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/D6.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.aoml.noaa.gov/hrd/tcfaq/D6.html&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The hurricane in the above diagram is moving to the northwest at 10 mph and is capable of sustaining 90 mph winds relative to the storm itself. That means that relative to land, those 90 mph winds become 100 mph winds in the northeastern portion of the storm, but only 80 mph in the southeastern portion of the storm. The highest sustained winds would be reported as 100 mph for the hurricane depicted above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That northeast section of the storm where the winds are strongest is the so-called dirty side of the storm. Note that which side is the dirty side depends on the storm's motion. The dirty side is to the east during a sharp landfall along the Gulf Coast, to the north during a sharp landfall along the US Eastern Seaboard, and to the south for eastern Pacific hurricanes making landfall on Baja California. Because tropical storms rotate clockwise in the southern hemisphere (as opposed rather to counterclockwise as depicted above), which side is the dirty side also depends on the hemisphere.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="6298" LastEditDate="2017-04-13T08:26:21.817" LastActivityDate="2017-04-13T08:26:21.817" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10112" PostTypeId="1" CreationDate="2017-04-13T02:35:39.207" Score="2" ViewCount="1667" Body="&lt;p&gt;I'm having trouble with the difference between saturated and unsaturated adiabatic lapse rates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know the unsaturated adiabatic lapse rate is approximately 5.4°F/1000ft (9.8 °C/1000 metre), in which a &quot;dry&quot; parcel of air cools at that rate. The unsaturated adiabatic lapse rate depends on what?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is the unsaturated adiabatic lapse rate lower than the saturated? From searching, I found that the unsaturated adiabatic lapse rate is lower because the air parcel releases its latent heat, which causes the air parcel to cool more slowly, but I don't seem to get it. When a &quot;dry&quot; parcel of air is cooling adiabatically, are we assuming 0% moisture?&lt;/p&gt;&#xA;" OwnerUserId="7900" LastEditorUserId="6298" LastEditDate="2017-04-18T20:54:05.433" LastActivityDate="2017-04-18T20:54:05.433" Title="Adiabatic lapse rate" Tags="|meteorology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10113" PostTypeId="2" ParentId="10112" CreationDate="2017-04-13T07:38:01.273" Score="4" Body="&lt;p&gt;Let's start with the simplest fact.  With nothing else going on, air in our atmosphere will &lt;strong&gt;always&lt;/strong&gt; be cooled at 5.4°F/1000ft (or the more widely used 9.8°C/km), due to it expanding in size (often times we'll throw a negative sign: -5.4°F/1000ft... this is just to emphasize that these lapse rates are about the air COOLING).  Every bit of the rising air cools at that rate (the oxygen, the nitrogen, even any water vapor in the air).  All of it will cool at 5.4°F/1000ft.  All rising air always expands at this same rate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However sometimes there is a second complicating factor: the rising air may cool to the point where it is holding its maximum quantity of water vapor (because when colder, air cannot hold as much water vapor).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When it reaches this point, it is saturated, and any more cooling/rising will force some of its water vapor to condense instead into liquid droplets.  For this gaseous water vapor to become a liquid, its particles must expel quite a lot of energy.  And that energy gets released into the air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So once air hits this saturation point, though its expansion continues to have a -5.4°F/1000ft impact on the temperature, it also has a second factor, that released phase change energy, warming the air some.  The result is that saturated air doesn't cool as fast.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Whenever air isn't saturated, it cools at the 5.4°F/1000ft (9.8°C/km).  We call this the &lt;strong&gt;dry adiabatic lapse rate&lt;/strong&gt; because nothing else is altering the process.  We &lt;strong&gt;aren't&lt;/strong&gt; assuming 0% moisture.  It doesn't matter, as long as it's not 100% moisture.  Water vapor cools just like every other molecule unless saturated.  The first 6 pages of &lt;a href=&quot;http://hs.umt.edu/physics/documents/BOREALIS/Lapse%20Rate%20Terms%20and%20Formulas2012.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;these notes&lt;/a&gt; go into intimate detail for why the value is 9.8°C/km, but basically it depends only on the values for gravity and the specific heat capacity of water, plus any error in the hydrostatic approximation... all of which are minuscule for large air masses in the troposphere.  &lt;strong&gt;For all intents and purposes, the dry (unsaturated) adiabatic lapse rate on Earth depends on nothing, it is always 5.4°F/1000ft (9.8°C/km)&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;Then when air is saturated, because the condensation process hinders the cooldown by adding its energy, we call it the &lt;strong&gt;moist adiabatic lapse rate&lt;/strong&gt; to distinguish it.  Picture moist as having an image of water DROPS, which you only get when saturated, due to condensation.  Moist and dry both have some water vapor.  But only moist has water droplets.  The moist adiabatic lapse rate has a &lt;strong&gt;smaller value&lt;/strong&gt; because it is cooling LESS overall (due to the warming impact from the latent heat release).  But it is still cooling, just less.  &lt;strong&gt;The moist adiabatic lapse rate varies depending on how much water is actually released&lt;/strong&gt; (which is based upon the amount of water held, or consequently, the temperature).  If you really wish to dig into the fine details, &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Moist-adiabatic_lapse_rate&quot; rel=&quot;nofollow noreferrer&quot;&gt;this AMS link&lt;/a&gt; gives the formula.  But generally the moist adiabatic lapse rate is &lt;strong&gt;around 5-7°C/km, or 2.5-4.0°F/1000ft&lt;/strong&gt;, in the low-levels of the atmosphere.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-04-13T08:08:09.723" LastActivityDate="2017-04-13T08:08:09.723" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="10114" PostTypeId="1" AcceptedAnswerId="10118" CreationDate="2017-04-13T13:37:00.110" Score="10" ViewCount="468" Body="&lt;p&gt;As far as I understand, the dominant theory of modern climate change says that recent warming is mainly caused by the massive burning of hydrocarbons that used to be stored in solid form mostly underground as petroleum, coal, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This suggests that the reverse process should contribute to a cooling of the climate (or to a slowed down warming if other processes are at play at the same time). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In particular, a cooling should have occurred throughout the period when the stocks of underground hydrocarbons were formed by the &quot;pilling&quot; of organic remains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;My questions:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Is this roughly what climate theory would predict or am I omitting some things?&lt;/li&gt;&#xA;&lt;li&gt;Was such an effect observed during the formation of the underground stocks of hydrocarbons?&lt;/li&gt;&#xA;&lt;li&gt;Can this reasoning be extended to say that a world where no solid hydrocarbons are burnt and the concentration of atmospheric hydrocarbons keeps falling (as it is captured by organism and transformed into solid hydrocarbons) would experience a continuous (if slow) cooling? Or are there some non-linearities by which the stock of solid hydrocarbons would &quot;max out&quot; or the effect of removing carbon from the atmosphere fade away?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="7904" LastEditorUserId="94" LastEditDate="2017-12-20T07:51:34.430" LastActivityDate="2020-02-21T19:38:43.510" Title="Did climate cool down when underground hydrocarbons stocks formed?" Tags="|climate-change|climate|paleoclimatology|carbon-cycle|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10115" PostTypeId="2" ParentId="10114" CreationDate="2017-04-13T15:25:59.903" Score="3" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Carboniferous&quot; rel=&quot;nofollow noreferrer&quot;&gt;carboniferous period&lt;/a&gt; was 350-270 million years ago.  The content of CO&lt;sub&gt;2&lt;/sub&gt; at that time was close to 3000 ppm, but this fell to 200-300 ppm by the end of this period.  The average temperature of earth during this period was 20-25 &lt;span class=&quot;math-container&quot;&gt;$^{\circ}$&lt;/span&gt;C this fell to an average of 12 &lt;span class=&quot;math-container&quot;&gt;$^{\circ}$&lt;/span&gt;C by the end of the carboniferous period.  So, the answer to your question is this, the carboniferous period ended because of climate change, the drop in CO&lt;sub&gt;2&lt;/sub&gt; was the main reason for this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A lot of CO&lt;sub&gt;2&lt;/sub&gt; was also used in the creation of calcium carbonate (limestone)&#xA;there was also heavy volcanic activity during this period this do lower the &#xA;temperature at least in the short time during the eruption and a few years &#xA;there after.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The last part of your question is basically can the CO&lt;sub&gt;2&lt;/sub&gt; level get too low.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The level of CO&lt;sub&gt;2&lt;/sub&gt; are regulated by plants if it falls,&#xA;several things will happen,plants will grow slower the temperature on the earth will go down making plants grow even slower.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But this is highly unlikely to happen as long as the supply of CO&lt;sub&gt;2&lt;/sub&gt; is continued.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;edit:link &lt;a href=&quot;http://www.geocraft.com/WVFossils/Carboniferous_climate.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.geocraft.com/WVFossils/Carboniferous_climate.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="2470" LastEditDate="2020-02-21T19:36:53.887" LastActivityDate="2020-02-21T19:36:53.887" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="10116" PostTypeId="2" ParentId="9919" CreationDate="2017-04-13T16:35:53.840" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;which [countries] produce how much greenhouse gases?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The United Nations Framework Convention on Climate Change (&lt;a href=&quot;https://unfccc.int&quot; rel=&quot;nofollow noreferrer&quot;&gt;UNFCCC&lt;/a&gt;), which began with the Rio Convention (1992) and was updated by the Kyoto Protocol (1997) and the Paris Agreement (2016), requires that all signatory parties (i.e., countries) submit annual reports of their GHG emissions.  See &lt;a href=&quot;https://unfccc.int/national_reports/annex_i_ghg_inventories/items/2715.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Annex I Greenhouse Gas Inventories&lt;/a&gt; for more info.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can download or plot this data using this &lt;a href=&quot;http://di.unfccc.int/GlobalmapAnnexI.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;UNFCCC tool&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Are there studies showing the relative positions carbon footprints of&#xA;  various countries?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As the other answers indicate, however, the carbon footprint is much more complicated that simply these direct GHG emissions.  It involves reassigning portions of one country's direct emissions to another country based on, say, some notion of who is ultimately responsible for the demand for that emission.  There is currently no agreed method for making that calculation.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2017-04-13T16:35:53.840" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10117" PostTypeId="2" ParentId="10077" CreationDate="2017-04-13T17:17:54.543" Score="2" Body="&lt;p&gt;It's been identified by a paleoichnologist as most probably a new species of Paleodictyon.&lt;/p&gt;&#xA;" OwnerUserId="7873" LastActivityDate="2017-04-13T17:17:54.543" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10118" PostTypeId="2" ParentId="10114" CreationDate="2017-04-13T19:39:08.510" Score="10" Body="&lt;p&gt;&lt;strong&gt;Possibly&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing you have to understand is that natural carbon sequestration via the formation of fossil fuel is VERY slow, it can take millions of years to build up the coal we burn in a day. In addition, one of the more dominant effects on the climate is solar radiance and continental position which changes over such long stretches of time, making matching such slow changes to carbon with climate change more difficult. Continent position also affects carbon sequestration and CO&lt;sub&gt;2&lt;/sub&gt; concentration directly making it even more confusing. Things like seaways and deserts can have huge effects on CO&lt;sub&gt;2&lt;/sub&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The real problem is matching coal formation to changes in CO&lt;sub&gt;2&lt;/sub&gt; concentration. &#xA;Most coal comes from the carboniferous and the Permian time periods (along with the evolution of land plants that make it), the carboniferous saw severe cooling and severe drops in CO&lt;sub&gt;2&lt;/sub&gt;. How much of this is CO&lt;sub&gt;2&lt;/sub&gt; lost to coal versus how much is just the formation of forests and other terrestrial ecosystems combined with changes in contingent positions is still up for debate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Permian however saw severe warming near its end and a rapid rise in CO&lt;sub&gt;2&lt;/sub&gt; at the same time, but most of it was relatively stable and unchanging both in CO&lt;sub&gt;2&lt;/sub&gt; and temp. It also included one of the largest volcanic events in earth's history, and again changing tectonic position. &lt;strong&gt;So although the link between CO&lt;sub&gt;2&lt;/sub&gt; and temperature is really well established we can't even say for sure such slow coal formation actually reduces atmospheric CO&lt;sub&gt;2&lt;/sub&gt; concentrations.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ssNGg.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ssNGg.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://droyer.web.wesleyan.edu/PhanCO2%28GCA%29.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Compare CO2 above to temp (red line) below. Note that just three variables together predict temprature amazing well.&lt;br&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/YDcHK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YDcHK.jpg&quot; alt=&quot;![enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.geosociety.org/gsatoday/archive/14/3/pdf/i1052-5173-14-3-4.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="2470" LastEditDate="2020-02-21T19:38:43.510" LastActivityDate="2020-02-21T19:38:43.510" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="10119" PostTypeId="1" CreationDate="2017-04-13T23:13:30.287" Score="-6" ViewCount="484" Body="&lt;p&gt;OK, you have all seen the question before BUT let's make the challenge a little different this time. I want you to use the Feynman Method ! You have to explain it simply, preferably just text but one or 2 sketch diagrams may be OK (no complicated graphs with multiple colours please) and I am going to limit you to 150 words. Who fancies the challenge - make sure you don't leave out any of the important physics.&#xA;This question is asking for an explanation of how something works. I am not interested in experimental evidence or proof, just a clear explanation that you can chat about to someone to help explain the physics behind it in as simple terms as possible. Like if your mate down the pub says, OK, tell me how this works then. &lt;/p&gt;&#xA;" OwnerUserId="7733" LastEditorUserId="7733" LastEditDate="2017-04-14T19:22:51.103" LastActivityDate="2017-04-15T00:15:01.953" Title="How does an incease in the trace gas CO2 in the atmosphere make the earth hotter?" Tags="|climate|climate-change|" AnswerCount="1" CommentCount="5" ClosedDate="2017-04-16T00:52:04.947" ContentLicense="CC BY-SA 3.0" />
  <row Id="10120" PostTypeId="1" CreationDate="2017-04-14T01:25:35.197" Score="3" ViewCount="979" Body="&lt;p&gt;Is there enough water in the oceans, ice caps, rivers and streams to cover a completely flattened earth, in proportional to land volume and water volume?&lt;/p&gt;&#xA;" OwnerUserId="7907" LastEditorUserId="6298" LastEditDate="2018-05-06T09:25:39.227" LastActivityDate="2018-05-06T09:25:39.227" Title="Is there enough water to cover the surface of a topographically normalized earth?" Tags="|ocean|water|sea-level|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="10121" PostTypeId="2" ParentId="10120" CreationDate="2017-04-14T02:19:03.633" Score="7" Body="&lt;p&gt;Here is a very simplistic approximation:&#xA;The total volume of the oceans (no lakes, rivers, water vapor) is around $1.3\ 10^9$ cubic kilometers. The surface area of Earth is around $5\ 10^8$ square kilometers. Dividing the volume by the area, we get a depth of 2.5 kilometers. The fresh water contribution is about 3% of the volume of salt water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In reality, other factors such as the fact that Earth is not spherical, density changes, and that the water will be acted upon by tidal forces and other interactions, will make the distribution uneven. &lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2017-04-14T02:19:03.633" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10122" PostTypeId="2" ParentId="10119" CreationDate="2017-04-14T21:20:35.683" Score="3" Body="&lt;p&gt;The answer can be explained very simply.   The Oxygen and Nitrogen (the non trace gases) are mostly transparent to thermal wavelength of light that leave Earth's surface.    CO2 in the air, can be compared to colored dye in water.  It's not too difficult to imagine that water with 280 ppm red dye might be visibly lighter than water with 400 ppm of the same dye.   The real answer is somewhat more complex as you need to look at different bands in the IR spectrum that get reflected by different trace gases, but that's the gist. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;55 words under.  :-)&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2017-04-15T00:15:01.953" LastActivityDate="2017-04-15T00:15:01.953" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10123" PostTypeId="1" CreationDate="2017-04-14T23:58:17.663" Score="1" ViewCount="66" Body="&lt;p&gt;An aurora is defined as a electromagnetic instance caused by polarization and ionization within a planet's higher altitudes. But what are the different phasics (beginning, middle and end) and perspectives (planetside/spaceside) of an aurora if observed from a 3 dimensional view.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question: What is an aurora called when viewed from space?&lt;/p&gt;&#xA;" OwnerDisplayName="user7384" LastActivityDate="2017-04-16T09:42:49.383" Title="What is an aurora called when viewed from space?" Tags="|auroras|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10125" PostTypeId="1" AcceptedAnswerId="13699" CreationDate="2017-04-15T23:49:23.350" Score="7" ViewCount="269" Body="&lt;p&gt;Ozone is formed in the upper atmosphere by ultraviolet light, and broken down by ultraviolet, spontaneous reactions and artificial pollutants among other things.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Suppose there were no artificial pollutants, and the sun was magically replaced with a giant heat lamp that put out no ultraviolet but kept the current temperature, how long would it take for the ozone to decay of its own accord or by reacting with natural pollutants?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The accepted answer for the other question is three days. That's wildly inconsistent with everything else I've heard said about ozone depletion taking years to recover. Maybe that's because the other question asks about ozone released near sea level, and I'm asking about ozone in the stratosphere?&lt;/p&gt;&#xA;" OwnerUserId="7911" LastEditorUserId="7911" LastEditDate="2017-10-09T19:19:21.330" LastActivityDate="2018-03-23T00:26:29.153" Title="Persistence time of ozone" Tags="|atmosphere|atmospheric-chemistry|ozone|upper-atmosphere|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10126" PostTypeId="2" ParentId="10123" CreationDate="2017-04-16T09:42:49.383" Score="2" Body="&lt;p&gt;It is still referred to as an 'aurora', examples include a relatively recent report from NASA - &lt;a href=&quot;https://www.nasa.gov/image-feature/goddard/2016/stunning-aurora-from-space&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stunning Aurora from Space&lt;/a&gt;.  Further, the aptly named document from NASA - &lt;a href=&quot;https://pwg.gsfc.nasa.gov/polar/EPO/auroral_poster/aurora_all.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Aurora&lt;/a&gt; - refers to the phenomenon by that name in reference to when it is observed from the surface or from space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whether viewed from the surface or from space, the phenomenon is still called an aurora. &lt;/p&gt;&#xA;" OwnerDisplayName="user7912" LastActivityDate="2017-04-16T09:42:49.383" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10127" PostTypeId="1" CreationDate="2017-04-16T19:44:47.187" Score="3" ViewCount="130" Body="&lt;p&gt;I grew up in a small town on a sea shore with hot and sunny summers (up to 30-35° C). I remember myself, my friends and relatives being outdoors for 12 hours a day. We never needed sunscreen, and never used it. It was considered, that skin can burn on the first day of taking a sunbath and precautions were taken, i.e. &quot;put a long-sleeved shirt on after three hours in direct sunlight&quot;. Coordinates of my hometown are &lt;a href=&quot;https://www.google.com.au/maps/place/46%C2%B045&amp;#39;35.0%22N+36%C2%B047&amp;#39;04.0%22E/@46.7597259,36.7822504,17z/data=!3m1!4b1!4m5!3m4!1s0x0:0x0!8m2!3d46.7597222!4d36.7844444&quot; rel=&quot;nofollow noreferrer&quot;&gt;46°45′35″N 36°47′04″E&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Currently, I live in another town, very close to an ocean shore, with coordinates &lt;a href=&quot;https://www.google.com.au/maps/place/41%C2%B004&amp;#39;09.0%22N+73%C2%B051&amp;#39;35.0%22W/@41.0691707,-73.8619162,17z/data=!3m1!4b1!4m5!3m4!1s0x0:0x0!8m2!3d41.0691667!4d-73.8597222&quot; rel=&quot;nofollow noreferrer&quot;&gt;41°4′9″N 73°51′35″W&lt;/a&gt;, and we have hot and sunny summers (up to 30-35° C, sometimes a little bit more). I am very surprised how aggressive sun is here. We need sunscreen all summer long, and once I had to work outdoors for 8 hours at the beginning of September, and I somehow got a sunburn. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given my childhood experience, it would be impossible for me to imagine, that I could get a sunburn at the end of summer. I simply used to get a very nice suntan over summer, and then my skin was resistant to sunburn. I wonder what is an explanation for this. One explanation could be that sun is more aggressive in my current town, than it was in my home town. But why? Another explanation, that there are some other factors involved, but I am not sure what these factors could be. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If anyone knows what is an explanation for this phenomenon, I would be most grateful for your help.&lt;/p&gt;&#xA;" OwnerUserId="7798" LastEditorUserId="7798" LastEditDate="2017-04-18T14:36:30.640" LastActivityDate="2017-04-18T14:36:30.640" Title="Difference in sun activity between two towns (Eastern and Western hemispheres)" Tags="|sun|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="10128" PostTypeId="1" CreationDate="2017-04-16T20:51:16.153" Score="2" ViewCount="472" Body="&lt;p&gt;Based on our current knowledge of CO$_2$ and current instrumental techniques, how big would a laboratory sample of air with 400ppm of CO$_2$ need to be in order to quantify the back radiation from CO$_2$? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am envisioning a large container with many cubic metres of gas, probably thermally isolated longitudinally and with a radiative IR input at one end (&lt;em&gt;A&lt;/em&gt;) plus measuring apparatus at the other end (&lt;em&gt;B&lt;/em&gt;) and some distributed thermistors throughout. We know the thermal input at &lt;em&gt;A&lt;/em&gt;, measure the thermal output at the &lt;em&gt;B&lt;/em&gt; and measure the trapped thermal energy via the thermistors. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to get a result with something like +/- 1% accuracy. Would this be possible? Assume I have a budget of at least $10,000,000.&lt;/p&gt;&#xA;" OwnerUserId="7733" LastEditorUserId="2536" LastEditDate="2017-04-17T09:15:35.103" LastActivityDate="2024-02-07T10:30:17.817" Title="How to design an experiment to quantify back radiation from atmospheric carbon dioxide?" Tags="|meteorology|atmosphere|climate|climate-change|temperature|" AnswerCount="6" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10129" PostTypeId="2" ParentId="9728" CreationDate="2017-04-16T21:36:15.423" Score="1" Body="&lt;p&gt;The answer, as already given is &quot;By radiation&quot; . But comments and other answer detail have added extra information which can be useful in understanding this in the wider context, particularly relating to arguments about the Earth's energy budget and climate change. Here is some other extra stuff to consider;&#xA;We pose the same question for the planet Venus. Venus has an atmosphere composed of nearly pure CO2 (actually about 96.5%). The surface temperature on Venus is around 750K at the equator when facing the sun and drops by a mere 5K overnight. Night and day are about 120 earth days in length so that's a pretty slow axial rotation and a very slow loss of surface heat during the planet's night. Now the atmosphere on Venus is very thick, masses of that lovely CO2, and surface pressure is about 90 times that of earth (9.2MPa). If you calculate the optical attenuation of the atmosphere to incoming solar radiation then the solar flux at the surface is a mere 4W per sq m.&#xA;It is therefore self evident with such a low solar flux at the surface that the direct radiation from the sun cannot warm the surface to 750K. It is therefore interesting to draw some energy flux diagrams (similar to the Trenberth ones for the earth) and calculate the source of all that extra heat warming the surface. Don't forget to draw 2 diagrams, one for night and one for day to check you understand how a pure CO2 atmosphere works.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a great exercise for school students (and anybody else) interested in the greenhouse effect of CO2.   &lt;/p&gt;&#xA;" OwnerUserId="7733" LastActivityDate="2017-04-16T21:36:15.423" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10130" PostTypeId="2" ParentId="9669" CreationDate="2017-04-16T22:39:19.217" Score="2" Body="&lt;p&gt;Google, &lt;strong&gt;Radiative&lt;/strong&gt; (or radiation) &lt;strong&gt;absorbtion coefficients for gases&lt;/strong&gt; (or enter a specific gas of interest). Most of this data relates to applications in combustion and refrigeration so that is the area to look at. To avoid &amp;quot;contamination&amp;quot; from all the global warming stuff try looking at older things like papers from the 1950's. I have some detailed refrigeration books from the 50's which I think had this data but are not at hand right now. Otherwise, see if you can get hold of some books like that from your library or a bookstore.&lt;/p&gt;&#xA;&lt;p&gt;Many gases were studied in great detail with proper experimental measurements to verify data well before global warming was a thing. You can find graphs of lots of useful things which can help you with an understanding of how the various gases might work in the atmosphere. For example using the emissivity of CO&lt;sub&gt;2&lt;/sub&gt; to calculate radiative heat transfer in the atmosphere with the standard Stefan-Boltzmann equation when you know the concentration of CO&lt;sub&gt;2&lt;/sub&gt; is, say, 400 ppmV. Emissivity of CO&lt;sub&gt;2&lt;/sub&gt; can be surprisingly low at atmospheric concentrations, temperatures and pressures, less than 0.002 typically.&lt;/p&gt;&#xA;" OwnerUserId="7733" LastEditorUserId="2470" LastEditDate="2021-08-08T17:14:35.193" LastActivityDate="2021-08-08T17:14:35.193" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="10132" PostTypeId="2" ParentId="9908" CreationDate="2017-04-17T03:49:35.033" Score="0" Body="&lt;p&gt;&quot;Nappe&quot; is the French word for &quot;tablecloth&quot;; think of what happens when you try to push a tablecloth any distance across a table. The resulting folded (and inverted folding) structure is very different to that created if you were to push a thick layer of dirt across the table.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The term was likely used to describe this folding over low angle thrusts as they were observed in the Alps, and then corrupted over time after being used to describe a range of low angle thrust faulted structures. &lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-04-17T03:49:35.033" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10133" PostTypeId="1" CreationDate="2017-04-17T08:53:27.663" Score="3" ViewCount="285" Body="&lt;p&gt;Thermohaline circulation (THC) is an instance in nature in which oceanic fluctuation of amassity, temperature and sodium matter is observed on a global scale. It is compared to and sometimes called the global conveyor belt due to its high propensity to transport vital environmental ecosystems across the globe. Yet, oceanographers have stated that less than 5% of the worlds' oceans has been explored. THC is also attributed to stratification of the planet's oceanic resources.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question: Why is THC pivotal to life on Earth?&lt;/p&gt;&#xA;" OwnerDisplayName="user7384" LastEditorUserId="6703" LastEditDate="2017-04-17T18:38:03.893" LastActivityDate="2017-04-17T20:17:29.350" Title="Why is Thermohaline Circulation (THC) pivotal to life on Earth?" Tags="|geochemistry|ocean-currents|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10134" PostTypeId="2" ParentId="10110" CreationDate="2017-04-17T09:13:01.303" Score="1" Body="&lt;p&gt;First, read my highly related answers to your other questions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://chemistry.stackexchange.com/q/67403/8083&quot;&gt;https://chemistry.stackexchange.com/q/67403/8083&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://chemistry.stackexchange.com/q/72483/8083&quot;&gt;https://chemistry.stackexchange.com/q/72483/8083&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The forsterite might make decent clear glass&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Probably not, see above.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;fayalite can be processed with hydrogen to get iron, water, and silica, and the silica can be used to make glass&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Again, probably not. To make the fayalite component react fully in reasonable time you are going to need to mill the olivine to very fine dust. Then, separating the silica from this fine dust in solid form is almost impossible. This will require heavy liquids (like polytungstate) which are not available on the moon. Doing this in liquid form and centrifuging will require heating, which will inevitable cause reaction of forsterite and silica to form enstatite: $\ce{SiO2 + Mg2SiO4 = 2MgSiO3}$, which is useless for glass making.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is a controlled fractional crystallization process feasible on the Moon?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Basically yes. This would be similar to a distillation process that slowly over repeated melting and solidification processes will remove Mg-rich solid from Fe-rich liquid. The problem is that even very low amounts (1% and lower) of Fe in forsterite will colour it green, which is undesirable for your glass. And that's without even considering the forsterite is not a good glass material (see links above). Seperating the Mg out will become harder and harder as you go along in your process.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Good glass material has alkalis in it. Fortunately, some lunar rocks have Na and K in them (e.g. the KREEP basalts). It has about 1 % of potassium, which could be enriched in fractional crystallisation. The problem is that you will also enrich the glass in Th, making it slightly radioactive and possibly browning with time.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-04-17T09:13:01.303" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10135" PostTypeId="2" ParentId="9975" CreationDate="2017-04-17T09:20:29.347" Score="1" Body="&lt;p&gt;Firstly you need to define what you mean by average daily temperature. What algorithm are you going to use to compute it (from several time spaced measurements), why and what do you think the result represents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously if you use a measurement which is going to be affected by very local anthropogenic activity (e.g. cars) you can expect timing of activities to affect individual measurements. a measuring station which is going to be thus affected is not really going to be useful for anything wider or general    though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When siting weather stations we try to find locations which are not subject to such local disturbances. Ideally well away from any heat producing apparatus (e.g. fixed a/c units), heated buildings, variable traffic and so on. Locations in open non urban areas are preferable for understanding changes in the weather and climate. Past locations thus chosen however have often been compromised by the expansion of nearby housing or industry as populations and cities have expanded. This is why you sometimes see references to Urban Heat Islands (UHI) in discussions of climate measurement. &lt;/p&gt;&#xA;" OwnerUserId="7733" LastActivityDate="2017-04-17T09:20:29.347" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10136" PostTypeId="2" ParentId="10114" CreationDate="2017-04-17T09:44:10.867" Score="-1" Body="&lt;p&gt;At the instant any atom of carbon is taken out of the atmosphere by a plant or animal and incorporated into its structure then that atom is &quot;off the list&quot; as it were with respect to having an effect in the atmosphere. Once in the animal/plant it may be there for eons until it becomes oil, coal,or whatever.&#xA;So it is not the ultra slow conversion of organic matter to hydrocarbons that is relevant but the amount taken up by living matter on a daily basis which is sequestered into its structure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looking at the historical record we would therefore need to think about the amount of animal and plant activity on the planet and, to some extent, its type. This is quite difficult as we only have proxy records. however as we know that CO2 is effectively plant food it seems reasonable to assume that if the proxy record shows high levels of atmospheric CO2 we might expect that fairly quickly, a few year/decade timescale, that plant life on earth would respond quickly and become very lush indeed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is of course only one factor with respect to CO2. Past volcanic activity is likely to also be relevant. &lt;/p&gt;&#xA;" OwnerUserId="7733" LastActivityDate="2017-04-17T09:44:10.867" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10137" PostTypeId="1" CreationDate="2017-04-17T11:21:17.127" Score="1" ViewCount="88" Body="&lt;p&gt;I am working with chandrayaan M3 hyper spectral data. I need to create a band depth image for identifying mineral abundances. How do i calculate the continuum reflectance value for producing a band depth image? Is that a constant value for the whole band or should i calculate the continuum reflectance for each pixel of the band. The formula given for calculating band depth is BD = 1- Reflectance at a specific wavelength/Continuum reflectance at that wavelength.&lt;/p&gt;&#xA;" OwnerUserId="2738" LastActivityDate="2017-04-17T11:21:17.127" Title="Calculating band depth image for M3 data" Tags="|remote-sensing|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10138" PostTypeId="1" AcceptedAnswerId="10151" CreationDate="2017-04-17T12:04:23.023" Score="6" ViewCount="629" Body="&lt;p&gt;More specifically, I've seen some discussion of this article:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.realclimate.org/index.php/archives/2006/09/why-greenhouse-gases-heat-the-ocean/&quot; rel=&quot;noreferrer&quot;&gt;http://www.realclimate.org/index.php/archives/2006/09/why-greenhouse-gases-heat-the-ocean/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;which claims that the observed ocean warming is explained by the ocean skin absorbing long-wavelength radiation. What I am asking is: is this mechanism necessary for ocean warming to occur? My naive understanding was that our increasing the magnitude of the greenhouse effect meant that there was less radiation escapting to space, and therefore the average temperature of the entire ocean+earth+atmosphere system will increase until it reaches a new equilibrium, where outgoing radiation again equals incoming. Is this correct? And if it is, does it not imply that the ocean must also get warmer, simply because it is a thermally coupled part of the entire warming system? I had someone tell me that the a warming atmosphere could not warm the ocean beyond an infinitesimal amount, because the atmosphere has a much lower heat capacity. But it seems to me that the constraint on the final equibilibrium temperature means that all components must warm, no matter how inefficient the means of energy transfer between them - as long as there is some means for energy transfer, increasing the overall temperature must increase each of the components. Am I right, or have I misunderstood?&lt;/p&gt;&#xA;" OwnerUserId="7920" LastActivityDate="2017-05-05T17:40:48.780" Title="Is the ocean guaranteed to warm in a warming climate, regardless of whether it absorbs LW radiation?" Tags="|ocean|thermodynamics|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10139" PostTypeId="1" CreationDate="2017-04-17T12:23:01.253" Score="8" ViewCount="3525" Body="&lt;p&gt;&lt;code&gt;gfsanl_3_20151201_0000_006&lt;/code&gt; means that the analysis was made at 0000 UTC and is valid at 0600 UTC, doesn't it? But for how long, 3 hours?&#xA;And what is the difference to &lt;code&gt;gfs_4_20151201_0000_006&lt;/code&gt;, which is listed under GFS forecast?&#xA;I cannot figure out the difference between those two.&lt;/p&gt;&#xA;" OwnerUserId="7921" LastEditorUserId="192" LastEditDate="2017-04-17T15:22:49.023" LastActivityDate="2017-04-17T20:00:42.080" Title="What is the difference between GFS analysis and GFS forecast data?" Tags="|meteorology|models|gfs|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10140" PostTypeId="2" ParentId="7424" CreationDate="2017-04-17T13:26:21.190" Score="7" Body="&lt;p&gt;Another way of looking at the question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I take 2 standard wheelbarrows of bits of plants from my garden. One wheelbarrow is used to fill the compost bin. The other goes to the bonfire.&#xA;How much ash do I have from burning compared to how much compost from the compost bin. Any gardener will know that the amount of compost will be much larger than the amount of ash. So now we need to compare the chemical composition of the ash with that of the compost. For Wood Ash there are quite a few research articles. Most of the carbon atoms in wood ash will be in the form of Calcium Carbonate (CaCO3). Percentage in the ash will vary widely but lets take a median of 50%. Ash as a percentage of original organic matter will be maybe of the order of 8% by weight. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For an original 100kg of organic matter (yes, its a big wheelbarrow) we would have 8kg of ash. In this ash would be 4kg of CaCO3. The carbon atoms would be 12% of that (relative atomic masses). So 100kg of organic bits gives you 0.48kg of carbon atoms left in the ash when you burn it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There seems to be fewer research articles on composting but we found the following approximations. For 100kg of organic matter there will be about 9% organic carbon  (9kg). Composting will turn 100kg of raw material into around 30kg of compost in which the organic carbon content will be around 25% ( 7.5kg of carbon). These figures are median &quot;pot luck selection&quot; as results can vary widely. We can however see that composting retains massively more (7.5kg) of carbon atoms compared with burning (0.48kg). The difference will be in the atmosphere.  &lt;/p&gt;&#xA;" OwnerUserId="7733" LastActivityDate="2017-04-17T13:26:21.190" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10141" PostTypeId="2" ParentId="10127" CreationDate="2017-04-17T18:30:03.287" Score="4" Body="&lt;h1&gt;I believe this is biology related, not weather related&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;I think your story is a bit anecdotal because there is no measurable evidence that the sunlight energy deposited into your skin is actually stronger in New York as compared to Ukraine. Let me offer two lines of evidence that this change is more likely to be related to you and your skin than it is to the weather.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, &lt;a href=&quot;https://en.wikipedia.org/wiki/Rostov-on-Don#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rostov-on-Don&lt;/a&gt;, (the nearest large city I could find sunlight data for) has sunnier summers than &lt;a href=&quot;https://en.wikipedia.org/wiki/New_York_City#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;New York&lt;/a&gt;. From NOAA via Wikipedia, Rostov has 286/314/293 hours of sunlight in June/July/August. New York has 257/268/268. This is largely because New York sees two more rainy days per month (and about twice as much rain on those rainy days) during the summer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sunlight intensity at a certain latitude is directly related to the angle of incidence of the sun. The declination of the sun is the relative angle from the sun to the horizon given your latitude and the time of year. The sun moves (well the Earth moves...) from the Tropic of Cancer to the Tropic of Capricorn each year, from 23.45 N to 23.45 S. During the northern hemisphere summer solstice, the sun is directly above the Tropic of Cancer. From New York, the angle of incidence of the sun is thus 41.07 N - 23.45 N =  17.62 degrees. During an equinox, when the sun is directly over the equator, the angle of incidence of the sun is 41.07 N - 0 = 41.07 degrees. The cosine of the angle of incidence is the percentage of full equatorial sunlight energy that you would receive at that latitude. Thus, in mid-summer in NY, you get cos(17.62) = 0.953 of maximum possible sunlight; at the equinox you get cos(41.07) = 0.754; at the winter solstice you get cos(64.52) = 0.430. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;For any point in the Northern Hemisphere outside of the tropics, sunlight intensity will always be greater at all times of the year at lower latitude.&lt;/strong&gt; Thus, New York always has greater sunlight intensity than Ukraine...but the difference is not very significant. At summer solstice NY gets 0.953 of the max sunlight, but Ukraine gets cos(23.3) = 0.918 of max sunlight. This is the difference between early July and mid-August in NY; not very significant. Given the close latitudes involved, you would expect to have gotten more net sun in the summer as a child than you do now due to fewer cloudy days. Since this is not what you observe, there must be some other explanation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly, I grew up near Boston, and my mom made me wear sunscreen in the summer. I used to get sunburns pretty bad. Now I'm 35 and I live in Virginia and I never wear sunscreen, even when I get to the beach. I don't remember the last time that I got a sunburn. Things change, I guess? This is a purely anecdotal observation, but then so is yours. Without any data to measure the changes (maybe I am smarter about being in shade in my older age?) all I can offer is guesses. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think you should be looking at either your skin or your behavior as the cause of this change, not necessarily at the climate. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="6703" LastEditDate="2017-04-18T12:08:15.560" LastActivityDate="2017-04-18T12:08:15.560" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10142" PostTypeId="2" ParentId="10139" CreationDate="2017-04-17T20:00:42.080" Score="10" Body="&lt;p&gt;I'm no expert at this, I've just been working with a variety of gfs gribs for a while now.  The only thing I know about them is what I've read and I'll cite them here.  I don't know where you got those files.  It looks like you're looking at the files that are sub areas, but in general the file format goes as &lt;a href=&quot;https://www.unidata.ucar.edu/data/conduit/ldm_idd/gfs_files.html&quot; rel=&quot;noreferrer&quot;&gt;shown more clearly on this website&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;data/nccf/com/gfs/prod/gfs.YYYYMMDDHH/gfs.tHHz.formidffhour !GRIB_version/ncep/model/#000/YYYYMMDDHHNNFfff/parm/level! ######&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Grid #004, 0.5x0.5 degree lat/lon grid, formid = pgrb2 (Hours F000-F180) GRIB_version=grib2 (grid number appears as #000)&#xA;Note: fhour: anl, f00, f06, f12....f384 (note: 2 or 3 digit fhour as on ftp server)&#xA;GRIB2 Note: &quot;model date&quot; and &quot;forecast hour&quot; fields are not separated by &quot;/&quot; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suggest you pull your files from &lt;a href=&quot;http://www.nco.ncep.noaa.gov/pmb/products/gfs/&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; to start with.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The anl vs fxxx is the fxxx are intermediate simulation runs that often contain uninitialized data.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Forecasts contain the same parameters as analysis AND accumulated forecast variables such as precipitation.  Analysis files, if they contain the forecast-only fields, set them to zero.  For instance, both FNL and GFS files obtained directly from NCEP, contain the CRAIN variable.  But, in the FNL file, all of the CRAIN fields will be zero.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;In summary, the FNL analysis incorporates ~10% more data than the GFS by waiting for ~3 hours longer for the data stragglers.  GFS forecasts contain accumulated fields, such as precipitation, that are missing or set to zero in the analysis fields. - &lt;a href=&quot;http://ncarrda.blogspot.com/2015/04/whats-difference-between-gfs-and-fnl.html&quot; rel=&quot;noreferrer&quot;&gt;link&lt;/a&gt; &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This analysis-forecast cycle is complex and iterative.  &lt;a href=&quot;https://rda.ucar.edu/datasets/ds083.2/docs/Analysis.pdf&quot; rel=&quot;noreferrer&quot;&gt;Here's a bit more detail&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And here is the &lt;a href=&quot;http://www.nco.ncep.noaa.gov/pmb/nwprod/prodstat/index.html#TARGET&quot; rel=&quot;noreferrer&quot;&gt;current status in real time of models running&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="7865" LastActivityDate="2017-04-17T20:00:42.080" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10143" PostTypeId="2" ParentId="10133" CreationDate="2017-04-17T20:17:29.350" Score="2" Body="&lt;p&gt;My answer is a bit off topic to your actual question, but addresses something you said:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;oceanographers have stated that less than 5% of the worlds' oceans has been explored&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I would venture that less than 5% of the &lt;strong&gt;ocean floor&lt;/strong&gt; or &lt;strong&gt;deeper ocean depths&lt;/strong&gt; is perhaps where less than 5% has been explored.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We've really been over the vast majority of the ocean surface at some point (and have tools like satellites that give us significant data on the rest).  Here's the current location of floating buoys:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wsSwQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wsSwQ.jpg&quot; alt=&quot;buoys&quot;&gt;&lt;/a&gt;&#xA;(&lt;a href=&quot;http://www.argo.ucsd.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Argo Website&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It looks pretty comprehensive near the surface!  Still, there's often hundreds of miles between sites, so while it means we have\do cover a fair bit of the area (more than 5%!), we aren't everywhere at once.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And it's important to note that a a significant part of thermohaline circulations are near the surface, generally the red areas on this map:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[&lt;img src=&quot;https://i.stack.imgur.com/NoIf0.png&quot; alt=&quot;thermohaline&quot;&gt;&lt;br&gt;&#xA;(&lt;a href=&quot;https://en.wikipedia.org/wiki/Thermohaline_circulation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the big thing to take home is that even where we don't have as much data, we can see the large thermohaline circulations well because of its scale and relative continuity.  It's quite comparable to the upper atmosphere, where we also don't get data on large parts of the upper atmosphere, but can rather well diagnose jet stream fluctuations.  Here's the upper air sounding network:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7gUCg.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7gUCg.jpg&quot; alt=&quot;soundingsites&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;(&lt;a href=&quot;https://learn.weatherstem.com/modules/learn/lessons/120/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weatherstem.com upper air observations lesson&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both networks are aided some by satellite and ship/plane observations, but overall, despite fairly limited observations, the circulations are quite evident because of their size and impacts.  So we have a pretty good handle on what's going on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hopefully someone else is able to better address your central question about why it is vital to life on Earth!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2017-04-17T20:17:29.350" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10145" PostTypeId="1" AcceptedAnswerId="10152" CreationDate="2017-04-18T12:18:40.490" Score="9" ViewCount="789" Body="&lt;p&gt;I'd like to have a rough idea of how large local surface CO2 concentration vary due to natural processes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;For example, a purely hypothetical experiment:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I set up some CO2 monitors in a wide variety of locations around the globe (e.g. mid-ocean, jungle, desert, plains, tundra, mountaintop, beach...), say at 2 meters off the ground, and took some measures to avoid close proximity to substantial anthropogenic CO2 sources (industrial, transportation, population, farms) and fires or episodic geological sources (e.g. &lt;a href=&quot;https://earthscience.stackexchange.com/questions/10145/#comment19754_10145&quot;&gt;volcanos or magma pockets under lakes&lt;/a&gt; per @jamesqf), roughly speaking what might the variation look like? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A starting guess might be that they'd all be nearly featureless, around 400ppm, with only say +/- 10 or 20 ppm daily and yearly oscillations. Of course there is a whole lot of important science within those variations, but for the purposes of this question, I'd call those variations small.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would my detector in a forest or jungle see higher peaks, or deeper troughs than one in a desert, or mid-ocean? What might the biggest excursions be? Might it ever reach down to 300 or up to 500 ppm &lt;em&gt;due to natural processes&lt;/em&gt;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason I'm asking is that while I tried to so some searches, it is very popular to show data from urban and suburban locations, where peaks of 500 or 600 ppm or even higher are seen that are attributed to wind direction and concentrated man-made sources, and that variation is not what I'm after. Here is just one example (&lt;a href=&quot;https://weather.usu.edu/htm/file39359/24-hour-co2-concentration&quot; rel=&quot;noreferrer&quot;&gt;48 hours&lt;/a&gt; and &lt;a href=&quot;http://weather.usu.edu/htm/co2-concentration&quot; rel=&quot;noreferrer&quot;&gt;yearly&lt;/a&gt;) but there are many much larger studies published with sensors in urban areas.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2017-04-18T19:59:32.963" LastActivityDate="2017-04-19T20:10:12.337" Title="How large can local surface CO2 concentration vary due to natural processes?" Tags="|atmosphere|co2|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10148" PostTypeId="1" CreationDate="2017-04-18T19:28:54.937" Score="5" ViewCount="131" Body="&lt;p&gt;The Seeker.com article &lt;a href=&quot;https://www.seeker.com/earths-inner-core-has-its-own-inner-core-1769514804.html&quot; rel=&quot;noreferrer&quot;&gt;Earth's Inner Core Has Its Own Inner Core&lt;/a&gt; states that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;researchers at University of Illinois and Nanjing University in China have made a bizarre discovery. They've found that the Earth's inner core has an inner core of its own, like a Russian nesting doll, that has different properties from what scientists have previously imagined&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Is it possible that there could be three cores?&lt;/p&gt;&#xA;" OwnerUserId="7933" LastEditorUserId="595" LastEditDate="2017-04-18T19:37:52.777" LastActivityDate="2017-04-24T00:48:20.977" Title="Earth's inner core has an inner core inside itself. Are there three inner cores?" Tags="|geology|seismology|core|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10149" PostTypeId="1" AcceptedAnswerId="10150" CreationDate="2017-04-18T21:15:23.730" Score="10" ViewCount="15064" Body="&lt;p&gt;In researching glacial features, I came across the terms esker, drumlin, and kame. I know that they are all depositional features that are shaped like a mound. My impression is that an esker is longer than a drumlin, which is longer than a kame. What other differences distinguish between the three?&lt;/p&gt;&#xA;" OwnerUserId="7934" LastEditorUserId="94" LastEditDate="2018-02-04T07:59:17.943" LastActivityDate="2021-06-14T11:47:16.597" Title="Esker vs. Kame vs. Drumlin - what's the difference?" Tags="|geomorphology|terminology|glaciology|glaciation|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10150" PostTypeId="2" ParentId="10149" CreationDate="2017-04-18T21:38:42.737" Score="10" Body="&lt;p&gt;&lt;em&gt;Eskers&lt;/em&gt; are glaciofluvial deposits from sediment carrying subglacial tunnels. As the water emerges from a tunnel at the bed of an ice sheet or glacier it will slow down. Since the sediment movement depends on water velocity the sediment will be deposited. The results is a highly localised deposition. When glaciers retreat the point of emergence for the water will of course change with the edge of the glacier. Hence the deposition will occur progressively further upstream leaving a narrow trail of sediment accumulation. Much more can be said but the result is ridges sometimes hundreds of kilometres long that extend pretty much perpendicular to the past glacier edge, the way the water flows from within to the edge of the glacier. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Kames&lt;/em&gt; are hummocky terrain formed by material that has been transported by glacier melt water. The reasons for the hummocks is that when the sediment was deposited, chunks of ice were buried by the sediments and when that ice melted a hummocky terrain was formed. A key here is that the deposition of sediments from sediment transport would not be able to form the irregular hummocky terrain as a primary feature, there has to be other processes involved. Kames are therefore usually an extensive land form that does not necessarily have a preferred extension. As with eskers the origin of the water and sediment is the same, the base of the glacier.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, &lt;em&gt;drumlins&lt;/em&gt;. These forms are elongated land forms, in the direction of ice flow, often some kilometres in length, width of a few hundred metres and a height of tens of metres. This varies a lot though. These forms are not formed by running water and sediment transport but formed beneath the ice. In the literature they have been described as both depositional and erosional land forms, although a depositional formation seems to be most common. They seem to consist of whatever material is present beneath the ice but because the most common sediment beneath glaciers is till this is also what most drumlins consist of.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So eskers and kames have som relationship in the origin of the sediment that make them up. Drumlins are of completely different processes. Much more could be said and all details are not completely understood when it comes to many glacial landforms and their formation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;ADDED:&#xA;The formation of drumlins, and hence also their characteristics is too complex to be explained in a short answer here. Three scientific papers that will help gaining a deeper understanding of drumlin formation are (I suggest googling on the titles to find copies): &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Patterson, C.J., Hooke, R.L., 1995. Physical environment of drumlin formation. Journal of Glaciology 41 (137), 30–38.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Stokes, C.R., Spagnolo, M., Clark, C.D., 2011. The composition and internal structure of drumlins: complexity, commonality, and implications for a unifying theory of their formation. Earth-Science Reviews 107, 398–422.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Roger LeB. Hooke, Aaron Medford, 2013. Are drumlins a product of a thermo-mechanical instability? Quaternary Research. &lt;a href=&quot;http://dx.doi.org/10.1016/j.yqres.2012.12.002&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://dx.doi.org/10.1016/j.yqres.2012.12.002&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="81" LastEditDate="2020-04-14T17:37:21.257" LastActivityDate="2020-04-14T17:37:21.257" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="10151" PostTypeId="2" ParentId="10138" CreationDate="2017-04-18T22:17:47.627" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;My naive understanding was that our increasing the magnitude of the&#xA;  greenhouse effect meant that there was less radiation escapting to&#xA;  space&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That's 100% correct.   If we assume constant solar input, there's only two ways the Earth's surface temperature can change.   Albedo and Thermal radiation.   Greenhouse gas driven climate change means exactly what you said - less heat radiates off Earth into space.    Most of this heat goes into the Ocean.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;And if it is, does it not imply that the ocean must also get warmer,&#xA;  simply because it is a thermally coupled part of the entire warming&#xA;  system? I had someone tell me that the a warming atmosphere could not&#xA;  warm the ocean beyond an infinitesimal amount, because the atmosphere&#xA;  has a much lower heat capacity.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Your friend is half right, and half wrong.   Air has a bit over 1/4th the heat capacity compared to water and it's about 800 times less dense, so he's correct, but it's not that simple.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sunlight - somewhat counter-intuitively, isn't great at warming oceans because the photons from sunlight are energetic enough to evaporate water molecules into gas molecules.  Oceans have low albedo which means they absorb most of the energy from the sunlight, but much of that heat is lost in evaporation by visible light photons.   While that has nothing to do with your question, it's worth pointing out that sunlight isn't as good at warming oceans as one might think.   (If anyone has one of those solar mirror ovens, I'd be curious to see how well they work on pure water . . . just out of curiosity, evaporation loss vs rate of warming).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The back-radiation from the atmosphere is comparatively much less total solar energy, but oceans are good at absorbing and storing thermal back-radiation reflected back off the greenhouse gas rich atmosphere into the ocean.   This is a tiny amount of the total heat Earth gets from sunlight, and the increase of this radiation due to greenhouse gas is a fraction of one percent of solar energy, but it adds up.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One way to explain this is that 85 degree air will warm 80 degree water. That's a thermodynamic law.  It just takes a while and because the heat capacity and density of water is much greater, it takes about 4 liters of air to give 1 degree back to warm 1 cc of water 1 degree.  But despite the inefficiency, warmer air still transfers heat into colder water.  It takes many decades, perhaps centuries, for the oceans to catch up to the warming air, but air, however inefficiently, does warm the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The quirk in this, is that the oceans, despite warming much more slowly than the air, are still &lt;a href=&quot;http://www.oceanscientists.org/index.php/topics/ocean-warming&quot; rel=&quot;nofollow noreferrer&quot;&gt;absorbing over 90%&lt;/a&gt; of the trapped heat added by the increase in greenhouse gas.   It's a matter of scale.  Oceans warm slowly because they're enormous and always circulating and it takes much more energy to war them, but they also absorb most of the heat, for the same reason, they're very good at holding heat.  Slow to heat up, but also, slow to cool down.  That's why bodies of water often feel warm when you go swimming at night.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I should probably add something about increased evaporation in higher air temperature, which effectively cools the oceans and surface air, but also increases the greenhouse effect with an increase in water vapor, but running those numbers is a bit over my pay-grade.   The greater efect is the one mentioned above.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2017-04-19T18:25:19.987" LastActivityDate="2017-04-19T18:25:19.987" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="10152" PostTypeId="2" ParentId="10145" CreationDate="2017-04-19T04:10:43.333" Score="4" Body="&lt;p&gt;There are many studies quantifying temporal CO2 variability for a static location. Conducting such studies isn't particularly difficult, the cost of equipment is low, and it's an easy way to publish meaningful results. You may have a hard time wading through all of the publications to select the few that mean anything to you, specifically.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A quick 2 minute search found this paper (among a slew of others), entitled, &lt;a href=&quot;http://home.olemiss.edu/~suman/Suman2002indianforester.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Diurnal and Seasonal Variation of CO2 levels of surface air in Garwhal Himalaya&lt;/a&gt;&#xA;in which this graph highlights daily CO2 variations over the course of a year, in mmol/mol. You'll have to look up the conversion to ppm CO2:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ME17X.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ME17X.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You may to search using these key words: &lt;a href=&quot;https://www.google.com/search?q=CO2%20variation%20as%20a%20function%20of%20vegetation#q=CO2%20variability,%20diurnal,%20yearly&quot; rel=&quot;nofollow noreferrer&quot;&gt;CO2 variability, diurnal, yearly&lt;/a&gt;&#xA;&lt;a href=&quot;http://www.hydrol-earth-syst-sci.net/13/987/2009/hess-13-987-2009.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seasonal and diurnal variations in moisture, heat and CO2 fluxes over a typical steppe prairie in Inner Mongolia, China&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1034/j.1600-0889.2003.00061.x/pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Temporal variations of atmospheric CO2 concentration in a temperate deciduous forest in central Japan&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://meteo.lcd.lu/papers/co2_patterns/co2_patterns.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seasonal and Diurnal CO2 Patterns at Diekirch, LU&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://faculty.geog.utoronto.ca/Chen/Chen%27s%20homepage/PDFfiles/p96_2004JD005546.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Interannual variability in the atmospheric CO2 rectification over aboreal forest region&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7333" LastEditorUserId="7333" LastEditDate="2017-04-19T04:18:12.723" LastActivityDate="2017-04-19T04:18:12.723" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10153" PostTypeId="2" ParentId="10138" CreationDate="2017-04-19T04:44:14.823" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;That's in a nutshell, simple conduction air to water.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No....it's not so simple.....far from it. In fact, there are several rather complicated processes occurring simultaneously, none of which involve the simple transfer of heat from warm air to cool sea water, as stated by userLTK, above. From Skeptical Science:&lt;br&gt;&#xA;&lt;a href=&quot;https://www.skepticalscience.com/How-Increasing-Carbon-Dioxide-Heats-The-Ocean.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;How Increasing Carbon Dioxide Heats The Ocean&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Sunlight penetrating the surface of the oceans is responsible for warming of the surface layers. Once heated, the ocean surface becomes warmer than the atmosphere above, and because of this heat flows from the warm ocean to the cool atmosphere above.&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But really, you should read the entire text for a good explanation of the process that leads to warming seas. Another important resource is found at the Scripps Institution of Oceanography: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://scrippsscholars.ucsd.edu/vramanathan/content/physics-greenhouse-effect-and-convection-warm-oceans&quot; rel=&quot;nofollow noreferrer&quot;&gt;Physics of greenhouse effect and convection in warm oceans&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;On average, convective regions are more humid, trap significantly more longwave radiation, and emit more radiation to the sea surface. The greenhouse effect in regions of convection operates as per classical ideas, that is, as the SST increases, the atmosphere traps the excess longwave energy emitted by the surface and reradiates it locally back to the ocean surface. The important departure from the classical picture is that the net (up minus down) fluxes at the surface and at the top-of-the atmosphere decrease with an increase in SST; that is, the surface and the surface-troposphere column lose the ability to radiate the excess energy to space.&lt;/em&gt;&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;The cause of this super greenhouse effect at the surface is the rapid increase in the lower-troposphere humidity with SST; that of the column is due to a combination of increase in humidity in the entire column and increase in the lapse rate within the lower troposphere. The increase in the vertical distribution of humidity far exceeds that which can be attributed to the temperature dependence of saturation vapor pressure; that is, the tropospheric relative humidity is larger in convective regions.&lt;/em&gt;&lt;/strong&gt; &lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-04-19T04:44:14.823" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10154" PostTypeId="1" AcceptedAnswerId="12892" CreationDate="2017-04-19T11:00:23.370" Score="10" ViewCount="198" Body="&lt;p&gt;As radar beams travel away from radars, they &lt;a href=&quot;http://tornado.sfsu.edu/geosciences/classes/m415_715/monteverdi/radar/Wikipedia/Weather_radar.html#Determining_height&quot; rel=&quot;nofollow noreferrer&quot;&gt;increase in elevation&lt;/a&gt; and &lt;a href=&quot;http://www.radartutorial.eu/01.basics/Angular%20Resolution.en.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;widen&lt;/a&gt;.  Have any studies attempted to quantify the rate at which warning skill (such as in &lt;a href=&quot;http://www.nws.noaa.gov/oh/rfcdev/docs/Glossary_Verification_Metrics.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;FAR and POD&lt;/a&gt;) deteriorates as a function of radar distance?  It would seem quite useful in objectively diagnosing where new radar sites may be most vital (and where to put them in countries that do not yet have radars), and could be useful in guiding warning decisions as well.  I'm particularly interested in tornado warnings in the US, though any related data/studies would be very interesting.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-12-13T15:01:50.033" LastActivityDate="2017-12-13T23:11:10.810" Title="Do warnings verify better nearer radars?" Tags="|meteorology|statistics|tornado|research|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10155" PostTypeId="2" ParentId="10145" CreationDate="2017-04-19T20:10:12.337" Score="3" Body="&lt;p&gt;This is a good question because it prompts one to think about the many and varied natural sources of CO2 in the atmosphere. Of course your measuring apparatus will only show NET CO2, i.e. Sources-Sinks. So you need to think about CO2 sinks too.&#xA;Start by making a list of all the possible sources and sinks. Then consider which apply in any given location for the apparatus. &#xA;I would suggest that one of the main sources would be plant life so you will find quite a difference between an instrument in a tropical rainforest compared to a dry desert.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ocean measurements will be interesting as oceans contain dissolved CO2 and it tends to come out as the temperature goes up. In reality a bit more complicated owing to exact surface exchange mechanisms, partial pressure of CO2 in the atmosphere , etc.&#xA;You starting guess of +/- 10-20ppm looks low compared to my own guess. I would have said +/- 50-100 but it would indeed have been a guess like yours.&lt;/p&gt;&#xA;" OwnerUserId="7733" LastActivityDate="2017-04-19T20:10:12.337" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10156" PostTypeId="2" ParentId="10074" CreationDate="2017-04-20T01:38:51.183" Score="1" Body="&lt;p&gt;Strike and dip are one way of describing the orientation of a plane in 3 dimensions. The strike is the angle of the intersection of the plane with a horizontal surface so the strike of a horizontal plane is undefined. Just as two intersecting lines define a point, two intersecting planes define a line. You can define a line perpendicular to the line of strike and this defines the direction of dip. If you imagine a vertical plane that intersects the horizontal surface along that line it will intersect your original geologic surface along another line. The angle between the direction of dip and the geologic surface is the dip angle, or just called the dip. Conventionally, the dip is always measured so it is the angle down from the horizontal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If someone gives you a strike and dip, you still need one more piece of information to determine the orientation of the plane. That's because you need to know if the plane is dipping to your left or the right if you are looking in the direction of the strike. Some conventions specify the general direction of dip (e.g. to the east) but I prefer to use a convention where you define the strike direction so that your dip is to the right side (the right-hand rule) So if the strike is a line that points, for example 10 degrees (east of north) and 190 degrees (10 degrees west of south) and the dip is 30 degrees to the west you would say strike 190 degrees, dip 30 degrees. The dip is the maximum angle that can be measured between your geologic plane and the horizontal. Sometimes it is hard to tell if your are measuring the angle exactly down-dip and the value of that apparent dip will be less than the true dip.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another way to describe the orientation of the same geologic plane is use the bearing and plunge (also termed plunge and azimuth). Go back to the vertical plane perpendicular to strike and its intersection with the geologic plane. Imagine looking along the line where that plane intersects the horizontal and facing down dip. That direction is the bearing (the strike plus 90 degrees if you are using the right-hand rule). The plunge is just the dip angle. The reason it is called something different is that you can use the same terminology to describe any linear feature such as the line where a bed intersects a fault.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suspect that when you say, &quot;dip shows the orientation of the geological plane&quot; you mean both the dip angle (the plunge) &lt;em&gt;and&lt;/em&gt; the bearing of the dip line. So in actuality you are still using two values with the bearing being 90 degrees from the strike. The reason you can't just use the strike is that that does not give you the angle value.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is another way to define the orientation of a plane by defining the vector that is normal to the plane. That line forms an angle of 90 degrees with the line of dip. The convention in structural geology is to use the vector where the perpendicular to the plane points downward, not up in the air. The bearing and plunge of that vector is used to plot features on stereo-nets - a handy way to reduce the orientation of a number of planes to a number of points.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-04-20T01:38:51.183" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10157" PostTypeId="1" AcceptedAnswerId="10367" CreationDate="2017-04-20T06:31:53.187" Score="10" ViewCount="12951" Body="&lt;p&gt;For a uniform mixture of ideal gases, I think that the concentration of a gas reported in parts per million by volume (ppmV) and micro-moles per mole (μmol/mol) would be the same.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I see atmospheric CO2 discussed, I have seen both units used, depending on the source. See for example, the comments under &lt;a href=&quot;https://earthscience.stackexchange.com/a/10152/6031&quot;&gt;this answer&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since multi-atomic gases like N2, O2, H2O and CO2 are not ideal gases (even monatomic gases are not absolutely ideal) I would guess that for realistic atmospheric samples at different altitudes and times, the CO2 concentrations expressed in ppmV and μmol/mol would not be numerically identical. Further, due to the variations in concentrations of the other constituents they wouldn't even be strictly proportional.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a handy, approximate conversion constant, or function, that is more accurate than unity? Is there a  nearly-exact one?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2017-05-09T19:00:55.520" LastActivityDate="2020-08-06T19:55:19.003" Title="ppmV versus μmol/mol for atmospheric CO2 - how to convert?" Tags="|atmosphere|atmospheric-chemistry|upper-atmosphere|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10158" PostTypeId="1" CreationDate="2017-04-20T06:47:50.020" Score="0" ViewCount="617" Body="&lt;p&gt;The theory of a GHE in a planetary atmosphere is rather well known. Many claim it is no longer a theory but actually proven as a fact.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However I have been reading a lot of things Richard Feynman said about science and have decided to apply some of them to the GHE. I am going to start from an assumption this is something new I have just come across and after listening to the explanations ask: &quot;How do we know it is like that, what can we measure or test to confirm it?&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now Richard Feynman had a very useful piece of lab equipment which he used quite a lot. I've got one of them too, albeit a version with a lower spec and with a rusty outer casing that shows its age. However I have tested it recently and it is up to spec and passes its boot up self-test. You might have a higher spec one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So please apply your brain to this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Planetary Atmosphere Thought Experiment.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You have 2 identical planets, same mass, same rotational speed, same orbit around a sun. They have gaseous atmospheres of identical heat capacity and of the same height. The orbits are perfectly circular and regular. The planets have reached a thermal equilibrium. The ONLY difference between the 2 planets is that one has greenhouse gases in its atmosphere and the other does not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What differences would the GHE make to the conditions on the 2 planets?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Well fairly obviously if there is a GHE on one its surface temperature will be higher. We will call the planet with the GHE planet G, and the one without planet N.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;G will have a higher surface temperature. Now suppose we are looking from outside, from space, at G and N. Will they look different to any measuring apparatus? We know the solar input to each is the same (orbits are the same) so, as we know G and N are in thermal equilibrium it MUST be the case that quantity of radiation leaving the planets is the same. So if we measure it like we do for any celestial body we will measure the same &quot;effective temperature&quot; looking at G and N.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;G and N will have the same effective temperature. The surface of planet G will be hotter than N. The height of the atmospheres is the same so the temperature gradient in the atmosphere will be higher on G. Its lapse rate is higher. For any given height in the atmosphere the temperature of the atmosphere on G is higher at that height, than the temperature on N.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So G has a higher surface temperature and the temperature of its atmosphere is higher. Yet, as both planets are radiating into space at the same rate their measured effective temperatures are identical.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This then leads to my main question;&#xA;What physical parameter can we measure if given ONE planet, without any knowledge of what the conditions are on the other, in order to determine whether we have been given planet G or N?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT 22/4/17.&#xA;I am adding this edit as the answers attempted so far have all really been an explanation of the details of how the GHE works on Earth and the specifics of CO2. I would like the question properly addressed as it is in connection with the thought experiment proposed. The answer I am looking for will likely be given in general terms, applicable to the GHE from any greenhouse gas or a combination of 2 or more and also be one generally applicable to any planet you might find anywhere. Multiple parameters may be measured. You do have access to the planet's surface or any chosen point in the atmosphere. To clarify the gaseous atmospher may be any combination of gases or a single gas, the specific heat capacity of the atmosphere is the same on each planet, the height of the atmospheres is defined as the height of the troposphere so the tropospheres are the same height. Layers of atmosphere above the troposphere can vary between the 2 planets as I believe there is no claim or evidence that the presence or absence of a greenhouse gas in these upper layers is significant (if you have knowledge otherwise please state it).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT 26/4/17 . This edit follows the question being put &quot;on hold&quot; as being too broad. The actual question posed is quite specific and narrow and is also  brief and to the point. It is the &quot;What physical parameter(s) can we measure ?&quot; type of question. That is not broad at all, it is specific and it follows the format of what Richard Feynman suggests.&#xA;The answer is expected to be in the form of &quot;We would measure X&quot; or &quot;We would measure X and Y&quot; or &quot;We would measure X, Y and Z&quot;. Obviously the answer could be expanded via something like &quot;We would measure X and if it is below n then that shows...&quot;.&#xA;So based on a simple and specific questions, and the expected simple answers, the claim of those who put this on hold for being too broad looks erroneous and I suggest they revise their view as it does not accord with a logical examination of the situation as I have explained.   &lt;/p&gt;&#xA;" OwnerUserId="7733" LastEditorUserId="7733" LastEditDate="2017-04-26T22:55:58.873" LastActivityDate="2017-04-26T22:55:58.873" Title="Which physical parameters can we actually measure to confirm the existence of the Greenhouse Effect (GHE)?" Tags="|atmosphere|climate|climate-change|planetary-science|" AnswerCount="3" CommentCount="10" ClosedDate="2017-04-22T02:59:32.987" ContentLicense="CC BY-SA 3.0" />
  <row Id="10160" PostTypeId="1" AcceptedAnswerId="10177" CreationDate="2017-04-20T08:27:47.757" Score="15" ViewCount="19501" Body="&lt;p&gt;I have seen several lists with &lt;a href=&quot;http://www.greeneatz.com/foods-carbon-footprint.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;CO&lt;sub&gt;2&lt;/sub&gt; emissions by weight&lt;/a&gt; for producing several different food products. I think this is an interesting consideration, and possible argument for vegetarianism/veganism.&lt;/p&gt;&#xA;&lt;p&gt;I would however prefer a list with CO&lt;sub&gt;2&lt;/sub&gt; emissions by calorie, as I feel it is a more useful at estimating consumption. Further more the above lists unfairly disadvantage calorie dense foods, or foods with low water content. I haven't been able to find a detailed list (e.g. &lt;a href=&quot;http://www.co2list.org/files/carbon.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; is to coarse for my purposes, but otherwise good), so &lt;strong&gt;does anyone know of such a list&lt;/strong&gt;?&lt;/p&gt;&#xA;&lt;p&gt;Preferably the list should be location neutral (i.e. if transportation CO&lt;sub&gt;2&lt;/sub&gt; cost is taken into account it should be general enough to apply for all areas)&lt;/p&gt;&#xA;" OwnerUserId="7941" LastEditorUserId="2470" LastEditDate="2022-05-20T17:44:25.603" LastActivityDate="2022-05-20T17:46:01.457" Title="CO2 emissions per calorie (food)" Tags="|climate-change|co2|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="10165" PostTypeId="2" ParentId="10158" CreationDate="2017-04-20T17:40:34.147" Score="5" Body="&lt;h1&gt;Reality is not as simple as your thought experiment&lt;/h1&gt;&#xA;&lt;p&gt;The problem with your thought experiment is that, even though you are holding sunlight intensity identical between your two planets, there are too many factors that actually affect the planet's temperature for any one measurement to give you conclusive proof of the greenhouse effect. There are two primary factors affecting the planet's temperature, given constant sunlight energy:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Greenhouse gasses&lt;/strong&gt;: Water vapor, CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;, and methane are all significant greenhouse gasses, as are others. Greenhouse gasses act by absorbing the IR radiation emitted from the surface of the Earth, thereby preventing it from being emitted into space. This 'traps' more heat in the system and warms up the planet.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Albedo&lt;/strong&gt;: The amount of sunlight reflected from the planet affects the total energy received from the sun. Things that are light colored, like ice and clouds will reflect more light, while things that are darker colored like dense forest will absorb more.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;So those two factors are easy enough. Where this gets complicated is from all the second order effects between those two factors. These are called feedback loops, and all the feedback loops feed back into each other. Examples:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;As temperatures rise, more water vapor enters the atmosphere, which increases the greenhouse effect (marginally), and increases the temperature. However, the increase in water vapor causes more clouds to form, which increases albedo and decreases temperatures.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;If rising temperatures/precipitation/CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; levels cause plant density to increase, then albedo (usually) decreases, and temperatures increase. However, plants also remove CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; from the atmosphere and deposit it in the soil, which decreases the greenhouse effect and lowers temperatures.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;If rising temperatures cause more ice to melt, then ice cover goes down and albedo goes down causing temperatures to rise. However, areas above ice sheets generally have very little moisture in the air; if the ice sheets melt there may be more cloud formation, partially offsetting the loss of albedo.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;That is only a couple feedback mechanisms I could think of off the top of my head. There are many, many others. It is these feedback mechanisms that make the science of climate change harder to predict.&lt;/p&gt;&#xA;&lt;p&gt;Therefore, we cannot point to one single parameter that will cause use to identify the greenhouse effect, which is why it has taken so long to get to a scientific consensus about if an how the greenhouse effects work. Any one parameter could have dozens of feedback processes affecting how it affects global temperature, and its is only through decades of careful study that we have been able to demonstrate with high confidence the link between increasing CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; levels and increasing temperature.&lt;/p&gt;&#xA;&lt;h1&gt;To understand more fully, you have to read the IPCC report&lt;/h1&gt;&#xA;&lt;p&gt;Here is the &lt;a href=&quot;http://ar5-syr.ipcc.ch/ipcc/ipcc/resources/pdf/IPCC_SynthesisReport.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC's Fifth assessment&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;This is the holy grail of current theory that is widely accepted in the scientific community regarding anthropogenic global warming. The IPCC reports are careful to make only claims supported by evidence which is why the contents of these reports are supported by 95%+ of the scientific community. This report neatly summarizes the important factors and measurable evidence (which is what you are after).&lt;/p&gt;&#xA;&lt;p&gt;Once you read about the measurable evidence, you will have to go to the scientific literature to get the full picture of how the evidence was collected, and its justification in supporting the IPCC's report. To be honest, the whole picture is more than any one person can manage. No one will have equal knowledge of the temperature measurement methodology, fluid mechanics of the circulation models, science of cloud related feedback, etc. It is a collaboration of researchers in all these fields and more that allows the synthesis that is the IPCC report to exist.&lt;/p&gt;&#xA;&lt;h1&gt;Conclusion&lt;/h1&gt;&#xA;&lt;p&gt;Having contributed (a decade ago) to some of the oceanic circulation models, I feel connected to a small piece of the puzzle. I am a computer scientist, not an oceanographer, chemist, geologist, physicist or any of the other specialties needed to build the full picture. I have my own criticisms of how some of the computer models implement the Navier-Stokes equations (possibly since corrected), but I can satisfy myself that there are many models that generally agree and that the results in my little part of the puzzle are generally correct. I am sure that many specialists in other fields feel the same way.&lt;/p&gt;&#xA;&lt;p&gt;If you want to get a similar confidence about why models showing future warming are correct, you should embark on some study of your own. Pick a field that interests you and is commensurate with your math skills and investigate.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;h1&gt;Edit for further explanation:&lt;/h1&gt;&#xA;&lt;p&gt;The greenhouse effect itself varies with more than just Carbon Dioxide level. Lets use the cases of Venus, Earth, and Mars to compare.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Venus&lt;/strong&gt;: Surface temperature is about 735 K. By &lt;a href=&quot;https://en.wikipedia.org/wiki/Wien%27s_displacement_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wien's law&lt;/a&gt;, the maximum wavelength for IR radiation from the surface (into space) is 2.897 mm / 735 K = ~4000 &lt;span class=&quot;math-container&quot;&gt;$\mu\text{m}$&lt;/span&gt; or 2500 cm&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt; as it is more commonly stated. Take a look at this chart of Carbon Dioxide's absorption spectrum:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yQLHL.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yQLHL.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Venus has a surface emission peak that lines up almost perfectly with one of carbon dioxide's high absorption region, and a very dense carbon dioxide atmosphere. Thus Venus as come into a temperature equilibrium with a very high temperature because of a very powerful greenhouse effect that depends specifically on the surface temperature of the planet. If Venus were 100 K cooler, its greenhouse effect would be much less...and it would continue to get cooler until it reached some new equilibrium.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Earth&lt;/strong&gt;: On Earth the greenhouse effect is driven primarily by water vapor, not carbon dioxide. Here are the absorption spectra of the two:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jb3xT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jb3xT.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Water vapor is blueish, carbon dioxide is reddish. Note you can see the 4000 &lt;span class=&quot;math-container&quot;&gt;$\mu\text{m}$&lt;/span&gt; carbon dioxide absorption peak here as well. You see that water vapor absorbs more of the spectrum that carbon dioxide, but Earth's peak emissions are in the 10000 &lt;span class=&quot;math-container&quot;&gt;$\mu\text{m}$&lt;/span&gt; range, which you will note is a big gap in both water and carbon dioxide's spectrum; the result is the Earth is relatively cooler. However, the 'water vapor window' noted in the picture shows that carbon dioxide does partially fill this window. As carbon dioxide levels increase from very low to less low, the equilibrium temperature of the Earth will rise. This in turn will bring wavelength down, and move Earth's emission spectrum away from the carbon dioxide absorption, but towards a peak of water absorption. Thus, Earth's greenhouse effect depends heavily on both carbon dioxide and water vapor concentrations in the air. (Again, this doesn't even cover albedo and other things that are critically important)&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Mars&lt;/strong&gt;: Mars has a carbon dioxide partial pressure of around 575 Pa, while Earth is about 40 Pa (at the current ~400 ppm). So Mars' should have a much more significant greenhouse effect than Earth, if CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; level were the only variable. There is a way to determine the projected &lt;a href=&quot;https://en.wikipedia.org/wiki/Effective_temperature#Surface_temperature_of_a_planet&quot; rel=&quot;nofollow noreferrer&quot;&gt;surface temperature of a bare rock planet&lt;/a&gt; based on the Stefan-Boltzman law. Plugging into that equation, Venus' projected temperature is 228 K (low due to high albedo); Earth's is 251 K; Mars' is 212 K. Actual temperatures are Venus 735 K, Earth 287 K, Mars 210 K. While the greenhouse effect is not the only reason for these discrepancies, we can see that Venus has a very high greenhouse effect, Earth has a moderate effect and Mars has none.&lt;/p&gt;&#xA;&lt;h1&gt;Conclusion&lt;/h1&gt;&#xA;&lt;p&gt;Here are the important point from this rundown:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Mars has higher carbon dioxide levels than Earth but less of a greenhouse effect.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Earth has a wider band of greenhouse gas absorption than Venus, but Venus's greenhouse effect is much stronger due to planetary emission spectra lining up with the absorption spectra.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Given the Mars and Venus examples, you can see that for a planet with a primarily CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; atmosphere, variations in planetary temperature would affect the greenhouse effect more than variations in CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; concentration.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I hope you can see from these examples why the interaction between carbon dioxide and the greenhouse effect is too complicated to be modeled in a simple thought experiment.&lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-04-21T21:37:41.000" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="10167" PostTypeId="2" ParentId="10158" CreationDate="2017-04-20T22:27:04.163" Score="2" Body="&lt;p&gt;First things first, I think the spirit of your question, when talking about identical planets with identical solar input but with different atmospheres, you want to ignore albedo.   Albedo's a key component semi-black body or, &lt;a href=&quot;https://en.wikipedia.org/wiki/Planetary_equilibrium_temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;planetary equilibrium temperature&lt;/a&gt; calculation.  Reflected light doesn't warm the object under the sun, only absorbed light.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, if you have very similar planets, same gravity, same atmosphere, same distance from the same sun, but one is black and one is white, the black one would be warmer.   I mention this because snow cover lowers the albedo of a planet and the snow cover is a primary feedback mechanism in the rise and fall of ice ages.   Your question appears to focus primarily on the atmospheric effect, and I'm assuming you want to ignore snow-cover, which no climate model would do.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The height of the atmospheres is the same&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is a bad assumption.   Gas expands when it's warmer.   If you have the warmer planet &quot;G&quot; and the colder planet &quot;N&quot;, you can't assume the height of the atmosphere's are the same.  The troposphere, while a very thin layer of the atmosphere by size, it holds most of the mass of the atmosphere (80% on Earth).   The Troposphere's height is pretty close to directly proportional to temperature.   See &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropopause#Location&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to the height of the stratosphere and mesosphere of the 2 theoretical planets, That's a more tricky calculation.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;so the temperature gradient in the atmosphere will be higher on G. Its&#xA;  lapse rate is higher&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Lapse_rate&quot; rel=&quot;nofollow noreferrer&quot;&gt;lapse rate&lt;/a&gt; applies to the troposphere.   The stratosphere has a different set of rules as it's more affected by the sun's rays than the Earth's stored and radiated heat.   The troposphere grows as the planet warms.  It's higher over the equator than over the poles.   The theoretical planet &quot;G&quot; has the same lapse rate as the planet &quot;N&quot; and a larger troposphere.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What physical parameter can we measure if given ONE planet, without&#xA;  any knowledge of what the conditions are on the other, in order to&#xA;  determine whether we have been given planet G or N?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In other words, you're asking, without measuring the components of a planet's atmosphere, how much can we tell about the surface temperature of two similar planets, G and N by studying the radiation that comes off the planet.   That's a solid question.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A problem with this question is that the components of a planet's atmosphere correspond to specific bands missing from the thermal radiation leaving the planet.   This is an atmosphere's spectroscopic signature.   The greenhouse gases create dark bands in the IR-spectrum of light leaving the planets, so the IR light would have distinctly different signatures.    The net heat leaving planet G and planet N has to be equal but Planet G traps certain wavelengths that planet N does not, so it needs to be warmer to emit the same amount of total energy into space because it has more dark bands across it's IR spectrum leaving the planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More detailed explanation &lt;a href=&quot;https://earthzine.org/2013/12/02/the-far-infrared-spectroscopy-of-the-troposphere-first-instrument-new-technology-for-measuring-earths-energy-balance-and-climate-change-2013-earth-science-technology-showcase/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's a very rough answer anyway.   spectroscopy and heat irradiated from a planet gets complicated.  Actual models of a planet's heat trapping are much more complicated than dark bands missing from the IR spectrum leaving the planet.   If anyone can provide a more detailed explanation please feel free.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;@Gerrit is also right.  It's a bit wonkers to run this calculation without albedo, as that's a huge factor.   But the simple answer is basically the correct one.  Greenhouse gas is a blanket.  More heat gets trapped, and IR has a harder time leaving the surface of the &quot;G&quot; planet, so the planet needs to be warmer on the surface to achieve the same solar radiation into space.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2017-04-20T22:27:04.163" CommentCount="15" ContentLicense="CC BY-SA 3.0" />
  <row Id="10168" PostTypeId="2" ParentId="10158" CreationDate="2017-04-21T00:22:24.890" Score="8" Body="&lt;p&gt;The physical parameters you need to measure to confirm the existence of the greenhouse effect are few and simple. Measure the electromagnetic properties of constituent molecules in the atmosphere. Specifically, look at absorption cross sections as a function of wavelength for solar and terrestrial emission bands. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some molecules will be transparent at solar and terrestrial bands and some will be transparent in some bands and opaque in others. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you can find molecules that are transparent to shortwave but opaque in longwave the you have a molecule that lets energy into the atmosphere but prevents some portion of energy from escaping. This energy that is absorbed causes local heating. This local heating is the green house effect. &lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2017-04-21T00:22:24.890" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="10169" PostTypeId="1" CreationDate="2017-04-21T04:04:23.500" Score="0" ViewCount="92" Body="&lt;p&gt;I was reading &lt;a href=&quot;http://www.climatecentral.org/news/we-just-breached-the-410-parts-per-million-threshold-21372&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; today, and I saw this chart of atmospheric carbon dioxide levels for the past year:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/w56Tv.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/w56Tv.jpg&quot; alt=&quot;Carbon dioxide May 2016-April 2017&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The chart shows a decline in atmospheric carbon dioxide levels from roughly June-October, a cycle that appears to be consistent across &lt;a href=&quot;https://www.esrl.noaa.gov/gmd/ccgg/trends/full.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;many years&lt;/a&gt;: &lt;a href=&quot;https://i.stack.imgur.com/oOuuk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oOuuk.png&quot; alt=&quot;Longer term atmospheric carbon dioxide&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why does this cycle occur? It looks like the period of decline coincides with the season of greatest plant growth in the northern hemisphere. Or is it that energy demand rises so much during the northern-hemisphere winter that the CO2 levels for the entire atmosphere are quickly changed?&lt;/p&gt;&#xA;" OwnerUserId="288" LastActivityDate="2017-04-21T04:04:23.500" Title="Why Do Carbon Dioxide Levels Vary Seasonally?" Tags="|atmosphere|climate-change|" AnswerCount="0" CommentCount="2" ClosedDate="2017-04-21T11:10:12.023" ContentLicense="CC BY-SA 3.0" />
  <row Id="10170" PostTypeId="1" CreationDate="2017-04-21T04:08:40.507" Score="1" ViewCount="98" Body="&lt;p&gt;Dauvillier, through his studies, demonstrate that a rise of 2 degrees, of the average temperature of the planet represents a point of no return, beyond which an irreversible process would trigger, which would bring the earth to become unfit to originate carbon based forms of life. &#xA;My request does not concern the accuracy of the  2°C value, (yet I'm curious of course), but the correctness of the arguments that led Dauvillier to such result. &#xA;Is about to know if the path was the right one, while the exact destination my differ.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would his job, if it were repeated today, in the light of current knowledge, do lead to similar conclusions, or is it based on erroneous assumptions and therefore no longer valid? &lt;/p&gt;&#xA;" OwnerUserId="7946" LastEditorUserId="7946" LastEditDate="2017-04-27T03:43:09.380" LastActivityDate="2017-04-27T03:43:09.380" Title="Is the work &quot;The photochemical origin of life&quot; ,by A.Dauvillier, in line of principle still valid today?" Tags="|climate-change|temperature|history-of-science|" AnswerCount="1" CommentCount="10" ClosedDate="2017-04-26T09:59:05.410" ContentLicense="CC BY-SA 3.0" />
  <row Id="10173" PostTypeId="2" ParentId="10170" CreationDate="2017-04-21T15:15:11.200" Score="2" Body="&lt;h1&gt;Possibly, but they don't apply to today's world&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;I'm reasonably sure, without having read the book but having looked at summaries online, that Dauvillier was arguing that the conditions on Earth when life first developed were such that life would not have developed if the Earth were 2 C warmer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;First of all, you would need to specify from what baseline the 2 C rise was measured. There are many times in the past where the Earth was at least 2 C warmer than the present and covered in advanced life (possibly up to 10 C warmer at time during the Mesozoic). &lt;a href=&quot;https://www.climate.gov/news-features/climate-qa/whats-hottest-earths-ever-been&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA&lt;/a&gt; suggests that parts of the Neoproterzoic saw global temperatures of 90 F and up, and of course life managed to persist through that. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since his book is about biogenesis in general, there isn't much comparison to the conditions on Earth today. On that early Earth where life developed, the sun was much weaker (&lt;a href=&quot;https://en.wikipedia.org/wiki/Faint_young_Sun_paradox&quot; rel=&quot;nofollow noreferrer&quot;&gt;a paradox not completely resolved&lt;/a&gt;). There was no oxygen and much more carbon dioxide, ammonia, and/or methane, depending on who you ask. There were also (obviously) no photosythesizing plants and no biological component to the carbon cycle. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Life has profoundly changed how the Earth &lt;em&gt;is&lt;/em&gt;. The atmospheric dynamics of the early Earth are not comparable to those of our Earth, and thus a 2 C rise then has almost nothing to do with a 2 C rise now. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Again, I haven't read the book so I can't asses what specific theories Dauvillier made about the early Earth. However, it could be possible that both things are true: a 2 C rise 4.5 billion years ago would have sterilized the Earth forever, and a 2 C rise today would not. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2017-04-21T15:15:11.200" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10174" PostTypeId="1" CreationDate="2017-04-21T15:59:58.263" Score="4" ViewCount="59" Body="&lt;p&gt;I find it hard to find information about how the Earth's past climates have been deduced. I know there are archaeological ways of seeing CO2 levels from the past, but to what range can the CO2 levels be understood and at what range can the actual temperature of the area be deduced. How is it definitely known that there were not fast shifts upward and downward in temperatures and CO2 levels in 100 year times spans. I say this understanding that man-made climate change is real, but I want to understand better how to explain it to others and if there are any resources that go in depth into this concept.&lt;/p&gt;&#xA;" OwnerUserId="7952" LastActivityDate="2017-04-21T15:59:58.263" Title="Understanding climate in 100 year intervals" Tags="|climate-change|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10175" PostTypeId="2" ParentId="2521" CreationDate="2017-04-21T16:04:26.973" Score="6" Body="&lt;p&gt;The magnitude of these seasonal variations differ from location to location. The graph below portrays variations in CO&lt;sub&gt;2&lt;/sub&gt; levels at Point Barrow Alaska (PTB), La Jolla California (LJO), Mauna Loa Observatory (MLO), Christmas Island (CHR), Samoa (SAM), and the South Pole (SPO) over the last 60 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XciFD.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XciFD.png&quot; alt=&quot;Graph portraying variations in CO2 levels at six sites over the last 60 years. All of the sites show a general increase in CO2 levels. The northern hemisphere sites also show a marked seasonal variation.&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;Source: &lt;a href=&quot;http://scrippsco2.ucsd.edu/graphics_gallery/other_stations/global_stations_co2_concentration_trends.html&quot; rel=&quot;noreferrer&quot;&gt;Scripps $\text{CO}_2$ Program, Global Stations $\text{CO}_2$ Concentration Trends&lt;/a&gt;.&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that all sites show a general increase in $\text{CO}_2$ concentrations over those 60 years. The sites in the Northern Hemisphere (Point Barrow, La Jolla, and Mauna Loa) also show seasonal variations, with the variations being the greatest at Point Barrow. The sites in the Southern Hemisphere (Christmas Island, Samoa, and the South Pole) show a much reduced seasonal variation, essentially vanishing at Samoa and the South Pole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One reason for these variations is the relatively slow mixing between the northern hemisphere and southern hemisphere atmospheres. It takes about a year for changes in the northern hemisphere atmosphere to make their way into the southern hemisphere atmosphere (and vice versa), and even longer for those northern hemisphere changes to migrate to the South Pole. This slow mixing time means that seasonal variations are confined to the hemisphere in which they occur.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's a large difference between the land to ocean ratio in the northern hemisphere versus the southern hemisphere, and an even greater disparity outside the tropics. The large temperate land mass in the northern hemisphere is the primary cause of those seasonal variations in CO&lt;sub&gt;2&lt;/sub&gt; levels in the northern hemisphere. Plants absorb CO&lt;sub&gt;2&lt;/sub&gt; from the atmosphere in the spring and summer, and release CO&lt;sub&gt;2&lt;/sub&gt; back to the atmosphere in the fall and winter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://scripps.ucsd.edu/programs/keelingcurve/2013/05/07/why-are-seasonal-co2-fluctuations-strongest-in-northern-latitudes/&quot; rel=&quot;noreferrer&quot;&gt;&quot;Why are Seasonal CO&lt;sub&gt;2&lt;/sub&gt; fluctuations strongest at Northern Latitudes?&quot; Scripps Institution of Oceanography&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/JD092iD06p06614/full&quot; rel=&quot;noreferrer&quot;&gt;Daniel James Jacob, et al., &quot;Atmospheric distribution of &lt;sup&gt;85&lt;/sup&gt;Kr simulated with a general circulation model,&quot; Journal of Geophysical Research 92:D6 (1987).&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-04-21T16:04:26.973" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10176" PostTypeId="1" CreationDate="2017-04-21T18:01:15.820" Score="13" ViewCount="661" Body="&lt;p&gt;I have been reading a lot recently about agriculture in Africa, and one of the big impediments in a lot of places is the poor quality of the soil. Primarily this refers to a lack of usable molecular nutrients in the soil that plants need (nitrogen, phosphorous, and potassium, primarily).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand there are a few different methods of soil enrichment; however, these processes are geological in nature. All of the high-population density subsistence agricultural parts of the wet-and-dry tropics are directly correlated to soils that are enriched by one or more of these mechanisms. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first mechanism is direct deposition of nutrients by volcanism from the last hundred million years or so. This is the mechanism responsible for high population densities around the East African rift, Indonesia, Ethiopia, southern India and the Phillipines. The next mechanism is flood plain deposition of eroded materials from somewhere upstream. This is responsible for fertile, high density regions like north India, Egypt, Nigeria, and most of Southeast Asia. These areas have high population densities (of subsistence farmers) other ares in the tropics have very low densities (northern Australia, most of the Sahel, most of southern Africa). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the temperate regions, however, there is a biological means for creating fertile soils. The plains of the American Midwest or Ukraine have had neither recent volcanism nor extensive floodplains, yet are covered in rich, black chernozem soils. Evidently, these soils are produced by the deposition and incomplete decay (due to hard winters) of grasses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is there a biological process that can create rich agricultural soils in either the wet-and-dry tropics?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT&lt;/strong&gt; - Despite the introduction, the purpose of this post is not about agriculture, or what we could do today to to rejuvenate poor soils. This is about natural processes that would take place on timescales of tens or hundreds of thousands of years, or longer. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="6703" LastEditDate="2017-04-24T02:27:11.207" LastActivityDate="2017-04-27T02:44:01.937" Title="How can poor tropical soils be enriched by biological means?" Tags="|geology|soil|soil-science|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10177" PostTypeId="2" ParentId="10160" CreationDate="2017-04-22T00:11:08.360" Score="14" Body="&lt;p&gt;I answered this question on &lt;a href=&quot;https://sustainability.stackexchange.com/questions/5883/why-does-cheese-have-such-a-high-carbon-footprint/5937#5937&quot;&gt;SustainableLiving.SE&lt;/a&gt;. Since no one voted to close this as off-topic, I'll link and summarize my answer here. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm glad you asked for it by calorie, since answers on that question had found the data by kilogram, which is not a particularly useful measure. The data source for carbon per kilogram is the &lt;a href=&quot;http://static.ewg.org/reports/2011/meateaters/pdf/methodology_ewg_meat_eaters_guide_to_health_and_climate_2011.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Meat Eater's Guide&lt;/a&gt; from the Climate Working Group (I believe this is the same as the website you linked, as well); I did the kilogram to calorie calculations from &lt;a href=&quot;http://nutritiondata.self.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;nutritiondata.self.com&lt;/a&gt; which gets its numbers from the FDA.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can read my entire answer, but I will copy the data table for your convenience. Units are kg carbon dioxide emitted per 1000 calories. &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Lamb         20.85&#xA;Beef         13.78&#xA;Turkey        5.83&#xA;Broccoli      5.71&#xA;Tuna          5.26&#xA;Salmon        5.15&#xA;Cheese        4.47&#xA;Pork          4.45&#xA;Yogurt        3.49&#xA;Chicken       3.37&#xA;Milk          3.17&#xA;Eggs          3.06&#xA;Rice          2.08&#xA;Potatoes      1.46&#xA;Beans         1.40&#xA;Tomato        1.39&#xA;Tofu          1.38&#xA;Lentils       0.78&#xA;Peanut Butter 0.42&#xA;Nuts          0.39&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="6703" LastEditDate="2019-12-19T20:21:46.527" LastActivityDate="2019-12-19T20:21:46.527" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="10178" PostTypeId="1" CreationDate="2017-04-22T00:41:55.930" Score="4" ViewCount="2482" Body="&lt;p&gt;On the field, I find it very difficult to differentiate the two types of rocks just by looking at them.I know that you should do some analysis of the sample before any conclusions. But, for example in structural geology, I have to draw a geologic cross section and differentiate sedimentary layers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By looking at pictures I find it very hard to tell whether the rock is limestone or sandstone.&lt;/p&gt;&#xA;" OwnerUserId="7954" LastEditorUserId="725" LastEditDate="2019-04-08T12:38:08.570" LastActivityDate="2019-07-02T02:30:00.170" Title="What are the differences in terms of appearance between sandstone and limestone?" Tags="|geology|sedimentology|petrology|structural-geology|cartography|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="10179" PostTypeId="1" CreationDate="2017-04-22T01:57:38.913" Score="3" ViewCount="113" Body="&lt;p&gt;I was wondering what percentage of precipitation could be estimated to have been contributed by large lakes such as the Great Lakes or Lake Baikal in the immediate vicinity of said lakes (say, within 50-100 miles of the lake)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And generally speaking, what overall percentage of precipitation can be attributed to oceans as opposed to all other sources combined (lakes, rivers, etc)?&lt;/p&gt;&#xA;" OwnerUserId="7955" LastEditorDisplayName="user1066" LastEditDate="2017-04-23T09:14:19.410" LastActivityDate="2017-04-23T09:14:19.410" Title="To what degree do large lakes influence precipitation levels compared to the ocean?" Tags="|meteorology|precipitation|rainfall|mesoscale-meteorology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10180" PostTypeId="2" ParentId="10176" CreationDate="2017-04-22T04:08:25.593" Score="1" Body="&lt;p&gt;Soil enrichment by biological means involves getting biological/organic material into the soil. The organic fraction of a soil profile is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Humus&quot; rel=&quot;nofollow noreferrer&quot;&gt;humus&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a natural process but it can be introduced into agriculture by plowing in crop stubble and other vegetation, whether green or dry. This process can also involve &lt;a href=&quot;https://en.wikipedia.org/wiki/Soil_conditioner&quot; rel=&quot;nofollow noreferrer&quot;&gt;soil conditioning&lt;/a&gt;. Conditioning agents include: blood and bone, straw, coffee grounds, moss, peat sulfur or lime - depending on the requirements of the local soil.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-04-22T04:08:25.593" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10183" PostTypeId="2" ParentId="10157" CreationDate="2017-04-22T15:37:13.080" Score="-1" Body="&lt;p&gt;I think this is it:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;ppm(mol)=ppm(v) x (density CO2/density total atmos) x (Molecular Weight total atmos/Molecular Weight CO2)​​​​.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Try some number crunching to see if that makes sense.&lt;/p&gt;&#xA;" OwnerUserId="7733" LastActivityDate="2017-04-22T15:37:13.080" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10185" PostTypeId="2" ParentId="10176" CreationDate="2017-04-24T02:25:11.657" Score="0" Body="&lt;p&gt;In short....no. If there was such a process, it would have already occurred naturally.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The big limiting factors to creating nutrient rich soils (in a tropical environment) are temperature and moisture. High temperatures keep soil-forming microbiota from turning all of that organic matter into useful, organic matter-rich, &quot;soil&quot;. Most of the biological activity that occurs in soil happens during colder periods of the year. Where heat is year-round, high temperatures propagate fairly deeply into the soil profile, severely limiting the already exothermic process of &quot;composting&quot;: turning leafy plant matter into usable organic material; although &quot;composting&quot; is ridiculously oversimplified!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;High rainfall then strips the soils of much of that biological activity. Most tropical soils, as a result, are merely well rinsed and strained dirt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's a losing game to enrich tropical soil in the hope of creating  conventional agriculture.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastEditorUserId="7333" LastEditDate="2017-04-24T02:31:28.807" LastActivityDate="2017-04-24T02:31:28.807" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10188" PostTypeId="2" ParentId="240" CreationDate="2017-04-24T22:45:54.037" Score="-1" Body="&lt;p&gt;The theory of a Gravity Induced Lapse Rate proposed by Loschmidt (1876) suggests that all planetary bodies will have a temperature gradient in their atmosphere AND in the solid structure of the planet all the way to the core. If this theory is correct then the hot inner core of planets with an atmosphere is a common feature of all such bodies. It is (we think) obviously the case that life does not form on all such bodies but only on a select few. The features of the hot core, cooler surface &amp;amp; gaseous atmosphere would not then be the deciding factor as to whether we have a lifeless planet or not.&#xA;If we assume, like the question, that life requires a certain temperature range then the main deciding factor will be the surface temperature as we expect life to be moving, swimming or flying about pretty close to the surface (generally). The 2 main deciding factors would be distance from the star and composition of the atmosphere, next factor is probably rotational speed on axis. &lt;/p&gt;&#xA;" OwnerUserId="7733" LastActivityDate="2017-04-24T22:45:54.037" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10190" PostTypeId="1" CreationDate="2017-04-25T09:16:37.120" Score="5" ViewCount="478" Body="&lt;p&gt;Is 'nitrification' and 'nitrogen fixation' used interchangeably to describe biological reduction of $\ce{N2}$ gas to $\ce{NH3}$? I know $\ce{NH4} \to \ce{NO3}$ is called nitrification too.&lt;/p&gt;&#xA;" OwnerUserId="7964" LastEditorUserId="2958" LastEditDate="2017-04-26T09:52:58.630" LastActivityDate="2017-04-26T09:52:58.630" Title="Nitrogen cycle semantics; nitrification/nitrogen fixation" Tags="|atmosphere|ocean|biogeochemistry|nitrogen|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10191" PostTypeId="2" ParentId="10176" CreationDate="2017-04-25T09:42:07.990" Score="5" Body="&lt;p&gt;The greatest asset of soils in tropical regions is the organic matter rich 'O-horizon'. Check any reference on soil profiles, they will tell you a lot. Yes, the tropical climate is conducive to excessive rain and leaching of mineral nutrients and salts in upper layers of soil profile that can be observed in a well developed 'E-horizon'. Depending on the local hydrology, not all the nutrients will be lost, just displaced deeper in the soil. Some trees have adapted taproots to access the nutrients deeper in the soil and effectively act as pumps fixing the nutrients to organic matter such as leaves which then fall to the forest floor and deposit the organic form of nutrients ready to be remineralized by detritovores and form a rich surface O-horizon. With that said, an efficient means to trap nutrients in this organic matter cycle is important when dealing with highly weathered mineral soils. Sustaining a heterogeneous forest is important in preserving nutrients and I believe that surface water runoff and erosion can wash away the structure of the nutrient cycling machine. Robust forest structure enhances water infiltration deterring surface water flow and erosion. &lt;/p&gt;&#xA;" OwnerUserId="7964" LastActivityDate="2017-04-25T09:42:07.990" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10192" PostTypeId="2" ParentId="10190" CreationDate="2017-04-25T16:44:36.230" Score="5" Body="&lt;p&gt;I went to do a bit of research on this, and think that you can get a satisfactory answer just from the relevant wikipedia articles. Here are some select quotes:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Nitrogen_fixation&quot; rel=&quot;noreferrer&quot;&gt;Nitrogen fixation&lt;/a&gt; is a process by which nitrogen in the Earth's&#xA;atmosphere is converted into ammonia (NH3) or other molecules&#xA;available to living organisms.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Nitrogen fixation has the chemical process:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;N&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; + 8 H&lt;span class=&quot;math-container&quot;&gt;$^+$&lt;/span&gt; + 8 e&lt;span class=&quot;math-container&quot;&gt;$^−$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\rightarrow$&lt;/span&gt; 2 NH&lt;span class=&quot;math-container&quot;&gt;$_3$&lt;/span&gt; + H&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and is performed by &lt;a href=&quot;https://en.wikipedia.org/wiki/Diazotroph&quot; rel=&quot;noreferrer&quot;&gt;Diazotroph&lt;/a&gt; bacteria or archaea. Some of these are symbiotic with plant roots, especially of the family &lt;a href=&quot;https://en.wikipedia.org/wiki/Fabaceae&quot; rel=&quot;noreferrer&quot;&gt;Fabaceae&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Nitrification&quot; rel=&quot;noreferrer&quot;&gt;Nitrification&lt;/a&gt; is the biological oxidation of ammonia or ammonium to&#xA;nitrite followed by the oxidation of the nitrite to nitrate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;An example of a nitrification chemical reaction is:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;2NH&lt;span class=&quot;math-container&quot;&gt;$_4^+$&lt;/span&gt; +  3O&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\rightarrow$&lt;/span&gt; 2NO&lt;span class=&quot;math-container&quot;&gt;$_2^−$&lt;/span&gt; + 2 H&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;O + 4 H&lt;span class=&quot;math-container&quot;&gt;$^+$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;2NO&lt;span class=&quot;math-container&quot;&gt;$_2^−$&lt;/span&gt; + O&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\rightarrow$&lt;/span&gt; 2 NO&lt;span class=&quot;math-container&quot;&gt;$_3^−$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;There are a wide variety of bacteria that peform these steps, and some only do one step or the other. There are also other pathways for reducing ammonia instead of ammonium, for example.&lt;/p&gt;&#xA;&lt;p&gt;In conclusion, these are two different biologically driven steps in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Nitrogen_cycle&quot; rel=&quot;noreferrer&quot;&gt;nitrogen cycle&lt;/a&gt;, driven by two different sets of microorganims. There other biologically driven processes as well, such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Nitrogen_cycle#Ammonification&quot; rel=&quot;noreferrer&quot;&gt;ammonification&lt;/a&gt;, where organic nitrogen compounds in formerly living tissue (or waste) is broken down into ammonia or ammonium.&lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-04-25T16:44:36.230" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10194" PostTypeId="2" ParentId="9751" CreationDate="2017-04-25T20:25:46.327" Score="3" Body="&lt;p&gt;I would assume that any lightning bolt connecting to the ground would be capable of producing a fulgerite in the soil, regardless of the direction that the bolt &quot;flows&quot;. Fulgerites are caused by the extreme heat of the lightning bolt, which fuses the soil (sand mainly) together into a type of glass. Since the extreme heat of a lightning bolt also causes the sound of thunder, it's safe to assume if you hear thunder from a ground to cloud strike, it can also cause a fulgerite. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most ground to cloud lightning seems to flow from the highest points of very tall objects, such as sky-scrapers, radio towers, etc. Since the best fulgerites are formed in sand, it may be very hard to find a fulgerite caused by ground to cloud lightning. Perhaps on a sandy mountain peak?&lt;/p&gt;&#xA;" OwnerUserId="7967" LastActivityDate="2017-04-25T20:25:46.327" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10195" PostTypeId="2" ParentId="9667" CreationDate="2017-04-25T20:45:53.140" Score="4" Body="&lt;p&gt;Yes, most storm chasers are risking their lives to take lightning photos. Your likelihood of being struck is obviously higher the closer you are to where lightning is originating from. However, lightning is highly unpredictable, and therefore, there is not much you can do to avoid all odds of being struck. One suggestion would be to take photos from inside your vehicle. You could shoot from the back door of a van or truck with a cap, or set your camera outside and operate it with a remote. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would advise against being close to tall objects, as although lightning is more likely to strike it than you, you can still experience deadly charge that reaches you through the ground. &lt;/p&gt;&#xA;" OwnerUserId="7967" LastActivityDate="2017-04-25T20:45:53.140" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10200" PostTypeId="2" ParentId="2533" CreationDate="2017-04-26T06:06:59.653" Score="2" Body="&lt;p&gt;If Canada produced 0.55 (Gt) of $\ce{CO2}$ emissions from 34 million people in 2010,  the per capita emissions is indeed $1.6\times10^{-8}$ Gt of $\ce{CO2}$ per person per year.  This is equivalent to $16$ tons per person per year. &#xA; However, if you want your answer expressed in kg per day, you will needed to multiply by the unit conversions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I confirmed the value of Canadian emissions and that the units are metric tons (not US tons).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are the needed unit conversion ratios:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$1000$ kg / metric ton&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$1$ year / $365$ days&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Notice I wrote the unit conversion ratios such that the desired units are in their proper positions.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, this yields:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$16$ tons / person / per year $\times$ $1000$ kg / ton $\times$ $1$ year / $365$ days = $44$ kg / person / day&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-04-26T06:06:59.653" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10206" PostTypeId="1" CreationDate="2017-04-26T23:07:18.867" Score="-4" ViewCount="626" Body="&lt;p&gt;Irrespective of how accepted any scientific theory happens to be it is often worth thinking about a possible experiment to test said theory and perhaps falsify it. If we wanted to do this for the theory of the greenhouse gas effect what areas are worth considering when designing such an experiment? Would we limit ourselves to just the radiative heat response of CO2 or are their wider issues we need to incorporate into the experiment?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This question is NOT a duplicate as it relates to the generality of greenhouse gases and specifically asks IF we should limit ourselves to the radiative response of CO2. Therefore one possible avenue of answering could be to consider the wider issues of water vapour and methane and such an answer would be clearly outside the scope of the CO2 specific question which has been postulated as the duplicate. &lt;/p&gt;&#xA;" OwnerUserId="7733" LastEditorUserId="7733" LastEditDate="2017-04-30T19:49:10.877" LastActivityDate="2017-04-30T19:49:10.877" Title="Experimental testing to falsify the theory of the greenhouse gas effect" Tags="|atmosphere|climate|climate-change|" AnswerCount="1" CommentCount="14" ClosedDate="2017-05-01T00:23:29.300" ContentLicense="CC BY-SA 3.0" />
  <row Id="10207" PostTypeId="2" ParentId="10176" CreationDate="2017-04-27T02:44:01.937" Score="6" Body="&lt;p&gt;There are two main problems that &quot;wear out&quot; soil, and people working on this deal with both of them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A soil might be low in organic matter and nitrogen, perhaps because all the crops were sold away and the topsoil eroded off. This would also happen on a new sandbank, or where a landslide had revealed a lot of subsoil. Naturally what happens is that the site is colonized by &quot;primary succession&quot; plants that are good at surviving there. These plants photosynthesize carbon compounds, and have bacteriological associates that fix nitrogen out of the atmosphere. The plants and bacteria live and die and leave detritus that slowly turns into richer soil, and somewhat more complex &quot;secondary succession&quot; plants move in. Reclamation agriculture or reforestry helps this along, and &lt;a href=&quot;http://www.worldagroforestry.org/icraf-subject/inga&quot; rel=&quot;noreferrer&quot;&gt;agroforestry&lt;/a&gt; tries to forestall soil loss by growing trees instead of arable crops. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But C and N are not all that plants and bacteria are made of -- just about everything else, eg P and K and Mg and Ca, comes from the geological parent material of the soil. When as anions and cations these elements are being traded and fought over by plants and microbes, they are soluble, and over time they will weather out of the soil. Over geological time they weather out of the underlying rock, which is the problem in the oldest parts of the Earth, and then it's difficult for even primary succession plants to grow. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hawaii is a beautiful natural laboratory for this, as the islands are made of the same lava but are of very different ages. The classic work on this is by Vitousek; here's an open access paper following up on it: &lt;a href=&quot;http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0123995#references&quot; rel=&quot;noreferrer&quot;&gt;Primary Succession on a Hawaiian Dryland Chronosequence&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's a ecology-economy group trying to fix this problem in Haiti. Haiti has exported so much, for historical reasons, that their soil is terrible and they have to import a lot of food although they were recently a very NPP-productive place. &lt;a href=&quot;https://www.oursoil.org/what-we-do/&quot; rel=&quot;noreferrer&quot;&gt;SOIL&lt;/a&gt; works on designing and introducing composting toilets so that the elements imported as food are incorporated into agricultural soil instead of running off (causing public health and fisheries problems as they go!). It's a very nice virtuous-circle, though it takes a lot of work to keep it going. &lt;/p&gt;&#xA;" OwnerUserId="2639" LastActivityDate="2017-04-27T02:44:01.937" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10209" PostTypeId="1" CreationDate="2017-04-27T04:34:46.163" Score="2" ViewCount="185" Body="&lt;p&gt;a) what are the chances, taking into account influencing factors like ocean currents, that these survivors will end up on English shores?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;b) what are the chances, again taking into account all influencing factors, that these survivors will end up anywhere near Africa's rainforest/jungle region? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZrJM4.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="7978" LastEditorUserId="2536" LastEditDate="2017-04-27T05:32:38.537" LastActivityDate="2017-04-28T02:11:19.663" Title="If a ship on its way to Germany from Norway sank, where will the survivors likely end up?" Tags="|ocean|ocean-currents|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10210" PostTypeId="2" ParentId="10209" CreationDate="2017-04-27T05:28:20.163" Score="6" Body="&lt;p&gt;The survivors would probably end up in Jutland or Norway, maybe Sweden due to the currents. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rOQEO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rOQEO.png&quot; alt=&quot;https://de.wikipedia.org/wiki/Nordsee&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://de.wikipedia.org/wiki/Nordsee&quot; rel=&quot;nofollow noreferrer&quot;&gt;CC BY-SA 3.0&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main wind pattern is also western, but with prevailing eastern winds, they might end up in Scotland, depending on the vessel. The Jutlandic coast has experienced a large number of shipwrecks in the past. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6QYQ9.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6QYQ9.gif&quot; alt=&quot;Wind&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;http://www.dmi.dk/vejr/&quot; rel=&quot;nofollow noreferrer&quot;&gt;DMI&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even if a &lt;a href=&quot;https://en.wikipedia.org/wiki/Lifeboat_(shipboard)&quot; rel=&quot;nofollow noreferrer&quot;&gt;boat&lt;/a&gt; gets out on the open ocean, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Gulf_Stream&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gulf stream&lt;/a&gt; flows northeast, so there are very small chances to get to Sub-Saharan Africa. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the answer would be: (a), very small but depending on the survivors' ability to navigate and the wind direction. (b) None. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.newstatesman.com/2015/07/boys-who-could-see-england&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here is a sad account of the North Sea currents&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-04-27T13:41:45.407" LastActivityDate="2017-04-27T13:41:45.407" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10211" PostTypeId="1" CreationDate="2017-04-27T08:06:27.970" Score="9" ViewCount="5153" Body="&lt;p&gt;Why does depletion of underground water levels happening, if the Earth is covered by nearly 78% water, and there is also water in rivers and lakes? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can we still lack groundwater?&lt;/p&gt;&#xA;" OwnerDisplayName="khageshsistu" LastEditorUserId="2536" LastEditDate="2017-04-27T08:38:57.697" LastActivityDate="2017-04-30T02:59:56.853" Title="How can we have groundwater depletion when the Earth is 78% covered with oceans?" Tags="|water|groundwater|water-table|" AnswerCount="6" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10212" PostTypeId="2" ParentId="10211" CreationDate="2017-04-27T08:32:29.397" Score="4" Body="&lt;p&gt;Groundwater is formed from precipitation of rain into the ground. It flows towards the oceans through the soil as the oceans have a lower surface. Often it flows into river and lakes on the way. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the precipitation decreases or water is pumped from the ground for e.g. irrigation, the groundwater table level sinks. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the groundwater becomes lower than the sea surface, salty seawater will flow from the sea under land and destroy potable wells. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope this answers your question. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-04-27T08:42:44.397" LastActivityDate="2017-04-27T08:42:44.397" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10213" PostTypeId="1" CreationDate="2017-04-27T09:14:37.167" Score="4" ViewCount="254" Body="&lt;p&gt;The &lt;a href=&quot;http://www.sciencemag.org/news/2017/04/buried-lasers-will-sense-earths-spin-and-quakes-doing-twist&quot; rel=&quot;noreferrer&quot;&gt;Rotational Motions in Seismology&lt;/a&gt; (ROMY) instrument is a giant laser gyroscope used to generate extremely precise 3D rotation measurements of planet Earth. However at the end of the video below they mention that &quot;seismologists want to...&quot; use small laser gyros to measure seismic tilt motion as part of earthquake monitoring.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a lot of interest in this? Have compelling questions been identified that could be address by adding tilt motion to translational motion monitoring, or is it a case of nobody's looked, there might be something interesting there, better find out?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://youtu.be/MXYV6wNdZm8?t=102&quot; rel=&quot;noreferrer&quot;&gt;https://youtu.be/MXYV6wNdZm8?t=102&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/l4Kn1.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/l4Kn1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2019-02-09T04:05:00.823" LastActivityDate="2019-02-09T04:05:00.823" Title="What (if anything) can be learned from accurately recording tilt motion during seismic events?" Tags="|seismology|earth-rotation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="10214" PostTypeId="2" ParentId="10211" CreationDate="2017-04-27T11:59:51.483" Score="28" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;How can we still lack groundwater?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That 71% of the Earth's surface is covered by oceans is completely irrelevant to the issue of fresh groundwater depletion. Salty groundwater is useless for drinking or irrigating crops.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The issue at hand is the depletion of those underground reserves of fresh water. This depletion can result from natural or human causes. The Sahara is an example of natural depletion. The Sahara was significantly wetter than it is now several thousands of years ago. Rains over the course of a few thousand years created a number of underground reservoirs of fresh water in the Sahara. Rain stopped falling on the Sahara about 7000 years ago. The few remaining oases in the Sahara are places where groundwater still comes close to the surface as a result of that roughly 3000 year long wet spell.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Humans can also cause groundwater depletion. It takes several centuries for rainfall to percolate down to the water table. The replenishment of aquifers is very slow. This is balanced by a very slow trickle from a natural spring here, another one there. The end result is a more or less steady state where the slow replenishment balances the slow outflow. It's very easy to disrupt that balance. Climate change (both natural and anthropogenic) can change the replenishment rate, while artificial wells can drastically increase the depletion rate.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-04-27T11:59:51.483" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10215" PostTypeId="2" ParentId="10154" CreationDate="2017-04-27T15:43:05.177" Score="1" Body="&lt;p&gt;This may/may not actually answer your question &quot;Do warnings verify better&quot; because of the qualitative word &quot;better&quot; and other factors that play a role, such as terrain and forecasting office. Another factor to consider is the nature of the warning and size of the phenomenon. A radar, for example, may not be the best tool to show verification of a hurricane, but it may be better for verification of a tornado. I hope to answer your question by taking arguments to the extreme.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If warnings verify more and more accurately as the warnings get closer to the radar, they may end up in the &quot;cone of silence,&quot; where the angle of the radar would not be able to capture the phenomenon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The opposite of that statement would be that warnings are more accurate the farther away the phenomenon is from the radar. This is also absurd, not only is resolution of the radar cut, but the curvature of the earth also makes this idea absurd.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Conclusion: there is some middle ground. If you get to close, you may not only be endangering your radar (depending on the phenomenon) but you may miss data. It also matters what angle your scan is at. I would hypothesize that anything within the highest elevation angle of the radar would have the highest accuracy, but it would really matter what the phenomenon warned is and what size the phenomenon is. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Warning zones are issued by people, and people have flaws. I would hypothesize that your results may not be conclusive, since the habits of each WFO may vary. For example, a winter storm warning in Georgia is an inch of snow and ice, while Boston would need 6 inches of snow to issue a winter weather watch. Some areas see tornadoes more often than others, leading to some inherent biases, etc.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-04-27T15:43:05.177" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10216" PostTypeId="1" AcceptedAnswerId="10219" CreationDate="2017-04-27T16:28:07.540" Score="4" ViewCount="397" Body="&lt;p&gt;It seems like NOAA used to provide sunshine data from the US weather stations but no longer does.  Is there a reason that was discontinued? &lt;/p&gt;&#xA;" OwnerUserId="7984" LastActivityDate="2017-04-27T19:31:59.990" Title="Why does NOAA no longer provide sunshine data?" Tags="|open-data|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10217" PostTypeId="2" ParentId="10213" CreationDate="2017-04-27T17:30:57.143" Score="3" Body="&lt;p&gt;The intent with this (very, very cool) device seems to simply be to improve hazard assessment and mitigation by providing higher resolution motion data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It reminds me of tiltmeters used on volcanoes. These devices measure changes in the flank slope of a volcano in order to assess volatility and risk (how the magma chamber is developing, etc.).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This kind of technology isn't new, but it's only been available in a precious few places. The ROMY will be able to cover a wide area, but the real holy grail is to have many mobile stations that can record local movements worldwide (as they mention in the video).&lt;/p&gt;&#xA;" OwnerUserId="7939" LastActivityDate="2017-04-27T17:30:57.143" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10218" PostTypeId="2" ParentId="10211" CreationDate="2017-04-27T18:48:58.830" Score="2" Body="&lt;p&gt;Think about elevation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The bottom of the lowest/deepest part of the Ogalala Aquifer is still hundreds of meters above sea level.&lt;/p&gt;&#xA;" OwnerUserId="7988" LastActivityDate="2017-04-27T18:48:58.830" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10219" PostTypeId="2" ParentId="10216" CreationDate="2017-04-27T19:31:59.990" Score="7" Body="&lt;h1&gt;It was not discontinued&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Using the &lt;a href=&quot;https://www.ncdc.noaa.gov/cdo-web/datatools/findstation&quot; rel=&quot;noreferrer&quot;&gt;Climate Data Online&lt;/a&gt; tool from NOAA's website, I was able to get sunshine data through March 1st of this year for both major airports in my metropolitan area. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sunshine data is relatively restricted geographically compared to other datasets like temperature and precipitation (for those I counted 7 stations in my metro area), but you should be able to retrieve data from any major airport. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2017-04-27T19:31:59.990" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10220" PostTypeId="1" AcceptedAnswerId="10228" CreationDate="2017-04-27T19:44:39.547" Score="10" ViewCount="990" Body="&lt;p&gt;I've just learned in &lt;a href=&quot;https://earthscience.stackexchange.com/a/10217/6031&quot;&gt;this answer&lt;/a&gt; that tiltmeters (which I assume measure changes in tilt) are used near active volcanos. (Saw a mention in &lt;a href=&quot;https://earthscience.stackexchange.com/a/4484/6031&quot;&gt;item 4. here&lt;/a&gt; also.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What kind of geological (volcanological?) information can be learned from tilt data? Can it also offer predictive benefits, trigger evacuation warnings?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2017-04-28T16:03:47.130" Title="How are data from tiltmeters used to monitor volcanic activity?" Tags="|volcanology|measurements|volcanic-hazard|field-measurements|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10221" PostTypeId="2" ParentId="10209" CreationDate="2017-04-28T02:11:19.663" Score="3" Body="&lt;p&gt;This may or may not be as relevant to your question, and this isn't really an Earth Science answer, but there is quite a bit of historical information about people surviving sinking ships between Germany and Norway!&#xA;&lt;a href=&quot;https://i.stack.imgur.com/mXRBo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mXRBo.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a list of the &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_ships_sunk_at_the_Battle_of_Jutland&quot; rel=&quot;nofollow noreferrer&quot;&gt;casualties of the battle&lt;/a&gt;. Of particular note, look at the ships that went down without being evacuated.  Of the 5069 British sailors about the five capital ships sunk in the battle, there were 17 survivors. The water temperatures (in May) were so low, that even though destroyers started picking up survivors immediately, almost no one survived. So the answer to your question could be: the survivors won't end up anywhere, since they will likely be dead. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2017-04-28T02:11:19.663" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10223" PostTypeId="2" ParentId="9394" CreationDate="2017-04-28T05:05:22.667" Score="4" Body="&lt;p&gt;Ozone is most closely correlated to temperature.  Yes you need NOx and VOCs to create ozone, but you also need enough photolysis driven by sunlight in order for ozone to form.  The day analyzed in the question is during the middle of winter, which generally does not have enough sunlight to allow ozone to build up in the atmosphere.  Furthermore, when there are high NOx concentrations (and no sunlight), ozone will titrate out of the atmosphere. In contrast, PM2.5 generally reaches it's highest concentrations during the winter (or at night) when the mixing layer is shallow due to cold conditions, which traps particles close to the surface.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are exceptions to these rules though they are rare.  The exception for ozone is when you have very large VOC concentrations (e.g. near an oil field) over a snow layer, because sunlight reflects off the surface and can lead to twice the photolysis.  The exception for PM2.5 is when there are very large sources (e.g. a wildfire) and you get directly within the path of the plume.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-04-28T05:05:22.667" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10225" PostTypeId="2" ParentId="10211" CreationDate="2017-04-28T07:49:06.747" Score="1" Body="&lt;p&gt;As professor A.S.Phillipe says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The cycle of water, this marvelous pump which work with solar energy&#xA;  and affords the alimentation of continent with around  40 000&#xA;  km&lt;sup&gt;3&lt;/sup&gt;/year.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;When seawater evaporates, it becomes fresh and then it's poured on earth it's filtrated by the soils to form an underground reservoir of freshwater neglecting any form of human pollution. &lt;/p&gt;&#xA;" OwnerUserId="7995" LastEditorUserId="725" LastEditDate="2017-04-28T08:26:16.957" LastActivityDate="2017-04-28T08:26:16.957" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10228" PostTypeId="2" ParentId="10220" CreationDate="2017-04-28T15:33:11.503" Score="4" Body="&lt;p&gt;Tiltmeters placed on the flanks of an active volcano can measure changes in the slope angle of the flank. These changes are often inferred to be related to changes in the shape and activity of the magma chamber.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earth-planets-space.springeropen.com/articles/10.5047/eps.2013.03.001&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; provides a quick and dirty example of how these instruments can be used, as well as their limitations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this case, the tiltmeters were able to capture the deflation of an erupting magma chamber, but not the precursory inflation. This leads to some inferences about the nature of the magma's ascent through the subsurface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The article also references studies that were able to detect magma chamber inflation as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These kinds of observations definitely add to the body of evidence volcanologists use to assess risk of an eruption, but it's far from a slam dunk.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Here are some examples from that paper, both the long-term trend, and a higher time resolution display during a small eruption:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5G4r3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5G4r3.jpg&quot; alt=&quot;Fig. 2.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fig. 2. Tiltmeter data from V-net (KRMV, KRHV) and Hi-net (MKNH, SUKH) stations during the period from January 23 to February 2, 2011. From &lt;a href=&quot;https://earth-planets-space.springeropen.com/articles/10.5047/eps.2013.03.001&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PJZ2A.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PJZ2A.jpg&quot; alt=&quot;Fig. 10.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fig. 10. Enlarged view of tiltmeter data during the period from 0:00 to 21:00 on January 26, 2011. Vertical line shows the occurrence time of the small eruption at 7:31 and the beginning of the sub-Plinian eruption, when the amplitude of the seismic tremor increased at 14:49.  From &lt;a href=&quot;https://earth-planets-space.springeropen.com/articles/10.5047/eps.2013.03.001&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="7939" LastEditorUserId="6031" LastEditDate="2017-04-28T16:03:47.130" LastActivityDate="2017-04-28T16:03:47.130" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10229" PostTypeId="2" ParentId="10211" CreationDate="2017-04-28T15:44:14.223" Score="2" Body="&lt;p&gt;I will try to explain it with an analogy. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In one pot pee.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the next pot is water you can drink. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now take a table spoon and move the pee from the pee pot to the drink pot, taking time to sanitize it and turn it back to drinkable water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It doesn't matter how big the pee pot is, 7,000,000 gallons of pee is still only turned into drinkable water one table spoon at a time, so the max you can take from the drink pot is one table spoon (at the same rate your converting your pee).  If you take more then that then your diminishing your drinkable water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The earth is much like our pee pot and drinkable pot example. There is a massive amount of salt water (and non-drinkable fresh water). That's our pee pot. The process of converting that into drinkable water is slow and limited. It takes quite some time to evaporate &quot;dirty&quot; water rain it, for that water to pool, collect and filter, and finely become drinkable. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;No matter the size of the pool of undrinkable water, the drinkable water is only replenished at a very slow and limited rate. If we &quot;use&quot; more drinkable water then is being produced, then it's kinda like drinking our entire drinkable water pot, and peeing back in the pee pot. We still don't have anything to drink.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is a very simple view, and I tired to use a funny, but &quot;gross enough&quot; example to help illustrate. But the fundamentals are the same.&lt;/p&gt;&#xA;" OwnerUserId="8005" LastActivityDate="2017-04-28T15:44:14.223" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10230" PostTypeId="1" CreationDate="2017-04-29T00:25:33.237" Score="3" ViewCount="144" Body="&lt;p&gt;I live in the Piedmont area of Virginia and only an hour and a half from the foothills of the Blue Ridge Mountains.  I recently found a number of what I believe to be petrified wood specimens.  There is also a lot of quartz in the area.  I am curious about the types of rocks, and other geological formations that may be found in my area.&lt;/p&gt;&#xA;" OwnerUserId="8007" LastActivityDate="2017-05-02T02:05:20.123" Title="The Geological make-up in my area" Tags="|geology|regional-geology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10232" PostTypeId="1" CreationDate="2017-04-29T09:04:31.677" Score="5" ViewCount="490" Body="&lt;p&gt;Felsic magmas crystallise in the crust, unlike mafic magmas which tend to make it to the Earth's surface, for the following reasons:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;They are more viscous than mafic magmas and therefore it is mechanically harder to ascend,&lt;/li&gt;&#xA;&lt;li&gt;They are colder, so crystallise earlier, so travel less distance,&lt;/li&gt;&#xA;&lt;li&gt;They are more hydrous than mafic magmas and the loss of water encourages crystallisation .&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;My question is, why does losing water encourage felsic magma to crystallise in the crust? Is it something to do with water being a network modifier?&lt;/p&gt;&#xA;" OwnerUserId="7889" LastEditorUserId="725" LastEditDate="2017-04-30T08:09:30.707" LastActivityDate="2017-04-30T08:09:30.707" Title="Why does the loss of water from a felsic magma encourage crystallisation?" Tags="|water|crust|magmatism|igneous|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10236" PostTypeId="1" AcceptedAnswerId="16227" CreationDate="2017-04-29T13:04:40.333" Score="2" ViewCount="122" Body="&lt;p&gt;I saw something I don't understand in the Gizmodo article &lt;a href=&quot;http://gizmodo.com/cassinis-first-grand-finale-images-are-stunning-but-wha-1794740949&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cassini's First Grand Finale Images Are Stunning—But What Are We Really Looking At?&lt;/a&gt;. In a quote of Caltech Professor of Planetary Science Andrew P. Ingersoll, it is suggested that a it necessary for there to be at least a small tilt between a planet's rotation axis and magnetic axis.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Ingersoll mentioned the final Grand Finale observation he was looking forward to most at the very end of our conversation, which could solve an ongoing mystery of the planet’s formation. Saturn’s magnetic field has a very unusual property in that it’s “axisymmetric”—it has no tilt. That’s weird, because the math behind planetary magnetic fields requires a bit of tilt.&lt;/p&gt;&#xA;&lt;p&gt;“How does a planet generate a magnetic field? The off-axis tilt is sort of part of that whole theory and if there’s no tilt at all, well, it will be interesting,” he said with a chuckle.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Is there a way to understand why a tilt is required in current theories of planetary magnetic fields?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-02-11T09:50:58.197" Title="Why is &quot;at least a small tilt&quot; between rotation and magnetic axis required by models of magnetic field formation?" Tags="|planetary-science|planetary-formation|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="10237" PostTypeId="2" ParentId="9342" CreationDate="2017-04-29T15:41:35.917" Score="3" Body="&lt;p&gt;Every textbook written between about 1930 and say.....now, is pretty useless for your purposes. You'd be better served by watching many of those slick, university produced video lectures. They are filled with great motion diagrams that are un-reproducible in the pages of a two-dimensional book. After all, geosciences are largely about dynamic processes and film is a way better medium for conveying such concepts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Despite Michael's great answer, above, &lt;strong&gt;old geology textbooks are AWESOME!&lt;/strong&gt; I simply cannot convey how fascinating it is to discover the state of ignorance of the world just beneath our feet displayed in many of these books. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My home is festooned with old geology maps, illustrations, and field sketches taken from old folios, USGS reports, and expedition compendiums. I have a 19th century map of Devils Tower that shows the tower in cross section as part of a sill and not the volcanic neck that it is...it's a small detail at the bottom of a map and easily missed, but it's hugely important in interpreting the geology of the area. After all, can you imagine explaining to professional government geologists of the day that they mis-identified the largest iconic piece of geology in the Rocky Mountains?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These old books and texts are a wealth of carefully collected local details which can be used to compare present-day environments with those observed a hundred years ago. Many old reports reference early 19th century expeditionary notes that put the lie to tightly held &quot;truths&quot; repeated here in the desert Southwest.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They are also anthropological treasure troves filled with the state-of-mind of the times: for example, most textbooks view geology strictly in terms of mineral opportunities, others are flights of dinosaur fantasies. European paleontology textbooks are incredible works of art filled with DaVinci-esque illustrations of fossils and their modern counterparts that have yet to be equaled for detail. And the most informative textbooks? Those that expound on evolutionary processes before Darwin. This is all outright fascinating stuff!&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-04-29T15:41:35.917" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10239" PostTypeId="2" ParentId="10230" CreationDate="2017-04-29T15:52:21.603" Score="1" Body="&lt;p&gt;Your local university likely has a small natural history museum in its geology department. These are generally free and filled with information regarding local geology. I'd start there.....and bring your rocks; the attendant might be able to help you find someone who can identify your rocks.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-04-29T15:52:21.603" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10241" PostTypeId="2" ParentId="10236" CreationDate="2017-04-29T16:19:12.660" Score="1" Body="&lt;p&gt;&quot;Tilt&quot; is a consequence of a convecting metal inner core....not a &quot;necessity&quot;. In the earth's case, that tilt has, over time, wandered from 0 to 180 degrees, sometimes with some temporal regularity, other times completely randomly. The science writer likely poorly paraphrased Professor Ingersoll's curiosity regarding the existence of a molten metal core deep within Saturn.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-04-29T16:19:12.660" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10243" PostTypeId="2" ParentId="10211" CreationDate="2017-04-30T02:54:32.937" Score="0" Body="&lt;p&gt;I just want to elaborate a little on groundwater reserves. Below the watertable, the porous rocks within the earth are saturated with either (1) fresh water (2) brine water (contains many dissolved ions and is too salty to drink, sometimes even much saltier than the ocean water), (3) oil, (4) natural gas. The aquifers with potable water are located at shallow depths and get recharged by rain, snow, glacial ice melt etc. It takes many thousands of years for water in these aquifers to accumulate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When an oil well is drilled down to 1-3 km depth, it encounters many aquifers (porous rocks that have pore-spaces filled with water) that are separated by aquicludes (typically mudstones, tight rocks with low permeability that prohibit fluid flow). The shallowest aquifers are typically potable and deep aquifers contain brine water that is not suitable for drinking. The point is that not all underground water is drinkable. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Potable water regulations are different for different places, for example cattle/farm-animal/irrigation water standards are lower than for human drinking (irrigation water is allowed to be a bit more saltier).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The issue is that municipalities extract water from these shallow, good quality aquifers at a much greater rate than they are replenished. Some cities treat and reuse their wastewater (unfortunately this is rare, because people are too squeamish to drink water that once contained pee), while others just keep pulling new water out of the ground/lakes/rivers.&lt;/p&gt;&#xA;" OwnerUserId="7993" LastEditorUserId="7993" LastEditDate="2017-04-30T02:59:56.853" LastActivityDate="2017-04-30T02:59:56.853" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10244" PostTypeId="2" ParentId="10206" CreationDate="2017-04-30T03:04:38.417" Score="6" Body="&lt;p&gt;In the interest of clarifying this a bit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A &lt;strong&gt;Study&lt;/strong&gt; has the purpose of acquiring knowledge.   Many areas of science are fields of study.   Nearly everything NASA does is a study.   NASA may conduct the occasional experiment, but 98%-99% of what they do is for the specific goal of acquiring knowledge, studying the solar system and universe.   The importance of study should not be underestimated.   Many fields in science are studied but not experimented on.  Astronomy for one.  Geology is another one.   Some fields of biology and ecology aren't good for experimental testing, but are still studied.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;An &lt;a href=&quot;http://www.differencebetween.net/language/words-language/difference-between-study-and-experiment/&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Experiment&lt;/strong&gt;&lt;/a&gt;, under proper control has enough test subjects to overcome any numerical coincidence in the outcome, and a set of fixed criteria with one specific thing changed.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can't run true experiments on climate change in the classical experiment sense because we have only one Earth.   We'd need at least two identical Earths to run a proper experiment, and ideally, many more than two.   That's obviously impossible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A &lt;strong&gt;Research Study&lt;/strong&gt; can be an experiment or incorporate one or more experiments, but it also, often isn't an experiment.  While an experiment is generally quite specific, a research study can be more broad.   What your question seems to be asking is about research studies, not experiments.  A good research study leaves an equal chance of either a &quot;yes&quot; and a &quot;no&quot; outcome.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bias research is possible, so lets get that out of the way.  Unbiased research leaves the outcome entirely and fairly up to the results of the study.   Now, a scientist can still have one outcome in mind.  He can even intend to prove something, but that intention doesn't guarantee bias, so long as the study is well outlined and fair.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Climate change has been subject to numerous research studies.  I'll list a few.   My list below is far from complete.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Measure heat in/heat out from space is a basic one.  Satalites measure the heat coming off the earth and the heat coming from the sun.   Changes in heat in/heat out are compared to temperature changes on Earth.   This is a very basic study that could go either way.    It supported greenhouse gas driven climate change.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Temperature change day vs night.    If it's the grenhouse gas, then nights should warm faster than days.   This was studied and nights did warm faster than days.   Another study that supported the greenhouse gas theory. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The &lt;a href=&quot;http://www.nature.com/news/2011/110824/full/news.2011.504.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;cosmic ray/cloud formation&lt;/a&gt; theory.  That cosmic rays could indirectly heat the earth by cloud formation sounded nuts, but it's actually as good a theory as any and it was studied, &lt;a href=&quot;https://home.cern/about/updates/2016/10/cloud-experiment-sharpens-climate-predictions&quot; rel=&quot;nofollow noreferrer&quot;&gt;at CERN no less&lt;/a&gt;.   This study had some merit, but it's insufficient to explain the current warming.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Urban_heat_island&quot; rel=&quot;nofollow noreferrer&quot;&gt;Urban Heat Island&lt;/a&gt;.   In what I consider a hilarious bit of failure, the Koch brothers' funded &lt;a href=&quot;https://en.wikipedia.org/wiki/Berkeley_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Berkeley Earth Study&lt;/a&gt; was designed specifically to avoid any Urban Heat Island warming and disprove climate change.    As I said above, agenda driven research is fine, so long as the research fairly allows the undesired outcome.   Well, that's exactly what their study gave them.  Their research, designed specifically to debunk man made climate change theory produced results that the Earth is warming even faster than NASA's and the IPCC's results.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Studying heat at different altitudes.   Again, if it's the greenhouse gas, more warming should occur lower in the atmosphere, less as you gain altitude.   This is exactly what the study found.  The high altitude temperature readings from UAH and RSS actually support, they don't dispute greenhouse gas driven climate change.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Any one of these research studies could have made a case for or against.   Every one of them, and every research study I've ever read about has supported the man made climate change theory.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Climate change has so much attention, that lots of research has been done.  This isn't a case of one study that everyone agrees with, without proper cross-checking.  It's been tested a dozen different ways a dozen different times and gone over by thousands of scientists and skeptics.  Many studies have been done with the intent to disprove it too.  There's a lot of special interest money out there to oppose the theory and they've failed to provide a single good research study that backs up their alternative theory claim.   There's not one study that produced results against the prevailing theory and many studies in favor.   That's science, not bias.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2017-04-30T07:00:47.250" LastActivityDate="2017-04-30T07:00:47.250" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10245" PostTypeId="1" CreationDate="2017-04-30T05:25:31.493" Score="20" ViewCount="20221" Body="&lt;p&gt;Perhaps a simple question, we know 71% of the earth's surface contains water as oceans. If Earth's age is 4.543 billion years, then I guess it should be decreased with drying or should have been dried so far. Why doesn't it dry or decrease?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we put some water in sunlight, it evaporates. The oceans are the chief source of rain, but lakes and rivers also contribute to it. The sun's heat evaporates the water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I wonder why doesn't the 71% water coverage not evaporate, decreasing until gone? Why is it still 71% after billions of years? Does water keep coming from somewhere? Or, does moving water not evaporate? Why is it still here?&lt;/p&gt;&#xA;" OwnerUserId="8011" LastEditorDisplayName="user12525" LastEditDate="2019-04-19T09:01:52.150" LastActivityDate="2021-01-19T21:51:34.030" Title="Why doesn't the 71% water of the earth dry or evaporate?" Tags="|meteorology|atmosphere|oceanography|water|" AnswerCount="7" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10246" PostTypeId="2" ParentId="10245" CreationDate="2017-04-30T06:57:14.240" Score="46" Body="&lt;p&gt;There are two ways this problem needs to be looked at.   The first is more astronomy than Earth science.  The Earth as an entire system is largely contained.   Its gravity and magnetic field retains nearly all of its elements.   Earth does lose hydrogen and helium and cosmic rays will split water molecules leading to a loss of an impressive amount of hydrogen and as an indirect result a loss of water, but this is loss irrelevant compared to the size of the oceans.    More detail &lt;a href=&quot;https://physics.stackexchange.com/questions/297622/is-the-earth-gaining-or-losing-mass-over-time&quot;&gt;here&lt;/a&gt;.  Space dust, comets and asteroids contain water so some water is returned from space too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By the upper estimate in one article, 50,000 tons of hydrogen per year works out to about 450,000 tons of water lost every year. (and 400,000 tons of oxygen added as a result).    Compared to the mass of Earth's oceans those numbers are small.  450,000 tons per year, or 450 trillion tons over a billion years is nothing compared to the 1.3 million trillion tons of water Earth has in its oceans.   By the highest estimate, it will take 30 billion years at the current rate and at the Sun's current luminosity for Earth to lose just 1% of its oceans.  &lt;em&gt;(Will look to update with other estimates)&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the rest of the question, once we recognize that loss into space is insignificant, then virtually all water is continuously cycled though the &lt;a href=&quot;https://en.wikipedia.org/wiki/Water_cycle&quot; rel=&quot;noreferrer&quot;&gt;water cycle or hydrological cycle&lt;/a&gt;.   Very little water gets destroyed or chemically transformed.   Nearly all of it, even of millions or billions of years, evaporates, or, turns into ice, or gets absorbed by plants, or seeps underground, but it always returns.   Evaporated water returns to Earth as rain.   Water that gets frozen on the ice caps eventually melts back into the oceans.   Water absorbed by plants or that seeps underground does eventually get returned to the surface by plate tectonics or volcanism.   Plants that store water return it when the plant is eaten.  Water is very hard to destroy, so it stays remarkably constant on Earth over time. &lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="5442" LastEditDate="2017-05-01T03:10:20.647" LastActivityDate="2017-05-01T03:10:20.647" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10247" PostTypeId="2" ParentId="10232" CreationDate="2017-04-30T08:08:59.557" Score="2" Body="&lt;p&gt;This answer is based on Winter's presentation for his textbook. Look up chapter 7 on his &lt;a href=&quot;https://www.whitman.edu/geology/winter/JDW_PetClass.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;website&lt;/a&gt;, and start at slide 39.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First let's go through some of your statements:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Felsic magmas crystallise in the crust, unlike mafic magmas which tend to make it to the Earth's surface&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not necessarily. It is true the upper continental crust is composed mostly of felsic intrusive magmas, everything else is not. The lower continental crust, the oceanic crust, arcs, etc., those are all mostly mafic. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;They are more viscous than mafic magmas and therefore it is mechanically harder to ascend&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This only means they ascend slower than mafic magmas. Eventually it all depends on buoyancy. If they're liquid and less dense than the surrounding rocks, they go up.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;They are colder, so crystallise earlier, so travel less distance&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not necessarily. Their final crystallisation temperatures (aka &quot;solidus&quot;) are also lower than mafic magmas. That's why they are liquid at temperatures that mafic melts would already be solid. This has little implication to the distance they travel (to a first order approximation).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;They are more hydrous than mafic magmas...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;True! The reasons for why felsic magmas are (generally) more hydrous than mafic magmas are not important now.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;why does losing water encourage felsic magma to crystallise in the crust? Is it something to do with water being a network modifier?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes. Water, or more precisely, H&lt;sub&gt;2&lt;/sub&gt;O acts as a flux: it is a chemical component that strongly lowers the melting temperatures of various materials, including rocks. It follows the basic chemical reaction of $\ce{rock + H2O = melt-with-H2O-dissolved-in-it}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The important part is that to allow H&lt;sub&gt;2&lt;/sub&gt;O to be dissolved in the melt, you need to have some pressure. Otherwise the H&lt;sub&gt;2&lt;/sub&gt;O just exsolves out and leaves the magma, similar to opening a bottle of carbonated drink (think coke). While there is pressure, the CO&lt;sub&gt;2&lt;/sub&gt; is in the drink. When you open the cap and depressurise it, the CO&lt;sub&gt;2&lt;/sub&gt; comes out of the drink.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Something similar happens in magmas. You have a felsic magma with H&lt;sub&gt;2&lt;/sub&gt;O dissolved in it (otherwise it wouldn't be liquid, it would be solid) rising upwards through the crust. Because it goes up, the pressure around it goes down, causing H&lt;sub&gt;2&lt;/sub&gt;O to leave the magma as bubbles of water vapour (or a supercritical fluid, depending on depth). Then, as the magma loses the flux, it solidifies before it can even reach the surface. Here's a diagram to explain this, in the albite-H&lt;sub&gt;2&lt;/sub&gt;O simplified system, which is a good model for granites and felsic magmas:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Yw0g3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Yw0g3.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At surface pressure (bottom of the diagram) albite melts at slightly above 1100 °C. In a dry system, the higher the pressure, the higher the temperature. For example, at 5 kbar (0.5 GPa) the melting point of albite goes up to 1200 °C. If you add H&lt;sub&gt;2&lt;/sub&gt;O at surface pressures, it doesn't change anything because there is not enough pressure to put the H&lt;sub&gt;2&lt;/sub&gt;O in the (non-existing) melt. But at higher pressure it is possible for H&lt;sub&gt;2&lt;/sub&gt;O to dissolve in the melt, thus allowing the existence of melt. For example at 5 kbar the melting point of albite with more than enough (aka saturated) H&lt;sub&gt;2&lt;/sub&gt;O goes down to 800 °C. That's 400 °C below the dry melting point!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what would happen if a melt containing some H&lt;sub&gt;2&lt;/sub&gt;O starts rising upwards at constant temperature? For example at point a to d in the diagram. It will lose H&lt;sub&gt;2&lt;/sub&gt;O as it rises, increasing the solidus temperature. Because the magma is not hot enough to be liquid at the surface, it will freeze before that, while still at depth.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-04-30T08:08:59.557" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10248" PostTypeId="2" ParentId="10245" CreationDate="2017-04-30T11:12:45.323" Score="25" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Why doesn't 71% water of the earth dry or evaporate?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The simple answer: Because it rains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The not so simple answer: By some estimates, the Earth has already lost about a quarter of its water, and it is predicted to lose almost all of its water in a billion or so years from now.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;It rains because temperature decreases with altitude. This lapse rate means that moist air becomes saturated at some point in the atmosphere. You can see this point on somewhat cloudy days. While cumulus clouds have puffy tops, they have flat bottoms. Those flat bottoms reflect the point where the humidity level reaches 100%.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Currently, only an extremely small fraction of the moisture in the air makes its way to the top of the thermosphere. The tiny amount of moisture that does make its way to the stratosphere can migrate throughout the stratosphere. The top of the stratosphere is unprotected from the nastier parts of the Sun's output. Ultraviolet radiation dissociates water into hydrogen and oxygen. Some of that hydrogen escapes into space. That lost hydrogen represents lost water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth is currently losing about three kilograms of hydrogen into space every second. At that rate, it would take about a trillion (10&lt;sup&gt;12&lt;/sup&gt;) years for the Earth to lose all of its waters. There are signs that the escape rate was significantly higher in the distant past. This is a byproduct of solutions to the Faint Young Sun problem. The signs of this early high escape rate are written in stone (serpentine, to be specific). Very old rocks have a different deuterium ratio that is currently observed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The escape rate will inevitably become significantly higher in the distant future as the Sun gets warmer and warmer. The Earth will eventually lose all of its water.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2017-04-30T11:18:32.770" LastActivityDate="2017-04-30T11:18:32.770" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10250" PostTypeId="2" ParentId="10245" CreationDate="2017-04-30T15:24:19.163" Score="6" Body="&lt;p&gt;There are good answers for this question but Earth Science is one of the few sciences that lends itself really well to experiments around the house. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To see the effect you're talking about (water evaporating, but not going away) take a large rag, and soak it in water. Get it very, very wet. Place the large rag in a zip-lock bag and make sure to seal it tight. Now place the bag with the rag out in the sun.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You will notice how the water never leaves the bag. During the sunny part of the day the water evaporates into the air in the bag, and when there is enough in the air, the water condenses and drips (rains) back down onto the rag.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rag is like the &quot;ground&quot;. The bag is like the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just like with the rag, after water evaporates it &quot;condenses&quot; in the atmosphere (on the bag) and rains (drips) back down to earth (the rag). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a over simplified example of the process, but it demonstrates it very well. &lt;/p&gt;&#xA;" OwnerUserId="8005" LastEditorUserId="8043" LastEditDate="2017-05-02T08:48:28.680" LastActivityDate="2017-05-02T08:48:28.680" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10251" PostTypeId="2" ParentId="10245" CreationDate="2017-04-30T15:46:10.993" Score="5" Body="&lt;p&gt;&quot;If we put some water in sunlight it evaporates.&quot; Really? If I take some water in a closed bottle and put it in the sunlight, then it will evaporate? Obviously not. Why not? Because the air (gas) in the bottle is saturated with water. The relative humidity of that air is 100%, or close to it. You probably know this already. So you should realize that your question is flawed. Not only does water not evaporate in the bottle, but water evaporates at night and inside houses without any sunlight. A better question, imho, is: &quot;Why isn't the Earth's atmosphere saturated with water after 4 billion years?&quot; The atmosphere has a mass of about 5E+18 kg (that is 5 followed by 18 0s, eg 5,000,000,000,000,000,000). The water in the oceans has a mass of about 1.3E+21 kg, meaning about 250 times more mass than the atmosphere. Simply put: there's not enough atmosphere to hold all that water. The reason why the atmosphere is not saturated, does not have 100% relative humidity, is that the temperature of the air varies a lot. Both day to night, and season to season. The air is frequently being cooled and the water lost via precipitation. When this air is reheated, both by direct sunlight and by contact with the surface which warms up even more in direct sunlight, it is low in relative humidity. This is the air that will allow water to evaporate. Because of these temperature cycles, air never has the time to reach saturation.&lt;/p&gt;&#xA;" OwnerUserId="8013" LastEditorUserId="803" LastEditDate="2017-05-02T02:16:41.853" LastActivityDate="2017-05-02T02:16:41.853" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10254" PostTypeId="2" ParentId="10245" CreationDate="2017-04-30T20:29:21.550" Score="8" Body="&lt;p&gt;The bigger question is really: where would it go?&lt;br&gt;&#xA;Because of course matter isn't created or destroyed.  So it'd have to go elsewhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only two places it could go are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Into the Earth.  But water is fairly light (1 g/mL versus Earth which &lt;a href=&quot;http://gfzpublic.gfz-potsdam.de/pubman/item/escidoc:4031:3/component/escidoc:4032/DS_2.1_rev1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;appears to increase&lt;/a&gt; from 1.02 g/mL near the surface to 13.09 g/mL at the center).  Plus, even if water could/did continue to transition into the Earth in large amounts, it'd just build up there until it reached a saturation level.  And there's only so much room between the highly compressed rock.&lt;/li&gt;&#xA;&lt;li&gt;Out to space.  However gravity generally keeps the atmosphere here, just like it does for us.  A very small percentage of gas does escape.  However, it's predominantly lower mass gases like hydrogen and helium.  The question on our site of &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9759/what-g-would-be-needed-to-keep-helium-on-earth/&quot;&gt;What “g” would be needed to keep helium on Earth?&lt;/a&gt; is quite useful for information on this.  &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Or, alternatively,  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Out to space as its constituent gases.  (Monotonic) Oxygen and especially Hydrogen do escape somewhat more readily.  &lt;a href=&quot;https://en.wikipedia.org/wiki/Water_splitting&quot; rel=&quot;nofollow noreferrer&quot;&gt;Electrolysis and other water splitting methods&lt;/a&gt; do cause a small percentage of Earth's water to be broken down at any given time.  However, based upon &lt;a href=&quot;https://scitechdaily.com/earth-loses-50000-tonnes-of-mass-every-year/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this estimate&lt;/a&gt; of 95,000 tons of hydrogen lost per year, and &lt;a href=&quot;http://hypertextbook.com/facts/1998/AvijeetDut.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;this estimate&lt;/a&gt; of $1.4 \times 10^{21}$ kg of water, it'd take &lt;a href=&quot;https://www.wolframalpha.com/input/?i=(1.4*10%5E21%20kg%2F9)%2F(95000%20tons%20to%20kg)&quot; rel=&quot;nofollow noreferrer&quot;&gt;1.8 trillion years&lt;/a&gt; to lose all of Earth's water by hydrogen loss.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Otherwise, if it isn't leaving the system, it could only build up in the atmosphere... potentially until reaching a level where the air could hold no more.  Theoretically that'd be at 100% relative humidity.  Unfortunately the &lt;a href=&quot;http://thevane.gawker.com/explaining-this-weeks-geeky-buzzword-precipitable-wat-1631906844&quot; rel=&quot;nofollow noreferrer&quot;&gt;troposphere can only hold the equivalent of a layer of a couple inches\few cm of water&lt;/a&gt;. Additionally water tends to leaves the air when enough areas of it reach 100% RH, through processes like dew and precipitation.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;And so over the long run, it can only reach an equilibrium, where the amount of water the air held was in balance with the amount it lost.  And that seems in line with what we see.  Moisture levels vary, but aren't rapidly changing in any direction.  Considering that there's &lt;a href=&quot;https://water.usgs.gov/edu/earthhowmuch.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;96000 times more&lt;/a&gt; water in the oceans than there is in the air currently, the atmosphere surely couldn't hold it all anyways!  If it can't leave, and the atmosphere cannot hold it all... well, it has to stay on the Earth.  Certainly we see the equilibrium in practice too, as sea\lake levels aren't dropping consistently.  Lake levels actually vary quite a bit, showing evaporation has the ability to drain at least the lakes fairly fast.  Yet they aren't dropping consistently in any noticeable way.  We're very dry in Florida right now, and lakes are way down... but in places like California and the Piedmont they've been seeing great flooding. But neither lasts in the long run.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looks like &lt;a href=&quot;https://www.sciencedaily.com/releases/2012/03/120305160652.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;studies&lt;/a&gt; do estimate that the Earth has lost 1/4 of its water in its estimated lifetime.  So indeed it's not that nothing leaves.  It's just that it's very slow.  If it wasn't... well we'd be seeing it quickly change now!  Over our lifetimes, over the past few thousand years.  But there's no indications that general lake/ocean levels have drastically changed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do really get that there can be skepticism at billions of years.  It's certainly something we can't verify too easily, visually, personally.  And with Biblical\other religious sources casting potential dispute upon it, that increases the question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Honestly, a reasonable scientist should welcome skepticism and try to address it with fairness and levelheadedness.  Unfortunately there certainly are plenty who are dismissive and belittling, either openly, or in their attitudes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But while questioning is a very worthwhile endeavor, this particular line of reasoning doesn't appear to hold much mustard.  Be wary not to jump too quickly on any potential disagreements you see to accepted theories and thus run hard with them, or you're no different from those overly rigid scientists.  Keep seeking for the truth as something of the greatest value.  Regardless of what it is, and in the end it alone shall stand, and shall set you free!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-05-26T17:16:49.610" LastActivityDate="2018-05-26T17:16:49.610" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="10256" PostTypeId="2" ParentId="10107" CreationDate="2017-04-30T22:42:50.003" Score="1" Body="&lt;p&gt;Most minerals are rare because of two reasons: They are not rare, but they inaccessible, or they require very unusual conditions to form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are some very common minerals in Earth or the universe that we hardly get to see. One of them is moissanite, or silicon carbide (SiC). Both silicon and carbon are very common elements in the universe and they commonly combine to form this mineral. On Earth, however, there is abundant oxygen and both silicon and carbon combine with it instead, so it's rare on Earth. The problem is that space is out there in space, so while it's common in the universe it's rare for us on the surface of our planet. Another example is ringwoodite, the high pressure analogue of olivine. Olivine is one of the most common minerals in the crust, and ringwoodite is one of the most common minerals in the mantle. However, we rarely get to see it up on the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for minerals that require unusual conditions (on Earth), that would be the majority of minerals. The four most important parameters for mineral formation are temperature, pressure (equivalent to depth), chemical environment (i.e. what elements are available) and oxygen fugacity (a measure of how oxidising an environment is). Because a lot of the rocks in the crust form in just a few combinations of these four parameters, few minerals comprise most of the minerals by volume. But then, you can deviate each one of those parameters in so many different combinations, each deviation causing the formation of a different mineral that would be extremely rare. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's an example:&#xA;Tellurium is a rare element, but it forms rather common minerals together with silver and gold. Sylvanite ((Ag,Au)Te&lt;sub&gt;2&lt;/sub&gt;) and petzite (Ag&lt;sub&gt;3&lt;/sub&gt;AuTe&lt;sub&gt;2&lt;/sub&gt;) are probably the two most common. Notice how there is no oxygen there: that's because the geological environments you find tellurium are not those you usually find (enough) oxygen. These minerals are called tellurides. But what if you do find oxygen? You end up having minerals with tellurium and oxygen, and those are names tellurates. These minerals are less common. What if we add some more elements that are even more rare? The Aga Mine in California is one such case where you have tellurium, oxygen, and the addition of the rare lead and copper. This causes for formation of lead-copper-tellurates, extremely rare minerals that occur in only that single mine. Look at the &lt;a href=&quot;https://www.mindat.org/loc-87939.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;list of minerals&lt;/a&gt; found in that mine! Every mineral in bold and (TL) in its name is found only in that single mine. All of them are lead-copper-tellurates, with various proportions of the elements.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-04-30T22:42:50.003" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10257" PostTypeId="1" CreationDate="2017-04-30T22:52:03.863" Score="1" ViewCount="288" Body="&lt;p&gt;My understanding is that it is difficult to measure the amount of radiation the earth receives to the sun and that due to variability in a number of different quantities such as the changing distance to the sun, the tilt of the earth, and the variable amount of radiation emitted from different parts of the sun's surface, it is not currently possible to measure solar irradiance. Is this correct?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastEditorUserId="24481" LastEditDate="2021-09-28T22:15:52.963" LastActivityDate="2021-09-30T05:43:16.670" Title="Is there any way to measure the amount of radiation the earth receives from the sun?" Tags="|measurements|sun|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10259" PostTypeId="2" ParentId="10257" CreationDate="2017-05-01T03:43:18.350" Score="7" Body="&lt;p&gt;Your understanding is half correct. Yes, we can measure the amount of radiation the Earth receives from the Sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, it is difficult to get an &lt;em&gt;extremely&lt;/em&gt; precise measure of how much radiation the Earth receives from the Sun in any one time interval. But there's not really much value in such extreme precision anyway.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it is fairly easy to measure solar irradiance at any one place (on earth, in the atmosphere or in space); as &lt;a href=&quot;https://www.ngdc.noaa.gov/stp/solar/solarirrad.html&quot; rel=&quot;noreferrer&quot;&gt;NASA and others&lt;/a&gt; currently do (kudos to farrenthorpe for the link). These measurements account for the changing distance to the sun, and the tilt of the earth, and to a very large extent the variable amount of radiation emitted from different parts of the sun's surface, because the Sun's diameter is tiny compared to the distance between the Earth and the Sun (just under 1%).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And having measured solar irradiance at one or more places, it is then easy to get a fairly precise estimate of how much radiation the Earth receives from the Sun in any one time interval.&lt;/p&gt;&#xA;" OwnerUserId="100" LastActivityDate="2017-05-01T03:43:18.350" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10260" PostTypeId="1" CreationDate="2017-05-01T06:11:07.653" Score="5" ViewCount="103" Body="&lt;p&gt;Can the change in composition from basanite to nephelinite (i.e. increasing alkalis with decreasing SiO2) be explained in terms of fractional crystallisation, or only by a decreasing degree of partial melting? If the latter, does the silica content decrease because it is compatible and therefore isn't enriched in the melt?&lt;/p&gt;&#xA;" OwnerUserId="8023" LastEditorUserId="2470" LastEditDate="2017-05-01T12:41:59.143" LastActivityDate="2017-05-01T12:41:59.143" Title="What causes a change in composition from basanite to nephelinite?" Tags="|geology|geochemistry|petrology|magmatism|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10261" PostTypeId="1" AcceptedAnswerId="10277" CreationDate="2017-05-01T12:09:21.857" Score="3" ViewCount="281" Body="&lt;p&gt;Most people are well aware of the idea of greenhouse warming. Carbon dioxide receives particular attention, do to the uncertainty of sources, sinks, and inert properties. However, combustion, which produces carbon dioxide, also produces water vapor, another greenhouse gas. I am aware of the paper on contrails, but generalizing that idea beyond contrails.&#xA;Given that water vapor is a greenhouse gas, and assuming the produced quantities are comparable to the quantities of carbon dioxide produced, has there been a study using climate models, with only water vapor emissions inventories, as compared to only carbon dioxide emissions inventories?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A second aspect to this is thermal aspects of anthropogenic steam. Because steam is produced with a temperature higher than the environment, how much of an impact does the mixing of this steam have on the climate, particularly the microclimate?&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="2470" LastEditDate="2017-05-01T12:39:50.783" LastActivityDate="2017-05-02T13:13:16.320" Title="Has there ever been a study done on the effect of steam/thermal pollution on climate" Tags="|climate|water-vapour|" AnswerCount="1" CommentCount="5" ClosedDate="2017-05-02T14:13:40.447" ContentLicense="CC BY-SA 3.0" />
  <row Id="10262" PostTypeId="1" CreationDate="2017-05-01T12:13:34.297" Score="3" ViewCount="57" Body="&lt;p&gt;Beyond creating a closed ecological system - that focuses on providing a balanced homeostatic environment - what is the smallest area that could create actual weather events?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we wanted to engineer a rain fall through simulating the environmental conditions, would the structure need to be the size of a planet and its atmosphere? Can it be achieved in a structure the size of a continent... a state... a sports stadium? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What methods could be used to estimate the minimum size; volume of air, altitude, barometric pressure areas, etc.?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am trying to understand how to identify a theoretical lower limit of recreating a functional weather system. Not just a simulation of the conditions on a micro scale.&lt;/p&gt;&#xA;" OwnerUserId="5950" LastEditorUserId="5950" LastEditDate="2017-05-01T12:56:34.990" LastActivityDate="2017-05-01T12:56:34.990" Title="What is the minimum area needed to create a functional weather system?" Tags="|meteorology|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10263" PostTypeId="2" ParentId="10107" CreationDate="2017-05-01T12:58:43.030" Score="2" Body="&lt;p&gt;Mineral rarity is dependent on several factors that include these:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Distribution of elements within the earth&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The mass-abundance of the nine most abundant elements in the Earth's crust is approximately: oxygen 46%, silicon 28%, aluminum 8.2%, iron 5.6%, calcium 4.2%, sodium 2.5%, magnesium 2.4%, potassium 2.0%, and titanium 0.61%. Other elements occur at less than 0.15%. (&lt;a href=&quot;https://www.google.com/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=3&amp;amp;cad=rja&amp;amp;uact=8&amp;amp;ved=0ahUKEwjCtar61s7TAhWr4IMKHWBxB9QQFggvMAI&amp;amp;url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FAbundance_of_the_chemical_elements&amp;amp;usg=AFQjCNHvd-qd8oFW9IF0stR3FpIx1IHgOQ&amp;amp;sig2=YNlpJVTw5QVsRc4LfkS2Gg&quot; rel=&quot;nofollow noreferrer&quot;&gt;reference&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So minerals composed of elements other than (O, Si, Al, Fe, Ca, Na, Mg, K, and Ti) represent far less than 0.15% chemical composition of the earth.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Redistribution of elements by natural processes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider the top 9 elements (O, Si, Al, Fe, Ca, Na, Mg, K, Ti), notice Chlorine is not in the list but by mass Cl should be in the top 9 for the surface of the earth.  Natural processes will alter the distribution of elements.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Top elements in the oceans (71%) of earth's surface are:&#xA;Oxygen, hydrogen, chlorine, sodium, magnesium, sulfur, calcium, potassium, bromine, carbon, and boron.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Atmospheric elements are: Oxygen, Carbon, Hydrogen,Nitrogen ,Calcium, Potassium&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Stability (physical and chemical characteristics) of mineral species can affect how common a mineral may be.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Example: Water soluble mineral species - There are at least 90 mineral species that readily dissolve in water.  (&lt;a href=&quot;http://www.johnbetts-fineminerals.com/jhbnyc/soluble.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;reference&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some minerals are solution readily affected by acidic or alkali solutions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some minerals are inherently unstable are near surface conditions.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Some minerals readily oxidize  (native iron)&lt;/li&gt;&#xA;&lt;li&gt;Some minerals can slowly altered by humidity and oxygen (marcasite)&lt;/li&gt;&#xA;&lt;li&gt;Some minerals are only stable at high tempature and/or pressure.&#xA;(It depends on the crystal structure of the mineral how long the mineral remain at surface conditions (1 atm pressure 25'C)&#xA;Diamonds are resilient but alpha-Quartz can rapidly alter to beta-Quartz. &lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Mineral formation environments impact mineral distribution.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Minerals that commonly form in the mantle of the earth are naturally going to hard to find at the surface regardless of the chemical position.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Volcanic mineral assemblies require a volcanic activity which is typically limited to plate boundaries and isolated mantle hot spots.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Lastly thermodynamics (Gibbs free energy) can be used to measure the how probability of specific chemical reaction is occur.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider:  Fe + S = FeS2  (pyrite)  verses Fe + S = FeS2  (marcasite)&#xA;Free energy state of an environment can be used to explain why pyrite or marcasite will form.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Some chemical reactions are very improbable due to elements involved with in a specific environment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider:&lt;br&gt;&#xA;   Cubic zirconia (CZ) is the cubic crystalline form of zirconium dioxide (ZrO2). It is not found in nature because there are no stable environments for formation where Silicon is absent.   Zircons are formed instead. (zirconium silicate (ZrSiO4). &lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="1149" LastEditDate="2017-11-04T18:26:56.697" LastActivityDate="2017-11-04T18:26:56.697" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10265" PostTypeId="1" AcceptedAnswerId="10295" CreationDate="2017-05-01T17:26:52.373" Score="3" ViewCount="58" Body="&lt;p&gt;I am trying to find any published (not wiki) source of information about how many times and when exactly the Bering Land Mass was free of water. Everything that I find is just pieces of information in different papers, one contradicting another. Is there any source that can be cited reliably in scientific literature with a timeline or something like a summary table? &lt;/p&gt;&#xA;" OwnerUserId="8025" LastEditorUserId="2470" LastEditDate="2017-05-01T17:33:47.200" LastActivityDate="2017-05-04T02:14:46.560" Title="Beringia - history of the region, periods of sea level fall/rise - paleogeography of Pleistocene" Tags="|sea-level|ice-age|paleogeography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10266" PostTypeId="1" CreationDate="2017-05-01T20:20:27.883" Score="3" ViewCount="64" Body="&lt;p&gt;Are there any published descriptions of simple equations governing the formation, evolution, and decay of severe storms?  Specifically, I am interested in equations that are able to produce tornadoes with funnel clouds, and output volumetric moisture data.  It does not need to be meteorologically accurate, but should be able to be applied and, coupled with accurate volumetric rendering, produce visually compelling storms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have reviewed all &lt;a href=&quot;/questions/tagged/simulation&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged &amp;#39;simulation&amp;#39;&quot; rel=&quot;tag&quot;&gt;simulation&lt;/a&gt; questions on this site, and have also reviewed both the &lt;a href=&quot;http://www.wrf-model.org/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;WRF&lt;/a&gt; and &lt;a href=&quot;http://www2.mmm.ucar.edu/people/bryan/cm1/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CM1&lt;/a&gt; projects.  The former appears to focus more on forecast-relevant prediction (e.g. total rainfall), and the latter lacks documentation and code comments (and is written in Fortran), making it useless for adaptation in my own simulation.&lt;/p&gt;&#xA;" OwnerUserId="8035" LastActivityDate="2017-05-01T20:20:27.883" Title="Visually Realistic Supercell Modeling" Tags="|numerical-modelling|severe-weather|tornado|simulation|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10267" PostTypeId="2" ParentId="10230" CreationDate="2017-05-02T02:05:20.123" Score="0" Body="&lt;p&gt;The Roadside Geology of Virginia by Keith Frye is one of a series of books about geology in different states. It probably would be a good place to start to explore different geologic features.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-05-02T02:05:20.123" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10268" PostTypeId="1" CreationDate="2017-05-02T03:55:12.353" Score="1" ViewCount="1455" Body="&lt;p&gt;I was going to ask a question about why the sun is not due south at noon throughout the year.  There was a discussion on this site about daylight savings time, GMT, longitude, time zone boundaries and train schedules.  I found a very interesting and more astronomical explanation here: &lt;a href=&quot;https://darkskydiary.wordpress.com/2011/06/13/the-equation-of-time/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://darkskydiary.wordpress.com/2011/06/13/the-equation-of-time/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8038" LastActivityDate="2017-05-02T03:55:12.353" Title="Why isn't the sun due south at noon?" Tags="|sun|time|" AnswerCount="0" CommentCount="3" ClosedDate="2017-05-02T07:57:12.370" ContentLicense="CC BY-SA 3.0" />
  <row Id="10271" PostTypeId="1" CreationDate="2017-05-02T09:41:32.027" Score="4" ViewCount="66" Body="&lt;p&gt;Using Pressure sensors - I found out that there is a daily pressure wave-like pattern with peaks at 9:00 &amp;amp; 21:00 (local time).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to construct an equation to explain this phenomena, probably something that relates the solar radiation and the latitude to the pressure measurement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone refer me to a model or articles regarding this ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks ! &lt;/p&gt;&#xA;" OwnerUserId="8049" LastActivityDate="2017-05-02T09:41:32.027" Title="Equation for Atmospheric Pressure Tide" Tags="|meteorology|atmosphere|atmosphere-modelling|barometric-pressure|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="10272" PostTypeId="1" AcceptedAnswerId="22440" CreationDate="2017-05-02T10:21:49.307" Score="4" ViewCount="4560" Body="&lt;p&gt;I've been reading up about Gravitational Models and Spherical Harmonics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where I first read about them is in this &lt;a href=&quot;https://arxiv.org/pdf/1609.05225.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;scholarly article&lt;/a&gt; on Autonomous navigation with Gravity Gradients. It talks about Gravity Models being of order &lt;em&gt;x&lt;/em&gt; and degree &lt;em&gt;y&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What does &lt;strong&gt;order&lt;/strong&gt; and &lt;strong&gt;degree&lt;/strong&gt; mean in this circumstance? Is it something to do with the Lagrangian Polynomials used in the models?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another example is found &lt;a href=&quot;http://earth-info.nga.mil/GandG/wgs84/gravitymod/egm2008/egm08_wgs84.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; which states that EGM2008 is complete to spherical harmonic degree and order 2159&lt;/p&gt;&#xA;" OwnerUserId="8051" LastActivityDate="2021-06-22T13:09:14.683" Title="What does the degree and order of Spherical Harmonics mean?" Tags="|models|gravity|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10273" PostTypeId="1" CreationDate="2017-05-02T11:28:36.640" Score="3" ViewCount="328" Body="&lt;p&gt;I am trying to understand PKN and KGD models for hydraulic fracturing. I am wondering why equations for fracture width and length does not include 'breakdown pressure' (pressure at which fracture initiates? The formula for fracture length for KGD is $$X_f=0.48[\frac{8GQ^3}{(1-v)\mu h_f^4}]^\frac{1}{6} t^\frac{2}{3} $$ where G, Q, $\mu$, $h_f$ and t are shear modulus, injection rate, viscosity, fracture height and time respectivily. Why there is not a threshold value, after which fracture initiates in this formula?&lt;/p&gt;&#xA;" OwnerUserId="5557" LastActivityDate="2017-05-02T11:28:36.640" Title="measuring fracture length and width using PKN and KGD models for hydraulic fracturing?" Tags="|geophysics|geodynamics|structural-geology|fracking|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10274" PostTypeId="2" ParentId="10272" CreationDate="2017-05-02T12:51:34.047" Score="4" Body="&lt;p&gt;It's Legendre polynomials, not Lagrangian.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The zonal harmonics (the $Y^0_l$ terms) depend only on latitude. These zonal harmonics are closely associated with the Legendre polynomials $P_l(x)$, where $x$ is the sine of the geocentric latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The tesseral and sectoral harmonics (the $Y^m_l$ terms, where $m\ne 0$) are closely associated with the associated Legendre functions $P_{lm}(x)$.  (Note: These are sometimes called associated Legendre polynomials, but they aren't polynomials.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Spherical harmonics are widely used in physics, so the presentations readily found on the internet generally reflect how physicists use spherical harmonics. There are some key differences between these easily found references on the internet and the forms used to represent gravitation. One is that physicists typically use colatitude, and hence use $P_l(\cos\theta)$ as opposed to $P_l(\sin\phi)$. Another is that physicists tend to use the complex form, while gravity models are expressed in terms of real sine and cosine forms. Finally, a set of gravity coefficients is inevitably going to be fully normalized coefficients, while physicists use a form with a different normalization.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-05-02T12:51:34.047" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10277" PostTypeId="2" ParentId="10261" CreationDate="2017-05-02T13:13:16.320" Score="2" Body="&lt;p&gt;While the effect might be measurable (just barely) it's small.   We add about 30 billion tons of CO2 to the air every year.   About half of that gets absorbed into the oceans (give or take), the remaining 15 billion tons remains in the atmosphere for a long time.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;280 PPM CO2 the post ice-age, pre industrial revolution number works out to about 1,000 billion tons of CO2.   Adding 15 billion tons per year, at the current rate, it would take about 66 years to double the 280 PPM to 560 PPM.   That's, of-course, very much an approximation and the ocean absorption rate probably doesn't remain constant it depends on the change in concentration and change in ocean temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Water vapor, however.   While the output varies depending on fuel the mass of water added by burning fossil fuels is about 1/2 the mass of CO2, so 15 billion tons per year.   The amount of water vapor in the atmosphere at any given time is by &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Earth#Density_and_mass&quot; rel=&quot;nofollow noreferrer&quot;&gt;this estimate&lt;/a&gt; about 5,700 billion tons.    Adding 15 billion tons of water vapor to the atmosphere per year might be enough to be significant, but as pointed out in the comments, water vapor leaves the atmosphere very quickly.  Unlike CO2, which takes a long time to filter out.   The half-life of water is days, the half-life of CO2 is probably a century or more.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If extensive driving or fossil fuel burning is done in low humidity areas, it seems feasible that some warming could be added by the increase in water vapor, but I expect that effect would be small but perhaps measurable.   In high humidity areas it would be irrelevant.   I've never heard of a study that looked at this in any detail.    That said, the intuitively obvious answer is that the effect would be tiny.   A tiny fraction of of the effect of CO2.    That said, water vapor does need to be included in the study as warmer temperatures hold more water vapor, so, as the Earth warms, water vapor in the atmosphere increases and pushes the warming along even more.   That's a well known feedback mechanism.    The effect of water from burning fossil fuels is likely very tiny because it's too little and too temporary and the net total amount of water vapor in the air is still primarily a factor of temperature, weather patterns and wind direction.    It is, however, probably not zero.  There's likely some tiny effect, but I've never heard of a study that looked into it.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2017-05-02T13:13:16.320" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10279" PostTypeId="2" ParentId="10245" CreationDate="2017-05-02T14:13:39.667" Score="0" Body="&lt;p&gt;I don't want to post a super long answer so I'll keep it simple.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pressure and gravity due to the mass of the earth keeps the water within the atmosphere and cycling through the 3 states of solid, liquid, and gas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Our water is constantly being recycled, and some things create water, like humans (we create water in our lungs when we breathe.)&lt;/p&gt;&#xA;" OwnerUserId="8059" LastActivityDate="2017-05-02T14:13:39.667" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10281" PostTypeId="1" CreationDate="2017-05-02T15:34:09.813" Score="5" ViewCount="80" Body="&lt;p&gt;If we move far enough into the future that the core begins to solidify to the point that volcanism and tectonics are non-existent, what does the surface of the planet begin to look like?  Does the planet eventually become fully covered in water due to erosion?&lt;/p&gt;&#xA;" OwnerUserId="8061" LastActivityDate="2017-05-02T15:34:09.813" Title="What happens to the earth after volcanism/tectonics slows?" Tags="|volcanology|tectonics|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10282" PostTypeId="1" CreationDate="2017-05-02T17:03:17.827" Score="4" ViewCount="1623" Body="&lt;p&gt;If we can use the Stefan-Boltzman equation to quantify the radiative flux leaving a solid body due to emission of radiation and to do it properly for a solid body we need to include the emissivity term then why, when considering the radiation emitted by the gas CO2 in the atmosphere, do we not use the SB equation utilising the absolute temperature of the atmospheric gas and the emissivity of CO2? The emissivity of CO2 is, I think, something like 0.002 (depends on temperature/pressure).&lt;/p&gt;&#xA;" OwnerUserId="7733" LastEditorUserId="6703" LastEditDate="2017-05-02T20:08:37.880" LastActivityDate="2017-05-05T21:39:39.640" Title="How do we apply the Stefan-Boltzmann equation to radiative heat transfer from/to CO2 in the atmosphere?" Tags="|atmosphere|climate|climate-change|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10283" PostTypeId="2" ParentId="9618" CreationDate="2017-05-02T18:04:28.540" Score="-5" Body="&lt;p&gt;Climate science is a very exciting field to get into right now. Not only do we have a change at the top in politics in the USA and the prospect of big changes there but the new theory of a Gravity Induced Temperature Gradient is coming to the fore. I recommend researching and reading about both sides of the debate, not just the CAGW theory stuff. If the ideas of Loschmidt (c.1870's) and the recent experimental results of R.Graeff (2007) take precedence over the current consensus theories then there will be great opportunities opening up in this field for those with the right knowledge and background. Good luck with it !   &lt;/p&gt;&#xA;" OwnerUserId="7733" LastActivityDate="2017-05-02T18:04:28.540" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10285" PostTypeId="2" ParentId="10282" CreationDate="2017-05-02T20:50:17.667" Score="6" Body="&lt;h1&gt;We don't&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Emissivity of CO$_2$&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your claim of low emissivity of CO$_2$ is not entirely true. First off, it matters what the wavelength of emission is when determining emissivity. Carbon dioxide has specific bands of high absorption (which correspond to high emissivity). These bands are crucial for climate modeling, so listing a numerical emissivity value without specifying the wavelength is not a useful measurement. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly, emissivity of a gas isn't as simple as that of a solid surface because solid surfaces are more or less opaque to the IR radiation emitted in accordance with the Stefan-Boltzman equation. Therefore, the surface area of the 'blackbody' is what is important when calculation emission or absorption. For a gas, however, IR radiation will penetrate some distance through it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The result is that you need to calculate emissivity of a gas as a function of its optical depth. &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0450(1970)009%3C0365:FETFWV%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Staley and Jurica, 1970&lt;/a&gt; present calculations where they do that for carbon dioxide in the 15 $\mu$m absorption band (the most important one for climate models). Their results show that at 20 C, CO$_2$ has an emissivity of 0.0823 at an optical depth of 1 cm; 0.244 at an optical depth of 10 m; etc. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Spectrum matters&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I mentioned above, the emission spectra matters a lot. In the case of CO$_2$, there is a specific emission band which corresponds to the absorption band. This means that any radiation emitted by CO$_2$ is emitted at just the perfect wavelength to be reabsorbed by other molecules of CO$_2$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;CO$_2$ also differs from water vapor in that it remains dispersed through the atmosphere and doesn't coalesce into weather formations. Water vapor aggregates into clouds; the emissions from those clouds can be significant because there is much more water vapor emitting in a cloud than in the (drier) air above the cloud. CO$_2$ doesn't exhibit that behavior and thus its emissions are mostly trapped by other CO$_2$, whereas blackbody emission from cloud banks can be significant on the global scale. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What does get emitted to space and lost is heavily attenuated by the presence of other CO$_2$ molecules and is insignificant compared to emissions from the Earth's surface, which pass through the absorption band gaps in water vapor and CO$_2$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Conclusion&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't actually know what factors each specific climate model uses. There may be some that account for the emissivity of CO$_2$. It may be that &lt;em&gt;all&lt;/em&gt; the models account for it; it has been over a decade since I contributed to those models. However, whether they account for it or not, it is not a significant factor in driving temperature changes the way the emissivity of the Earth's surface is. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="6703" LastEditDate="2017-05-03T12:01:31.300" LastActivityDate="2017-05-03T12:01:31.300" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10286" PostTypeId="1" AcceptedAnswerId="10287" CreationDate="2017-05-02T21:01:21.407" Score="4" ViewCount="489" Body="&lt;p&gt;In my text book I came across this multiple-choice question&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A sedimentary rock consists of only minerals and lacks fossils, it could be classified as:&lt;/p&gt;&#xA;&lt;p&gt;i) a clastic sedimentary rock&lt;/p&gt;&#xA;&lt;p&gt;ii) a chemical sedimentary rock&lt;/p&gt;&#xA;&lt;p&gt;iii) a biochemical sedimentary rock&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Of course I would exclude &amp;quot;a biochemical&amp;quot;, but I am confused between &lt;em&gt;clastic&lt;/em&gt; and &lt;em&gt;chemical&lt;/em&gt;. I did some research on google but didn't find a precise answer. However, I found that both of them could contain only minerals.&#xA;So, I hope someone could help me here!&lt;/p&gt;&#xA;" OwnerUserId="6908" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-05-02T23:23:36.110" Title="A sedimentary rock with only minerals" Tags="|geology|mineralogy|sedimentology|homework|fossils|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10287" PostTypeId="2" ParentId="10286" CreationDate="2017-05-02T23:23:36.110" Score="5" Body="&lt;p&gt;This is a really bad question, because all three can lack fossils, or all three can have fossils. The definition of &quot;minerals&quot; is also a bit unclear, because fossils are also made out of minerals. I'll assume that by minerals they mean non-biogenic minerals. Let's go through each one of them:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;a clastic sedimentary rock&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This rock will have minerals, because this is what is being transported. Usually quartz, feldspars, clays, heavy minerals, etc. But, it can also have fossils. Fossils can be transported as well, and it is not uncommon to find fossils in clastic sedimentary rocks. They are usually not intact, but still fossils nonetheless.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;a chemical sedimentary rock&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This will have minerals, obviously. This might also have fossils: what if there were organisms around while the chemical rock formed? Could be fossils falling from above into a carbonate precipitate, or insects in an evaporite basin. However, this is probably the least likely rock to contain fossils. If you have to choose only one, this would be it (unfortunately).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;iii) a biochemical sedimentary rock&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This sounds like an obvious one to contain fossils, but it may not be. What about limestones where all of the fossils were broken down to unrecognizable fragments of calcite? Also known as a micrite? This would be biogenic, but it wouldn't be clear what fossils are there.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-05-02T23:23:36.110" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10289" PostTypeId="1" CreationDate="2017-05-03T08:25:18.777" Score="3" ViewCount="367" Body="&lt;p&gt;I read &lt;a href=&quot;http://www.thehealthyhomeeconomist.com/organic-hydroponic-produce-not-for-me/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt;, in which a person claims that Aquaponics bring crop quality down by having more water than actual nutritional value. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have read many other sources that say the opposite. Can anyone guide me towards the research that says that aquaponics/hydroponics yields crops with lower nutritional value? I couldn't find open access peer reviewed articles that say as much, but maybe I left a stone unturned.&lt;/p&gt;&#xA;" OwnerUserId="7978" LastEditorUserId="5594" LastEditDate="2017-05-03T15:38:56.400" LastActivityDate="2020-10-10T18:25:31.150" Title="Is it true that aquaponics yield crops with a lower nutritional value than soil-agriculture?" Tags="|water|soil|agriculture|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10290" PostTypeId="1" CreationDate="2017-05-03T12:19:19.963" Score="5" ViewCount="1241" Body="&lt;p&gt;The part of the earth tilted towards the sun is warmer. For example, in the Northern hemisphere, the earth is tilted towards the sun in the months around June and tilted away from it in the months around December. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;This has the effect of increasing the exposure of the earth to the sun for the latitudes tilted towards the sun. &lt;/li&gt;&#xA;&lt;li&gt;Also, the more tropical the latitude, the more energy is received per unit area.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;These two ideas are illustrated by the figure below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YRjyP.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YRjyP.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/eZozw.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eZozw.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are other effects, too...&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;If the sun's energy must pass through more atmosphere, there is greater opportunity for it to scatter into space before reaching the earth&lt;/li&gt;&#xA;&lt;li&gt;When the sun strikes the earth, if it strikes it obliquely there is greater chance for the light to be reflected rather than absorbed.&lt;/li&gt;&#xA;&lt;li&gt;Finally, whether the sun strikes water or land or ice has an effect, because each has a different degree of absorption and reflectivity. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In total there seem to be 5 different major factors in how much energy is absorbed by the earth from the sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is what is the relative importance of each of these factors? Is there a set of equations or measurements that describe the total energy received by the sun in terms of these 5 different factors?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastEditorUserId="6298" LastEditDate="2017-06-09T06:10:27.700" LastActivityDate="2017-06-09T06:10:27.700" Title="Why is the part of the earth tilted towards the sun warmer? Which factors matter more?" Tags="|sun|insolation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10291" PostTypeId="1" AcceptedAnswerId="10296" CreationDate="2017-05-03T18:27:50.953" Score="2" ViewCount="92" Body="&lt;p&gt;The Great Britain island and the Italy peninsula look somewhat aligned on the map, like continuations of each other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are they part of the same large scale geological feature? &lt;/p&gt;&#xA;" OwnerUserId="841" LastActivityDate="2017-05-04T03:41:04.397" Title="Are Great Britain and Italy parts of the same geological feature?" Tags="|geology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10292" PostTypeId="1" CreationDate="2017-05-03T22:17:10.643" Score="3" ViewCount="359" Body="&lt;p&gt;Thinking about all the new technologies and techniques that are available to archaeologists now compared to even 50 years ago, it occurred to me that there might be considerable benefit to leaving parts of a site untouched so that future archaeologists can use what you discover, plus new T&amp;amp;T to discover even more. This is the flip side of contaminating samples and disturbing sites, in a way, but it's as much an extension of the &quot;dig, think, then think some more before digging&quot; approach.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Against that I can see how &quot;publish or perish&quot; and similar pressures create incentives to grab as much as possible as quickly as possible. Not everyone can afford the time and money to focus years on the first thing they find on a site.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do archaeologists deliberately leave things untouched for later?&lt;/p&gt;&#xA;" OwnerUserId="8079" LastActivityDate="2017-05-04T00:56:22.100" Title="Do archaeologists deliberately leave parts of sites untouched so that someone can come back later?" Tags="|archaeology|research|" AnswerCount="1" CommentCount="2" ClosedDate="2017-05-04T09:36:58.117" ContentLicense="CC BY-SA 3.0" />
  <row Id="10293" PostTypeId="1" AcceptedAnswerId="10298" CreationDate="2017-05-03T23:44:04.500" Score="2" ViewCount="129" Body="&lt;p&gt;I'm in doubt of some values for future scenarios of climate change that were downloaded from &lt;a href=&quot;http://www.worldclim.org/version2&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.worldclim.org/version2&lt;/a&gt;. For example, the NCAR circulation model for &lt;code&gt;bio_5&lt;/code&gt; variable at optimistic scenario (Max Temperature of Warmest Month) to 2050 is 335.33. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other similar calculations with other scenarios, circulation models and another future year, returns values ranging from 55 to 103 for the max temperature of warmest month. This appears wrong. Am I reading the data correctly?&lt;/p&gt;&#xA;" OwnerUserId="8080" LastEditorUserId="8080" LastEditDate="2017-05-12T13:51:42.580" LastActivityDate="2017-05-12T13:51:42.580" Title="Why do values stored in data files, such as climate model output, appear to be high?" Tags="|climate-change|climate-models|data-formats|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="10294" PostTypeId="2" ParentId="10292" CreationDate="2017-05-04T00:56:22.100" Score="4" Body="&lt;p&gt;Yes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From this article in &lt;a href=&quot;https://www.nationalgeographic.org/encyclopedia/archaeology/&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Geographic&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The last step before digging is to divide the site into a grid to keep&#xA;  track of the location of each find. Then archaeologists choose sample&#xA;  squares from the grid to dig. This allows the archaeological team to&#xA;  form a complete study of the area. They also leave some plots on the&#xA;  grid untouched. &lt;strong&gt;&lt;em&gt;Archaeologists like to preserve portions of their dig&#xA;  sites for future scientists to study—scientists who may have better&#xA;  tools and techniques than are available today&lt;/em&gt;&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(emphasis mine)&lt;/p&gt;&#xA;" OwnerUserId="6057" LastActivityDate="2017-05-04T00:56:22.100" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10295" PostTypeId="2" ParentId="10265" CreationDate="2017-05-04T02:14:46.560" Score="1" Body="&lt;p&gt;Ok, I am answering to myself:&#xA;here are the papers, everything is in there&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/nature/journal/v423/n6942/full/nature01690.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/nature/journal/v423/n6942/full/nature01690.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/ngeo/journal/v3/n2/full/ngeo729.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/ngeo/journal/v3/n2/full/ngeo729.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8025" LastActivityDate="2017-05-04T02:14:46.560" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10296" PostTypeId="2" ParentId="10291" CreationDate="2017-05-04T03:41:04.397" Score="6" Body="&lt;h1&gt;No&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Great Britain doesn't necessarily have a unitary geological origin, but the mountains on it (such as there are mountains) are well worn left-overs from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Caledonian_orogeny&quot; rel=&quot;noreferrer&quot;&gt;Caledonian orogeny&lt;/a&gt; of 400 million+ years ago. These were thrust up before the tetrapods even took to land as part of the plate collision that formed the northern half of Pangaea. This is the same orogeny that made the Appalachians in the US and contributed to the mountains of Scandanavia, as well. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Apennine_Mountains#Geology&quot; rel=&quot;noreferrer&quot;&gt;Appenines&lt;/a&gt; are a result of the much more recent &lt;a href=&quot;https://en.wikipedia.org/wiki/Alpine_orogeny&quot; rel=&quot;noreferrer&quot;&gt;Alpine orogeny&lt;/a&gt;. Caused by the collision of Africa into Eurasia over the last 60 million years or so, this orogeny built mountains from Spain and Morocco to the Zagros and Alborz in Iran.&lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2017-05-04T03:41:04.397" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10297" PostTypeId="1" CreationDate="2017-05-04T10:35:02.243" Score="3" ViewCount="73" Body="&lt;p&gt;I'm doing an assignment where I'm comparing the two mentioned earthquakes, and trying to figure out which factors played a role in the amount of casualties. In the 1998 earthquake there were only three casualties, but in the 2016 earthquake there were nearly 700 casualties. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The population density in 2016 was a lot higher than it was in 1998. I found out that the 1998 earthquake was both deeper and weaker, still I find it strange that only three people died. The 2016 earthquake also occured at about 19:00, where as the 1998 earthquake occured at about 14:00. I'm thinking this plays a role as well, since more people are probably in their houses or asleep at 19:00. The 2016 earthquake also had a lot more aftershocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any other factors you can think of which explains why there were so many more casualties in the 2016 earthquake?&lt;/p&gt;&#xA;" OwnerUserId="8084" LastEditorUserId="5510" LastEditDate="2017-05-04T20:03:23.560" LastActivityDate="2017-05-14T12:20:32.893" Title="Comparing the 4th of August 1998 earthquake to the 16th of April 2016 earthquake in Ecuador" Tags="|seismology|earthquakes|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10298" PostTypeId="2" ParentId="10293" CreationDate="2017-05-04T13:36:35.880" Score="3" Body="&lt;p&gt;My professor gives the solution, as we can see at the site were the climatic variables came from &lt;a href=&quot;http://www.worldclim.org/formats1&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.worldclim.org/formats1&lt;/a&gt;: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Please note that the temperature data are in °C * 10. This means that a value of 231 represents 23.1 °C. This does lead to some confusion, but it allows for much reduced file sizes which is important as for many downloading large files remains difficult. The unit used for the precipitation data is mm (millimeter).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(Edited in by Gerrit): storing (climate) data with offsets and scale factors to reduce file size is common practice, as scaled integers can easily be less than half the size of floats.  When data are stored in standard formats sch as NetCDF or HDF-5, there is probably a variable attribute documenting this.  When data are stored in a homegrown format, check the documentation carefully for any mention of offsets and scale factors that need to be applied.&lt;/p&gt;&#xA;" OwnerUserId="8080" LastEditorUserId="6" LastEditDate="2017-05-05T11:27:29.440" LastActivityDate="2017-05-05T11:27:29.440" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10300" PostTypeId="2" ParentId="10289" CreationDate="2017-05-04T15:39:30.490" Score="4" Body="&lt;p&gt;First look at the article, is cites no sources and is not written by an an expert. It is written without peer review and does not seem to understand how to measure nutritional content (brix is only a measure of sugar not minerals) or what controlled conditions are. No methodology for collection, type of hydroponics, sample size, or anything else is given, this is important becasue many many thing unrelated to the farming method can effect Brix. So you can safely ignore the unscientific claim of the article and go with &lt;a href=&quot;http://hortsci.ashspublications.org/content/33/2/255.short&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;scientific&lt;/strong&gt;&lt;/a&gt; ones, which show no difference when tested. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;First always look at the source of a claim and when in doubt search google scholar first. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is clearly editorial click bait. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2017-05-05T04:53:09.960" LastActivityDate="2017-05-05T04:53:09.960" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10301" PostTypeId="2" ParentId="7080" CreationDate="2017-05-04T16:36:16.110" Score="0" Body="&lt;p&gt;Not all lava is black, the mineral content and cooling speed of the lava has an effect. Cooled lava can have a variety of colors including stark white pumice. &lt;a href=&quot;https://hvo.wr.usgs.gov/volcanowatch/archive/2000/00_10_19.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://hvo.wr.usgs.gov/volcanowatch/archive/2000/00_10_19.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2017-05-04T16:36:16.110" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10303" PostTypeId="1" AcceptedAnswerId="10304" CreationDate="2017-05-04T18:31:22.470" Score="7" ViewCount="344" Body="&lt;p&gt;Here is a screenshot of coseismic interferometry measurements of the 2015 Nepal earthquake. What does it mean?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The star is the epicenter of the earthquake. The screenshot was taken from &lt;a href=&quot;https://unosat.maps.arcgis.com/apps/webappviewer/index.html?id=b9f9da798f364cd6a6e68fc20f5475eb&quot; rel=&quot;noreferrer&quot;&gt;the UNOSAT live crisis map&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XIp8M.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XIp8M.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bJbp6.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bJbp6.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8088" LastEditorUserId="543" LastEditDate="2017-05-05T02:06:35.047" LastActivityDate="2017-05-14T12:17:06.287" Title="How to interpret seismic interferometry data?" Tags="|seismology|earthquakes|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10304" PostTypeId="2" ParentId="10303" CreationDate="2017-05-05T03:25:48.793" Score="6" Body="&lt;p&gt;It is a differential InSAR image that shows wrapped phase in radians which is a measure of the change in range (or distance) between the ground surface and a (more or less) fixed point in space from which the radar images were acquired (keep in mind that two SAR images are required to create an interferogram). To get the actual range change you have to unwrap the interferogram.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can think of the fringes as contour lines. Areas where spacing between the fringes is tight, represent areas with high deformation, e.g., near the fault. The wavelength of the radar determines the fringe spacing. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A better looking interferogram for the Nepal earthquake is at &lt;a href=&quot;http://topex.ucsd.edu/nepal/&quot; rel=&quot;noreferrer&quot;&gt;http://topex.ucsd.edu/nepal/&lt;/a&gt; (made using SAR data acquired by the L-band ALOS-2 satellite operated by the Japanese Space Agency, JAXA).&lt;/p&gt;&#xA;" OwnerUserId="1275" LastActivityDate="2017-05-05T03:25:48.793" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10305" PostTypeId="2" ParentId="10282" CreationDate="2017-05-05T11:51:17.590" Score="0" Body="&lt;p&gt;When looking at its role in planetary temperature, it is not important. Use the s-b equation for mean temperature of the atmosphere, -18C(255K), and the surface temperature, then you see what the effect the air(it doesn´t matter what gases it holds) has on surface temperatures. Emissivity is not really relevant, as emission is dependent on temperature only. Absorption does not cause emission, temperature does. Many people seem to think that emissivity, especially in the case of co2, is something that makes it more possible for co2 to be a warming agent. Not the case. Mean temperature of the atmosphere is -18C, and mean emission from co2 is according to that. Heat transfer equation show how co2 does not add any heat, it is an extra heat sink on the way to the ultimate heat sink in space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just use Stefan-Boltzmann equation and temperature. Solar heat is absorbed according to the geometric difference between the blackbody and earth, two volumes with shells. $TSI/(4/3^2)$. And since only half the surface area is irradiated, $(1/2*TSI)/(4/3^2)=383W/m^2$ or 286.7 Kelvin. The effective temperature is found by heat transfer to the surface and inverse square law, $1/4*(TSI-((1/2*TSI)/(4/3^2)))=244W/m^2$, or 256 Kelvin. Tropopause temperature, $((1/2*TSI)/(4/3^2))-(1/4*(TSI-((1/2*TSI)/(4/3^2)))=138W/m^2$ or 222 Kelvin.&#xA;As you can see, heat dominates everything, and just modifying the blackbody to observed differences, absorption in depth of a volume + irradiation of only half the surface, gives an accurate distribution of temperature. It clearly shows why it is a big problem that the greenhouse effect use averaged solar heat over the whole surface. And also, albedo is not a concept that should be used for heat. I think it came from optics in the beginning, and it shouldn´t be used for temperature. Emitted heat depends on temperature only.&lt;/p&gt;&#xA;" OwnerUserId="8095" LastEditorUserId="8095" LastEditDate="2017-05-05T21:39:39.640" LastActivityDate="2017-05-05T21:39:39.640" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10307" PostTypeId="1" AcceptedAnswerId="14890" CreationDate="2017-05-05T13:25:04.147" Score="18" ViewCount="4507" Body="&lt;p&gt;I was curious about how the Earth's overall air pressure has varied over time, and tried to take a look around the internet. However, Google pops up a lot of sites with questionable science proposing that the air pressure was much higher in the past. The more outrageous claims (such as those by David Esker) are dealt with on &lt;a href=&quot;https://skeptics.stackexchange.com/questions/19073/what-was-the-density-of-prehistoric-earth-atmosphere-dinosaurs-buoyancy-theory&quot;&gt;Skeptics.SE&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, there are more reasonable claims that air pressure was perhaps 4 or 5 times higher in the Mesozoic, thus allowing pterosaurs to fly more effectively, etc. The websites making such claims do heavily set off my pseudoscience alarms, but then &lt;a href=&quot;http://pubs.acs.org/subscribe/archive/ci/30/i12/html/12learn.html&quot; rel=&quot;noreferrer&quot;&gt;some are published&lt;/a&gt; by the American Chemical Society by reputable sounding scientists with references to papers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is evidence that in the far distant past, air pressures &lt;a href=&quot;http://www.nature.com/ngeo/journal/v9/n6/full/ngeo2713.html&quot; rel=&quot;noreferrer&quot;&gt;were lower&lt;/a&gt; than they are currently. But after the changes to the atmosphere wrought by photosynthetic life, is there any evidence supporting the various theories of higher air pressures?&lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="11908" LastEditDate="2019-04-06T20:07:53.570" LastActivityDate="2020-02-27T01:18:34.030" Title="Is there any evidence for higher air pressures in the geological past?" Tags="|geology|atmosphere|climate-change|planetary-science|paleoclimatology|" AnswerCount="3" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="10308" PostTypeId="2" ParentId="10138" CreationDate="2017-05-05T17:40:48.780" Score="-5" Body="&lt;p&gt;First we need to see if your question is based on facts. If the only energy in the climate system comes from the sun, what things can increase the energy in the system, other than the sun? The answer is: nothing.&#xA;To increase temperature you need to increase the intensity of emitted heat where the temperature increase. Since the only source of energy is the sun, how could we increase the intensity anywhere, if not the intensity of solar irradiation is increased?&#xA;This is a surprising mistake done by the entire climate science. The claim is that increasing the amount of a potent &lt;strong&gt;heat absorber&lt;/strong&gt; would increase the intensity of emitted heat from the surface. If you add a &lt;strong&gt;heat absorber&lt;/strong&gt; that absorbs heat from a body, it cannot cause warming. Often it is claimed to retain, or delay heat loss. But that cannot be true according to thermal physics. Preventing heat loss is exactly what we do by insulating the boundary of the system we want to stay warm. Thermal insulation is a logic simple thing, you can read about it here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Thermal_insulation&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Thermal_insulation&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Thermal insulation provides a region of insulation in which thermal conduction is reduced or thermal radiation is reflected rather than absorbed by the lower-temperature body.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, it is without doubt very clearly stated, that preventing heat loss, or retaining heat, is done in the exact opposite way to what the theory of global warming claims. Absorption is what you want to avoid to prevent heat loss. There is a lot of things in the warming science-camp that indicate a lack of physics education in their field of science. Actually, every single argument in the greenhouse theory is a head-on violation of known, proven 100% consensus physics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, first of all, according to proven physics, it is highly unlikely that there is a warming climate at all. Secondly, the ocean cannot warm, if the amount of heat from the sun doesn´t increase. And we know that it doesn´t.&lt;/p&gt;&#xA;" OwnerUserId="8095" LastActivityDate="2017-05-05T17:40:48.780" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10309" PostTypeId="2" ParentId="9669" CreationDate="2017-05-05T18:25:51.823" Score="-4" Body="&lt;p&gt;All radiation is thermal. I really can´t understand why anyone makes a difference between different parts of the spectrum. The &quot;visual&quot; part of radiation is entirely relative to human eye-sight. The definition of visual is exactly that, the radiation which the receptors in our eyes respond to. The concept &quot;albedo&quot; is also something entirely relative to human eye-sight, and it should be questioned if it is correct to use it for a planet in regards to temperature at all. For example, snow is like a perfect blackbody absorber outside the visual spectrum, but in the visual it is reflective. And solar radiation is 51% IR(thermal), so what use do we have of &quot;albedo&quot; when we calculate temperature?&#xA; &quot;Thermal&quot; radiation is entirely based on the fact that human eyes doesn´t respond to those wavelengths, and the rest of the longwave radiation parts of the spectrum is called non-thermal mostly because humans can´t sense it at all. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Solar radiation&quot; cover the spectral parts where we say that the gases in question is opaque, although wavelengths are mostly in the higher frequency part. So the &quot;transparent&quot; parts apply to both solar and thermal, with your definitions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fact is, all radiation is thermal, intensity and wavelengths depends on the temperature of the emitter, only. Any part of the spectrum has an intensity according to the temperature of the emitter, spectral resolution and peak intensity of emission is also caused by the temperature of the emitter. The entire concept of radiation in the universe is an exclusive relationship where emission depends on temperature alone. If we know this, which we do, then all radiation is thermal. And nothing on earth, no matter what gases are involved, should interfere with that relationship, because it would be a violation of 100% consensus physics. Emission is dependent on temperature alone, absorption is due to temperature only. Spectral resolution is quantum physics, and we don´t use that for temperature. Now, if you want to discuss spectral character of something, that is fine. But if we are talking about temperature, of the atmosphere or earth surface, transparency should not be involved.&lt;/p&gt;&#xA;" OwnerUserId="8095" LastActivityDate="2017-05-05T18:25:51.823" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10310" PostTypeId="2" ParentId="10128" CreationDate="2017-05-05T19:03:23.933" Score="5" Body="&lt;p&gt;The thing is, we don´t have any instruments(to my knowledge) to measure the intensity of that radiation. But, we measure the intensity of atmospheric emission from space with satellites, which is seen as the &quot;effective temperature&quot;. Logically this is the same as the net radiation downwards. And heat transfer then confirms that no net radiation arrives at the surface. Which is equal to &quot;no radiation at all&quot;. Because &quot;net&quot; radiation is the only radiation that can heat anything.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are lots of people claiming that measurements done with IR sensors and pyrgeometers confirm backradiation. This is not true and it is based on a misunderstanding of the function of the device, as well as misapplication of the stefan-boltzmann equation. Both IR-thermometers and pyrgeometers use the s-b equation  in combination with a thermocouple or thermopile(pyrgeometer). They are both a kind of more advanced and more sensitive thermometers. The thermopile consist of a sensor measuring a gradient across itself indirectly by changes in resistance acting on a current through the thermopile. So, by determining the gradient in the thermopile, it can sense the amount of heat transferred to the surroundings using the s-b equation. When someone claims measurements show &quot;back-radiation&quot;, they refer to measurements done with these devices. As most interested people understand, a measurement of heat transfer away &lt;strong&gt;from&lt;/strong&gt; the device, cannot show incoming radiation from a colder atmosphere. If you measure something hotter than the temperature of the thermopile, sure, then you have high accuracy. But a measurement of &quot;back-radiation&quot; from the atmosphere is per definition a measurement of something colder than the device. Because the atmosphere is almost always colder(exception is inversion, but that is not relevant). So any measurement of backradiation made from the surface, is a measurement of nothing. It is simply what the device &lt;strong&gt;doesn´t&lt;/strong&gt; measure coming from the atmosphere. This is what I mean with &quot;misapplication&quot; of the s-b equation. It can not, and should not, be used that way. That is, to add flux densities that are not calculated as &quot;net&quot; transfer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In regards to your suggested experiment. Unless the gas is hotter than the instruments(if using IR-instruments), you will measure a heat sink, not any backradiation. And, yes, that is what greenhouse gases really are. Heat sinks. The earth emit its heat to the ultimate bottomless heat sink in space, the only observed infinity, and greenhouse gases are added heat sinks along the highway for heat, that leads to 3 Kelvin space.&lt;/p&gt;&#xA;" OwnerUserId="8095" LastActivityDate="2017-05-05T19:03:23.933" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10311" PostTypeId="2" ParentId="1060" CreationDate="2017-05-05T19:16:50.940" Score="-4" Body="&lt;p&gt;Add a heat sink. A heat sink is an absorber of heat. So add co2, or dry ice as we usually call it. It is an excellent heat sink.&lt;/p&gt;&#xA;" OwnerUserId="8095" LastActivityDate="2017-05-05T19:16:50.940" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10312" PostTypeId="1" CreationDate="2017-05-05T19:19:56.493" Score="1" ViewCount="53" Body="&lt;p&gt;The earth is made up of 70% hydrosphere and 30% lithosphere.The space of lithosphere is continually used and it seems there is a threat to a balance ecosystem.Describe how the hydrosphere can be make good use of to reduce the loads on the lithosphere &lt;/p&gt;&#xA;" OwnerUserId="8098" LastEditorUserId="725" LastEditDate="2017-05-05T22:46:00.773" LastActivityDate="2017-05-05T22:46:00.773" Title="How can the hydrosphere be properly used to reduce the load on the lithosphere" Tags="|homework|atmospheric-chemistry|" AnswerCount="0" CommentCount="2" ClosedDate="2017-05-23T07:34:27.990" ContentLicense="CC BY-SA 3.0" />
  <row Id="10314" PostTypeId="2" ParentId="825" CreationDate="2017-05-05T20:22:58.513" Score="-2" Body="&lt;p&gt;Sunlight is 393 Kelvin. The earth is irradiated at half the surface area that emits the radiation. And the radiation is absorbed in a spherical volume. So: &#xA;$((σ393^4/(4/3))/2=510W/m^2$ or 308 Kelvin(32 degrees celsius). &lt;/p&gt;&#xA;" OwnerUserId="8095" LastEditorUserId="8095" LastEditDate="2017-05-05T20:28:02.923" LastActivityDate="2017-05-05T20:28:02.923" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10315" PostTypeId="1" AcceptedAnswerId="10316" CreationDate="2017-05-05T21:10:14.333" Score="2" ViewCount="131" Body="&lt;p&gt;I had this question in my previous exam, it says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Deterioration of vegetation resulted by overgrazing results in......&lt;/p&gt;&#xA;&lt;p&gt;1.desert encroachment.&lt;/p&gt;&#xA;&lt;p&gt;2.change in climate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I had to choose 1 or 2 and I chose 2, why? Because my textbook says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Overgrazing results in deterioration of natural flora, which is always accompanied by deterioration of soil and local climate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;But my answer was wrong, and I was confused which one to choose because both of them seem as correct answers. What I understand from my  text book is that deterioration of vegetation has a direct effect i.e. change in climate and an indirect effect i.e. desert encroachment. So, why was my answer wrong?&lt;/p&gt;&#xA;" OwnerUserId="6908" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-05-06T03:06:24.803" Title="Result of deterioration of vegetation" Tags="|climate|homework|ecology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10316" PostTypeId="2" ParentId="10315" CreationDate="2017-05-06T03:06:24.803" Score="1" Body="&lt;p&gt;I think the reason you were marked wrong is because your text book is using the term &quot;climate&quot; loosely.  The deterioration of vegetation will result in desert encroachment ... which in turn can cause a change in local climate.  After all, if you create more desert, you have changed the local climate, right?  However, it takes many years to define a climate period, whereas desert encroachment can happen year to year.  So, eventually the local climate can change... but not if the desert encroachment reverses for some reason.  It's a very fine line, but answer #1 will most certainly occur while #2 may occur afterward if #1 is sustained.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-05-06T03:06:24.803" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10317" PostTypeId="1" CreationDate="2017-05-06T17:03:14.780" Score="0" ViewCount="259" Body="&lt;p&gt;I have made a modified blackbody model that predict earth temperature distribution with high accuracy. It doesn´t include mass or gases. It is based on the initial thought that all energy above surface is solar heat, and heat transfer must apply to the system. Just some simple modification to the perfect blackbody surprisingly enough gave very accurate results. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I answered a question with these equations, but a moderator deleted it for unknown reasons. It is only numbers, and no speculation, so I really can´t understand why. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The greenhouse effect uses The Stefan-Boltzmann equation to add fluxes, stacking them, and that is not allowed in thermal physics. It is a balance equation and should only be used for &quot;net&quot; transfer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I show why it is wrong to use an average value of solar irradiation over the whole surface area, it is because intensity is instantaneous. You cannot use average, because that means that the sun would only be ~5C. Or -18C depending on what solar average you use. Solar heat is about 105Celsius at TOA, that makes a big difference. I show how surface temperature and atmosphere temperature distribution is connected to the solar constant all the way. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is not shown here, but the model also show direct and total irradiation at zenith, with accuracy. Anyway, since it was deleted without explanation, I get the feeling of censorship, since it falsifies the greenhouse effect. Now I ask you. What is wrong with it?: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I use Stefan-Boltzmann equation and temperature. Solar heat is absorbed according to the geometric difference between the blackbody and earth, two volumes with shells.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$TSI/(4/3^2)$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And since only half the surface area is irradiated, &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$(1/2∗TSI)/(4/3^2)=383W/m^2$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;or 286.7 Kelvin. The effective temperature is found by heat transfer to the surface and inverse square law,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$1/4∗(TSI−((1/2∗TSI)/(4/3^2)))=244W/m^2$, or 256 Kelvin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tropopause temperature:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$((1/2∗TSI)/(4/3^2))−(1/4∗(TSI−((1/2∗TSI)/(4/3^2)))=138W/m^2$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;or 222 Kelvin. As you can see, heat dominates everything, and just modifying the blackbody to observed differences, absorption in depth of a volume + irradiation of only half the surface, gives a accurate distribution of temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The numbers are, from my POV, unquestionable. Such a good fit falsifies the greenhouse immediately, especially since no experiments show the effect where cold gas can increase the intensity of the heat source heating it, which the theory claims. So, what are your opinions?&lt;/p&gt;&#xA;" OwnerUserId="8095" LastEditorUserId="8095" LastEditDate="2017-05-06T18:41:05.653" LastActivityDate="2017-05-06T18:41:05.653" Title="Modified blackbody model of earth. What is wrong with it?" Tags="|climate|temperature|radiative-transfer|greenhouse-gases|" AnswerCount="1" CommentCount="3" ClosedDate="2017-05-07T21:41:01.877" ContentLicense="CC BY-SA 3.0" />
  <row Id="10318" PostTypeId="2" ParentId="10317" CreationDate="2017-05-06T17:57:19.487" Score="2" Body="&lt;p&gt;The premise that the Stefan-Boltzmann equation is used for greenhouse gases is wrong. The Stefan-Boltzmann equation is used for irradiance output, not energy input. The ground warms the atmosphere, and the atmosphere releases energy into space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suggest looking at the one-dimensional energy balance model. See &lt;a href=&quot;http://kurs.uib.no/acdc/filer/219.BYQINh.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://kurs.uib.no/acdc/filer/219.BYQINh.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-05-06T17:57:19.487" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10319" PostTypeId="2" ParentId="9669" CreationDate="2017-05-06T18:16:26.407" Score="0" Body="&lt;p&gt;Not to the best of the my knowledge. Such a thing is called dark matter, which is almost undetectable. None of it exists in our atmosphere, at least that we know of.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2017-05-06T20:13:16.770" LastActivityDate="2017-05-06T20:13:16.770" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10320" PostTypeId="2" ParentId="7302" CreationDate="2017-05-06T21:44:27.570" Score="1" Body="&lt;p&gt;It seems you have downloaded a native format file.  This is not an HDF readable format.  If you see the first link you've given, under distribution it notes there are several formats you can download:  Native, Image (J2KBW, JPEGBW, PNGBW, TIFFBW), BUFR, or netCDF.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to use HDF libraries to read the file, you will need to download the netCDF formatted files.  netCDF is compliant with HDF5 libraries.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-05-06T21:44:27.570" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10321" PostTypeId="1" CreationDate="2017-05-07T02:21:39.123" Score="3" ViewCount="504" Body="&lt;p&gt;What purpose is served by taking sea level as the reference point for finding the height of any point on Earth when we all know that measuring the sea level is a very complex task and it differs from place to place and also keeps on changing? Why can't we just take Earth's centre as the reference point for finding the height of any location?&lt;/p&gt;&#xA;" OwnerUserId="8102" LastEditorUserId="8102" LastEditDate="2017-05-07T02:30:21.407" LastActivityDate="2017-05-07T18:13:32.747" Title="Elevation of a point on Earth" Tags="|geology|cartography|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10322" PostTypeId="2" ParentId="446" CreationDate="2017-05-07T03:41:18.903" Score="3" Body="&lt;p&gt;The question asked is &quot;why do snowflakes form into hexagonal structures&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I see snowflakes as following the framework of a flattened cuboctahedron.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pIKlm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pIKlm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oqTkb.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oqTkb.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ICru9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ICru9.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cLysg.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cLysg.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="809" LastActivityDate="2017-05-07T03:41:18.903" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10323" PostTypeId="2" ParentId="10321" CreationDate="2017-05-07T05:27:46.727" Score="6" Body="&lt;p&gt;There are many reasons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, measuring from sea level is traditional. It started before we had an accurate way of measuring distance from the center of the Earth, and probably before most people knew it was (approximately) a sphere.  But anyone living by the shore could determine sea level to within a few feet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another reason is that measuring from sea level tells you useful things like pressure altitude, which are important if you're a pilot or mountain climber.  The polar and equatorial radii differ by about 14 miles (21 km), so depending on your location, a distance of say 6,365 km from the center could be deep underground or halfway to the stratosphere.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastEditorUserId="1401" LastEditDate="2017-05-07T18:13:32.747" LastActivityDate="2017-05-07T18:13:32.747" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10324" PostTypeId="2" ParentId="10321" CreationDate="2017-05-07T16:41:18.773" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Why can't we just take Earth's centre as the reference point for finding the height of any location?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;While there are many uses for Earth-centered, Earth-fixed coordinates, they're not particularly useful or meaningful in most human-centric endeavors, which happen on or near the surface of the Earth. Consider two points on the surface of the Earth, one at a distance of 6377.12 km from the center of the Earth, the other at 6359.59 km. At which location will you have to worry about altitude sickness? The answer is the one that is 17.53 km closer to the center of the Earth. The first location is Lake Asal in Africa, which is 155 meters below mean sea level. The second location is the Amundsen-Scott South Pole Station, which is 2835 meters above mean sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because those ECEF coordinates are not particularly useful or meaningful, the first thing a GPS receiver does after computing position in ECEF coordinates is to convert that position to latitude, longitude, and elevation above a reference ellipsoid. There's an issue with this, which is the use of a reference ellipsoid. Some places at sea level have an elevation of 85 meters above the reference ellipsoid, others as much as 107 meters below the reference ellipsoid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While there certainly are challenges in the concept of mean sea level, it remains extremely useful. It tells us, for example, which parts of New Orleans are subject to coastal flooding, which parts of Fargo are subject to springtime flooding, and which parts of Colorado are subject to altitude sickness.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-05-07T16:41:18.773" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10325" PostTypeId="1" AcceptedAnswerId="10327" CreationDate="2017-05-07T19:00:34.633" Score="3" ViewCount="353" Body="&lt;p&gt;I can find information about the basin as a water-source, along with photos of the ground over its 1,700,000 square km surface. But have divers ever entered this space, or tunnels been dug for cameras, have photos ever been taken of it from under its waters?&lt;/p&gt;&#xA;" OwnerUserId="8104" LastEditorUserId="2536" LastEditDate="2017-05-08T01:47:20.767" LastActivityDate="2017-05-08T01:54:18.773" Title="Has anyone driven under, or received camera footage from, the Great Artesian Basin in Australia?" Tags="|geology|groundwater|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10327" PostTypeId="2" ParentId="10325" CreationDate="2017-05-08T01:45:54.257" Score="7" Body="&lt;p&gt;Groundwater is stored in the porosity of rocks, that is space between &lt;a href=&quot;https://en.wikipedia.org/wiki/Clastic_rock&quot; rel=&quot;noreferrer&quot;&gt;clasts&lt;/a&gt; or cracks. Larger cavities, e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Karst&quot; rel=&quot;noreferrer&quot;&gt;karsts&lt;/a&gt;, is usually only a minor contribution to ground water reservoirs and are only common in limestone. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Great Artesian Basin aquifer is made up of Mesozoic sandstone. It is covered by impermeable rocks that allow pressure to build up within the aquifer so that as rainwater enters at high elevation it will keep the hydrostatic pressure, even when the topography is lower. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only way to see the rocks at great depths is by drilling and, if the budget allows, also keep &lt;a href=&quot;https://en.wikipedia.org/wiki/Core_sample&quot; rel=&quot;noreferrer&quot;&gt;core sample&lt;/a&gt; to be able to analyze it. Important information also comes from &lt;a href=&quot;https://en.wikipedia.org/wiki/Well_logging&quot; rel=&quot;noreferrer&quot;&gt;borehole logging&lt;/a&gt; when geophysical instruments are lowered into the borehole to measure e.g. porosity and density of the rocks. One can also see the continuation of the formation on the surface and study the rocks to understand how they look at great depths. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.environment.gov.au/system/files/resources/6405b0fb-1956-4790-9ca4-b138ed810717/files/great-artesian-basin-managing.pdf&quot; rel=&quot;noreferrer&quot;&gt;This informative document&lt;/a&gt; explains some of the features of The Great Artesian Basin rather well, but don't be mislead to think about the aquifers as caves, it is only water soaked rocks. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-05-08T01:54:18.773" LastActivityDate="2017-05-08T01:54:18.773" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10328" PostTypeId="2" ParentId="8211" CreationDate="2017-05-08T01:57:38.493" Score="2" Body="&lt;p&gt;&lt;strong&gt;Yes&lt;/strong&gt;&#xA; We have them all the time they are called &lt;a href=&quot;https://en.wikipedia.org/wiki/Sunshower&quot; rel=&quot;nofollow noreferrer&quot;&gt;sun showers&lt;/a&gt;&#xA; Wind can push rain miles from the clouds that it falls from. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2017-05-08T01:57:38.493" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10329" PostTypeId="2" ParentId="2122" CreationDate="2017-05-08T04:58:04.257" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Alternatively, are there any mountains on Earth where (for whatever&#xA;  reason) erosion hasn't played a big role in shaping them so far, and&#xA;  which therefore look similar to the uneroded mountains one would find&#xA;  on an airless world?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The entire Tibetan plateau is a mountain range unexposed to erosion. It's a lifted landmass that just needs a little rain and snow to get the ball rolling. Same goes for the Colorado plateau, although in a few small sections, moisture has carved a few canyons and valleys that may end up as mountains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is essentially no difference, visually, between a flat plain and an uneroded mountain range.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-05-08T04:58:04.257" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10330" PostTypeId="2" ParentId="10307" CreationDate="2017-05-08T05:25:10.007" Score="4" Body="&lt;p&gt;All manner of isotopic analyses confirms that the chemical composition of the earth's atmosphere has fluctuated wildly in the past. Besides the Archean hypoxic atmospheres of 2.5 billion years ago, the late Paleozoic saw oxygen concentrations that were much higher than they are today allowing a wide variety of giant insects to thrive (simple diffusion is a large part of insect respiration). Some believe that in addition to much higher oxygen levels, a much higher air density (pressure) may have accelerated the development of flight in these insects:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://brendans-island.com/blogsource/20140826ff-Documents/JExpBiol-1998-Dudley-1043-50.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;ATMOSPHERIC OXYGEN, GIANT PALEOZOIC INSECTS AND THE EVOLUTION OF&#xA;AERIAL LOCOMOTOR PERFORMANCE&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By the way, the internets are full of people who don't understand the difference between &quot;high oxygen partial pressure&quot; and &quot;high atmospheric pressure&quot;.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-05-08T05:25:10.007" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10331" PostTypeId="1" AcceptedAnswerId="10333" CreationDate="2017-05-08T08:27:59.240" Score="8" ViewCount="2266" Body="&lt;p&gt;I have read about some of the geologic processes that are related to the formation of fjords. Is the presence of sills in fjords related to the deposition of glacial moraine?&lt;/p&gt;&#xA;" OwnerUserId="7964" LastEditorUserId="2536" LastEditDate="2017-05-08T10:06:29.153" LastActivityDate="2017-05-08T13:56:02.313" Title="Why do fjords have sills?" Tags="|geology|glaciology|bathymetry|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10332" PostTypeId="1" CreationDate="2017-05-08T09:28:26.513" Score="8" ViewCount="1993" Body="&lt;p&gt;In my house, we drink the groundwater that we get from our well. It is 40 meters deep. The question is, how old is the water that we drink today? Is it from the rain 100 years ago? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another issue is, today much pesticide is used. Someday they will diffuse down to the underground 40 meter. How long will it take?   &lt;/p&gt;&#xA;" OwnerUserId="7206" LastEditorUserId="12057" LastEditDate="2018-03-10T18:04:36.263" LastActivityDate="2018-03-10T18:10:52.720" Title="How old is Earth's groundwater?" Tags="|water|groundwater|environmental-protection|age|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10333" PostTypeId="2" ParentId="10331" CreationDate="2017-05-08T10:03:54.323" Score="9" Body="&lt;p&gt;Fjords are formed as &lt;a href=&quot;https://en.wikipedia.org/wiki/U-shaped_valley&quot; rel=&quot;noreferrer&quot;&gt;U-shaped valleys&lt;/a&gt; by the extreme erosion of glaciers. The glacier erodes large quantities of material that is transported by the ice. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The glacier can erode &lt;a href=&quot;https://en.wikipedia.org/wiki/Overdeepening&quot; rel=&quot;noreferrer&quot;&gt;deep under the sea level&lt;/a&gt; (remember how an iceberg only has 1/10 of its mass &lt;a href=&quot;http://static.diffen.com/uploadz/7/7c/iceberg--1.jpg&quot; rel=&quot;noreferrer&quot;&gt;above the surface&lt;/a&gt;) and if the postglacial rebound is limited, the fjord will remain as an estuary. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the glacier slows down and withdraws, the sediments are dumped at the front of it to form a terminal moraine or &lt;em&gt;sill&lt;/em&gt;. This is particularly pronounced if the front of the glacier had shrunken, growing again before melting due to environmental oscillations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sills are usually deposited at the mouth of the fjord, before the water depth increases. However, the biggest part of the glacial debris is deposited at deeper water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might also have shallow water in front of rias, were the flow slows down and sediments are deposited, but they will rarely form obvious sills as in a fjord. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-05-08T13:56:02.313" LastActivityDate="2017-05-08T13:56:02.313" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10334" PostTypeId="1" CreationDate="2017-05-08T11:51:05.773" Score="5" ViewCount="68" Body="&lt;p&gt;How can I obtain coefficients for Degree-Day Factor method estimating snowmelt rate? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any reference would be appreciated. &lt;/p&gt;&#xA;" OwnerUserId="8109" LastActivityDate="2017-05-08T11:51:05.773" Title="calculation of coefficients for snow melt DDF" Tags="|snow|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10335" PostTypeId="2" ParentId="10332" CreationDate="2017-05-08T13:49:17.343" Score="7" Body="&lt;p&gt;The age of groundwater can vary over a large span. The moment a drop of rain enters the ground it becomes groundwater and when it reaches the groundwater table, the water starts to &lt;a href=&quot;https://en.wikipedia.org/wiki/Groundwater_flow_equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;flow&lt;/a&gt; towards a lower hydrostatic level, usually towards the sea, a river or a lake. If you have a well, you'll pump up water to lower the hydrostatic level near the well, so that local groundwater will flow towards the well instead of the ocean. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The velocity of the flow depends on a &lt;a href=&quot;https://en.wikipedia.org/wiki/Darcy%27s_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;number of parameters&lt;/a&gt;. Naturally, the distance from the recharge area, the hydrostatic pressure, that is the elevation difference over the flow, and finally but not least important, the permeability of the soil and rocks it flows through. If the ground consists of e.g. porous sand, gravel from outwash planes or very fractured rocks the water will flow fast towards a lower level, but if the ground in impermeable, eg. shale or igneous rocks without cracks, the flow will be much slower. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eCiHi.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eCiHi.png&quot; alt=&quot;Creative Commons Attribution-Share Alike 3.0 Unported USGS&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have sandy ground, and shallow groundwater table, the pesticides will reach the groundwater table in very short time (maybe days?), if the &lt;a href=&quot;https://en.wikipedia.org/wiki/Aquifer&quot; rel=&quot;nofollow noreferrer&quot;&gt;aquifer&lt;/a&gt; is covered by clay, it might take millennia. It also depends on the unsaturated zone and the mosture above the groundwater table. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, unfortunately, it's impossible to answer your question(s) without more information. Shallow groundwater is typically from zero to a couple of hundred years old. Some thousand years are not uncommon and for deep aquifer (that have little hydrostatic pressure reason to flow towards an ocean). It can be millions or even &lt;a href=&quot;http://www.livescience.com/32028-oldest-water-found-underground.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;billion&lt;/a&gt; years old.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The age of groundwater can be detected by Carbon-14 decay or by measuring known contamination, eg. CFCs, depending on the age range. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are worried about contamination of you your well, apart from analyse the water, I'd make some sketches of the groundwater flow, e.g. map nearby rivers (river surface = groundwater surface) and the hydrostatic level (well water surface) in your well to find out what direction the water and contamination flow. If the contamination is between you and a river, the best guess would be that the contamination flows away from you, but if you pump up alot of water, the gradient of the groundwater table might change and the contaminations flow toward your well instead of the river. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="11908" LastEditDate="2018-03-10T18:10:52.720" LastActivityDate="2018-03-10T18:10:52.720" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10336" PostTypeId="1" AcceptedAnswerId="10337" CreationDate="2017-05-08T14:07:15.773" Score="8" ViewCount="3392" Body="&lt;p&gt;If I wanted to make an air shield around the earth to contain exactly half the planet's atmosphere (by mass), how far above sea level would I have to build it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's slightly complicated to me because you have to take into consideration the change in pressure as well as the geometric growth of the volume of a sphere as you increase the radius.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="8111" LastActivityDate="2017-05-09T06:08:00.200" Title="How far up do you have to go before most of the atmosphere is below you?" Tags="|meteorology|atmosphere|planetary-science|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10337" PostTypeId="2" ParentId="10336" CreationDate="2017-05-08T15:46:53.527" Score="9" Body="&lt;p&gt;Roughly 5.5 km, although the exact value depends on the weather.  All you need to do is to &lt;a href=&quot;https://en.wikipedia.org/wiki/Vertical_pressure_variation&quot; rel=&quot;noreferrer&quot;&gt;solve the hydrostatic equation&lt;/a&gt; and find the height at which the pressure is 50% of the height at sea level (or perhaps average elevation of Earth surface instead of sea level).  Any answer actually performing the calculation deserves upvotes more than I do ;-)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See, for example, &lt;a href=&quot;http://www.pdas.com/atmthick.html&quot; rel=&quot;noreferrer&quot;&gt;Thickness of Earth's Atmosphere&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Using boundary layer theory as an example, we can define the thickness of the atmosphere to be the altitude that encloses 99 percent of the total mass of the atmosphere. Looking at the chart, we can see that this seems to be about 31 kilometers. The halfway point, where half the mass of the atmosphere is below and half above occurs at 5.5 kilometers. Another interesting fact is that when you are cruising in a modern jet transport at 11 kilometers, you are above 77.5 percent of the atmosphere. The total mass of the atmosphere turns out to be 5.3 zettagrams (5.3 Zg). &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm not entirely sure how the calculations in the linked article are performed, but I recall calculating this as a student and ending up somewhere around 5 km, so it sounds right.  Simple calculations often assume an isothermal atmosphere, which is of course not accurate, but good enough if you don't need to know the answer more precisely than within several hundred metre.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://nova.stanford.edu/projects/mod-x/id-pres.html&quot; rel=&quot;noreferrer&quot;&gt;This page at Stanford reaches the same number.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2017-05-08T15:53:51.000" LastActivityDate="2017-05-08T15:53:51.000" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10338" PostTypeId="2" ParentId="10336" CreationDate="2017-05-08T16:00:16.567" Score="9" Body="&lt;p&gt;It turns out that the answer is a bit simpler than you think. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Atmospheric pressure (neglecting small weather variations) is due to the weight of the column of air above a given point. If we divide the pressure at a given altitude by the pressure at sea level, we get the amount of atmosphere left above us. To find the height at which half the atmosphere is below us, we just need to find the height at which the pressure is half of the sea level pressure, which turns out (from standard atmosphere charts) to be slightly less than 18,000 feet (about 5500 metres).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to work out the expression for the change in pressure with height, that can be done from assuming that air is an ideal gas and using hydrostatic pressure.&lt;/p&gt;&#xA;" OwnerUserId="8112" LastEditorUserId="725" LastEditDate="2017-05-09T06:08:00.200" LastActivityDate="2017-05-09T06:08:00.200" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10341" PostTypeId="1" AcceptedAnswerId="10353" CreationDate="2017-05-08T19:40:54.110" Score="4" ViewCount="152" Body="&lt;p&gt;I have a newbie question...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I always used the &lt;a href=&quot;https://en.wikipedia.org/wiki/International_Standard_Atmosphere#/media/File:Comparison_International_Standard_Atmosphere_space_diving.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;International Standard Atmosphere model&lt;/a&gt; whenever I needed to calculate the temperature in a given altitude.&#xA;It always looked accurate to me...  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, doing some work using &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/model-data/model-datasets/global-forcast-system-gfs&quot; rel=&quot;nofollow noreferrer&quot;&gt;GFS data&lt;/a&gt;, I found something intriguing..&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At a given high altitude (let's say : 150 hpa/44000ft), the temperature I saw in the GFS model was almost always colder than the ISA temperature for that altitude&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This was mostly TRUE for latitudes between -30 and 30º, and the OPPOSITE for abs(latitudes) &gt; 30º.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fyeNC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fyeNC.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, I came with a hypothesis... Want I want to know if it is crazy or not.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The ISA model is an average model. Temperatures in the tropics are lower (for high altitudes) and the temperatures near the poles are higher. The final average is the ISA model.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="8115" LastActivityDate="2017-05-09T22:36:02.423" Title="ISA Model and GFS data" Tags="|meteorology|temperature|weather-forecasting|gfs|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10342" PostTypeId="1" AcceptedAnswerId="10343" CreationDate="2017-05-08T20:39:47.220" Score="3" ViewCount="158" Body="&lt;p&gt;I'm a Brazilian native. Here, the English translation to the most didactic way to express the Amazon seasons are: &quot;rainy season&quot;, and &quot;less rainy season&quot;, because it always rains a lot, but there is a period when there is less. Does anyone know if this is the best way to express this in English scientific language? &lt;/p&gt;&#xA;" OwnerUserId="8080" LastEditorUserId="6298" LastEditDate="2017-05-11T17:37:54.120" LastActivityDate="2017-05-11T17:37:54.120" Title="Are &quot;rainy season&quot; and &quot;less rainy season&quot; good ways to describe Amazon seasons in English scientific language?" Tags="|terminology|seasons|amazon|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10343" PostTypeId="2" ParentId="10342" CreationDate="2017-05-08T21:25:27.093" Score="3" Body="&lt;h1&gt;Dry season&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;While not being very descriptive, 'dry season' is in general use, even for rainforests (&lt;em&gt;Af&lt;/em&gt; Koppen climate, if you will). Example papers using the terminology &lt;a href=&quot;https://scholar.google.com/scholar?hl=en&amp;amp;q=amazon%20dry%20season&amp;amp;btnG=&amp;amp;as_sdt=1%2C47&amp;amp;as_sdtp=&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2017-05-08T21:25:27.093" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10344" PostTypeId="1" CreationDate="2017-05-09T06:28:30.827" Score="5" ViewCount="84" Body="&lt;p&gt;What conditions would cause these windswept clouds at sunset in Michigan? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do these cloud forms have a name?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5awPx.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5awPx.jpg&quot; alt=&quot;Sunset Michigan&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8123" LastEditorUserId="595" LastEditDate="2017-05-09T08:29:13.800" LastActivityDate="2017-05-09T21:02:21.283" Title="How do these cloud forms grow?" Tags="|clouds|wind|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10345" PostTypeId="1" CreationDate="2017-05-09T09:19:09.440" Score="3" ViewCount="501" Body="&lt;p&gt;I was reading a &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2006WR005155/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt; (equation 1 in linked paper) where they used 'linearized Boussinesq' equation to model groundwater in unconfined aquifer.  The linearized Boussinesq equation described in the paper was $$\frac{\partial h}{\partial t} = \frac{kh^*}{\phi} \frac{\partial^2 h}{\partial x^2}$$ where $k$ is hydraulic conductivity $h^*$ is average height of water table and $\phi$ is specific yield. This equation is very much similar to diffusion equation used normally to model groundwater flow in confined aquifer as defined below.$$\frac{\partial h}{\partial t} = \frac{kd}{S} \frac{\partial^2 h}{\partial x^2}$$ where $d$ is thickness and $s$ is storativity of confined aqufier.  When I googled about Boussinest equation, it is noway similar to what I have presented above. My question is is 'linearized form of Boussinesq equation similar to diffusion equation in this case? If yes then how?&lt;/p&gt;&#xA;" OwnerUserId="5557" LastEditorUserId="5557" LastEditDate="2017-05-09T13:30:38.080" LastActivityDate="2017-05-09T13:30:38.080" Title="Linear Boussinesq Equation for groundwater flow in inconfined aquifer?" Tags="|models|hydrology|groundwater|water-table|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10346" PostTypeId="1" CreationDate="2017-05-09T10:31:11.290" Score="8" ViewCount="354" Body="&lt;p&gt;Note: edited based on helpful comments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In &lt;em&gt;Walking with Cavemen&lt;/em&gt;, Robert Winston claims an African rainforest existed 8 mya, but by 4 mya it was gone. He attributes this to newly Himalayas-triggered Indian monsoons, which prevented rainfall from reaching Africa. However, it's my understanding that India collided with the rest of Asia circa 50 mya. So why did the monsoons take so long?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Multiple comments have noted that Winston should have credited the monsoons to the Tibetan plateau. Either way my assumption is that, until the mountains had been pushed up far enough, they didn't threaten the forest's rain supply. On a linear approximation, by 8 mya the Himalayas' mean height would be approximately 85% of its present value, which bounds the &quot;critical value&quot; of the altitude as a percentage of its current one. A similar calculation applies for the Tibetan case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why did the motion of India lead to a multi-stage mountain formation? How did the timing of these effects influence Africa?&lt;/p&gt;&#xA;" OwnerUserId="7803" LastEditorUserId="7803" LastEditDate="2017-05-09T13:17:09.167" LastActivityDate="2017-06-08T21:37:10.933" Title="Timeline of Himalayas/Tibetan plateau formation" Tags="|precipitation|tectonics|ecology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10347" PostTypeId="1" CreationDate="2017-05-09T15:42:08.817" Score="3" ViewCount="1641" Body="&lt;p&gt;I know isotropic means equal properties in all directions , but the term &quot;transverse&quot; is not making it easy for me to understand.&lt;/p&gt;&#xA;" OwnerUserId="7538" LastActivityDate="2017-06-14T04:38:19.003" Title="what is a transverse isotropic rock?" Tags="|geology|rocks|structural-geology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10348" PostTypeId="2" ParentId="10344" CreationDate="2017-05-09T16:19:52.070" Score="10" Body="&lt;p&gt;Looks like Cirrus Fibratus (Ci fib) to me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See e.g. &lt;a href=&quot;http://www.wolkenatlas.de/wolken/wo10219.htm&quot; rel=&quot;noreferrer&quot;&gt;Wolkenatlas&lt;/a&gt; or &lt;a href=&quot;http://www.clouds-online.com/cloud_atlas/cirrus/images/cirrus_fibratus_10.htm&quot; rel=&quot;noreferrer&quot;&gt;Clouds Online&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding the formation of Ci fib, &lt;a href=&quot;http://namesofclouds.com/cirrus/cirrus-fibratus.html&quot; rel=&quot;noreferrer&quot;&gt;Name of Clouds&lt;/a&gt; says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Cirrus fibratus clouds are formed when winds at high altitudes are strong and flow over the cold air from below. The combination of the warm air and the moisture is usually unevenly distributed hence the trail of fine fibers at the ends of such clouds.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7427" LastEditorUserId="7427" LastEditDate="2017-05-09T21:02:21.283" LastActivityDate="2017-05-09T21:02:21.283" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10349" PostTypeId="2" ParentId="10347" CreationDate="2017-05-09T20:29:35.770" Score="0" Body="&lt;p&gt;As I understand it, &quot;tranverse isotropy&quot; has to do with seismic properties of a rock, a rock unit, or even a specific mineral. It's an important term because even though a rock may appear &quot;isotropic&quot; visually, it may have an internal fabric (invisible to unassisted eyes) that treats seismic waves differently depending the axes through which they are propagated. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Internal fabrics can be the result of crystalline alignment from high temperature shearing and strongly aligned microcracking, to cite just two examples. There are fierce debates regarding the seismic properties of minerals in the mantle and there are few specialized labs that can seismically test these unstable, high-pressure minerals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, a mylenite can be a mineralogically isotropic rock type but has an distinctly aligned mineral fabric that may do strange things to sound waves when they pass through: reflection, refraction, and polarization come to mind. Without knowing of the existence of this mylenite, in this example, a seismologist might mistake this highly reflective mylenitized unit for something very different. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is not just a minor detail of a rock property but an important component behind understanding seismic transmission and reflection for exploration geologists as well as mantle geophysicists.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-05-09T20:29:35.770" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10350" PostTypeId="2" ParentId="10346" CreationDate="2017-05-09T20:49:36.590" Score="2" Body="&lt;p&gt;Drying out of North Africa is likely the result of something far more local. I've never heard of the either the Tibetan Plateau or the growing Himalaya as causing changes to Africa's monsoons and always understood the connection between Milankovich cycles and the consequences of glaciation. According to this study, which modelled weather patterns of the time:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nature.com/nature/journal/v513/n7518/full/nature13705.html#affil-auth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Aridification of the Sahara desert caused by Tethys Sea shrinkage during the Late Miocene&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The drying of Africa started much earlier and was likely related to orbital cycles of glaciation-induced drying of the Mediterranean region.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Through a set of experiments, we demonstrate that the African summer monsoon was drastically weakened by Tethys Sea shrinkage, allowing arid, desert conditions to expand across north Africa. Not only did the Tethys shrinkage alter the mean climate of the region, it also enhanced the sensitivity of the African monsoon to orbital forcing, which subsequently became the major driver of Sahara extent fluctuations.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-05-09T20:49:36.590" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10351" PostTypeId="1" CreationDate="2017-05-09T21:06:20.130" Score="4" ViewCount="57" Body="&lt;p&gt;I want to analyze how the environmental conditions along the migratory route of a bird are related to the environmental conditions found at the breeding ground (which it is at high latitudes and we assume the rate of change is faster than at the stopovers). The environmental conditions are the NDVI, temperature, growing degree days.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it enough with a simple correlation analysis or is there's another approach to make the analysis more robust?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;thanks a lot in advance for your answers!&lt;/p&gt;&#xA;" OwnerUserId="7256" LastActivityDate="2017-05-09T21:06:20.130" Title="How can I analyze how environmental conditions are related among different sites?" Tags="|climate-change|temperature|correlation|natural-conditions|ndvi|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10352" PostTypeId="2" ParentId="10332" CreationDate="2017-05-09T21:10:24.257" Score="5" Body="&lt;p&gt;Groundwater ages vary enormously across the globe and with depth: from hours in parts of Florida and areas with Karstic geology, to tens of thousands of years in the American breadbasket, all the way to several billion years as was recently discovered in Canada. Remember that some of this groudwater may be perfectly drinkable, while by far, most of it will be a hot, salty, crappy-tasting mess.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for how long will it take for pesticide to travel down 40 meters.... that all depends on the hydraulic conductivity of everything between the source and your groundwater: a thin clay layer may be enough to block all downward progress and divert flow horizontally, extending the travel-time considerably. In dry areas of the Western US, for example, a pesticide spill will NEVER successfully travel vertically downward to the water table as there is not enough rain to force percolation to depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, remember that pesticide toxicity is time dependent, especially in the sub-surface. A given pesticide will react with water chemistry, soil minerals, and with groundwater bacteria; it begins decomposing immediately and doesn't stay poisonous forever. Hydrogeologist can effectively date the source of a pesticide (and most common contaminants) plume by looking at degradation products.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-05-09T21:10:24.257" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10353" PostTypeId="2" ParentId="10341" CreationDate="2017-05-09T22:36:02.423" Score="1" Body="&lt;p&gt;I would agree with your hypothesis, but I must point out that it will likely break down further and further as you approach the tropopause. Whether the ISA model is actually a average, I cannot say. However, the idea that the ISA model is a horizontal average is plausible.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-05-09T22:36:02.423" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10354" PostTypeId="2" ParentId="10290" CreationDate="2017-05-10T03:32:09.073" Score="1" Body="&lt;p&gt;The 5 factors you mention are not nearly as important to the effect you're asking about as another, more fundamental factor: &lt;strong&gt;time&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you've read my answer to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/10068/if-the-earth-is-a-globe-what-causes-temperature-differences-across-lines-of-lat/10073#10073&quot;&gt;this other question&lt;/a&gt;, you should understand that all of the factors you mention would create temperature differences at different latitudes &lt;em&gt;whether the Earth is tilted on its axis or not&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But because the Earth's axis is tilted, at some parts of the year the regions of the Earth tilted towards the Sun (in &quot;summer&quot;) receive sunlight a greater proportion of the day than the regions pointed away (in &quot;winter&quot;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not only that, because of the more direct angle of the Sun the factors you list mean that the regions in &quot;summer&quot; are heated better during the day than the regions in &quot;winter&quot;. &#xA;And this adds up over all the days of summer or winter until the Earth's orbit reorients the axis relative to the Sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or even more succinctly, &lt;strong&gt;&lt;em&gt;summer is hotter because the Sun is higher in the sky for more of the day&lt;/em&gt;&lt;/strong&gt;. &lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2017-05-10T03:59:32.387" LastActivityDate="2017-05-10T03:59:32.387" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10355" PostTypeId="1" CreationDate="2017-05-10T05:15:42.307" Score="4" ViewCount="951" Body="&lt;p&gt;How can scientists measure chemical composition (oxygen, nitrogen etc) and temperature on other planets without being there? &lt;/p&gt;&#xA;" OwnerUserId="8128" LastEditorUserId="2570" LastEditDate="2017-05-10T07:39:14.090" LastActivityDate="2017-05-10T07:39:14.090" Title="How can scientists measure chemical composition on other planets?" Tags="|atmosphere|planetary-science|atmospheric-chemistry|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10356" PostTypeId="2" ParentId="10355" CreationDate="2017-05-10T06:49:48.437" Score="5" Body="&lt;p&gt;Scientists can measure the chemical composition of the atmosphere of other planets using spectroscopy.  Each molecule in the atmosphere absorbs and re-radiates at specific frequencies of light that are a function of temperature and unique to the specific type of molecule.  For more information see &lt;a href=&quot;https://en.wikipedia.org/wiki/Extraterrestrial_atmosphere&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Extraterrestrial_atmosphere&lt;/a&gt; and &lt;a href=&quot;http://www.physics.uu.se/research/astronomy-and-space-physics/research/planets/exoplanet-atmospheres/&quot; rel=&quot;noreferrer&quot;&gt;http://www.physics.uu.se/research/astronomy-and-space-physics/research/planets/exoplanet-atmospheres/&lt;/a&gt; .&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-05-10T06:49:48.437" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10357" PostTypeId="1" AcceptedAnswerId="10358" CreationDate="2017-05-10T07:05:17.730" Score="4" ViewCount="4769" Body="&lt;p&gt;What part of the Mississippi River becomes &lt;strong&gt;unnavigable&lt;/strong&gt; (either freezes or accumulates too much ice to navigate) during an average winter? Perplexingly I could not find this through Google. I suppose &lt;strong&gt;no&lt;/strong&gt; part could become unnavigable all year-round? But that seems unlikely to me as the Mississippi reaches well into Minnesota.&lt;/p&gt;&#xA;" OwnerUserId="2733" LastActivityDate="2022-05-28T21:27:40.430" Title="During an average winter, what part (if any) of the Mississippi River becomes unnavigable?" Tags="|climate|rivers|ice|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10358" PostTypeId="2" ParentId="10357" CreationDate="2017-05-10T11:17:02.717" Score="5" Body="&lt;p&gt;Upper Mississippi river near St Paul Minnesota is closed December - March.  US Army Corp of Engineers is responsible river navigation in the United States.  From &lt;a href=&quot;http://www.winonapost.com/Community-Record/Cops-and-Court/ArticleID/46981/Corps-closes-books-on-another-Upper-Mississippi-navigation-season&quot; rel=&quot;noreferrer&quot;&gt;winonapost.com&lt;/a&gt;, (from 2015) the article states that all vessels need to be south of Lock and Dam 9, near Lynxville, Wisconsin.  Sounds like the upper river is closed so locks can be dewatered and maintanence performed.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My guess is most of the Mississippi river remains open to navigation south of Wisconsin during the winter. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.mvr.usace.army.mil/Missions/Navigation.aspx&quot; rel=&quot;noreferrer&quot;&gt;US Army Corp of Engineers river navigation site&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-05-10T11:17:02.717" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10360" PostTypeId="1" AcceptedAnswerId="10363" CreationDate="2017-05-11T02:23:18.750" Score="7" ViewCount="1841" Body="&lt;p&gt;I'm interested in fluorite (Since Fluorine is my favorite element, and I wanted a sample of it, even if bonded, but I don't want to buy it; that would be no fun), and I'm curious if it can be found on Long Island, New York. Where would the largest geologic formations be that are accessible?&lt;/p&gt;&#xA;" OwnerUserId="8138" LastEditorUserId="1149" LastEditDate="2017-05-12T15:15:29.427" LastActivityDate="2017-05-13T19:46:43.953" Title="Where can fluorite be found on Long Island, New York?" Tags="|geology|geochemistry|mineralogy|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10361" PostTypeId="2" ParentId="5332" CreationDate="2017-05-11T03:25:52.377" Score="0" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Mountain ranges are usually formed as orogeny where tectonic plates collides, known as convergent boundaries.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;While this is true in certain situations, it doesn't begin to explain how the vast majority of the earth's mountains are formed. In the global map below:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/chsif.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/chsif.jpg&quot; alt=&quot;Global surface map&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;we see that the edges of many tectonic plates are edged by spreading ridges and subsequent mountain building. Obviously, most mountain building is actually the result divergent tectonics, and not convergent. Curiously, there is no interesting conversation about &amp;quot;how these processes work&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Nevertheless, it is interesting that Mid-Ocean Ridges as well as most continental margin mountains are aligned north-south. However, there is little reason to believe that mantle convection and thus plate motion MUST operate in this fashion and that it has always done so.&lt;/p&gt;&#xA;&lt;p&gt;There is plenty of paleomagnetic evidence for landmasses moving in a wide variety of directions in the geologic past, that resulted in the creation of supercontinents. Today's N/S orientation may simply be an artifact of how the last supercontinent was broken up, and not evidence of the orientation of a permanent deep, driving force.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-05-11T03:25:52.377" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10362" PostTypeId="1" CreationDate="2017-05-11T04:36:28.250" Score="3" ViewCount="34" Body="&lt;p&gt;Caliches are signature features of many arid soils. In addition to the typical places of formation in deserts, they also occur in parts of the Tibetan plateau. Can they also form in polar climates? If not, why not?&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-05-11T04:36:28.250" Title="Can caliches form in arctic soils?" Tags="|soil|soil-science|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10363" PostTypeId="2" ParentId="10360" CreationDate="2017-05-11T11:18:37.347" Score="8" Body="&lt;p&gt;I do not know of fluorite being reported to occur on Long Island. If fluorite is found in NYC, the Natural History museum might have specimens.  You might try contacting a mineralogy / mineral collecting club on Long Island. Someone there would probably know for certain if fluorite can be found.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fluorite can be found in several limestone formations in New York. See map&lt;br&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/hNCs1.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hNCs1.jpg&quot; alt=&quot;Fluorite in New York&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Personally, I have collected fluorite from the Penfield Quarry near Webster New York during the mid 1980s.  Some of the waste rock from the quarry was used as breaker wall stone on the lake front in Webster New York.  You could probably still collect fluorite crystals there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a map of the lower 48 states showing mines where fluorite has been reported to occur.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XOQbJ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XOQbJ.jpg&quot; alt=&quot;Fluorite in lower 48 states&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other places I have personally collected fluorite&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Terlingua, Texas fluorspar mine (massive bedded fluorite)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Spearfish Canyon Black Hills South Dakota (fluorite in geodes in limestone)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Closed rock quarry in Pennsylvania near Breezewood, PA&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Locations where fluorite is still able to be collected.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Mines/Mountains near Socorro New Mexico&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Mt Antero in Colorado, at high elevation.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Bancroft Ontario - fluorite in calcite (fluorspar)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Burin Peninsula, Newfoundland, Canada (fluorspar)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wikipedia &lt;a href=&quot;https://en.wikipedia.org/wiki/Fluorite&quot; rel=&quot;noreferrer&quot;&gt;Fluorite&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maps created using  &lt;a href=&quot;http://digitalrockhound.blogspot.com/&quot; rel=&quot;noreferrer&quot;&gt;Digital Rockhounds Companion software&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="1149" LastEditDate="2017-05-11T11:29:02.047" LastActivityDate="2017-05-11T11:29:02.047" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10367" PostTypeId="2" ParentId="10157" CreationDate="2017-05-12T12:46:02.693" Score="9" Body="&lt;p&gt;According to the &lt;a href=&quot;http://cdiac.ornl.gov/oceans/ndp_067/other067.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;US Carbon Dioxide Information Analysis Center&lt;/a&gt; :&lt;/p&gt;&#xA;&lt;p&gt;Though in their data table they use the term &amp;quot;ppmv&amp;quot;, they explain:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The CO2 mixing ratios are reported as micromoles per mole (µmol/mol = ppmv) of dry air in the World Meteorological Organization (WMO) X85 mole fraction scale, traceable to primary standards at the Scripps Institution of Oceanography (SIO)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is further explained in &lt;a href=&quot;https://www.esrl.noaa.gov/gmd/ccl/co2report.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;The WMO Mole Fraction Scales for CO2 and other greenhouse gases, and uncertainty of the atmospheric measurements&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Abbreviations can be ppm, ppb, etc., whereas widely used abbreviations such as ppmv (the v is for volume) are wrong and should be abandoned. When reviewing papers, or when we are co-authors, we should convince first authors to abandon the ppmv notation. Volume has nothing to do with mole fraction.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Supposing you know the mole fraction, if you literally wanted to calculate the parts per million by volume, first you need to define what that would mean.  Are you interested in the ratio of the volume of CO2 separately isolated relative to the whole volume? Or are you interested in the volume of CO2 separately isolated, relative to the sum of all the gases separately isolated? For either of these methods, you would need to choose a temperature and pressure, such as the actual temperature and pressure of a sample, or standard temperature and pressure.&lt;/p&gt;&#xA;&lt;p&gt;Then you need an &lt;a href=&quot;https://www.nist.gov/sites/default/files/documents/srd/jpcrd516.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;equation of state&lt;/a&gt; at least for the CO2, that is more real than the ideal gas law, such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Van_der_Waals_equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;van der Waals&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2020-08-06T19:55:19.003" LastActivityDate="2020-08-06T19:55:19.003" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="10368" PostTypeId="1" CreationDate="2017-05-12T15:32:03.173" Score="4" ViewCount="169" Body="&lt;p&gt;I found allochthonous (I don´t know the 2 locations) fined grained&#xA;carbonate sediment in Ammonitico Rosso, which is possibly mudstone in&#xA;the South Iberian Peninsule, specifically in Carcabuey (Córdoba). It is&#xA;known that this sediment was formed in the Kimmeridgian and the area was&#xA;located in epioceanic shelf, upper waters/mixed layer. There are several&#xA;bioclasts in a good state of preservation, so it was covered quickly&#xA;enough (high deposition rate) to avoid dissolution. It is not&#xA;possible to know how much, I just have a hand sample from the field.&#xA;With this information: How can we explain these factors happen together?&#xA;- Fine grained sediment, so low energy - high deposition rate -&#xA;allochthonous carbonates - good state of preservation of bioclasts&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you need more information to try to answer this question, please let&#xA;me know.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you in advance&lt;/p&gt;&#xA;" OwnerUserId="8144" LastEditorUserId="8146" LastEditDate="2017-05-12T16:49:17.410" LastActivityDate="2017-05-16T04:55:39.723" Title="Deposition in epioceanic areas" Tags="|sedimentology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10371" PostTypeId="2" ParentId="10360" CreationDate="2017-05-12T20:37:56.657" Score="3" Body="&lt;p&gt;Long Island is one giant moraine so finding anything specific is basically a needle in a haystack without a really detailed survey and even then it is mostly luck. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This &lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/0878421807&quot; rel=&quot;nofollow noreferrer&quot;&gt;book&lt;/a&gt; will help you get the lay of the local geology. &#xA;The &lt;a href=&quot;http://www.newyorkmineralogicalclub.org/history/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NY Mineralogical Club&lt;/a&gt; might be a nice place to visit in general; they have some incredibly detailed surveys of the region. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.mindat.org/minloclist.php?m=1576&amp;amp;l=4002&quot; rel=&quot;nofollow noreferrer&quot;&gt;Minedat&lt;/a&gt; has a searchable mineral locality database, it pops up a few NY road cuts for fluorite as well as a couple fluorite &lt;a href=&quot;https://www.mindat.org/locdetailed-4002.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;variants&lt;/a&gt;.  Low percentage, but that's half the fun, right? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS: you are fairly close to the Franklin Mineral and Sterling Hill Mining Museum where you can find some really rare fluorescent minerals in the old talus piles, including fluorescent fluorites, and you can search them for a nominal fee. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="6703" LastEditDate="2017-05-13T19:46:43.953" LastActivityDate="2017-05-13T19:46:43.953" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10372" PostTypeId="1" CreationDate="2017-05-12T21:21:37.510" Score="2" ViewCount="104" Body="&lt;p&gt;Would the number of fish in a lake, along with how large they are, and how much they move, have a greater effect on the temperature of the lake than the angle of the sun's light hitting the surface of the lake?&lt;/p&gt;&#xA;" OwnerUserId="8151" LastEditorUserId="2536" LastEditDate="2017-05-12T23:40:10.380" LastActivityDate="2017-05-12T23:40:10.380" Title="Which has a greater effect on the temperature of a lake: the number of fish, or the angle of the rays of light hitting the surface of the lake" Tags="|insolation|" AnswerCount="0" CommentCount="10" ClosedDate="2017-05-13T19:40:54.793" ContentLicense="CC BY-SA 3.0" />
  <row Id="10375" PostTypeId="1" AcceptedAnswerId="10378" CreationDate="2017-05-13T20:54:53.740" Score="5" ViewCount="2058" Body="&lt;p&gt;For some time now, I've noticed that mountains in southeast Asia seem to be unusually &quot;jagged&quot; with steep surfaces.  My basic knowledge of how mountains are formed (via geologic processes) tells me that it's more common to find mountains like these in glacial areas (e.g. northern Canada, Norway, etc.), whereas those formed by tectonic plate collisions appear more &quot;traditional&quot; (e.g. main range of Himalayas, Andes, etc.), and geologically old mountains have a weathered appearance (e.g. Appalachians).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What caused/causes these SE Asian mountains to have their distinct appearance?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Examples (from Flickr):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HhsAj.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HhsAj.jpg&quot; alt=&quot;Mountains in Laos (Flickr)&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/v4b8U.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/v4b8U.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7505" LastActivityDate="2017-05-14T08:38:09.980" Title="What causes jagged appearance of mountains in SE Asia?" Tags="|plate-tectonics|mountains|geomorphology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10378" PostTypeId="2" ParentId="10375" CreationDate="2017-05-14T08:21:55.520" Score="7" Body="&lt;p&gt;David Hammen has already answered with the correct term in his comment. &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Karsts are formed as water dissolve rocks, typically &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonate_rock&quot; rel=&quot;noreferrer&quot;&gt;carbonates&lt;/a&gt; (as limestone or dolomite) or &lt;a href=&quot;https://en.wikipedia.org/wiki/Evaporite&quot; rel=&quot;noreferrer&quot;&gt;evaporites&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Karst landscapes can originate from karst caves, formed by groundwater flowing through the rocks. When the caves eventually collapse (&lt;a href=&quot;http://1.bp.blogspot.com/_JRp7TJWTx4A/S8Zvpncq70I/AAAAAAAAAVU/HPmQaOgb0d8/s1600/KarstDiagram-70pct-730206.jpg&quot; rel=&quot;noreferrer&quot;&gt;see image here&lt;/a&gt;) a rugged landscape is left behind. Karsts are also formed on the surface as limestone dissolves and forms spectacular landscapes, as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Tsingy_de_Bemaraha_Strict_Nature_Reserve&quot; rel=&quot;noreferrer&quot;&gt;Tsingy&lt;/a&gt; in Madagascar or from sea erosion, e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Calanque&quot; rel=&quot;noreferrer&quot;&gt;calanques&lt;/a&gt; (karstic valleys). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/t22se.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/t22se.jpg&quot; alt=&quot;(My own picture.)&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The landscape is also known as &lt;a href=&quot;https://www.britannica.com/science/pepino-hill&quot; rel=&quot;noreferrer&quot;&gt;Pepino Hills&lt;/a&gt; sometimes &lt;a href=&quot;https://en.wikipedia.org/wiki/Mogote&quot; rel=&quot;noreferrer&quot;&gt;mogotes&lt;/a&gt;, if they are surrounded by flat landscape. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another interesting feature is that as karst caves collapse, the cavity fills up with material from the ceiling and the cavity can continue to migrate upwards through the stratigraphy. Those karsts can be important channels for groundwater or petroleum. Sometimes the collapse material is more resistant to erosion than the surrounding rocks, and we get pinnacles of karst breccia left behind. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-05-14T08:38:09.980" LastActivityDate="2017-05-14T08:38:09.980" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10379" PostTypeId="1" CreationDate="2017-05-14T08:25:52.267" Score="1" ViewCount="1334" Body="&lt;p&gt;Can someone please explain to me (or give a source) how the crystallization diagram of the diopside-wollastonite-silica system looks. I am a new learner of geology and trying to learn ternary systems.&lt;/p&gt;&#xA;" OwnerUserId="8159" LastEditorUserId="94" LastEditDate="2017-05-14T17:10:01.013" LastActivityDate="2017-05-16T05:42:29.913" Title="Crystallization path of diopside-wollastonite-silica systems" Tags="|geology|geochemistry|petrology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10385" PostTypeId="1" CreationDate="2017-05-14T20:55:16.063" Score="2" ViewCount="2716" Body="&lt;p&gt;It is located in the middle of a dry desert in Mecca and the astonishing thing is all wells around Mecca dried out except this one!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So how can a small well, with a diameter of about 1.46 meter to 2.66 meter, and the depth of about 30 meters quench the thirst of billions of people from all over the world throughout centuries?&lt;/p&gt;&#xA;" OwnerUserId="8161" LastActivityDate="2017-05-15T03:16:54.143" Title="How come ZamZam water in Mecca never runs out?" Tags="|groundwater|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10386" PostTypeId="2" ParentId="10379" CreationDate="2017-05-14T21:53:50.423" Score="6" Body="&lt;p&gt;The diopside–wollastonite–silica system ($\ce{CaMgSi2O6-CaSiO3-SiO2}$) was never studied for crystallisation paths in igneous systems. This is not a system encountered in terrestrial magmas, so no one bothered.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it was studied as part of a more general lime–magnesia–silica ($\ce{CaO-MgO-SiO2}$) system by material scientists and they came up with this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LLEXa.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LLEXa.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.steeldata.info/inclusions/demo/help/diagram9.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source: Steel Data&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see small fields for &quot;Diop&quot; and &quot;wolla&quot; slightly above the centre of the diagram. This is not an easy diagram though, and it's of limited use to geologists. If you're studying ternary systems I recommend you go through these instead: &lt;a href=&quot;http://serc.carleton.edu/research_education/equilibria/ternary_diagrams.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ternary Phase Diagrams&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2017-05-16T05:42:29.913" LastActivityDate="2017-05-16T05:42:29.913" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10388" PostTypeId="1" CreationDate="2017-05-15T02:16:44.520" Score="5" ViewCount="73" Body="&lt;p&gt;Old faithful still erupts regularly, but at some point conditions in geology will change and it will cease activity.  &lt;a href=&quot;https://en.wikipedia.org/wiki/Geyser&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt; says that ~1300 geysers have erupted in Yellowstone, but only 1/3 of those are active in a given year.  Do geysers typically go dormant for long periods of time?  How long do they typically stay active before going extinct?  &lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-05-15T02:16:44.520" Title="How long do geysers typically stay active in Yellowstone?" Tags="|geology|geysers|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10389" PostTypeId="2" ParentId="10385" CreationDate="2017-05-15T03:16:54.143" Score="2" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Zamzam_Well#Technical_Information&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zamzam Well&lt;/a&gt; is located in the Wadi Ibrahim. It accesses water from the wadi alluvium and from the bedrock. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Water in the well comes from absorbed rainfall in the Wadi Ibrahim, as well as run-off from the local hills. Since the area has become more and more settled, water from absorbed rainfall on the Wadi Ibrahim has decreased.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-05-15T03:16:54.143" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10390" PostTypeId="1" CreationDate="2017-05-15T10:53:08.540" Score="6" ViewCount="124" Body="&lt;p&gt;I am running idealised supercell simulation using WRF model. The supercell storm is initiated with a thermal bubble. I just wonder if the thermal bubble is only affecting the initial temperature. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I ask because I am trying to calculate CAPE, and needed to set the parcel temperature. Parcel temperature is normally set to the environmental temperature at the surface. But since my simulation is initiated by a thermal bubble, I wonder if I should add the perturbed bubble temperature to the environmental temperature as my parcel temperature. Hope my question is clear.&lt;/p&gt;&#xA;" OwnerUserId="3063" LastEditorUserId="111" LastEditDate="2017-05-15T17:10:11.833" LastActivityDate="2018-10-22T18:00:26.503" Title="Does thermal bubble initiated in WRF dissipate over time?" Tags="|meteorology|atmosphere-modelling|wrf|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10391" PostTypeId="1" AcceptedAnswerId="10398" CreationDate="2017-05-15T17:17:27.807" Score="5" ViewCount="117" Body="&lt;p&gt;My text book says that parabolic dunes consist of consolidated limestone grains, but I wondered if  they have sand grains too, so I googled this issue and found that they consist of sands, but I am still perplexed, do parabolic dunes have both sand and consolidated limestone grains or they only contain one type of grains? And do they form exactly as other types of dunes (barchan dunes for example)?&lt;/p&gt;&#xA;" OwnerUserId="6908" LastEditorUserId="725" LastEditDate="2017-05-15T22:55:39.810" LastActivityDate="2017-05-16T04:34:12.317" Title="The grains of the parabolic dunes" Tags="|geology|wind|sedimentology|geomorphology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10392" PostTypeId="1" CreationDate="2017-05-15T17:42:46.360" Score="1" ViewCount="105" Body="&lt;p&gt;somebody told me it was a bottom value , but I still don't get the whole picture.&lt;/p&gt;&#xA;" OwnerUserId="7538" LastActivityDate="2017-05-15T18:26:33.073" Title="What does mean &quot;background&quot; in statistics or geostatistics?" Tags="|statistics|" AnswerCount="1" CommentCount="1" ClosedDate="2017-05-16T12:39:09.380" ContentLicense="CC BY-SA 3.0" />
  <row Id="10393" PostTypeId="2" ParentId="10392" CreationDate="2017-05-15T18:17:18.850" Score="1" Body="&lt;p&gt;&lt;strong&gt;Note:&lt;/strong&gt; Since there is more than one use case of &lt;em&gt;background&lt;/em&gt; in geostatistics, I will pick only one. If this is not the right &lt;em&gt;background&lt;/em&gt; you are looking for, please edit and clarify your question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Answer:&lt;/strong&gt; A data point can be given by an absolut value &lt;code&gt;A&lt;/code&gt; or a background value &lt;code&gt;B&lt;/code&gt; plus a deviation &lt;code&gt;D&lt;/code&gt; where &lt;code&gt;B + D = A&lt;/code&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Example:&lt;/strong&gt; If you are looking at a map showing the mean temperature of year &lt;code&gt;X&lt;/code&gt;, you can look at the absolute field &lt;code&gt;A&lt;/code&gt; or on its deviation &lt;code&gt;D&lt;/code&gt; from the climatological year mean temperature of 1961-1990 &lt;code&gt;B&lt;/code&gt;. Sometimes the latter tells you more, depending on what you are interested in. Additionally, analyses and statistical methods are often applied to the deviation field instead of the absolute field to identify patterns.&lt;/p&gt;&#xA;" OwnerUserId="7427" LastEditorUserId="7427" LastEditDate="2017-05-15T18:26:33.073" LastActivityDate="2017-05-15T18:26:33.073" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10396" PostTypeId="1" AcceptedAnswerId="10397" CreationDate="2017-05-16T02:11:22.033" Score="8" ViewCount="436" Body="&lt;p&gt;Reading the &lt;a href=&quot;https://en.wikipedia.org/wiki/Broken_Hill&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia entry for the Australian town of Broken Hill&lt;/a&gt;, I came across the following piece of trivia (emphasis mine):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The &quot;broken hill&quot; that gave its name to Broken Hill actually comprised a number of hills that appeared to have a break in them. &lt;strong&gt;The broken hill no longer exists, having been mined away&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Surely there must be many other examples of this happening over the course of human history? I haven't been able to find any.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a term for mountains or hills that have been wiped out of existence due to mining or some other human activity? Or perhaps a list of such instances?&lt;/p&gt;&#xA;" OwnerUserId="8167" LastEditorUserId="2536" LastEditDate="2017-05-20T14:10:10.933" LastActivityDate="2024-02-11T12:19:26.840" Title="Is there a list of instances where mountains that have been mined out of existence?" Tags="|geology|mountains|mining|anthropocene|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10397" PostTypeId="2" ParentId="10396" CreationDate="2017-05-16T04:15:52.970" Score="6" Body="&lt;p&gt;Of course it happens elsewhere! However, I'm not sure there's a specific term, generally. Even in the &quot;montaintop removal&quot; country of Appalachia, there is no more prosaic term for the practice other than MTR. Too bad! It surely deserves a better term!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yldfY.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yldfY.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/vzeKK.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vzeKK.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/fedI8.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fedI8.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And...despite the complete excising of an entire mountain within the Oquirh mountains, even the Salt Lake City population has no term for Complete Mountain Removal!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cB9nB.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cB9nB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-05-16T04:15:52.970" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10398" PostTypeId="2" ParentId="10391" CreationDate="2017-05-16T04:34:12.317" Score="3" Body="&lt;p&gt;&quot;Sand&quot; is generally made up of whatever eroded rock type is nearby, minus the most easily eroded (and windswept) components. Typically, dunes are made up of highly resistant quartz grains, like the stuff that blows off of white sand beaches, for example, or feldspar sands which are even more erosion resistant (in certain cases). There are also very soft white gypsum sands in New Mexico who owe their existence to a nearby, inexhaustible supply of gypsum evaporites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for limestone sands, I've never heard of it although it's certainly possible given very specific circumstances. Nevertheless, that's not what controls dune morphology. Dune shape is almost entirely controlled by both wind and sand supply and similarly shaped dunes will occur regardless of grain composition if dune-forming components are the same.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-05-16T04:34:12.317" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10401" PostTypeId="2" ParentId="10368" CreationDate="2017-05-16T04:55:39.723" Score="2" Body="&lt;p&gt;A &lt;a href=&quot;https://en.wikibooks.org/wiki/Historical_Geology/Turbidites&quot; rel=&quot;nofollow noreferrer&quot;&gt;turbidity current&lt;/a&gt; can easily account for what you've observed. It could be part of a repetitive sequence of shallow angle sloughs caused by accumulating overburden, much like the Bouma Sequences that make up a Turbidite Deposit, or it could be a one-time gravity flow caused by an earthquake.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-05-16T04:55:39.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10402" PostTypeId="1" CreationDate="2017-05-16T09:44:57.350" Score="5" ViewCount="286" Body="&lt;p&gt;What is the difference between the Hydraulic diffusion equation and the Richards equation in groundwater dynamics? I want also to understand the difference between the different storage coefficients (Ss, S,..).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both are differential equations:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Diffusivity equation&lt;/strong&gt;: $$\ Ss. ∂h/ ∂t = −∇ ·(− K \nabla h) − G$$.(for Incompressible liquid)(the flux (q), source terms (G), the specific storage (Ss), hydraulic head (h)) (&lt;a href=&quot;http://en.wikipedia.org/wiki/Groundwater_flow_equation&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Richards equation&lt;/strong&gt; (headed based form (there two other forms of this equation)): $$C(h) . ∂h/∂t = ∇ · K(h)∇H$$ (specific moisture capacity C(h), (H) total hydraulic head, h is the matric head) (&lt;a href=&quot;http://en.wikipedia.org/wiki/Richards_equation&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Aren't they supposed to describe unsaturated flow ???  &lt;/p&gt;&#xA;" OwnerUserId="7995" LastEditorUserId="7995" LastEditDate="2017-05-16T12:18:56.260" LastActivityDate="2017-05-16T12:18:56.260" Title="What is the difference between the Hydraulic diffusion equation and the Richards equation in groundwater dynamics?" Tags="|models|soil|groundwater|fluid-dynamics|unsaturated-zone|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10404" PostTypeId="2" ParentId="10396" CreationDate="2017-05-16T17:43:01.010" Score="3" Body="&lt;p&gt;It happened and it is still happening:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the USA, there's the Bingham Canyon copper mine in Utah.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Australia, there's the Mount Whaleback and Mount Tom Price iron ore mines in Western Australia and former mines like Iron Knob and Iron Monarch in the Middleback Ranges of South Australia, near Whyalla.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In West Papuan province of Indonesia there's the Grasberg gold and copper mine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Ok Tedi copper and gold mine in Papua New Guinea is well into the process of mining the mountain.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-05-16T17:43:01.010" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10405" PostTypeId="1" AcceptedAnswerId="10408" CreationDate="2017-05-16T18:59:00.290" Score="17" ViewCount="3682" Body="&lt;p&gt;We just had visitors (in Monterey, California) from Montevideo, Uruguay.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not being very familiar with Uruguay, after having taken them to Big Sur, I asked them how far they lived from the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They said it was hours away, and that they lived on a river.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I later looked at a map and, &lt;a href=&quot;https://en.wiktionary.org/wiki/AFAICT&quot; rel=&quot;noreferrer&quot;&gt;AFAICT&lt;/a&gt;, they do live right on the Atlantic Ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If they view the river that flows into the Atlantic to the west of them to be the river they live on, that seems very odd to me - from my point of view, once the river dumps into the ocean, that's ocean, and the river stops where they meet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The body of water gets very much wider at that spot, so it certainly &quot;looks&quot; more like the ocean on the map than a continuation of the river. But it leads to the question: when a river dumps into an ocean, exactly where does it transition from being the river to being the ocean?&lt;/p&gt;&#xA;" OwnerUserId="3166" LastEditorUserId="6298" LastEditDate="2017-05-18T04:16:57.537" LastActivityDate="2017-05-18T04:16:57.537" Title="Where do rivers like the Rio de la Plata end and the ocean begin?" Tags="|ocean|oceanography|rivers|estuary|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10406" PostTypeId="2" ParentId="9463" CreationDate="2017-05-16T19:02:01.953" Score="2" Body="&lt;p&gt;&amp;quot;Proteins&amp;quot; isn't even consistent with the rest of the sentence in that quotation! It isn't principally protein.&lt;/p&gt;&#xA;&lt;p&gt;I think that paragraph is a paraphrase of the relevant paragraph from &lt;em&gt;Elements of the Nature and Properties of Soils&lt;/em&gt;, a standard introductory textbook, §4.1:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Most soil colors are derived from the colors of iron oxides and organic matter that coat the surfaces of soil particles. Organic coatings tend to darken and mask the colors derived from iron oxides.&lt;/p&gt;&#xA;&lt;p&gt;Because of the color changes that take place when various iron-containing minerals undergo oxidation and reduction, soil colors can provide extremely valuable insights into the hydrologic regime or drainage status of a soil. Bright (high-chroma) colors throughout the profile are typical of well-drained soils through which water easily passes and in which oxygen is generally plentiful. Prolonged anaerobic conditions can cause iron oxide coatings to become chemically reduced, changing high-chroma (red or brown) colors to low-chroma (gray, bluish or gray-green) colors, a condition referred to as &lt;strong&gt;gley&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;There are unusual cases with no (or only) organic matter, or with so little iron that iron oxides don't give color, in which case we see the underlying minerals, which can also have varying redox states.&lt;/p&gt;&#xA;" OwnerUserId="2639" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-05-16T19:02:01.953" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10407" PostTypeId="2" ParentId="10405" CreationDate="2017-05-16T19:24:41.657" Score="8" Body="&lt;p&gt;Typically, the river delta is considered the end of a river where it flows into either an ocean or lake.&lt;a href=&quot;https://i.stack.imgur.com/eU9VQ.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eU9VQ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the image shown below, the end of the river can be defined by either at the edge of the active delta plain. or the edge of the submerged delta plain&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Active boundary will vary due to tidal level, river level and the rate of subsidence of the of the delta plain or fan.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-05-16T19:24:41.657" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10408" PostTypeId="2" ParentId="10405" CreationDate="2017-05-16T21:03:05.987" Score="30" Body="&lt;p&gt;In the case of Río de la Plata, part of it is history and politics, and part of it is oceanography.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of Argentina and Uruguay considers Río de la Plata as a river (thus, the name, río) and as such it is the widest river in the world (maximum width &gt;200km). Río de la Plata is formed as the confluence of the Paraná and Uruguay rivers and results in a pretty wide estuary with Montevideo (Uruguay) in the northern shore. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As can be seen in the following satellite image, the combined discharge from the Paraná and Uruguay rivers creates a current that flows into the Atlantic Ocean and that is visible under calm wind conditions and high discharge periods.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/yQO2x.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yQO2x.jpg&quot; alt=&quot;Satellite Rio de la Plata&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://eoimages.gsfc.nasa.gov/&quot; rel=&quot;noreferrer&quot;&gt;https://eoimages.gsfc.nasa.gov/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Spanish and Portuguese explorers in the XVI century described Rio de la Plata as a &quot;Mar Dulce&quot; (freshwater sea). The Italian explorer Sebastiano Caboto explored the area and traded silver with the local Guaraní tribes and thus gave it the name of &quot;River of Silver&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In practice, the system is best described as an estuary: neither river nor ocean, but an area of freshwater and saltwater mixing. In the area of Montevideo, the salinity in spring is around 10 g/kg (way lower than ocean salinities ~30-35g/kg), but it can be higher in periods of low discharge. In the area of Buenos Aires, salinities below 5 g/kg are commonly found and thus, it makes sense to call it a river. Most oceanographers agree that the system is a salt-wedge estuary, with freshwater flowing near the surface toward the ocean and saltwater intruding landward near the bottom of the estuary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yLa4E.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yLa4E.png&quot; alt=&quot;Rio de la Plata salinity&quot;&gt;&lt;/a&gt;&#xA;Salinity of the Rio de la Plata: Source: Guerrero, R.A., Lasta, C., Acha, E.M., Mianzan, H., Framiñan, M., 1997. Hydrographic Atlas of the Río de la Plata. CARP-INIDEP, Buenos Aires, Montevideo. &lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2017-05-16T21:03:05.987" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10409" PostTypeId="2" ParentId="8298" CreationDate="2017-05-17T04:41:04.143" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Tectonic processes and erosion.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Well.....obviously: all surface features on our globe are caused, at base, by tectonics (uplift or subsidence) and erosion (knocking down or burying). To simplify: shifting plates cause mountains to build and basin to form and water falling from the sky erodes the rock and fills valleys with sand and gravel. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That, however, won't explain why a specific mountain will be shaped like a dog biscuit, or why a certain lake will look like a guitar. These are very specific results of erosion and, as such, are controlled largely by the internal fabric of the eroded body.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Water, as we all know, is the most important erosive force on earth and we also know that water will always seek the easiest path to the sea; it's a constant, stream of fine sandpaper always first eroding the softest, weakest spots of anything it touches. This would include the following:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&quot;Soft&quot; rock units like carbonates, shales, and chemically unstable rocks like serpentinites.&lt;/li&gt;&#xA;&lt;li&gt;Internal weaknesses like fault planes, joints, bedding planes, and folds, &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In the area highlighted by the OP, there is an abundance of these weaknesses for water's erosive power to exploit. That these weaknesses occur rather randomly in this area means that there is no specific orientation to drainages and mountain ridges. And this all makes sense given the context of the geologic history of the region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This area is home to the Fransiscan Assemblage of rocks. These mangled, misshapen, motley group of metamorphosed sedimentary rocks were once part of the accretionary wedge that built up at the bottom of a subduction zone. Tectonic forces bent, folded, cooked, smeared, and finally lifted these rocks, exposing their inherent weaknesses to the erosive power of water. The relatively random nature of these weaknesses results in a pretty random-looking erosional pattern.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Below are a few examples from the SW U.S. of what erosion does to uplifted units that contain regular and ordered weaknesses:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nlVl7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nlVl7.jpg&quot; alt=&quot;Jointing in bedrock-Southern Utah (I think)&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/SzdXA.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SzdXA.jpg&quot; alt=&quot;Erosion of uplifted dome.&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/YWP6R.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YWP6R.jpg&quot; alt=&quot;San Rafael Swell&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-05-17T04:41:04.143" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10414" PostTypeId="1" CreationDate="2017-05-17T20:39:53.223" Score="4" ViewCount="141" Body="&lt;p&gt;An estuarine turbidity maximum (ETM) is the area of an estuary that has maximum values in suspended particles in the water column. My questions are&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;What are the main characteristics of the ETM?&lt;/li&gt;&#xA;&lt;li&gt;How does the ETM affect biological organisms?&lt;/li&gt;&#xA;&lt;li&gt;How do the characteristics of the ETM vary depending on the type of estuary (salt-wedged, well-mixed, partially mixed)?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="111" LastActivityDate="2017-05-17T20:39:53.223" Title="How does the estaurine turbidity maximum vary depending on the type of estuary?" Tags="|ocean|rivers|estuary|turbidity|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10417" PostTypeId="1" CreationDate="2017-05-18T08:51:36.667" Score="14" ViewCount="4144" Body="&lt;p&gt;So I read somewhere that the inner core temperature of Earth might be as high as 7000 °C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Depending on the composition of the different layers towards the surface, the temperature should decline until the surface temperature of the air, at about average 14 °C, is reached.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This does however not seem to be the case as the temperature at first gets colder if one starts digging?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can this be explained?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And please excuse any naivety on my behalf as I´m no scientist.&lt;/p&gt;&#xA;" OwnerUserId="8182" LastEditorDisplayName="user12525" LastEditDate="2019-04-28T13:26:47.840" LastActivityDate="2019-08-13T16:58:45.113" Title="Why is the temperature between the earth core and surface not distributed linearly?" Tags="|geology|geophysics|geothermal-heat|geodynamics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10418" PostTypeId="2" ParentId="10417" CreationDate="2017-05-18T10:38:42.187" Score="17" Body="&lt;p&gt;The temperature does indeed increase with depth, something that is a problem in &lt;a href=&quot;https://en.wikipedia.org/wiki/TauTona_Mine&quot; rel=&quot;noreferrer&quot;&gt;deep mines&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole#Drilling&quot; rel=&quot;noreferrer&quot;&gt;deep drilling&lt;/a&gt;, but a benefit for &lt;a href=&quot;https://en.wikipedia.org/wiki/Geothermal_heating&quot; rel=&quot;noreferrer&quot;&gt;geotermal heating&lt;/a&gt;. The heat originates mostly from radioactive decay, but there is also a fraction of primordial heat from the formation of the Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a rule of thumb, geologists often assume 25°C/km temperature increasements within continental plates, but steeper increasements in oceanic plates or volcanic regions. The temperature curve is not constant, however. Due to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Convective_heat_transfer&quot; rel=&quot;noreferrer&quot;&gt;convection&lt;/a&gt;, the temperature increases slower with depth in the mantle and outer core. In that sense, the crust is an isolating cover. The temperature also varies due to subductions, the dynamics of the mantle and radioactivity within the crust. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The shallow soil temperature and the temperature in the air depend mostly on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_irradiance&quot; rel=&quot;noreferrer&quot;&gt;insolation&lt;/a&gt;, the radiation heat from the sun. The &lt;a href=&quot;http://journals.ametsoc.org/doi/full/10.1175/BAMS-D-14-00265.1&quot; rel=&quot;noreferrer&quot;&gt;average annual solar isolation&lt;/a&gt; is 1361 $W/m^2$ but only 20-500 $mW/m^2$ heat flux comes from Earth's internal heat production. However, this tiny fraction can sometime sbe important, e.g. to understand basal melting of ice sheets and glaciers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KSEzx.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KSEzx.jpg&quot; alt=&quot; Geothermal gradient adapted from Boehler, R. (1996). Melting temperature of the Earth&amp;#39;s mantle and core: Earth&amp;#39;s thermal structure. Annual Review of Earth and Planetary Sciences, 24(1), 15–40. CC&quot;&gt;&lt;/a&gt;&#xA;&lt;em&gt;Temperature gradient from crust to core. Recent research have improved the accuracy, but the principle in the figure remains (Annual Review of Earth and Planetary Sciences, 24(1), 15–40)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So why do you experience the temperature colder underground when you are digging? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The temperature at depth is the &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1111/j.1745-6584.2005.00052.x/abstract&quot; rel=&quot;noreferrer&quot;&gt;average temperature&lt;/a&gt; for day and night or even the year. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_irradiance&quot; rel=&quot;noreferrer&quot;&gt;energy from the sun&lt;/a&gt; reaches only the uppermost soil layer that &lt;a href=&quot;https://en.wikipedia.org/wiki/Absorption_(electromagnetic_radiation)&quot; rel=&quot;noreferrer&quot;&gt;absorbs&lt;/a&gt; heat but the &lt;a href=&quot;https://en.wikipedia.org/wiki/Thermal_conduction&quot; rel=&quot;noreferrer&quot;&gt;thermal conductivity&lt;/a&gt; is relatively low and it will not transport the heat down. The ground is &lt;a href=&quot;https://en.wikipedia.org/wiki/Volumetric_heat_capacity#Thermal_inertia&quot; rel=&quot;noreferrer&quot;&gt;reluctant to change&lt;/a&gt; its temperature regardless of variations on the surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How strongly you experience the temperature difference depends on where in the world you are and the local conditions. In some areas, the ground remains frozen, &lt;a href=&quot;https://en.wikipedia.org/wiki/Permafrost&quot; rel=&quot;noreferrer&quot;&gt;known as permafrost&lt;/a&gt;, even as the temperatures in the air can be pleasant during the summer and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Active_layer&quot; rel=&quot;noreferrer&quot;&gt;surface layer&lt;/a&gt; melts. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Permafrost#Base%20depth&quot; rel=&quot;noreferrer&quot;&gt;depth&lt;/a&gt; of the suggests that it's been formed over a long time. It reaches down to the depth where the mean temperature over hundreds or thousands of years is 0°C. At larger depths, the heat from the Earth's interior takes over and melts the frost. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/V0ARD.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/V0ARD.jpg&quot; alt=&quot;CC Original contributor, German Wikipedia user, &amp;quot;HylgeriaK&amp;quot;, translation by User:HopsonRoad. Wikimedia&quot;&gt;&lt;/a&gt;&#xA;&lt;em&gt;Temperature in the active layer and permafrost. The thickness of active layer is less than a couple of meters and the thickness of the permafrost depends on its age, the bedrock and the distance to the coast. (By German Wikipedia contributor, &quot;HylgeriaK&quot;)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;See the plot, linked by @JeopardyTempest in the comments to better understand the variations. Plotted on another scale and depth, annual variations would probably be seen as well.&lt;/em&gt; &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-05-18T13:32:53.247" LastActivityDate="2017-05-18T13:32:53.247" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="10420" PostTypeId="1" AcceptedAnswerId="11958" CreationDate="2017-05-18T14:35:11.563" Score="5" ViewCount="308" Body="&lt;p&gt;Why in some places (for example Dublin, Ireland) the thunder and lightning is such a rare thing even though it rains so frequently?&lt;/p&gt;&#xA;" OwnerUserId="8186" LastEditorUserId="6465" LastEditDate="2017-07-31T10:18:29.667" LastActivityDate="2017-07-31T10:18:29.667" Title="Why is thunder and lightning rare, even though it rains frequently?" Tags="|rainfall|lightning|thunderstorm|rain|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10421" PostTypeId="1" AcceptedAnswerId="13700" CreationDate="2017-05-18T16:02:38.027" Score="6" ViewCount="632" Body="&lt;p&gt;The Polar Circles are located at 66°33′46.7″ North and South, defining the minimum latitudes at which, for at least one 24 hour period during the year, the limb of the Sun never becomes invisible below the horizon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, because of the familiar phenomenon of &lt;a href=&quot;https://en.wikipedia.org/wiki/Twilight&quot; rel=&quot;noreferrer&quot;&gt;twilight,&lt;/a&gt; where the Sun indirectly illuminates Earth's ground level by scattered light from the atmosphere, localities well south of the Arctic Circle still experience long periods without actual nightfall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the latitudes at which there are at least 24 hours of continuous twilight per year? I am interested in both civil twilight – the point at which it's &quot;more or less night now,&quot; defined semi-arbitrarily as the Sun's center being 6 degrees below the horizon – and astronomical twilight, the point at which the sun is providing basically no illumination at all, defined as the Sun's center being 18 degrees below the horizon.&lt;/p&gt;&#xA;" OwnerUserId="8187" LastActivityDate="2018-03-24T04:01:11.730" Title="Where is the Arctic Circle for civil and astronomical twilight?" Tags="|geography|solar-terrestrial-physics|astronomy|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10422" PostTypeId="1" CreationDate="2017-05-18T17:34:50.977" Score="7" ViewCount="50" Body="&lt;p&gt;Plants re-emit a substantial fraction of their assimilated carbon into the atmosphere as Biogenic Volatile Organic Compounds (BVOCs) that affect the chemical and physical properties of the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If these plants/other similar vegetation have snow in there vicinity then what are the effects on the BVOC emissions from those plants. That is if a vegetation grows over a snow covered mountain then will the BVOC emissions be any different if there would have been no snow?&lt;/p&gt;&#xA;" OwnerUserId="7753" LastEditorUserId="7753" LastEditDate="2017-05-19T04:17:00.913" LastActivityDate="2017-05-19T04:17:00.913" Title="Effect of snow on BVOC emmisions of plants/trees" Tags="|biogeochemistry|snow|carbon|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10424" PostTypeId="1" AcceptedAnswerId="10459" CreationDate="2017-05-18T23:49:03.143" Score="7" ViewCount="375" Body="&lt;p&gt;I have been really interested in scientific hypotheses regarding abiogenesis, particularly the lipid-world hypothesis. However, I could not find information on the chemical pathway that leads to the synthesis of amphiphilic molecules such as fatty-acids. All I've been able to find is that it involves the mineral montmorillonite which allows the step-wise formation of fatty acids using carbon monoxide (CO) and hydrogen (H). However, I want to know the exact chemical process. Thanks! Here's a link to a video explaining &lt;a href=&quot;https://www.youtube.com/watch?v=GdNaP5BYaeU&quot; rel=&quot;noreferrer&quot;&gt;Abiogenesis&lt;/a&gt;.&lt;a href=&quot;https://i.stack.imgur.com/S16it.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/S16it.jpg&quot; alt=&quot;Here&amp;#39;s the information that I was able to gather from the video&quot;&gt;&lt;/a&gt;  &lt;em&gt;Note: I simplified the Montmorillonite structure and only included the parts that were involved (mainly the very negative oxygen atoms)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My hypothesis is the following: If alkanes were present in the earth's oceans, polymerization of fatty acids could have occurred via chain radical addition. However I'm not sure where the initial radical would come from on the montmorillonite clay particle. Just an idea.&lt;/p&gt;&#xA;" OwnerUserId="8190" LastActivityDate="2017-05-24T04:41:00.520" Title="Abiogenesis: Formation of Lipids from Montmorillonite" Tags="|geochemistry|biogeochemistry|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10425" PostTypeId="1" AcceptedAnswerId="10444" CreationDate="2017-05-19T00:34:24.770" Score="2" ViewCount="696" Body="&lt;p&gt;What is the proper way to calculate cumuluative moment magnitude if I know the moment magnitude of several earthquakes?&lt;/p&gt;&#xA;" OwnerUserId="5748" LastActivityDate="2017-05-22T17:52:22.693" Title="How to calculate cumulative moment magnitude?" Tags="|geophysics|seismology|earthquakes|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10426" PostTypeId="1" CreationDate="2017-05-19T12:21:04.187" Score="4" ViewCount="232" Body="&lt;p&gt;Suppose we are modeling 1D groundwater flow in an aquifer of extent $x$ from $A(x=0)$ to $C$. Lets say for unsteady state conditions, the input is at $A(x=0)$, we can model piezometeric response at $B (x&amp;gt;0)$ by heat equation. If I want to couple recharge from unstutrated zone into aquifer, should it be simply added to head value at $B$ or should it be implemented as boundary condition. Lets suppose we have already calculated recharge at point $B$ with Richard's equation. &lt;a href=&quot;https://i.stack.imgur.com/RiRPp.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RiRPp.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; I have tried to illustrate problem here. The problem is equivilant to 1D heat transport in a rod. &lt;/p&gt;&#xA;" OwnerUserId="5557" LastEditorUserId="10681" LastEditDate="2018-09-21T16:23:40.523" LastActivityDate="2018-10-21T17:00:39.623" Title="Coupling recharge with 1D groundwater flow model" Tags="|hydrology|models|groundwater|hydrogeology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10428" PostTypeId="1" AcceptedAnswerId="10431" CreationDate="2017-05-19T03:15:47.740" Score="3" ViewCount="1653" Body="&lt;p&gt;I read somewhere that the Chicxulub impact released the energy equivalent of anywhere from 100-300 teratons of TNT. That's an impressive amount of energy. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming a head on collision (according to &lt;a href=&quot;http://newsroom.ucla.edu/releases/moon-was-produced-by-a-head-on-collision-between-earth-and-a-forming-planet&quot; rel=&quot;nofollow noreferrer&quot;&gt;newer research&lt;/a&gt;), how would it compare to the impact that created our moon?&lt;/p&gt;&#xA;" OwnerUserId="8202" OwnerDisplayName="x0a" LastEditorUserId="887" LastEditDate="2017-05-19T19:05:45.630" LastActivityDate="2017-05-19T20:12:08.590" Title="How much energy released by the Theia-Gaia impact?" Tags="|earth-history|moon|earth-system|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10430" PostTypeId="2" ParentId="7894" CreationDate="2017-05-19T16:13:08.610" Score="0" Body="&lt;p&gt;A useful article on impact structures and ore deposits is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Economic Mineral Deposits in Impact Structures:&#xA;A Review &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.univie.ac.at/geochemistry/koeberl/publikation_list/265-Economics%20of%20craters-Impact%20Tectonics-2005.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.univie.ac.at/geochemistry/koeberl/publikation_list/265-Economics%20of%20craters-Impact%20Tectonics-2005.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8194" LastEditorUserId="1242" LastEditDate="2017-05-25T01:13:40.650" LastActivityDate="2017-05-25T01:13:40.650" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10431" PostTypeId="2" ParentId="10428" CreationDate="2017-05-19T19:34:58.197" Score="3" Body="&lt;p&gt;Here's a quick-and-dirty estimate.&#xA;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Gravitational_binding_energy&quot; rel=&quot;nofollow noreferrer&quot;&gt;gravitational self-energy&lt;/a&gt; of a uniform-density sphere is&#xA;$$&#xA;U = \frac35 \frac{GM^2}R&#xA;$$ &#xA;Let's assume Theia had the same mass and density as Mars, and that Gaia contained the rest of the mass of the Earth-Moon system.&#xA;The binding energies for the four bodies are then&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;theia/mars 4.82e+30 joules&#xA;gaia       1.90e+32 joules&#xA;earth      2.24e+32 joules&#xA;moon       1.24e+29 joules&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;You can see that Theia and the Moon contribute to the binding energy starting the third significant figure: moving the 90% of Theia's mass to Gaia, leaving us with the Earth and the Moon, must have released something like $0.3\times10^{32}\rm\,J$ of gravitational binding energy as heat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kinetic energies due to Earth's rotation and the Moon's orbit are irrelevant compared to Earth's binding energy --- the biggest contributor there is $0.25\times10^{30}\rm\,J$ associated with Earth's daily rotation.&#xA;It's probably safe to assume the same about the progenitors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apparently a &lt;a href=&quot;https://en.wikipedia.org/wiki/TNT_equivalent&quot; rel=&quot;nofollow noreferrer&quot;&gt;teraton of TNT&lt;/a&gt; is $4\times10^{21}\rm\,J$, if you insist on that comparison.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that I've assumed nothing about the geometry of the collision, whether it was head-on or glancing. I'm only making assumptions about the (well-known) final state and the (poorly constrained) initial state.&lt;/p&gt;&#xA;" OwnerUserId="887" LastEditorUserId="887" LastEditDate="2017-05-19T20:12:08.590" LastActivityDate="2017-05-19T20:12:08.590" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10432" PostTypeId="1" CreationDate="2017-05-19T19:41:11.290" Score="3" ViewCount="303" Body="&lt;p&gt;In school, I was acquainted with the Moh's hardness scale.  I wondered how malleability factors into this scale and was surprised to find there are &lt;a href=&quot;https://en.wikipedia.org/wiki/Hardness_comparison&quot; rel=&quot;nofollow noreferrer&quot;&gt;many different hardness scales&lt;/a&gt;:  the Rockwell scale, the Leeb scale, the Vickers, the Meyer, and I'm sure others.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are all the different hardness scales?  And, which ones are used in Earth Science?&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2017-05-22T02:05:31.670" LastActivityDate="2017-05-28T06:46:32.787" Title="What are the different hardness scales?" Tags="|geology|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10435" PostTypeId="2" ParentId="7894" CreationDate="2017-05-20T17:41:15.597" Score="1" Body="&lt;p&gt;It's worth noting that our planet was formed by &quot;meteorite&quot; impacts and that our own moon is the (geologically important) result of Mars smacking into our planet, but let's focus on impacts after, say, the Archaen. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we lived on the moon, impact craters would pretty important to our geology. As it is, it's perhaps a lot more important to our biology than to our geology, though strictly by association. For one thing, every meteorite that has ever hit an ocean basin (almost %75 of the earth's surface) has been plowed into a subduction zone; that includes monsters over 100km in diameter. As for those whose erosional remnants can be found on continents, finding them isn't easy and interpreting their formation isn't without controversy. In fact, finding many of them is a matter of walking back specific meteorite-related minerals to a likely source and focusing there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for diamonds, their occurrence in impacts is rare and, economic importance, rarer still. From Charlie Murphy's paper, &lt;a href=&quot;http://www.univie.ac.at/geochemistry/koeberl/publikation_list/265-Economics%20of%20craters-Impact%20Tectonics-2005.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Economic Mineral Deposits in Impact Structures&lt;/a&gt;:&#xA;A Review &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Diamonds generally occur in very small amounts in impact melt rocks.&#xA;  Grieve and Masaitis (1994) estimated an average concentration of about&#xA;  10 ppb.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As for economically important placer occurrences of industrial-grade diamonds, their source is still controversial. Geochemistry may prove a kimberlite source for these diamonds....just like those in South Africa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GLKJ2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GLKJ2.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A little bit of lunar scenery, here on earth.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastEditorUserId="20" LastEditDate="2017-06-03T11:16:57.173" LastActivityDate="2017-06-03T11:16:57.173" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10436" PostTypeId="1" AcceptedAnswerId="10606" CreationDate="2017-05-21T09:44:48.760" Score="3" ViewCount="124" Body="&lt;p&gt;&lt;a href=&quot;https://space.stackexchange.com/q/21587/12102&quot;&gt;This question&lt;/a&gt; describes a recently released explanation for flashes of light seen at the sub-solar point above Earth from the DSCOVR satellite, which is located in a special orbit between the Earth and Sun at a distance of about 1.5 million kilometers from the Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I won't reproduce the full question here. I'm asking about the discussion in the following paper about flat ice plates of order 100 microns in size at about 5,000 to 8,000 meters in altitude in thin clouds over land. Specifically the idea that areas that are tens of kilometers wide could contain plates that are all coplanar - parallel to the local Earth's surface and more importantly to each other, to within about 0.1 degrees.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While here is part of the discussion section of the paper, further explanation of the geometry of the satellite and Sun are in the &lt;a href=&quot;https://space.stackexchange.com/q/21587/12102&quot;&gt;linked question&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The discussion section of the very recent, on-line-available &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2017GL073248/epdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Terrestrial glint seen from deep space: oriented ice crystals detected from the Lagrangian point&lt;/a&gt; Alexander Marshak, Tamás Várnai and Alexander Kostinski, doi: 10.1002/2017GL073248 contains the following text:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Based on in-situ measurements of cirrus clouds, [Korolev et al., 2000; McFarquhar et al., 2002], tiny hexagonal platelets of ice, floating in air in nearly perfect horizontal alignment, are likely responsible for the glints observed by EPIC over land.  Because the EPIC instrument has a field of view of 0.62 degrees (see, &lt;a href=&quot;https://epic.gsfc.nasa.gov/epic&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://epic.gsfc.nasa.gov/epic&lt;/a&gt;) and a 2048x2048 pixels CCD, the specular signal within an angle of only $~3x10^{-4}$ degree (Fig. 2) must either contain smooth large oriented ice plates or smaller oriented platelets sending back diffracted light. Size distribution of such crystals depends greatly on cloud temperature and humidity but the range is from tens of microns to mm. Taking the wavelength of 0.5 micron and ice platelet size of 50 microns, yields the ratio or angular half-width of the diffraction lobe around the specular direction $10^{-2}$ or on the order of a degree [Crawford, 1968, p.486].  This is broader than the angular width of a pixel but narrower than change in the zenith direction over the area covered by a pixel (0.1°).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rlWIy.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rlWIy.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/f5q4H.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/f5q4H.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Is this collective horizontal alignment a known effect at even 1 degree, much less 0.1 degrees? Has this ever been measured to be true over such large areas, or even calculated? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although the result is preliminary and the discussion short, the authors suggest that this uniform horizontal alignment would not be an unusual occurrence at all. For example, later in the discussion:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Out of total 4106 images collected, 336 contain land-glint for the blue channel, which was chosen because it has the highest spatial resolution (to reduce the amount of data transmitted from DSCOVR, for all other channels four pixels are averaged onboard the spacecraft). Can one interpret this ratio 336/4106 = 8.2%? To exclude images with ocean at the location of possible glint, we divide the 8.2% by the land fraction in EPIC tropical band (1/4), yielding 32.8%. Hence, roughly one in three images with land in the center contains a glint from an ice cloud. This matches the fraction of Earth covered by ice clouds in tropics which is also about a third [King et al., 2013]. This agreement suggests that terrestrial glints seen from deep space supply efficient means of detecting cloud ice, reflecting at least a factor of 5-6 stronger that surrounding pixels and may substantially increase cloud albedo [Takano and Liou, 1989], relative to diffuse reflectance from randomly oriented ice particles. This is significant as cirrus clouds, composed mostly of aspherical particles, cover over 30% of the Earth surface and play a major role in the radiation budget [Stephens et al., 1990]. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm interested if there are there any explanations for &lt;em&gt;why&lt;/em&gt; this might happen. I know there is a phenomenon called a &quot;&lt;a href=&quot;https://commons.wikimedia.org/wiki/Category:Sun_pillars&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sun pillar&lt;/a&gt;&quot; that involves reflection off of such ice plates in the atmosphere, and I don't quite understand how the pillar is tall vertically but not wide laterally, but that is perhaps a different question. However, it may none-the-less involve the same kind of ice plate. So I've added this image of &quot;Sun pillar crystals&quot; to help with the discussion. In the explanation for the bright spots seen from DSCOVR, the light is at normal incidence to the planes of the crystals instead of oblique incidence shown here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TidNP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TidNP.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; &quot;Sun pillar crystals&quot; From &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Sun_pillars_crystal.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. The present question involves reflection at normal incidence, not oblique incidence shown here.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2017-05-21T09:58:00.790" LastActivityDate="2017-06-17T02:46:55.787" Title="Are there measurements or calculations that suggest atmospheric ice plates would be horizontal to within 0.1 degrees?" Tags="|atmosphere|clouds|ice|atmospheric-optics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10437" PostTypeId="1" CreationDate="2017-05-21T11:09:23.640" Score="7" ViewCount="266" Body="&lt;p&gt;What part of the Earth should be &quot;shaded&quot;; the poles or the equator?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the size of the sunbrella would depend on its ability to reduce certain wavelengths of radiation; what material or technology would best provide the shade, and when parked at L1 what size would it need to be?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once in place, could the amount of shade provided be regulated from earth?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the event of an approaching ice-age, could the sunbrella be adapted to intensify rather than decrease heat generation?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If it could be built, would our scientists know how to properly employ it? &lt;/p&gt;&#xA;" OwnerUserId="8203" LastEditorUserId="2536" LastEditDate="2017-05-28T09:43:35.833" LastActivityDate="2018-06-22T08:54:04.183" Title="Could a &quot;sunbrella&quot; parked at L1 block enough solar energy to counter global warming?" Tags="|meteorology|climate-change|geoengineering|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10438" PostTypeId="2" ParentId="10437" CreationDate="2017-05-21T14:16:31.663" Score="7" Body="&lt;p&gt;There are several journal articles on this topic, for example &lt;a href=&quot;http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0136648&quot; rel=&quot;nofollow noreferrer&quot;&gt;Optimal Sunshade Configurations for Space-Based Geoengineering near the Sun-Earth L1 Point&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Being truly at the L1 point is unsuitable because the radiation pressure of the photons acting on the shade (like solar sail) would disrupt the equilibrium, so the equilibrium point is shifted toward the sun from the L1 point and depends on the degree to which the shade reflects versus absorbs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The shade should be made of black material to minimize the effect of radiation pressure on the equilibrium point, thereby permitting it to be as close as possible to the L1 point, and closer to the Earth, where it can more effectively shade.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The size required is roughly a 1,500 kilometer diameter structure.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;All parts of the Earth would be shaded to some degree. From Earth, the sun would appear as it does during a &lt;a href=&quot;https://en.wikipedia.org/wiki/Transit_of_Venus&quot; rel=&quot;nofollow noreferrer&quot;&gt;transit of Venus&lt;/a&gt; or Mercury, but the position on the sun's disc would vary more with ones location on Earth since the shade would be much closer to Earth than Venus is.  &lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2017-05-24T15:26:10.197" LastActivityDate="2017-05-24T15:26:10.197" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10439" PostTypeId="1" CreationDate="2017-05-21T18:15:38.553" Score="3" ViewCount="1675" Body="&lt;p&gt;Map 1 shows a hillside with topographic contours at 50 m intervals. At Locality A a coal seam is exposed at the surface. The strike and dip of the seam is as indicated on the map. Use this information to draw strike lines for the coal seam and to show where else on the map the seam crops out. Shade the area of the land surface that lies above the coal seam.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How exactly do I work out how to draw the strike lines? The strike and dip is 115/10. What calculation do I use? Also, would the land surface above the coal seam be all the land to the north of it? &lt;a href=&quot;https://i.stack.imgur.com/FSwH8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FSwH8.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8204" LastEditorUserId="2570" LastEditDate="2017-05-21T20:17:20.020" LastActivityDate="2017-05-21T20:17:20.020" Title="Drawing strike lines when given strike and dip" Tags="|measurements|structural-geology|mapping|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10440" PostTypeId="1" AcceptedAnswerId="10443" CreationDate="2017-05-22T08:44:34.697" Score="8" ViewCount="8044" Body="&lt;p&gt;I'm currently building a weather station from scratch. It measures temperature, pressure, humidity, wind speed and direction. The end result shall be a weather station that sends out METAR weather messages so pilots can see live weather in our area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now I'm at the point where I'm writing the software and I have only little knowledge about meteorology. More specifically I ask myself when a meteorologist speaks about &quot;gusts&quot;. I know it's a wind speed peak, but I'm a bit puzzled how much faster compared to the average wind speed a gust must be to be actually called gust?&#xA;I was searching for some definitions, but I didn't really find anything useful.&lt;/p&gt;&#xA;" OwnerUserId="8205" LastEditorUserId="192" LastEditDate="2017-05-22T14:45:11.597" LastActivityDate="2017-05-25T22:30:43.870" Title="What is the definition of wind gust?" Tags="|meteorology|wind|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10441" PostTypeId="1" AcceptedAnswerId="10471" CreationDate="2017-05-22T11:55:38.763" Score="6" ViewCount="192" Body="&lt;p&gt;There seem to be many ideas for &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_sequestration&quot; rel=&quot;nofollow noreferrer&quot;&gt;carbon sequestration&lt;/a&gt;. The problem with anything electrochemical, is that unless it is solar-based, you're putting carbon into the atmosphere at probably a great rate than you're taking it out. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One interesting one seems to have been dumping &lt;a href=&quot;https://earthscience.stackexchange.com/a/5251/895&quot;&gt;limestone into the oceans&lt;/a&gt;, but &lt;a href=&quot;https://earthscience.stackexchange.com/a/6865/895&quot;&gt;calculations indicate that this will be too slow&lt;/a&gt; in terms of reaction mixing time, given our current CO2 emission rate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One wonders if you could build an extrochemical device based on solar power - to pass carbon dioxide through water, and create an ionic reaction that would lock up the carbon. But that would just be a less efficient version of photosynthesis. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: &lt;strong&gt;Will photosynthesis based carbon sequestration always be more efficient than other chemical means - in terms of rate?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Edit: A helpful question has been raised about what efficient means. It could be land use or energy consumption or rate. I meant rate. &lt;/p&gt;&#xA;" OwnerUserId="895" LastEditorUserId="895" LastEditDate="2017-05-26T09:20:57.503" LastActivityDate="2019-08-01T16:58:19.073" Title="Will photosynthesis based carbon sequestration always be more efficient than other chemical means - in terms of rate?" Tags="|carbon-cycle|biogeochemistry|carbon|limestone|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="10442" PostTypeId="1" CreationDate="2017-05-22T13:27:21.573" Score="3" ViewCount="343" Body="&lt;p&gt;My understanding of MSLP is that it is a normalized value for pressure at some location as if that location altitude was zero.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Thus, MSLP is not a function of elevation&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, after inspecting few cases, I am beginning to question the previous statement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Below is a screenshot from windy.tv for MSLP over the Himalayas from ECMWF with a high resolution of 9km:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/blVf7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://i.stack.imgur.com/blVf7.jpg&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Two main characteristics are obvious:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1- MSLP changes steeply between two adjacent points just due to the difference in elevation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2- MSLP over mountains seems to be a strong function of temperature (since it varies a lot over night and morning)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Are these two previous statement correct?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Can I normalize MSLP in terms of elevation?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get more insight at what I am trying to figure out: I am trying to interpolate observational MSLP data; however, since MSLP is very high on mountains I am getting wrong results around those points. In other words my algorithm would assume that a large area around the station that is on top of a mountain has an MSLP of 1020 while in fact, just as you move away few kilometers MSLP changes very quickly to 1010 because of the elevation drop, so how can I fix that?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Important note:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Theses &quot;anomalies&quot; in MSLP can only be seen with high resolution models for example they can be seen in ECMWF and not in GFS&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://imgur.com/a/vDkNh&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://imgur.com/a/vDkNh&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8206" LastActivityDate="2022-09-19T20:27:46.433" Title="How does MSLP change with elevation? trying to interpolate MSLP" Tags="|meteorology|measurements|barometric-pressure|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10443" PostTypeId="2" ParentId="10440" CreationDate="2017-05-22T14:38:39.343" Score="4" Body="&lt;p&gt;A US &lt;a href=&quot;https://graphical.weather.gov/definitions/defineWindGust.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;definition&lt;/a&gt; is:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Wind Gust: Is a sudden, brief increase in speed of the wind. According to U.S. weather observing practice, gusts are reported when the peak wind speed reaches at least 16 knots and the variation in wind speed between the peaks and lulls is at least 9 knots. The duration of a gust is usually less than 20 seconds. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So it must be 9 knots above the non-gust background.  &lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2017-05-22T14:38:39.343" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10444" PostTypeId="2" ParentId="10425" CreationDate="2017-05-22T17:52:22.693" Score="2" Body="&lt;p&gt;The moment magnitude ${\displaystyle M_{\mathrm {w} }}$  is a dimensionless number defined by Hiroo Kanamori as: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$M_{\mathrm {w} }={\frac {2}{3}}\log _{10}(M_{0})-10.7$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To sum several moment magnitudes we need to first convert them to  ${\displaystyle M_{\mathrm {0} }}$ (seismic moment) which you can simply sum and then convert it back&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;for each of the magnitudes you have - insert the magnitude into ${\displaystyle M_{\mathrm {w} }}$, solve for ${\displaystyle M_{\mathrm {0} }}$ and write down the answer.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Sum all the answers&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Insert the sum back into ${\displaystyle M_{\mathrm {0} }}$ and solve for ${\displaystyle M_{\mathrm {w} }}$&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="8209" LastActivityDate="2017-05-22T17:52:22.693" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10445" PostTypeId="2" ParentId="10442" CreationDate="2017-05-22T18:45:35.127" Score="3" Body="&lt;p&gt;So the Mean Sea level pressure is defined (simply) as &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Sea_level_pressure&quot; rel=&quot;nofollow noreferrer&quot;&gt;the pressure of the station, corrected to sea level&lt;/a&gt;. However, methodological problems occur over terrain, such as assumptions that may not be true.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A common method used to correct the pressure is called the barometric equation. One assumption, for example, is that the mean temperature of the previous 12 hours is used to determine the average temperature of the imaginary atmosphere (where the terrain actually is). Of course this generates problems, such as the idea that the mean temperature used is not representative, the lack of lapse rate information, etc. These problems can yield to extraordinary MSLP gradients that may or may not actually exist in reality.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-05-22T18:45:35.127" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10446" PostTypeId="1" CreationDate="2017-05-22T23:11:28.160" Score="4" ViewCount="136" Body="&lt;p&gt;I need to find out the largest amount of rainfall ever recorded in Atlanta, Georgia, USA. Where could I find this record?&lt;/p&gt;&#xA;" OwnerUserId="8213" LastEditorUserId="6093" LastEditDate="2017-05-26T13:58:01.550" LastActivityDate="2017-05-26T13:58:01.550" Title="Where can I find the record for the heaviest single-day rainfall ever recorded on any date at a specific location?" Tags="|rainfall|open-data|history|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10448" PostTypeId="2" ParentId="400" CreationDate="2017-05-23T04:57:37.247" Score="2" Body="&lt;p&gt;Regarding the &quot;and could it happen again&quot; part of your question; possibly, due to climate change. As others on here have noted, the original dust bowl was a combination of crappy soil conservation practices and a prolonged drought. Our soil conservation practices have improved a lot, but we still plant water-intensive crops like monoculture corn in places where it historically never would have grown. For instance, in the southern Great Plains where it's really dry and native vegetation usually consists of low-shrubs and short grasses. We're able to grow crops in these areas now, because of center-pivot irrigation technology (started in the 1940's) and groundwater pumping. But as our global climate system continues to warm and our groundwater resources become increasingly scarce, it's unlikely that we will be able to continue these practices in the future. Some authors think that a sudden, sustained drought in these areas consistent with what was observed in the dust bowl could lead to similar problems in the Great Plains observed in the 1930's. Just finished reading this paper in Nature Plants on this very topic : &lt;a href=&quot;https://www.nature.com/articles/nplants2016193&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/nplants2016193&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8216" LastEditorUserId="8216" LastEditDate="2017-05-23T22:24:54.783" LastActivityDate="2017-05-23T22:24:54.783" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10449" PostTypeId="2" ParentId="10446" CreationDate="2017-05-23T06:20:53.270" Score="6" Body="&lt;p&gt;Sounds like your question, like most questions about historical data, might be a little challenging to find the right source, as it often is around the world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But seeing you said Atlanta brightened my eyes!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For if one is seeking information for a US climate observation sites (most big cities, and a fairly reasonable web across the US... there's about 2-6 per Weather Service office), then there's a great source for historical data that, with a little looking around, allows you to fairly quickly answer quite a lot of interesting questions about your area once you get used to doing it... the NowData portal on your local National Weather Service Office's website.  To find this:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Go to the &lt;a href=&quot;http://www.weather.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Weather Service&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Click on your local area (which will take you to your local NWS Office webpage)&lt;/li&gt;&#xA;&lt;li&gt;Scan across the middle of the page about halfway up to find the climate and past weather drop down and you should come across the NowData link (for this one I had to click more in the menu)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Disappointingly tough to navigate to the NowData hub, but you only really need to find it approximately once, and then you're set!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To speed you along: &lt;a href=&quot;http://w2.weather.gov/climate/xmacis.php?wfo=ffc&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; is the direct link for the Atlanta (Peachtree City) area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then, once you get to the NowData page, you want:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The Atlanta area as the selected location (that will combine the past and current official Atlanta observation sites together to go back as far as possible for the official Atlanta observation)&lt;/li&gt;&#xA;&lt;li&gt;For product, click the calendar day summaries radio button&lt;/li&gt;&#xA;&lt;li&gt;The year range should likely be good... you want por- (por = period of record, meaning back to the very start of record keeping)&lt;/li&gt;&#xA;&lt;li&gt;Variable = Precipitation&lt;/li&gt;&#xA;&lt;li&gt;Summary = Daily Maximum&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;And viola, click Go, and you'll have it.  No, it's not a single list.  In some ways, to some, it may be better, it's a page of the maximum precipitation values every day of the year.  (Which allows you to see other things that might pique interest... such that [as is common in precipitation data due to such wild variability], the days calendar days on which Atlanta has never received an inch of rain are: February 29, April 21, May 10, May 12, September 9, September 12?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyways, it's a bunch of numbers... but the extra positive is that the maximums for each month are highlight red.  So just search through those quickly, you should find that the maximum 24-hour recorded rainfall in Atlanta history is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;1. 7.36&quot; on March 29, 1886&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second (assuming there was no additional great storm on a different March 29th!) was much more recent:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;2. 6.68&quot; on October 4, 1995&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You may well be able to dig around the climate category on that Peachtree City National Weather Service page and find more information on the major storms including those, and a better, simpler list.  But if not, at least the NowData offers the chance to reliably get answers to many questions like yours.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know, it's definitely not all the most intuitive.  At least it's consistent.  And, especially if you have some rudimentary spreadsheet experience, it can be made to tell you what you need rather quickly (in 15 years of meteorology, I still regularly use it myself.)  If somebody has a very reliable, comprehensive source for historical data that is fairly straightforward to the typical user, I'd be absolutely right at the front of the line to congratulate them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(And it is indeed a real pity, that in an era where the big concern is supposed to be changing climate, it still is fairly abstruse and convoluted to get great comprehensive climate information in an intuitive way from an official source)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But hopefully, while it's not absolutely beautiful in method, it not only answered your question, but given you and others the tool to answer the same question and quite a few others on temperature\precipitation climate\history for many other cities around the country!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6093" LastEditDate="2017-05-26T12:04:04.377" LastActivityDate="2017-05-26T12:04:04.377" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10450" PostTypeId="1" CreationDate="2017-05-23T06:42:01.977" Score="19" ViewCount="6009" Body="&lt;p&gt;I'm developing an ecology for a portion of my world that's geologically active and I remembered hearing that volcanic ash in soil makes it more fertile to agriculture. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;After extensive googling I've found surprisingly little information about the subject, and nothing convincing. Is this just a science &quot;fact&quot; that gets spread around without actually being completely true? If it is true, or partly true, what is the chemical process at work, and under what conditions is it the most effective?&lt;/p&gt;&#xA;" OwnerDisplayName="Nascence" LastEditorUserId="2536" LastEditDate="2017-05-23T07:01:47.593" LastActivityDate="2017-05-24T00:17:40.483" Title="Do volcanos really create fertile soil?" Tags="|volcanology|soil|ecology|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10451" PostTypeId="2" ParentId="10440" CreationDate="2017-05-23T07:09:00.607" Score="4" Body="&lt;p&gt;Doesn't appear to be great sources out there for some of this info!  (But then, that's what StackExchange has great promise in being!)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the US, &lt;a href=&quot;http://www.nws.noaa.gov/asos/pdfs/aum-toc.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this manual&lt;/a&gt; for the official instrument setup, as well as this &lt;a href=&quot;http://www.nws.noaa.gov/om/forms/resources/SFCTraining.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;old manual&lt;/a&gt; on how to take observations gives quite a bit of good detail on how wind observations are done...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the US, &lt;strong&gt;wind speed is the most recent 2 minute average&lt;/strong&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A thorough explanation for gusts for ASOS, which is about as readable as syrup:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In the manual procedure, a gust is reported when an observer sees&#xA;  rapid fluctuations in sensor wind speed indications with a variation&#xA;  of 10 knots or more between peaks and lulls during the 10-minutes&#xA;  before the observation. The reported gust is taken from the maximum&#xA;  “instantaneous” wind  speed  observed  during  this  period.  The &#xA;  average  2-minute  wind  is  used  to  report  wind  direction  and &#xA;  wind speed.  Conceivably,  an  average  2-minute  wind  speed  as low &#xA;  as  3  knots  (observed  in  the  last  minute)  may  be  reported&#xA;  with a gust of 10 knots (observed in the last 10 minutes).&#xA;  Observations of 5 knots with gusts of 10 to 15 knots, however, are the&#xA;  more common minimum values reported.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The ASOS algorithm also relies on a 10-minute observation period to &#xA;  determine gusts, but uses it in a different way. Once every 5 seconds,&#xA;  the ASOS computes the greatest 5-second average wind speed (and&#xA;  corresponding direction)  during  the past  minute,  and  once  each &#xA;  minute stores this information in memory for 12 hours.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Once every 5 seconds the ASOS computes the current 2-minute  average &#xA;  wind  speed  and  compares  it  with  the greatest  5-second  average &#xA;  wind  speed  during  the  past minute. If the current 2-minute average&#xA;  wind speed is equal to or greater than 9 knots and the greatest&#xA;  5-second average wind speed (during the past minute) exceeds the&#xA;  current 2-minute average speed by 5-knots or more, then the greatest&#xA;  5-second average speed observed during the past minute is stored in&#xA;  memory as a gust for 10 minutes.&#xA;  Once every 5 seconds, the ASOS compares the highest gust stored in memory &#xA;  for the past 10 minutes with the current 2-minute average wind speed.&#xA;  If the difference between the two is 3 knots or more, the current&#xA;  reported wind speed is greater than 2 knots, and the highest gust&#xA;  exceeds the minimum 5-second wind speed in the past 10 minutes by 10&#xA;  knots or more, then the highest gust stored in memory is designated as&#xA;  the reportable gust. This value is appended to  the  current  wind &#xA;  direction  and  speed  reported  in  the OMO,  computer-generated &#xA;  voice  messages, and  the METAR/SPECI  reports. The minimum gust speed&#xA;  reported by ASOS is 14 knots. Wind speeds from 3 knots and 11 knots&#xA;  may be reported with gusts to 14 knots. For example, a 2-minute&#xA;  average wind of 240 degrees at 10 knots with gusts to 20 knots is&#xA;  reported as:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;“24010G20KT.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Of course, the wind speed rules aren't standardized globally, as &lt;a href=&quot;http://www.wral.com/weather/blogpost/1283652/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this WRAL meteorologist discusses&lt;/a&gt;.  In fact, they aren't even entirely consistent in the US, as the Hurricane Center &lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/D4.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;uses&lt;/a&gt; a 1-minute average for sustained winds for hurricane intensity, and 3-5 second period for gusts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, even having done coursework on meteorological measurement systems, it's about as muddled to me now as it is to you. &lt;strong&gt;Probably report the most recent 2 minute average as the actual wind, and the highest instantaneous or 5-second average as the gust?&lt;/strong&gt; (with requirement that it exceeds set criteria as &lt;a href=&quot;https://earthscience.stackexchange.com/a/10443/6298&quot;&gt;DavePhD's answer&lt;/a&gt; alludes to, if you wish)&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-05-25T22:30:43.870" LastActivityDate="2017-05-25T22:30:43.870" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10452" PostTypeId="2" ParentId="10450" CreationDate="2017-05-23T07:14:16.110" Score="21" Body="&lt;p&gt;As always: It Depends.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming enough water and sunshine, crop growth rate boils down to the concept of limiting nutrients. These may be: nitrogen (via ammonia or nitrates), phosphorous (via phosphates), potassium, and sometimes others.  In typical continental settings (i.e. subduction related vulcanism), lavas may be enriched in potassium and phosphorous but not nitrogen. So there will be some effect from rock composition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Perhaps more important, there will be a refresh effect. If we have regular ash falls, this will 'top up' the soil as compared to normal soils, replacing nutrients. This is a similar effect to flood plains. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, to answer, it tends to be true that volcanic eruptions increase fertility, but the most effective kind are from explosive ash-fall vucanism you get in regions like Italy or the US Cascades. The kind of flood-plain basalts you get in Iceland probably don't help.&lt;/p&gt;&#xA;" OwnerUserId="8217" LastEditorUserId="6298" LastEditDate="2017-05-23T08:25:24.557" LastActivityDate="2017-05-23T08:25:24.557" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10453" PostTypeId="1" AcceptedAnswerId="13124" CreationDate="2017-05-23T14:10:18.493" Score="4" ViewCount="165" Body="&lt;p&gt;I am reading an Oceanography Textbook which explains that in the ocean, planetary vorticity tends to be much larger than relative vorticity therefore, the potential vorticity can be simplified to be f/H. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;This requires that the flow in an ocean of constant depth be zonal.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;...in general, currents tend to be east-west rather than north south. Wind makes small changes in relative vorticity, leading to a small meridional component to the flow.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If planetary vorticity is far larger than relative vorticity, how exactly do changes in f (planetary vorticity) cause ocean flow to be more zonal? &lt;/p&gt;&#xA;" OwnerUserId="8219" LastEditorUserId="8219" LastEditDate="2017-05-23T21:05:03.870" LastActivityDate="2018-01-18T02:37:50.803" Title="Why is the zonal component of flow in the ocean much larger than the meridional component" Tags="|oceanography|vorticity|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10456" PostTypeId="2" ParentId="10450" CreationDate="2017-05-23T22:15:43.117" Score="3" Body="&lt;p&gt;Plants follow the &lt;a href=&quot;https://en.wikipedia.org/wiki/Liebig%27s_law_of_the_minimum&quot; rel=&quot;nofollow noreferrer&quot;&gt;law of the minimum&lt;/a&gt;. There's a &lt;a href=&quot;https://en.wikipedia.org/wiki/Ecological_stoichiometry&quot; rel=&quot;nofollow noreferrer&quot;&gt;ratio&lt;/a&gt; at which nutrients occur in plant matter. If it can't get those amounts, it will be limited by the one nutrient that falls below the ratio. Let's say a plant wants to grow 123 grams of biomass. It needs 106g of carbon, 16g of nitrogen, and 1 g of Phosphorous (this is called the &lt;a href=&quot;https://en.wikipedia.org/wiki/Redfield_ratio&quot; rel=&quot;nofollow noreferrer&quot;&gt;Redfield ratio&lt;/a&gt;, and it occurs mostly in phytoplankton). OK, let's say it has just enough carbon and Phosphorous, but what happens when it only has 15 grams of nitrogen? It still has to maintain the ratio, so it winds up using only 99g carbon and 0.93g Phosphorous, even though it has more than enough carbon and phosphorous.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sometimes, nutrients come in different forms, and only some of these forms are easily accessible to plants. Certain nutrients cycle through these forms in different ways. Inaccessible nitrogen, for instance, can be fixated by certain kinds of bacteria to become accessible once again. Phosphorous on the other hand is much more likely to go from accessible to inaccessible, but accessible forms can be supplied by volcanic soils. I don't mean to say it's just Phosphorous causing growth after an eruption (it depends strongly on what gets released, as well as what limits the plant prior to eruption) but this is the sort of thing that can go on.&lt;/p&gt;&#xA;" OwnerUserId="8224" LastActivityDate="2017-05-23T22:15:43.117" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10458" PostTypeId="2" ParentId="10450" CreationDate="2017-05-24T00:17:40.483" Score="3" Body="&lt;p&gt;I disagree with the statement that flood-plain basalts don't make fertile soils. The most fertile soils in southeast Australia are on the Victorian volcanic plains. The soils of the Deccan Plateau of India are considered very fertile.  There are very fertile soils formed on the Columbia River basalts of eastern Washington state and Oregon as far as the Willamette valley. In addition to the soils formed in place, weathered basalt can contribute to the fertility of soils formed on transported sediments, e.g. the silty soil of the Palouse region in eastern Washington state.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lava flows may take longer to break down because ash fall has higher surface area but the flow tops are often rough and fractured, enhancing the weathering rate. Cinder cones and other 'mild' pyroclastic eruptions are also a feature of basaltic volcanism that contribute to faster weathering.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-05-24T00:17:40.483" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10459" PostTypeId="2" ParentId="10424" CreationDate="2017-05-24T04:41:00.520" Score="4" Body="&lt;p&gt;Good question! One that's stuck with me since reading about clay's purported role in providing scaffolding to early organic molecules in a Scientific American article from the late '80s. Many years later I ran into a bonafide clay scientist who said &quot;Of course!&quot; when I asked her about clay's role in establishing early life.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyway...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suspect that molecular attraction and ordering is more of a driver than a specific chemical process (but I'll claim ignorance here). What I have found is a slide from a talk entitled &quot;&lt;a href=&quot;http://www.astro.sunysb.edu/lattimer/AST248/lecture_13.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chemical Evolution Theory of Life’s Origins&lt;/a&gt;&quot; given at the State University of Stony Brook's Astronomy department in which the author highlights an underappreciated chemical property of clay sheets, namely that of mirror symmetry on opposing crystal faces. Recall that these sheets are actually molecular-thin crystals attached to each other by very weak bonds, the implication being that the crystal surfaces themselves are mildly charged providing a surface for monomers to automatically align:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/c1gyI.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/c1gyI.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Every physical separation between these crystals provides identical faces on opposing sides of the void. Do these faces act as holding jigs for water-borne monomers to line up into lipids? The authors lab results confirm this. However he provides no details for how, specifically, that catalysis happens. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's worth noting that this (clay-based) process sounds almost exactly the reverse  of chemical cracking of long-chain crude petroleum compounds in which naturally occurring molecular sieves are used to break bonds (and allow re-ordering of resultant fragments). From Wikipedia:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The catalytic cracking process involves the presence of acid catalysts (usually solid acids such as silica-alumina and zeolites) which promote a heterolytic (asymmetric) breakage of bonds yielding pairs of ions of opposite charges, usually a carbocation and the very unstable hydride anion. Carbon-localized free radicals and cations are both highly unstable and undergo processes of chain rearrangement, C-C scission in position beta as in cracking, and intra- and intermolecular hydrogen transfer. In both types of processes, the corresponding reactive intermediates (radicals, ions) are permanently regenerated, and thus they proceed by a self-propagating chain mechanism. The chain of reactions is eventually terminated by radical or ion recombination&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Here's another important paper that I wish I had more time to read: &lt;a href=&quot;https://www.bio-conferences.org/articles/bioconf/pdf/2015/01/bioconf-origins2015_00012.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Origins of life: From the mineral to the biochemical world&lt;/a&gt;, in which, among many other important things, the author writes, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;One of these involves enantioselective adsorption on crystal faces.&#xA;  Hazen et al. [13] have investigated the adsorption of the two forms of&#xA;  an amino acid (aspartic acid) on well-defined faces of calcite&#xA;  crystals. These faces themselves already possess the property of&#xA;  chirality, i.e. the arrangement of atoms exposed on the surface is not&#xA;  superimposable to its mirror image...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This paper is a pretty good resource. This &quot;brief guided tour through “mineral-based” prebiotic scenarios&quot; is clear and the references likely complete, and it also highlights the role of clays in storing molecular information, as well as the role of metal sulfides in establishing (maybe) early metabolic reactions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZiWLw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZiWLw.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let us know what you dig up!&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-05-24T04:41:00.520" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10460" PostTypeId="1" CreationDate="2017-05-24T09:46:38.700" Score="3" ViewCount="88" Body="&lt;p&gt;It seems, these &lt;a href=&quot;https://www.google.pl/maps/@23.5429234,24.8056825,3416m/data=!3m1!1e3?hl=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;white blotches&lt;/a&gt; are reflective enough that they &lt;a href=&quot;https://photo.stackexchange.com/q/89488/6544&quot;&gt;caused oversaturation of a spot of image&lt;/a&gt; taken from a satellite at the L1 lagrangian point (click to open at max resolution, the purple spot is squat in the middle of the picture).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oo4xd.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oo4xd.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MdmzW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MdmzW.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clear quartz crystals has been found nearby ( &lt;a href=&quot;http://www.b14643.de/Sahara/Geology_Gilf-Kebir/index.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt; ), but could it be this? Can quartz so clear and reflective appear in such abundance? Or is it some other cause?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(I thought it might be frost, which shows up on the desert in the mornings, but the photo taken from L1 places the point at peak of the summer with the Sun precisely in zenith above it; I doubt any frozen water could withstand that. Also, Wikimapia has some &lt;a href=&quot;http://wikimapia.org/#lang=pl&amp;amp;lat=23.730041&amp;amp;lon=25.039902&amp;amp;z=12&amp;amp;m=b&amp;amp;show=/32354362/Mars-Landscape/photo/4646691&quot; rel=&quot;nofollow noreferrer&quot;&gt;photos&lt;/a&gt; taken nearby with what looks like frost, but the daytime is obviously different).&lt;/p&gt;&#xA;" OwnerUserId="8232" LastActivityDate="2017-05-26T03:49:46.377" Title="What causes this white coloration of the ground in Gilf-Kebir?" Tags="|geology|minerals|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10463" PostTypeId="1" CreationDate="2017-05-24T18:12:21.313" Score="1" ViewCount="76" Body="&lt;p&gt;I am working on an important project please help!&lt;/p&gt;&#xA;" OwnerUserId="8178" LastActivityDate="2017-05-24T18:12:21.313" Title="How did the The Fukushima Nuclear Disaster affect Japan's vegetation?" Tags="|earthquakes|tsunami|" AnswerCount="0" CommentCount="7" FavoriteCount="0" ClosedDate="2017-06-18T20:06:17.880" ContentLicense="CC BY-SA 3.0" />
  <row Id="10468" PostTypeId="2" ParentId="10460" CreationDate="2017-05-26T03:49:46.377" Score="1" Body="&lt;p&gt;The white areas appear to be formed on the edge of elevated parts of the landscape and in low-lying flat areas. You can see this if you use Google Earth and looking at the elevation profiles along paths you sketch across the landscape. They don't appear to form at a particular elevation or other pattern that would indicate they are bedrock outcrops.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think the most likely possibility is that they are caliche deposits (calcium-carbonate cemented sediments), formed as water ran off of higher elevations, mobilizing calcium and evaporating to cause calcite saturation. They could be halite but I would expect more extensive deposits in the broader drainage areas if they were salt. They could have formed under wetter climate conditions. If you look at 23 degrees 14.053' North, 24 degrees 25.22' East, you can see deposits being covered by sand dunes.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-05-26T03:49:46.377" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10469" PostTypeId="1" AcceptedAnswerId="10470" CreationDate="2017-05-26T05:09:39.193" Score="3" ViewCount="798" Body="&lt;p&gt;Referring to the post: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.myroms.org/forum/viewtopic.php?f=30&amp;amp;t=3003&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.myroms.org/forum/viewtopic.php?f=30&amp;amp;t=3003&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understood how to calculate the slhf and sshf for 03, 06, 09 and 12 time steps. But I have values for 00, 15, 18 and 21 time steps as well. If the accumulated fields have base time for forecast values at 00:00:00 and 12:00:00, then how average values for 00, 12, 15, 18 and 21 time steps are calculated. I need average flux values for every 3-hour.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for your inputs. &lt;/p&gt;&#xA;" OwnerUserId="8244" LastActivityDate="2019-01-14T16:00:37.887" Title="How to calculate 3-hour flux values in ERA-Interim?" Tags="|climate|weather-forecasting|atmospheric-radiation|reanalysis|era|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10470" PostTypeId="2" ParentId="10469" CreationDate="2017-05-26T07:19:34.473" Score="5" Body="&lt;p&gt;After my original answer, and some back and forth in the comments, turns out I got the answer right by a bit of fools luck, and we sorted it out...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The thing is, despite flux being commonly thought of in physics as &lt;a href=&quot;https://betterexplained.com/articles/flux/&quot; rel=&quot;noreferrer&quot;&gt;BetterExplained.com suggests&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Timing: We measure flux at a single point in time. Freeze time and ask&#xA;  “Right now, at this moment, how much stuff is passing through my&#xA;  surface?”. If your field doesn’t change over time, then all is well.&#xA;  If your field does change, then you need to pick a point in time to&#xA;  measure the flux.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But, fairly counter-intuitively to many, meteorological models often, despite naming their variables as flux (such as sshf... &lt;strong&gt;s&lt;/strong&gt;urface &lt;strong&gt;s&lt;/strong&gt;ensible &lt;strong&gt;h&lt;/strong&gt;eat &lt;strong&gt;flux&lt;/strong&gt;), actually store them as &lt;strong&gt;accumulations&lt;/strong&gt;.  &lt;a href=&quot;https://www.ecmwf.int/sites/default/files/radiation_in_mars.pdf&quot; rel=&quot;noreferrer&quot;&gt;This ECMWF whitepaper&lt;/a&gt; on archive data specifications explains:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Physical fluxes archived by the ECMWF model are accumulated since the&#xA;  start of the relevant forecast, and therefore in units of&#xA;  $\mathrm{Jm^{−2}}$ (or $\mathrm{W m^{−2}\cdot s}$).  Thus, a daily&#xA;  mean (in $\mathrm{W m^{− 2}}$) is obtained by retrieving the&#xA;  accumulated fluxes at $\mathrm{t_1=t}$ and $\mathrm{t_2=t}+ \mathrm{24\;hours}$ (where&#xA;  $\mathrm{t}$ is the time of the start of the average), taking the difference&#xA;  and dividing by 86400, the number of seconds in a day.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, though intuitively, you might think the surface sensible heat flux at 6 hours would just be the sshf variable in the 6 hour file, it isn't.  To get the best estimate of the flux, you'd need to calculate it as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\mathrm{\frac{fluxvar_{(this\;timestep)} - fluxvar_{(previous\;timestep)}}{timestep_{(in\;hours)}\cdot3600}}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if you want to find the average flux between hours 3 and 6, you'd do:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\mathrm{\frac{fluxvar_{(t=6hr)} - fluxvar_{(t=3hr)}}{3\cdot3600}}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A couple of questions that Vidhi asked about that may be worthwhile understanding to others:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Why did the website quoted show the calculation as $\mathrm{({fluxvar_{(t=6hr)} - fluxvar_{(t=3hr)})/10800}}$, but not $\mathrm{({fluxvar_{(t=3hr)} - fluxvar_{(t=0hr)})/10800}}$... instead just using $\mathrm{{fluxvar_{(t=3hr)}}/10800}$&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Because indeed, in this strange accumulation form $\mathrm{fluxvar_{(t=0hr)}}$ by definition is zero.  The variable may or may not exist in the $\mathrm{t=0hr}$ file, but if it does, it should be pointless to include as it had better be 0 if it is indeed accumulation.&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;The site quoted only mentions hours 3, 6, 9, and 12.  I have 15, 18, and 21 as well, how do I deal with this?&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The same math applies... but remember, if you're dealing with forecast model archive (rather than reanalysis data), you want to use the shortest future hour possible.  So actually, rather than use 00Z's $\mathrm{t=12hr}$, you want to be using 12Z's $\mathrm{t=0hr}$, such that, when calculating the 9Z to 12Z flux average, best is$\mathrm{({fluxvar_{(12Z\;t=0hr)} - fluxvar_{(00Z\;t=9hr)})/10800}}$.  Because you only need steps 0, 3, 6, and 9 before the next archived model/reanalysis file (for a twice a day model), the 12/15/18/21 values really are the 0/3/6/9 values (just from the next model run).&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Anytime derived values (variables that aren't in the model itself, but require a formula to determine) need calculating, such as total surface heat flux, just make sure that when you combine the variables (in this case the shortwave, longwave, sensible, and latent heats), you only divide by the timestep once (don't divide by 10800 in the separate input variables beforehand, then divide by 10800 again after combining them).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The models are strange to many.  I just happened to incorrectly remember what a flux was, and get the &quot;divide by 10800&quot; math right (probably in part due to horror memories of working with similar files in years gone by!).  But hopefully this helps some confused people!  &lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-05-26T12:05:11.507" LastActivityDate="2017-05-26T12:05:11.507" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10471" PostTypeId="2" ParentId="10441" CreationDate="2017-05-26T09:45:46.463" Score="3" Body="&lt;p&gt;Rate.. no.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Brute Force&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;We can treat this as an industrial chemistry question. The brute-force method for carbon sequesteration is simply:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Extract CO2 from the air (using the acid/base chemistry, Sodium Hydroxide will scrub it as fast as you can supply air)&lt;/li&gt;&#xA;&lt;li&gt;Reduce CO2 to elemental carbon and oxygen. The exact details are not actually important - that's one for the industrial chemists - just the concept that it would take a LOT of energy. Basically as much energy as we currently get from fossil fuels, and then some, to extract and reduce at the same rate.&lt;/li&gt;&#xA;&lt;li&gt;Store the carbon somewhere safe, where it isn't going to catch fire. As long as it doesn't, it's stable on geological timescales.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The rate of this process is dependent on how much energy you are prepared to throw at it. A fleet of several thousand nuclear reactors running 24/7 on this problem would do it.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Burial&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Well, brute force sounds a bit expensive.. so we can try the approach mentioned by Jack R Woods. In this case, we capture CO2 (this still takes energy, although not much in theory), and pump it into thick basalt formations such as the ones in Iceland. Many flood-basalt igneous provinces have the combination of low-silica rocks and high porosity that are ideal for this kind of sequestration. The rate is limited by how fast you can capture CO2 out of the air.  You could imagine using a &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_updraft_tower&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;Solar updraft tower&quot;&gt;Solar Updraft Tower&lt;/a&gt; - this would give an air flow that you could extract CO2 from, and provide power for the process. If the reaction goes as planned, it's safe on geological timescales.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem is, as ever, getting enough resources to build these things on the scale required.&lt;/p&gt;&#xA;" OwnerUserId="8217" LastActivityDate="2017-05-26T09:45:46.463" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10472" PostTypeId="1" AcceptedAnswerId="10473" CreationDate="2017-05-26T10:34:28.977" Score="0" ViewCount="1249" Body="&lt;p&gt;From &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Rock_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Rock or stone is a natural substance, a solid aggregate of one or more minerals or mineraloids. For example, granite, a common rock, is a combination of the minerals quartz, feldspar, and biotite. The Earth's outer solid layer, the lithosphere, is made of rock.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Gallstone&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia page about gallstones&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A gallstone is a &lt;strong&gt;stone&lt;/strong&gt; formed within the gallbladder out of bile components&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So if rocks are stones, what type of rock are gallstones?&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Igneous rock is formed through the cooling and solidification of magma or lava.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Sedimentary rocks are types of rock that are formed by the deposition and subsequent cementation of that material at the Earth's surface and within bodies of water. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Metamorphic rocks arise from the transformation of existing rock types, in a process called metamorphism&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Gallstones don't fit into any of these categories so &lt;strong&gt;what type of rock is it?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="7897" LastEditorUserId="2536" LastEditDate="2017-05-28T09:35:05.373" LastActivityDate="2019-06-12T23:07:07.790" Title="If rocks are stones, what type of rock are gallstones?" Tags="|geology|rocks|terminology|" AnswerCount="3" CommentCount="2" ClosedDate="2019-06-19T12:12:28.313" ContentLicense="CC BY-SA 3.0" />
  <row Id="10473" PostTypeId="2" ParentId="10472" CreationDate="2017-05-26T11:59:31.070" Score="5" Body="&lt;p&gt;The nature of this question is more about biological chemistry than it is about earth science. This is because gall stones have nothing to do with geology, but chemical processes in the body.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consequently, it would be inappropriate to apply geological classifications, such as igneous, sedimentary or metamorphic, to gall stones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Due to the way gall stones are formed - layers of bile coating a nucleus - they could be describes as being &lt;a href=&quot;https://en.wikipedia.org/wiki/Concretion&quot; rel=&quot;noreferrer&quot;&gt;concretions&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-05-26T11:59:31.070" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10476" PostTypeId="1" AcceptedAnswerId="10484" CreationDate="2017-05-28T04:56:10.523" Score="6" ViewCount="636" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Natural_gas&quot; rel=&quot;noreferrer&quot;&gt;Natural gas&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...is a naturally occurring hydrocarbon gas mixture consisting primarily of methane, but commonly including varying amounts of other higher alkanes, and sometimes a small percentage of carbon dioxide, nitrogen, hydrogen sulfide, or helium.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I saw the graphic below in the BBC News article &lt;a href=&quot;http://www.bbc.com/news/world-us-canada-39428442&quot; rel=&quot;noreferrer&quot;&gt;Trump climate: Challenges loom after Obama policies scrapped&lt;/a&gt;. It lists natural gas as the source of about 33% of the US electricity generation in 2015, but also lists &quot;Other gases&quot; as the source of less than 1%. Presumably it is a meaningful fraction of that 1% or else the BBC would not have included it. While the source of the data is listed as the US Energy Information Agency, the graphic itself was prepared by the BBC if I understand correctly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are thee other gases &lt;em&gt;available from the Earth&lt;/em&gt; that could account for this fraction of 1%? I don't mean gases that are produced during an industrial refinement process, but perhaps gases that were simply separated. Just for example could it be natural propane? The same Wikipedia article mentions heavier hydrocarbons, but I don't understand if these are already present in the Earth and just being separated, or if they are produced primarily as reaction products. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT:&lt;/strong&gt; Based on comments, a substantially different source of gas that was chemically similar to natural gas would still be of interest. So just for example, methane from a bog should count in this case, since it does not involve many of the geological processes involved in the production of fossil fuels (e.g. the same timescales or temperatures).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JdCUk.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JdCUk.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2017-05-28T08:48:45.697" LastActivityDate="2017-06-23T15:15:17.887" Title="Are there gases from the Earth useful to generate electricity besides &quot;natural gas&quot;?" Tags="|gas|fossil-fuel|" AnswerCount="5" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10478" PostTypeId="1" AcceptedAnswerId="10488" CreationDate="2017-05-28T07:08:44.910" Score="6" ViewCount="2054" Body="&lt;p&gt;I snapped this photo with my phone flat against the window of a bus, facing south while traveling west across a bridge in New Taipei City. I'd say it was at about 24.995N, 121.438E. It was about 14:00 local time, 28-05-2017, a cool day, roughly 20C outdoors but I don't know the temperature in the mountains. The overall bluish/greenish hue is the result of the tinting of the bus' window.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a name for this &quot;pouring clouds&quot; effect? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PC04u.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PC04u.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zTZTa.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zTZTa.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vsg4S.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vsg4S.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YGNxD.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YGNxD.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="2536" LastEditDate="2017-05-29T00:10:20.363" LastActivityDate="2017-05-29T04:15:29.437" Title="Is there a name for these &quot;pouring&quot; clouds?" Tags="|clouds|terminology|humidity|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10479" PostTypeId="2" ParentId="10476" CreationDate="2017-05-28T08:56:30.127" Score="8" Body="&lt;p&gt;The category &quot;other gases&quot; may not solely include other naturally occurring gases extracted from the Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you state &lt;a href=&quot;https://en.wikipedia.org/wiki/Natural_gas&quot; rel=&quot;noreferrer&quot;&gt;natural gas&lt;/a&gt; is predominantly methane, extracted from the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another type of gas commonly used is &lt;a href=&quot;https://en.wikipedia.org/wiki/Liquefied_petroleum_gas&quot; rel=&quot;noreferrer&quot;&gt;petroleum gas&lt;/a&gt;, which is prepared by refining petroleum of wet natural gas. Petroleum gas is &lt;a href=&quot;https://en.wikipedia.org/wiki/Propane&quot; rel=&quot;noreferrer&quot;&gt;propane&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Butane&quot; rel=&quot;noreferrer&quot;&gt;butane&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Coal_gas&quot; rel=&quot;noreferrer&quot;&gt;Coal gas&lt;/a&gt;, which was manufactured from coal and largely consists of hydrogen, carbon monoxide and methane, is no longer manufactured or used.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another type of gas that could be included in the category is &lt;a href=&quot;https://en.wikipedia.org/wiki/Biogas&quot; rel=&quot;noreferrer&quot;&gt;biogas&lt;/a&gt;, which is a manufactured gas made from biological waste products, such as: manure, sewage, food waste and green waste. Biogas is predominantly methane.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-05-28T08:56:30.127" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10480" PostTypeId="5" CreationDate="2017-05-28T09:45:24.910" Score="0" Body="&lt;p&gt;Geoengineering is an intervention in Earth’s systems, especially climate, with the aim to mitigate the human impact. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Proposed strategies include removal of carbon dioxide from the atmosphere and control of weather systems. The topic is of political and ethical concern. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is very few successful application of large-scale geoengineering, and the expectations are often higher than the actual outcome. Moreover, the field is spelled with conspiracy theories and humbug that might be difficult to detect for the inexperienced. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-05-28T09:51:05.797" LastActivityDate="2017-05-28T09:51:05.797" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10481" PostTypeId="4" CreationDate="2017-05-28T09:45:24.910" Score="0" Body="Intervention in Earth’s systems, especially climate, with the aim to mitigate the human impact. " OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-05-28T09:45:24.910" LastActivityDate="2017-05-28T09:45:24.910" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10483" PostTypeId="2" ParentId="10478" CreationDate="2017-05-28T12:02:58.767" Score="2" Body="&lt;p&gt;Effect like this may be caused by temperature inversion. When warm air/cloud runs into barrier like a hill or mountain it raises (convection) and temperature drops (adiabatic change). Then you see an effect like this &quot;pouring cloud&quot;. When it comes down it may cause smog when city is polluted.&lt;/p&gt;&#xA;" OwnerUserId="4610" LastActivityDate="2017-05-28T12:02:58.767" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10484" PostTypeId="2" ParentId="10476" CreationDate="2017-05-28T13:29:30.507" Score="6" Body="&lt;p&gt;Fred's answer looks correct, but in this case, the source is right there under the chart.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.eia.gov/&quot; rel=&quot;noreferrer&quot;&gt;US Energy Information Administration&lt;/a&gt;  (type &quot;other gases&quot; in the search box)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.eia.gov/electricity/annual/html/epa_03_01_a.html&quot; rel=&quot;noreferrer&quot;&gt;Explained here in the footnotes&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Other Gas includes blast furnace gas and other manufactured and waste&#xA;  gases derived from fossil fuels.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.eia.gov/tools/faqs/faq.php?id=427&amp;amp;t=3&quot; rel=&quot;noreferrer&quot;&gt;0.3% if anyone is interested&lt;/a&gt;.   Prior to 2011 the definition of other gases was different.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2017-05-28T13:29:30.507" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10485" PostTypeId="2" ParentId="10478" CreationDate="2017-05-28T14:12:51.550" Score="2" Body="&lt;p&gt;The term you are looking for is &lt;a href=&quot;http://www.atmos.washington.edu/Atlas/oro.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;orographic clouds&lt;/a&gt;.&#xA;specifically the föhn wall type created by föhn winds. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="239" LastEditDate="2017-05-28T16:24:28.257" LastActivityDate="2017-05-28T16:24:28.257" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10487" PostTypeId="2" ParentId="10472" CreationDate="2017-05-28T23:39:31.980" Score="0" Body="&lt;p&gt;In the geologic sense of the word, rocks or stones are made up predominantly of inorganic minerals. There certainly are rocks like some limestones that contain a large proportion of biogeochemically produced minerals like shells or later alteration of the original biological material. Some rocks may contain some organic matter but it often doesn't survive the process of compacting and lithifying (turning into rock).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, from the Wiki page, it sounds like gall stones are dominantly organic matter like cholesterol that may contain some inorganic material like calcium phosphate or calcium carbonate. So I wouldn't really consider them stone in the sense used in earth science but maybe there could be some gall stones that get trapped in sediments after a person dies and then turn into a tiny proportion of a sedimentary rock.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastEditorUserId="1242" LastEditDate="2017-05-29T01:34:37.397" LastActivityDate="2017-05-29T01:34:37.397" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10488" PostTypeId="2" ParentId="10478" CreationDate="2017-05-29T04:15:29.437" Score="3" Body="&lt;p&gt;The term used by the American Meteorological Society is &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Orographic_fog&quot; rel=&quot;nofollow noreferrer&quot;&gt;orographic fog&lt;/a&gt;. A perhaps more descriptive name is &quot;orographic waterfall cloud&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Prevailing winds can force air to flow upwards over rising terrain. The rising air cools more or less adiabatically, and this can in turn result in clouds. The nature of the orographic clouds (orographic: &quot;related to mountains&quot;) that result vary greatly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In arid regions, orographic clouds can form lenticular clouds that look &lt;a href=&quot;https://apod.nasa.gov/apod/ap121104.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;amazingly&lt;/a&gt; &lt;a href=&quot;https://apod.nasa.gov/apod/ap030326.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;like&lt;/a&gt; &lt;a href=&quot;https://apod.nasa.gov/apod/ap150302.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;UFOs&lt;/a&gt; (three links). Unstable conditions can result in wave clouds, where an obstruction causes a cloud after cloud after cloud downwind of the obstruction. Even &lt;a href=&quot;https://earthobservatory.nasa.gov/Features/CloudsGallery/images/sgeorgia_tmo_2015331_lrg.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;icebergs can cause wave clouds&lt;/a&gt;. Another form of orographic cloud is a banner cloud, where a cloud flies like a banner downwind of a mountain:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AbOMD.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AbOMD.jpg&quot; alt=&quot;Banner cloud flying behind the Matterhorn&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Banner_clouds.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://commons.wikimedia.org/wiki/File:Banner_clouds.jpg&lt;/a&gt; . Copyright Zacharie Grossen, license CC BY-SA 3.0&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is getting closer to an orographic fog. Climbers on the Matterhorn oftentimes experience that cloud, firsthand. Even closer to home is Table Mountain near Cape Town, South Africa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Xmq32.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Xmq32.jpg&quot; alt=&quot;Table Mountain, with a table cloth cloud descending from it&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Cape_Town,_Table_Mountain,_Table_Cloth.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://commons.wikimedia.org/wiki/File:Cape_Town,_Table_Mountain,_Table_Cloth.jpg&lt;/a&gt;. Copyright KodachromeFan, license CC BY-SA 3.0&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is an orographic fog. (Table Mountain can also create some rather spectacular lenticular clouds.) Another example of an orographic fog is detailed in the article &quot;&lt;a href=&quot;http://www.hko.gov.hk/education/article_e.htm?title=ele_00484&quot; rel=&quot;nofollow noreferrer&quot;&gt;Waterfall-like Orographic Clouds&lt;/a&gt;&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The conditions needed to form an orographic fog include&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Prevailing winds that force air to blow upwards over an obstruction, with the orographic fog flowing downwind from the obstruction.&lt;/li&gt;&#xA;&lt;li&gt;The flowing air must be sufficiently humid. Without this condition, you might see a very cool looking lenticular cloud, but you won't see a banner cloud or an orographic fog.&lt;/li&gt;&#xA;&lt;li&gt;The flowing air must be sufficiently cool. Humid air at the same pressure and temperature of arid air is less dense than is that arid air. The flowing humid air has to be fairly cool for the flow to be downward downwind of the obstruction.&lt;/li&gt;&#xA;&lt;li&gt;The flow has to be fairly slow (low Reynolds number) and uniform (low Froude number). Otherwise, a wave cloud or banner cloud will result.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-05-29T04:15:29.437" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10493" PostTypeId="1" AcceptedAnswerId="23170" CreationDate="2017-05-30T12:32:57.087" Score="11" ViewCount="522" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/v1yNZ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/v1yNZ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aMcW8.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aMcW8.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;above x2:&lt;/strong&gt; Photos by David Finlay, from &lt;a href=&quot;http://www.bbc.com/news/world-australia-39728714&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The BBC news article &lt;a href=&quot;http://www.bbc.com/news/world-australia-39728714&quot; rel=&quot;noreferrer&quot;&gt;Rare 'sprites' photographed beside Southern Lights&lt;/a&gt; shows photographs by the Australian photographer David Finlay. They are remarkably clear and distinct, and set against a clear night sky filled with stars. (The two fuzzy blue blobs are the large and small &lt;a href=&quot;https://en.wikipedia.org/wiki/Magellanic_Clouds&quot; rel=&quot;noreferrer&quot;&gt;Magellanic Clouds&lt;/a&gt; - dwarf galaxies in the local group.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I had thought that sprites were challenging to photograph not only because they are dim and rare requiring a special low-light cooled-CCD camera and luck, but that one had to be almost directly above a thunderstorm. This is a view of an almost completely clear sky, from the ground with a normal camera.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are the clouds and light in the distance at the bottom of the first image the source of these sprites? There is really that much difference in altitude between the sprite and the associated thunderstorm?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2021-11-18T03:28:40.893" Title="Photo of sprites in a clear dark sky, how is this possible?" Tags="|lightning|thunderstorm|upper-atmosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10494" PostTypeId="1" CreationDate="2017-05-30T18:28:02.737" Score="4" ViewCount="2476" Body="&lt;p&gt;I want to calculate vertically integrated moisture flux convergence (VIMFC) in &lt;a href=&quot;http://cola.gmu.edu/grads/&quot; rel=&quot;nofollow noreferrer&quot;&gt;GrADS&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But when I give the following instruction it marks me errors:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;sdfopen shum.mon.mean.nc&#xA;sdfopen uwind.mon.mean.nc&#xA;sdfopen vwind.mon.mean.nc&#xA;&#xA;set lon 180 320&#xA;set lat 0 60&#xA;set t 763 766&#xA;set lev 1000 300&#xA;&#xA;qu=vint(1000,shu,.1*uwnd.2,300)&#xA;qv=vint(1000,shu,.1*vwnd.3,300)&#xA;&#xA;vimf=-hdivg(qu,qv)&#xA;d vimf&#xA;&#xA;ga-&amp;gt; qu=vint(1000, shum.1*uwnd.2,600)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Error from VINT:  &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Incompatible grids.&#xA;*** glibc detected *** grads: double free or corruption (!prev): 0x0000000003707c40 ***&#xA;======= Backtrace: =========&#xA;/lib/x86_64-linux-gnu/libc.so.&#xA;&#xA;6(+0x7e846)[0x7f898ac4c846]&#xA;grads(gree+0x2bb)[0x4fab92]&#xA;grads(gadef+0x126b)[0x518144]&#xA;grads(gacmd+0x16c)[0x52af24]&#xA;grads(main+0xa7a)[0x4975ab]&#xA;/lib/x86_64-linux-gnu/libc.so.6(__libc_start_main+0xed)[0x7f898abef76d]&#xA;grads[0x4960a9]&#xA;======= Memory map: ========&#xA;00400000-00bcb000 r-xp 00000000 08:05 1573111&#xA;7f898bdc2000-7f898bdc3000 r--p 00017000 08:05 1572886                    /lib/x86_64-linux-gnu/libpthread-2.15.soAborted (core dumped)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Does anyone know how to fix it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Best,&#xA;Pablo Camarena&lt;/p&gt;&#xA;" OwnerUserId="8259" LastEditorUserId="543" LastEditDate="2017-05-31T02:28:54.000" LastActivityDate="2022-01-14T07:07:41.050" Title="Moisture flux convergence in GrADS" Tags="|meteorology|models|software|moisture-flux|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10495" PostTypeId="1" AcceptedAnswerId="10496" CreationDate="2017-05-30T21:29:37.227" Score="4" ViewCount="173" Body="&lt;p&gt;I have some data (GRIB layers) about wind components u and v, which I would like to use to estimate wind magnitude and direction. But the model says it is for 10 m altitude. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a way to extrapolate this value for higher altitudes? lets say 600 m. If yes, how? which other variables should I consider that can bias this calculation?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks a lot!&lt;/p&gt;&#xA;" OwnerUserId="7256" LastActivityDate="2017-05-31T14:01:02.377" Title="Can we extrapolate wind speed data to higher altitudes?" Tags="|meteorology|wind|air-currents|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10496" PostTypeId="2" ParentId="10495" CreationDate="2017-05-30T22:55:18.907" Score="7" Body="&lt;p&gt;Yes, but it may not be valid. The extrapolation will be valid for about 0.1 * &lt;a href=&quot;http://elte.prompt.hu/sites/default/files/tananyagok/AtmosphericChemistry/ch01s05.html&quot; rel=&quot;noreferrer&quot;&gt;PBL&lt;/a&gt; Height using the &lt;a href=&quot;https://en.wikipedia.org/wiki/Log_wind_profile&quot; rel=&quot;noreferrer&quot;&gt;Log-Wind&lt;/a&gt; Profile &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You will need:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;PBL Height.&lt;/li&gt;&#xA;&lt;li&gt;A second Wind speed (within 0.1*PBL Height)&lt;/li&gt;&#xA;&lt;li&gt;Surface Sensible Heat Flux&lt;/li&gt;&#xA;&lt;li&gt;Surface Latent Heat Flux&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.shodor.org/os411/courses/_master/tools/calculators/pottemp/pt1calc.html&quot; rel=&quot;noreferrer&quot;&gt;Potential Temperature&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;You can use the last three variables to calculate the &lt;a href=&quot;https://en.wikipedia.org/wiki/Monin%E2%80%93Obukhov_length&quot; rel=&quot;noreferrer&quot;&gt;Monin-Obukhov Length (MOL)&lt;/a&gt;. Then use the MOL to calculate $\psi$:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If L&gt;0 $\psi=\frac{z}{L}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If L=0 $\psi=0$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If L&amp;lt;0 $\psi=2\ln(\frac{1+x}{2})+\ln(\frac{1+x^2}{2})-2\tan^{-1}(x)+\frac{\pi}{2}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $x=(1-15\frac{z}{L})^{\frac{1}{4}}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now that you have $\psi$, you can derive the friction velocity and surface roughness length using the log-wind profile  and $\psi(\frac{z}{L})$. Once you have those two, you can extrapolate wind speed 600 meters up, provided the surface layer is that high.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="6298" LastEditDate="2017-05-31T14:01:02.377" LastActivityDate="2017-05-31T14:01:02.377" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10500" PostTypeId="1" CreationDate="2017-05-31T20:23:21.447" Score="1" ViewCount="445" Body="&lt;p&gt;Oregon lake has a drain hole at the bottom but also has water flowing into it. Pingualuit crater has no water flowing into it but probably has no drain hole at the bottom either. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm wondering if there's also a lake that has no water flowing into it but has a drain hole at the bottom. If such a lake exists, would the water in it be very pure because the slightest bit of impurities in it move to the drain hole and flow out? I think that for such a lake to exist, the land around it would have to be higher than the land further away like Pingualuit crater.&lt;/p&gt;&#xA;" OwnerUserId="4846" LastEditorUserId="2536" LastEditDate="2017-06-01T05:22:12.533" LastActivityDate="2017-06-01T05:22:12.533" Title="Is there a lake whose sole source of water is rain and has a hole at the bottom draining it?" Tags="|water|lakes|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10501" PostTypeId="2" ParentId="10500" CreationDate="2017-06-01T05:20:39.563" Score="7" Body="&lt;p&gt;I think there is some misunderstanding of the water balance of a lake, or to put it differently, why some holes in the ground are dry while some are filled with water (known as lakes). The linked articles contain lists of &lt;a href=&quot;https://en.wikipedia.org/wiki/Endorheic_basin&quot; rel=&quot;noreferrer&quot;&gt;closed lakes&lt;/a&gt;, but I'll also try to explain how lakes are formed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fresh water comes from the rainfall (and snow and &lt;a href=&quot;https://en.wikipedia.org/wiki/Dew&quot; rel=&quot;noreferrer&quot;&gt;moisture&lt;/a&gt;) that falls on the ground, and if it does not evaporate, it will eventually seep down into the &lt;a href=&quot;http://www.groundwater.org/get-informed/basics/groundwater.html&quot; rel=&quot;noreferrer&quot;&gt;groundwater&lt;/a&gt; when it reaches the &lt;em&gt;groundwater table&lt;/em&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The groundwater flows towards lower elevation, known as &lt;em&gt;hydrostatic head&lt;/em&gt;, and eventually, it reaches the sea level. If you would dig a number of holes from the sea towards the mountains, you'll see that if the holes are deep enough to reach groundwater (wells), the elevation of the groundwater surface will form a slope. If the geology is such that the water only flows slowly through the ground and the precipitation is high, the slope can be steep, but if you have e.g. a sandy ground and low precipitation, the groundwater table is subhorizontal. Indeed, in areas with high evaporation, the slope can face away from the ocean, towards a local depression as e.g. the Dead Sea or Death Valley.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the groundwater table crosses the ground so that the elevation of ground is lower than the hydrostatic pressure of the groundwater, the groundwater will be exposed and form a lake or enter a river. The lakes and rivers are manifestations of the groundwater level. Sometimes there is a delayed response time as water flows much quicker in a river than in the ground. This causes flash floods to flow above the ground if there is not enough time for surface water to penetrate the surface. Like a coffee filter overflooding if one pour water in it too fast. Given enough time, the surface water will enter the groundwater and flow towards the ocean or evaporate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sometimes there are features that speed up the flow, e.g. karsts or gravel lenses that have a very high &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydraulic_conductivity&quot; rel=&quot;noreferrer&quot;&gt;hydraulic conductivity&lt;/a&gt; so that water can flow rather fast through. Interesting phenomena can occur that control this kind of quick drains if e.g. the drainage gets frozen and clogged in winter or there are some other seasonal variations. This is maybe what you describe as a drain hole, but usually, lakes without outlets just adjust the water back into the groundwater by &lt;a href=&quot;https://en.wikipedia.org/wiki/Standard_penetration_test&quot; rel=&quot;noreferrer&quot;&gt;penetration&lt;/a&gt; and by evaporation of the surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Dissolved salt is concentrated in lakes without an outlet and they are called &lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Endorheic_basin&quot; rel=&quot;noreferrer&quot;&gt;closed lakes&lt;/a&gt;&lt;/em&gt; or &lt;em&gt;endorheic basin&lt;/em&gt;. If the climate is changing, an open lake can become a closed lake and vice versa. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A lake is always a temporary feature. They fill up with sediments over time and becomes a part of the river path. As you noticed, there is always a special reason for a lake to form, e.g. rapid post-glacial rebound, rifting or an impact crater. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ponds and &lt;a href=&quot;https://en.wikipedia.org/wiki/Tarn_(lake)&quot; rel=&quot;noreferrer&quot;&gt;tarns&lt;/a&gt; without a visible outlet are rather common, at least in post-glacial areas as Canada or Scandinavia, but if a lake has enough inflow, its level will rise until it gets a visible outlet. Depressions without a visible outlet are called &lt;a href=&quot;https://en.wikipedia.org/wiki/Sink_(geography)&quot; rel=&quot;noreferrer&quot;&gt;sinks&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How pure the water in the lake is depends on a number of factors. Silt and clay come from fast-flowing inlet rivers or wind. The residual time and current for the water in the lake defines how much of the sediments that have time to settle. The bathymetry is also an important factor as local depocenters can take care of most of the sediments. Fine sediments can take a long time to settle. Finally, the biology of the lake is naturally very important. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastActivityDate="2017-06-01T05:20:39.563" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10503" PostTypeId="1" AcceptedAnswerId="10507" CreationDate="2017-06-01T16:44:12.157" Score="6" ViewCount="3705" Body="&lt;p&gt;Excuse my ignorance. I'm under the impression that there are various types of ice at the poles, but I don't know the difference or the significance of each type, so, in terms of whatever is actually melting in these areas as a result of climate change, is it possible that it could come back if greenhouse gas emissions were eliminated or something like that? Basically, I'm assuming that the ice caps are necessary in order to maintain the habitability of the planet for humans, so is there some sort of threshold of melting that would essentially count as a point of no return or is there always the possibility of seeing the ice caps return to safe levels?&lt;/p&gt;&#xA;" OwnerUserId="8281" LastEditorUserId="11908" LastEditDate="2019-03-13T05:10:48.690" LastActivityDate="2024-02-24T04:08:38.220" Title="Can ice caps reform if they disappear?" Tags="|climate-change|glaciology|ice-sheets|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10504" PostTypeId="2" ParentId="10503" CreationDate="2017-06-01T21:07:56.027" Score="2" Body="&lt;p&gt;Yes they can reform even if completely melted and they done this have in the geologic past, you just need to get the planet cool enough again. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You only need two things for ice caps on earth, continents in the right place (near the poles) and a low enough temprature. The current antarctic ice caps formed about 34 million years ago. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2017-06-02T03:32:18.660" LastActivityDate="2017-06-02T03:32:18.660" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10505" PostTypeId="1" CreationDate="2017-06-01T21:21:40.513" Score="3" ViewCount="62" Body="&lt;p&gt;Near pumping wells or near/beneath a stream, the groundwater flow is not totally horizontal and the vertical component of groundwater movement at these points cannot be ignored in reality. Often, groundwater flow equations are derived while assuming that the flow in largely horizontal which is called Duipuit-Forscheimer assumption. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to know if we consider the vertical flow near pumping wells and streams, what form will the groundwater flow equations have?&lt;/p&gt;&#xA;" OwnerUserId="5557" LastEditorUserId="2536" LastEditDate="2017-06-03T05:08:23.007" LastActivityDate="2017-07-27T11:57:27.267" Title="What forms do groundwater flow equations have when Dupuit supposition is not considered?" Tags="|hydrology|groundwater|hydrogeology|fluid-dynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10506" PostTypeId="1" AcceptedAnswerId="10510" CreationDate="2017-06-01T21:59:31.813" Score="13" ViewCount="481" Body="&lt;p&gt;Looks like it has something to do with fishing: &lt;a href=&quot;https://www.google.com/maps/place/9%C2%B032&amp;#39;00.9%22N+138%C2%B011&amp;#39;20.8%22E/@9.5339863,138.1891537,543m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d9.5335853!4d138.1890973&quot; rel=&quot;noreferrer&quot;&gt;Google maps link&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GhRS1.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GhRS1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8283" LastEditorUserId="2536" LastEditDate="2017-06-02T03:57:20.323" LastActivityDate="2017-06-02T03:57:20.323" Title="What are those arrowlike underwater structures for?" Tags="|human-influence|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10507" PostTypeId="2" ParentId="10503" CreationDate="2017-06-01T23:34:11.560" Score="9" Body="&lt;p&gt;Yes, polar ice can melt -- significantly, if not completely, with substantial effects on human civilization. And it can stabilize and recover, but the question is at what pace relative to human civilization.&lt;/p&gt;&#xA;&lt;p&gt;There are generally three types of polar ice:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Ice sheets: &amp;quot;&lt;a href=&quot;https://nsidc.org/cryosphere/quickfacts/icesheets.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;An ice sheet is a mass of glacial land ice extending more than 50,000 square kilometers (20,000 square miles). The two ice sheets on Earth today cover most of Greenland and Antarctica.&lt;/a&gt;&amp;quot;&lt;/li&gt;&#xA;&lt;li&gt;Ice shelves: &amp;quot;&lt;a href=&quot;https://nsidc.org/cryosphere/quickfacts/iceshelves.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Permanent floating sheets of ice that connect to a landmass.&lt;/a&gt;&amp;quot;&lt;/li&gt;&#xA;&lt;li&gt;Sea ice: &amp;quot;&lt;a href=&quot;https://nsidc.org/cryosphere/quickfacts/seaice.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sea ice is frozen ocean water. It forms, grows, and melts in the ocean. In contrast, icebergs, glaciers, and ice shelves float in the ocean but originate on land.&lt;/a&gt;&amp;quot;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Sea ice is usually 1-2 meters thick; shelf ice is 100-200 meters thick; sheet ice is one to several kilometers thick.&lt;/p&gt;&#xA;&lt;p&gt;The poles differ significantly. It's often pointed out that the Arctic is an ocean surrounded by land and the Antarctic is land surrounded by ocean. The North Pole is occupied by sea ice, about half of which melts every summer and reforms every winter.&lt;/p&gt;&#xA;&lt;p&gt;At the other extreme are the ice &amp;quot;caps,&amp;quot; more or less the ice sheets in Greenland and Antarctica that extrude ice in the form of glaciers and ice shelves that continuously flow into the ocean, breaking apart and melting.&lt;/p&gt;&#xA;&lt;p&gt;To take just Greenland: &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0277379110000399&quot; rel=&quot;nofollow noreferrer&quot;&gt;Greenland has had some degree of glaciation for ~38 million years,&lt;/a&gt; but lost much or almost all of its ice during a warming period about 400,000 years ago, suggesting that the current ice sheet was created in that time.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The evidence suggests nearly total ice-sheet loss may result from&#xA;warming of more than a few degrees above mean 20th century values, but&#xA;this threshold is poorly defined (perhaps as little as 2 °C or more&#xA;than 7 °C).]&lt;a href=&quot;http://www.annualreviews.org/doi/10.1146/annurev-earth-060614-105344&quot; rel=&quot;nofollow noreferrer&quot;&gt;5&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;(That melt ice is equivalent to about 7.3 meters of global sea level rise.)&lt;/p&gt;&#xA;&lt;p&gt;So, yes, the ice sheets can melt away; how quickly they can melt will be driven by the amount and pace of CO2 emissions; the extent of that melting will be affected by the duration of that CO2 in the atmosphere and the impact of potential feedbacks.&lt;/p&gt;&#xA;&lt;p&gt;The formation of an ice sheet -- glaciation -- can occur relatively rapidly in the correct conditions, according to &lt;a href=&quot;http://www.ipcc.ch/pdf/assessment-report/ar4/wg1/ar4-wg1-chapter6.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this IPCC Assessment report on paleoclimate&lt;/a&gt;, which notes glaciation occurring in some regions of the world within a period of centuries.&lt;/p&gt;&#xA;&lt;p&gt;In the short term, the most obvious impact we're seeing from global warming is the steady decline in the extent of Arctic Sea ice, &lt;a href=&quot;http://nsidc.org/arcticseaicenews/&quot; rel=&quot;nofollow noreferrer&quot;&gt;at about 2.6 percent per decade since the satellite record began in 1979&lt;/a&gt;. &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2011GL048739/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;Research suggests that this ice can come back, eventually&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The central finding of this study is that sea ice loss is fully&#xA;reversible in a state-of-the-art GCM over a range of CO2&#xA;concentrations from the 1990s level to nine times higher. We find no&#xA;evidence for threshold behavior in the summer or winter ice cover in&#xA;either hemisphere. Thus if tipping points exist for future sea ice&#xA;retreat in nature, it is for subtle reasons, i.e., through processes&#xA;that are absent or inadequately represented in this model.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;However, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2016EF000410/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;this team of researchers&lt;/a&gt; suggested an extensive project to prevent a worst-case scenario:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This loss of sea ice represents one of the most severe positive&#xA;feedbacks in the climate system, as sunlight that would otherwise be&#xA;reflected by sea ice is absorbed by open ocean. It is unlikely that&#xA;CO2 levels and mean temperatures can be decreased in time to prevent&#xA;this loss, so restoring sea ice artificially is an imperative. Here we&#xA;investigate a means for enhancing Arctic sea ice production by using&#xA;wind power during the Arctic winter to pump water to the surface,&#xA;where it will freeze more rapidly.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7314" LastEditorUserId="30533" LastEditDate="2024-02-24T04:08:38.220" LastActivityDate="2024-02-24T04:08:38.220" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="10508" PostTypeId="1" CreationDate="2017-06-02T00:40:36.480" Score="1" ViewCount="174" Body="&lt;p&gt;Usually, when data is collected in an experiment, scientists have a control. Experiments are seen as flawed without controls. I am just curious as to where else scientists have 'built' controls using models. Obviously, we cannot find a real 'control Earth', so we must make climate models, but then why can we even proceed with the experiment (how are we so sure the models act within a small error of the 'control Earth')?  &lt;/p&gt;&#xA;" OwnerUserId="8284" LastEditorUserId="20" LastEditDate="2019-12-21T07:44:56.423" LastActivityDate="2019-12-21T07:44:56.423" Title="Why is it good scientific practice to 'build' a 'control Earth' from models, and where else do we 'build' controls?" Tags="|climate|climate-change|human-influence|" AnswerCount="2" CommentCount="4" ClosedDate="2019-12-21T10:21:58.580" ContentLicense="CC BY-SA 3.0" />
  <row Id="10509" PostTypeId="2" ParentId="10506" CreationDate="2017-06-02T03:41:31.823" Score="9" Body="&lt;p&gt;They look like stone fish traps or &lt;a href=&quot;https://en.wikipedia.org/wiki/Fishing_weir&quot; rel=&quot;noreferrer&quot;&gt;weirs&lt;/a&gt;. They are used by native poeple to catch fish on a large scale.  They can actually vary quite a bit by culture and can be quite large.  Here is a stone and wood one with the same shape&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LLFtr.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LLFtr.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2017-06-02T03:41:31.823" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10510" PostTypeId="2" ParentId="10506" CreationDate="2017-06-02T03:52:06.113" Score="14" Body="&lt;p&gt;Those are Yap Traditional Fish Weirs, according to &lt;a href=&quot;http://www.islandculture.info/yaptraditionalfishweirs/index.htm&quot; rel=&quot;noreferrer&quot;&gt;islandculture.info&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In 2008, Yap State Historic Preservation Office (YSHPO) commenced a&#xA;  project to survey the fish weirs (aech) around the main island of Yap.&#xA;  The aech is a stone/rock structure, usually in the shape of an arrow&#xA;  (many have a shaft, some do not), that catch fish after they move&#xA;  inside a catchment area at high tide and are trapped when the tide&#xA;  goes out. It is thought 700-800 aech may be located around Yap's main&#xA;  island which has a coastline of about 100 km in circumference.&#xA;  &lt;a href=&quot;https://i.stack.imgur.com/MSeDA.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MSeDA.jpg&quot; alt=&quot;Yap traditional fish weirs&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2017-06-02T03:52:06.113" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10511" PostTypeId="1" CreationDate="2017-06-02T06:37:08.130" Score="5" ViewCount="3475" Body="&lt;p&gt;Nikolov &amp;amp; Zeller have published a paper concerning what they call The Unified Theory of Climate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.omicsonline.org/open-access/New-Insights-on-the-Physical-Nature-of-the-Atmospheric-Greenhouse-Effect-Deduced-from-an-Empirical-Planetary-Temperature-Model.pdf&quot; rel=&quot;noreferrer&quot;&gt;https://www.omicsonline.org/open-access/New-Insights-on-the-Physical-Nature-of-the-Atmospheric-Greenhouse-Effect-Deduced-from-an-Empirical-Planetary-Temperature-Model.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please read the paper in full and then answer my question. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Personally I can see no areas in which the new theory is compatible with the current theory of the Greenhouse Gas Effect and Anthropogenic Global Warming however there are some extremely knowledgeable participants on this site so I welcome their input but only, please, if you have read the whole paper.  &lt;/p&gt;&#xA;" OwnerUserId="7733" LastActivityDate="2018-11-20T16:00:22.447" Title="Is the Unified Theory of Climate (Nikolov &amp; Zeller) compatible with the AGW/GHG theory in any respect?" Tags="|atmosphere|climate|climate-change|" AnswerCount="3" CommentCount="19" ContentLicense="CC BY-SA 3.0" />
  <row Id="10512" PostTypeId="2" ParentId="10503" CreationDate="2017-06-02T08:11:12.873" Score="2" Body="&lt;p&gt;Ice caps are not essential for the planet to be habitable - over geological history, they are usually absent. Melting them would inconvenience many humans, though - there is a good calculator of this &lt;a href=&quot;http://www.floodmap.net/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Jeffronicus has answered most of this, but as a direct answer to part of the question, the &lt;a href=&quot;http://www.nature.com/nclimate/journal/v2/n6/full/nclimate1449.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Greenland Ice Sheet&lt;/a&gt; may be metastable - as in, if you magically removed it today, it would not regrow unless the climate was significantly cooler.  The West Antarctic Ice Sheet is probably already destabilized - it is grounded below sea level, so once it starts to go it's unstoppable - but again it could grow back.&lt;/p&gt;&#xA;" OwnerUserId="8217" LastActivityDate="2017-06-02T08:11:12.873" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10513" PostTypeId="2" ParentId="10511" CreationDate="2017-06-02T13:24:22.017" Score="19" Body="&lt;p&gt;The paper you linked lists as its first reference &lt;a href=&quot;https://springerplus.springeropen.com/articles/10.1186/2193-1801-3-723&quot; rel=&quot;noreferrer&quot;&gt;Volokin and ReLlez, 2014&lt;/a&gt;; a paper that addresses the magnitude of the Earth's greenhouse effect. The validity of the paper you found largely hinges on the reputation of the Volokin and ReLlez, so we will investigate that one first. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;The science of Volokin and ReLlez&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The traditional way to determine the 'greenhouse effect' of a planet is to compare actual planetary temperatures with Stefan-Boltzmann blackbody temperature based on the luminosity of the star, distance from star, and the albedo and emissivity of the planet. This calculation is done in Volokin and ReLlez and can also be found on &lt;a href=&quot;https://en.wikipedia.org/wiki/Effective_temperature#Surface_temperature_of_a_planet&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Volokin and ReLlez are arguing that the actual greenhouse effect should be measured using the albedo of a bare planet stripped of its clouds. The Earth's albedo is 0.294, but they propose a bare albedo of the Earth of between 0.122 and 0.13. They then make an argument that simple albedo calculations are not very accurate, and that a use of Holder's Inequality should be used to integrate the effects of albedo and radiation incidence angle over the exposed surface of the bare planet. Redoing the Stefan-Boltzmann expected temperature calculations with this new method, they then calculate that actual 'greenhouse effect' of the Earth is more like 90 K, instead of the 33 K normally cited. This is significant because temperature magnitude of the Earth's greenhouse effect affects the climate sensitivity factor of global warming models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I actually think this paper is pretty interesting. The core of its mathematical arguments seems valid (though I didn't try to work any of it out myself) However, the conclusions are not very good, and not very related to much of the mathematical arguments in the body. While there is an argument to be made that calculating expected surface temperature should assume a bare planet, the authors are basically concluding that &lt;em&gt;all&lt;/em&gt; temperature differences between the bare planet and the observed Earth should be assigned to the greenhouse effect. That just isn't supported by the information they present. The Earth's actual atmosphere and biosphere are much more dynamic than the bare model they are presenting; the formation of high-albedo clouds by equatorial rainforests,and the presence of high-albedo sand in the sunniest places on Earth are just two non-greenhouse related effects that account for temperature differences between the author's ideal bare Earth and the real Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;While they consider a lot of interesting factors, I think Volokin and ReLlez are guilty of making too much of a spherical cow estimate. The author's make an argument for one thing, then make some huge leaps to an unsupported conclusion. All in all, I don't think that the author's conclusion of a 90 K greenhouse effect is valid.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;The publication of the reference&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Whatever its scientific merits, the paper doesn't look very good upon meta review. First off, the authors used fake names to publish the paper in an open access site. In fact, it is the same two authors of the paper you linked, except that they spelled their names backwards (Nikolov -&gt; Volokin; Zeller -&gt; ReLlez). Ummm...what? Also, they later &lt;a href=&quot;http://retractionwatch.com/2016/09/13/u-s-govt-researchers-withdraw-climate-paper-after-using-pseudonyms/&quot; rel=&quot;noreferrer&quot;&gt;retracted the paper&lt;/a&gt;. Also also, the journal they published in &lt;a href=&quot;https://springerplus.springeropen.com/&quot; rel=&quot;noreferrer&quot;&gt;is now defunct&lt;/a&gt;. All in all, this is not a sign that the paper is good science. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Back to the original paper&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;So the paper that you are asking about (Nikolov and Zeller, 2017) is based on a paper by the same authors which has not-very-good conclusions, and was generally published in a shady manner. That's a big black mark at the very outset. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This paper is pretty long and detailed, and I admit I did not read all of it. But the kill shot for me was on the very first page:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We  began  our  study  with  the  premise  that  processes &#xA;  controlling   the  Global  Mean  Annual  near-surface  Temperature &#xA;  (GMAT)  of  Earth   are  also  responsible  for  creating  the &#xA;  observed  pattern  of  planetary   temperatures across the Solar&#xA;  System. Thus, our working hypothesis was  that  a  general  physical &#xA;  model  should  exist,  which  accurately  describes   equilibrium &#xA;  GMATs  of  planets  using  a  common  set  of  drivers.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That is great, but we have already gone over how these authors are attempting to oversimplify a bare planet approach for predicting expected temperatures. The predictor variables they are using are stellar irradiance, blackbody reference temperature, greenhouse gas partial pressure and density, atmospheric pressure and density, and reference pressure for greenhouse fluids. We can see the authors are once again ignoring the effects of cloud formation and the way the biosphere affects albedo, amongst other things.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On a methodology note, the authors use a regression model to try to get some useful results. As a statistician (not a planetary scientist), this strikes me as a poor choice. Regression analysis of complex systems is a good way to get insight into what factors are important in affecting this system. I think they can be very useful for predicting trends, but I do not believe they are good for providing predictions that are accurate by physical science standards. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, I'm writing a paper right now that uses regression analysis to predict subway ridership at each station on a subway network. This is a very complex system (like planetary atmospheres), and our goal is to get error scores of 0.2 or so. That is great for predicting subway ridership, not so much for planetary temperatures. An error score of 0.2 is like predicting a temperature to be 300 K but it is actually 360 K. That's not good enough. So I just don't know what the authors are really trying to accomplish using a regression approach, especially with so few predictor variables. The physics behind the interaction of the predictor variables is pretty well known, so there isn't a lot of value if determining the correlations of the predictor values to the planet surface temperature; it is as if they are using the regression to test if the physics is correct. Finally, the data set is way too small to be using a regression analysis. Their only available data points are the planets and moons in our own solar system. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Conclusion&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Well I wrote a lot there, and hopefully it is all comprehensible. All in all, there are some interesting bits to Nikolov and Zeller's approach, but I think they are over simplifying some things and are using a non-physical science applicable methodology to obtain questionable conclusions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Honestly, I don't think that anyone should be treating their research pejoratively (I'm looking at you Andrew Jon Dodds in the comments). It is interesting, and it is certainly novel (from everything I've read). It just doesn't have great conclusions. And that's fine! Most research probably doesn't lead anywhere useful. At least they tried something. People seem to be mad at them just because the results are contrary to the general climate change consensus. Research should be appraised on its merits (or lack thereof) and not on whether its conclusions match preconceptions. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="6703" LastEditDate="2017-07-13T18:30:29.263" LastActivityDate="2017-07-13T18:30:29.263" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10514" PostTypeId="2" ParentId="10508" CreationDate="2017-06-02T16:52:47.440" Score="4" Body="&lt;p&gt;What do you mean by a control Earth? There is a control Earth: all of history until now. We don't know everything that happened on this control Earth, but we have some reasonable estimates of how temperature, carbon dioxide levels, and other factors changed in the past, and so we us those as best we can to develop how the Earth &lt;em&gt;did&lt;/em&gt; act.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, we have another data point to use, other than our limited information about the past Earth. We have physics to describe heat transfer, radiation emission and absorption and more. We could use this knowledge to create a model wholly independent of any knowledge of past Earth conditions. Since the various physics we use is all experimentally confirmed, we can be much more confident in it than we can in past Earth conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you build a climate model, you make sure that the things that &lt;em&gt;did&lt;/em&gt; happen can be modeled correctly by that model. The climate models that I am familiar with meet that criteria, for some subsection of the past that was used to create the model. Admittedly, the model is only as good as the past data we are using to calibrate it; but in the physics of the model we can be certain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So we have created models that can correctly predict the temperature changes in some subset of the past, and we are using those to extrapolate into the future. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2017-06-02T16:52:47.440" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10518" PostTypeId="2" ParentId="10508" CreationDate="2017-06-03T21:45:08.947" Score="6" Body="&lt;p&gt;It's true that, usually, when data is collected in an experiment scientists have a control, and very often not having a control results in a flawed experiment - that is, an experiment from which less conclusions can be drawn.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Experiments are a very efficient way to gather high quality data, but in some fields they might even be impossible. However, experiments aren't the only way to get knowledge and they aren't mandatory to make science.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In some fields experiments are quite easy and therefore most research is based in experiments. For example, it's usually easy for chemist to test the way substances react by making experiments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other fields some questions can't be resolved by direct experiments due to practical or ethical reasons. In a known textbook example, sociologists are interested in what circumstances cause suicide rates to rise or drop, but ethics prevents them from performing an experiment by submitting a sample of people to circumstances supposed to induce suicide and compare suicide rate of this sample with suicide rate in a control sample. Therefore, sociologist need to draw conclusions from observational data - that is, observing real population under natural circumstances they can't adjust - or from experiments of related phenomena that can be performed without ethical concerns.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We in Earth sciences face a similar problem: some experiments can't be done because of scale or just because we just have an only Earth. For example, how do we know that rivers cause deltas? Ideally, we'd like to do an experiment by selecting several coast tracts, putting rivers in a randomly chosen sample of them, waiting a few millions of years and comparing evolution of the coast tracts with and without rivers. We can't do this experiment, but it doesn't prevent geologists to have learned a lot about deltas, because we have a lot of data from observation of naturally occurring deltas, from small scale experiments, and from study of auxiliary sciences (physics, hydraulics, etc.).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Climate is similar to deltas. Just as we can experiment with setting and removing rivers, we can't change CO2 levels of the whole atmosphere to measure what happens, but we can observe what actually happens, search for geological register of what happened in the past, do a lot of small scale experiments, and use our knowledge of basic sciences and draw conclusions about climate evolution from them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clearly, interpretation of that data is not as straightforward as data from a big experiment would be, but it is still possible and useful. In fact, it's the way most of current knowledge in many fields has been built.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All that without needing a random sample of Earths nor a control Earth.&lt;/p&gt;&#xA;" OwnerUserId="6550" LastEditorUserId="6550" LastEditDate="2017-06-04T19:18:31.333" LastActivityDate="2017-06-04T19:18:31.333" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10519" PostTypeId="1" CreationDate="2017-06-04T03:49:58.980" Score="13" ViewCount="104" Body="&lt;p&gt;This very basic question occurred to me during a talk on reanalysis data sets. Often we know the observations produced by a particular instrument, say rain radar, are biased from one year to the next because of changes in how the instrument has been calibrated, or because methodologies for processing the raw data it produces have changed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How is this dealt with in long reanalysis data sets like ERA-Interim? Are the observational data sets made as consistent as possible before being fed into the reanalyses model, or are biases somehow smoothed out through complex data-assimilation methods or something along those lines?    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: To provide a specific example, how are scatterometer data sets incorporated into ERA-Interim when we know there are biases between them (for example &lt;a href=&quot;http://dx.doi.org/10.1007/s00343-015-4160-4&quot; rel=&quot;noreferrer&quot;&gt;Wu and Chen (2015)&lt;/a&gt;)?  &lt;/p&gt;&#xA;" OwnerUserId="4587" LastEditorUserId="6" LastEditDate="2017-06-06T10:51:26.777" LastActivityDate="2017-06-06T10:51:26.777" Title="How are scatterometer observations standardised before being fed into reanalysis models?" Tags="|meteorology|climate|climate-models|reanalysis|era|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10520" PostTypeId="5" CreationDate="2017-06-04T11:52:31.497" Score="0" Body="&lt;p&gt;Data visualization is important for all branches of Earth science. Bad visualization can confuse the message and lead to wrong interpretation. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-06-04T11:52:31.497" LastActivityDate="2017-06-04T11:52:31.497" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10521" PostTypeId="4" CreationDate="2017-06-04T11:52:31.497" Score="0" Body="Visualization concerns methods of showing data and communicate results. " OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-06-04T11:52:31.497" LastActivityDate="2017-06-04T11:52:31.497" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10522" PostTypeId="1" AcceptedAnswerId="10529" CreationDate="2017-06-04T15:31:23.313" Score="2" ViewCount="163" Body="&lt;p&gt;I have no background in climate science, but I've become interested in explanations of the so-called &quot;global warming hiatus&quot; from 1998-2013. One explanation that people seem to think is convincing comes from &lt;a href=&quot;http://science.sciencemag.org/content/348/6242/1469&quot; rel=&quot;nofollow noreferrer&quot;&gt;Karl et al&lt;/a&gt; who, if I understand correctly, say that the apparent hiatus could actually be an artifact of changes the way we calculate sea-surface temperature -- specifically that during that period we moved from primarily boat-based temperature measurements to primarily buoy and Argo float measurements. Since boat measurements are systematically a bit warmer than buoy measurements, the gradual switchover looks like a slight cooling trend when in fact it's just a difference in measurement technique.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I wanted to assess this argument for myself as well as I could, so I thought, if Karl et al are correct, then we shouldn't see evidence of hiatus in land-based datasets then, right? So I went in search of a dataset like &lt;a href=&quot;https://climate.nasa.gov/vital-signs/global-temperature/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA's global land-ocean temperature index&lt;/a&gt; but constrained to land only. I have found some very granular LST datasets (like &lt;a href=&quot;https://neo.sci.gsfc.nasa.gov/view.php?datasetId=MOD_LSTN_CLIM_M&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;), but I don't think I've got the expertise I'd need to turn them into a yearly global timeseries (e.g. should I just take a straight mean of all the datapoints? Should I be weighing by landmass or seasonality, etc?).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my question is, does a high-level aggregated yearly mean LST dataset exist? If not, why not? And at a higher level, does my approach to investigating the Karl et al work make sense, and if so has someone who knows what they're doing already done it?&lt;/p&gt;&#xA;" OwnerUserId="8295" LastActivityDate="2017-06-05T11:53:54.933" Title="Are there datasets like the global land-ocean temperature index for land surface temperature only?" Tags="|climate|climate-change|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10523" PostTypeId="1" AcceptedAnswerId="10580" CreationDate="2017-06-04T17:28:38.910" Score="12" ViewCount="705" Body="&lt;p&gt;I was following the boarder of the US and Canada on Google Maps, because, and found these interesting circular patterns of islands near the Northwest Angle. I have heard of geologic folding but I have never heard of Swirls or Circles. What is the cause of this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5oQm8.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5oQm8.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;a href=&quot;https://www.google.com/maps/place/49%C2%B009&amp;#39;45.1%22N+94%C2%B029&amp;#39;18.1%22W/@49.1736625,-94.4245572,38537m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d49.162518!4d-94.48835&quot; rel=&quot;nofollow noreferrer&quot;&gt;Swirl of islands on Google maps&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="462" LastEditorUserId="595" LastEditDate="2017-06-30T15:33:50.287" LastActivityDate="2017-06-30T15:33:50.287" Title="What causes these circular swirls of islands?" Tags="|geomorphology|structural-geology|regional-geology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10526" PostTypeId="1" CreationDate="2017-06-05T01:18:43.057" Score="5" ViewCount="165" Body="&lt;p&gt;I was learning about the formation of Earth on &lt;a href=&quot;https://www.khanacademy.org/science/cosmology-and-astronomy/life-earth-universe/history-life-earth-tutorial/v/earth-formation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kahn Academy&lt;/a&gt; where it was mentioned that a protoplanet named Theia had a glancing impact with the earth and formed the moon. It seems like there is also newer research (&lt;a href=&quot;https://en.wikipedia.org/wiki/Theia_(planet)#cite_note-Nace2016-3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Read on Wiki&lt;/a&gt;) that suggests it was a head on collision. I'm curious if there is a current scientific consensus on this. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My understanding of this event is that a more direct hit is possible due to the identical nature of Earth and moon Oxygen isotopes. Suggesting a vigorous mixing and &lt;a href=&quot;http://science.sciencemag.org/content/351/6272/493&quot; rel=&quot;nofollow noreferrer&quot;&gt;high-angular-momentum impact.&lt;/a&gt; Meanwhile, this article suggests otherwise &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0019103503002999&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;The most favorable conditions for producing a sufficiently massive and iron-depleted protolunar disk involve collisions with an impact angle near 45 degrees and an impactor velocity at infinity &amp;lt;4 km/sec.&quot;&#xA;&lt;/a&gt; I'm assuming that if the protolunar disk was lacking iron it means the hit would not have exposed the interiors of either protoplanet in the collision and would have been more of a glancing blow. &lt;/p&gt;&#xA;" OwnerUserId="8287" LastEditorUserId="8287" LastEditDate="2017-06-07T21:52:39.630" LastActivityDate="2017-06-07T21:52:39.630" Title="Did Theia collide directly with proto-Earth?" Tags="|earth-history|planetary-science|planetary-formation|astronomy|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10528" PostTypeId="1" AcceptedAnswerId="10530" CreationDate="2017-06-05T07:58:11.913" Score="3" ViewCount="1160" Body="&lt;p&gt;Why do cities at high altitude regions, such as Lhasa, altitude 11995ft (3656 metre), have high atmospheric pressures such as 30.11inHg (101.97 kPa) in the weather report?&lt;/p&gt;&#xA;" OwnerUserId="8300" LastEditorUserId="6" LastEditDate="2017-06-06T10:43:34.120" LastActivityDate="2017-06-06T10:43:34.120" Title="Why do cities at high altitude regions have high atmospheric pressures?" Tags="|meteorology|atmosphere|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10529" PostTypeId="2" ParentId="10522" CreationDate="2017-06-05T11:53:54.933" Score="2" Body="&lt;p&gt;Yes, NASA GISS has it &lt;a href=&quot;https://data.giss.nasa.gov/gistemp/tabledata_v3/GLB.Ts.txt&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; . If you go to the &lt;a href=&quot;https://data.giss.nasa.gov/gistemp/&quot; rel=&quot;nofollow noreferrer&quot;&gt;main page&lt;/a&gt; and search for &lt;strong&gt;'Global Mean Estimates Based on Land-Surface Air Temperature Anomalies Only (Meteorological Station Data, dTs)'&lt;/strong&gt; within that page you will find the links to the above, plus northern and southern hemispheres. &lt;/p&gt;&#xA;" OwnerUserId="8217" LastActivityDate="2017-06-05T11:53:54.933" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10530" PostTypeId="2" ParentId="10528" CreationDate="2017-06-05T12:24:43.330" Score="11" Body="&lt;p&gt;The reason for this is that the reported value is the relative pressure and not the absolute pressure. If meteorological stations reported the absolute pressure, dependent on elevation, it would been really confusing. So air pressure is always adjusted to sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is also why your home barometer has to be adjusted to show the correct pressure depending on the altitude where you are.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are a link to the weather close to where I live. It is at 150 m elevation,&#xA;&lt;a href=&quot;https://www.yr.no/place/Norway/Buskerud/R%c3%b8yken/B%c3%b8dalen/hour_by_hour_detailed.html?spr=eng&quot; rel=&quot;noreferrer&quot;&gt;https://www.yr.no/place/Norway/Buskerud/R%c3%b8yken/B%c3%b8dalen/hour_by_hour_detailed.html?spr=eng&lt;/a&gt; If you seek for Drammen you will see the green line showing the same pressure but the elevation there is close to sea level 10m or so.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6258" LastEditDate="2017-06-05T17:32:43.060" LastActivityDate="2017-06-05T17:32:43.060" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10531" PostTypeId="1" AcceptedAnswerId="10534" CreationDate="2017-06-05T17:47:34.457" Score="2" ViewCount="1169" Body="&lt;p&gt;What's the difference between snow cover and fractional snow cover? Are they kind of synonyms? What would be a definition of fractional snow cover?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;thanks a lot!&lt;/p&gt;&#xA;" OwnerUserId="7256" LastActivityDate="2017-06-06T02:28:59.983" Title="What's the difference between snow cover and fractional snow cover?" Tags="|snow|reanalysis|" AnswerCount="2" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10533" PostTypeId="2" ParentId="10531" CreationDate="2017-06-06T00:14:16.077" Score="-1" Body="&lt;p&gt;I would say that snow cover is the total area of snow while fractional snow cover is the fraction of an area (e.g. a pixel in a remote sensing product) covered with snow. I suspect people get a bit sloppy and say snow cover when they mean fractional snow cover if they think it is clear what they mean from context.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-06-06T00:14:16.077" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10534" PostTypeId="2" ParentId="10531" CreationDate="2017-06-06T01:45:25.333" Score="2" Body="&lt;p&gt;Fractional Snow Cover (FSC) is a property of snow cover.  The fractional snow cover property is used in a variety of contexts, most common of which is meteorological models.  Snow cover algorithms applied to visible imagery remote sensing data are used to derive fractional snow cover for each pixel.  This information is typically re-gridded and time-averaged for use by external users.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This &lt;a href=&quot;https://www.star.nesdis.noaa.gov/goesr/product_land_snow.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;GOES site &lt;/a&gt;explains:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Most satellite-based snow cover products provide a &quot;binary&quot; map, whereby each pixel is classified as either &quot;snow&quot; or &quot;not snow&quot;. In contrast, the FSC algorithm is an optimized spectral mixture analysis that uses the broad spectrum from ABI to determine the fractional cover of snow, vegetation, and soils.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;More information about snow cover products from GOES and MODIS can be seen here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.goes-r.gov/products/baseline-snow-cover.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.goes-r.gov/products/baseline-snow-cover.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://modis.gsfc.nasa.gov/data/dataprod/mod10.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://modis.gsfc.nasa.gov/data/dataprod/mod10.php&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2017-06-06T02:28:59.983" LastActivityDate="2017-06-06T02:28:59.983" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10536" PostTypeId="1" AcceptedAnswerId="12139" CreationDate="2017-06-06T08:32:47.070" Score="6" ViewCount="108" Body="&lt;p&gt;Has anyone had a problem with significant wave height (&lt;strong&gt;swh&lt;/strong&gt;) and mean wave period (&lt;strong&gt;mwp&lt;/strong&gt;) from &lt;strong&gt;ERA-Interim&lt;/strong&gt; not matching very well with either a time series of measurements or a different model? Or does anyone know if the formulas in the model (the way they made it) have changed from one period to another? (In my case they seem to correlate better/worse at either side of 1991).&lt;/p&gt;&#xA;" OwnerUserId="8306" LastEditorUserId="2470" LastEditDate="2017-06-06T08:59:28.807" LastActivityDate="2017-08-23T18:27:27.880" Title="ERA Interim problem with Waves" Tags="|climate|oceanography|waves|reanalysis|era|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10539" PostTypeId="1" CreationDate="2017-06-06T17:05:55.873" Score="5" ViewCount="2153" Body="&lt;p&gt;There are some &lt;a href=&quot;https://www.nature.com/articles/srep19876&quot; rel=&quot;noreferrer&quot;&gt;papers&lt;/a&gt; in literature which discuss stream-aquifer interaction. They describe that the stream aquifer interaction ranges from connection to disconnection. When there is disconnection, then there is an $\textbf{inverted water table} $ below the stream and above saturated zone. I have not understood what is meant by this kind of water table?&lt;/p&gt;&#xA;" OwnerUserId="5557" LastActivityDate="2017-08-10T13:32:51.303" Title="What is meant by inverted water table?" Tags="|hydrology|groundwater|hydrogeology|water-table|unsaturated-zone|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10540" PostTypeId="2" ParentId="10539" CreationDate="2017-06-06T17:22:15.547" Score="5" Body="&lt;p&gt;An Inverted or Perched water table is a water table that is above the main or regional water table in an  unconfined aquifer.  The perched water table is generally above a layer of low permeability material such as clay.  In the image below, notice that there is an &quot;inverted&quot; water table along bottom of the perched water table.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OWE0q.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OWE0q.png&quot; alt=&quot;Perched water table.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-06-06T17:22:15.547" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10542" PostTypeId="1" CreationDate="2017-06-06T20:23:03.080" Score="1" ViewCount="147" Body="&lt;p&gt;I recently read an &lt;a href=&quot;https://weather.com/storms/tornado/news/tornado-strength-population-number-casualties&quot; rel=&quot;nofollow noreferrer&quot;&gt;article&lt;/a&gt; that said that claimed &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the stronger the tornado, the larger its area&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and generally, I think this is accepted. Why?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The vorticity equation $$\frac{D\vec{\omega}}{Dt}=\vec{\omega}\cdot\nabla\vec{u}-\vec{\omega}(\nabla\cdot\vec{u})+\frac{1}{\rho^2}\nabla\rho\times\nabla P$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;describes that convergence (decreasing area, $\nabla\cdot\vec u&amp;lt;0$) leads to increasing vorticity. Does this mean that the strongest tornadoes don't have the greatest vorticity, or am I missing something?&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-06-06T20:23:03.080" Title="Why are larger tornadoes stronger?" Tags="|tornado|mesoscale-meteorology|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10543" PostTypeId="2" ParentId="10539" CreationDate="2017-06-06T23:03:45.900" Score="1" Body="&lt;p&gt;To amplify on Gary's answer for the situation under a stream: Surface water will be connected to an unconfined groundwater aquifer if the sediments are saturated between the aquifer and the stream. If the head (the elevation of the water i.e. its pressure) is lower at the stream than the adjacent sediments, then it will be a &quot;gaining stream&quot; the water in the aquifer will flow into the stream. If the head is higher at the stream it will be a &quot;losing stream&quot; and water will flow into the aquifer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However sometimes, the water level in the aquifer drops enough that it is lower than the sediments right under the stream and the stream becomes a &quot;disconnected stream&quot;. This can occur when the sediments in the stream bed have lower permeability than the rest of the aquifer. That's a common occurrence because fine sediment transported by the stream can build up in the stream bed - called a skin effect. If a stream has intermittent flow then the stream can be disconnected when it starts to flow but the water seeping into the bed hasn't had time to fully saturate the sediments underneath.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that the gaining or losing flow can be very low. The difference in head tells you the potential flow direction but the permeability of the sediments determines how much flow you will get for a given potential. It is analogous to a battery voltage (potential) and a resistor (permeability) governing currrent (flow).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KwDpa.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KwDpa.png&quot; alt=&quot;https://www.e-education.psu.edu/earth111/node/938&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-06-06T23:03:45.900" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10544" PostTypeId="1" CreationDate="2017-06-07T00:29:14.303" Score="5" ViewCount="731" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/84vm7.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/84vm7.jpg&quot; alt=&quot;contrail1&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/rGruY.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rGruY.jpg&quot; alt=&quot;contrail2&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I observed this contrail above me today, and I noticed that the two inner contrails diverge outwards to merge with the two outer contrails. Then, as the contrails dissipate after several seconds they converge again and become closer.&lt;/p&gt;&#xA;&lt;p&gt;I doubt it's a matter of viewing perspective because I observed it when the airplane was flying both towards me and away from me.&lt;/p&gt;&#xA;&lt;p&gt;Why does that happen? My attempt to find an explanation online failed, unfortunately.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-09-10T02:32:00.353" Title="Why does this contrail diverge and then converge?" Tags="|meteorology|atmosphere|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10546" PostTypeId="1" CreationDate="2017-06-07T08:16:34.667" Score="8" ViewCount="90" Body="&lt;p&gt;Due to the attraction of our moon (and Sun) our oceans undergo an up and down movement every day. So the water rises or falls by a couple of meters. But does this type of effect also occur with our atmosphere? &lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="2470" LastEditDate="2017-06-07T08:25:18.363" LastActivityDate="2017-07-12T21:33:24.103" Title="Are there any effects on the atmosphere comparable with ebb and flood of the oceans?" Tags="|atmosphere|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10548" PostTypeId="2" ParentId="10536" CreationDate="2017-06-07T15:53:04.447" Score="1" Body="&lt;p&gt;This doesn't answer your question but I can't comment; It is worth noting that there are several changes in SST packages which drive the models. The most significant is the difference from before December 2001 and after January 2002 - it could be that there is a difference from before 1991 and after for similar reasons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It might also be worth checking if SWH or MWP are data packages used to drive the model or if they are produced at the output. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can find model formulas here: &lt;a href=&quot;https://www.ecmwf.int/sites/default/files/elibrary/2011/8174-era-interim-archive-version-20.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ecmwf.int/sites/default/files/elibrary/2011/8174-era-interim-archive-version-20.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and the reanalysis process is described here;&#xA;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/qj.828/pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://onlinelibrary.wiley.com/doi/10.1002/qj.828/pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this helps! :)&lt;/p&gt;&#xA;" OwnerUserId="6640" LastActivityDate="2017-06-07T15:53:04.447" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10549" PostTypeId="1" CreationDate="2017-06-07T17:35:17.807" Score="4" ViewCount="449" Body="&lt;p&gt;I have air temperature data from reanalysis that I want to analyze. The reanalysis data is in Kelvin, so I'm wondering why they use Kelvin. Is there any advantage or difference in analyzing temperature data as Kelvin? or is it the same as Celsius? Which one would be better if the temperature range goes from -35 to 20?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;thank you!&lt;/p&gt;&#xA;" OwnerUserId="7256" LastEditorUserId="7256" LastEditDate="2017-06-07T19:25:36.247" LastActivityDate="2017-06-07T19:25:36.247" Title="What are the advantages of analyzing temperature in Kelvin?" Tags="|temperature|data-analysis|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10550" PostTypeId="1" CreationDate="2017-06-07T18:16:15.257" Score="6" ViewCount="478" Body="&lt;p&gt;NASA publishes what it calls an &quot;estimate&quot; of the Earth's global mean surface temperature. Digging through papers I've been able to find some documentation of how these numbers are computed, but I have had a frustratingly hard time answering what seems to me a much more basic question: what is this &quot;estimate&quot; an estimate &lt;em&gt;of&lt;/em&gt;? That is, what is the abstract conceptual quantity that we'd really like to know, if we could? Without that, I don't understand how we can evaluate how well, for instance, the methods they use to blend together data sources of different resolutions and reliabilities, since the definition wouldn't have any stronger &quot;correctness&quot; criterion than just &quot;this is how we put these numbers together&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems to me that the conceptual quantity they're trying to measure is, for a given year:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Imagine gridding up the earth into equal-area grids and putting a thermometer in each one.&lt;/li&gt;&#xA;&lt;li&gt;For each thermometer, imagine taking the limit of the average reading as number of readings increases for a one-year timespan from midnight on Jan 1 to just before midnight on Dec 31 of the given year&lt;/li&gt;&#xA;&lt;li&gt;Now take the limit of the average of all those single-thermometer limits for every thermometer in your grid, as the size of the grid squares decreases.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;But this is really just a guess as to what they're after -- I have skimmed over several papers on this subject and I haven't been able to find any discussion of this at all. Is this just something basic that climate researchers know that I'm missing?&lt;/p&gt;&#xA;" OwnerUserId="8295" LastActivityDate="2017-06-07T18:16:15.257" Title="What is the &quot;global mean surface temperature change estimate&quot; an estimate of?" Tags="|climate|climate-change|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10552" PostTypeId="1" CreationDate="2017-06-08T05:04:03.667" Score="-4" ViewCount="110" Body="&lt;p&gt;In assigning serial definitions to the stratification of lunar regolith with precise ETA of first impact; what year, month, day and time did the heavy bombardment period begin?&lt;/p&gt;&#xA;" OwnerUserId="8320" LastActivityDate="2017-06-08T09:07:14.413" Title="What 'time of day' did the heavy bombardment period begin?" Tags="|moon|" AnswerCount="1" CommentCount="3" ClosedDate="2017-06-08T09:41:17.740" ContentLicense="CC BY-SA 3.0" />
  <row Id="10553" PostTypeId="1" CreationDate="2017-06-08T06:17:27.400" Score="4" ViewCount="818" Body="&lt;p&gt;Just my experience of observation: hurricanes/cyclones/typhoons in the Pacific Ocean seem to look larger than those in Atlantic Ocean (by looks I mean they occupy more grids in satellite images).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this is true and if so, what is the reason for this? Is it because the Pacific Ocean has stronger hurricanes/cyclones/typhoons?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="2470" LastEditDate="2017-06-08T09:11:45.540" LastActivityDate="2021-01-22T02:40:53.663" Title="Are hurricanes/cyclones/typhoons in the Pacific Ocean usually larger than in Atlantic Ocean?" Tags="|tropical-cyclone|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10554" PostTypeId="2" ParentId="10552" CreationDate="2017-06-08T09:07:14.413" Score="2" Body="&lt;p&gt;What makes you think the &lt;a href=&quot;http://www.abc.net.au/science/articles/2012/11/28/3642932.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;length of a day on Earth&lt;/a&gt; has been constant since the formation of the Earth?&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The length of an Earth day has been increasing slowly throughout most of the Earth's 4.5-billion-year history, says Dr Rosemary Mardling, mathematical scientist at Monash University, and it all has to do with the Moon.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&quot;The reason is that the Moon is attempting to slow down the spin of&#xA;  the Earth. The Earth was spinning very much faster when the Moon was&#xA;  formed,&quot; says Mardling.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Back when the Moon was formed the length of an Earth day was a very&#xA;  brief two to three hours, and a much closer Moon was orbiting the&#xA;  Earth every five hours.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;... the Earth slows down a little bit and the Moon moves away from the&#xA;  Earth,&quot; says Mardling.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&quot;... The spin down rate is very slow,&quot; says Mardling, &quot;It's about two&#xA;  milliseconds per century. So the Earth's day is getting longer by a&#xA;  500th of a second every century&quot;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;... Since the dinosaurs lived during the Mesozoic era, from 250&#xA;  million years ago to 65 million years ago, day length would have been&#xA;  longer than 21 hours and probably closer to 23 hours.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Given that the length of a day on Earth has never been constant throughout its history it would be totally impossible to assign a year, month day or time of day for the commencement of the heavy bombardment period or any other event in ancient geologic history.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-06-08T09:07:14.413" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10556" PostTypeId="1" AcceptedAnswerId="10560" CreationDate="2017-06-09T16:38:54.197" Score="14" ViewCount="1354" Body="&lt;p&gt;Recently I got startled by this question I asked myself and I can't seem to find any sources of answers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have hypotheses about how it could have happened:&#xA;It could have been by the fact that if you stand there you don't drift anywhere as opposed to the North Pole. Also perhaps by altitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Am I right?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What about nowadays? Do we use measurements of seismic activity to infer the shape of Antarctica? Are there other methods?&lt;/p&gt;&#xA;" OwnerUserId="8327" LastEditorUserId="2470" LastEditDate="2021-07-06T07:06:46.530" LastActivityDate="2021-07-06T07:06:46.530" Title="How and when people first realized that Antarctica is a continent?" Tags="|antarctica|continent|history|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10557" PostTypeId="2" ParentId="10556" CreationDate="2017-06-09T17:46:55.903" Score="8" Body="&lt;p&gt;Probably the first recorded observation (and certainly one of the first) of the Antarctic mainland was of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Trinity_Peninsula&quot; rel=&quot;noreferrer&quot;&gt;Trinity Peninsula&lt;/a&gt;, part of the Antarctic Peninsula, by Edward Bransfield in 1820. Even from a distance, it's obvious that it's solid land.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tGBv1.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tGBv1.jpg&quot; alt=&quot;Trinity Peninsula&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;Picture source: &lt;a href=&quot;http://www.swisseduc.ch/glaciers/antarctic/geology/6_plate_margin_activity/index-en.html?id=1&quot; rel=&quot;noreferrer&quot;&gt;swisseduc.ch&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It could have been by the fact that if you stand there you don't drift anywhere as opposed to the North Pole.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;While the Antarctic ice sheets are far more stable than the north polar sea ice, they do actually move: at the South Pole, the motion is only about &lt;a href=&quot;https://www.ngs.noaa.gov/GRD/GPS/Projects/SOUTH_POLE/south_pole.html&quot; rel=&quot;noreferrer&quot;&gt;10 metres per year&lt;/a&gt;, but coastal glaciers can &lt;a href=&quot;https://earthobservatory.nasa.gov/IOTD/view.php?id=7544&quot; rel=&quot;noreferrer&quot;&gt;move much faster&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2017-06-09T17:54:58.017" LastActivityDate="2017-06-09T17:54:58.017" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10560" PostTypeId="2" ParentId="10556" CreationDate="2017-06-10T15:04:18.397" Score="16" Body="&lt;p&gt;The idea of a southern continent is older than the actual discovery of the Antarctica. There was an expectation of the possible existence of a &lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Terra_Australis&quot; rel=&quot;noreferrer&quot;&gt;Terra Australis&lt;/a&gt;&lt;/em&gt; balance the global landmasses and the theory went far back. However, those models were not based on true evidence but rather aesthetic arguments that later just happened to come true. In contradiction, landmasses were also expected to surround the North Pole in the Arctic, and that turned out to be wrong. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/uucWk.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uucWk.jpg&quot; alt=&quot;https://en.wikipedia.org/wiki/North_Pole#/media/File:Mercator_north_pole_1595.jpg&quot;&gt;&lt;/a&gt;&#xA;&lt;em&gt;Mercator (1595) map of the North Pole and surrounding continent. Some practical canals are suggested to facilitate the short cut from Atlantic to Pacific&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There have never been any human population on Antarctica prior to western explorers but &lt;a href=&quot;https://en.wikipedia.org/wiki/Ui-te-Rangiora&quot; rel=&quot;noreferrer&quot;&gt;Maori navigators&lt;/a&gt;, had experienced the cold waters for centuries. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the 18th century, famous explorers as James Cook and &lt;a href=&quot;https://en.wikipedia.org/wiki/Vostok_(sloop-of-war)&quot; rel=&quot;noreferrer&quot;&gt;Bellingshausen&lt;/a&gt; came close and made sightings that pushed the limits of whaling and hunting, but there was little interest or possibility to actually land and map the area. &lt;a href=&quot;http://4.bp.blogspot.com/-Up7Gvb5eyM4/VgNNSSIREfI/AAAAAAAAFCg/IDdNTl2EKdo/s1600/antarctica%2B-%2Bjames%2Bcook%2Bdidn%2527t%2Bknow%2Bwhere%2Bhe%2Bwas%2Bgoing.jpg&quot; rel=&quot;noreferrer&quot;&gt;Cook's circumnavigation&lt;/a&gt; rather limited the expected extent of a much larger Terra Australis. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Landings and activities were focused on the sub-antarctic islands and to a minor extent, the peninsula. There was little reason for anyone to cross the dangerous &lt;a href=&quot;https://en.wikipedia.org/wiki/Roaring_Forties&quot; rel=&quot;noreferrer&quot;&gt;roaring fourties&lt;/a&gt;, furious fifties and screaming sixties to get to icy waters with little prospect of economic profit or even survival. Stories about early explorers have been questioned and &lt;a href=&quot;https://en.wikipedia.org/wiki/Piri_Reis_map#The_Antarctic_coast&quot; rel=&quot;noreferrer&quot;&gt;proved wrong&lt;/a&gt; multiple times. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/C4lYt.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/C4lYt.jpg&quot; alt=&quot;https://en.wikipedia.org/wiki/History_of_Antarctica#/media/File:Geography_world_map.jpeg&quot;&gt;&lt;/a&gt;&#xA;&lt;em&gt;Map from 1770 before the continent was descovered&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first concepts of an Antarctic continent based on actual sights probably originate from The United States Exploring Expedition (1839-42). &lt;a href=&quot;https://en.wikipedia.org/wiki/Charles_Wilkes#The_South_Seas_expedition&quot; rel=&quot;noreferrer&quot;&gt;Wilkes&lt;/a&gt; described the findings as a &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;vast Antarctic continent [protected by] an impenetrable barrier of&#xA;  ice&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It's not easy to access the coast and the landing opportunities are few, especially in East Antarctica. USEE's findings have been questioned later and there seems to have been little substance in the claims. The sighted coast might as well have been just clouds. &lt;a href=&quot;https://en.wikipedia.org/wiki/James_Clark_Ross&quot; rel=&quot;noreferrer&quot;&gt;Ross&lt;/a&gt; even accused him for cartographical deceit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even as exploration continued and increased from the 1890s, the nature of the continent continued to puzzle explorers and adventurers. There was e.g. no consensus whether East and West Antarctica belonged to the same continent or if an icy sea, similar to the Arctic, separated the isolated visited outcrops. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZGO52.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZGO52.jpg&quot; alt=&quot;Taylor1917&quot;&gt;&lt;/a&gt;&#xA;&lt;em&gt;Taylor (1914) &lt;a href=&quot;http://www.jstor.org/stable/1778593_&quot; rel=&quot;noreferrer&quot;&gt;http://www.jstor.org/stable/1778593&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Griffith Taylor, Geologist to Captain Scott's expedition writes in his very entertaining report from 1914:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Undoubtedly one of the most fascinating geographical problems, if&#xA;  not the most attractive now that both poles are discovered, is to determine if there are one or two continents at the South Pole.&#xA;  At an animated discussion in the hut, I pointed out that the South Georgia loop carried the &quot;Pacific&quot; type of coast into West Antarctica, whereas Victoria Land (and apparently Prince Leopold Land) belong to that type characterized by block faults and known as the Atlantic type.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Even as the geologists of the time had a developed vocabulary for rock types and correlations, they still couldn't be sure that Antarctica was indeed one continent or two. As a side note, it should be mentioned that they are indeed right in the doubts. Today we know that East and West Antarctica have very different history and properties. See e.g. &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S1342937X10001759&quot; rel=&quot;noreferrer&quot;&gt;Boger (2011)&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZbBtG.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZbBtG.jpg&quot; alt=&quot;Private photo.&quot;&gt;&lt;/a&gt;&#xA;&lt;em&gt;Large areas of Antarctica is ice-free, eg. this valley in Vestfold Hills, East Antarctica. The area was first explored in the mid to late 1900's but sightings of outcrop would assure explorers that they actually saw the continent they were expecting and not floating ice.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geologists could also early correlate the rare findings from Antarctica with surrounding continents and started to reconstruct the Gondwana assembly, a work that is still ongoing and due to the lack of outcrops in Antarctica is to a large extent based on geophysical data. Still, geologists and geophysicists are looking for similarities in Africa, India and Australia to understand the nature of the Antarctic geology under the ice cover. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With aviation, it was finally possible to map the hinterland of the continent, and great discoveries were made as late as 1946–47 during &lt;a href=&quot;https://en.wikipedia.org/wiki/Operation_Highjump&quot; rel=&quot;noreferrer&quot;&gt;Operation Highjump&lt;/a&gt; and during the Soviet's expeditions in the 50's. &#xA; (Don't miss this short footage of the discovery of Bunger Hills: &#xA;&lt;a href=&quot;https://www.youtube.com/watch?v=cGtvXOvqYZg&quot; rel=&quot;noreferrer&quot;&gt;Youtube&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as I know, it was not until the International Geophysical Year (&lt;a href=&quot;https://en.wikipedia.org/wiki/International_Geophysical_Year&quot; rel=&quot;noreferrer&quot;&gt;IPY&lt;/a&gt;) 1957-58 an international effort deploy scientists and collect data firmly defined the physical shape of the continent, that we are still refining today. &lt;a href=&quot;http://www.scar.org/&quot; rel=&quot;noreferrer&quot;&gt;International collaboration&lt;/a&gt; appears to be the key to successful research in Antarctica. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seismic data is indeed very important to understand the Antarctic lithosphere, but the resolution is low due to the low seismicity and especially the limited number of deployed seismometers. This is, however, improving during recent years and a number of new studies are using seismic tomography and receiver functions to measure the continental shape of Antarctica. See e.g. &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2014JB011332/abstract;jsessionid=125A70E837738869BB3371BDF9D42380.f02t02&quot; rel=&quot;noreferrer&quot;&gt;An et al (2015a)&lt;/a&gt; and &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2015JB011917/abstract&quot; rel=&quot;noreferrer&quot;&gt;An et al (2015b)&lt;/a&gt;. Seismic data is also used to understand the ice sheets and to derive the heat flux that causes basal melting. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also very important is satellite potential field data. Gravity data e.g. &lt;a href=&quot;http://www.esa.int/Our_Activities/Observing_the_Earth/GOCE&quot; rel=&quot;noreferrer&quot;&gt;GOCE&lt;/a&gt; from ESA is and important constraints, but the resolution is low. &#xA;Magnetic data especially from airplanes but also satellites as the flight lines are still sparse is used to map and understand geological terranes covered by ice. The &lt;a href=&quot;http://www.antarctica.gov.au/living-and-working/stations/casey/this-week-at-casey/2017/this-week-at-casey-17-february-2017/farewell-from-the-201617-icecap-crew&quot; rel=&quot;noreferrer&quot;&gt;ICECAP&lt;/a&gt; project is collecting high-resolution data from flights to improve our understanding of the ice sheets, glaciers and also the bedrock under. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good start to look for data and information about the physical nature of Antarctica is to download the datasets in the &lt;a href=&quot;http://quantarctica.npolar.no/&quot; rel=&quot;noreferrer&quot;&gt;Quantarctica&lt;/a&gt; package. It includes gravity and magnetic data (that should be updated soon). The bedrock elevation data can show you that actually large parts of the Antarctic continent are submerged under sea level due to the weight of the ice sheets, subglacial erosion and lack of major endogenic processes that can cause rapid uplifts. For a geologist, it's however not the elevation that the chemical composition and thickness of the crust that define it as one continuous continent. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LAS6H.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LAS6H.jpg&quot; alt=&quot;Privat photo. From helicopter over West Ice Shelf, East Antarctica&quot;&gt;&lt;/a&gt;&#xA;&lt;em&gt;Rather inaccessible.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Finally, it's worth notice that the Internet is flooded by ridiculous conspiration theories about the lack of information about Antarctica. Whiles being entertaining to watch (with a couple of beers or so), there is not any truth in them, but the phenomina gives in insight in how myths and lies are created and blooming on the internet and how important it is to stay critical about unreliable sources. The reality is that Antarctica is very difficult and expensive to access and, thankfully, its sensitive nature is well protected by &lt;a href=&quot;http://www.ats.aq/e/ats.htm&quot; rel=&quot;noreferrer&quot;&gt;international agreements&lt;/a&gt;.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-06-11T01:58:03.100" LastActivityDate="2017-06-11T01:58:03.100" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10561" PostTypeId="1" CreationDate="2017-06-12T07:00:40.833" Score="5" ViewCount="84" Body="&lt;p&gt;I would like to know what the equivalent of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Courant%E2%80%93Friedrichs%E2%80%93Lewy_condition&quot; rel=&quot;nofollow noreferrer&quot;&gt;CFL criterion&lt;/a&gt; is for atmospheric models based of spectral grids. In other words, how do you find the necessary horizontal resolution in meters for spectral grids?&lt;/p&gt;&#xA;" OwnerUserId="8337" LastEditorUserId="6298" LastEditDate="2017-06-12T07:53:09.850" LastActivityDate="2017-06-12T07:53:09.850" Title="What is the equivalent of CFL criterion when using spectral models?" Tags="|numerical-modelling|grid-spacing|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10564" PostTypeId="1" AcceptedAnswerId="10566" CreationDate="2017-06-12T12:35:11.273" Score="2" ViewCount="892" Body="&lt;p&gt;I live in New Jersey.  Now that summer is coming on us, temperatures and outdoor relative humidity are both increasing.  I've noticed the few years that I've lived here that there seems to be a rough correlation with a day's high temperature and the relative humidity.  I've always found this odd, since for a fixed amount of moisture in the air, relative humidity will go down with increasing air temperature.  However, the hottest days (as the thermometer reads, not just as I feel) also seem to have the highest relative humidity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I lived in Hong Kong for two years and the same thing seemed to happen there.  The hottest days also had the highest humidity (and were usually accompanied with the formation of a typhoon).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What makes relative humidity go up with hotter days?&lt;/p&gt;&#xA;" OwnerUserId="8339" LastActivityDate="2017-12-02T21:29:58.400" Title="Why does relative humidity seem to correlate with high temperature (at least where I live)?" Tags="|meteorology|temperature|humidity|" AnswerCount="5" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10565" PostTypeId="2" ParentId="10564" CreationDate="2017-06-12T13:53:47.273" Score="0" Body="&lt;p&gt;I have two ideas, you may need to test them out. They may not be mutually exclusive.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The hottest days are clear days, and relative humidity peaks at night/dawn.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Relative humidity can approximately measure the ratio of condensation to evaporation. Therefore, during the day (especially clear days, where you will get the warmest days), water is evaporated off the ground, leading to higher mixing ratios of water vapor. When night occurs, the rate of condensation increases, and the rate of evaporation decreases, leading to high values of RH. In some instances, this may lead to fog.&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;The Gulf of Mexico is both a source of moisture and a source of maritime tropical air.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Many times, the hottest days occur due to clear skies. Clear skies, generally are associated with areas of high pressure. High pressure areas have a clockwise circulation in the Northern Hemisphere, which brings both warm air and moisture from the Gulf of Mexico.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-06-12T13:53:47.273" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10566" PostTypeId="2" ParentId="10564" CreationDate="2017-06-12T13:53:57.187" Score="4" Body="&lt;p&gt;In coastal New Jersey, relative humidity is maximal in the early fall when the ocean temperature is warmest, and minimal in early spring when the ocean is coldest.  However, the monthly variation is rather small:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Atlantic City, New Jersey:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;70 January&lt;br&gt;&#xA;69 February&lt;br&gt;&#xA;67 March&lt;br&gt;&#xA;66 April&lt;br&gt;&#xA;71 May&lt;br&gt;&#xA;73 June&lt;br&gt;&#xA;74 July&lt;br&gt;&#xA;76 August&lt;br&gt;&#xA;76 September&lt;br&gt;&#xA;75 October&lt;br&gt;&#xA;73 November&lt;br&gt;&#xA;71 December&lt;br&gt;&#xA;72 Annual &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Newark, New Jersey  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;65 January&lt;br&gt;&#xA;63 February&lt;br&gt;&#xA;60 March&lt;br&gt;&#xA;58 April&lt;br&gt;&#xA;62 May&lt;br&gt;&#xA;63 June&lt;br&gt;&#xA;63 July&lt;br&gt;&#xA;66 August&lt;br&gt;&#xA;68 September&lt;br&gt;&#xA;66 October&lt;br&gt;&#xA;67 November&lt;br&gt;&#xA;67 December&lt;br&gt;&#xA;64 Annual &lt;/p&gt;&#xA;&#xA;&lt;p&gt;source: &lt;a href=&quot;https://www.currentresults.com/Weather/New-Jersey/humidity-by-month.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.currentresults.com/Weather/New-Jersey/humidity-by-month.php&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="248" LastActivityDate="2017-06-12T13:53:57.187" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10568" PostTypeId="2" ParentId="9341" CreationDate="2017-06-12T15:15:40.167" Score="2" Body="&lt;p&gt;&lt;a href=&quot;http://wdc.kugi.kyoto-u.ac.jp/dstdir/dst2/onDstindex.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Disturbance storm time index&lt;/a&gt; is a measure of the weakened horizontal component of Earth magnetic field during great magnetic disturbances. The depression is often flanked by peaks, that initiates and ends the storm. &lt;a href=&quot;https://en.wikipedia.org/wiki/Disturbance_storm_time_index&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dst&lt;/a&gt; is published by &lt;a href=&quot;http://wdc.kugi.kyoto-u.ac.jp/dstdir/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kyoto University&lt;/a&gt; and more information about the methods and references are available on the web page. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Dst index represents the axially symmetric disturbance magnetic field at the dipole equator on the Earth's surface. Major disturbances in Dst are negative, namely decreases in the geomagnetic field. These field decreases are produced mainly by the equatorial current system in the magnetosphere, usually referred to as the ring current. The neutral sheet current flowing across the magnetospheric tail makes a small contribution to the field decreases near the Earth. Positive variations in Dst are mostly caused by the compression of the magnetosphere from solar wind pressure increases. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Sugiura and Kamei, IAGA Bulletin No 40 (1991)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Measures are presented as the deviation from the average magnetic field strength, measured in the SI unit &lt;a href=&quot;https://en.wikipedia.org/wiki/Tesla_(unit)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tesla $T$&lt;/a&gt; at time $t$. In this context, the magnetic field is very weak, so the nano prefix $n$ is usually used. Magnetic field strength can be derived from weight (in $kg$), electric charge (in Coulomb $C$) and time in second ($s$) as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$T =\frac{kg}{C \times s}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;if you integrate with time (in seconds, $s$) you'll get for each unit: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$T \times s =\frac{kg}{C}$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The relation of electric charge and weight is used as a measure of &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiation_exposure&quot; rel=&quot;nofollow noreferrer&quot;&gt;Radiation exposure&lt;/a&gt;, often given in &lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Roentgen_(unit)&quot; rel=&quot;nofollow noreferrer&quot;&gt;röntgen&lt;/a&gt;&lt;/em&gt; ($R$) and related as:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$1 \frac{C}{kg} = 3876 R$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Technically, your integral will, therefore, be a measure of increased radiation exposure, &lt;a href=&quot;https://en.wikipedia.org/wiki/Kerma_(physics)&quot; rel=&quot;nofollow noreferrer&quot;&gt;kinetic energy released per unit mass&lt;/a&gt;, for the time you integrate over. You could convert it to röntgen ($2.58×10^{−4} C/kg = R$) but note that the calculated product describes the deviation, not the absolute ionization.&lt;/p&gt;&#xA;" OwnerUserId="2536" LastActivityDate="2017-06-12T15:15:40.167" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10569" PostTypeId="2" ParentId="10546" CreationDate="2017-06-12T17:44:12.267" Score="-1" Body="&lt;p&gt;The moon has the same effect on every part of our lovely(I think). The effect is much more clear to see on the ocean because water is less subtle than air-we see the water and see right through the air. The moon also has the same effect on the land and we don't even notice. &lt;/p&gt;&#xA;" OwnerUserId="8340" LastActivityDate="2017-06-12T17:44:12.267" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10570" PostTypeId="2" ParentId="7873" CreationDate="2017-06-12T23:07:06.287" Score="2" Body="&lt;p&gt;My suggestion would be to use shade cloth. You can get it in different densities and different colours. I know this is not the same as clouds, but get her to think about what the differences are and how that might affect the results. If I were a judge I would be very impressed to see a section like that on the poster.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-06-12T23:07:06.287" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10571" PostTypeId="2" ParentId="10564" CreationDate="2017-06-12T23:29:43.023" Score="0" Body="&lt;p&gt;Water from open water bodies will evaporate more rapidly at warmer temperatures but, more importantly, transpiration of moisture by vegetation increases unless the temperatures get so high and the plants get water stressed that they shut down the stomata in their leaves to slow the transpiration. So you basically have green vegetation pumping water into the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The relationship between temperature and transpiration is not linear and depends on the available water. In dry climates the evapotranspiration (evaporation + transpiration) is water limited. The evapotranspiration approaches a maximum value called the potential evapotranspiration if there is enough water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even though it takes more water to reach a given relative humidity in warm air, there is enough water available to increase the water vapour in the air and  relative humidity. You have probably noticed nights where it cools down and the air becomes saturated forming mist.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-06-12T23:29:43.023" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10572" PostTypeId="1" CreationDate="2017-06-13T04:09:06.357" Score="5" ViewCount="492" Body="&lt;p&gt;I have cation and anion water chemistry data for some samples and I intend(ed) to generate &lt;a href=&quot;https://en.wikipedia.org/wiki/Piper_diagram&quot; rel=&quot;nofollow noreferrer&quot;&gt;piper diagrams&lt;/a&gt; for the same.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, data for some parameters was not obtained during the determinations of the abovementioned and the software I am using won't generate a piper diagram without data for some parameters like sulfate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any way to generate the diagram without some data?&lt;/p&gt;&#xA;" OwnerUserId="5273" LastEditorUserId="2536" LastEditDate="2017-06-13T13:28:53.497" LastActivityDate="2017-06-13T13:28:53.497" Title="Is there a software or means that can generate piper diagrams without some data?" Tags="|water|software|visualization|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10573" PostTypeId="2" ParentId="7825" CreationDate="2017-06-13T09:32:07.960" Score="0" Body="&lt;p&gt;In order to convert an area to a mass of soil you need the &lt;strong&gt;depth&lt;/strong&gt; and &lt;strong&gt;bulk density&lt;/strong&gt; of the section of the soil profile you are interested in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The term &quot;furrow-slice&quot; is a bit archaic, but common in agriculture, and refers to some area sliced to plow-depth (approx 15 cm). For example, if someone said they applied 50 kg-P/ha, they meant 50 kg-P per ha furrow slice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;A common short-cut:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$1\text{ ha furrow slice}\approx2.2\times10^6$ kg, or $1\text{ acre furrow slice}\approx2\times10^6 \text{ lbs}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From there its just unit conversion, something similar to the follow should suffice:&#xA;$$&#xA;\frac{50\text{ kg-N}}{2.2\times10^6\text{ kg-soil}}=\frac{\text{X g-N}}{20\text{ g-soil}}\longrightarrow \frac{\text{X g-N}}{\text{%N of fertilizer}}\longrightarrow\text{X g-fertilizer}&#xA;$$&lt;/p&gt;&#xA;" OwnerUserId="8343" LastActivityDate="2017-06-13T09:32:07.960" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10575" PostTypeId="1" AcceptedAnswerId="10578" CreationDate="2017-06-13T11:44:55.257" Score="5" ViewCount="753" Body="&lt;p&gt;I came across this question in my book, it says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The fertility of the soil increases when there is a lot of ....... in it.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The choices to fill the space were:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Nitrogen - nodular bacteria - fungi&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I would exclude fungi as in my course I don't have anything says that fungi affect the fertility of the soil. Both nitrogen and nodular bacteria are good choices and I am confused between them. Nitrogen is an important nutrient, nodular bacteria are the nitrogent-fixing bacteria, so both are important to the firtility of the soil, but I chose nitrogen, as I thought it is more correct, but I found that the answer was &quot;nodular bacteria&quot; so why is this? Is there anything I don't understand?&lt;/p&gt;&#xA;" OwnerUserId="6908" LastEditorUserId="2470" LastEditDate="2017-06-13T14:09:11.173" LastActivityDate="2019-08-25T12:53:40.350" Title="The fertility of the soil" Tags="|homework|soil|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10576" PostTypeId="1" CreationDate="2017-06-13T12:32:42.353" Score="1" ViewCount="96" Body="&lt;p&gt;It has been noticed in the field multiple times that the field produced GOR is well below the Solution GOR (obtained from PVT properties).&#xA;Based on Industry observed production data globally, I would like to know the possible reasons from both reservoir and production engineering perspectives that can lead to such discrepancies .&#xA;Further, please indicate any specific algorithms/concepts which can help mitigate the effect of the above mentioned discrepancy in the allocation of the monthly gas production volumes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can you to please take some time from your busy schedule and provide the answer to the question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks in Advance!&lt;/p&gt;&#xA;" OwnerUserId="8338" LastActivityDate="2017-06-13T12:32:42.353" Title="Possible reasons for field GOR being below Solution GOR(Rs)" Tags="|petroleum|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10577" PostTypeId="2" ParentId="10575" CreationDate="2017-06-13T13:59:51.420" Score="5" Body="&lt;h3&gt;What does 'nitrogen' mean?&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Nitrogen might mean gaseous $N_2$. It might also mean compounds, which contain nitrogen, such as nitrate, ammonia and ammonium.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;$N_2$&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;$N_2$ cannot be metabolized by most plants because it is to inert. You need bacteria or plants (e.g. Legume family plants) to perform nitrogen fixation. During this processes the $N_2$ is converted into bio-available compounds such as ammonia. If these plants/bacteria are not present, the $N_2$ is useless and does not increase the fertility.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Nitrate and Ammonium/Ammonium&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Ammonium and nitrate can directly be 'used' by plants and soil bacteria. Therefore, if we provide these compounds, we increase the fertility.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Summary&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Generally, 'nitrogen' does not increase the fertility of soils but depends on how it is bound - elemental or in a bio-available form. Therefore, 'nitrogen' does not necessarily increase the fertility. In contrast, nitrogen fixing bacteria do increase the fertility of the soil (also long as $N_2$ concentrations in the atmosphere are as high as present).&lt;/p&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2017-06-13T13:59:51.420" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10578" PostTypeId="2" ParentId="10575" CreationDate="2017-06-13T14:07:48.017" Score="8" Body="&lt;p&gt;From this paper from 1958 (page 2), &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... &lt;strong&gt;gaseous nitrogen&lt;/strong&gt; of the atmosphere represents a vast store of potential&#xA;  fertility. It &lt;strong&gt;is not directly available to plants&lt;/strong&gt;. Nitrogen-fixing bacteria, how-&#xA;  ever, absorb this gas from the soil solution and convert it to cell protein.&#xA;  When the cells die, other microbes attack the protein and convert the nitro-&#xA;  genous constituents to ammonium, which then becomes an available nutrient.&#xA;  Similarly, microbial action on plant and animal residues releases the many&#xA;  combined nutrients from their unavailable forms.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;From this, one of the criteria for soil to be fertile is the availability of nitrogen to be available to plants in a readily usable form. In a two stage process, one group of microbes (bacteria) fixes the nitrogen by converting into a protein, within their cells. When this group of microbes die, another group of microbes uses these proteins to produce ammonia, which is a nutrient that plants can use. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, as &lt;a href=&quot;http://www.astrobio.net/also-in-news/bacteria-needed-to-make-fertile-soil/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article states&lt;/a&gt;, dead bacteria are critical to soil fertility, because nearly 40 percent of a the biomass of bacteria are converted to organic soil components.&#xA;strong text&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Nitrogen_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Nitrogen Cycle&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1mVrZ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1mVrZ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="-1" LastEditDate="2017-10-01T01:04:11.620" LastActivityDate="2017-10-01T01:04:11.620" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10580" PostTypeId="2" ParentId="10523" CreationDate="2017-06-13T20:02:02.560" Score="7" Body="&lt;p&gt;Near the Lake of the Woods, the island swirl or vortex is due to structures in bedrock beneath the lake.  The rocks in this area are old and have been folded by tectonic action. The area has either been folded into a dome or a basin, exposing different layers of bedrock. Glacial activity afterwards has 'flattened'the area, and differential erosion within the folded area formed valleys that flooded where the rock eroded faster. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.mhs.mb.ca/docs/transactions/1/lakeofthewoods.shtml&quot; rel=&quot;noreferrer&quot;&gt;Geologic history of The Lake of the Woods.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-06-13T20:02:02.560" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10581" PostTypeId="1" AcceptedAnswerId="10659" CreationDate="2017-06-13T20:27:24.443" Score="2" ViewCount="504" Body="&lt;p&gt;I've been working with GFS data in Python using pygrib, and have been able to download and process data stored in .grb and .grib2 file formats from the NCEP archive ftp site. When I switch over to try to open grib files from the real time analysis, however, I'm not able to. I've tried downloading manually and changing the ending of the file to .grib2 and .grb, but neither has worked. Here's the ftp site that I'm trying to access for reference: &lt;a href=&quot;http://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/gfs.2017061300/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/gfs.2017061300/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8348" LastActivityDate="2019-04-01T17:46:02.797" Title="Not able to open .f000 file formats in pygrib" Tags="|ncep|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10583" PostTypeId="1" AcceptedAnswerId="10584" CreationDate="2017-06-13T21:22:28.397" Score="2" ViewCount="4605" Body="&lt;p&gt;Why should this figure represent a thrust fault?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/y6ELG.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/y6ELG.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I know this might be a stupid question, but I really want to understand. Since thrust faults are reverse faults why in the figure above if we turned the photo 90 degrees clockwise like this&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0rxQW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0rxQW.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;we don't get the same shape as this&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xyGmH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xyGmH.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I think that in faults in general the fault plane is inclined to the horizontal, and the hanging wall is the mass of rocks above the fault plane, i.e., the side at which the angle between the fault plane and the horizontal is larger, and the foot wall is the mass of rocks below the fault plane, i.e., the side at which the angle between the fault plane and the horizontal is smaller.&#xA;In the second figure, we have a hanging wall on the left side and we have a foot wall on the right side, and it seems that the hanging wall is moving down relative to the foot wall, and that's what happens in normal faults not reverse ones, right? So why we consider the thrust fault in figure one as a reverse fault?&lt;/p&gt;&#xA;" OwnerUserId="6908" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-06-13T22:03:00.577" Title="Why should this be a thrust fault?" Tags="|structural-geology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10584" PostTypeId="2" ParentId="10583" CreationDate="2017-06-13T22:03:00.577" Score="5" Body="&lt;p&gt;First don't rotate the whole thing, you are just confusing yourself by rotating the bedding plane. You can't rotate the bedding planes and expect faults to match up like that. Your eye is treating the bedding plane as horizontal which makes it a completely different from of fault.&lt;/p&gt;&#xA;&lt;p&gt;A thrust fault is just a reverse fault with a shallow fault angle.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/yarhU.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yarhU.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Pay attention to how the bedding planes move relative to each other notice how they begin to double up in both forms of reverse fault, while in a normal fault sections begin to disappear in the middle, being lost from hypothetical drill core entirely. In the reverse faults if you drilled down through the blocks there are areas where you would drill through the dark central bed twice while in the normal there are places where you would never hit it at all.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-06-13T22:03:00.577" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10586" PostTypeId="2" ParentId="10564" CreationDate="2017-06-14T02:54:28.013" Score="0" Body="&lt;p&gt;[I've decided to severely abuse the wiki feature by posting what I've found so far and hoping that someone else, possibly me, will do more and more work on this problem until it asymptotically approaches completion without ever quite reaching it; as with any wiki answer, please feel free to mercilessly edit and re-arrange what I've written -- for my first attempt, I am writing mostly in chronological order]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I've done so far:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Found the nearest reliable weather station to Lawrenceville, NJ using programs I've already written (&lt;a href=&quot;https://github.com/barrycarter/bcapps/blob/master/WEATHER/bc-weather-text.pl&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://github.com/barrycarter/bcapps/blob/master/WEATHER/bc-weather-text.pl&lt;/a&gt; does part of the work; &lt;a href=&quot;http://lawrenceville.nj.weather.94y.info/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://lawrenceville.nj.weather.94y.info/&lt;/a&gt; is one place to find the results). This turns out to be &quot;TRENTON MERCER COUNTY AIRPORT , NJ, United States (KTTN)&quot;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Because I want to use isd-lite data (&lt;a href=&quot;https://www1.ncdc.noaa.gov/pub/data/noaa/isd-lite/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www1.ncdc.noaa.gov/pub/data/noaa/isd-lite/&lt;/a&gt;), I need to find the numerical code for KTTN, I can't just use the four letter identifier.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;To do this, I use the master identifier database, my personal copy is at &lt;a href=&quot;https://github.com/barrycarter/bcapps/blob/master/WEATHER/master-location-identifier-database-20130801.csv&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://github.com/barrycarter/bcapps/blob/master/WEATHER/master-location-identifier-database-20130801.csv&lt;/a&gt; -- the entry for KTTN reads:&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;USA,US,United States,NJ,Mercer County,Trenton|Altura,Mercer County Airport,,USa KTTN,KTTN,TTN,,14792,TTN,m,KTTN,A,ICA12 ICA10 ICA09,TTN,A,FAA13 FAA12 FAA11 FAA10,,,,724095,,14792,,,40.27669111,-74.81346833,N,FAA13 FAA12 FAA11 FAA10,64.6,A,FAA13 FAA12 FAA11 FAA10,59,,,America/New_York,US-08628,,,,,ADJ/20120717,40,-74&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The two key numbers here are &quot;724095&quot; and &quot;14792&quot;. If I look in &lt;a href=&quot;https://www1.ncdc.noaa.gov/pub/data/noaa/isd-lite/1999/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www1.ncdc.noaa.gov/pub/data/noaa/isd-lite/1999/&lt;/a&gt; for example, the data I seek will be in the &quot;724095-14792-1999.gz&quot; file.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Curation: This station has data from 1973-2015 (2016 data exists, but I'm using my personal collection, which doesn't have it), but some of the data is missing entirely (no line of data for a given hour) and some of the data has a missing temperature or dewpoint. I exclude these lines.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;This data includes the temperature and dewpoint, but not the relative humidity. To compute the relative humidity, I used the formula from &lt;a href=&quot;http://icoads.noaa.gov/software/other/profs_short&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://icoads.noaa.gov/software/other/profs_short&lt;/a&gt; (which is based on the Clausius-Clapeyron equation).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;I then rounded the temperature to the nearest degree Celsius and plotted the average humidity for each rounded temperature:&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WJagl.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WJagl.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This &quot;trilinear&quot; function fits the data fairly well:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$-0.0135991 \left| x-21 \right|-0.00131261 \left| x-1 \right|-0.0075821&#xA; x+0.899765$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kEsWG.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kEsWG.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I still need to look at standard deviation for each point and do many other things, continuing work at &lt;a href=&quot;https://github.com/barrycarter/bcapps/blob/master/STACK/bc-nj-temp-hum.m&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://github.com/barrycarter/bcapps/blob/master/STACK/bc-nj-temp-hum.m&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user967" LastActivityDate="2017-06-14T02:54:28.013" CommentCount="0" CommunityOwnedDate="2017-06-14T02:54:28.013" ContentLicense="CC BY-SA 3.0" />
  <row Id="10587" PostTypeId="2" ParentId="10347" CreationDate="2017-06-14T04:38:19.003" Score="1" Body="&lt;p&gt;You are correct. Isotropy means that the property at some specified point (X,Y,Z) is the same, whether the measurement is made along any direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the property varies depending on which direction you make the measurement in, then that property is said to be &quot;anisotropic&quot;. For example, the permeability of a material (i.e. its ability to conduct fluids) may be anisotropic if fluid can move preferentially in one direction and it would be difficult for it to move in a different direction (like the tubes below). This means, the permeability of this material at a given point (X,Y,Z) depends on which direction you make the measurement, i.e. high permeability parallel to the tubes, low permeability otherwise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QZJ4I.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QZJ4I.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Transverse isotropy (also called hexagonal symmetry) is a special kind of anisotropy in which there exists a special &quot;axis of symmetry&quot; such that the property you are measuring appears to be the same as you make measurements perpendicular to this axis. Basically, rotating around this axis of symmetry, the property looks pretty much the same, i.e. it is isotropic in this transverse direction. However, once you go off axis, then the measured property will change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DWNbb.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DWNbb.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In geology (especially in sedimentary geology), transverse isotropy is usually a good approximation to many phenomena (elasticity, permeability, heat conductivity, etc.) due to the fact rocks are deposited mostly horizontally. This means that things will look very similar laterally (in both N-S and E-W directions) but very different vertically.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/G4BVh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G4BVh.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, transverse isotropy is just an approximation to the much more complex nature of real rocks. If you were to add multiple sets of fractures to a rock on top of its layered nature, you will need to use a &quot;less symmetric&quot; model to describe it: orthorhombic, monoclinic, or triclinic. But for most practical purposes, transverse isotropy does a pretty good job.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this helps!&lt;/p&gt;&#xA;" OwnerUserId="4636" LastActivityDate="2017-06-14T04:38:19.003" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10588" PostTypeId="1" AcceptedAnswerId="10605" CreationDate="2017-06-14T08:49:02.983" Score="10" ViewCount="3656" Body="&lt;p&gt;Frontal zones (e. g. a warm or a cold front) are connected to low-pressure systems. But why do high-pressure systems not have frontal zones?&lt;/p&gt;&#xA;" OwnerUserId="6441" LastActivityDate="2017-06-19T15:41:51.087" Title="Why are frontal zones connected to low-pressure systems but not to high-pressure systems?" Tags="|synoptic|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10591" PostTypeId="2" ParentId="10564" CreationDate="2017-06-14T15:22:37.923" Score="1" Body="&lt;p&gt;I do not have the data to back this, I present this more as possible contributing points that you may be able to verify with data.  DavePhD presents an excellent and backed answer for local sea effects.  For non-local contribution, I would start with the point that warm air has the ability more total water than cold, and that if the air holds the same amount of water, but you raise its temperature, by definition, relative humidity drops.  Also, if you lower the temp, relative humidity rises, and the tendency to precipitate out that water increases.  Those are well know, just restating as a base.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a coastal location, NJ will tend to have its temperature somewhat moderated by the ocean, that is be a bit warmer in winter than it otherwise would be, and cooler in summer.  Not a lot, but a few degrees makes a difference in relative humidity.  Winter weather patterns will have a high percentage of the air mass heading at NJ coming across the continent, and a good share of the systems being arctic.  We thing of these as being wet systems, but really, they are cold systems and result in snow because they cannot hold as much moisture.  When they get to the coast, the temperature may be low as compared to summer conditions, but it may also be a bit warmer than the conditions to the West.  That rise of a couple degrees equals a drop in relative humidity for that air mass much like heating that air in your house creates very dry conditions in the winter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the summer though, as temps go up, there will also be changes in weather patterns, with a higher portion of you air masses coming from the gulf or even straight up the coast.  These will be wetter air masses.  In addition, now you are getting a cooling effect from the ocean.  Yes, temps are higher, but still a few degrees lower than they likely would have been without the ocean effect, and cooler than what they likely are to your West.  Drop the temp of the air mass a couple degrees and the relative humidity rises.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One more factor in that line, when the air mass is coming more directly from the West, or from the NW, it crosses a line of mountains before it gets to NJ, which will tend to cause more of the moisture to precipitate out.  With the summer pattern, with a bit more of the air being gulf and coastal, this misses some of the effect of NJ being on the lee side of a range.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not saying these are the cause, but logically, they likely seem to contribute to a correlation between seemingly higher humidity as temps increase.&lt;/p&gt;&#xA;" OwnerUserId="6178" LastActivityDate="2017-06-14T15:22:37.923" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10593" PostTypeId="1" CreationDate="2017-06-15T00:55:56.887" Score="3" ViewCount="1224" Body="&lt;p&gt;I believe Seismometers record ground displacement. However, I have also read in certain articles that this can be ground displacement or acceleration depending on the frequency of the seismometer. Could someone kindly elaborate on how a seismometer works.&lt;/p&gt;&#xA;" OwnerUserId="8363" LastActivityDate="2017-11-12T00:58:52.273" Title="Seismometer records ground displacement or acceleration" Tags="|earthquakes|seismology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10595" PostTypeId="1" CreationDate="2017-06-15T11:55:40.933" Score="2" ViewCount="47" Body="&lt;p&gt;I need to simulate a realtime wind's trend from his windrose distribution (made from statistical data).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How winds change direction and speed in function of time? I cannot pick a random value from that distribution because I'll simulate some unrealistic situation (Example: at minute 1, wind blows from N at 3 kn, on minute 2 wind blows from SE at 10 kn) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit n.1&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Actually i'm taking data from these datasets: &lt;a href=&quot;https://catalog.data.gov/organization/735d0118-b2a7-4246-a0e3-608b0fa8d1ec?res_format=CSV&amp;amp;tags=wind-speed&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://catalog.data.gov/organization/735d0118-b2a7-4246-a0e3-608b0fa8d1ec?res_format=CSV&amp;amp;tags=wind-speed&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8366" LastEditorUserId="8366" LastEditDate="2017-06-16T22:38:53.327" LastActivityDate="2017-06-16T22:38:53.327" Title="How to simulate wind's trend from his windrose distribution?" Tags="|wind|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10596" PostTypeId="2" ParentId="10595" CreationDate="2017-06-15T14:21:02.803" Score="3" Body="&lt;p&gt;You can't. A windrose aggregates over time, so you lose all the information about patterns over time. You're trying to do a time-based simulation, but your data source discards all time-specific information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You need a different set of data, to base your simulation on. One that contains the dimension of time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The changes in direction and speed over time vary hugely depending on the local climate and topology.&lt;/p&gt;&#xA;" OwnerUserId="100" LastActivityDate="2017-06-15T14:21:02.803" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10597" PostTypeId="1" AcceptedAnswerId="10612" CreationDate="2017-06-15T14:39:03.590" Score="2" ViewCount="86" Body="&lt;p&gt;In my book, I came across this question:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Give reason why formation of petrified tress is considered as a degradation and a sedimentation action of the underground water.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My book explains that underground water replaces the original plant material in trees with silica and other inorganic materials, and states this as a sedimentation action of underground water. But I don't understand the part of &quot;degradation action&quot; in the question, I think underground water only &lt;strong&gt;replaces&lt;/strong&gt; the plant material in trees so why we consider this to be a degradation action? Or the degradation action mentioned in the question is something else? And if yes, could you explain it for me? Thanks in advance!  &lt;/p&gt;&#xA;" OwnerUserId="6908" LastActivityDate="2017-06-18T05:50:07.697" Title="Formation of petrified trees" Tags="|sedimentology|underground-water|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10598" PostTypeId="1" AcceptedAnswerId="10631" CreationDate="2017-06-15T16:39:27.313" Score="3" ViewCount="297" Body="&lt;p&gt;I would like to use &lt;a href=&quot;https://mesonet.agron.iastate.edu/request/download.phtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;ASOS data from Iowa State University&lt;/a&gt;   to compute daily rainfall totals for specific locations. Using ASOS, I am unable to match the official NWS totals. I am assuming that the definition of a day is midnight to midnight, local time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example: &lt;a href=&quot;https://www.weather.gov/media/okx/Climate/Almanacs/LGA/lgajun.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;KLGA had a record rainfall total of 3.33&quot;&lt;/a&gt;  on June 7, 2013. An excerpt of the ASOS data covering June 7 is below. The &quot;D&quot; and &quot;H&quot; columns are EDT. It appears that rainfall totals are cumulative and reset hourly at 51 minutes (see hours 12 and 13 EDT for example). But I am unsure how to interpret certain cases. What do I do with hour 21, which reports 0.21&quot; at 36 minutes, 0 at 48 minutes, and 0.24&quot; at 49 minutes. Does that 0 denote a reset prior to 51 minutes, implying a total of 0.45&quot; for that hour? Or does it indicate something else, such as a temporary cessation?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The general questions are: a) how does one parse the p01i column, and b) should it be possible to use ASOS precipitation data to match official NWS totals? Thanks!&lt;/p&gt;&#xA;&#xA;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://mesonet.agron.iastate.edu/cgi-bin/request/asos.py?station=LGA&amp;amp;data=all&amp;amp;year1=2013&amp;amp;month1=6&amp;amp;day1=6&amp;amp;year2=2013&amp;amp;month2=6&amp;amp;day2=8&amp;amp;tz=Etc%2FUTC&amp;amp;format=comma&amp;amp;latlon=no&amp;amp;direct=no&amp;amp;report_type=1&amp;amp;report_type=2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Excerpt from ASOS data:&lt;/a&gt;&#xA;&lt;code&gt;&#xA;GMT                     M   D    H   M  p01i&#xA;...&#xA;2013-06-07T16:23:00Z    6   7   12  23  0.11&#xA;2013-06-07T16:43:00Z    6   7   12  43  0.19&#xA;2013-06-07T16:51:00Z    6   7   12  51  0.21&#xA;2013-06-07T17:35:00Z    6   7   13  35  0.18&#xA;2013-06-07T17:51:00Z    6   7   13  51  0.22&#xA;...&#xA;2013-06-08T01:16:00Z    6   7   21  16  0.18&#xA;2013-06-08T01:29:00Z    6   7   21  29  0.21&#xA;2013-06-08T01:36:00Z    6   7   21  36  0.21&#xA;2013-06-08T01:48:00Z    6   7   21  48  0&#xA;2013-06-08T01:49:00Z    6   7   21  49  0.24&#xA;2013-06-08T02:47:00Z    6   7   22  47  0.22&#xA;2013-06-08T02:51:00Z    6   7   22  51  0.22&#xA;2013-06-08T03:51:00Z    6   7   23  51  0.11&#xA;2013-06-08T03:58:00Z    6   7   23  58  0&#xA;&lt;/code&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt; See below. Note that the value of p01i at 6:59 (0.01&quot;) is less than that at 6:51 (0.05&quot;), and greater than that at 7:40 (0&quot;), which in turn is less than that at 7:51 (0.09&quot;). What exactly is being reported here? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;code&gt;&#xA;GMT                     M   D   H    M  p01i&#xA;2013-06-07T10:51:00Z    6   7   6   51  0.05&#xA;2013-06-07T10:59:00Z    6   7   6   59  0.01&#xA;2013-06-07T11:40:00Z    6   7   7   40  0&#xA;2013-06-07T11:51:00Z    6   7   7   51  0.09&#xA;&lt;/code&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit #2&lt;/strong&gt;: @JeopardyTempest  confirms the importance of 51 minutes past the hour. I have an algorithm that (almost!) works. Assume:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The day is measured from midnight to midnight local time, &lt;em&gt;without&lt;/em&gt; a DST adjustment. So in June, LGA remains at -0500.&lt;/li&gt;&#xA;&lt;li&gt;Precipitation totals are accumulated to 51 minutes each hour&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.wunderground.com/history/airport/KLGA/2013/6/16/MonthlyHistory.html?req_city=KLGA&amp;amp;req_state=NY&amp;amp;req_statename=New+York&amp;amp;reqdb.zip=11371&amp;amp;reqdb.magic=5&amp;amp;reqdb.wmo=99999&amp;amp;MR=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;The official daily 2013 rainfall totals for June 2, 3, 6, and 7&lt;/a&gt; are 0.11, 0.96, 0.10, 3.33, 0.79. Using the algorithm above with the ASOS data for the same days yields 0.11, 0.96, 0.10, 3.32, 0.80.&lt;/p&gt;&#xA;" OwnerUserId="8368" LastEditorUserId="8368" LastEditDate="2017-06-20T03:40:09.533" LastActivityDate="2017-06-20T03:47:22.763" Title="How are daily precipitation totals computed?" Tags="|meteorology|measurements|precipitation|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10599" PostTypeId="2" ParentId="10588" CreationDate="2017-06-15T16:59:49.257" Score="2" Body="&lt;p&gt;The (relatively) easy answer is that the mechanism that low pressure systems generally form are different than the mechanism that high pressure areas form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This begs the question &quot;How do low pressure systems form?&quot; I'll label the steps of the &quot;Norwegian Cyclone Model&quot; in brief layman-speak.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;First you need an area where temperatures change drastically with distance, generally with cold air to the north, and warm air to the south.&lt;/li&gt;&#xA;&lt;li&gt;Up high in the atmosphere, a small disturbance of winds push the cold air towards the warm air (creating a cold front) and the warm air towards the cold air (creating a warm front).&lt;/li&gt;&#xA;&lt;li&gt;As the warm air advances, the pressure decreases.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;High pressure areas, however, have a different formation process, one the involves converging winds and cooling. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In brief: low pressure systems have fronts because (generally) the creation of low pressure systems require differences in temperature. High pressure areas do not- they need different &quot;ingredients.&quot;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-06-15T16:59:49.257" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10600" PostTypeId="1" AcceptedAnswerId="10601" CreationDate="2017-06-15T20:41:27.347" Score="1" ViewCount="151" Body="&lt;p&gt;From &lt;a href=&quot;https://en.wikipedia.org/wiki/Extinction_event#A_nearby_nova.2C_supernova_or_gamma_ray_burst&quot; rel=&quot;nofollow noreferrer&quot;&gt;this subsection&lt;/a&gt; in Wikipedia's aricle on &lt;a href=&quot;https://en.wikipedia.org/wiki/Extinction_event&quot; rel=&quot;nofollow noreferrer&quot;&gt;extinction event&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A nearby gamma-ray burst (less than 6000 light years away) would be powerful enough to destroy the Earth's ozone layer, leaving organisms vulnerable to ultraviolet radiation from the sun.[92] Gamma ray bursts are fairly rare, occurring only a few times in a given galaxy per million years.[93] It has been suggested that a supernova or gamma ray burst caused the End-Ordovician extinction.[94]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Does this mean if this were to occur it would take 6000 years for the gamma ray burst to destroy our ozone (potentially)?&lt;/p&gt;&#xA;" OwnerUserId="8369" LastEditorUserId="6031" LastEditDate="2017-06-17T08:32:02.073" LastActivityDate="2017-06-17T08:32:02.073" Title="gamma ray burst, extinction-level event" Tags="|earth-history|ozone|mass-extinction|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10601" PostTypeId="2" ParentId="10600" CreationDate="2017-06-16T02:24:21.927" Score="3" Body="&lt;p&gt;As bon noted in the comments, that it the time it would take the gamma rays to reach Earth. Gamme rays travel at the same speed as all other forms of electromagnetic radiation, including visible light, so we will not have any warning. This kind of makes the &quot;6000&quot; number meaningless. We will know that the star exploded and the gamme rays will reach earth at the same time. The destruction of ozone will then probably be instantaneous (on a geological time scale).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From your quote:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It has been suggested that a supernova or gamma ray burst caused the End-Ordovician extinction.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It has been suggested because there was no other plausible terrestrial cause for the mass extinction, so people started to look at extra-terrestrial causes. But a paper published earlier this year documents a mercury anomaly associated with the extinction event. This gives strong evidence for a volcanic cause for the extinction (similar to the P-T or K-Pg events), and there is no need to make up a gamma-ray burst.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;David S. Jones, Anna M. Martini, David A. Fike, and Kunio Kaiho: A volcanic trigger for the Late Ordovician mass extinction? Mercury data from south China and Laurentia. Geology, July 2017, v. 45, p. 631-634, 2017, doi:&lt;a href=&quot;http://dx.doi.org/10.1130/G38940.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.1130/G38940.1&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-06-16T02:24:21.927" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10604" PostTypeId="1" CreationDate="2017-06-16T17:49:17.393" Score="1" ViewCount="83" Body="&lt;p&gt;Where can I send a sample of material to be tested to see exactly what it is?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do you have an address where items can be sent for testing and evaluation?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have a softball size rock that was given to me by my father some 50 years ago and the story that goes with it is awsome if true and would make this a great item to be passed down from generation to generation as a keepsake. (But only if I can verify the rock.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to try and validate the material and the story just for my own satisfaction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't have a lot of money so if you know of someone or somewhere I could send a sample for testing and evaluation I would greatly appreciate it.&lt;/p&gt;&#xA;" OwnerUserId="8376" LastEditorDisplayName="user12525" LastEditDate="2019-09-05T14:18:21.007" LastActivityDate="2019-09-05T14:18:21.007" Title="Where can I get mineral testing done?" Tags="|mineralogy|petrology|" AnswerCount="2" CommentCount="3" ClosedDate="2019-09-09T19:55:08.990" ContentLicense="CC BY-SA 3.0" />
  <row Id="10605" PostTypeId="2" ParentId="10588" CreationDate="2017-06-16T19:07:32.827" Score="7" Body="&lt;p&gt;&lt;strong&gt;Not only are fronts associated with (extratropical) lows, but by in large, fronts are &lt;em&gt;extensions&lt;/em&gt; of those lows&lt;/strong&gt;, as shown by the following &lt;a href=&quot;http://www.spc.noaa.gov/exper/surfaceMaps/&quot; rel=&quot;nofollow noreferrer&quot;&gt;hand analysis&lt;/a&gt; (&lt;a href=&quot;http://www.spc.noaa.gov/faq/tornado/sfcanls.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;from the US Storm Prediction Center&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yRe8D.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yRe8D.jpg&quot; alt=&quot;Analysis&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's a lot going on in the image, but try to focus on the many black lines, which show pressure: they're kinked around each front (and even the dryline).  This indicates that the pressure is higher on either side of the front.  (for another good example: &lt;a href=&quot;http://www.weather.gov/images/ilm/climate/Superstorm93/SurfaceMap_anim.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;this set of images&lt;/a&gt; from the 1993 Storm of the Century from the &lt;a href=&quot;http://www.weather.gov/images/ilm/climate/Superstorm93/SurfaceMap_anim.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Weather Service&lt;/a&gt;).  Now the kinks in these drawings aren't caused by the actual layout of observation in the image, but added by the understanding of the meteorologist performing the analysis.  Generally observation sites are too widely spread out to see the small pressure kinks.  However, they do sometimes show up in high-resolution numerical weather models forecasts, even despite not being in the initial observation data they run from:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gfUS6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gfUS6.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;(From Hartung as indicated... note that the kinks are up instead of down, but that's actually the same result, still pointing away from the low, showing lower pressure at the center of the kinks.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Though pressure troughs can be spatially hard to see without extremely dense observation networks, they can be made out instead in temporal plots at single locations.  After all, falling pressure has been noticed as a sign of bad weather as far back as the the dawn of America (I often hear Benjamin Franklin cited, but it appears it goes back further to &lt;a href=&quot;https://en.wikipedia.org/wiki/Otto_von_Guericke#Relevant_research&quot; rel=&quot;nofollow noreferrer&quot;&gt;Otto von Guericke&lt;/a&gt; in the 1600s).  For example, this trace of temperature and pressure from a 1911 cold front in Louisville, Kentucky:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TDS9a.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TDS9a.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;sup&gt;&lt;sub&gt;(source: &lt;a href=&quot;https://www.weather.gov/lmk/nov_11_1911_cold_front&quot; rel=&quot;nofollow noreferrer&quot;&gt;Louisville NWS&lt;/a&gt;)&lt;/sub&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;hr&gt;&#xA;&lt;strong&gt;So, WHY are fronts low pressure areas?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It goes to its nature in connection to winds.  Consider the images below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7aFoz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7aFoz.png&quot; alt=&quot;a developing front&quot;&gt;&lt;/a&gt;&#xA;&lt;sub&gt;&lt;sup&gt;(ETA images courtesy of Iowa State's &lt;a href=&quot;http://mtarchive.geol.iastate.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;MTArchive&lt;/a&gt;)&lt;/sup&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The plots are two days apart.  So how do you get the conditions to change from the left image to the right over such a period?  While clouds, storms, and sunlight differences can help drive small contrasts, the only way to get such a large, widespread boundary... is to have winds develop that draw the contrasting temperatures tighter together...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5SiLX.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5SiLX.png&quot; alt=&quot;a developing front: why&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Indeed, this is exactly what forms and sustains a front.  You can look at surface weather maps and almost always see this &lt;strong&gt;convergence&lt;/strong&gt;, or gathering together of winds, at fronts, even if only slight, as indicated in this idealized diagram set:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VFgjJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VFgjJ.png&quot; alt=&quot;![![![frontwinds&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;(Image modified from &lt;a href=&quot;http://okfirst.mesonet.org/train/meteorology/Fronts.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;OKFirst&lt;/a&gt;, the education arm of the &lt;a href=&quot;http://www.mesonet.org&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oklahoma Mesonet program&lt;/a&gt;.  See comments for modifications I made.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The thing is, there's only a &lt;a href=&quot;http://www.theweatherprediction.com/habyhints/134/&quot; rel=&quot;nofollow noreferrer&quot;&gt;few basic forces&lt;/a&gt; that drive wind formation... and in the lower atmosphere, it turns out that the pressure gradient force outweighs the others enough such that, on the large-scale, &lt;strong&gt;air always flows from higher pressure towards lower pressure&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if you put those two ideas together:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;To create/strengthen/sustain a front, you need wind converging together&lt;/li&gt;&#xA;&lt;li&gt;Air at low-levels flows from high pressure to low pressure...&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The resulting conclusion is that the location where winds are flowing together... which is the front itself... must be a low pressure area.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(What causes low formation in the first place?&lt;br&gt;&#xA;Winds aloft typically coupled with terrain enhancements or other small-scale perturbations.  The strengthening temperature gradients actually feedback to intensify and favorably realign the winds aloft... such that, despite the influx of air into the low pressure (which one might think would &quot;fill in&quot; the low pressure with more air, dimi), the air is actually ventilated from the system, allowing it to deepen to yet lower pressures values and strengthen further... continuing on until finally the upper-level storm system surges ahead of the surface low and/or the frontal boundary occludes, cutting warm air from continuing to flow into the surface low center.)&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Can you get divergent winds near a developed front?&lt;br&gt;&#xA;Yes... in fact, there's a name for that process, it's called &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Frontolysis&quot; rel=&quot;nofollow noreferrer&quot;&gt;frontolysis&lt;/a&gt;. Divergent wind does indeed work to destroy a frontal gradient.  And so rising pressure is found connected to dissipating fronts.  However, rising pressure has a long ways to go before it's actually a high pressure itself!  Long before it would create a bona fide high, the early pressure rises only REDUCE the strength of that local pressure minimum... and during that time the temperature gradient will very quickly begin to blur out and fall below the strength of which we really notice.  At the same time, even in this period of decrease, note that this dissipating &quot;front&quot; would no longer have any of the other typical conditions we expect with fronts (no more &lt;a href=&quot;https://www.atmos.illinois.edu/~snodgrss/Midlatitude_cyclone_files/image016.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;rising air motions&lt;/a&gt; &lt;sub&gt;&lt;sup&gt;[&lt;a href=&quot;https://www.atmos.illinois.edu/~snodgrss/Midlatitude_cyclone.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;UIllinois&lt;/a&gt;]&lt;/sup&gt;&lt;/sub&gt;, which is what in turn creates the unsettled weather, clouds, strong winds, storms, etc).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is a front so quick to dissipate?  Well, in large part because it's not a level situation; indeed, some storm energy is continually lost away to friction.  Because of this, &lt;strong&gt;a front actually needs continual reinforcement to even maintain its gradient&lt;/strong&gt;.  Some times the pattern will permit fronts to continue through repeated periods of weakening and intensification as upper troughs pass by.  As a trough comes by and then shifts by on east (in tandem with the primary surface low), the front will start to weaken some... perhaps gradually becoming stationary... only to reignite when the next upper system comes in from the west [stationary fronts aren't, as may often be suggested, a cold front and warm front &quot;at war&quot;, but instead rather more like a lull in the &quot;battle&quot;, where the cold front has run out of steam, but readied next for the warm air to start surging back north should another trough/low move in to re-fire the convergence].  Often you can see quite a long chain of fronts (troughs) connecting together lows pressure systems &lt;a href=&quot;http://www.wpc.ncep.noaa.gov/dailywxmap/index_20170204.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;across continents&lt;/a&gt;... (&lt;a href=&quot;http://atoc.colorado.edu/~dcn/ATOC5050/lectures/13_ThermalWind.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;which work into the shape and positioning to the polar jet stream&lt;/a&gt;).  Other times, when the upper systems come less consistently or the upper flow starts to break down/shift into other regions, the front will quickly fade from existence.  So much so that &lt;strong&gt;I don't believe you're ever not going to see anything like a true front anywhere near a formative synoptic high pressure... unless maybe a giant meteor or as-of-yet-unseen-in-size nuclear bomb were precisely set loose upon a front.  And then... well I suggest trying to witness the brief time that the high pressure is connected to the frontal boundaries... should probably be the least of your concerns!&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Of course an important note is that &lt;strong&gt;not all lows have fronts&lt;/strong&gt;, not nearly.  Only &quot;extratropical&quot; (baroclinic, cold-core) lows have fronts.  Tropical (barotropic, warm-core) lows are symmetrical, and don't generate their energy from horizontal temperature imbalances, but instead when overall warming temperature, typically in the mid-levels, decreases the amount of air in the entire tropospheric column...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Y3INU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Y3INU.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;sub&gt;&lt;sup&gt;Found on the &lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/A7.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;AOML&lt;/a&gt;, but originally adapted from Merrill, R. T., (1993): &quot;Tropical Cyclone Structure&quot; - Chapter 2, Global Guide to Tropical Cyclone Forecasting, WMO/TC-No. 560, Report No. TCP-31, World Meteorological Organization; Geneva, Switzerland&lt;/sup&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And for those of you better versed in the more rigorous science... while looking for material for this answer, I came across an absolutely great resource that may prove helpful to those looking to dig much more at the mathematical formulations of frontogensis/frontolysis, the consequential flow types involved in them, and how they impact forecasting: &lt;a href=&quot;http://www.wdtb.noaa.gov/courses/winterawoc/documents/color_PDFs/IC52.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this awesome guide from NOAA's Warning Decision Training Branch&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-06-19T15:41:51.087" LastActivityDate="2017-06-19T15:41:51.087" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10606" PostTypeId="2" ParentId="10436" CreationDate="2017-06-16T19:38:12.097" Score="3" Body="&lt;p&gt;While the horizontal alignment of ice crystals has been observed in several previous studies listed in the Marshak et al. paper, it is not clear how much ice crystals wobble around the perfectly horizontal position. Determining the range of tilt angles would be very interesting indeed! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason why ice plates can float with a horizontal alignment is discussed in the 1998 article &quot;&lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469%281998%29055%3C3358%3ASALRNF%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Subsuns and Low Reynolds Number Flow&lt;/a&gt;” by J. I. Katz, 1998, (Journal of Atmospheric Sciences, Volume 55, 3358). The article includes the following paragraph:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Under what conditions will a small, thin falling plate of ice maintain&#xA;  an accurately horizontal orientation? At high Reynolds number Re &gt; 1 a&#xA;  falling plate leaves a turbulent wake (Willmarth et al. 1964;&#xA;  Pruppacher and Klett 1978). Its center of drag lies close to its&#xA;  leading edge or surface; any steady orientation is unstable; it&#xA;  tumbles, and its path is irregular because of large horizontal forces&#xA;  arising during its tumbling (ice crystals, unlike airplanes, rockets,&#xA;  and arrows, are not equipped with stabilizing tails!). This is readily&#xA;  verified by dropping a penny into a jar of water, an experiment in&#xA;  which Re ≈ 3000; it tumbles and usually hits the sides. For Re ≈ 100 a&#xA;  falling disc may oscillate periodically about a horizontal orientation&#xA;  as it leaves behind a regular vortex street. This may be seen by&#xA;  dropping aluminum foil discs of various radii into water. At Re &amp;lt; 100,&#xA;  however, tumbling and oscillations are strongly damped by viscosity.&#xA;  Intuitive concepts from our everyday experience with high Re flows are&#xA;  still qualitatively applicable and show that a vertical orientation&#xA;  (edge on to the flow) is unstable; if the plate tilts the hydrodynamic&#xA;  force on its leading edge acts to amplify the tilt. However, the&#xA;  horizontal orientation (face on to the flow) is stable; if the plate&#xA;  tilts the wake of the leading edge partly shields the trailing edge&#xA;  from the flow, reducing the drag on it; the resulting torque restores&#xA;  the horizontal orientation and the disturbance is quickly damped.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="8378" LastEditorUserId="6031" LastEditDate="2017-06-17T02:46:55.787" LastActivityDate="2017-06-17T02:46:55.787" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10607" PostTypeId="2" ParentId="10598" CreationDate="2017-06-16T20:27:23.947" Score="2" Body="&lt;p&gt;Typical synoptic (hourly) obs come in about 51 past the hour (sometimes a couple minutes off).  The other reports you're seeing are generally subops (SPECIs) which generally only report precip since the last ob given, but the total of which should always be reflected in the hourly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So for 2136/2148/2149 timed obshour... you just use the 0.24 from 2149, and it should include the others in it (so skip the others that would lead to double-counting).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, the 659 ob being smaller than the 651 ob makes sense... as 659 is in the NEW hour... so would be reflected in the 751 ob (which is indeed higher).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I didn't get a chance to look too closely, but looks like all of these are unfortunately altered forms of the data.  I believe typical full data should have METAR or SPECI in it to indicate which obs you want?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But no big deal, if you look back at &lt;a href=&quot;https://mesonet.agron.iastate.edu/cgi-bin/request/asos.py?station=LGA&amp;amp;data=all&amp;amp;year1=2013&amp;amp;month1=6&amp;amp;day1=6&amp;amp;year2=2013&amp;amp;month2=6&amp;amp;day2=8&amp;amp;tz=Etc%2FUTC&amp;amp;format=comma&amp;amp;latlon=no&amp;amp;direct=no&amp;amp;report_type=1&amp;amp;report_type=2&quot; rel=&quot;nofollow noreferrer&quot;&gt;the rawer-looking data you gave&lt;/a&gt;, looks like you can find which ones you want by looking for the ones with SLP reported right about the end.  Or, even better, just look for the 6**** fields right about the end, which are the 6 hour total precipitation.  Just add the four of those up, and you'll have the daily total.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you're trying to accomplish all this in Excel, some formulas could be worked up to automatically take what you need from the day's data, or you could use a regex in &lt;a href=&quot;https://regex101.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;any&lt;/a&gt; of the variety of online regex testers.  Or writing some sort of script could save a lot of time if you're downloading a lot of data.  But the rawer data is often safer and more easy to work with.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think I used a page like &lt;a href=&quot;http://www.met.tamu.edu/class/metar/quick-metar.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; for more info back in the day when I had to do it.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-06-17T12:31:40.520" LastActivityDate="2017-06-17T12:31:40.520" CommentCount="13" ContentLicense="CC BY-SA 3.0" />
  <row Id="10608" PostTypeId="2" ParentId="10604" CreationDate="2017-06-17T01:51:39.160" Score="3" Body="&lt;p&gt;It depends on what type of test. If you just want simple identification this site offers a tentative one and any museum with a mineralogy section will have someone on staff who can do identification and they are usually happy to do it. Ditto for an college with a geology class/program. you might want to call/email the professor in question first to make sure they are willing. All these are usually free, although for the museum you should at least pay the admittance fee out of courtesy. You can also look for a local rockhound club.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2017-06-17T01:51:39.160" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10609" PostTypeId="2" ParentId="10604" CreationDate="2017-06-17T03:01:41.393" Score="1" Body="&lt;p&gt;If it's a sample of sentimental value, you probably do not want to have the material &quot;tested&quot;. Mineral testing methods such as &lt;a href=&quot;https://serc.carleton.edu/research_education/geochemsheets/techniques/XRD.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;XRD&lt;/a&gt;, &lt;a href=&quot;https://serc.carleton.edu/research_education/geochemsheets/techniques/XRF.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;XRF&lt;/a&gt;, &lt;a href=&quot;https://serc.carleton.edu/research_education/geochemsheets/eds.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;EDS&lt;/a&gt;, LA, petrography, etc are destructive to one degree or another. These methods are also usually expensive, unless you story is compelling enough to convince someone to do it for free.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alternatively, I would recommend following the advice of John. Just find a geologist and ask them. An easy place to start would be here: we have a &lt;a href=&quot;https://earthscience.meta.stackexchange.com/a/125/725&quot;&gt;guide for asking identification&lt;/a&gt; questions. Just ask here, and see how that goes. You can also include the background story, if you think it will help us identify or get our opinion whether or not it is consistent with what we think the rock is.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-06-17T03:01:41.393" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10611" PostTypeId="1" AcceptedAnswerId="10639" CreationDate="2017-06-18T05:37:27.937" Score="5" ViewCount="1164" Body="&lt;p&gt;I'd like to make a &lt;a href=&quot;https://en.wikipedia.org/wiki/Anemometer#Ping-pong_ball_anemometers&quot; rel=&quot;nofollow noreferrer&quot;&gt;ping-pong ball anemometer&lt;/a&gt; to make estimates or approximate measurements of wind and surface air currents at low to moderate speeds. I don't own an anemometer now, but I'd estimate the speeds of interest to be between zero and a maximum of order of 10 or 15 mph (feels similar to riding a (non-racing) bicycle down hill on an otherwise windless day).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I understand correctly, a ping-pong ball anemometer probably refers to the use of a ping-pong ball or other &lt;a href=&quot;https://en.wikipedia.org/wiki/Tell-tale&quot; rel=&quot;nofollow noreferrer&quot;&gt;tell-tale&lt;/a&gt; normally used to indicate wind direction to &lt;em&gt;also try to use it&lt;/em&gt; to estimate the speed of the wind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this were a problem on a test, I'd set up the equations for force and balance the vertical and horizontal forces separately, assuming the wind is horizontal. For the horizontal force, I'd use a simple equation for drag force as a function of velocity from &lt;a href=&quot;https://en.wikipedia.org/wiki/Drag_(physics)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$F_D(v)= \frac{1}{2} \rho v^2 C_D A$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where the &lt;a href=&quot;https://en.wikipedia.org/wiki/Density_of_air&quot; rel=&quot;nofollow noreferrer&quot;&gt;density of air at low elevations and moderate temperature&lt;/a&gt; is roughly 1.2 kg/m^3, &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; is the cross-sectional area of the ping-pong ball &lt;span class=&quot;math-container&quot;&gt;$\pi R_{p-pb}^2$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$C_D$&lt;/span&gt; would be the &lt;a href=&quot;https://en.wikipedia.org/wiki/Drag_coefficient&quot; rel=&quot;nofollow noreferrer&quot;&gt;drag coefficient&lt;/a&gt;, which is where all of the reality and the complications of aerodynamics are actually hidden in practice. &lt;span class=&quot;math-container&quot;&gt;$C_D$&lt;/span&gt; is not really a constant, and is often &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Drag_coefficient_on_a_sphere_vs._Reynolds_number_-_main_trends.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;plotted against velocity&lt;/a&gt; and other parameters. However, for some range of &lt;a href=&quot;https://en.wikipedia.org/wiki/Reynolds_number&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reynolds numbers&lt;/a&gt;, a perfect sphere would have a roughly constant &lt;span class=&quot;math-container&quot;&gt;$C_D$&lt;/span&gt; &lt;a href=&quot;https://en.wikipedia.org/wiki/Drag_coefficient&quot; rel=&quot;nofollow noreferrer&quot;&gt;of about 0.47&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But a &lt;a href=&quot;https://en.wikipedia.org/wiki/Table_tennis#Ball&quot; rel=&quot;nofollow noreferrer&quot;&gt;2.7 gram, 40mm diameter ping-pong ball&lt;/a&gt; anemometer, or similar device is a real-world device. Maybe I should use a heavier ball, but I think the smoothness of the ball is critical if I want to use a theoretical &lt;span class=&quot;math-container&quot;&gt;$C_D$&lt;/span&gt; and estimate speeds using equations rather than doing a real calibration against a known anemometer or riding in/on a vehicle at a known speed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any instructions for how to build, use, and calibrate or interpret results for this kind of simple anemometer? Ideally some dimensions and a suggested scale would be great! Or if this has been actually measured for a pingpong ball or another object, that would also be a great answer as well.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;If &lt;a href=&quot;https://en.wikipedia.org/wiki/Tell-tale#Space&quot; rel=&quot;nofollow noreferrer&quot;&gt;the concept&lt;/a&gt; is good enough for a &lt;a href=&quot;https://space.stackexchange.com/q/21680/12102&quot;&gt;Mars lander weather station&lt;/a&gt;, then it's good enough for me!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FJbPa.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FJbPa.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; GIF from images transmitted from Mars. From the &lt;a href=&quot;http://marslab.au.dk/research/instrument-development/the-telltale-project/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Telltale project&lt;/a&gt; page on the &lt;a href=&quot;http://marslab.au.dk/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mars Simulation Laboratory&lt;/a&gt;. Also &lt;a href=&quot;https://web.archive.org/web/20120220080017/http://www.marslab.dk/TelltaleProject.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;archived here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xCWAk.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xCWAk.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; Instrument as delivered to NASA. From the &lt;a href=&quot;http://marslab.au.dk/research/instrument-development/the-telltale-project/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Telltale project&lt;/a&gt; page on the &lt;a href=&quot;http://marslab.au.dk/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mars Simulation Laboratory&lt;/a&gt;. Also &lt;a href=&quot;https://web.archive.org/web/20120220080017/http://www.marslab.dk/TelltaleProject.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;archived here&lt;/a&gt;. That's a 45 degree mirror below the telltale providing a simultaneous view from below.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2018-12-14T23:29:46.390" LastActivityDate="2018-12-14T23:29:46.390" Title="How to make, read, and calibrate a ping-pong ball anemometer?" Tags="|measurements|wind|field-measurements|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="10612" PostTypeId="2" ParentId="10597" CreationDate="2017-06-18T05:50:07.697" Score="0" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;But I don't understand the part of &quot;degradation action&quot; in the question, I think underground water only replaces the plant material in trees...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Degradation refers to the process of aqueous dissolution of the organic materials; the fact is, organic materials are generally quickly dissolved after the death of a living organism...degraded into nothing before the fossilization process can even start. (Think of the carbon cycle and how organic compounds are re-used over and over again over the eons of life on this planet.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's a bit of a misnomer in this case because it ignores the simultaneous replacement of that organic matter with inorganic siliceous materials. &lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-06-18T05:50:07.697" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10613" PostTypeId="2" ParentId="239" CreationDate="2017-06-18T09:00:32.567" Score="7" Body="&lt;p&gt;The Coriolis effect is necessary for FORMATION but NOT for MAINTENANCE of a tropical cyclone. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once formed, in a full-fledged tropical cyclone of hurricane intensity the wind balance is cyclostrophic, between the pressure-gradient and centrifugal force, with the Coriolis effect negligible by comparison. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is especially true if the tropical cyclone is small but intense. Thus a full-fledged tropical cyclone of hurricane intensity would encounter NO difficulty if it crossed the equator. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Its circulation would be classified as baric before crossing the equator and antibaric afterwards. Thus a full-fledged tropical cyclone of hurricane intensity will NOT weaken upon crossing the equator due to the reversed Coriolis effect (although it may weaken or strengthen due to other causes). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;An antibaric cyclone is fully consistent with the laws of motion. Except on the smallest scales such as dust devils or whirlpools it is difficult to initiate, but once initiated it can be stable. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A tropical cyclone crossing the equator may be the only way that a synoptic-scale antibaric cyclone can be initiated. If a tropical cyclone, especially a large one, crosses the equator and attains appreciable latitude in the opposite hemisphere, say the outer tropics or lower middle latitudes, then the gradient wind approximation rather than the cyclostrophic wind approximation is applicable. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But antibaric gradient wind is still a stable flow. See for example James R. Holton and Gregory J. Hakim, Dynamic Meteorology Fifth Edition Section 3.2.5 on pp. 74-77. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In baric gradient flow the Coriolis and centrifugal forces acting outwards balance the pressure-gradient force acting inwards. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In antibaric flow the centrifugal force acting outwards balances the pressure gradient and Coriolis forces acting inwards. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus for a given pressure gradient and radius of curvature of the isobars, the centrifugal force must be stronger, and hence the wind speed higher, for an antibaric tropical cyclone than for a baric one. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This does not mean that a tropical cyclone must intensify if it crosses the equator. Whether baric or anitbaric, its intensity is determined by the available energy or exergy corresponding to the sea-surface and tropopause temperatures (with possible deductions for wind shear, entrainment of dry air, land interaction, etc.) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The First and Second Laws of Thermodynamics require that the pressure gradient and radius of curvature of the isobars must adjust to the exergy supply --- not vice versa. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to Holton and Hakim, an antibaric (synoptic-scale) hurricane can easily exist if it is centered say only a few degrees from the Equator in the opposite hemisphere, but this becomes more and more difficult and hence more and more unlikely with increasing latitude in the opposite hemisphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whether at some latitude in the opposite hemisphere it becomes absolutely impossible may be an open question. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Small-scale antibaric cyclones (dust devils, whirlpools, waterspouts, and to a lesser extent tornadoes) can easily exist at any any latitude where sufficient exergy exists to generate and maintain them.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastEditorUserId="568" LastEditDate="2017-12-07T07:42:11.103" LastActivityDate="2017-12-07T07:42:11.103" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="10614" PostTypeId="1" AcceptedAnswerId="10615" CreationDate="2017-06-18T18:00:47.470" Score="2" ViewCount="106" Body="&lt;p&gt;My text books says that the residual soil shows a similarity in its chemical composition to the original rock beneath it, and that the degree of similarity differs by differing &lt;em&gt;the influence type of atmosphere&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't get the part of &quot;differing the influence type of atmosphere.&quot; Do you have any ideas?&lt;/p&gt;&#xA;" OwnerUserId="6908" LastEditorUserId="6908" LastEditDate="2017-06-18T20:46:55.563" LastActivityDate="2020-11-01T18:47:26.100" Title="Reisdual soil and the atmosphere influence" Tags="|soil|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10615" PostTypeId="2" ParentId="10614" CreationDate="2017-06-18T19:55:59.607" Score="0" Body="&lt;p&gt;The &lt;em&gt;influence type of atmosphere&lt;/em&gt; could refer to a variety of things that affect soil properties such as: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;rainfall&lt;/li&gt;&#xA;&lt;li&gt;wind&lt;/li&gt;&#xA;&lt;li&gt;deposition of chemical species (e.g. nitrates, sulfates, carbon species, etc.)&lt;/li&gt;&#xA;&lt;li&gt;heating/cooling &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-06-18T19:55:59.607" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10616" PostTypeId="2" ParentId="10614" CreationDate="2017-06-19T02:32:14.647" Score="1" Body="&lt;p&gt;If you are including the early history of the earth, study of regolith from the Archean period has been used to indicate the oxidation state of the atmosphere. Different weathering products form, depending on the amount of oxygen in the air and dissolved in infiltrating rainwater. So the residual soil chemical and isotopic composition changed when the atmosphere became oxic. There are a few locations in South Africa, Canada, and probably other places where these soils were buried and preserved, (e.g. by lava flows near Flin Flon Manitoba Canada). &lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-06-19T02:32:14.647" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10617" PostTypeId="1" AcceptedAnswerId="14439" CreationDate="2017-06-19T05:23:54.917" Score="7" ViewCount="988" Body="&lt;p&gt;&lt;strong&gt;update:&lt;/strong&gt; Searching &amp;quot;Rub' al Khali Empty Quarter&amp;quot; found &amp;quot;Q2: What are sabkhas?&amp;quot; in&#xA;&lt;a href=&quot;https://www.geocaching.com/geocache/GC6BYQ0_rub-al-khali-the-empty-quarter&quot; rel=&quot;noreferrer&quot;&gt;https://www.geocaching.com/geocache/GC6BYQ0_rub-al-khali-the-empty-quarter&lt;/a&gt; which seems to be related.&lt;/p&gt;&#xA;&lt;p&gt;From the &lt;a href=&quot;https://www.nasa.gov/multimedia/imagegallery/image_feature_1200.html&quot; rel=&quot;noreferrer&quot;&gt;NASA image gallery&lt;/a&gt;; and also &lt;a href=&quot;https://photojournal.jpl.nasa.gov/catalog/PIA11084&quot; rel=&quot;noreferrer&quot;&gt;Catalog Page for PIA11084&lt;/a&gt; where the caption says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Original Caption Released with Image:&lt;/strong&gt; The Rub' al Khali is one of the largest sand deserts in the world, encompassing most of the southern third of the Arabian Peninsula. It includes parts of Oman, United Arab Emirates, and Yemen. The desert covers 650,000 square kilometers, more than the area of France. Largely unexplored until recently, the desert is 1000 km long and 500 km wide. The first documented journeys made by Westerners were those of Bertram Thomas in 1931 and St. John Philby in 1932. With daytime temperatures reaching 55 degrees Celsius, and dunes taller than 330 meters, the desert may be one of the most forbidding places on Earth.&lt;/p&gt;&#xA;&lt;p&gt;The image was acquired December 2, 2005, covers an area of 54.8 x 61.9 km, and is located near 20.7 degrees north latitude, 53.6 degrees east longitude.&lt;/p&gt;&#xA;&lt;p&gt;The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Image Credit:&lt;/strong&gt; NASA/GSFC/METI/ERSDAC/JAROS, and U.S./Japan ASTER Science Team&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Image Addition Date:&lt;/strong&gt; 2008-08-08&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; The pattern shown in this image has an amazing amount of approximate repetition of shapes; long straight segments with a periodicity of about 2 kilometers, &amp;quot;stair steps&amp;quot; &lt;em&gt;northward&lt;/em&gt; and sharp, pointy extensions &lt;em&gt;southward&lt;/em&gt;. Is there any understanding how such a distinct pattern could be formed?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; &amp;quot;Rub' al Khali (Arabian Empty Quarter) sand dunes imaged by Terra (EOS AM-1)&amp;quot; cropped and full sized (reduced resolution) images from &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Rub%27_al_Khali_(Arabian_Empty_Quarter)_sand_dunes_imaged_by_Terra_(EOS_AM-1).jpg&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wFVhj.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wFVhj.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tVoGs.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tVoGs.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; screen shot from Google Maps confirming orientation. Marker is at &lt;code&gt;20.7N, 53.6E&lt;/code&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Jel5i.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Jel5i.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6298" LastEditDate="2022-02-06T17:23:29.127" LastActivityDate="2022-02-06T17:23:29.127" Title="What produces these distinct shapes in the Rub' al Khali seen from space?" Tags="|geography|geomorphology|satellites|satellite-oddities|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10618" PostTypeId="1" CreationDate="2017-06-19T06:14:14.823" Score="2" ViewCount="90" Body="&lt;p&gt;Coastlines are highly fractal, leading to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Coastline_paradox&quot; rel=&quot;nofollow noreferrer&quot;&gt;coastline paradox&lt;/a&gt;: the length increases to surprisingly large numbers as your scale of measurement gets smaller.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does the same thing apply to rivers, or is there some mechanism that keeps their lengths reasonably finite?&lt;/p&gt;&#xA;" OwnerUserId="2643" LastEditorUserId="2536" LastEditDate="2017-06-19T07:15:24.863" LastActivityDate="2017-06-19T09:23:46.220" Title="Does the length of a river depend on the scale of measurements?" Tags="|measurements|geography|rivers|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10619" PostTypeId="1" CreationDate="2017-06-19T07:13:59.790" Score="8" ViewCount="976" Body="&lt;p&gt;Northern Australia receives substantial rainfall, but its population is minimal. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For instance the Kimberley region in the state of Western Australia gets more than 20 in. of rainfall per year, but has a population density of less than 1 person per 3 sq. mi.(!) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a reason northern Australia is unattractive for human habitation and agriculture?&lt;/p&gt;&#xA;" OwnerUserId="8385" LastEditorUserId="6703" LastEditDate="2017-06-19T10:53:04.700" LastActivityDate="2017-06-20T04:35:56.793" Title="Why is northern Australia unsuitable for agriculture?" Tags="|meteorology|soil|rainfall|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10620" PostTypeId="2" ParentId="10618" CreationDate="2017-06-19T09:23:46.220" Score="2" Body="&lt;p&gt;The same problem applies to all shapes that are complex and this includes coastlines, rivers and the perimeters of leaves. Most shapes derived by nature will have this issue. The unit of scale matters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Only shapes that are composed of straight line segments and can be easily measured as such do not have this problem: triangles, rectangles, hexagons, etc. Such shapes are mathematical or created by humans.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-06-19T09:23:46.220" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10621" PostTypeId="1" CreationDate="2017-06-19T11:03:39.253" Score="1" ViewCount="1445" Body="&lt;p&gt;Why does mineral halite has a cubic crystal ? Is this a result of the way by which sodium ions and chloride ions are held together ?  And what is the relation between the cubic crystal of halite and its cleavage ?&lt;/p&gt;&#xA;" OwnerUserId="6908" LastActivityDate="2017-06-20T04:24:31.447" Title="Why does halite have a cubic crystal" Tags="|minerals|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10622" PostTypeId="2" ParentId="10619" CreationDate="2017-06-19T11:23:36.900" Score="8" Body="&lt;h1&gt;Erratic Climate&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Lets take Broome, Australia as our example. Broome gets 615mm of rain a year (24 inches), including 58/182/180/102mm in Dec through March. Coupled with average highs in the low 90s, this would be fine for the sort of agriculture you see in South Texas. However, Broome's rainfall is very erratic. For example, in 2016, the rainy season started January 15th, with 23 mm of rain over three days. In 2017 (really 2016, again) the rainy season started December 4th. December 2016 also featured 222mm of rain (remember the average is only 58mm) including 113mm on Dec 23rd and 24th. 2016-2017 featured 222/230/249/114mm of rain, with significant rainfall later into April. 2015-2016 featured 0/119/26/28mm of rain. One year saw too little rainfall to grow even millet, while the next year had enough rain to support paddy rice. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Laterite&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Old tropical soils in rainy or monsoonal rainy regions tend to have their soils leached of useful nutrients. The resulting soil is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Laterite&quot; rel=&quot;noreferrer&quot;&gt;laterite&lt;/a&gt;, and it is heavily enriched in aluminum and iron ore. On the one hand, this explains the &lt;a href=&quot;https://en.wikipedia.org/wiki/Iron_ore_mining_in_Western_Australia&quot; rel=&quot;noreferrer&quot;&gt;mineral wealth&lt;/a&gt; of &lt;a href=&quot;https://en.wikipedia.org/wiki/Weipa,_Queensland#Bauxite_mining&quot; rel=&quot;noreferrer&quot;&gt;tropical Australia&lt;/a&gt;. On the other, laterite (alternately called &lt;a href=&quot;http://www.fao.org/docrep/x5867e/x5867e03.htm#1.2%20Related%20geographic%20distribution&quot; rel=&quot;noreferrer&quot;&gt;ferralsols&lt;/a&gt;, especially by the UN Food and Agriculture Organization (FAO) ) is hard to farm, with few minerals for the plants, poor moisture retention, and the tendency to form an iron-hardened crust in the dry season. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Not enough people&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;This is sort of a meta-reason, but Northern Australia is a long way from anywhere. Without very many people, it is hard to build a stable agricultural economy. If a bunch of people where sent there and forced to survive, they'd probably eke something out (for example, like the people who first populated Sydney, or South Africa). But since that never happened...population of the reason never happened. Sort of circular reasoning, but without ever having a reason for a lot of people to show up in Northern Australia (prison colony, religious persecution, etc) no one has ever made the infrastructure that successful farming operations could be based off of. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2017-06-19T11:23:36.900" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10623" PostTypeId="1" CreationDate="2017-06-19T12:27:34.653" Score="1" ViewCount="82" Body="&lt;p&gt;Could we classify oil shale as a biochemical sedimentary rock ? Oil shale is a muddy rock contains Kerogen. So I think in oil shale to be a mixture of Kerogen and mud sediments, and that's not the case, for instance, with the biochemical limestone where the solid remains of the living organisms formed the rock. So in limestone the organic material formed the rock, but in oil shale the organic material didn't, it is just, in my thoughts, preserved in the rock, or I am wrong ? enlighten me, please ! &lt;/p&gt;&#xA;" OwnerUserId="6908" LastActivityDate="2017-06-19T12:27:34.653" Title="classification of oil shale" Tags="|rocks|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10624" PostTypeId="2" ParentId="10619" CreationDate="2017-06-19T21:42:18.113" Score="5" Body="&lt;p&gt;Kingledion's answer speaks to the challenges of the soil and climate for agriculture in northern Australia. However, it seems there is nevertheless significant untapped potential.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Arable Soil&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The Australian government agency Commonwealth Scientific and Industrial Research Organisation &lt;a href=&quot;https://www.csiro.au/en/Research/Major-initiatives/Northern-Australia/Unlocking-northern-Australia&quot; rel=&quot;nofollow noreferrer&quot;&gt;has concluded&lt;/a&gt; that there is &quot;at least 16 million hectares of soil that’s suitable for intensive agriculture&quot;.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Irrigation Potential&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;CSIRO further reports (ibid.) &quot;around 15,000 GL [of water annually]—enough to irrigate almost 1.5 million hectares—could be made available for irrigation&quot; with improved infrastructure.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Political Will&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The Australian government is pursuing modest agricultural expansions. The 2015 White Paper on Developing Northern Australia announced an A$170m allocation for water development in northern Australia, including expanded funding for the Ord River Irrigation Scheme. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Developments must contend with the wishes of local stakeholders and state funding limitations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Proposals for transformative agricultural developments, including perhaps soil improvement and settlement policies, apparently lack political will. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Kimberley_Plan&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kimberley Plan&lt;/a&gt;, a WWII-era scheme to resettle Jewish refugees in northern Australia, was vetoed by the Australian government in 1944 on the grounds that it would &quot;depart from the long-established policy in regard to alien settlement in Australia&quot;. Immigration remains restricted in Australia, and the government is unlikely to import massive foreign manpower as part of a development scheme. The population and economic pressures within Australia are evidently insufficient to motivate a large-scale development of the north.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.csiro.au/en/Research/Major-initiatives/Northern-Australia/Achievements/Water-resource-assessments&quot; rel=&quot;nofollow noreferrer&quot;&gt;Further CSIRO info is available here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="8385" LastEditorUserId="8385" LastEditDate="2017-06-20T02:26:16.343" LastActivityDate="2017-06-20T02:26:16.343" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10625" PostTypeId="1" AcceptedAnswerId="10657" CreationDate="2017-06-19T22:34:52.863" Score="20" ViewCount="22647" Body="&lt;p&gt;When the ocean is still, i.e. there aren't waves that disturb the surface, you often see &quot;lanes&quot; of water that seem flat as opposed to areas where the wind causes ripples. What causes this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/H8hAe.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/H8hAe.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8389" LastActivityDate="2022-05-02T14:07:38.750" Title="Lanes of flat ocean surface in coastal waters" Tags="|ocean|water|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10626" PostTypeId="1" AcceptedAnswerId="10632" CreationDate="2017-06-19T23:29:02.077" Score="4" ViewCount="1181" Body="&lt;p&gt;For how long have deserts existed and which one would be the first to be created? I'm talking about arid, dry deserts, not the Antarctic or Arctic or any other icy deserts.&lt;/p&gt;&#xA;" OwnerDisplayName="user8390" LastEditorDisplayName="user8390" LastEditDate="2019-12-09T13:00:36.583" LastActivityDate="2019-12-13T23:31:59.123" Title="When was the first not-icy desert formed?" Tags="|desert|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="10627" PostTypeId="1" AcceptedAnswerId="10661" CreationDate="2017-06-20T00:03:12.437" Score="6" ViewCount="711" Body="&lt;p&gt;I know that smog is generally a mixture of various chemicals, such as peroxyacetyl nitrate (PAN) and ozone. I also know that smog obscures visibility.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is two-fold:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;What chemical in smog generally obscures visibility (discounting aerosols)?&lt;/li&gt;&#xA;&lt;li&gt;Is there a relationship between the concentrations of the chemical and the optical depth/visibility of the smog?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-12-14T11:05:13.723" Title="Which chemicals in smog obscure visibility?" Tags="|air-pollution|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10628" PostTypeId="1" AcceptedAnswerId="10655" CreationDate="2017-06-20T01:18:00.553" Score="3" ViewCount="1041" Body="&lt;p&gt;&lt;a href=&quot;http://www.eclipse2017.org/2017/weather/2017_clouds.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;The following page&lt;/a&gt; describes the historical cloud amount at various locations along the path of totality of Solar Eclipse 2017.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How do I interpret the cloud chart?&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;When it says the cloud amount is 50%, does it mean that half of the sky is visible?&lt;/li&gt;&#xA;&lt;li&gt;In the following chart&lt;a href=&quot;https://i.stack.imgur.com/Ec0iA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ec0iA.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;how is the mean calculated? It's clearly not the mean of other numbers in that row.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;In that chart, how should I interpret the terms &quot;clear&quot;, &quot;scattered&quot;, &quot;broken&quot;, &quot;overcast&quot;, and &quot;obscured&quot;? I understand what they mean in English, but what do they mean in terms of my ability to see the eclipse?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="8391" LastActivityDate="2017-06-21T13:05:02.000" Title="How to interpret cloud coverage chart?" Tags="|meteorology|clouds|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10629" PostTypeId="2" ParentId="10626" CreationDate="2017-06-20T01:48:20.077" Score="3" Body="&lt;p&gt;the first one would have been the entire planet soon after it formed (~4.4 billion years), the planet had to cool quite a bit before liquid water could exist. deserts basically predate all the other climes on earth. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2017-06-20T01:48:20.077" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10630" PostTypeId="2" ParentId="10617" CreationDate="2017-06-20T02:53:50.207" Score="5" Body="&lt;p&gt;This a great example of &quot;self-organization&quot; in a geomorphological system; this one an oscillating system at a fairly large scale. On a much smaller scale, you find similar structures on sand dune surfaces themselves as well as dry dusty dirt roads:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WlUYl.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WlUYl.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Self organization (and its scaling) is a complex process delicately dependent on just a few variables, in the case of desert dunes, wind carrying capacity, and critically, bed surface. (You can also find examples of oscillating chemical self organization in rocks when, for example, you see &quot;tree-rings&quot; around plagioclase crystals in anorthosites.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The hidden (and surprising) complexity of self organization in natural systems is reflected in the difficulty in modelling these behaviors. In &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/001282529090029U&quot; rel=&quot;noreferrer&quot;&gt;the case of small sand dunes&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...a complex process of ripple coalescence is responsible for this evolution of the ripple field. Small, fast-moving ripples catch up with and are absorbed by larger, slower forms, each such merger resulting in a growth of the mean wavelength and a decline in the relative dispersion of the wavelengths.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This mechanism may figure in &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0169555X05001674&quot; rel=&quot;noreferrer&quot;&gt;modelling the formation of large dune fields&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Because dunes reorient only at their crest terminations with a change in wind regime, the rate of formation of a new pattern of small dunes is typically faster than the rate of reorientation of the existing pattern, resulting in the superposition of simple patterns to give rise to complex patterns. Complex patterns are distinct from spatial changes in a simple pattern, and from the type of superposition that characterizes compound/complex dunes. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There are literally tons of examples of self organization in earth systems, at all kinds of scales, but that NASA image is a stunner!&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-06-20T02:53:50.207" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10631" PostTypeId="2" ParentId="10598" CreationDate="2017-06-20T03:47:22.763" Score="2" Body="&lt;p&gt;I am grateful to Daryl Herzmann at Iowa State, who wrangles data at the &lt;a href=&quot;https://mesonet.agron.iastate.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iowa State Environmental Mesonet&lt;/a&gt; for providing an off-exchange answer.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Synoptic reset times are between 51 and 57 minutes past the hour, depending on the site. A possible way to automate the use of ASOS data is to find the modal minute value in the data. This seems highly likely to be the reset minute.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The most quoted daily rainfall total is measured midnight to midnight,  local standard time, by summing the synoptic hourly total. Because it is standard time, DST is ignored.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;I have created &lt;a href=&quot;https://github.com/rmcd1024/daily_precipitation_totals/&quot; rel=&quot;nofollow noreferrer&quot;&gt;a github site&lt;/a&gt; that includes R code to compute daily precipitation totals from ASOS data. This code:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Uses the modal minute as the ASOS reset minute&lt;/li&gt;&#xA;&lt;li&gt;Converts the time from GMT to local&lt;/li&gt;&#xA;&lt;li&gt;Subtracts 3600 seconds if DST is in effect&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Daryl has a &lt;a href=&quot;https://mesonet.agron.iastate.edu/present/130903_isu/isumet_fall2013_web.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;presentation that discusses precipitation measurement&lt;/a&gt;. Thank you Daryl!&lt;/p&gt;&#xA;" OwnerUserId="8368" LastActivityDate="2017-06-20T03:47:22.763" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10632" PostTypeId="2" ParentId="10626" CreationDate="2017-06-20T03:53:52.620" Score="5" Body="&lt;p&gt;Deserts have existed since at least the Permian period (299-251 million years ago) when the world's continents had combined into the Pangaea supercontinent. Stretching from pole to pole, this land mass was large enough that portions of its interior received little or no precipitation, &lt;a href=&quot;https://ucmp.berkeley.edu/permian/permian.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;according the University of California Museum of Paleontology&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pangaea broke into smaller land masses which were moved across the surface by tectonic forces, a process that both changed global climate patterns and the climate those continents were exposed to. As a result, current desert regimes date back to no more than 65.5 million years, according to &lt;a href=&quot;https://www.britannica.com/science/desert&quot; rel=&quot;nofollow noreferrer&quot;&gt;this Encyclopedia Britannica article&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The desert environments of the present are, in geologic terms,&#xA;  relatively recent in origin. They represent the most extreme result of&#xA;  the progressive cooling and consequent aridification of global&#xA;  climates during the Cenozoic Era (65.5 million years ago to the&#xA;  present), which also led to the development of savannas and scrublands&#xA;  in the less arid regions near the tropical and temperate margins of&#xA;  the developing deserts. It has been suggested that many typical modern&#xA;  desert plant families, particularly those with an Asian centre of&#xA;  diversity such as the chenopod and tamarisk families, first appeared&#xA;  in the Miocene (23 to 5.3 million years ago), evolving in the salty,&#xA;  drying environment of the disappearing Tethys Sea along what is now&#xA;  the Mediterranean–Central Asian axis.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Which would put the oldest of &quot;modern&quot; desert somewhere in the region of what later became North Africa or South Asia.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastEditorUserId="7314" LastEditDate="2019-12-12T23:38:15.750" LastActivityDate="2019-12-12T23:38:15.750" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="10634" PostTypeId="2" ParentId="10621" CreationDate="2017-06-20T04:24:31.447" Score="2" Body="&lt;p&gt;Halite has a cubic structure as a result of its ionic bonds and ion sizes. This means that the positively charged sodium tends to be surrounded by as many negatively charged chlorine ions as possible (and vice versa) but that attraction is working against the repulsion of positive charges from each other and negative charges from each other. It balances nicely with cubic packing of the atoms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hVb2p.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hVb2p.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This does control the cleavage direction but there are other cubic minerals where the ion sizes and charge mean the cleavage is stronger in different directions. A good example is fluorite, calcium fluoride, which often forms cubic-shaped crystals but has octahedral cleavage.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-06-20T04:24:31.447" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10635" PostTypeId="1" CreationDate="2017-06-20T04:27:52.867" Score="2" ViewCount="42" Body="&lt;p&gt;There are a lot of papers on the web but they don't explain the concepts, they just mention them, taking for granted that the reader knows the concepts.&#xA;I mean piggyback basin, forearc, back arc, intracratonic, intramontane, etc.&lt;/p&gt;&#xA;" OwnerUserId="7538" LastEditorUserId="94" LastEditDate="2017-06-20T06:22:27.977" LastActivityDate="2017-06-20T08:30:04.190" Title="Where can I find information about the basic concepts of sedimentary basins?" Tags="|geology|structural-geology|regional-geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10638" PostTypeId="2" ParentId="10635" CreationDate="2017-06-20T06:21:05.347" Score="2" Body="&lt;p&gt;In general, a good answer to &quot;where can I learn the basic concepts of X&quot; is &quot;a textbook on X&quot;. For sedimentary concepts, you might try Nichols (2009), for instance. Academic papers are a publication vehicle for new research, so you'll seldom find much introductory material in them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For terms like &quot;intracratonic&quot; and &quot;intramontane&quot;, you might also find it useful to learn some common Greek and Latin prefixes and suffixes. If you look for &quot;intra&quot; in a list like &lt;a href=&quot;http://users.uoa.gr/~nektar/history/language/greek_latin_derivatives.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one&lt;/a&gt;, you'll find that it's Latin for &quot;within&quot;, and you might be able to guess that &quot;intracratonic&quot; refers to something occurring within a craton.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you just want to look up terms as you go, and you're happy with brief definitions, a specialist dictionary might also be helpful. For Earth Sciences, Allaby (2008) is a good concise dictionary, though it might be a little &lt;em&gt;too&lt;/em&gt; concise if you're a beginner.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Allaby, M. ed., 2008. &lt;em&gt;A Dictionary of Earth Sciences&lt;/em&gt; 3rd ed., Oxford: Oxford University Press.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nichols, G., 2009. &lt;em&gt;Sedimentology and Stratigraphy&lt;/em&gt; 2nd ed., Chichester: Wiley-Blackwell.&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2017-06-20T08:30:04.190" LastActivityDate="2017-06-20T08:30:04.190" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10639" PostTypeId="2" ParentId="10611" CreationDate="2017-06-20T07:54:04.203" Score="3" Body="&lt;p&gt;The drag coefficient varies with Reynolds number and hence with wind speed. Most fluid-dynamics textbooks have a graph of the drag coefficient of a sphere versus Reynolds number. Hopefully that could help. (A sphere such as a ping-pong ball is the best shape since its shape is the same in all orientations --- only a sphere has complete omnidirectional symmetry.) Because wind is rarely steady but usually includes gusts and lulls, it may be necessary to account for overshooting. A sudden gust can cause the ping-pong ball to temporarily overshoot to a higher angle than in a steady wind at the same speed as the gust.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-06-20T07:54:04.203" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10640" PostTypeId="2" ParentId="10553" CreationDate="2017-06-20T08:01:28.223" Score="1" Body="&lt;p&gt;Typhoons in the western North Pacific ocean can be larger than hurricanes, because the great expanse of ocean water in the Pacific gives them more time and space to develop. Typhoon Tip in 1979 produced gale winds or higher over a diameter of 1400 miles. This is to my knowledge the largest western Pacific typhoon of record (it was also one of the most intense --- near-all-time-record maximum sustained winds of 190 mph, minimum barometric pressure an all-time record low of 25.6 inches of mercury). Typhoon Tip's 1400-mile diameter of gale-force or higher winds is almost double that of the largest hurricanes of record.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-06-20T08:01:28.223" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10641" PostTypeId="1" CreationDate="2017-06-20T08:05:55.170" Score="3" ViewCount="43" Body="&lt;p&gt;I am trying to figure out why Lake Turkana has yielded so many hominin fossils compared to other locations in the East African Rift Valley. One of the reasons is possibly the laying of sedimentary strata and volcanic activity which creates new layers; this geologically dynamic area is therefore able to preserve fossils. But surely Lake Turkana isn't the only such area, there are other East African rift Lakes such as Tanganyika. What other factors have played into shaping this remarkable fossil rich area?&lt;/p&gt;&#xA;" OwnerUserId="8219" LastEditorUserId="8219" LastEditDate="2017-06-20T08:11:55.480" LastActivityDate="2017-06-20T08:11:55.480" Title="What factors make Lake Turkana a great location for preserving fossils?" Tags="|paleoclimatology|geomorphology|paleogeography|archaeology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10642" PostTypeId="1" CreationDate="2017-06-20T08:10:39.210" Score="1" ViewCount="108" Body="&lt;p&gt;And also, can this push continents and land-masses upward as well?I have not been informed of the phenomenon of tectonic plates rising up.&#xA;I am yet unable to find a satisfactory answer on the internet, be it in scholarly search engines or just Google.&lt;/p&gt;&#xA;" OwnerUserId="8395" LastActivityDate="2017-06-20T08:10:39.210" Title="How do tectonic plates move upward?" Tags="|plate-tectonics|tectonics|continent|" AnswerCount="0" CommentCount="2" ClosedDate="2017-06-20T11:02:20.307" ContentLicense="CC BY-SA 3.0" />
  <row Id="10643" PostTypeId="1" CreationDate="2017-06-20T10:27:17.480" Score="2" ViewCount="874" Body="&lt;p&gt;If fully penetrating stream means, the stream penetrates fully to the depth of aquifer, then doesn't it mean that there is zero conductance or leakance? The leakance or conductance is a term used to accommodate no low conductivity sediments at the bottom of stream which usually serve as interface between stream and aquifer.  Can somebody show with sketches, what is difference between the two types also including leakance or conductance term. &lt;/p&gt;&#xA;" OwnerUserId="5557" LastActivityDate="2017-09-03T10:34:54.183" Title="What is difference between partially penetrating stream and fully penetrating stream?" Tags="|hydrology|hydrogeology|water-table|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10644" PostTypeId="1" AcceptedAnswerId="10725" CreationDate="2017-06-20T10:39:58.917" Score="5" ViewCount="1804" Body="&lt;p&gt;I was reading a book about tectonic plate boundaries, and I came across this paragraph:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/aSypf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aSypf.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It says that when a plate edge slides with another plate edge it causes a vertical fault, as San Andreas fault. I thought that SAF is a horizontal fault i.e. strike-slip fault. So what does the book mean by vertical faults?&lt;/p&gt;&#xA;" OwnerUserId="6908" LastEditorUserId="2536" LastEditDate="2017-07-01T05:49:54.327" LastActivityDate="2017-07-01T05:49:54.327" Title="Is San Andreas fault horizontal or vertical?" Tags="|transform-fault|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10645" PostTypeId="2" ParentId="1062" CreationDate="2017-06-20T13:34:03.427" Score="3" Body="&lt;p&gt;I find the following method very straightforward and elegant. So maybe I can convince you to consider it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the South American (SA) monsoon, &lt;a href=&quot;https://icess.eri.ucsb.edu/gem/papers/silva.2007.atmos.sci.letters.lisam.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Silva et al. (2007)&lt;/a&gt; and &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/JCLI-D-11-00335.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Carvalho et al. (2012)&lt;/a&gt; proposed the Long-scale South American Monsoon Index (LISAM), based on the annual cycle of some fields.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the 2012 paper, where several precipitation datasets are used to calculate what you want, the methodology is as follows:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Compute the empirical orthogonal function (EOF) of a precipitation gridded data on land over SA. (There are some details as weigth by latitude, you may want to do combined EOF etc etc... but the essence of the idea is the same). Note that EOF is computed on raw precipitation, not anomalies.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The first EOF represents the annual (seasonal) cycle of the monsoon. The First PC (PC1) shows it clearly (Figure 2 in Silva et al. 2007)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;At last, having the time series of PC1, you can determine:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Start (onset): the day in which PC1 turns positive.&#xA;End (demise): the day in which PC1 turns negative.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further detailes are given in the cited papers. Hope it helps.&lt;/p&gt;&#xA;" OwnerUserId="8396" LastActivityDate="2017-06-20T13:34:03.427" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10646" PostTypeId="2" ParentId="10627" CreationDate="2017-06-20T16:18:11.627" Score="8" Body="&lt;h1&gt;Winter and Summer smog&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;There are two types of smog: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;winter smog:&lt;/strong&gt; &#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;high emissions of soot and of $SO_2$ through heating with wood, coal, etc.&lt;/li&gt;&#xA;&lt;li&gt;$SO_2$ reacts to sulfuric acid =&gt; formation of particulate matter =&gt; reduced visibility&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;summer smog (photochemical smog):&lt;/strong&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;strong sunlight and emissions of $NO_X$, $CO$ and VOCs&lt;/li&gt;&#xA;&lt;li&gt;emissions of primary particulate matter not necessary&lt;/li&gt;&#xA;&lt;li&gt;reaction of these air pollutants to other gaseous air pollutants (PAN, $O_3$, $HNO_3$) through photo-oxidation&lt;/li&gt;&#xA;&lt;li&gt;photo-oxidation of various VOCs =&gt; lump together to ultra-fine particles (secondary PM) =&gt; particles grow &lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h1&gt;Species that impact visibility&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;We 'need' the gaseous air pollutants to form secondary aerosol particles. The reduced visibility during winter and summer smog events is caused by these secondary aerosol particles (they scatter the light and, by this process, reduce visibility). The gaseous air pollutants might contribute to reduced visibility but their contribution is negligible compared to the aerosol impact. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Contribution of different aerosol species&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The composition as well as the size distribution of the aerosol particles is important to determine the aerosol's optical properties. If you look into mass concentrations, a given mass of fine particles extincts more light than the same mass of coarse particles. If you look into composition (inorganic components), nitrate extincts more light than sea salt and sulfate. The extinction of organic aerosol depends on their composition (I have no idea which factors/species are relevant there).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are interested in further literature on the impact of the particle composition on the light extinction you might look into &lt;a href=&quot;http://www.tandfonline.com/doi/abs/10.3155/1047-3289.57.11.1326&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pitchford et al. (2007)&lt;/a&gt;. I didn't find a publication which quantifies the contribution of different particulate compositions/species to light extinction for smog. However, &lt;a href=&quot;http://www.tandfonline.com/doi/abs/10.3155/1047-3289.57.11.1326&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pitchford et al. (2007)&lt;/a&gt; deals with light extinction for calculating the optical thickness from model data.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastEditorUserId="5594" LastEditDate="2017-06-21T10:12:41.067" LastActivityDate="2017-06-21T10:12:41.067" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10649" PostTypeId="1" CreationDate="2017-06-20T19:52:56.160" Score="5" ViewCount="86" Body="&lt;p&gt;The Earth's magnetic field makes continuous battle with external disturbances to protect Earth from unwanted ramifications. Asteroids passing by, solar flares, and other ET disturbances may cause magnetic field anomaly which may affect atmospheric circulation and convection which may cause wind and water storms such as tsunamis, tornadoes etc. It can also affect air transport by disrupting the normal functioning of engines and/or creating drag-force that either drags aeroplanes and ships down or forward, in general, causing unintended motion. Are there studies about,&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;the effect of ET perturbations on Earth's magnetic field. &lt;/li&gt;&#xA;&lt;li&gt;are there historical evidences for the effects of such disturbances on Earth's weather and climate (e.g., the relationship between earth's magnetic field, B ~ convection, atmospheric circulation)&lt;/li&gt;&#xA;&lt;li&gt;how much drag force can be generated from a minute disturbance from solar wind? &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="4877" LastEditorUserId="6031" LastEditDate="2019-01-13T01:00:18.210" LastActivityDate="2019-01-13T01:00:18.210" Title="Does solar wind perturb Earth's magnetic field ? If so, what are the consequences?" Tags="|geomagnetism|severe-weather|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="10650" PostTypeId="2" ParentId="8298" CreationDate="2017-06-20T21:10:31.347" Score="1" Body="&lt;p&gt;The hill to the south in your map is called Palm Hill, probably because of its somewhat resemblance to a palm frond. It is an erosion-resistant hill or knoll that protrudes above the surrounding alluvial plain. As @KnobScratcher points out, the feature is the result of erosion in that it created the alluvial plain that surrounds the knoll. Erosion also sculpted the small gullies that make the structure resemble a palm frond. Without the alluvial plain to fill in the valleys surrounding the knoll, and thus make the hilltop stand out, I doubt it would be very noteworthy.&lt;br&gt;&lt;br&gt;Most likely the structure to the north is of the same origin.&lt;br&gt;&lt;br&gt;There is a Larkspur, CA planning document that gives blurb about &lt;a href=&quot;http://www.ci.larkspur.ca.us/DocumentCenter/Home/View/96&quot; rel=&quot;nofollow noreferrer&quot;&gt;Palm Hill&lt;/a&gt;. It is on page seven of this document.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2017-06-20T21:10:31.347" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10652" PostTypeId="1" CreationDate="2017-06-21T02:50:30.717" Score="6" ViewCount="412" Body="&lt;p&gt;How do scientists use data at the crater site to estimate when a meteorite or asteroid impacted the earth?&lt;/p&gt;&#xA;" OwnerUserId="8400" LastActivityDate="2017-06-23T07:32:56.333" Title="What techniques are used to date asteroid impacts?" Tags="|impacts|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10655" PostTypeId="2" ParentId="10628" CreationDate="2017-06-21T13:05:02.000" Score="2" Body="&lt;p&gt;The mean is probably the average cloud cover in percentages: 41% cloud coverage on average over time. The categories you mentioned: 'clear', 'scattered', 'broken' and 'overcast' are defined in different ways sometimes. Basically there is a human observing the sky analyzing the coverage in oktas or tenths (e.g. 6/8), or more likely there is a sounding device looking through the sky and getting a value in percentages of the cloud cover (e.g. 75.0%). To get one of these categories from the device data, the percentages are turned into oktas or tenths. Some data is lost in this transformation and thus from the categorized data it is impossible to get calculate the actual mean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some use more the oktas (World Meteorological Organization) and others (I would guess often USA) tenths in the categorization. Also after quick googling the categorization bins seem to be differ from source to source at least for the ones who use tenths. The clear and overcast bins are for all the same less than 1/8 or 1/10 and more than 7/8 or 9/10 respectively. Obscured also always means basically that the value is undetermined: perhaps there is fog and the device doesn't get the responses it would've wanted. Some have also a category 'few', but since it was not present in the data they have used a categorization that doesn't include it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Based on all above I would guess the categorization is the same as in this &lt;a href=&quot;http://www.meteor.wisc.edu/~hopkins/aos100/sfc-anl.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;webpage&lt;/a&gt;. Categories are clear: less than 1/10, scattered: 1/10 to 5/10, broken: 6/10 to 9/10 and overcast: over 9/10. As the tabulated values are historical they give a climatological average of what are the possibilities of different cloud cover scenarios. I would suspect that clear and scattered scenarios are good enough for watching an eclipse so e.g. in Salem you would have a 32.2 + 19 = 51.2 percent chance to have a decent or better viewing conditions.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastActivityDate="2017-06-21T13:05:02.000" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10657" PostTypeId="2" ParentId="10625" CreationDate="2017-06-21T18:31:12.073" Score="9" Body="&lt;p&gt;There can be many reasons for the lines that you see where the water is not rippled.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) There is no wind on those specific areas.  Not likely in the photo used as the example but especially when there are cold fronts involved the wind can be very inconsistent over short horizontal distances.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) You may be seeing the influence of boat wakes that passed over the area recently.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) You may be seeing variation of the underlying ocean currents.  Especially near the coast with tide changes there can be zones of significant ocean current.  Wind and ocean currents have an influence on wave height and shape.  When the wind blows against the current you get higher steeper waves.  When you get wind blowing with the current you get shorter shallower waves (the smooth sections).  The currents are not just horizontal but have vertical components as well.  The lines identified could be vertical eddies in the current smoothing the surface whereas the smooth / rough line in the foreground is were the major ocean flow is going in opposite directions to each other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;4) If the coast in the foreground is shallow and there are waves coming to shore there then the lines identified to be rip currents caused by water returning from the coast line.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From my personal experience I would say that you are seeing variations in the surface ocean currents, and these currents change how the wind develops waves on the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Wind_wave&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Wind_wave&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastEditorUserId="6703" LastEditDate="2017-06-22T18:18:38.970" LastActivityDate="2017-06-22T18:18:38.970" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10659" PostTypeId="2" ParentId="10581" CreationDate="2017-06-22T00:54:01.687" Score="4" Body="&lt;p&gt;Figured out my error: I was assuming that I needed to alter the filename endings / type in order to save as a genuine .grb or .grib2 file. The files are already in grib2 format despite the ending in .f000 so you should be able to leave them as that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My other error was not double checking the exact filename and path when dealing with multiple grib files across the GFS datasets. Some have slight differences in the naming convention, and when loading on pygrib it will throw the same generic &quot;import error&quot; as if the file couldn't be read.&lt;/p&gt;&#xA;" OwnerUserId="8348" LastActivityDate="2017-06-22T00:54:01.687" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10660" PostTypeId="2" ParentId="10476" CreationDate="2017-06-22T03:28:18.633" Score="2" Body="&lt;p&gt;LPG ( liquid petroleum gas) is primarily produced with &quot;natural&quot; gas. It is separated from the methane by condensation ( in &quot;gas plants&quot; ) because it is more valuable . It does not require  pipelines for distribution ; ignoring the fairly recent development of LNG ( methane) facilities. &#xA;&quot;Earth&quot; gas seems a strange term; There are wells that produce primarily CO2, There are wells that produce 75% H2S - Pincher Creek Canada ,( I believe Shell has a field in LA that produced more than 75%.). And do the sub-sea hydrates count ? Some references say they hold more methane than all traditional sources. The CO2 is used to help flush oil and gas from traditional wells so thereby could ultimately generate electricity.&#xA;My point is that TV &quot;mockumentories&quot; are not a good source for comprehensive facts.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2017-06-22T03:28:18.633" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10661" PostTypeId="2" ParentId="10627" CreationDate="2017-06-22T07:07:55.417" Score="4" Body="&lt;h3&gt;1. Basic concepts of visibility loss&lt;/h3&gt;&#xA;&lt;p&gt;The deterioration of visibility can be divided into four parts as follows:&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;em&gt;absorption of gases&lt;/em&gt; + &lt;em&gt;scattering of gases&lt;/em&gt; + &lt;em&gt;absorption of aerosol&lt;/em&gt; + &lt;em&gt;scattering of aerosol&lt;/em&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;quote from a Ph.D dissertation &lt;a href=&quot;https://helda.helsinki.fi/handle/10138/144091&quot; rel=&quot;nofollow noreferrer&quot;&gt;link here&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;scattering is a process where the incident radiation is reradiated into all directions after interacting with a scattering point&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;In the visible zone (400 nm - 700 nm), the cloud free atmosphere is remarkably transparent, This means that the absorption of the radiation at visible band occurs primarily at the surface and not within the atmosphere itself&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;We can derive that the aerosol is the dominant reason of the visibility loss.&lt;/p&gt;&#xA;&lt;p&gt;PS: the gases species can also impact the radiative transfer process of the earth system, but mainly in non-visible regions.&lt;/p&gt;&#xA;&lt;h3&gt;2. The calculation of visibility loss&lt;/h3&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://thesis.library.caltech.edu/4452/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Koschmiederp&lt;/a&gt; came up with an equation which connect the visibility and extinction coefficient &lt;span class=&quot;math-container&quot;&gt;$b_{ext}$&lt;/span&gt; as follows:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$V_R = 3.91/b_{ext} $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$V_R$&lt;/span&gt; is the visibility reduction, unit in meters;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$b_{ext}$&lt;/span&gt; is the total extinction coffecient in all aspects (containing the four subset which I have already noted).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;In the visible band, the scattering of gases can be omitted and the absorption of gases is mainly attributed to &lt;span class=&quot;math-container&quot;&gt;$NO_2$&lt;/span&gt;. As an empirical equation, the &lt;span class=&quot;math-container&quot;&gt;$b_{ext}$&lt;/span&gt; can be derived as follows:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$b_{ext} =  3f(RH)*[(NH_4)_2SO_4] + 3f(RH)*[(NH_4)_2SO_4] + 4f(RH)*[Organics] + 10[EC]+[Soil] +[0.6][Coarse\ mass]+ 3.3*[NO_2]+ 10 $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$f(RH)$&lt;/span&gt; is the function of relative humidity, it will increase with atmospheric RH.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;[Coarse mass] = [&lt;span class=&quot;math-container&quot;&gt;$PM_{10}$&lt;/span&gt;] - [&lt;span class=&quot;math-container&quot;&gt;$PM_{2.5}$&lt;/span&gt;]&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;10: the extinction of clean air&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;In this way, the visibility loss can be rebuilt.  We can derive that the &amp;quot;there is a relationship between the concentrations of the chemical and the optical depth/visibility&amp;quot; as your second question.&lt;/p&gt;&#xA;&lt;h3&gt;3. Mass concentration and visibility&lt;/h3&gt;&#xA;&lt;p&gt;A figure I clipped from &lt;a href=&quot;https://www.researchgate.net/publication/307921106_Chemical_Composition_of_PM25_and_its_Impact_on_Visibility_in_Guangzhou_Southern_China&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chen et al., 2016&lt;/a&gt; represent the relationship between &lt;span class=&quot;math-container&quot;&gt;$PM_{2.5}$&lt;/span&gt; concentration and visibility. We can see the visibility is decrease when &lt;span class=&quot;math-container&quot;&gt;$PM_{2.5}$&lt;/span&gt; increasing and the decreasing curve is sharp when the concentration is below 50 &lt;span class=&quot;math-container&quot;&gt;${u}g/m^3$&lt;/span&gt;. Besides, relative humility is a key factor here which high RH can worsen the deterioration of visibility. This is due to the hygroscopic behavior of some species (eg. &lt;span class=&quot;math-container&quot;&gt;$(NH_4)_2SO_4$&lt;/span&gt;)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/uc9Dt.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uc9Dt.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-06-22T09:03:02.483" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10662" PostTypeId="2" ParentId="10476" CreationDate="2017-06-22T08:20:17.193" Score="2" Body="&lt;p&gt;To add on to Fred above - There is something called &lt;a href=&quot;https://en.wikipedia.org/wiki/Underground_coal_gasification&quot; rel=&quot;nofollow noreferrer&quot;&gt;'Underground coal gasification'&lt;/a&gt;  where you basically react coal with steam and oxygen underground to produce a stream of carbon monoxide and hydrogen (plus minor methane). This can then be burnt as fuel or used in Fischer-Tropp manufacture of hydrocarbons.&lt;/p&gt;&#xA;" OwnerUserId="8217" LastActivityDate="2017-06-22T08:20:17.193" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10664" PostTypeId="1" AcceptedAnswerId="10665" CreationDate="2017-06-22T17:41:37.940" Score="3" ViewCount="309" Body="&lt;p&gt;I am a student programmer, with very little knowledge of geography and am working with maps for a project, and have to convert latitudes and longitudes to points on a screen (map to pixels).&lt;br&gt;&#xA;So my principal problem with the system of latitudes and longitudes is having to specify a hemisphere along with the co-ordinates of a point on a map.&#xA;  Is there a system which provides co-ordinates without having to specify a direction, which is also widely used?  And if so, do tools to convert between the two systems exist?&lt;br&gt;&#xA;For example something like the left-top corner of a map is given (0,0), and as we go right X increases, and as we go down Y increases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;" OwnerUserId="8414" LastActivityDate="2017-06-23T17:14:09.887" Title="Is there a better system than latitudes and longitudes?" Tags="|geography|cartography|" AnswerCount="3" CommentCount="4" ClosedDate="2017-06-24T13:13:42.767" ContentLicense="CC BY-SA 3.0" />
  <row Id="10665" PostTypeId="2" ParentId="10664" CreationDate="2017-06-22T18:12:14.697" Score="7" Body="&lt;p&gt;To answer the question in the title (with another question): better for what?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer the questions in the body: there is another system called rectilinear or &lt;a href=&quot;https://en.wikipedia.org/wiki/Geographic_coordinate_system#Cartesian_coordinates&quot; rel=&quot;noreferrer&quot;&gt;x-y-z Cartesian coordinates&lt;/a&gt;. This system is the same as the 3-d Cartesian coordinates you used in calculus class. The center of the Earth is (0,0,0), and generally the z-direction goes to the poles, while x and y go to the equators at right angles, and towards points specified by whatever datum you are using. For example, the North Pole could be coordinates (0,0,6353000) in meters. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for tools to do the conversion, you should probably send those kinds of questions to the &lt;a href=&quot;https://gis.stackexchange.com/&quot;&gt;GIS Stack Exchange&lt;/a&gt;. However, since they tend to be snippy when I've asked questions in the past I will tell you how I do it. I use the &lt;a href=&quot;https://jswhit.github.io/pyproj/&quot; rel=&quot;noreferrer&quot;&gt;pyproj&lt;/a&gt; package for python, which is a python wrapper around the C &lt;a href=&quot;https://github.com/OSGeo/proj.4/wiki&quot; rel=&quot;noreferrer&quot;&gt;Proj4 package&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pyproj is pretty straight forward to use, but the transformations you want might not be so easy to figure out. The information you want is the &lt;a href=&quot;http://www.epsg.org/&quot; rel=&quot;noreferrer&quot;&gt;EPSG&lt;/a&gt; numbers of the &lt;a href=&quot;http://spatialreference.org/ref/epsg/&quot; rel=&quot;noreferrer&quot;&gt;transforms&lt;/a&gt;. If you are using the common WGS-84 datum, for example, the rectilinear is 'epsg:4978' while the lat-lon is 'epsg:4326'. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A code example follows from a python (3.5) interactive console. To transform the estimated coordinates of the north pole above, we want to go from rectilinear to lat-lon.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;&amp;gt;&amp;gt;&amp;gt; import pyproj&#xA;&amp;gt;&amp;gt;&amp;gt; rectProj = pyproj.Proj(init='epsg:4978')&#xA;&amp;gt;&amp;gt;&amp;gt; latlonProj = pyproj.Proj(init='epsg:4326')&#xA;&amp;gt;&amp;gt;&amp;gt; pyproj.transform(rectProj, latlonProj, 0, 0, 6353000)&#xA;(0.0, 90.0, -3752.3142451792955)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;What we see here is that when we transform from rectilinear to lat-lon, we get a longitude of 0, latitude of 90, and azimuth (or altitude) of -3752.3 meters. So at the North Pole, 4 km below the surface. This altitude difference is due to both the roughness of my estimate and the specifics of the WGS-84 datum. To go the other way from the lat-lon Greenwich Observatory (at 51.478 degrees north, 0 degrees west; azimuth or elevation of 0 meters) we can do:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;&amp;gt;&amp;gt;&amp;gt; pyproj.transform(latlonProj, rectProj, 0, 51.478, 0)&#xA;(3980563.802812242, 0.0, 4966838.380583356)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;We see that 90 degrees north at altitude of zero in WGS-84 corresponds to that (x, y, z) triplet, in meters. Since Greenwich lies on the 'y' coordinate axis in the WGS-84 system, the y coord is zero. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this helps.&lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2017-06-22T18:12:14.697" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10666" PostTypeId="2" ParentId="10095" CreationDate="2017-06-22T19:56:41.837" Score="3" Body="&lt;p&gt;Your question is a bit confusing, but there is a strong connection between temperature and wind,in their spatial gradiant I would say, however, instead of temporal differences.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Imagine winds are only driven by changes in pressure (higher temperatures -&gt; lower pressure and vice versa). Imagine there are two surface areas with different temperatures (say some frozen lake and a nice grass field in the sun nearby). Therefore the horizontal pressure gradient (due to horizontal temperature gradient) would force the existence of wind, blowing from the High to the Low pressure zones. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now imagine another situation where there is no horizontal gradient (differences) of temperature nor pressure. The surface is homogeneous. Now imagine all the homogenous surface gets warmer at the same rate, but still remains homogeneous). There would be no reason, thus, for stronger winds (apart from molecular-scale phenomena due to warming, but I believe is not the focus here).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To summarize: winds driven by temperature differences do get stronger if temperature differences spatially increase. A high temperature, alone, does not say much and is way to vague to relate to what you ask.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could also think of Antartica: very cold and high speed winds. Just to give a hint of how more complicated the relation between temperature and wind may be.&lt;/p&gt;&#xA;" OwnerUserId="8396" LastEditorUserId="8396" LastEditDate="2017-06-30T20:03:10.973" LastActivityDate="2017-06-30T20:03:10.973" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10667" PostTypeId="2" ParentId="9634" CreationDate="2017-06-22T20:09:28.207" Score="5" Body="&lt;p&gt;I imagine you have a horizontal grid (x,y) and wind components u(x,y) and v(x,y).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Normally we do 1-degree of latitude constant (y-dimension) and equal to 110000 m. So your &lt;code&gt;dy&lt;/code&gt; depends on how many degrees per grid point you have (yresolution). However, &lt;code&gt;dx&lt;/code&gt; will vary according to the latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;code&gt;dy=110000*yesolution;&lt;/code&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, we may use &lt;strong&gt;centered finite differences&lt;/strong&gt; to compute what you want. (Below is a Matlab code, but I believe generic enough to be reproducible in other languages).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;code&gt;for y=2:length(lat)-1&#xA;     dx=abs(110000*cos(latx(y)*(2*pi/360))*xresolution);&#xA;     for x=2:length(lon)-1&#xA;          div(x,y,1)= (u(x+1,y,1)-u(x-1,y,1))/(2*dx) + (v(x,y+1,1)-v(x,y-1,1)/(2*dy);&#xA;     end&#xA; end&lt;/code&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that you will have an empty frame around your divergence field when x=1, x=max(x), y=1 and y=max(y), once they do not have two neighboors to compute the differences. The same is observed when you do this with &lt;code&gt;hdivg&lt;/code&gt; function in Grads, for example. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;By the way, this is based on and yields the same result as Grads (I have checked!) using &lt;a href=&quot;http://cola.gmu.edu/grads/gadoc/gradfunccdiff.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;cdiff&lt;/a&gt; to reproduce &lt;code&gt;hdivg&lt;/code&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also note that the cosine function here works with radians, so if you compute cosines in degrees directly (i.e. &lt;code&gt;cosd&lt;/code&gt; function in Matlab), you should omit the term scaling by &lt;code&gt;(2*pi/360)&lt;/code&gt;, which is just a conversion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope it helps!&lt;/p&gt;&#xA;" OwnerUserId="8396" LastEditorUserId="8396" LastEditDate="2017-07-02T22:42:39.697" LastActivityDate="2017-07-02T22:42:39.697" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10668" PostTypeId="2" ParentId="8656" CreationDate="2017-06-22T20:15:55.557" Score="1" Body="&lt;p&gt;I strongly recoment using &lt;a href=&quot;https://www.mathworks.com/help/matlab/ref/interp2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;interp2 funtion&lt;/a&gt; from Matlab or any other equivalent in other languages. I have used it to do similar tasks.&lt;/p&gt;&#xA;" OwnerUserId="8396" LastActivityDate="2017-06-22T20:15:55.557" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10669" PostTypeId="2" ParentId="10652" CreationDate="2017-06-23T07:32:56.333" Score="4" Body="&lt;p&gt;Several possible ways..&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Stratigraphic (Local):&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;If the crater has been buried, just date the first rocks that are on top of the crater but not disturbed by it; this can be done using fossil-based dating if no good radiometric techniques are available.  This has the advantage of being unambiguous, but the problem could be, especially for land based craters, that there is a gap between crater formation and new sediment deposition.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Stratigraphic (Regional)&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;If you can find a layer of ejecta (famously the layer of Iridium-rich ejecta from the K-T impact) and relate it to your crater, then you can often date this very precisely, more so than the disturbed area around the crater itself.  This has the potential to be more accurate than any other method, but you have to be sure that the Iridium-rich layer you are dating actually corresponds to the crater.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Radiometric&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;A large impact will almost certainly melt some rock locally at the site of impact, resetting any radiometric 'clocks' in that rock. If you can locate this impact melt, then there are a variety of radiometric techniques that you can apply to it, depending on the mineralogy. Potassium-Argon would be an example.&lt;/p&gt;&#xA;" OwnerUserId="8217" LastActivityDate="2017-06-23T07:32:56.333" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10670" PostTypeId="1" CreationDate="2017-06-23T11:23:29.557" Score="4" ViewCount="502" Body="&lt;p&gt;I used the corner filter (band pass) with this frequency values (8,10,45,50). I get ringing effect on the data. my questions are:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;what is the name of this effect and the cause?&lt;/li&gt;&#xA;&lt;li&gt;should be removed and how?&#xA;3.on what basis the frequency values should be chosen?&lt;/li&gt;&#xA;&lt;li&gt;what are the visual features of seismic data make us decided the processing steps.   &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;After filter:&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FqcRu.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FqcRu.png&quot; alt=&quot;data after filter &quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Before filter:&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/O5MVe.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/O5MVe.png&quot; alt=&quot;data before filter &quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="5551" LastEditorUserId="2536" LastEditDate="2017-07-06T10:45:40.597" LastActivityDate="2017-07-06T10:45:40.597" Title="What causes ringing effect when using corner filter?" Tags="|geophysics|seismology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10671" PostTypeId="2" ParentId="10476" CreationDate="2017-06-23T15:15:17.887" Score="1" Body="&lt;p&gt;If you watch older British ( and some American )films you will see large gas accumulators ; typically 50 M in diameter and in height with external steel framework which permitted them to rise and fall depending on storage volume. This was called &quot;water gas&quot; which sounded better than coal gas.&#xA;There are some &quot;fire flood &quot; fields to produce regular oil and gas ,And kerogen ; air is blown down some wells to burn oil/gas in situ and oil and gas are produced at other wells. Usually the air is alternated with water to also get a water flood.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2017-06-23T15:15:17.887" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10672" PostTypeId="2" ParentId="10664" CreationDate="2017-06-23T16:39:54.390" Score="3" Body="&lt;p&gt;Better is first and foremost opinion based so cannot be answered with a conical answer, but, will give it a stab anyway.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, it is entirely dependent on application.  Start with your suggestion of a 0,0 based coordinate system.  This is used for many maps.  It also has very little to associate it with reality as it is a two dimensional representation for a three dimensional problem.  It works, somewhat, but for closer to reality the smaller of area that is being represented.  It is &quot;better&quot; potential for reasonable speed surface travel and location applications like driving and walking.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lat/Long is a navigational representation in three dimensions of a three dimensional situation.  It becomes a far better solution for navigation when the curvature of the Earth and movement of the Earth becomes an issue.  Long range ballistics, air travel, ocean navigation, etc.  These all do not work with a flat 2D representation of a 3D reality, they need spherical coordinates, and that is were lat/long came in.  Spheres are generally measured in angles, not lengths.  There are other factors in navigation such as the rotation of the Earth, but Lat/Long was the attempt to have a better system for those applications, and it is better.  It is not actually what most would consider the best, but it has been around, known and used for a long time so is typically understood well by those who need it.  It has drawbacks, like units (degrees, minutes and seconds) are not uniform size.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A truer representation would be a spherical coordinate system, but would this actually be better?  It is a true representation in 3D of location, but one that for most people has little to no meaning.  Who, for most applications, needs to know their position at any time as described by distance from and angle to the center of the Earth.  It is a much better and needed method if say you are building a cyclotron that accelerated particles to a high percentage of the speed of light, but not for applications that most of us will ever consider.&lt;/p&gt;&#xA;" OwnerUserId="6178" LastActivityDate="2017-06-23T16:39:54.390" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10673" PostTypeId="2" ParentId="10664" CreationDate="2017-06-23T17:14:09.887" Score="3" Body="&lt;p&gt;The other answers are correct on the subjectivity of &quot;better.&quot; They are also right, in that the answer you may get will depend on your application.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My answer is yes and no.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes: There is a way to convert from latitude-longitude coordinates, but it depends on the projections. Python has become my favorite tool for programming and creating plots, especially maps. Specifically the Basemap module. See some &lt;a href=&quot;https://matplotlib.org/basemap/users/examples.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;examples&lt;/a&gt;. Careful reading of the examples show that it can transform latitude and longitude coordinates into X,Y coordinates (in meters): &lt;code&gt;x, y = m(lons, lats)&lt;/code&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;No: The flaw with such a system is that the Earth is not flat; it is round. Say your point (0,0) is your left-top corner and (R,0) is your right-top corner. They are the same exact (or nearly exact) point, but on a map, they are a distance R away. This is why Greenland and Antarctica look so large on the Mercator projection.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-06-23T17:14:09.887" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10674" PostTypeId="2" ParentId="10095" CreationDate="2017-06-23T22:33:37.200" Score="3" Body="&lt;p&gt;Neither. Winds speed increases at a given location due to four different things:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The influence of friction decreases&lt;/li&gt;&#xA;&lt;li&gt;Areas of higher wind speed are transported in (yes, the wind blows the wind- that is why it is such a difficult problem)&lt;/li&gt;&#xA;&lt;li&gt;The difference in pressure over a distance increases.&lt;/li&gt;&#xA;&lt;li&gt;Air is trapped to moving along a curve, and the curvature increases (like a spinning ballerina)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Your question filters out two possibilities.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Since temperature decreases with height, and the influence of friction decreases with height, then winds will &lt;em&gt;generally&lt;/em&gt; be faster where it is colder, but only in a very general sense. This does not mean that the temperature makes wind faster. Correlation does not imply causation.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Differences in pressure over a distance, particularly horizontal distances, may increase the wind. Since pressure is &lt;em&gt;generally and approximately&lt;/em&gt; proportional to temperature, then differences in temperature will increase wind speeds.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;What is the most important factor? That really depends on where you are. When discussing atmospheric dynamics (which covers wind and forces), without making assumptions, you will rarely get a definitive answer.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-06-23T22:33:37.200" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10678" PostTypeId="1" CreationDate="2017-06-24T15:05:30.380" Score="6" ViewCount="142" Body="&lt;p&gt;Seeing all these rock identification questions, got me wondering, is there no straightforward guided rock identification website?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Intro to Geology lab, I remember going through a bit of a process towards trying to identify different rocks.  There are some pretty decent cloud sites/charts around these days, not just basic descriptions like &lt;a href=&quot;http://www.srh.noaa.gov/jetstream/clouds/cloudwise/types.html&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;, &lt;a href=&quot;http://www.nws.noaa.gov/om/brochures/cloudchart.pdf&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;, and &lt;a href=&quot;https://www.ec.gc.ca/meteoaloeil-skywatchers/default.asp?lang=En&amp;amp;n=5A0D647D-1&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;, but great in-depth site like &lt;a href=&quot;http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/cld/cldtyp/home.rxml&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;, and and especially these step-by step guides like &lt;a href=&quot;https://www.wmocloudatlas.org/cloud-identification-guide.html&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;http://wvscience.org/clouds/Cloud_Key.pdf&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know there are a lot more types and complexity to rocks than clouds, and clouds typing tends to be a little less useful (in part because the formation mechanisms are fairly non-distinct).  I've slowly started to see apps to lead you through plant/creature identification increasing, which is great, but are there any places we can point people to do the same for rocks?&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T07:44:50.867" LastActivityDate="2019-08-28T07:44:50.867" Title="There are cloud identification guides, are there also (guided) rock identification websites?" Tags="|meteorology|rocks|clouds|petrology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10679" PostTypeId="1" CreationDate="2017-06-24T19:42:10.243" Score="6" ViewCount="286" Body="&lt;p&gt;I found this on Lake Ontario in Canada. I was wondering is there is anything special/out of the ordinary about it? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/K17ot.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/K17ot.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8423" LastEditorUserId="6467" LastEditDate="2019-08-02T13:48:18.560" LastActivityDate="2019-08-02T13:48:18.560" Title="What are these lines on this stone?" Tags="|fossils|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10680" PostTypeId="2" ParentId="10679" CreationDate="2017-06-24T21:37:44.460" Score="15" Body="&lt;p&gt;You don't say which lake, but these are almost certainly &lt;a href=&quot;http://en.wikipedia.org/wiki/Crinoid&quot; rel=&quot;nofollow noreferrer&quot;&gt;crinoid&lt;/a&gt; stem fossils. Crinoids, or sea lilies, are &lt;a href=&quot;http://en.wikipedia.org/wiki/Echinoderm&quot; rel=&quot;nofollow noreferrer&quot;&gt;echinoderm&lt;/a&gt;s (relatives of starfish and sea urchins) that anchor themselves to the sea floor and feed on plankton.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In some crinoids, the animal's sea urchin-like &lt;em&gt;calyx&lt;/em&gt; is connected to the anchor by a long &lt;em&gt;stem&lt;/em&gt; to a &lt;em&gt;holdfast&lt;/em&gt; which anchors it. The stem part of the crinoid's &lt;a href=&quot;http://en.wikipedia.org/wiki/Endoskeleton&quot; rel=&quot;nofollow noreferrer&quot;&gt;endoskeleton&lt;/a&gt; is a stack of calcareous rings or pentagons (called &quot;ossicles&quot;) which look almost like a little spinal column. (However, vertebrates are not descended from crinoids, even though Echinoderms are &lt;a href=&quot;http://en.wikipedia.org/wiki/Deuterostome&quot; rel=&quot;nofollow noreferrer&quot;&gt;deuterostomes&lt;/a&gt;, placing them closer to chordates than arthropods or molluscs). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the animal dies, it falls into the bottom sediment and the stem can become disconnected as the sediment is compressed into limestone. Sometimes the rings stay aligned, and show assemblages like you see in your rock. Other times, all you see are disconnected rings or little pentagons, like the ones all over the rest of the rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Crinoids have been around since the &lt;a href=&quot;http://en.wikipedia.org/wiki/Ordovician&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ordovician&lt;/a&gt; period &#xA;485 million years ago, so they appear in (and sometimes entirely make up) limestones throughout the world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xh1Lj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xh1Lj.jpg&quot; alt=&quot;Crinoid fossils from Kansas&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;Source: &lt;a href=&quot;http://www.kgs.ku.edu/Extension/fossils/crinoid.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;GeoKansas&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And, just because it's there, here's &lt;a href=&quot;http://youtu.be/cZcomBnNKXg&quot; rel=&quot;nofollow noreferrer&quot;&gt; a video of a crinoid crawling across the sea floor&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2017-06-28T20:59:48.473" LastActivityDate="2017-06-28T20:59:48.473" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10683" PostTypeId="2" ParentId="10678" CreationDate="2017-06-25T10:17:11.797" Score="6" Body="&lt;p&gt;I looked through your step-by-step cloud identification guides, and they seem pretty easy. The overwhelming criterion for which cloud it is is &quot;how does it look&quot;, with the addition of the obvious &quot;is it raining&quot; or &quot;do you hear thunder&quot;. After that, you only get 10 different types.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's why it would not work for rocks:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&quot;How does it look&quot; is only one criterion out of many for rocks, and it is commonly the most misleading. A granite has many different appearances. Quartzite, limestone, basalt, can all take many forms. Weathering, alteration, fresh surfaces vs broken surfaces, desert patina or stream-polished can all change a rock's appearance completely. Grain size affects colour. Lighting affects colour.&lt;/li&gt;&#xA;&lt;li&gt;There are many more than 10 types of rocks. Basalt, gabbro, granite, rhyolite, dolomite, limestone, sandstone, shale, diorite, trachyte, ijolite, kimberlite, komatiite, eclogite, blueschist, greenschist, a conglomerate containing all of the above, and the list goes on and on. Some rocks may not even be rocks. Smelting slag, coal, hardened dung, a piece of concrete or any other kind of synthetic construction stone.&lt;/li&gt;&#xA;&lt;li&gt;The many other tests used to identify rocks may not be applied properly by people with little experience. Is the mark left by your knife on the rock really a scratch on the rock, or is it the streak of the knife? Is it really hard or is the scratch you just did was actually silt sized grains of quartz dislodged? What's &quot;heavy for its size&quot;? Everything is relative. Where a geologist sees green, brown, yellow, black or red, a non-geologist sees brown, brown, brown, brown and brown.&lt;/li&gt;&#xA;&lt;li&gt;Even professional geologists sometime disagree on what a rock is. I've seen (and been part of) so many arguments about rocks, and I have 7 years of experience in this thing. Occasionally the verdict is given by...&lt;/li&gt;&#xA;&lt;li&gt;Methods to positively identify a rock (thin sectioning, scanning electron microscopy) that are not available to the general public and probably not even to the amateur geologist.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Therefore, if a key would exist, it would be extremely complicated and pretty much useless.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2017-06-25T12:48:26.533" LastActivityDate="2017-06-25T12:48:26.533" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10686" PostTypeId="1" AcceptedAnswerId="10691" CreationDate="2017-06-25T17:06:57.770" Score="7" ViewCount="726" Body="&lt;p&gt;In 1910, George Becker published &lt;em&gt;&lt;a href=&quot;https://archive.org/details/ageearth00beckgoog&quot; rel=&quot;noreferrer&quot;&gt;The Age of the Earth&lt;/a&gt;&lt;/em&gt;, in which he used the sodium accumulation rate in the ocean to estimate the earth's age as 50 to 70 million years. We now know through various methods that the earth is much older, and as far as I can tell there hasn't been much interest from scientists in using ocean salinity as an age indicator since Becker.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One more recent paper, &lt;a href=&quot;http://static.icr.org/i/pdf/technical/The-Seas-Missing-Salt.pdf&quot; rel=&quot;noreferrer&quot;&gt;&quot;The Sea's Missing Salt&quot;&lt;/a&gt; (PDF), claims a maximum age of 62 million years after totaling sodium inputs and outputs. I've found a couple claims of measurement error floating around the Internet, but can't find any solid citations. I did find a reference to &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/0016703763900668&quot; rel=&quot;noreferrer&quot;&gt;&quot;The sodium cycle and the age of the ocean&quot;&lt;/a&gt;, but it's behind a paywall and I cannot read it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why does this salt chronometer not agree with the other dating methods? That is, what went wrong in computing the age of the earth from ocean salinity?&lt;/p&gt;&#xA;" OwnerUserId="8432" LastActivityDate="2019-04-17T11:54:16.827" Title="Why is ocean salinity not a good chronometer?" Tags="|ocean|salinity|dating|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10688" PostTypeId="1" CreationDate="2017-06-25T18:49:15.337" Score="6" ViewCount="265" Body="&lt;p&gt;I'm looking for a more or less straightforward (and not very mathematical) way to roughly estimate the flow velocity of a river based on satellite imagery (e.g. Google Earth).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In more detail: I would like to verify data on flow velocity of rivers that has been submitted to me. Usually it was taken at the side of the river (within 2-5 meters of the river bank. What features would I be looking for on Google Earth to get a rough idea if the submitted values could be correct or are completely off the edge? If there is a sandbank or if the river splits I would assume a slower flow velocity and if I can see wave-like turbulences even on satellite imagery or rivers flow together I would expect the flow velocity to increase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is no need to calculate an exact velocity, just to get an idea, let's say in the range of +/- 0.5 m/s if submitted values could be correct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any other signs I should be looking for on the satellite images that could indicate the flow velocity? Does it make sense at all or does it vary too much across small river sections anyway?&lt;/p&gt;&#xA;" OwnerUserId="8434" LastActivityDate="2017-06-25T18:49:15.337" Title="Estimate the flow velocity of a river with satellite images" Tags="|rivers|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10689" PostTypeId="2" ParentId="10593" CreationDate="2017-06-25T19:04:35.707" Score="3" Body="&lt;p&gt;A geophone (type of seismometer) contains a coil of wire, wrapped on a mass, surrounded by a magnet. As the Earth moves we assume the mass stays still due to inertia and this changing magnetic field will produce a current in the coil of wire. This current is measured as a voltage and relates to the rate of change of displacement of the Earth with respect to time or:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;v \propto \frac{dx}{dt}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where v is voltage, and $\frac{dx}{dt}$ is the velocity of ground motion. Correct me if I'm wrong but the difference in seismometers eg. MEMS accelerometers (acceleration) vs geophone (velocity) is their frequency response.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.crewes.org/ResearchLinks/GraduateTheses/2008/Hons-MSc-2008.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.crewes.org/ResearchLinks/GraduateTheses/2008/Hons-MSc-2008.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6997" LastActivityDate="2017-06-25T19:04:35.707" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10690" PostTypeId="1" CreationDate="2017-06-26T00:36:18.247" Score="5" ViewCount="64" Body="&lt;p&gt;I'm a flight instructor looking for a better way to drive home the dangers related to flying in and around thunderstorms (TS).  The FAA has mountains of operational guidance for airmen regarding TS avoidance but I'm looking for a punchy way to make the point stick with a technically correct comparison to a known quantity.  An example of what I'd like to have is:&lt;br&gt;&#xA;&quot;Think of it this way: over the course of 15 minutes, an average TS will release the energy roughly equal to //a well known event//.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Published guidance is basically, &quot;TS are really, &lt;em&gt;really&lt;/em&gt; dangerous.  Like, really...for real.  Up and down drafts can exceed 60mph and momentary jolts can easily exceed aircraft design limits [+3.8G and -1.5G for a typical general aviation plane].  Only fly on the upwind side and even then stay 20mi away because TS have been known to fling hail the size of watermelons miles downrange.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The technical guidance that is published is not meant for flight students and few pilots, even professionals, care about weather enough to learn more that what is required to pass tests.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Question: how much energy is dissipated (from maturity to dissipation) through the lifecycle of a TS? &lt;/p&gt;&#xA;" OwnerUserId="6203" LastEditorUserId="6203" LastEditDate="2019-07-11T11:53:28.087" LastActivityDate="2019-07-11T11:53:28.087" Title="Energy Released From Thunderstorms" Tags="|thunderstorm|convection|hazardous|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="10691" PostTypeId="2" ParentId="10686" CreationDate="2017-06-26T10:48:31.457" Score="7" Body="&lt;p&gt;A good chronometer is one that satisfies the following conditions:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;We know exactly how much it had of something when it began&lt;/li&gt;&#xA;&lt;li&gt;We know exactly the rate of the accumulation of the thing, and the rate is constant.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;For example, U-Pb dating in zircon is an excellent chronometer. We know exactly how much Pb is in zircon when it crystallises (= none) and we know exactly the rate of Pb accumulation by radioactive decay of U (with two separate isotopes, not one! Rejoice!).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, sodium in the ocean is a terrible chronometer. First of all, we don't have full understanding of how and when the ocean formed, let alone how much sodium they contained in the beginning. In contrast to Pb in zircon that starts with zero and goes up, the amount of sodium in the ocean is a function of many variables. These variables change with time. How much sodium do rivers input into the ocean? Depends. During orogenic periods quite a lot. During other periods less than a lot. Volcanic eruptions? Periods such as the Siberian or Deccan traps surely input a lot, but what about other periods? Removal of sodium is also non a constant process. As bon said in the comments, you have mass removal events such as the Messinian crisis. Sodium lost in ocean floor alteration is a function of how much seafloor spreading you have at that time, and the rest of the ocean chemistry. All this changes throughout geological time. The rate is not constant!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The paper that you linked to from the Institute for Creation Research has a long list of inputs and outputs of sodium and attempts to quantify it. First of all, I would be skeptical of anything coming out of there, because religiously motivated people tend to cherry-pick the data that fits their belief. But ignore that, even if their data is 100% correct, it is still correct for today. For now. As mentioned before, the input and output fluxes change drastically over time. It is impossible to assume a constant rate for that!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quoting from that paper:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It is God’s world that we are studying by scientific &#xA;  methods. It is God’s handiwork that we are learning &#xA;  about through those studies. God deserves to be &#xA;  praised  and  honoured—and  believed—for  what &#xA;  we  have  been  able  to  learn  about  his  world.  If &#xA;  our careful study of God’s world brings us false &#xA;  or unreliable information, then what can it mean &#xA;  for the Psalmist to sing, “The heavens are telling &#xA;  the glory of God; the skies proclaim the work of his &#xA;  hands.”?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Other than the fact that this passage does not belong in a scientific paper, it mentions the scientific method. Well, they fail at the scientific method because they make assumptions that make their entire study invalid.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;2019 EDIT&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A &lt;a href=&quot;https://doi.org/10.1038/s41467-018-07955-8&quot; rel=&quot;nofollow noreferrer&quot;&gt;new open access paper&lt;/a&gt; shows that quite a lot of chlorine ends up in subduction zones, and removed from the oceans. As there are different subduction fluxes throughout geological time, this is another reason for salinity being a bad chronometer.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2019-04-17T11:54:16.827" LastActivityDate="2019-04-17T11:54:16.827" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="10693" PostTypeId="1" AcceptedAnswerId="10738" CreationDate="2017-06-26T16:41:22.763" Score="6" ViewCount="972" Body="&lt;p&gt;I recently heard an anecdote about cloud-to-ground lightning striking an area where some kids were playing 20 seconds prior. They experienced their hair rising which would indicate there is a significant voltage preceding such strikes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I assume that a common multimeter would indicate a very high voltage between the ground and a cloud which is about to produce a ground strike (and it would facilitate the strike).  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Would there be some voltage between the ground and, say, 2-3 meters in the air?&lt;/li&gt;&#xA;&lt;li&gt;How long before the strike would this voltage become noticeable (significant relative to noise)?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="8438" LastEditorUserId="2470" LastEditDate="2017-06-27T03:06:45.110" LastActivityDate="2018-06-01T02:42:36.637" Title="Can a voltage difference precede cloud-to-ground lightning, and can it be measured over a short distance?" Tags="|lightning|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10694" PostTypeId="1" CreationDate="2017-06-26T18:27:00.463" Score="3" ViewCount="76" Body="&lt;p&gt;In oceanography, is there any particular reason why choosing large eddy simulations in stead of RANS (regardless of the type of flow)? In both cases, 2d simulations would be used (shallow water model).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the pros and contras, in general, of both approaches?&lt;/p&gt;&#xA;" OwnerUserId="8439" LastActivityDate="2022-12-27T21:03:08.990" Title="Reasons for choosing LES in stead of RANS models?" Tags="|ocean|oceanography|numerical-modelling|fluid-dynamics|turbulence|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10695" PostTypeId="1" CreationDate="2017-06-26T20:37:37.067" Score="10" ViewCount="2924" Body="&lt;p&gt;Please excuse me if Earth Science is not the correct place to ask this question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I read a New York Times article about increasing &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; levels in the atmosphere: &quot;&lt;a href=&quot;https://www.nytimes.com/2017/06/26/climate/carbon-in-atmosphere-is-rising-even-as-emissions-stabilize.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Carbon in Atmosphere Is Rising, Even as Emissions Stabilize&lt;/a&gt;&quot; (26 June 2017)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the article, there are not enough &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; monitoring stations for scientists to have a detailed understanding of where &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; is being emitted/absorbed (e.g. by landmasses and oceans)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This got me thinking, would it be possible to design a dual-use product that integrates a &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; sensor (e.g. a solar powered garden lamp) from which we could crowd source &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; data for scientists? Perhaps a bit naive, since the sensors may not be accurate enough for scientific studies, and if it's a consumer product they would likely have a dense install base in metropolitan areas and less in the countryside/oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But that isn't the biggest flaw in this idea. No, that came when I looked up &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; sensor prices:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pI8mK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pI8mKm.jpg&quot; alt=&quot;CO2 sensors - Digikey&quot;&gt;&lt;/a&gt; (click for full size)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was able to find some Arduino compatible sensors from a Google search for around 50USD at the low end, but looking at electronics distributors, a more reasonable price for a raw &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; sensor seems to be at least 70USD.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Carbon Monoxide detectors which you are encouraged to install in your home are much less expensive!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GGWWo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GGWWom.png&quot; alt=&quot;Carbon Monoxide detectors - Amazon&quot;&gt;&lt;/a&gt; (click for full size)&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;How can it be that &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; sensors are so expensive compared to CO detectors? &lt;/li&gt;&#xA;&lt;li&gt;Is this due to the fact that carbon monoxide sensors use a detection&#xA;method which cannot accurately determine the PPM of CO?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="8441" LastEditorUserId="2470" LastEditDate="2020-01-02T18:58:08.277" LastActivityDate="2021-09-22T11:57:14.913" Title="Why are CO2 sensors so expensive when CO sensors aren't?" Tags="|climate-change|co2|instrumentation|" AnswerCount="4" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="10696" PostTypeId="1" CreationDate="2017-06-27T03:02:51.863" Score="4" ViewCount="50" Body="&lt;p&gt;I have calculated the mass of the storm cloud for Hurricane Sandy (year 2012, in the United States of America). The dimensions of Hurricane Sandy of 1800 km in diameter and 13 km in height. Considering the density of the storm cloud multiplied by its volume. However the rain that I drop is much smaller than the rain that I would expect to spill over the territory hit by the storm. The mass, which I get for Hurricane Sandy (2012 U.S.A.) is 3.25x10^4 kg/m^2  . I would appreciate the help that would allow me an approach to solve my problem.&lt;/p&gt;&#xA;" OwnerUserId="7513" LastActivityDate="2017-06-27T03:02:51.863" Title="Is there any way to estimate, what is the percentage of the mass of a storm cloud that turns into rain?" Tags="|tropical-cyclone|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10697" PostTypeId="1" CreationDate="2017-06-27T07:00:40.237" Score="5" ViewCount="302" Body="&lt;p&gt;Very rarely in the USA Northern Mid West, maybe once a year at most, I will see a very smooth, concave cloud floating over the sky that looks exactly like a lenticular cloud, and only a few minutes, it starts to dissipate. What would explain this phenomena?  &lt;/p&gt;&#xA;" OwnerUserId="8444" LastEditorUserId="595" LastEditDate="2017-06-27T20:47:30.160" LastActivityDate="2017-06-27T20:47:30.160" Title="Why do I occasionally see a lenticular cloud when there's no mountains for hundreds of miles?" Tags="|meteorology|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10698" PostTypeId="2" ParentId="7390" CreationDate="2017-06-27T12:27:48.633" Score="3" Body="&lt;p&gt;Instead of the Nagy prism formula, I suggest you to use the formula quoted in the following paper:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;B. Banerjee, S.P. Das Gupta (1977): &lt;br&gt;&#xA;  &quot;Gravitational attraction of a rectangular parallelepiped&quot; &lt;br&gt;&#xA;  Geophysics, vol. 42, n. 5, pp. 1053-1055 &lt;br&gt;&#xA;  doi: &lt;a href=&quot;http://dx.doi.org/10.1190/1.1440766&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.1190/1.1440766&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I wrote, in Fortran, a TC program based on that formula. If you read the paper you better understand why the algorithm proposed by Banerjee-das Gupta is easier to program, but in any case, I would like to point out some features that are described at the pp. 1055:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1)&quot;...our expression contains only a tan inverse term facilitating computer work in all respects&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2)&quot;The argument of the tan inverse term of our expression is simpler than the argument of sin inverse term in Nagy’s formula&quot;...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3)&quot;...in the Nagy's formula when the signs of x1 and x2, for example, are opposite (i.e., the y-axis is crossed), the prism is divided in two, and the integral is separately evaluated from 0 to x1, and 0 to x2, and finally they are added. In this process, some logical control is required in programming his formula. But from our expression (3), it easily follows that separation of the r.h.s. term into two is not required; similarly, when the x-axis is crossed or both x- and y-axes are crossed. This is because the signs of x’s and y’s are automatically taken cam of in our subroutine&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The formula to be programmed is quoted at pp. 1055 n° 3), but in any case I could provide you the code (in Fortran) that I wrote 30 years ago writing to palmieri.gravimetry@libero.it&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kind regards and best wishes to all, Francesco&lt;/p&gt;&#xA;" OwnerUserId="8445" LastEditorUserId="6" LastEditDate="2017-06-28T11:04:33.757" LastActivityDate="2017-06-28T11:04:33.757" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10699" PostTypeId="1" AcceptedAnswerId="10703" CreationDate="2017-06-27T13:02:23.567" Score="7" ViewCount="738" Body="&lt;p&gt;On Google Maps I just found a drain east of Newfoundland:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IGlnp.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IGlnp.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More details at &lt;a href=&quot;https://www.scribblemaps.com/maps/view/What_is_that/Jafix1&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.scribblemaps.com/maps/view/What_is_that/Jafix1&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I wonder what that could be?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I heard about issues from different datasources which can occur when Google mixes data from NOAA or other sources with their own. Or could that be issued by a giant ice mountain drifting southwards? Or from the last ice age? &lt;/p&gt;&#xA;" OwnerUserId="8446" LastEditorUserId="595" LastEditDate="2017-06-27T20:46:06.110" LastActivityDate="2017-06-27T21:17:06.707" Title="What is that drain east of newfoundland" Tags="|ocean|oceanography|atlantic|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10700" PostTypeId="1" AcceptedAnswerId="10706" CreationDate="2017-06-27T13:17:04.043" Score="2" ViewCount="226" Body="&lt;p&gt;Looking through different literature articles and books concerning seismic inversion - mostly post-stack - phrases like &quot;trace-based&quot; and &quot;model-based&quot; keep appearing. I know that model-based in when lower-frequency info from either stacking velocities or low-pass sonic/rho logs are used. However, I do not know what trace-based inversion means or how it's performed. Can someone please help me with this?&lt;/p&gt;&#xA;" OwnerUserId="8447" LastEditorUserId="6" LastEditDate="2017-06-27T13:23:08.490" LastActivityDate="2017-06-29T02:01:34.787" Title="What is trace-based seismic Inversion" Tags="|geophysics|seismic|inversion|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10701" PostTypeId="2" ParentId="10699" CreationDate="2017-06-27T13:26:21.603" Score="2" Body="&lt;p&gt;I can't see there being any physical cause - the water depths are too great for an ice mountain and the feature cross-cuts other geological features. Plus, it's not aligned with either the spreading axis of the mid Atlantic ridge or normal to it. That means that it is highly unlikely to be a fault or a hotspot track.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given that, some sort of processing artifact seems most likely.&lt;/p&gt;&#xA;" OwnerUserId="8217" LastEditorUserId="8217" LastEditDate="2017-06-27T21:17:06.707" LastActivityDate="2017-06-27T21:17:06.707" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10702" PostTypeId="1" CreationDate="2017-06-27T14:33:32.530" Score="3" ViewCount="77" Body="&lt;p&gt;I've got a phenomenon of interest, $y$.  It is determined in large part by the weather.  Naturally, one becomes interested in what climate change may do to $y$, so one fits a model of the form $y = f(\mathbf{X}) + \epsilon$, where $\mathbf{X}$ is a potentially high-dimensional representation of historical weather.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get a sense of impacts into the future, one uses the fitted model $\hat{f}$ applied to (downscaled) GCM projections of weather.  Given uncertainty in which model provides the most faithful representation of the distribution of weather given CO2, one should compute a distribution of $\hat{y}$ as &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$\hat{f}(GCM_1)$&lt;/li&gt;&#xA;&lt;li&gt;$\hat{f}(GCM_2)$&lt;/li&gt;&#xA;&lt;li&gt;$\hat{f}(GCM_3)$&lt;/li&gt;&#xA;&lt;li&gt;$\vdots$&lt;/li&gt;&#xA;&lt;li&gt;$\hat{f}(GCM_k)$&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;A few questions:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;GCMs get some things badly wrong, like convective precipitation.  Is it good practice to make sure that your model $f$ and your training data $\mathbf{X}$ represent things like convective precip at an appropriate level of coarseness, such that the GCM can be roughly &quot;correct&quot;?  For example, should I only use monthly summaries of precip from a GCM, even if the GCM's raw output gives it to me sub-daily?  What are some other examples of things that GCMs don't do well, that one might consider coarsening?&lt;/li&gt;&#xA;&lt;li&gt;One shouldn't average GCM output across multiple models, obviously.  But it makes more sense to average $\hat{y}_{GCM_1}, \hat{y}_{GCM_3}, \hat{y}_{GCM_3}, \dots, \hat{y}_{GCM_k}$.  But should this be a simple average, or should the average be weighted somehow to account for the fact that some models are more similar to one another than other models?  And how would this be practically done, given that the GCM's are so high-dimensional that it becomes impossible to calculate distance metrics?&lt;/li&gt;&#xA;&lt;li&gt;Given that historical simulations exist, one can compute a &quot;backcast&quot; projection $\tilde{y} = \hat{f}(GCM_k^{historical})$, and then compute a ``bias'' term $B = E[\tilde{y}] - E[y]$.  (Naturally one would use a difference in means, rather than a pointwise difference, because GCMs attempt to model the distribution of the weather, rather than realized weather.)  If the estimated bias $B$ is nontrivial, should I add it to my projections, forming $\hat{y}_{BC} = \hat{y} - B$?  Or is there a better way to achieve the same end?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="545" LastActivityDate="2017-06-27T14:33:32.530" Title="Good practices and pitfalls when fitting models $y = f(weather)$ and predicting $\hat{y} = \hat{f}(GCM)$" Tags="|climate|climate-change|climate-models|statistics|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10703" PostTypeId="2" ParentId="10699" CreationDate="2017-06-27T14:39:14.067" Score="12" Body="&lt;p&gt;It is an artifact of the processing software when it processes Multibeam Bathymetric Survey data. &#xA;You can get the lines of the different surveys from &lt;a href=&quot;https://www.ngdc.noaa.gov/&quot; rel=&quot;noreferrer&quot;&gt;NGBC&lt;/a&gt; at NOAA (&lt;a href=&quot;https://maps.ngdc.noaa.gov/viewers/bathymetry/&quot; rel=&quot;noreferrer&quot;&gt;https://maps.ngdc.noaa.gov/viewers/bathymetry/&lt;/a&gt;). As you can see in the image below both lines you see in your example correspond to multibeam data. In the area there is a fair amount of single-beam bathymetry, but the multibeam bathy is often weighted differently creating artifacts in some cases.&#xA;The GEBCO bathymetry does not contain the artifact.  &lt;a href=&quot;https://i.stack.imgur.com/BpaW1.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BpaW1.jpg&quot; alt=&quot;Gebco bathy&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2017-06-27T14:39:14.067" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10706" PostTypeId="2" ParentId="10700" CreationDate="2017-06-28T02:23:29.003" Score="3" Body="&lt;p&gt;I too have found this nomenclature rather confusing.  I am pretty sure that trace-based inversion is merely where each seismic trace is inverted independently of surrounding traces. This would take into account most deterministic/probabilistic inversion types (e.g. model, coloured, sparse, etc). In contrast, geostatistical inversion would not strictly be trace-based inversion, as it uses a spatial and temporal variogram to takes into account the expected results of surrounding traces during the inversion, even though it does invert on a trace-by-trace basis. Confusing. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following paper describes trace and geostatistical inversion methods:&#xA;&lt;a href=&quot;http://www.cgg.com/data/1/rec_docs/3037_Geostatistical_Inversion_San_Jorge_SEG_2003.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Germán Merletti, and Julio Hlebszevitsch. 2003. Geostatistical Inversion for the Lateral Delineation of Thin Layer Hydrocarbon Reservoirs: A Case Study in San Jorge Basin, Argentina. SEG 2003.&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've found the following paper very useful for understanding seismic inversion (geostatistical isn't discussed, though): &#xA;&lt;a href=&quot;http://csegrecorder.com/articles/view/model-based-seismic-inversion-comparing-deterministic-and-probabilistic&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dennis Cooke and John Cant. 2010. Model-based Seismic Inversion: Comparing deterministic and probabilistic approaches. CSEG Recorder, Vol. 35, No. 4.&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="777" LastEditorUserId="777" LastEditDate="2017-06-29T02:01:34.787" LastActivityDate="2017-06-29T02:01:34.787" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10707" PostTypeId="2" ParentId="8211" CreationDate="2017-06-28T03:00:50.893" Score="0" Body="&lt;p&gt;It is possible for a cloud to rain itself out. But it then takes some time for the rain to fall to the ground. By the time the rain reaches the ground, the cloud is no longer there. This is rare, but it can happen.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastEditorUserId="8382" LastEditDate="2017-07-03T22:22:31.913" LastActivityDate="2017-07-03T22:22:31.913" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10710" PostTypeId="1" CreationDate="2017-06-28T10:41:50.353" Score="3" ViewCount="1020" Body="&lt;p&gt;How does one practically compute the kinetic energy spectra from a timeseries of u- and v- Cartesian components of ocean current velocity ($m s^{-1}$) obtained from an Acoustic Doppler Current Profiler (ADCP) moored on the seabed?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do you: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) compute the spectra of each u- and v- components and then calculate the resulting kinetic energy from the spectra in the frequency domain? i.e. $KE(f) = 0.5\times(u_{(f)}^2 + v_{(f)}^2)$; where $KE_{(f)}$ is the kinetic energy spectrum per unit frequency and similarly $u_{(f)}$ and $v_{(f)}$ are the u- and v- power spectra?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;or; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) compute the kinetic energy $KE = 0.5\times(u_{(t)}^2 + v_{(t)}^2)$, where $u_{(t)}$ &amp;amp; $v_{(t)}$ are the current velocity timeseries and then calculate the power spectral density (i.e. using Matlab's &lt;em&gt;pwelch&lt;/em&gt;) of the resulting KE?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any guidance with the theory or practical calculation would be very much appreciated. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="5095" LastActivityDate="2017-06-29T22:57:08.013" Title="How to calculate the kinetic energy spectra from ocean current timeseries?" Tags="|oceanography|ocean-currents|matlab|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10712" PostTypeId="2" ParentId="9688" CreationDate="2017-06-28T14:03:47.547" Score="0" Body="&lt;p&gt;The meteorological application of vertically integrated moisture flux convergence (MFC) is very well explained by Banacos and Schultz (2004), so I will not repeat their words.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But in general words, MFC (only the divergence term, times -1) may be used to estimate precipitation, assuming that local variations of moisture are mainly due to advection and evaporation is nearly null in regions of substantial precipitation and/or saturated air.&lt;/p&gt;&#xA;" OwnerUserId="8396" LastActivityDate="2017-06-28T14:03:47.547" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10713" PostTypeId="2" ParentId="9634" CreationDate="2017-06-28T14:44:36.230" Score="3" Body="&lt;p&gt;The easy answer is to use finite difference. Which one is entirely your choice. For example, I'll choose a simple centered difference scheme.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You say you have a grid, and your point ($x$,$y$) is at the ith and jth gridpoint, where i indicates the left-right index on the grid and j indicates the north-south index on the grid. Therefore $u$ and $v$ can be expressed as $u(x_{i,j},y_{i,j})$ and $v(x_{i,j},y_{i,j})$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\frac{du}{dx}\approx\frac{\Delta u}{\Delta x}=\frac{u(x+\Delta x,y)-u(x-\Delta x,y)}{\Delta x}=\frac{u(x_{i+1,j},y)-u(x_{i-1,j},y)}{x_{i+1,j}-x_{i-1,j}}=\frac{u_{i+1,j}-u_{i-1,j}}{x_{i+1,j}-x_{i-1,j}}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A similar process can be applied to the v component, just change the index, and the variables&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-06-28T14:44:36.230" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10716" PostTypeId="2" ParentId="10695" CreationDate="2017-06-29T11:44:07.300" Score="3" Body="&lt;p&gt;I think the core of the answer should lie in what was already stated in the comments. These detectors are not scientific instruments. For air quality monitoring &lt;a href=&quot;https://www.thermofisher.com/order/catalog/product/48I&quot; rel=&quot;nofollow noreferrer&quot;&gt;much more sophisticated analyzers&lt;/a&gt; are needed to measure the concentration of the gases. The example in the link works on a basis of gas filter (filled with CO) and it can just as well be used for &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; if you fill the filter with this gas instead. Analyzers like this can cost around 20 000 USD (very rough estimate based on prices in my national currency).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is what is relevant to Earth Science SE, the questions about the price should really be asked on a different site.&lt;/p&gt;&#xA;" OwnerUserId="6643" LastEditorUserId="2470" LastEditDate="2020-01-02T19:00:30.800" LastActivityDate="2020-01-02T19:00:30.800" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="10717" PostTypeId="1" AcceptedAnswerId="10719" CreationDate="2017-06-29T12:48:04.657" Score="5" ViewCount="369" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Prevailing_winds&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia entry for prevailing winds&lt;/a&gt; notes (in my understanding) that the prevailing wind direction is determined solely by the mode of the directions. They note another qualifier called 'dominant wind' which should give the direction of the strongest wind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it feels a bit counter-intuitive that if we had (an example) over 8h a wind from the east at 2m/s and after that a 10m/s wind from the north for 4h, that the prevailing wind direction would still be east. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Based on the above example, would the prevailing wind direction be east? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the term 'dominant wind' (with a northerly direction) used in common meteorology, and would that be (in the above example) northerly?&lt;/p&gt;&#xA;" OwnerUserId="8425" LastActivityDate="2017-07-29T23:16:46.880" Title="Prevailing Winds: Is the speed relevant?" Tags="|meteorology|statistics|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10718" PostTypeId="2" ParentId="10717" CreationDate="2017-06-29T14:04:16.767" Score="1" Body="&lt;p&gt;I think when determining the dominant or prevailing wind direction it is mainly used to describe a longer term than a day (perhaps a month, a year or the climatology in that spot). In my opinion the prevailing wind in the sense you challenge it might be a bit subjective to the one who is assessing it or coding it from a time series. By looking at a wind rose (a figure for example in &lt;a href=&quot;https://knowledge.autodesk.com/search-result/caas/CloudHelp/cloudhelp/B3/ENU/Vasari-UsersGuide/files/GUID-2AACFEA1-16BD-4A01-BD75-81B12E56A57C-htm.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;), that has the wind speeds and directions as a function of occurrence in the radial scale, you could interpret that the prevailing wind could be to the direction that has the most occurrence or another person might say that it is the other maximum that is slightly wider but not that sharp and could even have stronger winds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example from continuous wind data lets say for wind direction resolution 0.5 degrees there might be a lone spike that has the most occurrence, but judging by the eye another maximum is much wider and clearer. Most wind roses for readability the wind directions are even binned (south, south-east..) that flattens the lone spikes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To conclude: different people may interpret the data differently when dealing with borderline cases.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastActivityDate="2017-06-29T14:04:16.767" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10719" PostTypeId="2" ParentId="10717" CreationDate="2017-06-29T16:04:54.513" Score="3" Body="&lt;p&gt;Part of the complication goes to two separate definitions for the word:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;prevailing:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;To be frequent (&lt;a href=&quot;https://www.merriam-webster.com/dictionary/prevailing&quot; rel=&quot;nofollow noreferrer&quot;&gt;Miriam-Webster&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The most frequent, the most occurring wind direction in your example, even if weak, is east.  So that would be the prevailing wind, as that's the definition we generally use in meteorology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So don't think of it as&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Having superior power or influence (&lt;a href=&quot;http://www.dictionary.com/browse/prevailing&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dictionary.com&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;as indeed, that'd become a bit more subjective of a concept.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sometimes you may hear about the average direction (which would be east-northeast in your example).  So perhaps that's more what you're wishing for?  Of course if you have an east wind for half the day and a west wind for half the day, the average wind direction would be either north or south.  Or, if instead of treating direction and speed differently, you took the vector average... you'd have a mean windspeed of nothing!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looks like &lt;a href=&quot;https://math.stackexchange.com/questions/44621/calculate-average-wind-direction&quot;&gt;this MathSE question&lt;/a&gt; fairly discusses some of the benefits and troubles with different methods of summarizing wind direction... which line up closely with the more general disparities of each of mean, median, and mode.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alternatively, wind roses can be much more informative and enticing.  They give both an indication of the directions (by the length of the bars in each direction) and the intensity (color coded).  You can find things, such as: in Colorado Springs in May (as shown below), winds aren't from the southwest very often... but when they are, they tend to be fairly strong (whereas when winds are from about east, as is more common, they're typically quite light):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/vyCH2.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vyCH2.gif&quot; alt=&quot;Colorado Springs May&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looks like you can make some pretty snazzy/customizable recent wind rose plots of locations around the world at the &lt;a href=&quot;http://mesonet.agron.iastate.edu/sites/locate.php?network=ID__ASOS&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iowa Environmental Mesonet site&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;But the take home is: in meteorology we typically define prevailing wind as simply the most common direction, with no consideration of the speed distribution.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-07-29T23:16:46.880" LastActivityDate="2017-07-29T23:16:46.880" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10720" PostTypeId="2" ParentId="10695" CreationDate="2017-06-29T16:48:54.923" Score="2" Body="&lt;p&gt;First you need to make the difference between a detector and a sensor, while the first one only shows that some gas is present, the second has to show the amount of gas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Usually a sensor needs calibration, where you must give two points with different concentrations, this is not easy and you need a known source of concentration. Also this means that a sensor requires more electronics for its human-machine interaction.&lt;br&gt;&#xA;A detector only needs to trigger an alarm, nothing else.&lt;/p&gt;&#xA;" OwnerUserId="5004" LastActivityDate="2017-06-29T16:48:54.923" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10721" PostTypeId="2" ParentId="10717" CreationDate="2017-06-29T22:31:30.163" Score="-1" Body="&lt;p&gt;Prevailing Wind is predominantly related to the most common wind direction and how long in a period of time the wind is blowing in this direction.&lt;/p&gt;&#xA;" OwnerUserId="7924" LastActivityDate="2017-06-29T22:31:30.163" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10722" PostTypeId="2" ParentId="10710" CreationDate="2017-06-29T22:57:08.013" Score="1" Body="&lt;p&gt;Do you get much different results if you do both ways?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think if you want the kinetic energy spectrum, use your second method. Some separately compute velocity and KE spectra, e.g., figure 2 of &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/2009JPO4330.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://journals.ametsoc.org/doi/pdf/10.1175/2009JPO4330.1&lt;/a&gt; (DP Wang et al, JPO, Apr 2010). Comparing velocity and KE spectra, the KE spectra looks similar to the more powerful velocity spectrum, especially at low frequencies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Others use your first method (e.g., &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/JPO-D-15-0087.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://journals.ametsoc.org/doi/pdf/10.1175/JPO-D-15-0087.1&lt;/a&gt;, Rocha et al, JPO, Feb 2016)&lt;/p&gt;&#xA;" OwnerUserId="8468" LastActivityDate="2017-06-29T22:57:08.013" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10723" PostTypeId="2" ParentId="10670" CreationDate="2017-06-30T01:40:25.263" Score="5" Body="&lt;p&gt;Filtering is always a convolution of the signal. What you are doing in the frequency domain will also be manifested in the time domain. A sharp edge in frequency domain will create a long convolution in time domain. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ormsby (or trapezoidal) filters cause strong ringing if the slope is steep due to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Gibbs_phenomenon&quot; rel=&quot;noreferrer&quot;&gt;Gibbs effect&lt;/a&gt;. To reduce the ringing, make the slopes more gentle (eg 6, 12, 45, 60) or try to taper the filter slopes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it appears that you are using a strong &lt;a href=&quot;http://www.xsgeo.com/course/gain.htm&quot; rel=&quot;noreferrer&quot;&gt;AGC&lt;/a&gt;. Check if the ringing is actually a problem before smoothening the filter. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some of the ringings will also disappear if you intend to F/K filter the direct waves. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastActivityDate="2017-06-30T01:40:25.263" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10724" PostTypeId="2" ParentId="7276" CreationDate="2017-06-30T04:08:59.063" Score="2" Body="&lt;p&gt;Tropopause temperatures were unusually cold. This allowed a steep enough lapse rate despite cool sea surface temperatures of 68 degrees F, and was one of the factors that helped Alex to form despite such cool sea surface temperatures. Hurricanes are heat engines with the hot source at the ocean surface and the cold sink at the tropopause. Thus an unusually cold tropopause can compensate to some extent for sea surface temperatures lower than the usual minimum value of 78 degrees F required for hurricane formation.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-06-30T04:08:59.063" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10725" PostTypeId="2" ParentId="10644" CreationDate="2017-06-30T19:43:01.003" Score="2" Body="&lt;p&gt;See the image below. In the picture, the San Andreas Fault &lt;em&gt;dip&lt;/em&gt; is nearly 90 degrees or exactly vertical; The &lt;em&gt;strike&lt;/em&gt; is pointing North.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most normal faults and reverse faults (such as the Sierra Madre) are not vertical, but rather dip in either direction. (In the picture the Sierra Madre appears to have a dip of about 45 degrees).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In real life, the dip of the San Andreas is not perfectly vertical, but is variable, depending on where in California you are.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Strike and dip can be measured using a Brutton Compass.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EdgcA.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EdgcA.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8472" LastEditorUserId="8472" LastEditDate="2017-06-30T21:09:41.853" LastActivityDate="2017-06-30T21:09:41.853" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10726" PostTypeId="1" CreationDate="2017-07-01T01:45:17.850" Score="5" ViewCount="873" Body="&lt;p&gt;Is there a theoretical physical limit that we can calculate with regards to Tornado formation? At what size and strength is a hypothetical tornado &lt;em&gt;physically&lt;/em&gt; impossible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The largest tornado in recorded history was the El Reno tornado at 2.6 miles wide on May 31, 2013. The fastest wind speeds ever recorded were 301 miles per hour in Moore OK May 3, 1999.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*Edit for clarity:&#xA;How would the physical properties of air constrain the size and strength of a tornado and can we estimate the largest and strongest tornado physically possible?&lt;/p&gt;&#xA;" OwnerUserId="8473" LastEditorUserId="8473" LastEditDate="2017-07-01T02:45:18.897" LastActivityDate="2017-07-01T02:45:18.897" Title="What are the Theoretical Limits for Tornado Size and Strength" Tags="|meteorology|atmosphere|tornado|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10727" PostTypeId="1" AcceptedAnswerId="10736" CreationDate="2017-07-01T13:55:47.507" Score="4" ViewCount="323" Body="&lt;p&gt;In different reanalysis products (&lt;a href=&quot;http://apps.ecmwf.int/datasets/data/era20c-daily/levtype=sfc/type=an/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ERA 20C&lt;/a&gt; and &lt;a href=&quot;https://www.esrl.noaa.gov/psd/data/gridded/data.20thC_ReanV2.monolevel.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA/OAR/ESRL/PSD 20th Century&lt;/a&gt; daily data specifically) one can find the following variables:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Total column water (ERA) &lt;/li&gt;&#xA;&lt;li&gt;Total column rain water (ERA)&lt;/li&gt;&#xA;&lt;li&gt;Total column water vapor (ERA)&lt;/li&gt;&#xA;&lt;li&gt;Total column cloud liquid water (ERA)&lt;/li&gt;&#xA;&lt;li&gt;Cloud water content (NOAA)&lt;/li&gt;&#xA;&lt;li&gt;Precipitable water content (NOAA)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How are they calculated?&lt;/strong&gt; What are the differences between them? Could you please cite a reference or book in which this is explained in details?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which of these may serve as a best approximation to represent large-scale patterns of rainfall (monsoonal cycles)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which of these is the vertically integrated specific moisture?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are any of these equivalent to the vertically integrated moisture flux divergence as an approximation for precipitation, as in &lt;a href=&quot;http://www.squallwx.com/papers/MFC2005.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Banacos and Schultz (2005)&lt;/a&gt;?&lt;/p&gt;&#xA;" OwnerUserId="8396" LastEditorUserId="8396" LastEditDate="2018-05-11T08:58:25.103" LastActivityDate="2018-05-11T08:58:25.103" Title="Single-layer water content variables" Tags="|meteorology|climate|climate-models|open-data|reanalysis|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="10728" PostTypeId="1" AcceptedAnswerId="10729" CreationDate="2017-07-01T14:35:53.530" Score="7" ViewCount="698" Body="&lt;p&gt;Linear correlation (Pearson's) is vastly applied in meteorology/climatology to assess the &lt;em&gt;relationship&lt;/em&gt; between two variables, say precipitation and SST, for example.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, we know that &lt;a href=&quot;https://en.wikipedia.org/wiki/Correlation_does_not_imply_causation&quot; rel=&quot;noreferrer&quot;&gt;correlation does not necessarily imply causation&lt;/a&gt;, mainly for two factors: there may be external factors acting on both series or &lt;a href=&quot;http://www.tylervigen.com/spurious-correlations&quot; rel=&quot;noreferrer&quot;&gt;spurious coincidences&lt;/a&gt; may also happen. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are possible and comprehensible ways, that have been used and are possible to reproduce in the Earth Sciences (Meteorology, Oceanography, Clmatology...), to go further and make a point to show that correlation &lt;em&gt;does&lt;/em&gt; imply causation in some situations?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT to make it more specific:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Imagine correlation is found between sea surface temperature (SST) in some region and rainfall in another. How to test if the variability of the two series are not being externally forced by a third party?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="8396" LastEditorUserId="8396" LastEditDate="2017-07-02T22:37:28.067" LastActivityDate="2017-07-28T12:09:03.040" Title="Correlation and causation" Tags="|meteorology|atmosphere-modelling|statistics|climatology|correlation|" AnswerCount="3" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10729" PostTypeId="2" ParentId="10728" CreationDate="2017-07-01T19:35:32.093" Score="5" Body="&lt;p&gt;Convergent cross mapping (CCM) is a recently developed tool to answer the question you've asked. It's based on tools developed in nonlinear time series analysis and dynamical systems theory. It allows you to:&lt;br/&gt;&#xA;1) determine if a causal relationship between two variables is present &lt;br/&gt;&#xA;2) establish the direction of causality&lt;br/&gt;&#xA;3) do so even in the presence of noise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for an interesting application, check out the paper &lt;em&gt;Causal feedbacks in climate change&lt;/em&gt; [&lt;a href=&quot;http://deepeco.ucsd.edu/~george/publications/15_causal_feedbacks_climate.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;van Nes et al., 2015&lt;/a&gt;], where CCM is applied to co2 and temperature based on the Vostok data sets.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: Below I've added a more detailed explanation of CCM to show the original poster that this technique does indeed answer their question, as well as to show it has a rigorous mathematical underpinning.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The general idea of convergent cross mapping is based on phase space reconstruction [&lt;a href=&quot;https://pdfs.semanticscholar.org/4039/236d89b682a2ab7aa9baaa4057707161d9be.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;F. Takens, 1981&lt;/a&gt;],[&lt;a href=&quot;https://books.google.com/books?hl=en&amp;amp;lr=&amp;amp;id=dtTvBwAAQBAJ&amp;amp;oi=fnd&amp;amp;pg=PR5&amp;amp;dq=Analysis+of+Observed+Chaotic+Data&amp;amp;ots=SAcjQgvrXc&amp;amp;sig=E0l97Yu_wDvY3SiTKnNHIZSt0Ow#v=onepage&amp;amp;q=Analysis%20of%20Observed%20Chaotic%20Data&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;H. Abarbanel, 1996&lt;/a&gt;]. Numbers 1 through 5 explain the idea behind phase space reconstruction, which is needed to understand CCM. Numbers 6 through 8 very briefly explain CCM. References are listed at the bottom for more depth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) A physical system that is described by a set of equations (e.g. conservation of mass, momentum, etc) has a phase space. The solution to the system of equations is a trajectory through (or subset of) the phase space. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) An attractor is a subset of the phase space that the trajectories/solutions evolve toward.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) If you know the governing attractor, then you have all solutions of the system for all time. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;4) Taken’s theorem says that one can reconstruct the attractor of the system based on a single observable. For example, if temperature, pressure, and velocity are the three variables of the system, then you only need measurements from one of these variables to reconstruct the attractor of the system. &lt;a href=&quot;https://www.youtube.com/watch?v=7ucgQE3SO0o&quot; rel=&quot;nofollow noreferrer&quot;&gt;State space reconstruction&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;5) The reconstructed attractor is not exactly the “true” attractor, but it has a direct 1:1 mapping to the true attractor. &lt;a href=&quot;https://www.youtube.com/watch?v=rs3gYeZeJcw&quot; rel=&quot;nofollow noreferrer&quot;&gt;Taken's theorem&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;6) If two observables belong to the same system, then they each have a reconstructed attractor with a direct mapping to the true attractor. The reconstructed attractors also have a direct mapping to one another. &lt;a href=&quot;https://www.youtube.com/watch?v=NrFdIz-D2yM&quot; rel=&quot;nofollow noreferrer&quot;&gt;Convergent cross mapping&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;7) It is then possible to make predictions on one observable, based on the reconstructed attractor of the other observable, if they are in fact from the same attractor (causally related). &lt;a href=&quot;https://www.youtube.com/watch?v=8DikuwwPWsY&quot; rel=&quot;nofollow noreferrer&quot;&gt;Time series and attractors&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;8) Last, a series of tests/predictions with the data help to establish the direction of, strength of, and linearity of the interactions between the two variables. This is detailed in the papers [&lt;a href=&quot;http://www.uvm.edu/~cdanfort/csc-reading-group/sugihara-causality-science-2012.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;sugihara et al., 2012&lt;/a&gt;] and [&lt;a href=&quot;http://deepeco.ucsd.edu/~george/publications/15_causal_feedbacks_climate.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;van Nes et al., 2015&lt;/a&gt;].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer your question &quot;given two observed variables, how do you tell if an third variable is simply forcing the two observed variables, making them appear correlated? First, the process of phase space reconstruction would yield an estimate of the &quot;embedding dimension&quot;, which is an estimate of the dimension of the phase space (how many variables there). In the CCM framework, a one-way forcing relationship between the two known variables (v1 and v2) would be attractor for v1 can make skillful predictions of v2, but attractor v2 can not make skillful predictions for v1. Contingent upon the situation where you have an idea of what the third variable is (v3), &lt;em&gt;I think&lt;/em&gt; what you could do is the following, take the reconstructed attractor of v3 and make predictions on both v1 and v2, and show that v3 has more predictive power on v1 (compared to v2), and that v3 has more predictive power on v2 (compared to v1). I'm not sure about this though. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, if the forcing (v3) is thought to be linear, you could simply remove/detrend v3 from v1 and v2, as is done when you remove seasonality from temperature data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: There is &lt;a href=&quot;https://www.mathworks.com/matlabcentral/fileexchange/52964-convergent-cross-mapping&quot; rel=&quot;nofollow noreferrer&quot;&gt;MATLAB code&lt;/a&gt; available to mess around with this technique. I believe you can find similar codes in R as well. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;References&lt;br/&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sugihara et al., 2012, &lt;em&gt;Detecting causality in complex ecosystems&lt;/em&gt;.&lt;br/&gt;&#xA;van Nes et al., 2015, &lt;em&gt;Causal feedbacks in climate change&lt;/em&gt;.&lt;br/&gt;&#xA;Abarbanel, Analysis of Observed Chaotic Data,1996, Springer publishing. &lt;br/&gt;&#xA;Takens, 1981, &lt;em&gt;Detecting strange attractors in turbulence&lt;/em&gt;&lt;br/&gt;&lt;/p&gt;&#xA;" OwnerUserId="6221" LastEditorUserId="6221" LastEditDate="2017-07-20T18:56:38.813" LastActivityDate="2017-07-20T18:56:38.813" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="10730" PostTypeId="1" AcceptedAnswerId="10733" CreationDate="2017-07-01T20:59:20.373" Score="3" ViewCount="116" Body="&lt;p&gt;I found some huge objects that are way too big to be &lt;a href=&quot;http://www.thecanadianencyclopedia.ca/en/article/inuksuk-inukshuk/&quot; rel=&quot;nofollow noreferrer&quot;&gt;inuksuks&lt;/a&gt;, in my opinion. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The object on the right is very odd because the arms are not straight like they are in most images of inuksuks. and there are huge piles of rocks that look so unnatural. Can any geologist or anyone explain this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;These are the coordinates: left: &lt;a href=&quot;https://www.google.com.au/maps/place/68%C2%B041&amp;#39;52.5%22N+124%C2%B053&amp;#39;41.2%22W/@68.6979083,-124.8969609,1384m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d68.6979083!4d-124.8947722&quot; rel=&quot;nofollow noreferrer&quot;&gt;68°41'52.47&quot;N 124°53'41.18&quot;W&lt;/a&gt;&#xA;right: &lt;a href=&quot;https://www.google.com.au/maps/place/68%C2%B045&amp;#39;59.1%22N+125%C2%B010&amp;#39;06.8%22W/@68.7664139,-125.1707331,1367m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d68.7664139!4d-125.1685444&quot; rel=&quot;nofollow noreferrer&quot;&gt;68°45'59.09&quot;N 125°10'6.76&quot;W&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bV4lS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bV4lS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8475" LastEditorUserId="6467" LastEditDate="2019-01-12T13:42:11.050" LastActivityDate="2019-01-12T13:42:11.050" Title="Odd Inuksuk-like objects" Tags="|rocks|remote-sensing|archaeology|ground-truth|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10731" PostTypeId="2" ParentId="10728" CreationDate="2017-07-01T21:18:18.963" Score="4" Body="&lt;p&gt;I can give some examples from atmospheric science:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Wind and temperature in the vertical direction: as you increase in height, the temperature decreases due to the conservation of geopotential energy. Also the wind speed increases, due to the lack of friction.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;In data assimilation, spurious correlations are quite common, especially for large distances. Localization is one way to reduce the influence of spurious correlations.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;It is not an uncommon rule of thumb that precipitation is associated with low pressure. However, that rule of thumb does not always apply to thunderstorms, where pressure may increase in the downdraft.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;It is a known fact that pressure and temperature are proportional ($P=\rho R T$). However, if you look at hurricane data, warm air can strengthen a hurricane, according to the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Wind-induced_surface_heat_exchange&quot; rel=&quot;nofollow noreferrer&quot;&gt;wind-induced surface heat exchange&lt;/a&gt;. Also, warm advection can also lower the pressure of an extratropical cyclone.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://tylervigen.com/discover&quot; rel=&quot;nofollow noreferrer&quot;&gt;Spurious Correlations&lt;/a&gt; has a list of examples of correlations that are not many times inexplicable, though not all are relegated to earth science. For example, precipitation in South Carolina is negatively correlated with precipitation in Richland County, Wisconsin (-0.77).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-07-01T21:18:18.963" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10732" PostTypeId="2" ParentId="9811" CreationDate="2017-07-02T21:43:47.437" Score="3" Body="&lt;p&gt;There is two parts to this answer, first continental crust tends to persist and oceanic tends to be recycled. This is largely due to density, continental crust is less dense and tends to &quot;float&quot; compared to the mantle and is very difficult to push back into the mantle for remelting. Only a tiny fraction of continental crust ever gets subducted mostly as sediment on oceanic crust, so basically by piggybacking on subducting oceanic crust. This is why continent to continent convergent boundaries form mountains with no subduction, they can only push down by pushing even more material up, in effect packing together like wads of compressing clay. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second continental crust is reworked by other processes, erosion, faulting, rifting, mountain building, metamorphic processes, etc. These are regional effects and thus more random, so how much they alter can vary quite a bit from continent to continent. Exposed un-reworked continental crust is rare but this is due to the accumulation of events reworking smaller regions and the tendency of sediment covering it up. There is much more unexposed old continental crust buried under the sediment, often referred to as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Shield_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;shield&lt;/a&gt; portion of the craton, Shield is the portion of the continental crust that is not sediment and is not tectonically active (even some shield is partially metaphorically altered, but this is where you find unaltered material) There is quite of bit of ancient shield (brown in this &lt;a href=&quot;https://i.stack.imgur.com/kqRWt.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;picture&lt;/a&gt;) although it still makes up a small percentage of the overall continental crust. Even then only a fraction of it has survived all the continental cycles and is completely unaltered since the first continents formed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This image illustrates how much of the oldest continental crust is still around(purple). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sUlbM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sUlbM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically oceanic crust is guaranteed to be reworked eventually, check the age of &lt;a href=&quot;http://www.ucmp.berkeley.edu/tectonics/crustages.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;oceanic crus&lt;/a&gt;t, while continental crust has a more random factor involved meaning some in the more stable regions of some continents has not been reworked. That is why they are only small scattered areas.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2017-07-04T15:10:29.300" LastActivityDate="2017-07-04T15:10:29.300" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10733" PostTypeId="2" ParentId="10730" CreationDate="2017-07-03T03:34:12.497" Score="8" Body="&lt;p&gt;I can engage in some educated speculation about what you think you see, but I'm confident you were fooled by the shadows in the image, which are caused by a low sun angle and distorted by the terrain. These are not &lt;a href=&quot;http://icor.ottawainuitchildrens.com/node/13&quot; rel=&quot;nofollow noreferrer&quot;&gt;inuksuit&lt;/a&gt; (which is the correct plural of &lt;em&gt;inuksuk&lt;/em&gt;). They are all natural, not man-made. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's point out a few things we know and can see on the imagery:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;It's in the Low Arctic.&lt;/li&gt;&#xA;&lt;li&gt;The uplands away from the river are snow-free, except in a few pockets. There is even some greening of new tundra vegetation.&lt;/li&gt;&#xA;&lt;li&gt;There is broken-up ice along the sides of the river. &lt;/li&gt;&#xA;&lt;li&gt;The trees in the uplands all have very long shadows, so other shadows are likely to be elongated.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Together, #1, #2, and #3 tell us that it's probably early summer just after the river ice has broken up. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The tooth-like features in the left image are simply erosional remnants sticking out of the riverbank. They could be bedrock (not likely), ice wedges, unmelted permafrost, or simply dirt. They are on the outside of a meander, so the river is actively cutting into them, and so the river-facing faces are quite sheer and high compared to the slopes in between. The right side might be white because the conditions there had left the snow unmelted when the image was taken. And of course their shadows are longer because the river channel is at the bottom of the bluff. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you use Google Maps or Earth to go downriver a bit (up and to the left), you will see similar features sticking out of the riverbank, but because they're at a different angle from the features in your image, the fact that they're natural is more readily apparent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although the terrain is much less regular on the right side of the image, again the long shadows tell the tale. There are some round lumps that may be &lt;a href=&quot;http://en.wikipedia.org/wiki/Pingo&quot; rel=&quot;nofollow noreferrer&quot;&gt;pingo&lt;/a&gt;es.  The shadow that looks like a man is just a coincidental jumble of shadows from the broken terrain. If you look closely at the lump that is supposed to be the &quot;man&quot; (which would technically be an &lt;em&gt;inunnguaq&lt;/em&gt;) does not have any protrusions that correspond to the &quot;arms&quot;. The &quot;arms&quot; are the shadow of a little cliff or shelf past the lump, which is overlapped by the lump's larger shadow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1w9jf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1w9jf.jpg&quot; alt=&quot;Erwin Raisz eat your heart out&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's similar in effect to the infamous misinterpretation of a Viking orbiter image of a natural feature on Mars as a &quot;&lt;a href=&quot;https://science.nasa.gov/science-news/science-at-nasa/2001/ast24may_1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Face on Mars&lt;/a&gt;&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a good example of the complications of image interpretation, specifically, understanding the conditions under which the image was taken. It's also a good time to emphasize the importance of doing &lt;a href=&quot;http://en.wikipedia.org/wiki/Ground_truth&quot; rel=&quot;nofollow noreferrer&quot;&gt;ground truth&lt;/a&gt; when interpreting images. So when you go there, let us know what you find. &lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="1411" LastEditDate="2017-07-07T20:36:26.340" LastActivityDate="2017-07-07T20:36:26.340" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10734" PostTypeId="2" ParentId="8947" CreationDate="2017-07-03T05:38:46.880" Score="1" Body="&lt;p&gt;This is a difficult question since time of concentration ($t_c$) can in theory,  vary substantially, for two basins of equal size.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Off the top of my head, I can imagine several other variables that would be necessary to determine $t_c$: drainage density, basin relief, basin length, surface roughness (Mannings coefficient), and rainfall statistics. There's certainly others too. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found a paper titled &lt;em&gt;The characteristic time scale for basin hydrological response using radar data&lt;/em&gt; is freely available. There is a discussion of $t_c$ beginning on page 93 at bullet point number 2. They cite other papers in their discussion that would be worth tracking down and reading. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note they present an empirical equation for $t_c$:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$t_c=5.4\left(\frac{L}{S^{0.5}}\right)^{0.75}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;L&lt;/em&gt; is basin length, and &lt;em&gt;S&lt;/em&gt; is slope/relief. It's weird, yet I'm not surprised since it's empirical. Evidently the 5.4 has dimensions of $time$ and $length^{-0.75}$. It's hard to imagine that this equation would actually be useful.&lt;/p&gt;&#xA;" OwnerUserId="6221" LastActivityDate="2017-07-03T05:38:46.880" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10735" PostTypeId="1" CreationDate="2017-07-03T07:36:51.000" Score="4" ViewCount="1209" Body="&lt;p&gt;I want to setup a mesoscale weather prediction model (WRF or something else) to work with NCEP/GFS meteorological input data with resolution of 0.25deg. My question is how to choose a proper size for the parent domain, considering the resolution of the input data. In my case GFS resolution is around 20km in mid latitudes, is it necessary for my parent domain to be around this value - for example 18km (or 21km) and then use nested domains to go down to 2km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;18km&gt;6km&gt;2km&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or i can start directly with parent domain size 2km?&#xA;What will be the effect of this big gap 20km to 2km? &#xA;Do i need a longer spinup so i can resolve clouds for example, if i choose to start straight with 2km resolution?&#xA;Am i going to miss some kinetic energy from the coarse meteorological input because of dissipation not represented properly?&#xA;I suppose computation time is not much more if i use 18&gt;6&gt;2km compared to starting directly with 2km. From my experience with WRF, finer domains take most of the time to be computed -ar. 85% in my specific setup.&lt;/p&gt;&#xA;" OwnerUserId="8481" LastActivityDate="2017-07-15T01:53:34.537" Title="How to properly setup a domain in NWP model (WRF) according to meteorological input data" Tags="|atmosphere-modelling|weather-forecasting|wrf|nwp|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10736" PostTypeId="2" ParentId="10727" CreationDate="2017-07-03T13:41:30.660" Score="4" Body="&lt;p&gt;The ERA Interim reanalysis is made by ECMWF and the other reanalysis is made by NOAA. Reanalyzes of the past are made by running global climate models and these differ because NOAA and ECMWF use different models and perhaps even slightly different data. The models on the other hand can be very different for example on implementation of data assimilation, parametrization and even grid cell size.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All of these variables are vertically integrated. The ERA variables in the order you mention them contain: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;-Total column water:&lt;/strong&gt; all water&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;-Total column rain water:&lt;/strong&gt; all liquid and solid water in droplets large enough not to be considered cloud droplets (my guess)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;-Total column water vapor:&lt;/strong&gt; all gas phase water&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;-Total column cloud liquid water:&lt;/strong&gt; all liquid cloud water&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The NOAA variables:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;-Cloud water content:&lt;/strong&gt; all liquid and solid cloud water&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;-Precipitable water content&lt;/strong&gt; corresponds to &lt;strong&gt;Total column water&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From these the &lt;strong&gt;Total column water vapor&lt;/strong&gt; corresponds the &lt;strong&gt;Vertically integrated specific moisture&lt;/strong&gt;. None of these is the divergence of the total column water vapor phase that you need. Although the paper you are referring approximates precipitation from moisture divergence, you could use just the &lt;strong&gt;Total column rain water&lt;/strong&gt; and no approximation is needed (I didn't read the paper so I don't know if this is makes sense).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit, added sources:&lt;/strong&gt;&#xA;The ERA variable list can be found &lt;a href=&quot;http://apps.ecmwf.int/codes/grib/param-db&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; and you can search variables there and press them to get the definitions too. For NOAA I couldn't find a source for the definitions of these variables. If someone finds please edit this answer&lt;/p&gt;&#xA;" OwnerUserId="6465" LastEditorUserId="6465" LastEditDate="2017-07-14T06:21:16.903" LastActivityDate="2017-07-14T06:21:16.903" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="10737" PostTypeId="2" ParentId="8716" CreationDate="2017-07-03T13:49:44.657" Score="3" Body="&lt;p&gt;Elevation affects precipitation significantly, especially in a mountain environment. On the windward side of a mountain, precipitation is increased. As air parcel rises due to increasing elevation on the windward side of the mountain, the air parcel cools, condenses, and it rains. Once the air parcel (cloud) moves over the peak of the mountain, the air parcel dries and warms quickly as it flows down the leeward side of the mountain. This is known as adiabatic warming or compressional warming. In the United States and Canada, there are north to south mountain ranges. On the westward side (windward side), it is green and the areas receive plenty of precipitation. On the eastern side, there are more arid conditions. Plateaus (flat areas of high elevation) can also have an affect on precipitation. Thermal lows can form over plateaus in the subtropics (like Mexico or parts of Asia), causing precipitation. This is a form of a summer monsoon. &lt;/p&gt;&#xA;" OwnerUserId="8483" LastActivityDate="2017-07-03T13:49:44.657" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10738" PostTypeId="2" ParentId="10693" CreationDate="2017-07-03T17:09:39.210" Score="1" Body="&lt;p&gt;There is &lt;strong&gt;always&lt;/strong&gt; a background voltage difference from the ground up, of about 100V per vertical meter resulting in a net voltage difference of about 400,000V between the top of the atmosphere and earth ground. However, being a good insulator, makes for lousy conductivity, therefore the current density is extremely low which would make measuring with a common multimeter pretty hard: there's just not enough surface area on those tiny leads over which to contact air and ground. Add to that the very low current density, and your digital multimeter (DMM) is nowhere near sensitive enough to measure that voltage difference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although the moments preceding a lightning strike will generate a potential of tens of millions of volts, using a DMM still leaves you with a few big problems:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Lighting is an energy transmission that channels through a &quot;pipe&quot; of ionized air molecules. You'd be hard pressed to predict where that pipe is going to set up, getting there in time, and most importantly, surviving the instant supernova of steam that your body would turn into.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) You're still left with the problem of the tiny surface area of DMMs leads. Sure, there's a big voltage potential, but the current density is still too small to measure with an unmodified DMM. Like Trond Hansen notes above, you'd need to connect your DMM to a large &quot;collector&quot; to actually see the difference, (then calculate the current density observed based on the surface area of your collector.)&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-07-03T17:09:39.210" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10739" PostTypeId="2" ParentId="10730" CreationDate="2017-07-03T17:36:50.443" Score="1" Body="&lt;p&gt;Your &amp;quot;Inuksuk&amp;quot; is simply a lucky combination of the sun's angle grazing an erosional remnant of the adjacent riverbank. If you go upriver, you'll see the same erosional remnant, now with sunlight at a perpendicular angle....not so mysterious, right?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/e1FGi.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/e1FGi.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Far more curious, to me at least, is why the riverbank has been incised in such a way. I suspect that permafrost riverbanks erode differently than the usual  garden variety riverbanks.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-07-03T17:36:50.443" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10741" PostTypeId="1" AcceptedAnswerId="10747" CreationDate="2017-07-03T21:10:34.267" Score="1" ViewCount="136" Body="&lt;p&gt;Which reflects more UVB from the sun, a flat laying white cloth sheet, or a flat laying aluminum sheet? Ie. Which material would reflect a wavelength of 280 to 315 nm best?&lt;/p&gt;&#xA;" OwnerUserId="8486" LastEditorUserId="39" LastEditDate="2017-07-04T10:42:41.597" LastActivityDate="2017-07-04T19:04:42.323" Title="Relative UVB reflectance of white cloth vs aluminum" Tags="|meteorology|" AnswerCount="1" CommentCount="3" ClosedDate="2017-07-13T22:56:28.570" ContentLicense="CC BY-SA 3.0" />
  <row Id="10742" PostTypeId="1" AcceptedAnswerId="10752" CreationDate="2017-07-03T23:23:11.563" Score="6" ViewCount="535" Body="&lt;p&gt;I am curious of how metal deposits are located in general, but to keep my question focused I wanted to just ask about tantalum for example.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there people who traverse their own country drilling core samples here and there? What indicators would they be looking for tantalum in particular?&lt;/p&gt;&#xA;" OwnerUserId="8487" LastEditorUserId="1149" LastEditDate="2017-07-05T13:29:27.917" LastActivityDate="2017-07-06T15:03:40.197" Title="How are deposits of metals like tantalum located?" Tags="|geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10745" PostTypeId="1" CreationDate="2017-07-04T06:48:46.630" Score="1" ViewCount="435" Body="&lt;p&gt;Assuming in the past the water of the oceans were lower does it also mean that the water was not where it is right now? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If yes, then how do we calculate approximately where the water would have been 300 or 1000 years ago?&lt;/p&gt;&#xA;" OwnerUserId="8489" LastActivityDate="2017-07-04T06:48:46.630" Title="Is there a formula to calculate shoreline length or water position from ocean?" Tags="|climate-change|oceanography|ocean-currents|global-weirding|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10746" PostTypeId="1" AcceptedAnswerId="10748" CreationDate="2017-07-04T18:36:05.300" Score="7" ViewCount="16729" Body="&lt;p&gt;Please explain the main differences between Climatology, Meteorology and Atmospheric Science.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="8495" LastEditorUserId="543" LastEditDate="2017-07-05T01:35:46.453" LastActivityDate="2020-09-17T14:45:39.817" Title="What are the differences between Climatology, Meteorology and Atmospheric Science?" Tags="|meteorology|climatology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10747" PostTypeId="2" ParentId="10741" CreationDate="2017-07-04T19:04:42.323" Score="1" Body="&lt;p&gt;I understand that polished aluminum surface reflects more that white. However , the white surface re-emits more energy  so the net affect is that the white retains less energy. &lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2017-07-04T19:04:42.323" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10748" PostTypeId="2" ParentId="10746" CreationDate="2017-07-04T19:34:22.593" Score="12" Body="&lt;p&gt;Atmospheric science is the generic study of the atmosphere. This includes climatology, air quality, and meteorology. It is often all-encompassing. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Climatology- the study of climate, the atmosphere over an extended period of time. This can usually be seen from either a statistical or physical perspective. Usually, the statistical approach looks at climate extrema. Physical climatology studies the processes that drive climate, and may be used as reconstruction, or prediction. Some of the processes that meteorologists may neglect, such as aerosols and long term trends in oceanography, are very relevant in climatology. Climatology is also a subset of atmospheric science.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meteorology is the study of weather, especially in forecasting. Often, meteorologists interface with the public, via television, forensic meteorology, produce forecasts etc. In regards to research, meteorologists often study improvements to atmospheric models, or other aspects to forecasting. Some research meteorologists study mechanisms behind certain weather phenomena, in order to improve understanding, say of severe weather, atmospheric chemistry, turbulence, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For reference:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Meteorology time scales: Seconds-Weeks&lt;/li&gt;&#xA;&lt;li&gt;Climatology time scales: Months-decades&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In summary:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Atmospheric science is a generic term describing the study of the atmosphere.&lt;/li&gt;&#xA;&lt;li&gt;Meteorology is the study of the atmosphere, generally in the short term. Occupationally, it involves interfacing with the public. Research meteorologists study a vast number of topics.&lt;/li&gt;&#xA;&lt;li&gt;Climatology studies the evolution of the atmosphere over long timescales, including how it may be changing. Some of the things that meteorologists may neglect, climatologists must consider.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-07-04T19:34:22.593" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10751" PostTypeId="2" ParentId="1061" CreationDate="2017-07-06T13:02:37.547" Score="5" Body="&lt;p&gt;I think the commenters have identified the issue. Halite does not have perfect cleavage along the {110} plane. As recorded in &lt;a href=&quot;http://www.webmineral.com/data/Halite.shtml#.WV40FlGQxpg&quot; rel=&quot;noreferrer&quot;&gt;Mindat&lt;/a&gt;, Halite has perfect cleavage alone {100}, {010}, and {001}. This makes sense, as Halite is a cubic mineral (fcc), these are the planes you would expect it to cleave on. &lt;/p&gt;&#xA;" OwnerUserId="8500" LastActivityDate="2017-07-06T13:02:37.547" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10752" PostTypeId="2" ParentId="10742" CreationDate="2017-07-06T15:03:40.197" Score="4" Body="&lt;p&gt;Metal oxide minerals like tantalite (tantalum) and columbite (niobium) often form placer deposits within basins and drainages. The placer deposits are a secondary ore deposits created by the weathering of tantalite/columbite bearing granite and the transport of heavy sands by water and gravity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Based on this information, a good approach to prospecting for tantalum / niobium would be collect dark/black sand samples from stream beds within a granite mountain range and to collect samples from riverbeds flowing out of mountain ranges with exposed granite. Larger rivers with steep terrain can carry heavy sediment further away from its source area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Example: Sawtooth Mountains in Central Idaho are a large granite batholith complex..  Salmon river and its tributaries would excellent areas to look for placer deposits (except of course most of this area is designated as National Forest land.) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AR6Ct.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AR6Ct.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-07-06T15:03:40.197" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10753" PostTypeId="1" AcceptedAnswerId="10756" CreationDate="2017-07-06T18:33:22.873" Score="1" ViewCount="906" Body="&lt;p&gt;What do geologists mean when they say - Cambrian/Precambrian Boundary problems or Cretaceous/Tertiary boundary problems?&lt;/p&gt;&#xA;" OwnerUserId="8159" LastActivityDate="2017-07-07T09:08:52.403" Title="Boundary problems in stratigraphy" Tags="|geology|paleontology|stratigraphy|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10756" PostTypeId="2" ParentId="10753" CreationDate="2017-07-07T09:08:52.403" Score="3" Body="&lt;p&gt;I believe what is being referred to here is the problem of determining where, in a continuous deposition sequence, a particular geologic time transition occurs.  If you have uniform depositional conditions you look for a transition in fossil communities that have been agreed on as marking the transition.  Life is not so simple and you could have a delta sequence overlaying a deep water deposit. Obviously the geologic aeon does not change everywhere at the contact between clay and sandstone and one must determine where in the clay the line is to be drawn and where in the sandstone.  On a larger scale a time boundary that, in the type section, starts or ends at an unconformity needs to be more precisely defined so that correlations across geologic provinces can be made.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2017-07-07T09:08:52.403" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10760" PostTypeId="1" CreationDate="2017-07-07T22:24:13.803" Score="3" ViewCount="223" Body="&lt;p&gt;I wish I had a picture of this thing I saw, and I did try to video it, but then they hurtled very quickly out of sight. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyway, I will try to explain. . . &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You know when you're up in a plane in the sky, you can see clouds in 'individual' balls? Well, it was about to rain yesterday and the sky was dark. Then suddenly I could see something like a very big, dirty, semi-transparent ball of cotton wool-like cloud hurtling towards me and over my roof. Then another, and then another. By the time I ran outside to try and video them, I could only see one very far off and it was going in a different direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The thing about it was that it wasn't like the entire mass of clouds moving across the sky, but it was like balls of clouds or gas, and they were just stumbling across the sky like they had been detached and blown away. And they were not looking nice or anything, but like a pocket of bad gas or something.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have very little knowledge of science and I wonder if anyone is familiar with and can tell me what I saw?&lt;/p&gt;&#xA;" OwnerUserId="8517" LastActivityDate="2017-07-09T10:05:35.090" Title="What could the ball of cloud I saw be?" Tags="|clouds|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10761" PostTypeId="1" AcceptedAnswerId="10764" CreationDate="2017-07-08T01:54:30.080" Score="10" ViewCount="423" Body="&lt;p&gt;The Wikipedia article on the subject of the &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Antarctic_ice_sheet&quot; rel=&quot;noreferrer&quot;&gt;Antarctic ice sheet&lt;/a&gt;&quot; says that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The icing of Antarctica began in the middle Eocene about 45.5 million&#xA;  years ago and escalated during the Eocene–Oligocene extinction event&#xA;  about 34 million years ago.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The article later says that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Ice enters the sheet through precipitation as snow. This snow is then&#xA;  compacted to form glacier ice which moves under gravity towards the&#xA;  coast.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However it looks like, from the photos of Antarctica, that this transfer of ice to the coasts is not happening everywhere on Antarctica. Rather, many places seem to be under a perpetual ancient ice cover.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the precipitation was recycled at a continuous rate everywhere, it shouldn't be possible to obtain a 1.5 million year old core sample (according to an article in Nature) or structures such as Vostok Station that covers an ancient lake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A similar location is &lt;a href=&quot;https://en.wikipedia.org/wiki/Dome_F&quot; rel=&quot;noreferrer&quot;&gt;Dome F&lt;/a&gt; that according to Wikipedia has a yearly precipitation of about 25 mm (millimeters; approx. 0.98 inches).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the question is, if we have a 25 mm precipitation per year for even just 10 million years, we should have an ice cover that's 250 kilometers thick. Or if we had it during just a 5 million year time span, it should give us an ice cover that's 125 kilometers thick.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reasonably we could allow for some compression of the ice but still keeping in mind that we are not talking about a neutron star here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How come the current Antarctic ice cover is just a couple of miles thick?&lt;/p&gt;&#xA;" OwnerUserId="8518" LastEditorUserId="2470" LastEditDate="2021-07-06T06:59:38.773" LastActivityDate="2021-07-06T06:59:38.773" Title="Considering how old the Antarctic ice cover is, why isn't it much thicker?" Tags="|glaciology|ice-sheets|antarctica|" AnswerCount="4" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10762" PostTypeId="1" AcceptedAnswerId="10765" CreationDate="2017-07-08T06:43:55.383" Score="4" ViewCount="651" Body="&lt;p&gt;Why is the surface waters in the Northwest Atlantic Ocean colder than the surface waters of the Northeast Atlantic Ocean? &lt;/p&gt;&#xA;" OwnerUserId="8522" LastEditorUserId="2536" LastEditDate="2017-07-08T11:21:32.473" LastActivityDate="2017-07-08T11:43:06.883" Title="Difference in surface temperature between the Northwest Atlantic and Northeast Atlantic" Tags="|ocean|oceanography|temperature|ocean-currents|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10763" PostTypeId="1" CreationDate="2017-07-08T06:44:34.573" Score="2" ViewCount="88" Body="&lt;p&gt;In chapter 3 of &quot;The Revolutions of the Heavenly Spheres&quot; where Copernicus defines &quot;how the Earth forms a single sphere with water&quot;, the Edward Rosen translation of the book states this.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;For they do not realize that the water cannot be even seven times greater and still leave any part of the land dry, unless earth as a whole vacated the center of gravity and yielded that position to water, as if the latter were heavier than itself For, spheres are to each other as the cubes of their diameters. Therefore, if Earth were the eighth part to seven parts of water, earth's diameter could not be greater than the distance from [their joint] center to the circumference of the waters.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;For context, &quot;they&quot; is referring to Aristotelians which according to Copernicus, believe that there is ten times more water than land.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My main lack of understanding comes from how Copernicus uses the statement &quot;spheres are to each other as the cubes of their diameters.&quot; To prove that &quot;if Earth were the eighth part to seven parts of water, earth's diameter could not be greater than the distance from [their joint] center to the circumference of the waters.&quot; Thereby showing that a 1:7 ratio of land to water is the threshold where water submerges the entire Earth.&lt;/p&gt;&#xA;" OwnerUserId="8523" LastEditorUserId="6467" LastEditDate="2017-07-09T07:42:13.717" LastActivityDate="2017-07-09T07:42:13.717" Title="How Copernicus figured out that it took 7 parts of water and 1 part earth until the entire Earth was submersed in water" Tags="|history-of-science|" AnswerCount="0" CommentCount="2" ClosedDate="2017-07-10T01:30:25.220" ContentLicense="CC BY-SA 3.0" />
  <row Id="10764" PostTypeId="2" ParentId="10761" CreationDate="2017-07-08T11:18:33.187" Score="9" Body="&lt;p&gt;Ice floats with gravity towards lower elevation, the flow continues until the base of the ice sheet becomes floating and the ice forms an ice shelf or icebergs. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Due to the subglacial topography, basal melting and mass balance, the flow velocities vary over a large range, faster outflows are glaciers. The pattern is somehow similar to how rivers transport rainwater towards the coasts. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The thickness of the ice sheet is controlled by a complex relation between &lt;a href=&quot;https://en.wikipedia.org/wiki/Accumulation_zone&quot; rel=&quot;noreferrer&quot;&gt;accumulation&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Ablation_zone&quot; rel=&quot;noreferrer&quot;&gt;ablation&lt;/a&gt; and compaction.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mC9rd.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mC9rd.jpg&quot; alt=&quot;Flow velocities MEaSUREs, plotted from Quantarctica&quot;&gt;&lt;/a&gt;&#xA;&lt;em&gt;Flow velocities from &lt;a href=&quot;https://nsidc.org/data/docs/measures/nsidc0484_rignot/&quot; rel=&quot;noreferrer&quot;&gt;MEaSUREs&lt;/a&gt; (NASA), plotted from &lt;a href=&quot;http://quantarctica.npolar.no/&quot; rel=&quot;noreferrer&quot;&gt;Quantarctica&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ice velocity map shows, that some areas are unaffected by the flow towards the coast. Some of these areas are ice-free. Also at some inland locations, as Vostok, the velocity is very slow. Also, note that this is the surface velocity. At the base, the ice flows slower or not at all. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To investigate the mass balance further, I recommended you to download &lt;a href=&quot;http://quantarctica.npolar.no/&quot; rel=&quot;noreferrer&quot;&gt;Quantarctica&lt;/a&gt; and look closer at the datasets. &lt;a href=&quot;https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/20140006608.pdf&quot; rel=&quot;noreferrer&quot;&gt;Shepherd et al (2012)&lt;/a&gt; is a good first read about the methods used to estimate changes in ice mass and the present changes. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastActivityDate="2017-07-08T11:18:33.187" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10765" PostTypeId="2" ParentId="10762" CreationDate="2017-07-08T11:43:06.883" Score="5" Body="&lt;p&gt;The main reason is that the &lt;a href=&quot;https://www.livescience.com/26273-gulf-stream.html&quot; rel=&quot;noreferrer&quot;&gt;Gulf Stream&lt;/a&gt; transports warm surface water from the tropics, driven by the thermohaline circulation. The tropical &lt;a href=&quot;https://en.wikipedia.org/wiki/Trade_winds&quot; rel=&quot;noreferrer&quot;&gt;trade winds&lt;/a&gt; push surface water towards Western Atlantic and build up stress. Further north the dominant wind direction is towards the east. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Coriolis_force&quot; rel=&quot;noreferrer&quot;&gt;Coriolois force&lt;/a&gt; also helps to move the warm water masses towards the east.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Labrador_Current&quot; rel=&quot;noreferrer&quot;&gt;Labrador Current&lt;/a&gt;, on the other hand, brings cold water down West Atlantic Ocean. The thermohaline turnover is further south in West Atlantic Ocean. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UYeRb.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UYeRb.jpg&quot; alt=&quot;Wikipedia RetAndr data from http://www.ngdc.noaa.gov/mgg/image/2minrelief.html&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2536" LastActivityDate="2017-07-08T11:43:06.883" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10766" PostTypeId="1" CreationDate="2017-07-08T16:54:01.507" Score="7" ViewCount="584" Body="&lt;p&gt;I would like to know how the core is cut off at the bottom of the drill. I also would like to know how the core is brought up to the surface without slipping out and falling back down.&lt;/p&gt;&#xA;" OwnerUserId="9524" LastActivityDate="2018-05-10T20:35:30.590" Title="In the oil field, when a vertical cylinder coring sample is taken, how is the core severed at the bottom and removed from the formation?" Tags="|geology|geophysics|petroleum|geoengineering|" AnswerCount="4" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10767" PostTypeId="2" ParentId="10760" CreationDate="2017-07-08T19:41:14.213" Score="3" Body="&lt;p&gt;It's hard to visualize exactly what you saw, but typically in &lt;a href=&quot;http://www.met.tamu.edu/class/atmo202/Exer10dir/convectiveclouds.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;convective clouds&lt;/a&gt;, there is such significant motion that oftentimes very chaotic and varying cloud shapes will develop as a result, and they may move quite quickly due to the strong winds.  It appears the term &lt;a href=&quot;http://www.cloudgallery.mpich.de/Stratus/St_fractus_pannus/st_fracpan_new.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;pannus&lt;/a&gt; may be used for these, though I'm more familiar with calling them &lt;a href=&quot;https://en.wikipedia.org/wiki/Scud_(cloud)&quot; rel=&quot;nofollow noreferrer&quot;&gt;scud&lt;/a&gt;.  You mentioned rain, it's northern hemisphere summer, so these cumulus-convection byproducts sounds quite likely.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Around other storm chasers/meteorologists, I've also heard these types of clouds called debris clouds... which is a rather apropos description given that such clouds are often leftovers from earlier storm evolution (perhaps even remnants of old wall clouds if in a situation with supercells)... but using that term might bring confusion to others because tornado debris can also be called a &lt;a href=&quot;http://forecast.weather.gov/glossary.php?word=debris%20cloud&quot; rel=&quot;nofollow noreferrer&quot;&gt;debris cloud&lt;/a&gt;.  &lt;a href=&quot;http://namesofclouds.com/types-of-clouds/debris-clouds.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;This page appears&lt;/a&gt; to exemplify the confusion, as the picture appears to include remnant clouds from earlier storms in the foreground while the description gives the tornadic definition.  So we probably should avoid this term.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's no bad gas in thunderstorms... what you see in meteorological clouds is liquid or ice water (all clouds form around &lt;a href=&quot;https://www.google.com/search?q=cloud%20condensation%20nuclei&amp;amp;ie=utf-8&amp;amp;oe=utf-8&quot; rel=&quot;nofollow noreferrer&quot;&gt;tiny bits of dust and such&lt;/a&gt;, but this wouldn't affect appearance).  Occasionally smoke or such may be ingested in a cloud, but even in situations where large &lt;a href=&quot;https://en.wikipedia.org/wiki/Flammagenitus_(cloud)&quot; rel=&quot;nofollow noreferrer&quot;&gt;fires and volcanic eruptions&lt;/a&gt; produce clouds, the forced moist updraft region will often &lt;a href=&quot;https://www.youtube.com/watch?v=UDAVuOt9u30&quot; rel=&quot;nofollow noreferrer&quot;&gt;look quite similar&lt;/a&gt; to a typical cumulus cloud.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2017-07-08T19:41:14.213" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10768" PostTypeId="2" ParentId="10766" CreationDate="2017-07-08T22:22:45.040" Score="0" Body="&lt;p&gt;I doubt this technique is used in petroleum, the wells are usually too deep for this to be practical. It is used for mineral deposits that are not so deep : As I remember &quot;Longear&quot; makes these coring tubulars. I expect the core rock breaks at natural fissures. Petroleum formations are evaluated by examining the drillings in the drilling mud. &lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2017-07-08T22:22:45.040" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10769" PostTypeId="1" CreationDate="2017-07-08T23:42:31.397" Score="3" ViewCount="56" Body="&lt;p&gt;I am considering a MS in Geoscience but am curious with the naming conventions associated within the fields of geology. Is Geoscience similar, or interchangeable with geology? Yes, I would be new to the field. I would like to couple my aviation (meteorology, etc.) schooling with a science-rich program. Everyone appears to be professionals on here and would likely know the answer.&lt;/p&gt;&#xA;" OwnerUserId="9526" LastEditorUserId="725" LastEditDate="2017-07-09T07:02:15.060" LastActivityDate="2023-06-19T07:35:45.660" Title="MS in Geosciences With Concentration in Environmental Geosciences Degree Outlook" Tags="|geology|terminology|education|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10770" PostTypeId="1" AcceptedAnswerId="10779" CreationDate="2017-07-08T23:52:45.387" Score="3" ViewCount="166" Body="&lt;p&gt;If we did a thought experiment and imagined the Earth to be covered in a global ocean (ie. no land to slow winds or direct ocean currents) would winds and waves be perpetually enormous or would they come to some sort of equilibrium state?&lt;/p&gt;&#xA;" OwnerUserId="4600" LastActivityDate="2017-07-17T20:04:49.610" Title="Land's effect on winds and currents?" Tags="|ocean-currents|air-currents|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10771" PostTypeId="2" ParentId="10769" CreationDate="2017-07-09T07:05:58.393" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is Geoscience similar, or interchangeable with geology?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Geology is, strictly speaking, a subset of the wider field of geosciences. However, this probably doesn't mean much when people look at the name of your degree or the name of the department of school that awarded your degree. As farrenthorpe said in the comments, what's important is what you do in your research.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Common names for degrees (or departments) could be geoscience, geology, earth science (like the place when I am at the moment), earth and marine science, geological and environmental science (like the place where I did my BSc and MSc at). Doesn't matter. You are probably looking for something in the general field of atmospheric sciences, and each of variations above may or may not include it. Find schools that you're interested in and check each case on its own.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-07-09T07:05:58.393" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10772" PostTypeId="2" ParentId="5044" CreationDate="2017-07-09T08:43:17.557" Score="0" Body="&lt;p&gt;Outside the rain area, it may be sunny and a cloud may look very dark in comparison to the sun-lit background. Once the cloud moves overhead and rain begins, the  eyes adapt to the reduced illumination --- the pupils enlarge --- so it seems less dark. This may not be the only reason why clouds can look darker before it rains, but it is one of the reasons.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-07-09T08:43:17.557" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10773" PostTypeId="1" CreationDate="2017-07-09T09:06:07.937" Score="0" ViewCount="93" Body="&lt;p&gt;If an asteroid strikes a glacier, does it make a print on the land below? For example, a 10 km wide asteroid on a 2 km thick glacier, or a 2 km wide asteroid on a 2 km thick glacier.&lt;/p&gt;&#xA;" OwnerUserId="9527" LastEditorUserId="11908" LastEditDate="2019-03-13T05:05:59.327" LastActivityDate="2019-03-13T05:05:59.327" Title="If an asteroid strikes a glacier, does it make a print on the land below?" Tags="|geology|glaciology|impacts|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10774" PostTypeId="2" ParentId="10760" CreationDate="2017-07-09T10:05:35.090" Score="0" Body="&lt;p&gt;I'm sorry, I'm going to respond to you here because I don't want to go and join the forum to be able to comment. Like I said earlier, I'm not a science-minded person and I was just looking for a quick once-off help here among you esteemed science people.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Well, I've gone through your detailed and impressive answer (thanks a lot), but most of it just went over my head! So I simply followed your links to study the pictures and I think &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:A_cloud_of_dust_and_debris_rises_into_the_air_above_the_Ladar_bazaar_after_U.S._Marines_detonated_a_line_charge_in_Shukvani,_Helmand_province,_Afghanistan,_Aug_110805-M-VI276-097.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one I found on this site of a debris cloud&lt;/a&gt; came closest to what I saw--only it was just like this really tiny chunks of this thing called a debris cloud.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Well, the thing that 'impressed' me was how the cloud was just hurtling across like a cotton ball that was being blown by someone's mouth. And I did worry if it's some kind of pollution emission as I live close to an industrial estate.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gAQNf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gAQNf.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="9528" LastActivityDate="2017-07-09T10:05:35.090" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10775" PostTypeId="1" CreationDate="2017-07-09T10:48:28.027" Score="4" ViewCount="133" Body="&lt;p&gt;Recently I was reading &lt;a href=&quot;http://press.princeton.edu/titles/9691.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;'How to build a habitable planet'&lt;/a&gt; by Langmuir and Broecker and in chapter 15 they speak about how Life has led to a difference in oxidation potential in the atmosphere, essentially leading to the earth becoming a fuel cell. They also spoke about how this led to certain ions being oxidized - ie uraninite to uranyl oxide, iron to hematite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was wondering if this could mean that as atmospheric composition would affect the sea floor, when this subducted it would affect the melt of the mantle - as far as I'm aware, it is the dehydration of the subducting slab which allows for the hydration, and therefore melt, of the mantle in regions such as Japan. If the subducting slab's composition is affected by the atmosphere, could this have any effect on the composition of the igneous rocks formed? Would this be detectable?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="9529" LastEditorUserId="2536" LastEditDate="2017-07-09T11:26:23.517" LastActivityDate="2017-07-10T14:52:12.507" Title="Can the atmosphere affect the composition of igneous rocks?" Tags="|atmosphere|igneous|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10776" PostTypeId="2" ParentId="10773" CreationDate="2017-07-09T12:45:13.437" Score="4" Body="&lt;p&gt;A 10 km asteroid would not only obliterate the section of glacier it hit, but also create a huge crater at the impact site!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The asteroid that created the &lt;a href=&quot;https://en.wikipedia.org/wiki/Vredefort_crater&quot; rel=&quot;nofollow noreferrer&quot;&gt;Vredefort crater&lt;/a&gt; in South Africa is estimated to have been 10 to 15 km in diameter. It is also estimated that the initial crater created by the impact, some 2 billion years ago before it was eroded, was 300 km in diameter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To date, this is the largest recognized asteroid crater on Earth. The crater that was produced by the dinosaur extinction asteroid, in the Yucatan (&lt;a href=&quot;https://en.wikipedia.org/wiki/Chicxulub_crater&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chicxulub&lt;/a&gt;) was only 180 km in diameter. Interestingly, the asteroid that created that crater was also estimated to be 10 to 15 km in diameter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://www.infobarrel.com/Two_Awesome_Meteorite_Craters_in_Australia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gosses Bluff Crater&lt;/a&gt;, in Australia, is 22 km in diameter and it is estimated to have been created by an asteroid 1 km in diameter. The rim of the crater is still 150 m above the surrounding desert.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any sizable asteroid will vaporize the section of glacier it hits and create a large crater at the impact site.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-07-09T12:45:13.437" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10777" PostTypeId="1" CreationDate="2017-07-09T16:01:20.557" Score="2" ViewCount="291" Body="&lt;p&gt;Most meteoroids burn up in the atmosphere, so they don't impact the Earth's surface.  Factors that seem important include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;size and mass of the meteoroid&lt;/li&gt;&#xA;&lt;li&gt;angle of meteoroid's path through the atmosphere&lt;/li&gt;&#xA;&lt;li&gt;latitude where meteoroid enters Earth's atmosphere&lt;/li&gt;&#xA;&lt;li&gt;speed of meteoroid relative to Earth's movement&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Are there other factors that are needed to calculate if a meteoroid will burn up in the atmosphere?  How do we calculate if a meteoroid will completely burn up in the atmosphere?  &lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-07-10T12:32:02.173" Title="How do we calculate if a meteoroid will completely burn up in the atmosphere?" Tags="|atmosphere|astronomy|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10778" PostTypeId="2" ParentId="10777" CreationDate="2017-07-10T02:58:29.307" Score="1" Body="&lt;p&gt;In order to calculate when and how quickly burnup happens, one needs to understand the process of burnup first.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When an object from space enters an atmosphere, this happens at orbital speeds, which at the rest-frame of the atmosphere corresponds to very high mach-numbers. For the space-shuttle this was around 30 and is more or less the lowest attainable &lt;a href=&quot;https://en.wikipedia.org/wiki/Mach_number&quot; rel=&quot;nofollow noreferrer&quot;&gt;mach number&lt;/a&gt; coming from low earth orbit (LEO). &#xA;If one takes a look at the Mach numbers that meteoroids achieve (as you correctly stated, that depends on the latitude, and day/night) i.e. the published numbers from the &lt;a href=&quot;http://www.astro.uu.se/~meteor/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Swedish fireball network&lt;/a&gt; the Mach numbers can reach and surpass ~100. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm mentioning the Mach number, because the shock heating that results from the supersonic atmospheric entry is a strong function of it. As soon as it gets hot inside of the shock, where the meteoroid is sitting (several thousand K) the rock is evaporating into the atmosphere. That's a process that is well understood, and the main uncertainties are the Mach numbers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Break-up can occur during atmospheric entry, as the turbulent fluctuations around the shock are very strong and can cause the meteoroid material to rupture. This is strongly depending on what the meteoroid is made of (think how an icy meteoroid will rupture much more easily than one made of pure iron) and is thus intrinsically unknown.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;After breakup the surface area of the fragments is much higher than before, which causes evaporation to go much quicker, and the same process as above starts over again, until the meteoroid evaporates completely or crashes into the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, we cannot reliably predict of a meteoroid will burn up or not.&#xA;However guesstimates are possible based on the size of the object.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2017-07-10T02:58:29.307" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10779" PostTypeId="2" ParentId="10770" CreationDate="2017-07-10T07:29:04.777" Score="4" Body="&lt;p&gt;They would come to equilibrium, or rather steady state, at which energy input ultimately from the Sun matches energy dissipation by friction. The wind speeds would be somewhat higher because water presents less friction than land, but not higher by a huge factor. This state of affairs exists to a good approximation in the prevailing westerlies of the Southern Hemisphere --- the Roaring 40s.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-07-10T07:29:04.777" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10780" PostTypeId="2" ParentId="10777" CreationDate="2017-07-10T12:32:02.173" Score="2" Body="&lt;p&gt;The density &amp;amp; &lt;a href=&quot;http://www.pibburns.com/catastro/meteors.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;composition of the meteoroid&lt;/a&gt; would be important.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are three main &lt;a href=&quot;http://geology.com/meteorites/meteorite-types-and-classification.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;types of meteoroids&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Iron&lt;/li&gt;&#xA;&lt;li&gt;Stone, &amp;amp;&lt;/li&gt;&#xA;&lt;li&gt;Iron-Stone&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Iron meteoroids are dense &amp;amp; would be somewhat resistant to burning up. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Stone meteoroids are composed of grains of material. The composition of these meteoroids is 75-90 percent silicates. They tend to resemble terrestrial rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Iron-stone meteoroids contain approximately equal amount of iron and stone material.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another factor to consider is the shape of the meteoroid. A meteoroid that is rounded will have better streamlining properties that a meteoroid that is more angular or elongated in shape. Being more streamlined, less of the meteoroid will be exposed to burning air as it travels through the air at high speed. Also, the more streamlined the meteoroid the more likely one aspect will be exposed to high heating than a meteoroid that is more angular and rotating/tumbling as it travels through the air.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-07-10T12:32:02.173" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10781" PostTypeId="2" ParentId="10775" CreationDate="2017-07-10T14:52:12.507" Score="1" Body="&lt;p&gt;I figure you're looking for more exotic examples, and some geologists may well have some offhand, but I want to say &quot;yes&quot; because of the example of carbonatite rocks described in this &lt;a href=&quot;http://www.geology.sdsu.edu/how_volcanoes_work/Unusual%20lava.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;geology page from San Diego State University&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Carbonatites are perhaps the most unusual of all lavas. They are&#xA;  defined, when crystalline, by having more than 50% carbonate&#xA;  (CO3-bearing) minerals, and typically they are composed of less than&#xA;  10% SiO2.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Which would rely on the carbon cycle and the deposition of atmospheric CO2 onto the seafloor by biological processes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Some scientists believe that the Ca-carbonatites are generated by&#xA;  fractional melting of crustal carbonate rocks. However, others believe&#xA;  that the Ca-carbonatites are not primary magmas at all, but rather&#xA;  derived from the alteration of Na-rich natrocarbonatite lavas.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There is an interesting paper in GeoScienceWorld titled &lt;a href=&quot;http://geology.geoscienceworld.org/content/45/4/379&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atmospheric K-feldspar as a potential climate modulating agent through geologic time&lt;/a&gt; that addresses your topic as the author tries to estimate K-feldspar (Kfs) flux through geologic time -- which addresses your question from the other direction: assessing atmospheric content (in some cases simple dust deposition) over billions of years by evaluating its traces in the geological record.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2017-07-10T14:52:12.507" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10782" PostTypeId="1" CreationDate="2017-07-10T15:48:57.717" Score="2" ViewCount="1344" Body="&lt;p&gt;Looking at this GFS &lt;a href=&quot;http://nomads.ncep.noaa.gov:9090/dods/gfs_0p50/gfs20170707/gfs_0p50_12z.ascii?tmax2m[0:2][124:128][279:283]&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://nomads.ncep.noaa.gov:9090/dods/gfs_0p50/gfs20170707/gfs_0p50_12z.ascii?tmax2m[0:2][124:128][279:283]&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The range defined by the second and third set of brackets specify the grid coordinates, however I'm not sure how to convert between what NOAA is using and the common geographic coordinate system. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would the NOAA equivalent be for this coordinate pair: (36.25, -78.75)?&lt;/p&gt;&#xA;" OwnerUserId="9533" LastEditorUserId="543" LastEditDate="2017-07-10T16:36:21.507" LastActivityDate="2019-07-16T06:14:24.020" Title="How do I convert a latitude/longitude coordinate to a NOAA GFS grid cell location?" Tags="|weather-forecasting|gfs|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10783" PostTypeId="1" AcceptedAnswerId="10785" CreationDate="2017-07-10T17:24:31.017" Score="9" ViewCount="1979" Body="&lt;p&gt;Could this study &quot;totally dismantle&quot; Global Warming claims?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's the assertion made in the article &lt;a href=&quot;http://www.theblaze.com/news/2017/07/09/bombshell-climate-change-study-could-totally-dismantle-the-claim-humans-are-causing-global-warming/&quot; rel=&quot;noreferrer&quot;&gt;‘Bombshell’ climate-change study could totally dismantle the claim humans are causing global warming&lt;/a&gt;.  Quoting from the study:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;The conclusive findings of this research are that the three GAST data&#xA;  sets are not a valid representation of reality,” the authors wrote.&#xA;  “In fact, the magnitude of their historical data adjustments, that&#xA;  removed their cyclical temperature patterns, are totally inconsistent&#xA;  with published and credible U.S. and other temperature data. Thus, it&#xA;  is impossible to conclude from the three published GAST data sets that&#xA;  recent years have been the warmest ever — despite current claims of&#xA;  record setting warming.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;On reading that article I noticed that they name but do not link to the article nor it's publisher. I was able to find it here: &lt;a href=&quot;https://thsresearch.files.wordpress.com/2017/05/ef-gast-data-research-report-062717.pdf&quot; rel=&quot;noreferrer&quot;&gt;On the Validity of NOAA, NASA and Hadley CRU Global Average Surface Temperature Data &amp;amp; The Validity of EPA’s CO2 Endangerment Finding&lt;/a&gt; (pdf), but that's on a Wordpress site, not a credible scientific journal, as far as I can tell.  Further googling only turned up more references in political-influence sources like TheBlaze.com.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The one place that may be presenting as something that they published is the Heartland Institute (&lt;a href=&quot;https://www.heartland.org/publications-resources/publications/on-the-validity-of-noaa-nasa-and-hadley-cru-global-average-surface-temperature-data--the-validity-of-epas-co2-endangerment-finding&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;), but I cannot tell if they are legit or not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is no publication information in the paper itself, nor any evidence of formal &quot;peer-review&quot; other than the list of scientists(?) on page 2 who affirm that they agree with the conclusions (which is not my understanding of what peer-review means nor of how it works).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also have some trouble following the reasoning of their findings and conclusions, which seems like a bit of a logical leap.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, my questions are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Is this a legitimate peer-reviewed scientific paper as they claimed&lt;/li&gt;&#xA;&lt;li&gt;How legitimate/credible is their methodology?&lt;/li&gt;&#xA;&lt;li&gt;How legitimate/credible are their findings?  And is this really something new?&lt;/li&gt;&#xA;&lt;li&gt;Is it published anywhere, and has there been any open scientific review, critique or commentary of it?&lt;/li&gt;&#xA;&lt;li&gt;Does this paper really represent a credible threat to current climate change theories?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="842" LastEditorUserId="9539" LastEditDate="2017-07-11T20:58:14.023" LastActivityDate="2017-07-13T20:01:28.913" Title="Could this study &quot;totally dismantle&quot; Global Warming claims?" Tags="|climate-change|temperature|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10784" PostTypeId="1" CreationDate="2017-07-10T18:15:25.857" Score="4" ViewCount="456" Body="&lt;p&gt;Why is dissolved inorganic phosphorus called soluble reactive phosphorus (SRP) instead of dissolved inorganic phosphorus (DIP)? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seems to me that DIP would be much more clear.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See e.g. &lt;a href=&quot;http://bcn.boulder.co.us/basin/data/NEW/info/TP.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;General Information on Phosphorus&lt;/a&gt; (City of Boulder/USGS Water Quality Monitoring)&lt;/p&gt;&#xA;" OwnerUserId="9534" LastEditorUserId="595" LastEditDate="2017-07-10T19:40:11.550" LastActivityDate="2018-02-14T09:34:37.127" Title="Soluble reactive phosphorus or Dissolved Inorganic Phosphorus?" Tags="|water|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10785" PostTypeId="2" ParentId="10783" CreationDate="2017-07-10T19:26:41.573" Score="16" Body="&lt;p&gt;There is several credibility problems with this work.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;First&lt;/strong&gt;, they mention after the title: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Abridged Research Report&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;but I cannot find any related full work from the authors on the matter. As a comparison, in this case, a short, &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2011EO090001/abstract&quot; rel=&quot;noreferrer&quot;&gt;simplified article&lt;/a&gt; was prepared as a companion for &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2010JG001507/abstract&quot; rel=&quot;noreferrer&quot;&gt;a full paper&lt;/a&gt;. The former is useful for news agencies and general public, and the latter for interested peers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Second&lt;/strong&gt;, references are poor. Data sources are cited, from government or agencies FTP sites, which is probably legit (I did not verify the linked data in great detail). GAST dataset are publicly available, as the freedom to publish possible misinterpretation in a proper peer reviewed journal, which remain to be done for the authors actual work.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Third&lt;/strong&gt;, there is no real methodology. The abridged paper is presenting results and interpretations, but there is no real method.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Fourth&lt;/strong&gt;, p17&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Clearly the historical GAST data adjustments that have been made have been dramatic and invariably have been favorable to Climate Alarmists’ views regarding Global Warming&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This type of statement is having no place in a scientific paper, as this is poorly opinionated based on nothing of substance (&lt;em&gt;Clearly&lt;/em&gt;, &lt;em&gt;dramatic&lt;/em&gt;, &lt;em&gt;Climate Alarmist&lt;/em&gt;) and does not prove much, except that the contribution is not scientific.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Fifth&lt;/strong&gt; of less importance. the formatting is very poor, which is not helping with the credibility of authors - not that it is very hard to prepare nice and efficient looking reports these days. In a few words, poor communication (in this case, this paper) is not helpful to convince colleagues of alternative ideas (or any ideas).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Sixth&lt;/strong&gt; until this work reach the stage of being published by an independent peer reviewed medium, I don't see how this could even begin to be a 'threat' to current climate science.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2017-07-10T19:26:41.573" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10786" PostTypeId="1" AcceptedAnswerId="10789" CreationDate="2017-07-10T19:54:29.740" Score="4" ViewCount="251" Body="&lt;p&gt;In a book on invertebrate paleontology I have (Treatise on Invertebrate Palaeontology, A) there is a diagram showing possible fates of a shell after the death of the organism. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the possible fates is &quot;true fossilization&quot;. Another is &quot;impression and pseudomorphism&quot;. What's the difference between these two?&lt;/p&gt;&#xA;" OwnerUserId="9535" LastEditorUserId="2536" LastEditDate="2017-07-10T23:41:53.610" LastActivityDate="2017-07-12T14:38:00.507" Title="&quot;Impression and pseudomorphism&quot; in fossils" Tags="|geology|terminology|fossils|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10787" PostTypeId="1" AcceptedAnswerId="10791" CreationDate="2017-07-10T21:53:14.367" Score="2" ViewCount="1944" Body="&lt;p&gt;Is it possible to locate potential gold deposits using maps that describe dominant rock type, altitude, vegetation, or geological formations?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(I realize that the location would probably still have to be verified by traveling to the actual site. I am only looking for information that serves as an indicator of potential gold reserves.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the sake of this question I am assuming of course that these maps would not directly list gold deposits or existing or past gold mining operations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What kind of information would a map need to contain in order to derive an indication of gold deposits from it?&lt;/p&gt;&#xA;" OwnerUserId="9537" LastActivityDate="2017-07-11T05:58:40.297" Title="Is it possible to determine where gold might be found based on a map, and if so, how?" Tags="|geology|mineralogy|" AnswerCount="3" CommentCount="2" ClosedDate="2017-07-15T08:08:03.557" ContentLicense="CC BY-SA 3.0" />
  <row Id="10789" PostTypeId="2" ParentId="10786" CreationDate="2017-07-10T22:49:06.360" Score="3" Body="&lt;p&gt;&lt;strong&gt;Impression&lt;/strong&gt; are just that, an impression, an imprint of the fossil but the fossil that created it is gone (or just separate) such as &lt;a href=&quot;https://www.bas.ac.uk/wp-content/uploads/2015/04/by-43-1_cm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; impression of a ammonite.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Pseudomorphism&lt;/strong&gt; is just a new term for a natural casting it can be a cast of the fossil or a cast of the fossils impression, again the shape is preserved the the original fossil is seperate or has dissolved and been replaced, for instance the natural casting of the braincase of hominids can be used to reconstruct missing parts of the skull. This &lt;a href=&quot;https://s-media-cache-ak0.pinimg.com/originals/ff/db/a8/ffdba83c45d383067abd78aae078cd67.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;snail&lt;/a&gt; shell is also a pseudomorph, the entire thing has been replaced with agate.&lt;/p&gt;&#xA;&lt;p&gt;In &lt;strong&gt;true fossilization&lt;/strong&gt; some component of the original material is still present this can preserve internal structure. With bone for instance a ture fossil of a bone often has some of the original calcium/phosphate with pore spaces around it filled in with other minerals.  Of course like anything in nature pseudomorph and true fossil are not completely discrete but ends on a spectrum, partial replacement is the norm.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-07-12T14:38:00.507" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10790" PostTypeId="2" ParentId="10766" CreationDate="2017-07-11T00:27:27.563" Score="5" Body="&lt;p&gt;Coring is an important method to get detailed information about the formations, however, it's very time-consuming and costive, so it's only applied when geologists and reservoir engineers need high-resolution data. It is more common in ore prospecting and mining, mapping for infrastructure and basic geological understanding of the 3-dimentional structures. Lake sediment cores are used for &lt;a href=&quot;https://en.wikipedia.org/wiki/Varve&quot; rel=&quot;noreferrer&quot;&gt;varve chronology&lt;/a&gt;. Marine sediments are cored to understand the oceanographic development, date events as slope processes and changes in glaciation and climate. &lt;a href=&quot;http://www.antarcticglaciers.org/glaciers-and-climate/ice-cores/ice-core-basics/&quot; rel=&quot;noreferrer&quot;&gt;Ice is cored&lt;/a&gt; to measure variations in the atmosphere to understand past climate and vulcanism. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To sum up, coring is a very important tool for geologists, not only in oil fields. Cheaper, and faster, alternatives to coring is &lt;a href=&quot;http://petrowiki.org/Mud_logging&quot; rel=&quot;noreferrer&quot;&gt;mud logging&lt;/a&gt;, a very common practise when drilling in oil fields. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;So how to get the cores up from the borehole?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are some different systems used, depending on the rock/sediment and investment involved. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For deep drillings in hard formations, a &lt;em&gt;&lt;a href=&quot;https://www.researchgate.net/profile/Pavel_Talalay/publication/259099023/figure/fig14/AS:287278490107921@1445503937288/Fig-23-Split-ring-core-lifters-for-conventional-prospecting-drilling-Source.png&quot; rel=&quot;noreferrer&quot;&gt;core catcher&lt;/a&gt;&lt;/em&gt; is used in a two-barrel system. The corehead (the drill bit) is connected to the outer barrel, while the core is pushed into an inner barrel. The lower part of the inner barrel is called the &lt;em&gt;shoe&lt;/em&gt; just above the drill. In the shoe, there is a &lt;em&gt;core catcher&lt;/em&gt; that wedges between the barrel and the core. The core catcher is a split ring with a rough inside that holds the core. When you pull the core, it snaps off as the lower and upper shoe squeezes the catcher. The core catcher works somehow like an expansion anchor, but inverted, grabbing the core on the inside of the barrel rather than the wall on the outside. The inner barrel also protects the core from the rotating outer barrel. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For softer sediments, the core catcher is made out of springs that close inwards as the core is pulled. It is sometimes called &lt;em&gt;&lt;a href=&quot;http://image.made-in-china.com/43f34j00SygajEZnApkP/Nq-Basket-Retainer-Core-Spring.jpg&quot; rel=&quot;noreferrer&quot;&gt;basket retainer&lt;/a&gt;&lt;/em&gt; and can be in &lt;a href=&quot;https://www.google.com.au/url?sa=i&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=images&amp;amp;cd=&amp;amp;cad=rja&amp;amp;uact=8&amp;amp;ved=0ahUKEwiPhPjf-v_UAhXLgbwKHdcYAnMQjRwIBw&amp;amp;url=http%3A%2F%2Fgeoprobe.com%2Fsonic-dual-tube-60-sdt60&amp;amp;psig=AFQjCNFq2tBdoz9BoIl9p_rcw5sdcB9acA&amp;amp;ust=1499817861969807&quot; rel=&quot;noreferrer&quot;&gt;metal&lt;/a&gt; or &lt;a href=&quot;https://encrypted-tbn0.gstatic.com/images?q=tbn:ANd9GcT5BkpxDpy6YNJ4CPtMxjavrbqhj2s2u6iUQ3pbOORhGbb7-D6e&quot; rel=&quot;noreferrer&quot;&gt;plastic&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For &lt;a href=&quot;https://www.google.com.au/url?sa=i&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=images&amp;amp;cd=&amp;amp;cad=rja&amp;amp;uact=8&amp;amp;ved=0ahUKEwj7097b-__UAhVINbwKHdGtABsQjRwIBw&amp;amp;url=http%3A%2F%2Fpost.queensu.ca%2F~pearl%2Fcoring%2520instructionsmaxiG.htm&amp;amp;psig=AFQjCNHPp4DQSr_ZhEYINlFQ3qVCZCdq7w&amp;amp;ust=1499819105818932&quot; rel=&quot;noreferrer&quot;&gt;smaller gravity corer&lt;/a&gt;, there is a valve on top of the tube that is closed and the underpressure in the tube holds the core in place. Sometimes... &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Check the linked pictures, they probably explain better how it works, but I couldn't find any good CC.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-07-11T12:28:36.430" LastActivityDate="2017-07-11T12:28:36.430" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10791" PostTypeId="2" ParentId="10787" CreationDate="2017-07-11T03:13:58.377" Score="5" Body="&lt;p&gt;On of the issues with geological maps is they have all required humans to walk over the ground and mark on a piece of paper the surface expressions of different types of rock and geological structures, such as faults and folds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because of this process and the time constraints placed on people when they mapped the land there will always be some level of detail missing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geological maps will show the different rock types and geological structures on the surface but they may not necessarily show what is at depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geology has advanced to a state where most well trained geologist will know the potential for certain rock types to host certain type of mineral deposits, including gold. However, pinpointing where a gold deposit, or any other mineral deposit is located will always require a human to walk the ground and inspect it in more detail and to take samples and have them analyzed in a laboratory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Initially those samples may be geochemical samples, others will be rock samples and chips taken from the surface or trenches dug into the surface, culminating in drill samples being taken.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To further assist where to look, geophysical testing methods may be used, such a magnetic anomaly testing or ground electrical resistivity testing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is very unlikely that anyone will be able to look at a geological map, and with any degree of certainty say &quot;there is a gold deposit&quot; or &quot;there is a gold deposit that is economic to mine&quot;. More likely, a person will look at a geological map and say something like, &quot;there is a greenstone belt, this may have potential to host a gold deposit, further investigation is needed&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is an adage amongst some geologists that states &quot;gold is where you find it&quot;. There is no altitude preferable for finding gold deposits. It's found in mountains, in deserts, in forests, under salt lakes, even dissolved in the oceans. The oceans contain the largest quantities of gold, but it is uneconomic to extract it from sea water because the concentration are so low.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Biological indicators, such a vegetation may work for some base metals, such as copper, but not necessarily for gold.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, gold can occur as a deposit of just gold, but it can also occur in association with other metals in the form of polymetallic deposits which contain gold, silver, copper, lead or zinc, even uranium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, not all deposits of minerals, gold included, are reserves. To be classified as a reserve and an orebody, a deposit of mineralization must be economic to mine.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="6298" LastEditDate="2017-07-11T05:58:40.297" LastActivityDate="2017-07-11T05:58:40.297" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10792" PostTypeId="2" ParentId="10787" CreationDate="2017-07-11T04:02:32.033" Score="4" Body="&lt;p&gt;If you were an exploration geologist tasked by a mining company with finding a new gold deposit you would start with a geologic map.  In this sense, yes you would be using a map to locate potential gold deposits.  But you would also do a lot more research reading geological survey reports about the geologic history of the area, mine permit and mine history records of the area, and satellite images of your area of interest trying to come up with a hypothesis about why mineralization was found in particular areas (where old mines are) and not in other areas.  If you are looking in particular for gold you would decide whether you are going to concentrate on placer gold, deposited in stream valleys after weathering from source deposits elsewhere, or if you are going to look for hidden geothermal mineral veins that may hold some gold.  The history of mining in an area is probably a good guide to which will be productive.  Working for a company, you would probably also purchase field notes, drilling records, geochemical surveys, etc. done by previous companies working in the area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And all this research is done before doing any field work.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if I expand the meaning of your question to &quot;Is it possible to locate potential gold deposits through research&quot; the answer is yes.  If you want to use just the map the answer is no.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2017-07-11T04:02:32.033" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10793" PostTypeId="2" ParentId="10786" CreationDate="2017-07-11T04:19:04.933" Score="1" Body="&lt;p&gt;I disagree with John that a &quot;true fossil&quot; still has a component of the original material.  A trilobite shell that has had its chitin replaced with silica is a fossil even though all the original chitin is gone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not sure what your textbook's author is saying about a fossil that is the result of a shell's diagenesis (change in form as it fossilizes) could create a pseudomorph or impression.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Usually a pseudomorph is a term for a false fossil, something that looks like it was alive but was produced only from inorganic chemical reactions - like rust staining of sandstone producing a shell-like pattern.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An impression is usually the term for something like fossil tracks or burrows that show evidence for life in the geologic past, but are not themselves the preservation of a life form.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2017-07-11T04:19:04.933" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="10794" PostTypeId="2" ParentId="10766" CreationDate="2017-07-11T04:43:14.783" Score="2" Body="&lt;p&gt;Coring is not done continuously in oil drilling, but is done selectively when it is determined that the information obtained is worth the cost.  As blacksmith37 notes the crushed rock flushed from the hole by the drilling fluid is the primary way of determining information about the formations the well is going through.  But if an oil company needs a solid sample for measuring formation properties for, for instance, modeling a reservoir on a computer they have special drills that can be put down the hole and that capture the core produced.  The core drill assembly at the base, just inside the core has a slip collar that while drilling slides down the core but when the drill string is pulled up grabs onto the core, holding it in the sample tube and also breaking off the core at the bottom.  To see a diagram check out page 8 of &lt;a href=&quot;http://www.halliburton.com/public/sdbs/sdbs_contents/Brochures/Web/H03023.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this brochure on coring services&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2017-07-11T04:43:14.783" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10795" PostTypeId="2" ParentId="10787" CreationDate="2017-07-11T04:54:48.940" Score="-2" Body="&lt;p&gt;Most of the most productive gold mines are in locations where the mineral was brought up from deeper in the earth in extinct volcanic shafts and magma plumes.  Gold is a heavy metal so when the earth was first formed and was much hotter and many of the elements and compounds that are now solid were in hot molten form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At this early stage, it makes sense that the heavier and denser elements and compounds would have sunk deeper into the earth and lighter ones to float to the surface. If you pour oil into the water, the oil is less dense and floats to the surface.  The same principle applies.  Gravity pulls the denser material down closer to the center of the earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And that is what we see when we do seismic sonograms, and other analysis methods to reveal the earth's composition.  Silicon has an atomic weight of 28 and is thus a lighter element so it is found in abundance in almost all surface rocks and sands in the earth's crust.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As we go deeper the composition shifts to heavier and heavier elements.  The earth's core is mainly iron.  Since gold is even denser and heavier than iron it should be found in much more abundance relatively speaking at earth's core than at the surface.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We must emphasize that gold is a rare element in the earth and the universe in general for the following reasons.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;All elements other than Hydrogen and Helium and counting up in atomic number to iron are formed from the nuclear fusion in stars.  All elements heavier the iron, gold among them, can only be formed in the supernova explosion that occurs at the end of a massive star's life.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Gold is not at any end of any radioactive decay chain from heavier unstable element radioactive isotopes. Uranium 238 will decay over billions of years into lead and some other elements but never into gold.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;So gold, platinum, and other similar elements are rare because they are only formed in supernova explosions and no other process.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Getting back to answer your question, the only way to bring up the heavier and denser elements like gold back up to the earth's crust is through volcanic eruptions and magma plumes rising up from the interior.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, your best bet would be to investigate the igneous rocks in volcanic shafts, former eruptions, magma plumes, etc.  The other surface characteristics you mentioned like surface vegetation are irrelevant. &lt;/p&gt;&#xA;" OwnerUserId="8212" LastEditorUserId="2536" LastEditDate="2017-07-11T05:14:53.640" LastActivityDate="2017-07-11T05:14:53.640" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10797" PostTypeId="1" AcceptedAnswerId="10798" CreationDate="2017-07-11T05:57:24.403" Score="5" ViewCount="251" Body="&lt;p&gt;I was looking at &lt;a href=&quot;https://darksky.net/forecast/23.7594,90.3788/ca12/en&quot; rel=&quot;nofollow noreferrer&quot;&gt;this website&lt;/a&gt; and surprised to see that a cold area is surrounded by much hotter area. My understanding is that from the equator the more north/south direction one goes, the colder area one would encounter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But why this colder place is surrounded by hotter area? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3Q0oP.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3Q0oP.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="9543" LastEditorUserId="2536" LastEditDate="2017-07-11T06:24:24.820" LastActivityDate="2022-12-17T07:13:02.143" Title="Why is this area colder than the surrounding hotter area?" Tags="|meteorology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10798" PostTypeId="2" ParentId="10797" CreationDate="2017-07-11T06:06:48.517" Score="7" Body="&lt;p&gt;The Himalayas and the Tibetan Plateau have high elevation and temperature drops with altitude up until the tropopause. The temperature on the map is measured and modeled on the land surface, regardless of elevation. You can also see that the temperatures in e.g. Ethiopia and the Caucasus Mountains are lower than surrounding lowlands. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At latitudes around 30 degrees (north and south), the air is dry and hot due to &lt;a href=&quot;http://www.metoffice.gov.uk/learning/learn-about-the-weather/how-weather-works/global-circulation-patterns&quot; rel=&quot;noreferrer&quot;&gt;global circulation pattern&lt;/a&gt;. The weather patterns are also controlled by the topography, humid air can't pass the mountain range as it's forced to an altitude where the temperature force it to condensate. That is why the Gobi desert is hot and warm in the summer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope this answers your question. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-07-11T06:22:55.893" LastActivityDate="2017-07-11T06:22:55.893" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10799" PostTypeId="2" ParentId="10782" CreationDate="2017-07-11T06:09:09.000" Score="1" Body="&lt;p&gt;** &lt;strong&gt;All of the links given with times will need to be adjusted to current dates if reading this at later times or else will appear dead&lt;/strong&gt; **&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once upon a time I dealt with such files, but not in quite a few years... and Google wasn't the best help at first in finding documentation on what the .ascii is exactly... but thanks to Kevin Goebbert's code &lt;a href=&quot;https://github.com/rsignell-usgs/notebook/blob/master/Cartopy/4-panel-plot.py&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, I was able to find the description page for the model in question is located by removing the .ascii and inputs (and thus &lt;a href=&quot;http://nomads.ncep.noaa.gov:9090/dods/gfs_0p50/gfs20170707/gfs_0p50_12z&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And so right now it lists:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Longitude:  &#xA;0.00000000000°E to 359.50000000000°E&#xA;     (720 points, avg. res. 0.5°)&#xA;Latitude:   &#xA;-90.00000000000°N to 90.00000000000°N&#xA;     (361 points, avg. res. 0.5°)&#xA;Altitude:   &#xA;1000.00000000000 to 1.00000000000&#xA;     (47 points, avg. res. 21.717)&#xA;Time:   &#xA;12Z07JUL2017 to 12Z17JUL2017&#xA;     (81 points, avg. res. 0.125 days) &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The p50 indicates a grid space of only half a degree in that file, so you couldn't actually use your point in this moel.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, use &lt;a href=&quot;http://nomads.ncep.noaa.gov:9090/dods/gfs_0p25/gfs20170707/gfs_0p25_12z.ascii?tmax2m[0:0][0:0][0:0]&quot; rel=&quot;nofollow noreferrer&quot;&gt;the 0.25 resolution instead&lt;/a&gt; (&lt;a href=&quot;http://nomads.ncep.noaa.gov:9090/dods/gfs_0p25/gfs20170707/gfs_0p25_12z&quot; rel=&quot;nofollow noreferrer&quot;&gt;description&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So first is time first is time, the second is longitude points starting at the Prime Meridian and going east, and the third is latitude starting at the South Pole and going north.  (GFS time steps have always been a mire... but based on &lt;a href=&quot;http://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/gfs.2017062706/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this full list&lt;/a&gt; of data files and the info page previously given, it indeed appears the data provided here is just every 3 hours for the first 10 days.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to pick your value for the second input, it'd be something like  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;ifpositive: (longitude)*4 - 1&#xA;  ifnegative: (180+longitude)*4 + 719&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And for latitude:  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;360+(latitude)*4&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And so if I didn't make a mistake, that'd be &lt;a href=&quot;http://nomads.ncep.noaa.gov:9090/dods/gfs_0p25/gfs20170707/gfs_0p25_12z.ascii?tmax2m[0:80][505:505][1124:1124]&quot; rel=&quot;nofollow noreferrer&quot;&gt;this point&lt;/a&gt; (lat gridpoint 505, lon gridpoint 1124).&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2017-07-11T06:09:09.000" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10800" PostTypeId="1" CreationDate="2017-07-11T21:00:22.530" Score="1" ViewCount="209" Body="&lt;p&gt;I’ve had a simple puzzlement concerning the ozone layer.  Succinctly, the troposphere is largely and preferably ozone free.  When it thermally rises at the tropics to become the stratosphere molecular oxygen cleaves under actinic radiation to from nascent oxygen that, in turn joins with molecular oxygen to form ozone.  The stratospheric ozone, of course, is vital to protect against harmful radiation.  Then at the polar vortices the flow once again returns to the troposphere.  Ozone is undesirable in the troposphere and is removed at this point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this is accurate (?), why would halides that disassociate ozone (in conjunction with ice crystals only present at the Antarctic pole) be seen as adverse?&lt;/p&gt;&#xA;" OwnerUserId="9548" LastActivityDate="2018-12-10T08:44:46.523" Title="Is Ozone Layer a Valid Concern" Tags="|ozone|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="10801" PostTypeId="2" ParentId="10797" CreationDate="2017-07-11T22:07:26.357" Score="3" Body="&lt;p&gt;Look at how similar the elevation map is of the region:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9MANs.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9MANs.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;sup&gt;&lt;sub&gt;From Wikipedia&lt;/sub&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;And that goes really well with &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9038/why-is-it-colder-in-the-mountains-than-at-sea-level&quot;&gt;Why Is It Colder in the Mountains Than at Sea Level&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As &lt;a href=&quot;https://earthscience.stackexchange.com/a/10798/6298&quot;&gt;tbb noted&lt;/a&gt;, the band near 30 north/south tends overall (climatologically) to be drier and hotter due to &lt;a href=&quot;https://en.wikipedia.org/wiki/Subtropical_ridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;descending air&lt;/a&gt; caused by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hadley_cell&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hadley circulation&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;As to why this area stands out in comparison with other locations at the same latitude, the moisture in the air has quite a bit to do with it:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IDK5F.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IDK5F.png&quot; alt=&quot;dewpoint 071117&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;sub&gt;&lt;sup&gt;Today's &lt;a href=&quot;https://www.washingtonpost.com/news/capital-weather-gang/wp/2013/07/08/weather-weenies-prefer-dew-point-over-relative-humidity-and-you-should-too/?utm_term=.f3a731b37038&quot; rel=&quot;nofollow noreferrer&quot;&gt;dew points&lt;/a&gt;, courtesy of &lt;a href=&quot;http://www.pivotalweather.com/model.php?m=gfs&amp;amp;p=sfctd_c&amp;amp;rh=2017071112&amp;amp;fh=0&amp;amp;r=as&amp;amp;dpdt=&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pivotal Weather&lt;/a&gt;&lt;/sup&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;Indeed, you can see it is fairly dry over parts of central and western China compared to many other places, such as eastern China and back nearer Europe... due in part to the affects of the mountains and distance from large bodies of water... though you may also notice other spots to the west do show comparable moisture for this date despite producing lower temperatures.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/c/c9/Asia_satellite_plane.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ground cover&lt;/a&gt; differences are part of the reason (more plants = more area the solar energy is distributed into, plus typically store moisture, equating to slower temperature changes).&lt;/p&gt;&#xA;&lt;p&gt;And then wind direction gives one final explanation why it's not as warm further to the west:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kWDW1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kWDW1.jpg&quot; alt=&quot;winds 071117&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The northerly winds have been in place for a while back in &lt;a href=&quot;https://www.google.com/maps/place/Asia/@41.9220317,75.535738,4z/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kazakhstan and Uzbekistan&lt;/a&gt; have brought slightly cooler temperatures down from the north, whereas the flow into China is less consistent and has only recently started shifting.  Even in the summer, wind changes and even fronts are still often very important in the temperature layout.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-12-17T07:13:02.143" LastActivityDate="2022-12-17T07:13:02.143" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="10802" PostTypeId="2" ParentId="9853" CreationDate="2017-07-11T22:51:38.763" Score="3" Body="&lt;p&gt;This is a complex question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will assume the following to be able to frame an answer properly:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Let's take a general cold area as a baseline, such as the High Arctic or 70°+ N latitude;&lt;/li&gt;&#xA;&lt;li&gt;The reference for this example can be &lt;a href=&quot;http://climate.weather.gc.ca/climate_normals/results_1981_2010_e.html?searchType=stnName&amp;amp;txtStationName=pond&amp;amp;searchMethod=contains&amp;amp;txtCentralLatMin=0&amp;amp;txtCentralLatSec=0&amp;amp;txtCentralLongMin=0&amp;amp;txtCentralLongSec=0&amp;amp;stnID=1774&amp;amp;dispBack=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pond Inlet&lt;/a&gt;, on Baffin Island, an example where long-term records are available (72° N). The following data assumptions will be based on the &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/land-based-station-data/land-based-datasets/climate-normals&quot; rel=&quot;nofollow noreferrer&quot;&gt;normals&lt;/a&gt; provided by this station. But what is discussed is likely to be valid for a large area of the High Arctic - like 70°+ N latitude;&lt;/li&gt;&#xA;&lt;li&gt;In this area, the normal (1981-2010) mean annual air temperature is -14.6° C is fairly representative&lt;/li&gt;&#xA;&lt;li&gt;Also, in this area, the normal yearly degree days to reach thawing (&lt;a href=&quot;http://psc.apl.washington.edu/nonwp_projects/landfast_ice/freezing.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;TDD&lt;/a&gt; - the sum of daily average temperatures above 0° C) is 473 degrees.&lt;/li&gt;&#xA;&lt;li&gt;The bulk of the TDD sum (473 degrees) occurs during June, July and August; only 2 degrees in May, 31 in September and 1 in October, so thawing is most likely minimal outside these three months. As a consequence there are two fairly distinct seasons: the thaw season (summer, duration 3 months) and the freezing season (winter, duration 9 months).&lt;/li&gt;&#xA;&lt;li&gt;Pro-glacial rivers are not considered (river taking their source from glaciers, different story)&lt;/li&gt;&#xA;&lt;li&gt;Lakes are not considered (different story)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;This all means that the cold region's rivers are not thermally static through time. Even in the High Arctic, an icy river can be frozen along both its vertical and horizontal profile during a good part of the long winter, and thaw completely during the short summer. But other considerations exists.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's examine what can happen when the snow thaw is sometime in June. The discharge signature for a river in the High Arctic is &lt;strong&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/River_regime#Classification&quot; rel=&quot;nofollow noreferrer&quot;&gt;nival&lt;/a&gt;&lt;/strong&gt;, with a discharge peak occurring during early summer due to the massive input of snowmelt water, and additional weaker responses from the small rain amounts. This looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UYBIi.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UYBIi.png&quot; alt=&quot;Source: Woo (2012) Permafrost Hydrology &quot;&gt;&lt;/a&gt;&#xA;&lt;strong&gt;Source:&lt;/strong&gt;  &lt;a href=&quot;http://www.springer.com/gp/book/9783642234613&quot; rel=&quot;nofollow noreferrer&quot;&gt;Woo (2012) Permafrost Hydrology&lt;/a&gt;, fig 10.14; from river McMaster, 74° N.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;So what basically is happening here?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Peak is during June.&lt;/li&gt;&#xA;&lt;li&gt;Afterward, once the snow had melted completely, the discharge lowered drastically.&lt;/li&gt;&#xA;&lt;li&gt;By late August, there is almost no more water in the river, and it may be completely recessed.&lt;/li&gt;&#xA;&lt;li&gt;Then winter arrives.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;During the next several months, snow will accumulate in the landscape. In a landscape there are snow sources and snow sinks (&lt;a href=&quot;http://dx.doi.org/10.1002/(SICI)1099-1085(199709)11:11%3C1451::AID-HYP449%3E3.0.CO;2-Q&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pomeroy et al. 1997&lt;/a&gt;);  sources may be higher lands, outcrops, plateaus, or exposed areas, and sinks lower areas, such as depression or channels. Our typical nival river will be a sink in this context.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because of this, it is not only patches of ice that will be found in the river channel, but tightly packed snow that builds up at the base when it is a thick layer (or is looser when the snowpack is thin). In any case snow will be most likely metamorphized in structure as a result of surface thaw and the water snowmelt infiltration -&gt; snow percolation -&gt; re-ice events during the winter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is happening in June, in more detail?&lt;/strong&gt;&lt;br&gt;&#xA;Let's analyse this further with a more detailed (though raw and unprocessed) graph from a small stream in a gully near Pond Inlet, with resolution available up to the nearest day:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eOosf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eOosf.png&quot; alt=&quot;Pressure and temperature in the bed of a stream gully, summer 2010&quot;&gt;&lt;/a&gt;&#xA;&lt;strong&gt;Source:&lt;/strong&gt; Stream temperature and water pressure in a stream located in a gully on Bylot Island, 85 km from Pond Inlet; raw, partial data from my PhD work. Temperature in blue, scale on the right, and pressure in black, scale on the left. Dates on the x-axis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By looking at the pressure line (in black), it can be interpreted that there was no water until June 16th when the pressure increased drastically. Temperature (in blue) stayed at -2 °C until the 17th. Water was infiltrating into the snow at this time, contributing to the slowly rising pressure, but the water did not reach the sensor until the 17th when the temperature starts rising. During the 18th, temperature rises to -0.5 °C, then hovers in these negative temperature for almost 24 hours. This supercooled water temperature is due to a mix of factors, such as increased pressure from the water on snow, the release of latent heat due to the metamorphized snow thawing, and the near zero temperature of the water, in balance with the snow. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When a critical mass of water accumulates near the logger emplacement in the stream channel, the bulk of the snow melt and water then shifts to positive temperatures, still near zero, with diurnal/nocturnal shifts (blue line becoming wave-like).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: This small stream is minimally impacted by the geothermal flux (heat flowing up from the ground below).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Summary&lt;/strong&gt;, in relation to the questions:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Temperature will be mostly above zero; but may be under and near zero for short periods when the water is mixing with snow and ice in a channel;&lt;/li&gt;&#xA;&lt;li&gt;Yes - as shown in the second figure, water was at -0.5 °C for about 24 hours;&lt;/li&gt;&#xA;&lt;li&gt;I think it is common, as thawing temperatures do reach very high latitudes such as Ward Hunt Island (83° N), and thus this process likely concerns a large area, including probably the entire Canadian Archipelago (lowlands at least).  But this transition process does not last long at any location. Additionally, it is worth noting that High Arctic rivers are difficult to access, monitor, and study, so it is difficult to generalize this with confidence; other factors or contexts could exist where conclusions may differ.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="1411" LastEditorUserId="6298" LastEditDate="2017-07-12T06:09:54.917" LastActivityDate="2017-07-12T06:09:54.917" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10803" PostTypeId="2" ParentId="10761" CreationDate="2017-07-12T02:17:23.600" Score="3" Body="&lt;p&gt;There is a balance between precipitation on the one hand, and sublimation and outflow on the other. Ice evaporates directly to water vapor, especially during the summers. The thicker the ice, the greater the pressure at the bottom of the ice owing to the weight of the overlying ice, and hence the faster the outflow. The thicker the ice, the less the precipitation, because the less the atmosphere above the ice sheet. The pressure at the bottom of an ice sheet 250 km thick, or even 125 km thick, would be so great that outflow would be very much faster than at present, and very much exceed even current average precipitation of perhaps 1 inch per year. Indeed precipitation would be ZERO for such a thick ice sheet because its height would be above any appreciable atmosphere. Even neglecting sublimation and outflow, an ice sheet could never attain a thickness of 125 km, much less 250 km, because precipitation over the ice sheet would vanish well before such a thickness was attained.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastEditorUserId="8382" LastEditDate="2017-07-17T02:57:29.950" LastActivityDate="2017-07-17T02:57:29.950" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10804" PostTypeId="2" ParentId="2519" CreationDate="2017-07-12T05:39:05.697" Score="11" Body="&lt;p&gt;The turquoise to sky-blue color appearance of freshwater bodies are nicely explained with examples in a 2016 paper by Kumar entitled &amp;quot;&lt;a href=&quot;https://www.researchgate.net/publication/311770515_STUDY_ON_TURQUOISE_AND_BRIGHT_SKY-BLUE_APPEARING_FRESHWATER_BODIES&quot; rel=&quot;noreferrer&quot;&gt;&lt;strong&gt;Study on turquoise and bright sky-blue appearing freshwater bodies&lt;/strong&gt;&lt;/a&gt;&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;In this paper, the author explains the cause of these shades of greenish-blue shades found in freshwater bodies around the world and proposes a classification/categorization of such freshwater bodies. the author has classified different turquoise to sky-blue appearing freshwater bodies into two major classes:&lt;/p&gt;&#xA;&lt;p&gt;1)Natural&lt;/p&gt;&#xA;&lt;p&gt;2)Anthropogenic&lt;/p&gt;&#xA;&lt;p&gt;Such water bodies with causal factor of natural origin are placed under 'natural' and causal factor of non-natural (anthropogenic) origin are placed under 'anthropogenic' category. The 'natural' category has been further sub-classified into three sub-class : a. Glacial Fed (streams, lakes appears turquoise to sky-blue due to scattering of light by glacial flour (rock flour), ex- Phoksundo lake (Nepal), Moraine lake (canada), etc .&#xA;b. Volcanic and Hydrothermal: Lakes and rivers in volcanic region and of hydrothermal origin also appear turquoise to sky-blue. For example, kawah Ijen (Indonesia), Yudamari lake (Japan) which appears blue as a result of scattering from sulphate and ferrous particles. Rio celeste in another river in Costa Rica which appears turquoise as a result of scattering from aluminosilicate particles. c. Calcium carbonate rich: Calcium carbonate rich freshwater bodies also appear turquoise to sky-blue as a result of scattering from suspended calcite particles. Example,Havasu creek (grand canyon), Bear lake(Utah), Plitvice lakes (Croatia).&lt;/p&gt;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;&lt;p&gt;Anthropogenic : The author has discussed two water bodies appearing turquoise to sky-blue. Lukha river (Wah Lukha) which flows in meghalaya (India) turns turquoise every year in winter season, real cause not known but coal and limestone mining cited as a reason. Wilge river (S Africa) flows in coal mine affected area appears turquoise and aluminium has been cited as causing agent.&lt;/p&gt;&#xA;&lt;p&gt;I would recommend reading the paper if you are interested in getting a deeper understanding. Picture 1. Different Glacial-fed freshwater bodies. 2. Calcium carbinate rich freshwater bodies. 3. River appearing turquoise as result of anthropogenic activities.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/NXWSW.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NXWSW.png&quot; alt=&quot;different glacial lakes&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/PYCSU.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PYCSU.png&quot; alt=&quot;Calcium carbonate rich &quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/JaZfx.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JaZfx.png&quot; alt=&quot;anthropogenic&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="9553" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-08-01T04:12:53.480" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10806" PostTypeId="1" CreationDate="2017-07-12T09:18:21.120" Score="5" ViewCount="113" Body="&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/9999/6031&quot;&gt;This informative answer&lt;/a&gt; describes some processes in atmospheric chemistry and mentions &quot;sulphate particles&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Actually I realize that I don't know what a 'sulphate particle' really is, though I've heard the term many times. &lt;a href=&quot;https://en.wikipedia.org/wiki/Sulfate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sulphate is an ion, or an anion&lt;/a&gt;, so the term could refer to a solid particle of some sulphate salt (e.g. calcium sulphate, sodium sulphate) or balanced by some other caution in solution in a water droplet, but is there such a thing as a particle made of &quot;pure sulphate&quot;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\hskip3.8cm$&lt;/span&gt;&lt;img src=&quot;https://i.stack.imgur.com/1OGxx.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\hskip3.7cm$&lt;/span&gt;&lt;strong&gt;above:&lt;/strong&gt; &quot;Sulfate-ion-2D-dimensions&quot;, from &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Sulfate-ion-2D-dimensions.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2019-05-26T05:46:34.083" LastActivityDate="2019-05-26T05:46:34.083" Title="What are 'sulphate particles' in the context of atmospheric chemistry?" Tags="|atmosphere|atmospheric-chemistry|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="10807" PostTypeId="1" CreationDate="2017-07-12T11:41:45.243" Score="4" ViewCount="642" Body="&lt;p&gt;If you take a look at this picture you can see what looks like almost nicely cut out 'roads' between the mountains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://www.awesomestories.com/images/user/4ae0e8b631.jpg&quot; alt=&quot;Himalayan mountains&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What forces are responsible for this?&lt;/p&gt;&#xA;" OwnerUserId="9555" LastEditorUserId="11908" LastEditDate="2019-03-13T05:02:06.137" LastActivityDate="2019-03-13T05:02:06.137" Title="How are 'road-like passages' between Himalayan mountains formed?" Tags="|mountains|glaciology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10808" PostTypeId="2" ParentId="10807" CreationDate="2017-07-12T12:01:36.367" Score="12" Body="&lt;p&gt;It's a &lt;a href=&quot;https://nsidc.org/cryosphere/glaciers/questions/what.html&quot; rel=&quot;noreferrer&quot;&gt;glacier&lt;/a&gt;, it this case the &lt;a href=&quot;https://en.wikipedia.org/wiki/Baltoro_Glacier&quot; rel=&quot;noreferrer&quot;&gt;Baltoro Glacier&lt;/a&gt; in Karakoram, Pakistan. The road-like pattern is formed as the glacier slowly flows towards lower altitude from a nearby ice-cap or &lt;a href=&quot;http://www.antarcticglaciers.org/modern-glaciers/introduction-glacier-mass-balance/&quot; rel=&quot;noreferrer&quot;&gt;accumulation zone&lt;/a&gt;. Rocks and dirt is transported both within the ice and on the surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With a closer look, the surface is rarely smooth, but often deep trenches, &lt;a href=&quot;https://en.wikipedia.org/wiki/Crevasse&quot; rel=&quot;noreferrer&quot;&gt;cravasses&lt;/a&gt;, and meltwater channels are formed as the glacier moves. On a human timescale, the glaciers crawl slowly, but from a geological perspective &lt;a href=&quot;https://www.youtube.com/watch?v=RXROvFbEXKE&quot; rel=&quot;noreferrer&quot;&gt;they are fast&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/s7QLn.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/s7QLn.jpg&quot; alt=&quot;https://en.wikipedia.org/wiki/Glacier#/media/File:GornerGlacier_002.jpg&quot;&gt;&lt;/a&gt;&#xA;&lt;em&gt;Closeup of a glacier with crevasses. (By Roylindman at en.wikipedia, CC BY-SA 3.0)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Under the glacier, a U-shaped valley is formed as the glacier erode the bedrock. Depending on the dynamics of the glacier and the erosion, the glacier might also appear clean, without sediment on the surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/omQa1.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/omQa1.jpg&quot; alt=&quot;Private photo&quot;&gt;&lt;/a&gt;&#xA;&lt;em&gt;Large glacier without sediments, but also with a very uneven surface due to the movements of the glacier (Wilkes Land).&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="1411" LastEditDate="2017-07-12T15:16:52.817" LastActivityDate="2017-07-12T15:16:52.817" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10810" PostTypeId="1" AcceptedAnswerId="13251" CreationDate="2017-07-12T14:25:27.730" Score="8" ViewCount="397" Body="&lt;p&gt;&lt;strong&gt;update 2:&lt;/strong&gt; FIRST images of A-68 iceberg &lt;em&gt;not taken from a satellite in space&lt;/em&gt; but from the air are out. On this &lt;a href=&quot;https://earthobservatory.nasa.gov/blogs/fromthefield/2017/11/13/the-gravity-of-larsen-c/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA Earth Observatory&lt;/a&gt; web page are areal images from NASA's &lt;a href=&quot;https://www.nasa.gov/mission_pages/icebridge/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Operation IceBridge&lt;/a&gt; taken from a P-3 aircraft. Will the placement of a GPS tracker/weather monitor or two, or even a seismometer be next?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dA7Jl.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dA7Jl.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; The edge of A-68, the iceberg the calved from the Larsen C ice shelf. Photo by NASA/Nathan Kurtz.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;update 1 :&lt;/strong&gt; According to the BBC Article &lt;a href=&quot;http://www.bbc.com/news/science-environment-41553687&quot; rel=&quot;nofollow noreferrer&quot;&gt;British mission to giant A-68 berg approved&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The British Antarctic Survey has won funding to visit the berg and its calving zone in February next year.&lt;/p&gt;&#xA;&lt;p&gt;It will use the Royal Research Ship James Clark Ross.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This would present a potential opportunity to add some ground-truth telemetry to A-68. Details of it's short term and long term motion could then be monitored with higher resolution both in space and time than what can be obtained from periodic photographs from polar-orbiting satellites.&lt;/p&gt;&#xA;&lt;p&gt;Video: &lt;a href=&quot;https://youtu.be/OT-gW9sZn_8&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://youtu.be/OT-gW9sZn_8&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BkI35.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BkI35.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Study of the movement of cold fresh water in the form of ice bergs is important for climate models. The &lt;em&gt;plain language summary&lt;/em&gt; in the recent paper &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2016JC012513/abstract;jsessionid=5B3A2466125017BA3B5AFBD62333E610.f04t01&quot; rel=&quot;nofollow noreferrer&quot;&gt;A simulation of small to giant Antarctic iceberg evolution: Differential impact on climatology estimates&lt;/a&gt;; Rackow, T., C. Wesche, R. Timmermann, H. H. Hellmer, S. Juricke, and T. Jung (2017), J. Geophys. Res. Oceans, 122, 3170–3190, doi:&lt;a href=&quot;http://dx.doi.org/10.1002/2016JC012513&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.1002/2016JC012513&lt;/a&gt; says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Antarctic icebergs are large blocks of frozen fresh water that melt around the Antarctic continent while moving under the influence of winds, sea ice, and ocean currents. Small icebergs (2.2km) are mainly driven by winds and ocean currents, whereas giant icebergs&#xA;(&amp;gt; 10 km) tend to ‘surf’ the tilted sea surface and are less sensitive to changes in the wind. The relative importance between melting at the iceberg’s base and mass loss at the side walls is also different for small and large icebergs.We present a computer simulation of Antarctic iceberg movement and melting that includes not only small icebergs, but at the same time also larger icebergs with side lengths of 10 km or more. The study highlights the necessity to account for larger icebergs in order to obtain an accurate depiction of the spatial distribution of iceberg meltwater, which, e.g., stabilizes and fertilizes the upper water column and thus supports phytoplankton growth. Future climate change simulations will benefit from the improved distribution, where the impact of iceberg melting is likely to increase due to increased calving from the Antarctic ice sheet.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The authors describe the use of the &lt;a href=&quot;http://www.geosci-model-dev.net/7/663/2014/gmd-7-663-2014-discussion.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Finite Element Sea ice-Ocean Model&lt;/a&gt;&#xA;(FESOM) to address the effect of the 3 dimensional ocean currents and wind pattern on the paths of icebergs and their addition of cold fresh water to the ocean.&lt;/p&gt;&#xA;&lt;p&gt;At some point any predictive model will be compared against measured data, and traditionally satellite imaging provides the capability to track large numbers of icebergs with a wide range of sizes.&lt;/p&gt;&#xA;&lt;p&gt;From the new BBC article &lt;a href=&quot;http://www.bbc.com/news/science-environment-40635883&quot; rel=&quot;nofollow noreferrer&quot;&gt;Drifting Antarctic iceberg A-68 opens up clear water&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A-68 should follow the highway up the eastern coast of the Antarctic Peninsula, leading from the Weddell Sea towards the Atlantic.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;It will most likely follow a northeasterly course, heading roughly for South Georgia and the South Sandwich Islands,&amp;quot; Dr Rackow told BBC News. &amp;quot;It will be very interesting to see whether the iceberg will move as expected, as a kind of 'reality-check' for the current models and our physical understanding.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The large size (~6,000 km^2) of the recently calved iceberg A-68 from the Larson-C ice shelf suggests it will will be relatively long lived, and so telemetry equipment placed on it is likely to collect data for a longer time than smaller ice bergs. I'm wondering if it might in fact be able as a sort of &amp;quot;meteorological station&amp;quot; of sorts, recording a variety of temperatures and currents and relaying the data via satellite.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;But my question&lt;/strong&gt; is not if that is possible, but if it is likely to be done. Will A-68 get GPS beacons or more elaborate environmental telemetry in order to measure the local conditions? Having both the actual movement data together with the local environmental data may be of more value than satellite reconnaissance alone.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;More information available at this question and &lt;a href=&quot;https://earthscience.stackexchange.com/a/9475/6031&quot;&gt;answers&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;As noted in &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9262/#comment21352_9262&quot;&gt;this comment&lt;/a&gt; and by &lt;a href=&quot;http://www.bbc.com/news/science-environment-40321674&quot; rel=&quot;nofollow noreferrer&quot;&gt;the BBC&lt;/a&gt; and the &lt;a href=&quot;https://www.washingtonpost.com/news/energy-environment/wp/2017/07/12/one-of-the-biggest-icebergs-in-recorded-history-just-broke-loose-from-antarctica/?utm_term=.41811447b814&quot; rel=&quot;nofollow noreferrer&quot;&gt;Washington Post&lt;/a&gt;, a very large chunk of the Larson C ice shelf in the Antarctic has calved and is now a free iceberg.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; Photo from &lt;a href=&quot;http://www.bbc.com/news/science-environment-40635883&quot; rel=&quot;nofollow noreferrer&quot;&gt;BBC&lt;/a&gt;, source: &lt;a href=&quot;http://dx.doi.org/10.1002/2016JC012513&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rackow et al.&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Mx8VA.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Mx8VA.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; Photo from &lt;a href=&quot;http://www.bbc.com/news/science-environment-40635883&quot; rel=&quot;nofollow noreferrer&quot;&gt;BBC&lt;/a&gt;, source: Deimos Imaging an UrtheCast company&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LcvtX.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LcvtX.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-04-05T03:24:09.333" Title="The giant 6,000 km$^2$ iceberg A-68; will ground-truth telemetry supplement satellite tracking data?" Tags="|glaciology|remote-sensing|antarctic|gnss|gps|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="10813" PostTypeId="1" AcceptedAnswerId="10815" CreationDate="2017-07-12T16:59:08.623" Score="6" ViewCount="4391" Body="&lt;p&gt;Students of geology are introduced to in their petrology course, (or used to be), to the terms &quot;acidic&quot;, &quot;basic&quot;, and the associated term &quot;intermediate&quot; in relation to %$SiО­­­_{2}$ in igneous rocks, where, depending on whom you read:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Acidic: rocks with above 63%/65% silica (mostly feldspar minerals and&#xA;quartz), e.g. granite.&lt;/li&gt;&#xA;&lt;li&gt;Intermediate: rocks with 50%/55% - 63%/65% silica, e.g. syenite, trachyte. &lt;/li&gt;&#xA;&lt;li&gt;Basic: rocks that are about 45 to 55% silica&#xA;(mostly mafic minerals plus plagioclase feldspar and/or feldspathoid&#xA;minerals), e.g. basalt.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Of course, if they go on to work with chemists in, say, an environmental geology practice, this causes no small amount of contention and sometimes confusion between the geo and the chemist, who, of course, understands the terms &quot;acidic&quot;, etc. in the classic chemical sense, of $pH = -log [H^+]$, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How did the terms &quot;acidic&quot; and &quot;basic&quot; come to be associated with %$SiO_2$ in igneous rocks, in contrast to the classical chemical definition?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note to Responders: Apologies for my ignorance. It's been over 30 years since I studied and worked in (exploration) geology. So my knowledge of current terminology is a little rusty, especially since my major experience has been that of an geologist transmogrified into an electronic engineer.&lt;/p&gt;&#xA;" OwnerUserId="9552" LastEditorUserId="1149" LastEditDate="2017-07-13T10:11:29.493" LastActivityDate="2017-07-13T10:11:29.493" Title="How did the terms &quot;acidic&quot; and &quot;basic&quot; come to be associated with $SiO_2$ in igneous rocks?" Tags="|geology|petrology|terminology|igneous|history-of-science|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10814" PostTypeId="2" ParentId="10546" CreationDate="2017-07-12T18:34:54.600" Score="2" Body="&lt;p&gt;Yes, they are called atmospheric tides. They can be caused by the gravitational effect of the moon on the atmosphere (lunar tides) and also differential solar heating (thermal tides). I believe you are asking about the former which is much weaker than the latter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can find more about it here: &lt;a href=&quot;https://www.springer.com/us/book/9789027726308&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.springer.com/us/book/9789027726308&lt;/a&gt;&#xA;and &lt;a href=&quot;https://physics.stackexchange.com/questions/201973/are-there-tides-in-the-atmosphere&quot;&gt;https://physics.stackexchange.com/questions/201973/are-there-tides-in-the-atmosphere&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="200" LastEditorUserId="200" LastEditDate="2017-07-12T21:33:24.103" LastActivityDate="2017-07-12T21:33:24.103" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10815" PostTypeId="2" ParentId="10813" CreationDate="2017-07-12T21:22:50.570" Score="6" Body="&lt;p&gt;The idea came from the theory that silicic acid was the chief form of silicon occurring in rocks.  Early attempts to classify minerals, placed some mineral specimens in groups based acid-base reactions and the hypothetical acid that mineral was derived.  Sulfates, phosphates, nitrates , and tungstates etc.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This thinking was the result of 19th century chemistry research which attempted to explain chemical reactions in terms of  acid-base reactions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Much of this terminology is still in use today even though it is considered archaic now. &lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-07-12T21:22:50.570" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10816" PostTypeId="1" AcceptedAnswerId="10817" CreationDate="2017-07-12T23:03:27.867" Score="16" ViewCount="4666" Body="&lt;p&gt;According to most &lt;a href=&quot;https://www.space.com/24854-how-old-is-earth.html&quot; rel=&quot;noreferrer&quot;&gt;articles&lt;/a&gt; I've read online, the estimated age of Earth is &lt;em&gt;4.5 billion years&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; How old is the Earth?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I actually want to confirm that this is the case. Maybe there are other famous theories saying it is 3 billion years old or 6, therefore my question.&lt;/p&gt;&#xA;" OwnerUserId="9562" LastEditorDisplayName="user12525" LastEditDate="2019-04-26T09:31:37.713" LastActivityDate="2022-05-15T16:17:21.067" Title="How old is the Earth?" Tags="|geology|earth-history|geochronology|dating|history-of-science|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10817" PostTypeId="2" ParentId="10816" CreationDate="2017-07-12T23:45:56.203" Score="27" Body="&lt;p&gt;Yes, the age of the Earth is about 4.5 billion years (4,500 million years). Your linked articles describes well &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4362/how-was-the-earth-formed?rq=1&quot;&gt;how it was formed&lt;/a&gt; and how we know about it. The uncertainty is less than 1% and depends partly on the radiometric dating methods and partly on the definitions. Sometimes the age is said to be 4.567 &lt;a href=&quot;https://en.wikipedia.org/wiki/Billion_years&quot; rel=&quot;noreferrer&quot;&gt;Ga&lt;/a&gt;, that might be a little too exact number to claim, but at least it's easy to remember. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I haven't heard any different age constraints that are scientifically founded, but before we had access to the methods and data we have today, there was a broader range of estimates. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Early estimates were based on the supposed &lt;a href=&quot;http://apps.usd.edu/esci/creation/age/content/failed_scientific_clocks/ocean_salinity.html&quot; rel=&quot;noreferrer&quot;&gt;increased salinity of the oceans&lt;/a&gt;, but those estimates fail to recognize that salt is also removed from the seawater in subduction zones and to form &lt;a href=&quot;https://en.wikipedia.org/wiki/Evaporite&quot; rel=&quot;noreferrer&quot;&gt;evaporites&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Noteworthy is &lt;a href=&quot;https://en.wikipedia.org/wiki/William_Thomson,_1st_Baron_Kelvin#Age_of_the_Earth:_geology_and_theology&quot; rel=&quot;noreferrer&quot;&gt;Lord Kelvin's&lt;/a&gt; very sensible estimate of 20–40 million years, published first in 1863. The estimate was based on the heat lost since formation and Earth's capacity to withhold its energy. Unfortunately, Lord Kelvin worked too early to know that $E=mc^2$, so energy is also generated within Earth and that is the main source of heat. He also didn't understand the Sun's &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2000JB900028/pdf&quot; rel=&quot;noreferrer&quot;&gt;source of energy and convection&lt;/a&gt; and therefore miscalculated the solar age constraint and Earth's heat flux. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://australianmuseum.net.au/radioactive-dating&quot; rel=&quot;noreferrer&quot;&gt;Radioactive decay&lt;/a&gt; is not only the source of heat but also the process we use to measure the age by radiometric methods. These methods became known decades later and quickly provided age constraints sin the right magnitude. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth scientists have assumed the deep time age of Earth since the antiques. It must have been frustrating for the early geologists to not be able to put a number of the Earth's age. As a rudiment of that time, we still use their &lt;a href=&quot;https://en.wikipedia.org/wiki/Geologic_time_scale#Terminology&quot; rel=&quot;noreferrer&quot;&gt;relative terminology&lt;/a&gt; to describe the development. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Our present estimate is based on a range of agreeing models and data. The Earth science community has, in general, moved on to new and more challenging questions. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-07-14T01:04:01.700" LastActivityDate="2017-07-14T01:04:01.700" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="10818" PostTypeId="2" ParentId="10511" CreationDate="2017-07-13T09:54:18.853" Score="0" Body="&lt;p&gt;In physics, you should  get the same result whichever way you calculate. As long as you do not make an error in calculations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Calculating the greenhouse effect using radiative transfer equation, we get a result pretty close to the observed one, even if we neglect effects such as turbulent heat fluxes as long as we get Planck optical depth right. And this is why I think, even without following their derivation, that they must  have made a massive error. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another reason for that is simple intuition that airless (shortwave) albedo must be unimportant on planets with large optical  depths (thick clouds) because at the surface you do not have much shortwave (solar) radiation anyway. The surface is dominated by longwave radiation (IR) which albedo is close to 0.0, anyway.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;" OwnerUserId="9567" LastEditorUserId="-1" LastEditDate="2018-11-20T16:00:22.447" LastActivityDate="2018-11-20T16:00:22.447" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="10820" PostTypeId="1" CreationDate="2017-07-13T19:21:43.377" Score="5" ViewCount="1765" Body="&lt;p&gt;I have read that these phenomena do not have an interaction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I would think if CFCs cause the ozone layer to thin, and more UV radiation enters the Earth system, the Greenhouse Effect would cause global warming would increase. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Will the infrared energy emitted by the Earth increase with a higher input of ultraviolet radiation?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="5851" LastEditorUserId="6298" LastEditDate="2017-07-24T04:21:48.483" LastActivityDate="2017-07-24T04:21:48.483" Title="Are greenhouse effect and ozone depletion correlated?" Tags="|climate-change|ozone|greenhouse-gases|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10821" PostTypeId="2" ParentId="10783" CreationDate="2017-07-13T19:46:44.640" Score="11" Body="&lt;p&gt;Etienne Godin mades some good points about various credibility problems with the paper. I decided to take a quick look at the actual content, to see if the authors have any good points. I'll summarize my findings in two broad categories.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Statements made without evidence&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The paper is poorly referenced, as Edienne Godin says. That in and of itself isn't necessarily a problem if the paper is able to make its own arguments. After all, Einstein couldn't rely on references to make his points about special relativity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the paper doesn't do a good job of providing internal evidence for some of its claims. The key foundation claim is that the various bodies creating global temperature estimates are systematically biasing the underlying GHCN climate data to show more warming than there actually is. Most of these claims appear on page 9 of the linked paper, or thereabouts. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The authors claim that there is an increase in climate sensing stations that are located at 'urban' airports; while providing no evidence about how airports are affected by urban heat island effects. The 'reference' blog linked from the paper makes claims about poorly sited meteorological stations being used in the data set, but has no systematic evidence (i.e. not anecdotal evidence) about how many stations are poorly sited, and if those numbers have fluctuated in the past. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The authors claim that &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Changes in  technology introduced new discrepancies through instrument&#xA;  biases  and forced related changes in siting.  In addition, over the &#xA;  past 100  plus years ,  the  daily  time of observation varied  from&#xA;  location to  location and often changed over time, which has a varying&#xA;  effect on  calendar day highs and lows and for which appropriate&#xA;  adjustments  to raw data  must be made.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, they provide no evidence as to how or in which direction modern instruments might be biased compared to older ones, nor do they provide any evidence that the time of observation has changed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These claims basically amount to a courtroom-style tactic of casting doubt on the prosecution's story. However, without evidence global temperature estimates are systematically biased, I'm inclined to trust the peer-reviewed work of the scientists who made these estimates in the first place.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Without evidence supporting these claims, the author's argument falls apart, in my opinion. The rest of the paper points to the corrections made in older data, showing that corrections made over the last 25 years have steadily increased the magnitude of global temperature rise in the 20th century. These historical data corrections are made for a purpose. If the authors of this paper think the historical data corrections are not being done properly, then they have to attack the methodology behind those corrections. However, the authors of the linked paper do not do this. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;The underlying data still supports global warming&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;As I mentioned, the thrust of the article is that corrections made to the calculation of global temperature averages from historical data are systematically biasing the data in favor of a linear warming trend. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The graph on page 11 of the paper provides a key piece of evidence. The blue line shows the original 1980 global historical temperature estimates, while the other lines show progressive refinements of that data through 2015. However, &lt;em&gt;the original line still shows increasing temperatures&lt;/em&gt;. Even only though 1980, the original line shows a temperature increase (albeit cyclical) of about 0.4 C over the hundred odd years of the chart. Even if the newer data's 'correction factor' of about +0.15 C (per chart IV-2) is taken out, the temperatures then rise another 0.4-0.15 = 0.25 C in the 30 years from 1980 to 2010.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short, the author's argument is that the global warming effect is being created by systematic biasing of an underlying data set; however, the underlying data set itself still shows a positive (if cyclical) warming trend of about 0.65 C over the past 130 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, even assuming the author's claims are correct that researchers are inappropriately manipulating data, the evidence still shows global warming over the past century plus. This suggests that if the authors are correct, perhaps the sensitivity of the climate models should be lowered; I don't see how it upends modern global warming theory or 'totally dismantles' anything.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Conclusion&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;I like to consider myself a skeptic, more or less. However, skepticism requires evidence, and there just isn't any evidence in this paper. Furthermore, even if the papers unsupported assertions turn out to be true, they don't provide an argument, much less any evidence, that carbon dioxide driven global warming is not happening. They don't provide any alternative theories to explain the magnitude of the warming that visible in the data, assuming that they are true in their claims of improper correction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, I would have to answer the question  'Could this study &quot;totally dismantle&quot; Global Warming claims?' with a categorical no. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="6703" LastEditDate="2017-07-13T20:01:28.913" LastActivityDate="2017-07-13T20:01:28.913" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10822" PostTypeId="2" ParentId="10820" CreationDate="2017-07-13T19:57:50.780" Score="2" Body="&lt;h1&gt;Ozone protects us by absorbing ultraviolet radiation&lt;/h1&gt;&#xA;&lt;p&gt;As shown in this &lt;a href=&quot;https://chemistry.stackexchange.com/questions/35734/what-property-allows-ozone-to-absorb-uv-light&quot;&gt;Chemistry.SE answer&lt;/a&gt;, ozone breaks upon incidence of various energies of UV radiation to form oxygen, which itself is somewhat effective at blocking UV radiation at other energies. THe key is that the incident UV radiation transfers its energy to the reaction products in order to break the bonds holding ozone (or oxygen) together.&lt;/p&gt;&#xA;&lt;p&gt;As opposed to protecting us from UV, the only way for ozone to protect us from global warming is for it to reflect the incident UV radiation back into space. That is not what it does. UV that enters the Earth's atmosphere and interacts with the ozone stays in the Earth's atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;Therefore, your question premise is flawed when you say &amp;quot;if ozone layers gets smaller, more UV radiation enters on Earth.&amp;quot; That is not true, because UV radiation that that enters the Earth will be absorbed by something, whether it is ozone or the rest of the atmosphere or the ground.&lt;/p&gt;&#xA;&lt;h1&gt;Global warming deals with infrared radiation&lt;/h1&gt;&#xA;&lt;p&gt;Furthermore, 'global warming' is primarily concerned with radiation heading &lt;em&gt;outwards&lt;/em&gt; in the infrared band. IR radiation emitted from the ground is blocked by CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; in the atmosphere and prevented from escaping into space. So the effect of ozone on UV radiation will have little to no effect on 'global warming'.&lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-07-13T19:57:50.780" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10823" PostTypeId="1" CreationDate="2017-07-14T00:26:58.617" Score="2" ViewCount="6522" Body="&lt;p&gt;Hydrocarbons have been found in great abundance &lt;a href=&quot;http://www.wnd.com/2005/12/33678/&quot; rel=&quot;nofollow noreferrer&quot;&gt;elsewhere in the solar system&lt;/a&gt; where there is unlikely to be evidence for life past or present.  No fossils involved.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Petroleum and natural gas wells that have gone dry 50 years ago, are found replenishing a fraction of their output.  No fossils involved.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Vast &lt;a href=&quot;https://gsw.silverchair-cdn.com/gsw/Content_public/Journal/geology/39/3/10.1130_focus032011.1/2/287.pdf?Expires=1500070338&amp;amp;Signature=BM8pz9XxjpBmQkcBK1re3emKnV5yV1XivHPpM2wczC-Tlfypz~jhlBPLSnSYWY3aAqtjFApaQIJK3p1z9kwuqTB6jsKS~1JrrWcHXcr3XkTEMNfq1kuRLtfVYPHX0QDxiSqmY8qouNl8vhH1OUs2inqn6r9nhgRPts-fu-KX4aBNXpl5eL3iJmjONPK96WLwnEJE2V1a-gXXDgwvL~CTiklKgVKIKQX0sftJao8uJdmfJhhkdqsRvA-iUi2GV8QbnVt8QPHzUGYxcXhJTnKXwkWKpqyjTwRSH~P6deT~T2i9SlW4ppi~d~uGyzKPZvgxURqRo4VnEDU8ulp~ppYTPw__&amp;amp;Key-Pair-Id=APKAIUCZBIA4LVPAVW3Q&quot; rel=&quot;nofollow noreferrer&quot;&gt;biomass of micro-organisms&lt;/a&gt; and extremophiles beneath earth surface estimated to be several times the size of the surface biomass found deriving their chemical energy for life from methane and oxygen pulled from sulfates and ferrous oxides.  The source of methane way too deep to come from fossils.  No fossils involved.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These recent findings and other evidence were foretold by the late scientist and researcher from Cornell, Thomas Gold, who authored &quot;&lt;a href=&quot;http://www.springer.com/us/book/9780387952536&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Deep Hot Biosphere, The Myth of Fossil Fuels&quot;&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;After seeing evidence of extremeophiles in relative abundance in even the &lt;a href=&quot;https://www.space.com/12491-worms-beneath-earth-surface-extremophiles.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;deepest of mines&lt;/a&gt;, Gold ties the sub-surface biosphere to the &quot;Deep Earth Gas theory&quot; to show a more plausible primordial explanation of hydrocarbon fuel formation than the generally accepted &quot;fossil&quot; theory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;He posits that &#xA;&quot;Hydrocarbons are not biology reworked by geology (as the traditional view would hold), but rather hydrocarbons are geology reworked by biology.&quot;  In other words, as in Saturn’s moon Titan and other hydrocarbon rich areas of the solar system, the source of hydrocarbons is &lt;strong&gt;primordial&lt;/strong&gt;; but as they upwell into earth’s outer crust microbial life uses it as energy source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While the details of the Deep Earth Gas Theory are beyond scope of elaboration in this question area, the main points which Dr. Gold supports, and provides evidence for are: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Hydrocarbons are primordial.&lt;/strong&gt; IOW, hydrocarbons like elsewhere in the solar systems are here since the planet's birth.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;The earth was subjected to only a partial melt.&lt;/strong&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Hydrocarbons are stable to great depth.&lt;/strong&gt;  High pressure greatly stabilizes hydrocarbons against thermal dissociation.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Rock at depth contains pores.&lt;/strong&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Primordial hydrocarbons are still upwelling from the deep earth.&lt;/strong&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;some sub-points worthy of mention:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It more adequately explains why Helium is only present in the earth at any mine-able quantity in natural gas.   There are no pure Helium wells.  Why the strong association of hydrocarbons with Helium, an inert gas that can have no chemical interactions with fossil organic materials or with hydrocarbons?  This is known to geologists as the &quot;Petroleum Paradox&quot; and cannot be explained at all by a sedimentary origin of hydrocarbons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The presently accepted theory of fossil fuels is that the hydrocarbons formed from the decayed remains of ancient organic matter (fossils) that somehow sank down into the deep earth and got trapped in sedimentary rock formations where increased pressures assisted in converting the organic material over time to hydrocarbons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Well, hydrocarbons are found in depths where no surface life remains could have possibly geologically submerged to.  The physics of how the ancient organic materials or the resulting hydrocarbons sank deep into the earth have yet to be explained.  Also, hydrocarbons have been found in igneous rock formations, which the accepted surface to sediment theory cannot explain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can we still say that fossil fuels are really from fossils?&lt;/p&gt;&#xA;" OwnerUserId="8212" LastEditorUserId="8212" LastEditDate="2017-07-18T17:08:15.777" LastActivityDate="2022-10-25T14:23:59.013" Title="Are fossil fuels really formed from fossils?" Tags="|geochemistry|sedimentology|igneous|fossil-fuel|methane|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10827" PostTypeId="2" ParentId="10823" CreationDate="2017-07-14T11:11:28.143" Score="15" Body="&lt;p&gt;Let's look at this. A very large number of points for one question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, the solar system. We do not see any hydrocarbons in the inner solar system (Mercury to Mars). This is because in this region of the solar system, dissociation by solar UV rapidly destroys primordial hydrocarbons.  This effect is much weaker further out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oil well 'replenishment' will happen to some degree over several decades, just from internal migration of oil. &lt;a href=&quot;http://wiki.aapg.org/Reserves_estimation&quot; rel=&quot;noreferrer&quot;&gt;Typically only a certain percentage of oil in place is recovered&lt;/a&gt;, with the rest left in isolated pockets by the water flood. Give it a few decades and these oil pockets will tend to remigrate and link up, giving the appearance of replenishment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not sure what you comment of &lt;em&gt;The source of methane way too deep to come from fossils. No fossils involved.&lt;/em&gt;. That's an unreferenced assertion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Helium is present in Natural Gas as a result of accumulation of alpha-decay particles from radioactive isotopes; we can see this from the massive enrichment of Helium-4 over &lt;a href=&quot;https://en.wikipedia.org/wiki/Helium-3&quot; rel=&quot;noreferrer&quot;&gt;Helium-3&lt;/a&gt;. It's not a paradox; geological structures that can trap methane will also trap helium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The current theory behind &lt;a href=&quot;https://en.wikipedia.org/wiki/Petroleum_geology&quot; rel=&quot;noreferrer&quot;&gt;petroleum geology&lt;/a&gt; is that source rocks with a high organic content (often containing biological hydrocarbons from algae and leaf waxes) are buried in sedimentary basins; at temperatures around 100-150 degrees C this kerogen breaks down to form crude oils (this is verified in the lab). Oil then migrates out of this source rock; if it encounters a trapping geological structure, which need not be sedimentary, then it accumulates as an oil deposit. Gas is similar, with a wider range of source rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The physics of how this happens are &lt;a href=&quot;http://wiki.aapg.org/Plate_tectonics_and_basin_formation&quot; rel=&quot;noreferrer&quot;&gt;well known and established&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would also note that we don't see hydrocarbons coming out of mantle-derived volcanoes such as at Hawaii. This is a major problem for any theory of primordial hydrocarbons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Additional Points&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, it would be nice if you provided references rather than a link to a book to buy. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;If hydrocarbons were primordial, then we would expect to find them mostly in areas where the mantle or mantle taps reach the surface - mid ocean ridges, and ocean island volcanoes. We don't. The major oil fields are located in continental extensional basin settings. &lt;/li&gt;&#xA;&lt;li&gt;There is &lt;a href=&quot;http://jgs.geoscienceworld.org/content/146/1/147&quot; rel=&quot;noreferrer&quot;&gt;plenty of evidence&lt;/a&gt; for mantle outgassing - including all volatile species such as hydrocarbons - in the first few hundred million years. Furthermore, on geological timescales the mantle is still undergoing &lt;a href=&quot;https://www.geophysik.uni-muenchen.de/research/geodynamics/mantle-convection&quot; rel=&quot;noreferrer&quot;&gt;vigorous convection&lt;/a&gt; and can be considered liquid.&lt;/li&gt;&#xA;&lt;li&gt;Is irrelevant.&lt;/li&gt;&#xA;&lt;li&gt;This is simply wrong, if referring to pores that can offer any support against pressure. The crust becomes ductile at about 10-15km, and the mantle at 60+km, meaning that conventional porosity cannot exist. &lt;/li&gt;&#xA;&lt;li&gt;See (1). For the Earth, outgassing was essentially completed billions of years ago, as we can see from isotopic evidence (and I suspect that the &lt;a href=&quot;https://en.wikipedia.org/wiki/Giant-impact_hypothesis&quot; rel=&quot;noreferrer&quot;&gt;moon-forming impact&lt;/a&gt; didn't help).&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="8217" LastEditorUserId="8217" LastEditDate="2017-07-19T08:27:15.103" LastActivityDate="2017-07-19T08:27:15.103" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10829" PostTypeId="2" ParentId="10735" CreationDate="2017-07-15T01:53:34.537" Score="2" Body="&lt;p&gt;A good rule of thumb for down-scaling with WRF is not to interpolate down more than 3 or 4 times; with 3 being the standard recommendation. So while 18 km is probably overkill for an outer domain (this is a personal opinion, there are some operational models like HWRF that start at 18km), 2km would definitely be too fine for a parent domain. The main reason for this is the boundary conditions: your wrfbdy_d01 file is interpolated from the original data down to your model's resolution, so for a 2km domain you will be constantly having very low resolution features imposed upon your boundaries, which will cause fairly unphysical conditions at the boundaries throughout your forecast period. By having a wider, lower-resolution &quot;buffer&quot; domain between you and the outer boundary conditions you avoid unphysical artifacts entering your domain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are 5 overlap gridpoints at the edge of each domain, so your inner domain should be at least 5 (outer) gridpoints away from the outer domain.&lt;/p&gt;&#xA;" OwnerUserId="6601" LastActivityDate="2017-07-15T01:53:34.537" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10830" PostTypeId="1" CreationDate="2017-07-15T05:19:49.047" Score="0" ViewCount="1466" Body="&lt;p&gt;My question is basically the title. Ignoring most of the feasibility of the enormous engineering and earthmoving requirements (I guess I mean to say, given an unlimited budget) in very hot areas, would this effectively solve the problem of sea level rise as a problem? If not, what am I missing? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not sure if this question is within the scope of this board, but I like pushing the boundaries :)&lt;/p&gt;&#xA;" OwnerUserId="4878" LastActivityDate="2017-07-16T03:57:36.960" Title="Hypothetically, would digging a big trench from the ocean and flooding desert areas be a bad solution to combatting sea level rise?" Tags="|climate-change|sea-level|desert|" AnswerCount="1" CommentCount="7" ClosedDate="2017-07-16T07:59:52.823" ContentLicense="CC BY-SA 3.0" />
  <row Id="10832" PostTypeId="2" ParentId="10830" CreationDate="2017-07-15T17:31:29.143" Score="5" Body="&lt;p&gt;Yes, it would be a bad solution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Aside from the construction and maintenance cost, the impact to the populations affected, and the impact on the environment around the destination, the benefits would be minimal, as roughly calculated in the answer to &lt;a href=&quot;https://gis.stackexchange.com/questions/65206/volume-of-land-below-sea-level&quot;&gt;Volume of Land Below Sea Level&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;So to reduce the sea level by 1m the total area of these depressions&#xA;  needs to be around 5,000,000 km^2. This is around half the total land&#xA;  area of the USA. I don't have the figures to hand but given that these&#xA;  area would probably all fit into an area considerably smaller than&#xA;  Texas - I estimate that flooding land which is below sea level will&#xA;  reduce the sea level by exactly 'not very much at all' (give or take a&#xA;  millimeter - and very much less than 1m in any event).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There is also a rate of flow issue. You basically want to create rivers flowing inland at a rate to offset or reverse sea level rise, which means the flow rate of those rivers has to approach the volume of global sea rise. Global sea level is rising by an average of about 3.4mm per year, or 1,230 cubic kilometers per year &lt;a href=&quot;https://climate.nasa.gov/vital-signs/sea-level/&quot; rel=&quot;nofollow noreferrer&quot;&gt;according to NASA&lt;/a&gt; (and the rate is increasing). That amount is about &lt;a href=&quot;https://en.wikipedia.org/wiki/Congo_River&quot; rel=&quot;nofollow noreferrer&quot;&gt;the flow of the Congo River&lt;/a&gt; (the second largest river in the world) or roughly &lt;a href=&quot;https://en.wikipedia.org/wiki/Amazon_River&quot; rel=&quot;nofollow noreferrer&quot;&gt;19 percent of the flow of the Amazon River&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fed by gravity, these are among the widest and deepest rivers of the world; if you're going to move that volume of water, you need to build channels to each basin with a net flow similar to that capacity, with that gradient, that won't leach saltwater into the groundwater of surrounding communities. (The engineering issues likely pale in comparison to the political challenges.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And keep in mind that transferring water inland is only a temporary solution. Water evaporates and by spreading water over a larger area you're increasing its surface area; Death Valley has an evaporation rate of &lt;a href=&quot;https://wrcc.dri.edu/htmlfiles/westevap.final.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;140 inches or 3.5 meters per year&lt;/a&gt;. (In Southern California, &lt;a href=&quot;https://en.wikipedia.org/wiki/Salton_Sea&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Salton Sea&lt;/a&gt; is drying out and causing a variety of salinity and dust issues due to lack of inflows.) So you're transferring ~60-degree seawater into a salt pan where it's going to heat up and evaporate and leave behind a toxic brine, then fall or flow back into the ocean, contributing in some small way to the thermal expansion of the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Also, the net volume of CO2 released by building and maintaining these massive projects would also contribute to global warming in some non-negligible way.)&lt;/p&gt;&#xA;" OwnerUserId="7314" LastEditorUserId="7314" LastEditDate="2017-07-16T03:57:36.960" LastActivityDate="2017-07-16T03:57:36.960" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10834" PostTypeId="1" CreationDate="2017-07-15T22:55:27.957" Score="0" ViewCount="75" Body="&lt;p&gt;Meteorologists often say that it’s difficult to attribute any individual weather event to climate change, but I’m wondering, &lt;strong&gt;do meteorologists or weather services study or publish derivative climate data&lt;/strong&gt;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, “this is the first time temperatures have reached 30°&amp;#160;C for seven consecutive days at this location” or maybe “this is the first eleven‑month period without snowfall at this location”.&lt;/p&gt;&#xA;" OwnerUserId="7842" LastActivityDate="2017-07-16T20:43:14.310" Title="Are there sources that offer derivative climate change data?" Tags="|meteorology|extreme-weather|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10836" PostTypeId="1" CreationDate="2017-07-16T09:35:54.543" Score="10" ViewCount="154" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Seasonal_flows_on_warm_Martian_slopes&quot; rel=&quot;nofollow noreferrer&quot;&gt;Recurring Slope Lineae (RSL)&lt;/a&gt; on Mars are suggested to be water that seasonally melts from underground ice and sublimates through the sand and dust to darken the surface. Slowly flowing downhill to form the lines.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not sure it has been determined that it is water and not CO2. But assuming that it is water (brine), what are the nearest analogues on Earth to a Martian RSL environment? Are there any RSL's on Earth? What kind of life thrives in them?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://thumbs.gfycat.com/MadeupShamelessIndianjackal-mobile.mp4&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here is a brief video&lt;/a&gt; of how they change seasonally.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/X24Ld.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/X24Ld.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3033" LastEditorUserId="595" LastEditDate="2017-07-24T06:19:17.523" LastActivityDate="2019-05-25T20:17:23.713" Title="What are the most similar Earth analogues to Mars' seasonally recurring slope linea?" Tags="|seasons|mars|astrobiology|underground-water|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10837" PostTypeId="1" CreationDate="2017-07-16T13:05:09.123" Score="6" ViewCount="1237" Body="&lt;p&gt;Consider the example of the Larsen Ice Shelf. Ice platforms are attached to glaciers such that they prevent surrounding warm air from directly melting the glaciers.  This is an important aspect of ice platforms. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the mechanisms of glacier movement?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When we talk about glacier movement, do we consider advance and retreat due to melting and snow deposition, or is the study of glacier movement more about the fluid sheet underneath the glacier that comes in contact with the rocks, which allows the glacier to move downhill?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With this second type of movement, glaciers can separate.  So is it possible for Antarctica to separate and disappear?&lt;/p&gt;&#xA;" OwnerUserId="5851" LastEditorUserId="11908" LastEditDate="2019-04-06T22:31:11.687" LastActivityDate="2019-04-06T22:31:11.687" Title="How do glaciers move? Could Antarctica be separated?" Tags="|glaciology|antarctic|antarctica|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10838" PostTypeId="1" AcceptedAnswerId="11890" CreationDate="2017-07-16T16:31:09.003" Score="2" ViewCount="56" Body="&lt;p&gt;Chicxulub crater is the third largest crater on earth, which is said to have produced the KT boundary.   What is the sediment layer produced by the 1st and 2nd largest craters?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, there many craters before and after Chicxulub was created, but the KT boundary is the only one commonly mentioned…why? &lt;/p&gt;&#xA;" OwnerUserId="9596" LastEditorUserId="725" LastEditDate="2017-07-22T06:56:55.343" LastActivityDate="2017-08-21T07:41:52.600" Title="Sediment boundarys produced by largest meteors? Vredefort, Sudbury and Chicxulub" Tags="|earth-history|meteorite|natural-disasters|impacts|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10839" PostTypeId="2" ParentId="10834" CreationDate="2017-07-16T20:43:14.310" Score="2" Body="&lt;p&gt;Since you comment on statistics provided during sport events, I should point out that this method is not scientifically sound. The reason is that for any given data you will find something that will make this dataset unique or &quot;the first of this kind in recorded history&quot;. For a light take on this, refer to &lt;a href=&quot;https://xkcd.com/1122/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this XKCD comic&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is methodically required is that &lt;em&gt;first&lt;/em&gt; the criteria are defined and only then the data are evaluated. Weather services will typically publish things such as&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Ranking average temperature within a calendar month (e.g. this July was the third hottest in recorded history (example is purely fictional)) at a certain location&lt;/li&gt;&#xA;&lt;li&gt;Ranking of daily minimum/maximum temperature at some location (e.g. this was the coldest day ever measured)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Details on this will vary from country to country. There is also a wide range of measurement data or derived data for experts to analyze. Also, weather services will engage in studies about the impact of climate change.&lt;/p&gt;&#xA;" OwnerUserId="681" LastActivityDate="2017-07-16T20:43:14.310" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10842" PostTypeId="2" ParentId="10837" CreationDate="2017-07-17T01:02:06.607" Score="6" Body="&lt;p&gt;Glaciology is a large field of research, and I cannot include all aspects in a short answer. I'll try to give some concepts that can help you in your understanding of the cryosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Glaciers are, per definition, moving &lt;strong&gt;due to gravity&lt;/strong&gt; towards lower altitudes. There are some exceptions, e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Rock_glacier&quot; rel=&quot;noreferrer&quot;&gt;rock glaciers&lt;/a&gt; are the stagnant remain of a moving glacier. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Large bodies of ice are called either ice caps (if smaller than 50,000 km$^2$) or ice sheets (if larger). Today, we only have the &lt;a href=&quot;https://en.wikipedia.org/wiki/Antarctic_ice_sheet&quot; rel=&quot;noreferrer&quot;&gt;Antarctic ice sheet&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Greenland_ice_sheet&quot; rel=&quot;noreferrer&quot;&gt;Greenland&lt;/a&gt;, but during times of larger glaciation, large parts of the Northern Hemisphere were covered. Within the ice sheets, fast flowing areas are referred to as &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_glaciers_in_the_Antarctic&quot; rel=&quot;noreferrer&quot;&gt;glaciers&lt;/a&gt;. Where those areas are formed depends on many parameters such as the mass balance, the basal melting, the topography, etc. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the glacier or ice sheet reaches the ocean, it &lt;a href=&quot;http://web.mit.edu/slazzari/www/3.-why-does-ice-float-on-water.html&quot; rel=&quot;noreferrer&quot;&gt;becomes buoyant&lt;/a&gt;. For larger glaciers, the section near the coast remains bulky enough to remain in contact with the ground.  The point of extent where the ocean reaches under the ice is called the &lt;a href=&quot;http://www.antarcticglaciers.org/glaciers-and-climate/ice-ocean-interactions/grounding-lines/&quot; rel=&quot;noreferrer&quot;&gt;grounding line&lt;/a&gt; - a subglacial beach, if you like. &#xA;As it's floating, tidal variations moving the ice sheets help it to break up, but in some cases, depending on thickness and topography, it can float in a rather uniform shape which we call an ice-shelf. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same way as rivers and lakes are formed as rainwater floats towards the oceans, ice sheets and ice caps are formed as snow falls in cold areas, where it doesn't get warm enough to melt during the summer. As the snow accumulates it forms &lt;a href=&quot;https://en.wikipedia.org/wiki/Firn&quot; rel=&quot;noreferrer&quot;&gt;firn&lt;/a&gt; and later ice. The ice starts moving as the gravity and shear forces make it unstable. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Eventually the ice will melt, either on the surface due to warm air, e.g. during summer months, or in the oceans as it calves off into icebergs and is warmed by the ocean. Glaciers can also melt on the base due to heat flux from the Earth beneath or due to pressure. In this way, subglacial lakes are formed under the ice. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Large parts of Antarctica are &lt;a href=&quot;http://www.the-cryosphere.net/7/375/2013/tc-7-375-2013.pdf&quot; rel=&quot;noreferrer&quot;&gt;situated below sea level&lt;/a&gt;. Partly this is due to the intensive erosion of fast moving ice, but the main reason is that the weight of the ice pushes down the crust into the mantle. If the ice sheet melts, the mass decreases and the land under it will &lt;a href=&quot;https://en.wikipedia.org/wiki/Post-glacial_rebound&quot; rel=&quot;noreferrer&quot;&gt;rebound&lt;/a&gt;. This happens almost on a human timeline. Some areas, such as Hudson Bay, Scandinavia, and the Antarctic Peninsula, have a fast uplift making sea into land. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7kZn9.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7kZn9.jpg&quot; alt=&quot;Quantarctica&quot;&gt;&lt;/a&gt;&#xA;&lt;em&gt;Maps from &lt;a href=&quot;http://quantarctica.npolar.no/&quot; rel=&quot;noreferrer&quot;&gt;Quantarctica&lt;/a&gt;. 1: Ice flow velocity. 2: The topography under the ice. 3: Geoid height (not so relevant for your question). 4: Snow accumulation and blue (=old, hard) ice.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I've suggested &lt;a href=&quot;https://earthscience.stackexchange.com/questions/10761/considering-how-old-the-antarctic-ice-cover-is-why-isnt-it-much-thicker/10764#10764&quot;&gt;before&lt;/a&gt;, I recommend you to download the &lt;a href=&quot;http://quantarctica.npolar.no/&quot; rel=&quot;noreferrer&quot;&gt;Quantarctica&lt;/a&gt; package. It's rather big but free and easy to use. You can investigate how the ice flows are forming the ice sheet and how the bed map looks under. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The large chunk of Larsen C Ice Shelf that just broke off, doesn't directly reshape the Antarctic continent or cause any change in global sea level, as it was already floating. However, if the ice shelf becomes more unstable, it can affect the ice sheet left trailing it and the flow pattern of the glaciers, and that would have a large impact on most human activities - and beyond. &lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="6298" LastEditDate="2018-01-31T06:14:07.783" LastActivityDate="2018-01-31T06:14:07.783" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10844" PostTypeId="1" AcceptedAnswerId="10846" CreationDate="2017-07-17T05:38:59.747" Score="1" ViewCount="125" Body="&lt;p&gt;I have a data set which contains NDVI (Normalized Difference Vegetation Index) values of four directions (NE, NW, SE, SW). Now, I would like to have single value which considers all 4 directions. Is it fine to take an average or is there any other metric that can be considered? Any suggestions on which is the appropriate method? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/glEPA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/glEPA.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More information on the data source:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This data is from a competition from &lt;a href=&quot;https://www.drivendata.org/competitions/44/dengai-predicting-disease-spread/page/82/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Driven data&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;NDVI is &#xA;Satellite vegetation - Normalized difference vegetation index (NDVI) - NOAA's CDR Normalized Difference Vegetation Index (0.5x0.5 degree scale) measurements&lt;/p&gt;&#xA;" OwnerUserId="9601" LastEditorUserId="9601" LastEditDate="2017-07-17T09:39:25.663" LastActivityDate="2017-07-17T10:10:56.480" Title="How to get single value of NDVI value from four different directions?" Tags="|meteorology|remote-sensing|vegetation|ndvi|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10845" PostTypeId="2" ParentId="10761" CreationDate="2017-07-17T05:41:18.480" Score="4" Body="&lt;p&gt;An interesting point to consider comes from your assumption of a constant rate of precipitation. Many earth system processes have non-trivial stochastic variations (or high-dimensional chaos). Consider the conservation of mass for ice:&lt;/p&gt;&#xA;&lt;p&gt;change in ice thickness = (precipitation, mass in) - (pick your favorite process, mass out).&lt;/p&gt;&#xA;&lt;p&gt;Both (mass in) and (mass out) processes have significant random variability, both in space and time. When you integrate a random variable, a special thing happens: you get a random walk. The figure below shows 5 random walks&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/suiBL.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/suiBL.png&quot; alt=&quot;random walk&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;sub&gt;(source: &lt;a href=&quot;https://people.sc.fsu.edu/%7Ejburkardt/m_src/random_walk_1d_simulation/walk_5_steps_500_plot.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;jburkardt at people.sc.fsu.edu&lt;/a&gt;)&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;Notice how several different random walks spread apart with time? A random walk has the property that, the standard deviation of all walks together, grows with the square root of time. As in, the spread of all positions at a given point in time, grows proportionally to the square root of time. If the random walk wasn't random, but was constant instead, you would have a straight line (this is the case you described).&lt;/p&gt;&#xA;&lt;p&gt;So here is the first point to be made: a constant rate of precipitation leads to a linear increase in ice thickness, growing without bound. By adding in some randomness to approximate nature better, the rate at which the ice thickness grows is fractional with time rather than linear. A true random walk is still unbounded, and so there are clearly some negative feedback mechanisms at play as mentioned in the previous posts.&lt;/p&gt;&#xA;&lt;p&gt;Second point (actually answering your question). As this is a 2d surface, you could model glacial topography as 2D random field. In the absence of forcing, the dynamics of glacial topography is effectively a diffusion equation. A randomly forced diffusive surface has a natural (or internal) cutoff length scale, or scale above which ice won't grow. However, this cutoff scale would be a function of ice surface diffusivity, rather than a feedback mechanism between the system and forcing. So this is all to say, it could be a feedback mechanism, or it could be set internally by the material properties of the system. I'll look and see if anyone has written papers on this yet.&lt;/p&gt;&#xA;&lt;p&gt;The figure below shows an example of a 2D random field. I don't know how exactly it was generated, but it's basically the kind of solution you would get from a 2D diffusion equation with random forcing.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/veC49.png&quot; alt=&quot;2d random noise&quot; /&gt;&lt;/p&gt;&#xA;" OwnerUserId="6221" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-07-18T20:18:38.953" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="10846" PostTypeId="2" ParentId="10844" CreationDate="2017-07-17T10:10:56.480" Score="1" Body="&lt;p&gt;After given some information about the data source I have a simple answer. Since the underscores SW etc. represent the four pixels around the city center and all the pixels cover the same physical area, taking a mean of the values will represent the average NDVI of the total area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is all about what you will do with the NDVI data. E.g. if something interesting occurs when somewhere near the center vegetation amounts are low (high), then the minimum (maximum) of these might provide you with more useful predictor.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastActivityDate="2017-07-17T10:10:56.480" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10850" PostTypeId="1" AcceptedAnswerId="10853" CreationDate="2017-07-17T19:31:09.663" Score="4" ViewCount="79" Body="&lt;p&gt;I am looking for a (small) data set of weather observations for a few (say 5-20) weather stations in the US, with observations of precipitation, temperature and wind speed for the year 2016. The data should be freely available and downloadable - and, should be allowed to be re-distributed to third parties, since I would like to use it as an example data set in an R package to demonstrate some methodology I have implemented.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there such a data set?&lt;/p&gt;&#xA;" OwnerUserId="5471" LastActivityDate="2017-07-17T21:28:13.777" Title="Freely available and re-distributable weather observations over the US?" Tags="|meteorology|weather-forecasting|open-data|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="10851" PostTypeId="2" ParentId="10770" CreationDate="2017-07-17T19:54:50.213" Score="5" Body="&lt;p&gt;A few thoughts - assuming like you say that the aqua-planet is the same size as earth, and all else being equal, it's best to consider the two major classes of waves:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Nondispersive wind generated waves:&lt;/strong&gt; Here the maximum wave height is a function of wind speed (fetch). However, wind speed in general is not a function of wave height (unless you invoke concepts like walker-circulation from ENSO, but you wouldn't get ENSO since there are no continental boundaries). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The relationship between maximum wave height and fetch in deep water, can be described empirically as $$H_{max}=0.332 \sqrt{F}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So this all goes to say that it is impossible to determine $H_{max}$ without knowing something about the atmosphere dynamics. If you assume that the atmospheric dynamics are the same as on earth (in terms of storm statistics), then this little empirical relation would suggest wind generated wave heights should be no different for an equally sized aqua-planet. Larger planets &lt;em&gt;do&lt;/em&gt; however have larger storms...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Eddies and planetary waves&lt;/strong&gt; Eddies are waves, yet quite different from wind generated waves. While they certainly don't reach the impressive heights of wind-generated waves, their wavelengths are several orders of magnitude larger. And so technically, you could say they are in fact &quot;bigger&quot; waves. Along with eddies, there &lt;em&gt;planetary waves&lt;/em&gt; such as Rossby waves and Kelvin waves. All these eddies and planetary waves are limited in size by the Rossby radius of deformation. Which is to say, their maximum size is effectively limited by the curvature of the earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Upshot&lt;/strong&gt; To get larger wind generated waves, you need larger storms. Therefore you need a larger planet (e.g. great red spot on jupiter). To get larger planetary waves and eddies, you also need a larger planet! The reason that larger planets have both larger storms &lt;em&gt;and&lt;/em&gt; larger planetary wave/eddies is the same ~ which is that the rossby radius is bigger for a bigger planet. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might be interested to check out something called the &quot;aqua planet experiment&quot; project. These are general circulation models run on a hypothetical planet with no continent, they're all just atmosphere and ocean. The image below is cloud cover output from an aqua-planet simulation.&#xA;&lt;img src=&quot;https://lh3.googleusercontent.com/-Bk5C3dex8ow/U7eyCVVLl4I/AAAAAAAAxjc/vOCJyvpyjNw/w500-h375-p/aquaplanet_NICAM.gif&quot; alt=&quot;aqua planet&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="6221" LastEditorUserId="6221" LastEditDate="2017-07-17T20:04:49.610" LastActivityDate="2017-07-17T20:04:49.610" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10852" PostTypeId="1" CreationDate="2017-07-17T21:24:38.307" Score="3" ViewCount="31" Body="&lt;p&gt;So i know that there are diurnal patterns for virtual potential temperature that can be described conceptually (such as $\frac{\partial \theta_v}{\partial z}\approx 0$ in the mixed layer and $\frac{\partial \theta_v}{\partial z} &amp;gt;0$ in the entrainment zone). I know there are similar relationships seen for moisture. Is there a similar concept for $\ce{[O_3]}$?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, is $\frac{\partial \ce{[O_3]}}{\partial z}&amp;gt;0$, $\approx0$ or $&amp;lt;0$ in the entrainment zone? What about the residual layer? Nocturnal inversion? And so on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References would be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-07-17T21:24:38.307" Title="Is there a conceptual diurnal model for ozone profile?" Tags="|atmospheric-chemistry|ozone|planetary-boundary-layer|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10853" PostTypeId="2" ParentId="10850" CreationDate="2017-07-17T21:28:13.777" Score="7" Body="&lt;p&gt;Such a dataset can be found via the NCDC. &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/land-based-station-data/land-based-datasets&quot; rel=&quot;noreferrer&quot;&gt;Here&lt;/a&gt; is the main gateway. My 'go to' place for high temporal resolution data from NCDC is the &lt;a href=&quot;ftp://ftp.ncdc.noaa.gov/pub/data/asos-fivemin/6401-2016/&quot; rel=&quot;noreferrer&quot;&gt;5-minute ASOS data&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-07-17T21:28:13.777" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="10854" PostTypeId="1" CreationDate="2017-07-18T03:13:53.843" Score="0" ViewCount="115" Body="&lt;p&gt;What counter heating effects are taken into account in popular climate change models?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are things such as the cooling effect of polar ice melt and the desalination from ice melt rivers taken into account?&lt;/p&gt;&#xA;" OwnerUserId="9606" LastActivityDate="2017-07-18T22:03:22.417" Title="Climate change model" Tags="|meteorology|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="10855" PostTypeId="1" AcceptedAnswerId="25266" CreationDate="2017-07-18T09:53:27.737" Score="6" ViewCount="118" Body="&lt;p&gt;I have read in environmental science textbooks that aluminum can acidify soil, whereas metals such as sodium, calcium, magnesium, and potassium can alkalinize soils.  I understand that Al&lt;sup&gt;3+&lt;/sup&gt; can hydrolyze water to form 3H&lt;sup&gt;+&lt;/sup&gt; and lower pH.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why are alkali and alkaline earth metals described as alkalinizing soils?  I understand that the neutral elemental forms of these metals (alkali, alkaline earth) react with water to form OH&lt;sup&gt;-&lt;/sup&gt;, but the prevailing cation-form is much less reactive, except that it might precipitate with OH&lt;sup&gt;-&lt;/sup&gt; from water self-ionization, and shift the equilibrium towards more H&lt;sup&gt;+&lt;/sup&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also know that some of these cations are commonly found in minerals with carbonate and silicate that can lead to OH&lt;sup&gt;-&lt;/sup&gt;, but this seems to driven by the counter-ion, not the metal cation.&lt;/p&gt;&#xA;" OwnerUserId="7465" LastActivityDate="2023-06-13T02:06:15.223" Title="Soil metals acids and bases" Tags="|soil|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10858" PostTypeId="2" ParentId="10854" CreationDate="2017-07-18T17:57:01.790" Score="3" Body="&lt;p&gt;Both are relatively small secondary effects on global temperature, but at the same time, both are worth studying.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ice acts like a heat sponge.   It takes heat to melt ice (that's kinda obvious) and less obvious, forming ice releases heat.   Large blocks of ice cool the air when it's above freezing and warm the air when it's below.   Even as ice changes from solid to liquid, without changing it's temperature, the energy change is significant.   This is called it's &lt;a href=&quot;https://www.britannica.com/science/latent-heat&quot; rel=&quot;nofollow noreferrer&quot;&gt;latent heat of fusion&lt;/a&gt; or LHF.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By &lt;a href=&quot;https://www.skepticalscience.com/Where-is-global-warming-going.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; about 2% of the trapped heat goes into melting ice.   A 2% variation on heat that would otherwise, warm the air or oceans or escape into space is almost small enough to ignore, but the effect grows much larger locally near glaciers (perhaps as high as 25%, but the source I found for that isn't one I'd call credible), but certainly, the effect is significantly higher than 2% in the arctic and antarctic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Latent heat of fusion is also important in calculations for the total energy balance and here's an &lt;a href=&quot;https://www.ipcc.ch/publications_and_data/ar4/wg1/en/ch5s5-2-2-3.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;article from IPCC AR4&lt;/a&gt; that discusses LHF.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As pointed out in the comments, melting sea ice also changes ocean albedo and can lead to a rather quick change in absorbed heat and a reduction in the light reflected back into space.  This also happens on land, mostly snow cover, (as glaciers melt too slowly for that kind of year to year effect), but I don't think that's what the question is asking.   &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The 2nd part, the change in salinity is (to my knowledge, and I invite correction from anyone who studies this professionally), but from what I've read, it's much more complicated to model than LHF.   It's certainly something that researchers are aware of, both the warming arctic and changes in salinity might effect ocean currents.   Unlike air, where temperature drives density and that leads to low and high pressure and updrafts and basically, weather, oceans have two factors that can effect water density - temperature and salinity.   Warm water is lighter than cold water, but lower salinity water is also lighter than warmer, more salty water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Small changes in salinity in ocean surface water doesn't have any real effect on temperature directly, but the effect on ocean currents is worth studying because changes in ocean currents can effect temperature significantly, certainly on a local scale, and globally too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Modelling this, like modeling the rate of future glacial melt, may be close to impossible and when it's written about, it can sound more alarmist than science, so it's a subject that has 2 key problems, difficult to predict (even in the hard to predict climate change models the effect of salinity changes on ocean currents are especially tricky), and it's the kind of thing that might invite shouts from the other side, like &lt;a href=&quot;https://en.wikipedia.org/wiki/Wies%C5%82aw_Mas%C5%82owski&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wiesław Masłowski's&lt;/a&gt; infamous study that suggested the arctic might be ice-free by 2013.   He was a graduate student, not a climate scientist and his was a good study and preliminary.  It should have been subject to peer review, instead, (in part because Al Gore used his study in a speech), it became a famous example to alarmism and was subject to much ridicule that persists to this day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Scientists are certainly aware of the possible effects of salinity changes and the effect that might have on ocean currents, but it's very difficult to model and mostly written about observed effects in the present, and mostly not written regarding future forecasts.   Predictions like &quot;the Atlantic current could shut down&quot; may be based in science, but low probability predictions like that tend to invite criticism.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fresh water/ice melt is discussed in &lt;a href=&quot;https://en.wikipedia.org/wiki/Shutdown_of_thermohaline_circulation#Thermohaline_circulation_and_fresh_water&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia here&lt;/a&gt; and here's an article where the opposite is happening.   As arctic sea ice recedes, the lighter, less salty water on top isn't present as much as it used to be and the arctic-ocean stratification is going away.   &lt;a href=&quot;https://www.washingtonpost.com/news/energy-environment/wp/2017/04/06/scientists-say-the-unique-arctic-ocean-is-being-transformed-before-our-eyes/?utm_term=.c7b25c86e288&quot; rel=&quot;nofollow noreferrer&quot;&gt;Article on that here.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's also worth noting that glacier fed rivers will affect the ecosystem down-river, putting less or more water into the environment leading to less or more greening and less or more water evaporating off the river into the atmosphere.   It's more common for rivers to be fed by snow melt than glacial melt, but the glacial melt should be studied too.   Changes in greening down-river and in atmospheric water vapor also effect climate, so, as someone said in the comments, there are a lot of moving parts to the climate picture.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Generally speaking, scientists are aware of all of this and as much as possible, study it and include it in models.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2017-07-18T22:03:22.417" LastActivityDate="2017-07-18T22:03:22.417" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10859" PostTypeId="1" CreationDate="2017-07-19T04:03:30.397" Score="5" ViewCount="13864" Body="&lt;p&gt;Is it true that a coastal area is less likely to see snow compared with inland area nearby? If so, what are the reasons?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="543" LastEditDate="2017-07-20T04:15:56.377" LastActivityDate="2017-07-25T23:36:43.743" Title="Is snow less likely to appear at a coastal area?" Tags="|snow|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10860" PostTypeId="1" CreationDate="2017-07-19T11:48:31.100" Score="9" ViewCount="482" Body="&lt;p&gt;Every mineral has it's own internal building scheme, a lattice on which it's atoms lie. Mathematically, this can be described by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Space_group&quot; rel=&quot;noreferrer&quot;&gt;space group&lt;/a&gt; of the mineral. From mathematical considerations it's known that there are exactly 230 symmetry groups which can occur as the space group of a mineral. Now my question is: Is each of the 230 space groups realized as the symmetry group of a mineral?&lt;/p&gt;&#xA;" OwnerUserId="9612" LastActivityDate="2017-09-22T12:05:40.793" Title="Is every space group realized by some mineral?" Tags="|crystallography|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10861" PostTypeId="2" ParentId="10859" CreationDate="2017-07-19T12:44:53.773" Score="3" Body="&lt;p&gt;I don't know if someone has conducted statistical research on this. It certainly depends on the situation. Here are some situations:&lt;/p&gt;&#xA;&lt;h1&gt;More snow in coast&lt;/h1&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Like @gerrit commented, elevation increases precipitation as air is forced to lift up and thus cools condensing water vapor -&amp;gt; rain/snow. This is true when predominant winds are from the sea.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Lake-effect_snow&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake-effect snow&lt;/a&gt; situations&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;h1&gt;Less snow in coast&lt;/h1&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The air temperatures are affected by nearby bodies of water so situations where temperatures are freezing, but the sea isn't frozen yet will keep the coastal temperatures higher. Thus melting falling and fallen snow faster than in inland.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6465" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-07-19T12:53:08.497" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10862" PostTypeId="1" CreationDate="2017-07-19T17:24:21.607" Score="1" ViewCount="11836" Body="&lt;p&gt;A few months ago I was in car and noticed moon. You could see bottom half (in crescent shape) but not top half.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How is this possible to look up into night sky and see only bottom half of moon?&lt;/p&gt;&#xA;" OwnerUserId="9618" LastActivityDate="2019-10-03T12:36:00.557" Title="How is it possible that only the bottom half of the moon was showing?" Tags="|moon|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10863" PostTypeId="2" ParentId="10859" CreationDate="2017-07-19T17:27:05.140" Score="1" Body="&lt;p&gt;To add to Communnisty but too long for comment:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, open water with moderate temperatures, make them a bit cooler in summer or in tropics than otherwise would be likely, warmer in winter and in far north/south and where in the ocean currents a location is matters, but as a generality these statements are true.  So, in an area that is marginal for snow temperatures, say Seattle, they will receive less coastal snow because of the warmer temps.  Once you drop below the marginal temperature, say Mount Baker or Mount Rainier, still in the coastal moisture increase zone but higher altitude to push consistently below freezing in the winter, you have snow.   Lots and lots of it. &lt;/p&gt;&#xA;" OwnerUserId="6178" LastActivityDate="2017-07-19T17:27:05.140" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10865" PostTypeId="2" ParentId="10862" CreationDate="2017-07-19T20:51:44.037" Score="6" Body="&lt;p&gt;It depends on the season and even more on latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At any given time, the same side of the Moon faces the Sun.  Where you stand on Earth doesn't change which part of the Moon is lit, but if you think about the orientation of people on the earth, people in the Northern and Southern Hemisphere are &quot;upside down&quot; to each other and people on the equator are perpendicular.   The Moon doesn't change but the point of view of people on Earth relative to the Earth's surface makes a full 360 degrees of rotation based on latitude, so the same moon at the same time can appear as a left crescent, a right cresent, a boat and a yamaka depending on the person's latitude at the time of viewing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also &lt;a href=&quot;http://curious.astro.cornell.edu/physics/46-our-solar-system/the-moon/observing-the-moon/124-is-the-moon-seen-as-a-crescent-and-not-a-boat-all-over-the-world-is-the-same-phase-of-the-moon-visible-from-the-northern-and-southern-hemispheres-advanced&quot; rel=&quot;noreferrer&quot;&gt;explained here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And this should probably be astronomy.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2017-07-19T20:51:44.037" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10867" PostTypeId="2" ParentId="10823" CreationDate="2017-07-20T01:24:55.673" Score="5" Body="&lt;p&gt;The definition of a fossil is &quot;evidence of past life preserved by geologic processes&quot;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;By this definition a coal bed is itself a fossil since it is the preserved organic matter from an ancient swamp.  Oil and Natural Gas that are formed by the change of dead algae under the heat and pressure of being buried in the earth.  These would also be fossils.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Methane, discussed in another answer, can form inorganically in the solar system and there are people who claim to have found geologically ancient deposits of it remaining from the time of earth's formation.  Even if these claims are accepted (and they are controversial) it is only a very small amount of our natural gas supplies that are not the result of ancient organic processes.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2017-07-20T01:24:55.673" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10868" PostTypeId="2" ParentId="10860" CreationDate="2017-07-20T12:18:19.813" Score="0" Body="&lt;p&gt;Well, one way would be to look through &lt;a href=&quot;https://www.amazon.co.uk/Introduction-Rock-Forming-Minerals-W-Deer/dp/0903056275&quot; rel=&quot;nofollow noreferrer&quot;&gt;The rock forming minerals&lt;/a&gt; and see how many are represented.  I strongly suspect that not all would be, so from that perspective the answer would be No. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But from an inspection perspective..  For any given mineral structure, we can make changes by simply substituting various cations and anions as in &lt;a href=&quot;https://en.wikipedia.org/wiki/Pyroxene&quot; rel=&quot;nofollow noreferrer&quot;&gt;pyroxene&lt;/a&gt;; for example, we can substitute Mg(2+) for Fe(2+). Or SiO4(4-) for AlO4(5-) - requiring other changes. So, assuming you had suitable equipment, you could find a naturally occurring crystal that was close to the desired symmetry group and tweak it with substitutions until it matched that group.  Or more simply, adjust the pressure and temperature until the symmetry changed. There is a lot of phase space to explore.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So from that perspective, the answer would be probably yes, we just haven't synthesized them all yet.&lt;/p&gt;&#xA;" OwnerUserId="8217" LastActivityDate="2017-07-20T12:18:19.813" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10869" PostTypeId="2" ParentId="10860" CreationDate="2017-07-20T13:12:59.697" Score="5" Body="&lt;p&gt;Now all of the 230 space groups are realized by a natural occurring mineral.&#xA;I found this blog: &lt;a href=&quot;https://crystalsymmetry.wordpress.com/230-2/&quot; rel=&quot;nofollow noreferrer&quot;&gt;crystalsymmetry.wordpress.com&lt;/a&gt; where space groups are listed with at least one chemical compound is listed for each space group. Minerals are listed for all of the space groups.&lt;/p&gt;&#xA;&lt;p&gt;For example, Benitoite has fairly unusual crystal symmetry. I think it was first mineral found for P-6c2 space group.&lt;/p&gt;&#xA;&lt;h1&gt;188 P-6c2 Example – Benitoite, BaTi(Si3O9)&lt;/h1&gt;&#xA;&lt;p&gt;From &lt;a href=&quot;http://rruff.info/uploads/ZK74_139.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Crystal Structure of Benitoite.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;From a crystallographical point of view this compound (Benitoite)&#xA;is especially interesting, being the only known member of the ditrigonalbipyramidal&#xA;symmetry class.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-09-22T12:05:40.793" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10870" PostTypeId="1" CreationDate="2017-07-20T13:24:31.550" Score="4" ViewCount="285" Body="&lt;p&gt;I'm using &lt;a href=&quot;https://users.cs.jmu.edu/bernstdh/Web/CS159/pa1/Background_UltravioletIndex.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; source to calculate the UVI value for every hour in a day (From 7am to 7pm). And using &lt;a href=&quot;https://pysolar.readthedocs.io/en/latest/&quot; rel=&quot;nofollow noreferrer&quot;&gt;pysolar&lt;/a&gt; module to get the &lt;code&gt;Solar Zenith Angle&lt;/code&gt;. The equation is below:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;from pysolar.solar import *&#xA;from math import cos&#xA;import datetime&#xA;&#xA;dobj = datetime.datetime(2017,7,1,8,0)&#xA;sza = float(90)-get_altitude(42.57952, 1.65362, dobj)&#xA;ozone = 300&#xA;raw_uvi = 12.50*pow(cos(sza),2.42)*pow(float(ozone)/300,-1.23)&#xA;print (raw_uvi)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The output is:&#xA;    0.4850283419701262+1.8890606693266203j&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is when cos(sza) becomes negative it will give a complex number as output, how can I handle this ? Also, at 7 am the uvi results in &lt;code&gt;9.232276464148745&lt;/code&gt; which is wrong. Am I missing something ? Or my interpretation of the algorithm is wrong  ?&lt;/p&gt;&#xA;" OwnerUserId="5065" LastActivityDate="2017-07-21T15:32:00.237" Title="How to handle negative cosine of Solar Zenith Angle while calculating clear-sky UV Index?" Tags="|clouds|ozone|python|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10871" PostTypeId="2" ParentId="10870" CreationDate="2017-07-20T15:43:13.180" Score="2" Body="&lt;p&gt;&lt;strong&gt;This is only to address the title question&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You are right, in a way. I would recommend that you set an if statement up such that &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;code&gt;if cos(sza)&amp;gt;=0:&#xA;   raw_uvi = 12.50*pow(cos(sza),2.42)*pow(float(ozone)/300,-1.23)&#xA;else: &#xA;   raw_uvi=0.0&lt;/code&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This makes it so that when the sun is beneath the horizon, the sun is not 'taking back' the energy&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2017-07-21T15:32:00.237" LastActivityDate="2017-07-21T15:32:00.237" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10873" PostTypeId="1" AcceptedAnswerId="10874" CreationDate="2017-07-20T20:12:52.797" Score="2" ViewCount="372" Body="&lt;p&gt;Yilmaz (2016) briefly explains - along with a nice accompanied image/diagram - the main categories of seismic inversion. He claims there are four: travel-time, waveform, hybrid, and join inversion. Now, I have heard the phrase &quot;amplitude inversion,&quot; too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am now left wondering what exactly is or what constitutes amplitude inversion...? Also, is impedance inversion a type of waveform inversion? Finally, is amplitude inversion also a type of waveform inversion. Obviously, I'm putting a lot in here, so I would greatly appreciate if someone could resolve my confusion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Öz Yilmaz (2016). ”Image-based near-surface modeling for statics corrections.” &lt;em&gt;The Leading Edge&lt;/em&gt; &lt;strong&gt;35&lt;/strong&gt; (11), 961–967.&#xA;&lt;a href=&quot;https://doi.org/10.1190/tle35110961.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1190/tle35110961.1&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8447" LastEditorUserId="28050" LastEditDate="2018-04-05T00:30:31.577" LastActivityDate="2018-04-05T00:30:31.577" Title="Post-stack seismic impedance (and amplitude) inversion confusion" Tags="|seismic|inversion|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10874" PostTypeId="2" ParentId="10873" CreationDate="2017-07-20T21:11:40.700" Score="2" Body="&lt;p&gt;Here is the figure in question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HpRli.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HpRli.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Traveltime inversion&quot; is a very broad category that includes any inverse problem where the input data is a time-delay from a seismic source impulse to when it is received at a seismometer. This includes refraction tomography, reflection tomography, and most implementations of full-waveform inversion (i.e. using diving waves). The output (i.e. what you are solving for) here is a velocity model that best explains all time-delay data simultaneously given the known physics of wave propagation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Waveform inversion&quot; is the category that includes all post-migration reflection seismic inverse problems where the input is a single trace or an offset gather (constant X,Y for all input reflections). The output in these are the vertically-varying elastic properties (acoustic impedance, vp/vs, density, etc) that best explain the observed seismic trace/gather (i.e. waveform) given the physics of seismic reflection. This is commonly called &quot;amplitude inversion&quot; because amplitude is one of the main inputs here (although phase and frequency are involved as well).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Hybrid inversion&quot; is what Yilmaz is calling the recent methods that try to use both the seismic time-delays and ampltidues/waveforms to solve for the best elastic property model that simultaneously explain both types of observations. He cites some recent examples in that paper. The first one I saw on this was Misra and Sacchi (2008). The problem with this stuff is that things become highly nonlinear and therefore require global optimization techniques which are way slower. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Joint inversion&quot; is just combining different types of geophysical data. For example, let's say you are trying to map the 3D structure of a salt dome. You can use 3D seismic reflection data to map the top of a salt dome easily, but the base is usually really tough due to imaging problems below the salt. Gravity data only gives you the cumulative response of the entire 3D structure below so many salt dome shapes could give you the same gravity response. However, you can use the seismic data to map the top of the salt, then the gravity data to constrain the base, then use that model to re-migrate the seismic data and you should have a good top and base of salt. Similarly, you could pose the problem as a joint-inverse problem where you are looking for the best 3D structural model that simultaneously properly migrates the seismic data and also explains the gravity response.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this helps!&lt;/p&gt;&#xA;" OwnerUserId="4636" LastEditorUserId="4636" LastEditDate="2017-07-20T21:16:50.500" LastActivityDate="2017-07-20T21:16:50.500" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10875" PostTypeId="1" AcceptedAnswerId="10878" CreationDate="2017-07-21T03:47:48.337" Score="4" ViewCount="323" Body="&lt;p&gt;Let me state upfront, I'm not arguing the existence of climate change, just trying to clarify my own understanding of something that doesn't make sense to me yet. With apologies for the layman's question...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've seen similar numbers frequently, but let's use &lt;a href=&quot;https://xkcd.com/1379/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this xkcd&lt;/a&gt; &#xA;as a reference. It states that a 4.5 C change in the global climate is the difference between Boston under a half mile of ice, and the temperate zone it is today. Boston's current annual average temp is &lt;a href=&quot;http://www.usclimatedata.com/climate/boston/massachusetts/united-states/usma0046/2017/1&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.75&lt;/a&gt; (~15 average high, ~7 average low). Looking for an analog for a city that's about 4.5 C cooler than Boston gives a location like &lt;a href=&quot;https://www.currentresults.com/Weather/Canada/Cities/temperature-annual-average.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Moncton, New Brunswick.&lt;/a&gt; Colder, yes, but not buried under half a mile of ice. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My brain says that a place covered by ice is far colder than current temps minus 4.5 C, and that since the ice sheets covered so much of the earth, I can safely skirt the &quot;climate is global, you're looking at local temps&quot; hangup. So what gives? &lt;strong&gt;How can a climate like Boston's cool by &quot;only&quot; 4.5 C and support such enormous glaciers?&lt;/strong&gt; It would seem that the presence of such enormous ice sheets would imply that the average temperature must have been far colder than that...&lt;/p&gt;&#xA;" OwnerUserId="9630" LastActivityDate="2017-07-21T07:04:03.950" Title="Making sense of the math of climate change" Tags="|climate-change|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="10876" PostTypeId="1" AcceptedAnswerId="10880" CreationDate="2017-07-21T06:05:56.003" Score="14" ViewCount="5911" Body="&lt;p&gt;Sea level rise from melting glaciers will not be uniformly distributed across the globe.  However, it isn't clear to me what places will have the most and least extreme changes in sea level rise.  I had previously thought that, in general, tropical latitudes would have the least sea level rise, and the polar regions would have the most sea level rise.  However, when I view &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/5/5e/M2_tidal_constituent.jpg&quot; rel=&quot;noreferrer&quot;&gt;this map&lt;/a&gt; of tidal variation, and also consider the change in mass on the land (&lt;a href=&quot;https://earthscience.stackexchange.com/questions/9607/dataset-for-expected-sea-level-rise-in-case-of-massive-meltdowns-greenland-anta&quot;&gt;when the glacier melts&lt;/a&gt;), it appears that sea-level rise will be complex.  I've seen &lt;a href=&quot;http://www.soest.hawaii.edu/coasts/sealevel/MSL_Map_MERGED_Global_IB_RWT_NoGIA_Adjust.png&quot; rel=&quot;noreferrer&quot;&gt;this image&lt;/a&gt; of recent sea level change, but I don't think a change of several meters would continue to follow this trend.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How will sea level rise be distributed across the globe?&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2021-07-10T03:14:39.030" LastActivityDate="2021-07-12T03:41:03.810" Title="How will sea level rise be distributed across the globe?" Tags="|climate-change|oceanography|sea-level|glaciology|tides|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10877" PostTypeId="2" ParentId="10876" CreationDate="2017-07-21T06:36:23.213" Score="5" Body="&lt;p&gt;The sea level will rise uniformly due to thermal expansion of the seas, but you are right that glaciers make things more complex. Basically when a massive glacier melts its gravitational pull is redistributed in the ocean. For example if all of the antarctic ice would melt sea levels would rise everywhere, but with a largest rise in the north pole and smallest in the south.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is also currently rising of the earths crust in areas that were pushed down by the last ice age glaciers. Therefore where the current glaciers melt away earth will gradually be rising. When earth is rising at the ocean floor it forces the water to flow uniformly to everywhere else.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also changes in weather systems change the prevailing winds that affect where water will pack, but this effect is much smaller in the long run.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately all the predicting maps I found, like this interactive one &lt;a href=&quot;http://geology.com/sea-level-rise/&quot; rel=&quot;nofollow noreferrer&quot;&gt;geology.com&lt;/a&gt;, don't take into account these factors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some articles for more info: &lt;a href=&quot;http://ocean.si.edu/sea-level-rise&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ocean Portal&lt;/a&gt;, &lt;a href=&quot;http://e360.yale.edu/features/the_secret_of_sea_level_rise_it_will_vary_greatly_by_region&quot; rel=&quot;nofollow noreferrer&quot;&gt;Yale&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastEditorUserId="6465" LastEditDate="2017-07-21T09:34:23.820" LastActivityDate="2017-07-21T09:34:23.820" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="10878" PostTypeId="2" ParentId="10875" CreationDate="2017-07-21T07:04:03.950" Score="6" Body="&lt;p&gt;I was able to dig up this (although without being able to find full sources):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/scD2h.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/scD2h.gif&quot; alt=&quot;ice age temp map&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It shows a pattern where the temperatures are dramatically lower where ice sheets have built up relative to today. Interestingly, a lower overall temperature means weaker mixing across latitudes, so some areas are actually warmer.  Boston gets chilled by -20 according to the map.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also note the altitude effect. If the surface is raised by 1 kilometer, then due to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Lapse_rate&quot; rel=&quot;noreferrer&quot;&gt;lapse rate&lt;/a&gt;, the temperature at the new surface will drop by 6.5 degrees. This is a &lt;em&gt;very&lt;/em&gt; important factor in stabilizing large ice sheets.&lt;/p&gt;&#xA;" OwnerUserId="8217" LastActivityDate="2017-07-21T07:04:03.950" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10879" PostTypeId="2" ParentId="7106" CreationDate="2017-07-21T09:25:59.560" Score="1" Body="&lt;p&gt;Just to add, cause I don't see it in the answers above.   Continents are no heavier than oceans.   As far as the Earth is concerned, they weigh about the same and they drift according to the flow of the mantle underneath.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Qet0f.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Qet0f.png&quot; alt=&quot;https://qph.ec.quoracdn.net/main-qimg-0c45130b76a53362063b36df567c5d08&quot;&gt;&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Like marshmallows in cocoa, sometimes they will drift and touch (and by touch, I mean, crash into each other and form Himalaya sized mountain ranges) and sometimes they will float apart.   There's nothing strange about the continents all being together.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2017-07-21T09:25:59.560" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10880" PostTypeId="2" ParentId="10876" CreationDate="2017-07-21T12:41:55.797" Score="8" Body="&lt;p&gt;Sea level rise (SLR) is anything but spatially uniform. The satellite derived SLR rates that you present are a good example of the complexity of the spatial response. &#xA;A good way to explore the spatial characteristics from observations is to use the data from the Permanent Service for Mean Sea Level (&lt;a href=&quot;http://www.psmsl.org&quot; rel=&quot;noreferrer&quot;&gt;PSMSL&lt;/a&gt;). They have a good interactive &lt;a href=&quot;http://www.psmsl.org/products/trends/&quot; rel=&quot;noreferrer&quot;&gt;map&lt;/a&gt; to investigate global mean sea level trends since 1900. The time limits can be adjusted to see the changes depending on the data you use.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/xIz9r.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xIz9r.jpg&quot; alt=&quot;PSMSL&quot;&gt;&lt;/a&gt; Source PSMSL.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From their website:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The latest IPCC report, published in 2013, finds that &quot;It is very likely that the mean rate of global averaged sea level rise was 1.7 [1.5 to 1.9] mm/yr between 1901 and 2010, 2.0 [1.7 to 2.3] mm/yr between 1971 and 2010 and 3.2 [2.8 to 3.6] mm/yr between 1993 and 2010. Tide-gauge and satellite altimeter data are consistent regarding the higher rate of the latter period&quot; (&lt;a href=&quot;http://www.climatechange2013.org&quot; rel=&quot;noreferrer&quot;&gt;www.climatechange2013.org&lt;/a&gt;). &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That rate is the global AVERAGE but it varies a lot spatially. No location on Earth needs to have this average value (some will). In some places, sea level is rising by more than the global average while in others it is decreasing. There are many causes to for these local differences in sea level. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The regional differences are caused by changes in many variables. For instance, there wind patterns change in annual and decadal scales. As wind changes, wind-driven ocean currents are modified, which modify sea level slopes (e.g., Gulf Stream causes sea elevations gradients). Temperature changes in the oceans are also spatially variable resulting in steric sea level changes (local difference in density and volume change). Additionally, with ice sheets melt, there are changes in pressure over the crust modifying sea level. Other very local effects such as earthquakes, groundwater extraction, and subsidence of the land will cause apparent change of sea level at that location. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, the areas near the poles have a negative trend (sea level is dropping, not rising) because of the Glacial Isostatic Adjustment (&lt;a href=&quot;http://www.psmsl.org/train_and_info/geo_signals/gia/&quot; rel=&quot;noreferrer&quot;&gt;GIA&lt;/a&gt;) as the crust is still rebounding from the previous glaciation. In mid-latitudes, on the other hand the sea level rise rates are maximum. Of course, there are local effects because of many of the forcings mentioned above.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2017-07-21T15:09:25.410" LastActivityDate="2017-07-21T15:09:25.410" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="10882" PostTypeId="1" AcceptedAnswerId="11894" CreationDate="2017-07-21T14:22:43.777" Score="2" ViewCount="139" Body="&lt;p&gt;We are two high schoolers who would like to embark on a project to simulate the atmospheres of exoplanets.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More specifically, we would like to change the atmospheric composition of such planets. We have seen various climate models, such as CESM and PlaSim. Unfortunately, CESM appears to be quite complex, while the latter option doesn't have the resources we would need.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any other simulators that may consistently do the same thing, but need lower computer specifications? Otherwise, are there any resources to become familiar with CESM at a high school level?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, what would be the required specifications for running CESM on a fairly consistent basis? I have heard that you would need a cluster, but we currently do not have access to one. We may be able to rent one out, but we'd rather be familiar with CESM before we do.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: (for clarification) I know a bit of FORTRAN, and have access to help from a Physics instructor. Although I understand that it may be out of the reach of two high school students, is there any sort of &quot;crash course&quot;, one could recommend on more advanced astronomical physics?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, we are interested in a rocky exoplanet, and potentially have access to a cluster/help from a professor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you once again!&lt;/p&gt;&#xA;" OwnerUserId="9631" LastEditorUserId="9631" LastEditDate="2017-07-23T00:07:56.213" LastActivityDate="2017-07-23T03:43:22.570" Title="Different atmospheric models available for personal usage?" Tags="|meteorology|simulation|astronomy|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="10883" PostTypeId="2" ParentId="10882" CreationDate="2017-07-21T21:58:12.077" Score="1" Body="&lt;p&gt;Unfortunately, I don't think such a numerical model exists that would be suitable for high school students' understanding. The simplest climate model around is a zero-dimensional (energy balance) climate model, but a background on mathematics, and programming may be necessary. You can find one &lt;a href=&quot;http://www.cims.nyu.edu/~mostovyi/Course/EBM/zero_dim_ebm.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. &lt;a href=&quot;http://en.wikipedia.org/wiki/Idealized_greenhouse_model&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; has one listed. Michael Mann has the &lt;a href=&quot;http://www.meteo.psu.edu/holocene/public_html/supplements/EBMProjections/&quot; rel=&quot;nofollow noreferrer&quot;&gt;source code for such a model&lt;/a&gt;, but it is written in MATLAB (you may be able to run it in OCTAVE, since MATLAB is licensed). There are likely many more than just these, considering multiple layers, volcanic eruptions, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The code for the models listed are simplified models that do not consider things like clouds, aerosols, eddy diffusion, etc. This is where Global Climate Models (GCMs) differ. They must consider how fine details, some of which aren't considered by weather models, affect the climate. Therefore, they are usually complicated. Most GCMs I have seen are written in FORTRAN, which is an antiquated language, but computationally efficient. This makes even easy concepts obtuse.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While I have not dealt specifically with CESM, I can infer some things about it. By definition, CESM is an earth systems model, not an exoplanet model. You may be able to adapt some of the parameters to other planets, but it becomes too difficult for just one person to do (because of FORTRAN). There are models for other places, such as GCMs for Mars, but they are difficult to run and not necessarily accurate. Clusters are needed due to memory limitations, and how long they run for.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-07-21T21:58:12.077" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="10884" PostTypeId="1" AcceptedAnswerId="12493" CreationDate="2017-07-21T22:32:13.793" Score="3" ViewCount="334" Body="&lt;p&gt;I've been testing how amplitude scaling subsequently affects the results of gapped/non-gapped deconvolution and an impedance inversion algorithm called BLIMP (Ferguson and Margrave, 1996). Indeed, scaling the amplitude of the input seismic data (whether linearly or non-linearly) greatly affects the final result of both deconvolution and inversion. I am confused by this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's look at the convolution model in its full mathematical form: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ s(t) = [R(t) \ast W(t) + N(t)] \times A(t)$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $s(t)$ is the observed seismic trace, $R(t)$ is the reflectivity time series (or perhaps impulse response if you want a more realistic/complicated situation), $W(t)$ is the source wavelet, N(t) is the additive, random noise component, and finally $A(t)$ is the amplitude. Also, note that $\ast$ denotes convolution and $\times$ denotes multiplication. I understand the convolution model in this mathematical context, but I am failing to transfer that knowledge to grasp how amplitude could so greatly affect deconvolution or inversion calculations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If anyone has any papers, personal insight, or both to provide, please do so.&lt;/p&gt;&#xA;" OwnerUserId="8447" LastEditorUserId="28050" LastEditDate="2018-04-05T00:21:25.147" LastActivityDate="2018-04-05T00:21:25.147" Title="Amplitude scaling in seismic inversion" Tags="|seismic|inversion|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10885" PostTypeId="2" ParentId="9084" CreationDate="2017-07-21T22:33:02.910" Score="3" Body="&lt;p&gt;The Bermuda high is centered near the horse latitudes, where air from the tropical Hadley trade wind cell is sinking. This forced sinking of air can dynamically contribute to high pressure even if the air is warm --- warm air can be forced to sink against its own buoyancy in a Ferrel-type circulation. But the Bermuda high is helped thermally too, at least in summer, because the Atlantic Ocean at those latitudes, at least in summer, is cooler than North America and much cooler than the Sahara at the same latitudes. It is certainly easier for a Ferrel-type circulation to work against cooler surface temperatures than against warmer ones.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-07-21T22:33:02.910" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="10886" PostTypeId="1" CreationDate="2017-07-22T00:20:49.560" Score="1" ViewCount="2599" Body="&lt;p&gt;I would like to calculate (estimate) air temperature at given time, location and altitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All I have is air pressure for 20°C. The formula based on NTP (Normal Temperature and Pressure) to calculate pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;=101325*(1 - 2,25577*10^-5*h)^5,25588&lt;/p&gt;&#xA;&#xA;&lt;p&gt;h is height in meters` result is in Pascals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I expect that the formula for calculation of the temperature would depend on sun position or even solar radiation. I know that the formulas for calculation of the sun position or solar radiation are complicated but maybe there are source codes/programs which can do that? So I could use such program to calculate what I need? I have found SolTrack (C/C++) on SourceForge which calculates various data like rise time, transit time, azimuth, altitude, ecliptic longitude, latitude, right ascension, declination... However I cannot use these results to calculate temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Purpose of the calculation&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to use the calculation for game, to generate air temperatures for map. The game is not simulator it is just game. So I need to add some values to the map so when the aircraft flies it can accept some temperature changes. The values are important in vicinity of terrain, mountains and hills. I don't need include winds into the calculation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Calculation of Solar Radiation&lt;/strong&gt;&#xA;What I have found so far is calculation of solar radiation written in Visual Basic - it is xls table (Excel) &lt;a href=&quot;http://ecy.wa.gov/programs/eap/models/solrad.zip&quot; rel=&quot;nofollow noreferrer&quot;&gt;ecy.wa.gov/programs/eap/models/solrad.zip&lt;/a&gt;. Where I have added the pressure for 20°C. Of sure the problem here is unsolved because I suppose the temperature and pressure changes during time. So I need to improve the formula to calculate the pressure for given location, time and altitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Additional information:&lt;/strong&gt;&#xA;&lt;br&gt;Site data and time info:&#xA;&lt;br&gt;latitude in decimal degrees (positive in northern hemisphere)&#xA;&lt;br&gt;longitude in decimal degrees (negative for western hemisphere)&#xA;&lt;br&gt;ground surface elevation (m)&#xA;&lt;br&gt;time zone in hours relative to GMT/UTC (PST= -8, MST= -7, CST= -6, EST= -5)&#xA;&lt;br&gt;daylight savings time (no= 0, yes= 1)&#xA;&lt;br&gt;start date to calculate solar position and radiation&#xA;&lt;strong&gt;start time&lt;/strong&gt;&#xA;&lt;br&gt;time step (hours):&#xA;&lt;br&gt;number of days to calculate solar position and radiation&#xA;&lt;br&gt;Bird model parameters:&#xA;&lt;br&gt;barometric pressure (mb, sea level = 1013)&#xA;&lt;br&gt;ozone thickness of atmosphere (cm, typical 0.05 to 0.4 cm)&#xA;&lt;br&gt;water vapor thickness of atmosphere (cm, typical 0.01 to 6.5 cm)&#xA;&lt;br&gt;aerosol optical depth at 500 nm (typical 0.02 to 0.5)&#xA;&lt;br&gt;aerosol optical depth at 380 nm (typical 0.1 to 0.5)&#xA;&lt;br&gt;forward scattering of incoming radiation (typical 0.85)&#xA;&lt;br&gt;surface albedo (typical 0.2 for land, 0.25 for vegetation, 0.9 for snow)&#xA;&lt;br&gt;Bras model parameter:&#xA;&lt;br&gt;Bras atmospheric turbidity factor (2=clear, 5=smoggy, default = 2)&#xA;&lt;br&gt;Ryan-Stolzenbach model parameter&#xA;&lt;br&gt;Ryan-Stolzenbach atmospheric transmission factor (0.70-0.91, default 0.8)&#xA;&lt;br&gt;Cloud attenuation parameters:&#xA;&lt;br&gt;Coefficient for cloud correction (default 0.65)&#xA;&lt;br&gt;Exponent for cloud adjustment (default 2)&#xA;&lt;br&gt;Cloud cover fraction (0-1)&lt;/p&gt;&#xA;" OwnerUserId="9637" LastEditorUserId="9637" LastEditDate="2017-07-22T09:47:22.080" LastActivityDate="2017-07-23T05:50:44.003" Title="How to calculate air temperature for given time, location and altitude?" Tags="|weather-forecasting|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="11886" PostTypeId="1" AcceptedAnswerId="11892" CreationDate="2017-07-22T00:52:28.693" Score="2" ViewCount="565" Body="&lt;p&gt;Most volcanoes in the &lt;em&gt;Pacific Ring of Fire&lt;/em&gt; have an explosive nature. This is due to high concentrations of water in their magma. Obviously, this magma comes from several kilometres below the earth's crust. How is it possible for magma to contain water at such depths? &lt;/p&gt;&#xA;" OwnerUserId="10637" LastEditorUserId="725" LastEditDate="2017-07-22T02:21:43.313" LastActivityDate="2017-07-22T10:17:57.457" Title="Water and explosive volcanoes in the Pacific ring of fire" Tags="|volcanology|magmatism|earth-system|igneous|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11887" PostTypeId="2" ParentId="11886" CreationDate="2017-07-22T02:28:07.440" Score="0" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;How is it possible for magma to contain water at such depths?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This can happen precisely because the magma is at such depths. Think of CO&lt;sub&gt;2&lt;/sub&gt; in soda or coke. When the drink is closed and pressurised, the CO&lt;sub&gt;2&lt;/sub&gt; is dissolved in the liquid. This means it's part of one physical &lt;a href=&quot;https://en.wikipedia.org/wiki/Phase_(matter)&quot; rel=&quot;nofollow noreferrer&quot;&gt;phase&lt;/a&gt;. There is one &quot;thing&quot; that contains the liquid and the CO&lt;sub&gt;2&lt;/sub&gt; together: the CO&lt;sub&gt;2&lt;/sub&gt; is not a gas! Only when you open  the bottle, the CO&lt;sub&gt;2&lt;/sub&gt; can escape being dissolved in the liquid, and separates from the liquid as a distinct gas phase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same thing happens in magmas. While the magmas are pressurised at depths they have water dissolved in them. Note that this water is not separate liquid water or vapour flowing around the magma. It is inside the magma in one physical entity. Think of dissolving salt in water - you can't see salt grains but it's there. Anyway, once the magma rises it loses pressure. This causes the water to separate out from the magma into a distinct vapour phase that rises and expands rapidly, causing the explosive eruption.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-07-22T02:28:07.440" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11889" PostTypeId="2" ParentId="10860" CreationDate="2017-07-22T06:36:35.690" Score="1" Body="&lt;p&gt;Quoting a mineralogist friend of mine:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I &lt;em&gt;think&lt;/em&gt; there are mineral representatives of all 230 known by now - some of the groups are much rarer than others, but there is nothing specifically prohibiting...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This shouldn't be too hard to figure out. There are databases that contain this information, webmineral is one of them. Here an example mineral called &lt;a href=&quot;http://webmineral.com/data/Lewisite.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;lewisite&lt;/a&gt; where you can see: Space Group: F d3m . Unfortunately, that website does not aggregate space group data. Maybe it's possible to contact the people who run the website to see if it's possible to add this feature.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-07-22T06:36:35.690" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11890" PostTypeId="2" ParentId="10838" CreationDate="2017-07-22T06:55:50.203" Score="1" Body="&lt;p&gt;&lt;strong&gt;Vredefort&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No extraterrestrial iridium anomaly: &lt;a href=&quot;http://adsabs.harvard.edu/full/1989LPSC...19..733F&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://adsabs.harvard.edu/full/1989LPSC...19..733F&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not sure I fully agree with them, because there is quite a lot of Ir there and their threshold of 200 pg/g seems somewhat arbitrary to me. They claim the Ir was derived from local rocks, but that's a hell lot of iridium!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Sudbury&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is an an iridium anomaly. Read all about it &lt;a href=&quot;http://www.nature.com/nature/journal/v429/n6991/full/nature02577.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here (paywalled)&lt;/a&gt; and &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1111/j.1945-5100.2010.01057.x/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;here (open access)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;but the KT boundary is the only one commonly mentioned…why?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Because it's the first one found, a nice story of serendipity, because it's the last really big one, and the one that killed the dinosaurs. Everything you need to make a good story - even though it's not unique.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Iridium (and other PGE) anomalies and pretty much common feature of impacts. &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S167498711730049X&quot; rel=&quot;nofollow noreferrer&quot;&gt;This paper&lt;/a&gt; shows attempts to link mass extinction events with impacts. This is a controversial issue, because you can also link massive volcanic events with mass extinctions, not only impact. But that's not for now - they do show iridium anomalies for all impacts. &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0012821X04000627&quot; rel=&quot;nofollow noreferrer&quot;&gt;That's another paper&lt;/a&gt; showing iridium anomalies for impacts, much older this time.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-07-22T06:55:50.203" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="11891" PostTypeId="2" ParentId="10886" CreationDate="2017-07-22T08:22:01.093" Score="1" Body="&lt;p&gt;The answer that you seek does not exist. There is no easy formula that might be useful. Deriving a temperature based on solar radiation is also unrealistic since the system has very large latencies and complex interactions so that you'd end up writing a full-blown weather model. This appears to be beyond the scope of your intentions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question you need to ask is which effects are relevant to you and how accurate you want your model to be. Also, which quantities do you require? The answers affect your course of action. Since you mention flying aircraft, you may likely want vertical profiles of atmospheric temperature above a given location. Also, which of the following effects do you need to include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Day/Night variation&lt;/li&gt;&#xA;&lt;li&gt;Clouds, rain&lt;/li&gt;&#xA;&lt;li&gt;Temperature inversions&lt;/li&gt;&#xA;&lt;li&gt;Effect of different terrains (ocean vs land for example)&lt;/li&gt;&#xA;&lt;li&gt;Large variations in geographical location&lt;/li&gt;&#xA;&lt;li&gt;possibly other things&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;A good starting point are standard atmospheres (c.f. &lt;a href=&quot;https://en.wikipedia.org/wiki/International_Standard_Atmosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/International_Standard_Atmosphere&lt;/a&gt;). Another approach would be to find real-world locations that are sufficiently similar to the locations you are interested in and provide measurements. These might be adapted to your situation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A simple approach might be to tabulate a base temperature and height for different climatic zones and seasons and then apply the atmospheric lapse rate (-6.5K per km height) to these values. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;On a final note, I don't know what you need this information for. But be aware that for many thermodynamic purposes, the errors that you make are not going to be that large anyway since even an error of 20-30K is only an error of around 10% in absolute temperature. So be sure to evaluate your precision requirements.&lt;/p&gt;&#xA;" OwnerUserId="681" LastEditorUserId="681" LastEditDate="2017-07-22T10:44:07.247" LastActivityDate="2017-07-22T10:44:07.247" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="11892" PostTypeId="2" ParentId="11886" CreationDate="2017-07-22T10:17:57.457" Score="0" Body="&lt;p&gt;Brief answer (on tablet)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When an oceanic plate is formed, the crust is hydrated by the hydrothermal vents systems at the ocean ridge where it forms (hydrated means that the minerals are altered to include water in their structure). When this crust is subducted in the ocean trenches around the Pacific, it is taken down towards the mantle; as these hydrated minerals heat up again, they release water. This water then lowers the melting point of the mantle above the descending plate, which melts to produce a basaltic/andesitic melt with a high water content - the water is dissolved in the magma. When this melt reaches the surface again, the high concentration of water leads to explosive eruptions as it comes out of solution.&lt;/p&gt;&#xA;" OwnerUserId="8217" LastActivityDate="2017-07-22T10:17:57.457" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11894" PostTypeId="2" ParentId="10882" CreationDate="2017-07-23T01:27:01.453" Score="1" Body="&lt;p&gt;I think there's stuff out there that you can use. The key is searching for &quot;intermediate complexity models&quot;, or &quot;toy atmosphere models&quot; (where toy is science jargon for simple model that does things qualitatively right, but not useful for precise quantitative prediction). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of your question &quot;are there any other simulators that consistently do the same thing&quot;, I'm not sure what you mean.. do you mean a simulator that will produce the same solution/climate state for the same set of initial conditions? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the question &quot;what would be the required specifications for running CESM on a fairly constant basis?&quot;, that's going to depend on how complex of a simulation you set up. For example, if you are running a detailed simulation (high spatial and/or temporal resolution) and you want to have data for multiple variables at every grid cell through time, then you'll need supercomputing resources. If you were able to get access to one, you usually have to reserve time a few months in advance, run your simulation, and hope it worked out. With cluster computing, you would have to reduce the simulation size (compared to the supercomputer example), but you'd get more freedom to run multiple simulations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a small list of less computationally intensive and self-contained models&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) The first is called &lt;a href=&quot;http://math.bard.edu/student/pdfs/jonathan-fivelsdal.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;fast climate&lt;/a&gt; and is written in matlab &lt;a href=&quot;http://www.met.nps.edu/~psguest/polarmet/clichange/fastclimate_code.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;code&lt;/a&gt;. I know nothing about it, but it looks to be self-contained. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Also i just came across a GCM that claims to be user friendly called &lt;a href=&quot;http://edgcm.columbia.edu&quot; rel=&quot;nofollow noreferrer&quot;&gt;EDgcm&lt;/a&gt;. I know nothing about it, but it looks worth digging into. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) There's an intriguing app called &quot;&lt;a href=&quot;http://www.brown.edu/Research/Environmental_Physics/Environmental_Physics/Code.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;GCM&lt;/a&gt;&quot; I've honestly never messed around with it, but it could be worth a shot.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;4) Here's an &lt;a href=&quot;https://icp.giss.nasa.gov/education/geebitt/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;energy balance climate model&lt;/a&gt; that can be executed in excel.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you're determined to use a GCM, I think you could probably get CESM working using either the &lt;a href=&quot;http://www.cesm.ucar.edu/models/simpler-models/aquaplanet.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;aquaplanet&lt;/a&gt; or &lt;a href=&quot;http://www.cesm.ucar.edu/models/simpler-models/dry-dynamical-core.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;dry dynamical core&lt;/a&gt; setups. Depending on how simple you set it up, you could likely run it just on a standard PC. Another option you have is &lt;a href=&quot;http://mitgcm.org&quot; rel=&quot;nofollow noreferrer&quot;&gt;MITgcm&lt;/a&gt;, which can also be configured to run very bare-bones simulations that don't require much computational power. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have a university near you, I would consider seeing if there are any climate modeling groups, and reach out to see if there are any grad students willing to lend a little support. I know grad students who spend usually the first semester of their phd trying to get a simulation going.&lt;/p&gt;&#xA;" OwnerUserId="6221" LastEditorUserId="6221" LastEditDate="2017-07-23T03:43:22.570" LastActivityDate="2017-07-23T03:43:22.570" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11895" PostTypeId="2" ParentId="10820" CreationDate="2017-07-23T01:50:42.937" Score="1" Body="&lt;p&gt;Ozone absorbs nearly all incoming solar radiation at wavelengths less than .25 microns (and in so doing, protects us from skin cancer), but also absorbs in the infrared / terrestrial wavelengths. And this absorption band does not intersect the nearby absorption band for H2O (9 vs 10 to 20 microns for water vapor) or the primary wavelengths where CO2 absorbs. See &lt;a href=&quot;http://www.astronomy.ohio-state.edu/~pogge/Ast161/Unit5/atmos.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.astronomy.ohio-state.edu/~pogge/Ast161/Unit5/atmos.html&lt;/a&gt; for a discussion of the Greenhouse Effect and the atmospheric window.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This means that a depletion of the ozone would allow the earth to radiate to space around the 9 micron wavelength where the presence of water vapor and CO2 makes no difference. The present &quot;hole&quot; in the ozone over the Antarctic should be keeping the atmosphere cooler (especially the stratosphere) than otherwise by allowing radiation around 9 microns to escape to space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A thinning of the ozone in the upper atmosphere will allow more UV energy to reach the surface, but will also allow more IR to escape back to space. Clear as mud, right?&lt;/p&gt;&#xA;" OwnerUserId="6313" LastActivityDate="2017-07-23T01:50:42.937" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="11896" PostTypeId="1" AcceptedAnswerId="11909" CreationDate="2017-07-23T03:15:57.053" Score="3" ViewCount="293" Body="&lt;p&gt;From reading articles and the such it is clear that other planets such as Jupiter have storms that lasts months over months. However on Earth, storms last much shorter. In fact, the longest storm was &lt;a href=&quot;https://en.wikipedia.org/wiki/Hurricane_John_(1994)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Typhoon/Hurricane John&lt;/a&gt; which lasted a mere 31 days. Such long storms are commonly found on other planets. So why don't we have long storms?&lt;/p&gt;&#xA;" OwnerUserId="7242" LastEditorUserId="5887" LastEditDate="2023-06-04T01:12:33.907" LastActivityDate="2023-06-04T01:12:33.907" Title="Why are storms relatively short on Earth?" Tags="|planetary-science|storms|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="11897" PostTypeId="2" ParentId="6911" CreationDate="2017-07-23T03:52:51.853" Score="-1" Body="&lt;p&gt;A necessary (but not sufficient) condition for hurricanes to form on Earth if there was no water (dry hurricanes) is that the lapse rate would have to exceed the dry adiabatic by a large enough margin over a sufficiently large region of the troposphere. By contrast, with water vapor, this necessary (but not sufficient) condition is mitigated to a lapse rate merely exceeding the moist adiabatic by a large enough margin over a sufficiently large region of the troposphere. Dry hurricanes have been simulated on computers. While the laws of physics don't forbid dry hurricanes in principle, in practice it would be at least very difficult and maybe impossible to attain the the required steep lapse rate over a sufficiently large region of the troposphere, even with no solar energy expended in evaporation on a dry Earth.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-07-23T03:52:51.853" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="11898" PostTypeId="1" CreationDate="2017-07-23T04:06:27.337" Score="2" ViewCount="91" Body="&lt;p&gt;I am taking a course on coursera where the instructor talks of a &lt;strong&gt;soil subsidence concrete post&lt;/strong&gt; that was put there in &lt;strong&gt;Everglades southern Florida in 1920s&lt;/strong&gt;. He goes on to describe the level of earth that has decreased over the years due to &lt;strong&gt;soil subsidence&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now there have been rains on the earth for years and in past couple of centuries, the area for agriculture has increased significantly which in my opinion leads to increased soil subsidence due to irrigation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Doesn't this continuous rainfall and irrigation lead to higher subsidence and hence decrease in the diameter of the earth?&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="8520" LastActivityDate="2017-07-23T19:57:00.070" Title="Does the diameter of the earth decrease because of soil subsiding due to irrigation and rainfall over the years?" Tags="|geology|measurements|soil|agriculture|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="11900" PostTypeId="2" ParentId="10886" CreationDate="2017-07-23T05:50:44.003" Score="0" Body="&lt;p&gt;Agreeing with Christoph that the model you seek does not exist.  When I was in grad school I programmed a model that could calculate the surface temperature based on solar radiation plus a large number of factors including the current air temperature, slope and direction of the surface, amount of shading by vegetation, previous nightly low temperature plus some essentially unknowable quantities such as the thermal conductivity of the soil. About a dozen inputs if I remember correctly. The model showed a good match to observations but was not a climate or weather model which is what you are asking for in your game.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2017-07-23T05:50:44.003" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="11901" PostTypeId="1" AcceptedAnswerId="11904" CreationDate="2017-07-23T15:05:46.830" Score="2" ViewCount="93" Body="&lt;p&gt;Just wondering about this question has been popped into my head many times and as what I have seen in some volcanic activities that when a volcano erupts there's a lightning, &amp;amp; i don't know if there's really a storm but I do think volcanoes do attracted to lightning or it produces it's own? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do volcanoes attracts to lightning? &lt;/p&gt;&#xA;" OwnerUserId="10637" LastActivityDate="2017-07-23T23:09:26.423" Title="Volcanoes and Lightning" Tags="|volcanology|lightning|" AnswerCount="2" CommentCount="1" ClosedDate="2017-07-25T08:17:16.790" ContentLicense="CC BY-SA 3.0" />
  <row Id="11902" PostTypeId="2" ParentId="11901" CreationDate="2017-07-23T19:27:05.487" Score="-1" Body="&lt;p&gt;Erupting volcanoes release ash. When ash particles collide, it can build a static charge. When that charge is released, there is lightning.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-07-23T19:27:05.487" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="11903" PostTypeId="2" ParentId="11898" CreationDate="2017-07-23T19:46:06.673" Score="4" Body="&lt;p&gt;Disclaimer: this is probably TLWR, but you can absolutely apply some physical reasoning to arrive at the answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Changes in surface height of the earth are governed by the conservation of mass, i.e. that if mass ($M$) is removed in one location (everglades soil erosion), then an equal amount of mass must be gained at another location (perhaps accretion on the seafloor).The total change in the earths mass is zero $$\Delta M = M_1-M_2=0$$&#xA;$$-M_1=M_2$$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mass may be broken up into the volume ($V=\Delta x \Delta y \Delta z$) multiplied by density ($\rho$), so $M=\rho V$. In terms of the conservation of mass equation from above, then:&#xA;$$-\rho_{1} \Delta x_1 \Delta y_1 \Delta z_1 = \rho_{2} \Delta x_2 \Delta y_2 \Delta z_{2}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The place where erosion occurs is described by the left side (with subscript 1). The place where accretion occurs is described by the right side (with subscript 2). This equation says the total mass lost by area 1, must equal the total mass gained by area 2. Now consider the following two situations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;1) The transported sediment &lt;em&gt;does not undergo&lt;/em&gt; any change in density&lt;/strong&gt;. If the density does not change, you have $\rho_1=\rho_2$. Let's also say the eroding area ($\Delta x_1 \Delta y_1$) equals the accreting area ($\Delta x_2 \Delta y_2$) for simplicity. Then all equal terms in the conservation of mass cancel out and you're left with&#xA;$$-\Delta z_{1} = \Delta z_{2}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;2) The transported sediment &lt;em&gt;does undergo&lt;/em&gt; a change in density&lt;/strong&gt;. There's a host of reasons why density &lt;em&gt;can&lt;/em&gt; change. If the density changes then we can't let the density terms cancel in the conservation of mass. Lets still say the eroding area and accreting area are equal. The conservation of mass becomes &#xA;$$-\rho_1 \Delta z_1 = \rho_2 \Delta z_2$$&#xA;or conversely &#xA;$$-\Delta z_1=\frac{\rho_2}{\rho_1}\Delta z_2$$&#xA;This says that the amount of change in height at location 1 is not equal to the amount of change at location 2 (sure they're proportional, but not definitely not exactly equal).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Putting it all together to answer the question&lt;/strong&gt;, the average earth radius (r)  is the average of all heights (z) with respect to the center of the earth $$r=\frac{z_1+z_2+...+z_n}{n}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Try this all out with arbitrary numbers to convince yourself&lt;/strong&gt;. Add the changes $\Delta z_1$ to $z_1$, and $\Delta z_2$ to $z_2$&#xA;$$r_{before}=\frac{z_1 + z_2 + z_3}{3}$$ &#xA;$$r_{after}=\frac{(z_1+\Delta z_1)+(z_2+\Delta z_2)+z_3}{3}$$&#xA;Rearrange $r_{after}$ to be&#xA;$$r_{after}=\frac{z_1+z_2+z_3 + (\Delta z_1+\Delta z_2)}{3}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Case 1&lt;/strong&gt; If density doesn't change (i.e. $-\Delta z_1=\Delta z_2$), then $$r_{after}=\frac{z_1+z_2+z_3 + (\Delta z_1-\Delta z_1)}{3}$$&#xA;The changes cancel out and $r_{before}=r_{after}$. The earths radius does not at all change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Case 2&lt;/strong&gt; If the density changes, $r_{after}$ becomes&#xA;$$r_{after}=\frac{z_1+z_2+z_3 + (\Delta z_1-\frac{\rho_2}{\rho_1}\Delta z_1)}{3}$$&#xA;and you can see that $r_{after}$ does not equal $r_{before}$.&lt;/p&gt;&#xA;" OwnerUserId="6221" LastEditorUserId="6221" LastEditDate="2017-07-23T19:57:00.070" LastActivityDate="2017-07-23T19:57:00.070" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11904" PostTypeId="2" ParentId="11901" CreationDate="2017-07-23T23:09:26.423" Score="1" Body="&lt;p&gt;Volcanic lightning was documented by one of the earliest American volcanologists, &lt;a href=&quot;https://en.wikipedia.org/wiki/Frank_A._Perret&quot; rel=&quot;nofollow noreferrer&quot;&gt;Frank A. Perret&lt;/a&gt; in the 1940s. However, there was not much, if any, study of the phenomena until recently. According to &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2015GL067445/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt;, the electric charge develops close to the ground where the plume gas thrust region at a few hundred meters above the crater rim, where the overpressure of the turbulent volcanic jets determines the electrification of particles generating a complex charge structure in the growing plume.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2016GL068076/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;The abstract of another journal article&lt;/a&gt; indicates that additional lightning can be generated in the stratosphere, &quot;Observations and volcanic plume modeling further suggest that electrical activity was enhanced both by ice formation in the ash clouds &gt;10 km above sea level and development of a low-level charge layer from ground-hugging currents.&quot;&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-07-23T23:09:26.423" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11905" PostTypeId="1" CreationDate="2017-07-24T02:18:21.350" Score="3" ViewCount="307" Body="&lt;p&gt;In textbooks it is mentioned that &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Magnetic anomaly = Observed Geomagnetic field - Theoretical Geomagnetic field&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;observed value is measured using instruments like proton precession magnetometer or flux gate magnetometer etc , whereas Theoretical values are computed by IGRF formula which takes coordinates , elevation of the point as input . (&lt;a href=&quot;https://www.ngdc.noaa.gov/geomag-web/#igrfwmm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ngdc.noaa.gov/geomag-web/#igrfwmm&lt;/a&gt; )&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My doubt is regarding error in anomaly calculation . In the observed part the error is in the range 0.1 - 1 nT depending on the instrument . IGRF error for total field is around 152 nT .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xF4CE.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xF4CE.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(from : &lt;a href=&quot;https://www.ngdc.noaa.gov/geomag/WMM/limit.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ngdc.noaa.gov/geomag/WMM/limit.shtml&lt;/a&gt; )&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore our total error in magnetic anomaly calculation is around 152-153 nT . In such case if our anomaly  ( observed - theoretical )  is small (say around 30 nT ) , what would be the validity of such observation as the value we are trying to estimate is smaller than the margin of error .&lt;/p&gt;&#xA;" OwnerUserId="594" LastActivityDate="2018-10-22T10:17:05.840" Title="Calculating error in measuring geomagnetic Anomalies using IGRF" Tags="|geophysics|geomagnetism|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="11906" PostTypeId="1" AcceptedAnswerId="11912" CreationDate="2017-07-24T11:17:41.237" Score="1" ViewCount="77" Body="&lt;p&gt;I first saw the term &amp;quot;Imilac meteorite&amp;quot; in this &lt;a href=&quot;http://www.bbc.com/news/science-environment-40459602&quot; rel=&quot;nofollow noreferrer&quot;&gt;BBC News article&lt;/a&gt;. It shows a photograph of a meteorite on display along with the caption:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Imilac meteorite was found in the Atacama Desert in Chile in 1822.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I then looked it up in Wikipedia's article &lt;a href=&quot;https://en.wikipedia.org/wiki/Imilac&quot; rel=&quot;nofollow noreferrer&quot;&gt;Imilac&lt;/a&gt; and saw:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Imilac is a pallasite meteorite found in the Atacama Desert of Northern Chile in 1822.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Both of these sound like there is one meteorite, and it's is called the Imilac meteorite.&lt;/p&gt;&#xA;&lt;p&gt;But then the article goes on to say:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Classification:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Imilac is classified as a stony–iron pallasite. Imilac specimens are highly prized by meteorite collectors due to its high concentration of beautiful olivine grains.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Strewn field:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Numerous masses were found in a valley to the SW of Imilac. The total weight of the Imilac fall is estimated to be around 1,000 kilograms (2,200 lb). The primary strewn field is long about 8 kilometres (5.0 mi).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;There seems to be multiple, distinct specimens, and yet I don't see &amp;quot;Imilac meteorites&amp;quot; (plural) written here or anywhere. For example, in this British Natural History Museum article &lt;a href=&quot;http://www.nhm.ac.uk/discover/imilac-meteorite-gem-as-old-solar-system.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Imilac meteorite: a gem as old as the solar system&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Pallasite meteorites like the Imilac formed in the asteroid belt, located between Mars and Jupiter. They are made up of minerals and metal, remnant materials from the first few million years of the solar system.&lt;/p&gt;&#xA;&lt;p&gt;They formed inside asteroids at a time when planets were only just coming together.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So are all of these Imilac specimens believed to be fragments of one single object that exploded before reaching the surface? If so, why not call them Imilac meteorites (plural) instead of talking about &amp;quot;Imilac meteorite&amp;quot; as a name for a material that is uncountable?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RtgRr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RtgRr.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-07-25T00:13:28.887" Title="Should Imilac (meteorite) be singular or plural?" Tags="|terminology|meteorite|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11907" PostTypeId="1" CreationDate="2017-07-24T11:41:19.627" Score="3" ViewCount="326" Body="&lt;p&gt;I know that the Axial Tilt of Earth is about 23.4° - 23.5°. And I would like to know how much this change effects Solar Radiation for particular geo-location.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the Axial Tile change rate? How often or how fast does it change? How much precision do we need when we calculate Solar Radiation for Weather forecast?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What could be difference between 1920, 1939. 1945, 1950 or 2017 Axial Tilt and it's effect on Solar Radiation at particular geo-location?&lt;/p&gt;&#xA;" OwnerUserId="9637" LastEditorUserId="9637" LastEditDate="2017-07-24T12:36:02.587" LastActivityDate="2017-07-25T07:59:34.930" Title="How much is Solar Radiation effected by Axial Tilt or Obliquity?" Tags="|meteorology|weather-forecasting|astronomy|axial-obliquity|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="11909" PostTypeId="2" ParentId="11896" CreationDate="2017-07-24T18:54:07.963" Score="2" Body="&lt;p&gt;The main driving force for storms to form at all are the equator-pole temperature gradients. The main reason  for them to stop is friction between the lower atmosphere and earth's surface. This friction counteracts geostrophic balance (the balance between the pressure gradient and the coriolis force). Longer storms can only sustain themself through latent heat release, which can act as a secondary driver (and is the reason that Hurricanes/Typhoons can last rather long). However, at the latest at landfall this mechanism stops and the storm will decay. On gas-planets, however, there is no surface, therefore friction is much less (only the friction between different layers of the atmosphere, which is much less). Once a storm develops, with a low pressure centre, there is no (or hardly) any friction which counteracts geostrophic balance. This allows the storms to exist much longer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to other non-gas planets:&#xA;Mars and Mercury have a very thin atmosphere, therefore, as far as I know, there is no weather as on earth anyway. As for Venus, which has an atmosphere, I do not know.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that also on Earth, some weather circulations last much longer than the couple of days that storms last, for example the polar vortex, which lasts the whole winter (and is far away from the earths surface). Especially if you compare the gas-planets, you might also see them as &quot;storms&quot; in the wider sense.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;references:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(lack) of atmospheres on Mars and Mercury: &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Mars&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Atmosphere_of_Mars&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Mercury&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Atmosphere_of_Mercury&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;no surface on Jupiter: &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Jupiter&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Atmosphere_of_Jupiter&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;disturbance of geostrophic flow due to friction: &lt;a href=&quot;https://en.wikipedia.org/wiki/Ageostrophy&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Ageostrophy&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;formation of storms in general: &quot;An Introduction to Dynamic Meteorology - James R. Holton&quot;, Chapter 9, and 11&lt;/p&gt;&#xA;" OwnerUserId="10647" LastEditorUserId="10647" LastEditDate="2017-07-27T07:41:59.370" LastActivityDate="2017-07-27T07:41:59.370" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="11910" PostTypeId="2" ParentId="11907" CreationDate="2017-07-24T19:10:08.027" Score="1" Body="&lt;p&gt;Check out this matlab program that is presented in a paper by &lt;a href=&quot;https://www.geosci-model-dev.net/7/1051/2014/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kostadinov and Gilb, 2014&lt;/a&gt;. The paper is worth reading, and they have their full matlab code in the &quot;supplement&quot; link (top right corner under downloads). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The code launches a GUI. From it you can control the values of obliquity, eccentricity, precession, total solar irradiance, day of year, calendar start year and end year,  and latitude. Section 2.1 in the paper explains the coordinate system. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't think anyone could answer off the top of their heads the question &quot;what is the difference between 1920, 1939, etc... of solar radiation at a particular geo-location&quot;. But with this program, you can mess around with the data and find out. So let us know what you discover! (ps, if you don't have Matlab, you can probably use this in octave which is free). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a screenshot of the gui&#xA;&lt;a href=&quot;https://i.stack.imgur.com/u1otz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/u1otz.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And here's what some of the output looks like &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0EWpk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0EWpk.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's some alternatives to matlab: &lt;br&gt;&#xA;1) &lt;a href=&quot;https://data.giss.nasa.gov/ar5/solar.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;nasa&lt;/a&gt; has online calculator that spits out raw text tables of insolation.&lt;br&gt;&#xA;2) If you are savvy with fortran then you may like this &lt;a href=&quot;http://vo.imcce.fr/insola/earth/online/earth/earth.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;fortran code&lt;/a&gt;.&lt;br&gt;&#xA;3) The fortran code above also has an &lt;a href=&quot;http://vo.imcce.fr/insola/earth/online/earth/online/&quot; rel=&quot;nofollow noreferrer&quot;&gt;online interface&lt;/a&gt;&lt;br&gt;&#xA;4) If you like python, then you may like this &lt;a href=&quot;https://github.com/brian-rose/climlab&quot; rel=&quot;nofollow noreferrer&quot;&gt;python code, climlab&lt;/a&gt;, where there are detailed &lt;a href=&quot;http://www.atmos.albany.edu/facstaff/brose/classes/ATM623_Spring2015/Notes/Lectures/Lecture12%20--%20Orbital%20variations.html#section5&quot; rel=&quot;nofollow noreferrer&quot;&gt;instructions here&lt;/a&gt; on how to use the code and visualize the information.&lt;br&gt;&#xA;5) If you like R, then try &lt;a href=&quot;https://cran.r-project.org/web/packages/palinsol/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;palinsol&lt;/a&gt; which has a little &lt;a href=&quot;https://cran.r-project.org/web/packages/palinsol/palinsol.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;documentation here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6221" LastEditorUserId="6221" LastEditDate="2017-07-24T22:45:53.373" LastActivityDate="2017-07-24T22:45:53.373" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="11911" PostTypeId="1" CreationDate="2017-07-24T20:50:32.673" Score="2" ViewCount="284" Body="&lt;p&gt;For a personal project, i wanted to develop a global atmospheric database, to compile data like wind speed and direction, temperature, etc. from different sources. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is this : &#xA;Does such a database exist? either in a free or paying format.&lt;/p&gt;&#xA;" OwnerUserId="10648" LastActivityDate="2017-08-03T00:45:33.730" Title="Is there an atmospheric data database somewhere on the web?" Tags="|atmosphere|atmosphere-modelling|database|" AnswerCount="2" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="11912" PostTypeId="2" ParentId="11906" CreationDate="2017-07-25T00:13:28.887" Score="1" Body="&lt;p&gt;Without knowing if there's an official statement on that, I can give my common sense opinion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are fragments that came from one single meteorite, or one single &#xA;&quot;formation&quot;. Let's say that we have a basalt flow, let's call it the Michael Basalt. It's fragmented, right? So there are a bunch of pieces of it. If I collect the pieces, those are still several pieces of the &quot;Michael Basalt&quot;. If I would refer to basalts instead, that would imply that there were several flows, not only one. But there is one. So I have several samples of the singular Michael Basalt. Therefore, there are several samples of the singular Imilac meteorite.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-07-25T00:13:28.887" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="11913" PostTypeId="1" CreationDate="2017-07-25T02:50:06.960" Score="12" ViewCount="15753" Body="&lt;p&gt;I know the Earth is nearest to Sun during the summers of the southern hemisphere. Does the orbit affect the climate actually? For example, would there be any difference if the Earth had a perfectly circular orbit?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If so, what is the effect of it? For example, does it cause hotter summers in southern hemisphere, or would it cause the southern hemisphere to receive more solar UV radiation?&lt;/p&gt;&#xA;" OwnerUserId="3384" LastEditorUserId="2470" LastEditDate="2017-07-25T08:24:17.143" LastActivityDate="2020-03-10T18:52:23.657" Title="Does the elliptical orbit of the Earth have effect on Earth's climate?" Tags="|climate|orbit|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11914" PostTypeId="2" ParentId="11913" CreationDate="2017-07-25T06:28:30.977" Score="0" Body="&lt;p&gt;The distance of earth to sun is proportional to the intensity of sunlight we receive. The distances between perihelion and aphelion are quite small, so the differences in sunlight intensities are too - &lt;a href=&quot;https://en.wikipedia.org/wiki/Perihelion_and_aphelion&quot; rel=&quot;nofollow noreferrer&quot;&gt;wiki&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the alternative circular orbit would be the average radius of the current ellipse then northern hemisphere summers would have slightly more intense sunlight, hotter, and and vice versa for the southern hemisphere, cooler (less UV).&lt;/p&gt;&#xA;" OwnerUserId="6465" LastActivityDate="2017-07-25T06:28:30.977" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="11915" PostTypeId="2" ParentId="11907" CreationDate="2017-07-25T07:41:57.277" Score="1" Body="&lt;p&gt;&lt;em&gt;&quot;Obliquity of the ecliptic for 20,000 years, calculated by Laskar (1986) reflects change from 24.2° to 22.5°.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/1/14/Obliquity_of_the_ecliptic_laskar.PNG/620px-Obliquity_of_the_ecliptic_laskar.PNG&quot; rel=&quot;nofollow noreferrer&quot;&gt;Diagram&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Until 1983 the obliquity for any date was calculated from work of &lt;a href=&quot;https://en.wikipedia.org/wiki/Newcomb%27s_Tables_of_the_Sun&quot; rel=&quot;nofollow noreferrer&quot;&gt;Newcomb&lt;/a&gt;, who analyzed positions of the planets until about 1895:&#xA;ε = 23° 27′ 08″.26 − 46″.845 T − 0″.0059 T2 + 0″.00181 T3&#xA;where ε is the obliquity and T is tropical centuries from B1900.0 to the date in question.&lt;/em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Ecliptic#cite_note-13&quot; rel=&quot;nofollow noreferrer&quot;&gt;[13]&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;From 1984, the Jet Propulsion Laboratory's DE series of computer-generated ephemerides took over as the fundamental ephemeris of the Astronomical Almanac. Obliquity based on DE200, which analyzed observations from 1911 to 1979, was calculated:&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;code&gt;ε = 23° 26′ 21″.45 − 46″.815 T − 0″.0006 T2 + 0″.00181 T3&lt;/code&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;where hereafter T is Julian centuries from J2000.0.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Ecliptic#cite_note-14&quot; rel=&quot;nofollow noreferrer&quot;&gt;[14]&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;JPL's fundamental ephemerides have been continually updated. The Astronomical Almanac for 2010 specifies:&lt;/em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Ecliptic#cite_note-15&quot; rel=&quot;nofollow noreferrer&quot;&gt;[15]&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;code&gt;ε = 23° 26′ 21″.406 − 46″.836769 T − 0″.0001831 T2 + 0″.00200340 T3 − 0″.576×10−6 T4 − 4″.34×10−8 T5&lt;/code&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;These expressions for the obliquity are intended for high precision over a relatively short time span, perhaps ± several centuries.&lt;/em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Ecliptic#cite_note-16&quot; rel=&quot;nofollow noreferrer&quot;&gt;[16]&lt;/a&gt; &lt;em&gt;J. Laskar computed an expression to order T10 good to 0″.04/1000 years over 10,000 years.&lt;/em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Ecliptic#cite_note-laskar-12&quot; rel=&quot;nofollow noreferrer&quot;&gt;[12]&lt;/a&gt;&#xA;&lt;em&gt;All of these expressions are for the mean obliquity, that is, without the nutation of the equator included. The true or instantaneous obliquity includes the nutation.&lt;/em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Ecliptic#cite_note-17&quot; rel=&quot;nofollow noreferrer&quot;&gt;[17]&lt;/a&gt;&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: Wikipedia - &lt;a href=&quot;https://en.wikipedia.org/wiki/Ecliptic#Obliquity_of_the_ecliptic&quot; rel=&quot;nofollow noreferrer&quot;&gt;Obliquity of the ecliptic&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From historical Total Solar Irradiance records there is evident, that the great changes of TSI doesn't correspond to the Axial Tilt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I could not found how much local solar radiation can be affected by Obliquity. But I have found that local solar radiation is called &lt;a href=&quot;https://simple.wikipedia.org/wiki/Insolation&quot; rel=&quot;nofollow noreferrer&quot;&gt;insolation&lt;/a&gt;. &lt;em&gt;&quot;Factors affect insolation (without the effect of the atmosphere):&#xA;    Angle of the sun&#xA;    Distance between the sun and the earth&#xA;    Duration of daylight&#xA;The longer the duration of daylight, the more the insolation received per day.&quot;&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="9637" LastEditorUserId="9637" LastEditDate="2017-07-25T07:59:34.930" LastActivityDate="2017-07-25T07:59:34.930" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="11916" PostTypeId="2" ParentId="11913" CreationDate="2017-07-25T08:37:16.297" Score="6" Body="&lt;p&gt;&lt;strong&gt;Yes&lt;/strong&gt;, but this is not mainly due to the small intensity variation of sunlight with distance.  Rather, the elliptical orbit affects the length of the seasons, which — along with other orbital effects — triggers the ice ages.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Currently, in the northern hemisphere, summers are longer than winters, because of Kepler's orbit laws and the fact that perihelion is in the northern hemisphere winter.  However, there is precession in the date of perihelion, and periodically over tens of thousands of years, it shifts into the northern hemisphere winter.  This causes enough of a difference to trigger the ice ages: see &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;noreferrer&quot;&gt;Milkankovitch cycles&lt;/a&gt; on Wikipedia.&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2017-07-25T08:37:16.297" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="11917" PostTypeId="2" ParentId="11913" CreationDate="2017-07-25T08:47:41.417" Score="14" Body="&lt;p&gt;Short answer.   When the Earth is closest to the sun in January that softens the seasonal variation in the Northern Hemisphere and it increases the seasonal variation in the Southern Hemisphere, so for now, in the Northern Hemisphere, the Summers are colder than they would be with a circular orbit and the winters are hotter.   The opposite is true in the Southern Hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Overall the eccentricity variation doesn't change how much solar energy hits the Earth by much, so it's not the total solar energy.   It's when combined with precession, and the effect on the seasons, that the global effect can be significant. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we had a perfectly circular obit then the only Milankovich cycle that would matter would be &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles#Axial_tilt_.28obliquity.29&quot; rel=&quot;noreferrer&quot;&gt;axial tilt&lt;/a&gt;.  Ice ages would either be on a 41,000 year cycle - very neat and tidy, or they wouldn't happen at all cause the orbital variation wouldn't be enough to get ice ages started.  Other factors, like solar minimums could play a role and over longer periods of time, continental drift and variations in plant life, so, maybe not that exactly that, but I think it's likely.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Too long answer:   Hotter summers and colder winters (or the opposite) is a form of climate change that accompanies the orbital cycles.  All the orbital cycles change climate at least by seasonally.  But if I'm reading your question right, you're asking about global temperature, not just seasonal variation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Eccentricity has an effect because the two hemispheres are quite different and because it amplifies the effect of &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles#Apsidal_precession&quot; rel=&quot;noreferrer&quot;&gt;precession&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oceans tend to be a temperature buffer.  They circulate and they warm up slowly and they cool down slowly so they don't get too hot in summer or too cold in winter.  Land can vary in temperature significantly more.   This buffering can be seen in this average temperature chart of the two hemispheres.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4S5bC.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4S5bC.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Northern Hemisphere varies about 13 degrees C and the Southern about 5.5 C.   Those numbers might seem low, but remember that near the equator, seasonal variation is small and there's more land near 0 latitude than up near 90 or -90.   How accurate this chart is, isn't really relevant.   It doesn't need to be perfect.  What's relevant is that seasonal variation is much smaller in the Southern Hemisphere because so much of it is ocean, even with the Sun being closest in January which should make the Southern Hemisphere season variation more extreme.  The ocean is the key factor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With that in mind we can ignore the smaller variation in the Southern Hemisphere and just look at the Northern Hemisphere variation for any orbataly driven climate effects.   Before we get into eccentricity, it's important to understand &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles#Axial_precession&quot; rel=&quot;noreferrer&quot;&gt;Axial Precession&lt;/a&gt;.   The Earth, as you noted, is closest to the Sun in early January, &lt;a href=&quot;https://www.timeanddate.com/astronomy/perihelion-aphelion-solstice.html&quot; rel=&quot;noreferrer&quot;&gt;January 4th this year&lt;/a&gt;.  that 3.4% closer That means Earth gets nearly 7% more sunlight in the first week of January than it gets in the first week of June.   That 7% is too small to move the seasons, but it's enough to affect them a bit.   Earth overall gets more solar energy January (Northern Hemisphere Winter) and less solar energy in June.   The Northern Hemisphere's more exteme seasonal variaiton comes into play when the Earth is closest to the Sun in May-June-July-August - that should happen in about 8,000 years, give or take.  The cycle averages about every 23,000 years, so roughly 11,500 years between highs and lows for each hemisphere.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most relevant factor is the Northern Hemisphere Summer.   This is what is thought to drive ice ages back and forth.   Snow can last on land a long time in higher Northern latitudes and when the summers are less hot, the snow can last well into May, June, even all year around.   The warmer winters are less of a factor cause you still get snow in warm winters, sometimes, it snows more heavily when the winter is warmer.    It's the cooler Northern Hemisphere Summers that allow snow build-up and make ice ages possible.  Eccentricity (combined with precession) plays a key role on the periodic, colder Northern Hemisphere summer.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Don't worry, we're not entering an ice age in a few thousand years.   We're actually in a cool Northern Hemisphere summer period now, but, It's not quite that automatic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles#Orbital_shape_.28eccentricity.29&quot; rel=&quot;noreferrer&quot;&gt;The eccentricity&lt;/a&gt; in effect, determines how significant the axial precession is.   When the orbit is nearly circular, the difference in energy perihelion to aphelion is virtually zero.   Orbital eccentricity is currently dropping, moving towards circular, so we're not in a period of expected significant changes.  (The increased CO2 would prevent an ice age now anyway, but that's another story).  Earth's orbital cycles are in more of a holding pattern than moving towards an ice age. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When eccentricity peaks, the variation in solar energy hitting the Earth, perihelion to aphelion is significant.   It's loosely speaking, about 4 times the eccentricity.  The current eccentricity is 0.017, the current variation, Early January to Early June is about 4 times that or 0.068 or 6.8%.   At peak eccentricity of about .0679 would work out to roughly 27% variation in solar energy hitting the Earth, Perihelion to Aphelion.  (Perhaps nearly 30% with the working out the square).   This 30% variation in solar energy, depending on the perihelion and aphelion fall on the calendar, is sufficient to make ice ages come and go.   ((For very high eccentricity this 4 times rule doesn't work, but it applies pretty close to eccentricity pretty close to 0.))&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In laymans terms, think of the eccentricity as turning up or down the effect of axial precession and those two combined, when properly lined up with the hemispheres, have a significant effect.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The 3 cycles together, make a kind of ugly chart of ups and downs.  The orbital effect is rather uneven but Ice ages are often periodic because of feedback mechanisms on Earth.  Once formed, Glaciers are hard to melt and once melted, it takes peak conditions to get them forming again, so many of the smaller ups and downs in the chart don't drive ice ages, only the extremes.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wikipedia has a nice graph on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles#Present_and_future_conditions&quot; rel=&quot;noreferrer&quot;&gt;Northern Hemisphere solar energy at summer solstice&lt;/a&gt;.   When the chart is high, that tends to be a period of glacial melt.  When it's low, that's a period of ice age formation.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because the eccentricity is currently kind of low and shrinking, we're probably not due for an ice-age for about 50,000 years, at least according to current orbital models, per Wikipedia (same link as just above).&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2017-07-25T08:47:41.417" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11918" PostTypeId="2" ParentId="11911" CreationDate="2017-07-25T16:21:30.373" Score="2" Body="&lt;p&gt;Wind speed, direction, temperature (highs and lows only or time of day?) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;And do you want this for all over the Earth or just regional, like the continental US?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this answer is correct, there are &lt;a href=&quot;http://www.answers.com/Q/How_many_weather_stations_are_there_in_the_world&quot; rel=&quot;nofollow noreferrer&quot;&gt;roughly 30,000 weather stations&lt;/a&gt; across the globe, 365 days a year that's about 11 million rows of data per year.   That's a large enough database where you'd need special software to handle it.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;And if you want hourly wind and weather (1 wind speed and direction per day is pretty limited), now you're over 250 million rows of data per year, unless you want to limit your database to highs and lows - which might be the way to go.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And if you want this going back 100 years, well, that's a monster amount of data.   There's also the problem that weather stations don't always stay in the same place.  In the 1990s they opened up a whole lot of new weather stations, a percentage of which have since been closed.  That makes for some fun reading, especially on the &lt;a href=&quot;http://www.foxnews.com/science/2013/08/13/weather-station-closures-flaws-in-temperature-record.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fox-News side&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This might be the best source, at least, the best I found doing a quick search.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ncdc.noaa.gov/cdo-web/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncdc.noaa.gov/cdo-web/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and daily:   &lt;a href=&quot;https://www.ncdc.noaa.gov/cdo-web/datatools/records&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncdc.noaa.gov/cdo-web/datatools/records&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They have a search function and a variety of datasets.   I haven't looked at them in detail.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This might also be of interest:   &lt;a href=&quot;https://en.wikipedia.org/wiki/Citizen_Weather_Observer_Program&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Citizen_Weather_Observer_Program&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also just noticed, most of this info is in the source data question &lt;a href=&quot;https://opendata.stackexchange.com/questions/10154/sources-of-weather-data/10155&quot;&gt;posted in comments&lt;/a&gt;.   (oops).&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2017-07-25T16:26:54.990" LastActivityDate="2017-07-25T16:26:54.990" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11919" PostTypeId="1" CreationDate="2017-07-25T17:40:22.763" Score="2" ViewCount="108" Body="&lt;p&gt;I am working on a project which involves taking over a business based in Italy. It is a small village situated near Rieti (Sabina Hills) called Casperia and I am wondering if it is on a fault line? Is there a risk of having more quakes in the centre of Italy? It's a business in the tourism industry, so it is very important for me to find out about the risks before I go ahead... Any suggestions welcome.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many thanks for your time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Adeline&lt;/p&gt;&#xA;" OwnerUserId="10652" LastActivityDate="2017-07-26T20:07:47.570" Title="Is the centre of Italy still at risk of earthquakes?" Tags="|seismology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="11920" PostTypeId="1" CreationDate="2017-07-25T18:13:34.683" Score="4" ViewCount="1068" Body="&lt;p&gt;The more I looked at this stone and touched it, the more this thing looked like it was wrapped in some kind of reptile skin. It may just be a random rock. More photos if needed. Does this look like something you may have seen before? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's mainly green/yellow in color except for the pattern on the rock. The skin like pattern is a very dark color, almost black. It's a very hard rock, not breakable. It seems to weigh what it should. Not too heavy or light. We were looking for fossils in a sand bar that was in the shallows of the Bogue Chitto River in Mt. Herman Louisiana. This river is fed by the Mississippi River. We found it a couple weeks after some severe weather. Rivers had gotten pretty high &amp;amp; were at flood stage. Once they receeded, we went on our adventure. We found several other fossils of shells, and small centipede looking fossils. We only picked this one up because it reminded us of an alligator toe. &lt;a href=&quot;https://i.stack.imgur.com/r7rgQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/r7rgQ.jpg&quot; alt=&quot;rock&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/D7F6x.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/foXiE.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CyO11.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PVMpV.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7uC8a.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="10653" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T21:13:00.487" LastActivityDate="2023-08-07T20:36:28.060" Title="Aligator or Dinosaur Fossil skin type rock" Tags="|fossils|paleontology|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="11922" PostTypeId="2" ParentId="10859" CreationDate="2017-07-25T23:36:43.743" Score="1" Body="&lt;p&gt;The warmer the air, the greater the water vapor pressure. So the heaviest snowfalls occur where and when it is as warm as possible without the snow melting --- just barely below freezing. If average temperatures are above freezing, temperatures being too high limits snow, and snow is more likely and heavier inland, away from the water whose high heat capacity moderates temperatures. If average temperatures are far below freezing, low water vapor pressure limits snow, and snow is more likely and heavier at the coast.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-07-25T23:36:43.743" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11923" PostTypeId="1" CreationDate="2017-07-26T02:04:12.983" Score="4" ViewCount="125" Body="&lt;p&gt;To a person living on a beach in the Caribbean or crossing the Atlantic on a sailing ship, it's not obvious whether a commotion in the sky is a hurricane or some other storm system. When did people realize that hurricanes are a unique type of storm?&lt;/p&gt;&#xA;" OwnerUserId="10655" LastActivityDate="2017-09-01T14:10:08.573" Title="When did people first realize that hurricanes are a particular type of storm system?" Tags="|meteorology|tropical-cyclone|history-of-science|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="11924" PostTypeId="1" AcceptedAnswerId="11929" CreationDate="2017-07-26T04:26:04.057" Score="1" ViewCount="316" Body="&lt;p&gt;I've tried looking it up on google but I can't find anything. I'm talking about when a small amount of water forms to look like a root hair structure, thin and branching out.&lt;/p&gt;&#xA;" OwnerUserId="10657" LastEditorUserId="2536" LastEditDate="2017-07-26T06:04:17.000" LastActivityDate="2017-07-26T19:43:51.623" Title="What is it called when water forms to look like a root structure?" Tags="|water|terminology|" AnswerCount="2" CommentCount="2" FavoriteCount="0" ClosedDate="2017-07-27T07:54:35.650" ContentLicense="CC BY-SA 3.0" />
  <row Id="11925" PostTypeId="2" ParentId="11924" CreationDate="2017-07-26T06:31:46.607" Score="-1" Body="&lt;p&gt;Given that you are talking about something &lt;strong&gt;small&lt;/strong&gt; and &lt;strong&gt;root-hair like&lt;/strong&gt; there are &lt;em&gt;no such examples&lt;/em&gt; occurring with water in the liquid phase. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's more likely you saw ice. In science jargon, what you're referring to are known as fractal structures. Below the pictures, I explain why water in the liquid phase can not produce the specific type of fractal structures you're asking about.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the photos below are not even close to what you were thinking of, and you're sure it wasn't ice, then you probably saw something that wasn't water (for example a clear mold). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's literally an infinite variety of these fractal ice patterns. Try googling the terms &lt;strong&gt;fractal, self-organized, self-similar, self-affine, patterned, or dendritic, complex network&lt;/strong&gt; followed by any of the words &lt;strong&gt;frost, ice, ice-crystal, snow, snowflake&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/0/0a/Frost_patterns_2.jpg&quot; alt=&quot;icey&quot;&gt;&#xA;&lt;img src=&quot;https://s-media-cache-ak0.pinimg.com/736x/5e/06/60/5e06603220a56a499e6cce1072ca0468--tree-photography-amazing-photography.jpg&quot; alt=&quot;icey&quot;&gt;&#xA;In response to comments, it's worth clarifying why small amounts of water cannot form &lt;em&gt;static fractal structures&lt;/em&gt;. Water has strong surface tension resulting from the polarity of individual $H_2O$ molecules. Surface tension is the reason water beads up to form &lt;em&gt;smooth&lt;/em&gt; edges, which is precisely the opposite condition of fractal structures. There are examples (like the structure left behind as water drips down a window) of limited branching with water, but the branching is physically limited by surface tension that forces smaller nearby water to coalesce with the larger structures. For fractal branching to be significant, you must have more than just a primary and secondary branching. That is to say, no scientist would consider something to be a fractal if it occurs over less than an order of magnitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rivers are a different story. Stream networks are fractal by several different measures. However, in line with the details of the question it's important to note &#xA;the poster asked about &lt;em&gt;water&lt;/em&gt; forming a root like structure. The fractality of river networks is a pattern embedded within the earths surface, yes by the action of water, but &lt;em&gt;water alone&lt;/em&gt; is not responsible for the network structure. To oversimplify, it's a sediment transport phenomenon, the flow is multi-phase (water + sediment), and therefore this is not just a water-only phenomenon.&lt;/p&gt;&#xA;" OwnerUserId="6221" LastEditorUserId="6221" LastEditDate="2017-07-26T19:43:51.623" LastActivityDate="2017-07-26T19:43:51.623" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="11926" PostTypeId="2" ParentId="4967" CreationDate="2017-07-26T10:48:17.690" Score="3" Body="&lt;p&gt;The answer is dependent on the geographical location. Over sea, there is hardly any diurnal cycle of lightning (this means that there is no time of the day when lightning is more/less often observed).&#xA;In continental regions (e.g. Siberia), however, there is a strong diurnal cycle of lightning: it is most common in the late afternoon, and least common in the early morning.&#xA;The third type of regions are regions mainly affected by mesoscale systems (as is the Great Lake region in the US): here, there is also a strong diurnal cycle, but the peak (most lightning) is shifted towards the late evening or early morning. Thus, to answer your question: in these regions, there is indeed more lightning at night.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reference:&#xA;Blakeslee, Richard J., et al. &quot;Seasonal variations in the lightning diurnal cycle and implications for the global electric circuit.&quot; Atmospheric research 135 (2014): 228-243.&lt;/p&gt;&#xA;" OwnerUserId="10647" LastActivityDate="2017-07-26T10:48:17.690" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11927" PostTypeId="1" AcceptedAnswerId="11928" CreationDate="2017-07-26T13:34:10.340" Score="1" ViewCount="187" Body="&lt;p&gt;I have a house's coordinates that I know is in LA, Ventura, or Orange county, California and it says the latitude and longitude are&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;latitude    longitude&#xA;34144442    -118654084&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;These seem really big. How can I find the address this corresponds to?&lt;/p&gt;&#xA;" OwnerUserId="5132" LastActivityDate="2017-07-26T13:52:24.167" Title="How to Interpret this set of Latitude and Longitude?" Tags="|measurements|mapping|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11928" PostTypeId="2" ParentId="11927" CreationDate="2017-07-26T13:52:24.167" Score="6" Body="&lt;p&gt;It looks like your coordinates are written in decimal degrees but with the decimal points omitted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;34.144442 -118.654084 corresponds to 34°08'40.0&quot;N 118°39'14.7&quot;W.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.co.uk/maps/place/34%C2%B008&amp;#39;40.0%22N+118%C2%B039&amp;#39;14.7%22W/@34.1785346,-119.0523377,10z/data=!4m5!3m4!1s0x0:0x0!8m2!3d34.144442!4d-118.654084&quot; rel=&quot;noreferrer&quot;&gt;Google maps&lt;/a&gt; shows this to be a location just outside LA.&lt;/p&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2017-07-26T13:52:24.167" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="11929" PostTypeId="2" ParentId="11924" CreationDate="2017-07-26T14:42:24.813" Score="2" Body="&lt;p&gt;The term you are looking for is &lt;strong&gt;Dendritic&lt;/strong&gt;, it literally means &quot;having a branched form resembling a tree&quot; and is used to describe the shape of rivers but can also apply to anything with that pattern. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/A6reT.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/A6reT.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2017-07-26T14:42:24.813" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="11930" PostTypeId="1" CreationDate="2017-07-26T18:22:46.577" Score="3" ViewCount="3472" Body="&lt;p&gt;I finally broke down and read the Wikipedia article on &lt;a href=&quot;https://en.wikipedia.org/wiki/Spontaneous_combustion&quot; rel=&quot;nofollow noreferrer&quot;&gt;spontaneous combustion&lt;/a&gt; and I was surprised to see how serious of a problem this can be. Wet hay, oily rags, there really are exothermic reactions in these combinations that speed up as the temperature increases.&lt;/p&gt;&#xA;&lt;p&gt;Then I saw the following:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Coal&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Self-heating in coal has been extensively studied. The tendency to self-heat decreases with increasing rank of the coal. Lignite coals are more active than bituminous coals, which are more active than anthracite coals. Freshly mined coal consumes oxygen more rapidly than weathered coal, and freshly mined coal self-heats to a greater extent than weathered coal. The presence of water vapor may also be important, as the rate of heat generation accompanying the absorption of water in dry coal from saturated air can be an order of magnitude or more than the same amount of dry air.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I understand that coal is a complex material, it's more than a lump of carbon. But what are the types of chemical reactions within coal that will cause a pile of it to self-ignite? Is moisture always required? Is there moisture in freshly mined coal naturally, or is it absorbed hygroscopically from the atmosphere or is a liquid source necessary (getting wet)?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-08-07T18:12:00.723" Title="Coal self-heating and spontaneous combustion, how does this happen?" Tags="|fossil-fuel|coal|" AnswerCount="4" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="11931" PostTypeId="2" ParentId="11919" CreationDate="2017-07-26T20:01:40.580" Score="4" Body="&lt;p&gt;The Italian Civil Defense's &lt;a href=&quot;http://www.eurometeo.com/english/read/doc_zone-sismiche&quot; rel=&quot;nofollow noreferrer&quot;&gt;map of earthquake risk zones&lt;/a&gt; shows Rieti in at &lt;em&gt;best&lt;/em&gt; Zone 2, &quot;Medium-high seismicity, quite strong earthquakes possible&quot;, and near or in Zone 1, &quot;High or catastrophic seismicity, strong earthquakes possible&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The map of &lt;a href=&quot;https://earthquaketrack.com/it-07-rieti/recent&quot; rel=&quot;nofollow noreferrer&quot;&gt;recent earthquakes in Rieti&lt;/a&gt; shows regular earthquake activity. Last year &lt;a href=&quot;https://earthquake-report.com/2016/08/24/very-strong-earthquake-central-italy-on-august-24-2016-2/&quot; rel=&quot;nofollow noreferrer&quot;&gt;an earthquake killed hundreds in Rieti&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There was a famous &lt;a href=&quot;http://www.sciencemag.org/news/2015/11/italy-s-supreme-court-clears-l-aquila-earthquake-scientists-good&quot; rel=&quot;nofollow noreferrer&quot;&gt;long legal case&lt;/a&gt; in Italy over earthquake predictions and warnings. &lt;/p&gt;&#xA;" OwnerUserId="2639" LastEditorUserId="2639" LastEditDate="2017-07-26T20:07:47.570" LastActivityDate="2017-07-26T20:07:47.570" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11932" PostTypeId="2" ParentId="4967" CreationDate="2017-07-26T21:34:46.393" Score="2" Body="&lt;p&gt;To help answer that, I'll start with a look at the broader country (and by extension, world), which is primarily my answer from a &lt;a href=&quot;https://physics.stackexchange.com/questions/223692/why-does-lightning-most-often-occur-at-night/323599&quot;&gt;similar question on Physics SE&lt;/a&gt;, slightly adapted:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's good to start with some foundation on what time of day lightning is most often seen.  Here is a plot from &lt;a href=&quot;http://Global%20electric%20circuit%20implications%20of%20combined%20aircraft%20storm%20electric%20current%20measurements%20and%20satellite-based%20diurnal%20lightning%20statistics&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global electric circuit implications of combined aircraft storm electric current measurements and satellite-based diurnal lightning statistics (Mach, Blakeslee, Bateman: 2011)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/i5bTf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/i5bTf.png&quot; alt=&quot;diurnal lightning&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And to add a better idea of how much regional variability is involved, this plot of peak lightning time from &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0493(2001)129%3C1179%3ACTGLIT%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cloud-to-Ground Lightning in the United States: NLDN Results in the First Decade, 1989–98 (Orville and Huffins: 2001)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0iVnx.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0iVnx.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The summary is that the majority of places see peaks during the afternoon, but there is variation, including perhaps a few parts of New York.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Generally, the mechanism responsible for the majority of storms heavily determines when peak times occur:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Devoid of other overwhelming factors, the afternoon will generally be favored in most areas.  This is because that is when peak atmospheric heating occurs.  To form a thunderstorm, air must rise until it can attain a level where it has cooled to being saturated.  Without external forcing mechanisms, the air rising must start warm and moist enough to reach this point.  This instability peaks during the daytime.  Nighttime air is indeed typically closer to being saturated (has a higher relative humidity)... but that is caused by the ground cooling; this cooling causes an &lt;a href=&quot;https://en.wikipedia.org/wiki/Inversion_(meteorology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;inversion&lt;/a&gt; of warmer air in the profile aloft, which further blocks rising motion.  Plus at night there are no longer the &lt;a href=&quot;https://en.wikipedia.org/wiki/Thermal&quot; rel=&quot;nofollow noreferrer&quot;&gt;thermals&lt;/a&gt; created by the ground heating that are often the source of the lift itself.&lt;br&gt;&#xA;Many regions indeed have these predominantly airmass thunderstorms, where most storms are found when warm-season airmasses reach their convective temperature during the afternoon (seen in places such as the interior southeast US).  For much more details into this lift process and all of these terms, &lt;a href=&quot;https://www.eoas.ubc.ca/courses/atsc201/A201Resources/SoundingTutorial1/SoundingTutorial1Readings.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this reference&lt;/a&gt; may prove helpful.&lt;/li&gt;&#xA;&lt;li&gt;Areas nearer warm coastlines are often heavily biased by the &lt;a href=&quot;http://oceanservice.noaa.gov/education/yos/resource/JetStream/ocean/seabreezes.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;sea breeze circulation&lt;/a&gt;.  Areas 50-100 miles inland would peak during the early or mid afternoon (see Florida).  Spots further inland may actually see a lesser (usually secondary) peak later into the evening because the (less common) deeper penetrations take longer (seen in places like central Georgia).  And locales right along the coast may see noctural peaks due to nearshore landbreeze storms (see right on the Gulf and Atlantic coasts).&lt;/li&gt;&#xA;&lt;li&gt;Regions dominated by synoptic storm systems will be biased by their relationship to the common development areas.  Areas should peak during the day if near where storms in these environments typically develop (often along mountain &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Lee_cyclogenesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;lees&lt;/a&gt;).  As those storm progress (eastward in the NH mid-latitudes), they often grow upscale into &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Mesoscale_convective_system&quot; rel=&quot;nofollow noreferrer&quot;&gt;squall lines&lt;/a&gt; or &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Mesoscale_convective_complex&quot; rel=&quot;nofollow noreferrer&quot;&gt;MCCs&lt;/a&gt;, such that in those areas further east, at least secondary peaks may be seen later into the evening or even night as the storms often move that way during this time period (can often see this in many parts of the Mississippi Valley).&lt;/li&gt;&#xA;&lt;li&gt;Some areas are heavily influenced by overnight &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Low-level_jet&quot; rel=&quot;nofollow noreferrer&quot;&gt;low-level jet&lt;/a&gt; storm development, and thereby peak during the night (such as the Great Plains).&lt;/li&gt;&#xA;&lt;li&gt;As &lt;a href=&quot;https://earthscience.stackexchange.com/a/11926/6298&quot;&gt;Sip noted&lt;/a&gt;, far out over sea, at least in warm areas (doubt there's much lightning over cold oceans!), the atmospheric profile is often more moistly saturated, leading to weak instability that can be more reasonably tapped any time, and thus a more random spread of convection times.  I don't have much history working on convective storms in remote ocean locations (do that many people!)... but I tend to imagine there's just not much lightning due to the weaker lift.  But regardless, it ties into one related interesting topic at least: the &lt;a href=&quot;http://www.atmos.albany.edu/student/sstevens/diurnal.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;diurnal radially increasing peak of lightning found in tropical cyclones over the ocean&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;One last factor that may impact our own experience is the reality that lightning is visually less distinct to us during the daytime.  Lightning can regularly be seen for hundreds of miles at night (often given the misnomer &lt;a href=&quot;https://weather.com/science/weather-explainers/news/heat-lightning-explainer&quot; rel=&quot;nofollow noreferrer&quot;&gt;heat lightning&lt;/a&gt;), whereas during the day, unless the sky is particularly dark or the actual channel is directly observed, often we'll only notice the thunder.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;But indeed, while lightning varies greatly geographically, overall it peaks during late afternoon due to the nature of convection, and aided by many of the local mechanisms that drive it.&lt;/strong&gt;&#xA;&lt;hr&gt;&#xA;Now, as to western New York, the &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0493(2001)129%3C1179%3ACTGLIT%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;NLDN reference&lt;/a&gt; also included flash density:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ER3ZB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ER3ZB.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Showing you're pretty limited in your lightning up that way.  But the time map does show some locations in western New York are more night-focused than many places in the US.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looks like it's heavily caused by the lake.  Over the lake the cool lake air should squash instability of incoming storms on warm afternoons.  Lake breezes might extend that lull somewhat further inland, though it would also feasibly kick off storms as they advance, too.  But I really doubt lake breezes up that way often get deeply developed enough to move inland and have a lot of influence during the summer.  I don't see any radar evidence over the past few days of any. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thinking some of the late-night lightning further inland, especially along the Tug Hill, might actually stem from the major lake effect snow events.  I'd think that such events might often be strongest at night because air-lake temperature difference is vital to LES, and temperatures are lowest at night of course (winds often slacken at night, potentially mitigating this, but I believe most LES, especially on the eastern shores, come in situations with strong synoptic flow, where nighttime wind decrease shouldn't be much of an issue).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not sure if you get enough thundersnow to really sway the needle towards night-time lightning.  Maybe as you cool at night, storms fire over the lake at night, equivalent to landbreezes.  Seems it may be a combination of factors that cause your fairly local peculiarity, but hopefully these ideas/factors offer at least a bit of insight!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2017-07-26T21:34:46.393" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="11933" PostTypeId="1" CreationDate="2017-07-26T22:06:15.233" Score="7" ViewCount="1227" Body="&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Does all commercially available helium come from natural gas wells?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Is it theoretically possible to have a pure helium well?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Helium is produced by the radioactive decay of primordial uranium and thorium.  It should not be strongly associated with non-primordial 'fossil' hydrocarbons.&lt;/p&gt;&#xA;" OwnerUserId="8212" LastEditorUserId="6129" LastEditDate="2020-05-07T11:27:25.300" LastActivityDate="2020-05-07T11:27:25.300" Title="Why is helium only found in wells mixed with natural gas?" Tags="|economic-geology|gas|fossil-fuel|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="11934" PostTypeId="1" CreationDate="2017-07-26T22:14:59.280" Score="3" ViewCount="116" Body="&lt;p&gt;There are different seismic sources for both land and marine acquisition surveys. Measuring the spectral characteristics (phase, frequency, amplitude, etc.) is a critical part of evaluating the usefulness of the source and is quite difficult to measure accurately (especially on land). We always seek to generate an impulse (&lt;em&gt;or&lt;/em&gt; a Dirac spike).    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;All this said, my question is this: &lt;em&gt;how&lt;/em&gt; and &lt;em&gt;why&lt;/em&gt; do different frequencies retain various &lt;strong&gt;phase&lt;/strong&gt; delays and &lt;strong&gt;amplitudes&lt;/strong&gt;? Is this a phenomenon that does not occur the instantaneous moment the source is used...? I used Seismic Unix to generate the figure below - note that a phase diagram is not included here, but you already know that there some degree of phase delay/difference associated with each frequency (&lt;strong&gt;note&lt;/strong&gt;: the horizontal axis is frequency and vertical is amplitude):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jxqJt.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jxqJt.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If my question seems vague, think of it this way. Let's say I (and my source) are in an infinite, elastic, and homogeneous medium. I set off my source (note that it is NOT a perfect impulse), and the result may look like what is pictured below. What causes frequencies to retain different amplitudes? What causes the phase delay associated with each frequency? I know I've included a lot here, regardless, any insight/comments are greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="8447" LastEditorUserId="28050" LastEditDate="2018-04-05T00:24:59.410" LastActivityDate="2018-04-05T00:24:59.410" Title="The phase of a seismic source" Tags="|seismic|" AnswerCount="0" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11935" PostTypeId="2" ParentId="11933" CreationDate="2017-07-26T23:28:32.210" Score="3" Body="&lt;p&gt;The helium in natural gas wells is created from uranium and thorium (as you correctly state) contained in the underlying granite basement rock or radioactive black shales that allows the natural gas to be trapped and contained. It's not that the helium is created from the fossil hydrocarbons, but that it comes from the rocks that trap those hydrocarbons (&lt;a href=&quot;https://en.wikipedia.org/wiki/Helium_production_in_the_United_States&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2017-07-26T23:28:32.210" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11936" PostTypeId="2" ParentId="11933" CreationDate="2017-07-27T06:49:15.533" Score="13" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Helium is produced by the radioactive decay of primordial uranium and thorium. It should not be strongly associated with non-primordial 'fossil' hydrocarbons.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The first statement is correct. The second is not. There are several reasons that helium should be strongly associated with non-primordial hydrocarbons. Both are fluids found predominately in the crust due to the highly lithophilic nature of uranium and thorium in the case of helium and the fossil origin in the case of hydrocarbons. Being a gas, helium is somewhat soluble in hydrocarbons. Like most gases, helium solubility in hydrocarbons increases with pressure. Unlike many gases, helium solubility in hydrocarbons increases with temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Trapped hydrocarbons thusly act as a trap for helium. In places where hydrocarbons aren't present, helium &lt;em&gt;might&lt;/em&gt; be trapped by some capping rock, or it might escape through the tiniest of pores. As the smallest gas (even molecular hydrogen is larger), helium is wont to find a way to escape to the surface -- unless temporarily trapped by a trapped liquid.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-07-27T06:49:15.533" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11937" PostTypeId="2" ParentId="11933" CreationDate="2017-07-27T09:17:03.990" Score="7" Body="&lt;p&gt;David Hammen's answer explains why He is extracted from natural gas. But, it is not found only there. Helium exists just about everywhere on earth. You find it in volcanoes, in subseafloor hydrothermal vents and even just slowly leaking away from the ground in U and Th rich zones. As with all extraction of natural resources, it comes down to economics. How much is there, can we extract it, and how much does it cost to extract it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Extracting the He from natural gas sources is easy: it's relatively concentrated, and we're drilling the thing anyway to get the gas out. Might as well get any by-products that are there, one of them being He. This is just like extracting indium from zinc ores, or extracting rhenium from molybdenum ores. We don't have indium mines or rhenium mines, they're extracted as by-products from other deposits.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-07-27T09:17:03.990" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="11938" PostTypeId="2" ParentId="10505" CreationDate="2017-07-27T11:57:27.267" Score="1" Body="&lt;p&gt;If the pumping well is partially penetrating in the aquifer or the source above the aquifer (e.g., unconfined aquifer, leaky aquifer, under the stream), the vertical flow should be accounted. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The groundwater equation like Thies' solution is not considering the vertical flow. Incorporating the vertical flow would change the governing equation (P.D.E.) form including the vertical hydraulic conductivity. Lots of papers have shown the solution form for considering that. &lt;/p&gt;&#xA;" OwnerUserId="10656" LastActivityDate="2017-07-27T11:57:27.267" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11939" PostTypeId="2" ParentId="11930" CreationDate="2017-07-27T12:22:11.203" Score="4" Body="&lt;p&gt;Sulphur/sulphides in coal may be one of the causes of self combustion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A slight diversion - in some metal sulphide mines, such as copper, at high level of sulphides in the ore, the sulphides can oxidize thus creating sulphide fires. If a lot of dry dust is produced during stope blasts, during the mining process, sometimes the  sulphide dust can cause a secondary, unwanted, explosion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most coal deposits contain sulphides/sulphur. Most lignite (brown coal, also low quality or low grade coal) deposits are nearer the surface, thus if lignite has lots of sulphur &amp;amp; it oxidizes with atmospheric oxygen combustion can occur.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-07-27T12:22:11.203" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="11940" PostTypeId="2" ParentId="11930" CreationDate="2017-07-27T12:57:03.117" Score="4" Body="&lt;p&gt;Reference [6] under that &lt;a href=&quot;https://en.wikipedia.org/wiki/Spontaneous_combustion#Coal&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia article on spontaneous combustion&lt;/a&gt; gives you some answers:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;The Fire Below: Spontaneous Combustion In Coal&quot;. DOE/EH-0320, Issue No. 93-4. US Department of Energy. May 1993&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How Coal Self-Ignites&lt;br /&gt;&lt;br /&gt;&#xA;  The coal's temperature begins to climb above ambient.  At about 150-300&#xA;  degrees F, it begins to give off minute, but measurable, quantities of&#xA;  gas--aerosols, hydrogen, and CO(2)--precursors of combustion.  As the&#xA;  temperature increases further--at about 600-700 degrees F--relatively,&#xA;  large, visible particulates are emitted.  Soon, as the heating rate&#xA;  increases in intensity to about 750-800 degrees F, incipient combustion,&#xA;  and ultimately self-ignition and flame, will occur.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Spontaneous combustion has long been recognized as a fire hazard in stored&#xA;  coal.  Spontaneous combustion fires usually begin as &quot;hot spots&quot; deep&#xA;  within the reserve of coal.  The hot spots appear when coal absorbs oxygen&#xA;  from the air.  Heat generated by the oxidation then initiated the fire.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The list of recommendations towards the end of that article specifically mentions as contributing factors: &lt;em&gt;sulphur content&lt;/em&gt;, &lt;em&gt;moisture&lt;/em&gt;, &lt;em&gt;age of the mined coal&lt;/em&gt; and the obvious &lt;em&gt;availability of oxygen&lt;/em&gt; and &lt;em&gt;ambient temperature&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Don't forget to read the &lt;em&gt;A Lesson Learned from the Titanic&lt;/em&gt; at the end, describing how in April 1912, their bunker coal was on fire 'from the day we put out of Southhampton until we hit the iceberg'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think it is crucial to note that the tiniest amount of oxidation will lead to a rise in temperature, accelerating the process exponentially.&lt;/p&gt;&#xA;" OwnerUserId="595" LastActivityDate="2017-07-27T12:57:03.117" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="11941" PostTypeId="1" AcceptedAnswerId="11943" CreationDate="2017-07-27T14:14:59.030" Score="1" ViewCount="423" Body="&lt;p&gt;&lt;strong&gt;Purpose of my question:&lt;/strong&gt;&#xA;I create program to calculate solar radiation and I need to calculate radius between sun and earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The based on book &quot;Guide to HTML, JavaScript and PHP&quot;&#xA;For Scientists and Engineers, By David R. Brooks. The code is derived from this &lt;a href=&quot;http://www.instesre.org/Solar/BirdModelNew.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt; which is a calculator. I edited the code to C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Radius calculation&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In my code the radius calculation is defined as&#xA;&lt;code&gt;o-&amp;gt;R =1.000001018*(1.0-e*e)/(1.0+e*cos(f));&lt;/code&gt;&#xA;where &lt;em&gt;e&lt;/em&gt; - eccentricity of the earth's orbit:&#xA;      &lt;em&gt;f&lt;/em&gt;- true anomaly of the sun:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;void getSolarPosition(INPUTS * i, SOLPOS *o) {&#xA;if ( !i-&amp;gt;JulianDate )&#xA;   i-&amp;gt;JulianDate = getJulianDate(i); // date must be set to calculate Julian Date&#xA;double degRad = 0.017453292519943295769236907684886; // PI/180.0&#xA;// 2451545.0 - January 1, 2000, at 12:00:00 UT&#xA;double T=( i-&amp;gt;JulianDate-2451545.0)/36525.0;&#xA;&#xA;// L0 - geometric mean longitude of the sun:&#xA;double L0=280.46645+36000.76983*T+0.0003032*T*T;&#xA;// M - Mean anomaly of the sun:&#xA;double M = 357.52910+35999.05030*T-0.0001559*T*T-0.00000048*T*T*T;&#xA;&#xA;double M_rad = M * degRad;&#xA;// e - eccentricity of the earth's orbit:&#xA;double e=0.016708617-0.000042037*T-0.0000001236*T*T;&#xA;// C - sun's center&#xA;double C=(1.914600-0.004817*T-0.000014*T*T) * sin(M_rad)&#xA;        +(0.019993-0.000101*T)*sin(2.*M_rad)+0.000290*sin(3.*M_rad);&#xA;double L_save=(L0+C)/360.;&#xA;// L_true - True longitude of the sun&#xA;double L_true;&#xA;if (L_save &amp;lt; 0.)&#xA;   L_true = (L0+C) - ceil(L_save)*360.;&#xA;else&#xA;   L_true = (L0+C) - floor(L_save)*360.;&#xA;if (L_true &amp;lt; 0.) L_true+=360.;&#xA;// f - true anomaly of the sun:&#xA;double  f = M_rad + C * degRad;&#xA;// Earth-sun distance:&#xA;o-&amp;gt;R =1.000001018*(1.0-e*e)/(1.0+e*cos(f));&#xA;// Sidereal time (Theta0)&#xA;double Sidereal_time=280.46061837+ &#xA;  360.98564736629*( i-&amp;gt;JulianDate-2451545.) + &#xA;  0.000387933*T*T - T*T*T/38710000.;&#xA;// Replacement code for Sidereal=fmod(Sidereal,360.)&#xA;double S_save=Sidereal_time/360.;&#xA;if (S_save &amp;lt; 0.) Sidereal_time=Sidereal_time-ceil(S_save)*360.;&#xA;   else Sidereal_time=Sidereal_time-floor(S_save)*360.;&#xA;&#xA;if (Sidereal_time &amp;lt; 0.) Sidereal_time+=360.;&#xA;&#xA;// Obliquity - (Axial tilt)&#xA;o-&amp;gt;obliquity=23.0+26./60.+21.448/3600.-46.8150/3600.*T-0.00059/3600.*T*T + 0.001813/3600.*T*T*T;&#xA;&#xA;// right_ascension: tan(alpha)&#xA;o-&amp;gt;right_ascension = atan2(sin(L_true*degRad)*cos( o-&amp;gt;obliquity*degRad ),&#xA;                                                   cos(L_true*degRad));&#xA;// declination: sin(delta)&#xA;o-&amp;gt;declination = asin(sin( o-&amp;gt;obliquity*degRad )*sin(L_true*degRad));&#xA;// hour angle H of the sun with respect to the observer's longitude Lobs&#xA;o-&amp;gt;hour_angle=Sidereal_time + i-&amp;gt;lon - o-&amp;gt;right_ascension / degRad;&#xA;o-&amp;gt;elevation = (asin(sin( i-&amp;gt;lat*degRad )*sin( o-&amp;gt;declination)+cos(i-&amp;gt;lat*degRad)*cos( o-&amp;gt;declination )*cos( o-&amp;gt;hour_angle*degRad )))/degRad;&#xA;// Solar Zenit Angle&#xA;o-&amp;gt;Z = 90.-o-&amp;gt;elevation;&#xA;}&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;This is function to calculate solar position. It works exactly the same as Bird and Hulstrom's Solar Irradiance Model refered the calculator (see link above). Here I use &lt;em&gt;i&lt;/em&gt; input object where input data are are saved and &lt;em&gt;o&lt;/em&gt; ouput object where the calculated data regarding solar position are saved after they are calculated. atan2 - Returns the principal value of the arc tangent of y/x, expressed in radians (whatever it means, this is taken from C/C++ manual - &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;I am not mathematician&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;). Ceil rounds up; floor rounds down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem is that if I set old date like&#xA;&lt;strong&gt;1849&lt;/strong&gt;/06/31 11:15 The Solar constant corrected to Radius does not fit the &lt;a href=&quot;http://lasp.colorado.edu/lisird/tsi/historical_tsi.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;historical records&lt;/a&gt;. In the case the result would 1322.3 be for SolConst 1367. Which is crazy. According historical data it should be 1361.035. So I expect the radius is wrong calculated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth/Sun distance correction is made in another function to calculate solar radiation. The code:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;// Earth/sun distance correction, Rsq = 1/R^2&#xA;// double Rsq=(1.00011+0.034221*cos(6.28318*(d-1)/365)+0.00128*sin(6.28318*(d-1)/365)+0.000719*cos(2*(6.28318*(d-1)/365))+0.000077*sin(2*(6.28318*(d-1)/365)));&#xA;    double Rsq=1.0/ (solpos.R*solpos.R) ;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;I would like to ask you:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) where can I get historical records of the sun-earth radius&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) what is wrong with this formula or this calculation? Can you suggest better formula?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit:&#xA;I add the code needed to calculate radiation and solar constant correction.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;void getSolRadBird(INPUTS i, SOLPOS solpos, SOLRAD * o)&#xA;{&#xA;double degRad = 0.017453292519943295769236907684886;&#xA;// relative air mass&#xA;double AM=1./(cos( solpos.Z*degRad )+0.15*pow(93.885-solpos.Z,-1.25));&#xA;double AMp=AM*i.sitePressure/1013.;&#xA;// Rayleigh&#xA;double Tr=exp(-0.0903*pow(AMp,0.84)*(1+AMp-pow(AMp,1.01)));&#xA;// ozone&#xA;double Ozm=i.ozone*AM;&#xA;double Toz=1.-0.1611*Ozm*pow(1.+139.48*Ozm,-0.3035)-0.002715*Ozm/(1.+0.044*Ozm+0.0003*pow(Ozm,2.));&#xA;// mixed gases&#xA;double Tm=exp(-0.0127*pow(AMp,0.26));&#xA;// water vapor&#xA;double Wm=AM * i.water;&#xA;// total water vapor&#xA;double Tw=1.-2.4959*Wm/((1.+pow(79.034*Wm,0.6828))+6.385*Wm);&#xA;// daily turbidity&#xA;// Ta5=A*sin((Dan-B)*PI/180.)+C; aerosol optical depth at 500 nm&#xA;// Ta3=Ta5+0.1;&#xA;double Ta5=i.AOT500;&#xA;double Ta3=i.AOT380;&#xA;double Tau=0.2758*Ta3+0.35*Ta5;&#xA;double Ta=exp((-pow(Tau,0.873))*(1.+Tau-(pow(Tau,0.7088)))*pow(AM,0.9108));&#xA;&#xA;double TAA=1.-0.1*(1.-AM+pow(AM,1.06))*(1.-Ta);&#xA;double TAs=Ta/TAA;&#xA;double Rs=0.0685+(1.-0.84)*(1.-TAs);&#xA;// clear irradiance&#xA;double Io=i.SolConst;&#xA;// direct&#xA;// Earth/sun distance correction, Rsq = 1/R^2&#xA;// double d=f.doy;&#xA;// double Rsq=(1.00011+0.034221*cos(6.28318*(d-1)/365)+0.00128*sin(6.28318*(d-1)/365)+0.000719*cos(2*(6.28318*(d-1)/365))+0.000077*sin(2*(6.28318*(d-1)/365)));&#xA;double Rsq=1.0/ (solpos.R*solpos.R) ;&#xA;//alert(&quot;R= &quot;+Rsq);&#xA;double Id=Rsq*Io*.9662*Tr*Toz*Tm*Tw*Ta;&#xA;// direct on horizontal surface&#xA;double Idh=Id*cos(solpos.Z*degRad);&#xA;// diffuse (scattered)&#xA;double Ias=0.79*Io*cos(solpos.Z*degRad)*Toz*Tm*Tw*TAA;&#xA;Ias=Ias*(0.5*(1.-Tr)+0.85*(1.-TAs))/(1.-AM+pow(AM,1.02));&#xA;// total dif + dir on horizontal&#xA;double Itot=(Idh+Ias)/(1.-i.albedo*Rs);&#xA;double Idif=Itot-Idh;&#xA;&#xA;// Save the values&#xA;o-&amp;gt;air_m = AM;&#xA;o-&amp;gt;direct = Idh;&#xA;o-&amp;gt;diffuse = Idif;&#xA;o-&amp;gt;total = Itot;&#xA;o-&amp;gt;S_corrected = Rsq*Io;&#xA;}&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="9637" LastEditorUserId="9637" LastEditDate="2017-07-27T16:23:48.130" LastActivityDate="2018-01-20T20:58:55.933" Title="Earth's orbit and historical sun-earth distance" Tags="|earth-history|astronomy|orbit|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="11942" PostTypeId="1" CreationDate="2017-07-27T15:39:29.003" Score="1" ViewCount="53" Body="&lt;p&gt;-I study the near-surface via seismic reflection surveying with shear-waves. I know that effective stress strongly influences the velocity behavior of any body wave in the &lt;strong&gt;near-surface&lt;/strong&gt; (5 - 50 m). My question is this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*Does effective stress influence SH (horizontally-polarized) or SV (vertically-polarized) shear-waves more? If you have an answer to this, please provide a citation/reference. Thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2017-07-27T15:39:29.003" Title="Shear-Waves and Stress" Tags="|seismic|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="11943" PostTypeId="2" ParentId="11941" CreationDate="2017-07-27T18:20:36.777" Score="3" Body="&lt;p&gt;This doesn't answer your question entirely, but if by &quot;sun-earth radius&quot; you mean the distance between the Earth and the Sun, you can visit &lt;a href=&quot;https://ssd.jpl.nasa.gov/?horizons&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://ssd.jpl.nasa.gov/?horizons&lt;/a&gt; with these settings:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DtsQK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DtsQK.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;to see that the length of the Earth's semimajor axis (the &quot;A&quot; value in each row) doesn't change much over the years (it remains very close to 1 AU, as expected).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the semimajor axis is only the &quot;average&quot; distance from the Sun for a given year, which may not be what you want.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you use these settings:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wcAp8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wcAp8.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;you can see the actual coordinates of the Earth as viewed from the Sun. From these, you can either compute the distance yourself, or you can look at the &quot;LT&quot; value which is light travel time, and thus gives the distance in light days. Note that I intentionally chose the odd interval of 500 days to demonstrate how the Sun's distance changes during the year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, these are &quot;computed&quot; distances, not actually historical records. However, given the inaccuracy of measuring distance to the Sun historically, the computed numbers are probably more accurate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This question is fine here, but you may want to visit astronomy.stackexchange.com if you have other questions that are more directly based on astronomy.&lt;/p&gt;&#xA;" OwnerDisplayName="user967" LastEditorDisplayName="user967" LastEditDate="2017-07-28T15:18:18.133" LastActivityDate="2017-07-28T15:18:18.133" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="11945" PostTypeId="2" ParentId="11930" CreationDate="2017-07-27T23:17:45.967" Score="2" Body="&lt;p&gt;Coal, which is essentially pure carbon, &lt;strong&gt;slowly oxidizes&lt;/strong&gt;, it is the same reaction as it burning just much slower. &#xA;&lt;strong&gt;This is the &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S036012850300042X&quot; rel=&quot;nofollow noreferrer&quot;&gt;major&lt;/a&gt; source of heat for self-heating of coal&lt;/strong&gt;. &#xA;Many things that will burn will also slowly oxidize under normal temperatures, it is just not a sustained chain reaction that a fire is. Since this is weak slow process there is a large variety of &lt;a href=&quot;http://Oxocarbon&quot; rel=&quot;nofollow noreferrer&quot;&gt;oxocarbons&lt;/a&gt; that can be produced from this, some of which can contribute to more rapid heating the right circumstances. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2017-07-28T03:56:57.390" LastActivityDate="2017-07-28T03:56:57.390" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="11947" PostTypeId="2" ParentId="10728" CreationDate="2017-07-28T12:09:03.040" Score="3" Body="&lt;p&gt;As an alternative to Convergent Cross Mapping (CCM), the recent &lt;a href=&quot;https://github.com/jakobrunge/tigramite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tigramite&lt;/a&gt; is a fast python library for causal discovery that promises to ...&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... outperforms current approaches in detection power and scales up to high-dimensional datasets. It overcomes detection biases, especially when strong autocorrelations are present, and allows ranking associations in large-scale analyses by their causal strength.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The paper introducing the method contains a real data application on an atmospheric and climatic dataset:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://arxiv.org/abs/1702.07007&quot; rel=&quot;nofollow noreferrer&quot;&gt;Runge, Jakob, Dino Sejdinovic, and Seth Flaxman. “Detecting Causal Associations in Large Nonlinear Time Series Datasets.” arXiv:1702.07007 [Physics, Stat], February 22, 2017. http://arxiv.org/abs/1702.07007.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At first sight the difference with CCM would be:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;CCM is a deterministic approach as it test if to time series are related to the same hypothetical attractor while Tigramite test for statistical dependence between delays. &lt;/li&gt;&#xA;&lt;li&gt;CCM is a pairwise approach while Tigramite is faster and easily applied to larger database.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Those might be complementary.&lt;/p&gt;&#xA;" OwnerUserId="3363" LastActivityDate="2017-07-28T12:09:03.040" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11948" PostTypeId="2" ParentId="11933" CreationDate="2017-07-28T15:22:33.217" Score="0" Body="&lt;p&gt;Nat gas is the lowest cost source. The He ( alpha particles) is from decay of elements from silver and up ( atomic weight &gt; 106 per Wiki ). For a price it can be extracted from air. For example atmospheric argon is a significant nuisance in chemical plants that use air as a raw material , such as ammonia production. The recycle stream must have a constant bleed to prevent excessive concentration of Ar. I don't believe they analyzed for He . The bleed for Ar must have also reduced the He. &lt;/p&gt;&#xA;" OwnerUserId="8409" LastEditorUserId="8409" LastEditDate="2017-07-28T20:17:31.270" LastActivityDate="2017-07-28T20:17:31.270" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="11949" PostTypeId="1" AcceptedAnswerId="11961" CreationDate="2017-07-28T22:49:45.070" Score="3" ViewCount="389" Body="&lt;p&gt;I am interested in the area draining into and affecting a particular lake. Delineating this drainage basin, should I use the lake's inlet or outlet to best capture the relevant drainage basin? I think including the lake is valuable in this exercise, as events on or in the lake itself also affect the lake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd think outlet, but want to double check with you all. To complicate things, most lakes have more than one inlet and outlet. I guess I'd go with the lowest outlet in order to avoid missing any land which may drain into the lake.&lt;/p&gt;&#xA;" OwnerUserId="4789" LastEditorUserId="4789" LastEditDate="2017-08-03T12:46:13.733" LastActivityDate="2017-08-03T12:46:13.733" Title="To delineate the drainage basin for a lake, would the pour point be the inlet or the outlet?" Tags="|hydrology|gis|watershed|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="11950" PostTypeId="1" AcceptedAnswerId="12492" CreationDate="2017-07-29T00:59:00.723" Score="1" ViewCount="132" Body="&lt;p&gt;*One of the fundamental assumptions of the convolutional model (and subsequently a lot of deconvolution methods) is that reflectivity is a purely random (or &quot;white&quot;) process. Overall, the only predictable part of a seismogram is that of the source wavelet. Now, reflectivity is NOT purely random. Despite this, the convolutional model is still a very useful tool.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-My question(s) is this: what if reflectivity is somehow predictable? What would that (for lack of a better word/phrase) &lt;em&gt;look&lt;/em&gt; like? How would that jeopardize the usefulness of different deconvolution methods...? Thanks in advance to anyone who can help clarify this.&lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2017-10-17T17:02:05.207" Title="Seismic Reflectivity and Fractal (Random) Behavior" Tags="|seismic|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="11954" PostTypeId="1" AcceptedAnswerId="12018" CreationDate="2017-07-29T18:52:37.277" Score="1" ViewCount="66" Body="&lt;p&gt;Are there planets that lack mountains or have constrained availablilty of solids. For example a planet that has clay but not more solid stones like normal stones. The direct reason why I wonder is because I started to wonder if there existed planets where one would have to build less solid houses then at the earth due to the solids available if a person would build a house on that planet hypothetically spoken. It would be really nice with a detailed answer of what solids another planet would lack and how it constraints the housings that could be built on that planet in terms of solidness.&lt;/p&gt;&#xA;" OwnerUserId="10668" LastEditorUserId="10668" LastEditDate="2017-07-29T19:16:23.053" LastActivityDate="2017-08-07T01:31:05.620" Title="Mountains and solids on other planets" Tags="|planetary-formation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="11955" PostTypeId="2" ParentId="10876" CreationDate="2017-07-29T19:18:20.357" Score="10" Body="&lt;p&gt;There are many factors involved, so this is worth yet another answer. At the end of his/her &lt;a href=&quot;https://earthscience.stackexchange.com/a/10880/595&quot;&gt;answer&lt;/a&gt; &lt;em&gt;aretxabaleta&lt;/em&gt; states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In general, the areas near the poles have a negative trend (sea level is dropping, not rising) because of the Glacial Isostatic Adjustment (GIA) as the crust is still rebounding from the previous glaciation. In mid-latitudes, on the other hand the sea level rise rates are maximum&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In those locations however, there is a stronger effect:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ice masses themselves exert a large gravitational pull on the surrounding water, resulting in a &lt;strong&gt;lowering&lt;/strong&gt; of the sea level around those masses (Greenland, Antarctica) when the ice melts.&lt;br /&gt;&#xA;This may seem counter-intuitive, and is best explained by looking at what happens when the ice masses grow:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The gravitation of the growing mass pulls water towards it. The resulting sea level rise on the edges of the ice mass is therefore &lt;em&gt;larger&lt;/em&gt; than the eustatic (global, uniform, across the world) sea level decrease that occurs because of the water moving into the ice. The effect is that near the ice mass, sea level actually rises, and far away it falls faster than 'expected'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the ice melts the reverse happens: sea level close to the ice mass will drop, sea level far away will rise more than 'expected'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To give this some actual numbers:&lt;br /&gt;&#xA;The eustatic sea level rise corresponding to the melting of the Greenland and West Antarctic ice caps is both approx. 6 meters.&lt;br /&gt;&#xA;Here in Europe (I live in the Netherlands) however, the Greenland melt would 'only' result in approx. 3 meters rise, because that is relatively close, but the West Antarctic melt would result in something like 8-9 meters extra water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This picture shows the &lt;em&gt;relative&lt;/em&gt; effect calculated for water running of West Antarctica. You should read the numbers as a multiplication factor to apply to amount of sea level rise in the case of a uniform distribution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vlbI8.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vlbI8.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Sea level change associated with a uniform thinning of the West Antarctic Ice Sheet (WAIS). Their result, reproduced in Fig. 1(a), was normalized by the eustatic sea level change (i.e. the change computed assuming that the meltwater entered the present-day ocean uniformly). [...] The map shows a peak sea level rise greater than 25 per cent above the eustatic value in the north Pacific and more than 20 per cent above the eustatic in the north Atlantic and Indian Oceans. In addition, the sea level fall is greater than five times the eustatic amplitude in the ocean adjacent to the West Antarctic.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://academic.oup.com/gji/article/187/2/729/571441&quot; rel=&quot;noreferrer&quot;&gt;On the robustness of predictions of sea level fingerprints&lt;/a&gt;&lt;br /&gt;&#xA;J. X. Mitrovica, N. Gomez, E. Morrow, C. Hay, K. Latychev, M. E. Tamisiea&lt;br /&gt;&#xA;14 October 2011&lt;br /&gt;&#xA;DOI: 10.1111/j.1365-246X.2011.05090.x  &lt;/p&gt;&#xA;" OwnerUserId="595" LastActivityDate="2017-07-29T19:18:20.357" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="11957" PostTypeId="1" AcceptedAnswerId="11960" CreationDate="2017-07-30T12:29:09.240" Score="1" ViewCount="812" Body="&lt;p&gt;My question concerns the depression cone of a pumping well in a confined aquifer: Say the transmissivity of the aquifer is 1200 m^2/day how will the cone change if the transmissivity is 600 m^2/day? All the aquifers parameters stay constant in both scenarios and so is the pumping rate (say- 300 cm/hr).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main interest is what happens to the radius of influence (where there will be no change in head from the aquifers regional head)? and also what happens to the head at the well it self?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks, Asher&lt;/p&gt;&#xA;" OwnerUserId="10671" LastActivityDate="2017-07-30T20:21:09.917" Title="Hydrology - Depression cone VS transmissivity" Tags="|hydrology|groundwater|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="11958" PostTypeId="2" ParentId="10420" CreationDate="2017-07-30T16:28:06.677" Score="7" Body="&lt;p&gt;Rain in a climate such as Ireland is most often stratiform. That is, it is created when moist air is lifted by a front, or by divergence in the upper troposphere. Thunderstorms involve buoyant air, which rises on its own due to its being warmer than its surroundings. Typically solar radiation is involved in heating the surface such that the air near it warms and becomes buoyant. That is more common in lower latitudes and locations that are typically sunny.&lt;/p&gt;&#xA;" OwnerUserId="10672" LastActivityDate="2017-07-30T16:28:06.677" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="11959" PostTypeId="1" CreationDate="2017-07-30T18:03:01.110" Score="2" ViewCount="36" Body="&lt;p&gt;I know of two live video channels showing live feeds of rover dives:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://oceanexplorer.noaa.gov/okeanos/media/exstream/exstream.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Okeanos Explorer&lt;/a&gt; for dives with the NOAA Ship Okeanos Explorer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://nautiluslive.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nautilus live&lt;/a&gt; for dives from the Nautilus, operated by the Ocean Exploration Trust.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone know others?&lt;/p&gt;&#xA;" OwnerUserId="595" LastActivityDate="2019-07-10T00:43:20.847" Title="Live video feeds for submarine ROVs?" Tags="|oceanography|sea-floor|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11960" PostTypeId="2" ParentId="11957" CreationDate="2017-07-30T20:21:09.917" Score="3" Body="&lt;p&gt;Based on the Theis equation, increasing the transmissivity will increase the radius of influence and decrease the total drawdown.  Drawdown is directly proportional to the pumping rate and inversely proportional to aquifer transmissivity and storativity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$s = \frac{Q}{4T\pi}\int_u^\infty \frac{e^{-y}}y dy$$&#xA;and $$u = \frac{r^{2}s}{4Tt}$$&#xA;Where s is drawdown, r is radius from well, t is time, T is transmissivity, Q is pumping rate, and u is the well function.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Applying this equation, you can produce plots like this:&lt;a href=&quot;https://i.stack.imgur.com/UUajW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UUajW.jpg&quot; alt=&quot;cone of depression with well at 0; note the log-log scales&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/tsJn5.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tsJn5.jpg&quot; alt=&quot;radius of influence as a function of T&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;for these plots, I used Q = 500, S = 0.01, and t = 4&lt;/p&gt;&#xA;" OwnerUserId="510" LastActivityDate="2017-07-30T20:21:09.917" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="11961" PostTypeId="2" ParentId="11949" CreationDate="2017-07-30T22:01:31.723" Score="2" Body="&lt;p&gt;I think there are a few things to consider. First, a drainage basin is defined as the area upstream of the point to which all precipitation converges. Flow does not converge at the outlet - flow converges at the lake. Outlets don't contain any additional information of the upstream area draining into the lake. This implies that to find the area draining &lt;em&gt;into a lake&lt;/em&gt;, you would necessarily have to proceed beginning from &lt;em&gt;each and every inlet&lt;/em&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's another way to see this. Approximately 20% of all land drains to lakes with no outlets. These are referred to as &lt;em&gt;endorheic&lt;/em&gt; lakes or &lt;em&gt;endorheic&lt;/em&gt; basins. Even though there is no outlet, there is absolutely still a definable drainage basin area.&lt;/p&gt;&#xA;" OwnerUserId="6221" LastActivityDate="2017-07-30T22:01:31.723" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="11962" PostTypeId="1" CreationDate="2017-07-30T23:12:57.640" Score="-1" ViewCount="85" Body="&lt;p&gt;What are some examples of fossil sites where land-living fossils end up in the sea, off the coast-line of an island?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ygh8q.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ygh8q.png&quot; alt=&quot;fossil site example&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="10675" LastActivityDate="2017-07-31T03:10:11.453" Title="What are some regions where land-living island animals have left fossil records within the sea, of the coast of the island?" Tags="|geology|paleontology|fossils|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="11963" PostTypeId="1" CreationDate="2017-07-31T00:53:20.443" Score="5" ViewCount="559" Body="&lt;p&gt;Suppose that I want to calculate the transport across a certain transect (green line) from the outputs of an ocean numerical model. The model has the $u$ values at the center of the grids (crosses) and the $v$ values at the corners (circles), as it uses a C-grid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NVXSM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NVXSM.jpg&quot; alt=&quot;scheme&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Should I use the velocity values closest to the transect? Should I average the values at the corners? Interpolate?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Side question: does anyone know some Matlab toolbox to analyze numerical model outputs?&lt;/p&gt;&#xA;" OwnerUserId="6001" LastEditorUserId="111" LastEditDate="2017-07-31T16:16:29.550" LastActivityDate="2017-08-04T20:25:51.427" Title="correct way to calculate transport through a section in an ocean numerical model" Tags="|numerical-modelling|data-analysis|matlab|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="11964" PostTypeId="2" ParentId="11962" CreationDate="2017-07-31T03:10:11.453" Score="3" Body="&lt;p&gt;Two sites in Australia, at opposite ends of the continent, that have such fossils are Cable Beach in &lt;a href=&quot;https://en.wikipedia.org/wiki/Broome,_Western_Australia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Broome&lt;/a&gt;, Western Australia (in the north west of the Australia) and &lt;a href=&quot;https://en.wikipedia.org/wiki/Dinosaur_Cove&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dinosaur Cove&lt;/a&gt;, in Victoria (in the south east of Australia).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fossils in Broome can only be seen at low tide and are of dinosaur footprints from the Cretaceous period, about 130 million years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Dinosaur Cove has yielded bones that lead to the discovery of  &lt;a href=&quot;https://en.wikipedia.org/wiki/Hypsilophodont&quot; rel=&quot;nofollow noreferrer&quot;&gt;hypsilophodontid&lt;/a&gt;-like dinosaurs as &lt;a href=&quot;https://en.wikipedia.org/wiki/Leaellynasaura&quot; rel=&quot;nofollow noreferrer&quot;&gt;Leaellynasaura&lt;/a&gt; amicagraphica and &lt;a href=&quot;https://en.wikipedia.org/wiki/Atlascopcosaurus&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atlascopcosaurus&lt;/a&gt; loadsi, and a &lt;a href=&quot;https://en.wikipedia.org/wiki/Coelurosauria&quot; rel=&quot;nofollow noreferrer&quot;&gt;Coelurosaur&lt;/a&gt;, as well as fragments of what may be a &lt;a href=&quot;https://en.wikipedia.org/wiki/Caenagnathidae&quot; rel=&quot;nofollow noreferrer&quot;&gt;caenagnathid&lt;/a&gt; (relatives of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Oviraptor&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oviraptors&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other information can be obtained from:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://wkfl.asn.au/nature/dinosaurs.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Broome dinosaurs&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.theguardian.com/science/2016/sep/07/dinosaur-footprints-from-cretaceous-period-uncovered-on-broomes-cable-beach&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cretaceous dinosaur footprints uncovered on Western Australian&#xA;beach&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://dinosaurcoveaustralianfossilsite.weebly.com/types-of-fossils.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dinosaur Cove&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-07-31T03:10:11.453" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="11965" PostTypeId="1" AcceptedAnswerId="11968" CreationDate="2017-07-31T07:26:49.163" Score="4" ViewCount="1163" Body="&lt;p&gt;Which model is a good starting point for predicting precipitation (rain) for 24 hours in advance? I looked at Kalnay's &lt;em&gt;Atmospheric modeling, data assimilation and predictability&lt;/em&gt;, and Holton's &lt;em&gt;An Introduction to Dynamic Meteorology&lt;/em&gt; as well as various other sources. These are great references but I could not figure out which part I could use to compute what I needed. It seems there are governing equations which are solved numerically, the output is used for a prediction. I am knowledgeable on numerically solving ODEs, PDEs, and am familiar with Matlab, Python, but there aren't any references that I could find providing clear formula -&gt; data -&gt; code -&gt; output.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most talked about model with clear solution is the Barotropic Vorticity Equation, which, I believe, models wind and pressure. This model was proposed by Charney, Fjortoft and von Neumann during the 50s, and solved with a computer, the results are recreated by Peter Lynch on 2008 (Matlab code &lt;a href=&quot;https://maths.ucd.ie/~plynch/eniac/&quot; rel=&quot;nofollow noreferrer&quot;&gt;available&lt;/a&gt;). Could this model be used for rainfall prediction? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If one has to dig in the basic equations, which part of the governing equations should I focus on? Any pointers, references with running code is most welcome.&lt;/p&gt;&#xA;" OwnerUserId="10677" LastEditorUserId="192" LastEditDate="2017-08-01T14:28:34.610" LastActivityDate="2017-08-02T08:55:20.083" Title="Predicting rainfall with governing equations" Tags="|meteorology|models|nwp|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="11966" PostTypeId="2" ParentId="11965" CreationDate="2017-07-31T10:41:46.030" Score="5" Body="&lt;p&gt;You could look further into how currently used &lt;a href=&quot;https://earthscience.stackexchange.com/questions/19/how-do-weather-models-work&quot;&gt;weather models actually work&lt;/a&gt;. If you want to do a prediction you will have to run a model which is not just as simple as your question would imply. There are actually many equations in parallel and that describe how motions in a grid behave. Sub grid phenomena like rain are parametrized also. Rain depends e.g. on moisture convergence and aerosol physics describing water droplet growth. This is really a broad question and I suggest you to ask another question if you want information about something more specific about forecasting.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastActivityDate="2017-07-31T10:41:46.030" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="11968" PostTypeId="2" ParentId="11965" CreationDate="2017-07-31T11:46:48.490" Score="12" Body="&lt;p&gt;The Barotropic vorticity equation is insufficient to model rain. Part of this is due to the word 'Barotropic,' which indicates a lack of thermal gradient. The other reason is that while vorticity is a useful quantity, it lacks explicit information on the atmospheric state.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://www4.ncsu.edu/~nwsfo/storage/training/jets/PE.html&quot; rel=&quot;noreferrer&quot;&gt;primitive equations&lt;/a&gt; are a system of partial differential equations that are used by most numerical weather prediction models to model various quantities. Rainfall rate is a parameterized variable, a diagnosed formula (or formulas) based on atmospheric state, based on research. Sometimes the results of the research can give wildly different answers given the same data, which is a weakness of parameterizations. The idea is to model the Reynolds-averaged primitive equations and intermittently invoke the parameterizations (including turbulence, radiation, cloud cover, and so on).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://rads.stackoverflow.com/amzn/click/0521126762&quot; rel=&quot;noreferrer&quot;&gt;Here&lt;/a&gt; is a good book that discusses parameterization schemes in general.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-07-31T11:46:48.490" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11970" PostTypeId="2" ParentId="11963" CreationDate="2017-07-31T16:16:19.010" Score="2" Body="&lt;p&gt;I have been using the routines in &lt;a href=&quot;https://github.com/nctoolbox/nctoolbox&quot; rel=&quot;nofollow noreferrer&quot;&gt;nctoolbox&lt;/a&gt; (also check &lt;a href=&quot;http://nctoolbox.github.io/nctoolbox/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;) that do all the slicing (vertical, horizontal, following a track).&#xA;The repository is in &lt;a href=&quot;https://github.com/nctoolbox/nctoolbox/tree/master/cdm/utilities/slicing&quot; rel=&quot;nofollow noreferrer&quot;&gt;GitHub&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The one you should looking at is &lt;a href=&quot;https://github.com/nctoolbox/nctoolbox/blob/master/cdm/utilities/slicing/vsliceg.m&quot; rel=&quot;nofollow noreferrer&quot;&gt;vsliceg.m&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can follow the logic there or develop your own.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2017-07-31T16:16:19.010" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="11972" PostTypeId="2" ParentId="11965" CreationDate="2017-08-01T14:00:55.357" Score="8" Body="&lt;p&gt;&lt;strong&gt;TL;DR:&lt;/strong&gt;&#xA;Global NWP models such as NCEP's GFS (free access) and ECMWF's IFS (restricted access) provide  forecasts at a horizontal scale of a few tens of kilometers every few hours. Starting from global NWP data, NCAR's WRF (free) can be used to produce results at a resolution of a few kilometers and stored every few minutes in time.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;I felt I could give some insights. This answer aims to provide further practical references regarding well-known NWP models. It centers on places to look at and what can be done with available resources. I will only briefly try to illustrate why the underlying physics can be seen as intrinsically complex.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Numerical Weather Prediction (NWP) models are interested in the system composed of the Earth's atmosphere and surface. This system encompasses physical features and processes with a wide range of scales: weather front across thousands of kilometers, cumulus spanning a few kilometers, soil layers varying over a few meters, rain drops smaller than a few millimeters in diameter, interactions with solar radiations shorter than a few micrometers in wavelength, ... The models work at a large scale, trying to resolve the movement of air masses by solving PDEs on a grid, and use physical parametrizations to work on the unresolved subgrid phenomenons. Due to the strong sensitivity to initial conditions, the quality of the input data is of paramount importance. This is especially true if fast varying localized features such as rain are of interest.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Global NWP models consider the entire system. They typically have a horizontal resolution of a few tens of kilometers. The initial conditions can come from many different sources of observations (weather radars, radiosoundings, buoys, satellites, airplanes, ...). The data assimilation job is hardly the easiest part and requires fetching all that data in the first place. Those two centers propose global NWP products:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the National Center for Environmental Prediction (NCEP) with the&#xA;&lt;a href=&quot;http://www.ncdc.noaa.gov/data-access/model-data/model-datasets/global-forcast-system-gfs/&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;NCEP Global Forecast System&quot;&gt;Global Forecast System&lt;/a&gt; (GFS). It is freely available and you can download whole datasets directly quite easily.&lt;/li&gt;&#xA;&lt;li&gt;the European Centre for Medium-Range Weather Forecasts (ECMWF) with the &lt;a href=&quot;http://apps.ecmwf.int/auth/login/&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;ECMWF Mars catalogue&quot;&gt;Integrated Forecast System&lt;/a&gt; (IFS). You need to register&#xA;to download data. Operational forecasts or analyses are not available&#xA;for free but re-analyses such as ERA-Interim are. The recent&#xA;resolution is better than GFS's. Among other ways to retrieve data,&#xA;besides the web interface, is a &lt;a href=&quot;http://software.ecmwf.int/wiki/display/WEBAPI/Accessing+ECMWF+data+servers+in+batch/&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;ECMWF. Accessing ECMWF data servers in batch&quot;&gt;python API&lt;/a&gt;. The &lt;a href=&quot;http://apps.ecmwf.int/codes/grib/param-db&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;ECMWF Parameter database&quot;&gt;IFS parameter&#xA;database&lt;/a&gt; can also be useful to visit. The &lt;a href=&quot;http://www.ecmwf.int/search/elibrary/part?title=part&amp;amp;secondary_title=43R1&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;ECMWF IFS Documentation&quot;&gt;IFS documentation&lt;/a&gt; is available online &lt;a href=&quot;http://www.ecmwf.int/search/elibrary/part?title=part&amp;amp;secondary_title=43R1&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;ECMWF IFS Documentation&quot;&gt;5&lt;/a&gt; and is a good entry point to understand&#xA;the constitutive equations and the rest. Look at &quot;Part IV Physical&#xA;Processes, Chapter 7: Clouds and large-scale precipitation&quot; if you&#xA;are interested in what they do for rain.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Regional NWP models can use global NWP data as initial and boundary conditions. Possibly the best-known freely available regional model is the National Center for Atmospheric Research (NCAR) &lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/download/get_source.html&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;NCAR: WRF Source Codes and Graphics Software Downloads&quot;&gt;Weather Research and Forecasting&lt;/a&gt; (WRF) model. Relevant downloads to run the model are the source code for WRFV3, WPS, and the static geographic data (a few GBs!). It has a &lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/OnLineTutorial/compilation_tutorial.php&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;NCAR. How to Compile WRF: The Complete Process&quot;&gt;comprehensive installation procedure&lt;/a&gt;, and the WRF tutorials and forums may help too. The &lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/docs/user_guide_V3/contents.html&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;NCAR. User’s Guides for the Advanced Research WRF (ARW) Modeling System, Version 3&quot;&gt;user's guide&lt;/a&gt; and the &lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/docs/arw_v3.pdf&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;NCAR. A Description of the Advanced Research WRF Version 3&quot;&gt;description of the physics&lt;/a&gt; are very interesting to look at besides the code. You can find the &lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/phys_references.html&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;NCAR. WRF Model Physics Options and  References&quot;&gt;original references&lt;/a&gt; for the implemented parametrizations, and many &lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/workshops/WS2010/presentations/Lectures/Microphysics10.pdf&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;NCAR. Microphysics Options in WRF&quot;&gt;presentations&lt;/a&gt; from their workshops (e.g. on the microphysics).  Speaking of the microphysics, looking at WRFV3/phys, you can find individual Fortran modules for some of the parametrization:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;code&gt;module_mp_kessler.F&lt;/code&gt; (~ 250 LOC) (vapor, rain, cloud water),&lt;/li&gt;&#xA;&lt;li&gt;&lt;code&gt;module_mp_lin.F&lt;/code&gt; (~ 3000 LOC) (vapor, rain, cloud water, cloud ice, snow, graupel).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So it might not be completely unreasonable to speak of ~1000 LOC for rain in NWP, but this would be ignoring the many other thousands LOC needed to run the rest of the physics. For the processing of the outputs many options are described in the manual, and you might be interested in &lt;a href=&quot;http://github.com/NCAR/wrf-python&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;NCAR. A collection of diagnostic and interpolation routines for use with output from the Weather Research and Forecasting (WRF-ARW) Model.&quot;&gt;some post-processing code in python&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In conclusion I think an accurate forecast for rain is unrealistic without the entire NWP machinery. For anybody to apply it by him/herself require to get acquainted with available datasets and softwares. With ~1000 LOC of python you can at least draft a framework around GFS/ECMWF data and WRF, and possibly some other work, that suits some of your needs/desires regarding rain forecasts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a side note, local/national weather services may otherwise have interesting products from their own models (some of them possibly free). Also, applications that do not actually require an accurate forecast (e.g. only valid on a statistical basis) can rely on other rain models outside of NWPs and use less input data (e.g. only long term rain rate measurements). Some &quot;rain cells&quot; models used in radioscience may fit this description.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;References&lt;/h2&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.ncdc.noaa.gov/data-access/model-data/model-datasets/global-forcast-system-gfs/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.ncdc.noaa.gov/data-access/model-data/model-datasets/global-forcast-system-gfs/&lt;/a&gt; &quot;NCEP Global Forecast System&quot;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://apps.ecmwf.int/auth/login/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://apps.ecmwf.int/auth/login/&lt;/a&gt; &quot;ECMWF Mars catalogue&quot;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://software.ecmwf.int/wiki/display/WEBAPI/Accessing+ECMWF+data+servers+in+batch/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://software.ecmwf.int/wiki/display/WEBAPI/Accessing+ECMWF+data+servers+in+batch/&lt;/a&gt; &quot;ECMWF. Accessing ECMWF data servers in batch&quot;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://apps.ecmwf.int/codes/grib/param-db&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://apps.ecmwf.int/codes/grib/param-db&lt;/a&gt; &quot;ECMWF Parameter database&quot;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.ecmwf.int/search/elibrary/part?title=part&amp;amp;secondary_title=43R1&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.ecmwf.int/search/elibrary/part?title=part&amp;amp;secondary_title=43R1&lt;/a&gt; &quot;ECMWF IFS Documentation&quot;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/download/get_source.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www2.mmm.ucar.edu/wrf/users/download/get_source.html&lt;/a&gt; &quot;NCAR: WRF Source Codes and Graphics Software Downloads&quot; &lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/OnLineTutorial/compilation_tutorial.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www2.mmm.ucar.edu/wrf/OnLineTutorial/compilation_tutorial.php&lt;/a&gt; &quot;NCAR. How to Compile WRF: The Complete Process&quot;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/docs/user_guide_V3/contents.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www2.mmm.ucar.edu/wrf/users/docs/user_guide_V3/contents.html&lt;/a&gt; &quot;NCAR. User’s Guides for the Advanced Research WRF (ARW) Modeling System, Version 3&quot;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/docs/arw_v3.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www2.mmm.ucar.edu/wrf/users/docs/arw_v3.pdf&lt;/a&gt; &quot;NCAR. A Description of the Advanced Research WRF Version 3&quot;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/phys_references.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www2.mmm.ucar.edu/wrf/users/phys_references.html&lt;/a&gt; &quot;NCAR. WRF Model Physics Options and  References&quot;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/workshops/WS2010/presentations/Lectures/Microphysics10.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www2.mmm.ucar.edu/wrf/users/workshops/WS2010/presentations/Lectures/Microphysics10.pdf&lt;/a&gt; &quot;NCAR. Microphysics Options in WRF&quot;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://github.com/NCAR/wrf-python&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://github.com/NCAR/wrf-python&lt;/a&gt; &quot;NCAR. A collection of diagnostic and interpolation routines for use with output from the Weather Research and Forecasting (WRF-ARW) Model.&quot;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="10687" LastEditorUserId="106" LastEditDate="2017-08-02T08:55:20.083" LastActivityDate="2017-08-02T08:55:20.083" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11973" PostTypeId="1" CreationDate="2017-08-01T20:09:30.067" Score="8" ViewCount="1885" Body="&lt;p&gt;I have heard artists talk about the unique quality of light near the sea, and now I live near the coast I want to know if there's any truth in it. Does being near the ocean affect light inland?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm in the UK, where it's not usually  clear blue skies; it's cloudy or partially cloudy (clouds may have an effect?).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've lived in a flattish region in the centre of the UK, and at the coast. I think it's brighter here, but I can't figure out &lt;em&gt;if&lt;/em&gt; it's a real difference. And Google is silent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've come up with possible explanations:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;It's purely psychological&lt;/li&gt;&#xA;&lt;li&gt;It's a side-effect of the big horizons making places feel lighter because more sky is visible&lt;/li&gt;&#xA;&lt;li&gt;Sunlight reflects off the sea, and the clouds scatter it back onto the land&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Is this real? If so, what's the mechanism and how far inland does the light penetrate?&lt;/p&gt;&#xA;" OwnerUserId="10691" LastActivityDate="2020-06-06T18:08:06.323" Title="Light at the coast - is it different?" Tags="|ocean|sun|coastal|light|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="11974" PostTypeId="2" ParentId="11923" CreationDate="2017-08-01T20:43:55.417" Score="2" Body="&lt;p&gt;Trade winds from a general easterly direction occur almost all of the time in the Caribbean and tropical Atlantic. A hurricane approaching from any direction except from the south would change the wind direction because winds spiral counterclockwise into the hurricane. For example, a hurricane approaching from the east would cause the wind direction to back to northerly, while one approaching from the west (very rare in the tropics before recurvature occurs) would cause the wind direction to veer to southerly. If a hurricane approached from a general southerly direction, the wind would remain generally easterly but would gradually increase in speed and gustiness. Hurricanes are often accompanied by anticlyclonic outflow at upper levels; this could be observed via the motion of cirrus clouds. &lt;/p&gt;&#xA;" OwnerUserId="8382" LastEditorUserId="8382" LastEditDate="2017-08-08T07:40:46.090" LastActivityDate="2017-08-08T07:40:46.090" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="11978" PostTypeId="1" AcceptedAnswerId="11997" CreationDate="2017-08-02T11:23:49.387" Score="2" ViewCount="124" Body="&lt;p&gt;I have this satellite derived sounding(T-phi gram) of a mountainous area and from what little I can make out it appears that probability of precipitation is almost negligible. Let us assume my model output for the same time predicted the rainfall event accurately that happened at the given time and TRMM satellite data was able to pick up the rainfall event as well. Is there something in the sounding diagram that I have displayed that can pick up the rainfall event as being  likely? I for one cannot make it out as  CAPE is zero and CIN is greater than 200. I obviously have a follow up question  - accuracy of satellite derived soundings in mountainous areas but that is for later. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/v4Iif.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/v4Iif.gif&quot; alt=&quot;Satellite derived sounding&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastActivityDate="2017-08-04T11:20:45.923" Title="T-phigram satellite derived sounding vs model output question" Tags="|convection|radiosounding|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="11981" PostTypeId="2" ParentId="11911" CreationDate="2017-08-03T00:45:33.730" Score="3" Body="&lt;p&gt;By your edit, it seems you are more interested in the &quot;big data&quot; side of the science. Model reanalyses contain large amounts of historical weather data, so that is a safe bet for ample amounts of data. &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/model-data/model-datasets&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOMADS&lt;/a&gt;, which is a service provided by the National Weather Service is a good resource for model data. There is another version of &lt;a href=&quot;http://nomads.ncep.noaa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOMADS&lt;/a&gt; for operational data; I'd recommend that. For generic data, &lt;a href=&quot;https://rda.ucar.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;RDA&lt;/a&gt; has data. NASA has a &lt;a href=&quot;https://disc.sci.gsfc.nasa.gov/datasets?page=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;server&lt;/a&gt; that also has a lot of data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can also generate your own weather data for prediction and the like, by using models like &lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/&quot; rel=&quot;nofollow noreferrer&quot;&gt;WRF&lt;/a&gt; or &lt;a href=&quot;https://www.ictp.it/research/esp/models/speedy.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;SPEEDY&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Departing from model data, you have observations, you can access ground-based observational datasets via &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/land-based-station-data/land-based-datasets&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCDC&lt;/a&gt;. NCDC also has &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/satellite-data/satellite-data-access-datasets&quot; rel=&quot;nofollow noreferrer&quot;&gt;satellite data&lt;/a&gt;, &lt;a href=&quot;https://www.ncdc.noaa.gov/nexradinv/&quot; rel=&quot;nofollow noreferrer&quot;&gt;radar data&lt;/a&gt;, and so on down the line (you don't need me to explore the site for you).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other countries have other datasets, though many come with a price. ECMWF, for example, has &lt;a href=&quot;https://www.ecmwf.int/en/research/climate-reanalysis&quot; rel=&quot;nofollow noreferrer&quot;&gt;reanalysis products&lt;/a&gt;, &lt;a href=&quot;https://www.ecmwf.int/en/forecasts/datasets/catalogue-ecmwf-real-time-products&quot; rel=&quot;nofollow noreferrer&quot;&gt;operational datasets&lt;/a&gt;, etc. The same is true for &lt;a href=&quot;http://ds.data.jma.go.jp/tcc/tcc/products/model/&quot; rel=&quot;nofollow noreferrer&quot;&gt;JMA&lt;/a&gt;, and other countries with their own weather service.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-08-03T00:45:33.730" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11982" PostTypeId="1" AcceptedAnswerId="11989" CreationDate="2017-08-03T09:05:47.880" Score="3" ViewCount="2602" Body="&lt;p&gt;I've got 4 different .txt files for longitude, latitude, wind speed and wind direction (so no U and V components of the wind). Is there any way to plot wind barbs from such a dataset?&lt;/p&gt;&#xA;" OwnerUserId="10670" LastEditorUserId="94" LastEditDate="2017-08-03T12:35:04.107" LastActivityDate="2017-08-03T15:52:13.670" Title="Plotting wind barbs in python (no U,V component)" Tags="|meteorology|atmosphere|wind|python|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="11983" PostTypeId="2" ParentId="11982" CreationDate="2017-08-03T11:04:02.380" Score="3" Body="&lt;p&gt;The data format you have (magnitude and direction) is usually referred to as &lt;em&gt;polar co-ordinates&lt;/em&gt;. The data format you need (horizontal and vertical offsets) is &lt;em&gt;Cartesian co-ordinates&lt;/em&gt;. There's plenty of good material on this online. For a friendly introduction, see e.g. &lt;a href=&quot;https://www.mathsisfun.com/polar-cartesian-coordinates.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this page on &quot;Math is Fun!&quot;&lt;/a&gt; (or your favourite high-school maths textbook).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Converting between the two systems involves a bit of simple trigonometry, and the exact formulae depend on how you're measuring the angle in your polar co-ordinates. Mathematicians tend to measure anticlockwise from the positive x axis in radians. Geoscientists usually measure clockwise from the positive y axis in degrees (like a compass bearing):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Je0l8.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Je0l8.gif&quot; alt=&quot;polar co-ordinates&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;Source: &lt;a href=&quot;https://kartoweb.itc.nl/geometrics/Coordinate%20systems/coordsys.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;kartoweb.itc.nl&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming that this is the convention used in your data, the conversion formulae are refreshingly straighforward.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$x = d\sin(\alpha)$&lt;br&gt;&#xA;$y = d\cos(\alpha)$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing to watch out for: like most programming languages, Python uses radians, not degrees, for its trigonometric functions. If your angles are in degrees, don't forget to run them through the &lt;code&gt;math.radians()&lt;/code&gt; function before taking sines and cosines!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Incidentally, having each measurement in a &lt;em&gt;separate&lt;/em&gt; text-file is probably a recipe for inconvenience and confusion. If I were you, I'd have &quot;combine measurements as columns in a single file&quot; as the first step in my processing workflow.&lt;/p&gt;&#xA;" OwnerUserId="94" LastActivityDate="2017-08-03T11:04:02.380" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11984" PostTypeId="1" CreationDate="2017-08-03T12:19:54.947" Score="7" ViewCount="981" Body="&lt;p&gt;So on a lot of maps of tectonic plates, it appears that India and Australia share a tectonic plate (hence the Indo-Australian plate). But in maps of Pangaea, India and Australia appear to have once shared a border. Since continents only move because the plates they sit on move, how is it that India and Australia have changed relative positions if they share a plate? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've looked around a lot online and I can't seem to find a specific reason, and my science teachers weren't much help either. Supposedly they once sat on separate plates, and diverged from each other, with a mid ocean ridge spewing out sea floor between them. If this is the case, how did they fuse together? Also, I believe that Australia is currently moving towards India as well. Do convection currents change direction?&lt;/p&gt;&#xA;" OwnerUserId="10707" LastActivityDate="2019-03-24T17:42:44.343" Title="How did Australia separate from India?" Tags="|plate-tectonics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11989" PostTypeId="2" ParentId="11982" CreationDate="2017-08-03T15:52:13.670" Score="3" Body="&lt;p&gt;I can answer this in two steps&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Calculate $u$ and $v$. This &lt;a href=&quot;http://tornado.sfsu.edu/geosciences/classes/m430/Wind/WindDirection.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;site&lt;/a&gt; has formulas for $u$ and $v$. They are as follows: $$u=-|\vec{v}|\sin(\frac{\pi}{180}\phi)$$ and $$v=-|\vec{v}|\cos(\frac{\pi}{180}\phi)$$&#xA;where $\phi$ is the wind direction in the meteorological system, and $|\vec{v}|$ is the wind speed.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Having calculated $u$ and $v$, you can plot the wind barbs by following the example found at &lt;a href=&quot;https://matplotlib.org/examples/pylab_examples/barb_demo.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; site. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-08-03T15:52:13.670" CommentCount="14" ContentLicense="CC BY-SA 3.0" />
  <row Id="11990" PostTypeId="2" ParentId="10643" CreationDate="2017-08-03T16:13:09.993" Score="1" Body="&lt;p&gt;Streams that are shallow relative to the thickness of the aquifer in which they lie. Such streams often are referred to in the literature as partially penetrating streams. Most streams are partially penetrating streams. Seepage between a partially penetrating stream and the contiguous aquifer occurs both horizontally and vertically through streambank and streambed materials.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/32k3G.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/32k3G.png&quot; alt=&quot;A shallow stream partially penetrating aquifer&quot;&gt;&lt;/a&gt;&#xA;Image Source:USGS&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are a few streams that are deep enough to penetrate the full thickness of the aquifer in which they lie. Such streams often are referred to fully penetrating streams. Seepage between a fully penetrating stream and the contiguous aquifer occurs horizontally through streambank materials.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/zuzyA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zuzyA.png&quot; alt=&quot;A deep stream fully penetrating aquifer&quot;&gt;&lt;/a&gt;&#xA;Image Source:USGS&lt;/p&gt;&#xA;" OwnerUserId="9553" LastEditorUserId="9553" LastEditDate="2017-08-04T10:15:06.630" LastActivityDate="2017-08-04T10:15:06.630" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="11992" PostTypeId="2" ParentId="7436" CreationDate="2017-08-03T22:18:44.380" Score="3" Body="&lt;p&gt;Having worked on this problem myself in my master's thesis, see our paper in geophysical journal international(GJI) at &lt;a href=&quot;http://ceas.iisc.ernet.in/~bsreeni/gji14.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://ceas.iisc.ernet.in/~bsreeni/gji14.pdf&lt;/a&gt; the likely timeframe of this event is about 1000 years as per our calculations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For us humans this is definitely not instantaneous but for the timeframes relevant to earth's history, this is a very short amount of time. So, don't lose your sleep over it, it won't happen in your lifetime. &lt;/p&gt;&#xA;" OwnerUserId="10712" LastActivityDate="2017-08-03T22:18:44.380" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11993" PostTypeId="2" ParentId="8876" CreationDate="2017-08-03T22:26:47.947" Score="3" Body="&lt;p&gt;Although Temperature boundary conditions at the mantle do affect the dynamo that sustains itself in the earth's core, it is unlikely that the dynamo's genesis came out of polarized regions in the earth's mantle. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regardless of the manner of genesis of the core, it is now a self-sustaining dynamo where electric current creates a magnetic field which in turn generates electric current owing to rotation of the earth much as in an electric generator. If you want to read more about it in detail, I would recommend an excellent review paper by Prof. Binod Sreenivasan available at &lt;a href=&quot;http://ceas.iisc.ernet.in/~bsreeni/currsci10.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://ceas.iisc.ernet.in/~bsreeni/currsci10.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="10712" LastActivityDate="2017-08-03T22:26:47.947" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11994" PostTypeId="2" ParentId="9907" CreationDate="2017-08-03T22:34:49.093" Score="4" Body="&lt;p&gt;As per our numerical calculations it takes about ~1000 years to completely flip the dynamo, that being said the current models are not even close to the actual parameters in the earth's core because it would take a humongous time to compute way beyond the capability of current computers. We published a paper back in 2014 where we talk about the role of buoyancy in polarity reversals,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://ceas.iisc.ernet.in/~bsreeni/gji14.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://ceas.iisc.ernet.in/~bsreeni/gji14.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The critical parameter that supports a stable dipole is helicity. Strong buoyancy offsets helicity in the outer core thus depriving it of a stable dipolar magnetic field. If you want to understand more about the terms I am talking about, here is a link to an excellent review/introductory paper&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://ceas.iisc.ernet.in/~bsreeni/currsci10.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://ceas.iisc.ernet.in/~bsreeni/currsci10.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="10712" LastActivityDate="2017-08-03T22:34:49.093" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11995" PostTypeId="2" ParentId="8877" CreationDate="2017-08-03T22:56:23.103" Score="1" Body="&lt;p&gt;The swirls that you are talking about probably refer to convection columns in the earth, but I have never read the word &quot;swirl&quot; in the literature for those. An introductory paper for you might be this : &lt;a href=&quot;http://ceas.iisc.ernet.in/~bsreeni/currsci10.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://ceas.iisc.ernet.in/~bsreeni/currsci10.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can have a look at the references of this paper if this doesn't satisfy you. Also, these convection columns give rise to the stable dipole of this earth and will remain stable until a reversal happens inside the core. They are a result of complex intermingling of different types of forces inside the core namely the coriolis and the buoyancy forces.&lt;/p&gt;&#xA;" OwnerUserId="10712" LastActivityDate="2017-08-03T22:56:23.103" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11997" PostTypeId="2" ParentId="11978" CreationDate="2017-08-04T11:20:45.923" Score="1" Body="&lt;p&gt;As already commented; a good indicator for rain in soundings is that the lower troposphere is saturated by water. Individual saturated levels would imply moisture, but if the moisture doesn't reach the surface then it maybe just clouds or rain that evaporates before reaching surface (virga). The deeper the saturated layer, the better indicator for rain it is. The dew point and ambient temperature doesn't necessarily have to be exactly the same, but very close to each others.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You pointed out cin and cape, but they are really just indicators for forcing convection and aren't necessarily present when it already rains.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastActivityDate="2017-08-04T11:20:45.923" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="11999" PostTypeId="1" CreationDate="2017-08-04T17:36:30.000" Score="0" ViewCount="104" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/5PmGL.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pbZ1u.jpg&quot; alt=&quot;enter image description here&quot;&gt; &#xA;This Crystal has a couple gas bubbles and impurities in the very center of it it breaks only one way it is 4720 carats very beautiful very hard&lt;/p&gt;&#xA;" OwnerUserId="8459" LastActivityDate="2017-08-06T01:05:35.657" Title="What are these rocks" Tags="|mineralogy|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12000" PostTypeId="2" ParentId="11963" CreationDate="2017-08-04T20:25:51.427" Score="1" Body="&lt;p&gt;I would:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Compute (U,V) transport on the model's C grid. This is easy if the model returns a batotropic velocity.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Define a set of points S along the transect. The points should have spacing comparable to the model's horizontal resolution.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Interpolate (U,V) transport to S. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Find the component of (U,V) perpendicular to your transect.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Iterate over model outputs. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I can't say much about general numerical processing toolboxes. It looks like there are several for ROMS and MATLAB; google &quot;ROMS toolbox arango&quot; (it has been a long time since I used ROMS).&lt;/p&gt;&#xA;" OwnerUserId="8468" LastActivityDate="2017-08-04T20:25:51.427" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12003" PostTypeId="1" CreationDate="2017-08-04T22:23:41.747" Score="2" ViewCount="155" Body="&lt;p&gt;I have a lot of free time and often observe and take photos of the sky. Along with that, I always try to figure out what exactly I saw. I think that I have the basic understanding of clouds and cloud classification, but sometimes I see a situation which doesn´t fit the articles about clouds and there is a problem in classification. I have the biggest problem in case of the strange altocumulus lenticularis - pileus / velum clouds. See the photos below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KGFDY.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KGFDY.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;The first photo - several pileus clouds forming &#xA;&lt;a href=&quot;https://i.stack.imgur.com/UH2Dv.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UH2Dv.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;Second photo - I would say this is not a pileus. The two photos were taken in the same day, few minutes difference.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/NUToF.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NUToF.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;The thirs photo - there is a lenticular cloud on the left. On the right there is.. I dont know. I would not say it is a pileus cloud.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to definitions, there is no strict difference between pileus and velum. I am fine with it. I have seen some pileus clouds and those are often very thin, sometimes multi-layered. Velum is, in fact, a large (horizontaly expanded) pileus. I am fine with it. But, according to some definitions, it would be classified as altocumulus / altostratus, if there were no connections to the cumulus top. That makes me confused. I have seen many &quot;pileus&quot; clouds that were not tha classic, pileus. Those looked like altocumulus lenticularis AND isolated Ac len were present on the sky in these situations. Definition of altocumulus lenticularis doesn´t say anything about connection with low level clouds, though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A situation I came across many times.. the sky is full of isolated cumulus mediocris clouds &amp;amp; altocumulus lenticularis clouds. Ac len are supposed to form above terrain elevations, but I believe that there is a mechanism which allows them to grow above cumulus clouds. I have seen many photos all over the world showing a typical cumulus mediocris connected with a relatively large altocumulus. Like this one:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.flickr.com/photos/jsjgeology/27681312683/in/faves-130789578@N06/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.flickr.com/photos/jsjgeology/27681312683/in/faves-130789578@N06/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My intuition says that it should not be classified as a pileus or velum cloud.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Have you ever seen the same thing happening ? What do you think ?&lt;/p&gt;&#xA;" OwnerUserId="7031" LastActivityDate="2024-02-25T16:02:21.000" Title="Pileus / velum &amp; altocumulus / altostratus - classification problems" Tags="|meteorology|atmosphere|clouds|troposphere|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12004" PostTypeId="2" ParentId="11999" CreationDate="2017-08-05T04:22:12.153" Score="4" Body="&lt;p&gt;looks like a broken block of glass from a glass factory, called glass slag or chunk glass, you can get a whole range of hardness and color depending on what type of glass they were making. People often use it to make art.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nWYea.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nWYea.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-08-05T04:22:12.153" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12005" PostTypeId="1" AcceptedAnswerId="12006" CreationDate="2017-08-05T13:52:28.003" Score="4" ViewCount="970" Body="&lt;p&gt;From the BBC's &lt;a href=&quot;http://www.bbc.com/news/world-europe-40836301&quot; rel=&quot;nofollow noreferrer&quot;&gt;Russia: Eight missing in flooded diamond mine&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BuTCv.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BuTCv.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2017-08-05T15:23:38.003" Title="Why do diamond mines seem to always appear conical? Are the above-ground mines all that way? All at about the same angle?" Tags="|mining|diamond|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12006" PostTypeId="2" ParentId="12005" CreationDate="2017-08-05T15:23:38.003" Score="7" Body="&lt;p&gt;The main hard rock sources of diamonds are either &lt;a href=&quot;https://en.wikipedia.org/wiki/Kimberlite&quot; rel=&quot;noreferrer&quot;&gt;kimberlites&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Lamproites&quot; rel=&quot;noreferrer&quot;&gt;lamproites&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many kimberlite and lamproite deposits occur as:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;carrot-shaped, vertical intrusions termed 'pipes'&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As the term &quot;carrot-shaped&quot; suggests, the general shape of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Volcanic_pipe&quot; rel=&quot;noreferrer&quot;&gt;pipes&lt;/a&gt; is conical and when viewed in horizontal cross-sections they are generally quasi-circular.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/w3Ld2.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/w3Ld2.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When such structures are mined by open cut methods, as with open cut mines of &lt;a href=&quot;http://www.thefreedictionary.com/tabular&quot; rel=&quot;noreferrer&quot;&gt;tabular&lt;/a&gt; orebodies it is impossible to mine any open pit to any great depth with vertical walls for ground stability reasons. The mine walls are stepped and the parts of the walls between the horizontal steps are sloped. Because of this, open pit mines start out wide at the top, on the surface, and they get narrower with depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the deposit being mined has a quasi-circular horizontal cross-section and is shaped something like a carrot then the open cut mine will also be conical or quasi-conical in shape.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-08-05T15:23:38.003" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12007" PostTypeId="2" ParentId="11999" CreationDate="2017-08-06T01:05:35.657" Score="0" Body="&lt;p&gt;Definitely looks like broken, human-made glass. The presence of bubbles pretty much clinches it.&lt;/p&gt;&#xA;" OwnerUserId="10721" LastActivityDate="2017-08-06T01:05:35.657" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12011" PostTypeId="1" AcceptedAnswerId="12012" CreationDate="2017-08-06T14:12:34.610" Score="11" ViewCount="4614" Body="&lt;p&gt;How could this pyramidal peak have been formed in Antarctica? Little is known about it as far as I know but what is known is that its miles away from any existing plate boundary and its shape is also highly atypical, hence I present the above question. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question bases on two sub-questions really:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A) How did it form so far away from a plate boundary?&#xA;B) How did it form in this unusual shape?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hbPZH.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hbPZH.jpg&quot; alt=&quot;Aptly named,&amp;#39;The Pyramid&amp;#39;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/The_Pyramid_(Antarctica)&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/The_Pyramid_(Antarctica)&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="10723" LastEditorUserId="2470" LastEditDate="2021-07-06T06:58:42.137" LastActivityDate="2021-07-06T06:58:42.137" Title="How could this pyramidal Mountain have been formed?" Tags="|geology|plate-tectonics|glaciology|mountains|antarctica|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12012" PostTypeId="2" ParentId="12011" CreationDate="2017-08-06T17:43:17.077" Score="15" Body="&lt;p&gt;Such forms tend to be created by glacial activity, which, ahem, the ice-covered continent is known for. Much discussion of this in the related question in Skeptics: &lt;a href=&quot;https://skeptics.stackexchange.com/questions/18955/are-there-three-pyramids-in-antarctica&quot;&gt;Are there three pyramids in Antarctica?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's &lt;a href=&quot;https://en.wikipedia.org/wiki/Pyramidal_peak&quot; rel=&quot;noreferrer&quot;&gt;the generic answer in Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A pyramidal peak, sometimes in its most extreme form called a glacial&#xA;  horn, is an angular, sharply pointed mountain peak which results from&#xA;  the cirque erosion due to multiple glaciers diverging from a central&#xA;  point. It may be an example of a nunatak.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Here's &lt;a href=&quot;http://www.acegeography.com/landforms-of-glacial-erosion.html&quot; rel=&quot;noreferrer&quot;&gt;a diagram of the formation process posted on Ace Geography&lt;/a&gt;:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/TsBC0.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TsBC0.jpg&quot; alt=&quot;Formation of a glacial trough&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not knowing the specifics of the featured peak, as I understand it there are two general mechanisms of glacial erosion that apply:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Assume we begin with some sort of mounded terrain, or a relatively small protrusion on a larger continental surface like Antarctica. In a very cold environment, precipitation will fall as snow, mound up, and turn into ice. Generally, more ice will form on whatever side of the mound that is sheltered from sunlight (north slopes in the northern hemisphere, south slopes in the southern. Eventually the ice will move under its own weight, abrading the surface as it goes in a manner that will tend to exaggerate the original geometry of the mound. If the mound starts with or develops a slight dip in the slope, ice flowing off the back and side walls will dig a cirque or bowl. Depending on the starting conditions, your mound may develop several cirques; as ice grinds away at the lower elevations, you may wind up with a central, relatively slender peak with several ridges and valleys.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;A second mechanism is having a glacier coming down a broader slope and cutting through an existing ridge. (Your ridgeline may begin with a triangular cross-section, or may have developed one from the glacial processes mentioned above.) At some point, ice from a higher elevation will flow across or through your ridgeline (just as a river would), eroding a gorge through the ridge. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Inevitably, given enough material to work from, and even with a relatively smooth starting surface, the erosive power of ice will give you steep slopes and some pyramidal structures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dGBgK.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dGBgK.gif&quot; alt=&quot;Pyramidal peak graphic from BBC&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7314" LastEditorUserId="7314" LastEditDate="2017-08-06T20:44:42.053" LastActivityDate="2017-08-06T20:44:42.053" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12013" PostTypeId="1" CreationDate="2017-08-06T18:15:22.233" Score="2" ViewCount="3267" Body="&lt;p&gt;Saprolite and Regolith both imply loose material, is one a subset of the other how can I differentiate them ?&lt;/p&gt;&#xA;" OwnerUserId="7954" LastActivityDate="2019-06-04T06:37:41.320" Title="What is the difference between Saprolite and Regolith?" Tags="|sedimentology|soil|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12015" PostTypeId="2" ParentId="12013" CreationDate="2017-08-06T19:41:28.873" Score="2" Body="&lt;p&gt;In short, saprolite does make up the regolith. Saprolite is a term for in place, weathered rock. Regolith encompasses all the heterogeneous components of loose material covering the solid rock of the earth or other planetary bodies.&lt;/p&gt;&#xA;" OwnerUserId="10684" LastActivityDate="2017-08-06T19:41:28.873" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12017" PostTypeId="1" CreationDate="2017-08-06T21:29:09.837" Score="4" ViewCount="43" Body="&lt;p&gt;TL;DR: How susceptible is winter wheat to wildfire, in the environment that winter wheat is used? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The scenario:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shallow water table, a steppe environment, deep-root winter wheat and a HIGH occurrence of lightning strikes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would wildfires be a realistic risk? Wouldn't the wheat be too hydrated to be set alight?&lt;/p&gt;&#xA;" OwnerUserId="10727" LastActivityDate="2017-08-06T21:29:09.837" Title="Winter Wheat &amp; Wildfires" Tags="|lightning|agriculture|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12018" PostTypeId="2" ParentId="11954" CreationDate="2017-08-07T01:31:05.620" Score="0" Body="&lt;p&gt;A planet has been theorized that forms in a primordial disk of high carbon content. See &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_planet&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Carbon_planet&lt;/a&gt;. This planet's crust would have a high hydrocarbon content and thus not be very &quot;solid&quot;. However, such a planet might theoretically have volcanoes that erupt diamonds, so an alien could build there home out of diamond!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another hypothetical planet is a waterworld or ocean planet. If there is indigenous life then the only &quot;above water surface&quot; would be composed of life (ie: mats of algae type material floating on the sea).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as mountains go, this is not a question of solid or not solid. A large superearth would likely not have much in the way of mountains because of the high gravity at the surface. It might be noted that with out plate tectonics, we wouldn't have mountains and the Earth could arguably be covered in a global ocean.&lt;/p&gt;&#xA;" OwnerUserId="4600" LastActivityDate="2017-08-07T01:31:05.620" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12019" PostTypeId="1" CreationDate="2017-08-07T02:12:14.670" Score="1" ViewCount="37" Body="&lt;p&gt;I have an accelerometer on a table that gives me the $x$, $y$, and $z$ axis acceleration in $m/s^2$ when I move the table. Is there a formula or method to pass this data to a earthquake grade in a Richter Rank?&lt;/p&gt;&#xA;" OwnerUserId="10729" LastActivityDate="2017-08-07T20:55:36.687" Title="Is it possible to obtain the richter grade of an earthquake with the data of an accelerometer?" Tags="|measurements|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12021" PostTypeId="1" CreationDate="2017-08-07T03:36:24.053" Score="3" ViewCount="52" Body="&lt;p&gt;The OLR (outgoing longwave radiation) from the top of the atmosphere to space is composed of radiative energy emitted by the atmosphere at all altitudes, as well as the surface. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;How is the radiative power of the OLR leaving the top of the atmosphere distributed with the altitude the OLR originated from?&lt;/li&gt;&#xA;&lt;li&gt;How is that distribution changing over time? &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="10728" LastActivityDate="2017-08-07T03:36:24.053" Title="How is OLR power of the atmosphere distributed with altitude?" Tags="|climate-change|climate-models|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12022" PostTypeId="1" CreationDate="2017-08-07T10:35:11.127" Score="4" ViewCount="30" Body="&lt;p&gt;The rift zones around the Ethiopian Plateau, Mid Ethiopian Rift, are stil tectonically active since Somalia is separating from Nubia at a rate of 6–7 mm annually&lt;sup&gt;[1]&lt;/sup&gt;, and Arabia is rotating counter-clockwise relative Nubia, with continued spreading of the Red Sea Rift and Gulf of Aden rift.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Have there been any measurements on wether the Ethiopian Plateau uplift, which resulted from the tectonic forces in the region over the past 30 million years or so, is still ongoing?&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;References&lt;/h1&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Fernandes, Ambrosius, et al (2004). Angular velocities of Nubia and Somalia from continuous GPS data: implications on present-day relative kinematics. Earth Planet. Sci. Lett. 222: 197–208.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="10733" LastActivityDate="2017-08-07T10:35:11.127" Title="Is the Ethiopian Plateau uplift still ongoing?" Tags="|geology|tectonics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12023" PostTypeId="2" ParentId="11930" CreationDate="2017-08-07T18:12:00.723" Score="3" Body="&lt;p&gt;Coal and other organics like wood and straw decompose when exposed to oxygen, that decomposition is an exothermic oxidation reaction so it heats the material around it which accelerates the decomposition. This can be reasonably harmless if there's enough airflow to cool the pile and carry away the small volumes of flammable volatile gases formed by what is essentially decaying plant matter. The presence of water makes the process more dangerous in two ways, it fills pore spaces that would otherwise provide air cooling to the pile as a whole &lt;em&gt;and&lt;/em&gt; it provides more hydrogen to the decomposition chemistry while excluding some oxygen which creates more volatile compounds with increasingly low ignition points.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2017-08-07T18:12:00.723" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12024" PostTypeId="2" ParentId="12019" CreationDate="2017-08-07T20:55:36.687" Score="3" Body="&lt;p&gt;The Richter Number is a measure of total energy released in an earthquake.  To calculate it, even roughly, you need to know the epicenter of the earthquake (that needs at least three measurements from three locations) and the length and intensity of the shaking to determine the energy contained in the waveform.  All you seem to have with your accelerometer is the peak intensity of the shaking at a single point.  So the answer is no.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2017-08-07T20:55:36.687" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12027" PostTypeId="2" ParentId="11920" CreationDate="2017-08-08T04:55:29.167" Score="6" Body="&lt;p&gt;I agree with commentator @John, this is a fossil coral.  The coral animal (the polyp) builds a column, and as it ages it closes off the bottom and extends the upper lip.  In some of the views you see the column structure.  In others you see the arrangement of polyps.  It looks like the cells of the coral are filled in with calcite, which probably made the fossil harder than the surrounding rock.  When the rock weathered the fossil coral broke apart.  It looks like this piece is a rounded pebble from a stream bed.  Or possibly the coral broke up and was rounded by wave action.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Compare this picture &lt;a href=&quot;http://www.fossilmuseum.net/fossil-art/cnidaria/tabulatecorals.jpg&quot; rel=&quot;noreferrer&quot;&gt;http://www.fossilmuseum.net/fossil-art/cnidaria/tabulatecorals.jpg&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2017-08-08T04:55:29.167" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12028" PostTypeId="1" CreationDate="2017-08-08T07:25:30.327" Score="3" ViewCount="1167" Body="&lt;p&gt;How is Doppler radar used in rain prediction?&lt;/p&gt;&#xA;" OwnerUserId="10738" LastEditorUserId="6465" LastEditDate="2017-09-04T08:00:30.343" LastActivityDate="2019-07-08T22:28:44.217" Title="How is Doppler radar used in rain prediction?" Tags="|rainfall|rain|" AnswerCount="5" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12030" PostTypeId="1" AcceptedAnswerId="12033" CreationDate="2017-08-08T09:38:19.707" Score="5" ViewCount="676" Body="&lt;p&gt;In the open sea the speed of the current in the developed sea can be estimated as 3% the wind velocity at 10 meters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/3060/why-is-ocean-surface-velocity-around-3-of-wind-velocity&quot;&gt;Why is ocean surface velocity around 3% of wind velocity?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a similar estimation for the depth of such a current?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Intuitively, a surface current can't continue to move towards the shoreline, as there is not enough space underneath for a bottom current to compensate the surface current, and those currents would interfere. Also, there should be some mixing of the water layer in the breaking waves near the shore, that would contribute to canceling the surface current too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Having a wind-induced surface current directed towards the shoreline, how close to the shore can such current continue, depending on the steepness of the seabed, the wind and the wave conditions?&lt;/p&gt;&#xA;" OwnerUserId="10739" LastEditorUserId="111" LastEditDate="2017-08-11T11:45:45.100" LastActivityDate="2017-08-11T11:45:45.100" Title="Depth of the wind-induced currents and the shoreline" Tags="|ocean|oceanography|wind|waves|ocean-currents|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12031" PostTypeId="1" AcceptedAnswerId="12038" CreationDate="2017-08-08T11:41:58.770" Score="3" ViewCount="4235" Body="&lt;p&gt;I computed the daily reference evapotranspiration $ET_0$ using the &lt;a href=&quot;http://www.fao.org/docrep/X0490E/x0490e00.htm#Contents&quot; rel=&quot;nofollow noreferrer&quot;&gt;Crop evapotranspiration - Guidelines for computing crop water requirements - FAO Irrigation and drainage paper 56&lt;/a&gt;. The outputs seems realistic regarding the dynamic and the annual total but the time series contains negative values (about 1% of the time series).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The computation involves many equations for the sub-terms but the general formula is the following:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;ET_0 = \frac{0.408 \Delta (R_n - G) + \gamma \frac{900}{T + 273}U_2(e_s - e_a)}{\Delta + \gamma(1+0.34 U_2)}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;with&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$ET_0$ reference evapotranspiration [mm day-1],&lt;/li&gt;&#xA;&lt;li&gt;$R_n$ net radiation at the crop surface [MJ m-2 day-1],&lt;/li&gt;&#xA;&lt;li&gt;$G$ soil heat flux density [MJ m-2 day-1] (=0 in this case),&lt;/li&gt;&#xA;&lt;li&gt;$T$ mean daily air temperature at 2 m height [°C],&lt;/li&gt;&#xA;&lt;li&gt;$U_2$ wind speed at 2 m height [m s-1],&lt;/li&gt;&#xA;&lt;li&gt;$e_s$ saturation vapour pressure [kPa],&lt;/li&gt;&#xA;&lt;li&gt;$e_a$ actual vapour pressure [kPa],&lt;/li&gt;&#xA;&lt;li&gt;$e_s - e_a$ saturation vapour pressure deficit [kPa],&lt;/li&gt;&#xA;&lt;li&gt;$\Delta$ slope vapour pressure curve [kPa °C-1],&lt;/li&gt;&#xA;&lt;li&gt;$\gamma$ psychrometric constant [kPa °C-1].&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;It appears that the negative values are due to a negative values of the net radiation $R_n$. A negative value of $R_n$ makes sense but what about negative $ET_0$ ? How should I deal with these as I intend to use $ET_0$ as input for hydrological modelling ?&lt;/p&gt;&#xA;" OwnerUserId="3363" LastActivityDate="2017-12-03T17:19:52.663" Title="Does negative reference evapotranspiration make sense using FAO Penman-Monteith equation?" Tags="|meteorology|hydrology|evaporation|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12033" PostTypeId="2" ParentId="12030" CreationDate="2017-08-08T14:43:59.953" Score="4" Body="&lt;p&gt;First, a bit of background, following the Navier-Stokes equations and assuming steady state conditions, we can obtain a simplified balance known as Ekman balance for the boundary layer of the upper ocean (order hundred meters). In this part of the ocean horizontal gradients are small compared to vertical gradients. Under these conditions, there is a balance between Coriolis, and friction (sometimes the pressure gradient force needs to also be considered in the balance). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The resulting theoretical flow has a vertical structure with decreasing magnitude with depth and flow direction progressively rotating to the right (left in the southern hemisphere) as depth is increasing. This is known as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ekman_layer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ekman spiral&lt;/a&gt;. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/w5qGS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/w5qGS.jpg&quot; alt=&quot;Ekman spiral&quot;&gt;&lt;/a&gt; Source: &lt;a href=&quot;http://offshoreengineering.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://offshoreengineering.com&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Under these conditions, in the open ocean (in fact assuming an infinitely deep ocean), the transport in the Ekman layer is perpendicular to the wind direction. The depth of the Ekman layer, or Ekman depth, is simply dependent on Coriolis and viscosity: $$D_e = \sqrt{2K_m\over f}$$ where $K_m$ is the kinematic turbulent viscosity (assumed constant) and $f$ is the Coriolis parameter (a typical value for mid-latitudes is $10^{-4}$ $s^{-1}$). Typical Ekman depths are of order 10 to 30 meters. Typical values for $K_m$ are around $0.1$ $m^2/s$ (not to be confused with molecular viscosity that is around $10^{-6}$ $m^2/s$) but can vary by several orders of magnitude, resulting in a range of $D_e$ of $10-150m$. A good explanation of Ekman balance and much more information can be found in &lt;a href=&quot;http://ta.twi.tudelft.nl/dv/users/schuttel/gfd2.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cushman-Roisin &amp;amp; Beckers&lt;/a&gt; (&lt;a href=&quot;http://thayer.dartmouth.edu/~d30345d/books/EFM/GFDchap8.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chapter 8&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While all that is useful in a theoretical setting, the depths obtained from observations of the Ekman depth can be approximated by the expression: $$D_e = 0.4\sqrt{\tau\over f^2 \rho_0 }$$ where $\tau$ is the wind stress magnitude and $\rho_0$ is water density. The factor $0.4$ has been derived empirically and can varied slightly under different oceanic conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All that was describing the surface boundary layer, but in reality a bottom boundary layer also forms. The solution to the bottom layer can also be approximated as an Ekman layer for which the forcing is not the wind, but the bottom friction. The resulting boundary layer also has an Ekman depth approximated with the expression above. In an sloping bottom, the boundary layer follows the bottom slope and the thickness (depth above bottom) of the layer (measured perpendicular to the bottom) is scaled by the cosine of the bottom slope.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Taking 10 meters (one of the smallest values in mid-latitudes) for the surface and bottom boundary layer thicknesses, that implies that in water depths shallower than 20 m the two boundary layers overlap. In water depths shallower than that, the transport in the surface layer is no longer perpendicular to the wind direction. The momentum input into the water by the wind (wind stress) is affected by the presence of the bottom and it is directly dissipated by bottom friction. The mixing by the wind (and wave breaking near the surf zone) results in additional mixing through the water column and facilitating well-mixed water columns. Under these conditions the wind-induced currents extend all the way to the bottom with the direction of the flow being a function of bottom depth, wind direction, and bottom slope. The presence of wind-induced currents does not preclude the occurrence of flow in the opposite direction of the wind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A fantastic article summarizing the different flow conditions under different wind and wave fields in shallow water depths is given in &lt;a href=&quot;http://dx.doi.org/10.1146/annurev-marine-120709-142745&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lentz and Fewings (2012).&lt;/a&gt; &lt;a href=&quot;http://www.ccpo.odu.edu/~klinck/Reprints/PDF/lentzAnnRevMS12.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Reprint)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additional factors to consider are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;stratification by temperature and salinity that reduces mixing and helps maintain a separation between surface and bottom layers (some effects described &lt;a href=&quot;http://rachelhorwitz.weebly.com/inner-shelf.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;).&lt;/li&gt;&#xA;&lt;li&gt;what happens when the wind is changing speed and direction (non-steady state)?&lt;/li&gt;&#xA;&lt;li&gt;what happens at the Equator where the Coriolis parameter is zero?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="111" LastActivityDate="2017-08-08T14:43:59.953" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12034" PostTypeId="2" ParentId="12028" CreationDate="2017-08-08T22:50:19.813" Score="0" Body="&lt;p&gt;First rain -oversimplified.  Rain occurs when water vapor in the air cools such that the air becomes saturated and the water vapor condenses as liquid water.  It’s colder up high such that hot, vapor laden air raises, cools and releases rain.  Lots of air and water moving about.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Doppler is the change in frequency of a wave as it bounces off a moving target.  Radar is a wave that bounces off an object and detected back at the source.  When radar bounce off water laden air moving upward (detected by the Doppler Effect) and cooling, it’s an indication that something rain like is occurring. Differing movements are indicative of differing parts of a storm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not long ago one or two planes full of people would crash at airport when microbursts of cool air would descend vertically and drive them into the ground.  Since Doppler radar we can see these coming and avoid them.&lt;/p&gt;&#xA;" OwnerUserId="9548" LastActivityDate="2017-08-08T22:50:19.813" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12037" PostTypeId="1" CreationDate="2017-08-09T02:29:59.927" Score="1" ViewCount="85" Body="&lt;p&gt;Look up Clearwater Florida on Wikipedia and it gives you the average low for the Months of July and August as being 74.2F. About 3-4 years ago I picked up running as a main hobby and the temperature is the biggest factor determining my speed every day. Since then Ive been following the temperature and I am sure that for the last 2-3 years at least the daily low has been 78F to 82F for a mean of about 80F.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is the recent average lows for July and August so much warmer than the historical average?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this just a recent trend due to El Nino or some other weather pattern?&lt;/p&gt;&#xA;" OwnerUserId="10743" LastActivityDate="2017-08-09T14:22:27.343" Title="Why has the average low for the hottest months in Clearwater Florida about 5 degrees higher than the historical average?" Tags="|meteorology|climate-change|climate|temperature|climate-models|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12038" PostTypeId="2" ParentId="12031" CreationDate="2017-08-09T04:11:15.643" Score="5" Body="&lt;p&gt;Short answer, especially if it is about 1% of the time series and these values are just slightly negative, this likely indicates that the ET needs to be recalibrated slightly, and for practical purposes you can set the ET on those days to 0 mm/d. The ET calculations typically calculate potential ET, meaning that if there is no water available no ET will occur, and a similar concept applies to negative ET values (i.e. no demand for water -&gt; no ET).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A couple of notes &lt;br &gt;&#xA;- the reference $ET_0$ calculations were meant for ten-day or monthly time steps, not daily, which may be a reason for these results (see &lt;a href=&quot;http://www.fao.org/docrep/X0490E/x0490e06.htm#need%20for%20a%20standard%20eto%20method&quot; rel=&quot;noreferrer&quot;&gt;top of Ch 2&lt;/a&gt;) &lt;br &gt;&#xA;- the equation seems to be for a specific type of reference grass, and they suggest adjusting the $ET_0$ based on crop type using a ratio; another potential adjustment to make&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Overall if the negative values are infrequent and close to zero then likely setting to zero is not an issue, if the values are much less than zero than check the calculations and try the suggestions above to recalibrate the calculation.&lt;/p&gt;&#xA;" OwnerUserId="8440" LastActivityDate="2017-08-09T04:11:15.643" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12039" PostTypeId="2" ParentId="11973" CreationDate="2017-08-09T06:55:42.983" Score="3" Body="&lt;p&gt;At the coast the horizon facing the ocean is unobstructed, so a larger part of the sky is visible than inland, where trees, buildings, etc., block the view of the horizon. Also, the horizon sky is brighter than the overhead sky. At or near the horizon the sky appears lighter blue than at the zenith, or even whitish. Looking vertically at the zenith is looking through one air mass; looking horizontally at the horizon is looking through 40 air masses. Although the atmosphere scatters short wavelengths at the violet end of the spectrum most effectively, 40 air masses scatters enough of even the longer red wavelengths that the horizon sky appears very light blue or even whitish. 40 air masses is enough to scatter all of the light. Greater scattering of light causes the near-horizon sky to be brighter. (Even the zenith sky appears blue rather than violet because the Sun emits more blue light than violet and the eye is more sensitive to blue light than violet.) &lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-08-09T06:55:42.983" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12040" PostTypeId="1" CreationDate="2017-08-09T11:53:23.267" Score="0" ViewCount="48" Body="&lt;p&gt;Can anyone tell me what are the minerals that can found at home or something that can be seen in yard or in waste/trash bins. &lt;/p&gt;&#xA;" OwnerUserId="10744" LastActivityDate="2017-08-09T12:23:41.380" Title="What are the usable minerals that can be found in our daily life?" Tags="|mineralogy|" AnswerCount="1" CommentCount="1" ClosedDate="2017-08-09T18:27:38.760" ContentLicense="CC BY-SA 3.0" />
  <row Id="12041" PostTypeId="2" ParentId="12040" CreationDate="2017-08-09T12:23:41.380" Score="2" Body="&lt;p&gt;This question is somewhat vague &amp;amp; broad. It almost looks like a homework question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For starters, in the kitchen there's salt, NaCl.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the bathroom, talcum powder, which is ground up talc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the garden shed there's fertilizers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the yard, soil contains a numerous minerals, which will differ from location to location because of different types of soil. Locations with sandy soils will contain silica.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-08-09T12:23:41.380" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12042" PostTypeId="2" ParentId="12037" CreationDate="2017-08-09T14:22:27.343" Score="2" Body="&lt;p&gt;What you are observing is called anecdotal weather observations.  I will address it in a number of points, none of which many people will agree with, but so be it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2-3 years is weather, not climate.  Climate is measured in millennia, not days.  Historical averages are measured, well historically, which for most locations in the US is 50-300 years.  During those years, methods of measurement have changed, so historical numbers may also have glitches in them, such as the the highest US temperature ever recorded is still in dispute because of how it was measured.  But historical averages are calculated from all of those years, ones with droughts, unseasonable cold fronts, and so on.  Warming patterns which are the basis for global warming studies are based on looking at all this data, plus many years of indirect data from ice cores, tree rings, sediment deposits, and many other sources, not from 2 years of personal study.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is routine to have years that are outside of the average, that is what averages are.  It is also human nature to amplify the variation and see extremes.  I did not go that far back, and I used only one source, but I looked at a little recent recorded data for Clearwater.  I took daily numbers and went with variations to the daily average temp for that date.  For Aug 2017, there are 8 days available thus, and the daily lows have been recorded as +17 degrees to average, or +2.15 degrees.  For 2016 back to 2013 you get +27, -2, +24 and +7 for Aug, or as an average daily difference about +0.87, -0.06, +0.77 and +0.23 with a average for the 4+ years of +0.38 to average.  Only the partial month for 2017 exceeds 1 degree variance to average.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;July numbers are, starting with 2017, 41, 37, -29, 13, -31 or in daily variations +1.32, +1.19, -0.94, +0.42, -1.00 for a 5 year average of +0.20.  Although the last two July's have exceeded the plus one degree variance, two of the prior three were almost the opposite.  That is weather and normal variation.  To get to climate numbers requires looking at those patterns over centuries, not over a couple years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Trust me, I am not refuting global warming.  I am however refuting using such anecdotal observations as a bases for the claims.  Weather patterns work in cycles, and before climate change claims can be made the cycles must be accounted for.  When a location has an especially hot day, or month and references are made to global warming, it make that side of the argument look silly.  When a blizzard occurs, there is a record low, or an seemingly especially cold day, and the deniers point and chant global warming and laugh, they may also feel they scored points, but under statistical analysis they look silly as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do not claim the above to be a statistical analysis.  I also did not cherry pick data, I simply only had time or willingness to do a quick 5 years.  That was more than enough to see yearly variations and demonstrate that a perceived variation of 4-5 degrees is actually 1, and 1 degree is still within typical yearly variation.  To make a real claim requires a pattern of trending real variation in a continuing upward direction and that require rigorous and systematic data collection and analysis.&lt;/p&gt;&#xA;" OwnerUserId="6178" LastActivityDate="2017-08-09T14:22:27.343" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12043" PostTypeId="2" ParentId="12028" CreationDate="2017-08-09T14:37:53.283" Score="-1" Body="&lt;p&gt;Doppler radar is not used any differently to predict weather than older forms of radar were, satellite imagery is, or how physical observations that were then called or telegraphed ahead of an advancing system.  The radar detects the presence of clouds with a water load that are likely to produce precipitation, or may already be doing so.  That is compared to the direction the potential precipitation is moving and historical records of when similar conditions have occurred in the past, how likely is it to be repeated for a given location.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An observation is made, hey there is a cloud back forming there that seems to hold a lot of water.  It is moving in this direction at this speed and the barometric pressure is doing this with a temperature like that.  The last 10 times we had conditions that matched this, it rained 7 times, so, let's say there is a 70% chance it is going to rain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Doppler radar is, in general terms, a more sensitive form of making these observations than older radar was, which was more sensitive and actuate than having physical observers a few hundred miles away calling and saying, hey, it's raining here.  You will probably get rain in a few hours.&lt;/p&gt;&#xA;" OwnerUserId="6178" LastActivityDate="2017-08-09T14:37:53.283" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12044" PostTypeId="2" ParentId="9914" CreationDate="2017-08-09T14:54:49.837" Score="4" Body="&lt;p&gt;if you want pure python&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;code&gt;conda install cdms2 -c conda-forge&lt;/code&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;then in python:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;code&gt;lats = cdms2.createGaussianAxis(128)&lt;/code&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;you can also create a full lat/lon grid:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;code&gt;grid = cdms2.createGaussianGrid(128)&lt;/code&gt;&lt;/p&gt;&#xA;" OwnerUserId="10745" LastActivityDate="2017-08-09T14:54:49.837" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12045" PostTypeId="1" AcceptedAnswerId="12047" CreationDate="2017-08-05T06:32:49.313" Score="14" ViewCount="1776" Body="&lt;p&gt;I was hiking a very popular trail in Akamina-Kishnena Provincial Park, and noticed these strange lines in the rocks on top of the mountain: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QhRKB.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QhRKB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The lines were parallel to each other, and were on both sides of the trail covering quite a large area of the mountain face. My best guess is that run off from snow melt could cause this, but they look almost like they were raked. The picture was take at around 2,400m in elevation. What causes this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the ridge we were on: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jiUKR.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jiUKR.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The lines were on the southern face of the mountain.&lt;/p&gt;&#xA;" OwnerUserId="702" OwnerDisplayName="ShemSeger" LastEditorUserId="6465" LastEditDate="2017-08-10T07:19:27.300" LastActivityDate="2017-08-10T18:32:01.607" Title="What causes this striped rock formation?" Tags="|mountains|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="12046" PostTypeId="2" ParentId="12028" CreationDate="2017-08-09T22:45:03.777" Score="1" Body="&lt;p&gt;The easiest answer is that Safe Haven is a movie, and the writer made a factual error (which is not uncommon). I have not watched that movie, so I am unsure what type of situation they were dealing with. Doppler radars do not predict, but they observe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is possible, however, is extrapolation and the creation of inferences. For example, tornadoes are not directly predicted by Doppler Radar, but by making inferences from the data, a meteorologist may detect a tornado. In a similar sense, if the radar-derived 'storm total precipitation' has estimated an average 0.25 inches of rain from a squall line for the past 200 miles, one may extrapolate, or estimate, that the squall line will produce ~0.25 inches of rain. Could the squall line alter its path or intensity and drastically change the amount? Sure, but without additional information, including information not derived from a radar, that would be a difficult task.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit&lt;/strong&gt;: Ok, I think I have a better idea of what the question was and how it can be answered.&#xA;Doppler radar can measure wind speed relative to the radar site. So if can sense how fast a storm is approaching. &lt;strong&gt;Assuming&lt;/strong&gt; the storm does not change it's speed, and given it's history, you can infer when it will arrive at the radar site. For example, if a storm is 50 miles away, and it moves at 25 miles per hour it will arrive in $50\text{ mi}\div 25\frac{\text{mi}}{\text{hr}}=2\text{ hr}$, provided the storm does not change.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2017-08-09T22:58:17.430" LastActivityDate="2017-08-09T22:58:17.430" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12047" PostTypeId="2" ParentId="12045" CreationDate="2017-08-09T23:14:53.107" Score="9" Body="&lt;p&gt;&lt;strong&gt;Frost heaving of the striped variety&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As soil freezes it expands, this slowly pushes coarser material outwards, (since no ice forms in the stones just between them). This forms in bands of coarse and fine material like you see in your image.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The effect only becomes more exaggerated as the soil gets more and more sorted, since the finer material holds more water and thus expands more. This also means that even the smallest variation in particle size can get the process started. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A variety of patterns can form; sloped ground is especially prone to this sort of striped frost sorting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;B and C in this image are examples from &lt;a href=&quot;http://rsta.royalsocietypublishing.org/content/371/2004/20120357&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; paper. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/UmHzE.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UmHzE.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.journals.uchicago.edu/doi/10.1086/623637&quot; rel=&quot;nofollow noreferrer&quot;&gt;Additional source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="6467" LastEditDate="2017-08-10T18:32:01.607" LastActivityDate="2017-08-10T18:32:01.607" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12048" PostTypeId="1" CreationDate="2017-08-10T05:55:35.363" Score="5" ViewCount="385" Body="&lt;p&gt;In a recent work, I'm trying to figure out the pollution situation of my case area. Dealing with the online equipments, I have got the PM2.5 and PM10 concentration time series for a whole year. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I plot their diurnal variation divided by the season.   &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;PM2.5    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qdF0T.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qdF0T.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;PM10    &lt;/p&gt;&#xA;&#xA;&lt;h2&gt;&lt;a href=&quot;https://i.stack.imgur.com/duIBx.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/duIBx.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Although this is a simple data visualization, I think there are some valuable information in the figures.  I have found several points that may be interesting, but I can't explain them well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1) The diurnal variations of PM2.5 in different seasons are more similar comparing with PM10.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) The peak hour in winter for both species are late for 1 hour comparing with other seasons in the daytime.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(3)  The concentration levels of both species between daytime and nighttime for spring are more close than other seasons &lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS: Some background of the case area &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ol&gt;&#xA;  &lt;li&gt;It is located in northeastern China as a industrial city with lots of metal mining and operation factories.  &lt;/li&gt;&#xA;  &lt;li&gt;The coal combustion behavior is more usual in winter for the need of domestic heating.    &lt;/li&gt;&#xA;  &lt;li&gt;The city is influenced by the dust storms originated from Takla Makan Desert and Gobi Desert.  &lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="5214" LastEditDate="2017-08-10T06:32:48.523" LastActivityDate="2017-08-10T06:32:48.523" Title="How to explain the diurnal variation for different seasons" Tags="|meteorology|atmosphere|air-pollution|air-quality|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="12049" PostTypeId="2" ParentId="2498" CreationDate="2017-08-10T09:22:46.930" Score="9" Body="&lt;p&gt;A paper on this topic just appeared: &lt;a href=&quot;http://iopscience.iop.org/article/10.3847/1538-4357/aa7a03/meta&quot; rel=&quot;nofollow noreferrer&quot;&gt;Multiple Climate States of Habitable Exoplanets: The Role of Obliquity and Irradiance&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In case of 90° obliquity, summer and winter would appear together with day and night, respectively. This means, in summer one hemisphere completely faces the Sun with 24h daylight a day causing extreme hot summers. The temperatures in winter very much depend on the hemisphere. In the Southern Hemisphere, oceans are predominant compared to the continents, having a very low albedo makes it possible to store the heat in summer. Thus, the winters in the Southern Hemisphere are still warm. In contrary, the Northern Hemisphere becomes rather cold in winter due to the small heat storage in the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The equator region is the coldest region on the planet, since this region has the lowest incoming solar radiation (Fig. 1a,b). This could lead to sea ice building around the equator region and provides an alternative hypothesis to Snowball Earth (&lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0012825207001808?via%3Dihub&quot; rel=&quot;nofollow noreferrer&quot;&gt;Williams, 2008&lt;/a&gt;): The High Obliquity, Low-latitude Ice, STrong seasonality (HOLIST) hypothesis for pre-Ediacaran glaciation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The warm poles and the cold equator significantly change the dominating jets. The mechanism can be explained by the thermal wind equation:&#xA;$$&#xA;p \dfrac{\partial u_g}{\partial p} = \dfrac{R}{f} \dfrac{\partial T}{\partial y} ~~,&#xA;$$&#xA;where $p$ is the pressure, $u_g$ the geostrophic zonal wind, $R$ the specific gas constant for air, $f$ the Coriolis parameter, $T$ the temperature, and $y$ the meridional distance in meters. The thermal wind equation shows that the vertical change in zonal wind is proportional to the meridional temperature gradient. Thus, the sign change of the meridional temperature gradient causes a sign change of the zonal wind. This means that the dominating jets turn into easterlies due to the reverse meridional temperature gradient (Fig. 1c,d).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the climate also depends on the initial condition of the planet, i.e., multiple climate states are possible for the same parameters. In case of 90° obliquity either a so-called &quot;Uncapped Cryoplanet&quot; or an &quot;Aquaplanet&quot; state exists (for further details see &lt;a href=&quot;http://iopscience.iop.org/article/10.3847/1538-4357/aa7a03/meta&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kilic et al., 2017&lt;/a&gt;). An Uncapped Cryoplanet has large areas of sea-ice around the equator and a permanent open ocean at the higher latitudes. This climate type posses a previously unknown meridional atmospheric circulation which is neither a thermally direct nor indirect cell but rather a superposition of both cell types (Fig. 1e).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oJC3C.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oJC3C.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;strong&gt;Figure 1:&lt;/strong&gt; Uncapped Cryoplanet (left column) and the Aquaplanet (right column) for a planet with 90° obliquity in southern summer: (a), (b) zonal mean air temperature, (c), (d) mass stream function (colour, positive for clockwise overturning) and zonal-mean zonal wind (contour, positive for westerlies), and (e), (f) the poleward energy flux for the eddy and the mean contribution, the total energy flux, and the meridional heat flux in the ocean. Note: The figure shows an aquaplanet configuration, i.e., continents were neglected.&lt;/p&gt;&#xA;" OwnerUserId="10747" LastEditorUserId="10747" LastEditDate="2017-10-20T16:34:38.323" LastActivityDate="2017-10-20T16:34:38.323" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12050" PostTypeId="1" CreationDate="2017-08-10T09:55:42.750" Score="2" ViewCount="87" Body="&lt;p&gt;For the past few years people have been trying to solve the global water problem (especially in Africa), and what better way than being echo friendly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my question is, can you use the tidal energy of the ocean to pump water via a ramp pump (works with a bunch of non-return valves and the fall of gravity).&#xA;In other words replacing the gravitational energy with tidal energy, or an underwater ramp pump system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus one would be able to pump water to an extensive height, without using fossil fuel energy. &lt;/p&gt;&#xA;" OwnerUserId="9586" LastEditorUserId="94" LastEditDate="2017-08-10T17:10:12.857" LastActivityDate="2017-08-10T17:10:12.857" Title="Are ramp pumps the solution to the global water problem?" Tags="|hydrology|tides|gravity|" AnswerCount="0" CommentCount="5" ClosedDate="2017-08-12T19:47:21.060" ContentLicense="CC BY-SA 3.0" />
  <row Id="12051" PostTypeId="2" ParentId="10539" CreationDate="2017-08-10T13:32:51.303" Score="0" Body="&lt;p&gt;When water is infiltrating an aquifer system which contains an unsaturated zone (vadose zone), whether from an infiltration bassin or a river, The first centimeters usually are saturated, the bottom of this saturated layer is called the inverted water table because under the layer there is a soil which is not completely saturated. &lt;/p&gt;&#xA;" OwnerUserId="10689" LastActivityDate="2017-08-10T13:32:51.303" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12052" PostTypeId="1" CreationDate="2017-08-10T17:41:30.700" Score="1" ViewCount="154" Body="&lt;p&gt;Density is 19.25 g/cm3, hardness ~9 (Tungsten carbide might apply), and melting point is at 3695 K.&lt;/p&gt;&#xA;" OwnerUserId="10751" LastEditorUserId="10751" LastEditDate="2017-08-11T13:25:43.170" LastActivityDate="2017-08-11T15:45:14.053" Title="How big does a pointed piece of tungsten need to be to self-propel into the earths core by gravity alone?" Tags="|hypothetical|" AnswerCount="2" CommentCount="3" ClosedDate="2017-08-12T23:49:30.340" ContentLicense="CC BY-SA 3.0" />
  <row Id="12053" PostTypeId="1" CreationDate="2017-08-10T20:36:28.217" Score="7" ViewCount="1876" Body="&lt;p&gt;Im a bit confused on how crucial Nitrogen fixation with the Haber-Bosch process really was. On the &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Haber_process&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia page of the Haber-Bosch process&lt;/a&gt; it says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In combination with pesticides, these fertilizers have quadrupled the&#xA;productivity of agricultural land.&lt;/p&gt;&#xA;&lt;p&gt;With average crop yields remaining at the 1900 level the crop harvest&#xA;in the year 2000 would have required nearly four times more land and&#xA;the cultivated area would have claimed nearly half of all ice-free&#xA;continents, rather than under 15% of the total land area that is&#xA;required today.&lt;/p&gt;&#xA;&lt;p&gt;Due to its dramatic impact on the human ability to grow food, the&#xA;Haber process served as the &amp;quot;detonator of the population explosion&amp;quot;,&#xA;enabling the global population to increase from 1.6 billion in 1900 to&#xA;today's 7 billion.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;However I have read that the products &lt;a href=&quot;https://www.bio-suisse.ch/en/home.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;labelled &amp;quot;Bio&amp;quot; in the stores in Switzerland that don't use nitrogen fertilizers&lt;/a&gt; have only about 20% lower yields, which is a dramatically different number than what the Wikipedia page on the Haber-Bosch process claims (quadrupling of productivity).&lt;/p&gt;&#xA;&lt;p&gt;What am I missing? Did the nitrogen cycle change so much so that we don't need nitrogen fertilizer nowadays? Did new technology enable us to get similar yields without nitrogen fertilization? What explains these numbers? Was crop rotation an unknown concept in the 1900’s?&lt;/p&gt;&#xA;" OwnerUserId="7338" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2023-02-14T20:28:18.917" Title="Did the Haber-Bosch process enable the population explosion?" Tags="|agriculture|nitrogen|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="12054" PostTypeId="2" ParentId="12031" CreationDate="2017-08-10T22:35:43.927" Score="5" Body="&lt;p&gt;We are calculating $ET_0$ on a 10 minute basis and ran into the same problem on &lt;a href=&quot;http://lapalma.HDmeteo.com&quot; rel=&quot;noreferrer&quot;&gt;http://lapalma.HDmeteo.com&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can confirm this problem with the FAO formula. We are clipping negative hourly values to 0. This occurs during nighttime when there is no wind and the wind term does not compensate for the radiation term.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is true that during the night, with high humidity and absent wind the crops get wet due to dew. But dew should be collected by the pluviometer and not accounted for by negative $ET_0$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The weather stations from Davis with integrated $ET_0$ module seem to use clipping of negative values, too, as they never report $ET_0 &amp;lt; 0$ even with hourly granularity.&lt;/p&gt;&#xA;" OwnerUserId="10755" LastActivityDate="2017-08-10T22:35:43.927" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12055" PostTypeId="2" ParentId="12052" CreationDate="2017-08-11T03:05:56.673" Score="1" Body="&lt;p&gt;Yes, tungsten carbide does have a hardness of 9, but neither it nor diamond, which has a hardness of 10, are immune to wear from friction. It's how rough diamonds get transformed into cut diamonds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From personal experience of using tungsten carbide drill bits (chisel bits, cross bit &amp;amp; button bits) to drill holes in rock, the tungsten carbide wears out and needs continual sharpening. The harder the rock being drilled, the faster the rate of wear. Eventually each drill bit wears out &amp;amp; becomes so narrow that it can no longer be used and it must be replaced. Also, anyone who has had involvement with diamond drilling will confirm that diamond drill bits wear out when they drill rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The deepest holes ever drilled only go to a depth of just over 12 km. Those holes being the &lt;a href=&quot;https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kola Superdeep borehole&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Al_Shaheen_Oil_Field&quot; rel=&quot;nofollow noreferrer&quot;&gt;Al Shaeen oil hole&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Sakhalin-I&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sakhalin-1&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In trying to reach the Earth's core, the hole will deviate and not be dead straight and the drill bits and drill steels will need to deal with high lateral earth pressures at depth and increasingly high rock temperatures. &#xA;Additionally, tungsten carbide is had but brittle so it's uses are limited.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No-one yet has the technology to drill a hole into the Earth's mantle, let alone its core.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit: After the question was edited to clarify the tungsten spike would move by gravity alone.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nothing much will happen. Such a spike, regardless of it mass, will sink into soil or sand, but once it contacts denser material, such as rock, and unavoidable lateral earth pressures also squeeze on the spike, movement of the spike will stop and it will still be near the surface of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gravity alone will not provide such a spike with the energy it needs to split rock.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2017-08-11T15:45:14.053" LastActivityDate="2017-08-11T15:45:14.053" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12057" PostTypeId="1" AcceptedAnswerId="12061" CreationDate="2017-08-11T09:43:42.440" Score="21" ViewCount="69316" Body="&lt;p&gt;I have three txt files for longitude, latitude and temperature (or let's say three lists lon, lat, temp) from scattered weather station in the UK. I would like firstly to interpolate these data in order to get a nice colourful map of temperatures. Then, I would like to plot this interpolated temperature layer only over the land mask (thus over the british isles and not over the sea). Is that possible with Python and how?&lt;/p&gt;&#xA;" OwnerUserId="10670" LastEditorDisplayName="user1066" LastEditDate="2018-08-02T19:19:56.290" LastActivityDate="2018-08-02T19:19:56.290" Title="How to interpolate scattered data to a regular grid in Python?" Tags="|meteorology|temperature|python|interpolation|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12058" PostTypeId="2" ParentId="12057" CreationDate="2017-08-11T10:38:46.427" Score="0" Body="&lt;p&gt;First you would have to read the data for example in matlab. Then you can get the whole field interpolated with the function griddata in matlab. And there also exist a landmask -function that allows you to further plot a map of your liking.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So yes this is possible and there are the necessary functions at least in matlab and I would guess that in other languages too.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastActivityDate="2017-08-11T10:38:46.427" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12059" PostTypeId="2" ParentId="12057" CreationDate="2017-08-11T12:35:18.487" Score="13" Body="&lt;p&gt;You have a lot of options.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The easiest solution for this simple task would be to use a GIS software, e.g. the free &lt;a href=&quot;http://www.qgis.org/en/site/&quot; rel=&quot;noreferrer&quot;&gt;QGIS&lt;/a&gt;. Add delimited text layer and try raster interpolation. Download a &lt;a href=&quot;http://www.diva-gis.org/gdata&quot; rel=&quot;noreferrer&quot;&gt;free coastline vector&lt;/a&gt; and clip your raster with the coastline. A few searches at &lt;a href=&quot;https://gis.stackexchange.com/&quot;&gt;GIS SE&lt;/a&gt; can help you out if you get stuck. With a GIS option, it is easy to also plot e.g. cities or extract the interpolated temperature for a location. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alternatively (according to your updated question), you can use Python. This will somehow give you more control of your workflow. &lt;a href=&quot;https://matplotlib.org/basemap/&quot; rel=&quot;noreferrer&quot;&gt;Basemap&lt;/a&gt; is a useful package, see e.g. &lt;a href=&quot;http://earthpy.org/interpolation_between_grids_with_basemap.html&quot; rel=&quot;noreferrer&quot;&gt;this tutorial&lt;/a&gt; for a start. Python is also free and there is a great community at &lt;a href=&quot;https://stackoverflow.com/questions/tagged/python&quot;&gt;SE&lt;/a&gt; and elsewhere. numpy and scipy are good packages for interpolation and all array processes. For more complicated spatial processes (clip a raster from a vector polygon e.g.) &lt;a href=&quot;http://www.gdal.org/&quot; rel=&quot;noreferrer&quot;&gt;GDAL&lt;/a&gt; is a great library. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can also use &lt;a href=&quot;https://www.r-project.org/about.html&quot; rel=&quot;noreferrer&quot;&gt;R&lt;/a&gt;, that might be a smart solution if you intend to do some more demanding statistical analysis later. There are &lt;a href=&quot;http://www.milanor.net/blog/maps-in-r-plotting-data-points-on-a-map/&quot; rel=&quot;noreferrer&quot;&gt;some tutorials&lt;/a&gt; that can put you on the right track. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://gmt.soest.hawaii.edu/&quot; rel=&quot;noreferrer&quot;&gt;GMT&lt;/a&gt; should also able to make what you need and there is a &lt;a href=&quot;https://github.com/GenericMappingTools/gmt-python&quot; rel=&quot;noreferrer&quot;&gt;python interface&lt;/a&gt;, at least under development. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Probably, you'd like to spend some effort on picking the right interpolation method and make sure that your grid is the best estimate for the actual values. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Enjoy your map-making! &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Update: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think that GIS would be the first approach, but as you asked for some Python commands, here is a sloppy example of how to use Python, basemap and scipy for your application. It can be greatly improved by creating a mask from a shapefile and, as mentioned, a sensitive use of interpolation method. &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;import numpy as np&#xA;from scipy.interpolate import griddata&#xA;from mpl_toolkits.basemap import Basemap&#xA;import matplotlib.pyplot as plt&#xA;&#xA;#Define mapframe&#xA;lllon = -11&#xA;lllat = 49&#xA;urlon = 2&#xA;urlat = 61&#xA;&#xA;# Make some toy data, random points + corners&#xA;n = 10 # no of stations&#xA;lat = np.random.uniform(low=lllat+2, high=urlat-2, size=n)&#xA;lat = np.append(lat, [lllat, urlat, urlat, lllat]) &#xA;lon = np.random.uniform(low=lllon+2, high=urlon-2, size=n)&#xA;lon = np.append(lon, [lllon, urlon, lllon, urlon])&#xA;temp = np.random.randn(n+4) + 8 # British summer?&#xA;&#xA;# set up basemap chose projection!&#xA;m = Basemap(projection = 'merc', resolution='i', &#xA;    llcrnrlon = lllon, llcrnrlat = lllat, urcrnrlon = urlon, urcrnrlat = urlat) &#xA;&#xA;# transform coordinates to map projection m&#xA;m_lon, m_lat = m(*(lon, lat))&#xA;&#xA;# generate grid data&#xA;numcols, numrows = 240, 240&#xA;xi = np.linspace(m_lon.min(), m_lon.max(), numcols)&#xA;yi = np.linspace(m_lat.min(), m_lat.max(), numrows)&#xA;xi, yi = np.meshgrid(xi, yi)&#xA;&#xA;# interpolate, there are better methods, especially if you have many datapoints&#xA;zi = griddata((m_lon,m_lat),temp,(xi,yi),method='cubic')&#xA;&#xA;fig, ax = plt.subplots(figsize=(12, 12))&#xA;&#xA;# draw map details&#xA;m.drawmapboundary(fill_color = 'skyblue', zorder = 1)&#xA;&#xA;# Plot interpolated temperatures&#xA;m.contourf(xi, yi, zi, 500, cmap='magma', zorder = 2)&#xA;&#xA;m.drawlsmask(ocean_color='skyblue', land_color=(0, 0, 0, 0), lakes=True, zorder = 3)&#xA;&#xA;cbar = plt.colorbar()&#xA;plt.title('Temperature')&#xA;&#xA;plt.show()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(This is modified code, used for something else. For detailed questions, other forums are more suitible. )&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RoDgb.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RoDgb.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2536" LastEditorUserId="2536" LastEditDate="2017-08-13T15:52:39.450" LastActivityDate="2017-08-13T15:52:39.450" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="12060" PostTypeId="2" ParentId="12052" CreationDate="2017-08-11T14:51:31.723" Score="2" Body="&lt;p&gt;It will never get past the mantle. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The tungsten (or tungsten carbide) will chemically react with the rocks surrounding it to dissolve and form other minerals (silicates), or even worse: get diluted to trace levels in mantle minerals. Compare this with dropping some grains of salt in the ocean and asking when they will arrive to the sea floor. Your block&#xA;of tungsten will probably need to be on the scale of tens of metres or more (km?) to escape that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, the mantle is convecting so it will keep your thing from sinking directly down. Compare with leaves falling from a tree in a thunderstorm. This will encourage the chemical mixing I mentioned before.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-08-11T14:51:31.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12061" PostTypeId="2" ParentId="12057" CreationDate="2017-08-11T18:37:51.740" Score="28" Body="&lt;p&gt;It is straightforward to do so with &lt;code&gt;numpy&lt;/code&gt;, &lt;code&gt;scipy.interpolate.griddata&lt;/code&gt;, and &lt;code&gt;matplotlib&lt;/code&gt;. Here is an example:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;import matplotlib.pyplot as plt&#xA;import numpy as np&#xA;from scipy.interpolate import griddata&#xA;&#xA;# data coordinates and values&#xA;x = np.random.random(100)&#xA;y = np.random.random(100)&#xA;z = np.random.random(100)&#xA;&#xA;# target grid to interpolate to&#xA;xi = yi = np.arange(0,1.01,0.01)&#xA;xi,yi = np.meshgrid(xi,yi)&#xA;&#xA;# set mask&#xA;mask = (xi &amp;gt; 0.5) &amp;amp; (xi &amp;lt; 0.6) &amp;amp; (yi &amp;gt; 0.5) &amp;amp; (yi &amp;lt; 0.6)&#xA;&#xA;# interpolate&#xA;zi = griddata((x,y),z,(xi,yi),method='linear')&#xA;&#xA;# mask out the field&#xA;zi[mask] = np.nan&#xA;&#xA;# plot&#xA;fig = plt.figure()&#xA;ax = fig.add_subplot(111)&#xA;plt.contourf(xi,yi,zi,np.arange(0,1.01,0.01))&#xA;plt.plot(x,y,'k.')&#xA;plt.xlabel('xi',fontsize=16)&#xA;plt.ylabel('yi',fontsize=16)&#xA;plt.savefig('interpolated.png',dpi=100)&#xA;plt.close(fig)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Result:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AMWOC.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AMWOC.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How to use this:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;code&gt;x&lt;/code&gt; and &lt;code&gt;y&lt;/code&gt; are locations of points - these correspond to &lt;code&gt;lon&lt;/code&gt; and &lt;code&gt;lat&lt;/code&gt; values of your stations;&lt;/li&gt;&#xA;&lt;li&gt;&lt;code&gt;z&lt;/code&gt; are the values of points - this corresponds to your temperature observations from stations;&lt;/li&gt;&#xA;&lt;li&gt;&lt;code&gt;xi&lt;/code&gt; and &lt;code&gt;yi&lt;/code&gt; are target grid axes - these will be your target longitude and latitude coordinates, which must match your landmask field;&lt;/li&gt;&#xA;&lt;li&gt;&lt;code&gt;zi&lt;/code&gt; is the result;&lt;/li&gt;&#xA;&lt;li&gt;This example includes a simple way to mask the field. You should replace this mask with the landmask on your grid.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Notice also the &lt;code&gt;method&lt;/code&gt; argument to &lt;code&gt;griddata&lt;/code&gt;. Besides &lt;code&gt;linear&lt;/code&gt;, this can also be &lt;code&gt;cubic&lt;/code&gt; or &lt;code&gt;nearest&lt;/code&gt;. I suggest you play with each to see what yields the best result for your dataset.&lt;/p&gt;&#xA;" OwnerUserId="192" LastActivityDate="2017-08-11T18:37:51.740" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="12062" PostTypeId="1" CreationDate="2017-08-11T19:17:31.217" Score="1" ViewCount="96" Body="&lt;p&gt;Are fluctuations like El Niño and La Niña entirely independent of outside influences such as the gravitational effects from other planets, variation in solar output, etc?&lt;/p&gt;&#xA;" OwnerUserId="10761" LastEditorUserId="6298" LastEditDate="2017-08-11T22:17:40.043" LastActivityDate="2017-08-12T20:56:20.993" Title="Are Earth´s interannual global climate variations affected by other bodies in the solar system and their evolution?" Tags="|climate-change|climate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12063" PostTypeId="2" ParentId="4390" CreationDate="2017-08-11T20:13:40.247" Score="1" Body="&lt;p&gt;I believe it is not very useful while FDC's  are mostly interesting for the entire discharge record. You can zoom in to the lower part of the curve and analyse it. The problem with the FDC is that it give no indication of sequences of low flows.&#xA;You can imagine a river with no discharge (=0) during a couple of months for example. With monthly minimum values this problem is smaller. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the end I believe it's more useful to use probability distributions for frequency analysis of extreme values like low flows. In literature you can find that the Gumbel distribution of the smallest value is one of the most reliable for annual minimum flows. &lt;/p&gt;&#xA;" OwnerUserId="10681" LastEditorUserId="10681" LastEditDate="2017-08-21T17:34:30.640" LastActivityDate="2017-08-21T17:34:30.640" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12064" PostTypeId="2" ParentId="7883" CreationDate="2017-08-11T20:21:55.533" Score="3" Body="&lt;p&gt;The rational method is especially usefull for small areas. For larger catchments it is less accurate. Then you should use a rainfall-runoff model but that is only possible when you have sufficient data. A more simple method is the use of runoff coefficients. Maybe something like the SCS method.&lt;/p&gt;&#xA;" OwnerUserId="10681" LastActivityDate="2017-08-11T20:21:55.533" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12065" PostTypeId="1" CreationDate="2017-08-11T21:30:51.130" Score="2" ViewCount="58" Body="&lt;p&gt;It is repeated often that Saharan calimas are fertilizing often Atlantic ocean. But I suppose that most of Saharan dust contains Fe&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; and not FeO. Am I right?&lt;/p&gt;&#xA;" OwnerUserId="10761" LastEditorUserId="725" LastEditDate="2017-08-12T22:49:13.680" LastActivityDate="2017-08-12T22:50:22.797" Title="Saharian calima dust, apart of Fe2O3 does contain FeO?" Tags="|geochemistry|geobiology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12066" PostTypeId="2" ParentId="12065" CreationDate="2017-08-12T00:43:19.207" Score="3" Body="&lt;p&gt;I think you are correct. Typical sand is silica (white) with a little Fe&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; (red) to give a &quot;sand&quot; color. FeO is black and over geological time in air, oxidizes further to Fe&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt; with hydroxides and hydrates (black and dark brown) and eventually Fe&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;. &lt;/p&gt;&#xA;" OwnerUserId="8409" LastEditorUserId="725" LastEditDate="2017-08-12T22:50:22.797" LastActivityDate="2017-08-12T22:50:22.797" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12067" PostTypeId="1" CreationDate="2017-08-12T10:36:51.720" Score="2" ViewCount="116" Body="&lt;p&gt;Is it not the Ekman Transport, or wind drag of the surface water,  a violation of the Physical evidence of zero relative velocity at any boundary, in viscous flow?&lt;/p&gt;&#xA;" OwnerUserId="10761" LastEditorUserId="2536" LastEditDate="2017-08-12T14:05:14.443" LastActivityDate="2017-08-24T10:12:17.947" Title="Ekman Transport" Tags="|oceanography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12069" PostTypeId="1" CreationDate="2017-08-12T13:19:02.533" Score="1" ViewCount="216" Body="&lt;p&gt;The thermohaline current in the North Atlantic ocean sinks because it gets cooled, or it gets cooled because of sinking?&lt;/p&gt;&#xA;" OwnerUserId="10761" LastEditorUserId="2536" LastEditDate="2017-08-12T14:04:28.263" LastActivityDate="2017-08-24T12:26:26.017" Title="Thermohaline current in North Atlantic" Tags="|oceanography|ocean-currents|salinity|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12071" PostTypeId="1" CreationDate="2017-08-12T15:12:40.340" Score="0" ViewCount="175" Body="&lt;p&gt;How is it possible that Mauna Loa Observatory is the International Reference Observatory for CO&lt;sub&gt;2&lt;/sub&gt; Global Measurements if it is placed above the most important earth thermal plume that is heating the ocean all the year? How reliable can these data be? Is it due to the 3000 m altitude of the Observatory? Does not affect the geological Hawaiian situation?&lt;/p&gt;&#xA;" OwnerUserId="10761" LastEditorUserId="94" LastEditDate="2017-08-13T16:09:17.733" LastActivityDate="2017-08-13T16:14:57.610" Title="Is the Mauna Loa CO$_\mathsf{2}$ record affected by the nearby mantle plume?" Tags="|atmosphere|climate-change|climate|co2|mantle-plumes|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12072" PostTypeId="2" ParentId="12062" CreationDate="2017-08-12T20:56:20.993" Score="7" Body="&lt;p&gt;Short answer:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's probably very little effect, but &quot;entirely independent&quot; is another matter entirely.   There might be some small effect on a year to year, or, for sake of argument, 12 year orbital period of Jupiter.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Long answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The precise cause and predictability of (El Nino/La Nina and Neutral), or, &lt;a href=&quot;https://www.climate.gov/news-features/blogs/enso/what-el-ni%C3%B1o%E2%80%93southern-oscillation-enso-nutshell&quot; rel=&quot;noreferrer&quot;&gt;lets call it ENSO&lt;/a&gt; remains inexact and it's at best, a complex combination of causes and feedbacks.  I'm not precisely sure if it's simply complicate or there are still some unknowns that make any kind of longer term prediction very difficult.  I suspect there's still some unknowns and uncertainty in the longer term causes of ENSO.  This is a &lt;a href=&quot;http://www.nature.com/ngeo/journal/v3/n6/full/ngeo868.html?foxtrotcallback=true&quot; rel=&quot;noreferrer&quot;&gt;pay article&lt;/a&gt;, in the summary it says.  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Year-to-year ENSO variability is controlled by a delicate balance of&#xA;  amplifying and damping feedbacks&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The immediate cause for ENSO seems to be weakening or strengthening of easterly, equatorial, &lt;a href=&quot;https://www.ncdc.noaa.gov/teleconnections/enso/enso-tech.php&quot; rel=&quot;noreferrer&quot;&gt;Pacific trade winds&lt;/a&gt;.   This makes El Ninos, La Nina's or &quot;Neutral&quot; predictable up to several months in advance but they remain very hard to predict further out than that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;ENSO &lt;a href=&quot;http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/eln/elyr.rxml&quot; rel=&quot;noreferrer&quot;&gt;Explained here&lt;/a&gt; with pictures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and while I generally hate the website, Wattsupwiththat, if you ignore their climate model discussion, their &lt;a href=&quot;https://wattsupwiththat.com/2014/02/23/el-nino-and-la-nina-basics-introduction-to-the-pacific-trade-winds/&quot; rel=&quot;noreferrer&quot;&gt;trade wind article&lt;/a&gt; is pretty good and the picture below gives a good summary of why trade winds control Pacific surface temperature.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/y7ygg.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/y7ygg.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, just to clarify &lt;a href=&quot;https://en.wikipedia.org/wiki/Wind_direction&quot; rel=&quot;noreferrer&quot;&gt;&quot;Easterly&quot; winds blow West&lt;/a&gt;.  The term means the winds come from the East, just as Northerly winds blow south.   That's why the diagram has easterly's blowing towards Indonesia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The next logical question is, what causes trade winds to weaken and strengthen and as noted above, that's complicated.  This article says the El Ninos occur &lt;a href=&quot;http://blogs.ei.columbia.edu/2016/02/02/el-nino-and-global-warming-whats-the-connection/&quot; rel=&quot;noreferrer&quot;&gt;every 2 to 7 years&lt;/a&gt;, which, while generally cyclical, is a pretty irregular period. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SFs5o.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SFs5o.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And &lt;a href=&quot;http://www.smithsonianmag.com/science-nature/corals-show-how-pacific-trade-winds-guide-global-temperatures-180953703/&quot; rel=&quot;noreferrer&quot;&gt;This article&lt;/a&gt; describes the cycle as &quot;flipping and flopping&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Trade_winds#Cause&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia touches on the cause&lt;/a&gt; of trade winds, but not on the precise mechanisms which strengthen or weaken them.   If the planets, presumably Jupiter being the primary one, has a significant effect, then it's 12 year orbital period should be have a detectable effect and I've never read anything to suggest that it does.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Jupiter does, very slightly affect Earth's orbit and Earth's orbit affects Earth's climate but the effect is small on a 12 year (1 Jupiter orbit) basis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth, relative to the sun, is basically in the &lt;a href=&quot;https://www.google.com/search?q=Earth%27s%20orbit%20winter%20summer&amp;amp;source=lnms&amp;amp;tbm=isch&amp;amp;sa=X&amp;amp;ved=0ahUKEwih5dvCvNLVAhUh2oMKHfICDC8Q_AUICigB&amp;amp;biw=1366&amp;amp;bih=628#imgrc=GG_lQLP-OBF3wM:&quot; rel=&quot;noreferrer&quot;&gt;same position every season&lt;/a&gt;.   Jupiter moves more slowly, so for practical purposes it can be viewed as relatively stationary.    When the Earth is behind Jupiter, it moves through it's orbit a little faster.   When it's ahead of Jupiter, it slows down a little bit.   Also, Jupiter has a tidal effect, where, Earth's orbit stretches in the direction of Jupiter.   These kinds of changes in orbital speed were observed in Uranus and lead to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Discovery_of_Neptune&quot; rel=&quot;noreferrer&quot;&gt;discovery of the planet Neptune&lt;/a&gt;.  For similar reasons,  Jupiter does have an effect on Earth's orbit depending on which side of the solar system it's on, but the effect is small.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll skip the math cause I don't do it well enough and it would get long and ugly, but a rough calculation puts an upper limit of the Jupiter effect on Earth's climate as 1/20th of 1% of solar radiation over a few years and then a return in the other direction a few years later, and that's peak season variation, not over a full year.   If winter gets 1/20th of 1% less radiation from the sun, or Summer, 1/20th of more is 1/20th of 1% colder might have a small effect, but not a big one.   That's less than the TSI variation of the sunspot cycle which peaks at about 1/10th of 1% and lasts longer.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've never heard it argued that Sunspots drive the ENSO cycle, though there is probably some small effect with that too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of-course, over much longer periods, Jupiter and to a lesser extent, Saturn likely do effect Earth's ENSO cycle, because Jupiter and Saturn drive Earth's &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;noreferrer&quot;&gt;Milankovich cycles&lt;/a&gt;, but those happen over periods of 20,000 years and up.   I don't see any way that the 12 year Jupiter orbit has anything more than a very tiny effect.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2017-08-12T20:56:20.993" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12073" PostTypeId="2" ParentId="12071" CreationDate="2017-08-12T21:29:29.093" Score="13" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;How is ist possible that Mauna Loa Observatory is the International Reference Observatory for CO2 Global Meassurments&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I don’t know that it &lt;em&gt;is&lt;/em&gt; ‘the International Reference Observatory’. The Mauna Loa record is almost certainly the most-cited decadal-scale CO&lt;sub&gt;2&lt;/sub&gt; record, but as far as I know the observatory hasn't been accorded any special status: the record is used on its own merits. Googling for the phrase ‘International Reference Observatory’ gave me precisely one hit, which strongly suggests that it's not a well-defined term. The hit comes from Roussel-Debet &lt;em&gt;et al.&lt;/em&gt; (2006), and appears in the following context:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;… the atmospheric CO&lt;sub&gt;2&lt;/sub&gt; values measured at the international reference observatory at Mauna Loa (Fig. 5)…&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Note the lack of capitalization. I don’t think that this implies the existence of a single, officially defined ‘International Reference Observatory’ at Mauna Loa. Rather, it's like writing ‘the solar observatory at Mauna Loa’: there are many solar observatories, and this clarifies which one we're talking about. Similarly, there are several observatories which produce internationally used CO&lt;sub&gt;2&lt;/sub&gt; data, and this specifies which one we’re talking about here.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;if it is placed above the most important earth thermal plume that is heating the ocean all the year?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It’s true that there is a posited mantle plume below Hawaii, so it seems likely that there might be increased thermal heat flux at the sea-floor. (Incidentally, I’m not sure what would make this mantle plume ‘the most important’, or even how one would quantify the importance of a mantle plume.) However, Von Herzen et al. (1989) found that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;… even though there is a small increase in heat flow with age along the swell, when compared with the off-swell heat flux, the anomalous heat flow associated with the Hawaiian Swell is probably of the order of 5–10 mW m&lt;sup&gt;−2&lt;/sup&gt; and arguably may not exist at all.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But more to the point: even if there is slightly increased heat flux here, why do you think it would affect the CO&lt;sub&gt;2&lt;/sub&gt; readings? What mechanism are you suggesting by which a small amount of conducted heat, several kilometres below sea level, is able to perturb atmospheric CO&lt;sub&gt;2&lt;/sub&gt; concentrations several kilometres &lt;em&gt;above&lt;/em&gt; sea level?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally: even if there were such a mechanism, the mantle plume operates, as you point out, ‘all the year’ – year in, year out, for millenia before the Mauna Loa station even existed. So at worst it would produce a constant offset, and wouldn't affect the trend of the measured CO&lt;sub&gt;2&lt;/sub&gt; concentrations.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How reliable can these data be?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Very reliable indeed! Look at this comparison with records from Samoa, Barrow, and the South Pole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XwZ9o.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XwZ9o.png&quot; alt=&quot;CO2 trend comparison&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;Source: &lt;a href=&quot;http://www.noaa.gov/sites/default/files/styles/watermark/public/thumbnails/image/co2_mm_obs.png?itok=4bWQwfEa&quot; rel=&quot;noreferrer&quot;&gt;NOAA&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Naturally, the shape of the annual cycle varies depending on the measuring station's latitude (you can see that the South Pole record is out of phase with the northern hemisphere records, as you'd expect), but the trends are an indisputably excellent match. If there were some confounding local influence at Mauna Loa, we certainly wouldn't see it reproduced at other sites thousands of kilometres away.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is it due to the 3000 m altitude of the Observatory?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That's certainly one factor that makes Mauna Loa an excellent site for this kind of study. &lt;a href=&quot;https://www.skepticalscience.com/print.php?r=196&quot; rel=&quot;noreferrer&quot;&gt;This Skeptical Science page&lt;/a&gt; lists some others:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Early attempts to measure CO2 in the USA and Scandinavia found that the readings varied a lot due to the influence of growing plants and the exhaust from motors. Mauna Loa is ideal because it is so remote from big population centres. Also, on tropical islands at night, the prevailing winds blow from the land out to sea, which effect brings clean, well-mixed Central Pacific air from high in the atmosphere to the observatory. This removes any interference coming from the vegetation lower down on the island.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;For more detail on how measurements are taken at Mauna Loa, and how the data is checked to make sure that it’s not contaminated by local influences, see &lt;a href=&quot;https://www.esrl.noaa.gov/gmd/ccgg/about/co2_measurements.html&quot; rel=&quot;noreferrer&quot;&gt;this detailed NOAA page on measurement procedures&lt;/a&gt;. The &lt;a href=&quot;https://www.esrl.noaa.gov/gmd/ccgg/about/co2_measurements.html#data_selection&quot; rel=&quot;noreferrer&quot;&gt;section on ‘Data selection for background air’&lt;/a&gt; is particularly relevant to your question. (Thanks to jeffronicus for providing this link in the comments.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to your final question:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Does not affect the geological Hawaiian situation?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I assume that you meant to write ‘Does the Hawaiian geological situation not affect the readings?’. I hope I’ve made it clear that it doesn’t, and that Mauna Loa is so widely used precisely because of the &lt;em&gt;absence&lt;/em&gt; of local influences on the readings.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sylvie Roussel-Debet, Gilles Gontier, Françoise Siclet, Marc Fournier, Distribution of carbon 14 in the terrestrial environment close to French nuclear power plants, &lt;em&gt;Journal of Environmental Radioactivity&lt;/em&gt;, Volume 87, Issue 3, 2006, Pages 246–259, ISSN 0265-931X, doi:&lt;a href=&quot;http://doi.org/10.1016/j.jenvrad.2005.12.002&quot; rel=&quot;noreferrer&quot;&gt;10.1016/j.jenvrad.2005.12.002&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Von Herzen, R. P., M. J. Cordery, R. S. Detrick, and C. Fang (1989), Heat flow and the thermal origin of hot spot swells: The Hawaiian Swell revisited, &lt;em&gt;Journal of Geophysical Research&lt;/em&gt;, 94(B10), 13783–13799, doi:&lt;a href=&quot;http://doi.org/10.1029/JB094iB10p13783&quot; rel=&quot;noreferrer&quot;&gt;10.1029/JB094iB10p13783&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2017-08-13T16:14:57.610" LastActivityDate="2017-08-13T16:14:57.610" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12075" PostTypeId="1" AcceptedAnswerId="13253" CreationDate="2017-08-13T13:28:07.977" Score="14" ViewCount="378" Body="&lt;p&gt;The Guardian article &lt;a href=&quot;https://www.theguardian.com/world/2017/aug/12/scientists-discover-91-volcanos-antarctica&quot; rel=&quot;noreferrer&quot;&gt;Scientists discover 91 volcanoes below Antarctic ice sheet&lt;/a&gt; highlights a recently published &lt;a href=&quot;http://www.ed.ac.uk/geosciences&quot; rel=&quot;noreferrer&quot;&gt;University of Edinburgh School of Geosciences&lt;/a&gt; discovery and cataloging of over ninety new volcanos under the Antarctic ice sheet. &lt;em&gt;A new volcanic province: an inventory of subglacial volcanoes in West Antarctica&lt;/em&gt; by Maximillian van Wyk de Vries, Robert G. Bingham and Andrew S. Hein, Geological Society, London, Special Publications, 461, 29 May 2017, &lt;a href=&quot;https://doi.org/10.1144/SP461.7&quot; rel=&quot;noreferrer&quot;&gt;https://doi.org/10.1144/SP461.7&lt;/a&gt; &lt;strong&gt;note:&lt;/strong&gt; the article is Open Access!&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;edit:&lt;/strong&gt; ...by clicking through the Lyell collection to here: &lt;a href=&quot;http://sp.lyellcollection.org/content/early/2017/05/26/SP461.7&quot; rel=&quot;noreferrer&quot;&gt;http://sp.lyellcollection.org/content/early/2017/05/26/SP461.7&lt;/a&gt; and then again to view the PDF &lt;a href=&quot;http://sp.lyellcollection.org/content/early/2017/05/26/SP461.7.full-text.pdf&quot; rel=&quot;noreferrer&quot;&gt;http://sp.lyellcollection.org/content/early/2017/05/26/SP461.7.full-text.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Below is a screenshot of figure 3, including a cropped subsection. If you open the figure in a new window you can view it at full size. In the subsection there are two rectangles with the word CONE above them. Below these words there are two traces. If I understand correctly, the lower trace is (for lack of better vocabulary) the surface of the Earth, and those cones have been identified as volcanos. However I believe the upper trace is the top of a layer of &lt;a href=&quot;https://en.wikipedia.org/wiki/Tephra&quot; rel=&quot;noreferrer&quot;&gt;tephra&lt;/a&gt;:.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Tephra&lt;/strong&gt; is fragmental material produced by a volcanic eruption regardless of composition, fragment size or emplacement mechanism.&lt;a href=&quot;https://i.stack.imgur.com/g2AvM.png&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Volcanologists also refer to airborne fragments as &lt;strong&gt;pyroclasts&lt;/strong&gt;. Once clasts have fallen to the ground they remain as tephra unless hot enough to fuse together into pyroclastic rock or tuff.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I'm trying to understand what might have happened here. the two cones are of the order of 10 km apart, and they extend above and below sea level. Was there an eruption below the ice which acted as a buffer and contained the ejecta? With some melting, some water below the ice could help it to flow over time and redistribute more evenly between the cones. Or would these volcanos just blow the ice away completely for an extended period of time and Southern Ocean currents could assist in the redistribution?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/g2AvM.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/g2AvM.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Pmq4B.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Pmq4B.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Fig. 3. (&lt;em&gt;repeated here in case the original is not easily legible on your device&lt;/em&gt;) The upper panel shows an echogram from NASA’s Icebridge mission (NSIDC 2014) that shows generally good agreement between a cone on the echogram and on the Bedmap2 data. The lower panel shows an echogram&#xA;from Corr &amp;amp; Vaughan (2008) with basal topography picking out two cones; the dark layer above the bed is tephra believed to have erupted around 2000 years ago.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-02-01T00:20:02.357" Title="What is likely to have happened with these newly discovered antarctic volcanos below the ice?" Tags="|volcanology|antarctic|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12077" PostTypeId="1" AcceptedAnswerId="12078" CreationDate="2017-08-14T03:46:34.900" Score="1" ViewCount="12899" Body="&lt;p&gt;We know our earth has 71% water and 29% land, but compared to that land and water, how much air do we have in our atmosphere?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I mean: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;How big is our atmosphere&lt;/li&gt;&#xA;&lt;li&gt;Is there any increase or decrease in the amount of atmosphere over time&lt;/li&gt;&#xA;&lt;li&gt;Is there any change in percentage of oxygen over time&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="10770" LastEditorUserId="6298" LastEditDate="2017-08-14T03:51:26.900" LastActivityDate="2022-09-14T22:15:16.373" Title="How much atmoshphere is there compared to land and water" Tags="|atmosphere|geography|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12078" PostTypeId="2" ParentId="12077" CreationDate="2017-08-14T08:57:57.180" Score="5" Body="&lt;p&gt;71% of Earth's &lt;strong&gt;surface&lt;/strong&gt; is covered with water and 29% land.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thinking in that regard, that's saying that on 29% of Earth's &quot;surface&quot; locations you have land below your feet, and in 71% of the locations, you have water.  So to continue in such terms, you'd then ask... ok, what percentage of Earth's surface locations would have air above them!?!  Well that's all of them.  So to if you're comparing it with those percentages, I guess you'd have to say it's another 100%.  Or, if we put them together into a full 3-dimensional surroundings at the surface, well it'd basically be 50% air, 36% water, 14% land.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But to compare how much of each there REALLY is, you need to include depth, getting some sort of 3 dimensional understanding of it.  But the picture that reveals is certainly not the picture we are used to from daily experience.  From the values I was able to find:&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;In terms of the room each takes up, the volume:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Surface water (oceans+lakes+rivers, glaciers, etc) is &lt;a href=&quot;https://en.wikipedia.org/wiki/Water_distribution_on_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;1.4 billion km³&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;The inside of the Earth is about &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;1 trillion = 1000 billion km³&lt;/a&gt; &lt;/li&gt;&#xA;&lt;li&gt;For the atmosphere, as mentioned in comments, it's a little more difficult, as the gases only gradually give way to space.  You find less and less gas as you go up, but there's no set spot where there is none, as some tiny amount is always floating off into space.  So where do you draw the line?  A commonly used boundary between the atmosphere and space is the &lt;a href=&quot;https://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_line&quot; rel=&quot;nofollow noreferrer&quot;&gt;Karman line&lt;/a&gt;.  This would lead to a volume of &lt;a href=&quot;https://www.vcalc.com/wiki/vCalc/Sphere+-+Shell+Volume?var-r=6471&amp;amp;var-t=100&amp;amp;var-r-unit=km&amp;amp;var-t-unit=km&quot; rel=&quot;nofollow noreferrer&quot;&gt;53 billion km³&lt;/a&gt; (&lt;a href=&quot;https://en.wikipedia.org/wiki/Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;using Earth's radius = 6371 km&lt;/a&gt;).  Note that only about half of that is in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Troposphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;troposphere&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Stratosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;stratosphere&lt;/a&gt;, which are perhaps the familiar zones of the atmosphere where weather and the ozone layer (and 95% of air molecules) reside.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;To compare these directly, the volume of land is 20+ times larger than the atmosphere (or 40+ times larger than the troposphere+stratosphere), and 750+ times larger than the Earth's water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or as percentages, the volume is:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Land 95.3%&lt;/li&gt;&#xA;&lt;li&gt;Air 5.6%,&lt;/li&gt;&#xA;&lt;li&gt;Ocean 0.1%&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Another useful way to look at is mass.  In terms of how much &lt;a href=&quot;https://en.wikipedia.org/wiki/Geosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;mass&lt;/a&gt; there is of each (&lt;a href=&quot;https://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;from NASA&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Atmosphere: $5.1\times10^{18}$ kg&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Geosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hydrosphere&lt;/a&gt;: $1.4\times10^{21}$ kg&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Geosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geosphere&lt;/a&gt;: $6.0\times10^{24}$ kg&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So there is 500+ times more water than air... and 4000+ times more &quot;land&quot; than water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or in percents, the mass is:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Land: 99.98%&lt;/li&gt;&#xA;&lt;li&gt;Water: 0.02%&lt;/li&gt;&#xA;&lt;li&gt;Air: 0.00008%&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;You could also look at the comparison in other ways, such as with the number of molecules.  But to save time, the answers will still typically boil down to the same idea: though land is the least of what we &lt;a href=&quot;https://www.nasa.gov/multimedia/imagegallery/image_feature_329.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;see around us on the surface&lt;/a&gt; (if you're a true global traveler), it is by far and away the greatest part of our planet overall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One final visualization that looks interesting is considering if we made giants balls of the air and water at Earth's surface... &lt;a href=&quot;http://boingboing.net/2008/03/11/all-the-water-and-ai.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;they'd actually be about the same size...  and nowhere close to the size of Earth&lt;/a&gt; (and that's even neglecting the fact that for fair comparison, the Earth, if somehow all of it could be brought to surface conditions, would be even larger due its current &lt;a href=&quot;https://en.wikipedia.org/wiki/Structure_of_the_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;internal compression&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;As to whether the amount of oxygen is changing, remember no element can be created or destroyed (aside from &lt;a href=&quot;https://en.wikipedia.org/wiki/Nuclear_reaction&quot; rel=&quot;nofollow noreferrer&quot;&gt;nuclear processes&lt;/a&gt;).  So the only way oxygen can change is if it is tied up in a &lt;a href=&quot;https://en.wikipedia.org/wiki/Nuclear_reaction&quot; rel=&quot;nofollow noreferrer&quot;&gt;compound&lt;/a&gt; or is removed into the ground or space.  In our lifetimes, there is very insignificant change overall, though it sounds like a notable amount is being &lt;a href=&quot;http://cdiac.ornl.gov/trends/oxygen/modern_records.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;used up each day in combustion reactions&lt;/a&gt; (see the part about oxygen depletion further down) [oxygen decreases from that, but since carbon dioxide has more mass, the overall atmospheric mass actually increases, just not the stuff you can breathe!].  If you're looking for a much longer history, it appears &lt;a href=&quot;https://www.britannica.com/topic/evolution-of-the-atmosphere-1703862&quot; rel=&quot;nofollow noreferrer&quot;&gt;this Britannica article&lt;/a&gt; gives a more thorough discussion of the factors in play and some of the changes that have occurred.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to the mass of the atmosphere over eons, I naively thought maybe less would be known about that... but articles in &lt;a href=&quot;https://www.scientificamerican.com/article/fossil-imprints-of-rain-reveal-early-earth-atmosphere/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scientific American&lt;/a&gt; and &lt;a href=&quot;http://www.nature.com/ngeo/journal/v9/n6/abs/ngeo2713.html?foxtrotcallback=true&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nature&lt;/a&gt; both hint the atmosphere was at much different pressures once upon a time (albeit reaching conclusions in opposite directions!)  Such changes in pressure would likely come with large differences in mass and/or volume of the atmosphere as well, but until someone shows me otherwise, those estimates would seem to be quite speculative.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And if we're going that direction, maybe we should just turn to &lt;a href=&quot;https://what-if.xkcd.com/12/&quot; rel=&quot;nofollow noreferrer&quot;&gt;What-If XKCD&lt;/a&gt;!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-08-14T11:13:36.577" LastActivityDate="2017-08-14T11:13:36.577" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12079" PostTypeId="2" ParentId="9867" CreationDate="2017-08-14T09:17:39.937" Score="3" Body="&lt;p&gt;Math is very important for hydrology. Especially for surface water problems, you require understanding of differential equations while open-water hydraulics like backwater calculations are complex. If you need a great deal of detail, these problems cannot be solved analytical, only numerical. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I recommend a good mathematical basis to study surface water hydrology and hydraulics.&lt;/p&gt;&#xA;" OwnerUserId="10681" LastEditorUserId="10681" LastEditDate="2018-09-15T19:05:08.830" LastActivityDate="2018-09-15T19:05:08.830" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="12080" PostTypeId="2" ParentId="12077" CreationDate="2017-08-14T12:41:00.573" Score="2" Body="&lt;p&gt;There is no absolute upper limit to the atmosphere there's only an arbitrary pressure cutoff at 100km up but the atmosphere is effectively unbreathable above six, six-and-a-half kilometers up. The troposphere, where almost everything we care about (like weather) happens, stops at ten kilometers up and contains 70-80% percent of the atmosphere by mass. Total atmospheric weight is 5.1480×10^18 kg plus or minus 1.5×10^15 kg of water vapour.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So all of that is fine but to get a real picture of how the atmosphere relates to the Earth one of my favourite yardsticks is to imagine the Earth is an apple, cut through the apple, the thin line of colour where the skin is? That's a little thicker in proportion than Earth's atmosphere. Hope that helps you with the scale and scope of the thing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Over geological time the atmosphere can and has changed dramatically, like the &lt;a href=&quot;https://simple.wikipedia.org/wiki/Great_Oxygenation_Event&quot; rel=&quot;nofollow noreferrer&quot;&gt;Great Oxygenation&lt;/a&gt; but on a human timescale it's basically stable. However there are certain changes that are almost immeasurably small that make a big difference, just 7 &lt;em&gt;parts per million&lt;/em&gt; of &lt;a href=&quot;https://en.wikipedia.org/wiki/Ozone_depletion&quot; rel=&quot;nofollow noreferrer&quot;&gt;ozone depletion&lt;/a&gt; is the difference between a working ozone layer and elevated skin cancer rates across the southern hemisphere.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="10735" LastEditDate="2017-08-14T13:12:39.383" LastActivityDate="2017-08-14T13:12:39.383" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12081" PostTypeId="2" ParentId="4346" CreationDate="2017-08-14T14:10:12.253" Score="0" Body="&lt;p&gt;Depends on your definition of &quot;plants&quot;, if you simply mean organisms using chloroplastic photosynthesis which is the most basic definition then the answer is almost all of it. If you want to know how much of the oxygen we breath is from land plants like trees and grasses the answer is roughly 55% annually with 45% being from phytoplankton blooms with trace amounts generated by UV radiation acting on water and certain nitrogen oxides in the upper atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's hard to say what a plant minimum for mammalian survival would look like because the availability of atmospheric oxygen would effect the interactions of that oxygen with the biosphere, hydrosphere, and lithosphere. Also which mammals? Mole-rats need significantly less oxygen per kilogram than humans which need less than mice.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2017-08-14T14:10:12.253" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12082" PostTypeId="2" ParentId="12069" CreationDate="2017-08-14T17:20:55.150" Score="1" Body="&lt;p&gt;It not only is cooled but saltwater sea ice separates fresh water in the ice forming heavier brine that drives the cold water circulation.&lt;/p&gt;&#xA;" OwnerUserId="9548" LastActivityDate="2017-08-14T17:20:55.150" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12083" PostTypeId="1" CreationDate="2017-08-14T19:07:37.210" Score="8" ViewCount="134" Body="&lt;p&gt;While I was reading how the EU taxes aviation companies based on carbon emissions it occurred to me that the effect of carbon emissions on global temperature etc. may depend on where the carbon is emitted. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: Is it the case that the effect of the release of carbon is dependent upon the location (environment) in which it was released? (For example I could imagine that if CO2 were to be released in a rainforest the effect on the &quot;global atmosphere&quot; would be different than if it were emitted in an already more saturated atmosphere with less potential to utilize (or process) CO2. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any reference to studies done on the effect of CO2 emissions relative to the environment in which it is emitted would be welcome.&lt;/p&gt;&#xA;" OwnerUserId="7822" LastEditorUserId="543" LastEditDate="2018-01-12T22:12:41.577" LastActivityDate="2018-01-12T22:12:41.577" Title="Is the impact of carbon emision dependent on the location on the earth?" Tags="|atmosphere|climate-change|climate|co2|ecology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12084" PostTypeId="1" AcceptedAnswerId="12102" CreationDate="2017-08-14T22:17:49.603" Score="1" ViewCount="428" Body="&lt;p&gt;For a large catchment (&gt;1000ha) I'm looking for some method to use a area reduction factor to adapt precipitation values. I have a large dataset of daily precipitation values but I have to use some kind of adaptation. I have don't enough data to calibrate a rainfall runoff model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have looked in some literature but there is little generally usable information. Does someone has a good reference for me? Thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="10681" LastEditorUserId="10681" LastEditDate="2018-04-19T17:27:05.160" LastActivityDate="2018-04-19T17:27:05.160" Title="Area reduction factor reference for precipitation" Tags="|hydrology|precipitation|rainfall|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12085" PostTypeId="2" ParentId="12083" CreationDate="2017-08-14T23:38:08.313" Score="6" Body="&lt;p&gt;The climate impacts of CO2 are not constrained to the location they are emitted, but rather the whole globe will feel the effects.  CO2 is a long-lived molecule that takes 100+ years to convert or deposit.  The troposphere, though, only takes months to mix.  There are longer times for mixing between the north/south hemispheres, (e.g. over a year), but it is still short relative to the lifetime of CO2 in the atmosphere.  Globally, you can expect about a 2% variance of CO2 distributions in the well-mixed troposphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a &lt;a href=&quot;https://www.atmos-chem-phys.net/17/3861/2017/acp-17-3861-2017.pdf&quot; rel=&quot;noreferrer&quot;&gt;recent paper&lt;/a&gt; on CO2 distribution from M. Diallo et al.: Global distribution of CO2 in the upper troposphere–stratosphere.  The image below (Fig 6a) shows CO2 distribution for different months in color while the isolines are for potential temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6HLEt.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6HLEt.png&quot; alt=&quot;CO2 Distribution&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2017-08-15T15:15:41.673" LastActivityDate="2017-08-15T15:15:41.673" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="12086" PostTypeId="2" ParentId="10088" CreationDate="2017-08-14T23:55:42.437" Score="1" Body="&lt;p&gt;This is not an explicit answer but might give you an idea. The US National Weather Service forecasters use a tool called GFE to create gridded forecasts, largely starting from raw model data. For most models, even those that have TCDC as an output field, the model sky cover grids are computed by GFE using RH at various levels. For a few of the high resolution mesoscale models, the sky grids use the model cloud cover field and the resulting values are either 0% or 100%. Thus a blend of these differing sources can be used to get a more nuanced output forecast.&lt;/p&gt;&#xA;" OwnerUserId="10672" LastActivityDate="2017-08-14T23:55:42.437" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12088" PostTypeId="2" ParentId="7446" CreationDate="2017-08-15T12:56:07.797" Score="5" Body="&lt;p&gt;510,100,000 square kilometers of &lt;a href=&quot;https://www.google.co.nz/search?q=earth+surface+area&amp;amp;oq=earth+surface+area&amp;amp;aqs=chrome..69i57.4295j0j1&amp;amp;sourceid=chrome&amp;amp;ie=UTF-8&quot; rel=&quot;nofollow noreferrer&quot;&gt;surface area&lt;/a&gt;, and a total of 1,386,000,000 cubic kilometers of &lt;a href=&quot;https://water.usgs.gov/edu/earthhowmuch.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;water&lt;/a&gt; gives you a 2.717 kilometer column of water across the whole planet if it was billiard ball smooth, but the same basic shape.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="10735" LastEditDate="2017-08-15T13:59:16.330" LastActivityDate="2017-08-15T13:59:16.330" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12089" PostTypeId="2" ParentId="8957" CreationDate="2017-08-15T13:01:02.423" Score="0" Body="&lt;p&gt;Old, AKA existing, deposits on the continental shelf are certainly possible and are an active target of the shelf mineral surveys in a number of countries but most current oceanic basins are too well oxygenated at depth for current deposits to be building up. &lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2017-08-15T13:01:02.423" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12090" PostTypeId="2" ParentId="12083" CreationDate="2017-08-15T15:19:20.387" Score="3" Body="&lt;p&gt;As a rule no, while sulfur and nitrogen compounds from industrial and vehicle exhaust have an immediate impact and a relatively fast deposition cycle and thus are extremely location sensitive carbon dioxide is relatively long lived in the atmosphere and too plentiful in discharge to be heavily effected by the &lt;em&gt;environment&lt;/em&gt; of discharge, assuming direct atmospheric discharge. If you pumped carbon dioxide discharge into water instead of the air then the atmospheric concentrations would be greatly effected by location, specifically temperature and algal uptake rates.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2017-08-15T15:19:20.387" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12091" PostTypeId="1" CreationDate="2017-08-15T19:15:20.077" Score="4" ViewCount="255" Body="&lt;p&gt;Concerning &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Uranium%E2%80%93thorium_dating&quot; rel=&quot;nofollow noreferrer&quot;&gt;Uranium-series dating&lt;/a&gt;&quot;, also known as &quot;Uranium-thorium dating&quot;. &#xA; Uranium is present in deposits, &quot;typically at levels of between a few parts per billion and few parts per million by weight&quot;, according to the wikipedia article on the subject.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an example, with carbon dating, the amount of carbon-14 originally present in any given sample is consistent with the amount of carbon-14 created by the activity of sunlight in the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How do we know how much uranium-234 was in any given sample of rock when it was created/deposited?&lt;/p&gt;&#xA;" OwnerUserId="10777" LastEditorUserId="2470" LastEditDate="2017-08-16T02:37:46.017" LastActivityDate="2017-08-17T15:54:06.133" Title="How do we know how much Uranium was in any given sample when it was deposited?" Tags="|geology|radioactivity|archaeology|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12092" PostTypeId="2" ParentId="7316" CreationDate="2017-08-15T19:49:23.280" Score="5" Body="&lt;p&gt;There is another factor not yet mentioned contributing to the effect you notice: global warming is related to the total cumulative amount of CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere, not to what we are emitting in this instance. &lt;em&gt;The atmospheric lifetime&lt;/em&gt; of CO&lt;sub&gt;2&lt;/sub&gt; is &lt;a href=&quot;https://en.wikipedia.org/wiki/Greenhouse_gas#Atmospheric_lifetime&quot; rel=&quot;nofollow noreferrer&quot;&gt;estimated to be of the order of 30–95 years&lt;/a&gt;, i.e. if we stop emitting now the warming will continue into the future before reaching a peak and declining.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you look at the Mauna Loa graph in &lt;a href=&quot;https://earthscience.stackexchange.com/a/7319/595&quot;&gt;Gordon's answer&lt;/a&gt;: the warming in year X is not related to the Y-value for X, but to the total area under the graph &#xA;to year X.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quoting from e.g. the PDF &lt;a href=&quot;http://www.law.uchicago.edu/files/files/Pierrehumbert%20paper.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cumulative Carbon and Just Allocation of the Global Carbon Commons&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Recent research has shown that the magnitude of climate change, as measured by global mean warming, is very well characterized by a simple metric&#xA;  known as cumulative carbon. Cumulative carbon is simply the net carbon&#xA;  emitted globally over the period of time during which human activities continue to contribute a net input of carbon (as CO&lt;sub&gt;2&lt;/sub&gt;) to the Earth system –&#xA;  more or less the duration of the fossil fuel era. The key results regarding cumulative carbon are as follows:&lt;br /&gt;&#xA;  • The global mean warming is linearly proportional to cumulative carbon.&lt;br /&gt;&#xA;  • The amount of warming at the time emissions cease is nearly independant of the emissions trajectory over which the cumulative carbon is emitted.&lt;br /&gt;&#xA;  • The amount of warming at the time emissions cease persists for about a thousand years, and declines only very gradually over the next ten thousand years, and still more slowly over the following several hundred thousand years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Other significant greenhouse gases, notably methane, also contribute to&#xA;  global warming, but these do not merit consideration on an equal footing&#xA;  with CO&lt;sub&gt;2&lt;/sub&gt;&#xA;  because their persistence in the atmosphere is so short. For example, methane has an atmospheric lifetime of only 12 year, so that we can&#xA;  delay methane controls for two centuries if we wish, and still get the full&#xA;  benefit of reduction of methane emissions within a few decades of implementation of controls. The same cannot be said for CO&lt;sub&gt;2&lt;/sub&gt;, as we shall see shortly. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;BTW The methane disappears by oxidation, with one of the reaction products being .... CO&lt;sub&gt;2&lt;/sub&gt; again.&lt;/p&gt;&#xA;" OwnerUserId="595" LastEditorUserId="595" LastEditDate="2017-08-17T12:20:42.007" LastActivityDate="2017-08-17T12:20:42.007" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12093" PostTypeId="1" AcceptedAnswerId="12196" CreationDate="2017-08-15T21:07:14.593" Score="8" ViewCount="8678" Body="&lt;p&gt;I've been struggling to find equations that express how many degrees of warming greenhouse gases contribute, given the composition of an atmosphere (and solar insolation).&lt;/p&gt;&#xA;&lt;p&gt;What I did find was the &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stefan–Boltzmann Law&lt;/a&gt;, and that wiki article has good equations about black body radiation. It shows how to get a value of &lt;span class=&quot;math-container&quot;&gt;$279 K = 6 °C = 43 °F$&lt;/span&gt; for the plain Earth with no atmosphere. Then to account for the albedo of Earth, the effective temperature is calculated at &lt;span class=&quot;math-container&quot;&gt;$255 K = −18 °C = -0.4 °F$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Then the article basically states what the real values are without presenting any more equations or explaining how to calculate it.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;However, long-wave radiation from the surface of the earth is partially absorbed and re-radiated back down by greenhouse gases, namely water vapor, carbon dioxide and methane. Since the emissivity with greenhouse effect (weighted more in the longer wavelengths where the Earth radiates) is reduced more than the absorptivity (weighted more in the shorter wavelengths of the Sun's radiation) is reduced, the equilibrium temperature is higher than the simple black-body calculation estimates. As a result, the Earth's actual average surface temperature is about 288 K (15 °C), which is higher than the 255 K effective temperature, and even higher than the 279 K temperature that a black body would have.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;And there were only 2 cites that only cited the fact that H&lt;sub&gt;2&lt;/sub&gt;O, CO&lt;sub&gt;2&lt;/sub&gt;, and CH&lt;sub&gt;4&lt;/sub&gt; are greenhouse gases.&lt;/p&gt;&#xA;&lt;p&gt;I've been searching for how to calculate the warming due to GHGs, but no luck. I'm really hoping someone can shed some light on this. I'm looking for an equation that takes into account atmospheric composition and probably the rotation rate of Earth (or whatever body), and of course the solar insolation.&lt;/p&gt;&#xA;&lt;p&gt;Please note I'm not really asking about climate change calculations. Climate change is more about how the atmospheric composition is &lt;strong&gt;changing&lt;/strong&gt; (namely GHG increases). I'm simply looking for equations that dictate the temperature based on a &lt;strong&gt;given/constant&lt;/strong&gt; composition of the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="2733" LastEditorUserId="2470" LastEditDate="2022-07-18T00:03:14.927" LastActivityDate="2022-07-18T00:03:14.927" Title="How can we calculate the temperature of the atmosphere, including the greenhouse effect?" Tags="|atmosphere|temperature|sun|solar-terrestrial-physics|greenhouse-gases|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="12094" PostTypeId="2" ParentId="12091" CreationDate="2017-08-16T02:30:50.970" Score="1" Body="&lt;p&gt;The chemistry of lead is very different from that of uranium and thorium. There are key kinds of rock that could not possibly have been formed with even the smallest amount of primordial lead. The lithophilic nature of uranium and thorium means that those same kinds of rock could easily have readily accepted primordial uranium or thorium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any lead in those kinds of rocks must necessarily be the result of decay of uranium or thorium after the rock formed.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-08-16T02:30:50.970" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12095" PostTypeId="2" ParentId="12091" CreationDate="2017-08-16T03:01:45.400" Score="1" Body="&lt;p&gt;The field of nuclear physics has established the &lt;a href=&quot;https://en.wikipedia.org/wiki/Radioactive_decay&quot; rel=&quot;nofollow noreferrer&quot;&gt;radioactive decay&lt;/a&gt; series for radioactive elements (see &lt;a href=&quot;https://www.boundless.com/physics/textbooks/boundless-physics-textbook/nuclear-physics-and-radioactivity-30/radioactivity-190/radioactive-decay-series-introduction-708-1301/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; as well).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unlike &lt;a href=&quot;https://en.wikipedia.org/wiki/Uranium-238&quot; rel=&quot;nofollow noreferrer&quot;&gt;Uranium 238&lt;/a&gt;, &lt;a href=&quot;http://www.nuclear-power.net/nuclear-power-plant/nuclear-fuel/uranium/uranium-234/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Uranium 234&lt;/a&gt; is not &lt;a href=&quot;http://www.nuclear-power.net/glossary/primordial-matter/&quot; rel=&quot;nofollow noreferrer&quot;&gt;primordial nuclide&lt;/a&gt;. It is a indirect decay product of Uranium 238.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By knowing what elements, and their isotopes, are present in rocks and how much of these isotopes are present, combined with the radioactive decay chain it is possible to determine the amount of Uranium 234 that was once present when the rocks formed.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-08-16T03:01:45.400" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12096" PostTypeId="1" CreationDate="2017-08-16T03:45:38.557" Score="4" ViewCount="177" Body="&lt;p&gt;The question &lt;a href=&quot;https://earthscience.stackexchange.com/q/7446/6031&quot;&gt;If the Earth was a smooth spheroid how deep would be the ocean?&lt;/a&gt; has an &lt;a href=&quot;https://earthscience.stackexchange.com/a/7448/6031&quot;&gt;excellent answer&lt;/a&gt; which explains the shape and surface area of an oblate spheroid before calculating the average depth of the Earth's surface water (about 2.7 km). The difference in radius, and surface area compared to a sphere look to be of the order of parts-per-thousand compared to a sphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But even within the approximation of an ellipsoid, the Earth's gravity is not uniform in direction nor magnitude, and so the assumption of a constant water depth from pole to equator may also require some correction of the order of parts-per-thousand.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How would one calculate the variation of depth of the water from pole to equator taking into account some kind of first order variation of gravitational force and rotational effects (centrifugal force) to get the shape of the &quot;water ellipsoid&quot;? Does it turn out that the thickness would end up being uniform because the Earth ellipsoid is already a response to rotational effects, or would there be a pole-to-equator variation in depth of order parts-per-thousand?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2017-08-16T04:31:09.360" LastActivityDate="2021-01-22T03:29:32.503" Title="What would be the depth variation of a &quot;water ellipsoid&quot; above a reference ellipsoid Earth?" Tags="|ocean|earth-rotation|gravity|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12098" PostTypeId="1" AcceptedAnswerId="12099" CreationDate="2017-08-16T19:48:34.980" Score="0" ViewCount="58" Body="&lt;p&gt;Has been observed any changes in the real sun´s size on ocassion of the 1979 solar storm event ? (after and before)&lt;/p&gt;&#xA;" OwnerUserId="10761" LastActivityDate="2017-08-16T22:53:13.193" Title="Changes in Real Solar size around 1979?" Tags="|solar-terrestrial-physics|astronomy|" AnswerCount="1" CommentCount="3" ClosedDate="2017-08-17T22:08:15.273" ContentLicense="CC BY-SA 3.0" />
  <row Id="12099" PostTypeId="2" ParentId="12098" CreationDate="2017-08-16T22:53:13.193" Score="1" Body="&lt;p&gt;No, no such changes have been observed. Laclare et al. (1996) summarize various published solar diameter data from observations made between 1970 and 1995. Here's Figure 6 from their paper.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lan51.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lan51.png&quot; alt=&quot;solar diameter variations&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see (and as Laclare et al. point out), solar semi-diameter has shown no significant variation during the measurement periods. Given their deviation from the other data sets, the Wittmann data seem rather suspect, but even they show absolutely no change between the 1972 and 1981 data points. In short, none of these data are consistent with the notion that solar diameter changed in 1979.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Laclare, F., Delmas, C., Coin, J. P., &amp;amp; Irbah, A. (1996). Measurements and variations of the solar diameter. &lt;em&gt;Solar Physics&lt;/em&gt;, 166(2), 211-229.&lt;/p&gt;&#xA;" OwnerUserId="94" LastActivityDate="2017-08-16T22:53:13.193" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12100" PostTypeId="1" CreationDate="2017-08-17T01:07:35.950" Score="2" ViewCount="556" Body="&lt;p&gt;So the Earth has a giant magnetic field we use to determine direction. The field roughly looks like a &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnetic_dipole&quot; rel=&quot;nofollow noreferrer&quot;&gt;magnetic dipole&lt;/a&gt;, but because the field is generated by a &lt;a href=&quot;https://earthscience.stackexchange.com/a/142/10784&quot;&gt;turbulent liquid dynamo&lt;/a&gt; near the Earth's core, it's not a perfect dipole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This leads me to believe that as you approach the magnetic north or south poles, your compass reading will become increasingly vague, and that there's probably a finite region near the pole where the compass direction rather randomly points some direction other than the pole itself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, as you near the pole of a perfect dipole, the component of the magnetic field tangent to the surface approaches a magnitude of zero. Because real-world compasses have friction, imperfect magnets, and so forth, there's surely some minimum field strength required to accurately move the compass magnet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, I know that the pole has &lt;a href=&quot;http://science.howstuffworks.com/environmental/earth/geophysics/question782.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;daily cycles&lt;/a&gt; as well as long-term movements. My guess is the daily cycles can be predicted with some kind of almanac or equation, and that travelers near the pole could receive periodic updates as to the center of the daily cycles so they could adjust their local declination accordingly. Still, there would be some kind of precision error here that might be significant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Between the three effects above (and possibly others I don't know about), I'm guessing there's a real-world limit on how close you can get to the exact magnetic pole before a real-world compass can no longer be trusted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How close can we get to the magnetic pole and still use a compass to determine direction?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To narrow the scope of the question, I'm thinking of a standard compass I can pick up at Walmart for like $10 (say, &lt;a href=&quot;https://www.walmart.com/ip/Ultimate-Survival-Technologies-Folding-Map-Compass/44553330&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one&lt;/a&gt;). However, answers regarding high-end compasses and very low-end compasses (like, a magnetized needle through a cork floating in water) would also be appreciated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, my question relates to humans using compasses for navigation, so if the answer is less than a few hundred meters, that's close enough to &quot;right on the pole&quot; for my purposes. At that point, you could simply look at the building or other landmark you're trying to find. Conversely, if the answer is several hundred miles, that would make it impossible to use traditional compass-based navigation between settlements near the magnetic pole.&lt;/p&gt;&#xA;" OwnerUserId="10784" LastActivityDate="2018-10-29T16:26:30.650" Title="How close to the magnetic poles will a compass be accurate?" Tags="|geomagnetism|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12101" PostTypeId="2" ParentId="12091" CreationDate="2017-08-17T04:41:59.637" Score="0" Body="&lt;p&gt;&lt;strong&gt;Lead and uranium have completely different electro-chemical properties&lt;/strong&gt;. So as David mentioned it does not matter how much uranium the sample had (as long as it is enough to measure) what matters is whether it contained any lead when it formed. Uranium and lead do not form the same kinds of bonds with other elements, so what you do is look for a uranium based crystal or uranium incorporating crystal. Crystals have a very regular bonding pattern, so you know when the crystal formed it was uranium and not lead, becasue lead cannot form those types of bonds with the smale materials uranium can. So when you find lead locked in those crystals you know it is because when it crystallized it was uranium and later decayed into lead. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most samples used are crystals for this reason. We pick materials that could not normally include lead, by doing this you can add up the total amount of lead and uranium and that will tell you how much uranium there was originally.    &lt;strong&gt;Zircon&lt;/strong&gt; is especially common for this becasue it will readily incorporate uranium but strongly rejects lead, so even if there is lead present in the solution (molten rock) in will not be incorporated into the crystal, because it is actively repelled by the crystal surface, thus insuring any lead you find came after the crystal was already solid and the repulsion could not push it out. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2017-08-17T15:54:06.133" LastActivityDate="2017-08-17T15:54:06.133" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12102" PostTypeId="2" ParentId="12084" CreationDate="2017-08-17T14:36:00.070" Score="2" Body="&lt;p&gt;The answer depends on whether your data is from a single gauge or a network of gauges, and whether you have storm tracking data or not. Sounds to me like you have daily precip at a single gauge without much more information. If you know the annual average precipitation in the basin then a simple area reduction factor (ARF) calculation is basically the ratio of the annual average gauge precipitation over the basin average. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not too familiar with the literature on this, but this &lt;a href=&quot;https://d2dtl5nnlpfr0r.cloudfront.net/tti.tamu.edu/documents/0-4642-3.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;report&lt;/a&gt; seems like a good starting point for background info.&lt;/p&gt;&#xA;" OwnerUserId="8440" LastActivityDate="2017-08-17T14:36:00.070" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12104" PostTypeId="2" ParentId="10025" CreationDate="2017-08-18T00:47:26.637" Score="2" Body="&lt;p&gt;The comments suggesting there are lots of ways to remove extreme values but also a great need for caution with precipitation is correct. I am not aware of any good way to test for this from a hydrological perspective, and ~58 mm/day is definitely possible, especially if a region has convective storms. Your best bet for verification is to check nearby gauges and historic storm records if they exist, although there is a very good chance that this is real data and therefore not desirable to remove (even if nearby gauges do not show a similar event that year). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this a single gauge and you want to use it for modeling, you may wish to look at areal reduction factors to scale precipitation from a single gauge to a watershed scale instead of removing the data point.&lt;/p&gt;&#xA;" OwnerUserId="8440" LastEditorUserId="6298" LastEditDate="2018-03-16T04:46:00.660" LastActivityDate="2018-03-16T04:46:00.660" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12105" PostTypeId="2" ParentId="9682" CreationDate="2017-08-18T00:55:14.900" Score="7" Body="&lt;p&gt;My first thought would be to use &lt;a href=&quot;https://en.wikipedia.org/wiki/Manning_formula&quot; rel=&quot;noreferrer&quot;&gt;Manning equation&lt;/a&gt; as an approximation. It does not take into account the effect of a dam burst providing excess water and immediate flooding, although for larger scales (in terms of river reach) this is likely less important. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Detailed hydrologic models may not be the right answer by the way, especially for the tradeoff of the work involved to build them. A detailed forecasting system with a model and real-time data would be the best, but a quick approximation is often a good guess for the work involved. &lt;/p&gt;&#xA;" OwnerUserId="8440" LastActivityDate="2017-08-18T00:55:14.900" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12106" PostTypeId="1" CreationDate="2017-08-18T08:44:17.437" Score="7" ViewCount="3380" Body="&lt;p&gt;I have this notion that at the top, the building will be more likely to shake than at the bottom, where it is grounded.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, how does it work with an earthquake? Who would be more likely to perceive a small earthquake? Someone at the ground floor, or at the 3rd floor? Or 20th floor? Or does it depend on the magnitude of the earthquake?&lt;/p&gt;&#xA;" OwnerUserId="10789" LastEditorUserId="10789" LastEditDate="2017-08-18T14:50:19.713" LastActivityDate="2023-02-09T05:19:40.110" Title="Where are earthquakes felt more: on top of a building or on the ground floor?" Tags="|earthquakes|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="12107" PostTypeId="2" ParentId="12069" CreationDate="2017-08-18T12:01:15.587" Score="1" Body="&lt;p&gt;The thermohaline circulation is what you mean I suppose.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The water cools down while traveling North, causing it to become more dense. Like TomO tells, the water gets saltier due to the loss of salt from the ice mass*. The density of the water will therefore increase, resulting in the sinking of water parcels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*Salt will be released from the sea-ice due to the difference in freezing point of salty water and fresh water. If the temp rises to just below 0*C fresh water will still be frozen, but (dependent on the salinity) the salty ice will melt due to the lower melting point of salty water. Therefore sea-ice will become fresh after a while, and brine is released into the seawater making it more saline. &lt;/p&gt;&#xA;" OwnerUserId="10790" LastActivityDate="2017-08-18T12:01:15.587" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12108" PostTypeId="1" CreationDate="2017-08-19T17:13:34.353" Score="3" ViewCount="527" Body="&lt;p&gt;In this picture you see a fossil of an Ammonite. When you break a slate with a hammer it will fall apart so sometimes you can find a fossil. But is this fossil only there in the slate just at the place where the slate is split apart (so the fossil is actually flat) or is this fossil present in a many layers of the slate which actually gives a three dimensional presentation of the fossil so the place where the slate splits open isn't that important. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://c7.alamy.com/comp/GJMNHA/fossil-slate-texture-GJMNHA.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://c7.alamy.com/comp/GJMNHA/fossil-slate-texture-GJMNHA.jpg&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="5372" LastEditDate="2017-08-19T19:08:41.750" LastActivityDate="2017-08-19T19:08:41.750" Title="Are fossils in slate 3 dimensional or does the slate split open at the weakest point where the flat imprint of the fossil is found?" Tags="|fossils|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12110" PostTypeId="1" CreationDate="2017-08-20T09:40:49.407" Score="1" ViewCount="56" Body="&lt;p&gt;I am looking for data sets for historical global sea level estimates. How would I go about doing this the best way? Are there any publicly available resources for this? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The timespan I am looking at are the following: Preferably from 300 000 - 200 000 years ago to today, or from 15 000 - 10 000 years ago to today. &lt;/p&gt;&#xA;" OwnerUserId="10797" LastActivityDate="2017-08-20T17:02:42.147" Title="Data sets for historical sea level estimates" Tags="|ocean|sea-level|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12111" PostTypeId="2" ParentId="12110" CreationDate="2017-08-20T10:41:01.067" Score="1" Body="&lt;p&gt;There are a number of publicly available proxy records for sea-level/temperature curves, I'd start with &lt;a href=&quot;https://scholar.google.co.nz/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google Scholar&lt;/a&gt; if you want refereed articles but a straight Google search can give you good results if you use the right search terms, like &quot;sea-level over time&quot; gave me some useful &lt;a href=&quot;https://www.google.co.nz/search?q=sea-level+over+time&amp;amp;oq=sea-level+over+time&amp;amp;aqs=chrome..69i57.5407j0j1&amp;amp;sourceid=chrome&amp;amp;ie=UTF-8&quot; rel=&quot;nofollow noreferrer&quot;&gt;results&lt;/a&gt;; I'd recommend the Wikipedia &lt;a href=&quot;https://en.wikipedia.org/wiki/Past_sea_level&quot; rel=&quot;nofollow noreferrer&quot;&gt;result&lt;/a&gt; as most useful to you.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2017-08-20T10:41:01.067" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12112" PostTypeId="1" CreationDate="2017-08-20T10:47:19.250" Score="1" ViewCount="60" Body="&lt;p&gt;I am wondering how accurate such an approximation would be. I wish to take a current height map of the earth (including the ocean floor) and approximate the form of ancient landmasses by changing the sea level height.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suppose this question could be answered by how much the ocean floor changes over time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Timescales: Preferably over the last 200 000 - 300 000 years, but depending on the error of such an approximation, I am willing to settle for the last 10 000 - 15 000 years.&lt;/p&gt;&#xA;" OwnerUserId="10797" LastActivityDate="2017-08-20T23:19:08.953" Title="Approximation of ancient landmasses using current ocean floor data" Tags="|geology|earth-history|sea-level|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12113" PostTypeId="2" ParentId="12110" CreationDate="2017-08-20T13:17:18.613" Score="1" Body="&lt;p&gt;It seems that I have come across usable data myself, I got the data set from PANGAEA (&lt;a href=&quot;https://www.pangaea.de/&quot; rel=&quot;nofollow noreferrer&quot;&gt;www.pangaea.de&lt;/a&gt;), specifically &lt;a href=&quot;https://doi.org/10.1594/PANGAEA.854045&quot; rel=&quot;nofollow noreferrer&quot;&gt;Spratt and Lisiecki (2015, doi: 10.1594/PANGAEA.854045)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It ranges up to 798 ka BP in 1 ka steps with a standard deviation of about 11 - 26 m. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This would be suitable for what I am trying to do, but any other suggestions would still be welcomed.&lt;/p&gt;&#xA;" OwnerUserId="10797" LastEditorUserId="5594" LastEditDate="2017-08-20T17:02:42.147" LastActivityDate="2017-08-20T17:02:42.147" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12114" PostTypeId="2" ParentId="12112" CreationDate="2017-08-20T23:19:08.953" Score="1" Body="&lt;p&gt;over that short a time there would be very little change in the land itself, all you really get is a sea level change due to changes in the ice sheets, continental movement is barely noticeable.&lt;/p&gt;&#xA;&lt;p&gt;such &lt;a href=&quot;https://en.wikipedia.org/wiki/Past_sea_level&quot; rel=&quot;nofollow noreferrer&quot;&gt;measurements&lt;/a&gt; and &lt;a href=&quot;https://www.reddit.com/r/MapPorn/comments/6jm21e/global_coastlines_precatastrophic_sea_level_rise/&quot; rel=&quot;nofollow noreferrer&quot;&gt;maps&lt;/a&gt; already exist.&lt;/p&gt;&#xA;&lt;p&gt;here is the earth 12,000 years ago.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/aIRPI.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aIRPI.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here is the same map with the changes highlighted.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/0SxZr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0SxZr.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;sources for other maps&#xA;&lt;a href=&quot;https://www.fieldmuseum.org/pleistocene-sea-level-maps&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.fieldmuseum.org/pleistocene-sea-level-maps&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://antiquity.ac.uk/projgall/sakellariou334/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://antiquity.ac.uk/projgall/sakellariou334/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Or you can even use &lt;a href=&quot;http://geology.com/sea-level-rise/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this interactive&lt;/a&gt; map, which already does what you want to do, and compare it to past sea level.&lt;/p&gt;&#xA;&lt;p&gt;As for why projecting backwards is easy, you may want to look up the term &amp;quot;continental shelf&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-08-20T23:19:08.953" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12116" PostTypeId="1" AcceptedAnswerId="12117" CreationDate="2017-08-21T04:14:53.110" Score="4" ViewCount="117" Body="&lt;p&gt;It is estimated that only &lt;a href=&quot;https://www.quora.com/How-many-square-miles-of-desert-would-it-take-for-a-solar-farm-to-provide-all-the-electrical-power-for-the-whole-United-States&quot; rel=&quot;nofollow noreferrer&quot;&gt;100 square miles&lt;/a&gt; of solar panels could completely satisfy the United States demand for energy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This got me thinking: A &lt;a href=&quot;http://science.sciencemag.org/content/early/2017/02/08/science.aai7899&quot; rel=&quot;nofollow noreferrer&quot;&gt;cooling film&lt;/a&gt; developed at UC Boulder claims it can eject 93 W/m2 into space under direct sunshine, whereas the sun puts &lt;a href=&quot;https://en.wikipedia.org/wiki/Sunlight&quot; rel=&quot;nofollow noreferrer&quot;&gt;1120 W/m2&lt;/a&gt; onto the earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cooling power of the film is a significant fraction of the total irradiance of the sun. So how many square kilometers of cooling film would be required to return temperatures to (say) 1950 levels assuming current CO2 levels?&lt;/p&gt;&#xA;" OwnerUserId="2696" LastEditorUserId="2696" LastEditDate="2017-08-22T18:53:01.850" LastActivityDate="2017-08-22T18:53:01.850" Title="Cooling film area to undo global warming" Tags="|climate-change|climate-models|geoengineering|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12117" PostTypeId="2" ParentId="12116" CreationDate="2017-08-21T11:38:05.133" Score="4" Body="&lt;p&gt;I will answer the question with some simplifying assumptions that might then provide a coarse guess of the area needed. First lets assume that temperatures have risen $1^{o}C$ and that the cooling film acts as increasing surface albedo effectively reflecting that an additional fraction of sunlight (93/1366) from earth. By following the footsteps of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Idealized_greenhouse_model&quot; rel=&quot;nofollow noreferrer&quot;&gt;idealized greenhouse model&lt;/a&gt; we can derive the surface temperature as:&#xA;$$T_{s} = \bigg(\frac{S_{0}(1 - \alpha_{p})}{4 \sigma (1 - \frac{\epsilon}{2})}\bigg)^{1/4}$$&#xA;Where $T{_s}$ is surface temperature, $S_{0}$ is the solar constant ($1366W/m^ 2$), $\alpha_{p}$ is the planetary albedo, $\sigma$ is the Stefan Boltzmann constant and $\epsilon$ is the emissivity. By approximating the planetary albedo as 0.3 and emissivity as 0.78 we get that the surface temperature of is 288K. We can now set that the surface temperature is one degree smaller and there is an addition to the planetary albedo due to the cooling films. Solving for albedo:&#xA;$$\alpha_{p} = -\bigg(\frac{T_{s}^{4}4\sigma (1-\frac{\epsilon}{2})}{S_{0}} - 1\bigg)$$&#xA;By substituting the values we find that planetary albedo has to be about 0.31, so cooling of one degree has been reached by a 0.01 additional albedo. The ratio of the cooling film absorbency and solar constant $\frac{93}{1366} \approx 0.07$ can be seen as the additional planetary albedo if the cooling film is installed globally. This being seven times the needed change of albedo implies that a seventh of earths surface should be covered.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This doesn't take into account any secondary effects, that all areas of earth aren't equally important, that earths albedo isn't constant, nor is the emissivity, angle of radiation matters, this equation doesn't really take into account greenhouse effect(it just uses values that provides in current state case reasonable numbers), et cetera. More accurate answer would come by running a climate model and tweaking albedo in fixed grid cells.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastEditorUserId="6465" LastEditDate="2017-08-21T12:53:41.423" LastActivityDate="2017-08-21T12:53:41.423" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12118" PostTypeId="1" CreationDate="2017-08-21T21:17:02.473" Score="3" ViewCount="521" Body="&lt;p&gt;I've seen the solar noon formula described as &lt;code&gt;snoon = 720 – 4*longitude – eqtime&lt;/code&gt;. I'm curious if it is equally reliable within a relatively small margin of error (+-60 seconds) to simply get the midpoint between sunrise and sunset, given that data is already calculated and available. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any occasion when solar noon wouldn't be equal time from sunrise and sunset, give or take the aforementioned margin of error? &lt;/p&gt;&#xA;" OwnerUserId="10804" LastActivityDate="2017-08-21T23:38:24.587" Title="Calculating Solar Noon from Sunrise and Sunset" Tags="|earth-rotation|sun|solar-terrestrial-physics|time|" AnswerCount="1" CommentCount="3" ClosedDate="2017-08-22T09:39:25.150" ContentLicense="CC BY-SA 3.0" />
  <row Id="12120" PostTypeId="2" ParentId="12118" CreationDate="2017-08-21T23:38:24.587" Score="0" Body="&lt;p&gt;Received an answer on the astronomy stack. &lt;a href=&quot;https://astronomy.stackexchange.com/questions/22239/getting-solar-noon-from-sunset-and-sunrise/22241#22241&quot;&gt;https://astronomy.stackexchange.com/questions/22239/getting-solar-noon-from-sunset-and-sunrise/22241#22241&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The short of it is that yes, this is reasonably accurate for most geographies, but can vary significantly in polar regions. For most cases, middling the difference of sunrise and sunset is sufficient. &lt;/p&gt;&#xA;" OwnerUserId="10804" LastActivityDate="2017-08-21T23:38:24.587" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12121" PostTypeId="2" ParentId="12028" CreationDate="2017-08-22T00:43:50.730" Score="0" Body="&lt;p&gt;Some atmospheric models (namely the US NCEP HRRR) utilize radar as a source of initial conditions. I don't know the details of exactly how the radar data are assimilated. But Doppler data do provide the model a three-dimensional rendition of moisture and wind patterns on a scale that no other observing instrument is able to resolve, with our current technology.&lt;/p&gt;&#xA;" OwnerUserId="10672" LastActivityDate="2017-08-22T00:43:50.730" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12122" PostTypeId="1" AcceptedAnswerId="12124" CreationDate="2017-08-22T01:29:10.020" Score="10" ViewCount="479" Body="&lt;p&gt;Since there is a total solar eclipse somewhere almost every year, I would have thought it would be included as a standard option in weather forecast models.  However, I've learned that is not really the case.&lt;/p&gt;&#xA;&lt;p&gt;The moon does not normally affect weather much, but during a solar eclipse, there is reduced solar radiation reaching the surface of the Earth.  This causes cooler temperatures and changes in wind speed/direction than would not otherwise be predicted.   The NOAA ESRL HRRR &lt;a href=&quot;https://www.esrl.noaa.gov/gsd/learn/hotitems/2017/eclipse2017-hrrr.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;took the solar eclipse of August 21, 2017 into account&lt;/a&gt; when doing the weather forecast and found &lt;a href=&quot;http://cliffmass.blogspot.com/2017/08/how-will-eclipse-change-us-weather-on.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;cooling of up to 6 degrees Celsius in some places&lt;/a&gt;.  Do any other weather forecast models take solar eclipses into account?  Or, is this the first time?  Why don't weather forecast models normally take solar eclipses into account?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7HqyK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7HqyK.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2021-07-08T19:26:52.683" LastActivityDate="2022-01-26T23:48:37.363" Title="Why don't weather forecast models normally take solar eclipses into account?" Tags="|meteorology|weather-forecasting|solar-terrestrial-physics|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="12124" PostTypeId="2" ParentId="12122" CreationDate="2017-08-22T11:03:41.013" Score="13" Body="&lt;p&gt;Total solar eclipses are rare.  Globally, they only happen every 18 months.  In any given spot, they are much, much rarer, with a recurrence period of many hundreds of years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Solar eclipses are localised in time and space.  Although model resolution may be just about small enough (in time) to resolve the totality, it only has a limited impact.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One could implement solar eclipses in weather forecast models, but there's plenty of more important things to worry about improving.  Operational weather forecast models are complex beasts, so you really want to change things only if it may yield a significant improvement.  The potential improvement of implementing a consideration of solar eclipses is minimal, so it's simply not worth the effort or the risk.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Experimental models are a different category and as you have seen, eclipses have been implemented in those.  But the risks involved are much smaller; nobody really cares if experimental models go totally wrong, but you really don't want to be responsible for breaking the operational weather forecast model.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;You might be interested in this article on &lt;a href=&quot;http://centaur.reading.ac.uk/71326/8/atx135.pdf&quot; rel=&quot;noreferrer&quot;&gt;&lt;em&gt;The weather’s response &#xA;to a solar eclipse&lt;/em&gt;&lt;/a&gt; that  my colleagues wrote.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2017-10-27T10:07:50.483" LastActivityDate="2017-10-27T10:07:50.483" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="12126" PostTypeId="1" AcceptedAnswerId="12128" CreationDate="2017-08-22T13:28:09.430" Score="3" ViewCount="1558" Body="&lt;p&gt;The moon takes about a month to orbit around the Earth. So why we don't have solar eclipse every month?&lt;/p&gt;&#xA;" OwnerUserId="10805" LastActivityDate="2017-08-22T17:45:58.803" Title="why we don't have solar eclipse every month?" Tags="|earth-rotation|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12127" PostTypeId="2" ParentId="12126" CreationDate="2017-08-22T17:43:21.723" Score="2" Body="&lt;p&gt;An eclipse (solar or lunar) happens when the Moon, Sun and Earth align in space and when the Moon intersects exactly with Earth's orbital plane around the Sun. However the Moon's orbit is not exactly the same as Earth's orbital plane (ecliptic) but inclined with a couple degrees. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The locations where the Moon intersects the ecliptic, called nodes, change in time. It happens two times every month but only when these nodes coincide with new or full moon an eclipse will happen.&lt;/p&gt;&#xA;" OwnerUserId="10681" LastActivityDate="2017-08-22T17:43:21.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12128" PostTypeId="2" ParentId="12126" CreationDate="2017-08-22T17:45:58.803" Score="9" Body="&lt;p&gt;The moon's orbit is at a slight angle from the plane of earth's orbit around the sun, so it doesn't always hit the right spot, as described &lt;a href=&quot;https://eclipse2017.nasa.gov/faq&quot; rel=&quot;noreferrer&quot;&gt;on NASA's Total Solar Eclipse 2017 site&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Eclipses only occur if the Moon is located within 0.5 degrees of the&#xA;  plane of the ecliptic, on a line that passes through the center of the&#xA;  Sun and the Earth. The Moon travels along an orbit that is inclined by&#xA;  5 degrees to the ecliptic plane, so there are only two opportunities&#xA;  each month when it passes through the plane of the ecliptic. These&#xA;  points are called the ascending and descending nodes. Eclipses of the&#xA;  Sun only occur if new moon occurs when the Moon is near of one of&#xA;  these nodes. A similar argument explains why lunar eclipses do not&#xA;  occur every full moon at the node opposite the Sun from the Earth.&#xA;  &lt;a href=&quot;https://i.stack.imgur.com/jNQg7.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jNQg7.png&quot; alt=&quot;diagram showing tilt of moon&amp;#39;s orbit&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2017-08-22T17:45:58.803" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12129" PostTypeId="2" ParentId="12122" CreationDate="2017-08-22T18:53:30.883" Score="7" Body="&lt;p&gt;In addition to the rarity, there is also the problem of additional computations. To find out if there is a solar eclipse, you need extra calculations. Since the introduction of additional calculations can slow down the model, especially since radiation is oft quoted as the most expensive physics parameterization, introduction of the astronomy may provide unnecessary calculations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A solar eclipse, while influential, is only influential in the short term, so it is often ignored. Even then, the data assimilation methods can correct for any error after the eclipse (though that would be an interesting project). Plus there is also the complication of clouds, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any forecaster who pays attention to the news knows about the eclipse. Any forecaster who knows the inner workings of models (though many don't) should know that eclipses are ignored in radiation parameterizations. So forecasters should know that it will impact their forecast, but by how much, was uncertain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are things that are ignored in weather models, but we know we ignore them. We ignore them because the are small, difficult to moddel, poorly understood, etc. Such things include aerosols, tropospheric chemistry, tornadoes, heating from lightning, anthropogenic heat flux, drag from buildings.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-08-22T18:53:30.883" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12130" PostTypeId="2" ParentId="12122" CreationDate="2017-08-22T19:51:56.053" Score="7" Body="&lt;p&gt;&lt;a href=&quot;https://www.ecmwf.int/en/faq/does-ecmwf-model-explicitly-factor-solar-eclipses&quot; rel=&quot;nofollow noreferrer&quot;&gt;Doesn't look like the ECMWF does.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Perhaps part of it has to do with the fact the weather changes due to eclipses are usually fairly friendly/tame.  &lt;a href=&quot;https://twitter.com/NWSNewOrleans/status/899711552563052544&quot; rel=&quot;nofollow noreferrer&quot;&gt;This GOES 16 satellite loop&lt;/a&gt; from the southeast US during the eclipse shows a large percentage of the cumulus buildup dissipating as solar input dropped.  And this great meteogram from the &lt;a href=&quot;http://www.mesonet.org/index.php/weather/meteogram/blac/2d&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oklahoma Mesonet&lt;/a&gt; (this site is Blackwell, Oklahoma in northern Oklahoma, though most sites show some impact) shows the slump in solar radiation very well (the bottom plot) and also temperature and wind speed changes during the early afternoon of August 21, 2017 (very slightly left of the middle of the time period of the graph):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/L50wh.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/L50wh.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Typically changes like cooling and slackening winds are not conducive to storms, and as the graph shows, are rebound soon after the eclipse end.&lt;/p&gt;&#xA;&lt;p&gt;It wouldn't seem it's much trouble to include the eclipse... just include a single if statement that checks a date variable holding the next eclipse time.  And then, if it is the eclipse, just modify the insolation variable, probably just by the percentage of the sun's area covered up (which there's probably pretty simple equations to calculate?).  Just seems most haven't really taken the time, perhaps in part because of the event rarity.  Because major operational models are improved during quite regular cycles, including such a rarely-applicable feature like that may end up as more maintenance work than the benefits are worth.&lt;/p&gt;&#xA;&lt;p&gt;There may not be much in the way of dangerous weather created during an eclipse, but that doesn't mean there is no weather.  The &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_eclipse_of_April_8,_2024&quot; rel=&quot;nofollow noreferrer&quot;&gt;next US eclipse in 2024&lt;/a&gt; does offer more potential to be a more weather significant encounter.  Most high-end severe weather in the US occurs during spring as shown with:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Z4bG4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Z4bG4.png&quot; alt=&quot;severe weather by month&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;And there have been a few bouts of severe weather on April 8th, including small bursts in &lt;a href=&quot;http://www.spc.noaa.gov/climo/reports/130408_rpts.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;2013&lt;/a&gt; and &lt;a href=&quot;http://www.spc.noaa.gov/climo/reports/150408_rpts.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;2015&lt;/a&gt;, plus the &lt;a href=&quot;https://en.wikipedia.org/wiki/Tornado_outbreak_of_April_6%E2%80%939,_1998&quot; rel=&quot;nofollow noreferrer&quot;&gt;1998 Alabama F5&lt;/a&gt;.  Radiation in all of those regions will be quite heavily affected by the 2024 eclipse (coverage &amp;gt; 80% anywhere between Alabama and Nebraska).  Would the decrease in energy disrupt severe weather potential later in the day?  An interesting question we'll have to see on!&lt;/p&gt;&#xA;&lt;p&gt;Overall there weren't large impacts during the 2017 eclipse.  As mentioned, temperatures dropped for a little while, and a few clouds dissipated.  But could the regional disruption of the eclipse introduce subtle wind shifts or temperature changes that alter the longterm pattern, more significantly impacting model forecasts later in time during periods of greater weather variability?  An interesting question that would be great to see studied in more detail.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-01-26T23:48:37.363" LastActivityDate="2022-01-26T23:48:37.363" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="12131" PostTypeId="1" AcceptedAnswerId="12134" CreationDate="2017-08-22T20:38:52.163" Score="3" ViewCount="170" Body="&lt;p&gt;Water in the atmosphere is present as vapour, liquid and ice. It is just a small amount of the Earth's total water supply. I'm wondering how long it will take to rain down all the water from the atmosphere and &quot;replace&quot; it with new water by evapotranspiration. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This will give an indication for the maximum accuracy of weather forecasting while atmospheric water plays an essential role in climatological conditions.&lt;/p&gt;&#xA;" OwnerUserId="10681" LastEditorUserId="10681" LastEditDate="2018-10-03T22:33:27.300" LastActivityDate="2018-10-03T22:33:27.300" Title="How long does it take to refresh the entire water supply in the Earth's atmosphere?" Tags="|meteorology|hydrology|weather-forecasting|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12132" PostTypeId="2" ParentId="70" CreationDate="2017-08-23T02:21:21.837" Score="0" Body="&lt;p&gt;A 50% chance of rain means that there is a 50% chance that at least some rain will fall at any given location within the area covered by the weather forecast, within the time period covered by the weather forecast period. It does not mean that it will rain 50% of the time.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-08-23T02:21:21.837" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12133" PostTypeId="1" AcceptedAnswerId="12143" CreationDate="2017-08-23T02:08:38.630" Score="10" ViewCount="842" Body="&lt;p&gt;Recently, a paper was published by &lt;a href=&quot;https://doi.org/10.1016/j.grj.2017.08.001&quot; rel=&quot;nofollow noreferrer&quot;&gt;Abbot and Morahasy (2017)&lt;/a&gt; - see specifically &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S2214242817300426#fig0002&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fig. 2&lt;/a&gt;. The thesis of the paper is to train an artificial neural network (ANN) on the temperature time series for pre-industrial ages. Then do forecasting with the ANN to predict the temperature time series in the 20th century. Because the ANN was trained on pre-industrial time series, then we can say that industrialization is irrelevant to global warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This goes completely contrary to the &lt;a href=&quot;https://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_TS_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC AR5 technical summary&lt;/a&gt;, which shows graphs that global warming is due to anthropogenic causes. See page 74 of the latter report.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So which do you trust and why?&lt;/p&gt;&#xA;" OwnerUserId="2919" OwnerDisplayName="David V" LastEditorUserId="2958" LastEditDate="2019-05-13T03:40:35.680" LastActivityDate="2019-05-13T03:40:35.680" Title="Does this paper, using neural nets, prove industrialization is irrelevant to global warming?" Tags="|climate-change|" AnswerCount="3" CommentCount="15" ContentLicense="CC BY-SA 4.0" />
  <row Id="12134" PostTypeId="2" ParentId="12131" CreationDate="2017-08-23T05:45:01.987" Score="5" Body="&lt;p&gt;The term you are looking for is called &lt;a href=&quot;https://www.merriam-webster.com/dictionary/residence%20time&quot; rel=&quot;nofollow noreferrer&quot;&gt;residence time&lt;/a&gt; or residency time.  &lt;a href=&quot;https://scied.ucar.edu/longcontent/water-cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;This UCAR Science article&lt;/a&gt; suggests it is about 9 days on average.  This should be verifiable by dividing the average &lt;a href=&quot;http://tropic.ssec.wisc.edu/real-time/mimic-tpw/global/main.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;global precipitable water&lt;/a&gt; by the average &lt;a href=&quot;http://www.eldoradocountyweather.com/forecast/world-forecasts/world-day1-rainfall-forecast.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;global daily precipitation&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't see any reason why the residency time of water would offer any hint of weather predictability limits. If the equations to predict evapotranspiration used in forecast models have skill, shouldn't the 9 days not be the limit (and how limiting a factor it is would depend upon how skillful those equations are)? The residence times of vehicles on roadways is probably near/less than an hour, yet we can forecast traffic quite reasonably well in advanced in at least many circumstances (and that's prone to the much more volatile nature of human choice/error)!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Indeed I think the &quot;residence time&quot; of energy in the lower troposphere, if such an idea even has sense, may well be shorter than a day for the Earth given the continual heavy IR absorption and reemission rates in the atmosphere, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_energy_budget&quot; rel=&quot;nofollow noreferrer&quot;&gt;the dominant input being solar energy&lt;/a&gt;. But we can forecast much longer periods than that well.  We have great understanding of insolation into the Earth-air system, and then quite solid skill at predicting its transfer, even with the &lt;a href=&quot;https://rams.atmos.colostate.edu/AT712/proofs/ch5AfterEditing.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;complexity of clouds and other feedbacks&lt;/a&gt;.  So we can outdo such a timescale even if energy passes through the system indeed quite quickly.  Likewise, there seems to be no reason for the 9 days to be a particularly meaningful limit on the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-08-23T15:14:45.650" LastActivityDate="2017-08-23T15:14:45.650" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12135" PostTypeId="1" AcceptedAnswerId="12140" CreationDate="2017-08-23T09:24:43.303" Score="2" ViewCount="1657" Body="&lt;p&gt;I have lots of grd (GrADS) file and I want to convert those data into netCDF file using cdo. The operation needs all the corresponding ctl file and I will have to prepare all these. So, my question is  there any workaround for this using bash, python or R. Here is an example of ctl file:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;*need to change the file name year*_rfp25.grd for each file&#xA;DSET /home/amit/climate_data/rf/year1901_rfp25.grd&#xA;TITLE Gridded rainfall&#xA;UNDEF -999.0&#xA;XDEF  135  LINEAR  66.5 0.25&#xA;YDEF  129  LINEAR  6.5 0.25&#xA;ZDEF   1 linear 1 1 &#xA;* CHANGE TDEF TO 366 FOR LEAP YEARS&#xA;TDEF 365  LINEAR 1jan1901 1DY &#xA;VARS  1&#xA;rf 0 99 GRIDDED RAINFALL&#xA;ENDVARS&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="10815" LastEditorUserId="10815" LastEditDate="2017-08-24T07:24:42.293" LastActivityDate="2020-03-10T18:13:15.270" Title="How to prepare GrADS's .ctl file to convert grd file into .nc file in batch mode?" Tags="|climate|rainfall|netcdf|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12136" PostTypeId="1" AcceptedAnswerId="12137" CreationDate="2017-08-23T12:34:07.640" Score="0" ViewCount="256" Body="&lt;p&gt;&lt;a href=&quot;https://forecast.predictwind.com/atlas/#Wind&quot; rel=&quot;nofollow noreferrer&quot;&gt;PredictWind.com&lt;/a&gt; is able to make wind forecasts on a very precise 8 km scale. For educational reasons I would need the mathematical model used or at least one very similar.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Searching on the internet I did not find much. Do you have any suggestions?&lt;/p&gt;&#xA;" OwnerUserId="8366" LastActivityDate="2017-08-23T16:05:32.130" Title="How to make wind forecast like Predictwind.com? Which mathematical model has been used?" Tags="|wind|weather-forecasting|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12137" PostTypeId="2" ParentId="12136" CreationDate="2017-08-23T16:05:32.130" Score="4" Body="&lt;p&gt;It seems like that particular website is a commercial forecasting website and requires login/registration information, so I will take your word for the output.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The general equation of motion is described by the Navier-Stokes Equations, which is $$\frac{\partial \vec{u}}{\partial t}+(\vec{u} \cdot\nabla)\vec{u}=-\frac{1}{\rho}\nabla P+g\hat{k}+\nu \nabla^2\vec{u}+f\hat{k}\times\vec{u}$$ where $\vec{u}$ is the atmospheric motion vector (wind + vertical motion), $\rho$ is density, $P$ is pressure, $g$ is gravity, $f$ is the coriolis parameter, and $\nu$ is the kinematic viscosity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This very complicated equation currently has no analytic solution (if you have one, you can win $1,000,000 from the Clay Mathematics Institute), but is instead discretized and solved using even heavier mathematics. Additionally, some mathematical tricks are played on the equations to 'simplify' them, but it usually results in other problems.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While 8 km seems like a fine scale, it actually isn't. Smaller phenomenon (called eddies) affect the weather significantly, so research that tries to mimic the effect of those eddies is applied, but there are still problems. Cutting edge research tries to reduce that 8 km (called resolution- think of the resolution of your television) down to tens of meters, but at a significant cost- one that limits the domain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Likely, the data that your website comes from a weather model, which attempts to solve the above equation. Such models could include the ECMWF, GFS, and other global models.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-08-23T16:05:32.130" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12138" PostTypeId="2" ParentId="12133" CreationDate="2017-08-23T16:33:58.317" Score="16" Body="&lt;p&gt;Astrophysicist Ken Rice, author of the &quot;And Then There's Physics&quot; blog on climate science, &lt;a href=&quot;https://andthentheresphysics.wordpress.com/2017/08/22/machine-unlearning/&quot; rel=&quot;noreferrer&quot;&gt;dismisses this particular approach&lt;/a&gt; for, among other things, failing to address the underlying physics of the climate system:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...if you are going to use something like machine learning to make&#xA;  predictions about the future, you do need to be pretty confident that&#xA;  the data that you use to train the machine learning algorithm presents&#xA;  a reasonable representation of the system you’re trying to model. This&#xA;  requires some actual understanding of the system being considered. If&#xA;  you change it by, for example, pumping lots of greenhouse gases into&#xA;  the atmosphere, then the training data will be almost certainly not be&#xA;  appropriate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Climate researcher Gavin Schmidt has &lt;a href=&quot;https://twitter.com/ClimateOfGavin/status/900341454232371200&quot; rel=&quot;noreferrer&quot;&gt;also noted errors in figure 2&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Their time axis is off by ~35 years and magnitude is too large by&#xA;  ~10%. So their '20th C' is actually 1845-1965.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Which means that Abbot and Morahasy's analysis also doesn't include the end of the 20th century and the most recent decades of significant warming.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2017-08-23T16:33:58.317" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12139" PostTypeId="2" ParentId="10536" CreationDate="2017-08-23T18:27:27.880" Score="4" Body="&lt;p&gt;I haven't looked into ERA-Interim wave data a huge amount but I know around 1991 it started to assimilate ocean wave data from satellite altimeters (ERS-1).&#xA;See the first figure here&#xA;&lt;a href=&quot;https://climatedataguide.ucar.edu/climate-data/era-interim&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://climatedataguide.ucar.edu/climate-data/era-interim&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I remember Jean-Raymond Bidlot who runs WAM at ECWMF showing me so experiments with and without the assimilation into the wave. I think the Hs differed by ~1m in large events so not insignificant.&lt;/p&gt;&#xA;" OwnerUserId="10819" LastActivityDate="2017-08-23T18:27:27.880" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12140" PostTypeId="2" ParentId="12135" CreationDate="2017-08-23T21:14:54.867" Score="2" Body="&lt;p&gt;After some trial n error I figured it out using the following shell script&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;#!/bin/bash&#xA;&#xA;day_number () {&#xA;year=$1&#xA;leap=&quot;false&quot;&#xA;&#xA;if [ $((year % 4)) -ne 0 ] ; then&#xA;   :&#xA;elif [ $((year % 400)) -eq 0 ] ; then&#xA;     leap=&quot;true&quot;&#xA;elif [ $((year % 100)) -eq 0 ] ; then&#xA;   : &#xA;else&#xA;&#xA;   leap=&quot;true&quot;&#xA;fi&#xA;if [ &quot;$leap&quot; == &quot;true&quot; ];&#xA;then&#xA;   echo 366&#xA;else&#xA;   echo 365&#xA; fi&#xA;}&#xA;&#xA;for j in {1901..2015};&#xA;do&#xA;days=$(day_number j)&#xA;echo &quot;DSET /home/amit/climate_data/rf/year${j}_rfp25.grd&#xA;TITLE Gridded rainfall&#xA;UNDEF -999.0&#xA;XDEF  135  LINEAR  66.5 0.25&#xA;YDEF  129  LINEAR  6.5 0.25&#xA;ZDEF   1 linear 1 1 &#xA;* CHANGE TDEF TO 366 FOR LEAP YEARS&#xA;TDEF ${days}  LINEAR 1jan${j} 1DY &#xA;VARS  1&#xA;rf 0 99 GRIDDED RAINFALL&#xA;ENDVARS&quot;&amp;gt;year${j}_rfp25.ctl&#xA;done&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="10815" LastActivityDate="2017-08-23T21:14:54.867" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12141" PostTypeId="2" ParentId="12133" CreationDate="2017-08-23T23:19:19.590" Score="2" Body="&lt;p&gt;Machine learning may sound like some magical phrase, that is able to solve every problem, but it's definetly not.&#xA;I don't have the paper available right now, but what I can say in general right now is the following:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What machine learning is good at, is finding patterns in any number of dimensions. If you apply machine learning to a time series (a 1-D data space) that fluctuates boringly around a mean average, as it did in pre-industrial times, then the only thing it will be able to predict is the continuation of this trend.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, taking the ANN to predict data outside of it's training range is equivalent to just taking an extremely-high order polynomial through all your datapoints and then extrapolating into the future. The former is a classical example of data manipulation, also strongly advised against in every introductory physics or statistics class.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The last paragraph shall, without rigorous proof, just show that using ANN to predict trends in any kind of data, is not very smart and reveals a fundamental misunderstanding of how ANN work.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2017-08-23T23:19:19.590" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12143" PostTypeId="2" ParentId="12133" CreationDate="2017-08-24T08:44:35.227" Score="19" Body="&lt;p&gt;The paper is deeply flawed from both the climate science and machine learning perspectives.  The most obvious being the most eye-catching claim that equilibrium climate sensitivity is approximately 0.6C, which if true would overturn our understanding of the climate system.  However the paper doesn't actually explain how this figure of 0.6C is obtained from a &quot;largest deviation&quot; of 0.2C, it is basically just a hand-wave.  Also the largest deviation is not 0.2, this is the largest &lt;em&gt;average&lt;/em&gt; (mean absolute) deviation seen in the proxies, and you can have a mean absolute deviation without there being a trend that you could relate to increased GHG concentrations and hence estimate ECS.  More importantly, this would give an estimate of &lt;em&gt;transient&lt;/em&gt; climate sensitivity, not &lt;em&gt;equilibrium&lt;/em&gt; climate sensitivity, and you can't reliably estimate ECS (which is global) from regional or sub-regional proxy records.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Approaches such as the one taken in this paper, which seek to see how much of the data can be attributed to &quot;climate cycles&quot; with the remainder being taken as the anthropogenic component are inherently biased towards low estimates of ECS.  This is because of omitted variable bias; because the anthropogenic forcing signals are not included in the model, if the net effect of independent changes in the forcings is correlated with a sinusoidal component, they will be wrongly attributed to these climate cycles, when in fact they are produced by the forcings.  Models like this can only be used to estimate lower bounds on ECS, likewise if you make a model using the forcings as inputs and treat the residual as being &quot;natural variability&quot; it will tend to over-estimate ECS, giving an upper bound estimate.  The  Abbot and Morahasy paper cites a similar &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0304380014000404&quot; rel=&quot;noreferrer&quot;&gt;paper&lt;/a&gt; by Loehle, but sadly does not also cite the &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0304380014004876&quot; rel=&quot;noreferrer&quot;&gt;comment paper&lt;/a&gt; (of which I was the lead author, note the corregendum).  This is poor scholarship, and sadly  Abbot and Morahasy have gone on to make many of the same basic mistakes (but with a more complicated model), which is a shame.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rather than using the original datasets (many of which are freely available) the authors chose to digitise images of the datasets instead.  This seems somewhat bizarre, and Gavin Schmidt &lt;a href=&quot;https://twitter.com/ClimateOfGavin/status/900366059072389121&quot; rel=&quot;noreferrer&quot;&gt;points out via twitter&lt;/a&gt; that in at least one case the dataset has not been scaled or aligned correctly (andends at 1965, and so does not include the recent warming where anthropogenic contributions are most evident).  It also transpires that Figures 5 and 9 are identical.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The paper says &lt;em&gt;&quot;However, superior fitting to the temperature proxies are obtained by using the sine wave components and composite as input data. This was established by comparing the spectral analysis composite method versus the ANN method for the training periods.&quot;&lt;/em&gt;.   Evaluating performance on the training data is a classic error in the use of machine learning that people used to make all the time in the late 1980s and 90s, but is rarely seen today.  If you have two nested models (one can be implemented as a special case of the other) of different complexities, then the more complex model will always have a lower training set error, if only because it has more capacity to memorize the random noise in the data, but that doesn't mean it is the more accurate model.  For that you need out-of-sample comparisons, which are absent from the paper.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is no handling of uncertainty in the model (for instance the periods of the cyclic components are not known exactly, cycles with slightly different periodicities will explain the observations almost as well), and likewise there will be uncertainty in the parameters of the neural net, but none of this is propagated through to give the uncertainty in the estimate of ECS.  As seen in the comment on the Loehle paper, this can be substantial.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Table 13 seems to suggest that paleoclimate studies give lower ECS estimates than GCMs, which suggests a rather selective view of the paleoclimate studies, which generally indicate high ECS IIRC.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The study also has problems with too many degrees of researcher freedom (e.g. how was the particular subset of proxies chosen?) and there is a lot of (automated) exploration of model architectures and feature selection, which is often a recipe for over-fitting in model selection.  It is also not clear why the observation should be a &lt;em&gt;non-linear&lt;/em&gt; function of the cyclic variables (especially given that the cycles were obtained from the data by linear analysis).&lt;/p&gt;&#xA;" OwnerUserId="624" LastActivityDate="2017-08-24T08:44:35.227" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12145" PostTypeId="2" ParentId="12067" CreationDate="2017-08-24T10:12:17.947" Score="2" Body="&lt;p&gt;The length scale associated with molecular viscosity in the ocean is much smaller than typical oceanographic length scales. Zero relative velocity will apply over perhaps a few millimeters. Beyond this, exchanges of momentum are actually achieved by turbulence, not by molecular viscosity. This is the reason why Ekman theory is built on the principle of conservation of momentum (action-reaction between ocean and atmosphere) and effectively discards the condition that relative velocity at the interface should be zero. &lt;/p&gt;&#xA;" OwnerUserId="10821" LastActivityDate="2017-08-24T10:12:17.947" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12146" PostTypeId="2" ParentId="12069" CreationDate="2017-08-24T12:26:26.017" Score="5" Body="&lt;p&gt;Complementary to the points about salinity emphasised by TomO and S Verhoef, one more point to emphasise is the role of deep ocean convection. You may have in mind this picture of water sinking because it gets heavy, which is not quite wrong, but you get a more accurate picture if you see that the water column down to about 3000 meter deep is convectively mixing (mainly in winter) in localised areas of the  Greenland, Iceland, Norwegian and Labrador seas. Convection is what you get when dense water lies above lighter fluid, which is as unstable as an egg on its head. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The consequence of this mixing is twofold. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;First it shapes the hydrological structure of the deep ocean and determines its organisation into distinct water masses (e.g.: &lt;a href=&quot;http://www.soes.soton.ac.uk/teaching/courses/oa631/plot_20w.jpg&quot; rel=&quot;noreferrer&quot;&gt;http://www.soes.soton.ac.uk/teaching/courses/oa631/plot_20w.jpg&lt;/a&gt; ) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second it induces a strong cooling of the ocean water masses. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Together these effects control the strength of the meridional overturning cell. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If your are after an advanced and authoritative review on this, see &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2015RG000493/full&quot; rel=&quot;noreferrer&quot;&gt;http://onlinelibrary.wiley.com/doi/10.1002/2015RG000493/full&lt;/a&gt;, which is open access. &lt;/p&gt;&#xA;" OwnerUserId="10821" LastActivityDate="2017-08-24T12:26:26.017" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12148" PostTypeId="2" ParentId="3100" CreationDate="2017-08-25T11:44:27.850" Score="1" Body="&lt;p&gt;When describing the development of a mountain range, a clear distinction must be made between the origin of the rocks that are found in the mountain range, and the development of the current topographic high that defines the mountain range. The Great Dividing Range, as the topographic high that we see today, was developed from the Cretaceous into the Tertiary. Some of the rocks found in the Great Dividing Range have been part of earlier mountain ranges that were eroded away before the Permian.&lt;/p&gt;&#xA;" OwnerUserId="10828" LastActivityDate="2017-08-25T11:44:27.850" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12149" PostTypeId="1" AcceptedAnswerId="19654" CreationDate="2017-08-25T12:54:10.943" Score="7" ViewCount="378" Body="&lt;p&gt;I would like to know if a specific seismometer can measure 1 micron/sec velocity. I have a few specs from the datasheet but I'm not a seismologist and am trying to figure out how to relate the specs to one another.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Velocity output band: 30s (0.03Hz) to 100 Hz&#xA;Output Sensitivity: 2400 V/m/s&#xA;Peak/Full scale output: Differential: +- 20V &#xA;Sensor dynamic range: 137 dB @ 5 Hz&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Thanks in advance!&lt;/p&gt;&#xA;" OwnerUserId="10830" LastActivityDate="2020-04-30T08:47:43.673" Title="How can I calculate the sensitivity of a seismometer?" Tags="|geophysics|seismology|instrumentation|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12150" PostTypeId="1" CreationDate="2017-08-25T13:08:16.420" Score="4" ViewCount="74" Body="&lt;p&gt;Emphasis here is &lt;em&gt;did&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm trying to find a &lt;strong&gt;source that will inform me about which locations in the United States &lt;em&gt;actually&lt;/em&gt; had their view of the eclipse on Aug 21, 2017 obscured by clouds&lt;/strong&gt;. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;I'd preferably like a visual source or a compiled list of cloud covers, though compiled anecdotal accounts would be interesting, too. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I'd found a number of sources for predicting/forecasting/modeling potential cloud cover &lt;em&gt;before&lt;/em&gt; the eclipse, which I used to keep my eclipse traveling/viewing plans fluid until the morning of Aug 21. However, I can't seem to find a source that shows me what the cloud cover &lt;em&gt;actually&lt;/em&gt; looked like across the path of totality (and elsewhere). Essentially, I want to know how many of my dozens of changing planned destinations would or would not have worked out. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;With so many planned destinations that changed due to changing forecasts, perhaps it would be best to have a cloud cover &lt;em&gt;map&lt;/em&gt; (vs. lists or personal accounts).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I'm most interested in knowing &lt;strong&gt;cloud cover during actual &lt;em&gt;totality&lt;/em&gt;&lt;/strong&gt; &lt;em&gt;across the path of totality&lt;/em&gt;. If this is too much to ask, then I'd narrow that search to the Southeastern US (NC, SC, TN, GA).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where can I find such data?&lt;/p&gt;&#xA;" OwnerUserId="7536" LastEditorUserId="7536" LastEditDate="2017-08-26T22:39:52.403" LastActivityDate="2017-08-26T22:39:52.403" Title="Where did clouds obscure the American eclipse of August 2017?" Tags="|meteorology|clouds|sun|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12151" PostTypeId="1" CreationDate="2017-08-26T00:35:53.997" Score="1" ViewCount="165" Body="&lt;p&gt;I am using the MATLAB script BLIMP (Ferguson and Margrave, 1995) to invert SH-wave data for shear-impedance. Is this inversion scheme a linear or non-linear process? There are certainly non-linear calculations occurring (i.e. integration and exponentiation), but I am unsure if that automatically qualifies it as non-linear.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For whatever answer you have, please provide some reference for me to track down.&lt;/p&gt;&#xA;" OwnerUserId="8447" LastEditorUserId="28050" LastEditDate="2018-04-05T00:26:11.833" LastActivityDate="2018-04-05T00:26:11.833" Title="Linear vs nonlinear seismic inversion" Tags="|seismic|inversion|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12152" PostTypeId="1" CreationDate="2017-08-26T02:05:14.577" Score="6" ViewCount="487" Body="&lt;p&gt;I did a google image search for a world map of offshore oil. Surprisingly I found virtually nothing. I had to search country by country for such maps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I noticed most if not all were located very near the country's shore, on the continental shelf. These are fairly shallow seafloors, not even going below 1 km deep.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I guess this is because, it's easiest to explore (and drill) in the shallow regions first. But what I want to know, is there good reason to believe the very deep ocean also has oilfields.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So here is my question: &lt;strong&gt;Given our current understanding of geological history, is it likely that the oceans have decent oilfields located underneath the very deep seafloor?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Decent oilfield&quot; would be something like 10+ million barrels of oil without more sulfur than a Heavy Grade of Crude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We have good bathymetric data of most oceanfloor, e.g., the underwater mountain-range in the mid-Atlantic, and the superdeep trenches following the Mariana Islands. I'm hoping that just by looking at the shape, we can make a good prediction where oil is located.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My only hint is a few very deep regions in the Gulf of Mexico, like &lt;a href=&quot;http://www.subseaiq.com/data/PrintProject.aspx?project_id=124&amp;amp;AspxAutoDetectCookieSupport=1&quot; rel=&quot;noreferrer&quot;&gt;this field&lt;/a&gt; that's 2.7 km below the sea. I am not aware of any other deep offshore platforms. I noticed the &lt;a href=&quot;http://energy-cg.com/GOM/Depth/GOM_depth_3D_view_Jul15_Image1x1_EnergyConsutlingGroup_web.png&quot; rel=&quot;noreferrer&quot;&gt;Gulf of Mexico&lt;/a&gt; has a fairly...what's the word here...bubbly shape in the deep parts.&lt;/p&gt;&#xA;" OwnerUserId="2733" LastActivityDate="2017-08-26T10:23:26.923" Title="Are there probably decent oil fields located in the middle of the ocean?" Tags="|ocean|mineralogy|petroleum|fossil-fuel|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12153" PostTypeId="1" AcceptedAnswerId="12154" CreationDate="2017-08-26T02:21:08.997" Score="4" ViewCount="800" Body="&lt;p&gt;Watching the news for the US hurricane Harvey and they say it will make landfall soon. But what part of the hurricane are they referring to?&lt;/p&gt;&#xA;" OwnerUserId="10833" LastEditorUserId="10833" LastEditDate="2017-08-26T04:27:05.523" LastActivityDate="2017-08-26T13:44:08.783" Title="What part of a hurricane determines if it makes landfall?" Tags="|meteorology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12154" PostTypeId="2" ParentId="12153" CreationDate="2017-08-26T05:34:33.800" Score="4" Body="&lt;p&gt;Hurricanes make &quot;landfall&quot; when the center of the eye moves over land. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the &lt;a href=&quot;http://www.nhc.noaa.gov/aboutgloss.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA National Hurricane Center glossary&lt;/a&gt;: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Landfall:&#xA;  The intersection of the surface center of a tropical cyclone with a coastline.Because the strongest winds in a tropical cyclone are not located precisely at the center, it is possible for a cyclone's strongest winds to be experienced over land even if landfall does not occur. Similarly, it is possible for a tropical cyclone to make landfall and have its strongest winds remain over the water. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Below is an example image showing when landfall occurred for Hurricane Harvey:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rZQw7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rZQw7.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="6298" LastEditDate="2017-08-26T13:44:08.783" LastActivityDate="2017-08-26T13:44:08.783" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12155" PostTypeId="2" ParentId="12152" CreationDate="2017-08-26T10:23:26.923" Score="9" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Are there probably decent oil fields located in the middle of the ocean?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;tl;dr: no.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hydrocarbon deposits form by thermal maturation (i.e. slow and mild heating) of buried organic matter (i.e. dead things) in sedimentary rocks. This is exactly why you find hydrocarbons...&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;very near the country's shore, on the continental shelf&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;...because that's exactly where you find sedimentary rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In contrast, the deep ocean basins are igneous rocks (mostly basalts) overlain by thin marine sediments with very little organic material. Whatever organic material is there, it never has the chance for maturation. It's either very cold, or gets heated in subduction and is lost forever in the deep mantle.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-08-26T10:23:26.923" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12157" PostTypeId="1" CreationDate="2017-08-27T03:32:11.447" Score="7" ViewCount="298" Body="&lt;p&gt;This comes from &lt;a href=&quot;https://earthscience.stackexchange.com/questions/12152/are-there-probably-decent-oil-fields-located-in-the-middle-of-the-ocean&quot;&gt;a related question&lt;/a&gt; about predicting oil (or not) in the deep sea, not just the continental shelf. Apparently the deep seafloor is igneous, which lowers its chances of holding oilfields.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yet the Gulf of Mexico, the deep part, does have at least &lt;a href=&quot;http://www.subseaiq.com/data/PrintProject.aspx?project_id=124&amp;amp;AspxAutoDetectCookieSupport=1&quot; rel=&quot;noreferrer&quot;&gt;one oilfield&lt;/a&gt; being exploited. This leads me to ask if there's anything unique about the Gulf and Caribbean Sea relative to the &quot;normal&quot; deep seafloor, whatever that is.&lt;/p&gt;&#xA;" OwnerUserId="2733" LastActivityDate="2019-03-19T16:51:24.823" Title="Is the seafloor of the Gulf of Mexico and Caribbean Sea mostly sedimentary rock?" Tags="|ocean|oceanography|sea-floor|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12159" PostTypeId="1" AcceptedAnswerId="12162" CreationDate="2017-08-27T13:50:38.863" Score="100" ViewCount="21487" Body="&lt;p&gt;&lt;a href=&quot;http://www.foxnews.com/us/2017/08/27/harvey-causes-catastrophic-flooding-in-houston-shuts-down-airport.html&quot; rel=&quot;noreferrer&quot;&gt;Hurricane Harvey dumped more that 20 inches (500 mm) of rain&lt;/a&gt; over a large region, with 40+ (&gt;1000 mm) in some spots... and much more expected.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How is that possible?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does the atmosphere really hold that much water?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or is it getting repeatedly evaporated from the ocean and dropped onto the land by the circular winds, implying an enormous evaporation rate while over water?&lt;/p&gt;&#xA;" OwnerUserId="10841" LastEditorUserId="6" LastEditDate="2017-08-30T09:53:08.280" LastActivityDate="2018-05-26T17:02:12.280" Title="How can a storm drop 40 inches (1 metre) of rain?" Tags="|rainfall|tropical-cyclone|" AnswerCount="6" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12160" PostTypeId="2" ParentId="12159" CreationDate="2017-08-27T15:13:44.523" Score="13" Body="&lt;p&gt;Harvey is almost stationary and is rotating new gulf moisture up the &quot;dirty&quot; side (east of the center). I am outside the main path and have 10+ inches (250 mm) in 30 hours (emptied the rain gauge twice). It has been reported that affected areas have exceeded the &quot;500 year&quot; rainfall level. I guess they need a 1000 year level. The atmosphere is pretty big and does hold that much water.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastEditorUserId="725" LastEditDate="2018-01-28T11:25:16.637" LastActivityDate="2018-01-28T11:25:16.637" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12161" PostTypeId="2" ParentId="12159" CreationDate="2017-08-27T17:09:46.317" Score="25" Body="&lt;p&gt;I invite correction if I missed any details, the column of air above you, at any one time, at 100% humidity can hold maybe 3-6 inches (75-150 mm) of water depending on temperature and it's likey to rain only a percentage of that, not all of it.   If air remained stationary, which, of-course it doesn't, then we'd get much less downpours.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The hurricane is continuously spiraling in new wet air with water picked up from the gulf.   It might rain 2-4 inches (50–100 mm) per hour, which over 10 or more hours can give you 30-40 inches (750-1000 mm).   As it rains, the air loses moisture, so the area that gets 30-40 inches (750-1000 mm) smaller in size than the Hurricane.   It's the specific area, land just past the ocean or gulf, to the East or North-East of the eye where the saturated bands of rain come in from over the ocean or Gulf that gets hit the hardest.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This chart isn't updated, it's a forecast from a day ago, but it gives an idea of the localized high rain fall amounts.  The region that gets the 20 plus inches (500+ mm) of rain is smaller than the Hurricane.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lhSXi.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lhSXim.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The wind spirals around the eye much faster than the Hurricane itself moves, and it gets saturated to 100% humidity and in a sense, over 100% humidity as it can carry water droplets, as it spirals over the warm waters of the Gulf of Mexico.  When it hit's land, the rain continues but the humidity begins to drop, so the rain falls hardest, shortly after landfall and where the rain bands come from over the ocean, Usually, in the East Coast of the US, this is East or Northeast of the eye.   (The dirty side, as blacksmith calls it).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vhFgE.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vhFgE.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Air can't hold 40 inches (1000 mm) of rain.  No where close, but air blowing over a body of water can supply steady rainfall because the air blowing over the gulf is continuously picking up water.   It's new, 100% humidity/saturated and super-saturated air that hits land continuously, raining hard, until the storm passes.    &lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="20" LastEditDate="2017-09-03T03:01:06.987" LastActivityDate="2017-09-03T03:01:06.987" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12162" PostTypeId="2" ParentId="12159" CreationDate="2017-08-27T17:28:06.247" Score="134" Body="&lt;p&gt;You were right to question whether the atmosphere really held that much water.  It comes nowhere close!  We use &lt;a href=&quot;https://en.wikipedia.org/wiki/Precipitable_water&quot; rel=&quot;noreferrer&quot;&gt;precipitable water&lt;/a&gt; to track this, which is the measure of all moisture in the entire column of air in the troposphere.  We can get good widespread estimates from remote observations.  &lt;a href=&quot;http://www.ospo.noaa.gov/Products/bTPW/TPW_Animation.html?product=CONUS_TPW&quot; rel=&quot;noreferrer&quot;&gt;This animation&lt;/a&gt; shows current amounts of precipitable water levels across the US from satellite.  Here is a still from this afternoon (Sunday, August 27) during the Harvey event:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fhH55.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fhH55.png&quot; alt=&quot;PWat082717&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;75 mm is less than 3 inches.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We also get &lt;a href=&quot;https://www.britannica.com/topic/in-situ-measurement&quot; rel=&quot;noreferrer&quot;&gt;in-situ&lt;/a&gt; exact measurements worldwide from twice daily radiosonde balloon launches.  Unfortunately none are located right near the locations receiving excess rainfall.  But you can check US sites of current precipitable water measurements any time by going to &lt;a href=&quot;http://www.spc.noaa.gov/exper/soundings/&quot; rel=&quot;noreferrer&quot;&gt;SPC's sounding page&lt;/a&gt; and looking for the PW value in the left side of the bottom table.  &lt;a href=&quot;http://www.spc.noaa.gov/exper/soundingclimo/&quot; rel=&quot;noreferrer&quot;&gt;SPC also maintains a climatology page for precipitable water and other values&lt;/a&gt;.  You can see there that 3 inches (76 mm) of moisture in the sounding is extremely rare, and no US site has ever had 4 inches (102 mm) of precipitable water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the answer is also not truly found in evaporation rates.  The conditions in strong hurricanes do greatly enhance evaporation rates due to the high wind speeds and warmer waters.  Measurements are actually a bit difficult to come by in such extreme conditions, with challenges in isolating evaporation effects from spray as well as in getting the instruments positioned into such environments (new field campaign: who wants to take the research ship out into the category 5 hurricane!?!).  As &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2006JD008303/full&quot; rel=&quot;noreferrer&quot;&gt;this 2007 study by Trenberth et al.&lt;/a&gt; noted:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We are unaware of reliable estimates of evaporation in hurricanes, and published measurements do not exist in winds above about 20 m s−1 although some progress has been made in the Coupled Boundary Layer Air-Sea Transfer Experiment (CBLAST) &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, in that study model analyses suggested that evaporation rates in the core of hurricanes are likely no more than 1-2 inches (25–50 mm) per day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How is that possible?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's quite important to notice that heavy rainfall - well over 5 inches (125 mm) - can actually fall in as little as a couple hours almost anywhere, such as in &lt;a href=&quot;https://www.weather.gov/oax/event_archive_20150507&quot; rel=&quot;noreferrer&quot;&gt;this 2015 flood event in Nebraska&lt;/a&gt;.  How can that be?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The secret lies in the nature of even the weakest storm: even as a storm is just beginning to form, it begins to draw in air from surrounding areas.  This is NOAA's diagram of a typical developing thunderstorm cell:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/06I0j.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/06I0j.jpg&quot; alt=&quot;developing&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see the curve at the arrows near the bottom, indicating inflow of surrounding air into the storm.  This inflow turns a thunderstorm into more of an engine, processing a continuing stream of incoming air, removing its moisture.  In a single cell thunderstorms in an environment without background winds, the &quot;waste&quot; air will eventually pile up and choke off the influx.  But even in such circumstances, a few inches of rain may fall.  That isn't by using up all of the moisture from the cloud's environment, but instead by using just a portion of the moisture from the reservoir in and around the cloud.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If some upper level winds exist to help exhaust the &quot;spent&quot; air, storm systems can persist for even longer periods of time.  For example, the Midwestern United States commonly sees long-duration late summer heavy rainfall initiated along stationary boundaries in which inflow lacks direct access to significant warm water bodies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Larger systems that dump huge amount of precipitation over greater areas must pull in a more consistent, stronger inflow of warm, moist air from greater distance.  Examples of this happening include the &lt;a href=&quot;https://www.accuweather.com/en/weather-news/what-is-a-pineapple-express/38881189&quot; rel=&quot;noreferrer&quot;&gt;Pineapple Express&lt;/a&gt; for rainfall in California/the southwest US, the &lt;a href=&quot;http://www.spc.noaa.gov/publications/evans/kumjian.pdf&quot; rel=&quot;noreferrer&quot;&gt;low-level jet&lt;/a&gt; for spring and summer squall lines in the Plains, &lt;a href=&quot;http://www.meteo.co.in/monsoon1.cfm&quot; rel=&quot;noreferrer&quot;&gt;onshore winds during&lt;/a&gt; the Indian monsoon, and air from off the &lt;a href=&quot;https://www.e-education.psu.edu/earth107/node/1055&quot; rel=&quot;noreferrer&quot;&gt;Gulf Stream&lt;/a&gt; in Nor'easters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In all these regional large precipitation events moist air gathered from a great surface area flows into a smaller region.  As the air approaches, it is lifted by the low pressure and its associated features, condenses, and finally falls as rain (or snow).  This process is often termed &quot;moisture convergence&quot;.  The Storm Prediction Center also &lt;a href=&quot;http://www.spc.noaa.gov/exper/mesoanalysis/&quot; rel=&quot;noreferrer&quot;&gt;offers plots&lt;/a&gt; of localized deep moisture convergence [choose a region, then look under the upper air menu].  The convergence contours, shown in red, really show the piling up of humidity that is causing the heavy rainfall in Harvey:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jA6uk.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jA6uk.jpg&quot; alt=&quot;Harvey Convergence&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But perhaps to visualize the scale involved in creating a catastrophic largescale flood such as Harvey, this plot, created from a base image from &lt;a href=&quot;http://www.pivotalweather.com&quot; rel=&quot;noreferrer&quot;&gt;pivotalweather.com&lt;/a&gt;, best shows the conditions around the storm (from the GFS model):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7Ykb7.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7Ykb7.png&quot; alt=&quot;harvey diagram&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically the atmosphere of the entire Gulf (and beyond) is being pumped into the southeast Texas area.  So although the air can only hold a couple inches (some 50 mm) of water, and evaporation rates are typically only a fraction of an inch (several mm) per day... bringing that together from such a large source region, and focusing it down into one small area... can lead to these awful extreme deluges. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;hr&gt;&#xA;Addendum: It should also be highlighted that the NHC adds in their &lt;a href=&quot;https://www.nhc.noaa.gov/data/tcr/AL092017_Harvey.pdf&quot; rel=&quot;noreferrer&quot;&gt;report on Harvey&lt;/a&gt; that rising motion was also enhanced by a front which had stalled in the area.  Air being advected in by Harvey's flow would naturally rise over that layer of cooler air when moving inland (a process called isentropic lift), which proves particularly efficient in condensing out the (abundant) moisture en masse into rainfall.  Most substantial regional floods require similar existence of a significant broad lifting mechanisms overlaid with such a relentless inflow of warm, moist air.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-05-26T17:02:12.280" LastActivityDate="2018-05-26T17:02:12.280" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="12163" PostTypeId="1" AcceptedAnswerId="12165" CreationDate="2017-08-27T18:37:14.627" Score="0" ViewCount="231" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ppWbN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ppWbN.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What behavior of this hurricane would lead to advisories for the west coast and even parts of Canada and Alaska, when the hurricane is in the South?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have little experience in meteorology or any of the earth sciences really, so I am interested in how this would affect the weather or other conditions far away from where the hurricane is severe.&lt;/p&gt;&#xA;" OwnerUserId="10844" LastActivityDate="2017-08-27T18:55:53.177" Title="Why would Google's map of areas affected by Hurricane Harvey have advisories for the west coast and other far away areas?" Tags="|meteorology|tropical-cyclone|extreme-weather|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12164" PostTypeId="1" AcceptedAnswerId="12335" CreationDate="2017-08-27T18:53:03.420" Score="4" ViewCount="570" Body="&lt;p&gt;The numbers bandied about have been 3.6 m (12 feet) and even 4.6 m (15 feet), but something told me that was unlikely.  As a guy who could &quot;almost&quot; slam dunk a basketball, the idea of a 3 m (10 feet) surge (height of a basketball goal) is formidable.  4-5 m (12-15 feet) is terrifying.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I have not found any statements on how high the storm surged ocean-wise.  I've seen plenty of homes wiped off of their foundations from wind, but if you look carefully homes right next to them are still quite intact.  My guess is the max &quot;surge&quot; was less than 1 m (&amp;lt;2 feet). Does anyone know this or where to find it?&lt;/p&gt;&#xA;" OwnerUserId="10845" LastEditorUserId="111" LastEditDate="2017-09-21T11:40:55.553" LastActivityDate="2017-09-21T11:40:55.553" Title="What was the storm surge height from Hurricane Harvey?" Tags="|tropical-cyclone|tides|storms|flooding|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12165" PostTypeId="2" ParentId="12163" CreationDate="2017-08-27T18:55:53.177" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/X8NKB.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/X8NKB.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;It seems like there is more than just a hurricane going on. According to the &lt;a href=&quot;http://weather.gov&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Weather Service&lt;/a&gt; there are excessive heat advisories, gale warnings, etc. &lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-08-27T18:55:53.177" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12166" PostTypeId="1" CreationDate="2017-08-27T19:50:08.527" Score="1" ViewCount="105" Body="&lt;p&gt;Where would somebody find the highest concentrations of Iron on or near Earth's surface?&lt;/p&gt;&#xA;" OwnerUserId="10846" LastEditorUserId="2536" LastEditDate="2017-08-27T21:22:05.643" LastActivityDate="2017-08-27T21:22:05.643" Title="Which places in Earth's crust have the highest concentrations of Iron?" Tags="|crust|iron|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12168" PostTypeId="1" AcceptedAnswerId="12169" CreationDate="2017-08-28T15:06:14.493" Score="3" ViewCount="3968" Body="&lt;p&gt;We were in Legoland in Windsor (SE England) recently, and towards the end of the day, we noticed what looked like a ring of cloud in the sky. It was quite large (hard to say as being up in the sky we didn't have a reference point to measure it by). It gently changed shape as it rose, presumably due to the wind, until it dissipated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9lKKj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9lKKj.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyone able to explain what it was? Thanks&lt;/p&gt;&#xA;" OwnerUserId="10858" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T09:14:48.063" LastActivityDate="2023-04-08T15:25:51.273" Title="What is this ring of cloud?" Tags="|clouds|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="12169" PostTypeId="2" ParentId="12168" CreationDate="2017-08-28T18:32:01.773" Score="9" Body="&lt;h1&gt;It might be a smoke ring, but it's not known for sure.&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;There have been several sightings of similar objects over the past few years.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;A ring was seen &lt;strong&gt;&lt;a href=&quot;http://www.huffingtonpost.co.uk/2014/04/15/black-ring-of-leamington-spa-_n_5150871.html&quot; rel=&quot;noreferrer&quot;&gt;in Leamington Spa&lt;/a&gt; in 2014&lt;/strong&gt;. Theories about its origin included a group of insects, as well as an ordinary smokestack (perhaps the ring stayed in one piece for an inordinately long time). Eventually, it was discovered that &lt;a href=&quot;http://www.bbc.com/news/blogs-magazine-monitor-27037579&quot; rel=&quot;noreferrer&quot;&gt;it was the result of a fireworks test&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LaDTa.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LaDTa.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;A similar object was seen &lt;strong&gt;&lt;a href=&quot;http://www.huffingtonpost.co.uk/2015/04/07/black-ring-kazakhstan_n_7015928.html&quot; rel=&quot;noreferrer&quot;&gt;in Kazakhstan&lt;/a&gt; in 2015&lt;/strong&gt;. Video of it received quite a lot of publicity, and many people labeled it a UFO. In that instance, the object was ~100 meters in diameter and ~200 to 1000 meters in altitude. The smokestack hypothesis was once again brought forth. &lt;a href=&quot;http://www.dailymail.co.uk/news/article-3027519/Holy-smoke-Mysterious-100m-wide-black-ring-filmed-floating-clear-skies-Kazakhstan.html&quot; rel=&quot;noreferrer&quot;&gt;Another article&lt;/a&gt; mentions that some people attributed the ring to &lt;a href=&quot;https://en.wikipedia.org/wiki/Microburst&quot; rel=&quot;noreferrer&quot;&gt;thermal microbursts&lt;/a&gt; (see also &lt;a href=&quot;https://ll.mit.edu/publications/journal/pdf/vol01_no1/1.1.4.microbursts.pdf&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;); however, microbursts move down, and your ring rose up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/m074n.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/m074n.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;An irregular ring was observed &lt;strong&gt;&lt;a href=&quot;https://www.thesun.co.uk/news/4008168/mystery-black-rings-in-sky-around-world-pictures/&quot; rel=&quot;noreferrer&quot;&gt;in Birkenshaw&lt;/a&gt; earlier this year (2017)&lt;/strong&gt;. This case is notable because the ring in this case was distinctly non-planar; it was warped, just like yours. It may have been &lt;a href=&quot;http://www.mirror.co.uk/news/uk-news/explained-mysterious-black-smoke-ring-10795042&quot; rel=&quot;noreferrer&quot;&gt;from an explosion from a military reenactment&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VpfHG.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VpfHG.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This article notes that another ring was seen in Windsor, right near where you were:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/i7Asr.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/i7Asr.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;There are many more examples besides these.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some notable features about these rings:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;They are &quot;hazy&quot; or smeared in parts. In your case, you can see a dark section on the left; the Leamington Spa ring has a smear on the upper left and the Kazakhstan ring has a smear on the right.&lt;/li&gt;&#xA;&lt;li&gt;The rings are pretty circular. This may be an indication that they are artificial.&lt;/li&gt;&#xA;&lt;li&gt;Most are flat, but some (like yours) exhibit some warping, which could indeed be cause by wind.&lt;/li&gt;&#xA;&lt;li&gt;The rings are darker than the clouds around them, as we can see in all cases but that Kazakhstan ring.&lt;/li&gt;&#xA;&lt;li&gt;They were sighted near places where explosions were taking place on the ground (&lt;a href=&quot;http://www.express.co.uk/news/weird/679422/ALIEN-PORTAL-Sinister-black-ring-UFO-terrifies-families-at-Disneyland&quot; rel=&quot;noreferrer&quot;&gt;a similar ring in California&lt;/a&gt; was seen at Disneyland).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I'm willing to rule out microbursts in your case because the ring rose. Insects are still a possibility, and perhaps the smears are due to individual bugs flying outside the pattern, but I have yet to see any behavioral study to explain it. This leaves the theory that these rings are from smokestacks or certain detonations, which is well-supported. Not all of the rings were seen near heavy industrial areas, mind you, but that doesn't rule out that hypothesis in those cases. Smaller smoke machines or explosions could still be the culprits, possibly at a ride in Legoland itself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most similar type of cloud I can think of is a &lt;a href=&quot;https://en.wikipedia.org/wiki/Lenticular_cloud&quot; rel=&quot;noreferrer&quot;&gt;lenticular cloud&lt;/a&gt;, a common explanation for UFO sightings:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EKQDN.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EKQDN.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;br&gt;&#xA;&lt;sup&gt;&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Lenticular_Cloud_over_Harold%27s_Cross_Dublin_Ireland_30-6-15.jpg&quot; rel=&quot;noreferrer&quot;&gt;Image&lt;/a&gt; courtesy of Wikipedia user Omnisource5 under &lt;a href=&quot;https://creativecommons.org/licenses/by-sa/4.0/deed.en&quot; rel=&quot;noreferrer&quot;&gt;the Creative Commons Attribution-Share Alike 4.0 International license&lt;/a&gt;.&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, lenticular clouds aren't ring-shaped, but disk-shaped, and they usually aren't quite that flat. Therefore, I'd rule a lenticular cloud out here.&lt;/p&gt;&#xA;" OwnerUserId="1399" LastEditorUserId="1399" LastEditDate="2017-08-28T18:43:24.747" LastActivityDate="2017-08-28T18:43:24.747" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12170" PostTypeId="2" ParentId="2113" CreationDate="2017-08-29T02:19:30.960" Score="0" Body="&lt;p&gt;It is likely true for the very heaviest rains, which exceed one inch per minute and last no more than a few minutes, that sustainable rainfall rate diminishes with increasing time that the rain lasts. New supplies of water vapor cannot be entrained into a cloud in such a short time, so such extreme rainfall rates can be sustained only until the water supply within the cloud is exhausted and the cloud rains itself out. But moderately heavy rains can be sustained for very long times. For example, rainfall rates averaging, say, 1 to 2 inches per hour (24 to 48 inches per day) can be sustained in the eye wall of a hurricane, perhaps even indefinitely, if the hurricane remains over the tropical ocean. The hurricane's inspiraling winds can continually replenish the water vapor supply fast enough to replace such a loss by rainfall in the eye wall. Of course, once a hurricane moves over colder, higher-latitude water or over land, the rate of replenishment is diminished and hence so is the sustainable rainfall rate.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-08-29T02:19:30.960" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12172" PostTypeId="2" ParentId="5063" CreationDate="2017-08-29T12:15:50.573" Score="1" Body="&lt;p&gt;Higher amplitude waves, on water, are caused by larger disturbances and longer durations of energy input, in the form of wind, than smaller ones. Quite simply in order to build a big ocean wave you need to put in a lot of acceleration of surface waters over an extended period of time. So it's not just that the wave itself is travelling that much faster, the whole surface that the wave is moving on is itself moving in the same direction as the wave on the surface. The larger amplitude of the waves is in fact partly due to them going faster rather than the other way around.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NB: This doesn't apply with Tsunami waves as those are full column disruptions involving the water column from seabed to wave crest.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2017-08-29T12:15:50.573" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12173" PostTypeId="1" CreationDate="2017-08-29T14:54:17.090" Score="0" ViewCount="84" Body="&lt;p&gt;I have information about temperature, pressure, normal and shear stresses, viscosity, conductivity, density, heat capacity and adiabatic heating for a particular area of mantle in the form of 2D matrices. I want to show phase relation for this region of mantle. Is there an equation (group of equations) which relates phase relation for mantle with these properties?&lt;/p&gt;&#xA;" OwnerUserId="5557" LastActivityDate="2019-03-06T21:13:16.267" Title="Phase relation for mantle?" Tags="|rocks|mineralogy|geodynamics|mantle|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12175" PostTypeId="2" ParentId="12159" CreationDate="2017-08-29T19:42:24.603" Score="6" Body="&lt;p&gt;The atmosphere can &quot;hold&quot; only maximum 75mm worth of precipitation at any given locality, this is true.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this particular hurricane Harvey was a very slowly moving structure. The vortex would carry the warm water-saturated masses from Gulf of Mexico, which essentially collided with colder air from the North, generating rainfall. It is the continuous supply of moisture from warmer saturated area that made the rain nearly continuous at some particular locations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the hurricane structure would sit over one area and not dissipate over time, then the evaporation from the Gulf could sustain the moisture level in the air, and the amount of total rainfall (in limited area) could be even higher. The source evaporation rate doesn't need to be unusual, because a relatively large area of gulf/ocean feeds moist air to a relatively much smaller area of rainfall under this particular type of air circulation pattern.&lt;/p&gt;&#xA;" OwnerUserId="6584" LastEditorUserId="514" LastEditDate="2017-08-30T17:18:07.227" LastActivityDate="2017-08-30T17:18:07.227" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12176" PostTypeId="2" ParentId="12159" CreationDate="2017-08-29T21:36:29.717" Score="5" Body="&lt;p&gt;The precipitable water vapor content of the air never exceeds about 3 inches even in the most humid tropical maritime air masses, and in most maritime tropical air masses is typically closer to 2 inches. But Harvey is not limited to the water vapor content in its own region of the atmosphere. Its counterclockwise INspiraling winds (note the emphasis on IN) continually bring in new water vapor being evaporated from the Gulf of Mexico. The counterclockwise INspiraling winds concentrate the water vapor supply from a region much larger than Harvey itself into Harvey's central region. Thus these counterclockwise INspiraling winds act as a funnel, concentrating what would have been a 2 or 3 inch rain over a large area to a 50 inch rain over a much smaller area.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-08-29T21:36:29.717" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12179" PostTypeId="1" CreationDate="2017-08-30T03:34:40.720" Score="0" ViewCount="934" Body="&lt;p&gt;I was recently reminded of when, while with some friends 20some years ago, we happened to look up and see a circle of what seemed to be light (in the sky of course).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The circle was &quot;empty&quot; (only the circumference was lit up), parallel to the ground, and it seemed rather large from our point of view. I can only speculate on its altitude, in that it may have seemed closer to earth than space, but not that close.&#xA;In particular, it looked fantastically precise, as if drawn with a compass.&#xA;It did not look like a projection or a bat signal of sorts. I cannot reliably say if there were any clouds, if pressed I would venture a no.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This happened in southern Europe (near Rome).&#xA;We have lived here about 40 years, and do not recall anything similar before or since.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What might we have been looking at (googling &quot;circle of light in the sky&quot; is kind of a lost cause) ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am ashamed to admit that our reaction as Young Dynamic People was &quot;Maaaan&quot; and off to the pub, so we didn't hang around to see if it would fade or what else.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tagging is tentative, suggestions are welcome.&lt;/p&gt;&#xA;" OwnerUserId="10810" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T11:54:31.677" LastActivityDate="2021-05-17T18:39:50.233" Title="Identifying circle of light in night sky" Tags="|astronomy|light|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="12180" PostTypeId="1" AcceptedAnswerId="12234" CreationDate="2017-08-30T08:04:28.717" Score="3" ViewCount="135" Body="&lt;p&gt;I am trying to understand Deterministic Seismic Hazard analysis for which I believe seismic waves corresponding to a seismic sources (such as faults) are required to prepare the Gutenberg Richter curve and select an appropriate earthquake corresponding to a particular return period. However I do not know from where I can obtain the seismic data?&lt;/p&gt;&#xA;" OwnerUserId="8363" LastActivityDate="2017-10-07T18:53:47.180" Title="Earthquake database for fault" Tags="|earthquakes|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12182" PostTypeId="1" AcceptedAnswerId="12184" CreationDate="2017-08-30T13:06:52.170" Score="0" ViewCount="62" Body="&lt;p&gt;NCEP's Twentieth Century Reanalysis (V2) provides daily variables from 1871/01/01 to 2012/12/31. Monolayer &lt;strong&gt;analysis variables&lt;/strong&gt; are made available in a regular grid and &lt;strong&gt;forecast variables&lt;/strong&gt; in a gaussian grid. This distinction is made very clear in their list on &lt;a href=&quot;https://www.esrl.noaa.gov/psd/data/gridded/data.20thC_ReanV2.monolevel.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;their webpage&lt;/a&gt;, although I think the grid is not the main problem here, but the terms in bold.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Daily precipitation rate, for example, is a forecast variable. This makes you think weather you may use forecast and analysis interchangeably. What are the main differences? Any pros or cons? Are all of these still considered &lt;strong&gt;reanalysis&lt;/strong&gt;? Any assumputions I need to make?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This question came up as a consequence of the discussion held &lt;a href=&quot;https://earthscience.stackexchange.com/questions/10727/single-layer-water-content-variables&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you in advance.&lt;/p&gt;&#xA;" OwnerUserId="8396" LastActivityDate="2017-08-30T18:17:29.763" Title="Difference between NCEP's 20th Century daily Forecast and Analysis variables" Tags="|meteorology|climate-models|open-data|climatology|reanalysis|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12184" PostTypeId="2" ParentId="12182" CreationDate="2017-08-30T18:17:29.763" Score="3" Body="&lt;p&gt;Some variables in reanalyses have to be forecast and cannot be assimilated to allow the model to converse mass, momentum and energy. Precipitation is a good example. The model will assimilate observations which give information about moisture (someone who knows more about assimilation may want to chirp in here). This will be used in the analysis (e.g. 00z) and is forecast forward. Daily precipitation is therefore given as the accumulation of precipitation from 00z analysis -&gt; 12z forecast and the 12z analysis -&gt; 24z forecast.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a hierarchy of precipitation datasets each with pros and cons:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Gauge data is often considered the best but it very patchy (not to mentions instrument issues). You can use &lt;a href=&quot;https://en.wikipedia.org/wiki/Kriging&quot; rel=&quot;nofollow noreferrer&quot;&gt;kriging&lt;/a&gt; to make spatial maps. This &lt;a href=&quot;https://www.hydrol-earth-syst-sci-discuss.net/hess-2017-508/&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt; may be of interest.&lt;/li&gt;&#xA;&lt;li&gt;Satellite datasets such as &lt;a href=&quot;https://www.esrl.noaa.gov/psd/data/gridded/data.gpcp.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;GPCP&lt;/a&gt; and &lt;a href=&quot;https://pmm.nasa.gov/trmm&quot; rel=&quot;nofollow noreferrer&quot;&gt;TRMM&lt;/a&gt; give better spatial information but subject to issues over land, for example (I think). The are also subject to trackiness (only get data underneath/near the satellite).&lt;/li&gt;&#xA;&lt;li&gt;Reanalyses can provide spatial and temporal homogeneity but it is a model and 'all models are wrong, but some are useful'.  &lt;/li&gt;&#xA;&lt;li&gt;Datasets are emerging combining both gauge, satellite and reanalyses such as in this &lt;a href=&quot;https://www.hydrol-earth-syst-sci.net/21/589/2017/&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="10819" LastActivityDate="2017-08-30T18:17:29.763" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12186" PostTypeId="1" CreationDate="2017-08-30T21:44:32.313" Score="6" ViewCount="168" Body="&lt;p&gt;In &lt;A HREF=&quot;https://en.wikipedia.org/wiki/Paleoclimatology&quot; rel=&quot;nofollow noreferrer&quot;&gt;paleoclimateology&lt;/A&gt; graphs of both temperature and atmospheric composition versus time are common. Where can I find a reconstruction of sea surface pressure versus time?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have found one paper that reconstructs &lt;A HREF=&quot;http://www.nature.com/ngeo/journal/v9/n6/full/ngeo2713.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;atmospheric pressure about 2.7 billion years ago&lt;/A&gt; that claims pressure then was about half of what it is today based on the distribution of bubble sizes in lava, and links to a paper with similar conclusions based on fossilized rain drop (spatter) sizes.&lt;/p&gt;&#xA;" OwnerUserId="10914" LastEditorUserId="10914" LastEditDate="2017-09-01T17:12:16.373" LastActivityDate="2017-09-03T08:37:24.493" Title="Is there a reconstruction of paleoclimate sea level air pressure?" Tags="|atmosphere|atmosphere-modelling|paleoclimatology|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12188" PostTypeId="1" AcceptedAnswerId="12203" CreationDate="2017-08-31T05:34:47.283" Score="4" ViewCount="2286" Body="&lt;p&gt;I've noticed that many places with large populations tend to be prime zones for natural disaster.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Examples:&lt;/em&gt; Silicon Valley = earthquakes, Houston = hurricanes and floods, Japan = tsunamis and earthquakes, Santa Maria = volcano, Vesuvius = volcano, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This doesn't seem like a coincidence, especially given that people would naturally want to stay &lt;em&gt;away&lt;/em&gt; from disaster-prone sites. Clearly there must be a benefit to living in such places.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My &lt;strong&gt;guess&lt;/strong&gt; has always been that it probably goes something like this:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;Active fault zone → mountains &amp;amp; volcanoes → rain &amp;amp; &lt;strong&gt;water&lt;/strong&gt; → fertile soil &amp;amp; wildlife → &lt;strong&gt;food&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Or maybe like this:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;Storms/monsoons → rain &amp;amp; &lt;strong&gt;water&lt;/strong&gt; → fertile soil &amp;amp; wildlife → &lt;strong&gt;food&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But I really have no idea, and this has been a question I've had for a long time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this accurate? Is there more than meets the eye? Is it maybe partly a coincidence?&lt;br&gt;&#xA;Explanations would be greatly appreciated, since all I have right now is just a guess.&lt;/p&gt;&#xA;" OwnerUserId="379" LastActivityDate="2020-03-24T07:51:18.643" Title="Why do human populations concentrate near fault lines, volcanoes, etc.?" Tags="|climate|volcanology|earthquakes|natural-disasters|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12189" PostTypeId="1" CreationDate="2017-08-31T10:35:17.457" Score="4" ViewCount="301" Body="&lt;p&gt;For example the Northern Africa is getting closer to Europe, where the depth of the sea is lower than in south African coast&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could it be that the water's pressure pushes the continent from where the sea is deeper?&lt;/p&gt;&#xA;" OwnerUserId="10923" LastEditorUserId="6298" LastEditDate="2017-08-31T14:59:09.963" LastActivityDate="2017-09-01T20:16:02.943" Title="Could water pressure at the coast be the cause of continental drift?" Tags="|plate-tectonics|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="12190" PostTypeId="1" CreationDate="2017-08-31T16:22:44.773" Score="3" ViewCount="931" Body="&lt;p&gt;I have 3 arrays, for longitude, latitude and temperature (so the observations are scattered in space). I want to apply interpolation on these data, but also extrapolation. I 've written the code beow, but I get an error about memory. Each of the three arrays has about 700 points.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason that I want to extrapolate is because i want to cover all of the region of the map.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the part of my code, which is about what I described:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;m = Basemap(projection='merc',llcrnrlat=34,urcrnrlat=42,\&#xA;        llcrnrlon=19,urcrnrlon=35,lat_ts=20,resolution='h')&#xA;&#xA;xi = np.arange(19,35,0.01)&#xA;&#xA;yi = np.arange(34,42,0.01)&#xA;&#xA;xi,yi = np.meshgrid(xi,yi)&#xA;&#xA;lon = np.asarray(lon)&#xA;&#xA;lat = np.asarray(lat)&#xA;&#xA;temperature = np.asarray(temperature)&#xA;&#xA;rbf = scipy.interpolate.Rbf(lon, lat, temperature, function='gaussian', smooth=0.)&#xA;&#xA;zi = rbf(xi, yi)&#xA;&#xA;x,y = m(xi, yi)&#xA;&#xA;zi=np.array(zi)&#xA;&#xA;mdata=maskoceans(xi,yi,zi,resolution='f',grid=1.25)&#xA;&#xA;m.drawcoastlines()&#xA;&#xA;m.drawcountries()&#xA;&#xA;m.drawmapboundary(fill_color=&quot;#cce6ff&quot;)&#xA;&#xA;sc = m.contourf(x,y,mdata, np.arange(-15.0,40.01,1),cmap=jet,extend=&quot;both&quot;)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Does anyone have any ideas about the interpolation methods that I should use and how I could make it work?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've already used griddata, which works fine, but it is just for interpolation, so the new matrix is limited and it doesn't cover the whole area. I've also read that rbf doesn't work for more than 20 points, but is there any other method for large datasets?&lt;/p&gt;&#xA;" OwnerUserId="10670" LastEditorUserId="6467" LastEditDate="2017-09-01T07:00:18.050" LastActivityDate="2017-09-01T07:00:18.050" Title="Interpolation and extrapolation of unstructured data in python: memory error" Tags="|meteorology|temperature|python|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12191" PostTypeId="1" CreationDate="2017-08-31T16:50:11.637" Score="3" ViewCount="575" Body="&lt;p&gt;Wondering if there's data of what could be the average life span of an hurricane considering global warming as factor.&lt;/p&gt;&#xA;" OwnerUserId="10925" LastActivityDate="2017-08-31T16:50:11.637" Title="Average life span of a hurricane" Tags="|weather-forecasting|extreme-weather|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12192" PostTypeId="1" CreationDate="2017-08-31T17:41:56.283" Score="3" ViewCount="195" Body="&lt;p&gt;One thing that has stood out from our past hurricanes in central Florida and also from watching those around the country is the real large propensity for folks to board up windows.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But it has also seemed, at least with our limited experience (with fairly weak hurricanes overall), that there was rather minimal breakage of windows left unprotected.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Certainly it's a complicated relationship, and things like debris quantity and exposure vary greatly.  But nonetheless, I wonder if anyone has taken any basic statistics.  Even those could greatly help in focusing preparation messages; saying &quot;you're about X times more likely to have a window break at XXX mph versus XXX mph&quot; would be quite useful, as would &quot;only X% of windows break during a category 1 hurricane&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Certainly the stronger the wind, the more vital that windows endure, as any breakage could well undermine the structure at stronger wind speeds.  But it'd just be great to be able to offer more informed statements if they exist!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2017-08-31T17:41:56.283" Title="What statistics do we have regarding the probability of window breakage by wind speed?" Tags="|tropical-cyclone|statistics|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="12193" PostTypeId="1" CreationDate="2017-08-31T19:19:46.880" Score="1" ViewCount="148" Body="&lt;p&gt;Various sources agree land cover changes impact the attenuation of stormwater. E.g. forest areas generally slow the rainfall-runoff response and moderate it, reducing peaks in hydrographs, as compared to urban areas. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is there a way stormwater attenuation can be quantified, by field measurements (eg. observed streamflow) or model outputs?&lt;/strong&gt; If so, what are some examples of how this can be done? The reason to quantify attenuation would be to compare differences in attenuation between different basins or between different conditions within a basin.&lt;/p&gt;&#xA;" OwnerUserId="4789" LastActivityDate="2017-09-01T19:03:28.893" Title="Are there ways stormwater attenuation can be quantified for comparison between different systems or conditions?" Tags="|hydrology|measurements|storms|runoff|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12194" PostTypeId="2" ParentId="12189" CreationDate="2017-08-31T23:31:51.367" Score="4" Body="&lt;p&gt;Water pressure on both sides of the continent makes sure that all horizontal forces cancel out. So water pressure will not move a continent to the left or right because the pressure on the other side exerts the same force just in the opposite direction (assuming equal water depth). But the water pressure puts the continent under compression and will push the two sides of an ocean apart (putting the oceanic plate underneath under tension). In total, however, these forces are far too small to have any impact on plate tectonics.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2017-08-31T23:31:51.367" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12196" PostTypeId="2" ParentId="12093" CreationDate="2017-09-01T08:40:47.080" Score="5" Body="&lt;p&gt;One can account for greenhouse gas effect for Earth's temperature in simple energy balance model in following manner.&lt;/p&gt;&#xA;&lt;p&gt;Assume that fraction &lt;span class=&quot;math-container&quot;&gt;$f$&lt;/span&gt; of longwave radiation emitted by Earth's surface is captured by green house gases in the atmosphere. Suppose Earth's surface temperature is &lt;span class=&quot;math-container&quot;&gt;$T_e$&lt;/span&gt; and temperature of the atmosphere is &lt;span class=&quot;math-container&quot;&gt;$T_a$&lt;/span&gt;. The energy received from Sun should balance as follows&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\pi {r_e}^2 F_0 (1 - A) = 4 \pi r_e^2 (1-f) \sigma {T_e}^4 + 4 \pi r_e^2  \sigma {T_a}^4 $$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$F_0$&lt;/span&gt; is solar constant (Energy received from sun per unit area per unit time), A is Earth's albedo, &lt;span class=&quot;math-container&quot;&gt;$\sigma$&lt;/span&gt; is StephenBotlzmann constant and &lt;span class=&quot;math-container&quot;&gt;$r_e$&lt;/span&gt; is Earth's radius.&lt;/p&gt;&#xA;&lt;p&gt;Since the black body radiation are isotropic, 50% of radiation emitted by atmosphere travels toward Earth's surface and remaining 50% of radiation travels toward the space. Also, assuming that atmosphere receives all of its energy from Earth's surface through longwave radiation, it gives following energy balance equation&#xA;&lt;span class=&quot;math-container&quot;&gt;$$f \sigma {T_e}^4 = 2  \sigma {T_a}^4. $$&lt;/span&gt;&#xA;which leads to&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ T_a = T_e\left(\frac{f}{2}\right)^{\frac{1}{4}}  $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Nearly 80% of the radiation emitted from Earth's surface is absorbed by greenhouse gases (including water vapour) and clouds. Substituting value of &lt;span class=&quot;math-container&quot;&gt;$f$&lt;/span&gt; 0.8 and solving it for &lt;span class=&quot;math-container&quot;&gt;$T_e$&lt;/span&gt; will get you the answer you are looking for.&lt;/p&gt;&#xA;&lt;h2&gt;Reference&lt;/h2&gt;&#xA;&lt;p&gt;Chapter 7 The Greeenhouse Effect in Introduction to Atmospheric Chemistry by Daniel Jacob&#xA;&lt;a href=&quot;http://acmg.seas.harvard.edu/people/faculty/djj/book/bookchap7.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://acmg.seas.harvard.edu/people/faculty/djj/book/bookchap7.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="10780" LastEditorUserId="2470" LastEditDate="2022-07-17T23:59:56.703" LastActivityDate="2022-07-17T23:59:56.703" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="12199" PostTypeId="2" ParentId="12193" CreationDate="2017-09-01T19:03:28.893" Score="1" Body="&lt;p&gt;A typical ratio calculated to quantify this type of response, especially at larger scales (such as for land use changes) is the &lt;strong&gt;runoff ratio&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$R = Q/ P$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $R$ is the runoff ratio [mm/mm or dimensionless], $Q$ is the annual flow volume [mm], and $P$ is the annual precipitation [mm]. The runoff ratio is usually calculated for a given data period (multiple years of data) or on an annual basis. It is tricky to calculate for individual events since the antecedent conditions play a large role, but on an annual basis this would be a decent metric to compare different basins or the same basin in time. This is assuming you have a number of years of data to calculate the ratio from.&lt;/p&gt;&#xA;" OwnerUserId="8440" LastActivityDate="2017-09-01T19:03:28.893" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="12200" PostTypeId="2" ParentId="12189" CreationDate="2017-09-01T20:16:02.943" Score="2" Body="&lt;p&gt;This would not explain many observed movements.  For instance, the part of North America west of the San Andreas fault is moving northwards WRT the land east of the fault.  Similarly, the Indian subcontinent was once an isolated land mass.  Water pressure would thus have acted equally on all sides, and it wouldn't have moved to collide with Asia and so raise the Himalayas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further, the value of a theory is in its explanatory power.  Conventional plate tectonics explains a lot of things: the pattern of sea floor spreading seen around mid-ocean ridges, the geology of rocks at subduction zones, the location of volcanos, and more.  The water pressure theory addresses nothing except the movement.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2017-09-01T20:16:02.943" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12203" PostTypeId="2" ParentId="12188" CreationDate="2017-09-02T05:11:28.017" Score="14" Body="&lt;p&gt;You're asking&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Why do human populations concentrate near fault lines, volcanoes, etc.?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But the real question is &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Do human populations concentrate near fault lines, volcanoes,&#xA;  etc.?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And the answer is not necessarily positive. Let's look at where earthquakes are:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GqgOw.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GqgOw.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and active volcanism:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DWSgB.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DWSgB.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both maps are from &lt;a href=&quot;https://www.volcanodiscovery.com/volcano-map.html&quot; rel=&quot;noreferrer&quot;&gt;Volcano Discovery&lt;/a&gt;. Here's a population density map:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2TyT2.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2TyT2.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Couldn't find the source for that, but a similar interactive website is this one: &lt;a href=&quot;http://luminocity3d.org/WorldPopDen/&quot; rel=&quot;noreferrer&quot;&gt;http://luminocity3d.org/WorldPopDen/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finding a 1:1 correlation between these two natural hazards and population density is very hard. Most of the World's population reside in India, China, Europe, central Africa, and east North America. All of these areas not particularly hazardous in terms of fault lines and volcanoes. Other volcano-abundant areas are only populated if they're around the tropics (Mexico, Indonesia).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So no, the answer is that human population do not concentrate near fault lines or volcanoes more than they concentrate elsewhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On a local scale, however, &lt;a href=&quot;http://volcanology.geol.ucsb.edu/soil.htm&quot; rel=&quot;noreferrer&quot;&gt;volcanic soils&lt;/a&gt; are &lt;a href=&quot;https://prezi.com/iu7x2cylj6gw/soil-fertility-in-volcanoes/&quot; rel=&quot;noreferrer&quot;&gt;fertile&lt;/a&gt; and an excellent place to grow food. This might attract people to volcanoes, because food is vital for life and a maybe-yes-maybe-no threat of a volcano (particularly if it's not obviously active) is a lower priority thing for most people. Also see the interesting story of &lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Pinatubo&quot; rel=&quot;noreferrer&quot;&gt;Pinatubo&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sometimes, people did not know there was a hazard. &lt;a href=&quot;https://en.wikipedia.org/wiki/Par%C3%ADcutin&quot; rel=&quot;noreferrer&quot;&gt;Parícutin&lt;/a&gt; is a volcano in Mexico that just appeared out of nowhere in 1943. Christchurch, NZ, was considered a low earthquake risk zone until it was &lt;a href=&quot;https://en.wikipedia.org/wiki/Christchurch#History&quot; rel=&quot;noreferrer&quot;&gt;struck by several quakes&lt;/a&gt; in the recent years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is some truth to your two guesses that storms provide water for food and mountains lead to rivers which also provide water for food. But it's not a direct relationship. Think of the Nile river, which gets the water from mountains far south but feeds millions in Egypt. There are many more other examples.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-09-02T05:11:28.017" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12204" PostTypeId="1" CreationDate="2017-09-02T09:43:35.767" Score="0" ViewCount="2099" Body="&lt;p&gt;A cloud has relative humidity of 100% or more. Is it correct to say that the mixing ratio of a cloud is undefined? My reasoning is that dry air in a cloud is negligible therefore $w = \frac{x g}{ 0 kg}$&lt;/p&gt;&#xA;" OwnerUserId="8219" LastEditorUserId="6465" LastEditDate="2017-09-04T07:59:56.823" LastActivityDate="2017-09-04T07:59:56.823" Title="What is the mixing ratio of a cloud?" Tags="|meteorology|clouds|humidity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12205" PostTypeId="2" ParentId="12159" CreationDate="2017-09-02T13:23:40.137" Score="3" Body="&lt;p&gt;Harvey has been using a &lt;a href=&quot;https://en.wikipedia.org/wiki/Rainband&quot; rel=&quot;nofollow noreferrer&quot;&gt;rainband&lt;/a&gt; to get water in from the Gulf of Mexico.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Think of the rainband as a pipe, it is piping water from the gulf to the core, and this pipe has a leaking problem, so the water gets dumped on Austin on it's path to the center. &lt;/p&gt;&#xA;" OwnerUserId="10939" LastEditorUserId="6031" LastEditDate="2017-09-03T05:50:17.957" LastActivityDate="2017-09-03T05:50:17.957" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12206" PostTypeId="2" ParentId="7929" CreationDate="2017-09-02T13:31:11.920" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Cutting the $CO_2$ in half would yield about 5.9.&quot; &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(A valid approach because we expect reversibility in chemistry and physics.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[pH of 5.9 for 200 ppm $CO_2$]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Atmospheric $CO_2$ of 200 would be about that of the last glacial maximum. So most of the difference between pure water at pH 7 and 5.9 would seem to be other gases dissolved in air. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Side note: A drop to much below 200 ppm $CO_2$ would extinguish all life on Earth except those that live at geothermal vents at the bottom of the ocean, because they do not use $CO_2$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a linear relationship is assumed, then if there were 800 ppm of $CO_2$, rain water would have a pH of 5.0.  Though, if we assume the log relationship for concentrations that userLTK mentions in the comments, it would be a pH of 5.3.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bouttes, N., D. Paillard, D. M. Roche, V. Brovkin, and L. Bopp (2011), Last Glacial Maximum CO2 and δ13C successfully reconciled, Geophys. Res. Lett., 38, L02705, doi:10.1029/2010GL044499.&lt;/p&gt;&#xA;" OwnerUserId="10940" LastEditorUserId="543" LastEditDate="2017-09-17T03:19:00.153" LastActivityDate="2017-09-17T03:19:00.153" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12207" PostTypeId="1" CreationDate="2017-09-02T14:32:18.033" Score="9" ViewCount="1406" Body="&lt;p&gt;From what I understand, global warming will make growing food a lot harder in areas like the American Midwest because temperatures will become too high for most crops. At the same time, Arctic (and Antarctic) regions will heat up and permafrost will melt. Would areas like Alaska, Siberia, and northern Canada then become suitable for large-scale agriculture? And if so, would this be enough to make up for the lost production in warmer areas? Or are there other factors in those areas that would make farming impractical?&lt;/p&gt;&#xA;" OwnerUserId="10941" LastActivityDate="2020-10-31T19:49:45.383" Title="Will global warming lead to agriculture in the Arctic?" Tags="|climate-change|agriculture|arctic|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12209" PostTypeId="2" ParentId="7295" CreationDate="2017-09-02T19:04:55.717" Score="2" Body="&lt;p&gt;TL;DR: When reporting precipitation types, we still have to manually look out the window.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;TL;SR: You do not mention how the information is gathered, so I will go over the different ways.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first and most obvious one is the air temperature.  If the air temperature is above freezing then you have rain, below you have snow.  Until recently reporting stations were all manned, and so someone would go out and look and determine what kind of precip is falling.  Reports such as if it was raining or snowing, cloudy or sunny, are based on the observation at that moment, not over the course of time.  With technology, a simple camera and light source can determine precip type.  Snow reflects light back to the camera whereas rain lets the light pass through the drop.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Radar is a little more complicated.  We now use what is known as Duel Polarization (Duel-Pol) radars.  Using signals polarized in different directions, we can measure the shape of the precipitation.&lt;a href=&quot;https://i.stack.imgur.com/1LW3N.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1LW3N.jpg&quot; alt=&quot;Polarization diffiation&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wind resistance flattens out rain drops, making them wider than tall.  Hail tends to be round.  Snow may present itself on it's face appearing as hail, or side, appearing as rain.  The ratio of height to width gives the Spectral Differential Phase.  Snow has a lower value and rain has a higher value with some overlap.&#xA;Another important calculation is the Correlation Coefficient, which measures how similarly the two polarizations interact with the precip.  In the image below is a map of different precip types and their CC.  Note that snow has a much wider range of values than snow.  Snow type is determined by temperature, wet snow closer to freezing, drier snow as you get colder.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/OvI9s.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OvI9s.png&quot; alt=&quot;Correlation Coefficient&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These and other calculations give on the fly estimations for precipitation type.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, what you see on the radar on TV still uses the old way of mapping station reported temperatures onto the radar screen.  On this &lt;a href=&quot;http://severeweathervideo.com/Feb25_10_Regional_Radar.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;rain/snow radar loop&lt;/a&gt; You can make out the rain in green and yellow, the mix precip in pink, and snow in blue.  Note however the mix line (where the air is at 32°F/0°C, moves five times over the 10 frames, and it is not smooth.  This line is calculated by the measured temperatures from weather stations scattered over the area, drawing a line that marks the freezing point, much like drawing terrain contours.  While the radar updates every 10 minutes, weather stations are only sampled hourly or quarterly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So without knowing the exact way your data was gathered, I would say someone stuck their head out the window and marked on the computer that it was rain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Extra reading: &#xA;&lt;a href=&quot;http://www.nssl.noaa.gov/tools/radar/dualpol/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.nssl.noaa.gov/tools/radar/dualpol/&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.weather.gov/media/lmk/soo/Dual_Pol_Overview.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.weather.gov/media/lmk/soo/Dual_Pol_Overview.pdf&lt;/a&gt;&#xA;&lt;a href=&quot;http://training.weather.gov/wdtd/courses/dualpol/documents/DualPolRadarPrinciples.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://training.weather.gov/wdtd/courses/dualpol/documents/DualPolRadarPrinciples.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="10943" LastActivityDate="2017-09-02T19:04:55.717" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12211" PostTypeId="2" ParentId="12207" CreationDate="2017-09-02T22:29:04.630" Score="4" Body="&lt;p&gt;The agricultural regions of Canada:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/XRR0c.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XRR0c.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;are located on suitable soil types:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/4OhJ9.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4OhJ9.jpg&quot; alt=&quot;http://www.fao.org/ag/agp/agpc/doc/counprof/canada/pics/Figure%204b.jpg&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Much of the unfarmed area is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Canadian_Shield#Ecology&quot; rel=&quot;nofollow noreferrer&quot;&gt;Canadian Shield&lt;/a&gt; (shades of red below):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The current surface expression of the Shield is one of very thin soil&#xA;lying on top of the bedrock, with many bare outcrops. This arrangement&#xA;was caused by severe glaciation during the ice age, which covered the&#xA;Shield and scraped the rock clean. The lowlands of the Canadian Shield&#xA;have a very dense soil that is not suitable for forestation; it also&#xA;contains many marshes and bogs (muskegs). The rest of the region has&#xA;coarse soil that does not retain moisture well and is frozen with&#xA;permafrost throughout the year.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I think the &amp;quot;coarse soil&amp;quot; is &lt;a href=&quot;https://en.wikipedia.org/wiki/Till&quot; rel=&quot;nofollow noreferrer&quot;&gt;Glacial Till&lt;/a&gt;.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/s0kNs.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/s0kNs.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is melting permafrost. I don't think it will be suitable for agriculture.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ZwzM4.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZwzM4.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://act-adapt.org/wp-content/uploads/2013/07/07-13-CFS-Background-WEB.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;CLIMATE CHANGE ADAPTATION AND CANADA’S CROPS AND FOOD SUPPLY (2013)&lt;/a&gt; (122 pages) discusses warming, precipitation, soils and other factors.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;There is definitely potential for a northern expansion of agriculture&#xA;as a result of changes in heat and moisture in [the western prairies],&#xA;although most of these lands will remain only marginally suitable for&#xA;farming because of poor soil conditions.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Edit:&lt;a href=&quot;https://i.stack.imgur.com/EYX1i.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EYX1i.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;An eroding coastline exposes permafrost along the Mackenzie Delta. Photo: Roger McLeod / Natural Resources Canada&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;High resolution version&lt;/strong&gt; from &lt;a href=&quot;https://thenarwhal.ca/arctic-tundra-is-80-per-cent-permafrost-what-happens-when-it-thaws/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Arctic tundra is 80 per cent permafrost. What happens when it thaws?&lt;/a&gt; - The Narwhal:&lt;br /&gt;&#xA;&lt;a href=&quot;https://thenarwhal.ca/wp-content/uploads/2019/03/Coastal-Erosion-Permafrost-Roger-McLeod-NRCan--e1551913545654-1920x1080.jpeg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://thenarwhal.ca/wp-content/uploads/2019/03/Coastal-Erosion-Permafrost-Roger-McLeod-NRCan--e1551913545654-1920x1080.jpeg&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Edit, Oct., 2020:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://Canada%20could%20be%20a%20huge%20climate%20change%20winner%20when%20it%20comes%20to%20farmland&quot; rel=&quot;nofollow noreferrer&quot;&gt;Canada could be a huge climate change winner when it comes to farmland&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QF9sU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QF9sU.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;In this map from the study, areas that transition from no current suitability for major commodity crops to suitability for one or more crops are depicted in blue, while currently uncultivated areas that transition to suitability for multiple major commodity crops are shown in red. (&lt;a href=&quot;https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0228305&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hannah et al, 2020&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;KC acknowledged the study looked only at climate as a factor when determining where crops could be grown in the future, and didn't take into account things like soil quality.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Soil scientist David Burton of Dalhousie University, who wasn't involved in the study, says that could have a big impact on how much of the potential new farmland is actually arable.&#xA;&amp;quot;The soils of Southern Canada have taken 10,000 years to develop,&amp;quot; he said. &amp;quot;Rapid change wouldn't necessarily make soils in Northern Canada suitable for production.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Johanna Wandel, an associate professor of geography at the University of Waterloo who edited a book called Farming in a Changing Climate, agrees the soil in much of Canada would likely be unsuitable for growing crops, as it's too rocky or acidic.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2020-10-19T22:18:41.683" LastActivityDate="2020-10-19T22:18:41.683" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="12212" PostTypeId="1" CreationDate="2017-09-02T22:51:09.993" Score="7" ViewCount="263" Body="&lt;p&gt;I spotted this large striped rock found on Delaware River. Note the fossil in the first picture. What kind of rock is this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3rgoj.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3rgoj.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/0JcA8.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0JcA8.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/7dYD7.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7dYD7.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/jMeNR.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jMeNR.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="10946" LastEditorUserId="10681" LastEditDate="2017-09-13T00:07:51.640" LastActivityDate="2017-09-13T00:07:51.640" Title="What is the rock I found on the Delaware river yesterday?" Tags="|geology|rivers|" AnswerCount="1" CommentCount="1" ClosedDate="2019-08-29T11:54:49.110" ContentLicense="CC BY-SA 3.0" />
  <row Id="12213" PostTypeId="1" AcceptedAnswerId="12216" CreationDate="2017-09-03T05:47:36.523" Score="13" ViewCount="2643" Body="&lt;p&gt;IN the NPR news item North Korea Possibly Conducts Sixth Nuclear Test, South Korea Says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The U.S. Geological Survey says it detected a 6.3 magnitude &amp;quot;possible explosion&amp;quot; near Sungjibaegam, North Korea Sunday afternoon, &amp;quot;located near the site where North Korea has detonated nuclear explosions in the past.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;South Korean Joint Chiefs of Staff say they detected an &amp;quot;artificial seismic wave&amp;quot; at 12:29 p.m. local time and are &amp;quot;currently looking into the possibility of it being a nuclear test.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;The incident was near North Korea's Punggye-ri nuclear test site, which is in the country's northeast and the site of the five previous tests.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The magnitude and location of the event are strongly suggestive of the cause, but if the location were very different, it sounds like the nature of the seismic waves would already indicate that the source was &lt;em&gt;artificial rather than a natural geological seismic event&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What is it about a seismic wave measurements that would allow one to distinguish between natural geological and artificial causes?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; &amp;quot;North Korea has conducted six nuclear tests. As this chart of seismic activity shows, the latest test on Sept. 3 was roughly an order of magnitude larger than earlier ones.&amp;quot; From the NPR new item &lt;a href=&quot;http://www.npr.org/sections/thetwo-way/2017/09/07/549155856/here-s-how-big-north-korea-s-latest-nuclear-test-actually-was&quot; rel=&quot;noreferrer&quot;&gt;Here's How Big North Korea's Latest Nuclear Test Actually Was&lt;/a&gt;, Original: &lt;a href=&quot;http://ctbto.org/the-treaty/developments-after-1996/2017-sept-dprk/technical-findings/&quot; rel=&quot;noreferrer&quot;&gt;CTBTO&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cdLmi.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cdLmi.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-09-08T08:42:32.840" Title="What are the distinguishing features of an &quot;artificial seismic wave&quot; (e.g. a large underground explosion)" Tags="|earthquakes|seismic|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12214" PostTypeId="2" ParentId="12204" CreationDate="2017-09-03T09:30:41.177" Score="2" Body="&lt;p&gt;No, it is not undefined.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A relative humidity of 100% refers to cases in which the atmosphere holds as much water, as the temperature would allow. The term &quot;dry air&quot; denotes the fraction of the air not contaning any water vapor (or explicitly not any water molecules). Dry air is therefore never negligible in clouds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The saturation vapor pressure over a plane water surface can be calculated by the Magnus formula (which is an empirical approximation to the Clausius-Clapeyron-equation valid in a temperature range from -45°C to 60°C):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$E_{H_2O}(\vartheta)=6.112hPa \cdot exp{\frac{17.62 \cdot \vartheta}{243.15 ^\circ C + \vartheta}} $,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\vartheta$ is the temperature in °C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The water vapor mixing ration $r$ itself is calculated by:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$r=\frac{0.622e}{p-e}$,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $p$ is the air pressure and $e$ is the water vapor pressure. In case of a cloud you equate $e$ and $E_{H_2O}(\vartheta)$, since the relative humidity is defined as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$r.H.=\frac{e}{E_{H_2O} (\vartheta)}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a sidenote: Oversaturation in clouds may occur frequently but is usually smaller then 1%. For back-of-the-envelope-calculation this should be sufficient.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please note, that different text books use diffent symbols for $e, E, ...$&lt;/p&gt;&#xA;" OwnerUserId="10752" LastActivityDate="2017-09-03T09:30:41.177" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12215" PostTypeId="1" CreationDate="2017-09-03T11:55:19.093" Score="10" ViewCount="454" Body="&lt;p&gt;This may be a sort of, pertinent to the times, and disturbing question, inspired by the difficulties surrounding North Korea and the situation with it and nuclear weapons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've heard of this idea of &quot;nuclear winter&quot; that can result from a nuclear exchange, and more interestingly, very surprisingly, and disturbingly, that a major winter could be caused by even a &quot;small&quot; nuclear exchange, like on this paper:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://climate.envsci.rutgers.edu/pdf/WiresClimateChangeNW.pdf&quot; rel=&quot;noreferrer&quot;&gt;http://climate.envsci.rutgers.edu/pdf/WiresClimateChangeNW.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;suggests that only &quot;150 teragrams&quot; of &quot;smoke&quot; released from a Nuclear exchange, would be able to produce a HUGE temperature drop of 7 degrees C for a couple of years or so, with attendant devastating effects on agriculture - indeed there's another version of this I saw with a map showing far greater temperature drops, like 20 degrees C or more, in places like Europe and North America (the USA) over land, right where the breadbaskets would be. Considering that it's not just crops but other plants as well that would be affected, its would seem to be a geologically significant event for a fair number of life forms, not just humans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the thing I'm having trouble with is just how is this possible, in particular, this magnitude, because it seems to be comparable to, if not greater than, &lt;em&gt;natural&lt;/em&gt; events that would seemingly be of far greater magnitude. The 150 teragrams of carbon soot is only like a cube 400 meters on a side when solid, which is then vaporized and spread throughout the atmosphere, but that seems utterly tiny compared to the release of thousands of cubic kilometers of ash and other materials from volcanic and super-volcanic eruptions(*), much more asteroid strikes like Chicxulub releasing doubtless millions of cubic kilometers of material of all sorts. Is the soot really tens or hundreds of thousands of times more powerful per unit mass at cooling than anything released from any of these events would be? Or what? Further, especially considering that an event like Chicxulub would no doubt have ignited at least continent-scale areas of of forests in the area around it if nowhere else from the ejecta storm, which doubtless would have produced far more black carbon soot than burning down all the cities in a nuclear war, no? Yet this suggests effects that, while not equal, seem almost comparable - and this is considered for a much diminished set of arsenals, compared to what they were at their peak, suggesting the peak could perhaps even eclipse the Chicxulub at a tiny fraction of the total energy release from the latter. What would have happened to the Earth in an imaginary scenario where the 100 million megatons (400 zettajoules) of Chicxulub asteroid energy were replaced with 100 million megatons of hydrogen bomb mushroom clouds exploding over a comparable area of forests (alien attack? :) ) to those that the asteroid would have burned, 65-66 million years ago?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(*) See, e.g. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Toba_catastrophe_theory&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Toba_catastrophe_theory&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Toba_catastrophe_theory#Volcanic_winter_and_cooling&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Toba_catastrophe_theory#Volcanic_winter_and_cooling&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where it is mentioned how that the Toba super volcanic eruption was first thought to have produced a big cooling, but more recent evidence suggests it may not have. Yet the nuclear war seems able to almost match it, with only 150 teragrams of carbon vs. 6 000 teragrams of SO2. Now of course maybe the former is better absorber (gas vs. fine dark solid), but literally so much better that the latter could barely move the meter (according to observational evidence, not the simulation mentioned), while the former would drop it 7 degrees C, 20+ in some areas? And that's just the SO2 component, what about all the other material released by the eruption to no doubt similar very great heights? And furthermore, how does this all fit in with Chicxulub? Is there any data on the &quot;anti greenhouse&quot; power of C soot versus SO2 and other materials released by volcanoes and asteroid strikes?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short, what makes nuclear weapons so damn &lt;em&gt;good&lt;/em&gt; at being destructive, compared to everything that nature seems to have in its arsenal short of the death of the Sun itself, despite seemingly the much greater raw power in terms of energy of the latter?&lt;/p&gt;&#xA;" OwnerUserId="7283" LastEditorUserId="7283" LastEditDate="2017-09-18T12:04:23.950" LastActivityDate="2019-04-10T05:02:10.433" Title="What makes a nuclear winter so extreme and destructive?" Tags="|climate-change|paleoclimatology|climatology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12216" PostTypeId="2" ParentId="12213" CreationDate="2017-09-03T19:24:35.810" Score="14" Body="&lt;p&gt;Several things can indicate that a seismic event is an explosion and not an earthquake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Firstly, the depth of the source. The shallowest earthquakes tend to have a hypocentre that is at least a couple of km below the ground surface and some earthquakes in certain parts of the world can go down to about 700 km. Artificial explosions on the other hand, will be very shallow, with a hypocentre that is essentially at the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly, and more importantly, the P-wave radiation pattern (and S-wave as well) for an explosion is fundamentally different to that of an earthquake. This can be investigated by plotting the polarities of the first arriving waves of a seismic event on a stereonet, with the position on the net being determined by the azimuth of the source from the receiving station and the outgoing angle of the wave from the source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earthquakes radiate P-waves in four lobes, with alternating polarities. This is called a double couple source and it produces a fault plane solution with two positive and two negative quadrants. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;An explosion, radiates P-waves equally in all directions and so produces an isotropic pattern.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You may have seen reports of a second seismic event after the nuclear test which has been interpreted as a tunnel collapse. This also has a distinctive focal mechanism, called a compensated linear vector dipole (CLVD).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/O7zXu.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/O7zXu.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The photo shows directions of first motion at the source (a) (outwards = positive, inwards = negative), the P-wave radiation pattern (b), the steroplot of each focal mechanism (c).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These links give some further introduction to how stereonets are used to analyse earthquakes:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://ocw.mit.edu/courses/earth-atmospheric-and-planetary-sciences/12-510-introduction-to-seismology-spring-2010/lecture-notes/lec18.pdf&quot; rel=&quot;noreferrer&quot;&gt;https://ocw.mit.edu/courses/earth-atmospheric-and-planetary-sciences/12-510-introduction-to-seismology-spring-2010/lecture-notes/lec18.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.ucl.ac.uk/EarthSci/people/lidunka/GEOL2014/Geophysics4%20-%20Seismic%20waves/Seismology/Earthquake%20Seismology2.htm&quot; rel=&quot;noreferrer&quot;&gt;http://www.ucl.ac.uk/EarthSci/people/lidunka/GEOL2014/Geophysics4%20-%20Seismic%20waves/Seismology/Earthquake%20Seismology2.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://rses.anu.edu.au/~nick/teachdoc/lecture11.pdf&quot; rel=&quot;noreferrer&quot;&gt;http://rses.anu.edu.au/~nick/teachdoc/lecture11.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2570" LastEditorUserId="2570" LastEditDate="2017-09-04T18:33:24.913" LastActivityDate="2017-09-04T18:33:24.913" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12219" PostTypeId="2" ParentId="12213" CreationDate="2017-09-04T12:51:03.177" Score="3" Body="&lt;p&gt;A bit more information - total plagiarism from &#xA;&lt;a href=&quot;https://theconversation.com/qanda-what-earthquake-science-can-tell-us-about-north-koreas-nuclear-test-83415&quot; rel=&quot;nofollow noreferrer&quot;&gt;Q&amp;amp;A: what earthquake science can tell us about North Korea’s nuclear test&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Any sort of earthquake or explosion, whether natural or man-made, produces different sorts of shock waves which travel through the Earth and can be detected by seismometers, which can measure very small ground movements. The fastest waves to arrive are the primary waves (P waves), followed by secondary waves (S waves), which travel deep through the Earth. Then come the slower surface waves, which cause the most shaking felt at ground level because they only travel close to the surface.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Studies of the numerous nuclear tests that took place during the Cold War show that explosions generate larger P waves than S waves when compared with earthquakes. Explosions also generate proportionally smaller Surface waves than P waves. Seismologists can therefore compare the size of the different types of wave to try to determine whether the waves came from an explosion or a natural earthquake.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Seismological data can tell us whether there was an explosion, but not whether that explosion was caused by a nuclear warhead or conventional explosives. For final confirmation that an explosion was nuclear, we have to rely on radionuclide monitoring, or experiments at the test site itself.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Similarly, we cannot explicitly differentiate between a nuclear fission bomb and a thermonuclear hydrogen bomb, nor can we tell if a bomb is small enough to be mounted on a missile&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-09-04T12:51:03.177" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12221" PostTypeId="1" CreationDate="2017-09-04T19:42:50.063" Score="3" ViewCount="1728" Body="&lt;p&gt;Of course the mountains were caused by moving tectonic plates. But in case of the Himalaya mountains was the speed of the plates just higher so more energy got 'into' the mountains. Or was the continental plates just slightly more loose on the plates? Or did the plates just submerge more, if so what caused that? Or....&lt;/p&gt;&#xA;" OwnerUserId="5372" LastActivityDate="2017-10-13T03:54:48.213" Title="What allowed the Himalaya to become so high?" Tags="|geology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12222" PostTypeId="2" ParentId="12213" CreationDate="2017-09-04T22:47:04.027" Score="1" Body="&lt;p&gt;Not a full answer, since the other two are pretty much spot on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another telltale sign of an artificial &quot;event&quot; is, unsurprisingly, timing. Historically, shots are more often conducted at &quot;round&quot; times - here, at (almost) 30 minutes past the hour.&lt;/p&gt;&#xA;" OwnerUserId="10960" LastActivityDate="2017-09-04T22:47:04.027" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12223" PostTypeId="1" AcceptedAnswerId="12224" CreationDate="2017-09-05T03:07:44.497" Score="24" ViewCount="14875" Body="&lt;p&gt;Today was a normal day, except the sun and moon colors were strange. After 5pm, the sky was covered with cirrostratus-like translucent clouds and the sky was a blend of blue and grey.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Everything would be fine, except that the sun was orange between 4-5pm. Then by around 5-6pm, the sun was completely red like blood even though it was still high up, and it was 1+ more hour to sunset.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then, I didn't look at the sky until 8pm when it was already dark. When I went out, the moon was red just like the sun couple hours before.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The whole thing I saw from around south side od Chicago on US Labor Day (4 Sep, 2017). I didn't take pictures of the sun unfortunately because I disregarded its color, but I took pictures of the moon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's how the moon looked through my phone camera, through binoculars:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/XrGxO.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XrGxO.jpg&quot; alt=&quot;Red moon 1&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a similar picture but edited so that the moon looks exactly like I saw it with naked eye:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/cmvCi.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cmvCi.jpg&quot; alt=&quot;Red moon 2&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What can thia be caused by?&lt;/strong&gt; (As of writing this at 10:06pm the moon is still red, and it is 6 hours since both the sun and the moon were red/orange)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT: I also didn't see anything about this phenomenon in the media which is strange, and once again, this was seen from Chicago.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6148" LastEditorUserId="6148" LastEditDate="2017-09-05T03:15:28.270" LastActivityDate="2017-09-06T12:51:28.193" Title="Why were both the sun and the moon red today?" Tags="|atmosphere|moon|sun|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="12224" PostTypeId="2" ParentId="12223" CreationDate="2017-09-05T04:04:57.597" Score="39" Body="&lt;p&gt;Smoke.  There was significant smoke across the USA, which attenuated the light from the sun/moon due to increased scattering.  The smoke particles effectively cause the light to reflect in different directions, so you see more colors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See below for the &lt;a href=&quot;http://www.ospo.noaa.gov/Products/land/hms.html&quot; rel=&quot;noreferrer&quot;&gt;HMS Smoke Polygons&lt;/a&gt; for the day, which clearly shows smoke over your region from the intense smoke/wildfire activity in the Pacific Northwest.  You can also see the &lt;a href=&quot;https://worldview.earthdata.nasa.gov/&quot; rel=&quot;noreferrer&quot;&gt;NASA Worldview&lt;/a&gt; composite of VIIRS visible imagery for the day, with fire locations in red.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KMh5k.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KMh5k.jpg&quot; alt=&quot;HMS&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wUiDU.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wUiDU.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2017-09-05T04:39:51.637" LastActivityDate="2017-09-05T04:39:51.637" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12225" PostTypeId="2" ParentId="12221" CreationDate="2017-09-05T05:01:55.117" Score="1" Body="&lt;p&gt;It mostly has to do with the type of convergent boundary the  Himalayas are, continental crust to continental crust. Most convergent boundaries are oceanic to continental or oceanic to oceanic. In both cases there is a dense oceanic plate that can get subducted. But in a continental crust to continental crust collision neither can really dive under the other and get reworked*, since both are low density, thick, and roughly equal in density, so they just compress together like pushing two wads of clay together. They build both up and down since they sort of float on the rock below. Think of it kinda like a geologic iceberg, it is too light to sink. All compressive collisions  thicken like this to a lesser extent, due to the compressive forces, it is just far more intense with continental to continental collisions because there is no other outlet for the energy but compression because all the material involved is to light to be subducted. . &lt;/p&gt;&#xA;&#xA;&lt;p&gt;the Eurasian and Indian plates are both large continental plates so as long as they are getting forced together they can only get thicker and thicker. This is the only boundary like this on earth right now, so it seems weird to us, but this type of collision has happened before they are just rarer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;*sometimes one does go down more than the other but it does not get reworked, they just get fused together in a lopsided fashion. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2017-09-05T15:37:58.867" LastActivityDate="2017-09-05T15:37:58.867" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12227" PostTypeId="2" ParentId="12212" CreationDate="2017-09-05T13:31:40.500" Score="3" Body="&lt;p&gt;The boulder appears to be dark grey  fossiliferous limestone or dolostone with softer tan layers which might be: limestone or calcareous claystone/siltstone/sandstone.&#xA;From the photo, the tan layers do not appear to be shale.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have a hand specimen which is very similar from southern New Jersey.&#xA;It is harder grey limestone inter-layered with light tan calcareous siltstone.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/8YUOj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8YUOj.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-09-05T13:31:40.500" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12229" PostTypeId="1" CreationDate="2017-09-05T15:03:54.563" Score="1" ViewCount="44" Body="&lt;p&gt;In many cases when I find interesting rocks they are worn and rounded off so the crystalline structure is not clear.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can I determine what kind of crystal it is in those cases?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a simple instrument that can be used to determine the angle of a crystal, even if it is worn and rounded?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2017-09-06T09:56:29.227" Title="How can crystal habit be determined when rock is worn and rounded?" Tags="|crystallography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12230" PostTypeId="1" AcceptedAnswerId="14973" CreationDate="2017-09-05T17:18:50.690" Score="6" ViewCount="143" Body="&lt;p&gt;Hurricanes are classified with the Saffir–Simpson hurricane wind scale. However an extreme  amount of rainfall can cause a disaster although the windspeeds are not extreme. Is there some sort of classification where estimated rainfall caused by a hurricane is taken into account?&lt;/p&gt;&#xA;" OwnerUserId="10681" LastEditorUserId="10681" LastEditDate="2018-08-28T19:29:46.730" LastActivityDate="2018-08-29T15:04:58.303" Title="Does a hurricane classification exists where estimated rainfall is taken into account?" Tags="|meteorology|hydrology|precipitation|tropical-cyclone|rainfall|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12234" PostTypeId="2" ParentId="12180" CreationDate="2017-09-05T22:07:25.317" Score="3" Body="&lt;p&gt;Perhaps the &lt;a href=&quot;https://www.ngdc.noaa.gov/nndc/struts/form?t=101650&amp;amp;s=1&amp;amp;d=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Significant Earthquake Database request form&lt;/a&gt; from NOAA would help?&lt;/p&gt;&#xA;" OwnerUserId="5448" LastEditorUserId="6298" LastEditDate="2017-09-06T07:27:56.363" LastActivityDate="2017-09-06T07:27:56.363" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12237" PostTypeId="2" ParentId="12229" CreationDate="2017-09-06T09:56:29.227" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is there a simple instrument&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A geological hammer. Seriously. Once you smash a rock, you reveal fresh cleavage planes, grain boundaries, less weathered zones, etc. The downside is that it's destructive.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;angle of a crystal, even if it is worn and rounded?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Here you're assuming that crystals that are not worn or rounded have their original crystal shape. This is rarely the case. These crystals, known as &quot;euhedral&quot; are the exception, not the rule. A good example is feldspar phenocrysts in granites, or some elongated amphiboles. Maybe phenocrysts of pyroxene in basalts. More commonly, crystals are just shapeless, also known as &quot;anhedral&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A more advanced form of rock and mineral study is called petrography - this requires thin sectioning abilities and a petrographical microscope. Basic tools that exist in all geological departments at universities, but probably not accessible to amateurs.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-09-06T09:56:29.227" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12239" PostTypeId="1" AcceptedAnswerId="12274" CreationDate="2017-09-06T15:28:59.907" Score="2" ViewCount="128" Body="&lt;p&gt;I know nothing significant about meteorology and definitely not a science guy so this will probably seem naive...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But today I am wondering if there is any existing science or methods a government (with enough funds) could employ, through science, to lessen the force of a hurricane?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I vaguely remember something about them being affected by air temperatures, so couldn't something be done to somehow inject heat or refrigeration into the area? Or something to counteract against it's speed increases?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What approaches would one consider in such an endeavor?&lt;/p&gt;&#xA;" OwnerUserId="10994" LastEditorUserId="2536" LastEditDate="2017-09-27T22:56:13.667" LastActivityDate="2017-09-27T22:56:13.667" Title="Ways, Through Science, to Counteract Hurricane Forces?" Tags="|meteorology|tropical-cyclone|geoengineering|" AnswerCount="1" CommentCount="14" ContentLicense="CC BY-SA 3.0" />
  <row Id="12240" PostTypeId="1" CreationDate="2017-09-06T23:52:36.140" Score="2" ViewCount="792" Body="&lt;p&gt;So there's a sea, right by my house. How do I know if it's been explored, and what info do we have about it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the internet, about 5-10% of the world's oceans has been explored.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a map that shows which parts of the ocean have been explored, and which haven't? Does it show what has been discovered about X part of the ocean etc.? Where can I find such information?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I just google &quot;Unexplored parts of the world&quot;, it'd drive me to very specific and popular parts of the earth, many of which have actually been explored (to a certain point), such as the Mariana Trench etc.&lt;/p&gt;&#xA;" OwnerUserId="10996" LastEditorUserId="595" LastEditDate="2017-09-07T06:15:54.737" LastActivityDate="2017-09-07T06:15:54.737" Title="Which parts of the ocean have been explored?" Tags="|ocean|oceanography|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="12242" PostTypeId="1" CreationDate="2017-09-07T04:04:15.223" Score="4" ViewCount="234" Body="&lt;p&gt;I was just wondering about the large waves associated with storms. It seems a little counter-intuitive that large masses of water can be put into motion by moving air (which is much lighter than water). It must take a lot less energy to set a wave oscillating than I am expecting. I'd appreciate an explanation from first principles, though.&lt;/p&gt;&#xA;" OwnerUserId="10750" LastActivityDate="2017-09-12T22:20:21.790" Title="How does wind cause large waves?" Tags="|wind|waves|storms|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12243" PostTypeId="2" ParentId="12240" CreationDate="2017-09-07T04:17:23.353" Score="5" Body="&lt;p&gt;The simplest way to find out the basic information about your nearby ocean is to check &lt;a href=&quot;https://www.google.com/earth/&quot; rel=&quot;noreferrer&quot;&gt;Google Earth&lt;/a&gt;, which has an &lt;a href=&quot;https://www.google.com/earth/explore/showcase/ocean.html&quot; rel=&quot;noreferrer&quot;&gt;Ocean&lt;/a&gt; layer that often includes details about noteworthy features and discoveries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://scripps.ucsd.edu/news/around-pier-new-global-seafloor-map-incorporated-google-ocean&quot; rel=&quot;noreferrer&quot;&gt;This story from Scripps Institution of Oceanography&lt;/a&gt; explains some of the updates that were made in late 2015:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The new global gravity map, recently published by [geophysicist David] Sandwell and&#xA;  colleagues in the journal Science, was used in combination with&#xA;  available depth soundings to provide a more detailed picture of the&#xA;  mountains and valleys along Earth’s most unexplored expanse – the&#xA;  ocean floor.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.scientificamerican.com/article/just-how-little-do-we-know-about-the-ocean-floor/&quot; rel=&quot;noreferrer&quot;&gt;This essay in Scientific American&lt;/a&gt; helps explain some of the extent of our knowledge:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;So the “95% unexplored” meme doesn’t really tell the full story of our&#xA;  exploration of the oceans. When it comes to having a large-scale map,&#xA;  the ocean floor is perhaps not as unexplored as we might think, with&#xA;  100% coverage to a resolution of 5km and 10%-15% coverage at around&#xA;  100m resolution. That 10%-15% is similar in resolution to the current&#xA;  global maps of Mars and Venus.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;But our exploration of the oceans depends on what we want to know&#xA;  about them. If our questions are: “What does it look like down there?”&#xA;  or: “What’s going on down there?”, then the area that has been&#xA;  “explored” is arguably even less than the 0.05% mapped so far at the&#xA;  very highest resolution by sonar.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The areas mapped in most detail will be near coasts and common ship routes. Oceanographic vessels run their sonar systems almost continuously, so the maps will have lines of very high resolution detail running through them (artifacts that are often interpreted to look like lost cities or roadways).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But surprising discoveries are still made. It was only in 2012 that &lt;a href=&quot;https://scripps.ucsd.edu/news/1779&quot; rel=&quot;noreferrer&quot;&gt;a Scripps expedition found a methane seep&lt;/a&gt; that was &lt;a href=&quot;https://scripps.ucsd.edu/news/scripps-video-news-release-researchers-release-details-recently-discovered-del-mar-seep&quot; rel=&quot;noreferrer&quot;&gt;later determined to support an elaborate chemosynthetic ecosystem&lt;/a&gt; just 20 miles off the coast of Del Mar in Southern California.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2017-09-07T04:17:23.353" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12244" PostTypeId="1" AcceptedAnswerId="12245" CreationDate="2017-09-07T05:38:25.680" Score="4" ViewCount="182" Body="&lt;p&gt;I was reading the Wikipedia article about a mathematical subject called &lt;a href=&quot;https://en.wikipedia.org/wiki/Projective_geometry&quot; rel=&quot;noreferrer&quot;&gt;projective geometry&lt;/a&gt;, and I noticed that the second image in the body of the article referred to the &quot;growth of polar vortices&quot;. The only use of the term &lt;a href=&quot;https://en.wikipedia.org/wiki/Polar_vortex&quot; rel=&quot;noreferrer&quot;&gt;polar vortex&lt;/a&gt; that I'm aware of is in meteorology:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A polar vortex is an upper level low-pressure area lying near the Earth's pole. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Can anyone recognize how this drawing &lt;em&gt;might relate in any way&lt;/em&gt; to meteorological polar vortices? &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;From the Wikipedia article &lt;a href=&quot;https://en.wikipedia.org/wiki/Projective_geometry&quot; rel=&quot;noreferrer&quot;&gt;Projective Geometry&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Caption:&lt;/strong&gt; &quot;Growth measure and the polar vortices. Based on the work of Lawrence Edwards&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Iwqrt.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Iwqrt.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2017-09-07T05:53:23.583" LastActivityDate="2017-09-07T07:50:07.340" Title="Growth of polar vortices vs projective geometry; what does this figure mean?" Tags="|meteorology|terminology|mathematics|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12245" PostTypeId="2" ParentId="12244" CreationDate="2017-09-07T07:50:07.340" Score="2" Body="&lt;p&gt;I suspect that this diagram has nothing to do with polar vortices in the meteorological sense. It’s hard to prove a negative, but digging into the source of this image led me in some very non-meteorological directions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Growth_measure_and_vortices.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;file itself&lt;/a&gt; is entitled ‘Growth measure and vortices’ on Wikimedia (note absence of ‘polar’), with a source of ‘own work’ (by the user ‘Snowy Weather’) and the description ‘Projective geometry block in a Waldorf high school’.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apart from the ‘Projective geometry’ page, the only Wikipedia page using this image is the one on &lt;a href=&quot;https://en.wikipedia.org/wiki/Waldorf_education&quot; rel=&quot;nofollow noreferrer&quot;&gt;Waldorf education&lt;/a&gt;, where it’s described as ‘Student work from a projective geometry block in a Waldorf high school’. The image was added to both the &lt;a href=&quot;https://en.wikipedia.org/w/index.php?title=Projective_geometry&amp;amp;diff=618435320&amp;amp;oldid=611263327&quot; rel=&quot;nofollow noreferrer&quot;&gt;projective geometry article&lt;/a&gt; and the &lt;a href=&quot;https://en.wikipedia.org/w/index.php?title=Waldorf_education&amp;amp;diff=531490999&amp;amp;oldid=531489396&quot; rel=&quot;nofollow noreferrer&quot;&gt;Waldorf article&lt;/a&gt; by the &lt;a href=&quot;https://en.wikipedia.org/wiki/User:Clean_Copy&quot; rel=&quot;nofollow noreferrer&quot;&gt;same user&lt;/a&gt; (not the original uploader of the image), who doesn't seem to have any background in meteorology. This makes me suspect that the ‘polar’ may have been added in error.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the ‘Projective geometry’ page, the image is described as being ‘based on the work of Lawrence Edwards’. Almost certainly, this must refer to Edwards’ book &lt;a href=&quot;http://a.co/3upfXu4&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Projective Geometry&lt;/em&gt;&lt;/a&gt;, which seems from the reviews to be rather esoteric:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;‘The reason why modern materialists are unable to understand anything of a spiritual nature is that their ways of thinking, based purely upon sense perception, are much too rigid. Books such as this can help loosen such rigidity.’&lt;/li&gt;&#xA;&lt;li&gt;‘… some of the terms that Edwards uses (e.g. &quot;breathing involution&quot;) may actually be his own creation… and this made cross-referencing the book with other projective geometry texts a little harder.’&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The same author has written a book entitled &lt;a href=&quot;http://a.co/9B9tWqp&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;The Vortex of Life&lt;/em&gt;&lt;/a&gt; – again, not related to meteorology – suggesting to me that he may be quite keen on the word ‘vortex’, perhaps in a broader or more unusual sense than one might find in the mainstream of scientific literature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short: the word ‘polar’ may or may not have been added in error by a Wikipedia editor, but in either case I am fairly confident that the ‘polar vortices’ referred to here have nothing to do with meteorology.&lt;/p&gt;&#xA;" OwnerUserId="94" LastActivityDate="2017-09-07T07:50:07.340" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12246" PostTypeId="1" CreationDate="2017-09-07T18:17:27.363" Score="2" ViewCount="197" Body="&lt;p&gt;Mesocyclones form when air rises and rotates in a &quot;pillar&quot; of sorts. It's sometimes associated with thunderclouds and tornado formation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A certain kind of cumulonimbus, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cumulonimbus_flammagenitus_(cloud)&quot; rel=&quot;nofollow noreferrer&quot;&gt;cumulonimbus flammagenitus&lt;/a&gt;, can form above a firestorm of sufficient strength (magnitude, temperature, whatever the thing being measured is). Some cumulonimbus flammagenitus clouds have generated true &lt;a href=&quot;https://www.youtube.com/watch?v=-WNXDLlFCvg&quot; rel=&quot;nofollow noreferrer&quot;&gt;fire tornado&lt;/a&gt;s (as opposed to the fire whirl, which is commonly called a fire tornado) indicating that these clouds do form mesocyclones. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is, could a firestorm generate a hurricane-like cyclone, with strong surface winds along a large area, raining ash and embers? If so, would it move or be stationary? How long could it sustain itself? What would be involved in its formation?&lt;/p&gt;&#xA;" OwnerUserId="11005" LastEditorUserId="2536" LastEditDate="2017-09-07T23:21:49.030" LastActivityDate="2018-06-13T21:42:13.163" Title="Could a firestorm create a hurricane-like cyclone?" Tags="|meteorology|atmosphere|severe-weather|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12247" PostTypeId="1" CreationDate="2017-09-07T18:53:41.750" Score="4" ViewCount="2589" Body="&lt;p&gt;What is the best method for calculating radius of influence for a pump well in an unconfined aquifer?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know the aquifer transmissivity (T), storativity (S), pump rate (Q), aquifer thickness (b), saturated thickness (h), and I have a rough idea of the aquifer recharge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have two thoughts for calculating ROI:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1) I could use the Thiem-Dupuit Method and back calc for my radius (r2) at which the drawdown is 0. There is a nearby well being pumped at a similar rate and I am applying the drawdown at this well (r1) to my own well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/uiQPo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uiQPo.png&quot; alt=&quot;Thiem-Dupuit&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) I could use an empirical method like one found &lt;a href=&quot;http://hatariwater.tumblr.com/post/138690184404/overview-of-the-radius-of-influence&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, but I noticed I get very different values for my ROI compared to what I calculate using Dupuit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have any insight or experience in this matter, I would greatly appreciate your help. Thank you!&lt;/p&gt;&#xA;" OwnerUserId="11004" LastActivityDate="2017-09-07T18:53:41.750" Title="Radius of Influence - groundwater pump well" Tags="|groundwater|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12248" PostTypeId="1" CreationDate="2017-09-08T00:07:35.483" Score="3" ViewCount="352" Body="&lt;p&gt;I have a time series of snow and temperature and I want to analyze changes over time for a specific period of time: 15 April - 15 June. In the perpetual calendar April 15 is the day 105 and in a leap year is 106. How should I handle/correct for leap years? Should I subtract one day on leap years? Is there a bias in the data because of leap years? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;thanks for you answers!&lt;/p&gt;&#xA;" OwnerUserId="7256" LastActivityDate="2017-09-08T00:07:35.483" Title="How to handle leap years when working with environmental conditions time series?" Tags="|temperature|snow|time|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12250" PostTypeId="1" CreationDate="2017-09-08T07:18:35.733" Score="1" ViewCount="845" Body="&lt;p&gt;What does strata mean here ?&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;These consolidated layered &lt;strong&gt;strata&lt;/strong&gt; are known as stratified rocks. The&#xA;  strata vary in thickness and may be tilted or horizontal. The&#xA;  sediments consist of loose particles of gravel, sand, silt in various&#xA;  proportions hence are porous and permeable.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It comes from a chapter called &lt;em&gt;Materials of The Earth Crust-Rocks&lt;/em&gt; from Frank Morden's Geography Class IX Part 1&lt;/p&gt;&#xA;" OwnerUserId="11008" LastEditorUserId="595" LastEditDate="2019-01-24T08:22:48.963" LastActivityDate="2019-01-24T08:23:27.413" Title="What does strata mean here?" Tags="|geology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="12251" PostTypeId="1" CreationDate="2017-09-08T07:55:46.010" Score="1" ViewCount="92" Body="&lt;p&gt;So people with common names don't have to share names with a destructive hurricane.&lt;/p&gt;&#xA;" OwnerUserId="11009" LastActivityDate="2017-09-08T15:20:02.697" Title="Why don't they give hurricanes uncommon names?" Tags="|weather-forecasting|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12252" PostTypeId="2" ParentId="12250" CreationDate="2017-09-08T08:58:59.863" Score="3" Body="&lt;p&gt;Strata always mean a collection of layers. A single layer is called a stratum. The plural of stratum is strata.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="595" LastEditDate="2019-01-24T08:23:27.413" LastActivityDate="2019-01-24T08:23:27.413" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="12253" PostTypeId="2" ParentId="12251" CreationDate="2017-09-08T09:46:26.840" Score="6" Body="&lt;p&gt;It's just the system that is used.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first person to give names to cyclones/typhoons/hurricanes was &lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/B1.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Clement Wragge&lt;/a&gt;, an Australian weather forecaster in the 19 century.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;He first designated tropical cyclones by the letters of the Greek alphabet, then started using South Sea Island girls' names. When the new constituted Australian national government failed to create a federal weather bureau and appoint him director, he began naming cyclones &quot;after political figures whom he disliked. By properly naming a hurricane, the weatherman could publicly describe a politician (who perhaps was not too generous with weather-bureau appropriations) as 'causing great distress' or 'wandering aimlessly about the Pacific.'&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;During World War 2, US army &amp;amp; navy meteorologists name tropical cyclones after their wives, after having been introduced to a novel, &lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Storm_(novel)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Storm&lt;/a&gt;&lt;/em&gt;, in which a junior meteorologist named extra-tropical storms after girl friends.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In 1947 the US Air Force Hurricane Office in Miami started using the then new international phonetic alphabet (Able, Baker, Charlie, ...) when naming hurricanes in the North Atlantic Ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the international phonetic alphabet changed in 1952 (to Alpha, Beta, Charlie ,..) The US Weather Bureau initially started using the armed services practice of using women's names.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In 1975 the Australian Bureau of Meteorology started using a system alternating womens and mens names. After political pressure, in 1979 by the &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;US National Hurricane Center (NHC) requested that the WMO's Region IV Hurricane Committee switch to a hurricane name list that alternated men's and women's names following the practice adopted by Australia's Bureau of Meteorology in 1975. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;IN the North West Pacific, womens names were first used in 1945. Mens names started being used in 1979. Now they use a series of Asian names, contributed by nations and territories that are members of the WMO Typhoon Committee.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="6467" LastEditDate="2017-09-08T15:20:02.697" LastActivityDate="2017-09-08T15:20:02.697" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12254" PostTypeId="2" ParentId="5347" CreationDate="2017-09-08T13:15:41.857" Score="0" Body="&lt;p&gt;The high temperatures may have been at least partly caused by subsidence in the troposphere, which inhibited convection and hence convective storms. Subsidence also contributes to high temperatures due to the heat of compression as air is forced to sink, enhancing heat due to insolation. Subsidence is common in the troposphere over deserts such as the Sahara that lie in the horse latitudes, where air from the tropical Hadley cell circulation subsides. It contributes to the lack of rainfall in these deserts, and to some extent also to the high temperatures. Of course, insolation in the tropical deserts is so strong that temperatures would still be high even without subsidence, but not as high as with it.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-09-08T13:15:41.857" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12255" PostTypeId="1" CreationDate="2017-09-08T17:23:03.460" Score="3" ViewCount="123" Body="&lt;p&gt;Large hurricanes can show up on seismographs. Do they do this by shaking the ground with wind? Moving large amounts of water putting weight on the tectonic plates?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A large earthquake is the result of long term tectonic forces, but I wonder if local weather activity could trigger earthquakes?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this obviously impossible?&lt;/p&gt;&#xA;" OwnerUserId="2802" LastActivityDate="2017-09-08T17:23:03.460" Title="Can hurricanes set off earthquakes?" Tags="|earthquakes|tropical-cyclone|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12257" PostTypeId="1" CreationDate="2017-09-08T18:24:33.857" Score="3" ViewCount="196" Body="&lt;p&gt;The maximum potential intensity (&lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_cyclone#Maximum_potential_intensity&quot; rel=&quot;nofollow noreferrer&quot;&gt;MPI&lt;/a&gt;) is a computed quantity that often sets a maximum bound for maximum hurricane wind speed, though rarely, the wind speeds observed can exceed it. MPI is based off of the idea that hurricanes effectively work as Carnot engines. Has there been a table produced with historic MPI calculations (reanalysis or forecast based)?&lt;/p&gt;&#xA;&lt;p&gt;Also, is there a source that calculates MPI for each model and each hurricane?&lt;/p&gt;&#xA;&lt;p&gt;For reference, &lt;span class=&quot;math-container&quot;&gt;$$v_{MPI}=\sqrt{\frac{C_k(T_s-T_0)}{C_dT_0}\Delta k}=\sqrt{\frac{T_sC_k}{T_0C_d}(CAPE_s-CAPE_b)}$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$v_{MPI}$&lt;/span&gt; is the theoretical maximum speed (MPI), &lt;span class=&quot;math-container&quot;&gt;$C_k$&lt;/span&gt; is the surface drag coefficient of enthalpy, &lt;span class=&quot;math-container&quot;&gt;$C_D$&lt;/span&gt; is the surface drag coefficient, &lt;span class=&quot;math-container&quot;&gt;$\Delta k$&lt;/span&gt; is the change in enthalpy between the surface and environment, &lt;span class=&quot;math-container&quot;&gt;$T_s$&lt;/span&gt; is the sea surface temperature, &lt;span class=&quot;math-container&quot;&gt;$T_0$&lt;/span&gt; is the outflow temperature, &lt;span class=&quot;math-container&quot;&gt;$CAPE_s$&lt;/span&gt; is the convective available potential energy (CAPE) from sea level and &lt;span class=&quot;math-container&quot;&gt;$CAPE_b$&lt;/span&gt; is the&#xA;CAPE of the boundary layer air.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-11-12T00:06:47.040" Title="Is there a table available for the maximum potential intensity of hurricanes?" Tags="|wind|tropical-cyclone|thermodynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12258" PostTypeId="1" AcceptedAnswerId="12295" CreationDate="2017-09-09T01:37:24.580" Score="3" ViewCount="615" Body="&lt;p&gt;I am not a meteorologist but watching Hurricane Irma (2017), I have a couple questions about how hurricanes keep their formation based on geographical landmarks.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;How does the radius of the hurricane's eye affect the winds felt by&#xA;those at different distances from the eye?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;When a hurricane reaches land, how does the land affect the eye's&#xA;formation?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="11012" LastEditorUserId="6298" LastEditDate="2017-10-18T13:01:02.460" LastActivityDate="2018-02-15T15:29:57.947" Title="Hurricane eye on landfall and relation to wind speeds" Tags="|tropical-cyclone|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12260" PostTypeId="1" CreationDate="2017-09-09T04:20:06.867" Score="1" ViewCount="86" Body="&lt;p&gt;I found this stone on the bank of the Fraser River in southern BC and wonder what type of rock it is? I've never seen one like it before. Can you help me? Thank you &lt;img src=&quot;https://i.stack.imgur.com/tagc6.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pDX07.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="11014" LastActivityDate="2017-09-09T04:20:06.867" Title="First stone like this" Tags="|geology|" AnswerCount="0" CommentCount="4" ClosedDate="2019-09-16T11:10:50.830" ContentLicense="CC BY-SA 3.0" />
  <row Id="12261" PostTypeId="1" AcceptedAnswerId="12269" CreationDate="2017-09-09T09:27:07.377" Score="3" ViewCount="1096" Body="&lt;p&gt;Forgive my ignorance, I'm out of my depth.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My wife has pointed to the upsurge climate and geological activity post Eclipse.  My immediate response, at least inwardly, was to reject her suspicion.  However, the tectonic plate shift yesterday, in Mexico was substantial and the constant interplay of nature's  habits seems more robust than usual.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there substance to her hypothesis / theory, that the Eclipse and recent events on Earth are interrelated? &lt;/p&gt;&#xA;" OwnerUserId="11016" LastEditorUserId="7333" LastEditDate="2017-09-09T20:02:18.267" LastActivityDate="2017-09-22T11:53:41.763" Title="Eclipse, Hurricanes, Earthquake....Related Events?" Tags="|meteorology|planetary-science|geography|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12262" PostTypeId="1" CreationDate="2017-09-09T09:38:53.830" Score="3" ViewCount="294" Body="&lt;p&gt;A glass, as I understand it, is a material whose solid phase is amorphous and which undergoes a glass transition when heated.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My train of thought - and therefore my questions - began with obsidian.  My understanding is that obsidian is formed from material that would normally form crystalline rock, but since it's exposed to air during an eruption, it cools too rapidly to crystallize and therefore solidifies as glass.  This led me to wonder: how large can a lava stream be and still produce obsidian?  In particular, in season 7 of &lt;em&gt;Game of Thrones&lt;/em&gt;, the island of Dragonstone is revealed to contain a veritable mountain of obsidian - is such a thing possible in the real world?  I would have thought that, above a certain volume, the center of the mass would be well-enough insulated so that crystallization could occur, spoiling the obsidian.  What's the largest mass of obsidian found in nature?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thinking about too-rapid cooling led me to another question: can water form glass?  Is it possible to blast-freeze water so quickly that ice crystals do not form?  If so, what would be the properties of such a glass?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, I wonder about regular, garden-variety silicate glass (as found in windows and bottles.)  Can it be cooled slowly enough so that crystals &lt;em&gt;do&lt;/em&gt; form?  And if so, what are its properties?  (Have I essentially re-invented quartz?)&lt;/p&gt;&#xA;" OwnerUserId="11015" LastActivityDate="2017-09-11T07:29:33.857" Title="A few questions about glass" Tags="|rocks|ice|crystals|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12263" PostTypeId="2" ParentId="12261" CreationDate="2017-09-09T12:35:09.497" Score="11" Body="&lt;p&gt;The occurrences of Hurricanes, &lt;a href=&quot;https://en.wikipedia.org/wiki/Hurricane_Harvey&quot; rel=&quot;noreferrer&quot;&gt;Harvey&lt;/a&gt;, &lt;a href=&quot;https://earthobservatory.nasa.gov/IOTD/view.php?id=90931&quot; rel=&quot;noreferrer&quot;&gt;Irma, Katia and Jose&lt;/a&gt;, east of Mexico and a &lt;a href=&quot;https://earthquaketrack.com/quakes/2017-09-08-04-49-21-utc-8-1-69&quot; rel=&quot;noreferrer&quot;&gt;magnitude 8.1 earthquake southwest of Mexico&lt;/a&gt; within a few weeks of the &lt;a href=&quot;http://www.weather.gov/gsp/eclipse&quot; rel=&quot;noreferrer&quot;&gt;American solar eclipse of August 21, 2017&lt;/a&gt; are purely co-incidental.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Hurricane_Katrina&quot; rel=&quot;noreferrer&quot;&gt;Hurricane Katrina&lt;/a&gt;, which devastated New Orleans in 2005 was not associated with any type of eclipse - &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_eclipse&quot; rel=&quot;noreferrer&quot;&gt;solar&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Lunar_eclipse&quot; rel=&quot;noreferrer&quot;&gt;lunar&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Likewise the &lt;a href=&quot;https://en.wikipedia.org/wiki/1980_eruption_of_Mount_St._Helens&quot; rel=&quot;noreferrer&quot;&gt;eruption of Mt St Helens&lt;/a&gt; in May 1980 was not associated with any type of eclipse, or were  the &lt;a href=&quot;https://en.wikipedia.org/wiki/1906_San_Francisco_earthquake&quot; rel=&quot;noreferrer&quot;&gt;San Francisco earthquake of April 1906&lt;/a&gt; or the &lt;a href=&quot;https://en.wikipedia.org/wiki/1989_Loma_Prieta_earthquake&quot; rel=&quot;noreferrer&quot;&gt;Loma Prieta earthquake of October 1989&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a list of &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_solar_eclipses_in_the_20th_century&quot; rel=&quot;noreferrer&quot;&gt;every solar eclipse that occurred globally during the 20th Century&lt;/a&gt;. From the list, you will see there were one to two solar eclipses every year during the past century. None of these have ever been associated with any natural event such as earthquakes or hurricane/cyclones/typhoons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Co-incidences in nature occur all the time.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2017-09-09T12:43:42.623" LastActivityDate="2017-09-09T12:43:42.623" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12264" PostTypeId="1" CreationDate="2017-09-09T12:39:47.150" Score="1" ViewCount="367" Body="&lt;p&gt;Could the recent 8.1 Magnitude Earthquake at the Cocos and Nazca plates off the Mexican coast have a knock on effect to the Pacific and Juan de Fuca Plates further north at the San Andreas Fault Line?&lt;/p&gt;&#xA;" OwnerUserId="7924" LastActivityDate="2017-09-09T12:39:47.150" Title="Effects of Mexican Earthquake in San Andreas Fault Line" Tags="|earthquakes|seismology|plate-tectonics|seismic|seismic-hazards|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12265" PostTypeId="1" AcceptedAnswerId="12266" CreationDate="2017-09-09T14:11:31.717" Score="6" ViewCount="166" Body="&lt;p&gt;I was wondering if we could possibly reduce the severity of, or steer a hurricane by changing albedo (e.g. dying the part ocean with a temporary light colored dye)?  My thought would be to put this dye well in front of the path of a hurricane, with enough time to reflect the sunlight back off the ocean and cool the ocean surface.  When the hurricane arrives there, the ocean surface should then be cooler, leading to the hurricane being less powerful.  I am also wondering if this could be used to steer the hurricane somehow (e.g. if a hurricane would be drawn to or repelled away from cool ocean surface).  If so, could we use that to steer a hurricane away from populated areas?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Some potential methods (there may be others):&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Use light colored dye injected into the ocean&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Use light colored smoke to block the sun from reaching the ocean&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Possibly use &quot;cloud seeding&quot; ahead of the hurricane and form clouds to block the sun light from warming the ocean. - Covered in the alternate question&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Perhaps a &quot;surface film&quot; could also be applied temporarily to part of the ocean (sort of like a &quot;light colored oil spill&quot;, hopefully with something safer for the environment than oil). - Covered in the alternate question&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;If this experiment were to be conducted, I would think it should be done far from inhabited land.  Environmental impacts would need to be thought out too, e.g. would a film block the carbon dioxide / oxygen exchange in that area and cause severe environmental impact?  Could the experiment actually strengthen instead of weaken a hurricane?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The linked question and answer addresses some, but not all the methods I propose here.  It also proposes some other methods, definitely an interesting read!&lt;/p&gt;&#xA;" OwnerUserId="11017" LastEditorUserId="11017" LastEditDate="2017-09-13T00:43:11.610" LastActivityDate="2023-08-10T01:11:24.930" Title="Could we cool the ocean by reflecting away sunlight to influence hurricanes?" Tags="|meteorology|tropical-cyclone|solar-terrestrial-physics|geoengineering|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12266" PostTypeId="2" ParentId="12265" CreationDate="2017-09-09T16:03:53.737" Score="5" Body="&lt;p&gt;Water has a large &lt;a href=&quot;https://water.usgs.gov/edu/heat-capacity.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;thermal capacity&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;which is why the temperature change between seasons is gradual rather than sudden, especially near the oceans.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;For water to lose heat time is required. By changing the albedo of the ocean just prior to a hurricane/cyclone/typhoon passing over a section of water will not give the water enough time to cool down to have any significant effect.&lt;/p&gt;&#xA;&lt;p&gt;If it were possible to change the temperature of water to minimize the strength of hurricanes/typhoons/cyclones, large sections of ocean would need to have their albedos changed for a long period of time.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Edit 10 August 2023&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.abc.net.au/news/2023-08-10/cyclone-risks-of-controlling-weather-hurricane-typhoon/102706094&quot; rel=&quot;nofollow noreferrer&quot;&gt;Newly discovered information&lt;/a&gt; reveals that hurricanes could be influence by other means - cooling the surface reaches of a region on ocean by pumping cold water from at least 200 m below the ocean surface.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;there's been renewed interest in Cold War era experiments in weather control. While early efforts had little success, our new research evaluates other methods of weakening these storms by pumping up cold water from the depths or spreading particles in the lower atmosphere to reduce incoming heat and encourage early rainfall.&lt;/p&gt;&#xA;&lt;p&gt;In the 1960s, the United States explored the use of cloud seeding to stop hurricanes from forming.&lt;/p&gt;&#xA;&lt;p&gt;During Project STORMFURY, planes flew high above cyclones out at sea and sprayed them with silver iodide, a chemical which could encourage water droplets to clump together and fall as rain. This, the theory ran, would disrupt the hurricane from forming. While some seedings seemed to correlate with weaker hurricanes, the link was never adequately found and the project was eventually abandoned.&lt;/p&gt;&#xA;&lt;p&gt;Instead, researchers are exploring two new options.&lt;/p&gt;&#xA;&lt;p&gt;Cyclones need hot sea surfaces to form. If we could cool the surface – such as by piping chilled water from depths below 200 metres – we could prevent the cyclone from ever forming.&lt;/p&gt;&#xA;&lt;p&gt;The problem is it's expensive. Norwegian cyclone-busting startup OceanTherm estimates it would cost about AUD750 million to develop the technology, and another AUD105 million every year to keep it going.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;And worse, cooling one area of the sea does nothing to stop cyclones from forming elsewhere. Models suggest ocean cooling will, at best, have only a limited dampening effect on cyclones.&lt;/p&gt;&#xA;&lt;p&gt;There's a more likely option – aerosol injection. Scientists already know that dust blown from the Sahara into the Atlantic reduces cyclone formation. We could use planes or drones to inject hygroscopic (water-attracting) particles into the lower atmosphere, where they would reflect and scatter sunlight and trigger rainfall and energy release.&lt;/p&gt;&#xA;&lt;p&gt;This method has a stronger scientific pedigree, given it already occurs naturally. But we don't know what side-effects it would have and we still aren't sure what happens to energy redistributed by the intervention.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2023-08-10T01:11:24.930" LastActivityDate="2023-08-10T01:11:24.930" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="12269" PostTypeId="2" ParentId="12261" CreationDate="2017-09-09T19:45:04.180" Score="1" Body="&lt;p&gt;There is precedent for believing that an extreme weather event can trigger seismic activity. There's also solid evidence linking tidal forces (lunar/solar cycles) to plate boundary slip.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's totally reasonable to think that accumulated repeated tiny stresses, particularly on our dynamic planet, can contribute to the final straw that releases a large seismic event. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So... to answer the OP,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is there substance to her hypothesis / theory, that the Eclipse and recent events on Earth are interrelated?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The answer is, &quot;maybe&quot;. It'll take a couple of graduate-student-years before all of the necessary data is processed, analyzed, argued-over, re-analyzed, submitted, reviewed, edited, and published. If you're interested here's a few papers that your wife will find relevant and fascinating. I also urge you to look over the references at the end of each paper to see how much work has been done in this field by people unwilling to brush off observation as mere coincidence. The first article is a useful starting point:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.theatlantic.com/science/archive/2016/09/moon-tide-earthquakes/499637/&quot; rel=&quot;nofollow noreferrer&quot;&gt;More Evidence That the Moon Contributes to Earthquakes&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Ide and colleagues noticed the Dec. 26, 2004 Sumatran earthquake, most notable for its horrendous, deadly tsunami, occurred near the time of full moon and spring tide. So did the Feb. 27, 2010 temblor in Maule, Chile. These quakes both happened close to the peak of tidal stress, when the moon and sun teamed up to exert the greatest gravitational influence over Earth.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/ngeo/journal/v3/n9/full/ngeo940.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;An integrated perspective of the continuum between earthquakes and slow-slip phenomena&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We find that slow-slip phenomena are not unique to the depths (tens of kilometres) of subduction zone plate interfaces. They occur on faults in many settings, at numerous scales and owing to various loading processes, including landslides and glaciers. Taken together, the observations indicate that slowly slipping fault surfaces relax most of the accrued stresses through aseismic slip.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2010JB007502/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tidal modulation of slow slip in Cascadia&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We find modulation of the strain rate with a 12.4 h period, that of the tide with the largest amplitude, that is significant at the 99% level. The amplitude of this modulation suggests that the slip rate during slow slip events oscillates, on average, 25% above and below its mean value during a tidal cycle.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2008JB006038/pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Correlation of tremor activity with tidal stress in the northern&#xA;Cascadia subduction zone&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Tremor activity during five consecutive ETS events beneath southern and central Vancouver Island correlates significantly better with tidal shear stress and compressive normal stress on shallow dipping surfaces than with tidal confining stress.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/nature/journal/v459/n7248/full/nature08042.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Slow earthquakes triggered by typhoons&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Here we show that, in eastern Taiwan, slow earthquakes can be triggered by typhoons. We model the largest of these earthquakes as repeated episodes of slow slip on a reverse fault just under land and dipping to the west; the characteristics of all events are sufficiently similar that they can be modelled with minor variations of the model parameters. Lower pressure results in a very small unclamping of the fault that must be close to the failure condition for the typhoon to act as a trigger.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7333" LastEditorUserId="20" LastEditDate="2017-09-22T00:38:31.203" LastActivityDate="2017-09-22T00:38:31.203" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12271" PostTypeId="1" CreationDate="2017-09-09T22:38:34.017" Score="2" ViewCount="93" Body="&lt;p&gt;I'm referring to an &lt;a href=&quot;https://arstechnica.com/science/2017/09/us-forecast-models-have-been-pretty-terrible-during-hurricane-irma/&quot; rel=&quot;nofollow noreferrer&quot;&gt;article&lt;/a&gt; I've read on Ars Technica about the differences in various weather models.&lt;br&gt;&#xA;One thing that stood out for me was a mention of  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Forecast models typically show their skill with three-, four-, and five-day forecasts. For simplicity's sake, we will focus on 120-hour forecasts. At this lead time, the average error of the European model with respect to Irma has been about 175km in its position forecast. The next best forecast is from the hurricane center, which is slightly more than 300km. An automated model, then, has so far beaten human forecasters at the National Hurricane Center (looking at all of this model data) by a wide margin.  &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A similar thing about models beating human forecasters was also mention in another article linked in this article and nowhere is there any other explanation for it, so:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Do humans seriously forecast extreme weather?&lt;/strong&gt;&lt;br&gt;&#xA;I get it, that meoteorologists get trained in physics, hydrodynamics etc, but I can't believe that humans try to compete with computers in crunching the numbers on differential equations. Or how else does 'human forecasting' work?&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2017-09-10T14:01:06.030" Title="Human hurricane forecasting?" Tags="|weather-forecasting|tropical-cyclone|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="12272" PostTypeId="2" ParentId="12262" CreationDate="2017-09-10T00:46:12.630" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;In particular, in season 7 of Game of Thrones, the island of Dragonstone is revealed to contain a veritable mountain of obsidian - is such a thing possible in the real world? I would have thought that, above a certain volume, the center of the mass would be well-enough insulated so that crystallization could occur, spoiling the obsidian.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Sure, an island of obsidian could form as result of repeated felsic eruptions depositing layer upon layer of obsidian. But, it'd be a relatively recent eruption as obsidian is mineralogically unstable and devitrifies into crystalline chrystobalite, as it slowly, ever so slowly becomes quartz.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2017-09-10T00:46:12.630" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12273" PostTypeId="1" AcceptedAnswerId="12303" CreationDate="2017-09-10T03:17:24.123" Score="6" ViewCount="216" Body="&lt;p&gt;The Washington Post article &lt;a href=&quot;https://www.washingtonpost.com/news/capital-weather-gang/wp/2017/09/09/hurricane-irma-is-literally-sucking-the-water-away-from-shorelines/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hurricane Irma is literally sucking the water away from shorelines&lt;/a&gt; written by the Post's atmospheric scientist Angela Fritz describes leads with this:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;As a meteorologist, there are things you learn in textbooks that you may never see in person. You know they happen theoretically, but the chances of seeing the most extraordinary weather phenomena are slim to none.&lt;/p&gt;&#xA;&lt;p&gt;This is one of those things — a hurricane strong enough to change the shape of an ocean.&lt;/p&gt;&#xA;&lt;p&gt;[...](links to images in social media)&lt;/p&gt;&#xA;&lt;p&gt;Basically, Hurricane Irma is so strong and its pressure is so low, it’s sucking water from its surroundings into the core of the storm.&lt;/p&gt;&#xA;&lt;p&gt;The wind on Long Island in the Bahamas is from the southeast to the northwest on Saturday. On the northwest side of the island, it would be blowing the water away from the shoreline.&lt;/p&gt;&#xA;&lt;p&gt;It also may be experiencing the effects of what I call the hurricane “bulge.” In the center of the storm, where there is extreme low pressure, water is drawn upward. Low pressure is basically a sucking mechanism — it sucks the air into it, and when it’s really low, it can change the shape of the surface of the ocean. As the storm draws water toward the center, it gets pulled away from the surroundings&lt;/p&gt;&#xA;&lt;p&gt;In any case, this isn’t the sign of a tsunami. The water will return to Long Island, and it probably won’t rush back with any great force. It will probably be back by Sunday afternoon.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This explanation is confusing me because it seems to suggest that the water level has dropped due to the wind from the southeast, as well as due to the low pressure, which is &amp;quot;basically a sucking mechanism — it sucks the air into it, and when it’s really low, it can change the shape of the surface of the ocean.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Can strong winds ever lower ocean surface heights significantly directly, or are these drops caused by local static pressure differences independent of the wind. Of course pressure and wind are intimately connected, but each should have its own effect on ocean surface height.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;ancillary question:&lt;/em&gt; Since the stated wind direction is &lt;em&gt;essentially parallel to the long direction of the island&lt;/em&gt;, I don't understand why it would preferentially remove water from one side of the island over the other side. Does this make sense?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; &amp;quot;Sea gone dry&amp;quot; from &lt;a href=&quot;https://twitter.com/deejayeasya/status/906327303646580736&quot; rel=&quot;nofollow noreferrer&quot;&gt;this tweet&lt;/a&gt; linked in the Washington Post article.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4YDz5.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4YDz5.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; From Google Maps, marker is on Long Island, Bahamas. 23.16N, 75.08W.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/03aKg.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/03aKg.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-04-02T19:57:36.480" Title="Can strong winds significantly lower ocean surface levels, or is it really the static pressure differences?" Tags="|ocean|tropical-cyclone|barometric-pressure|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12274" PostTypeId="2" ParentId="12239" CreationDate="2017-09-10T09:17:17.790" Score="2" Body="&lt;h2&gt;It &lt;em&gt;might&lt;/em&gt; be possible but hasn't been done in practice&lt;/h2&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.newscientist.com/article/dn14988-invention-hurricane-pacifier/&quot; rel=&quot;nofollow noreferrer&quot;&gt;One idea&lt;/a&gt; is that &lt;strong&gt;smoke could be introduced into the hurricane&lt;/strong&gt; and, because the smoke is heavier than air, the &lt;strong&gt;wind speeds could be reduced&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The smoke would also cause &lt;strong&gt;water vapour to condense at lower altitudes&lt;/strong&gt; and hamper &lt;a href=&quot;https://www.pbslearningmedia.org/resource/nves.sci.earth.hurricane/water-vapor-fuels-hurricanes/&quot; rel=&quot;nofollow noreferrer&quot;&gt;the heat cycle&lt;/a&gt; within a hurricane. &lt;strong&gt;When the water evaporates it carries with it the energy&lt;/strong&gt; needed to heat it to that point. The water vapour is lighter than air and will rise but once it condenses it falls - releasing the energy it gained from rising (like if you pushed a ball up a hill), this energy adds to the air currents within the hurricane. If the water condenses at a lower altitude it doesn't have as much energy.&lt;/p&gt;&#xA;&lt;p&gt;There are other ideas such as &lt;a href=&quot;https://usatoday30.usatoday.com/weather/research/2009-07-15-gates-hurricanes_N.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;using fans to blow in cool air&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Project_Stormfury&quot; rel=&quot;nofollow noreferrer&quot;&gt;seeding clouds with silver iodide&lt;/a&gt; (link makes for an interesting read but ultimately failed), these ideas may also have some potential but one of the problems with altering complex weather systems is that the side effects are not necessarily well understood. This makes carrying out practical tests difficult on both a moral and &lt;a href=&quot;https://en.wikipedia.org/wiki/Project_Stormfury#Project_Cirrus&quot; rel=&quot;nofollow noreferrer&quot;&gt;legal level&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11026" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-09-13T09:35:18.870" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12275" PostTypeId="2" ParentId="9720" CreationDate="2017-09-10T09:55:42.177" Score="3" Body="&lt;p&gt;Plate movements can be detected with GPS, as this short outreach document made by US earthquake researchers explains: &lt;a href=&quot;http://www.iris.edu/hq/files/programs/education_and_outreach/aotm/14/1.GPS_Background.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.iris.edu/hq/files/programs/education_and_outreach/aotm/14/1.GPS_Background.pdf&lt;/a&gt; .&#xA;Measurement accuracies of GPS and geodetic technologies get better all the time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Central to the theory of Plate Tectonics are &lt;a href=&quot;https://en.wikipedia.org/wiki/Subduction&quot; rel=&quot;nofollow noreferrer&quot;&gt;Subduction&lt;/a&gt; processes, which are also the subject of much current research.&#xA;For instance accurately characterizing deep earthquakes, in particular those occuring in Subduction Zones along the &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Ring_of_Fire&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ring of Fire&lt;/a&gt;&quot; around the Pacific gives us evidence for Subduction Processes and therefore Plate Tectonics. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Numerical modeling of the Earth as a giant sphere, or nested set of spheres, combined with experimental data (rock melting experiments, high-pressure experiments) show that Plate Tectonics is possible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also we have more evidence from radiogenic dating of Oceanic crust. Most of the rocks on the seafloor are much younger than continental crust. The youngest are at &lt;a href=&quot;https://en.wikipedia.org/wiki/Mid-ocean_ridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mid-Oceanic Ridges&lt;/a&gt;, where submarine volcanism and deeper volcanic processes drive Plate Tectonics (together with Subduction - now, since the mid-seventies, interpreted as a &quot;recycling process&quot; of ocean crust)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Observing other celestial bodies show that similar processes are occuring in the Solar system. &lt;a href=&quot;https://www.jpl.nasa.gov/news/news.php?release=2014-300&quot; rel=&quot;nofollow noreferrer&quot;&gt;Jupiter's Moon Europa&lt;/a&gt;  and Saturn's Moon Enceladus for instance, seem to have huge &lt;a href=&quot;https://en.wikipedia.org/wiki/Tiger_stripes_(Enceladus)&quot; rel=&quot;nofollow noreferrer&quot;&gt;cracks/gaps&lt;/a&gt; in their crust/surfaces. (This is of course also subject of much research). &lt;/p&gt;&#xA;" OwnerUserId="10856" LastActivityDate="2017-09-10T09:55:42.177" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12276" PostTypeId="2" ParentId="12262" CreationDate="2017-09-10T10:07:19.490" Score="3" Body="&lt;p&gt;&lt;strong&gt;Q1&lt;/strong&gt;: A volcano consists of many lava flows that occur over a long period of time.&#xA;In general, only very few of these lava flows have the right composition and  the right cooling history that are required to form obsidian.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is why only parts of a volcano consist of obsidian, and by volume it's a generally a very small amount.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Q2&lt;/strong&gt;: And yes there is &lt;strong&gt;amorphous ice&lt;/strong&gt;. It is known &lt;a href=&quot;https://scholar.google.de/scholar?q=%22amorphous+ice%22&amp;amp;btnG=&amp;amp;hl=en&amp;amp;as_sdt=0%2C5&amp;amp;as_vis=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;since the 1980s&lt;/a&gt;. These days it is being used in laboratory environments, e.g. for electron cryomicroscopy. This is a high-tech-method for observing biochemical reactions and cellular processes in situ. The microorganisms need to be alive and in the middle of a reaction when shock-freezed. Researchers want to image atomic structures of the biomolecules, not from ubiquitous crystalline water so it better be amourphous.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Q3&lt;/strong&gt;: Glass from windows and bottles contains more Na and K than most Granitic rocks. Na- and K-rich ingredients are being added as fluxing agent (limestone, soda), in the glass factory, decreasing the melting point of the silicates and therefore lowering the production costs.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think a melt of bottle glass, when crystallizing slowly would initially form the minerals Nepheline and Leucite, but late in the solidifcation process also Alkali Feldspar, and some Quarz, among other minerals. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you cooled it so slowly that no glass phase forms, you still might get zoned crystals, having with a different composition from core to rim. That depends on the absence/presence of impurities and local chemical (dis-) equilibria.&lt;/p&gt;&#xA;" OwnerUserId="10856" LastEditorUserId="10856" LastEditDate="2017-09-11T07:29:33.857" LastActivityDate="2017-09-11T07:29:33.857" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12278" PostTypeId="2" ParentId="12271" CreationDate="2017-09-10T14:01:06.030" Score="2" Body="&lt;p&gt;The forecasts issued by the National Hurricane Center are made by people. Those people use every single tool they have at hand. This includes forecasts made by automated tools such as the European Centre for Medium-Range Weather Forecasts (the &quot;European model&quot;). It also includes forecasts made by several other models. The human-generated forecasts account for the skills of those various models, for the ages of the forecasts made by those models, and for data that are not used by those models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When multiple models more or less agree, the human forecasters use techniques and their judgement to split the difference. There is no splitting the difference when models disagree massively, as currently is the case with Jose. The current forecast (advisory 20A at 0800 AST on 10 September 2017), depicted graphically below, appears to be exactly that made by the ECMRWF.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vyfo6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vyfo6.png&quot; alt=&quot;Forecast for Hurricane Jose, issued 10 September 2017 at 0800 AST. In this forecast, Jose starts heading away from land but makes a loop and starts heading back toward land near the end of the week.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-09-10T14:01:06.030" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12280" PostTypeId="1" CreationDate="2017-09-11T01:34:47.287" Score="4" ViewCount="4345" Body="&lt;p&gt;Is carbon lost from topsoil when it's degraded/removed? What is the scientific process?&lt;/p&gt;&#xA;" OwnerUserId="11031" LastActivityDate="2017-10-12T21:31:04.197" Title="Soil Science and the carbon cycle - is carbon released from soil into the atmosphere?" Tags="|soil|soil-science|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12282" PostTypeId="2" ParentId="12280" CreationDate="2017-09-11T10:52:59.960" Score="2" Body="&lt;p&gt;There are two ways carbon is released from soil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first is cellular respiration of plants that uses previously stored energy (visualized in this &lt;a href=&quot;https://en.wikipedia.org/wiki/Cellular_respiration#/media/File:CellRespiration.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;chart&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second is when heterotrophs consume organic carbon below ground and respire carbon dioxide.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sum of these is called soil respiration, which I think was the process you were asking about.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastActivityDate="2017-09-11T10:52:59.960" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12283" PostTypeId="1" AcceptedAnswerId="12287" CreationDate="2017-09-11T17:30:04.327" Score="12" ViewCount="7888" Body="&lt;p&gt;I noticed that temperature drops in the surrounding area of a hurricane. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Is the heat converted into kinetic energy?&lt;/li&gt;&#xA;&lt;li&gt;Could the shape of the hurricanes reflect sunlight?&lt;/li&gt;&#xA;&lt;li&gt;Do they create more lightning in an area that would normally have lower levels of lightning for the same timeframe, in turn creating more ozone?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2019-06-04T16:14:36.747" LastActivityDate="2019-10-11T09:09:19.157" Title="Do hurricanes cool the earth?" Tags="|temperature|wind|tropical-cyclone|ozone|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="12287" PostTypeId="2" ParentId="12283" CreationDate="2017-09-12T03:58:23.403" Score="12" Body="&lt;p&gt;Hurricanes can be viewed as having primary and secondary circulations. The primary circulation is what we see in satellite photos, comprising the winds and clouds that circle the low pressure zone at the center of the hurricane. The secondary circulation is a vast heat engine that provides the energy needed to sustain the primary circulation.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The low pressure cell at the center draws surface air toward the center, gathering moisture from the warm ocean along the way. This flow is more or less isothermal.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Humid air rises in the clouds around the center of the storm, releasing moisture along the way. This rise is more or less adiabatic.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The now dry air at the top of the troposphere flows outward and radiates energy into space. This flow is roughly isothermal.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Finally, the air falls in downdrafts at the outer edges of the storm. Like the updrafts near the eye wall, the flow in these downdrafts is more or less adiabatic. From here the cycle repeats.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;This heat engine, powered by a hundred kelvin temperature difference between the warm oceans and the top of the troposphere, does a very nice job of locally cooling the Earth.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-09-12T03:58:23.403" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12288" PostTypeId="1" CreationDate="2017-09-12T11:04:17.763" Score="1" ViewCount="87" Body="&lt;p&gt;I have been recently studying about the layers of the earth and I got stuck with the question that why is the inner core of the Earth solid in spite of being the deepest and the hottest layer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope I could gather your support and help other students as well.&lt;/p&gt;&#xA;" OwnerUserId="11042" LastEditorUserId="2536" LastEditDate="2017-09-12T12:08:38.497" LastActivityDate="2017-09-12T12:08:38.497" Title="Why is the Inner Core of the Earth solid in spite of being the deepest and the hottest layer of the Earth" Tags="|geophysics|core|" AnswerCount="0" CommentCount="1" ClosedDate="2017-09-12T18:12:00.207" ContentLicense="CC BY-SA 3.0" />
  <row Id="12291" PostTypeId="1" CreationDate="2017-09-12T20:17:15.107" Score="4" ViewCount="889" Body="&lt;p&gt;Any time I hear the word &quot;plateau&quot;, I usually associate it with the tallest in the world, Tibet.  Anyone who looks closely at a map will see that the southern line of the plateau parallels the location and length of the Himalayas, leading to the assumption that the collision between India and mainland Asia, which resulted in the formation of the Himalayas, also forced Tibet upwards, creating the highest great plain on Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.pmfias.com/wp-content/uploads/2015/12/Major-plateaus-of-the-World-upsc-ias.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;But as the link here shows, it's not so simple.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Altiplano is classified as a plateau, yet it does not span the entire length of the entire Andes, the longest mountain range in the world.  Nor does the Colorado parallel the whole length of the Rockies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if a plateau is not formed as originally lowlands forced upwards by nearby mountain-building, then how does it REALLY form?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastEditorUserId="725" LastEditDate="2018-09-04T23:49:38.753" LastActivityDate="2023-12-06T20:18:53.750" Title="How Do Plateaus Really Form?" Tags="|plate-tectonics|mountains|tibetan-plateau|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="12294" PostTypeId="2" ParentId="12242" CreationDate="2017-09-12T22:20:21.790" Score="3" Body="&lt;p&gt;This is going to be brief as on a phone : I welcome somebody posting a more complete answer. But the basic principle of large waves appearing from wind is: &#xA; from a smooth water surface, the wind can produce only small ripples. But those ripples mean that the surface is no longer smooth. The higher the ripples get, the more surface there is for the wind to act upon, thus enlarging them more. Thus are local wind waves formed. For these wind waves to build into the large swell that is found in the oceans, this process needs to continue for a number of days, and some hundreds or thousands of miles. Large swell waves hitting the coast may have been formed in a storm the other side of an ocean. &lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2017-09-12T22:20:21.790" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12295" PostTypeId="2" ParentId="12258" CreationDate="2017-09-12T22:56:38.120" Score="0" Body="&lt;p&gt;The winds are at a maximum velocity Vmax in they eye wall, a thin annulus immediately around the eye. With increasing distance the winds fall off. If a hurricane was a Rankine vortex, the wind velocity at radius R from the center of the eye would be V(R) = Vmax X (Reye/R), where Reye is the radius of the eye. In reality friction usually prevents a hurricane from being a perfect Rankine vortex. Instead it typically a modified Rankine vortex, with V(R) = Vmax X (Reye/R)^n, where n is typically in the range 1/2 &amp;lt; n &amp;lt; 3/4 (perhaps n = 2/3 is the best overall average value). Of course this is a radially-smoothed-out wind velocity distribution. In the approach of an actual hurricane, wind does not increase monotonically as R decreases. But V(R) = Vmax X (Reye/R)^2/3 typically approximates the secular trend of its increase.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-09-12T22:56:38.120" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12296" PostTypeId="2" ParentId="12257" CreationDate="2017-09-12T23:35:17.827" Score="1" Body="&lt;p&gt;This perhaps only indirectly addresses the question, but maybe it might be helpful. According to Kerry Emmanuel's book &quot;Divine Wind&quot;, a hurricane can, in a sense, achieve super-Carnot efficiency without violating the Second Law of Thermodynamics. A hurricane's heat reservoir is the ocean surface at temperature Th and its cold reservoir is the tropopause at temperature Tc. Heat flow Q, mainly via water evaporating from the warm ocean and condensing in the cold upper troposphere is, according to the Carnot efficiency (Th - Tc)/Th, converted into work W as per W = Q(Th - Tc)/Th. But a hurricane's work output is the kinetic energy generation for its winds. With a hurricane in steady sate (constant wind speeds) kinetic energy generation is matched by frictional dissipation. Frictional dissipation of W into the hot reservoir reduces the net heat input required from the hot reservoir from Qh to Qh - W = Qc and raises the hurricane's efficiency to (Th - Tc)/Th X Qh/(Qh - W) = (Th - Tc)/Th X Qh/Qc = (Th - Tc)/Th X Th/Tc = (Th - Tc)/Tc. The Second Law of Thermodynamics is not violated because it allows work to be dissipated via friction as heat at any temperature --- at Th as well as at Tc. Of course the above assumes perfect or reversible operation. Like all real heat engines, hurricanes are imperfect. But perhaps it at least illustrates the point.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-09-12T23:35:17.827" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12297" PostTypeId="1" CreationDate="2017-09-13T05:53:31.140" Score="4" ViewCount="656" Body="&lt;p&gt;Solar storms have a direct effect on Earth, creating charged particles.  What are the direct and indirect effects of large solar storms on Earth's atmosphere?  Do solar storms affect Earth's weather?&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2019-02-06T18:43:38.017" Title="Do solar storms affect Earth's weather?" Tags="|meteorology|atmosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12298" PostTypeId="1" AcceptedAnswerId="12300" CreationDate="2017-09-13T06:00:16.020" Score="4" ViewCount="309" Body="&lt;p&gt;While keeping a close eye on typhoon Talim, I noticed that tropical storm Doksuri is also on the map and has caused serious damage and loss of life. I had thought that the naming of tropical storms is alphabetical (within a given area) so it seems that Doksuri with a &quot;D&quot; must be quite old by now, and Talim fairly young.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do I have the basic idea correct? I've tried to read the Wikipedia article &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_cyclone_naming#Eastern_Pacific_Ocean&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tropical cyclone naming&lt;/a&gt; but it gets a little complicated to read as it start to break things down by East Pacific and West Pacific and I am not sure from where these two originated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How did a &quot;D&quot; and a &quot;T&quot; end up so close together? Is this unusual?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; Screen shot from the Taiwan Central Weather Bureau's &lt;a href=&quot;http://www.cwb.gov.tw/V7e/prevent/typhoon/ty.htm?&quot; rel=&quot;nofollow noreferrer&quot;&gt;Typhoon News&lt;/a&gt; page.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zZfH9.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zZfH9.jpg&quot; alt=&quot;Typhoon Talim and Tropical Storm Doksuri&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2017-09-13T12:09:27.023" Title="How did a tropical storm starting with &quot;D&quot; end up next to a typhoon starting with &quot;T&quot;?" Tags="|tropical-cyclone|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12300" PostTypeId="2" ParentId="12298" CreationDate="2017-09-13T09:03:30.853" Score="7" Body="&lt;p&gt;The naming of typhoons, in the north west pacific region, is different to that used by other parts of the world. According to &lt;a href=&quot;https://www.accuweather.com/en/weather-news/typhoons-how-are-they-named-pacific/32987163&quot; rel=&quot;noreferrer&quot;&gt;accuweather&lt;/a&gt;,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;For typhoons, there is one list with 140 names submitted from nations in the region such as China, Japan, Vietnam and Cambodia. There is no restrictions to how many can be used in a calendar year.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;“Unlike hurricanes, lists are not year-specific, so they scroll through the whole list irrespective of calendar&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The Philippines are also a part of the list of nations which submit names. However, according to the Philippine Atmospheric, Geophysical and Astronomical Services Administration (PAGASA), they will use local names whenever a cyclone is within the Philippine Area of Responsibility (PAR). &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.prh.noaa.gov/cphc/pages/names.php&quot; rel=&quot;noreferrer&quot;&gt;NOAA&lt;/a&gt; has a list of the names for the north west pacific region. At the end of the webpage, in column V of the last table you will see Talim followed by Doksuri, then Khanun. This is why you are seeing Tropical Storm Doksuri just after Tropical Storm Talim.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SK2bp.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SK2bp.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It appears that &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_Storm_Doksuri&quot; rel=&quot;noreferrer&quot;&gt;Doksuri&lt;/a&gt;, which means eagle, Korean, is the replacement name for Nabi. South Korea submitted the name Nabli to the list of typhoon names, but the name Nabi was retired when Typhoon Nabi hit Japan in 2005.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tropical Storm Doksuri (2017) was initially named &lt;a href=&quot;https://pubfiles.pagasa.dost.gov.ph/tamss/weather/bulletin2.pdf&quot; rel=&quot;noreferrer&quot;&gt;Maring&lt;/a&gt; by the Philippine authorities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/75rCa.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/75rCa.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2017-09-13T12:09:27.023" LastActivityDate="2017-09-13T12:09:27.023" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12301" PostTypeId="1" CreationDate="2017-09-13T17:00:34.210" Score="4" ViewCount="55" Body="&lt;p&gt;I saw this image in &lt;a href=&quot;https://earthscience.stackexchange.com/a/3171/6031&quot;&gt;this answer&lt;/a&gt; to the question &lt;a href=&quot;https://earthscience.stackexchange.com/q/3114/6031&quot;&gt;Noctilucent clouds and anthropogenic climate change&lt;/a&gt; which was listed as related to the question &lt;a href=&quot;https://earthscience.stackexchange.com/q/9960/6031&quot;&gt;“New” cloud types: Can they be used as markers for climate change observations?&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In recent observations, reported in the NASA article &lt;a href=&quot;http://science.nasa.gov/science-news/science-at-nasa/2014/16apr_teleconnections/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Unexpected teleconnections in noctilucent clouds&lt;/a&gt; in 2014 found that the winter air temperature over the USA and Arctic stratospheric conditions have a direct link to the frequency of NLC over Antarctica (as per the image below from NASA):&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ARJAV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ARJAV.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At first glance I thought it was an illustration of coincidental correlations until I realized that it's &lt;em&gt;arctic&lt;/em&gt; and not &lt;em&gt;antarctic&lt;/em&gt; and so they are in the same hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; But I'm curious, was this still a one-off 45 day coincidental correlation, or has this happened again in 2015 and 2016?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2022-04-29T01:53:47.717" LastActivityDate="2022-04-29T01:53:47.717" Title="Do surface temperatures at lower latitudes continue to correlate with frequency of noctilucent clouds in the arctic stratosphere?" Tags="|climate-change|climate|clouds|weatherdata|anthropocene|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12302" PostTypeId="1" AcceptedAnswerId="12306" CreationDate="2017-09-14T01:49:31.717" Score="2" ViewCount="55" Body="&lt;p&gt;I'm new to climate science - starting to get familiar with the field by reading some published articles. Terminology is always hard when starting into a new domain. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this paper, &lt;a href=&quot;http://www.cgd.ucar.edu/cas/adai/papers/Dai-NatureClimChange-final.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dai - Increasing drought under global warming in observations and models&lt;/a&gt;, what does the author mean by the term &quot;forcing,&quot; in relation to the PDSI?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is an example of usage: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The PDSI is calculated from a water-balance model forced with observed&#xA;  precipitation and temperature...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Another example: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Figure 1a,b shows that the broad patterns of the linear trends from&#xA;  1950 to 2010 in observed annual precipitation and calculated&#xA;  sc_PDSI_pm using observation-based forcing2&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Here is the citation: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Dai, Aiguo. &quot;Increasing drought under global warming in observations&#xA;  and models.&quot; Nature Climate Change 3, no. 1 (2013): 52-58.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="11050" LastEditorUserId="11050" LastEditDate="2017-09-14T13:09:49.473" LastActivityDate="2017-09-14T13:09:49.473" Title="'Forcing' in PDSI Calculation" Tags="|climate-change|drought|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12303" PostTypeId="2" ParentId="12273" CreationDate="2017-09-14T03:09:29.907" Score="3" Body="&lt;p&gt;The explanation for the wind effect on water level at the coast is basically the same as for &lt;a href=&quot;https://en.wikipedia.org/wiki/Upwelling&quot; rel=&quot;nofollow noreferrer&quot;&gt;upwelling circulation&lt;/a&gt;. In an upwelling situation, the winds flow parallel to the coast and generate upwelling dynamics: surface Ekman balance is setup (in deep enough waters) with water transport being to the right (left) of the wind in the northern (southern) hemisphere; this causes a deficit along the coast that needs a compensating flow in the deeper part of the water column bringing cold water to the surface. The deficit along the coast and the resulting sloping density levels create a &lt;a href=&quot;https://en.wikipedia.org/wiki/Geostrophic_current&quot; rel=&quot;nofollow noreferrer&quot;&gt;geostrophic&lt;/a&gt; balance and that causes the surface water level to drop near the coast (wind set-down).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good diagram of the processes at play is available from Csanady (1981). &lt;a href=&quot;https://i.stack.imgur.com/qH9Ap.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qH9Ap.png&quot; alt=&quot;Csanady EOS&quot;&gt;&lt;/a&gt;&#xA;Source: &lt;a href=&quot;http://dx.doi.org/10.1029/EO062i002p00009&quot; rel=&quot;nofollow noreferrer&quot;&gt;EOS&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In reality, the Ekman balance-geostrophic balance combo is a better approximation when the shelf is narrow and there is a stronger connection with the open ocean. In shallower areas, the wind that matter most is not the along-shelf wind, but rather the cross-shelf wind:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/12030/depth-of-the-wind-induced-currents-and-the-shoreline&quot;&gt;Depth of the wind-induced currents and the shoreline&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In the case of a hurricane, the winds and atmospheric effects are so strong that it is difficult to separate the two. The article cited in the question mentions the two effects. The fact that the wind lined up with the coastal alignment suggests that wind set-down might have been a factor. It is not that uncommon for wind set-down to be a controlling process (e.g., &lt;a href=&quot;http://www.science20.com/news_articles/parting_red_sea_could_it_have_happened_wind_setdown_model_says_yes&quot; rel=&quot;nofollow noreferrer&quot;&gt;Red Sea&lt;/a&gt; (&lt;a href=&quot;http://dx.doi.org/10.1175/1520-0477(1992)073%3C0305:ATOEFT%3E2.0.CO;2&quot; rel=&quot;nofollow noreferrer&quot;&gt;also&lt;/a&gt;)).&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Csanady, G. T. (1981). Circulation in the coastal ocean, Part 1. Eos, Transactions American Geophysical Union, 62(2), 9-11.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="111" LastActivityDate="2017-09-14T03:09:29.907" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12305" PostTypeId="1" AcceptedAnswerId="13027" CreationDate="2017-09-14T05:23:59.173" Score="7" ViewCount="8257" Body="&lt;p&gt;What is the difference between a segd recorded data and a segy recorded data and can we convert from segd to segy and vice versa?&lt;/p&gt;&#xA;" OwnerUserId="2662" LastEditorUserId="2662" LastEditDate="2017-09-14T05:38:08.827" LastActivityDate="2021-02-18T17:43:55.203" Title="SEGD and SEGY recorded data" Tags="|geophysics|seismology|seismic|data-formats|field-measurements|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12306" PostTypeId="2" ParentId="12302" CreationDate="2017-09-14T07:32:08.527" Score="1" Body="&lt;h1&gt;What does 'forcing' mean?&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The PDSI is calculated from model output data. Models do not predict all relevant variables but some data need to be provided externally from the user. These externally provided data are denoted as &quot;&lt;em&gt;forcing&lt;/em&gt;&quot; because they &quot;&lt;em&gt;force&lt;/em&gt;&quot; the model &lt;em&gt;to move in one direction&lt;/em&gt; (colloquially speaking). You might also call it &quot;&lt;em&gt;drive&lt;/em&gt;&quot; a model -- but &quot;&lt;em&gt;to force&lt;/em&gt;&quot; is the established expression in science.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;In this case&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;In this particular case, the authors use observational data as input data for the model calculations. Therefore, the authors write&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The PDSI is calculated from a &lt;strong&gt;water-balance model forced with observed precipitation&lt;/strong&gt; and temperature...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;h1&gt;Other situations&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;One might force a model also with data from other models. A river run-off model might get input data from an atmospheric/meteorological model, which predicts precipitation and solar radiation at surface level. We could write&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The river run-off model ABC is &lt;strong&gt;forced&lt;/strong&gt; by modeled precipitation and radiation of the XYZ meteorological model.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2017-09-14T07:32:08.527" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12307" PostTypeId="2" ParentId="9951" CreationDate="2017-09-14T07:46:05.853" Score="1" Body="&lt;p&gt;Please go through the Variable table vtable.ECMWF . Download all the variables in that list. These are the minimum variables required to initiate WRF.  &lt;/p&gt;&#xA;" OwnerUserId="11053" LastEditorUserId="5594" LastEditDate="2017-12-13T22:07:11.507" LastActivityDate="2017-12-13T22:07:11.507" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12308" PostTypeId="1" CreationDate="2017-09-14T18:18:58.067" Score="1" ViewCount="78" Body="&lt;p&gt;In this video from min. 7:00 is after digging in the Earth a fountain created of water. Is this due to the pressure of the water in the Earth, if so how did it get there and how did it get such a high pressure?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=0wdliVXxZEo&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=0wdliVXxZEo&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5372" LastActivityDate="2017-09-14T18:18:58.067" Title="How can this fountain of (hot?) water coming out of the Earth arise?" Tags="|geophysics|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12311" PostTypeId="2" ParentId="12297" CreationDate="2017-09-15T12:44:33.127" Score="1" Body="&lt;p&gt;Those charged particles you mention are not created by any kind of interaction with the Earth, but rather the term solar storm is used to refer to the temporary disturbance of Earth's magnetic field caused by bombardment of the charged particles which originate from the Sun. The stream of particles flow outward from the sun through the solar system(The particles escape from the sun because its outer atmosphere is very hot, and the atoms there move too rapidly for the sun's gravity to hold onto them).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, these charged particles are different to the usual  solar radiation (visible and ultraviolet light) that penetrates Earth’s atmosphere and warms the surface. Most of the charged particles that are aimed at the Earth are deflected back into space by Earth's magnetic field, although a small amount may enter the thermosphere (upper atmosphere). This may cause some warming in the thermosphere, however, carbon dioxide and nitrogen oxide, coolants in the thermosphere, absorb the energy and then re-radiate heat back into space.  A small fraction of the extra heat from the solar flare radiates to layers of the atmosphere below the thermosphere, but it is insignificant compared to the normal amount of heating the lower layers of the atmosphere already experience from normal solar radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bates, D.R., 1969. PHYSICS OF THE UPPER ATMOSPHERE. QUEEN'S UNIV BELFAST (NORTHERN IRELAND) DEPT OF APPLIED MATHEMATICS AND THEORETICAL PHYSICS.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mlynczak, M.G., Martin‐Torres, F.J., Crowley, G., Kratz, D.P., Funke, B., Lu, G., Lopez‐Puertas, M., Russell, J.M., Kozyra, J., Mertens, C. and Sharma, R., 2005. Energy transport in the thermosphere during the solar storms of April 2002. Journal of Geophysical Research: Space Physics, 110(A12).&lt;/p&gt;&#xA;" OwnerUserId="10710" LastActivityDate="2017-09-15T12:44:33.127" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12312" PostTypeId="1" CreationDate="2017-09-15T14:37:02.967" Score="3" ViewCount="26" Body="&lt;p&gt;I am searching for an illustrated naturalist handbook to coastal California vegetation (trees, shrubs, wildflowers) organized by ecosystem. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, there might be sections for coastal dunes (with illustrations and information for beach sagewort, mock Heather, beach primrose, etc), chaparral (chamise, toyon, manzanita, sticky monkey, etc), coastal sage scrub (California sagebrush, coyote brush, sticky monkey), oak woodland, Monterey pine forest, and so forth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Color illustrations would be ideal for easier identification. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone know of a book or set of books/guides that could provide this overview, or at least get close? I would also settle for separate sources of the tree/shrub/flower illustrations and the details of common species by ecosystem. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's often great local signage at state parks providing this sort of information, but I have not been able to locate a comparable reference guide. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many thanks!&lt;/p&gt;&#xA;" OwnerUserId="11061" LastActivityDate="2017-09-15T14:37:02.967" Title="In search of California ecosystem vegetation field guide" Tags="|ecology|resources|vegetation|california|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12313" PostTypeId="2" ParentId="7502" CreationDate="2017-09-15T16:34:38.933" Score="-4" Body="&lt;p&gt;I think you can tell, because you were smart enough to ask the question in the first place, that the answers are not sufficient and ignore the big picture. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is no observed or demonstrated greenhouse gas effect in the real world.  The weight of the atmosphere alone gives an average global temperature at sea level of 288 degrees K, or 14.85 C. This is actually a little warmer than the true global average surface temperature because not all the surface is at sea level.  There is no added heat from the greenhouse effect, and to know why you need to delve into thermodynamics and quantum mechanics.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In theory and shown by experimentation, a dipole molecule can absorb long wave radiation and cause it to vibrate and rotate, adding to its kinetic energy.  However, there are limits on how much energy this long wave radiation can transfer to a molecule; if the molecule already has a certain level of translational kinetic energy, longwave radiation will not excite the molecule further.  Just like you'd never see a 100 degree hot plate heat air above it greater than 100 degrees even as the hotplate continues to emit infrared radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most, err the vast majority, of the kinetic energy in air is derived from collisions of gas molecules with the solar-warmed surface, and from latent heat of water vapor.  Most of this energy is translated throughout the lower atmosphere by molecular collisions and transferred to the upper troposphere by convection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is demonstrated by nature every night in arid regions of the planet.  In deserts, such as the Sahara, the surface temperature quickly rises during the day.  That's because no heat energy is being converted into latent heat by evaporating water, it's all going into kinetic energy which you can feel as temperature.  At night, the surface and the air cool quickly as the heat is convected in air masses vertically and then easily radiate their energy into space with no measurable greenhouse gas warming.  In fact, the Sahara Desert actually loses more energy into space than it receives from the sun on an annual basis.  As counterintuitive as this sounds, it's been measured by satellites that have been operating for over a decade.  The climate of Earth is dominated by water.  The heat capacity and energy transfer mechanics of water in its three phases completely overwhelms any effect from longwave radiation donating electron volts of energy to trace gases in the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://stevengoddard.wordpress.com/2014/01/25/ir-expert-speaks-out-after-40-years-of-silence-its-the-water-vapor-stupid-and-not-the-co2/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://stevengoddard.wordpress.com/2014/01/25/ir-expert-speaks-out-after-40-years-of-silence-its-the-water-vapor-stupid-and-not-the-co2/&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or, you can believe conjecture, arm waving, and major assumptions that lead to claims like that Venus would be a mere -43 degrees F without the &quot;greenhouse&quot; effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://geosci.uchicago.edu/~rtp1/papers/PhysTodayRT2011.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://geosci.uchicago.edu/~rtp1/papers/PhysTodayRT2011.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11062" LastActivityDate="2017-09-15T16:34:38.933" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12317" PostTypeId="2" ParentId="12246" CreationDate="2017-09-16T02:31:54.140" Score="1" Body="&lt;p&gt;I don't think so. A large fire could generate a circulation with strong low-level convergence and upper level divergence that would cause subsidence as the air radiatively cooled. If the fire were stationary and huge, the Coriolis effect could make it's upper level outflow turn, but I don't think an intense hurricane-like cyclone could form unless the fire were actually relatively small (like the eyewall of a hurricane), but in that case I'm not sure that the necessary pressure gradient could be maintained (even if the fire could somehow continue to be fueled). &lt;/p&gt;&#xA;" OwnerUserId="3339" LastEditorUserId="3339" LastEditDate="2017-09-16T18:14:51.387" LastActivityDate="2017-09-16T18:14:51.387" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12319" PostTypeId="1" CreationDate="2017-09-17T02:37:27.187" Score="6" ViewCount="923" Body="&lt;p&gt;There are serious ideas, if not quite yet plans, for space missions to the Moon and Mars to take advantage of in situ resources, such as producing oxygen for propulsion (e.g. for a sample return) out of Mars' atmosphere or from water ice on the Moon. This is of course considered because space flight is expensive per kilogram launched from Earth. There's some similarity with research stations in the Antarctic with fairly expensive logistics. So I wonder if they somehow are living off the land to cut costs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do research stations use the local water, or is even water for showering flown in by airplanes?&lt;/p&gt;&#xA;" OwnerUserId="3033" LastActivityDate="2017-09-19T21:59:24.103" Title="Do Antarctic research stations use any of the local resources, like water, or is everything flown in?" Tags="|antarctic|resources|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12320" PostTypeId="2" ParentId="12319" CreationDate="2017-09-17T03:31:22.300" Score="8" Body="&lt;p&gt;The &lt;a href=&quot;http://www.antarctica.gov.au/about-antarctica/people-in-antarctica/water&quot; rel=&quot;noreferrer&quot;&gt;Australian&lt;/a&gt; and Belgian Antarctic research stations use local resources for their respective water supplies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Australia operates a number of stations. In the past, snow was melted but currently local melt water is processed and used. However, the Australian base, &lt;a href=&quot;https://www.latitude.aq/publications/pdf/ideea1993ag.pdf&quot; rel=&quot;noreferrer&quot;&gt;Casey&lt;/a&gt;, also melts ice and the Mawson base also melts snow.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Getting freshwater in Antarctica is quite difficult and time consuming. The exact method used varies between stations. In earlier days, snow and ice was shovelled into large tanks and heated to form water. Today, Casey and Mawson pump water from a melt lake behind the station and store it in a heated tank house.&#xA;  Davis draws water from a local tarn which is processed by a Reverse Osmosis System which produces about 18,000 litres each 24 hours. The average station demand is around 10,000 – 14,000 litres a day. Macquarie Island draws water from a dam located about three kilometres from the station on the plateau and 200 metres above sea level. The water is pumped to two holding tanks.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Water saving appliances are installed wherever possible, but each person on station is asked to use as little water as possible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Expeditioners are limited to three minute showers and, when water supplies are short, to only shower every second or third day. Other water saving measures are also followed, such as doing one large load of washing rather than several smaller loads, and turning off the taps while cleaning your teeth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Belgian, &lt;a href=&quot;http://www.antarcticstation.org/station/water_treatment/&quot; rel=&quot;noreferrer&quot;&gt;Princess Elisabeth base&lt;/a&gt;, melts snow to obtain water. The Belgians, as do bases from other countries, also use &lt;a href=&quot;http://www.antarcticstation.org/station/renewable_energies/&quot; rel=&quot;noreferrer&quot;&gt;renewable sources&lt;/a&gt; of energy, namely, wind and solar, via wind generators and solar panels. The Australian base at &lt;a href=&quot;http://www.antarctica.gov.au/living-and-working/station-life-and-activities/renewable-energy&quot; rel=&quot;noreferrer&quot;&gt;Mawson has two wind generators&lt;/a&gt; that supply 95 percent of the stations energy requirements&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The US base at Mc Murdo, operated a &lt;a href=&quot;http://large.stanford.edu/courses/2014/ph241/reid2/&quot; rel=&quot;noreferrer&quot;&gt;nuclear reactor&lt;/a&gt; for electricity generation, for 10 years, until 1972. It produce over 78 MWh or electricity and 13 million gallons (49.21 ML) of fresh water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Diesel generators still produce much of the electricity used at Antarctic stations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The French base, Dumont d'Urville, obtains fresh water by &lt;a href=&quot;https://www.latitude.aq/publications/pdf/ideea1993ag.pdf&quot; rel=&quot;noreferrer&quot;&gt;desalinating sea water&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Food is delivered to all the stations from outside because the &lt;a href=&quot;https://www.state.gov/t/avc/trty/193967.htm&quot; rel=&quot;noreferrer&quot;&gt;Antarctic Treaty&lt;/a&gt;, &lt;a href=&quot;http://www.slate.com/blogs/atlas_obscura/2014/10/16/food_in_antarctica_what_explorers_and_researchers_eat.html&quot; rel=&quot;noreferrer&quot;&gt;bans the eating of anything originating from the continent&lt;/a&gt;. This prevents fishing and eating seals or penguins, or any other fauna or flora.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.environments.aq/information-summaries/sources-dispersal-and-impacts-of-wastewater-in-antarctica/&quot; rel=&quot;noreferrer&quot;&gt;Waste water&lt;/a&gt; from bases is treated before being discharged.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mining of minerals and the exploitation of oil and gas from Antarctica is still &lt;a href=&quot;http://www.maritime-executive.com/article/antarctic-mining-ban-reaffirmed&quot; rel=&quot;noreferrer&quot;&gt;banned&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-09-17T03:31:22.300" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12323" PostTypeId="1" CreationDate="2017-09-18T20:05:33.980" Score="0" ViewCount="238" Body="&lt;p&gt;My question is a two part question. First I currently know of two different gradients.I think there is more; however, I don't completely understand what makes a gradient. So, here is my questions.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;What properties can make up a gradient in atmospheric science?&lt;/li&gt;&#xA;&lt;li&gt;What atmospheric gradients are there?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Here are the two I knw about.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Pressure gradient&lt;/li&gt;&#xA;&lt;li&gt;Temperature gradient&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Examples would be nice; however, not necessary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="11084" LastActivityDate="2017-09-19T17:45:42.027" Title="What makes up a gradient" Tags="|meteorology|atmosphere|mathematics|" AnswerCount="3" CommentCount="4" FavoriteCount="0" ClosedDate="2017-09-21T11:57:49.323" ContentLicense="CC BY-SA 3.0" />
  <row Id="12325" PostTypeId="1" AcceptedAnswerId="12327" CreationDate="2017-09-19T00:17:44.700" Score="0" ViewCount="1621" Body="&lt;p&gt;Prevailing winds are generated by Coriolis effects. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think I understand why NE winds are the prevailing winds in 0 to 30 degrees and 60 to 90 degrees latitude in the northern hemisphere (e.g., according to the picture below). But I don't understand why westeries are the prevailing winds in 30 to 60 degrees. If one throws a ball from a point at the equator to the north pole, shouldn't it deflected to the opposite direction by the direction of the rotation of the earth (i.e., creates SE winds)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Fq1cj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Fq1cj.jpg&quot; alt=&quot;Coriolis effect&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11086" LastActivityDate="2017-09-19T05:31:39.050" Title="Prevailing winds between 30 to 60 degrees latitude" Tags="|atmosphere|wind|ecology|" AnswerCount="1" CommentCount="4" ClosedDate="2017-09-19T18:03:37.593" ContentLicense="CC BY-SA 3.0" />
  <row Id="12327" PostTypeId="2" ParentId="12325" CreationDate="2017-09-19T05:31:39.050" Score="-2" Body="&lt;p&gt;Although not 100% sure, after some additional searches, I think the answer is the law of inertia. If one throws a ball from at the equator to the north pole, the ball also moves to the right even if one did not intend to do so. The same effect we see when one throws a ball from a moving car (&lt;a href=&quot;https://www.youtube.com/watch?v=-VJzr_aSSE4&quot; rel=&quot;nofollow noreferrer&quot;&gt;example&lt;/a&gt;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The speed is faster near the equator. Therefore, even through Coriolis effect is working, the law of inertia overrules the effect. That is, the movement (to right) of the ball is faster than the rotation of the earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regardless of from north to south, or south to north, Coriolis effect and the law of inertia work in opposite directions. Stronger one determines the direction.&lt;/p&gt;&#xA;" OwnerUserId="11086" LastActivityDate="2017-09-19T05:31:39.050" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12328" PostTypeId="2" ParentId="12323" CreationDate="2017-09-19T09:05:12.380" Score="1" Body="&lt;p&gt;In addition to other information others have written in comments, gradients measure the rate of change of &quot;a quantity&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, take a hill. As you walk up the hill your elevation increases relative to the base of the hill. The steeper the hill the more quickly your elevation changes. The slope of the hill is defined as the gradient of the hill. The steeper the hill the greater the rate of change of elevation, with respect to the horizontal component of distance traveled.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With atmospheric gradients, imagine there are two towns, each with a weather station. The distance between the two is 100 km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each weather station measures pressure &amp;amp; temperature at defined times, usually at half hourly intervals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the first town measures a pressure of 1011 hPa and temperature of 25 C @ 10 am and the second town, at 10 am, measures a pressure of 1008 hPa and a temperature of 20 C, then between the two towns there is a pressure gradient of 0.03 hPa/km [(1011-1008)/100]. Likewise there is a temperature gradient of 0.05 C/km [(25-20)/100].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, if at 11 am the weather station in the first town records a pressure of 1012.5 hPa and a temperature of 28 C, then over time, there has been a pressure gradient over the first town of 1.5 hPa/h [(1012.5-1011)/1] and a temperature gradient of 3 C/h [(28-25)/1].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So when it comes to gradients, it depends what is being measured (pressure, temperature, humidity) and what is it be measured against (distance, time, etc.), and for atmospheric quantities the distance could be lateral distance or vertical distance.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2017-09-19T09:36:15.207" LastActivityDate="2017-09-19T09:36:15.207" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12329" PostTypeId="1" AcceptedAnswerId="12330" CreationDate="2017-09-19T13:01:29.970" Score="3" ViewCount="94" Body="&lt;p&gt;I've seen many papers and sites that give the dating of Australia's Dresser Formation as 3.5 Ga (variously 3.48 or 3.49 Ga), but I can't seem to find the source of this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where does the dating come from, and what is it based on?&lt;/p&gt;&#xA;" OwnerUserId="11091" LastActivityDate="2017-12-03T00:17:28.987" Title="Source of Dresser Formation 3.5 Ga dating" Tags="|geology|dating|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12330" PostTypeId="2" ParentId="12329" CreationDate="2017-09-19T14:09:42.563" Score="3" Body="&lt;p&gt;From &lt;a href=&quot;http://dbforms.ga.gov.au/pls/www/geodx.strat_units.sch_full?wher=stratno=36957&quot; rel=&quot;nofollow noreferrer&quot;&gt;Australian Government- Geoscience AustraliaAustralian Stratigraphic Units Database&lt;/a&gt;: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://dbforms.ga.gov.au/pls/www/geodx.strat_units.sch_full?wher=stratno=14834&quot; rel=&quot;nofollow noreferrer&quot;&gt;Panorama Formation:&lt;/a&gt;  Paleoarchean min age: 3427 MA Age method: isotopic, U/Pb-Pb/Pb ion probe&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://dbforms.ga.gov.au/pls/www/geodx.strat_units.sch_full?wher=stratno=36957&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dresser Formation&lt;/a&gt;: Min Age: Ma: 3477 Age method: inferred, overlying unit&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://dbforms.ga.gov.au/pls/www/geodx.strat_units.sch_full?wher=stratno=26023&quot; rel=&quot;nofollow noreferrer&quot;&gt;McPhee Formation&lt;/a&gt;:  Min Age: 3477 Age method: isotopic, U/Pb-Pb/Pb ion probe&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-09-19T14:09:42.563" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="12331" PostTypeId="2" ParentId="12323" CreationDate="2017-09-19T17:36:03.827" Score="0" Body="&lt;p&gt;Did you check &lt;a href=&quot;https://en.wikipedia.org/wiki/Gradient&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Gradient&lt;/a&gt; ? &#xA;That's the basic definition that everybody can agree upon. &#xA;A Vector $\vec \nabla= \vec e_x \; \partial_x +\vec e_y \; \partial_y +\vec e_z \; \partial_z$ made up of three derivative components and three unit vectors $\vec e$.&lt;br&gt;&#xA;It needs to act on a scalar quantity to make sense, so only something like the mentioned Temperature gradient $\vec \nabla T$ makes sense to write down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meteorogists often speak only of one component, the horizontal one. This is not rigurously defined, as x and y are both horizontal components. But it usually means $\partial_h T$ which is the derivative of T along the direction h which is at the moment of interest, no matter what the rigid coordinate system says.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A rate of change $\frac{\partial T}{\partial x}$ is often approximated as it's discrete counterpart of finite differences $\frac{\Delta T}{\Delta x}$ (implying smooth change of T over a distance $\Delta x$).&#xA;Thus mathematically sloppy statements like 'The gradient is 2 Pa over 100 km in Northwest direction' come to life.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gradients in time are not gradients, they are rates of change. Only in General Relativity can you speak of a 4D-gradient, because time and space become the same mathematical field.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2017-09-19T17:36:03.827" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12332" PostTypeId="2" ParentId="12323" CreationDate="2017-09-19T17:45:42.027" Score="0" Body="&lt;p&gt;If there is a quantity that varies in the atmosphere, there is inherently a gradient.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since you know there is a pressure and temperature gradient, there must also be a density gradient.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is also wind speed gradients, buoyancy gradients, wind shear gradients, isentropic gradients, vorticity gradients etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;let $\chi$ be a scalar quantity with the diagnostic equation: $$\frac{\partial \chi}{\partial t}+\vec{v}\cdot \nabla \chi=F(x,y,z,t)$$, where $\vec{v}$ is the wind vector, and $F$ is the forcing term (source-sink)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore $$\nabla \frac{\partial \chi}{\partial t}=\frac{\partial \nabla\chi}{\partial t}&#xA;$$&#xA;and $$\frac{\partial \nabla\chi}{\partial t}+\nabla \vec{v}\cdot\nabla\chi+\vec{v}\cdot\nabla(\nabla\chi)=\nabla F(x,y,z,t)$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore changes in the gradient of a quantity is dependent on the changes of the advection of the quantity and the changes in the forcing of the quantity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, an advancing cold front (effectively a moving thermal gradient) can be strengthened if the cold side is cooled/warm side is warmed, or the spacing decreases.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-09-19T17:45:42.027" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12333" PostTypeId="1" AcceptedAnswerId="12389" CreationDate="2017-09-19T21:02:56.333" Score="3" ViewCount="5285" Body="&lt;p&gt;I guess the highest point of the Mount Vesuvius / Mount Somma complex is currently 1,281 metres (4,203 feet). My question is: how tall was it before it erupted in AD 79?&lt;/p&gt;&#xA;" OwnerUserId="3157" LastEditorUserId="725" LastEditDate="2017-09-20T04:17:46.367" LastActivityDate="2017-09-27T13:18:10.387" Title="how high was mount vesuvius (mount somma?) before it erupted in AD 79?" Tags="|volcanology|mountains|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12334" PostTypeId="2" ParentId="12319" CreationDate="2017-09-19T21:59:24.103" Score="1" Body="&lt;p&gt;Limited amounts of plant foods are sometimes grown indoors near sunny windows during the Antarctic summer. This doesn't violate the Antarctic treaty, because the plants do not originate in Antarctica but are grown from seeds delivered to Antarctic bases.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-09-19T21:59:24.103" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12335" PostTypeId="2" ParentId="12164" CreationDate="2017-09-20T04:30:59.430" Score="2" Body="&lt;p&gt;My house elevation is 9.1 feet above sea level, according to all &quot;expert&quot; measurements. That includes the city, county, state, Feds, and all insurers. It seems about right to me. But then again, I cannot dunk.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I live a half mile or so from the beach and bay of mustang island.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyhoo, the static water level In my hood was 2-3 feet and a little less inside my first floor. That puts it at around 10-12 feet. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's a real thing.&lt;/p&gt;&#xA;" OwnerUserId="11097" LastActivityDate="2017-09-20T04:30:59.430" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12336" PostTypeId="2" ParentId="12164" CreationDate="2017-09-20T14:31:05.903" Score="3" Body="&lt;p&gt;For a general view of the surge in the region, the maps in &lt;a href=&quot;https://www.u-surge.net/hurricane-harvey.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;u-surge&lt;/a&gt; give a pretty good idea of numbers and more affected regions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://stn.wim.usgs.gov/fev/#HarveyAug2017&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS&lt;/a&gt; provides a comprehensive view of High Water Marks (&lt;a href=&quot;https://en.wikipedia.org/wiki/High_water_mark&quot; rel=&quot;nofollow noreferrer&quot;&gt;HWM&lt;/a&gt;) in the entire region. If you are looking for observations, then the HWM database gives you the best spatial coverage. While HWM do not provide surge information per se as it includes multiple processes (like ocean &lt;a href=&quot;https://en.wikipedia.org/wiki/Storm_surge&quot; rel=&quot;nofollow noreferrer&quot;&gt;surge&lt;/a&gt; from the storm, waves and wave run-up, and flooding from rivers and precipitation), it gives an idea of the extreme values of water level in many locations. It also shows the large spatial variability of the effects of the storm. There are also tide gauge and rapid response stations in the area as part of the USGS database that provides more information of the temporal evolution of water levels. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Part of the problem is that storm surge is only the result of two processes: 1) wind piling water against the coast and 2) low atmospheric pressure that causes ocean level to go up. Additionally, you have many other processes affecting water levels during a storm or hurricane. The tides are still there as always and that adds complications because if the storm surge peak occurs during high tide, then the impacts are much worse. Tides in the Gulf of Mexico are not that high, but they can be a much larger factors in some other areas. The combination of storm surge and astronomical tides is often label &quot;storm tide&quot;, which is a very poor name choice and leads to much confusion, as clearly the storm does not cause a tide. Another impact is that associated with the high winds, you have large &lt;a href=&quot;https://en.wikipedia.org/wiki/Wave_height&quot; rel=&quot;nofollow noreferrer&quot;&gt;wave heights&lt;/a&gt;. As these high waves approach the coast, they cause higher water levels as a result of &lt;a href=&quot;http://homepages.cae.wisc.edu/~chinwu/GLE401/web/Mike/Wave%20runup.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;wave run-up&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Wave_setup&quot; rel=&quot;nofollow noreferrer&quot;&gt;wave setup&lt;/a&gt;. The magnitude of these wave effects can be pretty large in some locations especially in ocean-facing locations. The last main impact on water level is precipitation and the resulting increase river discharge. Clearly, Harvey had a catastrophic &lt;a href=&quot;https://earthscience.stackexchange.com/questions/12159/how-can-a-storm-drop-40-inches-1-metre-of-rain&quot;&gt;amount of precipitation&lt;/a&gt; and its impacts were much larger than the purely oceanic-driven storm surge in this storm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many agencies are working on developing a measure of water level that includes all these processes. For instance a good example is the USGS effort to develop &lt;a href=&quot;https://coastal.er.usgs.gov/hurricanes/research/operational-models.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Total Water Level&lt;/a&gt; measurements and &lt;a href=&quot;https://coastal.er.usgs.gov/hurricanes/research/twlviewer/&quot; rel=&quot;nofollow noreferrer&quot;&gt;forecast&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2017-09-20T14:31:05.903" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12337" PostTypeId="2" ParentId="6" CreationDate="2017-09-20T14:58:39.843" Score="-2" Body="&lt;p&gt;Upper atmospheric pressure is lower than surface pressure which entails higher elevation clouds will indeed move faster than lower elevation clouds which will move at slower speeds.&lt;/p&gt;&#xA;" OwnerUserId="11101" LastActivityDate="2017-09-20T14:58:39.843" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12339" PostTypeId="1" CreationDate="2017-09-21T03:04:46.400" Score="4" ViewCount="71" Body="&lt;p&gt;Is there what could be called a &quot;global disaster index&quot;, i.e., a measure of the number, weighted by their intensities, of all the world's natural disasters at given moments in time throughout history?&lt;/p&gt;&#xA;" OwnerUserId="11105" LastEditorUserId="11105" LastEditDate="2017-09-21T03:11:47.967" LastActivityDate="2017-09-21T03:11:47.967" Title="Is there a sort of &quot;global natural disaster&quot; index?" Tags="|measurements|natural-disasters|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="12344" PostTypeId="1" AcceptedAnswerId="12345" CreationDate="2017-09-21T13:55:54.417" Score="4" ViewCount="819" Body="&lt;p&gt;In most of the earthquake footages filmed outside during the earthquake that hit Mexico City on September 9, 2017 there was a distinctive streak of hum in rapid succession that could be heard in the background. It sounded like someone is constantly hitting the tuning forks onto a light tower like 2 times per second.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can find &lt;a href=&quot;https://www.youtube.com/results?search_query=mexico%20city%20earthquake%20footage&quot; rel=&quot;nofollow noreferrer&quot;&gt;numerous footages on youtube&lt;/a&gt;, but I picked one and fetched the audio portion covering the hums, you can listen to the audio &lt;a href=&quot;https://soundcloud.com/fahadash-1/sound-of-earthquake-in-mexico-9192017&quot; rel=&quot;nofollow noreferrer&quot;&gt;at this link here&lt;/a&gt; (sorry I did not know how to upload an audio to SE).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is the waveform of the sound&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/g1zK8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/g1zK8.png&quot; alt=&quot;Mexico City Earthquake Waveform&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is that sound? What is causing this sound? If this was buildings or surrounding objects, why is there a pattern? Why is this sound heard in every footage no matter where they are filmed as long as they were filmed outside.&lt;/p&gt;&#xA;" OwnerUserId="1009" LastActivityDate="2017-09-21T14:26:30.690" Title="What is that spooky humming sound heard in earthquake footages?" Tags="|earthquakes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12345" PostTypeId="2" ParentId="12344" CreationDate="2017-09-21T14:26:30.690" Score="8" Body="&lt;p&gt;Wailing sirens. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Examples &lt;a href=&quot;https://youtu.be/Z_bueA1XQqg?t=2m33s&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;https://youtu.be/yAun0cs_cGc?t=28s&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt; where you see people come running out, i.e. exactly when you'd expect sirens, or &lt;a href=&quot;https://www.youtube.com/watch?v=86QMhxHd404&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;, or &lt;a href=&quot;https://www.youtube.com/watch?v=4RxFFX_f1II&quot; rel=&quot;noreferrer&quot;&gt;4&lt;/a&gt; and &lt;a href=&quot;https://www.youtube.com/watch?v=QGanqZJ-Pz8&quot; rel=&quot;noreferrer&quot;&gt;5&lt;/a&gt; where they are explicitly mentioned.&lt;/p&gt;&#xA;" OwnerUserId="595" LastActivityDate="2017-09-21T14:26:30.690" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12346" PostTypeId="1" CreationDate="2017-09-21T16:43:34.883" Score="2" ViewCount="88" Body="&lt;p&gt;I found this rock near my home in the high desert of south central Utah (near Capitol Reef National Park). The sides are symmetrical and smooth -- shaped somewhat like a canoe. It is 6 1/2&quot; long; 1 1/2&quot; at widest point. The top is sheared off and sparkles in the light. It is embedded with flakes of a shiny, black glasslike material, possibly obsidian. The Fremont culture occupied the area and left an abundance of tools, points, and chip rock, many of which were sourced from elsewhere; most likely the result of trading. A neighbor and I came up with an uninformed theory. Would appreciate any informed observations.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/nMjTA.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nMjTA.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11110" LastActivityDate="2017-09-26T17:09:18.170" Title="What is this canoe-shaped rock with obsidian? flakes?" Tags="|geology|" AnswerCount="1" CommentCount="3" ClosedDate="2019-08-29T19:43:19.053" ContentLicense="CC BY-SA 3.0" />
  <row Id="12347" PostTypeId="1" AcceptedAnswerId="12383" CreationDate="2017-09-21T21:26:49.213" Score="6" ViewCount="94" Body="&lt;p&gt;I have been watching The Weather Channel for a month straight following the hurricanes. One of the meteorologists warned people not to drive into floodwaters, saying that water moving at about 6 miles per hour has the same amount of power as an EF5 tornado.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How did they figure that out?&lt;/p&gt;&#xA;" OwnerUserId="11114" LastEditorUserId="6298" LastEditDate="2017-09-28T03:31:15.353" LastActivityDate="2017-09-28T03:31:15.353" Title="How does the energy of tornadic winds compare to floodwaters?" Tags="|meteorology|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12348" PostTypeId="1" CreationDate="2017-09-22T01:57:11.583" Score="3" ViewCount="715" Body="&lt;p&gt;In the introduction of &quot;&lt;a href=&quot;http://shoni2.princeton.edu/ftp/lyo/journals/Cai-etal-RossbyRadiusSCS-JMS2008.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geographical and monthly variability of the first baroclinic Rossby radius of deformation in the South China Sea&lt;/a&gt;&quot;, the authors states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In both theoretical and observational studies of large and meso-scale oceanic processes, the first baroclinic Rossby radius of deformation (R1) is an important quantity in determining horizontal scales which characterize eddy sizes, trapping scales for coastal jets and equatorial flows.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I am familiar with the fact that R1 can determine eddy sizes (e.g., &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2227/how-is-the-rossby-radius-used-to-determine-that-synoptic-weather-systems-are-100&quot;&gt;this answer&lt;/a&gt;), but I am having an hard time to find references about trapping scales for coastal jets and equatorial flows.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can someone, please, give me some explanations and/or references?&lt;/p&gt;&#xA;" OwnerUserId="6001" LastActivityDate="2019-04-20T03:22:03.390" Title="Rossby radius as horizontal scale" Tags="|geophysics|oceanography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12349" PostTypeId="2" ParentId="12261" CreationDate="2017-09-22T11:53:41.763" Score="2" Body="&lt;p&gt;While Knobscratcher's answer is technically correct that there may be some correlation between the Moon, Earthquakes and Ocean currents and Weather that lead to Hurricanes, that correlation is not confirmed, it's only been determined to be possible and to make a direct correlation is pretty thin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What's more, a Solar Eclipse is not only fairly common but it's not a peak tidal tugging event.  There's no reason for a solar eclipse to be any different than any other period in the Moon's orbit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Certainly throughout history it was quite common to believe that eclipses or comets could forecast destructive events.   This belief, for obvious reasons, waned when better understanding of the orbits of the Earth and Moon explained why eclipses happened and made them predictable but it's natural, if somewhat unscientific, to try to make a correlation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's about 70 per century and if we include partial and annular, over 200 per century.    See:  &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_solar_eclipses_in_the_20th_century&quot; rel=&quot;nofollow noreferrer&quot;&gt;20th Century&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_solar_eclipses_in_the_21st_century&quot; rel=&quot;nofollow noreferrer&quot;&gt;21st Century&lt;/a&gt;.    Eclipses are common enough that natural disasters following eclipses shouldn't surprise anyone.   It's statistically curious that an Eclipse, 3 major hurricanes (4 if you count Max that hit Mexico, but I don't think that was major), and two major Earthquakes all hit North America over a few weeks.   That's curious, but there's basically zero good science that ties all those events together in an armegedonish kind of way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hurricanes are often be very seasonal, where optimal conditions can lead to greater hurricane formation.    Hurricane formation is complicated, and I'm not an expert, but &lt;a href=&quot;http://news.nationalgeographic.com/2017/09/hurricane-irma-harvey-season-climate-change-weather/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; touches on some of the basics - scroll down to &quot;Why is this season so active&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Factors like a strong west African monsoon and consistent wind speeds surface to 10 miles up and warm oceans (that much is partially due to climate change), and a neutral El Nino.   These are factors that can make a hurricane season more or less active and a strong hurricane season was predicted months ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earthquakes operate differently, usually building up gradually for years - and like a very slow game of Jenga, when the pressure surpasses the resistance holding the ground in place, you get rapid movement.   It may be theorized that hurricanes and weather may occasionally trigger Earthquakes, but the potential for an Earthquake still needs to be there in the first place and to say the &quot;wind and rain did it&quot; is still pretty tenuous.  The two Mexico quakes happened along the Ring of Fire where Earthquakes are fairly common and one following another a few weeks later is also not uncommon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To say there's no relation is perhaps not the scientific thing to say, but it's very likely that there's almost no relation between the active hurricane season which was anticipated before it happened, due to the right combination of ocean and weather pasterns, and two Earthquakes in an Earthquake prone region, where Earthquakes are expected to happen every several years to couple of decades.   And these two events are over 1,000 miles away from each other.  (unless you count Hurricane Max which was closer to the Earthquakes but just a category one). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Coincidence is the most logical answer and tying the eclipse to these events as well, any correlation there is to thin to contemplate.    &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2017-09-22T11:53:41.763" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12351" PostTypeId="2" ParentId="12348" CreationDate="2017-09-22T15:38:07.387" Score="5" Body="&lt;p&gt;The Rossby radius of deformation tells you the distance when the Coriolis effect becomes just as important as the buoyancy or gravity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let the Rossby radius of deformation be denoted as $L_R$. According to Holton's Fifth Edition of &quot;An introduction to Dynamic Meteorology,&quot;  $$L_R=\frac{NH}{f_0}$$ where $N$ is the Brunt-Vaisala frequency, $H$ is the scale height, and $f_0$ is the Coriolis parameter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For phenomena with length scale $L$, buoyancy can be neglected if $L&amp;lt;&amp;lt;L_R$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In statically stable equatorial flows, $$\lim_{f_0\to 0} L_R=\infty$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In certain coastal flows, $L \approx L_R$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the author is saying that in equatorial flows, buoyancy can't be neglected, since the Rossby radius &quot;blows up&quot; and for coastal flows $L\approx L_R$&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-09-22T15:38:07.387" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12352" PostTypeId="1" CreationDate="2017-09-22T16:55:30.017" Score="3" ViewCount="31" Body="&lt;p&gt;I have 250 or so soil sensors that I need to QC. They monitor various parameters such as soil temp, soil water content, soil co2, and soil heat flux. It isn't unusual for a sensor to behave poorly due to elk chewing up wires a little bit, electrical noise, and what not.&lt;/p&gt;&#xA;&lt;p&gt;I already use some basic scripts to filter out based on moving averages, standard deviation, and physical constraints. Sometimes there are sensors that still have bad data, such as this soil water. It looks like there is still a viable signal in that noise that is traced out by a bunch of local minima, and I've confirmed this pattern with nearby sensors.&lt;/p&gt;&#xA;&lt;p&gt;I've played around with some finite-impulse response filters in MATLAB to try to remove the noise, but I don't really know how to design one of these at all.&lt;/p&gt;&#xA;&lt;p&gt;Any suggestions, resources, or other filters that could help with QCing this?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/u88SS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/u88SS.png&quot; alt=&quot;Soil water content at 5 cm&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11122" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-09-22T16:55:30.017" Title="Designing FIR or other filters for soil water content" Tags="|hydrology|soil|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12353" PostTypeId="1" AcceptedAnswerId="16761" CreationDate="2017-09-22T17:35:34.777" Score="6" ViewCount="1463" Body="&lt;p&gt;The Navier-Stokes equations are a set of nonlinear differential equations that diagnose wind speed and direction. They are (approximately) expressed as $$\frac{d\vec{u}}{dt}=-\frac{1}{\rho}\nabla P+f\hat{k}\times\vec{u}-g\hat{k}+\nu \nabla^2\vec{u}$$Where $\frac{d}{dt}=\frac{\partial}{\partial t}+u\frac{\partial}{\partial x}+v\frac{\partial}{\partial y}+w\frac{\partial}{\partial z}$, $f$ is the coriolis parameter, $\rho$ is density, $P$ is pressure, $g$ is gravity, $\nu$ is the kinematic viscosity, and $\vec{u}$ is the wind vector.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In synoptic meteorology, it is taught that in jet streaks, the curvature of the jet streak influences the acceleration by the centrifugal force. However, in the equation above, I see no centrifugal component.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is curvature-based centrifugal motion simply missing, or is it hidden? If it is missing, how would it be expressed (in Cartesian coordinates)? If it is hidden, in which term is it hiding? Could we decompose it into centrifugal and non-centrifugal acceleration? A derivation of cyclostrophic would be sufficient, since it will explicitly say from what part of the equation is curvature.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorDisplayName="user12525" LastEditDate="2019-04-17T12:15:05.003" LastActivityDate="2019-04-28T08:57:33.020" Title="Centrifugal Force in the Navier Stokes Equations" Tags="|meteorology|atmosphere|jet-stream|" AnswerCount="2" CommentCount="15" ContentLicense="CC BY-SA 3.0" />
  <row Id="12354" PostTypeId="1" CreationDate="2017-09-22T18:12:53.153" Score="2" ViewCount="50" Body="&lt;p&gt;How much different in temperature and pressure can a microclimate be than the surrounding region?  In other words, if you had a dry region but then a valley within a ring of mountains that isolated the local environment could the valley have distinctly different humidity, temperature and pressure and how far much different could it get?  &lt;/p&gt;&#xA;" OwnerUserId="11120" LastActivityDate="2017-09-23T20:25:40.127" Title="How different can microclimates be than their surrounding areas?" Tags="|meteorology|atmosphere|climate|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12357" PostTypeId="1" CreationDate="2017-09-22T23:58:29.057" Score="2" ViewCount="1156" Body="&lt;p&gt;For instance, coastal areas are often foggy in the morning. Then the sun “burns it off”. Where does the moisture go? I’m curious of the star’s (i.e. Sun) influence on evaporation effects. &lt;/p&gt;&#xA;" OwnerDisplayName="iMerchant" LastEditorUserId="725" LastEditDate="2017-09-23T05:36:52.133" LastActivityDate="2022-02-14T16:59:23.993" Title="Where does water vapor go/what does the sun do?" Tags="|atmosphere|evaporation|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12358" PostTypeId="2" ParentId="12357" CreationDate="2017-09-23T04:59:01.597" Score="7" Body="&lt;p&gt;Simplistically, fog consists of water droplets.  The sun provides energy, which heats the droplets and evaporates them, and also raises the air temperature.  The water is still there, it's just in the form of (transparent) water vapor, rather than light-scattering droplets.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS: Maybe a similar example would help make things clear.  Say you've just washed some clothes, and hang them on the line, and some time later they're dry.  There was water in the clothes when you hung them out, it didn't drip off the bottom, so where did the water go?  Into the air, as vapor, no?  Same with fog, when the sun raises the temperature a bit.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastEditorUserId="1401" LastEditDate="2017-09-24T04:53:13.177" LastActivityDate="2017-09-24T04:53:13.177" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12359" PostTypeId="2" ParentId="12357" CreationDate="2017-09-23T09:04:56.833" Score="4" Body="&lt;p&gt;The occurrence and disappearance of fog is due to the &lt;a href=&quot;http://www.weatherquestions.com/What_is_dewpoint_temperature.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;dew point&lt;/a&gt;, which is:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;the temperature at which the air can no longer &amp;quot;hold&amp;quot; all of the water vapor which is mixed with it, and some of the water vapor must condense into liquid water. The dew point is always lower than (or equal to) the air temperature.&lt;/p&gt;&#xA;&lt;p&gt;If the air temperature cools to the dew point, or if the dew point&#xA;rises to equal the air temperature, then dew, fog or clouds begin to&#xA;form.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Some people talk of the sun burning off the fog. All that happens is the sun warms the air to temperature greater than the dew point and the small droplets of water that condensed out of the atmosphere to produce the fog re-vaporize and can no longer be seen.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-09-23T09:04:56.833" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12361" PostTypeId="2" ParentId="12354" CreationDate="2017-09-23T13:23:49.430" Score="2" Body="&lt;p&gt;Elevation is often responsible for the biggest differences; you can have snow and glaciers on the top of mountains in warm climates. South America can show you how extreme the differences in precipitation can be: rain forest on one side of the Andes Mountains, world's driest (non-polar) desert on the other. So really it depends on how high and complete your mountain ring is.&#xA;&lt;a href=&quot;https://books.google.com/books?id=LHUZDAAAQBAJ&amp;amp;pg=PA144&amp;amp;lpg=PA144&amp;amp;dq=plateau%20microclimate&amp;amp;source=bl&amp;amp;ots=QmEXUdFTNK&amp;amp;sig=0YDHV2d4TTJDJe4IzWRj8aDMHXU&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwipgoufs7vWAhVEbSYKHcFWA-MQ6AEIVzAN#v=onepage&amp;amp;q=plateau%20microclimate&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; is a decent book on the subject. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="6298" LastEditDate="2017-09-23T20:25:40.127" LastActivityDate="2017-09-23T20:25:40.127" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12368" PostTypeId="1" CreationDate="2017-09-25T10:24:26.420" Score="2" ViewCount="51" Body="&lt;p&gt;Mapping the bottom of the ocean is called seafloor mapping.  I was wondering what mapping underground is called, such as when locating caves and caverns.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have seen it in movies, and I'm interested to know what is it called so that I can start searching for more info about it.&lt;/p&gt;&#xA;" OwnerUserId="11148" LastEditorUserId="6298" LastEditDate="2017-09-26T02:54:25.537" LastActivityDate="2017-09-26T02:54:25.537" Title="How to map (survey) the structure of crust" Tags="|mapping|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12369" PostTypeId="2" ParentId="12368" CreationDate="2017-09-25T10:37:03.737" Score="3" Body="&lt;p&gt;What you have probably seen in the movies, as used by the oil and gas industry is &lt;a href=&quot;https://en.wikipedia.org/wiki/Reflection_seismology&quot; rel=&quot;nofollow noreferrer&quot;&gt;reflection seismology&lt;/a&gt;. This is where you shoot off a sound source (explosives, airguns, etc) and track the reflections of the sound waves from the various rock layers below the surface.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At a smaller scale, there is &lt;a href=&quot;https://en.wikipedia.org/wiki/Ground-penetrating_radar&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ground Penetrating Radar&lt;/a&gt;, good for a few 10s of meters at best, which is higher resolution and good for detecting voids.&lt;/p&gt;&#xA;" OwnerUserId="8217" LastActivityDate="2017-09-25T10:37:03.737" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12370" PostTypeId="2" ParentId="12368" CreationDate="2017-09-25T12:40:01.880" Score="3" Body="&lt;p&gt;As Andrew Jon Dodds states in his answer, underground voids can be located using reflection seismology. The results of such surveys will given an indication the size and extend of underground voids. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once a void has been located a more accurate layout of the underground void can be obtained by conducting a &lt;a href=&quot;https://en.wikipedia.org/wiki/Cave_survey&quot; rel=&quot;nofollow noreferrer&quot;&gt;cave survey&lt;/a&gt;. This requires people to enter caves/voids &lt;a href=&quot;http://cavingintro.net/surveymap.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;with measuring equipment and to draw a diagram of the cave&lt;/a&gt;, similar to how former maritime navigators charted coast lines. &lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-09-25T12:40:01.880" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12371" PostTypeId="1" CreationDate="2017-09-26T02:03:28.080" Score="1" ViewCount="358" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/gZ5qK.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We found this rock at a mineral and jewelry store. The gal wrote down what it was and we cannot find what we think she wrote on the internet anywhere. She wrote Mcstrodlite.&lt;img src=&quot;https://i.stack.imgur.com/NjNxp.jpg&quot; alt=&quot;![enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="11149" LastEditorUserId="595" LastEditDate="2019-11-08T11:30:27.057" LastActivityDate="2019-11-08T11:30:27.057" Title="Is this a fossil we found in a store?" Tags="|geology|fossils|" AnswerCount="2" CommentCount="0" ClosedDate="2019-07-19T10:46:17.207" ContentLicense="CC BY-SA 4.0" />
  <row Id="12372" PostTypeId="1" CreationDate="2017-09-26T04:47:00.120" Score="3" ViewCount="819" Body="&lt;p&gt;A lot of times, ancient artifacts or even whole ancient civilizations are found buried very deep into the ground surface of the earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Entire civilizations that had high buildings have been found many meters below the earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does that mean the earth's sea-level was much lower than it is now? If this is true, then are we experiencing a lower level of gravity?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can just sedimentation of sand, bury big building to such depths?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If lack of habitation by humans eventually results in burying of things, then what about the places like Chernobyl, which has not been inhabited for a long time?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not a physics grad or anything, just a curious guy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any help is much appreciated.&lt;/p&gt;&#xA;" OwnerUserId="11151" LastActivityDate="2017-10-02T15:13:53.773" Title="Was the Earth's sea-level significantly lower in ancient times?" Tags="|earth-history|sea-level|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12373" PostTypeId="2" ParentId="7363" CreationDate="2017-09-26T09:53:25.517" Score="4" Body="&lt;p&gt;It is far too complex a process to estimate surface irradiances utilising satellite data. No software takes just satellite images as input and gives out irradiances. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am pasting link to an article that describes algorithm to convert geostationary satellite measurements to surface reaching solar irradiance. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://dx.doi.org/10.1029/2007JD009308&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gadhavi et al., 2008; doi: 10.1029/2007JD009308&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To summarise following are most important aspects in estimating surface radiation budget. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Calibration constants to convert photon counts measured by satellite sensor to radiance&lt;/li&gt;&#xA;&lt;li&gt;Parameterisation scheme to convert narrow band satellite radiances to broadband radiances. &lt;/li&gt;&#xA;&lt;li&gt;surface optical characteristics as function of wavelength, sun elevation and season&lt;/li&gt;&#xA;&lt;li&gt;Geophysical parameters like cloud amount, aerosol amount, ozone, etc. (Essentially these are the real satellite input in whole process). &lt;/li&gt;&#xA;&lt;li&gt;Radiative transfer model to estimate irradiances using inputs received from satellite and other sources.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;There are few web-site where one can directly get final output of irradiance values. See following link. &#xA;&lt;a href=&quot;https://data.noaa.gov/dataset/surface-radiation-budget-surfrad-network-1-hour-observations&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://data.noaa.gov/dataset/surface-radiation-budget-surfrad-network-1-hour-observations&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="10780" LastEditorUserId="10780" LastEditDate="2017-12-15T08:45:23.067" LastActivityDate="2017-12-15T08:45:23.067" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12374" PostTypeId="1" AcceptedAnswerId="12385" CreationDate="2017-09-26T10:21:06.277" Score="2" ViewCount="62" Body="&lt;p&gt;Spring/September temperature records on Australia's East coast are set to tumble in the coming days, due to a heatwave, as described &lt;a href=&quot;http://mobile.abc.net.au/news/2017-09-21/bom-forecasts-sydney-heatwave-with-36c-expected-on-saturday/8965442?pfmredir=sm&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the hot air is being pulled from the interior of the continent to the coast. That makes sense. But some of the towns in the interior of the country are setting temperature records as well. So what is the explanation for why the air in the interior is the hottest on record? What is the ultimate cause of the hot air?&lt;/p&gt;&#xA;" OwnerUserId="7027" LastEditorUserId="6298" LastEditDate="2017-09-26T17:22:46.570" LastActivityDate="2017-09-26T23:29:02.093" Title="Where is the hot air for Australia's record spring heatwave coming from?" Tags="|temperature|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12375" PostTypeId="1" CreationDate="2017-09-26T13:33:07.277" Score="4" ViewCount="69" Body="&lt;p&gt;since there are topological isolation as well as prominence as measures to describe how &quot;dominant&quot; a summit is in comparison to the ones surrounding it, I was thinking about a similar measure to describe the dominance of a city in terms of population.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This would be a nice asset for an automatic map labeling system which labels cities on a map, omitting suburbs of a bigger city right next to them and featuring smaller towns which are the biggest cities in a certain radius, though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can think of it as a function which takes the population of a city and the distance to the next more populous city and generates some kind of &quot;dominance score&quot;. The higher it is, the more likely it is to be featured on a map.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So are there already any algorithms covering this? Or maybe just &quot;best practices&quot; I can use?&lt;/p&gt;&#xA;" OwnerUserId="11153" LastActivityDate="2017-11-25T18:54:57.383" Title="Is there a measure for the &quot;dominance&quot; of a city's population?" Tags="|geography|mapping|geospatial|gis|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12377" PostTypeId="1" AcceptedAnswerId="12378" CreationDate="2017-09-26T13:59:11.673" Score="13" ViewCount="16791" Body="&lt;p&gt;There are a few impressive photographs of giant sinkholes that appeared in cities, such as this one:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QGRkK.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QGRkK.jpg&quot; alt=&quot;Guatemalan sinkhole&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, followup information (e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/2010_Guatemala_City_sinkhole#Filling_in_the_sinkhole&quot; rel=&quot;noreferrer&quot;&gt;Guatemalan sinkhole&lt;/a&gt;) or photographs on how these kind of sinkholes are filled up is hard to find. What approaches may be taken to &quot;repair&quot; or filling up these?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If dumping more earth or materials into them is ineffective due to underground-water, how can they be covered up properly without causing another collapse?&lt;/p&gt;&#xA;" OwnerUserId="11154" LastActivityDate="2017-10-04T19:56:03.353" Title="How are giant sinkholes filled up?" Tags="|rocks|geomorphology|underground-water|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12378" PostTypeId="2" ParentId="12377" CreationDate="2017-09-26T15:03:57.060" Score="14" Body="&lt;p&gt;&lt;a href=&quot;https://www.wired.com/2016/11/fukuoka-japan-sinkhole/&quot; rel=&quot;nofollow noreferrer&quot;&gt;How Japan Filled That Ginormous Sinkhole In Just One Week&lt;/a&gt;:&lt;br /&gt;&#xA;The Fukuoka sinkhole measuring 8,700 square feet (808 square meter), 65 foot (20 m) deep: &lt;em&gt;they poured a mixture of soil, water, and cement into the hole—they use more than 7,100 cubic meters of the stuff in all&lt;/em&gt;. &lt;a href=&quot;https://www.youtube.com/watch?v=sKtUtesU_KY&quot; rel=&quot;nofollow noreferrer&quot;&gt;YouTube timelapse&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.slate.com/articles/news_and_politics/explainer/2010/06/how_to_fix_a_giant_sinkhole.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;How To Fix a Giant Sinkhole&lt;/a&gt; about the two in Guatemala:&lt;br /&gt; The first from 2007 one they filled with a soil cement made from cement, limestone, and water known locally as lodocreto (&quot;mudcrete&quot;).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It's not clear whether cement is the best option, however. A 6,500-cubic-foot wad of concrete may serve to concentrate water runoff in other areas, leading to more sinkholes. Many engineers prefer the graded-filter technique, in which the hole is filled with a layer of boulders, then a layer of smaller rocks, and, finally, a layer of gravel. This fills the hole, more or less, while permitting water to drain through the area.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Whether this was actually done with the 2010 one I could not find (yet). Even the &lt;a href=&quot;https://en.wikipedia.org/wiki/2010_Guatemala_City_sinkhole#Filling_in_the_sinkhole&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia entry on the 2010 sinkhole&lt;/a&gt; (which you are also refering to) says &lt;em&gt;This section needs to be updated&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems to be closed now, look at &lt;a href=&quot;https://youtu.be/hvam_sEuaSU?t=1m41s&quot; rel=&quot;nofollow noreferrer&quot;&gt;this video fragment&lt;/a&gt; compared with the &lt;a href=&quot;http://enriquemontalar.com/glosarios-y-sinkholes-en-guatemala/&quot; rel=&quot;nofollow noreferrer&quot;&gt;bottom picture here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that 7000-8000 m&lt;sup&gt;3&lt;/sup&gt; sounds like a lot, but that is only 400-500 truck loads.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;BTW (I know, that is not answering the question, but it was too nice to not add):&lt;br /&gt;Instead of filling them up you can also &lt;a href=&quot;http://www.amusingplanet.com/2017/10/a-garden-in-sinkhole.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;make a garden in them&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0J3cH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0J3cH.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;sup&gt;Photo credit: &lt;a href=&quot;https://www.flickr.com/photos/knitspirit/6962178785/&quot; rel=&quot;nofollow noreferrer&quot;&gt;KnitSpirit/Flickr&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="595" LastEditorUserId="595" LastEditDate="2017-10-04T19:56:03.353" LastActivityDate="2017-10-04T19:56:03.353" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12379" PostTypeId="2" ParentId="12375" CreationDate="2017-09-26T17:00:00.977" Score="1" Body="&lt;p&gt;Exciting question... it's something I've wondered as well, both for interest purposes and for utility in programs like you mention (I posed a fairly related question in the cartography SE site proposal).  I've searched a long time but could not find any term/calculation for this... perhaps I too just did not know the correct term to use?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a result, for a very basic calculation, I created an Excel spreadsheet and worked with US locations to formulate a simplistic prominence... calculating just the distance each city is from the nearest larger city.  The outcome was this &lt;a href=&quot;https://www.sporcle.com/games/JeopardyTempest/this_land_is_my_land&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sporcle quiz&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My results are likely not of great use for within a mapping program, as it takes no account of the degree of relative population size... but certainly would be interested in knowing more about that as well, as I've looked for a way to better prioritize the cities shown in a weather mapping solution I use.  Not sure you'd be able to use contouring methods given the discretized nature of population.  Instead I'd imagine perhaps iterating until you find the radius from the city border centroid where the surrounding population matches the population of the city.   That sound like a more complex GIS problem, one I've considered asking before but haven't even been sure how to narrow down into a basic enough question for SE!  Still, if there's no luck here of existing formulas, and you work out what way you want to calculate such a prominence (and can then boil it down to a basic question) &lt;a href=&quot;https://gis.stackexchange.com/&quot;&gt;GIS StackExchange&lt;/a&gt; may be the place to try.  Hopefully you'll give us the link to any questions you propose there so users here can follow any resolution!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the basic prominence I calculated is somehow useful, I could dig up the full spreadsheet.  I believe I also might have found a potential global dataset as well, but never followed it up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I cannot exaggerate how exciting it is to see someone else thinking about this topic, and hope your question brings some further better answers from those in the know!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-09-26T17:09:29.797" LastActivityDate="2017-09-26T17:09:29.797" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12380" PostTypeId="2" ParentId="12371" CreationDate="2017-09-26T17:02:28.553" Score="0" Body="&lt;p&gt;Looks similar to stromatolite.&lt;/p&gt;&#xA;" OwnerUserId="11156" LastActivityDate="2017-09-26T17:02:28.553" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12381" PostTypeId="2" ParentId="12346" CreationDate="2017-09-26T17:09:18.170" Score="4" Body="&lt;p&gt;Black elongated crystals are mostly hornblendes. The rock itself is (probably) horblende andersite or hornblende dacite. Both are intermediate volcanic rocks.&lt;/p&gt;&#xA;" OwnerUserId="11156" LastActivityDate="2017-09-26T17:09:18.170" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12382" PostTypeId="1" CreationDate="2017-09-26T17:47:26.347" Score="4" ViewCount="359" Body="&lt;p&gt;I recently learned about slab rollback, specifically of the Juan de Fuca plate subducting underneath the North American plate. From what I understand, the subducting plate over time begins descending at a steeper rate, &quot;pulling&quot; the trench and the above converging plate back (towards the direction of the subducting plate). What makes the subducting plate begin to sink at a steeper incline? My guess is an increase in the density of the plate allows it to descend steeper, but I don't know of any evidence to prove that.&lt;/p&gt;&#xA;" OwnerUserId="7307" LastActivityDate="2017-09-26T17:47:26.347" Title="For slab rollback, what allows the subducting plate to begin descending at a steeper incline?" Tags="|geology|plate-tectonics|tectonics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12383" PostTypeId="2" ParentId="12347" CreationDate="2017-09-26T18:21:30.947" Score="7" Body="&lt;ul&gt;&#xA;&lt;li&gt;The force exerted by a moving fluid (gas or liquid) per unit area is&#xA;proportional to its density $D$ and to the square of its velocity $V^2$.&lt;/li&gt;&#xA;&lt;li&gt;The power delivered by a moving fluid (gas or liquid) per unit area&#xA;is proportional to its density $D$ and to the cube of its velocity $V^3$.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Water is about $800$ times as dense as air.&lt;br&gt;&#xA;So water moving at $(\frac{1}{800})^{1/2}$ or about $\frac{1}{28}$ as fast as air exerts the same force per unit area,&lt;br&gt;&#xA;and water moving at $(\frac{1}{800})^{1/3}$ or about $\frac{1}{9}$ as fast as air delivers the same power per unit area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or in other words air must move $800^{1/2}$ or about $28$ times as fast as water to exert the same force per unit area, and $800^{1/3}$ or about $9$ times as fast to deliver the same power per unit area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus water moving at $6$ mph exerts the same force per unit area as air moving at about $170$ mph (a $170$ mph wind), and delivers the same power per unit area as air moving at about $55$ mph (a $55$ mph wind).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;So it is not the power of 6 mph water that equals that of an EF4 (not EF5) tornado, but the force.&lt;br&gt;&#xA;$6$ mph water has the same power as a 55 mph whole gale.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="8382" LastEditorUserId="8382" LastEditDate="2017-09-27T18:41:44.260" LastActivityDate="2017-09-27T18:41:44.260" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12384" PostTypeId="2" ParentId="12347" CreationDate="2017-09-26T23:03:19.417" Score="2" Body="&lt;p&gt;In addition to the answer posted by Jack, there is also buoyancy that must be accounted for.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By shear force, six inches of water will sweep you off your feet. Effectively what could happen is the same as taking a dive into a shallow water slide- possible head injury and the possibility of drowning, alongside being swept away. &lt;a href=&quot;https://www.fema.gov/media-library-data/20130726-1621-20490-2826/floodsfactsheet_finalrev2_5_07.txt&quot; rel=&quot;nofollow noreferrer&quot;&gt;Those same six inches may flood your car&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.fema.gov/media-library-data/20130726-1621-20490-2826/floodsfactsheet_finalrev2_5_07.txt&quot; rel=&quot;nofollow noreferrer&quot;&gt;One foot of water, even stagnant water, will float your car&lt;/a&gt;. If the water is rapidly moving, I'd hypothesize it may even roll your car, maybe even carry it off.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An EF2 tornado has wind speeds of 111-135 mph and can lift cars off the ground, but might not be thrown. An EF3 tornado, with wind speeds between 136-165 mph, will throw cars.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Very few people are foolish enough to drive into tornadoes (the tornado interceptors are an exception- they have proper equipment). The same can't be said about floodwaters. I've seen people drive through unsafe waters during a rain storm and have their cars stall in the middle of the road.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2017-09-26T23:44:11.157" LastActivityDate="2017-09-26T23:44:11.157" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12385" PostTypeId="2" ParentId="12374" CreationDate="2017-09-26T23:29:02.093" Score="1" Body="&lt;p&gt;There are 2 causes of record high daytime temperatures: insolation and subsidence. As air is forced to subside, heat of compression adds to insolation. This happens at the poleward margins of the tropical Hadley cells, at or near the latitude where the deserts of Australia are located. Cloud cover (or dustiness in deserts) contributes to record high nighttime temperatures by trapping infrared radiation from the Earth.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-09-26T23:29:02.093" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12386" PostTypeId="1" CreationDate="2017-09-27T03:12:12.197" Score="6" ViewCount="103" Body="&lt;p&gt;I need to generate an all-zeros file as an input file for an Earth Systems model (DGVM) I'm using. I have a file with the same dimensions as the zero file. I have R and MATLAB and use a Fedora machine.&lt;/p&gt;&#xA;" OwnerUserId="11161" LastActivityDate="2017-09-27T03:12:12.197" Title="Generating netCDF file composed of zeros?" Tags="|matlab|netcdf|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12387" PostTypeId="1" AcceptedAnswerId="13813" CreationDate="2017-09-27T06:04:50.920" Score="8" ViewCount="1028" Body="&lt;p&gt;I am looking for Upper Air Observations (UAO) for Bay of Bengal region. I found NCEP ADP UAO dataset available in BUFR format. I am supposed to use UAO data in grib format only for the purpose of data assimilaion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any way, one can convert BUFR data into grib format?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks in advance&lt;/p&gt;&#xA;" OwnerUserId="11162" LastEditorUserId="5594" LastEditDate="2018-04-03T12:20:59.000" LastActivityDate="2018-12-17T14:37:57.180" Title="Conversion of BUFR format into grib" Tags="|data-formats|bufr|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12388" PostTypeId="1" CreationDate="2017-09-27T07:18:04.457" Score="6" ViewCount="102" Body="&lt;p&gt;With all the questions we've had through the years that have tied into weather models, plus all the sites around the web providing weather model data, it got me wondering: is there any table that summarizes the basic details of the major weather models?  Details like calculation methods, spatial resolution, calculation timestep, vertical grid type, regions covered, parameterizations, run hours (and when the output is typically available), operating organizations, perhaps even some basic skill scores.  It would seem such a link would be useful in answering many questions, and be of use to many in trying to better understand how the models work or perform.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd think the obvious spot would be Wikipedia, as they seem to have similar collaborative lists for all sorts of useful things, but all I found was the very limited &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_model#Domains&quot; rel=&quot;nofollow noreferrer&quot;&gt;list on the models page&lt;/a&gt;.  Likewise searched AMS Journals for NWP summary and similar terms to no avail.  Does such a resource exist!?!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-09-30T19:33:36.140" LastActivityDate="2017-12-13T13:26:50.723" Title="Does a table summarizing basic details of significant operational weather models exist?" Tags="|models|reference-request|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12389" PostTypeId="2" ParentId="12333" CreationDate="2017-09-27T13:18:10.387" Score="5" Body="&lt;p&gt;The AD 79 eruption is the last of four caldera forming events which reduced the heigth of Monte Somma. Their approximate timing is: ca. 18000 BP, ca. 8000 BP, ca. 3400 BP and AD 79. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Between 3400 BP and AD 79 it was about 1300 m high and height of the intact stratovulcano before the beginning of the caldera collapse was about 1900 m.&#xA;Note that while the original height can be extrapolated from the shape of the cone, the remaining height after individual events is not well constrained.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reference: Cioni, R., Santacroce, R., &amp;amp; Sbrana, A. (1999). Pyroclastic deposits as a guide for reconstructing the multi-stage evolution of the Somma-Vesuvius Caldera. Bulletin of Volcanology, 61(4), 207-222.&lt;/p&gt;&#xA;" OwnerUserId="2861" LastActivityDate="2017-09-27T13:18:10.387" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12391" PostTypeId="1" AcceptedAnswerId="12394" CreationDate="2017-09-28T06:32:54.907" Score="5" ViewCount="546" Body="&lt;p&gt;Why does the Guinea Current exist at all?  There are no similar currents in the Pacific or Indian Oceans and the Guinea Current also disappear during northern summers.  Why?&lt;/p&gt;&#xA;" OwnerUserId="8405" LastEditorUserId="111" LastEditDate="2017-09-29T12:51:29.923" LastActivityDate="2017-09-29T12:51:29.923" Title="Guinea Current existence in the Atlantic" Tags="|oceanography|ocean-currents|atlantic|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12392" PostTypeId="2" ParentId="9989" CreationDate="2017-09-28T10:26:14.557" Score="9" Body="&lt;p&gt;Basically the de facto best operational source would probably be the &lt;a href=&quot;http://www.spc.noaa.gov/faq/tornado/ef-scale.html&quot; rel=&quot;noreferrer&quot;&gt;Storm Prediction Center website&lt;/a&gt;.  They provide this table:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NtIUk.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NtIUk.png&quot; alt=&quot;fscale&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It caps out at EF5.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However it also true to note that the scale was developed to mirror the &lt;a href=&quot;https://en.wikipedia.org/wiki/Beaufort_scale&quot; rel=&quot;noreferrer&quot;&gt;Beaufort Scale&lt;/a&gt; into a range between the Hurricane Force on the Beaufort Scale and &lt;a href=&quot;https://www.grc.nasa.gov/www/k-12/airplane/mach.html&quot; rel=&quot;noreferrer&quot;&gt;Mach 1&lt;/a&gt;.  And as such, indeed in &lt;a href=&quot;https://ia800306.us.archive.org/0/items/nasa_techdoc_19720008829/19720008829.pdf&quot; rel=&quot;noreferrer&quot;&gt;Fujita's 1971 proposal of his scale&lt;/a&gt;, as well as in &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469%281981%29038%3C1511%3ATADITC%3E2.0.CO%3B2&quot; rel=&quot;noreferrer&quot;&gt;this 1981 journal article&lt;/a&gt; (which offers some additional interesting insight into the progression of understanding into tornadic wind speeds, plus alternative scales), Fujita lists the option:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/37ULUm.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/37ULUm.png&quot; alt=&quot;f6andabove&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, in the same papers, likely as his dataset expanded, he evolved his initial wording&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...the presumption that the occurrences of F6 or higher wind are&#xA;  extremely rare... [&lt;a href=&quot;https://ia800306.us.archive.org/0/items/nasa_techdoc_19720008829/19720008829.pdf&quot; rel=&quot;noreferrer&quot;&gt;1971 paper&lt;/a&gt;]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;into&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... because F6 or stronger tornadoes are not expected to occur on the&#xA;  earth, they will be called Inconceivable tornadoes should they ever&#xA;  occur. [&lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0469%281981%29038%3C1511%3ATADITC%3E2.0.CO%3B2&quot; rel=&quot;noreferrer&quot;&gt;1981 paper&lt;/a&gt;]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Very importantly, the Fujita scales are &lt;strong&gt;damage&lt;/strong&gt; scales, simply because it's very difficult to directly measure the speeds of a tornado. As such we base tornado ratings by analyzing the degree which it damaged objects; &lt;a href=&quot;http://www.spc.noaa.gov/faq/tornado/ef-scale.html&quot; rel=&quot;noreferrer&quot;&gt;SPC's Fujita scale page&lt;/a&gt; lists the 28 damage indicators currently available as of 2017. The highest wind speed matched with any of them, found when significant structural deformation is done to a high-rise building (over 20 stories tall), would only indicate an upper bound of 290 mph.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That does not indicate that wind speeds aren't higher than that, only that we have no structures that can withstand any higher wind speeds.  Thus there would not be any potential for an F6 rating unless building methods are substantially changed to withstand stronger speeds, those buildings became prevalent enough that engineering testing were done and were able to verify its strength, and then such an extreme tornado ever hit them.  Not something we're going to see anytime soon it appears.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So back to the question of whether tornadoes have winds stronger than those listed for an (E)F5?  Measurement of the wind speed appears our only real hope of noting such.  &lt;a href=&quot;https://en.wikipedia.org/wiki/In_situ&quot; rel=&quot;noreferrer&quot;&gt;In-situ&lt;/a&gt; instruments such as anemometers generally fail well before winds reach such speeds, and typical radars cannot offer the resolution to diagnose such speeds.  Only mobile Doppler radars offer much hope.  There are numerous issues with utilizing such measurements, such as the fact they scan significantly above the ground layer, their sampling areas\timescales that make analyzing suction vortices difficult, and they contain uncertainties due to Nyquist frequencies, variations in reflective objects, and statistical distributions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Such tornadoes are very rare to encounter.  But in the past couple decades we have indeed managed to attain a handful of close-proximity estimated measurements of strong tornadoes.  But I am not aware of any peak estimated wind speed reaching beyond the (E)F5 range.  Here are the most notable ones I'm aware of:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/full/10.1175/WAF-D-14-00026.1&quot; rel=&quot;noreferrer&quot;&gt;May 31, 2013 El Reno, OK: 135 m/s (302 mph)&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/BAMS-88-1-31&quot; rel=&quot;noreferrer&quot;&gt;May 3, 1999 Bridge Creek, OK: 135 m/s (302 mph)&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/full/10.1175/WAF-D-14-00026.1&quot; rel=&quot;noreferrer&quot;&gt;May 24, 2011 El Reno, OK: 132.1 m/s (295 mph)&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0493%281993%29121%3C2200%3ADRWSOS%3E2.0.CO%3B2&quot; rel=&quot;noreferrer&quot;&gt;April 26, 1991 Red Rock, OK: (268-280 mph)&lt;/a&gt;  &lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/MWR-2855.1&quot; rel=&quot;noreferrer&quot;&gt;May 30, 1998 Spencer, SD: (264 mph)&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;May 9, 2016 Sulphur, OK: EF4 or EF5 measurements (based on preliminary communication)  &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So, long story short:&lt;br&gt;&#xA;&lt;strong&gt;While (E)F6 tornadoes may not be impossible, and the categorization does theoretically exist... in practicality, there is no need for such a value, as the damage would be complete whether in an (E)F5 or (E)F6+.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-09-29T07:09:20.723" LastActivityDate="2017-09-29T07:09:20.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12394" PostTypeId="2" ParentId="12391" CreationDate="2017-09-28T14:47:26.357" Score="3" Body="&lt;p&gt;The Guinea Current is in &lt;a href=&quot;https://en.wikipedia.org/wiki/Geostrophic_current&quot; rel=&quot;nofollow noreferrer&quot;&gt;geostrophic balance&lt;/a&gt; with isopycnals sloping upwards towards the north. The current is not directly related to wind direction and magnitude and that makes rather especial. As many other eastern boundary currents, it is characterized by the presence of &lt;a href=&quot;https://en.wikipedia.org/wiki/Upwelling&quot; rel=&quot;nofollow noreferrer&quot;&gt;coastal upwelling&lt;/a&gt; (Bakun, 1978), which delivers nutrients to the surface waters and results in increased primary production.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JYMGz.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JYMGz.gif&quot; alt=&quot;oceancurrents.rsmas&quot;&gt;&lt;/a&gt; Source: &lt;a href=&quot;http://oceancurrents.rsmas.miami.edu/atlantic/guinea.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;RSMAS&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Guinea Current is connected with the &lt;a href=&quot;https://en.wikipedia.org/wiki/Equatorial_Counter_Current&quot; rel=&quot;nofollow noreferrer&quot;&gt;North Equatorial Counter Current&lt;/a&gt; (NECC) and in fact it can be considered the eastern continuation of the &lt;a href=&quot;http://oceancurrents.rsmas.miami.edu/atlantic/north-equatorial-cc.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NECC&lt;/a&gt;. The seasonal variations in the position of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Intertropical_Convergence_Zone&quot; rel=&quot;nofollow noreferrer&quot;&gt;Intertropical Convergence Zone&lt;/a&gt; affect the connection between NECC and Guinea Currents. The Guinea Current is also connected to the Canary Current flowing southward along the African coast. In this sense, the Guinea Current is at least partially related to the Indian and Pacific Equatorial Counter Currents. The difference is that there is no long stretch of coast parallel to the Equator in those oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;RSMAS &lt;a href=&quot;http://oceancurrents.rsmas.miami.edu&quot; rel=&quot;nofollow noreferrer&quot;&gt;ocean currents project&lt;/a&gt; provides a &lt;a href=&quot;http://oceancurrents.rsmas.miami.edu/atlantic/guinea.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;complete description&lt;/a&gt; of the main characteristics of the Guinea Current with references.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, the Guinea Current does not disappear during the northern summer. In fact, there is a tendency for the current to intensify (check Figure 3 in Bakun, 1978 for instance).&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.readcube.com/articles/10.1038/271147a0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bakun, A., 1978&lt;/a&gt;. Guinea current upwelling. Nature, 271(5641), pp.147-150.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="111" LastActivityDate="2017-09-28T14:47:26.357" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12395" PostTypeId="1" CreationDate="2017-09-28T19:11:08.497" Score="-1" ViewCount="84" Body="&lt;p&gt;I'm looking over different historical storms in the Atlantic, from Tropical Storms, to category 5 hurricanes. It made me wonder what the worst case scenario storm would look like, what path (and when) a storm could take to create the most damage. So how would such a mega-storm play out? Let's say you are a mad scientist with a hurricane machine. You can control the speed and direction of the storm as it progresses from depression to a tropical storm to a Category 1 storm to a Category 5. Walk me through the path, timeframe, and severity of it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Idk if there’s some sort of online simulator that allows you to draw a storm path and have it calculate the relative severity of it, but that would be awesome for this. I've seen some simulators, and this one flash game, but none that allow you to control direction or speed.&lt;/p&gt;&#xA;" OwnerUserId="11169" LastEditorUserId="11169" LastEditDate="2017-09-28T19:20:02.767" LastActivityDate="2017-09-28T23:19:09.890" Title="If you were to create the most devastating and powerful Atlantic Hurricane ever, what path would it take and how would the storm progress?" Tags="|meteorology|tropical-cyclone|" AnswerCount="1" CommentCount="1" ClosedDate="2017-09-29T03:29:24.503" ContentLicense="CC BY-SA 3.0" />
  <row Id="12396" PostTypeId="1" AcceptedAnswerId="12397" CreationDate="2017-09-28T20:28:45.300" Score="7" ViewCount="10325" Body="&lt;p&gt;People at the equator get to bask in more sunlight than Santa Clause and other inhabitants of the arctic regions. Not quite as pronounced, but they get more than me too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is the sunlight more intense closer to the equator and less intense farther away from it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I posted this question, I was not thinking about the possible ambiguities, such as &quot;Are you talking about the exposure across a surface area with some non-perpendicular angle to the sun,&quot; or &quot;Are you talking about the light gathered by an optic facing the sun?&quot; There is a difference. Since &quot;basking in sunlight&quot; was the example use case, let us assume exposure across a surface area which is lying on the ground.&lt;/p&gt;&#xA;" OwnerUserId="11171" LastEditorUserId="94" LastEditDate="2017-10-04T16:23:24.453" LastActivityDate="2017-10-04T16:23:24.453" Title="Why does the intensity of sunlight depend on your latitude?" Tags="|temperature|sun|light|equator|insolation|" AnswerCount="2" CommentCount="3" ClosedDate="2017-10-04T13:56:31.103" ContentLicense="CC BY-SA 3.0" />
  <row Id="12397" PostTypeId="2" ParentId="12396" CreationDate="2017-09-28T20:28:45.300" Score="14" Body="&lt;p&gt;As noted in the comments, this answer applies to things like sun-bathing and solar panels, but it does not apply so much to a specific point-receptor like an eyeball. If all objects in question are pointing directly at the sun, then the angle of incidence is equal for all of them and this answer does not apply.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For an optic facing its target, the amount of atmosphere that the light passes through is a very large influencer. At higher latitudes, the sun is not directly overhead, and so the light is not coming straight down through the path of least atmosphere. Instead, it comes in at an angle, passing through more of the atmosphere before it gets to you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For sun-bathers, solar panels, and the ground in general, the sunlight absorbed and reflected does depend very much on what is described in this answer. For that reason, more expensive solar panels are mounted on devices which alter their angle to face the sun for increased light exposure. And a sun-bather could likewise increase their exposure by mounting their platform at an angle. This is the direction the rest of the answer will take.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer is similar to the answer to some other questions, such as &quot;Why does the solar power intensity change with the season?&quot; and &quot;Why does the solar intensity change with the height of the sun in the sky (ie: with the time of day)?&quot;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;The very short, non-technical version (tl;dr)&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Each unit (think &quot;beam of sunlight&quot;) is spread over a larger area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That might not seem intuitive at first, but that is the answer in a nutshell. To see why, continue to the long version.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;The mechanics of the situation&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The sun is huge, but at great distances it can be thought of as a &lt;strong&gt;point-source&lt;/strong&gt; of light. The sun emits light in every direction, so its energy, the electromagnetic radiation, can be thought of as beams of sunlight coming out from it in every direction. However, the farther away you get, the fewer of those sunlight beams cross your path, and if you get far away you can see, from the below illustration, that the lines which cross your path are becoming ever more parallel and &lt;strong&gt;directional&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OWGhu.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OWGhu.png&quot; alt=&quot;Sun as point source of light&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the sun is &lt;em&gt;very, very, very&lt;/em&gt; far away - many millions of miles (and kilometers) away. At this distance, the electromagnetic radiation is all arriving at roughly parallel trajectories. That is, the light reaching us can be viewed as coming from a &lt;strong&gt;directional light source&lt;/strong&gt;; it's all going in the same direction. You will see my crude illustration of that coming up after the next picture, but first...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When this happens, the angle at which the light arrives relative to the surface of the earth that it is arriving at, known as the &lt;strong&gt;angle of incidence&lt;/strong&gt;, is what makes all the difference here. In the image below, we have light arriving from the left, perhaps from a flashlight(s), and two objects we want to see. The surface of the object below will be illuminated more, but the surface of the object above will be illuminated less.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YdreY.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YdreY.png&quot; alt=&quot;Surface area illumination of triangles at different angles of incidence&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Notice the object above gets 2 units of light to illuminate its entire surface, whereas the object below gets 5 units of light for its surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looked at another way, the object above has to spread 2 units of light across its entire surface, where the object below gets that same amount of light concentrated on only a smaller part of it.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Now back to Earth&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;We see the same thing happen. Notice in the below picture that I have labeled the diameter of the area covered by my arbitrary unit of light. The distance is literally measured in image pixels. Near the equator, 1 unit of light illuminates 27 pixels, but closer to the pole the same amount of light needs to be spread out over 61 pixels of Earth's surface, so it's illuminated less.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7ndE1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7ndE1.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And that is the answer to the question, and the related questions mentioned in my introduction.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Some specific calculations&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The specific ratio of illumination difference for the two areas in the above image would be (&lt;em&gt;approximately&lt;/em&gt;) simply the division of the two numbers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The area closer to the pole is getting &lt;code&gt;27/61&lt;/code&gt; as much light per longitudinal unit cross-section (a north/south strip of land) as the area closer to the equator, or 0.4426 times as much light.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or, in the other direction, the area at the equator is getting &lt;code&gt;61/27&lt;/code&gt; as much light, or 2.26 times as much light. So the equator area is getting more than twice as much light.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can easily see from this why the sun might appear very much brighter or dimmer depending on the angle, and therefore depending on the latitude. This also explains the temperature difference: the equator is receiving a lot more energy, so it gets hotter.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Answer applied to seasons&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;I said earlier that this also answers the question about the illumination change for the seasons. The only extra bit of information that we need to understand that is this: Earth's pole around which it revolves is not perfectly perpendicular to the direction that the light is arriving from. Because of this, the specific angle changes as Earth orbits around the sun. The orbit around the sun takes a year (That's what a year &lt;em&gt;is&lt;/em&gt;, by definition), so this change of angle over time has a yearly cycle during which the angle of incidence (the fancy term from above again, which just means &quot;the difference of angle of the light to the object it is hitting&quot;) changes. This change is large enough to further change the sunlight that we receive, in the exact same way as discussed above.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Further notes about temperature&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Just like before, this also affects temperature. The temperature, however, cannot be calculated by a simple ratio of area coverage. The temperature is affected by multiple other complicated systems. One of the major temperature influencers is the &lt;strong&gt;weather&lt;/strong&gt;. Another of which is the difference between energy absorbed and energy lost (a physics thing: Earth is not a &quot;&lt;strong&gt;black body&lt;/strong&gt;&quot; radiator).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Weather affect on temperature is very complicated and would require its own post much longer than this one, but to sum it up super succinctly: stuff like the wind and rain and such change the temperature and also move it around.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The physics black-body thing likewise would require its own long post, but again, super succinctly: Earth is also putting out its own energy into space at the same time it is receiving energy from the sun, and the affect this has on temperature is a fine balancing act. Once that balancing act tips to one side, the temperature swings way over in that direction: during the spring when temps are rising the energy absorption is enough higher than the energy radiation that the temperature rises, and the opposite is true for autumn when temps are falling.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The above descriptions for both weather and block-body radiation are way oversimplified.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;That's it&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;And now the answer applies fully to seasonal changes as well, and it applies not only to illumination but also to temperature. I will leave it as an exercise for the reader to think about the daily affect (Why is it so much easier to look at the sun when it is low on the horizon just before it sets?)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And, as stated before, there are other influencers for these things; this just happens to be the biggest one.&lt;/p&gt;&#xA;" OwnerUserId="11171" LastEditorUserId="11171" LastEditDate="2017-10-02T15:17:15.300" LastActivityDate="2017-10-02T15:17:15.300" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12398" PostTypeId="2" ParentId="12395" CreationDate="2017-09-28T23:19:09.890" Score="2" Body="&lt;p&gt;Asking this is a bit like asking something like &quot;which young athlete should a sports team draft/sign to have the best results&quot;...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;There are hints towards which ways to go&lt;/strong&gt;:&lt;br&gt;&#xA;(best physical skillsets and athleticism) / (&lt;strong&gt;a corridor of very warm SST, limited land, low-ish shear&lt;/strong&gt;)&lt;br&gt;&#xA;&lt;strong&gt;But identifying the optimal situation is incredibly impossible, as most of it comes down to evolution factors that are nuanced&lt;/strong&gt;&lt;br&gt;&#xA;(how the player develops) / &lt;strong&gt;(subtle interactions with surrounding systems, inner-core evolution, how winds channel over land and impact key buildings&lt;/strong&gt;) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the end, we're not even that great at forecasting how a storm will intensify or weaken in the upcoming hours (&lt;a href=&quot;http://www.nhc.noaa.gov/verification/verify5.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;much worse at it than at track forecasts, and not seeing significant improvements&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The best hints are probably found in past category 5 hurricanes and top supertyphoons... generally they've had fairly steady motion (to prevent overturning the warm ocean waters), had well positioned &lt;a href=&quot;http://webcms.colostate.edu/tropical/media/sites/111/2016/10/392_Chen.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;outflow channels&lt;/a&gt;, and formed and had subsequent tracks over great amounts of warm water and away from significant land/mountainous terrain.  Generally most have undergone rapid intensification.  But it's very difficult to maintain anything near &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_Category_5_Atlantic_hurricanes&quot; rel=&quot;nofollow noreferrer&quot;&gt;category 5 winds&lt;/a&gt; on Earth for very long even in ideal conditions; &lt;a href=&quot;https://en.wikipedia.org/wiki/Eyewall_replacement_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;eyewall replacement cycles&lt;/a&gt; typically cause fluctuations in even the most perfect storms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mad scientist would think that maybe one could just weave storms around warm water regions for long periods of time carefully, and surely a stronger storm could eventually develop.  But a storm doesn't just turn at whim, but based upon the winds brought from the larger storm systems around it.  And the changes of those &quot;background&quot; winds don't just alter the storm's direction, but change the shear and instability in the storm itself.  It's nowhere near as simple as just flipping a switch, even ideally.  Plus the top ocean temperatures often take &lt;a href=&quot;http://www.rsmas.miami.edu/blog/2012/10/22/what-happens-underwater-during-a-hurricane/&quot; rel=&quot;nofollow noreferrer&quot;&gt;weeks or more to recover after a strong storm passes&lt;/a&gt;, so you'd likely have to be an amazing navigator like &lt;a href=&quot;https://www.youtube.com/watch?v=kZr8sR9Gwag&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can get a rough estimate of the possible regions in play using the &lt;a href=&quot;https://emanuel.mit.edu/limits-hurricane-intensity&quot; rel=&quot;nofollow noreferrer&quot;&gt;maximum potential intensity theory from Dr. Kerry Emanuel&lt;/a&gt;, which analyzes the physical limitations to the heat engine process that hurricanes are.  &lt;a href=&quot;https://emanuel.mit.edu/limits-hurricane-intensity&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here are real-time maps of these values&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But in the end, any game allowing you to try to create the perfect storm would be like trying to manipulate the future to your wishes: &lt;a href=&quot;https://en.wikipedia.org/wiki/The_Butterfly_Effect&quot; rel=&quot;nofollow noreferrer&quot;&gt;good luck&lt;/a&gt;!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2017-09-28T23:19:09.890" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12399" PostTypeId="1" CreationDate="2017-09-28T23:55:25.043" Score="4" ViewCount="2750" Body="&lt;p&gt;Can someone please explain the difference between sedimentary facies and formations?&lt;/p&gt;&#xA;" OwnerUserId="11172" LastActivityDate="2017-09-30T05:01:38.270" Title="Geology: facies v. formations" Tags="|geology|sedimentology|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12400" PostTypeId="2" ParentId="12399" CreationDate="2017-09-29T07:39:43.600" Score="3" Body="&lt;p&gt;A formation is a unit of stratigraphy. It refers to a set of sedimentary layers which are somehow distinct from those above and below them in the stratigraphic sequence. This may be because they have a different lithology, different sedimentary structures, or different fossil assemblages, or something else entirely.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A sedimentary facies is a set of rocks which where deposited in the same sedimentary environment. Typically deposition in this environment will leave behind distinctive signatures in the rock which can help to identify the environment of deposition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Within a formation the facies can change both vertically and laterally. Equally, the facies may not change at all over several formations.&lt;/p&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2017-09-29T07:39:43.600" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12401" PostTypeId="1" AcceptedAnswerId="12403" CreationDate="2017-09-29T07:43:54.497" Score="2" ViewCount="105" Body="&lt;p&gt;The surface of the ground at night cools down because of outgoing long-wave radiation. In my understanding the cooling of the surface also causes cooling of the adjacent air. If the air contains enough water vapor, dropping of the temperature causes condensation of liquid water droplets and formation of fog.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In my region (Central Europe near 50°N) in winter, stratus clouds can be observed much more often than fog. Typically the base of the stratus cloud is 100 meters or higher above ground surface and the thickness of the stratus is several hundred meters. What puzzles me is the &quot;empty&quot; layer between the ground surface and the cloud base. Why does the stratus cloud often not reach all the way to the ground? What factors determine the stratus cloud base height?&lt;/p&gt;&#xA;" OwnerUserId="11176" LastActivityDate="2017-09-29T12:45:26.190" Title="Why a stratus cloud does not always reach all the way to the ground?" Tags="|clouds|humidity|atmospheric-radiation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12403" PostTypeId="2" ParentId="12401" CreationDate="2017-09-29T12:45:26.190" Score="2" Body="&lt;p&gt;I'd postulate that this is purely temperature-driven. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the dew point temperature of your 'empty' layer is not reached then the water vapour will not condense to form fog. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do you observe the clouds there during the day? Thin clouds such as stratus primarily transmit incoming solar radiation whilst trapping some of the outgoing long-wave radiation, thus insulating the air between the ground and the base of the cloud layer and preventing dew point temperature being reached. &lt;/p&gt;&#xA;" OwnerUserId="10710" LastActivityDate="2017-09-29T12:45:26.190" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12404" PostTypeId="2" ParentId="12399" CreationDate="2017-09-29T14:50:36.397" Score="1" Body="&lt;p&gt;The definitions are relatively similar. Both are distinct layers are of rock, but they do have their distinctions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Formations&lt;/strong&gt; are one of the larger category of layers, having several subdivisions (members, groups, ect), and formations tend to be more widespread in occurrence and identifiable across many outcrops.  They are laterally continuous.  Usually a formation refers to some linked structures or environments, like a group of volcanic events, or a sequence of floodplain deposits. Parts (members, groups) of a formation are often distinct but the collection of related ones is called a formation. So think of it as a widespread identifiable layer or sequence of layers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Morrison_Formation#Geologic_history&quot; rel=&quot;nofollow noreferrer&quot;&gt;morrison&lt;/a&gt; formation in North America is a classic example, it's a collection of layers of sediment spread over most of the central US from the Jurassic, it varies in color and grain size but is all fluid deposited sediment originating from the same time period.  It is the floodplains and drainage that formed as the western interior seaway shrank.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Facies&lt;/strong&gt; on the other hand are basically any distinct layer or any size, where you can tell the difference between them somehow. Usually facies are defined by what is being studied, a formation is always the same but the same exact outcrop may have different facies depending on what you are studying. Say petroleum facies defined by hydrocarbon content, or seismic facies defined by sonar reflectivity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For an analogy, think of a library, any book by the same author would be a formation, while the individual physical books would be facies, some facies (books) may be a single formation (author only wrote one book), and others may only be a small part of a larger formation. If you go to another library you can find more by that author (formation) but they will not be the same &lt;em&gt;exact&lt;/em&gt; book/s (facies) although they may be copies of the same book. It's not a perfect analogy but it helped me when I was a student. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2017-09-30T05:01:38.270" LastActivityDate="2017-09-30T05:01:38.270" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12405" PostTypeId="2" ParentId="12399" CreationDate="2017-09-29T15:59:34.410" Score="3" Body="&lt;p&gt;A &lt;strong&gt;&quot;sedimentary facies&quot;&lt;/strong&gt; is just a descriptive term. For example all rocks (anywhere in the world) that have similar characteristics (e.g. mineralogy, color, grain size distribution, sedimentary structures, fractures, etc) can be considered to be of the same facies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A &lt;strong&gt;&quot;formation&quot;&lt;/strong&gt; is a named rock unit in a specific place.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, let's say that in Canada, geologists have named some rock units:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Formation E - top&lt;br&gt;&#xA;Formation D&lt;br&gt;&#xA;Formation C&lt;br&gt;&#xA;Formation B&lt;br&gt;&#xA;Formation A - bottom&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And in Australia, they have named some other rock units&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Formation Z - top&lt;br&gt;&#xA;Formation Y &lt;br&gt;&#xA;Formation X&lt;br&gt;&#xA;Formation W&lt;br&gt;&#xA;Formation V - bottom&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, Formation X in Australia and Formation A in Canada have very similar characteristics (as mentioned above). You could say that both of those formations are of the same facies. This is helpful because if, by some additional means, you figure out what was the geologic process that created Formation A, you may have a very good hypothesis on the geologic process that created Formation X.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's say that the geologic process that created Fromation A and Formation X was a river (i.e. fluvial) system, then it is common for people to call any rock elsewhere, with similar characteristics as Formations A and X, a rock of &quot;fluvial facies&quot;. That is a short way of saying &quot;a rock with many of the characteristics of other rocks that are interpreted as being created by a fluvial system&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although this is technically an incorrect use the term &quot;facies&quot; because you are adding an interpretation to what is supposed to be a purely descriptive concept, people do it all the time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, once you know what certain common facies look like (e.g. fluvial facies, delta facies, etc), it helps when trying to divide an entire rock section of a specific area into formations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A real example of this is the Bouma facies (commonly called the Bouma &quot;sequence&quot; for historical reasons). Basically, some guy called Bouma noticed that many rocks around the world that had been interpreted as being formed by turbidity currents had similar characteristics:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LT6vA.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LT6vA.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is extremely helpful because it allows a quick and robust interpretation of geologic processes if a similar facies is found in another rock around the world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PYwJH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PYwJH.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, experimental geologists will then try to recreate the set of characteristics in a laboratory flume experiment in order to gain even more insight as to the necessary flow conditions that had to have taken place.&lt;/p&gt;&#xA;" OwnerUserId="4636" LastActivityDate="2017-09-29T15:59:34.410" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12407" PostTypeId="2" ParentId="12372" CreationDate="2017-09-30T09:30:52.553" Score="7" Body="&lt;p&gt;There are several questions here, I'm only focusing on the question regarding sea level in the past as per the title question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short, global mean sea level (GMSL) has been both lower and higher than present in the past. As recently as the last glacial maximum around 25,000 years ago GMSL was around 120m below present as much of the water was held on land as ice. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, GMSL doesn't really exist because sea level is not level, but is a useful way of summarising global trends. What people living in coastal areas experience is relative sea level (RSL), which is defined as the mean level of the sea surface relative to the level of the land. There are two key components affecting RSL: isostasy and eustasy. Put simply, isostasy refers to the vertical position or motion of the land (the Earth's solid crust sits on a molten mantle and is subject to vertical displacement from its equilibrium state governed by the balance of overburden pressures  i.e. a concentration of mass on land causes subsidence of the land beneath it whilst uplifting the land extending beyond the focus of the mass. Eustasy refers to a uniform, global change in sea level caused by fluctuations in the balance between water held on land (usually as ice) and in the oceans, or by a change in the capacity of ocean basin (usually tectonically related). RSL can vary considerably from GMSL (unsurprising since this is a mean measurement). For example (I'll use a British example here since that's where I'm from), at the last glacial maximum ice sheets covered the northern part of the British Isles from Scotland down to around the middle of England  (the exact southern extent is still debated in the scientific literature). The overburden of this ice effectively turned the British Isles into a giant see-saw with the land in northern part subsiding and the southern part uplifting. The effects of this are still felt today long after the ice has melted (and contributed a eustatic sea level component) as the land level readjusts to its equilibrium state( glacio-isostatic adjustment); the land in Scotland is rising and the land in the south of England is subsiding. So, whilst is true that globally sea level is rising  (at a rate of around  3.2 mm/yr), when combined with local land level changes then some places actually currently experience a sea level fall (in Scotland this is up to -1.5mm/yr) whilst in regions of isostaic subsidence the rate of sea level rise can be considerably greater than GMSL. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since you mentioned gravity in your question I'll breifly introduce another curious component  (there are others,see reference below) which results in globally  non-uniform sea level changes. We are not experiencing a lower level of gravity  (gravity is a constant).  The amount of gravity that something possesses is proportional to its mass and distance between it and another object. On Earth mass is obviously not evenly distributed, with each location on the planet experiencing a different mass-dependant   perturbation of the gravitational field. So for example, as an ice sheet forms and grows  mass increases which results in a gravitational perturbation which attracts the ocen toawrds the ice sheet but as the ice sheet melts and the gravitational perturbation reduces that water that was previously drawn towards the ice mass is redistributed in distant locations from the ice mass. This (counterintuitively) means that the greatest rates of sea level rise as a consequence of Greenland melt are actually experienced in the Southern Hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this serves as a useful introduction. I would usually include more references but I'm writing this on my phone right now whilst travelling on a train. One key reference,which is written in a non-technical style, worth checking out is : &#xA;Sea level is not level : The case for a new approach to predicting UK sea-level rise. / Gehrels, Willem Roland; Long, A.J.&#xA;In: Geography Compass, Vol. 93, No. 1, 01.03.2008, p. 11-16.&lt;/p&gt;&#xA;" OwnerUserId="10710" LastEditorUserId="10710" LastEditDate="2017-09-30T16:17:34.180" LastActivityDate="2017-09-30T16:17:34.180" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12408" PostTypeId="2" ParentId="12388" CreationDate="2017-09-30T19:33:19.553" Score="1" Body="&lt;p&gt;Happened to come across &lt;strong&gt;&lt;a href=&quot;http://www.nhc.noaa.gov/modelsummary.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;a very fair list&lt;/a&gt;&lt;/strong&gt; at the National Hurricane Center website giving the details of the models and ensembles they employ operationally.  Had seen the basic list of what the models are &lt;a href=&quot;http://derecho.math.uwm.edu/models/models.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;many other places&lt;/a&gt;, basically almost anywhere the &lt;a href=&quot;http://ftp.nhc.noaa.gov/atcf/README&quot; rel=&quot;nofollow noreferrer&quot;&gt;A-deck&lt;/a&gt; &quot;spaghetti models&quot; are shown... but not giving the details on topics like data assimilation/resolution/ensemble methods/cycles, which much better answer some of my question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's not perfect, both because it lacks a few of the requested details, and also because it excludes models like the NAM, HRRR, and FIM that aren't particularly applied in TC situations... but it's far better than anything I've ever come across!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;hr&gt;&#xA;I've also came across &lt;a href=&quot;https://www.wmo.int/pages/prog/www/DPFS/ProgressReports/&quot; rel=&quot;nofollow noreferrer&quot;&gt;a page of some old reports&lt;/a&gt; from the WMO that may offer a small bit of insight into what modelss are used around the world, and the &lt;a href=&quot;http://worldweather.wmo.int/en/home.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;WMO main weather page&lt;/a&gt; offers links to each country's meteorological office, where such data may well be found.  For instance, it appears that Argentina's &lt;a href=&quot;http://www.smn.gov.ar/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Servicio Meteorológico Nacional&lt;/a&gt; runs an ETA model for their region.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-12-13T13:26:50.723" LastActivityDate="2017-12-13T13:26:50.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12409" PostTypeId="1" CreationDate="2017-09-30T19:46:24.657" Score="1" ViewCount="121" Body="&lt;p&gt;See this &lt;a href=&quot;https://www.google.com/maps/place/Massanutten,+VA/@38.7258961,-78.9869216,18114a,35y,88.04h,73.65t/data=!3m1!1e3!4m5!3m4!1s0x89b48b1717db1fdb:0x81b45cb6bad92b11!8m2!3d38.4095701!4d-78.7378004&quot; rel=&quot;nofollow noreferrer&quot;&gt;aerial view from google maps&lt;/a&gt;. Massanutten is in the foreground, as straight as an arrow. The Appalachians are on either side, looking like more typical mountains, zig-zagging with outcroppings in every direction. I was lucky enough to find &lt;a href=&quot;https://vimeo.com/14195770&quot; rel=&quot;nofollow noreferrer&quot;&gt;this video&lt;/a&gt; on exactly this topic, but I have zero geology knowledge, so it went completely over my head. Can anyone explain it in very simple terms?&lt;/p&gt;&#xA;" OwnerUserId="11192" LastActivityDate="2017-10-01T01:53:07.187" Title="Why is Massanutten mountain so dramatically different than surrounding mountains?" Tags="|mountains|mountain-building|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12411" PostTypeId="1" CreationDate="2017-10-01T01:24:12.427" Score="3" ViewCount="2143" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tCuAw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tCuAw.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I created this climate map based on a simplified Koppen Climate Classification map (shown below). In this scenario Australia is moved 10 degrees of latitude further south and the Lake Eyre basin is filled (shown in map.) Is this an accurate representation of the resulting climate?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/JLOHH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JLOHH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11195" LastEditorUserId="11195" LastEditDate="2017-10-01T10:24:42.107" LastActivityDate="2017-10-01T10:24:42.107" Title="Is this an accurate simulation of a further south Australia with a filled lake Eyre?" Tags="|meteorology|atmosphere|climate|humidity|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12412" PostTypeId="2" ParentId="12409" CreationDate="2017-10-01T01:53:07.187" Score="2" Body="&lt;p&gt;If you look a wider view from &lt;a href=&quot;https://www.google.com/maps/place/Massanutten,+VA/@38.8967113,-79.0539759,103984m/data=!3m1!1e3!4m5!3m4!1s0x89b48b1717db1fdb:0x81b45cb6bad92b11!8m2!3d38.4095701!4d-78.7378004&quot; rel=&quot;nofollow noreferrer&quot;&gt;above&lt;/a&gt; and a bit to the west, you will notice Massanutten is not that straight nor is it unique most of the surrounding mountains are the same, especially to west. Basically you camera is pointed in exactly the wrong direction to see the other mountains. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;on a geologic map it becomes even more obvious. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/xd5L4.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xd5L4.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A false color which hides the difference in plant life makes it even easier.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/oDaWu.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oDaWu.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can picture the appalachians as a flat section of rock that has been compressed like an accordion east to west, that's why they are more or less parallel, but not perfectly parallel becasue the rock is not completely uniform in strength or hardness. Plus the compression has a bit of a curve to it making it even less uniform. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2017-10-01T01:53:07.187" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12413" PostTypeId="1" CreationDate="2017-10-01T19:31:20.427" Score="4" ViewCount="91" Body="&lt;p&gt;I'm not sure if this is the right place for this question, but here goes...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm reviewing literature regarding effectiveness of wastewater treatment techniques. When considering faecal coliforms concentrations are generally presented in terms of most probable number per volume or per mass, typically MPN/100mL or MPN/g. Due to the scales involved these are often in scientific notation.&#xA;The reduction in concentration due to treatment is then presented as a log factor, i.e. reduction from $6\times10^{10}MPN/100mL$ to $3\times10^{4}MPN/100mL$ is hence $log(2\times10^{6}) = 6.30$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One paper that I'm reading presents the following (amongst several similar examples):&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;influent Faecal coliform conc. = &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;$1.43\times10^{5.1}\pm0.6\times10^{0.25}MPN/100mL$ &lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;effluent Faecal coliform conc. = &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;$5.1\times10^{2.5}\pm3.7\times10^{0.7}MPN/100mL$ &lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;resultant log reduction = 2.18&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;1: Has anyone encountered data presented like this before?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2: Is there some way of calculating reduction that results in 2.18 (I get 2.05)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I contacted the author re. the data presentation, to be told: &quot;While showing your results you can follow any kind of mode to compare your results. It is up to you that how you are interpretating your data. But, whenever you showing these data it should not be in decimal place it would be in 10 to the power. And that superscript can be in decimal.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;JS&lt;/p&gt;&#xA;" OwnerUserId="11197" LastEditorUserId="11248" LastEditDate="2017-10-09T18:47:11.787" LastActivityDate="2017-10-09T18:47:11.787" Title="Present results as log data" Tags="|pollution|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="12414" PostTypeId="1" CreationDate="2017-10-02T05:39:59.270" Score="2" ViewCount="832" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/49tdG.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/49tdG.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;**Tooth was found in Baltic Sea, near Lithuanian coast, **&lt;/p&gt;&#xA;" OwnerUserId="11199" LastActivityDate="2023-01-15T16:54:46.267" Title="Who can it belong to? fossil tooth" Tags="|fossils|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12416" PostTypeId="2" ParentId="12372" CreationDate="2017-10-02T15:13:53.773" Score="2" Body="&lt;p&gt;&quot;Does that mean the earth's sea-level was much lower than it is now? If this is true, then are we experiencing a lower level of gravity?&quot;\&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There were indeed periods in the Earth's past when sea-level was was lower than what it is now. One of the main reasons for this is the Earth's glacial-interglacial cycles. During an ice-age, there are huge ice-sheets on the continents. The water for this ice comes from the oceans, thus the sea level gets lower when there is a lot of ice on the land. &lt;/p&gt;&#xA;" OwnerUserId="639" LastActivityDate="2017-10-02T15:13:53.773" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12417" PostTypeId="1" CreationDate="2017-10-02T16:32:00.543" Score="3" ViewCount="179" Body="&lt;p&gt;I need to simulate some ocean data on the south coast of France, near to Marseilles. Ideally I am looking for parameters such as wind direction, wind speed, significant wave height, peak wave period and the mean wave direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have been looking at the WW3 data on &lt;a href=&quot;http://polar.ncep.noaa.gov/waves/download.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://polar.ncep.noaa.gov/waves/download.shtml&lt;/a&gt; but the resolution for this area is only 0.5 degrees.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am looking for data of a higher resolution so I wanted to know if anyone knows of either:&#xA;- any place that stores this kind of data&#xA;- how to go about simulating my own WW3 data&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can get ASCAT data for the wind direction/wind speed but they don't provide the ocean wave parameters. &lt;/p&gt;&#xA;" OwnerUserId="7367" LastEditorUserId="2470" LastEditDate="2017-10-02T23:36:21.567" LastActivityDate="2018-01-31T19:47:21.013" Title="Wavewatch III data" Tags="|models|wind|waves|database|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12418" PostTypeId="1" AcceptedAnswerId="12446" CreationDate="2017-10-03T02:39:36.350" Score="7" ViewCount="362" Body="&lt;p&gt;The volume transport of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Florida_Current&quot; rel=&quot;nofollow noreferrer&quot;&gt;Florida Current&lt;/a&gt; (one of the parts of the Gulf Stream) is measured using an underwater cable. What are the processes that allow for these measurements? How can we obtain measurements from a cable? Where else is this technique applied?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ofpSP.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ofpSP.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;sup&gt;Image from &lt;a href=&quot;http://oceancurrents.rsmas.miami.edu/atlantic/florida.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://oceancurrents.rsmas.miami.edu/atlantic/florida.html&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2017-10-10T15:38:33.653" LastActivityDate="2017-10-10T15:38:33.653" Title="What mechanism is used to measure ocean currents from cables?" Tags="|oceanography|measurements|ocean-currents|atlantic|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12419" PostTypeId="2" ParentId="12418" CreationDate="2017-10-03T08:07:51.300" Score="3" Body="&lt;p&gt;The most likely explanation is that a device similar to a &lt;a href=&quot;http://www-g.eng.cam.ac.uk/whittle/current-research/hph/hot-wire/hot-wire.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;hot wire anemometer&lt;/a&gt; has been used; but one that has been designed to be used in oceans. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A hot wire anemometer is basically an electric heater that has been calibrated. The heating element radiates heat into a surrounding medium, depending on the design and  construction of the anemometer, either air or water. The greater the heat loss, the greater the flow of the cooling medium over the anemometer element.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By calibrating the anemometer it is possible to determine the velocity of the medium, in this case ocean current, over the anemometer and from that it is possible to determine the volume flow rate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://iopscience.iop.org/article/10.1088/0022-3735/5/12/009/pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Solid state devices&lt;/a&gt;, using silicon transistor sensors have also been developed to measure ocean currents.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-10-03T08:07:51.300" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12420" PostTypeId="2" ParentId="9762" CreationDate="2017-10-03T08:56:03.227" Score="3" Body="&lt;p&gt;A crater is what you can see on the top of a volcano and the vent is the tube leading to the crater. Sometimes fissures on the volcano can make a secondary volcanic cone if a volcano is a long periodic one which allows the magma to go sideways where the resistance might be lower.&#xA;&lt;a href=&quot;https://golearngeo.wordpress.com/2010/02/24/volcano-features/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://golearngeo.wordpress.com/2010/02/24/volcano-features/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="5052" LastEditDate="2019-06-01T04:56:26.593" LastActivityDate="2019-06-01T04:56:26.593" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="12422" PostTypeId="2" ParentId="12417" CreationDate="2017-10-03T17:56:21.193" Score="1" Body="&lt;p&gt;Look at the answer to &lt;a href=&quot;https://opendata.stackexchange.com/questions/10154/sources-of-weather-data/10155&quot;&gt;https://opendata.stackexchange.com/questions/10154/sources-of-weather-data/10155&lt;/a&gt; under the 'The &quot;raw&quot; data as it comes into NOAA from airports, surface weather stations, boats, and buoys'. Is that what you seek?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that I couldn't get your link to download, though this may just be a temporary NOAA glitch.&lt;/p&gt;&#xA;" OwnerDisplayName="user967" LastActivityDate="2017-10-03T17:56:21.193" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12423" PostTypeId="2" ParentId="12396" CreationDate="2017-10-03T19:36:35.020" Score="0" Body="&lt;p&gt;Both solar altitude above the horizon and length of day influence total received solar energy. On December 21st both decrease with increasing latitude (in the Northern hemisphere), both dropping to zero at the Arctic Circle. On June 21st solar altitude above the horizon decreases with increasing latitude north of the Tropic of Cancer, but length of day increases with increasing latitude. Thus on June 21st maximum total daily solar energy is received at latitude 30 to 35 degrees North assuming average cloudiness, and at latitude 35 to 40 degrees North with clear skies. That's one reason why Death Valley gets so hot in summer --- it is at or near the latitude of maximum total daily solar energy receipt considering both sun altitude above the horizon and length of day.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-10-03T19:36:35.020" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12424" PostTypeId="1" CreationDate="2017-10-03T20:10:31.567" Score="12" ViewCount="2600" Body="&lt;p&gt;Where is the true source of the River Amazon?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Searching &lt;a href=&quot;https://en.wikipedia.org/wiki/Amazon_River&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;, it suggests the River Apurímac has traditionally been considered the source.  However, &lt;a href=&quot;https://www.google.com/search?q=source%20of%20the%20amazon%20river&amp;amp;ie=utf-8&amp;amp;oe=utf-8&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google says&lt;/a&gt; it is the River Mantaro. In other places it is suggested it is the Nevado Mismi.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So which of these (if any) is the true source of the Amazona? Where is the river &lt;em&gt;born&lt;/em&gt;?&lt;/p&gt;&#xA;" OwnerUserId="11208" LastEditorUserId="10681" LastEditDate="2017-11-25T23:51:48.873" LastActivityDate="2019-01-09T18:53:48.383" Title="Where does the Amazon River really begin?" Tags="|hydrology|rivers|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="12425" PostTypeId="2" ParentId="12424" CreationDate="2017-10-04T00:16:24.327" Score="26" Body="&lt;p&gt;From an Earth Science standpoint, it's meaningless to ask about the &quot;source&quot; of a river in this way.  The &quot;source&quot; of a river is the rainfall within its &lt;a href=&quot;https://en.wikipedia.org/wiki/Drainage_basin&quot; rel=&quot;nofollow noreferrer&quot;&gt;drainage basin&lt;/a&gt;, which percolates down into &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Groundwater&quot; rel=&quot;nofollow noreferrer&quot;&gt;groundwater&lt;/a&gt;, and the &quot;river&quot; appears where the land has eroded down below the &lt;a href=&quot;https://en.wikipedia.org/wiki/Water_table&quot; rel=&quot;nofollow noreferrer&quot;&gt;water table&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Amazon has an enormous drainage basin: &#xA;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/0/02/Amazonriverbasin_basemap.png/600px-Amazonriverbasin_basemap.png&quot; /&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and every point in it is its &quot;source&quot; in some way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The trouble with your question is that it asks about the &quot;source&quot; of a river in a way that you first have to define what you consider the &quot;source&quot;. Does a stream begin where its name begins? Where water first permanently flows above ground? Most of the time? Some of the time? Anywhere there's a big enough pile of wet leaves?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Brazil, the part of the river above its confluence with the &lt;a href=&quot;https://en.wikipedia.org/wiki/Rio_Negro_(Amazon)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rio Negro&lt;/a&gt; at &lt;a href=&quot;https://en.wikipedia.org/wiki/Manaus&quot; rel=&quot;nofollow noreferrer&quot;&gt;Manaus&lt;/a&gt; has its own name -- the &lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Solim%C3%B5es_River&quot; rel=&quot;nofollow noreferrer&quot;&gt;Solimões&lt;/a&gt;&lt;/em&gt;, so you could say the &quot;Amazon&quot; proper begins at Manaus. But this is thousands of miles from the river's farthest upper reaches.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Wikipedia article on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Amazon_River&quot; rel=&quot;nofollow noreferrer&quot;&gt;Amazon River&lt;/a&gt; has the following to say about its &quot;farthest source&quot;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The headwaters of the Apurímac River on Nevado Mismi had been considered for nearly a century as the Amazon’s most distant source, until a 2014 study found it to be the Cordillera Rumi Cruz at the headwaters of the Mantaro River in Peru. The Mantaro and Apurímac join, and with other tributaries form the Ucayali River, which in turn meets the Marañón River upstream of Iquitos, Peru, to form what countries other than Brazil consider to be the main stem of the Amazon. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But because a tunnel associated with the Tablachaca Dam diverts water away from a big loop of the Mantaro River, effectively shortening it, all you'll ever get now is an argument about what's &quot;really&quot; the furthest source. &lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2019-01-09T18:53:48.383" LastActivityDate="2019-01-09T18:53:48.383" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="12426" PostTypeId="5" CreationDate="2017-10-04T16:26:56.327" Score="0" Body="" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2017-10-04T16:26:56.327" LastActivityDate="2017-10-04T16:26:56.327" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12427" PostTypeId="4" CreationDate="2017-10-04T16:26:56.327" Score="0" Body="Insolation is the amount of solar radiation received over a unit area of the Earth’s surface. It is affected by latitude, season, atmospheric conditions, and topography." OwnerUserId="94" LastEditorUserId="94" LastEditDate="2017-10-04T16:26:56.327" LastActivityDate="2017-10-04T16:26:56.327" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12429" PostTypeId="1" CreationDate="2017-10-05T12:17:01.540" Score="0" ViewCount="219" Body="&lt;p&gt;The archeologists use the term &lt;a href=&quot;https://books.google.com/books?id=D1HfCwAAQBAJ&amp;amp;pg=PA51&amp;amp;lpg=PA51&amp;amp;dq=%22ground-up%20shell%22&amp;amp;source=bl&amp;amp;ots=VW7Z3fNJ87&amp;amp;sig=QTWEPhWMzfrWwOpkMr6REm_4IsY&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwjW9dqmudnWAhUiD8AKHXvkBCwQ6AEISzAH#v=onepage&amp;amp;q=%22ground-up%20shell%22&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;ground-up shell&quot;&lt;/a&gt; to designate a type of temper used for pottery. What is this material? Earth containing fossilized mollusk shells? I noticed the term is also used in &lt;a href=&quot;https://books.google.com/books?id=qTliDAAAQBAJ&amp;amp;pg=PT589&amp;amp;lpg=PT589&amp;amp;dq=%22ground-up%20shell%22&amp;amp;source=bl&amp;amp;ots=72bDqFWJvD&amp;amp;sig=buq0s7jZyX8gmO4XqwUbw3D9j-c&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwjW9dqmudnWAhUiD8AKHXvkBCwQ6AEIPjAE#v=onepage&amp;amp;q=%22ground-up%20shell%22&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;texts about oysters&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11223" LastActivityDate="2017-10-05T13:43:41.117" Title="What is the definition of &quot;ground-up shell&quot;?" Tags="|rocks|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12430" PostTypeId="2" ParentId="12429" CreationDate="2017-10-05T13:43:41.117" Score="2" Body="&lt;p&gt;I'm not sure this is the best place to ask. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ground-up shell means just that - shells that have been ground (reduced to small particles or powder by crushing it). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shell tempering is one of the hallmarks of Mississippian cultural practices. It is often characterized by the adoption and use of riverine, usually mussel shells, (or more rarely marine) shell-tempering agents in the clay paste. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Read more here: &lt;a href=&quot;https://www.revolvy.com/main/index.php?s=Shell%20tempered%20pottery&amp;amp;item_type=topic&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.revolvy.com/main/index.php?s=Shell%20tempered%20pottery&amp;amp;item_type=topic&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="10710" LastActivityDate="2017-10-05T13:43:41.117" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12431" PostTypeId="1" AcceptedAnswerId="12433" CreationDate="2017-10-06T01:29:40.383" Score="10" ViewCount="1607" Body="&lt;p&gt;The line on the ground at the Greenwich Observatory is itself on a tectonic plate that is moving, so is the prime meridian still 0 degrees, 0 minutes, 0 seconds?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If not - what are the implications (if any)? For example, if my GPS says I am 100 km west of Greenwich Observatory, am I 100 km west of 0 0 0 or 100 km west of the line on the ground? Who (and what) decides this kind of thing?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Curious punter, not a scientist....&lt;/p&gt;&#xA;" OwnerUserId="11225" LastActivityDate="2019-04-22T16:25:57.863" Title="Movement of the Prime/Greenwich Meridian" Tags="|plate-tectonics|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12432" PostTypeId="2" ParentId="12431" CreationDate="2017-10-06T07:28:02.747" Score="8" Body="&lt;p&gt;Remember it is just an imaginary line on the Earth's surface used for georeferencing purposes, so movement of the reference line has no implications so long as we can still reference to it (hence the International Reference Meridian).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact, the position of the Greenwich  meridian has changed throughout history, mainly due to the Airy Transit Observatory (the original location of the Greenwich meridian) being built next door to the previous one (to maintain the service to shipping). Such changes had no significant practical effect. Historically, the average error in the determination of longitude was much larger than the change in position. The adoption of WGS84 (&quot;World Geodetic System 84&quot;) as the positioning system has moved the geodetic prime meridian 102.478 metres east of its last astronomic position (measured at Greenwich). The position of the current geodetic prime meridian is not identified at all by any kind of sign or marking (as the older astronomic position was) in Greenwich, but can be located using a GPS receiver.&#xA;Due to the movement of Earth's tectonic plates, the line of 0° longitude along the surface of the Earth has slowly moved toward the west from this shifted position by a few centimetres; that is, towards the Airy Transit Observatory  (or the Airy Transit Observatory  has moved toward the east, depending on your point of view) since 1984 (or the 1960s). With the introduction of satellite technology, it became possible to create a more accurate and detailed global map. With these advances there also arose the necessity to define a reference meridian that, whilst being derived from the Airy Transit Circle, would also take into account the effects of plate movement and variations in the way that the Earth was spinning - the International Reference Meridian.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Malys, S., Seago, J.H., Pavlis, N.K. et al.  (2015) &quot;Why the Greenwich meridian moved&quot; Journal of Geodesy. 89 (12) pp 1263–1272&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Dolan, G (2013). &quot;WGS84 and the Greenwich Meridian&quot;. The Greenwich Meridian.&lt;/p&gt;&#xA;" OwnerUserId="10710" LastActivityDate="2017-10-06T07:28:02.747" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12433" PostTypeId="2" ParentId="12431" CreationDate="2017-10-06T07:47:46.723" Score="7" Body="&lt;p&gt;This is quite a good question. There is no simple solution for it.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Prime Meridian&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Nowadays prime meridian is still in Greenwich but it was slightly moved from the original 0° 0' 0'' position (shifted by 5.34 arcseconds). It is denoted as IERS Reference Meridian (IRM). The prime Meridian should be on a plane, which splits the Earth's mass into exact halves. Due to higher resolved data on the Earth's shape and mass distribution, one realized that this was not the case for the 'original' prime Meridian. See &lt;a href=&quot;https://doi.org/10.1007/s00190-015-0844-y&quot; rel=&quot;noreferrer&quot;&gt;Malys et al. (2015) [doi: 10.1007/s00190-015-0844-y]&lt;/a&gt; for details.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Movement of Tectonic Plates&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;As you say: the continental plates move. Thus, a global perfect map from 1985 would differ from a global perfect map from 2017. If we keep our lon-lat-coordinate system constant, some real world locations move with respect to their geographical coordinates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At this point a 'reference datum' comes into play: one fixes the coordinate system on a specific date and for a specific tectonic plate. Examples are the North American Datum 1983 (NAD83) and the European Terrestrial Reference Frame 1989 (ETRF89). Thus, using NAD83, a specific building in New York did not 'move' between 1985 and 2017. With respect to ETRF89 it would have moved.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Further problems: shape of the Earth&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;We need to assume a defined shape of the Earth to map coordinates to geographic places. The simplest assumption is: the Earth is a perfect sphere. However, this is not the case. GPS coordinates are based on the World Geodetic System of 1984 (WGS84). It uses a ellipsoid is shape for the Earth and the IRM as reference meridian. The &lt;a href=&quot;https://en.wikipedia.org/wiki/World_Geodetic_System#WGS84&quot; rel=&quot;noreferrer&quot;&gt;English Wikipedia&lt;/a&gt; article is quite detailed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we assume another shape for the Earth but the same zero-meridian, most geographic locations will be projected on slightly different coordinates than they currently have. In order to maintain consistency of lon-lat-coordinates, standards like WGS84 and data like NAD83 were defined on an international level.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2017-10-06T07:47:46.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12435" PostTypeId="2" ParentId="12180" CreationDate="2017-10-07T18:53:47.180" Score="1" Body="&lt;p&gt;I am interested in the same topic. Recently, research on the determinism behind earthquake triggering has been revived based on these studies from last year:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Ide, Satoshi, Suguru Yabe, and Yoshiyuki Tanaka. &quot;Earthquake potential revealed by tidal influence on earthquake size-frequency statistics.&quot; Nature Geoscience 9.11 (2016): 834-837.&lt;/li&gt;&#xA;&lt;li&gt;van der Elst, Nicholas J., et al. &quot;Fortnightly modulation of San Andreas tremor and low-frequency earthquakes.&quot; Proceedings of the National Academy of Sciences (2016): 201524316.&lt;/li&gt;&#xA;&lt;li&gt;Delorey, Andrew A., Nicholas J. van der Elst, and Paul A. Johnson. &quot;Tidal triggering of earthquakes suggests poroelastic behavior on the San Andreas Fault.&quot; Earth and Planetary Science Letters 460 (2017): 164-170.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;A few years before these results were published, another seismologist did an extensive evaluation:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Characteristics of the earthquake-triggering pattern by Earth tides were studied utilizing over five hundred thousand events from an earthquake catalogue (NEIC-USGS) for global earthquakes with a magnitude range of 2 to 10.&quot;  -- Vinayak G. Kolvankar, &quot;Sun, Moon and Earthquakes&quot;, New Concepts in Global Tectonics Newsletter, no. 60, September, 2011.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;He was able to find correlations such as this:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/BeOIR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BeOIR.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the best bet is to look at the &lt;a href=&quot;https://earthquake.usgs.gov/data/data.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;NEIC-USGS database&lt;/a&gt;.   You should be able to cull from quite a few events across the intensity spectrum.&lt;/p&gt;&#xA;" OwnerUserId="11234" LastActivityDate="2017-10-07T18:53:47.180" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12436" PostTypeId="1" CreationDate="2017-10-07T23:28:00.773" Score="4" ViewCount="39263" Body="&lt;p&gt;Today, I was coming back from music school, and it was raining heavily. An hour after I came back, the sun started coming out from one side, and the sky wa very brighr yellow. The lighting effects that came through all my windows were spectacular.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are some images:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Athps.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Athps.jpg&quot; alt=&quot;1&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/wlDBb.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wlDBb.jpg&quot; alt=&quot;2&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/kZDbM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kZDbM.jpg&quot; alt=&quot;3&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I appreciate any explanation how phenomenon like this can occur and why.&lt;/p&gt;&#xA;" OwnerUserId="6148" LastEditorUserId="6148" LastEditDate="2017-10-07T23:43:14.557" LastActivityDate="2020-09-13T01:00:03.710" Title="Why was the sky SO yellow?" Tags="|meteorology|atmosphere|sun|light|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12437" PostTypeId="2" ParentId="12436" CreationDate="2017-10-08T04:07:51.930" Score="-1" Body="&lt;p&gt;It's a concept called rayleigh scattering. Shorter wavelengths are scattered more and longer ones are scattered less. This explains why the sky is blue. Sometimes, after a storm passes, the yellow/orange tint is a result of that reyleigh scattering.&lt;/p&gt;&#xA;" OwnerUserId="11236" LastActivityDate="2017-10-08T04:07:51.930" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12438" PostTypeId="1" CreationDate="2017-10-08T11:25:53.227" Score="5" ViewCount="3392" Body="&lt;p&gt;Let's say we invented a whizzy technology that took CO2 back to pre-industrial levels, say 280ppm, how long would it take for glaciation to resume ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(I'm not angling for a denialist perspective here, I know warming is a problem)&lt;/p&gt;&#xA;" OwnerUserId="11238" LastEditorUserId="595" LastEditDate="2017-10-09T10:02:11.493" LastActivityDate="2018-09-23T00:58:48.607" Title="When is the next glaciation due?" Tags="|climate-change|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12439" PostTypeId="2" ParentId="12436" CreationDate="2017-10-08T11:38:43.707" Score="3" Body="&lt;p&gt;In this case I'd say it's a combination of Rayleigh scattering,&lt;br&gt;&#xA;Mie scattering and the angle of the sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rayleigh scattering is related to the chemical composition of the atmosphere and occurs when the particles causing the scattering are smaller in size than the wavelengths of radiation in contact with them (this is why the sky appears blue most of the time). The yellow sky in this question is likely mostly owing to Mie scattering. Mie scattering is caused by pollen, dust, smoke, water droplets(the most likely culprit in this case), and other particles in the lower portion of the atmosphere. It occurs when the particles causing the scattering are larger than the wavelengths of radiation in contact with them. The angle of the sun and Raleigh scattering may also be at play, when the sun is low in the sky sunlight passes through more air than when the sun is higher in the sky. More atmosphere means more molecules to scatter the violet and blue light away from your eyes. If the path is long enough, all of the blue and violet light scatters out of your line of sight. The other colors continue on their way to your eyes. This is why sunsets are often yellow, orange, and red.&lt;/p&gt;&#xA;" OwnerUserId="10710" LastActivityDate="2017-10-08T11:38:43.707" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12440" PostTypeId="1" CreationDate="2017-10-08T14:54:52.000" Score="3" ViewCount="1261" Body="&lt;p&gt;I'm trying to catch up on my homework for earth science, but I'm having a difficult time searching for an answer to my question.&lt;/p&gt;&#xA;" OwnerUserId="11239" LastEditorUserId="6298" LastEditDate="2017-10-08T23:13:29.757" LastActivityDate="2019-06-26T03:02:05.197" Title="Where are the oldest igneous rocks found?" Tags="|rocks|homework|igneous|" AnswerCount="5" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12441" PostTypeId="2" ParentId="12440" CreationDate="2017-10-08T17:39:34.377" Score="6" Body="&lt;p&gt;Zircons from Australia at 4.4Ga, and perhaps basalts from a Canadian island at 4.5Ga.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It would interest you to know the quest of Boston University geochemist Matthew Jackson, who is searching for the oldest basalt and mantle rock that exists.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;His work isn't entirely agreed upon, as they are using all kinds of difficult isotopes which are a subject of controversy. Probably the most current information on early basalts are the claims and counter claims relating to Matthew Jackson in published articles, which have a lot of chemistry in them. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://news.nationalgeographic.com/news/2010/08/100812-worlds-oldest-rocks-magma-earth-nature-science/&quot; rel=&quot;noreferrer&quot;&gt;http://news.nationalgeographic.com/news/2010/08/100812-worlds-oldest-rocks-magma-earth-nature-science/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.bu.edu/today/2012/little-rock-at-center-of-big-controversy/&quot; rel=&quot;noreferrer&quot;&gt;https://www.bu.edu/today/2012/little-rock-at-center-of-big-controversy/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://scholar.google.fr/scholar?hl=en&amp;amp;as_sdt=0%2C5&amp;amp;q=tungsten+basalt++oldest&amp;amp;btnG=&quot; rel=&quot;noreferrer&quot;&gt;https://scholar.google.fr/scholar?hl=en&amp;amp;as_sdt=0%2C5&amp;amp;q=tungsten+basalt++oldest&amp;amp;btnG=&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;We've been looking for pieces of the mantle that might have survived the chaotic mixing and churning within the deep Earth,&quot; said Boston University geochemist Matthew Jackson.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;We found rocks that reached the surface some 62 million years ago—suggest a whole reservoir of the primordial rock could still lie somewhere beneath the Arctic&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are moon basalts from 3.7 Ga years ago, they are a bit mysterious, and lunar plagioclase feldspar at 4.5, appear to have formed when feldspar crystallized and floated to the top of a global magma ocean that surrounded the Moon soon after it formed.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2017-10-08T17:47:39.823" LastActivityDate="2017-10-08T17:47:39.823" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12444" PostTypeId="2" ParentId="7607" CreationDate="2017-10-09T03:37:22.757" Score="0" Body="&lt;p&gt;If you look at a catchment basin, it is nearly always bordered by mountains. it's because water flows downhill. Altitude is water's motor system. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;All the peripheries of the river system are on high points facing roughly towards the interior of the basin. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any breach in the slope will cause water to flow the other way, and because water and ice lowers the zones it passes through.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The water is very powerful and always forces it's way into a lower valley eventually and creates very large downhill paths over millions of years. The amazon basin and alps ars dozens of millions of years old. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mountains also get multiple times as much rain as valleys, and valleys are FULL of invisible underground rivulets, whereas mountains often have more over ground flow and less porous sediment. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/X55Dv.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/X55Dv.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3315" LastActivityDate="2017-10-09T03:37:22.757" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12445" PostTypeId="2" ParentId="12438" CreationDate="2017-10-09T04:18:43.330" Score="9" Body="&lt;p&gt;This answer assumes 280 PPM CO2, at least until the ice age and oceans begin to draw CO2 from the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we look at the Pleistocene and we measure how long glacial periods last and how long inter-glacial periods are, You could say, observing the Earth for the last 2.5 million years that being in an ice age is Earth's natural state, with only brief periods between ice ages.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ice ages have also followed pretty regular patterns that makes them, in theory, somewhat predictable.   Ice ages mostly followed a 40,000 year cycle, between about 2.5 million years ago to about 1 million years ago, then switched to roughly a 100,000 year cycle over the last million years.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's not precisely known why the cycle switched from 40,000 to 100,000 years.  That's known as the &lt;a href=&quot;https://en.wikipedia.org/wiki/100,000-year_problem&quot; rel=&quot;noreferrer&quot;&gt;100,000 year problem&lt;/a&gt;.  But if we use the current 100,000 year cycle as a ballpark measuring stick or if we measure the length of interglacial periods (which are generally pretty short, 10,000 - 30,000 years), then the next ice age can be estimated at not too far off.  Maybe 10,000 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But if we look closer at what actually triggers ice ages, which is (simplified version), colder summers in the Northern Hemisphere, driven by orbital variations.    We can get a better estimate when ice ages should come by looking for when the Northern Hemisphere summers will get colder.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;noreferrer&quot;&gt;Milankovich cycles&lt;/a&gt; don't always neatly line up and the right conditions for the next ice age, based on orbital changes is a bit unclear.  When the red line in this chart below is low ice ages are more likely to happen, and we're in a dip now, but coming out of a warmer summer period and relativly soon entering another one.   There's a slightly bigger dip that peaks in about 60,000 years from now, another one 100,000 years from now and a bigger one, about 130,000 years from now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7Ixma.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7Ixma.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using this chart as a guideline, the next glaciation is more tricky to predict.   Perhaps in 60,000 years.   These predictions are hard to make though because ice ages are self sustaining.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, short answer, perhaps the best answer.   Nobody knows.   The Milankovich cycles aren't lining up in the right way to make this prediction easy.  We may be set for an unusually long inter-glacial period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for how catastrophic would it be.   Well, for one, we'd see it coming and stopping an ice age would probably be easier than stopping ice from melting.  Releasing CO2 and CH4 into the air for example.  For a longer answer, how catastrophic would it be is a world-building question.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2017-10-09T04:18:43.330" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="12446" PostTypeId="2" ParentId="12418" CreationDate="2017-10-09T08:11:49.833" Score="3" Body="&lt;p&gt;From Prandle 1979&lt;a href=&quot;https://en.wikipedia.org/wiki/Maxwell&amp;#39;s_equations&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The flow of water across the vertical component of the Earth's magnetic field induces a potential gradient in the water; measurements of the difference in voltage between the opposite sides of a tidal channel provide an indication of the magnitude of the tidal flow&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I imagine that having a cable across the channel enables an accurate comparison of voltage on either side. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suspect that this is a large-scale example of the Hall Effect, but that part of my physics is too rusty to say for sure!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Maxwell&amp;#39;s_equations&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt; D. Prandle, &quot;Anomalous results for tidal flow through the Pentland Firth&quot;, Nature vol 278, pp 541-542 &lt;a href=&quot;http://www.homepages.ed.ac.uk/shs/Tidal%20Stream/Prandle%20phase%20anomaly.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.homepages.ed.ac.uk/shs/Tidal%20Stream/Prandle%20phase%20anomaly.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maxwell showed that the motion of electrically charged particles in any magnetic field creates an &lt;a href=&quot;https://en.wikipedia.org/wiki/Maxwell&amp;#39;s_equations&quot; rel=&quot;nofollow noreferrer&quot;&gt;electric field&lt;/a&gt;. The two fields would be perpendicular to one another. As seawater containing a large amount of ions (it is salty after all) moves through Earth's magnetic field in ocean currents, it generates the an electric field that as the theory predict will be perpendicular to the water current. The electric field is the result of the vertically average effect of the ocean motion. When a submarine cable is available between two points, the change in electrical current at both ends of the cable can be measured. The change will be proportional to the &quot;vertically integrated ocean current&quot; or &lt;a href=&quot;http://www-das.uwyo.edu/~geerts/cwx/notes/chap11/ocean_transport.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ocean current transport&lt;/a&gt; (the total flux of water through a given area). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first demonstrations were conducted by Henry Stommel in the 1950's. A full array of measurements are conducted in the Florida Straits taking advantage of submarine cables connecting Florida and Bahamas. The sources of errors and variability were discussed by &lt;a href=&quot;http://rsta.royalsocietypublishing.org/content/roypta/338/1650/169.full.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Larsen, 1992&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NOAA AOML provides a good description of the &lt;a href=&quot;http://www.aoml.noaa.gov/phod/floridacurrent/background.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;theory and applications&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Stommel, H., 1957. Florida Straits Transports, 1952-1956. Bulletin of Marine Science, 7(3), pp.252-254.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="39" LastEditorUserId="111" LastEditDate="2017-10-09T16:33:17.027" LastActivityDate="2017-10-09T16:33:17.027" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12449" PostTypeId="1" CreationDate="2017-10-09T14:36:55.767" Score="-2" ViewCount="118" Body="&lt;p&gt;Which parts of Antarctica are unexplored? What about the underwater world of Antarctica? Specifically, what information do we have about it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is so interesting about exploring Antarctica when everything is just a massive island of snow?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would it be worth it/beneficial/possible to place a land-exploring Rover on Antarctica which could be controlled remotely (from a warm base/away from the extreme weathers of Antarctica)? What new discoveries could be achieved?&lt;/p&gt;&#xA;" OwnerUserId="10996" LastEditorUserId="2470" LastEditDate="2021-07-06T07:05:56.693" LastActivityDate="2021-07-06T07:05:56.693" Title="Antarctica Exploration" Tags="|snow|antarctica|" AnswerCount="1" CommentCount="5" ClosedDate="2017-10-10T00:22:23.347" ContentLicense="CC BY-SA 3.0" />
  <row Id="12450" PostTypeId="2" ParentId="12449" CreationDate="2017-10-09T15:29:59.827" Score="3" Body="&lt;p&gt;What would you have an Antarctic rover do? How would you protect it from falling down a crevasse, some of which are totally obscured? What would you like to be found in Antarctica?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, Antarctica is a large snow and ice covered island. The ice being up to 4500 m thick. The analysis of Antarctic ice cores is allowing scientists to discover the composition of the Earth's atmosphere going back millions of years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are nearly 400 sub-glacial lakes in Antarctica, Lake Vostok being the largest. The lake sediments of such lakes have yielded evidence of diverse life forms going back hundreds of thousands of years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Antarctica has mountain ranges and even 138 volcanoes. Mt Erebus being the one that is best known and is still active.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Much of the exploration of Antarctica involves discovering what is beneath the ice, not so much what is on top of it.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-10-09T15:29:59.827" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12451" PostTypeId="2" ParentId="12440" CreationDate="2017-10-09T20:15:52.300" Score="-1" Body="&lt;p&gt;I remember watching a documentary years ago about diamonds and the places they are found in southern Africa. Apparently they are inclusions in the oldest rocks in that continent, which you could say fill up some sort of very large chimneys in younger rock, going vertically straight down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So there you would have at least some of the oldest rocks on the planet.&lt;/p&gt;&#xA;" OwnerUserId="11242" LastActivityDate="2017-10-09T20:15:52.300" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12452" PostTypeId="2" ParentId="10862" CreationDate="2017-10-09T21:01:51.817" Score="0" Body="&lt;p&gt;The explanation would be that the sun at that moment was deep below earth's horizon (in other words, at the place the asker was looking at the moon it would probably have been around midnight) and illuminating the moon from that point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The crescent itself shows the direction from which the sun is shining at that moment. If, keeping looking in the direction of the moon, you had lowered your gaze towards your feet, and you'd been able to see through earth, you would have seen the sun.&lt;/p&gt;&#xA;" OwnerUserId="11242" LastEditorUserId="11242" LastEditDate="2017-10-10T20:08:14.583" LastActivityDate="2017-10-10T20:08:14.583" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12453" PostTypeId="2" ParentId="7713" CreationDate="2017-10-09T22:08:40.817" Score="-1" Body="&lt;p&gt;The moon's orbit might have changed, but obviously it would take some time before this would become visible. The moon's position iself would probably not be that affected by the event as its inertia is too huge. So the tides would probably not be noticeably affected in the first hours.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have no idea really how long, but it might not take too long before, depending on what point of its new, elliptical orbit the moon is now positioned - is it now approaching earth, or more or less staying at the same distance, or to the contrary getting farther away - the tides will start to be affected.&lt;/p&gt;&#xA;" OwnerUserId="11242" LastActivityDate="2017-10-09T22:08:40.817" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12454" PostTypeId="1" AcceptedAnswerId="20034" CreationDate="2017-10-09T22:24:05.900" Score="13" ViewCount="314" Body="&lt;p&gt;I have been studying ocean currents and associated energy flows in the eastern Pacific and western Atlantic oceans.  I also looked at El Nino cycles. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also noted when the large glacial periods started 3 million years ago and noticed that these began when what is now Panama formed between North and South America by continental drift effectively separating the Gulf of Mexico from the Pacific Ocean.  The ocean currents from the Atlantic and Pacific no longer mixed from then on.  However, &lt;a href=&quot;https://www.scientificamerican.com/article/new-dating-panama-formations-cast-doubt-ice-age-origins/&quot; rel=&quot;noreferrer&quot;&gt;this article&lt;/a&gt; in Scientific American mentions some evidence that the isthmus of Panama actually formed enough to block ocean currents 10 million years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not sure on the macroscopic thermodynamics on how this contributed to the start of the Ice Ages but this is the situation.  Could be coincidental.&lt;/p&gt;&#xA;" OwnerUserId="8212" LastEditorUserId="8212" LastEditDate="2017-10-10T12:31:09.577" LastActivityDate="2020-08-06T08:49:23.637" Title="Did the formation of Panama trigger the beginning of Ice Ages?" Tags="|ocean-currents|ice-age|continent|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12456" PostTypeId="2" ParentId="12440" CreationDate="2017-10-11T07:03:53.663" Score="-1" Body="&lt;p&gt;The previous answer about the evidence of oldest crust is correct but if you are looking for the oldest igneous rocks that is a metamorphosed granitoid that formed 4.2 billion years ago. According to Wikipedia, the Acasta Gneiss is a tonalite gneiss in the Slave craton in Northwest Territories, Canada. The rock of the outcrop was metamorphosed 3.58 to 4.031 billion years ago and is the oldest known intact crustal fragment on Earth. &lt;/p&gt;&#xA;" OwnerUserId="11156" LastActivityDate="2017-10-11T07:03:53.663" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12458" PostTypeId="1" CreationDate="2017-10-11T10:16:14.233" Score="5" ViewCount="182" Body="&lt;p&gt;I want to create a variable &quot;snow cover&quot; with values presence/absence of snow for different weather stations (to work later with NDSI from Landsat images with a pixel size = 100 m). I got snow depth values (cm) from weather stations, but I'm wondering if there is a formula or a minimum depth I should consider as presence of snow. Reading the methods used to estimate snow depth, values are based on different measurements around the station, but it does not specify how big the area is. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;can you please advice on this matter?&lt;/p&gt;&#xA;" OwnerUserId="7256" LastActivityDate="2017-10-17T21:46:31.097" Title="Is there a minimum snow depth to be considered as presence of snow?" Tags="|snow|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12459" PostTypeId="1" AcceptedAnswerId="13250" CreationDate="2017-10-11T15:24:02.860" Score="5" ViewCount="5998" Body="&lt;p&gt;There was time during the age of dinosaurs when the polar regions were ice free.  The earth was obviously much warmer but a run-away greenhouse effect did not occur.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This was most likely because the continents were so configured that ocean currents more adequately transfered heat around the globe.&#xA;And&#xA;The particulate dust from volcanic activity (more active back then) accumulated in the stratosphere, reflecting solar heat and light back into space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One reason creatures of immense size such as dinosaurs were able to evolve is the oxygen requirements for the respiration and metabolism for such massive bodies were present in the atmosphere during this period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly, the fossil record indicates vegetation size was much greater during this period than today due to the higher amount of CO2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This atmosphere would have to have greater percentage composition of oxygen (for dinosaurs) and CO2 (for greenhouse affect and greater plant biomass) or a much denser atmosphere or both.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What was the density of the atmosphere back then either in terms of air pressure at today's sea level and standard temperature &#xA;Or&#xA;In kg/square meter at STP (Standard Temperature and Pressure)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What were the percentages of O2 and CO2?&lt;/p&gt;&#xA;" OwnerUserId="8212" LastEditorUserId="87" LastEditDate="2018-02-05T09:44:49.033" LastActivityDate="2019-04-03T23:23:05.053" Title="What was the density and composition of Earth's atmosphere during the Cretaceous warmest period?" Tags="|meteorology|atmosphere|paleoclimatology|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12461" PostTypeId="1" CreationDate="2017-10-12T07:08:25.017" Score="2" ViewCount="115" Body="&lt;p&gt;&lt;strong&gt;*Over some years I was hovering over the developments of the ESA SWARM mission and probing random magnetometers from the Russian-Ukrainian observatories as a private researcher and a non-scientist.&#xA;I'm trained in social sciences, so I have no background or methodology in science as a discrete discipline&#xA;Did anyone else make a connection between drifting magnetic Poles, climate change, tropical relocations and such? Did anyone explore the Sun-Earth connectivity in relation to such changes? I leave some figments of research behind. I would be more than happy if I would be provided with an informed answer, thank you *&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Impact of the Geomagnetic Field and Solar Radiation on Climate Change&lt;/p&gt;&#xA;&#xA;&lt;p&gt;V. A. Dergacheva, S. S. Vasilieva, O. M. Raspopovb, and H. Jungnerc&#xA;a Ioffe Physical–Technical Institute, Russian Academy of Sciences, St. Petersburg&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pushkov Institute of Terrestrial Magnetism, Ionosphere, and Radiowave Propagation, Russian Academy of Sciences, St. Petersburg&#xA;cUniversity of Helsinki, Finland&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Abstract—Recent studies have shown that, in addition to the role of&#xA;  solar variability, past climate changes may have been connected with&#xA;  variations in the Earth’s magnetic field elements at various&#xA;  timescales. An analysis of variations in geomagnetic field elements,&#xA;  such as field intensity, reversals, and excursions, allowed us to&#xA;  establish a link between climate changes at various timescales over&#xA;  the last millennia. Of particular interest are sharp changes in the&#xA;  geomagnetic field intensity and short reversals of the magnetic poles&#xA;  (excursions). The beginning and termination of the examined&#xA;  geomagnetic excursions can be attributed to periods of climate change.&#xA;  In this study, we analyzed the possible link between short-term&#xA;  geomagnetic variability (jerks) and climate change, as well as the&#xA;  accelerated drift of the north magnetic pole and surface temperature&#xA;  variations. The results do not rule out the possibility that&#xA;  geomagnetic field variations which modulate the cosmic ray flux could&#xA;  have played a major role in climate change in addition to previously&#xA;  induced by solar radiation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Gyre-driven decay of the Earth’s magnetic dipole&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Christopher C. Finlay1, Julien Aubert2 &amp;amp; Nicolas Gillet3&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Direct observations indicate that the magnitude of the Earth’s&#xA;  magnetic axial dipole has decreased over the past 175 years; it is now&#xA;  9% weaker than it was in 1840. Here we show how the rate of dipole&#xA;  decay may be controlled by a planetary-scale gyre in the liquid metal&#xA;  outer core. The gyre’s meridional limbs on average transport normal&#xA;  polarity magnetic flux equatorward and reverse polarity flux poleward.&#xA;  Asymmetry in the geomagnetic field, due to the South Atlantic Anomaly,&#xA;  is essential to the proposed mechanism. We find that meridional flux&#xA;  advection accounts for the majority of the dipole decay since 1840,&#xA;  especially during times of rapid decline, with magnetic diffusion&#xA;  making an almost steady contribution generally of smaller magnitude.&#xA;  Based on the morphology of the present field, and the persistent&#xA;  nature of the gyre, the current episode of dipole decay looks set to&#xA;  continue, at least for the next few decades&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Mid-Pliocene shifts in ocean overturning circulation and the onset of&#xA;  Quaternary-style climates&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sCgui.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sCgui.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;M. Sarnthein1,2,*, G. Bartoli1,3, M. Prange4, A. Schmittner5, B. Schneider1, M. Weinelt1, N. Andersen6, and&#xA;D. Garbe-Schonberg&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The precession peaks found in the 3180 record from core MD900963 are&#xA;  in excellent agreement with climatic oscillations predicted by the&#xA;  astronomical theory of climate. Our ~180 record therefore permits the&#xA;  development of an accurate astronomical time-scale. Based on our age&#xA;  model, the BrunhesMatuyama reversal is dated at 775 + 10 ka, in good&#xA;  agreement with the age estimate of 780 ka obtained by Shackleton et&#xA;  al. &lt;a href=&quot;https://i.stack.imgur.com/sCgui.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt; and recent radiochronological A r / A r datings on lavas&#xA;  [9-11].&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The astronomical theory of climate and the age of the Brunhes-Matuyama magnetic reversal&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Franck C. Bassinot, Laurent D. Labeyrie b, Edith Vincent a, Xavier Quidelleur, Nicholas J. Shackleton d, Yves Lancelot a&lt;/p&gt;&#xA;" OwnerUserId="9620" LastEditorUserId="9620" LastEditDate="2017-10-12T07:26:00.160" LastActivityDate="2017-10-12T07:26:00.160" Title="What are the arguments FOR Climate Change influenced by the drifting of Geomagnetic Poles?" Tags="|climate-change|geomagnetism|" AnswerCount="0" CommentCount="4" ClosedDate="2017-10-12T12:03:48.527" ContentLicense="CC BY-SA 3.0" />
  <row Id="12462" PostTypeId="1" AcceptedAnswerId="12476" CreationDate="2017-10-12T13:30:38.593" Score="4" ViewCount="255" Body="&lt;p&gt;The emergence of cyanobacteria caused removal of carbon dioxide from the atmosphere, resulting in Earth becoming cooler. That perhaps implies that the Earth's oceans would have boiled off (in billions of years) if life like cyanobacteria didn't evolve. Is it true?&lt;/p&gt;&#xA;" OwnerUserId="516" LastActivityDate="2017-10-13T09:57:25.753" Title="Would the oceans have boiled off if life (cyanobacteria) hadn't evolved on Earth?" Tags="|ocean|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12463" PostTypeId="1" CreationDate="2017-10-12T15:21:51.097" Score="1" ViewCount="175" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3gvO3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3gvO3.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;Found this rock during a walk along the coast and I can't tell weather the white line is a fossil or just a mark on the rock. Any help in identifing weather this is a fossil or not would be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="11262" LastEditorUserId="11263" LastEditDate="2017-10-12T15:55:42.860" LastActivityDate="2017-10-13T01:59:58.440" Title="Is this a fossil or a mark on the stone" Tags="|fossils|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12464" PostTypeId="1" AcceptedAnswerId="12482" CreationDate="2017-10-12T16:35:01.217" Score="5" ViewCount="194" Body="&lt;p&gt;A large wildfire has been burning for four days some distance from my town. The air is smoky, but not smokier than yesterday or the day before. General wisdom holds that we should all stay indoors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I enjoy my relative safety and indoor accommodations, I wonder why the indoor air is safer than the outdoor air. Even buildings that had 12-foot-wide (4-metre-wide) cargo doors open yesterday contain air less smoky than the outdoor air, or at least it smells that way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are still there fewer smoke particles per unit volume indoors? Do indoor environments trap the particles better? Why is the air safer indoors?&lt;/p&gt;&#xA;" OwnerUserId="11264" LastEditorUserId="11264" LastEditDate="2017-10-12T16:54:14.953" LastActivityDate="2021-04-15T01:24:06.380" Title="After days of smoky air, why is it healthier to stay inside?" Tags="|air-pollution|air-quality|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12466" PostTypeId="2" ParentId="12280" CreationDate="2017-10-12T21:21:51.657" Score="0" Body="&lt;p&gt;Soil loses &lt;em&gt;net&lt;/em&gt; carbon when disturbance stops carbon fixation but does not stop carbon respiration. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Carbon is fixed into organic material by photosynthesis, mostly by plants; carbon respiration is when organic material rots or is eaten, as described by communitys. Undisturbed soils have fluxes of carbon both in and out almost all the time. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most human disturbances reduce photosynthesis, so &quot;disturbed soils release carbon&quot; is an adequate shorthand. For instance, plow agriculture that keeps soil bare of plants for a significant part of the year; or moving piles of soil around for construction, or diverting streams and groundwater so that plants die of drought, or simply paving over soil. Natural disturbances can do the same. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As ecosystems mature on undisturbed soil, they tend to become more efficient at capturing energy and retaining limiting nutrients and therefore gain biomass, including soil organic material (SOM). SOM not only literally contains nutrients, but is a micro-environment that buffers nutrients, buffers water, and supports microbes that help plant roots flourish, which is why agriculture benefits from increased SOM. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even in wild environments, leaching eventually reduces the soluble nutrients and reduces total biomass (see &lt;a href=&quot;http://www.hydrology.bee.cornell.edu/BEE3710Handouts/VitousekBS75.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Vitousek &amp;amp; Reiners, 1975&lt;/a&gt;, and a lot of Vitousek's later work). The leaching takes long enough that it's also an adequate shorthand to say that undisturbed soils will accumulate soil carbon. &lt;/p&gt;&#xA;" OwnerUserId="2639" LastEditorUserId="2639" LastEditDate="2017-10-12T21:31:04.197" LastActivityDate="2017-10-12T21:31:04.197" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12467" PostTypeId="1" CreationDate="2017-10-12T21:31:49.273" Score="5" ViewCount="6102" Body="&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;What are the most common ways you would use to tell whether a given mountain glacier is advancing or retreating, judging only by its present state by looking at it? Please list anything you can think of.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Could a stream of water flowing out from under the glacier be a sign of it retreating?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="11266" LastEditorUserId="11908" LastEditDate="2018-01-31T01:06:25.933" LastActivityDate="2018-02-12T23:20:45.550" Title="Is a glacier advancing or retreating? How to tell?" Tags="|glaciology|glacier|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12468" PostTypeId="2" ParentId="12467" CreationDate="2017-10-12T21:47:41.283" Score="-1" Body="&lt;p&gt;Just my thought.  If the glacier is at least a few degrees below 32 °F (0 °C) steady state it's probably advancing.  If at 32 °F it probably melting.&lt;/p&gt;&#xA;" OwnerUserId="9548" LastEditorUserId="725" LastEditDate="2018-02-12T23:20:24.483" LastActivityDate="2018-02-12T23:20:24.483" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12469" PostTypeId="1" AcceptedAnswerId="12475" CreationDate="2017-10-12T22:53:08.217" Score="1" ViewCount="53" Body="&lt;p&gt;When a big hurricane hits, it &lt;a href=&quot;https://www.reuters.com/article/us-storm-harvey-debriscontracts/hurricane-ravaged-u-s-cities-hit-by-rising-cleanup-costs-idUSKCN1BX2M3&quot; rel=&quot;nofollow noreferrer&quot;&gt;can create debris on the scale of $\mathrm{10^8 yd^3}$&lt;/a&gt;.  Cities in Florida, Texas, and other affected areas are struggling to hire enough trucks and drivers to pick it up quickly.  But aside from that, I noticed many of the areas have started to &lt;a href=&quot;https://www.volusia.org/services/public-protection/emergency-management/pin/debris.stml&quot; rel=&quot;nofollow noreferrer&quot;&gt;burn&lt;/a&gt; the debris once it starts building up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Got to wondering... typically mulch comes in modestly pricey, and when free mulch is offered, it often goes quickly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So assuming a fair portion of debris is mulchable and is of interest to other areas, and that we can acquire typical transportation resources, then we'll set up transfer from collection sites to those other regions rather than burning it.  What would be the net pollution result?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If &lt;strong&gt;removed for mulch and such&lt;/strong&gt;: trucking pollution + decomposition (- trees saved locally??)&lt;br&gt;&#xA;If &lt;strong&gt;burned&lt;/strong&gt;: the burning pollution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously it's about approximation rather than exacts, it's probably hard to appraise the different byproducts from burning versus decomposition, and a lot probably depends upon the way it is burned.  But as a whole, can we get a rough estimate of comparable quantities/damage done... is it less pollution/damage even to truck it an average of 3000 miles?  1000 miles?  100 miles?  10 miles?  Should it be burned on the spot (if done safely)?  Would think there's got to be some way to get a very rough idea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Certainly the best option if viable might be leaving it in place to decompose.  But considering how upset people are getting at having debris around these parts a month later, exclude that option from the possibilities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Trucking or burning, how do they compare?&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-10-13T08:09:48.960" LastActivityDate="2017-10-13T11:51:42.673" Title="Less pollution: moving hurricane debris to other regions for use, or burning?" Tags="|air-pollution|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12471" PostTypeId="2" ParentId="12440" CreationDate="2017-10-13T03:38:12.473" Score="0" Body="&lt;p&gt;Just what @comprehensible said, &lt;strong&gt;zircons&lt;/strong&gt; from Jack Hills were the &lt;strong&gt;earliest materials (4.4 Ga)&lt;/strong&gt; indicating that continental-type igneous rocks are already present on Earth during this period. Note that these zircons are found within metamorphosed conglomerate beds. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, if we are talking about rocks (aggregates of material), then the &lt;strong&gt;Nuvvuagittuq greenstone belt (more or less 4.28 Ga)&lt;/strong&gt; in Canada represents the oldest known crust, which also gives us the oldest rocks on Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cheers! &lt;/p&gt;&#xA;" OwnerUserId="10947" LastActivityDate="2017-10-13T03:38:12.473" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12472" PostTypeId="2" ParentId="12221" CreationDate="2017-10-13T03:54:48.213" Score="0" Body="&lt;p&gt;In addition to previous answers, there will be some degree of partial melting at the base of the collision zone of two continental plates (Indian &amp;amp; Eurasian plates). Subsequently, this initiates deep lithospheric thickening, which has an upward component that could lift the crust. &lt;/p&gt;&#xA;" OwnerUserId="10947" LastActivityDate="2017-10-13T03:54:48.213" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12473" PostTypeId="1" AcceptedAnswerId="12474" CreationDate="2017-10-13T05:24:35.417" Score="0" ViewCount="38" Body="&lt;p&gt;I've been researching agricultural systems out of my curiosity.&#xA;And so I've been thinking how do the Officials know that the Rice Produce or &lt;strong&gt;YIELD&lt;/strong&gt;, will be &lt;strong&gt;satisfiable&lt;/strong&gt; to a certain country, or small village.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: &quot;Is there an &lt;strong&gt;existing model&lt;/strong&gt; for &lt;strong&gt;&lt;em&gt;computing Sufficiency&lt;/em&gt;&lt;/strong&gt; for a place &lt;strong&gt;based on Yield of rice&lt;/strong&gt;, and the &lt;strong&gt;Demand of the Population?&lt;/strong&gt;&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most likely I aim for a Percentage Output, but anyway I can alter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If there's none can you enlighten me of some Key terms, That can lead me into building one myself. Can be Studies, articles or Algorithms, and Approaches.&lt;/p&gt;&#xA;" OwnerUserId="11253" LastActivityDate="2017-10-13T06:56:48.927" Title="Is there an Existing Model of Computing Rice Sufficiency?" Tags="|agriculture|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12474" PostTypeId="2" ParentId="12473" CreationDate="2017-10-13T06:56:48.927" Score="1" Body="&lt;p&gt;Rice production and yield, like any other agricultural crop depends on a number of factors. These include, but not limited to:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The variety of rice being grown&lt;/li&gt;&#xA;&lt;li&gt;The fertility of the soil, and this can and does vary between regions&#xA;in countries&lt;/li&gt;&#xA;&lt;li&gt;The availability of water for the variety of rice&lt;/li&gt;&#xA;&lt;li&gt;Loss due to pests or natural events (ie weather)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;When new varieties of rice are developed, test plots are planted in various locations and the yield per area of land, typical tonnes per hectare, are ascertained. Once this has been done for a number of test plots and for a number of growing seasons, average numbers of tonnes per hectare can then be applied to larger/national plantings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Combine this with data regarding the number of people that need to be fed and the determined average of the amount of rice each person needs it is possible to determine the sufficiency of a rice production.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-10-13T06:56:48.927" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12475" PostTypeId="2" ParentId="12469" CreationDate="2017-10-13T08:02:19.080" Score="2" Body="&lt;p&gt;As the question was changed, my answer attempts to evaluate only the difference between &lt;strong&gt;burning and transporting&lt;/strong&gt;. Please correct my values if my quickly found sources are inaccurate or you find more representing. I know there is quite a few unwritten assumptions that simplify this problem.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;On average transporting via trucks emit 161.8 $\frac{CO_{2}}{short-ton-mile}$ (according to this Environmental defense fund &lt;a href=&quot;http://business.edf.org/files/2014/07/EDF-Green-Freight-Handbook.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;handbook&lt;/a&gt;). Short ton equals to 2 000 lbs.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The amount of $CO_{2}$ equivalent from burning wood is $1900 + 200 + 70 = 2170 \frac{CO_{2} eqiuv.}{kg}$ from carbon dioxide, nitrous oxide and methane respectively (according to this &lt;a href=&quot;https://www.transitionculture.org/2008/05/19/is-burning-wood-really-a-long-term-energy-descent-strategy/&quot; rel=&quot;nofollow noreferrer&quot;&gt;article&lt;/a&gt;, the link to the source of these numbers fails so please comment if these numbers aren't correct).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Now we can write an equation out of this and solve for the kilometer distance that produces equal amount of carbon dioxide equivalent.$$\frac{2170\frac{CO_{2}eq.}{kg}}{161.8\frac{CO_2}{short-ton-mile} \cdot 0.0011\frac{short-ton}{kg} \cdot 0.6213\frac{mile}{km}} \approx 20000 km$$&#xA;This is quite a large number in my opinion. I would've expected less. So quite a long distance is needed until transporting produces more $CO_2$ pollution than burning.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastEditorUserId="6465" LastEditDate="2017-10-13T11:51:42.673" LastActivityDate="2017-10-13T11:51:42.673" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12476" PostTypeId="2" ParentId="12462" CreationDate="2017-10-13T09:57:25.753" Score="3" Body="&lt;p&gt;Short answer: no. The life does contribute to the amount of CO2 in the atmosphere and the temperature on the Earth but mostly not by photosynthetic organisms. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main mechanism, which regulates the temperature and removes CO2 from the atmosphere is silicate and carbonate weathering cycle. In simple model the more CO2 you have in the atmosphere, the more acidic is rain water. More acidic rain can dissolve more of silicate and carbonate minerals and the dissolved minerals are carried to the ocean, where they either precipitate or are used by living organisms to create shells of CaCO3 (calcite) or SiO2 (opal). When these organisms die, many shells are dissolved but some shells fall all the way to the sea floor and are buried.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In simple words: more CO2 -&gt; more (acidic) rain -&gt; more weathering and C02 removal -&gt; more mineral deposits -&gt; less CO2 in the atmosphere -&gt; lower temperature -&gt; less rain &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want more information with formulas, I suggest looking up for description of carbonate–silicate geochemical cycle. &lt;/p&gt;&#xA;" OwnerUserId="11156" LastActivityDate="2017-10-13T09:57:25.753" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12477" PostTypeId="2" ParentId="4463" CreationDate="2017-10-13T10:29:30.593" Score="1" Body="&lt;p&gt;There are some suggestions in the recent paper in Nature Geoscience about Tortugal lava suite. The suite formed 89 million years ago and recorded mantle temperatures as high as Archaean komatiites. The mantle plumes are chemically and thermally heterogeneous, so the researchers interpret these rocks as the result of melting the hot core of the plume head that produced the Caribbean large igneous province. Their results imply that a mantle reservoir as hot as those responsible for some Archaean lavas has survived eons of convection in the deep Earth and is still being tapped by mantle plumes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The link: &lt;a href=&quot;https://www.nature.com/ngeo/journal/v10/n6/full/ngeo2954.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/ngeo/journal/v10/n6/full/ngeo2954.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11156" LastActivityDate="2017-10-13T10:29:30.593" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12478" PostTypeId="2" ParentId="12467" CreationDate="2017-10-13T19:47:14.280" Score="4" Body="&lt;p&gt;If, before winter snows start and temps consistently drop below sustained freezing there is less total ice mass than they prior year at the same point, it  is shrinking or in decline.  If there is more, it is growing that year. If a pattern of multiple years in the same direction, that is what the glacier is doing. Reduction of mass can be from melting or sublimation, it does not matter.  Increase can be snow, other freezing precipitation, or other water sources, again, does not mater where the ice came from, only that there is an increase.  These are simply the meaning of growing or receding.  They cannot be determined by looking, they require long term observation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Receding and advancing are actually a different concept.  They are movement of the glacier.  A glacier may be declining in size while still advancing in its path, or it may be growing, but receding, often by getting thicker at its origin.  Again, recession and advancing cannot really be detected by simple observation, it requires comparison over time and often there may be a localize short term advance while the glacier has a general average recession action.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Think of Arctic glaciers as an example.  It is generally agreed that most are in decline and shrinking in total size.  And yet, many continue to advance as can be seen by there repeated calving into the sea.  Not all, but many keep the same front edge, roughly with the sea.  A chunk breaks off, and the mass behind moves forward to replace it.  The total size though, behind that front, to the sides and the depth, the part of the glacier that feeds the advance continues to shrink though.&lt;/p&gt;&#xA;" OwnerUserId="6178" LastEditorUserId="725" LastEditDate="2018-02-12T23:20:45.550" LastActivityDate="2018-02-12T23:20:45.550" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12479" PostTypeId="1" CreationDate="2017-10-13T22:06:27.307" Score="4" ViewCount="47" Body="&lt;p&gt;I was only able to find &lt;a href=&quot;https://weather.msfc.nasa.gov/cgi-bin/sportPublishData.pl?dataset=goes16glm&amp;amp;product=group&quot; rel=&quot;nofollow noreferrer&quot;&gt;real-time data&lt;/a&gt;. Or do I have to wait until the Geostationary Lightning Mapper is greenlit for production in 2018?&lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2017-10-13T22:06:27.307" Title="Is archived lightning data from the GOES-16 beta test available?" Tags="|lightning|weather-satellites|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12481" PostTypeId="2" ParentId="12464" CreationDate="2017-10-14T07:51:55.140" Score="1" Body="&lt;p&gt;If you're in the open air you will be exposed to the full concentration of the pollutants in the air. By being inside, there's a reasonable assumption that the rate of interchange of air between inside a house and outside will be low and that inside there will be a lower concentration of pollutants.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Houses and buildings are not hermetically sealed. The gaps around windows and doors are small which results in low rate of airflow between the outside and inside of the houses and buildings. The less windy the weather the lower the flow rates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other way to consider it is when a room has been closed for a lengthy period while someone has been in the room, the air in the room becomes stuffy. This is because the air in the room is not being replaced by fresh air quickly enough to remove stuffy air. To remove to stuffy air the windows and doors need to be left open for a period of time for fresh air to replace the stuffy air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same thing happens when the air outside is heavily polluted. The air inside is cleaner and remains cleaner for a longer period if the doors and windows remain shut because the rate of transfer between air inside the building and outside is small.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-10-14T07:51:55.140" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12482" PostTypeId="2" ParentId="12464" CreationDate="2017-10-14T21:47:28.393" Score="1" Body="&lt;p&gt;If I understand your question correctly, you are asking why air inside is usually cleaner than air outside, especially if it is smokey. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Smoke is actually not a gas, but solid particles that are suspended. Because of this, the smoke particles fall down, but at a very slow rate due to resistance. When the air is blown against the wall, the smoke can either blow around the wall, or it can be deposited into the wall (think of dust build-up). Of course, smaller particles can negotiate the curve easier, so it isn't perfect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A house is (generally speaking) four walls, so if smoke was blowing against your house, even the small particles that could go around a solitary wall would be blocked off by the walls on the side of the house.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the other answers suggest, a house generally isn't perfectly cut off (hermetically sealed). This means that small openings in your house can let air and let the smallest particles of smoke in. For other reasons, that is good and bad. If too much smoke is brought in, it is hard to get out (consider a cigarette smoker inside). For example, furniture acts as a capacitor of smoke, gradually releasing it in time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In your case, consider you open your doors a bit and some smoke got inside. The smoke will diffuse throughout your house and settle into the floor. Assuming the mass of the puff of smoke is much less than the mass of air inside your house, the concentration of smoke inside your house will likely be negligible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are a number of different ways you can slow smoke down from entering into your house. Besides the ways listed above, building an anteroom may also prevent smoke from entering and make your house a bit more energy efficient. &lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-10-14T21:47:28.393" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12483" PostTypeId="1" AcceptedAnswerId="12486" CreationDate="2017-10-15T02:14:29.160" Score="1" ViewCount="674" Body="&lt;p&gt;Rock found along northern Lake Michigan, (Charlevoix, MI).  Made up of very thin crystalline layers. There are small, round bubble like bumps that protrude from the surface. Doesn't show well in the picture, but the rock has a sugary appearance.&lt;a href=&quot;https://i.stack.imgur.com/xNgwH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xNgwH.jpg&quot; alt=&quot;top view[![][1]&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/fMP5w.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fMP5w.jpg&quot; alt=&quot;cross section&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="11274" LastActivityDate="2019-07-08T11:55:41.467" Title="What is this Lake Michigan rock?" Tags="|geology|rocks|mineralogy|" AnswerCount="4" CommentCount="0" ClosedDate="2019-08-29T19:44:47.060" ContentLicense="CC BY-SA 3.0" />
  <row Id="12485" PostTypeId="2" ParentId="12458" CreationDate="2017-10-15T20:23:35.903" Score="0" Body="&lt;p&gt;Not an expert here - but my thought is that you have to assume that the snow cover is reasonably even around the weather stations, because you have no way of doing otherwise - so my advice would be to &quot;calibrate&quot; by comparing against the Landsat images at the locations of the weather stations, and determine what amount of snow cover generally corresponds to the pixel appearing snowed.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2017-10-15T20:23:35.903" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12486" PostTypeId="2" ParentId="12483" CreationDate="2017-10-16T17:14:24.817" Score="5" Body="&lt;p&gt;I can't be definite but my three best guesses are Travertine, Agate and maybe Halite, if it fizzes in mild acid it's Travertine, a form of Limestone, if it dissolves in hot water it's Halite, or Rocksalt, otherwise if it's more or less inert it's probably Agate, an amorphous silicate. I find Halite unlikely, the other two are probably pretty equally likely in that location.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2017-10-16T17:14:24.817" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12487" PostTypeId="2" ParentId="12467" CreationDate="2017-10-16T17:39:12.700" Score="6" Body="&lt;p&gt;The only signs I know of to identify glacial retreat on first meeting is the presence or absence of &quot;dead ice&quot;, the presence of &quot;push&quot; on moraines, and the state of any terminal lake. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Dead-ice&quot; rel=&quot;noreferrer&quot;&gt;Dead-ice&lt;/a&gt; is a term used to refer to lumps of ice left behind by a retreating glacier, they're generally cloaked in thick layers of debris that insulate them from solar heating, they don't necessarily show a current state of retreat as they can persist for many years after the glacier abandons them.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Moraine Push is a sign of current advancement or surge of the glacier, basically the glacier bulldozers existing &lt;a href=&quot;https://en.wikipedia.org/wiki/Moraine&quot; rel=&quot;noreferrer&quot;&gt;moraine deposits&lt;/a&gt; as it advances down valley, this creates several telltale formations, ice flowing over the top of lateral moraines, established moraines (trees and all) being churned and pushed over by advancing ice.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;I have heard that terminal lakes are only &lt;em&gt;ever&lt;/em&gt; found in glacial valleys with retreating ice, as they form between the face or toe of the glacier and the terminal moraine formed by a stable glacier this could well be accurate.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;These are identifiers that &lt;em&gt;can&lt;/em&gt; indicate advance or retreat, either current or historic, but at a glance there are no definitive signs of any long-term trend in the glaciers' behaviour. This is chiefly because glaciers advance and retreat on a seasonal basis so a particular feature may be the product of one winter of heavy snow (some years ago) or one very hot summer.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2017-10-16T17:39:12.700" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12488" PostTypeId="1" CreationDate="2017-10-17T10:17:40.350" Score="1" ViewCount="360" Body="&lt;p&gt;What websites are there providing visual weather data? The question actually contains the past and future weather. The purpose is for this question is to provide a list of easy-to-access websites that give a weather enthusiast/researcher overview of the weather at a given time. Please list what models the website uses and other describing information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ps. I think this should be a community wiki question and answer so that the list can be updated. So feel free to edit this question too.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastEditorUserId="6465" LastEditDate="2017-10-17T10:27:54.750" LastActivityDate="2017-10-17T15:45:54.800" Title="Websites providing visual weather data" Tags="|meteorology|atmosphere-modelling|weather-forecasting|visualization|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12489" PostTypeId="2" ParentId="12488" CreationDate="2017-10-17T10:27:36.043" Score="1" Body="&lt;p&gt;&lt;strong&gt;&lt;a href=&quot;http://www.ventusky.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;VentuSky&lt;/a&gt;&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Uses ICON, GFS, GEM (global) and HRRR (US) models with respective forecast times 4, 9, 9 and 2 days respectively. Map can be played as animation. Animation and weather map settings can be changed by the user. Map is zoom-able. Has nice customizable wind animation. Is made by a Czech Republic company called InMeteo.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Please add more to this community post. Also previous posts can be edited f.e. if some attribute is in all websites it is probably unnecessary to mention.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastEditorUserId="6465" LastEditDate="2017-10-17T10:34:41.187" LastActivityDate="2017-10-17T10:34:41.187" CommentCount="0" CommunityOwnedDate="2017-10-17T10:27:36.043" ContentLicense="CC BY-SA 3.0" />
  <row Id="12490" PostTypeId="2" ParentId="12488" CreationDate="2017-10-17T10:59:36.013" Score="3" Body="&lt;p&gt;&lt;strong&gt;&lt;a href=&quot;https://weather.us/model-charts/euro&quot; rel=&quot;nofollow noreferrer&quot;&gt;weather.us&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;If somebody is looking for free global ECMWF forecasts the above site provides a fairly complete set of links that provide information 10 days into the future. You can track the control member(which I believe is a deterministic forecast) and also the ensemble output.  In addition you can look at worldwide lightning detection sites as well as radar images of US and other selected countries. For followers of tropical meteorology  hurricane tracks of ECMWF are also available - &lt;a href=&quot;https://weather.us/cyclone-tracks&quot; rel=&quot;nofollow noreferrer&quot;&gt;ECMWF  cyclone tracks&lt;/a&gt;. &#xA;The availability of free ECMWF forecasts comes via the courtesy of Jörg Kachelmann who owns the site.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerDisplayName="user1066" LastEditorUserId="6465" LastEditDate="2017-10-17T12:29:14.710" LastActivityDate="2017-10-17T12:29:14.710" CommentCount="5" CommunityOwnedDate="2017-10-17T11:05:15.563" ContentLicense="CC BY-SA 3.0" />
  <row Id="12491" PostTypeId="2" ParentId="12488" CreationDate="2017-10-17T15:39:52.847" Score="3" Body="&lt;p&gt;For forecasting, there is a ton of data on the internet. Here are just a few sources.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A Penn State professor compiled a list of weather websites on a webpage&#xA;called &lt;a href=&quot;http://www.meteo.psu.edu/~j2n/natlwx.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Weather Connections&lt;/a&gt;. I'd explore that.&lt;/li&gt;&#xA;&lt;li&gt;The &lt;a href=&quot;http://mp1.met.psu.edu/~fxg1/ewall.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Penn State E-wall&lt;/a&gt; is commonly used, primarily for forecasts.&#xA;The NARR tab has visual data all the way back to 1979, while the&#xA;primary page has operational model data.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.twisterdata.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Twister data&lt;/a&gt; primarily has forecast data, but also has a nice&#xA;feature to plot Skew-Ts.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://wwwl.accuweather.com/pro_login.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Accuweather Pro&lt;/a&gt; probably is one of the most complete forecasting&#xA;websites around. The downside is that you have to pay a subscription.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.tropicaltidbits.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tropical tidbits&lt;/a&gt; is a useful forecasting website too.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://training.weather.gov/wdtd/tools/BUFKIT/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;BUFKIT&lt;/a&gt; with pages providing the data, is a well established&#xA;tool.&lt;/li&gt;&#xA;&lt;li&gt;NCEP also has an &lt;a href=&quot;http://www.spc.noaa.gov/exper/sref/srefplumes/&quot; rel=&quot;nofollow noreferrer&quot;&gt;SREF Plume viewer&lt;/a&gt; and a &lt;a href=&quot;http://www.emc.ncep.noaa.gov/mmb/cguastini/gefs/EMCGEFSplumes.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;GEFS plume viewer&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, there aren't too many places with archived data is a visually appealing manor. One reason for that is that there is enough data for just forecasting, that it is hard to keep up with it.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;University of Wyoming has a &lt;a href=&quot;http://weather.uwyo.edu/upperair/sounding.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;soundings archive&lt;/a&gt; that is useful.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.ncdc.noaa.gov/nexradinv/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Downloadable archived Radar data&lt;/a&gt; is able to be viewed using the&#xA;&lt;a href=&quot;https://www.ncdc.noaa.gov/wct/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weather and climate toolkit&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Though I haven't used it extensively, I did find an &lt;a href=&quot;https://gis.ncdc.noaa.gov/maps/ncei/radar&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCDC GIS product&#xA;with radar data&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;The NOHRSC has an interactive satellite-derived &lt;a href=&quot;https://www.nohrsc.noaa.gov/interactive/html/map.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;map to show snow&#xA;depth&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;While it isn't exactly perfect, the &lt;a href=&quot;https://archive.org/web/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wayback machine&lt;/a&gt;&#xA;intermittently archives images of websites. Sometimes it works.&#xA;Sometimes it doesn't.&lt;/li&gt;&#xA;&lt;li&gt;The &lt;a href=&quot;http://www.wpc.ncep.noaa.gov/archives/web_pages/sfc/sfc_archive.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;WPC weather map archive&lt;/a&gt; can also give a synoptic flavor to&#xA;previous weather.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www2.mmm.ucar.edu/imagearchive/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This NCAR image archive sometimes works.&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;There are many, many more websites. Yet, the best products are ones you design yourself.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2017-10-17T15:45:54.800" LastActivityDate="2017-10-17T15:45:54.800" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12492" PostTypeId="2" ParentId="11950" CreationDate="2017-10-17T17:02:05.207" Score="3" Body="&lt;p&gt;The assumption that the earth's reflectivity is random (i.e. has a white spectrum) is only necessary for the statistical extraction of a wavelet from the data itself via the amplitude spectrum of the autocorrelation function. The convolutional model still works regardless of the reflectivity pattern, although getting a wavelet may be more difficult if the &quot;white reflectivity&quot; assumption does not hold.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, in most sedimentary basins, earth's reflectivity pattern tends to not be random. Sedimentary deposition happens in nested cycles forming smaller cyclic layers within large cycle layers. This fractal nature is observed in the amplitude spectrum of real (i.e. measured) reflectivity series. Instead of a having a flat (i.e. white) amplitude spectrum, real reflectivity series tend to have low amplitudes in the lower frequencies and high amplitudes in the high frequencies (i.e. blue) while generally conforming to a consistent positive slope line when ploted in octave vs dB. The slope of this line is a characteristic of the local geology and contains information about the fractal nature of the layering.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This concept is used in a technique called spectral blueing (and also similarily in coloured inversion), where seismic data is forced to match the characteristic reflectivity amplitude spectrum line causing an increase in apparent bandwidth.&lt;/p&gt;&#xA;" OwnerUserId="4636" LastActivityDate="2017-10-17T17:02:05.207" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12493" PostTypeId="2" ParentId="10884" CreationDate="2017-10-17T17:16:14.217" Score="1" Body="&lt;p&gt;You can think of this amplitude term as being part of the wavelet term such that your definition of the wavelet is: &quot;the necessary filter/operator to convert true reflectivity into the arbitrarily scaled seismic data&quot;. This scalar depends on the data itself and therefore must be obtained empirically. In fact, it is very likely that the scalar is frequency dependent. Your best bet to obtain the full wavelet, including its scalar, is by using a well where your reflectivity is known and applying the method of &lt;a href=&quot;https://www.crewes.org/ForOurSponsors/ResearchReports/2014/CRR201418.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;White and Simm (2003) or any other similar method&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyway, doing any sort of deconvolution or inversion with the wrong wavelet scalar will leak all error from this into the solution. You are pretty much asking: &quot;What is the necessary (for example) acoustic impedance such that when I do this faulty forward modeling, I get the measured seismic data?&quot;.&lt;/p&gt;&#xA;" OwnerUserId="4636" LastEditorUserId="4636" LastEditDate="2017-10-18T05:21:53.217" LastActivityDate="2017-10-18T05:21:53.217" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12494" PostTypeId="2" ParentId="12458" CreationDate="2017-10-17T21:46:31.097" Score="4" Body="&lt;p&gt;A measureable amount of precipitation is considered to be at least 0.01 inch of water. Since on the average 10 inches of snow melt to 1 inch of water, this corresponds on the average to 0.1 inch of snow. Anything less is considered a trace (too little to measure).&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-10-17T21:46:31.097" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12495" PostTypeId="2" ParentId="7617" CreationDate="2017-10-18T01:22:02.073" Score="11" Body="&lt;p&gt;The clouds in which snow originates must of course be below the freezing point 0°C = 32°F.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Two factors allow snow to reach the surface when the near-ground air temperature is above freezing.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The time delay --- snowflakes may not have time to melt before reaching the surface if the surface temperature is not much above freezing. Strong downdraft air motion and larger snowflakes helps at this, bringing snowflakes down faster.&lt;/li&gt;&#xA;&lt;li&gt;Once snowflakes fall below the clouds, they are in air at&#xA;less than 100% relative humidity. &lt;a href=&quot;https://en.wikipedia.org/wiki/Deposition_(phase_transition)&quot; rel=&quot;noreferrer&quot;&gt;Sublimation&lt;/a&gt; --- evaporation&#xA;from solid to vapor --- of some snow on the outer edges of a&#xA;snowflake can then occur. This removes energy from the snowflake&#xA;overall, so it can help keep the rest of the snowflake a few degrees&#xA;cooler than the surrounding air.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The highest near-surface (at the official 5 foot height of instrument shelters) air temperature at which I have ever read of snowflakes reaching the ground is 10°C = 50°F.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastEditorUserId="8382" LastEditDate="2017-10-18T22:04:12.877" LastActivityDate="2017-10-18T22:04:12.877" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12496" PostTypeId="2" ParentId="9280" CreationDate="2017-10-18T12:13:13.080" Score="2" Body="&lt;p&gt;It looks like onion skin weathering. It appears in places with large temperature differences between night and day and associated thermal expansion and contraction of rocks on daily basis. That creates weaker spherical zones, where cracks may form later. I have seen that several times in basalts but not limestones, though. &lt;/p&gt;&#xA;" OwnerUserId="11156" LastActivityDate="2017-10-18T12:13:13.080" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12497" PostTypeId="1" AcceptedAnswerId="12498" CreationDate="2017-10-18T14:28:10.867" Score="9" ViewCount="1099" Body="&lt;p&gt;Detection of a new 50 km long lava tube in the Moon has just been reported. See &lt;a href=&quot;http://www.asahi.com/ajw/articles/AJ201710180045.html&quot; rel=&quot;noreferrer&quot;&gt;JAXA probe finds 50-km cavern under surface of the moon&lt;/a&gt;, this &lt;a href=&quot;http://www.isas.jaxa.jp/topics/001156.html&quot; rel=&quot;noreferrer&quot;&gt;JAXA news page&lt;/a&gt; (the English page has not yet been updated, stay tuned) and &lt;a href=&quot;http://onlinelibrary.wiley.com/wol1/doi/10.1002/2017GL074998/abstract&quot; rel=&quot;noreferrer&quot;&gt;Detection of intact lava tubes at Marius Hills on the Moon by SELENE (Kaguya) Lunar Radar Sounder&lt;/a&gt; Kaku, T. et al, accepted for publication in Geophysical Research Letters, DOI: 10.1002/2017GL074998.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The discovery of the sub-surface tube is a result of careful analysis of low frequency radar soundings from about eight years ago, as described in &lt;a href=&quot;https://space.stackexchange.com/a/23436/12102&quot;&gt;this answer&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AUjbV.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AUjbV.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is also a previously reported, partially collapsed lava tube, visible from surface imagery, shown below, which also seems to be about 50 km long.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; This seems extremely long to me. I'm not very familliar with this field, but isn't it unusual for a well defined, narrow flow to continue for such a long distance? Is there anything of similar length on Earth?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; Previously identified collapsed cave from &lt;a href=&quot;https://www.nasa.gov/mission_pages/LRO/multimedia/lroimages/lroc-20110217-chain.html&quot; rel=&quot;noreferrer&quot;&gt;Lunar Reconnaissance Orbiter imagery&lt;/a&gt;, captioned:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This section of WAC frame M117773324 shows the area where the feature transitions from a chain of collapse pits to a continuous uncollapsed segment. A large depression at the northern tip of the chain maybe a possible source region for the flow of lava across this region. The chain is approximately 50 km long. Image resolution 58.9 m/pixel [NASA/GSFC/Arizona State University]. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0UK92.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0UK92.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2017-10-18T16:11:49.997" Title="What conditions could produce 50 km long lava tubes?" Tags="|volcanology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12498" PostTypeId="2" ParentId="12497" CreationDate="2017-10-18T16:04:06.387" Score="11" Body="&lt;p&gt;In Hawaii, the &lt;a href=&quot;http://twistedsifter.com/2012/08/pictures-of-lava-tubes-around-the-world/&quot; rel=&quot;noreferrer&quot;&gt;Mauna Loa lava tube from the 1859 lava flow&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;enters the ocean about 50 kilometers (31 mi) from its eruption point&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Undara_Volcanic_National_Park&quot; rel=&quot;noreferrer&quot;&gt;Undara Volcanic National Park&lt;/a&gt; in Queensland, Australia&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Bayliss Cave is the remains of a lava tube that was once over 100 kilometres (62 mi) in length.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So a lava tube, 50 km long on the Moon, may not be that remarkable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, The Undara field has feature call &lt;a href=&quot;http://volcano.oregonstate.edu/undara&quot; rel=&quot;noreferrer&quot;&gt;the Wall&lt;/a&gt;, which is a continuous ridge 40 km long and 20 m high. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Wall is believed to be the closest terrestrial analogue to the basaltic ridges seen on the moon. The longest lava flows in the Solar System are on Venus. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2017-10-18T16:11:49.997" LastActivityDate="2017-10-18T16:11:49.997" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12500" PostTypeId="1" AcceptedAnswerId="12547" CreationDate="2017-10-19T05:29:47.747" Score="8" ViewCount="2550" Body="&lt;p&gt;First off, I am a biologist, not an earth scientist. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Very recently I heard about a very interesting biological phenomenon that has its origins rooted in geology : The Wallace Line. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From a biological perspective, this is very interesting. Wikipedia explains it very, but in short: The Wallace Line describes that in south east Asia there is a very strong divide in occurrence of species when comparing everything from Bali westward, and everything from Lombok eastward. e.g. large mammals characterizing Sumatra and Java are: Tigers, Elephants and Rhinos. Whereas eastward of the Wallace Line, you have your Marsupials. The same goes for many other different animal and plant species. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Explanation given is that many many many years ago when the sea level was much lower, there was an oceanic divide between east and west of south east Asia. This is supposed to be the result of tectonic movement. However, I have not been able to find a detailed explanation what could have caused this deeper oceanic divide. If I look at maps of tectonic plates and tectonic activity in the region, there are no tectonic boundaries that overlap the Wallace line. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So all this leading to my question: What could have been the cause of the this deep divide? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://darwinlive.com/wallace/images/wallaceline.jpg&quot; rel=&quot;noreferrer&quot;&gt;Here a link of the Wallace Line&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://atlantisjavasea.files.wordpress.com/2015/09/sundaland-last-glacial-maximum_75.png&quot; rel=&quot;noreferrer&quot;&gt;Here a link of Indonesian Bathymetry&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="11296" LastActivityDate="2021-09-23T03:15:27.353" Title="Cause of Wallace line" Tags="|geology|plate-tectonics|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12501" PostTypeId="1" CreationDate="2017-10-19T12:29:46.250" Score="4" ViewCount="83" Body="&lt;p&gt;Has the process of formation of sand roses been simulated in laboratory conditions, or does it take too long?&lt;/p&gt;&#xA;" OwnerUserId="10751" LastEditorUserId="10751" LastEditDate="2017-10-19T21:03:38.280" LastActivityDate="2017-10-22T07:16:52.400" Title="Can the formation of gypsum evaporites (sand roses) be simulated in the lab?" Tags="|desert|crystals|evaporation|laboratory|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12502" PostTypeId="1" AcceptedAnswerId="14460" CreationDate="2017-10-19T12:38:09.960" Score="3" ViewCount="249" Body="&lt;p&gt;How much sample of volcanic rock is required to undertake a K-Ar date measurement, and does it matter if the rock contains vesicles? Are there tricks of the trade to get a good sample?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2023-12-06T18:10:31.133" Title="How to sample for K-Ar dating?" Tags="|dating|age|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12504" PostTypeId="1" CreationDate="2017-10-20T00:36:18.330" Score="4" ViewCount="21845" Body="&lt;p&gt;What are there any loneliest places on earth in term of population per time-zone? What is the answer for full hour time-zones (UTC+1,UTC+2..) &lt;strong&gt;and&lt;/strong&gt; in other including for example UTC+4:30?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;SORRY&#xA;I may have actually meant, what is the loneliest time? When is the least amount of people awake (perhaps even including rare cycles; eclipses, solar minimums, etc)? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, meaning that if you lived in the right place, at the right time, you would be one of the loneliest men on Earth.&lt;/p&gt;&#xA;" OwnerUserId="11301" LastEditorUserId="20" LastEditDate="2017-10-21T23:48:19.117" LastActivityDate="2021-07-09T12:08:18.403" Title="Least populated time-zones" Tags="|geography|time|" AnswerCount="2" CommentCount="2" ClosedDate="2017-10-21T22:13:04.400" ContentLicense="CC BY-SA 3.0" />
  <row Id="12507" PostTypeId="2" ParentId="12504" CreationDate="2017-10-20T06:08:13.130" Score="1" Body="&lt;p&gt;Communisty has done a good job of giving the winners in various categories, but I think it's also worth mentioning the runner-up &lt;a href=&quot;https://en.wikipedia.org/wiki/UTC%2B12:45&quot; rel=&quot;nofollow noreferrer&quot;&gt;UTC+12:45&lt;/a&gt;, which is only used by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Chatham_Islands#Chathams_time&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chatham Islands&lt;/a&gt;, population 600. But UTC-12:00 beats this one, unless there happen to be enough ships in UTC-12:00 to furnish more than 600 people. And UTC+10:30 with 382 people seems indisputably lonelier.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/UTC%2B08:45&quot; rel=&quot;nofollow noreferrer&quot;&gt;UTC+08:45&lt;/a&gt;, mentioned by Tbb in the comments, is another candidate, but as the Wikipedia article says it's not officially recognized.&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2017-10-22T08:36:34.747" LastActivityDate="2017-10-22T08:36:34.747" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12508" PostTypeId="2" ParentId="12504" CreationDate="2017-10-20T07:31:41.473" Score="10" Body="&lt;p&gt;There is one timezone that is &lt;strong&gt;completely uninhabited&lt;/strong&gt;: the &lt;a href=&quot;https://en.wikipedia.org/wiki/UTC%E2%88%9212:00&quot; rel=&quot;nofollow noreferrer&quot;&gt;UTC-12:00&lt;/a&gt;. It covers only two islands: Baker Island and Howland Island that are both uninhabited (owned by US). Because of the weird way timezones are divided in the pacific there are timezones that practically use the same time (e.g. UTC+12 and UTC-12), but are actually in two different days. However if you strictly interpret the question no-one is lonely here as there is no-one here, so this might not comply.&lt;/p&gt;&#xA;&lt;p&gt;The second least population is at &lt;a href=&quot;https://en.wikipedia.org/wiki/UTC%2B08:45&quot; rel=&quot;nofollow noreferrer&quot;&gt;UTC+08:45&lt;/a&gt; that covers village of Eucla and other villages in Australia with a population of around 200. The area is surrounded by signs to remind you to turn your clocks, but it is unofficial so it might not comply either.&lt;/p&gt;&#xA;&lt;p&gt;The third least population is at &lt;a href=&quot;https://en.wikipedia.org/wiki/Lord_Howe_Island&quot; rel=&quot;nofollow noreferrer&quot;&gt;UTC+10:30&lt;/a&gt; that covers an island called the Lord Howe Island that belongs to Australia and is inhabited by 382 people. If you don't accept timezones that aren't in integer changes from UTC then this UTC+10:30 might not satisfy your curiosity.&lt;/p&gt;&#xA;&lt;p&gt;The first full integer timezone shift from UTC (that has any population) is &lt;a href=&quot;https://en.wikipedia.org/wiki/UTC%E2%88%9202:00&quot; rel=&quot;nofollow noreferrer&quot;&gt;UTC-02:00&lt;/a&gt; that consists of Atlantic islands of Brazil like Fernando de Noronha, Trindade, Martim Vaz etc. Also South Georgia and South Sandwich Islands of UK belong in this timezone. The total population then is somewhere around 2700 people. Unfortunately these are the places that use this timezone all year round and other areas like densely populated Brazilian cities use this timezone as daylight saving during their summer increasing the population drastically so even this timezone might not satisfy your criteria.&lt;/p&gt;&#xA;&lt;p&gt;Finally &lt;a href=&quot;https://en.wikipedia.org/wiki/UTC%E2%88%9211:00&quot; rel=&quot;nofollow noreferrer&quot;&gt;UTC-11:00&lt;/a&gt; being full integer change from UTC, with only all year round usage (isn't a daylight saving timezone for anyplace) consists of American Samoa, Midway Atoll, Jarvis Island and Palmyra Atoll of US and Niue of New Zealand and has under 60000 inhabitants.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Ps&lt;/strong&gt;. The estimated population numbers are from the wikipedia pages of the locations mentioned.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastEditorUserId="22964" LastEditDate="2021-07-09T12:08:18.403" LastActivityDate="2021-07-09T12:08:18.403" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="12512" PostTypeId="1" CreationDate="2017-10-20T13:48:59.110" Score="3" ViewCount="2037" Body="&lt;p&gt;I have created a x,y netcdf file and now want to add additional time energy variable. So that for each grid cell I have a energy time value.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My script is like this in Python:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;value = loadtxt(&quot;countries.txt&quot;,skiprows=0) % countries&#xA;data = loadtxt(&quot;energy.txt&quot;,skiprows=0) % energy&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The &lt;code&gt;energy.txt&lt;/code&gt; file is like:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;[country id]    ...   51      52      54      55      56      59       60      62    ...  &#xA;[time step 1]   ...  nan     649     nan     nan    1083    9979      nan   13602    ...&#xA;[time step 2]   ... 5743    1283    9062    4026     nan    6365    43444     nan    ...&#xA;[time step n]   ...  ...     ...     ...     ...     ...     ...      ...     ...    ...&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;etc (till 87648 steps), where cells of interest are the first row:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;code&gt;cellsOfInt=data[0,:]&lt;/code&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;For some cells I have nan values since there are not values for those time steps. &lt;/li&gt;&#xA;&lt;li&gt;Each row correspond to one time step so for cell of interest 51, &#xA;in the first time step we have nan value, in the second time step we have 5743 and so on till 87648.&lt;/li&gt;&#xA;&lt;li&gt;All cells of interest are in countries.txt file that is 950 X 1000 with cells of interest ids or nan when there is no value. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;My code:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;y = nc.createDimension(&quot;y&quot;, 950)  #y&#xA;x = nc.createDimension(&quot;x&quot;, 1000) #x&#xA;time = nc.createDimension(&quot;time&quot;, 87648) #time&#xA;&#xA;latitude=nc.createVariable(&quot;y&quot;, &quot;f8&quot;, (&quot;y&quot;, ))&#xA;longitude=nc.createVariable(&quot;x&quot;, &quot;f8&quot;, (&quot;x&quot;, ))&#xA;time = nc.createVariable(&quot;time&quot;,&quot;f8&quot;,(&quot;time&quot;,))&#xA;countries = nc.createVariable(&quot;countries&quot;, &quot;f8&quot;, (&quot;y&quot;, &quot;x&quot;));&#xA;energy = nc.createVariable(&quot;energy&quot;, &quot;f8&quot;, (&quot;time&quot;, &quot;y&quot;, &quot;x&quot;), &#xA;                           fill_value=-9999, chunksizes=(1, 950, 1000));&#xA;&#xA;time.standard_name='time'&#xA;time.units ='hours since 2006-01-01 00:00:00.0'&#xA;time.calendar='proleptic_gregorian'&#xA;&#xA;lats =  np.arange(5497500,747500,-5000)    #y  &#xA;lons =  np.arange(2502500,7502500,5000)    #x &#xA;&#xA;# Fill variables&#xA;latitude[:] = lats&#xA;longitude[:] = lons&#xA;&#xA;countries [:]=value&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;UNTIL HERE WORKS FINE I have my 2d country but then it does not give any result for energy:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;for i in xrange(0,950):  #rows&#xA;    for j in xrange(0,1000):    #columns&#xA;        for n in xrange(0,87648):  #rows&#xA;            for m in xrange(0,1):    #columns&#xA;                if data[1,m] == countries[i,j]:   #correspondance&#xA;                    nc.variables[&quot;energy&quot;][n]=data[n,m]&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Any idea how to fix this so I can have in country.netcdf file time dimension with energy values at each time step? Thanks a lot!!&lt;/p&gt;&#xA;" OwnerUserId="11304" LastEditorUserId="5594" LastEditDate="2017-10-22T08:45:43.503" LastActivityDate="2017-11-22T16:33:12.617" Title="Adding time dimension and corresponding new variable to a netcdf file" Tags="|netcdf|time|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12513" PostTypeId="1" CreationDate="2017-10-20T21:05:44.163" Score="3" ViewCount="626" Body="&lt;p&gt;In my Environmental Science class, we were given this data with the sample # and abundance given. I would have to solve for relative abundance, which is finished below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\begin{array}{c|lcr}&#xA;Taxa &amp;amp; \text{Sample #} &amp;amp; \text{Abundance} &amp;amp; \text{Relative Abundance} \\&#xA;\hline&#xA;A &amp;amp; 1 &amp;amp; 100 &amp;amp; 0.71 \\&#xA;B &amp;amp; 2 &amp;amp; 20 &amp;amp; 0.14 \\&#xA;C &amp;amp; 5 &amp;amp; 5 &amp;amp; 0.04 \\&#xA;D &amp;amp; 59 &amp;amp; 8 &amp;amp; 0.06 \\&#xA;E &amp;amp; 150 &amp;amp; 2 &amp;amp; 0.01 \\&#xA;F &amp;amp; 223 &amp;amp; 1 &amp;amp; 0.01 \\&#xA;G &amp;amp; 257 &amp;amp; 2 &amp;amp; 0.01 \\&#xA;H &amp;amp; 400 &amp;amp; 2 &amp;amp; 0.01 \\&#xA;\end{array}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sum of the abundance is 140, which was used to find the relative abundance. With this data, I know how to make a rank abundance curve, but I do not understand how to make a species accumulation curve. This is the finished species accumulation curve shown in class:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VH64b.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VH64b.gif&quot; alt=&quot;species accumulation curve&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do not understand this graph and I would like some help in interpreting it because I would need to be able to make a species accumulation curve of my own by hand. Preferably, I would like some help in how to plot it with the data I was given. Thank you!&lt;/p&gt;&#xA;" OwnerUserId="11305" LastEditorUserId="11305" LastEditDate="2017-10-22T18:50:47.487" LastActivityDate="2017-10-22T18:50:47.487" Title="How to create a species accumulation curve by hand?" Tags="|environmental-protection|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12517" PostTypeId="2" ParentId="12501" CreationDate="2017-10-22T07:16:52.400" Score="2" Body="&lt;p&gt;Yes, it has.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cody &amp;amp; Cody (1998), Journal of Sedimentary Research.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://archives.datapages.com/data/sepm/journals/v55-58/data/058/058002/0247.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://archives.datapages.com/data/sepm/journals/v55-58/data/058/058002/0247.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Abstract:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Gypsum crystals were grown in experimental conditions analogous to&#xA;  saline terrestrial environments within bentonite clay gels by&#xA;  diffusion control at three different temperatures, four brine&#xA;  salinities, and four tannic acid (a model terrestrial humic substance)&#xA;  concentrations. The resulting crystals correspond to natural gypsum&#xA;  formed in terrestrial environments. Prismatic gypsum typically grew at&#xA;  both high and low temperatures in the absence of the organic additive.&#xA;  With increasing organic acid concentrations, the prismatic crystals&#xA;  progressively became flattened perpendicular to [001], and two&#xA;  temperature-dependent trends developed. At low temperatures, a&#xA;  hemi-bipyramidal habit dominated by 1111 faces developed, whereas the&#xA;  lenticular e103 dominated habit forme at higher temperatures. &lt;strong&gt;With&#xA;  progressively greater concentrations of organic material a(100)&#xA;  penetration twinning developed, secondary complex nucleation occurred&#xA;  near the twin interfaces, and finally, rosette and rosette-like&#xA;  aggregates formed.&lt;/strong&gt; Higher temperatures generally favored better-formed&#xA;  and larger rosettes. The presence of 5% and 15% NaCl greatly decreased&#xA;  nucleation density and resulted in larger single crystals and crystal&#xA;  aggregates. The a(100) penetation twins appear to be diagnostic of&#xA;  gypsum growth in natural terrestrial sediments at a pH greater than&#xA;  7.5.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Relevant bit about gypsum roses is in &lt;strong&gt;bold&lt;/strong&gt;.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-10-22T07:16:52.400" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12518" PostTypeId="1" CreationDate="2017-10-22T08:38:54.047" Score="1" ViewCount="72" Body="&lt;p&gt;I was lately studying how air masses are generally formed. I came to know that as the warm air rises up and then cools down as it moves above, after some time, a whole cold mass of air is accrued near the equator which leads to the development of air mass. If this is indeed true, then does Hadley cell cause destruction of a potential air mass? Because, it leads to the circulation of the air from the equatorial to the sub-tropical region, which ultimately means that it breaks down the accumulated mass of the cold air and hence prevents the formation of an air mass.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kindly enlighten me with the truth!&lt;/p&gt;&#xA;" OwnerDisplayName="user11312" LastActivityDate="2017-10-22T08:38:54.047" Title="Is the Hadley cell a problem for the air mass?" Tags="|climatology|air-currents|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12522" PostTypeId="1" AcceptedAnswerId="12525" CreationDate="2017-10-23T01:11:45.773" Score="3" ViewCount="118" Body="&lt;p&gt;Is &lt;a href=&quot;https://en.wikipedia.org/wiki/Evapotranspiration&quot; rel=&quot;nofollow noreferrer&quot;&gt;evapotransporation&lt;/a&gt; accounted for in climate models, or is it considered so insignificant that it's not considered?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could additional crops being planted within the last 100 to 50 years account for additional moisture in the air now?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sorry, here's some more background.  I recently attended a conference in which there were 2 speakers, one from NOAA and another from the USACE, that both came to the same conclusion that our atmosphere is becoming more 'wet'.  In particular the NOAA scientist compared the last 50 years to the fifty years prior to that.  So by comparing the last fifty years to the 50 years prior to that it looks like the atmosphere is becoming wetter.  I just wonder, if there were more crops in the ground in the last 50 years, what impact that would have on the climate becoming wetter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have done some googling on this matter and am finding mostly information on how a changing climate may effect evapotransporation but not vice versa.  I also checked out the USDA website for acres planted over time and I'm not finding much further back that a decade or so.  &lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastEditorDisplayName="user11318" LastEditDate="2017-10-23T11:15:16.857" LastActivityDate="2017-10-23T15:37:04.113" Title="Is evapotransporation accounted for in climate models?" Tags="|climate-change|climate|climate-models|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12523" PostTypeId="1" CreationDate="2017-10-23T10:26:58.107" Score="2" ViewCount="54" Body="&lt;p&gt;I am using a mesoscale model to simulate a tropical cyclone. The model input file has an option of 'Frequency of Radiation Tendencies update time' for Longwave and Shortwave radiation. According to me, all the parametrization schemes are updated at every time step,then why is it mentioned separately and how will it work? My question might be vary basic but instead of having the codes, I am unable to visualize what is happening with the radiation parametrization in my model.&#xA;Is there any tutorial where I can get its clear description?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am also searching for a tutorial for TC simulation where the basic steps to simulate a TC are given for beginners. It will be of great help if I can get it here.&lt;/p&gt;&#xA;" OwnerUserId="11162" LastActivityDate="2017-11-22T12:31:55.957" Title="Role of radiation parametrization update frequency in Tropical Cyclone simulation" Tags="|atmosphere-modelling|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12524" PostTypeId="2" ParentId="12523" CreationDate="2017-10-23T11:55:13.717" Score="2" Body="&lt;p&gt;Parameterizations are not usually updated at every time step, generally speaking. Radiation parameterization, in particular, is the most computationally expensive parameterization, since it calculates the integral of an exponential of an integral.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what happens is you set a frequency to update the radiation parameterization, say every 30 minutes. So your model wiil find the diabatic heating tendencies from the initial state and use that for the first 30 minutes of model-time. After the first 30 minutes of model time, the parameterizations recalculate the diabatic tendencies based on the model values (such as clouds, etc). The shorter the timestep, the more you will account for changing model conditions. In short, it is how frequently the radiation parameterization is invoked.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So for example, if you are modeling your tropical cyclone, and you have the update frequency for too long of a time, you could be heating a place like the eye is passing over it, but the eye has already moved.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The shorter the frequency, the more the radiation will adapt to the model state, but at the cost of computational time.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-10-23T11:55:13.717" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12525" PostTypeId="2" ParentId="12522" CreationDate="2017-10-23T15:37:04.113" Score="4" Body="&lt;p&gt;Now most models include changes in evapotranspiration, it is usually grouped together with a few other factors (like draining wetlands) under the heading &quot;Land Usage&quot;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now the question does &quot;Could additional crops being planted within the last 100 to 50 years account for additional moisture in the air now&quot; the answer is no, not by itself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get more moisture into the air long term you need the air to be warmer, otherwise it just rains it out. Another issue is &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1111/j.1466-8238.2010.00587.x/abstract;jsessionid=E1A4E2C068F53201A0C6DF9ACAEFE376.f02t03&quot; rel=&quot;nofollow noreferrer&quot;&gt;different crops&lt;/a&gt; affect evapotranspiration in different ways. For instance irrigation induced evapotranspiration, likely the largest evapotranspiration effect, may actually have a cooling effect, by &lt;a href=&quot;https://pubs.giss.nasa.gov/abs/co04700w.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;increasing cloud cover and precipitation&lt;/a&gt;. Lastly land usage is only a &lt;a href=&quot;https://data.giss.nasa.gov/modelforce/&quot; rel=&quot;nofollow noreferrer&quot;&gt;small&lt;/a&gt; impact not counting the increased greenhouse gas emission it can cause. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2017-10-23T15:37:04.113" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12526" PostTypeId="2" ParentId="12512" CreationDate="2017-10-23T16:07:38.110" Score="1" Body="&lt;p&gt;There are two issues (and one optimization) with/for the code above:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Array indexing starts with &lt;code&gt;0&lt;/code&gt; (not &lt;code&gt;1&lt;/code&gt;) in Python. Therefore, it should be &lt;code&gt;if data[0,m] == countries[i,j]:&lt;/code&gt; because you are interested in the first row;&lt;/li&gt;&#xA;&lt;li&gt;&lt;code&gt;m&lt;/code&gt; goes from &lt;code&gt;0&lt;/code&gt; to 1 (&lt;code&gt;for m in xrange(0,1):&lt;/code&gt;) but it should go from &lt;code&gt;0&lt;/code&gt; to &lt;code&gt;number_of_countries&lt;/code&gt; so that all columns of the energy are iterated. &lt;/li&gt;&#xA;&lt;li&gt;The order of the &lt;code&gt;n&lt;/code&gt; and &lt;code&gt;m&lt;/code&gt; for loops seems to be quite ineffective. Better would be: &lt;code&gt;for m ...: if data[1,m] == ...: for n in ...: nc.variables...=....&lt;/code&gt; Or replace latter for loop by &lt;code&gt;nc.variables[&quot;energy&quot;][:,i,j]=data[:,m]&lt;/code&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;This could work (please improve =&gt; community Wiki) but I cannot test it due to missing input data:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;y = nc.createDimension(&quot;y&quot;, 950)  #y&#xA;x = nc.createDimension(&quot;x&quot;, 1000) #x&#xA;time = nc.createDimension(&quot;time&quot;, 87648) #time&#xA;&#xA;latitude=nc.createVariable(&quot;y&quot;, &quot;f8&quot;, (&quot;y&quot;, ))&#xA;longitude=nc.createVariable(&quot;x&quot;, &quot;f8&quot;, (&quot;x&quot;, ))&#xA;time = nc.createVariable(&quot;time&quot;,&quot;f8&quot;,(&quot;time&quot;,))&#xA;countries = nc.createVariable(&quot;countries&quot;, &quot;f8&quot;, (&quot;y&quot;, &quot;x&quot;));&#xA;energy = nc.createVariable(&quot;energy&quot;, &quot;f8&quot;, (&quot;time&quot;, &quot;y&quot;, &quot;x&quot;), &#xA;                           fill_value=-9999, chunksizes=(1, 950, 1000));&#xA;&#xA;time.standard_name='time'&#xA;time.units ='hours since 2006-01-01 00:00:00.0'&#xA;time.calendar='proleptic_gregorian'&#xA;&#xA;lats =  np.arange(5497500,747500,-5000)    #y  &#xA;lons =  np.arange(2502500,7502500,5000)    #x &#xA;&#xA;# Fill variables&#xA;latitude[:] = lats&#xA;longitude[:] = lons&#xA;&#xA;countries [:]=value&#xA;&#xA;for i in xrange(0,950):  # grid rows&#xA;    for j in xrange(0,1000):    # grid columns&#xA;        for m in xrange(0,int(max(countries))):    # countries&#xA;            if data[0,m] == countries[i,j]:   #correspondance&#xA;                nc.variables[&quot;energy&quot;][:,i,j]=data[1:87648,m]&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2017-10-23T16:07:38.110" CommentCount="0" CommunityOwnedDate="2017-10-23T16:07:38.110" ContentLicense="CC BY-SA 3.0" />
  <row Id="12527" PostTypeId="1" AcceptedAnswerId="12933" CreationDate="2017-10-23T19:36:03.153" Score="8" ViewCount="895" Body="&lt;p&gt;I read the &lt;a href=&quot;http://www.unidata.ucar.edu/blogs/developer/entry/netcdf_compression&quot; rel=&quot;noreferrer&quot;&gt;doc&lt;/a&gt; but still have no idea about &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;what are the advantages to enable or disable the shuffle, &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;what level [0-9] of compression is optimal, &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;what's the best choice of chunk size?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="3047" LastActivityDate="2017-12-19T10:52:15.983" Title="Regarding compression, shuffle filter of netcdf4" Tags="|meteorology|oceanography|data-formats|netcdf|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12531" PostTypeId="1" CreationDate="2017-10-24T11:59:11.790" Score="4" ViewCount="142" Body="&lt;p&gt;I am about to perform a Loss On Ignition test on a material I know that contains among on things kaolinite, which will release water at 500 $^oC$. However, I tried finding a table with decomposition temperatures of common minerals that lose their water, or carbon, or whatever, at a certain temperature or temperature interval.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyone familiar with a freely accessible table? &lt;/p&gt;&#xA;" OwnerUserId="11323" LastActivityDate="2017-11-23T12:39:47.473" Title="Is there a table with decomposition temperatures of common minerals?" Tags="|mineralogy|minerals|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12532" PostTypeId="2" ParentId="12531" CreationDate="2017-10-24T12:21:11.017" Score="1" Body="&lt;p&gt;I would have expected to find something &lt;a href=&quot;https://www.engineeringtoolbox.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; but there isn't a guide to ceramics there that I can find. This &lt;a href=&quot;http://ousar.lib.okayama-u.ac.jp/files/public/1/15437/20160527210146171135/Mem_Fac_Eng_OU_28_1_51.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;article&lt;/a&gt; and it's references may give you some guidance though. Found a limited table in &lt;a href=&quot;http://www.springer.com/cda/content/document/cda_downloaddocument/9783540312109-c1.pdf?SGWID=0-0-45-174599-p115687972&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; that will probably help too.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2017-10-24T12:21:11.017" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12533" PostTypeId="1" CreationDate="2017-10-25T05:01:58.913" Score="1" ViewCount="67" Body="&lt;p&gt;Does anyone have experience with modelling seawater intrusion scenarios in Feflow?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In my models, my mass-concentration seems to drive up into the unsaturated vadose zone, which I don't believe is correct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm using Feflow v7.1 with Richards unsaturated flow equations.&lt;/p&gt;&#xA;" OwnerUserId="6181" LastEditorUserId="10681" LastEditDate="2017-10-26T00:58:05.217" LastActivityDate="2017-10-26T00:58:05.217" Title="Modelling the unsaturated zone in FeFlow in seawater intrusion scenarios" Tags="|hydrology|groundwater|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12534" PostTypeId="2" ParentId="668" CreationDate="2017-10-25T05:53:21.560" Score="0" Body="&lt;p&gt;In addition to the answer by @Kaberett lapse rate explains the height variation of the tropopause quite well.   Lapse rate is a property of gravity and the ideal gas law and it has to be adjusted for circulation and condensation and the top-down heating from the sun, which is a small effect given a mostly transparent atmosphere.   Lapse rate isn't perfect, but it's still good for an approximation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Lapse_rate#Convection_and_adiabatic_expansion&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia summary&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shorter, &lt;a href=&quot;https://www.britannica.com/science/adiabatic-lapse-rate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Britannica summary&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the Britannica summary:   &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The lapse rate of nonrising air—commonly referred to as the normal, or&#xA;  environmental, lapse rate—is highly variable, being affected by&#xA;  radiation, convection, and condensation; it averages about 6.5 °C per&#xA;  kilometre (18.8 °F per mile) in the lower atmosphere (troposphere).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;If we take that averaged 6.5°C per km, that explains pretty close to the surface temperature variation on the Earth at sea level.  (Antarctica, being mostly more than a mile in elevation, you need to adjust the temperature -6.5°C per km in altitude for surface temperature).   The troposphere being an average of 8 km higher at the equator, corresponds to 52°c variation using that -6.5 degree estimate, or about 32 degrees (equator) to minus 20 (pole), which is very much in the ballpark.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, as noted in the Wikipedia article&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the dry adiabatic lapse rate is a constant 9.8 °C/km (5.38 °F per&#xA;  1,000 ft, 3 °C/1,000 ft), the moist adiabatic lapse rate varies&#xA;  strongly with temperature. A typical value is around 5 °C/km&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Moist air has a lower lapse rate, which explains why the troposphere is highest over warm equatorial Pacific and why it peaks over monsoons. - see &lt;a href=&quot;http://www-das.uwyo.edu/~geerts/cwx/notes/chap01/tropo.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's the surface temperature and water vapor.  That's the gist of it.  The rotation of the Earth can't account for a troposphere that's twice as high over the equator.  The rotation of the Earth (and if we want to get silly, also the Moon's atmospheric tidal bulges) both affect the troposphere some, but they are minor players.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth's atmosphere shouldn't bulge much more than it's body, about &lt;a href=&quot;https://en.wikipedia.org/wiki/Equatorial_bulge#Other_celestial_bodies&quot; rel=&quot;nofollow noreferrer&quot;&gt;1 part in 298&lt;/a&gt;, even if you multiply that by 4, and I think that's too aggressive a mathematical approach, but even so, that would be less than 1 part in 70 of atmospheric expansion over the equator due to the spin of the Earth.  That's very far from the doubling that temperature explains.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2958" LastEditDate="2019-04-18T11:22:04.177" LastActivityDate="2019-04-18T11:22:04.177" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="12535" PostTypeId="2" ParentId="2267" CreationDate="2017-10-25T07:04:11.007" Score="0" Body="&lt;p&gt;In addition to the answer above (and I realize this is an old question and perhaps better for world building), but what we know about climate, some subtle changes can have pretty big effects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you increase the axial tilt a few degrees that would make the variation in sunlight winter to summer greater and would make colder winters and warmer summers, but the effect of warmer summers is that glaciers would have a harder time growing.  You could also increase the planet's greenhouse gas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could also create more ocean surface area and less land.   Oceans are good temperature stabilizers and with strong ocean currents, you might get a year-round warm water flow towards the continent on the pole, leading to a warming of the land on the pole, much the same way Europe is warmer than similar latitudes in other places on earth, due to the warm mid Atlantic current.  More ocean surface area and a strong oceanic conveyor might be the simplest explanation, creating a regular stream of warm air that blows onto your continent on the pole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or you could give the planet a slower rotation and longer days (colder nights), but during the summer, snow would melt during the longer day - also preventing glacial buildup.  For your scenario, glaciers on Mountains is fine, but you don't want glaciers spreading across land like we have in Greenland and Antarctica.   For a warmer pole continent, you need some combination of effects that would prevent glacial growth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Glacial growth on land and a decline in oceanic circulation is thought to be the cause of the ice age period that began about 2.6 million years ago.   Similarly, land over the pole is thought to be what lead to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Karoo_Ice_Age&quot; rel=&quot;nofollow noreferrer&quot;&gt;Karoo ice age&lt;/a&gt;.   You'd need a mechanism to make your land on the pole warmer (like some of the mechanisms above).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On river runoff:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;River water usually (&lt;a href=&quot;http://www.bbc.com/earth/story/20160516-why-it-is-hard-to-find-the-source-of-rivers-like-the-amazon&quot; rel=&quot;nofollow noreferrer&quot;&gt;but not always&lt;/a&gt;) requires snow melt.  If you have a lot of snow that melts over the year (like &lt;a href=&quot;https://www.internationalrivers.org/campaigns/the-himalayas&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Himalayas&lt;/a&gt;), that would create a lot of large rivers but I don't think those rivers would warm the land very effectively.  Rivers respond to land temperature and snow/ice melt and weather patterns, more than they control them.   Other methods like more greenhouse gas, a bigger ocean with a strong conveyor or some orbital changes are the best methods I can think of for your scenario.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2017-10-25T07:04:11.007" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12536" PostTypeId="1" CreationDate="2017-10-25T07:40:52.523" Score="2" ViewCount="92" Body="&lt;p&gt;I am trying to use BASINS 4.1 software to prepare input file for HSPF (.uci). When I launch HSPF from BASINS software, I have to direct the sofware to read a time series file (.wdm). In my case I am unable to tell the sofware to do this because the 'met stations' tab is not providing me the option to do this. I am having complete blank 'met stations' tab. Anyone has any ideo how to fix this problem? Or is there any other way to prepare input file for HSPF (.uci file) without using BASINS?&lt;a href=&quot;https://i.stack.imgur.com/kT3wf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kT3wf.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5557" LastActivityDate="2017-10-26T02:11:32.863" Title="Unable to prepare input file for HSPF software for watershed modeling!" Tags="|hydrology|software|watershed|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12537" PostTypeId="2" ParentId="9962" CreationDate="2017-10-25T11:53:14.753" Score="4" Body="&lt;p&gt;I recommend following two books. I am not sure it will answer all the questions you have mentioned but I think together they will answer most of them. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;strong&gt;The discovery of global warming&lt;/strong&gt; by &lt;strong&gt;Spencer Weart&lt;/strong&gt; &lt;a href=&quot;http://www.worldcat.org/title/discovery-of-global-warming/oclc/51505599&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.worldcat.org/title/discovery-of-global-warming/oclc/51505599&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;The Weather Makers&lt;/strong&gt; by &lt;strong&gt;Tim Flannery&lt;/strong&gt; &lt;a href=&quot;http://www.worldcat.org/oclc/80331702&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.worldcat.org/oclc/80331702&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Both the books are highly readable for non-expert audience. Both the books do good job in educating readers about scientific aspect of the problem without bogging down them with equations or technical jargon.  The first book's focus is on science aspect of the climate-change problem and told in highly engaging style, the second book's focus is on mitigation aspect in equally engaging style. &lt;/p&gt;&#xA;" OwnerUserId="10780" LastActivityDate="2017-10-25T11:53:14.753" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12538" PostTypeId="1" CreationDate="2017-10-25T14:33:49.187" Score="3" ViewCount="168" Body="&lt;p&gt;I have very small mineral samples, and I'm looking for a glue that can hold them through a sample preparation process that I'm doing: heating, polishing, and measuring magnetic moment. For that I want the glue to have 3 criteria:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;heat resistant (over 600 Celsius)&lt;/li&gt;&#xA;&lt;li&gt;can hold through polishing (therefore can't dissolve in water)&lt;/li&gt;&#xA;&lt;li&gt;very important: that it won't acquire magnetic moment after being in an external field, since I want to measure very weak magnetic moment from my samples.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I tried AREMCO Ceramabond 569. My measurements showed that it does acquire a  magnetic moment when exposed to an external magnetic field (it was recommended by the company).&lt;/p&gt;&#xA;" OwnerUserId="11327" LastEditorUserId="94" LastEditDate="2017-10-25T20:24:12.433" LastActivityDate="2017-11-24T20:43:24.903" Title="Is there a high-temperature, non-magnetic glue that doesn't dissolve in water?" Tags="|geology|geophysics|laboratory|rock-magnetism|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12539" PostTypeId="2" ParentId="7165" CreationDate="2017-10-25T15:43:59.853" Score="0" Body="&lt;p&gt;The definition of barotropic is that density depends only on pressure.  The definition of baroclinic is that density can depend on other variables.  This in itself is not particularly useful for understanding what baroclinic and barotropic flow means.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the context of the ocean, water is pretty much incompressible, so density will be virtually constant for a barotropic ocean.  Hence there is no stratification for a barotropic ocean, and the only waves the fluid can support are at the interface with the air.  On the other hand, if the fluid is baroclinic (density depending on non-constant temperature, and also salinity), then there can be internal gravity waves caused by a change in density in the z-direction.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the atmosphere, air is relatively compressible.  Hence if the atmosphere is barotropic, it means that the only density changes are due to pressure. Hence temperature is horizontally constant and there is no thermal wind shear in the vertical.  This is a more reasonable assumption in the tropics than in the midlatitudes.  &lt;/p&gt;&#xA;" OwnerUserId="11328" LastActivityDate="2017-10-25T15:43:59.853" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12540" PostTypeId="2" ParentId="12538" CreationDate="2017-10-25T16:16:03.067" Score="2" Body="&lt;p&gt;Your question is quite similar to &lt;a href=&quot;https://earthscience.stackexchange.com/q/1035/94&quot;&gt;one that I asked&lt;/a&gt; some time ago, with the additional requirement that the glue be insoluble in water, which unfortunately excludes sodium and potassium silicate. Like you, I've found Ceramabond (albeit 571, not 569, in my case) to be too magnetic. I suspect that there's an element of random variation here. It's not (as far as I know) specifically formulated to be completely non-magnetic, so there may be some batches which are more magnetic than others. Khakhalova and Feinberg (2014) investigated some other high-temperature ceramic adhesives and found that they were also too magnetic for use with weakly magnetic samples. However, they do make one useful suggestion:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It may be possible for rock and paleomagnetic labs to reduce the concentration of magnetic contamination in Omega cements, for&#xA;  example, by sending the powder through a very clean Franz magnetic separator&#xA;  multiple times.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I haven't yet heard of anyone actually doing this, but it certainly seems worth trying. They also write that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We’ve contacted Omega Engineering Inc. regarding the iron concentrations in their&#xA;  cements and their technical staff are&#xA;  currently exploring whether it would be&#xA;  possible to produce a high purity, high&#xA;  temperature cement specifically for rock&#xA;  magnetic and paleomagnetic applications.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I don't know if anything has come of those attempts in the three years since the article was published, but you could email the authors and/or Omega to find out.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Khakhalova, Evgeniya and Feinberg, Josh M. (2014).&#xA;The iron that binds: The unexpectedly strong magnetism of high-temperature ceramic cements commonly used in rock magnetic experiments. &lt;em&gt;IRM Quarterly&lt;/em&gt;, 24(2), url: &lt;a href=&quot;http://www.irm.umn.edu/quarterly/irmq24-2.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.irm.umn.edu/quarterly/irmq24-2.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="94" LastActivityDate="2017-10-25T16:16:03.067" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12542" PostTypeId="1" AcceptedAnswerId="12543" CreationDate="2017-10-25T20:19:53.280" Score="1" ViewCount="558" Body="&lt;p&gt;I need some help identifying this fossil.  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;I found the rock 30 years ago along the Cuyahoga River in northern Ohio.&#xA;Northern Ohio is glaciated so it is possible that the specimen was transported to Ohio. &lt;/li&gt;&#xA;&lt;li&gt;The rock is approx 1.5 x 2.5 inches (3.8 cm x 6.3 cm).  &lt;/li&gt;&#xA;&lt;li&gt;The rock is calcareous reacting to HCL. &lt;/li&gt;&#xA;&lt;li&gt;The rock feels the correct weight for its size. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1kaDt.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1kaDt.jpg&quot; alt=&quot;Front view&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/MteEb.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MteEb.jpg&quot; alt=&quot;Side view&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T16:28:52.937" LastActivityDate="2019-08-29T16:28:52.937" Title="What type of fossil is this found at northern Ohio?" Tags="|fossils|paleontology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="12543" PostTypeId="2" ParentId="12542" CreationDate="2017-10-25T20:22:35.783" Score="2" Body="&lt;p&gt;Of course 5 minutes after I post the question, I find the answer myself:&#xA;Halysites (Chain Coral) fossil extinct coral from the Silurian period.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="1149" LastEditDate="2018-01-12T17:35:06.003" LastActivityDate="2018-01-12T17:35:06.003" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12545" PostTypeId="2" ParentId="12536" CreationDate="2017-10-26T02:11:32.863" Score="2" Body="&lt;p&gt;I have found the solution and it seems that in BASINS 4.1, user has to import wdm file before launching HSPF by going to 'File' and then to either 'import data' or 'manage data'.  Once this step is done, BASINS 'understands' that there is a wdm file and then the user can add the wdm file from 'met stations' tab. &#xA;The tutorials on epa site correspond to BASINS 4.0 and in BASINS 4.0, one doesn't have to go through the so call 'import data' step before launching HSPF. &lt;/p&gt;&#xA;" OwnerUserId="5557" LastActivityDate="2017-10-26T02:11:32.863" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12546" PostTypeId="1" CreationDate="2017-10-26T02:14:19.367" Score="5" ViewCount="817" Body="&lt;p&gt;From what reference point/level are prehistorical (e.g., Precambrian era) sea levels estimated?  As I understand things, the following are true:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Since the formation of continents, land elevations everywhere have been continually changing due to plate tectonics, weathering, sedimentation, etc.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The total volume of ocean water has been essentially the same since formation in the early Hadean.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Water seeks its own level.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;So is the rise and fall of sea level derived from the geological record measured relative to the adjacent land, or the center of the earth, or what?&lt;/p&gt;&#xA;" OwnerUserId="11172" LastEditorUserId="18081" LastEditDate="2022-08-04T08:39:38.907" LastActivityDate="2022-08-04T08:39:38.907" Title="estimation of prehistoric sea levels" Tags="|sea-level|paleogeography|bathymetry|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12547" PostTypeId="2" ParentId="12500" CreationDate="2017-10-26T04:01:28.643" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;So all this leading to my question: What could have been the cause of&#xA;  the this deep divide?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Think about what animals need to travel between Islands.  It's very difficult unless the water between the islands either drops or freezes over (Deer, for example, have crossed from New Jersey to Staten Island when the Hudson River freezes over), but the ocean doesn't freeze near the Wallace line.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or, during ice ages &lt;a href=&quot;https://en.wikipedia.org/wiki/Last_Glacial_Maximum#World_impact&quot; rel=&quot;nofollow noreferrer&quot;&gt;when sea level falls as much as 410 feet&lt;/a&gt;, Islands can be joined as sea level drops.   Japan, for example, a &lt;a href=&quot;http://www.evanseasyjapanese.com/where-the-ice-age-was.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;land-bridge formed through Hokaido to mainland Asia.&lt;/a&gt;  Likewise, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Doggerland&quot; rel=&quot;nofollow noreferrer&quot;&gt;UK connects to France&lt;/a&gt; and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Beringia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bering Straight&lt;/a&gt; becomes land as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's nothing particularly remarkable about the water over the Wallace line other than it being &lt;a href=&quot;https://en.wikipedia.org/wiki/Wallace_Line#Biogeography&quot; rel=&quot;nofollow noreferrer&quot;&gt;too deep for any land bridges&lt;/a&gt; to form during ice ages.  The relevant geological feature for land bridges is shallow oceans/seas/bays/straights/channels, etc.   The Java sea is sufficiently shallow that all the islands Northwest of the Wallace line are joined when sea level falls.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It was pointed out that it's rough water too, but that's not the primary reason.   The primary reason is simply the ocean's depth and width.  Animals have little incentive to try to cross any fairly large body of ocean.  Animals sometimes migrate across raging rivers, but in that situation the other side is clearly visible.  The islands on each side of the Wallace line, even with the sea level drop, would (&lt;em&gt;I assume&lt;/em&gt;), appear very far away to the eye, if they could be seen at all.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2017-10-26T04:01:28.643" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12548" PostTypeId="1" AcceptedAnswerId="12549" CreationDate="2017-10-26T04:12:45.897" Score="2" ViewCount="150" Body="&lt;p&gt;Where on Earth do we expect to find very old groundwater (infiltrated thousands of years ago)?&lt;/p&gt;&#xA;" OwnerUserId="11332" LastEditorUserId="94" LastEditDate="2017-10-26T08:55:09.817" LastActivityDate="2017-10-26T17:12:24.633" Title="Where on Earth does paleo-groundwater exist?" Tags="|groundwater|hydrogeology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12549" PostTypeId="2" ParentId="12548" CreationDate="2017-10-26T13:05:33.323" Score="1" Body="&lt;p&gt;In large intracontinental basins where the main rock formations are exposed in adjoining highlands and rare deeply buried within the basin itself.  The Madison Limestone is an example.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Madison and its equivalent strata extend from the Black Hills of western South Dakota to western Montana and eastern Idaho, and from the Canada–United States border to western Colorado and the Grand Canyon of Arizona.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;https://en.wikipedia.org/wiki/Madison_Group&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ground-water ages vary from virtually modern to&#xA;about 23,000 yr. The 14C ages indicate flow velocities of&#xA;between 7 to 87 ft/yr. Hydraulic conductivities based on&#xA;average carbon-14 flow velocities are similar to those&#xA;based on digital simulation of the flow system (Downey,&#xA;1984).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From: &lt;a href=&quot;https://pubs.usgs.gov/pp/1273f/report.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geochemical Evolution of Water in the&#xA;Madison Aquifer in Parts of Montana,&#xA;South Dakota, and Wyoming&#xA;By JOHN F. BUSBY, L. NIEL PLUMMER, ROGER W. LEE, andEWJCE B. HANSHAW&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-10-26T13:05:33.323" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12550" PostTypeId="1" CreationDate="2017-10-26T13:26:35.793" Score="0" ViewCount="53" Body="&lt;p&gt;Let's say I have an infared picture of the earth from the space station, is it possible to measure the temperature of the picture area, and thus convert the infared picture I have to a thermal picture?&lt;/p&gt;&#xA;" OwnerUserId="11335" LastEditorUserId="3309" LastEditDate="2017-10-27T13:29:07.767" LastActivityDate="2017-10-27T13:29:07.767" Title="Infared &amp; Thermal imaging" Tags="|meteorology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12552" PostTypeId="1" CreationDate="2017-10-26T14:33:13.017" Score="2" ViewCount="52" Body="&lt;p&gt;I just came back from the Grand Canyon, and it's awesome. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, my friend and I did notice something - it seems that there's some kind of haze in the far horizon that seems worse as the sun rises to noon. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One interesting bit is that a polarizer can clean it up when we take photos, so that suggests it's reflected light.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regardless, I'm curious, is that just pollution blown into the area? or some other atmospheric feature that I didn't know about&lt;/p&gt;&#xA;" OwnerUserId="11337" LastActivityDate="2017-11-01T15:30:55.177" Title="Haze in Arizona / Grand Canyon that gets more apparent around noon - smog or something else?" Tags="|meteorology|air-pollution|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12554" PostTypeId="2" ParentId="12548" CreationDate="2017-10-26T17:12:24.633" Score="1" Body="&lt;p&gt;Virtually every oil / gas well contains old water. However , surface water , mixed with produced water, is injected in some to facilitate production .Last number I saw was that onshore wells in the US averaged 90 % water in the liquid phases.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2017-10-26T17:12:24.633" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12555" PostTypeId="2" ParentId="12546" CreationDate="2017-10-26T20:03:50.727" Score="-1" Body="&lt;p&gt;First there are many ways of estimating sea level, you will have to examine a specific paper to see what they use. As a rule of thumb &lt;strong&gt;global sea level is usually measured relative to current sea level in paleoclimate studies&lt;/strong&gt; this is &lt;em&gt;confusingly&lt;/em&gt; an absolute measure, usually eustatic (volume of the ocean water). Keep in mind sea level is different across the planet's surface when measured from the center of the planet thanks to spin and gravity anomalies so there is no absolute measure of height, so instead volume is used. There are of course many relative measures of sea level but this is more referring to sea depth than anything else and thus are local effects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second if you haven't guessed, &lt;strong&gt;the volume of the ocean is not constant&lt;/strong&gt; it changes quite a bit, both the volume of the water and the volume being occupied, the volume of the container if you will. The mass is more constant (on the scale being measured) but even then influenced by removing or adding water. Many measures of sea level are &lt;strong&gt;eustatic&lt;/strong&gt;, meaning they are measuring change in the volume of the ocean. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;On the global level there are two big issues influencing sea level, temperature and available water&lt;/strong&gt;(mostly ice caps).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The temprature has a big effect due to thermal expansion, change the temprature and the volume of water changes even if the mass is the same. Most of the our current sea level rise is due to thermal expansion not melting glaciers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second is if there are ice caps and how big they are, since ice frozen on land is not in the ocean. The earth right now  basically has only one ice cap (antarctica). Icecaps are largely controlled by whether their are continents near the poles. Isolated dry basins that flood can have a similar effect by increasing the area that needs to be filled, for instance when the mediterranean flooded it is &lt;a href=&quot;http://www.nature.com/nature/journal/v462/n7274/full/nature08555.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;estimated&lt;/a&gt; to have dropped global sea level (of the rest of the ocean) by ~ 9 meters in a about a year or two, which may be one of the most dramatic change in history, and probably scared the crap out of the humans around at the time. The drop is caused by increasing the volume being filled without changing the volume of water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are lots of smaller and/or local effects that can change sea level or local sea level and wiki has a decent chart of them &lt;a href=&quot;https://en.wikipedia.org/wiki/Past_sea_level&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, these include age of the oceanic plates, plate rebound, and intercontinental reservoirs.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2017-10-28T23:07:23.990" LastActivityDate="2017-10-28T23:07:23.990" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12556" PostTypeId="1" CreationDate="2017-10-26T20:08:11.963" Score="10" ViewCount="762" Body="&lt;p&gt;During a nature walk inside an old abandoned quarry I stumbled upon strange spirals that appear to be naturally formed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What could cause this spiral formation? Is it a known phenomena?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FGPdH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FGPdH.jpg&quot; alt=&quot;Earth spiral 1&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WjLte.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WjLte.jpg&quot; alt=&quot;Earth spiral 2&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To clarify , the images are from the same place , but made with difference of couple of days. I took the photos during Winter time in Israel.&lt;br&gt;&#xA;The Quarry was abandoned decades ago, so i don't think that this is a result of the working equipment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also i have been looking at photos of &lt;a href=&quot;https://en.wikipedia.org/wiki/Crop_circle&quot; rel=&quot;nofollow noreferrer&quot;&gt;crop circles&lt;/a&gt; but it looks like the two are not related.&lt;/p&gt;&#xA;" OwnerUserId="11341" LastEditorUserId="11341" LastEditDate="2017-11-02T07:52:01.383" LastActivityDate="2017-11-04T00:29:35.337" Title="Natural spiral pattern of grass - what could cause this?" Tags="|geomorphology|vegetation|" AnswerCount="3" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="12559" PostTypeId="2" ParentId="12550" CreationDate="2017-10-27T12:50:23.330" Score="1" Body="&lt;p&gt;Temperature images are calculated from microwave and infrared data. So in principle yes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;https://en.wikipedia.org/wiki/Satellite_temperature_measurements?wprov=sfla1&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Satellite_temperature_measurements?wprov=sfla1&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3309" LastActivityDate="2017-10-27T12:50:23.330" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12560" PostTypeId="1" CreationDate="2017-10-28T08:50:50.227" Score="3" ViewCount="52" Body="&lt;p&gt;I am using the numerical weather prediction (NWP) model RAMS to simulate a Tropical Cyclones in BoB region. I made two setups with two Cumulus Parametrization schemes (Kuo and KF). Initial and boundary conditions data were generated from NCEP FNL analysis data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here, I am facing a problem of getting NaN values of aerosol/microphysics variables with both the schemes. With the KF scheme, these are obtained at an early stage i.e. at time of KF CP update time (or twice of this time). Whereas, the Kuo scheme provides this error after 3 hours of model initialization.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Initially, I thought that this might be due to the 'timestep'. I rechecked it many times by increasing and decreasing its value but the problem persisted. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also checked the microphysics parameters set according to my knowledge, I could not find the cause of this error.&lt;/p&gt;&#xA;" OwnerUserId="11162" LastEditorUserId="5594" LastEditDate="2017-10-28T18:55:15.173" LastActivityDate="2017-10-28T18:55:15.173" Title="NaN values of aerosol variables in KF/Kuo parametrization schemes" Tags="|atmosphere-modelling|tropical-cyclone|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12561" PostTypeId="1" AcceptedAnswerId="12583" CreationDate="2017-10-28T15:46:33.183" Score="1" ViewCount="81" Body="&lt;p&gt;In the &lt;a href=&quot;https://earthscience.stackexchange.com/a/8245/11353&quot;&gt;answer to &quot;Why is ground water rising on these forest rings?&quot;&lt;/a&gt; it is written: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;these rings are too numerous and too regular in shape to be related to either kimberlites or (even more bizarrely) Oklo-type natural nuclear reactors&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;How is the regularity of forest rings assessed? How many near-rings and other shapes have been found?&lt;/p&gt;&#xA;" OwnerUserId="11353" LastActivityDate="2017-10-30T21:56:02.233" Title="Forest rings shape regularity" Tags="|geophysics|forest|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12562" PostTypeId="1" AcceptedAnswerId="12563" CreationDate="2017-10-28T18:08:47.000" Score="1" ViewCount="27716" Body="&lt;p&gt;In my region wind speed increases in Autumn. It reaches to 30 km/h with gust up to 40 km/h. I want to know at which speed the wind and gust can cause small damage of the normal window glass (We mostly using PVC for the windows).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tonight I noticed that ventilizer fan damaged due to opposite wind direction and cause to stop. Also, my TV Antenna was completely damaged (I couldn't find it).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to know Wind and Gust speeds that can cause damage to usual house, outdoor cables, antenna, windows?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="11354" LastEditorUserId="6298" LastEditDate="2017-10-29T04:21:14.783" LastActivityDate="2017-10-29T04:21:14.783" Title="What wind speeds and gusts can usually damage houses or trees?" Tags="|wind|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12563" PostTypeId="2" ParentId="12562" CreationDate="2017-10-28T18:31:08.807" Score="5" Body="&lt;p&gt;This Beaufort Scale of Wind Force image may help answer your question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UWfzf.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UWfzf.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;source: strleng.blogspot.com&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2017-10-28T18:31:08.807" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12565" PostTypeId="2" ParentId="12546" CreationDate="2017-10-28T20:10:32.963" Score="5" Body="&lt;p&gt;Short answer:    Nobody knows.   Estimates of post-cambrian water levels are done by studying geology and where shorelines were in the past and what land was under water and working out from that how high the sea level probably was.   There are no pre-cambrian sea level estimates that I know of.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Working out how much water was on the surface of the Earth, especially during the pre-Cambrian era is a difficult subject with much uncertainty.   While the total amount of water on Earth may not have changed too much too much over the last 3 billion years, ground water vs surface water, and the shape of the ocean basin and the role of volcanoes and tectonics add to the uncertainty.   There's still some uncertainty on snowball Earth and if it went all the way down to the equator over the oceans.   Sea level over the pre-cambrian requires working out the specifics of snowball earth.   It's a tricky subject full of uncertainty.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Long answer that also says we basically don't know&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;&lt;em&gt;From what reference point/level are prehistorical (e.g., Precambrian&#xA;  era) sea levels estimated?&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I've never seen a pre-cambrian era estimate on sea level so I don't know how they are estimated.   &lt;a href=&quot;https://en.wikipedia.org/wiki/Sequence_stratigraphy#Sea_level_through_geologic_time&quot; rel=&quot;noreferrer&quot;&gt;This is the oldest I could find&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the article explains, historic sea level is estimated by finding where the shorelines were at geologically historic time periods and looking at what was under water.   There's probably a pretty significant margin of error in those estimates I would think.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Past_sea_level&quot; rel=&quot;noreferrer&quot;&gt;The article&lt;/a&gt; also says&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The main factors affecting sea level are the amount and volume of&#xA;  available water and the shape and volume of the ocean basins. The&#xA;  primary influences on water volume are the temperature of the&#xA;  seawater, which affects density, and the amounts of water retained in&#xA;  other reservoirs like rivers, aquifers, lakes, glaciers, polar ice&#xA;  caps and sea ice. Over geological timescales, changes in the shape of&#xA;  the oceanic basins and in land/sea distribution affect sea level. In&#xA;  addition to eustatic changes, local changes in sea level are caused by&#xA;  tectonic uplift and subsidence.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Over geologic time sea level has fluctuated by hundreds of meters.&#xA;  Today's interglacial level is near historic highs and is 130 meters&#xA;  above the low level reached during the Last Glacial Maximum&#xA;  19,000–20,000 years ago.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, key factors are obviously ice ages and glaciers, as well as the shape of the ocean basin.   The movement of continents affects the shape and depth of the ocean basin, so continental movement likely has an effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a somewhat small but fun example, the Mediterranean Sea has about &lt;a href=&quot;https://en.wikipedia.org/wiki/Mediterranean_Sea&quot; rel=&quot;noreferrer&quot;&gt;3.75 million cubic km of water&lt;/a&gt; in it and the sea is thought to have been a dry valley some 5.33 million years ago that, once the straight of Gibraltar gave way, &lt;a href=&quot;https://en.wikipedia.org/wiki/Zanclean_flood&quot; rel=&quot;noreferrer&quot;&gt;was quickly filled by the Atlantic ocean&lt;/a&gt;.   That's just a theory.  It may have filled much more slowly, and over 5 million years ago, it might have been a significantly different size too, but if we use the 3.75 million cubic km number over today's 361.9 million square km of ocean surface, that works out to a 10 meter drop in sea level to fill up the Mediterranean valley.    10 meters isn't a big change in the grand scheme of things, but if it happened over as little as a year, as one hypotheses suggests, that would have been quite something to observe a 10 meter drop in sea level over a single year or so.   However long the Mediterranean took to fill, it's a nice example of how shifting land can affect sea level. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Historic estimates are made (as noted above) by studying where the shorelines were and studying what was under water and trying to piece together an estimate from that.   Formation of glaciers like the Antarctic Glacier, which would raise sea level 58 meters if it melted, affect sea level too.  The antarctic glacier began to grow in earnest &lt;a href=&quot;https://en.wikipedia.org/wiki/Antarctic_ice_sheet#History&quot; rel=&quot;noreferrer&quot;&gt;about 34 million years ago&lt;/a&gt;.   Greenland is another 6 meters and that formed much later, over the last million years or so.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geological &lt;a href=&quot;https://en.wikipedia.org/wiki/Timeline_of_glaciation#Known_ice_ages&quot; rel=&quot;noreferrer&quot;&gt;history of ice ages&lt;/a&gt; is fairly well understood, though the total amount of water in those glaciers might have some uncertainty.   The shape of the ocean basin is (I think) less well understood over the last 600 million years or so.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ice age periods, 260 to 360 and 420 to 450 million years ago should correspond to drops in the chart, below.  The recent ice age period is just 2.5 million years long, and too short to be well represented but the 34 million years when the antarctic ice formed is apparent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VX8PP.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VX8PP.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;&lt;em&gt;Since the formation of continents, land elevations everywhere have&#xA;  been continually changing due to plate tectonics, weathering,&#xA;  sedimentation, etc.&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The continents formed quite early, &lt;a href=&quot;http://earthsky.org/earth/when-earths-continents-rose-above-its-oceans&quot; rel=&quot;noreferrer&quot;&gt;between 2.5 and 3 billion years ago&lt;/a&gt;.  The silicate rock that form most of the granite that makes up both the continents and the continental plates was present at the formation of the Earth.   Heat and plate tectonics likely helped form the continents.   Life and photosynthesis may have added to them over time, but most of the continental material was present at Earth's formation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Precisely how sea levels change, other than by formation of glaciers or the forming of filling of valleys on land is (to my knowledge) not well understood though the shape of the ocean basin (noted above) plays a key role.   The continents are roughly some 35 miles thick in silicate rock, but that far below the Earth's surface, silicate rock can melt and mix with basalt in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mantle_(geology)#Structure&quot; rel=&quot;noreferrer&quot;&gt;upper mantle&lt;/a&gt;.   We know this because lava can be either basalt rich or silicate rich.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Sequence_stratigraphy#Sea_level_through_geologic_time&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia mentions sediment&lt;/a&gt; and groundwater likely also play roles.  Over long enough periods of time, &lt;a href=&quot;https://en.wikipedia.org/wiki/Rock_cycle&quot; rel=&quot;noreferrer&quot;&gt;the rock cycle&lt;/a&gt; likely returns sediment that erodes of land into the ocean, back to the land.   Likewise, life can lead to the formation of limestone and other carbonate rock, but that's probably a small percentage of total land and a small factor, not a major factor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The internal heat of the Earth (I would guess) play a bigger role.  A hotter earth, the upper mantle is a little closer to the surface and the granite continents and continental plates are less thick, so they float less high on the basalt, leading to a corresponding higher sea level, but that's just speculation on my part.   As Earth cools over hundreds of millions of years, the granite may become thicker and the sea level could drop in relation to the rising land.  This fits with the studies that sea level was generally higher in the past, but, again, this is speculation on my part.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The total volume of ocean water has been essentially the same since&#xA;  formation in the early Hadean.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You probably shouldn't make that assumption.  &lt;a href=&quot;https://en.wikipedia.org/wiki/Hadean&quot; rel=&quot;noreferrer&quot;&gt;The Hadean&lt;/a&gt; was the first epoch all the way back to the formation of the Earth.   For consistent amounts of water, the earliest I would consider starting would be the end of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Late_Heavy_Bombardment&quot; rel=&quot;noreferrer&quot;&gt;late heavy bombardment&lt;/a&gt;, about 3.8 billion years ago.   That would be enough time for the magnetic field to form (&lt;a href=&quot;https://www.smithsonianmag.com/science-nature/earths-magnetic-field-least-four-billion-years-old-180956114/&quot; rel=&quot;noreferrer&quot;&gt;about 4 billion years ago&lt;/a&gt;) and time for the sun to settle down, because UV rays from the young sun can strip water form Earth by &lt;a href=&quot;https://www.britannica.com/science/photochemical-reaction&quot; rel=&quot;noreferrer&quot;&gt;photo-chemical dissociation&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Throughout the history of Earth, UV rays from the sun have stripped hydrogen from atmospheric water vapor, effectively taking water away from Earth and replacing it with hydroxide, which is fairly reactive.   Likewise, comets and asteroids that hit the Earth bring water with them.   The current rate is quite small and insignificant, but 3.8 billion years ago, even after the late heavy bombardment, there might still have been frequent enough comet impacts to affect sea level over different eras.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Precise numbers aren't known - &lt;a href=&quot;https://physics.stackexchange.com/questions/297622/is-the-earth-gaining-or-losing-mass-over-time&quot;&gt;question on that here&lt;/a&gt;.   But if Earth loses 50,000 tons of mass per year, most of that hydrogen stripped from water, that's as much as 900,000 tons of water photo-disintegrated per year.   Over a billion years, that's 900 trillion tons of water, which sounds like a lot, but it's less than 1/10th of 1% of our ocean's mass of about 1.5 million trillion tons.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, when the Earth was hotter when it was young, it could have had more water in it's upper atmosphere and lost more water than 0.1% per billion years.   &lt;a href=&quot;http://sciencenordic.com/earth-has-lost-quarter-its-water&quot; rel=&quot;noreferrer&quot;&gt;This estimate suggests&lt;/a&gt; that the Earth lost as much as 25% of it's water over the last 3.8 billion years based on studying deuterium ratio in 3.8 million year old rocks to water on Earth today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's also the problem of water emerging from inside the Earth.   It was recently discovered that the lower mantle is wet and there's &lt;a href=&quot;https://www.smithsonianmag.com/smart-news/there-may-be-second-massive-ocean-deep-beneath-surface-180950090/&quot; rel=&quot;noreferrer&quot;&gt;as much water deep inside the Earth as there is in the oceans&lt;/a&gt;, maybe more.   How much mantle water made it's way to the surface of the Earth during the pre-cambrian era is unknown.  &lt;a href=&quot;https://www.smithsonianmag.com/science-nature/earths-water-may-be-old-earth-itself-180957262/&quot; rel=&quot;noreferrer&quot;&gt;Some of Earth's water today likely came from inside&lt;/a&gt;, even though the heat of formation of the planet probably lost most of it, some (at least an ocean's worth) is still deep inside the Earth but much (most?) is thought to have come from comets and meteors during the late heavy bombardment.  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;So is the rise and fall of sea level derived from the geological&#xA;  record measured relative to the adjacent land, or the center of the&#xA;  earth, or what?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Speaking strictly for the geological record, it's not directly measured, but estimated by the methods discussed above, looking at geological records of old shorelines and land that was once under water and working out an estimate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sea level from the center of the Earth is mostly done for modern measurements.   You can measure sea level against the land, but land can rise and fall, or it can be measured from the center of the Earth, independent of land shifting.   I don't think that's particularly relevant to your question on geological estimates of sea level.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That probably needs some cleaning up, but it's a fun subject.   I thought I'd give it a shot.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2017-10-28T20:10:32.963" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12568" PostTypeId="2" ParentId="12562" CreationDate="2017-10-29T03:59:06.110" Score="3" Body="&lt;p&gt;&lt;strong&gt;My hypothesis on windows&lt;/strong&gt;: I asked a &lt;a href=&quot;https://earthscience.stackexchange.com/questions/12192/what-statistics-do-we-have-regarding-the-probability-of-window-breakage-by-wind&quot;&gt;similar question&lt;/a&gt; here, hoping someone more knowledgeable in structural engineering might eventually put together a more experimental answer, but so far no luck.  So with that, all I can offer is quite a lot of experience monitoring and following up on damage levels during tropical cyclones and thunderstorms in recent few years.&lt;br&gt;&#xA;And I'm starting to believe that in tropical cyclones winds may need to be somewhere up over 150 km/h (93 mph) before the first hints of direct window damage (seems to be supported by &lt;a href=&quot;https://inspectapedia.com/BestPractices/Table3-2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;this table&lt;/a&gt; from John Wiley &amp;amp; Sons Best Practices Guide to Residential Construction).  Occasionally windows will be damaged at lower speeds, if just the right debris is driven into the window... but, at least where standards are high, windows seem quite good at holding up to quite high speeds.&lt;br&gt;&#xA;However, in situations with significant gusting, such as severe convective storms, greater convergence on the leading edge (due speed change) may more increase the stress.  I tend to think that may be part of why F1 and F2 tornadoes typically do more consistently notable damage over their path than similar strength hurricane wind gusts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;In terms of general damage&lt;/strong&gt;, in the United States, we &lt;a href=&quot;https://www.weather.gov/bmx/outreach_svr&quot; rel=&quot;nofollow noreferrer&quot;&gt;consider 50 knots&lt;/a&gt; (58 mph, 93 km/h) to be the speed where the likelihood of notable damage is high enough.  Damage can occur to some very vulnerable objects (things like tarps and tents (and umbrellas!) can way well before that) at lower speeds.  But in terms of solid objects being damaged, that is the speed they selected as significant expectations.  Note that the criteria developed fairly subjectively, and wasn't resolved by some precise scientific research, but instead by members of a forecasting conference (see &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0434%281989%29004%3C0585%3ATEOSTC%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;this good explanation of the development of such speed criteria&lt;/a&gt;, particularly the end of pg 7).  But definitely by the time you get to 100 km/h, convective storms quite often start damaging notable objects like trees, fences, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Something like an antenna is quite light and moveable, so how easily it is damaged/removed should generally be based upon how sturdily installed it is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Generally 30-40 km/h shouldn't damage much unless objects have significantly weakened (perhaps by again, and impacts like weathering), are major wind foils (very light and large surface area), or have inadequate designs.  However, perhaps you actually experienced much higher gusts during the period that caused more stress on those few objects?&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2017-10-29T03:59:06.110" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12570" PostTypeId="1" AcceptedAnswerId="12571" CreationDate="2017-10-29T12:25:09.537" Score="1" ViewCount="473" Body="&lt;p&gt;As I understand it, the outer portion of the Earth can be divided into the crust and mantle on chemical grounds (separated by the Moho), or into the lithosphere and asthenosphere based on mechanical properties. The lithosphere is relatively strong and includes the crust and the upper area of the mantle. The asthenosphere below is relatively weak and deforms by diffusion creep due to the high temperatures, though the lithosphere/asthenosphere boundary is gradual (since it is temperature dependent). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, isostatic compensation for mountain ranges on continents etc. requires the mantle directly below the crust to flow. However, this is part of the lithosphere and is relatively strong - I would expect that isostatic compensation occurs for the lithosphere with respect to the asthenosphere. Is it the case that although relatively strong, this area of the lithosphere (the mantle just below the crust) is still sufficiently plastic to allow isostatic compensation of the crust?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/bHW9m.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bHW9m.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user11361" LastActivityDate="2017-10-29T13:41:52.893" Title="How can isostatic compensation of the crust be reconciled with a relatively strong upper mantle?" Tags="|plate-tectonics|mantle|isostasy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12571" PostTypeId="2" ParentId="12570" CreationDate="2017-10-29T13:41:52.893" Score="5" Body="&lt;p&gt;Because it is not the strong portion that gets displaced. The mantle just below the crust bends, just like the crust above it, together they make up the lithosphere,  It is not the thing being displaced it is the thing doing the displacing. The asthenosphere is being displaced. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your image is missing  something important. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iTPgP.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iTPgP.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gROuM.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gROuM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Images courtesy of &lt;a href=&quot;http://www.physicalgeography.net/fundamentals/10h.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.physicalgeography.net/fundamentals/10h.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2017-10-29T13:41:52.893" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12574" PostTypeId="2" ParentId="12556" CreationDate="2017-10-29T16:26:40.327" Score="2" Body="&lt;p&gt;Given that it's a quarry then at a guess the grass is growing over areas that are cut into the bedrock more deeply than the non-grassed areas, this means that there is a trench that holds a little more soil and water than the relatively bare rock outside of the cuts like a &lt;a href=&quot;https://en.wikipedia.org/wiki/Cropmark&quot; rel=&quot;nofollow noreferrer&quot;&gt;cropmark&lt;/a&gt; but smaller and more extreme.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2017-10-29T16:26:40.327" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12575" PostTypeId="2" ParentId="12556" CreationDate="2017-10-29T17:14:40.107" Score="3" Body="&lt;p&gt;&lt;strong&gt;You have two options ice segregation/frost heaving or humans screwing around&lt;/strong&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Frost heave can produce some really unusual yet regular shapes, spirals included. &#xA;Frost heave and ice segregation is when freezing ground water pushes more on larger rocks sorting them out of finer material. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Humans messing around can leave spirals intentionally (crop circles, environmental artists) or unintentionally (tethered animals, cropmarks, storing large diameter hose). Given it is a quarry it would not surprise at all if a rolled up air or suction hose was sitting there long enough to alter the sediment or vegetation and we are seeing the marks left over after it was moved. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2017-10-30T14:34:21.697" LastActivityDate="2017-10-30T14:34:21.697" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="12579" PostTypeId="1" CreationDate="2017-10-30T13:47:21.330" Score="1" ViewCount="48" Body="&lt;p&gt;Why earth revolve around the sun in oval axis. Why not in round axis? If the gravitational force of the sun is same at every place .&lt;/p&gt;&#xA;" OwnerUserId="11367" LastActivityDate="2017-10-30T13:47:21.330" Title="Earth revolve Around the sun." Tags="|earth-rotation|" AnswerCount="0" CommentCount="2" ClosedDate="2017-10-30T15:52:13.320" ContentLicense="CC BY-SA 3.0" />
  <row Id="12583" PostTypeId="2" ParentId="12561" CreationDate="2017-10-30T21:56:02.233" Score="1" Body="&lt;p&gt;From my correspondence with Dr. Hamilton, who is one of the leading researchers on forest rings (emphasis mine):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;They can be irregular (see figure below) but it is not very common. You&#xA;are right, the circularity is why we notice them and there are&#xA;probably lots that we don’t notice because they are not round.&#xA;However, the mechanism of formation that we have postulated ought to&#xA;produce circular shapes. All point-source force fields in an isotropic&#xA;medium will produce a circle if the area of influence is large enough.&#xA;We argue that the source of energy is the electrochemical potential&#xA;(redox) difference between the inside and outside of the ring; and the&#xA;force is an electrical field. The groundwater and glacial overburden&#xA;have fairly isotropic electrical conductivity (the inverse of&#xA;resistance) and therefore &lt;strong&gt;circularity is a requirement if the current&#xA;density is sufficient&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/V43hP.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/V43hP.jpg&quot; alt=&quot;various forest rings of various sizes and shapes&quot; /&gt;&lt;/a&gt;&#xA;This photo was taken near from northeastern Ontario north of Kapuskasing. The circular ring is  ~150m across.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="11353" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-10-30T21:56:02.233" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12584" PostTypeId="2" ParentId="12414" CreationDate="2017-10-31T11:19:44.820" Score="6" Body="&lt;p&gt;The geology of Lithuania is pretty complex - ice ages could have brought  nearly anything. The fossil belongs to Rugose corals - an extinct order of solitary and colonial corals that were abundant in Middle Ordovician to Late Permian seas. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For precise identification try Baltoscandia fossil database: &lt;a href=&quot;http://fossiilid.info/46&quot; rel=&quot;noreferrer&quot;&gt;http://fossiilid.info/46&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11156" LastActivityDate="2017-10-31T11:19:44.820" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12586" PostTypeId="1" CreationDate="2017-10-31T12:27:04.257" Score="5" ViewCount="163" Body="&lt;p&gt;I am a beginner to atmospheric modeling. I want to know about the change in vertical wind intensity in modeling studies. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, if I initiate a simulation,I will get the real vertical wind velocity of that place, or winds with weaker intensity calculated as per the model equations intensifying with each timestep? What are the factors which control it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am asking this because I made several setups to study a real time event and I am getting the winds with different intensity. I want to know which of them is right. if I am wrong anywhere, what could be the associated factor that caused it.&lt;/p&gt;&#xA;" OwnerUserId="11162" LastActivityDate="2018-02-02T16:29:32.457" Title="Change in vertical wind intensity in atmospheric modeling" Tags="|atmosphere-modelling|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12588" PostTypeId="1" AcceptedAnswerId="12595" CreationDate="2017-11-01T06:47:59.460" Score="8" ViewCount="761" Body="&lt;p&gt;Happily spending my holidays in the Fiji Islands, I noticed a couple of days ago that when the moon was very high in the sky (my shadow was maybe  0.5-1m long) the tide was low. That really puzzled me. How does this happen? &lt;/p&gt;&#xA;" OwnerUserId="11373" LastActivityDate="2017-11-02T14:29:48.870" Title="How come the tide is low when the moon is high in the sky" Tags="|moon|tides|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12589" PostTypeId="2" ParentId="12552" CreationDate="2017-11-01T15:30:55.177" Score="1" Body="&lt;p&gt;Most of the haze I've seen in AZ is blown dust. If it's windy and hazy, it's probably dust. There is little moisture/humidity to create haze. Pollution is also a possibility. It would have to travel from somewhere else as there isn't a lot of civilization in that area.&lt;/p&gt;&#xA;" OwnerUserId="10936" LastActivityDate="2017-11-01T15:30:55.177" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12591" PostTypeId="2" ParentId="7292" CreationDate="2017-11-01T18:28:18.590" Score="-3" Body="&lt;p&gt;Layman speaking!  I don't believe any of the above answers are correct.  If answer one is correct that the amount of lava on top is causing increasing pressure on the gas underneath then releasing the lava on top by creating a flow should theoretically reduce the pressure on the gases resulting in a smaller explosion.  Maybe drilling is not the answer due to type of magma filling the hole but certainly bunker bombs or some type of explosive could be used to control the flow and to relieve pressure?  Most of these volcanos seem to be isolated from populations and therefore are open to any type of intervention.  Why not blow the side of a volcano apart on the preferred side and see what happens?&lt;/p&gt;&#xA;" OwnerUserId="11378" LastActivityDate="2017-11-01T18:28:18.590" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12592" PostTypeId="2" ParentId="8836" CreationDate="2017-11-01T23:40:22.607" Score="1" Body="&lt;p&gt;An &lt;em&gt;isostatic model&lt;/em&gt; describes elevation differences either due to variations in density (Pratt's Isostasy model) or mass (Airy's Isostasy model). In planetary studies, variations in topography may be known, but not much else about the state of the crust. Through topography variations, variations in mass (rather: thickness) and/or density in the crust can be inferred using an isostatic model. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mJusu.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mJusu.png&quot; alt=&quot;Pratt&amp;#39;s model (left), Airy&amp;#39;s model (right) (source: stanford.edu)&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Deviatoric stress&lt;/em&gt; is, as you mentioned, the total stress minus hydrostatic stress. In this context the hydrostatic stress is supplied, in case of Enceladus by the ocean below the crust/shell (the image shows the case of the Earth, where the crust sits on the Asthenosphere). Imposing a minimum deviatoric stress constraint is a way to force the crust to be close to isostatic equilibrium (the idea is that high deviatoric stress lead to internal deformation in the crust that reduce the deviatoric stress). &lt;/p&gt;&#xA;" OwnerUserId="5748" LastActivityDate="2017-11-01T23:40:22.607" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12594" PostTypeId="2" ParentId="5174" CreationDate="2017-11-02T12:51:29.417" Score="5" Body="&lt;p&gt;I am assuming you are asking for the case of sea level being 200m higher &lt;strong&gt;and&lt;/strong&gt; in isostatic equilibrium. In that case we can make use of Airy's isostasy model: &lt;a href=&quot;https://en.wikipedia.org/wiki/Isostasy#Airy&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Isostasy#Airy&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Applied to a water column over the mantle, you have to replace $\rho_c$ with your $\rho_w$. The total increase in ocean depth is $x = b_1 + h_1$, where $h_1$ are the 200 m extra sea level and $b_1$ is the depth increase to isostasy. Using the equation given in the link: &#xA;$$&#xA;x =  \frac{h_1 \rho_w}{\rho_m - \rho_w} + h_1,&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;giving $x =$ 287 m&lt;/p&gt;&#xA;" OwnerUserId="5748" LastActivityDate="2017-11-02T12:51:29.417" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12595" PostTypeId="2" ParentId="12588" CreationDate="2017-11-02T14:29:48.870" Score="10" Body="&lt;p&gt;This is based on the overly-simplified model of tides being the result of tidal bulges. As I explained in my answer to a related question on the physics.SE sister site, &lt;a href=&quot;https://physics.stackexchange.com/questions/121830/does-earth-really-have-two-high-tide-bulges-on-opposite-sides/121858#121858&quot;&gt;those tidal bulges do not and cannot exist&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Instead, the tides are dynamic responses to the tidal forcing functions from the Moon and the Sun, with the orbits of the three bodies about one another, the Earth's rotation rate, and the geometry of the oceanic basins all playing roles in the dynamic response. For any point on the surface of the Earth's oceans, the tides can be described in terms of a composition of frequency responses to those cyclic forcing functions. See the related question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/8407/definitions-of-tidal-harmonic-constituents&quot;&gt;Definitions of tidal harmonic constituents…?&lt;/a&gt; for details.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At many places, Fiji included, the key component of the tides is the $M2$ tidal constituent, with a period of 12.42 hours. This is the principal response to the tides induced by the Moon. If Newton's equilibrium (tidal bulge) theory of tides was correct, every oceanic place on the Earth's surface would see high tide when the Moon is at zenith and nadir, and low tides when the Moon is at the horizon. Except for a few places, this is not what is observed. In Fiji, the situation is nearly reversed, as depicted by the tide chart below for Nadi on the west coast of Viti Levu, where high tides are more or less in sync with moonrise and moonset.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8cEGv.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8cEGv.png&quot; alt=&quot;Graph of predicted tide heights at Nadi Waters, Viti Levu, Fiji Islands from 1 Nov to 9 Nov, 2017&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;Source: &lt;a href=&quot;https://www.tide-forecast.com/locations/Nandi-Waters-Viti-Levu-Fiji-Islands/tides/latest&quot; rel=&quot;noreferrer&quot;&gt;https://www.tide-forecast.com/locations/Nandi-Waters-Viti-Levu-Fiji-Islands/tides/latest&lt;/a&gt;, accessed 2 November, 2017.&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Laplace's dynamic theory of the tides says that the oceans' response to each of the tidal constituents comprises a set of amphidromic systems. Each such system is centered about an amphidromic point, a place with a null response to the component in question. A wave whose amplitude increases with distance from the the amphidromic point rotates about the amphidromic point at the constituent frequency. The $M2$ tidal response is depicted below. The $M2$ amphidromic points are at the centers of the dark blue areas. The white lines emanating from the amphidromic points are cotidal lines, curves along which high tide occurs at the same time. The different colors indicate height, which again increase with distance from the governing amphidromic point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/V7Xyp.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/V7Xyp.jpg&quot; alt=&quot;The response to the tidal forcing function comprise a number of different frequencies. The component with the largest response, by more than a factor of two, is the semidiurnal lunar tide, designated as &amp;quot;M2&amp;quot; by George Darwin. This image uses colors to depict the amplitude of the M2 tidal response around the globe. Key features are the amphidromic points, places where the M2 component is zero, the cotidal lines that emanate from these amphidromic points, and the directions in which these cotidal lines rotate about the amphidromic points.&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;Source: &lt;a href=&quot;http://en.wikipedia.org/wiki/File:M2_tidal_constituent.jpg&quot; rel=&quot;noreferrer&quot;&gt;http://en.wikipedia.org/wiki/File:M2_tidal_constituent.jpg&lt;/a&gt;.&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-11-02T14:29:48.870" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12597" PostTypeId="2" ParentId="12586" CreationDate="2017-11-02T18:37:35.783" Score="1" Body="&lt;p&gt;The vertical equation of motion can vary considerably from one model to another, however, in general for a non-hydrostatic model the predominant terms are: advection, vertical pressure gradient and buoyancy. The order of importance of the previous terms depends on the phenomenon that is being modeled. The classic formulation of this equation, on a Cartesian coordinate system and without considering the effect of air humidity, reads:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ \frac{\partial w}{\partial t} = - (u\frac{\partial w}{\partial x}+v\frac{\partial w}{\partial y}+w\frac{\partial w}{\partial z})-\frac{1}{\rho}\frac{\delta p^\prime}{\delta z}-g\frac{\rho^\prime}{\rho} $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where the state variables are defined as the sums of base-state variables and the deviations from the base state as $p=\bar{p}+p^\prime$ and $\rho=\bar{\rho}+\rho^\prime$. The base state is assumed to be horizontally homogeneous, time invariant and hydrostatically balanced. Note that, in the fully compressible model the linearization with the reference atmosphere is not employed.&lt;/p&gt;&#xA;" OwnerUserId="7037" LastActivityDate="2017-11-02T18:37:35.783" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12598" PostTypeId="1" AcceptedAnswerId="12600" CreationDate="2017-11-03T00:42:22.880" Score="8" ViewCount="241" Body="&lt;p&gt;Diamonds are predominately formed in cratons and brought to the surface in kimberlite pipes.  However, it seems theoretically possible that diamonds could form at either subduction zones or from meteorite impact sites where the temperature and pressure would be suitable for diamond formation in the presence of coal. - &lt;a href=&quot;https://en.wikipedia.org/wiki/Diamond&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any evidence of diamonds being formed from coal at a subduction zone, or from a meteorite impact, and if so, where did this occur?&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastEditorUserId="6129" LastEditorDisplayName="user11318" LastEditDate="2020-05-08T06:13:06.033" LastActivityDate="2020-05-08T06:13:06.033" Title="Could diamonds be formed from coal?" Tags="|plate-tectonics|meteorite|diamond|coal|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12599" PostTypeId="1" CreationDate="2017-11-03T10:00:10.223" Score="5" ViewCount="256" Body="&lt;p&gt;I'm doing a school project on cosmic rays (using data from the HiSPARC database), and we need to be able to calculate the average temperature of the atmosphere above specific cities on a specific date to input into the Ideal Gas Equation (PV=nRT). We are trying to find an estimate for the number of molecules between the detectors and space, which is where the proton emitted breaks down into the parts which are detected, so that we can create a mathematical model which can calculate an estimate for the number of cosmic rays detected by a detector in a day. I've looked around, but nowhere tells me a way to do it, including other questions on this site. We've decided to do one effect at a time, so there may be more questions like this in the future. Can anyone help me?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Good news - thanks to those that gave answers I have values for the number of molecules. This question is answered! (Watch me for others soon: possibly clouds and such)&lt;/p&gt;&#xA;" OwnerUserId="11385" LastEditorUserId="11385" LastEditDate="2017-11-08T13:05:54.837" LastActivityDate="2017-11-08T13:05:54.837" Title="How do we calculate an average temperature for the air above a specific point from weather data?" Tags="|meteorology|atmosphere|climate|temperature|gas|" AnswerCount="0" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="12600" PostTypeId="2" ParentId="12598" CreationDate="2017-11-03T10:35:00.920" Score="8" Body="&lt;p&gt;Craters actually can be identified by formation of high-pressure materials such as diamonds or stishovites and coesites (varieties of shocked quartz). A good example of this is the Popigai crater in Russia. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pressures and temperatures at subduction zones are usually too low to form big diamonds but microdiamonds (10-80 microns) were discovered within metamorphic rocks related to continental collisions. There are five well confirmed diamond-bearing terranes, the Kokchetav massif of Kazakhstan, Dabie and Quinlin in China, the Western Gneiss Region of Norway, the Erzgebirge massif of Germany, and the Kimi complex of the Greek Rhodope (according to the paper &lt;a href=&quot;http://www.pnas.org/content/104/22/9128.long&quot; rel=&quot;noreferrer&quot;&gt;http://www.pnas.org/content/104/22/9128.long&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="11156" LastActivityDate="2017-11-03T10:35:00.920" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12601" PostTypeId="1" CreationDate="2017-11-03T10:35:22.863" Score="4" ViewCount="2957" Body="&lt;p&gt;I'm looking for a simple classification of rivers according to their width. In which size categories should I split them? This may usually be done according to catchment area but I'm more interested in the width at one spot of the river. I'm interested in the width at a given spot and point in time, not in the variability in width along the river or in different seasons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ideally this classification would make some sense (e.g. rivers smaller than x meter width are usually not used for ship traffic, rivers larger than x meter are commonly not crossed by bridges, etc.) or is commonly used in official documents (preferably in Europe).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Intuitively I would classified them according to the following but without much reasoning behind it:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;below 2m (can be jumped)&lt;/li&gt;&#xA;&lt;li&gt;3-10m (may be used for leisure water sport)&lt;/li&gt;&#xA;&lt;li&gt;11-25m (smaller commercial vessels?)&lt;/li&gt;&#xA;&lt;li&gt;26-50m (large commercial vessels?)&lt;/li&gt;&#xA;&lt;li&gt;51-100m (may still be bridged)&lt;/li&gt;&#xA;&lt;li&gt;over 100m (very large rivers, close to flowing into the sea)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="8434" LastEditorUserId="8434" LastEditDate="2019-08-22T13:02:32.967" LastActivityDate="2020-01-20T12:28:56.473" Title="Classification of rivers according to width" Tags="|rivers|" AnswerCount="3" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="12602" PostTypeId="2" ParentId="12556" CreationDate="2017-11-03T11:13:26.417" Score="4" Body="&lt;p&gt;I came across this photo from &lt;a href=&quot;http://hikingsdcounty.com/mount-calavera/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mount Calavera, San Diego County, California&lt;/a&gt;.  It is described as rock art and is also found in the floor of a quarry.  The spiral pattern, including the vegetation, is very similar to your photo.  In your photo it looks like the rocks have just been removed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HofiB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HofiB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rocks appear to affect the soil moisture available for vegetation by shading. From a study in Southwest China investigating the influence of bare rocks on soil moisture:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;•We found that bare rocks influenced the surrounding soil moisture by shading.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;•The effect degree of rocks to surrounding soil moisture correlated with its shape.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;•Soil moisture on the north side of the rocks was significantly higher than others.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;•The location at 15 cm north of the rocks was ideal site for plantation restoration.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0341816213003123&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.sciencedirect.com/science/article/pii/S0341816213003123&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it possible that rocks used to be placed in a spiral pattern in your photo that allowed the vegetation to take hold?&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastEditorDisplayName="user11318" LastEditDate="2017-11-04T00:29:35.337" LastActivityDate="2017-11-04T00:29:35.337" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12603" PostTypeId="1" AcceptedAnswerId="12647" CreationDate="2017-11-03T16:50:37.047" Score="0" ViewCount="67" Body="&lt;p&gt;How to calculate of the number of monocationic millimoles?&#xA;If I have concentrations of: $SiO_2$, $TiO_2$, $K_2O$, $MgO$, $MnO$, $Na_2O$, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can I get $Na^+$, $Mg^{2+}$, $Mn^{2+}$ ..?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is part of an intent to calculate the weathering intensity scale suggested by Meunier et al. (2013), but it is a doubt suitable to any kind of use of oxides, so post it apart from it. See a related &lt;a href=&quot;https://earthscience.stackexchange.com/q/12621/11388&quot;&gt;WIS question&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Reference:&lt;/strong&gt; Meunier, A.; Caner, L.; Hubert, F.; El Albani, A. and Prêt, D. (2013). &lt;em&gt;The weathering intensity scale (WIS): An alternative approach of the Chemical Index of Alteration (CIA)&lt;/em&gt;. American Journal of Science, 313(2), p.113-143. doi: &lt;a href=&quot;http://dx.doi.org/10.2475/02.2013.03&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.2475/02.2013.03&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11388" LastEditorUserId="725" LastEditDate="2017-11-11T08:23:35.867" LastActivityDate="2017-11-11T08:30:09.317" Title="calculation monocationic elements" Tags="|geochemistry|atmospheric-chemistry|biogeochemistry|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12605" PostTypeId="1" CreationDate="2017-11-04T04:04:14.017" Score="3" ViewCount="2055" Body="&lt;p&gt;I have a question that I am confused about. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a mineral (say limestone) was added to a groundwater system, say like an aquifer and is completely dissolved in solution, can it ever be a solid again without evaporation happening? My thinking is if there are other sources of calcium to the system then that might promote oversaturation of the solution and so the mineral calcite would precipitate out again. Am I right? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks.&lt;/p&gt;&#xA;" OwnerUserId="11394" LastActivityDate="2018-03-12T14:47:56.897" Title="Dissolved minerals" Tags="|precipitation|minerals|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12607" PostTypeId="1" AcceptedAnswerId="12620" CreationDate="2017-11-04T19:09:16.570" Score="6" ViewCount="212" Body="&lt;p&gt;According to the &lt;a href=&quot;http://www.new-madrid.mo.us/index.aspx?nid=132&quot; rel=&quot;noreferrer&quot;&gt;New Madrid, Missouri&lt;/a&gt; web site, during the 1811-1812 earthquakes there were reports of lights coming from the ground due to quartz crystals being squeezed.  They call this phenomena “seismoluminescence.”  There are also &lt;a href=&quot;https://www.youtube.com/watch?v=7aQpni-FHyQ&quot; rel=&quot;noreferrer&quot;&gt;videos&lt;/a&gt; online taken during the 2017 Chiapas, Mexico earthquake showing strange lights in the sky.  Lights have been reported associated with numerous other earthquakes throughout history.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any research that has been done to either prove or disprove that these reported lights are actually being caused by the earthquake, and if so how are the lights created? &lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2019-05-17T10:17:08.147" Title="Lights associated with earthquakes?" Tags="|earthquakes|seismology|geomagnetism|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12608" PostTypeId="1" CreationDate="2017-11-04T23:04:10.580" Score="1" ViewCount="80" Body="&lt;p&gt;I found this rock along with a few other very similar ones. I found it on an island in Croatia.I was wondering if anyone could tell me the name of the rock.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/AqYwp.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AqYwp.jpg&quot; alt=&quot;It appears to be a mineral of some sort&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11396" LastActivityDate="2017-11-04T23:04:10.580" Title="I was wondering if anyone could help me identify this rock" Tags="|geology|rocks|" AnswerCount="0" CommentCount="2" ClosedDate="2019-09-07T00:44:26.600" ContentLicense="CC BY-SA 3.0" />
  <row Id="12612" PostTypeId="1" AcceptedAnswerId="12613" CreationDate="2017-11-06T00:12:05.637" Score="1" ViewCount="306" Body="&lt;p&gt;I am writing a somewhat realistic space game, and instead of the commercial 3 or 4 commodities model, I am making my players suffer with all 118 elements. I have gathered the data needed to create templates for several types of planets, but when it comes to a template for extraction rates I am finding it surprisingly difficult to come up with some statistics I thought everybody loved, and despite the dozens of pages, I cannot find a site that would give me the total number of tons of minerals extracted from Earth per year. Any working number would do, if you can make a guess.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I read 55 billion tons per year somewhere, but that hinted as including organic production as well. The issue is specially sensitive in my case because what is extracted is taken out of the planet... &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since I am here :D , I am also looking for an estimate of: (1) number of mines in the world (2) number of people working (anyhow) in them (3) Number of factories in the world. Though some of these might better suit some other subject, I'd appreciate if you can point me at some direction. Thanks in advance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT Only to clarify something about the 118 element model I was asked,as to the mining and usability of some elements:&#xA;We humans haven't yet discovered all the possibilities, but then Tc didn't have a chance to have its possibilities fully explored because we didn't find any during most of our existence :) However, once you find the technology to perpetuate Tc in a Bose-Einstein state, it is noted that the very properties that make it unusable now makes it the best energy dispersor in existence (important in shield technology). As to mining, yes, on Earth, and Earth minerals, S is a result of Cu mining, but on the gaseous planet Pioi there is no Copper, but plenty of free floating Sulphur, CRUCIAL in terraforming barren planets :) and all mines mine all there is in a body by abundance, not separate mines for each element, or that would be a micromanagement nightmare! I mean, if a settlement has, say, 10000 mines, the output is proportional to abundances of this moon/planet settled (which takes into consideration multiple mining). That is actually why I need the numbers in question!&#xA;(Incidentally I just remembered that an Rb surface is a great catalyst for alpha particle cycling during the first phases of ignition in star construction :P (It is 'realistic', but still as a sci-fi game)&lt;/p&gt;&#xA;" OwnerUserId="11401" LastEditorUserId="11401" LastEditDate="2017-11-06T13:58:21.353" LastActivityDate="2017-11-06T13:58:21.353" Title="What is the total weight of mineral extractions from Earth per year?" Tags="|mining|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12613" PostTypeId="2" ParentId="12612" CreationDate="2017-11-06T01:59:59.140" Score="1" Body="&lt;p&gt;This may give you some useful information. You can download the World Mineral Production (2011-2015) produced by the British Geological Survey at this &lt;a href=&quot;https://www.bgs.ac.uk/mineralsuk/statistics/worldStatistics.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt;. This publication has data for approximately 70 different commodities by country and world totals (tonnes).&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2017-11-06T01:59:59.140" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12614" PostTypeId="2" ParentId="12605" CreationDate="2017-11-06T04:09:28.363" Score="4" Body="&lt;p&gt;There are several processes that can cause a mineral to precipitate from solution. You mention one which is adding elements to the solution This could occur in a number of ways. For example, aragonite is a form of calcium carbonate with a higher solubility at low temperatures than the mineral calcite that makes up limestone. So it can dissolve and cause calcite to precipitate. Ions adsorbed on the surface of minerals like clay minerals can exchange with ions in solution changing the concentrations and causing precipitation. Two different compositions of water can mix to cause minerals to precipitate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Changing temperature can also make minerals precipitate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Changing the pH or oxidation state affects the solubility of various minerals. Increasing the pH will cause precipitation of calcite from a saturated solution. One way this can occur is to degas carbon dioxide from the water. That's what causes the formation of stalactites in caves.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-11-06T04:09:28.363" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12615" PostTypeId="1" CreationDate="2017-11-05T22:15:06.927" Score="1" ViewCount="175" Body="&lt;p&gt;The Earth's atmosphere rotates along with the Earth. At what altitude does the atmosphere cease to rotate along with the Earth? Is it the altitude at which Gravity has no effect? Forgive me if it is a dumb question. I don't know too much about science.&lt;/p&gt;&#xA;" OwnerDisplayName="Good ole boy" LastEditorUserId="5594" LastEditDate="2017-11-06T11:04:26.880" LastActivityDate="2017-11-06T11:04:26.880" Title="Earths rotation" Tags="|atmosphere|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12616" PostTypeId="2" ParentId="12615" CreationDate="2017-11-06T01:06:24.533" Score="6" Body="&lt;p&gt;Upper atmospheric air is coupled by friction to lower atmospheric air.  So it will on the average spin near the same rotational rate as lower atmospheric air.  The friction coupling to lower atmospheric air is greater than to the higher and thinner air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gravity always has some effect, it just gets less as one is further from the gravitational source. Think tides of the oceans getting manipulated by the sun and also the moon, both which are a good distance away, but still have some (quite measurable) effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since air has mass, there is some inertia, however the air at higher altitudes is coupled via friction to lower atmospheric air, so any inertial forces are effectively coupled to the daily rotation of the earth, not to some &quot;stopped&quot; movement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So bottom line, the air rotates around the earth daily, and is coupled via friction and other properties to the air below it, which is coupled more strongly to the surface of the earth. Think of a bunch of people walking around a round swimming pool, with the water spinning with them&lt;/p&gt;&#xA;" OwnerUserId="11408" OwnerDisplayName="mongo" LastActivityDate="2017-11-06T01:06:24.533" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12618" PostTypeId="2" ParentId="12612" CreationDate="2017-11-06T09:50:57.300" Score="0" Body="&lt;p&gt;Not a direct answer, but a comment on this:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;commercial 3 or 4 commodities model, I am making my players suffer with all 118 elements&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Why? What for?&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;118 elements have been discovered. Many of them are not stable for more than a fraction of a second, are highly radioactive, and are completely useless. Tc, Pm, most of the actinides and post-actinides.&lt;/li&gt;&#xA;&lt;li&gt;Many elements are mined together with other elements, and not on their own. Cd and In are by products of Zn. La, Ce, Pr and Nd are usually mined together. Same for Ti and V. You don't need a mine for each and every one.&lt;/li&gt;&#xA;&lt;li&gt;Some elements are kind of useless. Rb. Hardly any uses for it. S is a by product of Cu mining, and there's no use for so much. When you mine Pr and Nd, you end up with lots of (almost) worthless La and Ce. What about Th? Hardly any market for it.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;If you're writing a realistic space game, make it somewhat realistic. Don't just throw in all elements in the periodic table because that's not realistic.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-11-06T09:50:57.300" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12619" PostTypeId="1" CreationDate="2017-11-06T10:51:20.103" Score="3" ViewCount="39" Body="&lt;p&gt;I am interested in sampling soil solution at different depths on Andean soils. I have found that Passive-capillary samplers have been extensively used to sample soil water, however I was not able to find a specific design methodology. Does anyone has knowledge about this technique or can recommend some bibliography?&lt;/p&gt;&#xA;" OwnerUserId="5820" LastActivityDate="2017-11-06T10:51:20.103" Title="Passive capillary wick samplers" Tags="|soil-moisture|soil-science|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12620" PostTypeId="2" ParentId="12607" CreationDate="2017-11-06T11:37:27.713" Score="3" Body="&lt;p&gt;I am not too much into the subject, but it is a curious phenomenon indeed.&#xA;There is a recent publication in Scientific Reports (Enomoto et al., 2017) where a group of scientists performed some lab experiments and reported:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;CO2 gases passing through the newly created fracture surface of the rock were electrified to generate pressure-impressed current/electric dipoles, which could induce a magnetic field following Biot-Savart’s law, decrease the atmospheric electric field and generate dielectric-barrier discharge lightning affected by the coupling effect between the seismic and meteorological activities&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;If you want to read the full paper you can search it with this reference: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Enomoto, Y., Yamabe, T., &amp;amp; Okumura, N. (2017). &lt;em&gt;Causal mechanisms of seismo-EM phenomena during the 1965–1967 Matsushiro earthquake swarm&lt;/em&gt;. Scientific Reports, 7. doi: &lt;a href=&quot;http://dx.doi.org/10.1038/srep44774&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.1038/srep44774&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is open access.&lt;/p&gt;&#xA;" OwnerUserId="11407" LastEditorUserId="5594" LastEditDate="2017-11-06T13:24:00.143" LastActivityDate="2017-11-06T13:24:00.143" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12622" PostTypeId="5" CreationDate="2017-11-06T15:31:40.493" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2017-11-06T15:31:40.493" LastActivityDate="2017-11-06T15:31:40.493" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12623" PostTypeId="4" CreationDate="2017-11-06T15:31:40.493" Score="0" Body="This is a special tag that is designed to be used only by the system for questions that have had all of their other tags removed. Do not add this tag to existing questions, it is reserved for use by the system to identify posts with no valid tags." OwnerUserId="2958" LastEditorUserId="2958" LastEditDate="2017-11-06T23:27:17.940" LastActivityDate="2017-11-06T23:27:17.940" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12624" PostTypeId="2" ParentId="12207" CreationDate="2017-11-07T00:35:16.243" Score="2" Body="&lt;p&gt;It may be beneficial to look at what we know about agriculture during the &lt;a href=&quot;https://en.wikipedia.org/wiki/Medieval_Warm_Period&quot; rel=&quot;nofollow noreferrer&quot;&gt;Medieval Warm Period&lt;/a&gt; to start to get an answer to this question.  During this time period, c950-c1250, there was an &lt;a href=&quot;http://study.com/academy/lesson/the-medieval-warm-period-and-new-agricultural-technologies.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;agricultural revolution in Europe&lt;/a&gt; and there is some evidence of &lt;a href=&quot;http://sciencenordic.com/vikings-grew-barley-greenland&quot; rel=&quot;nofollow noreferrer&quot;&gt;barley being produced in Greenland&lt;/a&gt; by the Vikings. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WbSFJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WbSFJ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Granted there may still be some debate about how warm the Medieval Warm Period was, especially in comparison to what many are expecting will happen in the future, but it does seem like there is a good deal of evidence that during the Medieval Period there was a good deal more agriculture occuring at higher latitudes.  This doesn't necessarily answer whether or not the arctic areas will be suitable for large scale agriculture in the future, but if history is a guide, addition northern lattitudes with suitable soils will become more productive.&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2017-11-07T00:35:16.243" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12630" PostTypeId="1" CreationDate="2017-11-08T20:14:10.117" Score="1" ViewCount="37" Body="&lt;p&gt;I planning to start my own medical/culinary growing farm somewhere in the not too far future. I'm on a training at the moment on this subject (I'll get a mid-level exam paper about it that I can use to work in this field). Luckily the literature in my native language (Hungarian) is pretty good but I would happily read something international on this subject to widen my views.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is that is there any literature on this subject? I'm interested in industrial growing only (like what machinery to use, how to grow herbs on hectares etc) but mainly what I get is how to grow a few herbs in your garden.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks.&lt;/p&gt;&#xA;" OwnerUserId="11429" LastActivityDate="2017-11-08T20:14:10.117" Title="Books about industrial medical and culinary herb growing" Tags="|agriculture|" AnswerCount="0" CommentCount="2" ClosedDate="2017-11-09T08:19:19.867" ContentLicense="CC BY-SA 3.0" />
  <row Id="12631" PostTypeId="2" ParentId="12603" CreationDate="2017-11-08T21:49:33.927" Score="0" Body="&lt;p&gt;Rock chemical analysis can be expressed as oxides, and I think this is what you are asking about. Since there are two moles of monoatomic cation per mole of oxide, multiply the molar oxide concentration by 2.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-11-08T21:49:33.927" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12632" PostTypeId="1" CreationDate="2017-11-09T00:10:40.170" Score="5" ViewCount="1830" Body="&lt;p&gt;Earlier this year 'river-effect' snow was reported in the Quad Cities (Western Illinois) along the Mississippi River.  Per the &lt;a href=&quot;http://wqad.com/2017/01/27/river-effect-snow-occurring-near-the-quad-cities-this-morning/&quot; rel=&quot;noreferrer&quot;&gt;local news report&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;According to Andy Ervin, a Meteorologist with the National Weather&#xA;  Service, &quot;You need an environment supporting flurries to get&#xA;  saturation for the enhanced snow showers. Air gets channeled between&#xA;  the bluffs and resides over the water at least 45 minutes to pick up&#xA;  the enhanced instability. Thus, you won't see this if winds increase,&#xA;  change direction, or we lose the cold air aloft.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I have only found two other short articles of 'river-effect' snow which occurred along the &lt;a href=&quot;http://cimss.ssec.wisc.edu/goes/blog/archives/17174&quot; rel=&quot;noreferrer&quot;&gt;Missouri River&lt;/a&gt; in South Dakota and over the &lt;a href=&quot;http://www.wxforum.net/index.php?topic=21284.0&quot; rel=&quot;noreferrer&quot;&gt;Ohio River&lt;/a&gt; in Cincinnati.  Both of these events occurred in 2014.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is if there are any other reports of this phenomena world wide and has there been any research published?&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2019-12-09T22:31:22.400" Title="'River-effect' snow" Tags="|meteorology|snow|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12635" PostTypeId="1" CreationDate="2017-11-09T12:02:01.197" Score="1" ViewCount="193" Body="&lt;p&gt;What is seismic stretch in geophysical method ?&lt;/p&gt;&#xA;" OwnerUserId="11439" LastActivityDate="2018-11-18T17:33:57.707" Title="What is seismic stretch in geophysical method?" Tags="|geophysics|seismic|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="12636" PostTypeId="1" CreationDate="2017-11-09T13:16:02.707" Score="1" ViewCount="90" Body="&lt;p&gt;I read about it somewhere in a paper.  Why is kriging not gridless if I can krig points in space? Whats is the big difference from RBF?&lt;/p&gt;&#xA;" OwnerUserId="11366" LastEditorUserId="6298" LastEditDate="2018-01-14T21:43:49.473" LastActivityDate="2018-01-14T21:43:49.473" Title="Why RBF is gridless and kriging is not?" Tags="|geology|numerical-modelling|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12637" PostTypeId="1" AcceptedAnswerId="12638" CreationDate="2017-11-09T14:24:14.287" Score="9" ViewCount="1929" Body="&lt;p&gt;I'm terribly frustrated with the way that climate change has been debated in Europe. I live in the Netherlands and members  of one of the biggest parties here, the Party for Freedom (PVV), frequently deny climate change and use terms like &amp;quot;climate hysteria&amp;quot; and &amp;quot;the religion of climate change&amp;quot;. While I'm no climate scientist, geologist or meteorologist I do worry about the climate, simply for the reason that the large majority of experts does! I know that the exact percentage of consensus has been debated, &lt;a href=&quot;https://www.bloomberg.com/view/articles/2017-06-15/97-percent-consensus-on-climate-change-it-s-complicated&quot; rel=&quot;noreferrer&quot;&gt;consensus according to Bloomberg&lt;/a&gt;, &lt;a href=&quot;https://www.theguardian.com/environment/climate-consensus-97-per-cent/2017/may/03/is-the-climate-consensus-97-999-or-is-plate-tectonics-a-hoax&quot; rel=&quot;noreferrer&quot;&gt;consensus according to the Guardian explaining their methods&lt;/a&gt;, but it's pretty hard to argue that there is no consensus in general..&lt;/p&gt;&#xA;&lt;p&gt;However, one of the arguments that climate change skeptics use is that the 97% (or whatever percentage you feel is right) consensus among climate scientists  is misleading. Misleading, because most climate scientists are meteorologists, and meteorologists tend to have a different view on climate, compared to geologists. The skeptics say that the consensus among geologists is way lower. From what I understand (again I'm  no geologist), is that some geologists support an alternative theory to explain climate change that involves plate tectonics.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What is in fact the consensus among geologists about climate change being caused by humans?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Remark:&lt;/strong&gt;&#xA;Please excuse me for the elaborate introduction to my question. I don't want to make this a concealed political statement, but it is something that's bothering me. Why would you, as a layman, choose to believe the small minority on such an important issue? I definitely don't think we should ignore or silence climate change skeptics, obviously accepted scientific beliefs have been proven wrong in the past, but it does feel rather strange to me that so many politicians are of an opinion that is backed by only 3% of the world's leading scientists.&lt;/p&gt;&#xA;&lt;p&gt;Thanks in advance!&lt;/p&gt;&#xA;" OwnerUserId="11440" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2021-10-19T07:49:32.447" Title="What is the consensus among geologists about climate change being caused by humans?" Tags="|meteorology|geology|climate-change|climate|plate-tectonics|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="12638" PostTypeId="2" ParentId="12637" CreationDate="2017-11-09T15:53:16.773" Score="19" Body="&lt;p&gt;First, a correction. Most climate scientists are climatologists rather than meteorologists. Climatology and meteorology, while related, are quite distinct sciences. Meteorologists and climatologists don't see eye to eye. The consensus amongst meteorologists regarding climate change is not nearly as strong as it is amongst climatologists. &lt;a href=&quot;http://www.slate.com/articles/health_and_science/science/2016/04/meteorologists_and_regular_people_still_aren_t_sure_humans_cause_climate.html&quot; rel=&quot;noreferrer&quot;&gt;Many meteorologists still doubt human-driven climate change&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One key issue is that meteorologists know that predicting the weather beyond a week or two is impossible thanks to the butterfly effect. This knowledge makes them rather skeptical of claims by climatologists regarding what will happen in 50 to 100 years. Climate is not weather, of course. That weather is not predictable beyond a week or two does not mean that climate is not predictable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same cannot be said regarding geologists. They take a long view of things, arguably longer even than that taken by climatologists. The consensus amongst geologists is quite strong. The Geology Society (British) issued a strong statement regarding climate change in 2010 (&lt;a href=&quot;https://www.geolsoc.org.uk/~/media/shared/documents/policy/Statements/Climate%20Change%20Statement%20final%20%20%20new%20format.pdf?la=en&quot; rel=&quot;noreferrer&quot;&gt;Climate change: evidence from the geological record&lt;/a&gt;) and made this even stronger with &lt;a href=&quot;https://www.geolsoc.org.uk/~/media/shared/documents/policy/Statements/Climate%20Change%20Statement%20Addendum%202013%20Final.pdf?la=en&quot; rel=&quot;noreferrer&quot;&gt;an adddendum&lt;/a&gt; in 2013. The Geological Society of America conducted informal surveys of its members at annual meetings in 2009 and 2011 (&lt;a href=&quot;http://www.geosociety.org/gsatoday/archive/23/1/article/i1052-5173-23-1-51.htm&quot; rel=&quot;noreferrer&quot;&gt;GSA members on climate change: Where, what, and ways forward?&lt;/a&gt;) The consensus was quite strong. Of the 181 members who were surveyed, only two &quot;clearly stated they do not believe anything will occur because climate change is not happening&quot;. This is in line with the 97% consensus amongst climatologists.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-11-09T15:53:16.773" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12641" PostTypeId="1" CreationDate="2017-11-10T13:20:13.953" Score="3" ViewCount="108" Body="&lt;h3&gt;Background&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;I'm analysing the metallic elements in $PM_{2.5}$ to identify their possible anthropogenic sources for the study area. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A total of 19 metallic elements were investigated including dust-derived elements such as $Al, Ca, Mg$ and pollution-derived elements such as $Pb, Cu, Cd, Zn$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To better investigate the characteristics of different elements, their temporal variation (daily samples, collecting once for 6 days at an industrial city in China) during the whole year was analyzed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found out the burning of fireworks for celebrating China Spring Festival presented significant contribution to related elements, such as:   &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$Al, Mg$: they are utilized for the fuels of gunpowder. &lt;/li&gt;&#xA;&lt;li&gt;$K$: the chemical compounds of $K$$ (KClO_4, KClO_3, KNO_3$) are usually utilized for the oxidant of gunpowder.     &lt;/li&gt;&#xA;&lt;li&gt;$Cu, Sr, Ba$ : used for generating lighting in different color.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Since the emission of firework burning were centered on the festival night, the influence should be short. We collect the aerosol samples and analyzed their species for the festival, one day after festival and two days after festival.  &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Observation results&lt;/h3&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Most of related elements presented the significant levels on the festivity and decreased sharply in the next day (~ 100 times). &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;However, I found three heavy metals with adverse health effects ($Pb, Cd, As$) had increases in concentration levels after the festival. Their concentration levels recovered to their normal level after 3 days.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h3&gt;My thought&lt;/h3&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Most of the related elements recovered to their normal levels in one day, the accumulation of $Pb, Cd, As$ should not be blamed on meteorological conditions; &lt;/li&gt;&#xA;&lt;li&gt;There might not be other important sources leading to the continuous increases of $Pb, Cd, As$ in 3 days, &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Therefore, I though the accumulation of high concentration levels in 3 days should be attributed to firework burning,&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This finding would be valuable since a short-time emissions event resulted in a relative long-time exposure to high concentrations if my inference is correct. &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;My question&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Does the atmospheric lifetime differs for specific elements?  I assumed that the elements $Pb, Cd, As$ presented a long atmospheric lifetime with less deposition? &#xA;I still felt confused by the phenomenon. Any advice or comments on my question would be hugely appreciated! &lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="2470" LastEditDate="2017-11-10T15:26:26.843" LastActivityDate="2017-11-11T07:14:23.127" Title="What control the atmospheric lifetime of different metals in aerosols?" Tags="|atmosphere|air-pollution|atmospheric-chemistry|environmental-protection|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12642" PostTypeId="1" CreationDate="2017-11-10T14:43:34.830" Score="3" ViewCount="286" Body="&lt;p&gt;These two cities are facing the worst &lt;code&gt;smog&lt;/code&gt; in Asia and I think in the world and people of these cities have no choice other than to wear masks when going outside. So what &lt;strong&gt;Advance technology that can be used by these two state government so that smog can be reduced to a minimum or can be eliminated&lt;/strong&gt;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;these 2 counties can't avoid smog due to large no. of factories and farmer burning residual so what Technology that can be used to reduce/eliminate smog.&lt;/p&gt;&#xA;" OwnerUserId="11443" LastEditorUserId="6467" LastEditDate="2018-09-23T23:52:38.993" LastActivityDate="2019-08-17T20:56:49.320" Title="How Can Smog in Metropolitan Cities like Delhi &amp; Beijing Be Reduced?" Tags="|atmosphere|climate-change|air-pollution|air-quality|geoengineering|" AnswerCount="5" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="12643" PostTypeId="2" ParentId="12642" CreationDate="2017-11-10T15:19:16.240" Score="5" Body="&lt;p&gt;The first thing to do is to stop putting pollution in the air, particularly very small particulate matter that are produced by combustion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the Beijing Olympic Games of 2008, the Chinese government forced the polluting plants and factories in the vicinity of Beijing and nearby areas to stop operating for weeks prior to the games and during the games to ensure the air in Beijing was clear and had minimal pollution during the duration of the games. The measure was successful.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Burning wood, animal dung, coal, petroleum products (particularly diesel and heavy oil) produce soot and other small particulate matter which leads to poor air quality and smog.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is an easy solution that results in clean air. The difficulty with this is that it is detrimental to the economy in the short term. For a longer term solution, energy sources need to be changed to ones that do not cause air pollution.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-11-10T15:19:16.240" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12644" PostTypeId="2" ParentId="10593" CreationDate="2017-11-11T01:22:54.647" Score="1" Body="&lt;p&gt;Neither displacement nor acceleration; most seismometers measure velocity. If you want displacement, you integrate the output over time, and if you want acceleration, you differentiate the output over time. Check the datasheet for the instrument you are interested in. For example, the &lt;a href=&quot;https://www.guralp.com/documents/DAS-030-0001.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Guralp 3T datasheet&lt;/a&gt; says that it outputs 1500V m/s, so for each meter per second of ground velocity the output increases by 1500V. (It also says it only outputs from +20V to -20V, so this means ground velocities greater than 20/1500 = 0.013 m/s will be &quot;off the chart&quot; i.e. saturate the instrument).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Actually, the voltage output from a seismometer is not exactly proportional to displacement, velocity, OR acceleration. The actual output is the input displacement convolved with the impulse response of the seismometer. It's just that the impulse response is designed such that it will have an approximately linear response to ground velocity within the corner frequencies. In the 3T datasheet we were looking at, they say it's within -3 dB of linear as long as it's measuring ground that's not oscillating faster than 50Hz or slower than 0.0083Hz for one version of the instrument.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Measuring displacement directly is known as geodesy (as opposed to seismometry) and the tools used for those measurements include GPS, lidar, and radar.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To measure acceleration (strong motion), as Jay says, you can use an accelerometer. Or, &lt;a href=&quot;https://pubs.usgs.gov/dds/dds-058/Ch_M.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;precariously balanced rocks&lt;/a&gt; for the palaeo case!&lt;/p&gt;&#xA;" OwnerUserId="63" LastEditorUserId="63" LastEditDate="2017-11-12T00:58:52.273" LastActivityDate="2017-11-12T00:58:52.273" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12645" PostTypeId="1" AcceptedAnswerId="12678" CreationDate="2017-11-11T05:55:22.610" Score="2" ViewCount="373" Body="&lt;p&gt;If we consider gnomonic projection, what are projections of curves with constant latitude. For example, we know that great circles are projected to straight lines. So, equator should be projected on a straight line, right? What about curves with constant latitude in general?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: We use North pole as a tangent point.&lt;/p&gt;&#xA;" OwnerUserId="11446" LastEditorUserId="11446" LastEditDate="2017-11-14T03:13:42.743" LastActivityDate="2017-11-15T11:07:17.850" Title="Gnomonic projection of a curves with constant latitude" Tags="|geography|mapping|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12646" PostTypeId="2" ParentId="12641" CreationDate="2017-11-11T07:14:23.127" Score="3" Body="&lt;p&gt;You could say that metals and aerosols reside in the atmosphere but I'm struggling to call that &quot;atmospheric lifetime&quot;, which I've only heard in reference to gases.  The residence time of particulate matter is mostly a function of meteorology (e.g. PBL height, wind speed) and deposition (e.g. raining, settling velocity).  You've observed some metals that had a longer residence time.  I can think of two reasons for that:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Unique reactivity with other atmospheric components will change the mass and deposition velocity of particles.  Metals that do not react well in the atmosphere may not grow as quickly and therefore settle more slowly.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Specific metals may be used more prevalently in fireworks that obtain high altitude, such that the metal emissions are injected further up into the atmosphere and subjected to more atmospheric mixing and therefore longer settling times.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;You might find &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3366381/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article by Licudine et al., (2012)&lt;/a&gt; of interest, which discusses monitoring of metals on New Years in Hawaii.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-11-11T07:14:23.127" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12647" PostTypeId="2" ParentId="12603" CreationDate="2017-11-11T08:30:09.317" Score="2" Body="&lt;p&gt;Oxygen is always divalent negative. An oxide has to be charge balanced, meaning the total has to be zero.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Therefore, some like CaO means you have Ca&lt;sup&gt;2+&lt;/sup&gt;O&lt;sup&gt;2-&lt;/sup&gt;. &lt;/li&gt;&#xA;&lt;li&gt;Something like SiO&lt;sub&gt;2&lt;/sub&gt; is going to be Si&lt;sup&gt;4+&lt;/sup&gt;2O&lt;sup&gt;2-&lt;/sup&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Something like Na&lt;sub&gt;2&lt;/sub&gt;O is going to be 2Na&lt;sup&gt;+&lt;/sup&gt;O&lt;sup&gt;2-&lt;/sup&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;As you can see, the charges all sum to zero, given that oxygen is negative two.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's work out an example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You have 1 moles of each: K&lt;sub&gt;2&lt;/sub&gt;O, MgO, and ZrO&lt;sub&gt;2&lt;/sub&gt;. You will have one mole of Mg&lt;sup&gt;2+&lt;/sup&gt;, one mole of Zr&lt;sup&gt;4+&lt;/sup&gt;, and two moles of K&lt;sup&gt;+&lt;/sup&gt;.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-11-11T08:30:09.317" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12648" PostTypeId="2" ParentId="12642" CreationDate="2017-11-11T08:38:47.307" Score="2" Body="&lt;p&gt;What advanced method?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Stop burning fossil fuels. Run vehicles on electricity. Produce electricity using solar/wind/nuclear methods. Develop new methods. Sell methods to other countries. Profit!&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-11-11T08:38:47.307" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12649" PostTypeId="1" CreationDate="2017-11-11T18:57:36.590" Score="2" ViewCount="928" Body="&lt;p&gt;Its a big number, difficult to estimate I assume. But is there a peer reviewed estimation (at current conditions) of the volume of daily or annual increase of water? &lt;/p&gt;&#xA;" OwnerUserId="11356" LastEditorUserId="11908" LastEditDate="2019-03-14T00:44:43.240" LastActivityDate="2019-03-14T00:44:43.240" Title="Estimated volume, daily or annually, of sea level rise due to melting ice?" Tags="|climate-change|glaciology|sea-level|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12650" PostTypeId="2" ParentId="12632" CreationDate="2017-11-11T22:40:00.387" Score="3" Body="&lt;p&gt;This effect seems to be similar to the &quot;lake effect snow&quot;. The main difference between those two effects is the body of water involved hence the difference in name.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In rather general terms: The cold air picks up moist air above the relatively warm body of water (being a river, lake or the sea). To achieve a significant amount of snow fall the air mass has to be a fairly long time above the water (&quot;at leats 45 minutes&quot;, stated in the question). This is the main reason why &quot;river effect snow&quot; is not too common. &quot;Lake effect snow&quot; (describing again basically the same process) is more common, since the conditions (airmass crossing a lake (or the sea) for at least 45 minutes) are more often met.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake-effect_snow&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; lake effect snow occurs on the whole of the Northern hemisphere (where temperatures during winter get cold enough for snow fall) in proximity to sufficiently large bodies of water. Especially the coasts of the North Sea, the Baltic Sea, the Black Sea and the Sea of Japan. Apparently Istanbul is very prone to lake effect snow and experiences it basically each winter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quite some research on the lake effect snow was done during the past decades:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0493(1966)094%3C0495:MSOALE%3E2.3.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Peace and Sykes, 1966&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0469(1982)039%3C1521:ASDRSO%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kelly, 1981&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0434(1987)002%3C0310:OFOLES%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Niziol, 1987&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0434(1995)010%3C0061:WWFTTE%3E2.0.CO;2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Niziol et al., 1994&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The publications by Niziol (and collaborators) focus on the forecasting.&lt;/p&gt;&#xA;" OwnerUserId="10752" LastActivityDate="2017-11-11T22:40:00.387" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12651" PostTypeId="1" AcceptedAnswerId="12652" CreationDate="2017-11-12T18:41:54.643" Score="2" ViewCount="171" Body="&lt;p&gt;I've been reading about volcanic eruptions on wikipedia, and I've found that very big eruptions cause the earth's temperature to drop by a small fraction of a degrees Celsius due to the ash it releases which blocks the sunlight from heating the earth (particularly the 1991 Pinatubo eruption that caused global cooling by 0.5 Celsius).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does this mean if we trigger massive eruptions around the globe, will we be able to combat global warming?&lt;/p&gt;&#xA;" OwnerUserId="11451" LastActivityDate="2017-11-12T22:03:03.663" Title="Can Volcanic Eruptions Help Combat Global Warming in the Long Run?" Tags="|climate-change|volcanology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12652" PostTypeId="2" ParentId="12651" CreationDate="2017-11-12T22:03:03.663" Score="3" Body="&lt;p&gt;The subject you are looking for is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_engineering&quot; rel=&quot;nofollow noreferrer&quot;&gt;climate engineering&lt;/a&gt;. In general, changing atmospheric composition in order to achieve a cooling effect that counteracts climate change is conceivable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whether triggering volcanic eruptions is the most feasible approach (or possible at all) is of course a completely different issue. From my understanding of volcanoes, you would really need massive eruptions with large plume-heights to achieve long-term impact.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also note that we would need to sustain the resulting atmospheric change over a long time. And the side effects of releasing large amounts of pollutants into the atmosphere need to be considered too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For some more aspects read &lt;a href=&quot;https://earthscience.stackexchange.com/a/9807/681&quot;&gt;this answer&lt;/a&gt; to a related question.&lt;/p&gt;&#xA;" OwnerUserId="681" LastActivityDate="2017-11-12T22:03:03.663" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12653" PostTypeId="1" AcceptedAnswerId="12688" CreationDate="2017-11-12T22:47:28.063" Score="4" ViewCount="82" Body="&lt;p&gt;The &lt;a href=&quot;https://www.britannica.com/event/Deepwater-Horizon-oil-spill-of-2010&quot; rel=&quot;noreferrer&quot;&gt;Deep Water Horizon oil spill&lt;/a&gt; occurred in 2010 and is known as the largest marine oil spill ever. I heard on the radio the other day, from a not so reliable source, that contaminant levels have dropped in the 90% range since then due to naturally occurring organisms that feed off the hydrocarbons.  Is there any good current research out there now that shows what current concentrations are compared to what they were after the spill? &lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2017-11-15T17:33:28.443" Title="Current contaminant levels from Deep Water Horizon oil spill?" Tags="|ocean|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12654" PostTypeId="1" CreationDate="2017-11-12T23:31:45.770" Score="1" ViewCount="55" Body="&lt;p&gt;I'm currently a Computer Science undergraduate at Georgia Tech. I have ~3.5 GPA, and I want to become a data scientist for the NOAA or a similar organization concerning the acidification of the oceans. I want to find &lt;em&gt;solutions&lt;/em&gt; for this problem instead of just finding out more of what's going on. I plan on doing a PhD in Computer Science and Engineering after that with the engineering focus being related to the environment. &lt;/p&gt;&#xA;" OwnerUserId="11454" LastActivityDate="2017-11-12T23:31:45.770" Title="Should I get my master's in Environmental Science or Environmental Engineering given a Computer Science background?" Tags="|data-analysis|ocean-models|education|" AnswerCount="0" CommentCount="1" ClosedDate="2017-11-13T17:15:46.240" ContentLicense="CC BY-SA 3.0" />
  <row Id="12655" PostTypeId="2" ParentId="12215" CreationDate="2017-11-12T23:54:16.167" Score="1" Body="&lt;p&gt;&quot;In short, what makes nuclear weapons so damn good at being destructive, compared to everything that nature seems to have in its arsenal short of the death of the Sun itself, despite seemingly the much greater raw power in terms of energy of the latter?&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;It was answered in the source itself:&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&quot;The climatic effects of the use of nuclear weapons&#xA;depend on the amount of smoke they would generate,&#xA;and this depends on the targets. Nuclear targeting&#xA;plans call for not only cities to be targeted, but also&#xA;industrial facilities such as oil refineries and wells.&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;Turning to what nature has in its arsenal, there have been several mass extinctions on the Earth caused not by nuclear weapons but volcanism in its extreme form. &#xA;Here's an &lt;a href=&quot;https://arstechnica.com/science/2017/11/when-will-the-earth-try-to-kill-us-again/&quot; rel=&quot;nofollow noreferrer&quot;&gt;article&lt;/a&gt; that identifies far more deadly factors coming along with volcanic phenomena bigger than supervolcanos called Large Igneous Province; not only energy alone matters in determining what is deadlier.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;So what makes nuclear winter so extreme and destructive?&#xA;Targeting nuclear weapons at mega-cities and industrial facilities where lots of toxic material are piled up.&lt;/p&gt;&#xA;" OwnerUserId="11453" LastEditorUserId="11453" LastEditDate="2017-11-15T21:29:58.583" LastActivityDate="2017-11-15T21:29:58.583" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12657" PostTypeId="2" ParentId="7145" CreationDate="2017-11-13T08:35:26.407" Score="2" Body="&lt;p&gt;Rain is slightly cooler than near-surface temperatures because it condenses at higher altitudes where the air is colder. Thus rain tends to reduce the temperature difference between the surface and higher altitudes. This temperature difference is the free-energy or exergy source that ultimately drives convective weather systems and storms, and is expended or diminished by their operation. Usually the temperature of rain is only a few degrees cooler than that of ambient air by the time it falls to the surface. An extreme example is hail --- because of the large size and rapid fall of hailstones they can reach the surface still frozen even in midsummer. By contrast, freezing rain is often a different phenomenon. Freezing rain often results when rain originating in a warm air mass aloft falls through a subfreezing air mass near the surface, as typically occurs ahead of an advancing warm front.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2017-11-13T08:35:26.407" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12658" PostTypeId="1" CreationDate="2017-11-13T11:56:26.377" Score="2" ViewCount="459" Body="&lt;p&gt;Aside from the earthquake triggering a quick clay landslide, is there anything else notable?&lt;/p&gt;&#xA;" OwnerUserId="11459" LastActivityDate="2017-11-14T11:27:54.470" Title="Does the Composition of Rock Near the Epicenter Affect the Effects of an Earthquake?" Tags="|earthquakes|bedrock|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12659" PostTypeId="1" AcceptedAnswerId="12661" CreationDate="2017-11-13T14:40:23.697" Score="2" ViewCount="331" Body="&lt;p&gt;Death in a closed environment due to lack of O2 is actually not that bad:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=kUfF2MTnqAw&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=kUfF2MTnqAw&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And as far as I know as we are cutting down our life saving woods and jungles less $O_2$ is being produced and more $CO_2$ is not converted back to $O_2$.&#xA;Greenpeace and others tell us how bad this fact is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But: If it continues like this, is it possible for humanity to extinct itself because we run out of $O_2$ and breath in too much $CO_2$?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wouldn't it be much nicer than like burning to death if the $O_2$ would disappear?&lt;/p&gt;&#xA;" OwnerUserId="11460" LastEditorUserId="11460" LastEditDate="2018-03-18T17:28:48.240" LastActivityDate="2018-03-18T17:28:48.240" Title="Could earth run out of O2?" Tags="|co2|oxygen|" AnswerCount="1" CommentCount="1" ClosedDate="2017-11-14T22:59:42.380" ContentLicense="CC BY-SA 3.0" />
  <row Id="12660" PostTypeId="1" CreationDate="2017-11-13T14:59:14.433" Score="1" ViewCount="125" Body="&lt;p&gt;In the following questions I am wondering how large woody debris and/or submerged trees enhance river or lake environments.  Also I am wondering how they are detrimental to humans. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that large woody debris and submerged trees are commonly found in rivers and lakes. They may be present by a result of flooding, logging, bank erosion, forest fires, beavers and many other causes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not sure how they would enhance river or lake environments.  Clearly beavers could use them to build dams but how is this good? Is there any other ways they benefit?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, how are they detrimental to humans?  Might they potentially hurt the ecosystem present in the water, which in turn may hurt humans if they are using the ecosystem for resources? &lt;/p&gt;&#xA;" OwnerUserId="11462" LastEditorUserId="6298" LastEditDate="2017-11-14T01:53:40.983" LastActivityDate="2017-11-14T04:28:06.177" Title="Results of large woody debris in river/lake" Tags="|rivers|lakes|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="12661" PostTypeId="2" ParentId="12659" CreationDate="2017-11-13T15:50:34.613" Score="8" Body="&lt;p&gt;No, that will not happen. There is just too much oxygen in the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Over 20% of our atmosphere is oxygen. &#xA;Only about 0.04 % of our atmosphere is CO&lt;sub&gt;2&lt;/sub&gt;, so too much CO&lt;sub&gt;2&lt;/sub&gt; would kill us much sooner than the lack of oxygen. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you reduced the oxygen concentration in the atmosphere from 20.8% to 19.8%, you wouldn't even feel the difference. If you reduced it to 15 %, you would still &lt;a href=&quot;http://www.geography.hunter.cuny.edu/tbw/wc.notes/1.atmosphere/oxygen_and_human_requirements.htm&quot; rel=&quot;noreferrer&quot;&gt;survive it&lt;/a&gt;. You could even survive 10 % for short time periods.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, let's see what would happen if you added CO&lt;sub&gt;2&lt;/sub&gt; as a replacement for the oxygen you removed: at 1%, you would feel extreme dizziness. At 5% you would lose consciousness and die.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the real danger in CO&lt;sub&gt;2&lt;/sub&gt; lies elsewhere. Even an increase from our current 0.040 % to 0.045 % could cause a lot of damage to the climate, and an increase above 0.055 % could be &lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_change_mitigation_scenarios&quot; rel=&quot;noreferrer&quot;&gt;disastrous&lt;/a&gt;. Unless you are locked in a small room, the reason why the increase of CO&lt;sub&gt;2&lt;/sub&gt; and decrease of oxygen will be dangerous won't be because you wouldn't be able to breathe. Changes significantly smaller than those required to make breathing difficult, would be enough to wreck the ecosystem, cause drought, desertification, starvation, and economic collapse.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also note, that trees are very important for the water cycle, as a habitat for many species, and for preventing soil erosion, but they play an insignificant role in producing oxygen. Most of our oxygen is produced by &lt;a href=&quot;http://www.ecology.com/2011/09/12/important-organism/&quot; rel=&quot;noreferrer&quot;&gt;algae&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2442" LastEditorUserId="2442" LastEditDate="2017-11-13T18:47:06.237" LastActivityDate="2017-11-13T18:47:06.237" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12662" PostTypeId="2" ParentId="12649" CreationDate="2017-11-13T16:32:08.077" Score="2" Body="&lt;p&gt;I don't know if this helps, but since you have no response yet perhaps I can offer some thoughts.Your question is problematic due to the fact that volume itself is variable according to the temperature of the water. If you look at the &lt;a href=&quot;https://climate.nasa.gov/vital-signs/sea-level/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nasa site&lt;/a&gt; concerning sea level change:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Sea level rise is caused primarily by two factors related to global&#xA;  warming: the added water from melting ice sheets and glaciers and the&#xA;  expansion of sea water as it warms.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(some nice graphics here showing change amounts)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This expansion due to warming literally changes the volume of the water, adding to the sea level rise. So glacial melt may be measured or estimated, but the change in sea level caused by this volume of water is variable; over time it will change temperature and expand. But this isn't straightforward either. &lt;a href=&quot;https://sealevel.nasa.gov/understanding-sea-level/causes/overview&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nasa again&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Thermal expansion of seawater can be the product of regional&#xA;  phenomena, such as El Niño, the periodic warming of the eastern&#xA;  tropical Pacific. But some of these regional cycles so far show no&#xA;  direct link to long-term global climate change—despite, at times,&#xA;  independently exerting a powerful short-term influence on global&#xA;  climate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So bottom line is that it is easier to measure the amount of change, then to calculate direct figures concerning how much actual water was involved in causing that change. Hope this helped.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Update:&lt;/strong&gt; There is some specific data on &lt;a href=&quot;https://sealevel.nasa.gov/understanding-sea-level/causes/drivers-of-change&quot; rel=&quot;nofollow noreferrer&quot;&gt;another page&lt;/a&gt; of the Nasa site concerning the volume of water being generated by the melt of the Greenland Ice Sheet:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The estimated total loss is in the range of more than 200 to more than&#xA;  300 gigatons per year (1 gigaton is approximately 264 billion gallons&#xA;  of water. Melting 365 gigatons of ice would add 1 millimeter to global&#xA;  sea level; there are 25.4 millimeters in an inch).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This does give you some approximations in gallons per year of one of the main contributors to the sea level rise.&lt;/p&gt;&#xA;" OwnerUserId="6057" LastEditorUserId="6057" LastEditDate="2017-11-14T14:28:00.987" LastActivityDate="2017-11-14T14:28:00.987" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12664" PostTypeId="1" CreationDate="2017-11-13T22:44:56.997" Score="4" ViewCount="95" Body="&lt;p&gt;A quick Google scholar search indicates that 243,000 papers have the words &quot;Tropical Cyclone.&quot; While scientific literature is considered valuable (predatory publishing and pseudo-scientific journals excluded), some papers are more important than others. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are some of the most important, or most cited, papers within hurricane research?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In anticipation of one criticism of the question: &#xA;&lt;a href=&quot;https://earthscience.meta.stackexchange.com/questions/1441/should-we-allow-requests-for-references&quot;&gt;Should we allow requests for references?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2017-11-16T22:21:39.473" LastActivityDate="2017-11-16T22:21:39.473" Title="What are the most notable papers in tropical cyclone research?" Tags="|tropical-cyclone|research|literature-request|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12665" PostTypeId="1" AcceptedAnswerId="12667" CreationDate="2017-11-13T23:28:57.933" Score="1" ViewCount="305" Body="&lt;p&gt;For tropical cyclones we have carefully tracked every instance of them, and naming them as soon as they have reached a certain intensity... flying aircraft in to measure conditions... compiling databases... creating models... and putting great emphasis on improving predictions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it seems like for extratropical cyclones we do less. People only recently started to name extratropical cyclones... there doesn't seem to be a database of them... and they're just not portrayed as being as concerning when you hear about them on the news, even though they can have comparable wind speeds and minimum pressure to many tropical cyclones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is there this difference?&lt;/p&gt;&#xA;" OwnerUserId="11465" LastEditorUserId="6298" LastEditDate="2017-11-14T01:24:20.447" LastActivityDate="2017-11-14T01:24:20.447" Title="Why do tropical cyclones get more attention than extratropical cyclones?" Tags="|weather-forecasting|tropical-cyclone|severe-weather|mesoscale-meteorology|cyclone|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12666" PostTypeId="2" ParentId="12660" CreationDate="2017-11-13T23:54:52.207" Score="1" Body="&lt;p&gt;Depending on the fauna within the rivers and lakes, submerged trees can be like reefs in oceans. They provide protection for fish and other fauna and they can also act as nurseries for certain types of fish.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Submerged trees can sometimes be snags in waterways which increases the difficulty in navigating waterways, particularly for larger boats.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-11-13T23:54:52.207" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12667" PostTypeId="2" ParentId="12665" CreationDate="2017-11-14T00:42:38.000" Score="2" Body="&lt;p&gt;Extratropical cyclones are relatively well understood. They often follow the &lt;a href=&quot;https://www.srh.noaa.gov/jetstream/synoptic/cyclone.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Norwegian Cyclone model&lt;/a&gt;, which was developed in the 1910's and 1920's. Because of their spatial extent, extratropical cyclones are often less intense than their tropical counterparts. Since they are so much larger and live longer over land, it is easy to get data about an extratropical cyclone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tropical cyclones, on the other hand, have faster winds and affect people in a more dramatic fashion. If an extratropical cyclone is announced in winter, a grocery store may run out of bread. If a tropical cyclone is announced, there may not be a clerk available to restock the shelves. Tropical cyclones often don't live very long over land and are smaller, so it is hard to get data about them. Because they are smaller and the wind speed change over distance is so much greater in extratropical cyclones than tropical cyclones, errors in the forecast tend to have more of a dramatic effect on tropical cyclones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To summarize:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Extratropical cyclones are often less intense.&lt;/li&gt;&#xA;&lt;li&gt;We have an abundance of data on extratropical cyclones.&lt;/li&gt;&#xA;&lt;li&gt;The theory behind the development of extratropical cyclones is longstanding and generally well established.&lt;/li&gt;&#xA;&lt;li&gt;Tropical cyclones are much more dramatic and concentrated.&lt;/li&gt;&#xA;&lt;li&gt;Forecast errors impact tropical cyclones more severely than extratropical cyclones (i.e. less predictable).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-11-14T00:42:38.000" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12668" PostTypeId="2" ParentId="12660" CreationDate="2017-11-14T04:28:06.177" Score="1" Body="&lt;p&gt;Ecosystem benefits of submerged trees include providing growth locations and nutrients for algae, phytoplankton, molusks, and other organisms. They can provide, not only protection for fauna, but shading for refuge from heat. They can increase eddies and areas of low flow that can be beneficial for fish and other fauna. Some species take advantage of pools formed behind downed trees in streams. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;They can increase sedimentation by trapping sediments or decreasing flow and this can have a negative impact on species that require a gravel stream bed. They can increase flooding which may have positive or negative impacts on people and the ecosystem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Snags in waterways are an issue for large boats, restricting access or causing damage in collisions, as mentioned in another answer. But they can also be deadly to small boats like kayaks and canoes. The water flows through the limbs of downed trees and the surprisingly strong hydraulic pressure can trap boaters underwater in these &quot;strainers&quot;. This can happen with stream current or tidal flow.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-11-14T04:28:06.177" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12669" PostTypeId="2" ParentId="12649" CreationDate="2017-11-14T04:41:02.063" Score="1" Body="&lt;p&gt;&lt;a href=&quot;https://earthobservatory.nasa.gov/Features/OceanCooling/page5.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA graph&lt;/a&gt;:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/STKxr.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/STKxr.gif&quot; alt=&quot;http://www.bitsofscience.org/wordpress-3.0.1/wordpress/images/2016/08/sea_level_rise-thermal-expansion-nasa.gif&quot;&gt;&lt;/a&gt;&#xA;You can find a number of articles with searches like this: &lt;a href=&quot;https://www.google.ca/search?q=&amp;quot;sea+level+rise&amp;quot;++melting+ice+expansion&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;sea level rise&quot;  melting ice expansion&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2017-11-14T17:15:07.530" LastActivityDate="2017-11-14T17:15:07.530" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12670" PostTypeId="2" ParentId="4439" CreationDate="2017-11-14T07:54:24.057" Score="0" Body="&lt;p&gt;By Bernoulli's Theorem neglecting friction a fluid of density D initially at rest flowing from higher pressure P to lower pressure P mimus delta P can attain a speed of SQRT[2(delta P)/D]. In the case of hurricanes D decreases as air spirals inwards towards lower pressure, but it is sufficiently accurate to take D as the average value of the density. Allowing typical losses for friction, for stationary vortex-type storms such as hurricanes, tornadoes, waterspouts, and dust devils, approximately, maximum wind speed MWS in mph = 100 SQRT(delta P in inches of mercury), where delta P is the drop is sea-level barometric pressure from the periphery to the eye. If the vortex is moving, its velocity of motion V should be added on its right side if its winds circulate counterclockwise and on its left side if they circulate clockwise.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastEditorUserId="8382" LastEditDate="2017-11-16T02:48:29.997" LastActivityDate="2017-11-16T02:48:29.997" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12671" PostTypeId="2" ParentId="12658" CreationDate="2017-11-14T11:27:54.470" Score="1" Body="&lt;p&gt;The soil and rock type are one factor that determines the amplification of the shaking.  In general, the softer the underlying material is the greater the shaking.  This table, from the USGS, presents the velocities of 5 soil types in the San Francisco Bay area and their shear velocities.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Soil type A   Vs &gt; 1500 m/sec Includes unweathered intrusive igneous&#xA;  rock. Occurs infrequently in the bay area. We consider it with type B&#xA;  (both A and B are represented by the color blue on the map). Soil&#xA;  types A and B do not contribute greatly to shaking amplification.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Soil type B   1500 m/sec &gt; Vs &gt; 750 m/sec Includes volcanics, most&#xA;  Mesozoic bedrock, and some Franciscan bedrock. (Mesozoic rocks are&#xA;  between 245 and 64 million years old. The Franciscan Complex is a&#xA;  Mesozoic unit that is common in the Bay Area.)&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Soil Type C   750 m/sec &gt; Vs &gt; 350 m/sec  Includes some Quaternary (less&#xA;  than 1.8 million years old) sands, sandstones and mudstones, some&#xA;  Upper Tertiary (1.8 to 24 million years old) sandstones, mudstones and&#xA;  limestone, some Lower Tertiary (24 to 64 million years old) mudstones&#xA;  and sandstones, and Franciscan melange and serpentinite.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Soil Type D   350 m/sec &gt; Vs &gt; 200 m/sec  Includes some Quaternary muds,&#xA;  sands, gravels, silts and mud. Significant amplification of shaking by&#xA;  these soils is generally expected.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Soil Type E   200 m/sec &gt; Vs  Includes water-saturated mud and artificial&#xA;  fill. The strongest amplification of shaking due is expected for this&#xA;  soil type.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The slower the shear wave velocity, the greater the shaking.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://earthquake.usgs.gov/hazards/urban/sfbay/soiltype/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earthquake.usgs.gov/hazards/urban/sfbay/soiltype/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, the composition of the rock that the seismic waves are travelling through is a major factor in determining the speed of the waves.  Two rock properties that determine the speed of the waves are reflection and refraction:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reflection&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qgrJ2.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qgrJ2.gif&quot; alt=&quot;Reflection&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;When a wave encounters a change in material properties (seismic&#xA;  velocities and or density) its energy is split into reflected and&#xA;  refracted waves.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Refraction&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3VmY6.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3VmY6.gif&quot; alt=&quot;Refraction&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://eqseis.geosc.psu.edu/~cammon/HTML/Classes/IntroQuakes/Notes/waves_and_interior.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://eqseis.geosc.psu.edu/~cammon/HTML/Classes/IntroQuakes/Notes/waves_and_interior.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are many factors involved in determining the magnitude of an earthquake with underlying sediments and rock being one of the major factors.  This is not an exhaustive list of all those factors but hopefully it points you in the right direction for an answer to your question.  &lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2017-11-14T11:27:54.470" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12673" PostTypeId="1" CreationDate="2017-11-14T14:16:04.440" Score="2" ViewCount="305" Body="&lt;p&gt;I'm working on a project in Rajasthan, India involving modelling water supply and demand in a catchment. For this, I am working with WEAP which has modules for estimating groundwater recharge using a simple bucket model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This model needs daily temperature and reference (potential) evapotranspiration values.&#xA;The reference evapotranspiration is calculated according to the modified Penman-Monteith equation as described in the &lt;a href=&quot;https://www.kimberly.uidaho.edu/water/fao56/fao56.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;FAO56-Paper&lt;/a&gt;.&#xA;As part of the project, I'd like to use climate models. One with a sufficient resolution is the &lt;a href=&quot;https://www.klima.tu-berlin.de/index.php?show=forschung_asien_tibet_har&amp;amp;lan=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;HAR&lt;/a&gt; model, which has values for potential evapotranspiration. Is there a way to get from potential evapotranspiration to the reference evapotranspiration?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: I am not sure whether the model Potential Evapotranspiration values implicitly contain information about the surface, or if they are a spatially comparable, independent of the surface. &#xA;Since I am modeling the catchment disaggregated by landuse types with a uniform climate, I need a value that is independent of the surface properties and can be transferred to the landuse types via the surface coefficients as described in the FAO paper.&lt;/p&gt;&#xA;" OwnerUserId="11466" LastEditorUserId="-1" LastEditDate="2017-11-14T15:07:15.627" LastActivityDate="2017-11-21T20:56:19.967" Title="Derive Reference Potential Evapotranspiration from Potential Evapotranspiration" Tags="|meteorology|hydrology|climate-models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12674" PostTypeId="1" CreationDate="2017-11-14T14:44:10.350" Score="2" ViewCount="594" Body="&lt;p&gt;I've been trying to collect resource data about Australia for a few years. Some good reference sites are &lt;a href=&quot;http://australiaminerals.gov.au/&quot; rel=&quot;nofollow noreferrer&quot;&gt;AustraliaMinerals.gov.au&lt;/a&gt; and &lt;a href=&quot;http://www.australianminesatlas.gov.au&quot; rel=&quot;nofollow noreferrer&quot;&gt;AustralianMinesAtlas.gov.au&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Australia seems to be pretty rich in minerals, including iron, copper, nickel, gold, titanium, uranium, and I think lithium and Rare-Earth elements too. &lt;strong&gt;But one thing I have never found is chromium.&lt;/strong&gt; Chrome is essential in the steel industry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I'd like to know why. What geological features does Australia lack that make it lacking in chrome? Or do geologists believe that there's a realistic chance that a good chrome deposit is hidden somewhere? And where could that be?&lt;/p&gt;&#xA;" OwnerUserId="2733" LastActivityDate="2017-11-15T01:14:28.443" Title="Why does Australia have no chrome?" Tags="|geology|mineralogy|minerals|resources|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12675" PostTypeId="2" ParentId="12674" CreationDate="2017-11-14T17:23:59.243" Score="0" Body="&lt;p&gt;It does have chrome , but : 1- It has not been found. or 2- The Cr content is not high enough to be considered an ore. Or 3- The total amount at a location is not sufficient to build the infrastructure to extract it. Not likely  4- the political situation is not stable , eg, there are copper deposits in Africa up to 4% Cu that are not extracted while Cu deposits of 0.05 % are commercial in the US.  &lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2017-11-14T17:23:59.243" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12676" PostTypeId="2" ParentId="2410" CreationDate="2017-11-14T18:58:58.810" Score="-1" Body="&lt;p&gt;One cause of glaciation on earth is dust from volcanic activities ie you have heard the term volcanic or nuclear winter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During glaciation continental plates with a mile or two of ice piled upon them increase vastly in weight and actually sink.  When we see a rock we see a hard stone object, but that rock within the earth under a vast amount of pressure is not &quot;rock&quot; solid, it is more the like peanut butter, it is soft and pliable.  This is how continental plates are able to sink under the weight of a mile or two thick sheet of ice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not only do the continental plates have weight pushing down on this peanut butter like rock beneath us, the oceans also have weight and they as well push the plates beneath them down into this peanut butter like stone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During glacial maximums ocean levels drop by as much as 400 feet, so what is currently 400 feet underwater was dry land during the last glacial maximum.  This loss of 400 feet of water across all the oceans of the earth greatly reduces weight upon the ocean floors.  That same water is turned to snow and collects as ice on the continental plates this adds that same weight now to the continental plates.  So the oceanic plates raise while the continental plates drop.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During interglacial periods you get a lightening of continental plates and the oceanic plates become heavier with the return of high ocean water levels ie global sea level rise such as we are experiencing currently.  Continental plates rise and oceanic plates drop.  This reaction is not immediate, again if you imagine peanut butter if you put a board over several inches of peanut butter and add weight to the board it takes some time for the peanut butter to squish out the sides, the same with the continental plates and the soft stone they sit atop of.  It takes thousands of years for the continental plates to rebound to their original height.  During this rebounding of the continental plates and the dropping of the oceanic plates volcanic activity slowly starts to increase.  Eventually it is only a matter of time before you get another great volcanic eruption due the plate movement that produces a great deal of ash in the atmosphere, this continues again and again with increased levels of volcanic activity.  This ash reflects light back into space before it is able to reach and warm the surface, thereby reducing average global temperatures. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is certainly not the only mechanism that controls glacial maximum and interglacial periods but it does work in concert with the afore written answers to your question.  The normal condition for our planet during human existence is glacial maximum conditions, what we are experiencing now an &quot;interglacial&quot; period exists only about 20% of the time somewhere on average of about 20k years per 100k years.  This is the second interglacial period in the last 100k years.  You have go back to 120k to 130k years for the next previous interglacial period.&lt;/p&gt;&#xA;" OwnerUserId="11468" LastActivityDate="2017-11-14T18:58:58.810" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12677" PostTypeId="2" ParentId="12674" CreationDate="2017-11-15T01:01:57.163" Score="4" Body="&lt;p&gt;There has only been one chromium mine in Australia - the &lt;a href=&quot;http://mininglink.com.au/site/coobina&quot; rel=&quot;nofollow noreferrer&quot;&gt;Coobina&lt;/a&gt; mine, in the Pilbara region of Western Australia. It is located 80 km south east Newman (23 deg 29' 31&quot; south, 120 deg 16' 32&quot; east). The resource at Coobina is 1.5 Mt @ 29.4% Cr.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The ore deposit was discovered in 1924 and was once worked under the names of Jimblebah and Murramunda. It was mined as a series of small open cuts for several decades with most of the pits being less than 70 metres deep.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The deposit is associated with an ultramafic unit.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Chromite deposits in this rock occurs as massive chromite with up to 150 lenses having been mapped so far. The largest around 340 metres long and 6 metres wide.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.mindat.org/loc-219441.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chromium clinochlore&lt;/a&gt; is mined at Coobina/Jimblebah.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other deposits of chromite occur at &lt;a href=&quot;http://minerals.statedevelopment.sa.gov.au/invest/mineral_commodities/chromite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mount Christie, Tomkinson Ranges and Wingella Hills, in South Australia&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mount Christie is within the Gawler craton and Tomkinson Ranges and Wingella Hills are within the Musgrave block.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At Moount Christie,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The best intersection was 1.5 m at 9.8% Cr2O3. Microprobe analysis showed the chromite to contain ~48% Cr2O3 and 30% FeO, which may only be suitable as chemical-grade chromite.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Chromite has been identified within Mesoproterozoic Giles Complex rocks in the far northwest of the State. It occurs as rare veins up to 10 mm thick within layers of pyroxenite in the Tomkinson Ranges (Coats, 1956) and as grains in ultrabasic rocks of the Wingelinna Hills intrusions. A representative sample gave an assay of 16.9% Cr2O3.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.ga.gov.au/provexplorer/provinceDetails.do?eno=39804&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geoscience Australia&lt;/a&gt; has very little information about Coobina.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some more information from &lt;a href=&quot;http://econgeol.geoscienceworld.org/content/108/2/337&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geoscience World&lt;/a&gt; and &lt;a href=&quot;https://www.researchgate.net/publication/275620777_Deformed_Chromitite_Layers_in_the_Coobina_Intrusion_Pilbara_Craton_Western_Australia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Research Gate&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-11-15T01:01:57.163" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12678" PostTypeId="2" ParentId="12645" CreationDate="2017-11-15T01:03:04.820" Score="3" Body="&lt;h2&gt;Circles!&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Well, some of them, anyway.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can plot any &lt;a href=&quot;http://www.progonos.com/furuti/MapProj/Normal/ProjAz/projAz.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;azimuthal projection&lt;/a&gt; in polar coordinates, where the radius is a function of the angular distance from the center point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So where two points' angular distances are the same, their radii are the same, and the projection of any locus of constant angular distance from the center point is a circle, if it appears at all.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since you said that the tangent point is a pole, that means that parallels (lines of constant latitude) are those lines of constant angular distance. Ergo, Northern Hemisphere parallels appear as circles. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/8/81/Usgs_map_gnomic.PNG&quot; alt=&quot;Different graticules for various centerings of the Gnomonic projection&quot;&gt;&#xA;(Wikimedia Commons)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the Gnomonic projection can show only a single hemisphere, the Equator and parallels in the Southern hemisphere can't appear at all -- they would be an infinite distance from the center point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The polar orientation of the projection even takes away  complications resulting from the earth's not being a perfect sphere -- the radius formula changes a little, but the equal results from the same input remain.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2017-11-15T11:07:17.850" LastActivityDate="2017-11-15T11:07:17.850" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12679" PostTypeId="2" ParentId="12674" CreationDate="2017-11-15T01:07:40.487" Score="4" Body="&lt;p&gt;Australia does have chromium ores.  This table from the World Mineral Production Report (2011-2015) published by the &lt;a href=&quot;http://www.bgs.ac.uk/mineralsuk/statistics/worldStatistics.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;British Geologic Survey&lt;/a&gt; shows that chromium ores were mined in Australia as recently as 2013.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CKHAC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CKHAC.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastEditorDisplayName="user11318" LastEditDate="2017-11-15T01:14:28.443" LastActivityDate="2017-11-15T01:14:28.443" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12680" PostTypeId="2" ParentId="12642" CreationDate="2017-11-15T04:12:58.300" Score="1" Body="&lt;p&gt;There is no technology that makes air pollution disappear on such a large scale after it has already been emitted into the atmosphere.  However, timing burns so that air quality impacts are minimized is possible if meteorology is considered.  If there is a meteorological forecast that mixing heights will be low, a &quot;burn ban&quot; should be put in place.  If mixing heights are expected to be high and/or the wind direction is expected to blow away from the city, then burning could be allowed with minimized effects on air quality in the densely populated areas.  This type of practice is used in the USA in various states.  &lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-11-15T04:12:58.300" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12681" PostTypeId="1" AcceptedAnswerId="12682" CreationDate="2017-11-15T05:25:24.773" Score="4" ViewCount="98" Body="&lt;p&gt;I saw the catchy Phys.org news title &lt;a href=&quot;https://phys.org/news/2017-11-artificially-cooling-planet-risky-strategy.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Artificially cooling planet '&lt;strong&gt;risky strategy&lt;/strong&gt;,' new research shows&lt;/a&gt; and then looked at the &lt;em&gt;open access article&lt;/em&gt;, in Nature Communications (14-Nov-2017 online) &lt;a href=&quot;https://www.nature.com/articles/s41467-017-01606-0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Impacts of hemispheric solar geoengineering on tropical cyclone frequency&lt;/a&gt;, Jones et al. doi:10.1038/s41467-017-01606-0&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Abstract:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Solar geoengineering refers to a range of proposed methods for counteracting global warming by artificially reducing sunlight at Earth’s surface. The most widely known solar geoengineering proposal is stratospheric aerosol injection (SAI), which has impacts analogous to those from volcanic eruptions. Observations following major volcanic eruptions indicate that aerosol enhancements confined to a single hemisphere effectively modulate North Atlantic tropical cyclone (TC) activity in the following years. Here we investigate the effects of both single-hemisphere and global SAI scenarios on North Atlantic TC activity using the HadGEM2-ES general circulation model and various TC identification methods. We show that a robust result from all of the methods is that SAI applied to the southern hemisphere would enhance TC frequency relative to a global SAI application, and vice versa for SAI in the northern hemisphere. &lt;strong&gt;Our results reemphasise concerns regarding regional geoengineering and should motivate policymakers to regulate large-scale unilateral geoengineering deployments&lt;/strong&gt;. (emphasis added)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The paper seems to warn against &lt;em&gt;single-hemisphere&lt;/em&gt; solar geoengineering. Was that the plan to begin with, and nobody until now thought that cooling one hemisphere but not the other one might be problematic?&lt;/p&gt;&#xA;&lt;p&gt;Or is this paper simply stating something more common-sense, for example &amp;quot;if you do it wrong, it won't work right&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Was there in fact any plan for &lt;strong&gt;unilateral geoengineering deployments&lt;/strong&gt; before this was published, or is there a bit of grandstanding along with the science?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-02-05T05:33:52.360" Title="Were there any plans or proposals for &quot;unilateral geoengineering deployments&quot; before this paper was publsihed?" Tags="|atmosphere|climate-change|geoengineering|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12682" PostTypeId="2" ParentId="12681" CreationDate="2017-11-15T07:42:15.547" Score="8" Body="&lt;p&gt;I think the introduction of the paper itself covers this adequately:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;… a growing number of studies have investigated regional SG application scenarios, which could prove preferential to a global application by restricting the geospatial magnitude of the climate response or by being used to target specific climate changes&lt;sup&gt;8,9,10,11&lt;/sup&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The cited references are:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ol start=&quot;8&quot;&gt;&#xA;&lt;li&gt;&lt;p&gt;Robock, A., Oman, L. &amp;amp; Stenchikov, G. L. Regional climate responses to geoengineering with Tropical and Arctic SO2 injections. J. Geophys. Res. 113, D16101 (2008).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;MacCracken, M. C. On the possible use of geoengineering to moderate specific climate change impacts. Environ. Res. Lett. 4, 045107,  &lt;a href=&quot;https://doi.org/10.1088/1748-9326/4/4/045107&quot; rel=&quot;noreferrer&quot;&gt;https://doi.org/10.1088/1748-9326/4/4/045107&lt;/a&gt;   (2009).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;MacMartin, D. G., Keith, D. W., Kravitz, B. &amp;amp; Caldeira, K. Management of trade-offs in geoengineering through optimal choice of non-uniform radiative forcing. Nat. Clim. Change 3, 365–368 (2013).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Haywood, J. M., Jones, A., Bellouin, N. &amp;amp; Stephenson, D. Asymmetric forcing from stratospheric aerosol impacts Sahelian rainfall. Nat. Clim. Change 3, 660–665 (2013).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Of those, [9] seems the most obviously relevant, although it covers more techniques than just SAI. One particularly relevant passage from [9] reads:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;… materials lofted this high and staying&#xA;in the atmosphere for extended periods tend to spread out to&#xA;cover the globe. As a result, both their climatic influences&#xA;and any unintended side effects (e.g., increased scattering&#xA;of incoming solar radiation that diminishes the efficiency of&#xA;direct-beam solar energy technologies) tend to be global in&#xA;extent.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Since [9] is focused on discussing regionally-targeted geoengineering techniques, the presumed global spread of SAI is here being mentioned mainly as a potential disadvantage.&lt;/p&gt;&#xA;&lt;p&gt;I think Jones et al. are actually raising two concerns with their work:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Unilaterally deployed SIA targeted at a particular region could have negative side-effects. This is the topic most relevant to your question. As the references show, there were indeed plans for this, at least in the sense that it had been discussed in the literature for some years. I don't know of any state drawing up concrete plans for SIA stations yet, but it's probably a good idea to raise these concerns before the policy train gets rolling.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;SIA might be deployed at a single site as a &lt;em&gt;globally&lt;/em&gt; targeted SG technique, with the assumption (as seen in [9]) that it doesn't matter where you do it because the aerosols will spread evenly over the globe in any case. Jones et al. show that this will not necessarily happen.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="94" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-11-15T10:03:26.737" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12683" PostTypeId="1" CreationDate="2017-11-15T10:41:04.767" Score="1" ViewCount="106" Body="&lt;p&gt;I been accessing daily historical NOAA GSOD data through Google BigQuery. I am interested in long term time series of snow, precipitation, and to a lesser extent temperature for areas around the Volga Basin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Initially, I have looked at weather station 274530, which is near Gorodets in Russia, and have noticed that there are oddities in the data. The snow depth changes substantially over a short period of time. This doesn't seem to be a system recognized 'error' or 'lack of reading' code, which according to the documentation and data is usually a 999.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8H5nk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8H5nk.png&quot; alt=&quot;Some of the oddities in the snow depth data&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Excuse my red squiggles).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not sure how to deal with this data, it isn't &quot;missing&quot;. I do not have a good understanding of the underlying physical system but I suspect that snow level doesn't change suddenly like the above graph, only to revert back to a similar level the next day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How should I interpret this data, and what actions should I take to 'clean' it (if any)? Ultimately I would like to have confidence in this data so that I can use it for modelling purposes across hundreds of weather stations.&lt;/p&gt;&#xA;" OwnerUserId="11470" LastActivityDate="2017-11-15T10:41:04.767" Title="Missing Data in GSOD Data" Tags="|meteorology|hydrology|snow|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12684" PostTypeId="1" AcceptedAnswerId="12694" CreationDate="2017-11-15T10:43:02.730" Score="2" ViewCount="1205" Body="&lt;p&gt;I did some geochemical modelling and found groundwater samples I have are saturated with respect to the mineral gypsum. I need some help with interpretation, more information is given below. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The groundwater comes from an engineered aquifer that is comprised of sand. Prior to construction, the sand was in contact with water containing high sulfate and calcium concentrations (dissolved gypsum). There was also some pyrite oxidation occurring which undoubtedly lead to increased sulfate concentrations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does my geochemical modelling work give evidence that the groundwater dissolved $Ca$ and $SO_4$ concentrations are in equilibrium with solid phase gypsum? meaning the mineral is present even though it was completely dissolved initially?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;thanks&lt;/p&gt;&#xA;" OwnerUserId="11471" LastEditorUserId="2470" LastEditDate="2017-11-15T11:03:03.697" LastActivityDate="2017-11-16T08:08:22.510" Title="Gypsum saturation index" Tags="|geochemistry|mineralogy|groundwater|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12685" PostTypeId="1" CreationDate="2017-11-15T11:04:52.393" Score="24" ViewCount="13139" Body="&lt;p&gt;The human body temperature is about &lt;a href=&quot;https://en.wikipedia.org/wiki/Human_body_temperature&quot; rel=&quot;noreferrer&quot;&gt;37 °C&lt;/a&gt; (99 °F), so as the population increases does this cause the Earth's temperature to rise?&lt;/p&gt;&#xA;" OwnerUserId="11473" LastEditorUserId="3106" LastEditDate="2017-11-16T08:33:50.577" LastActivityDate="2021-11-04T05:30:55.743" Title="Does human body temperature impact climate change?" Tags="|climate-change|temperature|human-influence|earth-system|" AnswerCount="9" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12686" PostTypeId="2" ParentId="12685" CreationDate="2017-11-15T12:06:26.227" Score="38" Body="&lt;p&gt;Does human body temperature impact climate change? Directly? It's not even a blip. The Earth's population is 7.6 billion. With each person radiating about 80 watts (basal metabolism), that's about 600 gigawatts, or 760 gigawatts using a round figure of 100 watts. That sounds like a lot, but it's only a tiny fraction of the 18 terawatts consumed by humanity, which in turn is a tiny fraction of the 174 petawatts the Earth receives from the Sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Indirectly, yes. A growing population and the desire for greater wealth by a growing population (third world nations and developing nations want to move themselves out of those categories) are key drivers of climate change. &lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-11-15T12:06:26.227" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="12688" PostTypeId="2" ParentId="12653" CreationDate="2017-11-15T17:33:28.443" Score="2" Body="&lt;p&gt;Concerning&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Is there any good current research out there&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;the most recent study I found is&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;&lt;a href=&quot;http://www.pnas.org/content/114/1/E9.full&quot; rel=&quot;nofollow noreferrer&quot;&gt;Persistence and biodegradation of oil at the ocean floor following Deepwater Horizon&lt;/a&gt;&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In this work, we assess the extent of degradation over 4 y postspill&#xA;for each of 125 petroleum hydrocarbons that contaminated the seafloor.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and compares levels from thousands of sample sites. This seems to qualify 'good current research'.&lt;/p&gt;&#xA;" OwnerUserId="6057" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-11-15T17:33:28.443" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12689" PostTypeId="1" AcceptedAnswerId="12703" CreationDate="2017-11-15T19:37:55.150" Score="4" ViewCount="320" Body="&lt;p&gt;The two images below correspond to two processed seismic cross-sections.&#xA;My question is this: why at/near 0 Hz is there &quot;lots&quot; of seismic energy still present? Most if not all of the lower end of the bandwidth stops at 10 - 15 Hz.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/e5R5j.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/e5R5j.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8447" LastEditorUserId="28050" LastEditDate="2018-04-05T00:33:43.717" LastActivityDate="2018-04-05T00:33:43.717" Title="Seismic data spectral analysis" Tags="|seismic|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12694" PostTypeId="2" ParentId="12684" CreationDate="2017-11-16T08:08:22.510" Score="1" Body="&lt;p&gt;A geochemical model, like phreeqc calculates the saturation index (SI) for minerals based on the composition of the solution, temperature, and possibly pressure. These are used to calculate the activities of the ions, based on the activity coefficients. These are then compared to the activities that would be present at saturation as defined by the solubility product (Ksp). The saturation index is &amp;lt; 0 if the solution is undersaturated with respect the mineral, = 0 at saturation, and &gt; 0 if supersaturated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So when you say the model shows you are saturated with respect to gypsum, it indicates that by definition you are in equilibrium with solid phase gypsum. It does not indicate if you got there by dissolving gypsum or by precipitating gypsum. It is highly unlikely (but theoretically possible) that your SI is exactly 0 without one of those things happening.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-11-16T08:08:22.510" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12695" PostTypeId="2" ParentId="12685" CreationDate="2017-11-16T09:28:11.987" Score="0" Body="&lt;p&gt;As others have pointed out the impact of our own bodies producing heat can be neglected. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said the fact that we are only comfortable at certain temperatures and try to chance our body environment(via heating or cooling) to match does produce a lot of CO2 which impacts the climate much more strongly.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly the energy we use to heat our body comes from our food which we often produce using fossil fuels which does impact the climate.&lt;/p&gt;&#xA;" OwnerUserId="976" LastActivityDate="2017-11-16T09:28:11.987" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12696" PostTypeId="1" AcceptedAnswerId="12922" CreationDate="2017-11-16T12:59:24.087" Score="2" ViewCount="1607" Body="&lt;p&gt;I refer to the this &lt;a href=&quot;https://www.brisbanetimes.com.au/environment/weather/unusual-climate-mix-has-experts-baffled-as-summer-set-for-warmer-drier-conditions-20171116-gzmf7l.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;very recent article&lt;/a&gt;, which quotes Andrew Watkins (Manager of Climate Prediction Services at the Australian Bureau of Meteorology).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My understanding has always been that air flows away from high pressure towards lower pressure, so the following quote from the referenced article confuses me. Can anyone explain it for me?&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;There's been a big high pressure system drawing air in off the ocean, &#xA;  keeping it a bit cooler for Sydney,&quot; Dr Watkins said.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7027" LastActivityDate="2017-12-17T11:33:30.003" Title="Do high pressure systems draw air towards them?" Tags="|meteorology|weather-forecasting|barometric-pressure|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12697" PostTypeId="2" ParentId="12685" CreationDate="2017-11-16T14:37:56.113" Score="-2" Body="&lt;p&gt;No they do not , just like 1 icecube won't freeze an ocean that's what all the human population is to this planet.&lt;/p&gt;&#xA;" OwnerUserId="11492" LastActivityDate="2017-11-16T14:37:56.113" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12698" PostTypeId="2" ParentId="12696" CreationDate="2017-11-16T14:44:14.483" Score="1" Body="&lt;p&gt;It would be nice to have a synoptic chart relevant for the comment. My guess is that the high pressure cell was not drawing air towards itself. Instead, the location of the high pressure cell was such that it caused cooler air from the ocean to be moved towards Sydney. Fort this to happen, the high pressure cell would have been south of Sydney&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-11-16T14:44:14.483" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12699" PostTypeId="1" AcceptedAnswerId="12707" CreationDate="2017-11-16T14:45:31.270" Score="3" ViewCount="2940" Body="&lt;p&gt;I would like to install the &lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/&quot; rel=&quot;nofollow noreferrer&quot;&gt;WRF model&lt;/a&gt; on my Mac computer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where can I find up to date and step-by-step instructions on how to install it?&lt;/p&gt;&#xA;" OwnerUserId="11493" LastEditorUserId="192" LastEditDate="2017-12-17T22:25:07.590" LastActivityDate="2017-12-17T22:25:07.590" Title="How to install WRF on a Mac?" Tags="|models|wrf|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12700" PostTypeId="2" ParentId="12685" CreationDate="2017-11-16T15:16:18.773" Score="1" Body="&lt;p&gt;If I'm understanding your question correctly, you're not asking if human activity impacts the climate. Demonstrably it does, through burning fossil fuels to satisfy energy demand, etc. You're just wondering if humans, only by being warm, have any impact.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Well, an activity-less human is a warm bag of mostly water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you put a warm bag somewhere, it will cool down and there will be no long-term impact to the climate. At best you'll affect the weather that day. Then there will cease to be warm bags.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The devil is in the details of what sustains the ongoing presence of warm bags. If you're making warm bags by burning fossil fuels, clearly that's a problem. If you're focusing light and warming them with solar energy, that may be less of a problem. If you're keeping them warm by metabolizing plants, it will depend greatly on the particular agricultural practices used.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, I don't think your question can have an answer. Human activity is inseparable from sustained human existence on Earth.&lt;/p&gt;&#xA;" OwnerUserId="11490" LastActivityDate="2017-11-16T15:16:18.773" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12701" PostTypeId="1" AcceptedAnswerId="12735" CreationDate="2017-11-16T20:37:11.230" Score="3" ViewCount="63" Body="&lt;p&gt;&lt;strong&gt;How can I adjust black carbon surface mass air pollution concentrations (ug/m3) for rainfall effects?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Specifically, I have monthly and daily averaged black carbon pollution data (i.e. 2.0ug/m3 Jan 2016, Feb 2016, etc) obtained from MERRA-2 reanalysis dataset. I also have averaged monthly rainfall data (i.e. cm per month).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Generally, the air pollution decreases in the higher rainfall months and increases during dry months. I'm interested to remove the rainfall effect from the air pollution values.&lt;/strong&gt; The end goal is to compare the different months to explore biomass burning effects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any suggestions would be greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="11499" LastActivityDate="2017-11-21T14:44:11.217" Title="How can I account for rainfall effects on air pollution?" Tags="|meteorology|air-pollution|statistics|air-quality|reanalysis|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12702" PostTypeId="2" ParentId="12696" CreationDate="2017-11-16T22:07:55.440" Score="0" Body="&lt;p&gt;Conservation of mass. If air is moving away from a high pressure system at some altitude, it must be getting replaced at another or from another direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Without seeing the details, I think what is happening is that there is a high pressure system over the centre of the continent that results in high temperatures. The hot air rises producing on-shore winds from the cooler ocean (adabatic? adiabatic? not sure of the correct terminology).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a lay-person overview of the different major climate influences for Australia, check out the &lt;a href=&quot;http://www.climatekelpie.com.au/understand-climate/climatedogs&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climatedogs&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-11-16T22:07:55.440" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12703" PostTypeId="2" ParentId="12689" CreationDate="2017-11-16T23:03:37.160" Score="5" Body="&lt;p&gt;Typically seismic data should oscillate around 0 amplitude in the time domain, i.e. there should be just as much positive amplitude as there is negative (otherwise the ground would have had a net displacement in some direction). This is the energy at 0 Hz in the amp spectrum. It is like a bulk shift (DC shift) on the data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So... unless the ground was permanently displaced by your seismic source, this is probably just an artifact. It could be as simple as: you used too few data to calculate your amplitude spectrum (e.g. small window, etc). Or it could be a super low frequency artifact coming from data processing.&lt;/p&gt;&#xA;" OwnerUserId="4636" LastActivityDate="2017-11-16T23:03:37.160" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12704" PostTypeId="1" CreationDate="2017-11-17T01:28:46.340" Score="16" ViewCount="3148" Body="&lt;p&gt;In a general 40 mile radius of Keokuk, Iowa many sedimentary geodes can be found.  They are abundant in the &lt;a href=&quot;https://ngmdb.usgs.gov/Geolex/UnitRefs/WarsawRefs_4300.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Warsaw Formation&lt;/em&gt;&lt;/a&gt; with the type section at Geode Glenn in Warsaw, Illinois.  In one specific area in Hancock County, Illinois geodes filled with oil can be found.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OJ4a7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OJ4a7.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6s5Sb.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6s5Sb.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;According to the &lt;a href=&quot;https://www.geodegallery.com/keokuk.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt; of these images:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Research indicates that nearby oil deposits from Pennsylvanian-age&#xA;rocks may somehow be linked to these interesting geodes.  Oil is able&#xA;to migrate quite readily through certain soils and rock, and the&#xA;conditions at the oil geode location may indicate a favorable&#xA;environment for oil to reach the surface as the host rock that&#xA;contains the geodes at this location is also frequently covered with a&#xA;slick of oil.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Unfortunately, I'm not able to find the source of the research backing this statement.  It seems plausible that oil from an overlying formation could be the source of the oil in the geodes and enter the geode via the pore space or any cracks.  Please correct me if this supposition is off base.&lt;/p&gt;&#xA;&lt;p&gt;I've also heard that oil filled geodes have been found in quarries in eastern Iowa.  However, I have not seen evidence of these geodes myself or seen anything written about them.  My question is if anybody could provide any information about oil filled geodes from any other locations globally?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Revision:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I discovered another location associated with the &lt;em&gt;New Albany Shale&lt;/em&gt; in Kentucky where geodes containing bitumen have been found.  There is also a geochemical report investigating the source of the bitumen included with &lt;a href=&quot;http://www.indiana.edu/%7Esepm04/PDF/JS-G5-SEPM%20Guidebook-geode.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this publication&lt;/a&gt;.  Hopefully there are still more sites out there or are the conditions that create these geodes really this rare?&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastEditorUserId="22648" LastEditorDisplayName="user11318" LastEditDate="2021-07-23T11:47:37.790" LastActivityDate="2021-07-23T11:47:37.790" Title="What is the global distribution of oil filled geodes?" Tags="|geology|rocks|petrology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="12705" PostTypeId="2" ParentId="12701" CreationDate="2017-11-17T03:37:31.497" Score="2" Body="&lt;p&gt;Sounds like you want a dataset that is unadjusted for rainfall.  I'm not sure what you have to gain from that, but there are ways to do it.  One way to do this would be to find the inverse correlation between rain and black carbon concentrations, and extrapolate to zero rainfall.  Or, if you have any months that have zero rainfall, you could use that for other months where temperature is similar (thus the mixing layer should be similar).  This would all need to be done for each location separately, so that source contributions weren't mixed up.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-11-17T03:37:31.497" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12707" PostTypeId="2" ParentId="12699" CreationDate="2017-11-17T06:08:53.537" Score="3" Body="&lt;p&gt;The WRF Forum &lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/wrfv3.4/testing.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; describes some testing using a Mac, and they report success with 2 setups:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mac 64-bit running OSX, with Intel chips, g95 gcc version 4.0.3 (g95 0.92!)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mac 64-bit running OSX, with Intel chips, PGI pgf90 10.3&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is also some additional information on installing ARWpost on a Mac found on the &lt;a href=&quot;http://forum.wrfforum.com/viewtopic.php?f=30&amp;amp;t=5563&quot; rel=&quot;nofollow noreferrer&quot;&gt;WRF Forum&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Separately, there is a blog dedicated to your question &lt;a href=&quot;http://macwrf.blogspot.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; and instructions on github &lt;a href=&quot;https://github.com/Toberumono/WRF-Setup-Script&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.  Also, if you see the tutorial &lt;a href=&quot;https://catastrophescience.wordpress.com/2014/02/19/compiling-wrf-arw-mac/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, you can see a method that requires you to install &lt;a href=&quot;https://developer.apple.com/xcode/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Xcode&lt;/a&gt;.  &lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-11-17T06:08:53.537" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12708" PostTypeId="2" ParentId="12685" CreationDate="2017-11-17T15:24:04.227" Score="0" Body="&lt;p&gt;It's more the &lt;em&gt;lack&lt;/em&gt; of human body temperature (or rather heat, as the temperature is rather constant while alive) that impacts climate change.  The most efficient way of keeping a human body warm in cold weather is directly insulating it and heating with internal combustion.  Homeless people tend to do that, and their carbon footprint is exemplary.  &lt;em&gt;That's&lt;/em&gt; what you are talking about with regard to &quot;human body temperature&quot; affecting climate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most energy-conscious &quot;proper&quot; citizen, however, keeps a house heated rather than himself.  The surface area of a house is large: insulating it is quite a larger task than insulating a single human (and requires a lot of material that needs to be produced, too).  You'll need a whole lot more fuel for that even though you don't heat it to 37°C proper.&lt;/p&gt;&#xA;" OwnerDisplayName="user11512" LastActivityDate="2017-11-17T15:24:04.227" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12711" PostTypeId="1" CreationDate="2017-11-17T18:04:18.247" Score="1" ViewCount="43" Body="&lt;p&gt;In &lt;a href=&quot;https://earthscience.stackexchange.com/questions/12215/what-makes-a-nuclear-winter-so-extreme-and-destructive&quot;&gt;other question&lt;/a&gt; we've been discussing factors of the nuclear winter effect, soot among them.&#xA;In this one I'd like to narrow the list down to soot, more precisely to ask about its ability to absorb ultraviolet and re-radiate infrared.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An argument by the other member goes like this:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Nuclear winter (solar radiation blocked by soot) wouldn’t be that&#xA;  troublesome. High altitude soot is the “perfect” absorber and&#xA;  reradiator of infrared energy. Nights would be warmer –as are normal&#xA;  cloudy nights- and days a bit cooler. &lt;strong&gt;Some energy would be lost by&#xA;  reradiation to space but most conserved by earthward reradiation of&#xA;  ultraviolet converted to infrared by soot absorption.&lt;/strong&gt; – TomO&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It is not clear to me in what ways can this property of soot contribute to the nuclear winter effect or have an impact on climate. Especially I had hard time in understanding the last part of the argument, bolded (by me) Can anyone explain this mechanism and elaborate on it? Are there studies/sources that back the statement or challenge it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="11453" LastActivityDate="2017-11-17T18:04:18.247" Title="In which ways is soot the perfect absober of infrared and the absorber of ultraviolet?" Tags="|climate-change|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12712" PostTypeId="1" AcceptedAnswerId="12713" CreationDate="2017-11-18T01:01:06.667" Score="6" ViewCount="327" Body="&lt;p&gt;I have seen several graphs showing the prehistoric temperatures and CO2 concentrations derived from ice-core data.  &lt;a href=&quot;https://i.stack.imgur.com/5SD2t.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5SD2t.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;  My understanding is that CO2 and temperature correlate.  I assume that Milankovich Cycles are what caused the variations observed in temperature in the ice record, but what specifically caused the CO2 to fluctuate?&lt;/p&gt;&#xA;" OwnerUserId="510" LastEditorUserId="11908" LastEditDate="2019-03-13T05:19:23.733" LastActivityDate="2024-03-12T02:50:40.937" Title="What caused the Carbon Dioxide Variations observed in the 800,000-year polar ice record?" Tags="|climate-change|glaciology|paleoclimatology|carbon-cycle|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12713" PostTypeId="2" ParentId="12712" CreationDate="2017-11-18T02:49:55.277" Score="3" Body="&lt;p&gt;&lt;a href=&quot;http://earthguide.ucsd.edu/virtualmuseum/climatechange2/07_2.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; investigates the ocean's dissolved carbon content (ocean reservoir) and the seafloor's methane hydrates (&quot;methane ice&quot;) as a source of CO2 fluctuations in ice cores. They discuss three ways the ocean may release CO2. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;through physics (changes in temperature and ocean currents)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;biologically or chemically&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;through general climate changes&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Hope this helps.&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2017-11-18T02:49:55.277" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12715" PostTypeId="1" CreationDate="2017-11-18T04:40:40.977" Score="1" ViewCount="69" Body="&lt;p&gt;What are the causes of &lt;a href=&quot;http://www.cnn.com/2017/11/12/middleeast/iraq-earthquake/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;the earthquake in Kuwait&lt;/a&gt;  on Nov 12, 2017?&lt;/p&gt;&#xA;" OwnerUserId="11517" LastEditorUserId="543" LastEditDate="2017-11-18T06:08:47.703" LastActivityDate="2017-11-18T06:08:47.703" Title="What caused the earthquake in Kuwait on Nov 12, 2017?" Tags="|earthquakes|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12716" PostTypeId="1" CreationDate="2017-11-18T08:15:39.000" Score="0" ViewCount="214" Body="&lt;p&gt;I want to know the signs before earthquakes and how long it would talk&lt;/p&gt;&#xA;" OwnerUserId="11517" LastActivityDate="2017-11-18T12:19:29.783" Title="Can we predict the earthquake before it occurs a while? What is the maximum period?What are the signs of an earthquake soon?" Tags="|earthquakes|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12718" PostTypeId="2" ParentId="12716" CreationDate="2017-11-18T12:19:29.783" Score="1" Body="&lt;p&gt;Short answer is no.  Earthquakes often occur in clusters but the problem is there is no way of knowing when the largest quake has occurred until the series of quakes is completed.  Studies in fault areas measuring changes in magnetic fields, changes in the local water table, radon gas and radio wave emissions have shown to not be reliable indicators of an impending earthquake.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://earthquake.usgs.gov/learn/topics/animal_eqs.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;United States Geological Survey&lt;/a&gt; (USGS) has a publication discussing the possibility that animals feel earthquakes before people.  The basic premise is that animals can feel the P waves, the fastest waves coming from an earthquake, that few humans can feel.  However, a baseline behavior for each animal would need to be measured and the stimuli that an animal would react to would have to be present before the earthquake.  So again, animals are not a reliable precursor to an earthquake. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given no reliable indicator of an impending earthquake, the most important development in saving lives is the use of early warning systems.  There are several countries that have been implementing these for years including Japan, Mexico, and China.  Many seismologists believe that a warning of up to a minute could be given.  Three of the many factors that determine the effectiveness of an early warning are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Distance between the earthquake source and the closest seismic&#xA;network seismometer (station)&lt;/li&gt;&#xA;&lt;li&gt;Transfer of information to the regional networks&lt;/li&gt;&#xA;&lt;li&gt;Detection and characterization of an earthquake&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;This graph presents estimated warning times from distance of epicenter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Iilyu.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Iilyu.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Estimated warning times for locations at different distances from the earthquake epicenter. Locations within 20 miles of the fault will likely not receive any warning as, on average, it will take 10 seconds to detect and locate the earthquake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source:&lt;a href=&quot;https://earthquake.usgs.gov/research/earlywarning/background.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earthquake.usgs.gov/research/earlywarning/background.php&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2017-11-18T12:19:29.783" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12720" PostTypeId="1" CreationDate="2017-11-18T19:05:59.030" Score="7" ViewCount="72" Body="&lt;p&gt;What is the mean amount (in grams) of dissolved carbon in a ton of sea water ?&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The value I want is the concentration value in say the first two metres of surface water (A distribution of this concentration by depth would also help)&lt;/li&gt;&#xA;&lt;li&gt;If I take say the 10% surface area where the CO&lt;sub&gt;2&lt;/sub&gt; concentration is the highest on the globe, what does it change about the result ?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Please feel free to answer even if your answer is not the complete one but just part of it.&#xA;Thanks&lt;/p&gt;&#xA;" OwnerUserId="11522" LastEditorUserId="5594" LastEditDate="2017-12-19T21:09:45.147" LastActivityDate="2017-12-19T21:15:22.987" Title="What is the mean amount (in grams) of dissolved carbon in a ton of sea water?" Tags="|ocean-models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12721" PostTypeId="1" CreationDate="2017-11-19T08:02:06.200" Score="0" ViewCount="171" Body="&lt;p&gt;I've a question about time calculating.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The sun rises up at &lt;strong&gt;7:30&lt;/strong&gt; in &lt;strong&gt;25°E&lt;/strong&gt;, What time will the sun rise up in&#xA;  &lt;strong&gt;15°E&lt;/strong&gt;?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What I've tried&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$25° - 15° = 10°$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By the way&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$10° . 4 = 40 \space \text {minutes}$$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it seems wrong. &lt;/p&gt;&#xA;" OwnerUserId="11526" LastEditorUserId="94" LastEditDate="2017-11-19T08:28:18.643" LastActivityDate="2017-11-19T11:10:10.267" Title="The sun rises up at 7:30 in 25°E, What time will the sun rise up in 15°E?" Tags="|geography|homework|sun|time|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12722" PostTypeId="1" CreationDate="2017-11-19T11:03:13.890" Score="1" ViewCount="421" Body="&lt;p&gt;If the solubility constant for a mineral is exceeded and, thermodynamically, a mineral is favored to precipitate in solution, are there any factors that may limit this from happening? Perhaps kinetics? Is it known if calcite precipitates out faster than dolomite does? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also what will happen once a mineral precipitates out? Will concentrations decrease until the solution is saturated with respect to the mineral? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="11471" LastActivityDate="2017-11-22T01:19:56.560" Title="Limitations on mineral precipitation from solution" Tags="|geochemistry|mineralogy|minerals|groundwater|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12723" PostTypeId="2" ParentId="12721" CreationDate="2017-11-19T11:10:10.267" Score="1" Body="&lt;p&gt;Your maths is not detailed, but you have the correct answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth rotates at 15 degrees per hour (360 degrees/24 hours).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The time required to rotate 10 degrees is 10/15 = 0.666 hours, which is 40 minutes.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-11-19T11:10:10.267" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12724" PostTypeId="5" CreationDate="2017-11-19T13:05:56.120" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2017-11-19T13:05:56.120" LastActivityDate="2017-11-19T13:05:56.120" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12725" PostTypeId="4" CreationDate="2017-11-19T13:05:56.120" Score="0" Body="The movement of materials such as rocks, sands, and soils from and along the Earth's surface due to physical processes such as, but not limited to, rain, ice, wind, and gravity.  " OwnerDisplayName="user11318" LastEditorUserId="2470" LastEditDate="2017-11-19T14:48:19.017" LastActivityDate="2017-11-19T14:48:19.017" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12726" PostTypeId="2" ParentId="12720" CreationDate="2017-11-19T18:47:51.250" Score="2" Body="&lt;p&gt;This graph at Wikipedia/Wikimedia is part of the answer :&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/f0DIz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/f0DIz.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;source: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Oceanic_carbon_cycle#/media/File:WOA05_GLODAP_pd_DIC_AYool.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;en.wikipedia.org/wiki/Oceanic_carbon_cycle#/media/File:WOA05_GLODAP_pd_DIC_AYool.png&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/File:WOA05_GLODAP_pd_DIC_AYool.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;en.wikipedia.org/wiki/File:WOA05_GLODAP_pd_DIC_AYool.png&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;2.15 mol/m&lt;sup&gt;3&lt;/sup&gt; at the surface in 1990 seems like a approximative value, which makes approximately 27 g. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, the two questions left are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;How did this value evolve since 1990?&lt;/li&gt;&#xA;&lt;li&gt;Does this concentration change a lot with depth?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="11522" LastEditorUserId="5594" LastEditDate="2017-12-19T21:15:22.987" LastActivityDate="2017-12-19T21:15:22.987" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12727" PostTypeId="2" ParentId="12722" CreationDate="2017-11-19T19:44:30.377" Score="2" Body="&lt;p&gt;This is really a wide open question on which books could be written. First let's stipulate that we are considering aqueous solutions rather than say magma. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In aqueous solution the solubility of a particular mineral depends on the temperature, pressure and chemical composition of the liquid. Generally as a solution would rise towards the surface of the earth the pressure and temperature drop which tends to decrease the solubility. Once the solution becomes saturated with respect to a certain mineral then it becomes thermodynamically favorable for the mineral to deposit. However it is possible for a solution to become supersaturated. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also you have to remember that homogeneous conditions wouldn't really exist. There would be temperature and pressure differences in water flowing through a crevice. The water wouldn't flow at a constant rate over long periods of time. So the whole aspect of deposition and dissolution would be very dynamic. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is also possible to dissolve minerals A and B, yet deposit some mineral C. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also for minerals there are often many different crystal formations. Calcite deposits in hundreds of different types of crystals. &lt;/p&gt;&#xA;" OwnerUserId="4685" LastActivityDate="2017-11-19T19:44:30.377" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12729" PostTypeId="1" CreationDate="2017-11-20T07:45:42.690" Score="1" ViewCount="33" Body="&lt;p&gt;The 20-Nov-2017 Reuters News item &lt;a href=&quot;https://www.reuters.com/article/us-newcaledonia-quake/small-tsunamis-detected-in-new-caledonia-and-vanuatu-after-magnitude-7-undersea-quake-idUSKBN1DJ0W0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Small tsunamis detected in New Caledonia and Vanuatu after magnitude 7 undersea quake&lt;/a&gt; says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Small tsunamis were detected and waves may have reached up to one meter (three feet) above the high tide level in parts of New Caledonia and smaller in Vanuatu, the PTWC said.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The PTWC is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Pacific_Tsunami_Warning_Center&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Pacific Tsunami Warning Center&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Were Tsunami-like changes in sea level detected automatically and forwarded to some center before they reached any shoreline, or does &quot;detected&quot; refer to the relatively small tsunami wave shown in (for example) &lt;a href=&quot;https://www.youtube.com/watch?v=DK1-QgwPsEQ&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; or &lt;a href=&quot;https://www.youtube.com/watch?v=tBquGF4EJ8g&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; YouTube video?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2017-11-27T08:12:34.597" LastActivityDate="2017-11-27T08:12:34.597" Title="Was the small Vanuatu Tsunami detected by remote monitors in the ocean before it reached land?" Tags="|tsunami|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12731" PostTypeId="1" AcceptedAnswerId="12732" CreationDate="2017-11-21T10:10:08.767" Score="4" ViewCount="844" Body="&lt;p&gt;Is there any website where can I download ECHAM climate model data?&lt;/p&gt;&#xA;" OwnerUserId="11493" LastEditorUserId="5594" LastEditDate="2017-12-13T22:03:27.280" LastActivityDate="2017-12-13T22:03:27.280" Title="where can I download ECHAM climate model data?" Tags="|climate-models|open-data|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12732" PostTypeId="2" ParentId="12731" CreationDate="2017-11-21T10:37:24.483" Score="5" Body="&lt;h1&gt;Where to find the data&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The German Climate Research Center (&lt;a href=&quot;https://www.dkrz.de/up&quot; rel=&quot;noreferrer&quot;&gt;DKRZ&lt;/a&gt;, Deutsches Klimarechenzentrum) hosts the Word Data Center for Climate (&lt;a href=&quot;https://www.dkrz.de/up/systems/wdcc&quot; rel=&quot;noreferrer&quot;&gt;WDCC&lt;/a&gt;). You can search the WDCC via the CERA Database (&lt;a href=&quot;https://cera-www.dkrz.de/&quot; rel=&quot;noreferrer&quot;&gt;cera-www.dkrz.de&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looking for ECHAM provides you with several sets of ECHAM model results: &lt;a href=&quot;https://cera-www.dkrz.de/WDCC/ui/cerasearch/q?query=ECHAM&amp;amp;page=0&amp;amp;rows=50&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;. You get at least the ECHAM data for the second to fourth IPCC assessment reports and some more data sets.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You need to have a login. It can be easily created.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Information on the structure of the data at CERA&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;You have &lt;strong&gt;projects&lt;/strong&gt;, &lt;strong&gt;experiments&lt;/strong&gt;, and &lt;strong&gt;data&lt;/strong&gt; (sets).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Projects&lt;/em&gt; contain overall information on the model setup, on the data producers, and on the validation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One &lt;em&gt;experiment&lt;/em&gt; can summarize several &lt;em&gt;data&lt;/em&gt; sets. For a coupled climate model this could mean, that the physical ocean, the biogeochemical ocean, the meteorology, and the atmospheric chemistry are saved as individual &lt;em&gt;data&lt;/em&gt; sets, which are than summarized as one &lt;em&gt;experiment&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Experiments can have a doi (&lt;a href=&quot;http://www.doi.org/&quot; rel=&quot;noreferrer&quot;&gt;digital object identifier&lt;/a&gt;). Thus, they are easily citeable in scientific publications and long-term available.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Access data at the WDCC&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;You can directly download data via the web-interface. As an alternative, you can use &lt;a href=&quot;https://cera-www.dkrz.de/WDCC/ui/cerasearch/info?site=jblob&quot; rel=&quot;noreferrer&quot;&gt;jblob&lt;/a&gt;, which is a command line utility for downloading data from the WDCC. Jblob also has some options to pre-process data on the DKRZ servers prior to download it -- which might reduce your file size. For both access pathways you need to have a valid login.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2017-11-21T10:37:24.483" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12733" PostTypeId="2" ParentId="4822" CreationDate="2017-11-21T12:41:32.347" Score="-7" Body="&lt;p&gt;There are 3 independent forces at play on moveable objects like continents on the surface of a rotating sphere.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Coriolis force: moves continents in the N. Hemisphere towards the N.Pole and those in the S. Hemisphere towards the S. Pole. There is no angular momentum that pushes all crustal mass towards just one pole.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Subduction/Emission ie. Deep Thermal forces move continents from emission zones to subductions zones. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Rebalancing forces after heavy meteor bombardments in Either Hemisphere will rebalance by shifting crustal plates away from the Hemisphere that has been hit. In two dimensions if you put a 'balancing lead slug' on a slider ring on an unbalanced car wheel then the slug will move to the balance position when the wheel is in motion. Equatorial meteor hits will have only muted effects.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The first two of these forces must eventually lead to both hemispheres having equal total crustal plate masses. Given average sial density of 2.2 that means roughly equal crustal areas should be present by now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus the current 60:30 N:S distribution indicates a recent heavy meteorite strike to the S Hemisphere. S.Africa stands out as the hit zone due to the shape of the E.Rift Valley and extensive heavy metal placements in that area. The rough equispacing of Africa, Australia and S.America also tend to support this given the ratio of their areas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Third force will enable one hemisphere to be weighted with more crust to counteract a heavy meteor presence in the other hemisphere.&lt;/p&gt;&#xA;" OwnerUserId="11537" LastActivityDate="2017-11-21T12:41:32.347" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12735" PostTypeId="2" ParentId="12701" CreationDate="2017-11-21T14:44:11.217" Score="1" Body="&lt;p&gt;Thank you all for your suggestions, I greatly appreciate it. I was able to get a solution to this problem which essentially obtains correlated errors (using ARMA correlation) in a linear (or non-linear model) and the resulting residual values are subtracted from the original values to provide some adjustment for effects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please see this post for more details: &lt;a href=&quot;https://stats.stackexchange.com/questions/314338/how-can-i-adjust-values-in-a-timeseries-to-account-for-effects-from-other-variab/314359?noredirect=1#comment597434_314359&quot;&gt;https://stats.stackexchange.com/questions/314338/how-can-i-adjust-values-in-a-timeseries-to-account-for-effects-from-other-variab/314359?noredirect=1#comment597434_314359&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="11499" LastActivityDate="2017-11-21T14:44:11.217" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12736" PostTypeId="2" ParentId="12673" CreationDate="2017-11-21T19:58:12.563" Score="1" Body="&lt;p&gt;I agree that terminology about evapotranspiration is confusing especially when using the expression &quot;potential evapotranspiration&quot;, as stated in the FAO-56 paper:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The use of other denominations such as potential ET is strongly discouraged due to ambiguities in their definitions&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;h1&gt;Definition&lt;/h1&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;So let's refer to the FAO terminology:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;em&gt;Reference evapotranspiration&lt;/em&gt; ($ET_0$) refers to the evapotranspiration observed on &lt;strong&gt;well watered grass&lt;/strong&gt;  for given meteorological conditions (radiation, temperature, humidity, and wind speed).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;em&gt;Crop evapotranspiration under standard conditions&lt;/em&gt; ($ET_c$) refers to the evapotranspiration observed on &lt;strong&gt;well watered specific crop&lt;/strong&gt; for given meteorological conditions. The relationship between $ET_c$ and $ET_0$ is given by:&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;ET_c = K_C\times ET_0 \tag{1}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;&lt;em&gt;Crop evapotranspiration under non-standard conditions&lt;/em&gt; ($ET_{c,adj}$) refers to the evapotranspiration observed on a &lt;strong&gt;specific crop under water and environmental stress&lt;/strong&gt; for given meteorological conditions. The relationship to $ET_0$ is either defined using a stress coefficient $K_s$:&#xA;$$&#xA;ET_{c,adj} = K_s \times K_c \times ET_0 \tag{2}&#xA;$$&#xA;Or using an adjusted crop coefficient $K_{c,adj}$:&#xA;$$&#xA;ET_{c,adj} = K_{c,adj} \times ET_0 \tag{3}&#xA;$$&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;h1&gt;Confusions&lt;/h1&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Now, you may find different common usage for the terms potential or actual evapotranspiration that leads to your confusion. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Potential evapotranspiration&lt;/em&gt; is sometimes referred to $ET_0$ or $ET_c$ or even less strict definition such as atmospheric demand for water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Actual evapotranspiration&lt;/em&gt;  is referred either to $ET_c$, $ET_{c,adj}$ or less strict definition such as the amount of water evaporated.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Pragmatism&lt;/h1&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Regarding your issue, pick one:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Read to find out what are the definitions involved in WEAP and HAR&lt;/li&gt;&#xA;&lt;li&gt;Look at the data and find out if potential evapotranspiration refers to grass (definition 1) or to specific crop with a given coefficient (definition 2, eq.1)&lt;/li&gt;&#xA;&lt;li&gt;Use the other HAR data (everything is available) to compute $ET_0$ using FAO-56 method.&lt;/li&gt;&#xA;&lt;li&gt;Last but not least, do not bother that much as evapotranspiration is full of uncertainties and you could not proove which of $ET_0$, $ET_c$ or $ET_{c,adj}$ best represent your actual evapotranspiration. You are interested in the relative dynamics of $ET$, choose realistic ranges of landcover coefficient and calibration will do the mass balance. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="3363" LastEditorUserId="3363" LastEditDate="2017-11-21T20:56:19.967" LastActivityDate="2017-11-21T20:56:19.967" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12737" PostTypeId="2" ParentId="12722" CreationDate="2017-11-22T01:19:56.560" Score="2" Body="&lt;p&gt;Kinetics certainly can limit precipitation of minerals from solution. This could be due to the inherently slow precipitation for a particular mineral or could be due to more rapid precipitation of another mineral (for example precipitation of aragonite from a supersaturated calcium carbonate solution, even though calcite is the more stable form at low temperatures. Catalysts or biological processes can lower the activation energy barrier for precipitation of a less thermodynamically stable phase so it precipitates faster.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It sometimes takes a significant degree of supersaturation for nucleation of mineral grains for precipitation to proceed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These factors mean that precipitation will not always reach equilibrium between the mineral and the solution.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2017-11-22T01:19:56.560" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12740" PostTypeId="1" CreationDate="2017-11-22T11:55:41.840" Score="13" ViewCount="7489" Body="&lt;p&gt;Sound travels fastest through warm air and conditions such as temperature inversions can help to amplify the sound of thunder (&lt;a href=&quot;https://www.noaa.gov/jetstream/lightning/sound-of-thunder&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;).  Conversely, during a thundersnow event the falling, and accumulated, snow can act as an acoustic suppressor (&lt;a href=&quot;https://en.wikipedia.org/wiki/Thundersnow&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;). Originally I was thinking that the loudest thunder at ground levels would simply be at higher elevations, however the atmospheric conditions mentioned above, and others that I'm not aware of, have me wondering where the loudest thunder would actually occur.&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastEditorUserId="27775" LastEditDate="2023-10-17T06:37:34.397" LastActivityDate="2023-10-17T14:18:41.683" Title="What is the loudest thunder ever recorded (dB) at ground level and where did it occur?" Tags="|meteorology|thunderstorm|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="12741" PostTypeId="1" CreationDate="2017-11-22T12:46:42.227" Score="4" ViewCount="96" Body="&lt;p&gt;Ideally, one pollutant (e.g. organic carbon, heavy metals, sulfate) should be the mixed result of local emissions and regional transportation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To quantify the contribution of local emissions is of great significance especially for the species with serious health issues. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Without the support of complex 3-D model results which may also introduce uncertainty due to the input emission files, I want to discuss some factors to assess the regional impact based on the ground observations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, one aerosol component $X$ was measured in several sites within the study region. Here are some criteria I propose to determine whether local emission or regional sources matters. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1) The spatial variability of the concentration levels. If the mass loading of the species in different sites is small, there might be the obvious impact of regional transportation from the outer regions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) The seasonal pattern with meteorology analysis. The wind direction pattern or the air mass trajectories pattern should be varied in different seasons. A priori knowledge on the emission hotspot for a larger area is also essential. If the elevated concentrations most occur when the study region is in the downstream of the high emission region, the higher level should be ascribed to the regional transportation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any comments, opinions or related technology would be greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="5214" LastEditDate="2017-11-22T12:55:15.077" LastActivityDate="2017-11-22T12:55:15.077" Title="The factors should be considered to determine one specific pollutant originated from regional transportation?" Tags="|atmosphere|air-pollution|atmospheric-chemistry|air-quality|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12742" PostTypeId="1" CreationDate="2017-11-22T12:49:18.280" Score="5" ViewCount="53" Body="&lt;p&gt;I have a large sequence of images in .png (10 second resolution) from sky image system. Is there any inexpensive software for processing images and forecasting cloud motion?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have found out that several universities are developing it, but i don't have access to them. &lt;/p&gt;&#xA;" OwnerUserId="11548" LastEditorUserId="11548" LastEditDate="2017-11-22T12:57:35.297" LastActivityDate="2017-11-22T12:57:35.297" Title="What software for cloud motion forecasting" Tags="|meteorology|clouds|weather-forecasting|software|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12743" PostTypeId="1" CreationDate="2017-11-22T18:12:27.010" Score="3" ViewCount="85" Body="&lt;p&gt;I am looking for global land use projections for a large scale hydrological analysis. The most widely used datasets are the &lt;a href=&quot;http://luh.umd.edu/data.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;LUH (v1) Products used for CMIP5&lt;/a&gt; based on &lt;a href=&quot;https://link.springer.com/article/10.1007/s10584-011-0153-2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hurtt et al 2011&lt;/a&gt;. These products have been recently updated for the preparation of the CMIP6 climate experiments (LUH v2).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;LUH v1 products are available at a spatial resolution of 0.5 degrees. I am looking for something a little more detailed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am aware of a downscaling project implemented by researchers at CSIRO (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/ece3.2104/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hoskins et al 2016&lt;/a&gt;). The output of this exercise is available as &lt;a href=&quot;https://data.csiro.au/dap/landingpage?pid=csiro%3A15276&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global 30s (~1km) resolution land use for 2005&lt;/a&gt;. Unfortunately, this dataset is available only for the year 2005. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could anyone suggest a similar product, even a bit coarser (&amp;lt;=10 km resolution), for the future projections?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT&lt;/strong&gt;: the kind of data I'm looking for has to be based on CMIP5 LU projections (LUH v1) to ensure consistency with the Land Cover used for the climate projections (from the General Circulation of Earth System Models).&#xA;In case this does not exist, does anyone know an efficient algorithm I can use to downscale LUH v1?   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you.  &lt;/p&gt;&#xA;" OwnerUserId="8087" LastEditorUserId="8087" LastEditDate="2017-11-23T08:46:04.083" LastActivityDate="2017-11-23T08:46:04.083" Title="High resolution global land use projections" Tags="|hydrology|land-surface|earth-system|land-surface-models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12744" PostTypeId="2" ParentId="12743" CreationDate="2017-11-22T21:05:31.230" Score="1" Body="&lt;p&gt;While this isn't 10km or less, the &lt;a href=&quot;http://luh.umd.edu/data.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;CMIP6 dataset&lt;/a&gt; is released as of last week. It's now at 0.25degree spatial resolution which is an improvement. &lt;/p&gt;&#xA;" OwnerUserId="11499" LastActivityDate="2017-11-22T21:05:31.230" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12745" PostTypeId="1" CreationDate="2017-11-23T13:49:49.077" Score="4" ViewCount="156" Body="&lt;p&gt;In an engineered wetland,  there is groundwater flow from an aquifer with a chemical composition that is rich in magnesium, calcium and sulfate. We are finding that the aquifer is consistently saturated with respect to dolomite and calcite. Similarily, the wetland is also saturated and slightly oversaturated with respect to those minerals, however concentrations of both mg and ca are higher in the wetland than the aquifer. We were expecting concentrations to be similar given saturation with respect to the carbonate minerals. So we are hypothesizing the following: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alkalinity is much higher in the wetland than in the aquifer, probably due to more extensive CO2 production. Given there is more CO2 in this region, this would enhance the dissolution of dolomite and calcite and therefore cause the increase in both magneaium and calcium. However, we are not sure if those minerals can form in a short period? The system was constructed about one year ago. If the minerals are unlikely to be present and it is by chance that groundwater is oversaturated, then what can be causing the increase in both magnesium and calcium? I know cation exchange should remove those ions from solution and not the other way around. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any help is greatly appreciated. &lt;/p&gt;&#xA;" OwnerUserId="11554" LastActivityDate="2017-11-23T13:49:49.077" Title="Dolomite and calcite precipitation" Tags="|geochemistry|minerals|groundwater|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12746" PostTypeId="1" AcceptedAnswerId="12761" CreationDate="2017-11-23T15:57:02.383" Score="1" ViewCount="303" Body="&lt;p&gt;I am trying to estimate fracture pressure of a reservoir when applying injection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I keep reading &lt;em&gt;fracture pressure=reservoir pressure+2000psi&lt;/em&gt;&#xA;or &lt;em&gt;fracture pressure gradient is 0.7psi/ft&lt;/em&gt;, but I can't find anything to support those values.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can you provide me with a literature or a better way to calculate the fracture pressure?&lt;/p&gt;&#xA;" OwnerUserId="11555" LastEditorUserId="595" LastEditDate="2017-11-23T16:04:54.033" LastActivityDate="2018-01-27T03:16:37.137" Title="Estimating fracture pressure (looking for literature to support)" Tags="|petroleum|barometric-pressure|literature-request|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12749" PostTypeId="1" CreationDate="2017-11-24T12:03:40.897" Score="6" ViewCount="238" Body="&lt;p&gt;The 'Bama Boom ('Bama is short for the US state of Alabama) is a term for some audible &quot;booms&quot; heard by many people in Alabama and now in Colorado. See for example the Popular Mechanics article &lt;a href=&quot;http://www.popularmechanics.com/military/aviation/a13728147/mysterious-powerful-boom-shakes-alabama/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mysterious, Powerful &quot;Boom&quot; Shakes Alabama&lt;/a&gt; and the Tech Times' &lt;a href=&quot;http://www.techtimes.com/articles/216026/20171124/mysterious-booms-heard-in-colorado-leave-residents-baffled.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mysterious Booms Heard In Colorado Leave Residents Baffled&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;In this question I'm just asking about the measurements shown below from the CBS Denver News item &lt;a href=&quot;http://denver.cbslocal.com/2017/11/21/mysterious-booms-heard-in-colorado/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mysterious Booms Around World Now Heard In Colorado&lt;/a&gt;&lt;/em&gt;, not about the &quot;booms&quot; themselves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second plot states it's a seismogram, but I can't tell what the first one likely represents. Could this be an &lt;a href=&quot;https://en.wikipedia.org/wiki/Infrasound&quot; rel=&quot;nofollow noreferrer&quot;&gt;infrasound&lt;/a&gt; measurement? The caption says that it's a &quot;sound graph&quot; but that's not necessarily a technical term.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/4a8EH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; &quot;A sound graph from the USGS Lakeview Retreat near Centreville, Ala., shows a loud boom heard over Alabama at about 1:39 p.m. CST on Nov. 14. The cause of the boom is still unknown. (credit: NASA)&quot; From &lt;a href=&quot;http://denver.cbslocal.com/2017/11/21/mysterious-booms-heard-in-colorado/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/EkLp3.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; &quot;(credit: USGS and CBS)&quot; From &lt;a href=&quot;http://denver.cbslocal.com/2017/11/21/mysterious-booms-heard-in-colorado/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2021-02-08T00:58:59.740" LastActivityDate="2021-02-08T00:58:59.740" Title="Was the &quot;'Bama Boom&quot; even recorded by infrasound or by seismic detectors?" Tags="|atmosphere|measurements|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="12750" PostTypeId="1" CreationDate="2017-11-24T12:13:39.240" Score="1" ViewCount="320" Body="&lt;p&gt;I am trying to create a program that calculates the ideal climate based on a set of inputs and weights. Something similar to &lt;a href=&quot;http://www.400cities.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;400 cities&lt;/a&gt; but based on more climate based options that the user can configure. Some example questions;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;What is your ideal daily mean temperature, answer must be between 0-40(celsius) ? how important is this, answer 1-5 with 5 being the most important ?&lt;/li&gt;&#xA;&lt;li&gt;How important is it for you to be near the mountains, answer 1-5 with 5 being the most important ?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;One of the problems I am having is with the sunshine duration metric as calculated by the Campbell–Stokes recorder.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;DISCLAIMER 1: All stats below are approximations / anecdotal&#xA;DISCLAIMER 2: I may need some statistical calculations explained.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Taking some rough figures from &lt;a href=&quot;https://en.wikipedia.org/wiki/Sunshine_duration&quot; rel=&quot;nofollow noreferrer&quot;&gt;wiki&lt;/a&gt;, Los Angeles has 3254 hours of sunshine and London has 1633 hours per year. Maximum sunshine duration in a day is approximately 4380 hours giving LA a sunshine 74% of the days on average and London sunshine 37% of the day on average so we could roughly say that LA has 2x the sunshine hours of London&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This does not make sense to me. I want to initially create a metric that more accurately represents the quality of weather. I would then like to refine it to give a metric (configurable) like 'good days' that may need to pass params like &gt; 25C, sunny &gt; 70% of day, cloud coverage &amp;lt; 20%, UV strength &gt; 4. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example (my brother lives in LA) in August this year there were 25 days in LA that were 'sunny days', lets say sunny for &gt; 70% of the day. In London there were 4, giving values of 83% and 13% approx so we could roughly say that LA has 6X more sunny days per month than London. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My questions are;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Why do the number of sun hours in London seem so high when anecdotally the difference is much much larger. &lt;/li&gt;&#xA;&lt;li&gt;Where can I find data that is more suitable for my project or alter the data on sunshine hour to suit it.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Many thanks.&lt;/p&gt;&#xA;" OwnerUserId="11562" LastActivityDate="2017-11-24T12:13:39.240" Title="Understanding the sunshine duration metric" Tags="|sun|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="12752" PostTypeId="2" ParentId="12371" CreationDate="2017-11-26T12:11:13.930" Score="2" Body="&lt;p&gt;You have a nice stromatolite fossil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A stromatolites are layered bio-chemical accretionary structures formed in shallow water by the trapping, binding and cementation of sedimentary grains by biofilms (microbial mats) of microorganisms, especially cyanobacteria. stromatolite fossils can be some of the oldest fossils found on earth. Living stromatolites can still be found today.&#xA; (&lt;a href=&quot;https://en.wikipedia.org/wiki/Stromatolite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This pattern on the underside of a stromatolite fossil is very characteristic.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/lPjl0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lPjl0.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cretaceous age stromatolite fossils from Morocco are commonly found for sale online. (&lt;a href=&quot;https://www.etsy.com/listing/527211575/huge-almost-6-lbs-stromatolite-fossil?ref=search_recently_viewed-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Esty&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="1149" LastEditDate="2017-11-26T13:07:47.713" LastActivityDate="2017-11-26T13:07:47.713" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12753" PostTypeId="1" AcceptedAnswerId="12755" CreationDate="2017-11-26T16:46:10.600" Score="2" ViewCount="185" Body="&lt;p&gt;I've looked at/listened to:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;NPR: &lt;a href=&quot;https://www.npr.org/sections/parallels/2017/11/25/564098130/protecting-the-netherlands-vulnerable-coasts-with-a-sand-motor&quot; rel=&quot;nofollow noreferrer&quot;&gt;Protecting The Netherlands' Vulnerable Coasts With A 'Sand Motor'&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Zandmotor YouTube: &lt;a href=&quot;https://youtu.be/m1H-58W7QDk&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Sand Motor Five years of Building with Nature&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;ecoshape.org: &lt;a href=&quot;https://www.ecoshape.org/en/projects/the-delfland-sand-engine/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sand Motor Delfland Coast&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;dezandmotor.nl &lt;a href=&quot;http://www.dezandmotor.nl/en/the-sand-motor/introduction/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Introduction&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Wikipedia &lt;a href=&quot;https://en.wikipedia.org/wiki/Sand_engine&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sand Engine&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;but I'm still not getting what this is for. Is this a &quot;natural&quot; way to form long-lasting sand dunes on the coast, or something more, or different?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it possible to summarize the primary goal of this project? What exactly is the desired outcome, or success criteria?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2017-11-27T00:17:22.277" Title="What is a Sand Motor &quot;for&quot;?" Tags="|geoengineering|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12754" PostTypeId="1" CreationDate="2017-11-26T21:47:20.417" Score="3" ViewCount="201" Body="&lt;p&gt;In &quot;20,000 Leagues Under the Sea&quot; by Jules Verne there is a reference to a &quot;tempest&quot; that destroyed Yeddo (Tokyo) in Japan:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;They are they which, in the tempest of December 23, 1864, after&#xA;  destroying the town of Yeddo, in Japan, broke the same day on the&#xA;  shores of America.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Was this a real event or just fiction?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2017-12-28T01:51:44.757" Title="Typhoon in December of 1864 in Japan?" Tags="|tropical-cyclone|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12755" PostTypeId="2" ParentId="12753" CreationDate="2017-11-27T00:17:22.277" Score="2" Body="&lt;p&gt;From the material presented, it appears the southern coast of the Netherlands is subject to coastal erosion which requires the importation of sand to restore the coastal profile and maintain sand dunes that ensure the integrity of the coast.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Previously, sand was imported every five years and deposited along the coast by mechanized equipment, in a series of restoration campaigns. This is a very disruptive process for natural systems and the humans along that part of the coast.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sand motor is an artificial, sacrificial peninsular of sand that will be redistributed along the coast, continually replenishing the sand lost to erosion. The slower and continuous redistribution of sand, but natural forces will allow for a consolidation of the coastal sand dunes in a seemingly natural manner that is not disruptive like the previous replenishment campaigns conducted every five years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The continuous slow replenishment of coastal sand, also allows flora to naturally establish itself and colonize the sand dunes. Their roots acting as a mesh to hold sand, thus reinforcing the sand dunes in a natural and non-disruptive manner.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The project is aiming to produce a more natural way to producing long lasting sand dunes to protect the integrity of the coast.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-11-27T00:17:22.277" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12756" PostTypeId="1" CreationDate="2017-11-27T05:44:24.830" Score="2" ViewCount="1036" Body="&lt;p&gt;Why are winters along the North American Atlantic northeast coast colder than winters along the North American Pacific Northwest coast? &lt;/p&gt;&#xA;" OwnerUserId="11570" LastEditorUserId="2536" LastEditDate="2017-12-01T11:46:21.267" LastActivityDate="2017-12-01T11:46:21.267" Title="Colder winters along the North American Atlantic northeast" Tags="|meteorology|climate|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="12757" PostTypeId="1" CreationDate="2017-11-27T06:23:17.257" Score="2" ViewCount="212" Body="&lt;p&gt;I’ve recently been very interested in globe-trotting via Google Earth. At first I was using it to plan out hikes to possible mineral deposits locally, or potential fossils/ archeology sites. However I soon became sidetracked in &lt;a href=&quot;https://en.wikipedia.org/wiki/Tombouctou_Region&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Tombouctou Region of Mali&lt;/a&gt;. I stumbled across an outcrop of rock in the middle of the desert. It appears to be brilliant blue.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am wondering if this is some kind of satellite imagery to detect heat or moisture? Or is this the actual colour of rock/mineral?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AZXxV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AZXxV.jpg&quot; alt=&quot;First image&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/f2XqG.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/f2XqG.jpg&quot; alt=&quot;Second image&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ps6t9.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ps6t9.jpg&quot; alt=&quot;Third image&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11565" LastEditorUserId="6298" LastEditorDisplayName="user12525" LastEditDate="2022-02-06T17:23:40.193" LastActivityDate="2022-02-06T17:23:40.193" Title="What are these features in the Tombouctou Region?" Tags="|geology|mineralogy|satellites|desert|satellite-oddities|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="12759" PostTypeId="2" ParentId="12756" CreationDate="2017-11-27T19:32:22.647" Score="-1" Body="&lt;p&gt;Winters are colder on the &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Atlantic_Northeast&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atlantic northeast coast&lt;/a&gt; partly due to a slight difference in longitude/latitude of Newfoundland is 53.1355’N - 57.6604’W as opposed to say Vancouver British Columbia on The &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Pacific_Northwest&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pacific NorthWest&lt;/a&gt;. 49.2827’N - 123.1207’W. the distance from the equator is greater.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second and more profound part of this answer; has to do with weather patterns, Wind directions, high/low pressure systems, warm/cold fronts. Jet streams.&#xA;Prevailing winds produced by &lt;a href=&quot;https://i.stack.imgur.com/d38RK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;ocean temps&lt;/a&gt; and currents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To be more specific the North East coast of Canada expirences low pressure systems barring down from the Canadian north as you can see in the “wind speed model I have provided. Commonly reffered to as an “ nor-easter” fisher men slang for trouble.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The west coast experiences a tropical jet stream called the &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Pineapple_Express&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pineapple Express&lt;/a&gt;. This bring with it warm moist air and lots of precipitation&#xA;Please find attached a currents wind direction graph.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kind Reguards&#xA;Jeff B.&lt;a href=&quot;https://i.stack.imgur.com/64azS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/64azS.jpg&quot; alt=&quot;GSF MODEL ANALIYSIS&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.m.wikipedia.org/wiki/Pacific_Northwest&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pacific NorthWest &lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.m.wikipedia.org/wiki/Atlantic_Northeast&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atlantic northeast coast&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/d38RK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/d38RK.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.m.wikipedia.org/wiki/Pineapple_Express&quot; rel=&quot;nofollow noreferrer&quot;&gt;enter link description here&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11565" LastEditorUserId="11565" LastEditDate="2017-11-29T08:04:36.070" LastActivityDate="2017-11-29T08:04:36.070" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12761" PostTypeId="2" ParentId="12746" CreationDate="2017-11-28T00:12:45.347" Score="2" Body="&lt;p&gt;&lt;a href=&quot;http://infohost.nmt.edu/~petro/faculty/Nguyen/PE413/Presentation/C1/2_FracturePressure.ppt&quot; rel=&quot;nofollow noreferrer&quot;&gt;fracture formula&lt;/a&gt; What is the method of injection and fluid you are using? Apply a leak off test to the formation after drilling out casing shoe and your 5-10m into open hole. I’ve attached two links that may be helpful.                           &lt;a href=&quot;http://publications.jrc.ec.europa.eu/repository/bitstream/111111111/30129/1/an%20overview%20of%20hydraulic%20fracturing%20and%20other%20stimulation%20technologies%20%282%29.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;formation fracture pressure&lt;/a&gt;&#xA;                         &lt;a href=&quot;http://publications.jrc.ec.europa.eu/repository/bitstream/111111111/30129/1/an%20overview%20of%20hydraulic%20fracturing%20and%20other%20stimulation%20technologies%20%282%29.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;a list of methods&lt;/a&gt;&#xA;There are also plenty of apps for you’re phone that you may find useful. Search “drilling formulas”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basic frac graduent is 18kpa per meter there fore at 1000m it would take 18000kpa pressure  more or less to fracture a zone.&#xA;In psi it is .8 psi per ft of vertical depth.&#xA;Usually it takes a higher pressure to frac a formation but feed rates are much lower.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kind regards&#xA;Jeff B.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yzfQS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yzfQS.jpg&quot; alt=&quot;http://infohost.nmt.edu/~petro/faculty/Nguyen/PE413/Presentation/C1/2_FracturePressure.ppt][2]&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11565" LastEditorUserId="11565" LastEditDate="2017-11-28T02:08:33.930" LastActivityDate="2017-11-28T02:08:33.930" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12763" PostTypeId="1" CreationDate="2017-11-28T02:52:58.390" Score="0" ViewCount="122" Body="&lt;p&gt;I found this image of a bird with another image below its right wing on google earth in nazca peru. Is there any maps or infomation available that can help me identify this one?&lt;a href=&quot;https://i.stack.imgur.com/wZVDj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wZVDj.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kind regards&#xA;Jeff B.&lt;/p&gt;&#xA;" OwnerUserId="11565" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T14:12:57.353" LastActivityDate="2019-08-29T14:12:57.353" Title="Can someone provide a map of Nazca lines with this image in it?" Tags="|earth-history|earth-observation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12764" PostTypeId="2" ParentId="10766" CreationDate="2017-11-28T08:03:35.150" Score="1" Body="&lt;p&gt;From my personal experience there is two types of coring. 1st being conventional coring. &lt;a href=&quot;http://www.slb.com/-/media/Files/resources/oilfield_review/ors15/spr15/define-coreMatter.pdf?la=en&amp;amp;hash=08992E249F75DB62A99F41E6EE85895B6AFCDF1D&quot; rel=&quot;nofollow noreferrer&quot;&gt;Conventional coring&lt;/a&gt;is preformed using third party cutting tools as (BHA) bottom hole assembly.  This consists of a &lt;a href=&quot;https://i.stack.imgur.com/7HKen.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;rotating cutting head&lt;/a&gt; made up of tungsten carbide/diamond. The core barrel sits on top of cutting bit than is fasten by an x/o (cross over), to the drill string and Kelly or top drive (rig specific).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This (bha) equipment is delicate as far as rig equipment goes. Special attention is required while cutting and retrieving core. Torque, weight, pump pressure (if required), rotary speed among other things must all be monitored closely. Once the core is cut. It is delicately fasten inside the barrel with a series of little metal prongs in a circular pattern.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A trip speed is required as to not damage or shake the core out. Trip speed is time it takes to lay out (dp) drill pipe. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;2nd method is wire line retrieval. This uses a Logging truck with gamma tools that log data and X-ray the intended zones. This system requires a &lt;a href=&quot;https://i.stack.imgur.com/Q7hqn.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;gun barrel system&lt;/a&gt; on the end of a wireline. The drilling rigs purpose is basically just a plat form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is just a very basic description from my personal experience. Feel free to ask more.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I’ve provided some examples of bits &amp;amp; barrels as well links with detailed descriptions of both processes.     &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.slb.com/news/inside_news/2015/2015_0612_defining_coring.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;Schlumberger‘s coring methods&amp;amp;tools&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11565" LastEditorUserId="2958" LastEditDate="2017-11-28T12:58:31.850" LastActivityDate="2017-11-28T12:58:31.850" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12765" PostTypeId="1" CreationDate="2017-11-28T11:54:05.183" Score="2" ViewCount="222" Body="&lt;p&gt;I am developing a remote sensing model and I also want to consider the climate data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is, how can I define a dry/wet season for a country like e.g. Austria?&lt;br /&gt;&#xA;I have the weather data for three years and I would like to separate the dates into dry and wet.&lt;/p&gt;&#xA;" OwnerUserId="11585" LastEditorUserId="595" LastEditDate="2017-11-29T10:51:03.133" LastActivityDate="2018-01-20T09:20:50.290" Title="Defining dry/wet season in Europe" Tags="|climate|seasons|" AnswerCount="1" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="12766" PostTypeId="1" AcceptedAnswerId="12776" CreationDate="2017-11-28T16:26:11.510" Score="-1" ViewCount="153" Body="&lt;p&gt;Just wondering with the latest satellites currently available, is it possible to locate gold which is buried under 200 ft? what is the maximum depth that satellites can look for such minerals. &lt;/p&gt;&#xA;" OwnerUserId="11586" LastEditorUserId="11586" LastEditDate="2017-11-29T11:22:12.410" LastActivityDate="2017-11-29T11:22:12.410" Title="Satellites minerals finding capability" Tags="|minerals|satellites|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="12767" PostTypeId="1" CreationDate="2017-11-28T19:05:02.150" Score="2" ViewCount="132" Body="&lt;p&gt;Is there any likelihood that an earthquake could trigger a volcanic event?  I'm thinking that because the Pacific tectonic plate nearly coincides with the &quot;ring-of-fire,&quot; particularly along the west coast of the US, that there could a causal relationship between the two events. &lt;/p&gt;&#xA;" OwnerUserId="11587" LastActivityDate="2017-11-28T19:05:02.150" Title="Possibility of Domino Effect" Tags="|earthquakes|volcanology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12768" PostTypeId="5" CreationDate="2017-11-28T20:50:21.977" Score="0" Body="&lt;p&gt;For questions about the &lt;a href=&quot;https://en.wikipedia.org/wiki/Petroleum&quot; rel=&quot;nofollow noreferrer&quot;&gt;origin&lt;/a&gt;, &lt;a href=&quot;https://i.stack.imgur.com/6YCH7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;history &amp;amp; methods of production&lt;/a&gt; of petroleum; e.g. application and development of petroleum based products &amp;amp; other usages, or evolution of petroleum technology in the past, present &amp;amp; future from the &lt;a href=&quot;https://csegrecorder.com/articles/view/ancient-chinese-drilling&quot; rel=&quot;nofollow noreferrer&quot;&gt;ancient Chinese method&lt;/a&gt; to today.&lt;/p&gt;&#xA;" OwnerUserId="11565" LastEditorUserId="2958" LastEditDate="2022-05-16T03:57:09.193" LastActivityDate="2022-05-16T03:57:09.193" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="12769" PostTypeId="4" CreationDate="2017-11-28T20:50:21.977" Score="0" Body="For questions about the origin, history &amp; methods of production of petroleum; e.g. application and development of petroleum based products &amp; other usages, or evolution of petroleum technology in the past, present &amp; future from the ancient Chinese method to today." OwnerUserId="11565" LastEditorUserId="2958" LastEditDate="2022-05-16T03:56:14.143" LastActivityDate="2022-05-16T03:56:14.143" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="12770" PostTypeId="2" ParentId="12756" CreationDate="2017-11-28T21:57:43.677" Score="3" Body="&lt;p&gt;As air moves over the surface of the earth, the properties of the surface (such as temperature) can alter the air. Since at those particular latitudes, the predominant wind direction is from the west and partially the north, it is important to note what is north and west of both locations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;West of the northeast Atlantic is land, and northwest is Canada. This means that the air is drier, and prone to have characteristics of mimicking continental- polar (&lt;a href=&quot;http://www.theweatherprediction.com/habyhints/89/&quot; rel=&quot;nofollow noreferrer&quot;&gt;cP&lt;/a&gt;) air. Continental polar air tends to be dry (since it is over land) and cold (since it is coming from an area that receives less sunlight).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;West of the northwest pacific is the Pacific Ocean, and northwest is still the Pacific Ocean. This means that the air is more moist and prone to have characteristics mimicking the air over the ocean, called Maritime polar (&lt;a href=&quot;http://www.theweatherprediction.com/habyhints/87/&quot; rel=&quot;nofollow noreferrer&quot;&gt;mP&lt;/a&gt;). Since the water tends to warm slower than the land and also slower than the land, the air over the water is usually warmer during the winter and cooler over the summer than the air over the land. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To summarize:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;At those latitudes, the wind usually blows from the north and west.&lt;/li&gt;&#xA;&lt;li&gt;During the winter, air over the ocean is warmer than air over land.&lt;/li&gt;&#xA;&lt;li&gt;North and West of the Northwest coast is the Pacific ocean, while land is west of the Atlantic coast.&lt;/li&gt;&#xA;&lt;li&gt;Therefore, the winter in the northwest coast is usually warmer than the winter along the northeast coast.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-11-28T21:57:43.677" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12771" PostTypeId="1" AcceptedAnswerId="12773" CreationDate="2017-11-29T00:56:52.107" Score="2" ViewCount="256" Body="&lt;p&gt;I'm not sure if I can ask this question here but it is the only Stack Exchange community where I saw the tag Geography. I was reading about the great Buenos Aires and I saw this night satellital picture. There is this big area apparently unpopulated or with little population surrounded by the metropolis. What is it? Why is it apparently unpopulated?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5DlaU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5DlaU.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="9635" LastActivityDate="2017-11-29T03:57:22.827" Title="Why is this area apparently unpopulated in the great Buenos Aires, what is it?" Tags="|geography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12773" PostTypeId="2" ParentId="12771" CreationDate="2017-11-29T03:57:22.827" Score="5" Body="&lt;p&gt;“&lt;a href=&quot;https://i.stack.imgur.com/E2g9G.jpg&quot; rel=&quot;noreferrer&quot;&gt;Campo de Mayo&lt;/a&gt; is a military base located in Greater Buenos Aires, Argentina, 30 km (19 mi) northwest of Buenos Aires”. &#xA;                                              &lt;a href=&quot;https://i.stack.imgur.com/E2g9G.jpg&quot; rel=&quot;noreferrer&quot;&gt; Wikipedia&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/E2g9G.jpg&quot; rel=&quot;noreferrer&quot;&gt;wikipedia&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/E2g9G.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/E2g9G.jpg&quot; alt=&quot;Campo de mayo&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11565" LastActivityDate="2017-11-29T03:57:22.827" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12774" PostTypeId="1" AcceptedAnswerId="12780" CreationDate="2017-11-29T06:24:13.843" Score="3" ViewCount="1657" Body="&lt;p&gt;Radioactive rocks can release a gas called radon when they decay, which can build up in the basements of buildings with serious effects on people's health. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anybody have information on how radon is produce naturally in nature? How do these rock’s become radioactively charged? &#xA;Are these rocks common? Pictures or examples?&lt;/p&gt;&#xA;" OwnerUserId="11565" LastEditorUserId="543" LastEditDate="2017-11-30T22:15:45.790" LastActivityDate="2017-11-30T22:15:45.790" Title="Radon is a naturally occurring radioactive gas. How does this work?" Tags="|geology|atmosphere|rocks|natural-conditions|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12775" PostTypeId="2" ParentId="8048" CreationDate="2017-11-29T06:55:46.053" Score="2" Body="&lt;p&gt;Answer to this question is very well given at &lt;a href=&quot;https://physics.stackexchange.com/questions/15184/why-is-moonlight-less-colourful-than-yellow-light?&quot;&gt;Physics forum&lt;/a&gt; pointed out by @gerrit. In short, Light should be strong enough in order to notice its colour by human eyes. Even on full moon night, light from the moon is 10 times less luminous than the dark limit of civil twilight hence we don't perceive sky color or even moon colour like we do during the day.  &lt;/p&gt;&#xA;" OwnerUserId="10780" LastActivityDate="2017-11-29T06:55:46.053" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12776" PostTypeId="2" ParentId="12766" CreationDate="2017-11-29T07:46:39.630" Score="2" Body="&lt;p&gt;Assuming a well has a diameter of 2 metres, even 5 metres. This would be an exceedingly small target area for a satellite, some hundreds to thousands of kilometres above the Earth to find. Being buried, particularly at 200 metres depth, increases the difficulty exponentially.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Satellites are better at finding minerals on the surface, or just below the surface, not at 200 metres depth.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-11-29T07:46:39.630" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12777" PostTypeId="2" ParentId="12774" CreationDate="2017-11-29T11:14:54.547" Score="5" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Radon&quot; rel=&quot;noreferrer&quot;&gt;Radon&lt;/a&gt;, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;occurs naturally as an intermediate step in the normal radioactive decay chains through which thorium and uranium slowly decay into lead; radon itself is a decay product of radium.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Some &lt;a href=&quot;https://en.wikipedia.org/wiki/Granite&quot; rel=&quot;noreferrer&quot;&gt;granite&lt;/a&gt; deposits contain small amounts of uranium. As the uranium undergoes natural radioactive decay radon is produced.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In areas where granite underlies buildings, particularly if the granite is near the surface of the Earth, radon can accumulate in basements of buildings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some underground water sources can also contain radon, particularly if they are near granite. As the ground water moves through soil, radon can be released into the soil and thus it can enter basements.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-11-29T11:14:54.547" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12779" PostTypeId="2" ParentId="12763" CreationDate="2017-11-29T16:34:27.337" Score="1" Body="&lt;p&gt;&lt;a href=&quot;http://www.go2peru.com/peru_guide/nazca/map_nazca_lines.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;go2peru&lt;/a&gt;  has a nice set of maps of the Nazca area.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2017-11-29T16:34:27.337" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12780" PostTypeId="2" ParentId="12774" CreationDate="2017-11-29T16:56:07.443" Score="6" Body="&lt;p&gt;Radon (&lt;a href=&quot;https://www.webelements.com/radon/isotopes.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;more specifically Radon-222&lt;/a&gt;) is produced in the decay chain of Uranium-238.   Radon-223 is also produced by the decay chain of Uranium-235 and Radon-220 is produced by the decay chain of Thorium-232 but both Radon-223 and Radon-220 have half-lives of less than a minute, so they almost never reach the atmosphere where they can be breathed in because they mostly form underground and they decay too quickly to reach the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Radon is unusual in that it's the only noble gas along the 4 primary decay chains and only the Uranium to Lead chain produces Radon-222 which has half life long enough to reach the atmosphere and get breathed in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Decay_chain&quot; rel=&quot;nofollow noreferrer&quot;&gt;More on decay chains here&lt;/a&gt; &lt;a href=&quot;http://metadata.berkeley.edu/nuclear-forensics/Decay%20Chains.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;and here&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Uranium-238 has half life of about 4.5 billion years, so about half the Uranium-238 that was present when the Earth formed is still here.  It decays very slowly, which is why it's not dangerous to be around Uranium in it's natural form.  (though if somebody hands you a block of it, you might still want to wash your hands after touching it - then call national security) . . . but I digress.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Radon-222 has a very short half life of 3.8 days, so while the Uranium that produces it decays very slowly, the Radon is highly radioactive and it decays (into other radioactive elements) quite rapidly.   If you had a sample of Radon-222 for example, in less than a month, 99% of your sample would be gone.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because it forms slowly and decays quickly it never collects beyond a very trace concentration and it continuously needs to be regenerated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Houses with a Radon problem need to be continuously ventilated because of that regeneration.  &lt;em&gt;At least/about two or three times a day I would think (see comment directly below, once a day may be sufficient)&lt;/em&gt;, but it's worth pointing out that the Radon in houses is so faint that it takes months, if not years, for any kind of health problems to arise.   It's kind of a weird thing.  It's not dangerous at all to walk through a house with unsafe Radon levels, similar to how it's not dangerous to &lt;a href=&quot;https://www.tripadvisor.com/Attraction_Review-g294474-d3370334-Reviews-CHERNOBYL_TOUR-Kiev.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;visit Chernobyl&lt;/a&gt;.   It's just not a good idea to live there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Radon is also likely to only be a problem in poorly ventilated houses, (basement's especially, because the heavy gas tends to settle) but a good ventilation system should make any house safe.  And it's more common &lt;a href=&quot;https://geopub.epa.gov/Radon/&quot; rel=&quot;nofollow noreferrer&quot;&gt;in specific areas&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's the problem of keeping the house warm in winter and maintaining ventilation, because ventilation does need to be maintained.  Houses can be also built above ground to reduce exposure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a general rule, it's the ingestion, either breathing or swallowing of radioactive material that's most dangerous.  That's why it's a good idea to put on a gas mask to prevent breathing in any radioactive dust or fallout (though a gas mask won't keep gas like Radon out).   And it's a good idea to leave your clothes in a separate changing room and shower thoroughly if exposed or walking through radioactive fallout - that has nothing to do with your question, just putting it out there.   Also the opposite applies if there's radiation outside from a nuclear accident or bomb- close all windows and try to keep ventilation as close to zero as possible, at least for a day or so until you get instruction on the levels, but . . . I digress.   Point is, because Radon is easily breathed in, it's quite toxic even in very small amounts.   At the same time, the Radon concentration inside houses with a radon problem is so small, that it still takes months if not years of exposure to lead to problems.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's why Geiger-counters aren't used to test for Radon.  There's too little radiation.  You need specific Radon detectors.   &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Are these rocks common?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes, and no.   Because the gas comes from Uranium, (and mostly from underground), Uranium isn't exactly common but it's not super-rare either.  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How do these rock’s become radioactively charged?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This was covered above, but Uranium, in small amounts, is in lots of different places.   The Rocks were always (mildly) radioactive.  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Pictures or examples?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;To my knowledge, pictures or examples don't do any good because trace amounts of Uranium in rocks doesn't look any different.  Besides, most of the Uranium is underground.   You have to rely on Radon testing and look at locations where Radon is more of a problem.   If you live and work above the first floor, and not near a mine or massive dig-site, you probably have little to worry about.   If you live in a basement, you should have it checked out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the process&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Uranium or U-238 goes through several steps in it's decay and this chain is only the most common outcome.  Part of the problem with Radon, is if you breath it in, and don't breath it out, it becomes Polonium and goes through a few other steps.  In high enough concentration, Radon is extremely toxic.  From rocks, the concentration that's likely to form in a house is usually low enough that harmful exposure takes months or years.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Jr6x1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Jr6x1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2017-11-30T13:31:39.187" LastActivityDate="2017-11-30T13:31:39.187" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12782" PostTypeId="2" ParentId="12388" CreationDate="2017-11-30T02:55:43.517" Score="2" Body="&lt;p&gt;MetEd from NCAR has a good &lt;a href=&quot;https://sites.google.com/a/ucar.edu/model-encyclo-determ/&quot; rel=&quot;nofollow noreferrer&quot;&gt;encyclopedia of models&lt;/a&gt; that summarizes some weather models. Of course, when models update, such as the GFS dynamical core being converted to the FV3, or changes in data assimilation systems, they may not be up-to-date. This also doesn't have ALL weather models, but some of the more common ones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, there are models missing from the encyclopedia, such as the SREF, GEFS, the JMA model, the Panasonic weather model, any iteration of the WRF model, statistical post-processed models, etc.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-11-30T02:55:43.517" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12783" PostTypeId="1" CreationDate="2017-11-30T06:57:34.107" Score="0" ViewCount="67" Body="&lt;p&gt;Theorist speculate on the dozens of loud &lt;a href=&quot;https://www.google.ca/amp/s/www.mnn.com/earth-matters/climate-weather/stories/amp/mysterious-loud-booms-are-being-heard-around-world-and-no-one-knows-why&quot; rel=&quot;nofollow noreferrer&quot;&gt;atmospheric booms&lt;/a&gt; across globe.  Has any recognized institutions offered a plausible explanation as of now? &lt;/p&gt;&#xA;" OwnerUserId="11565" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T11:57:47.660" LastActivityDate="2019-08-29T11:57:47.660" Title="Theorist speculate about dozens of loud atmospheric booms across globe" Tags="|meteorology|atmosphere|seismic|air-currents|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12784" PostTypeId="1" CreationDate="2017-11-30T17:20:57.540" Score="3" ViewCount="98" Body="&lt;p&gt;In his famous paper &lt;a href=&quot;https://www.colorado.edu/geolsci/courses/GEOL5700-9/pdf/Fall07/Patterson.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Age of meteorites and the earth&lt;/em&gt;&lt;/a&gt; (1956), Patterson uses the following expressions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xfg6T.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xfg6T.jpg&quot; alt=&quot;geochrone equations&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which I assume are the same as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$  \left(\frac{Pb^{206}}{Pb^{204}}\right)_P = \left(\frac{Pb^{206}}{Pb^{204}}\right)_I + \left({e^{\lambda_{238}T}-1}\right)\cdot\left(\frac{U^{238}}{Pb^{204}}\right)_P \tag{1}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$  \left(\frac{Pb^{207}}{Pb^{204}}\right)_P = \left(\frac{Pb^{207}}{Pb^{204}}\right)_I + \frac{{e^{\lambda_{235}T}-1}}{\left(\frac{U^{238}}{U^{235}}\right)_P}\cdot\left(\frac{U^{238}}{Pb^{204}}\right)_P \tag{2}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;He describes how the Canyon Diablo meteorite had such a small $U^{238}/Pb^{204}$ ratio ($0.025$) that &quot;no observable change in the isotopic composition of lead could have resulted from radioactive decay after the meteorite was formed&quot;. Then he concludes that the meteorite's lead is representative of the isotopic composition of primordial lead at the time meteorites were formed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My first issue with this is that we already have all the values necessary to determine the parameters in his expressions without assuming that the primordial lead isotopic composition was similar to that of the Canyon Diablo meteorite:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\begin{array}&amp;amp;&#xA;\left(\frac{Pb^{206}}{Pb^{204}}\right)_{P,\text{ Canyon Diablo}} &amp;amp;= 9.46\\&#xA;\left(\frac{Pb^{207}}{Pb^{204}}\right)_{P,\text{ Canyon Diablo}} &amp;amp;= 10.34\\&#xA;\left(\frac{U^{238}}{Pb^{204}}\right)_{P,\text{ Canyon Diablo}} &amp;amp;= 0.025&#xA;\end{array}$$&#xA;$$\left(\frac{U^{238}}{U^{235}}\right)_P = 137.8$$&#xA;$$\begin{array}&amp;amp;&#xA;\lambda_{238} &amp;amp;= 1.537\times 10^{-10}\text{ yr}^{-1}\\&#xA;\lambda_{235} &amp;amp;= 9.72\times 10^{-10}\text{ yr}^{-1}\\&#xA;\end{array}$$&#xA;$$T = 4.55\times 10^9\text{ yr}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plugging those values into equations $(1)$ and $(2)$ and solving for $\left(Pb^{206}/Pb^{204}\right)_I$ and $\left(Pb^{207}/Pb^{204}\right)_I$, we arrive at:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$  \left(\frac{Pb^{206}}{Pb^{204}}\right)_P = 9.43 + 1.012\left(\frac{U^{238}}{Pb^{204}}\right)_P \tag{3}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$  \left(\frac{Pb^{207}}{Pb^{204}}\right)_P = 10.33 + 0.597\left(\frac{U^{238}}{Pb^{204}}\right)_P \tag{4}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, the parameters are very similar to those in Patterson's expressions, but not exactly the same. The second problem is that directly substituting the approximate values below also doesn't work:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\begin{array}&amp;amp;&#xA;\left(\frac{Pb^{206}}{Pb^{204}}\right)_I \approx \left(\frac{Pb^{206}}{Pb^{204}}\right)_{P,\text{ Canyon Diablo}} &amp;amp;= 9.46\\&#xA;\left(\frac{Pb^{207}}{Pb^{204}}\right)_I \approx \left(\frac{Pb^{207}}{Pb^{204}}\right)_{P,\text{ Canyon Diablo}} &amp;amp;= 10.34\\&#xA;\end{array}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So how exactly did he arrive at the parameters $9.50$, $1.014$, $10.36$, and $0.601$?&lt;/p&gt;&#xA;" OwnerUserId="11611" LastActivityDate="2017-11-30T17:20:57.540" Title="How exactly did Patterson determine the parameters in his Pb–Pb geochron equations?" Tags="|geochronology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12786" PostTypeId="1" CreationDate="2017-11-30T18:41:51.220" Score="3" ViewCount="319" Body="&lt;p&gt;I was told that &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Seismic moment is determined by the observed spectral levels of the receiving waves.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But I don't quite understand what it means.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How is this done in practice? Do you need anything in addition to a seismogram to infer the seismic moment value (like elastic material parameters)?&lt;/p&gt;&#xA;" OwnerUserId="5748" LastActivityDate="2017-11-30T18:41:51.220" Title="How to calculate seismic moment from seismograms?" Tags="|geophysics|earthquakes|seismology|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12787" PostTypeId="1" CreationDate="2017-11-30T21:40:40.347" Score="0" ViewCount="543" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/mEpfz.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pOZ9f.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/c2Q82.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8hRUS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DS5KR.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don’t know much about gems so I tried to upload pictures in different lighting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The corundum pic&#xA;Pictured with it was scratched by this stone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can’t tell if the corundum scratches this stone.  It doesn’t look like it to me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It was found in the Deposit Dan active volcano.&lt;/p&gt;&#xA;" OwnerUserId="11321" LastActivityDate="2017-12-01T12:10:52.950" Title="What stone is this?" Tags="|geology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12788" PostTypeId="1" CreationDate="2017-11-30T22:44:30.587" Score="1" ViewCount="510" Body="&lt;p&gt;If I have a mineral in which I did a SEM analysis on and got the data (elements and their wt% with  Std. Dev., MDL, atomic % oxide % and k ratio) how would I go about quantifying the sample's composition? I know I would need standards to do so but I not sure how to go about this. Can someone please assist? Thank you!&lt;/p&gt;&#xA;" OwnerUserId="11640" LastEditorUserId="725" LastEditDate="2017-12-04T03:41:32.847" LastActivityDate="2017-12-04T04:34:21.453" Title="Analyzing composition of a mineral using SEM" Tags="|geology|geochemistry|mineralogy|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12789" PostTypeId="2" ParentId="12787" CreationDate="2017-11-30T23:38:03.137" Score="3" Body="&lt;p&gt;I believe it’s a portion on an &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Amethyst&quot; rel=&quot;nofollow noreferrer&quot;&gt;amethyst geode.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.m.wikipedia.org/wiki/Amethyst&quot; rel=&quot;nofollow noreferrer&quot;&gt;amethyst geode&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11565" LastEditorUserId="11565" LastEditDate="2017-12-01T00:00:53.897" LastActivityDate="2017-12-01T00:00:53.897" CommentCount="2" CommunityOwnedDate="2017-12-01T00:00:53.897" ContentLicense="CC BY-SA 3.0" />
  <row Id="12791" PostTypeId="1" CreationDate="2017-12-01T04:09:25.760" Score="1" ViewCount="891" Body="&lt;p&gt;The polar &lt;a href=&quot;http://www.bbc.com/news/science-environment-19496674&quot; rel=&quot;nofollow noreferrer&quot;&gt;ice caps&lt;/a&gt; are melting at a significant rate partly due to the albedo effect, releasing greenhouse gas-methane into earth’s atmosphere. At the same time we are logging our forests for agricultural expansion. Is year twenty -thirty an accurate prediction for polar ice extinction?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A.)  Is there a model to show just how much our forests absorbs green house gases? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;B.)  Will an abundance of $CO_2$ &amp;amp; methane-gas over load the earths forests &amp;amp; oceans natural ability absorb such gases and start to kill them off.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;C.)  Does our ocean's plankton act as a mechanism to recycle the atmospheres $CO_2$ Green house gases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.bbc.com/news/science-environment-19496674&quot; rel=&quot;nofollow noreferrer&quot;&gt;BBC Artical $CO_2$&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11565" LastEditorUserId="11908" LastEditDate="2019-03-13T05:12:59.177" LastActivityDate="2019-03-13T05:12:59.177" Title="Polar Ice caps are melting? Questions on enviromental impact" Tags="|atmosphere|climate-change|climate|glaciology|carbon-cycle|" AnswerCount="2" CommentCount="5" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12792" PostTypeId="1" AcceptedAnswerId="12798" CreationDate="2017-12-01T09:16:25.433" Score="2" ViewCount="244" Body="&lt;p&gt;Glyphosate is the most important herbicide in agriculture by quantity. A committee of the European Union just recently &lt;a href=&quot;https://www.theguardian.com/environment/2017/nov/27/controversial-glyphosate-weedkiller-wins-new-five-year-lease-in-europe&quot; rel=&quot;nofollow noreferrer&quot;&gt;voted&lt;/a&gt; against a ban of the substance, after much debate around possible negative effects on human health. I now see a lot of petitions popping up on social media, calling for an immediate ban. This got me wondering: if Glyphosate would be banned in the near future, say in the course of next year, what problems would arise for farmers? Are there viable alternative weed killers, and would productivity be significantly reduced without using one?&lt;/p&gt;&#xA;" OwnerUserId="11650" LastEditorUserId="11650" LastEditDate="2017-12-02T18:12:18.633" LastActivityDate="2017-12-04T19:26:37.240" Title="How much does the productivity of modern agriculture depend on Glyphosate?" Tags="|environmental-protection|agriculture|" AnswerCount="1" CommentCount="16" ContentLicense="CC BY-SA 3.0" />
  <row Id="12793" PostTypeId="1" CreationDate="2017-12-01T11:03:09.443" Score="0" ViewCount="78" Body="&lt;p&gt;Many of us drive a car, trucks get driven each day and many other machines use gasoline as well. This gets pumped out of our earth continuously, making earth bit by bit more hallow. Not a real calculation, but seeing how many trucks I see just in my small country (The Netherlands) and extrapolate to the whole earth times the average gasoline usage per hour.. we should be thinking about small cities in cubic meters per day of gasoline usage. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That made me wondering.. What is the number a bit more exact? And could you give a relative estimate to compare that number to (like a football stadium).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;I don't care for an error margin of 5% or numbers from 2013. Just want something to 'grab' and get an idea.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="11653" LastActivityDate="2017-12-01T13:52:26.550" Title="How much gasoline in cubic meters is used per day?" Tags="|gas|" AnswerCount="1" CommentCount="1" ClosedDate="2017-12-02T23:58:37.107" ContentLicense="CC BY-SA 3.0" />
  <row Id="12794" PostTypeId="2" ParentId="12787" CreationDate="2017-12-01T12:10:52.950" Score="0" Body="&lt;p&gt;You may want to take a look at fluorite.  What's throwing me off is that you say this specimen scratches corundum?  Corundum is a 9 on the Mohs scale and fluorite is only a 4.  If you are unsure of this you could try scratching this rock with a steel pocket knife.  Since the steel knife is ~6 on the hardness scale it should scratch this rock if it's fluorite.  If not you can rule out fluorite.  Additionally, fluorite fluoresces (glows) under uv (black light).  &lt;a href=&quot;http://www4.uwm.edu/course/geosci-100/Mineral_Rocks/fluorite_data.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; is a link to more information on fluorite and the source of the image below. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xzWv6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xzWv6.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2017-12-01T12:10:52.950" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12795" PostTypeId="2" ParentId="12793" CreationDate="2017-12-01T13:46:32.973" Score="2" Body="&lt;p&gt;The total consumption of crude oil according to this &lt;a href=&quot;http://www.indexmundi.com/energy/&quot; rel=&quot;nofollow noreferrer&quot;&gt;site&lt;/a&gt; is around 100 000 000 barrels per day and is in SI units 10 000 000 cubic meters. Of course not all of that can be processed to gasoline, but the scale of things is revealed. That would be actually bigger than a football stadium's volume a day as it would effectively be a cube with all sides around 215 meters.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastEditorUserId="6465" LastEditDate="2017-12-01T13:52:26.550" LastActivityDate="2017-12-01T13:52:26.550" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12796" PostTypeId="2" ParentId="12791" CreationDate="2017-12-01T18:02:10.103" Score="3" Body="&lt;p&gt;I think you misinterpret the article you cited. In the article it is stated that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The melting of the polar ice-caps has&#xA;  an effect &quot;the equivalent of about 20 years of additional CO$_2$ being&#xA;  added by man&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is due to the energy in sunlight which is no longer reflected by the white ice and snow of the polar caps. This energy will be partly absorbed by the darker surface of the ocean or land which will be underneath the ice-caps. This absorption of energy (instead of reflection) has an effect which is equal to &quot;the equivalent of about 20 years if additional CO$_2$ being added by mankind&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There probably are models that can tell how much CO$_2$ can be absorbed by trees. However, an ecosystem which is in balance (e.g. a full grown forest) doesn't absorb that much CO$_2$ anymore. This is because the growth of new trees is equal to the dying and decomposition of old trees (in balance). Only a little part might be stored in the soil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An increase of CO$_2$ might increase the growth rate of trees due to in increase of effectiveness of photosynthesis. (Stomata will have to be open less longer to require the same amount of CO$_2$ and therefore trees will lose less water for example).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Our ocean does absorb CO$_2$ as well. Algea, phytoplankton, and chemical process all make this happen. What you mean with recycle -- as well I'm not sure.&lt;/p&gt;&#xA;" OwnerUserId="10790" LastEditorUserId="5594" LastEditDate="2017-12-02T11:00:23.110" LastActivityDate="2017-12-02T11:00:23.110" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12798" PostTypeId="2" ParentId="12792" CreationDate="2017-12-01T22:06:28.890" Score="1" Body="&lt;p&gt;Chemistry is not a bad thing; life depends on it. And just because a pesticide or herbicide is natural or synthetic has practically nothing to do with its toxicity. Many so-called natural or organic pesticides are many times more potent than widely-used synthetic ones, as &lt;a href=&quot;https://geneticliteracyproject.org/2017/11/22/myth-busting-natural-pesticides-really-safer-synthetic-ones/?mc_cid=0b51d1b46a&amp;amp;mc_eid=d552c8b21b&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; mentions.&lt;br&gt;&lt;br&gt;As to whether or not Glyphosate is necessary, &lt;a href=&quot;https://geneticliteracyproject.org/2017/11/28/eu-re-approval-glyphosate-herbicide-dodges-farming-economic-woes-now/?mc_cid=110fedeb39&amp;amp;mc_eid=d552c8b21b&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; explains some of the economic impacts from an outright Glyphosate ban. Some of the effects include:&lt;blockquote&gt;...French research institute Arvalis suggested a ban would cost that country’s agriculture industry 976 million euros ($1.1 billion). And in Germany, the Kleffmann Group said restrictions could hurt barley and corn output—with profit margin shrinkage between 40 and 70 percent–as farmers start planting alternative, more profitable crops.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meanwhile, in the United Kingdom, where in 2014 2.2 million hectares of farms—a third of arable land—was treated with glyphosate, Oxford Economics estimated the impact would reduce wheat yields by 12 percent, oilseed/rape yields by 14 percent, and cereal production by 15 percent. Agricultural contributions to the nation’s GDP would shrink by about £930 million ($1.23 billion).&lt;/blockquote&gt;&lt;br&gt;In another article I recall reading (but can't find the citation for), Glyphosate is applied at a rate of only one pint per acre. Farms are not drenched in it as many anti-Glyphosate advocates would have us believe.&lt;br&gt;&lt;br&gt;As to whether or not Glyphosate is a carcinogen, &lt;a href=&quot;https://geneticliteracyproject.org/2017/11/27/french-scientist-calls-inquiry-iarcs-misbehavior-glyphosate-cancer-study/?mc_cid=110fedeb39&amp;amp;mc_eid=d552c8b21b&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; calls much of that into question. Apparently, there were individuals involved who might have benefited substantially by having Glyphosate declared a human carcinogen.&lt;br&gt;&lt;br&gt;&lt;b&gt;Edit:&lt;/b&gt;Some other interesting articles:&lt;br&gt;&lt;br&gt;&lt;a href=&quot;http://www.factcheck.org/2017/08/glyphosate-cause-cancer/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article &lt;/a&gt; from Factcheck.org had this interesting tidbit&lt;blockquote&gt;Q: Does the herbicide glyphosate cause cancer? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A: There is evidence to suggest it may cause cancer at very high doses, but not at the low doses typically found in foods.&lt;/blockquote&gt;and&lt;blockquote&gt;&#xA;The European Chemicals Agency...concluded in March 2017 that “the available scientific evidence did not meet the criteria to classify glyphosate as a carcinogen.”&lt;/blockquote&gt;&lt;br&gt;And &lt;a href=&quot;https://www.the-scientist.com/?articles.view/articleNo/50921/title/Long-term-Study-Finds-That-the-Pesticide-Glyphosate-Does-Not-Cause-Cancer/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; from the-scientist.com said &lt;blockquote&gt;A new study has found no conclusive link between exposure to glyphosate—the main ingredient in a popular weedkiller—and cancer.&lt;/blockquote&gt;&lt;br&gt;And Reuters in &lt;a href=&quot;https://www.reuters.com/investigates/special-report/glyphosate-cancer-data/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this piece &lt;/a&gt; said:&lt;blockquote&gt;&#xA;The World Health Organization's cancer agency says a common weedkiller is &quot;probably carcinogenic.&quot; The scientist leading that review knew of fresh data showing no cancer link - but he never mentioned it and the agency did not take it into account.&lt;/blockquote&gt;&lt;/p&gt;&#xA;" OwnerUserId="2959" LastEditorUserId="2959" LastEditDate="2017-12-04T19:26:37.240" LastActivityDate="2017-12-04T19:26:37.240" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="12799" PostTypeId="2" ParentId="8094" CreationDate="2017-12-02T00:19:25.923" Score="4" Body="&lt;p&gt;It takes about 2 weeks for a mass of air to circle the globe along its latitude from West to east. I used to work for a French climate research lab in the 70s, and was based on Crozet island (South Indian Ocean) . At the time I was carrying atmospheric radioactivity measurements, and the French army was carrying nuclear test above ground in the pacific, I could see the radioactive cloud passing above me about 10 days later and then again about every second week after that and about completely disappeared after 6 months.&#xA;In the case you raise, you will benefit from cleaner air about one week after the decommissioning&lt;/p&gt;&#xA;" OwnerUserId="11667" LastActivityDate="2017-12-02T00:19:25.923" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12800" PostTypeId="2" ParentId="12788" CreationDate="2017-12-02T01:44:33.530" Score="1" Body="&lt;p&gt;You would be lucky if you could identify it with only elemental composition. XRD would be the best method to identify material ( the elemental composition is also needed ). Our lab normally used XRD and XRF , and only went to the SEM when special information was needed.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2017-12-02T01:44:33.530" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12801" PostTypeId="1" AcceptedAnswerId="12813" CreationDate="2017-12-02T02:21:54.080" Score="5" ViewCount="4376" Body="&lt;p&gt;I've found 2 sources stating that there is new water being formed on Earth.  The &lt;a href=&quot;http://www.answers.com/Q/Where_does_new_water_on_earth_come_from&quot; rel=&quot;noreferrer&quot;&gt;first site&lt;/a&gt; states that it is coming from hydrothermal vents in the sea floor.  The &lt;a href=&quot;https://www.thenakedscientists.com/articles/questions/any-new-water-being-formed-our-planet&quot; rel=&quot;noreferrer&quot;&gt;second site&lt;/a&gt; is basically saying that new water is being generated through biological processes.  However, to me, this just seems water that is already here coming up to the surface in the case of hydrothermal vents, or the rearranging of atoms into water molecules through biological processes that are already here on Earth.  Maybe this explanation is just semantics, but I'm also wondering if new water is coming here from meteors/meteorites.  To me that would be new water on Earth.  Is there any definitive proof of new water being formed on or brought to Earth?  &lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastEditorDisplayName="user11318" LastEditDate="2017-12-02T02:31:21.507" LastActivityDate="2017-12-14T06:53:21.840" Title="Is there any new water formed on, or brought to, Earth?" Tags="|meteorology|water|meteorite|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12803" PostTypeId="1" CreationDate="2017-12-02T20:10:25.187" Score="-2" ViewCount="62" Body="&lt;p&gt;Given a bare but not sterile environment and the sorts of supplies one would have access to in a well-stocked cafeteria or a bad grocery store, is it possible to start growing food? Assume frozen, canned and otherwise processed food is available but fresh fruits and vegetables are not. Phrased another way: What are the minimum requirements to be able to cultivate food?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I realise this question is relatively broad, but I hope it's okay to ask here - I'm asking this for a story I'm trying to write. I have very little knowledge about farming, except for a vague impression that you can grow things in coffee grounds and that you can make prison wine using bread and fruit juice. &lt;/p&gt;&#xA;" OwnerUserId="11686" LastActivityDate="2017-12-03T01:45:43.347" Title="Is it possible to set up a farm starting with processed foods?" Tags="|agriculture|" AnswerCount="2" CommentCount="1" ClosedDate="2017-12-03T10:28:59.800" ContentLicense="CC BY-SA 3.0" />
  <row Id="12806" PostTypeId="2" ParentId="12803" CreationDate="2017-12-03T00:04:27.710" Score="0" Body="&lt;p&gt;I believe it would be entirely possible to grow a viable source of fruits, vegitables, and grain products.  Soley from you’re grocery listed of processed frozen and canned foods. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Frozen fruits, vegitables, and meats under go a process called &lt;em&gt;flash freezing&lt;/em&gt;&lt;a href=&quot;http://m.wisegeek.org/what-is-flash-freezing.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;. Flash freezing has the ability to lock in the vast majority of the produces natural or &lt;a href=&quot;https://en.wikipedia.org/wiki/Food_fortification?wprov=sfti1&quot; rel=&quot;nofollow noreferrer&quot;&gt;food fortified&lt;/a&gt; nutritional content. Making these particular items great candidates for &lt;a href=&quot;https://eartheasy.com/grow_compost.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;composting&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now say one allowed those canned processed fortified foods or non. To vermicompost over time to create a nutrient rich, well balanced soil. Then planted crops accordingly. I believe that one could cultivate goods that would thrive rather nicely in the biological make up of your produce soils.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://eartheasy.com/grow_compost.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;eartheasy.com guide to compost&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://m.wisegeek.org/what-is-flash-freezing.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;wisegeeks.org definition of flash freezing&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Food_fortification?wprov=sfti1&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia.org/wiki/Food_fortification&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="11565" LastActivityDate="2017-12-03T00:04:27.710" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12807" PostTypeId="2" ParentId="12329" CreationDate="2017-12-03T00:17:28.987" Score="-1" Body="&lt;p&gt;You could try........&lt;a href=&quot;http://dmpbookshop.eruditetechnologies.com.au/product/the-pilbara-drilling-project-c-272-ga-tumbiana-formation-and-c-349-ga-dresser-formation-pilbara-craton-western-australia.do&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://dmpbookshop.eruditetechnologies.com.au/product/the-pilbara-drilling-project-c-272-ga-tumbiana-formation-and-c-349-ga-dresser-formation-pilbara-craton-western-australia.do&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And a few references in..&lt;a href=&quot;http://geodocs.dmp.wa.gov.au/viewer/multipageViewerAction.do?documentId=440287&amp;amp;viewMarkId=0&amp;amp;ct=true&amp;amp;at=none&amp;amp;btv=true&amp;amp;atv=false&amp;amp;vmtv=false&amp;amp;ac=ff0000&amp;amp;cabinetId=1101&amp;amp;pg=0&amp;amp;scl=64&amp;amp;bds=0|0|2560|3584&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://geodocs.dmp.wa.gov.au/viewer/multipageViewerAction.do?documentId=440287&amp;amp;viewMarkId=0&amp;amp;ct=true&amp;amp;at=none&amp;amp;btv=true&amp;amp;atv=false&amp;amp;vmtv=false&amp;amp;ac=ff0000&amp;amp;cabinetId=1101&amp;amp;pg=0&amp;amp;scl=64&amp;amp;bds=0|0|2560|3584&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11694" LastActivityDate="2017-12-03T00:17:28.987" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12809" PostTypeId="2" ParentId="12803" CreationDate="2017-12-03T01:45:43.347" Score="1" Body="&lt;p&gt;Do you have another source of seeds, or are you hoping to get all the seeds to jump-start agriculture from processed food in a grocery store? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the latter... a lot of our processing kills seeds while sterilizing food. Often we remove the seeds in the first place. For instance, I rarely see bell-pepper seeds in frozen sliced bell pepper, or tomato seeds in sauce. There are seeds in frozen okra, but okra is a hot-climate plant, I don't know if its seeds survive freezing. There might be whole flax and sesame seeds in granola that could still sprout.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think you should put a damp paper towel somewhere warm and  test things as you find them in the grocery. &lt;/p&gt;&#xA;" OwnerUserId="2639" LastActivityDate="2017-12-03T01:45:43.347" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12810" PostTypeId="2" ParentId="8877" CreationDate="2017-12-03T02:48:18.527" Score="2" Body="&lt;p&gt;There's still a lot that isn't understood about the Earth's magnetic field, so there's some uncertainty to any answer to your question.   That said, I touch on some of it.   &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;isn't the current that causes the magnetic field affected by the&#xA;  Earth's axis&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'd say probably not.  We can see this by looking at other objects with magnetic fields relative to their axis.  There are some theories that planets need to rotate to have magnetic fields, but Mercury rotates very slowly and it has a small magnetic field.  Mars rotates with a similar period to Earth and it lost it's magnetic field about 4 billion years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bP8ra.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bP8ra.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and &lt;a href=&quot;https://imagine.gsfc.nasa.gov/science/objects/neutron_stars1.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Neutron Stars&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Often, the magnetic field is not aligned with the spin axis&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The Magnetic Axis and the Axis of Rotation seem to have very little to do with one another.  The Rotation Axis' relation to the plane of the solar system, I suspect that has even less influence, but I have no idea how to go about explaining the why behind that, it just feels improbable to me because the effect seems more internally generated and the inside of the Earth cares which way it spins and stretches, but not how it lines up with the plane of the solar system - (I would guess).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition, the Earth's Magnetic North Pole moves around.  Earth's Axis changes very slowly.  It's difficult to see a relation between the two beyond &quot;in the same general area&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YCWFO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YCWFO.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;(or perhaps the orbit around the sun)?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It's always good to explore possibilities.  Pretty interesting, short article on &lt;a href=&quot;https://kendalastronomer.wordpress.com/2009/05/07/how-did-mars-lose-its-magnetic-field/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mars' loss of it's Magnetic field here&lt;/a&gt; that suggests it's the inner workings of the planets that drive magnetic fields.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When there's enough temperature variation and a liquid medium, spirals (or swirles) can form because circulation is more efficient than convection at heat transfer.  Like the atmosphere, you also have the hotter material wanting to expand and rise and the cooler more condensed material wanting to fall, but you also have increasing pressure as you go down, and, perhaps, not uniform molecular density, so it's a pretty tricky subject requiring lots of math behind when spirals form and when they don't.  The solidifying of the other core into the inner core and heat released from that phase change may play a role too.  (I read that, will post a source if I can find one).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2MsA6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2MsA6.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth's relatively rapid rotation (and corresponding Coriolis effect) might keep the magnetic field pointing roughly North-South (I would guess) but as noted in the map above, there's a fair bit of wobbling and in addition to that, every few hundred thousand years &lt;a href=&quot;https://www.nasa.gov/topics/earth/features/2012-poleReversal.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;the field flips&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://astronomynow.com/2016/04/01/moon-thought-to-play-major-role-in-maintaining-earths-magnetic-field/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Moon may cause the movement&lt;/a&gt; of the magnetic poles too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/P7AUE.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/P7AUE.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;(or perhaps the orbit around the sun)?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(yes, I just quoted you twice)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That article just above suggests the stretching and squashing of the Earth, both due to the Moon and the Sun would have an effect, so in a sense, the Orbit around the Sun might affect the magnetic field, but more the tidal effects from the Sun than the actual orbit itself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because this field remains unresolved, we should never say never until it's better understood.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2017-12-03T02:48:18.527" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12811" PostTypeId="2" ParentId="12791" CreationDate="2017-12-03T03:26:37.117" Score="2" Body="&lt;p&gt;While your question isn't ideal, in that it's 3 separate questions and there's not much indication that you've done any research, I'll answer anyway.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is year twenty -thirty an accurate prediction for polar ice&#xA;  extinction?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Nobody knows if it's accurate.  It's certainly a reasonable estimate based on current rates of decline and continued warming.   Predicting something like that with accuracy, however, is impossible.  But they can usually make pretty good estimates with careful study.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, I wouldn't call it an extinction of ice because the ice will return every winter, it's just an ice-free summer.   Is it still bad?  Yes.  An ice-free Arctic in summer should be prevented if we can.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A.) Is there a model to show just how much our forests absorbs green&#xA;  house gases?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is also a very difficult question.   Forests absorb CO2 but they also release it when plants and animals die and/or get eaten.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nasa.gov/jpl/nasa-finds-good-news-on-forests-and-carbon-dioxide&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA estimates up to 30% of our CO2&lt;/a&gt; is currently absorbed by all the forests in the world, but the article describes the difficulty in reaching that estimate.  Similar estimate &lt;a href=&quot;https://phys.org/news/2013-06-carbon-world-forests-absorb.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;from this article&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem, of-course, is we can't exactly double or triple the amounts of forests we have in the world.   We don't have that much free space.   Maintaining forests and planting trees can help with climate change but it's unlikely to ever be a fix.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Will an abundance of CO2 &amp;amp; methane-gas over load the earths forests &amp;amp;&#xA;  oceans natural ability absorb such gases and start to kill them off.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No.  Methane is too scarce to have much effect and CO2 is, if anything, good for plants, not bad for them.  Some studies suggest increased levels in CO2 increase plant growth.   There are other related problems.  Flooding, hurricanes, droughts, salt from storm surges can hurt, not help plant growth.   While the CO2 increase can be a boost to plants, environmental changes can hurt.  CO2 isn't a pollutant and it doesn't kill planets at high levels.   Greenhouses, for example often store 3 or 4 times the normal CO2 concentration without any harm to the plants.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;C.) Does our ocean's plankton act as a mechanism to recycle the atmospheres CO2 Green house gases.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not as well as forests.  Plankton does absorb a lot of carbon by photosynthesis but most &lt;a href=&quot;https://www.gdrc.org/oceans/fsheet-02.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;gets returned back into the atmosphere&lt;/a&gt;.   &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Although a small but possibly significant percentage of the sinking&#xA;  organic material becomes buried in the ocean sediment, most of the&#xA;  dissolved carbon dioxide is eventually returned to the surface via&#xA;  ocean currents - but this can take centuries or millennia.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It's also unclear how much longer the oceans will continue to absorb carbon or if they will &lt;a href=&quot;https://www.newscientist.com/article/dn20413-warmer-oceans-release-co2-faster-than-thought/&quot; rel=&quot;nofollow noreferrer&quot;&gt;start to release it as they warm up&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's better to ask one question at a time, not three or four, and also, do research before you ask.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2017-12-03T14:10:34.493" LastActivityDate="2017-12-03T14:10:34.493" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12812" PostTypeId="1" CreationDate="2017-12-03T03:34:12.220" Score="2" ViewCount="65" Body="&lt;p&gt;The project would be to place about a dozen sensors in &quot;swarm&quot; fashion and have them collect data from the Atlantic ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sensors would be about the size of a softball and would be retrieved days later after data is collected.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've been looking at regulations and permits needed for this but only find construction based permits for building homes or factories near the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a permit I need to pull for this or a body who regulates this kind of research?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And would a different permit be needed if the sensors weren't meant/or unable to be retrieved?&lt;/p&gt;&#xA;" OwnerUserId="10833" LastActivityDate="2017-12-06T16:44:17.563" Title="Do I need a permit for putting retrievable sensors in ocean (Atlantic)?" Tags="|ocean|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12813" PostTypeId="2" ParentId="12801" CreationDate="2017-12-03T03:47:52.447" Score="5" Body="&lt;p&gt;Your explanation(s) sounds correct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your &lt;a href=&quot;http://www.answers.com/Q/Where_does_new_water_on_earth_come_from&quot; rel=&quot;noreferrer&quot;&gt;first article says as much&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;There is a water cycle on earth that takes wet sediments deep into the&#xA;  mantle to be re heated and circulated back up as new sea floor. This&#xA;  is where the water in hydrothermal vents originates - &lt;strong&gt;it is NOT new&#xA;  water.&lt;/strong&gt; However, there remains a possibility that some of the water&#xA;  emerging from the mantle has been there since the formation of the&#xA;  earth so some of it MAY be 'new'.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And your &lt;a href=&quot;https://www.thenakedscientists.com/articles/questions/any-new-water-being-formed-our-planet&quot; rel=&quot;noreferrer&quot;&gt;2nd article&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is at least partly semantics calling it &quot;new&quot; water.  When we burn gasoline for example, the hydrocarbon structure becomes Water and CO2 - is that new water, or just re-arranging molecules by chemical reaction and fire?&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I'm also wondering if new water is coming here from&#xA;  meteors/meteorites.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Water absolutely reaches the Earth by comets and meteors.   We're hit by comets and meteors all the time and comets especially are water-rich.   That is new water, though I wouldn't want to put an estimate on how much.  Too big a margin of error.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth also loses water &lt;a href=&quot;https://phys.org/news/2016-07-curious-case-earth-leaking-atmosphere.html&quot; rel=&quot;noreferrer&quot;&gt;by UV rays from the sun&lt;/a&gt;.   Most of the atmosphere the Earth loses is Hydrogen and most of that Hydrogen comes from Water.   Losing 90 tonnes of Hydrogen per day works out to nearly 800 tons of water per day, which sounds like a lot, but compared to the vastness of our oceans, it's a proverbial drop in the bucket, even over hundreds of millions of years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So Earth adds water by comets and Earth loses water by photo-disintigration and atmospheric escape.   I've read that it's a net loss, not a net gain, but it's pretty insignificant either way.    Some articles suggest &lt;a href=&quot;http://sciencenordic.com/earth-has-lost-quarter-its-water&quot; rel=&quot;noreferrer&quot;&gt;Earth has lost a pretty good share of it's water&lt;/a&gt; over billions of years.   I think there's a pretty big margin of error in those estimates, personally. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In 200 or 300 million years, as the sun grows a little larger and brighter, we might need to begin to worry about Earth losing too much water (maybe).  That's if we're still around, of-course.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2017-12-03T03:47:52.447" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12814" PostTypeId="1" CreationDate="2017-12-03T05:38:49.380" Score="4" ViewCount="1751" Body="&lt;p&gt;Why does the colour of Earths oceans vary? Coast lines around the world appear to have different shades of blue.  The further one travels from the equator north or south the deep blue the ocean becomes. Is this effect a result of ocean temperature or salinity? &lt;/p&gt;&#xA;" OwnerUserId="11565" LastActivityDate="2017-12-05T06:00:06.827" Title="Why does the colour of Earths oceans vary?" Tags="|ocean|oceanography|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12815" PostTypeId="2" ParentId="12814" CreationDate="2017-12-03T08:14:41.650" Score="6" Body="&lt;p&gt;The color of the ocean water does indeed vary depending on the chemical composition of the water. In addition, the color of the ocean in satellite images is affected by the position of the satellite, angel of the sun, and weather.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Color of water in general&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Water appears blue because long wavelengths (red or yellow light) are absorbed more efficiently in water than short (blue or green) wavelengths. Therefore, when a water body — in a swimming pool, for example — is illuminated by a white light source (the sun) the light that scatters back from the water tends to be blue rather than red.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The color of the water can further be altered by its &lt;strong&gt;chemical composition&lt;/strong&gt;. In nature, the &lt;em&gt;apparent&lt;/em&gt; color of water also depends on the light source, that is, &lt;strong&gt;the weather&lt;/strong&gt;. The same ocean can appear very different in bright sunlight and on a cloudy, stormy day.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Color depends on substances in the water&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The color of the ocean water can be greatly altered by &lt;strong&gt;substances dissolved or suspended in the water&lt;/strong&gt;.&#xA;Typical substances that affect the color are &lt;strong&gt;chlorophyll&lt;/strong&gt; (from waterborne algae) that make water appear green, or &lt;strong&gt;suspended particulate matter&lt;/strong&gt;, such as silts and clay, that cause yellow or brown color. These are clearly seen in coastal areas, where local plankton blooms can turn water bright green, or river plumes carrying a high concentration of suspended particulate matter can be clearly identified from their brown waters. Other substances can alter the color of water as well. Colored dissolved organic matter (CDOM) related to decaying detritus, can turn water yellowish or green, for example. Water temperature and salinity themselves do not significantly affect the color of the water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The color of the ocean, therefore, does depend on the location. For example, waters in areas with high primary production tend to be more green.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Color of oceans in satellite images&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;In satellite images, the color of the ocean can be influenced by the &lt;strong&gt;relative angle&lt;/strong&gt; of &lt;strong&gt;the sun&lt;/strong&gt; and &lt;strong&gt;the satellite&lt;/strong&gt; versus the ocean surface. The ocean can appear darker if the satellite is at an oblique angle with respect to the ocean surface and/or if the sun is shining from an acute angle. In the case of geostationary satellites, the ocean near the equator can therefore appear to be brighter than in the high latitudes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Moreover, the color of oceans may be affected by the &lt;strong&gt;surface roughness&lt;/strong&gt;. &lt;strong&gt;Surface waves&lt;/strong&gt; affect the way light is reflected and refracted in the surface and may cause the ocean to appear darker.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consequently, the color of oceans may vary greatly in satellite images due to the track of the satellite and local weather conditions. This is often visible in large composite images, made out of multiple satellite tracks, where the ocean may appear patchy with different colors.&lt;/p&gt;&#xA;" OwnerUserId="11700" LastActivityDate="2017-12-03T08:14:41.650" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12819" PostTypeId="2" ParentId="8515" CreationDate="2017-12-03T20:24:35.917" Score="2" Body="&lt;p&gt;I haven't seen those videos, but in general yes, the rotation of the Earth has a major impact on weather and climate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The weather and climate are primarily driven by solar radiation that heats up the surface of the Earth and drives global winds and ocean currents. The rotation of the Earth has a major impact in this process, due to the day/night variability of solar radiation, and the Coriolis effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, all storms, hurricanes, and tornadoes do rotate in the so-called cyclonic direction, that is counterclockwise in the Northern hemisphere. This is a direct consequence of the Coriolis force, that is, the rotation of the Earth. All cyclones are close to a geostrophic balance, which means that the Coriolis force is balanced by a pressure gradient force. That is why storms can last for long periods of time and travel long distances. If the Earth didn't spin, such storms could not exist.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact, most phenomena related to weather are affected by the Coriolis effect, for example, the trade winds, jet stream, different air masses, and typical precipitation patterns. None of these would exist if the Earth did not rotate about its axis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rotation speed also affects these phenomena. If the rotation rate of the Earth was larger, for example, then storms would have smaller radius but feature stronger winds. If the rotation rate was significantly different (say, twice as fast), it is likely that both the weather and climate of the Earth would be completely different.&lt;/p&gt;&#xA;" OwnerUserId="11700" LastActivityDate="2017-12-03T20:24:35.917" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12820" PostTypeId="2" ParentId="12788" CreationDate="2017-12-04T03:41:25.787" Score="1" Body="&lt;p&gt;I have to disagree with with @blacksmith37and @Gabija. Using an SEM is one of the best methods there are to identify minerals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;XRD is only useful if you have a nice single crystal, or if you have the material powdered. If it's a mineral in a rock, then the powder will be a mixture of everything, unless you can separate the mineral out. SEM-EDS analysis (which is what you probably did) gives you the chemical composition of the mineral, which is usually sufficient for identification.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some cases where it doesn't work:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Polymorphs. Quartz or coesite, calcite or aragonite. They will have the same composition. But ideally you have some prior information on the rock so you know what to expect.&lt;/li&gt;&#xA;&lt;li&gt;X-ray energy overlap. Some elements overlap in the energies, for example Mo, Pb and S. You will only get one peak for them, making it hard to distinguish. But, usually galena (PbS) and molybdenite (MoS2) look so different, so it shouldn't be too hard. Another example is Ti and Ba. If you analyse a feldspar and you get some Ti, it's most likely to be Ba because that's what goes into feldspar, not Ti.&lt;/li&gt;&#xA;&lt;li&gt;Light elements. It's not possible to analyse Li and Be so no spodumene or beryl.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Even though there are problems, it's still an excellent way to do it.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I know I would need standards to do so but I not sure how to go about this&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Too late for that. Measuring standards is part of the instrument's calibration, and you do that before you analyse your minerals. It might have already been done by the SEM operator - just ask them. Unfortunately, many SEMs have standard-less EDS systems, where it's calibrated once in the factory and that's it. Fortunately, the results you get from such systems are surprisingly good, particularly for simple minerals. The problem is that they normalise the results, so it's hard to know if you have a hydrous mineral or just a bad analysis.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;how would I go about quantifying the sample's composition? &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You already have everything. Mineral compositions are usually reported in oxide wt%, so you get this information straight off the SEM. Mineral formulas are a bit more tricky. You first need to know which minerals it is, and then you need to know how much oxygens it has. For example, olivine has four oxygens: Mg&lt;sub&gt;2&lt;/sub&gt;SiO&lt;sub&gt;4&lt;/sub&gt;. Then you need to normalise your (atomic%) data to that number of oxygens. Here's a website that explains this very well:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://serc.carleton.edu/research_education/equilibria/mineralformulaerecalculation.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://serc.carleton.edu/research_education/equilibria/mineralformulaerecalculation.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And in general, a web search for &quot;calculating mineral formula&quot; results in many sites that have worked out examples on how to do it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have the composition, but you have no idea what mineral it is, there are two websites that can assist you:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://webmineral.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://webmineral.com/&lt;/a&gt; This site lists the composition of each minerals in oxide% and wt%, so you can compare it with your analyses.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.mindat.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.mindat.org/&lt;/a&gt; This site has a search by chemistry. You just type in the elements you have from your analysis and it gives you a list of minerals that have them. Then try to look at the relative proportions of you atomic% to try and figure out which mineral it can be.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2017-12-04T04:34:21.453" LastActivityDate="2017-12-04T04:34:21.453" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12821" PostTypeId="2" ParentId="8515" CreationDate="2017-12-04T08:16:55.857" Score="4" Body="&lt;p&gt;Weather modeling is crazy complicated so I don't want to make this sound absolute, but Venus virtually doesn't rotate and it has much &lt;a href=&quot;http://www.astronomy.com/news/2013/06/the-fast-winds-of-venus-are-getting-faster&quot; rel=&quot;nofollow noreferrer&quot;&gt;faster trade winds than Earth&lt;/a&gt;.   Venus has low surface wind speed but that has to do with the consistent temperature all around it's surface and a very dense almost viscus atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might not get hurricanes with a slow rotation and virtually no Coreolis, but you'd still get weather.  The heavy cold air from the night side of the planet would sink and the hot day side of the planet would rise, and you'd get a constant re-balancing of density and a steady wind and likely a lot of rain as the air cooled on the night side, perhaps continuous rain at a certain time during the night (the same process that creates dew but much bigger).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some good answers on a &lt;a href=&quot;https://worldbuilding.stackexchange.com/questions/4850/how-would-winds-behave-on-a-tidally-locked-planet&quot;&gt;related question here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2017-12-04T08:16:55.857" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12823" PostTypeId="1" CreationDate="2017-12-04T19:37:41.473" Score="1" ViewCount="326" Body="&lt;p&gt;This question is in the context of velocity model building for reflection seismic imaging (between 0km and 10km in a sedimentary basin).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is really a rock physics question disguised as an imaging question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;A brief description of what I am trying to do:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to perform seismic imaging (aka seismic migration), we assume that the velocity structure of the earth is known. This allows us to place the recorded reflection amplitudes in the correct location in 3D space to give us a real representation of the underlying geology (including depth, dips, and scaled reflection coefficients).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can obtain this laterally varying velocity model from iterative traveltime tomography of the same data. We typically account for the polar velocity anisotropy (i.e. difference in velocity of the same rock when measured parallel vs perpendicular to bedding planes) in the form of &lt;a href=&quot;https://en.wikipedia.org/wiki/Transverse_isotropy#Thomsen_parameters&quot; rel=&quot;nofollow noreferrer&quot;&gt;Thomsen parameters&lt;/a&gt;, in a symmetry model usually called TTI (tilted transverse isotropy). The final model consists of 5 spatially varying parameters:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Theta (angle of structural dip, the axis of symmetry is assumed perpendicular to bedding)&lt;/li&gt;&#xA;&lt;li&gt;Phi (angle of structural strike, the axis of symmetry is assumed perpendicular to bedding) &lt;/li&gt;&#xA;&lt;li&gt;V0 (velocity along this axis of symmetry)&lt;/li&gt;&#xA;&lt;li&gt;Epsilon (Thomsen parameter describing the magnitude of large angle anisotropy)&lt;/li&gt;&#xA;&lt;li&gt;Delta (Thomsen parameter describing the magnitude of small angle anisotropy)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Theta and Phi are easy to obtain directly from the seismic image (this is in part why this process is iterative).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An initial model for V0, epsilon, and delta is created from sparse well data and further detail is obtained between control points by using tomography. In practice, epsilon and delta are assumed to be linearly related and that the linear relation holds throughout the dataset (this is usually a good assumption).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This leaves us solving for really just two things in tomography: V0 and delta. However, there is an intrinsic non-uniqueness, made worse by noise, in which different combinations of V0 and delta explain the data equally well (i.e. &lt;a href=&quot;http://www.subsurfwiki.org/wiki/Gather&quot; rel=&quot;nofollow noreferrer&quot;&gt;image gather flatness&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;So the motivation for my question is this:&lt;/strong&gt; How can I use &lt;em&gt;a priori&lt;/em&gt; geologic data to guide the solution of this ill-posed inverse problem?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am very skeptical about having the geologic structure guide V0 since my dataset is in an active foreland basin with strong active deltaic deposition. This means that my sediments (structurally deformed progradational sand-shale sequences) are very unconsolidated and compaction (therefore, depth) is the main driver of velocity rather than stratigraphy. In other words, I expect velocity contours to cross structural ones in areas of high dip (and I have evidence of these normal compaction trends from well data).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Which now leads to my question:&lt;/strong&gt; Can I use the geologic structure to guide my Thomsen delta (i.e. the degree of anisotropy)? Does it make sense to assume that even though compaction is the main driver for velocity in unconsolidated sediments, stratigraphy is the main driver of anisotropy?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe a more useful question: What other measurements or observations would I need to make to validate or reject this assumption?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this assumption makes sense, I can add the additional constraint (as a regularization term) to the tomographic inverse problem such that the solution for delta must (at least somewhat) follow the structural dip (i.e. theta and phi).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;" OwnerUserId="4636" LastEditorUserId="4636" LastEditDate="2017-12-04T19:45:36.393" LastActivityDate="2018-02-07T20:16:11.863" Title="Does seismic anisotropy follow stratigraphy?" Tags="|seismic|stratigraphy|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12824" PostTypeId="1" CreationDate="2017-12-04T22:24:19.560" Score="1" ViewCount="1456" Body="&lt;p&gt;I am supposed to design a road trip (&lt;strong&gt;using major highways&lt;/strong&gt;) across North America. I have to design a route that starts with the oldest rock of Archean age and finishes with the youngest rock of Quaternary age. I have to include the following in sequence from &lt;strong&gt;oldest to youngest:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Archean &lt;/li&gt;&#xA;&lt;li&gt;Proterozoic &lt;/li&gt;&#xA;&lt;li&gt;At least two periods in the Paleozoic &lt;/li&gt;&#xA;&lt;li&gt;Mesozoic&lt;/li&gt;&#xA;&lt;li&gt;At least two periods in the Cenozoic&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I've tried a few things (&lt;strong&gt;USGS, Macrostrat, OneGeology&lt;/strong&gt;) to help me but I am really lost, can anyone &lt;strong&gt;recommend a possible highway route or areas to focus on?&lt;/strong&gt; &lt;/p&gt;&#xA;" OwnerUserId="11724" LastActivityDate="2017-12-05T19:13:29.803" Title="Oldest to Newest Bedrock in the USA &quot;road trip&quot;" Tags="|geology|rocks|time|geologic-layers|bedrock|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12825" PostTypeId="1" CreationDate="2017-12-04T23:02:40.867" Score="0" ViewCount="159" Body="&lt;p&gt;I’m interested to know how much Co2 is generated by a coal fired power station to produce 1kWh of electricity for electrical grid &lt;/p&gt;&#xA;" OwnerUserId="11725" LastEditorUserId="11725" LastEditDate="2017-12-04T23:15:43.567" LastActivityDate="2017-12-05T00:47:01.780" Title="Roughly how much Co2 is generated per kWh of electricity generated" Tags="|environmental-protection|coal|" AnswerCount="1" CommentCount="3" ClosedDate="2017-12-10T17:14:19.570" ContentLicense="CC BY-SA 3.0" />
  <row Id="12826" PostTypeId="2" ParentId="12825" CreationDate="2017-12-05T00:47:01.780" Score="1" Body="&lt;p&gt;About 900 grammes of CO2 for each 1kWh of electricity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is some variation: very modern super-critical coal plants can be lower. But 900g is a reasonable central estimate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that that's just CO2 from combustion. It can be higher, when we include CO2 and CH4 emissions from the rest of the coal supply chain too.&lt;/p&gt;&#xA;" OwnerUserId="100" LastActivityDate="2017-12-05T00:47:01.780" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12827" PostTypeId="1" CreationDate="2017-12-05T01:35:46.047" Score="1" ViewCount="24" Body="&lt;p&gt;I want to determine the effect of surface water quality or the effect of chemicals used on surface like fertilizers on groundwater. What choices do I have for predicting groundwater quality? What are pros and cons of different available models? The model/models should particularly be able to simulate behaviour of pollutants in unsaturated zone!&lt;/p&gt;&#xA;" OwnerUserId="5557" LastActivityDate="2017-12-05T01:35:46.047" Title="What models are available to estimate effect of surface water on groundwater quality?" Tags="|models|groundwater|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12828" PostTypeId="1" CreationDate="2017-12-05T02:49:36.637" Score="4" ViewCount="2769" Body="&lt;p&gt;The way I understand the basics of global warming is we are putting to much CO&lt;sub&gt;2&lt;/sub&gt; into the atmosphere which increases the size / density of atmosphere shell, sun rays enter the atmosphere then there is some reflection off the earth and then the reflected rays get trapped within the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;What I was wondering if solar panels absorb the sun rays, is there then less of the suns rays reflected back into the atmosphere, or is some of the strength reduced?&lt;/p&gt;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="11725" LastEditorUserId="2470" LastEditDate="2022-05-05T17:59:23.320" LastActivityDate="2022-05-05T17:59:23.320" Title="Do solar panels reduce the amount of suns rays reflected back into the atmosphere? Therefore reducing global warming" Tags="|climate-change|environmental-protection|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="12829" PostTypeId="1" CreationDate="2017-12-05T04:00:03.903" Score="1" ViewCount="179" Body="&lt;p&gt;I currently have depth data that I am plotting with the code below. The problem that I am having has to do with the figure python is spitting out. The figure is really tiny. I have tried a few things but nothing came out. Check the code below and the figure. Any help is appreciated.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;from netCDF4 import Dataset&#xA;from mpl_toolkits.basemap import Basemap&#xA;import mpl_toolkits as mplt&#xA;import matplotlib.pyplot as plt&#xA;import numpy as np&#xA;&#xA;f = Dataset(&quot;/Documents/SchoolHR/Data/depth_data.nc&quot;)&#xA;&#xA;# extract and label column&#xA;lats = f.variables['lat'][:]  # extract/copy the latitude data&#xA;lons = f.variables['lon'][:]  # extract/copy the longitude data&#xA;depth = f.variables['Band1'][:]&#xA;lon_0 = lons.mean()&#xA;lat_0 = lats.mean()&#xA;&#xA;&#xA;#create map projection&#xA;m = Basemap(projection = 'stere', width = 5*10**6, height = 35*10**5, resolution = 'l', lat_ts = 40, lat_0 = lat_0, lon_0 = lon_0)&#xA;&#xA;# Plot of global temperature on our random day&#xA;fig = plt.figure()&#xA;fig.subplots_adjust(left=0, right=1, bottom=0, top=0.9)&#xA;&#xA;# Make the plot continuous&#xA;depth_cyclic, lons_cyclic = mplt.basemap.addcyclic(depth, lons) &#xA;&#xA;# compute map projection coordinates for lat/lon grid&#xA;# Create 2D lat/lon arrays for Basemap&#xA;lon2d, lat2d = np.meshgrid(lons_cyclic, lats)&#xA;# Transforms lat/lon into plotting coordinates for projection&#xA;x, y = m(lon2d, lat2d)&#xA;&#xA;# Plot of air temperature with 11 contour intervals&#xA;cs = m.contourf(x, y, depth_cyclic, 11, cmap=plt.cm.Spectral_r)&#xA;cbar = plt.colorbar(cs, orientation='horizontal')&#xA;m.plot(x,y)&#xA;plt.show()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/L4Yw2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/L4Yw2.png&quot; alt=&quot;This should be my depth graph&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11731" LastActivityDate="2017-12-05T04:00:03.903" Title="Issues with projection and fig using python and mpl_toolkits.basemap" Tags="|oceanography|data-analysis|python|bathymetry|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12830" PostTypeId="2" ParentId="12814" CreationDate="2017-12-05T06:00:06.827" Score="2" Body="&lt;p&gt;The question derives from physically being at various locations around the world and witnessing different colours. I chose to use blue as an example because this is how Earth Oceans are commonly referred by.  I do agree that there is various different colour schemes.           &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;There are several theories:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Blue wavelengths are absorbed the least by the deep ocean water and are &#xA;scattered and reflected back to the observer’s eye.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Particles in the water may help to reflect blue light.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The ocean reflects the blue sky.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Most of the time the ocean appears to be blue because this is the color our eyes see. But the ocean can be many other colors depending upon particles in the water, the depth of the water, and the amount of skylight.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The colors we see depend upon the reflection of the visible wavelengths of light to our eyes. The Franklin Institute provides a good explanation of how we see color at &lt;a href=&quot;http://www.fi.edu/color/color.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.fi.edu/color/color.html&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Chlorophyll estimation&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Chlorophyll concentrations are derived from images of the ocean’s color. Generally speaking, the greener the water, the more phytoplankton are present in the water, and the higher the chlorophyll concentrations. Chlorophyll a absorbs more blue and red light than green, with the resulting reflected light changing from blue to green as the amount of chlorophyll in the water increases. Using this knowledge, scientists were able to use ratios of different reflected colors to estimate chlorophyll concentrations.           &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Intrinsic Absorption&lt;/strong&gt;                                                                                                               &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason the ocean is blue is due to the absorption and scattering of light. The blue wavelengths of light are scattered, similar to the scattering of blue light in the sky but absorption is a much larger factor than scattering for the clear ocean water. In water, absorption is strong in the red and weak in the blue, thus red light is absorbed quickly in the ocean leaving blue. Almost all sunlight that enters the ocean is absorbed, except very close to the coast. The red, yellow, and green wavelengths of sunlight are absorbed by water molecules in the ocean. When sunlight hits the ocean, some of the light is reflected back directly but most of it penetrates the ocean surface and interacts with the water molecules that it encounters. The red, orange, yellow, and green wavelengths of light are absorbed so that the remaining light we see is composed of the shorter wavelength blues and violets.                                                                        &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.loc.gov/rr/scitech/mysteries/oceanblue.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.loc.gov/rr/scitech/mysteries/oceanblue.html&lt;/a&gt;&lt;br&gt;&#xA;&lt;a href=&quot;https://science.nasa.gov/earth-science/oceanography/living-ocean/ocean-colour&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://science.nasa.gov/earth-science/oceanography/living-ocean/ocean-colour&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11565" LastActivityDate="2017-12-05T06:00:06.827" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12831" PostTypeId="2" ParentId="12824" CreationDate="2017-12-05T06:49:23.840" Score="2" Body="&lt;p&gt;If you were hoping for a smooth succession from Archean all the way down to Quaternary, you're going to be disappointed. Geology is messier than rocks being serenely laid down continuously through time like that. A drive from the Appalachians to the East Coast would get you everything but the Archaean rocks, although the only Proterozoic rocks would be found in the Piedmont. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The tough part is finding rocks of Archaen age. Although the North American &lt;a href=&quot;http://en.wikipedia.org/wiki/craton&quot; rel=&quot;nofollow noreferrer&quot;&gt;craton&lt;/a&gt; contains Archaen rocks, they are only at the surface in northern Wisconsin and Minnesota (That is, if we restrict ourselves to the United States as you asked), and the Upper Peninsula of Michigan. There are a few outcrops in the Black Hills of South Dakota. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/7/7f/Geologic_Map_Lake_Superior_MN_WI_MI.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's a link&lt;/a&gt; to a large detailed geological map of the three states.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But this is just the bedrock geology. The trouble with looking for Archean age rocks in northern Wisconsin and Minnesota, of course, is that these areas are mostly covered by glacial till from recent ice ages (although you might find an Archean glacial erratic that the ice sheets carried down from Canada). Archean outcrops might be small and inaccessible.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nQGKw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nQGKw.png&quot; alt=&quot;Minnesota bedrock geology&quot;&gt;&lt;/a&gt;&#xA;&lt;em&gt;(Source: Wikimedia commons)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Minnesota has early Archaen (&quot;Superior&quot; craton) rocks and a whole succession of Paleozoic. It has some Cretaceous rocks but lacks other Mesozoic/Cenozoic bedrock. North Dakota has some Jurassic age rocks in its northeastern corner.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iJSIi.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iJSIi.gif&quot; alt=&quot;Wisconsin bedrock geology&quot;&gt;&lt;/a&gt;&#xA;&lt;em&gt;(Source: Steven Dutch, University of Wisconsin Green Bay)&lt;/em&gt;&#xA;&lt;em&gt;&lt;a href=&quot;https://www.uwgb.edu/dutchs/index.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.uwgb.edu/dutchs/index.htm&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wisconsin has late Archaen (&quot;Penokean&quot; craton) rocks and the same lack of later rocks as Minnesota. Wisconsin has a field-trip planning site with an interactive outcrop map &lt;a href=&quot;https://wgnhs.uwex.edu/education-resources/outcrop-descriptions/&quot; rel=&quot;nofollow noreferrer&quot;&gt;at this link&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you could get access to the Black Hills outcrops (uplifted bits of the &quot;Wyoming&quot; craton), you might be able to approximate what tou want with a trip east through South Dakota, starting in the Black Hills. I haven't found an image of South Dakota geology appropriate for embedding, but &#xA;&lt;a href=&quot;http://www.sdgs.usd.edu/pubs/pdf/G-10.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here is a link&lt;/a&gt; to a large, detailed PDF of South Dakota geology, and &lt;a href=&quot;http://www.sdgs.usd.edu/geologyofsd/geosd.html&quot; rel=&quot;nofollow noreferrer&quot;&gt; here is another link&lt;/a&gt; to an interactive site with generalized SD geology. &lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2017-12-05T19:13:29.803" LastActivityDate="2017-12-05T19:13:29.803" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12832" PostTypeId="2" ParentId="12828" CreationDate="2017-12-05T08:52:24.690" Score="1" Body="&lt;p&gt;They do have an effect, but it is minuscule. If rays are absorbed by solar panels then the energy is eventually turned into heat that is released to the atmosphere as hotter air or longwave radiation by the surface. But the main mechanism is the effect in albedo of the surface. As solar panels are dark they usually reflect less light than the background they are installed on. The total area of solar panels is so low that the effect is very very small.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastActivityDate="2017-12-05T08:52:24.690" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12833" PostTypeId="2" ParentId="12828" CreationDate="2017-12-05T09:26:12.627" Score="7" Body="&lt;p&gt;Whether solar panels reduce the amount of suns rays reflected back into space &lt;a href=&quot;https://en.wikipedia.org/wiki/Albedo&quot; rel=&quot;nofollow noreferrer&quot;&gt;depends on their albedo&lt;/a&gt; and the albedo of the surface that they cover.  Desert sand, for example, is fairly reflective and solar panels might reflect less sunlight back into space than deserts, but it's not just the reflection that matters.  You also have to account for energy production.&lt;/p&gt;&#xA;&lt;p&gt;If enough solar panels are built that fossil fuel generated electricity (usually coal or natural gas), can be reduced, by 5% or 10%, that works out to a pretty useful drop in CO&lt;sub&gt;2&lt;/sub&gt; footprint.   Less CO&lt;sub&gt;2&lt;/sub&gt; from burning fossil fuels means less warming.   The ratio of surface temperature by absorbed sunlight vs reflected sunlight is on average, less significant than the heat trapping of CO&lt;sub&gt;2&lt;/sub&gt;.   Explaining that gets kind of long and &amp;quot;mathy&amp;quot; and it's full of approximations, but as a ballpark estimate, 1 joule of energy produced by fossil fuels and the CO&lt;sub&gt;2&lt;/sub&gt; that's released by that process, that CO&lt;sub&gt;2&lt;/sub&gt; warms the atmosphere by several joules.   We can see this by estimating the added heat to the air and oceans as a result of climate change and comparing that to the energy use of all mankind.  I might add a crude calculation of my own later, but here's an &lt;a href=&quot;https://www.skepticalscience.com/waste-heat-global-warming.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;article that says the ratio of heat captured&lt;/a&gt; by man made climate change to waste heat has a ratio of 100 to 1.&lt;/p&gt;&#xA;&lt;p&gt;However you calculated it, the added heat by increases in CO&lt;sub&gt;2&lt;/sub&gt; exceeds any albedo variation by at least an order of magnitude, possibly two.   So even if Solar panels did absorb and retain more heat from sunlight than the surface area they cover, they still should lead to cooling by reducing the CO&lt;sub&gt;2&lt;/sub&gt; footprint.   The more important question is whether energy from solar panels can effectively reduce CO&lt;sub&gt;2&lt;/sub&gt; output from power-plants, because power-plants need to cover demand and solar energy can be intermittent.   Still, if there is any measurable reduction in fossil fuel generated electricity, there should be a net cooling due to how effective CO&lt;sub&gt;2&lt;/sub&gt; is in trapping heat even if the solar panels aren't efficient reflectors of sunlight.&lt;/p&gt;&#xA;&lt;p&gt;Also,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The way I understand the basics of global warming is we are putting to&#xA;much CO&lt;sub&gt;2&lt;/sub&gt; into the atmosphere which increases the size / density of&#xA;atmosphere shell.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is incorrect.  It's not the size or density of the atmosphere but it's opacity to the long-wavelength infrared light radiating from  the Earth that drives climate change.  (feedback mechanisms like melting ice and rising albedo play a role too), but changes in the Atmosphere's density or mass are largely irrelevant.&lt;/p&gt;&#xA;&lt;p&gt;Burning fossil fuels doesn't change the density or mass of the Atmosphere much anyway and they might even make the atmosphere a little lighter, though the overall calculation gets pretty complex with plant growth and oceanic absorption.&lt;/p&gt;&#xA;&lt;p&gt;When fossil fuels are burned, O&lt;sub&gt;2&lt;/sub&gt; is taken from the air, combined with hydrocarbons in the fuel which becomes CO&lt;sub&gt;2&lt;/sub&gt; and H&lt;sub&gt;2&lt;/sub&gt;0.  The net mass change of O&lt;sub&gt;2&lt;/sub&gt; lost and CO&lt;sub&gt;2&lt;/sub&gt; gained depends on the Carbon to Hydrogen ratio of the fuel burned, but the effect is pretty small either way.   High hydrogen fuels like Methane, the primary ingredient in natural gas, takes more O&lt;sub&gt;2&lt;/sub&gt; from the air by mass than it returns in CO&lt;sub&gt;2&lt;/sub&gt;.   More Carbon rich hydrocarbons like coal, the mass ratio is closer to even.   But in either case, the 30 plus billion tons of CO&lt;sub&gt;2&lt;/sub&gt; that's produced every year is negligible compared to the 5.1 million billion tons of the atmosphere.   That's less than 1 part in 100,000 by mass per year.&lt;/p&gt;&#xA;&lt;p&gt;What drives climate change is what happens to the long-wavelength infra-red light that leaves the Earth.   The longer wavelength photons that leave the Earth sometimes hit a molecule of CO&lt;sub&gt;2&lt;/sub&gt; that temporarily wiggles, before reflecting that light-energy back.   That's the basis of the Greenhouse effect.   The reflection back to the Earth of long wavelength infrared light.   Also, more CO&lt;sub&gt;2&lt;/sub&gt; means more IR light gets reflected, which adds heat to the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;In a nutshell it's the color of the sky, that is, color in wavelengths we can't see, so calling it color isn't quite right either, but that's the gist of the greenhouse effect.  Opacity not Density, though if you were to make Earth's atmosphere a lot more massive, say 10%-20%, that could have an effect, but we don't have the means to do that.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;sun rays enter the atmosphere then there is some reflection off the&#xA;earth and then the reflected rays get trapped within the atmosphere&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is generally true.  Reflectivity is an important aspect of &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_energy_budget&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth's energy budget&lt;/a&gt; and Albedo of a solar panel is one aspect of solar panel design.   That said, Solar panels cover such a small percentage of the Earth's surface, that their effect on reflection is negligible.   Also, reflected rays are less likely to get trapped in the atmosphere than infrared rays.   The Atmosphere is largely transparent to visible light and reflected rays of light are mostly in the visible spectrum.&lt;/p&gt;&#xA;&lt;p&gt;An interesting and related question to ask is, instead of installing solar panels, what if we paint things white (well, you might not want a white roof in winter, so that might not be a perfect solution) but in someplace where it's always warm/hot all year round and white roofs are common.  White paint would reflect more sunlight back into space than a typical solar panel would.   The math gets tricky where you have to weigh the fossil fuel use reduced against the increase in light reflected.  Here's an &lt;a href=&quot;https://blogs.scientificamerican.com/solar-at-home/the-albedo-effect/&quot; rel=&quot;nofollow noreferrer&quot;&gt;article that touches on that in some detail&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I also want to add that the dark color of solar panels is designed to absorb sunlight and turn it into electricity.  A reflective solar-panel kind of defeats the purpose, unless you're talking &lt;a href=&quot;https://en.wikipedia.org/wiki/Concentrated_solar_power&quot; rel=&quot;nofollow noreferrer&quot;&gt;concentrated solar power&lt;/a&gt; which works based on reflection, but those aren't typical solar panels, though they are solar energy.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2470" LastEditDate="2022-05-05T17:58:41.247" LastActivityDate="2022-05-05T17:58:41.247" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="12834" PostTypeId="2" ParentId="12828" CreationDate="2017-12-05T11:09:51.270" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The way I understand the basics of global warming is we are putting to much Co2 into the atmosphere which increases the size / density of atmosphere shell, sun rays enter the atmosphere then there is some reflection off the earth and then the reflected rays get trapped within the atmosphere.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Your understanding is incorrect. The greenhouse gases are more or less transparent in the visible portion of the spectrum. These greenhouse gases are anything but transparent in the thermal infrared. It is the responses of these gases to thermal infrared radiation rather than the responses to the visible portion of the electromagnetic spectrum that results in the greenhouse effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The outgoing radiation from a planet or moon has two key peaks, one in the visible / near infrared from reflected incoming sunlight, and the other in the thermal infrared from thermal radiation, the latter mostly from absorbed sunlight. The object is in thermal equilibrium when the energy from the incoming radiation from the Sun is in balance with the energy from the outgoing radiation (reflected sunlight and thermal radiation).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An atmosphere with greenhouse gases affects this dynamic in that the greenhouse gases absorb some of the thermal radiation coming from below, only to re-radiate it shortly after absorbing it. Some of this re-radiated thermal radiation goes upward, some downward. The downward radiation makes the planet's surface warmer than it would be without those greenhouse gases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some greenhouse warming is essential to life on Earth. The Earth would be a cold, barren place without the greenhouse effect. Just because some greenhouse warming is essential does not mean that more is better. Too much greenhouse warming is anything but a good thing.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What I was wondering if solar panels absorb the sun rays, is there then less of the suns rays reflected back into the atmosphere, or is some of the strength reduced ?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Strictly speaking, solar panels tilt the Earth's energy balance ever so slightly toward greater warming. Solar panels have a rather low albedo. This means they absorb more sunlight than do most other materials. Increasing the amount of absorbed sunlight means that there has to be an increase in outgoing thermal infrared to keep the energy equation balanced.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the portion of the Earth covered by solar panels is so minuscule that this theoretical effect is for all purposes a non-effect. Moreover, because solar panels produce electricity without emitting greenhouse gases, this theoretical negative effect becomes a positive effect when compared to producing electricity by burning fossil fuels.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-12-05T11:09:51.270" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12836" PostTypeId="1" CreationDate="2017-12-05T12:53:27.147" Score="3" ViewCount="64" Body="&lt;p&gt;The BBC article &lt;a href=&quot;http://www.bbc.com/news/world-asia-42219665&quot; rel=&quot;nofollow noreferrer&quot;&gt;Taiwan rainbow 'lasts record-breaking nine hours'&lt;/a&gt; also mentions that &lt;a href=&quot;https://en.wikipedia.org/wiki/Guinness_World_Records&quot; rel=&quot;nofollow noreferrer&quot;&gt;Guinness World Records&lt;/a&gt; lists six hours as the current record. See also Taiwan News &lt;a href=&quot;https://www.taiwannews.com.tw/en/news/3310942&quot; rel=&quot;nofollow noreferrer&quot;&gt;Taiwan shatters world record for longest-lasting rainbow&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Usually rainbows are on the opposite side of the sky from the Sun. We usually see them in the evening or morning.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can a rainbow be seen for nine or even six hours? &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;code&gt;Reported rainbow: 06:57 - 15:55,  30-Nov-2017, ~23.1° N (near Taipei, Taiwan)&lt;/code&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;code&gt;Official record: ~09:00 - ~15:00, 14-Mar-1994, ~53.9° N (near York, UK)&lt;/code&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2017-12-06T07:48:14.347" LastActivityDate="2017-12-06T07:48:14.347" Title="How could a 9 hour rainbow be possible?" Tags="|light|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12837" PostTypeId="1" CreationDate="2017-12-05T17:52:19.407" Score="0" ViewCount="1439" Body="&lt;p&gt;If the air temperature remains the same, will adding more sun reduce the amount of water vapor in the air - that is, does the sun have any impact on water vapor in the air when temperature is removed as a variable?&lt;/p&gt;&#xA;" OwnerUserId="11740" LastEditorUserId="6467" LastEditDate="2017-12-05T23:26:37.840" LastActivityDate="2021-08-10T17:40:47.073" Title="Sun's Effect on Water Vapor in the Air" Tags="|sun|evaporation|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12838" PostTypeId="1" AcceptedAnswerId="12839" CreationDate="2017-12-05T18:16:00.213" Score="1" ViewCount="301" Body="&lt;p&gt;If anyone could work out how much mass (not weight :) ) have humanity added to the Earth, seeing that the LHC (atlas, I believe, weighs 7000 tonnes), and the Three Gorges dam in China slowed the Earth's rotation by 0.06 micrometers. How much does the collective building of humanity added to the mass of the Earth?&lt;/p&gt;&#xA;" OwnerUserId="11741" LastActivityDate="2017-12-12T20:47:21.943" Title="How much mass has humanity added to the planet?" Tags="|human-influence|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12839" PostTypeId="2" ParentId="12838" CreationDate="2017-12-05T19:18:30.677" Score="10" Body="&lt;p&gt;All mass used in construction on Earth comes from material on Earth.  Since mass is conserved, there is no change.  If we start harvesting material from the moon or asteroids for use in construction on Earth, then there would be a net increase in mass.  But currently, the net mass of Earth has decreased due to man, since we have launched many satellites into space which came from material on Earth.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-12-05T19:18:30.677" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="12840" PostTypeId="2" ParentId="7714" CreationDate="2017-12-05T20:11:20.193" Score="1" Body="&lt;p&gt;If you check the 6-hourly products in the links you shared, you can see that CFSR includes 50 variables in the &quot;complete&quot; dataset. The hourly dataset has a limited number of variables (25 in total). That's what they mean by &quot;selected&quot;. Hope this help.&lt;/p&gt;&#xA;" OwnerUserId="11744" LastActivityDate="2017-12-05T20:11:20.193" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12841" PostTypeId="1" AcceptedAnswerId="12844" CreationDate="2017-12-06T00:59:18.490" Score="3" ViewCount="89" Body="&lt;p&gt;I am looking for a tool to sketch changes to Earth. It should start with a geoid or an Earth model, rise/lower/flood selected areas. &quot;Heal&quot; boardersk: if an island is added in an ocean height shouldn't abruptly change from 0 $m$ to $-$1000 $m$. It should also measure distances between points, allow labeling and export maps of selected images as raster graphics (jpg image). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far I could do two things:  &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Start with Google Earth, prepare necessary shapes using flooding, paste results as layers in Gimp/Photoshop [fast and ugly]&lt;/li&gt;&#xA;&lt;li&gt;Import data in Matlab, define rules for modified regions, export [manual rule definitions is slow, no way to smart select, drag and drop regions] &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;What is the standard approach to do this? For instance, how people display flood plains, draft a channel or a new island project?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Windows/Mac/Linux/doesn't_matter? Windows preferred, Linux is OK. &#xA;GUI or also command line? GUI, or GUI+CLI batching. CLI only is undesired.&#xA;Go you want to use a GIS? I didn't know about GIS. Looking into in.&lt;/p&gt;&#xA;" OwnerUserId="11745" LastEditorUserId="11745" LastEditDate="2017-12-14T15:25:43.317" LastActivityDate="2017-12-14T15:25:43.317" Title="Software to draw maps based on Earth" Tags="|mapping|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12843" PostTypeId="2" ParentId="12837" CreationDate="2017-12-06T08:52:38.143" Score="4" Body="&lt;p&gt;You need to define what you mean by 'adding more sun'. I'm asuming you mean 'increase the solar constant'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The amount of water vapour in the air is, as a first order approximation, related to temperature - &lt;a href=&quot;https://www.scientificamerican.com/article/global-warming-and-the-science-of-extreme-weather/&quot; rel=&quot;nofollow noreferrer&quot;&gt;every degree of temperature rise gives us 7% more water vapour&lt;/a&gt;.  So if 'adding more sun' increases the temperature then it automatically increases water vapour. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, to add more sun without increasing the temperature, you'd have to compensate by doing something like painting large areas of land white; this would increase the Earth's &lt;a href=&quot;https://en.wikipedia.org/wiki/Albedo&quot; rel=&quot;nofollow noreferrer&quot;&gt;albedo&lt;/a&gt;, reflecting the extra solar radiation. No temperature change overall, so no water vapor change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only direct effect of the sun on water vapor is something entirely different - through &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/JC074i023p05355/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;photo-dissociation&lt;/a&gt;. This is where the sun's UV rays directly break up water molecules.  However, in order to have an appreciable effect on the day to day concentration of water vapour, you'd need to replace the Sun with a much bigger and hotter star that blasted out far more UV radiation. The problem here is that everyone would die.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So as far as the question can be answered, it would be no under any realistic scenario.&lt;/p&gt;&#xA;" OwnerUserId="8217" LastActivityDate="2017-12-06T08:52:38.143" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12844" PostTypeId="2" ParentId="12841" CreationDate="2017-12-06T09:04:27.363" Score="1" Body="&lt;p&gt;The most common software for creating and modifying maps is ArcGIS (commercial but you can get free trial for a month) or QGIS (open source).&lt;/p&gt;&#xA;" OwnerUserId="11156" LastActivityDate="2017-12-06T09:04:27.363" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12846" PostTypeId="2" ParentId="12812" CreationDate="2017-12-06T16:44:17.563" Score="1" Body="&lt;p&gt;It depends where you live as laws verry from country to country. Just ask your local lawyer or law enforcement official. It may also depend on what data you are recording&lt;/p&gt;&#xA;" OwnerUserId="11751" LastActivityDate="2017-12-06T16:44:17.563" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12847" PostTypeId="2" ParentId="12801" CreationDate="2017-12-06T16:47:23.347" Score="0" Body="&lt;p&gt;Yes, ever tried a vinegar and baking soda reaction, well that reaction produces a little water along with Products. One of the products is sodium acetate (NaC2H3O2). The other products are water(H2O) and carbon dioxide (CO2).&lt;/p&gt;&#xA;" OwnerUserId="11751" LastActivityDate="2017-12-06T16:47:23.347" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12848" PostTypeId="1" AcceptedAnswerId="12854" CreationDate="2017-12-06T18:28:02.750" Score="2" ViewCount="257" Body="&lt;p&gt;From noaa.gov's &lt;em&gt;Ocean facts&lt;/em&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;h1&gt;Salt in the &lt;a href=&quot;https://oceanservice.noaa.gov/facts/whysalty.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ocean&lt;/a&gt; comes from rocks on land.&lt;/h1&gt;&#xA;  &#xA;  &lt;p&gt;The rain that falls on the land contains some dissolved carbon dioxide from the surrounding air. This causes the rainwater to be slightly acidic due to carbonic acid (which forms from carbon dioxide and water).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;But&lt;/em&gt;...if this is the case wouldn't our rivers be even saltier from seasonal downpours and snowpack melt? &lt;/p&gt;&#xA;" OwnerUserId="11565" LastEditorUserId="595" LastEditDate="2017-12-07T07:47:02.357" LastActivityDate="2023-07-27T08:24:35.480" Title="Is this why oceans are salty?" Tags="|ocean|geochemistry|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12849" PostTypeId="2" ParentId="12848" CreationDate="2017-12-06T18:54:39.800" Score="6" Body="&lt;p&gt;No, because fresh rainfall has no salt in it, so as long as the river keeps moving the salt has no time to accumulate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Only stagnant sources of water on land, like lakes with no outlet, can become saline.&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2017-12-06T18:54:39.800" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12850" PostTypeId="1" CreationDate="2017-12-06T18:57:06.950" Score="3" ViewCount="2876" Body="&lt;p&gt;I used to live in San Diego and I remember the occasional wild fire; My dad standing on the roof, watering it with a garden hose.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have lived in New England, however, for the last 40 years and have not seen a wild fire yet. Why not? Just too wet here?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2017-12-12T06:02:02.643" Title="Why are there no wild fires in New England?" Tags="|fire|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12852" PostTypeId="2" ParentId="12850" CreationDate="2017-12-07T02:55:04.103" Score="6" Body="&lt;h1&gt;Its just too wet there&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Generally, fires don't happen where it is wet. Here is a map of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Pre-Columbian_savannas_of_North_America#/media/File:Wildland_Fire_in_Ecosystems_15-1-2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;fire regime&lt;/a&gt; in Pre-Columbian America: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/11yuI.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/11yuI.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Northern New England gets practically no fires, with a fire frequency of every 200 years or longer. Southern New England sees more frequent fires, maybe ever 40 years, but those fires are typically &lt;a href=&quot;https://en.wikipedia.org/wiki/Understory&quot; rel=&quot;nofollow noreferrer&quot;&gt;understory&lt;/a&gt; only. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a region to be fire resistant, it must meet two criteria: it must be &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Humid_climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;'humid'&lt;/a&gt; and it must be 'humid' year-round. New England meets both of these criteria. Here is a map of precipitation versus evapotranspiration for the US:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EAjAU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EAjAU.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note the areas in green have more water falling from the sky than returning to it via evaporation and transpiration. New England is one of the wettest parts of the nation by this metric. There is plentiful rain/snow, generally heavy cloud cover, and relatively low temperatures to reduce evaporation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The last piece is being wet all year. By looking at &lt;a href=&quot;https://www.usclimatedata.com/climate-graph.php?id=usma0046&amp;amp;system=american&amp;amp;title=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Boston's&lt;/a&gt; climate data, we can see that Boston's precipitation is evenly distributed throughout the year. &lt;/p&gt;&#xA;" OwnerUserId="6703" LastEditorUserId="6298" LastEditDate="2017-12-11T10:38:11.663" LastActivityDate="2017-12-11T10:38:11.663" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12853" PostTypeId="1" CreationDate="2017-12-07T16:39:19.757" Score="4" ViewCount="101" Body="&lt;p&gt;Question is in the title.  I'm doing impacts research and need to pick a couple of scenarios before downloading GCM runs.  Want to pick a low one and a high one and one in the middle of the road.  I'm an economist, rather than a climate scientist.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In my experience, HadGEM has been fairly pessimistic.  But I'd appreciate a reference to something citable, ideally plotting climate sensitivity by model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To add, I'll be downloadading a few of several model runs from a dataset of publicly available downscaling experiments.  I'll then analyze each climate model, and then average the results of each experiment to form an ensemble. It is known that one should not average GCM runs until the final step in one's analysis.&lt;/p&gt;&#xA;" OwnerUserId="545" LastEditorUserId="545" LastEditDate="2017-12-11T13:26:55.233" LastActivityDate="2017-12-11T13:26:55.233" Title="Which CMIP5 models give the highest and lowest warming for RCP8.5?" Tags="|climate-change|climate-models|reference-request|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12854" PostTypeId="2" ParentId="12848" CreationDate="2017-12-07T16:48:13.637" Score="2" Body="&lt;p&gt;In terms of concentration, I would say no. With higher rainfall and snowpack melt, you will have more solute and therefore a greater ability to dissolve saline species. However, you also have more water so the concentration of salts in the rivers shouldn't show a dramatic change (unless the river begins to run through a salt flat or something like that). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To make the rivers more saline, you would need to change other factors such as temperature, pressure, and input/output from the system. Since we're working with a river, pressure remains relatively constant at atmospheric conditions. For the relevant temperatures (0 C - 30 C), the solubility of NaCl in water changes from 35.65 g NaCl/100 mL water to 36.09 g NaCl/100 mL water. That's a ~1.2% change, which means temperature does not have a large effect over that range. This leaves us with the input and output from the system. Without an outlet, the water level will fluctuate between the effects of input and evaporation. Meanwhile, the salinity will only increase as more salt species are dissolved and introduced. Therefore, as long as the river keeps moving, its salinity will not change significantly.&lt;/p&gt;&#xA;" OwnerUserId="11739" LastActivityDate="2017-12-07T16:48:13.637" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12855" PostTypeId="1" CreationDate="2017-12-07T23:35:50.060" Score="4" ViewCount="897" Body="&lt;p&gt;I'm a mathematics professor who is seeking to find interesting, application-driven ways of teaching freshmen college students differential/integral calculus. I am in no way versed in crystallography or much of earth science beyond the usual education that the average non-expert gets, but I did enjoy and do well in a single-semester college geology course, and rocks and minerals have always fascinated me. I am wondering if the crystallographers and earth scientists here might know off-hand applications of tangent lines, derivatives, optimization, integration, etc., in crystallography. I've been browsing, and it certainly seems that vectors and linear algebra and group theory are central in this field, but it has been difficult to find uses for undergraduate calculus skills in the field. Please help?&lt;/p&gt;&#xA;" OwnerUserId="11758" LastActivityDate="2017-12-08T01:24:44.290" Title="Applications of differential/integral calculus in crystallography (teaching undergraduates)?" Tags="|crystallography|crystals|teaching|mathematics|education|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12856" PostTypeId="2" ParentId="12855" CreationDate="2017-12-08T01:24:44.290" Score="1" Body="&lt;p&gt;This &lt;a href=&quot;http://shearsensibility.blogspot.com/2008/09/geoscience-uses-for-calculus-and-beyond.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;site&lt;/a&gt; may give you some ideas. In particular, look at the Petrology and Geochemistry section:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Metamorphic phase diagrams show which minerals are stable under&#xA;  various temperatures and pressures. The slopes of the boundaries&#xA;  between the areas where different minerals are stable depend on the&#xA;  properties of the minerals (like the entropy and the molar volume).&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;And... well, mineralogy, petrology, and geochemistry are full of ideas&#xA;  taken from chemical thermodynamics. And thermodynamics is full of&#xA;  multivariable calculus. (How does changing the pressure change the&#xA;  amount of calcium in garnet vs the amount of calcium in plagioclase?&#xA;  The question is a partial derivative.) From my own favorite,&#xA;  metamorphic petrology, there are all kinds of techniques for using&#xA;  metamorphic minerals to tell stories of heating and burial and cooling&#xA;  and exhumation. And none of the techniques would be possible without&#xA;  calculus. (Or, in many cases, differential equations.) I'm sure&#xA;  igneous rocks and ore deposits have similar uses of thermodynamics.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Here's an example of a metamorphic P-T Diagram with the source link with more examples:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KscLX.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KscLX.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source:  &lt;a href=&quot;https://serc.carleton.edu/research_education/equilibria/metamorphic_diagrams.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://serc.carleton.edu/research_education/equilibria/metamorphic_diagrams.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2017-12-08T01:24:44.290" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12857" PostTypeId="2" ParentId="2845" CreationDate="2017-12-08T18:40:19.387" Score="1" Body="&lt;p&gt;Do you know the (TVD) true vertical depth of these wells.  Are you certain the wells are tapped into an oil formation.  Oil wells deplete in the production sense but the mess still remains as well over time oil will seep back into the fractured zone. The clean up and maintenance of equipment would be great. There may also be the presence of other toxic gases such as h2s. Think of a oil spill on land or ocean and the coast of cleaning it up. In my opinion I be very impractical and coastly. In most cases impossible because of the differences in   &lt;a href=&quot;https://maps.nrel.gov/geothermal-prospector/?aL=ZbqxrS%255Bv%255D%3Dt&amp;amp;bL=groad&amp;amp;cE=0&amp;amp;lR=0&amp;amp;mC=59.88893689676585%2C-72.94921875&amp;amp;zL=3&quot; rel=&quot;nofollow noreferrer&quot;&gt;formations&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.oit.edu/docs/default-source/geoheat-center-documents/geothermal-direct-use.pdf?sfvrsn=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Case studies strictly geothermal&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://openei.org/wiki/Category:Geothermal_References&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geothermal Well References &lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11565" LastActivityDate="2017-12-08T18:40:19.387" CommentCount="0" CommunityOwnedDate="2017-12-08T18:40:19.387" ContentLicense="CC BY-SA 3.0" />
  <row Id="12858" PostTypeId="1" AcceptedAnswerId="12864" CreationDate="2017-12-08T19:29:33.660" Score="3" ViewCount="85" Body="&lt;p&gt;I'm looking for illuminating and fun weather data visualizations like e.g. &lt;a href=&quot;https://earth.nullschool.net&quot; rel=&quot;nofollow noreferrer&quot;&gt;EarthWindMap&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More specifically, I was hoping to find wind vectors overlayed onto a prognostic chart to visualize how the wind moves around pressure systems and fronts.&lt;/p&gt;&#xA;" OwnerUserId="11761" LastEditorUserId="192" LastEditDate="2017-12-11T14:29:25.487" LastActivityDate="2017-12-11T14:29:25.487" Title="Looking for fun and illuminating weather visualizations" Tags="|meteorology|wind|weather-forecasting|visualization|weather-satellites|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12859" PostTypeId="1" AcceptedAnswerId="12860" CreationDate="2017-12-08T22:22:54.780" Score="1" ViewCount="997" Body="&lt;p&gt;&lt;strong&gt;[Update: This was not a duplicate of the other question since the mountain shape is rather different. This was already stated in my question below.]&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This question is a bit similar to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/12011/how-could-this-pyramidal-mountain-have-been-formed&quot;&gt;this other question&lt;/a&gt; about pyramid-shaped mountains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this case though the mountain is also in Antarctica but it looks as shown in below picture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jkDBp.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jkDBp.jpg&quot; alt=&quot;antarctic mountain&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(This picture is taken at &lt;a href=&quot;https://en.wikipedia.org/wiki/Princess_Elisabeth_Antarctica&quot; rel=&quot;nofollow noreferrer&quot;&gt;Princess Elisabeth station&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I was curious on if this mountain in the foreground, and the one behind it, could be volcanoes? Or are there examples where non-volcano mountains form into these shapes?&lt;/p&gt;&#xA;" OwnerUserId="11762" LastEditorUserId="11762" LastEditDate="2017-12-09T21:01:08.827" LastActivityDate="2017-12-09T21:01:08.827" Title="How could this &quot;aztec temple&quot; mountain (or volcano) have been formed on Antarctica?" Tags="|mountains|antarctic|" AnswerCount="1" CommentCount="3" ClosedDate="2017-12-10T22:42:28.823" ContentLicense="CC BY-SA 3.0" />
  <row Id="12860" PostTypeId="2" ParentId="12859" CreationDate="2017-12-09T04:03:29.127" Score="3" Body="&lt;p&gt;Remember that Antarctica is covered in a sheet of ice. Strip away the ice and you get something like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hPk50.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hPk50.jpg&quot; alt=&quot;Matterhorn&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(Source:Wikimedia Commons)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the &lt;strong&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Matterhorn&quot; rel=&quot;nofollow noreferrer&quot;&gt;Matterhorn&lt;/a&gt;&lt;/strong&gt; in the Alps on the Swiss-Italian border. The word &lt;strong&gt;&lt;em&gt;horn&lt;/em&gt;&lt;/strong&gt; is used in glacial geomorphology to refer to a mountain peak that has been ground by glaciers on many sides to create a &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Pyramidal_peak&quot; rel=&quot;nofollow noreferrer&quot;&gt;pyramidal peak&lt;/a&gt;&quot; with sheer, faceted sides.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During the Pleistocene ice ages, the Alps were covered in an ice sheet much like Antarctica is today, and undoubtedly at some point the tip of the Matterhorn poked through the top of the ice, looking very similar to the mountain in your picture. &lt;/p&gt;&#xA;" OwnerUserId="6467" LastActivityDate="2017-12-09T04:03:29.127" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12863" PostTypeId="1" CreationDate="2017-12-10T03:02:57.350" Score="0" ViewCount="85" Body="&lt;p&gt;![enter image description here]Arizona desert wash&#xA;A very heavy rocking have a few and when busted open beautiful veins of dark silver sometimes yellow gold.light pink and teal looking(&lt;a href=&quot;https://i.stack.imgur.com/HRJgq.jpg)white&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://i.stack.imgur.com/HRJgq.jpg)white&lt;/a&gt; semi round .very heavy&lt;img src=&quot;https://i.stack.imgur.com/5BLcL.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bZM8d.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="11766" LastEditorUserId="1149" LastEditDate="2017-12-11T15:22:49.400" LastActivityDate="2017-12-11T15:22:49.400" Title="What type of minerals exist in this rock?" Tags="|geology|" AnswerCount="1" CommentCount="1" ClosedDate="2019-09-16T02:48:40.603" ContentLicense="CC BY-SA 3.0" />
  <row Id="12864" PostTypeId="2" ParentId="12858" CreationDate="2017-12-10T03:39:33.457" Score="1" Body="&lt;p&gt;Try &lt;a href=&quot;http://www.windy.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Windy.com&lt;/a&gt;  It looks very similar to the EarthWindMap, but appears to offer more controls.  It is simple to change the heights and what variables are of interest.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/m9a4G.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/m9a4G.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-12-10T03:39:33.457" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12865" PostTypeId="1" AcceptedAnswerId="12867" CreationDate="2017-12-10T12:05:37.133" Score="1" ViewCount="173" Body="&lt;p&gt;A diagram in a book I have places Archaic and Proterozoic under &quot;eras&quot;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is such naming correct? ICS says they are eons, so do most sources I could find, but a 1979 volume of &quot;Treatise on Invertebrate Paleontology&quot; seems to name at least Proterozoic as an era.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is applying the term &quot;era&quot; here en error? Obsolete usage, once popular, but now generally abandoned? Or perhaps a rare, but correct and accepted, convention?&lt;/p&gt;&#xA;" OwnerUserId="4652" LastActivityDate="2017-12-10T15:45:53.463" Title="Can we call the Precambrian eons (i.e. Archaic and Proterozoic) eras?" Tags="|geology|stratigraphy|precambrian|era|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12866" PostTypeId="1" AcceptedAnswerId="12890" CreationDate="2017-12-10T13:00:27.250" Score="1" ViewCount="258" Body="&lt;p&gt;In the United States the National Weather Service (NWS) Storm Prediction Center (SPC) now has 5 categories for the threat of severe storms.  These five categories replaced the previous three categories of slight, moderate, and high risk in October 2014.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qBloq.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qBloq.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://www.spc.noaa.gov/new/images/Outlook-category-descriptions.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.spc.noaa.gov/new/images/Outlook-category-descriptions.png&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first time I heard our local station talking about slight, marginal, and enhanced risk I had no idea which was worse- nor did anybody else around me at the time.  After doing some research I understand the differences but still don't necessarily remember which is worse, whereas the previous slight, moderate, and high risk categories were pretty much self explanatory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What additional meteorological information is presented in the additional categories that may affect how the general public reacts to the threat?  I'm also wondering how these categories compare to the information given in other countries?&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastEditorDisplayName="user11318" LastEditDate="2017-12-14T11:50:13.880" LastActivityDate="2017-12-14T11:50:13.880" Title="Severe storm predictions: What meteorological considerations go into hazard assessments?" Tags="|meteorology|storms|" AnswerCount="1" CommentCount="8" ClosedDate="2017-12-13T14:16:55.590" ContentLicense="CC BY-SA 3.0" />
  <row Id="12867" PostTypeId="2" ParentId="12865" CreationDate="2017-12-10T15:36:13.610" Score="3" Body="&lt;p&gt;It is and is not an an error depending on how it is used. They are Eons but in older literature they were also, sort of, eras as the Eons were not subdivided as they are now. Especially in literature dealing with the transitions they might refer to them indirectly as eras, such as &quot;In the previous Proterozoic era&quot;, proterozoic being possessive. At the time this was technically sloppy but not a big issue, but now that they are subdivided this would be incorrect to do now. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You also have the issue of plurality in older literature. Spelling can vary from country to country and Paleontology is very much a international discipline. Occasionally in older literature Era can sometimes be used as the plural for Era (like sheep and sheep), so a reference to the Proterozoic era may be referring to the multiple eras &lt;em&gt;in&lt;/em&gt; the Proterozoic. Again technically sloppy but in the time before electronic word processing a spelling error that might be ignored.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;in a time scale they be grouped with era, as eons were often not included, and again they had no named eras in them. If the diagram included eons however this would be incorrect, but was sometimes done to conserve space since otherwise you would have a large blank section in all the smaller subdivisions to make room for fitting them in the eons, technically wromg but often ignored.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Without knowing the context of usage it is hard to say whether it is an error.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2017-12-10T15:45:53.463" LastActivityDate="2017-12-10T15:45:53.463" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12868" PostTypeId="2" ParentId="12863" CreationDate="2017-12-10T16:01:42.127" Score="2" Body="&lt;p&gt;It is massive white quartz also referred to as milky quartz, the streaks are  trace impurities and can occasionally include valuable metals like gold but just as often included fools gold (pyrite). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This chat can help with more detailed identification of trace metals &lt;a href=&quot;https://www.mindat.org/mesg-11-219962.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.mindat.org/mesg-11-219962.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/q8ZvX.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/q8ZvX.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2017-12-10T16:01:42.127" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12871" PostTypeId="2" ParentId="12858" CreationDate="2017-12-11T09:07:41.147" Score="1" Body="&lt;p&gt;Try &lt;a href=&quot;http://www.ventusky.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;VentuSky&lt;/a&gt;. An interactive map with different models and data visualization that can be adjusted easily.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastActivityDate="2017-12-11T09:07:41.147" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12872" PostTypeId="1" AcceptedAnswerId="13933" CreationDate="2017-12-11T09:53:40.857" Score="8" ViewCount="200" Body="&lt;p&gt;Deep impact ejecta on the moon seem to indicate that the moon's mantle is predominantly 'low-calcium pyroxene' (recent letter to Nature), whereas the Earth's mantle (or at least the upper mantle) is dominantly olivine with only ~15% pyroxenes. So how can this discrepancy arise if the Earth and moon have a common origin? The only possibility I can think of is if partial fractionation of magnesium silicates actually took place &lt;em&gt;in space&lt;/em&gt;, before falling to either Earth or moon, with the slightly denser olivine falling to the higher gravity of Earth, and less dense pyroxene falling to the lower gravity proto-moon. Is this possible? Is there any isotopic evidence of Earth-moon mantle commonality?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2018-04-18T20:35:36.167" Title="Earth and moon have different mantle compositions. Is this a fatal flaw in the 'Giant Impact hypothesis'?" Tags="|earth-history|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12873" PostTypeId="2" ParentId="12838" CreationDate="2017-12-11T10:57:30.967" Score="7" Body="&lt;p&gt;Don't confuse redistribution of mass with gain/loss of mass. There's a net loss of hydrogen and helium from the uppermost tenuous atmosphere. This far outweighs the incoming meteorites and miscellaneous space dust - by some 50,000 to 90,000 tonnes per year. Both of these components eclipse, by orders of magnitude, the loss of mass from radioactive decay, satellites that drift into space, recovered moon rocks, and assorted other human activities. &#xA;The exception to losing mass may be those rare years when large bodies collide with Earth, in which case there will be anomalous net gains in mass. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="11741" LastEditDate="2017-12-12T20:47:21.943" LastActivityDate="2017-12-12T20:47:21.943" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12874" PostTypeId="2" ParentId="12853" CreationDate="2017-12-11T12:09:32.550" Score="2" Body="&lt;p&gt;There is no model that consistently yields either highest or lowest warming because each model has strengths and weaknesses which depend upon the conceptual emphases. This varies with latitude, continentality, proximity of water/lakes, presence/absence of ice and mountains, regional significance of atmospheric processes - both physical and chemical, regional airflow strengths such as monsoonal and hurricanes, etc. Each model calibration works either brilliantly well, or downright dubiously, according to the model conceptualization. There is no 'one size fits all' (environments). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, however, I routinely use the CMIP-5 ensemble as listed in the World Bank Climate Change Knowledge Portal - just because it is convenient and readily available. You can find it at &lt;a href=&quot;http://sdwebx.worldbank.org/climateportal/index.cfm&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://sdwebx.worldbank.org/climateportal/index.cfm&lt;/a&gt; - just click on the world map for your region / country / area of interest, and select the parameters you want. This is not the full ensemble, but 16 selected models that seem to work well - at least most of the time. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So here is a recent example from Nepal: scanning the maximum and minimum monthly temperatures, 'giss-r' generally yielded the hottest temperatures, although for occasional months the hottest was 'ccsm-4'. The coolest temperatures were mostly given by 'noresm 1-m' though for occasional months the coldest was from 'miroc esm'. However, this is just a random example. I do not believe that such conclusions are consistent everywhere in the world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why concentrate on the coolest and hottest models? Doesn't it make more sense to work with the ensemble median? I find that the relative distribution of model results is roughly similar regardless of the RCP. I usually quote RCP 4.5 or 6.0. RCP 8.5 is too pessimistic. Does anyone still seriously think that RCP 2.8 is attainable?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My advice is to spend a day picking temperature trends from the WB-CMIP model portal for a wide range of environments, and only then draw your conclusions. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2017-12-11T12:09:32.550" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12876" PostTypeId="1" CreationDate="2017-12-11T17:45:17.850" Score="3" ViewCount="108" Body="&lt;p&gt;I am interested in becoming a geophysicist. I am currently doing my undergraduate degree in the UK but have not chosen a specialisation. Is it better to specialise in Earth Sciences as an undergrad or go with Physics?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I like quantitative fields but I feel that undergraduate Earth Sciences does not offer such quantitative aspects. I also really like physics but feel that applying it in the context of the earth is really interesting. As becoming a geophysicist would probably require me to go to grad school, would an undergrad degree in Earth Sciences or Physics better prepare me to study Geophysics in grad school?&lt;/p&gt;&#xA;" OwnerUserId="11771" LastActivityDate="2017-12-13T12:40:16.870" Title="Aspiring Geophysicist" Tags="|geophysics|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12877" PostTypeId="1" AcceptedAnswerId="12918" CreationDate="2017-12-11T18:34:14.983" Score="2" ViewCount="60" Body="&lt;p&gt;I've been reading a paper&lt;sup&gt;(*)&lt;/sup&gt; looking at the deep carbon cycle and it mentions a key process that the authors refer to as &quot;redox melting&quot;. According to the paper, reducing conditions increase the melting point of the rocks at depth, which affects partial melting. Can anyone explain why the redox state has an impact on the melting point?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;(*)&lt;/sup&gt; Foley &amp;amp; Fischer (2017) &lt;a href=&quot;http://dx.doi.oorg/10.1038/s41561-017-0002-7&quot; rel=&quot;nofollow noreferrer&quot;&gt;An essential role for continental rifts and lithosphere in the deep carbon cycle&lt;/a&gt;, &lt;em&gt;Nature Geoscience&lt;/em&gt; 10, 897–902&lt;/p&gt;&#xA;" OwnerUserId="11739" LastEditorUserId="725" LastEditDate="2017-12-15T23:25:39.277" LastActivityDate="2017-12-15T23:25:39.277" Title="Effect of reducing conditions on melting point" Tags="|geochemistry|petrology|carbon-cycle|igneous|mantle-plumes|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12879" PostTypeId="2" ParentId="12850" CreationDate="2017-12-12T06:02:02.643" Score="2" Body="&lt;p&gt;According to the &lt;a href=&quot;https://www.predictiveservices.nifc.gov/intelligence/2016_Statssumm/fires_acres16.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;NIFC report for 2016&lt;/a&gt;, there were approximately 1000 acres of wildfire burned in Massachusettes and Maine each.  That is much smaller than California, which saw 560,000 acres burn in wildfires. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are wildfires in New England.  They are just smaller in comparison to the rest of the country.  This is largely due to the moisture of fuels and thus fire spread is less dramatic.  &lt;a href=&quot;https://en.wikipedia.org/wiki/Boston#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;New England's climate&lt;/a&gt; is such that there is consistent rain throughout the year, so fuels do not dry out in the summer so badly like in the west and south.   See the image below from the research report &quot;&lt;a href=&quot;https://www.urban.org/sites/default/files/publication/77201/2000593-Wildfires-in-the-United-States-A-Primer.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wildfires in the United States&lt;/a&gt;&quot; and notice the geographic distribution:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XmTvO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XmTvO.png&quot; alt=&quot;Wildfires in the United States&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2017-12-12T06:02:02.643" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12880" PostTypeId="2" ParentId="12876" CreationDate="2017-12-12T11:07:41.140" Score="3" Body="&lt;p&gt;How flexible is your degree? I would suggest doing earth sciences with as many quantitative electives as possible. In grad school, you will have the chance to make up for any missing knowledge or skills you have, either by self study or by taking courses.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-12-12T11:07:41.140" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12882" PostTypeId="2" ParentId="12876" CreationDate="2017-12-12T14:33:45.940" Score="5" Body="&lt;p&gt;I would recommend to do an undergraduate in physics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I work at a department of Meteorology.  When faculty hire a new PhD student or postdoc, they often prefer those with an undergraduate in Physics than with an undergraduate in Meteorology.  The Physics degree gives a better preparation for doing science.  It has more maths and physicists are more likely to have some programming experience than meteorologists.  For most scientific positions, such programming experience is highly valuable.  It appears the meteorologists are more likely to end up in jobs like weather forecasting or energy trading, rather than science.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although this experience may be quite localised, a physics undergraduate degree does give you a more generic background.  It's easier to catch up on the specifics of geophysics when you have a physics background, than the other way around.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2017-12-13T12:40:16.870" LastActivityDate="2017-12-13T12:40:16.870" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12884" PostTypeId="1" CreationDate="2017-12-12T20:56:57.583" Score="6" ViewCount="513" Body="&lt;p&gt;I am broadly familiar with the concept of numerical weather prediction models using various finite methods to solve the primitive equations used in these models, but how do spectral methods work, generally speaking? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the basic differences between NWP models using &quot;traditional&quot; finite-difference or finite volume methods and those that employ spectral method approaches?&lt;/p&gt;&#xA;" OwnerUserId="662" LastActivityDate="2017-12-12T22:33:18.130" Title="How do spectral methods work in the context of numerical weather prediction models?" Tags="|meteorology|weather-forecasting|numerical-modelling|nwp|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12886" PostTypeId="2" ParentId="12884" CreationDate="2017-12-12T22:33:18.130" Score="8" Body="&lt;p&gt;Presume that the atmosphere can be modeled with waves of different frequencies. Therefore, the atmosphere can be written as a series of sine and cosine functions with different frequencies and coefficients. Consider the linear advection equation: $$\frac{\partial u}{\partial t}= -c \frac{\partial u}{\partial x}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider the assumption that $u$ can be modeled as $$u=\sum^\infty_{|n|=0} A_n(t)\exp(i\omega_n x) $$ But since we have limited computational resources, $$u=\sum^N_{|n|=0} A_n(t)\exp(i\omega_n x) $$ Therefore, our advection equation becomes $$\sum^\infty_{|n|=0} \frac{d A_n(t)}{dt}\exp(i\omega_n x)=-c\sum^\infty_{|n|=0} i \omega_n A_n(t)\exp(i\omega_n x) $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we integrate this equation and leverage the orthogonal properties of sine and cosine, $$\int^L_0 \sum^\infty_{|n|=0} \frac{d A_n(t)}{dt}\exp(i\omega_n x)\exp(i\omega_m x)dx=-c\int^L_0 \sum^\infty_{|n|=0} i \omega_n A_n(t)\exp(i\omega_n x)\exp(i\omega_m x)dx$$ Then the summation notation can be removed. $$\frac{d A_m(t)}{dt}=-ic \omega_m A_m(t)$$ Now this &lt;em&gt;can&lt;/em&gt; be solved analytically, and as such we do have an analytic solution to the advection equation, but what we can do to model this numerically, is combine the finite difference notation and the spectral solution to numerically integrate the advection equation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, $$u_{n+1}= u_n -c\Delta t\sum^\infty_{|l|=0} i \omega_l A_l(t)\exp(i\omega_l x) $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to summarize, &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Assume that the variable can be expressed as a sum of basis functions, commonly sine and cosine functions.&lt;/li&gt;&#xA;&lt;li&gt;Create a truncated series (fourier series), creating an analytic expression for said quantity.&lt;/li&gt;&#xA;&lt;li&gt;Evaluate the derivative of the truncated series, and replace the derivative (often computed with finite difference approximations) with the analytic representation of the derivative.&lt;/li&gt;&#xA;&lt;li&gt;Numerically integrate in time.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Now there are plenty of limitations, such as the nonlinear version of that equation. If I had my notes on hand, then I could address those problems more. I'll edit this when I can. Also, model physics cannot be computed in spectral space, so there has to be conversion from spectral to physical space and vice-versa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll check my notes and correct any errors I can find later.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2017-12-12T22:33:18.130" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12888" PostTypeId="1" CreationDate="2017-12-13T08:22:40.523" Score="3" ViewCount="48" Body="&lt;p&gt;I am working on a shipping company and we have several applications to calculate the distance between two ports. My curiosity was triggered by the fact that, time by time I see a small change on the distance. For example, when the distance was 2000 miles it changed to 2003 miles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I searched if there was any infrastructure changes on the port but my search came back negative.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How could this addition on miles be explained?&lt;/p&gt;&#xA;" OwnerUserId="11782" LastActivityDate="2017-12-13T08:22:40.523" Title="Change on naval distances" Tags="|oceanography|" AnswerCount="0" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="12890" PostTypeId="2" ParentId="12866" CreationDate="2017-12-13T13:43:14.630" Score="3" Body="&lt;p&gt;The SPC's &lt;a href=&quot;http://www.spc.noaa.gov/exper/dy1-3example/&quot; rel=&quot;nofollow noreferrer&quot;&gt;changeover announcement webpage&lt;/a&gt; offers very useful information on the change, and is central to this answer...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;hr&gt;&#xA;&lt;strong&gt;Correction:&lt;/strong&gt;&lt;br&gt;&#xA;There were actually 4 categories prior to the change.  The SPC used the &quot;See Text&quot; area for what is now designated as a &quot;Marginal Risk&quot;.  These did not have colors or outlines, but instead just the words &quot;See Text&quot; on the map.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that the &quot;See Text&quot; area actually did have a &quot;hidden&quot; outline, in the tornado\hail\wind risk percentage contours that went in hand with them, as in:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WXrJs.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WXrJs.png&quot; alt=&quot;See Text Example&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;hr&gt;&#xA;&lt;strong&gt;Reasoning for changes:&lt;/strong&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the shift from &quot;See Text&quot; to &quot;Marginal&quot;, SPC indicated that the trouble was the lack of a precise areal outline.  There were also concerns that the &quot;See Text&quot; area could be overlooked or confusing to the public.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the implementation of the &quot;Enhanced&quot; designation, SPC asserts that the &quot;Slight Risk&quot; covered too large a range of potential weather.  It definitely is true that &quot;Slight&quot; was by far the most used forecast.  I chose a random month prior to the changeover - July 2014... there were 23 days topping at slight risk, 3 days of moderate risks, and 5 see text days.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There were also slight realignment by weather type, and downward shifts in a couple spots.  The overall changes are summarized in this table of risk criteria:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tOWTb.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tOWTb.png&quot; alt=&quot;SPC Risk To Probabilities&quot;&gt;&lt;/a&gt;&#xA;&lt;sub&gt;&lt;sup&gt;Old data taken from &lt;a href=&quot;https://web.archive.org/web/20141007043447/http://www.spc.noaa.gov:80/misc/SPC_Prob_Conv_Otlk_Change_20060214.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;archive.org&lt;/a&gt;&lt;/sup&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;hr&gt;&#xA;&lt;strong&gt;Other Countries:&lt;/strong&gt;&lt;br&gt;&#xA;It's important to note that the US is on the forefront of focus on severe weather and especially tornado forecasting.  Many parts of the world have minimal forecasts.  One key cause of this is that the US averages over 1,000 tornadoes per year, while Canada only about 100, all of Europe about 300, and most of the rest of the world even less (see &lt;a href=&quot;https://en.wikipedia.org/wiki/Tornado_climatology&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; or &lt;a href=&quot;http://www.ustornadoes.com/2013/07/25/from-domestic-to-international-tornadoes-around-the-world/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; from ustornadoes.com).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.metoffice.gov.uk/guide/weather/warnings&quot; rel=&quot;nofollow noreferrer&quot;&gt;The UK looks like&lt;/a&gt; it uses a three color scale of yellow, amber (orange), and red for notices on all weather hazards, which is a combination of how likely the event is with impact table levels of very low, low, medium, and high for how destructive it will be.  It appears that they only issue warnings for thunderstorms, hail, and wind, not for tornadoes directly.  A more straightforward scale... though some concern that the words very low and low suggest a lack of danger... I believe the US avoids these terms for this reason, and instead strays into the words you find more confusing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.canada.ca/en/environment-climate-change/services/types-weather-forecasts-use/public/criteria-alerts.html#tornado&quot; rel=&quot;nofollow noreferrer&quot;&gt;Canada appears&lt;/a&gt; to only have watches and warnings similar to the basic US versions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.weathersa.co.za/warnings&quot; rel=&quot;nofollow noreferrer&quot;&gt;South Africa seems&lt;/a&gt; to have a yellow, orange, red scale which is a mix time and intensity.  Yellow can be either up to 5 days in advance, or a lesser weather event in the short term.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A quick look around the met office pages for &lt;a href=&quot;http://www.bom.gov.au/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Australia&lt;/a&gt;, &lt;a href=&quot;http://www.meteofrance.com/accueil&quot; rel=&quot;nofollow noreferrer&quot;&gt;France&lt;/a&gt;, &lt;a href=&quot;http://www.smn.gov.ar/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Argentina&lt;/a&gt;, &lt;a href=&quot;http://worldweather.wmo.int/en/country.html?countryCode=176&quot; rel=&quot;nofollow noreferrer&quot;&gt;Italy&lt;/a&gt;, and &lt;a href=&quot;http://www.bmd.gov.bd/?/home#Khulna&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bangladesh&lt;/a&gt; show no evidence of clearly defined outlook scales beyond equivalents of watches/warnings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My familiarity with such sites is incomplete, but the fact that &lt;a href=&quot;https://www.gizmodo.com.au/2015/11/bureau-of-meteorology-issues-actual-tornado-warning-for-melbourne/&quot; rel=&quot;nofollow noreferrer&quot;&gt;tornado warnings in Australia seem to be a rather notable curiosity&lt;/a&gt;, and that the Bangladesh main met office page has a counter suggesting only 160,000 visits highlights that the US may well be in a very unique situation in terms of regular supercellular weather and heightened attention to its threats.  And so detailed scales for such weather may be without comparison.  However, though many other nations certainly have threats to cause great consideration, be it blizzards, tropical cyclones, or sand storms... there doesn't appear to be widespread usage of scales with as many levels as the SPC convective outlook.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;hr&gt;&#xA;&lt;strong&gt;Validity:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I believe you're right to question it...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A small study in the dissertation entitled &lt;a href=&quot;https://www.google.com/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=4&amp;amp;ved=0ahUKEwj5nsWi44HYAhWH2SYKHW-gADAQFghDMAM&amp;amp;url=https%3A%2F%2Fd.lib.msu.edu%2Fetd%2F3197%2Fdatastream%2FOBJ%2Fdownload%2FCommunicating_natural_hazard_risk___warnings__decisions_and_precautionary_behavior.pdf&amp;amp;usg=AOvVaw3Zet0ZVXV5WGquye9sZokM&quot; rel=&quot;nofollow noreferrer&quot;&gt;Communicating Natural Hazard Risk: Warnings, Decisions, and Precautionary Behavior&lt;/a&gt; by Robert Drost (which likely overlaps the subsequent journal article &lt;a href=&quot;http://journals.ametsoc.org/doi/full/10.1175/WCAS-D-15-0035.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Severe Weather Warning Communication: Factors Impacting Audience Attention and Retention of Information during Tornado Warnings&lt;/a&gt;, which is still unavailable except to subscribers, so I have not read)... found that &lt;strong&gt;37% of the participants were unable to distinguish between a watch and a warning&lt;/strong&gt;.  (Given that the study is of young college students, this probably greatly underestimates overall misunderstanding in the public... though the use of such a small selective sample means the value could be quite inaccurate in any direction).  If we're struggling with fundamental terminology important to direct life-or-death decisions, changes like these do seem hindering to the public.  I spend a lot time on Facebook tv station livestreams during severe weather, meeting and talking through questions with the public... and in my experience you're right that more people are struggling with the new categories.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is one perspective that may help offer some understanding and even support the SPC changes; there has always been a loose pattern suggesting that the SPC and other NWS specialized offices aim slightly more at meteorologists and emergency managers than the general public.  This is reflected in the extensive usage of complex terminology throughout the site, the conspicuous citation of journal articles, the presentation of statistics and percentages that really wouldn't have much grounding to the general public, and the rather unadorned pages and overloaded navigation menus that all make it very hard for people unfamiliar with the sites to know where to find what they need.  The new categorization may be quite confusing to the general public, but for an active meteorologist, they were quickly adapted to.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the SPC and its brethren at the same time puts a great deal of emphasis on mediums like Twitter and Facebook and does television interviews in key weather events.  So it could reasonably argue that in reality, they are also trying to be public-facing entities.  And in the end they wind up having multiple competing personalities/goals (perhaps true of all of the NWS?)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the end, the goal of course goes back to prewarning the public.  The SPC may wish the broadcast media can consolidate the messages they put out, perhaps down to just a simpler &quot;there is a chance of tornadoes today&quot;.  But the reality is that people clamor for exact values and maps, even at times when they aren't that useful.  And so it typically ends up that the outlook map does make it on to the public (or, more troubling yet, presenters create their own competing scales).  And so we wind up back at the issue that the scale probably confuses the public.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We all know that at some point, information overload is a problem.  And that too many terms will confuse people.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So indeed it may well be after all that the relatively minor severe weather events don't need an outline and term to show it as less than &quot;Slight&quot;, but rather just a little hint on the image like &quot;See Text&quot; offered.&lt;br&gt;&#xA;And whether or not &quot;Enhanced&quot; helps better warn than confuse people is a very legitimate question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the end, the SPC page did note that &quot;the NWS has a strong commitment to engaging the social sciences in evolving our services, and this community has helped inform our decision making for this change.&quot;  That's where we must look to.  No studies were published on this change that I know of.  But we have to hope they'll continue to look into it.  Social science is definitely still rather nascent and under-explored in meteorology.  Here's to hoping that greater attention and resources can be dedicated to weighing terms and categories like these.  You've raised a good, helpful point... and one that hopefully filters back to the people making these decisions, encouraging some more firm answers and data.  It's something we definitely need to be thinking about more!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-12-14T06:23:59.637" LastActivityDate="2017-12-14T06:23:59.637" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12892" PostTypeId="2" ParentId="10154" CreationDate="2017-12-13T14:59:43.170" Score="0" Body="&lt;p&gt;Aha, it's all about what search terms you use.  I stumbled across a series of papers that gives a great range of calculations from J. Brotzge and Erickson.  The key one for this topic appears to be Brotzge, Erickson, and Brooks: &lt;a href=&quot;http://journals.ametsoc.org/doi/full/10.1175/WAF-D-10-05004.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;A 5-yr Climatology of Tornado False Alarms&lt;/a&gt;.  The key figure is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/g6Rke.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/g6Rke.jpg&quot; alt=&quot;Tornado Forecasting By Distance&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The take-homes are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;As distance increases, tornadoes are missed more&lt;/strong&gt; by advanced warning.  This is shown by the black circles [probability of detection] trending down slowly on the left graph.  The drop-off is certainly very gradual, going from near 80% of tornadoes with advanced warning in sites just outside the &lt;a href=&quot;http://www.radartutorial.eu/18.explanations/ex47.en.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;cone of silence&lt;/a&gt;, to nearer 60% out beyond 100 miles (160 km) from the radar.  But this does mean that near the radar about 1 in 5 tornadoes is missed, while beyond 100 miles, it's nearer 2 in 5 tornadoes missed.&lt;/li&gt;&#xA;&lt;li&gt;Oddly, it appears that &lt;strong&gt;warnings actually verify BETTER out beyond 100 miles&lt;/strong&gt; (160 km).  This is shown by the open circles [success ratio] increasing in the left graph, and is further confirmed by the same increase when breaking it down into group bins in the right graph.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The authors give a few theories to attempt to explain the increase in success beyond 100 miles (160 km).  They hint that it may be due in part to the fact that forecasters wait to issue warnings until receiving confirmation because the radar data is less helpful in properly identifying developing rotation.  However, this seems it should likely be matched by a giant dropoff in POD if it were a large contributing factor.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;They also suggest the increased success in long ranges verification may be simply due to the fact less tornadoes are reported at large distances.  Reasons given include: people won't know where to look for weak tornado damage due to the poor radar quality; the disposition for these areas to typically have fewer residents... fewer residents mean less people to potentially see the tornadoes, and also less houses and such to be damaged [they did try to eliminate this factor as an option, but did not seem to do so adequately to me];  and perhaps the cause of less reports could in part be due to less NWS surveys because of the large distances to travel.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regardless, the key is the slow dropoff in tornadoes getting properly warned.  If the strange decrease in unnecessary warnings is legitimate, that might almost counteract any benefit to adding radars.  But it's very unlikely the lack of data somehow makes forecasters much better.  If that proved true, it'd be remarkable, and lead to heavy investigation into what we could do to duplicate the effects everywhere!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course none of this considers places at even longer-range distances (particularly those beyond the 143 mile &lt;a href=&quot;https://www.weather.gov/iwx/wsr_88d&quot; rel=&quot;nofollow noreferrer&quot;&gt;short-range limit&lt;/a&gt;), which is where attention is often first placed when fomenting &lt;a href=&quot;https://www.washingtonpost.com/news/capital-weather-gang/wp/2015/07/22/u-s-radars-have-come-a-long-way-but-gaps-in-coverage-remain-big-a-risk/?utm_term=.0bf206959b10&quot; rel=&quot;nofollow noreferrer&quot;&gt;support for additional radars&lt;/a&gt;.  And the study could probably also do with some additional years of data to further eliminate any potential biases due to inter-annual weather patterns.  But it's definitely a very fair start towards addressing the cost-benefit of radar installation. &lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2017-12-13T23:11:10.810" LastActivityDate="2017-12-13T23:11:10.810" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12897" PostTypeId="1" AcceptedAnswerId="12900" CreationDate="2017-12-14T05:59:28.090" Score="5" ViewCount="848" Body="&lt;p&gt;Some studies about Earth's fosilized plants/animals mention a &quot;Oligo-Miocene radiation&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Examples:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Our study therefore strengthens previous suggestions that the absence&#xA;  of very large penguins today is likely due to the Oligo-Miocene&#xA;  radiation of marine mammals.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;from Mayr et al (2017), doi: &lt;a href=&quot;http://dx.doi.org/10.1038/s41467-017-01959-6&quot; rel=&quot;noreferrer&quot;&gt;10.1038/s41467-017-01959-6&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Molecular phylogeny and dating reveals an Oligo-Miocene radiation of&#xA;  dry-adapted shrubs (former Tremandraceae) from rainforest tree&#xA;  progenitors (Elaeocarpaceae) in Australia&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;from Crayn et al. (2006), doi: &lt;a href=&quot;http://dx.doi.org/10.3732/ajb.93.9.1328&quot; rel=&quot;noreferrer&quot;&gt;10.3732/ajb.93.9.1328&lt;/a&gt;, see also &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pubmed/21642198&quot; rel=&quot;noreferrer&quot;&gt;www.ncbi.nlm.nih.gov/pubmed/21642198&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, what is this &quot;Oligo-Miocene radiation&quot; ?&lt;/p&gt;&#xA;" OwnerUserId="11793" LastEditorUserId="2570" LastEditDate="2017-12-14T08:43:09.630" LastActivityDate="2017-12-14T08:43:55.560" Title="What is Oligo-Miocene radiation?" Tags="|terminology|paleontology|fossils|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12898" PostTypeId="2" ParentId="12801" CreationDate="2017-12-14T06:37:08.053" Score="2" Body="&lt;p&gt;New water introduction scenarios, other than through the &lt;a href=&quot;https://www.thenakedscientists.com/articles/questions/any-new-water-being-formed-our-planet&quot; rel=&quot;nofollow noreferrer&quot;&gt;biological processes&lt;/a&gt; mentioned in the question:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;When ice(H&lt;sub&gt;2&lt;/sub&gt;O) meteorites/asteroids enter Earth's atmosphere they melt into water&lt;/li&gt;&#xA;&lt;li&gt;When Meteorite containing Oxygen compounds reacts with hydrogen in the upper atmosphere, and creates water &lt;/li&gt;&#xA;&lt;li&gt;If Meteorite containing Hydrogen compounds reacts with oxygen in the lower atmosphere, and creates water [unlikely]&lt;/li&gt;&#xA;&lt;li&gt;If Earth passes through a comet's trail or nebula containing Hydrogen or Oxygen, which reacts with Earth's Hydrogen/Oxygen to create water [unlikely]&lt;/li&gt;&#xA;&lt;li&gt;If Earth passes through a comet's trail or nebula containing ice(H&lt;sub&gt;2&lt;/sub&gt;O) [unlikely]&lt;/li&gt;&#xA;&lt;li&gt;If the Hydrogen from the upper atmosphere somehow meets Oxygen in the lower atmosphere [very unlikely]&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="11793" LastEditorUserId="11793" LastEditDate="2017-12-14T06:53:21.840" LastActivityDate="2017-12-14T06:53:21.840" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12899" PostTypeId="2" ParentId="12897" CreationDate="2017-12-14T08:42:06.563" Score="3" Body="&lt;p&gt;Radiation here has nothing to do with radioactivity. In this context it is refers to a diversification of marine mammals. It is a common term used in evolutionary biology.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Radiation: 'divergence out from a central point, in particular evolution from an ancestral animal or plant group into a variety of new forms.'&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2017-12-14T08:42:06.563" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12900" PostTypeId="2" ParentId="12897" CreationDate="2017-12-14T08:43:55.560" Score="8" Body="&lt;p&gt;&lt;strong&gt;The ‘Oligo-Miocene’ part&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Oligocene&quot; rel=&quot;noreferrer&quot;&gt;Oligocene&lt;/a&gt; and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Miocene&quot; rel=&quot;noreferrer&quot;&gt;Miocene&lt;/a&gt; are epochs of geological time. The Oligocene lasted from ~33.9 million years ago to ~23 million years ago; the Miocene followed immediately after the Oligocene, and lasted until ~5 million years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Oligo-Miocene&lt;/em&gt; refers to events that happened around the boundary between the two epochs at ~23 million years, or that happened throughout the Oligocene and Miocene epochs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The ‘radiation’ part&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;‘Radiation’ here is evolutionary radiation, a biological term usually referring to an increase in the number of species or in the differences between them. The Palaeontology Online glossary &lt;a href=&quot;https://www.palaeontologyonline.com/glossary/e/evolutionary-radiation/&quot; rel=&quot;noreferrer&quot;&gt;defines&lt;/a&gt; ‘evolutionary radiation’ as follows.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;An evolutionary radiation is an increase in either taxonomic diversity (i.e. the number of species) or morphological disparity (how they differ in anatomy). This can result  from an adaptive change or the opening of ecospace.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The combination&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Putting the two parts back into the contexts where you found them: the first article mentions an increase in the diversity or marine mammals, and the second in the diversity of dry-adapted shrubs. Both these increases occurred between the start of the Oligocene and the end of the Miocene.&lt;/p&gt;&#xA;" OwnerUserId="94" LastActivityDate="2017-12-14T08:43:55.560" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12901" PostTypeId="2" ParentId="10627" CreationDate="2017-12-14T11:05:13.723" Score="1" Body="&lt;p&gt;Smog is Air pollution + Water Vapour(Cloud)&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;NO&lt;sub&gt;2&lt;/sub&gt; (Nitrogen Dioxide) : deep red-orange&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;H&lt;sub&gt;2&lt;/sub&gt;O (Water Vapour) : White&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Nitrogen oxide, Sulfur oxide, Sulfur dioxide are said to be transparent gases.&lt;/p&gt;&#xA;" OwnerUserId="11793" LastActivityDate="2017-12-14T11:05:13.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12902" PostTypeId="1" CreationDate="2017-12-14T11:50:39.510" Score="9" ViewCount="3127" Body="&lt;ul&gt;&#xA;&lt;li&gt;Nitrous oxide ($N_2O$) - primary greenhouse gas&lt;/li&gt;&#xA;&lt;li&gt;Carbon dioxide ($CO_2$) - primary greenhouse gas&lt;/li&gt;&#xA;&lt;li&gt;Methane ($CH_4$) - primary greenhouse gas, explosive&lt;/li&gt;&#xA;&lt;li&gt;Nitrogen monoxide ($NO$) - secondary greenhouse gas, toxic&lt;/li&gt;&#xA;&lt;li&gt;Nitrogen dioxide ($NO_2$) - secondary greenhouse gas, toxic&lt;/li&gt;&#xA;&lt;li&gt;Sulfur dioxide ($SO_2$) - secondary greenhouse gas, toxic&lt;/li&gt;&#xA;&lt;li&gt;Carbon monoxide ($CO$) - secondary greenhouse gas, toxic&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So, why is Carbon Dioxide pollution  given more importance in &quot;pollution measurement&quot;(Carbon-Footprints), when Sulfur Dioxide and Nitrogen Dioxide are much more dangerous to Land dwellers, including Humans ? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At this rate, the Oceans will &lt;a href=&quot;https://www.scientificamerican.com/article/ocean-dead-zones/&quot; rel=&quot;noreferrer&quot;&gt;die from Nitrogen pollution&lt;/a&gt; or &lt;a href=&quot;https://thenewinquiry.com/myth-of-the-garbage-patch/&quot; rel=&quot;noreferrer&quot;&gt;acidify from Plastic pollution&lt;/a&gt;; before the ocean level can even threaten us. So, why are we focusing on Carbon dioxide at the cost of the toxic compounds ? &lt;/p&gt;&#xA;" OwnerUserId="11793" LastEditorUserId="6465" LastEditDate="2017-12-14T15:37:35.583" LastActivityDate="2017-12-14T15:37:35.583" Title="Why is carbon pollution given more importance than Sulfur pollution or Nitrogen pollution?" Tags="|climate-change|oceanography|pollution|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="12903" PostTypeId="2" ParentId="12902" CreationDate="2017-12-14T12:47:18.640" Score="11" Body="&lt;h1&gt;greenhouse gases other than CO&lt;sub&gt;2&lt;/sub&gt;&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The gases N&lt;sub&gt;2&lt;/sub&gt;O and CH&lt;sub&gt;4&lt;/sub&gt; are relevant greenhouse gases besides CO&lt;sub&gt;2&lt;/sub&gt;. They even have a stronger warming impact per molecule. A brief summary for N&lt;sub&gt;2&lt;/sub&gt;O is provided in &lt;a href=&quot;https://en.wikipedia.org/wiki/Nitrous_oxide#Greenhouse_effect&quot; rel=&quot;noreferrer&quot;&gt;its Wikipedia article&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Edited later on (thanks to Communisty for the comment):&lt;/em&gt; The global warming impact of these greenhouse gases other than CO2 is measured/presented in CO2-equivalents: i.e. the warming potential of N2O equals 298 CO2-equivalents, which means that one N2O molecule is 298 times &lt;em&gt;worse&lt;/em&gt; than a CO2 with respect to its warming potential. Therefore, CO2 is more visible in the media.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Why focus more on CO&lt;sub&gt;2&lt;/sub&gt;?&lt;/h1&gt;&#xA;&#xA;&lt;h2&gt;contribution to global warming&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Although N&lt;sub&gt;2&lt;/sub&gt;O and CH&lt;sub&gt;4&lt;/sub&gt; have a stronger greenhouse impact than CO&lt;sub&gt;2&lt;/sub&gt; per molecule, the concentrations of them are considerably lower. Therefore, in sum (heat trapping potential x number) CO&lt;sub&gt;2&lt;/sub&gt; has a stronger impact on climate change. The figure below visualizes it nicely (please find the reference below):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WxQyT.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WxQyT.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_TS_FINAL.pdf&quot; rel=&quot;noreferrer&quot;&gt;Figure TS.6&lt;/a&gt; on page 53 of the 5th IPCC Assessment on the Physical Science Basis (&lt;a href=&quot;https://www.ipcc.ch/report/ar5/wg1/&quot; rel=&quot;noreferrer&quot;&gt;www.ipcc.ch/report/ar5/wg1/&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;practical aspects&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;There are also practical aspects why a focus is put on CO&lt;sub&gt;2&lt;/sub&gt;: many CO&lt;sub&gt;2&lt;/sub&gt; emission sources are know and clearly to identify (combustion processes). Moreover, many of the CO&lt;sub&gt;2&lt;/sub&gt; sources are point sources. Some of them are many and small (cars) but nonetheless: we know them and know to locate them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In contrast, N2O and CH4 emissions sources are often diffusive sources (or &lt;em&gt;area sources&lt;/em&gt;) such as natural and agricultural soils and cattle (and other) life stock. Here you find a text and a nice figure on this topic: &lt;a href=&quot;http://www.soest.hawaii.edu/mguidry/Unnamed_Site_2/Chapter%202/Chapter2C3.html&quot; rel=&quot;noreferrer&quot;&gt;www.soest.hawaii.edu/mguidry/Unnamed_Site_2/Chapter%202/Chapter2C3.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, it is easier to reduce CO&lt;sub&gt;2&lt;/sub&gt; emission by specific measures: &lt;strong&gt;don't combust so much fuel/combustion-material.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;greenhouse gases vs. air pollution&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;As stated above, CO2 (in sum) has a higher global warming impact (in the moment). And large parts of its emissions are easier to manage. Therefore, the focus is on CO2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Moreover, greenhouse gas emissions have a global impact: the greenhouse gases alter the global climate. In contrast, air pollutants have a local or regional impact. Also their life time or/and residence time in the lower troposphere is shorter than the residence time of greenhouse gases in the atmosphere. Therefore, the temporal and spatial extend of greenhouse gases is larger/longer than that of air pollutants. Thus, one focuses more on the longer lasting global problem: greenhouse gases.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;regional vs. global&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Because greenhouse gas emissions cause global problems they are tackled on a global level -- IPCC, United Nations Climate Change Conferences, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although air pollution is also a topic dealt with on global or continental level (e.g. &lt;a href=&quot;http://www.htap.org/&quot; rel=&quot;noreferrer&quot;&gt;hemispheric transport of air pollutants (HTAP)&lt;/a&gt;, &lt;a href=&quot;http://www.emep.int/&quot; rel=&quot;noreferrer&quot;&gt;European Monitoring and Evaluation Programme (EMEP)&lt;/a&gt;), it is mainly a regional or local problem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Europe many municipalities have recognized the problem of air pollution in cities and try to deal with it (actually, they are forced by the EU). Also in Chinese cities municipalities start working on this topic.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastEditorUserId="5594" LastEditDate="2017-12-14T15:18:06.333" LastActivityDate="2017-12-14T15:18:06.333" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12904" PostTypeId="1" AcceptedAnswerId="12925" CreationDate="2017-12-14T12:10:44.683" Score="4" ViewCount="114" Body="&lt;p&gt;I got datasets about Tsunami events.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to International Tsunami Information Center and Indian Ocean UNESCO Tsunami center, for an earthquake to cause Tsunami it should have a large magnitude (&gt; 6.5) and shallow focal depth ( &amp;lt; 100 km ).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But there are entries in NOAA tsunami dataset with focal depth of 260 km and a magnitude of 6.8 occurred at sea with the epicenter located at 21.1 km from the nearest coast. There are also entries with magnitude range of 4-5 causing tsunamis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there some other characteristics of earthquake that may cause tsunami?&lt;/p&gt;&#xA;" OwnerUserId="11797" OwnerDisplayName="Gautham" LastEditorUserId="5594" LastEditDate="2017-12-14T15:23:36.103" LastActivityDate="2018-01-17T02:50:47.090" Title="Tsunami Characteristics" Tags="|tsunami|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12907" PostTypeId="1" AcceptedAnswerId="12910" CreationDate="2017-12-14T15:43:18.310" Score="2" ViewCount="677" Body="&lt;p&gt;Does a push broom scanner scan a path perpendicular to the direction of satellite travel? I am confused because its detectors are arranged across track even though it scans along track.&lt;/p&gt;&#xA;" OwnerUserId="11799" LastEditorUserId="5594" LastEditDate="2017-12-14T16:02:26.100" LastActivityDate="2017-12-14T17:46:50.630" Title="Understanding pushbroom sensors" Tags="|remote-sensing|earth-observation|electromagnetism|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12909" PostTypeId="1" CreationDate="2017-12-14T17:24:49.497" Score="2" ViewCount="73" Body="&lt;p&gt;There are three geothermal systems that are commonly used: dry steam, flash steam, and binary cycle&lt;a href=&quot;https://www.eia.gov/energyexplained/index.cfm?page=geothermal_power_plants&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;sup&gt;[1]&lt;/sup&gt;&lt;/a&gt;. What are the efficiencies of the plants from best to least efficient? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I did a moderate amount of research on all three systems, but the only thing that I found on Google is the efficiency of geothermal as a whole.  I could not find anything regarding the the efficiency of each individual one. &lt;/p&gt;&#xA;" OwnerUserId="11802" LastEditorUserId="6298" LastEditDate="2017-12-15T08:01:50.620" LastActivityDate="2017-12-15T08:01:50.620" Title="Which geothermal power plant type is most effecient?" Tags="|geology|temperature|geothermal-heat|" AnswerCount="0" CommentCount="5" ClosedDate="2017-12-15T08:47:47.193" ContentLicense="CC BY-SA 3.0" />
  <row Id="12910" PostTypeId="2" ParentId="12907" CreationDate="2017-12-14T17:46:50.630" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Does the image of the pushbroom scans a path perpendicular to the direction of satellite travel?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not really. There is no &quot;scanning&quot; in a push broom sensor. A push broom sensor does not have any moving parts; compare with the related whisk broom sensor which does indeed scan a path perpendicular to the satellite's motion. The difference between the two is that a push broom sensor has multiple identical sensors arranged in a line (orthogonal to the nominal direction of travel) while a whisk broom sensor has but one sensor. The line of sensors in a push broom sensor eliminates the need for scanning.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both types of sensors form an image by forming image lines and then pasting those image lines, one after another, into an image buffer. A push broom sensor forms an image line by exposing all of the sensors to light simultaneously. A whisk broom sensor forms an image line by taking a series of snapshots, rotating the sensor a bit between each snapshot. With both kinds of sensors, the satellite's motion between capturing individual lines is what enables an image to be formed.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2017-12-14T17:46:50.630" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12911" PostTypeId="1" CreationDate="2017-12-14T18:39:40.210" Score="3" ViewCount="70" Body="&lt;p&gt;The water held underground in a geothermal system is under high temperature and pressure. Are pumps used to raise the very hot underground water to the surface or does the water rise under its own pressure? One source says that the water is pumped up&lt;a href=&quot;https://energy.gov/eere/geothermal/electricity-generation&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;sup&gt;[1]&lt;/sup&gt;&lt;/a&gt; while another says that it rises on its own&lt;a href=&quot;https://www.youtube.com/watch?v=kjpp2MQffnw&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;sup&gt;[2]&lt;/sup&gt;&lt;/a&gt;. I am not sure if I just misunderstand the wording. Does anyone know which is correct?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1]: &lt;a href=&quot;https://energy.gov/eere/geothermal/electricity-generation&quot; rel=&quot;nofollow noreferrer&quot;&gt;energy.gov/eere/geothermal/electricity-generation&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[2]: &lt;a href=&quot;https://www.youtube.com/watch?v=kjpp2MQffnw&quot; rel=&quot;nofollow noreferrer&quot;&gt;www.youtube.com/watch?v=kjpp2MQffnw&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11802" LastEditorUserId="5594" LastEditDate="2017-12-14T21:52:23.240" LastActivityDate="2018-03-14T23:14:25.723" Title="Are pumps used in geothermal systems?" Tags="|geology|temperature|geothermal-heat|earth-system|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12912" PostTypeId="2" ParentId="12911" CreationDate="2017-12-14T20:02:47.127" Score="1" Body="&lt;p&gt;Pumped systems are much more common. However, there are some artesian type hot springs where the water flows spontaneously and is not replenished in the immediate area. &lt;/p&gt;&#xA;" OwnerUserId="8409" LastEditorUserId="5594" LastEditDate="2017-12-14T21:45:54.433" LastActivityDate="2017-12-14T21:45:54.433" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12913" PostTypeId="1" CreationDate="2017-12-14T22:15:04.490" Score="2" ViewCount="13771" Body="&lt;p&gt;I was trying to figure out what areas in North America would be most likely to have earthquakes, but I couldn't come across a good map for this. It's easy to find the areas with the highest incidence of hurricanes and tornadoes, and I know California has a high rate of earthquakes. What fault lines are there in North America (besides the obvious San Andreas fault)? Are there any maps that clearly show this?&lt;/p&gt;&#xA;" OwnerUserId="11805" LastEditorUserId="20" LastEditDate="2017-12-20T21:33:28.220" LastActivityDate="2017-12-22T10:09:45.370" Title="Fault Lines in North America" Tags="|geography|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="12915" PostTypeId="1" CreationDate="2017-12-15T11:24:08.653" Score="2" ViewCount="42" Body="&lt;p&gt;I would like to calculate the prior probability of active precipitation currently taking place at any random moment during a year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The area I’m looking at (London, UK) has averages of 601.7mm of rain and 109.6 precipitation days per year (according to &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Climate_of_London&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.m.wikipedia.org/wiki/Climate_of_London&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I haven’t been able to find any historical data for “time spent raining”, nor for average the distribution of rain intensity (which would also help me estimate this), for any area. Is this data publicly available anywhere?&lt;/p&gt;&#xA;" OwnerUserId="11809" LastActivityDate="2018-01-15T12:21:03.870" Title="Calculating mean time spent precipitating for a specified period/area?" Tags="|rainfall|statistics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12916" PostTypeId="1" CreationDate="2017-12-15T19:03:15.787" Score="1" ViewCount="182" Body="&lt;p&gt;I've seen some problem sets given without answers / solutions regarding how to calculate the composition of the mantle given solar composition (and assuming the same would apply to the Earth). For example, the MIT open courseware MOOC has this type of problem in example sheet 1: &lt;a href=&quot;https://ocw.mit.edu/courses/earth-atmospheric-and-planetary-sciences/12-001-introduction-to-geology-fall-2013/labs-and-exercises/&quot; rel=&quot;nofollow noreferrer&quot;&gt;MIT geology online course&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given wt% of various substances and factors like how much of the total mass is made up of the core, how do you go about calculating the composition of the mantle. At first pass it seems straightforward but when I actually try to write down some equations and ratios I don't know where to go. &lt;/p&gt;&#xA;" OwnerUserId="11813" LastActivityDate="2017-12-15T19:03:15.787" Title="Mass balance for calculating mantle composition" Tags="|geology|geochemistry|mantle|solar-terrestrial-physics|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12918" PostTypeId="2" ParentId="12877" CreationDate="2017-12-15T23:23:41.787" Score="2" Body="&lt;p&gt;As you probably know, the melting temperature in the mantle is a function of H&lt;sub&gt;2&lt;/sub&gt;O contents. The more H&lt;sub&gt;2&lt;/sub&gt;O you have, the lower the melting point of the rocks (i.e. dry vs wet solidus in the sketch). A less known phenomenon is the decrease of melting point with the addition of CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The CO&lt;sub&gt;2&lt;/sub&gt; melting curve has a weird shape. At low pressures nothing much happens, but there's a certain pressure where all of the sudden CO&lt;sub&gt;2&lt;/sub&gt; is soluble in the melt and it greatly depresses the melting point. This kink is known as the &quot;carbonate ledge&quot;. The exact depth of the ledge depends on the composition of the rocks and the experimentalist that performed the experiments, but it's somewhere around two to three GPa, corresponding to about 65 to 100 km deep. Low degree melts above the solidus (the yellow area) are proper carbonatites, and higher degree melts are all kinds of carbonated alkaline melts, with more CO&lt;sub&gt;2&lt;/sub&gt; dissolved in them at higher pressures. True hybrid carbonate and silicate melts are only possible at pressures of let's say 4-5 GPa and higher. Below that an immiscibiliy gap exists (also dependent on the alkali contents of the melts - more alkalis = more miscibility).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qS5O6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qS5O6.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;redox melting&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, for this to happen you obviously need to have CO&lt;sub&gt;2&lt;/sub&gt; in the mantle. But CO&lt;sub&gt;2&lt;/sub&gt; is the oxidised form of carbon. In general, the deeper you go in the mantle the more reduced the conditions are. The roots of cratonic lithospheric mantle are very reduced and any carbon in there occurs in the form of reduced carbon: diamonds. Diamonds are no good in facilitating carbonated melting of mantle rocks. However, if a process of metasomatism of fluid flow causes oxidation of the diamonds, they transform to CO&lt;sub&gt;2&lt;/sub&gt; thus enabling the formation of carbonated mantle melts.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-12-15T23:23:41.787" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12919" PostTypeId="1" CreationDate="2017-12-16T05:02:58.177" Score="1" ViewCount="103" Body="&lt;p&gt;I was wondering if aerobic decomposition of organic rich soils, also rich in calcium and sulfur, can result in the precipitation of gypsum. My thinking is the decomposition would release the organically bound Ca to soluble form, and the mineralization of organic sulfur would release in sulfate. Then over time as the soil decomposes more higher concentrations of both calcium and sulfur would precipitate out gypsum. Am I correct in saying this? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="11554" LastActivityDate="2017-12-16T05:02:58.177" Title="Formation of minerals from decomposition of soil" Tags="|mineralogy|soil|biogeochemistry|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12921" PostTypeId="2" ParentId="12915" CreationDate="2017-12-16T11:23:08.063" Score="1" Body="&lt;p&gt;Check with the &lt;a href=&quot;https://www.metoffice.gov.uk/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Met Office&lt;/a&gt; to see what data is available.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My experience, from elsewhere, is that weather data: temperature, pressure and precipitation are recorded at important weather stations at half hourly intervals, with the data being in the format shown below&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ar5pt.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ar5pt.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With data in format it is easy to determine the  &quot;time spent raining&quot; to a precision of half an hour.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-12-16T11:23:08.063" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12922" PostTypeId="2" ParentId="12696" CreationDate="2017-12-17T11:33:30.003" Score="2" Body="&lt;p&gt;As &lt;a href=&quot;https://earthscience.stackexchange.com/a/12698/6298&quot;&gt;Fred said&lt;/a&gt;, it's just an unfortunate word choice that makes you think the professor is suggesting air flows towards the high.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Indeed, a surface high pressure south of Sydney would be the circumstance to have the air circulate around it in such a way as to &quot;draw&quot; air onshore from off the shore... even as it's actually really flowing somewhat away from the high.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's a long-range model forecast showing exactly this setup building after a strong low potentially passes by this week... and so Sydney may be held cooler again just in time for Boxing Day:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HJzcQ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HJzcQ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;sub&gt;&lt;sup&gt;from www.pivotalweather.com&lt;/sup&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(This is only one model's long-range forecast, and the skill in such forecasts is quite low.  I present it to show this scenario, not to make any forecast as to whether it'll actually happen next week)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see the green arrows are bringing air onshore.  &lt;a href=&quot;http://oceancurrent.imos.org.au/sst.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;This link&lt;/a&gt; suggests current ocean surface temperatures are around 23°C (73°F).  So that would likely reduce the temperature slightly (if you explore the plots at pivotalweather.com for Australia, it currently shows a forecast high closer to 23°C for the day, rather than nearer the 30s many spots in the area see tomorrow).&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;There's actually more to consider:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, the pressure gradient force causes air to be pushed from high pressure to low pressure.  However, other forces typically counteract a large part of this, such that at the surface, air flows quite tangentially (most in a circle, rather than moving inward or outward).  This is because as moves from the high to the low, the rotation of the Earth causes the winds to appear to miss its original destination (&lt;a href=&quot;https://en.wikipedia.org/wiki/Coriolis_force&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Coriolis Force&lt;/a&gt;).&#xA;Higher up in the atmosphere, this actually causes air to generally not even flow from high pressure to low pressure at all!  At surface levels, there's a fair bit of friction which slows wind down the wind some, and thereby causes the Coriolis impact to be less than it should.&lt;br&gt;&#xA;At those more significantly high levels in the atmosphere, since there's no appreciable frictional effects, the earth's rotation entirely resists the high-to-low movement over long periods of time, and you end up with a wind that instead cuts perpendicular to both, not getting nearer or further away:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3udbr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3udbr.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;sub&gt;&lt;sup&gt;from www.pivotalweather.com&lt;/sup&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(Once again, only one model's long-range calculation, and not a reliable forecast.  But... let's just say that won't bring tropical hurricane weather if it comes together!)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Look closely and compare, and you should be able to see, both in the little black line segment symbols showing wind flow, and in my arrows drawn to show a more continual path (if I managed to draw the arrows well enough!), that the wind is flowing outwards some in the Australia picture... but in the US picture (which is showing heights up closer to 5 km [3 mi] above the ground), the wind is basically perfectly balanced, neither getting near or closer... which is also matched in the the western region which winds are &quot;slaloming&quot; between a low over NW Canada and a high nearer Seattle).  [in case it causes confusion, remember highs/lows rotate the opposite direction in opposite hemispheres, so the high in Australia is clockwise, and the low in the US is clockwise]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The upper-level forces directing the wind display what is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Geostrophic_wind&quot; rel=&quot;nofollow noreferrer&quot;&gt;geostrophic wind balance&lt;/a&gt;.  The low-level winds are called &lt;a href=&quot;http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/fric.rxml&quot; rel=&quot;nofollow noreferrer&quot;&gt;ageostrophic&lt;/a&gt; because the friction leads to imbalance.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Regarding &lt;a href=&quot;https://earthscience.stackexchange.com/a/12702/6298&quot;&gt;haresfur's answer&lt;/a&gt;, while he's incorrect that the wind sneaks into the high from another cardinal direction (air basically flows outwards from surface high pressures towards the north, the south, the east, and the west all at the same time)... it is also indeed true that conservation of mass does have an additional consequence: it causes air to move vertically to counteract the air flow between the pressure systems [for near the surface, air sinks down into the high from above to replace the lost air moving outwards... and air rises up from a low to evacuate the excess incoming air].  The overall net change in air amount can cause a high pressure to build even stronger despite the fact it seems to be losing air on a weather map... and likewise cause lows to get even stronger despite large convergent flow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are complex factors [such as the fact that the volume of air changes when the temperature changes... and in the end, moisture condensation is the central driver of the growth of most pressure systems (also called latent heat release)], all that help determine this ledger balance, and whether highs and lows will continue to ramp up or die off.  But it's just worth thinking about the &lt;a href=&quot;https://rgsweather.files.wordpress.com/2014/08/2014-08-30_14-10-11.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;3-D picture sometimes&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2017-12-17T11:33:30.003" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12925" PostTypeId="2" ParentId="12904" CreationDate="2017-12-18T01:55:02.647" Score="2" Body="&lt;p&gt;The rupture velocity of earthquakes is another factor that determines the magnitude of a tsunami.  The term &lt;a href=&quot;https://en.wikipedia.org/wiki/Tsunami_earthquake&quot; rel=&quot;nofollow noreferrer&quot;&gt;tsunami earthquakes&lt;/a&gt; was coined by Hiroo Kanamori in 1972 to describe when an earthquake having a slower rupture velocity (~1km/sec), compared to a more normal velocity (2.5-3.5 km/sec) of a typical earthquake, causes a tsunami greater in magnitude than expected. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.eri.u-tokyo.ac.jp/people/seno/Papers/2001GL013149.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;This paper&lt;/a&gt; investigates the effect of a horizontal movement of sediments due to an 1896 earthquake that may have created a tsunami earthquake.  &lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2017-12-18T01:55:02.647" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12926" PostTypeId="1" CreationDate="2017-12-18T02:00:20.790" Score="8" ViewCount="173" Body="&lt;p&gt;I have learned that:     &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;coral reefs are made up mostly of calcium carbonate &lt;/li&gt;&#xA;&lt;li&gt;coral reefs are mainly distributed in the tropical zone&lt;/li&gt;&#xA;&lt;li&gt;The calcium carbonate will be decomposed in the reaction as follows:&lt;br&gt;&#xA;$$CaCO_3 + H_2CO_3 -&amp;gt; Ca^{2+} + 2HCO_3^-$$ &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Thus this reaction will be promoted in the environment with low pH. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ocean in the tropic zone should have lower acidity (higher pH) for the coral reef to exist.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But in my opinion, the pH in the ocean is determined by the dissolution of CO2, and this process might be promoted in higher temperature?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How to explain this issue?&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="111" LastEditDate="2017-12-18T14:27:05.937" LastActivityDate="2019-04-16T18:02:45.500" Title="What controls the acidity of the ocean?" Tags="|geology|ocean|climate|geochemistry|carbon|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12927" PostTypeId="1" CreationDate="2017-12-18T04:28:48.797" Score="7" ViewCount="523" Body="&lt;p&gt;What factors influence cloud height and type?  For example, why do altocumulus clouds fail to form at 6400m in high latitude locations, but will form at this height at a lower latitude? Is it simply an issue of temperature?&lt;/p&gt;&#xA;" OwnerUserId="11822" LastEditorUserId="543" LastEditDate="2021-12-04T16:52:22.167" LastActivityDate="2021-12-04T16:52:22.167" Title="What factors influence cloud height and type?" Tags="|meteorology|clouds|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="12929" PostTypeId="1" AcceptedAnswerId="12932" CreationDate="2017-12-18T16:22:38.773" Score="5" ViewCount="158" Body="&lt;p&gt;I read this article, &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.technologyreview.com/s/416786/global-warming-vs-the-next-ice-age/&quot; rel=&quot;noreferrer&quot;&gt;https://www.technologyreview.com/s/416786/global-warming-vs-the-next-ice-age/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;In about 300 years, all available fossil fuels may well have been consumed.Over the following centuries, excess carbon dioxide will naturally dissolve into the oceans or get trapped by the formation of carbonate minerals. Such processes won’t be offset by the industrial emissions we see today, and atmospheric carbon dioxide will slowly decline toward preindustrial levels. In about 2,000 years, when the types of planetary motions that can induce polar cooling start to coincide again, the current warming trend will be a distant memory.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2,000 years is a &lt;em&gt;lot&lt;/em&gt; sooner than other estimates, which can be in the hundreds of thousands of years, so is this an unrealistic estimate ?&lt;/p&gt;&#xA;" OwnerUserId="11238" LastEditorUserId="11908" LastEditDate="2019-03-14T01:00:47.960" LastActivityDate="2019-03-14T01:00:47.960" Title="Is 2,000 years from now a credible figure for return to glaciation?" Tags="|glaciology|glaciation|milankovitch-cycles|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12930" PostTypeId="1" CreationDate="2017-12-18T18:47:49.493" Score="10" ViewCount="1116" Body="&lt;p&gt;Recently, a colleague explained that the recent cold spell in the eastern United States could have been predicted using the Bering Sea Rule. The idea is that 17-21 days after a storm appears in the Bering Sea, a storm will appear in the United States. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Is this rule reliable? &lt;/li&gt;&#xA;&lt;li&gt;What is the explanation for it?&lt;/li&gt;&#xA;&lt;li&gt;What is the skill of a forecast using the Bering Sea Rule?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://wqad.com/2017/11/28/first-snow-may-not-arrive-until-week-before-christmas/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; is a news report that mentions it for the recent weather pattern.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2017-12-23T01:55:15.920" LastActivityDate="2018-01-05T21:19:20.250" Title="Can the Bering Sea Rule be used to predict the weather?" Tags="|meteorology|weather-forecasting|arctic|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12931" PostTypeId="2" ParentId="12930" CreationDate="2017-12-18T19:57:18.293" Score="10" Body="&lt;p&gt;There are two papers produced by the NOAA's National Weather Service investigating the claims regarding the Bering Sea Rule (BSR) and the Typhoon Rules for long range forecasts.  Some insite for your immediate questions:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Although not giving a percent reliability of the BSR, the second&#xA;study does say that the BSR has forecast skill above climatology for&#xA;long range forecasting - see Discussion, Summary and Conclusions&#xA;section of study II.&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;From paper I: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Bering Sea (BSR) and Typhoon (TR) rules are two observations used&#xA;  by weather forecasters. The former was introduced in 2011, while the&#xA;  latter has been used since at least the 1940s and are based on the&#xA;  idea of teleconnectivity within the Pacific Ocean region which was&#xA;  defined statistically by Wallace and Gutzler (1981). For example, the&#xA;  Pacific North American (PNA) pattern will be associated with&#xA;  alternating trough-ridge patterns from the Central Pacific to the East&#xA;  Coast of the US. A ridge-trough pattern from west to east over the US&#xA;  is a positive PNA configuration, while the opposite pattern is&#xA;  negative. Teleconnection is thought to be the result of downstream&#xA;  propagation of Rossby Wave activity in the North and South Pacific&#xA;  basins (e.g., Renwick and Revell, 1999; Wang et al. 2011, and&#xA;  references therein). The Bering Sea region is close to one&#xA;  teleconnective centers in the PNA pattern, which should make these&#xA;  rules useful indicators of weather downstream.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&lt;/li&gt;&#xA;&lt;li&gt;Refer to the Case Studies in study II.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Source (Study I): &lt;a href=&quot;http://www.nws.noaa.gov/ost/climate/STIP/39CDPW/39cdpw-JRenken.pdf&quot; rel=&quot;noreferrer&quot;&gt;http://www.nws.noaa.gov/ost/climate/STIP/39CDPW/39cdpw-JRenken.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source (Study II): &lt;a href=&quot;http://www.nws.noaa.gov/ost/climate/STIP/40CDPW/40cdpw-JRenken.pdf&quot; rel=&quot;noreferrer&quot;&gt;http://www.nws.noaa.gov/ost/climate/STIP/40CDPW/40cdpw-JRenken.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2017-12-18T19:57:18.293" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12932" PostTypeId="2" ParentId="12929" CreationDate="2017-12-19T04:48:43.790" Score="4" Body="&lt;p&gt;It's a little dated and brief, but it's a cool article and I believe it's overall sound in it's predictions and arguments presented.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the overall point, the author isn't predicting an ice age in 2,000 years, so the answer to your title question is that he didn't really say that, though he writes the article somewhat poorly because that's not very clear, especially when he writes the words &quot;double whammy&quot;.   But he's predicting a natural correction to the added CO2 within about 2,000 years, after which the glaciation cycle, but not necessarily an ice age, should return.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The next ice age is hard to predict because Earth's Milankovich cycles aren't adding up right for another 150,000 years, so if an ice age can be triggered by a small push, one could happen in 10,000 years, but a big push isn't due for some time.   &lt;a href=&quot;https://earthscience.stackexchange.com/questions/6653/when-will-glaciation-resume-has-global-warming-delayed-return-to-global-cooling&quot;&gt;More details on the timing of the next glaciation here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your author's primary point is that man made climate change won't prevent the next ice age because the Earth will reabsorb the CO2 before then.   He may be right, and I think that's a very sound and fair point to make.  He's not actually saying an ice age will begin in about 2,000 years, though he does seem to imply the possibility.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think, 2,000 years is likely too soon.   The triggering of ice ages requires cold northern hemisphere summers (He says that in his article too).  Basically, &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/9/90/InsolationSummerSolstice65N.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;the red line on this chart should be low&lt;/a&gt;, and we're in a leveling off and small warming period for the next 50,000 years.  The cycles are adding up in such a way that predicting the next ice age is hard.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;On his predictions:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Predicting that mankind will run out of fossil fuels in 300 years is reasonable.   It's something that can't be predicted with accuracy and I personally think it's wrong.   I think we'll move away from coal as climate change gets worse and with abundant deep shale that can be fracked (natural gas is good for cooking and planes need fossil fuels), so I think fossil fuels will remain in use and to some extent, untapped considerably past 300 years, but my opinion aside, his prediction is still reasonable and possible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Predicting that it will take the Earth about 2,000 years to reabsorb the added CO2 is also reasonable.  I don't think anyone knows how long, or if a new equilibrium will be reached as opposed to a return to how it was, and making this kind of prediction is replete with uncertainties, but 2,000 years is fair.   We should keep in mind that a science based hypothesis can be reasonable and still end up being wrong.   In science as &quot;good&quot; hyopthesis is one that can be tested.   A &quot;good&quot; hypothesis can still be wrong and for estimates this far out, there's room for both his estimate being reasonable and his estimate being very far off the mark.    People sometimes yell at scientific predictions for being wrong, but predicting the future is hard, and people should stop yelling about that because it's not helpful.   Scientists know that not all hypothesis based predictions are accurate, what matters is that a prediction is science based, has correlated cause and effect and can be studied and tested.   (I hope you forgive my little rant, but I wanted to say what a good hypothesis actually means).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some studies on oceanic absorption of CO2 and other estimates of how long it would take for the Earth to recover might improve this answer, or be the subject for another question, but I'm not feeling the urge right now.   That's a tricky thing to estimate and 2,000 years seems fair enough to me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's funny that, today, it's in our best interest to try to stop using fossil fuels, but if/when the next ice age is coming, people might be encouraged to use clean fossil fuels to release more CO2 and prevent the coming ice age.   &quot;go for a drive, it's good for the environment&quot; . . . anyone who's still around in 100,000 years, feel free to put that on your bumper-sticker.   The author also indirectly makes the point that we might want to save some of our fossil fuels as a means of ice-age prevention.   It's a sound point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think the article should have been longer and more fleshed out, but it's a good basic article.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also want to add that while the article is short, he has a 267 page e-book which I imagine, goes into more detail.   &lt;a href=&quot;https://books.google.com/books/about/Energy_Demand_and_Climate_Change.html?id=EdAgjDtBsNsC&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://books.google.com/books/about/Energy_Demand_and_Climate_Change.html?id=EdAgjDtBsNsC&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2017-12-19T04:54:48.313" LastActivityDate="2017-12-19T04:54:48.313" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="12933" PostTypeId="2" ParentId="12527" CreationDate="2017-12-19T10:52:15.983" Score="13" Body="&lt;p&gt;I made some pictures on my tablet to explain everything a bit better. Sorry that they are not that nice.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Shuffle&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;If we do not us shuffle, we store on value (float, double, integer, short integer, ...) after another. Thus, each variable itself is stored contiguously in memory. The first bit of a second value follows the last bit of the first value. If we use shuffle, the first bit of &lt;em&gt;all&lt;/em&gt; variables is stored contiguously in space, followed by the second bit, and so on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vVKba.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vVKba.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The figure above shows an array of six 8-bit integers (only 8-bit because it was less painting work ;-) ). The vertical black boxes split in 8 compartments represents on 8-bit integer. The orange arrows from left to right indicate how the bits would be stored with shuffling.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now we assume some example values: We have an array with the values 4, 2, 4, 5, 7, and 6. It is shown in the figure below. The first row shows the decimal representation. The matrix below is the binary representation. Each binary column represents the corresponding decimal number in the first row. The red arrows indicates the &lt;em&gt;normal&lt;/em&gt; storage order. The orange arrows indicate the &lt;em&gt;shuffled&lt;/em&gt; storage order. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GiIHq.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GiIHq.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now we can write down the order of bits in the memory. I wanted to use color. Therefore, you get another picture:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/uEVA7.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uEVA7.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We have a lot of zeros in the beginning of the binary representation of each value (because we have very low values). The shuffling is favorable in this situation because we have a long contiguous memory part filled with the same &lt;em&gt;number/condition&lt;/em&gt; (= 0).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we had no low numbers but higher numbers, (but) which are close to each other, we would not have a long contiguous memory part filled with 0s (zeros) but it might be six 1s and then six 0s. Commonly in netCDF files we have much larger arrays. Lets say a 4-dim array with 100 x 200 x 30 x 365 values, which are quite similar to each other. Then we would have often 2.19 x 10&lt;sup&gt;9&lt;/sup&gt; contiguous 1s or 0s in memory, which is quite nice for compression.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, if neighboring values differ considerably, shuffling might not be a good idea.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Chunking&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;If we have an uncompressed file (= no chunking; or one big chunk), a n-dim array is stored contiguously in memory: at first all values of the first row (first index) of the array are stored contiguously in memory; then we go to the next row (increment second index by one) and write the second row contiguously into the memory; and so on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We might also start with the last index and do it the other way around ... - depending on the programming language and on the definition of what are &lt;em&gt;rows&lt;/em&gt; and &lt;em&gt;columns&lt;/em&gt;. But the principle is the same.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The figure below shows an example for a 2-dim variable with one spatial and one temporal dimension. The red arrows indicate how the data is aligned in memory. The black dots are individual values in our 2-dim array.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dF1Fh.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dF1Fh.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, we want to extract a time slice (all spatial values at one time step) and a space slice (all temporal values at one location) from our data. In the second case we get a time series (could be a time series of model data). In the first case we get a picture of the current situation (could be for a map). The blue and green markings in the figure below indicate the time and space slices.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xrPPI.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xrPPI.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The difference between time and space slice is the following. The time slice is fast to extract because the values are stored contiguously in memory. The space slices takes more time because only each sixth value is extracted. Is this example the extra &lt;em&gt;work/time&lt;/em&gt; spend is low. However, if we have a large 4-dim variable, the time-slice-extraction will be faster than the space-slice-extraction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When we compress data, we can chunk it. That means, that we split our large array-variable in sub-arrays. For the user it looks the same from the outside. netCDF-4 does chunking automatically, when we compress data but don't define a chunking pattern.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The figure below shows an example, in which our data was split into three chunks. The red arrows indicate the alignment of our values in the memory. This is just an exemplary alignment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8zKfn.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8zKfn.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, we extract time and space slices again (figure below). Green and blue indicate the slices, again. Here we see that the space-slice will be much &lt;em&gt;easier/faster&lt;/em&gt; to extract then before. However, the extraction of the time slice will take more time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9fp1t.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9fp1t.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition, the compression will differ when you change the chunk sizes. The background is similar as described in the &lt;em&gt;&lt;strong&gt;Shuffle&lt;/strong&gt;&lt;/em&gt; section: depending on which values are neighboring each other, the one or the other chunking might be favorable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now to your question: &lt;em&gt;&lt;strong&gt;what's the best choice of chunk size?&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;focus on usage&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;It depends on your data usage and you access pattern. If you often extract time series at specific locations, it might be favorable to define the chunks in a way that the values corresponding to one location are close to each other aligned in memory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But be careful, some software like cdo access the netCDF data always in the same way - independent of what you do with it during the processing. Thus, if you don't access the file directly via the C- or Fortran-netCDF4 routines but via some other software, the &lt;em&gt;best&lt;/em&gt; chunking pattern might not depend on what you want to do but how the software does it ... . Some software might - for example - always read data along the spatial dimensions first, although you want data along the time dimension.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;focus on compression:&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The size of the compressed file varies with the chunking layout. The situation is similar as described in the Shuffle section. If the data are more effective to compress in time dimension, the chunking in my example figure above might be favorable for file size (e.g. high variability in space but low variability in time).&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Chunking summary&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The best choice of the chunk size depends on your access pattern, on the software you use, on your data itself, and on your focus on &lt;em&gt;access time vs. storage space&lt;/em&gt;. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Compression level&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The choice of the compression level depends on your aim. If you just want to store the data (in an archive or where-ever) and have it as small as possible, you might use compression level 9.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to access data often and fast, you should choose a lower compression level. We use compression levels up to 4. Above that the reduction in file size is very low (for us) so that we do not have a reason to go beyond.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Example:&lt;/strong&gt; Currently, I work with an ocean model. We have a lot of land in our model domain (roughly 1/3). Compression of level 1 is sufficient to reduce the file size by approximately 95%. However, this is a special case.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;summary:&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;I tried to give an overview of the features you asked for. The exact choice depends on you particular use case and cannot be generalized. For you, my answer might be too late but I hope that it might help some others. For me, the document you linked helped a lot in the past.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2017-12-19T10:52:15.983" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12937" PostTypeId="1" CreationDate="2017-12-20T11:10:30.437" Score="3" ViewCount="80" Body="&lt;p&gt;When or if the current interglacial ends, what sort of extinction level can we expect, and what sort of organisms and ecosystems are affected ?&#xA;How does this compare with the current extinction rate, both in the past and potentially in the future ?&#xA;Will species loss due to glaciation include the things we are currently trying to conserve ?&lt;/p&gt;&#xA;" OwnerUserId="11238" LastEditorUserId="11238" LastEditDate="2017-12-20T11:17:16.447" LastActivityDate="2017-12-20T11:17:16.447" Title="How does extinction caused by human activity compare to extinction caused by glaciation?" Tags="|mass-extinction|" AnswerCount="0" CommentCount="14" ContentLicense="CC BY-SA 3.0" />
  <row Id="12939" PostTypeId="1" CreationDate="2017-12-21T05:25:55.743" Score="3" ViewCount="4850" Body="&lt;p&gt;Is there an association with thrust fault or dormant volcanos and quartz veins? Where are quartz veins likely to occur in nature and how are the formed?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it possible to identify these veins from satellite images. &lt;/p&gt;&#xA;" OwnerUserId="11565" LastEditorDisplayName="user12525" LastEditDate="2019-09-01T14:26:50.770" LastActivityDate="2019-09-01T14:26:50.770" Title="How do quartz veins form?" Tags="|volcanology|petrology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12940" PostTypeId="2" ParentId="12765" CreationDate="2017-12-21T08:40:03.787" Score="1" Body="&lt;p&gt;Two approaches:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Search tourist websites for the countries you are interested in. They very often have average data on temperature and rainfall by month.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Just Google &lt;em&gt;countryname monthly rainfall&lt;/em&gt;. You may get general descriptions instead of hard (tabular) data, but since you only have to collect the data once, that's doable.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;But as you get from the comments below your post, how useful that data is remains doubtful.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an example: The &lt;a href=&quot;http://www.austria.org/climate/&quot; rel=&quot;nofollow noreferrer&quot;&gt;first hit&lt;/a&gt; for the &lt;a href=&quot;https://www.google.nl/search?q=austria+monthly+rainfall&quot; rel=&quot;nofollow noreferrer&quot;&gt;austria monthly rainfall&lt;/a&gt; search says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... &lt;strong&gt;altitude&lt;/strong&gt; determines the precipitation pattern; while high-level areas in the Alps may have a high average rainfall in excess of 2000 mm per year, while some regions in the flatlands of Austria have only 600 mm annually.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;(emphasis mine)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that this page mentions the &lt;a href=&quot;http://www.weatheronline.co.uk/reports/climate/&quot; rel=&quot;nofollow noreferrer&quot;&gt;WeatherOnline (UK) Climate of the world&lt;/a&gt; page as its source. There you have descriptions for many countries.&lt;/p&gt;&#xA;" OwnerUserId="595" LastActivityDate="2017-12-21T08:40:03.787" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12941" PostTypeId="2" ParentId="12939" CreationDate="2017-12-21T09:44:58.157" Score="7" Body="&lt;p&gt;The formation of quartz veins needs fluids enriched in Si. Usually Si dissolves somewhere in neighbouring formations, gets transported by fluids and precipitates where the fluid pressure is low (the fluids Si-saturation capacity decreases with decreasing fluid pressure).&#xA;Fluid pressure is usually involved in rock fracturing. When it builts-up, it can fracture the rock. Thereby generated fractures, in turn, accomodate void space, hence the fluid pressure drops and Si precipitates from the fluid to form veins. These veins reseal and restrengthen the rock, which can again lead to a renewed fluid pressure built-up. This process is known as crack-seal vein formation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Usually, crack-seal vein formation happens progressively, which is a very nice thing: Studying vein internal mineral structures gives evidence to past stress regime conditions. These evidences can help unraveling the evolution of tectonic structures, such as mountain formations or fault systems.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quartz veins are very common, they need a source of disolvable Si, which is a really abundant element. In carbonate rocks, calcite veins are more common. The crack-seal principle applies for them just the same. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, you can see veins in satelite pictures! Have a look here: &lt;a href=&quot;https://www.google.de/maps/place/Oman/@23.2730986,57.1338697,412m/data=!3m1!1e3!4m5!3m4!1s0x3dd69f66a9d59bbf:0x3a064c7665b1a817!8m2!3d21.4735329!4d55.975413?hl=de&quot; rel=&quot;noreferrer&quot;&gt;OMAN&lt;/a&gt; (These are calcite veins standing out against a darker limestone).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this helps,&#xA;Ben&lt;/p&gt;&#xA;&#xA;&lt;p&gt;P.S.: You might want to have a look at my thesis on (calcite) vein-networks in Oman: &lt;a href=&quot;http://publications.rwth-aachen.de/record/230296&quot; rel=&quot;noreferrer&quot;&gt;LINK&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6152" LastEditorUserId="6152" LastEditDate="2017-12-21T13:32:42.373" LastActivityDate="2017-12-21T13:32:42.373" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12942" PostTypeId="2" ParentId="12939" CreationDate="2017-12-21T10:01:58.790" Score="3" Body="&lt;p&gt;Quarz veins come in different sizes - starting from milimetre scale ending with several meters (if not more). Quartz veins form from aqueous solution and in most cases that is associated with high hydraulic pressure (be that because of deformation or volcanic fluids). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is highly unlikely that you could identify veins from satelite images because of their size and vegetation. On the other hand that might be possible using drone photos.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suggest looking at Cabo de Gata (cape of agate) satelite images as an example of volcanic region with plenty of silica veins and very little of vegetation. The veins there usually smaller than 1 meter so I don't expect you to see them but you can see some cracks in the rock, which occasionally are refiled with silica (coordinates 36°46'57.3&quot;N 2°06'02.8&quot;W) (source: I did mapping there)&lt;/p&gt;&#xA;" OwnerUserId="11156" LastActivityDate="2017-12-21T10:01:58.790" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12943" PostTypeId="2" ParentId="12913" CreationDate="2017-12-21T13:54:58.880" Score="3" Body="&lt;p&gt;Here is a map of seismic hazards for the United States from the United States Geological Survey. &lt;a href=&quot;https://earthquake.usgs.gov/hazards/hazmaps/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Link&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Q3TEy.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Q3TEy.jpg&quot; alt=&quot;Seismic hazard map for the lower US&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://usgs.maps.arcgis.com/apps/webappviewer/index.html?id=db287853794f4555b8e93e42290e9716&quot; rel=&quot;nofollow noreferrer&quot;&gt;Link&lt;/a&gt; to interactive fault map for the US (source: USGS)&#xA;Here is a &lt;a href=&quot;https://www.wired.com/2008/10/five-us-earthqu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt; to a nice article on top 5 earthquake prone areas outside California.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is presence of fault zones, geological structures (like volcanos, subduction zones, tectonic plate junctions, basins, and mountains), geological evidence of past events, and record of earthquake events that go into the calculation of a seismic hazard for a specific region.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="1149" LastEditDate="2017-12-21T14:01:34.093" LastActivityDate="2017-12-21T14:01:34.093" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12944" PostTypeId="2" ParentId="12913" CreationDate="2017-12-21T16:02:35.927" Score="2" Body="&lt;p&gt;Here are a few links that may help out with your question:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthquake.usgs.gov/hazards/qfaults/map/#qfaults&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earthquake.usgs.gov/hazards/qfaults/map/#qfaults&lt;/a&gt;  &lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.cbc.ca/beta/news/multimedia/every-fault-line-in-british-columbia-1.2919420&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.cbc.ca/beta/news/multimedia/every-fault-line-in-british-columbia-1.2919420&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="11565" LastEditorUserId="6298" LastEditDate="2017-12-22T10:09:45.370" LastActivityDate="2017-12-22T10:09:45.370" CommentCount="0" CommunityOwnedDate="2017-12-21T16:02:35.927" ContentLicense="CC BY-SA 3.0" />
  <row Id="12945" PostTypeId="2" ParentId="10625" CreationDate="2017-12-21T16:45:57.130" Score="3" Body="&lt;p&gt;Expanding on Friddy's third point, this could be the surface signature of what are called internal waves (&lt;a href=&quot;https://en.wikipedia.org/wiki/Internal_wave&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Internal_wave&lt;/a&gt;). The smooth regions indicate upward motion of internal waves and the rough regions indicate downward motion of internal waves. More information can be found here: &lt;a href=&quot;http://www.whoi.edu/oceanus/feature/the-waves-within-the-waves&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.whoi.edu/oceanus/feature/the-waves-within-the-waves&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11269" LastActivityDate="2017-12-21T16:45:57.130" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12946" PostTypeId="1" CreationDate="2017-12-21T22:22:21.273" Score="1" ViewCount="145" Body="&lt;p&gt;Would it be possible to build a massive seawall, say maybe even made from metal that could rise as the sea level rises to prevent being erased? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not considering costs here, nor beauty, only if such a wall would be able to resist the force of the entire ocean trying to get into the &quot;empty&quot; pool. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Is it feasible?&lt;/li&gt;&#xA;&lt;li&gt;What kind of material would be required? How high could one go? &lt;/li&gt;&#xA;&lt;li&gt;In the event of a leak, &quot;terrorist&quot; assault, what kind of disasters and how quickly would the Island become &quot;erased&quot;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;You can give an example approximation on the size of the Island. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just theoretical.&lt;/p&gt;&#xA;" OwnerUserId="11843" LastEditorUserId="5594" LastEditDate="2017-12-22T14:32:49.057" LastActivityDate="2017-12-22T14:32:49.057" Title="Building massive seawall around endangered Islands like Mauritius to save from climate change" Tags="|climate-change|climate|co2|" AnswerCount="1" CommentCount="1" ClosedDate="2017-12-29T12:29:20.323" ContentLicense="CC BY-SA 3.0" />
  <row Id="12947" PostTypeId="2" ParentId="12946" CreationDate="2017-12-22T08:07:46.200" Score="5" Body="&lt;p&gt;This is more of an engineering question. For some situations it may be possible to build such a wall around some islands. Such a sea wall would be a &lt;a href=&quot;https://en.wikipedia.org/wiki/Cofferdam&quot; rel=&quot;noreferrer&quot;&gt;cofferdam&lt;/a&gt;, which have been used for small scale temporary projects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Complicating factors would be:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The height of the sea wall and how much water would need to be held back. &lt;/li&gt;&#xA;&lt;li&gt;The depth of to the sea floor. If the island is the tip of a &lt;a href=&quot;https://en.wikipedia.org/wiki/Seamount&quot; rel=&quot;noreferrer&quot;&gt;seamount&lt;/a&gt; with steep sides and a large depth to the sea floor then a sea wall would be impossible.&lt;/li&gt;&#xA;&lt;li&gt;The depth into the sea bed that the wall would need to be anchored into, or the wall would need to sink into, for the wall to be stable.&lt;/li&gt;&#xA;&lt;li&gt;The wall would have to be able to withstand typhoons/cyclones/hurricanes,  small tsunamis and seismic events.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;A metal wall would not be a long term solution due to corrosion of the metal. The most suitable material would be rock or concrete. Such a wall would need to be very wide. However, over time, even such a wall would need to be replaced/repaired due to sea erosion and battering.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Securing the wall against leaks would be critical and such a system may require solar power pumps to continuously move excess water out of the enclosure.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="6298" LastEditDate="2017-12-22T10:07:11.410" LastActivityDate="2017-12-22T10:07:11.410" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12948" PostTypeId="1" CreationDate="2017-12-22T09:31:18.133" Score="1" ViewCount="59" Body="&lt;p&gt;I have taken the following synthetic seismogram, generated using Marmousi model, from the &lt;a href=&quot;http://www.ahay.org/RSF/book/xjtu/modeling2fwi/paper_html/node11.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Madagascar website&lt;/a&gt;.&#xA;I could not understand the origin of linear events (present in shot3 after 2 sec) and similarly in shot 7 at 2sec.&#xA;Any help is appreciated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sB6DF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sB6DF.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5413" LastEditorUserId="5413" LastEditDate="2017-12-22T10:17:45.090" LastActivityDate="2017-12-22T10:17:45.090" Title="Problem in identification of seismic event?" Tags="|seismology|seismic|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12949" PostTypeId="2" ParentId="12483" CreationDate="2017-12-23T02:12:41.593" Score="2" Body="&lt;p&gt;This rock looks very similar to a Petoskey stone which is the state rock of Michigan.  The rock is made of the six sided coral &lt;em&gt;Hexagonaria percarinata&lt;/em&gt;.  They were deposited in this area during the Pleistocene glaciation around 2 million years ago.  This fossil is distinctive of the Travis group strata in the Petoskey and Charlevoix regions of Michigan. They come in many sizes and the hexagonal patterns really pop when wet or polished.  More information can be found at the wikipedia link below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kTz44.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kTz44.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Petoskey_stone&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Petoskey_stone&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2017-12-23T02:12:41.593" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12951" PostTypeId="1" AcceptedAnswerId="12957" CreationDate="2017-12-23T16:44:29.600" Score="3" ViewCount="955" Body="&lt;p&gt;Someone recently claimed in my hearing that if the Yellowstone caldera were to erupt, the resulting ash cloud would end all agriculture for a year or two. (The speaker is not a scientist, and neither am I.) &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Is that accurate?&lt;/li&gt;&#xA;&lt;li&gt;Are there &lt;em&gt;reasonable&lt;/em&gt; scenarios (i.e., not &lt;a href=&quot;http://www.imdb.com/title/tt0120461/?ref_=fn_al_tt_1&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;) worked out for the effects of a supervolcano eruption?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I did see &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9509/yellowstone-eruption-possibility&quot;&gt;this question&lt;/a&gt;, where one of the commenters points out that such an event would be unprecedented, so our ability to predict is limited, but I'm still curious about whatever we do know at this stage.&lt;/p&gt;&#xA;" OwnerUserId="11852" LastActivityDate="2017-12-25T12:07:03.267" Title="Would a Yellowstone eruption destroy global agriculture?" Tags="|volcanology|volcanic-hazard|volcanic-eruption|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12952" PostTypeId="1" CreationDate="2017-12-24T15:32:26.883" Score="2" ViewCount="387" Body="&lt;p&gt;Can any one help me to handle huge netcdf files each of 1gb memory in loop and at least 2 files at a time in ncl or linux or python or matlab.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;for example era_interim daily pressure level datasets.&lt;/p&gt;&#xA;" OwnerUserId="11856" LastEditorUserId="111" LastEditDate="2017-12-24T16:19:19.710" LastActivityDate="2017-12-26T13:27:34.373" Title="Huge netcdf files handling" Tags="|climatology|netcdf|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="12953" PostTypeId="2" ParentId="12952" CreationDate="2017-12-24T16:21:52.087" Score="1" Body="&lt;p&gt;One option is to not load the entire file at a time. You can use &lt;a href=&quot;https://code.google.com/archive/p/nctoolbox/wikis/ncgeodataset.wiki&quot; rel=&quot;nofollow noreferrer&quot;&gt;ncgeodataset&lt;/a&gt;. The routine allows for the extraction of a subset of data without having to load the entire file or even an array into Matlab. It is great for large datasets.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2017-12-24T16:21:52.087" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12954" PostTypeId="1" AcceptedAnswerId="12958" CreationDate="2017-12-25T04:43:06.390" Score="6" ViewCount="433" Body="&lt;p&gt;The recent paper in Nature &lt;a href=&quot;https://www.nature.com/articles/nature25031&quot; rel=&quot;noreferrer&quot;&gt;The divergent fates of primitive hydrospheric water on Earth and Mars&lt;/a&gt; (Nature 552, 391–394 (21 December 2017)&#xA;doi:10.1038/nature25031) has been linked by many recent news articles. Essentially much of Mars' original surface water may have been incorporated into metamorphic rock, rather than lost to space following the collapse of it's magnetic field then followed by it's atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is suggested that the higher iron content of surface minerals on Mars relative to that of Earth lead to enhanced serpentinization.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm having a hard time understanding the use of the term &lt;em&gt;serpentinization&lt;/em&gt; as used in the abstract of the Nature paper shown below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wikipedia shows a &lt;a href=&quot;https://en.wikipedia.org/wiki/Serpentine_subgroup&quot; rel=&quot;noreferrer&quot;&gt;serpentine subgroup&lt;/a&gt; of minerals and the mineral &lt;a href=&quot;https://en.wikipedia.org/wiki/Serpentinite&quot; rel=&quot;noreferrer&quot;&gt;serpentinite&lt;/a&gt; itself, as well as an &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Folded_serpentinite.jpg&quot; rel=&quot;noreferrer&quot;&gt;image of a rock formation with serpentine patterns&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this context, does &lt;em&gt;serpentinization&lt;/em&gt; just refer to the formation of some hydrated minerals that happen to be of a class that is historically been referred to as serpentinite or it's subgroup, or is &lt;em&gt;serpentinization&lt;/em&gt;  a process that always produces serpentine patterns?&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Despite active transport into Earth’s mantle, water has been present on our planet’s surface for most of geological time. Yet water disappeared from the Martian surface soon after its formation. Although some of the water on Mars was lost to space via photolysis following the collapse of the planet’s magnetic field, the widespread serpentinization of Martian crust suggests that metamorphic hydration reactions played a critical part in the sequestration of the crust. Here we quantify the relative volumes of water that could be removed from each planet’s surface via the burial and metamorphism of hydrated mafic crusts, and calculate mineral transition-induced bulk-density changes at conditions of elevated pressure and temperature for each. The metamorphic mineral assemblages in relatively FeO-rich Martian lavas can hold about 25 per cent more structurally bound water than those in metamorphosed terrestrial basalts, and can retain it at greater depths within Mars. Our calculations suggest that in excess of 9 per cent by volume of the Martian mantle may contain hydrous mineral species as a consequence of surface reactions, compared to about 4 per cent by volume of Earth’s mantle. Furthermore, neither primitive nor evolved hydrated Martian crust show noticeably different bulk densities compared to their anhydrous equivalents, in contrast to hydrous mafic terrestrial crust, which transforms to denser eclogite upon dehydration. This would have allowed efficient overplating and burial of early Martian crust in a stagnant-lid tectonic regime, in which the lithosphere comprised a single tectonic plate, with only the warmer, lower crust involved in mantle convection. This provided an important sink for hydrospheric water and a mechanism for oxidizing the Martian mantle. Conversely, relatively buoyant mafic crust and hotter geothermal gradients on Earth reduced the potential for upper-mantle hydration early in its geological history, leading to water being retained close to its surface, and thus creating conditions conducive for the evolution of complex multicellular life.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2017-12-25T12:34:24.523" Title="What is serpentinization, in the context of disappearance of surface water on Mars?" Tags="|mineralogy|hydrogeology|mars|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12955" PostTypeId="1" CreationDate="2017-12-25T07:02:13.287" Score="5" ViewCount="153" Body="&lt;p&gt;What concentrations of magnesium, sodium and sulfate are needed to precipitate solid MgSO&lt;sub&gt;4&lt;/sub&gt; and Na&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt; (let's say evaporation is occurring in a system) I'm assuming probably really high because they are soluble salts? But can someone tell me in mg/L how much? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm asking because in this paper I read the authors are claiming magnesium and sodium in solution are coming from dissolution of MgSO&lt;sub&gt;4&lt;/sub&gt; and Na&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt; but the concentrations are really low... like 20 mg/L of each. If those minerals were present wouldn't concentrations of Mg and Na be much higher?&lt;/p&gt;&#xA;" OwnerUserId="11858" LastEditorUserId="28050" LastEditDate="2018-01-08T17:03:20.210" LastActivityDate="2018-01-08T17:03:20.210" Title="Sulfate salts of magnesium and sodium" Tags="|geochemistry|mineralogy|minerals|evaporation|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12956" PostTypeId="2" ParentId="12954" CreationDate="2017-12-25T08:37:10.213" Score="5" Body="&lt;p&gt;&lt;a href=&quot;http://www.sandatlas.org/serpentinite/&quot; rel=&quot;noreferrer&quot;&gt;Serpentinization&lt;/a&gt; is a system of,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;chemical reactions which convert anhydrous ferromagnesian silicate minerals (pyroxene, olivine) into hydrous silicate minerals (serpentine) plus some other possibilities like brucite and magnetite. Brucite forms if the precursor rocks are rich in magnesium (dunite, for example). Magnetite forms if there is enough iron present (pyroxenite). Usually serpentinite contains iron in the form of magnetite which gives dark color to serpentinites.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In short, serpenitinization about the formation of hydrated silicate minerals not about the formation of snake (serpent) like skin patterns on rock.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-12-25T08:37:10.213" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12957" PostTypeId="2" ParentId="12951" CreationDate="2017-12-25T12:07:03.267" Score="2" Body="&lt;p&gt;An eruption of the Yellowstone &lt;a href=&quot;https://en.wikipedia.org/wiki/Supervolcano&quot; rel=&quot;nofollow noreferrer&quot;&gt;super volcano&lt;/a&gt; would cause agricultural disaster over a very large area. Its global effect would be significant, but &lt;a href=&quot;https://www.livescience.com/20714-yellowstone-supervolcano-eruption.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;not totally devastating&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The resulting climate cooling could last up to a decade. The temporary climate shift could alter rainfall patterns, and, along with severe frosts, cause widespread crop losses and famine.&lt;/p&gt;&#xA;&lt;p&gt;But a Yellowstone megablast would not wipe out life on Earth. There were no extinctions after its last three enormous eruptions, nor have other supereruptions triggered extinctions in the last few million years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Eruption of super volcanoes is rare which makes it difficult to ascertain what exactly would happen when the Yellowstone super volcano eventually erupts - which won't be any time soon.&lt;/p&gt;&#xA;&lt;p&gt;Yellowstone last erupted &lt;a href=&quot;https://www.nps.gov/yell/learn/nature/volcanoqa.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;174 000 years ago&lt;/a&gt;, which was a minor eruption. Lava from Yellowstone won't be the problem, but the ash and gases will be.&lt;/p&gt;&#xA;&lt;p&gt;The last major eruption, 630 000 years ago, covered much of western and central United States with ash. The maximum thickness of the ash from that eruption is &lt;a href=&quot;https://www.forbes.com/sites/trevornace/2017/10/26/yellowstone-volcano-eruptions-caldera-global-climate/#bee37232afaf&quot; rel=&quot;nofollow noreferrer&quot;&gt;660 ft&lt;/a&gt;. The eruption was a double eruption, 170 years apart. The amount of ash thrown into the atmosphere with each eruption caused the ocean to cool by 3 degrees Celsius with each eruption.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-12-25T12:07:03.267" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12958" PostTypeId="2" ParentId="12954" CreationDate="2017-12-25T12:22:54.257" Score="7" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;does serpentinization just refer to the formation of some hydrated minerals that happen to be of a class that is historically been referred to as serpentinite or it's subgroup&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Yes. In simple terms, the reaction is enstatite + forsterite + water = serpentine.&lt;/p&gt;&#xA;&lt;p&gt;MgSiO&lt;sub&gt;3&lt;/sub&gt; + Mg&lt;sub&gt;2&lt;/sub&gt;SiO&lt;sub&gt;4&lt;/sub&gt; + 2H&lt;sub&gt;2&lt;/sub&gt;O = Mg&lt;sub&gt;3&lt;/sub&gt;Si&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt;(OH)&lt;sub&gt;4&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;Forsterite and enstatite (or more generally, olivine and pyroxene) are common minerals in mafic igneous rocks. The formation of serpentine locks up water in the resulting solid crystal structure.&lt;/p&gt;&#xA;&lt;p&gt;You can see more examples of serpentine forming reactions on page 5 of &lt;a href=&quot;http://www.ifa.hawaii.edu/UHNAI/NAIweb/presentations/Mariana%20Forearc.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this PDF file&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;or is serpentinization a process that always produces serpentine patterns?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;No. There is no such thing as &amp;quot;serpentine patterns&amp;quot;. The image you link to is of &amp;quot;folded serpentinite&amp;quot;. The &amp;quot;serpentinite&amp;quot; bit of it are the green layers, regardless of whether they are folded or  not. The nice photogenic folded part is a later tectonic event that is unrelated to the formation of the serpentinite.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2017-12-25T12:34:24.523" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12959" PostTypeId="2" ParentId="12955" CreationDate="2017-12-25T12:32:54.563" Score="1" Body="&lt;p&gt;Solubilities (taken from Wikipedia):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;MgSO&lt;sub&gt;4&lt;/sub&gt;: 35.1 g/100 mL (20 °C)&lt;/li&gt;&#xA;&lt;li&gt;Na&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;4&lt;/sub&gt;: 13.9 g/100 mL (20 °C)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;It does seem that the solubilities should be  an order of magnitude higher than  is quoted in the paper you are reading.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Several ideas:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The paper is wrong.&lt;/li&gt;&#xA;&lt;li&gt;You did not understand the paper correctly.&lt;/li&gt;&#xA;&lt;li&gt;The solubilities mentioned above are of the pure compound in pure water. If it's in an evaporite basin the the chemistry of the water might differ and the solubilities might also differ.&lt;/li&gt;&#xA;&lt;li&gt;As an example, the presence of a more soluble salt will cause the less soluble salt to be come even more soluble (a process called &quot;salting-out&quot;). For instance, if you have an almost saturared solution of NaCl, and you add CaCl&lt;sub&gt;2&lt;/sub&gt;, a more soluble salt, you will start preciptating NaCl once enough CaCl&lt;sub&gt;2&lt;/sub&gt; is added to the system.&lt;/li&gt;&#xA;&lt;li&gt;There could be other anions in the system which make Na and Mg less soluble. Borates? Phosphates? Carbonates? Fluorides? The solubility is determined by the least soluble component of the system. Adding sulfate to magnesium silicate isn't going to do much to it in terms of solubility (unless it is sulfuric acid of course).&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="725" LastActivityDate="2017-12-25T12:32:54.563" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12960" PostTypeId="1" AcceptedAnswerId="13026" CreationDate="2017-12-25T14:55:16.763" Score="4" ViewCount="1391" Body="&lt;p&gt;What is the intuition behind acoustic impedance? Yes, I know that it is the opposition to a seismic wave travelling in the medium. But why it is defined as density &amp;times; velocity?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The velocity of a seismic wave depends on density, so why not use only the velocity contrast or density contrast between layers instead of the impedance contrast?&lt;/p&gt;&#xA;" OwnerUserId="11861" LastEditorUserId="28050" LastEditDate="2018-01-04T19:08:33.557" LastActivityDate="2018-01-04T19:08:33.557" Title="Acoustic impedance in geophysical context" Tags="|geology|geophysics|seismology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12961" PostTypeId="1" CreationDate="2017-12-25T22:00:54.960" Score="3" ViewCount="746" Body="&lt;p&gt;I have a problem with my project and I was hoping I would find some clarification. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I did some modeling with phreeqc to calculate saturation indices and found that  calcite was saturated in an engineered aquifer. The time of sampling of groundwater was roughly 1 year after construction was completed. Gypsum is present in the aquifer, so there are high calcium concentrations. However, I don't think the mineral calcite is actually forming insitu. I think the concentrations of calcium and carbonate are just at the right combination to be in equilibrium with calcite, so it is not actually contributing to calcium concentrations. I should add that the pH of the aquifer is between 7-8. I just don't think any sufficient quantities of calcite would form in a system with lots of water moving through it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this a correct interpretation? &lt;/p&gt;&#xA;" OwnerUserId="11858" LastActivityDate="2018-01-02T06:49:09.383" Title="Saturation Index clarification" Tags="|geochemistry|mineralogy|minerals|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12962" PostTypeId="2" ParentId="12960" CreationDate="2017-12-26T10:04:35.227" Score="3" Body="&lt;p&gt;This concept actually comes from the electrical. They define the impedance as $Z=\frac{V}{I}$. &#xA;Where V is potential difference/ voltage and I is current.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In acoustics, a similar expression can be obtained using the plane wave equation. &#xA;Since,&lt;br&gt;&#xA;                $$\partial_t V = -\rho^{-1}\partial_xP$$&#xA;where $P$ is pressure and $V$ is velocity.&#xA;Now take fourier transform of both sides and defined impedance as $$Z(\omega)= \frac{P(\omega)}{V(\omega)} = \rho c$$&#xA;Where, obviously, $P$ is analougous to potential difference and $V$ is analougous to current.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You may refer to any wave theory book for details.&lt;/p&gt;&#xA;" OwnerUserId="5413" LastEditorUserId="5413" LastEditDate="2017-12-26T11:23:54.607" LastActivityDate="2017-12-26T11:23:54.607" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12963" PostTypeId="2" ParentId="12952" CreationDate="2017-12-26T13:27:34.373" Score="3" Body="&lt;p&gt;For processing large data it is a good practice to call data into RAM in slices(Either by spliting time axis or spatial domain). In the interest of earth sciences python packages &lt;strong&gt;Xarray&lt;/strong&gt;, &lt;strong&gt;iris&lt;/strong&gt;, &lt;strong&gt;netCDF4&lt;/strong&gt; and &lt;strong&gt;h5py&lt;/strong&gt; are few of the great tools for handling huge hierarchical data. For handling data in a labeled fashion Xarray and Iris will be useful while netCDf4 and h5py are good to process in a gridded way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My personal suggestion is &lt;strong&gt;h5py&lt;/strong&gt; which is meant for processing and archiving large datasets. Documentation &lt;a href=&quot;http://docs.h5py.org/en/latest/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; explains it. If you have netcdf files and want them in hdf5 format a &lt;a href=&quot;https://stackoverflow.com/questions/17332353/what-is-the-easiest-way-to-convert-netcdf-to-hdf5-on-windows&quot;&gt;question&lt;/a&gt; at Stack Overflow might help.&lt;/p&gt;&#xA;" OwnerUserId="11865" LastActivityDate="2017-12-26T13:27:34.373" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12964" PostTypeId="1" AcceptedAnswerId="12969" CreationDate="2017-12-26T17:21:47.973" Score="1" ViewCount="113" Body="&lt;p&gt;I was wondering if there was a name for the effect I’ve noticed over a lake in really cold weather.  You can see white wisps over it, which I think is mist from the lake rising into the air and condensing in the cold, sort of like breathing out in cold weather.&lt;/p&gt;&#xA;" OwnerUserId="7227" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T11:51:20.247" LastActivityDate="2019-08-29T11:51:20.247" Title="Is there a name for this weather phenomenon?" Tags="|meteorology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12969" PostTypeId="2" ParentId="12964" CreationDate="2017-12-27T03:38:51.960" Score="5" Body="&lt;p&gt;It is called frost smoke or steam fog (or a half dozen other names), sea smoke is the same effect just over the ocean. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is caused by  high moisture saturation and strong temperature differences between the water and the air. &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Steam_fog&quot; rel=&quot;noreferrer&quot;&gt;http://glossary.ametsoc.org/wiki/Steam_fog&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2017-12-27T03:38:51.960" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12970" PostTypeId="1" CreationDate="2017-12-27T05:01:42.723" Score="4" ViewCount="161" Body="&lt;p&gt;I'm reading about Sodom and Gomorrah on &lt;a href=&quot;https://en.wikipedia.org/wiki/Sodom_and_Gomorrah#Historicity&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; when I come across this:&#xA;&quot;One such idea is that the Dead Sea was devastated by an earthquake between 2100 and 1900 BCE. This might have unleashed showers of steaming tar.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is a &quot;tar shower?&quot;  Are there any documented cases of this?  When I googled this, it went to the visual dictionary referenced in the Wikipedia article, which didn't explain the concept either.&lt;/p&gt;&#xA;" OwnerUserId="11869" LastEditorUserId="94" LastEditDate="2017-12-27T16:56:29.493" LastActivityDate="2017-12-27T22:30:15.327" Title="What is a &quot;tar shower?&quot;" Tags="|meteorology|earthquakes|earth-history|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12971" PostTypeId="1" CreationDate="2017-12-27T07:39:09.817" Score="2" ViewCount="197" Body="&lt;p&gt;As far as i know earthquake is result of movement of earth crust layers and release of energy at these locations and movements at faults.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So i think its happens somehow along a line or in a wide almost flat layer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But each earthquake is given a coordination and a depth as if its like a spot explosion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is it like this? Are my assumptions wrong?&lt;/p&gt;&#xA;" OwnerUserId="11870" LastActivityDate="2017-12-31T18:06:00.357" Title="Why are earthquake considered spot things?" Tags="|earthquakes|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12972" PostTypeId="2" ParentId="12971" CreationDate="2017-12-27T10:58:19.903" Score="3" Body="&lt;p&gt;Faults and discontinuities within the Earth's crust are rarely smooth and any smooth parts are short in length.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The degree of roughness along a fault or any discontinuity varies in strength and magnitude. This causes stresses to build up unevenly along faults and discontinuities. When the stresses are too large for one rough patch to withstand there's a break and stress is released causing an earthquake. This is why earthquakes occur at a particular location.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2017-12-27T10:58:19.903" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="12973" PostTypeId="2" ParentId="12970" CreationDate="2017-12-27T20:08:00.507" Score="1" Body="&lt;p&gt;Natural oil seeps are not unusual, the light components evaporate leaving &quot;tar&quot;. Then an earthquake could cause a release of gas which if in just the right location could blow the tar into the air.  Normally the gas escapes through the tar and throws it only a very shot distance, like an inch.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastEditorUserId="6298" LastEditDate="2017-12-27T22:30:15.327" LastActivityDate="2017-12-27T22:30:15.327" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12975" PostTypeId="1" CreationDate="2017-12-28T17:05:05.073" Score="4" ViewCount="100" Body="&lt;p&gt;I'm attempting to water some crops on my small plot of land using water from a downhill creek. I want to pump the water uphill to a tank then use gravity fed drip irrigation. Sometimes ( usually after a rain ) the water gets quite cloudy. I was thinking of mounting the outlet of the tank in such a way that there is a later between the bottom and the outlet so that any particulate can settle out in the tank. Is there any way to determine the time that a certain sized particulate will take to precipitate out of water? In other words how long should I let the water settle before letting it drip&lt;/p&gt;&#xA;" OwnerUserId="11878" LastActivityDate="2017-12-28T17:05:05.073" Title="How can I figure out the time it will take different clay and silt particles to precipitate out of water" Tags="|precipitation|geologic-layers|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12976" PostTypeId="1" CreationDate="2017-12-28T19:44:51.330" Score="6" ViewCount="259" Body="&lt;p&gt;I've read that cold air moves faster than hot air, for example in an occluded front. But in case of anti-cyclone encountering a cyclone it appears that the cold air of the anti-cyclone moves very slowly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So why these differences and what causes this?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="94" LastEditDate="2018-01-27T08:26:34.370" LastActivityDate="2018-09-22T07:59:22.390" Title="Why is cold air fast in an occluded front, but slow in an anti-cyclone?" Tags="|meteorology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12977" PostTypeId="1" CreationDate="2017-12-28T22:55:44.793" Score="11" ViewCount="1047" Body="&lt;p&gt;The other day our low temperature for the day was ~10 degrees F below our forecast low.  I've noticed this before in the winter, especially when temperatures start to go below 0 degrees F (-18 degrees C).  This made me wonder if the models used to forecast high and low temperature are different, and if so is one indeed more accurate?  Conversely, if the same model is used, is it as accurate for both high and low temperatures? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was able to find &lt;a href=&quot;http://www.dartmouth.edu/~chance/course/student_projects/weather.html&quot; rel=&quot;noreferrer&quot;&gt;one student project&lt;/a&gt; from Dartmouth College in which a statistical analysis of forecast high and low temperatures were compared from three five years sets (1970-4, 1980-4, and 1990-4) of data from 15 different United States cities representing different influences such as latitude, water, and land influences.  One of the findings of this dataset of 5,269 records was that the forecasts where more accurate in the summer than in the fall and winter.  This seems to hint that warmer temperatures are forecasted more accurately than colder temperatures, at least on a seasonal basis.  I'm hoping there's more information out there that can either confirm or deny this conclusion without the seasonal bias.   &lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastEditorUserId="6298" LastEditDate="2018-05-05T22:40:24.980" LastActivityDate="2018-11-02T02:00:36.533" Title="Are weather forecast models more accurate for either high or low temperatures?" Tags="|meteorology|weather-forecasting|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="12978" PostTypeId="1" AcceptedAnswerId="13014" CreationDate="2017-12-29T02:11:38.237" Score="2" ViewCount="367" Body="&lt;p&gt;I’ve been doing research into mineral deposits in B.C. I’ve been overlaying old claims maps onto Google Earth maps. Are there any good public maps for metallic minerals for British Columbia online?&lt;/p&gt;&#xA;" OwnerUserId="11565" LastEditorUserId="28050" LastEditDate="2018-01-06T14:38:02.647" LastActivityDate="2018-01-06T14:38:02.647" Title="Geological maps of British Columbia" Tags="|geology|mineralogy|mapping|mining|resources|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12979" PostTypeId="2" ParentId="12978" CreationDate="2017-12-29T02:24:37.047" Score="2" Body="&lt;p&gt;Although not a geologic map this &lt;a href=&quot;https://opentextbc.ca/geography/chapter/5-3-british-columbias-natural-resources/&quot; rel=&quot;nofollow noreferrer&quot;&gt;site&lt;/a&gt; has a nice map of mines for silver, gold, copper, molybdenum, and zinc.  Below is a screenshot of just a portion of the pdf you can download.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pu3ny.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pu3ny.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2017-12-29T02:24:37.047" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12982" PostTypeId="1" AcceptedAnswerId="12989" CreationDate="2017-12-29T17:39:52.210" Score="0" ViewCount="171" Body="&lt;p&gt;Good day! On USGS web-site I can get co-called PGA/PGV (Peak Ground Acceleration/Velocity) values in the region of earthquake. It is possible to get the map of velocities with respect to time (to see how earthquake developed in time)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="11886" LastActivityDate="2018-01-03T15:18:14.620" Title="Earthquakes PGA/PGV in time?" Tags="|earthquakes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12984" PostTypeId="1" CreationDate="2017-12-30T03:22:52.243" Score="3" ViewCount="1078" Body="&lt;p&gt;Why does mineral oil occur below natural gas? It was asked in our science book in the Geology section and I didn't get a clear explanation from the teacher. &lt;/p&gt;&#xA;" OwnerUserId="11888" LastEditorUserId="28050" LastEditDate="2018-01-08T17:02:32.660" LastActivityDate="2018-01-10T21:45:50.300" Title="Why does mineral oil occur below natural gas?" Tags="|geology|fossils|fossil-fuel|" AnswerCount="5" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="12985" PostTypeId="2" ParentId="12984" CreationDate="2017-12-30T10:43:53.250" Score="1" Body="&lt;p&gt;it is all about the density.gass have a lower density than oil and oil have a lower density than water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;oil will float on water and gass will float on oil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;some gasses are lighter than air like hydrogen gass so this will float on air because hydrogen have lower density than air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;your question is about schoolwork so i asume this Q&amp;amp;A will be closed soon.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastActivityDate="2017-12-30T10:43:53.250" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12986" PostTypeId="2" ParentId="12757" CreationDate="2017-12-30T15:09:05.023" Score="2" Body="&lt;p&gt;Those blue colors are basically artefacts due to image processing. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.bing.com/maps?osid=7eb32f29-b56a-482e-9a7a-1c8ced25ae49&amp;amp;cp=17.483395~-2.649436&amp;amp;lvl=19&amp;amp;style=h&amp;amp;v=2&amp;amp;sV=2&amp;amp;form=S00027&quot; rel=&quot;nofollow noreferrer&quot;&gt;The last one in Bing Maps&lt;/a&gt; doesn't look blue at all. It's just somehow slightly darker with some trees or large animals. The local change of color might be caused by humidity (maybe a seasonal pond) or animals, or both - if animals come to drink. Interestingly, &lt;a href=&quot;https://www.bing.com/maps?osid=e43fd6c3-b085-4e7b-a25c-ed9f06f52739&amp;amp;cp=17.288925~-2.76744&amp;amp;lvl=19&amp;amp;style=h&amp;amp;v=2&amp;amp;sV=2&amp;amp;form=S00027&quot; rel=&quot;nofollow noreferrer&quot;&gt;there are similar shapes in the area&lt;/a&gt; and Bing Maps traces paths converging on them. I don't know how Bing gets those paths (I can't see them in the aerial imaging) but they are consistent with animal paths leading to ponds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And &lt;a href=&quot;https://www.bing.com/maps?osid=ca14bb17-3337-4528-8268-f4c72a193be6&amp;amp;cp=17.464976~-2.670773&amp;amp;lvl=17&amp;amp;style=h&amp;amp;v=2&amp;amp;sV=2&amp;amp;form=S00027&quot; rel=&quot;nofollow noreferrer&quot;&gt;the second one&lt;/a&gt; is just the bed of a dry lake, with salt pans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first one lacks coordinates, but we can assume it's just a another color enhanced rather normal piece of desert.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Edit&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;To actually answer the question &quot;I am wondering if this is some kind of satellite imagery to detect heat or moisture? Or is this the actual colour of rock/mineral?&quot;, as requested by comments:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer is &quot;No, it is neither the colour of rock/mineral or a heat or moisture detector. Blue color is just an artifact due to image processing, as can be seen from comparing those Google Maps images with linked Bing Map images of the same places, which aren't blue at all&quot;.&lt;/p&gt;&#xA;" OwnerUserId="6550" LastEditorUserId="6550" LastEditDate="2018-03-05T21:48:28.990" LastActivityDate="2018-03-05T21:48:28.990" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="12988" PostTypeId="2" ParentId="12984" CreationDate="2017-12-31T02:17:10.917" Score="3" Body="&lt;p&gt;&lt;a href=&quot;http://unitrove.com/engineering/tools/gas/liquefied-natural-gas-density&quot; rel=&quot;nofollow noreferrer&quot;&gt;Natural gas&lt;/a&gt; can occur above and below &lt;a href=&quot;http://www.thecalculatorsite.com/conversions/substances/oil.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;oil formations&lt;/a&gt; however when they occur in the same formation natural gas will sit on top because it’s density per kg/m3 is 800+ and natural gases density is 400+&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://unitrove.com/engineering/tools/gas/liquefied-natural-gas-density&quot; rel=&quot;nofollow noreferrer&quot;&gt;weight of natural gas&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.thecalculatorsite.com/conversions/substances/oil.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;weight of crude oil&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11565" LastActivityDate="2017-12-31T02:17:10.917" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12989" PostTypeId="2" ParentId="12982" CreationDate="2017-12-31T05:57:57.363" Score="0" Body="&lt;p&gt;No. However, you can look at backprojection results which show where the energy is coming from. It gives you some idea about how the earthquake evolved in time, e.g., see &lt;a href=&quot;http://ds.iris.edu/spud/backprojection/112354&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; (click play to see the video).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only other way to get what you want is to use observations from dense arrays. E.g., see &lt;a href=&quot;https://www.youtube.com/watch?v=1QCcVqZgNKw&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, but this is only possible in certain regions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT (answer to your comment below): Codes like SPECFEM3D are good for simulating low frequency ground motion (e.g., 0.1-1Hz). High frequency (1-10Hz) ground motion, that affects smaller structures like 1-2 story houses or even mid-rise buildings is very difficult to simulate (you need a very accurate, very high resolution, velocity model with the right soil/geotechnical layer etc., a highly accurate source model with the 'right' slip distribution, rise time, rupture velocity etc., and finally, a very large supercomputer). You're better off using GMPE's like USGS but that will not tell you how things evolve in time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bottomline is that statistics of high frequency ground motion are rather well understood (scales with distance) but not for lower frequencies where effects like rupture directivity/velocity, path/basin effect etc. become even more important.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, Okada's elastostatic solutions are for calculating the final displacement field and doesn't have time component, i.e., you can simulate the final slip but not how it evolves with time which is an elastodynamic problem. Also, the final displacement field alone doesn't tell you anything about PGA/PGV.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2018-01-03T15:18:14.620" LastActivityDate="2018-01-03T15:18:14.620" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12990" PostTypeId="1" CreationDate="2017-12-31T06:38:19.900" Score="3" ViewCount="121" Body="&lt;p&gt;The image below from the Australian &lt;a href=&quot;http://www.bom.gov.au/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bureau of Meteorology&lt;/a&gt; shows several thunderstorms in southeast Queensland today and the directions they are expected to move. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm surprised how different these directions are. I had imagined that &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the main influence on a storm's trajectory would be high level winds, and &lt;/li&gt;&#xA;&lt;li&gt;the high level winds would be relatively uniform in such an area, being unaffected by geographical features (hills, rivers).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;But that doesn't seem to fit with this evidence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What factors influence the direction of a storm's movement?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VEsd6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VEsd6.png&quot; alt=&quot;Thunderstorms in south-east Queensland&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11894" LastActivityDate="2017-12-31T06:38:19.900" Title="Why do nearby thunderstorms move in different directions?" Tags="|meteorology|atmosphere|wind|thunderstorm|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="12991" PostTypeId="2" ParentId="12971" CreationDate="2017-12-31T08:01:55.863" Score="2" Body="&lt;p&gt;The co-ordinates and depth refer to the modelled focus (or hypocentre) and the epicentre of an earthquake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You are correct in that faults can rupture along a plane, but the location and depth information given in an earthquake report is typically based on a point source model. The focus is assumed to be where the rupture begins, with seismic waves propagating outward from there, so the arrival of these waves can be used to calculate its location. The epicentre is directly above the focus on the ground surface and the focal depth is the distance between the two. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The USGS gives some background about the information they (and equivalent agencies in other countries) provide in earthquake reports here: &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/eventpage/terms.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earthquake.usgs.gov/earthquakes/eventpage/terms.php&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a diagram here, and in the link given by a previous commenter illustrating how the focus relates to the fault plane: &lt;a href=&quot;https://en.wikipedia.org/wiki/Hypocenter&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Hypocenter&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is some information from the USGS about modelling a point source location: &lt;a href=&quot;https://www.usgs.gov/faqs/how-do-seismologists-locate-earthquake?qt-news_science_products=7#qt-news_science_products&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.usgs.gov/faqs/how-do-seismologists-locate-earthquake?qt-news_science_products=7#qt-news_science_products&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6332" LastEditorUserId="6332" LastEditDate="2017-12-31T18:06:00.357" LastActivityDate="2017-12-31T18:06:00.357" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="12993" PostTypeId="2" ParentId="8211" CreationDate="2018-01-01T01:56:16.043" Score="2" Body="&lt;p&gt;We have just experienced rain from an almost cloudless sky in Forster Australia at 1230pm&#xA;Almost no wind at 4 knots. &#xA;Humidity very high&#xA;Lasted around 5 minutes with the rain drops increasing in size over the 5 minutes. &#xA;Nick&lt;img src=&quot;https://i.stack.imgur.com/BAOwP.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="11896" LastActivityDate="2018-01-01T01:56:16.043" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="12995" PostTypeId="2" ParentId="12984" CreationDate="2018-01-01T11:16:10.137" Score="0" Body="&lt;p&gt;The obvious answers have been posted, but I believe the question really should be why do they occur together? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer to such a question is because their source is the same - organic remains subjected to specific conditions: no oxygen, pressure, temperature, and a lot of time.&lt;/p&gt;&#xA;" OwnerUserId="109" LastActivityDate="2018-01-01T11:16:10.137" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="12998" PostTypeId="2" ParentId="12984" CreationDate="2018-01-02T02:49:27.207" Score="0" Body="&lt;p&gt;LOTS of time for density differences to cause migration miles through relatively solid rock. And beyond the level of the question to point out there is always water and often CO2 which make for some complicated ( for me) physical chemistry.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2018-01-02T02:49:27.207" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13000" PostTypeId="2" ParentId="12961" CreationDate="2018-01-02T06:49:09.383" Score="1" Body="&lt;p&gt;Why don't you think calcite is forming in-situ? The saturation index does not guarantee that calcite has precipitated (or dissolved) but there are a number of reasons to think it has. First, calcite does not have a large kinetic barrier to precipitation. The kinetics are fairly rapid. Rapid is a relative term but the formation of calcite in caliche and speleothems indicates that it does not take much for it to precipitate. Secondly, are you suggesting that it is merely coincidental that the SI indicates saturation? Do you have a number of water samples from different locations that are all in equilibrium with calcite? How would that occur without reacting to form or dissolve calcite? What else could be buffering the pH to the value at equilibrium between your solution and calcite?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Have you looked at the gypsum SI? Does it remain undersaturated? If so you would expect it to be dissolving which would move calcite towards supersaturation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One possibility is that you in equilibrium with both gypsum and calcite. In that case, they will fix the ion concentrations in solution and pH so you get no further precipitation (assuming the system is closed to carbon dioxide).&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2018-01-02T06:49:09.383" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13001" PostTypeId="2" ParentId="12955" CreationDate="2018-01-02T07:08:37.433" Score="1" Body="&lt;p&gt;Magnesium sulfate is considerably more soluble than calcium sulfate. What happens during evaporation will depend on the original ion concentrations but, for example with sea water, evaporation will cause gypsum to precipitate first. This will decrease the sulfate concentration until it is gone before magnesium sulfate will precipitate. The remaining calcium and magnesium will be charge-balanced by chloride and will increase in concentration past the point of halite precipitation. Only after further evaporation will magnesium and calcium chloride precipitate, but you won't get magnesium sulfate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get magnesium or sodium sulfate to precipitate you would have to have more sulfate in the system than calcium (on a meq basis) so that there is sulfate remaining after all the calcium is precipitated. Without any further details on the system they studied, it's hard to say if this is possible or not. Personally I would suspect that chlorides would be more likely.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2018-01-02T07:08:37.433" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13004" PostTypeId="1" CreationDate="2018-01-01T17:34:42.727" Score="7" ViewCount="219" Body="&lt;p&gt;Is there any kind of like an officially monitored list of falling asteroids, meteors, etc and objects entering earth's atmosphere?&lt;/p&gt;&#xA;" OwnerDisplayName="Lucian Marin" LastEditorUserId="507" LastEditDate="2018-04-29T16:07:26.283" LastActivityDate="2019-06-25T08:10:01.997" Title="Does a registry for fallen meteors exist?" Tags="|meteorite|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13005" PostTypeId="2" ParentId="12011" CreationDate="2018-01-02T17:45:17.223" Score="7" Body="&lt;p&gt;That mountain is mount Evans (3,950 m), located in the Sentinel Range in inner Antarctica (S 78.30698°, W 85.91698°), the highest mountain range in the continent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cZWNK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cZWNK.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Map courtesy of  @KeithMcClary see comments)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, geologic features become smoother by erosion (by water, glaciers or wind). These peaks are so high that there were never covered by glaciers and the area is so cold that liquid water almost doesn't exist. Therefore, there is no erosion by water (or freeze thaw cicles), neither the wind, because of the lack of dust/sand particles (the wind doesn't erode by itself, what do erode are the particle it carries). Consequently, those mountains are so sharp due to the lack of erosion.&#xA;Take for example any rock: If you break it into pieces, those pieces will have sharp edges, with no erosion those sharp edges will persist. Similarly, at a larger scale, sharp ridges and edges on mountains can persist and withstand the pass of time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ySiwh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ySiwh.jpg&quot; alt=&quot;This is me on mount Tyree camp one, during The Omega Foundation mapping expedition of 2005, mount Evans is in the background&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is me on mount Tyree camp one, during The Omega Foundation mapping expedition of 2005, mount Evans is in the background&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-04-13T02:38:47.513" LastActivityDate="2019-04-13T02:38:47.513" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="13006" PostTypeId="2" ParentId="12467" CreationDate="2018-01-02T18:05:07.680" Score="7" Body="&lt;p&gt;The easiest way is to look a the glacier margins. If the ice is in contact with vegetation or rock covered in lichens or moss, it means it is most likely advancing. If you see a band of life-less rock in between the ice and the first plants/lichens/moss, it means it is retreating.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some examples I've seen myself:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This glacier in Geenland is advancing, you can see the ice and vegetation in contact&#xA;&lt;a href=&quot;https://i.stack.imgur.com/JEF9Z.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JEF9Z.jpg&quot; alt=&quot;This glacier in Geenland is advancing, you can see the ice and vegetation in contact&quot;&gt;&lt;/a&gt;&#xA;Same glacier, you can see how it is even pushing vegetation, proving it is advancing&#xA;&lt;a href=&quot;https://i.stack.imgur.com/moF5Q.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/moF5Q.jpg&quot; alt=&quot;Same glacier, you can see how it is even pushing vegetation, proving it is advancing&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, advancing glaciers are the exception. In most cases they are reatreating and what you see is a band of life-less rock surrounding the ice like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Retreating Amalia glacier in Patagonia&#xA;&lt;a href=&quot;https://i.stack.imgur.com/5RZ0U.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5RZ0U.jpg&quot; alt=&quot;Retreating Amalia glacier in Patagonia&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The advancing or retreating state of a glacier can have different time-scales. For example a glacier can be retreating on a decade scale, but it might advance every winter, but the recession on summer is large enough to produce a net retreat every year. Small glaciers can also react very quick to weather variations, therefore even if one is receding at a century scale, it can advance one year due to exceptional snow accumulation over few years. So you have to interpret this observations with care, and consider what's the timescale at which the plants/moss/lichens can colonize the rock in the area, which in temperate and low elevations will be between a few years and a decade.&#xA;Moraines, trim lines and other features can tell you about the advancing/receding history of a glacier at longer timescales.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-02-12T18:56:44.970" LastActivityDate="2018-02-12T18:56:44.970" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13007" PostTypeId="2" ParentId="7083" CreationDate="2018-01-02T19:08:03.780" Score="1" Body="&lt;p&gt;It depends on your area of interest. If you are just testing a method, one of the large coverage free DEMs with high resolution (2m) is ArcticDEM, but as its name say it covers the Arctic only (Alaska, Northern Canada, Northern Europe, Russia, etc.). You can check that one out (&lt;a href=&quot;https://www.pgc.umn.edu/data/arcticdem/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ArcticDEM&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the coverage of ArcticDEM&#xA;&lt;a href=&quot;https://i.stack.imgur.com/H71C8.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/H71C8.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-01-11T17:46:35.390" LastActivityDate="2018-01-11T17:46:35.390" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13008" PostTypeId="1" AcceptedAnswerId="13009" CreationDate="2018-01-02T21:26:03.320" Score="1" ViewCount="60" Body="&lt;p&gt;We fish on several lakes on one property. Some lakes are frozen to 3 inches and others are ice free. If it has been below freezing for weeks, why haven't all lakes froze ?&lt;/p&gt;&#xA;" OwnerUserId="11910" LastActivityDate="2018-01-04T22:02:53.017" Title="Freeze variations" Tags="|hydrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13009" PostTypeId="2" ParentId="13008" CreationDate="2018-01-02T23:55:04.230" Score="2" Body="&lt;p&gt;Here are a few reasons from an Ask a Climatologist article on &lt;a href=&quot;https://www.alaskapublic.org/2017/11/01/ask-a-climatologist-why-do-some-lakes-freeze-faster-than-others/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Alaska Public Media&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Amount of water in the lake: It takes longer for a deeper lake to release all its heat, therefore it will take longer to freeze over.&lt;/li&gt;&#xA;&lt;li&gt;If the lake is surrounded by trees sunlight is less likely to reach&#xA;it during the winter.&lt;/li&gt;&#xA;&lt;li&gt;If there is water coming into a lake and leaving the lake from a coldwater stream the lake will freeze sooner because it will take longer for the lake to accumulate heat.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2018-01-02T23:55:04.230" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13013" PostTypeId="1" CreationDate="2018-01-03T09:40:30.587" Score="5" ViewCount="118" Body="&lt;p&gt;Last night, I was watching this programme on TV &lt;a href=&quot;http://www.bbc.co.uk/programmes/b09ksl99&quot; rel=&quot;noreferrer&quot;&gt;The Real T Rex&lt;/a&gt; where the presenter pointed out that smaller reptiles (crocodilians and mammals) &quot;somehow managed&quot; to survive the KT extinction event that wiped out the larger dinosaurs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The survival of the smaller animals wasn't a subject of the programme, so this wasn't explored further.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But this got me to thinking...  What environmental/climatic factors could have promoted the complete extinction of the larger air/land/sea animals but allowed smaller species to survive?&lt;/p&gt;&#xA;" OwnerDisplayName="user11784" LastEditorDisplayName="user11784" LastEditDate="2018-01-03T13:42:42.823" LastActivityDate="2018-01-03T23:04:43.487" Title="How were smaller reptiles/mammals more successful at surviving the KT event than larger dinosaurs?" Tags="|paleontology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13014" PostTypeId="2" ParentId="12978" CreationDate="2018-01-03T18:08:58.027" Score="2" Body="&lt;p&gt;The web site &quot;Map Place&quot; has a number of maps if you have internet explorer and can download an autodesk plugin.  &lt;a href=&quot;http://www.empr.gov.bc.ca/Mining/Geoscience/MapPlace/Pages/default.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;Table of Maps from Map Place&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have used this site to find locations with limestone bedrock but also to find old claims to look for areas with unique mineral samples.  I will caution you that the old claims in particular are not very accurately mapped.  A lot of the initial locations are based on hip chain and hand compass surveying, or even worst based on a location pointed out on a topographic map.  There has been little work to ground proof the old locations.  Some of the locations can be 500 meters or more out which doesn't seem like much, that is until you end up in dense forest looking over a 70 hectare area for an audit or cut.  Data collected since about 1994 and later started to be based on GPS ground measurements and are more accurate.  The majority of data now collect is based on tighter location data.  You may also find some issues with the datum used.  A lot of older data is based from NAD27, but the transition to NAD83 and WGS84 was over a time period and the data collected during the transition time wasn't always recorded with the datum information.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously the accuracy issue will depend on how you plan to used the data, it is likely ok for displaying zones of interest on a map.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2018-01-03T18:08:58.027" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13019" PostTypeId="2" ParentId="13013" CreationDate="2018-01-03T23:04:43.487" Score="3" Body="&lt;p&gt;It mostly has to do with three factors, numbers, fecundity, and behavior. Let's start with the last, certain behaviors that increase your chances of surviving are far more likely in smaller animals things like burrowing, and hibernation. They are also more likely to be generalists able to eat almost anything, specialization is a death sentence during a major environmental change. They also require less total amounts of food as individuals, it is far easier for a rat to find enough food to survive in a wasteland than an elephant, This is also true in comparing cold-blooded vs warm-blooded animals. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second you have numbers, there are several billion rats in NYC alone, even with the total destruction of the city it is very easy for a some rats to happen to be lucky enough to survive, small animals will die in larger numbers but there are so many of them they are more likely to have some survive. They literally have the law of large numbers in their favor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Last is reproduction, size is connected to reproduction, an elephant reproduces once every two years under ideal conditions, while a rat can breed every 24 days, so even if a few elephants do survive they repopulate so slowly they may never recover and some other minor event may finish them off. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if you combine these not only are small animals more likely to survive they can recover far faster than most large animals, so all things being equal you should expect small animals to be better at surviving and diversifying after a event. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2018-01-03T23:04:43.487" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13021" PostTypeId="2" ParentId="12927" CreationDate="2018-01-04T00:07:10.303" Score="-3" Body="&lt;p&gt;It depends on the height of the troposphere. On the equator troposphere has at least 12 km height, but in the polar latitudes it might be even less than 8 km. That difference in troposphere altitude allows clouds to form differently depending on the latitude. The second reason is that higher parts of the troposphere closer to the equator are warmer and contain more moisture than in the polar region. &lt;/p&gt;&#xA;" OwnerUserId="11875" LastEditorUserId="11875" LastEditDate="2018-02-03T09:29:12.137" LastActivityDate="2018-02-03T09:29:12.137" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13025" PostTypeId="1" CreationDate="2018-01-04T16:50:51.163" Score="7" ViewCount="925" Body="&lt;p&gt;&lt;em&gt;Disclaimer: this question is not about climate change or global warming in general, and does not try to dismiss general human-caused global warming.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The concept of runaway global warming depicts a scenario where the climate enters an unstoppable positive feedback loop, and this scenario is often depicted to happen before all fossil fuels have been used up. This topic often comes up in discussions about how long fossil fuels will last, with a warning that the planet would be uninhabitable if (or before) all fossil fuels were used up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, all these fossil fuels were once in the atmosphere in the form of CO&lt;sub&gt;2&lt;/sub&gt;, before they ended up absorbed by plants. Why didn't Venus-like conditions form back then, and since they didn't, why could the result be different in the future?&lt;/p&gt;&#xA;" OwnerUserId="2442" LastEditorUserId="6298" LastEditDate="2018-01-04T20:53:11.600" LastActivityDate="2018-02-12T23:19:16.833" Title="Why is runaway global warming a possibility despite all current fossil fuel deposits once having been in the atmosphere?" Tags="|climate-change|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13026" PostTypeId="2" ParentId="12960" CreationDate="2018-01-04T19:05:57.700" Score="1" Body="&lt;p&gt;&lt;strong&gt;We use $\rho V_\mathrm{P}$ because it agrees with experiment.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You point out that density and velocity are correlated and ask, &quot;why not use only velocity contrast or density contrast?&quot; instead of their product.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In truth, P-wave velocity $V_\mathrm{P}$ velocity is not necessarily &lt;em&gt;that&lt;/em&gt; well correlated with density $\rho$. Look at this plot of density vs $V_\mathrm{P}$ for rocks in a North Sea oil field from Avseth et al. (2001):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hAQ2N.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hAQ2N.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clearly, some of those rocks have almost no contrast on one axis, and can only be separated on the other. Indeed, this sums up the great problem of seismic inversion — we would like to recover these quantities individually, but all we can usually get at is impedance. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another example of the non-correlation of velocity and density is the so-called &quot;fizz effect&quot;: introducing a very small amount of gas in the pore-water, less than 5%, can reduce the P-wave velocity by as much as 20%, while having almost no effect on the density. The result: a substantial change in impedance (e.g. Han &amp;amp; Batzle 2002).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other thing about the product $\rho V_\mathrm{P}$ is that the impedance contrast at an interface gives us — quantitatively — the reflection coefficient $R$ at that interface (assuming vertical incidence; it's &lt;a href=&quot;https://agilescientific.com/blog/2011/6/6/what-is-avo.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;more complicated&lt;/a&gt; for other angles):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ R = \frac{Z_2 - Z_1}{Z_2 + Z_1} $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $Z_2$ and $Z_1$ are the acoustic impedances of the lower and upper layers respectively.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To go back to your more general question about intuition. I agree, the intuition is slippery. The analogy to electrical circuits seems obscure, and I daresay it does to other geologists. &quot;High impedance&quot; sounds to me like &quot;lots of opposition&quot;... so why is the velocity high in high impedance rocks? Perhaps because of this, I tend to focus on thinking of high impedance rocks as 'hard' and low impedance rocks as 'soft'. I find this more geologically useful. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I guess I don't have a very good answer for that part of your question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Avseth, P, T Mukerji, G Mavko, and JA Tyssekvam (2001). Rock physics and AVO analysis for lithofacies and pore fluid prediction in a North Sea oil field. SEG &lt;em&gt;The Leading Edge&lt;/em&gt;, April 2001, p 429–434. &lt;a href=&quot;https://library.seg.org/doi/abs/10.1190/1.1438968&quot; rel=&quot;nofollow noreferrer&quot;&gt;doi 10.1190/1.1438968&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;D-H Han and M Batzle (2002). Fizz water and low gas-saturated reservoirs. SEG The Leading Edge, 21(4), 395-398. &lt;a href=&quot;https://library.seg.org/doi/abs/10.1190/1.1471605&quot; rel=&quot;nofollow noreferrer&quot;&gt;doi 10.1190/1.1471605&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2018-01-04T19:05:57.700" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13027" PostTypeId="2" ParentId="12305" CreationDate="2018-01-04T19:50:21.587" Score="8" Body="&lt;p&gt;&lt;strong&gt;SEG-D is a specialized format, while SEG-Y is a general-purpose format.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, SEG-D is intended for field recordings of seismic data, and SEG-Y is intended for 'seismic data exchange'. Having said this, SEG-Y is so general-purpose, and so ubiquitous, that I'm not surprised to hear (anecdotally) that people are using it for data acquisition. Certainly, the recent release of Revision 2 — which allows for high sample rates, variable trace lengths, long records, and large files — facilitates this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an interpreter, I use SEG-Y all the time, whereas I've never come into contact with SEG-D. Thus, I don't know enough about it to go into any detail, but a quick look over the SEG-D specification suggests it has better support for describing receivers, channels, sources, and including things like observer logs. Which is what you'd expect in an acquisition format.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;SEG's formats are notoriously, er, flexible. So converting directly between the two formats may or may not be possible, depending on which fields have been used, and the lengths to which you're prepared to go to 'adapt' the target format to your use case. The usual way to convert, as it were, would be to process (i.e. demux, sort, image, and maybe stack) the field data in the SEG-D file(s), and write out one or more SEG-Y files.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Good luck!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://seg.org/Portals/0/SEG/News%20and%20Resources/Technical%20Standards/seg_d_rev3_1-oct2015.pdf&quot; rel=&quot;noreferrer&quot;&gt;SEG-D Rev 3.1 description&lt;/a&gt;, SEG Technical Standards Committee, 2015.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://seg.org/Portals/0/SEG/News%20and%20Resources/Technical%20Standards/seg_y_rev2_0-mar2017.pdf&quot; rel=&quot;noreferrer&quot;&gt;SEG-Y Rev 2.0 description&lt;/a&gt;, SEG Technical Standards Committee, 2017.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2018-01-04T19:50:21.587" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13028" PostTypeId="2" ParentId="6656" CreationDate="2018-01-04T21:32:07.790" Score="3" Body="&lt;p&gt;In Matlab if you have the mapping toolbox you can simply do:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;lon2=wrapTo180(lon2);&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;And your approach is totally right, but if you have to do it more often or with other dataset with diferent conventions you can set up functions analogous to those in the maping toolbox. Such as:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;function lon = wrapTo180(lon)&#xA;     q = (lon &amp;lt; -180) | (180 &amp;lt; lon);&#xA;     lon(q) = wrapTo360(lon(q) + 180) - 180;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;And&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;function lon = wrapTo360(lon)&#xA;    positiveInput = (lon &amp;gt; 0);&#xA;    lon = mod(lon, 360);&#xA;    lon((lon == 0) &amp;amp; positiveInput) = 360;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="81" LastEditDate="2022-04-11T22:46:13.393" LastActivityDate="2022-04-11T22:46:13.393" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="13030" PostTypeId="2" ParentId="13025" CreationDate="2018-01-05T00:19:26.463" Score="8" Body="&lt;p&gt;The largest reservoir of carbon is the rocks (sedimentary rocks) which reach into the order of the million gigatons (Gt). Over millions of years, part of that carbon have been released to the atmosphere by volcanoes. However, the amount of carbon in the atmosphere remains fairly stable because chemical erosion of rocks and plants capture that carbon excess and put it back in the geological reservoir.&#xA;There is about 4.700 Gt of fossil fuels, and the Atmosphere contain only 760 Gt of carbon.&#xA;So, if we burn all fossil fuels slowly, lets say over many millenia, there is not a problem, plants and erosion will keep the balance.&#xA;However, if we burn it quickly, let's say over few centuries, the greenhouse effect can be so strong that can kill many plant ecosystems and rise sea level, therefore reducing the surface area of rocks exposed to chemical weathering. Both effects would reduce the capacity of the system to restore the equilibrium, therefore it could take many millenia before all that carbon is returned to the geological reservoir so that temperatures can return to normal.&#xA;An extreme runaway case, like what happened in Venus, is unlikely to happen on Earth, but we don't really know. If temperatures ever reach to the point that oceans boil, then, there is a possibility that Earth might become like Venus forever.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/KGpoU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KGpoU.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-02-12T18:59:38.580" LastActivityDate="2018-02-12T18:59:38.580" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13031" PostTypeId="1" CreationDate="2018-01-05T00:36:08.007" Score="3" ViewCount="34" Body="&lt;p&gt;We are having a tough little northeaster in Boston, USA, right now and one oddity that I notice is the wind pattern. There will be complete calm for 3-5 minutes, then the wind will blow hard in gusts for 2-3 minutes and stop. Even stranger, the wind blows from a different direction each time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is the wind like this?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastEditorUserId="39" LastEditDate="2018-01-05T10:29:13.090" LastActivityDate="2018-01-05T10:29:13.090" Title="Why is wind sporadic in a Boston northeaster?" Tags="|meteorology|wind|storms|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13032" PostTypeId="1" AcceptedAnswerId="13035" CreationDate="2018-01-05T04:10:19.377" Score="4" ViewCount="2054" Body="&lt;p&gt;What is the split between night and day on Earth on average?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To further clarify, assume we are on the equator, I want to know how long a time, as a percentage, you could consider to be nighttime on Earth, with the points in time separating night and day being within sunrise and sunset.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried to answer for myself with many a time spent on Google, but I came up lacking so I am here to ask for help from you intelligent people that roam these parts of the internet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope this question fits in Earth Science, I couldn't think of a better place to ask.&lt;/p&gt;&#xA;" OwnerUserId="11926" LastActivityDate="2018-01-05T12:39:23.957" Title="How much of one day can be considered nighttime, on average?" Tags="|earth-rotation|sun|time|equator|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13033" PostTypeId="1" CreationDate="2018-01-05T10:23:21.643" Score="3" ViewCount="248" Body="&lt;p&gt;I have a bathymetry dataset that has a small section missing. I need to fill in this section.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The bathymetry in this region has some strongly directional features (e.g. a canyon that runs through the missing region). Using a standard interpolation function would weaken these features.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AELcz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AELcz.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there an appropriate method to estimate the missing values that gives more weight to known values along a given axis?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the moment the data is a GeoTIFF, and I'm using QGIS, but I can convert as necessary. I have straightforward access to MATLAB and R, as well as all the GRASS and SAGA tools included in QGIS.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2018-01-05T17:04:07.020" Title="Best way to interpolate bathymetry with a directional component?" Tags="|data-analysis|bathymetry|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13034" PostTypeId="1" AcceptedAnswerId="13036" CreationDate="2018-01-05T12:26:42.910" Score="8" ViewCount="11456" Body="&lt;p&gt;I don't know if this question's for here, physics, maths, or geometry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that this or something similar has been asked a million times, but I've recently come to the concept that since the horizon is a circle centered at the viewer's position, the whole horizon is at the same level, hence why it's flat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what is it that we're seeing when we start seeing the curvature once we're high enough? I have a feeling that the answer to this has to do with the angle that the globe takes in your &quot;camera&quot;, but the question still stands, what is this picture looking at? Why does it show a curve in the horizontal?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yPomB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yPomB.png&quot; alt=&quot;earth from low-earth-orbit&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11929" LastEditorUserId="28050" LastEditDate="2018-01-06T14:31:07.333" LastActivityDate="2024-01-14T13:55:33.797" Title="What are we seeing when we see the curvature of Earth?" Tags="|earth-observation|horizon|" AnswerCount="5" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13035" PostTypeId="2" ParentId="13032" CreationDate="2018-01-05T12:39:23.957" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;To further clarify, assume we are on the equator, I want to know how long a time, as a percentage, you could consider to be nighttime on Earth, with the points in time separating night and day being within sunrise and sunset.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I personally wouldn't consider that the dividing line between night and day. I consider night to be the period between dusk and dawn rather than sunset and sunrise. One doesn't need to stop playing a ball game on an unlit field just because the Sun has set. There's still another twenty to forty minutes of light from the blue sky. Dusk and dawn last the shortest in the tropics, with civil twilight (e.g., the period when one can continue playing a ball game on an unlit field) generally considered to be the 24 minute period prior to sunrise / after sunset in the tropics. With this, &quot;nighttime&quot; comprises about 47% of the time in the tropics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question however asks about the period between sunset and sunrise. Even on an airless planet, &quot;nighttime&quot; by this definition will comprise a bit less than half the time at the equator because sunrise and sunset occur when the top of the Sun appears above / drops below the horizon. Since the Sun's angular diameter is about 32 arc minutes, on average, this alone means that daytime is about two minutes longer than nighttime+twilight at the equator. We don't live on an airless planet. Atmospheric refraction means that when we see the very top of the Sun at the horizon, the Sun is geometrically well below the horizon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This, coupled with the Sun's angular size, makes daytime last about 12 hours and 6 to 8 minutes at the equator, with very little variation over the course of a year. Taking 12 hours and 7 minutes as the average, daytime represents 50.5% of the time while twilight plus nighttime (or just night, per the question) represents the other 49.5% of the time.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-01-05T12:39:23.957" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13036" PostTypeId="2" ParentId="13034" CreationDate="2018-01-05T12:40:28.463" Score="17" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;the horizon is a circle centered at the viewer's position&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There are two things wrong with this. The first is the assumption that the Earth is entirely spherical - there are no hills, mountains or other bulges to block the view. But let's make that assumption, because there's a more fundemental misunderstanding in the geometry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The horizon is a circle that is centered horizontally at your position, but not vertically, because by being above the surface you can see a little way around the curve of the planet. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you're standing on the ground you are only looking from a couple of metres altitude, so you can't see very far around - this means that the circle of the horizon is centered only a small distance below your feet. Note that from this height you can't make out any curvature in the horizon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you're standing at the altitude from which your picture was taken, the horizon circle is centered some depth into the planet. So you are not looking out across a circle, as you imagine - you are looking down, &lt;em&gt;onto&lt;/em&gt; a circle. Or if you like, you're looking down onto a disc that happens to have some portion of the planet piled on top of it. And when you look at a circle (or a disc) from above, it appears curved.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2018-01-05T12:40:28.463" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13038" PostTypeId="2" ParentId="12977" CreationDate="2018-01-05T15:42:18.567" Score="-3" Body="&lt;p&gt;The problem you may be seeing is due to how the weather industry calculates the low temperature for the day.  They use the period from 7pm of the current day to 7am of the following day.  Sounds completely ridiculous?  Me too, you can easily observe this for yourself.  Go to a site like intellicast and where it shows the 10-day weather forecast, it will also show the temperature as a graph line.  You can see that the forecast lows of the day are often wrong - it is the low for the next day.&lt;/p&gt;&#xA;" OwnerUserId="11931" LastActivityDate="2018-01-05T15:42:18.567" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13039" PostTypeId="2" ParentId="13033" CreationDate="2018-01-05T17:04:07.020" Score="2" Body="&lt;p&gt;I had the same problem with surface DEM's. The best solution I found in Matlab was using the scatteredInterpolant class, it is inbuilt in Matlab. It allows &lt;a href=&quot;https://en.wikipedia.org/wiki/Natural_neighbor_interpolation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Natural neighbour interpolation&lt;/a&gt; (that is a class of weighted distance interpolation as suggested in previous comments). The usage is like this:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;% IF X and Y are the coords of each grid cell (you can use meshgrid to get&#xA;% those)&#xA;invalidValue=NaN; % or -99999 or whatever is in your case&#xA;gapIdxs= DEM==invalidValue; %Indexes of the void cells&#xA;interpolant = scatteredInterpolant(X(~gapIdxs),Y(~gapIdxs),DEM(~gapIdxs),'natural');&#xA;% interpolant is now a function, and we can evaluate it at any point you&#xA;% want, in this case we evaluate it in the void cells&#xA;interpolatedValues=interpolant(X(gapIdxs),Y(gapIdxs));&#xA;% Now we patch the DEM&#xA;patchedDEM=DEM;&#xA;patchedDEM(gapIdxs)=interpolatedValues;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;That produce a result way better than cubic interpolation in my experience. If that is not enough, before you start doing manual picking of features you can explore &lt;a href=&quot;https://en.wikipedia.org/wiki/Kriging&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kriging interpolation&lt;/a&gt;.&#xA;Finally if you what to force directionality, you can rotate your data (using matlab imrotate) so that your main direction is vertical and then interpolate column by column (using matlab interp1).&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-01-05T17:04:07.020" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13040" PostTypeId="2" ParentId="13034" CreationDate="2018-01-05T17:41:55.303" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;the horizon is a circle centered at the viewer's position, the whole horizon is at the same level, hence why it's flat.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But it only looks flat as long as you are seeing that circle from within the same plane where the circle is. If you are in the plane of the circle, it becomes indistinguishable from a flat rectangle or any other shape.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, if you are a significant distance above that circle, you will start seeing it as an actual circle. Then when taking this to the full 3D picture, you start realizing that the Earth is round.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-01-05T17:41:55.303" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13041" PostTypeId="2" ParentId="12930" CreationDate="2018-01-05T21:19:20.250" Score="2" Body="&lt;p&gt;We actually expanded those two papers into a peer review paper located here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.hindawi.com/journals/amete/2017/1765428/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.hindawi.com/journals/amete/2017/1765428/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In it you can find our success of finding 2sd situations 70% of the time. Also, might I suggest looking at a website that has quite a few options like 500mb/surface map overlays along with verification situations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.stormhamster.com/bsr/bsr.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.stormhamster.com/bsr/bsr.php&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Joseph Renken&#xA;Lead Author&#xA;Twitter: @kopnfmradiowx&lt;/p&gt;&#xA;" OwnerUserId="11935" LastActivityDate="2018-01-05T21:19:20.250" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13042" PostTypeId="1" AcceptedAnswerId="16369" CreationDate="2018-01-06T05:57:05.670" Score="8" ViewCount="451" Body="&lt;p&gt;There are some unusual structures in recent images from the Mars &lt;a href=&quot;https://en.wikipedia.org/wiki/Curiosity_rover&quot; rel=&quot;noreferrer&quot;&gt;Curiosity Rover&lt;/a&gt;'s MAHLI (&lt;a href=&quot;https://en.wikipedia.org/wiki/Mars_Hand_Lens_Imager&quot; rel=&quot;noreferrer&quot;&gt;Mars Hand Lens Imager&lt;/a&gt;) shown in the Space.com article &lt;a href=&quot;https://www.space.com/39294-mars-rover-curiosity-weird-tube-structures.html&quot; rel=&quot;noreferrer&quot;&gt;Curiosity Rover Spots Weird Tube-Like Structures on Mars&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An astrobiologist (not at NASA) is quoted as saying that they looked &quot;...remarkably similar to Ordovician trace fossils...&quot; while others are quoted as suggesting that these are visually reminiscent of &lt;em&gt;bioturbation processes&lt;/em&gt; on Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What are Ordovician trace fossils and bioturbation, and what do they look like on Earth?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; NASA's Mars rover Curiosity captured this image on Jan. 2, 2018, with its Mars Hand Lens Imager (MAHLI). Using an onboard focusing process, the robot created this product by merging two to eight images previously taken by MAHLI, which is located on the turret at the end of the rover's robotic arm. Credit: NASA/JPL-Caltech/MSSS&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Cropped section are also included for better viewing, in the first one, sunlight can be seen below the structure near the bottom, showing that it extends somewhat upward from the rock below it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7TPMN.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7TPMN.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ek5Xk.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ek5Xk.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WidjR.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WidjR.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; Curiosity Mastcam right image taken on Dec. 15, 2017. Credit: NASA/JPL-Caltech/MSSS&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mCfcX.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mCfcX.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2018-01-07T00:49:49.303" LastActivityDate="2019-03-02T04:13:17.543" Title="What are Ordovican trace fossils, and what do they look like?" Tags="|planetary-science|fossils|mars|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13043" PostTypeId="2" ParentId="9017" CreationDate="2018-01-06T06:45:29.057" Score="0" Body="&lt;p&gt;While I have not seen any documentation of this, I would think that it is a virtual certainty that a hurricane can drop snow at sufficiently high altitudes. Perhaps the best example of such a place would be 18491ft Mount Orizaba on Mexico’s Gulf Coast close to Veracruz. I would venture to guess that, at this altitude, ANY hurricane probably results in severe blizzard conditions at the summit.&lt;/p&gt;&#xA;" OwnerUserId="11938" LastActivityDate="2018-01-06T06:45:29.057" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13044" PostTypeId="2" ParentId="13034" CreationDate="2018-01-06T10:01:13.433" Score="4" Body="&lt;p&gt;The horizon is a circle centered below the viewer's position. (Ignore for this question that the Earth is bumpy and not exactly spherical.) Imagine the lines of sight from your eye or camera to the points on the circle forming a cone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When viewing the horizon from near the surface the cone is very flat and the circle is edge-on and it is difficult to see that it is curved. The center of the circle, the base of the cone, is also near the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At high altitude the cone is &quot;more pointy&quot;. It is easier to see the curvature of the circle because it is no longer being seen edge-on. The center of the circle, the base of the cone, is below the surface of the earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As altitude increases the cone has a sharper point, the angle at the tip is smaller. This also means that more of the circle becomes visible in a given field of view which means more of the curvature is visible. Eventually, when the altitude is high enough the entire circle is visible in a given field of view looking down.&lt;/p&gt;&#xA;" OwnerUserId="11939" LastActivityDate="2018-01-06T10:01:13.433" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13045" PostTypeId="1" CreationDate="2018-01-06T12:07:41.370" Score="9" ViewCount="153" Body="&lt;p&gt;Are observations of Arctic sea ice in accord with what the IPCC forecasts says they should be? And as such is the ice reducing in an exponential or linear way?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For instance, from &lt;a href=&quot;https://www.scientificamerican.com/article/how-the-ipcc-underestimated-climate-change/&quot; rel=&quot;noreferrer&quot;&gt;https://www.scientificamerican.com/article/how-the-ipcc-underestimated-climate-change/&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Projection: The IPCC has always confidently projected that the Arctic&#xA;  ice sheet was safe at least until 2050 or well beyond 2100. Reality:&#xA;  Summer ice is thinning faster than every climate projection, and today&#xA;  scientists predict an ice-free Arctic in years, not decades.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And then is this prediction based on the curved line on the left (found &lt;a href=&quot;http://neven1.typepad.com/blog/2011/04/trends-in-arctic-sea-ice-volume.html&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;)&lt;br&gt;&#xA;or the straight one on the right (found &lt;a href=&quot;https://nsidc.org/arcticseaicenews/2017/01/low-sea-ice-extent-continues-in-both-poles/&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;)&lt;br&gt;&#xA;(both are from NSIDC data):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/W847O.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/W847O.png&quot; alt=&quot;icecomparison&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11238" LastEditorUserId="5594" LastEditDate="2018-01-09T08:05:30.233" LastActivityDate="2018-01-09T21:04:26.273" Title="Is the Arctic ice dissapearing faster than IPCC models say?" Tags="|climate-change|sea-ice|arctic|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13046" PostTypeId="2" ParentId="9857" CreationDate="2018-01-06T12:15:17.173" Score="-4" Body="&lt;p&gt;Hasn't anything to do with CO2. It's the atmospheric pressure. Venus receives very little sunlight but still very hot due to extreme pressure. Jupiter is extremely hot due the intense atmospheric pressure despite being much further from the sun. CO2 has very little effect trapping heat beyond 50ppm. The earth was in an ice age with 10 to 20 times the current CO2 levels&lt;/p&gt;&#xA;" OwnerUserId="11940" LastActivityDate="2018-01-06T12:15:17.173" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13048" PostTypeId="1" CreationDate="2018-01-06T21:02:29.197" Score="5" ViewCount="1109" Body="&lt;p&gt;Some rivers have been moving backwards. This got me thinking about an unusual idea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could there be terrain that causes two rivers, within a few miles of each other (10?), to flow in opposite directions? One flows east, the other flows west, passing each other by.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there anything like this on Earth already? Is it even possible?&lt;/p&gt;&#xA;" OwnerUserId="11944" LastEditorUserId="10681" LastEditDate="2018-02-27T11:10:44.817" LastActivityDate="2018-02-27T11:10:44.817" Title="Could parallel rivers flow in opposite directions?" Tags="|hydrology|rivers|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13051" PostTypeId="2" ParentId="13048" CreationDate="2018-01-07T09:05:00.153" Score="3" Body="&lt;p&gt;After about a minute of searching in what I thought was a likely place, here is an example from northern England.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/w8ffm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/w8ffm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All you need is two valleys draining in opposite directions, which is not really a particularly interesting or uncommon occurrence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note the grid squares are 1 km x 1 km so these are pretty close.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a bigger example I found from southern Greece. The two valleys are about 4 km apart in this example. The basic topographic setup is exactly the same as the previous example.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/G7Bko.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G7Bko.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2570" LastEditorUserId="2570" LastEditDate="2018-01-07T11:42:59.640" LastActivityDate="2018-01-07T11:42:59.640" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13052" PostTypeId="1" CreationDate="2018-01-07T12:15:32.643" Score="6" ViewCount="293" Body="&lt;p&gt;My understanding is that a dust devil is created when heated air rises rapidly displacing the cooler air above up. My question is, how relatively hot does the patch of air on the ground have to get in order to create a dust devil, and how is the heat related to the height and size? And secondarily, do dust devils tend to occur more frequently within a certain range ambient temperature?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://smd-prod.s3.amazonaws.com/science-red/s3fs-public/mnt/medialibrary/2005/07/10/14jul_dustdevils_resources/diagram2.gif&quot; alt=&quot;dust devil illustration&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="11948" LastActivityDate="2020-05-11T19:17:09.257" Title="What level of heat creates a dust devil?" Tags="|meteorology|air-currents|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13053" PostTypeId="1" CreationDate="2018-01-07T14:49:01.777" Score="4" ViewCount="68" Body="&lt;p&gt;Today's most likely outcome regarding climate change is between +3°C and +6°C. My guess is at least +5°C. Has anybody found some papers indicating the average increase at the equator and a prognosis about plant growth there? &lt;/p&gt;&#xA;" OwnerDisplayName="user11464" LastEditorUserId="28050" LastEditDate="2018-01-08T16:35:55.400" LastActivityDate="2018-01-08T16:35:55.400" Title="What will happen to the tropical rainforest when climate increases by 5°C?" Tags="|climate-change|climate|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13054" PostTypeId="1" CreationDate="2018-01-07T15:56:02.453" Score="8" ViewCount="2199" Body="&lt;p&gt;I recently moved into a new house with a 2 acre lake behind it. We’ve had 15 consecutive days below freezing, and the last 12 of those have been below 20 degrees (Fahrenheit)! Six days ago I shoveled off a small spot to test out whether it would be good to ice skate on the surface, with the plan that yesterday I would shovel off a much bigger area. Yesterday morning, however, I woke up to a big area straight across starting to melt! The temperature was about 5 degrees F. This morning it’s even larger. The temperature did not exceed 20 degrees yesterday. Though there has been frigid cold it has been sunny. Is it possible that the area I shoveled caused this? The rest of the lake looks exactly the same (About 2” of snow all over it. No signs of melting anywhere else.) I’ve attached before and after pictures. Can’t figure out how in the world this could happen. Any ideas? &lt;a href=&quot;https://i.stack.imgur.com/v9aTo.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/v9aTo.jpg&quot; alt=&quot;before picture&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ylEEH.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ylEEH.jpg&quot; alt=&quot;before picture&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11949" LastActivityDate="2018-06-03T13:56:31.363" Title="Why is my pond / lake melting when the temperature is still far below freezing?" Tags="|water|geothermal-heat|ice|lakes|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13055" PostTypeId="1" AcceptedAnswerId="13056" CreationDate="2018-01-07T16:21:55.660" Score="5" ViewCount="399" Body="&lt;p&gt;Absent human activity, what does cause forest fires? I mean aside from lightning strikes, which are usually accompanied by water in the form of rain, and very rare events like volcanic eruptions or meteor impacts?&lt;/p&gt;&#xA;" OwnerUserId="8457" LastActivityDate="2020-09-25T06:20:53.287" Title="With humans out of the equation, what could cause forest fire?" Tags="|human-influence|forest|fire|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13056" PostTypeId="2" ParentId="13055" CreationDate="2018-01-07T17:17:22.113" Score="6" Body="&lt;p&gt;Wildfires are mainly caused by humans (or their technology) and lightning. Lightning is the most prolific natural source.  There really aren't many other sources in most areas, unless there is volcanic activity or a meteor strike as you mention.  There are also occasional cases of wildfire when &lt;a href=&quot;http://www.bbc.com/news/science-environment-40877099&quot; rel=&quot;noreferrer&quot;&gt;peat dries out&lt;/a&gt;.&lt;br&gt;&#xA;During a hot-dry summer, it can take several days of rain to moisten vegetation enough so that the fire danger is curtailed.  If there is a little rain accompanied by lightning, it is probably much less than what is needed to lower the fire potential (dryness of vegetation).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, lightning strikes are not &quot;usually accompanied by rain&quot;.  In the Pacific Northwest, for example, there are several lightning-caused wildfires every summer in areas where summer rain is quite scarce.  This is discussed a little in &lt;a href=&quot;https://en.wikipedia.org/wiki/Lightning&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The term &lt;a href=&quot;https://en.wikipedia.org/wiki/Dry_thunderstorm&quot; rel=&quot;noreferrer&quot;&gt;dry lightning&lt;/a&gt; is used in Australia, Canada and the United States for lightning that occurs with no precipitation at the surface. This type of lightning is the most common natural cause of wildfires. Pyrocumulus clouds produce lightning for the same reason that it is produced by cumulonimbus clouds.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2018-01-07T22:25:49.373" LastActivityDate="2018-01-07T22:25:49.373" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13057" PostTypeId="2" ParentId="13048" CreationDate="2018-01-07T17:50:49.133" Score="7" Body="&lt;p&gt;One of my favorites: The Columbia and Kootenay rivers. The Kootenay River initially flows southeast, parallel to the initial northwest flow of the Columbia River. The Kootenay passes within 2 kilometers of Columbia Lake, the source of the Columbia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/X49i1.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/X49i1.png&quot; alt=&quot;Map showing the Kootenay and Columbia rivers&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sub&gt;Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Kootenay_River_Map.png&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/File:Kootenay_River_Map.png&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-01-07T17:50:49.133" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13058" PostTypeId="1" CreationDate="2018-01-07T23:06:28.657" Score="3" ViewCount="26" Body="&lt;p&gt;Aachtal, along with Lonetal, is a valley in the Swabian Jura, Germany, and the site of many famous archaeological sites of the upper Pleistocene. It also hosts a series of very large karst springs (Aachtopf, Urspingtopf, Blautopf). Have (some of) these springs been active in the upper Pleistocene?&lt;/p&gt;&#xA;" OwnerUserId="10751" LastEditorUserId="725" LastEditDate="2018-01-08T06:52:12.250" LastActivityDate="2018-01-08T06:52:12.250" Title="For how long have the great karst springs of the Aachtal been active?" Tags="|rivers|paleoclimatology|limestone|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13060" PostTypeId="2" ParentId="13054" CreationDate="2018-01-08T11:56:52.833" Score="3" Body="&lt;p&gt;My guess is that since ice (and the liquid water underneath it) is much better at absorbing thermal radiation than air, then even if the air temperature is below zero, the ice can heat up in the sun and melt a little bit. It will presumably then refreeze at night when there is no sun to keep it warm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This was probably also happening on the surface of the snow as well before you cleared it but you didn't notice it because there was no colour change.&lt;/p&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2018-01-08T11:56:52.833" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13061" PostTypeId="1" AcceptedAnswerId="13062" CreationDate="2018-01-08T14:30:53.390" Score="7" ViewCount="182" Body="&lt;p&gt;This might sound like a silly question to many of you, but I am addressing the comments of a referee regarding a study I'm trying to publish and I remained a little puzzled about this issue.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's assume I have set up a simplified model that processes biophysical and socioeconomic data to analyze an issue attaining water management. Biophysical data (mainly topographic, climatic, and hydrological) are available at relatively high resolution (0.25 or 0.5 degree), while socioeconomic data are available at country resolution. The model was set up to run at gridcell resolution (0.25 degree), but, of course, all the cells of the same country share the same values of the socio-economic variables. However the process is run for each individual cell and the results are different from cell to cell, even in the same country.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In my manuscript, I claim that the resolution of my study is a quarter degree. This sentence is contested by a referee that states: &quot;&lt;em&gt;The resolution of the results of a given study is actually defined by the coarsest dataset that the study uses (not the finest). Part of the data used are available only at country level, so the spatial resolution of their results is at that level, not finer&lt;/em&gt;.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, I understand that coarse biophysical data (precipitation, temperature, land use, ....) should be eventually downscaled to be used in a gridded modeling approach, but what about variables like &quot;&lt;em&gt;corruption&lt;/em&gt;&quot; or &quot;&lt;em&gt;quality of the institutions&lt;/em&gt;&quot;? Does a downscaling of such variables make any sort of sense? &#xA;What finally determines the spatial resolution of a study?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="8087" LastEditorUserId="28050" LastEditDate="2018-01-08T16:39:06.350" LastActivityDate="2018-01-08T17:00:05.687" Title="What determines the spatial resolution of a study?" Tags="|models|geospatial|grid-spacing|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13062" PostTypeId="2" ParentId="13061" CreationDate="2018-01-08T17:00:05.687" Score="4" Body="&lt;p&gt;&lt;strong&gt;It sounds to me like the reviewer is fixated on a 'rule' they encountered in grad school, but the rule ignores some real-world nuance (as rules do).&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quick caveat: my answer isn't definitive, it's more of an opinion, but it was too long for a comment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems intuitively true that some phenomena just &lt;em&gt;are&lt;/em&gt; smooth, so the resolution of the data is not the limiting factor in an analysis of resolution. I'm thinking of things like maps of average seasonal air temperature (say). Certainly, you can combine that with higher-resolution data and still claim to have a high-resolution analysis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other data may not be implicitly smooth, but it's interesting to aggregate the data for the purposes of generalization.So the quality of academic institutions obviously varies on a per-institution basis (or per teacher, if you want to get silly about it), but it would be crazy to interpolate data like that and, since it's reasonable to think there might be national-level influence (e.g. in funding for education), it only makes sense to aggregate it that way. Again, I think it's reasonable to argue that you can combine data like this with higher-resolution data and have a high-resolution analysis overall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Still other data may simply be oversmoothed, or smoothed on the wrong basis. Temperature data by country, or geological data on a 100-km grid... Then I'd say those are limiting the resolution of any analysis you do.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;In conclusion...&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;I can't think offhand of a way to formalize all this, and don't know of any research around it (though I'd bet on its existence). Assuming you don't want to go down the research rabbit hole, or have a protracted argument with the reviewer, my advice is to respond to the objection by using more specific language. Instead of generalizing, specify the resolutions of the various datasets involved and mention where it might be possible to improve the resolution.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2018-01-08T17:00:05.687" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13063" PostTypeId="1" CreationDate="2018-01-08T22:10:34.253" Score="3" ViewCount="90" Body="&lt;p&gt;With what programs can inclinometer data be processed? And how is instrumental correction done?&lt;/p&gt;&#xA;" OwnerUserId="11957" LastEditorUserId="28050" LastEditDate="2018-01-08T23:14:40.287" LastActivityDate="2018-01-08T23:14:40.287" Title="How is tiltmeter data processed?" Tags="|volcanology|measurements|data-analysis|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13064" PostTypeId="1" CreationDate="2018-01-09T13:37:49.083" Score="4" ViewCount="122" Body="&lt;p&gt;I'm trying to find info on the storminess of &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Baikal&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Baikal&lt;/a&gt;. I want to compare wave heights in a storm on this lake to wave heights in a storm on the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All I could find was very general information that Lake Baikal experiences a stormy season in autumn with approximately 18 stormy days per month. I could not find any hard statistical data on waves or winds.&lt;/p&gt;&#xA;" OwnerUserId="2733" LastActivityDate="2018-01-12T02:05:49.283" Title="How stormy (wave height) does Lake Baikal get?" Tags="|hydrology|storms|lakes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13065" PostTypeId="1" CreationDate="2018-01-09T18:00:13.403" Score="6" ViewCount="710" Body="&lt;p&gt;I am currently using a Pierson Moskowitz spectrum to model the wave energy in the Mediterranean Sea. However I don't think this this is appropriate due to the limited fetch in the coastal area that I'm interested in. Therefore I'm going to switch to a JONSWAP spectrum which will encorporate the fetch too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can't find many resources on how to go about calculating fetch except for the &lt;a href=&quot;https://cran.r-project.org/web/packages/fetchR/vignettes/introduction-to-fetchR.html&quot; rel=&quot;noreferrer&quot;&gt;fetchR&lt;/a&gt; package in R. I am not an R user (more Python/Matlab) although if this is the best option I will happily learn. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any other online resources for calculating fetch in the Med sea?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rachael &lt;/p&gt;&#xA;" OwnerUserId="7367" LastActivityDate="2018-01-09T18:00:13.403" Title="Calculating fetch" Tags="|ocean-models|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13066" PostTypeId="2" ParentId="13045" CreationDate="2018-01-09T21:04:26.273" Score="7" Body="&lt;p&gt;The &lt;a href=&quot;http://www.ipcc.ch/ipccreports/tar/wg2/index.php?idp=605&quot; rel=&quot;noreferrer&quot;&gt;IPCC said&lt;/a&gt; &quot;Although the Hadley Centre climate model underestimates sea-ice extent and thickness, the trends of the two models are similar. Both models predict continued decreases in sea-ice thickness and extent (Vinnikov et al., 1999), so that  by 2050, sea-ice extent is reduced to about 80% of area it covered at the mid-20th century.&quot; &#xA;The graph on &lt;a href=&quot;http://www.ipcc.ch/ipccreports/tar/wg2/index.php?idp=604&quot; rel=&quot;noreferrer&quot;&gt;this IPCC page&lt;/a&gt; shows a predicted decline in &lt;em&gt;annual average&lt;/em&gt; extent of about half a million km$^2$ from 2000 to now. Your monthly average graph shows a somewhat faster decline over this period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The SA article talks about the much more drastic decline in minimum (September) extent. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/XZXbx.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XZXbx.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;I can't find any IPCC prediction of minimums, so you could say the IPCC failed to predict it or you could say it's in accord with what the IPCC did predict about annual averages.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ice volume is also declining rapidly.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/zX82V.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zX82V.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2018-01-09T21:04:26.273" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13067" PostTypeId="2" ParentId="13054" CreationDate="2018-01-09T21:55:37.113" Score="0" Body="&lt;p&gt;The pond water may be in contact with the water table underground. Several feet underground, temperatures don't vary much from the average annual temperature. If the average annual temperature is sufficiently above freezing, liquid water from the water table could be feeding the pond. Also, rivers can flow in winter even when air temperatures are somewhat below freezing for the same reason, because they are fed by groundwater at temperatures above freezing.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2018-01-09T21:55:37.113" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13068" PostTypeId="2" ParentId="13034" CreationDate="2018-01-09T21:58:33.090" Score="1" Body="&lt;p&gt;An unobstructed horizon such as an ocean horizon dips below the horizontal due to Earth's curvature. The dip of the ocean horizon is noticeable from a height of 10 meters. So it is not necessary to be at high altitudes to notice Earth's curvature.&lt;/p&gt;&#xA;" OwnerUserId="8382" LastActivityDate="2018-01-09T21:58:33.090" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13069" PostTypeId="1" AcceptedAnswerId="13089" CreationDate="2018-01-10T15:39:30.363" Score="4" ViewCount="430" Body="&lt;p&gt;Is there an intuitive explanation for non-specialists why India is projected to experience a decrease in drought (= increase in &lt;a href=&quot;https://climatedataguide.ucar.edu/climate-data/palmer-drought-severity-index-pdsi&quot; rel=&quot;nofollow noreferrer&quot;&gt;PDSI&lt;/a&gt;) due to global warming, unlike most areas at the same latitude(s), at least according to &lt;a href=&quot;https://www2.ucar.edu/atmosnews/news/2904/climate-change-drought-may-threaten-much-globe-within-decades&quot; rel=&quot;nofollow noreferrer&quot;&gt;these maps by &#xA; Dai (2010)&lt;/a&gt;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LZqIz.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LZqIz.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11964" LastEditorUserId="11964" LastEditDate="2018-01-10T15:53:36.540" LastActivityDate="2018-01-12T02:23:22.567" Title="Effects of global warming on drought in India" Tags="|climate-change|drought|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13070" PostTypeId="1" AcceptedAnswerId="13074" CreationDate="2018-01-10T18:44:02.880" Score="5" ViewCount="392" Body="&lt;p&gt;How come the strike-slip 7.6 M earthquake, occurring January 9th, 2018, produced no tsunami? Has there ever been any produced in this region?&lt;/p&gt;&#xA;" OwnerUserId="11967" LastEditorUserId="2570" LastEditDate="2018-01-10T21:18:35.653" LastActivityDate="2018-02-12T01:30:39.587" Title="2018 Swan Islands earthquake tsunami" Tags="|earthquakes|seismology|tsunami|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13074" PostTypeId="2" ParentId="13070" CreationDate="2018-01-10T21:17:56.033" Score="8" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BFLHq.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BFLHq.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the centroid moment tensor published by the USGS as of 01/10/18 (it will likely be updated in the future). As you can see this was an almost pure strike-slip mechanism on a near vertical plane.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tsunamis are generated when the ocean floor is displaced upwards by an earthquake, displacing the water above it in the same pattern. This displaced water then spread out laterally to form the tsunami. Thrust faults tend to produce large seafloor uplifts and so most (maybe all?) tsunamis are associated with thrust faulting earthquakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There was no tsunami in this case because a strike slip fault like this does not produce a significant uplift of the seafloor. Instead the seafloor slides past each other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regard to the second part of the question; yes there have been tsunamis in the Caribbean before. &lt;a href=&quot;http://poseidon.uprm.edu/lander/tabla1a.htm&quot; rel=&quot;noreferrer&quot;&gt;This website&lt;/a&gt; provides a good list of known ones.&lt;/p&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2018-01-10T21:17:56.033" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13075" PostTypeId="2" ParentId="12984" CreationDate="2018-01-10T21:34:18.153" Score="2" Body="&lt;p&gt;I'm expanding upon a couple of the answers because none of them used the term &quot;buoyancy&quot; explicitly. Also, don't use the term &quot;mineral oil&quot;, just call it oil or petroleum. Mineral oil is a distillation by-product of petroleum and is not found in subsurface reservoirs.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's consider a simple example of a thick reservoir quality sandstone with constant lithology throughout the whole reservoir. Then there are two forces acting on fluids in the sandstone pore space in an undisturbed reservoir. The pore space is the space between the rock grains in the sandstone. By undisturbed, I mean a reservoir which has not been drilled. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The two forces are the buoyancy pressure and the capillary force. The buoyancy pressure is due to the difference of specific gravities between fluids in the pore space. The specific gravity is a unit-less proxy for density. More formally, the specific gravity is simply the ratio of the density of the substance to the density of water at 4 degrees Celsius. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The capillary pressure is due to fluids becoming trapped in narrow pore throats, and because of this pressure there is always an irreducible water saturation in the reservoir. Put simply, even in the gas or oil zone, water always occupies some fraction of the pore space. In other words, for most rocks water is sticky and oil is not. As a result, a bit of water is left behind even when the rock is full of oil or gas. This is the &quot; irreducible water saturation&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See these links:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://wiki.aapg.org/Buoyancy_forces_in_reservoir_fluids&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://wiki.aapg.org/Buoyancy_forces_in_reservoir_fluids&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://wiki.aapg.org/Buoyancy_pressure&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://wiki.aapg.org/Buoyancy_pressure&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once an exploration well has been drilled, figuring out the water and hydrocarbon saturations in the reservoir are &lt;em&gt;critically&lt;/em&gt; important because many subsequent decisions will be based upon these numbers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a reservoir containing gas, oil and water. The fluids will occupy the pore spaces of the formation from shallowest to deepest-- gas first, then oil and finally water.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a reservoir, one may have only gas or oil, but there is always water because water always exists as the major constituent of the pore space of underground formations unless it has been replaced by gas or oil. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition, due to the capillary pressure, the saturation of the reservoir fluids changes inside each gas/oil/water zone with depth and proximity to the nearest fluid contact. For example, near the oil-water contact, the water saturation is highest and decreases upwards to a constant minimum as it nears the gas-oil contact. Around that point, the oil saturation is at a maximum. The oil saturation then decreases from a maximum as the gas saturation increases, however, the water saturation is still a constant and minimum value.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More detail can be found here - &lt;a href=&quot;http://wiki.aapg.org/Fluid_contacts&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://wiki.aapg.org/Fluid_contacts&lt;/a&gt; .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm a geoscientist who works with petroleum engineers-- hope this helps!&lt;/p&gt;&#xA;" OwnerUserId="4926" LastEditorUserId="4926" LastEditDate="2018-01-10T21:45:50.300" LastActivityDate="2018-01-10T21:45:50.300" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13076" PostTypeId="1" CreationDate="2018-01-10T21:46:21.367" Score="1" ViewCount="113" Body="&lt;p&gt;Is there an equation that produces the amount of curvature of the Earth one should see at the altitude of &lt;code&gt;x&lt;/code&gt; (whatever &lt;code&gt;x&lt;/code&gt; may be)? I imagine it would be a complicated equation, and not as simple as people who believe the earth is flat say. (of course it isn't that simple, they always forget to include altitude)&lt;/p&gt;&#xA;" OwnerUserId="4864" LastEditorUserId="6298" LastEditDate="2018-01-10T21:56:06.783" LastActivityDate="2018-01-10T21:56:06.783" Title="How much curvature of the Earth can be seen at altitude?" Tags="|earth-observation|" AnswerCount="0" CommentCount="0" ClosedDate="2018-01-12T09:44:36.063" ContentLicense="CC BY-SA 3.0" />
  <row Id="13077" PostTypeId="1" CreationDate="2018-01-11T07:05:21.550" Score="5" ViewCount="103" Body="&lt;p&gt;Trace element atmospheric particles are introduced from different sources, with both anthropogenic and natural origins. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;By analyzing the concentration levels of 18 elements in samples of $PM_{2.5}$ and $PM_{10}$, the results showed that the size distributions of those elements are significantly different.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Rn2VN.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Rn2VN.png&quot; alt=&quot;trace particle breakdown&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A number of papers explained that difference in size fraction of various species is related to their different sources.    &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Natural origin: the crustal element (i.e., $Al$, $Ca$, $Mg$) are always accumulated in coarser particles.&#xA;  Anthropogenic origin: the anthropogenic emissions ($Cu$, $Zn$, $As$, $Pb$) are always accumulated in finer particles.   &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm wondering if the &lt;strong&gt;chemical property of different species&lt;/strong&gt; are important in determining their size distribution as well. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, is size distribution not solely related to emission source (natural abrasion =&gt; coarse particles; anthropogenic combustion =&gt; fine particles)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If so, what chemical properties would be essential to infer the tendency of the specific elements (into coarse particles or fine particle).    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any advice would be appreciated!  &lt;/p&gt;&#xA;&#xA;&lt;h2&gt;PS&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;In previous research, I have found out one factor might be important: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Volatity&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;The volatile elements (e.g., $As, Cd, Tl, Cu, Pb, Zn$) are strongly correlated across the size distribution and exist in the plume primarily as fine sulfate (0.6 mm diameter) with lesser amounts transported as coarse sulfates (3.5 mm diameter) and coarse chlorides (11 mm diameter).&quot; copied from $\text{Martin et al., JGR, 2012}$&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="28050" LastEditDate="2018-01-12T13:41:08.317" LastActivityDate="2018-01-12T13:41:08.317" Title="What controls the tendency of trace elements in different particle size fractions?" Tags="|geology|atmosphere|geochemistry|air-pollution|atmospheric-chemistry|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13078" PostTypeId="1" CreationDate="2018-01-11T07:10:17.957" Score="4" ViewCount="43" Body="&lt;p&gt;It would probably be a strange question for here but i will shoot it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to modify the shaders for Prepar3d the next version of MS flight simulator game.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have ways of interfering with ambient/diffuse ratios on objects terrain e.t.c Also you can control saturation of clouds sky terrain and objects. You can also use expressions and affect the above based on altitude,season,cloud coverage e.t.c&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What i am searching for is real life rules that i should apply to the above. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Examples:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Should i reduce saturation when the weather is full of clouds and light is not enough? What happens to the sky color as the altitude rises?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that the rules are infinite but i would appreciate some starting points that will help me adjust:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Terrain lighting and saturation based on season and cloud coverage&lt;/li&gt;&#xA;&lt;li&gt;Object reflection lighting and saturation based on season cloud&#xA;coverage and altitude&lt;/li&gt;&#xA;&lt;li&gt;Water lighting reflection and saturation based on cloud coverage.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I know that all the above depend on which part of the world you are in and many other factors. , so i need just an average for all in order to try to adjust the settings of the simulator close to a real world appearence.&lt;/p&gt;&#xA;" OwnerUserId="11969" LastActivityDate="2018-01-22T00:40:30.440" Title="What are the basic rules of how light and seasons affect landscape and objects lighting?" Tags="|meteorology|earth-system|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13079" PostTypeId="2" ParentId="13025" CreationDate="2018-01-11T08:09:22.307" Score="5" Body="&lt;p&gt;&quot;All fossil fuels&quot; is a grey area.   A lot of carbonate rock doesn't make good fuel.   There's also a lot of deep shale rock that might be considered fossil fuel that's unlikely to be used up because it's too hard to get to, though it can be fracked and a percentage of it could be used.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, the amount of fossil fuels required to be burned (and the rate of use), that might get to a runaway global warming is uncertain but could be enormous.   Perhaps orders of magnitude above our current projecte rate of consumption.  The Wikipedia article on &lt;a href=&quot;https://en.wikipedia.org/wiki/Runaway_greenhouse_effect#Distant_future&quot; rel=&quot;nofollow noreferrer&quot;&gt;Runaway Greenhouse&lt;/a&gt; says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;As the Sun becomes 10% brighter in about one billion years' time, the&#xA;  surface temperature of Earth will reach 47 °C (117 °F), causing the&#xA;  temperature of Earth to rise rapidly and its oceans to boil away until&#xA;  it becomes a greenhouse planet similar to Venus today.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The average surface temperature of the Earth is currently about 16° C, and was about 15° C 50 years ago.  Even the highest current IPCC projections are a far cry from the 47 degree estimate.   And while there's some uncertainty in these numbers, there's at least a pretty good chance that the runaway greenhouse transition point is out of our reach.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Why is runaway global warming a possibility &lt;strong&gt;despite all current&#xA;  fossil fuel deposits once having been in the atmosphere&lt;/strong&gt;?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The Earth used to have a lot more CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere hundreds of millions and billions of years ago, though there is some uncertainty as to how thick the atmosphere was, so good atmospheric models are impossible, but it's likely that CO&lt;sub&gt;2&lt;/sub&gt; levels were orders of magnitude higher a couple billion years ago than they are today, but that wasn't a too much heat problem because the Sun was smaller and less luminous.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cCKTj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cCKTj.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This chart gives an idea of how the transition happened, and, during Earth's past, the Earth was in fact, believed to &lt;a href=&quot;https://en.wikipedia.org/wiki/Snowball_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;have been a snowball&lt;/a&gt; for extended periods, even with higher CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/10B7P.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/10B7P.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also see &lt;a href=&quot;https://en.wikipedia.org/wiki/Faint_young_Sun_paradox&quot; rel=&quot;nofollow noreferrer&quot;&gt;Faint Young Sun Paradox&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are other factors.  Volcanic activity puts particulates and SO&lt;sub&gt;2&lt;/sub&gt; high in the atmosphere that reflects sunlight and cools the Earth and Earth was probably more volcanic hundreds of millions and billions of years ago.   Large meteor impacts like the Chicxulub impact &lt;a href=&quot;https://www.smithsonianmag.com/science-nature/what-happened-seconds-hours-weeks-after-dino-killing-asteroid-hit-earth-180960032/&quot; rel=&quot;nofollow noreferrer&quot;&gt;create flash warming&lt;/a&gt; followed by years of &lt;a href=&quot;http://www.latimes.com/science/la-sci-impact-winter-20140517-story.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;significant cooling&lt;/a&gt; caused by dust and ash blasted into the upper atmosphere.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There were, certainly, large enough meteors impacts during the late-heavy bombardment that the oceans boiled away and Earth was heated up and the atmosphere was hot and filled with water-vapor as well as CO&lt;sub&gt;2&lt;/sub&gt;, but those were fleeting periods in geological time.  The dust and debris blown into the atmosphere leads to fairly rapid cooling following those large impacts.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sun was too cold in the Earth's past for Earth to ever experience a runaway greenhouse effect, but in a billion years or so, &lt;a href=&quot;https://www.newscientist.com/article/mg14219191-900-science-fiery-future-for-planet-earth/&quot; rel=&quot;nofollow noreferrer&quot;&gt;that is expected to change&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="725" LastEditDate="2018-02-12T23:19:16.833" LastActivityDate="2018-02-12T23:19:16.833" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13081" PostTypeId="1" AcceptedAnswerId="13082" CreationDate="2018-01-11T09:49:30.120" Score="3" ViewCount="168" Body="&lt;p&gt;Is it a volcano in this image ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Aqgot.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Aqgot.png&quot; alt=&quot;this image&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The magnified version.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IOxgr.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IOxgr.png&quot; alt=&quot;magnified&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was browsing through earth images &lt;a href=&quot;https://epic.gsfc.nasa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; when I spotted this orange thing. Is it some oceanic volcano?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It may be an absurd question but is it a discovery?&lt;/p&gt;&#xA;" OwnerUserId="11971" LastEditorUserId="28050" LastEditDate="2018-01-12T13:48:28.350" LastActivityDate="2018-01-12T13:48:28.350" Title="Volcano in ocean?" Tags="|volcanology|geography|earth-observation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13082" PostTypeId="2" ParentId="13081" CreationDate="2018-01-11T12:14:16.447" Score="10" Body="&lt;p&gt;From a &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_submarine_volcanoes&quot; rel=&quot;noreferrer&quot;&gt;list &amp;amp; map of known seamounts and submarine volcanoes&lt;/a&gt; it is unlikely the orange region in your picture is a submarine volcano.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.mapsofworld.com/answers/world/how-deep-is-pacific-ocean/&quot; rel=&quot;noreferrer&quot;&gt;average depth of the Pacific Ocean&lt;/a&gt; is 4280 m. At such a depth, a submarine volcanic eruption would not produce such a large area of illumination.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is more likely that the orange region in your picture is &lt;a href=&quot;https://en.wikipedia.org/wiki/Sunglint&quot; rel=&quot;noreferrer&quot;&gt;sunglint&lt;/a&gt;, which is, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;a phenomenon that occurs when sunlight reflects off the surface of the ocean at the same angle that a satellite or other sensor is viewing the surface. In the affected area of the image, smooth ocean water becomes a silvery mirror, while rougher surface waters appear dark.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-01-11T12:14:16.447" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13084" PostTypeId="1" CreationDate="2018-01-11T16:18:46.357" Score="3" ViewCount="417" Body="&lt;p&gt;Good day! I have a problem replicating a result. Let us consider the top plot here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/hmJ3F.png&quot; alt=&quot;plots of seismograms&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the plot, velocity is in mm/s. I think the problem is to remove instrument response correctly. I downloaded seismogram and pole-zero instrument response. I want to obtain velocity data. The instrument response is already given in velocity. I was able to get synthetic seismograms as shown in the figure, but I have a problem working with real data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I need a signal to be filtered in 0.001–0.004 Hz&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using &lt;a href=&quot;http://ds.iris.edu/files/sac-manual/&quot; rel=&quot;nofollow noreferrer&quot;&gt;IRIS SAC&lt;/a&gt; software, I do:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;SAC&amp;gt; r KYK_BHZ&#xA;SAC&amp;gt; rmean&#xA;SAC&amp;gt; rtrend&#xA;SAC&amp;gt; taper&#xA;SAC&amp;gt; trans from polezero subtype KYK_LHZ.zp&#xA;SAC&amp;gt; bp p 2 n 4 c 0.001 0.004&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;I do not set &lt;code&gt;FREQlimits&lt;/code&gt; for transfer function at all here, but I tried to do it like &lt;code&gt;0.0009 0.001 0.004 0.005&lt;/code&gt; or &lt;code&gt;0.0009 0.001 1 2&lt;/code&gt;, but it also doesn't work.&lt;/li&gt;&#xA;&lt;li&gt;My synthetic seismogram is 1 Hz data, so I don't do any  resampling.&lt;/li&gt;&#xA;&lt;li&gt;I tried to do &lt;code&gt;trans from polezero subtype KYK_LHZ.zp to vel&lt;/code&gt;, but it also doesn't work.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sendspace.com/filegroup/f%2F2HM8t7IfS6Bm%2F4TDdn1A&quot; rel=&quot;nofollow noreferrer&quot;&gt;Both the data and zero-pole files are here.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;" OwnerUserId="11886" LastEditorUserId="28050" LastEditDate="2018-01-11T20:05:55.000" LastActivityDate="2018-01-16T12:30:25.803" Title="Seismogram deconvolution in SAC" Tags="|earthquakes|software|data-analysis|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13088" PostTypeId="2" ParentId="13064" CreationDate="2018-01-11T23:28:19.790" Score="2" Body="&lt;p&gt;An article &lt;a href=&quot;http://askbaikal.com/2012/01/how-huge-are-baikal-waves/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; says 4 meters. (No statistical data however, just a general information page)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Waves on Lake Baikal may reach a height of 4 meters. Sometimes they&#xA;  evaluated as 5 and even 6 meters, but it is most likely an estimation&#xA;  “by eye”, which has a large error. Height of 4 meters obtained by&#xA;  instrumental measurements on the high seas.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Another source, &lt;a href=&quot;https://books.google.com/books?id=bibY60NWOlEC&amp;amp;pg=PA179&amp;amp;dq=wave%20height%20lake%20baikal&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwjf9ZqmqdHYAhVF-mMKHWaQD14Q6AEILzAB#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Lakes Handbook: Lake Restoration and Rehabilitation&lt;/a&gt;&#xA;edited by Patrick O'Sullivan, C. S. Reynolds, (pg 179) agrees with this figure (emphasis mine):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Baikal exhibits many features of an ocean: abyssal depth, internal&#xA;  waves and seiches, tides, &lt;strong&gt;violent storms in which wave-height&#xA;  reaches up to 4m&lt;/strong&gt;, and deep water luminescence of uncertain nature.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6057" LastEditorUserId="6057" LastEditDate="2018-01-12T02:05:49.283" LastActivityDate="2018-01-12T02:05:49.283" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13089" PostTypeId="2" ParentId="13069" CreationDate="2018-01-12T02:23:22.567" Score="4" Body="&lt;p&gt;Since you asked for an intuitive explanation, my thoughts would be that due to predicted increasing sea and global temperatures, the models used might be predicting a corresponding increase in monsoonal moisture or duration. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_of_India#Tropical_wet&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate of India&lt;/a&gt; :&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In India a tropical wet and dry climate is more common. Noticeably&#xA;  drier than areas with a tropical monsoon climate, it prevails over&#xA;  most of inland peninsular India except for a semi arid rain shadow&#xA;  east of the Western Ghats.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;An article on &#xA; the &lt;a href=&quot;https://www.nationalgeographic.org/encyclopedia/monsoon/&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Geographic&lt;/a&gt; site discusses the relationship between the ocean air temperature and the monsoons in India:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The summer monsoon is associated with heavy rainfall. It usually&#xA;  happens between April and September. As winter ends, warm, moist air&#xA;  from the southwest Indian Ocean blows toward countries like India, Sri&#xA;  Lanka, Bangladesh, and Myanmar. The summer monsoon brings a humid&#xA;  climate and torrential rainfall to these areas.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So in a region which is warmer, both air and ocean temperature, this monsoon effect is apparently predicted to be altered accordingly, resulting in either a higher precipitation, or longer duration to the wet cycle, to effectively make this region &lt;em&gt;wetter&lt;/em&gt; than it is today. Without knowing more about how the models were derived, this is just speculation however.&lt;/p&gt;&#xA;" OwnerUserId="6057" LastActivityDate="2018-01-12T02:23:22.567" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13090" PostTypeId="2" ParentId="13077" CreationDate="2018-01-12T03:24:30.183" Score="2" Body="&lt;p&gt;Crustal elements are essentially from soil which have undergone compaction during geologic processes.  Particles are then lifted into the air (e.g. by wind) and coarse particles from the soil are suspended in the atmosphere.  If the particulate is from wildfire, it is still of &quot;natural origin&quot;, but the particulate is from a combustion source.  Combustion creates fine particles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anthropogenic particulate emissions are dominated by combustion sources, because so much of our industry and energy production uses combustible fuels.  Combustion creates fine particles.  However, there are still several anthropogenic sources that create coarse particulate (e.g. road dust, construction dust, agricultural processes, etc.).&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2018-01-12T03:24:30.183" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13091" PostTypeId="1" CreationDate="2018-01-12T10:33:06.613" Score="1" ViewCount="57" Body="&lt;p&gt;How much pyrite has to be oxidized to produce a sulfate concentration of 15 mM? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the solution initially has a pH of 8, roughly what would the pH drop to if there is no buffering of acidity? &lt;/p&gt;&#xA;" OwnerUserId="11471" LastEditorUserId="94" LastEditDate="2018-01-12T16:44:04.547" LastActivityDate="2018-01-12T16:44:04.547" Title="Pyrite oxidation" Tags="|geochemistry|minerals|homework|groundwater|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13092" PostTypeId="1" CreationDate="2018-01-12T11:07:37.153" Score="1" ViewCount="422" Body="&lt;p&gt;How to input climate data for AGNPS model? AGNPS model is developed USDA &lt;a href=&quot;https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/null/?cid=stelprdb1042468&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/null/?cid=stelprdb1042468&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11980" LastEditorUserId="11980" LastEditDate="2018-01-12T12:33:40.810" LastActivityDate="2018-01-14T10:48:57.343" Title="Agricultural non point source of pollution (AGNPS) model input data" Tags="|pollution|agriculture|watershed|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="13093" PostTypeId="1" CreationDate="2018-01-12T14:17:02.193" Score="4" ViewCount="20573" Body="&lt;p&gt;What are the differences between N-MORB, E-MORB and OIB with regards to:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Tectonic setting&lt;/li&gt;&#xA;&lt;li&gt;Geochemical features&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;There are several types of basalts, but I can't find a clearly explained article.&lt;/p&gt;&#xA;" OwnerUserId="11981" LastEditorUserId="5594" LastEditDate="2018-01-13T14:47:16.967" LastActivityDate="2018-01-13T14:47:16.967" Title="What is the difference between N-MORB, E-MORB and OIB?" Tags="|geochemistry|igneous|sea-floor-spreading|hotspot|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13094" PostTypeId="2" ParentId="13093" CreationDate="2018-01-12T20:47:33.147" Score="8" Body="&lt;p&gt;The nomenclature is confusing and recent studies have shown that among mid-ocean ridge basalts (generally called MORBs) that  normal mid-ocean ridge basalts (NMORB) should reflect the statistically usual composition while enhanced MORB (EMORB) and depleted MORB (DMORB) should reflect end-members of the MORB population.  &lt;a href=&quot;https://dash.harvard.edu/bitstream/handle/1/12363838/35260572.pdf&quot; rel=&quot;noreferrer&quot;&gt;Gale et. al 2013&lt;/a&gt; proposes the use of the term NMORB to refer to the most likely basalt composition encountered along the global ridge system distant from hotspots. The NMORB is given by the lognormal mean of the compositions of ridge segments more than 500 km away from plumes excluding back-arcs.  Contrary to some literature discussion,  NMORBs are NOT depleted in trace elements according to this Gale's work and so linkage between the idea of depletion and NMORBs should be broken. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gale et.al propose the term DMORB to recognize trace element depleted basalts. DMORBs would not be considered representative of the upper mantle or ocean crust nor would they be commonly found in ridge systems.  Finally, EMORB would refers to incompatible trace element enriched NMORBS via a statistical definition found in Gale et. al.  This statistical definition is due to the fact that current data does not allow clear spatial linkage of EMORBs to any particular form of ridge or plume system or island located near to both.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good example of an EMORB system is given by Iceland where the rate of magma production has caused volcanism to build the oceanic ridge above sea level.  In this environment, the predominant basalts are also tholeiitic basalts, but there are higher concentrations of incompatible trace elements. EMORBs are enriched in incompatible trace elements such as K, Ba, La, Rb compared to NMORBs.  By incompatible, one means elements that do not fit easily into the crystal structure of mineral elements in the mantle and are usually not found in upper mantle derived rocks because they are preferentially ejected into the melt. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;See this paper &lt;a href=&quot;https://dash.harvard.edu/bitstream/handle/1/12363838/35260572.pdf?sequence=1&quot; rel=&quot;noreferrer&quot;&gt;The mean composition of ocean ridge basalts - Gale - 2013&lt;/a&gt; for a detailed discussion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Generally, all MORBs are tholeiitic basalts occurring in oceanic spreading centers, such as an ocean ridge away from hot spots and back-arc basins. At these spreading centers, a relatively small range of chemical compositions of basalts are erupted to form the basaltic layer of the oceanic crust.  The main melting mechanism is likely decompression melting due to rising convection cells moving upward through the mantle beneath the ridges. The composition of these basalts typically ranges from olivine to quartz tholeiites. Tholeiitic magmas are sub-alkaline, meaning they contain less sodium and potassium than other basalts and can be distinguished from other basalts by the redox state of the magma from which they crystallized—- tholeiitic parent magmas are reduced whereas calc-alkaline parent magmas are oxidized.  All three NMORBS, DMORBS, and EMORBS share common chemical compositions (ordered by decreasing wt%) of SiO2, Al2O3, MgO, FeO, CaO.  They also share a common mineralogy of plagioclase, pyroxene and olivine. The plutonic equivalents to a tholeiitic basalt are diorite, gabbro, and anorthosite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the next section, &lt;a href=&quot;http://www.tulane.edu/~sanelson/eens212/basaltic&amp;amp;gabbroicrocks.htm&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt; is a great reference!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oceanic Island Basalts –basalts associated with islands in the ocean basins that generally occur away from plate boundaries, and are often associated with hot spots.  Most oceanic islands appear to be related to ascending plumes of hot mantle which operate independent of the main convection cells that ascend beneath ocean ridges and descend at subduction zones.  A wide variety of rocks occur in these islands, not all are basaltic, but all appear to be related to upper mantle melts.  One may find tholeiites, alkaline basalts, Hawaiites, trachytes and rhyolites in an OIB environment which span the compositional spectrum of magnesium, iron and the alkaline elements. From a melting perspective, low pressure environments tend to produce the tholeiitic magmas and high pressures are required to derive alkali basalts.  OIB mantle sources are enriched in incompatible elements and demonstrate a wider variety fractionization than MORBs. How does this occur?  a recent theory for OIB sources posits that subducted lithosphere sinks to the core/mantle boundary and mixes with the mantle to produce an enriched mantle which heats and rises in narrow plumes which channel this enriched mantle melt upward producing hotspots which produce the compositional variety of OIBs observed.&lt;/p&gt;&#xA;" OwnerUserId="4926" LastActivityDate="2018-01-12T20:47:33.147" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13095" PostTypeId="1" CreationDate="2018-01-13T01:21:12.050" Score="3" ViewCount="36" Body="&lt;p&gt;What are the kinetic barriers to dolomite precipitation? Does it precipitate out in solution as quickly as Calcite does? &lt;/p&gt;&#xA;" OwnerUserId="11471" LastActivityDate="2018-01-13T01:21:12.050" Title="Formation of dolomite" Tags="|geochemistry|mineralogy|biogeochemistry|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13097" PostTypeId="1" CreationDate="2018-01-13T04:33:56.303" Score="6" ViewCount="74" Body="&lt;p&gt;I have a layered aquifer with water that contains high concentrations of calcium and sulfate (~400 mg/L Ca&lt;sup&gt;2+&lt;/sup&gt;, ~1300 mg/L SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt;), at 50 cm below ground surface (bgs), 250 cm bgs and 300 cm bgs. The water level in the aquifer was quite low, due to evaporation and little recharge. I think gypsum formed in the surface and dissolved when it rained, carrying Ca&lt;sup&gt;2+&lt;/sup&gt; and SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt; downwards. I looked at Cl&lt;sup&gt;-&lt;/sup&gt; concentrations and they were really low, not even comparable to Ca&lt;sup&gt;2+&lt;/sup&gt; and SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt;, so how can I prove that evaporation was the mechanism that formed gypsum?    &lt;/p&gt;&#xA;" OwnerUserId="11554" LastEditorUserId="5594" LastEditDate="2018-01-13T14:46:48.593" LastActivityDate="2019-04-01T10:44:31.877" Title="Chloride and evaporation" Tags="|geochemistry|hydrology|mineralogy|groundwater|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13098" PostTypeId="2" ParentId="12636" CreationDate="2018-01-14T01:33:50.387" Score="3" Body="&lt;p&gt;Kriging IS gridless. In fact Kriging and RBF are formally equivalent. The reason kriging tends to used on grids is more historical in the oil industry than anything else. The original papers in geostats made no mention of grids. They became popular in the oil industry because a) Flow simulation is generally done on a grid  b) upscaling is non linear (so the linear kriging change of support that was developed for mining was not applicable)..and modelling on a fine grid with flow based upscaling became the norm. c) People were more interested in simulations than estimations...and upscaling becomes even more important in this case&lt;/p&gt;&#xA;" OwnerUserId="11986" LastActivityDate="2018-01-14T01:33:50.387" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13099" PostTypeId="2" ParentId="13092" CreationDate="2018-01-14T10:48:57.343" Score="1" Body="&lt;h1&gt;tldr;&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;On the official support page titled &lt;a href=&quot;https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/national/water/manage/hydrology/?cid=stelprdb1043611&quot; rel=&quot;nofollow noreferrer&quot;&gt;AGNPS Climate Data -- agGEM &amp;amp; preGEM&lt;/a&gt; you find a download link to a &lt;a href=&quot;http://www.wcc.nrcs.usda.gov/ftpref/wntsc/H&amp;amp;H/GEM/AGNPSclimFileTemplate.txt&quot; rel=&quot;nofollow noreferrer&quot;&gt;climate data template file&lt;/a&gt;. Your data files need to have this format. All meteorological variables are written into this file. The template file contains daily data. It is not clear if either the data has to have daily resolution or the data can be finer (hourly) or coarser (monthly) resolved.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;detailed answer&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Everything I write down below is described on one the official support pages for AGPNS: &lt;a href=&quot;https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/national/water/manage/hydrology/?cid=stelprdb1043611&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://go.usa.gov/KL0&lt;/a&gt; (This is the &lt;strong&gt;official&lt;/strong&gt; short link provided by the United States Department of Agriculture (USDA))&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Remarks&lt;/h3&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The meteorological input data files for AGNPS model (&lt;strong&gt;Ag&lt;/strong&gt;ricultural &lt;strong&gt;n&lt;/strong&gt;on-&lt;strong&gt;p&lt;/strong&gt;oint &lt;strong&gt;S&lt;/strong&gt;ource Pollution Model) are actually called &lt;em&gt;climate input data&lt;/em&gt;, although the files contain short term meteorological data.&lt;/li&gt;&#xA;&lt;li&gt;All the provided programs are Windows executables.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;h3&gt;generate climate input data files for known locations&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Use the program &lt;em&gt;agGEM&lt;/em&gt;. This program uses an existing &lt;em&gt;statistical parameter file&lt;/em&gt; (maybe: == climatological data?) of meteorological data to generate a climate input data file for AGNPS. There are 233 stations in the US, for which such statistical parameter files exist. There is no information on the support page whether the data are measurement or model data. The program can be downloaded without registration from the support page linked above. The existing statistical parameter files can be also downloaded on that page. &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;generate your own statistical parameter file&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;The USDA provides a program called preGEM to generated statistical parameter files. preGEM needs an input data file with a long time series of meteorological data. What &lt;em&gt;long&lt;/em&gt; means is to decide by the use.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The format of this particular input data file is not clear. According to the &lt;a href=&quot;http://www.wcc.nrcs.usda.gov/ftpref/wntsc/H&amp;amp;H/GEM/agGEMpreGEMdocumentation.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;agGEM &amp;amp; preGEM documentation file&lt;/a&gt; one can choose between two types of text files: csv and &lt;em&gt;fixed format&lt;/em&gt; (see the manual what the latter means) during the execution of preGEMs. However, a &lt;a href=&quot;http://www.wcc.nrcs.usda.gov/ftpref/wntsc/H&amp;amp;H/GEM/preGEM_input_template.xls&quot; rel=&quot;nofollow noreferrer&quot;&gt;preGEM input template&lt;/a&gt; is provided on the support page, which is a xls file. Maybe one can also choose xls as format for the input data file.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please be aware that there are a lot of options when you save a xls as csv via the spreadsheet software of your choice: delimiters for strings, delimiter between columns (comma, tab, semicolon, ...) etc.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Build your own climate input data file&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;There is a &lt;a href=&quot;http://www.wcc.nrcs.usda.gov/ftpref/wntsc/H&amp;amp;H/GEM/AGNPSclimFileTemplate.txt&quot; rel=&quot;nofollow noreferrer&quot;&gt;climate input data template&lt;/a&gt; provided on the given support page. You can generate your own file without using arGEM and preGEM. There is a file header which nicely describes how the file has to be structured. The file looks as follows:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;*************************************************&#xA;*** a few words of explanation:&#xA;*** The Climate input data for AGNPS has the following fixed format.&#xA;*** The first line is required and must contain the current version ID&#xA;*** The second line may contain any info the user wishes.&#xA;***&#xA;*** The third line contains site latitude, longitude, elevation, &#xA;*** temperature lapse rate with elevation, &#xA;*** percentage N in the precip, and unit code.&#xA;*** The temperature lapse rate units are degrees F per foot or degrees C&#xA;*** per meter of elevation and can be left at zero.&#xA;*** The nitrogen percentage in the precip is currently not used in the&#xA;*** program, but units are percentage by weight.&#xA;*** The unit code is 1 for English and 0 for metric.&#xA;***&#xA;*** The fourth line contains the start date for the data.&#xA;*** The fifth line contains the end date for the data.&#xA;***&#xA;*** The sixth through eighth lines contain data column headings&#xA;*** &#xA;******* climate file starts below this line:&#xA;Climate File Input Version ID:          5.00&#xA;   56  Princeville       &#xA;   22.0708  159.1234    345.00   -0.0036    0.0000         1&#xA;01/01/0001&#xA;12/31/0100&#xA;     Daily   -Air Temperature-   Precip-     Dew        Sky      ----- Wind -----   Solar     Storm    Potent-&#xA;    Date     Maximum   Minimum   itation     Point     Cover     Speed  Direction Radiation  Type ID    ial ET&#xA;mm/dd/yyyy     [ºF]      [ºF]      [in]      [ºF]       [%]      [mph]       [º] [BTU/h/ft^2]    [-]      [in]&#xA;01/01/0001     73.08     67.10      0.00     59.46      75.4      3.67               87.30&#xA;01/02/0001     77.12     60.72      0.08     61.19      39.2      5.61              123.27&#xA;01/03/0001     78.22     58.41      0.28     60.80      80.9      3.85               79.23&#xA;01/04/0001     79.22     60.80      0.24     60.81      34.7      2.43              127.03&#xA;01/05/0001     80.62     69.15      1.84     67.06      79.8      6.96               79.44&#xA;01/06/0001     82.05     66.88      0.25     64.65      30.0      4.29              128.66&#xA;01/07/0001     80.89     62.94      0.07     60.28      52.7      3.59              114.29&#xA;01/08/0001     77.59     63.79      0.00     60.51      33.0      4.14              129.61&#xA;01/09/0001     75.78     61.29      0.00     57.00      53.0      3.69              115.94&#xA;01/10/0001     74.65     57.61      0.11     54.61      46.9      4.04              122.56&#xA;01/11/0001     78.17     60.47      0.52     61.41      38.5      5.44              126.81&#xA;01/12/0001     74.93     64.24      1.18     62.55      67.1      5.47               99.94&#xA;01/13/0001     74.97     62.35      0.63     66.70      84.6      3.82               73.72&#xA;******* This line and below are not in the input file.&#xA;*** In this template the data ends on 01/13/0001, but the actual file&#xA;*** must obviously continue to 12/31/0100 because of the specified&#xA;*** end date on line 5.&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2018-01-14T10:48:57.343" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13100" PostTypeId="1" AcceptedAnswerId="13104" CreationDate="2018-01-14T15:17:42.193" Score="5" ViewCount="162" Body="&lt;p&gt;For my study, I need to use satellite Sea Surface Temperature (SST) and at the same time I also need satellite air temperature data (Ta) for the first few meters above the ocean.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For SST I'll be using data obtained from infra-red measurements collected by several satellite radiometers and statistical interpolation.(&lt;a href=&quot;https://podaac.jpl.nasa.gov/dataset/OISST_UHR_NRT-GOS-L4-BLK-v2.0?ids=Measurement&amp;amp;values=Ocean%20Temperature&amp;amp;search=%22Black%20Sea%22&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://podaac.jpl.nasa.gov/dataset/OISST_UHR_NRT-GOS-L4-BLK-v2.0?ids=Measurement&amp;amp;values=Ocean%20Temperature&amp;amp;search=%22Black%20Sea%22&lt;/a&gt;) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far, I understand that remote sensing of Ta can only be estimated using several methods. My question is: Are there satellite data or products regarding the Ta above the ocean that I can use in my study?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope I was clear, thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="11987" LastEditorUserId="11987" LastEditDate="2018-01-14T15:53:26.353" LastActivityDate="2018-01-15T06:32:57.557" Title="Satellite ocean near-surface air temperature data" Tags="|meteorology|oceanography|temperature|remote-sensing|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13101" PostTypeId="2" ParentId="7885" CreationDate="2018-01-14T18:37:47.793" Score="16" Body="&lt;p&gt;&lt;strong&gt;The sand IS the original dirt, or at least what's left of it.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Sand is one of the major constituents of soil. Soils are roughly half minerals by volume and those minerals are silt, sand, and clay. In fact sand is often the largest single constituent of most common soils. Silt and clay are smaller and lighter, and can be moved by wind much easier when dry, this leads to the removal of everything but the heavier sand particles in very dry conditions.   What has happened is that without water and life to bind the material together, wind has removed all the lighter particles leaving nothing but sand and pebbles. Wind is good at sorting grains by size so each area tends to only have one grains size.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Where it came from originally&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;. Sand is just weathered rock, if you look at a map of the sahara there are quite a few scattered mountains and highlands in the desert. That is where the sand (and the original silt and clay) came from originally, weathering of rock, and the sahara is mostly exposed rock, with sand only making up a minority of its surface.&lt;/p&gt;&#xA;&lt;p&gt;I suggest the wiki for getting started on soil science, if you are interested, &lt;a href=&quot;https://en.wikipedia.org/wiki/Soil&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Soil&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;More on what sand is, &lt;a href=&quot;http://www.sandatlas.org/sand/&quot; rel=&quot;noreferrer&quot;&gt;http://www.sandatlas.org/sand/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;More on wind driven sorting, &lt;a href=&quot;https://people.ucsc.edu/%7Ejzachos/migrated/eart120/lectures_08/LECT7B.pdf&quot; rel=&quot;noreferrer&quot;&gt;https://people.ucsc.edu/~jzachos/migrated/eart120/lectures_08/LECT7B.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-01-15T07:46:31.650" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13102" PostTypeId="2" ParentId="7885" CreationDate="2018-01-14T21:32:53.677" Score="4" Body="&lt;p&gt;Only 25% of the Sahara is sand and dunes. 70% of the Sahara is bare rock and stones. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Un-watermarked version avaliable on www.alamy.com&#xA;&lt;a href=&quot;https://i.stack.imgur.com/EfIlB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EfIlB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Silicon makes up 27 percent of rocks on average. The Sahara is covered 25 percent by SiO2. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Algeria and Morocco are 800m average, &#xA;Chad and Egypt are about 500m, &#xA;Lybia and Mauritania are about 270m&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sand and rock material was there all the time, it's just been changed and collected into dune zones. The quartz is stronger and lighter and it sorts itself to the top, and the dark mafic minerals are sorted by gravity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Sahara has had aridity troubles for the last 30 million years, the alps are only 35 million years old. They say it was all green, perhaps like India, Nevada and California and Texas. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's probably changed from desert to savanna many times in the last millions of years due to ice ages. Perhaps there was a kind of biannual monsoon during ice ages, and the monsoon transitions to the current rain habit every time for the past 35 million years, which is when the alps started forming. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The north african shield has zones hundreds of millions of years old, I cant find pages on the geology of N Africa, it is volcanically active: &lt;a href=&quot;https://www.volcanodiscovery.com/north-africa.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.volcanodiscovery.com/north-africa.html&lt;/a&gt; The massive Atakor volcanic field is the largest in the Hoggar (or Ahaggar) volcanic province of southern Algeria and covers an area of 2150 sq km&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2018-02-08T14:44:47.420" LastActivityDate="2018-02-08T14:44:47.420" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13103" PostTypeId="1" CreationDate="2018-01-15T02:47:37.417" Score="4" ViewCount="59" Body="&lt;p&gt;I want to build a small atmospheric sensor setup that will include an anemometer. It doesn't have to be especially accurate but should be small, lightweight and reliable. The part I'm missing is the wind cups and its interface to the Pi, I've got the directional stuff figured. Any leads on where I might shop?&lt;/p&gt;&#xA;" OwnerUserId="11994" LastEditorUserId="12057" LastEditDate="2018-02-09T01:57:12.633" LastActivityDate="2018-02-09T01:57:12.633" Title="Want to buy wind speed sensor, small, cheap" Tags="|meteorology|wind|" AnswerCount="0" CommentCount="3" ClosedDate="2018-02-09T12:01:41.177" ContentLicense="CC BY-SA 3.0" />
  <row Id="13104" PostTypeId="2" ParentId="13100" CreationDate="2018-01-15T06:32:57.557" Score="2" Body="&lt;p&gt;This is not a definitive answer but a few points from someone who has spent some time with remotely sensed temperature data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I guess your best bet to get high spatial and temporal resolution surface air temperature would be to get reanalysis data from weather models and augment it with weather data from ships.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Purely satellite retrievals of surface air temperature are not very reliable as this is a rather indirect measurement. Consider Level 2 AIRS 50 km (approx. 0.5 deg) Surface Air Temperature data layer (&lt;a href=&quot;https://disc.gsfc.nasa.gov/datasets/AIRS2RET_V006/summary?keywords=airs%20version%206&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://disc.gsfc.nasa.gov/datasets/AIRS2RET_V006/summary?keywords=airs%20version%206&lt;/a&gt;). The spatial resolution is much lower compared to surface radiative temperature products. This is in order to compensate for the uncertainty in the atmospheric state and for lower resolution of the sensor that needs to balance its very high spectral resolution with lower spatial resolution to achieve usable SNR levels in each spectral channel.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Speaking of the reanalysis data the NCEP Global Data Assimilation System has 1 deg (approx. 100 km) spatial resolution. However depending on the region of study you might get higher resolution from regional weather models provided by local meteorologists. So you could start with the NCEP data spatially interpolated from 1 deg to 0.01 deg as an initial approximation.&lt;/p&gt;&#xA;" OwnerUserId="2511" LastActivityDate="2018-01-15T06:32:57.557" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13105" PostTypeId="1" AcceptedAnswerId="13118" CreationDate="2018-01-15T09:21:18.587" Score="4" ViewCount="266" Body="&lt;p&gt;&lt;a href=&quot;http://www.globalcitymap.com/oceania/images/oceania-physical-map.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;This map&lt;/a&gt; shows an island a bit east of the Marianas. I took a screenshot of the relavent part.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xj1KE.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xj1KE.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hunted around for it in Google Earth with no luck, but I did find a promising candidate here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0bysT.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0bysT.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I could not get any sort of label to appear, but the terrain data from Google Earth says that thing has a minimum depth of -42 meters. It's about 600 km east of the Marianas. You can see the coordinates at the bottom of the picture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone know what it's proper name is?&lt;/p&gt;&#xA;" OwnerUserId="2733" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T21:11:29.320" LastActivityDate="2019-08-28T21:11:29.320" Title="What is this island or reef 600 km east of Marianas Islands?" Tags="|geology|oceanography|sea-floor|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13106" PostTypeId="2" ParentId="13105" CreationDate="2018-01-15T11:39:41.570" Score="2" Body="&lt;p&gt;According to the &lt;a href=&quot;https://earthref.org/SC/#top&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seamount Catalog&lt;/a&gt; that particular seamount is unnamed.&#xA;From the co-ordinates you gave (16.12 N, 152 E) the nearest seamount is Del Cano Seamount with co-ords of 16 N, 148 23' E, which is about 3.5 degrees of longitude to the west of the seamount you are asking about.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-01-15T11:39:41.570" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13107" PostTypeId="1" CreationDate="2018-01-15T15:37:52.240" Score="1" ViewCount="497" Body="&lt;p&gt;Please can anyone explain how to calculate apparent heating (Q1) and apparent moisture sink (Q2) as defined by Yanai et al. (1972) using NetCDF data? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please kindly check equation 6(Q1) and 7(Q2) of the paper via this link (&lt;a href=&quot;http://journals.ametsoc.org/doi/abs/10.1175/1520-0469(1973)030%3C0611:DOBPOT%3E2.0.CO;2&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://journals.ametsoc.org/doi/abs/10.1175/1520-0469(1973)030%3C0611:DOBPOT%3E2.0.CO;2&lt;/a&gt;). I would like to use variables in the left hand side of the equations to solve for the Q1 and Q2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would prefer to get the explanation in NCL or any other language.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks.  &lt;/p&gt;&#xA;" OwnerUserId="11996" LastActivityDate="2022-06-16T10:47:21.240" Title="Calculation of apparent heating (Q1) and apparent moisture sink (Q2) as defined by Yanai et al. (1972) using NetCDF data?" Tags="|meteorology|mesoscale-meteorology|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13108" PostTypeId="1" CreationDate="2018-01-15T16:21:12.213" Score="2" ViewCount="66" Body="&lt;p&gt;We live in a house overlooking a salt water river. We overlook a cove. The river feeds into Narragansett Bay in Rhode Island. In the 17 years we have lived here, the river has frozen several times. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In early January of this year there were record breaking low temps which were below zero in our area. The river froze solid for a couple weeks. A couple of days ago we had record breaking WARM temps with steady rainfall. The morning after the rain storm we noticed that the bottom of the river was exposed but no water flow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is alarming to me because we've never seen anything like this to this extent where it has stayed without the river flowing into the cove for several days. I searched the web and found this site. Hoping someone can come up with an answer! Thank you.&lt;/p&gt;&#xA;" OwnerUserId="11997" LastEditorUserId="5594" LastEditDate="2018-01-15T17:01:27.813" LastActivityDate="2018-01-16T13:40:34.417" Title="Saltwater River Freeze and Thaw" Tags="|oceanography|" AnswerCount="1" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="13109" PostTypeId="2" ParentId="13084" CreationDate="2018-01-15T16:25:47.717" Score="2" Body="&lt;p&gt;I typed in the commands as shown using your data in SAC. I've uploaded my result.  The plot window shows the result of the commands run in the highlighted red area. Is this what you are trying to do? The plot xlim is set from 1750 s to 2700 s.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dhQdv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dhQdv.png&quot; alt=&quot;analysis in SAC&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4926" LastEditorUserId="28050" LastEditDate="2018-01-16T12:30:25.803" LastActivityDate="2018-01-16T12:30:25.803" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13111" PostTypeId="1" AcceptedAnswerId="13117" CreationDate="2018-01-15T22:12:34.677" Score="5" ViewCount="324" Body="&lt;p&gt;&lt;strong&gt;The problem&lt;/strong&gt;:  There are lots of websites that provide snow forecasts for various ski resorts.  The area of interest to me is Japan, specifically the Nagano area, where I use snow-forecast.com and www.windyty.com to get fairly accurate snow forecasts at elevation for the resorts I'm interested in, and in the case of Windy, also for other mountain peaks outside of the ski resorts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, unsurprisingly, often in the morning it turns out that the forecasts are not always perfect.  In fact, they can often be way off.  Sometimes a big storm never materializes, and sometimes it affects only certain areas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Japanese Meteorological Agency (JMA) has public hourly weather station data, but the weather stations tend to be down in towns, rather than on mountain peaks, and are not necessarily near the ski resorts in question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My solution at the moment is to frequently check the radar during storms, watching hour by hour to see which areas are being affected by the storm, correlate it with the weather station data, and try to make a prediction about which resorts are getting the most snow.  Needless to say, this is fairly time consuming and often misses some things (if the storm is a surprise, if there is a big storm somewhere that I'm not checking).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;My proposed solution:&lt;/strong&gt;  Write a script to screen scrape the radar images from the JMA and watch the pixel values of the areas in question, considering the pixel values to be a function of mm precip/hour, and taking the integral of the pixel function over time to get a &lt;em&gt;rough estimate&lt;/em&gt; of total mm precip over the past 24 hours.  I can probably then use other data at the weather stations to fit a function to calculate estimated snowfall from mm precip, elevation, and temperature.  It obviously will be pretty inaccurate, but at least it should be able to tell me with a decent degree of certainty whether there is no snow, a little bit, a lot, or tons, which is the only degree of accuracy I need.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Questions about my proposal&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Is it more or less a sound idea?&lt;/li&gt;&#xA;&lt;li&gt;Does this data (&quot;snow accumulation in the past 12-24 hours at an arbitrary lat/lon position&quot;) already exist somewhere that I don't know about?&lt;/li&gt;&#xA;&lt;li&gt;Is there more accurate source of radar data somewhere?  I'm currently screen scraping the JMA website to download the images, then sampling the image pixel values to get the mm precip at a given position, but the data has already been discretized, presumably for aesthetic reasons.  I would way rather just pay someone for access to a web service that will take the lat/lon and a timestamp and spit out a more accurate number.&lt;/li&gt;&#xA;&lt;li&gt;Is there an easier way to do this that I'm missing?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;JMA website where I get the data:  &lt;a href=&quot;https://www.jma.go.jp/en/highresorad/&quot; rel=&quot;noreferrer&quot;&gt;https://www.jma.go.jp/en/highresorad/&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Sample radar image:  &lt;a href=&quot;https://www.jma.go.jp/en/highresorad/highresorad_tile/HRKSNC/201801111000/201801111045/zoom6/34_28.png&quot; rel=&quot;noreferrer&quot;&gt;https://www.jma.go.jp/en/highresorad/highresorad_tile/HRKSNC/201801111000/201801111045/zoom6/34_28.png&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Sample weather station page:  &lt;a href=&quot;http://www.jma.go.jp/en/amedas_h/today-48141.html?areaCode=000&amp;amp;groupCode=33&quot; rel=&quot;noreferrer&quot;&gt;http://www.jma.go.jp/en/amedas_h/today-48141.html?areaCode=000&amp;amp;groupCode=33&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="11982" LastActivityDate="2018-01-17T20:00:29.087" Title="Can I use radar data to estimate snowfall, or is there a better way?" Tags="|meteorology|snow|radar|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13112" PostTypeId="1" CreationDate="2018-01-16T00:19:09.167" Score="1" ViewCount="65" Body="&lt;p&gt;In 2014, &lt;a href=&quot;https://www.epa.gov/ghgemissions/global-greenhouse-gas-emissions-data&quot; rel=&quot;nofollow noreferrer&quot;&gt;the world emitted 10 billion metric tonnes of carbon dioxide&lt;/a&gt;. A &lt;a href=&quot;http://www.nytimes.com/2012/12/04/science/how-many-pounds-of-carbon-dioxide-does-our-forest-absorb.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;50 year old oak tree forest sequesters 30,000 pounds of CO2 per acre&lt;/a&gt;. At that rate of sequestration per acre, offsetting all carbon emissions would require &lt;a href=&quot;https://www.wolframalpha.com/input/?i=(10*10%5E9%20metric%20tons)%20%2F%2030000%20pounds%20per%20acre&quot; rel=&quot;nofollow noreferrer&quot;&gt;735 million new acres of trees&lt;/a&gt;, which sounds like a lot but is only &lt;a href=&quot;https://www.wolframalpha.com/input/?i=735%20million%20acres%20%2F%20((Land%20area%20of%20earth))&quot; rel=&quot;nofollow noreferrer&quot;&gt;about 2% of the world's total land area&lt;/a&gt;. By comparison, Europe is about 1490 million acres, and the United States is 2400 million acres.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would it be practical / possible to offset global carbon emissions by reforesting 2-3% of the earth's land area, specifically in deforested regions? I know you can't just conjure up a 50 year old oak forest, but by choosing the right species of trees it should be possible. &lt;/p&gt;&#xA;" OwnerUserId="11998" LastActivityDate="2018-01-16T00:19:09.167" Title="Could we plant enough trees to offset greenhouse gas emissions?" Tags="|climate-change|carbon-cycle|greenhouse-gases|" AnswerCount="0" CommentCount="1" ClosedDate="2018-01-16T09:13:45.553" ContentLicense="CC BY-SA 3.0" />
  <row Id="13115" PostTypeId="2" ParentId="13108" CreationDate="2018-01-16T13:40:34.417" Score="1" Body="&lt;p&gt;I suspect that rather than an ice jam as suggested in the comments, that this was a consequence of sustained high winds that happened to be blowing in just the right direction, thereby blowing the waters away from the side of the bay to which the inlet / bayou / saltwater river is connected.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Negative storm surge can drain shallow bays, sometimes dropping sea level by several feet. This happened, for example, along the west coast of Florida prior to Hurricane Irma. (That negative storm surge became a positive storm surge when the winds shifted direction.) This happens with great regularity where I live. The bayous later today and tomorrow will be very, very low due to a cold front that is pushing through right now.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-01-16T13:40:34.417" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13117" PostTypeId="2" ParentId="13111" CreationDate="2018-01-16T15:58:42.060" Score="3" Body="&lt;p&gt;Full disclosure: Being in Florida, I don't spend as much time watching winter weather, and don't have great experience correlating radar precipitation totals to actual snowfall.  Is it spring yet?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I do at least some background and information, and so hopefully can add some insight.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using radar is certain to have imperfections...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Smaller Radar Caveats:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Radar beams increase in height with distance from the radar.  They really don't tell you what is actually happening at the ground, but instead up at &lt;a href=&quot;http://www.storm2k.org/phpbb2/viewtopic.php?t=87311&quot; rel=&quot;nofollow noreferrer&quot;&gt;some height aloft&lt;/a&gt;... this may mean that, especially further from the dish, light precipitation shown on radar can actually be &lt;a href=&quot;http://www.iweathernet.com/educational/what-is-virga-theres-rain-on-radar-but-its-dry-outside&quot; rel=&quot;nofollow noreferrer&quot;&gt;evaporating before hitting the ground&lt;/a&gt;... or you may not get any precipitation showing up at all because sometimes convection can be so shallow that it is only below the radar beam and thus undetected (&lt;a href=&quot;http://journals.ametsoc.org/na101/home/literatum/publisher/ams/journals/content/bams/2017/15200477-98.2/bams-d-15-00034.1/20171013/images/large/bams-d-15-00034.1-f2.jpeg&quot; rel=&quot;nofollow noreferrer&quot;&gt;example&lt;/a&gt; &lt;sup&gt;&lt;sub&gt;[2.5 km ≈ 8200 ft])&lt;/sub&gt;&lt;/sup&gt;)&lt;/li&gt;&#xA;&lt;li&gt;Radar beams are also blocked by elevated terrain, such that some areas in mountainous regions may not return any data.  &lt;a href=&quot;https://www.roc.noaa.gov/WSR88D/Maps.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;See for example this map&lt;/a&gt; of the regions that are visible to US weather radars, and note the jagged/non-circular shapes common in the west indicative of mountains.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The exact radar setup is very important in determining the utility of the data.  In addition to the range and terrain issues, the beam angle and width alter what returns mean, some frequencies &lt;a href=&quot;https://en.wikipedia.org/wiki/Weather_radar#Attenuation&quot; rel=&quot;nofollow noreferrer&quot;&gt;attenuate&lt;/a&gt; or reflect certain drop/flake sizes better than others, etc... so exact radar details are very crucial.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was able to dig up &lt;a href=&quot;https://translate.google.com/translate?sl=auto&amp;amp;tl=en&amp;amp;js=y&amp;amp;prev=_t&amp;amp;hl=en&amp;amp;ie=UTF-8&amp;amp;u=http%3A%2F%2Fwww.river.go.jp%2Fx%2Fxmn0107010.php&amp;amp;edit-text=&amp;amp;act=url&quot; rel=&quot;nofollow noreferrer&quot;&gt;this site&lt;/a&gt; that shows the range outlines of nine Japanese radars and then &lt;a href=&quot;http://www.jma.go.jp/jma/en/Activities/radar/radar.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;the full JMA radar specs page&lt;/a&gt;.  Looks like probably the radar spacing is pretty quality generally, but the frequencies are quite different than the radars &lt;a href=&quot;https://www.roc.noaa.gov/WSR88D/Engineering/NEXRADTechInfo.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;I'm used to&lt;/a&gt;.  In the end, understanding the nuances and return characteristics of a radar's setup can be a very intensive life-long process for even the best of meteorologist! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Greater Complications of Estimating Snow&lt;/strong&gt;  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Also note that winter precipitation adds an extra complication because the particles are lighter in weight and can thus be blown about more by vertical and horizontal winds.  Raindrops (and hail) are quite likely to fall unless extreme updrafts exist because they are heavy.  But drizzle, snow, and sleet may be blown around quite a bit.  Without a time-intensive dual-Doppler analysis, you cannot know the wind motion in the storm thoroughly, and therefore will have varying results at times.&lt;/li&gt;&#xA;&lt;li&gt;And finally, the big wrench is unfortunate inherent to how radars work.  They measure the percentage of their sent energy that is reflected back to them.  That's great because that's directly connected to the diameter of the item falling (to the 6th power).  But unfortunately the grand problem is that in a storm, there is a huge variety of drop/flake sizes mixed together at once... such that we can't extract which combination of particle sizes created it (and thus can't calculate volume to actually know the rain/snow amount that falls).  It could be like 6 medium size flakes causing the 10 dBZ echo... or 2 large flakes and 10 small flakes... and each combination is a different volume/snow total.  (&lt;a href=&quot;http://wx.db.erau.edu/faculty/mullerb/Wx365/Radar_equation/radar_equation.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;to see the nitty-gritty math details on this, read more here&lt;/a&gt;.)  So we can never know for sure the exact rain/snow falling using just radar.  The good news is we've at least done lots of experiments and come up with some fairly useful best-practice formulas for using the Z-R ratio in different scenarios.  Good, but not perfect.&lt;/li&gt;&#xA;&lt;li&gt;But when it comes to winter precip, it gets even uglier.  For one, the reflectivity of ice is way more than water (making it look like a ton is falling!)... but we typically can determine where the changeover line to ice is and work from that.  But the bigger issue is that ice crystals form an &lt;a href=&quot;http://www.see.leeds.ac.uk/fileadmin/_processed_/csm_Fig_1_ea4b2879f1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;amazing range of shapes&lt;/a&gt;.  And you can imagine that each of those is going to reflect a radar beam in different percentages... and then take up different amounts of room on the ground.  In the US, the switch to &lt;a href=&quot;http://www.cimms.ou.edu/~schuur/radar.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;polarimetric radar&lt;/a&gt; has helped with the shape issue a fair bit.  But if you don't have that in Japan, you could have quite a bit of error in some formation regimes.  Regardless, we have certainly come up with a few fair rules of thumb for winter precip, such as discussed in &lt;a href=&quot;http://journals.ametsoc.org/doi/pdf/10.1175/1520-0450%281985%29024%3C0068%3ARDOSRA%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt;, but they're far from perfect.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Now that doesn't mean working from radar isn't helpful.  The &quot;precipitation nowcasts&quot; are probably better for you, taking out the complexity of all that Z-R relationship stuff just mentioned to just give you a mm/hr (though the site may well not be taking enough into account to give worthwhile values in all situations).  But you can have some comfort from the fact that in the US we do regularly use basically the same idea to what you're doing to identify floods and even roughly track snowfall areas.  But unfortunately it's a real pity it doesn't seem most countries like Japan offer as many detailed radar products for free as we get.  In the US, the NWS gives us &lt;a href=&quot;https://radar.weather.gov/ridge/lite/NTP/PDT_loop.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;storm-total precipitation&lt;/a&gt; plots directly, which provides us the total return accumulation (since last reset) so we don't have to track the aggregation ourselves.  Plus we have direct access to the full radar data files, which would remove the overcome the value stratification issues from the imagery and simplify the process.  But unfortunately I couldn't find anything about any rawer data files in my searching other than for the &lt;a href=&quot;https://mesonet.agron.iastate.edu/sites/site.php?station=RODN&amp;amp;network=JP__ASOS&quot; rel=&quot;nofollow noreferrer&quot;&gt;US site in Okinawa&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Your method does sounds fairly decent&lt;/strong&gt;, particularly for Nagano since it appears to have it's own radar (based upon that earlier list).  I do imagine it'll still have some errors at times, being off by a fairly decent percentage sometimes.  Even here in the US, we're only just starting to cautiously venture more into more high resolution &lt;a href=&quot;https://www.nohrsc.noaa.gov/nsa/&quot; rel=&quot;nofollow noreferrer&quot;&gt;official snow analyses&lt;/a&gt;.  So it won't be nearly perfect, but it'll probably have some reasonable utility, and perhaps is your best method on this avenue.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I want to give you a couple more options that may well end up being better for you, depending upon your interest:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Initial model plots&lt;/strong&gt;:&lt;br&gt;&#xA;Global models, like the American GFS, use large amounts of data to create their initial conditions.  And so among their products, they offer current snow cover plots.  &lt;a href=&quot;http://www.pivotalweather.com/model.php?m=gfs&amp;amp;p=snod_cm&amp;amp;fh=0&amp;amp;r=as&amp;amp;dpdt=&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pivotal Weather offers a useful tool&lt;/a&gt; to mouseover and get values at any point in a plot like this one:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/vBv7E.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vBv7E.png&quot; alt=&quot;snowplot&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Don't know if it's perfect for you, as the GFS resolution is around 30 km, so even at maximum resolution it's going to lump some mountains and lower areas together.  A pity Pivotal Weather also is a little zoomed out in your area.  If you were really wanting to go all in, you could definitely dig up the data files to download the data directly out of the model for peak resolution and information.  Otherwise if content, you can just check each day (or every 6 hours) and compare to the previous image (which you can pull up in the dropdown on Pivotal's site).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Satellite data&lt;/strong&gt;:&lt;br&gt;&#xA;I was able to come across one satellite that does offer a &lt;a href=&quot;https://neo.sci.gsfc.nasa.gov/view.php?datasetId=MOD10C1_D_SNOW&quot; rel=&quot;nofollow noreferrer&quot;&gt;snow analysis product&lt;/a&gt;, the NASA TERRA/MODIS pair.  On that same page they have &lt;a href=&quot;http://nsidc.org/data/search/#keywords=terra+snow+0.05Deg/sortKeys=score/facetFilters=%257B%257D/pageNumber=1/itemsPerPage=25&quot; rel=&quot;nofollow noreferrer&quot;&gt;a further link to download the data&lt;/a&gt; at 0.05 degree resolution, which would be less than 1 km!!!  I have no idea how good these plots are, but the potential sounds great.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;So just maybe model and satellite can offer to bypass some of the flaws of radar data (though just may add their own challenges).  All of it is likely better than relying on the town's reporting station... it's unfortunate there's a lack of reliable reporting stations on mountains (but it's a problem we have here too, and a matter of simple economics/utility).  But hopefully those help you better get the data you wish for!  Happy skiing :-p&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-01-17T20:00:29.087" LastActivityDate="2018-01-17T20:00:29.087" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13118" PostTypeId="2" ParentId="13105" CreationDate="2018-01-16T21:46:40.970" Score="5" Body="&lt;p&gt;To better pin down the location, I georeferenced the map getting good match of all land and sea features with a reference map. The figure below shows it overlaid over a reference map with seafloor releif:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/mhFnh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mhFnh.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And the location of your mystery Island is were the red dot is, plus a 25 km search radius.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And the coordinates are (Lat/Lon): 17.0619° N, 152.177° E.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It nicely coincides with a seamount, so it might be more than an error on the map (but that seamount acoording to the data in Google Earth is more than a kilometer under the surface). What definitely seem to be an error, is including such island as part of the Northern Mariana Islands, because in all the references and maps I saw, that denomination only covers the 15 islands on the chain to the west.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I did a search for something in that location first looking as MODIS images (250 m resolution) on &lt;a href=&quot;https://worldview.earthdata.nasa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;WorldView&lt;/a&gt; I had to browse trough months of images to get cloud free images, but I couldn't identify any island&#xA;&lt;a href=&quot;https://i.stack.imgur.com/QzZW1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QzZW1.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, if there, it must be tiny.&#xA;After looking at the catalogs for higher resolution images, there are no Landsat images there at all (something that suggest there is no land there) but there are two Sentinel-2 scenes (10 m per pixel), and happily the cloud cover is not too bad.&#xA;I did a search in those two images within the 25 km radius displayed above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the first image&#xA;&lt;a href=&quot;https://i.stack.imgur.com/w2Ni9.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/w2Ni9.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And this is the second&#xA;&lt;a href=&quot;https://i.stack.imgur.com/REczQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/REczQ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And again I didn't found anything.&#xA;Therefore I'm inclined to think that there is nothing. But I can't rule out that something very small can be hidden by the clouds. However, I doubt it.&#xA;If you want to perform the search yourself over a larger search radius, just let me know and I can give you the images.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also searched the &lt;a href=&quot;https://earthref.org/SC/#top&quot; rel=&quot;nofollow noreferrer&quot;&gt;seamount catalog&lt;/a&gt; for those coordinates and the only one that show up is &lt;a href=&quot;https://earthref.org/cgi-bin/sc-s2-list.cgi?database_name=sc&amp;amp;search_start=main&amp;amp;selected_smnt_id=1400&quot; rel=&quot;nofollow noreferrer&quot;&gt;Vlinder Guyot&lt;/a&gt; about 224 km to the East. So there is no information on the one below your mystery island.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, in &lt;a href=&quot;https://link.springer.com/article/10.1134/S1819714016060038&quot; rel=&quot;nofollow noreferrer&quot;&gt;this publication&lt;/a&gt;. It is refereed as &quot;I'l Ichev&quot; and is part of the &quot;Magellan Seamounts&quot;.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/bbwfE.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bbwfE.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also looked over the seamount you suggested (&quot;Pegas&quot; in the above map and located at 16.136° N, 151.968° E approximately), that is about 100 km away from the location pointed on the map you posted, but I didn't found any island there either (on a search box 22x26 km):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/WnUlv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WnUlv.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;After browsing many other maps, I've also failed to find other map showing that Island. However, in a relatively similar location some old maps show &quot;Los Jardines&quot; Island. It is a know &quot;phantom&quot; island, some more info on its &lt;a href=&quot;https://en.wikipedia.org/wiki/Los_Jardines_islands&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia page&lt;/a&gt;. Here a 1932 German map showing it:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/PHtvW.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PHtvW.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Despite it is not in the same location, it might be the source of the confusion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here a list of good quality maps that DO NOT show that island:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.interkart.de/media/catalog/product/r/e/re01020331_1_1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.interkart.de/media/catalog/product/r/e/re01020331_1_1.jpg&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.maps.com/media/catalog/product/cache/1/thumbnail/17f82f742ffe127f42dca9de82fb58b1/p/a/pacific_ring_of_fire_wall_map_42x31.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.maps.com/media/catalog/product/cache/1/thumbnail/17f82f742ffe127f42dca9de82fb58b1/p/a/pacific_ring_of_fire_wall_map_42x31.jpg&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.nationalgeographic-maps.com/media/catalog/product/cache/7/image/8ecabcfb697832bc77ac7e2547ded39f/x/n/xng196910a.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nationalgeographic-maps.com/media/catalog/product/cache/7/image/8ecabcfb697832bc77ac7e2547ded39f/x/n/xng196910a.jpg&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.melbmap.com.au/site/resources/overseas_map_samples/hema_asia_west_pacific_thumbnail_image.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.melbmap.com.au/site/resources/overseas_map_samples/hema_asia_west_pacific_thumbnail_image.jpg&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://universoguia.com/wp-content/uploads/2012/12/mapa_politico_oceania.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://universoguia.com/wp-content/uploads/2012/12/mapa_politico_oceania.jpg&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.gifex.com/images/0X0/2009-11-11-10993/Mapa-Fsico-de-Oceana.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.gifex.com/images/0X0/2009-11-11-10993/Mapa-Fsico-de-Oceana.jpg&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.xxlmaps.com/maps/1/map3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.xxlmaps.com/maps/1/map3.jpg&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-01-17T01:26:16.787" LastActivityDate="2018-01-17T01:26:16.787" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13120" PostTypeId="1" CreationDate="2018-01-17T00:43:07.860" Score="5" ViewCount="210" Body="&lt;p&gt;How would one calculate the minimum mass required for the earth to retain an atmosphere?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we could hypothetically start removing mass from the earth with a star-trek style transporter, how much mass would the earth have to lose before its atmosphere would no longer cling to its surface?&lt;/p&gt;&#xA;" OwnerUserId="12002" LastEditorUserId="12002" LastEditDate="2018-01-17T06:04:37.623" LastActivityDate="2018-01-25T03:50:38.700" Title="minimum mass required for earth to retain its atmosphere?" Tags="|atmosphere|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13122" PostTypeId="1" AcceptedAnswerId="13123" CreationDate="2018-01-17T18:03:15.847" Score="4" ViewCount="619" Body="&lt;p&gt;We have downloaded grib2 files for &lt;a href=&quot;https://nomads.ncdc.noaa.gov/data/gfs4/&quot; rel=&quot;nofollow noreferrer&quot;&gt;GFS model from NOAA&lt;/a&gt; and extracted irradiance (Downwards shortwave radiation flux) data. Following is a sample output for cordinates at [52.0,4.0]:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;|      Timestamp      | Value |&#xA;| 2017-01-01T03:00:00 |   00  |&#xA;| 2017-01-01T06:00:00 |   00  |&#xA;| 2017-01-01T09:00:00 |   00  |&#xA;| 2017-01-01T12:00:00 |   40  |&#xA;| 2017-01-01T15:00:00 |   50  |&#xA;| 2017-01-01T18:00:00 |   20  |&#xA;| 2017-01-01T21:00:00 |   00  |&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;We know that the values are averaged. We doubt that the averaging is performed over a window of 3 hours such as the values between $hour$ and $(hour-3)$ are averaged and assigned to the timestamp at $hour$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We haven't found any documentation explaining this fact. Can you please explain the principle behind averaging and timestamping? A reference will be very helpful.&lt;/p&gt;&#xA;" OwnerUserId="12007" LastEditorUserId="11908" LastEditDate="2019-03-11T21:11:30.087" LastActivityDate="2019-03-11T21:11:30.087" Title="How averaging works in GFS model from NOAA?" Tags="|meteorology|climate|climatology|gfs|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13123" PostTypeId="2" ParentId="13122" CreationDate="2018-01-17T19:14:13.273" Score="5" Body="&lt;p&gt;The GFS is a model, and the model have a given time-step equal or smaller than the time-step of the output, that in this case is 3 hours. Different processes can be computed using different or even multiple time-steps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some of the reported variables are instantaneous, others are cumulative, and others are time averaged.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the documentation for the &lt;a href=&quot;https://dtcenter.org/GMTB/gfs_phys_doc_dev/group__module__radiation__driver.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;GFS radiation driver module&lt;/a&gt; in the &lt;a href=&quot;https://dtcenter.org/GMTB/gfs_phys_doc_dev/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;GFS Operational Physics Documentation&lt;/a&gt;, the Downwards shortwave radiation flux correspond to a time averaged output quantity, meaning that for each model grid cell, its value is stored every internal time step (&lt;em&gt;deltim&lt;/em&gt;) to then report the time-weighted average of all stored values, which is what you get in the 3-hour output.&#xA;However, I don't know what is the exact value used for &lt;em&gt;deltim&lt;/em&gt; or how the time weights are computed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, what you said seem to be pretty much the case. This is that the value reported for timestamp &lt;em&gt;hour&lt;/em&gt; is the average of all the intermediate values computed between &lt;em&gt;hour-3+deltim&lt;/em&gt; and &lt;em&gt;hour&lt;/em&gt; using some time weights schema that is unclear to me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the link above, you can find all the source code for GFS, so it seem that to figure our the details of the time averaging you might need to search in the code where the values of the array &lt;em&gt;fluxr&lt;/em&gt; (that store the intermediate time-step radiation flux values) is averaged and see there how it is done.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-01-18T18:05:46.963" LastActivityDate="2018-01-18T18:05:46.963" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13124" PostTypeId="2" ParentId="10453" CreationDate="2018-01-18T02:37:50.803" Score="2" Body="&lt;p&gt;It is more of a consistency argument: if a constant-depth ocean with much less relative vorticity than planetary vorticity is to stay that way, the flow must be zonal.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If there were significant meridional velocities, they would cause significant meridional displacements of water masses, which would then, by conservation of angular momentum, no longer have small relative vorticity. (Same angular momentum and same depth means same absolute vorticity.  Different planetary vorticity then means different [in the opposite direction] relative vorticity. If planetary vorticity was zero before the displacement, it isn't anymore afterward.)&lt;/p&gt;&#xA;" OwnerUserId="12008" LastActivityDate="2018-01-18T02:37:50.803" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13127" PostTypeId="2" ParentId="6646" CreationDate="2018-01-18T18:47:24.880" Score="1" Body="&lt;p&gt;In seismic acquisition and processing rose plots are essential. Another way to think of these plots is &quot;angular histograms.&quot; This article &lt;a href=&quot;https://www.tgs.com/uploadedFiles/CorporateWebsite/Modules/Articles_and_Papers/Papers/15-orthogonal-waz.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;article&lt;/a&gt; shows   rose plots for a subsurface point using this picture:&lt;a href=&quot;https://i.stack.imgur.com/tlHW6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tlHW6.png&quot; alt=&quot;rose plot for common midpoint&quot;&gt;&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What you are seeing in plots A,B, and C is the the azimuthal coverage of subsurface seismic ray paths for an &quot;average&quot; point in the survey. So in plot A, very near the point there is not much trace density, but further away at azimuths trending to the upper left/lower right there is more density. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, the point was sampled primarily along a NW/SE direction.  In plot B, the survey was shot to sample the points along a NE/SW direction.  In plot C, we see the results of stacking the two surveys.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These plots are critical because sampling the point from different directions gives us new information, and these plots let us see what information we may be lacking in order to design new surveys to add more information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to play around with creating polar plots, I recommend the free software GMT, &lt;a href=&quot;http://gmt.soest.hawaii.edu/projects/gmt/wiki&quot; rel=&quot;nofollow noreferrer&quot;&gt;generic mapping tools&lt;/a&gt; to get started. It can create just about any type of polar plot you want. There are newsgroups and user forums for help as well. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In python, polar and rose plots can also be created different ways, one is &lt;a href=&quot;https://plot.ly/python/polar-chart/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Plotly&lt;/a&gt;. If you are familiar with python, it might work well for you. Below is a sample Plotly rose plot. &lt;a href=&quot;https://i.stack.imgur.com/94KzR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/94KzR.png&quot; alt=&quot;Plotly rose plot&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4926" LastActivityDate="2018-01-18T18:47:24.880" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13128" PostTypeId="2" ParentId="9490" CreationDate="2018-01-18T18:59:49.250" Score="3" Body="&lt;p&gt;In fact, there are many chemical transport models which solve the radical chemistry without steady-state approximations. The equations are very stiff but can be integrated with suitable methods, usually implicit. Some approaches are discussed in &lt;a href=&quot;http://www.mdpi.com/2073-4433/2/3/510&quot; rel=&quot;nofollow noreferrer&quot;&gt;this review&lt;/a&gt;. The &lt;a href=&quot;http://people.cs.vt.edu/~asandu/Software/Kpp/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kinetic Preprocessor&lt;/a&gt;, mentioned in the comment, includes a set solvers for stiff systems and has become somewhat popular in atmospheric chemistry. Some models that use code generated by it (either by default or as an option) include &lt;a href=&quot;http://wiki.seas.harvard.edu/geos-chem/index.php/KPP_solvers_FAQ&quot; rel=&quot;nofollow noreferrer&quot;&gt;GEOS-Chem&lt;/a&gt; and &lt;a href=&quot;https://ruc.noaa.gov/wrf/wrf-chem/wrf_tutorial_2015/WRF_CHEM_Chemistry.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;WRF-Chem&lt;/a&gt;. I used KPP to implement the CB4 chemical mechanism in &lt;a href=&quot;http://silam.fmi.fi&quot; rel=&quot;nofollow noreferrer&quot;&gt;this air quality model&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An approach like this is possible because of operator splitting, which means that the processes included in the model are solved as a sequence of uncoupled operations. For example, a model time step could consist of calling an explicit scheme for solving advection, then Crank-Nicolson for vertical diffusion, and then a Rosenbrock solver for chemical kinetics.&lt;/p&gt;&#xA;" OwnerUserId="859" LastEditorUserId="859" LastEditDate="2018-01-23T21:34:40.417" LastActivityDate="2018-01-23T21:34:40.417" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13131" PostTypeId="1" CreationDate="2018-01-18T22:10:07.460" Score="-5" ViewCount="3657" Body="&lt;p&gt;I've found many claims arguing that the periods of minimum solar activity are associated with increases earthquakes and volcanic activities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some of these claims are supported by articles in scientific format. However, they are not published in mainstream scientific journals (as the ones listed by &lt;a href=&quot;https://www.scopus.com/sources&quot; rel=&quot;nofollow noreferrer&quot;&gt;SCOPUS&lt;/a&gt;), but they seem to show some compelling evidence of the correlation between GSM and earthqueakes. Some of such articles are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://users.neo.registeredsite.com/3/4/0/21850043/assets/qk-volc_and_solarlowcycle.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Volcanic and seismic activities during the solar&#xA;hibernation periods&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://file.scirp.org/Html/5319.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Influences of solar cycles on earthquakes&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://users.neo.registeredsite.com/3/4/0/21850043/assets/newmadridchoi_and_casey.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;New Madrid Seismic Zone, central USA: The great 1811-12 earthquakes, their relationship to solar cycles, and tectonic settings&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://users.neo.registeredsite.com/3/4/0/21850043/assets/newmadrid_and_caribbean.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;The January 2018 M7.5 offshore North Honduras earthquake: its possible energy link to the New Madrid Seismic Zone, Mississippi Valley&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://adsabs.harvard.edu/abs/2007AGUSMIN33A..03J&quot; rel=&quot;nofollow noreferrer&quot;&gt;Whether solar flares can trigger earthquakes?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;They put special emphasis in the association of GSM's with the activity of the New Madrid Fault.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, in the mainstream scientific literature this correlations seem to be ignored. Then I wonder:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is there any real correlation between Grand Solar Minimums and earthquakes?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If there is: How can solar activity affect earthquakes and volcanic activity?&lt;/p&gt;&#xA;" OwnerUserId="606" LastEditorUserId="11908" LastEditDate="2019-03-03T21:07:49.490" LastActivityDate="2019-04-05T21:32:01.373" Title="Is there any correlation between Grand Solar Minimums (GSM) and earthquakes?" Tags="|earthquakes|sun|solar-terrestrial-physics|seismic-hazards|insolation|" AnswerCount="1" CommentCount="22" ClosedDate="2018-01-19T23:02:34.447" ContentLicense="CC BY-SA 4.0" />
  <row Id="13132" PostTypeId="2" ParentId="13131" CreationDate="2018-01-19T00:37:47.750" Score="21" Body="&lt;p&gt;The main proxy that we have of past solar intensity comes from its &lt;a href=&quot;https://spacemath.gsfc.nasa.gov/earth/Earth8.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;proven correlation to the number of sunspots&lt;/a&gt;, which have been recorded since the invention of the telescope in the early 1600's. And the plot looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nwvd6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nwvd6.png&quot; alt=&quot;solar output&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;We have no evidence of any significant correlation between the solar cycle and earthquakes or volcanic activity.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You won't find papers in legitimate peer-reviewed journals regarding the lack of correlation, because generally null results are not of much interest. &#xA;Therefore, I dug up the data myself: Here I've plotted the year count of all of the earthquakes worldwide from 1950 to 2017 of magnitude 7 or greater found in the &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/search/&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS Earthqueake Catalog&lt;/a&gt; (orange), along with the total number of sunspots per year from the &lt;a href=&quot;http://www.sidc.be/silso/datafiles#total&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sunspot Index and Long-term Solar Observations&lt;/a&gt; (blue):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UQwNJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UQwNJ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There doesn't appear to be any significant connection between the two graphs. The solar portion shows the well-proven 11 year solar cycle (actually &lt;a href=&quot;https://scied.ucar.edu/sunspot-cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;it's a 22 year cycle&lt;/a&gt; with two similar halves). And the earthquakes doesn't show any clear pattern.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;There are many fault systems on earth, and if you cherry-pick one (like the New Madrid fault), you might found a correlation just by chance&lt;/strong&gt;, but such correlation have no statistical value. To believe such correlation is even more difficult if there is no physical mechanism proposed for such influence. Nevertheless, as you can see in the graph above, if we include all earthquakes the correlation just doesn't exists.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even for the &lt;a href=&quot;https://en.wikipedia.org/wiki/New_Madrid_Seismic_Zone&quot; rel=&quot;nofollow noreferrer&quot;&gt;New Madrid fault&lt;/a&gt; the correlation is weak. Sure, there was an earthquake in 1699 coinciding with the Maunder minimum, one in 1812 coinciding with the Dalton minimum, and a smaller one in 1895 coinciding with a minor minimum. But what about the one in 1843? That one doesn't match any minimum (let aside several magnitude 5 earthquakes that were recorded during the 20th century grand solar maximum). Also, &lt;a href=&quot;http://www.sidc.be/silso/yearlyssnplot&quot; rel=&quot;nofollow noreferrer&quot;&gt;solar activity is now as low as for the 1895 earthquake&lt;/a&gt; and nothing have happened yet. So you have four points, three of them match your supposed correlation and one doesn't. Such data is far from providing a robust statistical correlation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;After the OP's comments complaining that the above graph, that extends back to 1950 only, is too short to capture the grand solar minimums, I consulted other, arguably impartial database of historical earthquakes beyond the instrumental record: Wikipedia. In particular, its &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_historical_earthquakes&quot; rel=&quot;nofollow noreferrer&quot;&gt;list of historical earthquakes&lt;/a&gt; (before year 1900). I've downloaded the data and created a histogram of earthquakes per decade. Which is presented below together with the most popular reconstruction of solar activity, that is derived from &lt;span class=&quot;math-container&quot;&gt;$^{14}$&lt;/span&gt;C in tree rings (&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Carbon14_with_activity_labels.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;figure source&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FZpo5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FZpo5.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once again, you can see that there is no correlation between earthquakes and grand solar minimums, so you can stop believing that claim based on cherry-picking seismic areas that by chance show a (still questionable) correlation with grand solar minimums.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The solar cycle does indeed have some influence on climate - by changing the intensity of UV radiation, which in turn changes the properties of the upper atmosphere. However, the variation in total energy due to the solar cycles are actually very small (~0.1%). The impacts of those small fluctuations are not large enough to explain the warming observed in the last century, and it does not drive ice ages either (that are triggered by larger factors like &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;nofollow noreferrer&quot;&gt;changes in the earth orbit&lt;/a&gt;, which operate at a MUCH longer timescale [~100,000 years]).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The exact cycle of earthquakes can vary by hundreds of years, and there is still NO way to predict WHEN they will exactly happen with current technology. When enough people make enough predictions that a catastrophic event will happen, some of them will be right. &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_dates_predicted_for_apocalyptic_events&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here is a small sampling&lt;/a&gt; of past apocalyptic forecasts.  You can see that most did not come true. Because earthquakes happen periodically, some people do claim their predictions were right, but those accidental hits can be explained by pure chance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Once again, there is no observed link between solar activity and earthquakes or volcanic activity.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A variant of the supposed correlation between solar minimums and earthquakes is one arguing that solar flares are correlated with earthquakes, something that is also false. &lt;a href=&quot;http://www.thesuntoday.org/solar-facts/flares-and-earthquakes/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; explains it well. &lt;a href=&quot;https://arxiv.org/abs/cond-mat/0602208&quot; rel=&quot;nofollow noreferrer&quot;&gt;Research have pointed that there are some statistical properties that are very similar in both processes&lt;/a&gt;. However, there is no correlation or connection between them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;UPDATE: An updated and extended version of the plot of sunspots versus earthquakes can be found in my answer to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/14370/what-would-a-graph-of-magnitude-7-5-earthquakes-over-last-400-years-compared-to/14846#14846&quot;&gt;this question&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-04-05T21:32:01.373" LastActivityDate="2019-04-05T21:32:01.373" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="13133" PostTypeId="2" ParentId="7885" CreationDate="2018-01-19T02:31:45.363" Score="2" Body="&lt;p&gt;In less arid times vegetation grows on the dunes and stabilizes them.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Paleoclimate proxy data and computer simulations reveal that the Nebraska Sandhills likely had active sand dunes as recently as the Medieval Warm Period, when temperatures in the North Atlantic region[4][5] were about 1°C (1.8°F) warmer than the current climate. &lt;a href=&quot;https://en.wikipedia.org/wiki/Sandhills_(Nebraska)#Paleoclimate_and_future&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;&#xA;  &lt;a href=&quot;https://i.stack.imgur.com/lUGMT.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lUGMT.jpg&quot; alt=&quot;Nebraska Sandhills&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A thin layer of topsoil is formed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.registrelep-sararegistry.gc.ca/default.asp?lang=En&amp;amp;n=42B8444C-1&amp;amp;offset=5&amp;amp;toc=show&quot; rel=&quot;nofollow noreferrer&quot;&gt;Aerial photographs of the Spirit Dunes&lt;/a&gt;, Manitoba, Canada show this can happen in decades:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/NGeYT.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NGeYT.gif&quot; alt=&quot;Spirit Dunes&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Sahara dunes were still there during fertile times - they were just grown over with grass. When conditions became arid, what little topsoil there was blew away and/or was mixed with the sand.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2018-01-20T20:01:42.777" LastActivityDate="2018-01-20T20:01:42.777" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13134" PostTypeId="1" AcceptedAnswerId="13143" CreationDate="2018-01-19T18:46:39.660" Score="5" ViewCount="176" Body="&lt;p&gt;Would the &lt;a href=&quot;https://en.wikipedia.org/wiki/Enthalpy_of_fusion&quot; rel=&quot;nofollow noreferrer&quot;&gt;enthalpy of fusion&lt;/a&gt; for melting ice fields be a causative factor for colder winter weather?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an example, NASA estimated the annual loss of the Greenland ice field 2002-2013 as more than 280 gigatons, and apparently increasing.  Would the energy required for state transition on such a scale be a causitve factor in colder weather during a period of warming climate?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;UPDATED:  My wording above was too generalized and I got good answers to a question slightly different than the one I intended.  Retry:&#xA;According to Wikipedia, one of the vortices of the northern Polar vortex is Baffin Island, very near Greenland.  The recent unusually cold weather in the eastern US has been attributed to the path of the Polar Vortex this year. My question should have been &quot;could the energy required for state transition of the Greenland ice field contributed to the change in path of the Northern Polar Vortex this year?&quot;&lt;/p&gt;&#xA;" OwnerUserId="12029" LastEditorUserId="11908" LastEditDate="2019-03-11T21:29:41.780" LastActivityDate="2019-03-11T21:29:41.780" Title="Would the enthalpy of fusion for melting ice fields be a causative factor for colder winter weather?" Tags="|meteorology|atmosphere|climate|glaciology|ice-sheets|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13139" PostTypeId="2" ParentId="11941" CreationDate="2018-01-20T20:58:55.933" Score="2" Body="&lt;p&gt;Something that I noticed in your formula is that you are using 365 for the amount of days in a year.  Perhaps trying it using 365.25 would be more correct as it accounts for the leap year.  Please let me know if this helps/corrects the issue.&lt;/p&gt;&#xA;" OwnerUserId="12037" LastActivityDate="2018-01-20T20:58:55.933" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13140" PostTypeId="1" CreationDate="2018-01-21T01:45:04.200" Score="4" ViewCount="320" Body="&lt;p&gt;I was wondering if anyone knows how the formation of the &lt;a href=&quot;https://en.wikipedia.org/wiki/West_Mata&quot; rel=&quot;nofollow noreferrer&quot;&gt;West Mata volcano&lt;/a&gt; came to be? I was reading that a lot of underwater volcanoes were formed by convergent boundary. Is this how West Mata was created?&lt;/p&gt;&#xA;" OwnerUserId="12039" LastEditorUserId="6298" LastEditDate="2018-01-21T22:59:57.023" LastActivityDate="2018-01-30T19:16:50.237" Title="The formation of West Mata" Tags="|volcanology|plate-tectonics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13142" PostTypeId="2" ParentId="13134" CreationDate="2018-01-21T06:55:05.177" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Would the enthalpy of fusion for melting ice fields be a causative factor for colder winter weather?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No, for a number of reasons.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Ice sheets melt in the summer and rebuild in the winter. This is winter.&lt;/li&gt;&#xA;&lt;li&gt;The enthalpy of fusion for water is 333.55 joules per gram. Multiply that by 280 gigatons per year and you get 9.3×10&lt;sup&gt;16&lt;/sup&gt; joules per year. While that sounds like a lot, it's a blip compared to the 5.5×10&lt;sup&gt;24&lt;/sup&gt; joules the Earth receives from the Sun every year.&lt;/li&gt;&#xA;&lt;li&gt;It's not a cold winter. While it has been an abnormally cold winter for the eastern parts of the U.S. and Canada, the rest of the northern hemisphere has been rather balmy. Nuuk, Greenland, for example, is suffering a heat wave. The current (06:38 UTC 21 January 2018) temperature there is 3°C (37° F), significantly warmer than average. The normal high for that location at this time of year is -6°C (24° F).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The melting of all that ice might well have an impact on climate, but it's the influx of 280 gigatons (and rising) of fresh water every year into the northern ocean rather than a paltry absorption of 10&lt;sup&gt;17&lt;/sup&gt; joules of energy every year that will be the cause.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2018-01-21T07:00:45.093" LastActivityDate="2018-01-21T07:00:45.093" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13143" PostTypeId="2" ParentId="13134" CreationDate="2018-01-21T19:44:24.117" Score="3" Body="&lt;p&gt;The short answer is YES, but with a very important caveat. It won't be colder than usual, but colder than it would have been if the Greenland ice sheet weren't there to absorb that heat, and by a very small amount.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is true for the mean global temperature, but when it comes to the actual strength of one winter season in a particular location, the atmospheric patterns play a much bigger role than the melting of ice sheets.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The latent heat (i.e. Enthalpy of fusion) of water is huge. The amount of energy needed to turn 0°C ice into 0°C water is the same as the amount required to heat up 0°C water to 80°C. Therefore, ice sheets and glaciers have a buffer effect on climate, as they are able to absorb a large amounts of energy without an increase in temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3o16E.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3o16E.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;Figure: Temperature curve of water as heat is added to 18g of water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Despite of that, it is still a very small amount on the overall energy budget of the Earth, let's do the math:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;280 Gt/year = 2.8e17 g/year&#xA;Latent heat = 333.55 J/g = 0.09 Wh/g&#xA;Total latetent heat = 2.8e17 g/year * 0.09 Wh/g = 2.5e16 Wh/year&#xA;That means a energy flux of 2.5e16/(365*24) = 2.8e12 W&#xA;Earth surface = 5.1e14 m²&#xA;Equivalent radiative forcing = 2.8e12/5.1e14 = 0.006 W/m²&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Which is very small, in fact about a 0.4% of the radiative forcing associated to CO2 (see figure below):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SB0mk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SB0mk.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem is that the resulting water have a impact in sea level rise and seawater salinity, that can in turn have an effect on ocean currents, deep water formation and other phenomena that can change the heat redistribution on earth. On the other hand, the reduction of ice sheets increase the albedo (because the bare ground absorb more energy than snow or ice), so that at the end the Earth will capture more energy leading to a positive feedback. Also, as the ice sheets get thinner, they will receive less snow (and more rain), therefore enhancing further reduction of the ice mass.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, I have to add that when it comes to ice sheet models and climate models, the latent heat is always taken into account and if there were no latent heat, the figure for anual ice loss would be much bigger than 280 Gt.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-01-21T21:18:44.443" LastActivityDate="2018-01-21T21:18:44.443" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13144" PostTypeId="1" AcceptedAnswerId="13161" CreationDate="2018-01-21T20:57:58.510" Score="15" ViewCount="2794" Body="&lt;p&gt;The different gases that make up the air have different densities. So, naively, one would expect the heavier gasses to pool in the lower atmosphere and the light ones at the top.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I asked myself this question a long time ago and I found the answer to be that the mixing produced by atmospheric circulation was more than enough to keep the whole mix homogeneous, and I was happy with that answer until I considered the case of caves, or chambers within the Earth that have been discovered in underground mines, and that have been isolated for millions of years. But despite of that, there is no reports of miners dying because on the top of the cavity the air was only nitrogen or oxygen at the bottom.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is the mixing produced by molecular movement due its temperature enough to avoid stratification? Or is there another reason? Would air at very low temperature suffer from density stratification?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2021-02-21T16:30:27.413" Title="Why air do not suffer density stratification of its gaseous components?" Tags="|atmosphere|gas|air|" AnswerCount="2" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="13145" PostTypeId="1" CreationDate="2018-01-22T00:02:03.153" Score="2" ViewCount="144" Body="&lt;p&gt;Low visibility, say &amp;lt;1km (3300 ft), can be caused by fog when there is no/little wind present.  On the other hand, high winds associated with blizzards or wildfires can also create low visibility environments.  Living in a temperate climate I'd be inclined to believe that a lack of wind is the most likely cause because fog seems to be more common, however I'm not sure if this would be the case when other latitudes are also taken into consideration.   &lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2018-03-01T16:02:34.770" Title="Are high velocity winds, or the lack of wind, the most common cause for low visibility?" Tags="|meteorology|wind|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13146" PostTypeId="1" CreationDate="2018-01-22T00:20:19.510" Score="6" ViewCount="3692" Body="&lt;p&gt;In Google Maps, I don't see any boundary between the Karakoram (a.k.a. Karakorum) Range, the Hindu Kush, and the Himalayan Range. What separates these ranges?&lt;/p&gt;&#xA;" OwnerUserId="12045" LastEditorUserId="94" LastEditDate="2018-02-08T16:07:42.357" LastActivityDate="2018-06-30T17:11:44.173" Title="What separates the Karakoram Range, the Hindu Kush, and the Himalayan Range?" Tags="|geology|plate-tectonics|mountains|terminology|geomorphology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13147" PostTypeId="2" ParentId="13078" CreationDate="2018-01-22T00:40:30.440" Score="3" Body="&lt;p&gt;I suspect that the answers you seek lie as much in computer graphics and human perception as they do in physics or earth science - for example, colours on a cloudy day won't actually be significantly less saturated than on a sunny one - it's still white light to most intents and purposes - but we may perceive them that way due to the differences in contrast, illuminance, and colour.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are three components to natural light :&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can calculate the angle of the sun according to time of year, time of day, and latitude. From this angle, and the altitude of your viewpoint, you can estimate the colour of the direct sunlight. The more air it has to travel through, the lower the colour temperature and the intensity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then you need to consider the blue sky. This will be lighter at low altitude and darker at high. You'll need to do something about the sunwards sky not being blue at low sun angles. The blue sky casts light on things, but this is mostly only evident by shadows appearing a bit bluer than their surrounds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then you need to consider cloud cover. For a flight sim this is complicated by the fact that it may be above or below the camera, or you might be in it. One approach might be to treat clouds as large diffusers that act on the light from the sun and from the blue sky. Whether this is feasible is beyond my ken, and definitely lies in the realm of computer graphics, not earth science. &lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2018-01-22T00:40:30.440" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13148" PostTypeId="2" ParentId="8806" CreationDate="2018-01-22T00:59:10.227" Score="7" Body="&lt;p&gt;There is also a hypersaline periodic water flow, which although a few times more saline than sea water, I might be hesitant to call a river.  However, due to its high salinity (well above everything else mentioned here), I thought it was worth mentioning.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Blood_Falls&quot; rel=&quot;nofollow noreferrer&quot;&gt;Blood Falls&lt;/a&gt;. It is the periodic &lt;a href=&quot;https://www.forbes.com/sites/trevornace/2017/04/28/mystery-of-antarcticas-blood-falls-is-finally-solved/#2904f6992ef8&quot; rel=&quot;nofollow noreferrer&quot;&gt;draining&lt;/a&gt; of a brine reservoir under the Tylor glacier in the &lt;a href=&quot;https://en.wikipedia.org/wiki/McMurdo_Dry_Valleys&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dry Valleys&lt;/a&gt; of Antarctica.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wRw9H.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wRw9H.jpg&quot; alt=&quot;blood falls&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="6298" LastEditDate="2018-02-26T06:22:00.523" LastActivityDate="2018-02-26T06:22:00.523" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13149" PostTypeId="1" CreationDate="2018-01-22T10:27:12.363" Score="7" ViewCount="702" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Rasputitsa&quot; rel=&quot;noreferrer&quot;&gt;rasputitsa&lt;/a&gt; is a muddy season that happens twice per year in West Russia, Ukraine, and Belarus. It happens in mid-October to late November due to rains, and mid-March to late April due to thaws (according to the &lt;a href=&quot;https://ru.wikipedia.org/wiki/%D0%A0%D0%B0%D1%81%D0%BF%D1%83%D1%82%D0%B8%D1%86%D0%B0&quot; rel=&quot;noreferrer&quot;&gt;Russian wiki page&lt;/a&gt; with google translate). These conditions make travel by dirt road almost impossible, as made famous during WW2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I'd want to know is, does Siberia and Canada also have rasputitsas? If so, what times of the year do they occur? and are they comparable to the West Russian one?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt; I should have specified this, but Siberia and Canada are large places. I would guess there's an arctic limit somewhere, to the north of which never gets muddy since it's always too cold. So I guess what I'm asking is, what regions of Siberia and Canada have rasputitsas (if any)?&lt;/p&gt;&#xA;" OwnerUserId="2733" LastEditorUserId="2733" LastEditDate="2018-01-22T13:48:15.593" LastActivityDate="2019-05-29T18:28:36.590" Title="Do Siberia and Canada have a rasputitsa?" Tags="|meteorology|rainfall|seasons|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13150" PostTypeId="1" CreationDate="2018-01-22T10:51:48.333" Score="1" ViewCount="43" Body="&lt;p&gt;I have 3 years weather data of a region in Austria, and I want to classify a year to dry, normal and wet periods, how I can analyse this data of such climate?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="11585" LastEditorUserId="12057" LastEditDate="2018-01-29T22:00:24.993" LastActivityDate="2018-01-29T22:00:24.993" Title="classifying the actual weather data of Cfb climate to dry, normal and wet periods" Tags="|meteorology|" AnswerCount="0" CommentCount="1" ClosedDate="2018-02-12T10:49:02.543" ContentLicense="CC BY-SA 3.0" />
  <row Id="13151" PostTypeId="1" CreationDate="2018-01-22T12:28:15.420" Score="5" ViewCount="197" Body="&lt;p&gt;We receive EUMETCAST data with different formats in our local station, I am having the most difficulty when trying to read or sometimes even know the format of a specific data product, in this case, we are getting data from a product called &lt;strong&gt;GOME-2 GDS Level 1B - Metop&lt;/strong&gt; in a format called PFS, I don't even know what this format is and how to read it or transform it into a more suitable format for data analysis tasks (like CSV):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NdYCg.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NdYCg.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried to look for tools to read this type files and EUMETSAT file in general with no results, I've already read IASI related files in another format (&lt;a href=&quot;http://www.elnath.org.uk&quot; rel=&quot;nofollow noreferrer&quot;&gt;BUFR&lt;/a&gt;) but every new format is a new challenge. in the case of this type of files, I installed &lt;a href=&quot;http://stcorp.nl/coda/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CODA&lt;/a&gt; with no success since it reads only EPS EUMETSAT data and not EUMETCAST formats, I tried using one of EUMETSAT own internal tools called &lt;a href=&quot;https://www.eumetsat.int/website/home/Data/DataDelivery/SupportSoftwareandTools/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;kai&lt;/a&gt; with no success (it requires another lib which is no longer supported by EUMETSAT). When I simply open the file I am getting a series of special characters after the header, like in the following image :&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XCUb4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XCUb4.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any hint or suggestion on how to read the data or EUMETCAST data in general?&lt;/p&gt;&#xA;" OwnerUserId="12049" LastEditorUserId="12049" LastEditDate="2018-01-22T13:39:44.053" LastActivityDate="2018-01-25T04:28:40.777" Title="How to read EUMETCAST GOME-2 data?" Tags="|remote-sensing|software|data-formats|satellites|" AnswerCount="0" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="13152" PostTypeId="2" ParentId="13144" CreationDate="2018-01-22T13:25:15.280" Score="6" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;But despite of that, there is no reports of miners dying because on the top of the cavity the air was only nitrogen or oxygen at the bottom.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes and no, miners die from other causes, like lack of oxygen, sulphur poisoning, etc.&lt;br&gt;&#xA;But for example you can already get a case of sulphur poisoning near &lt;a href=&quot;https://en.wikipedia.org/wiki/Fumarole&quot; rel=&quot;noreferrer&quot;&gt;Fumaroles&lt;/a&gt; in volcanic regions, simply because the air that has the sulphur dissolved in it is heavier than the surrounding air.&lt;br&gt;&#xA;So that's the effect you have been asking for, but you still need a severe lack of wind and the right topography to make the stratification happen.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So now let's zoom out a bit. Earth has a surface. This provides friction and slows down surface winds considerably, creating the &lt;a href=&quot;https://en.wikipedia.org/wiki/Planetary_boundary_layer&quot; rel=&quot;noreferrer&quot;&gt;Planetary boundary layer&lt;/a&gt; (PBL). You can think of the PBL as 'what the free-streaming atmosphere would want to do, but then it encounters a surface'.&lt;br&gt;&#xA;Only because of the friction of the surface, we have only moderately strong winds on the surface that allow for special phenomena like little valleys filled with sulphur.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Higher up in the atmosphere velocities are much faster. Thus, Reynolds numbers are higher, destabilization of flows comes easier and turbulence sets in, mixing everything.&lt;br&gt;&#xA;Only at the Karman-line around 100km height, things calm down sufficiently (in terms of frictional momentum density transfer from layer to layer) that molecules start separating by weight.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I would say your initial intuition was right, it's just less intuitive how the planetary surface plays into this.&lt;br&gt;&#xA;In the oceans btw. this phenomenon plays a huge role in determining global circulation. The different &lt;a href=&quot;https://en.wikipedia.org/wiki/Salinity&quot; rel=&quot;noreferrer&quot;&gt;salinity&lt;/a&gt; of water layers leads to different densities and layered flows. And because the density of water is a factor of $10^6$ higher than that of air, one would need a much stronger source of momentum to mix those layers. But such a source doesn't exist, so we get layered flows of different densities.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2018-01-22T13:25:15.280" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13153" PostTypeId="1" CreationDate="2018-01-22T17:02:14.067" Score="3" ViewCount="74" Body="&lt;p&gt;I was reading an article on fluid dynamics of tropical cyclones, where I came across a condition which states that,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;For adiabatic friction less flow, equations (1) to (5) have a&#xA;  solution, v(r, z), for a steady freely spinning vortex in which u and&#xA;  w are identically zero and v(r, z) is an arbitrary function of r and&#xA;  z.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Where these 5 equations are basic primitive equations (2 horizontal and 1 vertical equation of motion,conservation of mass and thermodynamic equation) written in cylindrical coordinates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I try to consider the horizontal(u component only) and vertical equations of motion when they are in gradient wind and hydrostatic balance, u and w will be conserved i.e du/dt=0 and dw/dt=0.&#xA;How can one conclude that they are identically zero?&#xA;For the article, please open the following link &#xA;&lt;a href=&quot;https://www.google.co.in/url?sa=t&amp;amp;source=web&amp;amp;rct=j&amp;amp;url=https://www.meteo.physik.uni-muenchen.de/~roger/Publications/M17.pdf&amp;amp;ved=2ahUKEwjvzPOsmOzYAhUeSo8KHf3wC5YQFjAEegQIDRAB&amp;amp;usg=AOvVaw3uxV6Wyli4JcGq3qrQzR00&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.google.co.in/url?sa=t&amp;amp;source=web&amp;amp;rct=j&amp;amp;url=https://www.meteo.physik.uni-muenchen.de/~roger/Publications/M17.pdf&amp;amp;ved=2ahUKEwjvzPOsmOzYAhUeSo8KHf3wC5YQFjAEegQIDRAB&amp;amp;usg=AOvVaw3uxV6Wyli4JcGq3qrQzR00&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The primitive equations are given in section 2.1 and the lines highlighted above are taken from the first paragraph of section 2.2&lt;/p&gt;&#xA;" OwnerUserId="11162" LastEditorUserId="11162" LastEditDate="2018-01-22T18:33:00.887" LastActivityDate="2018-01-22T18:33:00.887" Title="Why does the absence of diabatic heating rate and frictional terms make the zonal and vertical velocity identically zero?" Tags="|atmosphere|tropical-cyclone|mesoscale-meteorology|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13155" PostTypeId="1" CreationDate="2018-01-23T01:09:27.020" Score="3" ViewCount="63" Body="&lt;p&gt;The island of St Helena was volcanically active for five million years or longer. The island is located on the African plate and in that period of time would have moved at least a hundred miles or more. Surely the idea of a single hot spot cannot apply in such a case - it seems more akin to a hot streak. I also wonder whether other mid-oceanic volcanoes were active for similar lengthy periods and whether or not these conform to the idea of single hot spots.&lt;/p&gt;&#xA;" OwnerUserId="12054" OwnerDisplayName="user8654" LastActivityDate="2018-01-23T08:17:35.857" Title="Is the theory of hot spots compatible with lengthy volcanism?" Tags="|ocean|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13156" PostTypeId="2" ParentId="13155" CreationDate="2018-01-23T08:17:35.857" Score="2" Body="&lt;p&gt;Tectonic plates are not single blocks of geology. The &lt;a href=&quot;https://en.wikipedia.org/wiki/African_Plate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Africa Plate&lt;/a&gt;, like other tectonic plates, consist of cratons  which are &quot;&lt;strong&gt;stable blocks of old crust with deep roots in the subcontinental lithospheric mantle, and less stable terranes, which came together to form plates&lt;/strong&gt;&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Africa Plates contains the &quot;Kalahari craton, Congo craton, Tanzania craton and West African craton&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The island and volcano of &lt;a href=&quot;https://en.wikipedia.org/wiki/Saint_Helena&quot; rel=&quot;nofollow noreferrer&quot;&gt;St Helena&lt;/a&gt;, though on the edge of the Africa Plate, is more associated with the Mid Atlantic Ridge than it is with the Africa Plate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cratons and other land masses that form the Africa Plate may be mobile, but St Helena and the Mid Atlantic Ridge are not.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-01-23T08:17:35.857" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13157" PostTypeId="1" AcceptedAnswerId="13160" CreationDate="2018-01-23T10:34:34.290" Score="2" ViewCount="76" Body="&lt;p&gt;I am puzzled by the dimensions of the formulas given &lt;a href=&quot;http://www.rsmas.miami.edu/users/lbeal/MPO603/Lecture%2012.xhtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; for the baroclinic component of ocean currents (first terms on the right-hand side of formulas 5 and 6).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I am not wrong:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[f]=1/s&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[$\rho$]=kg/m3&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[$\frac{\partial}{\partial y}$]=1/m&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[dz]=m&lt;/p&gt;&#xA;&#xA;&lt;p&gt;therefore:&#xA;$$[\frac{1}{f\rho}\frac{\partial}{\partial y}\int_{-z}^0\rho(z)dz]=s\frac{m^3}{kg}\frac{1}{m}\frac{kg}{m^3}m = s$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What am I missing?&lt;/p&gt;&#xA;" OwnerUserId="6001" LastActivityDate="2018-01-23T12:23:54.627" Title="baroclinic current - dimensional analysis" Tags="|oceanography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13159" PostTypeId="1" AcceptedAnswerId="13198" CreationDate="2018-01-23T11:14:02.643" Score="6" ViewCount="5211" Body="&lt;p&gt;I would like to ask how to calculate the relative humidity that a heated indoor area would have using only outside temperature and outside relative humidity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found the Relative Humidity Calculator at &lt;a href=&quot;https://www.lenntech.com/calculators/humidity/relative-humidity.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.lenntech.com/calculators/humidity/relative-humidity.htm&lt;/a&gt;.&#xA;I tried to understand the source code, but I am confused with the formulas (absMoisture1, RH2) used for the calculation of relative humidity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please, have you ever face up to the similar problem? &#xA;Many thanks in advance. &lt;/p&gt;&#xA;" OwnerUserId="12053" LastEditorUserId="11908" LastEditDate="2018-01-27T20:18:38.760" LastActivityDate="2021-06-20T09:35:17.903" Title="How to calculate humidity using outside temperature and outside relative humidity?" Tags="|meteorology|atmosphere-modelling|humidity|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13160" PostTypeId="2" ParentId="13157" CreationDate="2018-01-23T12:23:54.627" Score="2" Body="&lt;p&gt;They are missing $g$ in equations 4,5 and 6. When they go from the hydrostatic equation to equation 4, they forget to include gravity in their equations.&#xA;All the dimensions except from $g$ and $f$ compensate each other and then $g/f$ produces the right velocity dimensions $m/s$.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2018-01-23T12:23:54.627" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13161" PostTypeId="2" ParentId="13144" CreationDate="2018-01-23T13:20:48.187" Score="8" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;So, naively, one would expect the heavier gasses to pool in the lower atmosphere and the light ones at the top.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That's overly naive. That same naive expectation would lead one to think that uranium should be concentrated in the Earth's core, or that a mix of water and ethanol should be differentiated with water on the bottom and ethanol on top. Uranium is instead concentrated in the Earth's crust, and water and ethanol readily mix. Entropy and chemistry can lead to counterintuitive results.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That most certainly is the case with gases. The entropically-favored distribution is a thorough mix. Attaining this thorough mix can take a long time if only molecular diffusion is in play. Turbulent mixing makes the mixing proceed much more rapidly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are places where this entropically-favored distribution does not occur. Gases can be concentrated in mines and in basements. For example, mines have problems with concentrations of methane and carbon monoxide (both less dense than air), but also with concentrations of carbon dioxide and sulfur sulfide (both more dense than air). Basements in areas with lots of granite have problems with radon (significantly more dense than air). Gases can concentrate in mines and basements due to a diminished turbulent mixing. This enables processes that produce gases to overwhelm the slow molecular dispersion process, resulting in an entropically-disfavors distribution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth's upper atmosphere is also differentiated. Here, the extreme rarity of the upper atmosphere means that turbulent mixing is highly attenuated. Extreme solar radiation (high UV and x-rays) produces gases by splitting molecular oxygen, water vapor, and to a lesser extent, nitrogen, into constituent parts. The very long mean free path in the upper atmosphere means that the lighter components move higher than do the heavier components.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-01-23T13:20:48.187" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="13162" PostTypeId="1" AcceptedAnswerId="13163" CreationDate="2018-01-23T14:36:43.050" Score="3" ViewCount="90" Body="&lt;p&gt;Based on multiple site sampling of airborne $PM_{2.5}$ and $PM_{10}$ , the elemental concentrations of the trace elements were analyzed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have found out in the site near surface coal mining zone presenting ~3-4 times of heavy metals ($As$, $Cd$ and $Pb$) compared to those of in other sites (~ 50 km away from the coal-production zone).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The receptor-oriented source apportionment tool was also applied, with a special factor could be identified which has high loading of element Cd, As, Pb.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, I infered that this factor might be attributed to coal mine dust.  Since Zn, Cd, Pb were all existed in coal seams as some minerals and they can be emitted in the coal mining, transportation activities. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since there have been none similar research pointing out this factor, I was doubt about the rationality of my judgement. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;More detailed description are depicted as follows:    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1) This factor was only show apperaent contribution on the site near coal mine area&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) This factor can be produced in PMF analysis for both  $PM_{2.5}$ and $PM_{10}$ samples, respectively.  If I removed the dataset of the corresponding site, this factor will be gone in the source identification analysis. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some &quot;negative&quot; information:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1) The wind direction factor was also implemented. The source variability was not well in accordance with the wind field (As expected, the high contribution of coal mine dust should occurs in the time when the wind is coming from the direction of coal mining area)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) Combining with a prior knowledge, the source profile for coal mine dust (upper soil by wind-blown process) should enriched in coarse particles, while the high proportions of $As$, $Cd$, $Pb$ in $PM_{2.5}$/$PM_{10}$ were still founded in the coal-mining site.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The figures followed was the emission features of coal combustion and &quot;coal mine dust&quot;(inferred by myself).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/408Lq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/408Lq.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MkzaM.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MkzaM.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not well satisfied with my interpretation on the apportionment results. I will be grateful if some researchers shed some light on this issue.    &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;More information on the sampling sites&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;PM samples are simultaneously collected in six sites within the studied area in daily basis. As a energy base area, there are 8 coal-fired power stations within this area.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Site 1 was located near coal mine as the following figure. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Hmgzz.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Hmgzz.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;More information on the source identification.&lt;/h3&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;One factor can be identified in all sites, with high mass loading of Na, Cr, As, Zn, Pb. These trace elements existing in coal can be volatilized in high temperature combustion processes and then coagulated into solid phase in atmosphere.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The seasonal variability of this factor also show the trend of &lt;strong&gt;highest contribution in winter&lt;/strong&gt;. It might indicate the increasing coal combustion for domestic heating which is common in north China. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, I inferred this factor was the emission from coal combustion (coal-fired power/heating plant and domestic uses of bulk coal).&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The other factor which was similar with the factor in the source profile. High mass loading of As, Cd, Pb was also founded. Meanwhile, this factor presented elevated contribution only at the site near surface coal mining zone. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, I thought this factor should be the emission of coal mining activity. &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Information of the coal mining&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Responding to first answer, I investigated the coal mining activity in this area. Here is an figure of  one of the coal strip mine and the coal is mined by mechanical cutting techniques.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/r9Z9q.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/r9Z9q.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="5214" LastEditDate="2018-01-24T03:13:09.607" LastActivityDate="2018-01-24T03:13:09.607" Title="The influence of special emissions (possibly coal mining activity) on particulate matters" Tags="|mineralogy|air-pollution|atmospheric-chemistry|environmental-protection|atmospheric-dust|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13163" PostTypeId="2" ParentId="13162" CreationDate="2018-01-23T15:00:31.963" Score="3" Body="&lt;p&gt;The first thing to consider is, if it is not the adjacent coal mine, what other nearby sources could produce such a result. Is there a coal fired power station or a factory nearby. If there are no other likely sources then the coal mine is still the most likely candidate as the source of the dust and metal contaminants.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other thing to consider is how is the coal being mined in the open pit and how is dust being generated by the coal mine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most likely method of mining the coal would require the use of explosives and blasting. This can create large clouds of dust that can be high and wide. If the wind was not blowing when a blast occurred the dust may have reached your sensors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the coal is mined by mechanical cutting techniques dust will still be generated, but not in the same quantities as blasting produces.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other ways dust is generated is by vehicles travelling on unsealed roads - the tyres of the vehicle churn up the dust on the roads.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Dust can also be blown from trucks loaded with coal or from conveyor belts conveying coal to a dump site. The loading of trucks will also generate dust, as will the dumping of coal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From experience, the only way to control dust is to constantly spray with water. Do you know if the mine uses any for of dust suppression?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is well known that coal contains all types of contaminants, including metals such as cadmium and mercury. Different deposits have different types and degrees of contaminants. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From what you have presented, the coal mine is the most likely source of the dust and metal contamination.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-01-23T15:00:31.963" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13166" PostTypeId="2" ParentId="8133" CreationDate="2018-01-23T22:37:54.077" Score="0" Body="&lt;p&gt;Are there? Sure. For example, any water molecule that undergoes a chemical transformation. For example, the chemical equation $$\ce{CO_{2(aq)} + H_2O &amp;lt;--&amp;gt; HCO_{3}^-_{(aq)} + H^-_{(aq)}}$$ destroys the water molecule to create ions. Now since it is a reversible reaction, it is arguable whether or not the molecule is actually destroyed. However, once the reaction $$\ce{Ca^{2+}_{(aq)} + 2HCO_{3}^-_{(aq)} &amp;lt;--&amp;gt; CaCO_3 + CO_{2(aq)} +H_2O}$$ occurs, than the &lt;em&gt;original&lt;/em&gt; molecule is arguably destroyed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;An underlying assumption: I am considering a water molecule to never have been evaporated if it at some point is destroyed (i.e. the atoms no longer make up water).&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2018-01-23T22:37:54.077" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13167" PostTypeId="1" AcceptedAnswerId="13177" CreationDate="2018-01-24T10:36:49.983" Score="3" ViewCount="370" Body="&lt;p&gt;In &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0967063709001344?via%3Dihub&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; paper the author calculated the barotropic component $u_{bt}$ of the current $u$ as: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the vertical mean velocity weigthed with the depth differences&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;If I am not wrong, in a continuous case, this translates to:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ u_{bt} = \frac{1}{d}\int_{-d}^{0}u(z)~dz$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, supposing the current to be geostrophic, the following expression can be found for the barotropic component:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ u_{bt} = -\frac{g}{f}\frac{\partial \eta}{\partial y} $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $g$ is the gravity acceleration, $f$ the Coriolis parameter and $\eta$ the SSH anomaly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are these two expressions equivalent? If yes, why? If not, which are the differences between the hypothesis at the base of the two expressions?&lt;/p&gt;&#xA;" OwnerUserId="6001" LastEditorUserId="6001" LastEditDate="2018-01-24T23:13:04.300" LastActivityDate="2018-01-26T15:13:55.047" Title="barotropic component definition" Tags="|oceanography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13171" PostTypeId="1" AcceptedAnswerId="13174" CreationDate="2018-01-24T18:24:53.057" Score="8" ViewCount="3800" Body="&lt;p&gt;If you were born in the most recent ice age, how different would your life be compared to how you live it today? Furthermore, if humans currently lived in an ice age, how would it affect life &lt;em&gt;today&lt;/em&gt;?&lt;/p&gt;&#xA;" OwnerUserId="12057" LastEditorUserId="11908" LastEditDate="2018-03-16T16:59:33.083" LastActivityDate="2020-05-10T08:15:01.763" Title="What would it be like to live in an ice age?" Tags="|climate-change|earth-history|glaciology|ice-age|glaciation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13174" PostTypeId="2" ParentId="13171" CreationDate="2018-01-24T20:57:10.767" Score="14" Body="&lt;p&gt;It depends where, the continental landmasses at higher latitudes would be covered by massive ice sheets. Therefore the life in the sections of the US and Europe that are close to the Ice sheets would have conditions similar to what is life in Greenland today. The map would look like this:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/MFy13.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MFy13.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Image taken from &lt;a href=&quot;http://www.planetaryvisions.com/Project.php?pid=2226&quot; rel=&quot;nofollow noreferrer&quot;&gt;planetaryvisions.com&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And the summers would be more mellow than what you are used to. Mean global temperatures would be much lower but at tropical latitudes there would still be warm weather. That means that the temperature gradient between the equator and the poles would be larger, leading to quicker climatic transitions as you travel North or South, and also leading to stronger winds and probably more powerful storms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also the sea level would be about 120 meters lower than today, exposing many areas that are now underwater, some of them massive, like the Sunda land bridge (see map in the Indonesia area), many islands would be connected to the continents, like Tasmania to Australia and Sirilanka to India.&#xA;England would be connected to Europe and the Persian gulf would be dry, as well as the Yellow sea. New Zealand would be just one big island, and hundreds of islands that are now underwater would poke the oceans.&#xA;Using &lt;a href=&quot;https://www.ngdc.noaa.gov/mgg/global/global.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ETOPO1&lt;/a&gt; I've put together a fairly high resolution image of the world showing all the land that would be exposed if the sea level today drops 120m (as it did on the last ice age). You can &lt;a href=&quot;https://easyzoom.com/image/107761&quot; rel=&quot;nofollow noreferrer&quot;&gt;see it here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, the Pacific and the Atlantic would be completely isolated from each other for navigation proposes, as the Magellan strait and Drake passage would be blocked by ice and the Panama canal would be a nearly impossible feat, with the sea level ~120 m lower than today. So probably, train transport would be much more important to carry goods across the Americas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Suez canal would not exist either, and navigation around the Good hope cape at the southern tip of Africa would be constantly threatened and perhaps blocked by icebergs, so most transport between the Indian and Atlantic ocean would be by land too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sea ice would be in contact with the tropical gyros, meaning that massive floating ice islands would be seen even at the Ecuador, and icebergs would be all around the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All that would mean that all the empires that rose from naval power (England, Portugal, Spain) would might not existed, then, maybe Asian powers would rule the world undisputed, and the colonization/invasion of many territories would have never happen or at least would have been delayed, leading to a completely different world distribution and organization.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another interesting change, would be the scarcity of shallow seas compared to today. The &lt;a href=&quot;https://www.ngdc.noaa.gov/mgg/image/fig2_100m_curve.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;drop in total surface area for a given elevation below current sea level becomes stepper once the sea level drops more than 60 m&lt;/a&gt;. Therefore, the sea depth would increase quicker as you go seaward from an &quot;ice age seashore&quot;. This would lead also to a drop in coastal water productivity (opposite to what is believed to have happened in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cretaceous&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cretaceous, with high sea level and abundant shallow seas&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also the &lt;a href=&quot;https://www.scientificamerican.com/article/earth-rotation-summer-solstice/&quot; rel=&quot;nofollow noreferrer&quot;&gt;day would be about one and a half minutes longer&lt;/a&gt;, meaning that the year would have only 364 days.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The change in day length would lead to calendar changes. Currently, a year have 365.2422 days, that is approximated in our calendar to 365.2425, with the fraction part divided as&lt;/p&gt;&#xA;&#xA;&lt;p&gt;0.2425 = 0.25-0.01+0.0025&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The +0.25 is compensated by adding one day every four years, that is a leap year&lt;/li&gt;&#xA;&lt;li&gt;The -0.01 is compensated by skipping one leap year every 100 years&lt;/li&gt;&#xA;&lt;li&gt;And the +0.0025 is compensated by not skipping one leap year every 400 years.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;That's how our calendar works today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, if we assume that the figure of a day 1.5 minutes longer is precise, one year would have 364.8621 days, and the fractional part would probably be approximated to 0.8620, and perhaps divided as&lt;/p&gt;&#xA;&#xA;&lt;p&gt;0.8620 = 0.80 + 0.05 +0.02 -0.0080&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the calendar rule would perhaps be like&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;+0.80 compensated by adding one day every year except every 5 years&lt;/li&gt;&#xA;&lt;li&gt;+0.05 compensated by skipping the above rule exception every 20 years and add a day anyways&lt;/li&gt;&#xA;&lt;li&gt;+0.02 compensated by skipping the exception to the first rule once more every 50 years.&lt;/li&gt;&#xA;&lt;li&gt;-0.0080 compensated by not adding an extra day every 125 years&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Or something like that, many other arrangements could be imagined. But at the end, a typical year would still have 365 days, but the leap years would have one day less instead of one extra day.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="6" LastEditDate="2020-05-10T08:15:01.763" LastActivityDate="2020-05-10T08:15:01.763" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="13176" PostTypeId="1" AcceptedAnswerId="13183" CreationDate="2018-01-25T00:26:35.050" Score="2" ViewCount="465" Body="&lt;h2&gt;Description&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Carbon ($C$), makes up for the majority of our planet and everything that lives on it. Coal, gems &lt;em&gt;(any gem)&lt;/em&gt;, plants, and most sedimentary rocks also contain great deals of carbon.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Fun fact:&lt;/strong&gt; Coal is almost purely carbon; due to it being made entirely of decayed plants and animals.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;h2&gt;Question&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;I'd prefer a fraction or percentage answer &lt;em&gt;(ex. about 1/3 or 34%)&lt;/em&gt; Rounded, if you would.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;&lt;em&gt;About how much of planet Earth is carbon based?&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Proportion of $C$ to really anything else.&lt;/p&gt;&#xA;" OwnerUserId="12057" LastEditorUserId="12057" LastEditDate="2018-02-08T21:57:47.733" LastActivityDate="2018-02-08T21:57:47.733" Title="How much of Earth is carbon-based?" Tags="|geology|" AnswerCount="1" CommentCount="6" ClosedDate="2018-01-25T16:48:16.107" ContentLicense="CC BY-SA 3.0" />
  <row Id="13177" PostTypeId="2" ParentId="13167" CreationDate="2018-01-25T02:02:24.717" Score="2" Body="&lt;p&gt;The top expression is basically the depth-averaged velocity. Meanwhile the second expression only applies to geostrophic flows. The depth-averaged velocity can be caused by many mechanisms, with the geostrophic balance being one of them. The most common ones are the wind and the tides (but also differences in atmospheric pressure, sloping bottoms, ...). Both tides and wind create a barotropic pressure gradient that has to be compensated by other forces in the Navier-Stokes equations, with friction being the most common one. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Geostrophic_current&quot; rel=&quot;nofollow noreferrer&quot;&gt;geostrophic balance&lt;/a&gt; is a specific solution of the NS equations that neglects the effects of friction and any other forces. &lt;a href=&quot;https://marine.rutgers.edu/dmcs/ms501/2004/Notes/Wilkin20041104.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;John Wilkin (Rutgers)&lt;/a&gt; has some good notes on how to estimate these currents from observations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The barotropic pressure gradient is also the integral result for the entire water column. A good illustration is the &lt;a href=&quot;http://en.wikipedia.org/wiki/Thermal_wind&quot; rel=&quot;nofollow noreferrer&quot;&gt;thermal wind&lt;/a&gt; example:  You need a difference in slope between isobaric (pressure) and isopycnal (density) surfaces to give you a baroclinic gradient. In theory in a &lt;a href=&quot;http://en.wikipedia.org/wiki/Barotropic_fluid&quot; rel=&quot;nofollow noreferrer&quot;&gt;barotropic fluid&lt;/a&gt; the flow is the same at all depths: $u(z)=u_{bt}$. Clearly, in practice, any fluid will have boundary layers in which that is not the case. &lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2018-01-26T15:13:55.047" LastActivityDate="2018-01-26T15:13:55.047" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13183" PostTypeId="2" ParentId="13176" CreationDate="2018-01-25T05:06:39.933" Score="5" Body="&lt;p&gt;&lt;strong&gt;0.07%&lt;/strong&gt; of the mass of the Earth is estimated to correspond to carbon atoms (computed from data on &lt;a href=&quot;https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements#Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Abundance of the chemical elements&lt;/a&gt; that comes originally from &lt;a href=&quot;https://web.archive.org/web/20110928074153/http://quake.mit.edu/hilstgroup/CoreMantle/EarthCompo.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; paper)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following table is from the above link and show the relative abundances on Earth in parts per million of mass:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/nbsyE.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nbsyE.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The original table in the source &lt;a href=&quot;https://web.archive.org/web/20110928074153/http://quake.mit.edu/hilstgroup/CoreMantle/EarthCompo.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt; (which correspond to Chapter 1 in, EARTHQUAKE THERMODYNAMICS AND PHASE TRANSFORMATIONS IN THE EARTH'S INTERIOR) is this one:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/oEzxU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oEzxU.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-01-25T16:28:01.347" LastActivityDate="2018-01-25T16:28:01.347" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13185" PostTypeId="1" CreationDate="2018-01-25T13:27:12.940" Score="5" ViewCount="701" Body="&lt;p&gt;I am a beginner in geology and earthquake studies, and learning about subduction zones recently.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Question is: do large earthquakes (sometimes referred to as megathrust quakes) occur on any point in the Subduction zone? For example, the Indo-Australian plate subducts underneath the Burma microplate, and the Sunda plate. So does the megathrust quake occur anywhere along this zone or is it limited to certain areas within the subduction zone?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another related one is what is the different b/w earth quake and rupture process that happens after an earth quake. Example: in some articles about the 2004 Northern-Sumatra quake, I read that &quot;the rupture continued northward for nearly 1000 km&quot;.&lt;/p&gt;&#xA;" OwnerUserId="12066" LastEditorUserId="11908" LastEditDate="2019-04-06T20:05:21.683" LastActivityDate="2019-04-06T20:05:21.683" Title="Megathrust earthquakes on subduction zones" Tags="|geology|geophysics|earthquakes|structural-geology|subduction|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13186" PostTypeId="1" CreationDate="2018-01-25T13:27:29.417" Score="1" ViewCount="419" Body="&lt;p&gt;How eluvial process determines the colour of E horizon lighter compared to O horizon?  &lt;/p&gt;&#xA;" OwnerUserId="12067" LastEditorUserId="6465" LastEditDate="2018-01-26T16:24:13.960" LastActivityDate="2018-01-26T16:24:13.960" Title="How eluvial process determines the difference in colour of soil layers" Tags="|soil|soil-science|" AnswerCount="0" CommentCount="4" ClosedDate="2018-01-26T00:35:04.520" ContentLicense="CC BY-SA 3.0" />
  <row Id="13190" PostTypeId="2" ParentId="13185" CreationDate="2018-01-25T19:03:43.393" Score="5" Body="&lt;p&gt;Yes, mega thrust earthquake can occur in any point of any subduction zone. However, some areas areas are much more active than others, meaning that the frequency of earthquakes and energy released per event will vary largely from place to place. Convergence rate is one important controlling factor for that, but not the only.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding the difference between the earthquake and the rupture process, they are two aspects of the same phenomena. I think your confusion arise by the fact that the location associated to the earthquake (most commonly the &lt;a href=&quot;https://en.wikipedia.org/wiki/Epicenter&quot; rel=&quot;noreferrer&quot;&gt;epicenter&lt;/a&gt;) is associated to the initiation point of the rupture process. However, the energy released by the earthquake and therefore its magnitude is computed from all the energy released along the whole rupture (area of the fault that displaced).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Summarising, the earthquake itself is the whole rupture, but the reported location is the one of the initiation point of the rupture.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-01-25T19:03:43.393" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13191" PostTypeId="2" ParentId="13185" CreationDate="2018-01-25T20:21:04.410" Score="7" Body="&lt;p&gt;Megathrust is not a particularly well defined term but in my experience it generally refers to very large earthquakes that occur on the subduction interface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The subduction interface is the main surface which separates the overriding plate from the subducting plate and is where most of the convergence is accomodated. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0pfeT.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0pfeT.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;(&lt;a href=&quot;http://diss.rm.ingv.it/diss/images/SubductionScheme.png&quot; rel=&quot;noreferrer&quot;&gt;image source&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earthquakes occur on the subduction interface when the two plates are locked together (referred to as strong coupling) and cannot move past each other, leading to accumulation of strain which is eventually released in an earthquake. The amount of coupling on the subduction interface can vary strongly along its length. &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2007JB004981/abstract?&quot; rel=&quot;noreferrer&quot;&gt;Chlieh et al., 2008&lt;/a&gt; says this about the Sumatran megathrust:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Near the equator, the megathrust is locked over a narrow width of only a few tens of kilometers. In contrast, the locked fault zone is up to about 175 km wide in areas where great interplate earthquakes have occurred in the past.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Some subduction interfaces are thought to be almost entirely decoupled and do not generate megathrust earthquakes but large earthquakes can still occur on splay faults in the accretionary prism (&lt;a href=&quot;https://www.nature.com/articles/ngeo151&quot; rel=&quot;noreferrer&quot;&gt;Shaw et al., 2008&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regards to the second part of the question, earthquakes are seismic waves generated by rupturing of rocks in response to accumulated stress. Every earthquake creates a rupture patch with a certain area. The 2004 Sumatra earthquake had a rupture patch that was over 1300 km long which is enormous, hence why it had a such a large magnitude. The rupture started at the southern end of the fault and propagated northwards at 2-3 km/s, taking around 9 minutes to fully rupture. The epicentre is the location of the initial rupture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The seismic moment of an earthquake ($\mathrm{M_0}$ is related to the area of the rupture patch ($\mathrm{A}$), the average displacement on the fault ($\mathrm{D}$) and the friction coefficient on the fault plane ($\mu$) by: $$\mathrm{M_0 = \mu A D}$$&lt;/p&gt;&#xA;" OwnerUserId="2570" LastEditorUserId="2570" LastEditDate="2018-01-25T20:43:19.707" LastActivityDate="2018-01-25T20:43:19.707" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13193" PostTypeId="1" CreationDate="2018-01-25T21:49:36.570" Score="1" ViewCount="145" Body="&lt;p&gt;If one took a slice of the Earth's inner core measuring nine inches across how much would that slice weigh? Or, conversely, how much mass would that contain?&lt;/p&gt;&#xA;" OwnerUserId="12070" LastEditorUserId="94" LastEditDate="2018-01-25T22:21:03.583" LastActivityDate="2018-01-26T09:42:08.853" Title="How much would a nine inch slice of the Earth's inner core weigh?" Tags="|geophysics|core|" AnswerCount="1" CommentCount="2" FavoriteCount="0" ClosedDate="2018-01-27T12:23:50.990" ContentLicense="CC BY-SA 3.0" />
  <row Id="13194" PostTypeId="2" ParentId="13193" CreationDate="2018-01-25T22:04:46.863" Score="4" Body="&lt;p&gt;An oddly specific question, but quite straightforward to calculate. Let's start by calculating the volume of your slice. I'm taking values for the inner core's physical characteristics from &lt;a href=&quot;https://en.wikipedia.org/wiki/Structure_of_the_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;this Wikipedia page&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;9 inches is ~0.229 m.&lt;br&gt;&#xA;Radius of inner core: 1.21e6 m&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We'll approximate your slice as a cylinder: even if we imagine the inner core is a textbook sphere down to the centimetre scale, its curvature would be miniscule over such a thin slice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\pi \times  (1.21 \times 10^6)^2 \times 0.229 \approx 1.05 \times 10^{12} \,\,\mathrm{m^3}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the volume of your slice is around a trillion cubic metres -- about one-fifth of a Lake Michigan, if Wikipedia is to be believed. Now we just need to turn this into a mass:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Density of inner core: 12800 kg/m³&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$12800 \times 1.05 \times 10^{12} \approx 1.348 \times 10^{16}\,\,\mathrm{kg}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, roughly 13 trillion metric tonnes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As jamesqf points out in a comment, this calculation just takes an estimated &lt;em&gt;average&lt;/em&gt; density for the inner core, and assumes that this is the constant density throughout. In reality, the density increases with depth. Kennett (1998) gives a model for this density gradient.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/B9tAR.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/B9tAR.gif&quot; alt=&quot;Earth density gradient&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The inner core is represented by the line section on the bottom right, below the horizontal discontinuity. Eyeballing the graph seems to imply a slightly higher average density than the estimate I pulled from Wikipedia (maybe around 1.3e4 kg/m³), varying by roughly 300 kg/m³ from the inner-core boundary to the centre. The Wikipedia estimate (for which they cite Hazeltt et al. (2006), p. 346) is actually 12,600–13,000 kg/m³ (I just took the mean for my calculation), so I suspect that uncertainties in the overall density values would swamp the inaccuracy introduced by my naïve, constant-density simplification. It's likely that a more reliable characterization of inner core density has been published since 2006; finding it and performing the requisite integration is left as an exercise for the reader ;-).&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;James S. Hazlett, Monroe, R. and Wicander, R. (2006). &lt;em&gt;Physical geology: exploring the Earth&lt;/em&gt; (6. ed.). Belmont: Thomson. ISBN 9780495011484.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;B. L. N. Kennett; On the density distribution within the Earth, Geophysical Journal International, Volume 132, Issue 2, 1 February 1998, Pages 374–382, &lt;a href=&quot;https://doi.org/10.1046/j.1365-246x.1998.00451.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1046/j.1365-246x.1998.00451.x&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2018-01-26T09:42:08.853" LastActivityDate="2018-01-26T09:42:08.853" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13198" PostTypeId="2" ParentId="13159" CreationDate="2018-01-26T22:22:11.763" Score="3" Body="&lt;p&gt;You can easily achieve that assuming that there is no sources of water vapour inside, so the absolute humidity (mass of water per volume of air), remains constant. This excerpt from my undergrad tesis will explain the formula for absolute humidity&lt;a href=&quot;https://i.stack.imgur.com/YOFyA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YOFyA.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once you know the absolute humidity, you can adapt the same formula to calculate the relative humidity of a parcel of outside air (of now known content of water), that is taken from outside to inside a building where its temperature risen to a new value. If we add subscripts &quot;e&quot; to exterior temperature and relative humidity and &quot;i&quot; for interior ones. Most of the constants can be dropped and the interior relative humidity would be given by&#xA;&lt;a href=&quot;https://i.stack.imgur.com/XEQzF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XEQzF.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-01-27T16:37:32.917" LastActivityDate="2018-01-27T16:37:32.917" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13199" PostTypeId="1" CreationDate="2018-01-27T07:46:26.960" Score="5" ViewCount="1316" Body="&lt;p&gt;I've seen papers use oxidation and dissolution of pyrite. Are these two processes the same? I was always under the impression that pyrite does not dissolve easily. What is the difference between oxidation and dissolution of pyrite? &lt;/p&gt;&#xA;" OwnerUserId="11471" LastActivityDate="2018-01-28T09:23:13.300" Title="Difference between pyrite oxidation and dissolution" Tags="|geochemistry|mineralogy|minerals|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13200" PostTypeId="1" AcceptedAnswerId="13204" CreationDate="2018-01-27T19:07:43.790" Score="6" ViewCount="6066" Body="&lt;p&gt;In &lt;a href=&quot;https://hypertextbook.com/facts/2008/VernonWu.shtml&quot; rel=&quot;noreferrer&quot;&gt;this resource&lt;/a&gt;, it says that the average amount of precipitation falling on the Earth per year is approximately 100 cm.  Integrated across the surface of the Earth, that yields approximately 5.1 × 10&lt;sup&gt;14&lt;/sup&gt; m&lt;sup&gt;3&lt;/sup&gt; of water volume that falls to earth. However, it does not give an estimate of how much of that precipitation is specifically rain. So, how much rain falls on the Earth each year?&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="5594" LastEditDate="2018-01-27T19:58:25.700" LastActivityDate="2020-06-30T06:16:15.143" Title="How much rain falls on the Earth each year?" Tags="|meteorology|precipitation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13201" PostTypeId="1" CreationDate="2018-01-27T21:06:38.960" Score="12" ViewCount="879" Body="&lt;p&gt;Sorry in advance if this is too broad a question. Feel free to let me know if it is off-topic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know more than the next person around about climate change, but I am really not a climato-skeptic myself. Yet, I feel uneasy about the way the media reports about the relationship between natural disaster and climate change, and I am looking for an unbiased assessment of these reports.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At least in what some would describe as “mainstream” media, my impression is that the following pattern emerges:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;When a natural disaster or nasty weather seems &quot;intuitively&quot; relatable to global warming (e.g., hurricanes, floods, etc., which a lay person like myself could believe would become more common with global warming), journalists go out of their way to find an expert who will tell them &quot;yes, this is going to be more likely to happen as the planet warms up&quot; and then headline things like &quot;Flooding in Paris Maybe Due To Climate Change&quot;, to only cite the latest ( &lt;a href=&quot;https://www.cbsnews.com/live/video/20180127140626-flooding-in-paris-maybe-due-to-climate-change/?ftag=CNM15cf32c&quot; rel=&quot;noreferrer&quot;&gt;https://www.cbsnews.com/live/video/20180127140626-flooding-in-paris-maybe-due-to-climate-change/?ftag=CNM15cf32c&lt;/a&gt;).&lt;/li&gt;&#xA;&lt;li&gt;On the other hand, when a natural disaster or nasty weather seems to &quot;intuitively&quot; contradict global warming (e.g., snowstorms, cold-wave, etc., which a lay person like myself has a harder time understanding how the phenomenon would become more common with global warming), journalists go out of their way to find an expert who will tell them &quot;this really is consistent with global warming and does not debunk the predictions of climate models at all&quot; and then headline things like &quot;Why the winter cold snap doesn’t disprove climate change” to only cite the latest (this is the title under which an article once appeared on CBS, before the title seem to have changed to &lt;a href=&quot;https://www.cbsnews.com/news/adam-sobel-president-trump-global-warming-tweet-climate-change/&quot; rel=&quot;noreferrer&quot;&gt;https://www.cbsnews.com/news/adam-sobel-president-trump-global-warming-tweet-climate-change/&lt;/a&gt;).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I am not interested in these two examples &lt;em&gt;per se&lt;/em&gt;. In particular, I am not claiming these specific reports are biased (or unbiased for that matter, I am simply not qualified to make that call).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rather, my question is: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;On average, is the media doing a fair and balanced job as an educator of under-informed people (like myself) on that topic?&lt;/li&gt;&#xA;&lt;li&gt;Are they providing an even and science-based account of the relationship between natural disaster and global warming, honestly explaining how global warming is a complex phenomenon which may have surprisingly different --- and sometimes maybe “counter-intuitive” for lay people --- impacts here and there (including cooling and increased likelihood of sever weather in some areas)? &lt;/li&gt;&#xA;&lt;li&gt;Or are they inflating reports “in favor of” action against climate change (e.g., reports that natural disasters will be more frequent with climate change, and that some “counter-intuitive” event do not disprove climate change), while maybe minimizing other reports of situations in which climate change could impact some areas in ways that some would view as “positive”?&lt;/li&gt;&#xA;&lt;li&gt;Following useful comments: if &quot;averaging&quot; makes the question too hard to answer, which media does a good job, and which doesn't? &lt;/li&gt;&#xA;&lt;li&gt;Any empirical work done on that question? Did anyone try to text-mine information websites and assess biases (compared to the best scientific evidence) in the media’s presentation of the relationship between natural disaster and global warming?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="7904" LastEditorUserId="7904" LastEditDate="2018-01-28T00:15:07.697" LastActivityDate="2018-01-28T18:47:42.223" Title="Relationship between natural disaster and global warming, in the media" Tags="|climate-change|natural-disasters|extreme-weather|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13203" PostTypeId="2" ParentId="13201" CreationDate="2018-01-28T01:41:03.527" Score="8" Body="&lt;p&gt;First thing first: It is very hard, if not impossible, to attribute a single anomalous weather event to climate change. The weather exhibits a huge amount of natural variation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The recent spate of cold weather that recently has hit the eastern part of North America is consistent with climate change and has even predicted to be a consequence of climate change. However, this spate of cold weather is also completely consistent with natural variations in the weather. As noted above, it's very hard to attribute a single weather anomaly to climate change. Winter weather is, by its nature, extremely variable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's also important to remember that this cold weather is a local event. Europe and Asia have been quite balmy this winter. Do not be surprised if December and January turn out to be considerably warmer than historical values when averaged over the entered planet. And even if it isn't, that does not falsify climate change. Climate change is about what happens after removing short term variations (&quot;years&quot; is short term) from the equation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that I have been consistently using the term climate change rather than global warming. It's not that global warming is an incorrect term. People mistakenly take global warming to mean that every single day will be warmer than it was a year ago, everywhere on the planet. The science does not say this. As noted above, the recent spate of cold weather that has plagued and continues to plague eastern North America is completely consistent with and has been predicted by climate change (or global warming, if you will). But it's also consistent with natural variations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, at least one event during the last year most likely was amplified by climate change, and that would be the huge amount of water dumped on southeast Texas by Hurricane Harvey. Tropical cyclones (e.g. hurricanes) and even very strong ones, are natural occurrences. Climate change does not predict that we will get more tropical cyclones. It does however predict that they will get more severe as the Earth warms up, on average. The huge amounts of water dumped by Harvey are consistent with and predicted by climate change, but not so much consistent with natural variations. While Harvey itself wasn't caused by climate change, a sizable portion of the 52 inches of the rain that it dumped most likely was a result of climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;&lt;strong&gt;Update, since I didn't directly address the questions raised&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One reason I didn't address those questions is because the original post has too many questions (Martin: Please read up on how to write a good stackexchange question.) I'll focus on a couple of them.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;On average, is the media doing a fair and balanced job as an educator of under-informed people (like myself) on that topic?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The first of the cited reports in the question has the teaser headline &quot;Flooding in Paris Maybe Due To Climate Change&quot; -- but the link does not discuss that at all. The news report merely covers the fact that Paris is currently flooding. (Perhaps a once longer version did cover a potential link to climate change.) This is a disservice because &lt;a href=&quot;https://wwa.climatecentral.org/analyses/european-rainstorms-may-2016/&quot; rel=&quot;noreferrer&quot;&gt;a potential link between flooding in Paris and climate change does exist&lt;/a&gt;. In particular, climate change has roughly doubled the probability of severe flooding events in Paris.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second cited article is much better. It does not attribute the late December / early January cold snap in the US to climate change. It merely states facts. One fact is that many people (including the president of the US) see a cold snap as falsifying climate change. Another fact is that this is not the case. Climate change, aka global warming, does not say that winter will vanish. (Okay, some alarmists do say that. You need to ignore them, along with the deniers.) The natural variations in winter weather in temperate climates is huge. Climate change has not overcome these huge swings. We will continue to see cold snaps. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Are they providing an even and science-based account of the relationship between natural disaster and global warming, honestly explaining how global warming is a complex phenomenon which may have surprisingly different --- and sometimes maybe “counter-intuitive” for lay people --- impacts here and there (including cooling and increased likelihood of sever weather in some areas)?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This depends very much on where one gets ones news on climate change issues. Fox News? The odds are against it. &lt;a href=&quot;https://www.ucsusa.org/global-warming/solutions/fight-misinformation/cable-news-coverage-climate-change-science.html&quot; rel=&quot;noreferrer&quot;&gt;According to one study&lt;/a&gt;, 72% of Fox News's reporting on climate change was inaccurate or downright false, with the inaccuracies veering toward denialism. This same study found MSNBC to do a much better job, with only 8% of its reporting on climate change being inaccurate or downright false (with the inaccuracies here being mostly overly alarmist).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, an 8% error rate is nothing to write home about, and the superficial nature of the reporting is even less to write home about. The news media is not where you should go if you want good reporting on climate change, or on science and technology in general. I have a rather low regard for news media journalism regarding science and technology. The reporting is rather awful. Keep in mind: Journalists in general avoided STEM classes from the ninth grade and up, and when they couldn't, they took classes like &lt;em&gt;Physics for Poets&lt;/em&gt;.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2018-01-28T18:47:42.223" LastActivityDate="2018-01-28T18:47:42.223" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13204" PostTypeId="2" ParentId="13200" CreationDate="2018-01-28T02:42:21.107" Score="6" Body="&lt;p&gt;That's a tricky question, it will vary from year to year but we can narrow it down with some assumptions so I can give an answer. The assumptions will be:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;All precipitation over the sea will become liquid in contact with the sea surface and will be considered as rain.&lt;/li&gt;&#xA;&lt;li&gt;Precipitation over Antarctica is negligible at a global scale.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The second one is pretty reasonable: look at the global distribution of precipitation on the era of satellite data (&lt;a href=&quot;https://link.springer.com/article/10.1007/s10712-017-9416-4&quot; rel=&quot;noreferrer&quot;&gt;reference&lt;/a&gt;).&#xA;&lt;a href=&quot;https://i.stack.imgur.com/YrxH7.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YrxH7.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With these assumptions we only need to compute the amount of solid precipitation on land (outside Antarctica) and subtract it from the global total. And we can do so using the data provided by the &lt;a href=&quot;https://kunden.dwd.de/GPCC/Visualizer&quot; rel=&quot;noreferrer&quot;&gt;Global Precipitation Climatology Centre&lt;/a&gt;, which provide both the global mean precipitation on land:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/cYjV6.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cYjV6.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And the fraction of liquid precipitation on land:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/XWWGs.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XWWGs.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've downloaded both datasets in ASCII format, and computed that the mean percentage of liquid precipitation is 74.1%, but we can't use that value, because it might be strongly affected by areas with little precipitation. So if we compute a cell by cell total SOLID precipitation per year, and multiply that for the surface of a 1°x 1° cell (considering the effects of latitude), we get a total of solid precipitation for 2016 of 1.5e13 m³.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So with the additional assumption that 2016 was a representative year. &lt;strong&gt;That will take your total precipitation of 5.1e14 m³ per year to 5.0e14 m³ per year of RAIN only.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Perhaps we should have expected that there is not much of a difference given that most of the rainfall happen on the sea (The total precipitation on land for 2016 was 1.1e14 m³ meaning that the 13.6% was solid and 86.4% was rain).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now if you want to consider snowfall over the sea, I don't know of a model with such output product. Therefore, you can make a simple model or make some assumptions to use Sea Surface Temperature to figure out if precipitation will turn to rain at some high above the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But again, if you look at the map of global distribution of precipitation, the fraction coming from latitudes at which you could expect sea surface snow is rather small, so the correction coming from snowfall over the sea is likely to be a pretty small one too.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-01-28T03:22:34.617" LastActivityDate="2018-01-28T03:22:34.617" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13205" PostTypeId="1" CreationDate="2018-01-28T03:39:01.440" Score="5" ViewCount="88" Body="&lt;p&gt;This is really a two part question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Is there a good model for mapping climate conditions in a particular location to pleasantness or livability or something like that?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) If there is such a model, has anyone applied this livability index to predictions of future climate changes?  An perhaps created a map?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ideally it would easy to answer questions of the form: would Detroit or San Francisco likely have a more pleasant climate in 2050?&lt;/p&gt;&#xA;" OwnerUserId="12085" LastActivityDate="2022-02-25T17:05:27.020" Title="What regions of the US will have *improved* climate given current predictions of climate change?" Tags="|climate-change|models|human-influence|predictability|global-weirding|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13206" PostTypeId="1" AcceptedAnswerId="13208" CreationDate="2018-01-28T04:00:53.770" Score="6" ViewCount="1292" Body="&lt;p&gt;As I understand it, moisture condenses at mountain tops to form the mountain glaciers that provide water. The mountain topography doesn't change much in the span of a few decades, so if there's more moisture in the atmosphere due to rising global temperatures, then it seems like there should be more water to condense on these mountains. But somehow, there's even less mountain ice, why? &lt;/p&gt;&#xA;" OwnerUserId="12086" LastEditorUserId="11908" LastEditDate="2019-02-03T20:10:23.607" LastActivityDate="2019-02-03T20:10:23.607" Title="If there's more water in the atmosphere due to global warming, how are there fewer mountain glaciers?" Tags="|climate-change|glaciology|ice|glacier|cryosphere|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13208" PostTypeId="2" ParentId="13206" CreationDate="2018-01-28T04:47:49.497" Score="17" Body="&lt;p&gt;Indeed some glaciers are growing and gaining mass due to increased precipitation (in part due to climate change and enhanced atmospheric water content). But that's the case only for glaciers in very cold places, like East Antarctica, where most glaciers appear to be growing at increasing rates (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1002/2017GL072937/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;,&lt;a href=&quot;https://phys.org/news/2017-05-growth-east-antarctic-ice-sheet.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;). But unfortunately West Antarctica is pretty much a desert; the total precipitation on average is less than in the Sahara Desert. That is usually the case in very cold places. The capacity of air to hold dissolved water decreases exponentially at lower temperatures. Therefore cold glaciers (the ones that are most often growing) account for a small amount of the total global ice mass change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In contrast, temperate glaciers (i.e. not so cold) constitute the majority of the most well known mountain glaciers (outside Antarctica and the High Arctic). These in many cases are receiving more precipitation, but the increases in accumulation are in most cases offset by the increase in temperature, which have a double impact:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;More melting due to higher temperatures&lt;/li&gt;&#xA;&lt;li&gt;A larger fraction of the precipitation falls as rain instead of snow, therefore promoting melting instead of accumulation.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;That last point is not that intuitive, but as explained in &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13442/how-does-temperature-impact-the-elevation-distribution-of-orographic-precipitati&quot;&gt;this question and answer&lt;/a&gt;, warmer air carrying more moisture will develop water droplets quicker, therefore dropping most of the extra moisture at lower elevations. As a consequence, the rain-driven melt in the lower areas of the glacier will overcome the a moderate increase in the accumulation at higher elevations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, there is a positive feedback kicking in against the glaciers: The more the glacier melts, the lower its surface will be, therefore it will be exposed to warmer temperatures leading to further melting, leading to more surface lowering, exposing it to even higher temperatures, producing even more melting and so on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is also important to note that glaciers grow due to snow accumulation. It is unclear to me if that's what you meant by &quot;moisture condenses at mountain tops&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, it worth noting that glaciers have been receding since the last ice age about 20,000 years ago (as we have learned from &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0277379101001019&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oxygen isotopes on foraminifera deposits&lt;/a&gt; and &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S027737911630364X&quot; rel=&quot;nofollow noreferrer&quot;&gt;glacier deposits&lt;/a&gt;), the recession slowed down the last ~6,000 years slowly approaching to a steady state. However, recent warming has just accelerated the process a bit, enhancing the extent and speed of the natural deglaciation, but we have to acknowledge that the glaciers were already out of balance and shrinking way before the industrial revolution.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-12T22:26:00.317" LastActivityDate="2018-03-12T22:26:00.317" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="13210" PostTypeId="2" ParentId="13199" CreationDate="2018-01-28T09:23:13.300" Score="4" Body="&lt;p&gt;Oxidation and dissolution are not the same processes, but they are related when discussing the breakdown of pyrite in near surface environments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Dissolution is a process(*1) in which the chemical components of a solid become part of a liquid, in the liquid state. For example, take fresh water and salt. Now dissolve the salt in the fresh water. Instead of having NaCl and H&lt;sub&gt;2&lt;/sub&gt;O, you now have H&lt;sub&gt;2&lt;/sub&gt;O with Na&lt;sup&gt;+&lt;/sup&gt; and Cl&lt;sup&gt;-&lt;/sup&gt; ions floating in it, not solid anymore. This is not something happens easily with pyrite. You can't just dump FeS2 in water and expect to have Fe&lt;sup&gt;2+&lt;/sup&gt; and S&lt;sup&gt;(2)-&lt;/sup&gt; in the water. This is because the sulfur is in the reduced state, as &lt;em&gt;sulfide&lt;/em&gt;. The more soluble form of sulfur is &lt;em&gt;sulfate&lt;/em&gt;, the oxidised form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oxidation is a process in which a compound or element bonds with (more) oxygen(*2). In order to dissolve pyrite, you have to convert the insoluble sulfide to soluble sulfate. In your &lt;a href=&quot;https://earthscience.stackexchange.com/q/13091/725&quot;&gt;previous question&lt;/a&gt; you noted the oxidation reaction for pyrite:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\ce{FeS2(s) + 15/4 O2(aq) + 7/2 H2O → Fe(OH)3(s) + 4H+(aq) + 2SO4^2-(aq)}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You start with pyrite in the solid form, and you end up with sulfate (sulfur bonded to four oxygens). The leftover iron is deposited as insoluble iron oxides and hydroxides (basically - rust), and you're also generating a bunch of protons that make everything acidic (i.e. acid mine drainage).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*1 - strictly speaking, dissolution doesn't have to be a solid in a liquid. It can be anything in anything.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*2 - actually oxidation is an electron transfer reaction and can occur with no oxygen involved at all.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-01-28T09:23:13.300" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13212" PostTypeId="1" AcceptedAnswerId="13222" CreationDate="2018-01-28T16:53:01.583" Score="6" ViewCount="1433" Body="&lt;p&gt;I recently joined a geophysics project to assist with some of their machine learning modeling but am trying to gather the domain knowledge required to participate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Something I don't quite understand is the common-midpoint stack, Normal MoveOut &amp;amp; raw data. I have these seg-y files and I am able to plot them in python. They look fine to me, but I am reading a lot about CMP stacking, weighted CMP stacking and NMO. Are seg-y files considered to be &quot;raw seismic data&quot;. Is the CMP and NMO process something that happens at the stage I am getting the files? I am confused because these seem to be standard practices yet I am unable to find an implementation for any of this in any programming language. Are there any tools you recommend for preparing seismic data for machine learning modeling? &lt;/p&gt;&#xA;" OwnerUserId="12092" LastEditorUserId="543" LastEditDate="2021-10-06T06:10:37.103" LastActivityDate="2021-10-06T06:10:37.103" Title="What is the relationship between raw seismic data, CMP Stacking, NMO &amp; Machine Learning" Tags="|geophysics|seismology|seismic|data-formats|machine-learning|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13213" PostTypeId="2" ParentId="13201" CreationDate="2018-01-28T17:04:27.250" Score="1" Body="&lt;p&gt;a warming planet makes storms worse in two ways. The most straightforward comes when you realize storms are driven by differences in temprature and pressure between different parts of the atmosphere, climate change does not worm all parts of the atmosphere equally leading to greater variability in temprature, by warming the ocean this difference becomes even more extreme making the storm itself more powerful. Now to be fair there may be counter forces in wind shear but this is even harder to predict and would still not stop the worst storms, so we may end up with fewer storms overall but with the ones we do have being far worse. &lt;a href=&quot;http://science.sciencemag.org/content/327/5964/454.full?ijkey=PFX.MzpFJDznM&amp;amp;keytype=ref&amp;amp;siteid=sci&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://science.sciencemag.org/content/327/5964/454.full?ijkey=PFX.MzpFJDznM&amp;amp;keytype=ref&amp;amp;siteid=sci&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Warmer air and water also increase evaporation giving the storms more precipitation to throw around, this is also how it makes snow storms worse, there is more moisture available. Another big effect is rising sea level It is easy to see how this makes storm flooding worse, if the water level is higher it takes less of a rise to get flooding and the same amount of rise results in worse flooding. &lt;a href=&quot;http://www.nature.com/news/2008/080903/full/news.2008.1079.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.nature.com/news/2008/080903/full/news.2008.1079.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2018-01-28T17:04:27.250" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13215" PostTypeId="1" CreationDate="2018-01-28T18:39:51.947" Score="1" ViewCount="529" Body="&lt;p&gt;Why Divergent boundary create ridges between oceanic plates and rift valley between continental plates? I think that the ridges are formed because of the volcanic eruptions. But like rift valley in case of continental plates, can trench ever form because of the divergent oceanic plates?&lt;/p&gt;&#xA;" OwnerUserId="12045" LastEditorUserId="2570" LastEditDate="2018-01-28T21:27:30.147" LastActivityDate="2018-01-28T21:27:30.147" Title="Divergent boundary and trenches between oceanic plates" Tags="|plate-tectonics|continental-rifting|ocean-ridge|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13216" PostTypeId="1" AcceptedAnswerId="13220" CreationDate="2018-01-28T19:52:00.920" Score="0" ViewCount="356" Body="&lt;p&gt;Have they always been here since the river was formed?  Are some newer than others?  &lt;/p&gt;&#xA;" OwnerUserId="12094" LastEditorUserId="12094" LastEditDate="2018-01-28T23:56:19.690" LastActivityDate="2018-01-28T23:56:19.690" Title="Where do riverbed stones come from?" Tags="|geology|" AnswerCount="1" CommentCount="2" ClosedDate="2018-01-29T14:34:24.837" ContentLicense="CC BY-SA 3.0" />
  <row Id="13217" PostTypeId="1" CreationDate="2018-01-28T19:56:23.787" Score="12" ViewCount="10150" Body="&lt;p&gt;I am confused after reading conflicting text from different sources. For example, I read that divergent oceanic plates form ridges. &lt;a href=&quot;https://www.youtube.com/watch?v=Wq9kLzm36h0&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Geographic&lt;/a&gt; calls Mid-Atlantic Ridge a valley!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, &lt;a href=&quot;https://en.wikipedia.org/wiki/Mid-Atlantic_Ridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; states this:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Mid-Atlantic Ridge includes a deep rift valley that runs along the axis of the ridge along nearly its entire length. This rift marks the actual boundary between adjacent tectonic plates, where magma from the mantle reaches the seafloor, erupting as lava and producing new crustal material for the plates.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As per &lt;a href=&quot;https://en.wikipedia.org/wiki/Trench&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;: a rift valley is a type of trench!&lt;/p&gt;&#xA;" OwnerUserId="12045" LastEditorUserId="28050" LastEditDate="2018-03-02T12:50:22.820" LastActivityDate="2021-08-14T00:31:58.540" Title="Is the Mid-Atlantic Ridge a ridge or a trench?" Tags="|plate-tectonics|atlantic|ocean-ridge|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13218" PostTypeId="2" ParentId="13217" CreationDate="2018-01-28T21:08:06.803" Score="20" Body="&lt;p&gt;Trench has a specific meaning in plate tectonics. It doesn't just refer to any valley; it specifically refers to the features formed at subduction zones by the flexure of the downgoing oceanic plate. A classic example is the Marianas Trench which is the location of the deepest point in the ocean&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QI2yh.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QI2yh.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fast spreading ridges do indeed have valleys at their centre but these are not usually referred to as trenches to avoid confusion. In slow spreading ridges the valley is often filled up with erupted lavas. However, the valley sits on top of a much larger ridge, which is the surface expression of hot mantle upwelling below the spreading axis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lA2PQm.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lA2PQm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2018-01-28T21:08:06.803" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13219" PostTypeId="2" ParentId="13215" CreationDate="2018-01-28T21:21:52.627" Score="5" Body="&lt;p&gt;The elevation of oceanic crust is controlled by Pratt &lt;a href=&quot;https://en.wikipedia.org/wiki/Isostasy&quot; rel=&quot;noreferrer&quot;&gt;isostasy&lt;/a&gt;, whereby hotter crust is elevated because it is less dense. Oceanic crust is produced at mid-ocean ridges and cools as it moves away from the ridge. &lt;strong&gt;Mid-ocean ridges are hot and therefore they are elevated above the colder, more dense adjacent crust.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In continental rifts, the dominant process controlling the topography is &lt;a href=&quot;https://en.wikipedia.org/wiki/Extensional_fault&quot; rel=&quot;noreferrer&quot;&gt;normal faulting&lt;/a&gt;, which leads to subsidence of the rift valley floor and uplift of the sides, leading to the formation of mountains either side of the active rift. &lt;strong&gt;Continental rifts form valleys because they have not yet reached isostatic equilbrium and their topography is controlled by extensional faulting.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2018-01-28T21:21:52.627" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13220" PostTypeId="2" ParentId="13216" CreationDate="2018-01-28T23:08:51.553" Score="4" Body="&lt;p&gt;Riverbed 'stones' - I assume you mean things like pebbles, boulders, etc. are pieces of rock that have weathered out and been deposited in the river. Some come from rock that is very close to where they are located and some have been transported from very far away. In general (and it is a very broad generalization) the rounder the stone, the longer it has been in the river and the more likely it is to have come from far away. Of course that depends on the hardness of the rock, and other factors, too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some rocks are newer than others. Some have been formed quite recently and some are billions of years old.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2018-01-28T23:08:51.553" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13221" PostTypeId="1" CreationDate="2018-01-28T23:10:01.787" Score="4" ViewCount="96" Body="&lt;p&gt;I read somewhere that the new &lt;a href=&quot;https://en.m.wikipedia.org/wiki/MOSE_Project&quot; rel=&quot;nofollow noreferrer&quot;&gt;MOSE&lt;/a&gt; system can withstand a maximum rise in water of about 3m. I was wondering if that extreme case will happen on the coast line of Lido di Venezia, there will be a rising of the water with a consequent problem at the many beaches along the litoral. What are they expecting? Venice would be, hopefully, saved while Lido will suffer high level of water on the beaches. And more important: how much above the sea level is the highest point of Lido di Venezia?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Added: if the highest point at Lido is 3m that would be the only dry place in case of a tide of 3m. Or I'm wrong?&lt;/p&gt;&#xA;" OwnerUserId="12097" LastEditorUserId="12097" LastEditDate="2018-01-29T00:08:28.197" LastActivityDate="2018-02-01T18:04:55.797" Title="High tides at Venice" Tags="|tides|coastal|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13222" PostTypeId="2" ParentId="13212" CreationDate="2018-01-29T01:37:53.890" Score="7" Body="&lt;p&gt;SEG-Y files are a general purpose archival format. So they can be &quot;anything&quot;. 2D seismic, 3D seismic, raw, processed, unstacked or even derivatives (seismic attributes).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How to get information about your data in the SEG-Y file:&#xA;SEG-Y contain 3 types of headers that describe the data.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ivPgb.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ivPgb.png&quot; alt=&quot;SEG-Y structure. CC-BY-SA Agile Scientific &quot;&gt;&lt;/a&gt;&#xA;The EBCDIC header is a 40 by 80 character sheet that is a remnant from the times of punchhole cards &lt;a href=&quot;http://the-geophysicist.com/ebcdic-how-punch-cards-helped-me-get-to-know-my-data&quot; rel=&quot;noreferrer&quot;&gt;(I'm not joking)&lt;/a&gt;. Usually it contains info about the state of the seismic. Processing workflow, acquisition geometries etc. The binary header has some more fixed data about the data set. The trace headers contrain every separate data set from the acquisition. Nice blog by Agile Scientific &lt;a href=&quot;https://agilescientific.com/blog/2014/3/26/what-is-seg-y.html&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can read about the details of seismic processing and conventions in the open access book &quot;&lt;a href=&quot;https://wiki.seg.org/wiki/Seismic_Data_Analysis&quot; rel=&quot;noreferrer&quot;&gt;Seismic Data Analysis&lt;/a&gt;&quot;. It used to be several hundred dollars and has been cited in every seismic lecture I have ever attended. However, I'll give you some answers now.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Common Midpoints&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;CMP stacking, weighted CMP and NMO are highly entangled. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BP4o7.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BP4o7.png&quot; alt=&quot;CMP Definition&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A seismic measurement, listens really close to the reflection from the subsurface. However, it's a little noisy. &quot;Stacking&quot; is recording the same place over and over, then adding it up to cancel out random noise and enhance coherent signal. However, just doing it in the same area would be very inefficient, therefore we change the acquisition over the point we illuminate, in the picture you see that we have a nice fan of ray geometries going to the same point in the middle, the Common MidPoint CMP. This leads some interesting behaviour. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Normal Moveout&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VV62j.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VV62j.png&quot; alt=&quot;NMO equation&quot;&gt;&lt;/a&gt; &#xA;this is the formulation to calculate how a record from a different angle can be shifted to be in line with another record for the aforementioned stacking. As you can imagine the records that have longer ray paths take longer, depending on the velocity of the rock they travel through. This shift down-ward is namen Normal MoveOut (NMO). The equation above is an approximation, but it's good enough for this explanation, check out the book for more info on this. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Post-Stack vs. Pre-Stack&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;A seismic acquisition over a 2D area is named 3D seismic, because X-Y-T (recording time). The data, repeated over the same point in X-Y as mentioned above will have several record with the same T and a different &quot;offset&quot; between the source and the receiver. That means, 3D seismic data coming fresh out of the field will be four-dimensional. This is called pre-stack. Once we do a lot of data preconditioning and filtering and a smarter version of the CMP stacking above, we get 3D seismic that is actually three-dimensional.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Stacking versus Migration&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Stacked data will have all kinds of weird wave effects in it. Usually geologists will work on &quot;migrated&quot; data. A migration aims to find the &quot;true&quot; location of a reflector, reversing wave effects. I suspect you might get this one.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Time versus Dpeth&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;You may have wondered from before about X-Y-T. T stands for time not depth, that is because our data is measured in recording time and most geophysicists will work in time. Most likely the migration even is done in time and you get a X-Y-T cube. However, depth-conversion does happen, but it depends on a accurate time-depth relationship. People tend not to trust these too much. Caveat: A depth migration does not have to result in a X-Y-Z cube that you get.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Practical Advice&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;As a practical guide, you may want to start at the EBCDIC header. Was your data processed? Stacked? Migrated? Do you have a T-cube or Z-cube?&#xA;Familiarize yourself with the binary header and a couple trace headers. What are the extents of your data? Etc.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Machine Learning&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Most machine learning is done in proprietary code. The only open source code I know of in seismic deep learning is &lt;a href=&quot;https://github.com/bolgebrygg/MalenoV&quot; rel=&quot;noreferrer&quot;&gt;MalenoV&lt;/a&gt;. However, loading a full 3D seismic into RAM will not always be possible. Loading it into the GPU RAM will seldomly be possible. This is the first place, where you are free to come up with a smart solution.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Bonus&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Here is a list of &lt;a href=&quot;https://en.wikipedia.org/wiki/Comparison_of_free_geophysics_software&quot; rel=&quot;noreferrer&quot;&gt;Free Geophysics Software&lt;/a&gt; and an &lt;a href=&quot;https://github.com/softwareunderground/awesome-open-geoscience/&quot; rel=&quot;noreferrer&quot;&gt;awesome list of open geoscience&lt;/a&gt;. These aren't exhaustive, but a good start.&lt;/p&gt;&#xA;" OwnerUserId="507" LastActivityDate="2018-01-29T01:37:53.890" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13223" PostTypeId="2" ParentId="9050" CreationDate="2018-01-29T05:13:36.990" Score="8" Body="&lt;p&gt;Having the sun directly overhead can happen only between the Cancer and Capricorn tropics. That is, only the places between 23.5° of latitude north and 23.5° of latitude south.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;On the Cancer tropic (23.5° latitude north) it will happen once every year, on the day of the northern hemisphere solstice (about June 21st).&lt;/li&gt;&#xA;&lt;li&gt;On the Capricorn tropic (23.5° latitude south) it will happen once every year, on the day of the southern hemisphere solstice (about December 21st).&lt;/li&gt;&#xA;&lt;li&gt;On the equator it happen twice every year. One on each equinox (about March 21st and September 21st).&lt;/li&gt;&#xA;&lt;li&gt;For any other given place between the tropics, it will also happen twice every year. On the days when the &lt;a href=&quot;https://en.wikipedia.org/wiki/Declination&quot; rel=&quot;noreferrer&quot;&gt;Declination&lt;/a&gt; of the sun (a coordinate in the sky analogous to latitude on the Earth), matches the latitude of the place.  Various formulas to calculate the declination to various precision can be found at &lt;a href=&quot;https://en.wikipedia.org/wiki/Position_of_the_Sun#Declination_of_the_Sun_as_seen_from_Earth&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;This figure would help to visualize the situation:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/RtZBS.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RtZBS.png&quot; alt=&quot;sun_earth_dec21&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The configuration depicted, will happen on the southern hemisphere summer solstice (about December 21st): The only day of the year when the sun passes exactly overhead on the Tropic of Capricorn.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When it comes to what time of the day it will happen, it won't happen at local noon (see &lt;a href=&quot;https://earthscience.stackexchange.com/questions/6920/why-doesnt-the-sun-reach-its-highest-point-overhead-at-exactly-1200-noon/6921#6921&quot;&gt;this question&lt;/a&gt;), the exact time requires a lengthy calculation (see &lt;a href=&quot;https://en.wikipedia.org/wiki/Equation_of_time&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt;), but a good estimate would be:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;GMT - TimeZone + Longitude/15&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where GMT is Greenwich Meridian Time (the same than Universal Time for this effects), TimeZone is the time zone you are at. For instance -7 for the Pacific Time Zone in North America. And Longitude, is the longitude of the observer (expressed as a positive value for East longitudes and a negative value for West ones). The error of this estimate can be in the order of 15-20 minutes.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-01-30T06:58:13.437" LastActivityDate="2018-01-30T06:58:13.437" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="13226" PostTypeId="1" CreationDate="2018-01-29T11:21:59.950" Score="5" ViewCount="181" Body="&lt;p&gt;What is the best method of calculating the number of model grid cells (e.g. of climate models) covering a specific country? For example, if I wanted to know how many 2 degree grid cells are in the United Kingdom, how would I go about it? At present I use the mapping toolbox in matlab and add a 2 degree grid and calculate manually. Is there a better way of doing this? Any advice is appreciated.  &lt;/p&gt;&#xA;" OwnerUserId="4582" LastEditorUserId="11908" LastEditDate="2018-01-30T01:09:43.623" LastActivityDate="2018-01-30T01:09:43.623" Title="Calculate the number of model grid cells covering a specific country" Tags="|models|numerical-modelling|grid-spacing|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13228" PostTypeId="2" ParentId="13226" CreationDate="2018-01-29T15:06:28.883" Score="2" Body="&lt;p&gt;Here is a simple 'back of the napkin' idea for Python:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Get a shapefile of the borders and use Python to create a polygon of the borders.&lt;/li&gt;&#xA;&lt;li&gt;Use mpl_toolkits to convert the climate model to X and Y coordinates&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://stackoverflow.com/questions/36399381/whats-the-fastest-way-of-checking-if-a-point-is-inside-a-polygon-in-python&quot;&gt;Check to see if the model grid points are within the Polygon&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="704" LastActivityDate="2018-01-29T15:06:28.883" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13229" PostTypeId="1" CreationDate="2018-01-29T18:59:23.153" Score="2" ViewCount="1775" Body="&lt;p&gt;Overtime, we've located, drilled, and used a large portion of our planet's &lt;strong&gt;fossil fuels.&lt;/strong&gt; Fossil fuels are found underground, and are dug up to be used as a form of energy, &lt;em&gt;(ex: Oil found by drilling into the ground and extracting it from the surface through a long pipe)&lt;/em&gt; but it's also becoming an issue as to &lt;strong&gt;we might be running out of easily possessable fossil fuel.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I had control over the process of fossil fuel consumption in the entire world, I'd &lt;strong&gt;terminate all fossil fuel extraction until further notice,&lt;/strong&gt; because if people are going to avoid running out of fossil fuels, we are go&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my question is:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Approximately &lt;em&gt;&lt;strong&gt;how long&lt;/strong&gt;&lt;/em&gt; of a wait is it until the majority of extracted fossil fuels are &lt;strong&gt;renewed?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="12057" LastActivityDate="2018-01-29T18:59:23.153" Title="How long does it take for fossil fuels to renew?" Tags="|fossil-fuel|time|" AnswerCount="0" CommentCount="3" ClosedDate="2018-01-29T19:35:32.097" ContentLicense="CC BY-SA 3.0" />
  <row Id="13231" PostTypeId="1" CreationDate="2018-01-29T23:01:44.267" Score="2" ViewCount="652" Body="&lt;p&gt;I read that limestone is made from the compaction of marine animals' bones. But, I am unable to find out why limestone could not have been produced from &lt;a href=&quot;https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth%27s_crust&quot; rel=&quot;nofollow noreferrer&quot;&gt;calcium occurring naturally (5th most abundant element in earth's crust) in the Earth Crust and in the mantle?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is gypsum also produced from marine animal's bones?&lt;/p&gt;&#xA;" OwnerUserId="12045" LastEditorUserId="12045" LastEditDate="2018-01-29T23:13:16.873" LastActivityDate="2018-01-30T00:15:22.030" Title="Inorganic Limestone and Inorganic Gypsum" Tags="|rocks|mineralogy|sedimentology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13232" PostTypeId="2" ParentId="13231" CreationDate="2018-01-30T00:15:22.030" Score="1" Body="&lt;p&gt;Limestone is a sedimentary rock made up mainly of the mineral calcite (calcium carbonate). It may be made up of biogenic calcite such as shells or inorganic calcite deposited as fine grained &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Micrite&quot; rel=&quot;nofollow noreferrer&quot;&gt;micrite&lt;/a&gt;&quot; although some micrite may also have a biological origin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Animals don't have bones made from gypsum so all gypsum deposits have non-biological origin.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2018-01-30T00:15:22.030" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13234" PostTypeId="2" ParentId="13145" CreationDate="2018-01-30T15:39:17.380" Score="1" Body="&lt;p&gt;Light or calm winds do not cause reductions in visibility, but stronger winds will generally be associated with better visibilities. Poor visibility is more likely in a humid, polluted air-mass than a clean dry air-mass. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reductions in ‘visibility’ or visual range are caused by the scattering and absorption of radiation by atmospheric particulates or aerosols. This attenuation of radiation will depend on the type, size and concentration of these particulates or aerosols. In a humid airmass water droplets can form on certain types of aerosols and these droplets can increase in size as humidity increases.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Strong winds will tend to mix the polluted air near the surface with cleaner air aloft. This mixing will also create a more uniform profile of temperature and humidity in the lowest portion of the atmosphere. If there are light winds overnight, the air near the surface becomes cooler and more humid than the air aloft. The pollutants become concentrated in this cool stable layer of air near the surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are exceptions, namely advection or coastal fog. In far north-east of the U.K it’s not that uncommon to see fog with 20-30 mph winds during late spring and early summer.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.metoffice.gov.uk/learning/fog&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.metoffice.gov.uk/learning/fog&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12109" LastActivityDate="2018-01-30T15:39:17.380" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13235" PostTypeId="2" ParentId="13206" CreationDate="2018-01-30T16:54:19.690" Score="2" Body="&lt;p&gt;Mountains are a little unusual in terms of water vapor capture.  &lt;a href=&quot;https://treelinebackpacker.com/2013/05/06/calculate-temperature-change-with-elevation/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Temperature drops with elevation&lt;/a&gt; so some mountains have ice-cover even in summer and/or even in warm latitudes.   Mountain ranges tend to block air-flow and if there's a prevailing wind direction, it's not uncommon for for the other side of the mountain to be desert.   This is called a &lt;a href=&quot;https://www.nationalgeographic.org/encyclopedia/rain-shadow/&quot; rel=&quot;nofollow noreferrer&quot;&gt;rain shadow&lt;/a&gt;.  Death Valley is an example of a rain shadow with mountain ranges on both sides.   &lt;a href=&quot;https://www.windows2universe.org/earth/atacama_desert.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Atacama desert&lt;/a&gt; is another.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rain shadows aren't part of your question, but the point is that Mountain ranges are especially good at pulling water vapor from the air and in cold enough climate, or if the mountains are tall enough, they're very good at creating localized glaciers that ebb and flow with the seasons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I disagree with the sentence in the other answer of glaciers have been receding for the last 15,000 years.   While somewhat true, given that you asked about mountain glaciers, that's a tricky assumption to make.   Sea-level studies suggest that glacial melt, significantly slowed down to a very gradual sea level rise by about 6,000-6,500 years ago.  If we assume (if I may speculate), a steady but gradual increase in East Antarctic ice, there has been some steady glacial melt globally over the last 6,000 years, but not a huge amount and whether mountain glaciers contributed to that is unknown.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/f8s8y.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/f8s8y.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Getting to your question, When the weather is warmer and there's more water vapor in the air, the amount of water that mountain ranges catch should increase on average.  That's 100% accurate, captured water only becomes glacier (or snow or frost), when the temperature is below freezing. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the other answer points out, it's a combination of a period of time below freezing and the amount of water vapor in the air that enables the mountain glaciers to grow.   But you also have to look at absolute humidity.  Air tends to be high relative humidity over oceans but over land there's much greater variation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wind generally &lt;a href=&quot;https://pmm.nasa.gov/education/content/why-do-storms-generally-move-west-east-usa&quot; rel=&quot;nofollow noreferrer&quot;&gt;blows in an easterly direction&lt;/a&gt; across the US, the US' western most mountain ranges are the Sierra Nevadas and the Cascades, and as noted above, mountains pull water-vapor from the air, so the western most mountain ranges capture a lot of the water-vapor who's source is the Pacific ocean.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cWDq8.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cWDq8.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Past those mountains, the air needs to fill up again with water vapor, sometimes called recycled water-vapor or secondary source water vapor.  This secondary source comes mostly from rivers and plant transpiration, but as CO2 levels rise, &lt;a href=&quot;https://phys.org/news/2011-03-co2-atmosphere.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;plant transpiration decreases&lt;/a&gt;, so you have a double whammy effect, air that can hold more water, and less water vapor returned to the air.   This means, by the time the air reaches the Rocky Mountains, there's often less, not more water vapor in the air, combined with a shorter winter season, and the glaciers can shrink significantly.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regions that rely on secondary sources of water vapor, such as rivers and transpiration, can be especially vulnerable to climate change.   Add to that, a decrease of snow melt from shrinking mountain glaciers upstream and you have a potentially serious water shortage issues . . . but I digress, as your question wasn't about water shortages.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No two mountain ranges are alike, so the details should be studied individually for each mountain range or region, but specifics such as where the wind that blows past that mountain gets it's water vapor from is very important, in addition to any variation in the time that mountain glacier spends above or below freezing.  That warmer air holds more water is true in general, but it's not globally true as a result of climate change.   Some parts of the Earth are becoming dryer as a result of climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's no shortage of articles that indicate that mountain glaciers are rapidly shrinking.    Mountain glaciers that rely on secondary sources of water vapor are the most vulnerable. &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2018-01-30T16:54:19.690" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13236" PostTypeId="5" CreationDate="2018-01-30T17:05:05.193" Score="0" Body="&lt;p&gt;The definition of &lt;a href=&quot;https://en.wikipedia.org/wiki/Glacier&quot; rel=&quot;nofollow noreferrer&quot;&gt;glacier&lt;/a&gt; is not written in stone. But basically any large mass of ice can be considered a glacier. But typically the term refers to ice masses that cover more than 10,000 m² and flow downhill in part due internal deformation driven by its own weight.&#xA;This tag should be associated to any question related to:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Particular glaciers&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Glacier physics and dynamics&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Properties of ice&lt;/strong&gt;, firn and snow&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;The effects of glaciers on their environment&lt;/strong&gt; (hydrological cycle, climate effects, etc.)&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Glaciar geomorphology&lt;/strong&gt; (moraines, cirque valleys, U-shaped, valleys, proglaciar lakes, etc.)&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;The evolution of glaciers through time&lt;/strong&gt; (glaciations, Milankovich cycles, snowball earth events, etc.)&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;The glaciers as a proxy of climate change&lt;/strong&gt; (ice cores, glacier recession and advance).&lt;/li&gt;&#xA;&lt;li&gt;Any other topic related to glaciers.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-03T19:27:01.640" LastActivityDate="2019-02-03T19:27:01.640" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="13237" PostTypeId="4" CreationDate="2018-01-30T17:05:05.193" Score="0" Body="Questions related to glaciers, glaciations and glaciology. Including the properties of ice, firn and snow, as well as topics related to glaciar geomorphology, such as moraines, U-shaped glacier valleys or proglacial lakes." OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-01-30T18:05:10.727" LastActivityDate="2018-01-30T18:05:10.727" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13240" PostTypeId="1" AcceptedAnswerId="13241" CreationDate="2018-01-30T22:58:29.477" Score="29" ViewCount="5163" Body="&lt;p&gt;The color of the ice observed in glaciers, icebergs and crevasses is often blue. However, ice cubes and industrial ice blocks are perfectly transparent or white if not.&lt;/p&gt;&#xA;&lt;p&gt;So. &lt;strong&gt;Why does glacier ice look blue?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Some examples of what I mean:&lt;/p&gt;&#xA;&lt;p&gt;Ice blocks&#xA;&lt;a href=&quot;https://i.stack.imgur.com/NinXd.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NinXd.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Glacier ice&#xA;&lt;a href=&quot;https://i.stack.imgur.com/GeJsr.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GeJsr.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;PS: As a glaciologist, this is a question I've received a lot, and after Googling for it, the answers I found are not fully satisfactory, so I decided to share mine here in a Q&amp;amp;A format.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-01-03T19:23:13.347" Title="Why does glacier ice look blue?" Tags="|glaciology|ice|glacier|light|cryosphere|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13241" PostTypeId="2" ParentId="13240" CreationDate="2018-01-30T22:58:29.477" Score="32" Body="&lt;p&gt;The short answer is: &lt;strong&gt;BECAUSE THE ICE IS BLUE&lt;/strong&gt;.&lt;br&gt;&#xA;Now we have to explain why it seems perfectly transparent on ice cubes and industrial ice blocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It has to do with the fact that most transparent materials are not perfectly transparent, and instead absorb (and/or scatter) part of the light that hits them. And when the transparency is better for one specific color (&lt;a href=&quot;https://en.wikipedia.org/wiki/Visible_spectrum&quot; rel=&quot;noreferrer&quot;&gt;wavelength&lt;/a&gt;), the material will look that color, much like how stained glass gives a tint to the white light going through it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now the important fact is that this &quot;tint&quot; effect is stronger the thicker the material is. Let's take a standard glass as a example: When looking through the glass it seems perfectly transparent, because the thickness is too small to make its color noticeable. However, if you look at the edge of the glass, it looks green, which shows that glass is indeed green, but that only became noticeable when looking through a section thick enough.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3vf75.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3vf75.png&quot; alt=&quot;glass&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Picture taken from &lt;a href=&quot;http://www.peakglass.ca&quot; rel=&quot;noreferrer&quot;&gt;peakglass.ca&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the same way, glacier ice is blue, but that can only be appreciated if the piece of ice you are looking at is thick enough. We can see this effect in the following picture of an iceberg, where sections of different thicknesses displays a color gradient ranging from transparent to blue.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/HdHIG.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HdHIG.jpg&quot; alt=&quot;ice colors&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The remaining questions is: Why are glaciers not always blue? As we know, many icebergs (and snow) are white.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The key here is &quot;bubbles&quot;. The reason is that for each ice/air interface, part of the light gets reflected and only a fraction goes through. Therefore the greater the number of bubbles a piece of ice has, the less light will be able to proceed deeper into the ice.  As such, when you view light from more bubbly ice, most of it will have traveled through less ice, and thus have had less distance to obtain the blue tint. I've made this figure to help understanding the idea:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/arZ5v.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/arZ5v.png&quot; alt=&quot;light in ice with bubbles diagram&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the left, a piece of ice with very few bubbles allows a longer travel path through the ice, inducing a marked blue tint in the outgoing light. On the right, in contrast, if there are many bubbles the light will go bounce back right away with only a very subtle tint, or no tint at all.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Snow is the extreme of this, because it is mostly air (bubbles), and only some small pieces of ice, that's why it looks so white.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An interesting ramification of this: those deep blue pieces of ice started as snow. But as the snow piles up, the weight of the snow on top compacts it, squeezing air out changing it from snow to &lt;a href=&quot;https://en.wikipedia.org/wiki/Firn&quot; rel=&quot;noreferrer&quot;&gt;firn&lt;/a&gt; until you finally reach the density of being a block of ice (with bubbles). In a big glacier, hundreds or thousands of meters of ice can exert such a pressure that the bubble spaces get compacted smaller and smaller until they disappear and the air is dissolved into the ice itself.&lt;br&gt;&#xA;Therefore this means that the more blue (and bubble-less) a piece of ice is, the more it has come from deeper within the glacier... meaning it also has traveled from further up in the glacier basin and it is, therefore, older. So, now you can identify deep, old ice just by its color.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To give a more familiar example of how adding bubbles can turn something transparent with a tint into something white, take the case of egg whites, which are transparent with a yellowish tint. But as you whip it, adding in bubbles, it begins to turn into meringue which is perfectly white.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/iPSe0.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iPSe0.jpg&quot; alt=&quot;making meringue&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, there is a trick that can even make the blue color of seemingly-white snow noticeable. If you let a ray of light bounce on it many times, each time it will travel through a little bit of ice, getting a bit of blue tint each time, and after enough bounces it will look unquestionably blue. That's what you see when looking at the entrance of a snow cave or a crevasse in a glacier. The light that comes from deeper in the cave has bounced many more times around the walls and becomes bluer:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/zmQrF.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zmQrF.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;(Picture taken from &lt;a href=&quot;https://outdoorlifenorway.com&quot; rel=&quot;noreferrer&quot;&gt;outdoorlifenorway.com&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-04T01:44:22.667" LastActivityDate="2019-02-04T01:44:22.667" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="13242" PostTypeId="2" ParentId="10511" CreationDate="2018-01-30T23:49:27.973" Score="9" Body="&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/10513/12095&quot;&gt;kingledion gave a great overview on the general scientific quality of the papers&lt;/a&gt;, but I don't think the title question has been really answered yet.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is the Unified Theory of Climate (Nikolov &amp;amp; Zeller) compatible with the AGW/GHG theory in any respect?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Yes.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;First, I too would comment on &lt;a href=&quot;https://doi.org/10.1186/2193-1801-3-723&quot; rel=&quot;noreferrer&quot;&gt;that preceding paper (&lt;em&gt;On the average temperature of airless spherical bodies...&lt;/em&gt;)&lt;/a&gt;. What it's concerned with is the equation&#xA;$$&#xA;  T_\mathrm{e} = \left(\frac{S_0\cdot(1-\alpha_\mathrm{p})}{4\cdot\epsilon\cdot\sigma}\right)^{1/4},&#xA;$$&#xA;which derives from the Stefan-Boltzmann law the &lt;em&gt;radiating equilibrium temperature&lt;/em&gt; $T_\mathrm{e}$. The main point of the paper is that this temperature is not in any way physically meaningful for airless bodies. Which is completely correct: airless bodies do indeed not have a &amp;ldquo;representative mean temperature&amp;rdquo;, because the integral over a function of some quantity (here, fourth power of temperature) isn't directly related to the function value of the &lt;em&gt;average&lt;/em&gt; of the quantity&lt;sup&gt;&amp;dagger;&lt;/sup&gt;. For a body without atmosphere like the moon, temperature varies extremely strongly over the surface, and thermal emission is completely dominated by the hot regions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This does not really give rise to any interesting conclusions though, because $T_\mathrm{e}$ isn't of much interest for climatology anyway. Any proper climate model is well aware of the importance of locally varying temperatures, as Volokin/ReLlez themselves admit:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It should be pointed out that global climate models intrinsically account for Hölder’s inequality by virtue of being three-dimensional and explicitly resolving the spatial heterogeneity of radiation absorption and emission (as well as other energy transport processes) within the context of a spherical geometry. However, 3-D models have not historically been applied to assess&#xA;  the strength of Earth’s ATE (GE). Hence, our critique is strictly directed towards the effective emission-temperature formula (3) and other similar 1-D radiative-transfer models (e.g. Manabe and Möller 1961; Manabe and&#xA;  Strickler 1964).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;One could also add here that $T_\mathrm{e}$ is not quite so meaningless for a planet &lt;em&gt;with substantial atmosphere but no greenhouse gases&lt;/em&gt;, because here the spatial temperature variations are less pronounced, yet the surface is in radiative equilibrium with the sun/space. I'll come back to that.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Now to &lt;a href=&quot;https://www.omicsonline.org/open-access/New-Insights-on-the-Physical-Nature-of-the-Atmospheric-Greenhouse-Effect-Deduced-from-an-Empirical-Planetary-Temperature-Model.pdf&quot; rel=&quot;noreferrer&quot;&gt;the paper you're asking about&lt;/a&gt;. It does two things:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Fit &lt;em&gt;generic models without a-priori physical motivation&lt;/em&gt; to observed values of pressure, density, greenhouse-gas content and observed and vacuum-predicted temperatures.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Try to take new physical conclusions from the fit result.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;kingledion discussed well how sensible this approach is in principle. Yes, it is sensible to &lt;em&gt;just fit the available data&lt;/em&gt;, if that's all you have available. It can even be valid to inter- or extrapolate from that data somewhat, using the fitted models as a guide. Nikolov/Zeller emphasize that they chose models which make such extrapolation particularly robust. Ok.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But there's one principle that anybody using statistical methods surely must always keep in mind: &lt;strong&gt;correlation does not imply causation&lt;/strong&gt;. What Nikolov/Zeller &amp;ldquo;find out&amp;rdquo; is that you get a marvellous fit when considering $\frac{T_s}{T_{\mathrm{na}}}$ as a function of $\frac{P}{P_r}$, namely&#xA;$$&#xA;\frac{T_s}{T_{\mathrm{na}}}&#xA;    = \exp\left(0.174205\cdot(\tfrac{P}{P_r})^{0.150263}&#xA;        + 1.83121\times10^{-5}\cdot(\tfrac{P}{P_r})^{1.04193}\right)&#xA;$$&#xA;gives a coefficient of determination $R^2 = 0.9999$. Wow!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this surprising?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Um, no. What they've discovered there is most of all the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ideal_gas_law&quot; rel=&quot;noreferrer&quot;&gt;ideal gas law&lt;/a&gt;. That connects pressure and temperature in a pretty rigid way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far, everything is... ok. Nothing actually &lt;em&gt;new&lt;/em&gt; (just long-known physics, re-discovered in an inefficient way). The trouble only really starts with the conclusions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nikolov/Zeller argue that this excellent fit, and the much worse fits of similar models relating other quantities &amp;ndash; in particular, greenhouse-gas concentrations &amp;ndash; mean that it's actually &lt;em&gt;only the pressure which influences the surface temperature&lt;/em&gt;, and that GHG are irrelevant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But that's completely and utterly fallacious!&#xA;&lt;br&gt;Again: it's not surprising that the ideal gas law holds &amp;ndash; rather, it would be extremely surprising if it didn't. So, the $T_s(P/P_r)$ fit tells up about as much as a fit of fall-times of weights from different heights in vacuum: &lt;em&gt;nothing&lt;/em&gt;, they just reaffirm the long-known Newton laws of motion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And it does &lt;em&gt;not&lt;/em&gt; mean that &amp;ldquo;temperature is only influenced by pressure&amp;rdquo;. On the contrary: just as much, &lt;em&gt;pressure is influenced by temperature&lt;/em&gt; &amp;ndash; if you somehow lowered the mean temperature of a given planet, surface pressure would drop as well&lt;sup&gt;&amp;ddagger;&lt;/sup&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Both&lt;/em&gt; pressure and temperature also depend on other quantities though. Notably, yes, on greenhouse-gas concentration. But unlike the gas law, the mechanism is a bit more complex and can't be captured properly&lt;sup&gt;&amp;para;&lt;/sup&gt; by fitting such a primitive model to a few measured points. Instead, it requires 3D climatology models, which incorporate &lt;em&gt;all of these quantities&lt;/em&gt;, and not just in a global-mean sense but in a detailed, latitude- and altitide-dependent way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I said I'd come back to the scenario of an atmosphere of significant density but without greenhouse gases. Such an atmosphere would keep spatial and temporal variations limited, but wouldn't influence the radiation processes, i.e. this is the case where the surface temperature would actually be similar to $T_\mathrm{e}$. How is this still compatible with the Nikolov/Zeller model 12? Well, again that model is mostly just the gas equation. Such an atmosphere would still obey it. The higher reaches would be colder than the surface due to adiabatic expansion. Really, this scenario isn't very exotic in terms of fundamental physics, but it illustrates that GHG are absolutely essential for a climate like Earths. The Volokin/ReLlez paper just proves that $T_\mathrm{e}$ isn't relevant for bodies without any atmosphere &lt;em&gt;at all&lt;/em&gt;, but that's hardly interesting for any discussions regarding Earth's climate.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&amp;dagger;&lt;/sup&gt;&lt;sub&gt;The paper specifically discusses the &lt;a href=&quot;https://en.wikipedia.org/wiki/H%C3%B6lder%27s_inequality&quot; rel=&quot;noreferrer&quot;&gt;H&amp;ouml;lder inequality&lt;/a&gt;, which is somewhat curious because that inequality actually states that there &lt;em&gt;is&lt;/em&gt;, for power functions, a relation between mean-of-the-function $\langle f(x)\rangle$ and function-of-the-mean $f(\langle x\rangle)$, namely, the latter gives an upper bound to the former. The H&amp;ouml;lder inequality does not actually imply that $\langle f(x)\rangle$ lies &lt;em&gt;beneath&lt;/em&gt; that upper bound &amp;ndash; it could just as well instead be &lt;em&gt;smack on the bound&lt;/em&gt;; but it's true that there are quantities for which it is substantially below.&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&amp;ddagger;&lt;/sup&gt;&lt;sub&gt;At that point, I am oversimplifying. There's a whole bunch of different scenarious what could happen when you alter a planet's surface temperature (even assuming you managed to do this in a way other than directly tweaking atmosphere properties). The pressure-drop case is what happens when it gets so cold that the formerly atmospheric gases condense onto the surface; this is relevant to e.g. Mars and Titan. In other planetary bodies, other mechanisms would step in; in either case however, you could be sure that the ideal gas law continues to hold.&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&amp;para;&lt;/sup&gt;&lt;sub&gt;Ironically enough, Nikolov/Zeller's Model 7 actually hints that greenhouse concentration does correlate to temperature, even though it lacks the quantities that would be needed to make the fit tight.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="12095" LastEditorUserId="12095" LastEditDate="2018-01-31T11:23:22.487" LastActivityDate="2018-01-31T11:23:22.487" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13243" PostTypeId="1" CreationDate="2018-01-31T02:35:20.143" Score="4" ViewCount="373" Body="&lt;p&gt;This isn't directly looking at a real life ecological example kind of thing, but it requires knowledge of relative dating, so I thought I would come here.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Uwifr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Uwifr.jpg&quot; alt=&quot;picture of the puzzle&quot;&gt;&lt;/a&gt;&#xA;Here is what was told:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-&quot;Worms&quot; (curved lines) tunnelled through a block of material that used to be rectangular. (C,D,F,J,H)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-faintly-circled letters represent &quot;cracks&quot; (discontinuities such as faults, I guess) (A,B,E,G,I)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-D is &quot;broken&quot; by B. (hard to tell in picture)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-Although there are ten letters, only 8 of them can be placed for certain. But we have to place the letters in order, say the two letters we cannot place for certain, and show all the possible locations where the other letters may be placed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is what I have so far:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I looked at the cracks first. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;E crack goes through A crack.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;B crack goes through A crack.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;B crack goes through I crack.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;B crack goes through G crack.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I crack goes through G crack.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;G crack goes through A crack.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using principle of cross-cutting relationships, order from oldest to newest here is A, G, I, ((E,B) or (B,E))&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then I looked at the worms to the earthquakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A --&gt; F goes through A, but J is broken by A.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;B --&gt; breaks C, H, F, J, and D&lt;/p&gt;&#xA;&#xA;&lt;p&gt;E --&gt; C goes through E, but J, D, F, and H are older.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;G --&gt; C goes through G, but D is broken by G&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I --&gt; F goes through I, but H is broken by I.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since B breaks all of the &quot;worms&quot; but E only breaks through four of the five &quot;worms,&quot; we can place the cracks as, from oldest to youngest&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A, G, I, E, B&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then I started to place the &quot;worms&quot; between the cracks using principle of cross-cutting relationships. I got in the end (oldest to youngest):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;J, A, G, I, F, E, C, B - D and H cannot be placed for certain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's all I have for now and it seems a bit off to me, but I can't place where? Am I doing this right?&lt;/p&gt;&#xA;" OwnerUserId="12114" LastEditorUserId="2470" LastEditDate="2018-01-31T07:30:00.190" LastActivityDate="2018-01-31T07:30:00.190" Title="Puzzle using relative dating principles" Tags="|rocks|earth-history|planetary-science|homework|dating|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13244" PostTypeId="2" ParentId="10837" CreationDate="2018-01-31T04:02:18.223" Score="6" Body="&lt;p&gt;Glaciers move by two processes:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Internal deformation&lt;/li&gt;&#xA;&lt;li&gt;Basal sliding&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;This figure (made for my candidacy exam), exemplify both processes as if we were following a single block of ice within a glacier:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Nwovq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Nwovq.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basal sliding is when the entire glacier slides together over the bedrock, aided by the lubrication of ice water between the glacier and ground.  Internal deformation is when the glacier moves by spreading out like honey on a table, but it can still be fix and frozen to the bed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But it is important to point out that the glaciers are still always moving in the same direction (downhill), caused by gravity. Therefore glaciers always advance and tend to remain together. (When we say that a glacier recedes, it means that the position of the front edge recedes, not the ice itself. And that happens when the ice at the front melts faster than it it replaced by the advancing movement.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Out of the two processes mentioned above, basal sliding is the main one in large glaciers and antarctic ice streams, but it is unable to work in cold-based glaciers (i.e. glaciers where the base is not above the melting point, and therefore glaciers frozen all the way to the bed and stuck to it) which are more common to Antarctica itself.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The picture you are proposing of a glacier splitting in two is a very rare occurrence. Because glaciers are very &lt;a href=&quot;https://en.wikipedia.org/wiki/Ductility_(Earth_science)&quot; rel=&quot;nofollow noreferrer&quot;&gt;ductile&lt;/a&gt; and have good cohesion, it can only happen in rare occasions on very steep mountain glaciers, where the driving stress and basal sliding can be strong enough to take a large fraction on the glacier and send it rushing downhill (&lt;a href=&quot;https://visibleearth.nasa.gov/view.php?id=88953&quot; rel=&quot;nofollow noreferrer&quot;&gt;like in this event&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Antarctica the glaciers are so big, and the terrain so flat that you can be sure that will never happen. Ice there will evolve more like a viscoelastic material - you can picture that by imagining how honey will move if you pour a jar of it over a table.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When people talk about Antarctica splitting in two they don't mean that the land will move apart, nor that the glaciers themselves will move in different directions and fracture.  Instead it is about the loss of the ice; as ice creeps to the edges of the continent and is lost as icebergs, the snowfall inside the continent is not enough to replenish the ice lost. Therefore, the ice sheet over the continent is thinning. The land of Antarctica (without any ice) is made up of two separate big landmasses (East and West Antarctica) and a multitude of islands.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qQqsF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qQqsF.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the ice sheet thins, at some point sea water will progress towards the large areas with bases currently below sea level, the ice start to float, and will eventually completely break up. If that were to happen, Antarctica would become split into two sub-continents, and the ice loss would generate a catastrophic sea level rise.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-01-31T17:31:46.647" LastActivityDate="2018-01-31T17:31:46.647" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13245" PostTypeId="1" CreationDate="2018-01-31T05:46:58.963" Score="4" ViewCount="143" Body="&lt;p&gt;What is the status of the Early Anthropocene hypothesis, in the specific meaning that the climate would be projected to be significantly cooler (such as, on the order of by 0.8 degrees in the planet average) in a year corresponding to, say, 1800, if there was no agricultural revolution and no significant impact of our species on the climate starting several thousand years before that?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a layman's question.  I'm familiar with Ruddiman's work and some of its early criticisms, but I'm unsure what the current generation of scientists thinks about the issue and if there's any strong recent evidence either way which I should read about.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please don't focus too much on my use of the terms &quot;anthropocene&quot; or &quot;glaciation&quot; themselves in this question, but feel free to suggest better ways to refer to the above hypothesis or its current successors.&lt;/p&gt;&#xA;" OwnerUserId="12117" LastEditorUserId="11908" LastEditDate="2018-01-31T20:27:25.470" LastActivityDate="2018-02-01T02:37:29.427" Title="Status of overdue glaciation hypothesis" Tags="|climate-change|glaciology|glaciation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13247" PostTypeId="1" CreationDate="2018-01-31T15:29:21.800" Score="4" ViewCount="419" Body="&lt;p&gt;I am in a Marine Environmental Science II class, and we are discussing the Ekman Spiral. As I understand, the Coriolis Effect does not occur when whatever is observed does not change latitude. So, if a wind above the ocean in the Northern Hemisphere were to hypothetically blow due East, with no change in latitude, would the water under the wind still be deflected to the right in the form of the Ekman Spiral?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks in advance!&lt;/p&gt;&#xA;" OwnerUserId="12123" LastActivityDate="2018-01-31T17:39:15.873" Title="If a prevailing wind traveled due east in the Northern Hemisphere, would the Coriolis Effect act on the water?" Tags="|wind|ocean-currents|coriolis|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13248" PostTypeId="2" ParentId="13247" CreationDate="2018-01-31T16:14:12.587" Score="5" Body="&lt;p&gt;The Coriolis Effect occurs in all directions equally, even straight zonal (east-west) winds.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many indeed struggle with this idea - &lt;a href=&quot;https://physics.stackexchange.com/questions/43124/is-there-an-intuitive-explanation-for-the-southward-force-caused-by-the-coriolis&quot;&gt;this Physics SE question&lt;/a&gt; has a fair explanation as to why.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As arkaia commented, the total deflection magnitude is $f=2{\omega}\cdot{\sin(latitude)}$, which is an orthogonal vector change (and as such shows up as terms in both the &lt;a href=&quot;https://en.wikipedia.org/wiki/Primitive_equations#Forms_of_the_primitive_equations&quot; rel=&quot;nofollow noreferrer&quot;&gt;zonal and meridional velocity equations&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So there's still deflection to the right (in the NH) equally regardless of which direction the air/water is flowing (except that in such a feature, deeper water is moving slower, so deflects by less magnitude... but still matching in regards to the proportion in comparison to the velocity).  Otherwise the result would not be &lt;a href=&quot;https://en.wikipedia.org/wiki/Ekman_spiral&quot; rel=&quot;nofollow noreferrer&quot;&gt;a spiral&lt;/a&gt;... but only at most a 90° decaying curve, since as the water begins to turn towards a more zonal direction, the angle of deflection would start to decrease, until at some height the water is moving easterly (or westerly) (such as at height labeled 3 in &lt;a href=&quot;https://en.wikipedia.org/wiki/Ekman_spiral#/media/File:Ekman_spirale.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;this diagram&lt;/a&gt;), and the water below it wouldn't turn further.  So the direction independence of Coriolis is vital to there being Ekman spirals at all.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-01-31T17:39:15.873" LastActivityDate="2018-01-31T17:39:15.873" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13250" PostTypeId="2" ParentId="12459" CreationDate="2018-01-31T19:17:54.747" Score="2" Body="&lt;p&gt;&lt;a href=&quot;http://www.nytimes.com/1987/10/29/us/air-from-dinosaurs-age-suggests-dramatic-change.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Recent analysis&lt;/a&gt; of the contents of air bubbles preserved in prehistoric amber reveal the oxygen composition to be 32% back then compared to just under &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_chemistry#Atmospheric_composition&quot; rel=&quot;nofollow noreferrer&quot;&gt;21% today&lt;/a&gt;.  These tiny bubbles have remained trapped in these amber samples for about 80 million years, which dates them well into the Cretaceous era when dinosaurs and other huge creatures roamed the earth.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Said analysis also revealed that nitrogen made up the rest save 1% for Argon, CO2, and other trace gases. The percentage of CO2 was not specifically stated but mentioned as similar oxygen to CO2 ratio as today's atmosphere.  Whether the total air pressure air density of the atmosphere was greater back then is not mentioned, most likely because this would be difficult to ascertain from the samples.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An atmosphere 50% richer in oxygen but at the same atmospheric pressure and density at sea level as today would have allowed land animals to get by with a lower lungs to total body mass ratio and thus allowed the existence of extra massive creatures such as dinosaurs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I assert that the asteroid that struck the Yucatan area 65 million years ago caused most of the forests and other terrestrial vegetation to ignite into flames.  The whole earth would have been on fire, at the end of which the &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Sauerstoffgehalt-1000mj.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;oxygen levels were depleted&lt;/a&gt; to &lt;a href=&quot;https://en.wikipedia.org/wiki/File:OxygenLevel-1000ma.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;what they are today&lt;/a&gt;.  This is confirmed by analysis amber air bubbles from 40 million years ago, post asteroid impact, revealing an &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Phanerozoic_Carbon_Dioxide.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;atmospheric composition&lt;/a&gt; and oxygen levels closer to today's.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Dinosaurs and other massive terrestrial animals could not then make a comeback since the lower oxygen content of the atmosphere would have restricted metabolism to maintain massive body sizes.&lt;/p&gt;&#xA;" OwnerUserId="8212" LastEditorUserId="8212" LastEditDate="2018-02-02T13:43:57.097" LastActivityDate="2018-02-02T13:43:57.097" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13251" PostTypeId="2" ParentId="10810" CreationDate="2018-01-31T20:25:17.373" Score="6" Body="&lt;p&gt;I can't imagine a moving object  more suitable for remote sensing tracking than Iceberg A-68, with such slow displacement and huge size. So I don't think it will be particularly useful to install any instrumentation to track its position on site.&#xA;However, there would be plenty of other measurements that can be done, about mass balance, stress fields, etc.&#xA;I'm not aware of any plans to install such instrumentation. I've emailed Thomas Rackow (the author of the paper cited above), and he is not aware of any plans either, and confirmed that no instrumentation have been installed so far. But, that can easily change in the future.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;He pointed me to an expedition happening next month to study the marine ecosystem that have been exposed by the departure of A-68, you can find out more in &lt;a href=&quot;https://phys.org/news/2017-10-scientists-hidden-antarctic-ecosystem-giant.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this link&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By the way, a cool tool to track A-68 position is &lt;a href=&quot;https://worldview.earthdata.nasa.gov/?p=geographic&amp;amp;l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor,MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels(hidden),Reference_Features(hidden),Coastlines&amp;amp;t=2018-01-16&amp;amp;z=3&amp;amp;v=-64.8367463639102,-70.07509944085103,-56.399246363910194,-65.97500178460103&quot; rel=&quot;nofollow noreferrer&quot;&gt;Worldview&lt;/a&gt;, this is an image taken on January 16th (there are images as fresh as today, but it have been cloudy sice then):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/uqtxp.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uqtxp.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But due to the frequent cloud  coverage your best bet are radar images. A great search portal is &lt;a href=&quot;https://vertex.daac.asf.alaska.edu/#&quot; rel=&quot;nofollow noreferrer&quot;&gt;VERTEX&lt;/a&gt; from the Alaska Satellite Facility. I just made a search, and there is an image of today, but I liked more this one taken yesterday (January 31st 2018) by the satellite Sentinel-1A&#xA;&lt;a href=&quot;https://i.stack.imgur.com/MlwT3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MlwT3.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-04-13T21:00:46.437" LastActivityDate="2018-04-13T21:00:46.437" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="13253" PostTypeId="2" ParentId="12075" CreationDate="2018-02-01T00:12:44.237" Score="8" Body="&lt;p&gt;That's a very interesting study, but only provide very rough information on the posible volcanoes that might exist under the ice.&#xA;In the case of the volcanoes shown in the radargram I'll highlight some points that might be the source of your confusion:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The tephra layer that overlay the volcanoes in the radargram was not erupted  by those volcanoes. It was most likely erupted by a volcano from above the ice (subaerial), or a subglacial one far away. It was later buried deep in the ice by the snow falling on top. Otherwise the layers would be much messier in the area and of varying thickness.&lt;/li&gt;&#xA;&lt;li&gt;If those cone are volcanoes, its shape suggest that they were formed before they became covered in ice. Subglacial eruptions form flat-topped volcanoes with steep sides calles &lt;a href=&quot;https://en.wikipedia.org/wiki/Tuya&quot; rel=&quot;noreferrer&quot;&gt;Tuyas&lt;/a&gt;, and what is observed are broad shield-type cones, that suggest submarine or subaerial formation.&lt;/li&gt;&#xA;&lt;li&gt;They don't know if those volcanoes are active, but if one were to start an eruption, wouldn't be of the explosive type, because are likely to have fluid basaltic lavas, like the ones observed in Hawai'i. The explosiveness will come from the steam produced. It is hard to tell if it will blow the ice on top or not. It depends on ice thickness, eruption power, etc. But it is definitely a possibility for a strong enough eruption.  &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-02-01T00:20:02.357" LastActivityDate="2018-02-01T00:20:02.357" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13254" PostTypeId="1" CreationDate="2018-02-01T00:48:07.880" Score="1" ViewCount="1124" Body="&lt;p&gt;Im trying to do an assessment but I just can answer this question!&lt;/p&gt;&#xA;" OwnerUserId="12129" LastActivityDate="2018-02-01T02:06:31.980" Title="What disciplines of science are used in the locating and extraction of mineral resources?" Tags="|mineralogy|" AnswerCount="1" CommentCount="1" ClosedDate="2018-02-03T08:25:37.387" ContentLicense="CC BY-SA 3.0" />
  <row Id="13256" PostTypeId="1" AcceptedAnswerId="13333" CreationDate="2018-02-01T01:23:01.547" Score="10" ViewCount="627" Body="&lt;p&gt;The geological record at the end of the Anthropocene will undoubtedly contain large volumes of plastic.  However, some geological processes will completely destroy plastic (e.g. magmatic or chemical processes).  I assume that sedimentary rocks will contain plastic pellets at the least and that igneous rocks will not.  Which geological processes that create metamorphic rock will be able to completely destroy plastic molecules?&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="94" LastEditDate="2018-02-08T16:46:44.897" LastActivityDate="2018-02-11T13:38:48.673" Title="Which geological processes will destroy plastic?" Tags="|geology|metamorphism|anthropocene|plastic|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="13257" PostTypeId="2" ParentId="13254" CreationDate="2018-02-01T02:06:31.980" Score="5" Body="&lt;p&gt;The locating and extraction of mineral resources is essentially a three step process - find, extract and process.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first step of finding the mineral resources requires the use of &lt;strong&gt;geophysics&lt;/strong&gt;, &lt;strong&gt;geochemistry&lt;/strong&gt;, sometimes &lt;strong&gt;geobiology&lt;/strong&gt; and &lt;strong&gt;geology&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Geophysics&lt;/strong&gt; uses techniques such as magnetic studies, geological resistivity and seismic analysis to find geological anomalies. Which techniques are used depends on the minerals sought (metal sulphides or oxides), the overall host geology of the region, the remoteness of a region and proximity to infrastructure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Geochemistry&lt;/strong&gt; generally involves taking multiple surface samples for chemical analysis over an area of interest to ascertain if there are any geochemical anomalies. One that comes to mind is following gold samples up a river to locate the hard rock source of the gold.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Geobiology&lt;/strong&gt; is the use of plants to locate, or discover, a mineral deposit. One example that comes to mind was the discovery of the &lt;a href=&quot;https://www.mindat.org/loc-10618.html&quot; rel=&quot;noreferrer&quot;&gt;Viscaria copper deposit&lt;/a&gt; in Sweden due to a particular flower that grew over the deposit and not anywhere else in the region. The deposit was named after the flower that lead to its discover - Viscaria alpina (Lychnis alpina, &quot;copper flower&quot;). Geobiology is not widely used.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Geologists&lt;/strong&gt; follow up any interesting anomalies discovered by these techniques with field mapping and drilling and the analysis of drill hole sampling.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The extraction of minerals from the ground is the domain of &lt;strong&gt;mining engineers&lt;/strong&gt;. They take the models produced by geologists and determine where the mine should be located - because mineral deposits are not uniform and vary widely. They also determine which parts of the mineral deposit should be mined and how it is to be mined - open pit, underground, small or large scale stoping. They also determine the equipment to be used and with help from &lt;strong&gt;geotechnical/geomechanical engineers&lt;/strong&gt; they determine the maximum size of openings that the ground can support during mining operations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once mineral bearing rocks (ore) have been mined, the minerals must be removed and concentrated. This is done by &lt;strong&gt;metallurgists&lt;/strong&gt; in a processing plant. Depending on the minerals being processed, this can involved froth flotation (copper, zinc, lead, nickel), gravity techniques such as shaking tables (tin) or spirals, carbon in pulp processing (gold), magnetic separation (mineral sands), heavy media separation (iron ore). Most mineral processing methods require the use of water. Further refining is done by another group of metallurgists during smelting, if smelting is required.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-02-01T02:06:31.980" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13258" PostTypeId="2" ParentId="13245" CreationDate="2018-02-01T02:37:29.427" Score="1" Body="&lt;p&gt;Our interglacial ends some 1500-years from now, the AGU recently recognized the Holocene as geo-engineered by people converting forest to agriculture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We passed a warm-ocean tipping point for northern hemispheric winters, frozen oranges in Florida and rain in Alaska now will be common.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Our emissions rate is far beyond natural systems, the rate of change coming out of the last ice-age was 1-ppm/180-years, we hit 3ppm/year in 2016, 540-times faster.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And, the max CO2 during the late Pleistocene was 305-ppm, we hit that in 1916 and added 100-ppm in 100-years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This carbon bomb is acidifying the oceans 10-times faster than the worst land extinction in geologic history.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's very unwise what we're doing.&lt;/p&gt;&#xA;" OwnerUserId="12130" LastActivityDate="2018-02-01T02:37:29.427" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13259" PostTypeId="2" ParentId="13221" CreationDate="2018-02-01T03:43:45.007" Score="1" Body="&lt;p&gt;Venice has plans for a new hydraulic flow controlled by levees and a dam during runoff &amp;amp; tidal events as sealevel continues to rise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This has a brief summary of progress: &lt;a href=&quot;https://www.citylab.com/life/2016/09/venices-vast-new-flood-barrier-is-almost-here/498935/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.citylab.com/life/2016/09/venices-vast-new-flood-barrier-is-almost-here/498935/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[edit]&#xA;The context of Venice has 3 parts, the freshwater seasonal and episodic flow including groundwater in a relic delta, this with enough fetch to sea  allowing winds to pile water for days, and, there are seasonal tides with that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The almost complete solution deals with sediment compaction separately from defense against high water, those solutions have injection strategies, they're dealing with pore-pressure, flow and having clean water in the canals or they stink.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My view, it's analogous to the high water dam against the North Sea that's closed for storms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Long-term a dam at Gibraltar Strait, 1200-ft deep has been proposed to save history, otherwise we hit 3mm in a year in 2016 of rise, at 600-ppm Antarctica's land ice begins an unstoppable melt as is going on with submerged valley glaciers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To the question of littoral habitat that's ok unless there's an oil spill, pollutants in runoff are poisoning it pretty fast being an enclosed sea vs oceanic facing littorals from my reading.&lt;/p&gt;&#xA;" OwnerUserId="12130" LastEditorUserId="12130" LastEditDate="2018-02-01T18:04:55.797" LastActivityDate="2018-02-01T18:04:55.797" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13262" PostTypeId="1" AcceptedAnswerId="17517" CreationDate="2018-02-01T15:05:50.260" Score="6" ViewCount="1911" Body="&lt;p&gt;As I understand it, the metamorphic field gradient is the PT line traced out by the maximum temperature points of a series of PTt paths of rocks from the same metamorphic event.&lt;a href=&quot;https://i.stack.imgur.com/LyfSj.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LyfSj.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What exactly is this useful for? It seems that it doesn't really describe anything of physical significance since the $\mathrm{T_{max}}$ points can occur at different times so it doesn't represent a snapshot of the geothermal gradient at any fixed time.&lt;/p&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2019-07-20T00:39:42.137" Title="What is the metamorphic field gradient useful for?" Tags="|geology|tectonics|metamorphism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13264" PostTypeId="2" ParentId="13206" CreationDate="2018-02-01T19:34:21.047" Score="4" Body="&lt;p&gt;More moisture in the atmosphere also means less orographic lifting is required to reach saturation. This should lead to rain or snowfall at lower elevations, where it would melt more rapidly and not contribute to snowpack.&lt;/p&gt;&#xA;" OwnerUserId="6313" LastActivityDate="2018-02-01T19:34:21.047" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13265" PostTypeId="1" AcceptedAnswerId="20734" CreationDate="2018-02-01T21:20:49.843" Score="10" ViewCount="771" Body="&lt;p&gt;After every sunset, once the sun is gone, I always enjoy seen the &lt;a href=&quot;https://en.wikipedia.org/wiki/Belt_of_Venus&quot; rel=&quot;noreferrer&quot;&gt;belt of venus&lt;/a&gt; rising in the other side, followed by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_shadow&quot; rel=&quot;noreferrer&quot;&gt;Earth's shadow&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a picture I took (you will find better ones online). The Pinkish-purple band on top is the Belt of Venus, and the blue band on the bottom is the Earth's shadow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ul674.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ul674.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This figure from &lt;a href=&quot;http://www.skyandtelescope.com/astronomy-news/observing-news/earths-shadow-07292014/&quot; rel=&quot;noreferrer&quot;&gt;Sky &amp;amp; Telescope&lt;/a&gt; explains it well:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Rn1F5.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Rn1F5.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While contemplating these beauties, I've had hard time understanding why we see the colors we do. To my eyes, the belt of Venus looks purple, which didn't makes sense to me, as the very short wavelength of purple light should have been scattered long before arriving back there. Then all made sense when I realized that if you mix blue and red light you get purple. So the color comes from the blue mixed with the red light backscattered by the high atmosphere that is still illuminated by the Sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I can't still figure out &lt;strong&gt;why the Earth's shadow looks blue&lt;/strong&gt;, and I haven't been able to find an answer (here some links about the Earth's shadow but without an explanation of the color: &lt;a href=&quot;http://www.meniero.it/articoli/meteo/en/Earth%20Shadow.php&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;http://www.skyandtelescope.com/astronomy-news/observing-news/earths-shadow-07292014/&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_shadow&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We know the sky is blue and the sunset red to due the &lt;a href=&quot;http://math.ucr.edu/home/baez/physics/General/BlueSky/blue_sky.html&quot; rel=&quot;noreferrer&quot;&gt;preferential scattering of blue light&lt;/a&gt; by the air. But: &lt;strong&gt;How can the air in the Earth's shadow scatter blue light if it doesn't get any direct illumination, and any indirect illumination getting back there should be VERY depleted in blue (i.e. mostly red light)?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I thought the fact that the belt of Venus scatters red instead of blue as the rest of the atmosphere, is precisely because back there there is no more blue light left, so the weaker scattering of red light becomes noticeable (please let me know if I'm wrong there).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Or is the air actually emitting blue light in some sort of &lt;a href=&quot;https://en.wikipedia.org/wiki/Fluorescence&quot; rel=&quot;noreferrer&quot;&gt;fluorescence&lt;/a&gt;/glowing?&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS: As this is a purely atmospheric phenomena I though it would be better suited here than in the Astronomy SE.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-02-01T21:57:38.433" LastActivityDate="2021-01-28T09:40:40.587" Title="Why is the Earth's shadow blue?" Tags="|atmosphere|atmospheric-chemistry|atmospheric-radiation|upper-atmosphere|air|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13266" PostTypeId="2" ParentId="13265" CreationDate="2018-02-02T01:43:49.097" Score="8" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;To my eyes, the belt of Venus looks purple, which didn't makes sense to me, as the very short wavelength of purple light should have been scattered long before arriving back there. Then all made sense when I realized that if you mix blue and red light you get purple.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You got that part right. Purple is not violet. Violet is a spectral color at the high frequency end of the visible portion of the spectrum, while purple is a non-spectral color on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Line_of_purples&quot; rel=&quot;noreferrer&quot;&gt;line of purples&lt;/a&gt; that spans from nearly ultraviolet to nearly infrared. We see color as a wheel rather than as a line. One possible explanation is that the long wavelength (&quot;red&quot;) cones have a secondary response in the violet end of the spectrum. Spectral violet light excites both the short wavelength and long wavelength cones, but so does a non-spectral mix of red and blue light.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And that's what you're seeing in the Belt of Venus -- a muted mix of red and blue, or a purple (or perhaps magenta, or a rosy pink).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;So the color comes from the blue mixed with the red light backscattered by the high atmosphere that is still illuminated by the Sun. However, I can't still figure out why the Earth's shadow looks blue.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The backscattered red light doesn't come from the high atmosphere. It comes from the troposphere. The high atmosphere (the stratosphere and above) contains very few particulates. The upper atmosphere is the only part of the atmosphere that remains sunlit above the eastern horizon after sunset. The sunlight hitting the upper atmosphere is Rayleigh scattered, so you see that very faint blue scattered light. You don't see the backscattered reddish light from the particulate-containing lower atmosphere at the eastern horizon because that part of the atmosphere is fully in the Earth's shadow above the eastern horizon.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-02-02T01:43:49.097" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13267" PostTypeId="2" ParentId="12586" CreationDate="2018-02-02T16:29:32.457" Score="2" Body="&lt;p&gt;It really depends on whether you're model is hydrostatic or not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If your model is hydrostatic, then the vertical velocity is found diagnostically. The diagnostic algorithm is called the &lt;a href=&quot;https://www.ecmwf.int/sites/default/files/elibrary/2003/8503-calculating-vertical-motion-using-richardsons-equation.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Richardson Equation&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If your model is nonhydrostatic, often it is presumed that the vertical velocity is 0. The vertical velocity is presumed to be 0 (unless you do some spin-up or model restart, or some other special initialization), and the prognostic equation for vertical velocity is found.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2018-02-02T16:29:32.457" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13268" PostTypeId="2" ParentId="8515" CreationDate="2018-02-02T16:59:45.067" Score="0" Body="&lt;p&gt;Put simply, the coriolis 'force' doesn't change wind speed, but the direction the wind blows. I would say that the winds would become much faster. Consider these facts:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The speed of the wind is modulated mostly by winds moving winds, friction, and how pressure changes over space.&lt;/li&gt;&#xA;&lt;li&gt;Pressure is proportional to temperature and density.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So if the world stopped rotating,&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;One side of the world would become warmer and warmer, as the other side cools. Therefore, the pressure on the side of earth with the sun would rise and the pressure of the dark side would decrease.&lt;/li&gt;&#xA;&lt;li&gt;With the ever growing change in pressure, the winds will increase to try to move the high pressure (warm) air toward the lower pressure (cool) air.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="704" LastActivityDate="2018-02-02T16:59:45.067" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13270" PostTypeId="1" AcceptedAnswerId="13296" CreationDate="2018-02-02T20:55:54.577" Score="1" ViewCount="169" Body="&lt;p&gt;If I dig up a given rock, make a 3d model of it, and compare that model with those of a large number of other rocks from the same area, what fraction of other rocks would have the same 3d model?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's say that the measurement is performed with an accuracy relative to the size of the rock, so a rock that fits within a 100cm sphere might be measured to within the nearest centimeter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It would be fine to only look at rocks that have been through similar geological processes, rather than all rocks in an area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm broadly interested in an answer for all land areas on Earth, but if there's data for some small region, or theories about rock shape that allow estimating the average entropy, that would be a useful answer.&lt;/p&gt;&#xA;" OwnerUserId="12142" LastActivityDate="2018-02-05T16:50:36.710" Title="how much entropy is there in the shape of a rock?" Tags="|geology|mathematics|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13272" PostTypeId="1" AcceptedAnswerId="13275" CreationDate="2018-02-03T06:59:49.807" Score="3" ViewCount="103" Body="&lt;p&gt;What are the main characteristics of CMIP5 Historical experiments?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;e.g. &#xA;Initial conditions? Greenhouse gases forcing?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How they differ from RCPs? And how they are similar to Observed reanalysis data?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks &lt;/p&gt;&#xA;" OwnerUserId="11493" LastActivityDate="2018-02-03T07:38:27.770" Title="CMIP5 Historical experiments, what do they mean?" Tags="|meteorology|climate|climate-models|climatology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13273" PostTypeId="1" CreationDate="2018-02-03T07:10:11.317" Score="1" ViewCount="224" Body="&lt;p&gt;I understand that cumulonimbus clouds can create lightning, but do not understand how many of them create lightning.  I would assume that most multi-cell systems would have lightning, while single cell systems would have less of a chance at creating lightning. &#xA; Is that right?  What percentage of cumulonimbus clouds create lightning? &lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2018-02-06T03:24:19.577" LastActivityDate="2018-02-06T21:43:12.383" Title="What percentage of cumulonimbus clouds create lightning?" Tags="|meteorology|lightning|thunderstorm|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13274" PostTypeId="2" ParentId="10066" CreationDate="2018-02-03T07:28:29.290" Score="2" Body="&lt;p&gt;Yes, the equation can be generalized as you mentioned. The method used to drive it is pretty close to humidity and temperature formulas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will start with neutral case and apply law of the wall, it is pretty simple to drive the following equation with Fc as diffusive flux and K as an empirical constant (NOT von-Karman) and also you can get C* from here by setting z = z0:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Gw6Ka.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Gw6Ka.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Remind yourself that Monin-Obukhov length scale (L) is simply the ratio of shear production to buoyancy in TKE budget and is NOT tracer dependent. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now back to dimensional analysis. The group of variables are unique to our problem are : &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;1) z/z0&lt;/strong&gt; , &lt;strong&gt;2) C/C*&lt;/strong&gt; and&#xA;&lt;strong&gt;3) **z/L&lt;/strong&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;where C is mean concentration (C bar in previous equation). Similar to what we do for temperature and humidity. A ψc can be calculated by choosing the second and the third group as independent variables and we would arrive at your equation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding the Gaussian plume, Remember that the equations you posted are only applicable near a boundary and only used to drive eddy diffusivity close to the wall layer e.g. wind tunnel, ocean, and earth. If I recall correctly Gausian plume model use different diffusivities compared to these and are more appropriate to interior of the flow.&lt;/p&gt;&#xA;" OwnerUserId="12143" LastActivityDate="2018-02-03T07:28:29.290" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13275" PostTypeId="2" ParentId="13272" CreationDate="2018-02-03T07:38:27.770" Score="4" Body="&lt;p&gt;The CMIP5 experimental protocol is documented at &lt;a href=&quot;https://cmip.llnl.gov/cmip5/docs/Taylor_CMIP5_design.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://cmip.llnl.gov/cmip5/docs/Taylor_CMIP5_design.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The historical experiment for a model spans model years 1850-2005 and is initialized from a control experiment for that model (forcings from 1850 are used repeatedly).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For models that are not coupled to a modeled carbon cycle, greenhouse gas forcing are based on the observed record (including ice cores) of atmospheric concentrations. For models that are coupled to a modeled carbon cycle, atmospheric CO2 concentration is predicted, and the model is forced with anthropogenic CO2 emissions (and land use change).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;RCPs are extensions into the 21st Century. There are different RCPs, based on different assumptions about future greenhouse gas concentrations and/or emissions, land use, population, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reanalysis data is from a model this is constrained to be close to observations of the atmospheric state (e.g., air temp, winds, pressure, etc.) This differs from CMIP models that run unconstrained.&lt;/p&gt;&#xA;" OwnerUserId="6024" LastActivityDate="2018-02-03T07:38:27.770" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13276" PostTypeId="2" ParentId="9974" CreationDate="2018-02-03T07:47:58.760" Score="1" Body="&lt;p&gt;&lt;em&gt;K&lt;/em&gt; is in fact just an empirical proportionality value without any significant meaning. In fact each of the tracers (such as temperature, humidity and ...) should have had their own &lt;em&gt;K&lt;/em&gt; &lt;strong&gt;BUT&lt;/strong&gt; we dump that coefficient into the (star)* version of that tracer, for example T* (near surface temperature) or Hum* (near surface humidity), so we can still use &lt;em&gt;K&lt;/em&gt; in their respective formulation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Monin-Obukhov length has &lt;em&gt;K&lt;/em&gt; in it because that length is related to u*. That length comes from dividing the Shear production and buoyancy procution/dissipation term in turbulence kinetic energy (TKE) equation. As you know Shear production is a function of momentum transfer and u*. Since there is a u* there is a &lt;em&gt;k&lt;/em&gt; in there too. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unlike other stuff in turbulence, the story of &lt;em&gt;K&lt;/em&gt; is unfortunately boring.&lt;/p&gt;&#xA;" OwnerUserId="12143" LastActivityDate="2018-02-03T07:47:58.760" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13277" PostTypeId="2" ParentId="9786" CreationDate="2018-02-03T07:55:01.163" Score="1" Body="&lt;p&gt;I am assuming you know how to get to mixing from velocity field since you are talking about the noise in the ADCP data. The way people get the small fluctuation and vertical mixing profiles that are highly trusted are with &quot;micro-structure&quot; sampling technique. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please follow this link for more detail on that technique. &#xA;&lt;a href=&quot;https://earthobservatory.nasa.gov/blogs/fromthefield/2012/10/04/what-is-ocean-microstructure-and-why-study-it/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earthobservatory.nasa.gov/blogs/fromthefield/2012/10/04/what-is-ocean-microstructure-and-why-study-it/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12143" LastActivityDate="2018-02-03T07:55:01.163" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13279" PostTypeId="2" ParentId="13273" CreationDate="2018-02-03T09:39:05.643" Score="1" Body="&lt;p&gt;I've done some research studies about the flash rate in various storms. My paper is now in review, but here is some info from this paper:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We have computed measurements for supercell and moderate thunderstorms, counting CG+ discharges. There are 24 times more discharges in supercells than in moderate thunderstorms. Supercells on average had better thermodynamic conditions to develop into a huge storm cluster.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only help to answering your question is that Cb clouds are not similar to each other. But what I can tell you is that Cb lightning in my studies for CG+ discharges occurred once a minute, whereas for a supercell this number is equal to 24 per minute.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I studied thunderstorms from 19th of July 2015 and 17th of April 2016 over Poland.&lt;/p&gt;&#xA;" OwnerUserId="11875" LastEditorUserId="6298" LastEditDate="2018-02-06T21:43:12.383" LastActivityDate="2018-02-06T21:43:12.383" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13280" PostTypeId="1" CreationDate="2018-02-03T18:31:15.890" Score="10" ViewCount="11229" Body="&lt;p&gt;It is long time that I am looking for what physical reason(s) explains this observation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;the sun ambient light between sunrise and midday is crispy, somehow whiter than that of the afternoon hours. In other words it is like that morning outdoor light is more similar to that of a white lamp, and that of afternoon more yellow and incandescent bulb -'like.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even in more physics term, it seems that the morning light has a higher Temperature than that of afternoon. Note that I refer to the T of an emitting black body, not the temperature as colloquially used in fashion, art, etc that goes right the other way around.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For those just a bit familiar with photography, is as the golden hours of morning and afternoon are not identical (the obvious opposite casting of shadow is obviously not part of the matter), like if the source of lighting changes (obviously the sun doesn't, so it is an atmospheric phenomenon or so).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Everything I came up would have a basically symmetric behaviour around midday so can't explain this. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only asymmetry I can see is that &quot; morning is light through a night chilled atmosphere&quot;, while &quot;afternoon is light going around in an already warmed up atmosphere&quot;. However &quot;this explanation&quot; - as a ground where to plug optical phenomena of refraction or Mie scattering - would require about the same temperatures of the air, in summer as in winter,  or day after day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another possible asymmetry is due to our long scale adaptation to luminosity or brightness, but the change I refer to is relatively abrupt around noon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A possibility might be related to temperature of the atmosphere perhaps via refraction between layers of it..... it is the last idea that came to my mind. In this case same layering might occur independent of seasons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please note that I am not asking for Rayleigh scattering alone and why yellow and red are dominant near horizon at sunrise or sunset.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;I am asking why the light of a clear day is not symmetrically changing centered at noon&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please also note that before telling me that the difference I am asking about does not exist, ask yourself if you feel able to tell if it is morning or afternoon without knowing anything else but looking at the environmental light in a clear day. Most persons I've talked to about this, didn't realise it before (again a big surprise).&lt;/p&gt;&#xA;" OwnerUserId="12148" LastEditorUserId="12148" LastEditDate="2019-11-04T08:12:31.077" LastActivityDate="2023-08-05T10:40:23.240" Title="On the light difference between morning and afternoon" Tags="|atmosphere|atmosphere-modelling|atmospheric-optics|" AnswerCount="5" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="13281" PostTypeId="1" CreationDate="2018-02-03T19:32:15.120" Score="4" ViewCount="467" Body="&lt;p&gt;It is well known that the majority of the world's mountain glaciers are retreating, but looking at a few LANDSAT images from the 1980s and today I am able to see glaciers that have retreated kilometers in that time frame, and others which have hardly changed at all within the same region. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am wondering what variables could be responsible for this? Bed rock lithology? Precipitation differences? Mountain slope? Etc.&lt;/p&gt;&#xA;" OwnerUserId="11934" LastEditorUserId="11908" LastEditDate="2018-02-06T18:27:23.527" LastActivityDate="2018-02-13T20:04:40.983" Title="What factors explain mountain glacier retreat variability?" Tags="|geology|geophysics|glaciology|ice|glacier|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13282" PostTypeId="2" ParentId="10149" CreationDate="2018-02-03T20:21:14.327" Score="1" Body="&lt;p&gt;I was personally looking for an answer to this question as well, and I found these sites very helpful.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The National Park Service Website:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Drumlins: &lt;a href=&quot;https://www.nps.gov/articles/drumlins.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nps.gov/articles/drumlins.htm&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Eskers: &lt;a href=&quot;https://www.nps.gov/articles/outwashplainsandeskers.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nps.gov/articles/outwashplainsandeskers.htm&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;And Landforms.Eu:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Kames: &lt;a href=&quot;http://www.landforms.eu/cairngorms/kame.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.landforms.eu/cairngorms/kame.htm&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;GEOL100:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;All: &lt;a href=&quot;https://www.geol.umd.edu/~jmerck/geol100/lectures/36a.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.geol.umd.edu/~jmerck/geol100/lectures/36a.html&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="12149" LastEditorUserId="5594" LastEditDate="2018-02-04T09:55:41.517" LastActivityDate="2018-02-04T09:55:41.517" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13284" PostTypeId="1" AcceptedAnswerId="13294" CreationDate="2018-02-04T17:43:39.247" Score="3" ViewCount="938" Body="&lt;p&gt;I need to do this for a planet that has uniform density, and a planet that has two layers. For the first part, I was given that the density was 550 kg/m³, so I made one column in an Excel spreadsheet that gave mass as a function of radius, then made another column that plugged that $M$ value into $g = \frac{GM}{r^2}$. Then I graphed my $g$ values against my radius, which gave a linear function. I'm not sure if that was the right approach, or of how to make a function for the planet that has more than one density. Does anyone have any ideas on this? &lt;/p&gt;&#xA;" OwnerUserId="12153" LastEditorUserId="94" LastEditDate="2018-02-05T11:40:53.350" LastActivityDate="2018-02-05T16:03:02.537" Title="How to graph gravity as a function of depth, given radius and density?" Tags="|geology|geophysics|planetary-science|homework|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13285" PostTypeId="1" CreationDate="2018-02-04T22:50:10.170" Score="8" ViewCount="362" Body="&lt;p&gt;Surface pressure given is &lt;em&gt;p&lt;/em&gt; = 1000 hPa. (the temperature along the atmosphere is constant (&lt;em&gt;T&lt;/em&gt; = −10 °C; hydrostatic equilibrium assumed). I tried using the hypsometric equation to find the height of the atmosphere's top and then going through that result, but it's not giving me the results I expect. I expect 500 hPa because I've seen the solution, but I obtained 700-ish hPa.&lt;/p&gt;&#xA;" OwnerUserId="6220" LastEditorUserId="725" LastEditDate="2018-02-12T23:22:44.493" LastActivityDate="2018-03-14T07:57:09.543" Title="How do I find the horizontal pressure level that divides the atmosphere into 2 layers of equal mass?" Tags="|meteorology|atmosphere|homework|" AnswerCount="4" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13286" PostTypeId="1" CreationDate="2018-02-05T01:47:37.190" Score="1" ViewCount="1312" Body="&lt;p&gt;I have this problem, and I am not sure where to start.  The only Airy equation in my text is $r_1= \frac{h_1 \cdot p_u}{p_s - p_u}$.  This doesn't seem to apply, or if it does it isn't obvious.  Is there some other equation I should be using?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A mountain range 4 km high is in Airy isostatic equilibrium. (10 points)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(a) During a period of erosion, a 2 km thickness of material is removed from the mountains. When the new isostatic equilibrium is achieved, how high are the mountains?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(b) How much material must be eroded to bring the mountains eventually down to the sea level? Use the crust and mantle densities of 2800 kg/m3 and 3300 km/m3, respectively.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;C) How High would they be if 10km of material were eroded away?&lt;/p&gt;&#xA;" OwnerUserId="12153" LastEditorUserId="725" LastEditDate="2018-02-05T12:12:22.403" LastActivityDate="2018-02-05T12:12:22.403" Title="What equation should I use in this isostasy problem?" Tags="|geology|geophysics|homework|geodynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13288" PostTypeId="2" ParentId="13286" CreationDate="2018-02-05T05:45:05.083" Score="1" Body="&lt;p&gt;As this is a homework problem I don't think I can answer what you have posted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think you have confused Airy's stress function with his concept of isotasy.  For some helpful information to get you pointed in the right way try the Wikipedia article on isostasy:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Isostasy&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Isostasy&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8513" LastEditorUserId="94" LastEditDate="2018-02-05T07:01:03.767" LastActivityDate="2018-02-05T07:01:03.767" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13289" PostTypeId="2" ParentId="13284" CreationDate="2018-02-05T06:00:33.443" Score="3" Body="&lt;p&gt;For each point as you descend into your planet you have a balance between gravity due to a solid sphere below you and &quot;counterbalanced&quot; by the gravity due to a hollow sphere of the planet above you.  This last is what is interesting because you are located at a point on the inside surface of the hollow sphere and need to come up with an integral that sums the gravity due to each direction in the hollow sphere. Each direction is a different distance away and a different thickness.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the center of the planet the inner sphere is gone and the outer one is uniform in each direction so the net gravity will be 0.  On the surface there is no outer sphere (assuming we can ignore the atmosphere) so g is totally calculated by a simple form of Newton's formula.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope this gives you enough clues to work out your solution.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2018-02-05T06:00:33.443" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13291" PostTypeId="2" ParentId="12459" CreationDate="2018-02-05T09:40:48.873" Score="3" Body="&lt;p&gt;To answer the $p_{CO_2}$ aspect of the question, here is a graph modified from &lt;a href=&quot;https://www.clim-past.net/9/525/2013/cp-9-525-2013.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kent &amp;amp; Muttoni (2013)&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/T8y4R.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/T8y4R.png&quot; alt=&quot;graph showing cretaceous to modern pCO2 variations&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is based on compilations from &lt;a href=&quot;https://doi.org/10.1073/pnas.0913188107&quot; rel=&quot;nofollow noreferrer&quot;&gt;Royer (2010)&lt;/a&gt; and &lt;a href=&quot;http://dx.doi.org/10.1038/ngeo1186&quot; rel=&quot;nofollow noreferrer&quot;&gt;Beerling &amp;amp; Royer (2011)&lt;/a&gt;, using a wide variety of proxies, but mostly fossil leaves stomata for the Cretaceous. It might be a bit outdated now but most articles out there do give values on the same range: ca. 400~500 ppm at the Cretaceous-Paleogene boundary and values fluctuating between 500 and 1500 ppm before that, with a maximum during the mid-Cretaceous. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for $p_{O_2}$, I couldn't find a recent compilation, but according to &lt;a href=&quot;http://dx.doi.org/10.1126/science.1260670&quot; rel=&quot;nofollow noreferrer&quot;&gt;Poulsen et al. (2015)&lt;/a&gt;, estimates for the Cenomanian (i. e. the high $p_{CO_2}$ period from the last graph) vary widely from 10% to (indeed as the other answer suggests) 32%. Here is the quote:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We focused on simulations of the Cenomanian, a mid-Cretaceous stage characterized by high $p_{CO_2}$ [e.g., (12)] and the warmest conditions of the past ~100 million years (13). Paleo-$p_{O_2}$ estimates inferred from stable-isotope carbon compositions indicate that the atmospheric percentage of $O_2$ was as low as 10 to 11% during this interval (7, 9), with one biogeochemical model indicating levels as high as 32.5% (6).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;References 7 and 9 are to &lt;a href=&quot;http://science.sciencemag.org/content/309/5744/2202.full&quot; rel=&quot;nofollow noreferrer&quot;&gt;Falkowski et al. (2005)&lt;/a&gt; and &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0016703713003906&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tappert et al. (2013)&lt;/a&gt;, while reference 6 is to &lt;a href=&quot;http://www.ajsonline.org/content/304/5/397.short&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bergman et al. (2004)&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2018-02-05T10:09:05.713" LastActivityDate="2018-02-05T10:09:05.713" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13292" PostTypeId="1" CreationDate="2018-02-05T10:10:13.530" Score="5" ViewCount="1068" Body="&lt;p&gt;I’m interested to know, because we live near the beach and all the metal on the outside of our house is corroded.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My dad says it was from the wind picking up spray from the surf, but I’m not so sure.&lt;/p&gt;&#xA;" OwnerUserId="11725" LastEditorUserId="94" LastEditDate="2018-02-08T15:44:06.467" LastActivityDate="2018-02-09T01:32:34.273" Title="When sea water evaporates does it carry small amounts of salt into the atmosphere?" Tags="|salinity|evaporation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13293" PostTypeId="1" CreationDate="2018-02-05T11:56:15.550" Score="3" ViewCount="145" Body="&lt;p&gt;I'm a GIS specialist with a good background in watershed hydrology and geomorphology theories. In a project, I should analyse coastal and inland catchments separately. I have some neighbourhood coastal catchments and want to use archydro tool in ArcGIS to create flow accumulation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the archydro manual, esri suggested the users &lt;strong&gt;append&lt;/strong&gt; coastal catchments (&lt;a href=&quot;http://downloads.esri.com/archydro/archydro/Doc/Overview%20of%20Arc%20Hydro%20terrain%20preprocessing%20workflows.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Overview of archydro terrain preprocessing workflows&lt;/a&gt; Page 8 of 13): &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Append Coastal Catchments. This is an optional step that should be done for larger DEM with a large portion of coastal areas – areas defined as not draining into the “streams”. This function defines coastal catchments and appends them to the catchment feature class.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Why a user should append coastal catchments while the catchments logically have separate drainage area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for advanced&lt;/p&gt;&#xA;" OwnerUserId="787" LastEditorUserId="787" LastEditDate="2018-02-06T07:11:06.447" LastActivityDate="2018-02-06T07:11:06.447" Title="Why Coastal catchments should be appended for watershed analysis (Archydro Suggestion)?" Tags="|hydrology|coastal|watershed|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13294" PostTypeId="2" ParentId="13284" CreationDate="2018-02-05T13:53:52.683" Score="5" Body="&lt;p&gt;As long as we deal with a spherically symmetric planet, the mass of the shell above you does not influence the observed gravity; the little mass close by exactly cancels the large amounts of mass far away (you would float inside a planet if it looked like a pingpong ball and had all its mass centered on the surface!), this is called Newton's Shell Theorem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can then compute $g$, acting as if the mass $M$ is concentrated at a point on the centre of the sphere. Thus, combining your knowledge of the mass $M$ underneath you, and the radius $r$ towards the center of this planet, you can compute the gravity field using the equation you give!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a constant density we have a volume $V=\frac{4}{3}\pi r^3$, thus mass $M=\rho_1 V$, and the gravity is given as $g(r)=\frac{GM}{r^2}=G\frac{4}{3}\pi r \rho_1$, linear like you found. For two layers, it is a sum of this first mass $M_1=\frac{4}{3}\pi_1R_1^3$ and second mass $M_2=\frac{4}{3}\pi_2(r-R_1)^3$ but ONLY when this mass is below you, i.e.&#xA;$$g^*(r) = \begin{cases}G\frac{4}{3}\pi \rho_1 r &amp;amp; r\leq R_1 \\ G\frac{4}{3}\pi( \rho_1\frac{R_1^3}{r^2}+\rho_2\frac{(r-R_1)^3}{r^2}) &amp;amp; r&amp;gt;R_1\end{cases}.$$&#xA;This should not be linear anymore due to the $R_1^3/r^2$ contribution!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Good luck!&lt;/p&gt;&#xA;" OwnerUserId="12155" LastEditorUserId="12155" LastEditDate="2018-02-05T16:03:02.537" LastActivityDate="2018-02-05T16:03:02.537" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13296" PostTypeId="2" ParentId="13270" CreationDate="2018-02-05T16:50:36.710" Score="2" Body="&lt;p&gt;This would actually be an interesting research project.  The ability to do a 3-D scan and model of a rock's shape in a manner that is fast enough to get a statistically meaningful number of rocks measured is relatively new.  Certainly you can easily name things that probably control the shape of rocks (lithology, mode of erosion, mode of transport, history of these things) but saying something about this in a quantitative way has not been done AFAIK.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think this is the sort of question that might result in surprising insights.  Or it might lead nowhere.  Certainly the question 'Does arid region erosion result in different shaped rocks than glacial erosion?'  answered in a quantitative way sounds worthwhile to me.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2018-02-05T16:50:36.710" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13297" PostTypeId="2" ParentId="13280" CreationDate="2018-02-05T17:20:47.897" Score="10" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;I am asking why the light of a clear day is not symmetrically changing centered at noon.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Trying to attribute this to a single cause misses the point. There are multiple causes. Other than lighting itself (i.e., the Sun angle), most aspects of the atmosphere are not symmetric about noon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The low on a clear day typically occurs right around sunrise (not midnight), while the high typically occurs hours after noon. Assuming a front is not passing through, relative humidity is typically highest in the hours around sunrise, lowest a few hours before sunset, roughly coinciding with the low and high temperatures. Atmospheric stability is high in the early morning on a clear calm day, low in the afternoon and evening. During weekdays, pollution oftentimes is at a minimum around 6 to 8 AM and a peak around 5 to 7 PM.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All of these can contribute to the effects you are seeing, plus other factors I did not list.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-02-05T17:20:47.897" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13298" PostTypeId="2" ParentId="13280" CreationDate="2018-02-05T17:46:37.090" Score="8" Body="&lt;p&gt;I believe the effects you are talking about are due to scattering by dust and water vapor in the atmosphere.  During the night winds are lower and wet areas don't dry out as fast as during the day.  Both of these mean that at the start of the day there is less dust and water in the atmosphere at a given location.  As the day progresses winds pick up (caused by heating from the sun) and the winds pick up dust and the amount of water held by the atmosphere increases due to warmer temperatures. During the middle of the day you don't see the effect of this in the light because the sun's rays are coming directly down through the atmosphere.  The sky will be a brighter blue due to the blue-selective scattering of rays that are not coming directly towards you.  In the late afternoon the slanting rays come through a much longer path through the atmosphere accentuating the scattering effect, resulting in redder light reaching you.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2018-02-05T17:46:37.090" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13301" PostTypeId="1" AcceptedAnswerId="13329" CreationDate="2018-02-05T22:37:27.427" Score="8" ViewCount="933" Body="&lt;p&gt;I want to analyze climate projection data for the different RCPs for a region in north western India, which has an arid climate. I chose MPI-ESM data downscaled with CORDEX. An example filename looks like this:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;pr_EAS-44_MPI-M-MPI-ESM-LR_rcp45_r1i1p1_CLMcom-CCLM5-0-2_v1_mon_208101-209012.nc&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;However, while all other variables like temperature, windspeed, relative humidity are on the right, scale, the precipitation is completely off.&#xA;The unit in the precipitation nc files is specified as kg m-2 s-1, which would equal a precipitation height of mm s-1. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since I have monthly data, multiplying the precipitation value with 86400 should get me to days, multiplying that with 30.42 should get me to months. If I now select a random year and do a cell-wise summation, I should get the total annual precipitation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The results are off by an order of magnitude. Here's a histogram of the cells showing total annual precipitation in mm for the EAS44 domain:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lOUnQ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lOUnQ.png&quot; alt=&quot;per-cell precipitation histogram of total annual precipitation in mm&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I read the data into a rasterbrick in R, which gave me the warning,&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Warning messages:&#xA;1: In .getCRSfromGridMap4(atts) : cannot process these parts of the CRS:&#xA;grid_north_pole_latitude=77.6100006103516; grid_north_pole_longitude=-64.7799987792969&#xA;2: In .getCRSfromGridMap4(atts) : cannot create a valid CRS&#xA;grid_north_pole_latitude=77.6100006103516; grid_north_pole_longitude=-64.7799987792969&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;... since it is on a curvilinear grid. I then subsetted the first twelve elements and calculated the values. &#xA;I somewhere read about scale factors and offsets in nc files, however, in my case I couldn't find a hint on something like that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: the header of the nc file:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;$ ncdump pr_EAS-44_MPI-M-MPI-ESM-LR_rcp45_r1i1p1_CLMcom-CCLM5-0-2_v1_mon_208101-209012.nc&#xA;netcdf pr_EAS-44_MPI-M-MPI-ESM-LR_rcp45_r1i1p1_CLMcom-CCLM5-0-2_v1_mon_208101-209012 {&#xA;dimensions:&#xA;    bnds = 2 ;&#xA;    rlon = 203 ;&#xA;    rlat = 167 ;&#xA;    time = UNLIMITED ; // (120 currently)&#xA;variables:&#xA;    char rotated_pole ;&#xA;        rotated_pole:grid_mapping_name = &quot;rotated_latitude_longitude&quot; ;&#xA;        rotated_pole:grid_north_pole_latitude = 77.61f ;&#xA;        rotated_pole:grid_north_pole_longitude = -64.78f ;&#xA;    double rlon(rlon) ;&#xA;        rlon:axis = &quot;X&quot; ;&#xA;        rlon:standard_name = &quot;grid_longitude&quot; ;&#xA;        rlon:long_name = &quot;longitude in rotated pole grid&quot; ;&#xA;        rlon:units = &quot;degrees&quot; ;&#xA;    double lon(rlat, rlon) ;&#xA;        lon:standard_name = &quot;longitude&quot; ;&#xA;        lon:long_name = &quot;longitude&quot; ;&#xA;        lon:units = &quot;degrees_east&quot; ;&#xA;    double rlat(rlat) ;&#xA;        rlat:axis = &quot;Y&quot; ;&#xA;        rlat:standard_name = &quot;grid_latitude&quot; ;&#xA;        rlat:long_name = &quot;latitude in rotated grid&quot; ;&#xA;        rlat:units = &quot;degrees&quot; ;&#xA;    double lat(rlat, rlon) ;&#xA;        lat:standard_name = &quot;latitude&quot; ;&#xA;        lat:long_name = &quot;latitude&quot; ;&#xA;        lat:units = &quot;degrees_north&quot; ;&#xA;    double time(time) ;&#xA;        time:units = &quot;days since 1949-12-01 00:00:00&quot; ;&#xA;        time:standard_name = &quot;time&quot; ;&#xA;        time:long_name = &quot;time&quot; ;&#xA;        time:calendar = &quot;proleptic_gregorian&quot; ;&#xA;        time:bounds = &quot;time_bnds&quot; ;&#xA;    double time_bnds(time, bnds) ;&#xA;        time_bnds:long_name = &quot;time bounds&quot; ;&#xA;    float pr(time, rlat, rlon) ;&#xA;        pr:standard_name = &quot;precipitation_flux&quot; ;&#xA;        pr:long_name = &quot;Precipitation&quot; ;&#xA;        pr:units = &quot;kg m-2 s-1&quot; ;&#xA;        pr:cell_methods = &quot;time: mean&quot; ;&#xA;        pr:coordinates = &quot;lon lat&quot; ;&#xA;        pr:grid_mapping = &quot;rotated_pole&quot; ;&#xA;        pr:missing_value = 1.e+20f ;&#xA;        pr:_FillValue = 1.e+20f ;&#xA;&#xA;// global attributes:&#xA;        :Conventions = &quot;CF-1.4&quot; ;&#xA;        :conventionsURL = &quot;http://www.cfconventions.org&quot; ;&#xA;        :creation_date = &quot;2017-09-07T11:34:35&quot; ;&#xA;        :contact = &quot;http://coastmod.hzg.de&quot; ;&#xA;        :experiment_id = &quot;rcp45&quot; ;&#xA;        :driving_model_id = &quot;MPI-M-MPI-ESM-LR&quot; ;&#xA;        :driving_model_ensemble_member = &quot;r1i1p1&quot; ;&#xA;        :driving_experiment_name = &quot;rcp45&quot; ;&#xA;        :frequency = &quot;mon&quot; ;&#xA;        :institute_id = &quot;CLMcom&quot; ;&#xA;        :rcm_version_id = &quot;v1&quot; ;&#xA;        :model_id = &quot;CLMcom-CCLM5-0-2&quot; ;&#xA;        :project_id = &quot;CORDEX&quot; ;&#xA;        :CORDEX_domain = &quot;EAS-44&quot; ;&#xA;        :product = &quot;output&quot; ;&#xA;        :experiment = &quot;rcp45&quot; ;&#xA;        :driving_experiment = &quot;MPI-M-MPI-ESM-LR, rcp45, r1i1p1&quot; ;&#xA;        :Institution = &quot;Helmholtz-Zentrum Geesthacht&quot; ;&#xA;        :references = &quot;http://cordex.clm-community.eu&quot; ;&#xA;        :institution_run_id = &quot;r15m4r4&quot; ;&#xA;        :institution_data_path = &quot;/hpss/arch/gg0302/g260068/CORDEX-EA/r15m4r4&quot; ;&#xA;        :source = &quot;Climate Limited-area Modelling Community (CLM-Community)&quot; ;&#xA;        :title = &quot;CLMcom-CCLM5-0-2 model output prepared for CORDEX rcp45&quot; ;&#xA;        :comment = &quot;Please use the following reference for this climate data: Climate projection performed by Helmholtz-Zentrum Geesthacht in the Climate Limited-area Modelling Community (CLM-Community)&quot; ;&#xA;data:&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;This is the R code I used for generating the data in the plot:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;library(raster)&#xA;library(purrr)&#xA;library(dplyr)&#xA;&#xA;raster_brick &amp;lt;- brick('original_data/pr_EAS-44_MPI-M-MPI-ESM-LR_rcp45_r1i1p1_CLMcom-CCLM5-0-2_v1_mon_205101-206012.nc')*86400*30.42&#xA;# map the first twelve raster into a list of rasters and merge them into a new rasterbrick&#xA;first_year_rasters &amp;lt;- 1:12 %&amp;gt;% map(~ raster_brick[[.]]) %&amp;gt;% brick&#xA;# cell-wise sum&#xA;sum_raster &amp;lt;- sum(first_year_rasters)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;EDIT: Here are two screenshots of ncview of monthly data for 2053&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XmlX8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XmlX8.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RbLsf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RbLsf.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The unit clearly is stated as kg per square meter and second. The datapoint for July 2053 is at about 0.00375 kg m-2 -s1, that equals a monthly precipitation of 0.00375*86400*30.42 = 9.9 meters ...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a screenshot from the 2006-2100 monthly precipitation values from RCP4.5, CMIP5, MPI-ESM-MR model. I used the cdo operator -yearsum on it, so these should correspond to the annual precipitation in kg m-2 s-1. Multiplied with 86400*30.42 I still arrive at the order of magnitude of several meters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Nz3UU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Nz3UU.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11466" LastEditorUserId="11466" LastEditDate="2018-02-07T16:31:06.520" LastActivityDate="2018-02-09T09:57:31.080" Title="Confusion with precipitation values in CORDEX MPI-ESM rcp data" Tags="|precipitation|climate-models|climatology|gis|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13302" PostTypeId="1" CreationDate="2018-02-06T00:09:22.227" Score="5" ViewCount="224" Body="&lt;p&gt;On earth nutrients flow from the land to the ocean. Life on oceans need those nutrients to trive.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was trying to think how an ocean world might support life if there was no land to provide the necessary bootstapping nutrients.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any thoughts?&lt;/p&gt;&#xA;" OwnerUserId="12160" LastEditorUserId="11908" LastEditDate="2018-02-07T02:21:15.240" LastActivityDate="2018-02-12T18:26:05.343" Title="How would a world entirely covered in oceans get the nutrients to support life?" Tags="|ocean|oceanography|planetary-science|biogeochemistry|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13303" PostTypeId="2" ParentId="13281" CreationDate="2018-02-06T00:24:10.133" Score="3" Body="&lt;p&gt;There is indeed a large variability in glacier behavior, even between neighboring ones. If you look harder, you will even find advancing glaciers right beside others receding quickly. There are multiple factors that can explain such variability, I will list the most important ones:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;strong&gt;Orographic control&lt;/strong&gt;: A climatic change can affect differently neighbouring glaciers. If the wind, air moisture or temperature changes, the corresponding changes in precipitation or solar irradiation can vary on different areas of a mountain massif due to its topography, therefore affecting differently each glacier. A classic and illustrative example is the orographic precipitation illustrated by the figure below. It explains why the windward side of a mountain range could have bigger glaciers than the other. Now, in the case of an increase in -let's say- temperature and air moisture content (that usually come together), the associated  increase in precipitation might benefit snow accumulation in one side more than the other, while the temperature will affect both more or less in the same way. Leading to leeward  glaciers receding faster than windward ones. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/7JXsN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7JXsN.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Topographic controls&lt;/strong&gt;: All glaciers flow downhill, and the speed of such flow depends on the resistance the bedrock, valley walls, moraines, etc. A glacier that is in steady state (i.e. not advancing nor receding) is in balance between snow accumulation in its upper reaches and melting in its lower areas. Even if there is no changes in accumulation or melting, this balance can be broken if the speed of the glacier changes. If the ice is taken faster from its cold head to the warm front, that will increase the melting and more snow would be needed to offset the additional melting.&#xA;Most of the resistance to flow is provided by constrictions of the valley walls or protrusions of the bed. As in the figure below (from &lt;a href=&quot;https://www.gvsu.edu/rmsc/interchange/z2011-september-connections-563.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;), taking a floating ice tongue as example (a.k.a. ice shelf) where most of the resistance to flow comes from the bed protrusion below the &quot;ice rise&quot;, in this case such protrusion is called a &quot;pinning point&quot;.&#xA;Now, going back to your question: Even if two glaciers that are receding at the same rates, eventually one could recede behind a constriction, therefore its speed will increase, pushing it further out of balance, so it will start loosing mass faster than its neighbor and at some point that will show up as a more pronounced shrinking in images like the ones you were studying.&#xA;In the case of ice shelves (like the one in the figure), loosing contact with a pinning point can lead to the collapse and breakup of large sections of the floating tongue in very quick and dramatic events.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qL91x.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qL91x.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Reaction time scales&lt;/strong&gt;: Neighbouring glaciers can have huge differences in mass. And that means that they don't react with the same speed environmental changes. In a very small glacier, you will see advance after a few years of high accumulation. However, in a very large glacier, a few years of high accumulation doesn't make much of a difference. And the glacier can still recede after such events, perhaps due to a few decades of low accumulation that happen a hundred years ago.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Area is not volume&lt;/strong&gt;: What you see in the images are changes in area not volume. So even if two glaciers are loosing the same amount of mass per year. If one is thinner than the other, you will see that the thicker one shrink less that the other.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Hypsometry&lt;/strong&gt;: It  refers to the distribution of values of surface elevation of a glacier. For example if two of the glaciers you are observing span from 1,500 to 2,500m of elevation, but one of them have 90% of its surface above 2,000m of elevation, and the other only a 30%. You will observe that a change in temperature that push the average freezing line from 1,800m to 2,000m will affect the second glacier much more than the first, because it will suffer a larger increase in the fraction of its surface exposed to melting temperatures.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Surging glaciers&lt;/strong&gt;: Some glaciers undergo what is call a &lt;a href=&quot;https://en.wikipedia.org/wiki/Surge_(glacier)&quot; rel=&quot;nofollow noreferrer&quot;&gt;glacial surges&lt;/a&gt;. They show a cyclical behavior in which they advance very quick over few years and then recede slowly over decades to then start over again. I won't go in detail about this process that is very complex and still poorly understood. But in the images you observe, they might be some variability also to the presences of glacier surges. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Other factors could be more complex weather redistribution patterns, bed topography, bedrock lithology, basin divide migration, frontal wasting (calving) for lake and marine terminating glaciers, etc.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-02-13T20:04:40.983" LastActivityDate="2018-02-13T20:04:40.983" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13304" PostTypeId="2" ParentId="13302" CreationDate="2018-02-06T01:36:05.573" Score="7" Body="&lt;p&gt;If the planet is geologically/volcanically active &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydrothermal_vent&quot; rel=&quot;noreferrer&quot;&gt;hydrothermal vents&lt;/a&gt; are a way by which nutrients, in the way of minerals and chemicals, can enter the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Certain types of bacteria can consume the minerals and such bacteria form the base of a food chain. Also, the heat from the hot water can provide energy to life forms.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2018-02-06T02:23:13.460" LastActivityDate="2018-02-06T02:23:13.460" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13306" PostTypeId="1" AcceptedAnswerId="16268" CreationDate="2018-02-06T18:28:16.677" Score="3" ViewCount="316" Body="&lt;p&gt;How long would it take for a store bought rubber balloon filled in space with air to fall from space just outside the atmosphere and touch ground? Would it Pop?   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Added after comments: Ideally you would like to have a balloon filled with 14 PSI before it was dropped so that way it maintains its shape all the way down to the ground. But being a normal party balloon has its problems. It would only take one PSI of ambient air to fill a party balloon in space and any more than that it would pop.&#xA;I didn't take in consideration on how temperature would affect the rubber. On the sunny side it would be well above the melting point of the rubber. On the freezing shadow side of the Earth side the rubber would freeze becoming brittle and break.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Temperature outside would the pressure of falling through the atmosphere pop the balloon?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yzPTS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yzPTS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2019-08-10T19:31:13.507" LastActivityDate="2019-08-10T19:31:13.507" Title="A balloon falling from space?" Tags="|atmosphere|thermodynamics|gravity|" AnswerCount="1" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="13307" PostTypeId="1" CreationDate="2018-02-06T20:09:56.637" Score="5" ViewCount="98" Body="&lt;p&gt;Such as in 3D simulations of vehicule crashes but this time with huge rocks or bodies of water (continental plates). I need to be able to set the properties of the material (density, size etc) and see what happens according to physic laws.&lt;/p&gt;&#xA;" OwnerUserId="160" LastEditorUserId="595" LastEditDate="2018-02-06T21:17:35.767" LastActivityDate="2018-02-06T21:17:35.767" Title="On which software can I simulate landmass collisions?" Tags="|plate-tectonics|land-surface|crust|simulation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13309" PostTypeId="1" CreationDate="2018-02-06T22:12:38.030" Score="2" ViewCount="2685" Body="&lt;p&gt;Which type of convergent boundary creates the tallest mountains?&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Continental-Continental &lt;/li&gt;&#xA;&lt;li&gt;Ocean-Ocean&lt;/li&gt;&#xA;&lt;li&gt;Ocean-Continental&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="12169" LastEditorUserId="11908" LastEditDate="2019-04-06T20:07:18.800" LastActivityDate="2019-04-06T20:07:18.800" Title="Which type of convergent boundary creates the tallest mountains?" Tags="|geology|geophysics|plate-tectonics|structural-geology|mountain-building|" AnswerCount="1" CommentCount="2" ClosedDate="2018-02-09T11:01:44.797" ContentLicense="CC BY-SA 3.0" />
  <row Id="13310" PostTypeId="1" CreationDate="2018-02-06T22:57:26.053" Score="3" ViewCount="1028" Body="&lt;p&gt;What structures form from the melting of subducting plates? &#xA;Plutons, Accretionary wedges, Deep sea trenches, Faults?&lt;/p&gt;&#xA;" OwnerUserId="12169" LastEditorUserId="11908" LastEditDate="2019-03-11T21:00:25.717" LastActivityDate="2019-03-11T21:00:25.717" Title="What structures form due to the melting of subducting plates?" Tags="|geology|geophysics|plate-tectonics|tectonics|" AnswerCount="1" CommentCount="2" ClosedDate="2018-02-09T09:08:50.857" ContentLicense="CC BY-SA 3.0" />
  <row Id="13311" PostTypeId="2" ParentId="13302" CreationDate="2018-02-07T00:45:00.010" Score="6" Body="&lt;p&gt;On an &lt;a href=&quot;https://en.wikipedia.org/wiki/Ocean_planet&quot; rel=&quot;nofollow noreferrer&quot;&gt;ocean planet&lt;/a&gt;, nutrients can come either from space or from the bottom of the ocean, where they can leak from the crust trough different processes, perhaps with the help of submarine volcanoes or hydrotermal vents if the planet is geologically active. The latter is likely to be the case, because assuming you meant water oceans, to have that much water at the right temperature to keep it liquid, the planet will most likely be a &lt;a href=&quot;https://en.wikipedia.org/wiki/Circumstellar_habitable_zone#Habitable_super-Earths&quot; rel=&quot;nofollow noreferrer&quot;&gt;super earth&lt;/a&gt; orbiting a small star, like &lt;a href=&quot;https://en.wikipedia.org/wiki/Kepler-22b&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kepler-22b&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/yk6KJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yk6KJ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Such large planets will most likely cooldown slow enough to provide many billions of years of volcanic and tectonic activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, from Earth's oceans, we know that the most biologically productive areas are associated to landmasses, because they force upwelling and due to the nutrients that rivers and winds carry from them.&#xA;So perhaps more than the original source of the nutrients, we should figure out how those nutrients will cycle to sustain life: In an ocean world, the productivity would be limited by the strength of the ocean vertical currents, that could bring nutrients from the bottom of the ocean to shallow waters were sunlight provides the planet's largest source of energy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At some point, ocean worlds were very good candidates to host life, but now it looks it might not be the case: Due to the quick dissolution of chemical gradients on an ocean. The leading theory for the origin of life is that of the &quot;&lt;a href=&quot;https://blogs.scientificamerican.com/thoughtomics/did-life-evolve-in-a-warm-little-pond/&quot; rel=&quot;nofollow noreferrer&quot;&gt;warm little pond&lt;/a&gt;&quot;, an environment that wouldn't exist in an ocean planet.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/C3ZWT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/C3ZWT.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another problem facing life on super earth ocean worlds, is that with the pressures found at the bottom of the ocean, the ocean floor will probably get covered in &lt;a href=&quot;https://en.wikipedia.org/wiki/Amorphous_ice#High-density_amorphous_ice&quot; rel=&quot;nofollow noreferrer&quot;&gt;HDA&lt;/a&gt; a dense form of water ice. Creating a layer that would difficult the exchange of chemical compounds and heat between the crust/mantle and the ocean, hampering the formation and sustainability of life. On the bright side, if such planets orbit a small star, they will have plenty of time to form life, as small stars live much longer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in addition to ask if an ocean world can support life, it is also interesting to ask if life is likely to form in such worlds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is a possibility that in such worlds life is confined to hydrotermal vents, but from your question I assume you are pondering the possibility of an ocean full of life, like the ones on Earth.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-02-12T18:26:05.343" LastActivityDate="2018-02-12T18:26:05.343" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13312" PostTypeId="2" ParentId="13310" CreationDate="2018-02-07T00:56:11.833" Score="5" Body="&lt;p&gt;The subducting plate never really melt. It just gets recycled into the mantle (the &lt;a href=&quot;https://en.wikipedia.org/wiki/Asthenosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;Asthenosphere&lt;/a&gt; to be more precise), which is in solid state. It is plastic and deformable enough to allow convection flows, but it is solid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Beside more mantle, something that forms from the subducting plate is magma. The water contained in the subducted slab (that was once ocean floor) can lower the melting point of the mantle and allow it to melt and form magma. The magma is liquid and less dense than the surrounding mantle, therefore it rises through it, and then through the continental plate. Once there it can create plutons, batholiths and feed volcanoes if it make it all the way to the surface.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Jsn5k.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Jsn5k.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;But what melts is mostly the mantle mixed with water from the subducting plate, not the subducting plate itself.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-02-07T14:34:07.867" LastActivityDate="2018-02-07T14:34:07.867" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13313" PostTypeId="2" ParentId="13309" CreationDate="2018-02-07T01:15:03.717" Score="2" Body="&lt;p&gt;The type of convergent boundaries is not the only factor. From the current configuration of the world one could be tempted to say that Continental-Continental collisions would form the tallest mountains. And they are indeed the most dramatic tectonic collisions and they formed the Himalayas, that are almost 2,000 m taller than any other mountain on Earth. However, the india-Asia collision wasn't any collision it was the most dramatic collision in a long time with convergence rates of &lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2010JB008051/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;16 cm/year&lt;/a&gt;, way more than any current convergence rate.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/raM60.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/raM60.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;From &lt;a href=&quot;https://pubs.usgs.gov/gip/dynamic/himalaya.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, the convergence rate is also a very important factor. The tallest mountain outside the Himalayas is mount Aconcagua in an oceanic-continental boundary. With a convergence rate of about 6 cm/year, and that have been &lt;a href=&quot;https://www.researchgate.net/publication/227232445_Subduction_Erosion_-_the_Normal_Mode_of_Fore-Arc_Material_Transfer_along_the_Chilean_Margin/figures?lo=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;below 16 cm/year at least for the last 22 million years&lt;/a&gt;.&#xA;So it is difficult to say how tall would be Mount Aconcagua if you speed up the convergence rate between Nazca and South America plates by 260%.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't think there is a definite answer to your question, unless you constrain other factors, like convergence rate, plates thicknesses, etc.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-02-07T02:05:34.120" LastActivityDate="2018-02-07T02:05:34.120" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13314" PostTypeId="1" CreationDate="2018-02-07T05:53:55.140" Score="4" ViewCount="28" Body="&lt;p&gt;In order to accurately perform weather forecasts during large wildfire events, weather models must include the smoke.  Smoke reflects sunlight back to space, decreasing the light absorbed by the surface of the Earth.  If the smoke is not considered in weather models, temperature can be greatly overestimated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some models, such as WRF-Chem, do a fine job of taking care of this problem if good predictions of smoke are available.  However, WRF-Chem is too computationally expensive to be used as an operational weather forecast model.  WRF (without Chemistry) is able to include smoke information.  However, I cannot find any height-resolved smoke forecasts that go out far enough in time (e.g. 72 hours) so that they can be used in a weather forecast framework.  I've considered &lt;a href=&quot;https://www.airfire.org/data/bluesky-daily/&quot; rel=&quot;nofollow noreferrer&quot;&gt;BlueSky&lt;/a&gt;, but only surface-smoke is given.  I've also considered &lt;a href=&quot;https://weather.gc.ca/firework/index_e.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;FireWork&lt;/a&gt;, but those forecasts only go out 48 hours. Are there smoke forecasts that are height-resolved and go out at least 72 hours? &lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2018-02-07T05:53:55.140" Title="What 3-day smoke forecasts are height-resolved?" Tags="|temperature|weather-forecasting|wildfire|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13316" PostTypeId="2" ParentId="9826" CreationDate="2018-02-07T22:26:42.757" Score="2" Body="&lt;p&gt;Of course there is, and in not that complex. Is called the &lt;a href=&quot;https://en.wikipedia.org/wiki/Heat_equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;heat equation&lt;/a&gt;, and is a type of &lt;a href=&quot;https://en.wikipedia.org/wiki/Diffusion_equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;diffusion equation&lt;/a&gt; that can be easily solved numerically or analytically in some simple geometries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you don't want to get involved in the math, you can use one of mane heat transfer simulation software, there are even online version that run in your browser like &lt;a href=&quot;http://energy.concord.org/energy2d/compare-capacity.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Energy2D&lt;/a&gt;, in which you can configure the geometry and thermal properties of your materials and let the simulation run.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The screenshot below is a problem with the geometry you suggest. But you would need to set the correct thermal properties of air and basalt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are looking for a customized equation, you have to constrain the geometry of the problem. For instance: the cooling of a laterally infinite layer of material at 1000 °C of thickness X with a medium (air in your case) above it, at constant temperature of 10°C and a medium below it (bedrock) at initial temperature 5°C, you can look at engineering formulas handbooks, or post the question on the Engineering or Math Stack Exchange sites. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/t8IjL.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/t8IjL.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-02-07T22:26:42.757" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13320" PostTypeId="1" AcceptedAnswerId="13328" CreationDate="2018-02-08T17:13:32.343" Score="9" ViewCount="759" Body="&lt;p&gt;When pondering the hypothesis of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Iron_catastrophe&quot; rel=&quot;noreferrer&quot;&gt;Iron catastrophe&lt;/a&gt;, that seem to be widely accepted nowadays. It surprises me that currently the crust still contain a significant amount of Iron (&lt;a href=&quot;https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements#Crust&quot; rel=&quot;noreferrer&quot;&gt;5.6% in weight&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I wonder if that much Iron is what didn't sink in the Iron catastrophe (just because the process wasn't perfect), or it can be explained by slow reloading with iron transported from the outer core and mantle to the crust trough convection and volcanic activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or perhaps it cam from other sources like meteorites?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pSpKE.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pSpKE.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;Picture from &lt;a href=&quot;http://astro.hopkinsschools.org/course_documents/earth_moon/earth/geologic_time/iron_catastrophe.htm&quot; rel=&quot;noreferrer&quot;&gt;astro.hopkinsschools.org&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-02-08T19:12:10.820" LastActivityDate="2018-02-09T09:20:36.600" Title="Is the iron on Earth's crust a leftover of the Iron catastrophe, or it was brought back by volcanoes?" Tags="|geophysics|geochemistry|volcanology|core|iron|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13322" PostTypeId="1" CreationDate="2018-02-08T19:48:36.937" Score="1" ViewCount="248" Body="&lt;p&gt;What do you call the leading waves and activity leading before a large wave?&lt;/p&gt;&#xA;" OwnerUserId="12182" LastActivityDate="2018-02-09T12:00:17.277" Title="Searching for common wave vocabulary" Tags="|ocean|waves|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13323" PostTypeId="2" ParentId="13322" CreationDate="2018-02-09T00:02:54.823" Score="4" Body="&lt;p&gt;Here is what I found if useful for others -&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Oceanic Wave Clarification&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wave position in space (x,y) and in time (t) are different concepts&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ocean waves in &lt;em&gt;time&lt;/em&gt; are a vertical oscillation generated most often from surface winds creating a circulation (eddy). There are no 'leading waves' to a 'big wave' rather simply a continual progression in size.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ocean waves in &lt;em&gt;space&lt;/em&gt; are generated from the simple motion of the wind. As the depth decreases the energy density of the wave increases, increasing the wave amplitude&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Illustration&lt;/strong&gt; &lt;a href=&quot;https://www.quora.com/When-do-waves-stop-forming-in-the-ocean-Is-there-a-specific-area-in-the-ocean-where-the-water-is-calm-and-then-waves-form-in-two-separate-directions-from-that-area-of-calmness-What-elements-and-factors-contribute-to-waves-forming&quot; rel=&quot;nofollow noreferrer&quot;&gt;(1)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/24v7F.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/24v7F.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Common Vocabulary&lt;/strong&gt; (if useful)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qQD5G.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qQD5G.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;(1) &lt;a href=&quot;https://www.quora.com/When-do-waves-stop-forming-in-the-ocean-Is-there-a-specific-area-in-the-ocean-where-the-water-is-calm-and-then-waves-form-in-two-separate-directions-from-that-area-of-calmness-What-elements-and-factors-contribute-to-waves-forming&quot; rel=&quot;nofollow noreferrer&quot;&gt;Quora - &gt;When do waves stop forming in the ocean?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;(2) &lt;a href=&quot;http://hyperphysics.phy-astr.gsu.edu/hbase/Waves/watwav2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hyperphysics - Ocean Waves&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="12182" LastEditorUserId="12182" LastEditDate="2018-02-09T12:00:17.277" LastActivityDate="2018-02-09T12:00:17.277" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13324" PostTypeId="2" ParentId="13292" CreationDate="2018-02-09T01:32:34.273" Score="3" Body="&lt;p&gt;Listen to your father ! Yes droplets of spray are carried on the wind several miles . There are any number of corrosion tables listing atmospheric corrosion more severe on sea coasts.  Much of the testing was / is being done at Kure Beach ( N or S ) Carolina.  &lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2018-02-09T01:32:34.273" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13325" PostTypeId="1" CreationDate="2018-02-09T06:22:58.057" Score="1" ViewCount="78" Body="&lt;p&gt;It is an unusual year where I'm at, I'd like to go and see similar climatological years for the north america, more particularly for average pressure, maybe 500mb or 700mb. How would I do this  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: Regional or State would be fine. Average pressure on a 1 month or seasonal basis.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Context: I am simply trying to compare the year, if there is a better way to do this than pressure, even temperature and precip would be nice. I'm looking to find simmilarities between years on a regional level. A map of average pressure on a seasonal basis would be awesome. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Region: North America regional, but the finer resolution the better&lt;/p&gt;&#xA;&#xA;&lt;p&gt;License: I'd like this to be free.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Format: Any format is acceptable.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Non-answers: I'm looking for more then the NOAA Climatic Data Center can provide. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Authority: Any source is acceptable  &lt;/p&gt;&#xA;" OwnerUserId="6949" LastEditorUserId="6949" LastEditDate="2018-02-28T06:19:35.933" LastActivityDate="2018-02-28T06:19:35.933" Title="Where can I find climate analogs?" Tags="|meteorology|climatology|" AnswerCount="0" CommentCount="2" ClosedDate="2018-02-10T19:16:40.977" ContentLicense="CC BY-SA 3.0" />
  <row Id="13327" PostTypeId="1" AcceptedAnswerId="16194" CreationDate="2018-02-09T09:19:27.507" Score="11" ViewCount="1420" Body="&lt;p&gt;This is well known to everyone that clouds carry electric charges and cumulonimbus clouds contain huge amount of electricity. It is also known from Maxwell's equations that moving particles induce magnetic field around them. I am sorry if I am missing any concept here but I have a question,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Should there also be a magnetic field around cumulonimbus clouds due&#xA;  to the presence and motion of charged particles in them?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Edit:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to know about field studies reporting the intensity of the magnetic field in different cloud systems. I am interested in knowing about cold clouds as the interaction of solid hydrometeors could be prominent in them. I also want to know if the intensity is sufficient enough to have an interaction with magnetic field of earth. I see recent modeling studies are being performed on electric fields, but the mention of magnetic field is still missing in them. &lt;/p&gt;&#xA;" OwnerUserId="11162" LastEditorUserId="11162" LastEditDate="2019-02-07T13:22:20.347" LastActivityDate="2019-02-11T12:49:35.907" Title="Electricity in clouds and induced magnetism" Tags="|atmosphere|clouds|electromagnetism|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="13328" PostTypeId="2" ParentId="13320" CreationDate="2018-02-09T09:20:36.600" Score="9" Body="&lt;p&gt;Not all the iron sank to the core. Have a look at my answer to a previous question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/7076/725&quot;&gt;https://earthscience.stackexchange.com/a/7076/725&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your question is similar, but coming the other way. You're asking - why is there iron in the mantle/crust?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer is that there was enough oxygen left in the Earth after oxidising the other lithophile elements (Si, Mg, Al, Ca, etc) to oxidise some of the iron. And when iron is oxidised - it is not a metal anymore, but instead incorporated into rock forming minerals like olivine and pyroxenes.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-02-09T09:20:36.600" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13329" PostTypeId="2" ParentId="13301" CreationDate="2018-02-09T09:57:31.080" Score="8" Body="&lt;h2&gt;TLDR;&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The precipitation values (and possibly some other variables; see below) need to be divided by 24.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Background&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The global attributes of the netCDF file in the question provide an URL to a description page: &lt;a href=&quot;http://coastmod.hzg.de&quot; rel=&quot;noreferrer&quot;&gt;coastmod.hzg.de&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From that URL a user should be redirected to &lt;a href=&quot;http://wiki.coast.hzg.de/display/MD&quot; rel=&quot;noreferrer&quot;&gt;wiki.coast.hzg.de/display/MD&lt;/a&gt; (access at 9th Feb 2018). Unfortunately, the redirect does not work in the moment due to an internal server error (status: February 2018).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On &lt;a href=&quot;http://wiki.coast.hzg.de/display/MD&quot; rel=&quot;noreferrer&quot;&gt;wiki.coast.hzg.de/display/MD&lt;/a&gt; a comment is provided for the &lt;strong&gt;CORDEX-EastAsia&lt;/strong&gt; data set -- reading:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;pr (precipitation rate)&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Due to a post processing error all precipitation rates have to be divided by a factor of 24 to get the right dimension kg m-2 s-1.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The following parameters may also be affected:&#xA;  evspsbl,mrro,mrros, prc, prhmax, prsn, snm&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2018-02-09T09:57:31.080" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13331" PostTypeId="1" AcceptedAnswerId="13334" CreationDate="2018-02-09T19:25:00.773" Score="12" ViewCount="11996" Body="&lt;p&gt;Why are deserts famous for fossils? Is it a coincidence? Some examples:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://news.nationalgeographic.com/2017/03/ancient-egypt-catfish-fossil-palaeontology-science/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Giant Catfish Fossil Found in Egyptian Desert&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.bbc.com/news/science-environment-26343894&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chile's stunning fossil whale graveyard explained&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.livescience.com/5217-giant-dinosaur-fossil-sahara-desert.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Giant Dinosaur Fossil Found in Sahara Desert&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12045" LastEditorUserId="12045" LastEditDate="2018-03-06T20:41:44.760" LastActivityDate="2018-03-06T20:41:44.760" Title="Why are many fossils found in deserts?" Tags="|paleontology|fossils|desert|" AnswerCount="4" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13332" PostTypeId="2" ParentId="13331" CreationDate="2018-02-09T19:46:57.770" Score="20" Body="&lt;p&gt;Bones don't last very long in jungles. Or in forests. Or almost anywhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fossils are the consequence of one highly unlikely fluke after another. Darwin himself commented on this. It takes just-right circumstances to have the bones of a recently deceased animal not be eaten by scavengers or turned into rot by bacteria. It takes yet another set of just-right circumstances for those bones to turn into fossils. It takes yet another set of just-right circumstances for those fossils to be brought back to surface level. It takes yet one more set of just-right circumstances for those nearly exposed fossils to survive the ravages of time and weathering.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The last coincidence is where deserts come into play. Water is an extremely powerful weathering agent. The key characteristic of deserts is an extreme lack of water. Fossils are much more likely to survive the savages of time without that weathering by water.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-02-09T19:46:57.770" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13333" PostTypeId="2" ParentId="13256" CreationDate="2018-02-09T20:47:34.300" Score="5" Body="&lt;h2&gt;Some simplifying assumptions&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;This is quite a broad and complex question to answer, so I'm going to simplify it shamelessly to make it a little more answerable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Firstly, there are a huge number of different plastics with a huge variety of physical characteristics. You mention that you're interested in ‘the most common type of plastics’, so I'm going to ignore exotic, high-temperature specialist polymers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly, you specified that by ‘destroy’, you mean ‘chemically convert the plastic to a molecular form that is found in &quot;nature&quot;’. This could be tricky to guarantee completely: to be really sure you'd have to do a thorough analysis of all the molecular structures in the altered plastic, and make sure that none of them occur in nature. I'm going to reference research on pyrolysis of plastics which classifies end products as gas, wax, oil, and char, and assume that these products contain little or no material which couldn’t be found in nature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thirdly, I’m going to ignore metamorphic conditions other than temperature. Temperature will, I’m fairly sure, have the biggest effect on the breakdown of plastics. The chemical environment might make the plastic break down more quickly (by providing reactants), but I don’t think that it will make the plastic break down any more slowly than it would at the same temperature in an inert atmosphere or vacuum. I’ll also ignore any pressure effects.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Grades of metamorphism&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Here’s a helpful diagram of metamorphic facies, temperatures, and pressures (source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Metamorphic_Facies.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikimedia&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4FKhA.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4FKhA.jpg&quot; alt=&quot;Metamorphic facies&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The chart cuts off at 900°C, by which point the rock will generally be melting, putting it into the igneous rather than metamorphic category.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Effects of heating on common plastics&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Fortunately for this question, efforts to dispose of waste plastic have led to a lot of research on the effects of heating. Williams and Williams (1997) is a particularly useful reference. They report the effects of heating a sample of mixed plastic waste (low- and high-density polyethylene, polypropylene, polystyrene, polyvinyl chloride, and polyurethane) in an inert nitrogen atmosphere at temperatures ranging from 500°C to 700°C. Here’s what they got out of it (yields are in percentages):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/slfSp.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/slfSp.png&quot; alt=&quot;Table of product yields&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(I assume that there's a typo somewhere in the 650°C column, since it implies a 110.5% yield.) The yield is 78.91% at 550°C, so maybe we could expect some identifiable plastic residue (though probably no actual plastic) to remain at that point. By 600°C, there's already a 95.51% yield; unfortunately the missing char figures prevent us from quantifying the yield at higher temperatures, but it seems likely that we’d be approaching 100% by 700°C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are a few pages of analyses of the products, but they’re mainly focused on their suitability as fuels rather than whether they’re found in nature. Considering the &lt;a href=&quot;https://en.wikipedia.org/wiki/Petroleum#Composition&quot; rel=&quot;nofollow noreferrer&quot;&gt;wide variety of compounds found it crude oil&lt;/a&gt;, I think it’s plausible that all the plastic pyrolysis products have naturally occurring counterparts, but it would be a significant research project to establish this beyond all doubt.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Putting it together&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Referencing the pyrolysis temperatures back to the metamorphic facies, it looks as though the amphibolite facies corresponds reasonably to the range over which common plastics are completely, or near-completely, decomposed by temperature. So, when the aliens land in a few million years and start investigating the Anthropocene, they might well find some of our old rubbish in prehnite-pumpellyite (P-P) facies rocks, but there won't be much to see in the granulites. Here are some examples of metamorphic rocks from those grades.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kQScL.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kQScL.jpg&quot; alt=&quot;prehnite-pumpellyite facies&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;Liberty Gulch Broken Formation, a prehnite-pumpellyite facies metasandstone. Source: Raymond and Berro (2015).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fFixo.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fFixo.jpg&quot; alt=&quot;amphibolite facies&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;Amphibolite facies (staurolite zone) metasediments from the Scottish Dalradian. Source: &lt;a href=&quot;https://www.earth.ox.ac.uk/~oesis/teaching/metageol/Collisions/Dalradian/index.html#&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dave Waters, &lt;em&gt;Dalradian Metamorphism&lt;/em&gt; album&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RambQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RambQ.jpg&quot; alt=&quot;granulite facies&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;Strongly deformed high- to medium-pressure pelitic granulites from the Qianlishan Complex. Source: Yin et al. (2014).&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Loren A. Raymond, David A. Bero (2015). Sandstone-matrix mélanges, architectural subdivision, and geologic history of accretionary complexes: A sedimentological and structural perspective from the Franciscan Complex of Sonoma and Marin counties, California, USA. &lt;em&gt;Geosphere&lt;/em&gt;, 11(4), pp. 1077–1110. doi: &lt;a href=&quot;https://doi.org/10.1130/GES01137.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1130/GES01137.1&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;E. A. Williams &amp;amp; P. T. Williams (1997). Analysis of products derived from the fast pyrolysis of plastic waste, &lt;em&gt;Journal of Analytical and Applied Pyrolysis&lt;/em&gt;. 40-41, pp. 347-363.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yin, C., Zhao, G., Wei, C., Sun, M., Guo, J., &amp;amp; Zhou, X. (2014). Metamorphism and partial melting of high-pressure pelitic granulites from the Qianlishan Complex: constraints on the tectonic evolution of the Khondalite Belt in the North China Craton. &lt;em&gt;Precambrian Research&lt;/em&gt;, 242, pp. 172-186.&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2018-02-11T13:38:48.673" LastActivityDate="2018-02-11T13:38:48.673" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13334" PostTypeId="2" ParentId="13331" CreationDate="2018-02-09T21:30:48.860" Score="10" Body="&lt;p&gt;I would contend that the fact that the location is a desert has little to nothing to do in most cases to the existence of fossils at the location.  Most of the fossils in the location, at least the ones that make most headlines like major dinosaur deposits, were left there millions of years ago.  The fact that a location today is a desert has no indication of what the climate, or even where on the globe that location was 50 or 100 million years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do not forget about plate tectonics and climate change.  One can go to places like the Judith Basin in Montana, a relatively harsh area of North American Bad Lands, desert or near desert like conditions with cold winters and find fields of fossils from animals that are believed to have lived in tropic marshes of in oceans, because at the time those animals lived, what is now Montana was not inland, and was not at a Northern location.  Millions of years ago it was an undersea plate, thus it has layers of limestone made from ancient single cell sea creatures and sometimes larger objects that were entrapped and preserved as larger fossils.  At other times, those plates rose from the sea floor and homed some of the large creatures, like T-Rex that lived, thrived and sometimes survive as fossils.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Later, that plate move and ended up inland, in what is not North America.   Glaciers, wind, and water may have stripped off many layers of deposits and left exposed or close to exposed the layers of interest to fossil hunters.  Desert regions tend to be subjected to this type of erosion and exposure making such finds easier.  If those same fossils were in and area such as a rich planes area with plentiful plant growth and never subjected to glacial scouring, they could be, and may very well be, right below your feet but under many layers of soil and decaying vegetation, river sediment and other deposits rendering them out of sight and out of reach.&lt;/p&gt;&#xA;" OwnerUserId="6178" LastActivityDate="2018-02-09T21:30:48.860" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13335" PostTypeId="1" CreationDate="2018-02-09T23:48:04.940" Score="3" ViewCount="215" Body="&lt;p&gt;For my class, I was given a hypothetical situation that uses the concept of Maximum Sustainable Yield to see how much fish I should harvest. I am given an initial population, a growth rate, and a carrying capacity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then with these given values, I was supposed to use this information to calculate for next year's population which I easily did with the logistic growth formula. I got a population of 368 (which is obviously rounded to a whole number). From what I know, with this initial population of 368 that I calculated, it would a bit over the one-half capacity but not over the carrying capacity of the environment that was given to me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At this point, I don't know how to apply the Maximum Sustainable Yield concept here. I am not sure on how much I should harvest this year if the current fish population is 368. I don't want to harvest all 368 fish because that would mean that I wiped out the entire population for this year, correct? So would it make sense if I harvested half this number while still have enough fish for next year?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried to look at this graph I found as a reference but I'm not too sure how to apply it: &#xA;&lt;a href=&quot;https://i.stack.imgur.com/Ji5eT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;MSY GRAPH HERE&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I am made a misstep in my process, please do share. Thank you!&lt;/p&gt;&#xA;" OwnerUserId="11305" LastEditorUserId="11305" LastEditDate="2018-02-11T22:05:42.630" LastActivityDate="2018-02-11T22:05:42.630" Title="How to use Maximum Sustainable Yield concept with given a given population, growth rate and carrying capacity?" Tags="|environmental-protection|" AnswerCount="0" CommentCount="7" ClosedDate="2018-02-13T01:25:09.567" ContentLicense="CC BY-SA 3.0" />
  <row Id="13336" PostTypeId="2" ParentId="7888" CreationDate="2018-02-10T13:19:13.273" Score="4" Body="&lt;p&gt;There is no ocean of magma, magma only forms below when rocks have been melted due to various causes like flux melting and heat decompression, the only part of the earth that is liquid is the outer core and it is of uniform composition.&lt;/p&gt;&#xA;" OwnerUserId="12192" LastEditorUserId="2470" LastEditDate="2018-02-11T02:21:33.527" LastActivityDate="2018-02-11T02:21:33.527" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13337" PostTypeId="2" ParentId="13331" CreationDate="2018-02-10T14:17:14.590" Score="15" Body="&lt;p&gt;&lt;strong&gt;Because you find fossils by looking at exposed bedrock, deserts by their nature often have huge expanses of exposed bedrock. The lack of plants is also a big benefit, plant roots tend to destroy fossils&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fossils are everywhere you have sedimentary rock* deserts are actually rather poor at forming fossils compared to many other environments. They are &lt;em&gt;FOUND&lt;/em&gt; more often in deserts because there are no plants or soil covering them up and no plant roots to rip them apart for minerals. You do not need deserts just exposed bedrock. Keep in mind what are deserts now, were rarely deserts when the fossils were buried, your own examples of localities were estuaries, floodplains, and shallow seas respectively and are places far more likely to form fossils.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fossils in other climates are commonly found during road cuts, mining, or large building projects, situations where all the soil is removed exposing bedrock, which of course makes searching the bedrock possible. In many deserts the bedrock is already exposed meaning all you have to do is wander around until you find a fossil poking out. It is far easier to just wander around a patch of desert and search with your eyes then dig up random portions of a forest hoping to find fossils. searching for fossils is almost always visual, which means you need to be able to see the ground and not plants covering the ground. Although in deserts you can use plants, if you see a wide expanse of open desert soil and a single plant, unless there is a water source that plants roots are often wrapped around a fossil, the added minerals from the fossil helping the plant grow better than those around it, plant roots are very destructive and tend to seek out fossils. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The best environments for forming fossils are often wet, floodplains, estuaries, and lakes are great for forming fossils because they have a lot of deposition and the first step in fossilization is burial. Deserts which often have little sedimentation are pretty bad at forming fossils, but they make searching for them so much easier. Quite frankly there are not many paleontologists and they are human, so they tend to hit areas with high chances of finding things.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;there is one other factor, people often don't like paleontologists digging up their property or slowing down construction, but people or governments that own stretches of desert often don't care if you dig up portions of it. So in the desert lucky finds will get expanded exposing more and more of the right layer, while in other environments this would not be economically or legally feasible. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;examples of famous non-deserts, Solnhofen Germany a giant limestone mine, La Brea tar pits, heck the first complete fossils skeleton ever found was found in New Jersey in a coal mine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;**Not every sedimentary layer has fossils, there is a geochemical and physical factor, but a surprisingly large number do.* &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2018-02-15T00:49:50.063" LastActivityDate="2018-02-15T00:49:50.063" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13338" PostTypeId="2" ParentId="13331" CreationDate="2018-02-10T19:05:33.147" Score="4" Body="&lt;p&gt;Because there is nothing in the way. Looking for stuff in a jungle is difficult because of limitation of vision and difficulty of moving equipment and supplies. &#xA; Looking for fossils in downtown Duckburg is difficult because local ordnance prohibits digging big holes.  Deserts, while hostile, are easier to traverse and cater.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many fossils in the UK are found at the beach where the sea and weather erode the land to expose the treasure, and in mines where people are free to dig to their hearts content.&lt;/p&gt;&#xA;" OwnerUserId="12193" LastEditorUserId="106" LastEditDate="2018-02-10T19:20:58.747" LastActivityDate="2018-02-10T19:20:58.747" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13339" PostTypeId="1" CreationDate="2018-02-10T19:28:47.650" Score="4" ViewCount="84" Body="&lt;p&gt;Is there some evidence for this based on gravity anomalies?  I think I know how to tell if a mountain or structure is compensated based on bougeur and free air anomalies, but this really has me stumped?  Does this somehow tie into how underwater mountains are compensated by pratt rather than airy?  &lt;/p&gt;&#xA;" OwnerUserId="12153" LastEditorUserId="725" LastEditDate="2018-02-11T10:16:09.453" LastActivityDate="2018-02-11T10:16:09.453" Title="What gravitational evidence do we have to counter the idea that oceans are formed when continents sink?" Tags="|geology|geophysics|isostasy|geodesy|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13341" PostTypeId="1" CreationDate="2018-02-11T08:04:24.497" Score="6" ViewCount="1907" Body="&lt;p&gt;&lt;a href=&quot;http://www.popsci.com/researchers-find-just-how-much-plastic-were-putting-ocean&quot; rel=&quot;noreferrer&quot;&gt;This article&lt;/a&gt; says that 5 to 13 million metric tons of plastic go into the ocean every year.  In the study &lt;a href=&quot;http://www.teammarine.org/wp-content/uploads/2012/03/Plastic-Buoyancy-Research_Press-Release_TM-09-101.pdf&quot; rel=&quot;noreferrer&quot;&gt;At what point do floating plastics sink?&lt;/a&gt;, they give an estimate of the weight needed to sink plastics.  They reference the paper &lt;a href=&quot;http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.460.4340&amp;amp;rep=rep1&amp;amp;type=pdf&quot; rel=&quot;noreferrer&quot;&gt;Assessing marine debris in deep seafloor habitats off California&lt;/a&gt;, which assesses the amount of plastic debris that has settled to the bottom of the ocean off the coast of California.  Given this information as a starting point... How much plastic settles to the bottom of the oceans each year?&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2019-07-23T21:06:16.063" Title="How much plastic settles to the bottom of the oceans each year?" Tags="|ocean|plastic|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13344" PostTypeId="2" ParentId="13070" CreationDate="2018-02-12T01:30:39.587" Score="2" Body="&lt;p&gt;The reason why there was no large tsunami is due to the reason above, no significant uplift of the sea floor. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, a small tsunami was produced. This was due to vertical features such as trenches and seamounts (basically, undulating bathymetry) moving laterally, in a strike-slip earthquake acting as paddles within the overlying water column. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HGsMm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HGsMm.jpg&quot; alt=&quot;Graphic from Trinidad and Tobago Weather Center&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They have a pretty good overview of the situation here: &lt;a href=&quot;https://www.facebook.com/notes/trinidad-and-tobago-weather-center/the-m76-great-swan-island-earthquake-tsunami/1693553420664701/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The M7.6 Great Swan Island Earthquake &amp;amp; Tsunami&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12198" LastActivityDate="2018-02-12T01:30:39.587" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13345" PostTypeId="1" AcceptedAnswerId="13349" CreationDate="2018-02-12T03:41:28.353" Score="4" ViewCount="191" Body="&lt;p&gt;Ten years ago I studied the third report of the Intergovernmental Panel on Climate Change with some friends. I remember a bit of a hedge in the report, to the effect that general circulation models were not currently modeling climate oscillations (El Niño, the Pacific Decadal Oscillation, etc.), but were beginning to do so. It made me suspicious at the time, that the GCMs were not really capturing the variance we see in the climate. I am curious whether current general circulation models produce these oscillations.&lt;/p&gt;&#xA;" OwnerUserId="10750" LastEditorUserId="10750" LastEditDate="2018-02-13T09:49:14.193" LastActivityDate="2018-02-13T09:49:14.193" Title="Do current general circulation models model climate oscillations?" Tags="|climate-change|climate-models|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13346" PostTypeId="2" ParentId="13345" CreationDate="2018-02-12T11:36:48.917" Score="3" Body="&lt;p&gt;Currently the climate models do model climate oscillations. For example the the fifth assessment report (AR5) of the Intergovernmental Panel on Climate Change (IPCC) summary on the changes of El Niño based on climate model runs says (&lt;a href=&quot;https://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter14_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;AR5, Section 14.4&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;There is high confidence that ENSO will remain the dominant mode of interannual variability with global influences in the 21st century, and due to changes in moisture availability ENSO-induced rainfall variability on regional scales will intensify. There is medium confidence that ENSO-induced teleconnection patterns will shift eastward over the North Pacific and North America. There is low confidence in changes in the intensity and spatial pattern of El Niño in a warmer climate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6465" LastActivityDate="2018-02-12T11:36:48.917" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13347" PostTypeId="1" CreationDate="2018-02-12T13:40:33.087" Score="3" ViewCount="918" Body="&lt;p&gt;From what I understand (please correct me if I'm wrong), the Earth rotates counterclockwise as viewed from the north pole. That means from the perspective of the equator to the north pole, it is rotating clockwise. Hence, if I shoot a projectile towards the north pole from the equator, it should move leftwards likewise if I throw a ball towards the person in front of me in a clockwise-rotating turntable. But, in my textbook and Wikipedia it says that it would go rightwards. Where did I get it wrong?&lt;/p&gt;&#xA;" OwnerUserId="12202" LastEditorUserId="11908" LastEditDate="2018-02-12T18:28:23.227" LastActivityDate="2018-02-15T14:30:52.780" Title="Coriolis effect discrepancy. How to deduce the direction of the effect?" Tags="|coriolis|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13348" PostTypeId="2" ParentId="13341" CreationDate="2018-02-12T14:26:31.717" Score="3" Body="&lt;h1&gt;About 18.2 million tons sink to the ocean floor.&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Every year, an astonishing 260 million tons of plastic waste is produced, and about 10% of it ends up in the ocean. Over time, roughly 70% of the plastic that ends up in the ocean sinks to the ocean floor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore 18.2 million tons of plastic waste end up on the ocean floor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I used &lt;a href=&quot;http://plastic-pollution.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; for my numbers.&lt;/p&gt;&#xA;" OwnerUserId="12057" LastEditorUserId="2570" LastEditDate="2018-02-12T15:06:37.870" LastActivityDate="2018-02-12T15:06:37.870" CommentCount="13" ContentLicense="CC BY-SA 3.0" />
  <row Id="13349" PostTypeId="2" ParentId="13345" CreationDate="2018-02-12T15:10:00.070" Score="6" Body="&lt;p&gt;How the models do at this sort of interannual variability for the current climate is described in Section 9.5 of the Fifth Assessment Report (AR5). For example, the section about ENSO says,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The representation of ENSO in climate models has steadily improved and&#xA;  now bears considerable similarity to observed ENSO properties.&#xA;  However, as was the case in the AR4, simulations of both background climate (time mean and seasonal cycle, see Section 9.4.2.5.1) and internal variability exhibit serious systematic errors, many of which can be traced to the representation of deep convection, trade wind strength and cloud feedbacks, with little improvement from CMIP3 to CMIP5.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;While a number of CMIP3 models do not exhibit an ENSO variability maximum at the observed 2- to 7- year time scale, most CMIP5 models do have a maximum near the observed range and fewer models have the tendency for biennial oscillations. In CMIP3 the amplitude of El Niño ranged from less than half to more than double the observed amplitude. By contrast, the CMIP5 models show less inter-model spread (Figure 9.36). The CMIP5 models still exhibit errors in ENSO amplitude, period, irregularity, skewness, spatial patterns or teleconnections.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;...&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Detailed quantitative evaluation of ENSO performance is hampered by the short observational record of key processes and the complexity and diversity of the processes involved. While shortcomings remain, the CMIP5 model ensemble shows some improvement compared to CMIP3, but there has been no major breakthrough and the multi-model improvement is mostly due to a reduced number of poor-performing models.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In short, it's a bit of a mixed bag and it will depend on which metrics you use to assess the variability.  Something like the NINO3.4 index is simple to calculate, but getting a good (or bad) score doesn't necessarily indicate how well your model simulates the relevant processes (e.g., ocean mixed layer dynamics, air-sea interactions, convection).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Section 9.5 also has information on other modes of variability, including the Pacific Decadal Oscillation, the Madden-Julian Oscillation, Atlantic Meridional Overturning Circulation, etc.  It's worth a read.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2018-02-12T15:10:00.070" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13350" PostTypeId="1" AcceptedAnswerId="13354" CreationDate="2018-02-12T17:01:59.290" Score="3" ViewCount="112" Body="&lt;p&gt;I have recently been learning and researching about meteorite types and classification. Pallasites are mainly composed of a 'solid-solution' of olivine crystals and an iron-nickel alloy. My question is: what is the phase of the iron-nickel alloy, in a body-centered cubic crystal structure (alpha-iron, and hexahedrites) or face-centered cubic?&lt;/p&gt;&#xA;" OwnerUserId="12206" LastEditorUserId="725" LastEditDate="2018-02-12T23:16:36.460" LastActivityDate="2018-02-13T01:42:01.350" Title="Iron-nickel phase in pallasite meteorites" Tags="|geochemistry|mineralogy|meteorite|crystallography|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13351" PostTypeId="2" ParentId="13347" CreationDate="2018-02-12T17:03:56.617" Score="8" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;That means from the perspective of the equator to the north pole, it is rotating clockwise&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That's the part you got wrong.&#xA;As seen from the Equator (as any other point on the Earth), the North pole is not rotating. The rotation only shows up in an external frame of reference. And is actually using an internal frame of reference (like an observer on the equator) what gives rise to the Coriolis force, that is not a real force but just the inertia seen from a rotating frame of reference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the Equator, the North pole is in a fix position, as well as the celestial north pole, that is fix to the Equatorial horizon due north. But the starts and the Sun moves around it from East to West, which is &lt;strong&gt;COUNTERCLOCKWISE&lt;/strong&gt;. That's is because the observer is moving Eastwards.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Coriolis is easier to understood if you imagine that any point on the Earth's surface (or the atmosphere) north of the Equator, have to complete a smaller circle around the Earth axis every 24 hours. Therefore, those points are moving Eastwards at a slower speed than the ones at the equator. Hence, if you shoot a projectile to the North, it will have an excess Eastwards velocity relative to the ground under it, so it will tend to go Eastwards. Which will apear like it is turning &lt;strong&gt;rightwards&lt;/strong&gt;.&#xA;If the projectile is flying south from the Equator, Eastwards will mean &lt;strong&gt;leftwards&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This schematics from &lt;a href=&quot;http://factspage.blogspot.ca/2014/01/what-is-coriolis-effect.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Facts About All&lt;/a&gt; will help in an example:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/fQmut.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fQmut.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's imagine you are at at the monument &quot;La Mitad del Mundo&quot; right on the Equatorial line on Ecuador. And you shoot a projectile straight North to Raleigh, North Carolina, 3,960 km North of &quot;La Mitad  del Mundo&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's say your canon shoots a frictionless projectile at speed of 1,000 km/h. Then the projectile had a Northwards speed of 1,000 km/h, and an Eastward speed of 1,666 km/h which is the speed the canon at Ecuador have in order to go around the earth center every 24 hours.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, in 3.96 hours, the projectile would have reached the latitude of Raleigh, but in the same amount of time the eastward component of its speed took it 6,600 km to the East. However, the eastward velocity of Raleigh is only 1356 km/h&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is because at latitude 35.7° the distance to the Earth rotation axis is only 5,179 km (in contrast with 6,378 km at the equator), therefore, the distance it have to travel around it every 24 hours is only 32,540 km (in contrast to 40,000) requiring a speed of just 1356 km/h.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That means that, while the projectile wast traveling, Raleigh only moved 5,369 km eastwards, 1,231 km less than the projectile, with the consequence that the projectile ended up, 1,231 km to the East of Raleigh (The right as seen from &quot;La Mitad del Mundo&quot;), catastrophically missing the target, and falling in the Atlantic ocean somewhere north of Bermuda.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This excess eastward velocity visualization of Coriolis, seemingly falls apart when considering a projectile shoot due East or West. But it would still be deflected to the right (in the northern hemisphere). An explanation in such case can be found in &lt;a href=&quot;https://physics.stackexchange.com/questions/43124/is-there-an-intuitive-explanation-for-the-southward-force-caused-by-the-coriolis/52509#52509?newreg=d1833cf8d2ea4bbd80eb306f36b85bd9&quot;&gt;this&lt;/a&gt; answer, however that answer is not as clear as I would like, as it just ignores the vertical effect, also known as &lt;a href=&quot;https://en.wikipedia.org/wiki/E%C3%B6tv%C3%B6s_effect&quot; rel=&quot;nofollow noreferrer&quot;&gt;Eötvös effect&lt;/a&gt;, which is important to make sense of the deflection of a projectile traveling East/West. In short, the increased/decreased velocity of a projectile moving East/West, increase/decrease the centrifugal force, so it moves away/towards from Earth's axis of rotation. This means &quot;moves up&quot; at the equator, and move south/north and up (in different proportions) north of the equator. The rightwards deflection is considered part of the Coriolis effect, while the upwards deflection is the Eötvös effect.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-02-15T14:30:52.780" LastActivityDate="2018-02-15T14:30:52.780" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13352" PostTypeId="2" ParentId="13285" CreationDate="2018-02-12T17:23:30.027" Score="4" Body="&lt;p&gt;I'll answer my own question.&#xA;If there is hydrostatic equilibrium, then we have &lt;a href=&quot;https://i.stack.imgur.com/AujXp.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AujXp.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, assuming that the surface pressure is p (in this case 1000hPa) and that the atmosphere's top has zero (0) pressure and infinite height, then &lt;a href=&quot;https://i.stack.imgur.com/YZalw.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YZalw.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this case: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6qRO9.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6qRO9.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, as the atmospheric mass above a surface area is rho times integral of &quot;dz&quot;, and assuming that this area is 1 m^2 to simplify (dx.dy=1):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/swXFR.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/swXFR.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qqrUy.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qqrUy.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; Pa&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we want half of that mass M, then&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YWMhl.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YWMhl.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gkC8W.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gkC8W.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; Pa , which is indeed 500 hPa.&lt;/p&gt;&#xA;" OwnerUserId="6220" LastEditorUserId="6220" LastEditDate="2018-02-14T10:02:27.470" LastActivityDate="2018-02-14T10:02:27.470" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13353" PostTypeId="2" ParentId="13347" CreationDate="2018-02-12T21:19:32.820" Score="2" Body="&lt;p&gt;It's been a while since I've thought about this... and every time it still does take some careful thinking through it all.  But hopefully this can really help you get it put together!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First: Yes the Earth rotates counterclockwise around the Pole...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/N9Kxsm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/N9Kxsm.jpg&quot; alt=&quot;NH rotation&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The thing is, when you shoot an object &quot;due north&quot; towards the North Pole...   &lt;strong&gt;you really aren't shooting it with a due northward velocity&lt;/strong&gt;!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The initial motion of the rocket isn't just it's fired trajectory... but also includes the motion the location it's launching from has.  This is much like if you were in your car driving forward down the interstate, and chose to toss something out the window &quot;directly sideways&quot;... you'd find the can actually continued to move forward as it bounced along the road.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And the thing is, the further poleward a place is, the less eastward velocity those places are rotating with.  Yet your projectile has brought its higher eastward velocity it started with.  So it winds up ahead of where you think it should if going true north, because it rotates eastward faster than that location.  [For the car-can analogy, if someone was driving slower in the lane beside you... the thrown can would actually seem to travel forward away from him, until air resistance worked enough to slow it down......]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Likewise, hopefully you can also see that &quot;eastward&quot; itself is actually changing the direction it points on the overhead view [originally east of Algeria is straight to the right, but by the time it has moved to the end of the green arrow, it becomes up and right].  However the projectile keeps its exact same direction arrow.  If you follow along the path of that arrow, in terms of cardinal directions... its &quot;northward&quot; progression slows, and it actually eventually starts moving what is then south .  So the rotation of the Earth not only alters what we perceive to be east-west movement [turning it to the right in the NH], but also likewise alters the north-south movement [the same turning to the right in the NH occurs, regardless of whether].  We see the rocket as behaving oddly, but the issue isn't with the rocket, but due to the fact that we're actually continually moving AND changing direction to rotate around the Earth.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1ThFB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1ThFB.jpg&quot; alt=&quot;True motion and path&quot;&gt;&lt;/a&gt;&#xA;(Note the Earth rotates too of course, so Algeria will truly have moved around near the area where the yellow arrow ends by the time it gets up there.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;And it may well help a lot to note: &lt;a href=&quot;https://youtu.be/dt_XJp77-mk?t=38&quot; rel=&quot;nofollow noreferrer&quot;&gt;it actually does the exact same (turn right) when operating from a counter-clockwise rotating turntable&lt;/a&gt; too!&lt;/strong&gt; &lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-02-13T10:34:40.080" LastActivityDate="2018-02-13T10:34:40.080" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13354" PostTypeId="2" ParentId="13350" CreationDate="2018-02-12T23:16:20.267" Score="2" Body="&lt;p&gt;First, a correction. A &lt;a href=&quot;https://en.wikipedia.org/wiki/Solid_solution&quot; rel=&quot;nofollow noreferrer&quot;&gt;solid solution&lt;/a&gt; is between different compositions in the same phase. For example, olivine is a solid solution of forsterite (Mg&lt;sub&gt;2&lt;/sub&gt;SiO&lt;sub&gt;4&lt;/sub&gt;) and fayalite (Fe&lt;sub&gt;2&lt;/sub&gt;SiO&lt;sub&gt;4&lt;/sub&gt;).&lt;/p&gt;&#xA;&lt;p&gt;There are two common iron–nickel alloys found in meteorites (pallasites and others): kamacite and taenite. They are commonly intergrown into lamallae called &amp;quot;Widmanstätten pattern&amp;quot;. It looks like this:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BEQIm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BEQIm.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Kamacite has up to about 10% nickel, whereas taenite can get up to ~60% nickel, but commonly found up to 30%.&lt;/p&gt;&#xA;&lt;p&gt;Kamacite has the space group Im3m, making it hexoctahedral body-centered. Taenite has the space group Fm3m, making it hexoctahedral face-centered.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-02-12T23:16:20.267" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13355" PostTypeId="2" ParentId="13350" CreationDate="2018-02-13T01:42:01.350" Score="-1" Body="&lt;p&gt;The metallic part ( essentially all two elements= Iron + nickel) is two phases mixed together : Body Centered Cubic - magnetic, and Face Centered Cubic - nonmagnetic. So the answer to your question is that it is both .  Iron ( BCC) starts to form FCC when Ni exceeds 6 %. The proverbial 18 - 8 stainless steel is 8 % Ni and generally non magnetic austenite phase. My educated guess is the classic  Widmidststten pattern is ferrite ( BCC ) grains/crystals forming from the original austenite ( FCC ) grains/crystals. But it is not that simple as when hot ( 1500 F ) it is 100 % austenite ( FCC ). Further complication is the austenite ( FCC , nickel rich) makes crystal twins . The twins can also give the Widmanstratten structure. And more complicated because temperature history can also affect the FCC / BCC morphology.  [ Maybe I cheated but I searched meteors on the net and learned some but also found some mistakes in the references. ] &lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2018-02-13T01:42:01.350" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13356" PostTypeId="2" ParentId="13285" CreationDate="2018-02-13T02:22:09.630" Score="4" Body="&lt;p&gt;Simple?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Only assumption: &#xA;hydrostatic relation&#xA;$dp = -g \rho dz$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Expanding the RHS yields &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$dp = -g \frac{dM}{dV} dz \frac{dA}{dA} = -\frac{g}{dA} dM$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;($dA dz \equiv dV$)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So any $\Delta p = c \cdot \Delta M$, which means that &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;a pressure difference is proportional to a difference in mass&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;($c$ is relatively constant as long as the gravitational acceleration constant, otherwise you'd have to integrate the hydrostatic eqn.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if the total mass is proportional to a $\Delta p$ of x hPa then the pressure level which separates equal parts is 1/2 of that value.&lt;/p&gt;&#xA;" OwnerUserId="3419" LastActivityDate="2018-02-13T02:22:09.630" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13357" PostTypeId="2" ParentId="9246" CreationDate="2018-02-13T07:00:11.123" Score="0" Body="&lt;p&gt;Because the tropical easterly jet is formed as a result of warming over the Tibetan plateau leading to rising motion and finally the Easterly maxima due to corriolis effect&lt;/p&gt;&#xA;" OwnerUserId="12208" LastEditorUserId="2470" LastEditDate="2018-02-13T07:56:34.487" LastActivityDate="2018-02-13T07:56:34.487" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13361" PostTypeId="2" ParentId="7405" CreationDate="2018-02-13T17:05:46.240" Score="10" Body="&lt;p&gt;Your confusion arise from the definition of East and West hemispheres. That's an arbitrary and confusing definition. Because East and West are relative directions. Meaning they depend on the position were they are specified.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;East and West &lt;a href=&quot;https://en.wikipedia.org/wiki/Cardinal_direction&quot; rel=&quot;noreferrer&quot;&gt;come from the proto-germanic languages&lt;/a&gt;, where East means dawn and West means evening. Therefore, East from any given point is roughly the direction at which the sunrise happen. And West is where the sunset happens.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's why the east/west hemispheres definition is confusing, because if you are in the middle of the pacific, the Western hemisphere is towards the East... confusing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So let's forget about East/West hemispheres, and consider the East/West cardinal directions. Where East is 90° to the right of North and West 90° to the left of North. These directions keep the original spirit, on which East points roughly to the sunrise, and West to the sunset.&#xA;Let's also forget about clockwise and counterclockwise, because that depends on where are you looking from. If you are on top of the North pole it will look like Earth is rotating counterclockwise, but from the top of the South pole it will be clockwise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, when we say that Earth rotates to the East, we mean that each point on the surface is moving to the East of that point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following figure taken from &lt;a href=&quot;http://www.pulauubinstories.com/tag/seasons-day-spa/&quot; rel=&quot;noreferrer&quot;&gt;pulauubinstories.com&lt;/a&gt; will help clarifying the point:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/3z2xk.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3z2xk.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the figure is clear that the fact that sunrise happens to the East is because we are moving in that direction. At dawn, as we move Eastwards we enter in the sunlit side of Earth, producing the sunrise. And as we keep moving Eastwards during the day, we enter in the night side of Earth, leaving the sunshine and the sunset to the West.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, as East means &quot;dawn&quot; it follows (basically by definition) that Earth rotates to the East.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-02-13T17:43:01.210" LastActivityDate="2018-02-13T17:43:01.210" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13362" PostTypeId="1" CreationDate="2018-02-13T21:25:16.883" Score="2" ViewCount="112" Body="&lt;p&gt;I am trying to graphically show the radiance emissions of both the Sun and Earth. I am using NASA's radiance calculator then going to graph it on paper.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is what I typed in:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Low wavelength: 0.1μm&lt;/p&gt;&#xA;&#xA;&lt;p&gt;high wavelength: 100.0μm&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plot 1:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Temp: 5778k &amp;lt;- for the sun's avg temp&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Emissivity: 1.00 &amp;lt;- was unsure what this was for&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plot 2:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Temp: 274.03 &amp;lt;- for the Earth's avg temp&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Emissivity:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;x-axis scale: log&lt;/p&gt;&#xA;&#xA;&lt;p&gt;y-axis scale: log&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is what that all looks like:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/1n02v.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1n02v.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as making a plot of the emitted energy of the Sun and the emitted energy of Earth on the same graph does this look correct?&#xA;How might one annotate/label the curves to show where the peak emission occurs?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Should the x or y axis be dialed down they are between 0.1 to 100.0 and then the y-axis sale 0.01 to 10.000&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I appears that the Suns peak emission is between 0.32 - 10.00microns and the Earth is 10.00microns.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="12218" LastActivityDate="2018-03-16T00:17:45.790" Title="Using NASA's radiance calculator to make a graph to find the where the peak radiation emission are?" Tags="|remote-sensing|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13363" PostTypeId="1" CreationDate="2018-02-13T21:37:04.067" Score="7" ViewCount="2307" Body="&lt;p&gt;We've just published our DIY underwater loggers: &lt;a href=&quot;http://www.mdpi.com/1424-8220/18/2/530&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.mdpi.com/1424-8220/18/2/530&lt;/a&gt;&#xA;and the #1 thing we would like to add to the platform is conductivity. The loggers themselves will easily run longer than a year, but unfortunately we can't find any other projects that get much more than a couple of weeks out of traditional contact probes [like the Atlas series] before they drift quite badly. Does anyone know of other projects building conductivity probes which hold calibration for months to a year? &lt;/p&gt;&#xA;" OwnerUserId="12219" LastEditorUserId="11908" LastEditDate="2018-03-06T00:08:02.983" LastActivityDate="2018-03-06T00:08:02.983" Title="Are there any DIY conductivity sensors that will hold calibration for long periods? {multiple months}" Tags="|hydrology|instrumentation|diy|environmental-sensors|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13364" PostTypeId="2" ParentId="13362" CreationDate="2018-02-13T22:09:03.033" Score="1" Body="&lt;p&gt;The graph looks correct, and after having a look at the &lt;a href=&quot;https://astrogeology.usgs.gov/tools/thermal-radiance-calculator/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA/USGS Radiance calculator&lt;/a&gt;, it seem that curves can't be annotated. However, below the plot there is a button to download the source data of the plot as a comma separated file (CSV), that you can open in Excel or any spreadsheet manager program and plot it with annotations and all the customization you want.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the wavelength of the peak in emission you don't have to look further than the box below the graph titled &quot;Wavelength of Maximum Radiance&quot;, which for the Sun should say something like 0.52 micrometers as in the screenshot below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VSd21.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VSd21.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-02-13T22:22:33.833" LastActivityDate="2018-02-13T22:22:33.833" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13366" PostTypeId="1" AcceptedAnswerId="13370" CreationDate="2018-02-14T13:01:10.257" Score="12" ViewCount="605" Body="&lt;p&gt;If water on Earth came from meteorites, why doesn't Mars have substantial water? What made it more highly probable on Earth than on Mars?&lt;/p&gt;&#xA;" OwnerUserId="12045" LastEditorUserId="94" LastEditDate="2018-02-14T21:01:54.377" LastActivityDate="2021-01-19T20:23:54.540" Title="Water on Mars and Earth" Tags="|meteorology|earth-history|water|meteorite|mars|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13368" PostTypeId="1" CreationDate="2018-02-14T18:28:49.073" Score="3" ViewCount="96" Body="&lt;p&gt;We are studying the water balance of a small catchment close to Jaipur, Rajasthan India in a semiarid climate. About a quarter of the landuse within the catchment is agriculture, the rest is divided among shrub forest, wasteland, fallow land and village areas with mostly unsealed roads. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A crucial part is to estimate the groundwater recharge of these non agricultural landuse classes. From reports we know that the overall recharge should me around 70-100mm/year at an annual precipitation of 611mm. There is no surface runoff in the catchment. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the agricultural crops, the evapotranspiration under standard conditions is calculated via the reference evapotranspiration (fao56 penman-monteith) and a crop-, climate- and growth-specific crop coefficient $K_c$. $ET_{ref}$ is estimated at $\approx 1800$mm/y. The MABIA model that is based on the FAO56 method implemented in WEAP is used for this. MABIA can simulated one non-agricultural landuse class, fallowland. In conjunction with the soil type silty clay, a recharge of 74mm/year is estimated, a value that seems reasonable considering the literature estimates,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the non-agricultural landuse classes, a simple soil moisture model should be employed, where actual evapotranspiration is often described as a function of the current soil moisture. Some studies have transferred the $K_c$ approach to non-agricultural landuse classes such as urban or forest. However, the origins of the actual values were a bit mysterious. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apparently there is a linear relationship between the $NDVI$ and the $K_c$ value, which would make it possible to derive landuse-specific timeseries of the $K_c$ values. However, the $K_c$ refers to the &quot;crop&quot; water requirements under standard conditions. In reality, most of the &quot;natural&quot; vegetation should be under water stress, and derivation of the $K_c$ curves would only be possible for a few years since the land use change is quite fast and would soon lose its validity going back in time. This means that the $K_c$ then should reflect the growth conditions due to precipitation and weather conditions of that particular year and as such should be more related to the actual evapotranspiration than the potential evapotranspiration. This should distort things when estimating the actual evapotranspiration as $$ET_a = ET_{ref} \times K_c \times f(z) $$&#xA;where $f(z)$ is a function that reduces the potential evapotranspiration according to the soil moisture, such as described &lt;a href=&quot;http://www.weap21.org/WebHelp/Two-bucket_Method.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The $K_c$ values obtained for fallow land with this method are considerably below the simulated values from the MABIA method, which results in an $ET$ that is too low, leaving too much water in the system and hence producing too much recharge (around 200mm for fallow).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question now is: Is this $K_c$ approach transferable at all to non-agricultural landuse classes, if so, how can I obtain these values and how would it be used with a soil moisture model and if not, what other ways are there to get a rough estimate of the potential evapotranspiration in these classes?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am aware that this will yield very rough approximations at the very best, but it is a starting point.&lt;/p&gt;&#xA;" OwnerUserId="11466" LastActivityDate="2018-02-14T18:28:49.073" Title="Approaches for estimating potential evapotranspiration for non agricultural landuse classes" Tags="|hydrology|groundwater|gis|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13369" PostTypeId="2" ParentId="13366" CreationDate="2018-02-14T20:47:25.880" Score="5" Body="&lt;p&gt;Mars did have a significant amount of water (and atmosphere) early in its history.  According to NASA, there was enough to form an ocean covering about half its surface: &lt;a href=&quot;https://www.nasa.gov/press/2015/march/nasa-research-suggests-mars-once-had-more-water-than-earth-s-arctic-ocean/&quot; rel=&quot;noreferrer&quot;&gt;https://www.nasa.gov/press/2015/march/nasa-research-suggests-mars-once-had-more-water-than-earth-s-arctic-ocean/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason it doesn't have a lot of water or atmosphere today is that much of it evaporated, essentially because of Mars' smaller size and lower gravity.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2018-02-14T20:47:25.880" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13370" PostTypeId="2" ParentId="13366" CreationDate="2018-02-14T21:18:15.723" Score="13" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;If water on Earth came from meteorites, why doesn't Mars have substantial water?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;First off, that's a conjecture regarding the origin of the Earth's water rather than a known fact. A few times a year or so, a new journal article will appear that argues that the Earth's water is primordial, then another arguing that it came from comets, then yet another arguing that it came from asteroids.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the Earth's water is mostly primordial, most of it is over 4.5 billion years old. If it came from asteroids or comets that collided with the Earth after the Earth had formed, it's still very, very old. Regardless of the source, almost all of the Earth's water has been here for at least 3.8 billion years old, since the end of the late heavy bombardment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same would apply to Mars. It has had almost four billion years to lose its water. So has the Earth; some argue that the Earth, too, has lost a lot of water to space in those four billion years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The key causes of the disparity is that the Earth is significantly more massive and has a magnetic field. Mars's essentially non-existent magnetic field means that water molecules in the atmosphere are more readily split into hydrogen and oxygen than are water molecules in the Earth's atmosphere. Mars's smaller gravitational field means the hydrogen produced by these events has a much greater chance of escaping before it re-forms water than on the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A very recent conjecture poses another possibility, which is that Mar's mantle is slightly different in composition than the Earth's, and this different composition enabled Mars's mantle rocks to absorb significantly more water than did the Earth's.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-02-14T21:18:15.723" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13371" PostTypeId="2" ParentId="13363" CreationDate="2018-02-14T21:47:24.507" Score="9" Body="&lt;p&gt;I've built DIY conductivity probes for subglacial measurements. Unfortunately my sensors remain under ~100m of ice so I haven't be able to recover them to check the calibration, but for the same reason, I've taken multiple measurements to reduce calibration drift, as I'm unable to re-calibrate them. So far, they have produced sensible data for 2+ years, but I haven't check the calibration. However I can share the results of my tests and research in order to produce a stable sensor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are &lt;a href=&quot;https://en.wikipedia.org/wiki/Electrical_conductivity_meter&quot; rel=&quot;noreferrer&quot;&gt;two main types of conductivity measurements&lt;/a&gt;: The first one is the potentiometric method. This is the most common one, and measures conductivity by creating an electric current between two or more electrodes embedded in the medium to measure. The second type is the inductive method, in which is a magnetic field what goes trough the medium, and you measure conductivity through variations in the induction effect that that magnetic field have in a coil.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Dvtpi.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Dvtpi.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(picture  taken from &lt;a href=&quot;http://www.knightequip.com/ump.html&quot; rel=&quot;noreferrer&quot;&gt;Knight&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Inductive probes are contactless, therefore, the most stable ones. However, they are more complex to build and don't work well with very low conductivity (&amp;lt; 100 uS/cm). Glacier water is often in that very low conductivity range, something that, in addition to the higher complexity made me choose the potentiometric method (you can see a bit of my attempts to put together an induction sensor in &lt;a href=&quot;https://forums.adafruit.com/viewtopic.php?f=19&amp;amp;t=54274&quot; rel=&quot;noreferrer&quot;&gt;this forum&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For potentiometric probes, oxidation, deposition of salts or others chemicals can change the calibration parameters. This would be enhanced when direct current is used, as that will create acids in the water that will quickly corrode the probe. To reduce that problem, probes of inert materials are used, like platinum, gold or graphite (more common in DIY projects due to its lower cost). But to reduce deposition of chemical compounds in the probes you still need to avoid direct currents and use high-frequency alternating currents with zero mean, otherwise if there is a net current towards one electrode, you will accumulate acids or ions there that can degrade or coat the electrode and change its properties (i.e. change the calibration).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RUhl3.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RUhl3.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The picture above shows an example of an electric signal that can be generated using a false ground and the PWM output of an Arduino board. The setup could be as follows:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/m2rBl.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/m2rBl.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where R1 and R2 have in general to be equal to ensure a signal with zero mean, and the value have to be chosen depending of the range of conductivity values you want to measure and the resolution. If you want to cover  a wide range (pure cave water to marine water), you will have very low resolution (un less you use a AD converter with more resolution than the 10-bits provided by Arduino boards). Alternatively you can have multiple sensors each one optimized for a different range.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For probes meant to be deployed outside of lab conditions, concentric electrodes are recommended, otherwise natural currents going trough the ground/water can affect the measurements. The setup I used is this one:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/6MHBQ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6MHBQ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;Where a central graphite electrode is surrounded by a ring of graphite electrodes. As  you can't solder to graphite, I used conductive epoxy to glue it to a piece of plumbing copper tube modified with legs so it can be solder to a PCB. It looks like this:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/d6zrU.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/d6zrU.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To avoid gluing, some people choose aluminium or stainless steel electrodes, that are affordable and do not suffer much of chemical corrosion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some of the data that was produced by this probes were used for &lt;a href=&quot;https://www.the-cryosphere-discuss.net/tc-2017-270/&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt; publication.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many comercial setups use three or four electrodes. I don't understand all the advantages of those sensors. In some cases they are just multiple sensors each one calibrated  for a specific range.&#xA;I've also seen three concentric electrodes. I haven't do the math, but my suspicion is that they measure the current in two independent electrodes with different surface area. Then, you can model and calculate the resistivity of the layer of deposits/corrosion that covers the electrodes and compensate your reading accordingly, reducing the calibration drift issues.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-02-15T18:49:48.737" LastActivityDate="2018-02-15T18:49:48.737" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13373" PostTypeId="1" CreationDate="2018-02-15T02:50:15.617" Score="4" ViewCount="233" Body="&lt;p&gt;I have an EDGAR emissions data-set. I would like to speciate the VOC emissions for CBMZ mechanism. Could anybody help? thanks&lt;/p&gt;&#xA;" OwnerUserId="6489" LastEditorUserId="6489" LastEditDate="2020-10-15T03:35:40.617" LastActivityDate="2020-10-15T03:35:40.617" Title="How to speciate EDGAR emissions for CBMZ?" Tags="|air-quality|emissions|r|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13374" PostTypeId="1" CreationDate="2018-02-15T07:10:11.307" Score="2" ViewCount="94" Body="&lt;p&gt;I am looking for the geomagnetic data for the Indian Ocean region. The 3D data should correspond to longitude-latitude grids at hourly intervals.&#xA;The model data is easily available at NOAA but I need the observed values (satellite as well as surface observations) for the year 2017. I also checked the NOAA and USGS website but none of them are providing their data for the specific spatial domain.&lt;/p&gt;&#xA;" OwnerUserId="11162" LastEditorUserId="94" LastEditDate="2018-02-15T12:29:30.170" LastActivityDate="2018-02-15T13:09:04.990" Title="Where can I find geomagnetic observations for the Indian Ocean region in 2017?" Tags="|open-data|geomagnetism|satellites|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13375" PostTypeId="2" ParentId="13374" CreationDate="2018-02-15T10:37:22.100" Score="1" Body="&lt;p&gt;For surface data, a good place to start is &lt;a href=&quot;http://www.intermagnet.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Intermagnet&lt;/a&gt;, a global network of geomagnetic observatories. Their &lt;a href=&quot;http://www.intermagnet.org/data-donnee/download-eng.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;data download page&lt;/a&gt; lets you filter by time span and region, and sample rates down to the second are available for some observatories. The data are direct observations from individual observatories at fixed locations, and are not averaged over a region. (You mention in a comment that you couldn't find a station for ‘the northern equatorial part of the region near India’; for this region I'd suggest &lt;a href=&quot;http://www.intermagnet.org/imos/imos-list/imos-details-eng.php?iaga_code=GAN&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gan in the Maldives&lt;/a&gt;.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For recent satellite data, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Swarm_(spacecraft)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Swarm mission&lt;/a&gt; provides an excellent resource. &lt;a href=&quot;https://earth.esa.int/web/guest/swarm/data-access&quot; rel=&quot;nofollow noreferrer&quot;&gt;This page&lt;/a&gt; gives instructions on how to download their freely available data sets. Registration is required, but as far as I can tell it's free and available to anyone. They've also got an &lt;a href=&quot;https://earth.esa.int/web/guest/missions/esa-operational-eo-missions/swarm/news/-/article/visualisation-tool-for-swarm-data-now-open-for-users&quot; rel=&quot;nofollow noreferrer&quot;&gt;excellent online visualization tool&lt;/a&gt; which lets you explore their data interactively.&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2018-02-15T13:09:04.990" LastActivityDate="2018-02-15T13:09:04.990" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13378" PostTypeId="1" CreationDate="2018-02-15T20:39:22.133" Score="1" ViewCount="27" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xHQgm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xHQgm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Look at the brightest parts of the photo and use a radiance calculator to find the   blackbody radiation curve (show the    plot    of  the curve) and  the wavelength  of  maximum emission.   How do these compare    with    the Earth’s?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could someone please explain how this would be solved?&#xA;The calculator I can use is:&#xA;&lt;a href=&quot;https://astrogeology.usgs.gov/tools/thermal-radiance-calculator/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://astrogeology.usgs.gov/tools/thermal-radiance-calculator/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="12218" LastActivityDate="2018-02-15T20:39:22.133" Title="Looking at the brightest parts of the image how would one find the blackbody curve and wavelength maximum using a radiance calculator?" Tags="|waves|atmospheric-radiation|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13379" PostTypeId="1" AcceptedAnswerId="13380" CreationDate="2018-02-15T21:44:37.453" Score="3" ViewCount="917" Body="&lt;p&gt;The Sun is  estimated   to  have    had a   solar   luminosity  about   30% lower   when    the solar   system  was formed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now if I assumed that Earth's albedo was the same as it is today, what would have been the effective radiating temperature of the Earth at that time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My solution:&#xA;T_e = S/4*(1 - A)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that Earth's current albedo is A = 0.3.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hence,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;T_e = S/4*(1 - 0.3)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;T_e = ( (0.7)*(1370) ) / (4 (5.67*10^-8))  * (1-0.3) = 233K&lt;/p&gt;&#xA;&#xA;&lt;p&gt;233K &amp;lt;- would have been Earth's effective radiating temperature&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now if one assumes the magnitude of the greenhouse effect was the same then (now it is 33k) Earth's temperature would be:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;233K + 33K = 266K&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming the math is right between those two would there have been liquid water on Earth? If there would be, how does one resolve this paradox? that is, given that albedo was the same, what element of the climate system could explain this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="12218" LastEditorUserId="12218" LastEditDate="2018-02-15T21:51:00.610" LastActivityDate="2018-02-22T10:56:40.137" Title="Calculating 30% less solar energy. Provided the math is right, would there have been liquid water on Earth?" Tags="|climate-change|greenhouse-gases|" AnswerCount="1" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13380" PostTypeId="2" ParentId="13379" CreationDate="2018-02-15T22:44:21.650" Score="3" Body="&lt;p&gt;Quick and simple answer: A greater greenhouse effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is an equilibrium in place. CO2 weathering rates depend on temperature, so at lower temperatures, we see CO2 levels rise, warming the planet. At higher temperatures, higher weathering rates mean more CO 2 drawdown, so the planet cools.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a very long term process. But this CO2 thermometer effect is believed to be the reason why we have had liquid oceans for all of known earth history.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as the black body effect goes; this is correct - from the viewpoint of an observer at distance, Earth would 'appear' colder. However, this is because the emission height changes (see &lt;a href=&quot;https://andthentheresphysics.wordpress.com/2014/03/05/effective-emission-height/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://andthentheresphysics.wordpress.com/2014/03/05/effective-emission-height/&lt;/a&gt; ) for more of an explanation. Think of it as 'the height at which the atmosphere becomes IR-opaque' (although this is a simplification); the temperature then follows the lapse rate down to the ground. So raising the emission height raises the surface temperature. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(NB late at night, add refs later..)&lt;/p&gt;&#xA;" OwnerUserId="8217" LastEditorUserId="8217" LastEditDate="2018-02-22T10:56:40.137" LastActivityDate="2018-02-22T10:56:40.137" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13384" PostTypeId="1" CreationDate="2018-02-16T07:15:38.013" Score="1" ViewCount="8493" Body="&lt;p&gt;There's always confusion and disagreement when these terms are mentioned. Need to be sure of their exact meanings. &lt;/p&gt;&#xA;" OwnerUserId="12237" LastEditorUserId="94" LastEditDate="2018-02-16T07:27:15.307" LastActivityDate="2018-02-16T07:27:15.307" Title="What are the differences between alluvial, eluvial and colluvial deposits?" Tags="|geology|sedimentology|terminology|mining|" AnswerCount="1" CommentCount="0" ClosedDate="2018-02-16T16:40:48.490" ContentLicense="CC BY-SA 3.0" />
  <row Id="13385" PostTypeId="2" ParentId="13384" CreationDate="2018-02-16T07:25:11.597" Score="2" Body="&lt;p&gt;Your question is almost a duplicate of &lt;a href=&quot;https://earthscience.stackexchange.com/q/2901/94&quot;&gt;What is the difference between eluvium and alluvium?&lt;/a&gt;, but you also ask about colluvial deposits. The &lt;a href=&quot;https://earthscience.stackexchange.com/a/2903/94&quot;&gt;accepted answer&lt;/a&gt; for that question references &lt;a href=&quot;https://australianmuseum.net.au/geological-ore-deposits&quot; rel=&quot;nofollow noreferrer&quot;&gt;this convenient guide&lt;/a&gt; from the Australian Museum, which also covers colluvial deposits:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Alluvial: Detrital material which is transported by a river and usually deposited along the river's pathway, either in the riverbed itself or on its floodplain.&lt;/p&gt;&#xA;&lt;p&gt;Colluvial: Weathered material transported by gravity action such as on scree slopes.&lt;/p&gt;&#xA;&lt;p&gt;Eluvial: Weathered material still at or near its point of formation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="94" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-02-16T07:25:11.597" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13386" PostTypeId="2" ParentId="13285" CreationDate="2018-02-16T08:42:46.047" Score="4" Body="&lt;p&gt;I always found this style question interesting as a meteorology graduate teaching assistant, as there often seemed to be a variety of ways to attempt to answer it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's also often one of the earlier abstract type of questions in lower-level meteorology courses, and thus one I really encouraged my students to avoid resorting to help with the answer too quickly on, as exercises like these prove vital to developing persistence and creativity in trying to derive meteorological equations - and if you can't learn to fight through questions like these, you'll be lost in dynamics/thermodynamics/etc and beyond...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;So if you're in a course with this type of question assigned, as much as it's painful, if haven't gotten your own good answer yet, please keep retrying and rereading on your own until you come up with something, even if only partial or uncertain. You'll learn more that way than by reading answers in the long run.  And then come back after the assignment is over and learn some more here!&lt;/strong&gt; &#xA;&lt;hr&gt;&#xA;But, call me crazy or handwavy, but I believe you can get there even easier by recalling back to earlier equations:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$${\text{Pressure} \ ≡ \ \frac{\text{Force}}{\text{Area}}}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming we're talking atmospheric pressure, we should be talking only about the the force due to the weight of air above, so&#xA;$${\text{Force}} \ = \ {m_{above}}\cdot g$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And setting up the two levels:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$${\text{Pressure}_{(Level\,=\,Ground)}} \ =&#xA; \ {m_{(Full\,Atmospheric\,Column)}}\cdot g$$&#xA;$${\text{Pressure}_{(Value\,Where\,1/2\,Mass)}} \ = \ 0.5 \cdot m_{(Full\,Atmospheric\,Column)}\cdot g$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll leave the one or two fairly basic high school algebra substitution steps for future readers needing proper completeness, but it quickly becomes the simple:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$${\text{Pressure}_{(Value\,Where\,1/2\,Mass)}} \ = \ 0.5 \cdot {\text{Pressure}_{(Level\,=\,Ground)}}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\text{So} \ 0.5 \cdot 1000 \ {\text{mb}} = \fbox{500 mb} $$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Naively the only place I can really see anyone even trying to take issue is in defining atmospheric pressure as simply the weight of air above it, overlooking things like vertical perturbation pressures.  But of course those are just that, &lt;strong&gt;perturbations&lt;/strong&gt;, and thus not a part of the &lt;strong&gt;mean&lt;/strong&gt; atmospheric pressure.  But perhaps I'm wrong somewhere along the way???&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-02-20T04:55:44.383" LastActivityDate="2018-02-20T04:55:44.383" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13388" PostTypeId="1" CreationDate="2018-02-16T17:33:35.357" Score="1" ViewCount="21" Body="&lt;p&gt;In meteorological terminology within dynamics, there are usually one of two unique assumptions made:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Baroclinic- density is a function of both temperature and pressure : $\rho(x,y,z,t)=\frac{P(x,y,z,t)}{R_dT(x,y,z,t)}$&lt;/li&gt;&#xA;&lt;li&gt;Barotropic- density is a function of only pressure : $\rho(x,y,z,t)=\frac{P(x,y,z,t)}{R_dT_0}$&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;However, these simple, yet often used and powerful definitions miss something important- the effect of water vapor. To get around this, often meteorologists make virtual temperature, that is $$T_v(x,y,z,t)=T(x,y,z,t)[1+\epsilon q(x,y,z,t) ]$$ where $q$ is the mixing ratio and $\epsilon$ is the ratio of the molar mass of water vapor to the molar mass of dry air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Incorporating this into the definition of baroclinic is easy: $\rho(x,y,z,t)=\frac{P(x,y,z,t)}{R_dT_v(x,y,z,t)}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Incorporating this into a barotropic assumption however, is difficult. What would the approach be? I would consider this important conceptually for the tropics, where the barotropic assumption is most often made, but is mostly covered in water.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2018-02-16T17:33:35.357" Title="Is there such a thing as virtual barotropic?" Tags="|meteorology|thermodynamics|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13390" PostTypeId="1" CreationDate="2018-02-16T19:26:51.803" Score="4" ViewCount="67" Body="&lt;p&gt;Does mineral weight contribute to the &lt;a href=&quot;https://web.stanford.edu/group/Urchin/mineral.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;prevalence of minerals&lt;/a&gt; in seawater? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is there five times more copper in seawater than Iron?&#xA;Why is there 4000 times more strontium in seawather than Iron, when strontium is 30% heavier?&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2018-02-21T03:59:21.933" LastActivityDate="2018-02-21T03:59:21.933" Title="Reason for higher content of Iodine and Copper than Iron in Seawater?" Tags="|ocean|geochemistry|water|salinity|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13391" PostTypeId="1" AcceptedAnswerId="13392" CreationDate="2018-02-16T20:29:13.440" Score="17" ViewCount="1881" Body="&lt;p&gt;Suppose that I haven't taken a shower for a while, or haven't disposed of my trash, or something, and the room I've been in now stinks. Then, to remove the smell from the room (presumably after first throwing me out of it), you can just open a window or door, and let in the fresh air. Intuitively, the reason this doesn't leave a permanent stench outside, is because there's a lot more atmosphere outside than inside, thus diluting the smell so much it becomes unnoticeable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But wait! There are billions of people on the planet, and life has existed on the planet for billions of years. And surely, most of the lifeforms that have existed here have made lots of bad smells, perhaps especially after they're dead. (And I sure don't think dogs smell good when they're alive either, for that matter.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And yet, we call the air fresh, for the most part. So I suppose that, over time, the bad smells must have been destroyed or absorbed somewhere, and now I'm curious as to where. Would you have any ideas?&lt;/p&gt;&#xA;" OwnerUserId="12244" LastActivityDate="2018-10-27T21:39:16.153" Title="Where do bad smells eventually go?" Tags="|atmosphere|air-pollution|air|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13392" PostTypeId="2" ParentId="13391" CreationDate="2018-02-16T20:58:55.980" Score="17" Body="&lt;p&gt;If you are smelling something, you are inhaling gases, particles, or a combination of the two.  They don't normally build up in the atmosphere because of three reasons:  transport/dilution (which you mentioned), &lt;strong&gt;chemistry&lt;/strong&gt;, and &lt;strong&gt;deposition&lt;/strong&gt;.  Yes there is plenty of fresh air out there but as you say, over billions of years there would be a lot of accumulation of odorous compounds if it weren't going somewhere.  Though, stinky air does get trapped near the ground sometimes during stagnation events, caused by a temperature inversion close to the surface which prevents mixing with the upper air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Atmospheric chemistry usually involves the hydroxyl radical (OH) in some way.  Rapid chemical conversions of gases often depends on OH, which is cycling and replenished thanks to the abundance of oxygen and water vapor in the atmosphere.  Many gaseous pollutants will go through a series of chemical reactions with OH, other chemicals, and/or sunlight.  They are then converted to simpler chemicals that we don't really smell.  Most odorous pollutants are chemically converted quickly (e.g. hours, days).  Some pollutants do take years to convert (e.g. methane) and so accumulate in the atmosphere.  We don't smell them, though, because our ability to &quot;smell&quot; things is limited to organic compounds and other molecules like hydrogen sulfide and ammonia (see &lt;a href=&quot;https://en.wikipedia.org/wiki/Odor#Physiology_of_smell&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Deposition of air pollutants is dominated by precipitation, whereby rain can scavenge particles and chemically react with gases.  The rain deposits the pollutants (usually in a modified form) onto the surface of the Earth.  Dry deposition also occurs, especially with &quot;sticky&quot; compounds like ammonia.  However, dry deposition is not nearly as efficient as wet deposition.  Though, if particles are large enough, they will settle out of the atmosphere relatively quickly and deposit on the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suggest you read up a little on the topic &lt;a href=&quot;https://en.wikipedia.org/wiki/Air_pollution&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; to get you more familiar with the different factors that affect air pollutants.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2018-10-27T21:39:16.153" LastActivityDate="2018-10-27T21:39:16.153" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="13393" PostTypeId="1" CreationDate="2018-02-18T01:31:15.350" Score="3" ViewCount="101" Body="&lt;p&gt;I'm a keen skier, and I've often been happily surprised by snow fall despite temperatures of 1 or even 2 °C.&#xA;After some research I found that the explanation relies in assuming that these above freezing temperatures are confined to a layer close to the surface as explained here:&#xA;&lt;a href=&quot;https://www.onthesnow.com/news/a/15198/can-it-snow-when-temps-are-above-freezing&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.onthesnow.com/news/a/15198/can-it-snow-when-temps-are-above-freezing&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, today I saw the same phenomenon on a ski resort that reports temperatures at different heights, suggesting that the above freezing temperatures extended by at least a kilometer from the base. However,  there were fluffy snowflakes falling anyways.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can that happen?&lt;/p&gt;&#xA;" OwnerUserId="12251" LastEditorUserId="6370" LastEditDate="2018-02-19T15:42:21.033" LastActivityDate="2018-02-19T15:42:21.033" Title="How can snow be falling with consistent above freezing temperatures?" Tags="|precipitation|snow|" AnswerCount="0" CommentCount="5" ClosedDate="2018-02-20T17:06:56.033" ContentLicense="CC BY-SA 3.0" />
  <row Id="13394" PostTypeId="2" ParentId="13285" CreationDate="2018-02-18T01:31:52.470" Score="3" Body="&lt;p&gt;Pressure in a fluid is, literally, the &lt;strong&gt;weight of the fluid above&lt;/strong&gt; the point of measure, per unit area, so if you have half the amount of air (or water, for the matter) above you, then you will measure exactly half the amount of pressure. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the answer is 500 hPa. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is valid under the standard hydrostatic approach (no turbulence forces; no dynamic forces).&lt;/p&gt;&#xA;" OwnerUserId="1379" LastEditorUserId="1379" LastEditDate="2018-03-14T07:57:09.543" LastActivityDate="2018-03-14T07:57:09.543" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13396" PostTypeId="1" AcceptedAnswerId="13398" CreationDate="2018-02-18T06:32:41.303" Score="6" ViewCount="166" Body="&lt;p&gt;According to ice core samples from Vostok in Antarctica, methane and carbon dioxide levels seem to have risen and fallen at around the same time over a 450 thousand year period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was unable to find any article or explanation on why the levels of individual greenhouse gases in the past seem to coincide. Could someone please offer an explanation for this?&lt;/p&gt;&#xA;" OwnerDisplayName="user12254" LastEditorUserId="2470" LastEditDate="2018-02-18T11:06:23.390" LastActivityDate="2018-02-18T18:42:58.230" Title="In the past, why did the levels of individual greenhouse gases rise and fall at the same time?" Tags="|temperature|greenhouse-gases|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13398" PostTypeId="2" ParentId="13396" CreationDate="2018-02-18T18:42:58.230" Score="4" Body="&lt;p&gt;CO2 and methane both have natural feedback loops that can cause increasing temprature to release more of both, which in turn causes more warming which causes more release and so on and so forth. This is one of the big worries about human caused greenhouse gasses, that they will trigger these feedback loops causing far more drastic warming. Negative feedback loops also exist so making it colder can trap more or release less of these gases. I will give a few examples of those feedback loops. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://geology.com/articles/methane-hydrates/&quot; rel=&quot;noreferrer&quot;&gt;Methane hydrates&lt;/a&gt;, A lot of the seafloor has methane hydrates trapped in the sediment, if you warm that material it releases methane gas, a lot of it. This material builds up very slowly but can be released very quickly, so there is plenty available to warming water to release. Higher pressure can mitigate this but the temprature has a stronger effect than pressure from rising sea levels. Of course if you cool the sea more of this methane is trapped as hydrates reducing the amount in the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Permafrost also contains methane hydrates and other organics, the cold and ice keeps them inactive and trapped but warming it triggers the release of both methane and trapped carbon (which is released as CO2). so as the polar regions warm the release out these stored gasses, if they get colder they trap more it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Biology, there is a really interesting feedback loop in microbial life, ocean and wetland life in particular respond to warmer temperatures by releasing more CO2(or absorbing less), how much is difficult to estimate but that they do increase CO2 has been repeatedly &lt;a href=&quot;http://archive.sciencewatch.com/dr/nhp/2011/11maynhp/11maynhpFran/&quot; rel=&quot;noreferrer&quot;&gt;confirmed&lt;/a&gt; even if weak on a geological time scale this will quickly add up. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This effect is much stronger in wetlands and wetlands have the additional effect of releasing more methane with warming temprature at the same time, &lt;a href=&quot;https://en.wikipedia.org/wiki/Methanogenesis&quot; rel=&quot;noreferrer&quot;&gt;Methanogenesis&lt;/a&gt;. additionally  they also convert CO2 into methane and how much is based on CO2 concentration and temprature, so increasing CO2 will result in more methane directly. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ocean circulation, warming the planet changes ocean circulation patterns, and the current pattern with a lot of mixing due to wide differences in temperature. is really good at absorbing methane and CO2 into sediment and microorganisms. warmer oceans result in less mixing which means less gases released by other means getting absorbed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On a geologic scale the movement of continents can affect all of these, so that adds one more thing that will tend to change both in the same ways.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2018-02-18T18:42:58.230" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13400" PostTypeId="1" CreationDate="2018-02-19T09:15:57.330" Score="4" ViewCount="1874" Body="&lt;p&gt;There's a lot of evidence that:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;mankind is putting a lot of CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere&lt;/li&gt;&#xA;&lt;li&gt;CO&lt;sub&gt;2&lt;/sub&gt; levels are currently rising&lt;/li&gt;&#xA;&lt;li&gt;CO&lt;sub&gt;2&lt;/sub&gt; contributes to the green-house effect, which contributes to increase earth temperature&lt;/li&gt;&#xA;&lt;li&gt;the earth temperature has been increasing in the past decades&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;There's also evidence that:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;CO&lt;sub&gt;2&lt;/sub&gt; levels have been going up and down for as long as we can look at them without human intervention. E.g. &lt;a href=&quot;https://climate.nasa.gov/climate_resources/24/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this NASA graph&lt;/a&gt; spanning 400.000 years&lt;/li&gt;&#xA;&lt;li&gt;global temperature is still inside the bounds of normal cyclical Holocene variations (as seen on &lt;a href=&quot;https://en.wikipedia.org/wiki/Geologic_temperature_record&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;earth temperature has been going up and down for millions of years, obviously without human intervention, as seen on the same Wikipedia page&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The first set of facts I listed proves without a doubt that some of our activity is causing an increase of temperature of some unknown magnitude, but not much more. When confronted with the second set of facts I listed, scientists usually reiterate the first four facts, and add that there's a huge consensus among scientists (97% !) that human activity is the main driver of climate change, which is certainly the case, but is obviously not a proof.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They also say that reducing our CO&lt;sub&gt;2&lt;/sub&gt; emissions won't hurt anyway and that a 2 °C temperature increase would be catastrophic. This is a very good reason to act, but this still doesn't prove anything.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Digging in the research, the main evidence I've seen relies on the fact that our models can't explain the current change in temperature without taking into account human activity. When opposed that those models could be wrong, the usual answer is that we know they work because they explain past changes, but this not a very strong point since those models have been calibrated using past data (in the financial world, this is a well-known issue with models trying to predict stocks changes)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other piece of evidence is that the other factors &lt;em&gt;we know about&lt;/em&gt; (solar activity, volcano activity, changes in earth orbit, deforestation changing the energy reflected by some of the landmass, human-released aerosols reflecting more energy, etc... ) don't seem to be behind the recent increase in temperature. So the increase must be mainly caused by the anthropogenic CO&lt;sub&gt;2&lt;/sub&gt; , for lack of a better explanation. This is a strong point, but isn't a proof per se.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there other, possibly stronger points to support the claim that the CO&lt;sub&gt;2&lt;/sub&gt; human activity is releasing in the atmosphere is the main driver of climate change?&lt;/p&gt;&#xA;" OwnerUserId="12262" LastEditorUserId="725" LastEditDate="2018-03-30T14:37:32.347" LastActivityDate="2022-05-24T14:31:28.030" Title="What evidence is backing the claim that the CO₂ we're releasing in the atmosphere is the main cause of climate change?" Tags="|climate-change|" AnswerCount="5" CommentCount="13" ContentLicense="CC BY-SA 3.0" />
  <row Id="13401" PostTypeId="1" CreationDate="2018-02-19T12:20:48.507" Score="4" ViewCount="57" Body="&lt;p&gt;I'm wondering how good the climate models of the recent past have been at predicting the current climate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Notably, I've heard quite a few times that the temperature was increasing faster than the models projections. Is this the case? &lt;/p&gt;&#xA;" OwnerUserId="12262" LastActivityDate="2018-02-19T12:20:48.507" Title="How well do past climate models stick to current observations?" Tags="|climate-change|climate-models|" AnswerCount="0" CommentCount="7" ClosedDate="2018-02-22T14:50:17.117" ContentLicense="CC BY-SA 3.0" />
  <row Id="13402" PostTypeId="2" ParentId="13400" CreationDate="2018-02-19T12:47:26.040" Score="5" Body="&lt;p&gt;The past models (which all link climate change to CO2) can be evaluated for their ability to predict the current climate.&lt;/p&gt;&#xA;&lt;p&gt;Such a comparison for successive climate models can be found &lt;a href=&quot;https://www.carbonbrief.org/analysis-how-well-have-climate-models-projected-global-warming&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;. Quoting from the conclusion of the report :&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Climate models published since 1973 have generally been quite skillful in projecting future warming. While some were too low and some too high, they all show outcomes reasonably close to what has actually occurred, especially when discrepancies between predicted and actual CO2 concentrations and other climate forcings are taken into account.&lt;/p&gt;&#xA;&lt;p&gt;Models are far from perfect and will continue to be improved over time. They also show a fairly large range of future warming that cannot easily be narrowed using just the changes in climate that we have observed.&lt;/p&gt;&#xA;&lt;p&gt;Nevertheless, the close match between projected and observed warming since 1970 suggests that estimates of future warming may prove similarly accurate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="12262" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-02-19T12:47:26.040" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13405" PostTypeId="2" ParentId="240" CreationDate="2018-02-19T22:26:26.680" Score="3" Body="&lt;p&gt;The earth would be dead without a molten core. There would be no volcanoes, earthquakes etc no plate tectonics. Any material eroded from mountains would eventually end up at the bottom of the sea, and then stay there. Eventually there would be no land above sea level. Erosion would continue until we are left with nothing but deep seas with little or no mineral nutrients. Not great for a rich diversity of life.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So when we hear of the natural disasters of volcanoes and earthquakes, appreciate that the very earth is alive and sustaining us. &lt;/p&gt;&#xA;" OwnerUserId="12266" LastActivityDate="2018-02-19T22:26:26.680" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13416" PostTypeId="1" AcceptedAnswerId="13418" CreationDate="2018-02-22T05:13:27.130" Score="20" ViewCount="6101" Body="&lt;p&gt;I was doing a project for my English class, and I came upon the article &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pubmed/23472299&quot; rel=&quot;nofollow noreferrer&quot;&gt;Energy conservation in the earth's crust and climate change&lt;/a&gt;. I can't view the full text of the article, but the abstract piqued my interest:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do long hydrocarbons in the earth actually have a significant effect in insulating the surface? Also, has the lack of these hydrocarbons resulted in any significant warming of the Earth thus far?&lt;/p&gt;&#xA;" OwnerUserId="785" LastEditorDisplayName="user12525" LastEditDate="2019-04-22T10:28:11.767" LastActivityDate="2021-09-18T16:10:26.950" Title="Do fossil fuels insulate the crust from the Earth's interior?" Tags="|climate-change|geothermal-heat|crust|thermodynamics|fossil-fuel|" AnswerCount="4" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13418" PostTypeId="2" ParentId="13416" CreationDate="2018-02-22T07:57:02.440" Score="34" Body="&lt;p&gt;Quoting from &lt;a href=&quot;http://www.tandfonline.com/doi/full/10.1080/10962247.2013.803404?src=recsys&quot; rel=&quot;noreferrer&quot;&gt;John Russell's response to this article&lt;/a&gt;, &quot;This is arrant nonsense!&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Russell concludes with&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How did this paper get through the peer-review and editorial review processes? What technical standards were applied to determine the apparent merit of its contents so as to justify its inclusion in a reputable journal?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Just because something is published in a scientific journal does not mean it is fact. Publication is where science starts rather than ends. Sometimes, pure garbage manages to slip through peer review and get published, even in reputable journals. This is one of those times. Moreover, the publisher of the underlying journal, Taylor &amp;amp; Francis, has had issues with shoddy peer review.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth's energy imbalance is 0.6±0.17 W/m&lt;sup&gt;2&lt;/sup&gt;. The Earth's internal energy budget, the amount of energy that escapes from the interior of the Earth, is 0.087 W/m&lt;sup&gt;2&lt;/sup&gt;, about half the uncertainty in the Earth's energy imbalance. (That largish uncertainty is because the imbalance is a difficult quantity to measure.) Even if all of that 0.087 W/m&lt;sup&gt;2&lt;/sup&gt; is due to humans removing the Earth's insulating layer of hydrocarbons (it isn't), it does not come close to accounting for the 0.6±0.17 W/m&lt;sup&gt;2&lt;/sup&gt; imbalance. The numbers don't add up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or as John Russell put it in his response to the referenced article, &quot;This is arrant nonsense!&quot;&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-02-22T07:57:02.440" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13419" PostTypeId="2" ParentId="13416" CreationDate="2018-02-22T09:33:56.313" Score="15" Body="&lt;p&gt;What neither the authors nor the response by John Russell takes into account is that all underground oil and gas is stored inside tiny pores of rocks. An oil reservoir is not a big underground cave, it is a very fine-grained sponge made of stone filled with oil. In essentially all cases, there is more stone than oil (by volume).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This means that since oil is a much better insulator than rock, basically all of the thermal energy conducted from bottom to top of an oil reservoir is going through the stone in the first place (when the reservoir is full). Thus the total thermal conductivity of the reservoir does not really change when hydrocarbons are produced, it's still mainly the stone conducting heat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's just one more thing wrong with this arrant nonsense.&lt;/p&gt;&#xA;" OwnerUserId="12279" LastActivityDate="2018-02-22T09:33:56.313" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13420" PostTypeId="2" ParentId="13400" CreationDate="2018-02-22T10:02:08.090" Score="18" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;What evidence is backing the claim that the C02 we're releasing in the&#xA;  atmosphere is the main cause of climate change?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As you said in your comment:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I agree that, if the proof is too complicated to be understood by a&#xA;  layman, your only choice is to rely on scientific consensus&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Complication regarding proof or evidence based consensus in science is tricky.   Should we accept things that we don't understand, that scientists say are so, &lt;a href=&quot;https://ih1.redbubble.net/image.185631766.5316/flat,800x800,070,f.jpg&quot; rel=&quot;noreferrer&quot;&gt;like the standard model&lt;/a&gt; or should we doubt them.   That's a philosophical can of worms that I'd rather not open, but I can say this, if you can't follow the science, perhaps you shouldn't take a side.  Your time would be better spent learning than doubting.   There is no wisdom in naked skepticism.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's something many skeptics would be wise to learn.   Skepticism is both great and useless at the same time.   Bart Simpson's a skeptic.   The dumbest kid in the class can say &quot;I'm skeptical about that&quot;, and he can answer every question with those 4 words, but he'll never get any smarter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Applied skepticism is where it's at, and to apply skepticism, you need to understand the argument(s).  Good skepticism requires understanding and, after understanding the argument, then you can intelligently apply skepticism.   Empty doubt is useless.  Good skeptics need to be smart.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is one argument as to why man made climate science is likely true.   Because there are no good skeptical arguments against it.   Urban heat island - debunked.   Cosmic rays - studied, but no evidence found.   It's the sun?   No, we measure solar output, we'd know.   Mars is getting warmer?  That's incidental.   We're still warming from the last ice age - actually, the opposite is true, we're in a cooling period.  Got any others?   The climate change deniers have figured out that they don't need science to sell their seeds of doubt, they're just selling doubt, but selling doubt isn't a scientific argument.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What evidence is backing the claim that the C02 is the main cause of&#xA;  climate change?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A quick google search will answer this question for you.  Read some of those, and if you still have questions, come back and ask.   This really, really, really has been answered, again and again and again and again.   If you have trouble, I can post some explanations for you.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;CO2 levels have been going up and down for as long as we can look at&#xA;  them without human intervention. Eg this NASA graph spanning 400.000&#xA;  years&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The primary drivers are the milankovich cycle, which leads to the ice-age cycle and feedback mechanisms.  Colder oceans absorb more CO2, warmer oceans release CO2.   CO2 and global temperature have an effect on each other, each driving the other forward or backward depending on how much ice-cover the Earth has.   This is a well understood feedback mechanism that in no way contradicts climate change theory, in fact, they go hand in hand.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;global temperature is still inside the bounds of normal cyclical&#xA;  Halocene variations (as seen on wikipedia)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes, but the &lt;strong&gt;rate of increase&lt;/strong&gt; is NOT within the bounds of normal Holocene variation.   Also, there is a relation between &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles#Present_and_future_conditions&quot; rel=&quot;noreferrer&quot;&gt;northern hemisphere summer insolation&lt;/a&gt; and temperature.   The direction of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles#/media/File:InsolationSummerSolstice65N.png&quot; rel=&quot;noreferrer&quot;&gt;Northern Hemisphere summer insolation is downward right now&lt;/a&gt;.  That suggests, without human influence, Earth should be cooling right now, it's not.  It's warming rapidly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can say &quot;but the Earth was just as warm 7,000 years ago&quot;, and that's about right, but the orbit was different and Earth should have been warmer 7,000 years ago.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;earth temperature has been going up and down for millions of years,&#xA;  obviously without human intervention, as seen on the same wikipedia&#xA;  page&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Hundreds of thousands of years:   &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;noreferrer&quot;&gt;Milankovich Cycles&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2/5/10/50/100 million years . . . &lt;a href=&quot;https://earthobservatory.nasa.gov/IOTD/view.php?id=4073&quot; rel=&quot;noreferrer&quot;&gt;Isthmus of Panama&lt;/a&gt;, &lt;a href=&quot;http://www.global-climate-change.org.uk/2-6-1.php&quot; rel=&quot;noreferrer&quot;&gt;Himalayas&lt;/a&gt;, &lt;a href=&quot;https://discoveringantarctica.org.uk/oceans-atmosphere-landscape/ice-land-and-sea/tectonic-history-into-the-deep-freeze/&quot; rel=&quot;noreferrer&quot;&gt;drifting of Antarctica&lt;/a&gt;, &lt;a href=&quot;https://www.livescience.com/49361-greenland-ice-glacier-formation.html&quot; rel=&quot;noreferrer&quot;&gt;Glaciation of Greenland&lt;/a&gt;, &lt;a href=&quot;https://www.scientificamerican.com/article/can-the-fern-that-cooled-the-planet-do-it-again/&quot; rel=&quot;noreferrer&quot;&gt;variation in plant life&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There can be many causes of natural climate change.   One of the ways we know that the current climate change is man made is that we can rule out causes, for example, ocean currents didn't suddenly change in the late 80s.  No new land bridges formed.   Causes are testable and causes have signatures.  CO2 or greenhouse gas driven climate change has a measurable signature.   It's not just that temperature is rising but where it's rising that helps answer these questions, poles vs equator, land vs oceans, upper atmosphere vs lower.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;scientists usually reiterate the first four facts&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;If you'd read even one scientific study, you'd know this isn't true.  Journalists might mostly reiterate your first four facts, not scientists.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;we know they work because they explain past changes, but this not a&#xA;  very strong point since those models have been calibrated using past&#xA;  data&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There's a principal in science called the double-blind study, where you set up two equal experiments, with one variation and you don't know which experiment has the variation and you study the effects.    This is a good scientific approach but it's not always possible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can study the effects of smoking by letting one group smoke and another group not and compare the two groups, but we can't build other Earths to study one with burning fossil fuels and one without - models are all we have.   How accurately the models predict what will happen by 2100 is hard to say, but inaccurate models are better than none.   Take a financial advisory firm that runs models and one that doesn't - and you tell me which one will be right more often.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's also much more consistency with planet Earth than there is with financial models.  The solar energy the Earth receives year to year varies by less than 0.1%.  Global could cover varies by perhaps 1%-2% year to year.  Snowfall cover varies maybe a little more, volcanic ash comes and goes, but generally leaves the atmosphere pretty quickly, even the largest volcanoes only trigger cooling for a small number of years.   The Earth absorbs heat from sunshine with a small percentage coming from internal heat and volcanoes and it loses heat by radiation.   There are thermodynamic laws that govern heat transfer.    That means the Earth is pretty consistent, having roughly the same orbit around the same star.   By comparison, financial models try to estimate something that's a few orders of magnitude more volatile.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Modeling isn't easy, but it beats blind guessing like the Patriots beating the Jets.   That's true in both studying climate change and in finance.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;So, how do we know it's man-made?&lt;br&gt;&#xA;Look at the signature.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth is warmed by the sun during the day and it radiates energy away at night.   The atmosphere acts like a shield, blocking some of the solar energy from reaching the surface and a blanket catching some of the radiation leaving Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Climate change gases like SO2 and very fine volcanic ash thicken the shield, cooling the Earth - see &lt;a href=&quot;https://en.wikipedia.org/wiki/Year_Without_a_Summer&quot; rel=&quot;noreferrer&quot;&gt;year without summer&lt;/a&gt;.   Climate change gases like CO2 thicken the blanket.   Water is also a greenhouse gas so where CO2 has the biggest effect is low absolute humidity regions like the poles.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other changes, like albedo, the effect is in visible light, not infra-red.   Ocean current changes are easy to detect because the effects are visible on location.   A stronger mid-atlantic current = warmer European winter.   The climate effects of El Nino, which warms the Earth, are many, but they are well documented.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Heat-trapping greenhouse gas has a signature.   The lower atmosphere warms, the upper atmosphere cools, the tropopause rises and the troposphere loses mass.   The warming can be modeled based on greenhouse gas to be largely polar and the comparing temperature by time of day, the Earth warms most at night, where a hotter sun would do the opposite and warm the Earth during the day and that's where you'd see the larger variation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your question implies that scientists ignore all the other possibilities.   Nothing could be further from the Truth.   Scientists (on average) appreciate possibilities and will rarely dismiss valid alternative explanations.   While the theory was first proposed in the 1900s, modern climate change theory had a rebirth in the 1950s, and was the subject of much study through the 60s, 70s and 80s.   It was met, not with immediate acceptance, but decades of skepticism.   It's only now accepted because the evidence in favor is very strong and the evidence for alternate explanations is hovering close to zero.   Decades of research, models that aren't perfect, but fit both matching what's happened so far and going backward, and the signature of the warming matching what is expected from CO2 and the counter theories all failing.    The evidence is very very strong.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All it would take to disprove manmade climate change theory is one unexplained cold year - just one.  One year like the 1970s without a volcano to cause it and the theory is dead.  That hasn't happened.  We've had nothing but warm years for a few decades now.    You could also disprove it by showing a signature that doesn't fit with CO2.  The opportunity (and funding) to disprove climate change is enormous, but you can't disprove a truth, not scientifically.   If it was false, it wouldn't be that hard to show scientific evidence that disproved it.  It's not like this is Rosalind Franklin who worked out how to take photographs of the DNA molecule and she was reluctant to share them with other scientists who'd take the credit for her work.  This is the Earth.  The data, the evidence is out there.  The means to disprove man made climate change - if it was disprovable, are available, and the funding to disprove it is available and significant and they have nothing.   All the evidence still points towards man made climate change theory being right.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(too long?  too preachy?)&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2018-02-22T10:54:01.237" LastActivityDate="2018-02-22T10:54:01.237" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13421" PostTypeId="2" ParentId="13416" CreationDate="2018-02-22T12:11:47.287" Score="3" Body="&lt;p&gt;I honestly wish I could come up with a better answer for this question but the original article is so horrible I'm not sure where to even begin responding to it. For starters, it's published in a medical journal and if the abstract is anything to go by, the paper is constantly comparing the earth to the body. Quote: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Just like the function of the thermal isolation of subcutaneous fatty tissue under the dermis of human skin, it keeps the internal heat within the organism so it won't be transferred to the skin's surface and be lost maintaining body temperature at low temperatures&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This may be true in humans, I'm not sure, but oil, coal and gas reserves make up a &lt;em&gt;tiny&lt;/em&gt; portion of the earth's crust so this analogy fails on every level. Using their logic you could argue that valleys contribute to global warming as well since they cut into the crust and I'm sure we'd all agree that is arrant nonsense!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To paraphrase the article linked above by @david, the authors try and argue that it's the act of drilling holes and making cracks in the earths crust that is the main force of climate change.&lt;/p&gt;&#xA;" OwnerUserId="12282" LastEditorUserId="12282" LastEditDate="2018-02-22T23:17:10.723" LastActivityDate="2018-02-22T23:17:10.723" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13422" PostTypeId="1" AcceptedAnswerId="13430" CreationDate="2018-02-22T13:22:21.077" Score="3" ViewCount="198" Body="&lt;p&gt;The fossil tooth was found western South Dakota in the early 1980s.&#xA;I can't be sure on the location.  It might have been collected from Belle Reservoir, near Belle Fourche, Butte County, South Dakota, USA.&lt;br&gt;&#xA;What type of mammal does this fossil tooth belong to?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oxQ5I.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oxQ5I.jpg&quot; alt=&quot;Top view of fossil tooth&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Qk1Zy.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Qk1Zy.jpg&quot; alt=&quot;Side view of Fossil tooth&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T09:15:20.767" LastActivityDate="2019-08-29T09:15:20.767" Title="What type of mammal does this fossil tooth belong to?" Tags="|fossils|paleontology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13424" PostTypeId="1" CreationDate="2018-02-22T20:49:20.600" Score="2" ViewCount="192" Body="&lt;p&gt;How does these rainbows water drops differ? I know it has to do with the size of water drops refracting light.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a formula that determines the type of rainbow?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DgnU9.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DgnU9.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XAVMe.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XAVMe.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Sw39f.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Sw39f.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Icebow&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0SgF6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0SgF6.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unlike this &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9180/what-actually-happens-to-reduce-the-perceived-color-in-a-white-rainbow-or-fog?noredirect=1&amp;amp;lq=1&quot;&gt;questions&lt;/a&gt; answer it does not illustrate how the reduction of water drops make less color. Also this ice bow does not follow this rule of thumb in that question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Illustrations would be great!&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2018-03-29T20:46:12.193" LastActivityDate="2018-03-29T20:46:12.193" Title="Why are all rainbows are not the same?" Tags="|atmosphere|geophysics|light|rain|" AnswerCount="0" CommentCount="7" ClosedDate="2018-02-23T21:26:27.533" ContentLicense="CC BY-SA 3.0" />
  <row Id="13425" PostTypeId="1" AcceptedAnswerId="13426" CreationDate="2018-02-22T21:22:19.830" Score="5" ViewCount="584" Body="&lt;p&gt;If hydrogen is the lightest gas known, would it rise making the outermost part of the atmosphere mostly hydrogen?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Images to associate with your answer would be much appreciated. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="12057" LastEditDate="2018-02-22T21:43:03.770" LastActivityDate="2018-02-23T14:32:20.587" Title="How high is too high for hydrogen to rise?" Tags="|atmosphere|gas|gravity|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13426" PostTypeId="2" ParentId="13425" CreationDate="2018-02-22T21:39:26.190" Score="8" Body="&lt;p&gt;I had a &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13144/why-air-do-not-suffer-density-stratification-of-its-gaseous-components&quot;&gt;similar question&lt;/a&gt;, and then I learned that at the molecular level it is diffusion what dominates, that means that despite Hydrogen is lighter, it won't rise to the top of the atmosphere. Flotation as we visualize it doesn't really work at the molecular level (because it is overcome by chemical diffusion).&#xA;Therefore, the Hydrogen in the atmosphere is evenly distributed trough it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To clarify it further, a parcel of hydrogen would indeed rise, but as soon as it gets diluted in the surrounding air, the buoyancy of individual molecules/atoms would become negligible in comparison to the chemical diffusion that will take the atoms in any direction, not just upwards, leading to further dilution of the original molecules within the parcel throughout the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for why that's the case, let's me explain how I visualize it: Imagine you put two a thousand million ping-pong balls in the middle of the Pacific ocean. Half of them with a piece of Iron inside. If you put a magnet in the coast of Mexico, you would expect all the balls with the piece of iron to end up in Mexico. However, the forces of the wind and waves hitting the balls in random ways is so much more powerful than the magnetic attraction in this case, that most likely the balls will end up all over the Pacific. In the same way, all molecules in the air are bouncing against each other with such a strength, that the fact that one is lighter than the other doesn't really play a role in the trajectory a molecule will follow on its journey trough the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In any case there is not much Hydrogen in the atmosphere, that &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;only contains a 0.00005 % of molecular Hydrogen&lt;/a&gt; (H2).&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-02-23T00:15:30.487" LastActivityDate="2018-02-23T00:15:30.487" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13427" PostTypeId="1" AcceptedAnswerId="15066" CreationDate="2018-02-23T00:18:47.277" Score="3" ViewCount="193" Body="&lt;p&gt;e.g. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A major earthquake hitting an area over which a large tropical cyclone is passing by (Haiti, Mexico (either coast), Taiwan/Japan/Philippines)&lt;/li&gt;&#xA;&lt;li&gt;Major tornado outbreak hitting an area inundated by wildfires (southeastern U.S. in November-December)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The text in brackets represents areas where I think such scenarios &lt;em&gt;could&lt;/em&gt; happen.&lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2018-09-10T06:33:59.783" Title="Have there ever been significant events of ecological or geological disasters occurring simultaneously alongside extreme meterological disasters?" Tags="|natural-disasters|extreme-weather|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13430" PostTypeId="2" ParentId="13422" CreationDate="2018-02-23T20:30:10.640" Score="5" Body="&lt;p&gt;It's an entelodont, South Dakota is famous for it's Oligocene mammalian faunas which include entelodonts such as Archaeotherium and Daeodon. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/exy5f.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/exy5f.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;here is an &lt;a href=&quot;http://i.ebayimg.com/images/i/181202162847-0-1/s-l1000.jpg&quot; rel=&quot;noreferrer&quot;&gt;http://i.ebayimg.com/images/i/181202162847-0-1/s-l1000.jpg&lt;/a&gt; for comparison:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/GCNDe.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GCNDe.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks to the guys at &lt;a href=&quot;http://www.thefossilforum.com/index.php?/topic/82219-what-is-this-north-american-megafauna-fossil-tooth/&quot; rel=&quot;noreferrer&quot;&gt;fossilforum&lt;/a&gt;, they knew in less than a day. this question could have stayed on here for a year so i was impatient. &lt;/p&gt;&#xA;" OwnerUserId="3315" LastActivityDate="2018-02-23T20:30:10.640" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13431" PostTypeId="2" ParentId="13427" CreationDate="2018-02-23T21:54:30.263" Score="1" Body="&lt;h1&gt;Yes.&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Here's a list of common disasters that associate with each other:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;A twister (tornado) that fused with a wildfire &lt;em&gt;(aka: a firenado)&lt;/em&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;A cyclone (Hurricane) that caused a tsunami &lt;em&gt;(common)&lt;/em&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;An earthquake in the ocean that caused a tsunami &lt;em&gt;(common)&lt;/em&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;...and probably several more. But many times such an occurrence is typical, and often happen; such as oceanic earthquakes and hurricanes causing tsunamis; However, some of them are less likely to happen; such as the 'firenado'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;A great example of a scenario you're asking to see is &lt;a href=&quot;https://www.cnn.com/2013/07/13/world/americas/hurricane-sandy-fast-facts/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hurricane Sandy&lt;/a&gt;'s effects on North America.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sandy was known to be one of the worst hurricanes ever recorded; damagewise, costwise, and wave height &lt;em&gt;(what you wanted to hear :D)&lt;/em&gt;. It has been recorded on CNN (the link added goes to the CNN article on Sandy) that its wave heights reached &lt;strong&gt;32.5 feet (roughly 9.9 meters) in height.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in conclusion; occurrences like this happen, and some of them are typically known to occur in some the circumstances listed above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(Information on Hurricane Sandy was grabbed from CNN)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(Information on the scenarios listed above were grabbed from google)&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="12057" LastActivityDate="2018-02-23T21:54:30.263" CommentCount="13" ContentLicense="CC BY-SA 3.0" />
  <row Id="13432" PostTypeId="1" AcceptedAnswerId="13433" CreationDate="2018-02-24T05:36:42.070" Score="12" ViewCount="2045" Body="&lt;p&gt;How fast can the Earth rotate and support life?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In prehistoric times, dinosaurs were so massive that archeologists wonder how they were not crushed under their own weight. Could a faster spinning Earth allow larger animals to exist?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could the slowing of Earth's rotation cause extinction among the larger animals but not the smaller animals?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://physics.stackexchange.com/questions/278117/how-fast-can-the-earth-spin-and-support-life&quot;&gt;https://physics.stackexchange.com/questions/278117/how-fast-can-the-earth-spin-and-support-life&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*Ignoring any environmental impacts&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2019-04-12T19:46:54.463" LastActivityDate="2019-10-31T15:13:52.563" Title="What is the fastest the Earth has ever spun?" Tags="|atmosphere|earth-history|planetary-science|earth-rotation|gravity|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="13433" PostTypeId="2" ParentId="13432" CreationDate="2018-02-24T06:50:20.710" Score="24" Body="&lt;p&gt;The speed of rotation of Earth is controlled by its angular momentum. And the conservation of angular momentum is a very serious law of physics (perhaps even stricter than conservation of mass). So in the same way that for the Earth to lose mass, that mass have to go somewhere. For the Earth to lose angular momentum, it'd have to go somewhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth's rotation can vary within a small range by rearranging the distribution of mass (changing the &lt;a href=&quot;https://en.wikipedia.org/wiki/Moment_of_inertia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Moment of inertia&lt;/a&gt;). That's why on ice ages the day was a few seconds longer, because large amounts of water that used to be on the ocean was piled in large ice sheets, so like in the classic example of a rotating ice skater, by moving mass (ice on Earth or the arms of the skater) away from the rotation axis, slows down the rotation speed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only other way for the Earth to significantly change its rotation speed is by losing &lt;a href=&quot;https://en.wikipedia.org/wiki/Angular_momentum&quot; rel=&quot;nofollow noreferrer&quot;&gt;angular momentum&lt;/a&gt;, and any imaginable event that could change significantly Earth's angular momentum over a period of 15 years would be so catastrophic that the change in rotation speed would be secondary. Such event would have to be something like the collision with a massive asteroid, the fly-by of planet-size celestial body, or the ejection of large amounts of mass by the explosion of gigantic natural nuclear reactors (all things that might have happened very early in Earth's history).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are however processes at work today that are slowly stealing Earth's angular momentum. The most important one is tides. Tides produce bulges of water around Earth that rotate slower than Earth, as in this picture (from &lt;a href=&quot;https://en.wikipedia.org/wiki/Tide&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/0pRS7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0pRS7.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, to keep the bulges in place the water have to be constantly flowing into those bulges moving against Earth's rotation and slowing it down by friction. The lost angular momentum goes mostly to the moon that accelerate on its orbit, therefore moving away from us &lt;a href=&quot;https://www.scientificamerican.com/article/earth-rotation-summer-solstice/&quot; rel=&quot;nofollow noreferrer&quot;&gt;3.8 centimeters per year&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This process makes the day longer &lt;a href=&quot;https://www.scientificamerican.com/article/earth-rotation-summer-solstice/&quot; rel=&quot;nofollow noreferrer&quot;&gt;1.7 milliseconds per century&lt;/a&gt;, something that is not a lot even at geological times scales. It is equivalent to 17 seconds per million of years. But even that small amount adds up to almost one full hour since the start of the Jurassic (201 Ma ago). But the change is so slow that animals would have plenty of time to adapt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I would say that any explanation of how the dinosaurs supported their own weight have nothing to do with changes in Earth rotation speed. Also, I think you are overestimating the impact of the rotation speed on the perceived weight. If we make the numbers, the centripetal acceleration due to rotation at the equator is&#xA;&lt;span class=&quot;math-container&quot;&gt;$$a_\mathrm c=\frac{v^2}r=\frac{(462\ \mathrm{m/s})^2}{6\,378\,100\ \mathrm m}=0.0336\ \mathrm{m/s^2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Equivalent to a 0.3% of the acceleration of gravity. Therefore, even if the Earth were to stop completely, a dinosaur of 1000 kg would feel only ~3 kg heavier.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Said that, if we go to the very hypothetical case you say, a slow down wouldn't make much of a difference (ignoring any environmental impacts of having a one-year-long day).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And for how fast the can Earth spin and support life? I think nobody can really answer that question, as we don't know what conditions life can endure. But if you make the Earth spin faster, the centripetal acceleration grows as the speed squared, therefore it wouldn't take too much to make the centripetal acceleration equal to the acceleration of gravity, in which case objects in the equator would be weightless. In that case, Earth would lose its atmosphere and oceans, and further speed-up would start ejecting rocks into space. By rearranging the above equation we can get that critical speed, and it would be:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$v_\mathrm c=\sqrt{rg}=\sqrt{6\,378\,100\mathrm m\times9.8\ \mathrm{m/s^2}}=7\,906\ \mathrm{m/s}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is 17 times the current speed, equivalent to a day of one hour and 24 minutes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, for your  question: What is the fastest the Earth has ever spun? It depends. If we consider it after the main change in angular momentum associated to the formation of the Moon &lt;a href=&quot;https://en.wikipedia.org/wiki/Moon#Formation&quot; rel=&quot;nofollow noreferrer&quot;&gt;4.51 billion years ago&lt;/a&gt;, we can just extrapolate those 17 seconds per million years (this is not the most precise as there were no oceans then, but it is a fair first approximation), and we get about 21 hours, so that the day at that time was only about &lt;strong&gt;three hours&lt;/strong&gt; long.&#xA;Careful calculations for the length of the day in the proto-Earth before the formation of the moon lead to a day of 5.8 hours (see &lt;a href=&quot;https://arxiv.org/pdf/1001.4243.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt;, line 358)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an anecdotal note, the fact that this number is quite close to the critical velocity, have made some people think that &lt;a href=&quot;https://arxiv.org/pdf/1001.4243.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;the explosion of a natural nuclear reactor could have been enough to give the extra kick to eject the whole Moon from the surface&lt;/a&gt;. Something that would explain why the composition of the Moon is so remarkably similar to that of Earth by recent analysis, challenging the &lt;a href=&quot;https://en.wikipedia.org/wiki/Giant-impact_hypothesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;theory of formation by a collision&lt;/a&gt; with &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Theia_(planet)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Theia&lt;/a&gt;&quot; a hypothetical Mars-sized body. Although, there are other recent theories with an alternative solution to this problem, such as the &lt;a href=&quot;https://www.ted.com/talks/sarah_t_stewart_where_did_the_moon_come_from_a_new_theory#t-658680&quot; rel=&quot;nofollow noreferrer&quot;&gt;synestia theory&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, it would be wrong to restrict all possible changes of rotation speed only to surface processes or interactions to other celestial bodies. It could also be possible that mass redistribution in the Earth's interior could affect rotation speed. Events like the &lt;a href=&quot;https://en.wikipedia.org/wiki/Iron_catastrophe&quot; rel=&quot;nofollow noreferrer&quot;&gt;iron catastrophe&lt;/a&gt; would have increased the rotation speed, and other mass redistribution events could have happened or might be happening, but this is just speculation. Studying such processes is extremely difficult, we know very little about the dynamics of the Earth interior, and it will be extremely hard to prove or falsify theories concerning such internal mass redistribution events. &lt;a href=&quot;https://worldbuilding.stackexchange.com/a/139530/61556&quot;&gt;This answers&lt;/a&gt; and and others in the same question have some ideas of how the angular velocity of a planet could change.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-04-12T19:46:50.210" LastActivityDate="2019-04-12T19:46:50.210" CommentCount="18" ContentLicense="CC BY-SA 4.0" />
  <row Id="13434" PostTypeId="1" AcceptedAnswerId="13437" CreationDate="2018-02-24T14:24:46.233" Score="3" ViewCount="187" Body="&lt;p&gt;Let’s say I have got 15 CMIP5 models’ outputs of a given variable e.g. temperature, for RCP6.5 (2020-2100) run.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to plot how the temperature will change in the future 2020-2100 (scatter plot, x = time and y = temperature).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Instead of showing all the 15 models outputs can I just simply show the CMIP5 multi-model ensemble average? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;i.e. instead of 15 lines into one plot I show only one line (the average).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this correct?&#xA;Will a reviewer reject this approach?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="11493" LastActivityDate="2018-02-25T16:57:24.233" Title="CMIP5 multi-model ensemble, can it be shown as ensemble average?" Tags="|meteorology|climate-change|climate|climate-models|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13437" PostTypeId="2" ParentId="13434" CreationDate="2018-02-24T21:45:15.233" Score="3" Body="&lt;p&gt;That is valid. You can show the average (or median if there is a reason to get rid of outliers), but it would be VERY misleading and arguably wrong if you don't show also the uncertainty associated  with that mean solution.&#xA;However, the whole point of getting the mean of many values is to reduce  the uncertainty. Therefore, just plotting a shaded area covering the range over which the original lines were distributed, would be an overestimation of the uncertainty (here I'm assuming that each original line have no uncertainty, which is wrong, but if you have that uncertainty data it can also be included).&#xA;A standard way to estimate the uncertainty of the average of many lines (a.k.a Time series) is calculating &lt;a href=&quot;https://en.wikipedia.org/wiki/Bootstrapping_%28statistics%29#Deriving_confidence_intervals_from_the_bootstrap_distribution&quot; rel=&quot;nofollow noreferrer&quot;&gt;bootstrap confidence intervals&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is an example from a &lt;a href=&quot;https://www.the-cryosphere-discuss.net/tc-2017-270/tc-2017-270.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt; I recently submitted:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/QQTww.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QQTww.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mean of all those black lines is the blue line. To expose the spread of the data I decided to show all the original lines. But, if I were to show this to a general audience, I would get rid of the thin black lines and show the mean (blue) and the confidence intervals (pink shades).&#xA;Those shades mean that with a 90% confidence the mean should fall within the dark pink shading, and with a 99% confidence within the light pink shading. Giving a sense of how much you can trust the blue line.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-02-25T16:57:24.233" LastActivityDate="2018-02-25T16:57:24.233" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13440" PostTypeId="1" AcceptedAnswerId="16376" CreationDate="2018-02-25T13:06:34.477" Score="7" ViewCount="859" Body="&lt;p&gt;In various land cover classification systems, trees are also categorised on the basis of broadleaf or needleleaf. Can someone please tell me the mechanism through which satellites detect this leaf type? Does normalized difference vegetation index (NDVI) plays any role in it? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, in GlobCover project, the land cover maps that were generated consisted of 23 land cover classes including classes like broadleaf forests and needleleaf forest. There, the satellite sensors collected data on various phenological metrics like NDVI, etc. and averaged them temporarily to get a single value for such metrics. But not much has been given in &lt;a href=&quot;http://due.esrin.esa.int/files/GLOBCOVER2009_Validation_Report_2.2.pdf&quot; rel=&quot;noreferrer&quot;&gt;http://due.esrin.esa.int/files/GLOBCOVER2009_Validation_Report_2.2.pdf&lt;/a&gt; about what all phenological metrics were computed. So basically my question is, how did the MERIS sensor differentiated between broadleaf forest and needleleaf forest?&lt;/p&gt;&#xA;" OwnerUserId="7753" LastEditorUserId="15341" LastEditDate="2019-03-02T23:48:50.993" LastActivityDate="2019-03-19T05:22:57.663" Title="How do optical satellites detect different leaf types?" Tags="|remote-sensing|forest|ndvi|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="13441" PostTypeId="2" ParentId="13440" CreationDate="2018-02-25T15:35:23.083" Score="5" Body="&lt;p&gt;In general, no, NDVI is not used to derive vegetation type.  NDVI is useful for studying &lt;a href=&quot;https://pubs.er.usgs.gov/publication/fs20143052&quot; rel=&quot;nofollow noreferrer&quot;&gt;phenology&lt;/a&gt;, but it won't tell you the type of plant that is being remotely sensed.  Good land cover systems use a variety of data sources to derive general plant type (e.g. conifer vs deciduous).  For instance, the &lt;a href=&quot;https://landcover.usgs.gov/uslandcover.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Land Class Database (NLCD) description&lt;/a&gt; states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The National Land Cover Database products are created through a cooperative project conducted by the Multi-Resolution Land Characteristics (MRLC) Consortium. The MRLC Consortium is a partnership of federal agencies, consisting of the U.S. Geological Survey (USGS), the National Oceanic and Atmospheric Administration (NOAA), the U.S. Environmental Protection Agency (EPA), the U.S. Department of Agriculture (USDA) Natural Resources Conservation Service (NRCS, the U.S. Forest Service (USFS), the National Park Service (NPS), the U.S. Fish and Wildlife Service (FWS), the Bureau of Land Management (BLM), the National Aeronautics and Space Administration, and the Office of Surface Mining (OSM).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Relying on satellite data alone causes problems with classification (e.g. see &lt;a href=&quot;https://remote-sensing-agriculture.blogspot.com/2013/04/vegetation-classification-coniferous.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;http://www.isprs.org/proceedings/XXXV/congress/comm7/papers/181.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;).  However, there have been attempts to derive Leaf Area Index (LAI) from NDVI.  LAI can then be used over long periods to attempt to distinguish coniferous from deciduous forests (e.g. by comparing winter to summer).  Though, there are many sources of error when making these types of assumptions.  &lt;a href=&quot;https://earthobservatory.nasa.gov/Features/LAI/LAI3.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; is a nice discussion of this, which notes that deriving LAI from NDVI is getting better, but there are still limitations.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2018-02-25T19:18:48.400" LastActivityDate="2018-02-25T19:18:48.400" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13442" PostTypeId="1" CreationDate="2018-02-25T17:59:30.690" Score="6" ViewCount="242" Body="&lt;p&gt;Consider the case of two weather systems of different temperatures hitting the Andes Mountains from the west: After traveling a long distance over the Pacific ocean I would expect the air in both systems to be water saturated (i.e. Relative Humidity of 100%). However, the warmer system will be carrying more water and it will drop more water over the mountains (correct me if I got something wrong up to this point).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now: &lt;strong&gt;Will the precipitation happen over the same elevation range?&lt;/strong&gt; Or it will start to happen at lower/higher elevations?. &lt;strong&gt;Will the point of maximum precipitation stay the same?&lt;/strong&gt; Or it will migrate upwards/downwards?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In case particular details are needed to answer this question, I'll describe now my main area of interest, that correspond to the Patagonian icefields, in the southern tip of South America between latitudes 46 to 51° South, roughly 500 km in the north-south direction. The area corresponds to the red box in the following world map:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UAR2m.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UAR2m.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The size of the area would put it in the the upper boundary of the mesoscale meteorology. However, topography gradients can vary quite a bit within the domain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following image show how the area looks from above, with a sat image on the left (where the ice extent is clear) and the topography on the right:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Nd6EM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Nd6EM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have averaged the above elevation model in the north-south direction to obtain the average topography profile that Westerlies will face when hitting the mountains from the West (predominant winds come from between W and NW direction). This is how it looks:&lt;br&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/eOCsf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eOCsf.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The red lines (40 km apart) indicate roughly the currently ice covered longitudinal band. To the west of it, liquid precipitation dominates and there is no permanent ice cover. To the east, there is very little precipitation (dry pampas) and therefore no ice cover either.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The tree line in the area is usually between 400 and 600 m of elevation, represented by the green lines in the graph above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mean wind speed (&lt;a href=&quot;https://eosweb.larc.nasa.gov/cgi-bin/sse/global.cgi&quot; rel=&quot;nofollow noreferrer&quot;&gt;from a 22 year average dataset&lt;/a&gt;) when the winds hit the land is between 7 and 8 m/s (25-29 km/h), as show by the shading and contours in this figure:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/PkYLn.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PkYLn.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the same 22-year average dataset. The typical 10-meter air temperature on the ocean just before hitting the land is between 6 and 7 °C.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-02-28T06:29:48.113" LastActivityDate="2018-02-28T06:29:48.113" Title="How does temperature impact the elevation distribution of orographic precipitation?" Tags="|atmosphere|atmosphere-modelling|precipitation|orography|" AnswerCount="1" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="13445" PostTypeId="2" ParentId="13217" CreationDate="2018-02-25T21:21:44.107" Score="5" Body="&lt;p&gt;Let's clear up the terminology first:&lt;/p&gt;&#xA;&lt;h3&gt;trench&lt;/h3&gt;&#xA;&lt;p&gt;A &lt;em&gt;trench&lt;/em&gt;, as @bon has described in their answer, is formed where tectonic plates move &lt;strong&gt;towards each other&lt;/strong&gt; and one of the plates is subducted under the other. @bon has also provided an illuminating illustration. The German term for an &lt;a href=&quot;https://en.wikipedia.org/wiki/Oceanic_trench&quot; rel=&quot;noreferrer&quot;&gt;oceanic trench&lt;/a&gt; is &lt;em&gt;&lt;a href=&quot;https://de.wikipedia.org/wiki/Tiefseerinne&quot; rel=&quot;noreferrer&quot;&gt;Tiefseerinne&lt;/a&gt;&lt;/em&gt; (literally &amp;quot;deep sea groove&amp;quot;).&lt;/p&gt;&#xA;&lt;h3&gt;rift-valley or &lt;em&gt;graben&lt;/em&gt;&lt;/h3&gt;&#xA;&lt;p&gt;A &lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Graben&quot; rel=&quot;noreferrer&quot;&gt;graben&lt;/a&gt;&lt;/em&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Rift_valley&quot; rel=&quot;noreferrer&quot;&gt;rift valley&lt;/a&gt; is formed where tectonic plates move &lt;strong&gt;away from each other&lt;/strong&gt; and part of the broken crust sinks. The illustration below is from Wikipedia. The German term for a &lt;em&gt;graben&lt;/em&gt; is &lt;em&gt;Graben&lt;/em&gt; (literally &amp;quot;trench&amp;quot;).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IAX87.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IAX87.png&quot; alt=&quot;Graben&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now that we know the terminology, we can look at the Mid-Atlantic Ridge.&lt;/p&gt;&#xA;&lt;h3&gt;Mid-Atlantic Ridge&lt;/h3&gt;&#xA;&lt;p&gt;The Mid-Atlantic Ridge has been created by &lt;a href=&quot;https://en.wikipedia.org/wiki/Seafloor_spreading&quot; rel=&quot;noreferrer&quot;&gt;seafloor spreading&lt;/a&gt;: the plates drift apart and the rift is filled with magma from below. The resulting new crust is warmer than the older material surrounding it and therefore has higher buoyancy: it floats more easily and rests higher on the magma below, forming a ridge in relation to the colder, older, more heavy material around it.&lt;/p&gt;&#xA;&lt;p&gt;You can see this beautifully in the second illustration that @bon has provided: The crust is not thicker under the rift, rather it floats up.&lt;/p&gt;&#xA;&lt;p&gt;So the ridge is a ridge, not a trench, but the rift valley along its length is not a trench either, but a &lt;em&gt;graben&lt;/em&gt;: it has been formed by tectonic plates moving away from each other and parts of the separating ridge breaking off its edge and sinking into the rift.&lt;/p&gt;&#xA;" OwnerUserId="12307" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-02-25T21:35:46.527" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13446" PostTypeId="1" AcceptedAnswerId="13450" CreationDate="2018-02-25T21:58:57.293" Score="19" ViewCount="15642" Body="&lt;p&gt;I have done some research online, and I've found out that Antarctica has the calmest winds (lowest maximum wind speed) recorded on Earth. However, it is uninhabitable for human life. Other very calm areas are the &lt;a href=&quot;https://en.wikipedia.org/wiki/Doldrums&quot; rel=&quot;nofollow noreferrer&quot;&gt;doldrums&lt;/a&gt;, but they are over water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, I would like to know: &lt;strong&gt;What is the calmest place on Earth that is on or over land other than Antarctica?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS: I'm also pondering &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13452/what-is-the-highest-chain-of-balloons-possible&quot;&gt;this question about balloon chains&lt;/a&gt;, so I'm also interested in the places with the calmest overall wind column all the way from the troposphere to the mesosphere.&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="11908" LastEditDate="2019-03-04T00:30:58.567" LastActivityDate="2019-03-04T00:30:58.567" Title="Where is the calmest place on Earth?" Tags="|meteorology|atmosphere|geophysics|climate|geography|" AnswerCount="2" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="13448" PostTypeId="1" CreationDate="2018-02-26T00:37:35.327" Score="3" ViewCount="62" Body="&lt;p&gt;Where I can find a graph of the apparent rotation of the illuminated portion of the moon against the horizon in a single day? And is there a place where I can read about all the variations which dictate this angle?&lt;/p&gt;&#xA;" OwnerUserId="12308" LastEditorUserId="28050" LastEditDate="2018-03-02T12:51:43.573" LastActivityDate="2018-03-02T12:51:43.573" Title="Moon tilt against the horizon in a single day" Tags="|moon|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13449" PostTypeId="1" CreationDate="2018-02-26T01:30:37.653" Score="6" ViewCount="597" Body="&lt;p&gt;The myth goes that if a groundhog sees his shadow on Feb 2, six more weeks of winter are yet to come, but if he doesn't, spring is just around the corner.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am wondering if there is any science behind this myth, or perhaps an origin based on observations of actual weather patterns relating to the seasons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Never mind the groundhog, I am thinking about sky conditions and the seasons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Specifically, where I am in southern Ontario Canada, winter is usually at its coldest around the start of February. At this time of year we are often under an arctic high pressure &quot;dome&quot;; skies are often clear. As the cold gives way to milder weather, we often end up under the jetstream, or at least it sweeps back and forth over us, delivering a lot of stormy, wintry weather, after which the jetstream at the boundary of the polar air mass eventually retreats north and spring arrives.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this an oversimplification? If not, could this sort of pattern be the origin of the myth: generally clear skies mean winter remains settled in, more unsettled weather means winter is about to give way to spring?&lt;/p&gt;&#xA;" OwnerUserId="1210" LastActivityDate="2021-04-14T18:30:48.347" Title="Science behind the groundhog day myth" Tags="|meteorology|climate|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13450" PostTypeId="2" ParentId="13446" CreationDate="2018-02-26T01:45:58.407" Score="28" Body="&lt;p&gt;The main resistance that winds have to their movements comes from the topography and surface obstacles. Therefore, as a general rule the closer to the surface the less wind you will find. But I guess you are interested in the winds in areas clear of surface obstacles, otherwise the answer would a be a cave or a dense forest somewhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To figure out what is the calmest place on Earth wind-wise, we can use one of the &lt;a href=&quot;https://eosweb.larc.nasa.gov/cgi-bin/sse/global.cgi&quot; rel=&quot;nofollow noreferrer&quot;&gt;global datasets&lt;/a&gt; that NASA put together (initially to help with solar and wind energy planning). One of them is a &lt;a href=&quot;https://eosweb.larc.nasa.gov/sse/global/text/10yr_wspd50m&quot; rel=&quot;nofollow noreferrer&quot;&gt;10-year average (July 1983 - June 1993) of wind speed at 50 m above surface&lt;/a&gt;, ignoring the effect of trees and other non-topographic obstacles at a resolution of one degree (roughly 111 km or less).&#xA;I just loaded that dataset and searched for the minimum (and maximum) values, this is how it looks:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/5MDPf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5MDPf.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The minimum is not actually in Antarctica as your research suggested, but in the Amazon at longitude 68° west and latitude 0° (that's Brazil near the border with Colombia), with a mean wind speed of 1.55 m/s (5.6 km/h).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is an enlarged version of the most relevant area overlaid with a world map for easier interpretation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5aqy0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5aqy0.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In line to what was stated at the beginning, the maximum happens in an area were the lack of landmasses allow it to blow unimpeded around the world. And it happens at 60° W -52° S, reaching a mean wind speed of 12.62 m/s (45 km/h).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that this analysis is valid for broad areas. And of course individual weather stations at punctual locations can give different values. As for Antarctica, the winds there are mainly catabatic, therefore at the top of antarctic domes the average wind speed are very low. For example the average at &lt;a href=&quot;https://en.wikipedia.org/wiki/Dome_C&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dome C is 10.1 km/h&lt;/a&gt; and 9.4 km/h at &lt;a href=&quot;https://en.wikipedia.org/wiki/Dome_F&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dome F&lt;/a&gt;. However, those values are still bigger than what NASA's models suggest for the Amazonas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think the model I used here is reliable. As an exercise, you can see all the images that show up in a &lt;a href=&quot;https://www.google.ca/search?q=global%20mean%20wind%20speed&amp;amp;source=lnms&amp;amp;tbm=isch&amp;amp;sa=X&amp;amp;ved=0ahUKEwjK_cuHv8LZAhVN72MKHZn0AgAQ_AUICigB&amp;amp;biw=2133&amp;amp;bih=1036&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google search for &quot;global mean wind speed&quot;&lt;/a&gt; and you see that most images show a similar pattern, where Antarctica doesn't seem to contain the calmest place.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The model used to produce these datasets is a reanalysis, it means it takes all the weather data of the past (weather stations and satellite data) and attempts to reconstruct how exactly was the weather over the whole word. A similar kind of model takes only past weather data and attempts to predict how will be the weather over the whole world. That's a much more difficult problem, prone to bigger errors but that's actually what all the weather forecast we see on TV are based upon. One of the best global forecast models is called &lt;a href=&quot;http://www.emc.ncep.noaa.gov/index.php?branch=GFS&quot; rel=&quot;nofollow noreferrer&quot;&gt;GFS&lt;/a&gt; (Global Forecast System) that is produced by NOAA's &lt;a href=&quot;http://www.emc.ncep.noaa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Environmental Modeling Center&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To have a sense of how winds vary in different locations and altitudes you can explore the GFS  data using &lt;a href=&quot;https://earth.nullschool.net/#current/wind/surface/level/winkel3=0.00,0.00,243/loc=-68.156,-3.052&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cameron Beccario's amazing vizualization tool&lt;/a&gt;. There you can see the predicted global wind patterns all the way from the surface to more than 26 km of altitude (&lt;a href=&quot;https://earth.nullschool.net/about.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here you can find a table with referential equivalences between pressure levels in hPa and altitudes&lt;/a&gt;). Despite those are not multi-year averages, they are still very informative. Muze, the author of the question, pieced together a beautiful animated gif that show how the above mentioned visualization looks like for the elevation range of the jet streams at about 10 km of altitude (250 hPa):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/X02KD.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/X02KD.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Ugbde.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ugbde.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, I have to note that I've interpreted &quot;calmest&quot; as the &lt;strong&gt;minimum mean wind speed&lt;/strong&gt;. However, it would be sensible also to consider it as the place with the &lt;strong&gt;lowest maximum wind speed&lt;/strong&gt; or some other metric, that would perhaps change the picture described above. And maybe using that metric one of the Antarctic domes could be the &quot;calmest&quot; place. But I won't extend the answer further with any possible interpretation for &quot;calmest&quot;.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="5052" LastEditDate="2018-09-23T10:30:20.600" LastActivityDate="2018-09-23T10:30:20.600" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="13451" PostTypeId="2" ParentId="13448" CreationDate="2018-02-26T02:44:48.127" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://www.mooncalc.org&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mooncalc.org&lt;/a&gt; offers a pretty comprehensive set of tools for viewing the moon.  Click on the location you want, then drag the slider on top through the day to see which direction's sky the moon will be in (or times where it will not be visible).  And it shows the moon's shape you will see (I presume that's as viewed with nearest horizon down?)&lt;br&gt;&#xA;(For those interested, &lt;a href=&quot;http://suncalc.net&quot; rel=&quot;nofollow noreferrer&quot;&gt;suncalc.org&lt;/a&gt; is their sister site for the sun.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not an astronomer, but &lt;a href=&quot;https://svs.gsfc.nasa.gov/4404&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article from Goddard Space Flight Center&lt;/a&gt; looks like it offers a very solid discussion of &lt;a href=&quot;https://www.google.com/search?client=opera&amp;amp;q=define%20libration&amp;amp;sourceid=opera&amp;amp;ie=UTF-8&amp;amp;oe=UTF-8&quot; rel=&quot;nofollow noreferrer&quot;&gt;libration&lt;/a&gt;, and the causes due to moon's orbit, the relative location of the moon from different viewing locations, and the tilt of the Earth in relation to the sun.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2018-02-26T02:44:48.127" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13452" PostTypeId="1" AcceptedAnswerId="14262" CreationDate="2018-02-26T04:53:16.537" Score="1" ViewCount="620" Body="&lt;p&gt;The BU60-1 balloon attained an altitude of 53.0 km (32.9 mi; 173,900 ft). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Weather permitting, would a series of climbable balloons in a chain be able to be linked from the ground to that height of 53 km? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To gain altitude each balloon must be gradually bigger.&lt;br&gt;&#xA;At the bottom balloons would be made of more durable material.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XXVLB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XXVLB.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have found no record of this being done with higher tech weather balloons. &lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="6298" LastEditDate="2018-05-24T10:33:23.020" LastActivityDate="2018-05-24T10:33:23.020" Title="What is the highest balloons possible in a chain?" Tags="|meteorology|geophysics|wind|weather-forecasting|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="13453" PostTypeId="1" AcceptedAnswerId="13456" CreationDate="2018-02-26T07:43:45.437" Score="-3" ViewCount="2535" Body="&lt;p&gt;I am breaking this question and no longer making an effort in refining it with the exception of adding an associated link with the scenarios. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I always wondered if a devastating asteroid was predicted to impact the Earth where in the world would I have the highest chances of surviving the blast and short-term aftermath like seismic activity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which of these scenarios would have the best chances of survival?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Scenario 1.&lt;/strong&gt; In the air of some type blimp or aircraft on the opposite side of the Earth?&#xA;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/13528/how-is-radiation-dispersed-by-earths-atmosphere&quot;&gt;How is radiation dispersed by Earth&amp;#39;s atmosphere?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Scenario 2.&lt;/strong&gt; On or Underground in a cave?&#xA;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/13530/can-a-shock-wave-be-felt-all-the-way-around-the-earth&quot;&gt;Can a shock wave be felt all the way around the Earth?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Scenario 3.&lt;/strong&gt; In a submarine or capsule underwater?&#xA;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/13531/does-being-under-water-provide-any-protection-from-a-asteriod&quot;&gt;Does being under water provide any protection from a asteriod?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No point on Earth is truly safe without the known impact of the asteroid, but are there points on the Earth, even if you are on the other side, that you don't want to be like near fault lines?   &lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2018-03-03T19:39:59.937" LastActivityDate="2018-03-03T19:39:59.937" Title="Safest spots when an asteroid hits?" Tags="|geophysics|meteorite|natural-disasters|mass-extinction|" AnswerCount="1" CommentCount="3" ClosedDate="2018-03-03T02:48:58.347" ContentLicense="CC BY-SA 3.0" />
  <row Id="13454" PostTypeId="1" AcceptedAnswerId="13505" CreationDate="2018-02-26T08:58:22.043" Score="6" ViewCount="380" Body="&lt;p&gt;In my science-based novel, Moon colonists need to return to Earth to collect some rare or absent mineral(s) Ideally, something they could derive from seawater. Which minerals might they be...?&lt;/p&gt;&#xA;" OwnerUserId="12310" LastEditorUserId="725" LastEditDate="2018-02-28T22:32:00.453" LastActivityDate="2018-03-02T08:54:52.850" Title="Which Earth minerals would Moon colonists miss the most?" Tags="|geology|mineralogy|moon|economic-geology|earth-moon|" AnswerCount="5" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13455" PostTypeId="1" CreationDate="2018-02-26T09:27:16.530" Score="3" ViewCount="60" Body="&lt;p&gt;When analyzing hydrological and climatological timeseries/observations it is a common practice to compare statistics made on normal periods. As WMO calls them: &quot;WMO Climatological Normals&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These periods consist normally of 30 years of data. If you want to compare two normal periods with each other, let's say for example the periods 1951-1980 and 1981-2010.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now if we take averages for all the seasons in the period 1951-1980, the last month is December in this period. If we regard December, January, and February as a complete season/winter, it means that we have an incomplete winter at the end of the period 1951-1980. Now taking December to represent a whole winter, would be inaccurate. The monthly variations of a climatic parameter can vary greatly, and multiplying the December values by 3 wouldn't yield a result based on actual observations. Also making December the whole winter of 1980, would underestimate the real winter average. This would in turn affect the overall 30-year mean, by lowering it and giving a wrong picture of the actual seasonal mean in that normal period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Same goes for the beginning of the period 1981-2010, here we have January and February as an incomplete winter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now in order to get complete seasons in the intersections between the normal periods, wouldn't it be best to split the periods as follows: 1951-1980.11.30 and 1980.12.01-1990.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also it would be best to cut out December completely at the end of the period: 1980.12.01-1990.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So that it becomes: 1980.12.01-1990.11.30.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same goes for the last normal period: 1951-1980.11.30.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where we would cut out January and February of 1951 so that we get: 1951.03.01-1980.11.30.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this way we make sure we have complete seasons in both normal periods.&#xA;So if we also do comparisons of monthly averages: JAN-FEB-MAR..., we would still split up the periods in the same manner, in order to use the exact same periods for exact comparison with the seasonal averages.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However when we have split up the periods as follows: 1951.03.01-1980.11.30 and 1980.12.01-1990.11.30. Is it still normal in academic papers to say that we are comparing the normal periods 1951-1980 and 1981-2010, when there is actually a small overlap in the last?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this is not the normal procedure, what is the way to get around this? What do researchers normally do in this case?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition cutting of seasons/months in this manner yields an unequal number of months/seasons. The analysis might have data from a higher number of the month February compared to January. So the statistics from February are more reliable. Also a disadvantage of cutting out actual observation data, yields a loss of valuable observation data, which lowers the reliability of the statistics.&lt;/p&gt;&#xA;" OwnerUserId="12311" LastEditorUserId="6465" LastEditDate="2018-02-26T13:07:24.153" LastActivityDate="2018-02-26T13:07:24.153" Title="How to divide timeseries into normal periods in meteorology and climatology?" Tags="|meteorology|climate|climatology|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13456" PostTypeId="2" ParentId="13453" CreationDate="2018-02-26T11:49:36.600" Score="5" Body="&lt;p&gt;Being in a submarine in the ocean is not a good idea because if a large asteroid hits the ocean the shock wave created, and its energy, would be very large. If the submarine survives intact its occupants may not. The occupants could be thrown about so much they liquidize &amp;amp; turn into people puree.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly being airborne in a blimp or airplane would be problematic for the reasons you state.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Being on the opposite side of the world to the impact site, whether underground in a cave or on the Earth's surface, might be OK if you are far away from the coast so the tsunami wave from a asteroid hitting the ocean doesn't inundate you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for, as you state, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the crust of the Earth may change drastically with the whole cave sinking in the ocean or worse into the mantle&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;that won't happen. The &lt;a href=&quot;https://earthquake.usgs.gov/data/crust/&quot; rel=&quot;noreferrer&quot;&gt;Earth's crust&lt;/a&gt; is about 30 km thick. It can withstand some beating from an asteroid and it won't be sinking into the Mantle just because of an asteroid strike. A cave sinking into the ocean or being swamped by a tsunami might happen if the cave is near the coast and/or the asteroid strike is close by.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-02-26T11:49:36.600" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13457" PostTypeId="2" ParentId="8806" CreationDate="2018-02-26T12:48:55.093" Score="3" Body="&lt;p&gt;From my country there is indeed a saltwater river in the north western state of Rajasthan - &lt;a href=&quot;https://en.wikipedia.org/wiki/Luni_River&quot; rel=&quot;nofollow noreferrer&quot;&gt;Luni river&lt;/a&gt;. It is not salty from the point of it's origin but does become salty as it flows downstream. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a more complete description of the Luni river - &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://phedwater.rajasthan.gov.in/content/dam/doitassets/water/Ground%20Water/Pdf/PublicReports/Groundwater_Atlas/Basinwise/Luni%20River%20basin.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Luni River basin facts&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looking at this book - &lt;a href=&quot;https://books.google.co.in/books?id=tXP8CAAAQBAJ&amp;amp;pg=PA61&amp;amp;lpg=PA61&amp;amp;dq=luni%20river%20salt&amp;amp;source=bl&amp;amp;ots=eJhk5P94xA&amp;amp;sig=M7561zLTvUeU8Etb2i4NOI3pvgQ&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwi-gKayk8XZAhUE6Y8KHZOhB504ChDoAQhIMAc#v=onepage&amp;amp;q=luni%20river%20salt&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;Contributions to the ecology of halophytes&lt;/a&gt; one wonders on the accumulation of salt in these arid basins. Considering the basin is in proximity to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Rann_of_Kutch&quot; rel=&quot;nofollow noreferrer&quot;&gt;Great Rann of Kutch&lt;/a&gt; there were earlier conjectures that the atmosphere carried the salts as either particles or sprays of sea water. Wider acceptance of the origin of salt  these days is due to the atmospheric decomposition of feldspathic rocks and leaching by rain water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is probably the only river of consequence in the Western part of Rajasthan which forms part of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Thar_Desert&quot; rel=&quot;nofollow noreferrer&quot;&gt;Thar desert&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2018-02-27T03:51:45.773" LastActivityDate="2018-02-27T03:51:45.773" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13458" PostTypeId="5" CreationDate="2018-02-26T13:20:08.600" Score="0" Body="&lt;p&gt;Mineralogy studies all aspects of minerals, including:&lt;br&gt;&#xA;- their chemical composition&lt;br&gt;&#xA;- their crystal structure, i.e. the arrangement of atoms&lt;br&gt;&#xA;- their physical properties (density, hardness, etc.)&lt;br&gt;&#xA;These characteristics can be investigated using a wide range of analytical methods (microscopy, spectroscopy...), allowing for the identification and classification of mineral species.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="111" LastEditDate="2019-12-09T21:39:11.663" LastActivityDate="2019-12-09T21:39:11.663" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="13459" PostTypeId="4" CreationDate="2018-02-26T13:20:08.600" Score="0" Body="Questions relating to the scientific study and identification of minerals." OwnerUserId="12057" LastEditorUserId="18081" LastEditDate="2019-12-09T21:38:00.500" LastActivityDate="2019-12-09T21:38:00.500" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="13462" PostTypeId="1" CreationDate="2018-02-26T15:19:55.237" Score="3" ViewCount="149" Body="&lt;p&gt;Do subterranean habitat have climate system(s)? Could it be placed in any or all of the known ones: tropical, subtropical, temperate etc. ? Is it unique?&lt;/p&gt;&#xA;" OwnerUserId="12315" LastActivityDate="2018-02-26T15:19:55.237" Title="Subterranean Climate System?" Tags="|geography|geomorphology|climatology|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13464" PostTypeId="1" CreationDate="2018-02-26T16:01:31.680" Score="6" ViewCount="954" Body="&lt;p&gt;Is global warming linear in the sense that doubling the emission of Greenhouse gases will result in a doubling of global warming. Is there a threshold, i.e. is there are certain concentration of GHG where global warming is triggered and additional gases do not lead to a faster global warming? &lt;/p&gt;&#xA;" OwnerUserId="12318" LastActivityDate="2018-02-27T03:21:02.983" Title="Is global warming a linear process?" Tags="|climate-change|" AnswerCount="2" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="13465" PostTypeId="2" ParentId="8806" CreationDate="2018-02-26T16:06:15.173" Score="1" Body="&lt;p&gt;&lt;em&gt;&lt;strong&gt;NOTE:&lt;/strong&gt; Okay, I'm trying again to answer this question. I'll make sure to back it up with accurate information this time :)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a river in Arizona called the &lt;a href=&quot;https://saltriverraftingarizona.com/arizona-salt-river-actually-salty/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Salt River&lt;/a&gt;. In the article linked, it states the river is 'special' because It's salty.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are known to be more than just the Salt River; but there's an example of a saltwater river for you :)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;If you're still questioning my response, please read the article liked for more information.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="12057" LastEditorDisplayName="user1066" LastEditDate="2018-02-26T16:26:05.327" LastActivityDate="2018-02-26T16:26:05.327" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13466" PostTypeId="2" ParentId="13454" CreationDate="2018-02-26T16:33:21.057" Score="6" Body="&lt;p&gt;It is unlikely anything other than salt would be derived from sea water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.amnh.org/exhibitions/gold/incomparable-gold/world-gold-deposits&quot; rel=&quot;nofollow noreferrer&quot;&gt;The largest deposit of gold is dissolved within the worlds oceans&lt;/a&gt; - in terms of tonnes of metal. The problem with extracting the gold from sea water is the concentration is so low it is uneconomic to do so. It's why we keep mining hard rock sources of most metals. This problem exists for other metals dissolved in the worlds oceans. We are only just starting to mine minerals from the sea floor - see &lt;a href=&quot;http://www.nautilusminerals.com/IRM/content/default.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nautilus Minerals&lt;/a&gt; operations off the coast of &lt;a href=&quot;http://www.virginia.edu/colp/pdf/Nautilus-Minerals-Solwara-1-Project.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Papua New Guinea&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of Moon colonists requiring minerals from Earth, various salts or carbonates might be candidates. IF the colonists will be making steel, as opposed to just making iron, on the Moon they would need carbon, which would have to be sourced from Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Allied with the extremely low concentration of metals in sea water, the concentration of minerals/metals in some deposits on the Moon may be very low and it might be cheaper and/or easier to obtain the minerals/metals from Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other problem that might arise is that the mineral assemblages on the Moon may be different to that on Earth and while mining the minerals might be straight forward extracting the required/useful metals via metallurgical processes may be so problematic, or energy intensive, that it is easier &amp;amp; cheaper to obtain some minerals/metals from Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unlike on Earth, water in large quantities will not be able to be used for metallurgical processes, such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Froth_flotation&quot; rel=&quot;nofollow noreferrer&quot;&gt;froth flotation&lt;/a&gt;. Similarly, processes requiring the use of large quantities of oxygen will not be able to be used. New metallurgical processes may need to be developed to exploit lunar minerals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem for Moon colonists may not be the lack of minerals, but the lack of other types of resources to assist with metallurgical recovery or they may not be able to have metallurgical processes to exploit minerals on the Moon.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2018-02-27T11:02:33.490" LastActivityDate="2018-02-27T11:02:33.490" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13468" PostTypeId="5" CreationDate="2018-02-26T18:32:07.950" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2018-02-26T18:32:07.950" LastActivityDate="2018-02-26T18:32:07.950" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13469" PostTypeId="4" CreationDate="2018-02-26T18:32:07.950" Score="0" Body="Questions referring to the amount of salt in a body of water such as oceans. " OwnerUserId="12057" LastEditorUserId="111" LastEditDate="2018-02-26T23:04:43.900" LastActivityDate="2018-02-26T23:04:43.900" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13470" PostTypeId="2" ParentId="10008" CreationDate="2018-02-26T18:35:29.320" Score="2" Body="&lt;p&gt;In geological terms, &quot;dissection&quot; appears to refer to the creation of cuts in a landscape due to erosion e.g. by the flowing of streams. Dissection rate would then be the rate at which such cuts in the landscape form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://books.google.com/books?id=AIyIAAAAMAAJ&amp;amp;pg=PA221&amp;amp;lpg=PA221&amp;amp;dq=dissection+rate+geology&amp;amp;source=bl&amp;amp;ots=bFXfYFDmt3&amp;amp;sig=CiiKojDNHIkyQxzqVkBuSyL1Zr0&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwiVgpOLm8TZAhUKnOAKHXQQBMMQ6AEIUjAI#v=onepage&amp;amp;q=dissection%20rate%20geology&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://books.google.com/books?id=AIyIAAAAMAAJ&amp;amp;pg=PA221&amp;amp;lpg=PA221&amp;amp;dq=dissection+rate+geology&amp;amp;source=bl&amp;amp;ots=bFXfYFDmt3&amp;amp;sig=CiiKojDNHIkyQxzqVkBuSyL1Zr0&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwiVgpOLm8TZAhUKnOAKHXQQBMMQ6AEIUjAI#v=onepage&amp;amp;q=dissection%20rate%20geology&amp;amp;f=false&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12322" LastActivityDate="2018-02-26T18:35:29.320" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13471" PostTypeId="2" ParentId="13464" CreationDate="2018-02-26T18:49:52.483" Score="6" Body="&lt;p&gt;No. Consider water vapor. Water vapor is a greenhouse gas. As the temperature increases, more water is evaporated. Since water vapor is a greenhouse gas, the temperature will increase. Clouds, however, form from water vapor, reflect sunlight.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The earth is not as linear as people would like.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2018-02-26T18:49:52.483" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13472" PostTypeId="2" ParentId="13454" CreationDate="2018-02-26T23:29:21.180" Score="8" Body="&lt;p&gt;The composition of Moon rocks is pretty much the same as that of Earth. However, none of the processes that concentrate specific minerals in one location (i.e. into a mineral deposit useful for mining) exist on the Moon.  This is due to the lack of tectonic activity. Therefore in the Moon you would expect the rocks to be much more homogeneous than on Earth. Only maybe meteorites, their impact craters, and &lt;a href=&quot;https://science.nasa.gov/science-news/science-at-nasa/2014/24nov_imps&quot; rel=&quot;nofollow noreferrer&quot;&gt;ancient volcanic activity&lt;/a&gt; (as pointed by @userLTK) might have provided a way to concentrate some minerals in various places. So, due to this homogeneity, to get one gram of let's say copper, you would have to process hundreds of times more rock than would be needed in an Earth-based copper mine.&#xA;Also as Fred mentioned, there would be many challenges for mining in the Moon, but in the context of your plot those might have been solved. Having enough energy, you can probably get pretty much any mineral from the Moon (for example a mass spectrometer would be an effective but highly inefficient way to mine all the elements from within a piece of rock).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If your plot doesn't require that it be a mineral, I think what they might need the most is some sort of organic compound. Even with current technology &lt;a href=&quot;https://chemistry.stackexchange.com/questions/37708/can-all-compounds-that-plants-and-animals-produce-be-synthesized-in-a-lab&quot;&gt;there are many chemical compounds that can't be synthesized&lt;/a&gt;, and we rely on plants or animals to obtain them. A famous example is &lt;a href=&quot;https://en.wikipedia.org/wiki/Maitotoxin&quot; rel=&quot;nofollow noreferrer&quot;&gt;Maitotoxin&lt;/a&gt;, a small molecule that chemists have tried to synthesize for 22 years without success.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So perhaps there could be a particular organic compound that has been recycled and reused over time in the bodies of the plants and animals on the lunar colony, but over time that compound degrades (by cosmic rays, UV light, or whatever), so animals and/or plants start developing problems due to the lack of this compound that none of the organisms placeable in the colony are capable of synthesizing. Therefore, they need to go back to Earth to get it from some ocean-dwelling creature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Perhaps it would be something like a vitamin required by plants.  Or maybe a compound that could be needed to cure a disease.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-02T00:04:22.463" LastActivityDate="2018-03-02T00:04:22.463" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13473" PostTypeId="1" CreationDate="2018-02-27T00:27:03.420" Score="5" ViewCount="1047" Body="&lt;p&gt;I image most people have heard stories of fish, frogs, or other small animals raining from the sky.  I found quite a few articles on line with many instances of such occurrences but they were mostly from historic times and often from second or third person accounts.  Then I came across this article from &lt;a href=&quot;https://blog.nationalgeographic.org/2013/07/19/sharknado-got-one-thing-right-aquatic-animals-sometimes-do-fall-from-the-sky/&quot; rel=&quot;noreferrer&quot;&gt;National Geographic&lt;/a&gt; which mentions two more recent accounts.  The first they mention is a fish drizzle which occurred in Lajamanu, Australia in 2010 and the second is a frog fall which occurred in Odzaci, Serbia in 2005.  Both of these events seemed to be backed up by meteorological claims of either tornadoes in the Australia case or waterspouts in the Serbia case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I'm curious about is:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;If this is somewhat relatively common, with the abundance of video cameras&#xA;now, why hasn't something like this been recorded.  I've had no luck&#xA;finding anything on line.&lt;/li&gt;&#xA;&lt;li&gt;Why does it seem like it's always one type of animal?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2023-08-14T20:20:49.647" Title="Is there any video evidence of animals raining from the sky?" Tags="|meteorology|tornado|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13474" PostTypeId="5" CreationDate="2018-02-27T02:38:21.540" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2018-02-27T02:38:21.540" LastActivityDate="2018-02-27T02:38:21.540" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13475" PostTypeId="4" CreationDate="2018-02-27T02:38:21.540" Score="0" Body="Questions relating to natural events such as severe weather events or seismic events that can result in the loss of life and/or significant or large scale destruction of natural or human environments." OwnerUserId="12057" LastEditorUserId="2470" LastEditDate="2018-02-27T11:10:30.133" LastActivityDate="2018-02-27T11:10:30.133" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13476" PostTypeId="2" ParentId="13464" CreationDate="2018-02-27T03:21:02.983" Score="0" Body="&lt;p&gt;No, it is logarithmic. Each doubling of CO2 concentration will result in a constant increase in temperature which is called the equilibrium climate sensitivity, estimated to be 1.5C to 4.5C. &lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_sensitivity#Equilibrium_and_transient_climate_sensitivity&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2018-02-27T03:21:02.983" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13477" PostTypeId="1" CreationDate="2018-02-27T04:23:15.213" Score="3" ViewCount="110" Body="&lt;p&gt;Look at this amazing frost I woke up to in Sooke, BC, Canada. This was so very cool to wake up to.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SBJfQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SBJfQ.jpg&quot; alt=&quot;picture of frost&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12324" LastEditorUserId="28050" LastEditDate="2018-03-02T12:48:38.963" LastActivityDate="2018-03-02T12:48:38.963" Title="Can anyone explain this frost phenomenon?" Tags="|meteorology|ice|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13478" PostTypeId="1" CreationDate="2018-02-27T05:18:58.680" Score="3" ViewCount="93" Body="&lt;p&gt;I have a 150M deep borehole. We want to measure ground water level using a pressure sensor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I believe that it is best practice to make use of a &lt;code&gt;Piezometer tube&lt;/code&gt; before installing the actual sensor.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;This prevents the sensor from getting tangled with the pump&lt;/li&gt;&#xA;&lt;li&gt;Large pumps can create a vortex current which will cause the sensor to move round&lt;/li&gt;&#xA;&lt;li&gt;Also helps smooth out any irregularities in the water level.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I was wandering what is the best type of piping to use for this tube?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am biased towards using a pvc pipe as it does not have any radial bend and can therefore be inserted into the well much easier. However I would have to join many smaller segments together and I am concerned that these joins might come undone over time. Vertically hanging 150m of 30mm pvc will probably be quite heavy.&lt;/p&gt;&#xA;" OwnerUserId="12326" LastActivityDate="2018-02-27T05:18:58.680" Title="Best material for Piezometer tube in water well" Tags="|hydrology|groundwater|underground-water|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13479" PostTypeId="2" ParentId="13477" CreationDate="2018-02-27T06:25:39.947" Score="4" Body="&lt;p&gt;I am going to take a guess and say these are &lt;a href=&quot;http://www.its.caltech.edu/~atomic/snowcrystals/frost/frost.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Frost crystals&lt;/a&gt;. There are few conditions that need to be present in order for these to develop&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Light wind  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Relatively high humidity(some water vapor source perhaps nearby) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) Depending on your elevation - was this somewhere near a mountain basin ? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As opposed to snow crystals frost crystals form more near the surface&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can read this article  &lt;a href=&quot;https://avalanche.org/avalanche-encyclopedia/surface-hoar/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Frost crystal&lt;/a&gt; and if the answers are in the affirmative&#xA;then you know these are the conditions that caused these crystals to form.  &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2018-02-27T06:30:45.420" LastActivityDate="2018-02-27T06:30:45.420" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13481" PostTypeId="1" CreationDate="2018-02-27T12:34:02.943" Score="1" ViewCount="83" Body="&lt;p&gt;I'm calculating warming trends in specific places and periods of time, that are related to the time a migratory bird spends in a stopover. But using different methods I got different results and I'm trying to figure out which is the most accurate. I know it will depend on location, so my sites are Southeast Canada and the Arctic. How much warming is possible in 40 years for example in a period covering only one month in spring, like May? What would be a good value to compare my results? spring temperature warming trend?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's a lot of fluctuation in temperatures, so when averaging them I get no changes, including in the Arctic, which cannot be true. I looked at trends of the maximum temperatures and they are increasing, also investigated the anomalies, but I would like to have an advice.&lt;/p&gt;&#xA;" OwnerUserId="7256" LastEditorUserId="11908" LastEditDate="2019-03-11T21:10:30.923" LastActivityDate="2019-03-11T21:10:30.923" Title="How much warming there was over time for a specific month?" Tags="|climate-change|climate|temperature|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13483" PostTypeId="1" CreationDate="2018-02-27T15:40:28.433" Score="1" ViewCount="61" Body="&lt;p&gt;Air temperature is known to correlate well with precipitable water at higher latitudes. What are the likely factors that degrade the correlation in the tropical monsoon climate? &lt;/p&gt;&#xA;" OwnerUserId="12330" LastEditorDisplayName="user1066" LastEditDate="2018-02-28T13:39:10.830" LastActivityDate="2018-02-28T13:39:10.830" Title="Correlation between temperature and precipitable water in the tropical climate" Tags="|meteorology|climate-change|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13484" PostTypeId="1" AcceptedAnswerId="13499" CreationDate="2018-02-27T16:07:14.277" Score="4" ViewCount="3173" Body="&lt;p&gt;I am using the CAMS model output data to figure out the ground level ozone at a particular place. It is given in mass mixing ratio, and I want to convert to parts per billion volume mixing ratio (volume/volume).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5x0Mr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5x0Mr.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shown above are ozone values from a model – basically the given values on the right beside the dates are in $\mathrm{kg} \cdot \mathrm{kg}^{-1}$. How can I convert them to ppbV?&lt;/p&gt;&#xA;" OwnerUserId="12328" LastEditorUserId="94" LastEditDate="2018-02-28T06:59:07.967" LastActivityDate="2021-09-28T08:35:43.413" Title="How do I convert kg·kg⁻¹ to ppbV (parts per billion volume)?" Tags="|meteorology|atmosphere|ozone|gas|mathematics|" AnswerCount="3" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13486" PostTypeId="1" AcceptedAnswerId="13537" CreationDate="2018-02-27T17:00:25.833" Score="6" ViewCount="156" Body="&lt;p&gt;I'm working with  Ozone Monitoring Instrument (OMI) $\ce{NO_2}$ vertical column density (molecules/cm&lt;sup&gt;2&lt;/sup&gt;) data. To help interpret the values, I'm wondering if there are standards that show which values are considered low vs high, or good vs hazardous (similar to the air quality index/ AQI). Have any agencies (e.g., EPA, WHO, EU) published anything related to this? &lt;/p&gt;&#xA;" OwnerUserId="12333" LastEditorUserId="28050" LastEditDate="2018-03-02T13:18:28.833" LastActivityDate="2018-03-03T20:36:03.733" Title="Are there standards for tropospheric NO2 levels considered low or high?" Tags="|remote-sensing|air-pollution|" AnswerCount="1" CommentCount="3" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13487" PostTypeId="2" ParentId="13484" CreationDate="2018-02-27T17:16:18.267" Score="0" Body="&lt;p&gt;1 part per billion is 1x10^-9 kilograms per kilogram so to convert a kilogram per kilogram ratio into a parts per billion figure divide it by 1x10^-9.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-02-27T17:16:18.267" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13488" PostTypeId="2" ParentId="13481" CreationDate="2018-02-27T17:24:18.677" Score="1" Body="&lt;p&gt;It is hard  to help unless you clarify what methods have you tried. However, I would suggest to explore reanalysis weather models, as they are the most accurate source of estimated weather conditions worldwide in the past.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A recommended reanalysis is ERA-interim, starting in 1979 so it gives you  39 years, if you really need 40 you can use JRA-55 that starts on 1955.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://climexp.knmi.nl/selectfield_rea.cgi?id=someone@somewhere&quot; rel=&quot;nofollow noreferrer&quot;&gt;KNMI Climate Explorer&lt;/a&gt; is a great way to retrieve and plot data from those models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you get in there you can set it to plot monthly mean temperatures for a given location. Here is an example of somewhere in SW Canada:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Q80GW.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Q80GW.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That will produce a plot like this:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/gUxP4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gUxP4.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Were you can click the &quot;raw data&quot; to get the raw values, and that will produce an output like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cW4VZ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cW4VZ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where each row is a year and each column is a month. So you can pick the column of the month of your interest and compute the trend from that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does it makes sense?&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-02-27T17:33:59.707" LastActivityDate="2018-02-27T17:33:59.707" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13489" PostTypeId="2" ParentId="13442" CreationDate="2018-02-27T20:12:46.053" Score="5" Body="&lt;p&gt;Examining two extreme cases, one very cold and the other very warm, the amount of precipitable water in the very cold one will be far less than that in the very warm one.  Even fully saturated, the very cold air mass would need to be lifted quite high to form large enough ice crystals or water droplets to have enough mass to begin falling.  Meanwhile, the warm air mass would produce larger droplets very quickly.  Thus the warm air mass would begin to produce precipitation at a lower altitude, and with greater intensity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because the air masses begin precipitating at different altitudes, the point of maximum intensity would also be lower for the warm air mass.&lt;/p&gt;&#xA;" OwnerUserId="12334" LastActivityDate="2018-02-27T20:12:46.053" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13492" PostTypeId="5" CreationDate="2018-02-28T04:15:33.463" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2018-02-28T04:15:33.463" LastActivityDate="2018-02-28T04:15:33.463" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13493" PostTypeId="4" CreationDate="2018-02-28T04:15:33.463" Score="0" Body="Questions related to orographic impact on fluid flows in the atmosphere" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2018-02-28T10:55:40.573" LastActivityDate="2018-02-28T10:55:40.573" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13495" PostTypeId="1" CreationDate="2018-02-28T09:08:09.047" Score="9" ViewCount="900" Body="&lt;p&gt;This is a rather general question: assume I have a system that has a certain 'forgetful' property, which means that while I can offset its current state for a moment, it will eventually return to its undisturbed state. An example would be a length of river (say, 100 m) from which I extract a certain amount of water: two days later it would not matter if I had removed the water or not. The system would not show any traces of my previous actions.&#xA;The opposite case would be a rock, a chunk of which I chisel away. Two days later the gap would still remain; the 'system' would never return to its original state.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would you call a system that displays such 'forgetfulness'?&lt;/p&gt;&#xA;" OwnerUserId="12339" LastEditorUserId="94" LastEditDate="2018-02-28T12:50:56.113" LastActivityDate="2018-03-05T14:35:31.263" Title="Correct phrase for a 'forgetful' natural system?" Tags="|hydrology|models|terminology|" AnswerCount="5" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13496" PostTypeId="2" ParentId="13495" CreationDate="2018-02-28T11:07:04.033" Score="4" Body="&lt;p&gt;Terms that come to mind are self or continuously or automatically:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;restoring&lt;/li&gt;&#xA;&lt;li&gt;replenishing&lt;/li&gt;&#xA;&lt;li&gt;renewing&lt;/li&gt;&#xA;&lt;li&gt;regenerating&lt;/li&gt;&#xA;&lt;li&gt;repairing&lt;/li&gt;&#xA;&lt;li&gt;healing&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-02-28T11:07:04.033" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13497" PostTypeId="2" ParentId="13495" CreationDate="2018-02-28T11:19:54.880" Score="6" Body="&lt;p&gt;From physics standpoint I would say that such system is &lt;strong&gt;stable&lt;/strong&gt;. For example think of a ball on a surface. If the ball is initially on the top of a hill a push would move the ball into the slope that would only accelerate it further from the original location/state (unstable system). If the ball is instead initially in a pit or local minimum, any push would move the ball to the slope only to turn back towards its original location (stable system).&lt;/p&gt;&#xA;" OwnerUserId="6465" LastEditorUserId="6465" LastEditDate="2018-02-28T15:16:55.887" LastActivityDate="2018-02-28T15:16:55.887" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13498" PostTypeId="2" ParentId="13495" CreationDate="2018-02-28T11:45:07.517" Score="7" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;How would you call a system that displays such 'forgetfulness'?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In one word, dissipative. In multiple words, a system whose autocorrelation function tends to zero as time tends to infinity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that the autocorrelation function may not exist; this concept implicitly assumes a linear (or approximately linear) system. Consider a river. Adding a small impulse of water upstream (e.g., a not-too-large downburst) results in the river flow increasing briefly but eventually stabilizing to some nominal value. Adding a slightly larger impulse results in a similar but slightly larger response. But adding a huge impulse of water upstream (e.g., a very large and rapid snowmelt) may cause the river to carve itself a new channel. With this huge impulse, the flow at some downstream point will increase initially but then drop to zero and stay that way because the river no longer flows past that point.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-02-28T11:45:07.517" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13499" PostTypeId="2" ParentId="13484" CreationDate="2018-02-28T13:19:04.267" Score="7" Body="&lt;p&gt;So if you have a mass-mixing ratio, you effectively $\frac{ \text{kg pollutant}}{\text{kg dry air}}$. PPBV is parts per billion volume, or number of molecules of pollutant per billion molecules of dry air. Since not all particles weigh the same, you must use a conversion factor. Consider molar mass, which is the ratio of moles (a unit describing the number of molecules/photons/atoms) to mass. Ozone has a molar mass of 48 kg mol$^{-1}$. Dry air doesn't have a molar mass per se, but an effective molar mass may be computed by a weighted sum of the molar masses of the consitituent chemicals (or you can Google it). Afterwards, you may have to multiply by a billion.$$\therefore \frac{ \text{kg pollutant}}{\text{kg dry air}} \times\frac{\frac{\text{mols of pollutant}}{\text{kg of pollutant}}}{\frac{\text{mols of dry air}}{\text{kg of dry air}}}=\frac{\text{mols of pollutant}}{\text{mols of dry air}}$$&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2018-02-28T13:19:04.267" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13500" PostTypeId="2" ParentId="13495" CreationDate="2018-02-28T14:41:52.167" Score="3" Body="&lt;p&gt;In biology this would be a form of Homeostasis, a tendency to a particular optimum state.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That could apply to your case too I think.&lt;/p&gt;&#xA;" OwnerUserId="12341" LastActivityDate="2018-02-28T14:41:52.167" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13501" PostTypeId="1" CreationDate="2018-02-28T18:39:59.683" Score="9" ViewCount="230" Body="&lt;p&gt;Currently central and northern Europe are experiencing a very cold, false-spring like weather phenomenon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When i look at local weather charts, the daily temperature cycle seems to be completely gone, and replaced by a constant -8°C to -10°C, see below for an example of southern Sweden. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/coxtA.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/coxtA.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Taking a look at ventusky.com we also see that the cold air is being advected from colder regions in Europe to southern Sweden, as seen in this screencap:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4twcg.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4twcg.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other locations don't display this behaviour any more:&#xA;The farther south I look, i.e. Berlin and Munich, the stronger the daily fluctuations get again, see both for comparison:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FOODz.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FOODz.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/v4fog.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/v4fog.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This 'constant temperature' seems odd enough for me to ask the question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is the constant temperature here in southern Sweden for a few days a lucky coincidence of temperature advection sources, or is this a known phenomenon and there is some interesting physics behind this?&lt;/strong&gt; &lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="111" LastEditDate="2018-03-07T15:41:39.657" LastActivityDate="2018-03-07T15:41:39.657" Title="Where did the daily temperature variation go?" Tags="|meteorology|temperature|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13502" PostTypeId="1" CreationDate="2018-02-28T18:47:37.927" Score="5" ViewCount="228" Body="&lt;p&gt;As a (smaller) part of my research, I want to look at climate projection data and how that might influence the hydrology within a study catchment in Rajasthan, India. For &quot;the present day&quot; climate, I run a simple soil moisture model that gives an estimate of the groundwater recharge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I aquired MPI-ESM data for the pathways RCP4.5 and RCP8.5 downscaled as part of the CORDEX project for the years 2006-2100. The annual means (or sums, in case of precipitation) are shown below for r1i1p1.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NM1HE.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NM1HE.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;However, the mean annual observational values for the last few decades are:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;variable,               value&#xA;u2_m_per_s              2.28&#xA;rh_mean                 46.88&#xA;actual_sunshine_hrs_day 7.17&#xA;tmean_degree            25.05&#xA;precipitation_mm        568&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Some of the variables, such as windspeed, are not yet adjusted to the same reference height, however the most striking deviation is the predicted precipitation, which even for the &quot;present&quot; is far off.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What simple possibilities are there to transform the RCP data to &quot;fit&quot; the observational data in the beginning of the projections? As mentioned, this is a side part and there are no resources for an elaborate approach.&#xA;Would it be possible to normalize the RCP timeseries with its own &quot;beginning&quot;, say the mean of the variables of the first twenty years, and then multiply it with the observational values above? That way I would get move the beginning of the time series closer to the observations while still maintaining the (relative) trend in the data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Normalized to the mean 2006-2020 values:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dYyG8.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dYyG8.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rescaled with the observational data:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZzOTh.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZzOTh.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How would one then continue? I'm aware that the signal is only within the trend, so would I look at two years, e.g. 2050 and 2080, that both are represented as the mean values of the year +- 15 years, similar to the data provided by WorldClim? Also, would I calculate the means time-step wise? &lt;/p&gt;&#xA;" OwnerUserId="11466" LastActivityDate="2018-02-28T18:47:37.927" Title="How to relate RCM/GCM RCP climate projections to observational data for use in a hydrologic model" Tags="|climate-change|hydrology|climate-models|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13503" PostTypeId="2" ParentId="13454" CreationDate="2018-02-28T22:31:52.983" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Which Earth minerals would Moon colonists miss the most?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;tl;dr &lt;strong&gt;All of them.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As mentioned in the other answers here, it's about economics. Extracting an element from a mineral requires energy, chemical processes, equipment, waste management, etc. This has to be done per amount of rock. The more of the element in interest you have in your rock, the more economic it is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth has active geology: hydrothermal processes, plate tectonics, magmatism, surface erosion and weathering. The combination of that causes some element to be concentrated in ore deposits, where the enrichment factor over the average composition can get to several orders of magnitude. That's why we mine gold from lodes and not from your average soil or rock. This is why we mine iron from &lt;a href=&quot;https://en.wikipedia.org/wiki/Banded_iron_formation&quot; rel=&quot;nofollow noreferrer&quot;&gt;BIFs&lt;/a&gt; and not from sea sand.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;None of this happens on the moon. Very few elements are enriched to economic concentrations, maybe some copper and zinc close to ancient volcanic vents. But then, you need to dig the stuff. You need to chemically extract it. You need to do something with the mining waste.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most likely, you will need more of an element than you can extract. To break some rocks you will need some vanadium or titanium tools, or maybe tungsten carbide. There is wear and tear on the tools. You will need to make new tools. For that you will need to get even more vanadium and tungsten, that are simply not available. Maybe extraction processes require organic compounds. There are no suitable organic compounds on the moon. You will end up having to ship the stuff from Earth just to be able to support a mining operating, that will not produce enough materials to support the mining operation. This would be like dumping money in the rubbish bin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;So, no. Do not do it&lt;/strong&gt;. Mining on the moon will not be a self sufficient operation.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-02-28T22:31:52.983" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13504" PostTypeId="2" ParentId="13454" CreationDate="2018-03-01T06:03:43.213" Score="2" Body="&lt;p&gt;biologically produced ones like coal and other petrochemicals.  Marble, limestone, Diatomaceous earth, and other such minerals are candidates as well. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Manganese oxides may be a good candidate the biologically formed ones have several unique industrial applications due to having an unusual &lt;a href=&quot;https://www.whoi.edu/oceanus/feature/minerals-made-by-microbes&quot; rel=&quot;nofollow noreferrer&quot;&gt;microstructure&lt;/a&gt;. It is also most easily mined from seafloor sediment. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2018-03-01T06:03:43.213" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13505" PostTypeId="2" ParentId="13454" CreationDate="2018-03-01T13:02:42.147" Score="3" Body="&lt;p&gt;Feels like a space-ex question and I think a fair bit is likely to be missed in my post, but it's a fun question, so:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The biggest problem with the Moon is no atmosphere.   Other problems are no protection from UV light, protection from cosmic rays and very fine, small and jagged lunar dust.   Annoying stuff, gets into everything.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Getting stuff from Earth to the Moon is hugely energy intensive and expensive, so as much as possible, whatever could be obtained from the Moon, would be and as little as possible would be flown from Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basics like water, air to breath, vacuum sealed living spaces so they wouldn't need to wear pressure suits all the time, soil to grow food and machinery to build stuff (there's no point of just living on the Moon, it should be used for mining and building stuff).   Some manufacturing would be easier in the low gravity situation of the Moon, and unlike the Earth, where a space elevator is enormously hard to build, a space elevator could be built from the Moon for easy and cheap launches.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would think that the energy problem on the moon would be solvable, presumably by solar panels.   Perhaps by nuclear, though that takes a lot of equipment.   Solar might be easier to mass-manufacture.   Then you'd need batteries, which are heavy.  All that would probably be built on the Moon which would take time, but cheaper than sending material from Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some items they might be short on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Nitrogen.   Nitrogen is useful for fertilizer and it's useful to breathing.   Breathing pure oxygen is unhealthy (or so I've heard).   It may also be useful for some kinds of rocket fuel (I think I read that somewhere).   There's not much nitrogen on the moon.  (Mars has the same problem).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) hydrocarbons.   The Moon is dusty - really fine teeny tiny very annoying dust particles that get into everything.   Oil keeps stuff lubricated and oil makes a good sealant.   When (if) a colony is set up on the moon, they're going to want oil for a lubricant, and they'll want to manufacture rubber.   There's no oil deposits below the surface of the moon because there was never plant or sea life that got buried and turned into oil or coal over time.   There's very little carbon on the moon, no CO2, very little carbonate rock (er, I think).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think, those are the big two, Carbon and Nitrogen.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) Lithium.   This one I'm torn on.   Used for batteries, it's lower weight than Lead-acid batteries, but the low gravity of the Moon, lead-acid might not be a problem.   You can't burn fuel without oxygen in the atmosphere, so that leaves batteries or nuclear powered equipment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;4) Water, and I know that there's a report that there's a billion tons of water on the Moon and that may be true, but it's underground.  There's only a little water on the surface in craters that's easy to access.   Water would be a valuable resource on the Moon, not to be taken lightly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's probably a dozen others that I'm not smart enough to know about and there's plenty of Carbon and nitrogen and water on comets and asteroids, (especially comets), so, it's not an unworkable problem.   Capturing a small comet, harvesting it, while keeping it shaded from the sun, changing it's orbit - not easy.    All the ins and outs of space colonization make my head hurt.  It won't be easy.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="725" LastEditDate="2018-03-02T08:54:52.850" LastActivityDate="2018-03-02T08:54:52.850" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13507" PostTypeId="1" CreationDate="2018-03-01T16:12:16.103" Score="2" ViewCount="573" Body="&lt;p&gt;Currently there is a snow storm coming from Europe over the UK. This is drastically dropping the temperature and making it snow lots.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the snow coming from moisture that has been brought over from Europe (as part of the storm), or is it coming from moisture that was already in the atmosphere above the UK?&lt;/p&gt;&#xA;" OwnerUserId="12348" LastEditorUserId="94" LastEditDate="2018-03-02T07:17:49.873" LastActivityDate="2018-05-02T21:30:47.003" Title="Does the snow come from local moisture or transported moisture?" Tags="|meteorology|atmosphere|precipitation|snow|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13509" PostTypeId="1" AcceptedAnswerId="13541" CreationDate="2018-03-01T20:44:27.980" Score="8" ViewCount="11821" Body="&lt;p&gt;A nice picture for &quot;how mountains formed&quot; on Earth is due to the motion of tectonic plates. As the plates crash together, mountains may get &quot;pushed upwards&quot;. However, a quick look at a map of the tectonic plates on Earth will show that there are some clear examples of significant mountain ranges which do not lie along the tectonic plates. I noticed the Ural mountains first, but even the Appalachian mountains don't appear to be associated with a particular pair of tectonic plates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nevertheless, Wikipedia tells me that the Ural mountains formed by the collision of the Laraussa and Kazakhstania continents - so why is there not a plate boundary underneath the Ural mountains?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: Here are few links with tectonic plate maps, demonstrating that there is no known division between plates at the location of the Ural mountains. Of course, I can't independently verify these, I'm just relying on consistency of unknown sources.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.thoughtco.com/map-of-tectonic-plates-and-their-boundaries-1441098&quot; rel=&quot;noreferrer&quot;&gt;https://www.thoughtco.com/map-of-tectonic-plates-and-their-boundaries-1441098&lt;/a&gt;&#xA;&lt;a href=&quot;https://pubs.usgs.gov/gip/99/pdf/gip99_ppt.pdf&quot; rel=&quot;noreferrer&quot;&gt;https://pubs.usgs.gov/gip/99/pdf/gip99_ppt.pdf&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.learner.org/interactives/dynamicearth/tectonicsmap/&quot; rel=&quot;noreferrer&quot;&gt;https://www.learner.org/interactives/dynamicearth/tectonicsmap/&lt;/a&gt;&#xA;&lt;a href=&quot;https://earthobservatory.nasa.gov/Features/Tectonics/&quot; rel=&quot;noreferrer&quot;&gt;https://earthobservatory.nasa.gov/Features/Tectonics/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12351" LastEditorUserId="11908" LastEditDate="2019-03-04T00:35:07.067" LastActivityDate="2020-09-26T20:27:41.010" Title="How did the Ural mountains form?" Tags="|geophysics|plate-tectonics|geography|mountains|geomorphology|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13510" PostTypeId="1" AcceptedAnswerId="13515" CreationDate="2018-03-01T21:12:26.990" Score="1" ViewCount="503" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Judge_C._R._Magney_State_Park&quot; rel=&quot;nofollow noreferrer&quot;&gt;Devil's Kettle&lt;/a&gt; is a &lt;a href=&quot;https://en.wikipedia.org/wiki/Giant%27s_kettle&quot; rel=&quot;nofollow noreferrer&quot;&gt;pothole&lt;/a&gt; in the rock where a small river disappears underground in the Judge C.R. Magney State Park in Minnesota. Would it be possible to trace the path of the drainage conduit by throwing in a small waterproof GPS tracker?&lt;/p&gt;&#xA;" OwnerUserId="12151" LastEditorUserId="6031" LastEditDate="2019-04-05T03:14:30.977" LastActivityDate="2019-04-05T03:14:30.977" Title="Can a microGPS tracker trace the path of an underwater drainage conduit?" Tags="|water|groundwater|gnss|gps|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="13511" PostTypeId="1" CreationDate="2018-03-01T21:43:22.543" Score="5" ViewCount="1833" Body="&lt;p&gt;I keep reviewing this table to compare and contrast my results:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0FUog.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0FUog.jpg&quot; alt=&quot;chart of humidity vs temperature&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The parcel of air is at 35°C and a relative humidity of 43%.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I used &lt;a href=&quot;https://www.lenntech.com/calculators/humidity/relative-humidity.htm&quot; rel=&quot;noreferrer&quot;&gt;this online calculator&lt;/a&gt; and it stated that with these two factors it would be 16.01 g/kg. Is this correct? What is the formula for this answer?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If that is right how would one use that information in order to find the specific humidity? If the atmospheric pressure is at 1000 mb, what would its mixing ratio be?&lt;/p&gt;&#xA;" OwnerUserId="12218" LastEditorUserId="28050" LastEditDate="2018-03-02T13:13:01.137" LastActivityDate="2018-03-08T17:34:40.157" Title="How would I use data to find specific humidity and mixing ratio?" Tags="|meteorology|temperature|humidity|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13513" PostTypeId="1" AcceptedAnswerId="13520" CreationDate="2018-03-01T22:26:11.387" Score="2" ViewCount="396" Body="&lt;p&gt;Could not find these in my book but I found something I think might them online (is this correct):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Net radiation balance:&#xA;R_NET = SW↓ - SW↑ + LW↓ - LW↑&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Complete energy balance:&#xA;R_NET  - G = H  + LE&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Were H and LE are sensible and latent heat fluxes, and G is the ground heat flux.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are these right?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please help&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="12218" LastEditorUserId="11908" LastEditDate="2018-03-02T17:36:36.203" LastActivityDate="2018-03-02T17:36:36.203" Title="Are these the net radiation at surface, and the complete energy balance at surface?" Tags="|climate-change|geography|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13515" PostTypeId="2" ParentId="13510" CreationDate="2018-03-02T00:40:42.200" Score="7" Body="&lt;p&gt;GPS units require a clear view of the sky to fix their position. Because unlike radio signals used for communications, once the GPS signal have bounced in a wall becomes useless for computing the receiver's position. Therefore, the GPS would loss fix shortly after entering the pothole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://www.dnr.state.mn.us/mcvmagazine/issues/2017/mar-apr/devils-kettle-mystery.html&quot; rel=&quot;noreferrer&quot;&gt;studies made in the area that determined the point at which the water reenters the river&lt;/a&gt;, claim that the flow of water keep objects at the bottom of the pothole, explaining why they never resurface. So there is a high chance that you wouldn't see your GPS ever again.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, if your GPS were to resurface, it would fix its position again soon after regaining a clear view of the sky. So, if you recover it (or if it had the capability to transmit its position in real time), you won't see a record of the track followed by the device, you would see only the entry and exit point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For such problems, similar to a car going trough a tunnel, the GPS is usually augmented with &lt;a href=&quot;https://en.wikipedia.org/wiki/Inertial_navigation_system&quot; rel=&quot;noreferrer&quot;&gt;inertial navigation systems&lt;/a&gt; that can estimate the displacements and compute the position by &lt;a href=&quot;https://en.wikipedia.org/wiki/Dead_reckoning&quot; rel=&quot;noreferrer&quot;&gt;dead reckoning&lt;/a&gt; from the last GPS fix. Despite that the turbulence within the water flow in the pothole would make very challenging to keep track of the trajectory of the device underground, a sophisticated enough device should be able to do it.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-03-02T00:40:42.200" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13516" PostTypeId="2" ParentId="13507" CreationDate="2018-03-02T00:54:09.770" Score="1" Body="&lt;h1&gt;It comes from nearby bodies of water, such as the ocean.&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Precipitation of any kind (in this case snow) comes from water that is evaporated from bodies of water like lakes or oceans nearby due to heat (usually not far from where it's going to precipitate). The evaporation forms clouds, which move a certain distance (depending on the cloud, cloud type, and atmosphere temperature and/or conditions) across the globe. Eventually, the vapor in the clouds condenses into rain after cooling enough to do so; thus, creating precipitation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xsqp0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xsqp0.jpg&quot; alt=&quot;water cycle&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Even though only half of the water cycle is explained in my first paragraph, the other half is not needed to answer the question. If you wish to learn more about the water cycle, please visit &lt;a href=&quot;https://www.rookieparenting.com/what-is-water-cycle/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this link&lt;/a&gt;.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to answer your question, a little bit of precipitation is from the atmosphere, but most of it is from water that has been evaporated from bodies of water nearby. And in the scenario you've mentioned, the moisture most likely came from the &lt;a href=&quot;https://www.google.com/search?q=atlantic+ocean&amp;amp;rlz=1CALEAL_enUS782US782&amp;amp;oq=atlantic+oc&amp;amp;aqs=chrome.1.69i57j0l5.10737j1j7&amp;amp;sourceid=chrome&amp;amp;ie=UTF-8&amp;amp;safe=active&amp;amp;ssui=on&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atlantic Ocean&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;So the real answer is kinda both :/&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The moisture comes from nearby water bodies, and then it's transported to where it's going to precipitate. It is local and transported moisture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Sources:&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://worldbuilding.stackexchange.com/questions/61774/how-far-will-rain-clouds-travel-inland&quot;&gt;Worldbuilding SE&lt;/a&gt; &lt;em&gt;(convenient)&lt;/em&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.rookieparenting.com/what-is-water-cycle/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rookie Parenting Science&lt;/a&gt; &lt;em&gt;(same link as shown in second paragraph)&lt;/em&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.google.com/search?q=atlantic+ocean&amp;amp;rlz=1CALEAL_enUS782US782&amp;amp;oq=atlantic+oc&amp;amp;aqs=chrome.1.69i57j0l5.10737j1j7&amp;amp;sourceid=chrome&amp;amp;ie=UTF-8&amp;amp;safe=active&amp;amp;ssui=on&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google search for Atlantic Ocean&lt;/a&gt; &lt;em&gt;(and I guess all the links on that google search too)&lt;/em&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="12057" LastEditorUserId="12057" LastEditDate="2018-03-03T15:27:07.740" LastActivityDate="2018-03-03T15:27:07.740" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13517" PostTypeId="1" AcceptedAnswerId="13518" CreationDate="2018-03-02T01:03:38.817" Score="6" ViewCount="1138" Body="&lt;p&gt;In meteorology the seasons always start at the beginning of the month the astronomical seasons start.&lt;br&gt;&#xA;The astronomical seasons start around the 21st in a month so I guess it would make more sense to start the meteorological season at the first day of the month following the start of the astronomical season.&lt;br&gt;&#xA;Another more logical reason to do this: for example the meteorological winter start at December 1 and ends at February 28 (or 29) in the next year so meteorology actually measures in broken years. Should the meteorological winter start at January 1 and end at March 31 then all seasons do exactly fit in the same year.&lt;br&gt;&#xA;So is there a reason why meteorologists do it this way or is it just arbitrarily chosen?&lt;/p&gt;&#xA;" OwnerUserId="12353" LastActivityDate="2018-09-21T15:21:08.970" Title="Why do meteorological seasons start earlier than astronomical seasons?" Tags="|meteorology|seasons|astronomy|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13518" PostTypeId="2" ParentId="13517" CreationDate="2018-03-02T01:14:14.903" Score="11" Body="&lt;p&gt;Meteorological seasons are based on temperature, whereas astronomical seasons are based on the position of the earth in relation to the sun.  So meteorological winter is the three coldest months of the year (December, January, and February) and meteorological summer is the three warmest months of the year (June, July, and August).  More information can be found on this &lt;a href=&quot;https://www.ncei.noaa.gov/news/meteorological-versus-astronomical-seasons&quot; rel=&quot;noreferrer&quot;&gt;NOAA web site&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastEditorDisplayName="user11318" LastEditDate="2018-03-02T01:19:33.397" LastActivityDate="2018-03-02T01:19:33.397" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13519" PostTypeId="2" ParentId="13517" CreationDate="2018-03-02T11:09:04.920" Score="3" Body="&lt;p&gt;As JeopardyTempest commented: Actually, the astronomical seasons are defined in such a way that you should expect them to be a full 1 ½ months behind, not just 21 days! Namely, astronomical winter only &lt;em&gt;starts&lt;/em&gt; at the winter solstice, astronomical spring only &lt;em&gt;starts&lt;/em&gt; at the equinox etc.. A more intuitive definition would arguably be if the seasons were &lt;em&gt;centered&lt;/em&gt; around these events. I.e., the astronomical seasons have ⅛ year lag built in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This intrinsic misalignment is partially cancelled by another delay, the &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4505/why-is-march-colder-than-september-in-northern-hemisphere&quot;&gt;seasonal lag&lt;/a&gt;, which is in most places about a month. I.e. the temperature-defined meteorological seasons also lag behind the Earth's orbit, but by less than the astronomical seasons; the observation that the astronomical seasons lag behind the meteorological seasons by 21 days is just an alternative view point.&lt;/p&gt;&#xA;" OwnerUserId="12095" LastActivityDate="2018-03-02T11:09:04.920" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13520" PostTypeId="2" ParentId="13513" CreationDate="2018-03-02T12:56:04.760" Score="3" Body="&lt;p&gt;Yes, these are the correct terms.  The first equation is generally termed the 'surface radiation budget' and the second the 'surface energy budget'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As @Deditos pointed out, additional terms for biological storage and flux can be added and are in fact important sources when considering a microclimate, and these would generally be placed into the surface energy budget.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another form of the first equation is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rn = ϵLW↓ − σϵT_s^4 + (1−α)SW↓&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where ϵ is the longwave emissivity of the surface, σ is the Stephan-Boltzman constant, T_s is the surface temperature, and α is the albedo (see &lt;a href=&quot;http://www.mdpi.com/2225-1154/2/2/103/htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Huber et al.&lt;/a&gt;, section 3.2).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In certain circumstances, it is useful to set them equal to each other by solving for Rn, so you may also see&lt;/p&gt;&#xA;&#xA;&lt;p&gt;ϵLW↓ − σϵT_s^4 + (1−α)SW↓ = G + H + LE + (S + B)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where B is the biological flux.&lt;/p&gt;&#xA;" OwnerUserId="12334" LastEditorUserId="12334" LastEditDate="2018-03-02T13:39:39.530" LastActivityDate="2018-03-02T13:39:39.530" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13522" PostTypeId="1" AcceptedAnswerId="13532" CreationDate="2018-03-02T21:38:23.227" Score="10" ViewCount="1027" Body="&lt;p&gt;This question did arise when thinking on offshore solar power plants, what's their potential, and how efficient would they be compared with land based counterparts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recently, it is becoming more common to hear about offshore floating power plants, like &lt;a href=&quot;https://www.imarest.org/themarineprofessional/item/4042-dutch-consortium-to-build-world-s-first-offshore-solar-farm&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one&lt;/a&gt;, &lt;a href=&quot;https://www.dailysabah.com/istanbul/2017/08/04/turkeys-first-floating-solar-power-plant-built-in-istanbul&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one&lt;/a&gt; or &lt;a href=&quot;https://spectrum.ieee.org/energywise/energy/renewables/japan-building-worlds-largest-floating-solar-power-plant&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But when it comes to big projects, usually solar power plants are planned in very sunny places, like the Arizona desert to maximize output the power.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And when looking for the sunniest places on Earth, all the lists and ranks I've found only include land areas. All the above had motivated the following related questions:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Is it true that no place in the surface of oceans gets as much solar energy as a sunny place on land?&lt;/li&gt;&#xA;&lt;li&gt;Are the oceans always cloudy? Or cloudier than land?&lt;/li&gt;&#xA;&lt;li&gt;How much of the solar energy reaching Earth's surface fall on land and how much on the oceans?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="12251" LastEditorUserId="11908" LastEditDate="2019-03-04T00:33:49.073" LastActivityDate="2019-03-04T00:33:49.073" Title="What are the sunniest places on Earth? (including oceans)" Tags="|meteorology|oceanography|geography|sun|solar-terrestrial-physics|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13523" PostTypeId="2" ParentId="13522" CreationDate="2018-03-03T02:31:16.717" Score="4" Body="&lt;p&gt;1) No, there are many places in the ocean that receive &lt;em&gt;more&lt;/em&gt; sunlight hours than many deserts.  For instance, the west coasts of southern Africa and central South America.  These locations are influenced by the very cold antarctic currents and high pressure from Hadley cells.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) That very much depends on location.  In general, a warm ocean will be cloudier than a cold one.  The equatorial waters are particularly cloudy, while subtropical waters are generally less cloudy.  Meanwhile, some land areas are very cloudy much of the year.  For instance, Washington state is cloudy more often than not.  Mountainous regions are also often cloudy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3)  Most of the incoming reaching the Earth's surface falls on the oceans.  That is mostly due to the surface area of the oceans (~2/3 of the Earth).&lt;/p&gt;&#xA;" OwnerUserId="12334" LastEditorUserId="12334" LastEditDate="2018-03-05T23:14:20.767" LastActivityDate="2018-03-05T23:14:20.767" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13524" PostTypeId="2" ParentId="13501" CreationDate="2018-03-03T02:52:30.067" Score="4" Body="&lt;p&gt;There are (at least) five factors at play here:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;the cold air advection from the north east has driven temperatures down&lt;/li&gt;&#xA;&lt;li&gt;the cloud cover traps longwave radiation sort of like a blanket, keeping the night time temperatures from dropping&lt;/li&gt;&#xA;&lt;li&gt;also, the cloud cover prevents solar radiation from reaching the surface and warming it&lt;/li&gt;&#xA;&lt;li&gt;the relative humidity is near 100%, indicating that the dew point is nearly the same as the air temperature.  Dew point serves as a minimum possible temperature, so this also prevents the air temperature from dropping&lt;/li&gt;&#xA;&lt;li&gt;precipitation traveling through the lower atmosphere will evaporate, having two effects: cooling the atmosphere and maintaining a high dew point&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;(5) is only really a factor during the day when temperatures would normally be on the rise.  The precipitation will keep the diurnal heating to a minimum.&lt;/p&gt;&#xA;" OwnerUserId="12334" LastEditorUserId="12334" LastEditDate="2018-03-06T13:01:51.860" LastActivityDate="2018-03-06T13:01:51.860" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13525" PostTypeId="1" AcceptedAnswerId="13526" CreationDate="2018-03-03T03:31:38.037" Score="4" ViewCount="215" Body="&lt;p&gt;When I dropped a stone or a crystal onto the floor, can it be considered as erosion? What is the difference between rocks breaking due to natural disturbances vs human action?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is the stone/crystal I dropped&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2yCZR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2yCZR.jpg&quot; alt=&quot;one angle&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/7SEFf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7SEFf.jpg&quot; alt=&quot;another angle&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/7mIt2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7mIt2.jpg&quot; alt=&quot;another angle&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12349" LastEditorUserId="12349" LastEditDate="2018-03-06T15:34:14.650" LastActivityDate="2018-03-06T15:34:14.650" Title="Confused about whether physical impact is 'erosion'" Tags="|terminology|human-influence|erosion|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13526" PostTypeId="2" ParentId="13525" CreationDate="2018-03-03T09:12:59.063" Score="7" Body="&lt;p&gt;I'm assuming here that you're asking whether you can apply the term ‘erosion’ to the damage your stone suffered, rather than the damage your floor suffered. In this case, the applicability of the term hinges not so much on &lt;em&gt;who's doing it&lt;/em&gt; as on &lt;em&gt;what it's happening to&lt;/em&gt;. In geology, the term ‘erosion’ is usually applied to land surfaces rather than individual, loose bits of rock. For instance, the &lt;em&gt;Oxford English Dictionary&lt;/em&gt; has:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;erode&lt;/strong&gt;, v.&lt;br&gt;&#xA;  2. Geol. Of the action of currents, glaciers, etc.:&lt;br&gt;&#xA;  a. To wear away; to eat out.&lt;br&gt;&#xA;  b. To form (a channel, etc.) by gradual wearing away.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Nichols (2009), more concisely, says&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... erosion is the removal of regolith material.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Once your stone is picked up and taken into your house, it's no longer part of the regolith material, although the surface you took it from was itself eroded by the stone's removal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the literature, human influences aren't usually excluded when discussing ‘erosion’. For example, the term is often applied when discussing how footpaths are worn down by human use (see e.g. Coleman, 1981).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, if your dropped stone chipped a bit out of your floor, you &lt;em&gt;might&lt;/em&gt; try to claim that as erosion, but only if you're prepared to argue that your floor constitutes regolith!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want a geologically appropriate term for what happened to your stone, &lt;em&gt;abrasion&lt;/em&gt; would probably cover it. Allaby (2008) has this definition:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;abrasion&lt;/strong&gt; (corrasion): The erosive action that occurs when rock particles of varying size are dragged over or hurled against a surface.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The use of ‘erosive’ in the definition perhaps doesn't make it entirely clear that this can apply to the particles as well as the surface itself, but it's easy to check that ‘abrasion’ is indeed used in this way in the literature. For example, again from Nichols (2009):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... sharp edges tend to be chipped off first, the abrasion smoothing the surface of the clast.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Responses to comments&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Does this mean that when my stone suffers abrasion, it is now destroyed?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No, not at all. ‘Abrasion’ just means that some material has been removed from your stone by mechanical action. Of course it would be possible to abrade your stone so much that it was completely destroyed, but this isn't implied by the term ‘abrasion’ itself.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What would happen to the damage over time? Will weathering try to repair it?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In general, material removed from a piece of rock will not be repaired by natural processes. In some natural environments, new minerals may precipitate in a crack left by abrasive damage, but this won't happen to a piece of rock sitting on a shelf in your house :). In the natural course of the rock cycle, an abraded fragment of rock may eventually be ‘recycled’ rather than being ‘repaired’ -- for example, it may be incorporated into a conglomerate, or buried, melted, and recrystallized as a new igneous rock.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Allaby, M. (2008). &lt;em&gt;Oxford Dictionary of Earth Science&lt;/em&gt;. Oxford University Press.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Coleman, R. (1981). Footpath erosion in the English Lake District. &lt;em&gt;Applied Geography&lt;/em&gt;, 1(2), 121-131.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nichols, G. (2009). &lt;em&gt;Sedimentology and stratigraphy&lt;/em&gt;. John Wiley &amp;amp; Sons.&lt;/p&gt;&#xA;" OwnerUserId="94" LastEditorUserId="94" LastEditDate="2018-03-05T21:39:25.133" LastActivityDate="2018-03-05T21:39:25.133" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13527" PostTypeId="1" CreationDate="2018-03-03T16:55:28.093" Score="2" ViewCount="1053" Body="&lt;p&gt;To me it seems that there is a lot less precipitation when temperatures go below -5°C (23°F).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any evidence for that? Could this be a local phenomenon (I live in Germany)? What could be the cause for this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried searching for charts that show precipitation over temperature, but all I could find were charts that showed precipitation over months of year which is not quite the same.&lt;/p&gt;&#xA;" OwnerUserId="12369" LastActivityDate="2018-03-21T19:28:45.420" Title="Is there less precipitation (rain/snow) in cold weather than in warm weather?" Tags="|temperature|precipitation|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13528" PostTypeId="1" AcceptedAnswerId="13535" CreationDate="2018-03-03T17:11:35.833" Score="0" ViewCount="178" Body="&lt;p&gt;How does radiation and shock waves from a radioactive asteroid or atomic explosion disperse throughout Earth's atmosphere?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there specific areas on Earth that are less likely to receive the shock wave or radiation by being on the other side of the Earth and/or land or wind characteristics like being in a deep valley? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm trying to go with the worst case survivable scenario if the asteroid hit with the possibility of hitting a nuclear reactor, arsenal or deposit of uranium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WDayO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WDayO.png&quot; alt=&quot;Image of mushroom cloud heights&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Related:&lt;/h3&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;This is from &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13453/safest-spots-when-an-asteroid-hits&quot;&gt;a broad question&lt;/a&gt; that I am breaking up in 3 questions. Feel free to edit.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Which of these scenarios would have a smaller chance of being struck?&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;In the air of some type blimp or aircraft on the opposite side of the Earth?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/13531/does-being-under-water-provide-any-protection-from-a-asteroid&quot;&gt;Does being under water provide any protection from a asteroid?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2018-03-07T22:57:42.093" LastActivityDate="2018-03-07T22:57:42.093" Title="Does being in the air provide any protection from an asteroid?" Tags="|meteorology|wind|meteorite|atmospheric-radiation|natural-disasters|" AnswerCount="1" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="13530" PostTypeId="1" AcceptedAnswerId="13533" CreationDate="2018-03-03T17:51:16.017" Score="-5" ViewCount="1168" Body="&lt;p&gt;Can an explosion be felt in the ground on the opposite side of the Earth like from an asteroid? Would planes in the air on that side of the Earth be able to survive?&#xA;Does the shock waive follow the ground or will the curvature of the Earth limit the shock wave? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pUm9y.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pUm9y.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Related:&lt;/h2&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;This is from &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13453/safest-spots-when-an-asteroid-hits&quot;&gt;a broad question&lt;/a&gt; that I am breaking up in 3 questions. Feel free to edit.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Scenario 2.&lt;/strong&gt; On or Underground in a cave?&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2018-03-20T21:53:25.103" LastActivityDate="2018-03-20T21:53:25.103" Title="Can a shock wave travel around the Earth's curvature?" Tags="|geology|geophysics|plate-tectonics|crust|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13531" PostTypeId="1" AcceptedAnswerId="13534" CreationDate="2018-03-03T18:01:38.213" Score="0" ViewCount="571" Body="&lt;p&gt;Does being under or on water provide any protection from an asteroid hitting the opposite side of the Earth over being in or on land or in air? Why? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Will the shock wave follow the curvature of the Earth through the oceans?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm trying to go with the worst case survivable scenario.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Related:&lt;/h2&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;This is from &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13453/safest-spots-when-an-asteroid-hits&quot;&gt;a broad question&lt;/a&gt; that I am breaking up in 3 questions. Feel free to edit.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Scenario 3.&lt;/strong&gt; In a submarine or capsule underwater?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/13528/how-is-radiation-dispersed-by-earths-atmosphere&quot;&gt;Does being in the air provide any protection from an asteroid?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2018-03-07T23:16:00.280" LastActivityDate="2024-03-28T04:52:26.463" Title="Does being under water provide any protection from a asteroid?" Tags="|ocean|oceanography|tectonics|natural-disasters|thermodynamics|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13532" PostTypeId="2" ParentId="13522" CreationDate="2018-03-03T18:49:58.397" Score="11" Body="&lt;p&gt;It is an interesting question, and despite that latitude is the main control of the amount of solar radiation that reaches the top of the atmosphere at a given location, the answer will be determined by how exactly weather patterns distribute across the different latitudes. Therefore, a solid answer will require to be supported in data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good dataset for this propose is the one at the &lt;a href=&quot;https://eosweb.larc.nasa.gov/cgi-bin/sse/sse.cgi?skip@larc.nasa.gov&quot; rel=&quot;noreferrer&quot;&gt;Surface meteorology and Solar Energy&lt;/a&gt;. I recently used it to answer a &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13446/where-is-the-calmest-place-on-earth/13450#13450&quot;&gt;somewhat similar question&lt;/a&gt;. In this case I'll use the &lt;a href=&quot;https://eosweb.larc.nasa.gov/sse/global/text/22yr_swv_dwn&quot; rel=&quot;noreferrer&quot;&gt;Insolation Incident On A Horizontal Surface&lt;/a&gt; dataset, that provides a 22-year average (July 1983 - June 2005) of solar insolation in kWh/m^2/day (kWh per square meter per day) derived  from satellite measurements, allowing worldwide coverage at 1° resolution (~110 km).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The dataset looks like this:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/1W5Eq.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1W5Eq.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where the numbers in the color scale on the left have to be interpreted as average kWh/m^2/day. We can see a clear latitudinal gradient were the equatorial latitudes receive much more energy than polar ones, however there are significant longitudinal variations due to the different climates that can be found at the same latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a first look, land areas doesn't seem to receive more energy. Land over the equator seem receive relatively less energy (due to cloud cover), and the deserts &quot;hot spots&quot; like Atacama and Sahara are quite far from the equator (~2000 km). In the other hand, there seem to be extensive equatorial waters that receive a lot of energy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The figure shows the maximum of the data set (6.98 kWh/m^2/day), giving to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Atacama_Desert&quot; rel=&quot;noreferrer&quot;&gt;Atacama desert&lt;/a&gt; in Chile the title of the area that receive more solar insolation on Earth. However, it is a fairly small area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following picture show the same dataset overlaid on top of a world map to make land areas highlight a bit more, and contours on the areas receiving more than 6 kWh/m^2/day&#xA;&lt;a href=&quot;https://i.stack.imgur.com/tyKnu.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tyKnu.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;It is clear here that despite that the Sahara and Atacama deserts are within the areas with more insolation, the vast majority of such areas lay over the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, in regard to your first question, I would say that despite the first place of the highest solar irradiation contest go to the Atacama desert, the rest of the podium belongs to the oceans. In fact if we look at the &quot;pixels&quot; of the dataset with values above 6.9 kWh/m^2/day, there is two in the Atacama desert and 16 in the Pacific ocean. So in general I would say that &lt;strong&gt;it is false to say that no place in the surface of oceans gets as much solar energy as a sunny place on land&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer the second question we can have a look at the dataset of the &lt;a href=&quot;https://eosweb.larc.nasa.gov/cgi-bin/sse/subset.cgi?email=skip@larc.nasa.gov&quot; rel=&quot;noreferrer&quot;&gt;Monthly Averaged Clear Sky Days&lt;/a&gt; (i.e.  cloud cover less than 10% over the same 22-year period), and it looks like this:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/r6q1M.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/r6q1M.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA; This time the color bar numbers have to be interpreted as average clear sky days per month. Here we can see that the high insolation in the Atacama desert is explained by a very large amount of clear sky days (17 per month) while in that sunny Pacific ocean spot there is at most 10 clear sky days in average. But wen it comes to the record of the most clear skies days, the winner is Antarctica, with large expanses with 20-22 clear sky days ion average. However, if there is several month without sunshine I don't know if it could be translated as the &quot;sunniest&quot; place.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, in regard to your seconds questions, I would say &lt;strong&gt;YES, oceans have in average a much more persistent cloud cover than land&lt;/strong&gt;. In fact, pretty much all the areas with more than 10 clear sky days per month in average are on land, and the vast majority in Antarctica.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, to answer your third question we have to separate the data of the first dataset (first figure) into land and sea. To do that, I've used the &lt;a href=&quot;https://www.ngdc.noaa.gov/mgg/global/global.html&quot; rel=&quot;noreferrer&quot;&gt;ETOPO1 Global Relief Model&lt;/a&gt;, saying that any place at an elevation of 0 meters or more would be land, and anything below zero is ocean. I've also transformed the data to an equal-area projection, to make the calculation easier, as in the original data a &quot;pixel&quot; near the poles was much smaller than one at the equator.&#xA;The land area insolation looks like this:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/TUZ6W.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TUZ6W.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;And the sea insolation like this:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/jrCji.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jrCji.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;And the mean total insolation received by land is 6.45e14 kWh/day or 645 PWh/day (peta watts per day), in contrast with 1,656 PWh/day by oceans. &lt;strong&gt;Therefore 72% of the energy end up in the oceans&lt;/strong&gt;.&#xA;The total is 2,301 PWh/day, which as a sanity check, we can see that it have the same order of magnitude than the total amount of energy hitting the top of the atmosphere, a value that we can easily calculate using the &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_constant&quot; rel=&quot;noreferrer&quot;&gt;solar constant&lt;/a&gt; and Earth's radius (24*1.362*pi*6378100^2 = 4.177e15 Wh/day= 4,177 PWh/day). These two totals don't match as expected because a significant fraction of the energy gets reflected (&lt;a href=&quot;https://en.wikipedia.org/wiki/Albedo#Terrestrial_albedo&quot; rel=&quot;noreferrer&quot;&gt;Earth's albedo is 0.3&lt;/a&gt;) or absorbed by the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To wrap up all this information in the context of your question. There is indeed a great potential for offshore solar power, that maybe we will tap into in the future. However, the transport of the energy could be now the main constraint. Making offshore project viable only in areas of high real state prices, making too expensive to build them on land, and therefore making the offshore alternative a sensible one. In those cases the location is mostly dictated by the location of the demand more than the location with higher solar irradiation. If I let the imagination loose, maybe those large high-irradiation zones in the Pacific could one day host floating industrial complexes, producing and using the power on the spot for manufacturing or other industrial processes. &lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-05T21:49:24.307" LastActivityDate="2018-03-05T21:49:24.307" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13533" PostTypeId="2" ParentId="13530" CreationDate="2018-03-03T20:08:20.293" Score="1" Body="&lt;p&gt;The processes are a mixture of interesting relationships. An asteroid hitting the other side of the planet that could cause such a shock would be massive in scope and would cause significant issues. As far as we known, geologists,etc, its not impossible, but very very unlikely unless we are looking at an extinction type vent. I would imagine any planes would fare well that are either in the direct patch of the asteroid or in the general vicinity of the impact. We are talking the impact equivalent of several nuclear bombs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, with seismological equipment (seismograph) we can with great clarity, monitor explosions, earthquakes, or impacts. Seismographs during WW2 and later where used to detect nuclear detonations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Due to the crustal composition, or earths composition the shock-wave would travel through the lithosphere (crust and upper mantle) and I would imagine would spread similar to that of earthquakes. Such as certain waves traveling through the crust that a berried by transitions between the layers and some will pass through the liquid layers of the planet. That whole thing is enough to give you a headache, fascinating non the less.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to learn more about asteroids, I would suggest starting with: &lt;a href=&quot;https://en.wikipedia.org/wiki/Meteor_Crater&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Meteor_Crater&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now it is specific to meteors and may not answer your specific question but it is an interesting read.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This information came from a geology student. This is my first post and I am just trying to follow the rules.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope that gave some insight!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oh as for a cave, it would depend where, but you definitely could in the right locality and it would be the last place Id want to be, at least during impact and initial effects following the impact. If you into mega nature processes, check out the lat 1800's eruption of Krakatau, its explosion is the largest record in the US and what hear as far as Australia. Or Columbia river flood basalt or the ignimbrite storm.&lt;/p&gt;&#xA;" OwnerUserId="12371" LastActivityDate="2018-03-03T20:08:20.293" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13534" PostTypeId="2" ParentId="13531" CreationDate="2018-03-03T20:14:25.887" Score="1" Body="&lt;p&gt;No. It depends on the severity. Water would be worse. If an asteroid hit in the ocean we would experience tsunamis the size we get from large magnitude earthquakes. The displacement of the water would be massive. It would also cause things like swimming pools sloshing around, common to the videos you see of hotels from the 2011 Japan earthquake. If it hit on the opposite side of the Earth, land would still be a better spot. Tsunamis can translate vast distances depending on the level of energy and surface deformation they create. Being in a submarine?  Again, no. A tsunamis can pass under boats. However, impact from an asteroid vs sea floor deformation from earthquakes are different functions. The submarine one, would require someone with a little more expertise.&lt;/p&gt;&#xA;" OwnerUserId="12371" LastEditorUserId="6298" LastEditDate="2018-03-07T19:23:46.207" LastActivityDate="2018-03-07T19:23:46.207" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13535" PostTypeId="2" ParentId="13528" CreationDate="2018-03-03T20:19:15.093" Score="2" Body="&lt;p&gt;To answer the radiation question, it is both absorbed and reflected into space. A lot of these processes are complex relations between atmosphere, magnetosphere, and solar radiation. Solar radiation does penetrate through as it drives everything we need or any creature needs to live, whether directly or indirectly. Aurora Borealis is caused by Solar radiation trapped in our atmosphere. This is why Ozone (O3) is so important as it does a massive support function of helping block those rays. Some of this radiation is reflected by the earth as thermal radiation. The magnetosphere also plays a role in capturing and diffusing such particles. A little more research may help, it is a very fascinating process. For more:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Aurora&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Aurora&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This was from courses in astronomy, hydrology, and my brain. Use wisely.&lt;/p&gt;&#xA;" OwnerUserId="12371" LastActivityDate="2018-03-03T20:19:15.093" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13536" PostTypeId="2" ParentId="13527" CreationDate="2018-03-03T20:24:06.883" Score="2" Body="&lt;p&gt;I am in the US, my guess would be related to the vapor capacity of warm air. Warmer air carries more moisture, when it is forced upwared in elevation the temperature drops allowing more moisture to precipitate out. This is even more noticeable if your in an orographic (moutaninous/Hilly) terrain. I am not familiar with the geology/geography of your area, however, I would like to vist some day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am sure there are more details to my answer, that I just am not &quot;advanced&quot; enough to know now. Here is a link to a PDF that has some explanations. If your not a technical person, dont let the math formulas scare you. There is other information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://web.sahra.arizona.edu/education2/fossww/PCL/WaterVapor.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://web.sahra.arizona.edu/education2/fossww/PCL/WaterVapor.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cheers!&lt;/p&gt;&#xA;" OwnerUserId="12371" LastActivityDate="2018-03-03T20:24:06.883" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13537" PostTypeId="2" ParentId="13486" CreationDate="2018-03-03T20:26:59.670" Score="2" Body="&lt;p&gt;The OMI tropospheric NO2 retrieval algorithm does not provide surface concentrations of NO2, but rather a column density.  So, it isn't appropriate to directly correspond those OMI retrievals to health standards that are based on ambient concentrations at the surface.  There have been many attempts to correlate surface concentrations of NO2 to tropospheric NO2, but the correlation is fair at best.  Furthermore, the tropospheric column inherently changes depending on elevation, since the amount of atmosphere in the tropospheric column decreases as the surface elevation increases.   There are also several assumptions that go into the retrieval that create a large amount of error (e.g. stratospheric column subtraction, &lt;em&gt;a priori&lt;/em&gt; profiles, surface albedo, etc.).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I discuss in &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9108/the-higher-value-range-for-the-same-satellite-product-no2-omi-temis?rq=1&quot;&gt;this post&lt;/a&gt;, it is possible to distinguish clean, polluted, and highly polluted tropospheric NO2 columns.  However, the exact thresholds are specific to location and sometimes season as well, since the retrieval algorithm responds differently depending on parameter assumptions.  In general, if you are seeing values over ~5x10^15 molec/cm^2, you can be sure there is real NO2 pollution.  Anything over 1x10^16 molec/cm^2 is highly polluted.   The higher the values are, the more confidence there is in the retrieval.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see the responses from the creators of OMI for similar questions &lt;a href=&quot;http://projects.knmi.nl/omi/news/temis/faq_nrt_trop_no2.html#smog-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Does the red colour signal smog at the surface?&lt;/strong&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;No, since OMI does not measure the concentration at the surface directly. Instead, OMI measures the total amount of nitrogen dioxide (NO2) in a column up to about 10 km.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;However, research has shown that high NO2 column amounts in OMI measurements (red colours) usually coincide with high concentration levels at the surface. This concentration is usually not as high that you can it moderate or heavy smog, but it does still indicates an elevated level of air pollution. The OMI measurements clearly show that The Netherlands suffers from a significantly higher level of air pollution by NO2. See also the answers to the next questions.  Note that smog does not exist only of NO2. Other important ingredients are aerosols, ozone, sulphur dioxide and hydro carbons. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;strong&gt;The OMI map shows a red colour over The Netherlands but according to surface measurements of the Dutch National Institute of Public Health and the Environment (RIVM) it just minor smog. What causes the difference?&lt;/strong&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The surface measurements from RIVM are related to the European norms for smog. Those norms are related to a peak level surface concentration. The threshold level is an average concentration of 200 microgram/m3 NO2 during one hour. The peak levels should not exceed this threshold more than 18 hours per year. Peak levels concentrations are most of the time well below the threshold values and therefore one speaks of minor smog. &#xA;  OMI does not measure the concentration at the surface directly. Instead, OMI measures the total amount of nitrogen dioxide (NO2) in a column up to about 10 km. For this column amount there are no direct European norms. The relation between column amounts as measured by satellites and surface concentrations is complicated. Therefore, a red coloured area in the OMI map cannot be related directly to European norms and no conclusion with respect to exceeding some norm can be drawn from the OMI maps. &#xA;  The colours in the OMI maps are chosen in such a way that you can clearly see the difference between different areas. Column amounts of 20 x 10 power 15 molecules per cm2 and higher all have same red-purple colour.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;strong&gt;Can OMI measurements be related to ground level concentrations, like those being measured by the Dutch National Institute of Public Health and the Environment (RIVM)?&lt;/strong&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The largest contribution to the measured NO2 column amount is located in the boundary layer. This is the bottom layer of the atmosphere in which air is mixed quite rapidly and in which the NO2 concentrations are relatively constant. The height of boundary layer varies between a few hundred meters till a few kilometres. The height varies during the day and depends on the weather and season of the year. A rough estimate of the NO2 surface concentration can be calculated by dividing the column amount with the height of the boundary layer.&#xA;  A study, using a chemical model of the atmosphere, showed that NO2 measurements by satellites are consistent with surface measurements and that the red-purple coloureds area roughly have surface concentration of 40 microgram/m3 NO2. This value is similar to the European threshold norm for the year-average concentration.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2018-03-03T20:36:03.733" LastActivityDate="2018-03-03T20:36:03.733" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13539" PostTypeId="2" ParentId="7659" CreationDate="2018-03-03T20:55:18.197" Score="1" Body="&lt;p&gt;My guess is streams fed by mountains that have been tectonically compressed and is undergoing some rotation. Near Italy are 3 tectonic boundary. Convergent, transform, and divergent. Due to the plate motion of the Eurasian plate, to the African plate, and the Arabian plate, it is causing compression and what I can describe as some rotation the land. It appears to be an involved relationship. I used Google Earth to create this map:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NHf6L.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NHf6L.jpg&quot; alt=&quot;Image of eastern Med and Caspian&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope I helped or gave you a direction to look. As you can see by the arrows, there are areas of convergence that are oblique and related in a way, that his geologic feature is not at all impossible.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Other sources&lt;/h3&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.google.com/search?q=geology+of+the+trasnsylvanian+alsp&amp;amp;ie=utf-8&amp;amp;oe=utf-8&amp;amp;client=firefox-b-1-ab&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google search&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://emmanolanlaquilaearthquakeitaly2009.weebly.com/cause.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earthquakes in Italy&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="12371" LastEditorUserId="28050" LastEditDate="2018-03-05T16:43:46.067" LastActivityDate="2018-03-05T16:43:46.067" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13540" PostTypeId="2" ParentId="9822" CreationDate="2018-03-03T21:17:37.360" Score="7" Body="&lt;p&gt;The magnitude of an earthquake is related to the total energy released, therefore to estimate it from a seismogram you need to know the distance to the source. In the case of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Richter_magnitude_scale&quot; rel=&quot;nofollow noreferrer&quot;&gt;Richter scale&lt;/a&gt; for example, the relationship between magnitude and seismogram amplitude is defined for a standard distance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have only one seismograph, you can not triangulate the location of the source (&lt;a href=&quot;https://en.wikipedia.org/wiki/Hypocenter&quot; rel=&quot;nofollow noreferrer&quot;&gt;hypocenter&lt;/a&gt;). Therefore, you can not estimate the magnitude of a seismic event (Richter or &lt;a href=&quot;https://en.wikipedia.org/wiki/Moment_magnitude_scale&quot; rel=&quot;nofollow noreferrer&quot;&gt;moment magnitude&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;But you can estimate the &lt;a href=&quot;https://en.wikipedia.org/wiki/Seismic_intensity_scales&quot; rel=&quot;nofollow noreferrer&quot;&gt;local seismic intensity&lt;/a&gt; of the event&lt;/strong&gt; at the particular location of your instrument. With the accelerometer data you can easily measure the &lt;a href=&quot;https://en.wikipedia.org/wiki/Peak_ground_acceleration&quot; rel=&quot;nofollow noreferrer&quot;&gt;peak ground acceleration&lt;/a&gt;, that can be used to estimate the intensity in any of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Seismic_intensity_scales&quot; rel=&quot;nofollow noreferrer&quot;&gt;existing scales&lt;/a&gt;. For example, the peak ground accelerations associated to each intensity level in the commonly used &lt;a href=&quot;https://en.wikipedia.org/wiki/Mercalli_intensity_scale&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mercalli intensity scale&lt;/a&gt; are:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/F6aGo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/F6aGo.png&quot; alt=&quot;table of intensities&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Those &lt;em&gt;g&lt;/em&gt; values would be easy to calculate with the accelerometer data and proper calibration constants.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Table taken from the Wikipedia page for &lt;a href=&quot;https://en.wikipedia.org/wiki/Peak_ground_acceleration&quot; rel=&quot;nofollow noreferrer&quot;&gt;peak ground acceleration&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might want to have a look at &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4681/characterizing-earthquakes-using-accelerometer-data&quot;&gt;this question&lt;/a&gt;. There are some nice answers and references that you might find useful.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-06T00:16:08.117" LastActivityDate="2018-03-06T00:16:08.117" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13541" PostTypeId="2" ParentId="13509" CreationDate="2018-03-03T22:33:40.847" Score="17" Body="&lt;p&gt;The Ural mountains are one of the oldest mountain ranges on Earth. They started forming about 300 Ma ago by the subduction of the oceanic crust once attached to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Kazakhstania&quot; rel=&quot;noreferrer&quot;&gt;Kazakhstania&lt;/a&gt; plate under the ancient &lt;a href=&quot;https://en.wikipedia.org/wiki/Euramerica&quot; rel=&quot;noreferrer&quot;&gt;Laurussia&lt;/a&gt; continent. A subduction process that finished about 240 Ma ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The tectonic plates are far from fixed, some of them disappear over time other new ones can form, they can move, merge and split. The ones involved in the formation of the Ural mountains are not currently considered tectonic plates by themselves, they are part of the Eurasian plate now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To understand the scale and magnitud of the changes in the tectonic configuration I strongly recommend you to carefully look at the &lt;a href=&quot;https://www.youtube.com/watch?v=IlnwyAbczog&quot; rel=&quot;noreferrer&quot;&gt;wonderful animation produced by Christopher Scotese&lt;/a&gt;, as part of the &lt;a href=&quot;http://www.scotese.com/&quot; rel=&quot;noreferrer&quot;&gt;PALEOMAP Project&lt;/a&gt;.&#xA;To find the answer to your question, I would recommend you to pay special attention starting on minute 3:10, by following the area that I've highlighted with red lines in the following screenshot of that video: &#xA;&lt;a href=&quot;https://i.stack.imgur.com/1qgAA.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1qgAA.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You will see that 416 Ma ago and before there was an active subduction boundary there inside the red polygon. So mountains were getting formed, the ocean in front of that boundary closed-up and disappear about ~240 Ma ago, giving the final push for the formation of a mountain range, that, if you follow it carefully, corresponds to the Ural mountains we know today.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-03T22:39:21.747" LastActivityDate="2018-03-03T22:39:21.747" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13544" PostTypeId="5" CreationDate="2018-03-04T13:54:26.623" Score="0" Body="&lt;p&gt;A &lt;strong&gt;tropical cyclone&lt;/strong&gt; is another name for a large, dangerous storm that rotates inward around a low pressure system. Tropical cyclones are also known as a &lt;strong&gt;hurricane&lt;/strong&gt; in the Atlantic Ocean or northeastern Pacific Ocean (around most of the Americas) or a &lt;strong&gt;typhoon&lt;/strong&gt; in the northwestern Pacific Ocean near eastern Asia. The term tropical cyclone is used when they form in the South Pacific Ocean and Indian Ocean. Tropic cyclones, hurricanes and typhoons are formed over the ocean and maintain their strength while over water. To form, the water temperature must be near or above 30 C. As soon as they hit land, they immediately start to loose their strength. Depending on where they reach landfall, flooding usually occurs due to the amount of rainfall associated withe the tropical cyclone. The aftermath of a cyclone can be quite serious, depending on what category it was. Cyclones can be categorized from 1 to 5. 5 being the strongest, and 1 the weakest. If a cyclone is not strong enough to be a category 1, it's called a &lt;strong&gt;tropical storm.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="12057" LastEditorUserId="2470" LastEditDate="2018-03-05T01:28:31.190" LastActivityDate="2018-03-05T01:28:31.190" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13545" PostTypeId="4" CreationDate="2018-03-04T13:54:26.623" Score="0" Body="Questions referring to tropical cyclones, hurricanes or typhoons and their behavior; or how much destruction they can cause." OwnerUserId="12057" LastEditorUserId="2470" LastEditDate="2018-03-05T01:13:07.867" LastActivityDate="2018-03-05T01:13:07.867" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13546" PostTypeId="1" AcceptedAnswerId="13547" CreationDate="2018-03-04T17:10:54.233" Score="-1" ViewCount="512" Body="&lt;p&gt;If Earth had enough mass in its own rings, more than the weight of Earth: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;What could it decrease the gravity to?&lt;/li&gt;&#xA;&lt;li&gt;Would the atmosphere have more depth or be thinner?&lt;/li&gt;&#xA;&lt;li&gt;What would the weather be like?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ryxpB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ryxpB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://physics.stackexchange.com/questions/281828/if-earth-had-rings&quot;&gt;https://physics.stackexchange.com/questions/281828/if-earth-had-rings&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="2470" LastEditDate="2018-03-17T11:01:55.200" LastActivityDate="2018-03-19T00:47:37.440" Title="If Earth had rings would gravity exerted by Earth decrease?" Tags="|meteorology|earth-history|weather-forecasting|gravity|evolution|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13547" PostTypeId="2" ParentId="13546" CreationDate="2018-03-04T18:47:33.267" Score="10" Body="&lt;p&gt;Rings wouldn't decrease the gravity much, but the exact amount would depend on the exact geometry of the rings. One reason is that the gravity of one side of the ring would partially cancel the attraction of the other side. In a similar fashion described by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Shell_theorem&quot; rel=&quot;nofollow noreferrer&quot;&gt;Shell theorem&lt;/a&gt; demonstrated long ago by Newton and proving that if you are inside a &lt;strong&gt;shell of mass&lt;/strong&gt; the gravity effects from one side cancel the other, therefore it would be no gravity inside the shell. However, in the case of a ring the forces only fully cancel at the very center. Nevertheless, partial cancellation of forces would make that the gravity of a &quot;Earth's mass&quot; ring would be much weaker than the one of an &quot;Earth's mass&quot; planet. For the rings to significantly reduce the acceleration of gravity on Earth's surface you would need super-massive rings (and note the rings with the mass of the Earth would fall in this category), something that is extremely unlikely, as such massive rings would coalesce into moons. In the case of Saturn's rings, they only have the equivalent to a 0.000005% of the mass of Saturn. If such super-massive rings coalesce into moons, those moons could be more massive than Earth's itself, so Earth would be orbiting the moons more than the other way around. More precisely you would have a chaotic multiple-body system, in which Earth would be just one of the bodies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is worth noting that even our moon doesn't have much of an effect in the acceleration of gravity despite the mass is fairly large (1.2% of Earth's mass) and it is all concentrated in one place (instead of distributed in a ring). The &lt;a href=&quot;https://en.wikipedia.org/wiki/Moon&quot; rel=&quot;nofollow noreferrer&quot;&gt;mass of the moon is 7.3e22 kg&lt;/a&gt;, which is for comparison about &lt;strong&gt;2000 times&lt;/strong&gt; more than the &lt;a href=&quot;https://en.wikipedia.org/wiki/Rings_of_Saturn#Physical_characteristics&quot; rel=&quot;nofollow noreferrer&quot;&gt;mass of Saturn's rings&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case of the moon for instance, your weight doesn't change at all in high or low tide. That's because the scale that measures your weight, and the ground under it are all suffering the same tidal effect than you, so the force your mass put on the scale is unaffected by the presence of the moon. And the same would be true for your hypothetical super-massive rings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding to your second question, for all the above, I doubt it would change significantly the thickness of the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, when it comes to weather it is a completely different story. The presence of the rings could strongly decrease the amount of solar radiation reaching the tropics, therefore it could change the whole &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_circulation&quot; rel=&quot;nofollow noreferrer&quot;&gt;global atmospheric circulation pattern&lt;/a&gt;, maybe the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hadley_cell&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hadley cell&lt;/a&gt; wouldn't form as we know it, changing the climates worldwide.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-19T00:47:37.440" LastActivityDate="2018-03-19T00:47:37.440" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13548" PostTypeId="2" ParentId="2519" CreationDate="2018-03-04T22:10:09.007" Score="0" Body="&lt;p&gt;Dissolved micro particles of calcium carbonate, aluminum etc in the water coupled light reflection and resultant spectral wave cause various color in the lake water. It is unlike algie (red) found in Red Sea.&#xA;Light reflection and depth is a major factor because the same water look regular water in s test tube.&lt;/p&gt;&#xA;" OwnerUserId="12374" LastActivityDate="2018-03-04T22:10:09.007" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13549" PostTypeId="2" ParentId="2393" CreationDate="2018-03-04T23:22:10.907" Score="0" Body="&lt;p&gt;Gold is found all over the world. Where it happens to be most economic to mine depends on a range of random factors, including political factors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One big factor in gold mining is the cost of labor. Places where labor rates are low are more likely to have people mining gold. There are places in Africa where people dig up gold with their bare hands.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is probably plenty of gold left in California, but do you really want to restart hydraulic mining, washing entire mountains into mud to get that gold? Hydraulic mining was banned in California over a 100 years ago, but hey as long as you are willing to destroy every mountain in the Sacramento valley, we could start it up again and turn California into a gold mining district.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DDHRF.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DDHRF.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[Above] &lt;strong&gt;Hydraulic mining&lt;/strong&gt;. We could make California a gold mining region again, but do we want to?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastEditorUserId="2491" LastEditDate="2018-03-05T00:19:56.353" LastActivityDate="2018-03-05T00:19:56.353" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13550" PostTypeId="1" CreationDate="2018-03-05T04:23:18.003" Score="3" ViewCount="1500" Body="&lt;p&gt;I have been researching everywhere. At what level of the atmosphere do carbon dioxide and other greenhouse gases occur?  I can't get a straight answer and am frustrated...&lt;/p&gt;&#xA;" OwnerUserId="12375" LastEditorUserId="11908" LastEditDate="2019-03-11T23:20:24.103" LastActivityDate="2019-03-11T23:20:24.103" Title="The atmosphere and the dispersion of greenhouse gases" Tags="|atmosphere|climate-change|greenhouse-gases|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13551" PostTypeId="2" ParentId="13550" CreationDate="2018-03-05T04:49:11.910" Score="7" Body="&lt;p&gt;The short answer is that &lt;strong&gt;greenhouse gases occur at all levels in the atmosphere&lt;/strong&gt;. However, the concentrations can vary with altitude. In the case of greenhouse gases that are always in a gaseous state like CO2, Methane and Nitrous oxide, they are evenly distributed throughout the lower atmosphere (i.e. troposphere and stratosphere below ~20km), (&lt;a href=&quot;https://earthscience.stackexchange.com/questions/13144/why-air-do-not-suffer-density-stratification-of-its-gaseous-components&quot;&gt;this question &amp;amp; answer&lt;/a&gt; explain why), with only minor variations in concentration. The only notable exception is water vapour, also a powerful greenhouse gas, water is the only one that do transition between liquid, solid and gaseous states within the atmosphere, something that have as a consequence that its distribution is not homogeneous like it is for the other gases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The actual distribution of water vapour is highly variable, something that we all know from the daily experiences of a diversity of conditions like dry weather, fog, rain, etc. However, there is some clear patterns:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Vertically, water vapor abundance falls more or less logarithmically, as it can be seen in the following figure:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5gNu7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5gNu7.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(taken from &lt;a href=&quot;https://www.eso.org/gen-fac/pubs/astclim/espas/pwv/mockler.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;AGU WATER VAPOR in the CLIMATE SYSTEM, Special Report. December 1995&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Were it falls from about 3 grams per kilogram of dry air to about 0.003 grams per kilogram of dry air at 15,000 meters of elevation. A big contrast with the tropospheric variations in CO2 for example, that are in the order of ~3-6% across the glove, with a ~1-2% &lt;a href=&quot;https://en.wikipedia.org/wiki/Keeling_Curve&quot; rel=&quot;nofollow noreferrer&quot;&gt;seasonal cycle&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Horizontally, across the surface of the Earth, water it is much more abundant in the tropics than the poles, a pattern mostly controlled by temperature, because the capacity of air to hold dissolved water falls exponentially with temperature (as described by the first equation in my answer to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13159/how-to-calculate-humidity-using-outside-temperature-and-outside-relative-humidit/13198#13198&quot;&gt;this question&lt;/a&gt;). The following figure of the global mean water column derived from satellite data for 2009 will gives you a good sense of the typical distribution&#xA;&lt;a href=&quot;https://i.stack.imgur.com/uIC9m.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uIC9m.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;(taken from &lt;a href=&quot;http://www.globvapour.info/newsarchive.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Retrieval of total precipitable water from GOME-1, SCIAMACHY and GOME-2&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, if we consider higher levels of the atmosphere (&gt;20 km), the mixing at that scale is not strong enough to smooth out the variations in concentration that arise due to the existence of sources and sinks for each greenhouse gas.&#xA;For example, methane is produced in the surface by natural and anthropocentric sources, and the biggest sink (90%) is the oxidation by hydroxyl radicals (OH) in the stratosphere. This create a fairly large vertical gradient in methane concentration. A gradient that gets smoothed out by strong mixing in the troposphere but becomes very important in the stratosphere and mesosphere. Similar phenomena creates gradients of other greenhouse gases like N2O, Ozone, and to a lesser extent CO2. These processes are nicely explained in &lt;a href=&quot;http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.532.2310&amp;amp;rep=rep1&amp;amp;type=pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt;, were the following figure gives a great summary of the changes in concentration of most gases in the atmosphere:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/rdOEV.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rdOEV.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here you can see that, CO2 keeps a relatively fix abundance throughout the atmosphere up to 120 km, while N2O is relatively very scarce above 60 km, and Ozone below 10 km.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-07T02:51:09.790" LastActivityDate="2018-03-07T02:51:09.790" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13552" PostTypeId="2" ParentId="13495" CreationDate="2018-03-05T14:35:31.263" Score="1" Body="&lt;p&gt;Here's a couple of terms that describe what you're asking for: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(a guess I'm sort of adding to @Fred's list)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Balanced system&lt;/li&gt;&#xA;&lt;li&gt;Stable system&lt;/li&gt;&#xA;&lt;li&gt;Revertible system&lt;/li&gt;&#xA;&lt;li&gt;Reproducible system&lt;/li&gt;&#xA;&lt;li&gt;Regressive system&lt;/li&gt;&#xA;&lt;li&gt;Reconstructive system&lt;/li&gt;&#xA;&lt;li&gt;Reestablishing system&lt;/li&gt;&#xA;&lt;li&gt;Re-creative system&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="12057" LastActivityDate="2018-03-05T14:35:31.263" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13553" PostTypeId="1" AcceptedAnswerId="16033" CreationDate="2018-03-05T14:57:27.643" Score="5" ViewCount="201" Body="&lt;p&gt;In &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/1520-0493%281994%29122%3C0814%3AOOTDTO%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt; reviewing the Madden-Julian Oscillation, frequently geostrophic theory (or approximately geostrophic) is often invoked. However, for geostrophic theory to be invoked, $$Ro=\frac{U}{f_0L}&amp;lt;&amp;lt;1$$. However, along the equator, $f_0=0$ and near the equator, $f_0\approx0$, which makes $Ro&amp;gt;&amp;gt;1$. But since this is a published paper, shouldn't the editor or reviewers caught this problem?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some examples:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Page 815, second to last paragraph in the first column: &quot;These results are consistent with an oscillation that is -- at 850 hPa at least-- in approximate geostrophic balance.&quot;&lt;/li&gt;&#xA;&lt;li&gt;Page 816, first paragraph in the second column: &quot;For geostrophic balance, the in-phase relationship is consistent with maximum pressure variations at the equator, while the more nearly out of phase relationship suggests maximum pressure variations off the equator.&quot;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2018-03-12T20:42:03.080" LastActivityDate="2019-01-25T15:47:18.033" Title="Why would geostrophic theory be invoked in the tropics with regards to the MJO?" Tags="|meteorology|climatology|fluid-dynamics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13554" PostTypeId="1" CreationDate="2018-03-05T15:43:44.000" Score="1" ViewCount="159" Body="&lt;p&gt;We know that warm air rises in the atmosphere due to the reduced density of the parcel itself. But in the eye of a tropical cyclone the warm air sinks down and does not reach the surface, but gets carried away by strong updrafts. Why do we find this sinking warm and dry air sinking in the eye of a tropical cyclone?&lt;/p&gt;&#xA;" OwnerUserId="12377" LastEditorUserId="28050" LastEditDate="2018-03-05T16:36:14.357" LastActivityDate="2018-03-05T16:36:14.357" Title="Why does hot air sink in the eye of a tropical cyclone?" Tags="|meteorology|tropical-cyclone|storms|" AnswerCount="0" CommentCount="5" ClosedDate="2019-02-11T21:47:15.040" ContentLicense="CC BY-SA 3.0" />
  <row Id="13555" PostTypeId="1" AcceptedAnswerId="13573" CreationDate="2018-03-06T11:18:17.330" Score="3" ViewCount="290" Body="&lt;p&gt;As I'm a newbie in seismology and related area, I would like to know which type of seismic sensors usually used in earthquake early warning systems?&lt;/p&gt;&#xA;" OwnerUserId="12381" LastActivityDate="2018-03-08T21:08:21.553" Title="Which type of seismic sensors usually used in Earthquake Early Warning?" Tags="|earthquakes|seismology|seismic|instrumentation|environmental-sensors|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13557" PostTypeId="1" CreationDate="2018-03-06T15:40:57.460" Score="12" ViewCount="4441" Body="&lt;p&gt;I live in a city where the pollution is bad, so bad that sometimes we get 'fake' rain (from &lt;a href=&quot;https://en.wikipedia.org/wiki/Cloud_seeding&quot; rel=&quot;noreferrer&quot;&gt;cloud seeding&lt;/a&gt;). This may last for an extended period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There have been times before when it has “rained” and it might as well have been raining.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This seems to defy some sort of logic though. Natural rain and human produced rain must have some fundamental differences, should they not?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What differences exist between natural rain and human “rain”?&lt;/p&gt;&#xA;" OwnerUserId="10853" LastEditorUserId="6465" LastEditDate="2018-03-07T09:03:45.000" LastActivityDate="2023-05-13T18:36:17.727" Title="How to tell the difference between real rain and fake rain (cloud seeding)?" Tags="|meteorology|clouds|air-pollution|rain|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13558" PostTypeId="1" AcceptedAnswerId="13572" CreationDate="2018-03-06T20:27:15.733" Score="9" ViewCount="1754" Body="&lt;p&gt;Geologist have theorized that the Tethys Sea subducted under Eurasian plates. But where are the volcanoes that would have resulted due to this? Where are the volcanoes in the Alps and the Himalayas?&lt;/p&gt;&#xA;" OwnerUserId="12045" LastActivityDate="2018-03-08T19:43:17.317" Title="Volcanoes in the Alps and Himalayas and the subduction of Tethys Sea" Tags="|geology|volcanology|plate-tectonics|mountains|subduction|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13559" PostTypeId="1" CreationDate="2018-03-07T00:24:05.690" Score="2" ViewCount="67" Body="&lt;p&gt;Since tunnelling is like making a giant horizontal core sample, what did the analysis of the extracted rocks teach us? Is the inside homogeneous or layered, are there &quot;deformations&quot;, etc?&lt;/p&gt;&#xA;" OwnerUserId="160" LastEditorUserId="94" LastEditDate="2018-03-07T16:06:07.627" LastActivityDate="2018-03-07T16:06:07.627" Title="What did tunnel digging teach us about the formation of chains of mountains?" Tags="|mountains|structural-geology|stratigraphy|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13560" PostTypeId="2" ParentId="13559" CreationDate="2018-03-07T02:00:12.203" Score="3" Body="&lt;p&gt;Tunnels have provided nothing more than what was learned from conventional geological drilling and surface mapping. Tunnels provide supplemental information. Very rarely do they provide &quot;make or break&quot; information that is pivotal to geological understanding on a large scale.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A tunnel is a lateral large diameter hole. Geological drilling produces small diameter holes, whose orientation can be lateral, vertical or anything in between. A sample of rock is take by both.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By using in-hole surveys and noting from where, within a hole, a sample was taken from it is possible to know where the rock sample came from. This is useful for creating geological maps of the region. It is even possible to place ground stress measuring devices in both drill holes and tunnels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mass of material taken from a hole, whether it be a geological drill hole or a tunnel is not particularly significant in expanding knowledge. More knowledge can be gained from multiple small samples taken over a large area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tunnels do give geologists the advantage of walking through a rock mass and seeing &lt;em&gt;some&lt;/em&gt; structures like faults. But if the tunnel hasn't intersected a structure then the geologists may not know about it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your question is a bit like asking &quot;what can be learn about a country by just walking along its roads&quot;. Additional information can be gained by walking off track, navigating rivers, flying over the country and talking to the inhabitants.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tunnels provide &lt;strong&gt;some&lt;/strong&gt; information. It is useful information, but multiple sources of information given us a better understanding.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-03-07T02:00:12.203" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13561" PostTypeId="1" AcceptedAnswerId="13574" CreationDate="2018-03-07T08:46:22.917" Score="4" ViewCount="80" Body="&lt;p&gt;I'm a hydrologist with a good background in GIS. I'm looking for a reference (Methodology, Technical guide) for identification of temporary, intermittent and perennial streams. I google and only found &lt;a href=&quot;https://www.fs.fed.us/rm/pubs_rm/rm_gtr245.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this reference&lt;/a&gt; for North Carolina.Is there any standard reference guide for such an identification?&lt;/p&gt;&#xA;" OwnerUserId="787" LastActivityDate="2018-03-09T00:09:44.110" Title="Looking for a reference for identifing stream regimes(Intermittent, Perennial)" Tags="|hydrology|rivers|reference-request|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13562" PostTypeId="2" ParentId="13557" CreationDate="2018-03-07T08:54:48.430" Score="6" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;What differences exist between natural rain and human “rain”?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The only physically measurable difference between rain from seeded clouds and unseeded is in the seeds/ cloud condensation nuclei/ aerosols that are the surface that moisture can condensate onto and form cloud droplets.&lt;/p&gt;&#xA;&lt;h2&gt;Measurements&lt;/h2&gt;&#xA;&lt;p&gt;You could collect rainwater, evaporate it and the remaining solids were the substances acting as cloud condensation nuclei. This process would get some aerosols from the ambient air, but simultaneously using a device for collecting aerosols and reducing their composition from the rainwater one would lessen this problem. After analyzing the solids one could do some guesswork whether the aerosols were natural or influenced by humans. For example if there is actually deliberate cloud seeding happening you could find traces of silver iodide. Most likely this is not the case and simply heavy pollution has a significant impact on formation of aerosols that can act as cloud condensation nuclei. In this case there are probably some compounds that can be formed only in combustion processes and finding them would mean that they played a role on the formation of the clouds. Doing this experiment in otherwise similar locations with the other having much more pollution would probably be the sanest option. Even after all this you still wouldn't be able to accurately tell whether it would've rained more or less without the pollution. If the air is clean to begin with, adding pollution and thus aerosols the cloud formation would be enhanced and probably then rain too. But if the air already has enough cloud condensation nuclei to begin with then adding aerosols might have the opposite effect; moisture would condense into many small droplets rather a few big ones that create rain.&lt;/p&gt;&#xA;&lt;h2&gt;Modelling&lt;/h2&gt;&#xA;&lt;p&gt;Another possibility would be to study this using a weather model with aerosol dynamics included using measurements of the given location to verify the results. And when the model simulates the reality accurately enough you could tamper with the aerosol fields (by adding and reducing aerosols) and see how the rain is affected. I'm not aware how accurate these kind of models are currently, but aerosol dynamics can make the model easily very heavy.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-03-07T15:37:52.100" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13564" PostTypeId="1" CreationDate="2018-03-07T16:43:18.750" Score="3" ViewCount="8280" Body="&lt;p&gt;I have a parcel of air at 30°C with a dew point temp of 15°C.  It goes up and then back down a mountain 4km in height. Assuming the normal and dry adiabatic lapse rates apply, and an ELR=7.5°C/km, with the environment also at 30°C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From Wikipedia it says that to find cloud base I:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1). Start at the initial temperature (T) and pressure of the air parcel and follow the dry adiabatic lapse rate line upward (provided that the RH in the air parcel is less than 100%, otherwise it is already at or above LCL).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So then the initial temp is 30*C not sure what it means to follow the dry adiabatic lapse rate line upwards.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that lapse rate is the rate at which Earths atmosphere increases and decreases in conguence with the altitude. So the temperature increases when the altitude decreases and the temperature decreases when the altitude increases. So a dry unsaturated lapse rate is one where the parcel lacks water content, and the saturated lapse rate is one where the parcel is moist and contains water content. I understand that when they warm or cool both types move in up and down in direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2). From the initial dew point temperature (Td) of the parcel at its starting pressure, follow the line for the constant equilibrium mixing ratio (or &quot;saturation mixing ratio&quot;) upward.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not sure what this means&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(3). The intersection of these two lines is the LCL.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not sure what this is asking me to do.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Things I have been asked to provide include:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;a) the elevation at which clouds will occur (the lifting condensation&#xA;  level);&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;b) the temperature of the parcel at the top of the mountain;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;c) the temperature the parcel will have when it descends to the bottom&#xA;  on the far side of the mountain;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;d) the portions of its journey where it follows the wet and dry rates&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;e) explain why the parcel is warmer/cooler/same temperature on the&#xA;  back side of the mountain as compared to when it started.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="12218" LastEditorUserId="6298" LastEditDate="2018-03-08T16:16:51.053" LastActivityDate="2020-12-28T17:25:52.917" Title="How do you calculate the elevation at which clouds will form (lifting condensation level)?" Tags="|atmosphere|homework|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13566" PostTypeId="1" AcceptedAnswerId="13571" CreationDate="2018-03-07T23:26:10.087" Score="11" ViewCount="683" Body="&lt;p&gt;I saw many contradictions everywhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, my geography textbook says that Atacama Desert is a desert where foggy weather is common, and it persists almost the whole year. Whereas every astronomer will say that it is the place with least clouds and fog, which is why it is one of the best places for astronomical observations beyond the dark sky.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, which is true? And if one of them is not true, then how did it gain popularity at all?&lt;/p&gt;&#xA;" OwnerUserId="6148" LastEditorUserId="11908" LastEditDate="2019-02-03T20:19:44.640" LastActivityDate="2019-02-03T20:19:44.640" Title="Is Atacama Desert cloudy or cloudless most of the year?" Tags="|climate|geography|climatology|desert|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13568" PostTypeId="2" ParentId="13566" CreationDate="2018-03-08T13:18:26.953" Score="7" Body="&lt;p&gt;Atacama desert is cloudless most part of the year. Except for the litoral, where a fog from the sea goes inland. This phenomena is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Camanchaca&quot; rel=&quot;noreferrer&quot;&gt;camanchaca&lt;/a&gt;.&#xA;Telescopes for astronomy are located in high places, not only to avoid this weather, but also because at high altitudes the atmosphere is thinner and the weather is dry, both good for observation.&#xA;Besides, during the night most astronomy observations are done, while the camanchaca is stronger during the morning.&lt;/p&gt;&#xA;" OwnerUserId="5004" LastActivityDate="2018-03-08T13:18:26.953" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13570" PostTypeId="2" ParentId="13511" CreationDate="2018-03-08T17:34:40.157" Score="3" Body="&lt;p&gt;The online calculator is giving you the specific humidity, which at a relative humidity of 43% is 43% of the saturation specific humidity at that temperature. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reading from the chart, a rough estimate for the saturation specific humidity is ~37.5 g/kg at 35°C. 43% of this is 16.1 g/kg, which is close to the value given by the calculator.&lt;/p&gt;&#xA;" OwnerUserId="6443" LastActivityDate="2018-03-08T17:34:40.157" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13571" PostTypeId="2" ParentId="13566" CreationDate="2018-03-08T18:56:27.973" Score="14" Body="&lt;p&gt;The Atatacma desert comprise a very large area of &lt;a href=&quot;https://en.wikipedia.org/wiki/Atacama_Desert&quot; rel=&quot;noreferrer&quot;&gt;more than 100,000 square kilometers&lt;/a&gt;, that host very different climates. The main factors driving the climatic variability are the distance to the Pacific ocean and elevation. This latter factor is very strong, as the Atacama desert covers a formidable elevation range, from sea level to almost 7,000 m, at the summit of &lt;a href=&quot;https://en.wikipedia.org/wiki/Ojos_del_Salado&quot; rel=&quot;noreferrer&quot;&gt;Ojos del Salado&lt;/a&gt;, the highest volcano in the world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The highest areas, that also happen to be further of the sea, are the driest and less cloudy. The weather pattern you mention of common foggy conditions only happens very close to the coast, &lt;a href=&quot;http://observatoriogeograficoamericalatina.org.mx/egal8/Procesosambientales/Climatologia/10.pdf&quot; rel=&quot;noreferrer&quot;&gt;extending inland only about 10 km or a few tens of kilometers trough low lying valleys&lt;/a&gt;. And is produced by fog that forms over the sea penetrate inland. It is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Camanchaca&quot; rel=&quot;noreferrer&quot;&gt;camanchaca&lt;/a&gt;, but it doesn't cross the coastal mountain range.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The pattern of cloudiness throughout the desert can be visualized using a dataset produced by NASA's &lt;a href=&quot;https://eosweb.larc.nasa.gov/cgi-bin/sse/sse.cgi?skip@larc.nasa.gov&quot; rel=&quot;noreferrer&quot;&gt;Surface meteorology and Solar Energy&lt;/a&gt;, in particular the satellite derived &lt;a href=&quot;https://eosweb.larc.nasa.gov/cgi-bin/sse/subset.cgi?email=skip@larc.nasa.gov&quot; rel=&quot;noreferrer&quot;&gt;Monthly Averaged Clear Sky Days&lt;/a&gt; (i.e. cloud cover less than 10%) over a 22-year period (July 1983 - June 2005). It has a resolution of 1°, so about 110 km here. That means that the central area of the desert is covered by just 12 cells, nevertheless it will be enough to see the pattern I mention.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following figure shows the central section of the Atacama dessert using official &lt;a href=&quot;https://www.igm.cl/&quot; rel=&quot;noreferrer&quot;&gt;IGM&lt;/a&gt; 1:500.000 maps in the left. And the mean clear skies dataset on the right for the very same area. The numbers refer to the 22-year mean clear sky days per month.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/DWQ9E.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DWQ9E.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now the interpretation will be easier if we overlay those two figures as in one as shown below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cDMmf.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cDMmf.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From there you can see how there is a fairly large variability in the amount of clear sky days. From a few at the coast, to about a week over the coastal mountains to about two weeks east of the coastal mountains. Peaking at 17 days per month over the &lt;a href=&quot;https://en.wikipedia.org/wiki/Salar_de_Atacama&quot; rel=&quot;noreferrer&quot;&gt;Salar de Atacama&lt;/a&gt; (a value surpassed only by the Sahara desert and the interior of Antarctica). Then, it is no coincidence that &lt;a href=&quot;http://www.almaobservatory.org/en/home/&quot; rel=&quot;noreferrer&quot;&gt;ALMA observatory&lt;/a&gt;, the largest radio telescope in the world, is located there, just east of the salar de Aatacama.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As mentioned before, topography is the main factor controlling this pattern. Even close to the coast, some mountain tops can have remarkable clear sky records, as is the case of the 2,635 m high &lt;a href=&quot;https://en.wikipedia.org/wiki/Cerro_Paranal&quot; rel=&quot;noreferrer&quot;&gt;Mount Paranal&lt;/a&gt; were the &lt;a href=&quot;https://www.eso.org/public/teles-instr/paranal-observatory/&quot; rel=&quot;noreferrer&quot;&gt;VLT observatory&lt;/a&gt; is located at just 15 km from the coast (falling on the lower left cell with 9 clear sky days in the figure above).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, going back to your question: Both the astronomers and your geography text book are right, but each one is referring to a different area of the Atacama desert. And looking at the above data, it is right to say that the coastal part of the Atacama desert is cloudy most of the year. However, a fairly large area in the interior is cloudless most of the year.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-09T20:48:01.950" LastActivityDate="2018-03-09T20:48:01.950" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13572" PostTypeId="2" ParentId="13558" CreationDate="2018-03-08T19:43:17.317" Score="8" Body="&lt;p&gt;The end of the Tethys Sea and the initiation of the continent-continent collision that formed the Himalayas is thought to have happened about 65 Ma ago (&lt;a href=&quot;https://phys.org/news/2012-10-rewriting-himalayan-history-ancient-oceans.html&quot; rel=&quot;noreferrer&quot;&gt;recent studies&lt;/a&gt; suggest maybe only 35 Ma). And since then, that colossal collision have produced an &lt;a href=&quot;https://en.wikipedia.org/wiki/Geology_of_the_Himalaya#The_making_of_the_Himalaya&quot; rel=&quot;noreferrer&quot;&gt;estimated 2,500 km of crustal shortening&lt;/a&gt;.  That means that 2,500 km of continental surface is gone. A fraction of it was maybe subducted, other fraction squeezed under the other continent and perhaps the larger fraction shortened by thrust and folding. This massive transformation would have been enough to erase a preexisting volcanic arc, that could easily end up under kilometers of rock that came from sediments in the Tethys sea or the sourthern edge of the Eurasian plate (for example mount &lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Everest#Geology&quot; rel=&quot;noreferrer&quot;&gt;Everest summit is mostly composed of sedimentary rocks&lt;/a&gt; with fragments of trilobites from the Tethys sea).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nevertheless, part of that volcanic arc indeed is visible now in the surface. No volcanic edifice have survived the cataclysm that give rise to the Himalayas, but the rocks that formed the arc are now known as the Dras Volcanics, a band of volcanic basalts and dacites outcrops that are part of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Indus-Yarlung_suture_zone&quot; rel=&quot;noreferrer&quot;&gt;Indus suture zone&lt;/a&gt;. And that are though to originate in the Mesozoic (from about 252 to 66 Ma ago) volcanic arc that existed in the Eurasia plate as a consequence of the subduction of the oceanic crust under the Tethys sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This geological map of the Himalayas shows in geen the outcrops of the Indus suture zone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/U4FLm.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/U4FLm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Taken from &lt;a href=&quot;https://www.researchgate.net/publication/311519632_The_Tethyan_Himalayan_detrital_record_shows_that_India-Asia_terminal_collision_occurred_by_54_Ma_in_the_Western_Himalaya&quot; rel=&quot;noreferrer&quot;&gt;The Tethyan Himalayan detrital record shows that India–Asia terminal collision occurred by 54 Ma in the Western Himalaya&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-03-08T19:43:17.317" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13573" PostTypeId="2" ParentId="13555" CreationDate="2018-03-08T21:08:21.553" Score="4" Body="&lt;p&gt;Accelerometers, preferably triaxial (i.e., those that record horizontal and vertical motion). Beyond that your question is indeed a bit too open-ended. Some use many cheap MEMS (&lt;a href=&quot;http://onlinelibrary.wiley.com/doi/10.1029/2008GL036572/epdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://onlinelibrary.wiley.com/doi/10.1029/2008GL036572/epdf&lt;/a&gt;; &lt;a href=&quot;https://www.theverge.com/circuitbreaker/2017/7/13/15963996/raspberry-pi-seismograph-early-warning-earthquakes&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.theverge.com/circuitbreaker/2017/7/13/15963996/raspberry-pi-seismograph-early-warning-earthquakes&lt;/a&gt;; these are similar to those found in phones), some use more expensive but reliable equipment (&lt;a href=&quot;https://kinemetrics.com/post_products/episensor-es-t/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://kinemetrics.com/post_products/episensor-es-t/&lt;/a&gt;)...&lt;/p&gt;&#xA;" OwnerUserId="12155" LastActivityDate="2018-03-08T21:08:21.553" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13574" PostTypeId="2" ParentId="13561" CreationDate="2018-03-09T00:09:44.110" Score="2" Body="&lt;p&gt;I'm not sure if this is a standard per se, but I found it useful.  These definitions are from a 1923 publication of the United States Department of the Interior entitled Outline of Ground-Water Hydrology.  &lt;a href=&quot;https://pubs.er.usgs.gov/publication/wsp494&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; is the link to the PDF and the specific definitions below can be found on pages 57-58.  Hope this helps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Perennial:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;blockquote&gt;&#xA;  &lt;p&gt;A perennial stream, or stretch of a stream, is one which flows&#xA;  continuously. Perennial streams are generally fed in part by springs,&#xA;  and their upper surfaces generally stand lower than the water table in&#xA;  the localities through which they flow.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Intermittent streams are divided into spring-fed intermittent streams and surface-fed intermittent streams.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;blockquote&gt;&#xA;  &lt;p&gt;A spring-fed intermittent stream, or stretch of a stream, is one that&#xA;  flows only at certain times when it receives water from springs. The&#xA;  intermittent character of streams of this type is generally due to&#xA;  fluctuations of the water table whereby the stream channels stand a&#xA;  part of the time below and a part of the time above the water table.&#xA;  This is the ordinary type of intermittent stream.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;blockquote&gt;&#xA;  &lt;p&gt;A surface-fed intermittent stream, or stretch of a stream, is one that&#xA;  flows during protracted periods when it receives water from some&#xA;  surface source, generally the gradual and long-continued melting of&#xA;  snow in a mountainous or other cold tributary area. The term may be&#xA;  arbitrarily restricted to streams or stretches of streams that flow&#xA;  continuously during periods of at least one month.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Ephemeral:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;blockquote&gt;&#xA;  &lt;p&gt;An ephemeral stream, or stretch of a stream, is one that flows only in&#xA;  direct response to precipitation. It receives no water from springs&#xA;  and no long-continued supply from melting snow or other surface&#xA;  source. Its stream channel is at all times above the water table. The&#xA;  term may be arbitrarily restricted to streams or stretches of streams&#xA;  that do not flow continuously during periods of as much as one month.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2018-03-09T00:09:44.110" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13575" PostTypeId="1" AcceptedAnswerId="13576" CreationDate="2018-03-09T17:19:06.283" Score="9" ViewCount="5070" Body="&lt;p&gt;What are the Earth's maximum and minimum orbital speeds around the Sun?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any way to calculate orbital speed at any point of Earth's orbit? Is there a way to relate this to the calendar?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does the change in speed during an orbit around the Sun affect Earth's revolution time around its own axis? (24 hours slightly more or less on day to day basis)&lt;/p&gt;&#xA;" OwnerUserId="12402" LastEditorUserId="11908" LastEditDate="2019-03-11T20:57:04.610" LastActivityDate="2019-03-11T20:57:04.610" Title="Changes in Earth's orbital and rotation speeds" Tags="|geophysics|earth-rotation|earth-system|solar-terrestrial-physics|time|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13576" PostTypeId="2" ParentId="13575" CreationDate="2018-03-09T18:58:11.843" Score="10" Body="&lt;p&gt;The Earth moves faster around the Sun when it is near its perihelion (the closest point of its orbit to the Sun). And it moves slower when it is further away (aphelion), just as &lt;a href=&quot;https://en.wikipedia.org/wiki/Johannes_Kepler&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kepler&lt;/a&gt; realized quite a while ago when enunciating his &lt;a href=&quot;https://en.wikipedia.org/wiki/Kepler%27s_laws_of_planetary_motion&quot; rel=&quot;nofollow noreferrer&quot;&gt;Third Law of Planetary Motion&lt;/a&gt;. There are many ways to write a formula to calculate Earth's speed around the Sun. But for your question I think &lt;a href=&quot;https://en.wikipedia.org/wiki/Orbital_speed&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one&lt;/a&gt; is simple and general enough:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$v= \sqrt{G\,M_S\left(\frac{2}{r}-\frac{1}{a}\right)}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where &lt;em&gt;$v$&lt;/em&gt; is Earth's speed, &lt;em&gt;$G$&lt;/em&gt; is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Gravitational_constant&quot; rel=&quot;nofollow noreferrer&quot;&gt;gravitational constant&lt;/a&gt;, &lt;em&gt;$M_s$&lt;/em&gt; is the mass of the Sun (this equation assumes that the mass of Earth is negligible compared to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Sun&quot; rel=&quot;nofollow noreferrer&quot;&gt;mass of the Sun&lt;/a&gt;, which is a very good approximation), &lt;em&gt;$a$&lt;/em&gt; is &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth's semi-major axis&lt;/a&gt; of orbit (which defines how elliptic or how circular the orbit is), and &lt;em&gt;$r$&lt;/em&gt; is the distance from the Earth to the Sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And the closest and furthest distances respectively are &lt;a href=&quot;https://en.wikipedia.org/wiki/Perihelion_and_aphelion&quot; rel=&quot;nofollow noreferrer&quot;&gt;about 147.1 million kilometers (around January 3) and about 152.1 million kilometers (around July 4)&lt;/a&gt;. Plugging those numbers into the equation you get a &lt;strong&gt;maximum speed of 30.3 km/s and a minimum of 29.3 km/s&lt;/strong&gt;. In contrast, the speed due to Earth's rotation around its own axis, is at most (i.e. in the equator) about 0.5 km/s.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For any given day, the calculation of the distance to the Sun is complicated, but websites like &lt;a href=&quot;https://theskylive.com/sun-tracker&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one&lt;/a&gt;, provide a real time value you can use in the above formula [that site also provides the speed right away!].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These values are basically the same from one year to another. However, they do slowly change as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Orbital_eccentricity&quot; rel=&quot;nofollow noreferrer&quot;&gt;eccentricity&lt;/a&gt; of Earth's orbit gradually varies over a ~400,000 years cycle as described by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;nofollow noreferrer&quot;&gt;Milankovitch cycles&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, for Earth's speed of rotation about its own axis the value is pretty much the same each day; variations are of day length are on the order of &lt;a href=&quot;https://en.wikipedia.org/wiki/Day_length_fluctuations&quot; rel=&quot;nofollow noreferrer&quot;&gt;a fraction of a millisecond&lt;/a&gt;.  Part of that variation is periodic and more or less predictable and another part is from other less predictable factors. But for all practical purposes the length of the day is constant through the year. The following figure shows those tiny variations in day length since the early 1960's:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cy8xi.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cy8xi.png&quot; alt=&quot;daily deviation of length of day&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(image from Wikipedia commons, originally &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Deviation_of_day_length_from_SI_day.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But as a consequence of these tiny variations, almost every year one or two (&lt;a href=&quot;https://en.wikipedia.org/wiki/Leap_second&quot; rel=&quot;nofollow noreferrer&quot;&gt;leap seconds&lt;/a&gt;) are added to our clocks to keep them aligned with the rotation of the Earth. In the long run (millennia), Earth days are getting longer (~&lt;a href=&quot;https://www.scientificamerican.com/article/earth-rotation-summer-solstice/&quot; rel=&quot;nofollow noreferrer&quot;&gt;0.017 milliseconds per year&lt;/a&gt;).  Some of the factors involved were discussed in &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13432/what-is-the-fastest-the-earth-has-ever-spun/13433#13433&quot;&gt;this question&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally to address whether changes in orbital speed affect rotational speed: I don't think so. For what I understand none of those small changes in the length of the day is a direct consequence of changes in the orbital speed. However, despite there is no changes in the speed of rotation, what we generally understand as a day (i.e. the time between two consecutive sunrises, sunsets or noon), is not only controlled by the rotation of the Earth around its axis. In fact, one out of the ~365 days of the year is consequence of Earth's revolution around the Sun, not its rotation. And that one-day contribution give rise to the difference between a day and a &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_rotation#Stellar_and_sidereal_day&quot; rel=&quot;nofollow noreferrer&quot;&gt;sidereal day&lt;/a&gt;, and the variations in the duration of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_time#Apparent_solar_time&quot; rel=&quot;nofollow noreferrer&quot;&gt;apparent solar day&lt;/a&gt;, variations that are directly controlled by Earth's orbital speed and can change the time between solar noon &lt;a href=&quot;https://en.wikipedia.org/wiki/Equation_of_time&quot; rel=&quot;nofollow noreferrer&quot;&gt;up to about 30 seconds&lt;/a&gt; over a year.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-10T18:19:40.960" LastActivityDate="2018-03-10T18:19:40.960" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="13577" PostTypeId="1" CreationDate="2018-03-09T23:01:12.377" Score="8" ViewCount="864" Body="&lt;p&gt;Is it generally understood that we (globally) have been living in an &lt;a href=&quot;https://en.wikipedia.org/wiki/Representative_Concentration_Pathways&quot; rel=&quot;nofollow noreferrer&quot;&gt;RCP8.5&lt;/a&gt; scenario over the past 7-8 years?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Such that a predictive climate model using RCP8.5 assumptions that was run circa 2011 can be considered indicative of the time between then and now?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am working on a calibration of modeled dry-bulb temp data versus real observations over the intervening years but I realize that any correction I come up with would necessarily have any deviation from reality and RCP8.5 baked into it.&lt;/p&gt;&#xA;" OwnerUserId="12405" LastEditorUserId="11908" LastEditDate="2018-03-10T17:19:39.050" LastActivityDate="2018-03-14T01:20:07.797" Title="Are we now and/or have we been in the RCP8.5 scenario?" Tags="|climate-change|temperature|models|climate-models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13578" PostTypeId="1" AcceptedAnswerId="13579" CreationDate="2018-03-10T02:52:32.710" Score="0" ViewCount="238" Body="&lt;p&gt;I was reading in Wikipedia about the &lt;a href=&quot;https://en.wikipedia.org/wiki/Indian_Ocean&quot; rel=&quot;nofollow noreferrer&quot;&gt;Indian Ocean&lt;/a&gt; and I saw there an image of the part of the globe with a &quot;closed sea&quot; (it's marked by a red arrow in the attached picture). What is the name of this sea? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ki4JO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ki4JO.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7190" LastEditorUserId="94" LastEditDate="2018-03-10T07:38:58.863" LastActivityDate="2018-03-10T07:38:58.863" Title="What is the name of the sea in this image?" Tags="|geography|" AnswerCount="1" CommentCount="3" ClosedDate="2018-03-12T14:48:43.117" ContentLicense="CC BY-SA 3.0" />
  <row Id="13579" PostTypeId="2" ParentId="13578" CreationDate="2018-03-10T05:08:27.010" Score="9" Body="&lt;p&gt;That's the &lt;a href=&quot;https://en.wikipedia.org/wiki/Caspian_Sea&quot; rel=&quot;noreferrer&quot;&gt;Caspian sea&lt;/a&gt;, considered the largest enclosed inland body of water on Earth by area. It is bounded by Kazakhstan to the northeast, Russia to the northwest, Azerbaijan to the west, Iran to the south, and Turkmenistan to the southeast.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-03-10T05:08:27.010" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13580" PostTypeId="2" ParentId="13577" CreationDate="2018-03-10T17:17:17.580" Score="7" Body="&lt;p&gt;In short, I would say that it is too soon to say. But, if I were forced to guess: I would indeed incline to say that we live in a RCP 8.5-ish scenario.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not an expert at all on climate models or RCP scenarios, but I found the question interesting, so this is my attempt to answer it based on the most reliable data sources I found. I hope to motivate expert to jump in to comment, improve, challenge or support this answer.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;RCP scenarios&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The scenarios involve future pathways in the emissions of a large range of different chemicals (Greenhouse gases and aerosols), so if we look at how actual emissions of $CO_2$ have matched the scenario we might think we are in one scenario, but is we instead look at the emissions of $NH_3$ we might find ourselves in another scenario. The best way to summarise all those different parameters is to consider the total radiative forcing, that is the combined effect of all those compounds in Earth's energy balance. In fact the numbers that label the different &lt;a href=&quot;https://en.wikipedia.org/wiki/Representative_Concentration_Pathways&quot; rel=&quot;nofollow noreferrer&quot;&gt;RCP&lt;/a&gt;'s are the expected total radiative forcing by year 2100 in $W/m^2$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following figure shows the radiative forcing (this time as $CO_2$ equivalent) of each scenario. And as you can see, by 2018, the differences are so small that I think it is too soon to say with any reasonable certainty that we are flowing one or another scenario.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ySHut.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ySHut.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;(Figure from Wikipedia commons originally &lt;a href=&quot;https://en.wikipedia.org/wiki/Representative_Concentration_Pathways#/media/File:All_forcing_agents_CO2_equivalent_concentration.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Scenarios versus measurements&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Nevertheless, we can attempt to plot the actual measurements against what was predicted  by the scenarios. The best variable to contrast would arguably be the total radiative forcing. However, that is a quantity difficult to calculate and I haven't found published values like those in the &lt;a href=&quot;https://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_AnnexII_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC Assesment report 5 (AR5) Annex II&lt;/a&gt; table AII.1.2, beyond 2011. Up to that year, the forcings were beautifully summarized in figure 8.18 of &lt;a href=&quot;https://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter08_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;AR5 chapter 8&lt;/a&gt;:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/9WIVt.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9WIVt.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given the lack of total radiative forcing data, we can instead make the comparison with some other variable. Such analysis will be liable to depend on the chosen variable as pointed out before. Therefore, to minimize that problem let's pick a variable with a large influence in the difference between the four scenarios. I think that would be $CO_2$ emissions from fossil fuels and industry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The the emissions predicted by each scenario can be obtained at the &lt;a href=&quot;https://tntcat.iiasa.ac.at/RcpDb/dsd?Action=htmlpage&amp;amp;page=compare&quot; rel=&quot;nofollow noreferrer&quot;&gt;RCP Database (version 2.0)&lt;/a&gt;. That data looks like this:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/lMrPN.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lMrPN.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, for the actual estimated emissions, perhaps a reliable source is the &lt;a href=&quot;http://www.globalcarbonproject.org/carbonbudget/17/data.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Carbon Project&lt;/a&gt;, that provide the &lt;a href=&quot;https://data.icos-cp.eu/licence_accept?ids=%5B%22-OrQ3afxxWEwG-LMJDyfVRot%22%5D&quot; rel=&quot;nofollow noreferrer&quot;&gt;emissions data up to 2016&lt;/a&gt;. Putting all that together we get the following figure:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/RQIk6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RQIk6.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, it looks RCP8.5-ish, but the differences between the scenarios are still quite small, so it is difficult to say.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another good variable to compare would be $CO_2$ concentration, that can be directly measured instead of just estimated. In that case using NOAA's &lt;a href=&quot;https://www.esrl.noaa.gov/gmd/ccgg/trends/gl_data.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Greenhouse Gas Reference Network data&lt;/a&gt; for global $CO_2$ concentration, against the ones prescribed for each scenario (taken as well from &lt;a href=&quot;https://tntcat.iiasa.ac.at/RcpDb/dsd?Action=htmlpage&amp;amp;page=compare&quot; rel=&quot;nofollow noreferrer&quot;&gt;RCP Database (version 2.0)&lt;/a&gt;) the figure looks like this&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ynXTd.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ynXTd.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That looks more like RCP4.5-ish. But again, probably too soon to say.&#xA;Also, it might be that even given more time, the path followed by the climate system would be like one RCP in some aspects and like other RCP in other aspect. For example, $CO_2$ emissions might follow roughly RCP8.4 but methane emission might follow RCP4.5. Or somewhere in between.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another approach would be to use use an actual climate model forced by RCP8.5 (not just the RCP), so you can compare mean surface temperature, but that would be tricky for many reasons and also model dependent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If anybody knows of published estimated total radiative forcing from 2012 onward, that would be nice to add and compare. It might make the answer a bit more clear but I think that in any case, it is too soon to give a definite answer.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-14T01:20:07.797" LastActivityDate="2018-03-14T01:20:07.797" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13581" PostTypeId="1" CreationDate="2018-03-10T22:17:18.137" Score="7" ViewCount="1789" Body="&lt;p&gt;I'm trying to gain a firmer conceptual understanding of how redox buffers work in petrology, specifically how oxygen fugacity influences mineral crystallization. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;While I understand the mathematical and thermodynamic principles underlying these concepts, I'm not seeing how changes in the partial pressure (fugacity) of an element such as oxygen can impact what minerals crystallize.&lt;/p&gt;&#xA;" OwnerUserId="12410" LastEditorUserId="725" LastEditDate="2018-03-11T06:59:34.700" LastActivityDate="2018-03-11T07:23:26.383" Title="Please help in understanding redox buffers" Tags="|geochemistry|petrology|thermodynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13582" PostTypeId="2" ParentId="13581" CreationDate="2018-03-11T07:23:26.383" Score="5" Body="&lt;p&gt;First let me start by saying that redox buffers are a made-up thing. All these QFM (actually FMQ) or NNO or other abbreviations don't exist in nature. They were developed as a way to &quot;cheat&quot; in experiments to get the desired Fe(II)/Fe(III) ratio, and later extended for more uses. High temperature and pressure experiments are permeable to hydrogen: it just goes through the experimental capsule. Depending on the direction of diffusion, it can either oxidise or reduce the contents of the capsule, changing the desired Fe(II)/Fe(III) ratio. Buffers &quot;force&quot; a certain oxygen fugacity. In reality, redox (or not) is buffered by a variety of reactions that we may not even know exist.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;partial pressure (fugacity) of an element such as oxygen &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In the deep Earth, there is no free O&lt;sub&gt;2&lt;/sub&gt; gas phase, so it doesn't make sense anymore to talk about the &quot;partial pressure&quot;. But the oxygen fugacity controls the reactions involved electron transfer (i.e. buffers).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;how oxygen fugacity influences mineral crystallization&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In general, higher oxygen fugacity means there's a higher ratio of Fe&lt;sup&gt;3+&lt;/sup&gt; to Fe&lt;sup&gt;2+&lt;/sup&gt;. This is particularly true in melts. So a melt with lots of Fe&lt;sup&gt;3+&lt;/sup&gt; will crystallise magnetite (for example) whereas a reduced melt with little Fe&lt;sup&gt;3+&lt;/sup&gt; will not. This is one of the differences between tholeiitic and calc-alkaline differentiation trends. Calc-alkaline melts are oxidised, so they crystallise magnetite early. Therefore, they never reach high Fe contents. Tholeiitic melts re reduced, and magnetite does not crystallise until very late, so it is possible for them to reach high Fe contents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is also important for sulfur. Will a volcano erupt SO&lt;sub&gt;2&lt;/sub&gt; or H&lt;sub&gt;2&lt;/sub&gt;S? It all depends on the oxygen fugacity of the system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will also add that the bulk amount of Fe&lt;sup&gt;3+&lt;/sup&gt; and Fe&lt;sup&gt;2+&lt;/sup&gt; does not directly tell you where a rock is oxidised or not (with respect to oxygen fugacity). For example, a rock with 1% hematite, 98% enstatite and 1% magnetite will have more bulk Fe&lt;sup&gt;2+&lt;/sup&gt; than a rock with 50% magnetite, 49% quartz and 1% fayalite. But, the former is at the HM buffer while the latter is at the FMQ buffer (reduced).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I highly recommend reading this (preferably more than once):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Frost, B. R. (1991). &quot;Introduction to oxygen fugacity and its petrologic importance.&quot; Reviews in Mineralogy and Geochemistry 25: 1-10.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-03-11T07:23:26.383" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13583" PostTypeId="1" CreationDate="2018-03-11T18:04:11.587" Score="5" ViewCount="605" Body="&lt;p&gt;It's a well known fact that wind will cause very big waves if blowing against a strong current, for example in the gulf stream off the US coast, or in the bay of San Francisco with a very strong (5 knots+) tidal current.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Notably, a 30 knots wind against a 3 knots current will create way bigger waves than a 33 knots wind against no current at all, even-though the relative speeds are obviously the same.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the explanation of this phenomenon?&lt;/p&gt;&#xA;" OwnerUserId="12262" LastEditorUserId="11908" LastEditDate="2018-04-06T19:41:24.903" LastActivityDate="2018-04-07T17:00:44.767" Title="Why does wind blowing against a strong current create way bigger waves?" Tags="|wind|ocean-currents|waves|wave-modeling|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="13584" PostTypeId="1" AcceptedAnswerId="13585" CreationDate="2018-03-11T22:27:45.213" Score="4" ViewCount="534" Body="&lt;p&gt;I'm downloading .grib files from NCEP: &lt;a href=&quot;ftp://nomads.ncdc.noaa.gov/GFS/analysis_only/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ftp://nomads.ncdc.noaa.gov/GFS/analysis_only/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each file has 315 bands. What are their names?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reproducibility with R:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;library(stars)&#xA;library(cptcity)&#xA;met &amp;lt;- read_stars(&quot;ftp://nomads.ncdc.noaa.gov/GFS/analysis_only/201501/20150103/gfsanl_3_20150103_0000_000.grb&quot;)&#xA;met2 &amp;lt;- filter(met, band == 2)&#xA;plot(met2, col = cpt())&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EgVuy.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EgVuy.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6489" LastEditorUserId="94" LastEditDate="2018-03-11T22:34:16.210" LastActivityDate="2018-03-12T12:10:06.753" Title="What are the band names of the NCEP grib files?" Tags="|meteorology|atmosphere|ncep|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13585" PostTypeId="2" ParentId="13584" CreationDate="2018-03-12T06:15:14.473" Score="5" Body="&lt;p&gt;This file is in GRIB-1 format. Each band corresponds to a GRIB message. The band names can be found in an INV file on the same server.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For your example check out the corresponding inv file &lt;code&gt;ftp://nomads.ncdc.noaa.gov/GFS/analysis_only/201501/20150103/gfsanl_3_20150103_0000_000.inv&lt;/code&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another option is to use &lt;code&gt;wgrib -v&lt;/code&gt; with &lt;code&gt;-v&lt;/code&gt;  option.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The band names and offsets for all 315 bands can be obtained this way, e.g. for band 2 &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;2:81534:D=2015010300:VGRD:planetary boundary layer (from Richardson no.)&#xA; :kpds=34,220,0:anl:winds are N/S:&quot;v wind [m/s]&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;That is bands 1 and 2 store &lt;code&gt;u&lt;/code&gt; and &lt;code&gt;v&lt;/code&gt; components of the wind speed at the boundary layer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;code&gt;kpds&lt;/code&gt; parameters make up the product definition section identifiers. The first kpds number can be mapped to mnemonic GRIB identifiers, i.e. number &lt;code&gt;34&lt;/code&gt; maps to &lt;code&gt;VGRD&lt;/code&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The unit is &lt;code&gt;m/s&lt;/code&gt; and the data representation is 64-bit floating point. The latter piece of metadata can be extracted from the GRIB file itself e.g. using &lt;code&gt;gdalinfo&lt;/code&gt;.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Band 2 Block=360x1 Type=Float64, ColorInterp=Undefined&#xA;  Description = 0[-] var220 (reserved)&#xA;  Metadata:&#xA;    GRIB_COMMENT=v-component of wind [m/s]&#xA;    GRIB_ELEMENT=VGRD&#xA;    GRIB_FORECAST_SECONDS=0 sec&#xA;    GRIB_REF_TIME=  1420243200 sec UTC&#xA;    GRIB_SHORT_NAME=0-var220&#xA;    GRIB_UNIT=[m/s]&#xA;    GRIB_VALID_TIME=  1420243200 sec UTC&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;With the &lt;code&gt;-V&lt;/code&gt; option &lt;code&gt;wgrid&lt;/code&gt; utility produces a more detailed output:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;rec 2:81534:date 2015010300 VGRD kpds5=34 kpds6=220 kpds7=0 &#xA;    levels=(0,0) grid=3 planetary boundary layer (from Richardson no.) anl:&#xA;  VGRD=v wind [m/s]&#xA;  timerange 10 P1 0 P2 0 TimeU 1  nx 360 ny 181 GDS grid 0 num_in_ave 0 missing 0&#xA;  center 7 subcenter 0 process 81 Table 2 scan: WE:NS winds(N/S) &#xA;  latlon: lat  90.000000 to -90.000000 by 1.000000  nxny 65160&#xA;          long 0.000000 to -1.000000 by 1.000000, &#xA;          (360 x 181) scan 0 mode 128 bdsgrid 1&#xA;  min/max data -38.8 45.4  num bits 10  BDS_Ref -388  DecScale 1 BinScale 0&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="2511" LastEditorUserId="2511" LastEditDate="2018-03-12T12:10:06.753" LastActivityDate="2018-03-12T12:10:06.753" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13586" PostTypeId="2" ParentId="12605" CreationDate="2018-03-12T12:24:18.600" Score="1" Body="&lt;p&gt;Precipitation can be formed by the heterogeneous nucleation by adding little amount of sample which we want to precipitate. Also term precipitate depends on pH, temperature and concentration. by varying the variable parameter one can easily precipitate out the respective phases.&lt;/p&gt;&#xA;" OwnerUserId="12415" LastActivityDate="2018-03-12T12:24:18.600" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13588" PostTypeId="2" ParentId="12605" CreationDate="2018-03-12T14:47:56.897" Score="2" Body="&lt;p&gt;A very important factor is fluid pressure. The capacity of a fluid to hold dissolved minerals is changing with pressure (usually it increases with increasing pressure).&#xA;Examples (from nice-to-know to significant):&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;A bottle of carbonated water: You open the lid, the pressure drops, degassing occurs.&lt;/li&gt;&#xA;&lt;li&gt;In the formation of stalactites: Water leaves the pressureized ground water aquifer, enters a cavity and precipitates minerals that make the stalactites (ok, other things go on, too, see answer above).&lt;/li&gt;&#xA;&lt;li&gt;Veins: A rock fractures (maybe due to tectonic stress), void is generated, fluid pressure drops, mineral (often quartz or calcite) precipitates as veins. Studying veins tells us something about the (paleo)(tectonic) stress regimes that acted while the veins formed. Super nice to unravel the evolution of a fault or the generation of a mountain chain.&lt;/li&gt;&#xA;&lt;li&gt;Look for &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonate_compensation_depth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Carbonate-Compensation-Depth&lt;/a&gt;. It is like an orographic snow-line but under water. Defined by the pressure of depth, calcite will either precipitate or dissolve into the ocean. &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="6152" LastActivityDate="2018-03-12T14:47:56.897" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13589" PostTypeId="2" ParentId="73" CreationDate="2018-03-12T20:25:08.030" Score="4" Body="&lt;h1&gt;Yes.&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;In addition to triggering natural earthquakes, (as pointed out by @hichris123) Mines can also be sources of artificial seismic activities due to mine collapses and/or explosives.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Miners will generally try their best to keep their mine shaft stable, but their methods aren't 100% accurate. Sometimes mining in an unstable area or with the lack of support to a mine will cause the shaft to collapse, killing anyone still in it. When this happens, there can be a chance that an earthquake could be felt from a nearby town or city.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;Are earthquakes more common in mining regions than they would otherwise be?&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;While there can be earthquakes in mining regions due to other reasons, &lt;strong&gt;yes, they are.&lt;/strong&gt; When a mine collapses, the releasing of the rocks can be so abrupt that &lt;strong&gt;kinetic energy is discharged in the form of a low-magnitude earthquake.&lt;/strong&gt; This is also known as a form of &lt;a href=&quot;https://earthquake.usgs.gov/research/induced/&quot; rel=&quot;nofollow noreferrer&quot;&gt;induced seismicity&lt;/a&gt;, and earthquakes resulting from induced seismicity generally aren't that serious. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you google 'earthquakes due to mining', the following blurb will appear:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The six miners and three rescuers that were killed in the magnitude-3.9 earthquake due to the collapse of the Crandall Coal mine are now memorialized at the site. ... The abrupt release of elastic strain in the rocks during a mine collapse discharges energy in the form of seismic waves.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So this is a good example of induced seismicity.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;e.g. is the frequency of earthquakes in those regions different when mining is occurring than when it is not?&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Since you mentioned mining regions, it will be assumed that a collapsing mine would be more of a common occurrence in a mining region than anywhere else. &lt;strong&gt;So yes,&lt;/strong&gt; the difference would be that there are more seismic waves creating earthquakes in a mining region compared to you're average city, because less mining is occurring in a city that in a mountain. But when no mining is in progress an a mining region, there will be less human-induced earthquakes.&lt;/p&gt;&#xA;" OwnerUserId="12057" LastEditorUserId="12057" LastEditDate="2018-03-12T20:56:54.297" LastActivityDate="2018-03-12T20:56:54.297" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13590" PostTypeId="1" CreationDate="2018-03-13T01:05:06.620" Score="9" ViewCount="276" Body="&lt;p&gt;The Earth is emitting about 47 terawatts of heat energy, producing a heat flow of 0.0921 W/m$^2$ due to radiogenic and primordial heat energy. The heat flow drives mantle convection which in turn drives plate movement. The radiogenic energy declines as the radioisotopes decay and the primordial energy is not replenished; presumably the sum can be approximated as roughly a power-law $\sim (t-t_0)^{-\alpha}$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At what heat flow will mantle convection become too weak to maintain plate movement and Earth will shift to a stagnant lid mode? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am interested in estimating the threshold heat flow needed to maintain plate tectonics on an Earthlike world. So we can ignore the sun going red giant in 5-6 Gyr. Another complicating factor is of course water &quot;lubrication&quot; which might change the threshold, presumably reducing it based on past subduction. But for my purposes (an astrobiological argument) a rough estimate is good enough if it can be supported. &lt;/p&gt;&#xA;" OwnerUserId="12421" LastActivityDate="2018-03-13T01:05:06.620" Title="How much heat flow is needed to maintain plate tectonics?" Tags="|plate-tectonics|earth-history|geothermal-heat|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13591" PostTypeId="1" CreationDate="2018-03-13T02:40:27.363" Score="5" ViewCount="33881" Body="&lt;p&gt;In the Bond movie &quot;Spectre&quot;, there is a scene with a large meteorite on a stand:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/o6wDz.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/o6wDz.jpg&quot; alt=&quot;Karenhoff meteorite&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is this meteorite real, or is it based on a real meteorite? Are there actually any meteorites this large and perfect?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="2491" LastEditorUserId="11908" LastEditDate="2018-03-13T16:43:43.280" LastActivityDate="2018-03-13T17:41:28.053" Title="Is the &quot;Kartenhoff&quot; meteorite real?" Tags="|meteorite|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13592" PostTypeId="1" CreationDate="2018-03-13T04:58:49.373" Score="5" ViewCount="183" Body="&lt;p&gt;&lt;strong&gt;Part 1&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In &lt;a href=&quot;https://journals.ametsoc.org/doi/abs/10.1175/JPO-D-11-0139.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; paper the authors calculate the barotropic stream function from an output of a numerical model as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\psi(x,y)=\int_0^y\int_{-H}^0u(x,y',z)~dz~dy'$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;over a global domain and this is the result:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DxQZY.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DxQZY.png&quot; alt=&quot;streamf&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the caption, they specify that the value at the African continent was subtracted from the result of the integral.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I interpret correctly, this is necessary because the domain is periodic and we need to ensure that the integral over the globe (excluded the Southern Ocean) is zero. Is this correct?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If yes, what is the rationale for choosing the values at the African coast? wouldn't the value at Cape Horn be more natural? &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Part 2&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another aspect of this calculation that I do not understand is the fact that the values of $\psi$ near the coasts are not zero. I would expect the values of the stream function to be zero near the coast in order to ensure a zero transport across the coast. Why is this not an issue?&lt;/p&gt;&#xA;" OwnerUserId="6001" LastEditorUserId="12057" LastEditDate="2018-03-14T18:15:30.943" LastActivityDate="2018-03-14T18:15:30.943" Title="Stream function on a periodic domain?" Tags="|oceanography|ocean-currents|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13593" PostTypeId="2" ParentId="13591" CreationDate="2018-03-13T16:32:11.693" Score="6" Body="&lt;p&gt;The story told in the movie about the meteorite is fictional. Here is a &lt;a href=&quot;http://www.imdb.com/title/tt2379713/quotes&quot; rel=&quot;noreferrer&quot;&gt;quote&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Kartenhoff, the oldest in human possession. The very meteorite&#xA;  which made this crater.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The Kartenhoff is a fictional meteorite (I found few sources about the movie saying so, &lt;a href=&quot;https://www.mi6-hq.com/sections/movies/spectre_trivia&quot; rel=&quot;noreferrer&quot;&gt;this is the most comprehensive one&lt;/a&gt;). It is not the oldest known to humans, and it didn't make the crater shown in the movie. That crater is in fact the &lt;a href=&quot;https://nl.wikipedia.org/wiki/Gara_Medouar&quot; rel=&quot;noreferrer&quot;&gt;Gara Medouar&lt;/a&gt;, a crater-like formation created by erosion NOT a meteorite (&lt;a href=&quot;http://www.dangerousroads.org/africa/morocco/5879-gara-de-medouar.html&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; more info about it). &lt;a href=&quot;https://www.google.nl/maps/place/31%C2%B018&amp;#39;00.0%22N+4%C2%B024&amp;#39;00.0%22W/@31.2893678,-4.4038139,273a,35y,9.75h,75t/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d31.3!4d-4.4?hl=en&quot; rel=&quot;noreferrer&quot;&gt;This link&lt;/a&gt; will take you to a view of it on Google Maps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All the above make me think that the object shown in the movie is not a real meteorite (maybe not even a real object and just crated digitally), however it is definitely inspired in a real one. As it have the color of an &lt;a href=&quot;https://en.wikipedia.org/wiki/Iron_meteorite&quot; rel=&quot;noreferrer&quot;&gt;iron meteorite&lt;/a&gt; and its characteristic &lt;a href=&quot;https://en.wiktionary.org/wiki/regmaglypt&quot; rel=&quot;noreferrer&quot;&gt;regmaglypts&lt;/a&gt; (indentations on the surface of a meteorite created by ablation while falling through the atmosphere). As mention by Trond Hansen in the comments, perhaps ir was inspired by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Willamette_Meteorite&quot; rel=&quot;noreferrer&quot;&gt;Willamette Meteorite&lt;/a&gt;. With 15 ton in weight, it is much larger than the one on the movie (it is 3x2 m) but have a remarkably similar shape and general aspect.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/CPxj4.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CPxj4.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;(Picture from Wikipedia commons, originally &lt;a href=&quot;https://en.wikipedia.org/wiki/Willamette_Meteorite#/media/File:Willamette_Meteorite_AMNH.jpg&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of shape, iron meteorites (that are a small fraction of all existing meteorites), tend to have very irregular shapes. Therefore, to find one as &quot;perfect&quot; as the one in the movie is unlikely, but not imposible. A &lt;a href=&quot;https://www.google.ca/search?q=iron%20meteorite&amp;amp;source=lnms&amp;amp;tbm=isch&amp;amp;sa=X&amp;amp;ved=0ahUKEwjl88-Mz-nZAhVM9WMKHaSGB80Q_AUICigB&amp;amp;biw=2133&amp;amp;bih=1036&quot; rel=&quot;noreferrer&quot;&gt;Google Images search for iron meteorite&lt;/a&gt;, would show you in a glimpse the vast diversity of shapes, been generally irregular.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now when it comes to size, they can be much larger than that. Some examples are the &quot;El Chaco&quot; meteorite found in &lt;a href=&quot;https://en.wikipedia.org/wiki/Campo_del_Cielo&quot; rel=&quot;noreferrer&quot;&gt;Campo del Cielo&lt;/a&gt;, Argentina, weighting 37 ton.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/zjXFs.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zjXFs.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(image taken from &lt;a href=&quot;https://destinoinfinito.com/campo-del-cielo/&quot; rel=&quot;noreferrer&quot;&gt;DESTINO INFINITO&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or the largest iron meteorite know, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hoba_meteorite&quot; rel=&quot;noreferrer&quot;&gt;Hoba meteorite&lt;/a&gt;, with 66 tons.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/dEmOb.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dEmOb.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(image taken from &lt;a href=&quot;https://www.tripadvisor.ca/Attraction_Review-g1137965-d3609771-Reviews-Hoba_Meteorite-Grootfontein_Otjozondjupa_Region.html#photos;aggregationId=101&amp;amp;albumid=101&amp;amp;filter=7&amp;amp;ff=292121881&quot; rel=&quot;noreferrer&quot;&gt;TripAdvisor and submitted by user huys25&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason we found meteorites up to about that size only, is because they are small enough to suffer a significant slow-down when falling though the atmosphere. Larger meteorites hit the surface so fast that the energy released vaporize the meteorite, so only the crater is left with no traces of the impacting body.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-13T17:41:28.053" LastActivityDate="2018-03-13T17:41:28.053" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13594" PostTypeId="5" CreationDate="2018-03-13T16:56:26.517" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2018-03-13T16:56:26.517" LastActivityDate="2018-03-13T16:56:26.517" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13595" PostTypeId="4" CreationDate="2018-03-13T16:56:26.517" Score="0" Body="Questions referring to human activity that causes an earthquake to occur." OwnerUserId="12057" LastEditorUserId="12057" LastEditDate="2018-03-13T23:47:37.460" LastActivityDate="2018-03-13T23:47:37.460" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13596" PostTypeId="1" CreationDate="2018-03-14T06:18:02.947" Score="3" ViewCount="241" Body="&lt;p&gt;Is there anybody who has run WRF-chem with &lt;code&gt;chem_opt=16&lt;/code&gt; successfully to simulate the green house gases? According to the User guide, it can be done in this way. But the detail is vague. Even the &lt;code&gt;auxinput15_inname&lt;/code&gt;, which is the format of input file, could not found explanation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hence, any body can give me advice? If possible, a &lt;code&gt;namelist.input&lt;/code&gt; may be great helpful.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;=============================update 2018.03.22============================&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I still don't konw about the auxinput15.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;BUT, in my case, I use  &lt;code&gt;auxinput5_inname='wrfchemi_d&amp;lt;domain&amp;gt;_&amp;lt;date&amp;gt;'&lt;/code&gt;  for anthropogenic CO2 emission, and the other option about CO2 is set &lt;code&gt;16&lt;/code&gt;.&lt;/p&gt;&#xA;" OwnerUserId="12411" LastEditorUserId="12411" LastEditDate="2018-03-22T11:28:29.167" LastActivityDate="2018-03-22T11:28:29.167" Title="What is the general procedure to run WRF-chem with chen_opt=16" Tags="|climate-change|wrf|wrf-chem|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13598" PostTypeId="1" AcceptedAnswerId="13601" CreationDate="2018-03-14T18:48:24.897" Score="1" ViewCount="1419" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HCgyU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HCgyU.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Trying to understand this image. Can someone tell me if I have the right reasoning here:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Sun has 100% SW shooting to earth&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;30% of that 100% is reflected by clouds&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;70% remains&lt;/li&gt;&#xA;&lt;li&gt;Of that 70%, 45% of that SW is absorbed by Earth's surface.&lt;/li&gt;&#xA;&lt;li&gt;That leaves 25%, where does that go/factored into?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The entire right half of this diagram confuses me, what is happening there? Why is there a red line connecting 70%SW and 70%LW? What does &quot;??%LW&quot; mean?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="12218" LastEditorUserId="11908" LastEditDate="2019-03-11T21:09:55.507" LastActivityDate="2019-03-11T21:09:55.507" Title="Understanding a diagram of Earth's radiation balance" Tags="|atmosphere|climate-change|climate|climate-models|atmospheric-radiation|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13600" PostTypeId="1" CreationDate="2018-03-14T19:03:58.740" Score="3" ViewCount="2345" Body="&lt;p&gt;Looking at two diagrams below, they seem to depict the same system. How are they different? Why one is a radiation balance model and the other a global energy balance model?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;RADIATION BALANCE MODEL:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/mkcGA.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mkcGA.jpg&quot; alt=&quot;RADIATION BALANCE MODEL: &quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;GLOBAL ENERGY BALANCE MODEL:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/l4H0t.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/l4H0t.jpg&quot; alt=&quot;GLOBAL ENERGY BALANCE MODEL: &quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12218" LastEditorUserId="11908" LastEditDate="2019-03-11T20:59:54.707" LastActivityDate="2019-03-11T20:59:54.707" Title="What is the difference between radiation balance and the global energy balance?" Tags="|atmosphere|geophysics|atmospheric-radiation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13601" PostTypeId="2" ParentId="13598" CreationDate="2018-03-14T19:21:46.497" Score="2" Body="&lt;p&gt;LW = Longwave radiation (i.e. Infrared  radiation)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;SW = Shortwave radiation (i.e. Visible + Ultraviolet light)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the left part of the diagram, it shows that the 30% of the total incoming energy (mostly delivered as shortwave radiation) gets reflected by clouds and the Earth's surface. Therefore, 70% is the total absorbed by the planet (45% of it is absorbed by the Surface and 25% by the atmosphere).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The red line refers to the fact that given that Earth energy budget is assumed to be in balance, meaning that the same amount of energy that goes IN the system (as shortwave radiation) must go OUT the system, in the form of longwave radiation, that is the main kind of radiation the Earth emits given its temperature (see &lt;a href=&quot;https://en.wikipedia.org/wiki/Wien%27s_displacement_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wien's law&lt;/a&gt;). This energy balance assumption is a good one, because even if you think that more energy gets IN than OUT, that would lead Earth's temperature to increase, increasing then the amount of emitted energy (according to &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stefan–Boltzmann law&lt;/a&gt;), until it reaches a point where the outgoing radiation released equals the amount received energy from the Sun. Therefore, establishing the energy balance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Due to this balance, the right part of the diagram shows that the same 70% of the energy must be emitted back to space as longwave radiation (the same amount that was absorbed), and for that to be true, it is asking you what would be the required amount of energy that the atmosphere must emit towards Earth as LW radiation to keep the system in balance. Or at least that's my interpretation of the question marks in the absence of further information.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-14T20:28:19.683" LastActivityDate="2018-03-14T20:28:19.683" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13602" PostTypeId="2" ParentId="13600" CreationDate="2018-03-14T20:06:42.830" Score="6" Body="&lt;p&gt;Radiation balance only account for energy transfers trough electromagnetic radiation. Something very useful for the Earth as a whole. As it is the only (or most important by far) way of energy exchange between the Earth and the outer space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Energy balance in the other hand, account for energy transfers trough all possible processes, namely radiation, conduction, sensible heat, latent heat, convection, etc. That are very important to account for the energy transfers within the atmosphere and between it and the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this case your global energy balance includes evaporation and convection (thermals), that are forms of energy exchange not mediated by electromagnetic radiation.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-15T15:35:55.943" LastActivityDate="2018-03-15T15:35:55.943" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13616" PostTypeId="1" CreationDate="2018-03-15T06:03:51.790" Score="1" ViewCount="2426" Body="&lt;p&gt;Was found in central Mexico. It's very metallic, shiny, showing some streaks of gold and quartz.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xbFIw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xbFIw.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12446" LastEditorUserId="12057" LastEditDate="2018-03-15T20:24:56.473" LastActivityDate="2018-03-22T12:01:52.240" Title="Is this platinum ore?" Tags="|rocks|ore|" AnswerCount="1" CommentCount="5" ClosedDate="2019-09-07T00:44:37.317" ContentLicense="CC BY-SA 3.0" />
  <row Id="13617" PostTypeId="1" AcceptedAnswerId="13625" CreationDate="2018-03-15T07:20:48.003" Score="5" ViewCount="2307" Body="&lt;p&gt;Formation of ice and hence more dense saltwater sinking happens in both polar regions, creating downwellings. Meanwhile, only a few spots in Antarctica have upwellings&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I refer to this image:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ZSQOd.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZSQOd.jpg&quot; alt=&quot;Upwelling areas&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Upwelling#/media/File:Upwelling_image1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Upwelling#/media/File:Upwelling_image1.jpg&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12442" LastEditorUserId="111" LastEditDate="2018-03-16T14:20:29.550" LastActivityDate="2018-03-16T14:20:29.550" Title="Why don't Antarctic waters have more upwellings, when Arctic waters are so rich in upwellings?" Tags="|ocean|ocean-currents|antarctic|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="13620" PostTypeId="1" CreationDate="2018-03-15T17:43:39.533" Score="-1" ViewCount="61" Body="&lt;p&gt;Does anyone have absorption coefficients for sulfur dioxide at various wavelengths?&lt;/p&gt;&#xA;" OwnerUserId="12453" LastEditorUserId="94" LastEditDate="2018-03-15T18:29:39.220" LastActivityDate="2018-03-15T18:29:39.220" Title="Does anyone have absorption coefficients at different wavelengths for sulfur dioxide?" Tags="|atmosphere|geophysics|open-data|reference-request|" AnswerCount="1" CommentCount="3" ClosedDate="2018-03-17T04:14:50.890" ContentLicense="CC BY-SA 3.0" />
  <row Id="13621" PostTypeId="2" ParentId="13620" CreationDate="2018-03-15T18:00:36.887" Score="5" Body="&lt;p&gt;The &lt;a href=&quot;https://webbook.nist.gov/cgi/cbook.cgi?ID=C7446095&amp;amp;Type=IR-SPEC&amp;amp;Index=0&quot; rel=&quot;noreferrer&quot;&gt;US National Institute of Standards and Technology&lt;/a&gt; is a good source. The following image show absorbance between 2.5 and 32 $\mu$m. For wavelengths shorter than 2.5 $\mu$m, other sources (less reliable) suggest that there is no significant absorption bands.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/oxOsA.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oxOsA.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;The original data in ASCII JCAMP-DX format can be downloaded &lt;a href=&quot;https://webbook.nist.gov/cgi/cbook.cgi?JCAMP=C7446095&amp;amp;Index=0&amp;amp;Type=IR&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-15T18:05:57.290" LastActivityDate="2018-03-15T18:05:57.290" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13622" PostTypeId="1" AcceptedAnswerId="13623" CreationDate="2018-03-15T18:31:15.273" Score="1" ViewCount="228" Body="&lt;p&gt;The following homework assignment is supposed to be easy, but there seems to be information missing from the questions asked &lt;sub&gt;(or at the very least knowledge from OP)&lt;/sub&gt;.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;At which width circle does the sun shine perpendicularly?&lt;/li&gt;&#xA;&lt;li&gt;How long is a &lt;strong&gt;day&lt;/strong&gt; south of the south polar circle?&lt;/li&gt;&#xA;&lt;li&gt;Which &lt;strong&gt;season&lt;/strong&gt; is starting in the southern hemisphere?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The following picture was included.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/X59Yc.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/X59Yc.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12454" LastEditorUserId="94" LastEditDate="2018-03-16T13:50:24.213" LastActivityDate="2018-03-16T13:50:24.213" Title="Easy homework questions about seasons and daytime" Tags="|homework|sun|seasons|equator|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="13623" PostTypeId="2" ParentId="13622" CreationDate="2018-03-15T20:09:49.707" Score="2" Body="&lt;p&gt;The figure depicts the Northern hemisphere summer solstice, given that, there is no information missing:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;At which width circle does the sun shines perpendicularly?&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The one labeled &quot;13 1/2 uur&quot; that corresponds to the Tropic of Cancer&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;How long is a day south of the southpole circle?&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;If we understand &quot;day&quot; as the length of daytime, the answer is zero: The sun never rises that day south of the southern polar circle.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Which season starts at the southern hemisphere?&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Winter&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-16T12:57:54.243" LastActivityDate="2018-03-16T12:57:54.243" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13625" PostTypeId="2" ParentId="13617" CreationDate="2018-03-15T21:26:18.927" Score="3" Body="&lt;p&gt;First, we might want to distinguish between the different &lt;a href=&quot;https://en.wikipedia.org/wiki/Upwelling#Types&quot; rel=&quot;nofollow noreferrer&quot;&gt;types of upwelling&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Coastal upwelling: It is the best known form of upwelling. Winds in these systems flow parallel to the coast (with the coast to the left in the northern hemisphere or to the right in the southern hemisphere) and generate upwelling dynamics. Surface &lt;a href=&quot;https://en.wikipedia.org/wiki/Ekman_transport&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ekman balance&lt;/a&gt; is setup (in deep enough waters) with water transport being to the right (left) of the wind in the northern (southern) hemisphere. The result is a deficit along the coast that requires a compensating flow in the deeper part of the water column bringing usually colder waters to the surface. If the wind blows in the opposite direction, then &lt;a href=&quot;https://en.wikipedia.org/wiki/Downwelling#Oceanic_downwelling&quot; rel=&quot;nofollow noreferrer&quot;&gt;downwelling&lt;/a&gt; occurs.&#xA;The figure from the question refers to coastal upwelling (&lt;a href=&quot;https://oceanservice.noaa.gov/education/kits/currents/03coastal4.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; in its original website with explaining caption). There is definitely more coastal upwelling in the northern hemisphere because of the abundance of shorelines as a greater amount of landmass is present in that hemisphere. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eihoE.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eihoE.gif&quot; alt=&quot;upwelling animation&quot;&gt;&lt;/a&gt; Source &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Upwelling_animated.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;Commons Wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Equatorial upwelling: Winds from the east blow and converge along the equator as part of the Intertropical Convergence Zone (&lt;a href=&quot;https://en.wikipedia.org/wiki/Intertropical_Convergence_Zone&quot; rel=&quot;nofollow noreferrer&quot;&gt;ITCZ&lt;/a&gt;). While the magnitude of the Coriolis acceleration is zero along the equator, Ekman transport takes place immediately north and south of the equator resulting in surface ocean divergence that requires a compensating flow of denser (nutrient-rich) water upwelled from below.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gsSm6.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gsSm6.gif&quot; alt=&quot;Equatorial upwelling&quot;&gt;&lt;/a&gt; &lt;a href=&quot;http://www-das.uwyo.edu/~geerts/cwx/notes/chap11/equat_upwel.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Southern Ocean upwelling: Strong westerly (eastward) winds dominate the atmospheric setting around Antarctica. The strong winds force the &lt;a href=&quot;https://en.wikipedia.org/wiki/Antarctic_Circumpolar_Current&quot; rel=&quot;nofollow noreferrer&quot;&gt;Antarctic Circumpolar Current&lt;/a&gt;, the strongest current in the ocean. The winds also result in an Ekman balance with northward flow in the upper part of the water column. To compensate that flow, some water flows up from greater depths. The magnitude of the Southern Ocean upwelling is still being studied, but some observations and models propose that it represents the main way for dense water from deeper areas to be reintroduced in the surface circulation. If that were the case, then it represents the largest upwelling system in the world. An alternative explanation proposes &lt;a href=&quot;https://en.wikipedia.org/wiki/Eddy_(fluid_dynamics)#Mesoscale_ocean_eddies&quot; rel=&quot;nofollow noreferrer&quot;&gt;oceanic eddies&lt;/a&gt; as the main mechanism for dense water to reconnect with the surface circulation. Additionally, there is coastal upwelling over the Antarctic continental shelf driven by local winds that brings relatively warmer waters to the shelf contributing to local/regional ice melting.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/8fqNQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8fqNQ.jpg&quot; alt=&quot;southern ocean upwelling&quot;&gt;&lt;/a&gt; &lt;a href=&quot;https://www.nap.edu/read/13169/chapter/1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The question also mentions downwelling associated with dense water formation. Deep water forms at high latitudes (typically north and south of 60°) in both the southern and northern hemispheres. As mentioned in the question, ice contains almost no salt, so when ice forms, a salty, sub-zero brine is left behind and sinks. In the Antarctic, as the saltier water moves down, it mixes with slightly warmer intermediate water. The mixture becomes &lt;a href=&quot;https://en.wikipedia.org/wiki/Antarctic_bottom_water#Formation_and_circulation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Antarctic Bottom Water&lt;/a&gt; (AABW), which flows northwards along the bottom in all the main oceans. In the Arctic, the northward flowing branch of the Gulf Stream (salty and warm) joins the subpolar gyre and enters the Labrador Sea where as it cools, it starts to sink. The eastern branch of the Gulf Stream begins to sink in the Nordic Seas. The resulting water masses combine to form the dense &lt;a href=&quot;https://en.wikipedia.org/wiki/North_Atlantic_Deep_Water&quot; rel=&quot;nofollow noreferrer&quot;&gt;North Atlantic Deep Water&lt;/a&gt; (NADW) that flows south at depth. Both the creation of AABW and NADW can be considered downwelling, as there is a net downward flow in the formation areas, but they are not related to wind-driven downwelling in the vicinity of coasts.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2018-03-15T21:26:18.927" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13626" PostTypeId="1" AcceptedAnswerId="13628" CreationDate="2018-03-16T00:09:01.223" Score="9" ViewCount="536" Body="&lt;p&gt;Was discussing the terrain and rivers of Europe today with my father and it became apparent that a graph of the elevation versus course of a river would offer interesting insight, including a quick summary into the elevation of various cities of interest along the course, and some loose feel for the possible speed of the river in various spots.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I did find one image fitting the general theme of what I was looking for regarding the upper Mississippi River at &lt;a href=&quot;http://rivergages.mvr.usace.army.mil/WaterControl/Districts/MVP/Reports/projects/profiles/index.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;an Army Corp of Engineer's website&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qUC7H.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qUC7H.png&quot; alt=&quot;Upper_MS_Height&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I didn't have any subsequent luck in Googling the terms used there, nor on any additional terms, for rivers like the Rhine and Danube.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are these along-course cross-sections made enough that there's a name for them?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And if so, is there any resource where such images can readily be found for major rivers worldwide?&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="10681" LastEditDate="2018-09-28T12:49:27.370" LastActivityDate="2018-09-28T12:49:27.370" Title="Is there a special name for along-course elevation profiles of rivers, and where you can you find them?" Tags="|hydrology|geography|rivers|reference-request|topography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13627" PostTypeId="2" ParentId="10025" CreationDate="2018-03-16T00:51:32.410" Score="3" Body="&lt;p&gt;As you have multiple nearby gauge stations. I would suggest to compute a multiple linear regression that would allow you to estimate the rain in one station using the data from the others.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then, compute the historical standard  deviation of the measurements in that station relative to the prediction using the linear regression model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With this, you can filter data errors by rejecting all points that deviate more than X standard deviations from the prediction based on nearby stations. You have to define your threshold X based on experience, and by looking at the data. It will depend in the quality of the correlation between the precipitation in the different stations, so no universal value can be defined.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-03-16T00:51:32.410" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13628" PostTypeId="2" ParentId="13626" CreationDate="2018-03-16T01:12:20.933" Score="11" Body="&lt;p&gt;I guess there are multiple names, but I know it as the river's &quot;&lt;a href=&quot;https://geographyas.info/rivers/long-and-cross-profiles/&quot; rel=&quot;noreferrer&quot;&gt;long profile&lt;/a&gt;&quot;, and it is used in academic papers (&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0169555X06002303&quot; rel=&quot;noreferrer&quot;&gt;one example here&lt;/a&gt; and a &lt;a href=&quot;https://scholar.google.ca/scholar?hl=en&amp;amp;as_sdt=0%2C5&amp;amp;as_vis=1&amp;amp;q=long%20profiles&amp;amp;btnG=&quot; rel=&quot;noreferrer&quot;&gt;search in google scholar here&lt;/a&gt;). But you can find similar diagrams under names like the river's height profile, longitudinal profile, longitudinal map or geographic profile. These last two are the ones used in an Australian government &lt;a href=&quot;https://www.mdba.gov.au/publications/mdba-reports/geographic-profile-maps-basin-catchments&quot; rel=&quot;noreferrer&quot;&gt;web page that have many of those profiles&lt;/a&gt; for all major rivers in Australia, with the cities along the river and other information. I'm not aware of a global repository of long profiles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following picture is from the same link pointed above (from &lt;a href=&quot;https://geographyas.info/rivers/long-and-cross-profiles/&quot; rel=&quot;noreferrer&quot;&gt;Geography AS Notes&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5fNrG.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5fNrG.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A quick search for &quot;Danube long profile&quot; put the following image in the second position of the results&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Lg2Bl.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Lg2Bl.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Taken from &lt;a href=&quot;http://www.vvb.sk/old.gabcikovo.gov.sk/doc/Env&amp;amp;riv/text.htm&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-04-19T15:12:46.853" LastActivityDate="2018-04-19T15:12:46.853" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13630" PostTypeId="2" ParentId="13473" CreationDate="2018-03-16T11:48:57.317" Score="5" Body="&lt;p&gt;I'll attempt some answer, but must admit it's a bit speculative. I think, like with many unusual/rare phenomena, there's a fair bit of observational bias and of psychology involved as well.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Mechanism&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;I remember reading about this in at least two popular meteorological publications, one book about extreme and strange weather and an article in (I think) in &quot;Weather&quot;, the journal of the UK Meteorological Society. Unfortunately I don't have the precise source and have to work from memory. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My impression was that it's generally accepted that tornadoes and similar phenomena, which are known to lift and carry water and debris, can in principle sometimes pick up small animals as well, which then might fall at a certain distance when the tornado dissolves. &lt;a href=&quot;https://phys.org/news/2013-03-tornado-debris.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;One study&lt;/a&gt; shows that small items can be carried up to 355km far in tornadoes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The tornado doesn't just stop suddenly, but gets weaker, so debris and possible animals wouldn't all fall at the same time like a huge swarm, but a few at a time in different locations, and it would only happen in rare circumstances.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Observations&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;There are also - as you also found - many historical reports. Many are collected by Forteans (going back to Charles Fort, who dedicated his life to collecting unusual observations), but are of varying quality, usually from casual observers, not scientists. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With such casual reports of unusual observations, often from newspaper and second/third hand, you have to consider that the story changes as it's told and may not be reported exactly as it happened. So, 2 or 3 fishes may become a whole swarm, and it may be reported that people saw them falling when in fact they just found some dead fish on dry ground and couldn't immediately work out where they came from.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That there are various effects that change peoples' perception of unsual phenomena, and how they are subsequently reported, is better established for other, more frequent sightings like ghosts or UFOs, and of course eyewitness reports of crimes, where there is huge body of psychological research. Basically, what people report (and sincerely believe to be a true observation) is often not exactly what happened, and media reports are even less reliable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, in some instances the &quot;falling from the sky&quot; may not actually be observed but an an explanation that people came up with after finding the animals. There are other reasons why aquatic animals can occur on land sometimes in large numbers. Frogs and toads migrate at spawning time in huge numbers, and also toads come out of the ground after a rain. Large number of fish can end up on dry ground when a river floods and recedes. I've seen it myself as a child when visiting relatives in the countryside that a field was full of dead fish and wondered where they had come from, but my relatives told me the area had been flooded at spring melt. It was not at all obvious to me that a rather small stream could flood so much, so I can well imagine that somebody might conclude that they must have fallen from the sky. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So it's not so easy to establish how frequently it really happens that animals fall from the sky. While (unlike ghosts) it's not scientifically impossible and a credible mechanism (tornadoes) exists, it's rare enough that we don't have really good, comprehensive observations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now for your questions:&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Why one type of animal?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;It seems generally fish and frogs. I think there are two reasons, one meteorological and one psychological. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A tornado has to pick up the animals in the first place. These would be have to be small animals. Now, the density of fish and frogs in a pond is often very high, so if a tornado moves over a pond or lake sucks up water, there is a chance that it would lift hundreds or thousands of fish or frogs, so it is much more likely, when thy fall, that they are seen or found.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Small land animals, like mice, tend not to live in such dense populations, and also run away or bury themselves in the ground. So while some will certainly be sucked up in a tornadoe, it's much less likely and probably not many.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second factor is psychological. Many observations are not actually of the animal falling down, but of animals lying on the ground that shouldn't be there. So, if there's a fish or frog lying in dry ground after a weather event, people would notice and report it. If they find a dead mouse, they wouldn't find it unusual and forget about it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, mice are good at falling from height, so they may survive and just run away and never be seen, whereas a fish on land will just die and start to stink after a while (and therefore be noticed...).&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Why no videos?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;There's an observational problem here. Ideally a scientist would like to observe first the animals being sucked up, and then falling. Now, tornadoes are not that easy to observe at close range, so observing animals being sucked in is technically very difficult. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Observing when the animals fall is in principle possible, but probably extremely unlikely. First of all, the event itself is unlikely (see above). Then, when it happens, more frequently it's probably just one fish suddenly coming down unexpectedly, not a longer &quot;rain&quot; of fish. So unless you were already filming for some other reason and catch it by chance, you wouldn't have time to get out the camera and actually film it falling. &lt;/p&gt;&#xA;" OwnerUserId="3163" LastEditorUserId="3163" LastEditDate="2018-03-17T12:52:05.810" LastActivityDate="2018-03-17T12:52:05.810" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13632" PostTypeId="2" ParentId="13473" CreationDate="2018-03-16T13:30:58.617" Score="5" Body="&lt;p&gt;Brian Dunning already went into this extensively in episode 4170 of Skeptoid: &lt;a href=&quot;https://skeptoid.com/episodes/4170&quot; rel=&quot;noreferrer&quot;&gt;It's Raining Frogs and Fish &lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In 1901, a rainstorm in Minneapolis, MN produced frogs to a depth of several inches, so that travel was said to be impossible. Fish famously fell from the sky in Singapore in 1861, and again over a century later in Ipswich, Australia in 1989. Residents in southern Greece awoke one morning in 1981 to find that a shower of frogs had blanketed their village. Golfers in Bournemouth, England found herring all over their course after a light shower in 1948. In 1901, a huge rainstorm doused Tiller's Ferry, SC, and covered it with catfish as well as water, to the point that fish were found swimming between the rows of a cotton field. In 1953, Leicester, MA was hit with a downpour of frogs and toads of all sorts, even choking the rain gutters on the roofs of houses. The stories go on and on: More frogs in Missouri in 1873 and Sheffield, England in 1995, and more fish in Alabama in 1956.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;From everything he read, waterspouts seem unlikely:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Not once in a single case of several dozen that I read was there ever a report of a tornado or waterspout in the vicinity, or even at all, no matter how far away. I conclude that waterspouts have no connection, either hypothetical or evidentiary, to the phenomenon of frogs, fish, or any other animals, falling out of the sky.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;For frogs it seem to be coincidences of bad weather and frog migration.&lt;br /&gt;Well, not really coincidence: they probably migrate more (often) when it's wet.&lt;br /&gt;&#xA;And for fish:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;You don't find mass migrations of fish crossing overland, do you? Well, maybe not mass migrations, but believe it or not, there are fish species that occasionally take to the ground in search of better waters. There are many species of &quot;walking fish&quot; in the world.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The main reason that they did not fall from the sky is simple:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Drop a fish off a building, and that's a dead fish&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That's why you won't find actual videos.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Brian concludes:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Go back and read any story you've ever seen about frogs and fish falling from the sky, this time allowing for the possibility that the animals were already naturally on the ground when the witnesses first discovered them. Allow for the possibility that some elements of the report, like the falling part, could be based originally on witness conjecture or assumption. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Which is more or less what Stephan also writes in his answer.&lt;/p&gt;&#xA;" OwnerUserId="595" LastActivityDate="2018-03-16T13:30:58.617" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13635" PostTypeId="2" ParentId="9674" CreationDate="2018-03-16T20:24:32.500" Score="2" Body="&lt;h1&gt;Millions of years.&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;While it also depends on what kind of rock you're asking about, @GaryKindel's answer above lists a number of other properties a rock has that will effect the time it will take to decompose.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;So do mountains and stones decompose?&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Yes, they do; but very slowly.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Over millions and sometimes billions of years, a rock will decompose into sediment. As stated above, and then again in @GaryKindel's answer, The rate that they will decompose at really depends on the rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example; two types of rocks that will decompose quickly &lt;em&gt;(still being hundreds of thousands of years or more)&lt;/em&gt; are listed below:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://i.stack.imgur.com/06ptP.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/06ptP.jpg&quot; alt=&quot;Sandstone&quot;&gt;&lt;/a&gt;&#xA;&lt;strong&gt;Sandstone&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Hardness: 2&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://i.stack.imgur.com/a0dMG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/a0dMG.png&quot; alt=&quot;Calcite&quot;&gt;&lt;/a&gt;&#xA;&lt;strong&gt;Calcite&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Hardness: 3&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And some rocks that decompose very slowly:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://i.stack.imgur.com/TnU4Z.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TnU4Z.jpg&quot; alt=&quot;Corundum&quot;&gt;&lt;/a&gt;&#xA;&lt;strong&gt;Corundum&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Hardness: 9&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://i.stack.imgur.com/7xZ31.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7xZ31.jpg&quot; alt=&quot;Diamond&quot;&gt;&lt;/a&gt;&#xA;&lt;strong&gt;Diamond&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Hardness: 10&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;What is the life span of a stone?&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Rocks never die, they just change form. So they don't have a lifespan.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rocks are always changing form, but too slowly to notice with you're eyes. In fact; rocks aren't even classified as living things. But all rock goes through three main stages:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Metamorphic&lt;/strong&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Igneous&lt;/strong&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Sedimentary&lt;/strong&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The process these rocks go through is called the &lt;a href=&quot;http://www.ducksters.com/science/rocks.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;rock cycle&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yIMJq.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yIMJq.jpg&quot; alt=&quot;Rock cycle&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are also some substages:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Magma (Lava; molten rock)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Sediment or soil (microscopic rocks we cannot see; sorta like body cells) &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;After it decomposes, what does it turn into?&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Well, more rock. Just in another stage of the rock cycle.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(usually sedimentary)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As mentioned above, rocks are always changing form, and they do go through a number of substages. But after a rock decomposes, it will become sediment, then after a number of years will compress into a form of sedimentary rock &lt;em&gt;(e.g. Sandstone, shale, etc.)&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/a7zTI.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/a7zTI.jpg&quot; alt=&quot;A form of sedimentary rock&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And as @jamesqf mentioned above, some sedimentary rock can be crushed with your bare hands.&lt;/p&gt;&#xA;" OwnerUserId="12057" LastEditorUserId="12057" LastEditDate="2018-03-16T20:56:03.600" LastActivityDate="2018-03-16T20:56:03.600" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13636" PostTypeId="1" AcceptedAnswerId="13642" CreationDate="2018-03-16T21:34:58.137" Score="9" ViewCount="1129" Body="&lt;p&gt;In helping my son with his college biology I ran across some statements that I think are wrong according to updated data.  The copyright is 2017 so it is supposed to reflect the most current knowledge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It makes the following assertion&#xA;&quot;All life on earth gets its energy from the sun&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We know this is not true since extremeophiles that thrive on alternate energy sources were observed in the deep ocean volcanic vents where no sunlight can penetrate and in subterranean environments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact, it is speculated that the subterranean biomass is greater than the familiar surface biomass of the earth.  &lt;strong&gt;What are the most recent estimates of the size of  biomass that does not derive it's energy from the photosynthesis originated food chain?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="8212" LastEditorUserId="11908" LastEditDate="2018-03-18T19:35:19.417" LastActivityDate="2018-03-19T01:03:38.407" Title="Is it true that &quot;All life on earth gets its energy from the sun&quot;? How much biomass is not derived from photosynthesis?" Tags="|biogeochemistry|geobiology|biomass|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13639" PostTypeId="2" ParentId="10025" CreationDate="2018-03-17T20:59:15.370" Score="1" Body="&lt;p&gt;It depends on what you want the info for. If you are designing a dam or drainage system for a 500 years event you better not ignore the high points. I recently measured 40 &quot; in my yard during &quot;Harvey&quot;. This is dramatically more than I measured in any other storm for 20 years but that doesn't mean it didn't happen. &lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2018-03-17T20:59:15.370" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13642" PostTypeId="2" ParentId="13636" CreationDate="2018-03-18T19:33:18.593" Score="8" Body="&lt;p&gt;As you say, the existence of organism that live out of chemical compounds expelled by &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydrothermal_vent&quot; rel=&quot;noreferrer&quot;&gt;hydrothermal vents&lt;/a&gt; (&lt;a href=&quot;https://en.wikipedia.org/wiki/Chemotroph#Chemoautotroph&quot; rel=&quot;noreferrer&quot;&gt;Chemoautotrophs&lt;/a&gt;), immediately render the sentence &quot;&lt;em&gt;All life on earth gets its energy from the sun&lt;/em&gt;&quot; as an approximation. However, some approximations are pretty good for all practical purposes. Nevertheless, this approximation (even if right), have some deep implications when it comes to assess the likelihood of life in other celestial bodies, like Jupiter's moon &lt;a href=&quot;https://en.wikipedia.org/wiki/Europa_(moon)&quot; rel=&quot;noreferrer&quot;&gt;Europa&lt;/a&gt;, which is the kind of concerns through which I got involved into this topic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, there is a very important distinction to make regarding your question,  that is really about&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;biomass that does not derive it's energy from the photosynthesis&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As you describe it. But that's &lt;strong&gt;very&lt;/strong&gt; different than &quot;subterranean biomass&quot;. In particular, the following sentence that you mention:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...it is speculated that the subterranean biomass is greater than the&#xA;  familiar surface biomass of the earth.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Refers to the biomass within soils (i.e. roots, fungus, bacterias, arthropods, etc.), which is indeed very large. You might include deep ocean ecosystems also. But in all those cases, the energy used by organism was originated by photosynthesis and ultimately by the Sun. The energy get to those sub-surface ecosystem in the form of buried dead organic matter or &lt;a href=&quot;https://en.wikipedia.org/wiki/Marine_snow&quot; rel=&quot;noreferrer&quot;&gt;marine snow&lt;/a&gt;. Some works hypothesize about other massive subsurface ecosystems living deep within the oceanic crust, &lt;a href=&quot;https://www.eurekalert.org/pub_releases/2011-06/sicp-etd060211.php&quot; rel=&quot;noreferrer&quot;&gt;hosting perhaps up to 1/2 to 2/3 of the global biomass&lt;/a&gt;. However, as pointed by &lt;a href=&quot;http://www.cen.ulaval.ca/merge/pdf/Whitman1998.pdf&quot; rel=&quot;noreferrer&quot;&gt;Whitman et. al. (1998)&lt;/a&gt; (the source for the above figure): &quot;current evidence suggests that most of the subsurface biomass is supported by organic matter deposited from the surface&quot;. Therefore, it would constitute just one more photosynthetically supported ecosystem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That been said, the core of your question is &lt;em&gt;&quot;What is the size of biomass that does not derive it's energy from photosynthesis?&quot;&lt;/em&gt; And that can be boiled down to: &lt;strong&gt;What is the fraction of global &lt;a href=&quot;https://en.wikipedia.org/wiki/Primary_production&quot; rel=&quot;noreferrer&quot;&gt;net primary production&lt;/a&gt; that come from &lt;a href=&quot;https://en.wikipedia.org/wiki/Chemosynthesis&quot; rel=&quot;noreferrer&quot;&gt;chemosinthesis&lt;/a&gt;?&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know of any estimation of that fraction, but to calculate an &lt;strong&gt;upper limit&lt;/strong&gt; for it should be pretty straight forward, at least to have a sense of how good is the approximation of saying that &quot;all life gets its energy from the sun&quot;, and how important could be chemosynthesis for the global biomass &lt;strong&gt;at most&lt;/strong&gt;. Let's crunch some numbers:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First consider how much energy is there available for chemosynthesis. To do this it is important to note that no organism can get its energy from the energy gradient within the Earth, so the amount of energy available IS NOT the &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_internal_heat_budget&quot; rel=&quot;noreferrer&quot;&gt;Earth's internal heat budget&lt;/a&gt;. Instead, it correspond to the amount of energy available to life in the form of chemical compounds that come from Earth's interior. According to &lt;a href=&quot;http://science.sciencemag.org/content/284/5420/1631.full&quot; rel=&quot;noreferrer&quot;&gt;Gaidos et al.&lt;/a&gt;, in the most active hydrothermal vent fields, it correspond to 0.157 $MJ/m^2 year$ (read as Mega Joules per square meter per year). The same paper point that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;For comparison, the primary production in the upper ocean is&#xA;  equivalent to a biological energy flux of ∼315.36 $MJ/m^2 year$, and this&#xA;  is only 0.01% of the total energy available in sunlight.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, the upper ocean ecosystem is nutrient limited, so the efficiency could be much higher at hydrothermal vents. Perhaps the &lt;a href=&quot;https://en.wikipedia.org/wiki/Primary_production#Primary_Production_and_Plant_Biomass_for_the_Earth&quot; rel=&quot;noreferrer&quot;&gt;most efficient ecosystem is the tropical rain forest&lt;/a&gt;, with efficiencies in the order of the few percent (~1-3%). So as we are looking for an upper limit, let's say that the ecosystem at the hydrothermal vents have an efficiency of 10%. That leaves us with 0.016 $MJ/m^2 year$ to transform to organic matter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now: How much energy is there in a kilogram of organic matter? It varies, but given we are aiming to an upper limit &lt;a href=&quot;https://en.wikipedia.org/wiki/Energy_content_of_biofuel&quot; rel=&quot;noreferrer&quot;&gt;a reasonable (low) typical value is ~10 $MJ/kg$&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We need also to know the surface of hydrothermal vents. To aim again for an upper limit, let's say that all mid-oceanic ridges have the energy availability cited above (referring to the most active hydrothermal vent fields). With &lt;a href=&quot;https://en.wikipedia.org/wiki/Mid-ocean_ridge&quot; rel=&quot;noreferrer&quot;&gt;80,000 km of mid-oceanic ridges and about ~15 km wide&lt;/a&gt;, we have about 1.2$\times 10^{12}$ $m^2$. Keep in mind that looking at the &lt;a href=&quot;https://www.nature.com/articles/nrmicro1991/figures/1&quot; rel=&quot;noreferrer&quot;&gt;global distribution of known hydrothermal vents&lt;/a&gt; in the figure below, this is most likely a massive overestimation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lAFLt.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lAFLt.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Putting all together, our upper limit for the chemosynthetic biomass would be:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\frac{0.016 MJ/m^2 year \times 1.2 \times 10^{12} m^2}{10 MJ/kg}=1.92 \times 10^9 kg/year$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, if we compare that with the &lt;a href=&quot;https://en.wikipedia.org/wiki/Primary_production#Primary_Production_and_Plant_Biomass_for_the_Earth&quot; rel=&quot;noreferrer&quot;&gt;1.7$\times 10^{14} kg/year$ that is produced by photosynthetic primary producers&lt;/a&gt;. &lt;strong&gt;We get that chemosynthesis produce AT MOST a 0.001% of the biomass&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It can be argued that chemosynthesis happens also outside of hydrothermal vents. But those other locations, like geysers and hot springs, are much smaller. Other more extensive chemosynthetic ecosystems have been proposed, like &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0966842X0500199X&quot; rel=&quot;noreferrer&quot;&gt;SLiMEs (Subsurface Lithoautotrophic Microbial Ecosystems)&lt;/a&gt;, but even if they exist over extensive areas, their productivity would be very small.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To summarize, it would be more correct to say that &quot;&lt;strong&gt;More than 99.999% of the life on Earth gets its energy from the Sun&lt;/strong&gt;&quot;. And given all the over estimations we made, I would not be surprised if a more detailed calculation would add a few extra &quot;9's&quot; to that figure.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-19T01:03:38.407" LastActivityDate="2018-03-19T01:03:38.407" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13643" PostTypeId="2" ParentId="9002" CreationDate="2018-03-18T19:56:36.800" Score="2" Body="&lt;p&gt;A very simple answer is that it is related to the demands of the vegetation types and their ability to maximize the net radiation. A &quot;perfect&quot; plant that covered the entire surface would theoretically result in a BR of 0 as 100% of Rn is used for photosynthesis and released as ET, such that H=0 and LE=RN and B=H/L. It obviously doesn't work that way though. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since $B=y\frac{\partial T}{\partial e}$ where y is the psych constant (~0.4 and really not a constant) it can be seen that the gradients of temperature and moisture, not the actual values, are the only two factors that matter in determining the Bowen ratio. Each plant essentially has a &quot;specific Bowen Ratio&quot; range where they are able to maximize their use of RN for the environment they are in. If the climate changes in that area the plant would not be able to survive. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is a very very basic and highly simplified explanation, but hopefully it helps&lt;/p&gt;&#xA;" OwnerUserId="12466" LastEditorUserId="11908" LastEditDate="2018-03-18T20:04:43.960" LastActivityDate="2018-03-18T20:04:43.960" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13644" PostTypeId="1" CreationDate="2018-03-19T01:52:10.823" Score="11" ViewCount="275" Body="&lt;p&gt;There is large amounts of observations supporting the effects of volcanic eruptions on climate: A long term &lt;a href=&quot;https://scied.ucar.edu/shortcontent/how-volcanoes-influence-climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;subtle warming effect due to &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; and a short term, but more intense cooling effect due ash and sulfur gases&lt;/a&gt;.&#xA;There is also much evidence supporting long and dramatic volcano triggered &#xA; cooling events dubbed &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Volcanic_winter&quot; rel=&quot;nofollow noreferrer&quot;&gt;volcanic winters&lt;/a&gt;&quot;, like the one after the &lt;a href=&quot;https://en.wikipedia.org/wiki/1815_eruption_of_Mount_Tambora&quot; rel=&quot;nofollow noreferrer&quot;&gt;1815 eruption of Mount Tambora&lt;/a&gt;, or the &lt;a href=&quot;http://Toba%20catastrophe%20theory&quot; rel=&quot;nofollow noreferrer&quot;&gt;Toba catastrophe&lt;/a&gt; 74,000 years ago, perhaps lasting up to a decade.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For more recent volcanic eruptions, there is evidence of algae blooms produced by the input of nutrients from volcanic eruptions (&lt;a href=&quot;https://www.clisap.de/clisap/about-us/news/volcanic-ash-causes-oceanic-algal-bloom-scientists-of-the-university-of-hamburg-document-iron-fertilization-by-volcanic-ash-2/&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;http://www.sciencemag.org/news/2010/10/how-volcanoes-feed-plankton&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;). Perhaps an expected outcome given that the ecosystems at the surface of the ocean are nutrient limited, therefore wasting most of the available energy due to the lack of iron, nitrogen and phosphorous mainly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For all the above, I would be inclined to think that a large volcanic winter would encompass a period of prosperity for oceanic life. Where a small decrease in solar irradiation is more than compensated by a large increase in nutrients availability. However, I haven't hear of evidence of such oceanic boom.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Are there observations suggesting or disproving such oceanic booms during volcanic winter events?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS: I started pondering this question while thinking about &lt;a href=&quot;http://www.sciencemag.org/news/2018/03/how-ancient-humans-survived-global-volcanic-winter-massive-eruption&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt;, on which they found that a coastal community in South Africa didn't seem to have been affected by the Toba &quot;catastrophe&quot;, but on the contrary, they seem to have benefited from it.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="2470" LastEditDate="2020-01-02T19:12:06.907" LastActivityDate="2020-01-02T19:12:06.907" Title="Would a volcanic winter trigger an oceanic &quot;spring&quot;?" Tags="|oceanography|volcanology|climate-models|paleoclimatology|volcanic-eruption|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="13646" PostTypeId="1" CreationDate="2018-03-19T13:55:53.517" Score="7" ViewCount="1583" Body="&lt;p&gt;It is well known that &lt;a href=&quot;https://www.weather.gov/rah/edu2&quot; rel=&quot;nofollow noreferrer&quot;&gt;temperature sensors are often shaded&lt;/a&gt;, partially to mitigate the variability due to varying cloud cover. However, most people experience temperature within the sunlight. Other measurements of temperature that describe how temperature is felt are the heat index and wind chill, but both neglect the effect of the sun. For example, a very low wind chill can partially be overcome by a clear, sunny day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there such a formula that perhaps gives an upper echelon of experiential temperature? I envision such a formula would involve the solar angle, albedo and perhaps the radiative balance.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="11908" LastEditDate="2018-03-20T17:30:37.880" LastActivityDate="2018-03-20T18:11:15.163" Title="Is there a formula that gives the temperature of an object or person exposed to the sun?" Tags="|temperature|radiative-transfer|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13647" PostTypeId="2" ParentId="13616" CreationDate="2018-03-19T13:55:57.857" Score="3" Body="&lt;p&gt;The rock you have is most likely not platinum ore.  It appears to be sulfide ore most likely composed of galena, pyrite, and maybe copper sulfides such as bornite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is more likely that your specimen is silver ore rather than platinum ore.&#xA;Mexico has a long history of silver mining.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a platinum deposit in southern mexico and it appears to similar to the Bushveld igneous complex deposit.  Ref: &lt;a href=&quot;https://www.mindat.org/loc-132658.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mindat&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Layered chromtite ore looks significantly different.  &lt;a href=&quot;https://www.geologyforinvestors.com/layered-mafic-intrusions-largest-source-platinum-palladium/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reference&lt;/a&gt;.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/bZXna.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bZXna.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://minerals.usgs.gov/minerals/pubs/commodity/platinum/myb1-2012-plati.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS report on Platiunum&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.mining-technology.com/features/feature-the-10-biggest-silver-mines-in-the-world/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Article on current silver mining in Mexico.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="1149" LastEditDate="2018-03-22T12:01:52.240" LastActivityDate="2018-03-22T12:01:52.240" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13649" PostTypeId="2" ParentId="13446" CreationDate="2018-03-19T17:49:51.430" Score="4" Body="&lt;p&gt;Blue River, BC, Canada has an average windspeed of 0.7 m/s (2.6km/h)... &lt;a href=&quot;http://climate.weather.gc.ca/climate_normals/results_1981_2010_e.html?searchType=stnName&amp;amp;txtStationName=blue+river&amp;amp;searchMethod=contains&amp;amp;txtCentralLatMin=0&amp;amp;txtCentralLatSec=0&amp;amp;txtCentralLongMin=0&amp;amp;txtCentralLongSec=0&amp;amp;stnID=1237&amp;amp;dispBack=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://climate.weather.gc.ca/climate_normals/results_1981_2010_e.html?searchType=stnName&amp;amp;txtStationName=blue+river&amp;amp;searchMethod=contains&amp;amp;txtCentralLatMin=0&amp;amp;txtCentralLatSec=0&amp;amp;txtCentralLongMin=0&amp;amp;txtCentralLongSec=0&amp;amp;stnID=1237&amp;amp;dispBack=1&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12470" LastActivityDate="2018-03-19T17:49:51.430" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13654" PostTypeId="1" AcceptedAnswerId="13736" CreationDate="2018-03-20T11:56:27.043" Score="11" ViewCount="8261" Body="&lt;p&gt;Water is a renewable resource, renewed by the water cycle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we use water too quickly, water should get evaporated and come down again as precipitation.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, &lt;strong&gt;Why is there water scarcity if water is a renewable resource?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="11519" LastEditorUserId="11908" LastEditDate="2019-03-11T23:21:32.007" LastActivityDate="2021-01-30T18:24:33.793" Title="If water is a renewable resource, why is there water scarcity?" Tags="|climate-change|hydrology|water|" AnswerCount="7" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13655" PostTypeId="1" AcceptedAnswerId="13656" CreationDate="2018-03-20T14:34:22.500" Score="8" ViewCount="220" Body="&lt;p&gt;I am trying to set up a spectral wave model for waves forecasting in the Mediterranean. I need the meteorological forecast for this region. I am aware of the ECMWF datasets. But unfortunately, only the reanalyses datasets are freely available. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, is there any free source for wind forecasting which covers the Mediterranean region?&lt;/p&gt;&#xA;" OwnerUserId="12479" LastEditorUserId="192" LastEditDate="2018-03-20T15:40:16.213" LastActivityDate="2018-03-20T15:40:16.213" Title="What wind forecast datasets are available for forcing a wave forecast model?" Tags="|wind|weather-forecasting|wave-modeling|mediterranean|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13656" PostTypeId="2" ParentId="13655" CreationDate="2018-03-20T14:49:47.177" Score="8" Body="&lt;p&gt;Yes, the GFS model is a global model. The data is released in the public domain, so you can use it for free for any lawful purpose. See complete terms of use &lt;a href=&quot;https://www.weather.gov/disclaimer&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;. You can get the data &lt;a href=&quot;http://nomads.ncep.noaa.gov/&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="192" LastEditDate="2018-03-20T15:38:33.907" LastActivityDate="2018-03-20T15:38:33.907" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13659" PostTypeId="2" ParentId="13646" CreationDate="2018-03-20T17:29:15.703" Score="5" Body="&lt;p&gt;It is not an easy problem even for a simple object. The temperature will vary as the conditions change, but the usual approach to such problems is to find the equilibrium temperature for a set of conditions. This is, to find the final temperature that the object will reach if exposed to a given solar irradiation, with air at a given temperature, for given pressure, humidity, wind, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Such equilibrium state will allow you to find the temperature by assuming energy balance. That can be stated  as requiring that the &lt;strong&gt;incoming energy into the body equals the outgoing energy&lt;/strong&gt;, or&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$Ẹ_{in} = E_{out}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To simplify the explanation let's assume the object was in equilibrium with air temperature during the night and we want to calculate its temperature onces the sun is shining on it. In this case the incoming energy will be function of the absorbed solar energy, therefore it will be function of the radiation intensity ($R_{sun}$) that depends on solar elevation, cloud cover, etc. (and can be obtain as a direct output of climate models), the albedo of the object ($\alpha$) and the area exposed to sunlight (i.e. coross-section) ($A$), that will be given by the shape of the object, solar elevation and azimuth. So, that is equivalent to:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$E_{in}=R_{sun} (1-\alpha) A$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, the energy leaving the object will have two components.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Radiation: The object will cool down emitting electromagnetic radiation (mostly infrared) according to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law&quot; rel=&quot;noreferrer&quot;&gt;Stefan-Boltzmann law&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Conduction: As the object get hotter than the surrounding air, it will loose heat by &lt;a href=&quot;https://en.wikipedia.org/wiki/Thermal_conduction&quot; rel=&quot;noreferrer&quot;&gt;thermal conduction&lt;/a&gt; into it.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;So&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$E_{out}=\kappa (T - T_{air}) + \varepsilon \sigma T^4 S$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where $\kappa$ is the thermal conductivity of air, $T$ is the temperature of the object and $S$ its surface area. $\varepsilon$ is the emissivity (that is 1 for a black-body), and $\sigma$ the &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_constant&quot; rel=&quot;noreferrer&quot;&gt;Stefan-Boltzmann constant&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The three equations above are sufficient to solve for the temperature of the object&lt;/strong&gt;, but as you can see there are many parameters that depends on the object shape, and material, so it is impossible to generalize.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, in the absence of wind, the temperature of the air in contact with the object won't be the same as the surrounding air, further complicating the problem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, in addition to $A$, $\varepsilon$ and $\alpha$ can as well change with solar elevation and azimuth (if the object is made out different materials).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And to further complicate the problem, the thermal conductivity of the air $\kappa$ is a function of temperature, pressure and humidity. And it is not an easy relationship, it is usually tabulated or calculated using empirical formulas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At &lt;a href=&quot;https://www.engineeringtoolbox.com&quot; rel=&quot;noreferrer&quot;&gt;engineeringtoolbox.com&lt;/a&gt; you can find &lt;a href=&quot;https://www.engineeringtoolbox.com/air-properties-viscosity-conductivity-heat-capacity-d_1509.html&quot; rel=&quot;noreferrer&quot;&gt;tables and graphs of $\kappa$ for dry air&lt;/a&gt;, here is one example:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/lZgYD.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lZgYD.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the humidity have also an impact much more difficult to quantify, and whose importance grow with temperature. There is &lt;a href=&quot;https://www.electronics-cooling.com/2003/11/the-thermal-conductivity-of-moist-air/#&quot; rel=&quot;noreferrer&quot;&gt;an article at electronics-cooling.com&lt;/a&gt; that explain the effect, summarized in the following graph:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XlKr1.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XlKr1.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, that is hard enough for an object, let alone for a person. In such case there would a lot more parameters that come to play. Like the amount of insulation provided by clothing, surface and moisture content of the skin exposed to the wind, body heat production, etc.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Apparent temperature&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;That been said, there are some attempts to estimate the perceived temperature for people including humidity, wind &lt;strong&gt;and solar radiation&lt;/strong&gt;. The best example is perhaps the &lt;a href=&quot;https://en.wikipedia.org/wiki/Wet-bulb_globe_temperature&quot; rel=&quot;noreferrer&quot;&gt;Wet-bulb globe temperature&lt;/a&gt; ($\mathbf{WBGT}$), that consist on the weighted mean of the readings of three different types of thermometers: A normal one, a wet-bulb one (affected by wind and humidity) and a very uncommon &lt;a href=&quot;https://en.wikipedia.org/wiki/Mean_radiant_temperature&quot; rel=&quot;noreferrer&quot;&gt;black-globe thermometer&lt;/a&gt; (affected by solar radiation).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The formula is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\mathbf{WBGT} = 0.7 \, T_{wet-bulb} + 0.2 \, T_{black-globe} + 0.1 \, T_{air}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this value is not often used because is very location specific (depend on clouds for example). Nevertheless, perhaps a good approach you can take is to use actual solar irradiation from weather models to compute the temperature that a wet-bulb and a black-globe thermometer would produce, something that I think would be easy to achieve, and then compute the $\mathbf{WBGT}$ with the above formula.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Be aware that the $\mathbf{WBGT}$ value could be useful for people to know how cold/hot it will feel, but won't tell you anything about the actual temperature of different objects exposed to those conditions.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-20T18:11:15.163" LastActivityDate="2018-03-20T18:11:15.163" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13662" PostTypeId="1" CreationDate="2018-03-20T19:47:53.377" Score="8" ViewCount="541" Body="&lt;p&gt;That may sounds like a silly question but here it is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the early great successes of general relativity was to explain the discrepancy between the prehilion advance of Mercury predicted by Newtonian mechanics and the results of its actual measurement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was wondering if this kind of effect could have any influence on the climate of a planet experiencing it.&lt;/p&gt;&#xA;" OwnerUserId="12481" LastEditorUserId="11908" LastEditDate="2018-03-20T23:55:31.623" LastActivityDate="2018-03-21T13:25:49.713" Title="Does general relativity influence climate (vs Newtonian mechanics)" Tags="|climate|paleoclimatology|astronomy|milankovitch-cycles|orbit|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13663" PostTypeId="2" ParentId="13662" CreationDate="2018-03-20T20:17:11.807" Score="10" Body="&lt;p&gt;In short: No. Unless multi-million timescales are considered.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason we keep teaching Newtonian mechanics, is because it is a VERY accurate approximation of a more general theory (general relativity) within the regimes of speed and gravity acceleration found in everyday life. Therefore, all the relativistic corrections to Newtonian mechanics in the Earth system are negligible. Both, for the internal operations of the climate and for the evolution of its orbital parameters on timescales of hundreds of millennia or shorter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One effect, would be the minor role that apsidal precession have on the change of distribution of incoming solar energy described by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles#Orbital_shape_(eccentricity)&quot; rel=&quot;noreferrer&quot;&gt;Milankovic cycles&lt;/a&gt;. But that can arguably considered negligible. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But perhaps the most important contribution would be the influence of relativistic corrections in Earth's orbit eccentricity variations on multi-million years timescales.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;State-of-the-art orbital solutions for the long-term motion of the Earth like &lt;a href=&quot;https://www.aanda.org/articles/aa/pdf/2011/08/aa16836-11.pdf&quot; rel=&quot;noreferrer&quot;&gt;La2010&lt;/a&gt;, do use relativistic correction, however they are rather small. The way the corrections are included in the model are described by &lt;a href=&quot;http://articles.adsabs.harvard.edu/cgi-bin/nph-iarticle_query?1994AJ....108.1962S&amp;amp;data_type=PDF_HIGH&amp;amp;whole_paper=YES&amp;amp;type=PRINTER&amp;amp;filetype=.pdf&quot; rel=&quot;noreferrer&quot;&gt;Saha &amp;amp; Tremaine (1994)&lt;/a&gt;, where they point that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;General relativistic effects in planetary motion have fractional&#xA;  amplitude of order $\frac{k^2}{c^2 r} \sim 10^{-8}$ at $r = 1 \,  \textbf{AU}$.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Meaning that the correction correspond to a 0.000001% of the total variation of the orbital parameters. Unquestionably, even such small corrections have a cumulative effect over multi-million years timescales. &lt;a href=&quot;http://iopscience.iop.org/article/10.1086/375560/pdf&quot; rel=&quot;noreferrer&quot;&gt;Varadi et. at. (2003)&lt;/a&gt;, compares the output of a model using relativistic corrections (solid line) with one not using them (dashed line), and the following figure show the results over 3 million years, where can be observed that significant differences arise after 300,000 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6GSFD.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6GSFD.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it is reasonable to consider that such small corrections would have been overcome at some point in the past by some other unaccounted effects, like large meteorite impacts (or fly-by), solar storms, etc. Remember that La2010 go back 50 million years and &lt;a href=&quot;https://www.aanda.org/articles/aa/full/2004/46/aa1335/aa1335.html&quot; rel=&quot;noreferrer&quot;&gt;other models go back several billion years&lt;/a&gt;, when such events were rather common. So, I would still argue that relativistic corrections are not very significant. However, in a chaotic system like Earth's climate, you can never rule out that a negligible forcing could have had an important effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course the answer would be different (and the relative importance higher) if we consider a planet orbiting extremely close to a super-massive star. But, I'm assuming you are mostly considering planets similar to Earth in that regard.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are also some claims (the &lt;a href=&quot;http://lasp.colorado.edu/sorce/news/2008ScienceMeeting/posters/P4_01_Lynch_Poster.pdf&quot; rel=&quot;noreferrer&quot;&gt;Damhsa Theory&lt;/a&gt;) that gravitational waves might have play a role in the very long term climate evolution of Earth. However, I'm not capable to really assess the validity of such theory, but I have to admit I'm skeptical about it. I've posted &lt;a href=&quot;https://physics.stackexchange.com/questions/394552/damhsa-theory-can-gravitational-waves-really-affect-the-long-term-climatic-evo&quot;&gt;a question about that&lt;/a&gt; in Physics SE, an there seem to be wide consensus that such effect would be exceedingly small to ever deserve any kind of consideration.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-21T00:22:14.277" LastActivityDate="2018-03-21T00:22:14.277" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13664" PostTypeId="1" AcceptedAnswerId="13674" CreationDate="2018-03-20T22:18:24.383" Score="6" ViewCount="6320" Body="&lt;p&gt;Ozone is considered a greenhouse gas, even though it absorbs shortwave (UV) radiation from the Sun, which does not fit with the definition for &lt;a href=&quot;https://en.wikipedia.org/wiki/Greenhouse_gas&quot; rel=&quot;noreferrer&quot;&gt;greenhouse gases&lt;/a&gt;, where they are supposed to:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;absorbs and emits radiant energy within the thermal infrared range&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(Quote from &lt;a href=&quot;https://en.wikipedia.org/wiki/Greenhouse_gas&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;PS: This is an adaptation of a question asked in the private discussion board of a first year university course on Earth Sciences, that I'm copying here so a wider community can benefit from it and the corresponding answer. As suggested by the moderators, I'll donate any reputation received from this question in the form of a bounty awarded to exceptional answers (in particular by new or low-rep users).&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-03-11T23:22:31.880" LastActivityDate="2019-03-11T23:22:31.880" Title="Why is ozone a greenhouse gas if it absorb UV radiation?" Tags="|climate-change|atmospheric-radiation|ozone|greenhouse-gases|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13665" PostTypeId="2" ParentId="13664" CreationDate="2018-03-20T22:18:24.383" Score="4" Body="&lt;p&gt;Ozone is indeed a greenhouse gas. But not due to its capacity to absorb/scatter UV radiation, but instead due to its capacity to absorb infrared radiation. In contrast with other greenhouse gases (Like $CO_2$ or Methane), the spectral absorption bands of Ozone are not confined to the infrared part of the spectrum, there are ozone absorption bands also the UV too.&#xA;However, if ozone were capable to absorb only UV radiation, it would NOT be a greenhouse gas. Because the Earth's surface do not emit UV radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, the greenhouse gas properties of Ozone do not come from its ultraviolet absorption bands, but instead from its infrared absorption bands, that you can see in the following infrared spectrum obtained from &lt;a href=&quot;https://webbook.nist.gov/cgi/cbook.cgi?ID=C10028156&amp;amp;Units=SI&amp;amp;Mask=80#IR-Spec&quot; rel=&quot;nofollow noreferrer&quot;&gt;NIST&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/F47Ky.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/F47Ky.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-03-20T22:18:24.383" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13666" PostTypeId="2" ParentId="13662" CreationDate="2018-03-21T00:18:32.230" Score="3" Body="&lt;p&gt;The latest positions that I am aware of say yes, but not in any useful way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From what I have read, the current prevailing opinion is that the weather of Earth is a chaotic system.  Chaotic systems are known to be very sensitive to initial conditions.  Eddys in the atmosphere that are mere milimeters in size may change whether it rains or shines on the other side of the planet in a few months.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From this concept, we can assume that GR affects the weather.  However, we have to be cautious with what we draw from that conclusion.  I believe it was von Neuman who is quoted as saying that when he first heard of the idea of weather as a chaotic system, sensitive to initial conditions, he had the idea that we might soon have weather control simply by doing small adjustments.  Only later did he finally understand chaos theory: such perturbations were like giving a well shuffled desk another shuffle.  It certainly changes your luck, but you couldn't possibly know if it was for better or for worse.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to your question, as to whether GR would have &lt;em&gt;any&lt;/em&gt; effect, the answer is yes.  If you were to rephrase the question to ask whether it had any measurable effects that might be tested with empirical evidence, then I would have to defer to Camilo's answer.&lt;/p&gt;&#xA;" OwnerUserId="12482" LastActivityDate="2018-03-21T00:18:32.230" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13669" PostTypeId="1" AcceptedAnswerId="13670" CreationDate="2018-03-21T03:59:20.913" Score="5" ViewCount="318" Body="&lt;p&gt;I understand why foram shells contain more $^{18}\text{O}$ when there are ice sheets present, since $^{16}\text{O}$ evaporates more readily and gets trapped in the ice, increasing the relative abundance of $^{18}\text{O}$ in seawater. However, in the absence of ice sheets: &lt;strong&gt;What is the reason for there being more $^{18}\text{O}$ in the foram shells in colder climates?&lt;/strong&gt; Since I assume the evaporated $^{16}\text{O}$ would just get returned to the sea by rain and rivers if it's not being trapped in ice.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;PS: This is an adaptation of a question asked in the private discussion board of a first year university course on Earth Sciences, that I'm copying here so a wider community can benefit from it and the corresponding answer. As suggested by the moderators, I'll donate any reputation received from this question in the form of a bounty awarded to exceptional answers (in particular by new or low-rep users).&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-21T04:31:40.877" LastActivityDate="2018-03-21T04:33:18.167" Title="Why the $\delta \, ^{18}\text{O}$ in foraminifera shells decrease with temperature even if the oceanic $\delta \, ^{18}\text{O}$ stay constant?" Tags="|climate-change|oceanography|paleoclimatology|fossils|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13670" PostTypeId="2" ParentId="13669" CreationDate="2018-03-21T03:59:20.913" Score="5" Body="&lt;p&gt;That is because the chemical reactivity of $^{18}\text{O}$ is slightly higher than that of $^{16}\text{O}$. For that reason, the biochemical reactions that produce calcium carbonate in foraminifera prefer $^{18}\text{O}$ over $^{16}\text{O}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the temperature dependence arise from the fact that the difference in reactivity is smaller when temperature increase. Therefore, in warmer temperatures the $\delta ^{18}\text{O}$ will be more similar to seawater (no preference for any isotope), but at colder temperatures the chemical preference for $^{18}\text{O}$ will be stronger and, therefore, the $\delta ^{18}\text{O}$ will increase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This correlation with temperature is also known as the &quot;paleotemperature equation&quot;, but as it is an empiric equation there are many slightly different versions, however all of them are pretty consistent. Several ones are summarized in figure 5 of the paper &lt;a href=&quot;https://pdfs.semanticscholar.org/4edf/ee5ecd2975de584b116a73def1ba29e88899.pdf&quot; rel=&quot;noreferrer&quot;&gt;Oxygen isotopes in foraminifera: Overview and historical review (Pearson 2012)&lt;/a&gt; copied below, showing how the excess of $\delta ^{18}\text{O}$ in shells ($\delta ^{18}\text{O}_{\text{cc}}$) relative to the $\delta ^{18}\text{O}$ in seawater ($\delta ^{18}\text{O}_{\text{sw}}$) correlates with water temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1ii0s.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1ii0s.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The deeper reason that explain the chemical preference for $^{18}\text{O}$ come from a process named &quot;equilibrium isotope fractionation&quot;, associated  to the vibrational characteristics of the light and heavy isotopes related to covalent atomic bonding.&#xA;As explained by &lt;a href=&quot;https://epic.awi.de/6092/1/Gus2003a.pdf&quot; rel=&quot;noreferrer&quot;&gt;Gussone et. al (2003)&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Equilibrium fractionation occurs as a consequence of covalent atomic&#xA;  bonding. During molecule formation the incorporation of heavier&#xA;  isotopes is preferred because covalent atomic bonds formed with&#xA;  heavier isotopes show larger bonding energies and, hence, are more&#xA;  stable than covalent bonds formed with lighter isotopes.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There is a competing effect called &quot;kinetic isotope fractionation&quot;, that that leads to a correlation with temperature in the opposite direction (because heavier isotopes have slower diffusion times and are slower crossing membranes), but in the case of Oxygen isotopes, its effects is overcome by equilibrium fractionation.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-21T04:33:18.167" LastActivityDate="2018-03-21T04:33:18.167" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13671" PostTypeId="1" AcceptedAnswerId="13682" CreationDate="2018-03-21T05:10:23.747" Score="5" ViewCount="1100" Body="&lt;p&gt;I've always been told that the equator is the region on Earth that receives the most sunlight.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I wondered, since the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ecliptic&quot; rel=&quot;nofollow noreferrer&quot;&gt;ecliptic&lt;/a&gt; is the circular path that the Sun appears to follow over the course of a year, then wouldn't the ecliptic path receive more sunlight than the equator? &lt;/p&gt;&#xA;" OwnerUserId="12484" LastEditorUserId="11908" LastEditDate="2019-03-11T21:07:56.983" LastActivityDate="2021-09-23T12:20:34.047" Title="Why does more sunlight hits the equator than the ecliptic path?" Tags="|geography|astronomy|equator|orbit|insolation|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13672" PostTypeId="1" CreationDate="2018-03-21T08:12:22.650" Score="3" ViewCount="87" Body="&lt;p&gt;I wondered what causes three wind cells on earth -Hadley Cells, Ferrel Cells, and Polar Cells, instead of just a one big cell from equator to the pole?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd like a straightforward, intuitive explanation as to why there are multiple cells. The actual calculations aren't as important.&lt;/p&gt;&#xA;" OwnerUserId="12484" LastEditorUserId="6467" LastEditDate="2018-03-22T10:32:32.787" LastActivityDate="2018-03-22T10:32:32.787" Title="why does Earth have three wind cells instead of just one?" Tags="|wind|geothermal-heat|equator|" AnswerCount="0" CommentCount="3" ClosedDate="2018-03-24T19:17:51.163" ContentLicense="CC BY-SA 3.0" />
  <row Id="13673" PostTypeId="1" AcceptedAnswerId="13677" CreationDate="2018-03-21T09:51:50.457" Score="10" ViewCount="909" Body="&lt;p&gt;I am interested in earth system models, land surface models and climate prediction models. I found a lot of online information on different models, including CIMP5, and the Earth System Modeling Framework. I also found a lot of articles using these models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to run and experiment with these models on my own computer. However, I could not find any clear installation guides or code examples on how to run these models. I would like to have a step by step instruction how to install the model, how to include the input data, how to run the model and how to view the output. There must be decent tutorials somewhere out there. I am particularly interested in models using Normalized Difference Vegetation Index (NDVI) and Leaf area index (LAI) data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the time being it should be something that can be run on a desktop computer or in a virtual machine, but I also have access to more powerful clusters.&lt;/p&gt;&#xA;" OwnerUserId="364" LastActivityDate="2018-04-11T22:38:26.220" Title="How to run earth system, land surface and climate models?" Tags="|models|climate-models|earth-system|land-surface-models|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13674" PostTypeId="2" ParentId="13664" CreationDate="2018-03-21T10:59:43.170" Score="3" Body="&lt;p&gt;Tropospheric (near the surface) ozone is a powerful greenhouse gas, even in trace amounts.   Strataspheric ozone or the ozone layer is opaque to UV rays coming in and it's opaque to IR rays going out so it has both warming and cooling effects.  The net effect of a thickening of the ozone layer is a small warming (with some uncertainty), so the ozone layer is not a very strong heat trapping driver, but ozone in the lower atmosphere is, and it's a strong heat trapping gas one too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ozone is very reactive and as a result, it has a very short atmospheric lifetime.  (&lt;a href=&quot;https://en.wikipedia.org/wiki/Greenhouse_gas#cite_note-blasing_pre_1750_ghg_conc-51&quot; rel=&quot;nofollow noreferrer&quot;&gt;hours-days&lt;/a&gt;), but what Ozone has is an equilibrium concentration in the atmosphere (&lt;a href=&quot;https://en.wikipedia.org/wiki/Greenhouse_gas#Natural_and_anthropogenic_sources&quot; rel=&quot;nofollow noreferrer&quot;&gt;337 ppb&lt;/a&gt;).  It's concentration is maintained in the troposphere by &lt;a href=&quot;https://www.sciencedaily.com/terms/tropospheric_ozone.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;sunlight hitting trace elements in the atmosphere&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The majority of tropospheric ozone formation occurs when nitrogen&#xA;  oxides (NOx), carbon monoxide (CO) and volatile organic compounds&#xA;  (VOCs), such as xylene, react in the atmosphere in the presence of&#xA;  sunlight.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;NOx and VOCs are called ozone precursors.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Motor vehicle exhaust, industrial emissions, and chemical solvents are&#xA;  the major anthropogenic sources of these chemicals&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;If, for example, you were to release several billion tons of Ozone on the surface of a planet to increase it's greenhouse effect, the effect wouldn't last long because because ozone is for the most part an unstable molecule.  It needs to be constantly recreated because it tends to chemically react and stop being Ozone very quickly for an atmospheric gas.  As noted in the quote above, motor vehicle exhaust has increased the atmospheric material that ozone gets created from in our lower atmosphere, so there are man-made reasons for the increase in tropospheric ozone concentration, 237 ppb in 1750 to 337 ppb today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Greenhouse_gas#cite_note-59&quot; rel=&quot;nofollow noreferrer&quot;&gt;This reference&lt;/a&gt; from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Greenhouse_gas#Natural_and_anthropogenic_sources&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia article&lt;/a&gt;, notes that the Ozone layer has a minor cooling effect, (&lt;a href=&quot;http://cdiac.ess-dive.lbl.gov/pns/current_ghg.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source article here&lt;/a&gt;), quote from footnote 6&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Radiative forcing for tropospheric ozone is taken from the 5th column&#xA;  of Table 8.6 of IPCC (2013).&#xA;  &lt;a href=&quot;http://www.climatechange2013.org/images/report/WG1AR5_Chapter08_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.climatechange2013.org/images/report/WG1AR5_Chapter08_FINAL.pdf&lt;/a&gt;&#xA;  The &quot;current&quot; value in that table refers to a global average. Note, in&#xA;  the row immediately below the number for tropospheric forcing, the&#xA;  stratospheric forcing is given as negative 0.05 W/m2&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://www.climatechange2013.org/images/report/WG1AR5_Chapter08_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;82 page IPCC report on radiative forcing&lt;/a&gt; from which that article references has this to say on it's introductory remarks on Ozone:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The total RF estimated from modelled ozone changes is 0.35 (0.15 to&#xA;  0.55) W m–2, with RF due to tropospheric ozone changes of&#xA;  0.40 (0.20 to 0.60) W m–2 and due to stratospheric ozone changes of –0.05 (–0.15 to +0.05) W m–2. Ozone is not emitted directly into the&#xA;  atmosphere but is formed by photochemical reactions. Tropospheric&#xA;  ozone RF is largely attributed to anthropogenic emissions of methane&#xA;  (CH4), nitrogen oxides (NOx), carbon monoxide (CO) and non-methane&#xA;  volatile organic compounds (NMVOCs), while stratospheric ozone RF&#xA;  results primarily from ozone depletion by halocarbons. Estimates are&#xA;  also provided attributing RF to emitted compounds. Ozone-depleting&#xA;  substances (ODS) cause ozone RF of –0.15 (–0.30 to 0.0) W m–2, some of&#xA;  which is in the troposphere. Tropospheric ozone precursors cause ozone&#xA;  RF of 0.50 (0.30 to 0.70) W m–2, some of which is in the stratosphere;&#xA;  this value is larger than that in AR4. There is robust evidence that&#xA;  tropospheric ozone also has a detrimental impact on vegetation&#xA;  physiology, and therefore on its CO2 uptake, but there is a low&#xA;  confidence on quantitative estimates of the RF owing to this indirect&#xA;  effect. RF for stratospheric water vapour produced by CH4 oxidation is&#xA;  0.07 (0.02 to 0.12) W m–2. The RF best estimates for ozone and stratospheric water vapour are either identical or consistent with the&#xA;  range in AR4. {8.2, 8.3.3, Figure 8.7}&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;From page 3 of this link, chapter 8, page 661 of the AR5 report.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What the report basically says is that tropospheric ozone has a significant greenhouse effect, 0.4 watts per square meter as a result of the man-made increase since 1750, which is nearly equal to the warming from the methane increase, despite measurably lower total concentration and a lower percentage increase.  (note, there are considerable measurement uncertainties, 0.2 to 0.6 is given as the range).   But even the low end of that estimate makes ozone in the lower atmosphere a powerful greenhouse gas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Ozone layer (0.05 watts per square meter cooling estimate) corresponds to a thinner ozone layer today compared to 1750 (as far as I can tell, I didn't see that spelled out), but assuming that's the case, a thicker ozone layer should (could) provide a small amount of warming, but 0.05 watts per square meter variation is pretty insignificant.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2018-03-21T11:28:11.120" LastActivityDate="2018-03-21T11:28:11.120" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13676" PostTypeId="2" ParentId="13662" CreationDate="2018-03-21T13:25:49.713" Score="3" Body="&lt;p&gt;I don't see this point made, so I'll just add it.   In very high gravitation situations orbital energy can be lost to &quot;relativity&quot; or more specifically, gravity waves.  The primary relativistic effect that the Sun's gravity has on Mercury is an increase in it's precession, as @CamiloRada pointed out, and &lt;a href=&quot;https://physics.stackexchange.com/questions/26408/what-did-general-relativity-clarify-about-mercury&quot;&gt;see more details here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A secondary relativistic effect is orbital decay, or spiraling in.  This is &lt;a href=&quot;https://www.forbes.com/sites/chadorzel/2015/07/22/three-experiments-that-show-relativity-is-real/2/#72c35a8443a9&quot; rel=&quot;nofollow noreferrer&quot;&gt;observable in tight orbits around neutron stars&lt;/a&gt; or black holes.  The effect around a regular star would be tiny but non zero.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This &lt;a href=&quot;https://www.forbes.com/sites/startswithabang/2016/12/27/gravitational-waves-from-discovery-of-the-year-to-science-of-the-century/#6ee4dfe5087f&quot; rel=&quot;nofollow noreferrer&quot;&gt;article gives some numbers for this effect on the Earth&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Gravitational radiation is incredibly subtle and weak in its effects.&#xA;  The Earth, as it orbits the Sun, loses energy due to this radiation&#xA;  and spirals inwards. But it will take 10^150 years for this process to&#xA;  occur.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That's a preposterously long period of time.  Mercury would certainly be effected significantly more than Earth, (I can't do the math, maybe someone here will step up), but even at mercury distance the energy loss to gravity waves and spiraling-in would be slow to the point of irrelevance compared to other effects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Our sun, for example, grows larger and brighter over it's lifetime. Planets atmosphere's change, either stripped off or in the case of Earth, affected by photosynthesis and other processes, and the Sun loses mass over it's lifetime, which causes the planets, on average to move outwards, though inward migration is also thought to be possible and the planets can affect each other's orbits.  These changes to climate are all likely to be significantly greater than relativistic spiraling-in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For maximum &quot;spiral-in&quot; effect, you'd probably want a small star and a planet with a very tight orbit of just days, but even that would likely be too small to have significant effects and a planet that orbited faster than it's star rotates would likely experience some tidal forces drawing it inwards.  The tidal drawing-in would likely be far greater.   It's hard to imagine a situation where the relativistic spiraling-in would have much effect between a planet and star.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now a planet in a super-tight orbit around a white-dwarf star . . . maybe, but the planet would likely get torn apart inside the Roche limit long before you got it close enough for any measurably interesting relativistic spiraling-in.  &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;A word on precession, precession affects the Earth's climate because the Earth has a land dominant hemisphere and a water dominant hemisphere.  Precession also works with the seasons leading to warmer or colder winters or summers.   If there's low axial tilt, then precession won't have much effect on a planet's climate.  Mercury has minimal axial tilt and no significant variation between it's two hemispheres, so it's unlikely that Mercury's precession changes it's climate much.  Certainly not like the effect it has on Earth, such as turning ice ages on or off.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Precession is also mostly Newtonian.   Relativity just adds a percentage point or two to the rate of precession in the case of Mercury.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2018-03-21T13:25:49.713" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13677" PostTypeId="2" ParentId="13673" CreationDate="2018-03-21T14:13:37.773" Score="9" Body="&lt;p&gt;As alluded to in some of the comments, all of the CMIP5 models will have been run on supercomputers, and it takes a &lt;em&gt;lot&lt;/em&gt; of effort to get one of them running on a new platform, even for a team who know both the model and platform well already.  In addition to that, many of those models are closed-source and are not generally available to an individual researcher.  However, there are several older models such as &lt;a href=&quot;http://mitgcm.org/public/testing.html&quot; rel=&quot;noreferrer&quot;&gt;MITgcm&lt;/a&gt; and &lt;a href=&quot;http://edgcm.columbia.edu/ModelII/&quot; rel=&quot;noreferrer&quot;&gt;EdGCM&lt;/a&gt; that it might well be possible to get running on a cluster.  It's something I've thought about but never quite got around to.  One group have even been&#xA;&lt;a href=&quot;https://doi.org/10.1016/j.cageo.2016.09.014&quot; rel=&quot;noreferrer&quot;&gt;running CESM on Amazon's EC2 service&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Depending on what aspect of leaf phenology you're interested in, you may need to run quite long simulations (e.g., several centuries), which is prohibitive with a full ESM.  You can make a lot of progress in this area by running just the land surface components.  This is several orders of magnitude simpler than running an ESM: the source codes are often freely available where their host ESM code is not, and they can be run globally on desktop machines or clusters.  Some example land surface models you might want to look into:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.cesm.ucar.edu/models/clm/&quot; rel=&quot;noreferrer&quot;&gt;Community Land Model (CLM)&lt;/a&gt; (used in CCSM, US)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://jules.jchmr.org/&quot; rel=&quot;noreferrer&quot;&gt;JULES&lt;/a&gt; (used in HadGEM, UK)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.cawcr.gov.au/research/cable/&quot; rel=&quot;noreferrer&quot;&gt;CABLE&lt;/a&gt; (used in ACCESS, Aus)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://orchidee.ipsl.fr/index.php/you-orchidee&quot; rel=&quot;noreferrer&quot;&gt;ORCHIDEE&lt;/a&gt; (used in IPSL-CM5, Fr)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.umr-cnrm.fr/surfex/&quot; rel=&quot;noreferrer&quot;&gt;SURFEX&lt;/a&gt; (used in CNRM-CM5, Fr)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Each of these will require a set of forcing boundary conditions, and there are several commonly used by the land community:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;GSWP3&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.eu-watch.org/data_availability&quot; rel=&quot;noreferrer&quot;&gt;WFDEI&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://rda.ucar.edu/datasets/ds314.3/&quot; rel=&quot;noreferrer&quot;&gt;CRU-NCEP&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://hydrology.princeton.edu/data.pgf.php&quot; rel=&quot;noreferrer&quot;&gt;Princeton&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;If you go down the land surface route (and I suggest that's a good place to start), you should probably just pick a model and ask it's community directly about the details of getting it running.  In my experience, several of them have very good tutorials especially for people with a bit of Linux experience.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2018-03-21T14:13:37.773" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13680" PostTypeId="2" ParentId="13527" CreationDate="2018-03-21T19:28:45.420" Score="3" Body="&lt;p&gt;In most of Western Europe, precipitation comes from westerly winds formed over the warm waters of the Gulf Stream current that flows from the Caribbean to Western Europe. That is a warm current, so these winds would be warmer and make your area warmer. Besides, as they come from a warm ocean they are moist and carry water vapor and make clouds. Low temperatures are usually caused by easterly/northerly winds originating in Siberia, these are cold and come from land. Cold winds cannot carry moisture and on top of that they travel over land rather than the ocean and are dry. So in most cases in European winter, relative warmth and precipitation go hand-in-hand.&lt;/p&gt;&#xA;" OwnerDisplayName="user12493" LastActivityDate="2018-03-21T19:28:45.420" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13682" PostTypeId="2" ParentId="13671" CreationDate="2018-03-21T20:31:05.573" Score="8" Body="&lt;p&gt;The ecliptic path, is a well defined trajectory when displayed on the background of the fix stars like in the following figure&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/C0INq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/C0INq.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(taken from &lt;a href=&quot;http://www.physics.csbsju.edu/astro/SC1/SC1.07.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;physics.csbsju.edu&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;However, &lt;strong&gt;there is not such thing as an ecliptic path on the surface of the Earth&lt;/strong&gt;. If you thought of it as the &amp;quot;Ground track&amp;quot; of a satellite but applied for the Sun, you have to consider that the rotation of the Earth would make that &amp;quot;ground track&amp;quot; of the Sun look &lt;strong&gt;very&lt;/strong&gt; different than the one on the figure above. It would be a spiral going around the Earth ~365 times at latitudes between the tropics of Cancer and Capricorn (remember that the Sun takes a full year to go trough the ecliptic path).&lt;/p&gt;&#xA;&lt;p&gt;When the Sun is at its Northernmost declination (the top point of the red curve above), which is ~23° all the points on Earth at latitude ~23° North (the tropic of Cancer) will receive the maximum possible solar irradiation at the solar noon of that day. Once the Sun moves down to declination 22°, it will be the turn of the points at 22° North and so on.&lt;/p&gt;&#xA;&lt;p&gt;The reason why the Equator is the line that receive the most solar radiation is because it is the one that is &lt;strong&gt;on average&lt;/strong&gt; closer to the Sun's ground track (in other words, is the place with the maximum mean solar elevation).&lt;/p&gt;&#xA;&lt;p&gt;An equivalent visualisation would be to take the mean of the ecliptic, and by looking at the above red line it is quite straightforward to see that it would be a flat line on the celestial equator, that translates to the Earth's equator.&lt;/p&gt;&#xA;&lt;p&gt;Does that makes sense to you?&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="18081" LastEditDate="2021-09-23T12:20:34.047" LastActivityDate="2021-09-23T12:20:34.047" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="13683" PostTypeId="1" CreationDate="2018-03-22T00:18:07.350" Score="3" ViewCount="77" Body="&lt;p&gt;The Siberian High is a very strong anticyclone present over Siberia in the winter. Cities like Irkutsk lie at its very center, yet Irkutsk has 18-20 days of snow per month in the winter. Shouldn't we expect cloudless, clear skies under a strong high pressure, rather than two-thirds of the days having precipitation?&lt;/p&gt;&#xA;" OwnerDisplayName="user12493" LastActivityDate="2018-03-22T00:18:07.350" Title="Snow under Siberian High" Tags="|meteorology|climate|snow|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13687" PostTypeId="1" CreationDate="2018-03-22T10:43:03.380" Score="1" ViewCount="23" Body="&lt;p&gt;In the &lt;a href=&quot;https://en.wikivoyage.org/wiki/Vietnam#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;climate&lt;/a&gt; section of Wikivoyage's guide to Vietnam, it's claimed that the highlands of Vietnam have both colder winters, and hotter summers:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The north has four distinct seasons, with a comparatively chilly winter (temperatures can dip below 15°C/59°F in Hanoi), a hot and wet summer and pleasant spring (Mar-Apr) and autumn (Oct-Dec) seasons. However, in the Highlands both extremes are amplified, with occasional snow in the winter and temperatures hitting 40°C (104°F) in the summer.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Similar things are said &lt;a href=&quot;https://www.vietnam-travel-guide.net/vietnam-weather/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;There are extremes in the Highlands as snow sometimes falls in the winter whilst the summer can see temperatures up around 40ºC.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and a similar thing is said in Wikipedia's article on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Geography_of_Vietnam#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;geography of Vietnam&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Seasonal divisions are more clearly marked in the northern half than in the southern half of the country, where, except in some of the highlands, seasonal temperatures vary only a few degrees, usually in the 21–28 °C (69.8–82.4 °F) range.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I thought that increased altitude merely meant a consistent reduction in temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does Vietnam's highlands have hotter summers as well as colder winters compared to lower lying areas, and if so, why?&lt;/p&gt;&#xA;" OwnerUserId="2658" LastActivityDate="2018-03-22T10:43:03.380" Title="Does Vietnam's highlands have both colder winters and hotter summers than lower lying areas?" Tags="|climate|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13688" PostTypeId="1" CreationDate="2018-03-22T11:12:02.890" Score="5" ViewCount="727" Body="&lt;p&gt;Here, I have a regional emission inventory, which mainly contains the varibales of &lt;code&gt;lat&lt;/code&gt;,&lt;code&gt;lon&lt;/code&gt;,&lt;code&gt;emission&lt;/code&gt;,and the &lt;code&gt;emission&lt;/code&gt;shape is &lt;code&gt;(lat,lon)&lt;/code&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example :&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://db.cger.nies.go.jp/dataset/ODIAC/DL_odiac2017.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ODIAC&lt;/a&gt;, the  spatial resolution is &lt;code&gt;1*1 deg&lt;/code&gt;, and emission shape is &lt;code&gt;(180,360)&lt;/code&gt;，units : gC/m2/d;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://hestia.project.asu.edu/audience_researchers.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hestia&lt;/a&gt;, the spatial resolution is &lt;code&gt;0.002*0.002 deg&lt;/code&gt;, and the emission shape is &lt;code&gt;(521,560)&lt;/code&gt;,units: Kg;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;For now, I have to map the emission from the geographic coordinate &lt;code&gt;(lat,lon)&lt;/code&gt; to WRF model grid, which may look like &lt;code&gt;99*99&lt;/code&gt; with grid spacing of &lt;code&gt;3km&lt;/code&gt;,or &lt;code&gt;87*87&lt;/code&gt; with  grid spacing of &lt;code&gt;1km&lt;/code&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems that the process of mapping involves the calculation of area of old grid of emission inventory.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am confused about how to do. Is there any efficient method to deal with it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for all the help.&lt;/p&gt;&#xA;" OwnerUserId="12411" LastEditorUserId="12411" LastEditDate="2018-03-22T15:12:40.690" LastActivityDate="2018-10-16T20:28:11.740" Title="How to map emission inventory from lat&amp;lon corrdinate to WRF model grid" Tags="|atmosphere-modelling|air-pollution|wrf|python|wrf-chem|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13690" PostTypeId="1" CreationDate="2018-03-22T11:55:29.213" Score="7" ViewCount="81" Body="&lt;p&gt;We are a spin-off from TU Munich and currently working on equipping a &#xA;CubeSat with a thermal imager.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The imager should be able to acquire thermal/ir images with resolution of about 200m/px. In the future we see a high potential for building a constellation of such satellites to enable a 10min temporal resolution over all surface temperature data on the globe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do you use any data beside those publicly available from NASA and ESA? Which ones?&#xA;What may be some uses of such high temporal resolution surface temperature data?&lt;/p&gt;&#xA;" OwnerUserId="12497" LastEditorDisplayName="user1066" LastEditDate="2018-03-23T13:55:07.853" LastActivityDate="2018-03-23T13:55:07.853" Title="Global Land and Sea Surface Temperature Data" Tags="|temperature|earth-system|satellites|weather-satellites|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13691" PostTypeId="1" CreationDate="2018-03-22T13:39:01.707" Score="4" ViewCount="48" Body="&lt;p&gt;Will GW just cause more winter storms in Northeast US or will all of US have colder winters ? This winter in East TX we had three record cold snaps and I lost a lot of Camellia Japonica buds and blooms. Most years I lose a few blooms but usually not the buds also. This is the most I have lost in 20 years. I am hoping we will not get the cold like the northeast.. I have watched the weather channels ; they usually explain how GW causes more storms/ rain, etc, but they have not yet explained the relationship to GW for these storms. &lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2018-03-22T13:39:01.707" Title="Will global Warming continue to produce winter storms in the Northeast US?" Tags="|meteorology|weather-forecasting|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13692" PostTypeId="1" AcceptedAnswerId="13694" CreationDate="2018-03-22T13:44:36.940" Score="5" ViewCount="2653" Body="&lt;p&gt;Is there available information on how much of Earth surface is arid climate? &lt;/p&gt;&#xA;" OwnerUserId="9635" LastEditorUserId="9635" LastEditDate="2019-01-04T23:58:35.910" LastActivityDate="2019-05-07T09:02:09.387" Title="What percentage of Earth's surface is arid?" Tags="|climate|geography|climatology|desert|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="13694" PostTypeId="2" ParentId="13692" CreationDate="2018-03-22T17:12:06.420" Score="8" Body="&lt;p&gt;It will depend on the exact definition of &quot;arid&quot; and the period of time. But using the widely used and accepted &lt;a href=&quot;https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification&quot; rel=&quot;noreferrer&quot;&gt;Köppen climate classification&lt;/a&gt;, &quot;arid&quot; would correspond to the four climates in &lt;a href=&quot;https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification#Group_B:_Dry_(desert_and_semi-arid)_climates&quot; rel=&quot;noreferrer&quot;&gt;climatic group B&lt;/a&gt;: &quot;&lt;strong&gt;Dry (desert and semi-arid) climates&lt;/strong&gt;&quot;. Using &lt;a href=&quot;http://koeppen-geiger.vu-wien.ac.at/present.htm&quot; rel=&quot;noreferrer&quot;&gt;the most up-to-date present climate data (2006)&lt;/a&gt; provided by the &lt;a href=&quot;http://koeppen-geiger.vu-wien.ac.at/&quot; rel=&quot;noreferrer&quot;&gt;WORLD MAPS OF KÖPPEN-GEIGER CLIMATE CLASSIFICATION&lt;/a&gt; at 0.5° of resolution, that looks like this (in an equal area projection):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sLj6J.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sLj6J.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We get that the four arid climates (group B), add up to $4.401 \times &#xA; 10^7 {km}^2$ of a total of $1.527 \times &#xA; 10^8 {km}^2$ inventoried in the dataset (A good match for the figure of of &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth&quot; rel=&quot;noreferrer&quot;&gt;global land area of $1.489 \times 10^8 km^2$ listed by wikipedia&lt;/a&gt;), leading to a grand total of &lt;strong&gt;28.8% of Earth's land surface corresponding to arid climates&lt;/strong&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-22T17:53:45.977" LastActivityDate="2018-03-22T17:53:45.977" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13696" PostTypeId="1" AcceptedAnswerId="13698" CreationDate="2018-03-22T20:12:11.283" Score="8" ViewCount="6520" Body="&lt;p&gt;I am trying to learn meteorology through self-study.  I have found quite a few lectures on YouTube, but they tend to be for non-scientists.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have a strong engineering and physics background and am looking for a text that presumes you can think through thermodynamics.  Many of the ones I can see a sample of online at Amazon sort of hide the real depth to help the reader not need to understand that sort of background.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone know of a good textbook that one would use at the undergrad level if you were trying to major in meterology, as opposed to a survey type course?&lt;/p&gt;&#xA;" OwnerUserId="12502" LastEditorUserId="18081" LastEditDate="2022-08-04T09:08:15.537" LastActivityDate="2022-12-24T12:25:16.987" Title="Can anyone recommend a good college level meteorology textbook?" Tags="|meteorology|reference-request|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13697" PostTypeId="2" ParentId="2161" CreationDate="2018-03-22T20:46:04.733" Score="2" Body="&lt;p&gt;For question 1), the exact number will vary depending on the elevation model you use for the calculation. High resolution elevation models are available for land, but for sea the resolution is much lower. The best global elevation model covering both land and seafloor is arguable &lt;a href=&quot;https://www.ngdc.noaa.gov/mgg/global/global.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ETOPO1&lt;/a&gt;, with a resolution of about 2 km. And if we mask all areas outside of the range -200 to 800 m it turns into this&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LMpUp.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LMpUp.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And you can see that most tropical forest and large areas of boreal forest are included, so I wouldn't be surprised if 99% of living &lt;strong&gt;land&lt;/strong&gt; species are within those ranges.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, the total area within those limits tuns out to be $1.286 \times 10^8 {km}^2$ of a total of $5.095 \times 10^8 {km}^2$ (A good match for the figure of &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;$5.101 \times 10^8 {km}^2$ listed by wikipedia&lt;/a&gt;). &lt;strong&gt;Giving a total of 25.2% of Earth's surface&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From that total, a 5.3% is contributed by the terrain between -200 m and sea level ($0.270 \times 10^8 {km}^2$).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that so far we have NOT made any distinction between water covered and dry surface. Now, that distinction seem weird to me, as it rules out massive areas of shallow seas full of life. The &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0960982212011529&quot; rel=&quot;nofollow noreferrer&quot;&gt;oceans are know to contain 15% of the known species&lt;/a&gt;, therefore, ruling them out immediately render the &quot;99% claim&quot; invalid. Instead, that distinction seem to be there to include the minuscule amount of dry land between 0 and -200 m, that in turn is in general very dry (otherwise they would become lakes) something that doesn't makes any sense to me. If the sentence you heard really refers to &quot;dry land&quot;, I would think &lt;strong&gt;it must then refer to land species only&lt;/strong&gt;. Anyway, it is not difficult to properly answer question 1  by quantify the relevance of those below-sea-level dry areas. That can be accomplished using the &lt;a href=&quot;http://glcf.umd.edu/data/watermask/&quot; rel=&quot;nofollow noreferrer&quot;&gt;MODIS global water mask&lt;/a&gt;, a very useful dataset at 250m resolution that allows to distinguish between dry land and water covered areas. It looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IfCf6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IfCf6.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(It doesn't cover Antarctica, but that continent doesn't contain any below sea level interior lands as seen in the first figure, so it doesn't really matter)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using the two datasets, I've calculated that the surface of dry land between 0 and -200 m of elevation correspond to $0.0065 \times 10^8 {km}^2$ (a 0.1% of Earth's surface).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Taking that into account, &lt;strong&gt;the percentage of dry land between -200 and 800 m is a 69.1% of Earth's dry surface&lt;/strong&gt;, or a 20.1% of the total Earth's surface.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;For question 2, I think your proposed interpretation is valid, and reasonable. But also other interpretations (like the total biomass mentioned in the comments) are valid. Nevertheless, as mentioned above it must refer to that &quot;99% of &lt;strong&gt;land&lt;/strong&gt; species live in &lt;strong&gt;dry land&lt;/strong&gt; between -200 and 800 m&quot; or that &quot;99% of &lt;strong&gt;all&lt;/strong&gt; species live between -200 and 800 m&quot;. Otherwise the claim is incompatible with the above mentioned fact that 15% of species live on the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A second caviat is that a large amount of species are yet to be discovered, perhaps &lt;a href=&quot;https://news.nationalgeographic.com/news/2011/08/110824-earths-species-8-7-million-biology-planet-animals-science/&quot; rel=&quot;nofollow noreferrer&quot;&gt;up to the 86% of them&lt;/a&gt;, and those will arguably be found preferentially in the less explored areas of the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I haven't seen quantitative biodiversity maps considering estimated for all known species. You will be able to validate that claim if you consider one special well studied group, like vertebrates or vascular plants. Tor those two groups, comparing the following two figures with the top one makes the &quot;99% claim&quot; perhaps reasonable, but an overwhelming majority of species don't belong to those groups, and I don't know if the biodiversity distribution would be similar.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bRlGj.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bRlGj.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;(vertebrates biodiversity map from &lt;a href=&quot;https://www.savingspecies.org/stunning-new-biodiversity-maps-show-where-to-prioritize-conservation/&quot; rel=&quot;nofollow noreferrer&quot;&gt;savingspecies.org&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zfxZD.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zfxZD.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;(vascular plants biodiversity map from &lt;a href=&quot;http://www1.biologie.uni-hamburg.de/b-online/e56/56b.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hamburg University&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If an actual number wants to be calculated based on actual data, the &lt;a href=&quot;http://biodiversitymapping.org/wordpress/index.php/download/&quot; rel=&quot;nofollow noreferrer&quot;&gt;GIS  datasets&lt;/a&gt; at &lt;a href=&quot;http://biodiversitymapping.org/wordpress/index.php/home/&quot; rel=&quot;nofollow noreferrer&quot;&gt;biodiversitymapping.org&lt;/a&gt; are a great resource.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Perhaps one argument in favour of the biomass interpretation of the claim, is that it would be a much easier and better constraint calculation.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-22T21:11:07.777" LastActivityDate="2018-03-22T21:11:07.777" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13698" PostTypeId="2" ParentId="13696" CreationDate="2018-03-22T21:47:35.113" Score="11" Body="&lt;p&gt;So meteorology is unique in that it changes depending on the scale and process. For a general taste of meteorology, I suggest &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/012732951X&quot; rel=&quot;noreferrer&quot;&gt;Wallace and Hobbes&lt;/a&gt;. You may note similarities among most of my recommendations, but that may just be a bias from my personal experience.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the most problematic elements of meteorology is atmospheric dynamics. A common resource is &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/0123848660&quot; rel=&quot;noreferrer&quot;&gt;Holton's book&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For thermodynamics, a common book used in my undergraduate studies was &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/0195099044&quot; rel=&quot;noreferrer&quot;&gt;Bohren and Albrecht&lt;/a&gt;. Although you may have experience in thermodynamics, atmospheric thermodynamics is often treated differently, with different quantities. You may recognize some of the equations used, but the variables derived are used throughout atmospheric science.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For mesoscale (medium-sized) meteorology, &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/0470742135&quot; rel=&quot;noreferrer&quot;&gt;Markowski and Richardson&lt;/a&gt; have a good book.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For atmospheric radiation, &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/0972903313&quot; rel=&quot;noreferrer&quot;&gt;Petty&lt;/a&gt; has a basic book.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In my synoptic meteorology class, we were assigned &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/1878220101&quot; rel=&quot;noreferrer&quot;&gt;this book&lt;/a&gt;, but I don't recall ever really using it. &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/019506268X&quot; rel=&quot;noreferrer&quot;&gt;This book&lt;/a&gt; looks more comprehensive (in fact, I might get it for myself).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For boundary layer meteorology, try &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/9027727694&quot; rel=&quot;noreferrer&quot;&gt;Roland Stull's book&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2018-03-22T21:47:35.113" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13699" PostTypeId="2" ParentId="10125" CreationDate="2018-03-23T00:04:30.390" Score="5" Body="&lt;p&gt;Let's first consider the scenario in the absence of free radicals that can act as catalysts of $O_3$ destruction.&#xA;In such scenario, added to the absence of UV radiation, the photolysis of ozone ($O_3 + UV → O_2 + O$) would not be possible. Therefore, the only way to destroy ozone would be by the reaction&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$O_3 + O· → 2 O_2$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the lack of UV radiation would also stop the production of atomic oxygen by photolysis, therefore only the preexisting atomic oxygen would be available for that reaction.&#xA;Then, for simplicity we can consider two extreme scenarios:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;All the atomic Oxygen forms $O_2$ and the Ozone level remains constant at the same level it has prior to the shut down of UV radiation.&lt;/li&gt;&#xA;&lt;li&gt;All the atomic Oxygen is used to destroy Ozone&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;In the second scenario the final concentration of $O_3$ will depend on the initial concentration of it and atomic oxygen. But as seen in the following image, the stratospheric concentration of atomic oxygen is much lower than the one of $O_3$, therefore the ozone levels would never fall to zero.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/L13sJ.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/L13sJ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;(Figure taken from &lt;a href=&quot;https://www.ems.psu.edu/~brune/m532/meteo532_ch7_stratospheric_chemistry.htm&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's now consider the more realistic case, on which there are other &quot;polutants&quot; that can break down ozone. The moste common ones are hydroxyl radical (OH·), nitric oxide radical (NO·), chlorine radical (Cl·) and bromine radical (Br·) (&lt;a href=&quot;https://en.wikipedia.org/wiki/Ozone_depletion&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;), and the first two are the only ones naturally occurring. Therefore, the ozone remaining from our first scenario would be reduced to zero by reactions like:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$OH + O_3 → {HO}_2 + O_2$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;or&lt;/p&gt;&#xA;&#xA;&lt;p&gt;${NO}_2 + O_3 → {NO}_3 + O_2$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Among &lt;a href=&quot;https://www.ems.psu.edu/~brune/m532/meteo532_ch7_stratospheric_chemistry.htm&quot; rel=&quot;noreferrer&quot;&gt;others&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The exact time that will take will depend on the elevation, as the abundance of ozone as well as the radicals can vary orders of magnitude trough the stratosphere. It will also depend on the exact spectrum of your &quot;sustitute Sun&quot;, as some of those reactions are also mediated by light and might not happen in the absence of light of the right wavelength.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know this answer might be disappointing, as it seem that a model would need to be run to really say how long it would take to destroy all stratospheric ozone. But still I thought would be an informative answer after 11 month without one. I hope, it motivate a better answer or the improvement of this one.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-23T00:26:29.153" LastActivityDate="2018-03-23T00:26:29.153" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13700" PostTypeId="2" ParentId="10421" CreationDate="2018-03-23T01:15:28.950" Score="6" Body="&lt;p&gt;As mentioned by Barry in the comments, you just have to substract 6 degrees of latitude to get the ring around areas were it never gets DARKER than civil twilight or darker for 24 or more hours (or 12° for nautical twilight and 18° for astronomical twilight). That would be:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&quot;Never darker than civil twilight circle&quot;: : 60° 33′ 46.7″ (orange in the figures below)&lt;/li&gt;&#xA;&lt;li&gt;&quot;Never darker than nautical twilight circle&quot;: : 54° 33′ 46.7″ (green in the figures below)&lt;/li&gt;&#xA;&lt;li&gt;&quot;Never darker than astronomical twilight circle&quot;: : 48° 33′ 46.7″ (light blue in the figures below)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;To be clear, those circles surround the places where on summer solstice there is no complete nightfall (i.e. it doesn't get completely dark according to the different twilight standards).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In turn, you can think about other set of equivalent circles where it never get BRIGHTER than a given type of twilight for at least 24 hours, those would be&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&quot;Never brighter than civil twilight circle&quot;: : 72° 33′ 46.7″ (orange dotted)&lt;/li&gt;&#xA;&lt;li&gt;&quot;Never brighter than nautical twilight circle&quot;: : 78° 33′ 46.7″ (green dotted)&lt;/li&gt;&#xA;&lt;li&gt;&quot;Never brighter than  astronomical twilight circle&quot;: : 84° 33′ 46.7″ (light blue dotted)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;To be clear again, those circles surround the places where on winter solstice there is no tace of daylight (i.e. they doesn't get any daylight according to the different twilight standards).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a map, these 6 circles, plus the Polar circle (at latitude 66° 33′ 46.7″ and in red) would look like this around the North pole&#xA;&lt;a href=&quot;https://i.stack.imgur.com/toxJC.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/toxJC.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And like this around the South Pole&#xA;&lt;a href=&quot;https://i.stack.imgur.com/enXgZ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/enXgZ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And to have a world view, in geographic projection, they would look like this&#xA;&lt;a href=&quot;https://i.stack.imgur.com/uCjlK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uCjlK.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The twilights are defined like that (i.e. Sun 6, 12, 18° below the horizon), so no corrections have to be made due to refraction or the size of the solar disk. Such corrections would only apply if you want to find the &quot;effective&quot; polar circle where the Sun would/would not be visible for 24 hours even with an horizon perfectly free of obstacles.&#xA;Due to those corrections, the polar night (at the Winter Solstice) only really &lt;a href=&quot;https://en.wikipedia.org/wiki/Polar_circle&quot; rel=&quot;nofollow noreferrer&quot;&gt;happens some 80-100 km poleward of the polar circle&lt;/a&gt;. In contrast, at the polar circle itself, the Sun can be seen even at the winter solstice.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-24T04:01:11.730" LastActivityDate="2018-03-24T04:01:11.730" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13702" PostTypeId="1" CreationDate="2018-03-23T14:04:22.030" Score="2" ViewCount="110" Body="&lt;p&gt;I was thinking if there is any power plant in Earth that generates power by sending water at depths and getting steam in return?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just some random idea:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/k7PlW.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/k7PlW.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12505" LastEditorUserId="12505" LastEditDate="2018-03-23T14:28:49.290" LastActivityDate="2018-03-24T18:13:39.367" Title="Using heat at depth to generate power" Tags="|geothermal-heat|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13703" PostTypeId="2" ParentId="13688" CreationDate="2018-03-23T14:10:24.633" Score="2" Body="&lt;p&gt;I would suggest using cdo for your purpose. At least for variables, which values are independent of the grid cell size, one can use cdo.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;cdo&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;cdo (Climate Data Operators) is a command line program to process netCDF and GRIB files. It is developed an maintained by Uwe Schulzweida and colleagues at the Max-Planck Institute for Meteorology in Hamburg, Germany. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://code.mpimet.mpg.de/projects/cdo/&quot; rel=&quot;nofollow noreferrer&quot;&gt;cdo Homepage&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://code.mpimet.mpg.de/projects/cdo/embedded/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;cdo HTML Manual&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://code.mpimet.mpg.de/projects/cdo/boards&quot; rel=&quot;nofollow noreferrer&quot;&gt;cdo Forum&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;cdo provides different operators to process your data. You can chain several operators in one command. You always start with the call of cdo. Examples:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cdo OPERATOR1 -OPERATOR2 -OPERATOR3 inputfile1.nc inputfile2.nc outputfile.nc&#xA;cdo OPERATOR1 -OPERATOR2 inputfile1.nc -OPERATOR3 inputfile2.nc outputfile.nc&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The first operator is just appended to &lt;code&gt;cdo&lt;/code&gt;. All further appended operators need to have &lt;code&gt;-&lt;/code&gt; as suffix.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;example&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Assume, we have two files (&lt;code&gt;file1.nc&lt;/code&gt; and &lt;code&gt;file2.nc&lt;/code&gt;) with some ocean data (&lt;code&gt;sst&lt;/code&gt;, &lt;code&gt;salinity&lt;/code&gt;, &lt;code&gt;u&lt;/code&gt;, &lt;code&gt;v&lt;/code&gt;, ...). We want to calculate the difference between the &lt;code&gt;sst&lt;/code&gt; of both files. This is done via&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cdo diff -selname,sst file1.nc -selname,sst file2.nc outfile.nc&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;We could do this also in four steps:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cdo selname,sst file1.nc sst_of_file1.nc&#xA;cdo selname,sst file2.nc sst_of_file2.nc&#xA;cdo diff sst_of_file1.nc sst_of_file2.nc outfile.nc&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;h1&gt;Interpolate data with cdo without considering grid cell size&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;cdo provides different operators for interpolation. &lt;code&gt;REMAPBIL&lt;/code&gt; for bilinear interpolat, &lt;code&gt;REMAPNN&lt;/code&gt; for nearest-neighbor interpolation, and so on. They are listed in the manual. I use &lt;code&gt;remapbil&lt;/code&gt; here as an example.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cdo remapbil,NEW_GRID_DEF file_old_grid.nc file_new_grid.nc&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The &lt;code&gt;file_old_grid.nc&lt;/code&gt; is your input file and &lt;code&gt;file_new_grid.nc&lt;/code&gt; is your output file. Here you find an example from my work at GitHub:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://github.com/neumannd/WorkingExamples/tree/master/bash/03_interpolate2CMAQ&quot; rel=&quot;nofollow noreferrer&quot;&gt;cdo remapbil example&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The grid definition on your input file &lt;code&gt;file_old_grid.nc&lt;/code&gt; needs to be recognized by cdo. To test, whether it is recognized you can try&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cdo griddes file_old_grid.nc&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;If it prints out the correct grid definition, then everything is fine. If not, you need to correct the definition of your lon-lat grid. Please have a look in the respective section below for details.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;code&gt;NEW_GRID_DEF&lt;/code&gt; is a file, in which the target grid is described. If your target grid is a nicely defined grid, you can write this file by hand. E.g. it could look like (copied from the HTML manual of cdo):&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;gridtype = lonlat &#xA;xsize    =   60 &#xA;ysize    =   30 &#xA;xfirst   = -177 &#xA;xinc     =    6 &#xA;yfirst   =  -87 &#xA;yinc     =    6 &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Please look for &quot;CDO grid&quot; and &quot;grid description&quot; in the &lt;a href=&quot;https://code.mpimet.mpg.de/projects/cdo/embedded/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;cdo HTML Manual&lt;/a&gt; to fine more examples and explanation on it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you don't have a nicely defined grid, you can generate your &lt;code&gt;NEW_GRID_DEF&lt;/code&gt;. This is, what I have often done, because our chemistry transport model setup needed a non-nicely defined grid. &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cdo griddes file_with_wrf_grid_definition.nc &amp;gt; NEW_GRID_DEF&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;In &lt;code&gt;file_with_wrf_grid_definition.nc&lt;/code&gt;, the model grid has to be defined and it needs to be recognized by cdo. Here you find an example from my work at GitHub:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://github.com/neumannd/WorkingExamples/tree/master/bash/02_makeGridDef&quot; rel=&quot;nofollow noreferrer&quot;&gt;cdo make grid definition&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h2&gt;How to make cdo recognize&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;cdo assumes that your file conforms with the CF Conventions (&lt;a href=&quot;http://cfconventions.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate and Forecast Conventions&lt;/a&gt;). Please have a look in the respective chapter of the CF Conventions Document to get a general description.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A working grid definition could look as follows (as ncdump output):&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;dimensions:&#xA;  time = UNLIMITED ; // (1 currently)&#xA;  lay = 1 ;&#xA;  lat = 78 ;&#xA;  lon = 62 ;&#xA;variables:&#xA;  float lat(lat, lon) ;&#xA;          lat:long_name = &quot;latitudes       &quot; ;&#xA;          lat:units = &quot;degree north    &quot; ;&#xA;          lat:var_desc = &quot;latitude (south negative)                                                       &quot; ;&#xA;          lat:cell_methods = &quot;TSTEP, LAY: mean&quot; ;&#xA;  float lon(lat, lon) ;&#xA;          lon:long_name = &quot;longitudes      &quot; ;&#xA;          lon:units = &quot;degree east     &quot; ;&#xA;          lon:var_desc = &quot;longitude (west negative)                                                       &quot; ;&#xA;          lon:cell_methods = &quot;TSTEP, LAY: mean&quot; ;&#xA;  float DATA_VAR(time, lay, lat, lon) ;&#xA;          DATA_VAR:long_name = &quot;some long var name&quot; ;&#xA;          DATA_VAR:units = &quot;some unit&quot; ;&#xA;          DATA_VAR:var_desc = &quot;some description&quot; ;&#xA;          DATA_VAR:coordinates = &quot;lat lon&quot; ;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The important aspect is that the data variable has an attribute &lt;code&gt;coordinates&lt;/code&gt;, which value contains the two lon and lat dimensional variables (I attached a second example so that it becomes clear). Additionally, the &lt;code&gt;standard_name&lt;/code&gt; and &lt;code&gt;units&lt;/code&gt; attributes should be properly set at the dimensional variables.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;dimensions:&#xA;  time = UNLIMITED ; // (1 currently)&#xA;  lay = 1 ;&#xA;  lat = 78 ;&#xA;  lon = 62 ;&#xA;variables:&#xA;  float lat_1(lat, lon) ;&#xA;          lat_1:long_name = &quot;latitudes       &quot; ;&#xA;          lat_1:standard_name = &quot;latitudes       &quot; ;&#xA;          lat_1:units = &quot;degree north    &quot; ;&#xA;          lat_1:var_desc = &quot;latitude (south negative)                                                       &quot; ;&#xA;  float lon_1(lat, lon) ;&#xA;          lon_1:long_name = &quot;longitudes      &quot; ;&#xA;          lon_1:standard_name = &quot;longitudes      &quot; ;&#xA;          lon_1:units = &quot;degree east     &quot; ;&#xA;          lon_1:var_desc = &quot;longitude (west negative)                                                       &quot; ;&#xA;  float DATA_VAR(time, lay, lat, lon) ;&#xA;          DATA_VAR:long_name = &quot;some long var name&quot; ;&#xA;          DATA_VAR:standard_name = &quot;the standard name&quot; ;&#xA;          DATA_VAR:units = &quot;some unit&quot; ;&#xA;          DATA_VAR:var_desc = &quot;some description&quot; ;&#xA;          DATA_VAR:coordinates = &quot;lat_1 lon_1&quot; ;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;h1&gt;Interpolate data with cdo with considering grid cell size&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;No idea how it works with cdo&lt;/p&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2018-03-23T14:10:24.633" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13704" PostTypeId="2" ParentId="13673" CreationDate="2018-03-23T14:59:20.590" Score="7" Body="&lt;p&gt;We are moving all of CESM to open source - in particular here is the latest version of the Community Terrestrial Systems Model (CTSM) &#xA;&lt;a href=&quot;https://github.com/ESCOMP/ctsm&quot; rel=&quot;noreferrer&quot;&gt;https://github.com/ESCOMP/ctsm&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Formerly known as CLM, CTSM includes capability to run on linux or MacOS systems.&lt;/p&gt;&#xA;" OwnerUserId="4669" LastActivityDate="2018-03-23T14:59:20.590" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13706" PostTypeId="2" ParentId="13702" CreationDate="2018-03-23T16:07:51.760" Score="5" Body="&lt;p&gt;This form of geothermal energy was investigated in Australia in the early 2000s.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A company, then called Geodynamics Australia but since renamed as &lt;a href=&quot;http://renuenergy.com.au/&quot; rel=&quot;noreferrer&quot;&gt;ReNu Energy&lt;/a&gt;, constructed a geothermal power plant and during 2013 conducted a [160 day trial of a 1 MWe pilot plant] in the Hanbanero Field near the border between South Australia and Queensland(&lt;a href=&quot;http://www.futuredirections.org.au/publication/geothermal-industry-future-australia/&quot; rel=&quot;noreferrer&quot;&gt;http://www.futuredirections.org.au/publication/geothermal-industry-future-australia/&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;The pilot plant used steam generated through an EGS (Enhanced/Engineering Geothermal System) that exploits thermal energy from hot rocks over four kilometres below ground level. Following the trial, it was concluded that it may be economically viable to supply heat energy to nearby gas production operations, but not the supply of electrical energy. No further work has been done on the project, and the company completed site environmental remediation works in 2016.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The pilot plant had many technical challenges:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;EGS (also described as a hot rock system) extracts heat from hot rocks deep in the earth and conveys it to surface where it is used to generate electricity (see Figure 1 above). This involves a heat exchange arrangement. In most EGS projects, water is pumped into an injection well where it takes on heat as it moves through fractures in hot rock, and is then extracted to surface from a production well. In the Habanero pilot plant trial, temperatures seen on surface from the production well were up to 215 degrees by the time the trial was finished – certainly demonstrating the capacity to extract heat. Another critical factor in how much electricity can be generated though is the rate at which the high temperature steam is produced. In the Habanero trial, up to 19 kg/s of flow could be sustained. This contrasts with (according to the 2014 report to ARENA) flow rates in the order of 80 to 100 kg/s that would be required for economic viability. Whereas the initial intention of the Habanero project was to create a network of man-made fractures to allow optimal rates of circulation, in actuality, fluid was circulated through a naturally occurring fault in the rock (a geological feature which was not anticipated). The challenge of establishing and optimising fluid circulation between wells might be addressed in future through fracturing techniques that have resulted from ongoing technology development in tight gas or oil wells.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the issues with developing &lt;a href=&quot;https://en.wikipedia.org/wiki/Geothermal_power_in_Australia&quot; rel=&quot;noreferrer&quot;&gt;geothermal energy in Australia&lt;/a&gt;, from deep hot rocks, is the remoteness of the potential generation sites from regions that could utilize the energy. This makes the use of such geothermal systems currently unviable.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-03-23T16:07:51.760" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13708" PostTypeId="1" CreationDate="2018-03-23T19:41:36.917" Score="6" ViewCount="1025" Body="&lt;p&gt;For an assignment I was given the question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Explain why solar radiation is neglected in atmospheric “long wave” calculations and Earth radiation is neglected in atmospheric “short wave” calculations.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I realize that the wavelengths considered to be shortwave radiation are those smaller than or equal to 4$\mu m$. And I know that we say that as wavelength increases, radiation from the Earth increases while solar radiation increases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a result of this, &lt;strong&gt;Why are the sun's long-wave radiation and the Earth's short-wave radiation neglected?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any explanation would be much appreciated!&lt;/p&gt;&#xA;" OwnerUserId="12507" LastEditorUserId="6298" LastEditDate="2018-03-25T00:59:48.613" LastActivityDate="2018-03-25T00:59:48.613" Title="Why are solar longwave and terrestrial shortwave radiations neglected in radiation balance models?" Tags="|atmospheric-radiation|energy-balance|radiation-balance|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13709" PostTypeId="2" ParentId="13708" CreationDate="2018-03-24T01:42:39.507" Score="2" Body="&lt;p&gt;It is important to keep in mind the black-body approximated radiation for the Earth and the Sun.  Notice how small the long-wave energy radiation is from the sun and how Earth's radiation peaks there.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would speculate that this question has something to do with the fact that Earth's surface is heated by solar shortwave radiation, and that Earth's lower atmosphere is heated by the Earth's surface.  It is a common misconception that the Earth feel's thermal &quot;heat&quot; (longwave) from the sun.  The Earth is instead absorbing short-wave radiation and then re-radiating that energy to the atmosphere as long-wave radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7SVVU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7SVVU.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2018-03-24T20:05:04.157" LastActivityDate="2018-03-24T20:05:04.157" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13711" PostTypeId="2" ParentId="13708" CreationDate="2018-03-24T05:32:53.310" Score="5" Body="&lt;p&gt;It is because longwave (LW) correspond to a negligible part of the solar radiation and shortwave corresponds to a negligible part of solar radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can make an experiment yourself using &lt;a href=&quot;https://astrogeology.usgs.gov/tools/thermal-radiance-calculator/&quot; rel=&quot;noreferrer&quot;&gt;NASA's Radiance calculator&lt;/a&gt;. By adjusting the parameters for Earth's and the Sun you will get the following plot of energy flux at different wavelengths&#xA;&lt;a href=&quot;https://i.stack.imgur.com/X5frZ.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/X5frZ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;(The red line is the radiation spectra of the Sun and the blue line that of the Earth)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cool thing about this tool is that you can see the actual data (or download it as a spreadsheet) and estimate the total energy flux between any range of wavelength (the area under the curve).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this case, for &lt;a href=&quot;https://en.wikipedia.org/wiki/Shortwave_radiation&quot; rel=&quot;noreferrer&quot;&gt;SW radiation&lt;/a&gt; (0.1 - 4 $\mu m$) and &lt;a href=&quot;https://en.wikipedia.org/wiki/Outgoing_longwave_radiation&quot; rel=&quot;noreferrer&quot;&gt;LW radiation&lt;/a&gt; (4 - 100 $\mu m$) you get the following numbers&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sun LW: $1.98 \times 10^7 W m^{-2} {sr}^{-1}$&lt;br/&gt;&#xA;Sun SW: $1.95 \times 10^5 W m^{-2} {sr}^{-1}$&lt;br/&gt;&#xA;Sun Total: $2.00 \times 10^7 W m^{-2} {sr}^{-1}$&lt;br/&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth LW: $1.24 \times 10^2 W m^{-2} {sr}^{-1}$&lt;br/&gt;&#xA;Earth SW: $1.82 \times 10^{-1} W m^{-2} {sr}^{-1}$&lt;br/&gt;&#xA;Earth Total: $1.23 \times 10^2 W m^{-2} {sr}^{-1}$&lt;br/&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in terms of percentages:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Sun: 99.03% SW and 0.97% LW&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Earth 0.15% SW and 99.85% LW&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That illustrate my initial point: &lt;strong&gt;LW is negligible for the Sun and SW negligible for Earth&lt;/strong&gt;. Therefore, in simple models you can ignore both solar LW and terrestrial SW.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;And why it is that way?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Well the reason is because the peak of the emissions decrease inversely proportional to temperature (according to &lt;a href=&quot;https://en.wikipedia.org/wiki/Wien%27s_displacement_law&quot; rel=&quot;noreferrer&quot;&gt;Wien's law&lt;/a&gt;), while the total power grows MUCH faster, proportional to the fourth power of the temperature (according to &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law&quot; rel=&quot;noreferrer&quot;&gt;Stefan-Boltzmann law&lt;/a&gt;). So the Sun been much hotter, produce an enormously larger amount of energy per square meter, but most of that energy is delivered in much shorter wavelength.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: It is interesting to note that despite that it is OK to neglect solar LW it is still 1580 times stronger than terrestrial LW.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-24T05:53:30.867" LastActivityDate="2018-03-24T05:53:30.867" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13713" PostTypeId="2" ParentId="8796" CreationDate="2018-03-24T12:22:25.697" Score="9" Body="&lt;p&gt;Solar wind particles directly entering the Earth's magnetosphere are not responsible for the majority of bright auroral displays. As you have found, it is magnetic reconnection that accelerates magnetospheric plasma that collides with the upper atmosphere to cause the visible aurora.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Polar rain&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The Solar wind does enter the magnetosphere directly, and travels down the field lines that have their feet poleward of the main auroral oval. This is termed the polar rain¹. The particles in the polar rain are usually too low energy and low intensity to provide visible aurora, though they do produce X-rays as the particles accelerate in the atmosphere (for example, in &lt;a href=&quot;http://solarviews.com/eng/sunpr1.htm&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt; report of a Nasa study). On occasion, the polar rain can become energetic and intense enough to generate visible emissions, unsurprisingly termed 'polar rain aurora'².&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Magnetic reconnection&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Magnetic reconnection is responsible for the displays that people usually think of as the Northern Lights. The brightest aurorae typically occur on the auroral oval around midnight Magnetic Local Time (MLT). This can be seen in the results of the current OVATION model below.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/SfUZk.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SfUZk.jpg&quot; alt=&quot;OVATION model of the northern hemisphere aurora 2018-03-24 11:35UT, courtesy NOAA.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The energetic electrons that cause the bright midnight aurora are generated by reconnection in the magnetotail, the portion of the Earth's magnetosphere that streams behind the Earth, dragged by the motion of the Solar wind (this is briefly mentioned in the NASA youtube videos linked in the question). We can tell this from the fact that the aurorae occur in a distinct oval around the pole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The bright aurorae occur near the open-closed field line boundary³, toward the closed side of the boundary. Closed field lines are those that have one foot in the northern hemisphere, follow a continuous closed path through the magnetosphere and have a second (conjugate) foot in the southern hemisphere. This means that any charged particles on these field lines must originate from within the Earth's magnetosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Conversely, the field lines accessible to charged particles from the Solar wind are the open field lines; it is along these field lines that polar rain occurs. These occur closer to the pole than the closed field lines, and form the dark area around the pole where the aurorae are not usually observed. The field lines are 'open' in the sense that they connect to the interplanetary magnetic field and are connected to the Earth at only one end, the other being open to the Solar wind.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;An historical footnote&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The idea that magnetic reconnection is the main cause of the aurorae is not a new one. I am not sure when magnetospheric sources of energetic particles, and reconnection specifically, became the dominant theory of the aurorae, but it was certainly before Dungey⁴ described the magnetospheric convection pattern in 1961.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, why is this news in the 2010s? I would suggest that it is a case where an earlier, simpler explanation has become lodged in the public consciousness long after it has passed from being the state-of-the-art. Around the turn of the 20th century, the earliest investigations into the aurorae involved physical models of the magnetosphere and the Solar wind. These &lt;a href=&quot;https://en.wikipedia.org/wiki/Terrella&quot; rel=&quot;noreferrer&quot; title=&quot;terrelas&quot;&gt;terrellas&lt;/a&gt; suggested that Solar wind directly caused the aurorae, but left investigators such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Kristian_Birkeland&quot; rel=&quot;noreferrer&quot;&gt;Kristian Birkeland&lt;/a&gt; unable to explain why the real aurorae did not occur over the pole itself, as the terrella model suggested they should. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Fairfield, D. H., and J. D. Scudder (1985), Polar rain: Solar coronal electrons in the Earth's magnetosphere, J. Geophys. Res., 90(A5), 4055–4068, doi:&lt;a href=&quot;https://doi.org/10.1029/JA090iA05p04055&quot; rel=&quot;noreferrer&quot;&gt;10.1029/JA090iA05p04055&lt;/a&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Zhang, Y., L. J. Paxton, and A. T. Y. Lui (2007), Polar rain aurora, Geophys. Res. Lett., 34, L20114, doi:&lt;a href=&quot;https://doi.org/10.1029/2007GL031602&quot; rel=&quot;noreferrer&quot;&gt;10.1029/2007GL031602&lt;/a&gt;. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;J. A. Wild et al. (2004), The location of the open-closed magnetic field line boundary in the dawn sector auroral ionosphere, Ann. Geo., 22: 3625–3639, doi:&lt;a href=&quot;https://doi.org/10.5194/angeo-22-3625-2004&quot; rel=&quot;noreferrer&quot;&gt;10.5194/angeo-22-3625-2004&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;J. W. Dungey (1961), Interplanetary Magnetic Field and the Auroral Zones, Phys. Rev. Lett. 6, 47-48, doi:&lt;a href=&quot;https://doi.org/10.1103/PhysRevLett.6.47&quot; rel=&quot;noreferrer&quot;&gt;10.1103/PhysRevLett.6.47&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="12510" LastActivityDate="2018-03-24T12:22:25.697" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13714" PostTypeId="1" CreationDate="2018-03-24T13:46:53.677" Score="4" ViewCount="60" Body="&lt;p&gt;I read a document in which the authors stated &quot;Sulfate and sulfide ( bisulfide and dihydrogen sulfide) both exist within a system just in varying proportions, and aqueous speciation is dependent on Eh/pH. If one side of the equation changes, the other will transform to balance it out&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The system they are referring to is an engineered wetland, with low amounts of labile carbon but was amended with gypsum and therefore has high sulfate concentrations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The authors have stated that in deeper zones of the wetland (5-10m), where it is fully saturated, and where oxygen penetration is minimal, aqueous bisulfide would be the main form of sulfur that exists. However, they have provided no evidence, and the carbon that exists in that zone is highly recalcitrant (meaning it is not readily degradable by sulfate reducing bacteria). So how can they say that the main form of sulfur is sulfide in this zone if the sulfate reduction process is not occurring, or very limited, due to low amounts of labile carbon? Even if it is not reacting with metals to form precipitates. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Isn't it common for sulfate to be main form of S even in anaerobic zones? The sulfate reduction process sure is usually carbon limited in high sulfate systems (e.g. marine sediments and even salt lakes). As far as I know, the Eh/pH tell you about the stability of the species, but it does not &quot;magically&quot; transform the sulfate to sulfide.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="12515" LastActivityDate="2018-03-24T13:46:53.677" Title="Sulfate reduction" Tags="|geochemistry|biogeochemistry|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13715" PostTypeId="2" ParentId="13702" CreationDate="2018-03-24T18:13:39.367" Score="1" Body="&lt;p&gt;Most operating geothermal power generators use the formation water directly, not the closed loop you suggest. That is, a single pipe brings the water/steam to the surface. The minerals in the waters make them exceptionally corrosive so expensive alloy equipment is required making the costs much higher than fossil fuels. But they are still economic in places like Iceland where any fossil fuels must be imported.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2018-03-24T18:13:39.367" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13716" PostTypeId="1" AcceptedAnswerId="13739" CreationDate="2018-03-24T22:20:16.743" Score="5" ViewCount="313" Body="&lt;p&gt;I recently noticed what appears to be common cubic formations just beneath the surface of Pectolite (&lt;a href=&quot;https://en.wikipedia.org/wiki/Larimar&quot; rel=&quot;noreferrer&quot;&gt;Larimar&lt;/a&gt;) gemstones. They quite resemble transparent sugar sprinkles. Each formation isn't perfectly cubic, and it should be noted that no two are identical. Such inclusions can be seen in both polished and unpolished stones. I was wondering what these cubic formations are made of, how/why they might be formed, and what they are formally referred to as. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Below are two images; the first being of a 15.5ct unpolished Larimar stone, and the second being a 7.4ct polished Larimar stone. Both images clearly depict the aforementioned inclusions. Based on the images provided, I would &lt;em&gt;estimate&lt;/em&gt; that the width of a single inclusion lies between 0.25mm and 0.75mm. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IqI22.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IqI22.jpg&quot; alt=&quot;15.5ct unpolished Larimar slab&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/R4TpE.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/R4TpE.png&quot; alt=&quot;7.4ct polished Larimar stone&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;P.S, Larimar is found primarily in the Dominican Republic. It is a form of Pectolite with a unique blue color caused by the copper in its composition. My question encompasses all Larimar in general, not just the images provided. My research into the subject has been unfruitful. I've found no source mentioning these inclusions, and it is exceedingly difficult to find source material on something so difficult to universally articulate. It's possible that the inclusions are Triclinic crystal systems, but why they stand out from the rest of the stone is beyond me. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.gemselect.com/gem-info/larimar/larimar-info.php&quot; rel=&quot;noreferrer&quot;&gt;One source&lt;/a&gt; states that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Calcite and hematite are often found as inclusions within deposits of Larimar stone.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Calcite and hematite may not be the the answer to my question, as the description of such inclusions from &lt;a href=&quot;https://www.gemsociety.org/article/pectolite-jewelry-and-gemstone-information/&quot; rel=&quot;noreferrer&quot;&gt;another site&lt;/a&gt; states that: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Hematite can create fern-like “red plume” patterns, calcite crystals.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="12518" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T08:58:46.733" LastActivityDate="2019-08-28T08:58:46.733" Title="What are the cubic formations found inside Larimar gemstones?" Tags="|geology|geochemistry|mineralogy|minerals|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13718" PostTypeId="1" CreationDate="2018-03-25T06:10:57.587" Score="1" ViewCount="47" Body="&lt;p&gt;I understand &lt;a href=&quot;http://www.mae.gov.nl.ca/waterres/quality/drinkingwater/dwqi.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;water quality indices&lt;/a&gt; play a fundamental role in modelling water quality as they integrate multiple water quality parameters to bring about a single dimensionless digit that represents the overall quality of water corresponding to a textual rating.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the uses of water differ and the indices are usually calculated separately. I was wondering if there is a method for determining the water quality index on a watershed basis where multiple uses of water (ecosystem, drinking, irrigation etc) are integrated.&lt;/p&gt;&#xA;" OwnerUserId="5273" LastActivityDate="2018-03-25T11:45:31.683" Title="Watershed scale water quality indices" Tags="|models|water|watershed|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13720" PostTypeId="2" ParentId="13654" CreationDate="2018-03-25T07:42:50.697" Score="3" Body="&lt;p&gt;Due to the following reasons; our world is facing water scarcity:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Climate change &lt;/li&gt;&#xA;&lt;li&gt;Unequal distribution of water &lt;/li&gt;&#xA;&lt;li&gt;population Growth &lt;/li&gt;&#xA;&lt;li&gt;Rapid urbanization &lt;/li&gt;&#xA;&lt;li&gt;Industrialization&#xA;In many countries due to the climate change the snow fall changed to the rain and flood so the water goes away instead of recharging the ground water &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="12519" LastEditorUserId="12057" LastEditDate="2018-03-26T20:07:40.450" LastActivityDate="2018-03-26T20:07:40.450" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13723" PostTypeId="2" ParentId="13654" CreationDate="2018-03-26T01:08:56.997" Score="7" Body="&lt;p&gt;You have to consider the source of water for each location.   Groundwater, for example, is a fairly abundant but non-renewable water source in some locations.  It can take a centuries to replenish.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;River water fed by mountain glaciers depends on the size of the glacier, as the glaciers shrink, meltwater decreases.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regions that depend on rainwater or snowmelt can experience water shortages when there's a low-snow winter or drought.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Water shortage depends a lot the location and the source of that regions water.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;NYCity for example depends on reservoirs upstate that are fed by rain and snow-melt, and when they started to have some shortages, which weren't uncommon during low snow years in the 80s and 90s, they began (temporarily and only during drought years) drawing water from the Hudson river, which required more filtration but it's abundant.   NYC is proud of it's tap water and the Hudson water, even if just 10% of the tap water supply for a summer here or there, wasn't very popular.    Could be worse, Los Angeles they drink filtered and purified sewage water.   Yum.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now that the &lt;a href=&quot;http://www.nydailynews.com/new-york/catskill-aqueduct-solved-nyc-water-shortage-article-1.2882468&quot; rel=&quot;noreferrer&quot;&gt;catskill aqueduct is finished&lt;/a&gt;, NYC doesn't have to draw from the Hudson during low-snow years.   Much of California also depends on enormous aqueducts, which are some of the largest construction projects in the US and perhaps somewhat obvious, they experience water shortages a lot.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With proper infrastructure, water shortages could be largely eliminated, but that's expensive and there's also border issues.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's also problematic to draw water from lakes because lakes don't necessarily fill up that fast.  Lakes are reservoirs, but can be slow to refill.   Drawing water from the great lakes, the largest fresh water source in the world outside of the large glaciers isn't a long term solution because the Great lakes don't refill very fast.   Also, if you were to draw enough water from the great lakes, that would reduce Niagara Falls' electrical generation.  (which might be secondary to water needs but just throwing that out there.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fresh water demand has largely emptied &lt;a href=&quot;https://en.wikipedia.org/wiki/Aral_Sea&quot; rel=&quot;noreferrer&quot;&gt;the Aral sea&lt;/a&gt;.   The water that kept it full has been diverted for soviet irrigation projects and the sea, since it's no longer refilling, is now nearly gone. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bottom line is that there's a finite amount of rain water and snow runoff which is the vast majority of the renewable water supply and there's a lot of demand for it, when you consider all it's used for both naturally and by man, including filling rivers and lakes, supplying the forests and natural areas, farming demands and tap water needs.  There's a huge demand.   The entire picture is complicated, but because ocean water is difficult and costly to purify and because lakes and underground sources can be depleted, there is a finite amount of readily usable water which varies year to year and that hits some regions harder than others.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2018-03-26T13:56:56.213" LastActivityDate="2018-03-26T13:56:56.213" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13724" PostTypeId="1" CreationDate="2018-03-26T03:13:17.827" Score="1" ViewCount="983" Body="&lt;p&gt;I have been learning meteorology a bit on my own, and one thing that never gets answered clearly is the relationship of pressure, temperature, and density.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I looked it up, the density of air at various temperatures varies quite a bit - if I recall, from something like 1.1 to 1.5 kg/m&lt;sup&gt;3&lt;/sup&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My confusion comes from trying to understand weather formation.  A typical text says that, for instance, heating of the earth leads to thermals that rise due to their higher temperature &lt;em&gt;and lower density&lt;/em&gt;, leading altitude increasing and to temperature dropping at the dry adiabatic lapse rate, then the moist adiabatic lapse rate, etc.  But it is always done using &quot;parcel&quot; arguments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From basic thermodynamics, heating could lead to a combination of temperature increase, pressure increase, and physical expansion (if there is no fixed container).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Specifically, the ideal gas law gives:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$PV=nRT $$&#xA;or&#xA;$$P=\frac{n}{V}T$$ (ignoring the constant of R)&#xA;or&#xA;$$P=\rho T$$where $\rho$ equals density.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Am I wrong to assume that the simplifying assumption is that, to a first order approximation, the density can't really change much about an area since a parcel of air could expand, but the whole atmosphere locally can't (since the 'parcels' all abut)?  In other words, ground heating causes temperature to rise, and thus presumably pressure, but to a negligible degree decreases density?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This would seem to imply higher pressure from heating actually leads to a net kinematic effect of driving the column of air upwards (as molecular pressure against the ground increases), where it can expand against lower pressure air above due to the fact pressure falls quickly with altitude - but there really isn't expansion or a decrease in density near the surface itself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The typical &quot;parcel lifted by a helicopter&quot; argument fails to explain how it really all holds together and actually happens, since there is no 'container' for the gas in reality.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another way to see this is in this example.  Suppose I have a hot tub in Antarctica in winter (I have one in Idaho in winter which is close enough).  The ambient temperature may be -30C or about 240K, and when I open the cover there is water at about 30C or 300K.  I can see thermals climb; the air, perhaps, is heated to 270K (being generous).  But the new air that gets sucked in and heated over the surface to 270K and then rises would immediately seem to be at higher pressure than ambient air since $$P=\rho T$$ I could even believe the kinematically more energetic air could cause an expanding 'plume' radially a bit as it rises, since the higher P and T slightly pushes out on less energetic ambient air.  But that just means $\Delta P$ is slighlty reduced to take into account the expanded volume of the plume; $\rho$ has dropped slightly, but nowhere near how fast it will drop if it gains altitude and has truly lower pressure about it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In reality, it seems:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;locally the (synoptic) pressure is close to fixed - and varies only a few percent globally at sea level;&lt;/li&gt;&#xA;&lt;li&gt;the gradient of pressure change is in the $z$ direction;&lt;/li&gt;&#xA;&lt;li&gt;local heating increases T and thus P, except to the degree that increased P allows it to form an expanding plume (which is a few percent, so second order);&lt;/li&gt;&#xA;&lt;li&gt;Really, the more energetic (kinetic) molecules have no where to go but up, what is really causing any updraft.  &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="12502" LastEditorUserId="28050" LastEditDate="2018-04-27T00:44:07.060" LastActivityDate="2018-06-26T02:21:58.833" Title="Relationship between pressure, temperature and density in meterology" Tags="|meteorology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13727" PostTypeId="1" AcceptedAnswerId="22603" CreationDate="2018-03-26T06:57:30.923" Score="5" ViewCount="102" Body="&lt;p&gt;I'd like to look into the possibility of using a Raspberry Pi and the PiCam module to detect rain, and to try to make some measurements of droplet size and rate. This could be done using an LED flash or a (modified/pulsed) laser pointer equipped with a fan-out element, synchronizing the flash/pulse with the Pi camera's electronic shutter for a &quot;freeze frame&quot; effect, followed by some Python image analysis (e.g. &lt;a href=&quot;https://pypi.python.org/pypi/PIL/1.1.6&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;code&gt;PIL&lt;/code&gt;&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is for fun, and not meant to be a quantitative rain gauge necessarily.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to better estimate the challenge, I'd like to get some feel for the distribution of sizes, speeds, and either areal rates (drops per sec per square meter) or number densities (drops per cubic meter). I can convert between various units and histograms, but I don't know where to find a good survey to understand over what ranges these can vary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See also &lt;a href=&quot;https://raspberrypi.stackexchange.com/q/76116/35753&quot;&gt;Will long-term viewing of a sunny sky hurt the Pi Camera?&lt;/a&gt; for pics of a cool Pi sky camera by @ThomasJacquin as described &lt;a href=&quot;https://raspberrypi.stackexchange.com/a/78317/35753&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt; per this &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13727/what-are-typical-ranges-of-rainfall-drop-sizes-speeds-and-areal-or-volume-dens?noredirect=1#comment25899_13727&quot;&gt;comment&lt;/a&gt; I should point out my Raspberry Pi will be within a few meters of the Earth's surface, where I can keep an eye on it.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2018-03-26T09:05:22.417" LastActivityDate="2021-07-26T11:48:21.320" Title="What are typical ranges of rainfall drop sizes, speeds, and areal or volume densities?" Tags="|meteorology|rainfall|rain|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13728" PostTypeId="1" CreationDate="2018-03-26T13:13:32.260" Score="1" ViewCount="366" Body="&lt;p&gt;In the area of atmospheric chemistry, I have learned that the heterogeneous oxidation of SO2 is one of the important pathways for sulfate formation. The reactions of SO2 oxidation in mineral, soot particles have been confirmed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;strong&gt;adsorption or uptake&lt;/strong&gt; of SO2 on the particle surface&quot; is the initial process of the transformation. I have heard that adsorption is the surface-based process of gases or ions and create a film &lt;a href=&quot;https://en.wikipedia.org/wiki/Adsorption&quot; rel=&quot;nofollow noreferrer&quot;&gt;wiki reference&lt;/a&gt;.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What's the difference between the adsorption and uptake processes?&lt;/p&gt;&#xA;" OwnerUserId="5214" LastActivityDate="2018-09-14T06:59:21.277" Title="What's the difference between uptake and adsorption of gas into aerosols" Tags="|atmosphere|atmospheric-chemistry|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13729" PostTypeId="2" ParentId="13724" CreationDate="2018-03-26T16:58:43.783" Score="1" Body="&lt;p&gt;'Locally' and 'synoptically' are conflicting adjectives. Synoptic means overall, or large horizontal scale- think thousands of kilometers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You are right on some accounts. Synoptically, pressure doesn't change much, depending on your qualitative definition of 'much.' On a percent scale or day-to-day experience, absolute temperature fluctuates more than pressure. But the gap of those fluctuations result in changes of density, leading to changes in buoyancy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The vertical momentum equation :$$\frac{\partial w}{\partial t}+(\vec{v}\cdot\nabla_H)w+w\frac{\partial w}{\partial z}=-\frac{1}{\rho}\frac{\partial P}{\partial z}- g + \nabla^2w$$ when applied to synoptic scales can be treated as approximately hydrostatic: $$\frac{\partial P}{\partial z}=-\rho g$$.&#xA;From this equation, as well as the ideal gas law, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hypsometric_equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;hypsometric equation&lt;/a&gt; may be derived.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although the vertical gradient of pressure is large, gravity is also large, which explains why the atmosphere is not lost to space and vertical motions aren't usually large in horizontal scale.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using said hypsometric equation, it can be shown that changes in vertically-averaged temperature lead to synoptic scale changes in surface pressure.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2018-03-27T13:29:40.640" LastActivityDate="2018-03-27T13:29:40.640" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="13731" PostTypeId="1" AcceptedAnswerId="13733" CreationDate="2018-03-26T20:13:37.440" Score="13" ViewCount="1045" Body="&lt;p&gt;Why does Earth have two clearly differentiated kinds of crusts, namely continental and oceanic? How did they differentiate initially and why don't they get mixed up over time? &lt;/p&gt;&#xA;" OwnerUserId="12528" LastEditorUserId="2470" LastEditDate="2018-03-27T01:35:33.643" LastActivityDate="2022-04-14T02:51:56.930" Title="Why does Earth have two kinds of crusts?" Tags="|crust|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13733" PostTypeId="2" ParentId="13731" CreationDate="2018-03-26T21:55:28.167" Score="6" Body="&lt;p&gt;First they do get slowly mixed at the plate boundaries but the mixing is minimal compared to the amount of crust there is. They do not mix easily since they have different densities, they tend to separate out when melted so most mixing is done in their solid states. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;An easy way to think of it is there is not enough continental crust to cover the entire planet so oceanic crust is filling in the gaps. A better analogy is to think of continental crust as scum on pond (or foam in a tub). The uppermost portion of the mantle and oceanic crust are basically the same thing, oceanic crust is just colder, while continental crust is different in composition it is lighter and floats on top but as I said there is not enough of it to cover the entire planet so like scum on a pond it forms clumps and gets pushed around by the underlying currents. And just like pond scum they separate out because they have different densities than the &quot;water&quot; so they collect on the surface.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="2470" LastEditDate="2018-03-27T01:36:37.117" LastActivityDate="2018-03-27T01:36:37.117" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13736" PostTypeId="2" ParentId="13654" CreationDate="2018-03-27T00:56:57.880" Score="9" Body="&lt;p&gt;I would summarize the main factors that can lead  to water scarcity in the following points:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Increase in demand&lt;/strong&gt;: As population grows, there is more overall water consumption. The rise is enhanced by the increase in life standards. For example, many countries in Africa live with a hundredth of the US water usage per capita [&lt;a href=&quot;http://chartsbin.com/view/1455&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;].&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Concentration of demand&lt;/strong&gt;: In addition to population growth, there is population densification. Due to preferential migration to large cities or already densely populated areas.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Reduction of natural reservoirs capacity&lt;/strong&gt;:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Snowpack&lt;/strong&gt;: Snow is a natural seasonal reservoir that stores water in the winter and releases it on the summer. Effectively providing water during the most needed period. Due to overall global warming &amp;quot;Northern Hemisphere spring snow cover has continued to decrease in extent (high confidence).&amp;quot; (from &lt;a href=&quot;https://www.ipcc.ch/pdf/assessment-report/ar5/syr/AR5_SYR_FINAL_SPM.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC AR5&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Glaciers&lt;/strong&gt;: Mountain glaciers can store water not only from the winter to release in summer. But from rainy years or decades to release it on the dryer years. As mountain glaciers retreat worldwide, the storage capacity is reduced, making the dry months even dryer.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Reduction of reservoirs levels&lt;/strong&gt;: Many lakes and specially groundwater reservoirs are been drain at a rate faster than the recharge rate. Therefore, they won't be able to sustain current water usage rates for too long. A classic example, as mentioned by @userLTK is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Aral_Sea&quot; rel=&quot;nofollow noreferrer&quot;&gt;Aral sea&lt;/a&gt;, formerly one of the four largest lakes in the world is now reduced to a 10% of its original size (see figure below)&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Depletion of &lt;a href=&quot;https://en.wikipedia.org/wiki/Fossil_water&quot; rel=&quot;nofollow noreferrer&quot;&gt;fossil water&lt;/a&gt; reservoirs&lt;/strong&gt;: In the same fashion that a oil well can be used up and it will never &amp;quot;refill&amp;quot;. Some groundwater reservoirs are just relics of past climates and do not recharge. Therefore, once used up, the will be extinguished forever. This is the case of the controversial &lt;a href=&quot;https://en.wikipedia.org/wiki/Silala_River&quot; rel=&quot;nofollow noreferrer&quot;&gt;manatiales de Silala&lt;/a&gt; in Bolivia or the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ogallala_Aquifer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ogallala aquifer&lt;/a&gt; in the US.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Climate change&lt;/strong&gt;: Over millenia, population and specially food production have concentrated in areas with reliable water availability (along rivers for example). Climate change can redistribute rainfall and reduce availability in some areas and increase it in others. And due to the fact that is difficult and costly to relocate the population, it is likely that there will some areas with more population than what can be sustained with the available water resources.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Reduced water quality&lt;/strong&gt;: &lt;a href=&quot;https://earthscience.stackexchange.com/a/13741/595&quot;&gt;As @JanDoggen rightly pointed&lt;/a&gt;, it is not often the case that people drink the water straight out of rivers. Usually, filtering and cleaning is required. And as the pollution levels increase on rivers and lakes (due to industry, sewage, etc.). It is becoming more expensive and difficult to actually use the available water for agriculture and human consumption.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PA39X.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PA39X.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;A comparison of the Aral Sea in 1989 (left) and 2014 (right) [Originally from Wikipedia commons &lt;a href=&quot;https://en.wikipedia.org/wiki/Aral_Sea#/media/File:AralSea1989_2014.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;]&lt;/p&gt;&#xA;&lt;p&gt;Rainwater seem to us an endless resource, in the same way a few hundred years ago the forests or the whales seemed endless. But if we consider that an US citizen &lt;a href=&quot;https://www.statista.com/statistics/263156/water-consumption-in-selected-countries/&quot; rel=&quot;nofollow noreferrer&quot;&gt;uses in average about 1580 &lt;span class=&quot;math-container&quot;&gt;$\text{m}^3$&lt;/span&gt; of water a year&lt;/a&gt;, and that the &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13200/how-much-rain-falls-on-the-earth-each-year/13204#13204&quot;&gt;total amount of rain that fall on land in the entire world every year is about &lt;span class=&quot;math-container&quot;&gt;$10^{14} \text{m}^3$&lt;/span&gt;&lt;/a&gt; (100,000 billion &lt;span class=&quot;math-container&quot;&gt;$\text{m}^3$&lt;/span&gt;). Then, you can easily calculate that all the rain in the world (even if we could use it all), would be enough only to sustain about 70 billion US-type-humans, a number that is not that far off the &lt;a href=&quot;https://en.wikipedia.org/wiki/Projections_of_population_growth&quot; rel=&quot;nofollow noreferrer&quot;&gt;11.2 billion we are supposed to be by 2100&lt;/a&gt;. And consider that we should leave &amp;quot;some water&amp;quot; for other animals and wild plants too.&lt;/p&gt;&#xA;&lt;p&gt;Then, recognizing that rainfall is not endless compared with the world's population needs. And acknowledging the fact that we don't have enough storage and/or transport capacity to use much of the rain, as it happens to falls during storms when we don't need it or in faraway places. Then it should become more clear why it might become tricky to supply water to everyone in the future. Specially for:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Cities in dry areas and with growing population&lt;/li&gt;&#xA;&lt;li&gt;Or cities that rely in glaciers/snow to get a reliable summer water supply&lt;/li&gt;&#xA;&lt;li&gt;Or cities draining lakes/groundwater faster than it recharge&lt;/li&gt;&#xA;&lt;li&gt;Or cities using fossil water.&lt;/li&gt;&#xA;&lt;li&gt;Or cities currently using all their renewable water resources AND likely to experience dryer climate in the future.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Among others.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="595" LastEditDate="2021-01-30T17:00:52.133" LastActivityDate="2021-01-30T17:00:52.133" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="13737" PostTypeId="2" ParentId="3176" CreationDate="2018-03-27T01:19:35.627" Score="8" Body="&lt;p&gt;The effectiveness of such shelters against pyroclastic flows have been wonderfully discussed by user889. However, I understand that &lt;strong&gt;those shelters were never intended to protect against pyroclastic flows&lt;/strong&gt;, but from &lt;strong&gt;pyroclastic fall&lt;/strong&gt;, a completely different threat, on which volcanic debris referred as &lt;a href=&quot;https://en.wikipedia.org/wiki/Tephra&quot; rel=&quot;nofollow noreferrer&quot;&gt;pyroclasts and volcanic bombs&lt;/a&gt; fall on the ground after been ejected in a volcanic eruption. This does not happen in company of a high temperature and high speed cloud of volcanic ejecta, as it is the case for &lt;a href=&quot;https://en.wikipedia.org/wiki/Pyroclastic_flow&quot; rel=&quot;nofollow noreferrer&quot;&gt;pyroclastic flows&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That should be obvious from the fact that those shelters are open and don't provide isolation from the exterior (only protection against falling stuff), a clear sign that they were never intended to protect from pyroclastic flows.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact, on that devastating 1902 eruption of Mount Pelée mentioned by user889, there were 30,000 casualties and only two survivors. The only one of them that was in the center of the city &lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Pel%C3%A9e&quot; rel=&quot;nofollow noreferrer&quot;&gt;survived because he was in a poorly ventilated, dungeon-like jail cell&lt;/a&gt;, an experience that should serve as a guide of how a pyroclastic flow shelter should look, and that's nothing like the one in the picture.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-27T15:09:32.093" LastActivityDate="2018-03-27T15:09:32.093" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13738" PostTypeId="1" CreationDate="2018-03-27T05:33:53.367" Score="5" ViewCount="108" Body="&lt;p&gt;I have been tasked with homogenizing a catalog of events obtained from the USGS website, however, the data is a mix of different type of magnitude measures. How do I convert the different type of magnitude to moment magnitude and what do they depend on? Is it a pure empirical relationship?&lt;/p&gt;&#xA;" OwnerUserId="8363" LastActivityDate="2018-03-27T05:33:53.367" Title="Conversion of body wave magnitude to moment magnitude" Tags="|earthquakes|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13739" PostTypeId="2" ParentId="13716" CreationDate="2018-03-27T06:02:05.013" Score="9" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Calcite and hematite may not be the the answer to my question&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Hematite is not the answer, but calcite is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The inclusions are not cubic, they are rhombohedral. This is precisely how calcite looks like.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;but why they stand out from the rest of the stone is beyond me. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Because calcite is a translucent mineral, and pectolite is not. You can drop some vinegar on the inclusions and you will see that they fizz a bit - this is how calcite reacts to acid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can read this for some more information:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.openaccessjournals.siftdesk.org/articles/full-text/X-ray-Photoelectron-Spectroscopy-study.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.openaccessjournals.siftdesk.org/articles/full-text/X-ray-Photoelectron-Spectroscopy-study.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-03-27T06:02:05.013" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13740" PostTypeId="1" AcceptedAnswerId="13742" CreationDate="2018-03-27T13:08:00.743" Score="7" ViewCount="3163" Body="&lt;p&gt;The EarthSky article &lt;a href=&quot;http://earthsky.org/earth/great-pacific-garbage-patch-bigger-than-thought&quot; rel=&quot;noreferrer&quot;&gt;Great Pacific Garbage Patch now 3 times size of France&lt;/a&gt; links both to the newly published article in Scientific Reports &lt;a href=&quot;https://www.nature.com/articles/s41598-018-22939-w&quot; rel=&quot;noreferrer&quot;&gt;Evidence that the Great Pacific Garbage Patch is rapidly accumulating plastic&lt;/a&gt; and to the YouTube video of one of the authors &lt;a href=&quot;https://www.youtube.com/watch?v=VxMATP5oRx4&quot; rel=&quot;noreferrer&quot;&gt;Boyan Slat - The New Picture of the Great Pacific Garbage Patch (2018)&lt;/a&gt;, which discusses both data collection and analysis, and the possibility and scope of potential cleanup efforts of a huge patch of garbage within the &lt;a href=&quot;https://en.wikipedia.org/wiki/North_Pacific_Gyre&quot; rel=&quot;noreferrer&quot;&gt;North Pacific Subtropical Gyre&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Near the end of the video, after &lt;code&gt;07:00&lt;/code&gt; is shown a very large structure being welded. It's been humorously named Boomy McBoomFace in reference to the &lt;a href=&quot;https://www.youtube.com/watch?v=VxMATP5oRx4&quot; rel=&quot;noreferrer&quot;&gt;RRS Sir David Attenborough&lt;/a&gt; story and the UAV &lt;a href=&quot;https://en.wikipedia.org/wiki/Boaty_McBoatface&quot; rel=&quot;noreferrer&quot;&gt;Boaty McBoatface&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this boom part of a subsequent garbage collection experiment, or a cleanup prototype, or something else?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Click the screen shots below for full size display:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Tslfc.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Tslfcm.jpg&quot; alt=&quot;Boyan Slat Great Pacific Garbage Patch (2018)&quot;&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/hAZIk.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hAZIkm.jpg&quot; alt=&quot;Boyan Slat Great Pacific Garbage Patch (2018)&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Ti9o9.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ti9o9m.jpg&quot; alt=&quot;Boyan Slat Great Pacific Garbage Patch (2018)&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2018-03-28T12:19:19.623" Title="What is Boomy McBoomFace?" Tags="|ocean|oceanography|pollution|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13741" PostTypeId="2" ParentId="13654" CreationDate="2018-03-27T13:16:33.823" Score="11" Body="&lt;p&gt;What I miss in the other answers is &lt;em&gt;water quality&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even is there is sufficient water available it is often of insufficient quality  for the purpose you want it for:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;We often don't drink straight out of rivers&lt;/li&gt;&#xA;&lt;li&gt;We don't irrigate with salt water&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So you need to spend effort to prepare it for use. This adds to the experience of shortage.&lt;/p&gt;&#xA;" OwnerUserId="595" LastActivityDate="2018-03-27T13:16:33.823" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13742" PostTypeId="2" ParentId="13740" CreationDate="2018-03-27T13:22:46.793" Score="12" Body="&lt;p&gt;The boom&lt;sup&gt;*&lt;/sup&gt; is a cleanup prototype. &lt;a href=&quot;https://www.theoceancleanup.com/milestones/north-sea-prototype/&quot; rel=&quot;noreferrer&quot;&gt;From the OceanCleanup website&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Ocean Cleanup deployed a 100 meter-long barrier segment in the North Sea, 23 km off the coast of The Netherlands on the 22nd of June 2016.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;OBJECTIVE AND SET-UP&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;To investigate the durability of our design, we deployed a system segment in the North Sea. At this test site, conditions are more severe than those in the Pacific Ocean, due to the North Sea's strong tidal currents, and the test site's short, steep wave patterns.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The objective of the North Sea prototype was twofold;&lt;/p&gt;&#xA;  &#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;Test the boom design on a small-scale for survivability in extreme conditions&lt;/li&gt;&#xA;  &lt;li&gt;Gaining experience as an organization in the ocean deployment of a cleanup array &lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;  &#xA;  &lt;p&gt;FINDINGS&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;During an inspection of the North Sea prototype in August, we noticed the two outermost air chambers were bent out of shape. Thanks to underwater footage we were quickly able pinpoint the cause; shackles had disconnected from the mooring, which increased the forces on the ones remaining as well as the floater. After our diagnosis, we continued to closely observe the situation and decided to take the barrier back to shore after close to two months.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The design has changed since (bottom of page).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These Youtube fragments have some more shots: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=_vRU51BeprM&quot; rel=&quot;noreferrer&quot;&gt;Video 1&lt;/a&gt;&lt;br /&gt;&#xA;&lt;a href=&quot;https://www.youtube.com/watch?v=rOxkq9O0TQ4&quot; rel=&quot;noreferrer&quot;&gt;Video 2 (Dutch)&lt;/a&gt;&lt;br /&gt;&#xA;&lt;a href=&quot;https://www.youtube.com/watch?v=Ef2uey7Nuqk&quot; rel=&quot;noreferrer&quot;&gt;Video 3&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That last video goes into detail about it's design and later versions. The comments state that &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the new North Sea tests are aimed at assessing two variations of floater-screen connections as well as the application of antifouling on the screen&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;* A long pole, often heavy, e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Boom_(sailing)&quot; rel=&quot;noreferrer&quot;&gt;along the foot of a sail&lt;/a&gt;. In this case, sheets/screens are hanging down from it.&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="595" LastEditorUserId="595" LastEditDate="2018-03-27T17:52:39.193" LastActivityDate="2018-03-27T17:52:39.193" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13743" PostTypeId="1" CreationDate="2018-03-27T16:23:46.350" Score="1" ViewCount="110" Body="&lt;p&gt;Would they move towards the Equator/Poles? Stay in the same place?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What about if the Earth was rotating 10% slower?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a rotation speed for Earth which will lead to 4 wind belts instead of 3 ?&lt;/p&gt;&#xA;" OwnerUserId="12442" LastActivityDate="2018-03-27T16:23:46.350" Title="What would happen to the Subtropical Ridge/Horse latitudes and Polar front if the Earth was rotating 5% faster?" Tags="|atmosphere|wind|atmosphere-modelling|earth-rotation|" AnswerCount="0" CommentCount="11" ContentLicense="CC BY-SA 3.0" />
  <row Id="13744" PostTypeId="1" AcceptedAnswerId="13746" CreationDate="2018-03-27T18:27:47.493" Score="13" ViewCount="403" Body="&lt;p&gt;To start life there has to be &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{Solar energy + 6CO2 + 6H2O -&amp;gt; C6H12O6 (sugars) + 6O2}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$C_6H_{12}O_{6} + O_2 \longrightarrow H_2O + {CO}_2 + \text{Energy}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to start this cycle, life needs &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt;.&#xA;&lt;strong&gt;Where did the &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; came from?&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$C + O_2 + \text{Hot temperature in the Earth} \longrightarrow {CO}_2$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Volcanoes erupt &lt;span class=&quot;math-container&quot;&gt;${CO}_2 \longrightarrow {CO}_2$&lt;/span&gt; in the Atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this the answer?&lt;/p&gt;&#xA;" OwnerUserId="12538" LastEditorUserId="6031" LastEditDate="2019-04-09T01:32:27.527" LastActivityDate="2022-02-18T19:42:01.250" Title="How did CO₂ originate on Earth before there was life?" Tags="|geology|volcanology|paleoclimatology|atmospheric-chemistry|co2|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="13746" PostTypeId="2" ParentId="13744" CreationDate="2018-03-27T19:28:38.810" Score="16" Body="&lt;p&gt;The answer is &lt;strong&gt;Volcanos&lt;/strong&gt;. There might be other inorganic processes capable to produce $\text{CO}_2$, but on Earth, the main inorganic source of $\text{CO}_2$ are volcanoes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In some period of Earth's history, there is evidence of large glaciations events, some of them are thought to have been triggered by the lack of $\text{CO}_2$ (like the &lt;a href=&quot;https://en.wikipedia.org/wiki/Snowball_Earth&quot; rel=&quot;noreferrer&quot;&gt;Snowball Earth&lt;/a&gt; and Permo-carboniferous glaciations), and volcanoes are with no doubt the main candidate to have been responsible of restoring the warm climate by feeding large amounts of $\text{CO}_2$ into the atmosphere over millions of years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\text{CO}_2$ is an important component of rocky planets, but it is mostly dissolved (in large quantities) in the magma that exist (or once existed) in the interior of such planets. However, when the magma rises close to the surface, the drop in pressure reduce the solubility of $\text{CO}_2$ and it form bubbles of gaseous $\text{CO}_2$, that can then be expelled into the atmosphere trough volcanic eruptions, that in addition to teprha, and rocks include large amounts of &lt;a href=&quot;https://en.wikipedia.org/wiki/Volcanic_gas&quot; rel=&quot;noreferrer&quot;&gt;volcanic gases&lt;/a&gt; of which $\text{CO}_2$ is one of the main components.&#xA;Probably that process of exsolution of $\text{CO}_2$ from hot molten rocks was happening even before the existence of volcanoes as we know them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same process happened once in Mars and Venus, whose atmospheres are composed mostly by $\text{CO}_2$ (&lt;a href=&quot;https://en.wikipedia.org/wiki/Mars#Atmosphere&quot; rel=&quot;noreferrer&quot;&gt;96%&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Venus#Atmosphere_and_climate&quot; rel=&quot;noreferrer&quot;&gt;96.5%&lt;/a&gt; respectively), suggesting that abundant $\text{CO}_2$ was also present in the early Earth's atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Currently, it is estimated that volcanoes input to the atmosphere about 100 million tons of carbon in average per year in the form of $\text{CO}_2$, as illustrated by this NASA figure of the Carbon cycle:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pR1vq.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pR1vq.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;(Originally from &lt;a href=&quot;https://www.nasa.gov/topics/nasalife/features/globe-workshop.html&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see that many processes move carbon around, but the main reservoir by far is the crust, and that reservoir is tiny compared with all the $\text{CO}_2$ stored deeper in the Earth's interior.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, in addition to be required by photosynthesis, $\text{CO}_2$ is part of the Earth's thermostat, that together with the &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonate%E2%80%93silicate_cycle&quot; rel=&quot;noreferrer&quot;&gt;silicate weathering&lt;/a&gt; have been key to keep the Earth's temperature in the range of liquid water. Arguably another very important need for the existence of life as we know it.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-27T19:36:53.767" LastActivityDate="2018-03-27T19:36:53.767" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13747" PostTypeId="1" AcceptedAnswerId="13748" CreationDate="2018-03-27T20:33:41.577" Score="4" ViewCount="17074" Body="&lt;p&gt;What is the distance between the tropic of cancer and the tropic of capricorn here on Earth?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now this would seem like I could simply google the answer to it and know the exact distance in miles (please provide imperial units) but I have been researching this and cant find an answer... I also don't know how to do the calculations myself so, yeah. Providing a number is definitely not what I am wanting, I would rather be told a bit more information that would allow me to fact-check your answers by doing some simple addition (like how big a degree is and how many degrees there are total (though I can probably find the size of degrees on google).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am specifically talking about when you follow the curvature of the earth.&lt;/p&gt;&#xA;" OwnerUserId="12542" LastEditorUserId="11908" LastEditDate="2019-03-04T00:36:02.353" LastActivityDate="2022-09-24T14:19:32.313" Title="What is the distance between the tropics?" Tags="|geography|astronomy|gis|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13748" PostTypeId="2" ParentId="13747" CreationDate="2018-03-28T02:00:26.653" Score="8" Body="&lt;p&gt;Both the tropics of &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropic_of_Capricorn&quot; rel=&quot;noreferrer&quot;&gt;Capricorn&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropic_of_Cancer&quot; rel=&quot;noreferrer&quot;&gt;Cancer&lt;/a&gt; are 23.43692 degrees from the equator. So the angular distance between the two is 46.8738 degrees (2 x 23.437) of latitude. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One &lt;a href=&quot;https://en.wikipedia.org/wiki/Nautical_mile&quot; rel=&quot;noreferrer&quot;&gt;nautical mile&lt;/a&gt; is defined as one minute of latitude. This is equivalent to one 1/60 of a degree.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, the distance between the tropics, along the surface of the earth is 60 x 46.8738 = 2812.4304 minutes of latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, one nautical mile is 1.852 km and 1.1508 miles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, 2812.43 minutes of latitude is 5208.6 km or 3236.5 miles&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-03-28T02:00:26.653" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13749" PostTypeId="2" ParentId="13747" CreationDate="2018-03-28T02:23:33.047" Score="11" Body="&lt;p&gt;Let's start by the quick rule of thumb, I'll follow the way I do it mentally as I think the mnemonics I use could help you too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, the tropics are at 23.5° of latitude. And remembering that the original definition of meter is &quot;A ten-millionth of an Earth's quadrant&quot;, it means the perimeter of Earth is 40,000 km, that consist on 360° of latitude, then:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$1^\circ = \frac{40,000 \, km}{360^\circ}= 111.11 \, km/^\circ$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, the distance between the tropics in a first approximation would be&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\text{Distance} = 2 \times 23.5^\circ \times 111.1 \, km/^\circ = 5221.7 \, km$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now there are a few sources of error in this calculation. First, the actual latitude of the tropics is &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropic_of_Cancer&quot; rel=&quot;noreferrer&quot;&gt;23.43692°&lt;/a&gt; (or 23°26′12.9″). Second, the perimeter of Earth is not exactly 40,000 km (it is &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth&quot; rel=&quot;noreferrer&quot;&gt;40,075.017 km along the equator and 40,007.86 km along a meridian&lt;/a&gt;). And third, Earth is not a sphere, therefore not all the degrees of latitude cover the same distance. Taking all those factors into account &lt;strong&gt;the actual distance is 5,185.9 km&lt;/strong&gt; (Calculated using a GIS software).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want more accuracy than a few hundred meters, you have to specify the date, because the actual latitude of the tropics &lt;a href=&quot;https://en.wikipedia.org/wiki/Axial_tilt&quot; rel=&quot;noreferrer&quot;&gt;oscillates between 22.1 and 24.5 degrees&lt;/a&gt; on a 41,000-year cycle. And it is currently changing at a rate of about 0.5 arc seconds of latitude per year, that translates in a displacement of about 14 meters every year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NOTE: To make the answer more readable to everyone I decided to keep it in metric units (it also makes sense for the mnemonics I use to derive the length of a degree of latitude), so I leave the transformation to imperial units to you.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-03-28T02:37:05.267" LastActivityDate="2018-03-28T02:37:05.267" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13750" PostTypeId="1" CreationDate="2018-03-28T05:21:23.123" Score="7" ViewCount="220" Body="&lt;p&gt;This is probably a very easy question to answer but how are the USGS maps showing ground water locations mapped? Is it a guy going around taking core samples? Or is it done using satellites and aircraft? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also related, how quickly do these flows change? Is taking measurements once a year fast enough or does it need to be updated daily? &lt;/p&gt;&#xA;" OwnerUserId="12545" LastEditorUserId="111" LastEditDate="2018-03-28T13:47:22.103" LastActivityDate="2018-03-28T21:52:48.783" Title="How is ground water mapped?" Tags="|groundwater|underground-water|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13752" PostTypeId="2" ParentId="13740" CreationDate="2018-03-28T12:19:19.623" Score="6" Body="&lt;p&gt;Jan Doggen's answer identifies some sources that tell a bit more about Boomy itself, so I'd like to address overall what a boom actually is in this context, and make an educated guess about the purpose of Boomy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A boom, in this context, is a large floating device intended to surround or block an area of water, keeping surface contaminants either in or out (depending on the application). Most commonly they are used in isolating oil spills, or protecting sensitive locations from oil. Oil floats on water, and a floating boom creates a surface barrier which effectively blocks the oil from spreading. &lt;a href=&quot;https://response.restoration.noaa.gov/oil-and-chemical-spills/oil-spills/spill-containment-methods.html&quot; rel=&quot;noreferrer&quot;&gt;This page&lt;/a&gt; from the National Oceanic and Atmospheric Administration (NOAA), a division of the United States government, explains the various types of booms commonly used in environmental cleanup.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some excerpts from the page:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Booms are floating, physical barriers to oil, made of plastic, metal, or other materials, which slow the spread of oil and keep it contained.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;...&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;There are three main types of boom. Hard boom is like a floating piece of plastic that has a cylindrical float at the top and is weighted at the bottom so that it has a &quot;skirt&quot; under the water. If the currents or winds are not too strong, booms can also be used to make the oil go in a different direction (this is called &quot;deflection booming&quot;). Sorbent boom looks like a long sausage made out of a material that absorbs oil. If you were to take the inside of a disposable diaper out and roll it into strips, it would act much like a sorbent boom. Sorbent booms don't have the &quot;skirt&quot; that hard booms have, so they can't contain oil for very long. Fire boom is not used very much. It looks like metal plates with a floating metal cylinder at the top and thin metal plates that make the &quot;skirt&quot; in the water. This type of boom is made to contain oil long enough that it can be lit on fire and burned up.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;With that in mind, and considering the context of Boomy McBoomFace having something to do with the Pacific garbage patch, I think it is safe to theorize that Boomy is being designed to help collect garbage floating at the surface in a similar manner to how the booms described above collect/block oil.&lt;/p&gt;&#xA;" OwnerUserId="12540" LastActivityDate="2018-03-28T12:19:19.623" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13753" PostTypeId="2" ParentId="13750" CreationDate="2018-03-28T13:46:57.447" Score="2" Body="&lt;p&gt;USGS conducts regular survey in over 20000 wells across the United States. The frequency of data collection depends on the site with around 7000 providing daily data. For some of those wells (currently, 3777 groundwater sites) daily statistics are provided. An increasing number of wells are providing real time (updated every 15 or 30 min) data. &lt;a href=&quot;https://i.stack.imgur.com/b20I2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/b20I2.png&quot; alt=&quot;USGS wells&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://groundwaterwatch.usgs.gov/default.asp&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can visualize the daily changes using this &lt;a href=&quot;https://groundwaterwatch.usgs.gov/AnimateAWL.asp&quot; rel=&quot;nofollow noreferrer&quot;&gt;animation&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Go to &lt;a href=&quot;https://waterdata.usgs.gov/nwis/gw&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://waterdata.usgs.gov/nwis/gw&lt;/a&gt; for  information as well as the ability to get the data directly from the source.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2018-03-28T13:46:57.447" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13755" PostTypeId="1" AcceptedAnswerId="13768" CreationDate="2018-03-28T14:39:34.483" Score="2" ViewCount="568" Body="&lt;p&gt;I am a high school student, my question is about the collision between the Indian Plate and the Eurasian Plate. When this happens what happens to the area of the Asian continent. Does it increase or decrease? Also, south Asia gets Monsoon rains, is this an effect of this collision?&lt;/p&gt;&#xA;" OwnerUserId="12547" LastEditorUserId="11908" LastEditDate="2019-04-06T20:03:57.077" LastActivityDate="2019-04-06T20:03:57.077" Title="Movements of the tectonic plates - collison between Indian Plate &amp; Eurasian Plate" Tags="|geology|plate-tectonics|continental-rifting|lithosphere|orography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13758" PostTypeId="2" ParentId="13750" CreationDate="2018-03-28T21:52:48.783" Score="2" Body="&lt;p&gt;Groundwater data are collected from wells, as described in arkia's answer. I'll amplify on that answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The driller or geologist describes the type of sediment encountered when drilling a well. Sometimes sediment samples are collected for analysis of grain size. Core samples aren't typically collected but may be for special studies. The type of sediment encountered during drilling gives a good idea as to whether a productive groundwater aquifer or the most productive zone in an aquifer is encountered. In addition the sediment samples can be used to determine the best type of well-screen to install.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A simple pumping test is usually performed to determine how much water the well will yield and the type of pump to install. This gives basic information on the aquifer (zone of productive groundwater) but sometimes more sophisticated pump tests are performed to determine the aquifer properties.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The USGS or other organization takes this information and geologic maps and maps out the extent of aquifers. Often more than one aquifer is encountered at a particular location and the aquifers are separated by impermeable sediments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The water level in wells within an aquifer are used to map out groundwater flow directions. Groundwater flow is almost always much slower than surface streams because the groundwater is percolating between the sediment grains. The groundwater level usually changes very slowly, except in some very shallow wells. Daily measurements are usually more than enough and many wells are measured manually less frequently, monthly, quarterly, or yearly, or only now and then. It depends on whether you are interested in seasonal variation or just the general trends.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2018-03-28T21:52:48.783" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13759" PostTypeId="1" AcceptedAnswerId="13780" CreationDate="2018-03-28T22:08:13.357" Score="4" ViewCount="2587" Body="&lt;p&gt;Areas where the buildings are built on top of a deep layer of loose sediments are widely recognised as being more prone to earthquake damage (all else being equal) than areas where the bedrock is shallow and building foundations can easily be dug down to it, because the loose sediment cover amplifies the vibrations from earthquakes, increasing the amount of damage they cause.  Why is this?  Intuitively, one would expect that, since the vibrations from an earthquake originate in the bedrock or deeper, buildings bolted directly to bedrock would be the worst-affected, and having a thick sediment layer would dampen the vibrations considerably.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So why do soft sediments amplify earthquake vibrations, when one would expect the opposite effect?&lt;/p&gt;&#xA;" OwnerUserId="12549" LastActivityDate="2018-03-30T17:44:19.493" Title="Why do loose, soft soils amplify earthquake vibrations rather than dampening them?" Tags="|earthquakes|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13761" PostTypeId="1" AcceptedAnswerId="13772" CreationDate="2018-03-29T00:45:42.543" Score="2" ViewCount="44" Body="&lt;p&gt;e.g. Something like &lt;a href=&quot;http://www.lightningsafety.noaa.gov/fatalities/fatalities17.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;, but for historical years (preferably covering 1980-2007, since the NWS detailed lists only start from 2008). Location of strike, victim name, where the victim was at (under tree, out on open water, at beach), etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If such a resource does not exist, then what's the next best thing? All the archived meteoroepidemiology (yes I know that's not a word) data I've been able to find is limited to overall numbers of lightning deaths by state/on a national basis.&lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2018-03-29T16:05:05.797" Title="Where can I find detailed historical breakdowns of U.S. lightning fatalities on a year-by-year basis?" Tags="|meteorology|statistics|lightning|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13762" PostTypeId="2" ParentId="13654" CreationDate="2018-03-29T02:19:46.597" Score="1" Body="&lt;p&gt;Most of the underlying causes of water shortages have been noted by others, but there are a few issues that need to be highlighted: the primary use of water is Agriculture. As populations advance and develop tastes for Western food, much greater pressure is put on the land to produce more. Certain crops like maize and cotton are water hungry. Even the best quality soils have only a certain water retaining capacity. Artificial fertilizers are added,usually in a greater concentration than is necessary for plant growth. Gradually the soil becomes burnt out or salinated. Any water applied to such soils will flow off the land and contaminate lakes (Lake Erie for example) or rivers. Thus large amounts of water become useless for other uses (Industry or Drinking)&lt;/p&gt;&#xA;" OwnerUserId="12551" LastActivityDate="2018-03-29T02:19:46.597" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13763" PostTypeId="2" ParentId="13759" CreationDate="2018-03-29T04:01:16.840" Score="4" Body="&lt;p&gt;I think there are a few more options than bedrock/loose.  But I owned a house 3 miles from the San Andreas fault, and a geophysical engineer explained it to me like this after telling me earthquake insurance would be a waste of money.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The worst situation is landfill, like the Marina district in San Francisco that took much of the brunt of the 89 quake.  That is just loose sand and gravel, and when shaken it acts like a liquid - in fact, they call it liquefication.  The foundation shifts and sinks in it, like if you had a jar of sand and gravel and put a heavy rock on top and shook it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, if you are on bedrock - or something tightly bound above it (like Franciscan shale), you get all the shaking transmitted, but the earth stays in place under and around the foundation.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earthquake damage can happen a few ways: from shaking up and down as well as sideways.  The Mendocino quake in the 90s (I think) had more side-to-side movement than ever seen before, and house held together but slid off their foundations.  After that they upped the degree to which house are bolted to the foundation to avoid lateral shifts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not sure soft soil 'amplifies' the shaking.  There are a bunch of failure modes in buildings: they can come off the foundation; the foundation can shift and sink; the shaking can cause framing to collapse (which is why they put in shear walls); etc.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Incidentally, wood structures often do better because they can flex.  You'll never see a real brick house being built in a seismic zone anymore.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the end, it is about making the building live through the accelerations, and the hardest thing to deal with is loose soil that itself moves and flows under the structure.&lt;/p&gt;&#xA;" OwnerUserId="12502" LastActivityDate="2018-03-29T04:01:16.840" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13765" PostTypeId="2" ParentId="13564" CreationDate="2018-03-29T04:12:27.400" Score="1" Body="&lt;p&gt;Well, I think if it starts at T=30, and the dew point is T=15, then once it has dropped 15 degrees clouds will start to form.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The DALR is about 10 degrees/km.  SO, first, I think you need to solve for the altitude at which T will have dropped from 30 to 15.&lt;/p&gt;&#xA;" OwnerUserId="12502" LastActivityDate="2018-03-29T04:12:27.400" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13766" PostTypeId="2" ParentId="13400" CreationDate="2018-03-29T04:39:59.490" Score="0" Body="&lt;p&gt;Take a look at this: &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth%27s_atmosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth%27s_atmosphere&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see a large spike in CO2 beginning with the Industrial Revolution.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, the earth has natural cycles. But this is a very rapid change.  And, we know that coincident with this, (1) the population grew a lot on earth, and (2) humans did a lot of things (mostly burning fossil fuels, but also burning wood, deforestation, out-gassing from coal seams, etc.).  We can, in fact, estimate the amount of CO2 production caused by humans by looking at oil and coal production - and the amount line up between what we probably have produced and how much we see.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And don't forget other gases are even more powerful (like methane).  A large part of that comes from agriculture, particularly meat for human consumption.  Animals that eat grasses can't digest the grass.  Rather, they are really walking fermentation units, with bacteria that breaks down cellulose - which the animal can digest - but which give off methane as a side-product.  So another approach is to use what economists call &quot;instrumental variables&quot;: by looking at global GDP, for example, as a proxy for human 'production', we can see that changes in these gases has a high correlation with human activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing to note is that it only takes a small CO2 (or other greenhouse gas) change to drive a big temperature change.  CO2 is only a few hundred parts per million of the atmosphere; methane is even less.  The 'natural' greenhouse gases keep earth as warm as it is to allow life as we know it (by about 30 degrees Celsius) by reabsorbing long-wave radiation from the surface (hence the name greenhouse gases).  SO, it only take a small change in those to drive a relatively large effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;People often don't know that.  I often compare it to 'sterile procedure' in medicine.  You won't get a surgical infection if a few bacteria get into the wound; you need to have a small colony enter (hundreds or thousands) to get a foothold.  But, once you cross a threshold, the problem grows fast.&lt;/p&gt;&#xA;" OwnerUserId="12502" LastActivityDate="2018-03-29T04:39:59.490" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13768" PostTypeId="2" ParentId="13755" CreationDate="2018-03-29T05:02:24.373" Score="4" Body="&lt;p&gt;As the continental crust is too buoyant (light) to be subducted, when two continents collide they smash against each other creating a mountain range, in this case the Himalayas.&#xA;This process happen trough &lt;a href=&quot;https://en.wikipedia.org/wiki/Thrust_fault&quot; rel=&quot;nofollow noreferrer&quot;&gt;thrusting&lt;/a&gt; and folding of the plates, leading to something called lithospheric shortening. Which basically means that the plates (&lt;a href=&quot;https://en.wikipedia.org/wiki/Lithosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;lithosphere&lt;/a&gt; is the stuff of which plates are made of) gets shorter. In other words: &lt;strong&gt;the area of the colliding continents gets smaller&lt;/strong&gt;. And the missing area is used to build up the mountains by thrusting and folding, a process that is nicely illustrated by the following animated GIF that I put together from &lt;a href=&quot;http://emvc.geol.ucsb.edu/2_infopgs/IP5TransR/fPlioPleistShortening.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;a video&lt;/a&gt; by the &lt;a href=&quot;http://emvc.geol.ucsb.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Department of Earth Sciences&lt;/a&gt; of &lt;a href=&quot;https://www.ucsb.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;UC Santa Barbara&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lCQQT.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lCQQT.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13558/volcanoes-in-the-alps-and-himalayas-and-the-subduction-of-tethys-sea/13572#13572&quot;&gt;this question&lt;/a&gt;, this process is also discussed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In regard  of the Monsoon, it is not a direct consequence of this collision. But it is due to the fact that Eurasia is a big continent close to the equatorial Indian ocean. Now, as this collision helped to put together Eurasia and bring it closer to the equatorial Indian ocean in the area associated with the Monsoon, you can argue that played a significant role in creating the Monsoons as we know them.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-03-29T05:02:24.373" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13769" PostTypeId="1" CreationDate="2018-03-29T12:44:24.647" Score="4" ViewCount="57" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FH2Zj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FH2Zj.jpg&quot; alt=&quot;Figure 1&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The above image is taken from &quot;Atmosphere–Ocean Momentum Exchange in General Circulation Models&quot;, John A.T.Bye 1999. It represents the inertial coupling concept between the atmosphere and ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is a concept which helps to model momentum transfer between the atmosphere and ocean, taking into account gravity waves on the surface of the ocean. This diagram is used to help illustrate the formulation of shear stress vectors for both the atmosphere and ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only problem I have is I do not know what is meant by reference velocity? Supposedly this velocity is shared between both mediums, atmosphere and ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What could this refer to?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any help at all would be appreciated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;" OwnerUserId="12557" LastActivityDate="2018-03-29T12:44:24.647" Title="What does this reference velocity refer to? (Atmosphere-Ocean Momentum Exchange)" Tags="|atmosphere-modelling|ocean-models|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13772" PostTypeId="2" ParentId="13761" CreationDate="2018-03-29T16:05:05.797" Score="1" Body="&lt;p&gt;For a comprehensive literature review of sources of lightning fatalities data you can check the paper &quot;&lt;a href=&quot;http://lsg.biology.ualberta.ca/facilities/safety/uploads/PDF/Lightning-relatedinjuriesandfatalitiesinCanada_FINAL-TECHNICAL_1-September-06.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Striking Back: An Assessment of Lightning related Fatality and Injury Risk in Canada&lt;/a&gt;&quot;, it covers US and Canadian sources. But if you want to know which one is the largest and arguably the best. That would be &lt;a href=&quot;https://www.ncdc.noaa.gov/stormevents/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA's Storm Database&lt;/a&gt;. The data you can access trough the online interface is quite limited, so I would recommend to go to the &lt;a href=&quot;https://www.ncdc.noaa.gov/stormevents/ftp.jsp&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bulk Data Download&lt;/a&gt; area, and get the original spreadsheets. You will see 3 files per year: Locations, Fatalities and Details, from 1950 to 2017. I would recommend to download the &quot;Details&quot; files, as it also have information about the location (Lat/Lon) and number of deaths and injuries, and a short narrative of the event.&#xA;It is a large table, as an example, I took the following screenshot of the most important data columns for all the lightning events with casualties in 2009:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cYrhS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cYrhS.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can download the Fatalities file if you want more info abut the age, gender and location of the victim. The relevant fields look like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1HSsP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1HSsP.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-03-29T16:05:05.797" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13773" PostTypeId="1" AcceptedAnswerId="13774" CreationDate="2018-03-29T16:44:40.067" Score="4" ViewCount="41" Body="&lt;p&gt;Currently I do some research about SODAR and at &lt;a href=&quot;https://ac.els-cdn.com/S1352231097003853/1-s2.0-S1352231097003853-main.pdf?_tid=982ada2c-a959-4c4d-af9c-1e5de179c7da&amp;amp;acdnat=1522340401_61816cf131c03b50bbfc47eb9ab31617&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt;, the author wrote (p. 1502f):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A site should be relatively clear of obstacles that could act as&#xA;  potential fixed-echo reflectors. If that is not possible, then it is&#xA;  therefore important to construct an &lt;strong&gt;obstacle vista diagram&lt;/strong&gt; prior to&#xA;  sodar installation  which  identifies  the  direction  and  height &#xA;  of potential reflectors in relation to the sodar (Baxter, 1994, 1996).&#xA;  This diagram can be used after some data have been collected to assess&#xA;  whether or not reflections are of concern at some sodar height ranges.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, I can't find any access to the referenced literature and google wasn't helpful either. So, what is an obstacle vista diagram and how to construct it?&lt;/p&gt;&#xA;" OwnerUserId="12558" LastActivityDate="2018-03-29T17:13:44.417" Title="What is an 'obstacle vista diagram'?" Tags="|meteorology|wind|remote-sensing|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13774" PostTypeId="2" ParentId="13773" CreationDate="2018-03-29T17:13:44.417" Score="3" Body="&lt;p&gt;Just taking a guess from the context, I think it could be a &quot;view shed&quot;, the term used in GIS (Geographic Information Systems) to refer to a visibility analysis. In other words, it is a calculation that determines which areas of a given terrain would be visible from a specific point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is used to know, for example, what would be the coverage of a radio transmitter on a given location, or from which areas would a lighthouse not be visible, etc. To calculate such diagram you need a DEM (Digital Elevation Model) of the area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To give you an example I just loaded a DEM and run a calculation (using Global Mapper) of the areas visible from a 20 meters tall tower in the top of a specific hill, and within a 40 km radius. And this is how the results looks like:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/k58LV.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/k58LV.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where the red shading show the areas that are visible from the tower. The rest of the terrain would be hidden behind topographic obstacles.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-03-29T17:13:44.417" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13776" PostTypeId="1" CreationDate="2018-03-30T06:58:58.680" Score="5" ViewCount="190" Body="&lt;p&gt;What characteristics does Porcelain possess that makes it a good choice for the Streak test?&#xA;Additionally, are there any other materials that could also be used for designing a Streak plate?&lt;/p&gt;&#xA;" OwnerUserId="12561" LastActivityDate="2018-03-30T14:23:05.013" Title="What is the motivation behind the choice of unglazed Porcelain as a Streak plate?" Tags="|geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13778" PostTypeId="2" ParentId="13776" CreationDate="2018-03-30T14:23:05.013" Score="5" Body="&lt;ol&gt;&#xA;&lt;li&gt;It's white, so the streak colour is obvious.&lt;/li&gt;&#xA;&lt;li&gt;It's hard. Porcelain is made from aluminosilicates like sillimanite and mullite. Mohs hardness is around 7. Not many geological materials are harder than it, and streak is not a diagnostic feature for those that are harder.&lt;/li&gt;&#xA;&lt;li&gt;It's rough (i.e. unglazed) so it's really good in breaking tiny fragments from the tested material, thus producing the streak.&lt;/li&gt;&#xA;&lt;li&gt;It's cheap and widely available.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-03-30T14:23:05.013" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13780" PostTypeId="2" ParentId="13759" CreationDate="2018-03-30T17:44:19.493" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Areas where the buildings are built on top of a deep layer of loose sediments are widely recognised as being more prone to earthquake damage...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes. To be clear, this is not the same the same thing as saying that loose soils actually &quot;amplify&quot; seismic waves. If anything, both P waves and S waves are attenuated by unconsolidated materials.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, like eSurfsnake mentions, buildings behave poorly when soils shift randomly beneath them: one corner of a tenement may drop several feet and shear off part of the structure injuring scores of people. On the other hand, the structure may be earthquake-proof, but may not have been built on an earthquake-proof foundation, in which case, shaking the loose soil effectively &quot;liquifies&quot; its load-bearing properties.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/malRX.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/malRX.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You tend to find this situation in flat outwash plains like river valleys; places where land is easy to build on, and easy to populate, further &quot;amplifying&quot; an earthquake's effects:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/H9PAt.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/H9PAt.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2018-03-30T17:44:19.493" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13788" PostTypeId="1" CreationDate="2018-03-31T06:51:42.857" Score="1" ViewCount="103" Body="&lt;p&gt;Is there a way to measure the overall feel of the weather for a place?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Suppose that:&lt;br&gt;&#xA;Place A has Temperature $33^o C$, Humidity $57\%$, Wind $14\;km/hr$, and Precipitation $20\%$&lt;br&gt;&#xA;Place B has Temperature $37^o C$, Humidity $11\%$, Wind $14\;km/hr$, and Precipitation $0\%$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which place would feel better?&lt;/p&gt;&#xA;" OwnerUserId="12570" LastEditorUserId="6298" LastEditDate="2018-03-31T11:05:18.640" LastActivityDate="2018-03-31T11:16:43.397" Title="How should one compare the comfort of climates?" Tags="|meteorology|climate|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13790" PostTypeId="2" ParentId="13788" CreationDate="2018-03-31T07:50:03.790" Score="3" Body="&lt;p&gt;One measure that could be used is the &lt;a href=&quot;https://www.ncdc.noaa.gov/societal-impacts/apparent-temp/at&quot; rel=&quot;nofollow noreferrer&quot;&gt;apparent temperature&lt;/a&gt;, which combines air temperature, humidity and wind speed to derive the temperature that the human body feels. It is sometimes referred to as the &quot;feels like&quot; temperature or the Steadman temperature, after Robert Steadman who proposed the idea in 1971. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The formula used by the National Oceanic and Atmospheric Agency, for calculating the apparent temperature is:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt; AT = -2.7 + 1.04*T + 2.0*e -0.65*v&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;where AT and T (air temperature) are °C, e is vapor pressure in kPa,&#xA;and v is 10m wind speed in m/sec. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most weather oraganizations include the calculated apparent temperature in their weather reports.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-03-31T07:50:03.790" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13791" PostTypeId="2" ParentId="13788" CreationDate="2018-03-31T10:57:21.213" Score="2" Body="&lt;p&gt;Indeed, there are some standard measures of &lt;a href=&quot;https://en.wikipedia.org/wiki/Apparent_temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;apparent temperature&lt;/a&gt; which are derived from important things like body heat loss, as well as all sorts of proprietary formulations such as &lt;a href=&quot;http://birmingham.raycomweather.com/2015/06/heat-index-vs-feels-like-temperature.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Feels-Like temperature&lt;/a&gt; that attempt to throw in many extra factors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But in the end, different people do indeed enjoy the feel of different climates, and so it becomes somewhat subjective.  Not sure a large percentage of the population agrees, but I actually much favor the the feel of moist hot weather as opposed to dry hot weather with the same temperature.  And I've known others who will get shivers anytime the temperature drops below 80 °F (26.7 °C).  So when you say &quot;feel better&quot;, indeed any estimate is going to be debatable in its validity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also note, it'd seem hard to incorporate the probability of precipitation into a comfort metric in a meaningful way.  It either rains or it doesn't; a 20% POP day feels the exact same as a 0% POP day, all other conditions being equal, if the rain doesn't occur.  Now obviously getting soaked may not be the cup of tea for everyone... but &lt;a href=&quot;https://youtu.be/w40ushYAaYA?t=60&quot; rel=&quot;nofollow noreferrer&quot;&gt;there are some&lt;/a&gt;!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-03-31T11:16:43.397" LastActivityDate="2018-03-31T11:16:43.397" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13793" PostTypeId="1" CreationDate="2018-04-01T14:20:42.493" Score="4" ViewCount="722" Body="&lt;p&gt;I am looking for a video of global cloud cover. Something like an animated version of this image:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kscc4.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kscc4.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;(Originally presented at &lt;a href=&quot;http://naturalearth.springercarto.com/ne3_data/8192/clouds/africa_clouds_8k.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://naturalearth.springercarto.com/ne3_data/8192/clouds/africa_clouds_8k.jpg&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Any ideas of where to find such video?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks a lot&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bernie &lt;/p&gt;&#xA;" OwnerUserId="12573" LastEditorUserId="11908" LastEditDate="2018-04-01T23:09:18.607" LastActivityDate="2022-06-17T17:40:03.397" Title="Looking for global cloud cover animations or videos" Tags="|meteorology|clouds|weather-satellites|gis|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13794" PostTypeId="1" CreationDate="2018-04-01T15:10:42.010" Score="2" ViewCount="118" Body="&lt;p&gt;This is a follow up question to an earlier question I asked about how groundwater gets mapped. I have read that our groundwater is getting exhausted as people drill to deeper depths and lift prehistoric water, water that got trapped and stored before humans walked the Earth. The same articles also talk about the millions of years it takes to refill those reservoirs, and then extoll about how we need to use less water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is this: What controls how quickly they refill with rainwater? Could these reservoirs be refilled faster if an outside pump refilled them using rainwater? What are the energy economics on doing this for a place like Nebraska or Bangladesh?&lt;/p&gt;&#xA;" OwnerUserId="12545" LastActivityDate="2018-04-02T03:23:30.200" Title="What controls how quickly groundwater gets recharged from rainfall?" Tags="|groundwater|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13795" PostTypeId="2" ParentId="13793" CreationDate="2018-04-01T18:30:06.787" Score="2" Body="&lt;p&gt;That kind of &quot;moving clouds animation&quot; is a very common one, as it is used routinely to aid in weather forecasting. However, it is not very common to see it in a whole-world geographic projection as the example you show, I'll elaborate later on why that's the case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Traditionally, a common source of &quot;cloud animations&quot;, have been NOAA's geostationary &lt;a href=&quot;https://en.wikipedia.org/wiki/Geostationary_Operational_Environmental_Satellite&quot; rel=&quot;nofollow noreferrer&quot;&gt;GOES satellites&lt;/a&gt;, in operation since 1975, with 17 satellites launched so far and more to come.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are looking for visually compelling animations, the latest &lt;a href=&quot;https://en.wikipedia.org/wiki/GOES-16&quot; rel=&quot;nofollow noreferrer&quot;&gt;GOES-16&lt;/a&gt; satellite is capable of producing color images of the Earth's disk every 15 minutes at a resolution of 0.5 km per pixels (at the equator). They look like this:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/AsFtX.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AsFtX.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And you can access images and animations pretty much right after acquisition, here is an example of the 24 hours before I posted this (reduced to a 20% of the size due to Stack Exchange upload size limits):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OeRCh.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OeRCh.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see updated animations at any time on the &lt;a href=&quot;https://www.star.nesdis.noaa.gov/GOES/GOES16_FullDisk_Band.php?band=GEOCOLOR&amp;amp;length=96&quot; rel=&quot;nofollow noreferrer&quot;&gt;GOES-East Image viewer&lt;/a&gt;.&#xA;More traditional, B&amp;amp;W images (infrared band) can be found in the &lt;a href=&quot;http://www.goes.noaa.gov/goesfull.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA GOES page&lt;/a&gt;, or many other weather data sources. Also, beside GOES satellites there are many other geostationary weather satellites that cover different parts of the globe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason images like the one you posted are rare (whole-Earth images), is because these kind of images are either taken from:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Geostationary_orbit&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geostationary orbits&lt;/a&gt;, that can't see polar areas and suffer of a strong degradation of the ground resolution per pixel at higher latitudes, or&lt;/li&gt;&#xA;&lt;li&gt;Polar sun-synchronous orbits, like &lt;a href=&quot;https://en.wikipedia.org/wiki/Moderate-resolution_imaging_spectroradiometer&quot; rel=&quot;nofollow noreferrer&quot;&gt;MODIS&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Suomi_NPP&quot; rel=&quot;nofollow noreferrer&quot;&gt;Suomi&lt;/a&gt;, that allow whole-world composites but using images from multiple passes. Therefore, the full image is composed of images acquired at different times, leading to an ambiguity in the image's time and an impossibility to produce a seamless image, due to the de displacements of the clouds between the different passes.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://worldview.earthdata.nasa.gov/?p=geographic&amp;amp;l=VIIRS_SNPP_CorrectedReflectance_TrueColor,MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor(hidden),Reference_Labels(hidden),Reference_Features(hidden),Coastlines&amp;amp;t=2018-03-31&amp;amp;z=3&amp;amp;v=-337.1739851286173,-133.88359123794208,202.8260148713827,128.52265876205792&quot; rel=&quot;nofollow noreferrer&quot;&gt;Worldview&lt;/a&gt; is a great source of such multi-temporal composites, and as an example, here is a preview of yesterday's cloud cover by Suomi:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/qP24Y.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qP24Y.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://worldview.earthdata.nasa.gov/?p=geographic&amp;amp;l=VIIRS_SNPP_CorrectedReflectance_TrueColor,MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor(hidden),Reference_Labels(hidden),Reference_Features(hidden),Coastlines&amp;amp;t=2018-03-31&amp;amp;z=3&amp;amp;v=-337.1739851286173,-133.88359123794208,202.8260148713827,128.52265876205792&quot; rel=&quot;nofollow noreferrer&quot;&gt;Worldview&lt;/a&gt; also allows to produce animations of the cloud cover spanning several months at one day interval. You just have to click on the video icon in the lower left and select the dates interval.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.star.nesdis.noaa.gov/GOES/GOES16_FullDisk_Band.php?band=GEOCOLOR&amp;amp;length=96&quot; rel=&quot;nofollow noreferrer&quot;&gt;GOES-East Image viewer&lt;/a&gt; stores images of the last four days (with some gaps some times), if you bulk-download them you can create longer animations. As an example, I just did a one of the last four days that you can see &lt;a href=&quot;https://youtu.be/mLyel99E2mY&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; (I do recommend to enable HD resolution).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another interesting one, that also allow for animated display is the &lt;a href=&quot;https://epic.gsfc.nasa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;EPIC camera on DSCOVR satellite&lt;/a&gt;. Despite that the time resolution is a bit too low for looking at the clouds evolution, its unique perspective from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Lagrangian_point&quot; rel=&quot;nofollow noreferrer&quot;&gt;L1 point&lt;/a&gt; (42 times further than geostationary orbits) allow a full view of the illuminated side of the Earth. In addition from the animation in the link above, &lt;a href=&quot;https://www.youtube.com/watch?time_continue=22&amp;amp;v=CFrP6QfbC2g&quot; rel=&quot;nofollow noreferrer&quot;&gt;this video is also worth checking&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can also find animations created using models instead of real data. That approach allows seamless global coverage at an arbitrarily high temporal resolution. A nice example is the &lt;a href=&quot;https://www.youtube.com/watch?v=qh011eAYjAA&quot; rel=&quot;nofollow noreferrer&quot;&gt;one year long animation (at one hour time steps) of cloud cover and precipitation&lt;/a&gt; created from the &lt;a href=&quot;http://www.cesm.ucar.edu/models/ccsm4.0/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCAR's CESM model&lt;/a&gt;.  &lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-04-03T15:37:49.810" LastActivityDate="2018-04-03T15:37:49.810" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13796" PostTypeId="2" ParentId="8523" CreationDate="2018-04-01T18:32:22.053" Score="2" Body="&lt;p&gt;When a bus or truck goes by, you typically hear it before you feel it, so you already know what it is &lt;em&gt;before&lt;/em&gt; any noticeable ground motion starts, and your brain accepts the shaking as being due to the vehicle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In an earthquake, on the other hand, unless it's strong enough to actually start noticeably moving objects around (and I'm assuming that, when you specify a &lt;em&gt;mild&lt;/em&gt; earthquake, you mean one that &lt;em&gt;isn't&lt;/em&gt; strong enough to do that), your brain has no advance warning - suddenly, the vestibular system is reporting motion, while the eyes are reporting that you're stationary.  Your brain can interpret this one of two ways:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The ground is shaking, and the building, and, therefore, you, with it.&lt;/li&gt;&#xA;&lt;li&gt;The vestibular system is malfunctioning.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;As temporary glitches in the vestibular system (i.e., dizziness) are (hopefully) a more common experience for most people than (even mild) earthquakes, your brain assumes that the culprit is the vestibular system, rather than the ground, and you feel dizzy until you realise that it's actually an earthquake.&lt;/p&gt;&#xA;" OwnerUserId="12549" LastActivityDate="2018-04-01T18:32:22.053" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13797" PostTypeId="2" ParentId="8523" CreationDate="2018-04-02T01:20:52.117" Score="0" Body="&lt;p&gt;I live in Southern California (Inland Empire, near the San Andreas and San Jacinto faults). I did not grow up here. I don't think I've ever mistaken an earthquake for dizziness. During mild ones that have a short 'signature' (a jolt) and that occur while I'm at work, I often wonder first whether someone dropped something on a floor above me. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the few stronger ones that last longer, I pretty quickly realize it's an earthquake--maybe because I don't often have dizzy spells and don't drink alcohol.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've missed some of the biggest ones as Northridge (1994) happened a few months before I moved to California. &lt;/p&gt;&#xA;" OwnerUserId="1339" LastActivityDate="2018-04-02T01:20:52.117" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13798" PostTypeId="2" ParentId="13794" CreationDate="2018-04-02T03:23:30.200" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;What controls how quickly they refill with rainwater?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Really it depends on where the aquifer is. Letting rain top off a Hawaiian aquifer may take a few weeks. However, refilling the aquifer beneath the Atacama desert may take tens of millions of years. That assumes that the recharge source is actually overlying the aquifer; in many cases, it's not, thus adding lateral distance that recharge must travel.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regardless, drawing down an aquifer does lasting damage and they will never refill to the same reservoir capacity. Once groundwater is pumped out, the solid materials are then free to further compact and reduce the pore spaces that would be re-filled. In the case of California's San Joaquin Valley this sediment compaction, or, surface subsidence, has caused a permanent loss of nearly %10 of the aquifer's recharge volume.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Could these reservoirs be refilled faster if an outside pump refilled&#xA;  them using rainwater?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In one sense, sure, there are groundwater recharge systems that work as closed-loop systems: groundwater is pulled out of the ground for use by a community, treated by the waste-water system after being used, then pumped back underground some distance upgradient. Aurora, Colorado, for one, has such a system in place. Note that the system isn't used to filter the used groundwater, but to keep it from being wasted when draining it to a local river. Furthermore, groundwater levels must be kept stable lest compaction ruin reservoir capacity.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What are the energy economics on doing this for a place like Nebraska&#xA;  or Bangladesh?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They may be entirely manageable, but the politics would be NUTS! After all, rainwater is a &quot;surface&quot; resource that is promised to users downstream from where it falls. Diverting it underground for the exclusive use of a community would be like trucking parts of Himalayan glaciers to Delhi with no regard to downstream users who depend, for example, on the Ganges.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could fill a couple of academic libraries with proper answers to your questions, by the way!&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2018-04-02T03:23:30.200" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13800" PostTypeId="1" CreationDate="2018-04-02T09:21:13.013" Score="5" ViewCount="197" Body="&lt;p&gt;For example if I use a public transport which is burning fuel with or without my presence, how one could calculate carbon footprint?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope I am in the  right place for asking this question.&lt;/p&gt;&#xA;" OwnerUserId="12577" LastActivityDate="2018-04-03T09:41:41.960" Title="If a person uses public transport, how much carbon is added to the footprint?" Tags="|carbon|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13806" PostTypeId="1" AcceptedAnswerId="13807" CreationDate="2018-04-02T20:38:02.290" Score="4" ViewCount="121" Body="&lt;p&gt;I'm programming the nonlinear Stokes problem (with a finite element method),&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\operatorname{div}(\mu(u)\nabla u+pI)=f$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $\mu(u)$ is the Glen's power flow law (typical for glaciers). I want to test the model with &lt;strong&gt;simple&lt;/strong&gt; and &lt;strong&gt;realistic&lt;/strong&gt; data. Do you know where can I find simple tests and realistic examples (e.g. a mesh of a glacier and the physical constants)?&lt;/p&gt;&#xA;" OwnerUserId="12582" LastEditorUserId="28050" LastEditDate="2018-04-03T00:37:37.467" LastActivityDate="2018-04-03T00:37:37.467" Title="Simple and realistic data for glacier modeling" Tags="|glaciology|numerical-modelling|glacier|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13807" PostTypeId="2" ParentId="13806" CreationDate="2018-04-02T20:59:47.347" Score="3" Body="&lt;p&gt;Testing and model inter-comparison have been an important part of glacier models developments. One of the main numerical modelling suites used by the glaciology community is &lt;a href=&quot;http://elmerice.elmerfem.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Elmer Ice&lt;/a&gt;, a full-Stokes, finite element, ice sheet/ice flow model. As part of the effort to test models the community around Elmer Ice developed &lt;strong&gt;ISMIP-HOM&lt;/strong&gt; (Ice Sheet Model Intercomparison Project-Higher-Order ice-sheet Model). ISMIP-HOM consists of five diagnostic and one prognostic experiments, for both 2-D and 3-D geometries. For all the tests, the full-Stokes equations are solved. One of the experiments has an analytical solution obtained from perturbation analysis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The details of each experiment, including input data can be found at the ISMIP-HOM project page maintained by Frank Pattyn at: &lt;a href=&quot;http://homepages.ulb.ac.be/~fpattyn/ismip/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://homepages.ulb.ac.be/~fpattyn/ismip/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some papers that I would recommend looking at to find out more details about the experiments are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.the-cryosphere.net/2/95/2008/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Benchmark experiments for higher-order and full-Stokes ice sheet models (ISMIP–HOM)&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.the-cryosphere.net/2/67/2008/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The ISMIP-HOM benchmark experiments performed using the Finite-Element code Elmer&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.the-cryosphere.net/6/573/2012/tc-6-573-2012.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Results of the Marine Ice Sheet Model Intercomparison Project, MISMIP&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-04-02T20:59:47.347" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13808" PostTypeId="1" AcceptedAnswerId="13810" CreationDate="2018-04-02T21:18:10.167" Score="5" ViewCount="195" Body="&lt;p&gt;What is the difference between &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\operatorname{div}(-\mu(u)\nabla u+pI)=f\tag{1}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\operatorname{div}(-\mu(u)(\nabla u\color{red}{+(\nabla u)^\mathsf{T}})+pI)=f\tag{2}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;from the physical point of view, in the glacier modeling context?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Does it make sense to model a glacier with the first one?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To explain the notation, $u$ and $p$ denote the velocity and pressure fields, respectively; $\mu(u)$ denotes a velocity-dependent viscosity coefficient (for example, Glen's power flow law). The gradient of $u$ is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\nabla u=\left(\begin{array}{cc}\dfrac{\partial u_1}{\partial x}&amp;amp;\dfrac{\partial u_1}{\partial y}\\ \dfrac{\partial u_2}{\partial x}&amp;amp;\dfrac{\partial u_2}{\partial y}\end{array}\right)$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and $(\nabla u)^\mathsf{T}$ denotes the transpose matrix of $\nabla u$. (If $u$ has 3 variables its gradient is analogous to the 2-variable case). Frequently, $f$ is $f=(0,0,-\rho g)$, where $g$ is the gravitational acceleration constant and $\rho$ the ice density. $I$ denotes the identity matrix and $div$ the divergence of a matrix is the divergence by rows, for example,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\operatorname{div}\left(\begin{array}{cc}w_1&amp;amp;w_2\\ s_1&amp;amp; s_2\end{array}\right)=\left(\begin{array}{cc}\dfrac{\partial w_1}{\partial x}+\dfrac{\partial w_2}{\partial y}\\ \dfrac{\partial s_1}{\partial x}+\dfrac{\partial s_2}{\partial y}\end{array}\right).$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This way, we may rewrote (1) and (2), respectively, as follows:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$-\operatorname{div}(\mu(u)\nabla u)+\nabla p=f$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$-\operatorname{div}(\mu(u)(\nabla u\color{red}{+(\nabla u)^\mathsf{T}})+\nabla p=f$$&lt;/p&gt;&#xA;" OwnerUserId="12582" LastEditorUserId="28050" LastEditDate="2018-04-03T00:35:29.327" LastActivityDate="2018-04-03T00:35:29.327" Title="Nonlinear Stokes equations for glacier modeling" Tags="|models|glaciology|glacier|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13810" PostTypeId="2" ParentId="13808" CreationDate="2018-04-02T22:33:28.690" Score="4" Body="&lt;p&gt;If your viscosity $\mu(u)$ is constant, then there is no difference between the two formulations because &#xA;$$&#xA;  \text{div} (\mu \nabla u^t) = \mu \nabla (\text{div} u)&#xA;$$&#xA;and for incompressible materials $\text{div} u=0$. So the two formulations are identical for constant viscosities. For variable viscosities, this is a bit more complicated and may in fact not be correct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, the second form you show (with the addition of the transpose of the gradient) is the physically correct form because it involves the strain rate $\varepsilon  = \frac 12(\nabla u + \nabla u^t)$ which is the physically correct quantity where the gradient $\nabla u$ has no physical reality. (This is because the invariants of $\varepsilon$ are independent of the choice of coordinate system, but the invariants of $\nabla u$ depend on the choice of coordinate system.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first form you show is a simplification one can work with if you know that (i) you have an incompressible fluid, and (ii) you have no Neumann type boundary conditions (as the &quot;natural&quot; boundary conditions for the two formulations are different).&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2018-04-02T22:33:28.690" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13811" PostTypeId="2" ParentId="13800" CreationDate="2018-04-03T07:01:35.973" Score="3" Body="&lt;p&gt;I'm no expert on such subjects, but did &lt;a href=&quot;https://www.google.com/search?q=carbon%20footprint%20by%20transportation%20type&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google&lt;/a&gt; and immediately this &lt;a href=&quot;https://www.theguardian.com/environment/datablog/2009/sep/02/carbon-emissions-per-transport-type&quot; rel=&quot;nofollow noreferrer&quot;&gt;Guardian article&lt;/a&gt; offering a &lt;a href=&quot;https://docs.google.com/spreadsheets/d/1TAMZLvUrMlxAR4RdDOs928-yoU5RxMrDKIb8tXuOKsc/edit?hl=en_GB&amp;amp;hl=en_GB#gid=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;dataset&lt;/a&gt; apparently attributed to Camden Council/travelfootprint.org/Clear Zone Partnership.  There are a lot of different values, but (if I understand the columns labels correctly), a rough breakdown of the footprints would be ranges of:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bus: 20-90 g CO$_2$/km&lt;br&gt;&#xA;Train, Diesel/Diesel-Electric: 30-150 g CO$_2$/km&lt;br&gt;&#xA;Train, Electric [Long-Distance or Subway]: 10-70 g CO$_2$/km&lt;br&gt;&#xA;Flight: 190-460 g CO$_2$/km  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Walking: 5-25 g CO$_2$/km&lt;br&gt;&#xA;Biking: 7-18 g CO$_2$/km  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basic car, Diesel: 40-180 g CO$_2$/km&lt;br&gt;&#xA;Basic car, Gasoline: 40-200 g CO$_2$/km&lt;br&gt;&#xA;Basic car, Liquefied Petroleum: 30-180 g CO$_2$/km&lt;br&gt;&#xA;Basic car, Natural Gas: 30-150 g CO$_2$/km&lt;br&gt;&#xA;Basic car, Gasoline Hybrid: 30-150 g CO$_2$/km&lt;br&gt;&#xA;Basic car, Electric: 7-110 g CO$_2$/km&lt;br&gt;&#xA;Motorcycle: 20-190 g CO$_2$/km&lt;br&gt;&#xA;Scooter, Electric: 4-30 g CO$_2$/km  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;[See the report for other automobiles, including family cars, SUV, and minis]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;&lt;sub&gt;(The best end of the range is the more efficient models run at peak capacity in best conditions [rural roads/medium distance short-haul flights]&lt;br&gt;&#xA;The worst end of the range is less-efficient models at quite low capacity in less-efficient conditions [urban roads/very short or long-haul flights]&lt;br&gt;&#xA;[Rail appears fairly similar in all usage circumstances, thus only depending on model/network setup, at least in this UK data])&lt;/sub&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This data attempts to take into account secondary sources (such as power plants for electric vehicles or needs of the agriculture which is used for the energy to walk/bike).  As you can see there's a wide range depending on how most transport is used.  You're best suited diving further into the table to find the most applicable use case for you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My list only shows CO$_2$... the database also includes NO$_2$ and some others pollutants (if you can break down the abbreviations!) which can be very important too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And this is UK-specific.  So the equipment models used, network efficiency, and even climatological conditions will vary for other locations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The date on the article also suggests its almost a decade old.  So we have likely seen some additional improvements in some formats (though it seems unlikely that they are giant leaps in most cases).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hopefully someone will come along with more recent and wide-ranging data, but this seems like a good start at some rough estimates.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-04-03T09:41:41.960" LastActivityDate="2018-04-03T09:41:41.960" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13812" PostTypeId="1" AcceptedAnswerId="13817" CreationDate="2018-04-03T07:19:32.070" Score="9" ViewCount="1082" Body="&lt;p&gt;We know that sea level is rising, though some people say climate change is fake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Altitude&lt;/strong&gt; is defined as the height of something measured from sea level. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since sea level is increasing, and the heights of most things is not: &lt;strong&gt;is the altitude of most things decreasing?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="11519" LastEditorUserId="11908" LastEditDate="2019-03-11T20:58:34.143" LastActivityDate="2019-03-11T20:58:34.143" Title="Is altitude of everything decreasing due to sea level rise?" Tags="|geology|geophysics|climate-change|sea-level|isostasy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13813" PostTypeId="2" ParentId="12387" CreationDate="2018-04-03T10:39:30.683" Score="8" Body="&lt;p&gt;Here is how I would do this. &lt;a href=&quot;https://confluence.ecmwf.int/display/ECC&quot; rel=&quot;nofollow noreferrer&quot;&gt;ECMWF's ECCODES&lt;/a&gt; has a tool called &lt;a href=&quot;https://software.ecmwf.int/wiki/display/ECC/bufr_ls&quot; rel=&quot;nofollow noreferrer&quot;&gt;bufr_ls&lt;/a&gt; and you can use that to  write the contents of that output to a text file. Then I would read that file into a scripting language such as Python and write out the contents as a GRIB file using &lt;a href=&quot;https://pypi.python.org/pypi/pygrib&quot; rel=&quot;nofollow noreferrer&quot;&gt;PyGrib&lt;/a&gt;. You can also explore the output of &lt;a href=&quot;https://software.ecmwf.int/wiki/display/ECC/bufr_dump&quot; rel=&quot;nofollow noreferrer&quot;&gt;bufr_dump&lt;/a&gt; and convert that also to GRIB if you wish. The full list of all BUFR format tools from ecCodes is given in this link &lt;a href=&quot;https://software.ecmwf.int/wiki/display/ECC/BUFR+tools&quot; rel=&quot;nofollow noreferrer&quot;&gt;BUFR tools&lt;/a&gt;&#xA;For more information regarding either of those softwares you can reach out to their support network and then get your doubts resolved. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want a 100 % Pythonic solution then you can try  &lt;a href=&quot;https://github.com/pytroll/python-bufr&quot; rel=&quot;nofollow noreferrer&quot;&gt;Python-Bufr&lt;/a&gt; which basically wraps ECMWF BUFR or use this python BUFR library - &lt;a href=&quot;http://bufrpy.readthedocs.io/en/latest/&quot; rel=&quot;nofollow noreferrer&quot;&gt;bufrpy&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2018-12-17T14:37:57.180" LastActivityDate="2018-12-17T14:37:57.180" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="13814" PostTypeId="5" CreationDate="2018-04-03T11:43:50.250" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2018-04-03T11:43:50.250" LastActivityDate="2018-04-03T11:43:50.250" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13815" PostTypeId="4" CreationDate="2018-04-03T11:43:50.250" Score="0" Body="Questions and answers related to BUFR, Binary Universal Form for the Representation of Meteorological data, which is a binary code designed to represent any meteorological data" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2018-04-03T13:44:12.343" LastActivityDate="2018-04-03T13:44:12.343" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13816" PostTypeId="1" CreationDate="2018-04-03T12:38:13.263" Score="5" ViewCount="99" Body="&lt;p&gt;Why are the Kopet Dag Mountains (on the border between Iran and Turkmenistan) coloured much like the Bulgarian flag?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/zHHbv.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[&lt;a href=&quot;http://www.google.com/maps/place/37%C2%B032&amp;#39;56.1%22N+59%C2%B002&amp;#39;00.3%22E/@37.5489072,59.0159135,6061m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d37.548903!4d59.033423&quot; rel=&quot;nofollow noreferrer&quot;&gt;Link to satellite imagery in Google Maps&lt;/a&gt;]&lt;br&gt;&#xA;(Location is 37.548903 North, 59.033423 East)&lt;/p&gt;&#xA;" OwnerUserId="12586" LastEditorUserId="6298" LastEditDate="2018-04-03T16:03:57.147" LastActivityDate="2018-04-03T16:03:57.147" Title="The coloration of the Kopet Dag Mountains" Tags="|mountains|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13817" PostTypeId="2" ParentId="13812" CreationDate="2018-04-04T04:50:32.813" Score="6" Body="&lt;p&gt;Altitudes are referred to a &lt;a href=&quot;https://en.wikipedia.org/wiki/Geoid&quot; rel=&quot;nofollow noreferrer&quot;&gt;geoid&lt;/a&gt; (an imaginary surface of equal gravity strength), that is chosen to fit the mean sea level. Therefore, if we were to constantly adjust the geoid to fit the rising sea level, all the altitudes would indeed be decreasing &lt;strong&gt;in average&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it is very important to highlight that &lt;strong&gt;&quot;in average&quot;&lt;/strong&gt; part, because of the rates involved. Let's have a look at the sea level rise rates:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/C4rlg.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/C4rlg.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see in the above image (taken from &lt;a href=&quot;http://climateadaptation.hawaii.gov/sea-level-rise/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hawaiʻi Climate Adaptation Portal&lt;/a&gt;), the rates of rise are in the order of 4 mm/yr, a value that is small in comparison with other processes that can also change elevations. When you go down to the millimeter-scale, the topography is much more dynamic than you would think, for example:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Post-glacial_rebound&quot; rel=&quot;nofollow noreferrer&quot;&gt;Post-glacial isostatic rebound&lt;/a&gt;&lt;/strong&gt;: One of the reason the sea level is rising is because the glacier are melting. Mostly from mountain areas. As the glaciers melt, they unload the crust that can be pictured as floating on the mantle (a.k.a. magma at the interior of the Earth), and as any floating object that loose weight, it gain flotation and rises. Typical rates are &lt;a href=&quot;https://en.wikipedia.org/wiki/Post-glacial_rebound#Overview&quot; rel=&quot;nofollow noreferrer&quot;&gt;about 10 mm/yr&lt;/a&gt;, but rates up to &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0012821X09006207&quot; rel=&quot;nofollow noreferrer&quot;&gt;39 mm/yr have been measured&lt;/a&gt; in heavily glaciated areas. Therefore, most mountains in medium and high latitudes are rising faster than the sea level.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Erosion&lt;/strong&gt;: Erosion rates are also of the order milimeters per year &lt;a href=&quot;https://en.wikipedia.org/wiki/Erosion&quot; rel=&quot;nofollow noreferrer&quot;&gt;up to meters per year&lt;/a&gt; in river beds and other areas. So, in some areas the erosion can play a much bigger role than sea level when it comes to elevation change. To make it more complex, erosion will also trigger isostatic rebounding, in many case both processes are in balance at large scales.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Deposition&lt;/strong&gt;: Landforms like stuaries, beaches and deltas, are product of the balance between sediment deposition and erosion. If the sea level rise, the delta will rise too given enough time. The problem currently in some areas, is that the sedimentation can't quite catch up with sea level rise and coastal erosion.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Tectonic_uplift&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tectonic uplift&lt;/a&gt;&lt;/strong&gt;: Tectonics also is constantly changing the elevation trough slow deformation and Earthquakes. Parts of the Himalaya are rising at &lt;a href=&quot;https://en.wikipedia.org/wiki/Geology_of_the_Himalaya&quot; rel=&quot;nofollow noreferrer&quot;&gt;rates of 10 mm/yr&lt;/a&gt;, and large earthquakes can produce sudden elevation changes in the order of &lt;a href=&quot;https://geology.com/records/largest-earthquake/&quot; rel=&quot;nofollow noreferrer&quot;&gt;a few meters&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Tectonic relaxation&lt;/strong&gt;: As volcanic islands cool down, they sink, Hawai'i is doing so at rates of about &lt;a href=&quot;https://www.researchgate.net/publication/228469903_Sea_level_rise_at_Honolulu_and_Hilo_Hawaii_GPS_estimates_of_differential_land_motion&quot; rel=&quot;nofollow noreferrer&quot;&gt;one millimetre per year&lt;/a&gt;. And geologically young volcanoes are sinking due to the extra weight its formation put on the underlying crust.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Therefore, to say that the elevation of something specific is changing &lt;strong&gt;because&lt;/strong&gt; of sea level rise is not something easy to backup, as there are many other processes to take into account. Scientist make fairly complex models to figure out which areas will actually experience flooding due to sea level rise, and unfortunately, so far they have found that there are many highly populated areas that will face big challenges for that reason.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-04-04T22:29:38.467" LastActivityDate="2018-04-04T22:29:38.467" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13818" PostTypeId="1" AcceptedAnswerId="13820" CreationDate="2018-04-04T18:50:23.470" Score="2" ViewCount="725" Body="&lt;p&gt;I have a basic question concerning AVO, AVA, and reflections. What is the difference between AVO/AVA and obliquity factors from a given reflection from a point in the subsurface? If there is a technical difference, how is it accounted for during processing and amplitude conditioning?&lt;/p&gt;&#xA;" OwnerUserId="8447" LastEditorUserId="28050" LastEditDate="2018-04-05T00:32:04.710" LastActivityDate="2018-04-05T11:09:50.493" Title="Seismic AVO/AVA concepts" Tags="|seismic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13819" PostTypeId="1" CreationDate="2018-04-04T20:35:26.470" Score="1" ViewCount="578" Body="&lt;p&gt;Given that monsoon climate has the primary feature of seasonal reversal of wind systems and the same happens in case of Mediterranean climate too, does that mean Mediterranean climate is a special case of Monsoon?&lt;/p&gt;&#xA;" OwnerUserId="12597" LastActivityDate="2018-04-04T20:35:26.470" Title="Is mediterranean climate a type of monsoon climate" Tags="|geography|climatology|monsoon|mediterranean|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13820" PostTypeId="2" ParentId="13818" CreationDate="2018-04-05T00:50:56.963" Score="1" Body="&lt;p&gt;&lt;strong&gt;While the terms are rarely used rigorously, AVO and AVA refer to slightly different versions of the same type of analysis.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The amplitude (and phase) of a seismic reflection varies with the offset &lt;strong&gt;distance&lt;/strong&gt; between the source and receiver. Hence 'amplitude variation with offset', or AVO.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Strictly speaking, however, the variation &amp;mdash; which is given by the &lt;a href=&quot;http://www.subsurfwiki.org/wiki/Zoeppritz_equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zoeppritz equations&lt;/a&gt; &amp;mdash; is with the incidence or offset &lt;strong&gt;angle&lt;/strong&gt;, often called $\theta$. That is, the reflectivity is a function of angle, not of distance. So 'amplitude variation with angle' (AVA) is arguably a better name for the phenomenon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It turns out that the reflectivity varies linearly with respect to $\sin^2\theta$, so we often use that relationship instead, e.g. via &lt;a href=&quot;http://www.subsurfwiki.org/wiki/Shuey_equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;the 2-term Shuey approximation&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$R(\theta) = R(0) + G\sin^2\theta$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where R is the reflectivity and $G$ is a function of P-wave velocity $V_\mathrm{P}$, S-wave velocity $V_\mathrm{S}$, and density $\rho$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we're being strict about the language, the practical difference in seismic analysis is that you'd perform AVO analysis on offset gathers or partial offset stacks (such as you might get directly from processing), and AVA analysis on angle gathers or partial angle stacks (which would require you to interpolate the offset-based data using a velocity model and ray-tracing).&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2018-04-05T11:09:50.493" LastActivityDate="2018-04-05T11:09:50.493" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13821" PostTypeId="1" AcceptedAnswerId="13827" CreationDate="2018-04-05T00:53:06.157" Score="5" ViewCount="1698" Body="&lt;p&gt;Aside from cultural implications (correct me if I'm wrong but artificial diamonds are not so hard to obtain, right?) diamonds are pure carbon and are more unstable than graphite. So, why not use diamonds as fuel?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My approach: steel melts at 1500°C at least (and there are better steel that melt at higher temperatures). It is pretty high compared with diamond combustion temperature that is just 800°C and once you get to that point combustion will generate enough energy to burn diamond itself. So you can burn it in a steel piston.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ok, I admit 800°C is pretty high compared with paper and wood (233–400°C) but it is a clean combustion (you obtain only CO&lt;sub&gt;2&lt;/sub&gt;, assuming a constant oxygen input). From this point of view hydrogen is the only competitor but it rise to 500°C, that is not little.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, what is the practical limitation in the use of diamonds as fossil fuel?&lt;/p&gt;&#xA;" OwnerUserId="11388" LastEditorUserId="28050" LastEditDate="2018-04-05T11:07:37.463" LastActivityDate="2022-02-27T09:15:35.093" Title="Can I use diamonds as fossil fuel?" Tags="|atmospheric-chemistry|economic-geology|carbon|fossil-fuel|diamond|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13822" PostTypeId="2" ParentId="13821" CreationDate="2018-04-05T01:29:33.090" Score="1" Body="&lt;p&gt;Scarcity is the biggest limit, diamonds burn much like coal but unlike coal they are extremely rare. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;artificial diamonds would still cost vastly more to make than digging up coal. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2018-04-05T01:29:33.090" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13825" PostTypeId="1" AcceptedAnswerId="13826" CreationDate="2018-04-05T10:36:03.547" Score="1" ViewCount="563" Body="&lt;p&gt;(I'm not a geologist, just helping my kids collect rocks).&lt;/p&gt;&#xA;" OwnerUserId="12599" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T11:52:53.897" LastActivityDate="2019-08-29T11:52:53.897" Title="How can I tell the difference between granite and syenite?" Tags="|geology|rocks|petrology|igneous|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13826" PostTypeId="2" ParentId="13825" CreationDate="2018-04-05T10:47:05.907" Score="4" Body="&lt;p&gt;It is confusing - both rocks are commonly pink overall. But, granite has abundant quartz, syenite has no quartz to very little. Quartz will be the grey translucent mineral that looks just like a blob with no distinct shape.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can use this website: &lt;a href=&quot;https://www.virtualmicroscope.org&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.virtualmicroscope.org&lt;/a&gt; to see examples of syenite and granite (use the search box).&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-04-05T10:47:05.907" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13827" PostTypeId="2" ParentId="13821" CreationDate="2018-04-05T11:04:20.603" Score="12" Body="&lt;ol&gt;&#xA;&lt;li&gt;Diamonds are expensive. Really expensive. Even &amp;quot;cheap&amp;quot; synthetic diamonds are orders of magnitude more expensive than conventional fossil fuel. By using them as fuel, you will increase demand, thus increasing their price even more. And synthetic diamonds have to be made somehow, and you need energy for that.&lt;/li&gt;&#xA;&lt;li&gt;Diamonds burn, but they don't burn well. For example, look at &lt;a href=&quot;https://youtu.be/WWpm6_Y7ASI&quot; rel=&quot;nofollow noreferrer&quot;&gt;this video&lt;/a&gt; of diamonds burning in pure oxygen. The burning sustains for about a minute after the heat source is removed, but then it stops. So then, you need to apply a constant source of heat, and this requires energy. You will probably have to put in more energy than you get from the combustion of diamonds. Kinetically, diamonds just don't burn as well as other things with carbon (like fuel or wood or coal).&lt;/li&gt;&#xA;&lt;li&gt;One of your arguments is that diamonds burn &amp;quot;cleanly&amp;quot; (let's not forget that CO&lt;sub&gt;2&lt;/sub&gt; is a pollutant as well). Burning of natural gas emits only CO&lt;sub&gt;2&lt;/sub&gt; and H&lt;sub&gt;2&lt;/sub&gt;O, so it's a much better alternative when pollution is a consideration.&lt;/li&gt;&#xA;&lt;li&gt;Diamonds are so much more useful for other things. Don't waste diamonds on energy production!&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;edit:&lt;/p&gt;&#xA;&lt;p&gt;Some commenters argued that diamond isn't actually rare, and the prices are artificially inflated. Maybe, but even then it doesn't make any sense. Every year, &lt;a href=&quot;https://en.wikipedia.org/wiki/Diamond#Mining&quot; rel=&quot;nofollow noreferrer&quot;&gt;26 tons of diamond are mined&lt;/a&gt;. Even if there's a conspiracy, and mining companies actually ten times more at 260 tons per year, this amount is  absolutely dwarfed by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Coal#Major_producers&quot; rel=&quot;nofollow noreferrer&quot;&gt;7 billion tons of coal produced annually&lt;/a&gt;. Even if you're burning every single diamond produced, this will be absolutely negligible compared to the amount of coal (and other fossil fuels) currently used as fuels.&lt;/p&gt;&#xA;&lt;p&gt;Don't forget about grade. Coal seams are close to pure carbon. Let's take for example 85% combustible material in a rock. Then you're getting 850 kg of carbon in one ton of rock. Diamond grade is much lower. If you're extremely lucky, you can get about &lt;a href=&quot;https://www.911metallurgist.com/blog/kimberlite-deposits-and-geology-formation-of-diamonds&quot; rel=&quot;nofollow noreferrer&quot;&gt;70 grams of diamond in one ton of rock&lt;/a&gt;. Most often you're getting less than 1 gram per ton of diamond. So unlike coal which can be burnt as mined, diamond has to be separated from its host rock. This adds yet another time consuming and costly process in order to produce diamond raw material which is less suitable for combustion relative to its chemically identical coal.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2022-02-27T09:15:35.093" LastActivityDate="2022-02-27T09:15:35.093" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="13828" PostTypeId="1" AcceptedAnswerId="13836" CreationDate="2018-04-05T12:30:23.203" Score="9" ViewCount="1032" Body="&lt;p&gt;This might seem like a basic question, but I'm a little confused about the effects on ocean acidification of different carbon compounds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have heard that increased levels of carbon dioxide in the atmosphere are causing ocean acidification, lowering the ocean's pH.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have also heard that shellfish like mussels and oysters can be used as a carbon sink, making shellfish farming a form of carbon sequestration. This makes sense, as their shells contain carbon in the form of calcium carbonate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is how does such sequestration affect ocean acidification? On the one hand, sequestering the carbon as calcium carbonate would lower the carbon presence in the ocean, which would seem to reduce the effects of CO&lt;sub&gt;2&lt;/sub&gt;. On the other hand, calcium carbonate is alkali: leaching minerals from the ocean to form such shells would seem to increase acidity (since the opposite process, dissolving calcium carbonate, reduces acidity).&lt;/p&gt;&#xA;" OwnerUserId="12601" LastEditorUserId="6129" LastEditDate="2020-05-05T14:08:38.167" LastActivityDate="2021-09-18T10:08:18.680" Title="Carbon's role in ocean acidification" Tags="|climate-change|oceanography|geochemistry|carbon-cycle|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13829" PostTypeId="1" AcceptedAnswerId="13978" CreationDate="2018-04-05T15:03:01.760" Score="6" ViewCount="455" Body="&lt;p&gt;In Dr Hua-Wei Zhou's book &lt;em&gt;Practical Seismic Data Analysis&lt;/em&gt; (2014), he includes and explains figures from previous classic works (i.e. Schneider, 1971) in order to describe migration from a fundamental level. On pages 212–213, the following figures (and questions) are shown below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AKTGy.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AKTGy.png&quot; alt=&quot;Figure 13 from book&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NdQXa.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NdQXa.png&quot; alt=&quot;Figure 14 from book&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Question 1&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;For &lt;strong&gt;Figure 14&lt;/strong&gt;, he says that &quot;in the case of a constant velocity model, the equal-traveltime contour will be a &lt;strong&gt;hyperbolic&lt;/strong&gt; surface centered over the image point&quot; - my question is this: &lt;em&gt;why&lt;/em&gt; is it a hyperbola and not a semi-circle? In John Claerbot's &lt;em&gt;Imaging the Earth's Interior&lt;/em&gt;, he claims that the equation of a wave front a given constant time results in a semi-circle and not a hyperbola.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Question 2&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;In &lt;strong&gt;Figure 13&lt;/strong&gt;, he also says that &quot;in the case of a constant velocity model, the equal traveltime contour will be an &lt;strong&gt;elliptical&lt;/strong&gt; surface with the source and receiver as the two foci&quot; - again, my question is this: why is this an elliptical surface in this particular scenario? Why not a semi-circle?&lt;/p&gt;&#xA;" OwnerUserId="8447" LastEditorUserId="28050" LastEditDate="2018-04-25T14:29:43.037" LastActivityDate="2018-04-25T14:29:43.037" Title="Seismic migration concepts" Tags="|geophysics|models|seismic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13830" PostTypeId="1" CreationDate="2018-04-05T20:50:34.623" Score="6" ViewCount="139" Body="&lt;p&gt;I am trying to find a way to describe the relative soil fertility   characteristics for the islands of Hawaii, Maui, and Kauai (youngest&lt;br&gt;&#xA;to oldest).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to know about their nitrogen fixation, soil leaching, and limiting nutrients for each island. How can I find this information?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you   &lt;/p&gt;&#xA;" OwnerUserId="12218" LastActivityDate="2019-01-07T05:43:13.800" Title="How does one find the soil fertility characteristics for islands of Hawaii?" Tags="|soil|nitrogen|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13831" PostTypeId="1" CreationDate="2018-04-06T17:22:07.417" Score="13" ViewCount="498" Body="&lt;p&gt;I understand that clouds can be made out of water droplets and/or ice crystals. And that fog is nothing else than low-lying clouds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I've experienced fog in a wide ranges of temperatures. I like mountaineering and you often get fog high in the mountains. I've been lucky enough to visit the high mountains of Antarctica and I've also experienced fog there at very low temperatures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This &lt;a href=&quot;https://earthscience.stackexchange.com/a/5383/11908&quot;&gt;answer&lt;/a&gt; (in the comments) and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Fog&quot; rel=&quot;noreferrer&quot;&gt;fog wikipedia article&lt;/a&gt; mention that ice fog happens only at extremely low temperatures (-35 or -40 C). But I think I've experienced fog at those temperatures too. Some times, with the right light I've seen the air filled with tiny crystals, but I wouldn't call that fog, because it is very thin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then, as far as I can tell, all thick fogs feel and look the same. No matter if they are made out of ice crystals or water droplets. &lt;strong&gt;Is that right?&lt;/strong&gt; &lt;strong&gt;Or is there a way to differentiate between ice/water fogs?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or maybe contrary to what I think, I've never experienced frozen fog.&lt;br /&gt;&#xA;But: would I notice the difference if I were to ever experience it? How would they feel/look different?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, if somebody also knows why water droplets can stay liquid in clouds down to -30°C, it would be great to learn about that too.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="595" LastEditDate="2018-04-11T07:31:30.670" LastActivityDate="2019-03-14T17:33:22.457" Title="How to tell if fog is made out of water droplets or ice crystals?" Tags="|meteorology|clouds|ice|" AnswerCount="2" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="13834" PostTypeId="2" ParentId="13583" CreationDate="2018-04-07T17:00:44.767" Score="4" Body="&lt;p&gt;There are two physical processes at play here:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Wind speed relative to the ocean surface&lt;/li&gt;&#xA;&lt;li&gt;Wave focusing and blocking in opposing current&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h3&gt;Wind speed relative to the ocean surface&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;As you describe in your question, wind speed relative to the ocean surface varies depending on the current orientation and magnitude. The rate of wave growth is proportional to the wind speed $U$ in direction of the wave relative to the phase speed of the wave $c_p$, squared:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;S_{in} \sim \left( U - c_p \right)^2&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the wave phase speed is modulated by the current:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;c_p = c_{p0} + u &#xA;$$&#xA;where $c_{p0}$ is the intrinsic phase speed (phase speed in absence of currents) and $u$ is in the direction of the wave. Negative value of $u$ is then an opposing current. Wave growth is then:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;S_{in} \sim \left( U - c_{p0} - u \right)^2&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's plug in some numbers here. Let's say $U = 10\ m/s$, $c_{p0} = 3\ m/s$, and $u = \pm 1\ m/s$:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;In the case of following current, $u = 1\ m/s$, $S_{in} \sim 36\ m^2/s^2$ ;&lt;/li&gt;&#xA;&lt;li&gt;In the case of opposing current, $u = -1\ m/s$, $S_{in} \sim 64\ m^2/s^2$ ;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Thus, by changing the orientation of a moderate current in characteristic wind and wave conditions, we increased the rate of wave growth by a factor of 1.78! This effect will be more powerful the smaller the relative wind speed $U - c_{p0}$ is.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Wave focusing and blocking in opposing currents&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Wave energy is advected (transported) by the waves' own group speed $c_{g0}$ and also by currents. If for simplocity we drop all the other terms in the wave energy balance equation, we get:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$&#xA;\dfrac{\partial E}{\partial t} = -\dfrac{\partial \left[\left(c_{g0} + u \right)E\right]}{\partial x}&#xA;$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The crux here is in the modulated group speed $c_{g0} + u$. If the waves propagate into an area of increasingly stronger opposing current, there will be a convergence of wave energy in that space, which will manifest itself in increase of high and steep waves. At the point where $c_{g0} = -u$, that is, the current is exactly countering the group speed of the waves, they can no longer propagate in that direction! Wave energy accumulates locally and vigorous wave breaking ensues.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Summary&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Wave blocking is a different process from the wave growth dependence on relative wind speed described above, but, they often correlate because young windsea (short waves locally generated by wind) are almost always aligned with wind direction, so all you need is the currents to oppose wind for both of these effects to come into play at the same time. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both are likely to occur in strong and steady western boundary currents such as the Gulf Stream, Kuroshio, Aghulas, and Brazil current, and also in any region with strong tidal currents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More on this topic in the answer to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2860/what-visual-wave-behaviour-help-to-tell-if-a-tide-is-going-in-or-out&quot;&gt;this question&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="192" LastActivityDate="2018-04-07T17:00:44.767" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13836" PostTypeId="2" ParentId="13828" CreationDate="2018-04-08T10:30:37.860" Score="5" Body="&lt;p&gt;In answering this complex question, I think it's important to consider the form of carbon that is utilized and the overall reactions involved (warning: somewhat lengthy diversion ahead, and advance apologies if such is already understood by this audience). In the long-term carbon cycle, atmospheric &lt;span class=&quot;math-container&quot;&gt;$\ce{CO_{2(g)}}$&lt;/span&gt; drives weathering on land, importantly of silicates. &lt;span class=&quot;math-container&quot;&gt;$\ce{CO_{2(g)}}$&lt;/span&gt; dissolves in pure water forming (&lt;span class=&quot;math-container&quot;&gt;$\ce{CO_{2(aq)}}$&lt;/span&gt;), which can react with water to form carbonic acid (&lt;span class=&quot;math-container&quot;&gt;$\ce{H_2CO_{3(aq)}}$&lt;/span&gt;):&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ \ce{CO_{2(g)} + {H_{2}O_{(l)}}  &amp;lt;=&amp;gt; {H_2CO_{3(aq)}} }$$&lt;/span&gt;&#xA;but true carbonic acid is unstable, and the vast majority of this total dissolved carbon is thus present as dissolved molecular &lt;span class=&quot;math-container&quot;&gt;$\ce{CO_{2(aq)}}$&lt;/span&gt;, with concentrations obeying the simple &lt;a href=&quot;https://en.wikipedia.org/wiki/Henry%27s_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Henry's law&lt;/a&gt; relation (not shown). We can write this net reaction as:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ \ce{CO_{2} + {H_{2}O}  &amp;lt;=&amp;gt; {H_2CO_{3(aq)}} &amp;lt;=&amp;gt; H^{+}_{(aq)} + HCO_^{-}_{3(aq)} }$$&lt;/span&gt;&#xA;Bicarbonate also reflects the association/dissociation reaction involving pure carbonate ion,&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\ce{H^{+} + CO_^{2-}_{3} &amp;lt;=&amp;gt; HCO_^{-}_{3}}&#xA;$$&lt;/span&gt;&#xA;Weathering of a continental silicate, e.g., a normative wollastonite (chosen for simplicity), can thus be written as&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\ce{ CaSiO_3 + H_{2}O +2CO_{2} -&amp;gt; 2 HCO_^{-}_{3} + Ca^{2+} + SiO_{2}}&#xA;$$&lt;/span&gt;&#xA;The important point is that the dissolved carbon delivered to seawater by continental weathering is as bicarbonate, and surface seawater pH (&lt;span class=&quot;math-container&quot;&gt;$\sim 8)$&lt;/span&gt; in approximate equilibrium with atmospheric &lt;span class=&quot;math-container&quot;&gt;$\ce{CO_{2}}$&lt;/span&gt; indeed reflects this distribution of dissolved species. If we write the equilibrium for skeletal calcium carbonate as&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\ce{ CaCO_{3} &amp;lt;=&amp;gt; CO_^{2-}_{3} + Ca^{2+}}$$&lt;/span&gt;&#xA;we can combine the above equations to give the overall reaction for the dissolution/precipitation of &lt;span class=&quot;math-container&quot;&gt;$\ce{CaCO_3}$&lt;/span&gt; in seawater (incorporating the mass balance on &lt;span class=&quot;math-container&quot;&gt;$\ce{CO_2}$&lt;/span&gt; from reactions 1., 2., 3., and 5.) as,&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\ce{CaCO_{3} + H_{2}O + CO_{2} = Ca^{2+} + 2HCO_^{-}_{3} }&#xA;$$&lt;/span&gt;&#xA;Thus in this context, an important result is that, in the overall mass balance associated with precipitation of &lt;span class=&quot;math-container&quot;&gt;$\ce{CaCO_{3}}$&lt;/span&gt; (i.e., driving the above reaction to the left), &lt;span class=&quot;math-container&quot;&gt;$\ce{CaCO_{3}}$&lt;/span&gt; serves as a source, not a sink of carbon, because it liberates one mole of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO_2}$&lt;/span&gt; originally delivered as bicarbonate to seawater from silicate weathering. In the larger view (long term geochemical cycling), marine carbonates are a temporary sink for carbon that is ultimately subducted and returned to the atmosphere by vulcanism and other magmatic processes. The carbonates residing on the continents today (e.g., Paleozoic) have, in contrast, a much longer residence or cycling time that their modern pelagic equivalents.&lt;/p&gt;&#xA;&lt;p&gt;Now, to your question: ocean acidification (titration of seawater by atmospheric &lt;span class=&quot;math-container&quot;&gt;$\ce{CO_2}$&lt;/span&gt;, driving the last reaction to the right) per se is buffered by the attack of this sink of &lt;span class=&quot;math-container&quot;&gt;$\ce{CaCO_3}$&lt;/span&gt; producing more bicarbonate. Sequestration of carbon by growing shellfish will, according to the above, consume (some of) this bicarbonate, and produce &lt;span class=&quot;math-container&quot;&gt;$\ce{CO_2}$&lt;/span&gt; as a result. The larger, key question to me, is the rate at which the existing store of sedimentary &lt;span class=&quot;math-container&quot;&gt;$\ce{CaCO_3}$&lt;/span&gt;, particularly in surface water where it is being formed, dissolves in response to this attack.&lt;/p&gt;&#xA;" OwnerUserId="12611" LastEditorUserId="6298" LastEditDate="2021-09-18T10:08:18.680" LastActivityDate="2021-09-18T10:08:18.680" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="13838" PostTypeId="1" AcceptedAnswerId="13846" CreationDate="2018-04-08T15:30:50.440" Score="7" ViewCount="320" Body="&lt;p&gt;Do we have any knowledge about the age of Chile's fjords, more specifically, those found near the Northern Patagonian Ice Field?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it reasonable to conclude that they were formed in Quaternary given the fact that there exist glaciers there at this point in time?&lt;/p&gt;&#xA;" OwnerUserId="11459" LastEditorUserId="11908" LastEditDate="2019-04-06T20:04:40.900" LastActivityDate="2022-09-13T18:51:12.840" Title="How old are Chile's fjords?" Tags="|geology|glaciology|geomorphology|ice-age|glaciation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13840" PostTypeId="1" AcceptedAnswerId="13841" CreationDate="2018-04-08T19:35:21.407" Score="21" ViewCount="7922" Body="&lt;p&gt;The text of the introduction to the BBC Podcast &lt;a href=&quot;https://www.bbc.co.uk/programmes/w3csxfl2#play&quot; rel=&quot;noreferrer&quot;&gt;Sea Levels Rise; The Compass, Living on the Edge Episode 1 of 4&lt;/a&gt; says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Five of the Solomon Islands have disappeared&lt;/strong&gt;, many more are becoming uninhabitable. For Kerry and Sally, climate change is not a theory - it is what has made them abandon their island and the graves of their ancestors. They see themselves as lucky - they had family land to move to and the skills to build new homes on stilts - but they are resigned to moving again.&lt;/p&gt;&#xA;&lt;p&gt;Award-winning journalist Didi Akinyelure visits her home city of Lagos to find out the latest solution to sea level rise in West Africa. The glass towers of the new financial district of Eko Atlantic are protected from the waves by state of the art sea defences. The residents of the luxury apartments should keep their feet dry whatever the climate throws at them. That may be small comfort for their unprotected neighbours in the shanty town on the lagoon, Makoko, but they’re experts in survival against the odds.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Certainly sea level is rising, on the order of perhaps 15 centimeters in the last century judging from &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Trends_in_global_average_absolute_sea_level,_1880-2013.png&quot; rel=&quot;noreferrer&quot;&gt;this plot&lt;/a&gt;, and the New Scientist article &lt;a href=&quot;https://www.newscientist.com/article/2087356-five-pacific-islands-vanish-from-sight-as-sea-levels-rise/&quot; rel=&quot;noreferrer&quot;&gt;Five Pacific islands vanish from sight as sea levels rise&lt;/a&gt; certainly adds credence to this. Answers to the question &lt;a href=&quot;https://earthscience.stackexchange.com/q/9163/6031&quot;&gt;Sea Level Rise due to Climate Change&lt;/a&gt; shed some light on human-induced climate change.&lt;/p&gt;&#xA;&lt;p&gt;Between about 04:00 and 06:00 in the podcast, &lt;a href=&quot;https://marine.uq.edu.au/content/dr-simon-albert&quot; rel=&quot;noreferrer&quot;&gt;Simon Albert&lt;/a&gt;, a climate change scientist from University of Queensland describes the situation in the Solomons.&lt;/p&gt;&#xA;&lt;p&gt;Here is my best attempt at a transcription of a small part of the podcast:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Solomons have really over the last couple of decades been a global “hot spot” for sea level rise. So the rates of sea level rise we’ve observed in the Solomons have been in the order of three times the global average.&lt;/p&gt;&#xA;&lt;p&gt;Whilst globally the seas have been rising approximately 3 millimeters per year for the last couple of decades, the Solomons have seen a rise of 7 to 10 millimeters per year over that time frame.&lt;/p&gt;&#xA;&lt;p&gt;A large part of that is a result of human-induced climate change, and then on top of that we’ve also had “the perfect storm” if you like, of a series of natural cycles in sea-level rise and weather conditions, such as El Nino, intensification of trade winds, which effectively have pushed water into the Western Pacific, resulting in a significantly higher than would be normally experienced.&lt;/p&gt;&#xA;&lt;p&gt;Over the last 20 years we’ve seen sea level in the Solomons rise by 15 to 20 centimeters. When you translate that over these very low-lying islands, that can translate to the coast line receding by several hundreds of meters.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Could someone help me better understand the phenomenon that have lead to this faster rate of local sea level rise in the Solomon islands?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;edit:&lt;/strong&gt; My original post had these four points. Once I replayed a few more times I realized they don't perfectly reflect the breakdown in the podcast, but since @John has taken the time to write such a great answer using them I'll include them here to maintain continuity:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Human induced climate change&lt;/li&gt;&#xA;&lt;li&gt;Series of natural cycles in sea level rise&lt;/li&gt;&#xA;&lt;li&gt;Weather cycles such as El Niño&lt;/li&gt;&#xA;&lt;li&gt;Intensification of trade winds, which have pushed water into the pacific&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; The sea encroaches on a tropical island. Credit: Getty Images. From &lt;a href=&quot;https://www.bbc.co.uk/programmes/w3csxfl2#play&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;. (click for full size)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UD4vZ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UD4vZ.jpg&quot; alt=&quot;Solomon Islands&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; Credit: Chris Roelfsema, from &lt;a href=&quot;https://i.stack.imgur.com/UD4vZ.jpg&quot; rel=&quot;noreferrer&quot;&gt;NewScientist&lt;/a&gt;. (click for full size)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kGLaY.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kGLaY.jpg&quot; alt=&quot;Solomon Islands&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-04-11T00:43:04.140" Title="&quot;Five of the Solomon Islands disappeared&quot; due to sea level rise, how is this possible so quickly?" Tags="|climate-change|sea-level|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13841" PostTypeId="2" ParentId="13840" CreationDate="2018-04-08T20:43:38.193" Score="26" Body="&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;&lt;p&gt;The sea is not the only thing that rises, the sea floor can also rise and fall in accordance with the underlying geology. Oceanic tectonic plates sink as they age (and thus get colder and denser), the Solomon islands happen to be on a  sinking section of the ocean floor and at the same time the sea level is rising. Keep in mind many of those islands have a very shallow slope, so a few rising millimeters are many feet of inland horizontal motion. Of course once the wave base reaches  new &quot;virgin&quot; sediment (often loose sand), it often washes it away moving the tide line even further inland. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Storms cause a storm surge which can wash away sediment. A rising sea level means the storm surge is reaching sediments they could not reach before, so they are causing faster erosion. In addition, salt water kills a lot of plants further eroding the sediment, so a higher surge means more dead plants and more settling of sediment. Storms can cause a tremendous amount of erosion on unprotected soil, a single storm washed away two entire city blocks in the Atlantic City history. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;I am not entirely sure, but prevailing winds can cause some displacement of water (the ocean is not completely leveled because it is moving) so a change in the trade winds could lead to a minor effect of local sea level, how much this contributes, I have no idea.  &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Note&lt;/em&gt;: the OP started with a numbered list and specifically asked about the highlighted numbers, hence only 2-4 were referenced in my answer (the first one was a normal sea level rise). &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="12622" LastEditDate="2018-04-09T11:54:44.020" LastActivityDate="2018-04-09T11:54:44.020" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13844" PostTypeId="1" CreationDate="2018-04-09T15:02:48.817" Score="1" ViewCount="41" Body="&lt;p&gt;As the interior of the earth cools, presumably there will come a time when the temperature gradient is insufficient to maintain the mantle plumes and hence plate tectonics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How long will this take and what will be the consequences for the surface of the planet in terms of continent and ocean distribution and depths. Will it also affect the recycling of gases etc into the atmosphere?&lt;/p&gt;&#xA;" OwnerUserId="12625" LastEditorUserId="6298" LastEditDate="2018-04-09T22:36:40.610" LastActivityDate="2018-04-09T22:36:40.610" Title="How long will it take for plate tectonics to shut down and what will the effects be?" Tags="|geology|planetary-science|" AnswerCount="0" CommentCount="1" ClosedDate="2018-04-10T10:58:00.530" ContentLicense="CC BY-SA 3.0" />
  <row Id="13845" PostTypeId="2" ParentId="13840" CreationDate="2018-04-09T16:08:31.917" Score="9" Body="&lt;p&gt;Sea level rise is faster in the western tropical Pacific than anywhere else, and a principal reason for this is the intensifying easterly trade winds over the tropical Pacific during the last two decades (see &lt;a href=&quot;https://sealevel.nasa.gov/understanding-sea-level/causes/regional-sea-level-change&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;).  Note that this phenomenon is not necessarily separate or distinct from human-caused climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The role of the El Niño Southern Oscillation has to do with increased rainfall over the sea (as opposed to over land) in Niño years.  During Niña years, with increased rainfall overland (as opposed to over the ocean), water is temporarily stored on land, and this effect is strongest in tropical regions.  However, there does not appear to be any long-term trend arising from this forcing.&lt;/p&gt;&#xA;" OwnerUserId="12628" LastEditorUserId="12628" LastEditDate="2018-04-11T00:43:04.140" LastActivityDate="2018-04-11T00:43:04.140" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13846" PostTypeId="2" ParentId="13838" CreationDate="2018-04-09T19:33:19.277" Score="6" Body="&lt;p&gt;The Quaternary is definitely a good guess. But it is difficult to answer your question because the &quot;age of a fjord&quot; is a rather ambiguous concept. &#xA;Also, I'll asume you are interested in the bedrock topography associated  to the fjords, and not only the sea inlets (as in that case they would have formed very recently, just when the glaciers receded enough to allow the ocean water to take their place). With that said let's try to answer the question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fjords of western Patagonia are a feature created by the Pleistocene glaciations, therefore you can definitely say that the fjords as a feature of the landscape were formed during the Quaternary. However, they are in constant evolution, so you can arguably also say that the fjords as you see them today, were formed today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Glacier erosion rates in Patagonia range roughly from a few tenths of millimeters to a few centimeters per year. Faster rates probably happening at the edges of the ice sheets were glacier basal sliding velocities are higher. Long term averages (~10 ka) are probably between &lt;a href=&quot;https://www.researchgate.net/publication/235711943_Timescale_dependence_of_glacial_erosion_rates_A_case_study_of_Marinelli_Glacier_Cordillera_Darwin_southern_Patagonia&quot; rel=&quot;nofollow noreferrer&quot;&gt;0.5 mm/yr&lt;/a&gt; and &lt;a href=&quot;https://www.researchgate.net/publication/215614431_The_relative_efficacy_of_fluvial_and_glacial_erosion_over_modern_to_orogenic_timescales&quot; rel=&quot;nofollow noreferrer&quot;&gt;1 mm/yr&lt;/a&gt;, meaning that in the 2.6 Ma of the Quaternary you would erode just about one to two kilometers. As some fjords can be much deeper than that (when measured from the mountain tops), it is clear that the fjords as a geographical feature &lt;strong&gt;are not in steady state&lt;/strong&gt;, and they are now more dramatic than ever throughout the Quaternary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MRfST.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MRfST.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;em&gt;Erosion rates measured in outlet glaciers in Patagonia and other areas in different timescales. From figure 2.a in &lt;a href=&quot;https://www.researchgate.net/publication/215614431_The_relative_efficacy_of_fluvial_and_glacial_erosion_over_modern_to_orogenic_timescales&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;The relative efficacy of fluvial and glacial erosion over modern to orogenic timescales&quot;&lt;/a&gt; 2009, Nature Geoscience 2(9):644-647.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason that explain why Fjords can become deeper than that one kilometer estimate, is the concentrated erosión in outlet glaciers at the edge of the ice sheet. For example, the most visited glacier in the Northern Patagonian Icefield: the San Rafael glacier, show &lt;a href=&quot;https://www.researchgate.net/publication/289685004_Latitudinal_variation_in_glacial_erosion_rates_from_Patagonia_and_the_Antarctic_Peninsula_46S-65S&quot; rel=&quot;nofollow noreferrer&quot;&gt;erosion rates of 0.83 mm/year&lt;/a&gt;. And as shown in the figure above, outlet glaciers can erode up to ~5 cm/yr at shorter timescales.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Sumarizing:&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Northern Patagonian Ice Field's fjords started to form with the first Pleistocene glaciation at the begin of the Quaternary about 2.6 million years ago, but they have become deeper after each successive glaciation and they are still forming today. Current glaciers are eroding their bedrock at rates on the order of one to a few centimeters per year.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-04-10T17:51:33.673" LastActivityDate="2018-04-10T17:51:33.673" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13848" PostTypeId="1" AcceptedAnswerId="13853" CreationDate="2018-04-09T21:40:58.103" Score="8" ViewCount="202" Body="&lt;p&gt;I've noticed many reports in the media about the East African Rift Valley recently, apparently because some large fissures opened up. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Washington Post: &lt;a href=&quot;https://www.washingtonpost.com/national/health-science/a-huge-crack-provides-evidence-that-africa-is-slowly-splitting-into-two/2018/04/06/0b9a5144-3749-11e8-acd5-35eac230e514_story.html&quot; rel=&quot;noreferrer&quot;&gt;A huge crack provides evidence that Africa is slowly splitting into two&lt;/a&gt;&lt;br&gt;&#xA;CNN: &lt;a href=&quot;https://www.cnn.com/2018/04/05/africa/crack-africa-rift-valley-continent-splitting-two/&quot; rel=&quot;noreferrer&quot;&gt;Big crack is evidence that East Africa could be splitting in two&lt;/a&gt;&lt;br&gt;&#xA;Fox News: &lt;a href=&quot;http://www.foxnews.com/science/2018/04/09/africa-is-splitting-in-two-and-heres-proof.html&quot; rel=&quot;noreferrer&quot;&gt;Africa is splitting in two, and here's proof&lt;/a&gt;&lt;br&gt;&#xA;USA Today: &lt;a href=&quot;https://www.usatoday.com/story/news/2018/04/04/breaking-up-hard-do-africa-could-eventually-split-into-two-continents/485321002/&quot; rel=&quot;noreferrer&quot;&gt;Breaking up is hard to do: Africa could eventually split into two continents&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many of them seem to suggest that this is significant new evidence that Africa is going to split in two, but my understanding was that this was not at all in question and hasn't been for quite some time.  Is this just a case of science journalism exaggerating things as it often does or is there something significant in that the existence of these two plates diverging was less firmly established than I thought or that these recent events have significantly changed our understanding of them that justifies all the hoopla, but is not being adequately conveyed.&lt;/p&gt;&#xA;" OwnerUserId="582" LastEditorUserId="6298" LastEditDate="2018-04-10T05:53:00.890" LastActivityDate="2018-04-10T12:39:43.680" Title="Has our understanding of the East African Rift significantly changed recently?" Tags="|plate-tectonics|east-africa-rift|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13849" PostTypeId="2" ParentId="7212" CreationDate="2018-04-09T23:03:38.150" Score="1" Body="&lt;p&gt;Whether and how long it takes a pond or other body of water to freeze depends on several factors.  Air Pressure, TDS (total dissolved solids, or salts), motion of the water itself and the temperature of the surrounding environment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Air Pressure - Mostly a function of altitude, the pressure of the air effect the pressure of the water , with water under higher pressure requiring lower temperatures to freeze.  &lt;a href=&quot;https://physics.stackexchange.com/questions/60170/freezing-point-of-water-with-respect-to-pressure&quot;&gt;https://physics.stackexchange.com/questions/60170/freezing-point-of-water-with-respect-to-pressure&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;TDS - Total dissolved solids, mostly salts and other ions lower the freezing point of water up to a point and depending on the specific chemicals and concentration dissolved.  In fresh water ponds this is unlikely to mean more than 1 or 2 degrees difference.  &lt;a href=&quot;https://www.troublefreepool.com/threads/17456-Quantifying-TDS-constituents-affect-on-freezing-point-of-H20&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.troublefreepool.com/threads/17456-Quantifying-TDS-constituents-affect-on-freezing-point-of-H20&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Motion of the water.  Moving water tends to inhibit ice crystal formation and delay freezing.  &lt;a href=&quot;https://www.physicsforums.com/threads/temperature-needed-to-freeze-moving-water.515414/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.physicsforums.com/threads/temperature-needed-to-freeze-moving-water.515414/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Temperature of the surrounding environment.  In general with outdoor water like ponds and lakes, the ground underneath the body of water will remain close to the average yearly temperature.  The air above the pond will have to remove enough heat from the pond to overcome all these factors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Water also has the unique(?) property of decreasing in density as it freezes.  This means that ice, which forms will form at the surface where the water tends to be warmer to begin with.  In the liquid portion of the pond, convection will bring heat from the earth under the pond to the surface, which delays ice formation.  The cold water moving down tot he bottom is subjected to increasign pressure, lowerign its freezing point, so that even once it reqaches the freezing point at the surface, it will not freeze as it moves down towards the warm earth.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The net effect of all this is that the entire body of water must reach the freezing point before ice will be able to form.  The deeper the pond/lake, the longer it takes and a deep enough body of water will never completely freeze under normal earth conditions.  As the ice layer forms on the surface, it acts to insulate the water below it, reducing the amount of heat the air can remove, but the ice doesn't form on the pond bottom, so it continues to receive heat from the earth.  So the pond never fully freezes if it is deep enough and the winter short enough.&lt;/p&gt;&#xA;" OwnerUserId="12633" LastActivityDate="2018-04-09T23:03:38.150" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13850" PostTypeId="2" ParentId="7212" CreationDate="2018-04-10T01:13:38.933" Score="6" Body="&lt;p&gt;The variable you need to consider to understand the problem is the pond's depth. I bet that in contrast to your pond, shallow puddles around did freeze.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The water is denser at 4°C, so to freeze the surface you need to cool down the whole pond to 4°C.&#xA;Otherwise, when water in the surface cools down to 4°C, it would sink and be replaced by warmer water from below, then if that water is cooled down to 4°C it will sink again and be replaced by warmer water, and so on. Only once the whole pond is at 4°C, the water in the surface can cool down below that temperature and still be lighter that the water below, therefore it would stay in the surface and can keep cooling down until it freezes producing a layer of surface ice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following figure from &lt;a href=&quot;http://wtamu.edu/~cbaird/sq/2013/12/05/why-does-ice-form-on-the-top-of-a-lake/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this question&lt;/a&gt; at &quot;Science questions with surprising answers&quot; shows the temperature stratification differences of a warm pond (summer figure), and one just cold enough to start the formation of a surface ice crust (winter figure).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KwPCF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KwPCF.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The time required to cool down the whole body of water is then proportional to depth. Shallow water bodies will freeze easier, and deep ones will require extended periods of below freezing temperatures to start generating a frozen crust.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-18T03:15:30.757" LastActivityDate="2019-02-18T03:15:30.757" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="13851" PostTypeId="1" CreationDate="2018-04-10T02:52:39.907" Score="10" ViewCount="220" Body="&lt;p&gt;Ammonia is the only alkaline gas in the atmosphere. It is one of the key features to control the acidity of aerosols and the formation of ammonium salts. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the environment of $NH_3$-rich and $NH_3$-poor, the formation pathway of the secondary aerosol would be distinct.     &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;For example, if $NH_3$ is redundant after the combination with $_2SO_4$, they would continue to react with $HNO_3$ to form $NH_4NO_3$. However, if in the $NH_3$-poor environment, $HNO_3$ would react with the crustal material and thus form nitrate in the coarse mode.   &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;In this way, the concentration levels of $NH_3$ affect the chemical composition, size distribution of atmospheric aerosols.   &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, the ground-level monitoring of $NH_3$ is still limited in China with several published ones in limited spots. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, I want to learn that:   &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Is there any method to estimate NH3 concentration by other species?     &lt;/li&gt;&#xA;&lt;li&gt;Is there any dataset (e.g. remote sensing, measurements) offering the distribution of $NH_3$ concentration?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="5594" LastEditDate="2018-04-10T07:53:51.547" LastActivityDate="2018-05-03T04:45:25.873" Title="A rough picture about the ground-level ammonia (NH3)" Tags="|atmosphere|remote-sensing|atmospheric-chemistry|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13853" PostTypeId="2" ParentId="13848" CreationDate="2018-04-10T12:39:43.680" Score="9" Body="&lt;p&gt;tl;dr&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Has our understanding of the East African Rift significantly changed recently?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;We already know that it is splitting&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The headlines suggest that the fact there is splitting (i.e. a rift) is a &quot;maybe&quot;: &quot;&lt;em&gt;East Africa could be splitting in two&lt;/em&gt;&quot;, &quot;&lt;em&gt;Africa could eventually split into two continents&lt;/em&gt;&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We already &lt;a href=&quot;http://www.annualreviews.org/doi/pdf/10.1146/annurev.ea.15.050187.002305&quot; rel=&quot;noreferrer&quot;&gt;know&lt;/a&gt; that it is splitting. There is plenty of evidence for that happening from a variety of fields in geoscience. GPS measurements, geodesy and kinematics &lt;a href=&quot;https://doi.org/10.1029/2007GL032781&quot; rel=&quot;noreferrer&quot;&gt;tell us&lt;/a&gt; how fast it is splitting. The type of magma erupted in volcanoes located in the rift is consistent with what you would expect in a rift (alkaline volcanism and carbonatites). We &lt;a href=&quot;https://doi.org/10.1016/S0012-821X(00)00012-1&quot; rel=&quot;noreferrer&quot;&gt;know&lt;/a&gt; that there's a mantle plume below the rift, which is one of the causes of the rifting. We can even &lt;a href=&quot;https://doi.org/10.1002/2015GC005948&quot; rel=&quot;noreferrer&quot;&gt;see it&lt;/a&gt; with deep earth geophysics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The Kenya crack is not because of said splitting&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;apparently because some large fissures opened up. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The crack in Kenya is not the result of this rifting. The &lt;a href=&quot;https://www.theguardian.com/science/blog/2018/apr/06/africa-is-slowly-splitting-in-two-but-this-crack-in-kenya-rift-valley-has-little-to-do-with-it&quot; rel=&quot;noreferrer&quot;&gt;link&lt;/a&gt; provided by JeopardyTempest in the comments is an excellent summary of what it is: erosion caused by heavy rains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will note though that some people suggested the crack to follow a pre-existing fault line, so splitting and earthquakes in the past may have formed a &quot;weak spot&quot; for the erosion to occur, but the erosion itself did was not triggered by any seismic or tectonic activity.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-04-10T12:39:43.680" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13854" PostTypeId="1" AcceptedAnswerId="13857" CreationDate="2018-04-10T20:27:53.710" Score="30" ViewCount="21952" Body="&lt;p&gt;Are there places on Earth that have a strong magnetic field other than the magnetic north and south poles?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/17611/can-living-where-rare-earth-magnetic-ore-is-abundant-provide-a-mini-magnetoshe&quot;&gt;Can living where (rare) earth magnetic ore is abundant provide a mini-magnetoshere?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2019-08-03T20:25:45.933" LastActivityDate="2019-08-03T20:25:45.933" Title="Where on Earth is the magnetic field intensity stronger?" Tags="|geophysics|geomagnetism|mapping|natural-conditions|field-measurements|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="13855" PostTypeId="1" AcceptedAnswerId="13858" CreationDate="2018-04-10T21:12:47.423" Score="5" ViewCount="22179" Body="&lt;p&gt;The residence time for an element in a reservoir can be calculated by the reservoir size at steady state divided by the inflow or outflow rate. Given the following diagram, I need to calculate the mean residence times for nitrogen in the following stocks:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Atmosphere&lt;/li&gt;&#xA;&lt;li&gt;Fixed Nitrogen on Land&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aA2E2.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aA2E2.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I am confused by this question, what exactly is its steady state? what exactly is the reservoir size and what it the inflow and outflow?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: Problem-solved with the help of Camilo Rada. The way you calculate residence time is by using the formula:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\text{Residence time} = \frac{\text{Reservoir size}}{\text{in-flow or outflow rate}}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the example I looked at the box in the diagram for atmosphere's content of residence, being $3 \times 10^{20}$ units, that will serve as our total reservoir size, then we can either choose the outgoing or incoming flow (as an approximation as the reservoir is not in steady state), I chose the outgoing, so we add them together: $7 \times 10^{12} + 7 \times 10^{12} = 14 \times 10^{12}$ units per year. Now plug that into the formula:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$RT_{ATMO} = \frac{3 \times 10^{20}}{14 \times 10^{12}} = 21,428,571 \, \text{years} = \, \backsim 21 \, \text{million years}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It would be the same process for each box.&lt;/p&gt;&#xA;" OwnerUserId="12218" LastEditorUserId="11908" LastEditDate="2018-04-11T02:06:14.813" LastActivityDate="2018-08-14T17:53:27.043" Title="How to calculate residence time for an element in a reservoir?" Tags="|atmosphere|geography|homework|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13857" PostTypeId="2" ParentId="13854" CreationDate="2018-04-10T22:20:13.477" Score="42" Body="&lt;p&gt;If we consider only the magnetic field generated by natural sources, and not the ones generated by human activities. The general trend is that higher intensities of the magnetic field happen close to the magnetic poles. However, this is just a general trend. The southern hemisphere experiences the highest magnetic fields intensities, reaching over 65,000 nT, and this southern maximum matches fairly well with the south magnetic pole. In contrast, in the northern hemisphere, the maximum happens in Siberia, quite far from the north magnetic pole &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_magnetic_field&quot; rel=&quot;nofollow noreferrer&quot;&gt;that is currently very close to the geographic north pole&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are many models of Earth's magnetic field. You can find a comprehensive list at &lt;a href=&quot;http://geomag.org/models/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;geomag.org&lt;/a&gt;. You can find the intensity output of &lt;a href=&quot;https://ngdc.noaa.gov/geomag/WMM/DoDWMM.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA's World Margentic Model&lt;/a&gt; for 2015, &lt;a href=&quot;https://ngdc.noaa.gov/geomag/WMM/data/WMM2015/WMM2015_F_MERC.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. Shapefiles with the contours are available for 2018 &lt;a href=&quot;https://ngdc.noaa.gov/geomag/WMM/image.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; (as well as more maps), and the coordinates of north and south poles computed by the WMM model up to 2020 are available &lt;a href=&quot;https://www.ngdc.noaa.gov/geomag/GeomagneticPoles.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. Putting together all the information for 2018, the map looks like this&#xA;&lt;a href=&quot;https://i.stack.imgur.com/dVdvt.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dVdvt.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The contour interval is 1000 nT, grid lines interval is 10°, and the green dots represent the south and north magnetic poles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The maximum intensity contour in the northern hemisphere happens in Siberia with a value of 61,000 nT and the center of the contour is located roughly 3,100 km away from the magnetic north pole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The maximum intensity contour in the southern hemisphere is between Australia and Antarctica, with a value of 67,000 nT and the center of the contour is located roughly 450 km away from the magnetic south pole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the answer is: &lt;strong&gt;Yes, there are. Maximum field intensity doesn't happen at the magnetic poles. Specially in the Northern hemisphere, the maximum intensity happens in Siberia, a few thousand kilometers away from the magnetic pole. The maximum intensity globally according to NOAA's WMM model is located in the southern hemisphere, approximately at 60° 15' S, 135° 52' E, about 450 km away from the south magnetic pole&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The projection in the map above (geographic) generates a big distortion of the distances, the images below show the same information in polar stereographic projection:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/U73Iz.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/U73Iz.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, it is worth adding that the above information wouldn't be significantly modified if you consider natural magnetic anomalies due to magnetic crustal deposits. This is because magnetic anomalies are usually smaller than a few hundred nT, therefore the magnetic field intensity pattern is largely controlled by the internal magnetic field. Magnetic anomalies are not mapped over the whole world, but the &lt;a href=&quot;http://geomag.org/models/wdmam.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;World Digital Magnetic Anomaly Map&lt;/a&gt;, provides a pretty good estimate &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wCB5v.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wCB5v.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, these anomalies are measured  at an altitude of 5 km above mean sea level, and have a resolution of 3-arc-minute resolution (~5 km). Therefore, it doesn't rule out the existence of very strong and localized small scale anomalies, that might lead to large variations on the magnetic field intensity but over a very small area.&#xA;The maximum value within the World Digital Magnetic Anomaly Map dataset is 8570.78 nT, but even considering all anomalies, the largest field intensities remain within the same contour near the magnetic south pole.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-01-14T15:51:19.353" LastActivityDate="2019-01-14T15:51:19.353" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="13858" PostTypeId="2" ParentId="13855" CreationDate="2018-04-10T22:33:54.323" Score="4" Body="&lt;p&gt;Steady state is when the size of the reservoirs doesn't change with time (because inflow=outflow). The size of each reservoir is the number inside the boxes and the flow rates are the numbers beside the arrows.&#xA;If you calculate the total inflow/outflow from each reservoir, you can use the relationship you did enunciate at the start of the question to easily calculate residence times.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, according to the diagram those reservoirs are not in steady state. So either the question is ill posed, or you are supposed to make some approximations (or a more complex calculation, but I don't think that's the case).&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-04-10T22:48:43.463" LastActivityDate="2018-04-10T22:48:43.463" CommentCount="10" ContentLicense="CC BY-SA 3.0" />
  <row Id="13860" PostTypeId="2" ParentId="13831" CreationDate="2018-04-11T02:44:00.903" Score="2" Body="&lt;p&gt;Different size raindrops make different rainbows. Fog droplets make a colorless fog bow but frozen fog make unique colorful rainbows such as the one below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.metoffice.gov.uk/learning/clouds/fog/freezing-fog&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.metoffice.gov.uk/learning/clouds/fog/freezing-fog&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The picture below is an ice fog rain bow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to conclude Ice equals color and distinct rainbow pattern when it comes to fog. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/s8TLU.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/s8TLU.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;Diamond dust is what frozen fog is called.&#xA;&lt;a href=&quot;https://saebloom.wordpress.com/2016/12/13/diamondsnow/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://saebloom.wordpress.com/2016/12/13/diamondsnow/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/A3XIz.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/A3XIz.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;All the patterns are generated as sunlight (or moonlight) is reflected and refracted in flat six-sided water ice crystals in Earth's atmosphere.&#xA;&lt;a href=&quot;https://apod.nasa.gov/apod/ap181221.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://apod.nasa.gov/apod/ap181221.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found this picture of High clouds refracting light.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/OpO2q.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OpO2q.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.dkn.tv/tin-giai-tri/nhung-vang-hao-quang-ky-la-tren-bau-troi.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.dkn.tv/tin-giai-tri/nhung-vang-hao-quang-ky-la-tren-bau-troi.html&lt;/a&gt;&#xA;I could get my translator to work but just looking at the picture the sun is past the horizon of the camera but not the clouds and clouds that high is frozen creating a Fire Rainbow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wAy2w.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wAy2w.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://physics.stackexchange.com/questions/289279/why-is-each-snow-flake-different&quot;&gt;https://physics.stackexchange.com/questions/289279/why-is-each-snow-flake-different&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To add: You could use a telescope and angled white laser or focused light to synthesis a bow to see if it refracts differently between ice/color or liquid/no color and the pattern it makes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Added After Edit:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://contrailscience.com/aerodynamic-and-rainbow-contrails/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://contrailscience.com/aerodynamic-and-rainbow-contrails/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the contrail has refraction or rainbow it is ice. The pilot can turn the plane to the angle needed to see the rainbow from the cockpit. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VnkEh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VnkEh.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BtFPX.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BtFPX.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;Rain bow at night with spot light. &lt;a href=&quot;https://atoptics.wordpress.com/2017/02/05/binary-double-rainbows/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://atoptics.wordpress.com/2017/02/05/binary-double-rainbows/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this was ice or fog rather than rain the rainbow will be different in pattern and color. I am interested to try this with the whitest of light or maybe a white laser which does exist.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Last edit: I believe the sunlight is refracted inside the ice and is warmed because of that there must be a equilibrium between the cold air and ice to stay frozen during the day but at night the ice fog could be warmer. &#xA;I have not considered if the friction between the air and ice as a factor. &lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2019-03-14T17:33:22.457" LastActivityDate="2019-03-14T17:33:22.457" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="13862" PostTypeId="2" ParentId="13854" CreationDate="2018-04-11T09:20:53.737" Score="13" Body="&lt;p&gt;Since it is not specified in the question (and to complement the other answer), the strongest magnetic fields on Earth are not naturally generated, but artificially.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The current world record holder seems to be the National High Magnetic Field Laboratory (NHMFL) in Los Alamos, USA, &lt;a href=&quot;http://www.lanl.gov/science-innovation/features/science-digests/world-record-set-magnetic-field.php&quot; rel=&quot;noreferrer&quot;&gt;with a magnetic field strength of about 100T&lt;/a&gt; (so about two million times higher than the Earth's magnetic field). &lt;a href=&quot;https://www.quora.com/What-is-the-strongest-magnetic-field-ever-artificially-created&quot; rel=&quot;noreferrer&quot;&gt;This quora answer&lt;/a&gt; suggests that they have since increased it to 300T.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are a few other high magnetic field laboratories in the world, for example the Helmholtz-Zentrum Dresden-Rossendorf (HZDR) in Dresden, Germany, which briefly held the record before &lt;a href=&quot;https://www.popsci.com/science/article/2011-06/german-lab-generates-highest-magnetic-field-ever-created-lab&quot; rel=&quot;noreferrer&quot;&gt;with a field strength of 91.4T&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These magnets are usually pulsed magnets, so they cannot maintain the field strength for longer than a few milliseconds. For longer durations it seems like the MagLab in Florida, USA is currently holding the record &lt;a href=&quot;https://nationalmaglab.org/user-facilities/dc-field/instruments-dcfield/hybrid-magnets/45-tesla-2&quot; rel=&quot;noreferrer&quot;&gt;with a 45T magnet&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="12645" LastActivityDate="2018-04-11T09:20:53.737" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13865" PostTypeId="1" AcceptedAnswerId="13868" CreationDate="2018-04-11T19:48:14.943" Score="3" ViewCount="161" Body="&lt;p&gt;If you occasionally check the Weather Channel (either the smartphone app or online), you'll see they reference strong weather systems by name. (It only seems to be eastern storms.) I've always wondered if this was just something The Weather Channel does--for whatever reason--of if the NWS really does name them.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2018-04-12T21:14:40.960" Title="Does the NWS actually name winter storms, or is this exclusive to the Weather Channel?" Tags="|meteorology|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13867" PostTypeId="2" ParentId="13673" CreationDate="2018-04-11T22:38:26.220" Score="3" Body="&lt;p&gt;You can take a look at the Predictive Ecosystem Analyzer (PEcAn) - it is a statistical framework and workflow system that supports parameterization and analysis of a number of land surface, crop, and ecosystem models. It supports a half-dozen models and support for another half-dozen or so is planned.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mission of the project is to &quot;Develop and promote accessible tools for reproducible ecosystem modeling and forecasting&quot; You can learn more, find a demo, tutorials, documentation, and a virtual machine at the project home page: pecanproject.org. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can also find us on github.com/pecanproject and meet the community on &lt;a href=&quot;https://publicslack.com/slacks/pecanproject/invites/new&quot; rel=&quot;nofollow noreferrer&quot;&gt;Slack&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;disclaimer: I am a PI and developer on the project.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="174" LastActivityDate="2018-04-11T22:38:26.220" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13868" PostTypeId="2" ParentId="13865" CreationDate="2018-04-11T23:05:47.690" Score="4" Body="&lt;p&gt;It is just the Weather Channel. You can tell which businesses frequently watch (or even do business with) the Weather Channel by whether or not they refer to them by these names. The naming of winter storms irks many of the meteorologists I know (including myself).&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2018-04-11T23:05:47.690" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13869" PostTypeId="1" CreationDate="2018-04-11T23:28:56.687" Score="6" ViewCount="142" Body="&lt;p&gt;I've seen a few articles lately about research published in the Journal Science that concludes that 26% of the nitrogen in the ecosystem is from rock weathering.  These results seem to fill in a nitrogen gap when analyzing the amount of nitrogen in soil and plants from the atmosphere alone.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From here I've noticed a little bit of divergence in the reporting of the results from different sources.  The &lt;a href=&quot;https://www.eurekalert.org/pub_releases/2018-04/nsf-nso040918.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;American Association for the Advancement of Science (AAAS)&lt;/a&gt; article seems to basically just quote from the Journal Science article:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Geology might have a huge control over which systems can take up&#xA;  carbon dioxide and which ones can't,&quot; Houlton said. &quot;When thinking&#xA;  about carbon sequestration, the geology of the planet can help guide&#xA;  our decisions.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://phys.org/news/2018-04-source-global-nitrogen.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Phys.Org&lt;/a&gt; article includes another quote from one of the authors:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Our study shows that nitrogen weathering is a globally significant&#xA;  source of nutrition to soils and ecosystems worldwide,&quot; said co-lead&#xA;  author Ben Houlton, a professor in the UC Davis Department of Land,&#xA;  Air and Water Resources and director of the UC Davis Muir Institute.&#xA;  &quot;This runs counter the centuries-long paradigm that has laid the&#xA;  foundation for the environmental sciences. We think that this nitrogen&#xA;  may allow forests and grasslands to sequester more fossil fuel CO2&#xA;  emissions than previously thought.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I also found this in an article from &lt;a href=&quot;https://currentaffairs.gktoday.in/earths-bedrock-source-global-nitrogen-discovered-04201854222.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;currentaffairs.gktoday.in&lt;/a&gt; where the lead paragraph, without a citation, concludes with:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This study could greatly improve climate change projections.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I do realize that some news organizations and publications will over-exaggerate these results, and some may try to ignore these results, based on their political views (and possibly those of their audiences).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What I would like to know is whether or not nitrogen weathering from rocks would change any of the projections of climate models, and if so how?&lt;/strong&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Update:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I came across a &lt;a href=&quot;https://cen.acs.org/environment/climateChange/Rocks-missing-piece-nitrogen-cycle/96/i15&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chemical &amp;amp; Engineering article&lt;/a&gt; with statements from two biogeochemists on the implications of these findings.  One states that constraints on plant growth under high CO2 conditions may not be as large as we think with the knowledge of this addition nitrogen source.  One the other hand, the other states that nitrogen from rock weathering is likely too small on a global scale to make a difference that would fall outside the margin of error of current climate models.  Perhaps it's just too soon to tell what the implications may be.   &lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastEditorDisplayName="user11318" LastEditDate="2018-04-13T21:24:46.877" LastActivityDate="2018-04-13T21:24:46.877" Title="Will the recent findings regarding nitrogen rock weathering alter climate change projections?" Tags="|climate-change|climate|nitrogen|" AnswerCount="0" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13872" PostTypeId="1" AcceptedAnswerId="13873" CreationDate="2018-04-12T03:16:20.023" Score="-2" ViewCount="125" Body="&lt;p&gt;If we had a heat bank account (the atmosphere)&lt;br /&gt;&#xA;          + heat cash supply (ice)&lt;br /&gt;&#xA;          + heat debt (the oceans)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;could governments find a way to balance our heat economy that doesn't kill everything? I think I'd rather have Mother Nature fix it, but we need to be ready for her mood swings (hurricanes, wind storms, waves).&lt;/p&gt;&#xA;" OwnerUserId="12659" LastEditorUserId="11908" LastEditDate="2019-03-11T23:21:07.460" LastActivityDate="2019-03-11T23:21:07.460" Title="At what rate does Earth's atmosphere shed heat into space?" Tags="|geology|atmosphere|climate-change|" AnswerCount="1" CommentCount="1" ClosedDate="2019-03-14T17:47:12.730" ContentLicense="CC BY-SA 3.0" />
  <row Id="13873" PostTypeId="2" ParentId="13872" CreationDate="2018-04-12T05:15:50.057" Score="3" Body="&lt;p&gt;I don't fully get the rationale of your energy budget analogy. Nevertheless, the main question is easy to address.&#xA;The Earth's &lt;a href=&quot;https://en.wikipedia.org/wiki/Effective_temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;effective radiating temperature&lt;/a&gt; is -21°C and its emissivity approximately 0.96 (&lt;a href=&quot;https://en.wikipedia.org/wiki/Effective_temperature#Earth_Effective_Temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;). Plugging all that on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stefan–Boltzmann law&lt;/a&gt;, you get that Earth's atmosphere sends energy out to outer space at a rate of 220 $W/m^2$, totalling for the whole Earth approximately $112 \times 10^{15}$ or 112 PW (Peta Watts). Over a year that means approximately $3.5 \times 10^{24}$ J.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That should be a very good approximation, but small variations due to climate natural variability and climate change are very important to know the exact Earth's energy budget. That's why many satellites have dedicated instruments to measure this value. One good example is the &lt;a href=&quot;https://www.nasa.gov/content/goddard/noaas-dscovr-nistar-instrument-watches-earths-budget/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NISTAR radiometer&lt;/a&gt; onboard  of &lt;a href=&quot;https://en.wikipedia.org/wiki/Deep_Space_Climate_Observatory&quot; rel=&quot;nofollow noreferrer&quot;&gt;DSCOVR&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is important to know that the above figure ignores the energy reflected from the Sun. But when considering the energy budget that energy is accounted by Earth's &lt;a href=&quot;https://en.wikipedia.org/wiki/Albedo&quot; rel=&quot;nofollow noreferrer&quot;&gt;albedo&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-04-12T05:26:37.710" LastActivityDate="2018-04-12T05:26:37.710" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13874" PostTypeId="1" AcceptedAnswerId="13907" CreationDate="2018-04-12T07:48:37.470" Score="2" ViewCount="275" Body="&lt;p&gt;&lt;a href=&quot;https://twitter.com/DarylBlanks/status/973915634215145473&quot; rel=&quot;nofollow noreferrer&quot;&gt;This tweet&lt;/a&gt; by Daryl Blanks asks:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Day 1 VTMR trip @GeologyLeics -First stop Laxford bridge! gneiss with amphibolite and granitic pegmatite intrusions - can u spot all x-cutting relationships?!&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What are cross-cutting relationships in this context, and how many are there?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oIu4m.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oIu4m.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="28050" LastEditDate="2018-04-14T17:36:04.833" LastActivityDate="2018-04-14T17:36:04.833" Title="What are &quot;x-cutting relationships&quot;?" Tags="|geology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13875" PostTypeId="1" AcceptedAnswerId="14282" CreationDate="2018-04-12T12:29:35.960" Score="2" ViewCount="84" Body="&lt;p&gt;SYNOP code (see &lt;a href=&quot;http://weather.unisys.com/wxp/Appendices/Formats/SYNOP.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://weather.unisys.com/wxp/Appendices/Formats/SYNOP.html&lt;/a&gt;) has a field for describing cloud types by different levels, given as &quot;8NCCC&quot; (see link for further info, Cloud type information). And there is a program for converting SYNOP to XML, &lt;a href=&quot;http://metaf2xml.sourceforge.net/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://metaf2xml.sourceforge.net/&lt;/a&gt;, which in most cases seems to work. However, when the cloud code is &quot;80000&quot;, which IMO is correct for a cloudless sky, then the program says &quot;invalidFormat&quot;. So does anybody know if &quot;80000&quot; is correct or not?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit:&#xA;&quot;AAXX 11003 63658 32970 00905 10207 20060 38860 48492 80000 333 58002 555 10130&quot;&#xA;Real life example showing that total cloud cover in previous section is also 0. Does this mean that when &lt;code&gt;total cloud cover = 0&lt;/code&gt; is already given, then the section about cloud types is anyway meaningless?&lt;/p&gt;&#xA;" OwnerUserId="3385" LastEditorUserId="3385" LastEditDate="2018-04-12T13:37:53.687" LastActivityDate="2018-05-27T06:10:53.163" Title="Cloudless sky in synop message?" Tags="|synoptic|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13876" PostTypeId="1" AcceptedAnswerId="13901" CreationDate="2018-04-12T15:32:36.603" Score="5" ViewCount="149" Body="&lt;p&gt;This formation was found in the Capital Reef area of Southern Utah (38.2970546, -111.2979319).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There wasn't just one, but several of these small crater formations all over the area. All of them had the same basic structure: a ring of raised rock with fins, surrounding a depression that seems to be at about the same level as the surrounding rock. The rings were darker in color with lighter fins, and the depressions in the middle are lighter in color. All about 20-40 cm in diameter. The rock they are in is most likely a sandstone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anybody know what this is and how it was formed?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first image is a nearly straight down view, and the second image is an angled image to highlight the fins that ring the depression.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Keys for scale (there wasn't a banana available ;) )&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4NM2F.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4NM2F.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Xp1u0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Xp1u0.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12666" LastEditorDisplayName="user12525" LastEditDate="2019-08-30T09:09:28.093" LastActivityDate="2019-08-30T09:09:28.093" Title="Utah rock pattern identification - looks like small craters" Tags="|geology|geophysics|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13878" PostTypeId="2" ParentId="9521" CreationDate="2018-04-12T17:46:36.503" Score="11" Body="&lt;p&gt;&lt;strong&gt;The image is real, and the clouds are moving&lt;/strong&gt;, they just move slow, as clouds do.&#xA;The unnatural appearance arise because they are taken by &lt;a href=&quot;https://en.wikipedia.org/wiki/Deep_Space_Climate_Observatory&quot; rel=&quot;nofollow noreferrer&quot;&gt;DSCOVR&lt;/a&gt; at an extraordinarily large  distance, from a place called &lt;a href=&quot;https://en.wikipedia.org/wiki/Lagrangian_point&quot; rel=&quot;nofollow noreferrer&quot;&gt;L1&lt;/a&gt;, more than &lt;strong&gt;one million kilometers away!!!&lt;/strong&gt;.&#xA;The rotation of the Earth in the animation makes it difficult to distinguish the movement of the clouds, but if you just track one single area as shown in the animation below, the movements of the clouds becomes evident:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/84XnY.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/84XnY.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The zoom area shown in the right was extracted from the circled area in the left.&#xA;For the above animation I downloaded the original frames at high resolution from &lt;a href=&quot;https://svs.gsfc.nasa.gov/vis/a010000/a011900/a011971/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. The resolution was reduced so that it is smaller than the limit of SE (2MB), but you can see it at full resolution &lt;a href=&quot;https://i.imgur.com/EcuKxBB.gifv&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here you can see a closeup on the cropped section:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BaGIi.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BaGIi.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The changes and movements of the clouds are quite obvious now. Aren't they?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The overall deformation is mostly due to perspective changes as Earth's rotates, but it is clear how some clouds change, and some dissolve completely during the video, like the elongated one in the upper left corner of the cloudless patch shown in the crop. If you put attention the vanishing of that cloud can be seen in the original video.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another effect that might make the image looks weird, is the fact that the images used for the red, green and blue channels of the image are taken 30 seconds apart, and due to the displacement of the Earth and specially the Moon during that period, it creates an edge effect that is very clear in the full resolution image and might contribute to the fact that the moon seem to be pasted in the image, and the overall weirdness of the image. Here a close-up to the Moon showing very clearly the edge effect:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/h5dWJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/h5dWJ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-08-17T19:30:03.913" LastActivityDate="2018-08-17T19:30:03.913" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="13879" PostTypeId="2" ParentId="13865" CreationDate="2018-04-12T21:14:40.960" Score="3" Body="&lt;p&gt;It should also be noted that &lt;a href=&quot;http://www.euronews.com/2018/01/04/here-s-how-europe-s-storm-names-are-chosen-and-you-can-pick-one-too&quot; rel=&quot;nofollow noreferrer&quot;&gt;Europe has a history of applying names to historic storms&lt;/a&gt;... though the practice has only started to become a bit more formalized recently, driven in part by confusion between inconsistent names and notability.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/European_windstorm#Germany&quot; rel=&quot;nofollow noreferrer&quot;&gt;Media in Germany started naming storms in the 1950s, but their process has had plenty of controversy along the way... (apparently now a storm's naming rights can now be purchased by companies or citizens!?!)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Winter_storm_naming_in_the_United_Kingdom_and_Ireland&quot; rel=&quot;nofollow noreferrer&quot;&gt;UK and Ireland started naming strong extratropical cyclones&lt;/a&gt; a few years ago, &lt;a href=&quot;https://en.wikipedia.org/wiki/2017%E2%80%9318_European_windstorm_season&quot; rel=&quot;nofollow noreferrer&quot;&gt;joined by France, Spain, and Portugal this season&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As mentioned in BarocliniCplusplus's answer, many &lt;a href=&quot;https://www.americanwx.com/bb/topic/36966-twc-going-to-name-winter-storms-this-winter/&quot; rel=&quot;nofollow noreferrer&quot;&gt;amateur&lt;/a&gt; and &lt;a href=&quot;https://www.livescience.com/43378-naming-winter-storms.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;professional meteorologists&lt;/a&gt; have &lt;a href=&quot;https://www.washingtonpost.com/news/capital-weather-gang/wp/2013/10/01/weather-channel-to-name-winter-storms-for-second-year/&quot; rel=&quot;nofollow noreferrer&quot;&gt;shown&lt;/a&gt; a range of dissatisfaction with the Weather Channel naming these systems, for reasons including:  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;It suggests the Weather Channel believes presumptuously that they are worthy of claiming to be some sort of larger body of official authority&lt;/li&gt;&#xA;&lt;li&gt;The application of the names seems quite arbitrary, mainly based on impacts in the southern and eastern US, rather than the mostly objective basis for tropical cyclone naming.&lt;/li&gt;&#xA;&lt;li&gt;While winter storms indeed can be rather life-changing and significant events, it still waters down the usage of names as a whole... as many people note, should we also start naming wildfires, floods, squall lines, and everyday thunderstorms?&lt;/li&gt;&#xA;&lt;li&gt;As can be common in commercial media, The Weather Channel does have a history of hyping and over-dramatizing storms for eyeballs (&lt;a href=&quot;https://www.wired.com/2015/01/the-weather-service-that-cried-wolf/&quot; rel=&quot;nofollow noreferrer&quot;&gt;see the example in this story&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;But for what it's worth, whether it's the extra attention garnered or the belief it's helping in disseminating storm information, 2017-18 marks the sixth year that The Weather Channel has named storms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(See also: &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_historic_tropical_cyclone_names&quot; rel=&quot;nofollow noreferrer&quot;&gt;naming tropical cyclones&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2018-04-12T21:14:40.960" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13880" PostTypeId="2" ParentId="12053" CreationDate="2018-04-12T23:07:18.720" Score="4" Body="&lt;p&gt;There are a number of factors that went/are going into the population explosion, food is only one vaccination and antibiotics are a big factor as well.  within food fertilizer is again only one of many factors. Better crop strains, mechanized and better farming techniques, soil science, pesticides, refrigeration, and a dozen other factors contributed.  Keep in mind artificial fertilizers get less important as you go back in time as well so calling it the detonator is incorrect and misleading. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now when considering crop rotation, crop rotation has pros and cons, there are several nutrients plants need and rotation only helps with some of them, and it relies on having compatible crops to rotate which not every crop or environment has.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Keep in mind the piece wikipedia is quoting is not a peer reviewed paper but an &lt;a href=&quot;http://vaclavsmil.com/wp-content/uploads/docs/smil-article-1999-nature7.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;essay&lt;/a&gt; in nature, which explains it is referring to several modern countries that fertilize almost exclusively with artificial fertilizers. It is not claiming they cannot use other fertilizers.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2018-04-13T13:23:04.663" LastActivityDate="2018-04-13T13:23:04.663" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13881" PostTypeId="2" ParentId="12053" CreationDate="2018-04-13T00:52:55.263" Score="2" Body="&lt;p&gt;There are several aspects to be considered in this apparent difference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, your quote from Wikipedia describes the change in productivity but does not account for other factors that have lead to productivity increase such as changed farming practices (larger, more sophisticated farm equipment, improved use of weather and soil data, etc.) changes to crop species and cultivars - especially the increase in use of hybrids, and increased irrigation. Thus, the contribution of nitrogen fertilizers is only one factor, although an important one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly, you can compensate for the lack of chemical nitrogen fertilizer through a number of methods, but that doesn't negate the changes due to the widespread adoption of nitrogen fertilizers. You can use organic fertilizers to increase production but there may be limits on the ability to do so on the scale of conventional agriculture. You may be able to use more labor-intensive techniques on a small scale that could not be adopted on the scale of modern agriculture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally there are cost considerations. It may not always be financially feasible to increase productivity through organic farming methods. Or at least society may not be willing to pay the price&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2018-04-13T00:52:55.263" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13882" PostTypeId="1" AcceptedAnswerId="13906" CreationDate="2018-04-13T00:57:22.830" Score="3" ViewCount="2035" Body="&lt;p&gt;I'll preface this with the truth and hope it doesn't disqualify the question but rather give context: after reading Journey to the Center of the Earth by Jules Verne, I am amazed at the prospect of venturing into volcanic conduits to explore the interior of the Earth. &lt;strong&gt;How deep do lava conduits go, why don't they go deeper, and what kinds of formations or environments exist at their terminus?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not new to Earth science but am pretty new to in-depth geology (pun intended) and volcanology. From what I can tell, the type of &lt;a href=&quot;https://en.wikipedia.org/wiki/Lava_cave&quot; rel=&quot;nofollow noreferrer&quot;&gt;lava cave&lt;/a&gt; which goes the deepest is referred to as a &lt;a href=&quot;https://en.wikipedia.org/wiki/Lava_tube&quot; rel=&quot;nofollow noreferrer&quot;&gt;lava tube&lt;/a&gt;. Apparently these tubes can be fairly long (e.g. a tube from Mauna Loa goes 50km before terminating[?] at the ocean!) but not very deep (Wikipedia on lava tubes lists a mere 15m!) Why do these tubes not go far deeper?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The deepest conduit from surface to inner Earth is apparently the &lt;a href=&quot;https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kola Superdeep Borehole&lt;/a&gt; which terminates at ~12km deep upon reaching higher-than-expected temperatures. I think of magma - liquefied hot rock erupting out of volcanoes - as coming from even deeper than that depth. Therefore, why doesn't lava tubes or other volcanic conduit continue to such deep depths? Do they, but it is too difficult to explore? Do they during eruptions, but soon after cool and fill with solidified rock or eventually collapse and thereby fill with rock?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As noted I'm new but interested to the subject, so any info to help me understand the processes and environment involved in this interface between inner Earth and the surface would be much appreciated.&lt;/p&gt;&#xA;" OwnerUserId="4789" LastEditorUserId="4789" LastEditDate="2018-04-13T14:35:57.240" LastActivityDate="2018-04-14T06:50:58.620" Title="How vertically deep do lava conduits go?" Tags="|geology|volcanology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13883" PostTypeId="1" CreationDate="2018-04-13T01:22:14.470" Score="2" ViewCount="105" Body="&lt;p&gt;I'm curious to learn more about the research and thought that went into calculating the heat index. In particular I want to understand how Steadman or Rothfusz managed to fit a model (in terms of relative humidity and temperature) on data with variables related to human physiology.&lt;/p&gt;&#xA;" OwnerUserId="12673" LastEditorUserId="12673" LastEditDate="2018-04-13T01:40:28.603" LastActivityDate="2018-04-13T01:40:28.603" Title="Where can I find the original scientific articles on Heat index (published by either Larry P. Rothfusz or Steadman)?" Tags="|climate-models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13884" PostTypeId="2" ParentId="13883" CreationDate="2018-04-13T01:39:51.110" Score="4" Body="&lt;p&gt;After having a look at the references of a few papers about heat index (like &lt;a href=&quot;https://pdfs.semanticscholar.org/9de1/82387865ce71fbe09a0af70c0c8f641b74d8.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one&lt;/a&gt;). It looks like the original publications you are looking for are&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;The Heat Index &quot;Equation&quot; (or, More Than You Ever Wanted to Know About Heat Index)&lt;/strong&gt; by Lans P. Rothfusz available &lt;a href=&quot;https://www.weather.gov/media/bgm/ta_htindx.PDF&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, and&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;The Assessment of Sultriness. Part I: A Temperature-Humidity Index Based on Human Physiology and Clothing Science&lt;/strong&gt;, by R. G. Steadman available &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/1520-0450%281979%29018%3C0861%3ATAOSPI%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;As a general suggestion, looking at the references in related papers is always a great way to find the original research articles on any topic.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-04-13T01:39:51.110" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13886" PostTypeId="1" CreationDate="2018-04-13T11:51:34.430" Score="1" ViewCount="36" Body="&lt;p&gt;Here is the chart:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/lSTmN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lSTmN.jpg&quot; alt=&quot;Chart&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My questions are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Is the atmosphere in equilibrium over this record?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;how would I determine what the maximum and minimum values for each&#xA;record is (approximation).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Is there a correlation between records for CO2, CH4 and temperature?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Are today's values within the normal range of variability for this record?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="12218" LastActivityDate="2018-04-13T11:51:34.430" Title="How to analyze this data showing atomospheric CO2, CH4 and tempertures obtain from an ice sample?" Tags="|atmosphere|climate-change|atmospheric-chemistry|co2|" AnswerCount="0" CommentCount="12" ContentLicense="CC BY-SA 3.0" />
  <row Id="13887" PostTypeId="1" CreationDate="2018-04-13T12:05:03.293" Score="2" ViewCount="200" Body="&lt;p&gt;I have data from 2 &lt;a href=&quot;https://en.wikipedia.org/wiki/Pyranometer&quot; rel=&quot;nofollow noreferrer&quot;&gt;pyranometers&lt;/a&gt;, one in the horizontal plane and one in a tilted plane. The relevance of the tilting relates to their useage in solar-power plants whereby the tilt is in the same plane as the solar generators.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can apply simple trigonometry to convert the horizontal data to a theoretical value in the tilted plane. On some days we notice a very good correlation between the measured data in the tilted plane compred to the theoretical value calculated from measured data in the horizontal plane. On other days the correlation is not so clear and the degree of correlation can differ greatly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Hypothesis :&lt;/strong&gt; I imagine that the difference in correlation that we notice is due to the effects of cloud cover.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question :&lt;/strong&gt; Is there an established method to calculate this cloud cover from our two datasets ?&lt;/p&gt;&#xA;" OwnerUserId="12678" LastEditorUserId="11908" LastEditDate="2018-04-13T17:52:02.130" LastActivityDate="2018-04-13T18:15:46.230" Title="Calculating a cloud cover index based on comparison of horizontal and tilted irradiance from pyranometers" Tags="|meteorology|clouds|solar-terrestrial-physics|light|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13888" PostTypeId="1" AcceptedAnswerId="13890" CreationDate="2018-04-13T12:05:44.270" Score="3" ViewCount="801" Body="&lt;p&gt;My question is quite simple, but I can't seem to find any answer to it: how do we define the limit of the object &quot;Earth&quot;? More specifically, can we consider the atmosphere a part of it? Or even the oceans, for that matter? I was going for a no at first glance, but that would mean that you are actually leaving the Earth when you fly on a plane. That feels weird. How do scientists define the limit of the Earth?&lt;/p&gt;&#xA;" OwnerUserId="12679" LastEditorUserId="111" LastEditDate="2018-04-14T10:20:12.113" LastActivityDate="2018-04-14T12:12:31.177" Title="Is the atmosphere a part of Earth?" Tags="|terminology|planetology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13889" PostTypeId="1" CreationDate="2018-04-13T12:08:30.907" Score="0" ViewCount="51" Body="&lt;p&gt;Graph I am analyzing:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Yu7Vl.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Yu7Vl.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I am trying to figure out from the graph is:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;What is the range for CO&lt;sub&gt;2&lt;/sub&gt; over the record (approximation)&lt;/li&gt;&#xA;&lt;li&gt;What are the major forcings for the overall trend in this record&lt;/li&gt;&#xA;&lt;li&gt;What is the range for CO&lt;sub&gt;2&lt;/sub&gt; over a typical annual cycle (approximation)&lt;/li&gt;&#xA;&lt;li&gt;What are at least wo key properties of the physical geography of the Earth that contribute to these cycles?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="12218" LastEditorUserId="725" LastEditDate="2018-04-14T06:27:16.630" LastActivityDate="2018-04-14T06:27:16.630" Title="How does one analyze this graph on atmospheric C02 data obtained from the Mauna Loa observatory?" Tags="|climate-change|homework|co2|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13890" PostTypeId="2" ParentId="13888" CreationDate="2018-04-13T12:29:37.453" Score="5" Body="&lt;p&gt;It's all in how one chooses to define it M.Connor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Often in physical science courses, we &lt;a href=&quot;https://www.eartheclipse.com/geography/4-different-spheres-of-earth.html&quot; rel=&quot;noreferrer&quot;&gt;define the Earth system&lt;/a&gt; as the lithosphere (rocks), atmosphere (air), biosphere (life), and hydrosphere (water) [also sometimes separately defining a 5th aspect, the cryosphere, which is ice]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the end, we often just think of the Earth as everything confined by its gravity (not including in orbit) as that's everything still controlled by the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But in a very true sense, you're still leaving the Earth when you take off on a plane.&lt;br&gt;&#xA;Just you're still in a state/region of the Earth's system where what goes up must come down.  So you won't be gone long!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2018-04-13T12:29:37.453" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13891" PostTypeId="1" CreationDate="2018-04-13T14:57:54.153" Score="4" ViewCount="1416" Body="&lt;p&gt;Would the dynamic between soil nitrogen and plant growth be a positive or negative feedback loop&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think it is a negative feedback loop because as soil nitrogen increases then plant growth increases, and as plant growth increases, soil nitrogen decreases, is this correct? Therefore, since $+ × - = -$, it's a negative feedback loop.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, what about the feedback loop between temperature and soil organic matter? As temperature increases so does soil organic matter, as soil organic matter increases so does the release of CO&lt;sub&gt;2&lt;/sub&gt; thus causing more warming. A positive feedback loop.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this reasoning correct?&lt;/p&gt;&#xA;" OwnerUserId="12218" LastEditorUserId="28050" LastEditDate="2018-04-14T17:42:49.317" LastActivityDate="2021-12-19T06:05:50.553" Title="Feedback loops between soil chemistry and plant growth" Tags="|atmosphere|climate|nitrogen|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13893" PostTypeId="2" ParentId="13887" CreationDate="2018-04-13T17:41:03.093" Score="2" Body="&lt;p&gt;Not being an expert in the subject, I agree with your hypothesis. But, I think that what you are measuring with the difference in the readings is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Anisotropy&quot; rel=&quot;nofollow noreferrer&quot;&gt;anisotropy&lt;/a&gt; of the illumination. In very cloudy skies, the amount of light from all directions in the sky is the same (that's why you can't tell where is the Sun). In a extreme case, like the condition refereed as &lt;em&gt;whiteout&lt;/em&gt; (dense fog over snow) a pyranometer on any direction would measure the same value.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I don't think that can be used to calculate cloud cover in the common sense, as the anisotropy will be very high even if there is a small gap in the clouds that let the Sun light through, so your conversion into cloud cover would only work when the cloud cover is homogeneous, and would fail when it is patchy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would think that you have better chances to estimate clod cover if you have one pyranometer shielded from direct sunlight , so you can measure how much energy is coming from the sky. However, you would only know the cloud cover in that area, and still with many posible source of error.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Measuring cloud cover is a difficult problem. Naked‐eye observation of sky cloud cover has widely resisted automation. Some successful approaches use analysis of images like in &lt;a href=&quot;https://en.wikipedia.org/wiki/Whole_sky_camera&quot; rel=&quot;nofollow noreferrer&quot;&gt;Whole sky cameras&lt;/a&gt; or more sophisticated &lt;a href=&quot;https://www.arm.gov/capabilities/instruments/wsi&quot; rel=&quot;nofollow noreferrer&quot;&gt;whole sky imagers&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, there are methods developed to estimate cloud cover based on standard AWS data. Like APCADA, that uses longwave downward radiation, temperature, and relative humidity measurements. It is described in the paper &quot;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2003JD004182&quot; rel=&quot;nofollow noreferrer&quot;&gt;Automatic cloud amount detection by surface longwave downward radiation measurements&lt;/a&gt;&quot;, that reports that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;APCADA estimates. Results show that about 86% of all cases agree&#xA;  within ±1‐octa cloud amount difference for sites with moderate&#xA;  climate, 82% for sites with arctic climate, and 78% for the site with&#xA;  tropical climate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I would think that for the direction technology have taken, the most affordable options will go in the direction of having a camera taking pictures of the sky (in infrared if you can), and having and algorithm to analyze it and evaluate cloud cover. I found &lt;a href=&quot;https://www.researchgate.net/publication/257449257_Ground-based_measurements_of_local_cloud_cover&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt; that talks about that. It looks like the Red/Blue ratio is a good indicator to classify an image pixel as cloud or cloudless. &lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-04-13T18:15:46.230" LastActivityDate="2018-04-13T18:15:46.230" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13894" PostTypeId="2" ParentId="13891" CreationDate="2018-04-13T20:20:02.993" Score="1" Body="&lt;p&gt;You're on the right track, though the positive and negative aspect of feedback loops is more about dynamics of the overall system rather than just the increase or decrease of components in the feedback loop. This website offers a straight forward explanation of positive vs. negative feedback loops &lt;a href=&quot;https://serc.carleton.edu/introgeo/models/loops.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://serc.carleton.edu/introgeo/models/loops.html&lt;/a&gt; :&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Feedback Loops can enhance or buffer changes that occur in a system.&lt;/p&gt;&#xA;  &#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;&lt;strong&gt;Positive feedback loops&lt;/strong&gt; enhance or amplify changes; this tends to move a system away from its equilibrium state and make it more&#xA;  unstable.&lt;/li&gt;&#xA;  &lt;li&gt;&lt;strong&gt;Negative feedbacks&lt;/strong&gt; tend to dampen or buffer changes; this tends to hold a system to some equilibrium state making it more stable.&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In your second example, the feedback loop between temperature and soil organic matter leads to amplified changes in the system, making it more unstable. You're correct in identifying this as a positive feedback loop.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the first example about plant available nitrogen and plant growth, there is a feedback loop there but is it positive or negative? You noted that the effect of increased plant growth would reduce available nitrogen. That isn't necessary the case, but even if it was, reduced nitrogen itself could actually be a positive feedback loop because it would lead the system out of equilibrium and into an unstable state (with the plants present no longer able to sustain themselves). However, in an undisturbed ecosystem I'd expect this to actually &lt;em&gt;increase&lt;/em&gt; available nitrogen and also &lt;em&gt;increase stability&lt;/em&gt; of the system over time, making this a negative feedback loop. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The relationship between soil nutrients and plants can be complex and vary between plants (e.g. leguminous plants would certainly create a negative feedback loop, enhancing the stability of the system they are thriving in). In general plants left to their own succession would increase organic matter which serves as a nutrient reservoir, further enhancing nutrient availability. In our more controlled agricultural systems, you can see this effect applied in &lt;a href=&quot;https://en.wikipedia.org/wiki/Crop_rotation&quot; rel=&quot;nofollow noreferrer&quot;&gt;crop rotation&lt;/a&gt; and &lt;a href=&quot;https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=2396&amp;amp;context=usdaarsfacpub&quot; rel=&quot;nofollow noreferrer&quot;&gt;allowing fields to go fallow&lt;/a&gt; as a means to increase available nutrients among other potential benefits. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that the nature of a feedback loop also depends on how the system's boundaries are defined. This is especially true looking at industrial agriculture and other systems that rely heavily on external inputs or otherwise have far-removed externalities.&lt;/p&gt;&#xA;" OwnerUserId="4789" LastActivityDate="2018-04-13T20:20:02.993" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13895" PostTypeId="1" CreationDate="2018-04-13T20:46:35.410" Score="1" ViewCount="29" Body="&lt;p&gt;Is it possible to use remote sensing to determine Hydrothermal alteration zones without resorting to collecting samples from the Area of study?&lt;/p&gt;&#xA;" OwnerUserId="12684" LastActivityDate="2018-04-13T20:46:35.410" Title="Detecting the hydrothermal alteration zones?" Tags="|geology|mineralogy|remote-sensing|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13896" PostTypeId="1" CreationDate="2018-04-13T20:59:12.783" Score="0" ViewCount="61" Body="&lt;p&gt;How do you get a submarine to rise from the bottom of the ocean to the surface again? Do you press a button? Flip a switch? Use a lever? How do you initiate the surfacing process?&lt;/p&gt;&#xA;" OwnerUserId="12685" LastActivityDate="2023-01-22T15:41:45.217" Title="How would one get a submarine to rise?" Tags="|water|" AnswerCount="1" CommentCount="2" ClosedDate="2018-04-14T09:12:27.110" ContentLicense="CC BY-SA 3.0" />
  <row Id="13897" PostTypeId="2" ParentId="13896" CreationDate="2018-04-13T23:27:40.057" Score="1" Body="&lt;p&gt;Interesting question but more of an engineering one. The basic physics is that a submarine modifies its &lt;a href=&quot;https://en.wikipedia.org/wiki/Buoyancy&quot; rel=&quot;nofollow noreferrer&quot;&gt;buoyancy&lt;/a&gt; by filling various chambers (dedicated for this purpose) with water or pumping the water out and filling the chambers with air. Understanding buoyancy is important: basically, if something weighs less than the water it displaces, it floats; if something weighs more than the water it displaces, it sinks.&lt;/p&gt;&#xA;&lt;p&gt;As more water is allowed to enter the submarine's chambers through the opening of valves, the submarine becomes heavier (or another way to look at it is, the submarine is decreasing its displacement of water by allowing the water to fill its volume) and therefore its buoyancy decreases and it can be caused to sink. When air is pumped into the chambers and water is pumped out and then sealed out of the vessel, the submarine becomes lighter and has a larger displacement, so its buoyancy increases and it rises toward the surface.&lt;/p&gt;&#xA;&lt;p&gt;Pressure differentials play a big role in all this. Getting water back into the chambers, getting water out of the chambers and filling them with air, maintaining healthy pressure for the submarine's compartments that house humans - all this involves a careful calculation of pressures in different parts of the system and how we can manage and change those pressures to get the submarine to function as desired.&lt;/p&gt;&#xA;" OwnerUserId="4789" LastEditorDisplayName="user28336" LastEditDate="2023-01-22T15:41:45.217" LastActivityDate="2023-01-22T15:41:45.217" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="13898" PostTypeId="1" CreationDate="2018-04-13T23:44:23.510" Score="7" ViewCount="340" Body="&lt;p&gt;I was surfing around on Google Maps and found dozens of clearings amid a sea of vegetation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are they? Some look like rocks, others can't be made out due to the image resolution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is one &lt;a href=&quot;https://www.google.com/maps/@-5.0959588,-66.4151768,3996m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;specific clearing&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cLUnq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cLUnq.png&quot; alt=&quot;one example of a clearing in question&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.com/maps/@-4.9760484,-66.430585,31974m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dozens of clearings (zoom in on dots of lighter color in forest)&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12687" LastEditorUserId="6298" LastEditDate="2022-02-06T17:25:22.637" LastActivityDate="2022-02-15T22:20:00.803" Title="What are these clearings in Amazon rainforest?" Tags="|mapping|forest|amazon|landscape|satellite-oddities|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13899" PostTypeId="1" CreationDate="2018-04-14T00:57:51.447" Score="1" ViewCount="126" Body="&lt;p&gt;There have been reports about the Gulf Stream weakening. Everything I have read about this concentrates on the (possibly substantial) cooling this would cause in Europe. &#xA;If this weakening occurs, presumably there will be much less heat transported away from the southern end of the Gulf Stream causing warming in the Atlantic and Caribbean. Has any modelling been done to indicate what the consequences of this are likely to be?&lt;/p&gt;&#xA;" OwnerUserId="12688" LastActivityDate="2018-04-14T00:57:51.447" Title="Gulf stream weakening affects on both ends of the system - Europe and Carribean" Tags="|climate-change|oceanography|climate-models|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13901" PostTypeId="2" ParentId="13876" CreationDate="2018-04-14T01:16:42.897" Score="3" Body="&lt;p&gt;Relief features made by microbial mats which were gelatinous. The ridges and fins are thought to be caused by small currents that flowed through the umbrella like bodies of these ancient bacteria.&lt;/p&gt;&#xA;" OwnerUserId="12495" LastActivityDate="2018-04-14T01:16:42.897" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13902" PostTypeId="2" ParentId="13898" CreationDate="2018-04-14T02:33:47.193" Score="2" Body="&lt;p&gt;Hard to say. Some could be clearings for log landings, some for small villages or outposts used by the military or others, some cleared due to natural disturbance in the area (e.g. fire from lightening strikes) though I'd expect the latter to have sparse canopy and not be totally clear.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many of these patches don't have signs of good access routes (other than by air or through thick vegetation). No doubt there can be smaller trails and rivers under the canopy, but we don't see any substantial routes with canopy cleared overhead. Therefore, logging and mining seems less likely, though both occur in the region. Smaller scale operations, like a clearing for more sun-loving plants by a local human population, could account for some of these though.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;On the village or outpost possibility&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Consider these clearings:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.google.com/maps/@-4.8351321,-66.3508833,2000m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Two relatively nearby clearings, one with what appears to be grainy rocks but could be &lt;em&gt;thatched roofs of a village&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.google.com/maps/@-4.8189234,-66.3239361,1998m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Another nearby clearing that appears to have a significant amount of its soil covered in a darker shaded texture, again perhaps thatched roofs&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.google.com/maps/@-5.0938031,-66.4013186,2000m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;And another clearing, partially open and partially with this same darker texture to it in a shape that could certainly be a spread of small buildings in a community&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I &lt;a href=&quot;https://www.ecosia.org/images?q=tribo%20indigena%20na%20amazonia%20casa&quot; rel=&quot;nofollow noreferrer&quot;&gt;searched for on-the-ground views of potential villages&lt;/a&gt; and found a few that could match the view from above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a large communal structure in a clearing which could match some of the textures we see. Some indigenous groups of the Amazon live in large structures like this as a community, and some just use large structures like this as ceremonial communal spaces.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/LU19R.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LU19R.jpg&quot; alt=&quot;large communal structure that could fill up a clearing&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a set of buildings in a village clearing. Note how close the forest canopy comes to the buildings. Given how thick the forest is, it's probably not easy to manage, but that could be all the more reason to get to bare ground in these village clearings.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/areSS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/areSS.jpg&quot; alt=&quot;set of buildings in a village clearing&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a pretty amazing example of small scale clearings and manipulation of the forest landscape by indigenous communities. While we're not seeing this from a satellite, it points out how the lack of texture nearby and between these clearings doesn't necessarily mean there's no trails or human presence. It appears these structures are surrounded by unusual tree canopies - perhaps banana or another agroforest crop - which could be cultivated from nearby shelters. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/NBQDv.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NBQDv.jpg&quot; alt=&quot;narrow row of small structures nearby forest&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In conclusion, a likely possibility is that these clearings are signs of relatively-isolated small-scale villages or outposts.&lt;/p&gt;&#xA;" OwnerUserId="4789" LastEditorUserId="4789" LastEditDate="2018-06-14T13:39:41.687" LastActivityDate="2018-06-14T13:39:41.687" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="13903" PostTypeId="1" CreationDate="2018-04-14T04:35:44.577" Score="2" ViewCount="322" Body="&lt;p&gt;As the Earth formed, it went through cycles of essentially hotter and colder periods. Extremely volcanic times and ice ages, in feedback loops contributing to one another. CO&lt;sub&gt;2&lt;/sub&gt; swinging from high to low back and forth, all the while islands and landforms are evolving. In some ways it's like a ripple effect moving through the Earth as it came to be the shape it is today, still with an evolving climate and form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How many extreme temperature and activity cycles has the Earth (or at least the surface of it) gone through since its formation?&lt;/strong&gt; I understand there might be some uncertainty since this is over the scale of hundreds of millions of years. If the question can be answered clearer within a limited geological time period please do apply that boundary and answer for a more recent time period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd also be interested to learn about any kinds of measurements or cutting edge topics or research questions that would help us learn about these cycles in the past.&lt;/p&gt;&#xA;" OwnerUserId="4789" LastEditorUserId="725" LastEditDate="2018-04-14T06:20:09.457" LastActivityDate="2021-01-31T08:27:37.903" Title="How many extreme shifts in climate has Earth gone through in its existence?" Tags="|geology|volcanology|paleoclimatology|glaciology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13904" PostTypeId="2" ParentId="13903" CreationDate="2018-04-14T04:42:53.533" Score="1" Body="&lt;p&gt;As I finished writing this question I did find one answer. I'll ask anyway and see if anyone has more info to contribute.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;https://en.wikipedia.org/wiki/Ice_age#Origin_of_ice_age_theory&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Wikipedia page on Ice Ages&lt;/a&gt;, there's this Timeline of life including a list of ice ages on left side.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/y2O8q.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/y2O8q.png&quot; alt=&quot;Timeline of life including list of ice ages on left side&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Based on this, there were 7 ice ages in the past 4.5 billion years (apx age of the Earth). Were there also 7 major periods of high volcanic activity? &lt;/p&gt;&#xA;" OwnerUserId="4789" LastActivityDate="2018-04-14T04:42:53.533" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13906" PostTypeId="2" ParentId="13882" CreationDate="2018-04-14T06:50:58.620" Score="3" Body="&lt;p&gt;As mentioned in the comments, lave caves and tubes are surface features. You get a lava tube when there's a lava flow and the external part in contact with air (or water) cools down and solidifies while the interior is still flowing. &lt;a href=&quot;https://www.nationalgeographic.com/magazine/2017/06/lava-tubes-hawaii-caves/&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Geographic made an excellent feature on it, all with diagrams and photos and stuff.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Why do these tubes not go far deeper?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Because lavas are liquid, and they flow downwards. If there's a hole that goes deep, the lava will fill it. It's possible to explosively eject lava out of a hole (as commonly happens), but these are violent events that will cause the collapse of the conduits, forming &lt;a href=&quot;http://www.largeigneousprovinces.org/sites/default/files/2012Jun-fig-10.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;breccia pipes&lt;/a&gt;, with &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Mount_Mazama_eruption_timeline.PNG#/media/File:Mount_Mazama_eruption_timeline.PNG&quot; rel=&quot;nofollow noreferrer&quot;&gt;collapsed calderas&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;I think of magma - liquefied hot rock erupting out of volcanoes - as coming from even deeper than that depth&lt;/p&gt;&#xA;&lt;p&gt;...terminating at the threshold of the asthenosphere?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Let me clear a common misconception here: &lt;strong&gt;there is no magma ocean in the interior of the Earth.&lt;/strong&gt; There is no large reservoir of magma in the deep earth, and volcanoes are not just holes through which this (non existent) magma is coming out. Both the crust and the mantle are essentially solid rock. The asthenosphere is solid rock.&lt;/p&gt;&#xA;&lt;p&gt;Melting is an uncommon occurrence in the Earth's crust and mantle. It needs exceptional circumstances to happen, which mostly happen above subduction zones (i.e. the Pacific Ring of Fire) or above hotspots (East Africa, Hawaii, Yellowstone). The erupting magma can come from anywhere that's as shallow as less than a kilometre below the surface (which can be above sealevel if you're on a high volcano) to several tens of kilometres. Very rarely these magmas come directly from asthenospheric depths. These magma chambers can have complex plumbing systems beneath them and all sorts of morphologies of feeders.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-04-14T06:50:58.620" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13907" PostTypeId="2" ParentId="13874" CreationDate="2018-04-14T07:02:24.650" Score="4" Body="&lt;p&gt;Cross cutting relationships.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EJS8H.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EJS8H.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a very rough sketch. You had the black stuff, which was then cross-cut by the red intrusion (grey in the original photo), and finally intruded by the blue intrusion (pink the in the original photo).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Law_of_superposition&quot; rel=&quot;nofollow noreferrer&quot;&gt;law of superposition&lt;/a&gt;. For more fun follow &lt;a href=&quot;https://twitter.com/hashtag/SuperpositionPuzzle&quot; rel=&quot;nofollow noreferrer&quot;&gt;#SuperpositionPuzzle&lt;/a&gt; on Twitter!&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-04-14T07:02:24.650" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13908" PostTypeId="2" ParentId="13888" CreationDate="2018-04-14T12:12:31.177" Score="2" Body="&lt;p&gt;Yes, the atmosphere is part of the Earth and as others here have stated the atmosphere thins (decreases in density) with height.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The aviation and outer space communities use the &lt;a href=&quot;https://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_line&quot; rel=&quot;nofollow noreferrer&quot;&gt;Karman Line&lt;/a&gt; as the boundary between the Earth's atmosphere and outer space. This line is 100 km above sea level. &lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-04-14T12:12:31.177" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13910" PostTypeId="2" ParentId="5204" CreationDate="2018-04-14T23:06:17.267" Score="-3" Body="&lt;p&gt;It may solve the heat problem but unlikely to solve the flood problem, and might create the cold problem in the North Atlantic.&lt;/p&gt;&#xA;" OwnerUserId="3288" LastActivityDate="2018-04-14T23:06:17.267" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13912" PostTypeId="1" AcceptedAnswerId="13925" CreationDate="2018-04-15T07:34:29.137" Score="7" ViewCount="1134" Body="&lt;p&gt;The BBC News article &lt;a href=&quot;http://www.bbc.com/news/science-environment-43701375&quot; rel=&quot;noreferrer&quot;&gt;Isolated lakes found beneath Canadian ice sheet&lt;/a&gt; links to the &lt;em&gt;open access&lt;/em&gt; Science Advances article &lt;a href=&quot;http://advances.sciencemag.org/content/4/4/eaar4353.full&quot; rel=&quot;noreferrer&quot;&gt;Discovery of a hypersaline subglacial lake complex beneath Devon Ice Cap, Canadian Arctic&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The discovery is based on radar &quot;soundings&quot; of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Devon_Ice_Cap&quot; rel=&quot;noreferrer&quot;&gt;Devon Ice Cap&lt;/a&gt; in Nunavut, Canada.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An earlier question &lt;a href=&quot;https://earthscience.stackexchange.com/q/12075/6031&quot;&gt;What is likely to have happened with these newly discovered antarctic volcanos below the ice?&lt;/a&gt; shows sub-surface radar measurements of antarctic ice, in this case to a depth of 1.5 kilometers, and therefore with a total path length of 3 kilometers in ice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The water molecule is strongly polar and interacts with microwave radiation by absorbing and thermalizing it. This effect is obvious in microwave ovens. Microwave ovens can be used to &quot;defrost&quot; frozen food even a few centimeters thick, using reduced power and longer time. This is necessary because frozen water molecules have a lower absorption than those in unfrozen areas, but they are still quite absorbing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Radar measurements travel through kilometers in ice round trip, substantially larger than the thickness of a slab of frozen peas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How is ice-penetrating radar able to work through such long path lengths of ice? Is there a special frequency thats used, or other tricks allowing for extremely weak reflections after bulk attenuation to be detected and measured?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="11908" LastEditDate="2019-03-13T05:09:41.707" LastActivityDate="2019-03-13T05:09:41.707" Title="How does ice-penetrating radar &quot;see&quot; through kilometers of ice without being absorbed?" Tags="|measurements|remote-sensing|glaciology|ice-sheets|radar|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 3.0" />
  <row Id="13913" PostTypeId="1" CreationDate="2018-04-15T08:34:53.313" Score="1" ViewCount="84" Body="&lt;p&gt;The BBC News article &lt;a href=&quot;http://www.bbc.com/news/science-environment-43701375&quot; rel=&quot;nofollow noreferrer&quot;&gt;Isolated lakes found beneath Canadian ice sheet&lt;/a&gt; links to the &lt;em&gt;open access&lt;/em&gt; Science Advances article &lt;a href=&quot;http://advances.sciencemag.org/content/4/4/eaar4353.full&quot; rel=&quot;nofollow noreferrer&quot;&gt;Discovery of a hypersaline subglacial lake complex beneath Devon Ice Cap, Canadian Arctic&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The discovery is based on radar &quot;soundings&quot; of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Devon_Ice_Cap&quot; rel=&quot;nofollow noreferrer&quot;&gt;Devon Ice Cap&lt;/a&gt; in Nunavut, Canada.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm having trouble understanding the nature of the evidence for liquid water as stated in the article. I understand that there will be a relatively strong reflection at an interface where the dielectric constant changes, and that this is expressed in dB in some of the plots, but I don't understand the blue &quot;blobs&quot; or the axis label &lt;code&gt;Spec. content&lt;/code&gt; shown.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've cropped some of the plots and rearranged them below to help highlight the &quot;blue blobs&quot; below. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also it looks like the potential lakes are associated with dips in the underlying bedrock contour, but I can't tell if the lakes are sitting on top of the bedrock, or at an intermediate elevation above it with ice both above and below them, and I don't understand at all what the axis label &lt;code&gt;Hydrolic head (m)&lt;/code&gt; in other plots means. And why does the top surface of the ice look relatively flat in the radar images, but rise and fall hundreds of meters in the &lt;code&gt;ice surface and bed&lt;/code&gt; plots? Did the plane fly at a fixed distance with respect to the top ice surface rather than a fixed elevation?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7GUor.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7GUor.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; Figure 1 from &lt;a href=&quot;http://advances.sciencemag.org/content/4/4/eaar4353.full&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/X31zZ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/X31zZ.jpg&quot; alt=&quot;Fig. 1 of hypersaline subglacial lake complex Devon Ice Cap&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="11908" LastEditDate="2019-03-13T05:13:27.573" LastActivityDate="2019-03-13T05:13:27.573" Title="Help understanding radar data in subglacial lake complex beneath Devon Ice Cap" Tags="|measurements|glaciology|ice-sheets|radar|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13917" PostTypeId="1" CreationDate="2018-04-15T18:16:15.190" Score="7" ViewCount="235" Body="&lt;p&gt;I'm a meteorologist with little experience in hydrology. I'm studying my land with the rainwater flow patterns during heavy rain events and looking to manage the erosion, flash flooding, and ponding on my property. Thankfully it backs up to natural wetlands. The main issue is that the ditch in front of our house overflows faster than it removes water downstream. Our neighbors frequently have to place sandbags at the front of their driveway to keep their garage from flooding. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not sure where to go next. Any thoughts on where to look for more information?&lt;/p&gt;&#xA;" OwnerUserId="12692" LastActivityDate="2018-04-15T20:40:43.723" Title="Who would know how to manage rainwater erosion on a sloped property?" Tags="|meteorology|hydrology|erosion|flooding|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 3.0" />
  <row Id="13918" PostTypeId="1" AcceptedAnswerId="16265" CreationDate="2018-04-15T20:32:48.177" Score="13" ViewCount="1460" Body="&lt;p&gt;How big does a body of water need to have a sea breeze? Is there a chart on sea breezes wind speed that include lakes?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could a circular lake create enough sea breeze to create a wind vortex in the center of the lake?&#xA;&lt;a href=&quot;https://worldbuilding.stackexchange.com/questions/108896/could-a-city-be-built-out-of-balloons&quot;&gt;https://worldbuilding.stackexchange.com/questions/108896/could-a-city-be-built-out-of-balloons&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UhNDj.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UhNDj.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/QOB8h.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QOB8h.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2019-02-17T19:05:23.373" LastActivityDate="2019-02-17T19:05:23.373" Title="How big does a lake have to be to have its own Sea Breeze?" Tags="|atmosphere|wind|geography|convection|mesoscale-meteorology|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="13919" PostTypeId="2" ParentId="13917" CreationDate="2018-04-15T20:40:43.723" Score="8" Body="&lt;p&gt;&lt;strong&gt;Erosion:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Establishing a deep rooted vegetation may help.  What would work best&#xA;is dependent on where you live.  Your local conservation office would&#xA;be able to help with what would work best in your area.  &lt;a href=&quot;https://www.gardeningknowhow.com/special/slope-hill/plants-that-grow-on-slopes.htm&quot; rel=&quot;noreferrer&quot;&gt;This&#xA;site&lt;/a&gt; has some good information for choosing plants on slopes.&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Rip-rap (rock) is also commonly used to help slow erosion.  The size&#xA;you would need would depend on the slope and flow of a the drainage,&#xA;if it would be within a drainage area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qZEzq.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qZEzq.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://www.erosioncontrolnetwork.com/rip-rap/rip-rap.aspx&quot; rel=&quot;noreferrer&quot;&gt;http://www.erosioncontrolnetwork.com/rip-rap/rip-rap.aspx&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Another option would be gabion baskets, however they would be one of&#xA;the most expensive options.  Gabion baskets often look like chain&#xA;link fencing wrapped around rock.  In this way the rocks stay in&#xA;place and the can be placed in a more vertical position.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lX9GB.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lX9GB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://www.svca.on.ca/page.php?page=erosionandfloodcontrol&quot; rel=&quot;noreferrer&quot;&gt;http://www.svca.on.ca/page.php?page=erosionandfloodcontrol&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Flash Flooding:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first thing I would do is establish who is responsible for maintenance of the ditch.  The capacity may need to be re-established or increased if run-off from additional developments have been added to it.  If increasing the capacity of the ditch is not an option, I would see if I could construct either berms (a slight rise in topography) or swales (a minor trough in topography) to direct the water away from any structures on my property.  However, you would need to make sure that you are not increasing flow onto any other neighboring properties or impeding flow from any other properties.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Ponding:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Dry wells are often used to address ponding in yards.  They are&#xA;basically an underground chamber that water is directly to through&#xA;pipes.  Holes in the container let water slowly soak back into the&#xA;surrounding soils.  These need to be sized properly to accommodate&#xA;the volume of water one is trying to remove from the surface of their&#xA;yard.  Also, these may not work well in clay soils that the water&#xA;would percolate slowly into.  More information can be found at the&#xA;source link below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WbH2G.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WbH2G.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://www.svca.on.ca/page.php?page=erosionandfloodcontrol&quot; rel=&quot;noreferrer&quot;&gt;http://www.svca.on.ca/page.php?page=erosionandfloodcontrol&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Rain gardens are a more decorative option that includes water storage&#xA;in a depression, water infiltration,and native vegetation. The basic&#xA;idea of a rain garden is captured in the image below.  Additional&#xA;helpful information can be found &lt;a href=&quot;http://www.raingardennetwork.com/&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.  Some municipalities may&#xA;also have funds available for installing rain gardens on private&#xA;property.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9PPwU.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9PPwU.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source:&#xA;&lt;a href=&quot;http://vienna-wv.com/portal/2013/07/18/what-is-a-a-rain-garden/&quot; rel=&quot;noreferrer&quot;&gt;http://vienna-wv.com/portal/2013/07/18/what-is-a-a-rain-garden/&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Again, I would definitely contact the local jurisdictional authority before I do anything.  There are many government agencies that have codes that need to be met.  Additionally, they would know what works best in your area and may have subsidies that would help defray costs.&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2018-04-15T20:40:43.723" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13920" PostTypeId="1" CreationDate="2018-04-15T22:51:58.123" Score="3" ViewCount="81" Body="&lt;p&gt;There's something I’m still not quite getting about why island arcs are arcs. In the examples I’ve seen, the subducting plate is compared to a knife slicing across the surface of an orange - but it makes sense for the slice of the orange to be an arc, because the knife is a flat plane while the orange is a sphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=S3X3bHXEXfU&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=S3X3bHXEXfU&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Subducting plates, on the other hand, are parts of a spheroid &quot;slicing into&quot; another part of the same spheroid. I’m assuming that because subducting plates are part of the Earth’s crust, they must also be curved, unlike the knife. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So it seems that if the knife is creating an arc &lt;em&gt;because&lt;/em&gt; it's flat relative to the shape of the orange, something must flatten the subducting plate so that it's flatter relative to the plate it subducts under. &lt;strong&gt;Does the &lt;em&gt;compressing force&lt;/em&gt; of the upper plate on the subducting plate flatten it relative to the shape of the upper plate?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="12462" LastEditorUserId="12462" LastEditDate="2018-04-17T08:34:18.117" LastActivityDate="2018-04-17T08:34:18.117" Title="Can the process of subduction flatten the shape of a subducting plate relative to the plate it's going under?" Tags="|geology|plate-tectonics|subduction|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13922" PostTypeId="1" CreationDate="2018-04-16T00:42:09.303" Score="7" ViewCount="104" Body="&lt;p&gt;I know that hurricanes can basically &quot;burn&quot; themselves out of energy if they get too strong, but can the same thing happen with a tornado?&lt;/p&gt;&#xA;" OwnerUserId="12696" LastActivityDate="2020-05-11T18:59:12.100" Title="Can a tornado burn itself out?" Tags="|meteorology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13925" PostTypeId="2" ParentId="13912" CreationDate="2018-04-16T11:44:15.223" Score="6" Body="&lt;p&gt;Water molecules do interact with microwaves and in microwave ovens that operate at 900MHZ- 2.5GHz. This Radar instrument operates using Very High Freq Radio Waves at 193MHz &lt;a href=&quot;https://ieeexplore.ieee.org/stamp/stamp.jsp?arnumber=5649518&quot; rel=&quot;noreferrer&quot;&gt;[1]&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At lower-than-microwave frequencies, the loss factor is much lower, and as a result the wave can penetrate deeper into the ice sheet with minimal absorption. The difference in permittivities between liquid water and solid ice is what allows them to visualise boundaries and identify the subglacial lakes&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From Nasa &lt;a href=&quot;https://www.nasa.gov/content/goddard/airborne-radar-looking-through-thick-ice-during-nasa-polar-campaigns/&quot; rel=&quot;noreferrer&quot;&gt;[2]&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Ice, on the other hand reacts differently depending on the radar's frequency. It reflects high-frequency radio waves, but despite being solid, lower frequency radar can pass through ice to some degree. This is why MCoRDS uses a relatively low frequency—between 120 and 240 MHz. This allows the instrument to detect the ice surface, internal layers of the ice and the bedrock below. &quot;To sound the bottom of ice you have to use a lower frequency,&quot; said John Paden, CReSIS scientist. &quot;Too high a frequency and signal will be lost in the ice.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="12701" LastActivityDate="2018-04-16T11:44:15.223" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13926" PostTypeId="2" ParentId="13913" CreationDate="2018-04-16T13:44:30.080" Score="3" Body="&lt;p&gt;In the figure:&#xA;The top panel is the radar gram measured in depth below ice surface (m). It is flat because when you do the measurement it starts from the surface which is 0m. The distance from the aircraft to the surface would have been relatively constant but the plot starts from the air-ice boundary at 0m. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The middle panel is a cross section measured in m above sea level showing the ice surface and bedrock (black), the hydraulic head (blue) relative to sea level. The hydraulic head is calculated by working out the pressure of the ice sitting on top of the bedrock. It is basically the water table of the ice sheet. Whats important is the differences in hydraulic head (gradient) which can tell you if the water is moving or not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The bottom panel is the reflectivity (black) and specularity (blue) of the basal surface. Specularity is a ratio of reflected to scattered energy. Simply put, high reflectivity means the boundary is wet and high specularity means the boundary is flat (Ice-Water), and low specularity means its rough (Ice Rock). &lt;/p&gt;&#xA;" OwnerUserId="12701" LastActivityDate="2018-04-16T13:44:30.080" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13928" PostTypeId="2" ParentId="5204" CreationDate="2018-04-17T05:02:45.780" Score="1" Body="&lt;p&gt;According to GW theory, global temperature trends toward an equilibrium depending on CO2 concentration. If we could stabilize concentration at today's levels it would take decades to approach equilibrium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we were in the equilibrium state we might have cooler periods due to events like the Pinatubo eruption or a Solar minimum, but then the temperature would return to equilibrium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we continue to increase concentrations, these temporary cooling events might appear to counteract warming, but when they are finished, the temperature will trend up (&quot;with a vengeance&quot;) to the level corresponding to the higher concentration.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2018-04-17T05:02:45.780" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13930" PostTypeId="1" AcceptedAnswerId="13940" CreationDate="2018-04-17T20:10:20.787" Score="2" ViewCount="956" Body="&lt;p&gt;What is the required temperature difference between the sea and the land in order to create a sea breeze? Is there any relation between the temperature difference and the sea breeze intensity? Is there any relation of wind intensity with the rate of increase or decrease in temperature difference?&lt;/p&gt;&#xA;" OwnerUserId="12712" LastEditorUserId="595" LastEditDate="2018-04-18T12:58:13.513" LastActivityDate="2018-04-19T18:15:22.640" Title="Required temperature difference between land and sea for sea breeze" Tags="|meteorology|mesoscale-meteorology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13931" PostTypeId="1" CreationDate="2018-04-18T08:07:09.353" Score="7" ViewCount="4198" Body="&lt;p&gt;I've recently been to Crete, Santorini and am currently on Ios. I've noticed that there is a hazy-ness when I look out on the sea: there's no definitive line where sky meets sea, they just blur together. I feel like I'm in the Truman Show or Stephen King's Dome. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sky is so hazy that when the sun sets the last I see is the sun just disappearing into the haze instead of &quot;dropping&quot; below the horizon like I am used to seeing on Lake Superior. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this phenomenon due to a high amount water molecules (it's April) in the air, that are too think for the sun to penetrate through as it sets? Or is it something else? &lt;/p&gt;&#xA;" OwnerUserId="6195" LastEditorUserId="595" LastEditDate="2018-04-18T12:56:53.583" LastActivityDate="2018-11-02T12:23:56.357" Title="Why is the skyline hazy on the Greek islands?" Tags="|atmosphere|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13932" PostTypeId="1" CreationDate="2018-04-18T11:06:16.290" Score="1" ViewCount="1192" Body="&lt;p&gt;This question is related to the WRF (Weather Research and Forecasting) Model&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I read somewhere that a variable one wants to output, needs to be defined as state variable in the Registry like this (defines the variable QFX, which already is in the output file)&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;state    real  QFX              ij      misc        1         -      rh       &quot;QFX&quot;                   &quot;UPWARD MOISTURE FLUX AT THE SURFACE&quot;          &quot;kg m-2 s-1&quot;      &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;where &quot;h&quot; in &quot;rh&quot; stands for &quot;history&quot;, i.e. the output in the wrfout_d01_.... NETCDF standard output history files.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Can I add any variable as state variable?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example EETA (transpiration), which is defined in the module_sf_ruclsm. (at the physics layer). &lt;a href=&quot;https://www.climatescience.org.au/sites/default/files/WRF_gill_registry.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gill WRF I/O&lt;/a&gt; states &quot;Local variables inside of physics packages are not controlled by the Registry&quot;. So do I need to initialize EETA to the variables in module_surface_driver.F?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I copied the line from QFX and changed the variable name to EETA, but it failed when executing wrf.exe in ./frame/module_domain.F on  line 1174 &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;WRITE(mess,*)'W A R N I N G : Unable to modify mask for ',TRIM(lookee),&amp;amp;&#xA;             '.  Variable not found. File: ',TRIM(fname),' at line ',lineno&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Do I need to edit the namelist to output the variable?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;according to &lt;a href=&quot;https://www.climatescience.org.au/sites/default/files/WRF_gill_registry.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gill WRF I/O&lt;/a&gt; edit &amp;amp;time_control section:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;iofields_filename = &quot;myoutfields.txt” (MAXDOM) &#xA;io_form_auxhist24 = 2 (choose an available stream) &#xA;auxhist24_interval = 10 (MAXDOM, every 10 minutes)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="3419" LastEditorUserId="3419" LastEditDate="2018-04-18T11:27:34.780" LastActivityDate="2018-04-18T11:27:34.780" Title="WRF I/O: Can any variable be output into the wrfout file-stream?" Tags="|wrf|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13933" PostTypeId="2" ParentId="12872" CreationDate="2018-04-18T20:35:36.167" Score="5" Body="&lt;p&gt;I highly recommend this blog article from the &lt;a href=&quot;http://www.planetary.org/blogs/emily-lakdawalla/2012/12110923-grail-results.html&quot; rel=&quot;noreferrer&quot;&gt;Planetary Society&lt;/a&gt;. It is from 2012 but I believe the science is still sound. The author herself, has received recognition for her contribution to communicating space science to the public (She has an asteroid named after her!!)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It doesn't address your question about if there is a flaw in the giant impact hypothesis through an isotopic analysis, but rather through a gravity anomaly analysis from the GRAIL Mission.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Isostasy, gravity, and the Moon: an explainer of the first results of the GRAIL mission. Written by Emily Lakdawalla, 11 December 2012&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The article starts off by giving some information on how gravity anomalies are formed and measured, before delving into the main arguments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Summary (all mistakes are mine), using various analysis's of the gravity anomalies, resulting in 3 further scientific papers linked in the article, the GRAIL mission has determined that the Moon has a highly fractured and highly mixed crust. The crust is alot thinner than previously thought and in some places the crust is nearly or even 0 km deep, allowing mantle minerals to be exposed on the surface. The unexpected porous nature of the crust supports the Earth/Moon common origin, whereas before there was a mismatch in the assumed numbers giving some doubt to the giant impact hypothesis. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The article then finishes off by mentioning an existing theory on how the moon could have formed while still creating the observed features we can see today.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;About halfway through the article, after discussing Airy and Pratt Isostasy, the article starts to mention the observed results. When looking at the Bouguer gravity of the Moon,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Now, the Moon should have local, small-scale variations in crustal density due to local geology; the fact that the variations are small and smooth means (Zuber argued while presenting these results) that impact cratering has completely battered, bashed, fragmented, mixed, and remixed the upper couple of kilometers of the crust, totally homogenizing it. Previous maps of lunar gravity have not had high enough detail to see this beautiful match between topography and gravity; so this is a new GRAIL result.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;a little further on discussing some more results about the density of the moon surface,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;There is one big very surprising thing about this map. The average density is 2550 kilograms per cubic meter. This is much, much lower than what has been assumed for lunar crust; in fact, it's lower than the density of granite. We know what the highlands crust is made of, we have samples of it: the density of the minerals that makes up the crust is around 2800-2900 kilograms per cubic meter. For the Moon's density to be so low, Wieczorek says, it must be very porous, fractured and busted up to give it about 12% void space, to a depth of several kilometers below the surface. This is an important GRAIL result. The mission has given us X-ray vision to see that the Moon's crust is absolutely shattered from the surface for thousands of meters down. In places where the crust is very thin, even the uppermost mantle may be fractured and porous.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Here is where the article starts discussing the mantle minerals, especially Olivine which you mentioned. (emphasis is mine)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This map shows crustal thickness is near zero under a few of the impact basins (particularly Crisium and Moscoviense) and some of the deepest craters inside the south pole-Aitken basin (Humboldtianum, Apollo, and Poincaré). And the crust reaches a high of 60 kilometers on the farside. Kaguya compositional data support the GRAIL conclusions. There's evidence for the mantle mineral olivine being exposed in precisely those places where GRAIL sees the thinnest crust: Crisium, Moscoviense, and Humboldtianum.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The average crustal thickness that Wieczorek and coworkers calculated, 34-43 kilometers, is much lower than has previously been assumed. Why is that important? Because when you work out the math to figure out what the bulk composition of the Moon is, given this thinner crust, you wind up with numbers for the abundance of aluminum that are a much better match to Earth's aluminum abundance than they were before. &lt;strong&gt;Previously, an apparent compositional mismatch had been a problem dogging the giant impact hypothesis for the Moon's formation. The GRAIL result makes for a compositional match.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Near the end of the article, The article mentions Sean Solomon's idea on how the moon could have formed.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Andrews-Hanna pointed out that some theorists have predicted exactly this situation. The paper he cites was by Sean Solomon, principal investigator on the MESSENGER Mercury mission, who was trying to explain how Mercury could have wrinkle ridges caused by global contraction if the Moon does not.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;If you condense the Moon from a ring of debris orbiting Earth following a collision, the first nucleus of the Moon will actually be quite cold. As it grows, the increasing energy of the impacts of stuff onto the proto-Moon would make the Moon's mantle hotter than its deep interior; you could wind up with a cool, solid center surrounded by a hot, liquid mantle. The heat from the mantle would take time to propagate into the interior; as it did, the warming center of the Moon would expand, producing exactly the kind of global extensional stresses that could make this set of dikes. The model has this expansion happening at the correct time, too: before the Moon was 500 million years old, which would be before the end of the basin-forming impacts.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;I hope I actually understood the article correctly and that it helped answer your question. Albeit through a different route.&lt;/p&gt;&#xA;" OwnerUserId="6604" LastActivityDate="2018-04-18T20:35:36.167" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13935" PostTypeId="1" AcceptedAnswerId="13936" CreationDate="2018-04-19T10:07:24.633" Score="1" ViewCount="1007" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aVmc5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aVmc5.png&quot; alt=&quot;Artesian aquifer question&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do not understand how the Artesian aquifer is causing the water in the flowing well to reach a level higher than the ground surface? And what role does the piezometric surface play in it?&lt;/p&gt;&#xA;" OwnerUserId="12718" LastActivityDate="2018-04-19T13:28:54.543" Title="Concept of artesian aquifers and pressure is not clear." Tags="|geology|hydrology|groundwater|hydrogeology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13936" PostTypeId="2" ParentId="13935" CreationDate="2018-04-19T13:28:54.543" Score="6" Body="&lt;p&gt;The red line or piezometric line is the level to which the water wants to rise - if it were allowed to reach hydrostatic equilibrium. Artesian conditions are anywhere where a confined aquifer sits below the hydraulic head level (the level to which the water wants to rise). &#xA;In this case the water is confined and cannot reach the water table even though it wants to - this means it is not at hydrostatic equilibrium. This aquifer is described as having a confining pressure or hydrostatic head. If you put a well into anywhere along this confined aquifer, the water will rise out of the aquifer to the level of red line.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think in your case its a bit confusing as the piezometric line sitting above the whole of the confined aquifer suggests the whole area is artesian but the 'flowing' conditions are only where the piezometric line sits above the actual surface, meaning the water will actually rise above the surface. Another example is that if you were to dig a well, to the left or right of the highlighted area, the water would rise to that level but would still be below the surface so conditions wouldn't be described as 'flowing'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HQHrA.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HQHrA.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.env.gov.bc.ca/wsd/plan_protect_sustain/groundwater/flowing_artesian_wells.pdf&quot; rel=&quot;noreferrer&quot;&gt;http://www.env.gov.bc.ca/wsd/plan_protect_sustain/groundwater/flowing_artesian_wells.pdf&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="12701" LastActivityDate="2018-04-19T13:28:54.543" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13937" PostTypeId="1" AcceptedAnswerId="13938" CreationDate="2018-04-19T14:31:18.977" Score="2" ViewCount="126" Body="&lt;p&gt;In numerous textbooks and papers, the phrase &quot;high-frequency&quot; approximation is used in regards to different types of seismic inversion. What exactly is meant by this? Also, what are the implications if this approximation is in no way satisfied?&lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2018-04-19T15:37:03.183" Title="Seismic inversion: High-Frequency approximation" Tags="|seismic|inversion|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13938" PostTypeId="2" ParentId="13937" CreationDate="2018-04-19T15:37:03.183" Score="4" Body="&lt;p&gt;The propagation of seismic waves is described by the wave equation: $$\mathrm{\nabla \cdot \sigma = \frac{\partial ^2 u}{\partial t^2}}$$&#xA;Where $\sigma$ is the stress and $u$ is the displacement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geometric ray theory is an approximation to the full wave equation where the length scale of variation in seismic wavespeed is much larger than the seismic wavelength (i.e. a high frequency approximation). Typical seismic wavelengths are anything from $\mathrm{\text{~}50-5000~m}$ depending on the application so the ray approximation is generally valid, unless you are trying to resolve very high resolution structure. It is used widely because it is computationally much less expensive than solving the full wave equation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://onlinelibrary.wiley.com/doi/pdf/10.1002/9781119258032&quot; rel=&quot;nofollow noreferrer&quot;&gt;This book&lt;/a&gt; has a very detailed explanation of many aspects of seismic inversion if you need more detail.&lt;/p&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2018-04-19T15:37:03.183" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13939" PostTypeId="1" CreationDate="2018-04-19T17:39:15.240" Score="1" ViewCount="70" Body="&lt;p&gt;Recently I watch a &lt;a href=&quot;https://www.youtube.com/watch?v=YqGH1_tAjlU&quot; rel=&quot;nofollow noreferrer&quot;&gt;video&lt;/a&gt; on which they made a pretty impressively large building complex for housing out of timber. And they were saying that timber is sustainable compared to concrete and such.  From the outset this seems pretty straight forward, trees grow back so long you don't do anything terrible to the ground the grow on (like salt it or build a shopping mall), and concretes components (ie. the stones and calcium oxide. the water does evaporate) does not. However thinking a little harder I know that plants need phosphorous to grow, and currently there is a &lt;a href=&quot;http://theconversation.com/how-the-great-phosphorus-shortage-could-leave-us-all-hungry-54432&quot; rel=&quot;nofollow noreferrer&quot;&gt;shortage of of phosphorous&lt;/a&gt;. &lt;strong&gt;If we are using tress to build our skyscrapers, wouldn't they be locking away our supply of phosphorous for our food and the world's ecosystem? Therefore, is using timber really that sustainable?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;that all said it'll probably be better than concrete and steel, and nothing probably perfectly sustainable.&lt;/p&gt;&#xA;" OwnerUserId="12719" LastActivityDate="2018-04-19T21:39:46.073" Title="How sustainable is timber housing?" Tags="|climate-change|" AnswerCount="1" CommentCount="3" ClosedDate="2018-04-20T05:07:03.903" ContentLicense="CC BY-SA 3.0" />
  <row Id="13940" PostTypeId="2" ParentId="13930" CreationDate="2018-04-19T18:15:22.640" Score="2" Body="&lt;p&gt;So wind is caused by differences in atmospheric pressure which in turn is a result of temperature induced density differences. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;1. Required temperature diference:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A quick search brought up this paper:&#xA;Miller et al. 2003 SEA BREEZE: STRUCTURE, FORECASTING, AND IMPACTS &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2003RG000124&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2003RG000124&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They calculate that a 10 degree difference between land and sea over 20km results in an accelaration of 7.2*10E-3 m/s. Now, this is an estimate. There are many more variables that will affect the complex fluid dynamics of the system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;2. Wind Intensity vs dT.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Absolutely if you increase the temperature gradient (difference) the wind speed will be higher.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;from the paper they mention the sea breeze of Alcoa Bay, South Africa, where the strongest sea breeze occurs in areas with nearby dune fields:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;During the daytime the sand dunes create a region of superheated air immediately overhead, setting up a very strong land-sea temperature difference.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;3. Wind Intensity vs dT/dt&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now this is where it gets complicated. So thinking of this in a mathematical sense, the rate of increase in temperature is not going to matter that much because when calculating the wind speed at a given time what matters most is the absolute temperature difference between land and sea.&#xA;  For a temperature difference to occur the rate of temp change has to be fairly rapid as the system is always trying to reach equilibrium (i.e. remove the temp difference). So naturally if you have a parcel of air, it will reach a higher temperature if the heating is fast vs slow. If it reaches a higher temperature then it will result in a greater wind velocity. But if you wanted to make a more complex model of the system then you would need to look into the rate of change of change in Temp.&lt;/p&gt;&#xA;" OwnerUserId="12701" LastActivityDate="2018-04-19T18:15:22.640" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13942" PostTypeId="2" ParentId="13939" CreationDate="2018-04-19T21:39:46.073" Score="3" Body="&lt;p&gt;Building with timber is more sustainable than building with concrete at least in terms of the production of green house gases.  A timber building is using a raw material, trees, that have been sequestering carbon till they are cut.   Cement, or concrete, on the other hand is made by cooking off carbon dioxide from the calcium carbonate, limestone, to produce the lime which makes up a large part of the concrete.  In the production of lime you have CO2 released from the limestone and from the fuels used to heat the limestone, see &lt;a href=&quot;https://en.wikipedia.org/wiki/Lime_(material)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lime in Wikipedia&lt;/a&gt;.  In addition the timber panels are significantly lighter than the cement components which should also make the timber construction more sustainable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most trees used for timber production are grown in sites that are not generally ideal for other types of agriculture, though this is a gross generalization.  They get their phosphorous through local sources, primarily the soil, so forest growth wouldn't have an impact on the phosphorous used for agricultural processes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following quote from the North Carolina State University project site summarizes the overall impact on timber construction.  It is important to note that until the advent of CLT, cross laminated timber, it was effectively impossible to build larger structures out of wood.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;CLT paneling is also thermally efficient, requiring 1/3 the heating and cooling energy compared to other traditional building systems. CLT paneling is also beneficial to the environment.  Wood is the only major building material that grows naturally and is renewable, CLT also outperforms steel and concrete in terms of embodied energy required to make the product. It also has a less of an effect on air pollution (stores carbon) and water pollution. &lt;a href=&quot;https://research.cnr.ncsu.edu/blogs/clt-panels/home/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CLT Panels USA&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2018-04-19T21:39:46.073" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13943" PostTypeId="1" AcceptedAnswerId="13946" CreationDate="2018-04-19T22:06:22.710" Score="1" ViewCount="1178" Body="&lt;p&gt;I'm building an R package (&lt;a href=&quot;https://github.com/ibarraespinosa/wrftools&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://github.com/ibarraespinosa/wrftools&lt;/a&gt;) to read namelist.wps and return a dynamic map which you can make zoom. In my case, it would be very beneficial because writing a namelist.wps can be tricky. The problem is that I need to know the EPSG or spatial reference (&lt;a href=&quot;http://spatialreference.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://spatialreference.org/&lt;/a&gt;) to transform the spatial data to WGS84. &#xA;Hence:&#xA;&lt;strong&gt;What are the EPSG code for:&#xA;Lambert conformal, Mercator and polar stereographic projections&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit 1: According to the &lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/users/docs/user_guide_V3/ARWUsersGuideV3.9.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;WRF Manual&lt;/a&gt; , page 3-10: &quot;As a general guideline, &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;the &lt;strong&gt;polar stereographic&lt;/strong&gt;  projection is best suited for high-latitude WRF domains, &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;the &lt;strong&gt;Lambert conformal&lt;/strong&gt; projection is well suited for mid-latitude domains, and &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;the &lt;strong&gt;Mercator projection&lt;/strong&gt; is good for low-latitude domains or domains with predominantly west-east extent.&quot;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;What I want to do is to tell R how to recognize these projections (spatial references), so that I can plot into the map.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: The example is from Brazil but the idea is that it can be used anywhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to know:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If projection is &lt;em&gt;lambert&lt;/em&gt;, the EPSG code is XX or the spatial reference is &quot;+proj=lcc +lat_1=YY...&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/c5OEC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/c5OEC.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6489" LastEditorUserId="5594" LastEditDate="2018-04-23T06:31:33.810" LastActivityDate="2018-04-27T06:07:23.570" Title="WRF: EPSG code or spatial reference for Lambert conformal, Mercator and polar stereographic projections" Tags="|meteorology|wrf|wrf-chem|" AnswerCount="1" CommentCount="6" ClosedDate="2018-04-20T07:26:52.213" ContentLicense="CC BY-SA 3.0" />
  <row Id="13944" PostTypeId="2" ParentId="9025" CreationDate="2018-04-20T00:39:43.143" Score="4" Body="&lt;p&gt;Tropospheric ozone is a significant greenhouse gas (see e.g. &lt;a href=&quot;http://www.ipcc.ch/publications_and_data/ar4/wg1/en/faq-2-1.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC AR4&lt;/a&gt;) and has well established negative effects on crop yields. For example, &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S1352231008009424&quot; rel=&quot;nofollow noreferrer&quot;&gt;Van Dingen et al (2009)&lt;/a&gt; evaluated yield losses of up to about 15% globally, depending on the crop.&lt;/p&gt;&#xA;" OwnerUserId="859" LastActivityDate="2018-04-20T00:39:43.143" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13945" PostTypeId="1" CreationDate="2018-04-20T02:01:12.950" Score="4" ViewCount="174" Body="&lt;p&gt;In &lt;a href=&quot;https://journals.ametsoc.org/doi/full/10.1175/JPO-D-15-0046.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; paper, the authors detail the methods to calculate the stream function $\psi$ from velocity data in the case of the global ocean (i.e., multiply connected domains).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The general idea is to use velocity to calculate the vorticity $\zeta$ and, with that, calculate the stream function by solving the Poisson equation:&#xA;$$\nabla^2\psi=\zeta$$&#xA;The difficulty of the problem is to specify the boundary conditions. As we do not want a flow across the boundary, we require $\psi=\mu_k$ on all the coastlines, with the value of $\mu_k$ being a constant to be determined for each different coastline (i.e., each island/continent).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To do this one can use the so-called Godfrey's islands rule that follows from requiring that the circulation around each island should be constant.&#xA;At the end of the day, one should solve a system of equations that relate the $\mu_k$ and the derivatives of $\psi$ normal to the coastlines (eq. 19 in the paper):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\sum_k\mu_k\int_{\partial I_k}\partial_n\psi_j~ds+\int_{\partial I_k}\partial_n\psi_0~ds=\int_{\partial I_k}\mathbf{m}\cdot ds$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;BUT&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shouldn't the normal derivative be zero in order to have no-flow?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If yes, probably not, but if yes, this would imply that all the $\mu_k$ would be zero and one could avoid to solve the system altogether...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What am I missing?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Side questions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1- How can one calculate the normal derivative with numerical data when the coastline is &quot;segmented&quot; and the normal vector not well defined? For example in this case:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;   ____&#xA;__|xxxx|___&#xA;xxxxxxxxxxx&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;2- Does anyone know of a freely-available code for solving this problem? I am currently struggling with the normal derivatives...&lt;/p&gt;&#xA;" OwnerUserId="6001" LastActivityDate="2018-04-20T02:01:12.950" Title="Godfrey's island rule (stream function in multiply connected domains)" Tags="|oceanography|fluid-dynamics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13946" PostTypeId="2" ParentId="13943" CreationDate="2018-04-20T05:33:20.570" Score="1" Body="&lt;p&gt;Spatial reference systems are coordinate systems that can be geographical coordinate systems defined on a model ellipsoid or projection coordinate systems.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A projection coordinate system is defined by four groups of parameters: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;model ellipsoid, &lt;/li&gt;&#xA;&lt;li&gt;projection type&lt;/li&gt;&#xA;&lt;li&gt;projection parameters&lt;/li&gt;&#xA;&lt;li&gt;measurement unit&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;EPSG codes refer to complete spatial reference systems or model ellipsoids.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You are saying that you want an EPSG code for projection coordinate systems that  use WGS84 as model ellipsoids and Mercator, Lambert conformal conical, and stereographic projections. These projections require additional parameters such as the central meridian and origin latitude. Choice of parameters depends on your region of interest.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could start with &lt;strong&gt;&lt;a href=&quot;http://spatialreference.org/ref/epsg/4326/&quot; rel=&quot;nofollow noreferrer&quot;&gt;EPSG:4326&lt;/a&gt;&lt;/strong&gt; which is a geographical coordinate system with degrees as units.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Next, since your region of interest seems to be in the south of Brazil, consider &lt;strong&gt;&lt;a href=&quot;http://spatialreference.org/ref/epsg/32722/&quot; rel=&quot;nofollow noreferrer&quot;&gt;EPSG:32722&lt;/a&gt;&lt;/strong&gt; that stays for &lt;strong&gt;Universal Transverse Mercator zone 22S&lt;/strong&gt; and uses the WGS84 ellipsoid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a Lambert Conformal Conic projection consider &lt;strong&gt;&lt;a href=&quot;https://epsg.io/102015&quot; rel=&quot;nofollow noreferrer&quot;&gt;ESRI:102015&lt;/a&gt;&lt;/strong&gt; that stays for &lt;strong&gt;South America Lambert Conformal Conic&lt;/strong&gt;. This spatial reference uses a model ellipsoid that is different from WGS84, so this might be a problem for you. The standard parallel numbers for this projection are 5S and 42S meaning that the distortion would be greater for regions that lie away from these latitude, i.e. the Northern hemisphere or the Antarctic regions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally for a Stereographic Polar you might consider &lt;strong&gt;&lt;a href=&quot;https://epsg.io/3031&quot; rel=&quot;nofollow noreferrer&quot;&gt;EPSG:3031&lt;/a&gt;&lt;/strong&gt;. An &lt;strong&gt;Antarctic Polar Stereographic&lt;/strong&gt; projection coordinate system that uses WGS84 as a model ellipsoid.&lt;/p&gt;&#xA;" OwnerUserId="2511" LastEditorUserId="2511" LastEditDate="2018-04-27T06:07:23.570" LastActivityDate="2018-04-27T06:07:23.570" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13948" PostTypeId="1" CreationDate="2018-04-20T11:40:45.173" Score="1" ViewCount="110" Body="&lt;p&gt;We are trying to couple our land surface model into WRF. As a first step, we'd like to know what is the minimal list of variables required by such coupling?&lt;/p&gt;&#xA;" OwnerUserId="1376" LastActivityDate="2018-04-20T11:40:45.173" Title="WRF: minimal list of variables required by coupling a land surface model to the whole system" Tags="|numerical-modelling|wrf|land-surface|land-surface-models|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13953" PostTypeId="1" AcceptedAnswerId="13960" CreationDate="2018-04-20T23:51:40.813" Score="4" ViewCount="364" Body="&lt;p&gt;The July 2007 issue of the National Geographic Magazine dedicates several pages to &lt;strong&gt;&quot;Climate Change&quot;&lt;/strong&gt; and &lt;strong&gt;&quot;Global Warming&quot;&lt;/strong&gt;.  The author explains in detail the Earth's movements and how they provoke great climate shifts.  &lt;strong&gt;&quot;Wobble&quot;&lt;/strong&gt; is one of the four movements listed and is described as follows:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;&quot;Earth slowly wobbles like a top as it spins on its axis, which shifts back and forth about every 20,000 years. The result: &lt;strong&gt;About 11,000 years from now, winter solstice in the Northern Hemisphere will be in July.&lt;/strong&gt;&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Although I know exactly what a top is, and how it spins, I find it hard to understand how wobbling is expected to bring about that forecast.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Can anyone explain more didatically how such a shift is expected to happen? How the wobble movement is doing it?&lt;/li&gt;&#xA;&lt;li&gt;Is such an astronomic phenomenon accepted by scientists unquestionably?&lt;/li&gt;&#xA;&lt;li&gt;If winter is expected to be in July 11,000 years from now and such a shift is under way right now, does it mean that winter in the NH is slowly moving towards July and that, perhaps, 5,000 years from now winter solstice will be in March? &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="6370" LastEditorUserId="6370" LastEditDate="2018-04-21T01:55:18.697" LastActivityDate="2018-04-22T08:48:39.690" Title="Winter in the Northern Hemisphere in July? Can anyone explain it?" Tags="|geophysics|climate-change|climate-models|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13954" PostTypeId="2" ParentId="13953" CreationDate="2018-04-21T02:58:27.010" Score="2" Body="&lt;p&gt;Due to &lt;a href=&quot;https://en.wikipedia.org/wiki/Axial_precession&quot; rel=&quot;nofollow noreferrer&quot;&gt;Axial precession&lt;/a&gt; the Earth's axis changes direction with a period of 26,000 years as in the diagram:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kgaIU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kgaIU.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If our calendar was defined by the position of Earth in it's orbit relative to the &quot;fixed&quot; stars, the North Pole will be tilted away from the sun in July 11,000 years hence.&#xA;However, according to &lt;a href=&quot;http://curious.astro.cornell.edu/about-us/160-our-solar-system/the-earth/seasons/74-will-the-seasons-change-due-to-precession-intermediate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Will the seasons change due to precession? &lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;months are defined by seasons and so &lt;strong&gt;winter in the Northern hemisphere will never occur during June&lt;/strong&gt;. At any point in future, the Northern hemisphere will experience summer during June and winter during December, but due to precesion, the months will correspond to different positions of the Earth's orbit around the Sun.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2018-04-21T16:10:54.043" LastActivityDate="2018-04-21T16:10:54.043" CommentCount="9" ContentLicense="CC BY-SA 3.0" />
  <row Id="13955" PostTypeId="2" ParentId="9511" CreationDate="2018-04-21T05:30:36.933" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Has the Earth had it's wobble that causes the seasonal variation in&#xA;  solar energy in the northern and southern hemispheres for it's entire&#xA;  history?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The Earth wobble this is because it follows precession of equinox cycle and what you mean by wobble is that nutation happens. This is the torque T produce by angular velocity ò multiply by angular momentum L. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;T = ò x L&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One complete cycle takes 26,000 years on average and Earth was already there for 4 billion years in approximate base on carbon dating of rocks. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;4,000,000/26,000 = 153,800 Precession Cycles&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One cycle is enough to change different variation of season such as a month of Decemeber could face summer, winter, autumn and spring for the whole duration of precession. But what really impacts a total climate change is base on Milankovitch cycle which he deduce a statement that obliquity in axial precession from 22.1 to 24.5 degrees change so much climate as to compare to our present 23.5 degrees tilting that could happen for every 100,000 years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;100,000/26,000 = 3.8 or 4 Precession Cycles&lt;/p&gt;&#xA;&#xA;&lt;p&gt;153,800/4 = 38,450 Precession Seasonal Milankovitch Changes Aprox.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's a lot of time to conclude that Earth had undergone seasonal variation for a very very long time. This already answer the question 2.  Is this variation evident in the geologic record or is it an open question?&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Could a meteor impact like that which killed the dinosaurs 66 million&#xA;  years ago have altered or created the wobble?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There are theories that linked the extinction of dinosaurs or meteor impact million years ago such as India-Eurasia Collision which created the modern Himalayan which causes flattening the pole and elongating the surface that changes orientation on axial tilting. Meteor impact theory might not be enough to killed the dinosaurs 66 million years ago. Climate should be seen as a major factor that makes extinction for a certain species. Yet smaller biodiversity are more likely to be adaptive to harsh climate condition enable them to survive and evolve later years. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Are there any factors dampening or increasing the seasonal wobble over&#xA;  time?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Wobble might increase or decrease over time when plate tectonics shifts postion. This is because the distribution of plates varies to the degree of rotation of the Earth. Such as in our generation 2000 AD, looking on geodetic Earth and bathymetric structure leads you to observe flattening of the pole and elongation at equator. The contribution of Himalayan mountain and subduction of the Pacific trench affects the speed rotation thus altering different cycles calculated such as precession and obliquity of the true pole.   &lt;/p&gt;&#xA;" OwnerUserId="12729" LastEditorUserId="725" LastEditDate="2018-04-21T07:33:42.323" LastActivityDate="2018-04-21T07:33:42.323" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13958" PostTypeId="1" CreationDate="2018-04-22T00:26:23.547" Score="1" ViewCount="85" Body="&lt;p&gt;What kind of underlying material are atolls like the Maldives built upon? Is there bedrock down there, or is it just sand and coral?&lt;/p&gt;&#xA;" OwnerUserId="12740" LastActivityDate="2018-04-22T00:26:23.547" Title="What lies beneath the Maldives?" Tags="|bedrock|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13959" PostTypeId="1" AcceptedAnswerId="14015" CreationDate="2018-04-22T04:56:56.610" Score="5" ViewCount="1220" Body="&lt;p&gt;When studying the paleoenvironment of the Oligocene epoch, a period in Earth's history spanning from 34 to 23 million years ago, I had a really hard time understanding what the climate was like in comparison to today:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Paleogene period general temperature decline is interrupted by an Oligocene 7-million-year stepwise climate change. A deeper 8.2°C, 400,000-year temperature depression leads the 2°C, seven-million-year stepwise climate change 33.5 Ma (million years ago). The stepwise climate change began 32.5 Ma and lasted through to 25.5 Ma, as depicted in the PaleoTemps chart. The Oligocene climate change was a global increase in ice volume and a 55 m (181 feet) decrease in sea level (35.7–33.5 Ma) with a closely related (25.5–32.5 Ma) temperature depression. The 7-million-year depression abruptly terminated within 1–2 million years of the La Garita Caldera eruption at 28–26 Ma. A deep 400,000-year glaciated Oligocene–Miocene boundary event is recorded at McMurdo Sound and King George Island.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This statement &lt;a href=&quot;https://en.wikipedia.org/wiki/Oligocene#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;from Wikipedia&lt;/a&gt; struck me as vague and therefore confusing. So in plain, simple English and in general, what was the climate of the Oligocene like in comparison with today's climate?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastEditorUserId="4985" LastEditDate="2018-04-24T16:53:28.487" LastActivityDate="2023-08-25T09:19:22.730" Title="How Hot was the Oligocene?" Tags="|temperature|paleoclimatology|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13960" PostTypeId="2" ParentId="13953" CreationDate="2018-04-22T08:48:39.690" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Can anyone explain more didatically how such a shift is expected to&#xA;  happen? How the wobble movement is doing it?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;First, it's probably a bad approach to think of it as a shift.  It's a rotation.  similar to a spinning top.   &lt;a href=&quot;http://hyperphysics.phy-astr.gsu.edu/hbase/top.html&quot; rel=&quot;noreferrer&quot;&gt;It's called precession.&lt;/a&gt;  It's always been there - (so to speak).  It's part of Earth's motion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth is sufficiently massive and space, sufficiently empty that there's effectively zero resistance and the Earth's precession is permanent and largely consistent.  (unlike a top that slows down due to friction from the ground and air resistance).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth's precession shifts a tiny bit due to the sun, moon and gravity from other planets but those adjustments are very slow and not relevant to your question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As Earth's precession completes one rotation every 22,000 years (give or take), over a human lifetime that's about 1.5 degrees or 1.5 days, which is pretty small and easily missed by anyone not taking very careful measurements. That doesn't affect calendars however.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Calendars are a little complicated, and I'm not sure it's necessary to go into that in detail for your question.   Calendars also can be adjusted to match Earth's orbit.   Any un-adjusted calendar will eventually mess things up like putting July in winter, but that has nothing to do with the 22,000 year precession.   365.25 days (a leap year every 4 years), was inaccurate enough to lead to &lt;a href=&quot;https://www.historic-uk.com/HistoryUK/HistoryofBritain/Give-us-our-eleven-days/&quot; rel=&quot;noreferrer&quot;&gt;the year that lost 11 days&lt;/a&gt; in the UK in 1752.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;365.25 days (Julian calendar) is much more accurate than 365 days (which loses a day every 4 years (in effect, a 365 day year would put July in winter in 720 years, not 11,000).  Any movement of winter across the calendar depends on how good the calendar is, &lt;strong&gt;NOT&lt;/strong&gt; earth's precession.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;365.242 days (&lt;a href=&quot;https://en.wikipedia.org/wiki/Gregorian_calendar&quot; rel=&quot;noreferrer&quot;&gt;Gregorian calendar&lt;/a&gt;), or 97 leap years every 400 years is better than the Julian (1 every 4).  Having an accurate accounting of leap years and being able to add or remove one as needed, will keep winter in the winter months for as long as we need to, much longer than 11,000 years.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What changes with Earths precession is the position of the stars.  The sky will shift depending on where Earth is in it's 22,000 year wobble.  Similarly, the North star won't always be the North star.   The night sky will look shifted by about 46 degrees in 11,000 years (some of the stars will have moved over that time-frame as well, but lets ignore that for now).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You've herd the term &quot;Age of Aquarius&quot;.   &lt;a href=&quot;https://en.wikipedia.org/wiki/Astrological_age&quot; rel=&quot;noreferrer&quot;&gt;The astrological ages&lt;/a&gt; each last about 1,800-2,000 years, and the cycle of 12 ages corresponds to Earth's 22,000 year wobble.  Note, that article says 25,860 years and your quoted 22,000 years.  The solar system also wobbles, so how those wobbles add up can give different estimates.   If you use 22,000 or 25,860 or 25,771 or 26,000 or 23,000 on average, the different numbers don't change the answer to this question.   &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles#Apsidal_precession&quot; rel=&quot;noreferrer&quot;&gt;This explains the variation in the numbers used&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is such an astronomic phenomenon accepted by scientists&#xA;  unquestionably?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Absolutely, 100%, unquestionably yes.  This is accepted, measured, confirmed and can be modeled and explained.  It's 100% accepted science.  Even &lt;a href=&quot;http://www.crystalinks.com/precession.html&quot; rel=&quot;noreferrer&quot;&gt;the ancients were able to observe this&lt;/a&gt; with careful measurement, though they couldn't accurately explain it.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If winter is expected to be in July 11,000 years from now and such a&#xA;  shift is under way right now, does it mean that winter in the NH is&#xA;  slowly moving towards July and that, perhaps, 5,000 years from now&#xA;  winter solstice will be in March&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As the assumption is flawed, then both no and yes.  With an imperfect calendar, then this would happen and the rate would depend on the accuracy of the calendar as noted above (not precession).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because we use a very accurate calendar that allows for adding and removing a leap year as needed, no &quot;drifting&quot; of the solstices across the months will happen.   There will be some yearly variation as the solstice is a precise point in Earth's orbit, so it happens not only on a day but at a precise time, it might be December 21 one year and December 22 the next year, but every year our calendar gets &quot;messed up&quot; by about 6 hours, and every 4 years, that 6 hour error is mostly corrected.   Jupiter also accelerates or decelerates the Earth in it's orbit and Earth's orbital speed varies depending on how close to perihelion and aphelion, so there's some variation year to year, but there's no movement across the calendar over 11,000 years.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2018-04-22T08:48:39.690" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13963" PostTypeId="1" AcceptedAnswerId="14143" CreationDate="2018-04-22T16:35:56.293" Score="5" ViewCount="4371" Body="&lt;p&gt;Which plant is the most efficient in making oxygen for it's weight? I want to think it is the greenest plant with more leaves and least                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  trunk in full sun?&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T08:18:07.083" LastActivityDate="2019-08-29T08:18:07.083" Title="Which plant produces the most oxygen?" Tags="|oxygen|plant|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="13966" PostTypeId="2" ParentId="13959" CreationDate="2018-04-23T09:30:15.820" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zdaGS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zdaGS.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Modified from &lt;a href=&quot;http://dx.doi.org/10.1029/2008PA001683&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cramer et al. 2009&lt;/a&gt; by adjusting to the Gradstein et al. 2012 timescale. In black, it is the Pacific trend; in blue the North Atlantic and in green the South Atlantic.&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This graph shows the Cenozoic variations of $\delta\ce{^{18}O}_{Cibicidoides}$ according to Cramer et al. 2009. This proxy is thought to vary according to variations of deep sea temperature (to simplify) and thus should reflect the climate state at a given time. As negative values of $\delta\ce{^{18}O}_{Cibicidoides}$ corresponds to warmer temperature than positive ones, the graph is oriented accordingly. I highlighted the beginning (33.9Ma) and end (23.03Ma) of the Oligocene in red.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Oligocene starts with a rapid cooling (linked to the East Antarctic glaciation, see for instance &lt;a href=&quot;http://dx.doi.org/10.1029/JC082i027p03843&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kennett 1977&lt;/a&gt;, &lt;a href=&quot;http://science.sciencemag.org/content/292/5517/686&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zachos et al. 2001&lt;/a&gt;, &lt;a href=&quot;https://pdfs.semanticscholar.org/4801/61fc1d6ba9986b27c97bde8c0ed0096b630e.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;De Conto &amp;amp; Pollard 2003&lt;/a&gt;). Yet as you can see on the graph the temperature is still warmer than the late Miocene to Recent period. Some regional trends then show a moderate warming at the end of the Oligocene that culminates in the middle Miocene climatic Optimum, ca. ten million years later.&lt;/p&gt;&#xA;" OwnerUserId="87" LastActivityDate="2018-04-23T09:30:15.820" CommentCount="6" ContentLicense="CC BY-SA 3.0" />
  <row Id="13970" PostTypeId="1" CreationDate="2018-04-23T15:33:52.450" Score="5" ViewCount="70" Body="&lt;p&gt;I know that the earth has atmospheric banding like the gas giants.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I want to know is why six in specific? What physical processes or equations determine the number of atmospheric bands on a planet with an atmosphere?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also I'm not sure if the intertropical convergence zone counts as a 'band'. If it does the same question holds for why we have seven bands.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NOTES:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a follow up to&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://physics.stackexchange.com/questions/163805/why-doesnt-earths-atmosphere-form-bands-due-to-different-rotational-speeds&quot;&gt;https://physics.stackexchange.com/questions/163805/why-doesnt-earths-atmosphere-form-bands-due-to-different-rotational-speeds&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And has been reposted due to comment request from here&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://physics.stackexchange.com/questions/400417/why-does-the-earth-have-six-atmospheric-bands?noredirect=1#comment897797_400417&quot;&gt;https://physics.stackexchange.com/questions/400417/why-does-the-earth-have-six-atmospheric-bands?noredirect=1#comment897797_400417&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12761" LastActivityDate="2018-04-23T15:33:52.450" Title="Why does the Earth have six atmospheric bands?" Tags="|meteorology|atmosphere|" AnswerCount="0" CommentCount="1" ClosedDate="2018-04-24T15:09:04.333" ContentLicense="CC BY-SA 3.0" />
  <row Id="13972" PostTypeId="1" CreationDate="2018-04-23T18:55:19.677" Score="7" ViewCount="893" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NgeoV.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NgeoV.png&quot; alt=&quot;Chernier_ridges&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the attached image, we can see &lt;strong&gt;chenier&lt;/strong&gt; &lt;strong&gt;ridges&lt;/strong&gt; and &lt;strong&gt;strand plains&lt;/strong&gt;. How are they formed and what is the involvement of &lt;strong&gt;rip&lt;/strong&gt; and &lt;strong&gt;longshore currents&lt;/strong&gt; in their formation?&lt;/p&gt;&#xA;" OwnerUserId="12718" LastActivityDate="2020-01-27T14:15:19.527" Title="How are chenier ridges and strand plains formed at wave dominated coastlines?" Tags="|geology|sedimentology|ocean-currents|waves|" AnswerCount="2" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13974" PostTypeId="1" CreationDate="2018-04-24T03:41:51.273" Score="8" ViewCount="105" Body="&lt;p&gt;How can scientists know where the earliest continents were located?  Supposedly, Pangaea has formed, re-formed, moved all around, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do paleogeologists primarily rely on paleomagnetism, paleontology, or what?&lt;/p&gt;&#xA;" OwnerUserId="12767" LastEditorUserId="87" LastEditDate="2018-04-24T07:43:41.767" LastActivityDate="2018-04-24T14:15:56.207" Title="How, exactly, do scientists know location of earliest continents?" Tags="|plate-tectonics|paleogeography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13976" PostTypeId="2" ParentId="13974" CreationDate="2018-04-24T14:15:56.207" Score="6" Body="&lt;p&gt;Well, the really earliest continents, the answer is we don't. As you go further back the uncertainties get larger and larger. It has been speculated that there have been around 4-5 super continents like Pangaea. Before Pangaea there was Rodinia, but before that it gets more and more sketchy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The oldest ocean floor is only Jurassic. So ocean palaeomagnetism is only good back to the Jurassic, but can be extrapolated a bit beyond that. You have continental magnetism and this helps place the palaeo-latitude - for example, we know the UK was just south of the Equator in the early Palaeozoic. That doesn't give you relative location but is an important piece of the jigsaw.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other is stratigraphy. Yes that includes palaeontology, but before the Palaeozoic, palaeontology is limited (eg. do Ediacaran species have global or regional distribution? what about earlier single celled organisms?). It can also include rock correlations, isotope signatures, etc. For example, the Lewisian Gneiss is a piece of Archaeon craton in NW Scotland that has some well studied dyke sequences. If you find similar gneisses elsewhere with the same dates and dykes with the same chemical signatures, then you can hypothesise they were a part of the same unit and they split after the dyke intrusion.&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2018-04-24T14:15:56.207" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13977" PostTypeId="1" CreationDate="2018-04-24T16:56:24.273" Score="4" ViewCount="131" Body="&lt;p&gt;Why are cross stratified conglomerates found in deposits of fan deltas? I know that fan deltas are alluvial fans that deposit directly into the sea, hence they are poorly sorted.But could not understand the reason for presence of cross stratified conglomerates.&lt;/p&gt;&#xA;" OwnerUserId="12718" LastEditorUserId="12718" LastEditDate="2018-04-27T12:52:39.783" LastActivityDate="2018-04-27T12:52:39.783" Title="Presence of cross stratified conglomerates in fan deltas" Tags="|geology|sedimentology|waves|tides|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13978" PostTypeId="2" ParentId="13829" CreationDate="2018-04-24T18:10:49.650" Score="4" Body="&lt;p&gt;The information you provide is rather limited, however, I want to try and disentangle this. The way I see it, you are mixing three different concepts in your questions. I will work through the semi-circle, through the elliptical towards the hyperbolic assumption.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Semi-Circle&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;This is a GIF of a central source emiting a wave in a homogeneous space: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RJ1cG.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RJ1cG.gif&quot; alt=&quot;https://en.wikipedia.org/wiki/Wave_equation#/media/File:Spherical_wave2.gif&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can stop the gif at any time (drag it with your mouse) and all wavefronts will be concentric. You can also see this, when you look at the wave equation. Changes in time equal the velocity times changes in space. If the velocity is constant, a change in time will cause a equal change of wave propagation in any available direction. While often, we work in (x,y,z)-coordinates, here it's easiest to assume that our wave source is at $(0,0,0)$ and if our propagation is equal in all directions, our vector pointing to these points in space is the radius of a perfect sphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, if we're looking at a half-space like we do in seismics, we have a half-sphere and if we scale back to 2D we have a semi-circle surrounding our source. So if we dig up a huge patch of subsurface and place receivers all around our source, those equally distant from the source should respond at the same time after igniting the source.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Ellipsis&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;In Fig. 13 you see the semi-circle. There are several important things to note in this image. The first would be the receiver. The receiver is off-center, but all those receivers in the semi-circle example are too. What makes this different, is that instead of several receivers recording the wave simultaneously, here, it's one singular receiver. Additionally, before our source was nice and centric, now it's off-center. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, this is not enough to make sense of Fig. 13. Firstly, for the semi-circle we were looking at direct waves. In Fig. 13 we see reflected waves. Now, they assume constant velocity again, which means there clearly must be a density change to make a reflection happen. This brings us to a simple theoretical question: &quot;I have a measurement with the traveltime $T$. Which locations in the subsurface would have to have a density change to explain my measurement of $T$?&quot; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So essentially, you are constructing a plane where the ray path from the source toward the plane, added to the ray path from that incident point on the plane to the receiver is always of the length $T$. Luckily, this is exactly how a half ellipse is formed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can actually try this with a string. Take a string of the length $T$, fix one end on the source location, one at the receiver location and then put a pen in the sling and trace the outmost location you can reach with the pen in the sling. You have created a surface below your acquisition, which could all have caused a response at your receiver at the time $T$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fun fact: If you put the source and the receiver back to location $x=0$, your ellipsis becomes a circle again. It's not the semi-circle from before, as before we had a direct wave, now we're looking at a surface of equal reflection traveltime. You can see this in the following figure &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Ellipse-var.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;CC-BY-SA Ag2gaeh&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YVXXb.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YVXXb.png&quot; alt=&quot;https://en.wikipedia.org/wiki/Ellipse#/media/File:Ellipse-var.svg&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Hyperbola&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Figure 14 will again take us a step closer to migration. Before, you looked at One source off-center and one receiver off-center. Now we switch gears again. Let's look at the easiest case here, $x=0$. Here the source and the receiver are at the same location, so the travel time $T_0$ to the imaging point I is equal in length before and after reflection from the subsurface point. But from before we know that this place I could be anywhere on a semi-circle in the subsurface (which would be an ellipse, if it wasn't for the fact the $S=R$, as we saw before).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So we need something to convince our math, that instead of placing our image point I &quot;anywhere on a semi-circle&quot;, we want the exact location. Here, we have several ways to look at it. If the image point $I$ in the subsurface is actually a point, we call it diffractions. The special property of diffractions is, that they will always reflect your wave right back at you (they diffract the wave, so they scatter the wave in &lt;em&gt;all&lt;/em&gt; directions, hence, also back at you). So if you place your source and your receiver at location x=1 in this image, we can construct a triangle between the points $I$, $x=0$ and $x=1$. That means our traveltime T_1 can be calculated with good ol' Pythagoras ($a^2 + b^2 = c^2$):&#xA;$$1^2 + (T_0/2)^2 = (T_1/2)^2,$$&#xA;and we can do this for every point so that:&#xA;$$T_N = 2 * \sqrt(N^2 + T_0^2/4)$$&#xA;and then:&#xA;$$T_N = T_0 * \sqrt((2N/T_0)^2 + 1)$$&#xA;This coincidentally describes the eccentricity of a hyperbola. This is one way to go about finding diffraction hyperbolae, there are several others, but I tried to stick with the provided figures.&lt;/p&gt;&#xA;" OwnerUserId="507" LastActivityDate="2018-04-24T18:10:49.650" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13979" PostTypeId="1" AcceptedAnswerId="13982" CreationDate="2018-04-24T18:44:37.270" Score="0" ViewCount="1592" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ilQfJ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ilQfJ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why do Rivers flowing into Pakistan come from either Afghanistan or &lt;a href=&quot;http://theconversation.com/how-india-and-pakistan-are-competing-over-the-mighty-indus-river-77737&quot; rel=&quot;nofollow noreferrer&quot;&gt;India&lt;/a&gt; and not from inland mountains?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it possible for Pakistan to source fresh water from its northern mountains avoiding India or Afghanistan so that the water can feed the entire nation?&lt;/p&gt;&#xA;" OwnerDisplayName="user12774" LastEditorUserId="10681" LastEditDate="2018-08-17T12:42:56.087" LastActivityDate="2018-08-17T12:42:56.087" Title="Rivers flowing into Pakistan" Tags="|hydrology|rivers|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13980" PostTypeId="1" CreationDate="2018-04-24T20:01:47.077" Score="3" ViewCount="171" Body="&lt;p&gt;In New Zealand today, the Alpine fault features two pieces of continental crust sliding past each other, with the whole Eastern side of the South Island falling on the Pacific plate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But when New Zealand separated from Gondwanaland, it was entirely on it's own plate with the Pacific plate subducting beneath it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How did most of the south island end up colliding with the very plate it used to be travelling with?&lt;/p&gt;&#xA;" OwnerUserId="12775" LastEditorUserId="28050" LastEditDate="2018-04-25T14:24:19.607" LastActivityDate="2018-04-27T16:52:32.647" Title="How did New Zealand's continental crust get split between two plates?" Tags="|plate-tectonics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13981" PostTypeId="1" CreationDate="2018-04-25T11:58:40.753" Score="1" ViewCount="155" Body="&lt;p&gt;The Eparchean Unconformity forms the boundary between Proterozoic Nagari Quartzite and Archean Granite. Now, the Gulcheru Quartzite marks the onset of sedimentation , after Eparchean Unconformity in the Cudappah Basin. So, are 'Proterozoic Nagari Quartzite' and 'Gulcheru Quartzite', the same units?&lt;/p&gt;&#xA;" OwnerUserId="12718" LastEditorUserId="2570" LastEditDate="2018-04-25T16:09:22.167" LastActivityDate="2018-04-25T16:09:22.167" Title="Difference between Proterozoic Nagari Quartzite and Gulcheru Quartzite" Tags="|stratigraphy|time|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13982" PostTypeId="2" ParentId="13979" CreationDate="2018-04-25T16:06:52.307" Score="2" Body="&lt;p&gt;I'm a bit confused why you say the water particularly comes from Afghanistan and India.&lt;br&gt;&#xA;Perhaps the colors on that graphic end up being a bit confusing...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As your own graphic does indicate, the Indus basin basically runs the spline of Pakistan.  One could argue many many other countries aren't nearly as lucky, with rivers quickly cutting across their country, and so are under much more dependence on countries upstream (and owe more responsibility to countries downstream) &lt;a href=&quot;https://www.mapsofworld.com/hungary/hungary-river-map.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;(a random example)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Almost all of the water from the northern Pakistani mountains does flow down into central and southern Pakistan and to the Indian Ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Perhaps this fact will be more apparent if the outlines of all the major waterways flowing eventually down into the Indus are shown (from &lt;a href=&quot;http://www.riversnetwork.org/rbo/index.php/river-blogs/central-asia/item/4713&quot; rel=&quot;nofollow noreferrer&quot;&gt;RiversNetwork.org&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8ZMNi.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8ZMNi.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All that area of blue waterways is flowing into the Indus, and down through the country.  These rivers include large gatherings into the Chenab, Sutlej, Zaskar, Nubra, and Shyok, all of which spill into the Indus.  Yes it does include some parts of northern India/Kashmir and eastern Afghanistan.  But note how it also covers almost all of the land in northern Pakistan.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For good measure, this second image, put together from the wealth of tools at &lt;a href=&quot;https://worldmap.harvard.edu/maps/4854&quot; rel=&quot;nofollow noreferrer&quot;&gt;worldmap.harvard.edu&lt;/a&gt;, hints that most water in SE Pakistan also flows into the Indus (the red outline is all areas from which water will flow into the Indus) (Why a discrepancy?  Only guess is maybe SE Pakistan isn't shown on the other map because there's not major waterways in that area?!?!?):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CoaEH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CoaEH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then when you add in the other independent rivers basins in Pakistan like the Dasht, Nal, and Hub:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yKUYW.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yKUYW.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;(Source: &lt;a href=&quot;https://simple.wikipedia.org/wiki/List_of_rivers_of_Pakistan&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rivers of Pakistan on Wikipedia&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;you can see most of the rivers/water out west also stay within the country rather than leaving it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in the end, almost every drop of rain that falls on Pakistan, from the northern mountains, to the deserts, to the heartland, to the Iranian border, all of it already flows further on into Pakistan for use.  In the end, there's only a few tiny slivers of land in the country where water falling on the country is lost by flow to other countries (such as places like near Chaman).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What may be confusing about the image you gave is the gray colors up in the north, nearer the Basha [as well as in southwestern Pakistan].  But those colors aren't showing that water there isn't coming into Pakistan, but only that that area isn't irrigated land.  Basically all the water in those gray areas, like the Pakistani portions of the Hindu-Kush/Himalayas/Karakoam Mountains, flows down into the Indus and through Pakistan.  Plus even more additional water from neighboring countries.  So in other words Pakistan gets more water than what falls on it.  Other countries definitely aren't so lucky.  And that water is already coming down into the rest of the country.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of &lt;em&gt;feeding&lt;/em&gt; the country, irrigation could maybe be expanded a bit... but I believe the problem isn't just the lack of water... but that a lot of the rest of the soil is fairly poor for growing.  The book Pakistan's Soil Resources (&lt;a href=&quot;https://portals.iucn.org/library/sites/library/files/documents/WCS-PK-013.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;available online&lt;/a&gt;) classifies more than 1/4 of the country's soil potential as &quot;Agriculturally unproductive or non-agricultural land&quot; due to wind erosion, salinity, extremely low, etc.&lt;br&gt;&#xA;(Some additional land might be made arable by leeching down salt levels, but I believe it would take long periods of time and great amounts of water.  Soil Quality and Agricultural Sustainability, by Rattan Lal, (&lt;a href=&quot;https://books.google.com/books?id=gyUVt8GphKYC&amp;amp;pg=PA76&amp;amp;lpg=PA76&amp;amp;dq=soil%20types%20pakistan&amp;amp;source=bl&amp;amp;ots=nOFyuH7Igp&amp;amp;sig=yVEbKvVoWzExO4Y16UFCeQOPW1Y&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwjlmbPd09XaAhWHzFMKHRw-B384ChDoAQhaMAc#v=onepage&amp;amp;q=soil%20types%20pakistan&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google Books preview&lt;/a&gt;) looks to include some interesting description of the greater complexities and some longterm potentials of many areas of the world, including Pakistan.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, it sounds like the more urgent concern maybe isn't eating &lt;a href=&quot;https://www.samaa.tv/pakistan/2018/04/water-supply-to-many-parts-of-karachi-suspended/&quot; rel=&quot;nofollow noreferrer&quot;&gt;but drinking&lt;/a&gt;? (disappointingly, I think you'll find that most other parts of the world probably aren't very aware of your problem... I certainly wasn't). &#xA; Unfortunately this problem trend is showing up in many other places, such as &lt;a href=&quot;http://time.com/5103259/cape-town-water-crisis/&quot; rel=&quot;nofollow noreferrer&quot;&gt;well-publicized recent issues in southwestern South Africa&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the end, the primary problem for much of &lt;a href=&quot;https://reliefweb.int/sites/reliefweb.int/files/resources/87097D0CD0E109F6C12577980031CFEC-Map.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pakistan's population&lt;/a&gt; likely doesn't stem from the complete lack of water... but instead from the lack of needed infrastructure, pollution issues, and mismanagement, as &lt;a href=&quot;https://tribune.com.pk/story/1667420/1-pakistan-ranks-third-among-countries-facing-water-shortage/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; alludes to.  These are issues that the entire world does struggle with (such as the troubles in &lt;a href=&quot;https://en.wikipedia.org/wiki/Flint_water_crisis&quot; rel=&quot;nofollow noreferrer&quot;&gt;Flint in the USA&lt;/a&gt;).  There are already some parts of the world there are literally growing concerns of not enough water existing in entire regions to sustain it whatsoever (&lt;a href=&quot;https://www.smithsonianmag.com/science-nature/the-colorado-river-runs-dry-61427169/&quot; rel=&quot;nofollow noreferrer&quot;&gt;such as in the SW US/impacting NW Mexico&lt;/a&gt;)  But if the Indus is flowing steadily down to the ocean through your country (please do indicate if its not, the problem may be more serious then!!), it's not a matter of no water, it's the challenge of detouring enough to areas to meet needs, and keeping it clean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Karachi does look a bit of a challenge area &lt;a href=&quot;https://www.google.com/maps/place/Karachi,+Karachi+City,+Sindh,+Pakistan/@24.8550899,67.184261,10z/data=!4m5!3m4!1s0x3eb33e06651d4bbf:0x9cf92f44555a0c23!8m2!3d24.8607343!4d67.0011364&quot; rel=&quot;nofollow noreferrer&quot;&gt;on a map&lt;/a&gt;.  The good news is it's only 60 miles from the Indus.  Quite a few places source their water from such a distance - some places &lt;a href=&quot;https://en.wikipedia.org/wiki/Los_Angeles_Aqueduct&quot; rel=&quot;nofollow noreferrer&quot;&gt;even do get it from hundreds of miles away, even from the far side of mountain ranges&lt;/a&gt; as you kind of suggested.  But the unique challenge is likely how flat the land is in the south nearer Karachi.  Places like California and Rome can take advantage of elevation to better feed the distant water via gravity.  Karachi on the other hand may require much more pumping to get the water from the Indus, and that might well not be cheap/easy over even distances like 50 miles?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(As noted, It looks like most of the N Pakistani mountains are south of the continental divide, so almost all their water flows your way already. The few miles of snowpack flowing into Tajikistan and such a) may well be needed by their people and b) could be diverted into the Indus with some effort... but that won't solve problems if the Indus is already steadily flowing. The Suleiman Range might offer some options to divert a little more water west of the Indus using tunnels like in the LA Aqueduct... but that would depend a great deal on the specifics of the topography and precipitation levels in those mountains for feasibility.) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, indeed, all that water from your mountains is indeed flowing right through the heart of Pakistan, &quot;right by your window&quot; almost (plus the gift of extra input from areas of far northern India).  It's just getting it from the Indus to where it's needed.  And it just needs to be taken care of carefully.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the end, Pakistan actually has it a lot better water-wise than much of the Arab world.  Find the green:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tsXQC.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tsXQC.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;(&lt;a href=&quot;https://worldview.earthdata.nasa.gov/?p=geographic&amp;amp;l=VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor,Reference_Labels(hidden),Reference_Features,Coastlines&amp;amp;t=2017-09-10-T00%3A00%3A00Z&amp;amp;z=3&amp;amp;v=35.54403661930006,17.33015962977765,91.79403661930006,45.490315879777654&quot; rel=&quot;nofollow noreferrer&quot;&gt;image from NASA MODIS satellite&lt;/a&gt;)&lt;br&gt;&#xA;That spline is the blessing that led to the growth of your country... and its the great challenge of the country today.  &lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-04-26T00:43:48.763" LastActivityDate="2018-04-26T00:43:48.763" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13983" PostTypeId="2" ParentId="13980" CreationDate="2018-04-25T19:26:58.713" Score="3" Body="&lt;p&gt;The continental crust and shelf of new zealand is one peice that has a fault running through it due to it running over a boundary between two oceanic plates. Continental crust cannot really* subduct due to its lower density so if forced onto a subduction zone they will actually slide over it onto the other plate. It helps of you remember oceanic crust and continental crust can exist on the same plate but have different properties. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Something similar has/is happening in &lt;a href=&quot;https://en.wikipedia.org/wiki/San_Andreas_Fault&quot; rel=&quot;nofollow noreferrer&quot;&gt;North America&lt;/a&gt; the san andreas fault is caused by part of the north american continent running over the old east pacific (farallon) plate and spreading center, so now the portion attached to the north american plate is being dragged in one direction and peice sitting on/in the (west) pacific plate is moving in a different one. it is slowly pulling the continent apart and eventually may create an island like new zealand. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://maps.unomaha.edu/maher/plate/week9/transcurrent.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; is more in depth discussion of strike-slip/transcurrent plate boundaries. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jYnkg.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jYnkg.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*small pieces can get dragged down but not much. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2018-04-27T16:52:32.647" LastActivityDate="2018-04-27T16:52:32.647" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13985" PostTypeId="2" ParentId="4514" CreationDate="2018-04-26T02:41:03.953" Score="-2" Body="&lt;p&gt;False! the tsunami caused major upwellings of cold subsurface waters and even slowed, temporarily stopped or shifted some ocean currents. All this led to the drought that plagued the west coast for years, until the Humbolt current resumed it's normal path. Many other recent weather anomalies since 2011 can be blamed on this Tsunami and it's lasting effects.&lt;/p&gt;&#xA;" OwnerUserId="12781" LastActivityDate="2018-04-26T02:41:03.953" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13986" PostTypeId="2" ParentId="13979" CreationDate="2018-04-26T04:56:43.463" Score="1" Body="&lt;p&gt;In response to the question and answer added, i appreciate the the comments that the water drops in Pakistan stays in Pakistan &quot;very strong word&quot; and like that. I will add short answer, if you can track the major rivers of Pakistan, India and Bangladesh, also Yangtze river (Changjiang river) in China, They all mostly originated from Tibetan Plateau (TP), located in southwestern China. This region is called roof of the earth (We can also call it Water Tank of South Asia) with elevated surface and snow cover peaks. TP is source of these major rivers that include all rivers in Pakistan, India and Bangladesh. These rivers in case of Pakistan passes through different regions and make its way to Arabian sea. To serve the inland needs, The British built very sophisticated irrigation system across Pakistan that also includes the Upper and Lower Swat Canal system. &#xA;I think for further details it will be better to go through the following link to see rainfed and irrigated regions, &lt;a href=&quot;https://web.croplands.org/app/map?lat=24.18685&amp;amp;lng=87.45117187500001&amp;amp;zoom=5&quot; rel=&quot;nofollow noreferrer&quot;&gt;Irrigated and Rainfed regions&lt;/a&gt;. Apart from that please refer to recent studies about TP for further details. &lt;/p&gt;&#xA;" OwnerUserId="8158" LastActivityDate="2018-04-26T04:56:43.463" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="13988" PostTypeId="1" AcceptedAnswerId="16354" CreationDate="2018-04-26T10:40:57.630" Score="1" ViewCount="256" Body="&lt;p&gt;This is a layman's question. While looking for something I read in the news today, I stumbled upon the Haean region in South Korea (&lt;a href=&quot;https://www.google.com/maps/place/38%C2%B017&amp;#39;16.0%22N+128%C2%B007&amp;#39;57.2%22E/@38.2877667,127.8545873,96006m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d38.2877667!4d128.13255&quot; rel=&quot;nofollow noreferrer&quot;&gt;38°17'15.96&quot;N, 128° 7'57.18&quot;E&lt;/a&gt;) in Google Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To me it looks either like a caldera or like a meteor impact site. Does anyone know from available facts whether one or the other is true? &lt;a href=&quot;https://en.wikipedia.org/wiki/Haean&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; doesn't say anything about it. Is there any way to tell from the geometric features alone, or does it require taking soil samples from the site?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Interestingly there are some more crater-like features in South Korea (e.g.  &lt;a href=&quot;https://www.google.com/maps/place/37%C2%B049&amp;#39;05.1%22N+127%C2%B003&amp;#39;12.5%22E/@37.8121197,127.0481571,12072m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d37.8180889!4d127.0534806&quot; rel=&quot;nofollow noreferrer&quot;&gt;37°49'5.12&quot;N, 127° 3'12.53&quot;E&lt;/a&gt;, almost perfect circular shape). Can this be considered a result of the proximity of the pacific ring of fire, or is it just too far away?&lt;/p&gt;&#xA;" OwnerUserId="12784" LastEditorUserId="6298" LastEditDate="2018-04-26T20:19:35.410" LastActivityDate="2019-02-28T08:21:42.693" Title="Haean, South Korea: is it of volcanic or meteor impact origin?" Tags="|volcanology|meteorite|impacts|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="13990" PostTypeId="1" CreationDate="2018-04-26T14:04:09.593" Score="11" ViewCount="1479" Body="&lt;p&gt;Today, the oxygen in the atmosphere is about 10&lt;sup&gt;18&lt;/sup&gt; kg.&#xA;The estimated carbon biomass of the earth is about 4×10&lt;sup&gt;15&lt;/sup&gt;. Less than 0.5%.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Estimated fossil fuels are around 5 times as much as existing carbon biomass. If these estimates are appropriate, then probably before the oxygen was released it was not locked up in carbon compounds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oxygen could have been extracted from inorganic stuff and cycled through the biomass. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which reduced minerals were left behind? Not silicates and carbonates. Little magnetite crystals? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe there was more SiO&lt;sub&gt;4&lt;/sub&gt; before (things like olivine), and living things tended to produce silicates with less oxygen (things like kaolin)? There isn't a whole lot of silica dissolved in seawater at any one time, but there's a whole lot of silica available and it could add up eventually. Silicates with more oxygen weathered away, and silicates with less oxygen were deposited?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe there's so much free oxygen &lt;em&gt;today&lt;/em&gt; because some H&lt;sub&gt;2&lt;/sub&gt; got produced, and it rose right out of the atmosphere and got swept away. So there's less water and more oxygen than there used to be.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe the biomass estimates, and the fossil fuel estimates, don't actually tell us about the carbon, and there is lots of reduced carbon elsewhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm speculating, does anybody have good answers?&lt;/p&gt;&#xA;" OwnerUserId="12787" LastEditorUserId="725" LastEditDate="2018-04-28T09:38:03.423" LastActivityDate="2023-07-12T09:50:27.307" Title="Before the Great Oxygenation Event, where was the oxygen?" Tags="|earth-history|biogeochemistry|great-oxidation-event|" AnswerCount="6" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13991" PostTypeId="2" ParentId="13990" CreationDate="2018-04-26T16:30:25.893" Score="5" Body="&lt;p&gt;the great oxygenation event was caused by the evolution of photosynthesis, photosynthesis turns CO2 and water in to sugar and oxygen. so the oxygen came from CO2 and water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;keep in mind CO2 levels were many many times higher (~20X) than today. Hydrogen was not released it was combined with carbon and oxygen to make sugars &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7Tmp7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7Tmp7.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2018-04-27T21:41:39.843" LastActivityDate="2018-04-27T21:41:39.843" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="13992" PostTypeId="1" CreationDate="2018-04-26T16:54:49.573" Score="2" ViewCount="1249" Body="&lt;p&gt;The general idea that has been taught to people is that there is an imaginary axis that crosses the earth from the north pole to the south pole (or vice versa).And that is the axis of rotation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I have always thought that idea is not so accurate and that there are other poles that are the true and the geographics don't coincide with the true poles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I am correct with that idea, I can affirm that there is also a true equatorial line that doesn't coincide with the geographical equatorial line.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Am I right?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[Update]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I asked that question because I live in Ecuador and here there is a commemorative monument of the French geodesic mission (between 1736 and 1744) and besides being a tourist center in which visitors are shown experiments as a container full of water with a siphon in which no swirl occurs because they are in exactly the equatorial line, in addition to other tricks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here you can see a video of different experiments:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.facebook.com/nasdaily/videos/923542644464555/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.facebook.com/nasdaily/videos/923542644464555/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have reasoned and I think that the effects caused by being on the equatorial line would happen if the axis of the earth did not have wobbles and according to what it says here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Equator&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Equator&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Precise location&#xA;The precise location of the Equator is not truly fixed; the true equatorial plane is perpendicular to the Earth's spin axis, which drifts about 9 metres (30 ft) during a year. This effect must be accounted for in detailed geophysical measurements&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then the true equatorial line would change in a range of +/- 9 meters each year and the effects shown to tourists on the equatorial line may have been for the following reasons:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;They are false tricks since the effects of the equatorial line move throughout the year in an area of ​​approximately 9 meters and for such &quot;experiments&quot; to happen they should move the devices to find the effects of the equatorial line constantly throughout the year.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The tricks are true, but they do not happen exactly on the geographical equatorial line, but within a range of 9 meters.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="12790" LastEditorUserId="12790" LastEditDate="2018-04-28T19:31:48.473" LastActivityDate="2018-08-26T22:01:23.570" Title="The axis of rotation of the earth passes through the geographical poles or is there a true axis?" Tags="|poles|" AnswerCount="2" CommentCount="5" FavoriteCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13993" PostTypeId="1" CreationDate="2018-04-26T20:16:56.970" Score="1" ViewCount="238" Body="&lt;p&gt;Well it seems like the coldest month in the western US should be February since it's closer to oceans than interior areas of the continent. This is called seasonal lag. It's a phenomenon where the shortest day of the year (Dec 21 in northern hemisphere) is NOT the coldest, which is mainly dependent on proximity to oceans. Interior areas typically are coldest in late December and early January while coastal areas are later. This doesn't seem to be the case for the west coast in the US. Why?&lt;/p&gt;&#xA;" OwnerUserId="6916" LastActivityDate="2018-04-26T20:16:56.970" Title="Why is December colder than January in the western United States?" Tags="|climate|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13995" PostTypeId="1" CreationDate="2018-04-26T21:28:55.190" Score="5" ViewCount="393" Body="&lt;p&gt;So I found a map of the US that shows the number of partly cloudy days in different areas of the country. It seems that Florida is the only state with more partly cloudy days. Partly cloudy days are when the sky is not clear but not overcast. I think it's odd that Colorado has few days of clear skies yet few days of overcast skies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.eldoradocountyweather.com/climate/US%20Climate%20Maps/images/Lower%2048%20States/Sky%20Cover%20-%20Visibility/Mean%20Number%20of%20Partly%20Cloudy%20Days%20Sunrise%20to%20Sunrise/Annual%20Mean%20Number%20of%20Partly%20Cloudy%20Days%20Sunrise%20to%20Sunset.png&quot; rel=&quot;noreferrer&quot;&gt;http://www.eldoradocountyweather.com/climate/US%20Climate%20Maps/images/Lower%2048%20States/Sky%20Cover%20-%20Visibility/Mean%20Number%20of%20Partly%20Cloudy%20Days%20Sunrise%20to%20Sunrise/Annual%20Mean%20Number%20of%20Partly%20Cloudy%20Days%20Sunrise%20to%20Sunset.png&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6916" LastActivityDate="2019-12-25T05:07:32.297" Title="Why does Colorado have so many days of partly cloudy skies?" Tags="|climate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13996" PostTypeId="1" AcceptedAnswerId="14004" CreationDate="2018-04-26T22:19:29.900" Score="6" ViewCount="140" Body="&lt;p&gt;These pictures were taken today in Oklahoma City and I am both baffled and curious as to what formation this may be. I was wondering if anyone had any idea?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zI74D.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zI74D.jpg&quot; alt=&quot;unknown cloud 1&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3mtUD.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3mtUD.jpg&quot; alt=&quot;unknown cloud 2&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;" OwnerUserId="6506" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T08:58:34.313" LastActivityDate="2019-08-28T08:58:34.313" Title="Can someone help me identify this cloud formation?" Tags="|meteorology|clouds|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="13998" PostTypeId="2" ParentId="13995" CreationDate="2018-04-27T02:30:24.427" Score="7" Body="&lt;p&gt;I'd personally theorize the main answer is mountains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thinking the key is localized &quot;mesoscale&quot; features that disrupt large-scale patterns.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Florida, it's the surrounding oceans that generate daytime seabreeze storms in the summer and provide moisture return (and thus clouds) more quickly after frontal passages in the winter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Colorado, would think it's the mountainous terrain causing circulations like the &lt;a href=&quot;https://en.wikipedia.org/wiki/Denver_Convergence_Vorticity_Zone&quot; rel=&quot;nofollow noreferrer&quot;&gt;Denver Cyclone&lt;/a&gt; creating daytime clouds in the summer, and vertical motion that may well disrupt some of the foggy, stable winter days.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some mesoscale influences create almost continual cloudiness, such as the cold oceans along the US Pacific Coast.  Others remove more cloudiness, like the terrain and resulting deserts in much of the US Southwest.  For more in-depth details on cloudcoverage, including annual and monthly totals maps, see &lt;a href=&quot;http://us-climate.blogspot.com/2015/03/average-cloudiness.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this us-climate.blogspot.com article&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But one key aspect of both the Florida seabreeze and mountainous circulations is that they are &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Diurnal&quot; rel=&quot;nofollow noreferrer&quot;&gt;diurnal&lt;/a&gt;.  So, often, whatever they bring in one part of the day, they generate the opposite at the other end of the day.  For more about how mountain winds vary through the day, look into &lt;a href=&quot;https://en.wikipedia.org/wiki/Mountain_breeze_and_valley_breeze&quot; rel=&quot;nofollow noreferrer&quot;&gt;mountain and valley breezes&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd also suggest the greatest proportion of cloudiest (foggiest) days in the US are winter periods where cold air is in place under a high pressure and moisture builds up within the stable conditions.  Being elevated in Colorado may additionally aid prevention of some such days by having lower moisture depth and also by being more exposed to winds [while Florida instead is less often deeply entrenched in cold airmasses].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just thoughts, but hopefully that offers some direction for why it may be!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-04-27T10:45:36.040" LastActivityDate="2018-04-27T10:45:36.040" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="13999" PostTypeId="2" ParentId="13992" CreationDate="2018-04-27T07:33:36.873" Score="1" Body="&lt;p&gt;&lt;strong&gt;Geographic axis is NOT fixed.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;North and south poles are NOT fixed.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ideology is reverse of what you are thinking. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;First suppose that Earth is rotating about some arbitrary axis =&gt; Then this axis intersects on Earth's surface at two points =&gt; Now, if you see earth from above and observe earth rotating in counter-clockwise direction then this point is &lt;em&gt;defined&lt;/em&gt; as North pole and hence other will be south pole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;In short, first we see earth rotating about an axis and then north and south poles are defined according to it.&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, the axis of rotation &lt;em&gt;wobbles&lt;/em&gt; and as a result north and south pole wanders a bit. This is known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Chandler_wobble&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chandler wobble&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Note: It is very important to realize that according to chandler wobble axis of rotation wobbles with respect to Earth. Earth itself is NOT wobbling due to chandler wobble, it is only changing the axis of rotation.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;So, there is no concept of true axis here, but only one axis -&gt; geographic axis which wobbles.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="11861" LastEditorUserId="11861" LastEditDate="2018-04-28T20:01:06.403" LastActivityDate="2018-04-28T20:01:06.403" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="14000" PostTypeId="2" ParentId="13990" CreationDate="2018-04-27T09:15:34.633" Score="1" Body="&lt;p&gt;Actually quite interesting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oxygen is made by the splitting of water, either by photosynthesis or by UV-based photo-dissociation in the upper atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case of photosynthesis, the reduced-carbon products must be buried in order for a net accumulation of oxygen to happen. In this case the oxygen effectively comes from water:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1) 2H2O + vis. light. -&gt; 2H2 + O2   (Water to hydrogen and oxygen)&#xA;(2) 2H2 + CO2 -&gt; H2CO + H2O (Carbon dioxide and Hydrogen to carbohydrate and water. Carbohydrate is buried)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And from UV-dissociation, we get&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1) 2H2O + uv -&gt; 2H2 + O2   (Water to hydrogen and oxygen, hydrogen is lost to space)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The oceans weight over 10^21kg, most of which is oxygen, so there is plenty of mass there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://science.sciencemag.org/content/293/5531/839?ck=nck&quot; rel=&quot;nofollow noreferrer&quot;&gt;Methane Photodissociation&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reaction is effectively (in an oxygen free atmosphere):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(3) CH4 + 2H2O + uv -&gt; CO2 + 4H2 (lost to space)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that without hydrogen loss to space, there is a limit on the amount of oxygenation that can happen, because the reduced carbon generated in photosynthesis has to be buried geologically.  Estimates for the amount of buried reduced carbon are hard to find (carbonates don't count for this purpose).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the ultimate source of oxygen in the atmosphere would appear to be water, mostly.&lt;/p&gt;&#xA;" OwnerUserId="8217" LastEditorUserId="8217" LastEditDate="2018-04-30T12:47:38.243" LastActivityDate="2018-04-30T12:47:38.243" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="14001" PostTypeId="1" CreationDate="2018-04-27T10:36:36.783" Score="1" ViewCount="66" Body="&lt;p&gt;I live in the Middle East and I am really fond of understanding meteorology and using raw data make my own weather predictions. However, a limitation I encounter here is that most raw meteorological data providers e.g. radars are only limited to the US or UK. I would like to know if there are any sources that provide professional raw weather data for the Middle East. Thank you a lot.&lt;/p&gt;&#xA;" OwnerUserId="12795" LastActivityDate="2018-04-27T14:21:35.933" Title="Where can I get good raw meteorological data for Middle East?" Tags="|meteorology|weather-forecasting|weather-satellites|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="14003" PostTypeId="1" CreationDate="2018-04-27T12:59:22.573" Score="4" ViewCount="76" Body="&lt;p&gt;Flying east is faster so I expect that if the destination are on opposite points or closer, that the flights between them always be to the east.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example Los Angeles to Delhi. I see the fly is over the north pole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wouldn't it be faster to always go east?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.gcmap.com/mapui?P=lax-del&amp;amp;DU=mi&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.gcmap.com/mapui?P=lax-del&amp;amp;DU=mi&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12797" LastEditorUserId="725" LastEditDate="2018-04-28T09:38:34.633" LastActivityDate="2018-04-28T09:38:34.633" Title="Are there any flights that fly east both from origin to destination and from destination to origin?" Tags="|atmosphere|jet-stream|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="14004" PostTypeId="2" ParentId="13996" CreationDate="2018-04-27T13:15:48.397" Score="1" Body="&lt;p&gt;Well, after a bit of research, I stumbled upon the following image:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vC3cJ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vC3cJ.jpg&quot; alt=&quot;copyright Roger Edwards&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is from a blog of two storm chasers Roger and Elke who I believe witnessed the same cloud formation as you. In the following link:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;http://stormeyes.org/latest/tag/left-moving-supercell/&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;They refer to the formation as a 'rear flank arc cloud'.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in conclusion I believe, the formation is &lt;strong&gt;a kind of arcus cloud&lt;/strong&gt;. You can learn more about arcus clouds on wikipedia by following the link: &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;https://en.wikipedia.org/wiki/Arcus_cloud&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;I hope I have been of help.&lt;/p&gt;&#xA;" OwnerUserId="12795" LastEditorUserId="12795" LastEditDate="2018-05-28T19:24:22.697" LastActivityDate="2018-05-28T19:24:22.697" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14005" PostTypeId="2" ParentId="14001" CreationDate="2018-04-27T14:21:35.933" Score="1" Body="&lt;p&gt;This &lt;a href=&quot;https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/gdj3.12&quot; rel=&quot;nofollow noreferrer&quot;&gt;work&lt;/a&gt; intend to consolidate climate data series from 79 stations in North Africa and the Middle East, between the 19th century to present day. Distribution of the stations are shown in Figure 1:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NvsQ7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NvsQ7.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One challenge they had was an amount of incomplete records in the available dataset during that studied lapse. Table 1 and 2 show the name and location of the sources for the datasets, which could be useful for you to get started if your research need recent (2008-2018) records&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further they provided as supplemental material their raw datasets used in their research &lt;a href=&quot;https://zenodo.org/record/7531&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, as used in their paper (-&gt; 2008).&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2018-04-27T14:21:35.933" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="14007" PostTypeId="1" AcceptedAnswerId="14017" CreationDate="2018-04-27T15:22:26.983" Score="2" ViewCount="1032" Body="&lt;p&gt;I am having massive confusion on whether &lt;strong&gt;intraplate volcanism&lt;/strong&gt; refers to volcanism occurring at &lt;strong&gt;plate boundaries&lt;/strong&gt; or away from &lt;strong&gt;plate boundaries&lt;/strong&gt; (such as formation of &lt;strong&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Ocean_island_basalt&quot; rel=&quot;nofollow noreferrer&quot;&gt;ocean island basalts&lt;/a&gt;&lt;/strong&gt;), or perhaps both?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, are &lt;strong&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Ocean_island_basalt&quot; rel=&quot;nofollow noreferrer&quot;&gt;mid-oceanic ridges&lt;/a&gt;&lt;/strong&gt; related to &lt;strong&gt;intraplate volcanism&lt;/strong&gt;?&lt;/p&gt;&#xA;" OwnerUserId="12718" LastEditorUserId="6298" LastEditDate="2018-04-29T05:59:14.873" LastActivityDate="2018-04-29T09:39:39.273" Title="What is meant by intraplate volcanism?" Tags="|rocks|petrology|igneous|volcanic-eruption|ocean-ridge|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="14010" PostTypeId="2" ParentId="13992" CreationDate="2018-04-27T19:40:16.160" Score="1" Body="&lt;p&gt;Perhaps you are thinking about the discrepancy between true north and magnetic north. The former is where the earth's axis of rotation intersects the earth's surface in the northern hemisphere. The latter is the location where the magnetic field lines of the earth are vertical, meaning a magnetic compass will point to this location. If you follow your compass to the magnetic north pole, you will be roughly 500km from the true north pole which lies on the earth's rotational axis.&lt;/p&gt;&#xA;" OwnerUserId="4971" LastActivityDate="2018-04-27T19:40:16.160" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="14011" PostTypeId="2" ParentId="14007" CreationDate="2018-04-27T20:13:22.427" Score="2" Body="&lt;p&gt;&lt;a href=&quot;http://www.dictionary.com/browse/intra&quot; rel=&quot;nofollow noreferrer&quot;&gt;Intra = within/on the inside&lt;/a&gt;, so intraplate volcanism would be volcanism happening far from plate boundaries, usually hotspots.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have trouble remembering intra- vs inter- remember international trade = trade from one nation to others, domestic trade would be intra-national trade even though no one uses that term. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="6298" LastEditDate="2018-04-29T06:03:33.167" LastActivityDate="2018-04-29T06:03:33.167" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="14012" PostTypeId="2" ParentId="14007" CreationDate="2018-04-27T20:40:10.883" Score="5" Body="&lt;p&gt;&lt;strong&gt;Terms&lt;/strong&gt;:&lt;br&gt;&#xA;Intraplate volcanism - as the name suggests it is volcanism within the plates rather than at plate boundaries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are also known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Hotspot_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;hotspots&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ocean island basalt (OIB) - is the basaltic rocks associated with intraplate volcanism.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Relation between mid-ocean ridges and hotspots&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hotspot–ridge interaction produces a wide range of phenomena including excess crustal thickness, geochemical anomalies, off-axis&#xA;volcanic ridges, and ridge relocations or jumps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For further study refer to this &lt;a href=&quot;https://www.soest.hawaii.edu/GG/FACULTY/ITO/Reprints/Mittelstaedt_etal_EPLS08.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;research paper&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A conceptual schematic of a ridge jump from that paper:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PaKTc.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PaKTc.png&quot; alt=&quot;https://www.soest.hawaii.edu/GG/FACULTY/ITO/Reprints/Mittelstaedt_etal_EPLS08.pdf&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iCTQE.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iCTQE.png&quot; alt=&quot;http://www.nongnu.org/magellan/magellan_ridgejump.html&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.nongnu.org/magellan/magellan_ridgejump.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image Source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;DR: Dying rift&lt;br&gt;&#xA;PR: Propagating rift  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a ridge jump towards the hotspot.  Due to the ridge jump lithosphere from plate B is transfered to plate A.&lt;/p&gt;&#xA;" OwnerUserId="11861" LastEditorUserId="11861" LastEditDate="2018-04-29T09:39:39.273" LastActivityDate="2018-04-29T09:39:39.273" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="14014" PostTypeId="2" ParentId="14003" CreationDate="2018-04-28T07:31:29.650" Score="4" Body="&lt;p&gt;&lt;a href=&quot;https://flightaware.com/live/findflight?origin=KLAX&amp;amp;destination=VIDP&quot; rel=&quot;nofollow noreferrer&quot;&gt;FlightAware suggests there are no non-stop flights from LA to Delhi&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Was certainly going to point out that we're pretty limited on &lt;a href=&quot;https://en.wikipedia.org/wiki/Ultra_long-haul&quot; rel=&quot;nofollow noreferrer&quot;&gt;ultra long-haul flights&lt;/a&gt; still, and it'd take a very special flight setup to make your scenario.  You'd need both:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Two locations about 180° longitude apart so that the distance going east vs. the distance going west is insignificant for both legs enough so the &lt;a href=&quot;https://en.wikipedia.org/wiki/Jet_stream&quot; rel=&quot;nofollow noreferrer&quot;&gt;jet stream&lt;/a&gt; gains flying east pay off.&lt;/li&gt;&#xA;&lt;li&gt;Two places at just the right latitudes.  They need to be at latitudes far enough south (in the NH) that it's not much shorter to just fly the great circle through the North Pole [or near if not 180° apart].&lt;br&gt;&#xA;&lt;a href=&quot;https://www.desmos.com/calculator/g2bvwufewp&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here is a graph&lt;/a&gt; showing the ratio of the distances of the path crossing the Pole vs the distance of the constant-latitude path, for places 180° longitude apart [derivation in comments]... which shows it's 50% longer to fly around the 60° latitude circle than to fly over the Pole).&lt;br&gt;&#xA;However, the further equatorward (south in the NH) you go, the less benefit you'd get from the jet stream as upper wind speeds are typically much slower further south, and you'd spend less of your flight time in the jet stream.  (&lt;a href=&quot;http://www.pivotalweather.com/model.php?m=gfs&amp;amp;p=300wh_nb&amp;amp;rh=2018042800&amp;amp;fh=loop&amp;amp;r=nh&amp;amp;dpdt=&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's a current jet stream map&lt;/a&gt;).  &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Keep in mind that the jet stream is only going to add 100-200 mph in general.  So that's only like 1/3 of the &lt;a href=&quot;https://www.google.com/search?client=opera&amp;amp;q=a380%20cruising%20speed&amp;amp;sourceid=opera&amp;amp;ie=UTF-8&amp;amp;oe=UTF-8&quot; rel=&quot;nofollow noreferrer&quot;&gt;cruising speed of a large jet&lt;/a&gt;.  Of course the benefits will show up in both in fuel usage (and the additional weight benefits of carrying less fuel) and in travel time (people like quicker flights, and you can run more flights in a year and/or pay crew less).  So despite being a longer distance, if it cut enough time/energy it might just be worth it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And, well go figure, it turns out you weren't far off at all!  Because there actually is a direct flight from San Francisco to Delhi.  And it looks like they do exactly as you suggested!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cjJ2s.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cjJ2sm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/kLM4c.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kLM4cm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;(Click images for larger versions)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are Air India flights &lt;a href=&quot;https://flightaware.com/live/flight/AIC173&quot; rel=&quot;nofollow noreferrer&quot;&gt;173&lt;/a&gt; and &lt;a href=&quot;https://flightaware.com/live/flight/AIC174&quot; rel=&quot;nofollow noreferrer&quot;&gt;174&lt;/a&gt;.  The official flight does make a jaunt from Delhi to Bengaluru and back once it completes the SFO-DEL leg.  But you could indeed go around the world from Delhi to San Francisco to Delhi without any other stops... in looks like around 36 hours.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pretty cool!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-04-28T09:30:56.297" LastActivityDate="2018-04-28T09:30:56.297" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="14015" PostTypeId="2" ParentId="13959" CreationDate="2018-04-28T07:58:45.330" Score="4" Body="&lt;p&gt;Short answer  (this is essentially what the paragraph is saying):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;55.5 to 33.9 million years ago (&quot;mya&quot; or &quot;ma&quot;) the Earth cooled (Eocene period)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;33.9 to 33.5 mya: temporary cooling minimum, glaciers form, sea level falls. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;32.5 to 25.5 mya: cooling trend has come to an end.  &quot;Stepwise climate change&quot;, carefully measured, note the line-chart has more detail and variation in this range compared to before.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;26 to 28 mya, huge volcanic eruption that lead to 2 million years of temporary warming.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;23.03 to 22.6 mya, end of the Oglicene, cooling trend returns, some glaciation.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The wikipedia article fails to tie those various ideas from studies together with any finesse at all.  I did it using bullet points.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I had a chat with a professor friend of mine.   Basically &quot;stepwise&quot; means, you ignore the statistical noise and work the numbers down from a bunch of scattered points into a neat single line.   It's usually called &lt;a href=&quot;https://en.wikipedia.org/wiki/Stepwise_regression&quot; rel=&quot;nofollow noreferrer&quot;&gt;stepwise regression&lt;/a&gt; or sometimes, stepwise modeling.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Stepwise climate change&quot; basically means: 'using a stepwise regression model on global climate temperature estimates &lt;a href=&quot;https://earthobservatory.nasa.gov/Features/Paleoclimatology_OxygenBalance/&quot; rel=&quot;nofollow noreferrer&quot;&gt;based on Oxygen 18 concentration&lt;/a&gt; in dated sediment&quot;.  That's clear enough to anyone who speaks the language but &quot;stepwise climate change&quot; is unclear to most of us and Wikipedia probably shouldn't use the term without explaining it.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Longer answer:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Stepwise models are useful for visualizing information but they oversimplify and can be flawed.   Earth's Milankovich cycles during ice-age epochs (like the one we're in today) can fluctuate Earth's average global temperature by as much as 4-5 degrees Celsius due to significant changes in albedo as a result of significant variation in ice-cover and other factors.   During non ice-age periods, that variation is less, but there's still natural variation of perhaps 1-2 or 3 degrees which occurs every 40,000 to 100,000 years or so, depending in part on the location of the continents, shape of the oceans and whether or not glaciers and sea ice can form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's difficult to pinpoint and incorporate 40,000 - 100,000 year cycles into a model that shows 66 million years of global temperature history, especially when the margin of error for dating is as large or larger than the orbital periods.   The stepwise reduction approach is useful in that it simplifies average global temperature into a neat and tidy line that filters out variations and in a sense, averages out any effect from orbital cycles.   We could barely see 40,000 years on a 66 million year chart anyway and trying to work in 10-25 orbital variations per million years would be extremely difficult.  The stepwise approach produces a nice and neat line graph as opposed to a scatter plot. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The Paleogene&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Paleogene&quot; rel=&quot;nofollow noreferrer&quot;&gt;Paleo&lt;strong&gt;g&lt;/strong&gt;ene period&lt;/a&gt; (23.03 to 66 mya), can be broken up into 3 segments, the Paleo&lt;strong&gt;c&lt;/strong&gt;ene, the Eocene and the Ogliocene.  The first 11 million years of the Paleogene &lt;a href=&quot;https://en.wikipedia.org/wiki/Oligocene#/media/File:All_palaeotemps.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;experienced a warming trend&lt;/a&gt;, so when the article talks about the Paleogene cooling, they're talking about 55.5 to 33 mya.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Paleocene (55.5 to 66 mya), Earth got hotter, peaking as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Paleocene%E2%80%93Eocene_Thermal_Maximum&quot; rel=&quot;nofollow noreferrer&quot;&gt;Paleogene-Eocene thermal maximum&lt;/a&gt;, sometimes abbreviated PETM, which peaked at about 12 degrees C warmer than 20th century average temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Eocene (which the paragraph unnecessarily calls the Paleogene general temperature decline), 55.5 to 33.9 mya, was, needless to say, a period where the Earth cooled.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Ogliocene, 33.9 to 23.03 mya, was, loosely speaking, the end of that cooling trend.  (It was obviously much more than just that, but I'm interpreting from the initial paragraph in the question)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Breaking down the paragraph&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Paleogene Period general temperature decline is interrupted by an&#xA;  Oligocene 7-million-year stepwise climate change.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A deeper 8.2°C, 400,000-year temperature depression leads the 2°C,&#xA;  seven-million-year stepwise climate change 33.5 Ma (million years&#xA;  ago).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A number of other articles, &lt;a href=&quot;https://en.wikipedia.org/wiki/Oligocene&quot; rel=&quot;nofollow noreferrer&quot;&gt;including Wikipedia&lt;/a&gt; give the start of the Ogliocene as 33.9 mya.   And if we take 400,000 years preceeding from the 33.5 mya mentioned in the paragraph, that works out nicely to 33.9 mya.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The paragraph seems to be saying that there was an 8.2 degree drop culminating in the period 33.9 and 33.5 mya.  Presumably that drop is from the peak temperature at PETM.   And following that 400,000 year period of colder temperature at the start of the Ogliocene.  Then there was a 2 degree (warming?), or 2 degree variation, beginning around 33.5 mya.  The article mentions 2 degrees and implies but doesn't specifically say that it was 2 degrees of warming.   The line-chart shows a slight upward trend and some variation following the initial drop 33.9 to 33.5 mya.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The stepwise climate change began 32.5 Ma and lasted through to 25.5&#xA;  Ma, as depicted in the PaleoTemps chart&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This bit is confusing, because just above they mentioned 7 million year &quot;stepwise climate change&quot; and 33.5 mya in the same sentence.  Here they define the 7 million years as beginning at 32.5 mya.   They skipped over a million years without explanation and specifically identify 32.5 to 25.5 mya as the 7 million years of stepwise climate change.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Oligocene climate change was a global increase in ice volume and a&#xA;  55 m (181 feet) decrease in sea level (35.7–33.5 Ma) . . . &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This line is fine.  It indicates that during the 400,000 year cold period (presumably 33.9 to 33.5 mya), ice formed and sea levels fell, a total of 55 meters compared to 2.2 million years earlier, when, presumably, there was little or no glacial ice.    Comparing sea level to a seemingly random date 2.2 million years before is fine.  There's nothing wrong with picking an earlier date for comparison.  (so long as it's not cherry-picked).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;. . . with a closely related (25.5–32.5 Ma) temperature depression.&#xA;  The 7-million-year depression abruptly terminated within 1–2 million&#xA;  years of the La Garita Caldera eruption at 28–26 Ma&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Again, the article just skips a million years to 32.5 and here it mentions a &lt;em&gt;temperature depression&lt;/em&gt;, and I'm going to pull the first sentence up here:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Paleogene Period general temperature decline is interrupted by an&#xA;  Oligocene 7-million-year stepwise climate change.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is very confusing, because the paragraph mentions the temperature decline being interrupted, then, a little later, it calls that same period a &quot;temperature depression&quot;.   That's unclear to the point where I want to say it's a writing error.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &quot;the La Garita Caldera eruption&quot; part is fine, which ended the so called &quot;temperature depression&quot; and warmed the Earth up a little.  Now, if you look at the line chart, between 33.9 and 28 (give or take), it was colder and then it was warmer before 33.9 and warmer (briefly) after 28, so technically, that is a depression, but it's still very poorly explained.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Volcanic eruptions initially make the Earth colder due to ash blocking sunlight, but in the long run, very rare, super volcanic eruptions can cover parts of the Earth and glaciers with ash, darkening it and leading to less energy lost by reflection and leading to glacial melt.  The blocked sun can kill plants as well, and if the volcano is large enough, it release significant amounts of CO2 as well, which, after the initial significant cooling (as the Ash in the air is quite temporary), very large volcanoes can trigger a longer lasting warming period due to increased CO2.  It's reasonable and certainly possible that a sufficiently large volcano could do that, and that's what the paragraph seems to be implying.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally the article mentions&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A deep 400,000-year glaciated Oligocene Miocene boundary event is&#xA;  recorded at McMurdo Sound and King George Island.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, there was a glaciation as the Ogliocene ended and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Miocene&quot; rel=&quot;nofollow noreferrer&quot;&gt;Miocene (23.03 to 5.333 mya)&lt;/a&gt; began.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;What this seems to be is a very poorly constructed combination of various studies, one study appears to be a 7 million year stepwise reconstruction of climate, between 25.5 and 32.5 mya.   That study may be excellent, but the writer of the wikipedia article was too lazy to bridge the open spaces between various research reports into a coherant series of paragraphs.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In defense of the Wikipedia writer, pretty much every statement is followed by a reference, so if you read the references, it probably makes a lot more sense.  It's just very poorly constructed as a paragraph read on it's own, which is how nearly everybody who checks the page will read it.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2018-04-28T08:20:04.500" LastActivityDate="2018-04-28T08:20:04.500" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="14016" PostTypeId="2" ParentId="13990" CreationDate="2018-04-28T09:55:01.517" Score="4" Body="&lt;p&gt;I'd like to add to the other answers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, it is correct that photosynthesis by cyanobacteria caused the rise of atmospheric oxygen. Some important points to talk about:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Estimated fossil fuels are around 5 times as much as existing carbon biomass. If these estimates are appropriate, then probably before the oxygen was released it was not locked up in carbon compounds.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Fossil fuels are irrelevant to the discussion. Fossil fuels only started forming in the Phanerozoic, about 500 million years ago. The rise of oxygen occurred more than 2 billion years ago.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Oxygen could have been extracted from inorganic stuff and cycled through the biomass.&#xA;  Which reduced minerals were left behind? Not silicates and carbonates. Little magnetite crystals? &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Nothing, actually. The minerals found on the surface of the Earth formed as a response to the presence of atmospheric oxygen. This means that oxidised minerals on the surface only appeared after we had atmospheric oxygen. This means that something else had to be reduced. For example, sedimentary detrital pyrite was a &lt;a href=&quot;https://en.wikipedia.org/wiki/Witwatersrand&quot; rel=&quot;nofollow noreferrer&quot;&gt;thing&lt;/a&gt;! Not possible today with the presence of oxygen.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Maybe there was more SiO4 before (things like olivine), and living things tended to produce silicates with less oxygen (things like kaolin)? &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not accurate. Both olivine and kaolinite are stable over a very wide oxidation states. Doing the charge-balance math shows that the silica exists as Si&lt;sup&gt;4+&lt;/sup&gt; in all silicates. If anything, olivine is a reduced formed (it has Fe&lt;sup&gt;2+&lt;/sup&gt;) and is not stable on the surface as it oxidises (&quot;rusts&quot;).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Silicates with more oxygen weathered away, and silicates with less oxygen were deposited?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not really.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The key point is that the oxygen came from photosynthesis, and reduction of H&lt;sub&gt;2&lt;/sub&gt;O and CO&lt;sub&gt;2&lt;/sub&gt; to form organic matter. Carbon and hydrogen form the organic stuff, and the leftover O&lt;sub&gt;2&lt;/sub&gt; is emitted to the atmosphere. But do we have enough carbon? You say:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;was there that much CO2 before? Oxygen is supposedly the most common element in the earth's crust, about 466 parts per thousand by weight.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But, most of the oxygen is locked up in minerals and is completely irrelevant for this discussion as it does not participate in the reactions. Carbon is being constantly emitted by volcanism. It is then consumed by either mineral carbonation reactions (such as formation of olivine to magnesite: magnesium carbonate) on the surface, or by formation of organic matter. Therefore, CO&lt;sub&gt;2&lt;/sub&gt; doesn't have the chance to accumulate in the atmosphere. However, oxygen isn't consumed by reactions, so it accumulates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the beginning, oxygen didn't actually accumulate. It also had a sink: dissolved Fe&lt;sup&gt;2+&lt;/sup&gt; in the oceans. Oxidation of that iron caused formation of insoluble Fe&lt;sup&gt;3+&lt;/sup&gt; oxides and hydroxides, which we see today as &lt;a href=&quot;https://en.wikipedia.org/wiki/Banded_iron_formation&quot; rel=&quot;nofollow noreferrer&quot;&gt;banded iron formations&lt;/a&gt;. Only once the iron was consumed, the oxygen could start accumulating in the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-04-28T09:55:01.517" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="14017" PostTypeId="2" ParentId="14007" CreationDate="2018-04-28T10:03:11.323" Score="5" Body="&lt;p&gt;The majority of Earth's volcanoes occur in plate boundaries. These can be at spreading ridges (green dots on the map) where they are mostly underwater, but sometimes are above the water (such as in Iceland). They can also be on convergent margins, for example the Pacific ring of fire.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A less common type of volcano is the intraplate volcano, which are basically all volcanoes not in plate margins because that are inside (=&quot;intra&quot;) a plate. Hawaii is probably the most famous example, together with the abundant seamounts elsewhere in the Pacific. They are usually formed by deeper processes, with mantle plumes coming from below the lithosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1Sizn.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1Sizn.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-04-28T10:03:11.323" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="14019" PostTypeId="1" CreationDate="2018-04-28T12:55:21.973" Score="3" ViewCount="58" Body="&lt;p&gt;Atmospheric metals usually reside in aerosols with complex source origins. The concentrations distribution of metals especially for those with high toxicity (Pb, Cd, Ni, V) should be informative for assessing the health effects.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source apportionment studies can link the atmospheric species with source emissions, and the results can support the policy designing for pollution control. Therefore, to determine the pollution levels of heavy metals and quantify their origins should be an essential part for health risk management.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Usually, the source apportionment include three different methods, i.e., inventories-based, chemical transport model-based and  receptor-based. For those studies for identifying the source origins of atmospheric metals, receptor models were the dominant method, and CTM models were seldom adopted. Therefore, I want to ask the difficulties of simulating atmospheric metals in different aspects.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I come up with one reason:    &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The source origins of atmospheric were complex with anthropogenic, and natural sources all affected. Therefore, building the source inventories for those metals were challenging. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Is there any other issues counted in the simulation work. Any comments or recommended material would be highly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="5214" LastActivityDate="2018-04-28T12:55:21.973" Title="The difficulties for the simulation of atmospheric metals" Tags="|models|atmosphere-modelling|air-pollution|atmospheric-chemistry|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 3.0" />
  <row Id="14020" PostTypeId="1" CreationDate="2018-04-28T13:47:12.720" Score="4" ViewCount="583" Body="&lt;p&gt;I was wondering since UV index is higher as elevation increases, is the brightness of the sun changing as elevation increases?&lt;/p&gt;&#xA;" OwnerUserId="6916" LastActivityDate="2018-04-28T13:47:12.720" Title="Is the sun brighter at higher altitudes?" Tags="|mountains|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="14021" PostTypeId="1" CreationDate="2018-04-28T15:53:37.017" Score="4" ViewCount="54" Body="&lt;p&gt;Does anyone have a resource on what airports (or other recording stations) have been recording temperature continuously (daily) for quite a while?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I remember reading that some back to the 1910s/1920s, but I am having trouble finding resources on which airports, and of course getting my hands on the records themselves. I would like very much to find such resources.&lt;/p&gt;&#xA;" OwnerUserId="12801" LastActivityDate="2018-05-01T16:39:49.893" Title="Airports with longest continuous temperature records" Tags="|temperature|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="14022" PostTypeId="1" CreationDate="2018-04-28T18:52:15.170" Score="1" ViewCount="5687" Body="&lt;p&gt;CERN is a scientific site developed to create anti matter. Does this have any negative impact on the environment? &lt;/p&gt;&#xA;" OwnerUserId="11565" LastEditorUserId="725" LastEditDate="2018-04-29T01:28:51.337" LastActivityDate="2020-03-02T10:35:46.487" Title="Effects of CERN on earth's magnetic field?" Tags="|earth-observation|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 3.0" />
  <row Id="14025" PostTypeId="2" ParentId="14022" CreationDate="2018-04-29T01:35:53.660" Score="14" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;CERN is a scientific site developed to create anti matter&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The scientific activity at CERN involves many things, anti matter being just one of them. For more information you can read their &lt;a href=&quot;https://home.cern/topics/antimatter&quot; rel=&quot;noreferrer&quot;&gt;anti matter page&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Does this have any negative impact on the environment? &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No. The amount of anti matter is negligible. Any anti matter produced in CERN is also annihilated at CERN as well and does not &quot;escape&quot; outside into the environment. The CERN experiments require lots of power, so there are power plants that have their own environmental impact. There are also people driving and flying to CERN, but those are indirect environmental effects that are not directly due to the experiments.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Effects of CERN on earth's magnetic field?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;CERN has large magnets that are used in their experiments. &lt;a href=&quot;https://home.cern/about/engineering/pulling-together-superconducting-electromagnets&quot; rel=&quot;noreferrer&quot;&gt;Their magnetic field is 100,000 times the Earth's magnetic field!&lt;/a&gt; But, the magnetic field is constrained to CERN itself and has no effect outside of CERN, and it definitely has no effect on Earth's magnetic field itself.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-04-29T01:35:53.660" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="14026" PostTypeId="2" ParentId="14022" CreationDate="2018-04-29T08:37:48.940" Score="10" Body="&lt;p&gt;In addition to @Michael's &lt;a href=&quot;https://earthscience.stackexchange.com/a/14025/12645&quot;&gt;excellent answer&lt;/a&gt;, keep in mind that fields from charges drop off with the inverse of the distance squared and from dipoles (like those of the Earth and a lot of CERN's larger experiments) with inverse distance cubed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take for example the magnet used in the LHCb experiment at CERN. It is a large dipole magnet with a maximum field strength a bit above 1T (the Earth's magnetic field is on average about 40-50 uT strong). This puts it in a similar category as the magnets used to bend the proton beams to keep them going in circles in the LHC (which have field strengths of about 7.7T).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As can be seen in the following picture, at a distance of 5m this has been reduced to 20 mT (the line with label 3), so by about a factor one thousand. This is still a thousand times stronger than the Earth's magnetic field, but continuous work for authorised persons is already permitted at 200mT.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rTPXi.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rTPXi.jpg&quot; alt=&quot;description&quot;&gt;&lt;/a&gt;Taken from the &lt;a href=&quot;http://lhcb-magnet.web.cern.ch/lhcb-magnet/TDR/html/lhcb-magnet.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;technical design report of the LHCb magnet&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition you should keep in mind that this experiment (and indeed the whole LHC) is about 100m underground, so the magnetic field from the magnets is basically undetectable at ground level, even right above it.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;There are, however, other potential effects on the environment:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The accelerator consumes a huge amount of power (&lt;a href=&quot;https://home.cern/about/engineering/powering-cern&quot; rel=&quot;nofollow noreferrer&quot;&gt;about 200 MW at it's peak&lt;/a&gt;). Generating this power has an impact on the environment, as already mentioned.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Materials can get activated when being irradiated by the beams. These materials (most notably anything made of iron) are kept under radiological supervision and can only be taken out of the underground area if there is no radioactivity detectable (anymore). One does not want to contaminate the environment with radioactive materials.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some detector components contain substances which are regulated because of their impact on the environment (because they are greenhouse gases). The LHCb RICH1,  for example, contains perfluorbutan (C4F10). The amounts are negligible on a global scale, though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://beryllium.eu/beryllium-beam-pipe-used-in-centrepiece-of-cern-large-hadron-collider/&quot; rel=&quot;nofollow noreferrer&quot;&gt;beam pipe at the interaction regions consists of Berryllium &lt;/a&gt;, whose dust is toxic. Special care is needed when working around it (and probably when dismantling it at some point).&lt;/p&gt;&#xA;" OwnerUserId="12645" LastEditorUserId="12645" LastEditDate="2020-03-02T10:35:46.487" LastActivityDate="2020-03-02T10:35:46.487" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14027" PostTypeId="1" AcceptedAnswerId="14039" CreationDate="2018-04-29T15:18:58.733" Score="7" ViewCount="184" Body="&lt;p&gt;My son asked me at the beach how are &quot;sand stones&quot; formed. These are the solid (but fragile) sand conglomerates which you can hold in your hand and which crumble to sand once pressed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RDUtV.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RDUtV.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZvEf3.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZvEf3.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TOLUs.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TOLUs.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried some hand waving about &quot;cement-like&quot; formations and how these grains of sands are held together because they dried &quot;in a specific way&quot; but he was not impressed and neither was I.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a name for these structures so that I can look up how they are formed?&lt;/p&gt;&#xA;" OwnerUserId="7288" LastEditorUserId="2570" LastEditDate="2018-05-01T20:24:01.917" LastActivityDate="2018-05-01T20:24:01.917" Title="How are sand blocks formed?" Tags="|sedimentology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="14029" PostTypeId="1" AcceptedAnswerId="14031" CreationDate="2018-04-29T17:12:46.877" Score="3" ViewCount="581" Body="&lt;p&gt;It is interesting to compare estimated Earth abundances with estimated Milky way abundances.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously the hydrogen and helium were gaseous and too light for Earth's gravitational field (other than hydrogen in molecules like H2O).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oxygen is the second most abundant element on Earth. Even though it can exist in the gaseous O2 form, I assume this is because of how it combines with so many heavier elements and is trapped in the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Carbon, neon and nitrogen however have a much lesser abundance in the Earth than cosmic abundances. Can we assume that this is proof that there was a solar event that blew most of the gases away during early planetary formation. (Carbon because of its gaseous form in CO and CO2)?&lt;/p&gt;&#xA;" OwnerUserId="4600" LastActivityDate="2023-05-29T22:57:42.543" Title="Where did the carbon, neon and nitrogen go?" Tags="|earth-history|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 3.0" />
  <row Id="14030" PostTypeId="1" CreationDate="2018-04-30T03:11:00.990" Score="3" ViewCount="32" Body="&lt;p&gt;There are many graphic representations of the Earth's core, but I would like to know how did scientists determine what the core is made of, how hot it is, rotation etc. without actually being there? &lt;/p&gt;&#xA;" OwnerUserId="12811" LastActivityDate="2018-04-30T03:11:00.990" Title="How do we know what Earth's core is made of?" Tags="|core|earth-system|" AnswerCount="0" CommentCount="0" ClosedDate="2018-05-01T00:15:14.860" ContentLicense="CC BY-SA 3.0" />
  <row Id="14031" PostTypeId="2" ParentId="14029" CreationDate="2018-04-30T11:41:03.050" Score="3" Body="&lt;p&gt;The reason Carbon and Nitrogen are rare on Earth compared to their abundance in space is because elements containing carbon and nitrogen didn't survive the heat of the sun at Earth's distance during the &lt;a href=&quot;https://en.wikipedia.org/wiki/Protoplanetary_disk&quot; rel=&quot;nofollow noreferrer&quot;&gt;protoplanetary disk stage&lt;/a&gt;.   Carbon can form carbonate rock, but only under certain circumstances.  Carbonate rock is rare in space and most of the carbon is in the form of Carbon dioxide.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oxygen, unlike Carbon or Nitrogen, bonds readily with Silicon, Magnesium, Iron and other heavy elemets, which is why Oxygen is very abundant in rocky planet formation.  It's one of the elements abundant in space-dust, unlike CO2, H20, CH4, NH3, which can form, in colder regions, ice or snow like formations as they begin to clump together, but only in cold regions of space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sun didn't precisely have an &quot;event&quot;, though young stars after formation can be much more violent.  The initial heat of formation can be very bright and very hot, and young stars are usually rotating very fast and prone to much bigger solar storms and very large mass ejections.   Pretty much all stars go through a violent youth.  It's not a unique event to our solar-system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Common elements in space, such as CO2, H20, CH4 and NH3 are gaseous at Earth's distance from the sun and as a result, are unlikely to stick to anything in the Earth's formation region.   This is true for all 4 inner planets and likely all rocky worlds.   Rocky planets likely can only form close to their star, just as gas giants, ice giants or other icy abundant bodies like comets and low-density moons, can only form further out.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gases like the 4 above can begin to be retained around a planet after it reaches a sufficiently large mass with low enough surface temperature to retain those gases by gravity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The boundaries where CO2, H20, CH4, NH3 and other gases can be found in the protoplanetary disk is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Frost_line_(astrophysics)&quot; rel=&quot;nofollow noreferrer&quot;&gt;the frost line&lt;/a&gt;.  Different gases have different frost lines depending on their freezing point.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's thought that much of Earth's water, CO2, CH4 and NH3 came to the Earth by comet after the planet formed.  There's still some uncertainty on the percentages, as some of those elements could have been trapped during formation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just to add, hydrogen and helium are obviously abundant, but will only begin to accrue around a planet of a certain mass.  In our solar-system, only Jupiter and Saturn are massive enough to accrue hydrogen and helium.   That's why Uranus and Neptune are relatively low on hydrogen and helium compared to the universal abundance.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Argon is in Earth's atmosphere because it forms from gradual radioactive decay of Potassium-40.   Earth's Helium is also present as a result of radioactive decay.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2018-04-30T11:41:03.050" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="14032" PostTypeId="1" CreationDate="2018-04-30T14:03:34.697" Score="4" ViewCount="440" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Scala_dei_Turchi&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scala dei Turchi&lt;/a&gt; i (Italian: &quot;Stair of the Turks&quot;) is a rocky cliff on the coast of Realmonte in Italy:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KyY8B.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KyY8B.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;sup&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Scala_dei_Turchi#/media/File:Scala_dei_Turchi_panorama.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Scala_dei_Turchi#/media/File:Scala_dei_Turchi_panorama.jpg&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How is the shape of a staircase formed?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could it be some sort of stretching process?&lt;/p&gt;&#xA;" OwnerUserId="12815" LastEditorUserId="2570" LastEditDate="2018-05-01T21:24:44.437" LastActivityDate="2018-05-01T21:24:44.437" Title="How are the Scala dei Turchi staircases formed?" Tags="|geology|sedimentology|geomorphology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 3.0" />
  <row Id="14034" PostTypeId="2" ParentId="14032" CreationDate="2018-05-01T07:32:26.470" Score="3" Body="&lt;p&gt;There's no need to invoke stretching here. This is just a simple case of dipping sedimentary beds which have been eroded by the sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The stepped geometry may be caused by small variations in the hardness of the beds such that the harder beds weather out more prominently and create the steps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alternatively, at least some of the larger steps may be wave cut terraces formed during periods of stable sea level. In the background on the left of the picture you can see two large terraces separated by a ramp which look very much like wave cut terraces. Such terraces are well known from central Greece, where they have been uplifted by activity on faults and I would speculate that a similar process has occurred here.&lt;/p&gt;&#xA;" OwnerUserId="2570" LastEditorUserId="2570" LastEditDate="2018-05-01T20:12:44.773" LastActivityDate="2018-05-01T20:12:44.773" CommentCount="3" ContentLicense="CC BY-SA 3.0" />
  <row Id="14035" PostTypeId="2" ParentId="4996" CreationDate="2018-05-01T15:54:24.720" Score="1" Body="&lt;p&gt;This paper basically summarizes the thinking behind the highly-productive mammoth step theory:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Zimov, S.A., Zimov, N.S., Tikhonov, A.N., Chapin, F.S., 2012. Mammoth steppe: a high-productivity phenomenon. Quaternary Science Reviews 57, 26–45. &lt;a href=&quot;https://doi.org/10.1016/j.quascirev.2012.10.005&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/j.quascirev.2012.10.005&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The idea is basically that a large herbivore density (comparable to modern day intact African Savannah ecosystems) kept soil moisture low and reduced permafrost temperatures. This was favoring gramminoids (grass like plants) that are much more productive than the present day prevailing mosses. Plant productivity in these regions is usually limited by nitrogen (other ecosystems are carbon limited). The higher than today herbivore population provided a lot of nitrogen input from dung and urine propelled the productivity of plants, which in turn allowed for more herbivores. Low temperatures and shorter summers also limited damage to gramminoids, thus they could grow faster in the next season. The ecosystem had several positive feedback mechanisms sustaining high productivity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When humans arrived in the region, they hunted all the herbivores. The system collapsed and lost its productivity. &lt;/p&gt;&#xA;" OwnerUserId="364" LastActivityDate="2018-05-01T15:54:24.720" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="14036" PostTypeId="2" ParentId="14021" CreationDate="2018-05-01T16:39:49.893" Score="1" Body="&lt;p&gt;I found a pretty easy-to-digest resource from NOAA here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;ftp://ftp.ncdc.noaa.gov/pub/data/noaa/isd-history.csv&quot; rel=&quot;nofollow noreferrer&quot;&gt;ftp://ftp.ncdc.noaa.gov/pub/data/noaa/isd-history.csv&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It has a list of temperature sources (including airports), with their start/end dates that they were measuring.&lt;/p&gt;&#xA;" OwnerUserId="12801" LastActivityDate="2018-05-01T16:39:49.893" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="14037" PostTypeId="2" ParentId="13851" CreationDate="2018-05-01T17:55:43.573" Score="4" Body="&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;It seems difficult to find a reasonable proxy species for $\mathrm{NH}_3$, since its sources (primarily agriculture) are quite distinct from the sources of more commonly observed pollutants. Some observations of aerosol-bound $\mathrm{NH}_4^+$ might (or might not) be available, but due to the reasons you explain, it is non-trivial to infer the gas-phase $\mathrm{NH}_3$ concentration from the $\mathrm{NH}_4^+$ in aerosols.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;There are papers about estimating atmospheric $\mathrm{NH}_3$ from satellite data, see for example &lt;a href=&quot;https://www.atmos-chem-phys.net/14/2905/2014/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; or &lt;a href=&quot;https://www.atmos-chem-phys.net/16/5467/2016/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. These are for column-integrated and not surface $\mathrm{NH}_3$, however.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="859" LastActivityDate="2018-05-01T17:55:43.573" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="14039" PostTypeId="2" ParentId="14027" CreationDate="2018-05-01T19:17:47.003" Score="3" Body="&lt;p&gt;There are two &quot;normal&quot; mechanisms for this effect:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clay bonding, the beach sand contains a small fraction of clay particles which bond to the grain surfaces and hold the sand together when dry, this is normally the mechanism where the beach is backed by mudstone cliffs or quite close to river mouths supplying fine sediment to the beach.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Evaporite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Evaporite&lt;/a&gt; &lt;a href=&quot;https://en.wikipedia.org/wiki/Cementation_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cementation&lt;/a&gt; this is the more widespread and common process then what you are seeing is a small scale, and often abortive/short-lived formation of &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Beachrock&quot; rel=&quot;nofollow noreferrer&quot;&gt;Beachrock&lt;/a&gt;&quot; this is the most likely explanation and the cause will probably be a rainwater/seawater interaction on the surface of the beach where it is still wet with seawater but no longer wave-washed as the tide recedes.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-05-01T19:17:47.003" CommentCount="0" ContentLicense="CC BY-SA 3.0" />
  <row Id="14040" PostTypeId="2" ParentId="13851" CreationDate="2018-05-01T20:33:37.270" Score="3" Body="&lt;p&gt;There are some NH3 retrievals available from the TES instrument on the Aura/NASA satellite.  There are also some NH3 retrievals from the IASI instrument on the MetOP/ESA satellite.  You can read about the retrievals in these papers:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.atmos-meas-tech.net/8/1575/2015/amt-8-1575-2015.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Towards validation of ammonia (NH3) measurements from the IASI satellite&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.atmos-chem-phys.net/11/10743/2011/acp-11-10743-2011.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;TES ammonia retrieval strategy and global observations of the spatial and seasonal variability of ammonia&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These datasets are a good qualitative way to see ammonia spatial and temporal distribution across the globe.  However, do not expect to get good estimates of ammonia concentrations, since there is too much uncertainty in the retrieval.  In fact, I don't think these are &quot;operational&quot; products, and you will likely have to contact the research teams to get the data.  See the image below, where you can see the effects of albedo in Australia and Greenland cause large errors in the retrieval.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, you will see high NH3 near large sources like wildfires, livestock waste stockpiling, and crops with recent fertilizer application.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rU1tI.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rU1tI.png&quot; alt=&quot;IASI NH3&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Mean IASI-NH 3 total column distribution for the period between January 2008 and January 2015. The total columns are a weighted average of the individual observations weighted with the relative error. Red circles indicate the positions of the FTIR stations.&lt;/em&gt;&lt;/strong&gt;  source: &lt;a href=&quot;https://www.researchgate.net/figure/Mean-IASI-NH-3-total-column-distribution-for-the-period-between-January-2008-and-January_fig1_307568363&quot; rel=&quot;nofollow noreferrer&quot;&gt;An evaluation of IASI-NH3 with ground-based Fourier transform infrared spectroscopy measurements&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2018-05-03T04:45:25.873" LastActivityDate="2018-05-03T04:45:25.873" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14041" PostTypeId="1" CreationDate="2018-05-02T00:56:08.520" Score="5" ViewCount="86" Body="&lt;p&gt;I just had a little eureka moment!&#xA;I was looking again at this mid atlantic ridge along the western edge of the Eurasian plate.&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Lists_of_volcanoes&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Lists_of_volcanoes&lt;/a&gt;&#xA;How it and the way it links to the South American Plate it reminded me of something, so I checked and yes, it seems to closely parallel the movement of the gulf stream!&#xA;&lt;a href=&quot;https://scijinks.gov/review/gulf-stream/gulf-stream3.gif&quot; rel=&quot;noreferrer&quot;&gt;https://scijinks.gov/review/gulf-stream/gulf-stream3.gif&lt;/a&gt;&#xA;I'm no expert at all, but I'm going to venture that there is a correlation between the underwater geological activity and topology and the oceanic movement of warm and cold currents.&#xA;Would I be correct?&lt;/p&gt;&#xA;" OwnerUserId="12830" LastActivityDate="2018-05-02T00:56:08.520" Title="Is there a correlation between the underwater geological activity and topology of the mid Atlantic ridge/ South American plate and the Gulf Stream?" Tags="|plate-tectonics|ocean-currents|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14043" PostTypeId="2" ParentId="13990" CreationDate="2018-05-02T14:33:21.233" Score="1" Body="&lt;p&gt;What I have learned from this is that things were very different before the Great Oxygenation Event; more than just the same elements rearranged.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If all of the free oxygen came from water (and the hydrogen escaped to outer space), that isn't very different. That's around 10^18 liters of water lost from the oceans. The surface of the earth is about 5x10^14 square meters, one liter covers 10^-3 square meters, so sea level would have been somewhere vaguely around 2 meters higher. There's a whole lot of water in the world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;People say the atmosphere used to have 20% CO2 and that's where the oxygen came from. I didn't believe it because there is probably not that much reduced carbon in the world today. But it's possible that as the carbon was reduced, it was deposited on the sea floor and then it got subducted deep underground. It may still be there, waiting to get out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe there were other oxidized compounds that got reduced. The obvious candidates are nitrates and sulfates. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Today, bacteria mostly reduce nitrates when there is not enough free oxygen. In a series of steps they reduce it all the way to N2, getting energy at each step.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other bacteria convert N2 to ammonia, using considerable energy. Often the ones that do this are photosynthetic. They have N2 and not enough nitrogen compounds to meet their needs, so they make what they need. O2 damages the enzyme.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Possibly there used to be a lot more oxidized nitrogen dissolved in the ocean, and the balance shifted, resulting in both increased N2 and increased O2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe there used to be a whole lot more sulfur in the ocean, in the form of sulfates etc. Most of the sulfur got reduced and deposited in the form of elemental sulfur or iron sulfide etc. Then it got subducted away, removing the evidence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What was the pH of the ancient ocean? Various organic compounds can buffer pH differently according to concentration. H2CO2 (formic acid) acts different from H2 + CO2. Did the ocean used to be more acid? I don't know, and there were a lot of different buffers. Maybe H2CO3 (carbonic acid) was always the most important, if there was much more CO2 dissolved in the oceans than any other organic acid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just as this could happen for sulfur or iron, it could happen with any other good electron acceptor that happened to be dissolved in the ocean. Precipitate it out, and then subduction removes most of the evidence. But only things that had oxygen and then lost it, would contribute to free O2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It was very different, and I can't even assume that the amounts of the various elements present were like today. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If it isn't clear what the pH of seawater was back then, I can't even be sure what the maximum amount of dissolved stuff would be. When I tried to guess at the maximum amount of dissolved iron, it turns out it varies with pH, with the amount of other dissolved chemicals, strongly with the amount of organic carbon compounds (because living things in today's ocean can't get enough iron and they scavenge it aggressively), etc. But that's today's ocean, where dissolved iron is quickly oxidized.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I expect there's room for a whole lot of uncertainty about all that. But experts can still know some things about it.&lt;/p&gt;&#xA;" OwnerUserId="12787" LastEditorUserId="12787" LastEditDate="2018-05-05T10:39:23.250" LastActivityDate="2018-05-05T10:39:23.250" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14045" PostTypeId="1" CreationDate="2018-05-03T07:13:51.773" Score="3" ViewCount="310" Body="&lt;p&gt;I know there was a Pangaea at one point in history that broke into the continents of today, but I could have sworn there was another instance in Earth's history that there was a super continent, maybe even more, so how many in total? &lt;/p&gt;&#xA;" OwnerUserId="12086" LastActivityDate="2018-05-07T11:13:47.053" Title="How many times in total has Earth formed a super continent?" Tags="|plate-tectonics|earth-history|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14046" PostTypeId="1" AcceptedAnswerId="14051" CreationDate="2018-05-03T14:00:56.730" Score="0" ViewCount="155" Body="&lt;p&gt;Multiple papers (for example, &lt;em&gt;Limitations on impedance inversion&#xA;of band-limited reflection data&lt;/em&gt; Gosh[2000]) and textbooks covering seismic inversion mention a necessary component of any seismic inversion: the DC (or zero frequency) component. For lack of a better question, what does a &quot;zero frequency&quot; component look like? Also, why is this considered a necessary component of any complete seismic inversion scheme? &lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2018-05-03T23:09:54.647" Title="DC component: Seismic inversion" Tags="|seismic|inversion|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14051" PostTypeId="2" ParentId="14046" CreationDate="2018-05-03T23:03:53.370" Score="1" Body="&lt;p&gt;The impedance inversion problem asks: &quot;Recover acoustic impedance from seismic reflection waveforms&quot;. The forward modeling procedure from acoustic impedance to seismic reflection waveforms involves calculating reflection coefficients and then convolving these with a wavelet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's assume, for now, that you have perfect seismic resolution and therefore your wavelet is of infinite bandwidth. This means that the inversion problem becomes: &quot;Recover the acoustic impedance from a given set of reflection coefficients&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As shown by Peterson et al. (1955), for small contrasts in acoustic impedance, the reflection coefficient equation can be linearized as shown below. Linear problems are much much easier to solve computationally than non-linear. This makes the forward model calculation a simple difference, the discrete analog to a derivative. Note: this is for normal incidence but a similar analysis can be done for non-normal incidence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UZao0.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UZao0.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So... if it takes a derivative to calculate the reflection coefficient, it must take an integral to calculate the acoustic impedance. However, as everyone knows, when you integrate any function, you inevitably run into the non-uniqueness caused by that dreaded +C at the end of all integrals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That +C, in this context, means that there are an infinite number of acoustic impedance models that can give you the exact same reflection coefficients. So you need the +C (i.e. the DC, or zero frequency, or additive constant) information to do a complete inversion and really recover the true values of impedance in the earth. All you get from the seismic are the reflection coefficients (and that's with infinite resolution), so you will need to get this DC information from another independent source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In practice, the inversion is not done by a simple integration but by setting up a linear system and iteratively converging (by something like conjugate gradient) to the answer that minimizes some misfit function between the forward model and the data. As complex as that sounds, deep down, we are pretty much just doing a careful integration.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope that helped.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Peterson, R. A., W. R. Fillippone, and F. B. Coker, 1955, The synthesis of&#xA;seismograms from well log data: Geophysics, 20 (3), 516–538.&lt;/p&gt;&#xA;" OwnerUserId="4636" LastEditorUserId="4636" LastEditDate="2018-05-03T23:09:54.647" LastActivityDate="2018-05-03T23:09:54.647" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14055" PostTypeId="1" CreationDate="2018-05-04T15:05:17.400" Score="1" ViewCount="379" Body="&lt;p&gt;Rock found on Laguna Beach. It is not sand stone and is heavy for its size 3&quot; x 2&quot;. It is rather dense.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Click the image for full size:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MiHgl.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MiHglm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12846" LastEditorUserId="6031" LastEditDate="2018-05-07T11:36:39.180" LastActivityDate="2018-05-07T11:36:39.180" Title="I found this rock on Laguna Beach" Tags="|rocks|" AnswerCount="0" CommentCount="6" ClosedDate="2018-05-11T06:59:38.923" ContentLicense="CC BY-SA 4.0" />
  <row Id="14056" PostTypeId="2" ParentId="4309" CreationDate="2018-05-04T16:41:57.793" Score="1" Body="&lt;p&gt;Answers:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A) ITCZ and Monsoon Trough are the zones around Earth’s equator where winds of both hemispheres meet. Winds blow from areas of high pressure (cold air masses) towards areas of low pressure (warm air masses). That means in a simple way, that winds blow from the poles towards the equator and their direction is affected by Earth’s rotation. Obviously the sun’s energy warms Earth more around the equator than at the poles.&#xA;The difference between the ITCZ and the Monsoon Trough is simply the &lt;strong&gt;direction&lt;/strong&gt; of the winds from both hemispheres when they meet. Usually, winds from northern hemisphere blow from NW to SE and those of the southern blow from SW to NE. During the northern hemisphere summer, the winds from the northern hemisphere sometimes change direction from NE to SW. When this occurs you have a Monsoon Trough. Due to the new movement of winds they favor the genesis of vorticity around very low pressures which in turn could form more easily tropical cyclones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;B) The shifting of ITCZ is the result of the Earth’s rotation, axis inclination and the translation of Earth around the Sun. Seasons are the result of this. ITCZ moves toward the hemisphere with most heat, wich are either hemisphere summers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;C) “Convergence” means that the winds from every hemisphere blow towards the same point, or more accurately, the same line in this case the equator. That’s precisely why it is called the Intertropical (between the tropics), Convergence (winds blow towards equator) Zone (it is a wide area along the equator obviously).&#xA;It should be pointed out that the term “Monsoon” alone refers simply to the rains produced by the shift nortwards or southwards of the ITCZ during summer of either hemisphere as in northern India, making the rains seasonal.&lt;/p&gt;&#xA;" OwnerUserId="12848" LastEditorUserId="12848" LastEditDate="2018-05-17T01:19:17.020" LastActivityDate="2018-05-17T01:19:17.020" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14057" PostTypeId="2" ParentId="346" CreationDate="2018-05-04T20:17:20.403" Score="-5" Body="&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/0031018295000712&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bennet et al&lt;/a&gt; showed that there are several origins of the 'dropstones' not associated to glacial deposits. The dropstones are the sole material, circunstantial, presented as evidence of global glaciations.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The whole story started because of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Faint_young_Sun_paradox&quot; rel=&quot;nofollow noreferrer&quot;&gt;Faint Young Sun&lt;/a&gt; - only 70% of energy output leads to a frozen Earth - a Paradox because there was liquid water on Earth and Mars that required a Hot Past. The same with Mars Hot past (the CO2 feedback as a source of heat preservation was dismissed recently).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We have already strong biological and geological evidences, that can not be dismissed, against the Snowball Earth old theory:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Molecular phylogeny&lt;/strong&gt; - Life’s evolution is strongly dependent in ambient thermal evolution &lt;strong&gt;as recorded by Life itself&lt;/strong&gt; and demonstrated in:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The &lt;strong&gt;resurrected proteins&lt;/strong&gt; - &lt;a href=&quot;https://www.nature.com/articles/nature06510&quot; rel=&quot;nofollow noreferrer&quot;&gt;Paleotemperature trend for Precambrian&lt;br&gt;&#xA;life inferred from resurrected proteins&lt;/a&gt;, Nature 451, 704-707 (doi:&#xA;10.1038/nature06510 Letter)”. Gaucher &amp;amp; al., 2008. &lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.pnas.org/content/early/2017/04/11/1702729114&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Reconstructed ancestral enzymes&lt;/strong&gt; suggest long-term cooling of Earth’s photic zone since the Archean&lt;/a&gt; – Amanda Garcia et al, 2017&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Geological records&lt;/strong&gt; have the same trend of high temperature in the past (∂18O(Knauth &amp;amp; Epstein, 1976) or of ∂30Si (Robert &amp;amp; Chaussidon, 2006) indicate a sea temperature above 65 ºC, eventually close to 90 ºC, earlier than 2 Ga. Several other studies confirm the results. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The Life, ie all cells - can only use monoatomic &lt;strong&gt;N&lt;/strong&gt;(itrogen) that is not freely available on Earth. The atmospheric molecular &lt;strong&gt;N2&lt;/strong&gt; require huge pression and temperatures to be dissociated in &lt;strong&gt;N+N&lt;/strong&gt; as used in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Haber_process&quot; rel=&quot;nofollow noreferrer&quot;&gt;Haber-Bosch&lt;/a&gt; process invented in the start of XX century (ammonia to fertilize the soil and feed the humanity - growing exponentially since the 30s). Until then Life had to feed on itself (a shitty recycle) and the total bioma could not grow. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;The habitat of the &lt;strong&gt;most ancient life forms&lt;/strong&gt; are in the thermal vents (very high temperature and pressure)&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;The mammals and birds&lt;/strong&gt; – the last major Life's creation – are equipped with protective furs and feathers and the internal &lt;strong&gt;metabolism&lt;/strong&gt; novelty to keep the ideal temp around 40ºC and the species unadapted to colder times got extinguished&lt;/li&gt;&#xA;&lt;li&gt;The &lt;strong&gt;proto-feathers&lt;/strong&gt; favoured the Heat dissipation (see image bellow)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The conclusion can only be: The Snowball Earth Theory is dead&lt;/strong&gt;.&lt;br&gt;&#xA;But ... to solve the conundrum we have to put the planets closer to the Sun in the past or increment it's energy output. A new theory?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A paradigm shift was motivated by the following &lt;strong&gt;considerations&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A &lt;strong&gt;rationalistic&lt;/strong&gt; mind, following Descartes, Spinoza and Poincaré...,&#xA;can never accept that the space is expanding at the expense of&#xA;nothing, without a cause.  &lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;We measure&lt;/strong&gt; everything with atomic properties (atoms), thus, we can not measure the evolution of the atom itself; f.i. the mass unit ‘kilogramme’ is the mass of an ensemble of atoms as represented in Paris prototype. Thus, one atom’s mass is a definite part of that unit – a definition in loop - and the same definition holds true, and the universe keeps going, if in the past the atoms were a billion times larger than the ones we have now.&lt;/li&gt;&#xA;&lt;li&gt;The &lt;strong&gt;redshift&lt;/strong&gt; of the radiation we receive from the past can be&#xA;interpreted as the emission from larger atoms&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Two studies were concluded outside the academia (not peer reviewed - blame the system and not the author):&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;A rational explanation of the observed space expansion is derived in &lt;a href=&quot;http://vixra.org/pdf/1107.0016v1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;A self-similar model of the Universe unveils the nature of dark&#xA;energy&lt;/a&gt; and it is formally proved that the &lt;strong&gt;atoms are shrinking&lt;/strong&gt; (the units Mass-Charge-Length-Time evolve at the same pace - to source the energy of the electrostatic and gravitational expanding fields). The obvious consequence is that the space seems to be expanding.&lt;/li&gt;&#xA;&lt;li&gt;From the available data the Evolving Climate Model (ECM) was derived - &lt;a href=&quot;http://vixra.org/pdf/1412.0170v1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;A model of past Earth’s climate from isotopic and biologic data and its relationship with orbits’ expansion&lt;/a&gt; and the initial environment favorable to the Emergence of Life is obtained. An abiotic origin  of Earth' Oxigen is presented and why Life was able to capture all the monoatomic N it uses.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Edit add:&lt;br&gt;&#xA;Some (a lot of) people have prejudice against new ideas that appear out of the academia. In this case the new ideas grew in front of my eyes decades ago and if you find any error or anything to be better explained in those docs you can ask me. Be polite and do not pretend to judge them without reading the content as it seems to be the usual case. The first doc has more than 1000 downloads and not a single error was mentioned until now. Be the first to argue.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quoting 'ressurected proteins' doc:  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Our results are further supported by a nearly identical cooling trend&#xA;  for the ancient ocean as inferred from the deposition of oxygen&#xA;  isotopes. The convergence of results from natural and physical&#xA;  sciences suggest that ancient life has continually adapted to changes&#xA;  in environmental temperatures throughout its evolutionary history.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Fig 3 from the 'ressurected proteins' doc with the past temperature on Earth as recorded by Life that is incompatible with SBE&#xA;&lt;a href=&quot;https://i.stack.imgur.com/dTIKo.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dTIKo.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(proto-feathers - Ramphorhyncus longicaudus at Teylers Museum – Haarlem)&#xA;  &lt;a href=&quot;https://i.stack.imgur.com/3vVdi.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3vVdi.jpg&quot; alt=&quot;proto-feathers - Ramphorhyncus longicaudus at Teylers Museum – Haarlem&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit Add&lt;/strong&gt;:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Due to the fact that basic logic is absent in the comments ( ‘Atoms are not shrinking. I assume the rest of this answer is equally silly’)  I’ll have to extend the implications of the Considerands above expressed to show that the downvotes are due to the lack of appropriated knowledge of laws of Logic and/or Physics. Playing with Legos or scaled trains/cars, designing Computer Models of the reality or &lt;a href=&quot;https://en.wikipedia.org/wiki/Similitude_(model)&quot; rel=&quot;nofollow noreferrer&quot;&gt;engineering scaled material models (similitude)&lt;/a&gt; can give a better insight of the solution here briefly described.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;strong&gt;2nd consideration&lt;/strong&gt; “We measure...” was intended to show explicitly that the units of measure are in one to one correspondence with the atom properties with the example of atomic mass. It is obvious, by definition, that the same is true irt the charge unit. The length unit can be assumed to be in a one to one correspondence to the atomic Bohr radius. Assuming the constancy of the light speed ‘c’ the Time T is tied to the Length unit. The simple and intuitive mode of reasoning is this one ‘without atoms we have no units of measure at all then it follows that the units are in correspondence with the atom, whatever its actual ‘size’’.&#xA;From this I see a logical error in the statement  “Atoms are not shrinking” because no law of physics have stated that and I’m sure that it is not missing such law.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To hold the validity of physical laws requires to hold the invariance of non-dimensional combination of quantities and constants (e.g., &lt;a href=&quot;https://en.wikipedia.org/wiki/Buckingham_%CF%80_theorem&quot; rel=&quot;nofollow noreferrer&quot;&gt;$\pi$ theorem&lt;/a&gt;); this implies that the relationship between correspondent base units has to be the same. Thus, the units Mass M, Charge Q, Length L, Time T had to evolve at the same pace, lets say&lt;br&gt;&#xA;$$\frac{[M_0]}{[M_1]}=\frac{[M_0]}{[M_1]}=\frac{[Q_0]}{[Q_1]}=\frac{[T_0]}{[T_1]}= \alpha(t)$$ and $\alpha$ function is the atomic scaling function.&lt;br&gt;&#xA;The velocity is invariant $\frac{L\alpha}{T\alpha}$&lt;br&gt;&#xA;The energy scale function is $\alpha$; being&lt;br&gt;&#xA;$E_0 =  M\ L^2\ T^{-2} \\&#xA;E_1= M\alpha\ L^2 \alpha^2\ T^{-2}\ \alpha^{-2}=E_0\alpha $&lt;br&gt;&#xA;The acceleration and gravitational field $L\ T^{-2}$ scale as $\alpha^{-1}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lets see some examples:&lt;br&gt;&#xA;The electron mass $m_e$ is left as a free parameter in Quantum Mechanics and in Atomic Physics but the ratios of the masses of particles have to be the same.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;strong&gt;3th consideration&lt;/strong&gt;: “The redshift of the radiation we receive from the past can be interpreted as the emission from larger atoms” was scrutinized at PSE and showed the impossibility to distinguish the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydrogen_spectral_series&quot; rel=&quot;nofollow noreferrer&quot;&gt;spectrum of the atomic radiation&lt;/a&gt; emited from an atom in motion and the one of a scaled atom - &lt;a href=&quot;https://physics.stackexchange.com/questions/119169/how-to-distinguish-between-the-spectrum-of-an-atom-in-motion-and-the-one-of-a-sc&quot;&gt;PSE&lt;/a&gt;  as acknowledged by the author of the  &lt;a href=&quot;https://physics.stackexchange.com/a/142562/1257&quot;&gt;accepted answer&lt;/a&gt;, after clarification that Wolfram equation on the hyperfine structure he used was indeed wrong.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lets see that the Force is invariant under that transformation:&lt;br&gt;&#xA;Newton 2nd law $F=mass\ \cdot\ acceleration$ (in SI units $kg*m/s^2$) and in dimensional analysis &#xA;$F_1=\frac{M\cdot\ L}{T^2}=\frac{M\cdot\ \alpha\cdot\ L\cdot\ \alpha}{(T\cdot\ \alpha)^2}=F_0\cdot 1$&lt;br&gt;&#xA;The force of gravitation (Newton) has the same value $F_g=G\cdot\frac{M^2}{L^2}=G\cdot\frac{(M\ \alpha)^2}{(L\ \alpha)^2}$ and the same is valid to the electomagnetic Coulomb force.&lt;br&gt;&#xA;The parameters $G,\varepsilon_0,c$ are invariant and the same irt the dimensionless constants.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_dimensionless_quantities&quot; rel=&quot;nofollow noreferrer&quot;&gt;list of the dimensionless quantities&lt;/a&gt; &#xA;we can pick any of these and check what happens, f.i.:&lt;br&gt;&#xA;The  &lt;a href=&quot;https://en.wikipedia.org/wiki/E%C3%B6tv%C3%B6s_number&quot; rel=&quot;nofollow noreferrer&quot;&gt;Eötvös or Bond number&lt;/a&gt; ( related to the shape of bubbles or drops) &#xA;$E_0=B_0=\frac{\delta\rho\ g\ L^2}{\sigma}$&#xA;where $\rho, g, L, \sigma $ are density, gravitational acceleration,   characteristic length and surface tension and in SI units $E_0\ units=[E_0] = \frac{kg/m^3\cdot m/s^2\cdot m^2}{kg*m/s^2/m}$ and inserting the scaling value we get for the system 1 the same value [E_0]&lt;br&gt;&#xA;$[E_1]=[E_0]\cdot scaling(\alpha)=\frac{kg/m^3\cdot m/s^2\cdot m^2}{kg\cdot\ m/s^2/m}\ \cdot \frac{\alpha/\alpha^3\cdot \alpha/\alpha^2\cdot \alpha^2}{\alpha\cdot\alpha/\alpha^2/\alpha} \\&#xA;=[E_0]\cdot \frac{\alpha^{1}\ \alpha^{-3} \cdot \alpha^{1}\ \alpha^{-2} \cdot \alpha^2}{\alpha^{1}\cdot\alpha^{1}\ \cdot \alpha^{-2} \alpha^{1}} \\&#xA;=[E_0]\cdot \alpha^{1-3+1-2+2-1-1+2-1} \\&#xA;=[E_0]\cdot \alpha^{0}=[E_0]$  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;strong&gt;1st consideration&lt;/strong&gt;  is a basic tenet of physics that never should have been forgotten and was indeed in the minds of all the physicists a century ago.  The difficulty of finding the correct explanation of the measured space expansion, besides the naif one: ‘the galaxies are moving away’ brougth philosophical problems and magical entities like the ‘dark’ energy, BB, inflation period, etc… in what in the universe is forbiden: ‘free lunches’.&lt;br&gt;&#xA;This new model is not a theory but a model because it was drawn from data with no ‘IFs’ and no hidden or undeclared, unverified, postulates like the one ‘the atoms are not shrinking’. Because in the laboratory there is no feasible experiment to make evident that the atoms evolve, or not, one can not jump to a conclusion without the theoretical analysis like the one done in this model.&lt;br&gt;&#xA;The actual function that describes the scaling of the matter was deduced to be $$\alpha(t_S)=e^{-H_0\cdot t_S}$$ and $t_S$ is the time unit of the system $S$ used as reference, a non evolving one.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the meantime I’m traveling the desert receiving up and downvotes from individuals that did not studied this issue and have no other way to answer the million dollar question, except ‘I assume/believe’:&lt;br&gt;&#xA;&lt;strong&gt;Is it the case that the space expands or the atoms that are shrinking?&lt;/strong&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now we have enough data and knowledge to say that the Snowball Earth theory is dead because it was proved wrong by the Life itself and by the geological records.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A final remark - I commented that the temperatures on the graph are lower than the real ones because a rise in the temperature makes the seawater to migrate to the atmosphere and the pressure and the boiling point rises too.  The studys only considered a standard  atmsphere of 1 bar.  &lt;/p&gt;&#xA;" OwnerUserId="2613" LastEditorUserId="2613" LastEditDate="2018-05-08T08:30:08.737" LastActivityDate="2018-05-08T08:30:08.737" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="14060" PostTypeId="1" AcceptedAnswerId="14064" CreationDate="2018-05-05T07:49:23.700" Score="3" ViewCount="74" Body="&lt;p&gt;Daily and monthly MODIS snow cover L3 data has downloaded, next to deal with missing and negative cells. &#xA;Different types of interpolation are being used to fill the missing cells. I want to fill the missing cells with mean of 3 surrounding values but it is very hard because in some cases large portion of data is missing?&#xA;I know to mask the NaN cell by using (nanmean) command and long term mean of same area can also be use.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Permafrost Presence/Absence Mapping of the Qinghai-Tibet Plateau Based on Multi-Source Remote Sensing Data but I am looking any possible way beside these.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the best way beside above mentioned two to deal the missing and negative cells of MODIS snow cover data? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note; I am using matlab environment for this purpose.&lt;/p&gt;&#xA;" OwnerUserId="12714" LastEditorUserId="12714" LastEditDate="2018-05-07T00:01:21.543" LastActivityDate="2018-05-07T00:01:21.543" Title="What is the better way to deal the missing and negative cells of satellite snow cover data" Tags="|climate|snow|data-analysis|modis|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14063" PostTypeId="2" ParentId="12977" CreationDate="2018-05-05T21:11:14.053" Score="1" Body="&lt;p&gt;There are two ways to answer your question: the first would be by verifying historical forecast data (calculating the difference to observed temperatures) and looking into a temperature dependency of these errors. This would certainly be doable - but in this context on Stackexchange not.&lt;/p&gt;&#xA;&lt;p&gt;So I suppose you refer to a general, more physically interpretable explanation what the difference in forecasting higher or lower temperatures is.&lt;/p&gt;&#xA;&lt;p&gt;Even though it makes a difference for physical processes like radiation and evaporation if temperatures are high or low, the characteristics stay the same - more explicitly said:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Temperature differences matter more than absolute temperatures!&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;For example:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The net radiation (budget) is proportional to the difference of soil and atmospheric temperature (each to the fourth power).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Deeper layers of soil keep the surface warm by transporting heat (also proportional to the temperature difference).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;and so on...&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;But there is a significant difference in the active physical processes:&#xA;At daytime (Tmax), the near surface air is (mostly) coupled to the temperature of higher layers of air by turbulence. On a sunny summerday, the surface air can not get significantly warmer than the air above because if it gets warmer, the air rises and cooler air from above cools the surface layer. In this way, the surface air temperature is 'tied down' so that it can not reach extrordinary temperatures without also heating up a say 1500 m boundary layer of air.&lt;/p&gt;&#xA;&lt;p&gt;If the surface air is cooler than the air above it gets decoupled from the temperatures above - turbulence is reduced, and theoretically the temperatures could drop a looong way down, until the incoming (longwave) radiation from the atmosphere (say hi to greenhouse gases) stops this temperature drop. The equilibrium temperature depends mostly on the amount of water vapor above our heads -&amp;gt; warmer in the tropics, cooler nights in polar regions. But the equilibrium is practically never reached. In most cases it is a dynamic thing with  ground heat flux and sporadic wind gusts - which are of very local effect.&lt;/p&gt;&#xA;&lt;h1&gt;Conclusion&lt;/h1&gt;&#xA;&lt;p&gt;Comparing these two cases one can see that the Tmax is more homogenously distributed in space because it mostly depends on the airmass. Minimum temperatures can be very different even for close locations because it really depends on your surrounding: trees, buildings, ridges. You can see the lowest Tmin at high altitude locations which are not exposed to wind gusts (sinkholes) which are covered by snow (isolated from soil heat).&lt;/p&gt;&#xA;&lt;p&gt;So by analyzing a forecast error dataset, you would most likely see that Tmax are more accurately forecast.&lt;/p&gt;&#xA;" OwnerUserId="3419" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-05-05T21:11:14.053" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14064" PostTypeId="2" ParentId="14060" CreationDate="2018-05-05T21:22:46.950" Score="3" Body="&lt;p&gt;You could fill the gaps with the analysis products of numerical weather prediction. NCAR for example (&lt;a href=&quot;https://rda.ucar.edu&quot; rel=&quot;nofollow noreferrer&quot;&gt;RDA UCAR&lt;/a&gt;) hosts the NCEP North American Regional Reanalysis (NARR) with data from 1979 to 2018 including snow cover (&lt;a href=&quot;https://rda.ucar.edu/datasets/ds608.0/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NARR&lt;/a&gt;) in 3-hourly intervals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I would guess it depends on your goal: &#xA;You can make an educated guess (bayesian approach, combining measured and predicted variables) about the true state of the snow cover, but what was not measured can not be pulled out of nowhere.&lt;/p&gt;&#xA;" OwnerUserId="3419" LastActivityDate="2018-05-05T21:22:46.950" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14067" PostTypeId="2" ParentId="14045" CreationDate="2018-05-06T09:10:26.087" Score="2" Body="&lt;p&gt;According to a review by &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S1674987112001570?via%3Dihub&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nance &amp;amp; Murphy (2013)&lt;/a&gt;, there are five known supercontinents, from the most recent to the most ancient: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Pangea (of course)&lt;/li&gt;&#xA;&lt;li&gt;Pannotia (though &lt;a href=&quot;https://www.researchgate.net/profile/R_Nance/publication/323514106_Supercontinents_and_the_case_for_Pannotia/links/5a9d98e84585155dc184bf6d/Supercontinents-and-the-case-for-Pannotia.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;it depends on how you define supercontinent&lt;/a&gt;), ca. 600 Ma&lt;/li&gt;&#xA;&lt;li&gt;Rodinia, breakup at ca. 750 Ma (see e. g. &lt;a href=&quot;http://dx.doi.org/10.1126/science.1083469&quot; rel=&quot;nofollow noreferrer&quot;&gt;Torsvik, 2003&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;Columbia (also called Nuna), ca. 1.6 Ga&lt;/li&gt;&#xA;&lt;li&gt;Kenorland, ca. 2.7 Ga&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Some additional ones such as Vaalbara in the Archean are still mostly speculative.&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2018-05-07T11:13:47.053" LastActivityDate="2018-05-07T11:13:47.053" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14068" PostTypeId="1" AcceptedAnswerId="14075" CreationDate="2018-05-07T05:03:34.170" Score="2" ViewCount="1198" Body="&lt;p&gt;News of Hawaii has got me thinking...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've lived in Taiwan for many years and hiked many kinds geologically interesting mountain and seashore rock formations, seen steaming, sulfury fumaroles, even ate my lunch in a (presumably long extinct) volcano crater. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From what I've learned from others, volcanism has a significant contribution to Taiwan's geology and geography.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But is this very old and no longer a factor?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Is there any historical reference to volcanic activity in Taiwan? Is there much chance of it again in the near future?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Screenshots from Google maps:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;left:&lt;/strong&gt; &lt;a href=&quot;https://zh.wikipedia.org/wiki/File:Da_You_Keng_Fumarole.JPG&quot; rel=&quot;nofollow noreferrer&quot;&gt;Da You Keng Fumarole&lt;/a&gt; (Chinese), &lt;strong&gt;right&lt;/strong&gt; (向天池山) Xiang Tian Chi Mountain (can't find a link), great for a caldera picnic. Images are screenshots from google maps. &lt;em&gt;Click for larger size&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8MFk5.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8MFk5m.jpg&quot; alt=&quot;Da You Keng Fumarole, Taiwan&quot;&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/U1OE0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/U1OE0m.jpg&quot; alt=&quot;Xiang Tian Chi Mountain, Taiwan&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2018-05-08T12:41:52.277" LastActivityDate="2018-05-08T12:41:52.277" Title="Volcanic activity in Taiwan, ever in recorded history, much chance in the near future?" Tags="|volcanology|volcanic-hazard|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14070" PostTypeId="1" CreationDate="2018-05-07T13:09:19.883" Score="5" ViewCount="264" Body="&lt;p&gt;I hear news of &quot;eruptive lava fissures&quot; opening up in Hawaii, nine of them at last count. But I don't understand what these are really.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are these existing, older lava tubes that are suddenly opening to the surface due to recent filling with new lava, or cracks that go through the crust to to deeper chambers of magma, or something else?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;update:&lt;/strong&gt; I've just seen a the video in the CBS News website's &lt;a href=&quot;https://www.cbsnews.com/news/kilauea-volcano-eruption-seismic-activity-today-earthquakes-2018-06-15/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kilauea volcano eruption: Seismic activity increases, earthquakes strike 5 days in a row&lt;/a&gt; (scroll down for this particular video). I wonder if there is a better or more technical visualization of the sources for the fissures somewhere?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vQSSa.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vQSSa.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="2470" LastEditDate="2023-09-03T07:17:36.327" LastActivityDate="2023-09-03T07:17:36.327" Title="Eruptive fissures in Hawaii associated with Kilauea; what are they? What is really happening?" Tags="|volcanology|volcanic-eruption|volcanic-hazard|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14072" PostTypeId="2" ParentId="14070" CreationDate="2018-05-07T19:53:35.317" Score="2" Body="&lt;p&gt;It can be either an eruption from the top of an existing tube or deep surface cracks opening up existing magmatic systems. I believe, from what I've been hearing in the news, that in this case they are in fact fresh fractures, tectonic in origin, that have relieved local over burden and allowed magma to rise to the surface in areas that had previously been dormant for an extended period.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-05-07T19:53:35.317" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14073" PostTypeId="2" ParentId="4425" CreationDate="2018-05-08T06:18:15.240" Score="2" Body="&lt;p&gt;My answer goes a little beyond the evidence -- there isn't much evidence.&#xA;&lt;br/&gt;&#xA;&lt;br/&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;The question&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;There's a lot of free oxygen now. This oxygen did not suddenly come from underground or from space. So it used to be attached to something. The question is, what was it attached to, and what happened to what it was attached to?&#xA;&lt;br/&gt;&#xA;&lt;br/&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Background&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;First off, there's every reason to think that bacteria already did oxidative phosporylation before there was any free oxygen. It does not require free oxygen, it requires an electron acceptor. O&lt;sub&gt;2&lt;/sub&gt; provides the most energy, but many other reactants provide &lt;em&gt;some&lt;/em&gt; energy, and the bacterial kingdom uses a bewildering variety of them. To use a different electron acceptor requires only one different enzyme -- the rest of the pathway can be the same.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So before there was free oxygen, prokaryotes did arbitrage -- they evolved to use the best electron donor/electron acceptor pair they could find under whatever conditions they faced at the moment. And everything they used for that had to be created in a cycle. Anything which they used up that was not replaced, would quickly be gone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Before there was free oxygen, photosynthesis still got done. Some bacteria used H&lt;sub&gt;2&lt;/sub&gt;S as an electron donor, creating S which could later be reduced for energy. Some created H&lt;sub&gt;2&lt;/sub&gt;. Some could reduce CO&lt;sub&gt;2&lt;/sub&gt; so that they could use the carbon and oxygen to make structures they needed. Some could not, but could still get energy from light. One way to do that was almost the same as oxidative phosphorylation, it used the absorbed light energy for electron transport instead of using redox energy, in practically the same pathway.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cycles. Every reaction must be undone, or its products will increase to the point that the reaction gets very slow. The exception is products that change state. A solid or gas product won't inhibit the reaction much.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, a bewildering variety of electron donors and acceptors. Photosynthesis creates energetic pairs of molecules or ions. Then redox creates less-energetic pairs of molecules or ions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What was it that was bound to oxygen in the old days, that was not bound later?&#xA;&lt;br/&gt;&#xA;&lt;br/&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Some possibilities&lt;/h2&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Hydrogen. One form of photosynthesis creates H&lt;sub&gt;2&lt;/sub&gt;. Maybe, at some times a whole lot of H&lt;sub&gt;2&lt;/sub&gt; was created which was lost to space. Just as much O and less H leaves room for O&lt;sub&gt;2&lt;/sub&gt; left over.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Sulfur. Maybe most of the sulfur in the oceans was stored as SO&lt;sub&gt;3&lt;/sub&gt;. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;H&lt;sub&gt;2&lt;/sub&gt; SO&lt;sub&gt;3&lt;/sub&gt; -&gt; S + H&lt;sub&gt;2&lt;/sub&gt;O +  O&lt;sub&gt;2&lt;/sub&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sulfur can be oxidized -- SO&lt;sub&gt;3&lt;/sub&gt;. Or it can replace Oxygen as an oxidizer -- H&lt;sub&gt;2&lt;/sub&gt;O -&gt; H&lt;sub&gt;2&lt;/sub&gt;S etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So by changing states it could affect free O&lt;sub&gt;2&lt;/sub&gt;. And solid sulfur could wind up on the ocean bottom where it would be subducted.&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;Heavy metals + sulfur. Maybe there was a lot of iron and nickel etc dissolved in the ancient ocean, along with a lot of sulfur. Iron sulfate is fairly soluble at room temperature, nearly 300 grams/liter. Provided it is not alkaline. But iron sulfide is not soluble. Lots of other heavy metals behave similarly. &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;F&lt;sub&gt;3&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt; +  4 H&lt;sub&gt;2&lt;/sub&gt;SO&lt;sub&gt;3&lt;/sub&gt; -&gt; F&lt;sub&gt;3&lt;/sub&gt;S&lt;sub&gt;4&lt;/sub&gt; + 6 O&lt;sub&gt;2&lt;/sub&gt; + 4 H&lt;sub&gt;2&lt;/sub&gt;0  (and many other combinations)&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;4&quot;&gt;&#xA;&lt;li&gt;Nitrogen. Nitrogen can be reduced to NH&lt;sub&gt;4&lt;/sub&gt; or oxidized to NO&lt;sub&gt;2&lt;/sub&gt; or NO&lt;sub&gt;3&lt;/sub&gt;. &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;2 NO&lt;sub&gt;2&lt;/sub&gt; + 4 H+ = N&lt;sub&gt;2&lt;/sub&gt; + O&lt;sub&gt;2&lt;/sub&gt; + 2 H&lt;sub&gt;2&lt;/sub&gt;O&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Perhaps there was a time when the atmosphere had only 75% as much N&lt;sub&gt;2&lt;/sub&gt; as it does now, and no O&lt;sub&gt;2&lt;/sub&gt;. This reaction would imply the oceans used to be more acidic than they are now. But there could be other reactions that would counteract that, and there were lots of other buffers.&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;5&quot;&gt;&#xA;&lt;li&gt;Silicon. Silicon is usually oxidized, SiO&lt;sub&gt;2&lt;/sub&gt;. It doesn’t have to have that ratio. Other silicon compounds are possible, eg carborundum SiC, and perryite Fe&lt;sub&gt;5&lt;/sub&gt;Si&lt;sub&gt;2&lt;/sub&gt; which is stable in acid water, silicon nitride Si&lt;sub&gt;3&lt;/sub&gt;N&lt;sub&gt;4&lt;/sub&gt;, silicon phosphide SiP&lt;sub&gt;2&lt;/sub&gt; etc . Siloxanes can have ratio Si:O of 1:1. Low molecular weight siloxanes are produced by modern anaerobic biogas fermenters, though it could possibly be eukaryotes producing them. There is potentially a tremendous amount of SiO&lt;sub&gt;2&lt;/sub&gt; available to release oxygen, although only a little of it is soluble at any one time. &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Or bacteria could have metabolized silicic acid into insoluble compounds that had less oxygen. This is entirely hypothetical since only a little carborundum has been discovered, and the rest would have had to be subducted. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Banded iron formations do though have layers of amorphous quartz. Silicon dioxide was being removed from the water. Perhaps it was alternately iron being removed while soluble siloxanes accumulated in water, and then the siloxanes were converted to silica and removed while iron accumulated in water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It was a complicated web of reactions. Photosynthesis provided the energy to create energy-rich chemicals. Meanwhile every organism that was not photosynthetic was busy finding its best mix of catalyzing chemical reactions that provided energy, versus creating the molecules needed to grow and reproduce. Strange things happened.&lt;/p&gt;&#xA;" OwnerUserId="12787" LastEditorUserId="12787" LastEditDate="2018-05-13T12:29:10.053" LastActivityDate="2018-05-13T12:29:10.053" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14074" PostTypeId="1" CreationDate="2018-05-08T09:29:06.520" Score="1" ViewCount="106" Body="&lt;p&gt;If hot air rises due to convection, how does it get colder when we climb mountains?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;After some research, I found out that atmospheric pressure affects the temperature of the surroundings. How does atmospheric pressure affect the surrounding temperature?&lt;/p&gt;&#xA;" OwnerUserId="12865" LastEditorUserId="28050" LastEditDate="2018-05-12T19:12:34.557" LastActivityDate="2018-05-12T19:12:34.557" Title="Atmospheric pressure and heat convection" Tags="|convection|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14075" PostTypeId="2" ParentId="14068" CreationDate="2018-05-08T11:21:53.483" Score="3" Body="&lt;p&gt;There are at least 9 old centres of volcanic activity in Taiwan: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Tatun_Volcano_Group&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tatun Volcano Group&lt;/a&gt; 15km north of Taipei, they think there are active magmatic systems there but the last eruption was 200,000 years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Chilung_Volcano_Group&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chilung Volcano Group&lt;/a&gt; in the north is extinct, with no magmatic activity and hasn't erupted in 800,000 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Guanyin_(New_Taipei)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mount Guanyin&lt;/a&gt; is listed as extinct but not a lot of work seems to have been published on it as a volcano.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Caoling Mountain is similarly extinct and no-one seems to have done any real work about it's eruptive history at all.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Guishan_Island_(Yilan)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Guishan Island&lt;/a&gt; is still active and last erupted in 1795, it could start a new eruption at any stage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Hai%27an_Range&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hai'an Range&lt;/a&gt; on the Eastern Coast is tectonically active and has experienced volcanism in the past which could recur at any time depending on the movement along that plate boundary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Green_Island,_Taiwan&quot; rel=&quot;nofollow noreferrer&quot;&gt;Green Island&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Orchid_Island&quot; rel=&quot;nofollow noreferrer&quot;&gt;Orchid Island&lt;/a&gt; off the East Coast are &lt;em&gt;old&lt;/em&gt; volcanoes of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Luzon_Volcanic_Arc&quot; rel=&quot;nofollow noreferrer&quot;&gt;Luzon volcanic Arc&lt;/a&gt; and haven't erupted in hundreds of millions of years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lastly there are the &lt;a href=&quot;https://en.wikipedia.org/wiki/Penghu&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pescadores&lt;/a&gt; out west, 90 odd volcanic atolls and small islands probably all monogenetic in origin (the individual volcanoes erupted only once in a given location but the area has experienced repeated eruptive cycles over geological time) none of the existing members is likely to erupt ever again but new volcanism in the region is likely at some stage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the long and short is that while it's been pretty quiet in Taiwan in the last couple of centuries there are areas where new eruptive cycles could start at any time at existing sites or new ones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please note any dates given are pretty approximate.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-05-08T11:21:53.483" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14076" PostTypeId="2" ParentId="845" CreationDate="2018-05-08T11:30:53.673" Score="2" Body="&lt;p&gt;It's reporting bias, and over longer time spans there's a preservation bias as well since a small eruption like &lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Ruapehu#Volcanic_activity&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ruapehu 1995-96&lt;/a&gt; will not show up in the fossil record &lt;em&gt;at all&lt;/em&gt; after a few hundred years of erosion. These days we watch the world from far more angles with far greater scrutiny than at any stage in the past so we see eruptions that we would never have paid attention to in the past that's all. That's why there are pronounced dips in the graph during the World Wars, volcanoes didn't stop but people were elsewhere with other things on their minds.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="10735" LastEditDate="2018-05-08T15:56:57.443" LastActivityDate="2018-05-08T15:56:57.443" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14077" PostTypeId="1" AcceptedAnswerId="14078" CreationDate="2018-05-08T13:34:01.453" Score="5" ViewCount="533" Body="&lt;p&gt;I was out in Swinley Forest in Bracknell(United Kingdom) last weekend. The area is a large pine forest but the ground is full of flint and is very sandy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I stumbled across a piece of flint and noticed that there were some very interesting marks on it. &lt;a href=&quot;https://i.stack.imgur.com/0gHt5.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0gHt5.jpg&quot; alt=&quot;Flint rock with potential fossil.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see on the right edge of the rock there is an indentation with some vertical lines and some circular patterning. I've included a zoomed in image below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is whether this could be plant fossil or even part of the fin of a fish with scales attached.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many thanks!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bep21.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bep21.jpg&quot; alt=&quot;Zoomed in image of Flint rock with potential fossil&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12867" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T07:44:23.280" LastActivityDate="2019-08-28T07:44:23.280" Title="ID on a potential flint fossil" Tags="|fossils|paleontology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14078" PostTypeId="2" ParentId="14077" CreationDate="2018-05-08T14:30:08.553" Score="4" Body="&lt;p&gt;Assuming that the identification of the rock as Flint/Chert and not Limestone/Dolomite is correct I'd say it's a formation artifact rather than a fossil. What I mean is that at some point as it was forming, flint can form in two ways one is due to silica saturated water acting on limestone and the other is by direct precipitation from mineral saturated water in shallow environments, the small bead-like structures were created within or on the surface of the rock. It may be a surface impression from a fossil that was once part of a larger piece but as it is now there's no evidence of a material difference between &quot;fossil&quot; and the country rock of the flint. This opinion is coloured by the fact that here in New Zealand fossils in our flint are vanishingly rare, I'm not sure if that holds in England though.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-05-08T14:30:08.553" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14083" PostTypeId="1" AcceptedAnswerId="14086" CreationDate="2018-05-08T22:17:17.047" Score="-1" ViewCount="111" Body="&lt;p&gt;What is (roughly) the half-life of the materials used/generated in a nuclear plant, if that plant goes into meltdown? Could the world bounce back from global warming in a shorter time period than that half-life? Even in a worst-case scenario, could full-scale global warming be a better outcome than a cascading series of nuclear power plant failures (due initially to a natural event such as an earthquake, or to deliberate attack, war, etc.)?&lt;/p&gt;&#xA;" OwnerUserId="12740" LastActivityDate="2018-05-10T15:42:25.843" Title="Global warming versus nuclear half-lives" Tags="|climate-change|" AnswerCount="1" CommentCount="6" ClosedDate="2018-05-09T20:43:57.347" ContentLicense="CC BY-SA 4.0" />
  <row Id="14084" PostTypeId="1" CreationDate="2018-05-09T07:30:20.127" Score="1" ViewCount="56" Body="&lt;p&gt;I am currently working on a project that involves using seismic attributes as input parameters in a neural network for estimation of porosity and permeability for a reservoir. Now, I need to correlate between well log and seismic data, so I need to learn how to interpret some special kind of images, such as this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/odzrb.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/odzrb.png&quot; alt=&quot;Image of a seismic horizon&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can someone tell me what can be interpreted from this image?&lt;/p&gt;&#xA;" OwnerUserId="12718" LastEditorUserId="28050" LastEditDate="2018-05-12T19:06:46.693" LastActivityDate="2018-05-12T19:06:46.693" Title="Interpretation of horizon display" Tags="|geology|geophysics|earthquakes|seismic|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14085" PostTypeId="1" CreationDate="2018-05-09T12:52:19.643" Score="2" ViewCount="366" Body="&lt;p&gt;In Inverse problem theory, what is meant by &quot;results of the measurements of observable parameter&quot;?&lt;/p&gt;&#xA;" OwnerUserId="11861" LastActivityDate="2018-05-09T19:00:34.220" Title="Difference between model parameter and observable parameter" Tags="|geophysics|numerical-modelling|inversion|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14086" PostTypeId="2" ParentId="14083" CreationDate="2018-05-09T13:07:33.207" Score="2" Body="&lt;p&gt;Maybe you can describe how many degrees of global warming are you trying to compare that massive meltdown.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are several nuclear waste, like the following:&#xA;Xe133, I131, Cs134, Cs137, Te132, Sr89, Sr90, Ba140, Zr95, Mo99, Ru103, Ru106, Ce141, Ce144, Np239, Pu238, Pu239, Pu240, Pu241, Cm242&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some isotopes have a short life, so they don't matter, while others might have a half life of millions of years. In fact, uranium is so stable that you can still find it in the Earth crust.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But usually, the most dangerous for health are the ones that are between some days and some years of half life, like I131 (8 days of half life), Sr90 (28.78 years) and Cs137 (30 years).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe you can give a look to &lt;a href=&quot;https://en.wikipedia.org/wiki/Chernobyl_disaster&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chernobyl case&lt;/a&gt; in order to get more info.&lt;/p&gt;&#xA;" OwnerUserId="5004" LastEditorUserId="6298" LastEditDate="2018-05-10T15:42:25.843" LastActivityDate="2018-05-10T15:42:25.843" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14087" PostTypeId="1" AcceptedAnswerId="14093" CreationDate="2018-05-09T14:55:55.940" Score="0" ViewCount="59" Body="&lt;p&gt;Am working through two problems which I am not sure if I am handling correctly.   Here they are:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;a. If the Earth decreases its distance from the sun by 0.03&#xA;  Astronomical Units (AU), what will be the resulting exoatmospheric&#xA;  flux?&lt;br&gt;&#xA;  Recall that at present the exoatmospheric flux = 1,370 $Wm^{-2}$&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My solution (use inverse square law):  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Inverse-square law:&#xA;$S = s_0(r_0/r)^2$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$S = 1370 \; (1\;AU/0.97\;AU)^2 = 1412.37\;W/m^{-2}$&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;b. Assuming   an  albedo  of  0.3, how much incoming shortwave energy will&#xA;  the   Earth absorb on average in $Wm^{-1}$?&lt;br&gt;&#xA;  Recall    that    Energy  absorbed    =   $S/4(1-A)	Wm^{-2}$&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This confuses me, the difference between $Wm^{-1}$ and $Wm^{-2}$.  What's the differences between Watts per meter to the first and watts per meter squared? Not sure how to combine the two to make the math/metrics come out right.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Going off what I have for part a:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Energy absorbed = $S/4(1-A)Wm^{-2}$&lt;br&gt;&#xA;Energy absorbed = $1412.37/4(1-0.3)Wm^{-2} = 247.17$ (is this in $Wm^{-2}$ or $Wm^{-1}$?)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="12335" LastEditorUserId="6298" LastEditDate="2018-05-10T15:17:45.780" LastActivityDate="2018-05-10T15:35:36.877" Title="Calculating exoatmosphereic flux and figuring out amount of SW Earth will absorb at an albedo of 0.3?" Tags="|atmosphere|climate-change|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14088" PostTypeId="2" ParentId="14087" CreationDate="2018-05-09T18:23:54.277" Score="0" Body="&lt;p&gt;Looking at your equations and assuming you've plugged in the right numbers everything looks right, what &lt;em&gt;doesn't&lt;/em&gt; look right is question b.; Watts per metre has no place in such an equation it just doesn't fit the question, &lt;strong&gt;all&lt;/strong&gt; the units should be expressed and calculated in square metres, and the answer you have in the last section is.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-05-09T18:23:54.277" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14089" PostTypeId="2" ParentId="14085" CreationDate="2018-05-09T19:00:34.220" Score="2" Body="&lt;p&gt;Inverse problems deal with creating theories based on observed data, as opposed to making predictions about the real world based on existing theoretical models, so the &quot;results of the measurement of observable parameter&quot; is a confusing way of saying &quot;the real measurements being used as data&quot;. Parameter simply refers to the value being measured.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An example would be if you have a forestry block and you want to understand why some trees are preforming better than others; you'd measure a whole group of variables that formed a set of parameters, one of which might be &quot;tree health&quot; based on say height, girth, leaf activity, and transpiration rate and another that's &quot;soil fertility&quot; based on key nutrient levels, particle size distribution, bulk density, and water holding capacity. The relationship between those two parameters then lets you formulate a theory that you can apply at other sites that you know the &quot;soil fertility&quot; of to predict the growth of trees there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the real world you have to test your theory with what in my GIS classes they called a &quot;Ground Truth&quot;, that's where you go out and measure the parameters of a different real world site being used for the same crop and see if your theory accounts for the results at that site (we did them to confirm the relationship between satellite readings and on-the-ground data). When you've done this at a number of sites and the measurements all conform to your theory you can start applying your model as a predictive formula for sites not yet in use.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-05-09T19:00:34.220" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14090" PostTypeId="2" ParentId="14077" CreationDate="2018-05-09T21:34:09.307" Score="2" Body="&lt;p&gt;Your best bet with something like this is find the nearest museum and bring it in, they will be familiar with the local geological artifacts. From just the photos it is hard to check for all the marks we would expect from a natural mold. As Ash said there is a chance it is just a pseudofossil but without being able to see all the internal surfaces I do not feel confident saying for sure. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2018-05-09T21:34:09.307" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14091" PostTypeId="1" AcceptedAnswerId="14114" CreationDate="2018-05-10T04:44:44.413" Score="5" ViewCount="538" Body="&lt;p&gt;&lt;a href=&quot;https://minerals.usgs.gov/minerals/pubs/commodity/lithium/&quot; rel=&quot;nofollow noreferrer&quot;&gt;According to the US Geological Survey&lt;/a&gt;, nearly all of the world's lithium reserves are in Chile/Argentina, China, and Australia. Why is this? Lithium seems to be mostly harvested from brine pools, so are these just the areas where lithium can be economically harvested, or does it represent an uneven distribution in Earth's crust?&lt;/p&gt;&#xA;" OwnerUserId="12881" LastEditorUserId="28050" LastEditDate="2018-05-12T19:01:49.297" LastActivityDate="2018-05-12T19:01:49.297" Title="Why is lithium so unevenly distributed?" Tags="|economic-geology|crust|mining|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14093" PostTypeId="2" ParentId="14087" CreationDate="2018-05-10T15:35:36.877" Score="1" Body="&lt;p&gt;Agree with &lt;a href=&quot;https://earthscience.stackexchange.com/a/14088/6298&quot;&gt;Ash&lt;/a&gt;, I think it's a mistake.  Dimensionally:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$\frac{S}{4}(1−A)$$ is going to have the units of $S$ has because $A$, &lt;a href=&quot;http://www.cocorahs-albedo.org/about/&quot; rel=&quot;nofollow noreferrer&quot;&gt;albedo, is a unitless ratio&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Insolation comes in over an area, so is measured in $W/m^2$ as you've got.  The only way I can see you'd get units of $W/m$ is by multiplying by a distance somewhere, perhaps by integrating its values over a latitudinal distance or something... but that's not really insolation (or exoatmosphereic flux as you call it!) anymore.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No, all values of S should be $W/m^2$.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2018-05-10T15:35:36.877" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14097" PostTypeId="2" ParentId="12149" CreationDate="2018-05-10T18:44:37.273" Score="0" Body="&lt;p&gt;create a bench test using an acceleramentor and a transducer since their values are known then equate the results to your sesimo&lt;/p&gt;&#xA;" OwnerUserId="12886" LastActivityDate="2018-05-10T18:44:37.273" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14099" PostTypeId="1" AcceptedAnswerId="14106" CreationDate="2018-05-10T21:04:47.347" Score="4" ViewCount="448" Body="&lt;p&gt;This is a question that has bothered me for many years.  As a new teacher I was asked this question by a 12 year old in our plate tectonics class.  I said I would go away and find out.  I would really appreciate some help!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have some understanding of plate tectonics but I struggle with understanding how the plate boundaries have changed in terms of their actual spatial positions over long periods of time.  For example, what would the 'jigsaw pattern' of plates at the time of Pangea have looked like?  At plate margins, does the pressure of compression or expansion actually change the spatial position of the margin?  &lt;a href=&quot;http://www.mantleplumes.org/WebDocuments/DLAHowManyPlates.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Anderson&lt;/a&gt; comments...&#xA;&quot;The definition of a plate and a plate boundary is subjective. Things are constantly changing. It is improbable that there is a steady state or equilibrium configuration of plates because both ridges and trenches migrate and only a few of the 16 kinds of triple junctions are stable.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This serves to confuse me further unfortunately.  I have no issues understanding how continents move around, it is the potential change to the size, shape, orientation and position of plates that baffles me!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This probably relates to the potential for new plate boundaries to be formed...and existing ones to close up.  Is this possible?  Sorry if this is an overly simple question.  If this is possible it could explain a lot.  A geologist friend told me that the East African Rift Valley is an example of a weakness in the crust that could turn into a plate margin.  If that's true that could explain a lot.  If new plates can form and existing ones disappear this would go a long way to solving my dilemma.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any views would be much appreciated and I can then give my 12 year old pupil a decent answer!&#xA;Many thanks all.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS. Just about every geography text book out there suggests plate tectonics is a result of convection currents in the mantle.  Many teachers teach this because that's what they've been taught.  I appreciate the science has moved on and now involved slab-pull and several other potential forces!  Without making it too complex, what should we be teaching 12+ year olds?&lt;/p&gt;&#xA;" OwnerUserId="12887" LastActivityDate="2018-05-11T19:53:32.753" Title="How much change has there been to the shape of plate boundaries over geological time?" Tags="|geography|tectonics|geodynamics|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14100" PostTypeId="1" AcceptedAnswerId="14102" CreationDate="2018-05-11T00:52:59.580" Score="0" ViewCount="338" Body="&lt;p&gt;Reading a news article &lt;a href=&quot;https://www.watoday.com.au/national/western-australia/probe-after-gorgon-releases-millions-of-tonnes-of-greenhouse-gas-20180510-p4zeis.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Probe after Gorgon releases millions of tonnes of greenhouse gas&lt;/a&gt;, I am confused.  CO2 is a gas, right?  Gases are not very dense, right?  So what does 5MT of the stuff look like?  How big a tank do we need to hold it?&lt;/p&gt;&#xA;" OwnerUserId="12890" LastEditorUserId="595" LastEditDate="2018-05-11T06:17:47.010" LastActivityDate="2018-05-11T06:29:45.200" Title="What does 5,000,000 tonnes of CO2 look like?" Tags="|climate-change|geochemistry|environmental-protection|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14101" PostTypeId="1" CreationDate="2018-05-11T03:21:25.687" Score="2" ViewCount="213" Body="&lt;p&gt;In my problem there is an average net ecosystem production  rate    of:&lt;/p&gt;&#xA;&lt;p&gt;0.25 kg°C/m&lt;sup&gt;2&lt;/sup&gt;/yr&lt;/p&gt;&#xA;&lt;p&gt;Am asked:&lt;/p&gt;&#xA;&lt;p&gt;a. What percentage  of  140,000 tons/yr would be offset from reforesting    45,000 acres?&lt;/p&gt;&#xA;&lt;p&gt;b. With that what area of reforestation/afforestation would need to be offset by 10% by the same emissions?&lt;/p&gt;&#xA;&lt;p&gt;How I solved (not sure if correct):&lt;/p&gt;&#xA;&lt;p&gt;Since 45,000 is in acres I converted to square meters:&lt;/p&gt;&#xA;&lt;p&gt;45,000 Acres = 182,108,539.008 m&lt;sup&gt;2&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;Then I could say for every 0.25 there would be one m&lt;sup&gt;2&lt;/sup&gt; from the above number. Therefore I multiplied.&lt;/p&gt;&#xA;&lt;p&gt;0.25*182,108,539.008 = 45,527,134.752 kg °C&lt;/p&gt;&#xA;&lt;p&gt;So now I need to convert kg to ton:&lt;/p&gt;&#xA;&lt;p&gt;45,527,134.752 kg = 50,185.08 tons&lt;/p&gt;&#xA;&lt;p&gt;So now I just need to divide into 140,000 to find how much it knocks off of the total carbon emitted:&lt;/p&gt;&#xA;&lt;p&gt;140,000 / 50,185.08 = 2.8%&lt;/p&gt;&#xA;&lt;p&gt;Is this right?&#xA;I'd imagine for 10% I'd just have to adjust the acreage to get it just right. With land area being 25,414,258,332.672 m&lt;sup&gt;2&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="12335" LastEditorUserId="2470" LastEditDate="2021-10-23T14:53:14.850" LastActivityDate="2021-10-23T14:53:14.850" Title="Trying to calculate the percentage of carbon emissions that is offset by 45,000 acres?" Tags="|climate-change|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14102" PostTypeId="2" ParentId="14100" CreationDate="2018-05-11T04:46:33.993" Score="-1" Body="&lt;p&gt;&quot;Look like&quot; is not quite right, since gaseous CO2 is transparent to visible light.  To get a sense of the volume, we can do some simple math, which unless I've made a mistake somewhere gives an area 21 km/13 miles on a side, stretching from sea level to space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Showing my work:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;x = 5 Gt =  5000000000 * 2000 lbs/ton = 10000000000000 lbs&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sea level pressure = 14.7 lbs/in^2, so 680272108843 in^2&lt;/p&gt;&#xA;&#xA;&lt;p&gt;144 in^2 per ft^2, so an area of 4724111866 ft^2, or a square 68732 ft on a side&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Convert to miles = 13 miles on a side&#xA;Convert to km = 20.9 km&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2018-05-11T04:46:33.993" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="14103" PostTypeId="1" CreationDate="2018-05-11T04:48:24.607" Score="1" ViewCount="35" Body="&lt;p&gt;I would like to know what plants, trees can be planted in a locality. I wanted this info around the globe based on latitude and longitude or by some other means. Is there a source organisation/source that maintains this data?&lt;/p&gt;&#xA;" OwnerUserId="12891" LastActivityDate="2018-05-11T04:48:24.607" Title="Where I find the info about what plants, trees can be planted in a locality" Tags="|climate-change|climate|plant|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14104" PostTypeId="2" ParentId="14100" CreationDate="2018-05-11T06:29:45.200" Score="6" Body="&lt;p&gt;The question is hard to give a definitive answer to, as it depends on the pressure at which the gas is kept in the tank. But to try to give an intuitive sense of how much gas this is, let's work out two things: Firstly, how big the box would be at atmospheric pressure; and secondly, how many standard gas bottles it would take.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;At atmospheric pressure&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The mass of one &lt;a href=&quot;https://en.wikipedia.org/wiki/Mole_(unit)&quot; rel=&quot;noreferrer&quot;&gt;mole&lt;/a&gt; of CO&lt;sub&gt;2&lt;/sub&gt; is 44 grams. So 5 MT of CO&lt;sub&gt;2&lt;/sub&gt; is $\frac{5\times 10^{12}}{44} = 114\times 10^9$ moles of gas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Ideal_gas_law&quot; rel=&quot;noreferrer&quot;&gt;ideal gas law&lt;/a&gt; tells us that&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$PV = nRT$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $P$ is pressure, $V$ is volume, $n$ is the number of moles of the gas, $R$ is a constant, and $T$ is the temperature in Kelvin. If we assume a pressure of 100,000 Pa (roughly atmospheric pressure) and a temperature of 300 K (roughly room temperature), then&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$V = \frac{nRT}{P} = \frac{114 \times 10^9 \times 8.314 \times 300}{10^5} = 2.8\times 10^9$ m&lt;sup&gt;3&lt;/sup&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That volume works out to &lt;strong&gt;a cube with sides of 1.4 km&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;In gas bottles&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;A standard large CO&lt;sub&gt;2&lt;/sub&gt; bottle of the type that is familiar in the UK looks like the one on the right of this picture:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PbnJ5.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PbnJ5.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and &lt;a href=&quot;https://www.boconline.co.uk/internet.lg.lg.gbr/en/images/Carbon-Dioxide-factsheet410_54560.pdf?v=2.0&quot; rel=&quot;noreferrer&quot;&gt;according to BOC&lt;/a&gt; contains 34 kg of gas, at a pressure of up to 50 bar. So that's 29.4 cylinders per tonne or, to contain 5 million tonnes of CO&lt;sub&gt;2&lt;/sub&gt;, &lt;strong&gt;147 million of these cylinders.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2018-05-11T06:29:45.200" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14106" PostTypeId="2" ParentId="14099" CreationDate="2018-05-11T08:04:10.430" Score="3" Body="&lt;p&gt;I am not sure if you are actually asking about Tectonic Plate boundaries, or the boundaries of continents, which are often described a puzzle pieces when teaching continental drift due to the way continents like South America and Africa fit together. I'm going to try and address both possibilities. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tectonic Plate boundaries are constantly changing. Many of the edges of tectonic boundaries are thin freshly-formed oceanic crust which isn't going to put up much of a fight. You know about subduction so you understand that oceanic crust is constantly 'recycled'. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The present day amount of continental crust on earth hasn't existed for all of earth's history. Current thinking is that it has been been accumulated overtime (&lt;a href=&quot;https://serc.carleton.edu/NAGTWorkshops/earlyearth/questions/crust.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;theories differ as to how quickly&lt;/a&gt;), through a &lt;a href=&quot;https://www.scientificamerican.com/article/the-evolution-of-continental-crust-2005-07/&quot; rel=&quot;nofollow noreferrer&quot;&gt;number of processes which have built up the present level of continental crust&lt;/a&gt; that is more buoyant that the mantel and oceanic crust and thus resistant to subduction. As a result the size and shape of the continents have been slowly changing and growing over earth's history as they gain new bits, join and split. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;For example, what would the 'jigsaw pattern' of plates at the time of Pangea have looked like?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;this video shows continents moving around, growing and joining and how they change over time, at least for the last 1.5 billion years of earth's 4.5 billion history. Pangea was around from 335Ma to 175Ma, you can see it form and break up in the video.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=IlnwyAbczog&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=IlnwyAbczog&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This probably relates to the potential for new plate boundaries to be&#xA;  formed...and existing ones to close up. Is this possible?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In this video blue and red lines show active tectonic plate boundaries.&#xA;you can see that they change. They move around, old ones stop and new ones start. They even change from divergent to convergent or consume each other.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;At plate margins, does the pressure of compression or expansion actually change the spatial position of the margin?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Absolutely. at the end of the video watch India slam into Asia and create the Himalayas as a result.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not an education specialist, but i have seen videos like these be used to explain the processes to kids.&lt;/p&gt;&#xA;" OwnerUserId="12892" LastEditorUserId="7080" LastEditDate="2018-05-11T12:52:31.097" LastActivityDate="2018-05-11T12:52:31.097" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14107" PostTypeId="1" AcceptedAnswerId="14120" CreationDate="2018-05-11T14:16:11.810" Score="8" ViewCount="440" Body="&lt;p&gt;In a conversation in comments below &lt;a href=&quot;https://space.stackexchange.com/a/27199/12102&quot;&gt;this answer&lt;/a&gt; to the question in Space Exploration &lt;a href=&quot;https://space.stackexchange.com/q/27193/12102&quot;&gt;Could we see the surface of Venus after the explosion of a H-bomb in its atmosphere?&lt;/a&gt; we're speculating about what terms like sulfuric clouds and sulfuric haze mean, and in particular if they are both made of aerosols based on water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What might be the difference between sulfuric clouds and sulfuric haze, and do both still require water in the form of an aerosol?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nbWK2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nbWK2.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2018-05-12T15:29:31.210" LastActivityDate="2018-10-11T08:22:23.030" Title="Difference between sulfuric clouds and sulfuric haze (on Venus)?" Tags="|atmosphere|clouds|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="14109" PostTypeId="2" ParentId="14099" CreationDate="2018-05-11T16:37:28.290" Score="0" Body="&lt;p&gt;uneven heating and cooling of the earths core cause the plates to move in all directions. this is not unlike the same way the sun alters our weather. however one must think in 3 dimensions to determine what influences what - afterall everything is connected and constantly moving. Example  home owner had a roof leak. so he kept replacing the shingles directly above the leak  - still kept leaking. contractor had to replace the entire roof and determined that the leak was actually 25 ft away  &lt;/p&gt;&#xA;" OwnerUserId="12886" LastActivityDate="2018-05-11T16:37:28.290" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14114" PostTypeId="2" ParentId="14091" CreationDate="2018-05-12T01:05:40.120" Score="4" Body="&lt;p&gt;The term &quot;reserves&quot; doesn't mean what most people think it does.  A mineral &lt;em&gt;deposit&lt;/em&gt; is simply a concentration of a mineral; a &lt;em&gt;reserve&lt;/em&gt; is a &lt;em&gt;deposit&lt;/em&gt; that is both known and economical to extract.  As an example, oil shale and tar sands have both been known for decades, but only recently became oil reserves as improving technology and rising prices made it practical to extract the crude oil from them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Chile, Argentina, Australia, and China have quantified their deposits, and local economic/geologic conditions make it profitable to extract those deposits, so they've got most of the world's reserves.&lt;/p&gt;&#xA;" OwnerUserId="2643" LastActivityDate="2018-05-12T01:05:40.120" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14115" PostTypeId="2" ParentId="14091" CreationDate="2018-05-12T03:40:23.860" Score="4" Body="&lt;p&gt;Start by reading my answer on a different website:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://chemistry.stackexchange.com/a/96630/8083&quot;&gt;https://chemistry.stackexchange.com/a/96630/8083&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a quick explainer on what &quot;reserves&quot; actually are.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Lithium is mined from two main sources: a type of granitic rock called &quot;&lt;a href=&quot;https://geology.com/rocks/pegmatite.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;pegmatite&lt;/a&gt;&quot;, and brine pools.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pegmatites are rare rocks, and lithium-rich pegmatites are even rarer and you don't find them in a lot of places. Even when you do, they are most likely not included in the &quot;reserves&quot; because there is no extraction infrastructure, know-how, or economic drive to produce lithium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lithium-rich brines only form when you have evaporite lakes in dry regions, that also happen to have pegmatites, granites, and other lithium-rich rocks nearby. This commonly occurs in South America because there are deserts and plenty of granites. In contrast, the Dead Sea (Israel/Jordan) is one of the most saline lakes in the world, but it has very little lithium in it because the nearby rocks are limestones, not granites.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-05-12T03:40:23.860" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14116" PostTypeId="1" AcceptedAnswerId="14119" CreationDate="2018-05-12T03:47:20.760" Score="0" ViewCount="289" Body="&lt;p&gt;Australian animals are very different than the rest of the world. I wonder if the radiation of Australia's Uranium deposits have anything to do with why animals uniquely evolved? For instance, marsupials have three vaginas and platypus are one of the only mammals that lay eggs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If not Uranium what makes them so different?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://list25.com/25-outrageous-kangaroo-facts-to-keep-your-mind-hopping/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://list25.com/25-outrageous-kangaroo-facts-to-keep-your-mind-hopping/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2018-05-12T16:07:49.680" LastActivityDate="2020-07-22T17:13:16.133" Title="Is there any correlation between Australia's uranium deposits and the unique animals?" Tags="|geography|radioactivity|uranium|evolution|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14118" PostTypeId="2" ParentId="14116" CreationDate="2018-05-12T10:41:06.983" Score="5" Body="&lt;p&gt;No. The reason for Australia’s unique evolution is that it was relatively isolated from the rest of the world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Australia isn’t too radioactive either. The fact that it has more uranium deposits than other countries is that it’s huge.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-05-12T10:41:06.983" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14119" PostTypeId="2" ParentId="14116" CreationDate="2018-05-12T10:41:08.673" Score="3" Body="&lt;p&gt;Ahhhh, probably not.  If, for example, you navigate to &lt;a href=&quot;https://en.wikipedia.org/wiki/Marsupial&quot; rel=&quot;nofollow noreferrer&quot;&gt;Marsupial&lt;/a&gt; at Wikipedia and click on the wonderful (it really really is!) DyMaxion map at the bottom of the info panel, you wiil see that a large part of South America, Central and North America also have these animals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;FWIW, the USA does indeed have Uranium deposits although I'm not sure about Central and South America.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quoting from Wikipedia:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A 2010 analysis of retroposon insertion sites in the nuclear DNA of a variety of marsupials has confirmed all living marsupials have South American ancestors.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;South America was connected to Antarctica for a long time (but not to North America), as was Australia.&lt;/p&gt;&#xA;" OwnerUserId="12890" LastActivityDate="2018-05-12T10:41:08.673" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14120" PostTypeId="2" ParentId="14107" CreationDate="2018-05-12T17:18:40.363" Score="4" Body="&lt;p&gt;According to Wikipedia, &lt;a href=&quot;https://en.wikipedia.org/wiki/Haze&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;haze&lt;/strong&gt;&lt;/a&gt; is an atmospheric phenomenon in which dry particulates obscure the clarity of the sky.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whereas haze is thought of as a phenomenon of dry air, mist formation is a phenomenon of humid air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, haze particles may act as condensation nuclei for the subsequent formation of mist droplets; such forms of haze are known as &quot;wet haze&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In meteorological literature, the word haze is generally used to denote visibility-reducing aerosols of the &lt;strong&gt;wet&lt;/strong&gt; type.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to Wikipedia, &lt;a href=&quot;https://en.wikipedia.org/wiki/Cloud&quot; rel=&quot;nofollow noreferrer&quot;&gt; &lt;strong&gt;a cloud&lt;/strong&gt;&lt;/a&gt; is an aerosol with a &lt;strong&gt;visible&lt;/strong&gt; mass of liquid droplets, frozen crystals or particals suspended in the atmosphere, and the droplets &lt;strong&gt;don't have to be made of water.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.hou.usra.edu/meetings/venus2014/pdf/6005.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; states that standard cloud models for Venus consider that all clouds and hazes are composed of liquid droplets of sulfuric acid mixed with water, with sulfuric acid making accounting for 75% to 96% by weight of the cloud composition.&#xA;However, other minor constituents may make up the cloud particles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Clearly regarding the mixture of water and sulfuric acid there is no distinction between clouds and hazes on Venus.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In &lt;a href=&quot;https://www.lpi.usra.edu/vexag/meetings/archive/vexag_4th/nov_2007/presentations/toon.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;another article&lt;/a&gt; it can be seen on images that the altitude from 30-48 km of the atmosphere of Venus is named &quot;the thin haze region &quot;, whereas&#xA;the altitude from 48-50 km is called &quot;lower cloud region &quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The figure on page 14 of &lt;a href=&quot;https://www.mps.mpg.de/phd/theses/venus-cloud-structure-and-radiative-energy-balance-of-the-mesosphere.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;the dissertation of Yeon Joo Lee&lt;/a&gt; also shows that below the cloud layers there is this &quot;thin haze region&quot; which has almost a thousandfold less &lt;a href=&quot;https://en.wikipedia.org/wiki/Extinction_coefficient&quot; rel=&quot;nofollow noreferrer&quot;&gt;extinction coëfficiënt&lt;/a&gt; than the clouds above it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Apparently this huge difference in absorbing the light explains the difference and appearance between sulfuric clouds and sulfuric haze on Venus.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Figure 4 of Bullock and Grinspoon 2001 (paywalled) &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0019103500965709&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Recent Evolution of Climate on Venus&lt;/a&gt; (Icarus 150, 1, Mar. 2001, pp 19-37) shows the abundances of H&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;SO&lt;span class=&quot;math-container&quot;&gt;$_4$&lt;/span&gt; and H&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;O in the cloud region of the atmosphere of Venus. A non-paywalled version can be found with an internet search, but since it does not use https I won't include the link explicitly here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wqRfx.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wqRfx.png&quot; alt=&quot;Fig 4 Bullock &amp;amp; Grinspoon 2001 Venus aerosols&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Explicitely it shows H&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;SO&lt;span class=&quot;math-container&quot;&gt;$_4$&lt;/span&gt; as a gas in the thin haze region and only in the cloud region there is a mixture of water and sulfuric acid liquid.&lt;/p&gt;&#xA;" OwnerUserId="12903" LastEditorUserId="12903" LastEditDate="2018-10-11T08:22:23.030" LastActivityDate="2018-10-11T08:22:23.030" CommentCount="18" ContentLicense="CC BY-SA 4.0" />
  <row Id="14122" PostTypeId="1" CreationDate="2018-05-12T23:28:57.420" Score="1" ViewCount="22" Body="&lt;p&gt;How much mass (either absolute or relative to the Earth) was [estimate to have been] added to the Earth during the Late Heavy Bombardment?&lt;/p&gt;&#xA;" OwnerUserId="11964" LastActivityDate="2018-05-12T23:28:57.420" Title="Mass contribution during the LHB" Tags="|earth-history|meteorite|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14124" PostTypeId="1" CreationDate="2018-05-13T05:59:49.990" Score="1" ViewCount="31" Body="&lt;p&gt;I'm currently doing a question at the moment which is:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Evaluate the usefulness and limitations of evidence provided by meteorites of Earth's age.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm having trouble finding some limitations at the moment if anyone could help that would be appreciated, thanks!&lt;/p&gt;&#xA;" OwnerUserId="12907" LastEditorUserId="725" LastEditDate="2018-05-13T07:24:11.277" LastActivityDate="2018-05-13T07:24:11.277" Title="what are some limitations for using meteorites as evidence for the Earth's age?" Tags="|homework|meteorite|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14126" PostTypeId="1" CreationDate="2018-05-13T11:35:16.443" Score="1" ViewCount="53" Body="&lt;p&gt;We all know that global climate change is becoming a big real change that is affecting the world's ecosystems and life cycles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Will global climate change affect the hot areas of the world or deserts like the UAE, Oman, Sahara desert etc.?&lt;/p&gt;&#xA;" OwnerUserId="12910" LastEditorUserId="5594" LastEditDate="2018-05-14T08:55:01.023" LastActivityDate="2018-05-14T08:55:01.023" Title="Global climate change" Tags="|climate-change|desert|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14127" PostTypeId="1" CreationDate="2018-05-13T11:39:25.943" Score="4" ViewCount="174" Body="&lt;p&gt;What I want to know is more specific than the title: If a city sits on major fault lines (let's say Tehran), and has a history of severe earthquakes (greater than 7 magnitude) once every 150 years in average, does the probability of &quot;a severe earthquake within the next year&quot; increase as more and more time is passed since the last severe earthquake? &lt;/p&gt;&#xA;" OwnerUserId="12909" LastEditorUserId="12909" LastEditDate="2018-05-13T13:36:16.083" LastActivityDate="2018-05-13T13:36:16.083" Title="Is the probability distribution of earthquakes memoryless?" Tags="|earthquakes|statistics|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14130" PostTypeId="1" CreationDate="2018-05-13T12:16:31.853" Score="1" ViewCount="24" Body="&lt;p&gt;Is there any way to get barometric time series for regions of the United States? I know that barometric maps are widely available, but in my case I want to see a time series for one region. However, I have not found any comprehensive source for weather time series data including pressure readings. Does that exist?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2018-05-13T12:16:31.853" Title="Get barometric data?" Tags="|open-data|barometric-pressure|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14132" PostTypeId="1" AcceptedAnswerId="14134" CreationDate="2018-05-13T18:01:56.410" Score="4" ViewCount="563" Body="&lt;p&gt;Using the site &lt;a href=&quot;https://www.antipodesmap.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;antipodesmap&lt;/a&gt; one can quickly explore what the opposite point of the earth to any location would be. That is, the surface point connected to this point by a straight line through the centre of the earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is easy to see that &lt;em&gt;most&lt;/em&gt; land points have antipodes which lie somewhere in water, which made me wonder:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How much land area (as a fraction of total land area) has antipodal land area?&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;And how would I best find this out? Can somebody produce a map of those areas, e.g. highlight those areas on a world map?&lt;/p&gt;&#xA;" OwnerUserId="1334" LastEditorUserId="28050" LastEditDate="2018-05-15T11:26:50.543" LastActivityDate="2018-05-15T11:26:50.543" Title="How much of Earth's land area has antipodal land area?" Tags="|geography|mapping|cartography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14133" PostTypeId="1" CreationDate="2018-05-13T19:18:19.060" Score="7" ViewCount="110" Body="&lt;p&gt;The most powerful volcanic eruption in recorded history was the 1815 eruption of Mount Tambora, an explosion equivalent to &lt;a href=&quot;https://www.wired.com/2015/04/tambora-1815-just-big-eruption/&quot; rel=&quot;noreferrer&quot;&gt;33 billion tons of TNT&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any way a cryovolcanic eruption could be as large as this? I couldn't find a source on how powerful a typical eruption is, but based on the low temperatures, I can guess that they're small. However, in a hypothetical moon where there is much stronger tidal friction than we see in the Solar System, I think the eruptions can become much larger.&lt;/p&gt;&#xA;" OwnerUserId="12912" LastActivityDate="2024-01-08T15:55:38.530" Title="Can a cryovolcanic eruption be as powerful as a normal volcanic eruption?" Tags="|volcanology|planetary-science|volcanic-eruption|planetology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14134" PostTypeId="2" ParentId="14132" CreationDate="2018-05-13T20:41:41.993" Score="8" Body="&lt;p&gt;A rough idea, using the Lambert Conformal image at the &lt;a href=&quot;http://scitools.org.uk/cartopy/docs/v0.15/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cartopy projection list&lt;/a&gt; and Gimp:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Dxmj9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Dxmj9.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The gold area should be the overlap.  So basically parts of South America with Indonesia and SE Asia... and Antarctica with the far northern islands of the northern hemisphere, plus a few smaller areas from islands like New Zealand and Hawaii and even smaller.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That assumes I did properly invert it.  To do so, I just vertically flipped the image, and offset it by 180 degrees.  Thinking that should be all that is needed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in the end it looks like it's not a lot of area at all.  Further exact statistics would take some GIS work (probably quicker than GIMP in the end!)  A central starting guess would be 8.5% (the 29% land cover squared), but particulars will make it a bit higher or lower.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="87" LastEditDate="2018-05-15T09:23:08.027" LastActivityDate="2018-05-15T09:23:08.027" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="14135" PostTypeId="1" CreationDate="2018-05-14T02:07:54.767" Score="3" ViewCount="355" Body="&lt;p&gt;I am in the middle of a hobbyist experiment and would like suggestions on an open source HTML viewer for mud loggging, FMIs, lithology and seismic. I have used INT before but for this project I would like an open source alternative.&lt;/p&gt;&#xA;" OwnerUserId="12913" LastEditorUserId="28050" LastEditDate="2018-05-15T11:21:08.520" LastActivityDate="2018-11-03T06:57:52.570" Title="Open source well information viewer" Tags="|geology|geophysics|seismology|seismic|software|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14140" PostTypeId="1" AcceptedAnswerId="14156" CreationDate="2018-05-14T08:11:18.753" Score="0" ViewCount="89" Body="&lt;p&gt;Satellite retrievals contain cloud cover, biases e.t.c which is the main challenge to prepare the data for further analysis. &#xA;After all, how we can efficiently calculate the snow cover and its temporal change in any language base platform from satellite  data? &lt;/p&gt;&#xA;" OwnerUserId="12714" LastActivityDate="2018-05-15T06:53:57.643" Title="How to calculate the snow cover area from satellite data in better and efficient way?" Tags="|precipitation|snow|satellites|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14141" PostTypeId="1" AcceptedAnswerId="14142" CreationDate="2018-05-14T08:28:43.493" Score="2" ViewCount="81" Body="&lt;p&gt;Everyone surely enjoys waves in the beach, but one question that has always been hovering around my head was about the wnd.&#xA;I have always been told that waves are formed by wind and all, but then where  does the wind come from? &lt;/p&gt;&#xA;" OwnerUserId="12910" LastActivityDate="2018-05-14T08:55:36.773" Title="How is wind made" Tags="|ocean|wind|waves|" AnswerCount="1" CommentCount="0" ClosedDate="2018-05-14T12:51:34.230" ContentLicense="CC BY-SA 4.0" />
  <row Id="14142" PostTypeId="2" ParentId="14141" CreationDate="2018-05-14T08:55:36.773" Score="4" Body="&lt;p&gt;Wind is produced by a pressure difference between two places. Air molecules move from higher pressure region to lower pressure region, this movement of air molecules is known as wind. &lt;/p&gt;&#xA;" OwnerUserId="10780" LastActivityDate="2018-05-14T08:55:36.773" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14143" PostTypeId="2" ParentId="13963" CreationDate="2018-05-14T08:56:15.993" Score="1" Body="&lt;p&gt;I just read an article saying that algae produces more oxygen than all the plants in the world!!&#xA;Edit: &lt;a href=&quot;https://www.nps.gov/romo/learn/nature/algae.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nps.gov/romo/learn/nature/algae.htm&lt;/a&gt;       First paragraph last lines &lt;/p&gt;&#xA;" OwnerUserId="12910" LastEditorUserId="12910" LastEditDate="2018-05-15T06:14:56.610" LastActivityDate="2018-05-15T06:14:56.610" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14151" PostTypeId="1" AcceptedAnswerId="14152" CreationDate="2018-05-14T23:08:31.990" Score="2" ViewCount="173" Body="&lt;p&gt;I applied EOF (&lt;a href=&quot;https://en.wikipedia.org/wiki/Empirical_orthogonal_functions&quot; rel=&quot;nofollow noreferrer&quot;&gt;Empirical Orthogonal Function&lt;/a&gt;, a type of Principal Component Analysis, &lt;a href=&quot;https://en.wikipedia.org/wiki/Principal_component_analysis&quot; rel=&quot;nofollow noreferrer&quot;&gt;PCA&lt;/a&gt;) analysis to a dataset(geopotential height at 925hpa from ECMWF-interim reanalysis data) that contains 3 coordinates (time, longitude, latitude). Moreover, spatial field data at each time level was defined as sample or origin pattern. The results of the EOF showed that the first 4 PCs can explain 95% of the variance. How can I classify the sample or origin patterns into different PCs? In other words, which PC is similar to the origin patterns mostly?&lt;/p&gt;&#xA;" OwnerUserId="11846" LastEditorUserId="11846" LastEditDate="2018-05-16T13:59:07.707" LastActivityDate="2018-05-17T06:07:45.257" Title="How to know to which PC (Principal Component) a sample belongs in EOF/PCA" Tags="|meteorology|statistics|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14152" PostTypeId="2" ParentId="14151" CreationDate="2018-05-15T01:01:17.203" Score="3" Body="&lt;p&gt;I recommend you read &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/2009JCLI3062.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Monahan et al. (1990)&lt;/a&gt; for a thorough explanation of Empirical Orthogonal Functions. I suggest you pay attention to the way the principal components are extracted. Ultimately, there is no guarantee that a sample belongs to a specific component. What you are working with is eigenvalues/eigenvectors and thus a specific data point can have influences from multiple components. The EOF provides a time series of eigenvalues for each component. The larger the eigenvalue for that component at a specific time, the more that component explains the data point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If what you need is to assign a data point to a component, I would recommend a cluster analysis instead. For instance &lt;a href=&quot;https://www.nonlin-processes-geophys.net/14/73/2007/npg-14-73-2007.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Smith &amp;amp; Aretxabaleta (2007)&lt;/a&gt; present an improved methodology to separate regimes that outperforms the EOF analysis in an ENSO-influenced dataset.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2018-05-15T01:37:18.687" LastActivityDate="2018-05-15T01:37:18.687" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="14153" PostTypeId="1" AcceptedAnswerId="14154" CreationDate="2018-05-15T04:58:19.520" Score="3" ViewCount="148" Body="&lt;p&gt;I snapped this photo with my cell phone at a fishing harbor in northern Taiwan.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I recognize a weather vane + anemometer, and I suspect the two large, dark things at the tops of poles might be omnidirectional antennas, but the item near the right shaped like an upside-down funnel at the end of a u-shaped tube appeared to be transparent, as if glass or plastic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've never seen anything like it. Any thoughts?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KAphg.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KAphg.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2Xu8W.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2Xu8W.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T20:50:45.533" LastActivityDate="2019-08-28T20:50:45.533" Title="What is this upside-down transparent funnel-shaped item on a weather monitoring station?" Tags="|terminology|instrumentation|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14154" PostTypeId="2" ParentId="14153" CreationDate="2018-05-15T06:12:12.797" Score="6" Body="&lt;p&gt;The upside down funnel-shaped attachment is used to prevent rain-water getting inside the inlet of instruments which analyse ambient air. Usually, these instruments are air pollution monitoring instruments like ozone analyser, carbon monoxide analyser, particle concentration analyser, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One may think why can't just use U-shaped tube (inlet). In case of U-shaped inlet, rainwater falling on inlet will eventually roll down near the entrance and will be pulled in with air due to strong flow. Funnel shape will have smaller flow near the wider opening and prevents water from getting into the air stream. &lt;/p&gt;&#xA;" OwnerUserId="10780" LastActivityDate="2018-05-15T06:12:12.797" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14156" PostTypeId="2" ParentId="14140" CreationDate="2018-05-15T06:53:57.643" Score="1" Body="&lt;p&gt;Identification of snow in satellite images is done using multiwavelength measurements and including ancillary information. Snow obviously has far more reflectivity compared to barren soil, water or vegetation and any edge identification algorithm on visible channel images will identify their extent. The biggest trouble comes from clouds which can appear as bright as snow in visible channel images. Satellite measurements in the infrared region of spectrum help in the discriminate snow vs cloud. Infrared emissions of an object depend on temperature and clouds being at a higher altitude has far less temperature compared to snow. The algorithm may use other information also, for example, day to day variability. Clouds have a very short lifetime and display large variability whereas snow/ice disappears far slowly compared to cloud. &lt;/p&gt;&#xA;" OwnerUserId="10780" LastActivityDate="2018-05-15T06:53:57.643" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14158" PostTypeId="2" ParentId="14135" CreationDate="2018-05-15T11:20:36.020" Score="2" Body="&lt;p&gt;&lt;strong&gt;Your best bet is probably &lt;a href=&quot;https://dgbes.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;OpendTect&lt;/a&gt;.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's not quite what you asked for. OpendTect is a desktop application and does not use HTML/JavaScript for display. It is dual licensed; the free version is licensed under the GPL. It will read wells and seismic no problem, but I'm not sure about FMI in the free version.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Agile started &lt;a href=&quot;https://github.com/agile-geoscience/g3&quot; rel=&quot;nofollow noreferrer&quot;&gt;G3.js&lt;/a&gt;, a JavaScript library based on D3.js for logs and seismic, but we didn't get very far. (I'm the founder of Agile; I'd welcome a reason to start that project up again.) Agile also has &lt;a href=&quot;https://github.com/agile-geoscience/welly&quot; rel=&quot;nofollow noreferrer&quot;&gt;welly&lt;/a&gt;, a Python library for well logs and lithology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are lists of other open source tools for &lt;a href=&quot;https://en.wikipedia.org/wiki/Comparison_of_free_geophysics_software&quot; rel=&quot;nofollow noreferrer&quot;&gt;geophysics&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_free_geology_software&quot; rel=&quot;nofollow noreferrer&quot;&gt;geology&lt;/a&gt; on Wikipedia.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2018-05-15T11:20:36.020" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14160" PostTypeId="1" CreationDate="2018-05-15T14:11:29.850" Score="3" ViewCount="52" Body="&lt;p&gt;If I have seismic data obtained with an explosive source (i.e. minimum phase wavelet), should I re-process the data into zero-phase data to perform an acoustic impedance inversion?&lt;/p&gt;&#xA;" OwnerUserId="12924" LastEditorUserId="28050" LastEditDate="2018-05-15T14:18:17.503" LastActivityDate="2018-05-15T14:18:17.503" Title="Which wavelet for acoustic inversion?" Tags="|seismic|inversion|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14161" PostTypeId="1" CreationDate="2018-05-15T14:43:45.917" Score="3" ViewCount="70" Body="&lt;p&gt;I intend to create a long term melt record on a glacier surface. What are parameters required to efficiently calculate the same using satellite, weather station observations &amp;amp; reanalysis datasets (&lt;strong&gt;ERA-INTERIM&lt;/strong&gt;)? I need the record to be of at least 100 years &amp;amp; therefore any or a combination of these datasets needs to be used for the same!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have three cores from coastal Antarctica,  which have frequent melt layers.  I intend to calculate the melting that has happened at the surface in the past by using various climatic parameters (reanalysis data sets)  and satellite data (e.g. Microwave Datasets)  to quantify &amp;amp; /or ascertain a melting event at a certain point of time! &lt;/p&gt;&#xA;" OwnerUserId="11360" LastEditorUserId="11908" LastEditDate="2019-03-14T01:04:14.317" LastActivityDate="2019-03-14T01:04:14.317" Title="Quantifying long term melt record on glacier surface" Tags="|climate-change|glaciology|reanalysis|weather-satellites|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="14163" PostTypeId="1" AcceptedAnswerId="14171" CreationDate="2018-05-15T17:51:32.580" Score="3" ViewCount="613" Body="&lt;p&gt;How to differentiate between a rock and a mineral by merely looking at it as a thumb rule?&lt;/p&gt;&#xA;" OwnerUserId="12916" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T21:13:05.670" LastActivityDate="2019-08-28T21:13:05.670" Title="Differentiate a rock and mineral" Tags="|rocks|mineralogy|minerals|petrology|homework|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14164" PostTypeId="1" CreationDate="2018-05-15T18:08:08.793" Score="1" ViewCount="45" Body="&lt;p&gt;Which climate is easier to be predicted. In other words. Which climate forecast results better accuracy? &#xA;Is there any climate more convenient to be predicted? Is there any paper concerning this topic?&lt;/p&gt;&#xA;" OwnerUserId="12928" LastActivityDate="2018-05-15T18:08:08.793" Title="Forecast accuracy in different climate types" Tags="|climate|weather-forecasting|predictability|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14165" PostTypeId="1" CreationDate="2018-05-15T19:46:57.017" Score="1" ViewCount="83" Body="&lt;p&gt;I need to study low frequency range of seismic waves (~ up to 0.07Hz). Is it correct to use accelerometers data to compare with synthetic seismograms. Synthetic seismograms are calculated up to 0.07Hz. I found several explanations, that accelerometers data in mostly for high frequencies? Or should I mostly consider broad-band and long period seismometers for my case?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example here &quot;senses&quot; of different instruments I found:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jc6tH.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jc6tH.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12930" LastEditorUserId="5594" LastEditDate="2018-05-15T20:58:27.067" LastActivityDate="2018-05-15T20:58:27.067" Title="Applicable seismometers data?" Tags="|earthquakes|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14167" PostTypeId="1" CreationDate="2018-05-15T23:16:26.030" Score="3" ViewCount="58" Body="&lt;p&gt;This might fit better on another SX site, but thought I'd ask the science majors first.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My community has single-bin recycling. Most consumer-level metal, plastic, and paper can go in there to be sorted at a recycling center. They don't take plastic grocery bags, cellophane, paper towels, and pizza boxes. Most of these I can recycle at a more specialized location if I'm feeling like a good citizen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So most of garbage is food, paper towels, and cellophane.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm researching composting, and it seems like the only &quot;organic&quot; things I can't compost are cooked meat and dairy products. A site I'm reading mentions &quot;some paper&quot;. Maybe that means paper towels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But what I'm wondering is, what would be left after disposing of everything I can using the above methods? I get that this is a question with technically an unbounded answer. The sites I've read so far say something like &quot;everything else!&quot; I get that. But what do most people regularly consume and dispose of that wouldn't go in the &quot;trash&quot; bin if they had bins for trash, recycling, compost?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first thing that jumps to mind is batteries, but those shouldn't be thrown in the trash if we followed their instructions. Big items like old computers or broken chairs (or whatever) don't normally go in the bin, and generally have better options for getting rid of them (donations, etc.).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if I'm doing the &lt;em&gt;mostly&lt;/em&gt; bare minimum but still following the basic rules on all of the above, what would be left? Dirty diapers and greasy pizza boxes and blocks of cheese that went bad?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I feel like I must be forgetting something obvious.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;" OwnerUserId="12932" LastEditorUserId="4789" LastEditDate="2018-05-16T15:23:58.777" LastActivityDate="2018-05-16T15:23:58.777" Title="What isn't recyclable or compostable?" Tags="|environmental-protection|" AnswerCount="0" CommentCount="7" ClosedDate="2018-05-17T05:01:14.313" ContentLicense="CC BY-SA 4.0" />
  <row Id="14168" PostTypeId="1" AcceptedAnswerId="14191" CreationDate="2018-05-16T03:15:58.030" Score="20" ViewCount="15841" Body="&lt;p&gt;I remember Journey to the Center of Earth and wonder: What is the deepest in the Earth surface or below sea level we have traveled either by foot, sub, drill or camera? &lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorDisplayName="user12525" LastEditDate="2019-04-22T13:57:45.730" LastActivityDate="2019-06-02T11:58:55.217" Title="What is the deepest we have ever gone into the Earth?" Tags="|geography|mantle|crust|mining|cavern|" AnswerCount="4" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="14169" PostTypeId="2" ParentId="14168" CreationDate="2018-05-16T04:11:15.440" Score="31" Body="&lt;p&gt;Probably a bit over 4 km, in this South African mine: &lt;a href=&quot;https://en.wikipedia.org/wiki/Mponeng_Gold_Mine&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Mponeng_Gold_Mine&lt;/a&gt;  But as the link mentions, the mine operators go to considerable lengths to reduce the mine temperature to endurable levels from the  66°C/151°F of the surrounding rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: This answer is for the original question, where the OP asked for the deepest depth below the surface.  It's since been changed to ask for depth below sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VwkFT.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VwkFT.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://cracked.tumblr.com/post/162183647834/the-mponeng-gold-mine-in-south-africa-is-the&quot; rel=&quot;noreferrer&quot;&gt;http://cracked.tumblr.com/post/162183647834/the-mponeng-gold-mine-in-south-africa-is-the&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1401" LastEditorUserId="5052" LastEditDate="2018-05-18T08:22:47.930" LastActivityDate="2018-05-18T08:22:47.930" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14171" PostTypeId="2" ParentId="14163" CreationDate="2018-05-16T12:41:08.117" Score="3" Body="&lt;p&gt;If you see more than one mineral you frequently can call it rock, but not always. You could have a gem incrusted into another mineral or rock.&lt;/p&gt;&#xA;&lt;p&gt;You need to know each rock uses to have one or more mineral -by definition-, but there are monomineral rocks as limestones, wich can be only composed by calcite.&#xA;If you give me a limestone I could say I have a rock, and I see also calcite, normaly with a magnifying glass.&lt;/p&gt;&#xA;&lt;p&gt;When we are searching for minerals or thinking on minerals, we use to search for well formed species. If you see a big cristal, you can affirm it is a mineral. Sometimes they are twinned. If you see an aggregate of little minerals, most times you have a rock independently if it has one or more mineral types but not all times again.&lt;/p&gt;&#xA;&lt;p&gt;What characterizes a rock at surface uses to be &lt;a href=&quot;https://en.wikipedia.org/wiki/Diagenesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;diagenesis&lt;/a&gt; -compaction of minerals- if the rock is sedimentary. Igneous and metamorphic rocks are also well formed mineral aggregates, consistent bodies.&lt;/p&gt;&#xA;&lt;p&gt;Sedimentary rocks have a lot of minerals/mineraloids cemented by a kind of microcrystaline matrix -that are also minerals crystallographically talking!-.&lt;/p&gt;&#xA;&lt;p&gt;Igneous and metamorphic rocks are compact bodies were there is a texture, minerals have textural relation (some kind of order).&lt;/p&gt;&#xA;&lt;p&gt;If you are at an ore, you could be confused again if you don't know basis concepts. You then could think the aggregates of minerals are rocks, wich is not the case. Then you have an aggregate of well formed minerals, wich is not the same as a rock.&lt;/p&gt;&#xA;&lt;p&gt;There are several definitions of rock and mineral. I took this ones:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Rock&lt;/strong&gt;:&amp;quot;mineral matter of variable composition, consolidated or&#xA;unconsolidated, assembled in masses or considerable quantities in&#xA;nature, as by the action of heat or water.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Mineral&lt;/strong&gt;:&amp;quot;any of a class of substances occurring in nature, usually&#xA;comprising inorganic substances, as quartz or feldspar, of definite&#xA;chemical composition and usually of definite crystal structure, but&#xA;sometimes also including rocks formed by these substances as well as&#xA;certain natural products of organic origin, as asphalt or coal.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;source: &lt;a href=&quot;http://www.dictionary.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.dictionary.com&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user12525" LastEditorUserId="-1" LastEditorDisplayName="user12525" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-05-17T12:22:51.660" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14172" PostTypeId="1" AcceptedAnswerId="14179" CreationDate="2018-05-16T13:11:34.743" Score="2" ViewCount="849" Body="&lt;p&gt;In various atmospheric equations, surface pressure is one of the variables used. For example, in calculating the density of air or pressure-corrected relative optical air mass. How is surface pressure measured? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I imagine it's the pressure at the height of a sensor on a weather station. Is that considered effectively pressure at Earth's surface / a good-enough approximation, or do scientists generally adjust measurements from weather stations to be corrected for the height difference between the sensor and Earth's surface? Or is surface pressure measured by a sensor actually at Earth's surface?&lt;/p&gt;&#xA;" OwnerUserId="4789" LastActivityDate="2018-05-18T01:09:27.147" Title="How is surface pressure generally measured, and at what actual height?" Tags="|measurements|atmospheric-radiation|barometric-pressure|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14174" PostTypeId="2" ParentId="14168" CreationDate="2018-05-16T17:17:03.497" Score="19" Body="&lt;p&gt;Since you termed it based on sea level, the gold mines in South Africa are not the deepest, they begin at an elevation of ~1500 m, meaning their 4 km depth is only 2.5 km below sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Kidd mine in Canada is 2.9 km deep and is located at an elevation of only ~250 m above sea level making it's depth 2.65 km below sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_deepest_mines&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/List_of_deepest_mines&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also if you don't care about the underground part and only care about below sea level, the undersea exploration of &lt;A HREF=&quot;https://en.wikipedia.org/wiki/Challenger_Deep&quot; rel=&quot;nofollow noreferrer&quot;&gt;Challenger Deep&lt;/a&gt; wins by a lot, they went ~12 km below sea level.&lt;/p&gt;&#xA;" OwnerUserId="12945" LastEditorUserId="6298" LastEditDate="2018-05-18T02:30:03.627" LastActivityDate="2018-05-18T02:30:03.627" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14175" PostTypeId="1" AcceptedAnswerId="14190" CreationDate="2018-05-16T18:08:55.957" Score="1" ViewCount="69" Body="&lt;p&gt;How to decide whether Brinell Hardness test, Rockwell test or Vicker's test is to be applied as far as grain-size is concerned? Is there any rule of thumb to decide the type of indentation hardness test?&lt;/p&gt;&#xA;" OwnerUserId="12916" LastEditorUserId="28050" LastEditDate="2018-05-18T00:11:55.507" LastActivityDate="2018-05-18T02:25:10.967" Title="Is there any rule of thumb to decide the indentation hardness test?" Tags="|geology|geophysics|mineralogy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14176" PostTypeId="2" ParentId="14172" CreationDate="2018-05-16T18:45:54.870" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;The instrument for measuring atmospheric pressure is the barometer.&#xA;Meteorologists apply standards defined by the World Meteorological&#xA;Organization to compare pressure measurements among themselves. They&#xA;are thus brought back to sea level and the barometers are calibrated&#xA;to indicate the pressure at sea level. This correction amounts to&#xA;adding the weight of the missing air column between the altitude of&#xA;the measuring point and the sea level (or a rare case, to subtract it&#xA;for a measurement point located under the surface of the sea).&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;source: &lt;a href=&quot;http://www.meteofrance.fr/prevoir-le-temps/observer-le-temps/parametres-observes/pression&quot; rel=&quot;nofollow noreferrer&quot;&gt;meteofrance&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user12525" LastEditorUserId="-1" LastEditorDisplayName="user12525" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-05-16T18:51:00.607" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14177" PostTypeId="2" ParentId="4646" CreationDate="2018-05-16T19:49:18.420" Score="1" Body="&lt;p&gt;Common Ca carbonates on Earth's crust have different concentrations of Mg. There is High Magnesium Calcite and Low Magnesium Calcite.&#xA;Aragonite has in comparison to calcite high levels of Mg. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you mixed trusted dolomite with an acid and you took aragonite, a carbonate similar to dolomite but with lower levels of Mg, I suposse aragonite is an intermediate carbonate product in the reaction instead of the complet decomposition of the dolomite. Dolomite is decomposed with HCl at high temperatures and not as quick as calcite. So the high concentration of Mg of the dolomite should alter the thermodynamical equilibrium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sequence of the reaction is:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Destruction of dolomite crystals. &lt;/li&gt;&#xA;&lt;li&gt;Formation of aragonite. --&gt; excess of Mg.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The Mg liberated from dolomite structure follows two ways. Aragonite accepts a low concentration of it. Then surplus Mg could be considered chemical waste while acetic acid is a chemical reactant.&#xA;In the case you get calcium acetate, acetic acid accepts Ca and it is transformed, but in this case is just a chemical reactant and his structure is not modified. Note the main difference is there is not excess of Ca.&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2018-05-21T11:15:27.127" LastActivityDate="2018-05-21T11:15:27.127" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14179" PostTypeId="2" ParentId="14172" CreationDate="2018-05-17T04:36:56.707" Score="2" Body="&lt;p&gt;When you look on meteorological maps the &quot;surface pressure&quot; is actually the reduced MSLP (mean sea-level pressure) value.  &lt;a href=&quot;https://www.weather.gov/bou/pressure_definitions&quot; rel=&quot;nofollow noreferrer&quot;&gt;See this NWS page for more info&lt;/a&gt;.  So whatever height the sensor is at above the ground, they regardless compare that height back versus the sea-level to report the pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I always figured barometers were sited along with the main instrument set.  Those indeed will all generally be raised up off the ground certain heights (aside from any soil temperature thermometers) to prevent issues with any standing water or snow cover.  See for example the &lt;a href=&quot;https://www.mesonet.org/index.php/site/about/instruments&quot; rel=&quot;nofollow noreferrer&quot;&gt;instrument list&lt;/a&gt; and &lt;a href=&quot;https://www.mesonet.org/common/meta/mesonet/photos/2013/&quot; rel=&quot;nofollow noreferrer&quot;&gt;extensive pictures&lt;/a&gt; for Oklahoma Mesonet site locations (slightly different setup, but the 2 meter temperature and 10 meter wind are widespread standards).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I was surprised to read in the &lt;a href=&quot;https://www.weather.gov/media/asos/aum-toc.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;ASOS User's Guide&lt;/a&gt; that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;At virtually all locations, the pressure sensors are located indoors&#xA;  within the ACU.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The ACU, which is the central processing unit for the ASOS, is usually&#xA;  located inside a climate controlled structure, such as an observing&#xA;  office or control tower building. It ingests data from the DCP(s) and&#xA;  pressure sensors, and is capable of accepting information from the FAA&#xA;  New Generation Runway Visual Range (NGRVR) system.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So it sounds like the barometer is often not on site, and there are indeed no specifications for height.  But since it's reduced to sea level regardless, the elevation is all that really matters to &lt;a href=&quot;https://www.mide.com/pages/air-pressure-at-altitude-calculator&quot; rel=&quot;nofollow noreferrer&quot;&gt;reduce it to MSLP&lt;/a&gt;, and so some variation in height of the sensor shouldn't matter.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-05-18T01:09:27.147" LastActivityDate="2018-05-18T01:09:27.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14180" PostTypeId="1" AcceptedAnswerId="14204" CreationDate="2018-05-17T06:32:49.373" Score="0" ViewCount="164" Body="&lt;p&gt;I am currently working on a project that involves the input of &lt;strong&gt;seismic attributes (instantaneous amplitude, instantaneous frequency etc.)&lt;/strong&gt; to a machine learning/deep learning model (eg. A Neural Network) . The output given by the model are &lt;strong&gt;petrophysical&lt;/strong&gt; properties such as &lt;strong&gt;Porosity,Permeability&lt;/strong&gt; etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To create this model, I need &lt;strong&gt;seismic&lt;/strong&gt; as well as &lt;strong&gt;digital well log data&lt;/strong&gt; from the same area which I have not been able to find.&lt;/p&gt;&#xA;" OwnerUserId="12718" LastActivityDate="2018-05-19T23:07:18.080" Title="Need seismic data and digital well log data from the same area?" Tags="|geology|geophysics|seismology|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14181" PostTypeId="2" ParentId="14168" CreationDate="2018-05-17T06:41:18.237" Score="-2" Body="&lt;p&gt;The book &quot;Blind Descent&quot; by James M. Tabor details this answer and I found it a terrific read.&#xA;I can't recall the exact depth, but what stuck in my mind was one particular explanation where the author said that we (humans) have gone as far below sea-level as above it. That is, roughly equivalent to the height of Everest - well over 8km.&lt;/p&gt;&#xA;" OwnerUserId="12954" LastActivityDate="2018-05-17T06:41:18.237" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14182" PostTypeId="1" CreationDate="2018-05-17T08:40:58.867" Score="1" ViewCount="81" Body="&lt;p&gt;I came across to a seismic volume labeled as &lt;em&gt;reghosted&lt;/em&gt;. In my understanding, a seismic survey is deghosted as part of a processing step. Then I wonder why one would like to reghosted the data? Is there any benefit in reghosted? Is it maybe reghosted something different than bring the ghost back to the data? Is there a visual inspection to know a data set is deghosted?&lt;/p&gt;&#xA;" OwnerUserId="12901" LastEditorUserId="28050" LastEditDate="2018-05-18T00:09:46.933" LastActivityDate="2018-05-19T23:12:14.770" Title="What does 'reghosted' mean in a seismic cube label?" Tags="|seismology|seismic|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14184" PostTypeId="1" CreationDate="2018-05-17T10:08:26.430" Score="3" ViewCount="73" Body="&lt;p&gt;Is there any possibility  to have tower cumulus (or cumulonimbus in worst case) without lightnings? And if this is happen what is the factor that cause this phenomenon?&lt;/p&gt;&#xA;" OwnerUserId="12712" LastActivityDate="2018-05-17T10:08:26.430" Title="Tower cumulus clouds without lightnings" Tags="|meteorology|clouds|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14185" PostTypeId="1" AcceptedAnswerId="14186" CreationDate="2018-05-17T16:02:55.830" Score="1" ViewCount="58" Body="&lt;p&gt;I came across this satellite animation the other day. It shows a reef being entirely destroyed to build an industrial complex (airport, harbor, various facilities...). The animated GIF is showcased on the website of a company called &lt;a href=&quot;https://www.digitalglobe.com/products/securewatch#feature-section&quot; rel=&quot;nofollow noreferrer&quot;&gt;Digital Globe&lt;/a&gt; (here is the &lt;a href=&quot;https://web.archive.org/web/20171223095313/https://www.digitalglobe.com/products/securewatch&quot; rel=&quot;nofollow noreferrer&quot;&gt;web page cached by the Internet Archive in case they take it down&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UGbpW.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UGbpW.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I find this quite shocking given how long it takes for reefs to form (I read &lt;a href=&quot;https://en.wikipedia.org/wiki/Coral_reef_protection&quot; rel=&quot;nofollow noreferrer&quot;&gt;&amp;quot;100,000 and 30 million years for a fully mature reef to form&amp;quot;&lt;/a&gt;). My understanding is that lots of those reefs are actually protected.&lt;/p&gt;&#xA;&lt;p&gt;My question (I know it's a tough one):&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Is there a way to find out which reef this was and whether or not it was protected?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="12964" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-05-17T16:54:27.930" Title="Was this reef protected?" Tags="|ocean|environmental-protection|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14186" PostTypeId="2" ParentId="14185" CreationDate="2018-05-17T16:54:27.930" Score="3" Body="&lt;p&gt;The caption under the image on the Digital Globe website identifies the location as Fiery Cross Reef.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Multiple sites identify what's going on as the Chinese government building an airstrip and related facilities on the site to solidify its claim to the South China Sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.bbc.com/news/world-asia-32331964&quot; rel=&quot;nofollow noreferrer&quot;&gt;According to this 2015 BBC story&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;China claims almost the whole of the South China Sea, resulting in&#xA;  overlapping claims with several other Asian nations including Vietnam&#xA;  and the Philippines.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That story is based on a &lt;a href=&quot;http://www.janes.com/article/50714/china-s-first-runway-in-spratlys-under-construction&quot; rel=&quot;nofollow noreferrer&quot;&gt;Jane's 360 analysis of satellite images&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The 23 March images show a paved section of runway 503 m by 53 m on&#xA;  the northeastern side of Fiery Cross Reef, which China began to turn&#xA;  into an island in late 2014. Paving and ground preparation of other&#xA;  sections of the runway has also begun further along the island. In&#xA;  addition, workers have paved about 400 m by 20 m of apron.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://pca-cpa.org/wp-content/uploads/sites/175/2016/07/PH-CN-20160712-Press-Release-No-11-English.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Permanent Court of Arbitration on the wider South China Sea territorial dispute between China and the Philippines: (PDF)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...China had caused severe harm to the coral reef environment and&#xA;  violated its obligation to preserve and protect fragile ecosystems and&#xA;  the habitat of depleted, threatened, or endangered species.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But it didn't seem that the reef in question was explicitly protected by any governmental action, especially given the dispute over which country governed the territory. China does not recognize the jurisdiction of the court.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2018-05-17T16:54:27.930" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14187" PostTypeId="1" CreationDate="2018-05-17T17:34:58.253" Score="4" ViewCount="4054" Body="&lt;p&gt;I have two questions based on the history of atmospheric oxygen levels depicted below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bbM09.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bbM09.png&quot; alt=&quot;graph of oxygen concentration in the Earth&amp;#39;s atmosphere over time, from wikipedia commons&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Sauerstoffgehalt-1000mj2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://commons.wikimedia.org/wiki/File:Sauerstoffgehalt-1000mj2.png&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The notes below the chart explain most of the changes in the past Gya.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;What they don't explain, however, is why oxygen has declined for&#xA;the last ~100 Mya. For example, is this explicable in terms of volcanism?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;They do explain the Permian decline in terms of volcanic activity,&#xA;but why do volcanoes affect oxygen levels?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="7803" LastEditorUserId="7803" LastEditDate="2018-05-18T16:07:38.167" LastActivityDate="2020-09-13T13:21:10.477" Title="Causes of fluctuations in atmospheric oxygen in past 300 Mya" Tags="|atmosphere|volcanology|earth-history|oxygen|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="14189" PostTypeId="2" ParentId="14180" CreationDate="2018-05-17T21:42:49.537" Score="2" Body="&lt;p&gt;The SEG has a list of open file seismic data sets here: &lt;a href=&quot;https://wiki.seg.org/wiki/Open_data&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://wiki.seg.org/wiki/Open_data&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a number of these surveys well logs are also given. &lt;/p&gt;&#xA;" OwnerUserId="777" LastActivityDate="2018-05-17T21:42:49.537" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14190" PostTypeId="2" ParentId="14175" CreationDate="2018-05-18T02:25:10.967" Score="0" Body="&lt;p&gt;No. Grain size is not a factor . Test method depends on the size and shape of the test piece and why the test is being done. Vickers can use different loads so can be used for very small areas and the microscope can be used to select certain locations such as a carburized layer. Rockwell can test larger specific locations such as the components of a weld HAZ. Brinell hits a fairly large area ,it also requires significant thickness like 1/2 &quot;. Vickers and Brinell results are based on the area of the impression , while Rockwell measures the depth of penetration. These comments apply to standard bench testers , portable testers is a different game.   &lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2018-05-18T02:25:10.967" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14191" PostTypeId="2" ParentId="14168" CreationDate="2018-05-18T03:56:31.740" Score="15" Body="&lt;p&gt;You generated multiple questions, I am going to list some of them. People can disagree with any of my answers, I made the estimations quickly.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;1.Record depth in the rocks from the surface a person has reached.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Based on your original question, &lt;a href=&quot;https://earthscience.stackexchange.com/a/14169/6298&quot;&gt;jamesqf's answer&lt;/a&gt; of the mine in South Africa may be the deepest.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;2.Record depth in the rocks from the surface a person has reached -see level is the reference-.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Based upon &amp;quot;under sea level&amp;quot;, &lt;a href=&quot;https://earthscience.stackexchange.com/a/14174/6298&quot;&gt;Josh King's answer&lt;/a&gt; of the Canadian mine should probably be the correct one.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;3.Record absolute inches under sea level a person has reached, including underwater immersion.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.deepseachallenge.com/the-expedition/mariana-trench/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Challenger Deep&lt;/a&gt; won when this question was asked, as &lt;a href=&quot;https://earthscience.stackexchange.com/a/14174/6298&quot;&gt;Josh King noted&lt;/a&gt;, but now &lt;a href=&quot;https://edition.cnn.com/travel/article/victor-vescovo-deepest-dive-pacific/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Victor Vescovo has this record&lt;/a&gt;. Mariana Trench is the deepest point on Earth's seabed.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;4.Record closest a human has come to Earth's center.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Earth_radius&quot; rel=&quot;nofollow noreferrer&quot;&gt;The difference between equatorial and polar radius is 22 km&lt;/a&gt;, so you might search for the answer at the Poles. I would not recommend the traveler to chose Antarctica, as it has an average elevation around 2000 meters. And I would say he would fails again at North Pole against Victor Vescoso's Marianas dives -he goes &amp;quot;on foot&amp;quot;, he is not a submariner :)-. Perhaps a military submarine that is traveling around the Arctic Ocean may be the winner. You will need to make some calculations to determine if the Arctic Seabed is closer to Earth's Center than the Marianas Trench.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;5.Record depth from the surface a person has reached &amp;quot;on foot&amp;quot;.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;If you consider miners that take an elevator to still be going &amp;quot;on foot&amp;quot;, the South Africa ones should have that record. If not, a spelunker.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;6.Record absolute depth under sea level a person has reached &amp;quot;on foot&amp;quot;.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;If you consider Vescoso to have been &amp;quot;on foot&amp;quot;, he wins again. If not, and you consider miners going to their jobs as being &amp;quot;on foot&amp;quot;, then it would be the Canadian miners (2.65 km below see level). If you are strict against both, my first thougth is then maybe port workers (note a submariner won't win in this case neither), or maybe a spelunker, but user Semidiurnal Simon clarifies it on comments. I was wrong (I said I made the estimations quickly) as: &amp;quot;For the strictest &amp;quot;on foot&amp;quot;, it won't be port workers, it'll be somebody in a below-sea-level basin (e.g. by the Dead Sea), or possibly a low-altitude mine that has a drift (slanted corridor) entry and so doesn't require an elevator.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;7.Record absolute depth under surface by drilling.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Sending machines from the surface (by borehole) rather than humans, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kola Superdeep Borehole&lt;/a&gt; is the deepest (12km).&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;8.Record closest drill to Earth's Center.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;http://www-odp.tamu.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ocean Drilling Program&lt;/a&gt; could have this record, but I cannot determine where. Average seabed deep rounds -4.000 m. and the Arctic Ocean is not a deep ocean in comparison with the Pacific and Atlantic. So the Kola Borehole may well have this record too.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;Deepest drillings.&#xA;The Kola Superdeep Borehole on the Kola peninsula of&#xA;Russia reached 12,262 metres (40,230 ft) and is the deepest&#xA;penetration of the Earth's solid surface. The German Continental Deep&#xA;Drilling Program at 9.1 kilometres (5.7 mi) has shown the earth crust&#xA;to be mostly porous. Drillings as deep as 2.1 kilometres (1.3 mi) into&#xA;the seafloor were achieved at DSDP/ODP/IODP Hole 504B.[citation&#xA;needed] Because the continental crust is about 45 km thick on average,&#xA;whereas oceanic crust is 6-7 km thick, deep drillings have penetrated&#xA;only the upper 25-30% of both crusts.&lt;/p&gt;&#xA;&lt;p&gt;source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Scientific_drilling&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/w8V3s.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/w8V3s.png&quot; alt=&quot;Deeper drillings and dives&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3PlDm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3PlDm.png&quot; alt=&quot;Closest projects to Earth's Core&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;*Distorted scale. &lt;a href=&quot;http://www.chegg.com/homework-help/recent-advances-seismic-tomography-modified-ideas-earth-s-in-chapter-3-problem-13asq-solution-9780077415594-exc&quot; rel=&quot;nofollow noreferrer&quot;&gt;You can take a look at this image&lt;/a&gt; to have an idea how thick the crust is at Earth scale.&lt;/p&gt;&#xA;&lt;p&gt;Sources of the images: &lt;a href=&quot;https://thenounproject.com/term/submarine/445592/&quot; rel=&quot;nofollow noreferrer&quot;&gt;submarine&lt;/a&gt;, &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:River_bus_icon.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;boat&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://edition.cnn.com/2017/04/07/asia/japan-drill-mantle/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; is some information about a Japanese plan to reach the mantle.&lt;/p&gt;&#xA;&lt;p&gt;There was a proposal by geophysician David J. Stevenson that was supposed to go to the Earth's Core, but it was controversial. &lt;a href=&quot;https://www.nature.com/articles/423239a&quot; rel=&quot;nofollow noreferrer&quot;&gt;It was published on Nature on 2003.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;I encourage students to try to solve the question raised in option 4 to determine:&lt;br /&gt;&#xA;&lt;em&gt;&lt;strong&gt;Which is closer to Earth's Center, the Marianas Trench or the North Pole's seabed?&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Related posts:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/246/can-we-really-travel-through-earths-core/454&quot;&gt;Can we really travel through earth's core?&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/2772/farthest-point-from-the-center-of-the-earth&quot;&gt;Farthest point from the center of the Earth&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user12525" LastEditorUserId="-1" LastEditorDisplayName="user12525" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-06-02T11:58:55.217" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="14192" PostTypeId="2" ParentId="14180" CreationDate="2018-05-18T12:27:54.137" Score="2" Body="&lt;p&gt;There is a data repository &lt;a href=&quot;https://opendtect.org/osr/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://opendtect.org/osr/&lt;/a&gt; . from what I understand, it is a repository made for OpendTect and maintain by dGB Earth Sciences. There you can find seismic and well data.&#xA;Also New Zeland gov has published this &lt;a href=&quot;https://www.linkedin.com/feed/update/urn:li:activity:6384901298944380928&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.linkedin.com/feed/update/urn:li:activity:6384901298944380928&lt;/a&gt;. That one, I didn't have the chance to work with, but should work fine for seens you need. Austarlia has a similar open data base but can't find the link now.&lt;/p&gt;&#xA;" OwnerUserId="12901" LastActivityDate="2018-05-18T12:27:54.137" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14193" PostTypeId="2" ParentId="52" CreationDate="2018-05-18T13:32:01.977" Score="2" Body="&lt;p&gt;It is possible to compute the relevant moist air entropy by using the Third law values. This has been done first by Hauf and Höller (1987). A moist-air potential temperature has been defined by Marquet (2011, ..., 2017). This  moist-air potential temperature is truly synonymous with the moist-air entropy and is different from the previous values published by Emanuel or Pauluis, because the Third law values generate a new term which has large physical impacts.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Hauf, T., and H. Höller, 1987: Entropy and potential temperature.&#xA;J. Atmos. Sci., 44 (20), 2887–2901&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Marquet, P., 2011: Definition of a moist entropy potential temperature:&#xA;application to FIRE-I data flights. Quart. J. Roy. Meteorol.&#xA;Soc., 137 (9), 768–791&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Marquet, P., 2017: A third-law isentropic analysis of a simulated&#xA;hurricane. J. Atmos. Sci., 74 (10), 3451–3471&lt;/p&gt;&#xA;" OwnerUserId="12972" LastActivityDate="2018-05-18T13:32:01.977" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14194" PostTypeId="2" ParentId="14187" CreationDate="2018-05-18T13:33:52.997" Score="4" Body="&lt;p&gt;Here's a somewhat different looking graph, from &lt;a href=&quot;http://science.sciencemag.org/content/316/5824/557.summary&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oxygen and Evolution,&#xA;Robert A. Berner et al., &lt;em&gt;Science&lt;/em&gt; 316, 557 (2007)&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0maN1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0maN1.png&quot; alt=&quot;Graph depicting estimates of the percentage of oxygen in the atmosphere over the last 550 million years.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The graph shows three marked drops in O&lt;sub&gt;2&lt;/sub&gt; levels, each corresponding to an extinction event. These are intervals 4, 9, and 11. Interval 9, the largest such drop, represents the end Permian event about 252 million years ago. Interval 11 corresponds to the end Triassic event, 201 million years ago. The unsourced wikipedia graph linked in the question has at most a superficial resemblance to this sourced graph.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now for your two questions.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What they don't explain, however, is why oxygen has declined for the last ~100 Mya. For example, is this explicable in terms of volcanism?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I would take even the sourced graph that I used with a grain of salt. That unsourced wikipedia graph: A very large block of salt is needed.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;They do explain the Permian decline in terms of volcanic activity, but why do volcanoes affect oxygen levels?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It is very widely conjectured that the end Permian extinction event was caused by the Siberian Traps. This extreme volcanism may have triggered coal fires, thereby reducing oxygen levels. This remains conjecture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What isn't conjecture is that the end Permian event killed off almost all life extant at that time, including much of the algae and plants that produce oxygen. Without a continuous supply of new oxygen, oxygen sinks such as unweathered rock will inevitably result in a decline in oxygen levels.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-05-18T13:33:52.997" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14195" PostTypeId="1" AcceptedAnswerId="14196" CreationDate="2018-05-18T19:33:18.810" Score="0" ViewCount="157" Body="&lt;p&gt;I am asking this question, because I don't know the importance of oxidation process at all, and this question pops into my mind because currently I've been researching why apples turn into brown color when is it exposed to air/oxygen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And I find at that the cause of this is due to the Polyphenol Oxidase (PPO) enzymes being present inside the apple, when the enzyme is exposed to air/oxygen, it triggers a chemical reaction called Oxidation.&lt;/p&gt;&#xA;" OwnerUserId="12975" LastEditorUserId="12975" LastEditDate="2018-05-19T07:00:26.693" LastActivityDate="2018-05-19T07:00:26.693" Title="What is the importance of oxidation process?" Tags="|earth-system|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14196" PostTypeId="2" ParentId="14195" CreationDate="2018-05-18T19:43:46.077" Score="0" Body="&lt;p&gt;Perhaps this is better put on the Chemistry SE page since oxidation is much more important than beyond earth sciences, but I'll give my take on it from an atmospheric sciences perspective.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If oxidation isn't allowed to take place, then the hydroxyl radical ($\ce{^*OH}$), nicknamed the detergent of the atmosphere, cannot remove pollutants from the atmosphere. I think it is evident why removing pollution is a good thing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is just one of many uses that oxidation has.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2018-05-18T19:43:46.077" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14198" PostTypeId="1" AcceptedAnswerId="14199" CreationDate="2018-05-18T19:46:55.697" Score="5" ViewCount="2895" Body="&lt;p&gt;Many minerals have a streak that's surprisingly different from it's outward color. Why is this? What causes the optical properties to change if the mineral is powdered?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;" OwnerUserId="12977" LastActivityDate="2018-05-18T20:09:09.027" Title="Why is streak different from color?" Tags="|minerals|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14199" PostTypeId="2" ParentId="14198" CreationDate="2018-05-18T20:09:09.027" Score="8" Body="&lt;p&gt;It mostly has to do with the fact many minerals are partially translucent. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Trace impurities or even crystal structure can dominate the color of a translucent material but when ground in to a fine powder (streak) they can no longe do so and you can see the true color. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other minerals surface oxidation can mask the true color.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2018-05-18T20:09:09.027" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14200" PostTypeId="1" CreationDate="2018-05-18T21:13:56.217" Score="10" ViewCount="3120" Body="&lt;p&gt;There has been a lot of noise in the news in the last few days because Congressman Mo Brooks from Alabama claimed that erosion played a role in rising sea levels. Quoting from &lt;a href=&quot;http://www.sciencemag.org/news/2018/05/republican-lawmaker-rocks-tumbling-ocean-causing-sea-level-rise&quot; rel=&quot;noreferrer&quot;&gt;Science magazine&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Brooks then said that erosion plays a significant role in sea-level rise, which is not an idea embraced by mainstream climate researchers. He said the California coastline and the White Cliffs of Dover tumble into the sea every year, and that contributes to sea-level rise. He also said that silt washing into the ocean from the world's major rivers, including the Mississippi, the Amazon and the Nile, is contributing to sea-level rise.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Every time you have that soil or rock or whatever it is that is deposited into the seas, that forces the sea levels to rise, because now you have less space in those oceans, because the bottom is moving up,&amp;quot; Brooks said.&lt;/p&gt;&#xA;&lt;p&gt;Duffy responded: &amp;quot;I'm pretty sure that on human time scales, those are minuscule effects.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Everywhere I have read, people just say &amp;quot;that man is an idiot&amp;quot;; but nowhere have I seen an authoritative, fact-based response to prove this.&lt;/p&gt;&#xA;&lt;p&gt;How much does the sediment carried into the oceans by rivers contribute to the rise in sea level?&lt;/p&gt;&#xA;" OwnerUserId="453" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-08-03T14:39:18.083" Title="How much does sea level rise due to sediment deposition?" Tags="|oceanography|sedimentology|sea-level|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14201" PostTypeId="2" ParentId="14200" CreationDate="2018-05-18T21:13:56.217" Score="18" Body="&lt;p&gt;In a 1983 &lt;em&gt;Journal of Geology&lt;/em&gt; paper by Milliman and Meade, &quot;World-Wide Delivery of River Sediment to the Oceans&quot; (&lt;a href=&quot;https://www.journals.uchicago.edu/doi/abs/10.1086/628741&quot; rel=&quot;noreferrer&quot;&gt;link&lt;/a&gt;) it is estimated that the world's rivers carry about $13.5\times 10^9$ tonnes of sediment per year. If we assume an average density of $2.5~\rm{g/cm^3}$, this corresponds to a volume of 8.8 cubic kilometers. The total surface area of the world's oceans is 360 million square kilometers. This means that the sediment of the rivers contributes to a rise in sea level of 15 µm per year, or 1.5 mm per century.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The IPCC &lt;a href=&quot;https://en.wikipedia.org/wiki/IPCC_Fifth_Assessment_Report&quot; rel=&quot;noreferrer&quot;&gt;estimated in its fifth report&lt;/a&gt; that the average rate of sea level rise is about 3.2 mm per year. That means that about 0.5 % of that rise could be attributed to sediment. It is certainly not a major factor, but is non-zero all the same.&lt;/p&gt;&#xA;" OwnerUserId="453" LastActivityDate="2018-05-18T21:13:56.217" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14202" PostTypeId="1" AcceptedAnswerId="14391" CreationDate="2018-05-19T07:31:56.397" Score="0" ViewCount="514" Body="&lt;p&gt;I'm trying to see if I understand the concepts of saturation, vapor pressure and cloud formation correctly. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When, at a given temperature and height in the atmosphere, the rate of evaporation and condensation are equal, then the air is said to be saturated and clouds form (assuming the presence of nuclei).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the rate of evaporation is &lt;em&gt;greater&lt;/em&gt; than the rate of condensation, a state of undersaturation is reached and no clouds form. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the rate of evaporation is &lt;em&gt;less&lt;/em&gt; than the rate of condensation, a state of supersaturation is reached and clouds form. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is my understanding of this correct? &lt;/p&gt;&#xA;" OwnerUserId="11043" LastActivityDate="2018-06-10T06:53:28.793" Title="Is my understanding of saturation and cloud formation correct?" Tags="|clouds|evaporation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14203" PostTypeId="2" ParentId="14182" CreationDate="2018-05-19T14:01:34.003" Score="2" Body="&lt;p&gt;As you rightly say, data will normally be deghosted during processing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, sometimes the deghosting is performed by the acquisition company rather than the processing contractor. The most obvious example would be PGS Geostreamer data, where 'raw' field tapes supplied by PGS to the customer are the upcoming wavefield, with the receiver ghost already removed. This is because the process of combining the velocity sensor and hydrophone data to remove the sea surface reflection is PGS's secret sauce - in many ways building a multi-sensor streamer is the easy part. They work with the true raw data internally, but never supply it to anyone else.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is normally fine, but if the data is later processed (or reprocessed) by someone else, then complications can arise. If this other processing company wants to perform Full Waveform Inversion, which involves modelling a synthetic wavefield and comparing to the recorded wavefield, then the absence of the receiver ghost will cause an issue. Since the boundary condition at the sea surface has to be reflective to model the multiples correctly. Thus, they may add the receiver ghost back into the data by making an assumption of the sea surface reflectivity and adding it back, creating a 'reghosted' dataset to compare to the synthetics within the FWI.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, this would be an internal working dataset for the processing company, not something that would be supplied to the client. So I am surprised you would come across it without knowing what it was, if you see what I mean.&lt;/p&gt;&#xA;" OwnerUserId="12979" LastEditorUserId="12979" LastEditDate="2018-05-19T23:12:14.770" LastActivityDate="2018-05-19T23:12:14.770" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14204" PostTypeId="2" ParentId="14180" CreationDate="2018-05-19T23:07:18.080" Score="2" Body="&lt;p&gt;Conoco Philips made the Poseidon data available including 3D seismic data and well logs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://drive.google.com/drive/folders/0B7brcf-eGK8CRUhfRW9rSG91bW8&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://drive.google.com/drive/folders/0B7brcf-eGK8CRUhfRW9rSG91bW8&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All data is made available under the terms of the Creative Commons “Attribution 3.0 Australia” licence, be sure to treat it accordingly.&lt;/p&gt;&#xA;" OwnerUserId="507" LastActivityDate="2018-05-19T23:07:18.080" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14205" PostTypeId="1" AcceptedAnswerId="14208" CreationDate="2018-05-19T23:41:01.483" Score="2" ViewCount="3577" Body="&lt;p&gt;Looking at this website, I can see the melting point of the following minerals: &lt;a href=&quot;http://hyperphysics.phy-astr.gsu.edu/hbase/Geophys/meltrock.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://hyperphysics.phy-astr.gsu.edu/hbase/Geophys/meltrock.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apparently at a temperature of 1200 °C, all the minerals exist in a molten state. But, looking at the melting point for &lt;a href=&quot;https://en.wikipedia.org/wiki/Quartz&quot; rel=&quot;nofollow noreferrer&quot;&gt;quartz&lt;/a&gt; on Wikipedia I find that the melting point is close to 1700 °C. What’s going on here?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It can’t be an effect of the pressure. In the interior, the pressure will be higher and thus further increase the melting point. &lt;/p&gt;&#xA;" OwnerUserId="12977" LastEditorUserId="725" LastEditDate="2018-05-20T11:53:28.390" LastActivityDate="2018-05-20T14:45:21.270" Title="Melting point of minerals" Tags="|geochemistry|mineralogy|minerals|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14206" PostTypeId="1" CreationDate="2018-05-20T06:36:38.037" Score="1" ViewCount="454" Body="&lt;p&gt;Visit any geothermal area like Iceland, Yellowstone or Rotorua, and you notice a disgusting smell. The web-pages all discuss hydrogen sulphide, but there is something else, like burned bacon. I'm guessing some kind of sulphurous organic?&lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2018-05-20T06:36:38.037" Title="What's that geothermal smell?" Tags="|geothermal-heat|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14208" PostTypeId="2" ParentId="14205" CreationDate="2018-05-20T11:36:45.570" Score="6" Body="&lt;p&gt;Start with my answer to this very highly related question here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/2742/725&quot;&gt;https://earthscience.stackexchange.com/a/2742/725&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The melting point of minerals in isolation, or a pure substance is higher than mixtures of minerals. For example - a (well-mixed) mixture of quartz and pyroxene will melt at a lower temperature than pure quartz or pure pyroxene. The exact temperature is dependent on the proportions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, the more different kind of components (i.e. &quot;things&quot;: minerals, elements, molecules, etc) you add to a mixture, the lower the melting point of the mixture as a whole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, sea water melts at -2 °C because it's a mixture of water (melts at 0 °C) and all kinds of salts. Steel melts at a lower temperature than pure iron because it's a mixture of iron and carbon.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-05-20T11:36:45.570" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14210" PostTypeId="2" ParentId="14205" CreationDate="2018-05-20T14:45:21.270" Score="1" Body="&lt;p&gt;The eutectic is the minimum melting point of a mixed material, like soda lime glass made from sodium hydroxide, calcium oxide, and silicon dioxide. That mixture, in the proper proportions, lowers the melting point of quartz sand (silicon dioxide) from 1700 to under 1000 Celsius. In the mantle the mixture is far more complex but if I remember my geochemistry Aluminium, Iron, Magnesium, and Calcium are the main elements that lower the melting point of pure silica in magmatic melts. Water can be very important as it not only lowers the melting point of saturated rocks but also carries heat into lower temperature melting materials, especially in subduction zones.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-05-20T14:45:21.270" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14212" PostTypeId="1" CreationDate="2018-05-20T19:16:08.263" Score="18" ViewCount="44882" Body="&lt;p&gt;From me looking at maps, excluding the Caspian sea and the Great Lakes, I see these in common for seas and lakes:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seas&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Most are saltwater&lt;/li&gt;&#xA;&lt;li&gt;Connected to the rest of the ocean via either an isthmus, strait, river, or&#xA;gulf&lt;/li&gt;&#xA;&lt;li&gt;Bigger and deeper than lakes&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Lakes&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Most are freshwater&lt;/li&gt;&#xA;&lt;li&gt;Landlocked&lt;/li&gt;&#xA;&lt;li&gt;Not nearly as big or deep as any sea&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So back to these 2 bodies of water in question. Some people consider the Caspian sea to be a lake and others consider it to be a sea. While historically, it might have been part of a sea, it is landlocked now so it would be more suited to call this the Caspian Salt Lake, thus making it the largest lake on Earth and also the largest saline lake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Great Lakes are also in question, to me at least. While the majority of the world considers them lakes and they were historically a lake (really, the rivers and small lakes in that area connecting them are so small in comparison that it is basically 1 body of water), the Erie canal has since then connected the lakes to the St. Lawrence River. So it would be more suited to call this the Great Freshwater Sea. I have no idea how this would rank up to other seas like the Mediterranean Sea in area but it would be one of the world's few freshwater seas (Joining the Sea of Galilee).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So why are the Great Lakes not considered a freshwater sea when other than the freshwater, they are essentially like any other sea?&lt;/p&gt;&#xA;" OwnerUserId="1388" LastEditorUserId="-1" LastEditDate="2019-06-05T19:34:04.937" LastActivityDate="2022-01-26T13:25:16.487" Title="Why are the Great Lakes not considered a sea?" Tags="|oceanography|lakes|" AnswerCount="3" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="14213" PostTypeId="2" ParentId="14212" CreationDate="2018-05-20T20:53:01.877" Score="39" Body="&lt;p&gt;&quot;Sea&quot; versus &quot;lake&quot; versus &quot;just part of the ocean&quot; is a bit fuzzy, but there are two things that are universal about seas:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;They are saline.&lt;/li&gt;&#xA;&lt;li&gt;They are either &lt;a href=&quot;https://en.wikipedia.org/wiki/Endorheic_basin&quot; rel=&quot;noreferrer&quot;&gt;endorheic&lt;/a&gt; or have a sea-level (tidally-influenced) connection to the ocean.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Now, let's see how the Great Lakes look under these criteria.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Saline?  No, salinity is &lt;a href=&quot;https://ponce.sdsu.edu/lakesalinityworld.html&quot; rel=&quot;noreferrer&quot;&gt;0, give or take measurement error&lt;/a&gt;.  Even the Baltic Sea, the least-salty of the generally-recognized seas, is far more saline, at 0.5%.&lt;/li&gt;&#xA;&lt;li&gt;Endorheic?  No, they're connected to the ocean by way of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Saint_Lawrence_River&quot; rel=&quot;noreferrer&quot;&gt;Saint Lawrence River&lt;/a&gt;, and have been for at least 10,000 years.&lt;/li&gt;&#xA;&lt;li&gt;Sea-level connection?  No, the Saint Lawrence River has &lt;a href=&quot;https://en.wikipedia.org/wiki/Saint_Lawrence_River#Geography&quot; rel=&quot;noreferrer&quot;&gt;about 500 km of non-tidal flow below the outlet of Lake Ontario&lt;/a&gt;, over which it descends 75 meters.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Score: 0 out of 3.  Not surprising that the Great Lakes are considered lakes, not seas.&lt;/p&gt;&#xA;" OwnerUserId="2643" LastEditorUserId="12998" LastEditDate="2018-05-21T09:39:50.403" LastActivityDate="2018-05-21T09:39:50.403" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14214" PostTypeId="1" AcceptedAnswerId="14215" CreationDate="2018-05-20T22:24:26.393" Score="27" ViewCount="10355" Body="&lt;p&gt;There's a song &quot;Blizzard's Never Seen the Desert's Sand&quot;. Given Antarctica is a desert, someone questioned the title's validity. BUT is there sand in Antarctica?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd imagine yes as it's a pretty basic soil and Antarctica is a big place, and I know there is land mass, not just ice, in Antarctica. I'm not sure though - any more info or evidence about the presence of sand?&lt;/p&gt;&#xA;" OwnerUserId="4789" LastEditorUserId="2470" LastEditorDisplayName="user12525" LastEditDate="2021-07-06T07:01:06.943" LastActivityDate="2022-03-04T22:29:42.263" Title="Is there sand in Antarctica?" Tags="|geology|sedimentology|soil|geomorphology|antarctica|" AnswerCount="3" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="14215" PostTypeId="2" ParentId="14214" CreationDate="2018-05-20T22:45:51.480" Score="49" Body="&lt;p&gt;Yes. In fact, there are &lt;a href=&quot;https://youtu.be/v6P_urSCGSA?t=1m14s&quot; rel=&quot;noreferrer&quot;&gt;sand-dunes in Antarctica [1:15]&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mtvzJ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mtvzJ.jpg&quot; alt=&quot;Paleoclimwtes: What are Sand-dunes doing in Antarctica?&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12990" LastEditorUserId="3109" LastEditDate="2018-05-21T13:32:43.380" LastActivityDate="2018-05-21T13:32:43.380" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14216" PostTypeId="1" CreationDate="2018-05-21T05:25:43.880" Score="5" ViewCount="99" Body="&lt;p&gt;What industries or government departments hire volcanologists and igneous petrologists/geochemists in the United States? &lt;/p&gt;&#xA;" OwnerUserId="11043" LastEditorUserId="11043" LastEditDate="2018-05-21T06:09:44.487" LastActivityDate="2020-10-13T15:57:25.010" Title="Employment of Volcanologists and Petrologists" Tags="|geochemistry|volcanology|petrology|" AnswerCount="1" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14217" PostTypeId="2" ParentId="14212" CreationDate="2018-05-21T08:21:30.627" Score="8" Body="&lt;p&gt;From a geological point of view, the two are very different.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Caspian Sea is thought to be the remnant of an ocean that got cut off from the ocean system (similar to how the Mediterranean might have been periodically cut off and re-connected to the oceans) due to tectonic uplift and a drop in sea levels. The Black Sea was part of the same ocean, but has a much lower inflow than it loses to evaporation - hence the Black Sea has a salinity much higher than the oceans, while the Caspian Sea has a salinity significantly lower than the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Great Lakes could be considered a &lt;em&gt;failed&lt;/em&gt; ocean. They are in a place where rifting started to create a new ocean, but it never got connected to the ocean system (and flooded), and that was still the case when the rifting eventually stopped. Those rifts were then further (much later) &quot;excavated&quot; by glaciers. The large depressions got filled with melt water (at the end of the last ice age) and rainwater over time, as is typical of many other large/deep lakes. Unsurprisingly, the glacier-sourced melt water wasn't very salty.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the future, the Caspian Sea will probably get slightly saltier, and filled with sediment. While the influx of fresh water has driven the salinity relatively low compared to the oceans, the sea now only loses water through evaporation - so there's no way for the (tiny amounts) of incoming salts and (relatively large amounts) of sediment to go. As the depth decreases, there might be some expansion of the surface area, but that's mostly temporary - it increases the evaporation rate without increasing the inflow, so water is lost over time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In contrast, the Great Lakes have an outflow into the ocean, which carries away a lot of the dissolved salts and sediment. Right now, the outflow, combined with evaporation both natural and man made, is larger than the inflow. Overall, this means it's not going to get saltier over time - it keeps pretty much constant salinity, which is pretty much zero compared to the oceans. As erosion continues over the Saint Lawrence River, the outflow will probably increase, resulting in a drop in the water levels of the lakes. However, unlike e.g. the Black Sea, this will not increase the salinity, since the salts are lost through the outflow, rather than being concentrated by evaporation.&lt;/p&gt;&#xA;" OwnerUserId="217" LastActivityDate="2018-05-21T08:21:30.627" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="14219" PostTypeId="1" CreationDate="2018-05-21T14:08:52.013" Score="3" ViewCount="501" Body="&lt;p&gt;I have been doing some research into global warming, and I was curious as to whether or not increasing the temperature of the oceans would affect tsunamis to any significant degree.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My gut tells me that adding more energy into the water would make the tsunami worse, but tsunamis are caused by earthquakes, not by heating like a hurricane. On the other hand, increasing heat would reduce the density of the water, which might make them &lt;em&gt;less&lt;/em&gt; severe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would these forces actually affect the tsunami? Which one would win, or would they cancel out? Or am I completely missing something obvious?&lt;/p&gt;&#xA;" OwnerUserId="12999" LastActivityDate="2018-05-21T14:33:37.467" Title="Does global warming affect tsunamis?" Tags="|climate-change|water|natural-disasters|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14220" PostTypeId="1" AcceptedAnswerId="14222" CreationDate="2018-05-21T14:24:26.273" Score="2" ViewCount="198" Body="&lt;p&gt;Coming from this post: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/14187/causes-of-fluctuations-in-atmospheric-oxygen-in-past-300-mya&quot;&gt;Causes of fluctuations in atmospheric oxygen in past 300 Mya&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I believe there are a lot of questions still unanswered about Permian-Triassic mass extinction, but I ask only for its influence on the Carbon Cycle, atmosphere levels and climate in general.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What did the extinction change in Earth's system?&#xA;Did unicellular organisms restored some kind of new equilibrium?&#xA;What do we know?&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorUserId="10735" LastEditDate="2018-07-23T15:47:19.460" LastActivityDate="2018-07-23T15:47:19.460" Title="Permian-Triassic mass extinction. Consequences on Earth's system" Tags="|climate|mass-extinction|biomass|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14221" PostTypeId="2" ParentId="14219" CreationDate="2018-05-21T14:33:37.467" Score="5" Body="&lt;p&gt;Pretty confident to answer No here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tsunamis are caused by water displacement due to earthquakes; this has nothing to do with global warming.  Any changes in density would be trivial, and although the water would have more thermal energy, this would not affect or be influenced by the kinetic energy of the Tsunami.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only way in which a tsunami would be made more severe would be that any sea level rise due to global warming would be added to the Tsunami height. &lt;/p&gt;&#xA;" OwnerUserId="8217" LastActivityDate="2018-05-21T14:33:37.467" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14222" PostTypeId="2" ParentId="14220" CreationDate="2018-05-21T17:16:52.533" Score="1" Body="&lt;p&gt;Wow, I just finished watching &lt;a href=&quot;https://www.youtube.com/watch?v=rdGesZVBDO8&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; it seems we know, or can guess, quite a bit about the level of Carbon, particularly Methane that were released at the end of the Permian and what they did to the climate. What seems to be missing is any consensus about why the Permian extinction &lt;em&gt;stopped&lt;/em&gt; just that once things settled down climate and atmosphere swung back to about where they'd been beforehand. Inference to best-guess? It was rain and rocks that did most of it, with the biosphere in such a mess and so much new surface rock in Siberia the main mechanism to remove Carbon from the atmosphere would be chemical weathering; the rain dissolves Methane and Carbon Dioxide forming complex acidic solutions that react with the fresh rock, this forms insoluble Carbonates which lock carbon in the ground.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-05-21T17:16:52.533" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="14224" PostTypeId="1" CreationDate="2018-05-21T18:35:25.087" Score="4" ViewCount="80" Body="&lt;p&gt;There looks like a large undersea circular feature (&lt;a href=&quot;https://www.google.co.uk/maps/@37.3118628,-25.0687081,333063m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google maps&lt;/a&gt;) about 120km across with its north edge on Sao Miguel Island and its south edge on Santa Maria Island.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has any work been done to say whether or not it's a real feature, and if so what it is? When I tried to find out about caldera around the Azores I only found stuff about the smaller caldera on the islands.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cheers&lt;/p&gt;&#xA;" OwnerUserId="12736" LastActivityDate="2018-05-21T18:35:25.087" Title="Is there a large undersea caldera in the Azores?" Tags="|geology|volcanology|impacts|sea-floor|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14226" PostTypeId="2" ParentId="14214" CreationDate="2018-05-21T22:00:08.913" Score="14" Body="&lt;p&gt;&lt;a href=&quot;https://www.livescience.com/15631-antarctica-dunes-sign-climate-change.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;This LiveScience article&lt;/a&gt; suggests the areas aren't major:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The scant areas that are free of snow and ice make up less than 0.4&#xA;percent of the continental land mass. In places there, the wind has&#xA;built sand dunes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.the-cryosphere.net/10/1665/2016/tc-10-1665-2016.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article by Burton-Johnson et al., 2016&lt;/a&gt; on automated satellite analysis methods, summarized in &lt;a href=&quot;http://%5BMcMurdo%20Dry%20Valleys%5D%5B3%5D&quot; rel=&quot;nofollow noreferrer&quot;&gt;this DailyMail article&lt;/a&gt;, indicates refined estimates nearer 0.18% of the continent is not covered by ice/snow.&lt;/p&gt;&#xA;&lt;p&gt;Based upon the &lt;a href=&quot;https://en.wikipedia.org/wiki/Antarctica&quot; rel=&quot;nofollow noreferrer&quot;&gt;area of Antarctica&lt;/a&gt; from Wikipedia (&lt;a href=&quot;https://www.sporcle.com/games/mg10/continents-by-area&quot; rel=&quot;nofollow noreferrer&quot;&gt;you might be surprised how big Antarctica is!&lt;/a&gt;), that would equate to around 10,000 mi&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt; of uncovered land (see comments for comparison).  Of course it may well be that not even all of that area is sand.&lt;/p&gt;&#xA;&lt;p&gt;It looks from the articles like the largest place to find these sands are the &lt;a href=&quot;https://en.wikipedia.org/wiki/McMurdo_Dry_Valleys&quot; rel=&quot;nofollow noreferrer&quot;&gt;McMurdo Dry Valleys&lt;/a&gt;, such as &lt;a href=&quot;https://www.google.com/maps/@-77.383333,161.933333,6679m/data=!3m1!1e3?hl=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;Victoria Valley&lt;/a&gt;, which are on the &lt;a href=&quot;https://earthscience.stackexchange.com/a/13244/6298&quot;&gt;Eastern Antarctica sublandmass&lt;/a&gt; [see the sentences directly above the image entitled Deglaciated Antarctic Topography, plus that image itself].&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;So it sounds like they really do exist, but are relatively rare expanses!&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-03-01T21:35:42.437" LastActivityDate="2022-03-01T21:35:42.437" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14227" PostTypeId="1" CreationDate="2018-05-21T23:19:42.763" Score="6" ViewCount="2676" Body="&lt;p&gt;Like many people, while in school I learned there were four Oceans on Earth - Pacific, Atlantic, Indian, Arctic. In general I think it was described that the currents and the surrounding continents are what divided them into different oceans. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now there is a Southern (Antarctic Ocean). I thought (when I was taught) that that area was just Southern Pacific and Southern Atlantic, but I'm sort of fuzzy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How (or why) was it determined the Southern Ocean is an Ocean?&lt;/p&gt;&#xA;" OwnerUserId="13009" LastActivityDate="2018-05-22T08:14:10.530" Title="Why are there 5 oceans?" Tags="|ocean|" AnswerCount="1" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="14230" PostTypeId="2" ParentId="14227" CreationDate="2018-05-22T07:33:08.343" Score="5" Body="&lt;p&gt;The Southern Ocean does have its own current, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Antarctic_Circumpolar_Current&quot; rel=&quot;noreferrer&quot;&gt;Antarctic Circunmpolar Current&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It helps generate the &lt;a href=&quot;https://en.wikipedia.org/wiki/Circumpolar_deep_water&quot; rel=&quot;noreferrer&quot;&gt;Circumpolar Deep Water&lt;/a&gt; due to density gradients. Ice melts and thus salinity decreases. Differences in salinity are the reason for bulk water movements in the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus the Southern Ocean contributes to cool the Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geographical criteria may be open for discussion, but oceanographically speaking it is a separate system from its neighbors, the Atlantic, Pacific and Indian. &lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorUserId="6298" LastEditDate="2018-05-22T08:14:10.530" LastActivityDate="2018-05-22T08:14:10.530" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14231" PostTypeId="1" CreationDate="2018-05-22T09:13:03.740" Score="6" ViewCount="118" Body="&lt;p&gt;Once upon a time I seem to remember there being a plethora of sites with very graphical interactive tools for quickly searching Atlantic hurricane data by time range, locations impacted, and storm type and get quick answers.  Some I remember as being very intuitive, and offerings from tv stations, government sites, and independents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These days I know of exactly one, &lt;a href=&quot;https://coast.noaa.gov/hurricanes/&quot; rel=&quot;noreferrer&quot;&gt;https://coast.noaa.gov/hurricanes/&lt;/a&gt;.  However I find this site to be difficult to comparably difficult to navigate in finding the location, filtering, and interpreting.  I believe NOAA once offered a top-notch option at &lt;a href=&quot;http://hurricane.csc.noaa.gov/hurricanes/&quot; rel=&quot;noreferrer&quot;&gt;http://hurricane.csc.noaa.gov/hurricanes/&lt;/a&gt;, but it's long gone, and I have trouble finding any others.  &lt;a href=&quot;http://www.stormreportmap.com&quot; rel=&quot;noreferrer&quot;&gt;There's great such tools that have developed for severe weather&lt;/a&gt;, and perhaps with the millions of sites out there, other good ones for hurricanes exist, and I just don't know it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even better would be if such a site also included other basins to boot.  But these days, even for the Atlantic, I usually just look through pages on like &lt;a href=&quot;http://weather.unisys.com/hurricane/&quot; rel=&quot;noreferrer&quot;&gt;Unisys Weather&lt;/a&gt; or &lt;a href=&quot;http://derecho.math.uwm.edu/models/archive/&quot; rel=&quot;noreferrer&quot;&gt;the archives&lt;/a&gt; on &lt;a href=&quot;http://derecho.math.uwm.edu/models/&quot; rel=&quot;noreferrer&quot;&gt;Clark Evans' model website&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Atlantic_hurricane_season&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia annual maps&lt;/a&gt;.  But searching for &quot;when is the last time a storm affected X&quot; has proven surprisingly hard these days.  Any help to offer? &lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2019-12-22T11:09:57.800" Title="Are there any other sites that allow users to search for historic hurricanes within a given area?" Tags="|tropical-cyclone|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="14233" PostTypeId="1" CreationDate="2018-05-22T11:09:39.413" Score="4" ViewCount="41" Body="&lt;p&gt;I am involved on a project that aims to analyze data from road weather stations, like the ones you can see from a German site here: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.dwd.de/EN/ourservices/bufr_extensions_national/bufr_extensions_national.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.dwd.de/EN/ourservices/bufr_extensions_national/bufr_extensions_national.html&lt;/a&gt;&#xA;&lt;a href=&quot;https://opendata.dwd.de/weather/weather_reports/road_weather_stations/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://opendata.dwd.de/weather/weather_reports/road_weather_stations/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone know where I can find this kind of information from other countries? I am specially interested in analyzing Water Film Thickness.&lt;/p&gt;&#xA;" OwnerUserId="13015" LastEditorUserId="595" LastEditDate="2018-05-29T11:23:50.937" LastActivityDate="2018-05-29T11:23:50.937" Title="Where to find meteorological data from road stations?" Tags="|meteorology|measurements|field-measurements|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14238" PostTypeId="1" AcceptedAnswerId="14266" CreationDate="2018-05-22T19:49:06.127" Score="3" ViewCount="364" Body="&lt;p&gt;Just based on my previous experiences a wetter snow, in general, has larger flakes.  Some online sources say that raindrops do have a maximum size before they start to break apart when surface tension can no longer withstand air resistance, however the maximum size of a snowflake is less defined (1&amp;amp;2).  One source also states that light winds and a wetter snow is more conducive to larger flakes because the light wind helps keep them from breaking into pieces, and the additional moisture creates a film which helps the flakes stick together (2).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand that it may be difficult to measure a snowflake before it melts and that may be why the only non-confirmed size that I have found is from the 2014 Guinness Book of World Records of an eye witness account in 1887 of a snowflake 15&quot; wide by 18&quot; deep (3).   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my question is twofold:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Is there a theoretical limit to how large a single snowflake can be?&lt;/li&gt;&#xA;&lt;li&gt;If there is a reliable way to measure snowflakes, what is the largest&#xA;snowflake ever measured?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Sources:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://www.theweatherprediction.com/habyhints/261/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.theweatherprediction.com/habyhints/261/&lt;/a&gt;     &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.reddit.com/r/askscience/comments/32e2nf/what_is_the_maximum_size_of_a_raindrop/?st=jhi2ljz8&amp;amp;sh=25942d8e&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.reddit.com/r/askscience/comments/32e2nf/what_is_the_maximum_size_of_a_raindrop/?st=jhi2ljz8&amp;amp;sh=25942d8e&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.reference.com/science/big-can-snowflakes-a119e8a009c4d4ac&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.reference.com/science/big-can-snowflakes-a119e8a009c4d4ac&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2018-05-24T07:15:01.023" Title="Is there a maximum size for a single snowflake?" Tags="|meteorology|precipitation|snow|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14239" PostTypeId="1" CreationDate="2018-05-23T00:49:32.313" Score="1" ViewCount="214" Body="&lt;p&gt;Building off of another question I recently asked (&lt;a href=&quot;https://earthscience.stackexchange.com/questions/14214/is-there-sand-in-antarctica&quot;&gt;Is there sand in Antarctica?&lt;/a&gt;) I want to ask a broader question coming from the same motive described there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there desert sands that experience blizzards? I know of places with sand that experience blizzards, for example certain beaches in the Adirondacks or Great Lakes of northeastern USA. But what about desert sands?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other question identifies Antarctic desert sands, and a comment even notes that where Chicago is now was once covered in desert sands. The latter point made me realize though, do blizzards (snow storms with high winds, to be specific) occur in these sand dune areas? If yes, then are there numerous examples of where this occurs, or is it a somewhat rare thing?&lt;/p&gt;&#xA;" OwnerUserId="4789" LastActivityDate="2018-05-23T05:12:09.937" Title="Are there areas of desert sands which experience blizzards?" Tags="|meteorology|desert|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14241" PostTypeId="2" ParentId="14231" CreationDate="2018-05-23T03:28:09.163" Score="4" Body="&lt;p&gt;There is this atlas for the North Indian Ocean basin - &lt;a href=&quot;http://www.rmcchennaieatlas.tn.nic.in/abouteatlas.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;Indian Ocean Cyclone Atlas&lt;/a&gt; and while I am not sure about the cyclone tracks for the pre satellite era cyclones the site is comprehensive and covers all cyclones in the Indian Ocean up to the current period. After you register yourself here - &lt;a href=&quot;http://www.rmcchennaieatlas.tn.nic.in/Registration.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;Registration &lt;/a&gt; then you can view the cyclone tracks. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a sample of cyclone tracks between 2012 and 2016&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HCky8.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HCky8.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-12-22T11:09:57.800" LastActivityDate="2019-12-22T11:09:57.800" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14244" PostTypeId="2" ParentId="14239" CreationDate="2018-05-23T05:12:09.937" Score="3" Body="&lt;p&gt;It really depends on what you consider &quot;desert sands&quot;.  For instance, Sand Mountain in Nevada &lt;a href=&quot;https://en.wikipedia.org/wiki/Sand_Mountain_(Nevada)&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Sand_Mountain_(Nevada)&lt;/a&gt; is an area of sand dunes in a desert, and occasionally experiences snowstorms that reach blizzard conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although most of the lower elevations are sagebrush steppe, there are other areas of sand (and dry lake beds &amp;amp;c) in the Great Basin, and the area experiences winter cold, occasional snow, and high winds.  I'd expect similar conditions in the Gobi Desert, though I have no first-hand experience: &lt;a href=&quot;https://en.wikipedia.org/wiki/Gobi_Desert&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Gobi_Desert&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2018-05-23T05:12:09.937" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14246" PostTypeId="1" CreationDate="2018-05-23T13:21:25.163" Score="3" ViewCount="28" Body="&lt;p&gt;I have been looking for information regarding the total amount of water that evaporates from terrestrial systems and found some global estimates like this one&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.waterandclimatechange.eu/evaporation/average-monthly-1985-1999&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.waterandclimatechange.eu/evaporation/average-monthly-1985-1999&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the units are mm/year but that doesn't mean much without the area. Are there any estimates of evapotranspiration that are available? Or how could I calculate evapotranspiration by area using maps such as the ones I have linked to?&lt;/p&gt;&#xA;" OwnerUserId="3061" LastActivityDate="2018-05-23T14:10:22.463" Title="Data of terrestrial evapotranspiration over large areas?" Tags="|meteorology|evaporation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14247" PostTypeId="1" CreationDate="2018-05-23T14:03:34.983" Score="4" ViewCount="111" Body="&lt;p&gt;In a recent discussion with a farmer, the (at least in northwestern Germany) &quot;popular&quot; topic of nitrate infiltration into groundwater came up. The general view is that lots of fields receive more nitrate fertilizer than the plants can use, this then percolates through the ground and eventually shows up in the groundwater that is also used as drinking water. So far so plausible. Raised nitrate content in groundwater is indeed often observed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One should probably add that in this area, a lot of agriculture is raising of hogs and cattle, consequently much of the fertilizer is manure that has a (compared to commercial fertilizer) low NPK content and is thus not worth to transport over far distances. So there's an incentive to dispose on ones own fields, nearby.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, this farmer claimed that the nitrate content we see now is decades old, that the bylaws and controls as well as agricultural practices in place now work. Is this true? Does nitrate penetrate ground so slowly? The only mechanism here I could think of that nitrate is adsorbed and desorbed on minerals in the ground, sort of like in chromotography column.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If neccessary, I can provide more figures for nitrate content of specific wells, groundwater table etc - but I don't think it's neccessary since I want a qualitative answer wether or not such a slow infiltration is plausible at all.&lt;/p&gt;&#xA;" OwnerUserId="117" LastActivityDate="2018-05-24T02:11:55.573" Title="Does nitrate take a particular long time to percolate from surface into groundwater?" Tags="|hydrology|groundwater|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14248" PostTypeId="2" ParentId="14246" CreationDate="2018-05-23T14:10:22.463" Score="3" Body="&lt;p&gt;Millimeters per year measurements have an area component built into them, they're actually in cubic millimeters per square millimeter. So one millimeter of rainfall is enough to cover the given area that rainfall is for to an average depth of one millimeter. For example if the area is a 100 square kilometer catchment then 1mm of rainfall is 100,000,000 cubic millimeters (also millilitres), or 100,000 litres of water. Evapotranspiration is measured using exactly the same unit conventions. Hope that helps.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-05-23T14:10:22.463" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14249" PostTypeId="1" AcceptedAnswerId="14513" CreationDate="2018-05-23T14:22:19.397" Score="5" ViewCount="261" Body="&lt;p&gt;There are a lot of variations of basic, first-order hydrology models to estimate runoff from rainfall with a few other parameters. From what I can tell, most very basic rainfall-runoff models use one of the following methods at their core: the&#xA;&lt;a href=&quot;https://engineering.purdue.edu/mapserve/LTHIA7/documentation/scs.htm&quot; rel=&quot;noreferrer&quot;&gt;SCS Curve Number method&lt;/a&gt;, the &lt;a href=&quot;https://www.lmnoeng.com/Hydrology/rational.php&quot; rel=&quot;noreferrer&quot;&gt;Rational method&lt;/a&gt;, and the &lt;a href=&quot;https://www.hydrocad.net/pdf/NY-Simple-Method.pdf&quot; rel=&quot;noreferrer&quot;&gt;Simple method&lt;/a&gt;. I'm trying to understand: &lt;strong&gt;how do these methods differ, and are there other methods used at the core of basic, first-order hydrology models?&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From what I can tell, the SCS Curve Number method is only slightly different from the Rational method in that it uses a Curve Number (based on land use and soils) rather than a Runoff Coefficient (based on soil and basin slope). The two are both event-based models, at least in their initial design.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Simple method appears to be a lot like the Rational method but the former is for estimating pollutant loading (using pollutant coefficients and runoff) while the latter is for estimating runoff (using runoff coefficients and rainfall). I could see the two being coupled, but they don't appear to have any redundancy in their use.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Considering the summary of my findings, &lt;strong&gt;can these methods be described together as &quot;empirical models&quot;&lt;/strong&gt; given that they are all based on empirically derived coefficients (either Curve Number values, runoff coefficients, or pollutant coefficients)?&lt;/p&gt;&#xA;" OwnerUserId="4789" LastActivityDate="2018-06-28T17:27:47.353" Title="What's the difference between these most basic, first-order models for estimating runoff?" Tags="|hydrology|models|storms|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14251" PostTypeId="1" CreationDate="2018-05-23T15:06:17.807" Score="3" ViewCount="269" Body="&lt;p&gt;I want to know how to determine water table height and phreatic line in earthen dam with rock fill and clay core.&lt;/p&gt;&#xA;" OwnerUserId="13026" LastActivityDate="2018-05-24T20:48:52.347" Title="Earthen dam with rock fill and clay core" Tags="|dams|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14252" PostTypeId="2" ParentId="14247" CreationDate="2018-05-23T15:11:28.037" Score="3" Body="&lt;p&gt;I know in New Zealand we have a number of soils you can't raise dairy herds on because the nitrate in their urine strips too many nutrients too fast, to the point where one can tell where the cow urinated a couple of weeks ago because that patch of grass is dying from several different deficiencies simultaneously. My understanding is that dairy cows are, hands-down, &lt;em&gt;the&lt;/em&gt; worst farm animal for this because they stand still when voiding and dump up to 15 litres of moderate-high nitrate liquid waste at a time which all goes effective straight down through the soil column robbing it of nutrients along the way. On the other hand there are also some soils, generally in more arid areas, where nitrate doesn't migrate right through the soil column at all but concentrates in the subsoil as a visible, white, salty, horizon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a rule the more water retentive the soil the longer water soluble compounds like nitrate will take to work down into the ground at a given water input. There are also some chemical interactions that will bind nitrate and slow it down more than you might expect we need study them in my soil fertility papers but I can't think what they are right now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But to answer your question, usually soluble soil ions (which nitrate is) move on a timescale of days, weeks or maybe months, but not decades. We wouldn't need to apply slow-release nitrate fertilisers annually if it didn't migrate through at least the top-soil relatively rapidly.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-05-23T15:11:28.037" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14255" PostTypeId="2" ParentId="13452" CreationDate="2018-05-23T15:56:05.407" Score="2" Body="&lt;p&gt;It would certainly be possible to construct a series of balloons that reached neutral buoyancy at different altitudes, so in that sense the answer is &quot;yes&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not sure whether there's necessarily any correlation between balloon size and altitude, except in that a given balloon will expand as it rises.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2018-05-23T15:56:05.407" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14257" PostTypeId="2" ParentId="14251" CreationDate="2018-05-23T18:58:40.470" Score="3" Body="&lt;p&gt;Okay have a look at &lt;a href=&quot;http://yo-1.ct.ntust.edu.tw/jge/files/articlefiles/v8i120130617369341087.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; it may be some use, it's the &lt;em&gt;Journal of GeoEngineering, Vol. 8, No. 1 April 2013 Pgs 27-32&lt;/em&gt; so you may be able to get a hard copy if the link fails, it talks about clay core dams and seepage calculations thereof, including phreatic pathway estimation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I remember correctly rock fill in earth dams is treated as earth for the purposes of working out seepage lines etc... as it is generally small enough (particle size), relative to the dam as a whole, to have little or no effect on total mean permeability.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-05-23T18:58:40.470" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14258" PostTypeId="1" CreationDate="2018-05-23T19:25:57.520" Score="0" ViewCount="1251" Body="&lt;p&gt;Can the tides at night be consistently higher than in the daytime in southwest Australia in the port of Fremantle?&#xA;Also, what is the explanation for the tides being significant during a part of the year, and then disappear.&lt;/p&gt;&#xA;" OwnerUserId="12569" LastEditorUserId="111" LastEditDate="2018-05-26T00:56:17.637" LastActivityDate="2018-05-26T00:56:17.637" Title="Can tides at night by consistently higher than in the daytime?" Tags="|ocean|tides|" AnswerCount="1" CommentCount="9" ClosedDate="2018-05-24T13:59:01.237" ContentLicense="CC BY-SA 4.0" />
  <row Id="14259" PostTypeId="1" AcceptedAnswerId="18911" CreationDate="2018-05-23T20:30:20.120" Score="15" ViewCount="624" Body="&lt;p&gt;There was lava in the area near the wells that the Puna Geothermal Venture facility created.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The plant has nine wells that run as deep as 8,000 feet, according to Wil Okabe, managing director for the County of Hawaii. -&lt;a href=&quot;https://www.washingtonpost.com/national/volcanic-activity-threatens-hawaii-geothermal-plant-long-at-center-of-resident-concerns/2018/05/11/61c55c0a-5533-11e8-abd8-265bd07a9859_story.html?utm_term=.36ba1fbf76af&quot; rel=&quot;noreferrer&quot;&gt;Washington Post&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;8,000 feet is really quite deep. While I understand that those are not the deepest wells created for geothermal energy, in Hawaii that seems deep enough to get to where lava would also be pooling. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, it would be deep enough to hit the pool at one of the main volcanoes.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Rocks that are moving upward in the mantle beneath Hawai`i begin to melt about 40 to 60 miles (60 to 100 km) depth. The molten rock, called magma , rises because of its relatively low density. The magma &quot;ponds&quot; in a reservoir 1 to 4 miles (2 to 6 km) beneath the summit. &lt;a href=&quot;https://www.nps.gov/havo/faqs.htm&quot; rel=&quot;noreferrer&quot;&gt;https://www.nps.gov/havo/faqs.htm&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In addition to the availability of lava in the area near the wells, it seems that geothermal energy has also been linked to earthquake activity in the past.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;An analysis of earthquakes in the area around the Salton Sea Geothermal Field in southern California has found a strong correlation between seismic activity and operations for production of geothermal power -&lt;a href=&quot;https://news.ucsc.edu/2013/07/geothermal-earthquakes.html&quot; rel=&quot;noreferrer&quot;&gt;UC Santa Cruz&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Moreover, the facility itself is basically right on the location that the set of fissures opened up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://www.gannett-cdn.com/media/2018/05/22/USATODAY/USATODAY/636625963293443678-052218-Hawaii-volcano-power-plant-Online.png&quot; alt=&quot;Puna GeoThermal Venture Map&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As location of seismic activity is in question here, I also found a map from the US Geological Survey with 30 days of activity for this portion of Hawaii.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/w0lPO.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/w0lPO.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;The largest circles are a 5.4 and 6.9, the smallest ones are equal to or greater than 2.5.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given the proximity of the facility, as well as the fact that these wells were not only near underground lava, but also have been known in other areas to produce earthquakes, what roll, if any, could the Puna GeoThermal Venture have played in the recent fissure activity in Pahoa, Hawaii?&lt;/p&gt;&#xA;" OwnerUserId="13029" LastEditorUserId="13029" LastEditDate="2019-02-20T19:27:01.870" LastActivityDate="2021-10-09T02:58:40.790" Title="Did the Geothermal Power Plant contribute to Pahoa's Lava Fissures?" Tags="|volcanology|earthquakes|geothermal-heat|volcanic-hazard|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14260" PostTypeId="2" ParentId="14258" CreationDate="2018-05-23T20:43:28.740" Score="3" Body="&lt;p&gt;I find the statement in the question difficult to believe.Tides have a pretty cyclical period and I doubt the resulting effect is a day-night difference unless only S1 and S2 tidal constituents are important in that location, which I find very unlikely.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact, the portal&#xA;&lt;a href=&quot;https://www.tide-forecast.com/locations/Fremantle-Australia/tides/latest&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.tide-forecast.com/locations/Fremantle-Australia/tides/latest&lt;/a&gt;&#xA;shows the high tide being larger during the day for the rest of the month of May 2018.&lt;a href=&quot;https://i.stack.imgur.com/b4TM5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/b4TM5.png&quot; alt=&quot;may tide&quot;&gt;&lt;/a&gt;&#xA;That behavior changes in time as one would expect. The dominant frequencies at this location are diurnal tides (mostly a single high tide and low tide per day). The main diurnal tides have a period around 24 hours and in this case the dominant periods are slightly larger than 24 hours. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can download the hourly data from: &lt;a href=&quot;http://uhslc.soest.hawaii.edu/data/netcdf/fast/hourly/h175.nc&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://uhslc.soest.hawaii.edu/data/netcdf/fast/hourly/h175.nc&lt;/a&gt;&#xA;and the resulting time series goes from 1984 to now. Here is the time series for the year 2017. There is no time at which the tide &quot;dissappears&quot;.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/NYhOs.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NYhOs.png&quot; alt=&quot;SL&quot;&gt;&lt;/a&gt;&#xA;The resulting harmonic analysis (using t_tide) shows that the tidal constituents with amplitudes over about 5 cm are:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Constituent  Period (h)  Magnitude (m)&#xA;   O1         25.82      0.1206    &#xA;   K1         23.93      0.1667    &#xA;   M2         12.42      0.0525   &#xA;   S2         12.00      0.0465   &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The dominant constituents are K1 and O1, with comparable amplitudes. The resulting effect of the two main diurnal frequencies is a period slightly over 24 hours. The effect of the semidiurnal constituents (M2, S2) is smaller and can be seen in the first time series as slight humps in May 24-27.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;T_tide: Pawlowicz, R., B. Beardsley, and S. Lentz, &quot;Classical Tidal &#xA;&quot;Harmonic Analysis Including Error Estimates in MATLAB &#xA; using t_tide&quot;, Computers and Geosciences, 28, 929-937 (2002).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="111" LastActivityDate="2018-05-23T20:43:28.740" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="14261" PostTypeId="2" ParentId="14247" CreationDate="2018-05-24T02:11:55.573" Score="3" Body="&lt;p&gt;Nitrate is an anion and thus tends to be poorly adsorbed to soils and thus is transported at approximately the rate of the recharging water. Thus, the transport below the root zone depends largely on the amount of precipitation and on the amount of evapotranspiration within the root zone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The situation with fertilizer and urine is much more complicated, however, because there are multiple nitrogen species and transformations that occur in the nitrogen cycle. Nitrogen fertilizer may be applied in a number of forms including urea, ammonia, nitrate, or mixtures of these. Urea is commonly used in my area, anyway, because of its low cost.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Urea is converted to ammonium in the soil. Urea and ammonium are cations and strongly sorbed to soil particles. Ammonium can be volatilized and lost as gaseous ammonia but is also transformed to nitrate by nitrification.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nitrate is the main form of nitrogen that is assimilated by plants. It can also be transformed to nitrogen gas by denitrifying bactera. Some plants such as pulses (e.g. peas and beans) have a symbiotic relationship with bacteria in their root nodules that fix nitrogen in soil gas to ammonium, which is then used converted to nitrate by nitrification and used by the plants. Nitrogen is also released to soil by decomposing plant matter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JiQWq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JiQWq.png&quot; alt=&quot;Nitrogen cycle&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are other nitrogen species, but they tend to be transient products along the chain of reactions described above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the farmer is partially correct, much of the nitrogen in the soil is in a form that is not readily available for uptake by plants or by leaching to groundwater. But is incorrect to say that current impacts are only due to old nitrogen and that the problem has been solved. As long as nitrogen is being added in one of the various forms, the transformations are ongoing, nitrate is being produced, and this nitrate has the potential to pollute groundwater. Note, also that ammonium and nitrate can be transported through surface water, either sorbed to sediments or dissolved, which can be an even bigger pollution issue.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a &lt;a href=&quot;http://vro.agriculture.vic.gov.au/dpi/vro/vrosite.nsf/pages/soilhealth_nitrogen-cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;link to a video on nitrogen transformations in agricultural soils&lt;/a&gt; and to &lt;a href=&quot;http://vro.agriculture.vic.gov.au/dpi/vro/vrosite.nsf/pages/soilhealth_nitrogen-cycle_transcript&quot; rel=&quot;nofollow noreferrer&quot;&gt;notes on the video&lt;/a&gt;, for those that prefer to read. &lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2018-05-24T02:11:55.573" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14262" PostTypeId="2" ParentId="13452" CreationDate="2018-05-24T03:01:59.253" Score="1" Body="&lt;p&gt;I assume you would like a chain of balloons going into space. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Our current balloon material technology has examples (see below) from the surface up to 53km and then for space to go 100km and beyond. The range where R&amp;amp;D of balloon materials would be needed is from 53km to 100km.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Toy balloons can reach 10km. &lt;/li&gt;&#xA;&lt;li&gt;The highest hot-air-balloon flight reached &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Flight_altitude_record&quot; rel=&quot;nofollow noreferrer&quot;&gt;21km&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;For a manned helium balloon, the highest is &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Flight_altitude_record&quot; rel=&quot;nofollow noreferrer&quot;&gt;41km&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;A weather balloon, as you indicated has reached &lt;a href=&quot;https://en.m.wikipedia.org/wiki/High-altitude_balloon&quot; rel=&quot;nofollow noreferrer&quot;&gt;53.0 km&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;The Karman Line between our atmosphere and space is at &lt;a href=&quot;https://en.m.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_line&quot; rel=&quot;nofollow noreferrer&quot;&gt;100km&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;NASA’s Project Echo reached &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Project_Echo&quot; rel=&quot;nofollow noreferrer&quot;&gt;1,519 to 1,687 km&lt;/a&gt; with Echo 1A.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Now that said, there would be other problems to consider besides balloon materials.  =)&lt;/p&gt;&#xA;" OwnerUserId="12990" LastActivityDate="2018-05-24T03:01:59.253" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14263" PostTypeId="1" AcceptedAnswerId="14265" CreationDate="2018-05-24T03:22:49.217" Score="11" ViewCount="3306" Body="&lt;p&gt;Is it possible that the geomagnetic field reversal with a weakened geomagnetic field over centuries if not thousands of years (according to the Pittsburgh simulation: &lt;a href=&quot;https://www.psc.edu/science/glatzmaier.html&quot; rel=&quot;noreferrer&quot;&gt;https://www.psc.edu/science/glatzmaier.html&lt;/a&gt;) and exposure both to cosmic radiation, solar storms and continuous meteor bombardment, multiple &quot;norths and souths&quot; and deregulation of the biospheric clocks e.g. migratory paths of birds and animals using the geomagnetic field for navigation etc., raised volcanic and tectonic activities led to the extinction of Dinosaurs? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Between Matuyama Epoch of 243 million ya to 68 million years ago to Brunhes-Matuyama current epoch&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XeUJf.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XeUJf.jpg&quot; alt=&quot;Jacobs, John Arthur. 1994. Reversals of the earth&amp;#39;s magnetic field. Cambridge [u.a.]: Cambridge Univ. Press. p 63&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="9620" LastActivityDate="2018-05-24T11:47:07.677" Title="Is it possible that the geomagnetic field reversal led to the extinction of Dinosaurs?" Tags="|geomagnetism|mass-extinction|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14264" PostTypeId="2" ParentId="14263" CreationDate="2018-05-24T04:41:12.810" Score="13" Body="&lt;p&gt;It's a commonly-proposed theory that geomagnetic reversals cause extinction events, but &lt;a href=&quot;https://en.wikipedia.org/wiki/Geomagnetic_reversal#Effects_on_biosphere&quot; rel=&quot;noreferrer&quot;&gt;there's no evidence for it&lt;/a&gt;.  There aren't enough mass extinction events for any sort of statistical analysis, and there are a number of geologic processes that can give the illusion of simultaneous reversal and extinction.  In particular, an erosion event can erase both the actual extinction event and the actual time of reversal, leaving them apparently both happening at the same time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further complicating things is the low resolution of the historic timeline, compared to the short duration of reversal events.  As an example, the timing of the extinction of the dinosaurs is known to, at best, &lt;a href=&quot;http://www.cugb.edu.cn/uploadCms/file/20600/20131028144132060.pdf&quot; rel=&quot;noreferrer&quot;&gt;a few tens of thousands of years&lt;/a&gt;, yet a reversal can take only a few hundred years.  Two events that &lt;em&gt;look&lt;/em&gt; simultaneous (such as an extinction and a reversal) can actually be separated by thousands of years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the specific case of the dinosaurs, there doesn't appear to be evidence of a reversal at the time of extinction.&lt;/p&gt;&#xA;" OwnerUserId="2643" LastActivityDate="2018-05-24T04:41:12.810" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14265" PostTypeId="2" ParentId="14263" CreationDate="2018-05-24T05:25:18.193" Score="19" Body="&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/14264/6298&quot;&gt;Mark's answer&lt;/a&gt; is correct, but in my opinion is not clear enough. Let's make it a bit simpler:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is it possible that the geomagnetic field reversal led to the extinction of Dinosaurs?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;NO, DEFINITELY NOT&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's why:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cause for the K-Pg extinction event (in which many living species, including dinosaurs, died) is well known: volcanic eruptions (the Deccan Traps) and an impact (Chicxulub). It's still debated which one contributed more to the event, or whether one is the result of the other, but that's not the point. It's not related to magnetism.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact, all big five extinction events in Earth's history are well linked to increased volcanic activity (including the Siberian Traps at the time of the largest extinction, the P-T extinction event aka the &quot;great dying&quot;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, magnetic reversals happen all the time. Yet, there are no extinctions related to them. Your question also lists several incorrect assumptions:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;continuous meteor bombardment&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Incorrect: Geomagnetic reversals have no effect on whether we are bombarded by meteors or not.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;raised volcanic and tectonic activities &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Incorrect: Geomagnetic reversals are not linked to raised volcanic or tectonic activity.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Between Matuyama Epoch of 243 million ya to 68 million years ago to Brunhes-Matuyama current epoch&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;These are recent magnetic epochs from the Pleistocene, only a few million years ago. Thus unrelated to the K-Pg extinction event (or any event for that matter).&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2018-05-24T11:47:07.677" LastActivityDate="2018-05-24T11:47:07.677" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14266" PostTypeId="2" ParentId="14238" CreationDate="2018-05-24T07:15:01.023" Score="3" Body="&lt;p&gt;According to Caltech physics professor Kenneth G. Libbrecht's site &lt;a href=&quot;http://snowcrystals.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;SnowCrystals.com&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;http://www.snowcrystals.com/monster/monster.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;This monster&lt;/a&gt; is, to my knowledge, the largest snow crystal ever photographed. It measures 10.1 mm (0.4 inches) from tip to tip (averaged over the three axes). ... Note that this is a snow crystal: a single crystal of ice ... Larger snowflakes have been reported, but those were puffballs made of huge numbers of individual snow crystals stuck together. During very calm conditions, these puffballs can grow into pancake-shaped agglomerations as large as a dinner plate &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;He has a paper &lt;a href=&quot;http://www.snowcrystals.com/science/contents/PhysicalDynamicsOfIceCrystalGrowth.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Physical Dynamics of Ice&#xA;Crystal Growth&lt;/a&gt;, but I don't see any discussion of theoretical maximum sizes of crystals or agglomerations.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2018-05-24T07:15:01.023" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14267" PostTypeId="1" CreationDate="2018-05-24T17:33:27.907" Score="7" ViewCount="2628" Body="&lt;p&gt;I've noticed that geology and related fields use mega-annum (Ma) instead of mega-year (Myr) as the unit for 1 million years.  Why is that?  Is an &quot;annum&quot; different from a &quot;year&quot; in geology?&lt;/p&gt;&#xA;" OwnerUserId="8339" LastEditorUserId="111" LastEditDate="2018-05-25T02:49:58.463" LastActivityDate="2020-11-19T15:40:12.260" Title="Why do the earth sciences use mega-annum instead of mega-year?" Tags="|geology|time|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14268" PostTypeId="1" AcceptedAnswerId="19106" CreationDate="2018-05-24T17:46:33.400" Score="5" ViewCount="129" Body="&lt;p&gt;Solar Flares are a commonly discussed phenomenon, which have effects ranging from geomagnetic storms to radio disruptions to absolutely nothing noticeable. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given that part of the core of the Earth is molten, and magnetic, is there any evidence either way of the core of the Earth producing 'geoflares' like Solar Flares?&lt;/p&gt;&#xA;" OwnerUserId="13036" LastEditorUserId="39" LastEditDate="2018-05-24T19:53:28.577" LastActivityDate="2020-02-02T23:42:23.140" Title="Does the Earth 'Flare' like the Sun does?" Tags="|geophysics|core|solar-terrestrial-physics|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14269" PostTypeId="2" ParentId="14251" CreationDate="2018-05-24T20:48:52.347" Score="0" Body="&lt;p&gt;This problem can be solved using finite element modelling, e.g. using software such as &lt;a href=&quot;https://www.geoslope.com/products/seep-w&quot; rel=&quot;nofollow noreferrer&quot;&gt;SEEP/w&lt;/a&gt;. Here is a specific example of a dam: &lt;a href=&quot;http://downloads.geo-slope.com/geostudioresources/examples/9/0/SeepW/Seepage%20through%20an%20earth%20dam.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;PDF&lt;/a&gt; and &lt;a href=&quot;https://www.youtube.com/watch?v=8DPtUHFU0Pw&quot; rel=&quot;nofollow noreferrer&quot;&gt;YouTube&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="777" LastActivityDate="2018-05-24T20:48:52.347" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14270" PostTypeId="2" ParentId="14267" CreationDate="2018-05-24T23:55:26.213" Score="10" Body="&lt;p&gt;Both mega-annum(Ma) and mega-year(Myr) designate one million years.  The distinction is that Ma is used to designate the time before present or geohistoric dates and Myr to designate a duration or span of time.  So if you want to say a rock is dated to 10 million years before the present you would use 10 Ma, and if you want to say that a rock is 10 million years old you would use 10 Myr.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There has been debate among scientific disciplines to simply adopt Ma as the standard unit.  However, the distinction that geologists have been using to distinguish between dates and durations for decades can best be illustrated as such:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;No one objects to the storming of the Bastille on 14 July 1789 (a&#xA;  date) or to the construction of Stonehenge from 2600–1600 BC (an&#xA;  interval specified by two dates). In the case of the latter, we say&#xA;  that the job took 1000 years, not 1000 BC. The distinction between&#xA;  geohistorical dates and spans of geological time is conceptually&#xA;  analogous. There is no internal inconsistency, and the International&#xA;  System of Units (SI) rules don’t apply to dates in either case because&#xA;  points in time are not units, even if they are specified in years&#xA;  (Aubry et al., 2009). The year, moreover, is not a part of the SI. It&#xA;  cannot be a “derived unit of time,” the designation proposed by the&#xA;  task group, because under SI conventions “derived units are products&#xA;  of powers of base units” (BIPM, 2006). The base unit for time is the&#xA;  second. The task group is thus intent on fixing a problem that doesn’t&#xA;  exist and in a manner that is at odds with their stated goal of&#xA;  “adherence to SI rules.”&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The above quote is from the &lt;a href=&quot;http://www.geosociety.org/gsatoday/archive/22/2/article/i1052-5173-22-2-28.htm&quot; rel=&quot;noreferrer&quot;&gt;Geological Time Conventions and Symbols manuscript&lt;/a&gt; from 2011.  More detailed discussion can be found at this source.  This &lt;a href=&quot;http://scienceblogs.com/stressrelated/2009/09/21/how-should-geologists-abbrevia/&quot; rel=&quot;noreferrer&quot;&gt;Science Blogs article&lt;/a&gt; from 2009 has some interesting discussions regarding this issue.  &lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2018-05-24T23:55:26.213" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14271" PostTypeId="1" AcceptedAnswerId="14274" CreationDate="2018-05-25T01:41:41.973" Score="3" ViewCount="217" Body="&lt;p&gt;In &lt;a href=&quot;https://www.youtube.com/watch?v=I_0GgKfwCSk&quot; rel=&quot;nofollow noreferrer&quot;&gt;the video&lt;/a&gt; of the recent Iridium-6/GRACE-FO launch at about &lt;code&gt;T+ 33:00&lt;/code&gt; (curently at &lt;code&gt;49:00&lt;/code&gt; in the video) the 2nd stage passes over Antarctica and this is shown in the animation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I noticed a strange pattern of radial lines drawn on Antarctica, presumably near the South Pole. I remembered seeing these before and assumed them to be some kind of graphics glitch, until I saw something similar in the BBC News article &lt;a href=&quot;http://www.bbc.com/news/science-environment-44245893&quot; rel=&quot;nofollow noreferrer&quot;&gt;Giant canyons discovered in Antarctica&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are the patterns in the two images related, and what do they mean?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FD6NY.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FD6NY.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/G1A9U.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G1A9U.jpg&quot; alt=&quot;Screen Shot SpaceX Iridium-6 GRACE-FO&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RYmlE.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RYmlE.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6298" LastEditDate="2022-02-06T17:30:23.823" LastActivityDate="2022-02-06T17:30:23.823" Title="What are these radial line patterns shown in representations of antarctica?" Tags="|mapping|antarctica|satellite-oddities|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14272" PostTypeId="1" CreationDate="2018-05-25T05:51:29.653" Score="5" ViewCount="667" Body="&lt;p&gt;I refer to this article on nytimes.com: &lt;a href=&quot;https://news.ycombinator.com/item?id=17142736&quot; rel=&quot;nofollow noreferrer&quot;&gt;Every 202,500 Years, Earth Wanders in a New Direction&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;TLDR: Scientists believe the earth's orbit oscillates between circular&#xA;and more elliptical due to the gravitational pull from Jupiter (big)&#xA;and Venus (close). It takes 405k years to complete a cycle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The big question: could this affect climate-change? Could it make colder winters, hotter summers or just more extreme weathers? Changing Gulf stream? &lt;/p&gt;&#xA;" OwnerUserId="13037" LastEditorDisplayName="user12525" LastEditDate="2019-04-25T08:29:11.387" LastActivityDate="2019-04-25T08:29:11.387" Title="Every 202,500 years, Earth wanders in a new direction; does it affect climate?" Tags="|climate-change|climate|earth-observation|sun|milankovitch-cycles|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14273" PostTypeId="2" ParentId="14272" CreationDate="2018-05-25T06:32:15.843" Score="9" Body="&lt;p&gt;Milankovitch cycles do affect climate on Earth. There are several cycles. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Variations in &lt;a href=&quot;https://en.wikipedia.org/wiki/Orbital_eccentricity&quot; rel=&quot;noreferrer&quot;&gt;eccentricity&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Axial_tilt&quot; rel=&quot;noreferrer&quot;&gt;axial tilt&lt;/a&gt;, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Precession&quot; rel=&quot;noreferrer&quot;&gt;precession&lt;/a&gt; of the Earth's&#xA;  orbit resulted in cyclical variation in the solar radiation reaching&#xA;  the Earth, and that this orbital forcing strongly influenced climatic&#xA;  patterns on Earth.&quot;&#xA;  source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;noreferrer&quot;&gt;wikipedia&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Scientists of Pleistocene's climate evolution strongly correlate Milankovitch cycles with glacial/interglacial periods, affecting the Gulf Stream Current.&lt;br&gt;&#xA;Other factors of Earth's internal system, such as volcanic events do affect climate, but changes in the magnitude of solar radiation are a well known climatic variability generator.&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorUserId="28050" LastEditDate="2018-05-25T12:12:38.440" LastActivityDate="2018-05-25T12:12:38.440" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14274" PostTypeId="2" ParentId="14271" CreationDate="2018-05-25T06:56:51.403" Score="5" Body="&lt;p&gt;I can't be sure, but I strongly suspect that the radial lines in the first two images are the result of a bug in the software used to draw the map, probably resulting from vector polygons that are described in an inappropriate coordinate system going around, or too close to, the south pole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's impossible to guess at the meaning of the blue lines in the third image without any caption or context, but from referring back to your link for the article that you took it from, my guess would be that the lines show the tracks of the flights that gathered the data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;No, they are not related to each other.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2018-05-25T06:56:51.403" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14275" PostTypeId="2" ParentId="236" CreationDate="2018-05-25T08:03:56.337" Score="5" Body="&lt;p&gt;Strictly speaking, the Earth will never cease to rotate in the technical sense... not while Earth is intact at least. No matter what the Earth might eventually become tidally locked with, whether the Moon or the Sun, it will be rotating, at the same rate as either the Moon's or the Sun's orbital period. For example the moon is tidally locked with the Earth, which means its rotation rate is equal to its orbital period, so it always shows (roughly) the same face, although it wobbles on a regular pattern during each orbit, showing somewhat closer to 60% of its surface area to us rather than a flat 50%.&lt;/p&gt;&#xA;" OwnerUserId="13038" LastActivityDate="2018-05-25T08:03:56.337" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14277" PostTypeId="1" CreationDate="2018-05-21T20:20:50.727" Score="12" ViewCount="102" Body="&lt;p&gt;Ski-mountaineering in the Pacific Northwest I am frustrated that the snow pack isn't refreezing at night.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is about a 20F difference between the day and night temperatures in Seattle. Looking at forecasts for Mt. Rainier and Mt. Baker, the night temperature looks to be the same or sometimes even  warmer. I think I have seen these kinds of forecasts even when the sky is clear, when I would expect the snow pack to release a lot of longwave radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is going on here? &lt;/p&gt;&#xA;" OwnerDisplayName="DavidG25" LastActivityDate="2018-08-14T13:10:04.047" Title="Why is the diurnal temperature range on the Cascade volcanoes so small?" Tags="|meteorology|mountains|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14279" PostTypeId="2" ParentId="14267" CreationDate="2018-05-26T05:58:46.313" Score="6" Body="&lt;p&gt;&lt;strong&gt;annum (ka, Ma, Ga)&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Time before present. A point of time in the geological past, measured backwards from now. Often, “now” is defined as the year 1950.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;year (kyr, Myr, Gyr)&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A measure of duration, not necessarily age and not necessarily measured from the present time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;examples&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The fossil is dated to 110±2 Ma.&lt;/li&gt;&#xA;&lt;li&gt;According to zircon dating, the granite crystallised at ~30 Ma.&lt;/li&gt;&#xA;&lt;li&gt;The volcano was erupting intermittently for 10 kyr.&lt;/li&gt;&#xA;&lt;li&gt;The Jurassic period lasted for 56 Myr, starting at 201 Ma and 145 Ma.&lt;/li&gt;&#xA;&lt;li&gt;The Jurassic period lasted for 56 Myr, starting 201 Myr ago and ending 145 Myr ago.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2020-02-23T03:00:42.240" LastActivityDate="2020-02-23T03:00:42.240" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14280" PostTypeId="1" CreationDate="2018-05-26T08:26:12.163" Score="8" ViewCount="206" Body="&lt;p&gt;&lt;a href=&quot;https://twitter.com/BMcNoldy/status/999722611297972224&quot; rel=&quot;noreferrer&quot;&gt;This tweet&lt;/a&gt; from Brian McNoldy includes a graph suggesting that tropical cyclones are typically getting named earlier in the year in the Atlantic:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7xgim.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7xgim.jpg&quot; alt=&quot;TC earliest name&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the causes for this?&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-05-26T17:18:02.717" LastActivityDate="2018-05-27T05:36:51.823" Title="Why are tropical cyclones forming earlier in the North Atlantic basin?" Tags="|tropical-cyclone|data-analysis|atlantic|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="14281" PostTypeId="2" ParentId="14280" CreationDate="2018-05-26T13:17:44.720" Score="4" Body="&lt;p&gt;The shift appears to match up to a large change in the number of cyclones that peak as tropical storms in the early part of the TC season (here defined as March-July), shown by the blue (tropical storms) versus purple (hurricanes) in this graph (made using the &lt;a href=&quot;https://www.nhc.noaa.gov/data/&quot; rel=&quot;nofollow noreferrer&quot;&gt;HURDAT2 dataset from NHC&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IhuZv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IhuZv.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;It appears that a large part of the increase in tropical storms lines up with a coincident decrease in tropical depressions (shown in green).&lt;/strong&gt;&lt;br&gt;&#xA;It's notable that tropical depressions only start appearing in the dataset starting in 1963.  I don't know it for a fact, but because the timing lines up &lt;a href=&quot;http://noaasis.noaa.gov/NOAASIS/ml/40yearsa.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;with the advent of satellite weather data&lt;/a&gt; it suggests TDs may have been added once satellite offered a better picture to find and analyze weaker systems.&lt;br&gt;&#xA;Therefore, it would seem one possible theory might be that there was an initial predilection to hold less organized systems at tropical depression status, but as data has increased from hurricane hunters, satellite resolution upgrades, and additional/more rapid data reports, more of these systems were progressively graded as tropical storms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looking into the data at full resolution, it appears the trend may be greatest in weak and moderate tropical storms (focus on the lesser change in dark blue colors, and in most of the pink bands):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Dvj7x.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Dvj7x.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Does this pattern also match the rest of the year?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd suggest yes and no.  Here's the corresponding graph for the late parts of the season:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lRgyS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lRgyS.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So it looks like:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Tropical storms are still on the upswing in the late season, just not nearly as much (the trend line for early season goes from 0.5 to 2.5, for late season it goes from 1 to 2).&lt;/li&gt;&#xA;&lt;li&gt;Cyclones maxing as tropical depressions have also sharply dropped away in the late season, closely matching the early season pattern (indeed, late season TDs were less to start with, in parallel with the smaller TS increase).&lt;/li&gt;&#xA;&lt;li&gt;Also note that the number of hurricanes themselves have increased in the late season by over 50% (while remaining fairly constant in the early season).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;You can look into the trends in each storm type in the following set of graphs:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;TD/TS/HUR 50 years: &lt;a href=&quot;https://i.stack.imgur.com/IhuZv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;early&lt;/a&gt;, &lt;a href=&quot;https://i.stack.imgur.com/4AXzz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;mid&lt;/a&gt;, &lt;a href=&quot;https://i.stack.imgur.com/lRgyS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;late&lt;/a&gt;, &lt;a href=&quot;https://i.stack.imgur.com/HUC8k.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;total&lt;/a&gt;&lt;br&gt;&#xA;TS/HUR 100 years: &lt;a href=&quot;https://i.stack.imgur.com/U6PW1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;early&lt;/a&gt;, &lt;a href=&quot;https://i.stack.imgur.com/tcqag.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;mid&lt;/a&gt;, &lt;a href=&quot;https://i.stack.imgur.com/hdKNH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;late&lt;/a&gt;, &lt;a href=&quot;https://i.stack.imgur.com/0EvwL.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;total&lt;/a&gt;&lt;br&gt;&#xA;By strength full history: &lt;a href=&quot;https://i.stack.imgur.com/Dvj7x.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;early&lt;/a&gt;, &lt;a href=&quot;https://i.stack.imgur.com/3N3oF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;mid&lt;/a&gt;, &lt;a href=&quot;https://i.stack.imgur.com/dgydn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;late&lt;/a&gt;, &lt;a href=&quot;https://i.stack.imgur.com/hlEOj.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;total&lt;/a&gt;&lt;/strong&gt;&lt;br&gt;&#xA;&lt;sub&gt;&lt;sup&gt;(Note these analyses don't include 19 unnamed TCs in 1967-69 where no intensity is given in HURDAT)&lt;/sup&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Many certainly do propose climate change as a possible mechanism to shift the intensity and numbers of TCs.  Quite a few warming modeling studies have suggested there would be an increase in tropical storms.  It appears that &lt;a href=&quot;https://journals.ametsoc.org/doi/full/10.1175/BAMS-D-11-00262.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt; (Kunkel et al 2009) has some interesting discussion into the topic in the hurricanes and typhoons section.  The conclusion of:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In summary, robust detection of trends in Atlantic and western North&#xA;  Pacific TC activity is significantly constrained by data heterogeneity&#xA;  and deficient quantification of internal variability. Attribution of&#xA;  past TC changes is further challenged by a lack of consensus on the&#xA;  physical linkages between climate forcing and TC activity. As a&#xA;  result, attribution of any observed trends in TC activity in these&#xA;  basins to anthropogenic forcing remains controversial.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;seems to offer a fair reflection of the overall situation as of now in tropical cyclones and possible connections to &lt;a href=&quot;https://en.wikipedia.org/wiki/Global_warming&quot; rel=&quot;nofollow noreferrer&quot;&gt;climate change&lt;/a&gt;.  There's certainly plenty of debate over how significantly climate change is influencing the shifts seen; some will draw more conclusions than others.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regardless of whether it's due to changes in identification practices or other causes like human climate change, it's clear there are more named systems in the early season, and that would certainly often result in an earlier first name.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, is it due particularly to &lt;a href=&quot;http://www.usno.navy.mil/NOOC/nmfc-ph/RSS/jtwc/pubref/References/GUIDE/chap2/se302.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;sufficient ocean temperatures&lt;/a&gt; existing earlier in the season over wider areas?  It would seem odd that such a change would mostly impact only the number of tropical storms, and not change the number of hurricanes.  But further analysis should certainly be done and the other &lt;a href=&quot;http://wxmaps.org/pix/hurpot&quot; rel=&quot;nofollow noreferrer&quot;&gt;MPI factors&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do offer one final small postulate, based both upon these graphs and upon my own perceptions... perhaps at least a small part of the upswing in tropical storms might be due to an increase in the buzz at the start of each new year.  It seems there is more and more talk and &quot;excitement&quot; and interviews as each year get started.  And I wonder if that may prime forecasters to make earlier designations sometimes.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-05-27T05:36:51.823" LastActivityDate="2018-05-27T05:36:51.823" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="14282" PostTypeId="2" ParentId="13875" CreationDate="2018-05-26T13:55:18.477" Score="2" Body="&lt;p&gt;Yes, in your example, the group should have been omitted. From the &lt;a href=&quot;http://www.wmo.int/pages/prog/www/WMOCodes/WMO306_vI1/VolumeI.1.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;WMO Publication No. 306 - Manual On Codes - Volume I.1 - Part A&lt;/a&gt;, Section A, FM 12 SYNOP:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;12.2.7 &lt;em&gt;Group&lt;/em&gt; 8N&lt;sub&gt;h&lt;/sub&gt;C&lt;sub&gt;L&lt;/sub&gt;C&lt;sub&gt;M&lt;/sub&gt;C&lt;sub&gt;H&lt;/sub&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;12.2.7.1 This group shall be omitted in the following cases:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;(a) When there are no clouds (N = 0);&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;(b) When the sky is obscured by fog and/or other meteorological phenomena (N = 9);&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;(c) When the cloud cover is indiscernible for reasons other than (b) above, or observation is not made (N = /).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;metaf2xml tries to stick to the &lt;em&gt;Manual&lt;/em&gt; but tolerates deviations, so the group is recognized but marked as invalid.&lt;/p&gt;&#xA;" OwnerUserId="13048" LastEditorUserId="13048" LastEditDate="2018-05-27T06:10:53.163" LastActivityDate="2018-05-27T06:10:53.163" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14283" PostTypeId="1" CreationDate="2018-05-27T11:45:48.060" Score="4" ViewCount="107" Body="&lt;p&gt;When I use one DEM in my study area to delineate watersheds, the results are different from when I mosaic 4 DEM layers adjacent to each other. &#xA;After the mosaic process, 3 of the basins were merged in one large basin, and 2 other basins got larger extent.&lt;/p&gt;&#xA;" OwnerUserId="13051" LastActivityDate="2018-08-27T19:01:31.207" Title="how to know the correct results in watershed delineation in ArcGIS?" Tags="|hydrology|gis|watershed|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14285" PostTypeId="1" CreationDate="2018-05-27T23:03:55.147" Score="1" ViewCount="124" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/e7zTP.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vCK2K.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ptunr.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The stone has a raised texture on the top where the stripes are.&lt;br /&gt;&#xA;I'm not sure exactly where it was found.&lt;br /&gt;&#xA;It is not magnetic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/4K6NV.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9ZEXC.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="13055" LastEditorUserId="595" LastEditDate="2018-05-28T07:59:52.193" LastActivityDate="2018-05-28T07:59:52.193" Title="Can someone identify this 'striped' stone?" Tags="|geology|" AnswerCount="1" CommentCount="9" ClosedDate="2018-05-28T09:39:55.813" ContentLicense="CC BY-SA 4.0" />
  <row Id="14286" PostTypeId="2" ParentId="14285" CreationDate="2018-05-28T00:51:04.367" Score="0" Body="&lt;p&gt;Looks like a shell from a bivalve of some kind, that has been worn presumably by wave action.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You may want to update your question with more context. Where did you find it? Also, your photos are all out of focus and some are overexposed, so you may want to re-take the photos. You might also want to try asking on a biology or zoology site.&lt;/p&gt;&#xA;" OwnerUserId="63" LastActivityDate="2018-05-28T00:51:04.367" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14288" PostTypeId="1" CreationDate="2018-05-28T05:33:35.357" Score="4" ViewCount="80" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KFbrz.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KFbrz.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a plot of the vertical column densities of NO2 and O3 from an ultraviolet-visible spectrometer in Fairbanks, Alaska. It is interesting to see that when NO2 dips, O3 rises, and vice versa. Also, because the scale of both the graphs is so different, I cannot plot them together, which makes it difficult to see if the dips in both the plots is occurring simultaneously. This is important to verify the fact that is the instrument compromised by any kind of artefact or not. I was thinking of doing a dy/dx (where y=NO2 and x=O3) to see if the sign is the same, meaning that both the measurements are following the same pattern. Otherwise, the general trend of both the measurements is supposed to be opposite. Is this a good way to check my hypothesis?&lt;/p&gt;&#xA;" OwnerUserId="12661" LastEditorUserId="12661" LastEditDate="2018-05-28T09:47:50.750" LastActivityDate="2018-05-28T09:47:50.750" Title="Do NO2 and O3 titrate each other out in the atmosphere?" Tags="|meteorology|atmospheric-chemistry|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14289" PostTypeId="1" AcceptedAnswerId="14310" CreationDate="2018-05-28T08:59:36.813" Score="2" ViewCount="46" Body="&lt;p&gt;Obviously, there is going to be a large amount of variability, but what are some realistic values? &lt;/p&gt;&#xA;" OwnerUserId="11430" LastActivityDate="2018-05-30T17:31:34.670" Title="What's a reasonable flow rate/mass flux for a fumarole?" Tags="|geology|volcanology|petrology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14292" PostTypeId="1" CreationDate="2018-05-28T19:19:59.293" Score="4" ViewCount="157" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Posibly duplicate from&#xA;  &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13366/water-on-mars-and-earth&quot;&gt;Water on Mars and Earth&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I remember well a hydrology course where our teacher made some calculations of the total flux of water from Mantle ejections in Earth's history. He said the result gives you the total amount of water presently in the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then I started to hear theories about water coming from meteorites, and I wonder how much water has truly come from each source?&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2018-05-31T01:00:35.533" LastActivityDate="2018-10-03T23:00:18.303" Title="Ocean water coming from Mantle vs coming from meteorites" Tags="|geology|ocean|earth-history|meteorite|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14294" PostTypeId="1" AcceptedAnswerId="14295" CreationDate="2018-05-29T13:22:39.357" Score="1" ViewCount="253" Body="&lt;p&gt;Plants turn Carbon Dioxide into Oxygen, that is not a greenhouse gas. But Carbon Dioxide is. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, wouldn't plants cool the area?&lt;/p&gt;&#xA;" OwnerUserId="13062" LastEditorUserId="5594" LastEditDate="2018-05-29T13:50:46.413" LastActivityDate="2018-05-30T14:08:49.743" Title="If plants convert a greenhouse gas into a non-greenhouse gas, do they cool?" Tags="|climate-change|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14295" PostTypeId="2" ParentId="14294" CreationDate="2018-05-29T13:50:41.283" Score="1" Body="&lt;p&gt;Plants are natural machines that convert $CO_{2}$ into $O_{2}$ when there is sunlight. This process is known as photosynthesis because photons provide the energy that triggers the reaction,&#xA;$$6CO_{2} + 6H_{2}O -&amp;gt; C_{6}H_{12}O_{6} + 6O_{2}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question then is where do the plant products,such as leaves, fruits, flowers,roots that are composed of $C_{6}H_{12}O_{6}$  stored? If these plant remains are stored in the ground more than they are decomposed and then release $CO_{2}$ into the atmosphere, then we can positively say they are the natural cleaning robots, sorry super-robots or cleaning freaks!&lt;/p&gt;&#xA;" OwnerUserId="4877" LastActivityDate="2018-05-29T13:50:41.283" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14298" PostTypeId="2" ParentId="14292" CreationDate="2018-05-29T21:24:16.660" Score="1" Body="&lt;p&gt;The answer of this post clarifies also this related question: &#xA;&lt;strong&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/13366/water-on-mars-and-earth&quot;&gt;Water on Mars and Earth&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If water on Earth came from meteorites, why doesn't Mars have&#xA;  substantial water?&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;First off, that's a conjecture regarding the origin of the Earth's&#xA;  water rather than a known fact. A few times a year or so, a new&#xA;  journal article will appear that argues that the Earth's water is&#xA;  primordial, then another arguing that it came from comets, then yet&#xA;  another arguing that it came from asteroids.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;If the Earth's water is mostly primordial, most of it is over 4.5&#xA;  billion years old. If it came from asteroids or comets that collided&#xA;  with the Earth after the Earth had formed, it's still very, very old.&#xA;  Regardless of the source, almost all of the Earth's water has been&#xA;  here for at least 3.8 billion years old, since the end of the late&#xA;  heavy bombardment.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Mars and Earth are both rocky planets. If the water was there, at Mars or at the Earth on &lt;a href=&quot;http://www.deltawerken.com/The-Archaic/293.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Archaic&lt;/a&gt;, then I guess &lt;a href=&quot;https://www.earth.northwestern.edu/~amir/files/Role_of_Earth_s_Mantle_in_Water_and_Gases_in_the_Environment.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;degassing of Mantle&lt;/a&gt; was more quick than I thougth and what my hydrology teacher told us had not a lot of sense. &quot;Regardless of the source&quot;, so then water came from both sources but probably meteorites are not the main source. &lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2018-06-05T17:00:05.857" LastActivityDate="2018-06-05T17:00:05.857" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14300" PostTypeId="1" AcceptedAnswerId="14430" CreationDate="2018-05-30T04:27:43.750" Score="1" ViewCount="140" Body="&lt;p&gt;I am trying to study the impact of biogenic volatile organic compounds (BVOCs) on the atmospheric chemistry of the Arctic Region which has been said to be &quot;greening&quot;, by taking HCHO as a proxy. &lt;/p&gt;&#xA;" OwnerUserId="12661" LastEditorUserId="6465" LastEditDate="2018-06-15T17:44:50.383" LastActivityDate="2018-06-15T17:45:35.290" Title="Does &quot;Arctic Greening&quot; mean an increase in the spatial extent of vegetation, an increase in particular types of vegetation, or both?" Tags="|climate-change|atmospheric-chemistry|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14301" PostTypeId="1" AcceptedAnswerId="14303" CreationDate="2018-05-30T05:32:52.853" Score="1" ViewCount="161" Body="&lt;p&gt;Every storm season, supercells erupt in Montana and Wyoming. Wayward cold-core setups can trigger supercells or even long-tracked strong tornadoes in the Columbia/Willamette Valley and the rest of SW WA. Examples abound: 4/5/1972, 6/29/1989, 2/8/1993, 1/10/2008, 6/4/2009, &lt;a href=&quot;http://www.spc.noaa.gov/products/watch/2014/ww0459.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;8/12/2014&lt;/a&gt;, &lt;a href=&quot;http://komonews.com/weather/scotts-weather-blog/what-is-a-wet-microburst-the-cause-of-the-stormy-mayhem-in-thurston-county&quot; rel=&quot;nofollow noreferrer&quot;&gt;5/4/2017&lt;/a&gt;, the list goes on, and on, and on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I'm asking about severe weather in the region directly wedged in between the two aforementioned regions; all of WA east of the Cascades (East Slopes, Yakima Valley, Palouse, etc. This includes the southern Okanagan and the Kootenays in B.C.), and northern Idaho. Spokane/Coeur d'Alene, Pullman/Moscow, Lewiston, Wenatchee, Kelowna, Penticton, etc. Maybe even down to Boise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this an area that can have favorable conditions for rotating supercell storms (the kinds that can spawn significant tornadoes or drop monster hail), like in neighboring Montana, Wyoming, or the Deschutes Basin in central Oregon? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Such a region is on the leeside of the Cascades (which means capping inversions), and right in the firing line of monsoonal plumes from the Four Corners states, so to me it seems logical that (at least on paper) the northern reaches of the Inland Northwest can support supercellular development.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Addendum: I was asked to source my &quot;Deschutes gets monster hail and significant tornadoes&quot; statement. For hail: if you look at the &lt;a href=&quot;http://www.spc.noaa.gov/climo/reports/170504_rpts.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;SPC storm reports for May 4, 2017&lt;/a&gt;, you'll see that 1.75-2&quot; hail was recorded in Bend, as well as the towns of Sisters OR and Madras OR, around 10:30-11:00 p.m. PDT (0530-0600Z) on the 4th. For the Pacific Northwest excluding Idaho, I'd say those are some pretty darned big hailstones, and qualify as &quot;monster hail&quot; in a relative sense. Supercelluar thunderstorms are also not unheard of in this area, like the &lt;a href=&quot;https://www.weather.gov/media/wrh/online_publications/TAs/ta9601.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;July 9, 1995 supercell in Redmond OR.&lt;/a&gt; As for tornadoes, I was wrong. I checked the Tornado History Project map, and it looks like most tornadoes to hit the Beaver State are west of the Oregon Cascades.&lt;/p&gt;&#xA;" OwnerUserId="6816" LastEditorUserId="6816" LastEditDate="2018-05-31T09:05:35.700" LastActivityDate="2020-10-08T09:54:26.987" Title="Does the Columbia Basin, North Cascades and Idaho Panhandle/Clearwater get a lot of violent, rotating supercellular thunderstorms?" Tags="|meteorology|severe-weather|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14303" PostTypeId="2" ParentId="14301" CreationDate="2018-05-30T10:22:31.357" Score="4" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Note: These inputs are of a meteorologist who has quite actively tracked severe&#xA;weather around the US for a couple&#xA;decades... but also hadn't spent as much time in or attention on the west and northwest of the country.  So there could could theoretically be some degree of unintended bias.  I've tried to use objective data where possible, but it's something to keep in mind, regardless.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;In terms of &amp;quot;&lt;em&gt;a lot&lt;/em&gt;&amp;quot;, at least for tornadoes/hail, I'd suggest that nowhere west of the Rockies sees &lt;em&gt;a lot&lt;/em&gt; truly:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/icihBm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/icihBm.png&quot; alt=&quot;tornado tracks&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/kB1nym.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kB1nym.png&quot; alt=&quot;hail&quot; /&gt;&lt;/a&gt;&#xA;&lt;sub&gt;&lt;sup&gt;Tornadoes [left], hail [right]... source: &lt;a href=&quot;http://www.spc.noaa.gov/gis/svrgis/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Storm Prediction Center SVRGIS page&lt;/a&gt;&lt;/sup&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;I'd offer the idea that there of perhaps two notable reasons for that:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The &lt;strong&gt;lack of consistent and widespread surface wind fields favorable to tornadoes&lt;/strong&gt;... due to a combination of the lack of the big &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Lee_cyclogenesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;lee cyclogenesis&lt;/a&gt; seen east of the Rockies, along with the complex topography.&lt;/li&gt;&#xA;&lt;li&gt;The &lt;strong&gt;rarity of regular low-level moisture&lt;/strong&gt; significant enough to allow for low &lt;a href=&quot;https://www.youtube.com/watch?v=MbbjVUxtsDE&quot; rel=&quot;nofollow noreferrer&quot;&gt;LCLs&lt;/a&gt;.  The higher the storm base is above the ground, the less likely a tornado&lt;br /&gt;&#xA;[&lt;a href=&quot;http://www.spc.noaa.gov/publications/edwards/part2.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;in figure 6 of Edwards and Thompson 2000, all the red boxes showing tornadoes are on the left side, which are lower LCLs&lt;/a&gt;]&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;The lack of rich low-level moisture is due in large part to the lack of accessibility from warmer moisture sources, particularly the Gulf of Mexico; the Rockies provide a barrier to much of the moisture reaching further west.&lt;/p&gt;&#xA;&lt;p&gt;As you note, parts of Wyoming and Montana do see supercells and tornadoes a bit more often... but on a &lt;a href=&quot;http://en-us.topographic-map.com/places/United-States-2241/&quot; rel=&quot;nofollow noreferrer&quot;&gt;good topographic map&lt;/a&gt;, fair parts of those states are east of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Continental_Divide_of_the_Americas&quot; rel=&quot;nofollow noreferrer&quot;&gt;Continental Divide&lt;/a&gt;, and so still on an &amp;quot;&lt;a href=&quot;http://www.theweatherprediction.com/habyhints/112/&quot; rel=&quot;nofollow noreferrer&quot;&gt;upsloping&lt;/a&gt;&amp;quot; area and thereby not blocked by sinking regions which prevent full moisture progress.  They're still less-tornado prone due to elevation and increased distance from moisture, but it does happen.&lt;/p&gt;&#xA;&lt;p&gt;The desert southwest also does manage to get &lt;a href=&quot;https://en.wikipedia.org/wiki/North_American_Monsoon&quot; rel=&quot;nofollow noreferrer&quot;&gt;monsoon moisture sneaking around the terrain further south&lt;/a&gt;... but &lt;strong&gt;further north that monsoon moisture sees additional blocking by the more elevated terrain across Nevada and Utah&lt;/strong&gt;.  (And in the southwest, a different key ingredient in tornadic supercell development is typically missing in the summer monsoon: &lt;a href=&quot;https://en.wikipedia.org/wiki/North_American_Monsoon&quot; rel=&quot;nofollow noreferrer&quot;&gt;upper-air winds sufficient for supercell development&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;The Pacific Coast does see a few occasional tornadoes.  But from what I've seen, they typically form from smaller storms with much less classical and intense mesocyclones.  As you mention, they're a bit more in line with cold-core setups, which usually produce weaker short-lived tornadoes than classic supercells of the Plains and on east.  If you plug in the events you speak of into &lt;a href=&quot;http://www.spc.noaa.gov/exper/archive/events/&quot; rel=&quot;nofollow noreferrer&quot;&gt;SPCs Severe Weather Events archive&lt;/a&gt;, [pick the date, then click Obs and Mesoanalysis on the left, then use the dropdowns to find various parameters]&#xA;you can see that CAPE was typically very meager (well short of 1000 J/kg) and the storm structure quite weak in reflectivity in comparison to a classic supercell, more indicative of such cold-core setups.&lt;/p&gt;&#xA;&lt;p&gt;Capping inversions may be helpful to &amp;quot;keep the lid on the pot&amp;quot; if you have strong CAPE (and therefore quality moisture) and intense updrafts to erode the cap during the day.  But as it is, &lt;strong&gt;there isn't enough moisture typically for the cap to be a positive factor&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Quite a bit of the area you mentioned, such as Spokane, makes up one of the &lt;a href=&quot;https://en.wikipedia.org/wiki/United_States_rainfall_climatology#/media/File:Average_precipitation_in_the_lower_48_states_of_the_USA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;more arid regions of the country&lt;/a&gt;.  Further removed from the rain shadow of the Cascades, the Idaho Panhandle does get more precipitation, but it's mostly in &lt;a href=&quot;https://www.bestplaces.net/climate/city/idaho/lewiston&quot; rel=&quot;nofollow noreferrer&quot;&gt;cooler months&lt;/a&gt; that lack the deep convective development needed for supercells, probably because of the &lt;a href=&quot;https://climate.ncsu.edu/edu/HighLow&quot; rel=&quot;nofollow noreferrer&quot;&gt;proximity of the Pacific high&lt;/a&gt; in summer months.  Further east in E ID/W MT, particularly in the Flathead Valley, there are &lt;a href=&quot;https://www.e-education.psu.edu/meteo3/sites/www.e-education.psu.edu.meteo3/files/images/lesson8/tstrm_climo.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;occasional summer thunderstorms&lt;/a&gt;... but the storms may well be higher based due to the limited low-level moisture, and so have low potential of tornadic development.  For more on the climate complexities at play in the Idaho vicinity, &lt;a href=&quot;https://wrcc.dri.edu/narratives/IDAHO.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;check out this article&lt;/a&gt; from the Western Regional Climate Center.&lt;/p&gt;&#xA;&lt;p&gt;In the end, the area you ask about is one of the weakest regions for supercell development in the entire United States.  The entire quarter of the country west of the Rockies isn't much better.  &lt;a href=&quot;https://mesonet.agron.iastate.edu/plotting/auto/?q=92&quot; rel=&quot;nofollow noreferrer&quot;&gt;This page&lt;/a&gt; from Iowa State University will create an image showing the number of days since each pocket of the country (sorted by National Weather Service forecast office areas) last saw a tornado warning.  It shows that the Idaho Panhandle hasn't seen a tornado warning in over 10 years:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cQ3a6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cQ3a6.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;More than anywhere but northern California.&lt;/p&gt;&#xA;&lt;p&gt;And another ISU &lt;a href=&quot;https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&amp;amp;q=90&amp;amp;t=cwa&amp;amp;v=yearavg&amp;amp;ilabel=yes&amp;amp;geo=polygon&amp;amp;drawc=yes&amp;amp;year=1989&amp;amp;year2=2019&amp;amp;sdate=1989%2F01%2F01%200000&amp;amp;edate=2019%2F12%2F31%202359&amp;amp;station=OTX&amp;amp;state=IA&amp;amp;phenomena=SV&amp;amp;significance=W&amp;amp;cmap=jet&amp;amp;interval=1&amp;amp;dpi=100&amp;amp;_fmt=png&quot; rel=&quot;nofollow noreferrer&quot;&gt;page&lt;/a&gt; allows it to be shown that:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/vlpdn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vlpdn.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;... Most spots in northern Idaho only see about one severe thunderstorm warning per year on average (versus &lt;a href=&quot;https://i.stack.imgur.com/X8L0n.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;10-20 per year over Oklahoma&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;So the danger of severe convective weather is remarkably low in that region of the country overall.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2020-10-08T09:54:26.987" LastActivityDate="2020-10-08T09:54:26.987" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14304" PostTypeId="1" AcceptedAnswerId="14305" CreationDate="2018-05-30T10:41:17.667" Score="1" ViewCount="60" Body="&lt;p&gt;I am trying to find out monthly average temperature and average rainfall for states of USA from 2015 to 2017. To my surprise I am not able to find it anywhere.  Please help. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I could find &lt;a href=&quot;https://www.usclimatedata.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this link&lt;/a&gt; - which provides data in a format I want. However, they took average of 30 years, 1981 to 2010. I need data for individual months, starting from Jan 2015 to Dec 2017 (36 data points).&lt;/p&gt;&#xA;" OwnerUserId="5880" LastActivityDate="2018-05-30T12:13:11.420" Title="monthly temperatue by state" Tags="|climate|temperature|precipitation|rainfall|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14305" PostTypeId="2" ParentId="14304" CreationDate="2018-05-30T12:13:11.420" Score="4" Body="&lt;p&gt;It may take a few minutes of work this way...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But did find digging through &lt;a href=&quot;https://www.ncdc.noaa.gov/cdo-web/datasets&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCDC's climate data inventory&lt;/a&gt;, the &lt;a href=&quot;https://www.ncdc.noaa.gov/temp-and-precip/climatological-rankings/&quot; rel=&quot;nofollow noreferrer&quot;&gt;climatological rankings pages&lt;/a&gt; should help find what you're looking for if you're looking for their full state averages.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I think can help you a step further with addresses to go through: if you replace STATENUMBER in the address of:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Temperature: &lt;a href=&quot;https://www.ncdc.noaa.gov/cag/statewide/time-series/STATENUMBER/tavg/1/4/1895-2018?base_prd=true&amp;amp;begbaseyear=1901&amp;amp;endbaseyear=2000&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncdc.noaa.gov/cag/statewide/time-series/STATENUMBER/tavg/1/4/1895-2018?base_prd=true&amp;amp;begbaseyear=1901&amp;amp;endbaseyear=2000&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Instead with each of the numbers 1 through 48, you can get the state data for each of the US contiguous states.  And Alaska is 50.  Likewise with precip:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Precipitation: &lt;a href=&quot;https://www.ncdc.noaa.gov/cag/statewide/time-series/STATENUMBER/pcp/1/4/1895-2018?base_prd=true&amp;amp;firstbaseyear=1901&amp;amp;lastbaseyear=2000&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncdc.noaa.gov/cag/statewide/time-series/STATENUMBER/pcp/1/4/1895-2018?base_prd=true&amp;amp;firstbaseyear=1901&amp;amp;lastbaseyear=2000&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, it looks like disappointingly Hawaii (and territories) doesn't get the same data produced, or at least available anywhere I can find on that site.  If you really want to seek that out, you might consider using Honolulu and Juan &lt;a href=&quot;http://sercc.com/nowdata.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;climate reports&lt;/a&gt; for a reasonable proxy, or the answer to the question &lt;a href=&quot;https://gis.stackexchange.com/questions/195244/current-global-climate-dataset&quot;&gt;Current Global Climate Dataset?&lt;/a&gt; on GSE may offer a rough avenue towards fair gridded information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not the easiest avenue, would love to see something better (and hopeful if you do go through this tedious method, perhaps post it to a Github repo or such so that more data may be easily available in the future to others facing the same problem.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2018-05-30T12:13:11.420" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="14306" PostTypeId="1" CreationDate="2018-05-30T13:19:37.193" Score="6" ViewCount="457" Body="&lt;p&gt;I have soil moisture data from Regional Climate Models expressed in $kg/m^2$. Τhis quantity is the total soil moisture that is estimated for the land column. The depth of this column is dependent on the land surface model that was used.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How could I transform soil moisture units expressed in $kg/m^2$ to $m^3/m^3$ so that model outputs are comparable to remote sensing soil moisture data that are expressed in $m^3/m^3$? Is there a way of doing this transformation without taking into consideration the soil depth?&lt;/p&gt;&#xA;" OwnerUserId="13063" LastEditorUserId="106" LastEditDate="2018-09-03T16:14:55.877" LastActivityDate="2024-01-31T07:51:41.270" Title="Transformation of soil moisture units" Tags="|soil-moisture|" AnswerCount="4" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14308" PostTypeId="2" ParentId="14294" CreationDate="2018-05-30T14:08:49.743" Score="1" Body="&lt;p&gt;Plants do cool the area around them but it is not due to gas exchange, (not directly) plants provide shade and loss water during gas exchange this loss creates evaporative cooling. oxygen and carbon dioxide diffuse too quickly to much effect on the local environment where they are produced by themselves. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2018-05-30T14:08:49.743" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14310" PostTypeId="2" ParentId="14289" CreationDate="2018-05-30T17:31:34.670" Score="1" Body="&lt;p&gt;Surprisingly enough most of the figures I could find were actually about thermal output but back working the figures, and assuming I read the formulas properly (not guaranteed I'm afraid) it looks like 5-7 litres per second is the ballpark average gas flow based on fifty years worth of data from several fumarole fields in the central North Island of New Zealand. I have no idea how representative that figure would be of fields elsewhere.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-05-30T17:31:34.670" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14311" PostTypeId="2" ParentId="14306" CreationDate="2018-05-30T17:34:34.000" Score="0" Body="&lt;p&gt;Not one that I can immediately see, in order to derive a per cubic metre figure (m&lt;sup&gt;3&lt;/sup&gt;) you need to know how many cubes of soil you have in a given column unit, that requires the depth of the unit in question.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="725" LastEditDate="2018-07-30T23:33:15.497" LastActivityDate="2018-07-30T23:33:15.497" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14313" PostTypeId="1" CreationDate="2018-05-31T04:28:22.620" Score="1" ViewCount="17" Body="&lt;p&gt;I am looking for papers on the stratigraphy, geochronology and/or compositional make up of the Wastach Range and its formations. I prefer a broad overview paper and I can't seem to find one. Any help is appreciated.&lt;/p&gt;&#xA;" OwnerUserId="13073" LastEditorUserId="6298" LastEditDate="2018-05-31T07:39:16.700" LastActivityDate="2018-05-31T07:39:16.700" Title="Where can I find papers on the geology of the Wastach Range in Utah" Tags="|sedimentology|metamorphism|literature-request|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14314" PostTypeId="2" ParentId="14313" CreationDate="2018-05-31T07:36:16.877" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://pubs.er.usgs.gov/publication/cir296&quot; rel=&quot;nofollow noreferrer&quot;&gt;This report&lt;/a&gt; on the stratigraphy is probably a good place to start.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additonally, searching Google Scholar for Wasatch Range geochronology brings up a number of papers on the geochronology of specific formations if you are interested in that.&lt;/p&gt;&#xA;" OwnerUserId="2570" LastActivityDate="2018-05-31T07:36:16.877" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14315" PostTypeId="1" CreationDate="2018-05-31T08:25:51.020" Score="1" ViewCount="137" Body="&lt;p&gt;&lt;strong&gt;Context:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For one of my reports I have taken samples of a rock from an adjacent creek. I have done XRD analysis to get compositions of calcium, potassium and aluminium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;My question:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know about ternary diagrams, this is the base graphical method I will be using. However, what other &lt;em&gt;basic&lt;/em&gt; methods could I employ to emphasize the effects of weathering in this experiment? The following data is what I plan on using. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lRKPO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lRKPO.png&quot; alt=&quot;Data&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13075" LastEditorUserId="725" LastEditDate="2018-06-01T11:08:04.227" LastActivityDate="2018-06-01T11:08:04.227" Title="What other graphical methods can be used to represent weathering?" Tags="|geology|geochemistry|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14318" PostTypeId="1" AcceptedAnswerId="14428" CreationDate="2018-05-31T16:10:17.667" Score="0" ViewCount="84" Body="&lt;p&gt;It's a generic question but was wondering if there is a threshold level of soil water beyond which planting a crop (for e.g. soybean) can be hindered because the soil is too wet or flooded. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a background, for a given location, I have the soil water content coming out of a water balance model. In a real world, how much excess soil water compared to field capacity would ideally prevent planting of crops.The reason I am asking is because I am making a model on planting days where a day is classified as 'no planting' given excess water in the soil. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please advise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Adding to this, my water model generates soil water content and surface runoff as well&lt;/p&gt;&#xA;" OwnerUserId="13078" LastEditorUserId="13078" LastEditDate="2018-05-31T16:43:01.863" LastActivityDate="2018-06-14T17:53:11.027" Title="How much excess water prevents planting of a crop" Tags="|soil|agriculture|soil-moisture|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14322" PostTypeId="1" CreationDate="2018-06-01T08:34:30.220" Score="2" ViewCount="68" Body="&lt;p&gt;I know it's a silly question, but it really bothers me since the word hemisphere derives from Greek ημί- (i.e. hemi-) which cannot be further expanded, while the English equivalent semi- can be further expanded to quarter-.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, my question has three parts:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Firstly, does the choice of &quot;hemi-&quot; instead of &quot;semi-&quot; only from geology or is it used as such in mathematics in the same manner?&lt;/li&gt;&#xA;&lt;li&gt;If the Earth were instead flat, would we refer to a hemicircle or semicircle?&lt;/li&gt;&#xA;&lt;li&gt;If I want to refer to the northwestern part of Earth, what's the correct word, since hemisphere is obviously wrong?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Thank you in advance&lt;/p&gt;&#xA;" OwnerUserId="13085" LastEditorUserId="6298" LastEditDate="2018-06-01T14:50:38.160" LastActivityDate="2018-06-01T21:31:15.003" Title="Are there other divisions of Earth following beyond hemispheres?" Tags="|terminology|earth-system|" AnswerCount="1" CommentCount="4" ClosedDate="2018-06-01T23:59:04.070" ContentLicense="CC BY-SA 4.0" />
  <row Id="14323" PostTypeId="2" ParentId="14315" CreationDate="2018-06-01T11:07:54.403" Score="1" Body="&lt;p&gt;First of all, you probably used XRF, and not XRD. XRF is a method used to obtain chemical compositions. XRD is used to obtain crystal structures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A ternary diagram would be indeed very useful in this case. Another thing you might want to try is ratios: a plot of Al vs. K/Ca or something similar. Potassium and calcium likely behave differently in different weathering regimes, so it could be useful to show it.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-06-01T11:07:54.403" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14325" PostTypeId="1" CreationDate="2018-06-01T18:51:54.067" Score="3" ViewCount="176" Body="&lt;p&gt;How many miles (or how many hours/days) does air have to travel over the ocean to reach maximum humidity or carry the maximum amount of water it would hold at typical humidity assuming a wind speed of roughly 10 miles per hour?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand the typical humidity to be roughly 80% over the oceans. I have a fantasy world with its own landmasses and I'm trying to be able to figure out the climate based on temperature, wind direction and rainfall at different latitudes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take North Africa versus the same Latitude in China. At 30 degrees latitude you don't always get a desert climate. If the wind can travel over water it will bring in some rainfall but I'm trying to understand how much depending on the answer to the above question.&lt;/p&gt;&#xA;" OwnerUserId="13088" LastActivityDate="2018-06-04T17:57:28.373" Title="Ocean air reaching maximum humidity" Tags="|meteorology|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="14326" PostTypeId="1" CreationDate="2018-06-01T20:14:44.277" Score="2" ViewCount="67" Body="&lt;p&gt;In a question related to my previous one. I am in the process of building a fantasy world. I have the landmasses with elevation worked out along with the air/wind directions at the various latitudes and the temperature both average and seasonal. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I am missing in determining the climates is the rainfall. I have a rough idea of probable rainfall as humid air goes inland based on elevation changes and temperature. However, if someone could provide a more exact formula or answer to exactly how much average (daily or monthly or whatever) rainfall should occur assuming the air mass hits the land carrying a certain amount of grams of water per cubic meter. For example at 20 deg centigrade air can hole 17.3 grams per cubic meter at 100% humidity. I may be incorrectly assuming rainfall will be largely based on how much altitude the air has to climb as it moves inland.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second to that is what rate does the air mass gain humidity as it travels over water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Imagine I have a air mass moving over ocean then over land and then perhaps back over another stretch of water before hitting land again. Those are the type of issues I am facing in trying to determine the climate&lt;/p&gt;&#xA;" OwnerUserId="13088" LastEditorUserId="10681" LastEditDate="2018-08-29T02:39:40.520" LastActivityDate="2018-08-29T02:39:40.520" Title="Estimating Average Rainfall" Tags="|meteorology|rainfall|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14327" PostTypeId="2" ParentId="14322" CreationDate="2018-06-01T21:31:15.003" Score="2" Body="&lt;p&gt;Not, IMO an ES question, but depending on what level of division, and if you are talking about the surface only or a partition of the sphere extending to the core, terms such as spherical sector, spherical cap, and quadrant would be fairly common descriptive terms for parts of a sphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cap would be the portion of the sphere cut by a plain passing though the sphere.  The Hemispheres are caps cut by the plane passing through either the equator or the poles.  Normally a cap would describe an area formed by cutting the plane parallel to the equator, as in the lines of latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A sector would be a cone centered and the center of the sphere and extended to the surface.  Think of a cone capped by a cap as described above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A quadrant would typically be a wedge, think of an orange wedge, or a part of one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do not think any of there really are especially common to use in relationship to Earth though they are valid descriptors.  Lines of longitude and latitude are the common differentiation that describe these divisions, and phrases such as above/below the 45th parallel to describe the halves of the Northern Hemisphere.  &lt;/p&gt;&#xA;" OwnerUserId="6178" LastActivityDate="2018-06-01T21:31:15.003" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14330" PostTypeId="2" ParentId="14326" CreationDate="2018-06-02T07:14:28.683" Score="1" Body="&lt;p&gt;Probable rainfall is constrained by several factors, both spatial and temporal. Rainfall modelling is in itself a humongous topic. You may refer to this &lt;a href=&quot;https://www.staff.ncl.ac.uk/h.j.fowler/weathersim.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt; for having a good idea of the simulation process &amp;amp; maybe adapt some of the basic equations for a rough estimate by assuming some parameters as minimally affecting your site.&lt;/p&gt;&#xA;" OwnerUserId="11360" LastActivityDate="2018-06-02T07:14:28.683" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14334" PostTypeId="1" CreationDate="2018-06-02T13:05:33.013" Score="0" ViewCount="320" Body="&lt;p&gt;I have been flying to different countries so often and this question came to my mind out of nowhere! Which are the two countries with the flight time between them and time zone differences are equal?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, considering current time differences between time zones on all over the world, let's say that hypothetical i will take off at 16:00 from Istanbul and i will land to Munich. And time difference between these cities is 2 hours and flight duration is 2 hours. So, when i will land, the local time in Munich will be 16:00.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question basically is that is there any countries/cities in the world like the example above?&lt;/p&gt;&#xA;" OwnerUserId="13093" LastActivityDate="2018-06-02T16:24:50.790" Title="which are the two countries with the flight time between them and time zone differences are equal" Tags="|geography|time|" AnswerCount="2" CommentCount="4" ClosedDate="2018-06-04T11:47:53.890" ContentLicense="CC BY-SA 4.0" />
  <row Id="14336" PostTypeId="2" ParentId="14334" CreationDate="2018-06-02T14:36:36.000" Score="1" Body="&lt;p&gt;If you flew from Warsaw, Poland to Lviv, Ukraine the &lt;a href=&quot;https://www.google.com/search?client=firefox-b&amp;amp;ei=laoSW8whhtXQBIGbgfAK&amp;amp;q=flight%20time%20from%20warsaw%20to%20lviv&amp;amp;oq=flying%20time%20from%20warsaw%20to%20lv&amp;amp;gs_l=psy-ab.1.0.33i22i29i30k1.26401.28732.0.31520.6.6.0.0.0.0.508.977.2-2j5-1.3.0....0...1c.1.64.psy-ab..3.3.976...0i22i30k1.0.15IDNccrTac&quot; rel=&quot;nofollow noreferrer&quot;&gt;flight time&lt;/a&gt; would be one hour and the &lt;a href=&quot;http://dateandtime.info/timedifference.php?id1=703448&amp;amp;id2=756135&quot; rel=&quot;nofollow noreferrer&quot;&gt;time difference&lt;/a&gt; the two is one hour.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-06-02T14:36:36.000" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14337" PostTypeId="2" ParentId="14334" CreationDate="2018-06-02T16:24:50.790" Score="2" Body="&lt;p&gt;I'm not going to look for examples, but there will be some. More interesting is to consider the underlying geometry:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At one extreme, if you fly from north to south (or vice versa) you'll experience little or no change in time zone no matter how long you fly for.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the other extreme, if you fly from east to west the time zones will go in the &lt;em&gt;wrong&lt;/em&gt; direction. Depending on how you define the question there might be an &quot;answer&quot; in this direction, where you fly west for n hours and go back by n time zones. But for the rest of this question, let's assume you want &lt;em&gt;later&lt;/em&gt; time zones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you fly from west to east, you're chasing the time zones in the right direction... but unless you have a supersonic aircraft, you can't go fast enough - you will travel east slower than the rate at which the earth is spinning, so (as long as you go far enough for more than a 1 time zone change, i.e. to get out of rounding errors) the number of hours you fly for will always be more than the number of time zones you gain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to match the two, you must fly diagonally : north-east or south-east. The exact angle will depend on the speed of your plane and the latitude that you start from. And then, you have to find a city along that line!&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2018-06-02T16:24:50.790" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14341" PostTypeId="2" ParentId="13054" CreationDate="2018-06-03T13:56:31.363" Score="0" Body="&lt;p&gt;There is ice below this melted section which shows the &quot;heat&quot; source is not from a water table or the ground beneath the water. It is obviously radiant heat from the sun.  As can be seen on a super hot sidewalk, radiant heat can greatly exceed the temperature of the air. The location of the melting would predominantly be related to the areas that get the most sun but could also be related to thickness of ice beneath which could be related to many factors with the lake. &lt;/p&gt;&#xA;" OwnerUserId="13097" LastActivityDate="2018-06-03T13:56:31.363" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14342" PostTypeId="1" AcceptedAnswerId="19903" CreationDate="2018-06-04T04:09:32.447" Score="4" ViewCount="384" Body="&lt;p&gt;What is the point called when water can not rise above or visually seem to have a ceiling in the atmosphere? What makes that point ideal?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FoRpo.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FoRpo.jpg&quot; alt=&quot;https://www.space.com/35357-nasa-noaa-2016-climate-report-press-conference-webcast.html&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastActivityDate="2020-07-03T18:38:43.923" Title="Why do clouds have ceilings and bases?" Tags="|meteorology|geophysics|thunderstorm|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14343" PostTypeId="1" CreationDate="2018-06-04T09:24:44.827" Score="5" ViewCount="243" Body="&lt;p&gt;I recently interpreted some XRF data on samples of a granodiorite which were classified under three different types of physical characteristics: very little, mild and significant levels of weathering. I plotted ratios between $Al_2O_3$ for $CaO$ and $K_2O$ and noticed $CaO$ had a much lower correlation coefficient, i.e., it was more clumped. I know it's about which of these elements go into clay compounds but I need a bit more help understanding. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Data&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lfH1a.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lfH1a.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13075" LastEditorUserId="13075" LastEditDate="2018-06-04T11:32:37.643" LastActivityDate="2020-08-22T17:04:05.347" Title="Why would CaO be more finely spread than K2O in Granodiorite?" Tags="|geology|rocks|mineralogy|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="14344" PostTypeId="2" ParentId="14343" CreationDate="2018-06-04T13:00:23.727" Score="1" Body="&lt;p&gt;I would suggest that there is a combination of effects here: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Potassium(K) compounds are usually more soluble than their Calcium(Ca) equivalents, and often at much lower temperatures. For example $CaCO_3$ is in considered insoluble in even boiling water, while $K_2CO_3$ is fully soluble at room temperature. Potassium can therefore migrate more easily during weathering involving water infiltration than can Calcium leading to a finer distribution. The &quot;clumps&quot; of $CaO$ represent more closely it's original crystal positions while the finely divided $K_2O$ has migrated farther dispersing it through the samples.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The clumping in less weathered samples could be purely an artifact of the nature of the parent rock &lt;a href=&quot;https://en.wikipedia.org/wiki/Granodiorite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Granodiorite&lt;/a&gt; is relatively enriched in Calcium over Potassium so Calcium shows up as large concentrations while Potassium is more thinly spread through the samples.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-06-04T13:00:23.727" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14345" PostTypeId="2" ParentId="14342" CreationDate="2018-06-04T13:59:16.667" Score="3" Body="&lt;p&gt;Clouds have ceilings and bases because the atmosphere is stratified. &#xA;Atmosphere is stratified due to earth's rotation and variance of composition, humidity, density,  temperature, and pressure from surface of the earth to the edge of the orbital space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clouds form under specific conditions of composition, humidity, density,  temperature, and pressure.  These conditions are often persisted within specific layers in the atmosphere.  Complex fluid flow of air is also a contributing factor for layering within the atmosphere between air masses for varying density.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer is probably best summed up as the result of the physics of fluid dynamics.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2018-06-04T13:59:16.667" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14346" PostTypeId="1" CreationDate="2018-06-04T16:28:47.900" Score="3" ViewCount="204" Body="&lt;p&gt;More specifically, I'm trying to work out climate analogues for my farm. It's at 5200-6200ft in South India. My area is a bit too small for the Köppen Map to correctly reveal patterns.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll be getting a weather station etc. soon, but it'll take a few months to a year before I have enough data to work with. But right now I have some experimental planting to do, so.. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is, if you were at around 5800ft in a tropical/subtropical region of India, would the climate then be more like a temperate zone or an alpine climate, but with monsoons?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To put it another way, my question has a general aspect to it too, which is: what happens to a tropical zone as the land increases in elevation? Does it become more &quot;temperate&quot; or &quot;alpine&quot; for all practical purposes? And what &quot;tropical&quot; factors remain in effect (for example, sunlight, I'm guessing)? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I sound confused about how this stuff works, I would love if someone could direct me to a guide of some kind too!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further information: It's in the Nilgiri Hills, Tamil Nadu, in a region called Bengal Mattam. There's a small stream that runs through the farm, right at the border, all along the lowest point of our farm/the hillside. The stream then turns sharply and in one kilometer from that turning point, empties into an irregularly shaped reservoir, which is about 669 meters from one end to other, and about 250 on two other extremes. I'm guessing that won't count for much except increase humidity and dew?&lt;/p&gt;&#xA;" OwnerUserId="13104" LastEditorUserId="6465" LastEditDate="2018-09-05T14:14:53.527" LastActivityDate="2020-10-20T00:10:45.020" Title="What kind of climate could you expect in a mountainous area in a subtropical region?" Tags="|meteorology|climate|measurements|agriculture|" AnswerCount="2" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="14347" PostTypeId="2" ParentId="14346" CreationDate="2018-06-04T16:38:30.530" Score="1" Body="&lt;p&gt;Do any of the resources &lt;a href=&quot;https://data.gov.in/keywords/annual-rainfall&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; help you with historical rainfall trends for your area? Those are probably going to be a better guide than any approximation based on your latitude, altitude, and terrain as to what you can grow. I say this because at 5800ft the mountains are going to control your weather way more than a lot of other factors that are important at sea level.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-06-04T16:38:30.530" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14348" PostTypeId="1" CreationDate="2018-06-02T21:06:25.007" Score="5" ViewCount="59" Body="&lt;p&gt;I've read not long ago that the absorption line of the &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; becomes larger with temperature thanks to Doppler effect (if it's false it would be great to tell me). My question is the following: Does this imply, like I think, that more energy is &quot;stored&quot; on Earth (thanks to greenhouse effect) and so play a role in climate change? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the answer is yes, how big is this role? &lt;/p&gt;&#xA;" OwnerUserId="13970" OwnerDisplayName="thephysics17" LastEditorUserId="11908" LastEditDate="2019-03-03T03:20:08.150" LastActivityDate="2019-03-03T03:20:08.150" Title="Does the extension of the absorption line of $\text{CO}_2$ with temperature play a role in the climate change?" Tags="|geophysics|climate-change|temperature|co2|greenhouse-gases|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14349" PostTypeId="2" ParentId="14325" CreationDate="2018-06-04T17:57:28.373" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://www.engineeringtoolbox.com/evaporation-water-surface-d_690.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.engineeringtoolbox.com/evaporation-water-surface-d_690.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The amount of evaporated water can be expressed as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;gs = Θ A (xs - x) / 3600                                 (1)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;or&lt;/p&gt;&#xA;&#xA;&lt;p&gt;gh = Θ A (xs - x)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where&lt;/p&gt;&#xA;&#xA;&lt;p&gt;gs = amount of evaporated water per second (kg/s)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;gh = amount of evaporated water per hour (kg/h)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Θ = (25 + 19 v) = evaporation coefficient (kg/m2h)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;v = velocity of air above the water surface (m/s)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A = water surface area (m2)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;xs = maximum humidity ratio of saturated air at the same temperature as the water surface (kg/kg)  (kg H2O in kg Dry Air)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;x = humidity ratio air (kg/kg) (kg H2O in kg Dry Air)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note! The units for Θ don't match since the this is an empirical equation - a result of experience and experiments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Found the answer to my question.&lt;/p&gt;&#xA;" OwnerUserId="13088" LastActivityDate="2018-06-04T17:57:28.373" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14354" PostTypeId="1" AcceptedAnswerId="14357" CreationDate="2018-06-04T21:15:59.720" Score="7" ViewCount="1080" Body="&lt;p&gt;The extent of my understanding of limestone is about what Wikipedia says at the very top of the page:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Limestone is a sedimentary rock, composed mainly of skeletal fragments of marine organisms such as coral, forams and molluscs. Its major materials are the minerals calcite and aragonite, which are different crystal forms of calcium carbonate (CaCO3).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What catches my curiosity is the word &quot;mainly&quot; there... I can't tell if it means &quot;the main part of &lt;em&gt;all&lt;/em&gt; limestone&quot; is [skeletal fragments of organisms]&quot; or if it means &quot;part of limestone (in the usual cases) is [skeletal fragments of organisms]&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Phrased in the most general and interesting way (to me):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given an Earth-like planet with all the right ingredients (e.g. large bodies of liquid water, iron-nickel partially-liquid core, etc.) with one exception&amp;mdash;no history of carbon-based life forms&amp;mdash;would we find significant amounts of limestone like we have on Earth today?&lt;/p&gt;&#xA;" OwnerUserId="421" LastActivityDate="2018-06-06T00:46:35.250" Title="In an Earth-like planet with no history of carbon-based life forms, would there be limestone?" Tags="|geology|planetary-science|sedimentology|petrology|carbon|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14357" PostTypeId="2" ParentId="14354" CreationDate="2018-06-05T00:55:53.357" Score="5" Body="&lt;p&gt;I'd have to say, yes. Once life evolved in the world's oceans, the vast majority of limestone formation has been through the organic process. However, before life did evolve, limestone formed through an inorganic process where rain water falling through a CO&lt;sub&gt;2&lt;/sub&gt;-rich atmosphere reacted to form a weak carbonic acid solution that then reacted with calcium-containing minerals to form calcites. This then washed into the world's oceans to form limestone deposits.&lt;br&gt;&lt;br&gt;From &lt;a href=&quot;http://hyperphysics.phy-astr.gsu.edu/hbase/Geophys/limestone.html&quot; rel=&quot;noreferrer&quot;&gt;gsu.edu&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Limestone may form inorganically or by biochemical processes.&lt;br&gt;&lt;br&gt;&#xA;  Another form of limestone of inorganic origin is oolitic limestone, limestone formed from small spherical grains called ooids.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In an paper from &lt;a href=&quot;https://news.stanford.edu/news/2004/june2/lowegeo-62.html&quot; rel=&quot;noreferrer&quot;&gt;Stanford.edu&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Carbonic acid dissociated to form hydrogen ions, which found their way into the structures of weathering minerals, and bicarbonate, which was carried down rivers and streams to be deposited as limestone and other minerals in ocean sediments.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So even in a world devoid of carbon-based life, limestone could still form if it had a CO&lt;sub&gt;2&lt;/sub&gt;-rich atmosphere, water (and thus rain), and calcium-containing crustal deposits. Though the paper from Stanford is theoretical, note that this does not mean hypothetical and is (I believe) based on solid science.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2018-06-05T00:55:53.357" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14358" PostTypeId="2" ParentId="14354" CreationDate="2018-06-05T07:17:36.937" Score="1" Body="&lt;p&gt;The sedimentary register shows on Earth firsts significant amounts of limestones came from &lt;a href=&quot;https://en.wikipedia.org/wiki/Stromatolite&quot; rel=&quot;nofollow noreferrer&quot;&gt;stromatolites&lt;/a&gt; and foraminifera at the end of &lt;a href=&quot;https://en.wikipedia.org/wiki/Precambrian&quot; rel=&quot;nofollow noreferrer&quot;&gt;Precambrian&lt;/a&gt;.&#xA;After life explosion, two main carbonated deposits are registered:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;- Powerful basin deposits at the coast with &lt;a href=&quot;https://en.wikipedia.org/wiki/Coral_reef&quot; rel=&quot;nofollow noreferrer&quot;&gt;coral reefs&lt;/a&gt;.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;- Big benthic deposits with &lt;a href=&quot;https://en.wikipedia.org/wiki/Foraminifera&quot; rel=&quot;nofollow noreferrer&quot;&gt;foraminifera&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Coccolithophore&quot; rel=&quot;nofollow noreferrer&quot;&gt;coccolithophoridae&lt;/a&gt; at seabed&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A limestone uses to be those skeletal fragments, that are cemented by CaCo3 at diagenesis, but not always. At calm environments, mudstone can be formed, primarily from algae. Another exception to this are &lt;a href=&quot;https://en.wikipedia.org/wiki/Dunham_classification&quot; rel=&quot;nofollow noreferrer&quot;&gt;crystalline limestones&lt;/a&gt; that have changed their texture at &lt;a href=&quot;https://en.wikipedia.org/wiki/Diagenesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;diagenesis&lt;/a&gt; and skelets are not recognizable, but that doesn't mean origin of CaCo3 wasn't organic. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5AMaN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5AMaN.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Dunham classification of carbonates&lt;/strong&gt;. Image from: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:The_Rebooted_Dunham_Classification.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;commons.wikimedia.org&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is another exception, as noticed: &lt;a href=&quot;https://en.wikipedia.org/wiki/Oolite&quot; rel=&quot;nofollow noreferrer&quot;&gt;oolites&lt;/a&gt;. Oolites are inorganical concretions around a bioclast or clast. What I have read is this structures are formed at the beaches thanks too to algaes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyhow, a non-life rocky planet can produce carbonates at his first magmatic phases. The rock is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonatite&quot; rel=&quot;nofollow noreferrer&quot;&gt;carbonatite&lt;/a&gt;, wich is a magmatic rock, not a sedimentary limestone. You could then have some scattered sedimentary deposits where &lt;a href=&quot;https://en.wikipedia.org/wiki/Cementation_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;cement&lt;/a&gt; is CaCo3. I find it unlikely, but erosion of carbonatites could lead to true limestones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are too terrestrial limestones formed on lakes and rivers called &lt;a href=&quot;https://en.wikipedia.org/wiki/Tufa&quot; rel=&quot;nofollow noreferrer&quot;&gt;tufa&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Recently it has been demonstrated that microbially induced&#xA;  precipitation may be more important than physico-chemical&#xA;  precipitation. Pedley et al. (2009) showed with flume experiments&#xA;  that precipitation does not occur unless a biofilm is present, despite&#xA;  supersaturation.&quot;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Tufa&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia (see quoted paper)&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonates_on_Mars&quot; rel=&quot;nofollow noreferrer&quot;&gt;There is no evidence of such deposits on Mars neither&lt;/a&gt;. Carbonates are found , but being magnesite (MgCo3) the main carbonate with little percentages of calcite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, I can be wrong, but my answer to &quot;significant amounts&quot; is no, knowing little deposits of CaCO3 could thermodinamicaly been formed on a non-life rocky planet.&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2018-06-05T11:06:38.847" LastActivityDate="2018-06-05T11:06:38.847" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14359" PostTypeId="1" AcceptedAnswerId="14360" CreationDate="2018-06-05T09:47:07.133" Score="3" ViewCount="3348" Body="&lt;p&gt;I am reading the paper &lt;a href=&quot;https://www.dropbox.com/s/mc8lipg08uxgzez/Characterization%20of%20yield%20reduction%20in%20Ethiopia%20using%20a%20GIS%20based%20crop%20water%20balance%20model.pdf?dl=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Characterization of yield reduction in Ethiopia using a GIS-based crop water balance model&lt;/a&gt; by Gabriel B. Senay and James Verdin, and it says on page 3:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Soil water content (SW) is estimated through a simple mass&#xA;  balance equation where the total volume is defined by the water&#xA;  holding capacity (WHC) of the soil. SW is the amount of soil&#xA;  water present at a given time step. The value of SW varies from&#xA;  a minimum of 0 to a maximum equal to WHC (in mm)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What is the WHC here? Is it the &lt;em&gt;Field capacity&lt;/em&gt; or &lt;em&gt;Field Capacity - Wilting Point&lt;/em&gt;?&lt;/p&gt;&#xA;" OwnerUserId="13078" LastEditorUserId="595" LastEditDate="2018-06-05T20:16:20.390" LastActivityDate="2018-06-05T20:16:20.390" Title="What is the difference between Water Holding Capacity, Field Capacity and TAWC?" Tags="|soil|soil-moisture|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14360" PostTypeId="2" ParentId="14359" CreationDate="2018-06-05T16:56:39.653" Score="3" Body="&lt;p&gt;Okay Water Holding Capacity(WHC) is how much water the soil has in it at total saturation, if you filled every soil pore space completely with water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Field Capacity(FC), if I remember correctly from first year, is shorthand for the water that stays in the soil after surface runoff and groundflow has ceased; the sub-saturation &quot;ground state&quot; of the moist soil if you will.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Soil Water(SW) would appear based on the excerpt provided to be referring to the percentage of WHC present at time of measurement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You've also asked about Total Available Water Capacity(TAWC) which is the water that can be accessed by plants, this is the water stored in macro, as opposed to micro, pores in the soil (it's more complex than that but we always worked it as a two grade problem; pores big enough for plant roots and pores too small for them). Usually to quantify this figure WHC, or FC depending on what's of interest, is multipled by the percentage of plant accessible pore spaces in the soil, this gives the volume of water plants can access before they start to wilt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please note I'm mostly working from my memory of an entry level class I took nearly a decade ago so this may not be perfect, but it it does check against the research material I quickly skimmed while writing.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-06-05T16:56:39.653" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14361" PostTypeId="1" AcceptedAnswerId="14363" CreationDate="2018-06-06T00:18:44.627" Score="9" ViewCount="1887" Body="&lt;p&gt;An oxidizer, fuel, and heat are needed for a fire.  When considering oxygen as the oxidizer, an oxygen concentration of approximately 16% is required for combustion.  Plant material is the fuel considered when thinking of a wildfire.  A couple examples of natural heat sources could be lightning or lava.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the diagram below, plants as a fuel source would not be available until at least 1 billion years ago.  Atmospheric oxygen concentrations of at least 16% did not occur until approximately 500 million years ago.  Therefore, I would guess that there is no evidence of wildfires until within the last 500 million years.  What I'm wondering is &lt;strong&gt;what is the earliest known evidence of wildfires?&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/T80zS.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/T80zS.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Oxygen_atmosphere.png&quot; rel=&quot;noreferrer&quot;&gt;Oxygen Atmosphere&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastEditorDisplayName="user11318" LastEditDate="2018-06-06T00:50:20.440" LastActivityDate="2020-09-25T06:36:04.690" Title="When did wildfires start to occur on earth?" Tags="|earth-history|oxygen|fire|plant|wildfire|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14362" PostTypeId="2" ParentId="14354" CreationDate="2018-06-06T00:46:35.250" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;In an Earth-like planet with no history of carbon-based life forms, would there be limestone?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Short answer: &lt;strong&gt;Maybe&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The form of carbon in limestone is oxidised carbon: carbonate: CO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;2-&lt;/sup&gt;. This is different from organic carbon, which is mostly composed of carbon-hydrogen (&quot;hydrocarbons&quot;) molecules and compounds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Limestone is a sedimentary rock composed mostly of calcite or aragonite - calcium carbonate. As you mentioned - that calcium carbonate is coming from the shells of dead marine animals. I would note that if you have a planet with carbon-based lifeforms, but they do not form shells from calcium carbonate so this process of limestone formation would not exist.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Limestones can also form chemically. There is calcium carbonate dissolved in oceans and lakes. If you evaporate and dry them, that calcium carbonate will precipitate. The solubility of calcium carbonate depends on pH. If those water bodies become less acidic (rising pH), you will precipitate chemical deposits of calcium carbonate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You know that white scale in your tea kettle? This is calcium carbonate. Limestone. So this can form without any life, just by changing the temperature of the water, this changing the solubility of the calcium carbonate. Examples of chemically precipitated &quot;limestones&quot; are &lt;a href=&quot;https://en.wikipedia.org/wiki/Tufa&quot; rel=&quot;nofollow noreferrer&quot;&gt;tufa&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Travertine&quot; rel=&quot;nofollow noreferrer&quot;&gt;travertine&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we venture out of the &quot;sedimentary limestones&quot;, there are also carbonatites, which are igneous rocks crystallised out of a carbonate rich magma. These are rare on Earth (we know of only &lt;a href=&quot;https://en.wikipedia.org/wiki/Ol_Doinyo_Lengai&quot; rel=&quot;nofollow noreferrer&quot;&gt;one volcano&lt;/a&gt; that erupts this stuff), but could be more common on other planets. Weathering of these rocks can produce proper sedimentary limestones.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-06-06T00:46:35.250" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14363" PostTypeId="2" ParentId="14361" CreationDate="2018-06-06T03:29:15.677" Score="19" Body="&lt;p&gt;A definitive statement comes from the abstract of Scott and Glasspool&lt;sup&gt;1&lt;/sup&gt;, 2006:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Charcoal, a proxy for fire, occurs in the fossil record from the Late &lt;a href=&quot;https://en.wikipedia.org/wiki/Silurian&quot; rel=&quot;nofollow noreferrer&quot;&gt;Silurian&lt;/a&gt; (≈420 Myr) to the present.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;One of the tired old truisms you learn is that fire needs three things: Oxygen, fuel, and a source of ignition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is little doubt that there has been lightning since Earth's formation. (&lt;a href=&quot;https://en.m.wikipedia.org/wiki/Paleolightning&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia:Paleolightning&lt;/a&gt;). There appears to be &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0166263508702408&quot; rel=&quot;nofollow noreferrer&quot;&gt;evidence&lt;/a&gt; of the fossil &lt;a href=&quot;https://en.wikipedia.org/wiki/Fulgurite&quot; rel=&quot;nofollow noreferrer&quot;&gt;fulgurite&lt;/a&gt; from the Proterozoic Eon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oxygen levels were probably sufficient around 470 Myr. (&lt;a href=&quot;https://en.wikipedia.org/wiki/Fossil_record_of_fire&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia:Fossil record of fire&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So as soon as plant-based fuel appears on land, there is evidence of fire. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although there is evidence for &lt;a href=&quot;https://en.wikipedia.org/wiki/Embryophyte&quot; rel=&quot;nofollow noreferrer&quot;&gt;land plant&lt;/a&gt;s for as far back as 850 Myr, and some evidence for land-based bryophyta (moss) appears in the &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Ordovician&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ordovician&lt;/a&gt; Period, evidence of widespread plant colonization of the land, and plants with vascular tissue that can dry out into fuel, do not appear until the Silurian period with the appearance of &lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Cooksonia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cooksonia&lt;/a&gt;&lt;/em&gt; and other early tracheophytes. (&lt;a href=&quot;https://en.wikipedia.org/wiki/Evolutionary_history_of_plants&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia: Evolutionary history of plants&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The level of oxygen in the atmosphere does appear to play a role, as there is a gap in the Mid-Devonian period, apparently coincident with a dip in oxygen levels (to about 13%), but there doesn't appear to be a consensus on that. At any rate, fossil charcoal picks up again in the late Devonian as oxygen levels rise again. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt; Andrew C. Scott and Ian J. Glasspool, The diversification of Paleozoic fire systems and fluctuations in atmospheric oxygen concentration,Proc Natl Acad Sci U S A. 2006 Jul 18;103(29):10861-5. Epub 2006 Jul 10.&#xA;(Abstract at &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1544139/#!po=0.694444&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1544139/#!po=0.694444&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2018-06-06T20:38:57.637" LastActivityDate="2018-06-06T20:38:57.637" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14364" PostTypeId="1" AcceptedAnswerId="14365" CreationDate="2018-06-06T09:22:20.653" Score="2" ViewCount="83" Body="&lt;p&gt;I started studying the effects of weathering on granodiorite (see previous posts) and plan on referencing the link between the chemical weathering of feldspar plagioclase leading to kaolinization, a process I am relatively unfamiliar with. In brief terms, how would this reaction reduce the porosity of the rock? Also, how would the release of $Ca$ and $K$ influence further degradation of the rocks porosity? &lt;/p&gt;&#xA;" OwnerUserId="13075" LastEditorUserId="13075" LastEditDate="2018-06-06T09:28:13.167" LastActivityDate="2018-06-06T17:55:39.887" Title="How does the synthesis of Kaolinite (and it's by products) influence porosity in granodiorite?" Tags="|geology|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="14365" PostTypeId="2" ParentId="14364" CreationDate="2018-06-06T17:42:25.330" Score="2" Body="&lt;p&gt;Kaolinite &quot;grains&quot;, for want of any better term, are swollen with chemically bonded water compared to the crystals they weather out of so porosity is decreased by particle expansion while at the same time overall density drops. Kaolin also has very strong particle-particle adhesion so any mechanical deformation of the material tends to compress it leading to further reductions in bulk porosity. The influence of Calcium and Potassium on the ongoing weathering of the rock and it's overall porosity depends greatly on the weathering regime; for example if weathering is continuously under wet conditions then Calcium and Potassium will be mobilised in ground water and removed. On the other hand in a wetting-drying cycle Calcium and Potassium liberated from the parent rock become oxides when the material dries out, those subsequently react strongly with water in the next wetting cycle acidifying the environment and accelerating rock decomposition.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="10735" LastEditDate="2018-06-06T17:55:39.887" LastActivityDate="2018-06-06T17:55:39.887" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14367" PostTypeId="1" CreationDate="2018-06-06T23:04:43.200" Score="5" ViewCount="921" Body="&lt;p&gt;I came across a question asking what's the number of tectonic plates in this illustration:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/1BbCa.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1BbCa.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know on which basis we count the tectonic plates.&#xA;And I'm confused because I think they are 5 but the answer is 3.&#xA;As the illustration shows that there are a mid oceanic ridge which is formed because of a divergent plate motion between two oceanic plates and an oceanic trench which is formed due to covergent plate motion between two oceanic plates, so I think that there are three oceanic plates plus two continental plates which are at the two edges of the illustration. Am I right?&lt;/p&gt;&#xA;" OwnerUserId="13117" LastEditorUserId="725" LastEditDate="2018-06-07T09:14:16.347" LastActivityDate="2019-07-24T20:02:08.427" Title="Number of tectonic plates" Tags="|plate-tectonics|homework|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14368" PostTypeId="2" ParentId="14367" CreationDate="2018-06-07T03:10:27.270" Score="7" Body="&lt;p&gt;This is primarily an exercise in interpreting a minimalist diagram. Believe me, you will &lt;em&gt;have&lt;/em&gt; to learn to read even sketchier diagrams. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, the test had the correct answer to the question. Unambiguously, there are only &lt;strong&gt;&lt;em&gt;three&lt;/em&gt;&lt;/strong&gt; plates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The left and right plates each contain a piece of continental crust and a piece of oceanic crust connected by a &lt;a href=&quot;https://en.wikipedia.org/wiki/Passive_margin&quot; rel=&quot;nofollow noreferrer&quot;&gt;passive continental margin&lt;/a&gt;. In each case, the oceanic &lt;a href=&quot;https://en.wikipedia.org/wiki/Terrane&quot; rel=&quot;nofollow noreferrer&quot;&gt;terrane&lt;/a&gt; and the continental terrane move as a unit, so there's only one plate on the left and only one on the right. With the middle, oceanic-only plate, that makes three.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although the diagram you gave us is a little more simplified than I'm comfortable with, you can tell that whoever drew the diagram meant for the left and right plates to contain passive margins. The elliptical loops of arrows are intended to be interpreted as &lt;a href=&quot;https://en.wikipedia.org/wiki/Mantle_convection&quot; rel=&quot;nofollow noreferrer&quot;&gt;convection cells in the mantle&lt;/a&gt;, and each cell drags the lithosphere above as a unit. So, anything above any one convection cell should be interpreted as one plate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a slightly more detailed diagram showing a passive margin:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/4/45/Passive_Contiental_Margin.jpg&quot; alt=&quot;passive continental margin&quot;&gt;&#xA;&lt;em&gt;(Source: Wikipedia, CC 3.0)&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2019-07-24T20:02:08.427" LastActivityDate="2019-07-24T20:02:08.427" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14369" PostTypeId="1" AcceptedAnswerId="22896" CreationDate="2018-06-07T04:38:12.953" Score="9" ViewCount="376" Body="&lt;p&gt;I was recently reading Zach Holman's &lt;a href=&quot;https://zachholman.com/talk/utc-is-enough-for-everyone-right&quot; rel=&quot;noreferrer&quot;&gt;blogpost on time&lt;/a&gt; and remembering that I've had to work with CMIP5 output that used a 360 day calendar, rather than a 365 day or a Greogrian (or Proleptic Gregorian) one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do models that store output in this calendar run on a more physically accurate timestep and then somehow interpolate to a different calendar, or are they actually simulating on a 360 calendar? If they're actually using a 360 calendar, how does that work? Is incoming solar radiation simply parameterised in an interpolated way across the year for 360 days of regular duration? I can't imagine that the days are stretched out to account for being 1.5% fewer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does any of this have a substantial impact on the results?&lt;/p&gt;&#xA;" OwnerUserId="66" LastActivityDate="2021-10-27T14:07:15.890" Title="Do 360 day calendars affect climate models?" Tags="|climate|models|climate-models|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14370" PostTypeId="1" CreationDate="2018-06-07T04:49:35.657" Score="1" ViewCount="401" Body="&lt;p&gt;I am a novice here and I really appreciate the graph of magnitude &gt;7 earthquakes related to 11(22)yr solar minimum cycles.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was wondering what the correlation would be (if any) if we changed the window to  consider 7.5 and above quakes over the past 400 years  (assuming such data is available and reliable)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, some discussion about the difference between Solar Minimums and Grand Solar Minimums would be helpful.  In other words are there set periods in which Solar Minimums are even smaller than usual (Grand Solar Minimums) and do really large earthquakes tend to happen during these periods? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you for your interest.  &lt;/p&gt;&#xA;" OwnerUserId="13118" LastActivityDate="2018-12-15T02:41:33.617" Title="What would a graph of magnitude &gt;7.5 earthquakes over last 400 years compared to Grand Solar Minimums look like?" Tags="|earthquakes|solar-terrestrial-physics|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14371" PostTypeId="2" ParentId="14367" CreationDate="2018-06-07T09:14:06.157" Score="5" Body="&lt;p&gt;There are three plates, because there are two plate boundaries (marked in blue): a convergent margin to the left, and a divergent margin to the right.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lithospheric &lt;em&gt;plate&lt;/em&gt; #2 contains only oceanic &lt;em&gt;crust&lt;/em&gt;. Lithospheric plates #1 and #3 contain both continental and oceanic &lt;em&gt;crusts&lt;/em&gt;. Note the difference between the terms &lt;em&gt;plate&lt;/em&gt; and &lt;em&gt;crust&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The place where continental and oceanic crusts meet within a single lithospheric plate is called a passive margin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It may have been a lithospheric plate margin in the past, but now it is a fossil margin and is not active.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/uk5b1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uk5b1.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="6465" LastEditDate="2018-06-07T15:38:04.903" LastActivityDate="2018-06-07T15:38:04.903" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14372" PostTypeId="1" AcceptedAnswerId="14373" CreationDate="2018-06-07T11:31:55.120" Score="4" ViewCount="270" Body="&lt;p&gt;Where can I find a list of all earthquakes that happened on Earth since 1900?&lt;br /&gt;I need time, longitude/latitude, and power -- preferably in .csv format.&lt;/p&gt;&#xA;" OwnerUserId="13121" LastEditorUserId="595" LastEditDate="2018-06-07T15:16:34.997" LastActivityDate="2018-06-07T15:16:34.997" Title="Catalog of all significant earthquakes since 1900?" Tags="|earthquakes|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14373" PostTypeId="2" ParentId="14372" CreationDate="2018-06-07T14:27:01.480" Score="6" Body="&lt;p&gt;Okay so I got the data from&#xA;&lt;a href=&quot;https://earthquake.usgs.gov&quot; rel=&quot;noreferrer&quot;&gt;https://earthquake.usgs.gov&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the website only allows to get 20k records at a time I made a little python script that downloads data for each month.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;import os&#xA;import requests&#xA;&#xA;for x in range(1900,2016):&#xA;    for y in range(1,13):&#xA;        url='https://earthquake.usgs.gov/fdsnws/event/1/query.csv?starttime='+str(x)+'-'+str(y)+'-31%2023:59:59&amp;amp;endtime='+str(x)+'-'+ str(y+1) +'-31%2023:59:59&amp;amp;minmagnitude=2.5&amp;amp;orderby=time'&#xA;        print(url)&#xA;        response = requests.get(url)&#xA;        with open(os.path.join(&quot;C:/Users/kristjag/OneDrive/delo/potresi&quot;, &quot;potresi_&quot;+str(x)+&quot;_&quot;+str(y)+&quot;.csv&quot;), 'wb') as f:&#xA;            f.write(response.content)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Code above take some time to finish but when completed you get earthquake data for every month from 1900-2016 &lt;/p&gt;&#xA;" OwnerUserId="13121" LastActivityDate="2018-06-07T14:27:01.480" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14374" PostTypeId="1" CreationDate="2018-06-07T19:53:16.400" Score="5" ViewCount="2232" Body="&lt;p&gt;I just saw an image of a gecko stuck in amber 58 million years ago.  Why don't animals rot when they are trapped in amber?  I've seen dry insects whose chitin shells persist for a long time away from water and scavengers, but things with skin rot and dramatically change in appearance in the outside world.&lt;/p&gt;&#xA;" OwnerUserId="13123" LastActivityDate="2018-06-08T12:30:06.017" Title="Why don't animals rot when trapped in amber?" Tags="|fossils|amber|" AnswerCount="1" CommentCount="5" ClosedDate="2018-06-15T12:42:22.337" ContentLicense="CC BY-SA 4.0" />
  <row Id="14375" PostTypeId="2" ParentId="10090" CreationDate="2018-06-08T10:22:21.023" Score="1" Body="&lt;p&gt;Most atmospheric science researchers use back-trajectory analysis in qualitative sense to explain source of a pollutant. And as pointed out by the questioner, it is not possible to associate trajectories calculated at a particular time to the measurement that is average of say several hours. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, quantitative analysis of observed concentration with back-trajectories is possible and is used to identify emission sources and their strength. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the quantitative analysis, a large number of back-trajectories are simulated (of the order of 100000) from the place of measurement, however each trajectory is initiated with slightly different initial condition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let me explain with an example. Suppose PM2.5 concentration was measured on a certain date as 24 hour average at location given by co-ordinates x, y and z. Assuming that air was well mix in region surrounding x, y and z given by x-dx to x + dx, y-dy to y+dy and z-dy to z + dy, backtrajectories will be simulated, each with slight different x,y and z but within volume given by 2dx*2dy*2dz. Also, the number of trajectories simulated will be equally distributed in the volume and time period (24 hours in this example) to which observation represents. The simulation will result in distribution of trajectory with some grid-boxes visited by several trajectories whereas others may have no trajectory or very few trajectories. Emissions in the grid-boxes which are more frequently visited, have more potential to contribute to observed concentration. In other words, the concentration being measured at x, y, z will be proportional to sum of amount of time spent by each trajectories multiplied by emission flux in that grid box. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;More detailed description of backtrajectory analysis and its application to related to observed quantity are available in following articles. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Gadhavi et al., 2015, Evaluation of black carbon inventories using a Lagrangian dispersion model - a case study over Southern India, Atmos Chem Phys, vol. 15, 1447-1461, doi: &lt;a href=&quot;http://dx.doi.org/10.5194/acp-15-1447-2015&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.5194/acp-15-1447-2015&lt;/a&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Seibert and Frank, 2004, Source-receptor matrix calculation with a Lagragian particle dispersion model in backward mode, Atmos. Chem. Phys., vol. 4, 51-63, doi:&lt;a href=&quot;http://dx.doi.org/10.5194/acp-4-51-2004&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.5194/acp-4-51-2004&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="10780" LastEditorUserId="10780" LastEditDate="2018-09-12T09:08:13.520" LastActivityDate="2018-09-12T09:08:13.520" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14376" PostTypeId="2" ParentId="14374" CreationDate="2018-06-08T12:30:06.017" Score="5" Body="&lt;p&gt;things need to be exposed to bacteria to rot, amber produces a perfect form fitting seal and has several &lt;a href=&quot;https://www.tandfonline.com/doi/abs/10.1080/01629778500000141?journalCode=rbal20&quot; rel=&quot;noreferrer&quot;&gt;antimicrobial&lt;/a&gt; properties to boot killing off bacteria that is already present. Even microbes trapped in amber become preserved. This makes a lot of sense when you realize the resin evolved to seal injuries in trees if it did not prevent the spread of bacteria it would not work. HOwever preservation in amber is &lt;a href=&quot;https://europepmc.org/backend/ptpmcrender.fcgi?accid=PMC1689027&amp;amp;blobtype=pdf&quot; rel=&quot;noreferrer&quot;&gt;not perfect&lt;/a&gt; and the things do degrade, but do so so slowly that more geologically recently deposits have decayed so little is is almost undetectable, the type of resin also matters all resin is not equal and &lt;a href=&quot;http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0195482&quot; rel=&quot;noreferrer&quot;&gt;some amber resins preserves better than others&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2018-06-08T12:30:06.017" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14377" PostTypeId="2" ParentId="2482" CreationDate="2018-06-08T13:52:37.380" Score="-1" Body="&lt;p&gt;The way to go is bung them in the microwave or oven. But then your oven will smell like cigarette smoke etc. Best in the sunligh/ patio where the odours can dissipate in open air. Nothing to do with witchcraft. It is simply an absorbent volcanic rock, much like a dense pumice.&lt;/p&gt;&#xA;" OwnerUserId="13125" LastActivityDate="2018-06-08T13:52:37.380" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14378" PostTypeId="1" CreationDate="2018-06-08T15:22:05.623" Score="0" ViewCount="38" Body="&lt;p&gt;I am looking for a website that can I look for to check and see the precipitation totals for past days.. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I go to this site : &lt;a href=&quot;https://www.cocorahs.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.cocorahs.org/&lt;/a&gt; . It lacks in some areas where I live in the rural areas...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there sites that can I find that are hard to find areas like where I live ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Location is Pueblo West, Colorado. There are some areas that received totals in Pueblo.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have gone to The Weather Channel , WU, etc...but no luck. &lt;/p&gt;&#xA;" OwnerUserId="5771" LastEditorUserId="5771" LastEditDate="2018-06-08T23:53:53.530" LastActivityDate="2018-06-09T17:27:02.953" Title="Precipitation Totals past days online?" Tags="|meteorology|precipitation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14379" PostTypeId="1" AcceptedAnswerId="14383" CreationDate="2018-06-08T16:39:42.480" Score="1" ViewCount="68" Body="&lt;p&gt;Hi guys I have an small question here. At the NDBC website they have at most of the buoys the steepness of the sea at that time and date: &lt;a href=&quot;http://www.ndbc.noaa.gov/station_page.php?station=46012&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.ndbc.noaa.gov/station_page.php?station=46012&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However this stations collect all the wave spectrum data and direction of it, so I suppose they use the cut frequency and then from then they decide how step is the sea at that moment at that place. At other places they don't get all the data, being more specific on the device: &lt;a href=&quot;http://www.ndbc.noaa.gov/station_page.php?station=46214&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.ndbc.noaa.gov/station_page.php?station=46214&lt;/a&gt; they only have the dominant wave period and the wave height at the files: &lt;a href=&quot;http://www.ndbc.noaa.gov/station_history.php?station=46214&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.ndbc.noaa.gov/station_history.php?station=46214&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data in the file looks like this:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;#YY  MM DD hh mm WDIR WSPD GST  WVHT   DPD   APD MWD   PRES  ATMP  WTMP  DEWP  VIS  TIDE&#xA;#yr  mo dy hr mn degT m/s  m/s     m   sec   sec degT   hPa  degC  degC  degC   mi    ft&#xA;2017 01 01 00 22 999 99.0 99.0  3.40 12.50  9.60 311 9999.0 999.0  12.2 999.0 99.0 99.00&#xA;2017 01 01 00 52 999 99.0 99.0  3.30 11.76  9.48 322 9999.0 999.0  12.2 999.0 99.0 99.00&#xA;2017 01 01 01 22 999 99.0 99.0  3.18 11.11  9.24 329 9999.0 999.0  12.2 999.0 99.0 99.00&#xA;2017 01 01 01 52 999 99.0 99.0  3.29 11.11  9.54 314 9999.0 999.0  12.1 999.0 99.0 99.00&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Then using only that data how I can obtain the sea steepness?. &lt;/p&gt;&#xA;" OwnerUserId="13126" LastActivityDate="2018-06-09T02:00:23.840" Title="How the stepness can be computed at NDBC from site with only dominant wave data and windwave data" Tags="|ocean|waves|open-data|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14380" PostTypeId="1" CreationDate="2018-06-08T19:24:40.073" Score="1" ViewCount="143" Body="&lt;p&gt;What will be the effect on a desert-like area if it is covered with millions of umbrella-like structures like the following one?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IfkG6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IfkG6.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would it play any positive role in reversing the desertification?&lt;/p&gt;&#xA;" OwnerDisplayName="user12774" LastActivityDate="2018-06-14T13:25:32.623" Title="Reversing the desertification" Tags="|desert|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14381" PostTypeId="1" CreationDate="2018-06-08T21:28:35.300" Score="0" ViewCount="41" Body="&lt;p&gt;Assuming precession occurs on a 26000 year period, will we eventually have to change time zones (forward or backward) to adjust for this? The way I see it, in continuous time, we will eventually be at a different point on the axis, thus having less or more sun during a day. Am I missing something?&lt;/p&gt;&#xA;" OwnerUserId="13129" LastActivityDate="2018-06-09T19:36:36.393" Title="Precession &amp; Time" Tags="|time|astronomy|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14383" PostTypeId="2" ParentId="14379" CreationDate="2018-06-09T02:00:23.840" Score="0" Body="&lt;p&gt;The methodology to calculate wave steepness used by &lt;a href=&quot;http://www.ndbc.noaa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NDBC&lt;/a&gt; is explained in: &lt;a href=&quot;http://www.ndbc.noaa.gov/algor.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.ndbc.noaa.gov/algor.shtml&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Steepness is defined as&#xA;$\xi=\frac{2\pi H_s}{gT_z^2}$ where $H_s$ is the significant wave height and $T_z$ is the average wave period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From your dataset, you have significant wave height and average wave period so you should be fine.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2018-06-09T02:00:23.840" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14384" PostTypeId="1" CreationDate="2018-06-09T16:41:34.290" Score="3" ViewCount="67" Body="&lt;p&gt;In the &lt;a href=&quot;https://en.wikipedia.org/wiki/Martin_Ledge&quot; rel=&quot;nofollow noreferrer&quot;&gt;current Wikipedia article for Martin Ledge&lt;/a&gt; it reads: &quot;Martin Ledge is small barren rocks that barely stick out of the waters&quot;. However, the NOAA chart for the area shows a low tide depth of 16 feet, which indicates that the rocks do not uncover. Which is right, the wikipedia article or the chart?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oqyuc.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oqyuc.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2018-06-09T16:41:34.290" Title="Does Martin Ledge uncover?" Tags="|ocean|mapping|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14385" PostTypeId="2" ParentId="14378" CreationDate="2018-06-09T17:27:02.953" Score="3" Body="&lt;p&gt;One of the best sites I know of for this type of analysis is the National Weather Service’s &lt;a href=&quot;https://water.weather.gov/precip&quot; rel=&quot;nofollow noreferrer&quot;&gt;precipitation analysis site&lt;/a&gt;, which combines radar data, gauge observations, and satellite data to make an informed analysis over the entire country, not just where there are rain gauges.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can use the controls below the map to choose day(s) for which you’d like to see the precipitation analysis, and it looks like they have archived data going back to 2005. I don’t know offhand if you can quickly get exact totals from the site, but it should be enough for a rough idea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And if you’re more specifically interested in snow totals (instead of liquid precipitation), there’s also &lt;a href=&quot;https://www.nohrsc.noaa.gov/nsa/&quot; rel=&quot;nofollow noreferrer&quot;&gt;another site&lt;/a&gt; from the NWS dedicated to snowfall analyses.&lt;/p&gt;&#xA;" OwnerUserId="7137" LastActivityDate="2018-06-09T17:27:02.953" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14386" PostTypeId="2" ParentId="14381" CreationDate="2018-06-09T19:36:36.393" Score="2" Body="&lt;p&gt;I believe the source of your confusion is that you are confusing a sidereal year with a tropical year. The sidereal year, which is the definition most often cited as the standard definition of a year, is not the year our calendars use. That year is the tropical year. The sidereal year is the time it takes for the Earth to complete one orbit around the sun (sounds familiar, right?). The tropical year, the one we actually use to keep time, is the time it takes for the Sun to complete its apparent journey from one polarly extreme to the next (e.g. summer solstice to summer solstice). The two differ by about 20 minutes. In about 13,000 years the constellations we see in the nighttime sky in June will be the ones we see in the nighttime sky in December, but the sun will still be above you (more or less) at noon on that day.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2018-06-09T19:36:36.393" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14390" PostTypeId="2" ParentId="14380" CreationDate="2018-06-10T06:13:51.290" Score="1" Body="&lt;p&gt;It would depend on the reflectivity of the material used - a lighter color will reflect more solar radiation and help cool an area fairly quickly , but it would take longer for the area covered with such structures to experience changes in  poleward. energy transport. The poleward heat transport determines where the jet streams are located and how far north and south tropical rains (intertropical convergence zone) move. Thus, whilst the structures would cool the area, there would likely be insufficient rainfall to re-establish substantial plant life and reverse desertification. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short, because of the need for water and the mesoscale weather patterns in a desert, shading the deserts would have little effect on the rate of desertification. &lt;/p&gt;&#xA;" OwnerUserId="13135" LastActivityDate="2018-06-10T06:13:51.290" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14391" PostTypeId="2" ParentId="14202" CreationDate="2018-06-10T06:53:28.793" Score="0" Body="&lt;p&gt;The height at which clouds form is called the cloud condensation level (CCL), where air lifted by convection powered by temperature differences cools and condensates. When it comes to basic physics, yes, evaporation would need to be less (i.e. zero) for condensation to occur. &#xA;However, this is not necessarily the correct way to look at it, as relative humidity is the determining factor for cloud formation. Relative humidity depends on temperature and pressure. &#xA;As a volume of unsaturated air cools, its relative humidity increases. If sufficiently cooled, the relative humidity becomes 100%, the temperature equals the dew point, and clouds form. So it's less to do with evaporation and condensation than the amount of humidity, and the temperature (and temp gradient) and pressure of an air mass. &lt;/p&gt;&#xA;" OwnerUserId="13135" LastActivityDate="2018-06-10T06:53:28.793" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14392" PostTypeId="1" AcceptedAnswerId="14433" CreationDate="2018-06-10T09:07:13.967" Score="0" ViewCount="68" Body="&lt;p&gt;I'm looking to extrapolate rising temperatures based on the increasing CO2 levels. From this article: &lt;a href=&quot;https://greenphysicist2.blogspot.com/2010/02/atmospheric-carbon-dioxide-levels.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;CO2 in 2050&lt;/a&gt;, with the following formula used to extrapolate the CO2 levels:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;$CO_2\ level = 280 \cdot \left( 1+\exp(0.0222\cdot \left(year-2052\right)) \right)$. This formula gives the projected CO2 level in parts per million (ppm) for any year from 1958 on, assuming the growth rate is constant at 2.22%. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This seems fair since CO2 increases by 2.2% per year and it's effects are exponential.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to roughly use the same formula to extrapolate future temperatures based on this same CO2 increase as the accompanying document suggests: &lt;a href=&quot;http://greenphysicist2.blogspot.com/2010/02/increase-in-global-temperature.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Temps using CO2&lt;/a&gt;. The issue is the constants used... because if the same formula is used, then at year 2052, the temperature would be doubled which is obviously not realistic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my question is: what coefficients should be used in this: $T=\left(1+\exp(ct)\right)$ formula, where $c$ is a constant ($0.0222$ I would think) and $t$ being a some measure of time.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or is there a better formula to use which correlates exponentially increasing CO2 with increasing temperatures?&lt;/p&gt;&#xA;" OwnerUserId="13136" LastEditorUserId="5594" LastEditDate="2018-06-11T05:45:15.953" LastActivityDate="2018-06-15T23:31:49.507" Title="Formula for rising temperatures" Tags="|temperature|co2|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14397" PostTypeId="1" AcceptedAnswerId="14401" CreationDate="2018-06-11T02:30:07.803" Score="7" ViewCount="30625" Body="&lt;p&gt;Spring water comes out colder from being underground. But if you get deeper the temperature goes up. At what depth does the underground stop getting colder and begins getting warmer? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a map for that point like a geothermal table map? I ask this because I want to build a underground water cooling air conditioner in the same manner that pipes are heated on roof tops.&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="595" LastEditDate="2018-06-11T10:12:59.723" LastActivityDate="2024-01-21T21:28:42.110" Title="At what depth does the underground begin to warm up?" Tags="|geology|geothermal-heat|mapping|natural-conditions|underground-water|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14399" PostTypeId="1" AcceptedAnswerId="14403" CreationDate="2018-06-11T09:54:23.817" Score="1" ViewCount="115" Body="&lt;p&gt;I am using a untraviolet-visible spectrometer to measure Vertical Column Densities (VCDs) of trace gases up to the stratosphere. It is physically impossible to have negative VCDs. I have observed some of the measurements of slant column densities (SCDs) to be negative. mathematically, VCD = SCD/AMF. I was wondering whether AMF could be negative or the negative SCDs should be filtered out.&lt;/p&gt;&#xA;" OwnerUserId="12661" LastActivityDate="2018-06-11T15:21:44.530" Title="Can the Air Mass Factor (AMF) be negative?" Tags="|atmosphere-modelling|atmospheric-chemistry|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14400" PostTypeId="1" CreationDate="2018-06-11T03:36:34.310" Score="4" ViewCount="60" Body="&lt;p&gt;I mean meteorological visibility (as per &lt;a href=&quot;https://en.wikipedia.org/wiki/Visibility&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;, &quot;a measure of the distance at which an object or light can be clearly discerned.&quot;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to know if, before modern industry (say pre-1800 A.D.), visibility in rural areas was longer than it is today (in clear weather conditions, of course). If so, by how much?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Of course in smog-filled cities visibility is obviously limited by pollution. I'm asking about rural areas.)&lt;/p&gt;&#xA;" OwnerUserId="13153" OwnerDisplayName="nerdfever.com" LastEditorUserId="6" LastEditDate="2018-06-11T11:03:16.420" LastActivityDate="2018-06-11T14:13:12.600" Title="Was rural visibility (air transparency) longer in pre-industrial times?" Tags="|air-quality|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14401" PostTypeId="2" ParentId="14397" CreationDate="2018-06-11T13:53:30.253" Score="10" Body="&lt;p&gt;Your question has an incorrect assumption built in.  Near surface ground water temperatures are not generally colder, but rather reflect the average annual temperature. This will be colder than surface temps in summer, but warmer in winter.  There is an an additional effect if your rainfall isn't evenly distributed over the course of the year, as percolating rainfall will be initially warmed by warm soil temps in summer.  As an example, in central Alberta shallow well water temps run about 10 C, while our average temp for the year is around 4-5 C&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Start here: &lt;a href=&quot;https://www.builditsolar.com/Projects/Cooling/EarthTemperatures.htm&quot; rel=&quot;noreferrer&quot;&gt;https://www.builditsolar.com/Projects/Cooling/EarthTemperatures.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A graph on that page shows how soil temps vary with depth depending on seasonal variation, and moisture levels.  Ball park:  30 feet gets out out of the seasonal variation, but 12 feet eliminates about 2/3 of the annual variation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If your climate is cold enough in winter, it may be worth your while to store coolth in the form of brine.  In effect build a well insulated building with insulated foundation with what amounts to a swimming pool in it filled with either salt water brine, or calcium chloride brine.  Have a few thousand feet of 1/2&quot; plastic pipe (drip irrigation pipe is cheap)  both outside and in the pool, and circulate antifreeze through the pipe when winter temps are below the brine temp.  In the summer, a secondary loop circulates between the pool and the heat exchangers for the house.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are in a desert climate, you may be able to do something similar on a smaller scale.  Under a calm clear sky, you can often get frost on the side of an insulator facing the dark sky at night.  Modifying this idea, create a large bottom insulated surface coated with a good IR emitter (Titanium dioxide white is one such.) , and run shallow water over it.  If you can routinely get 30 C colder than day time air temps, then you only have to store a few days worth of coolth instead of a years worth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can make the system above colder by pre-chilling the water with an evaporative cooler&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit:  One source claims 1 degree F per 30 feet starting at around 100 feet.  Temperatures above this &#xA;however are highly variable from water movement.&lt;/p&gt;&#xA;" OwnerUserId="13145" LastEditorUserId="13145" LastEditDate="2018-06-14T12:59:22.843" LastActivityDate="2018-06-14T12:59:22.843" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14402" PostTypeId="2" ParentId="14400" CreationDate="2018-06-11T14:13:12.600" Score="2" Body="&lt;p&gt;Pre-industrial would mean that a lot of energy use would be the in-efficient use of wood burning.  I recall that part of J. S. Bach's payment at one of his posts was firewood provided by his employer -- something like &quot;8 cords of birch wood, 2 cords of Alder, split for kitchen use....  I think the list was about 15 cords of wood for a year.  Bach had a big household, but even so.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Flip side:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Certainly the use of coal at the start of the industrial age clouded up the air substantially.  See records of London 'pea soup' fogs.  Coal was used on farms too, but the spread out nature of farms would dilute it somewhat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I live in a rural area where many people heat with wood in winter, and some with coal.  At this point with an average of one household per square mile it makes little impact.  6 miles away is a coal fired power station.  On a really bad day I can just barely see it's plume.  The dust collection is pretty good.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In pre-industrial times, farms averaged about 5 acres per family unit, about 100 times the current Alberta farm density, and 1000 times Saskatchewan's farm density.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ok:  What are the contributors to visibility reduction:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Plant transpiration -- water vapour is a big one, but plants also put significant amounts of complex organics into the air.  Most of the 'Blue Ridge&quot; mountain haze is the result of plant activity.  This will change depending on ground cover.  Deciduous trees are more prone to this than grasses and forbs.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Dust from natural activities.  Only occurs in climates dry enough that ground cover is incomplete.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Man made dust.  Tillage in agriculture is the main cause of this, but watch any gravel road too.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Smoke from combustion.  Much depends on how stuff is burned.  Large particulates (e.g. diesel soot) fall out of the air column fairly quickly.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;My wild ass guess is that average visibility hit a minimum somewhere between 1930 and 1970 when tillage and coal use was at it's peak, but has since increased due to both less coal being burned, and better combustion design, along with increasing use of zero or minimal tillage in agriculture.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could get one check on this by looking at particulate measures in glacial ice.  &lt;/p&gt;&#xA;" OwnerUserId="13145" LastActivityDate="2018-06-11T14:13:12.600" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14403" PostTypeId="2" ParentId="14399" CreationDate="2018-06-11T15:21:44.530" Score="1" Body="&lt;p&gt;No, AMF is always positive. Depending on the retrieval algorithm, negative SCDs can occur as artifacts. You should look at your retrieval algorithm but in general I'd treat negative values in such a situation as &quot;below detection threshold&quot; values. Depending on what you are doing replacing them by 0 might be a valid course of action.&lt;/p&gt;&#xA;" OwnerUserId="681" LastActivityDate="2018-06-11T15:21:44.530" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14404" PostTypeId="1" CreationDate="2018-06-11T15:37:15.387" Score="3" ViewCount="337" Body="&lt;p&gt;Some years ago I had the chance to climb the Himalayas. Not the Everest of course, but the Annapurna Base Camp which is about 4km above sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During the night of the stay I went out to do some stargazing and I found that the night was very bright, so bright that I was able to make out letters on a book. (Of course I didn't read.) I figured that since there was practically no light coming from the ground within several kilometers to illuminate the air, the light from the moon and the stars were comparatively bright (just the opposite of why we can't see stars clearly from a city).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But recently it hit me that, well, night is supposed to be dark. Anyone who lived outside cities will tell me that.  Lack of light source from the ground will make the moon &lt;em&gt;appear&lt;/em&gt; brighter because there will be greater contrast but it won't make moonlight reaching the ground any brighter, will it? So this confused me. How was that night in the Himalayas so bright? Is it an expected thing if I'm so high up, or are there some factors that might have made that particular night so bright? Or are nights outside cities normally bright regardless of the altitude (assuming clear sky and near-full moon)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing I suppose could be the reason is that the thinner air due to the altitude meant there was less scattering of the light. I'm not sure if the air was thin enough to make such a difference though.&lt;/p&gt;&#xA;" OwnerUserId="13146" LastActivityDate="2018-06-11T15:37:15.387" Title="Why is the night very bright in the Himalayas?" Tags="|atmosphere|mountains|moon|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14405" PostTypeId="1" CreationDate="2018-06-11T21:11:13.363" Score="2" ViewCount="760" Body="&lt;p&gt;I've been searching for a map that shows all continents in their actual size that is free of projection distortion, to no avail. Every map I found was of a particular projection type and as such showed continents out of proportion. Even &lt;a href=&quot;http://blogs.discovermagazine.com/d-brief/2016/11/03/most-accurate-world-map/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one&lt;/a&gt;, that claims to &quot;not lie&quot; seems rather distorted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am no expert in the area, but I do have some 3D graphics background, so I decided to give it a go. I took a spherical projection map of the continental plates, projected it onto a sphere, then created a polygonal mesh encompassing all continents onto the sphere, then brought that into 2d space and relaxed edge length to correspond to their relative length in 3d space as much as possible and transferred the pixel information to the resulting UV map. Note that I did not account of the planet being an imperfect sphere, so that may be a source of minor inaccuracy. And the result:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QUWfQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QUWfQ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It does look a lot like a Dymaxion projection, although my result seems less distorted, probably because the former is project onto a rather low resolution mesh before unfolding:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Xg5CA.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Xg5CA.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is my result accurate enough, or is my workflow missing something? And in case of the latter, I'd appreciate a reference to an accurate representation, or at least some info on what I did wrong and how to improve my result.&lt;/p&gt;&#xA;" OwnerUserId="8457" LastEditorUserId="8457" LastEditDate="2018-06-11T21:53:21.150" LastActivityDate="2018-06-14T11:07:57.223" Title="Distortion-free map of all continents" Tags="|mapping|continent|projection|" AnswerCount="1" CommentCount="15" ClosedDate="2018-06-17T01:25:32.703" ContentLicense="CC BY-SA 4.0" />
  <row Id="14407" PostTypeId="1" CreationDate="2018-06-12T01:38:24.260" Score="2" ViewCount="72" Body="&lt;p&gt;The study area rang from 500 to 8000 m above ground and distributed into 4 elevation classes, above 5000,4-5000, 3-4000, below 3000 m above ground. This region has different climate zone/precipitation zone in term of amount and pattern. &#xA;What is the best way to detect the spatial and temporal pattern of precipitation in such region with monthly satellite data?&lt;/p&gt;&#xA;" OwnerUserId="12714" LastActivityDate="2018-08-11T13:01:11.717" Title="what is the best way to detect spatial and temporal pattern of precipitation in mountainous region?" Tags="|precipitation|mountains|geospatial|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14408" PostTypeId="2" ParentId="8787" CreationDate="2018-06-12T11:35:33.177" Score="4" Body="&lt;p&gt;I am not sure about the size of Krakatoa eruption but the eruption of Mt. Pinatubo in Indonesia around 12th June 1991 is considered as the largest eruption in the past 100 years. Global average of decrease in solar radiation after 4 months of eruption was about 2.7 +/- 1 W/m^2. Global average surface reaching solar radiation is about 198 W/m^2. In other words, Mt. Pinatubo eruption caused about 1.3% decrease. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The number 2.7 W/m^2 is a global average, so the decrease might have been more in tropical regions and less at high latitudes. It took about three years for stratospheric aerosol amount to return to the background level. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reference: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Minnis et al., 1993, &quot;Radiative climate forcing by the Mt. Pinatubo eruption&quot;, Science, vol. 259, 1411-1415, doi: &lt;a href=&quot;http://dx.doi.org/10.1126/science.259.5100.1411&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.1126/science.259.5100.1411&lt;/a&gt; &lt;/li&gt;&#xA;&lt;li&gt;Kremser et al., 2016, &quot;Stratospheric aerosol - observations, processes and impact on climate, Review of Geophysics, vol. 54, 278-335, doi:&lt;a href=&quot;http://dx.doi.org/10.1002/2015rg000511&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.1002/2015rg000511&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="10780" LastEditorUserId="10780" LastEditDate="2018-06-14T09:08:05.487" LastActivityDate="2018-06-14T09:08:05.487" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14409" PostTypeId="2" ParentId="14407" CreationDate="2018-06-12T12:53:28.413" Score="1" Body="&lt;p&gt;This is a non-trivial problem.  Short answer:  I don't think it can be done with monthly satellite data to a useful precision.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's where I started:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthobservatory.nasa.gov/Search/index.php?hq=site%3Aearthobservatory.nasa.gov%2FFeatures%2F&amp;amp;q=measuring+rainfall&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earthobservatory.nasa.gov/Search/index.php?hq=site%3Aearthobservatory.nasa.gov%2FFeatures%2F&amp;amp;q=measuring+rainfall&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They now have a tropical rainfall project.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthobservatory.nasa.gov/Features/TRMM/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earthobservatory.nasa.gov/Features/TRMM/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It uses space borne precip radar.  In the article above I didn't find specs on the resolution.  Looking elsewhere, it's temporal resolution is 1 month, and horizontal is .25 degree (about 18 miles) If your study zone has latitude under 35 degrees, it may be of use, but overall it seems too coarse.  I would expect a montane environment would require a resolution on the order of a kilometre. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even a simple rain gauge is problematic.  Go look at the siting requirements.  I suspect that parking one on a cliff at 6700m is going to give you non-conformant data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think synthetic aperture radar is being used to determine snowpack depth. &#xA;In the bad old days they hired people to go measure snow packs.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using corner reflectors on the surface where they would be buried in snow may give you better results.  You measure the attenuation from the snow on top of them.  Take substantial time and effort to calibrate. Big win:  You are measuring the mass of ice in the column, not the depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rainfall is much more difficult.  Water doesn't pile up and wait to be measured. &#xA;Or maybe you could stack it:  Consider a corner reflector at the bottom of a cone.  Choose a frequency that is somewhat absorbed by liquid water.  The cone is deliberately angled so that reflections off of it miss the transmitter.  So the corner reflector's signal is attenuated by the pile of water on it.  The cone magnifieds the water depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Weather radar can determine precipitation intensity, but using it in the mountains would mean getting returns of the mountain too.  Hard to sort. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Possibly put the radar on top of a mountain, and give it zero angle of elevation. In essence you would be measuring the amount of water passing through a disk. I don't think these instruments come in crackerjack boxes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, you said satellite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have known chokepoints in stream channels, you can monitor them using very high resolution imagery -- in effect you are using a natural weir.  However you need resolution in inches. I'm skeptical about the folks at Langley lending you their satellites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Might be possible to monitor the rise and fall of lake and ponds.  This requires a precision that I don't think is possible right now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Might be possible using a pair of corner reflectors.  One is fixed to the ground, the other floats in a plastic open top barrel.  Bounce microwave pulse and measure the difference in time.  This requires accurate timing.  A nanosecond is about 9 inches at speed of light.  You want to reliable measure 1/10 of this.  Centimeter band microwave should be able to do this.  You still have to place the instruments, and I suspect you will need to visit them to clean out dead leaves, bird nests, and replace instruments that have been damaged by moose and woodpeckers.  You will also need to do calibration measures to compare what the instrument in the open measures compared to ones under the tree canopy.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your upper levels are well above tree line, which means that as often as not, precipitation travels horizontally.&lt;/p&gt;&#xA;" OwnerUserId="13145" LastActivityDate="2018-06-12T12:53:28.413" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14410" PostTypeId="1" AcceptedAnswerId="14412" CreationDate="2018-06-12T13:42:43.290" Score="4" ViewCount="111" Body="&lt;p&gt;In the mainstream media the problem of ocean level rise is presented rather... over-simplistically - ice melts  -&gt; more water flows into the oceans -&gt; water level rises -&gt; continents sink.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But it is in reality a complex system, it is not like pouring water in a glass... or a lake that resides on a continental plate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both continental and oceanic plates float on top of the mantle as both are lighter and lower density, and both exert weight and compress the mantle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, if water is removed from continental plates by means of melting ice, the continental plate gets lighter. And when that water migrates to the ocean, the oceanic plate gets heavier. And since for every action there is equal in force and opposite in direction reaction, it seems logical that the now heavier oceanic plate will actually push the now lighter continental plate up, to some extent compensating for or possibly even reversing the change in ocean level relative to the continental plate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, do the estimates account for the dynamic properties of that complex system?&lt;/p&gt;&#xA;" OwnerUserId="8457" LastEditorUserId="8457" LastEditDate="2018-06-12T13:56:51.130" LastActivityDate="2018-06-12T15:50:31.087" Title="Do ocean level rise estimates account for mantle elasticity and plate mass changes?" Tags="|ocean|plate-tectonics|sea-level|earth-system|continent|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14411" PostTypeId="1" CreationDate="2018-06-12T15:17:56.320" Score="2" ViewCount="197" Body="&lt;p&gt;I regularly see articles like &lt;a href=&quot;https://www.bbc.co.uk/news/uk-scotland-44453764&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; where a country has or has committed to reduce their carbon emissions by a certain percentage in relation to a certain year. That article mentions that Scotland has dropped their emissions to 49% below 1990 levels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other discussions talk about cutting carbon to come under a 2 degree, or 3 degree warming level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How do these two relate?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If everyone goes back to 1990 how many degrees does the planet warm?&#xA;What do different 'years' look like 2000? 1960?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;edit: The answers given pretty much cover it but what I was really after was a bar graph or similar that says 1960: 0.3 degrees, 1990: 1.1 degrees, 2000: 2.0 degrees. ie how do year levels correspond to warming predictions.&lt;/p&gt;&#xA;" OwnerUserId="13152" LastEditorUserId="13152" LastEditDate="2018-06-19T15:46:53.043" LastActivityDate="2018-06-19T15:46:53.043" Title="To what year do we need to return to prevent climate change?" Tags="|climate-change|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14412" PostTypeId="2" ParentId="14410" CreationDate="2018-06-12T15:50:31.087" Score="6" Body="&lt;p&gt;Sea level rise estimates use changes in &lt;a href=&quot;http://www.coastalwiki.org/wiki/Relative_sea_level&quot; rel=&quot;noreferrer&quot;&gt;relative mean sea level&lt;/a&gt;. The definition being:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Relative sea level is the sea level related to the level of the continental crust. Relative sea level changes can thus be caused by absolute changes of the sea level and/or by absolute movements of the continental crust. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In general, &lt;a href=&quot;https://en.wikipedia.org/wiki/Sea_level&quot; rel=&quot;noreferrer&quot;&gt;Mean Sea Level&lt;/a&gt; means the 'water level when it is still' (without waves). MSL is averaged over a determined period of time, such as a month or a year and it is measured relative to a fixed mark on the land (benchmark).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As MSL is measured relative to land, it can change due to changes in water volume or due to land movements. That is why we usually refer to it as 'relative sea level'. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Long-term changes of sea level are called &quot;secular&quot; changes and include isostatic changes. The main reason for isostatic changes at a global scale is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Post-glacial_rebound&quot; rel=&quot;noreferrer&quot;&gt;Glacial Isostatic Adjustment&lt;/a&gt; (GIA).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The body of scientific work related to the contributions by different factors is extensive. For instance, I like &lt;a href=&quot;https://doi.org/10.1029/2003RG000139&quot; rel=&quot;noreferrer&quot;&gt;Cazenave &amp;amp; Nerem, 2004&lt;/a&gt;. Also, there is a lot of information about &lt;a href=&quot;https://sealevel.jpl.nasa.gov/science/ostscienceteam/scientistlinks/scientificinvestigations2013/cazenave/&quot; rel=&quot;noreferrer&quot;&gt;the relative contributions of each&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dFSot.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dFSot.jpg&quot; alt=&quot;contributions&quot;&gt;&lt;/a&gt; Source: &lt;a href=&quot;https://sealevel.jpl.nasa.gov/science/ostscienceteam/scientistlinks/scientificinvestigations2013/cazenave/&quot; rel=&quot;noreferrer&quot;&gt;JPL-NASA&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a lot more information about the regional distribution of sea level rise in: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/10876/how-will-sea-level-rise-be-distributed-across-the-globe&quot;&gt;How will sea level rise be distributed across the globe?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, &lt;a href=&quot;http://homepages.see.leeds.ac.uk/~lecimb/SOEE3410/lectures/15-Sea-level-rise.ppt&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; is a good simple explanation of the factors affecting sea level.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2018-06-12T15:50:31.087" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14413" PostTypeId="1" AcceptedAnswerId="14422" CreationDate="2018-06-13T05:00:48.033" Score="1" ViewCount="44" Body="&lt;p&gt;Assume there are several soil/rock (take it) samples as follows taken from different depth of the earth&lt;/p&gt;&#xA;&#xA;&lt;p&gt;sample from surface of the earth = Sample A&lt;br&gt;&#xA;sample from 1km deep of the earth = Sample B&lt;br&gt;&#xA;sample from 10km deep of the earth = Sample C&lt;br&gt;&#xA;sample from 20km deep of the earth = Sample D&lt;br&gt;&#xA;Cooled lava (in solid state) sample = Sample E  (Assume lava was taken just after they cooled)         &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If these samples are tested using carbon 14 test what will be there ages according to test results?       &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;NOTE: I'm not expecting any exact values.&lt;br&gt;&#xA;  Please order them in ascending order           &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As I think it should be in the order of A&#xA;Because with the time new layer of soil/rock creates on top of the current existing layer and it's obvious(as I think) layer 1(first existed layer as the top layer) that first layer is older than new layer.&lt;br&gt;&#xA;Above is my explanation.&lt;/p&gt;&#xA;" OwnerUserId="13154" LastEditorUserId="13154" LastEditDate="2018-06-14T11:35:37.400" LastActivityDate="2018-06-14T12:44:42.873" Title="What would be the predicted/calculated ages using several samples of soil with the help of carbon 14 test?" Tags="|age|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14414" PostTypeId="1" AcceptedAnswerId="14464" CreationDate="2018-06-13T12:49:18.410" Score="3" ViewCount="2385" Body="&lt;p&gt;Body waves (to some extent) and especially surface waves show &lt;em&gt;dispersive&lt;/em&gt; characteristics during propagation. In Dr. Christopher Liner's book [&lt;em&gt;Elements of Seismic Dispersion&lt;/em&gt; (2012)], this phenomenon is quickly attributed to propagating seismic energy being &lt;em&gt;frequency-dependent&lt;/em&gt;. I've heard this phrase for a long time, and I am still unsure how to visualize and/or quantify it for the sake of really understanding this phenomenon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Indeed, why can't one phrase it as being &lt;em&gt;wavelength-dependent&lt;/em&gt; as well? Also, for both surface and body waves, what are the primary factors that cause/generate seismic dispersion?&lt;/p&gt;&#xA;" OwnerUserId="8447" LastEditorUserId="6465" LastEditDate="2018-06-13T14:52:27.210" LastActivityDate="2022-12-21T01:38:47.197" Title="Seismic dispersion: What does it really mean and what causes it?" Tags="|seismic|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14419" PostTypeId="2" ParentId="14405" CreationDate="2018-06-14T11:07:57.223" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;I've been searching for a map that shows all continents in their actual size that is free of projection distortion, to no avail&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That's because such a thing does not exist. A projection by definition has distortion, otherwise it would not be a projection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only way to have a distortion free view of the planet is by having a physical globe, and looking at it with both eyes so your brain gets the three dimensional perception (assuming going to space is not an option). Anything else will result in distortion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now that we have this covered, there are all kinds of projections with all kinds of distortions. Distortions can affect areas, distances, shapes, etc. to various degrees. It's your choice to determine which types of distortions and their magnitudes are acceptable to you, personally. There is no need to reinvent the wheel, there are enough projections out there already.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-06-14T11:07:57.223" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="14422" PostTypeId="2" ParentId="14413" CreationDate="2018-06-14T12:20:42.013" Score="4" Body="&lt;p&gt;Radiocarbon dating cannot be used to date rocks or lava, &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiocarbon_dating&quot; rel=&quot;nofollow noreferrer&quot;&gt;only organisms that absorbed carbon from the atmosphere in the last 50'000 years or so.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The older the samples, the more difficult it is to get an accurate age because the amount of 14C remaining becomes close to zero and thus the more likely it is that a few atoms of 14C from sample handling or atmospheric exposure may significantly change the number. &lt;a href=&quot;https://journals.uair.arizona.edu/index.php/radiocarbon/article/view/1127/1132&quot; rel=&quot;nofollow noreferrer&quot;&gt;That is why, for instance, coal contains trace amounts of 14C&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;More generally, sample age does not always correlate with sample depth and it is strongly dependent on the geological setting. &lt;a href=&quot;https://en.wikipedia.org/wiki/Law_of_superposition&quot; rel=&quot;nofollow noreferrer&quot;&gt;In a sedimentary basin, deeper rocks are older than shallower rocks&lt;/a&gt; but tectonic activity such as thrust faults and folds can upset this relationship.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In granitic and metamorphic terranes, there is no general correlation of age with depth, &lt;a href=&quot;https://en.wikipedia.org/wiki/Methods_of_pluton_emplacement&quot; rel=&quot;nofollow noreferrer&quot;&gt;because granites intrude into older rocks&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4783" LastActivityDate="2018-06-14T12:20:42.013" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14424" PostTypeId="2" ParentId="14413" CreationDate="2018-06-14T12:44:42.873" Score="1" Body="&lt;p&gt;Geochron's answer is correct. For the sake of completeness I will add this:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;sample from surface of the earth = Sample A&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You will get some age, if the sample is young enough.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;sample from 1km deep of the earth = Sample B&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Low chance of getting any age.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;sample from 10km deep of the earth = Sample C&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Carbon-14 below detection limit.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;sample from 20km deep of the earth = Sample D&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Carbon-14 below detection limit.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Cooled lava (in solid state) sample = Sample E (Assume lava was taken just after they cooled) &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Carbon-14 below detection limit.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;I'll also add is that we are very limited in our capability to obtain samples from 10 or 20 kilometres deep.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-06-14T12:44:42.873" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14425" PostTypeId="2" ParentId="14380" CreationDate="2018-06-14T13:25:32.623" Score="1" Body="&lt;p&gt;Hmm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some of this depends on how you view desertificaiton.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A:  The arbitrary definition for desert usually is 'an area receiving under 10 inches of precipitation a year&quot;  By this definition the arctic is a cold desert, and is very wet.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;B:  Our mental image of desert is 'hot, dry, sparse vegetation, very sparse habitation'&lt;/p&gt;&#xA;&#xA;&lt;p&gt;C:  Desertification is usually viewed as a process that changes an arid region to one of deserts.  There are various causes of this:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Overgrazing.  Herbivores (goats and sheep often, but also camels, cows...)  Reduce the biomass.  Because plants aren't transpiring, overall rainfall drops, more clear days means wider temperature swings, harder for plants to get re-established.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Rain pattern shifts -- either time of year, or prolonged drought.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In the early days of LandSAT, scientists found a perfectly regular pentagon of green vegetation in the sub Sahara.  On sending out field agents, they found that some enterprising person had fenced in several square miles of desert scrubland.  At the centre was a well.  He grazed livestock on each triangle in succession on a 5 year rotation.  Because the land had 4 years to recover, it worked.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The well wasn't used to irrigate the fields, but only to supply water for the stock.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;One of the potential issues with farming solar power:  Solar cells are quite dark, and while some 20% of the energy that hits them is converted to electricity, the rest is converted to heat.  The net effect is an decrease in the overall reflectivity, and an overall heating up of the region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hot air rises, so now you have a thermal column rising from the solar farm.  Depending on local humidity, this can create an overcast layer that interferes with the solar farm.  Small units (a mile or do across) won't shade themselves, but really massive farms may create their own interference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;OTOH, some of the ground is shaded, at least part of the day.  Lower temps = lower water demand by plants.  You may be able to grow plants you otherwise couldn't grow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the third hand, if you are close to the sea, it may be possible to harvest that surplus heat to evaporate sea water.  This moderates temperatures, but increases humidity.  Can you get fresh water out of this?&lt;/p&gt;&#xA;" OwnerUserId="13145" LastActivityDate="2018-06-14T13:25:32.623" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14426" PostTypeId="1" AcceptedAnswerId="14427" CreationDate="2018-06-14T16:57:40.447" Score="4" ViewCount="2949" Body="&lt;p&gt;After looking at this &lt;a href=&quot;https://earthscience.stackexchange.com/questions/12396/why-does-the-intensity-of-sunlight-depend-on-your-latitude&quot;&gt;post&lt;/a&gt; I can see that a flat object is more exposed to the sun at the equator. Does this mean that a person walking around (standing up), is much more likely to burn at the poles than at the equator? Because their entire body is facing the sun, not just the top of their head?&lt;/p&gt;&#xA;" OwnerUserId="13168" LastActivityDate="2018-06-18T13:18:37.177" Title="Are you more likely to get a sunburn at the pole than the equator?" Tags="|meteorology|sun|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14427" PostTypeId="2" ParentId="14426" CreationDate="2018-06-14T17:33:37.067" Score="2" Body="&lt;p&gt;Assuming that your skin is exposed, you are standing upright are out when the sun is out, yes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You don't even need to be very polar.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I live near Edmonton Alberta -- latitude 54 degrees.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the equinox, the sun is at 54 degrees from the zenith.  At winter solstice it is 54 + 23 = 77 degrees from the zenith, or 13 degrees off the horizon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No joke:  We use our car's sun-visors driving south at noon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if I'm standing up outside, I'm getting roughly the kind of sun intensity you would get lying flat on the beach in more tropical climes.  Since you aren't really hot, you can get a burn without your usual warning signs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Confounding factors:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sunlight is traveling through more atmosphere which reduces intensity somewhat.  At 13 degrees, the light path has about 4 times as much air in the path.  Which increases the amount of sunlight that is absorbed -- but not by a factor of 4.  The difference between sunlight in space and sunlight at the surface is about 30% overall, but adding to the air column will only increase the absorption of frequencies that are partially absorbed by a more vertical column.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Polar latitudes, and less polar ones in winter when solar angles are low, will tend to have less dust, water and smoke in the air, increasing air's transparency.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You get reflection off the snow which can come close to doubling your exposure.  Some of the worst sunburn's I've gotten have been on winter days on my poor nose.  (Sticking out of my face it's getting direct sun, reflected off of snow, and reflected off of face.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One useful measure of the relative intensity is to look at the exposure information for photographs.  (You have to know the film speed or digital ISO as well as shutter speed and f/stop) I find that exposures in sunlight at 'low noon' in winter are comparable to summer ones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Day lengths are short.  At winter solstice we theoretically have about 9 hours of daylight.  When the sun peaks at 13 degrees however there are a lot of shadows. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The weather tends to discourage large displays of skin, although I've split wood without a shirt on a calm sunny day at -10 C.  In general when dressing for outdoors I figure that bright sun in winter is equivalent to 10-15C degrees warmer, since it's hitting more of me.&lt;/p&gt;&#xA;" OwnerUserId="13145" LastEditorUserId="13145" LastEditDate="2018-06-18T13:18:37.177" LastActivityDate="2018-06-18T13:18:37.177" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14428" PostTypeId="2" ParentId="14318" CreationDate="2018-06-14T17:53:11.027" Score="1" Body="&lt;p&gt;In practice you &lt;em&gt;really&lt;/em&gt; don't want to plant a field that is even close to capacity.  Doing so will result in ruts, soil compaction, breakdown of soil structure and a large increase in fuel consumption.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the advantages of zero tillage systems is the ability to get out on the field in wetter (earlier in spring) conditions.  All those roots help reduce the sheering between soil particles.&lt;/p&gt;&#xA;" OwnerUserId="13145" LastActivityDate="2018-06-14T17:53:11.027" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14429" PostTypeId="2" ParentId="14411" CreationDate="2018-06-15T10:49:43.110" Score="3" Body="&lt;p&gt;As Gemechu Fanta Garuma commented, the IPCC Assessment Reports (at time of writing, &lt;a href=&quot;http://ipcc.ch/report/ar5/&quot; rel=&quot;nofollow noreferrer&quot;&gt;AR5&lt;/a&gt; is the latest) and its &lt;a href=&quot;http://ipcc.ch/publications_and_data/publications_and_data_reports.shtml#2&quot; rel=&quot;nofollow noreferrer&quot;&gt;special reports&lt;/a&gt; are the best place to go for a comprehensive summary of the science as it was a small number of years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of greenhouse-gas concentrations that are stable and civilisation-friendly, the range 300-350ppm CO2 is as useful a range as we're likely to get for now - &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0025326X09003816&quot; rel=&quot;nofollow noreferrer&quot;&gt;350 is when coral bleaching starts to become a serious problem&lt;/a&gt;, and trashing the ocean ecosystem is a shortcut to threatening human civilisation, so we should probably avoid that. And for methane, say around 1000-1300ppb. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's not a question of &quot;returning to a year&quot;. We don't need a time machine, and we don't need to wind back &lt;em&gt;everything&lt;/em&gt; that's happened. I've no wish to return to 1980, for example, and I'm not sure why anyone else would (I was there and it was largely rubbish). &lt;strong&gt;This is not about undoing decades of human progress.&lt;/strong&gt; What we do need to do is to keep the concentration of greenhouse gases in the atmosphere at levels that keep the climate fairly stable at the timescales of human lifetimes, so that we avoid massive disruptions and a potential threat to human civilisation. Had we started doing that when this was first flagged up as a major issue by scientists in the 1970s, we would have done it much cheaper, much sooner, and with less collateral damage. (like in the old proverbs: an ounce of prevention is worth a pound of cure; and a stitch in time saves nine)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://350.org/science/&quot; rel=&quot;nofollow noreferrer&quot;&gt;We have already caused some climate change.&lt;/a&gt; It will take 30 years for the full effects of what we've done to date, to show up. We may already have caused trillions of pounds of damage to our natural capital - but we'll only know the full scale of the damage when it's far too late. Theoretically, we could avoid some of that damage in the next 30 years by putting the global economy to work to tackle the problem seriously. However, the political will just isn't there. Most of the people who'll suffer the worst of the damage are too young to vote, or haven't been born yet. Most of the people with the ability to do something about it (voters, politicians, business leaders) will be dead before the worst of the damage hits.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Keeling Curve shows how atmospheric CO2 concentrations have changed over time:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hc4WT.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hc4WT.jpg&quot; alt=&quot;Keeling Curve&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;(chart Scrippsnews - Own work, CC BY-SA 4.0, &lt;a href=&quot;https://commons.wikimedia.org/w/index.php?curid=69539214&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://commons.wikimedia.org/w/index.php?curid=69539214&lt;/a&gt;)&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the relationship between atmospheric concentrations of greenhouse gases, the change in average global temperatures, and actual changes in climate, that's a set of very complex relationships wrapped in uncertainties and unknowns. And these things are generally nowhere near as simple as a neat, reversible one-to-one function: even if we were to restore greenhouse gas concentrations to where they were in 1980, does not mean that the climate will return to just as it was then.  And that's why mitigation action is so very urgent: we are driving in thick fog very close to the edge of a cliff. The smart thing to do is to stop driving and work out what's going on. Which means getting to zero net emissions as fast as we can without destroying everything else in the process.&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="100" LastEditDate="2018-06-15T13:06:40.503" LastActivityDate="2018-06-15T13:06:40.503" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14430" PostTypeId="2" ParentId="14300" CreationDate="2018-06-15T12:19:45.487" Score="2" Body="&lt;p&gt;You have an unclear question. See my comment on the question itself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Answering just the question:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've not seen a formal  definition of arctic greening.  Conceptually it's replacing a landscape that is in effect a cold desert with one that has:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Longer growing season.&lt;/li&gt;&#xA;&lt;li&gt;Greater biodiversity&lt;/li&gt;&#xA;&lt;li&gt;Greater gross photosynthesis.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;You would think that it would also be greater net photosynthesis too, but much of the arctic has large deposits of peat moss, forest duff and sedges. With warmer temperatures we will likely see greater bacterial action on the peat. Not clear which way the carbon/acre figure will move.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's also not clear what the effect of an open oceans in the high arctic will be.  Depending on the nutrient levels in those waters could see a lot more phytoplankton. BVOC exchange between ocean and atmosphere?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can get a first level approximation substituting latitude for time. I expect BVOCs to disperse fairly quickly so you would need to measure at ground level. Analyzing a bunch of sites that are representative of the various major communities -- Boreal forest, tree line, tundra/puckey-brush (scrub willow, birch) Tundra/moss, forbs; Rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a preliminary analysis you don't even need to go to the arctic. Use a convenient mountain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That can nail down quantities of BVOCs. Correlate that with HCOH to see how good a proxy HCOH is for BVOC.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This leaves a bunch of unanswered questions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the time frame for the degradation of HCOH similar to for other BVOCs?  You may have to do radioactive tracer tests in containers set at similar conditions of temperature, pressure and UV illumination.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the degradation products?  What are the effects of these?  Do any of the original products or their degradation products acts as catalysts?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think you have bitten off a big research project.&lt;/p&gt;&#xA;" OwnerUserId="13145" LastEditorUserId="6465" LastEditDate="2018-06-15T17:45:35.290" LastActivityDate="2018-06-15T17:45:35.290" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14431" PostTypeId="1" CreationDate="2018-06-15T19:18:46.627" Score="0" ViewCount="83" Body="&lt;p&gt;My co-worker had this rock and told me found just behind the store, Big R, and put on the table in the office.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Location is Trindad, Colorado.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4sPM8.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4sPM8.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/InZkN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/InZkN.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6q2hn.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6q2hn.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5771" LastActivityDate="2018-06-16T06:45:38.963" Title="Rock identification ? What kind of it is?" Tags="|rocks|" AnswerCount="1" CommentCount="1" ClosedDate="2019-08-29T19:43:35.443" ContentLicense="CC BY-SA 4.0" />
  <row Id="14433" PostTypeId="2" ParentId="14392" CreationDate="2018-06-15T23:31:49.507" Score="1" Body="&lt;p&gt;I suggest you consider the concept of radiative forcing. It is the net change in energy balance at the top of the atmosphere due to imposed perturbation. The change in radiative forcing is a function of multiples of factors: water vapor, solar radiation, anthropogenic and natural emissions of CO$_{2}$, etc. So, attempting to quantify future temperature to a single forcing may not be a good way of relating the two vars. You may consider running climate models that consider the above factors. &#xA;However, you can play around with single var relation you suggested. I can proved an alternative derivation that considers radiative forcing. &#xA;The relation between temperature perturbation and radiative forcing is &#xA;$$\Delta T = \lambda RF$$&#xA;where $\lambda$ is the climate sensitivity parameter and RF is a radiative forcing due to a particular perturbation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The above equation can be re-written,&#xA;$$T - T_{o} = \lambda RF $$&#xA;where $T_{o}$ is a particular reference temperature. You can take base period temperature (e.g., 1980 to 2015). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming temperature increases steadily in time, $T=T_{o}e^{ct}$, and inserting into the above equation,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$T=\lambda RF (\frac{1}{1-e^{-ct}})$$&#xA; Now you have $\lambda $ and  RF as coefficients. &lt;/p&gt;&#xA;" OwnerUserId="4877" LastActivityDate="2018-06-15T23:31:49.507" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14435" PostTypeId="2" ParentId="14431" CreationDate="2018-06-16T06:45:38.963" Score="2" Body="&lt;p&gt;Looks like slate to me. &#xA;&lt;a href=&quot;https://ngmdb.usgs.gov/Prodesc/proddesc_9346.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;The geological map of Trinidad suggests that the local rocks are shale, which is similar to slate but less compact.&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="4783" LastActivityDate="2018-06-16T06:45:38.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14436" PostTypeId="1" CreationDate="2018-06-16T08:13:52.870" Score="1" ViewCount="895" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FJJEm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FJJEm.jpg&quot; alt=&quot;The Different Types of Volcanoes&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;sub&gt;(source: &lt;a href=&quot;https://sciencetrends-techmakaillc.netdna-ssl.com/wp-content/uploads/2017/11/volcanoes-700x230.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;netdna-ssl.com&lt;/a&gt;)&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;In these popular diagrams for the three types of volcanoes, it seems as though the lava flows are inside the mountain. I suspect that they're trying to show rivers flowing on the surface (with an awkward illustration), though. So my questions are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Are these rivers flowing on the surface or are they inside the mountain?&lt;/li&gt;&#xA;&lt;li&gt;Is the lava flowing down from the top of the vent or is it branching out from somewehere in the pipe?&lt;/li&gt;&#xA;&lt;li&gt;Why doesn't the cinder cone have any lava flows?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="13175" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-02-20T08:24:21.353" Title="Are there lava flows inside a volcano?" Tags="|volcanology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14437" PostTypeId="1" CreationDate="2018-06-16T17:50:58.237" Score="0" ViewCount="232" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Is7eN.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just wondered if this was accurate. Sorry for poor grammar. Typing on pgomw.&lt;/p&gt;&#xA;" OwnerUserId="13177" LastEditorUserId="2470" LastEditDate="2018-06-17T08:32:43.220" LastActivityDate="2018-06-17T11:17:01.430" Title="Temperature graph for solar" Tags="|geography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14439" PostTypeId="2" ParentId="10617" CreationDate="2018-06-17T09:11:10.783" Score="2" Body="&lt;p&gt;NASA has just published (16 June 2018) a &lt;a href=&quot;https://earthobservatory.nasa.gov/IOTD/view.php?id=92295&quot; rel=&quot;nofollow noreferrer&quot;&gt;similar picture&lt;/a&gt; on its Earth Observatory website.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The pictures in the question were taken after &lt;a href=&quot;https://earthobservatory.nasa.gov/NaturalHazards/view.php?id=92189&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tropical Cyclone Mekunu&lt;/a&gt; passed over the region in May 2018.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The grey, metallic looking shapes are interdune sand flats filled with rain water.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-06-17T09:11:10.783" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14440" PostTypeId="1" CreationDate="2018-06-17T10:38:00.980" Score="3" ViewCount="136" Body="&lt;p&gt;I'm writing a toy radiative-convective atmospheric model and need to relate the heat flux convergences (either surface sensible heat flux or the radiative flux) to changes in atmospheric layer temperatures. The first law of thermodynamics states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The change in internal energy of a closed system is equal to the amount of heat supplied to the system plus the work done on the system by the surroundings.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My question is: Should gravitational potential energy be directly incorporated into this in any way, and where? When I calculate the internal energy of the layer, should that be just the thermodynamic internal energy $\rho c_v T$ or should it also include the potential energy $\rho g z$? The pressure work done on the system by its surroundings at the bottom of the layer is $p_{bot} \Delta z_{bot}$, which is clearly related to the raising and lowering of the layer. Should this work then be excluded from the RHS if the potential energy is excluded from the LHS?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I essentially have the following possibilities for calculating the change in temperatures:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;$\int_{z_{bot}}^{z_{top}} dz \, \rho c_v \Delta T = \Delta E_{rad}$&lt;/li&gt;&#xA;&lt;li&gt;$\int_{z_{bot}}^{z_{top}} dz \, (\rho c_v \Delta T + \rho g z) = \Delta E_{rad}$&lt;/li&gt;&#xA;&lt;li&gt;$\int_{z_{bot}}^{z_{top}} dz \, \rho c_v \Delta T = \Delta E_{rad} + p_{bot} \Delta z_{bot} - p_{top} \Delta z_{top}$&lt;/li&gt;&#xA;&lt;li&gt;$\int_{z_{bot}}^{z_{top}} dz \, (\rho c_v \Delta T + \rho g z) = \Delta E_{rad} + p_{bot} \Delta z_{bot} - p_{top} \Delta z_{top}$&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;It seems like the first and last of these are equivalent (at least assuming hydrostatic balance), but the first would use the isochoric heat capacity and the last the isobaric heat capacity. I believe the last one is the correct choice but I feel very unsure about it. The same dilemma persists when a surface heat flux is applied, or convection changes the height of the upper atmosphere without changing any of its temperatures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Relatedly, the full equation in a fluid dynamics point of view would include kinetic energy, and for an RCE model that would be turbulent kinetic energy. Should this be tracked? If I exclude it, is that the same as assuming that all kinetic energy gets turned into heat by viscosity between each timestep?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(These may be very basic questions to some of you, but for the life of me I can't convince myself of the right approach to take. I don't have any of my atmospheric science books with me, so if you throw in a reference, please make it to an online resource.)&lt;/p&gt;&#xA;" OwnerUserId="1342" LastActivityDate="2018-06-17T10:38:00.980" Title="Internal energy, enthalpy, and work in the atmosphere" Tags="|models|atmosphere-modelling|thermodynamics|atmospheric-circulation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14441" PostTypeId="2" ParentId="14437" CreationDate="2018-06-17T11:17:01.430" Score="1" Body="&lt;p&gt;This can't possibly be right without some type of filtering applied to the total solar irradiance, at the very least. There's a graph here:&lt;br&gt;&#xA;&lt;a href=&quot;https://www.nasa.gov/topics/earth/features/glory_irradiance.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nasa.gov/topics/earth/features/glory_irradiance.html&lt;/a&gt;&lt;br&gt;&#xA;showing the total solar irradiance measured primarily from satellites (i.e. from space) over the last several decades. There is no such trend in total solar irradiance from 1970 to now as the one shown.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The attribution is to the Berkeley Earth Surface Temperature Project, now Berkeley Earth. You can see a very different-looking temperature graph under their summary of findings:&lt;br&gt;&#xA;&lt;a href=&quot;http://berkeleyearth.org/summary-of-findings/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://berkeleyearth.org/summary-of-findings/&lt;/a&gt;&lt;br&gt;&#xA;Reverse image searching the image led me to this thread (&lt;a href=&quot;https://www.skepticalscience.com/solar-cycles-global-warming.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.skepticalscience.com/solar-cycles-global-warming.htm&lt;/a&gt;) and a couple others, which point to this article (&lt;a href=&quot;https://www.washingtontimes.com/news/2012/sep/6/global-warming-fanatics-take-note/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.washingtontimes.com/news/2012/sep/6/global-warming-fanatics-take-note/&lt;/a&gt;) as an original source for the graph. That webpage no longer has any graph, from what I can see, but the thread seemed to imply that the graph may have been hand-drawn and with no real sources.&lt;/p&gt;&#xA;" OwnerUserId="1342" LastActivityDate="2018-06-17T11:17:01.430" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14445" PostTypeId="2" ParentId="14414" CreationDate="2018-06-17T14:21:10.110" Score="1" Body="&lt;p&gt;Frequency- or wavelength-dependent are indeed equally valid terms but frequency is in practice more measurable than wavelength, so much so that seismic wavelength is calculated not measured. Dispersion is caused by material density, the material the waves pass through will, depending on density, pass certain waves, and wavelengths of those waves, better than other waves and wavelengths.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Describing my visualisation of the effect is difficult, the best way to look at the effect is to find seismic traces of the same earthquake from various ranges. This will show the different wave fronts spreading out as they travel. This is largely due to their compatibility with the material they pass through. I find it comparable to &lt;a href=&quot;https://en.wikipedia.org/wiki/Resonance&quot; rel=&quot;nofollow noreferrer&quot;&gt;structural resonance&lt;/a&gt; there are frequencies that interact well with the rock they're travelling through, they get a boost, and there are those that interact less well, they get held back by the material they're travelling through.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-06-17T14:21:10.110" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14447" PostTypeId="1" CreationDate="2018-06-17T14:35:08.267" Score="3" ViewCount="56" Body="&lt;p&gt;Take a specific point at sea level (less than 100 meters above it) on a &quot;trade wind&quot; oceanic route. For example, somewhere on Labrador-Ireland route, at roughly 50 degrees of latitude north. Let's say, early July to late October. Supposedly, I should find &quot;nearly constant&quot; winds blowing roughly west to east there. My question is about that &quot;nearly&quot;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;For how many &lt;em&gt;consecutive&lt;/em&gt; days should I expect the wind to blow unabated (let's say, at a minimum of 4 knots) at that point?&lt;/strong&gt; With &quot;blow unabated&quot;, I mean &quot;blow without a single second of interruption&quot;. If it matters at all, note that I am interested only in wind force, not direction: if the wind were to turn 180 degrees but still kept blowing at 4 knots or stronger, I'd still consider it unabated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is probably a very naive question, and despite my best efforts may be missing crucial details. In general, any pointer to information that helped me understand these &quot;gaps in average wind circulation&quot; would be greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="13178" LastEditorUserId="13178" LastEditDate="2018-07-20T15:03:20.417" LastActivityDate="2018-07-20T15:06:47.420" Title="For how long can the wind blow unabated on a &quot;trade wind route&quot;?" Tags="|meteorology|wind|weather-forecasting|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14448" PostTypeId="2" ParentId="14436" CreationDate="2018-06-17T14:55:16.120" Score="4" Body="&lt;p&gt;This is largely an issue of trying to show three dimensional structures in a two dimensional medium. It is also an issue of trying to differentiate between different materials and volcanic behaviours.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Volcanoes can be composed of three types of material: Country Rock is the material they're erupting up through it's usually sedimentary near the surface and gets buried under volcanic rocks relatively quickly, so much so that few diagrams include it. The other two rock types are volcanic in origin these are Cinders and Lava. Cinder is material thrown out of the volcano, this is usually &lt;a href=&quot;https://en.wikipedia.org/wiki/Scoria&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scoria&lt;/a&gt; but can include other &lt;a href=&quot;https://en.wikipedia.org/wiki/Tephra&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tephra&lt;/a&gt; as well, importantly it lands as a solid. Lava is the liquid rock that flows continuously from a volcanic vent. These two volcanic rock types are usually mutually exclusive, eruptions with lava have few cinders and vice versa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are three basic &quot;plan-forms&quot; of volcano Basalt Shields, Cinder Cones, and Composite Cones.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Basalt Shields form slowly from layer upon layer of lava flows that solidify one atop another over long periods of time they are correspondingly flat. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;At the other end of the eruptive spectrum are steep Cinder Cones formed from more violent eruptions that throw a lot of material out of the volcano, that rock solidifies as it flies through the air and lands around the vent. The closer you are to the vent the more material there is landing and the bigger it tends to be so a cone builds up, the angle of it's sides being governed by the average size of rock landing at that point. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Composite Cones are exactly what the name says; cones built up from a combination of Cinder and Lava from separate eruptions, some gentle and others violent. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The diagrams you've presented are an attempt to differentiate between these three plan-forms based on the nature of the volcanic material involved, using a deceptively simple palette. In active volcanoes there usually &lt;em&gt;are&lt;/em&gt; lava distribution systems that move laterally through the visible cone, these feed &lt;a href=&quot;https://en.wikipedia.org/wiki/Parasitic_cone&quot; rel=&quot;nofollow noreferrer&quot;&gt;lateral vents&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Lava_tube&quot; rel=&quot;nofollow noreferrer&quot;&gt;lava tubes&lt;/a&gt; moving material far from the central vent.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-06-17T14:55:16.120" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14450" PostTypeId="1" CreationDate="2018-06-17T19:14:02.697" Score="3" ViewCount="375" Body="&lt;p&gt;I don't want to start any controversy. I'm just curious about what could professional geologists say about this paper, and what is it's current scientific status, since I couldn't find any serious discussion about the subject online.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The paper is the following, by Paul Giem:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.grisda.org/origins/51006.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.grisda.org/origins/51006.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is told that the amount of carbon 14 that he found on diamonds and other fossil samples is impossible from the viewpoint that these samples are millions of years old. Were his finding subsequently discussed or disproved?&lt;/p&gt;&#xA;" OwnerUserId="13181" LastActivityDate="2018-06-18T09:45:17.683" Title="Giem's article on carbon dating" Tags="|dating|radioactivity|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14451" PostTypeId="1" AcceptedAnswerId="14454" CreationDate="2018-06-18T04:11:56.480" Score="4" ViewCount="193" Body="&lt;p&gt;The information discussed in the CleanTechnica article &lt;a href=&quot;https://cleantechnica.com/2018/06/16/full-fledged-5-alarm-climate-emergency-in-antarctica/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Full Fledged 5 Alarm Climate Emergency In Antarctica&lt;/a&gt; is certainly disconcerting, but the stock photo of the sky and various atmospheric phenomena of sunlight scattered in the atmosphere is still beautiful. My question is about this photo.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I see two circles around the sun, meaning light is scattered at certain angles ABC where B is the scatterer, A is the Sun, and C is the observer. However there are several features that are oriented with respect to the &lt;em&gt;the local horizontal and vertical&lt;/em&gt; as well. For example, a long line extending to the left and right from the Sun parallel to the &lt;em&gt;horizon&lt;/em&gt; with bright spots where it intersects the inner ring, and the beginnings of arcs, tangent to the &lt;em&gt;tops&lt;/em&gt; of the circles but curving &lt;em&gt;vertically upward&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Why are these patterns of scattered sunlight aligned to the local horizontal and vertical directions?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/v0fpX.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/v0fpX.jpg&quot; alt=&quot;Scattered sunlight pattern on a cold day&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2018-11-06T01:46:44.987" LastActivityDate="2020-06-28T02:45:02.513" Title="Why are these patterns of scattered sunlight aligned to the local horizontal and vertical directions?" Tags="|atmospheric-optics|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="14452" PostTypeId="1" CreationDate="2018-06-18T08:07:12.890" Score="1" ViewCount="100" Body="&lt;p&gt;Can someone explain why the lithosphere thickness varies within a short distance (30-100km) at the same upper mantle viscosity around the polar region?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And what is the behaviour of a thin (20-70km) versus a thick (100-160) lithosphere?&lt;/p&gt;&#xA;" OwnerUserId="13182" LastEditorUserId="595" LastEditDate="2018-06-19T12:06:26.247" LastActivityDate="2018-06-19T12:06:26.247" Title="Why does the lithosphere thickness vary within a short distance?" Tags="|geophysics|plate-tectonics|isostasy|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14453" PostTypeId="2" ParentId="14450" CreationDate="2018-06-18T09:45:17.683" Score="6" Body="&lt;p&gt;The cited paper, and ones like it, are young earth creationist nonsense. The Geoscience Research Institute is an arm of the Seventh Day Adventists, whose official position is that &lt;a href=&quot;https://www.adventist.org/en/beliefs/humanity/creation/&quot; rel=&quot;noreferrer&quot;&gt;&quot;in a recent six-day creation the Lord made “the heavens and the earth, the sea, and all that is in them” and rested on the seventh day.&quot;&lt;/a&gt; This is a central tenet of Seventh Day Adventism (it's in the very name of the religion); teaching or writing about an Earth that is billions of years old is explicitly forbidden.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Young earth creationists are wont to attack radiocarbon dating because it has significant limitations. Samples can be contaminated &lt;em&gt;in situ&lt;/em&gt;, during extraction, during storage, in transportation, and in processing. Contrary to Giem's claim that &quot;the hypothesis that machine background can account for this carbon-14 has been universally rejected by researchers in the field, and for good reason,&quot; several of the papers cited by Giem were scientists trying to assess the machine background and other limitations of their techniques.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, Giem cited Aerts-Bijma &lt;em&gt;et al.&lt;/em&gt; seven times. This paper looked at &quot;AMS sample handling in Groningen.&quot; This lab attempts to perform radiocarbon dating in an automated, assembly line fashion, taking about an hour to perform an analysis. This is fine for archeology studies with budget constraints. The paper by Aerts-Bijma found their approach has limits.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One issue with carbon dating is that the previous run can contaminate the next. To test this, Aerts-Bijma &lt;em&gt;et al.&lt;/em&gt; ran two sets of tests against the same sample of anthracite. In one, they interspersed each measurement by carbon dating 100% modern carbon. This gave an artificially high carbon-14 reading for the anthracite. In the other, they didn't do such a dumb thing and found a lower floor. Giem reported the intentionally mishandled reading.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other labs have lower floors by following more stringent but significantly more expensive procedures. Carbon compound scintillators such as those used to detect neutrinos need carbon that has extremely low amounts of carbon-14. The best source of such carbon is old hydrocarbons that have not suffered &lt;em&gt;in situ&lt;/em&gt; contamination. Techniques have been developed to measure carbon-14 to one part per 10&lt;sup&gt;18&lt;/sup&gt; to ensure that those sources are indeed old and uncontaminated. These techniques are well beyond the budget of a typical archeological study. Giem did not report these because they go against his claims.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-06-18T09:45:17.683" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14454" PostTypeId="2" ParentId="14451" CreationDate="2018-06-18T11:04:01.960" Score="6" Body="&lt;p&gt;Note: All of the links in this answer point to various parts of Les Cowley's excellent &lt;a href=&quot;https://www.atoptics.co.uk&quot; rel=&quot;noreferrer&quot;&gt;Atmospheric Optics&lt;/a&gt; site. Les combines photographs, simulated images, and descriptions of the underlying physics to beautifully portray and explain a number of different optical effects in our atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: The imagery on that site is copyrighted. Please do not edit this answer to portray images from that site.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;That's a very nice picture that shows a number of &lt;a href=&quot;https://www.atoptics.co.uk/halosim.htm&quot; rel=&quot;noreferrer&quot;&gt;ice halos&lt;/a&gt;. Ice crystal halos are caused by various shapes of ice crystals. Some of these halos such as the small circle that encircles the Sun in the image in the question are easily seen at all latitudes. Others only appear in very high latitudes, and even there they are rather infrequent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The small circle is the &lt;a href=&quot;https://www.atoptics.co.uk/halo/circular.htm&quot; rel=&quot;noreferrer&quot;&gt;22° halo&lt;/a&gt;. This is a frequently seen halo, much more common than rainbows. It's caused by poorly aligned hexagonal prism ice crystals. If you look closely, you'll see that the sky is darker inside the 22° halo. This is similar to how the sky is darker outside the primary bow of a rainbow. Unlike a rainbow, the color separation is very small, making the 22° halo white rather than colored. If you look closely, you can see that the inner edge has a bit of a reddish tinge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The two bright spots on the sides of the 22° halo are &lt;a href=&quot;https://www.atoptics.co.uk/halo/parhelia.htm&quot; rel=&quot;noreferrer&quot;&gt;sun dogs&lt;/a&gt;. These result from hexagonal plates of ice with their large faces nearly horizontal. The curve the intersects the Sun, runs parallel to the horizon, and intersects the 22° halo at the sun dogs is the &lt;a href=&quot;https://www.atoptics.co.uk/halo/pclow.htm&quot; rel=&quot;noreferrer&quot;&gt;parhelic circle&lt;/a&gt;. Parhelic circles result from sunlight reflecting off nearly vertical faces of ice crystals. The mustache atop the 22° halo is the &lt;a href=&quot;https://www.atoptics.co.uk/halo/column.htm&quot; rel=&quot;noreferrer&quot;&gt;upper tangent arc&lt;/a&gt;. Tangent arcs result from ice crystals that form hexagonal columns rather than hexagonal plates. As is the case with the 22° halo, sun dogs, parhelic circles, and tangent arcs are fairly common.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The partial circle outside the 22° halo is the not so common &lt;a href=&quot;https://www.atoptics.co.uk/halo/supinf.htm&quot; rel=&quot;noreferrer&quot;&gt;supralateral arc&lt;/a&gt;, or possibly the even rarer &lt;a href=&quot;https://www.atoptics.co.uk/halo/46hal.htm&quot; rel=&quot;noreferrer&quot;&gt;46° halo&lt;/a&gt;. Atop that is the &lt;a href=&quot;https://www.atoptics.co.uk/halo/cza.htm&quot; rel=&quot;noreferrer&quot;&gt;circumzenithal arc&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-06-18T11:04:01.960" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14457" PostTypeId="1" CreationDate="2018-06-19T03:36:49.927" Score="2" ViewCount="433" Body="&lt;p&gt;Apologies for what may be a very basic question, but I am struggling to understand the definition of overbank flow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Overbank flow is defined along the lines of this: &lt;a href=&quot;https://definedterm.com/overbank_flow&quot; rel=&quot;nofollow noreferrer&quot;&gt;Water flow over the top of the bankfull channel onto the floodplain.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does this flow include the flow that is in the channel? or is it only the flow that is over the channel?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am working through a document that seems to say one thing with the words, and a different thing with the mathematics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If Qf = overbank flow; Qb = bankfull flow:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the total flow = Qf, where Qf &gt;= Qb &#xA;so if Qf = Qb all flow is in the channel&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or, is total flow = Qf + Qb, flow in channel plus flow out of channel?&lt;/p&gt;&#xA;" OwnerUserId="13185" LastEditorUserId="10681" LastEditDate="2018-08-29T02:39:53.773" LastActivityDate="2018-08-29T02:39:53.773" Title="Clarification of overbank flows" Tags="|hydrology|rivers|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14458" PostTypeId="2" ParentId="14457" CreationDate="2018-06-19T03:43:15.190" Score="2" Body="&lt;p&gt;&lt;em&gt;Overbank flows&lt;/em&gt; means flows that are greater than the channel can handle. Thus the water flow goes over the (river/stream) banks and onto the flood plain. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Bankfull flow&lt;/em&gt; would be the maximum water flow that the channel could contain. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that flow in the channel isn't necessarily the bankfull flow. Of course if there is overbank flow then there must be bankfull flow. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;total flow = Flow in channel + Overbank flow&lt;/p&gt;&#xA;" OwnerUserId="4685" LastEditorUserId="4685" LastEditDate="2018-06-19T04:37:24.473" LastActivityDate="2018-06-19T04:37:24.473" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14459" PostTypeId="1" CreationDate="2018-06-19T06:44:14.833" Score="4" ViewCount="1092" Body="&lt;p&gt;Sand is granular in nature, which allows air columns to trap in between them. As we know that air is an insulator of heat. So here are my questions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does sand maintain its temperatures close to its surface? (Like a conducting shell distributes charge on its surface)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If there were layers of sand, is it possible that in the deeper layers the temperatures remain constant? And only the temperatures of the upper layers changes as the surrounding environment changes?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;P.S. If all of this is true is there a particular formula or a study I can use to figure out the temperature difference between the surface and at a depth in a desert?&lt;/p&gt;&#xA;" OwnerUserId="13186" LastActivityDate="2018-06-19T12:27:31.030" Title="Temperature differences in sand" Tags="|geophysics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14460" PostTypeId="2" ParentId="12502" CreationDate="2018-06-19T12:06:25.220" Score="5" Body="&lt;p&gt;I run an argon lab which does also K-Ar measurements. &#xA;The sample amount depends on the age because you need enough signal strength to measure the radiogenic argon component precisely. Young rocks have very low 40Ar* and to get enough volts on the detector you need more sample. Having the incorrect amount is akin to trying to measure micrometers with a yardstick.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For K measurements 30 mg in our lab is routine.&#xA;For the argon measurement we usually use about 2 mg; for very young rocks up to 200mg for rocks with ca. 2% K. We can date volcanic rocks of less than 20000 years using this technique and have dated historic eruptions successfully in our lab.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Usually customers can say if the rocks are very young, so I usually prepare the sample amount accordingly. I had a couple of completely blind samples where I had no idea of the age of the sample a priori, I ran a test with a ca 4 mg which yielded almost no gas, so I re-ran with more material. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding sampling technique itself- look for minerals with more potassium, such as muscovite, biotite, amphiboles, or more felsic rocks. If the rocks are obviously weathered, they are not suitable. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also have to say that Ar/Ar is a more accurate tool for most rocks and minerals, and then just a few mg is enough if the samples are Mesozoic or older. If they are very young, higher sample amounts are required as with the K-Ar technique.&lt;/p&gt;&#xA;" OwnerUserId="4783" LastActivityDate="2018-06-19T12:06:25.220" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14461" PostTypeId="2" ParentId="14459" CreationDate="2018-06-19T12:27:31.030" Score="4" Body="&lt;p&gt;Yes sand is, on average, quite insulative with the temperature at the surface being rather higher than that at depth when the surface is being actively heated, as by sunlight. The actual degree of insulation depends on at least three factors;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Moisture content, wetter sand is less insulative than dry sand because the water in it's pore spaces conducts heat better than air filled pores would.&lt;/li&gt;&#xA;&lt;li&gt;Average grain size, courser sand has more pore spaces and thus more of it's total volume is made of air so it's more insulative at a given water content.&lt;/li&gt;&#xA;&lt;li&gt;Grain size distribution and sorting, sand composed of grains that are all of a similar size will have more pore spaces than sand composed of many sizes of grain. Grains of the same size act like stacked ball-bearings leaving a lot of empty spaces but with larger and smaller grains the pores between the large grains are filled by the small ones leaving little space for insulative air pockets.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Due to the complexity of the processes involved it is very difficult to have any single formula that gives you a measure of sand in general. You may be able to find, or create, data sets that allow you to predict the insulative value and thus temperature at depth of a particular sand under a particular set of circumstances. Generally speaking it's easier to take field measurements, unless there's a really long-term project involved.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-06-19T12:27:31.030" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14463" PostTypeId="2" ParentId="5047" CreationDate="2018-06-19T23:24:26.233" Score="3" Body="&lt;p&gt;No, it doesn't start raining as soon as relative humidity (RH) is 100%. Clouds form at RH &gt;100%, but this doesn't cause rain. It is mistaken to say that clouds form at 100% RH, since relative humidity at 100% means that water vapor is condensing at the same rate water is evaporating. Thus a cloud at 100% RH will stay a cloud, but a cloud at RH &gt;100% will grow. This is called supersaturation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll generalize the question to &quot;What determines the rate of rainfall?&quot; This implicitly answers your question. Therefore, the point/curve where the rate of rainfall is greater than 0 may provide the answer you seek.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The process of converting cloud to rain is known as autoconversion, and it is still a mysterious process. However, there are various studies that provide empirical relationships, many of which give radically different answers. For example, &lt;a href=&quot;https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/qj.49712454804&quot; rel=&quot;nofollow noreferrer&quot;&gt;one relationship&lt;/a&gt; is $$P_{AUTO}= max(k_1\times(q_c-q_{c,threshold}),0)$$&#xA;where $P_{AUTO}$ is the autoconversion rate in units kg s$^{-1}$, $q_c$ is the cloud water (not water vapor) &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Mixing_ratio&quot; rel=&quot;nofollow noreferrer&quot;&gt;mixing ratio&lt;/a&gt;, $q_{c, threshold}$ is a threshold value approximately 0.0005 kg kg$^{-1}$, and $k_1$ is a conversion rate approximately 0.001 s$^{-1}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These relationships can get very complicated. For example, &lt;a href=&quot;https://journals.ametsoc.org/doi/10.1175/1520-0450%281980%29019%3C1037%3AANIOSF%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tripoli and Cotton&lt;/a&gt; created a relationship $$P_{AUTO}=\frac{0.104gE_{eR}\rho_0^{4/3}}{\mu(N_c \rho_w)^{1/3}}q_c^{7/3}h(q_c-q_{c,threshold})$$ If you are interested in what all of these constants are, I suggest reading the paper. There are a couple more relationships too; they just take some digging to find. I found these relationships in a book called &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/0521126762&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;Parameterization Schemes: Keys to understanding numerical weather prediction models.&quot;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2018-06-20T12:33:12.433" LastActivityDate="2018-06-20T12:33:12.433" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14464" PostTypeId="2" ParentId="14414" CreationDate="2018-06-20T08:01:16.603" Score="2" Body="&lt;p&gt;Time, Frequency, Wavelength and Wavenumber are very closely tied to each other.&lt;/p&gt;&#xA;&lt;p&gt;Our wavelength lambda is directly tied to the frequency f and the velocity v within the rock. Lambda and f are properties of the wave.  v is a rock property. The equation is lambda = v / f. So in the sense of &amp;quot;dependence&amp;quot; everything depending on lambda equally depends on frequency. It's just the inverse after all.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\lambda = \frac{v}{f} = \frac{velocity}{frequency} = wavelength$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Let's build some intuition here. Seeing there is no other place, the dispersion is crammed into v all the way. Take an average sandstone with some average pores. We can send waves at a lot of wavelengths through. Imagine a wave that has a wavelength just barely below the size of the pores (ca. 1mm). That wave will &amp;quot;see&amp;quot; a very different rock than a wave with the wavelength of around 1cm. That wavelength will see a very different rock than a wave at 1m that will not see any of the pores. This wave will probably even average over several heterogeneous rock layers. This phenomenon is called apparent dispersion.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/u0VO2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/u0VO2.jpg&quot; alt=&quot;https://www.ogj.com/articles/print/volume-111/issue-6/exploration---development/useful-data-lurk-in-seismic-inelasticity.html&quot; /&gt;&lt;/a&gt;&#xA;This is taken from &lt;a href=&quot;https://www.ogj.com/articles/print/volume-111/issue-6/exploration---development/useful-data-lurk-in-seismic-inelasticity.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, the rock matrix itself has dispersive properties, which is a fancy way of saying that some waves have it easier travelling through the rock itself. And now we're getting into the fun part of physics. The part where we have to leave the &amp;quot;easy physics&amp;quot;. We always assume seismic waves make infinitesimal (small) elastic changes when travelling through rock. For seismic dispersion, it doesn't work anymore. We have to consider anelastic behaviour there. It also leads us to anisotropy. And lastly, it's tied with seismic attenuation.&lt;/p&gt;&#xA;&lt;p&gt;Let's stay with anelasticity for this answer. Basically, this means that some deformation is irreversible. Larger frequencies and therefore, smaller wavelengths are more prone to dispersion in the Earth. Most mechanical waves are transported via frictional interfaces at the grain. Well cemented rock behaves more &amp;quot;elastic&amp;quot; than loose layers. The transfer of small wavelengths is more similar to long wavelengths when the rock is responding similarly on all size scales. That is the case for cementation, as the stiffened grains behave more like the stiff layers they are a part of. If grains transfer small wavelengths just via friction, the larger wavelength behaves very differently, as most of the large-scale geology isn't too dependent on friction to hold rocks together.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kdq6e.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kdq6e.jpg&quot; alt=&quot;Light Prism&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The easiest analogue is the prism. You shine a white light at a prism and get the colours to separate. This is due to wavelength-dependent (or frequency-dependent) refraction of the incoming wave. The white light is split into all the wavelengths in the prism, giving the separation of colour. You can observe the same happening for seismic data. Instead of a nice focused &amp;quot;seismic beam&amp;quot;, the beam is dispersed along the receiver surface according to its wavelength, just like the prism.&lt;/p&gt;&#xA;&lt;p&gt;Check out Dr Chris Liner's excellent investigation into seismic dispersion:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://seismosblog.blogspot.com/2009/09/seismic-dispersion.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seismos: Seismic dispersion&lt;/a&gt;&lt;br/&gt;&#xA;&lt;a href=&quot;http://seismosblog.blogspot.com/2009/09/dispersion-and-acquisition.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seismos: Dispersion and acquisition&lt;/a&gt;&lt;br/&gt;&#xA;&lt;a href=&quot;http://seismosblog.blogspot.com/2009/09/dispersion-and-processing-near-surface.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seismos: Dispersion and Processing: Near Surface&lt;/a&gt;&lt;br/&gt;&#xA;&lt;a href=&quot;http://seismosblog.blogspot.com/2009/09/dispersion-and-processing-attenuation.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seismos: Dispersion and Processing: Attenuation and Anisotropy&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="507" LastEditorUserId="18088" LastEditDate="2022-12-21T01:38:47.197" LastActivityDate="2022-12-21T01:38:47.197" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14467" PostTypeId="1" CreationDate="2018-06-20T15:35:34.990" Score="2" ViewCount="110" Body="&lt;p&gt;I'm looking for free software for marine surveying, such as &lt;a href=&quot;http://www.ahay.org/wiki/Main_Page&quot; rel=&quot;nofollow noreferrer&quot;&gt;Madagascar&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Seismic_Unix&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seismic Unix&lt;/a&gt;, but preferably with a graphical user interface &lt;/p&gt;&#xA;" OwnerUserId="13192" LastEditorUserId="6298" LastEditDate="2018-06-20T16:34:31.827" LastActivityDate="2018-06-20T16:34:31.827" Title="Free geophysical software with GUI" Tags="|geophysics|software|" AnswerCount="0" CommentCount="2" ClosedDate="2018-06-24T13:08:16.637" ContentLicense="CC BY-SA 4.0" />
  <row Id="14470" PostTypeId="1" CreationDate="2018-06-21T21:00:37.900" Score="0" ViewCount="120" Body="&lt;p&gt;I have daily spatiotemporal  data with covariates at 10 different locations. My question is &lt;strong&gt;&lt;em&gt;is it possible to convert my data&lt;/em&gt;&lt;/strong&gt; into a grid format? &lt;/p&gt;&#xA;" OwnerUserId="13200" LastEditorUserId="2470" LastEditDate="2018-06-22T09:36:54.230" LastActivityDate="2018-06-22T21:48:14.283" Title="Creating regular grid for my data?" Tags="|temperature|climate-models|earth-system|geospatial|grid-spacing|" AnswerCount="1" CommentCount="3" ClosedDate="2018-06-23T08:21:52.293" ContentLicense="CC BY-SA 4.0" />
  <row Id="14472" PostTypeId="1" CreationDate="2018-06-22T03:59:23.693" Score="2" ViewCount="646" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/KQL9g.jpg&quot; alt=&quot;possible fossilized shark tooth&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WBNq3.jpg&quot; alt=&quot;tooth? &quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HlB3o.jpg&quot; alt=&quot;different angle&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/B9WQc.jpg&quot; alt=&quot;please help me identify&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please help me identify this tooth and the era its from. I found it in Panama City Beach Florida. Its cold and hard when i bite it. It looks very old. Possibly a shark tooth? &lt;/p&gt;&#xA;" OwnerUserId="13204" LastEditorUserId="13204" LastEditDate="2018-06-22T04:22:05.907" LastActivityDate="2019-05-29T09:48:48.773" Title="What kind of tooth is this?" Tags="|ocean|fossils|" AnswerCount="1" CommentCount="8" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14473" PostTypeId="2" ParentId="14470" CreationDate="2018-06-22T21:48:14.283" Score="1" Body="&lt;p&gt;Yes, but it will not be a very good dataset. You will only be limited to the size of the dataset.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can use Python's &lt;a href=&quot;https://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.griddata.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;griddata function&lt;/a&gt;. But of course, you will need to make your grid before using the function. Or you can use the &lt;a href=&quot;https://docs.scipy.org/doc/scipy/reference/generated/scipy.interpolate.interp2d.html#scipy.interpolate.interp2d&quot; rel=&quot;nofollow noreferrer&quot;&gt;interp2d function&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2018-06-22T21:48:14.283" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14475" PostTypeId="1" CreationDate="2018-06-23T23:11:43.620" Score="1" ViewCount="59" Body="&lt;p&gt;What is it? It has what looks like white glitter its ugly dark brown and some orange heavy..&lt;img src=&quot;https://i.stack.imgur.com/UQl5K.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="13209" LastEditorUserId="13209" LastEditDate="2018-06-23T23:42:59.193" LastActivityDate="2018-06-23T23:42:59.193" Title="Please help me with the identification of this rock" Tags="|minerals|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14476" PostTypeId="1" AcceptedAnswerId="14502" CreationDate="2018-06-24T00:32:18.440" Score="3" ViewCount="4808" Body="&lt;p&gt;Recently, I've been studying the subject of polymorphism and met two important concepts, the monotropic and enantiotropic polymorphic transition types. However, I can't really seem to grasp the difference between them practically.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I do understand is that enantiotropic polymorphism is reversible, but what does &quot;reversible&quot; mean practically?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, the definition for monotropic polymorphism says that it is irreversible due to metastability. But what exactly is metastability, what does it mean practically? Also, what does &quot;irreversible&quot; mean? Because, surely, I can transform diamond into graphite and graphite into diamond despite it being a monotropic polymorphism.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks in advance for any insight given!&lt;/p&gt;&#xA;" OwnerUserId="13211" LastActivityDate="2020-09-08T22:01:45.793" Title="What exactly are enantiotropic and monotropic polymorphic transitions?" Tags="|geophysics|geochemistry|mineralogy|crystallography|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14478" PostTypeId="1" CreationDate="2018-06-24T08:39:17.930" Score="1" ViewCount="80" Body="&lt;p&gt;I'm using an &lt;a href=&quot;https://imgur.com/sXAWttY&quot; rel=&quot;nofollow noreferrer&quot;&gt;inexpensive seismometer&lt;/a&gt; to try and measure the effects of local HGV traffic on buildings. The device is connected to a Raspberry PI that has a &lt;a href=&quot;https://www.tring-web-design.co.uk/wp-content/uploads/2016/07/DSC_0002-848x450.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cirrus Logic Audio Card&lt;/a&gt;. The signal is fed through the Line In. I am saving the readings from the device as a WAV audio file via arecord:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;arecord -c 1 -f S16_LE -r 11025 --max-file-time 86400 --use-strftime %Y-%m-%d_%H:%M:%S.wav&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://imgur.com/s1Qi1g9&quot; rel=&quot;nofollow noreferrer&quot;&gt;It works&lt;/a&gt;, I can normalize the WAV file in Audacity and see the waveform change as a HGV drives past. After reading a few articles about other experiments doing the same I see that I need to convert the readings from the device into peak particle velocity (PPV) and VDV (Vibration Dose Value) for any of it to make sense in terms of ISO/BS standards (BS7385 &amp;amp; BS5228-2 for example) and assessing the likely effect on a structure of local traffic vibrations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's where I get unstuck, how to convert the data I have into PPV / VDV? I don't know about a few things, like whether the the arecord sampling frequency and depth are correct, I probably shouldn't be normalizing waveforms in Audacity (i'm only doing that so I can see if it's working). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do know that I am looking for frequencies between 15 and 150Hz and that my experiment isn't exactly scientific from the Lego Seismometer, a starting point for possible future more detailed data collection and analysis is all that I need. &lt;/p&gt;&#xA;" OwnerUserId="13212" LastEditorUserId="13212" LastEditDate="2018-06-24T12:17:58.047" LastActivityDate="2018-06-24T12:17:58.047" Title="Seismology - PPV / VDV from geophone waveform data" Tags="|earthquakes|seismology|seismic|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14479" PostTypeId="1" CreationDate="2018-06-24T19:57:12.897" Score="3" ViewCount="1144" Body="&lt;p&gt;I know that refrigerated air just moves heat around, and creates more by using fossil fuel energy in the process.  If we wanted to actually reduce the amount of net heat energy in an area on the planet, and not just move it around, how?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How does the Earth do it?  Is it all in radiating infrared back up through the atmosphere?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can we humans help with this in a way that doesn't just need more carbon based energy?  Can we have thermoelectric (Seebeck) generators powering infrared spotlights pointing out into space or something?&lt;/p&gt;&#xA;" OwnerUserId="13215" LastEditorUserId="39" LastEditDate="2018-06-25T09:23:12.700" LastActivityDate="2024-01-24T14:55:02.220" Title="what is the best way to actually make the Earth lose heat?" Tags="|atmosphere|geophysics|thermodynamics|geoengineering|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14480" PostTypeId="1" CreationDate="2018-06-25T06:09:12.353" Score="1" ViewCount="736" Body="&lt;p&gt;Obviously with a given mass and volume of air, pressure is directly proportional to temperature. However, I would expect the total mass of air within a column of atmosphere to vary over time, due to atmospheric waves (and oceanic waves, over the ocean).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How highly correlated is surface air pressure with surface temperature, at a given site? How much does the variation of atmospheric mass affect that relationship?&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2019-04-05T16:38:52.167" Title="How closely related is surface air temperature to pressure?" Tags="|atmosphere|temperature|barometric-pressure|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14481" PostTypeId="2" ParentId="14479" CreationDate="2018-06-25T09:22:40.583" Score="4" Body="&lt;p&gt;On earth, heat can leave an object through conduction, convection or radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In space, conduction and convection do not work because there is insufficient matter. So the only way for heat to leave the Earth as a whole is by radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This works; the planet loses a lot of heat by radiation. However, at the moment we lose slightly less than we gain, hence global warming. You are correct that the only means of losing heat from the system is radiating it (as infra-red, because that's the wavelength that corresponds to the temperature of the earth's surface). However, while the surface of the planet radiates infra-red, greenhouse gases reflect or absorb a portion of it, reducing the amount that escapes the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So one way to help the planet to radiate heat is to reduce the concentration of greenhouse gases in the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;More direct ways are tricky. My instinct is that things like setting up infrared spotlights pointing up would probably lead to producing more heat on earth than they get rid of, but I'm not totally sure of this - I don't see a &lt;em&gt;fundamental&lt;/em&gt; reason that it couldn't work[1], if they could be made efficient enough; but I don't know whether that level of efficiency is remotely plausible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1] I don't see a conflict with the 2nd law; it's potentially a &quot;moving heat around&quot; mechanism that increases total entropy, but decreases that on earth.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2018-06-25T09:22:40.583" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14484" PostTypeId="2" ParentId="14479" CreationDate="2018-06-25T11:35:10.987" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;What is the best way to actually make the Earth lose heat?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;TL;DR: Stop pumping so much carbon dioxide into the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The easiest approach in terms of human effort would be to let the Earth warm up a tiny bit. Thanks to the Stefan-Boltzmann law, a tiny increase in the Earth's effective temperature will easily rectify the ~0.6 watts/meter&lt;sup&gt;2&lt;/sup&gt; imbalance in the Earth's energy budget. If the Earth was a perfect black body radiating at an effective temperature of 252 kelvins, all that would be needed would be a 0.17° Celsius increase in the effective temperature to make that energy imbalance disappear. Easy, right?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wrong.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks to feedbacks, that small increase in the Earth's effective temperature requires a significantly larger increase in the Earth's surface temperature, and that's ignoring the fact that humanity is currently making the energy imbalance worse. Temperatures are currently rising and will continue to rise for a while due to the large amount of CO&lt;sub&gt;2&lt;/sub&gt; humanity has already pumped into the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Continuing to pump ever increasing amounts of CO&lt;sub&gt;2&lt;/sub&gt; into the atmosphere (the &quot;business as usual&quot; scenario) will result in a 4° to 9° C increase in the Earth's surface temperature by the end of the century, with the uncertainty of the increase depending largely on the climate sensitivity to a doubling in CO&lt;sub&gt;2&lt;/sub&gt; levels. Even the bottom of that range represents a disaster. The only way to avoid this disaster is to stop pumping so much CO&lt;sub&gt;2&lt;/sub&gt; into the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Can we have thermoelectric (Seebeck) generators powering infrared spotlights pointing out into space or something?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You wouldn't want to use infrared spotlights. You'd want the radiation to be in the visible range. The atmosphere is opaque in the infrared.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Playing &quot;what if&quot;, suppose every last bit of energy currently consumed by humanity (18 terawatts) is used to power massive air conditioners, with lasers venting the generated heat into space. Suppose we somehow manage to get 17 times as much cooling as energy consumed out of the system, resulting in 300 terawatts of cooling. Dividing that by the Earth's surface area results in 0.6 watts per square meter -- i.e., the current energy imbalance. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is of course utterly unrealistic.  We aren't plowing or harvesting our fields, manufacturing products, transporting goods, driving to and from work, heating or cooling our houses. To make this unrealistic &quot;what-if&quot; scenario worse, the hydrocarbons used to produce that energy are exacerbating the energy imbalance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The best way to make the Earth lose heat is to stop pumping so much carbon dioxide into the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-06-25T11:35:10.987" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14487" PostTypeId="2" ParentId="14480" CreationDate="2018-06-25T13:12:24.587" Score="4" Body="&lt;p&gt;You have opened a very large can of worms.  You will need a larger can to get them all together again.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem is time lag.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's do some thought experiments:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's dawn in the desert.  Right now the bottom of the atmosphere is cool.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sun heats the dirt, and the dirt heats the air.  Air expands some.  But the air above it is lazy about getting out of the way.  So the air pressure goes up some.  Air finally shoves that air above up, and then whether the pressure goes up or down depends on how fast it can get out of the way.  Small area -- parking lot, the air spills in all directions.  adjusts quickly.  Gobi desert air starts to push out sideways, Coriolis rears up, and you have a temporary high pressure.  At night the reverse happens.  Ground cools, air shrinks, but the air around it doesn't fill in right away.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lets look at longer term features.  Consider the Alaska low.  The north pacific is warm, at least by ocean standards, and so the air above it is warm.  Warmer air is less dense, and since the low stays more or less put for months at a time, the entire air column is warmish.  Warm air is less dense than the cooler air around it. It has a lower effective surface pressure than cooler air around it. The cooler air from around it tries to rush in, but... Coriolis again. Friction restricts how much of that air can enter the low area. Low pressure warm air is pushed out by moving upward as a series of cloud and rainy weather.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We think of the atmosphere in our heads as this thick blanket covering the earth.  But most of the interesting stuff is in the bottom 3/4 of the atmosphere (by mass) which is about 36,000 feet. Call it 5 miles. It's a thin apple skin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the messy bits is the scale problem:  There is very little change in energy moving a parcel horizontally.  But moving it vertically gets messy.  Pressure changes.  Temperature changes.  Water condenses/evaporates adding/removing sensible heat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the eye openers for me was realizing that in a lot of physics, you can analyze and quickly conclude that certain forces have small effects and can be ignored.  In atmospheric dynamics I find myself unable to figure out what can be ignored, or left with a first level approximation.  Everything affects everything else. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyway to answer your question:  Warming temperatures will initially increase pressure, but later decrease pressure.  Cooling temperatures the opposite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looking at Edmonton, AB's forecast for the next 10 days, we are getting daily temp fluctuations of about 11 C, and daily pressure variations of about 4 hPa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the gas laws this is an 11 K compared to about 300 K so the pressure should change by about 11/300 of it's absolute pressure.  This would be about 37 hPa.  Why doesn't it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because it's not the whole air column that's changing temp.  Typically only about the bottom 3000 feet changes on a daily basis -- daytime mixing depth, with some mixing higher up.  3000 feet has about 1/10 of the atmosphere in it so the variation is only about a tenth.  Ok, that gives 3.7 hpa.  Closer to 4, but still off.  Remember you ignore factors at your peril in atmospheric.  &lt;/p&gt;&#xA;" OwnerUserId="13145" LastEditorUserId="13534" LastEditDate="2019-04-05T16:38:52.167" LastActivityDate="2019-04-05T16:38:52.167" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14488" PostTypeId="1" AcceptedAnswerId="14505" CreationDate="2018-06-25T14:32:22.900" Score="2" ViewCount="997" Body="&lt;p&gt;My understanding is that low pressure is usually associated with cloudy skies, however in the last week I observed a day that had low pressure reading but no clouds. Is this possible or did I perhaps read the barometer wrong?&lt;/p&gt;&#xA;" OwnerUserId="13225" LastActivityDate="2018-06-26T22:06:45.847" Title="Can you have a low pressure with no clouds?" Tags="|meteorology|weather-forecasting|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14489" PostTypeId="1" AcceptedAnswerId="15089" CreationDate="2018-06-25T15:36:05.100" Score="10" ViewCount="1510" Body="&lt;p&gt;CO&lt;sub&gt;2&lt;/sub&gt; levels are increasing, they have crossed 400 ppm, which means that of every million gas molecules in the air, 400 are of CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&lt;p&gt;It has been increasing. Does that mean the total volume of air in the atmosphere is increasing or that some other gas is decreasing as CO&lt;sub&gt;2&lt;/sub&gt; increases?&lt;/p&gt;&#xA;" OwnerUserId="11519" LastEditorUserId="2470" LastEditDate="2021-11-01T17:24:31.403" LastActivityDate="2021-11-15T23:39:34.527" Title="Is volume of air increasing as CO2 levels increase?" Tags="|atmosphere|climate-change|co2|air|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="14490" PostTypeId="2" ParentId="14488" CreationDate="2018-06-25T15:52:50.890" Score="1" Body="&lt;p&gt;I'm not an expert, but my understanding is that you need moisture/humidity &lt;strong&gt;and&lt;/strong&gt;  nuclei around which water droplets can form. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I remember seeing a demonstration many years ago that showed this. There was a box about 12&quot; per side with one side a rubber sheet and a few sides glass or plastic. They pulled the rubber sheet out (lowering the pressure) and nothing. They then lit and blew out a match inside the chamber. Closed the door, pulled the rubber sheet, viola a little cloud.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The soot provided the nuclei for the water droplets. &lt;/p&gt;&#xA;" OwnerUserId="10936" LastActivityDate="2018-06-25T15:52:50.890" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14491" PostTypeId="1" AcceptedAnswerId="14525" CreationDate="2018-06-25T16:23:45.480" Score="6" ViewCount="3404" Body="&lt;p&gt;The solar radiation is one of the important factors controlling the formation of $O_3$, and thereby impacting the levels of various secondary species in the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, in the campaign of ambient $PM_{2.5}$ sampling, I don't have the instrument to acquire the actual solar radiation data. Since the solar radiation can be calculated mainly by the altitude degree of the sun, I turned to find a way to calculate the ideal values in clean sky condition.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found that &lt;a href=&quot;http://docs.pysolar.org/en/latest/#examples&quot; rel=&quot;noreferrer&quot;&gt;pysolar&lt;/a&gt; is a potential tool to tackle this kind of issue.  By simply defining the location(Lon, Lat), and the date time, the solar radiation in the unit of $W/m^2$ can be generated. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;However, the output result here seems to be strange. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Here is an example using Python 3.4:    &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;# Noted that the package can only be implemented in Python 3.4 environment&#xA;from pysolar.solar import *&#xA;import datetime&#xA;&#xA;# define the location (Beijing, China)&#xA;lat, lon = 39.9075, 116.39723&#xA;&#xA;# generate the time series dataset of the solar radiation&#xA;start = datetime.datetime(2018, 1, 1, 8, 0, 0, 0, tzinfo=datetime.timezone.utc)&#xA;&#xA;solar_data = []&#xA;for i in range(0,24*90,1): # 24 hours x 90 days&#xA;    date = start + pd.to_timedelta(1,'H')&#xA;    altitude_deg = get_altitude(lat, lon, date)&#xA;    solar_data.append(radiation.get_radiation_direct(date, altitude_deg))&#xA;&#xA;solar_ = pd.Dataframe([])&#xA;solar_['value] = solar_data&#xA;&#xA;# Plotting&#xA;## Before plotting, I found there are a lot of extreme values with the radiation larger than  10e5. I don't know the reasons why they came up, and how to delete those data by conditions. &#xA;&#xA;solar_.loc[solar_.value&amp;gt;5000, 'value'] = np.nan&#xA;plt.plot(solar_.value)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/C63Xq.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/C63Xq.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The result seems to be incorrect. In my opinion, the solar radiation should present a clear diurnal pattern with seasonal heterogeneity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How to explain the bizarre results? Or is there any better solution for the solar radiation data if the monitoring equipment is unavailable. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any comments or suggestions would be appreciated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;PS&lt;/strong&gt;: I added the result of altitude degree   the same period to response the comment of BarocliniCplusplus &#xA;&lt;a href=&quot;https://i.stack.imgur.com/zxa31.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zxa31.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="5214" LastEditDate="2018-06-29T05:12:08.890" LastActivityDate="2021-03-27T17:03:08.797" Title="How to calculate the solar radiation at any place, any time" Tags="|meteorology|atmosphere|atmosphere-modelling|atmospheric-chemistry|atmospheric-radiation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14492" PostTypeId="1" AcceptedAnswerId="14493" CreationDate="2018-06-25T20:21:15.410" Score="6" ViewCount="4494" Body="&lt;p&gt;Where I live the soil is red.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a map or chart where you can see the average color of the dirt according to geographical location?  What would the color be if all of the dirt on Earth was added equally to a pallet?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand that composition of minerals determines dirt color but what makes dirt its color is not the question I am asking.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kata Tjuta, Northern Territory, Australia&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qEQh9.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qEQh9.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sagada, Mountain Province, Philippines&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qbciQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qbciQ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://eugeneexplorer.wordpress.com/2016/11/22/blue-soil-hills/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://eugeneexplorer.wordpress.com/2016/11/22/blue-soil-hills/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gentry County, Missouri, United States&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xPzeV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xPzeV.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.airphotona.com/image.asp?imageid=11944&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.airphotona.com/image.asp?imageid=11944&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="-1" LastEditDate="2020-10-27T11:11:36.900" LastActivityDate="2020-10-27T11:11:36.900" Title="What is the average color of soil?" Tags="|geology|soil|mapping|regional-geology|" AnswerCount="3" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="14493" PostTypeId="2" ParentId="14492" CreationDate="2018-06-25T21:58:47.283" Score="22" Body="&lt;p&gt;This gif, prepared by the United States Department of Agriculture - Natural Resources Conservation Services (USDA-NRCS) soil scientists at the National Soil Survey Center, has soil colors based on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Munsell_color_system&quot; rel=&quot;noreferrer&quot;&gt;Munsell Color System&lt;/a&gt; for the United States at different depths:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hYB1E.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hYB1E.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The soil colors nearest the surface are darker due to more organic matter and are lighter at depth with varying colors by region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://munsell.com/color-blog/soil-colors-national-parks-anniversary/&quot; rel=&quot;noreferrer&quot;&gt;http://munsell.com/color-blog/soil-colors-national-parks-anniversary/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This link also has soil colors of select United States National Parks.  For example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XudzC.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XudzC.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastEditorDisplayName="user11318" LastEditDate="2018-06-26T01:20:28.370" LastActivityDate="2018-06-26T01:20:28.370" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14495" PostTypeId="2" ParentId="14492" CreationDate="2018-06-26T01:33:28.347" Score="8" Body="&lt;p&gt;Soil color is largely determined by it's composition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are three main components in soil:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Gravel, sand, and silt.  In essence, the type of stuff you find in sedimentary rocks. Usually, this is mostly silicate minerals like quartz, feldspar, and mica, and is usually pretty bland in terms of color.  In theory, certain silt minerals (olivines for example) can produce greenish soils, though concentrations that high are generally uncommon.  With sand involved, you can get lots of other colors (yellow, pink, purple, and even green), though this is usually only seen on beaches.&lt;/li&gt;&#xA;&lt;li&gt;Clay.  Clay's often account for a large percentage of the weight of soil.  They also usually account for many of the color variations.  Most likely, that red soil near where you live has a lot of hematite rich clay in it.  Clay's mostly contribute red, yellow, and brown shades to soil, but can in theory give almost any color.  Brightly colored soils are usually the result of a sesquioxide clay, and can in theory be almost any color (red from iron, blue from copper or cobalt, green from copper, nickel, or chromium, yellow from chromium or iron, purple from manganese, etc), though only iron is particularly common.&lt;/li&gt;&#xA;&lt;li&gt;Humus.  Humus is heavily decomposed organic matter.  It has a rather distinctly dark brown (almost black) color to it, and also accounts for.much of the earthy smell of soil.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Beyond those, there are a few other things that may be in soil and impact the color:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Charcoal. Usually found only in certain climates (warm with lots of humidity, like tropical rainforests), gives a very dark color to the soil.&lt;/li&gt;&#xA;&lt;li&gt;Fungus.  There's &lt;em&gt;a lot&lt;/em&gt; of fungus in soil.  Usually, it's not concentrated enough (or colorful enough) to have an impact, but in places where there is a very high concentration, it can have a localized impact on soil color.&lt;/li&gt;&#xA;&lt;li&gt;Shells.  Either from diatoms (that's what diatomaceous earth is, lots and lots of microscopic shells), or very finely ground shells from bigger organisms.  You've probably seen pictures of pink or salmon colored beaches, the same effect can also happen to a much lesser degree in soil too.  Usually though, lots of shells just turns soil white.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So, what color would that translate to on average?  Well, for topsoil, due to the generally high humus content, probably a rather dark brown.  Averaging over all soil, most likely something significantly lighter, as deeper soil tends to have much lower concentrations of organic matter, but likely still tan or beige.&lt;/p&gt;&#xA;" OwnerUserId="11498" LastEditorUserId="11498" LastEditDate="2018-06-26T20:40:48.497" LastActivityDate="2018-06-26T20:40:48.497" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14497" PostTypeId="1" AcceptedAnswerId="14498" CreationDate="2018-06-26T15:09:58.280" Score="12" ViewCount="1164" Body="&lt;p&gt;Whilst riding on Mam Tor in Castleton, England I came across this scene (not my photo) and I would like to know what causes the formations which I have ringed in red. They &lt;em&gt;look&lt;/em&gt; like piles of earth have been deposited a long time ago, but clearly that can't be the case, so what causes them?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OEbU5.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OEbU5.jpg&quot; alt=&quot;Marked Mounds&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;http://www.derbyshirelife.co.uk/out-about/12-photos-that-capture-the-true-beauty-of-mam-tor-1-4566874&quot; rel=&quot;noreferrer&quot;&gt;Another image of these mounds&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13234" LastEditorDisplayName="user12525" LastEditDate="2019-08-27T11:15:42.453" LastActivityDate="2019-08-27T11:15:42.453" Title="What causes these mound-like ground formations?" Tags="|geomorphology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14498" PostTypeId="2" ParentId="14497" CreationDate="2018-06-26T15:20:34.707" Score="6" Body="&lt;p&gt;They're landslide deposits; &lt;a href=&quot;https://en.wikipedia.org/wiki/Mam_Tor&quot; rel=&quot;noreferrer&quot;&gt;Mam Tor&lt;/a&gt; gets its name, which translates as &quot;mother hill&quot;, from the regular landslides that come off the higher slopes and form hillocks further down into the valley.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-06-26T15:20:34.707" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="14500" PostTypeId="2" ParentId="14497" CreationDate="2018-06-26T16:31:49.507" Score="5" Body="&lt;p&gt;&lt;strong&gt;*edited: actual agreement is they are landslides&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think that forms are &lt;a href=&quot;https://en.wikipedia.org/wiki/Drumlin&quot; rel=&quot;nofollow noreferrer&quot;&gt;drumlins&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The drumlins are elongated hills with their major axis parallel to the&#xA;  direction of ice movement. They have the shape of an inverted spoon or&#xA;  a semi-ellipsoid more or less elongated. Its length ranges between 10&#xA;  and 3,000 meters, the height is between 5 and 50 meters and the width&#xA;  has variable dimensions depending on its degree of elongation. Its&#xA;  longitudinal profile presents a slope of higher slope upstream.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: &lt;a href=&quot;https://www.casadellibro.com/libro-geomorfologia/9788483223895/1197545?gclid=cjwkcajwymfzbraxeiwa-r3gm85lvupblbb345oripvtjm9vfxwtgd7buwfbahe2hofvr4ceeijodhocvp8qavd_bwe&amp;amp;utm_source=google&amp;amp;utm_medium=cpc&amp;amp;utm_campaign=19438&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geomorphology. Gutiérrez Elorza, M. Prentice Hall&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Zone has glaciar/periglaciar geomorphology, wich would match with my sugestion. The morphology of the forms on the picture matches with the description.&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2018-06-27T13:14:09.597" LastActivityDate="2018-06-27T13:14:09.597" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14501" PostTypeId="1" AcceptedAnswerId="14530" CreationDate="2018-06-26T19:14:52.913" Score="3" ViewCount="73" Body="&lt;p&gt;I'm working on a map in GMT and am having trouble finding lon/lat data for the minor plate boundaries (specifically the adriatic). Is there a database I can refer to?&lt;/p&gt;&#xA;" OwnerUserId="11430" LastActivityDate="2018-06-29T17:44:50.030" Title="Plate boundary lon/lat data" Tags="|geophysics|plate-tectonics|geodesy|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14502" PostTypeId="2" ParentId="14476" CreationDate="2018-06-26T19:28:37.250" Score="3" Body="&lt;p&gt;If you can get your hands on a copy of Fegley's book &lt;em&gt;Practical Chemical Thermodynamics for Geoscientists&lt;/em&gt;, he gives a good description in Chapter 07, which I'll summarize here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An &lt;em&gt;enantiotrope&lt;/em&gt; is a polymorph that undergoes a &lt;em&gt;reversible&lt;/em&gt; transformation into another polymorph at &lt;em&gt;atmospheric pressure&lt;/em&gt;. If you're not familiar with the concept of reversibility you may want to read up on entropy, spontaneity, and the 2nd law of thermodynamics. Briefly, a reversible transformation is a process in which the system and surroundings are in equilibrium at all times. An important property of these processes is that $\Delta$ S$_{universe}$=0. Reversible processes don't actually occur in nature but they can make good approximations for some things we observe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A &lt;em&gt;monotrope&lt;/em&gt; is a polymorph that does not have a &lt;em&gt;reversible transformation&lt;/em&gt; into another polymorph at &lt;em&gt;atmospheric pressure&lt;/em&gt;. One polymorph is always stable and the other is metastable. Monotropy exists in systems where the transition temperature between solid polymorphs is above the melting point of the lower-temperature polymorph. In many cases, upon heating the metastable monotrope melts, then resolidifies to the stable monotrope, which melts at a higher temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Metastability refers to a nonequilibrium state that is approaching equilibrium slowly enough that we can say it's stable over a given period of time. &lt;/p&gt;&#xA;" OwnerUserId="11430" LastEditorUserId="11430" LastEditDate="2018-06-26T23:23:23.700" LastActivityDate="2018-06-26T23:23:23.700" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14505" PostTypeId="2" ParentId="14488" CreationDate="2018-06-26T22:06:45.847" Score="4" Body="&lt;p&gt;Low pressure areas are simply areas where the air is less dense than the surrounding areas.  The scale of these differences can be small, size of a small farm field, or large, covering expansive areas of the earth's surface.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clouds form around low pressure systems typically because of the way low pressure systems develop and the air moves around them.  Typically low pressure systems start forming over relatively warmer sections of the earth, this is gross over simplification, as the air warms it becomes less dense and will tend to rise.  This rising of warm often moist air leads to cloud formation because as air rises it also becomes cooler, see &lt;a href=&quot;https://en.wikipedia.org/wiki/Lapse_rate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lapse Rate&lt;/a&gt;.  Typically at some time the temperature drops below the dew point in the air moving upwards and clouds form.  But if the relative humidity of the air is not high it is possible that the air mass in the low pressure system never rises high enough for condensation of the water vapor to occur, in this case no clouds will form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In conclusion it is possible to read a lower air pressure at a site and still not have cloud formation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This site has a good graphic on how low and high pressure systems relate to each other. &lt;a href=&quot;https://content.meteoblue.com/en/meteoscool/large-scale-weather/high-low-pressure&quot; rel=&quot;nofollow noreferrer&quot;&gt;High and Low weather systems described&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please note that I am not meteorologist.  This answer does not consider all the aspects associated with cloud formation such as how airborne particulates can affect condensation&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2018-06-26T22:06:45.847" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14506" PostTypeId="1" AcceptedAnswerId="14507" CreationDate="2018-06-27T16:45:09.477" Score="9" ViewCount="798" Body="&lt;p&gt;The Hawaiian-Emperor seamount chain stretches from Russia to the Hawaiian islands.  When I look at them on a map, it seems that the oldest seamounts by Russia are shorter and smaller than the newer seamounts/islands, and even in the most recent additions (the Hawaiian islands) there seems to be a gradient in size, with the older islands being the smallest and the newest island by far the largest and with the tallest volcanoes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this gradient in size due to erosion?  Were the seamounts at one point islands?  Or is there something related to the volcanic activity and plate motion itself that is producing larger volcanoes more recently?&lt;/p&gt;&#xA;" OwnerUserId="8339" LastActivityDate="2018-07-22T14:00:12.897" Title="Why are the latest additions to the Hawaiian-Emperor seamount chain the highest?" Tags="|volcanology|plate-tectonics|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14507" PostTypeId="2" ParentId="14506" CreationDate="2018-06-27T17:25:05.853" Score="14" Body="&lt;p&gt;As it was explained to me at university there are two factors; buoyancy and erosion. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rock buoyancy is a major factor, fresh Basalt is hot and dry and has a much lower density than older oceanic crust. This is why the mid-Atlantic ridge rises above the surrounding seabed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The effect is even more pronounced with seamounts because they're composed of even hotter rock that takes much longer to cool and wet. As seamounts age they cool, making them denser. As they cool, they absorb water, making them still denser. Where that water interacts with the still cooling rock, secondary mineralisation occurs, which fills gas pockets and other voids, making the rock denser again. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;All of this results in the seamount sinking farther into the crust which reduces it's height above sea-level over, relatively short, geological time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the same time the mounts are sinking they're also being weathered from above. This shortens them, and also disguises the depression in the seabed from the sinking mountain with debris from above, since erosion generally slows as the mounts sink deeper. Also, as they move north out of tropical waters and coral growth stops, they stop growing at all.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The newer mounts are taller only because they're younger, hotter, and drier, they'll sink and shrink as they age.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="6467" LastEditDate="2018-06-27T18:39:59.003" LastActivityDate="2018-06-27T18:39:59.003" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14508" PostTypeId="1" AcceptedAnswerId="14510" CreationDate="2018-06-28T04:48:24.747" Score="3" ViewCount="833" Body="&lt;p&gt;On a trip to Honduras a few years ago I visited one of the islands off its north coast with a friend and went to a section of it mostly with nothing but residences which looked far less visited by tourists and which had no live coral off the coast in that section of island unlike other parts of it. While in that area we saw what looked like a rocky protrusion a little off from a small beach, about 50 or so yards offshore, so my friend and I waded out to it and we were stunned to discover that it was a rather large exposed section of coral that had been completely fossilized. It was pitted in parts, reminding me a bit of the surface of the moon, but we clearly saw amazing varieties of coral and their fossilized contours and patterns in the &amp;quot;rock&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;But more puzzling is that it protruded at its base a good 1-2ft above sea level on average (though erosion made the edges gradually slope down to the water) and up to probably between 5 to 7ft above sea level in some other areas where the coral [or mass it was on] protruded), which made the highest sections clearly higher than the beach we had just waded from. That seemed to indicate that the ocean level may have been quite a bit higher when it was still alive and parts of the island may have been more submerged at some point in the past if I had to guess.&lt;/p&gt;&#xA;&lt;p&gt;Ignoring for a moment my imprecise measurements and notes about its exposure relative to sea-level, how long would it take any portion of alive and healthy coral to fossilize once exposed directly to the sun outside of/above water at its quickest, turning rock-grey and becoming firm, even if the fossilization process is not completed to its utmost extent? Can it happen in a few thousand years, or does it happen only at a significantly slower rate than that? Has any such process of fossilization actually been observed (as proceeding through its stages) at any point throughout recorded human history, and what would intermediate stages look like in terms of color, firmness, etc.?&lt;/p&gt;&#xA;&lt;p&gt;I am not an earth scientist so you'll have to go easy on the explanation here.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt; I have now uploaded some &lt;a href=&quot;https://flic.kr/s/aHsmobvEPV&quot; rel=&quot;nofollow noreferrer&quot;&gt;photos to Flickr&lt;/a&gt; of the particular coral I saw. The &amp;quot;mini island&amp;quot; (I'll call it) was quite alien-looking and bizarre in places, also overgrown with some plants on the main mass, but you can, for example, see the close up I took of one fossilized bit of brain coral that was firmly set in the rock.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WJv56.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WJv56.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I also &lt;a href=&quot;https://www.flickr.com/photos/jsjgeology/15643832613&quot; rel=&quot;nofollow noreferrer&quot;&gt;found a similar photo&lt;/a&gt; on Flicker taken by someone else taken from San Salvador (Bahamas) at what is identified as the Cockburn Town Fossil Reef, and the photo has an interesting scientific essay with citations in the image description.&lt;/p&gt;&#xA;" OwnerUserId="13251" LastEditorUserId="13251" LastEditDate="2023-05-17T22:50:19.000" LastActivityDate="2023-05-17T22:50:19.000" Title="How quickly can coral fossilize?" Tags="|oceanography|fossils|biogeochemistry|geobiology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14510" PostTypeId="2" ParentId="14508" CreationDate="2018-06-28T12:42:26.727" Score="4" Body="&lt;p&gt;First thing is that the sea-level wasn't necessarily that high when the reef was growing, Hondurus is on the edge of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cayman_Trough&quot; rel=&quot;nofollow noreferrer&quot;&gt;Caymen Trough Fault Zone&lt;/a&gt; and experiences quite high rates of uplift, (relatively speaking, your fingernails actually grow faster but over long periods it builds up). So the Coral reefs you're seeing high and dry could be quite recent in geological terms and laid down at or close to current sea levels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Live Coral is a thin skin of either &lt;a href=&quot;https://en.wikipedia.org/wiki/Coralline_algae&quot; rel=&quot;nofollow noreferrer&quot;&gt;algae&lt;/a&gt; or tiny animals called &lt;a href=&quot;https://en.wikipedia.org/wiki/Polyp&quot; rel=&quot;nofollow noreferrer&quot;&gt;polyps&lt;/a&gt; over what is essentially already &lt;a href=&quot;https://en.wikipedia.org/wiki/Limestone&quot; rel=&quot;nofollow noreferrer&quot;&gt;Limestone&lt;/a&gt;. The live coating builds up this Limestone in order to 1. protect itself and 2. gain advantageous position as far as sunlight and nutrient rich currents etc... Once the coral builders die, which can happen within minutes of exposure to the air for some species (for others the water just has to get too warm, or too cold), the &quot;skeleton&quot; is already effectively a fossil and pretty well as hard as it's going to get.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any reef is largely made of Limestone from dead Corals that have either simply been grown over or have been broken, ground down and then the coral sand concreted together because of biological and/or chemical processes to form bulk Limestone in which most or all of the old coralline structure is invisible. The primary mechanism for removing coral structure is actually fish that crush coral chips into sand or even finer grains while feeding on surface dwelling algae. The hardening of these grains into a homogeneous whole is usually a combination of the action of coralline algae creating lime on the grain surfaces that bridges individual grains together and the chemical precipitation of dissolved minerals, particularly &lt;a href=&quot;https://en.wikipedia.org/wiki/Calcium_carbonate&quot; rel=&quot;nofollow noreferrer&quot;&gt;calcium carbonate&lt;/a&gt; from the grains themselves, into the lime sand beds due to daily fluctuations in water temperature and the associated calcium carbonate solubility shift. As the temperature of the water drops at night more lime can and is dissolved into the sea, during the day this process is reversed by the rising water temperature. This process is ongoing with coral sourced lime being added to the limestone reef steadily all the time it's growing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of the grey colouration you've observed a lot of that will be land derived sediment that was incorporated into the reef while it was still growing and is the natural colour I would expect from an exposed reef deposit so close to shore. Some of it may also be surface in nature though and the rate at which that will accumulate will depend on the wind, the amount of dust in the environment and the surface porosity of the exposed deposit. The higher the winds, the dust count, and/or the surface porosity the faster that surface will be discoloured by dust. There might be a little bit of chemical staining from water percolation but that's normally in the form of Iron and is yellow, red, or orange in colour, similar to &lt;a href=&quot;https://en.wikipedia.org/wiki/Iron-rich_sedimentary_rocks#/media/File:IronInRocksMakeRiverRed.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;this image&lt;/a&gt; from Spain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Short version not much has actually happened to the reef deposits you're seeing since they were laid down except that as the land has risen they've been taken along for the ride and are now above sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I missed anything or wasn't clear somewhere along the line give me a shout in the comments and I'll update accordingly.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="10735" LastEditDate="2018-06-28T13:58:58.487" LastActivityDate="2018-06-28T13:58:58.487" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="14511" PostTypeId="1" CreationDate="2018-06-28T15:00:35.793" Score="0" ViewCount="72" Body="&lt;p&gt;This question is inspired by the book &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/0898866871&quot; rel=&quot;nofollow noreferrer&quot;&gt;Minus 148 Degrees&lt;/a&gt;, which is a true story about a group of mountaineers that got stuck at a high elevation on Denali during a storm and survived 6 days in what is described as &quot;-148F with wind chill&quot;. I am told the winds attained speeds in excess of 150mph.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have made a spreadsheet using the modern wind chill formula to make some estimates about the base temperature, but I understand that the way wind chill is estimated has changed over time and would not have been the same when the book was written and originally published in the late 1960's.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What would be the likely candidate(s) method used at that time to estimate the -148F wind chill temperature?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The wind chill calculator &lt;a href=&quot;http://www.onlineconversion.com/windchill.htm&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;wind chill calculator&quot;&gt;here&lt;/a&gt; includes a &quot;pre-2001&quot; formula, but that formula seems broken for the range we are looking at. Putting in a higher speed (ie: going from 150 to 160) produces a &lt;em&gt;warmer&lt;/em&gt; wind-chill, so I don't think we can trust that, so I doubt such a formula would have been used. However, that formula would suggest -122F @ 150mph = -148F wind-chill, which does not seem right - planet record cold in Antarctic winter is only a little colder than that. So I'm skeptical of this &quot;pre-2001 formula&quot; as being the method used to determine the -148F estimate.&lt;/p&gt;&#xA;" OwnerUserId="11171" LastEditorUserId="11171" LastEditDate="2018-06-28T15:11:03.377" LastActivityDate="2018-06-28T15:11:03.377" Title="What method would be used to estimate a wind-chill temperature in U.S. 1969?" Tags="|temperature|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14512" PostTypeId="2" ParentId="14283" CreationDate="2018-06-28T17:09:14.130" Score="1" Body="&lt;p&gt;I would recommend looking at automatic stream network delineation and/or known stream locations features, and overlaying those as a check on the final watersheds created through whatever procedure you have. Watersheds can be merged or lumped together, which is fine, you just want to make sure it is consistent with the other information you have and what your goal is. There will always be some variation in the exact extents of the watersheds depending on what algorithm you use, but you should definitely make sure the general areas and drainage patterns are consistent with what you expect. Beyond that, I am not sure there is a correct answer.&lt;/p&gt;&#xA;" OwnerUserId="8440" LastActivityDate="2018-06-28T17:09:14.130" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14513" PostTypeId="2" ParentId="14249" CreationDate="2018-06-28T17:27:47.353" Score="4" Body="&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The models are similar in that they simplify the rainfall-runoff relationship into a few parameters, and essentially use some kind of first-order coefficient to partition rainfall into infiltration and runoff. The differences are mostly in what other parameters are brought in, such as initial abstraction in the SCS method (i.e. some capture of antecedent moisture conditions). You may wish to pick the method that best captures the information you wish to include in the calculation (or have available), such as drainage area. You can find more details about the implicit assumptiopns and ranges of applicability for each method (e.g. &lt;a href=&quot;http://onlinemanuals.txdot.gov/txdotmanuals/hyd/rational_method.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;rational method&lt;/a&gt;).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;In terms of other methods, there are many methods that use some similar forms of soil moisture, soil saturation, etc. to estimate the rainfall-runoff partition. For example, take a look at the Infiltration section (4.2) of the Raven Hydrologic Modelling Framework &lt;a href=&quot;http://raven.uwaterloo.ca/files/v2.8/RavenManual_v2.8.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;manual v2.8&lt;/a&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;As to whether they are empirical, likely depends who you ask. Empiricism is likely more of a spectrum than a binary system. These are not simply linear regression equations and do capture some physics, although they are still clearly at least partially empirical since the coefficients are basically based on experiments to best fit results. I would likely describe them as empirical or semi-empirical, although I wouldn't spend too much time trying to split hairs for this question.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="8440" LastActivityDate="2018-06-28T17:27:47.353" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14514" PostTypeId="1" AcceptedAnswerId="14529" CreationDate="2018-06-28T18:26:34.533" Score="7" ViewCount="4809" Body="&lt;p&gt;I'm studying meteorology for a pilot license and there I was taught as a rule of thumb that wind at higher altitudes is approximately turned 30° clockwise to the wind on the surface due to the Coriolis Effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The explanation I got is that if an air parcel moves e.g. towards the pole, it started with a higher velocity around the earth's axis than the destination point has, so it will arrive ahead of the destination point on the earth's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While that totally makes sense for winds e.g. from south to north, or the other way round - why does the Coriolis effect also impact a wind that's blowing exactly from East to West? Shouldn't the origin and the destination of that wind have the same speed around earth's axis and therefore no Coriolis force should act on the wind?&lt;/p&gt;&#xA;" OwnerUserId="13255" LastEditorUserId="39" LastEditDate="2018-12-06T10:24:18.050" LastActivityDate="2023-04-27T05:08:24.127" Title="Does the Coriolis Effect affect a wind from East to West?" Tags="|meteorology|geophysics|wind|coriolis|" AnswerCount="5" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14518" PostTypeId="1" CreationDate="2018-06-28T18:58:36.630" Score="1" ViewCount="145" Body="&lt;p&gt;What is the role of spectral whitening in the processing step done before cross-correlations in seismic interferometry?&lt;/p&gt;&#xA;" OwnerUserId="12983" LastActivityDate="2018-06-29T14:24:00.920" Title="Spectral Whitening, Seismic Interferometry" Tags="|seismic|microseism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14519" PostTypeId="1" AcceptedAnswerId="16829" CreationDate="2018-06-28T21:27:34.297" Score="6" ViewCount="243" Body="&lt;p&gt;I have a conspiracy-prone friend who believes that people are controlling the weather to ensure good weather for a large, annual festival (last weekend in June in San Francisco). As a scientist, (not earth science), I was interested in testing this hypothesis. So..I built 2 linear models--one representing the days leading up to the festival, one representing the days following the festival-- where the I regressed max daily temperature onto the number of days away from the festival. Lo and behold, indeed the temperature did appear to rise, peak on the weekend of the festival, and then drop afterwards! Next I figured, it must just be a natural trend, irrespective of local festivities (and weather-controlling overlords). So next, I included data from the years before the festival began (1972), made two groups (pre-festival and post-festival) and included a days_away_from_festival*group interaction term. To my great surprise, the interaction was significant! Testing only the group dated before the festival began, did not yield significant results.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And so! My question is... can any of you experts explain this by means other than a statistical coincidence/wealthy weather gods? Why might the temperature in San Francisco tend to rise in the week leading up to the last weekend in June, and then fall afterwards--but for this effect not to be present in the years before 1970'sish?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: Here are my two models. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first model represents the days leading up to the festival and days are indicated by the countdown variable, (e.g. Friday = -1, Saturday = 0) There are 5 days prior included in the model. The group variable refers to the fact that I split the years into two groups, old:(1942-1971) and new:(1972-2017). TMAX is the maximum temperature of the day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bjN0g.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bjN0g.png&quot; alt=&quot;pre festival model&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second model is the same except it represents the days following the festival.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/urNr3.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/urNr3.png&quot; alt=&quot;post festival model&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, after 1972 the temperature seems to rise, peak during the festival in the last weekend in June, and then fall immediately after. However, this effect was not present prior to 1972.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT2: The data came from &lt;a href=&quot;https://www.ncei.noaa.gov&quot; rel=&quot;noreferrer&quot;&gt;https://www.ncei.noaa.gov&lt;/a&gt; and the station is San Francisco Downtown&lt;/p&gt;&#xA;" OwnerUserId="13256" LastEditorUserId="13256" LastEditDate="2018-06-29T05:12:53.473" LastActivityDate="2019-04-26T15:44:46.477" Title="Debunking weather conspiracy with statistics - why does temperature rise then fall for last weekend in June in recent years" Tags="|temperature|models|" AnswerCount="2" CommentCount="25" ContentLicense="CC BY-SA 4.0" />
  <row Id="14520" PostTypeId="1" AcceptedAnswerId="15456" CreationDate="2018-06-28T22:27:59.877" Score="7" ViewCount="161" Body="&lt;p&gt;I know about the seasonal changes of the altitude of the tropopause as well as the differences by latitude. I thought the change at one location was a very slow process, but I just found &lt;a href=&quot;http://en.vedur.is/weather/aviation/upper-air-observations/&quot; rel=&quot;noreferrer&quot;&gt;upper air observations through radiosounding&lt;/a&gt; from Iceland where I could see that the altitude of the tropopause changes up to 7000ft (over 2km) within 12 hours, such as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zSeOR.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zSeORm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/hjxpt.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hjxptm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What exactly happens in the atmosphere when the altitude of the tropopause changes that rapidly? Is air moving horizontally? Vertically? Is air exchanging heat energy with surrounding air? My best guess would now be that since the polar jet stream is above Iceland, it transports vast amounts of air, so an observer in Iceland each day sees different atmospheric conditions when looking upwards. How close to reality is that guess?&lt;/p&gt;&#xA;" OwnerUserId="13255" LastEditorUserId="6298" LastEditDate="2018-07-02T14:43:50.390" LastActivityDate="2018-11-28T14:01:45.360" Title="What happens in the upper air when the altitude of the tropopause changes?" Tags="|meteorology|atmosphere|troposphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14521" PostTypeId="1" CreationDate="2018-06-29T01:09:07.790" Score="1" ViewCount="38" Body="&lt;p&gt;I remember reading a long time ago in a meteorology book that certain dust storms were caused by a rapid descent of a large air mass. As the air is pressed against the ground, it is forced to spread outward at a high velocity, whipping up dirt along the way. A similar effect can be viewed with water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you were to pour a stream of water onto the ground, you could observe that the beads of water near the contact site are spreading outward more quickly than the velocity of the stream, before drag forces slow them down. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, that was years ago, I don't remember the book or the name of the phenomena. &lt;/p&gt;&#xA;" OwnerUserId="12086" LastActivityDate="2018-06-29T01:09:07.790" Title="Is there a conventional name for when wind speed increases as a result of a large descending air mass?" Tags="|meteorology|storms|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="14525" PostTypeId="2" ParentId="14491" CreationDate="2018-06-29T07:53:06.040" Score="7" Body="&lt;p&gt;Look at the pysolar docs (&lt;a href=&quot;http://pysolar.readthedocs.io/en/latest/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://pysolar.readthedocs.io/en/latest/&lt;/a&gt;) under &amp;quot;Estimate of clear sky radiation&amp;quot;. The algorithm does not return zeros at night, but instead just plugs those numbers straight in, giving nonsensical values. Filter the results so that if &lt;code&gt;altitude_deg&lt;/code&gt; &amp;lt; 0, the radiation is 0. An example just using pysolar, datetime, and pyplot (I don't use pandas, so I can't comment on that) and lists looks like:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import datetime&#xA;import matplotlib.pyplot as plt&#xA;import pysolar&#xA;lat, lon = 39.9075, 116.39723  # Beijing, China&#xA;timezone = datetime.timezone(datetime.timedelta(hours=8))  # 0800 UTC&#xA;start = datetime.datetime(2018,1,1,tzinfo=timezone)  # 1 Jan 2018&#xA;&#xA;# Calculate radiation every hour for 90 days&#xA;nhr = 24*90&#xA;dates, altitudes_deg, radiations = list(), list(), list()&#xA;for ihr in range(nhr):&#xA;    date = start + datetime.timedelta(hours=ihr)&#xA;    altitude_deg = pysolar.solar.get_altitude(lat,lon,date)&#xA;    if altitude_deg &amp;lt;= 0:&#xA;        radiation = 0.&#xA;    else:&#xA;        radiation = pysolar.radiation.get_radiation_direct(date,altitude_deg)&#xA;    dates.append(date)&#xA;    altitudes_deg.append(altitude_deg)&#xA;    radiations.append(radiation)&#xA;&#xA;days = [ihr/24 for ihr in range(nhr)]&#xA;fig, axs = plt.subplots(nrows=2,ncols=1,sharex=True)&#xA;axs[0].plot(days,altitudes_deg)&#xA;axs[0].set_title('Solar altitude, degrees')&#xA;axs[1].plot(days,radiations)&#xA;axs[1].set_title('Solar radiation, W/m2')&#xA;axs[1].set_xlabel('Days since ' + start.strftime('%Y/%m/%d %H:%M UTC'))&#xA;plt.show()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/t5MAT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/t5MAT.png&quot; alt=&quot;Altitude and radiation plot&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1342" LastEditorUserId="22114" LastEditDate="2021-03-27T17:03:08.797" LastActivityDate="2021-03-27T17:03:08.797" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14526" PostTypeId="2" ParentId="14514" CreationDate="2018-06-29T08:07:20.013" Score="2" Body="&lt;p&gt;The full answer is that you're moving through the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ekman_layer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ekman layer&lt;/a&gt;. In the upper atmosphere, away from the ground, the wind direction is such that the Coriolis force and the pressure gradient balance each other, for the most part. Near the surface, you also have turbulent friction/drag and all three components of the force have to balance. If you follow the math on that Wikipedia page and work through a few examples, you should be able to convince yourself that the wind turns by about 30 degrees clockwise as you go from the surface to the free atmosphere in the northern hemisphere, regardless of the wind direction in the free atmosphere or the height of the boundary layer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Observations show evidence of the Ekman spiral, though it's definitely not as clean as the theory and the number of 30 degrees is an approximation. I'm actually more familiar with the Ekman spiral from oceanography, where the key results are that the water on the surface of the ocean flows 45 degrees clockwise from the wind, and the net boundary layer transport of water is 90 degrees from the wind.&lt;/p&gt;&#xA;" OwnerUserId="1342" LastActivityDate="2018-06-29T08:07:20.013" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14527" PostTypeId="2" ParentId="14514" CreationDate="2018-06-29T11:00:15.050" Score="3" Body="&lt;p&gt;First forget about the cardinal directions and accept the next notions about the directions of forces relative to the air flow. The air parcel is affected by the pressure force towards the low pressure. The Coriolis force pulls air 90 degrees to the right relative to the current wind direction. The friction force that affects the flow is always directed to the opposite from the current wind direction. Assuming that the flow is in equilibrium (it is approximately most of the time) the next schematic applies (in the Northern Hemisphere) (from &lt;a href=&quot;https://www.weather.gov/source/zhu/ZHU_Training_Page/winds/Wx_Terms/Flight_Environment.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;weather.gov training page&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fte4a.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fte4a.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The left part of the schematic applies when there is no friction (i.e. not near the surface) and the wind is parallel to the isobars therefore called Geostrophic wind. The right part is with friction where the wind direction has turned approximately 30 degrees counterclockwise relative to the case aloft.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I deduce from your question that you are also grasping on why the Coriolis force is to the right of related to the wind direction. In fact there is no Coriolis force, but an effect that is seen as an apparent force due to our perception fixed on the rotating earth as the frame of reference. Basically the air parcel only appears to be forced to the right/left in the Northern/Southern Hemisphere. This is quite hard to explain intuitively and I remember first learning this through videos and animations like this &lt;a href=&quot;https://www.youtube.com/watch?v=IOcrHOc23N4&quot; rel=&quot;nofollow noreferrer&quot;&gt;open course video&lt;/a&gt; of rotating reference frames.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastActivityDate="2018-06-29T11:00:15.050" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14528" PostTypeId="2" ParentId="14518" CreationDate="2018-06-29T14:24:00.920" Score="1" Body="&lt;p&gt;I'm not an expert on this topic. But my understanding of seismic interferometry is that we try to obtain the 'Green's function' between various receivers. This Green's function is the equivalent of sending a spike pulse (i.e., delta function $\delta$) at one receiver, and recording the result at the other receiver. Once we have plenty of these Green's functions, ideally surrounding an area of interest, we can compute arbitrary Green's function recordings by evaluating a set of convolutions (rather than carrying out computations). It will be as if there is a recorder anywhere we want to record the signal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the time-domain, this $\delta$-spiked source is a source that's on for an infinitesimally small amount of time before switching off again. As you can maybe imagine, this source will have an infinitesimally small wavelength. We will thus be able to see every modulation of the signal as a single identifiable event in time: a scatter of amplitude $A_1$ happens after $t_1$ seconds, a reflection with amplitude $A_2$ happens after $t_2$ seconds, etc. Thus, we gain an incredibly high-resolution understanding of the medium in-between!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The frequency spectrum of such a $\delta$-spike has uniform amplitude. All frequencies are thus represented. It is called a 'broadband signal'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In reality, we do not obtain $\delta$-spikes very often because the predominant frequencies in the data are provided by noise with a specific frequency, usually a very low one. This low-frequency, or long-wavelength, property makes the obtained Green's functions of very low frequency. Different events will smear and overlap in time. This makes it more difficult to interpret the medium from the obtained Green's functions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Spectral whitening is a process that boosts frequencies with a low amplitude, to try and make any signal &lt;em&gt;more&lt;/em&gt; $\delta$-pulse-like. See for example here &lt;a href=&quot;https://twitter.com/DownUnderGeo/status/984324387720527872&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://twitter.com/DownUnderGeo/status/984324387720527872&lt;/a&gt; for an example from active seismic exploration, how boosting the amplitude of higher frequencies (while retaining the low ones), doesn't just look nicer, but provides a considerable increase in identifiable events! The same principle applies to seismic interferometry. By filtering the data, we obtain a more $\delta$-like behavior, thus obtain a more broadband signal from a less-than-ideal signal.&lt;/p&gt;&#xA;" OwnerUserId="12155" LastActivityDate="2018-06-29T14:24:00.920" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14529" PostTypeId="2" ParentId="14514" CreationDate="2018-06-29T14:54:06.817" Score="5" Body="&lt;p&gt;There have been a number of answers here that answer slightly different questions. As I understand it the question is &quot;Why does the Coriolis force apply to objects (or air parcels) moving east and west, as well as those with a north/south component?&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's a good question. The common intuitive explanation of the Coriolis effect, which you describe, considers only the horizontal forces acting on an object. That isn't quite right. This diagram adds two more forces that matter:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/rwedC.png&quot; alt=&quot;Diagram showing gravitational and centrifugal forces&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The arrow marked &quot;g&quot; is the force due to gravity, and is directed towards the centre of the planet.&#xA;The other arrow represents the centrifugal force that results from the earth's spin. Notice that it does not directly oppose gravity, but instead acts away from the earth's axis of rotation. In the absence of aerodynamics, buoyancy, etc, the vertical components of these forces must cancel out so that our particle maintains its altitude, but there is a resultant horizontal force towards the equator.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's assume that our red dot is stationary with respect to the earth's surface (the horizontal component of the centrifugal force must be balanced by something else). If the red dot accelerates to the east (away from us), meaning that its angular speed around the axis of rotation of the earth is increased, then the centrifugal force will increase, while the gravitational force will remain (very nearly) the same. Thus it's no longer in equilibrium. This has two effects: the vertical component of this is a force upwards which I believe is known as the &lt;a href=&quot;https://en.wikipedia.org/wiki/E%C3%B6tv%C3%B6s_effect&quot; rel=&quot;nofollow noreferrer&quot;&gt;Eötvös effect&lt;/a&gt;, and the horizontal component is a force towards the equator (a right turn in the northern hemisphere), which is Coriolis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly if the dot accelerates to the west (towards us), its angular speed decreases, the centrifugal force decreases, and it is pushed down and away from the equator (a right turn in the northern hemisphere).&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2018-06-29T15:04:35.403" LastActivityDate="2018-06-29T15:04:35.403" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14530" PostTypeId="2" ParentId="14501" CreationDate="2018-06-29T17:44:50.030" Score="2" Body="&lt;p&gt;I did a little poking around and came across a few projects that might be interesting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Based on the work of &lt;a href=&quot;https://doi.org/10.1029/2001GC000252&quot; rel=&quot;nofollow noreferrer&quot;&gt;Peter Bird (2003)&lt;/a&gt; there's a github project (&lt;a href=&quot;https://github.com/fraxen/tectonicplates&quot; rel=&quot;nofollow noreferrer&quot;&gt;fraxen/tectonicplates&lt;/a&gt;) that hosts georeferenced data of most major plate boundaries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seeing as you're interested more in minor plate dynamics, there's another project called &lt;a href=&quot;http://www.gplates.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;GPlates&lt;/a&gt; that is an multi-OS open source visualizer for plate boundary dynamic reconstructions. While I haven't looked at the potential outputs available, I imagine you would be able to export data from this platform into a more traditional GIS data format (.shp, .gml) that could be read in GMT. &lt;/p&gt;&#xA;" OwnerUserId="5536" LastActivityDate="2018-06-29T17:44:50.030" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14531" PostTypeId="2" ParentId="13146" CreationDate="2018-06-30T15:07:50.260" Score="6" Body="&lt;p&gt;The River Indus in Jammu and Kashmir of India and Gilgit-Baltistan under Pakistan control is usually taken as the dividing line between Himalayas and Karakoram. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The River Gilgit, a tributary of the Indus flowing from the North-west has its confluence with the Indus from the North-East near the town of Juglot or Jaglot about 45 km south east of Gilgit on the Karakoram Highway in Gilgit District and then the Indus flows south from here. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The confluence between these rivers is known as &quot;Tri Junction Point&quot; or &quot;Junction Point of Three Mountain Ranges&quot;. It is located at the junction of the 3 lofty mountain ranges, the Karakoram, Himalayas and Hindukush. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;To the North of this confluence or to the north of both Indus and Gilgit rivers is Karakoram. &lt;/li&gt;&#xA;&lt;li&gt;To the south  of the Indus before merger and to the East after merger are the Himalayas&lt;/li&gt;&#xA;&lt;li&gt;To the south of Gilgit river and West of the merged Indus is Hindukush. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In the Ladakh district of India, there is an east west range called the Ladakh range to the north of Indus, and sometimes this is taken as an extension of Karakorams. Beyond or to the north of Ladakh Range is the Shyok River, a tributary of Indus that flows westwards and joins the Indus near Skardu, and more commonly the mountains to the north of Shyok are called Karakoram range.&lt;/p&gt;&#xA;" OwnerUserId="13264" LastEditorUserId="39" LastEditDate="2018-06-30T17:11:44.173" LastActivityDate="2018-06-30T17:11:44.173" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14534" PostTypeId="1" CreationDate="2018-07-01T19:41:30.187" Score="2" ViewCount="389" Body="&lt;p&gt;I am using the following equation (Theim/Dupuit) to determine radius of influence for an unconfined aquifer. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/e4lDm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/e4lDm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assume all other variables are held constant. If Q increases, does the Radius of influence R2 also increase? &lt;/p&gt;&#xA;" OwnerUserId="13269" LastEditorUserId="11430" LastEditDate="2018-07-10T09:47:56.810" LastActivityDate="2018-07-10T09:47:56.810" Title="Hydrology - Flowrate vs. radius of influence" Tags="|hydrology|groundwater|hydrogeology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14536" PostTypeId="1" AcceptedAnswerId="14540" CreationDate="2018-06-29T20:05:59.010" Score="4" ViewCount="1153" Body="&lt;p&gt;If you take a &lt;a href=&quot;https://www.google.ca/search?hl=en&amp;amp;biw=1280&amp;amp;bih=541&amp;amp;tbm=isch&amp;amp;sa=1&amp;amp;ei=8Yw2W8eUDovSwQKM34PwBQ&amp;amp;q=tectonic+plate+submerged&amp;amp;oq=tectonic+plate+submerged&amp;amp;gs_l=img.3...3902.7998.0.8115.15.15.0.0.0.0.256.1343.2j5j2.9.0....0...1c.1.64.img..6.3.528...0j0i8i30k1j0i24k1.0.txdLbVOS9Dk&quot; rel=&quot;nofollow noreferrer&quot;&gt;look&lt;/a&gt; at a &lt;a href=&quot;https://en.wikipedia.org/wiki/Asthenosphere#/media/File:Subduction-en.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;typical&lt;/a&gt; &lt;a href=&quot;https://e9350ade-a-62cb3a1a-s-sites.googlegroups.com/site/platetectonicsamyg/home/plate-boundaries/Convergence1.gif?attachauth=ANoY7cqjMuTj1xeLGnjqRrebI07r5UK-zFch-VYiTho0UY0-HnV7CsNaEgSuOz9HYtMzoYBWn0Tr-yhPeApLOzyq26ngTf9Cm1DkcuyeVGKliY2YmHG6Yw4hZd4uxe0-lgjcvPSCSJTQVH2GhcUxNzTPXxyi4puQbe2_iPMMuu3MvxlB-oubcxF0XQ0d6FbLUb2eWVcWpXrattVUO1xRH1eNhNy3GXVo2Cd60yihtQC7DnfxVl--6T61JbzTqOlB1g-yWVVRuAxw&amp;amp;attredirects=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;picture&lt;/a&gt; tectonic plate subducting under another plate, the subducting plate is always drawn as deep (seemingly tens of km) into molten rock, but the subducted part of the plate itself is not molten. Why are the subducted plates not drawn as shallower into the magma?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My logic looking at this is the following: the surrounding medium is hot enough to melt rock. Alright, rock may take time to melt. A typical continental plate moves 10cm/year which yields 100,000 years / 10km. Is an order of a hundred thousand years really not enough time to melt that subducted plate? Why are so many textbooks drawing it subducted and unmelted to such depths?&lt;/p&gt;&#xA;" OwnerUserId="13280" OwnerDisplayName="Yaroslav" LastEditorUserId="11430" LastEditDate="2018-07-07T09:29:23.593" LastActivityDate="2018-07-07T09:29:23.593" Title="Why doesn't subducted earth crust melt?" Tags="|thermodynamics|geophysics|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14538" PostTypeId="1" AcceptedAnswerId="14541" CreationDate="2018-07-02T03:52:45.823" Score="5" ViewCount="4851" Body="&lt;p&gt;Is there a map that shows places where the temperature changes the least season to season? Is there a place on Earth where the temperature is the most constant in a comfortable range?&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2018-08-08T19:31:38.967" LastActivityDate="2018-08-08T19:31:38.967" Title="Where on Earth has the least changing temperature?" Tags="|atmosphere|temperature|geography|mapping|" AnswerCount="1" CommentCount="9" ClosedDate="2018-07-02T14:21:06.220" ContentLicense="CC BY-SA 4.0" />
  <row Id="14540" PostTypeId="2" ParentId="14536" CreationDate="2018-07-02T09:54:17.440" Score="7" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;...the submerging plate is always drawn as deep (seemingly tens of km) into molten rock...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It's actually hundreds of kilometres, not tens of them. But let me correct a common misconception:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The mantle is solid rock. It is &lt;em&gt;not&lt;/em&gt; molten rock.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So subduction leads solid rock into more solid rock.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the surrounding medium is hot enough to melt rock&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The surrounding medium is hot enough to melt rock only under very special circumstances, the two most common being:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;If the rock gains water somehow (yes, water under pressure helps rock to melt), or&lt;/li&gt;&#xA;&lt;li&gt;If even hotter rock from down below rises up and decompresses.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Why are so many textbooks drawing it submerged and unmelted to such depths?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Because it doesn't melt. The subducting plate goes down faster than it heats up. Therefore, pressure increases faster then temperature. This does not allow melting of the subducting slab.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What does happen? The slab loses water. Remember - this was oceanic crust and it's wet. On moderate heating, the water from hydrous minerals (serpentine etc) is lost to the mantle rocks above it. Because the mantle rocks above the slab &lt;em&gt;are&lt;/em&gt; hot, the addition of water causes them to melt. We see this all the time in the form of arc volcanoes. The Pacific &quot;rim of fire&quot; is the most famous example of this process.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would say that some very limited amount of melting may actually happen, but in terms of volume % of the entire slab it's likely to be negligible. The contribution of this melting to global volcanism is also likely to be negligible.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-07-02T09:54:17.440" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14541" PostTypeId="2" ParentId="14538" CreationDate="2018-07-02T11:16:39.137" Score="12" Body="&lt;p&gt;To answer the first question, yes, there are maps showing the seasonal temperature variation, for example &lt;a href=&quot;http://ftp.comet.ucar.edu/ootw/tropical/textbook_2nd_edition/navmenu.php_tab_2_page_6.1.0.htm&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/krbHQ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/krbHQ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unsurprisingly, the equatorial areas have the least variation because the angle of the sun relatively to the earth changes the least with seasons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding nice weather- I have worked as a geologist in northern South America and the Caribbean. In the lower lying areas (e.g. Aruba) I often thought it was too hot to be pleasant to work, but beachgoers think that was perfect weather. In the mountains it was often more pleasant, subjectively.&#xA;One city I visited where the temperature is remarkably stable is Medellin in Colombia - the &quot;city of eternal spring&quot;. Situated close to the equator, temperature is always nice there (&lt;a href=&quot;https://en.wikipedia.org/wiki/Medell%C3%ADn#Climate&quot; rel=&quot;noreferrer&quot;&gt;daily mean at 22 degrees throughout the year&lt;/a&gt;), but it can have a lot of rainy days. &lt;/p&gt;&#xA;" OwnerUserId="4783" LastActivityDate="2018-07-02T11:16:39.137" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14542" PostTypeId="2" ParentId="14536" CreationDate="2018-07-02T12:16:05.137" Score="0" Body="&lt;p&gt;Gimelist has given a good and fairly thorough answer, I would add that the insulative quality of rock is also a major contributor to it's extended survival at high temperatures. While the surface of the slab undergoes thermo-chemical reactions, like those that liberate carbon dioxide and water from sedimentary clays in their surface layers the inner material is insulated from heat transfer for decades because solid rock is a very poor conductor of heat, inner being anything more than a few millimeters below the surface.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="10735" LastEditDate="2018-07-02T19:49:23.120" LastActivityDate="2018-07-02T19:49:23.120" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14543" PostTypeId="1" CreationDate="2018-07-03T09:12:11.207" Score="0" ViewCount="52" Body="&lt;p&gt;Azerbaijan appears to have vast development in its oil sector.  Images on google earth show oil platforms connected by road ways far out into the Caspian Sea of the coast of Baku.  Why is the majority of the sea un available to view. How vast are these deposits?&lt;/p&gt;&#xA;" OwnerUserId="11565" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T11:56:02.813" LastActivityDate="2019-08-29T11:56:02.813" Title="Caspian Sea oil deposits" Tags="|oceanography|models|petroleum|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14544" PostTypeId="1" CreationDate="2018-07-03T11:12:29.490" Score="1" ViewCount="177" Body="&lt;p&gt;I'm trying to plot Moist static energy fluxes (vectors) and their divergence like the attached Figure. I have monthly means of u, v, temperature, specific humidity and geopotential from(1000-100 hPa) for calculating MSE, but my results are very different from the attached figure. I also want to know how to calculate the northward and eastward fluxes for plotting MSE vectors on the map. What procedure must be used to obtain these variables? Is there a special process?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/by24Q.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/by24Q.jpg&quot; alt=&quot;Atmospheric moist static energy fluxes F (vectors)&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13274" LastEditorUserId="39" LastEditDate="2018-07-03T12:58:06.153" LastActivityDate="2018-07-03T12:58:06.153" Title="Plotting moist static energy fluxes" Tags="|meteorology|climatology|energy-balance|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14545" PostTypeId="1" CreationDate="2018-07-03T14:39:25.447" Score="1" ViewCount="948" Body="&lt;p&gt;Regarding &lt;a href=&quot;https://en.wikipedia.org/wiki/Afro-Eurasia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Afro-Eurasia&lt;/a&gt; as single continent, I tried to draw longest geodesic line within it and got&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LwADQ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LwADQ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZW2bC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZW2bC.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;which is 16628 km (10 332 miles) length.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looks like this line is rather stable and lasts from &lt;a href=&quot;https://ru.wikipedia.org/wiki/%D0%9D%D0%B0%D0%B2%D0%B0%D1%80%D0%B8%D0%BD_(%D0%BC%D1%8B%D1%81)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Navarin cape&lt;/a&gt; in Russia to Quoin point in SAR.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this known feature is this really longest and what is it's name?&lt;/p&gt;&#xA;" OwnerUserId="13275" LastActivityDate="2018-07-03T14:39:25.447" Title="Longest land path on Afro-Eurasia" Tags="|geography|terminology|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14546" PostTypeId="1" CreationDate="2018-07-03T19:08:52.960" Score="4" ViewCount="2489" Body="&lt;p&gt;According to &lt;a href=&quot;https://www.statista.com/statistics/264024/number-of-merchant-ships-worldwide-by-type/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Statista&lt;/a&gt;, as of January 2017, there are approximately 52,000 ships currently operating in the merchant fleet and 11,000 of these are considered bulk carriers.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How many ships are there in the world? The number of ships in the world exceeds 50,000: As of January 2017, there were 52,183 ships in the world's merchant fleets. General cargo ships are ranked as the most common type of ship in the global merchant fleet, accounting for about a third of the fleet: There were almost 17,000 such ships in the merchant fleet as of the beginning of 2017. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://en.wikipedia.org/wiki/Batillus-class_supertanker&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;, the Batillus class bulk carrier, unloaded, displaces 77,300 tonnes of water and 630,962 tonnes when under a full load. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Assuming a range between 850,300,000 and 6,937,612,000 tonnes of displaced water, what would be the acceptable average range of water that could be displaced by the merchant fleet during daily operation?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://www.livescience.com/6470-ocean-depth-volume-revealed.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ocean's Depth and Volume Revealed - Live Science&lt;/a&gt;, the ocean's volume is approximately 1.332e+18 cubic metres&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A group of scientists used satellite measurements to get new estimates of these values, which turned out to be 0.3 billion cubic miles (1.332 billion cubic kilometers) for the volume of the oceans and 12,080.7 feet (3,682.2 meters) for the average ocean depth.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;How much does that displaced water raise the sea levels?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="13276" LastActivityDate="2020-04-29T00:20:48.603" Title="How much ocean water is currently being displaced by ships?" Tags="|ocean|water|sea-level|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14547" PostTypeId="1" AcceptedAnswerId="14549" CreationDate="2018-07-03T20:03:53.643" Score="-1" ViewCount="2530" Body="&lt;p&gt;What would the effects of detonating every single nuclear bomb currently in existence at once in the center of the earth? Would the earth simply explode into bits? Would the heat have some sort of effect on the surface?&lt;/p&gt;&#xA;" OwnerUserId="7151" LastActivityDate="2018-07-22T06:28:19.337" Title="What if we detonated the entire worlds nuclear supply in the center of the earth?" Tags="|temperature|core|crust|mass-extinction|" AnswerCount="2" CommentCount="6" ClosedDate="2018-07-12T07:29:51.693" ContentLicense="CC BY-SA 4.0" />
  <row Id="14548" PostTypeId="1" CreationDate="2018-07-03T21:57:07.823" Score="1" ViewCount="272" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8Kt07.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8Kt07.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.pakistantoday.com.pk/2018/07/03/video-huge-sinkhole-emerges-on-lahores-mall-road-after-heavy-rain/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here is a video&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why did the sinkhole emerge in Pakistan? Is this because of the heavy exploitation of groundwater?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What could be the solution?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;   &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://tribune.com.pk/story/1748641/1-pictures-chaos-rain-continues-lash-lahore/&quot; rel=&quot;nofollow noreferrer&quot;&gt;In pictures: Chaos as rain continues to lash Lahore&lt;/a&gt;   &lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.dawn.com/news/1417680&quot; rel=&quot;nofollow noreferrer&quot;&gt;NDMA sends out monsoon alert, expects more urban flooding in Lahore, Rawalpindi&lt;/a&gt;  &lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://dunyanews.tv/en/Pakistan/446353-Sinkhole-emerges-near-GPO-Mall-Road--&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sinkhole emerges near GPO on Mall Road&lt;/a&gt;  &lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.geo.tv/latest/201794-lahore-crack&quot; rel=&quot;nofollow noreferrer&quot;&gt;Those responsible for Lahore sinkhole will be punished: Interim transport minister&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerDisplayName="user13277" LastEditorDisplayName="user13277" LastEditDate="2018-07-04T15:55:33.710" LastActivityDate="2018-07-04T21:47:22.767" Title="Why did sinkholes emerge in Pakistan?" Tags="|crust|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14549" PostTypeId="2" ParentId="14547" CreationDate="2018-07-04T01:03:47.093" Score="8" Body="&lt;p&gt;I'll ignore the complete impossibility of getting the world's nuclear arsenal to the center of the Earth and the impossibility of exploding them all at once. The total number of nuclear weapons, including those held in reserve and those scheduled for dismantling, is about 15000, with an average explosive power of less than half a megaton of TNT. This is equivalent to about 7×10&lt;sup&gt;18&lt;/sup&gt; joules of energy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's about how much energy humanity consumes every five days. Compared to other destructive events, it's about 1/5000th of the energy released by the 2004 Indian Ocean earthquake, about 1/70000th of the energy released by the Chicxulub impactor, and about 1/30000000000000th of the energy needed to make the Earth explode into bits (the Earth's gravitational binding energy).&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-07-04T01:03:47.093" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14550" PostTypeId="1" CreationDate="2018-07-04T01:51:11.117" Score="1" ViewCount="412" Body="&lt;p&gt;What is the translation speed of a tropical cyclone and how can it be calculated from model outputs? I have mean sea level pressure, u-wind and v-wind.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand that it is the linear speed at which tropical cyclone moves forward. &lt;/p&gt;&#xA;" OwnerUserId="3194" LastEditorUserId="2470" LastEditDate="2018-07-06T09:37:49.603" LastActivityDate="2018-07-07T03:19:15.627" Title="Calculation of translation speed of a tropical cyclone from output data from models?" Tags="|tropical-cyclone|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14553" PostTypeId="2" ParentId="14548" CreationDate="2018-07-04T21:29:47.920" Score="4" Body="&lt;p&gt;I was about to ask a question whether this should be classified as a sinkhole or not. This is because this so-called 'sinkhole' is not entirely because of a natural process. It seems that it was the underground GPO Station (or the tunnel) of &lt;a href=&quot;https://en.wikipedia.org/wiki/Orange_Line_(Lahore_Metro)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Orange Line Metro Train&lt;/a&gt; Station that collapsed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can't seem to find an article that specifically mentions this. One &lt;a href=&quot;https://tribune.com.pk/story/1748529/1-least-six-dead-rain-related-incidents-lahore/&quot; rel=&quot;nofollow noreferrer&quot;&gt;news article&lt;/a&gt; I found isn't exactly very clear about it, but suggests this to be the case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think you can blame the 'sinkhole' (or collapse) or the failure of the underground structure. One of your source's title &quot;Those responsible for Lahore sinkhole will be punished&quot; also seems to suggest that it has only man-made causes, and not natural.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further sources:&#xA;&lt;a href=&quot;https://pma.punjab.gov.pk/olmts&quot; rel=&quot;nofollow noreferrer&quot;&gt;Punjab Mass Transit Authority - Orange Line Metro&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;P.S. I live here. :)&lt;/p&gt;&#xA;" OwnerUserId="13284" LastEditorUserId="13284" LastEditDate="2018-07-04T21:47:22.767" LastActivityDate="2018-07-04T21:47:22.767" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14554" PostTypeId="1" AcceptedAnswerId="14556" CreationDate="2018-07-04T21:46:02.290" Score="4" ViewCount="614" Body="&lt;p&gt;Imagine there's an underground man made structure e.g. a tunnel or an underground train station that collapses creating a depression in the surface. Would that technically be called a sinkhole? What is the exact definition of a sinkhole (for someone illiterate in earth sciences, please, thanks.)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Sinkhole#Artificial_processes&quot; rel=&quot;noreferrer&quot;&gt;wikipedia article&lt;/a&gt; on sinkholes seems to suggest that they should be called collapses and not sinkholes:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Collapses, commonly &lt;strong&gt;&lt;em&gt;incorrectly&lt;/em&gt;&lt;/strong&gt; labeled as sinkholes also occur due to human activity, such as the collapse of abandoned mines and salt cavern storage in salt domes in places like Louisiana, Mississippi and Texas. More commonly, collapses occur in urban areas due to water main breaks or sewer collapses when old pipes give way.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(emphasis mine)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The media keeps calling them sinkholes. A google search on sinkholes will give numerous news articles that call these incidents sinkholes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;P.S. Sorry about the tags. Not sure what tags to use.&lt;/p&gt;&#xA;" OwnerUserId="13284" LastEditorUserId="13284" LastEditDate="2018-07-04T22:05:30.660" LastActivityDate="2018-07-05T04:43:44.773" Title="Is an underground mine collapse or a tunnel collapse called a sinkhole?" Tags="|geology|geophysics|land-surface|erosion|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14555" PostTypeId="2" ParentId="14554" CreationDate="2018-07-05T02:58:19.283" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is an underground mine collapse or a tunnel collapse called a sinkhole?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Technically, Yes. But, not the actual one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sinkholes are a result of a natural phenomenon caused by the erotion of underground rock layers mostly made of limestones. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most popular case of sinkholes is in Guatemala which is/was natural.&lt;/p&gt;&#xA;" OwnerDisplayName="user13277" LastActivityDate="2018-07-05T02:58:19.283" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14556" PostTypeId="2" ParentId="14554" CreationDate="2018-07-05T04:43:44.773" Score="6" Body="&lt;p&gt;This is probably more of an English language question than a science question. &#xA;The answer to it depends on the extent of a person's vocabulary &amp;amp; knowledge of a particular field of engineering.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Over a period of time, in the media I have read &amp;amp; heard mine &quot;tunnels&quot; incorrectly being called shafts. Mine shafts are vertical or near vertical. What most people call mine &quot;tunnels&quot;, people in the industry call drifts or drives - these are horizontal or near horizontal. The word tunnel is better applied to civil items of infrastructure rather than mines: such as rail or vehicular tunnels or tunnels to access underground bunkers or storage facilities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly, a tunnel or mine collapse could be termed a sinkhole and people not familiar with either the civil engineering or mining fields might do that - particularly journalists. People in the civil or mining fields would use terms such as tunnel collapse or mine subsidence hole.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-07-05T04:43:44.773" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14557" PostTypeId="2" ParentId="14547" CreationDate="2018-07-05T11:33:48.520" Score="3" Body="&lt;p&gt;To add to David Hammen's answer.   Earth is big.   I hate to use the words &quot;really really big&quot; cause there are things much bigger, like the sun, but Earth is quite large.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Imagine what would happen if all the Nukes went off 3000 miles from you.  You're in LA, the bombs are all set off in NY.   The curvature of the Earth would prevent you from seeing much, except just barely maybe the very top spread of the mushroom cloud and some reflection of the glow and redness in the sky and you might experience a gust of wind from the blast and a short while later, some radioactive fallout and you'd begin to have a bad time within a day or a few days, but the blast probably wouldn't kill you (I'm speculating a bit, but 3000 miles is outside the immediate blast radius.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.todayifoundout.com/index.php/2013/07/the-story-of-the-tsar-bomba/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Tsar bomb, the biggest nuke ever set off, had a blast radius&lt;/a&gt; of 22 miles (35 km) and it leveled a village 34 miles (55 km) away.   With the inverse square rule, 100 tsar bombs might have a blast radius 10 times that, or 220 miles and would still knock down buildings further than that.   But once you get a couple thousand miles away, even if every nuke in the world is set off, you'd survive the blast, though you'd might feel the pressure wave (wind) generated by it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now imagine instead of air separating you and all those Nukes, there's 3,000 miles of rock and metal.   You'd barely notice it.  Odds are, you wouldn't notice it at all.   There's simply not enough heat, and not enough explosive expansion to affect the Earth's core.   There would be a pressure wave for sure, but by the time it reached the surface, my guess is you wouldn't even feel it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's two kinds of pressure waves that are generated by Earthquakes.   &lt;a href=&quot;https://en.wikipedia.org/wiki/S-wave&quot; rel=&quot;nofollow noreferrer&quot;&gt;S waves&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/P-wave&quot; rel=&quot;nofollow noreferrer&quot;&gt;P waves&lt;/a&gt;.   If you set off nukes inside the Earth's core the pressure waves would primarily be P waves, that would spread out evenly towards the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using David Hammen's 7 x 10&lt;sup&gt;18&lt;/sup&gt; joules of energy and Earth's surface area of 5.1 x 10&lt;sup&gt;14&lt;/sup&gt; square meters.  That's about 1400 joules per square meter, which sounds like a lot, but considering that it would be spread out as it travels through the Earth, and compared to local Earthquake energy, that probably wouldn't be much more than a very weak somewhere in the 1-2 on the Richter scale (very bad guess which I'll try to improve on), but based on how much energy a large earthquake has, and if the energy is divided 50% into P wave and 50% into S wave (another bad estimate), 1400 joules per square meter, after having traveled through 3,000 miles of earth would have to be very low on the Richter scale.   I'm pretty confident that no person would feel it, but as noted by Jamesqf, it might be detected by sensitive equipment.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The added heat to the core would be even more negligible and I imagine that would have no measurable effect at all. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If someone wants to improve on this answer from a P-wave and earthquake energy perspective, I can delete mine.   The bottom line is nothing of consequence would happen.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="725" LastEditDate="2018-07-22T06:28:19.337" LastActivityDate="2018-07-22T06:28:19.337" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14558" PostTypeId="1" CreationDate="2018-07-05T13:50:42.220" Score="4" ViewCount="443" Body="&lt;p&gt;Due to extensive damage to my face because of an accident, I am currently undergoing skin therapy (laser/IPL/medication), that makes my skin extremely sensitive to UV radiation. So I need to stay out of the sun, at the very least between 11:00 and 16:00, need to reapply sun screen every two hours, and generally be careful with exposure. Since that makes me hyper aware to the sun, perceived warmth, UV index and all that, it made me reasearch the subject.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I live in The Netherlands and the meteorology institute published real time UV measurements (as UV index) at &lt;a href=&quot;https://www.rivm.nl/Onderwerpen/Z/Zonkracht&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.rivm.nl/Onderwerpen/Z/Zonkracht&lt;/a&gt;&#xA;However the UV index is defined as the amount energy that is radiated on the flat surface of the earth. As we humans generally have more vertical surfaces, especially sensitive surfaces like the face, would it not make more sense to not just measure in the horizontal plane? Especially during the evening and the morning the sun is at a low angle, so the (relative) energy on a vertical plane would be a lot higher than the above graph suggests.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I made a small program that parses this image, and recalculates the UV index for the vertical plain (divide the UV index by the tangent of (90 degrees minus current zenith angle). This would be the output (blue line is vertical UV index):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/SDpj1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SDpj1.png&quot; alt=&quot;UV index in vertical plane&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13288" LastActivityDate="2021-05-26T12:40:07.020" Title="calculate UV index in vertical plane" Tags="|sun|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14559" PostTypeId="1" CreationDate="2018-07-05T18:43:11.627" Score="1" ViewCount="251" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Dv72K.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HNf2K.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4vnoU.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JHb6P.jpg&quot; alt=&quot;enter image description here&quot;&gt;&#xA;pink quartz looking stone 19 pounds found in a vehicle in new york state&lt;/p&gt;&#xA;" OwnerUserId="13291" LastActivityDate="2018-07-06T12:45:25.047" Title="is this a rose quartz" Tags="|crystals|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14560" PostTypeId="1" AcceptedAnswerId="16797" CreationDate="2018-07-05T18:59:45.230" Score="4" ViewCount="262" Body="&lt;p&gt;When I was first introduced to potential vorticity, I was told that it is a very important tool for meteorologists to learn. Sure, it solved a simple problem in dynamics, but it wasn't apparent to me at the time on why it was important.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I progress, I find that it becomes more and more useful in finding notable features, such as tropical cyclones and fronts. That being said, why isn't it plotted more often? I don't find plots of potential vorticity often, but when I do, it is often plotted for higher in the troposphere, and not where features are commonly found.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorDisplayName="user1066" LastEditDate="2019-04-23T03:06:42.313" LastActivityDate="2019-05-23T10:02:00.247" Title="Why is potential vorticity so emphasized in technical work, but often neglected in maps on weather websites?" Tags="|meteorology|atmosphere|dynamics|vorticity|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="14561" PostTypeId="2" ParentId="14558" CreationDate="2018-07-05T21:22:50.513" Score="1" Body="&lt;p&gt;To answer my own question: the principle is sound however the calculation does not work out, because it assumes only direct UV radiation, and not the real-world scenario of scattered UV radiation.&lt;/p&gt;&#xA;" OwnerUserId="13288" LastActivityDate="2018-07-05T21:22:50.513" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14562" PostTypeId="1" AcceptedAnswerId="14570" CreationDate="2018-07-06T02:08:25.797" Score="2" ViewCount="66" Body="&lt;p&gt;WA gets plenty hot and dry in the summer (especially Exmouth and points south where Top End moisture isn't as prevalent), but I don't hear so much about catastrophic forest fires hitting WA, like I do about those that hit SA, VIC/TAS, NSW/ACT/SE QLD year in and year (it's events in these states that most often make international news), with the odd exception like the Perth bushfires of November 2011. Is there a meteorological or geological reason that the WA wildfire season can be forgotten as compared to wildfires in the eastern states of Australia?&lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2018-07-07T09:28:37.490" Title="Why don't forest fires in Western Australia get as much attention as forest fires in the southeast of the country (including SA)?" Tags="|natural-disasters|forest|extreme-weather|fire|" AnswerCount="1" CommentCount="4" ClosedDate="2018-07-12T07:16:52.307" ContentLicense="CC BY-SA 4.0" />
  <row Id="14563" PostTypeId="1" CreationDate="2018-07-06T02:55:09.010" Score="5" ViewCount="81" Body="&lt;p&gt;I am using a Pandora spectrometer and a MAX-DOAS spectrometer to quantify the amount of formaldehyde (HCHO) present in the troposphere and stratosphere in Fairbanks, Alaska. Both the spectrometers use the Lambert-Beer's law for quantifying the amount of HCHO in the air by using different viewing geometries. I want to know what role does the view geometry play in the working of these spectrometers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KbDJK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KbDJK.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12661" LastEditorUserId="12661" LastEditDate="2018-07-06T04:02:45.097" LastActivityDate="2018-07-11T09:43:05.667" Title="What are the benefits of direct sun viewing spectrometer over a backscatter measuring spectrometer to quantify trace gases in the atmosphere?" Tags="|atmospheric-chemistry|air-pollution|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14564" PostTypeId="2" ParentId="14559" CreationDate="2018-07-06T12:45:25.047" Score="2" Body="&lt;p&gt;Yes, it is rose quartz. There are a number of mines in eastern New York near Vermont where rose quartz been found. Massive rose quartz can occur in granitic pegmatites.  I could not google to find images of any massive rose quartz from the northeastern United States but it is very similar in appearance to the rose quartz from Black Hill of South Dakota.  The rose quartz deposits from the Black Hills are the largest on earth and the material is sold world-wide.  Locally here in Ohio, I know of the landscaping company that has bulk rose quartz for sale.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You're specimen might be local to New York but might also be from elsewhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;https://www.mindat.org/min-3456.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mindat.org&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2018-07-06T12:45:25.047" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14569" PostTypeId="1" AcceptedAnswerId="16690" CreationDate="2018-07-07T04:39:35.090" Score="0" ViewCount="188" Body="&lt;p&gt;Would a circular lake have enough of sea breeze strong to create a gentle vortex in the center of the lake? Is there such a place on Earth where lake micro climate vortexes occur frequently? &#xA;The Vortex would still be a breeze and not visible during normal Lake Breeze conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://worldbuilding.stackexchange.com/questions/108896/could-a-city-be-built-out-of-balloons&quot;&gt;https://worldbuilding.stackexchange.com/questions/108896/could-a-city-be-built-out-of-balloons&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/13446/where-is-the-calmest-place-on-earth&quot;&gt;Where is the calmest place on Earth?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2019-04-12T19:30:15.290" LastActivityDate="2019-04-12T19:30:15.290" Title="Where on Earth is the most windless lake with its own micro climate sea breeze?" Tags="|geophysics|climate|geography|water|mapping|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14570" PostTypeId="2" ParentId="14562" CreationDate="2018-07-07T09:28:37.490" Score="3" Body="&lt;p&gt;Forest fires, and natural disasters in general, get attention when they affect people.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bush fires outside of metropolitan Perth or far away from populated areas do not affect many people. Therefore, media attention is diverted elsewhere. This is not unique to WA: you have the same in NT, northern SA, and the west of eastern states.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is also not unique to bush fires. Volcanoes only get media attention when they affect people: recent examples are Fuego in Guatemala or Kilauea in Hawaii. The other 50 or so active volcanoes in 2018 get close to zero media attention, because they do not affect anyone (or at least, they do not affect people that the Western media cares about).&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-07-07T09:28:37.490" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14571" PostTypeId="1" AcceptedAnswerId="14572" CreationDate="2018-07-07T11:51:34.283" Score="4" ViewCount="143" Body="&lt;p&gt;What exactly is an &quot;&lt;a href=&quot;https://www.sparc-climate.org/data-centre/data-access/us-radiosonde/us-upper-air-station-details/&quot; rel=&quot;nofollow noreferrer&quot;&gt;upper air station&lt;/a&gt;&quot;? I know they release radiosondes and manage the resulting data, but how does that occur?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I notice that some seem to be at universities. Does the National Weather Service basically hire a professor to release the radiosondes every day and then he pays graduate students, or local random people or what? What if the guy is sick? Is the system automated so no person is needed to launch the balloon?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What does the station look like? Is it like a warehouse, or an office at the university next to a launching field, or what? What are the facilities? Obviously they must have an antenna. Is that some gigantic tower, or is it just a little UHF antenna?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2018-07-09T10:29:07.597" Title="What exactly is an &quot;upper air station&quot;?" Tags="|national-weather-service|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14572" PostTypeId="2" ParentId="14571" CreationDate="2018-07-07T13:17:59.243" Score="4" Body="&lt;p&gt;You noticed they're often in University towns... but you may've missed that most sites are also in locations with National Weather Service offices:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/w4vQhm.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/w4vQhm.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/NCEvHm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NCEvHm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;sub&gt;&lt;sup&gt;Upper air stations (left) and NWS offices (right)&lt;/sup&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So NWS offices that are launch locations in the US include the twice (or more) per day launches in the responsibilities of its employees.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A few NWS Offices are indeed in buildings at universities (to foster cooperation between the office and research purposes); those include Tallahassee/FSU, Norman/SPC/NSSL/OU, Miami/NHC/FIU.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There may be a few launch sites not located NWS Office locations.  Most such sites are likely at other scientific facilities; I know XMR is actually at NASA's facilities in Cape Canaveral.  (Note: launches at XMR have indeed often been at odd times and been a bit less reliably done)  Still, it's possible that a few such stations are also standalone or at separate airports.  Indeed there certainly historically have been employees hired at many airport observation stations to supplement the (now) automated instruments with visual observations - I had a friend work at the Tallahassee Airport doing so only about a decade ago.  So it shouldn't be beyond reasoning that launches could be done at such spots if uniquely needed.  And I do expect some launch sites in &lt;a href=&quot;http://weather.uwyo.edu/upperair/sounding.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;other parts of the world&lt;/a&gt; are perhaps staffed in such ways (or by automated measures???). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I haven't actually been in the room where official launches are made, but at FSU saw quite a few from nearby offices, and have been around other sites too.  Still I don't know the precise specs on the equipment, but as far as I understand it, launch sites typically include either a shed/garage or rooftop platform room with a built-in large tube to launch into.  Such rooms hold the supplies and equipment.  Then there is indeed also a radio receiving station to get observations and movements back from the balloon:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WFEfq.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WFEfq.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From what I've seen, it typically takes a single person a few minutes to inflate the balloon, attach the equipment, and make the launch.  I know that at some sites in very difficult conditions (heavy winds)  multiple people may sometimes be needed to make the launch in order to control the large unwieldy balloon and equipment to prevent issues with tangling in nearby structures.  As mentioned, launch sites in built up areas often have a launch tube to help guide it on a safe starting trajectory.  In more sparse sites or NWS Offices at airports, they are indeed more like fields... so I believe they typically just go outside and release it from a spot clear of downwind obstructions.  Not the most fun in a thunderstorm or hurricane!  (Yes, there have been &lt;a href=&quot;https://twitter.com/nwscorpus/status/901225807137386496?lang=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;some amazing launches in such conditions&lt;/a&gt;!)&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-07-09T10:29:07.597" LastActivityDate="2018-07-09T10:29:07.597" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14573" PostTypeId="1" CreationDate="2018-07-07T19:39:34.797" Score="1" ViewCount="322" Body="&lt;p&gt;I've found several answers to the question of why the sky is blue.&lt;br&gt;&#xA;Basically the title. Elaborate however you want...&lt;/p&gt;&#xA;" OwnerUserId="13297" LastActivityDate="2018-07-07T19:39:34.797" Title="Why is the sky blue? Due to the ozone layer or due to ''light scatterization in atmosphere''?" Tags="|atmosphere|ozone|light|" AnswerCount="0" CommentCount="6" ClosedDate="2018-07-12T07:08:19.347" ContentLicense="CC BY-SA 4.0" />
  <row Id="14577" PostTypeId="1" CreationDate="2018-07-08T23:14:11.480" Score="5" ViewCount="53" Body="&lt;p&gt;Over what size temporal/spatial scales do geophysicists and geodynamicists begin to apply fluid dynamics to model the mantle rather than elastic/plastic deformation theory?&lt;/p&gt;&#xA;" OwnerUserId="11430" LastActivityDate="2018-07-08T23:14:11.480" Title="Over what scales can we begin to apply fluid dynamics to accurately model properties of the mantle?" Tags="|geophysics|geodynamics|fluid-dynamics|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14580" PostTypeId="2" ParentId="14534" CreationDate="2018-07-09T04:21:58.390" Score="2" Body="&lt;p&gt;I think your confusion is because you are keeping the head fixed. As you increase Q at fixed T the drawdown curve will become steeper when r1, h1, and h2 are fixed. That means r2 will move towards the pumping well.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2018-07-09T04:21:58.390" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14581" PostTypeId="1" AcceptedAnswerId="14583" CreationDate="2018-07-09T08:39:58.280" Score="21" ViewCount="3431" Body="&lt;p&gt;If one applies today's state-of-the-art weather forecast computations &quot;backwards&quot;, i.e. computing how the systems was X days &lt;em&gt;before&lt;/em&gt; the current situation based on knowledge of today's situation, at which point do &quot;predictions&quot; deviate significantly from the (known) sitautions ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, are those computations reversible and even possible?&#xA;And if so, is the error level comparabliy (i.e. time-symmetric) or not?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit:&#xA;Imagine one would get the data from an Earth-like planet through an observation (satelite etc.) at a given moment, would current weather-models allow to compute how the weather &lt;em&gt;was&lt;/em&gt; before that time?&lt;/p&gt;&#xA;" OwnerUserId="1334" LastEditorUserId="1334" LastEditDate="2018-07-09T12:21:37.967" LastActivityDate="2018-07-14T09:34:22.803" Title="Can the previous weather be computed from the current situation?" Tags="|meteorology|" AnswerCount="4" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="14582" PostTypeId="2" ParentId="14581" CreationDate="2018-07-09T12:52:16.827" Score="13" Body="&lt;p&gt;Validation is done by &lt;a href=&quot;https://en.wikipedia.org/wiki/Backtesting&quot; rel=&quot;noreferrer&quot;&gt;hindcasting&lt;/a&gt;, not by reversing the time axis, which seems to be what you're asking about.  In hindcasting, we take the state at some time in the past, apply our weather models to that state (and the state before it), run the forecast model, and compare that to the reference state¹ ahead of that point in time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a concept called &lt;em&gt;backtracking&lt;/em&gt;, which is (for example) used to calculate where particulates have been first emitted (so we measure some plume, and calculate this originated 18 hours ago at a particular source).  But this assumes knowledge of present &lt;em&gt;and past&lt;/em&gt; winds, and is therefore different from what you ask.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reversing the time axis would involve water falling up to the clouds and cyclones moving equatorward and turning into potential vorticity.  It seems involved and I'm not sure what benefit would be.  I don't think this can be  done with existing models, and it would be a lot of effort to make it work.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;¹ It's not as simple as that, because the full &quot;actual state&quot; also involves modelling to &quot;fill in the gaps&quot; in time and space, between all the times and places where we have measurements.  This is known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Meteorological_reanalysis&quot; rel=&quot;noreferrer&quot;&gt;re-analysis&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2018-07-09T13:35:36.047" LastActivityDate="2018-07-09T13:35:36.047" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14583" PostTypeId="2" ParentId="14581" CreationDate="2018-07-09T15:43:57.057" Score="19" Body="&lt;p&gt;The underlying equations for fluid-dynamic models are &lt;a href=&quot;https://en.wikipedia.org/wiki/Hyperbolic_partial_differential_equation&quot; rel=&quot;noreferrer&quot;&gt;hyperbolic partial differential equations&lt;/a&gt;. They can generally be written in the form&#xA;$$&#xA;  \frac{\partial}{\partial t} u(t) = D(u(t))&#xA;$$&#xA;where $D$ in some way evaluates the current state of the system and its spatial derivatives.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A numerical simulation then &lt;em&gt;integrates&lt;/em&gt; this differential equation, to extrapolate from a start state $u(t_0) = u_0$ the time-dependent $u(t)|_{t&amp;gt;t_0}$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Well, if we can do that, then surely we could also solve in the inverse time direction, by considering the equation&#xA;$$&#xA;  \frac{\partial}{\partial t} u(-t) = -D(u(t))&#xA;$$&#xA;and running the integrator with $\tilde t = -t$, $\tilde D = -D$?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Actually, you quickly run into problems when you try that. The operator $D$ can be characterised by its &lt;a href=&quot;https://en.wikipedia.org/wiki/Jacobian_matrix_and_determinant&quot; rel=&quot;noreferrer&quot;&gt;Jacobian&lt;/a&gt;, which basically tells you how pertubations in the state influence the derivative. Specifically, the complex &lt;em&gt;eigenvalues&lt;/em&gt; of the Jacobian can tell you whether a small deviation will &lt;strong&gt;a)&lt;/strong&gt; amplify over time (positive real part), or &lt;strong&gt;b)&lt;/strong&gt; decay (negative real part), or &lt;strong&gt;c)&lt;/strong&gt; just oscillate (purely imaginary).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For physical systems the eigenvalues tend to be mostly &lt;strong&gt;c)&lt;/strong&gt; or &lt;strong&gt;b)&lt;/strong&gt;: you get a lot of wave-like solutions which propagate / oscillate over the system, and tend to &lt;em&gt;decay&lt;/em&gt; over time. &lt;strong&gt;a)&lt;/strong&gt; however is more tricky: if you start with a small deviation from the start state, the system will over time deviate ever more and and more. Now, this kind of thing is by no means unheard of especially in meteorology; it's the essence of a &lt;a href=&quot;https://en.wikipedia.org/wiki/Chaos_theory&quot; rel=&quot;noreferrer&quot;&gt;chaotic system&lt;/a&gt;. Storms can emerge and grow stronger over time, but only by scooping up energy that's already stored in the system. At some point they'll stop.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;OTOH, you always have a lot of &lt;em&gt;consistently negative&lt;/em&gt; real-part eigenvalues. These correspond to &lt;em&gt;dissipative effects&lt;/em&gt;: small-scale pertubations generally are smoothed out to zero by the physical effects, e.g. winds have friction, mixing of air of different temperature averages out the differences, etc.. If you now run the simulation backwards, you turn those negative real parts into positive real parts, and that means the system is suddenly &lt;em&gt;massively chaotic&lt;/em&gt; on all length scales. Small pertubation arise out of numerical uncertainties, and grow over all bounds. You would not only end up with states different from the actual weather a week ago, but with states that are completely unlike anything the weather has ever been like – huge, erratic temperature fluctuations and small vortices with crazy wind speeds.&lt;/p&gt;&#xA;" OwnerUserId="12095" LastEditorUserId="12095" LastEditDate="2018-07-09T15:53:11.380" LastActivityDate="2018-07-09T15:53:11.380" CommentCount="17" ContentLicense="CC BY-SA 4.0" />
  <row Id="14584" PostTypeId="2" ParentId="14581" CreationDate="2018-07-09T20:49:39.397" Score="1" Body="&lt;p&gt;In a nutshell, no.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason why is because of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Butterfly_effect&quot; rel=&quot;nofollow noreferrer&quot;&gt;Butterfly Effect&lt;/a&gt;.  In a system where the current state depends on the previous state in an iterative way, you can get chaotic effects.  Chaotic effects can magnify extremely tiny inputs to gigantic changes over time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This was first noted by the excellent mathematician and meteorologist Edward Lorenz.  &lt;a href=&quot;http://www.stsci.edu/~lbradley/seminar/butterfly.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;This is a decent explanation&lt;/a&gt; of how he came to notice that the equations predicting the weather are extremely sensitive to current conditions.  You simply can't build a computer with enough sensitivity to do a good job. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since tiny fluctuations can cause huge effects over time, you have to ask yourself - how much information can your simulation encompass?  Lorenz showed that tiny things can change the entire landscape over time.  To be accurate, a simulation would have to take into account every source of small changes - sunspot activity, the wobble of the moon, the gravitational tug from Pluto...the list is endless.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So unfortunately for a chaotic system like weather, you can't predict with any accuracy previous or future states.  &lt;/p&gt;&#xA;" OwnerUserId="13312" LastActivityDate="2018-07-09T20:49:39.397" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14585" PostTypeId="2" ParentId="14581" CreationDate="2018-07-10T17:24:05.290" Score="3" Body="&lt;p&gt;A completely different approach to the one leftroundabout pointed out is to use recurrent neural networks. These were made to predict the future development of a time series by first learning the hidden model itself and then using it to guesstimate the future values. The advantage of this method is, that not even the slightest knowledge about meteorology is needed, all the modelling of the weather system is done by the algorithm training the neural network.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact there was a Kaggle competition with the task to predict rainfall from past data: &lt;a href=&quot;http://simaaron.github.io/Estimating-rainfall-from-weather-radar-readings-using-recurrent-neural-networks/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://simaaron.github.io/Estimating-rainfall-from-weather-radar-readings-using-recurrent-neural-networks/&lt;/a&gt; .&#xA;The winner used recurrent neural networks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case of predicting past values from current values the same architecture can be used, as it can learn the backward model as directly as a forward model.&lt;/p&gt;&#xA;" OwnerUserId="13318" LastEditorUserId="13318" LastEditDate="2018-07-14T09:34:22.803" LastActivityDate="2018-07-14T09:34:22.803" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14587" PostTypeId="1" CreationDate="2018-07-11T12:18:08.343" Score="42" ViewCount="145888" Body="&lt;p&gt;Lots of people have explained it over many sites but I still can not confidently say that I know what it means when they say Hong Kong experienced 3mm of rainfall last Friday.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does it mean that 3mm per square meter was experienced in a specific area, or does it mean that the total amount of rain had a volume such that if it was spread over all of Hong Kong the height would be 3mm. Or is it referred to in terms of per square meter?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the time period? Is it measured per day, per hour, per minute?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT&lt;/strong&gt;: The question marked as a duplicate may refer to some aspects of the question but does not effectively ask them. The title of the question refers to something different and the only answer to that question is what I am asking an explanation of.&lt;/p&gt;&#xA;" OwnerUserId="13323" LastEditorUserId="13323" LastEditDate="2018-07-13T06:14:34.250" LastActivityDate="2023-07-12T04:01:35.340" Title="What does a mm of rain mean?" Tags="|measurements|rainfall|rain|" AnswerCount="10" CommentCount="15" ContentLicense="CC BY-SA 4.0" />
  <row Id="14588" PostTypeId="2" ParentId="14587" CreationDate="2018-07-11T13:17:47.820" Score="22" Body="&lt;p&gt;It is the amount of rain that it takes to cover the ground X milimeters deep. It is normally measured in 24 hours and is measured each morning at a fixed time like 0900.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But now the measurements are fully automatic, so the meteorological service gets the data more often and can provide data for each hour of the day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Total rainfall is still measured from 0900 to the next day at 0900.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Link &lt;a href=&quot;http://www.bom.gov.au/climate/cdo/about/rain-measure.shtml&quot; rel=&quot;noreferrer&quot;&gt;http://www.bom.gov.au/climate/cdo/about/rain-measure.shtml&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Two weather stations with some distance between them can often give very different measurements.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="502" LastEditDate="2018-07-17T04:25:11.833" LastActivityDate="2018-07-17T04:25:11.833" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14589" PostTypeId="2" ParentId="14587" CreationDate="2018-07-11T15:57:17.160" Score="19" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Does it mean that 3mm per square meter was experienced in a specific&#xA;  area, or does it mean that the total amount of rain had a volume such&#xA;  that if it was spread over all of Hong Kong the height would be 3mm.&#xA;  Or is it referred to in terms of per square meter?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They're really the same idea.  Fundamentally it means that it filled a rain gauge (&lt;a href=&quot;https://en.wikipedia.org/wiki/Rain_gauge&quot; rel=&quot;noreferrer&quot;&gt;of some type&lt;/a&gt;) to 3mm height.  But every place that gets that experience equally would see the same amount of rain.  So if the storm hit the entirety of Hong Kong as it hit the airport, the &lt;a href=&quot;https://weather.gladstonefamily.net/site/VHHH&quot; rel=&quot;noreferrer&quot;&gt;rain gauge at that airport&lt;/a&gt; would record 3mm, and so would any other rain gauge in the city.  And (on flat, exposed ground... if water didn't absorb into the soil or evaporate over time) every square meter would get a depth of 3mm... and the region as a whole would have been covered with 3mm deep of water.  (Of course water truly flows downhill and is deflected by buildings and such, so you'd end up with much more water in some spots, less in others).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, 3mm is the height of whatever 3-dimensional &lt;a href=&quot;https://en.wikipedia.org/wiki/Prism_(geometry)&quot; rel=&quot;noreferrer&quot;&gt;prismatic shape&lt;/a&gt; you want to draw that was equally affected by the storm, be it a box with a square base of 1 m$^2$, a cylinder 1 km in diameter, a surface with a base of the entire city, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now of course in reality, not every place does experience the storm the same.  And so Hong Kong airport may get 3mm, but &lt;a href=&quot;https://weather.gladstonefamily.net/site/45044&quot; rel=&quot;noreferrer&quot;&gt;Cheung Chau&lt;/a&gt; may only see 2mm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And it's still true that a storm that affects a larger area with 3mm of rainfall does put down more total water quantity in entirety.  If the same storm hits all of China, that's indeed a lot of water!  But of course it's also a larger area to absorb that water.  So regardless of whether it's a Hong-Kong sized downpour or a China sized rain system, if it puts down 3mm, it tends to have similar impacts throughout the region affected.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As others mention, a day is a very common time period for reporting such values.  But they can be reported for whatever time periods people wish.  Often you'll hear values for a specific storm, which can be as short as a quick downpour, or as long as a multi-day typhoon/hurricane.  It's whatever the person wants to report about.  Usually they'll give the time period or subject.  3mm doesn't fall in 1 second, but &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_weather_records#Precipitation&quot; rel=&quot;noreferrer&quot;&gt;it can fall in a period much shorter than an hour&lt;/a&gt;.  Or it can be the accumulation from only a steady drizzle that lasts days.   That's where the rainfall rates (often given in mm or inches per hour) can be worthwhile!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-07-13T05:12:03.860" LastActivityDate="2018-07-13T05:12:03.860" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14590" PostTypeId="2" ParentId="14587" CreationDate="2018-07-11T17:09:08.373" Score="51" Body="&lt;p&gt;It's confusing to measure liquid in units of &lt;em&gt;length&lt;/em&gt; instead of &lt;em&gt;volume&lt;/em&gt;, isn't it? Here's how it works.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;One millimeter of rain&quot; is actually &lt;em&gt;one cubic millimeter per square millimeter&lt;/em&gt;. On average, over the area you're talking about, each square millimeter has received one cubic millimeter of rain. If you divide &lt;strong&gt;n&lt;/strong&gt; mm&lt;sup&gt;3&lt;/sup&gt; by 1 mm&lt;sup&gt;2&lt;/sup&gt;, you get -- &lt;strong&gt;n&lt;/strong&gt; mm!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The field of &lt;a href=&quot;https://en.wikipedia.org/wiki/Dimensional_analysis&quot; rel=&quot;noreferrer&quot;&gt;Dimensional Analysis&lt;/a&gt; deals with questions like this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If there was &quot;1 mm of rain&quot;, how much rain did a square meter receive? 1000 mm * 1000 mm * 1 mm = 1 000 000 mm&lt;sup&gt;3&lt;/sup&gt; = 1 liter. Pour one liter of water into a square container one meter on a side, and it forms a layer one millimeter deep.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To calculate &quot;how much rain fell on Hong Kong&quot; (expressed as &lt;em&gt;total volume&lt;/em&gt;), you'd take the area of Hong Kong, and multiply it by 1 mm. That's &lt;em&gt;usually&lt;/em&gt; not what people want to know, though -- they want to know how wet things got, and the volume-per-area number is most convenient for that.&lt;/p&gt;&#xA;" OwnerUserId="13324" LastEditorUserId="13324" LastEditDate="2018-07-15T13:13:21.437" LastActivityDate="2018-07-15T13:13:21.437" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="14591" PostTypeId="1" CreationDate="2018-07-11T14:57:01.653" Score="6" ViewCount="86" Body="&lt;p&gt;&lt;a href=&quot;https://en.m.wikipedia.org/wiki/Prediction_of_volcanic_activity&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; names thermal monitoring as one of the methods for predicting volcanic eruptions. I was able to find some papers (&lt;a href=&quot;https://www.dartmouth.edu/~volcano/BiThesis.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;First&lt;/a&gt;, &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S2214242815000029&quot; rel=&quot;nofollow noreferrer&quot;&gt;Second&lt;/a&gt;) on such thermometry and while they are challenging (I retired from physics years ago), I will consult them for the methods.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I completely fail to find information on, is how current thermal behavior is supposed to be linked to &lt;em&gt;future&lt;/em&gt; eruptions (other than: &quot;it’s getting hotter, that could be magma rising upwards&quot;). I realize we don’t have complete theories, but I hope you can tell me what kinds of ansatzes there are.&lt;/p&gt;&#xA;" OwnerUserId="13325" OwnerDisplayName="Ludi" LastEditorUserId="6465" LastEditDate="2018-07-18T08:19:45.057" LastActivityDate="2018-07-18T08:19:45.057" Title="What theories exist connecting volcano temperatures to eruption probabilities?" Tags="|geophysics|volcanology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14593" PostTypeId="2" ParentId="9651" CreationDate="2018-07-12T07:41:46.213" Score="-2" Body="&lt;p&gt;You should find what you're after within the following:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://rules.dnvgl.com/docs/pdf/DNV/codes/docs/2014-04/RP-C205.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://rules.dnvgl.com/docs/pdf/DNV/codes/docs/2014-04/RP-C205.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If not, one of their other documents should contain the information.&#xA;I hope this finds you well.&lt;/p&gt;&#xA;" OwnerUserId="13336" LastActivityDate="2018-07-12T07:41:46.213" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14595" PostTypeId="1" AcceptedAnswerId="14627" CreationDate="2018-07-12T11:13:22.747" Score="5" ViewCount="592" Body="&lt;p&gt;In analyses of mixed layer heat budget analysis, authors of different papers have considered the contribution of vertical mixing in different ways. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Ka6R8.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ka6R8.png&quot; alt=&quot;breakdown of vertical subsurface process contribution: net vertical subsurface processes (blue,&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Halkides and Lee (2011) have considered entrainment, vertical advection and vertical mixing as components of subsurface processes indicating that entrainment and vertical mixing are different processes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Foltz et a. (2010) on the other hand explain that turbulent entrainment and turbulent diffusion are processes involved in vertical turbulent mixing. This paper indicates that entrainment is a part of vertical turbulent mixing. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please explain the difference between entrainment and vertical mixing if at all they are different processes.&lt;/p&gt;&#xA;" OwnerUserId="8219" LastActivityDate="2018-07-17T08:44:42.700" Title="What is the difference between vertical turbulent entrainment and turbulent diffusion in the ocean?" Tags="|oceanography|" AnswerCount="1" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14596" PostTypeId="2" ParentId="14587" CreationDate="2018-07-12T11:59:34.680" Score="2" Body="&lt;p&gt;It means that during the rain event (which may last a minute, an hour, a day), one square meter of ground was filled with water up to a height of 3mm. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The one square meter just next to this first square meter was &lt;strong&gt;also&lt;/strong&gt; filled with a height of 3mm of water. So that over the 2 square meters united, the ground was still filled up to 3mm of water. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A surface of 10 square meters was also filled with water up to a height of 3mm, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, the volume of rain collected obviously depends on the surface of the ground, but the height of the water level fallen onto the ground does not depend on the surface of the collector. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is of course correct if the rain is uniform over the whole surface (i.e. it might brake for a surface which is much smaller than the distance between the drops, or for a surface that is larger than the scale at which the rain rate uniform).&lt;/p&gt;&#xA;" OwnerUserId="13342" LastActivityDate="2018-07-12T11:59:34.680" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14597" PostTypeId="1" AcceptedAnswerId="14885" CreationDate="2018-07-12T12:26:53.503" Score="7" ViewCount="380" Body="&lt;p&gt;I'm working on a small project and am trying to find a way to get the very extended hour-by-hour forecast for a location. Most services (Darksky, etc.) seem to offer 7-day extended hourly forecasts, but I'm not able to find anything beyond that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone have suggestions?&lt;/p&gt;&#xA;" OwnerUserId="13344" LastActivityDate="2022-01-25T22:48:58.490" Title="Are there any weather services that provide hourly forecasts beyond 7 days?" Tags="|meteorology|weather-forecasting|" AnswerCount="6" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14598" PostTypeId="2" ParentId="14597" CreationDate="2018-07-12T13:56:58.227" Score="2" Body="&lt;p&gt;No.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The atmosphere is too chaotic for hourly forecasts at time scales beyond several days to be useful.&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2018-07-12T13:56:58.227" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14599" PostTypeId="2" ParentId="14587" CreationDate="2018-07-12T14:35:51.280" Score="2" Body="&lt;p&gt;Your question seems to be a conceptual one, so I'll answer conceptually.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the sake of the argument let's imagine a flat area with impermeable ground, like rock, and an impermeable wall around it. After it has rained for some time with a certain intensity over that area &amp;mdash; everywhere the same &amp;mdash;, there will be a certain height of water on the ground, which will be the same height all over this flat area. This height is measured in millimeters and reported. You can now go and divide this area up in square meters, or soccer fields, or square milimeters; the height of the water would obviously not change. That's the beauty of this measurement: It is independent of any particular area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are unrealistically ideal assumptions. The intensity or duration differed from place to place, the ground is not level, water seeps away etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the statement actually says: &quot;This station measured a rain event which would cover any area with x mm of rain if it had rained everywhere the same amount as it did here.&quot; The duration is irrelevant with respect to the amount but must be mentioned together with the measurement because it makes a huge difference in meaning and impact: 100 mm in a month are just wet while 100 mm in a day are catastrophic. In your case, &quot;last Friday&quot;, one may assume a 24 hour calendar day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's also often not possible to make a reliable statement for a larger area, especially in the case of local severe weather events. One can make an estimation based on measurements from different stations in the area and qualitative observations, but the only reliable accurate statements which can be made are factual measurements at weather stations; everything else is inferred, as in your example about all of Hong Kong.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can imagine though that among Meterologists the sentence &quot;Hong Kong reports 3 mm of rain&quot; is taken to mean &quot;The &lt;a href=&quot;https://www.hko.gov.hk/abouthko/aboutus.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hong Kong Observatory&lt;/a&gt; reports 3 mm of rain&quot;, and equivalently for other places.&lt;/p&gt;&#xA;" OwnerUserId="5396" LastEditorUserId="5396" LastEditDate="2018-07-16T08:52:58.257" LastActivityDate="2018-07-16T08:52:58.257" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14600" PostTypeId="2" ParentId="14597" CreationDate="2018-07-12T15:19:23.747" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://www.ecmwf.int/en/forecasts/charts/catalogue/?facets=Range,Medium%20(15%20days)&quot; rel=&quot;nofollow noreferrer&quot;&gt;ECMWF&lt;/a&gt; (European Centre for Medium-Range Weather Forecasts) provides global forecast to member organizations and probably there is a way to obtain their hourly forecast up to 15 days. They provide average fields to the public, but the hourly data is not available that way. You can contact them directly and ask them about availability.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2018-07-12T15:19:23.747" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14602" PostTypeId="2" ParentId="14597" CreationDate="2018-07-12T17:40:43.673" Score="4" Body="&lt;p&gt;&lt;a href=&quot;http://wwwl.accuweather.com/premium_forecast_benefits.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Accuweather Premium&lt;/a&gt; claims 15 days of hourly forecasts.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.zazzle.com/cute_pattern_weather_dart_board-256665018944132042&quot; rel=&quot;nofollow noreferrer&quot;&gt;This&lt;/a&gt; may be just as good though.&lt;/p&gt;&#xA;" OwnerUserId="8163" LastActivityDate="2018-07-12T17:40:43.673" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14603" PostTypeId="2" ParentId="14597" CreationDate="2018-07-12T18:05:59.313" Score="8" Body="&lt;p&gt;The trouble is, any skill above climatology beyond about 5-7 days is very very low.&lt;/p&gt;&#xA;&lt;p&gt;So sites could offer such forecasts, but they wouldn't be worth much of anything.&lt;/p&gt;&#xA;&lt;p&gt;The main thing they could offer that has any use that is an indication of what typically happened in previous years (i.e. climatology)... but unfortunately I don't know any site that offers such on an hourly basis.  We could use more of that!  Still, if you're familiar with the area you're looking up for, you're probably fairly used to the typical weather for a given time of year.&lt;/p&gt;&#xA;&lt;p&gt;There has been some &lt;a href=&quot;http://www.cpc.ncep.noaa.gov/products/verification/summary/&quot; rel=&quot;nofollow noreferrer&quot;&gt;small skill&lt;/a&gt; at making blurrier longer range forecasts... basically estimating either within a large range (such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_cyclone_seasonal_forecasting&quot; rel=&quot;nofollow noreferrer&quot;&gt;hurricane forecasts&lt;/a&gt;) or (more often) giving probabilities of whether the weather will be above or below that climatological expectations.&lt;br /&gt;&#xA;For more about the very limited skill of week 2 forecasts, see &lt;a href=&quot;https://earthscience.stackexchange.com/questions/22385/how-accurate-is-the-national-weather-service-8-to-14-day-outlook/23280#23280&quot;&gt;this answer&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;But such long-range forecasts don't have nearly the precision to offer hourly forecasts to be of any legitimate use.  It'd be like saying it'll take you 46 minutes and 7 seconds to get to work two weeks from Thursday... entirely misleading specificity.&lt;/p&gt;&#xA;&lt;p&gt;So basically if you're eagerly planning for a trip in 10 days or a wedding in a month or two, you're much better off staying far away from such &lt;a href=&quot;https://weather.com/weather/monthly/l/Orlando+FL+USFL0372:1:US&quot; rel=&quot;nofollow noreferrer&quot;&gt;novelty longrange forecasts&lt;/a&gt; until the event gets much closer.  Until then, all you can really figure on is what's typical for the given time of year.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-01-25T22:48:58.490" LastActivityDate="2022-01-25T22:48:58.490" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14604" PostTypeId="2" ParentId="14587" CreationDate="2018-07-12T21:14:17.660" Score="5" Body="&lt;p&gt;Simply, an &quot;amount&quot; of rain is a certain &lt;em&gt;volume&lt;/em&gt;, and volume equals area x height.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;3mm of rain&quot; means for &lt;em&gt;any&lt;/em&gt; given area, the amount of rain that fell (ie the volume) would fill that area to a height of 3mm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;em&gt;area&lt;/em&gt; part of the formula is effectively a constant. The only variable is the height.&lt;/p&gt;&#xA;" OwnerUserId="1290" LastActivityDate="2018-07-12T21:14:17.660" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14605" PostTypeId="2" ParentId="14587" CreationDate="2018-07-13T00:37:37.773" Score="10" Body="&lt;p&gt;Given any container with straight sides, 3 millimeters of rainfall will fill up that container to 3 millimeters in depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The size of the container does not affect this.  It holds whether the container is the size of a tennis court, or the size of a small beaker or a test tube with a flat bottom.  As long as its sides are vertical and uniform.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is also not necessary to talk about &lt;em&gt;volume&lt;/em&gt; of water (eg cubic millimeters, liters etc) to understand this.  You would only be converting to volume in order to convert back to depth later.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All you need to take into account is that any straight edged container will fill to this depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;If you ever see a conical shaped container measuring rainfall, it's because the depth measurements on the side of that container are non-linear - these markings show what the equivalent depth would be in a straight-edged container&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Note 2: shallow water evaporates relatively quickly. For a rain gauge to be useful it needs to have a way to minimise evaporation, such as by having a funnel in the top.  The area of the top of the funnel still matches the cross sectional area of the container in which we're measuring the depth&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="13351" LastActivityDate="2018-07-13T00:37:37.773" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14606" PostTypeId="2" ParentId="14597" CreationDate="2018-07-13T02:05:21.133" Score="6" Body="&lt;p&gt;&lt;a href=&quot;https://www.wunderground.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weather Underground&lt;/a&gt; and &lt;a href=&quot;http://www.intellicast.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;Intellicast&lt;/a&gt; provide ten day forecasts in a beautiful (to a nerdy engineer) graphical format, in hourly increments. The skill in the last two to five days of those extended forecasts is suspect.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="543" LastEditDate="2018-07-13T03:46:01.220" LastActivityDate="2018-07-13T03:46:01.220" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14607" PostTypeId="1" CreationDate="2018-07-13T13:02:26.153" Score="14" ViewCount="4147" Body="&lt;p&gt;According to wikipedia, the Earth is about 4.543 billion years old. If I understand correctly, this number is based on radiometric age-dating of meteorites. So basically, the logic is this:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;We've got this material&lt;/li&gt;&#xA;&lt;li&gt;We can show that it's about 4.543 billion years old&lt;/li&gt;&#xA;&lt;li&gt;We haven't found anything older.&lt;/li&gt;&#xA;&lt;li&gt;Therefore this is probably about the age of the Earth&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;However inference 4 seems a bit problematic. How do we know that the Earth isn't significantly older? Could it be 5 billion years old? Could it be 8? Discounting the big bang theory, could it be 13 or even 15 billion years old, using only what we know about the science of the Earth?&lt;/p&gt;&#xA;" OwnerUserId="13358" LastEditorUserId="13358" LastEditDate="2018-07-15T07:32:59.190" LastActivityDate="2018-07-16T19:38:20.310" Title="Could the earth be much older than the currently accepted number?" Tags="|earth-history|age|" AnswerCount="5" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="14608" PostTypeId="2" ParentId="14607" CreationDate="2018-07-13T13:15:44.367" Score="14" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Formation_and_evolution_of_the_Solar_System&quot; rel=&quot;noreferrer&quot;&gt;age of the solar system&lt;/a&gt; is 4.6 billion years.  We know that because almost all meteorites are 4.6 billion years old¹.  Therefore, that puts a very solid upper boundary to the age of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to solar system models, it took between 10 million and 100 million years for the Earth to form in the early Solar System.  That result is consistent with the independently estimated age of the Earth of 4.54 billion years old.  The Earth could maybe be 10 million years older, but it certainly couldn't be older than the solar system.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;None are older.  We've never found a meteorite from outside the solar system.  I expect some scientists would have given an arm and a leg for the opportunity to sample some rocks from interstellar &lt;a href=&quot;https://en.wikipedia.org/wiki/%CA%BBOumuamua&quot; rel=&quot;noreferrer&quot;&gt;Oumuamua&lt;/a&gt; but it was not possible.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2018-07-13T17:41:39.303" LastActivityDate="2018-07-13T17:41:39.303" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14610" PostTypeId="1" CreationDate="2018-07-13T16:05:46.760" Score="1" ViewCount="37" Body="&lt;p&gt;I have some ALOS palsar SLC data products which are downloaded from ESA database and they are processed with ESA ALOS-PALSAR IPF processor which is different from JAXA. Formerly it was not possible to load these datatype to SNAP but newly after some updates SNAP is useful to load and use the mentioned data. &#xA;The main question is that &quot;How can I use ALOS PALSAR SLC data for geologic mapping based on the difference of geologic units to RADAR waves and different backscatters?&quot;.&#xA;Any Idea to combine spectral data (ie.ETM and ASTER) and SAR data to improve the geological mapping process?&lt;/p&gt;&#xA;" OwnerUserId="13361" LastActivityDate="2018-07-13T16:05:46.760" Title="ALOS Palsar SLC data products for geological mapping" Tags="|geology|structural-geology|data-analysis|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14611" PostTypeId="2" ParentId="14607" CreationDate="2018-07-13T22:27:01.853" Score="3" Body="&lt;p&gt;From &lt;a href=&quot;https://www.amnh.org/explore/resource-collections/earth-inside-and-out/zircon-chronology-dating-the-oldest-material-on-earth/&quot; rel=&quot;nofollow noreferrer&quot;&gt;zircon dating&lt;/a&gt; we know that the age of the earth is close to the age of the asteroids in our solar system (i.e. there is not a huge discrepancy between their ages). Without evidence indicating otherwise, scientist are left with no other conclusion but that the asteroids and the earth are of nearly the same age.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastEditorUserId="2959" LastEditDate="2018-07-14T19:16:48.003" LastActivityDate="2018-07-14T19:16:48.003" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14612" PostTypeId="2" ParentId="14607" CreationDate="2018-07-14T02:07:17.537" Score="2" Body="&lt;p&gt;Claire Patterson et al settled the Age of the Earth in 1956.  In this paper, which can be obtained for free from &lt;a href=&quot;https://www.colorado.edu/geolsci/courses/GEOL5700-9/pdf/Fall07/Patterson.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Colorado.edu&lt;/a&gt;, we read:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;The following assumptions are made concerning meteorites: they were formed at the same time; they existed as isolated and closed systems; they originally contained lead of the same isotopic composition; they contain uranium which has the same isotopic composition as that of the earth.&quot; (&lt;a href=&quot;https://www.colorado.edu/geolsci/courses/GEOL5700-9/pdf/Fall07/Patterson.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;p.1&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;...and...&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;If the earth is a late agglomeration without differentiation of meteoritic material then it can have any age less than meteoric material.  Rather than arguing that such a process would be accompanied by chemical differentiation (and a change of the U/Pb ratio), it seems reasonable to believe instead that such a late agglomeration process would be less probable than one where both meteorites and the earth were formed at the same time. It is a fact that extreme chemical differentiation occurred during the process which led to the mechanical isolation of the mass of material of which the earth is made, and since changes in this mass were accompanied by chemical differentiation, the Pb/Pb isochron age properly refers to the time since the earth attained its present mass.&quot; (&lt;a href=&quot;https://www.colorado.edu/geolsci/courses/GEOL5700-9/pdf/Fall07/Patterson.pdf#page=7&quot; rel=&quot;nofollow noreferrer&quot;&gt;p.7&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The present age of the earth, then, is calculated upon an astronomical model which asserts that the formation of the solar system happened in the way we believe it did, which results in our assertion that measurements taken on meteorites apply to the earth as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Contrasted against meteorites, zircons are a nice earth-bound reference because unlike everything else in the earth's crust, we do not believe that they give falsely young readings due to the crust's constant re-melting and cooling (zircons are hard to re-melt).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the earth really were older than the meteorites and zircons are telling us, then its long early history was probably inhospitable to life due to our observation that no zircons have been found that are older: it would have been crazy hot during that time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's worth noting that radiometric methods are the only methods that give an affirmative earth age greater than 0.05 million years: the ice core layers are only dated beyond that age according to curve fitting, not layer counting.&lt;/p&gt;&#xA;" OwnerUserId="13373" LastActivityDate="2018-07-14T02:07:17.537" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14613" PostTypeId="2" ParentId="14607" CreationDate="2018-07-14T06:37:55.150" Score="3" Body="&lt;p&gt;The ages are not the only piece of information that we have. Gerrit covered most of the age issue in his answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To summarise: We know the age of the solar system (4.5-4.6) and the oldest material we have on earth is 4.4.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To add to that, we know that the composition of the Earth is very similar to what we would expect from having formed in the solar system. If the Earth was here from before that, why would it have the same composition? Therefore, we have to conclude the the Earth formed together with the solar system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, there is some chance that Earth is older and just happens to be in the composition similar to the rest of the solar system, but we have no reason to believe this is the case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is similar to pink elephants. How do you prove that they do not exist?&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-07-14T06:37:55.150" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14617" PostTypeId="2" ParentId="14591" CreationDate="2018-07-14T16:11:35.960" Score="4" Body="&lt;p&gt;I have not heard of complete theories connecting volcano temperatures to eruption possibilities either. If you mean subsurface magma temperatures, it is uncommon for there to be direct observations / readings for a particular volcano. Fumarolic temperatures, on the other hand, are directly indicative of current volcanic activity and are much more easily measured (&lt;a href=&quot;http://data.nistep.go.jp/dspace/bitstream/11035/2812/1/NISTEP-STT032E-85.pdf&quot; rel=&quot;noreferrer&quot;&gt;example&lt;/a&gt;). In addition, geochemical analysis of fumarolic gases can be related to eruption probability (&lt;a href=&quot;https://link.springer.com/article/10.1007%2FBF02596951&quot; rel=&quot;noreferrer&quot;&gt;example&lt;/a&gt;, &lt;a href=&quot;https://link.springer.com/article/10.1007%2FBF02596949&quot; rel=&quot;noreferrer&quot;&gt;example&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even in models of magma ascent, temperature differences are not the main focus, but rather pressure differences are (&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0012821X17306556&quot; rel=&quot;noreferrer&quot;&gt;example&lt;/a&gt;). This is directly related to g.z.'s comment that volatile content certainly can be a dominant eruptive trigger.&lt;/p&gt;&#xA;" OwnerUserId="13334" LastActivityDate="2018-07-14T16:11:35.960" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14621" PostTypeId="2" ParentId="14587" CreationDate="2018-07-15T13:15:55.577" Score="2" Body="&lt;p&gt;Rainfall is measured with a rain gauge. This one goes up to 12 cm or 120 mm, so 3 mm would just be a few drops at the bottom.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/krrrG.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/krrrG.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can imagine, it doesn't matter how big this gauge is, as long as the sides are straight. A larger cylinder will hold more water, but it has a larger opening to collect rain, so the measured rainfall is the same in either case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Inversely, multiplying the rainfall (3 mm) by an area (100 square meters) gives a volume (= 0.3 cubic meters, or 300 liters), assuming a uniform rainfall over the area.&lt;/p&gt;&#xA;" OwnerUserId="11490" LastActivityDate="2018-07-15T13:15:55.577" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14624" PostTypeId="2" ParentId="14587" CreationDate="2018-07-16T05:11:18.917" Score="2" Body="&lt;p&gt;I will address the aspects of the question that relate to how rainfall is measured and the measurement period. Some of this has been mentioned in other answers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As previously noted you can think the amount of rain as the volume of water that falls on a given area divided by that surface area. That means that the measurement has units of length (typically mm). This assumes that the amount you measure at one point can represent the amount that falls over the whole area or that you measure many points that represent different parts of a large area and add them together. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The straight-sided graduated cylinders discussed in other answers have a constant area so the depth markings are a constant (1 mm) apart, but you can use other shapes, if they are marked correctly, to show what the depth &lt;em&gt;would be&lt;/em&gt; on a straight sided cylinder. One common design is to have a funnel with a large area at the top feed into a narrower container below. In that case the depth of the water captured will be greater than the rainfall in mm. These take the rain volume from a larger area and measure it in a smaller one because it 'magnifies' the depth, making it easier to read for small amounts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Rain_gauge&quot; rel=&quot;nofollow noreferrer&quot;&gt;Automated systems work differently, using weighing or 'tipping bucket' systems.&lt;/a&gt; Tipping buckets have a funnel like top that feeds the water down into little cups on a pivot below. When one cup fills up the weight causes it to go down like a see-saw and the bucket empties. The other bucket moves up and catches the water until it is full and goes down. They are designed so the weight of rain it takes to get the tipping bucket to pivot is known. All you have to do is count how many times it pivots to measure the rainfall. If you assume that rain is essentially pure water, then the weight is directly related to the volume. Divide that volume by the area of the top of the gauge and you get mm of rain. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sU8Vk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sU8Vk.png&quot; alt=&quot;Looking down onto a tipping-bucket rain gauge&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/22F24.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/22F24.png&quot; alt=&quot;Interior of tipping-bucket rain gauge&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most country's weather services report the amount of rain over a day and add the amounts together to get monthly or annual measurements, but it is possible to take measurements more frequently. More frequent measurements can be used to report rainfall intensity over a shorter period. So you, for example, could report the maximum hourly rainfall intensity within a day. You can also use more frequent measurements to calculate how quickly streamflow responds to a rainstorm.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2018-07-16T05:11:18.917" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14625" PostTypeId="2" ParentId="14607" CreationDate="2018-07-16T19:38:20.310" Score="3" Body="&lt;p&gt;The chances of this actually being accurate are remote to the extreme, but Earth could in theory be a captured planet older than the solar system, and the resurfacing from the giant impact removed all the evidence.     First, captured rogue planets with stable orbits in the inner solar system are virtually impossible.    Second, the timing would need to be nearly perfect where the capture happened when the solar system was very young.   So, I don't like this idea.  It's so unlikely as to be preposterous.   But it's theoretically possible that the Earth is older than the solar system, if it was an older rogue planet that somehow got captured, perhaps by gravity assist around baby-Jupiter and stabilized over time by collisions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question asked if it was possible, and I see no reason why this wouldn't be possible.   So unlikely it's not worth considering - yes, very much yes.  But not, to my knowledge, impossible. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now as to 15 billion years old?   Older than the Universe.   Lets just say no and leave it at that, unless you want to debate that the estimates to the age of the Universe are wrong, and that's Cosmology, not Earth Science.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2018-07-16T19:38:20.310" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14627" PostTypeId="2" ParentId="14595" CreationDate="2018-07-17T08:44:42.700" Score="6" Body="&lt;p&gt;I would say that different authors might want to distinguish deep convective mixing with entrainment from purely diffusive or gravity wave-driven mixing. Deep mixing occurs mainly within certain zones (around Antarctica, and in the Labrador sea) because it requires a very strong cooling of the surface to trigger convection. Diffusive or gravity wave-breaking mixing can occur anywhere. Diffusion could include direct processes (like double-diffusion or &quot;salt fingering&quot;) or indirect processes such as cabbeling or thermobaricity. If their budgets are based on models, these classes of processes are likely output separately anyway, so it's an easy division to make.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would break it down as follows, with an eye toward model output:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Vertical advection comes from the advection by &lt;em&gt;resolved or implied&lt;/em&gt; vertical velocity. This would include Ekman pumping and any other vertical velocity you might get from an omega-equation.&lt;/li&gt;&#xA;&lt;li&gt;Entrainment-detrainment comes from convective processes. These require special handling, since many ocean models until recently would not resolve these processes. (They might occur in areas that are only a few kilometers in width, far below the lateral resolution.) These processes can mix together entire parts of the water column at once and often do not care about vertical gradients; they are &quot;non-local&quot;.&lt;/li&gt;&#xA;&lt;li&gt;Diffusive processes are very local/small-scale and depend on vertical gradients of heat and salt. Cabbeling, thermobaricity, and double diffusion are some examples. I include gravity wave-driven mixing here because although the gravity wave generation process is non-local, when they break they can only mix locally within the water column.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;This kind of breakdown makes sense for a global ocean model, where these three things are handled by three separate modules. For super-hi-res regional models and non-hydrostatic models, advection and convection start to merge together, and if the model is truly eddy-resolving, entrainment becomes a mix of advection followed by diffusion. How you budget these processes depends on the spatial and temporal scales of the model. &lt;/p&gt;&#xA;" OwnerUserId="1342" LastActivityDate="2018-07-17T08:44:42.700" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14632" PostTypeId="1" CreationDate="2018-07-18T11:09:14.750" Score="1" ViewCount="66" Body="&lt;p&gt;I had burnt my finger by digging an empty well and spending my hard-earned money in vain. I then started to study about the resistivity method for finding underground details. But I have many doubts arised now. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the resistivity of ground water in ohm-m.&#xA;How to find the exact depth at which the water is starting.&#xA;Is there any good tutorial to learn more of geophysics.&#xA;Is there any good open source software to map the underground water and tutorial for it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit:&#xA;Thanks for the response, iam from southern part of India. My city is called as Chennai. We have Wells nearby.&lt;/p&gt;&#xA;" OwnerUserId="13401" LastEditorUserId="13401" LastEditDate="2018-07-25T14:25:37.200" LastActivityDate="2018-07-25T14:25:37.200" Title="Easiest way to find the water table under my feet" Tags="|geophysics|water|underground-water|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14633" PostTypeId="5" CreationDate="2018-07-18T15:06:45.947" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2018-07-18T15:06:45.947" LastActivityDate="2018-07-18T15:06:45.947" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14634" PostTypeId="4" CreationDate="2018-07-18T15:06:45.947" Score="0" Body="Geodesy is the science of accurately measuring and understanding three fundamental properties of the Earth: its geometric shape, its orientation in space, and its gravity field  as well as the changes of these properties with time." OwnerUserId="13402" LastEditorUserId="13402" LastEditDate="2018-07-19T10:40:33.717" LastActivityDate="2018-07-19T10:40:33.717" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14641" PostTypeId="1" CreationDate="2018-07-19T02:17:49.120" Score="4" ViewCount="511" Body="&lt;p&gt;I think that if you touch an aurora it will give you radiation damage? But then the solar winds at -90C would freeze you, so speaking metaphorically what would happen?&lt;/p&gt;&#xA;" OwnerUserId="13407" LastEditorUserId="13407" LastEditDate="2018-07-19T10:50:16.523" LastActivityDate="2018-08-19T18:37:37.637" Title="What would happen if you hypothetically happened to touch an aurora" Tags="|planetary-science|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14642" PostTypeId="1" CreationDate="2018-07-19T07:04:21.657" Score="5" ViewCount="458" Body="&lt;p&gt;To model hydrology in a watershed, two of the most famous and widely used distributed models are SWAT and HSPF. I have some good understanding of HPSF, but I don't know when and why should one prefer one over the other. HSPF can simulate with a timestep of 1 minute. I have already heard that SWAT is mostly used for agricultural areas. What I want to know that what is the basic difference between these two models in terms of the processes they model?&lt;/p&gt;&#xA;" OwnerUserId="5557" LastActivityDate="2018-09-15T15:14:56.913" Title="Comparing Pros and Cons of SWAT and HSPF" Tags="|hydrology|models|water|watershed|runoff|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14644" PostTypeId="1" AcceptedAnswerId="14648" CreationDate="2018-07-20T07:03:54.360" Score="2" ViewCount="69" Body="&lt;p&gt;Yesterday Katie Mack (an astrophysicist) tweeted &lt;a href=&quot;https://twitter.com/AstroKatie/status/1019936420851605504&quot; rel=&quot;nofollow noreferrer&quot;&gt;this parallel&lt;/a&gt; between a dust storm on Mars and a storm shown in the movie &quot;Mad Max Fury Road&quot; (she says &quot;Can’t help imagining that this is what that Mad Max: Fury Road scene would have looked like from above.&quot;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This made me ask: is the movie-storm a realistic storm? If yes, under which conditions?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In particular, what caught my attention is the shape of the cross-section of the advancing storm, with dust protruding on the bottom and clouds protruding on the top at the same time. Could it happen?&lt;/p&gt;&#xA;" OwnerUserId="10831" LastActivityDate="2018-08-19T12:00:53.073" Title="Under which conditions is this a realistic representation of a storm?" Tags="|extreme-weather|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14647" PostTypeId="2" ParentId="14641" CreationDate="2018-07-20T10:33:43.293" Score="1" Body="&lt;p&gt;Assuming that you have found a safe way to be at the right altitude to try to touch an aurora... I'm pretty sure that nothing much would happen. &#xA;I doubt that you could actually see it from so close, and you wouldn't feel anything if you &quot;touched&quot; it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;By dint of how high you were, and that there was a strong solar wind, you would be receiving a higher dose of ionising radiation than you would on earth. If you didn't have appropriate shielding you wouldn't want to be there for long.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2018-07-20T10:33:43.293" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14648" PostTypeId="2" ParentId="14644" CreationDate="2018-07-20T11:47:45.820" Score="2" Body="&lt;p&gt;Fury Road storm seems like quite a realistic representation of a huge thunderstorm advancing over a desert. The gust front would lift the sand in the bottom ahead of the storm center. Winds inside the storm would diverge at a higher altitude causing the sand to fall ahead of the actual storm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In reality thunderstorms do produce dust storms with their gust fronts, but there isn't as visible upper part as in the screenshot of the film. This is because the storm is moving so fast that the dust hasn't had time to get lifted up and blown forwards from above. Such storm should have very slow speed advancing on average and large updrafts lifting dust efficiently upwards. And perhaps the dust is very fine so that it acts like gas and gets easily advected.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The situation is similar to an actual cumulonimbus/thunderstorm where the top and the bottom of the cloud are pronounced. See illustration of a cumulonimbus &lt;a href=&quot;http://www.hko.gov.hk/m/article_e.htm?title=ele_00464&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6465" LastActivityDate="2018-07-20T11:47:45.820" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14650" PostTypeId="1" CreationDate="2018-07-20T16:53:15.017" Score="0" ViewCount="1432" Body="&lt;p&gt;&lt;em&gt;(Question moved from physics to earth science)&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has the earth’s atmosphere reached an equilibrium at which the input radiation energy roughly equals its output, or is the output significantly lower than the input because the energy is being used to heat up stuff? In other words – if the atmosphere’s composition remains exactly the same as it is now, will the atmosphere continue getting warmer, or will the temperature remain as it is now? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If Chuck Norris removed all man- and cow-made greenhouse gases from the atmosphere in an instant – would the atmospheric temperature return to &quot;normal&quot; in a few years, or would there be a significant lag due to the high heat capacity of atmosphere, oceans, and land?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edits to make my question more precise are appreciated.&lt;/p&gt;&#xA;" OwnerUserId="9538" LastActivityDate="2018-07-20T21:02:45.550" Title="In terms of the greenhouse effect, what is the Earth's heat capacity?" Tags="|climate-change|methane|radiation-balance|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14652" PostTypeId="2" ParentId="14650" CreationDate="2018-07-20T21:02:45.550" Score="-1" Body="&lt;p&gt;For the greenhouse effect, the problem is not a matter of heat capacity. For example, Carbon Dioxide has a &lt;a href=&quot;http://www.wolframalpha.com/input/?i=heat%20capacity%20of%20carbon%20dioxide&quot; rel=&quot;nofollow noreferrer&quot;&gt;specific heat capacity of 0.843 J g$^{-1}$ K$^{-1}$&lt;/a&gt; while $\ce{N_2}$, which is the largest component of the atmosphere, has a &lt;a href=&quot;http://www.wolframalpha.com/input/?i=heat%20capacity%20of%20dinitrogen&quot; rel=&quot;nofollow noreferrer&quot;&gt;specific heat capacity of 1.039 J g$^{-1}$ K$^{-1}$&lt;/a&gt; and water vapor, the most common greenhouse gas on earth, has a &lt;a href=&quot;http://www.wolframalpha.com/input/?i=heat%20capacity%20of%20water%20vapor&quot; rel=&quot;nofollow noreferrer&quot;&gt;specific heat capacity of 1.865 J g$^{-1}$ K$^{-1}$&lt;/a&gt;. Thus, the warming isn't necessarily a thermodynamic problem, with regards to heat capacity (though it is, in a ways, a problem of entropy).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason that some gases are greenhouse gases is more of a radiative transfer problem than a thermodynamic problem, but the two overlay with regards to molecular structure. &lt;a href=&quot;https://en.wikipedia.org/wiki/Electromagnetic_absorption_by_water&quot; rel=&quot;nofollow noreferrer&quot;&gt;Water vapor's absorption spectrum&lt;/a&gt; shows that it absorbs most infrared radiation. &lt;a href=&quot;https://www.google.com/search?q=radiation%20absorption%20carbon%20dioxide&amp;amp;rlz=1C1GGRV_enUS778US778&amp;amp;source=lnms&amp;amp;tbm=isch&amp;amp;sa=X&amp;amp;ved=0ahUKEwjcx_PmxK7cAhVpUN8KHWWHAkUQ_AUICygC&amp;amp;biw=1920&amp;amp;bih=947#imgrc=oJSWW8Hq-bIPlM:&quot; rel=&quot;nofollow noreferrer&quot;&gt;This graphic&lt;/a&gt; demonstrates how much radiation of each wavelength is absorbed by different gases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You may ask &quot;well, that's dandy, but why do some gases absorb only some parts of the spectra?&quot; Well, that is a bit more complicated, and is dependent on the molecular structure, quantum mechanics, and spectroscopy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer your hypothetical questions directly:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Has the earth’s atmosphere reached an equilibrium at which the input radiation energy roughly equals its output, or is the output significantly lower than the input because the energy is being used to heat up stuff?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In a ways, yes, that is a fundamental assumption, per &lt;a href=&quot;https://en.wikipedia.org/wiki/Kirchhoff%27s_law_of_thermal_radiation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kirchoff's law&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;if the atmosphere’s composition remains exactly the same as it is now, will the atmosphere continue getting warmer, or will the temperature remain as it is now?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There would be a lag before major changes are seen, per &lt;a href=&quot;https://fenix.tecnico.ulisboa.pt/downloadFile/3779571956902/transp3.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fourier's law&lt;/a&gt;. But since water vapor is a greenhouse gas, we would do best not to deus ex machina all greenhouse gases away. Additionally, we need greenhouse gases for survival- too little and we all freeze.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Has the earth’s atmosphere reached an equilibrium at which the input&#xA;  radiation energy roughly equals its output, or is the output&#xA;  significantly lower than the input because the energy is being used to&#xA;  heat up stuff?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Well, we are almost always at some sort of radiative equalibrium, per &lt;a href=&quot;https://en.wikipedia.org/wiki/Kirchhoff%27s_law_of_thermal_radiation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kirchoff's law&lt;/a&gt;. For example, the hotter an object becomes, the faster it will cool, per &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stefan-Boltzmann Law&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2018-07-20T21:02:45.550" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14653" PostTypeId="1" CreationDate="2018-07-20T21:23:19.690" Score="2" ViewCount="157" Body="&lt;p&gt;I would like to attempt to build a well-type structure in a woodland area. This woodland is mainly inhabited with Silver Birch and Sycamores and there is a shallow stream running down off of a moorland around 80ft from where the well would be ideally placed, but this can move.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My thoughts are that due to the prevalence of water there is likely to be a body of water underneath the ground simply through the natural process of infiltration.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my questions are the following:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Am I likely to come across water if I dug this well?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) How deep will I have to dig before I reach water or impermeable ground?&lt;/p&gt;&#xA;" OwnerUserId="13416" LastEditorUserId="106" LastEditDate="2018-08-17T10:58:57.180" LastActivityDate="2018-09-16T21:36:45.390" Title="Searching for ground water" Tags="|hydrology|water|groundwater|water-table|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14654" PostTypeId="1" CreationDate="2018-07-21T07:14:30.147" Score="5" ViewCount="2146" Body="&lt;p&gt;I live in a city where the water supply quality seem pretty good on daily/average basis. However, it is also well known that there is a huge problem with deteriorating water pipes. My problem is that every now and then, there is a very light and brief smell of &lt;em&gt;hydrocarbons&lt;/em&gt; coming from the drinkable tap water. I say &lt;em&gt;hydrocarbons&lt;/em&gt;, because it smells a bit like what you smell at a petrol/gas station. But in reality, don't know what it is. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;How can I test my water myself for hydrocarbon presence?&lt;/strong&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Where can I obtain such a test without having to spend a fortune on expensive equipment or buying &quot;testing services&quot;?&lt;/strong&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;EDIT: 2018-07-25&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found a company that offers &lt;a href=&quot;https://mytapscore.com/collections/targeted-testing-packages&quot; rel=&quot;nofollow noreferrer&quot;&gt;various test kits&lt;/a&gt; two of which may be used to find &lt;em&gt;petroleum-like&lt;/em&gt; contaminants. Unfortunately these tests are rather expensive.&lt;/p&gt;&#xA;" OwnerUserId="13420" LastEditorUserId="13420" LastEditDate="2018-07-25T08:37:52.020" LastActivityDate="2020-09-14T19:44:23.897" Title="How can I test my house water supply for hydrocarbon presence?" Tags="|petroleum|diy|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14655" PostTypeId="2" ParentId="14654" CreationDate="2018-07-21T08:43:18.650" Score="3" Body="&lt;p&gt;This question might be better suited for Chemistry or another place, and I'm not certain Earth Science is the place for it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Without being an expert on groundwater, water supplies, or hydrocarbons I would say this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First of all, &quot;deteriorating water pipes&quot; should not lead to any smell. Certain trace metals may be leached from metal (mostly copper) tubing, but you will not smell them. Plastic tubing (mostly PVC) likewise does not cause any smell.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What you are smelling could either come from the water supply itself, and then it's a municipal problem. Hydrocarbon contamination of wells or aquifers maybe? Have you raised your concerns with your local water supplier? Are you the only one who notices this, or do you neighbours witness this as well?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Testing it yourself would be hard. If the concentrations are high enough, you could ignite them. A safer way would be to pour the water to a bottle. Do you see any oily film on top? Does this change when you refrigerate the water? When you freeze the water?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fact that you smell it, means it is already volatilising out of the water when you open the tap, so whatever sample you take of the water will underestimate the hydrocarbon contents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You should also consider the fact that it's not coming from the water. Possible that it's coming from the outside, and it just happens to occur (or you notice it) when you open the tap.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-07-21T08:43:18.650" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14660" PostTypeId="1" CreationDate="2018-07-21T20:40:56.473" Score="1" ViewCount="33" Body="&lt;p&gt;What is the most effective way to study global warming and the role of greenhouse gases using a methodology based on analyzing the Earth's seasonal variations (summer-winter) of the temperature of surface air? &lt;/p&gt;&#xA;" OwnerUserId="13424" LastActivityDate="2018-07-21T20:40:56.473" Title="Relationship between Earth's heat dispersion rate (average surface air temperature from summer to winter time) and greenhouse gases" Tags="|climate-change|" AnswerCount="0" CommentCount="2" ClosedDate="2019-12-03T07:13:51.197" ContentLicense="CC BY-SA 4.0" />
  <row Id="14661" PostTypeId="1" CreationDate="2018-07-22T00:40:04.640" Score="6" ViewCount="474" Body="&lt;p&gt;What is the exact difference between regression and correlation maps?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that they are often used in climate science but which is the difference in the information they provide? Here an example I found online:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HI3Gw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HI3Gw.jpg&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the regression map between two quantities &lt;span class=&quot;math-container&quot;&gt;$A(t)$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$B(x,y,t)$&lt;/span&gt;, the map of the following index:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$r = \frac{corr( A(t), B(x,y,t) )}{var( A(t) )}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;while the correlation simply the map of&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$corr(A(t), B(x,y,t))$$&lt;/span&gt; ?&lt;/p&gt;&#xA;" OwnerUserId="6001" LastEditorUserId="106" LastEditDate="2019-04-17T11:45:25.953" LastActivityDate="2019-04-17T11:45:25.953" Title="regression map vs correlation map" Tags="|atmosphere|climate|oceanography|statistics|mathematics|" AnswerCount="0" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14662" PostTypeId="1" CreationDate="2018-07-22T06:26:48.257" Score="8" ViewCount="408" Body="&lt;p&gt;I have an NASA &lt;a href=&quot;http://theinspireproject.org/default.asp?contentID=1&quot; rel=&quot;noreferrer&quot;&gt;Inspire VLF-3&lt;/a&gt; radio receiver kit that I'm going to put together. It amplifies VLF electromagnetic signals that are already in the audio frequency range and makes them audible. One of the interesting things that it may make audible are VLF &lt;a href=&quot;https://en.wikipedia.org/wiki/Whistler_(radio)&quot; rel=&quot;noreferrer&quot;&gt;whistlers&lt;/a&gt;, signals that are triggered by lightning strikes and produced by the response of charged particles in the ionosphere orbiting around lines of the Earth's magnetic field.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that there are both spacecraft and ground stations that detect and report lightning activity, but are there websites where I can get &quot;lightning frequency maps&quot; in near-real time (worldwide)?  I live in Asia near 25 N latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've asked separately &lt;a href=&quot;https://space.stackexchange.com/q/29609/12102&quot;&gt;What are the optimal times and conditions to listen for whistlers?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/88r8t.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/88r8tm.jpg&quot; alt=&quot;NASA Inspire VLF-3&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Click for full size.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2018-09-13T15:54:03.797" Title="Are there websites where I can get &quot;lightning frequency maps&quot; in near-real time (worldwide)?" Tags="|meteorology|lightning|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14663" PostTypeId="2" ParentId="14662" CreationDate="2018-07-22T07:53:02.657" Score="5" Body="&lt;p&gt;Absolutely: The &lt;a href=&quot;http://en.blitzortung.org/live_lightning_maps.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Blitzortung project&lt;/a&gt; has near real-time data for most if not all of the world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've also never taken the time to research how lightning detectors exactly work, but it's likely similar... and you can read about the Blitzortung instrument &lt;a href=&quot;http://en.blitzortung.org/cover_your_area.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.windy.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;Windy.com&lt;/a&gt; also appears to now have lightning data over at least the largest part of the globe (perhaps using the Blitzortung source).  And though it's not for your region, GOES new satellites also have a lightning detector on them, which you can view at some data from on any of the GLM links on &lt;a href=&quot;http://cimss.ssec.wisc.edu/goes/goesdata.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this page&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-09-13T15:54:03.797" LastActivityDate="2018-09-13T15:54:03.797" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14664" PostTypeId="2" ParentId="14662" CreationDate="2018-07-22T09:01:54.393" Score="4" Body="&lt;p&gt;Here is another one -&lt;a href=&quot;https://weather.us/lightning/americas&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lightning hits across the world&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can also look at the TRMM lightning sensor data for older periods - &lt;a href=&quot;https://lightning.nsstc.nasa.gov/data/data_trmm_lis.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lightning Sensor &lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is another site that shows world wide lightning strikes  - &lt;a href=&quot;http://wwlln.net/&quot; rel=&quot;nofollow noreferrer&quot;&gt;WWLN&lt;/a&gt; and for those searching for lightning strikes in the Americas here is the link - &lt;a href=&quot;http://wwlln.net/WWLLN_movies/Movie_of_Lightning_in_Americas_BIG.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;Americas Lightning Strikes&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2018-09-12T17:24:36.420" LastActivityDate="2018-09-12T17:24:36.420" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14666" PostTypeId="1" CreationDate="2018-07-22T12:09:30.343" Score="13" ViewCount="1849" Body="&lt;p&gt;Does anybody know where to find statistical (average, standard deviation) data on velocities of ocean currents, such as&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Equatorial countercurrent North of Madagascar&lt;/li&gt;&#xA;&lt;li&gt;Agulhas current&lt;/li&gt;&#xA;&lt;li&gt;East Australia current&lt;/li&gt;&#xA;&lt;li&gt;Gulf stream East of Florida is about $2\,\frac{m}{s}$ (the only figure I have found)&lt;/li&gt;&#xA;&lt;li&gt;South equatorial current North of South America&lt;/li&gt;&#xA;&lt;li&gt;Kuroshio current&lt;/li&gt;&#xA;&lt;li&gt;Antarctic circumpolar current (Strait of Magellan)&lt;/li&gt;&#xA;&lt;li&gt;North equatorial (Philippines)&lt;/li&gt;&#xA;&lt;li&gt;etc.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I have found time series data by NOAA (&lt;a href=&quot;http://coastwatch.pfeg.noaa.gov/erddap/search/index.html?page=1&amp;amp;itemsPerPage=1000&amp;amp;searchFor=ocean%20current&quot; rel=&quot;noreferrer&quot;&gt;link&lt;/a&gt;), but no &quot;postprocessed&quot; values. Is such data available?&lt;/p&gt;&#xA;" OwnerUserId="13435" LastEditorUserId="13435" LastEditDate="2018-07-22T13:09:01.597" LastActivityDate="2023-02-18T13:47:19.577" Title="What is the (average) velocity of ocean currents?" Tags="|ocean|oceanography|ocean-currents|open-data|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14670" PostTypeId="1" AcceptedAnswerId="14684" CreationDate="2018-07-22T22:06:58.207" Score="7" ViewCount="492" Body="&lt;p&gt;Earth's radius is usually given as 6378137 meters (&lt;a href=&quot;https://en.wikipedia.org/wiki/Earth_radius#Global_average_radii&quot; rel=&quot;noreferrer&quot;&gt;equatorial radius&lt;/a&gt;), its flattening is &lt;strong&gt;defined&lt;/strong&gt; as &lt;a href=&quot;https://en.wikipedia.org/wiki/Flattening#Numerical_values_for_planets&quot; rel=&quot;noreferrer&quot;&gt;1/298.257223&lt;/a&gt; (WGS84), and thus its polar radius is &lt;em&gt;calculated&lt;/em&gt; as &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth_radius#Polar_radius&quot; rel=&quot;noreferrer&quot;&gt;6356752 meters&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the average depth of the Earth's oceans is &lt;a href=&quot;https://www.google.com/search?q=average%20depth%20of%20all%20oceans&quot; rel=&quot;noreferrer&quot;&gt;3688 meters&lt;/a&gt; (i.e. 3688 meters below mean sea level), and the average height of all land above the oceans is &lt;a href=&quot;https://www.quora.com/What-is-the-average-elevation-of-Earth-above-the-ocean-including-land-area-below-sea-level-What-is-the-atmospheric-pressure-at-that-elevation&quot; rel=&quot;noreferrer&quot;&gt;840 meters&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming &lt;a href=&quot;https://hypertextbook.com/facts/1997/EricCheng.shtml&quot; rel=&quot;noreferrer&quot;&gt;71% oceans and 29% dry land&lt;/a&gt;, this gives&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$0.71 \times (-3688~{\rm m}) ~+~ 0.29 \times 840~{\rm m} ~=~ -2374.8~{\rm m}$. In other words, 2374.8 meters below (current) mean sea level would be the &quot;billiard-ball&quot; Earth if all the oceans were drained&lt;sup&gt;1&lt;/sup&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, my question is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is the defining elevation of how the Earth's radius is measured?&lt;/strong&gt; Is it the billiard-ball elevation, current mean sea level, or something else?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt; Of course, this ignores the oblateness caused by the flattening and all the undulations described by the &lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Geoid&quot; rel=&quot;noreferrer&quot;&gt;geoid&lt;/a&gt;&lt;/em&gt;.&lt;/p&gt;&#xA;" OwnerUserId="7505" LastActivityDate="2018-07-25T02:12:46.980" Title="What physical measurement / elevation is used to define Earth's radius?" Tags="|geophysics|geography|earth-observation|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14673" PostTypeId="1" AcceptedAnswerId="14685" CreationDate="2018-07-23T17:36:36.343" Score="5" ViewCount="653" Body="&lt;p&gt;I have a question that I thought of when discussing a Worldbuilding scenario &lt;a href=&quot;https://worldbuilding.stackexchange.com/questions/118953/how-would-coral-reefs-thrive-on-this-super-earth-world?noredirect=1#comment366364_118953&quot;&gt;here&lt;/a&gt;. In that question, a super earth with gravity 1.35 times that of earth's is discussed, and is assumed to have shallow oceans. It is the assumed cause of these shallow oceans that got me thinking. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question supposes that the shallow oceans are a result of a crust more uniform than that of earth, i.e without significant variations in depth, and that said uniformity is caused by gravity evening things out somehow. However, the imaginary world is also said to have more volcanic activity than earth, which I interpret to mean at least some tectonic activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My first thought was that there is no reason for gravity, at the scale we are discussing, to influence the uniformity of a planet's crust after its formation, and that plate tectonics would play a much larger role. I suppose the crust would be a bit denser depending on its original composition, and perhaps the &lt;strong&gt;magnitude&lt;/strong&gt; of gravity influences the tectonics themselves more significantly than I realize. (Obviously with no gravity, there are no plate tectonics, and in fact no planet, so that's not what I'm after).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Earth Science Questions:&lt;/strong&gt; What effects, if any, does gravity have on the mountains and depths of earth's crust? Assuming earth-like dynamics at play, would plate tectonics have more of an influence on the formation of a planet's crust's highs and lows than gravity? If not, why?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bonus (World-Building) Question: Is there a way to construct a planet's crust and core such that volcanic activity is possible, yet gravity has the primary influence over &lt;em&gt;crust&lt;/em&gt; uniformity?&lt;/p&gt;&#xA;" OwnerUserId="13441" LastEditorUserId="13441" LastEditDate="2018-07-24T12:49:22.620" LastActivityDate="2018-07-26T13:32:25.683" Title="Plate Tectonics vs Gravity for Creating Highs and Lows" Tags="|plate-tectonics|gravity|planetary-formation|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14677" PostTypeId="2" ParentId="14673" CreationDate="2018-07-24T12:27:59.140" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;What effects, if any, does gravity have on the mountains and depths of&lt;/strong&gt;&#xA;  &lt;strong&gt;earth's crust? Assuming earth-like dynamics at play, would plate&lt;/strong&gt;&#xA;  &lt;strong&gt;tectonics have more of an influence on the formation of a planet's&lt;/strong&gt;&#xA;  &lt;strong&gt;crust's highs and lows than gravity? If not, why?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Consequences at volcanoes and maybe see-mounts altitude would be: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;More gravity, before they collapse-&gt;less altitude.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can measure at Earth the slope where a dune or a volcano collapses, but that's true for 9,8G; physics says the slope would be lower at a planet with 12G.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's the reason -inversed- why &lt;a href=&quot;https://en.wikipedia.org/wiki/Olympus_Mons&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Olympus Mons&lt;/strong&gt;&lt;/a&gt; at Mars reaches 20.000 metters, not seen at Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That doesn't mean the planet would have less altitude at his mountain systems, my guess is orogenies would create systems a bit higger than at Earth are. But individual forms as summits, hillsides,..., resulting from the denundation of the relief created by the orogeny, would be less spectacular. &lt;a href=&quot;https://www.google.es/maps/place/Pico+del+Teide/@28.3054786,-16.7514273,11z/data=!4m5!3m4!1s0xc6a841219a46745:0x8da5b0b3d4897f14!8m2!3d28.2723384!4d-16.642508!5m1!1e4&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Volcanoes as Teide (8.000m from seabed)&lt;/strong&gt;&lt;/a&gt; would have collapsed before reaching that altitude too. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Is there a way to construct a planet's crust and core such&lt;/strong&gt;&#xA;  &lt;strong&gt;that volcanic activity is possible, yet gravity has the primary&lt;/strong&gt;&#xA;  &lt;strong&gt;influence over crust uniformity?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I guess you are talking about a &lt;strong&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Terrestrial_planet&quot; rel=&quot;nofollow noreferrer&quot;&gt;rocky Earth kindly planet&lt;/a&gt;&lt;/strong&gt;. Crust formation and his thick is consequency of the proccess of cooling of the planet. &#xA;It is an insulating layer. If your planet is rocky it will have Crust. His thick is mainly related with the stage of the planet and the starting heat/mass had. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You need to take in consideration at certain depp (certain presure) Crust melts and pass to form a part of Mantle, so the heavy planet may have a non specialy depp Crust. In fact, if the gravity is higger, you would expect to find the discontinuity between Crust and Mantle at lower deep. That doesn't mean at the heavy planet Continental Crust would not occupy a bigger area on the surface of the planet, making the oceans deeper by the way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Crust is not uniform. There is Continental Crust and Oceanic Crust, with chemical and genetical big differences. But I think you are asking about the uniformity of topography, wich is argued previously and bellow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately (I guess for you) if that planet has a bit more gravity the mounts of the videogame, acording to physic laws, should be a bit less spectacular than at Earth are. There would be more landslides at most of geomorphological forms that had a slope. The components of the forms are the same at both planets, but the gravity makes lower the minimal slope when the form collapse.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Volcanic activity and tectonics are related with the total volume of mantle kinding rocks the planet has and the power of the heat the Core shares with the Mantle. Gravity migth be balanced as more 'mantle mass/core heat-mass', more gravity, so your planet could have a bit more of igneous activity, limitated a bit by gravity (volcanic activity, not the internal igneous activity). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my answer is yes, you can design a planet wich has a little more gravity/mass, but very similar to Earth with Core, Mantle and Crust; volcanoes, black smokers at sea bed.... &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Would the planet have shallower oceans?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The deep of the ocean is consequence of how  much developed the Continental Crust is and how much water the planet has. Sea-bed level can be considered the first surface level of the planet, then it will be deeper if the Continental Crust has emerged at long areas of the surface at the continents, and the bulk of water is relatively high. I am not saying gravity would have not any influence (and I am not geophysicist), but my guess is if A planet has 1.3 times B planet's gravity and the main bulk relations of different components are the same then A planet would have 1.3 times the altitude difference between continental_masslands_altitude / average_seabed_altitude, and the deep of his seabed will be at least 1.3 times if there is also 1.3 times the bulk of total water B planet has and they are at the same geological stage. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my answer here is no, unless the heavy planet is at an earlier geological stage with no so much Continental Crust developed or has less total amount of water.&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2018-07-26T13:32:25.683" LastActivityDate="2018-07-26T13:32:25.683" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14681" PostTypeId="2" ParentId="14653" CreationDate="2018-07-24T20:37:20.120" Score="1" Body="&lt;p&gt;I live in Colorado, USA.  All gas stations must have shallow wells drilled around the gasoline tanks to monitor for gasoline tank rupture leaks.  The tanks usually lie above the water table so any gas leaks will travel to the water table and start flowing on top of the groundwater.  One hundred percent contamination happens when a flashlight is shined down the well and a gasoline sheen is seen on the water.  Less contamination is measured by sampling the water. The depth to the water table is also measured.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The point I am getting to, is that all gas stations in Colorado have to be measured every three months and the results sent to the State.  I would suggest that you check for a gas station near where you live and get a recent published water report that you can study.  One of the maps is a water table depth map.  The map will have a contour map with the depth below surface contours and arrows perpendicular to contour lines that show the direction of groundwater flow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would suggest for you to see if your State or Provence has a similar contamination monitoring program. This would give you an idea how the water table behaves in your area. If you go to your nearest gas station and look for circular steel plates about 6 inches in diameter placed flush on the ground around the tanks, gas pumps, and parking lot, then you will know if the station is monitored.  The top of the plate has a filled in triangle with the triangle points touching the circle circumference. Sometimes the plate has a warning that says &quot;DO NOT FILL&quot;.  The the steel plate and map symbol looks like Unicode symbol U1F7D5.&lt;/p&gt;&#xA;" OwnerUserId="13449" LastActivityDate="2018-07-24T20:37:20.120" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14682" PostTypeId="1" CreationDate="2018-07-24T22:43:13.317" Score="3" ViewCount="105" Body="&lt;p&gt;I have a hydraulic fracturing data set with some wells and each well is broken up into stages. My response is total well production and my goal is to be able to predict this total well production. The number of wells is extremely low (&amp;lt;10) for any prediction task though but there are many stages per well and each stage has a rich feature set. To synthetically increase my number of observations I want to try to derive a per stage production that is a little smarter than simply dividing the total well production by number of stages. I am thinking of using Gibbs Sampling to produce observations of stage production using the total well production and stage features as givens and a mild assumption of what the covariance matrix would look like. I am wondering from a hydraulic fracturing perspective if it makes sense to think of the total production being a sum of the individual stages? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For reference I am thinking of multiple stages in terms of this video: &lt;a href=&quot;https://www.youtube.com/watch?v=bABA8WkxG04&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=bABA8WkxG04&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="13450" LastActivityDate="2020-04-22T04:02:30.247" Title="In hydraulic fracturing, can total oil/gas production be broken down by stage?" Tags="|fracking|" AnswerCount="1" CommentCount="2" ClosedDate="2020-04-30T09:38:48.683" ContentLicense="CC BY-SA 4.0" />
  <row Id="14684" PostTypeId="2" ParentId="14670" CreationDate="2018-07-25T02:06:32.270" Score="5" Body="&lt;p&gt;Originally, the concept of a reference ellipsoid was an ellipsoid that best approximated mean sea level. This concept predates satellite-based geodesy by hundreds of years. There are now better ellipsoids in terms of providing a better fit to mean sea level than the WGS84 ellipsoid. Yet the WGS84 ellipsoid is used worldwide (including the ridiculously over-precise flattening value).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The WGS84 reference ellipsoid is now just that, a reference ellipsoid (that is, it's the ellipsoid used as a reference by GPS and related systems). In 1993 the WGS84 governing committee voted, with one exception, to retain the 1984 defining values, despite improvements to those defining values. The one exception: The flattening in the original definition of WGS84 was a calculated value, based on the Earth's second dynamic form factor as determined from satellite orbits ($\bar C_{2,0}$ in WGS84, $J_2$ in GRS80). This calculated value became a defining value in 1993. The reason for keeping those older values was GPS. It's better to have a reference ellipsoid that is constant over time than it is to have an ever improving best fit ellipsoid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Besides, not all of the changes in the best fit ellipsoid represent a reduction in measurement errors. The best fit ellipsoid truly does change over time as the Earth continues to recover from the last glaciation and as the Earth's rotation rate slows down. There are very few applications where a best fit ellipsoid truly is needed while there are many applications where a constant reference ellipsoid is the &quot;best fit&quot;.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2018-07-25T02:12:46.980" LastActivityDate="2018-07-25T02:12:46.980" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14685" PostTypeId="2" ParentId="14673" CreationDate="2018-07-25T04:29:22.990" Score="4" Body="&lt;p&gt;I think this question is less intuitively obvious than it appears. and I like @Universal_learner 's answer.  I thought I'd give a different approach to the question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth is the only object in the solar system with significant amounts of granite and granite is very important to your question because of it's durability and it's buoyancy.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Granite forms under pressure below the Earth's surface in conditions where the magma gradually cools and &lt;a href=&quot;http://nautil.us/blog/how-water-paradoxically-creates-the-land-we-walk-on&quot; rel=&quot;nofollow noreferrer&quot;&gt;it requires the presence of water to form&lt;/a&gt;.    Once formed, Granite is more durable than the denser crustal rock and fairly early in the Earth's history, &lt;a href=&quot;http://earthsky.org/earth/when-earths-continents-rose-above-its-oceans&quot; rel=&quot;nofollow noreferrer&quot;&gt;about 3 billion years ago by this article&lt;/a&gt;, this granite formed into continental crusts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because Granite is lighter than other crustal rock, it floats like a cork in the Earth's crust, about 2/3rds below the surface or ocean, and one third, extending above sea level.   (Continental crust extends beyond the land/ocean boundary).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Higher gravity would likely flatten out the granite to a degree in terms of mountains and valleys but continental crust is in balance with the heavier basalt crust, so I don't see how gravity would effect the continents much.  The rate of erosion from land to sea might increase, but the buoyancy of the granite wouldn't be affected by gravity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The effect on the depth of the oceans is unclear.   Outside of the continental crust that extends below the oceans, and the ridges and trenches, ocean depth is reasonably consistent.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2UPLv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2UPLv.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://geo.libretexts.org/Textmaps/Book%3A_Physical_Geology_(Earle)/18%3A_Geology_of_the_Oceans/18.1%3A_The_Topography_of_the_Sea_Floor&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source of picture&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If on Earth, for example, if you were to drain the oceans, with the weight removed the ocean floor would rise and the continents would sink somewhat, much like they do when a mile of glacial ice forms over and then recedes from the continents and the land shifts up and down, but the altitude variation on Earth, average continental height to ocean floor wouldn't change all that much.  A few hundred feet perhaps out of 2-3 miles in variation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The point is, the ratio of granite continental crust, to surface water would be the primary factor in ocean depth.  Those ratios would be more important than gravity.    Other factors to consider would be weathering and how active the planet's tectonic movement is.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The highest peaks on the Earth are formed by the comparatively rapid movement of two tectonic plates crashing into each other and their height is limited by two factors, gravity and weathering, and I'm not even sure gravity is the bigger of the two factors.    Olympus Mons on Mars is as tall as it is, in part, because Mars has no weathering and in part because Mars has no tectonic movement, so the volcano under Olympus mons keeps adding to the same spot.   That doesn't happen on Earth because our crusts move.    Olympus mons is also very flat because it was formed by lava, not by two crusts pressing against each other, which can form more jagged peaks.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take two granite continental plates slowly pushing into each other at a fixed speed.   How high the mountain range grows would be a factor of their momentum pushing into each other.  Gravity would play a role in how high the mountains could grow before they spread out/landslide across the surface, but the volume of rock being pushed upwards would be a property of the velocity and mass of the two moving plates.   Gravity would add just as much momentum to the collision as it would discourage building the mountains higher.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So ultimately I think the question boils down to these key factors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ratio of continental crust granite to ocean floor.&#xA;How much water is on the planet.   It's not hard to imagine a dry planet with almost no oceans to speak of or a water world with no land at all.&#xA;how active the tectonic movement is&#xA;how much weathering is done by the atmosphere on the planet&#xA;and . . . gravity is a factor too.    But to ask the question considering gravity alone, I think there are too many variables to answer.   From a worldbuilding standpoint, you'd have to consider other things as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, a planet with 1.35 times Earth's gravity, if we assume similar density, equal density to gravity the ratio is 1 to 1, so such a planet would have 1.35^3 or about 2.5 times the mass of the Earth and 1.8 times the surface area.  It would also cool more slowly, having more heat of formation and would, everything else being equal, probably be more volcanic.   How the extra gravity, extra heat and additional matter would affect continent formation and plate tectonics is above my pay grade.   You might need some super-computer modeling to get a more accurate answer.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2018-07-25T04:29:22.990" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="14686" PostTypeId="1" AcceptedAnswerId="14698" CreationDate="2018-07-25T17:19:20.847" Score="3" ViewCount="86" Body="&lt;p&gt;Electricity can come in many forms on Earth but when is amps and/or voltage limited physically on Earth? In other words, what voltage arises naturally on Earth?&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2018-07-26T18:13:11.067" LastActivityDate="2018-07-27T15:21:28.180" Title="What voltage and/or amps cannot be found naturally?" Tags="|geophysics|lightning|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14688" PostTypeId="1" CreationDate="2018-07-26T07:41:10.957" Score="4" ViewCount="75" Body="&lt;p&gt;This is what normal wave motion looks like.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/xhHjU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xhHjU.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do tsunamis that travel at 60mph look any different?&lt;/p&gt;&#xA;" OwnerUserId="6219" LastActivityDate="2018-07-26T07:41:10.957" Title="What does the motion of water in tsunamis look like?" Tags="|water|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14689" PostTypeId="1" CreationDate="2018-07-26T09:03:52.080" Score="4" ViewCount="42" Body="&lt;p&gt;I am a graduate student of Ecology working on a species diversity problem and am not much educated in time series methods. i have searched 3 general time-series books and could not find a clue on how to proceed. I am hoping that seismologists or other earth scientists could help me find a method.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My data, after some processing consists of multiple time series, auto-correlated in space. the time series are quite short compared with typical time-series data, that is 15-30 points and typically without large variation in the series. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to characterize the stability, resistance and resilience of this set of time series (for each one of them).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do you know of any method that is in common use for such problems of stability ?&#xA;I was thinking seismologists may be able to help me, as some of them are probably occupied by the need for fast predictions for earthquakes from multiple sources of data with some spatial auto-correlation.&lt;/p&gt;&#xA;" OwnerUserId="13458" LastEditorUserId="5594" LastEditDate="2018-07-26T16:27:57.197" LastActivityDate="2018-07-26T16:27:57.197" Title="statistical methods for analysis of stability tailored for multiple short time series" Tags="|seismology|statistics|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14690" PostTypeId="1" CreationDate="2018-07-26T15:59:57.257" Score="1" ViewCount="31" Body="&lt;p&gt;My question was inspired by &lt;a href=&quot;https://earthscience.stackexchange.com/questions/3018&quot;&gt;this one&lt;/a&gt; - in particular, the subtopic of pumping water from the ocean to the below-sea-level basins to deal with rising sea levels (spoiler: it's horribly infeasible and impractical).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have also read about topographic prominence, &lt;a href=&quot;http://www.peakbagger.com/help/glossary.aspx#lineparent&quot; rel=&quot;nofollow noreferrer&quot;&gt;line parent(s)&lt;/a&gt;, &lt;a href=&quot;https://bivouac.com//DfnPg.asp?DfnId=1033&quot; rel=&quot;nofollow noreferrer&quot;&gt;key cols&lt;/a&gt;, and the concept of a &quot;&lt;a href=&quot;https://bivouac.com//DfnPg.asp?DfnId=1052&quot; rel=&quot;nofollow noreferrer&quot;&gt;prominence walk&lt;/a&gt;&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then, I was reminded of my experience futzing around with Google Earth's elevation data when trying to understand how &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Assal_(Djibouti)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Assal&lt;/a&gt; is the lowest point in Africa (-155 meters / -510 feet) yet it's unusually close to the ocean (only about 5 km from the Gulf of Aden).&lt;sup&gt;1&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously there's a saddle point above sea level which separates this lake and ocean, plus there are line parents and a prominence walk crossing this saddle point,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;but,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;how about the line of &lt;em&gt;lowest elevation&lt;/em&gt; leading up to this saddle point from each of the Lake and the Gulf, i.e. the &lt;em&gt;converse&lt;/em&gt; of a prominence walk?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;In terms of physical geography and the study of prominences, is there a formal name for this line?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt; Somewhat related:  I've been intrigued for decades about how Reno, Nevada is 4500' elevation but nearby Lake Tahoe is 6220'.&lt;/p&gt;&#xA;" OwnerUserId="7505" LastActivityDate="2018-07-26T15:59:57.257" Title="Is there a formally-defined converse of a Prominence Walk?" Tags="|geophysics|geography|terminology|topography|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14691" PostTypeId="1" CreationDate="2018-07-26T18:18:17.420" Score="1" ViewCount="99" Body="&lt;p&gt;I am not a climate scientist, but I have been reading climate literature lately for my own education. Much of it discusses various effects that could be expected with different levels of warming, usually by 2050 or 2100, e.g. reductions in crop yield, flooding, etc. However, I find it very difficult to intuit what the effects of various scenarios would mean in aggregate. E.g. say we have 4 C warming by 2100. What is the overall level of economic damage globally? Even better, what is a way to get a grasp on the level of damage or suffering that results - is it a societal collapse, or something similar to WWII, or something similar to the Great Depression, or something much less?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any good resources or papers that discuss overall (net amount of damage, net amount of suffering) range of possible effects in an intentionally intuitive manner like this, for different warming scenarios?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that I am not looking for predictions of temperature rise. Ideally, I am looking for predictions of damage that are stated in a way that is easy to get an intuitive global handle on, &lt;i&gt;given&lt;/i&gt; specified temperature rises, by specified years (e.g., presumably 1 C by 2030 would cause more damage than 1 C by 2050 or even 2100).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The closest thing that I have found to this so far are the burning ember diagram in the IPCC reports, and the corresponding referenced papers. This is a step in the right direction as far as what I am looking for, and gives some references that may be helpful (I haven't explored them yet), but still doesn't quite hit the mark for me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyway, this might be a broad and strange question, but an answer or partial answer to it would help me greatly to contextualize the subject as I study it.&lt;/p&gt;&#xA;" OwnerUserId="13460" LastEditorUserId="595" LastEditDate="2018-07-27T13:49:11.990" LastActivityDate="2018-07-27T13:49:11.990" Title="Intuition on overall effects from climate change under different levels of warming" Tags="|climate-change|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14692" PostTypeId="1" CreationDate="2018-07-27T02:54:30.713" Score="7" ViewCount="222" Body="&lt;p&gt;Looking around on the web, I frequently see explanations like &quot;precession is caused by the action of the Sun's gravity on the Earth's equatorial bulge.&quot; That's nice, but I'm interested in a little more detail.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone give a somewhat more detailed explanation of where the Torque comes from? I'm looking for something like &quot;at thus and such a time of year, you have more gravity here and less there; hence the torque acts in thus and such a way&quot;&lt;/p&gt;&#xA;" OwnerUserId="10841" LastEditorUserId="239" LastEditDate="2018-07-27T18:49:46.680" LastActivityDate="2019-05-17T10:04:55.277" Title="Can anyone explain the torque that causes the Earth's axial precession?" Tags="|gravity|axial-obliquity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14693" PostTypeId="1" CreationDate="2018-07-27T06:02:06.423" Score="4" ViewCount="106" Body="&lt;p&gt;Greeting,&#xA;What is the estimated uncertainty value in Temperature, relative humidity, U and V winds of ERA-Interim data?&lt;/p&gt;&#xA;" OwnerUserId="13461" LastEditorUserId="725" LastEditDate="2018-07-28T07:10:32.400" LastActivityDate="2018-07-28T07:10:32.400" Title="Uncertainty In ERA-Interim data" Tags="|meteorology|climate-models|era|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14695" PostTypeId="1" CreationDate="2018-07-27T07:35:49.397" Score="1" ViewCount="35" Body="&lt;p&gt;I am wondering a method to find the steering flow of a tropical cyclone from wind data?&lt;/p&gt;&#xA;" OwnerUserId="3194" LastActivityDate="2018-07-27T07:35:49.397" Title="How to find Steering Flow of a tropical cyclone?" Tags="|tropical-cyclone|cyclone|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14696" PostTypeId="2" ParentId="14693" CreationDate="2018-07-27T09:08:32.767" Score="5" Body="&lt;p&gt;There is no traceable uncertainty associated with each datum in the ERA-Interim reanalysis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;However&lt;/strong&gt;, in ERA-5 there is an &lt;em&gt;ensemble&lt;/em&gt;.  This multiplies the data volume, but it means you can use the spread between the ensemble members to get an estimate.  See &lt;a href=&quot;https://confluence.ecmwf.int//display/CKB/What+is+ERA5&quot; rel=&quot;noreferrer&quot;&gt;ERA-5 page&lt;/a&gt;.  ECMWF want us to use ERA-5 now anyway.&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2018-07-27T09:08:32.767" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14697" PostTypeId="2" ParentId="14691" CreationDate="2018-07-27T11:23:08.670" Score="1" Body="&lt;p&gt;I think you're asking about the sort of outputs that are obtained from climate-change &lt;strong&gt;integrated assessment models&lt;/strong&gt; [IAMs] And now you've got the right search term, your quest will get a lot easier.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You're doing the right thing: start with the IPCC reports. The next step is to follow through on reading their references. And then use google scholar or any proper academic search engine you have access to, to find more recent papers that have also cited those papers that the IPCC cited.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's &lt;a href=&quot;https://www.jbs.cam.ac.uk/fileadmin/user_upload/research/workingpapers/wp1104.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;a pdf on the PAGE09&lt;/a&gt; IAM, an updated version of the PAGE2002 model used for the Stern Review. Chris Hope makes his PAGE model available to other researchers, on request.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's &lt;a href=&quot;https://www.theccc.org.uk/publication/integreted-assessment-modelling/&quot; rel=&quot;nofollow noreferrer&quot;&gt;the UK's Committee on Climate Change report on IAMs&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's the &lt;a href=&quot;http://www.lse.ac.uk/GranthamInstitute/tag/integrated-assessment-model/&quot; rel=&quot;nofollow noreferrer&quot;&gt;London School of Economics' page on IAMs&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And the &lt;a href=&quot;http://www.ucl.ac.uk/energy-models/models/tiam-ucl&quot; rel=&quot;nofollow noreferrer&quot;&gt;TIAM IAM from UCL&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Google Scholar claims to have &lt;a href=&quot;https://scholar.google.co.uk/scholar?as_vis=1&amp;amp;q=%22integrated+assessment+model%22+%22climate+change%22&amp;amp;hl=en&amp;amp;as_sdt=1,5&amp;amp;as_ylo=2014&amp;amp;as_yhi=2019&quot; rel=&quot;nofollow noreferrer&quot;&gt;3000 results&lt;/a&gt; from the last five years on IAMs and climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can probably imagine, there are uncertainties piled on top of uncertainties in this field. The scholarly work on them nevertheless represents the best available set of expert expectations on the sort of damages we are likely to experience with different increases in the concentrations of greenhouse gases.&lt;/p&gt;&#xA;" OwnerUserId="100" LastActivityDate="2018-07-27T11:23:08.670" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14698" PostTypeId="2" ParentId="14686" CreationDate="2018-07-27T15:21:28.180" Score="1" Body="&lt;p&gt;The maximum voltage which can possibly occur depends on the materials involved and the distance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the &lt;a href=&quot;https://en.wikipedia.org/wiki/Breakdown_voltage&quot; rel=&quot;nofollow noreferrer&quot;&gt;breakdown voltage&lt;/a&gt; of an insulator is exceeded, the electric potential difference is large enough to force the material into becoming a conductor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This means that for example when the voltage between two points on the surface of the earth, or two in the sky, or anywhere else connected by air, exceeds about 3kV/ḿm (depending on e.g. humidity) the air between them starts to conduct and the potential will tend to equalize. The same principle applies when the points are separated by materials such as rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It turns out, however, that we are not here interested in the properties of the atmosphere since lightning is &lt;em&gt;insignificant&lt;/em&gt; compared to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Dynamo_theory&quot; rel=&quot;nofollow noreferrer&quot;&gt;geodynamo&lt;/a&gt;. I am not aware of any easily digestible summaries which put the numbers in terms of raw amperage, unfortunately. I did manage to find &lt;a href=&quot;http://shadow.eas.gatech.edu/~cpaty/courses/SpacePhysics2013/SpacePhysics2013/Lectures_files/Lecture13_14_15_2013.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this lecture&lt;/a&gt; which (p. 30) has some estimates of total current in the inner magnetosphere (so in space surrounding the planet, not on it unfortunately) in the multi mega-ampere range.&lt;/p&gt;&#xA;" OwnerUserId="7449" LastActivityDate="2018-07-27T15:21:28.180" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14699" PostTypeId="2" ParentId="14692" CreationDate="2018-07-27T18:44:30.220" Score="3" Body="&lt;p&gt;Any object with a non-spherical moment of inertia tensor that is subject to a non-uniform gravitational field will experience a torque due to the gradient of the gravitational field. This can result in a benefit or a challenge for artificial satellites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth has a non-spherical moment of inertia tensor due to its equatorial bulge, and the Moon's and the Sun's gravitational field are non-uniform (gravitational acceleration more or less follows an inverse square law). This means the Earth is subject to instantaneous gravity gradient torques from the Moon and the Sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These torques would average out to zero if the Earth's equator was aligned with the Earth's orbital plane about the Sun and the Moon's orbital plane about the Earth and if the orbits were circular. Since this isn't the case, residual torques exist after averaging (better: integrating) the instantaneous gravity gradient torques over time. It is these averaged / integrated torques that result in the axial precession.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-07-27T18:44:30.220" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14700" PostTypeId="1" AcceptedAnswerId="14704" CreationDate="2018-07-27T19:00:18.643" Score="4" ViewCount="239" Body="&lt;p&gt;Climate change is now one of the greatest challenges facing humanity, but it seems that we have been here before; if we look at the world's climate over a much longer period than 150 years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;During the Paleocene-Eocene Thermal Maximum which occurred 50m years ago, the poles were ice-free tropical regions, with very high carbon levels, and temperature increases of as much as 5 degrees.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am just wondering if what we are currently seeing was going to happen anyway? Has the discovery of oil, and the resultant human activity just accelerated an already inevitable outcome?&lt;/p&gt;&#xA;" OwnerUserId="13466" LastActivityDate="2022-02-06T05:48:07.570" Title="Was climate change inevitable anyway, or is there more to it?" Tags="|climate-change|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14701" PostTypeId="1" AcceptedAnswerId="14742" CreationDate="2018-07-28T03:02:38.167" Score="4" ViewCount="458" Body="&lt;p&gt;As to P=ρgh, would the height of the atmosphere be affected by an increase in nitrogen and oxygen mass or would the height remain constant?  Thanks!&lt;/p&gt;&#xA;" OwnerUserId="13469" LastActivityDate="2018-08-03T12:45:41.400" Title="If the nitrogen and oxygen in our atmosphere were doubled would the pressure double?" Tags="|atmosphere|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14702" PostTypeId="1" CreationDate="2018-07-28T04:33:38.290" Score="1" ViewCount="23" Body="&lt;p&gt;I understand how anything with an electrical current have a magnetic field including living things. Would a densely populated rain forest or jungle have enough combined magnetic field among the living things in a area have any level of protection from solar radiation compared to seperate?&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2018-07-28T04:47:58.210" LastActivityDate="2018-07-28T04:47:58.210" Title="Do living things have a magnetic field capable of any level of solar protection?" Tags="|geophysics|geochemistry|geomagnetism|biogeochemistry|electromagnetism|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14704" PostTypeId="2" ParentId="14700" CreationDate="2018-07-28T07:16:43.923" Score="5" Body="&lt;p&gt;Earth's climate has changed in the past and will change in the future. It would have changed even if we didn't start spewing enormous amounts of CO&lt;sub&gt;2&lt;/sub&gt; to the atmosphere. The main difference here is the rate at which this is happening. Natural climate change unfolds over thousands or tens of thousands of years (btw - PETM was fairly rapid, but we don't know exactly how rapid). Current climate change happens much faster. You can see temperature records broken &lt;em&gt;every single year&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Our modern civilisation developed in a fairly stable climate. We did not develop in a climate where we had ice-free poles, or higher sea levels. The geopolitical consequences of altering that too fast would be simply too much.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-07-28T07:16:43.923" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14706" PostTypeId="1" CreationDate="2018-07-28T09:47:18.817" Score="49" ViewCount="20595" Body="&lt;p&gt;That honestly doesn't make any sense to me. How could heat pass through a gas one way but not the other? Its not like our upper atmostphere has a bunch of doors that can only open one way. To me, that seems to fly in the face of everything I've been taught about how the physical universe works.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If heat can pass through a substance one way, there's no reason why it can't go through the other way. Except for 'greenhouse gases' apparently. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The closest thing I know of that works this way is one-way mirrors. But that doesn't have the same effect. The reason you can see through one side and not the other is because most light is reflected, but not all. Thus if you're in a dark room, the light coming in from the outside will overwhelm what little light is being reflected from within the room. But if you're on the outside, virtually no light is coming through from the dark side and thus you can only see what is being reflected.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short, it makes no sense to me and flies in the face of everything I've been taught. Now, I'm not a climate change denier. Actually, this is something I just now thought about. I've never really bothered to question it before.&lt;/p&gt;&#xA;" OwnerDisplayName="user13471" LastEditorUserId="-1" LastEditDate="2018-07-31T17:32:34.170" LastActivityDate="2019-10-07T08:45:18.707" Title="How do 'greenhouse gases' let heat in, but not let it out?" Tags="|atmosphere|climate-change|greenhouse-gases|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14707" PostTypeId="2" ParentId="14706" CreationDate="2018-07-28T10:18:15.387" Score="78" Body="&lt;p&gt;In a nutshell:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The radiation that enters is &lt;strong&gt;shortwave radiation&lt;/strong&gt; from the sun.  Solar radiation is dominated by visible (as well as UV and near infrared) radiation with a wavelength mostly between 0.2 µm and 2 µm.  This wavelength is determined by the temperature of the Sun, in the order of 6000 K.  For visible radiation (roughly between 0.4 µm and 0.7 µm), all the gases in the atmosphere are (almost completely) transparent.  Clouds do scatter this radiation so you can't see the Sun directly when it's cloudy, but they still let plenty of light through, so it's still light on a cloudy day (just less bright), although it does feel cooler.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The radiation that leaves is &lt;strong&gt;longwave radiation&lt;/strong&gt;, also known as terrestrial radiation or (incorrectly) as thermal radiation.  For Earth, this is dominated by radiation with a wavelength of mostly between 4 µm and 40 µm.  This wavelength is determined by the temperature of the Earth, at around 290 K.  At these wavelengths, greenhouse gases are mostly opaque.  They absorb the radiation.  The greenhouse gases reradiate the absorbed heat, but in both directions (back to Earth AND up to higher layers in the atmosphere), and at a lower temperature.  The upward longwave radiation gets in turn absorbed by higher-up layers of greenhouse gases, et cetera, such that ultimately the layers of greenhouse gases that do radiate into space tend to be high up in the air (say at 240 K).  Thus, their overall effect is to radiate less heat into space than the Earth surface would in the absence of those gases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most important greenhouse gases are water vapour, carbon dioxide, and methane.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://gisgeography.com/wp-content/uploads/2015/09/Atmospheric-Electromagnetic-Opacity-678x308.png&quot; alt=&quot;Atmospheric opacity&quot;&gt;&lt;br&gt;&#xA;&lt;em&gt;Source: &lt;a href=&quot;https://gisgeography.com/atmospheric-window/&quot; rel=&quot;noreferrer&quot;&gt;gisgeography.com&lt;/a&gt;&lt;/em&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://scienceofdoom.files.wordpress.com/2009/11/blackbody_curve-sun-earth.jpg&quot; alt=&quot;Planck curves&quot;&gt;&lt;br&gt;&#xA;&lt;em&gt;Source: &lt;a href=&quot;https://scienceofdoom.com/2010/06/01/the-sun-and-max-planck-agree/&quot; rel=&quot;noreferrer&quot;&gt;science of doom&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2018-07-29T22:45:17.137" LastActivityDate="2018-07-29T22:45:17.137" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="14708" PostTypeId="1" CreationDate="2018-07-28T11:57:45.937" Score="1" ViewCount="1218" Body="&lt;p&gt;How is the total area of the world's oceans 361 million square kilometres? I can't see how the five individuals ones add to that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I Google &lt;em&gt;how many squared km is this/that ocean&lt;/em&gt;, I get&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RGT5M.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RGT5M.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When add the areas of those five oceans,  106.5+161.8+70.56+14.06+20.33&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ds0PI.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ds0PI.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I get 373.25 million sq km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yet the world ocean, which should be the sum of the 5 oceans, is 361 million sq km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I try this site  &lt;a href=&quot;https://www.infoplease.com/world/world-geography/oceans-and-seas&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.infoplease.com/world/world-geography/oceans-and-seas&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It says Pacific = 155.557,  Atlantic = 76.76,  Indian = 68.556, Southern =2 0.327, Arctic = 14.056&lt;/p&gt;&#xA;&#xA;&lt;p&gt;155.557 + 76.76 + 68.556 + 20.327 + 14.056 = 335 sq km&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, also, not 361 million square km&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any idea why the figures differ and what are the correct figures?&lt;/p&gt;&#xA;" OwnerUserId="5960" LastEditorUserId="2470" LastEditDate="2018-07-29T14:22:03.793" LastActivityDate="2020-05-17T16:07:25.677" Title="How is the total area of the world's oceans 361 million sq km?" Tags="|ocean|oceanography|" AnswerCount="1" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="14710" PostTypeId="1" CreationDate="2018-07-27T18:41:45.640" Score="5" ViewCount="1397" Body="&lt;p&gt;What is the northernmost or southernmost city on Earth which receives no snow? The exact definitions are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;City means any settlement with more than 1000 people permanently residing there&lt;/li&gt;&#xA;&lt;li&gt;&quot;No snow&quot; means the city receives less than 1cm of snow per year on average&lt;/li&gt;&#xA;&lt;li&gt;Northernmost/southernmost refers to the absolute latitude of the city on either the Northern or Southern hemisphere&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://travel.stackexchange.com/questions/4049/snowfall-at-sea-level-closest-to-the-equator&quot;&gt;Related question&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="13477" OwnerDisplayName="JonathanReez" LastEditorUserId="13477" LastEditDate="2018-07-28T18:51:18.377" LastActivityDate="2018-07-29T11:09:11.547" Title="What is the northernmost/southernmost city that receives no snow?" Tags="|extreme-weather|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14711" PostTypeId="2" ParentId="14710" CreationDate="2018-07-27T18:58:30.227" Score="8" Body="&lt;p&gt;On the North American west coast, &lt;a href=&quot;https://www.bestplaces.net/climate/city/oregon/coos_bay&quot; rel=&quot;noreferrer&quot;&gt;Coos Bay, Oregon&lt;/a&gt; is the northernmost place I can find, of any significance, that gets no snow.  Astoria, Oregon gets 2.5 cm of snow per year.  Coos Bay is at 43.4 degrees north latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the east coast, Boston is of similar latitude and gets significant snow, so that coast is out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In western Europe, &lt;a href=&quot;https://www.worldweatheronline.com/a-coruna-weather-averages/galicia/es.aspx&quot; rel=&quot;noreferrer&quot;&gt;A Coruna&lt;/a&gt; seems to be the best candidate, at 43.4 degrees north in Spain.  I had originally thought Guernsey would be a good candidate but it gets a little too much snow, and cities in France seem to get regular snow too, even on the coast.  Venice looks like a tempting alternative, but it seems to get snow consistently, if uncommonly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, so far, 43.4 N seems to be the answer on both the North American and European continents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the southern hemisphere, &lt;a href=&quot;https://www.worldweatheronline.com/comodoro-rivadavia-weather-averages/distrito-federal/ar.aspx&quot; rel=&quot;noreferrer&quot;&gt;Comodoro Ravadavia, Argentina&lt;/a&gt; at 45.8 S gets snow, but &lt;a href=&quot;https://www.worldweatheronline.com/trelew-weather-averages/chubut/ar.aspx&quot; rel=&quot;noreferrer&quot;&gt;Trelew, Argentina&lt;/a&gt; at 43.3 S does not, so the snow band in eastern South America seems to be quite close to the same latitude as we see in western North America.  There are few significant communities on the western Chilean coast, but &lt;a href=&quot;https://www.worldweatheronline.com/trelew-weather-averages/chubut/ar.aspx&quot; rel=&quot;noreferrer&quot;&gt;Puerto Montt, Chile&lt;/a&gt; is snow-free at 41.4 S.  Southern New Zealand is at similar latitudes, but seems prone to heavy snowfalls at times, probably because of its proximity to Antarctic currents and the presence of tall mountains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are quite a few southern islands that are candidates, but most seem to get snow, and none have any significant settlements, short of the Falklands, which definitely do get snow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you get rid of the people requirement, the &lt;a href=&quot;https://en.wikipedia.org/wiki/McMurdo_Dry_Valleys&quot; rel=&quot;noreferrer&quot;&gt;McMurdo Dry Valleys&lt;/a&gt; at 77.3 S are probably the answer.  They are very cold, but so arid that they are largely snow-free all year long.  Snow that does try to fall often sublimates directly into the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="13478" OwnerDisplayName="Jim MacKenzie" LastActivityDate="2018-07-27T21:54:53.197" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="14712" PostTypeId="1" CreationDate="2018-07-28T22:04:46.357" Score="2" ViewCount="29" Body="&lt;p&gt;If I‘d lie on the ground and the ISS became visible, how long could I see it (min/sec), if the circumstances were perfect and I didn't change my position?&lt;/p&gt;&#xA;" OwnerUserId="13480" LastEditorUserId="6298" LastEditDate="2018-07-28T22:09:45.017" LastActivityDate="2018-07-28T22:09:45.017" Title="How long is the ISS visible from Earth?" Tags="|atmosphere|satellites|" AnswerCount="0" CommentCount="3" ClosedDate="2018-07-30T07:27:54.277" ContentLicense="CC BY-SA 4.0" />
  <row Id="14716" PostTypeId="2" ParentId="14701" CreationDate="2018-07-29T04:22:20.557" Score="1" Body="&lt;p&gt;The surface pressure is just the weight of the atmosphere per unit area, so yes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The density decreases with altitude so there is no well defined &quot;top&quot; to it. Assuming constant temperature (&lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_models#Isothermal-barotropic_approximation_and_scale_height&quot; rel=&quot;nofollow noreferrer&quot;&gt;Isothermal-barotropic approximation&lt;/a&gt;) the density decreases exponentially with altitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iiVyj.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iiVyj.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If it were doubled there would the same portion of mass above any given altitude (but more mass above any given altitude).&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2018-08-02T23:53:23.107" LastActivityDate="2018-08-02T23:53:23.107" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14717" PostTypeId="1" CreationDate="2018-07-29T05:58:14.783" Score="3" ViewCount="383" Body="&lt;p&gt;How does this kind of erosion pattern that looks like melting wax form in sandstone? Can you describe the kinds of processes and kinds of rocks that are needed for this? I've seen it in Nevada, but this example is from Jordan.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UZFPu.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UZFPu.jpg&quot; alt=&quot;Image by Ethan Welty&quot;&gt;&lt;/a&gt;&#xA;(Image by Ethan Welty)&lt;/p&gt;&#xA;" OwnerUserId="13485" LastActivityDate="2018-07-29T15:31:47.967" Title="How does this melted-wax erosion pattern form in sandstone?" Tags="|geology|rocks|erosion|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14719" PostTypeId="2" ParentId="8211" CreationDate="2018-07-29T12:06:54.997" Score="0" Body="&lt;p&gt;This is absolutely possible, I was cycling my bike in a completely cloudless sky when I suddenly hit this wall of super humid and hot air. I had never experienced this kind of air before. As I passed into this wall of humid air, it started raining. I guess at 100% humidity, you only need a slight drop in temperature for the water to start falling out of the air.&lt;/p&gt;&#xA;" OwnerUserId="13487" LastActivityDate="2018-07-29T12:06:54.997" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14720" PostTypeId="2" ParentId="14706" CreationDate="2018-07-29T14:41:35.020" Score="25" Body="&lt;p&gt;Gerrit's got the technical answer; I'm going to answer for a layperson.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two ways objects lose heat.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The first, and the way people are most familiar with, is conduction.  Something touches something else, and the hotter material transfers some of its heat to the colder material.  It's why you rapidly lose heat if you wade into cold waters: your body is hot and the water is cold - so the energy from your body seeps into the water you're touching.&lt;/li&gt;&#xA;&lt;li&gt;The second, though, is a bit harder to intuitively grasp: radiation. &#xA;Or if it helps, think of it as light.  Everything emits&#xA;radiation/light - and that light is based on how hot the material is.&#xA;Ever wonder why every material you heat up really how starts to glow&#xA;red first (ovens, stoves, campfire embers, etc)?  That's because when&#xA;its that hot, the energy it's giving off is energetic enough to be&#xA;seen by the human eye as red (the lowest energy color in the&#xA;spectrum.)  Heat it up further, and the color eventually shifts to a&#xA;white.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Make sense so far?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Okay, Earth doesn't lose heat to conduction.  Simply put, it's in a near-vacuum; there's not really anything its touching to transfer its heat to.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Instead, it loses its energy to radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, objects emit radiation based on their temperature.  So the energy coming from the sun?  It's based on the temperature of the surface of the sun: about 6,000 Kelvin (about 10k degrees F).  So the light/energy/radiation coming from it is very high-energy.  That energy strikes earth and heats it up.  But the Earth itself is comparatively cool: an average of 287 Kelvin (56 degrees F.)  So the radiation that earth emits is much lower in energy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And that's the key.  Gasses like Carbon Dioxide don't allow lower-energy radiation to pass as easily has higher-energy radiation.  So while it lets a lot of the sun's energy &lt;em&gt;in&lt;/em&gt;, it doesn't let the radiated energy back &lt;em&gt;out&lt;/em&gt; as easily.&lt;/p&gt;&#xA;" OwnerUserId="13488" LastEditorUserId="13516" LastEditDate="2018-07-30T20:57:06.807" LastActivityDate="2018-07-30T20:57:06.807" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="14721" PostTypeId="2" ParentId="14717" CreationDate="2018-07-29T15:31:47.967" Score="3" Body="&lt;p&gt;Differential erosion, the &quot;wax-drips&quot; have been hardened by chemical deposition, usually by calcium salts, washed down from the soil at the top of the cliff. There are different mineral deposits that can cause this effect including but not limited to calcite, silica, iron, manganese, fine organic matter, alumina, and fine clay, to name a few, anything that can be deposited between the grains of the sand stone will do really. These minerals flow into the sandstone when wet and as the surface dries they act as a cement increasing the durability of the sandstone in the areas that have been wetted by the mineral rich water. The wind then erodes the surface of the rock and because the cemented material is harder it cuts more deeply into the rock between the water pathways.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-07-29T15:31:47.967" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14722" PostTypeId="1" CreationDate="2018-07-29T18:00:26.350" Score="3" ViewCount="346" Body="&lt;p&gt;I grew curious after watching a presentation about the large creatures of prehistoric times. One of the theories cited about why creatures were so big was the increased oxygen in the atmosphere due to there being no ice caps which meant &lt;strong&gt;more available surface area&lt;/strong&gt; for O2 emitting plant life and the &lt;strong&gt;large amount of available landmass&lt;/strong&gt; for creatures to roam freely. This felt like what could be be historical hand-waving so I'm here looking for facts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Modern climatologists scientists argue that rising temperatures and melting ice caps risk submerging land masses from the displacement of frozen ice. This is based upon the fact that the volume of water is greater than that of ice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I did some googling around and saw that most prehistoric representations of Earth and renditions of Pangaea try to squish the shape of our existing continents together but do not address the increase in ocean volume, I assume for illustrative purposes or other simplification. I'm not arguing whether the continents fit together as depicted but rather how much of it existed above the surface of the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that the movements of tectonic plates can also affect what parts of land are underwater by coastal regions shifting lower and those inland shifting higher with the formation of mountains. Water erosion would also play a factor somewhere in all of this in addition to tectonics but only to a point of equilibrium with sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's interesting to consider that we have found and continue to find historical locations which have since become completely submerged. So it may be safe to assume that the oceans have been already been rising naturally for hundreds of years prior to the industrial revolution through other environmental factors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a definitive source of study on the subject of the percentage of landmass above sea level across history with relation to ambient temperature and the presence of ice caps?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm just a hobbyist who enjoys science and history and have no relevant expertise in this area nit this little idea has had be tickled with anticipation all morning. I would love to learn out more. :)&lt;/p&gt;&#xA;" OwnerUserId="13489" LastEditorUserId="11908" LastEditDate="2019-03-17T19:45:08.973" LastActivityDate="2019-03-17T19:45:08.973" Title="What was the percentage of land mass in prehistoric times when temperatures were high enough that we had no ice caps?" Tags="|climate-change|climate|plate-tectonics|earth-history|sea-level|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14723" PostTypeId="2" ParentId="14706" CreationDate="2018-07-30T00:08:49.940" Score="23" Body="&lt;p&gt;To add to Gerrit's excellent answer, I'd like to add a couple more Images. Images always help clarify things for me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Firstly, this one shows the spectrum light coming from the sun in red. The peak is in the visible range*. It also shows the thermal radiation from the earth in blue. This is in the infrared range. Below, it shows how different gases allow transmission of light at different frequencies. There's a lot going on, so for now, just pay attention to the row for Carbon Dioxide - the most well known greenhouse gas. Note how it allows close to 100% transmission in the visible range, but there is a gray patch in the range of frequencies where the earth is radiating. (I've added a circle around this patch.)&#xA;&lt;a href=&quot;https://i.stack.imgur.com/WG3sI.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WG3sI.png&quot; alt=&quot;Atmospheric Transmission&quot;&gt;&lt;/a&gt;&#xA;[&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Atmospheric_Transmission.png]&quot; rel=&quot;noreferrer&quot;&gt;https://commons.wikimedia.org/wiki/File:Atmospheric_Transmission.png]&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly, there's this picture of a metal rod that's been heated to &quot;white hot&quot;. At this temperature it is radiating in the visible range. The hottest part looks yellow-white (~2000K), the medium part looks red (~1000K), and the rest looks black (room temperature, ~300K). So you can see that objects with different temperatures radiate at different wavelengths.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/BhNb1.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BhNb1.jpg&quot; alt=&quot;Red hot metal rod&quot;&gt;&lt;/a&gt;&#xA;[&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Blacksmith_working.jpg]&quot; rel=&quot;noreferrer&quot;&gt;https://commons.wikimedia.org/wiki/File:Blacksmith_working.jpg]&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Actually, the black part of the rod is still radiating, but in the infra-red part of the spectrum, which our eyes can't see. You may be familiar with infra-red cameras being used to measure temperature of people, or as a kind of night-vision. So this last picture from an infra-red camera shows that even &quot;cold&quot; objects like people are emitting radiation. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/114uH.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/114uH.jpg&quot; alt=&quot;Thermal image - hand&quot;&gt;&lt;/a&gt;&#xA;[&lt;a href=&quot;https://en.wikipedia.org/wiki/SGR-A1#/media/File:Thermal_image_-_hand_-_1.jpg]&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/SGR-A1#/media/File:Thermal_image_-&lt;em&gt;hand&lt;/em&gt;-_1.jpg]&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to sum up, the sun is hot (6000K) and emits light, which is mostly in the visible range. Visible light passes through the gases in the atmosphere and heats the earth up to 300K. The earth emits infra-red light which does not pass through Carbon Dioxide. So Carbon Dioxide traps some of the heat which would otherwise have radiated away from Earth. More Carbon Dioxide traps more heat, causing the temperature of the Earth to slowly rise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*saying &quot;the peak is in the visible range&quot; is the easiest way to understand it, but the causality is round the wrong way. Our eyes evolved to have the highest sensitivity in the range where the sun produced the most light.&lt;/p&gt;&#xA;" OwnerUserId="4714" LastActivityDate="2018-07-30T00:08:49.940" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14724" PostTypeId="2" ParentId="14722" CreationDate="2018-07-30T05:23:56.437" Score="1" Body="&lt;p&gt;The real cause rising temperatures is not frozen ocean turning back into water but the volume of the ocean itself expanding (water expands just like everything else when you heat it), and ice on land melting and flowing into the ocean (adding more water). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ice sheets can be tricky to predict but it has been included in &lt;a href=&quot;http://rsta.royalsocietypublishing.org/content/371/2001/20120294&quot; rel=&quot;nofollow noreferrer&quot;&gt;this report&lt;/a&gt; . Although for the most part ic just say whether it exists or not reconstructing total volume of ice is currently not something we can determine accurately.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This chart from that report show how ocean temperature and sea level correlate. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/5jbFs.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5jbFs.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ipcc.ch/pdf/assessment-report/ar5/wg1/WG1AR5_Chapter13_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;This paper&lt;/a&gt; shows how the two factors compare, they are are mostly comparable but ice melt (mostly glacier) is starting to overtake expansion. Great chart on page 1157.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for historical rise, earth used to have two ice sheets, one at each pole (this was responsible for the Asia-North America land bridge), but the northern one has almost completely melted, except for greenland, that is why we had historical sea level rise. There used to be thousands of feet of ice over boston. Land locked ice sheets are very sensitive to temprature, easy to melt, island ones like greenland and antarctica on the other hand create their own sort of insulation by altering circulation. These latter ones are much harder to melt, you need a much greater rise in temprature, which we have created. The last big melt turned england into an island.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OZd25.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OZd25.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2018-07-30T05:23:56.437" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14725" PostTypeId="1" AcceptedAnswerId="14731" CreationDate="2018-07-30T06:27:12.690" Score="2" ViewCount="1239" Body="&lt;p&gt;The original question that was put on hold &quot;If the crust were the thickest layer of Earth, what effect would its thickness have on organisms?&quot;  was actually one of those 'counterfactual question' found on my science book, and it was really just a 'reflect upon' question. And it's actually a hard one for me to answer since it's 'what if?'s. So by revising, it would still confuse some poeple, but I guess it's already specific on its own. But I still find it hard.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Follow up question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And what if it ever was thicker than the mantle or the rest of Earth's layers, can the planet still sustain &lt;em&gt;biological life&lt;/em&gt;?&lt;/p&gt;&#xA;" OwnerUserId="13498" LastEditorUserId="13498" LastEditDate="2018-07-31T13:06:26.137" LastActivityDate="2018-07-31T13:06:26.137" Title="Does crustal thickness have anything to do with how life existed and sustained on Earth?" Tags="|geology|crust|geobiology|" AnswerCount="1" CommentCount="4" FavoriteCount="0" ClosedDate="2018-07-31T10:36:03.757" ContentLicense="CC BY-SA 4.0" />
  <row Id="14728" PostTypeId="1" CreationDate="2018-07-30T15:28:29.613" Score="8" ViewCount="69" Body="&lt;p&gt;We know of course that light from the sun is a fundamental component to making life possible on earth because of the energy it provides. Does the light that is reflected off of the moon make a significant impact on the earth as well? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example - at night, would it be at lot colder on earth without moonlight? And would it basically be pitch-dark on earth without moonlight? Or do stars and other astronomical entities provide a significant amount of light compared to the moon? &lt;/p&gt;&#xA;" OwnerUserId="13512" LastEditorUserId="13512" LastEditDate="2018-07-31T11:48:57.990" LastActivityDate="2018-07-31T11:48:57.990" Title="Is moonlight a significant condition for making life possible on earth?" Tags="|earth-rotation|moon|light|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14730" PostTypeId="1" CreationDate="2018-07-30T22:08:56.133" Score="0" ViewCount="194" Body="&lt;p&gt;I'm trying to extract the APCP variable from a GFS file, with this code:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;wgrib2 gfst.grb2 -match &quot;:(APCP):&quot;  - grib gfst.grb2.small&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;I get a &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;FATAL ERROR: too many grib files .. 1st=gfst.grb2 2nd=-&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;What am I doing wrong?&lt;/p&gt;&#xA;" OwnerUserId="13509" LastEditorUserId="595" LastEditDate="2018-07-31T13:57:15.343" LastActivityDate="2018-07-31T20:44:42.487" Title="Extract a GFS variable" Tags="|meteorology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14731" PostTypeId="2" ParentId="14725" CreationDate="2018-07-30T23:32:41.457" Score="1" Body="&lt;p&gt;If the crust were the thickest layer or Earth, several things would happen:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;It wouldn't be a &quot;crust&quot; any more, by definition. Because this is what a &quot;crust&quot; is: a thin layer on the exterior of something. However, if we assume that the mechanical properties of the crust (being cold and brittle etc) would extend deeper in the Earth, the following applies.&lt;/li&gt;&#xA;&lt;li&gt;No mantle convection, or at least mantle convection weak enough to probably not affect the surface. Therefore, no volcanoes, no mountain building, no subduction, no recycling of volatile elements, no sub-seafloor hydrothermal vents.&lt;/li&gt;&#xA;&lt;li&gt;If it's cold enough, the core probably solidified and there is no magnetic field.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;A good example would be Mars. A planet hypothesised to have tectonic activity in the past, but not any more. The crust of Mars isn't the thickest layer (again - think of definitions), but it is thicker in absolute and relative terms when compared to Earth. I will leave the implications of &quot;Marsifying&quot; Earth on organisms for you to figure out.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-07-30T23:32:41.457" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14732" PostTypeId="1" CreationDate="2018-07-31T02:01:30.383" Score="5" ViewCount="54" Body="&lt;p&gt;The question is about a foreign object, ranging from an asteroid to a spaceship. How large does it have to be in order for its presence to start messing with the weather patterns, causing the like of hurricanes and twisters to appear? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;And as an add on to this question, at what size does it go from causing an atmospheric event to a geological one without touching the ground. &lt;/p&gt;&#xA;" OwnerUserId="13520" LastEditorUserId="2470" LastEditDate="2018-07-31T09:01:42.140" LastActivityDate="2018-07-31T09:01:42.140" Title="How big does something have to be to cause an atmospheric event upon entry to the Earth's atmosphere?" Tags="|meteorology|geology|atmosphere|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14734" PostTypeId="2" ParentId="14728" CreationDate="2018-07-31T09:26:01.353" Score="2" Body="&lt;p&gt;One significant biological event that requires a specific &quot;type&quot; of moonlight is the reproduction of corals in &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Barrier_Reef&quot; rel=&quot;nofollow noreferrer&quot;&gt;Great Barrier Reef&lt;/a&gt;, in Australia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;'&lt;a href=&quot;https://news.nationalgeographic.com/news/2007/10/071019-coral-spawning.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;One week each year in spring, after a full moon&lt;/a&gt;, millions of corals release eggs and sperm in what Bill Leggat, a co-author of the new study, called &quot;a slow symphony.&quot;'&lt;/p&gt;&#xA;&#xA;&lt;p&gt;'&lt;a href=&quot;https://www.sciencedaily.com/releases/2007/10/071019093814.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;An ancient light-sensitive gene&lt;/a&gt; has been isolated that appears to act as a trigger for the annual mass spawning of corals across a third of a million square kilometres of Australia’s Great Barrier Reef, shortly after a full moon.'&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-07-31T09:26:01.353" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14736" PostTypeId="2" ParentId="14730" CreationDate="2018-07-31T12:23:19.140" Score="1" Body="&lt;p&gt;Just to expand upon my comments:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.cpc.ncep.noaa.gov/products/wesley/wgrib2/problems.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;This page from CPC&lt;/a&gt; suggests that the error message is likely due to wgrib2 thinking subsequent arguments are actually additional grib files because they aren't properly given the &lt;strong&gt;-&lt;/strong&gt; prefix.  That lead me to realize that you have a space between your last dash and grib which appears to cause the error:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;wgrib2 gfst.grb2 -match &quot;:(APCP):&quot; - grib gfst.grb2.small&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;should be&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;wgrib2 gfst.grb2 -match &quot;:(APCP):&quot; &lt;strong&gt;-grib&lt;/strong&gt; gfst.grb2.small&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Hopefully that helps if anyone else comes across the issue at a later date!  You might also have forgotten a dash somewhere... or tried using too many arguments in an option?&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-07-31T20:44:42.487" LastActivityDate="2018-07-31T20:44:42.487" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14737" PostTypeId="2" ParentId="12283" CreationDate="2018-07-31T13:00:11.573" Score="7" Body="&lt;p&gt;To summarize &lt;a href=&quot;https://earthscience.stackexchange.com/a/12287/6298&quot;&gt;David's great answer&lt;/a&gt; for folks perhaps looking for an answer more approachable to a wider audience: the answer is a thorough &lt;strong&gt;yes&lt;/strong&gt; to the main question.&lt;br&gt;&#xA;&lt;strong&gt;Hurricanes do have a cooling impact.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hurricanes take warm air near sea level (and evaporated moisture, which is also a form of energy) and release it higher in the atmosphere where it is cooler (the &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_cyclone#/media/File:Hurricane_profile.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;secondary circulation&lt;/a&gt; David mentions)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All weather is really caused by imbalances, and the resulting weather processes naturally work to remove the imbalance... the basic idea behind thermodynamics boils down to the concept that the naturally &quot;desired&quot; state of things is evenness... in other words things seek to smooth out (for example, if you put hot and cold water together, their molecules collide and even out energy until the imbalance between them is gone... leaving only uniform warm water).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is the heat converted into kinetic energy?  &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And yes indeed, a lot of the energy in hurricanes (and for that matter, many storm systems, and even vigorous thunderstorms) is transformed into kinetic energy (which ends up, at least gradually, being dissipated into the surroundings via friction/diffusion/etc).  Though it's worth noting that in hurricanes the wind's kinetic energy (i.e. the strong wind speeds) are actually greatly responsible for acquiring more fuel... by evaporating moisture from the sea's surface (see &lt;a href=&quot;https://www.weatherworksinc.com/how-hurricanes-form-work&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; for a deeper explanation of two central concepts to tropical cyclone energy).  So even though the process gradually dissipates energy, it also winds up continually acquiring more such that those winds can maintain and potentially strengthen tropical cyclones...... up until the fuel source (warm moist water) gets removed.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Could the shape of the hurricanes reflect sunlight?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes, clouds, especially more opaque ones such as found in moist convection (i.e. storms, hurricanes, etc), prevent some of the sunlight and its associated energy from reaching the ground.  This is primarily by reflection (&lt;a href=&quot;https://sciencing.com/colors-reflect-light-8398645.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;particularly by white colored clouds&lt;/a&gt;), but &lt;a href=&quot;http://www.ei.lehigh.edu/learners/cc/planetary4.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;also absorption and scattering&lt;/a&gt;.  And these explain why it's typically at least a bit cooler on a cloudy day.  (Or perhaps all the explanation really needed is to think of how you feel cooler when a cloud suddenly shades you from the sun on a hot afternoon!)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Do they create more lightning in an area that would normally have&#xA;  lower levels of lightning for the same time frame in turn creating&#xA;  more ozone?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As the &lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/G9.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NHC notes&lt;/a&gt;, tropical cyclones are actually not known as heavy lightning producers. This is because the air aloft in hurricanes is warmer than most locations, and lightning generally requires significant ice crystal formation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see in &lt;a href=&quot;https://www.youtube.com/watch?v=clN1M2wBdbg&quot; rel=&quot;nofollow noreferrer&quot;&gt;this fantastic satellite animation of Hurricane Maria&lt;/a&gt; from the new GOES Lightning Mapper from its first year in use in 2017, there still can be a fair bit at times.  There are actually specific situations/locations that encourage increases in lightning activity, and I'd suggest they fit into these categories:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A developing system (less warm air has been released aloft to hinder lightning)&lt;/li&gt;&#xA;&lt;li&gt;Outer edges of tropical cyclones (less warm air has been released aloft in such areas)&lt;/li&gt;&#xA;&lt;li&gt;The eyewall of hurricanes/typhoons (where there is very strong rising motion which can cause increased particle interaction and height)&lt;/li&gt;&#xA;&lt;li&gt;Areas where tropical cyclones interact with land (where land's rougher surface means more friction, which leads to more rapid lifting motion and thus more particle interaction)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;But that said, overall I wouldn't think lightning activity in tropical cyclones is all that different from normal environments in such regions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, ozone released from lightning is put into the troposphere, not the &lt;a href=&quot;https://scied.ucar.edu/atmosphere-layers&quot; rel=&quot;nofollow noreferrer&quot;&gt;stratosphere&lt;/a&gt;.  So it may not work the way you may think of the ozone layer doing.  The ozone layer absorbs most of the higher energy (UV) sunlight.  That &lt;strong&gt;heats&lt;/strong&gt; up the ozone layer... so following that process, ozone from lightning would actually make more sense if it warmed the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, remember that most of the higher energy UV sunlight is already removed from the sunlight (by the ozone layer) before it reaches the troposphere.  So remaining temperature effects should be smaller in the troposphere.  Plus, the amount of ozone created is very very small... the troposphere &lt;a href=&quot;https://www.esrl.noaa.gov/csd/assessments/ozone/2010/twentyquestions/Q1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;only has a very small fraction&lt;/a&gt; of the ozone that the stratosphere does, even with continued lightning.  (In the stratosphere, ozone is made naturally from oxygen directly by the more energetic solar radiation).  And it &lt;a href=&quot;https://www.e-education.psu.edu/meteo300/node/595&quot; rel=&quot;nofollow noreferrer&quot;&gt;appears that more ozone is actually made in the troposphere by pollution than by lightning&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So overall, I'd rate the impact of lightning in tropical cyclones on temperatures to be likely insignificant.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Regardless, overall hurricanes certainly have a &quot;cooling effect&quot; on Earth.  Well, truly they're moving the warmth to cooler locations, so it's really more of a redistribution/mixing effect.&lt;br&gt;&#xA;But in the end, the fact that significant radiation is transferred into kinetic energy and the fact that formed clouds hinder incoming sunlight both certainly work towards cooling the area near hurricanes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, as noted, the wind actually winds up counteracting this by continuing to draw in new warm fuel, such that hurricanes can persist for long periods of time (see &lt;a href=&quot;https://anthonyweather.wordpress.com/2011/09/21/smog-in-los-angeles/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hurricane/Typhoon John&lt;/a&gt;) without weakening due to such cooling factors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Still, there is also one additional factor that ties back in to your kinetic energy subquestion, which at times can more quickly bring harmful impacts to a storm: oceanic overturning.  A strong hurricane can have rapid enough winds to cause significant mixing in the ocean that taps into &lt;a href=&quot;https://en.wikipedia.org/wiki/Thermocline&quot; rel=&quot;nofollow noreferrer&quot;&gt;deeper, colder water&lt;/a&gt; further below the surface.  Check out this &lt;a href=&quot;https://youtu.be/_sgUwbe3ABE?t=113&quot; rel=&quot;nofollow noreferrer&quot;&gt;video from the 2008 hurricane season&lt;/a&gt;, or &lt;a href=&quot;https://svs.gsfc.nasa.gov/1065&quot; rel=&quot;nofollow noreferrer&quot;&gt;this NASA article&lt;/a&gt; involving two hurricanes in 1998.  Now indeed, hurricanes really only start to hinder themselves significantly if they are strong systems and remain nearly stalled for a few days.  And the wake region of cooler sea surface temperatures often doesn't linger all too long.  But that is indeed one additional way yet that hurricanes do &lt;s&gt;cool the Earth&lt;/s&gt; redistribute energy/reduce imbalance.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="2958" LastEditDate="2019-06-03T05:56:17.513" LastActivityDate="2019-06-03T05:56:17.513" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14740" PostTypeId="2" ParentId="14682" CreationDate="2018-07-31T22:57:33.597" Score="1" Body="&lt;p&gt;Don't bother trying to isolate production by stage unless you have a production survey.  Even then it is often irrelevant as the chance of restimulating the specific rock that is lower producing is small.&lt;/p&gt;&#xA;" OwnerUserId="13535" LastActivityDate="2018-07-31T22:57:33.597" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14741" PostTypeId="1" CreationDate="2018-08-01T08:37:03.127" Score="1" ViewCount="79" Body="&lt;p&gt;My country, Spain (40ºN), receives clouds from the Atlantic Ocean during the summer. Our most visited beaches are on the Eastern coast, which sits on the Mediterranean Sea, there is typically more dry weather. The economy there depends on tourists, so imagine my government decides to do &lt;a href=&quot;https://en.wikipedia.org/wiki/Cloud_seeding&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;cloud seeding&lt;/strong&gt;&lt;/a&gt; the three or four times a low pressure area coming from the Atlantic can develop storms that reach the Mediterranean coast each summer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would we expect a much hotter summer at the Mediterranean because the low pressure area lose water?&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2018-08-02T16:49:33.487" LastActivityDate="2018-08-02T16:49:33.487" Title="Can cloud seeding make a much hotter summer, at a middle latitude, at the area that receives less water than expected?" Tags="|meteorology|atmosphere|climate|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="14742" PostTypeId="2" ParentId="14701" CreationDate="2018-08-01T14:47:29.887" Score="1" Body="&lt;p&gt;The starting question is phrased as such ...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to $P=\rho gh$, would the height of the atmosphere be affected by an increase in nitrogen and oxygen mass or would the height remain constant? Thanks!&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Density is mass per volume.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can only add mass to a system in one of two ways. One way is to keep density constant. In this case, volume must increase. Since volume is area times height, either area or height must increase. On the earth, the air on the surface cannot expand itself laterally. Area is constant. Therefore, we learn&lt;/p&gt;&#xA;&#xA;&lt;p&gt;—&gt; ANSWER 1: As mass is added to air on the earth under the condition of constant density, the height of the air above the earth will increase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another way to add mass is to allow density to change. The intuitive first response is that, when we add mass, we expect density will increase. At the limit, this is the same as keeping volume constant. For this case, we learn&lt;/p&gt;&#xA;&#xA;&lt;p&gt;—&gt; ANSWER 2: As mass is added to the air on the earth under the condition where density increases, the limiting case is one where the height of the air above the earth will not change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, we could argue that we want to allow volume to expand somewhat as mass is added. The result is an answer between the two above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that air is compressible. Its density will change as a function of pressure and temperature. By the ideal gas law, $\rho = M n / V = M p / R T$ where molar mass, moles, volume, pressure, gas law constant, and temperature are used. The overall effect is that density is not a constant for the system of air above the earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any other answer requires that we have clearer specifications of the system. We correspondingly learn, either the equation quoted is of no consequence to the question or the question is not phrased properly in respect to the equation quoted.&lt;/p&gt;&#xA;" OwnerUserId="13534" LastEditorUserId="13534" LastEditDate="2018-08-02T18:53:02.130" LastActivityDate="2018-08-02T18:53:02.130" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14743" PostTypeId="1" AcceptedAnswerId="14755" CreationDate="2018-08-01T15:47:36.477" Score="1" ViewCount="1431" Body="&lt;p&gt;From my research, some volcanic eruptions can produce enough force to turn a 10-tonne rock into a projectile.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could a supervolcano produce enough force to turn a 35,000 tonne rock into a projectile?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could a supervolcano produce enough force to project a 35,000 tonne rock ~2000km away from the source?&lt;/p&gt;&#xA;" OwnerUserId="13276" LastActivityDate="2019-01-14T16:45:45.500" Title="Volcanic eruption force" Tags="|geophysics|volcanology|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14746" PostTypeId="1" AcceptedAnswerId="14747" CreationDate="2018-08-01T20:32:33.233" Score="1" ViewCount="664" Body="&lt;p&gt;I'm a volunteer for 350, a grassroots organization that is fighting against climate change through education and advocacy. We're all volunteers, not climate scientists, and I'm looking for some knowledge about the equations that climate scientists use to predict global temperatures with respect to time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm aware that most climate models rely on the Navier-Stokes partial differential equations (&lt;a href=&quot;https://ima.org.uk/688/predicting-climate-change/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate Models&lt;/a&gt;), but I don't have enough knowledge, nor have I easily found a source online that discusses the resulting approximate solution equations that scientists use to make their predictions. I've only seen graphs. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Do you have any references that contain equations from which one can easily make a prediction of temperature for a given year? (I realize that the derivation of such an equation will be complicated, but I'm not concerned about that.)&lt;/strong&gt; &lt;/p&gt;&#xA;" OwnerUserId="13540" LastActivityDate="2018-08-01T21:17:13.177" Title="Equations for Global Temperature Models" Tags="|climate-change|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14747" PostTypeId="2" ParentId="14746" CreationDate="2018-08-01T21:17:13.177" Score="4" Body="&lt;p&gt;The &lt;a href=&quot;http://mathworld.wolfram.com/Navier-StokesEquations.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Navier-Stokes equations&lt;/a&gt; are just a couple of the equations used in Climate Models, but they are the most complex set of equations used, and describes the movement of wind. Unfortunately there is no known solution to them yet (&lt;a href=&quot;http://www.claymath.org/millennium-problems/navier%E2%80%93stokes-equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;though if you come up with one, there is a million dollar prize waiting for you&lt;/a&gt;). Another equation used by complex models is the conservation of energy (which in layman's terms can be describes as):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How the temperature changes at a certain point&lt;/strong&gt; = &lt;strong&gt;How fast wind is blowing warm/cold air to the point&lt;/strong&gt; + &lt;strong&gt;How fast the air is cooling by expanding or warming by compression&lt;/strong&gt; + &lt;strong&gt;Net heating/cooling (from the sun, clouds, greenhouse gases, etc.)&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With more math, sophisticated techniques, and use of previous research, a prediction is made by the climate model, for just a couple seconds or minutes into the future. Then that prediction is used for the next start of the climate model. This is also how weather models work, but climate models repeat this process for years, decades, and centuries. Climate models also consider different factors from weather models, like what is in the air. Different models have different preferences and consider different scenarios.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can find some of the results in the &lt;a href=&quot;http://www.ipcc.ch/pdf/assessment-report/ar5/syr/SYR_AR5_FINAL_full_wcover.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC report&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But if you want a simple mathematical model, the simplest out there is the &lt;a href=&quot;https://math.nyu.edu/faculty/kleeman/zero_dim_ebm.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;zero-dimensional energy balance model&lt;/a&gt;. It won't really predict the temperature to any sort of accurate degree, but it is a useful balance to know.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2018-08-01T21:17:13.177" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14748" PostTypeId="2" ParentId="14306" CreationDate="2018-08-01T21:24:32.673" Score="0" Body="&lt;ol&gt;&#xA;&lt;li&gt;Divide by the depth of the soil&lt;/li&gt;&#xA;&lt;li&gt;Divide by the density of water, or something resembling density.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="704" LastActivityDate="2018-08-01T21:24:32.673" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14749" PostTypeId="1" AcceptedAnswerId="14751" CreationDate="2018-08-01T21:33:37.910" Score="15" ViewCount="813" Body="&lt;p&gt;On my random explorations of google maps, I came across this interesting terrain:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aP5x8.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aP5x8.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(link to map &lt;a href=&quot;https://goo.gl/maps/YXUciTrHN692&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apparently, this is part of the so-called Hamad Plateau, in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Syrian_Desert&quot; rel=&quot;noreferrer&quot;&gt;Syrian desert&lt;/a&gt;. If so, the rock would be limestone, which I read is not directly related to volcanoes. But it just kind of look like it from above. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyone has some information on what this geological area is? I can find little about it, eve it even is the Hamad Plateau. I must say that I have zero knowledge of geology. Zooming in you see a lot of rock and desert, and not so much height variation, so maybe it's not a volcano. Still, it's interesting by the colour and shape. Any help is more than welcome!&lt;/p&gt;&#xA;" OwnerUserId="13541" LastEditorUserId="6467" LastEditDate="2019-08-27T23:53:33.477" LastActivityDate="2019-08-27T23:53:33.477" Title="Is this a former volcano in the Hamad Plateau, in the Syrian desert?" Tags="|volcanology|desert|ground-truth|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14750" PostTypeId="2" ParentId="14743" CreationDate="2018-08-01T21:41:32.800" Score="0" Body="&lt;p&gt;Yes and &lt;strong&gt;Yes just not as a solid&lt;/strong&gt;, the largest yellowstone eruption threw 240 cubic miles of ash (~2,180,000,000,000 metric tons) in to the sky. the largest volcanic bomb/block I know of is 120 metric tons. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2018-08-01T21:41:32.800" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14751" PostTypeId="2" ParentId="14749" CreationDate="2018-08-02T02:21:44.373" Score="11" Body="&lt;p&gt;My Rand-McNally Atlas shows the signature for lava fields in that area. The elevations in Google Maps indicate concentric contour lines with only small differences in elevation, rising from 600m at the outer perimeter to 700m in its center. This a shallow cone-shaped formation. Best I can tell from &lt;a href=&quot;https://en.wikipedia.org/wiki/Al-Safa_(Syria)&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt; (compare the picture there), this feature is:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;As-Safa (Arabic: الصفا‎, Aṣ-Ṣafā), also known as Tulul al-Safa (تلول&#xA;  الصفا, Tulūl Eṣ-Ṣafā), Arabic for Al-Safa hills, is a hilly region&#xA;  which lies in southern Syria, north-east of Jabal Al-Arab volcanic&#xA;  plateau.  It consists of a basaltic lava field of volcanic origin,&#xA;  covering an area of 220 square kilometres, and contains at least 38&#xA;  cinder cones.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthobservatory.nasa.gov/images/45840/es-safa-volcanic-field-syria&quot; rel=&quot;noreferrer&quot;&gt;NASA Earth Observatory&lt;/a&gt; provides a satellite view as well and gives a few more details regarding the very noticeable dark area:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Es Safa contains numerous vents that have been active during the&#xA;  Holocene Epoch (beginning approximately 12,000 years ago). The most&#xA;  recent recorded activity was a boiling lava lake observed in the area&#xA;  around 1850. The dark lava flow field (center) likely represents the&#xA;  latest activity of the volcanic field, and is emplaced over older,&#xA;  lighter colored flows.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="5255" LastEditorUserId="5255" LastEditDate="2018-08-02T02:38:43.890" LastActivityDate="2018-08-02T02:38:43.890" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14752" PostTypeId="1" AcceptedAnswerId="14753" CreationDate="2018-08-02T07:42:35.500" Score="5" ViewCount="1415" Body="&lt;p&gt;I need help with latent and sensible heat. P.S: I have been through all Wikipedia and other pages that say phase change and temperature change. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My Question is: if there is convection, it will take the heat away from surface, what is the chances that the heat taken is latent or sensible?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Evaporation is also convection and heat transfer is also convection, so where does sensible and latent heat stands in this story. &lt;/p&gt;&#xA;" OwnerUserId="8158" LastEditorUserId="2470" LastEditDate="2018-08-02T14:10:30.887" LastActivityDate="2019-11-27T14:00:54.313" Title="Sensible and Latent Heat. how to separate them" Tags="|climate|thermodynamics|energy-balance|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14753" PostTypeId="2" ParentId="14752" CreationDate="2018-08-02T12:48:08.633" Score="5" Body="&lt;p&gt;First some definitions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Latent heat&lt;/strong&gt; is the heat that leaves or enters a system during a process where the temperature of the system stays constant. Phase changes are prime examples where latent heat leaves (exothermic) or enters (endothermic) a system. Ice melts (endothermic) and water freezes (exothermic) at constant temperature. &lt;strong&gt;Sensible heat&lt;/strong&gt; is the heat that enters or exits a system when the temperature of the system changes. Heating or cooling water are cases that involve sensible heat. All heat flow between two systems requires a temperature difference between the systems. &lt;strong&gt;Convection&lt;/strong&gt; is heat flow between two systems by movement of mass. The two other heat flows are &lt;strong&gt;conduction&lt;/strong&gt; and &lt;strong&gt;radiation&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now to the questions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During a phase change, the temperature of the system stays constant. The heat gained or lost is called latent heat. To vaporize a liquid, we must supply heat. Hence vaporization is endothermic (heat enters the system). To get the heat into the system, we must set the surroundings at a hotter temperature. Otherwise the heat will not flow. The process by which the heat flows can be any one of the three modes. We can set a pot of water in a pan on an electric heater and realize conduction from the burner to the pan to the water. We can set use a hair dryer to blow hot air over the pot and realize (forced) convection from the air to the pan. Finally, we can set the pot a small distance above the glowing electric burner and realize radiation from the electric burner to the pot.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By contrast, consider the case of a day where the outside temperature is below freezing and the air is still. A duck pond in the yard is not frozen over. Clearly, it’s water temperature is above freezing. Should we jump in the duck pond to warm up? Of course not! The natural convection coefficient of stagnate water is higher than the natural convection coefficient of stagnate air (and the difference only becomes greater in flowing water versus flowing air). The water pulls heat from us by convection faster than the air does at the same temperature, and our body temperature will drop faster than when we would stay standing in the still air. Also, while the conduction coefficient of water is larger than that for air, the main heat transfer in a fluid is convection, even in stagnate cases. The heat that flows out of our body as our body temperature drops is sensible heat.&lt;/p&gt;&#xA;" OwnerUserId="13534" LastEditorUserId="13534" LastEditDate="2019-11-27T14:00:54.313" LastActivityDate="2019-11-27T14:00:54.313" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14754" PostTypeId="1" CreationDate="2018-08-02T15:43:57.053" Score="4" ViewCount="24" Body="&lt;p&gt;I am studying a simple dynamical system that represents a plant and water system, similar to &lt;a href=&quot;http://science.sciencemag.org/content/284/5421/1826&quot; rel=&quot;nofollow noreferrer&quot;&gt;Klausmeier&lt;/a&gt;. In Klausmeier model the mean annual precipitation and the soil evaporation are introduced as separate parameters. However, there should be some statistical dependence of the soil evaporation be the mean annual precipitation. Anyone knows about a heuristic relation between the two?  &lt;/p&gt;&#xA;" OwnerUserId="5747" LastActivityDate="2018-08-02T15:43:57.053" Title="Statistical dependence of mean annual soil evaporation and mean annual precipitation globally" Tags="|models|precipitation|numerical-modelling|evaporation|soil-moisture|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14755" PostTypeId="2" ParentId="14743" CreationDate="2018-08-02T15:44:57.777" Score="1" Body="&lt;p&gt;For visualization purposes, if the $35,000$ tonne rock was composed of something similar to basalt, with a density of $3 g/cm^3$ (also $3 t/m^3$), it would be a sphere with a diameter of $28.1$ m, or a cube with sides of $22.7$ m. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using a &lt;a href=&quot;http://www.convertalot.com/ballistic_trajectory_calculator.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ballistic trajectory calculator&lt;/a&gt;, to move anything $2000$ km down range, the object needs an initial velocity of $4430$ m/s ($15,948$ km/h, or Mach $12.9$ - hyper sonic speed), assuming a projection angle of $45$ degrees to the horizon. The rock would reach height of $500$ km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The kinetic energy of such an object would be $3.434(10)^{14}$ J, using the equation $E_k = 0.5mv^2$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When &lt;a href=&quot;https://science.howstuffworks.com/environmental/energy/energy-hurricane-volcano-earthquake2.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mount St. Helens erupted&lt;/a&gt; in 1980, it released $24$ megatons of thermal energy. Using a &lt;a href=&quot;https://www.unitconverters.net/energy/megaton-to-joule.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;converter&lt;/a&gt;, this is equivalent to $1.004(10)^{17}$ J. This is 292 times the energy required to move a $35,000$ tonne rock $2000$ km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, the energy released by Mount St. Helens was the overall energy released, not the energy given to one lump of rock and Mount St. Helens was not a supervolcano. So, could a supervolcano shoot a $35,000$ tonne rock $2000$ km away? Potentially, but unlikely. Energy always takes the path of least resistance so instead of moving a $35,000$ tonne rock $2000$ km away it will more likely move significantly more material that is in the form of dust or ash.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-08-02T15:44:57.777" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14756" PostTypeId="2" ParentId="14752" CreationDate="2018-08-02T18:40:06.563" Score="2" Body="&lt;p&gt;Sometimes in meteorology, at least here in the US, we actually call thunderstorms &lt;a href=&quot;https://www.atmos.illinois.edu/cms/One.aspx?portalId=127458&amp;amp;pageId=209972&quot; rel=&quot;nofollow noreferrer&quot;&gt;convection&lt;/a&gt;, which can confuse the terminology a bit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Moist_convection&quot; rel=&quot;nofollow noreferrer&quot;&gt;moist convection&lt;/a&gt; (e.g., storms) and &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Dry_convection&quot; rel=&quot;nofollow noreferrer&quot;&gt;dry convection&lt;/a&gt; (e.g., thermals). Sensible heat (and/or dynamical processes like &lt;a href=&quot;http://okfirst.mesonet.org/train/meteorology/Fronts.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;fronts&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Orographic_lift&quot; rel=&quot;nofollow noreferrer&quot;&gt;orographic lift&lt;/a&gt;, or &lt;a href=&quot;http://www.atmos.millersville.edu/~lead/OMEGA/QG_Omega_Home.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;positive vorticity advection increasing with height&lt;/a&gt;) initiate the rising motion to start such convection.  All air has moisture, it's just that in moist convection, latent heat &lt;strong&gt;subsequently&lt;/strong&gt; becomes important as a byproduct of the initial rising air, and the result becomes is something wet!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the atmosphere is sufficiently moist, and the lift is enough to reach the &lt;a href=&quot;http://www.theweatherprediction.com/habyhints/299/&quot; rel=&quot;nofollow noreferrer&quot;&gt;LCL&lt;/a&gt;... then within the rising air the water vapor will begin to &lt;a href=&quot;http://www.physicalgeography.net/fundamentals/8d.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;condensate/deposit&lt;/a&gt;... which thereby releases its latent heat into the air... and this additional energy help the air to rise further (since it will aid it in being warmer [and thus less dense] than surrounding air).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So convection itself is a sensible process, basically warmer air moving up into cooler air.&lt;br&gt;&#xA;But latent heat release from condensing rain drops (or other precipitation forming) will add &lt;strong&gt;extra&lt;/strong&gt; energy to help the air convect even more, and is vital in the formation of the strong updrafts in thunderstorms.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The initial energy that convection is taking upwards... will generally be from sensible heat.  This is because the only form of latent heat transfer which would add energy to the atmosphere... would be &lt;a href=&quot;https://climate.ncsu.edu/edu/Heat&quot; rel=&quot;nofollow noreferrer&quot;&gt;condensation/freezing/deposition&lt;/a&gt;.  But those basically only happen in air that is cooling down... since temperature drops are the most effective way to bring air nearer to saturation quickly.&lt;br&gt;&#xA;And if near-surface air undergoes cooling, it will generally be unable to rise.&lt;br&gt;&#xA;There's really one time there's condensation/deposition from the near-ground air layer: &lt;a href=&quot;http://www.theweatherprediction.com/basic_weather_questions/dew_frost.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;towards dawn&lt;/a&gt;.  Coming as a result of the surface air layer losing energy via conduction to the &lt;a href=&quot;https://www.reddit.com/r/askscience/comments/6pcxad/why_does_the_ground_cool_faster_than_the_air_at/&quot; rel=&quot;nofollow noreferrer&quot;&gt;colder ground&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;(Note that in meteorology, though all motion of air of different temperatures can be legitimately termed convection... we also typically use the term primarily in regards to vertical motion.  Horizontal motion of air masses is called &lt;a href=&quot;http://GeneralCondensationConvectionTemperaturePressure&quot; rel=&quot;nofollow noreferrer&quot;&gt;advection&lt;/a&gt;.  But advection can certainly move energy just the same, it's just often driven by somewhat different atmospheric processes)&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2018-08-02T18:40:06.563" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14760" PostTypeId="1" AcceptedAnswerId="14763" CreationDate="2018-08-02T21:22:38.720" Score="4" ViewCount="59" Body="&lt;p&gt;How can I split all the &lt;strong&gt;climate modes of variability&lt;/strong&gt; that you can find &lt;a href=&quot;https://www.esrl.noaa.gov/psd/data/climateindices/list/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, into &lt;em&gt;positive&lt;/em&gt;, &lt;em&gt;negative&lt;/em&gt; and &lt;em&gt;neutral&lt;/em&gt; phases?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that depending on the climate mode there exist different methods of achieving this. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do you know any general literature that can help me?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="11493" LastEditorUserId="11493" LastEditDate="2018-08-03T13:05:10.323" LastActivityDate="2018-08-03T14:19:23.407" Title="How to split climate modes of variability into positive, negative and neutral phases?" Tags="|climate|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14761" PostTypeId="1" CreationDate="2018-08-03T12:38:39.370" Score="0" ViewCount="867" Body="&lt;p&gt;![crystal rock yelowish to red yellow to orange has 3 layers of crystal&#xA;)&lt;img src=&quot;https://i.stack.imgur.com/9oTcU.jpg&quot; alt=&quot; both chunks of rock came from the same peace broke of a chunk of the smaller one is one that we started to polish  has sharp crystal edges and it goes right thru the rock in huge vains  &quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Mkgsl.jpg&quot; alt=&quot;found by the river  looks like foam  yellow to dark red orange  3 layers of crystal then rock &quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="13545" LastActivityDate="2018-08-06T11:49:23.473" Title="I found this huge rock crystal by the river have no idea what it is?" Tags="|geology|" AnswerCount="1" CommentCount="3" ClosedDate="2019-08-30T17:55:25.530" ContentLicense="CC BY-SA 4.0" />
  <row Id="14763" PostTypeId="2" ParentId="14760" CreationDate="2018-08-03T14:19:23.407" Score="1" Body="&lt;p&gt;I think thats a lot of information on the link you pasted. and the indexes shown there are mostly in time (time-series). &#xA;Please note two important steps. &#xA;FIRST: the index you want to use is already produced in scientific way and published so how is the index produce please read the relevant paper for that which can help. Apart from that these indexes are mostly (Not all of them) are usually developed to capture/shows standardized/normalized/Anomalous  behaviors of the system. So these indexes are representation of the systems with mean of zero and standard deviation of usually one in case of standardized index, and so does varies for each one of them. The anomaly is different story and i won't go there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;SECOND: Now the deviation of the index from mean (which is zero) shows the deviation from mean conditions (that means from neutral conditions). So positive and negative will show the modes of system based on intended interpretation. like for strength positive deviation will be termed as strong and vice versa. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally you can select the positive and negative years as modes of climate with positive and negative deviation from mean. Further to dig deep you can look for mechanism and principals that led to these deviations. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to use your data and look for modes of climate, then i will suggest PCA, SVD and EOF analysis which may not be applicable in this case.&#xA;I hope that will help  &lt;/p&gt;&#xA;" OwnerUserId="8158" LastActivityDate="2018-08-03T14:19:23.407" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14764" PostTypeId="1" AcceptedAnswerId="14766" CreationDate="2018-08-03T18:39:24.403" Score="6" ViewCount="4068" Body="&lt;p&gt;Can lava that has cooled to a hardened state be returned to a molten state by, say, a new river of molten lava flowing over it - like re-smelting iron? If you threw a lava rock into the mouth of a volcano, would it remain in its solid state or would it melt and become part of the cauldron of magma?&lt;/p&gt;&#xA;" OwnerUserId="13547" LastEditorUserId="13547" LastEditDate="2018-08-04T00:39:03.473" LastActivityDate="2018-08-04T02:22:03.163" Title="Can cooled/hardened lava rock return to a molten state?" Tags="|volcanology|petrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14766" PostTypeId="2" ParentId="14764" CreationDate="2018-08-04T02:22:03.163" Score="4" Body="&lt;p&gt;Yes, at least partially.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is important to remember that a &quot;rock&quot; usually does not have a single melting point. It melts over an interval. Igneous (magmatic) rocks are made of combination of minerals (for example, quartz, olivine, pyroxene, feldspar) that each will melt at a different point. When a rock is heated up, the minerals with the lower melting point melt first, followed by the higher melting point minerals with progressive heating.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some rocks are composed mostly of easier-to-melt material (for example the stuff that came out of Mt. St Helens, mostly granitic composition) and others are made of harder-to-melt material (for example Hawaiian basalts). Taking a a granite and throwing it into a basalt will melt most of it for sure, if not all. Not the opposite though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even if you do not completely melt the rock, you will disintegrate it enough that the remaining harder-to-melt minerals will just drift away and mix with the lava, making it impossible to distinguish the original rock any more.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Likewise, when hot lava flows on easy-to-melt material (for example clay-rich soil), some of it will melt or vitrify (turn to glass).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will finish by emphasising that all lavas, every single one of them, were originally solid rocks that melted at depth by some kind of process. So yes, it is possible to melt rocks.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-08-04T02:22:03.163" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14775" PostTypeId="1" CreationDate="2018-08-05T11:46:31.160" Score="1" ViewCount="38" Body="&lt;p&gt;I think of the non-ionizing range, e.g. Terahertz or Radio. Limestone clearly is transparent to x-ray or gamma but thats not what i am asking for. Natural to low ranges of porosity/water content assumed.&lt;/p&gt;&#xA;" OwnerUserId="10751" LastActivityDate="2018-08-05T11:46:31.160" Title="Which wavelengths is limestone most transparent to?" Tags="|geophysics|soil|limestone|radar|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14777" PostTypeId="1" CreationDate="2018-08-05T13:05:18.207" Score="1" ViewCount="88" Body="&lt;p&gt;I recently &lt;a href=&quot;https://www.smbc-comics.com/comic/gaia&quot; rel=&quot;nofollow noreferrer&quot;&gt;stumbled&lt;/a&gt; upon the &lt;a href=&quot;https://en.wikipedia.org/wiki/Gaia_hypothesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gaia hypothesis&lt;/a&gt;, which briefly states that the Earth itself is a living organism.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am wondering: Would this hypothesis have any practical use? Does it make any predictions? Or alternatively: How could it be falsified?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While the Wikipedia article lists a few detailed examples for homeostatic mechanisms, these do not seem to have been predicted, but interpreted a posteriori (I may be wrong about this though). Criticisms of the hypothesis being a metaphor are referenced, but the word &lt;em&gt;falsify&lt;/em&gt; does not appear in the article.&lt;/p&gt;&#xA;" OwnerUserId="5487" LastActivityDate="2018-08-05T13:05:18.207" Title="Would the Gaia hypothesis have any practical use?" Tags="|planetary-science|earth-system|ecology|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14778" PostTypeId="1" CreationDate="2018-08-05T14:35:27.697" Score="2" ViewCount="630" Body="&lt;p&gt;I found the rock on the beach.  It has a redish hue and floats on water.  It feels as though it is hollow because it is light for its size.  Does anyone have an idea what this is?&lt;a href=&quot;https://i.stack.imgur.com/PixBf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PixBf.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13554" LastActivityDate="2018-08-06T10:56:50.283" Title="Floating rock found in southern florida" Tags="|ocean|" AnswerCount="1" CommentCount="2" ClosedDate="2019-08-30T17:55:03.560" ContentLicense="CC BY-SA 4.0" />
  <row Id="14781" PostTypeId="2" ParentId="14778" CreationDate="2018-08-05T16:28:05.850" Score="10" Body="&lt;p&gt;This isn't a rock at all, but a seed of &lt;em&gt;&lt;a href=&quot;https://en.m.wikipedia.org/wiki/Entada_gigas&quot; rel=&quot;nofollow noreferrer&quot;&gt;Entada Gigas&lt;/a&gt;&lt;/em&gt;, sometimes called the &lt;strong&gt;sea heart&lt;/strong&gt; or &lt;strong&gt;sea bean&lt;/strong&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/b/b7/Entada_gigas1.jpg&quot; alt=&quot;Entada Gigas seeds&quot;&gt;&#xA;(&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Entada_gigas1.jpg#mw-jump-to-license&quot; rel=&quot;nofollow noreferrer&quot;&gt;CC-BY-SA-3.0&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Entada Gigas&lt;/em&gt; is called the &quot;sea bean&quot; for good reason: it's a member of the bean family &lt;em&gt;&lt;a href=&quot;https://en.m.wikipedia.org/wiki/Fabaceae&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fabaceae&lt;/a&gt;&lt;/em&gt;. In fact, this species has the family's largest seed,  a flattened heart shape 6 cm in diameter and 2 cm thick.  These hollow seeds are washed into the ocean and drift on currents for up to 2 years, on the chance that one will wash up somewhere to germinate.  It seems that sea beans have evolved to propagate in this way, similar to &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Coconut&quot; rel=&quot;nofollow noreferrer&quot;&gt;coconut&lt;/a&gt;s.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2018-08-06T10:56:50.283" LastActivityDate="2018-08-06T10:56:50.283" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14782" PostTypeId="1" CreationDate="2018-08-05T17:59:59.890" Score="0" ViewCount="1072" Body="&lt;p&gt;It's greenish yellow with white. Got it in a mixed stone package from Amazon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No luster, I'd say a 7 in hardness, it doesn't look homogeneous.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/DgSX5.jpg&quot; alt=&quot;rock&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2iI7V.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="13555" LastEditorUserId="595" LastEditDate="2018-08-06T08:56:10.707" LastActivityDate="2018-08-06T14:13:29.980" Title="What type of yellow-green stone is this?" Tags="|rocks|crystals|" AnswerCount="2" CommentCount="3" ClosedDate="2019-09-07T00:41:08.950" ContentLicense="CC BY-SA 4.0" />
  <row Id="14783" PostTypeId="2" ParentId="14782" CreationDate="2018-08-05T20:25:59.667" Score="0" Body="&lt;p&gt;Probably Scottish Green Marble or Norwegian Jade (Lizardite) ... Are there any informations about the location where it was found? &lt;/p&gt;&#xA;" OwnerUserId="13398" LastActivityDate="2018-08-05T20:25:59.667" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14786" PostTypeId="1" CreationDate="2018-08-06T02:54:25.210" Score="1" ViewCount="34" Body="&lt;p&gt;I want to be involved in paleontology or archaeology but I don't intend to go back to school for either. I am aware of some opprotunities to volunteer on field studies but am hoping for more resources. Also, I am an analytical chemist by profession. Is this a skill that is valued in these fields that may allow me to be more involved or even get a job? &lt;/p&gt;&#xA;" OwnerUserId="13559" LastActivityDate="2018-08-06T02:54:25.210" Title="How to be involved in paleontolgy as a non-earth scientist" Tags="|paleontology|archaeology|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14787" PostTypeId="5" CreationDate="2018-08-06T04:00:48.410" Score="0" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Graptolithina&quot; rel=&quot;nofollow noreferrer&quot;&gt;Graptolite&lt;/a&gt;s are important &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_index_fossils&quot; rel=&quot;nofollow noreferrer&quot;&gt;index fossil&lt;/a&gt;s of the Paleozoic Era, found from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cambrian&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cambrian&lt;/a&gt; through the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mississippian_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt; Lower Carboniferous&lt;/a&gt;.  Originally described by &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Carl_Linnaeus&quot; rel=&quot;nofollow noreferrer&quot;&gt;Linnaeus&lt;/a&gt; as a category of forms he considered pseudo-fossils, they were later associated with certain colonial &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Pterobranchia&quot; rel=&quot;nofollow noreferrer&quot;&gt;pterobranch&lt;/a&gt; animals. They are believed extinct, although some believe that some extant pterobranch groups such as &lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Rhabdopleurida&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rhabdopleura&lt;/a&gt;&lt;/em&gt; are actually graptolites. Use this tag for questions&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;about graptolite fossils and their use in Paleozioc dating&lt;/li&gt;&#xA;&lt;li&gt;about the lifecycles, anatomy, ecology, and evolutionary history of the animals that formed these fossils&lt;/li&gt;&#xA;&lt;li&gt;about graptolites' possible survival to the present time.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2018-08-06T10:27:59.310" LastActivityDate="2018-08-06T10:27:59.310" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14788" PostTypeId="4" CreationDate="2018-08-06T04:00:48.410" Score="0" Body="Use when discussing these important Paleozioc index fossils, or the animals that formed them." OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2018-08-06T10:27:53.003" LastActivityDate="2018-08-06T10:27:53.003" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14789" PostTypeId="2" ParentId="14761" CreationDate="2018-08-06T11:49:23.473" Score="2" Body="&lt;p&gt;Your rock is probably a piece of a sedimentary concretion.  I have collected rocks that look very similar from western South Dakota.  The yellow crystals are most likely calcite.  The dark brown colored material is also probably calcite and but might be barite.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Acid testing using HCL should confirm if the yellow and brown area are calcite.&#xA;It will probably be difficult to perform an accurate specific gravity measurement for the rock.  My experience is that concretions are commonly quite dense (denser than calcite/dolomite) due to presence of denser minerals such as ankerite, dolomite, barite, celestite, fluorite, marcasite, pyite, sphalerite, siderite, wurzite, and galena as microscopic inclusions hidden within the matrix material.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Concretion&quot; rel=&quot;nofollow noreferrer&quot;&gt;Concretions definition from wikipedia.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2018-08-06T11:49:23.473" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14790" PostTypeId="2" ParentId="14782" CreationDate="2018-08-06T14:13:29.980" Score="1" Body="&lt;p&gt;I think your mineral specimen is smithsonite based on texture and the dark metallic specks that appear to be galena.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2018-08-06T14:13:29.980" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14791" PostTypeId="1" AcceptedAnswerId="14794" CreationDate="2018-08-06T16:09:27.577" Score="3" ViewCount="44" Body="&lt;p&gt;I have been busy learning the components of various minerals for upcoming test....is there any way to predict the components or properties of a mineral just by knowing it's name?&#xA;Eg: albite,augite, labradorite,biotite,anorthite&lt;/p&gt;&#xA;" OwnerUserId="13560" LastEditorUserId="13560" LastEditDate="2018-08-07T07:30:24.350" LastActivityDate="2018-08-07T07:30:24.350" Title="What can one come to know about a mineral just by knowing name" Tags="|geology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14793" PostTypeId="2" ParentId="14791" CreationDate="2018-08-06T18:01:56.960" Score="0" Body="&lt;p&gt;No. The names are all over the place. Some are historic. Some are named after locations. Others are named after people. And although they might be standardised, the original words are often from different languages.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sometimes the names do describe properties - graphite (used for writing), olivine (usually an olive colour), magnetite (is magnetic), etc.&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2018-08-06T18:01:56.960" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14794" PostTypeId="2" ParentId="14791" CreationDate="2018-08-06T18:05:23.293" Score="4" Body="&lt;p&gt;It depends, most of the mineral names we use are derived from old Greek names that were basically comments on the appearance or behaviour of the materials so Galena means literally Lead Ore, which it is, Cassiterite is an ancient word for tin, which it is still be main ore of up to the modern day. On the other hand Pyrite means on fire due to its ancient use as a spark source and Hematite simply means blood and is a comment on the colour of certain European deposits. So if you brush up on your Greek you can tell some things about some minerals but others will remain quite opaque.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-08-06T18:05:23.293" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14797" PostTypeId="1" CreationDate="2018-08-06T20:57:47.643" Score="1" ViewCount="997" Body="&lt;p&gt;By rotational axis I mean axial tilt or Axial obliquity or 66 1/2 degrees tilt of earth to its orbital. &lt;/p&gt;&#xA;" OwnerUserId="13565" LastEditorUserId="13565" LastEditDate="2018-08-09T19:05:45.213" LastActivityDate="2018-08-09T19:05:45.213" Title="What is the angle between earth's axis of rotation and equator? Are they perpendicular or at 66 1/2 Degrees?" Tags="|earth-rotation|earth-system|equator|axial-obliquity|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14799" PostTypeId="1" AcceptedAnswerId="14807" CreationDate="2018-08-07T03:02:32.830" Score="7" ViewCount="1421" Body="&lt;p&gt;What is the oldest fossil ever found on Earth? Where and when was it found? What was the oldest fossil with a brain with 2 hemispheres ever found?&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorDisplayName="user12525" LastEditDate="2019-08-27T11:17:56.150" LastActivityDate="2019-08-27T11:17:56.150" Title="What is the oldest fossil on Earth?" Tags="|fossils|paleontology|dating|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14807" PostTypeId="2" ParentId="14799" CreationDate="2018-08-08T01:49:41.307" Score="9" Body="&lt;p&gt;The oldest undisputed fossil are Stromatolites, bacterial mats, the &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pubmed/27580034&quot; rel=&quot;nofollow noreferrer&quot;&gt;oldest&lt;/a&gt; of which are dated ay 3.7 billion years ago. The key term here is undisputed, there are other possible fossils but it is very hard to have certainty with chemical or cellular fossils. The oldest uncertain fossils trace back to &lt;a href=&quot;https://www.nature.com/articles/nature21377&quot; rel=&quot;nofollow noreferrer&quot;&gt;4.28 billion years&lt;/a&gt; and are possible bacteria trapped in hydrothermal vent products.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The oldest fossil of a creature with a brain is weird. it is actually several creatures from &lt;a href=&quot;https://en.wikipedia.org/wiki/Ediacaran_biota&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ediacaran biota&lt;/a&gt;. These are also some of the oldest multicellular life fossils, lacking any hard parts fossilization of early small animals is incredibly rare event even considering how rare fossilization already is. There are several bilaterally symmetrical animals capable of movement, this combined with the fact they are more than two cells thick means they almost certainly had a brain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Kimberella&lt;/em&gt; and &lt;em&gt;Spriggina&lt;/em&gt; and their relatives are both almost certainly mobile, with some form of nervous system based on phylogenetic bracketing, others are also likely since the ancestor of chordates may in there somewhere. We know there were moving creatures from the ediacara because we actually have &lt;a href=&quot;https://pubs.geoscienceworld.org/gsa/geology/article-abstract/38/2/123/130173/first-evidence-for-locomotion-in-the-ediacara?redirectedFrom=fulltext&quot; rel=&quot;nofollow noreferrer&quot;&gt;trace fossils&lt;/a&gt; that are consistent with a muscular moving organism like anemone.  &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2018-08-08T15:28:45.387" LastActivityDate="2018-08-08T15:28:45.387" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14808" PostTypeId="1" CreationDate="2018-08-08T07:07:14.113" Score="10" ViewCount="2578" Body="&lt;p&gt;My teacher explained that when wind coming from the ocean gets blocked by a mountain it makes rain on one side of the mountain, like in the image below. This rain leads to the creation of rivers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nJyGO.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nJyGO.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;&lt;sub&gt;(found on &lt;a href=&quot;https://www.google.com/search?hl=en&amp;amp;q=relief%20rainfall%20is%20formed&amp;amp;tbm=isch&amp;amp;tbs=simg:CAQSlgEJzOn96iUL1rAaigELEKjU2AQaBAgVCAsMCxCwjKcIGmEKXwgDEievE4AJywhMzAjhCNUCsROmE80HuDekK5k55jeJK9wpjCubKZo5jSsaMD-umUkpWtJS32PQ-KPM1eEMMK1sfrNZS1lJIzcTf3gtKkbTJDOM5mAtf2BFbEyeLyAEDAsQjq7-CBoKCggIARIEn5ArXww&amp;amp;sa=X&amp;amp;ved=0ahUKEwji3eKT-dzcAhUMPN8KHSlsC3EQwg4IJigA&amp;amp;biw=1600&amp;amp;bih=801#imgrc=vxUDQUOArq1QeM:&quot; rel=&quot;noreferrer&quot;&gt;Google Images&lt;/a&gt; to be on numerous websites, difficult to determine original source)&lt;/sub&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: Why is it that rivers sometimes run from the other side of the mountain inland instead of being on the same side of the mountain where the greater rain happens, traveling back to the sea?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One example of this is when monsoon winds coming from &lt;a href=&quot;https://www.mapsofindia.com/maps/india/hillranges.htm&quot; rel=&quot;noreferrer&quot;&gt;the Arabian Sea hit the Indian Western Ghats, it makes rivers which travel to the east instead of traveling to the west&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="13578" LastEditorDisplayName="user1066" LastEditDate="2018-08-10T04:30:31.000" LastActivityDate="2018-08-10T04:30:31.000" Title="Why do rivers sometimes travel down the opposite side of the mountains from where the rain happens?" Tags="|wind|rainfall|rain|orography|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14809" PostTypeId="1" CreationDate="2018-08-08T07:10:45.800" Score="5" ViewCount="1424" Body="&lt;p&gt;Below is a photo that my son took in Scotland showing the sun and moon at the same time. I immediately noticed this anomaly that the light illuminating the moon could not possibly come from the sun. I sent the photo to 4 University astronomy departments and only one responded and that was Cambridge University which is near where I live. The response came from the department librarian (not an astronomer) who said he had never heard of this before. He gave me two possible solutions, one was was from an engineer (not an astronomer) in which he got confused between perspective and light ray tracing and the other was referring to Einstein's theory of light bending by gravity. I check out Einstein and the effect was so small as to be almost immeasurable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/elFma.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/elFma.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have looked at the various 'complex' explanations for what to me is a very simple model.  What need is there to introduce 'curved planes' and 'starry sky domes' all of which do not exist in reality?&#xA;It is only referred to as an 'illusion' because observation doesn't fit the conventional model hence the complex explanations to try and make it work.&#xA;The anomaly is acknowledged to exist with or without photos. Since everyone believes that the moon is illuminated by the sun then simple normal physics do not seem to work. Either the physics is wrong or the sun does not illuminate the moon. I realise that is a heavy statement!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore I state once again:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The sun and the moon are two objects (like a torch and a football) that are suspended in a 3 dimensional space and size should not matter.&lt;/li&gt;&#xA;&lt;li&gt;The moon/football are illuminated by the sun/torch and a perpendicular line or light ray can be drawn between them.&lt;/li&gt;&#xA;&lt;li&gt;It doesn't matter where in space you choose to view them, a perpendicular line or light ray can still be drawn between them.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;This drawing explains my doubts:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zwQgm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zwQgm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm very surprised that some of you have never noticed it before hence the suggestion asking me to post a video. This is a very common occurrence and I have seen it many many times as I go for my morning walk at about 8.00am every morning. I have never thought of actually tabulating my observations. &lt;/p&gt;&#xA;" OwnerUserId="13550" LastEditorUserId="543" LastEditDate="2021-10-14T04:56:06.877" LastActivityDate="2022-09-08T14:26:14.533" Title="What is this Sun and moon photographic anomaly?" Tags="|sun|astronomy|visualization|earth-moon|" AnswerCount="7" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="14810" PostTypeId="1" AcceptedAnswerId="14840" CreationDate="2018-08-08T08:18:58.333" Score="1" ViewCount="1406" Body="&lt;p&gt;I am wondering the difference between water vapor content and specific humidity to determine the moisture availability in the atmosphere. Which one is more acceptable variable to determine the moisture availability in the atmosphere?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I need to show the moisture availability in the atmosphere in my study. So should I explain it through water vapor content or through specific humidity?  I will explain the rainfall deficiency over a region&lt;/p&gt;&#xA;" OwnerUserId="3194" LastEditorUserId="6" LastEditDate="2018-08-10T09:34:44.000" LastActivityDate="2018-08-10T09:46:08.423" Title="Water vapor content versus specific humidity" Tags="|humidity|water-vapour|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14811" PostTypeId="2" ParentId="14809" CreationDate="2018-08-08T08:53:05.233" Score="21" Body="&lt;p&gt;The apparent anomaly, known as the Lunar Terminator or Moon Tilt Illusion, is indeed a matter of perspective. A brief explanation can be found here: &lt;a href=&quot;http://chrisjones.id.au/MoonIllusion/&quot; rel=&quot;noreferrer&quot;&gt;http://chrisjones.id.au/MoonIllusion/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The essence: 'The illusion occurs when the moon and sun are separated by a wide angle, so that they are perceived relative to the horizon, as if in a panorama. A panoramic photograph is a cylindrical projection. In this projection, most straight lines project as sinusoidal curves. The moon-sun line is curved, unless the moon and sun are on the horizon or directly above one another.'&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A long, technical explananation is in the PDF &lt;a href=&quot;https://www.seas.upenn.edu/~amyers/MoonPaper20June.pdf&quot; rel=&quot;noreferrer&quot;&gt;The moon tilt illusion&lt;/a&gt;. Quoting from page 21:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Modern cameras use lenses whose properties are designed to deliver a rectilinear&#xA;  or curvilinear image.  Rectilinear lenses reduce barrel or pincushion distortion from&#xA;  the image but such lenses are difficult to manufacture for the wide angles (90°&#xA;  and above)  needed  to  record  both  the  sun  and  the  moon  on  a  single  photograph.   A&#xA;  photograph [3]  of  the  moon  and  sun  at  an  azimuth  difference  of  80°&#xA;  containing  a&#xA;  leaning  tower  and  unnaturally  leaning  trees  illustrates  the  difficulty  of  eliminating&#xA;  distortion in a wide-angle photograph&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That reference [3] is to &lt;a href=&quot;http://www.astropix.com/html/l_story/moonill.html&quot; rel=&quot;noreferrer&quot;&gt;A Different Moon Illusion&lt;/a&gt; on Jerry Lodriguss astrophotography site &lt;em&gt;Catching the light&lt;/em&gt; where he shows and explains the exact same situation (picture taken from there):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NOym6.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NOym6.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13579" LastEditorUserId="595" LastEditDate="2018-08-08T13:51:58.183" LastActivityDate="2018-08-08T13:51:58.183" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="14812" PostTypeId="2" ParentId="14808" CreationDate="2018-08-08T10:16:17.430" Score="4" Body="&lt;p&gt;In that image you have displayed you are assuming a 2D flow i.e. in the x and z direction where is x is the direction along the mountain range  which is parallel to the ocean(or sea) and the z is the vertical direction. This is a very simplistic assumption of mountain topography as depending on the context one can have mountain gaps and then the moisture laden winds can assume a 3D flow i.e. in the x,y,z direction( y in this case would be across the mountain). In the specific case you mention namely the Western Ghats there is the famous &lt;a href=&quot;https://en.wikipedia.org/wiki/Palakkad_Gap&quot; rel=&quot;nofollow noreferrer&quot;&gt;Palakkad Gap&lt;/a&gt; which bring in moisture laden winds from the Arabian Sea into rain shadow area(at least from the perspective of the South West Monsoon) and can fill up the river headwater source on the rain shadow region and these rivers then flow from west to east. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly the atmosphere is a continuously stratified fluid and in the orographic context one needs to consider what is called the &lt;a href=&quot;https://en.wikipedia.org/wiki/Froude_number&quot; rel=&quot;nofollow noreferrer&quot;&gt;Froude number&lt;/a&gt;. From a layman's perspective this is a ratio between the inertial forces and gravitational forces that determine the 3D state of the atmosphere.&#xA;From a perspective of the the atmospheric scientist the inertial forces in this case would be horizontal wind field(monsoonal wind) and the gravitational forces are represented by &lt;a href=&quot;https://en.wikipedia.org/wiki/Brunt%E2%80%93V%C3%A4is%C3%A4l%C3%A4_frequency&quot; rel=&quot;nofollow noreferrer&quot;&gt;Brunt Vaisala frequency&lt;/a&gt; and is a angular frequency that tells you how air parcels oscillate vertically in a stratified environment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So assuming the following &#xA;              $$ Fr_n &amp;lt; 1 $$&#xA;what this means the incoming wind from the ocean side is not strong enough the penetrate the mountain barrier and you can have what is called upstream blocking. Often during the monsoon the monsoon trough will spend most of it's time offshore and only give skeletal rainfall to the coastal areas. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the other scenario where the following applies&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$ Fr_n &amp;gt; 1 $$ &#xA;in this case the wind is strong enough to penetrate the mountain barrier and the capping inversion on the Lee side can be broken in many ways(diurnal sensible heating and latent heating and ample moisture) can cause dark cumulonimbus clouds to form on the Lee side and that would certain fill up the river source on the Lee side as well. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a case study Tamil Nadu which is not often a beneficiary of the South West Monsoon and is a rain shadow zone has had a surplus rainfall for the past two  years thanks to the principle explained above. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Thamirabarani_River&quot; rel=&quot;nofollow noreferrer&quot;&gt;Thamirabharani river&lt;/a&gt; feeds off the South West Monsoon as it originates from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Pothigai&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pothigai Hills&lt;/a&gt; on the eastern side of the Western Ghats. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This paper - &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2011RG000365&quot; rel=&quot;nofollow noreferrer&quot;&gt;Houze 2012 Orographic Precipitation &lt;/a&gt; is comprehensive and the specific case of the OP will be covered in figure 3e/3f as well as Figure 30(unblocked flow). &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2018-08-08T12:52:43.163" LastActivityDate="2018-08-08T12:52:43.163" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14813" PostTypeId="2" ParentId="14808" CreationDate="2018-08-08T12:39:56.073" Score="1" Body="&lt;p&gt;I am pretty the real answer is in how well known the waterways are, which distorts perceptions of which side of the mountains really has more flowing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rivers on the &lt;a href=&quot;https://www.youtube.com/watch?v=Tmv_8j_UnTs&quot; rel=&quot;nofollow noreferrer&quot;&gt;leeward&lt;/a&gt; side of mountains typically go on to travel large distances, and so as they continue, tributary waterways gradually merge, and so such rivers end up having gathered water from huge areas, often therefore being very large and wide further down towards their mouthes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the thing is that near the mountains, I believe you'll actually notice that waterways on each side of the ridges are fairly similar... and indeed that that the windward side tends to have if anything more rivers and streams.  It's just they simply don't go very far before reaching the ocean... so they aren't able to merge together from large collections into bigger rivers.  And thus they also aren't very famous because there are so many of them and they're so short and unremarkable in width that people outside the local area just haven't heard of them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I couldn't quickly find great map tools or GIS placefiles for India that would allow us to easily turn enhance the view and select layers so we could highlight the waterways details well.  But &lt;a href=&quot;https://www.openstreetmap.org/#map=10/10.8124/76.4851&quot; rel=&quot;nofollow noreferrer&quot;&gt;OpenStreetMap&lt;/a&gt; at least has water features of many widths and fames included on a map even when zoomed out a fair bit to show the broader balance.  So that allowed a sort of quick snapshot, which I took for around southern Karnataka and nearby areas in the south:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Vp2sP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Vp2sP.png&quot; alt=&quot;OSM waterways&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I then sketched in the rough boundary of the Western Ghats (in brown) using the great &lt;a href=&quot;http://topographic-map.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;Topographic-map.com&lt;/a&gt; and also the rough path of the Kaveri River (which Wikipedia seems to suggest is probably the most well-known river in the region?), as well as some of its sizable tributaries (in blue) within the flatter lands.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But click on it to open the picture full screen and look past those bigger lines I drew on and focus instead on the light blue lines OSM uses to show waterways, I think you'll notice that approaching the mountains, there's plenty of waterways flowing from the western edge of the Ghats to the Arabian Sea.  I very much do wish we had a better map source that could color-code rivers by width, and stand them out more amongst the other geographic features.  But I hope you'll find this clearly enough shows that the rivers aren't nearly all on the eastern side, it's just that the ones there flow such a long way that by Tiruchirappalli, they have merged into one large river... which all those waterways west of the Ghats never get the opportunity to do.  But there's a lot of water flowing down the western sides of the Ghats.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And if you look around the &lt;a href=&quot;https://www.openstreetmap.org/#map=10/10.8124/76.4851&quot; rel=&quot;nofollow noreferrer&quot;&gt;OpenStreetMap display of India at the same zoom&lt;/a&gt;, I believe you'll convince yourself this is the same case up and down the west coast.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And that that is also true in many other places, like in &lt;a href=&quot;https://www.openstreetmap.org/#map=8/-37.184/-71.340&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chile/Peru along the Andes&lt;/a&gt; (where the mighty Amazon flows east).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;More water flows down the near (windward) side of the mountains... the rivers there just aren't able to continue on far enough to become grand rivers and reach fame to be put on the national maps or school quizzes.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2018-08-08T12:39:56.073" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="14814" PostTypeId="1" CreationDate="2018-08-08T14:21:04.547" Score="5" ViewCount="6990" Body="&lt;p&gt;Is there somewhere a map which indicates which areas and cities become sea?&lt;/p&gt;&#xA;" OwnerUserId="8326" LastEditorUserId="11908" LastEditDate="2018-08-10T02:54:31.697" LastActivityDate="2018-08-10T02:54:31.697" Title="How would Earth map look like if all ice melts?" Tags="|climate-change|sea-level|glaciology|ice|glaciation|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14815" PostTypeId="1" AcceptedAnswerId="14837" CreationDate="2018-08-08T14:25:23.170" Score="7" ViewCount="1345" Body="&lt;p&gt;Arabia, Sahara and Southeast China and India all are on the tropic of Cancer yet Southeast China and India are not deserts. I know that India is not a desert because of monsoon wind which causes heavy rain. But China doesn't have that kind of wind. Also Tibet which is in Southwest China is very dry because the moist air doesn't get over the Himalayas. But east of that you would normally expect there to be another big desert, but there isn't. Why is this?&lt;/p&gt;&#xA;" OwnerUserId="13583" LastActivityDate="2018-08-10T04:44:29.573" Title="Why is there no desert in Southeast China?" Tags="|wind|rainfall|rain|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14816" PostTypeId="2" ParentId="14814" CreationDate="2018-08-08T14:39:29.097" Score="7" Body="&lt;p&gt;&lt;a href=&quot;https://calculatedearth.com/index.php&quot; rel=&quot;noreferrer&quot;&gt;Calculated Earth&lt;/a&gt; is one of the better tools for this, you can either zoom in and get various flood stages or set a specific flood stage and see what would flood, it is in metric though so you may need some &lt;a href=&quot;https://www.metric-conversions.org/length/feet-to-meters.htm&quot; rel=&quot;noreferrer&quot;&gt;conversion software&lt;/a&gt; to deal with the units for you, depending how familiar you are with metric.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-08-08T14:39:29.097" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14818" PostTypeId="1" AcceptedAnswerId="14825" CreationDate="2018-08-08T17:37:22.523" Score="1" ViewCount="1201" Body="&lt;p&gt;Is there a map that shows the average oxygen concentration in the atmosphere? Seems to me that it would be where the most plants are but I wonder if population and industry make a difference in oxygen levels in a given area? &lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2018-08-09T03:37:12.687" LastActivityDate="2018-08-09T08:20:35.500" Title="Where on Earth does the atmosphere have the most $O_2$ concentration?" Tags="|atmosphere|evolution|plant|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14819" PostTypeId="1" CreationDate="2018-08-08T17:59:45.460" Score="3" ViewCount="41" Body="&lt;p&gt;Is there any way we can calculate the time when a particular hot spring come into existence? Also I wanted to know what is average time period for a active hot spring in general, whether it can flow for geological time scale or can be only in 100s of years?   &lt;/p&gt;&#xA;" OwnerUserId="6629" LastActivityDate="2018-08-08T18:43:31.913" Title="How we can find hot spring genesis time?" Tags="|water|geothermal-heat|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14820" PostTypeId="2" ParentId="14819" CreationDate="2018-08-08T18:43:31.913" Score="2" Body="&lt;p&gt;The answer to the first question is a maybe, hot-springs often have mineral saturated water that can create layered deposits which may be datable, much like tree rings. If reasonably uniform flow and mineralisation rates can be demonstrated over time then reasonably accurate dating may be possible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to the second question, we have a saying &quot;how long is a piece of string?&quot; meaning there is no universal answer, some springs may be seasonal, only flowing for a few months at any given time, while others may flow continuously for hundreds of years then stop abruptly for no apparent reason. There are no &quot;in general&quot; each and every set of geothermal plumbing is unique.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-08-08T18:43:31.913" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14822" PostTypeId="1" CreationDate="2018-08-08T20:27:35.803" Score="7" ViewCount="843" Body="&lt;p&gt;Suddenly, there is this idea in my mind that if an important effect of global warming is rainfall reduction and drought, is it possible to use volcanoes as water vaporizers (regardless of costs)?&lt;/p&gt;&#xA;" OwnerUserId="13587" LastActivityDate="2022-07-22T20:54:45.497" Title="Is it possible to create clouds by pumping water into volcanoes?" Tags="|geology|hydrology|geoengineering|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14823" PostTypeId="2" ParentId="14822" CreationDate="2018-08-08T23:38:00.390" Score="1" Body="&lt;p&gt;You could generate a lot of steam for a time, but it would require a lava lake like in Hawaii that was constantly refreshing itself or some kind of access to a large consistent magma chamber.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pouring water directly onto a lava lake would probably create an eruption on its own. If the lava cooled enough you would end up with a thick insulating crust and stop getting any steam to make clouds out of it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a stratovolcano (think St Helens) or something less active, maybe you could pump water down and have it come out as steam the same way a geothermal power plant does. The scale would be huge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And in either case, the steam would quickly condense into clouds so you would only get a local effect if you wanted to create rain. And to create rain you'd still need a water source which if you had could be used to irrigate. So you'd have to pump some kind of water to wherever you wanted it to begin with.  Maybe you can get away with seawater for it, but still a long way to pump it where you want to turn it into steam. &lt;/p&gt;&#xA;" OwnerUserId="6656" LastActivityDate="2018-08-08T23:38:00.390" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14825" PostTypeId="2" ParentId="14818" CreationDate="2018-08-09T04:13:09.480" Score="-1" Body="&lt;p&gt;You may find bigger O2 levels at the upper layer of rich oceans -biologically talking-. There is Henry's Law, an equilibrium between gas pressures/concentrations of the ocean and the atmosphere, so you might find it at the contact between an ocean bacterial rich system and the atmosphere, but maybe on arboreal forests at light.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have no data about O2 levels at both suggestions, atmosphere/ocean contact at a rich ocean system &amp;amp; a very rich arboreal forest on hot season. Just a caution for a possibly answer from a botanic. There may be maps about O2 levels at ocean surface but that at NASA and so and I am a student with no access to Science papers Muze and don't know how to get them. For arboreal system they can give you absolute maximum O2 levels registered, and then comparison.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The maximum level will happen at a certain time, and even I think satellites can measure gas levels the layer to search is about 1mm or so. maybe doing a comparison between highest O2 levels measured at the interface of a rich estuary or so and a tropical forest coming from local studies we find a non exactly answer but giving the environment where to find it and an approximate concentration.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are those ozone/O3 layers with a very high concentration at industry zones,but i guess you ask for O2 gas. There are also hyperbolic conditions,eg at a Erlenmeyer flask of a lab, but I guess you are asking for levels on Earth's Atmosphere sensu stricto at a relative big atmosphere's surface/volume. I think others will appreciate more the question if you write eg &quot;higher O2 concentration measured on an Earth's Atmosphere area despite labs or natural micro-layers&quot; or something like that if that's you want to mean. Also sensu stricto more oxygen no matches with saturation (saturation is function of Temperature and Pressure).&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="39" LastEditDate="2018-08-09T08:20:35.500" LastActivityDate="2018-08-09T08:20:35.500" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14826" PostTypeId="2" ParentId="14822" CreationDate="2018-08-09T05:42:20.363" Score="6" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is it possible to create clouds by pumping water into volcanoes?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Maybe, but it's a really bad idea. Here's why:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Volcanoes are unexpected and change with time. You can waste two years building a facility that does it, only for the volcano to cease being active and become dormant. Alternatively, the volcano might blow up and destroy your infrastructure.&lt;/li&gt;&#xA;&lt;li&gt;You actually need lava to do so. Very few volcanoes have persistent lava lakes. Two are in tropical islands (Vanuatu, Hawaii), two are in rainforests (Nicaragua, DRC), one is in Antarctica, and only one is in a desert where it would actually be somewhat useful (Ethiopia).&lt;/li&gt;&#xA;&lt;li&gt;In the absence of a lava lake, you can pump the water into the underground magma chamber and hope that it escapes in the form of steam. This is a bad &lt;em&gt;bad&lt;/em&gt; &lt;strong&gt;bad&lt;/strong&gt; idea, because you can cause a &lt;a href=&quot;https://en.wikipedia.org/wiki/Phreatic_eruption&quot; rel=&quot;nofollow noreferrer&quot;&gt;phreatic&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Phreatomagmatic_eruption&quot; rel=&quot;nofollow noreferrer&quot;&gt;phreatomagmatic&lt;/a&gt; eruption. Here's an example:&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://youtu.be/hjOnh_QRd0A&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://youtu.be/hjOnh_QRd0A&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;4&quot;&gt;&#xA;&lt;li&gt;You need water. If you have fresh water, you better use that water to solve the drought directly instead of pumping it into a volcano. If you're using sea water, you have the problem of laze. At the moment the opposite is happening: Kilauea in Hawaii is erupting lava that reaches the ocean. The reaction between the hot lava and the sea water creates releases acid into the air. &lt;strong&gt;Bad&lt;/strong&gt; idea. Here's how it looks like:&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://youtu.be/8SF5LQO4T_4&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://youtu.be/8SF5LQO4T_4&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;5&quot;&gt;&#xA;&lt;li&gt;If somehow you managed to avoid exploding the volcano or creating acid rain, you would rapidly cool the top layer of the lava, solidifying it into rock. Rock is a poor thermal conductor, so you're forming a lid on top of the lava, making the thing much less effective.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;if an important effect of global warming is rainfall reduction and&#xA;  drought...(regardless of costs)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Just use &lt;strong&gt;desalination&lt;/strong&gt;. A very effective yet expensive way to get fresh water.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="18081" LastEditDate="2019-12-05T14:10:34.423" LastActivityDate="2019-12-05T14:10:34.423" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14829" PostTypeId="1" CreationDate="2018-08-09T17:09:07.860" Score="1" ViewCount="38" Body="&lt;p&gt;Given a 440 acre farm running roughly 200 acres of Crops and 40-50 head of cattle,in the secondary ash zone within the lake of the ozarks reigon of Missouri, how viable would survival be relying on self sufficiency for a family of 4? How would agriculture be able to recover in this reigon? How badly would agriculture be harmed? Absolutely useless or a just a severe cut to food yeild? And how would it be possible to survive all the dust in the air? Also, affects to grazing land and crop land, what would they be, and what methods could be used to recover?&lt;/p&gt;&#xA;" OwnerUserId="13595" LastEditorUserId="725" LastEditDate="2018-08-10T08:35:53.200" LastActivityDate="2018-08-10T08:35:53.200" Title="Agricultural self sufficiency after yellowstone eruption?" Tags="|volcanology|homework|agriculture|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14832" PostTypeId="1" AcceptedAnswerId="14848" CreationDate="2018-08-09T18:48:42.850" Score="5" ViewCount="5590" Body="&lt;p&gt;Observing many photos of mountains one can assume that most of the mountains are grey or brown. See also &lt;a href=&quot;https://en.wikipedia.org/wiki/Mountain&quot; rel=&quot;nofollow noreferrer&quot;&gt;the mountain article&lt;/a&gt; at Wikipedia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are however several ways &lt;a href=&quot;https://en.wikipedia.org/wiki/Mountain_formation&quot; rel=&quot;nofollow noreferrer&quot;&gt;a mountain can form&lt;/a&gt;, which allow for exposure of various rocks, still mountains are mostly grey/brown.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is it so? &#xA;Why isn't there a single mountain out of &lt;a href=&quot;https://en.wikipedia.org/wiki/Olivine&quot; rel=&quot;nofollow noreferrer&quot;&gt;Olivine&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Pyrite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pyrite&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Tourmaline&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tourmaline&lt;/a&gt; or, say, &lt;a href=&quot;https://en.wikipedia.org/wiki/Autunite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Autunite&lt;/a&gt;, or any other brightly coloured rock?&lt;/p&gt;&#xA;" OwnerUserId="13598" LastEditorUserId="13598" LastEditDate="2018-08-10T20:55:42.120" LastActivityDate="2021-07-22T17:34:28.660" Title="Why are the mountains predominately grey or dark brown?" Tags="|geology|mountains|geomorphology|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14833" PostTypeId="2" ParentId="14832" CreationDate="2018-08-09T19:47:00.910" Score="3" Body="&lt;p&gt;Color of mountains is due to rock composition and vegetation.&#xA;Very common rock colors are grey and brown for igneous, sedimentary and metamorphic rocks.  In higher elevations, predominant trees are conifers which are commonly dark greens. Also, by contrast with sky above, most mountains appear darker &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are colorful mountains though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Rainbow Mountains of China within the &lt;a href=&quot;https://www.forbes.com/sites/trevornace/2016/03/02/rainbow-mountains-china-earths-paint-palette/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zhangye Danxia Landform Geological Park&lt;/a&gt;.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/a6DHW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/a6DHW.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/UWqxr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UWqxr.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.garnetminetours.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gore mountain in New York&lt;/a&gt; is not exclusively composed of garnet but is one of the largest garnet deposits on earth.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/koqlU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/koqlU.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.gamineral.org/ft/commercial/ftgravesmain.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Graves Mountain  in Georgia, USA&lt;/a&gt; is largerly composed of aluminum silicates minerals like kyanite, sillimanie, and Pyrophyllite.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/kOebP.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kOebP.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Personally, I was amazed how much Mars and Titan looked like areas in the Mohave desert I have visited. &lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="6" LastEditDate="2018-08-10T10:13:28.043" LastActivityDate="2018-08-10T10:13:28.043" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14835" PostTypeId="2" ParentId="14814" CreationDate="2018-08-10T02:46:35.020" Score="2" Body="&lt;p&gt;The latest estimations of global land ice mass suggest they have enough water to &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/B9780444635242000051&quot; rel=&quot;nofollow noreferrer&quot;&gt;rise sea level in 66.5 m&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With this value you can go on and produce a global map (or one of you area of interest) at &lt;a href=&quot;https://calculatedearth.com/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Calculated Earth&lt;/a&gt; as @Ash suggested. I agree is a good tool.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've created an animated GIF using two maps produced at &lt;a href=&quot;https://calculatedearth.com/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Calculated Earth&lt;/a&gt; with current sea level and +66.5m, so you can easily see the changes:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/lqZsW.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lqZsW.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.nationalgeographic.com/magazine/2013/09/rising-seas-ice-melt-new-shoreline-maps/&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Geographic maps&lt;/a&gt; (suggested by @Gimelist) are very nice too, and are based in a slightly different figure of 65.8 m (216 ft).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that this is just a thought experiment, because the melting of all land ice would have to be encompassed by a significant increase in temperature. Such increase in temperature would also produce a very important sea level rise due to thermal expansion. The magnitude of that rise depends on the temperature rise and the time scale, as the oceans take in the order of millennia to equilibrarte with changes in atmospheric conditions.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-08-10T02:51:49.417" LastActivityDate="2018-08-10T02:51:49.417" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14837" PostTypeId="2" ParentId="14815" CreationDate="2018-08-10T04:44:29.573" Score="1" Body="&lt;p&gt;This is a very active region for tropical storms.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/i5rYz.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/i5rYz.gif&quot; alt=&quot;https://eoimages.gsfc.nasa.gov/images/imagerecords/7000/7079/tropical_cyclone_map_lrg.gif&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://earthobservatory.nasa.gov/images/7079/historic-tropical-cyclone-tracks&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2018-08-10T04:44:29.573" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14838" PostTypeId="1" CreationDate="2018-08-10T08:12:51.193" Score="7" ViewCount="293" Body="&lt;p&gt;This question is linked to the following &lt;a href=&quot;https://earthscience.stackexchange.com/questions/150/what-are-the-ramifications-to-life-on-earth-when-the-earths-magnetic-poles-swit&quot;&gt;question&lt;/a&gt;, and has two parts.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Mars interdicts approximately 40% of the radiation (per square meter) of the sun that Earth does. It has been claimed that Mars is unsustainable to human life, in part due to the particle radiation from the solar wind, such that a four year round trip to Mars is likely to cause cancer and/or permanent damage to the genome etc.  Why does a pole reversal, which typically takes 1000 years, not have a period of radiation that is intolerable to life? &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Not only do migratory birds require the magnetic pole for direction, certain bacteria/algae do to rise and fall in the oceans correctly.  If the pole reversal is not very quick, why do bird migrations not go askew in major numbers. (P.S. I am a little skeptical of the learned landscape proposal found in the linked question - is there evidence for a similar lateral paths taken by birds, year on year, to prove they are recognizing landscapes? Landscapes and features change very quickly over distance. And if so, does the magnetic direction sense really help the migration? Also, when it does reverse, if magnetic field is a key component to knowing direction, then won't that tend to drive them in the opposite direction, so even a quick final phase of a reversal may result in a large number of missing birds.)  Also, why doesn't the food chain collapse when microbial creatures start to dive deeper when they used to head to the surface as a result of their magnetic compass?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="13603" LastEditorUserId="11908" LastEditDate="2019-03-11T20:59:28.590" LastActivityDate="2019-03-11T20:59:28.590" Title="Why are pole reversals not more detrimental to life?" Tags="|geophysics|geomagnetism|mass-extinction|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14839" PostTypeId="2" ParentId="14832" CreationDate="2018-08-10T08:43:59.613" Score="3" Body="&lt;p&gt;As Gary Kindel in his answer correctly said, mountains may consist of either magmatic, metamorphic or sedimentary rocks or all three together.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The greyish to brownish color is thus due to a mixture of all sorts of rocks and minerals that is covered by layers of eroded material of different grain sizes. This way, mountains appear to be of a single color when observed from a distance. This is similar to &lt;a href=&quot;https://www.wikihow.com/Make-Gray&quot; rel=&quot;nofollow noreferrer&quot;&gt;mixing a couple of watercolors together&lt;/a&gt; - the result will either be a greyish or a brown color. However, if we would magnify the watercolor mixture under a microscope, so that we see the individual pigments, we could tell that it isn't actually grey/brown. Same applies to the mountains. From a far, they appear to be grey/brown but when you get closer you can depict all sorts of colors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only exceptions to this are mountains, where the material is very well stratified, so that different colors can be seen from a distance.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer your second question: Please note that Olivine, Pyrite and Tourmaline are not rocks but minerals. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Olivine&lt;/strong&gt; is mostly abundant in earth's mantle (check out &lt;a href=&quot;https://en.wikipedia.org/wiki/Mohorovi%C4%8Di%C4%87_discontinuity&quot; rel=&quot;nofollow noreferrer&quot;&gt;Moho&lt;/a&gt;). The chance that a mountain is build solely by a material from the mantle is highly unlikely. What happened to the material that was on top? Secondly, Olivine is not stable at earth's surface according to the Goldich dissolution series. It alters into clay minerals and iron oxides that are easily eroded by e.g. rainwater. Thus, if there was a mountain made of olivine it would have surely been eroded by now. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Tourmaline&lt;/strong&gt; is a mineral that forms in &lt;a href=&quot;https://en.wikipedia.org/wiki/Pegmatite#Mineralogy&quot; rel=&quot;nofollow noreferrer&quot;&gt;pegmatites&lt;/a&gt; and is thus far too rare to form an entire mountain. Especially since there is no process that individually picks Tourmalines from nature to build a mountain out of it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Pyrite&lt;/strong&gt;; there is still a great debate in the literature about the formation processes of Pyrite. But it is most likely a mineral that forms in a secondary process due to the intrusion of hydrothermal mineral-rich water. Thus, Pyrite is not concentrated in one area and is, like Tourmaline, far too rare to form a mountain.&lt;/p&gt;&#xA;" OwnerUserId="13604" LastActivityDate="2018-08-10T08:43:59.613" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14840" PostTypeId="2" ParentId="14810" CreationDate="2018-08-10T09:46:08.423" Score="2" Body="&lt;p&gt;For a study relating to rainfall, I would be inclined to look at &lt;strong&gt;total column water vapour (TCWV)&lt;/strong&gt;, also known as &lt;strong&gt;integrated water vapour (IWV)&lt;/strong&gt; or &lt;strong&gt;precipitable water&lt;/strong&gt;.  They're all (more or less) the same thing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The company &lt;a href=&quot;http://www.remss.com/measurements/atmospheric-water-vapor/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Remote Sensing Systems&lt;/a&gt; describes it as:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Total column water vapor is a measure of the total gaseous water contained in a vertical column of atmosphere. It is quite different from the more familiar relative humidity, which is the amount of water vapor in air relative to the amount of water vapor the air is capable of holding. Atmospheric water vapor is the absolute amount of water dissolved in air.  When measured in linear units (millimeters, mm), it is the height (or depth) the water would occupy if the vapor were condensed into liquid and spread evenly across the column. Using the density of water, we can also report water vapor in kg/m2 = 1 mm or g/cm2 = 10 mm.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;For rain to form, clouds need to form first.  Clouds need cloud condensation nuclei, but crucially, for clouds to form, the water vapour partial pressure needs to reach the saturation vapour pressure.  The latter is strongly dependent on temperature (Clausius-Clapeyron relation), so a profile of relative humidity is not the most directly useful quantity.  The total column water vapour describes how much liquid water might form, which is why it is sometimes even described as precipitable water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can get this product either from reanalysis (like ERA-5) or retrieved from hyperspectral infrared sounders, such as IASI, AIRS, or CrIS.  Depending on where and when in the world you're looking at, there may also exist products from geostationary instruments.&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2018-08-10T09:46:08.423" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14841" PostTypeId="2" ParentId="12093" CreationDate="2018-08-10T13:22:05.187" Score="1" Body="&lt;p&gt;The &lt;em&gt;Milne-Eddington approximation&lt;/em&gt; lets you account for greenhouse gases, because they increase the longwave &lt;em&gt;optical thickness&lt;/em&gt; &lt;span class=&quot;math-container&quot;&gt;$\tau$&lt;/span&gt; of the atmosphere:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$T_s = T_e \cdot \left(1 + \frac{3}{4} \tau\right)^{\frac{1}{4}}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$T_s$&lt;/span&gt; is surface temperature and &lt;span class=&quot;math-container&quot;&gt;$T_e$&lt;/span&gt; is effective temperature (from sunlight and albedo alone).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\tau$&lt;/span&gt; can be found from curve fits to the partial pressures of the greenhouse gases involved.  An example of a temperature model including greenhouse gases can be found here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://saspcsus.pbworks.com/w/file/fetch/64696386/planet%20temperatures%20with%20surface%20cooling%20parameterized.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;B.P. Levenson - Planet temperatures with surface cooling parameterized&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12453" LastEditorUserId="17656" LastEditDate="2019-09-17T07:32:55.163" LastActivityDate="2019-09-17T07:32:55.163" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14843" PostTypeId="2" ParentId="14838" CreationDate="2018-08-10T16:01:11.587" Score="2" Body="&lt;p&gt;National Geographic published an article about this in January 2018 - &lt;em&gt;&lt;a href=&quot;https://news.nationalgeographic.com/2018/01/earth-magnetic-field-flip-north-south-poles-science/&quot; rel=&quot;nofollow noreferrer&quot;&gt;No, We're Not All Doomed by Earth's Magnetic Field Flip&lt;/a&gt;&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, the flipping of the magnetic poles does take a long time - thousands of years. But during the change, the Earth's magnetic field does not cease to exist &amp;amp; the magnetic poles do not disappear. They slowly migrate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For argument sake, the north magnetic pole might be centered in Canada, then slowly move to the US, Mexico, Ecuador, Chile and then be located over Antarctica. The south magnetic pole will always be in a position opposite to the location of the north magnetic pole, wherever it may be.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth will have a magnetic field but,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Earth’s magnetic field could get weaker—but its strength is already quite variable, so that’s not necessarily unusual, and there’s no indication it will vanish entirely, according to NASA. Why? Because it never has.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;However, if the magnetic field gets substantially weaker and stays that way for an appreciable amount of time Earth will be less protected from the oodles of high-energy particles that are constantly flying around in space. This means that everything on the planet will be exposed to higher levels of radiation, which over time could produce an increase in diseases like cancer.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;During the prolonged change, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;animals that use Earth’s magnetic field for navigation—including birds, salmon, and sea turtles—could get lost during their routine journeys. Eventually they will sort this out, and all other things being equal, life will go on. Lots of doomsday prophets have tried to equate geomagnetic flips with mass extinctions, but the data just aren’t there.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-08-10T16:01:11.587" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14844" PostTypeId="2" ParentId="14838" CreationDate="2018-08-10T16:49:39.430" Score="6" Body="&lt;p&gt;There are several factors to consider. The main one is the atmosphere (especially if you want to compare Mars with the Earth's during magnetic reversals). Earth's atmosphere is a formidable shield against solar wind and cosmic radiation. Each type of radiation have a different penetration, but in general the radiation dose associated to each type of radiation decays exponentially at lower elevations. For example for ionizing radiation the relationship is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$E(z)=E_0 \left(0.21 e^{-1.649 z} + 0.79 e^{-0.4528 z}\right)$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where $E$ is the dose, $E_0$ is the dose ate sea level and z is the altitude (&lt;a href=&quot;http://www.unscear.org/docs/reports/2008/09-86753_Report_2008_Annex_B.pdf&quot; rel=&quot;noreferrer&quot;&gt;reference&lt;/a&gt;). The following figure illustrate how the radiation dose drop at lower elevations. But if you extend that curve to 100 km you will be able to grasp how much of the incoming radiation is filtered by the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mGzAk.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mGzAk.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Figure: Cosmic radiation exposure as a function of altitude, latitude 50° north, taken from the &lt;a href=&quot;https://www.euronuclear.org/info/encyclopedia/r/radiation-exposure-cosmic.htm&quot; rel=&quot;noreferrer&quot;&gt;European Nuclear Society&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore even in the absence of magnetic field, only a small fraction of the radiation would make it to the surface. And note that reversals only means a weakening of the magnetic field, not a complete disappearance. What can disappear is the dipole component of the magnetic field, not the magnetic field as a whole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is important to note also that the magnetic field is very important to prevent atmospheric erosion. Therefore, a permanent lack of magnetic field can generate the loss of the atmosphere (likely what happened to Mars). Conversely, Earth's magnetic field is one of the reasons we have a very thick atmosphere compared to Mars, and during the brief periods of magnetic field weakening (due to pole reversals), our thick atmosphere still provided a quite effective protection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fact that space radiation doesn't penetrate much can be observed in many different ways, one of them is noting that &lt;a href=&quot;https://en.wikipedia.org/wiki/Aurora&quot; rel=&quot;noreferrer&quot;&gt;auroras&lt;/a&gt; (a.k.a. northern lights) usually never happen below 90 km of elevation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Moreover, the reason why auroras happen only at high latitudes (i.e. near the poles), is due to the &quot;geomagnetic latitude effect&quot; that describe how radiations dose rates are minimal at the equator and maximal at the geomagnetic poles. Nevertheless, the atmosphere absorbs most of that extra radiation and life thrives in the arctic forest without any problems.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, the atmosphere would not be just a passive filter, it could create its own magnetic field as some studies suggest. Such studies argue that as long as we have atmosphere, the solar wind can induced a magnetic field around the Earth even in the absence of internal magnetic field (&lt;a href=&quot;https://arxiv.org/abs/astro-ph/0404580&quot; rel=&quot;noreferrer&quot;&gt;reference&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other important point is: Would the paleontologic record of migratory birds populations and magnetic-dependant microbial life be good enough to detect a catastrophic population reduction on migratory birds and some microbial life that happened 780,000 years ago? I'm not an expert but I would be skeptical. In fact, 780,000 years seems to be enough time for the evolution whole new species and the rise of the migratory behaviour from scratch. More recent reversal events like the &lt;a href=&quot;https://en.wikipedia.org/wiki/Laschamp_event&quot; rel=&quot;noreferrer&quot;&gt;Laschamp event&lt;/a&gt; 41,000 years ago were much quicker than 1,000 years, and even so, I wonder how well we could reconstruct migratory birds populations that far back (considering that we have trouble reconstructing human populations back then).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding migratory birds, you say that after the reversal the birds would migrate in the wrong direction. And that is quite questionable. In the lack of any point of reference, using an improvised compass to know the north-south direction is easy, but figuring out which side is north and which is south is much more difficult. Therefore, maybe birds use other means to figure that out which side of their compasses is north, means that don't depend on the magnetic field. For example, the side at which sunrise happen or something like that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, microbes evolve and adapt very quickly, so even assuming that some (or many) of them would die during reversals, I'm sure others would take their place. At the end the ocean microbiota is nutrient-limited, and all the nutrients not used by the dying species will be used by other species that can thrive with a weaker magnetic field. So I wouldn't be so quick to think that such event would lead to a food chain collapse.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-08-10T20:18:09.913" LastActivityDate="2018-08-10T20:18:09.913" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14846" PostTypeId="2" ParentId="14370" CreationDate="2018-08-10T21:48:33.550" Score="5" Body="&lt;p&gt;As others have pointed already in the comments, there is no earthquake data extending that far back. But we do have data for the last century. In a similar way to my answer to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13131/is-there-any-correlation-between-grand-solar-minimums-gsm-and-earthquakes?rq=1&quot;&gt;this question&lt;/a&gt;. Here I've plotted the yearly count of all of the earthquakes worldwide from 1900 to 2018 of magnitude greater of 7,7.5, 8, or 8.5 found in the &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/search/&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS Earthquake Catalog&lt;/a&gt; that span back to year 1900 (bars), along with the total number of sunspots per year from the &lt;a href=&quot;http://www.sidc.be/silso/datafiles#total&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sunspot Index and Long-term Solar Observations&lt;/a&gt; (red line).  Here is the resultant graph:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FFhVs.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FFhVs.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, there is not any significant correlation between frequencies of large earthquakes of any size and the solar activity. The solar record shows the well-proven 11 year solar cycle (actually &lt;a href=&quot;https://scied.ucar.edu/sunspot-cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;it's a 22 year cycle&lt;/a&gt; with two similar halves). On the other hand, the earthquakes show no clear pattern.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, for the grand minimums like Maunder and Dalton's solar minimums we do not have a reliable earthquake record. Nevertheless, given that EVERYTHING we know about physics and earthquakes suggest that there is NO mechanism by which solar activity could possibly influence earthquakes. And provided that there is no evidence of such correlation in the 100+ years of the instrumental record. There is absolutely no reason to believe that such correlation exist. The answer to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13131/is-there-any-correlation-between-grand-solar-minimums-gsm-and-earthquakes?rq=1&quot;&gt;this question&lt;/a&gt; should be informative too.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-08-11T02:58:18.880" LastActivityDate="2018-08-11T02:58:18.880" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14847" PostTypeId="1" CreationDate="2018-08-10T22:30:48.240" Score="0" ViewCount="178" Body="&lt;p&gt;Putting aside burning fossil fuels, what are the consequences of another 100 years of drilling deeper and deeper to extract oil reserves globally?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would this significant extraction remove an insulation layer of the core's heat enabling for heat to rise more freely towards the crust?  How much would this effect the earth's ground temperature?&lt;/p&gt;&#xA;" OwnerUserId="13609" LastActivityDate="2018-08-11T19:33:58.357" Title="Could further oil drilling remove an insulation layer of the Earth cores heat?" Tags="|temperature|drilling|" AnswerCount="1" CommentCount="2" ClosedDate="2018-08-11T16:54:14.523" ContentLicense="CC BY-SA 4.0" />
  <row Id="14848" PostTypeId="2" ParentId="14832" CreationDate="2018-08-11T05:08:12.713" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;...which allow for exposure of various rocks, still mountains are mostly grey/brown.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The colourful minerals are apparent when you look up close. When you look from far away, the minerals are all mixed in your vision. My 2-year old daughter prepared a wonderful example of how this works:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iX4sd.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iX4sd.jpg&quot; alt=&quot;Colours&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take a bunch of beautiful bright water colours, mix them together, and you end up having a greyish brown, dull colour.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take another example. Sand, or sandstone. Boring yellow, white, or brown. But it's basically quartz. Finely divided quartz, unlike any of the beautiful quartz crystals you see for sale. Grain size is an important factor of the perception of colour.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;That said, one of the skills geology undergraduates learn in their first year of university, is distinguishing colours in a geological context. What to the untrained eye may seem brown or grey, appears like a world of colour. I still remember that when I just started my geology B.Sc about 10 years ago, we were given a bunch of rocks that all looked grey. After one year, they did not look grey any more. They were red-grey, brown-grey, &lt;a href=&quot;https://www.google.com/search?tbm=isch&amp;amp;q=blueschist&amp;amp;tbs=imgo:1&quot; rel=&quot;nofollow noreferrer&quot;&gt;blue-grey&lt;/a&gt;, &lt;a href=&quot;https://www.google.com/search?tbm=isch&amp;amp;q=greenschist&amp;amp;tbs=imgo:1&quot; rel=&quot;nofollow noreferrer&quot;&gt;green-grey&lt;/a&gt;, etc.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Mountains can be coloured. Here are some pictures that I took myself a while ago:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KeduI.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KeduI.jpg&quot; alt=&quot;Ardon&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JNN1E.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JNN1E.jpg&quot; alt=&quot;Roded&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On a closer look I'm certain you will see that there are many colours in there: green, yellow, orange, pink, red, brown, white, black. No need for geological education to see that.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Why isn't there a single mountain out of Olivine, Pyrite, Tourmaline&#xA;  or, say, Autunite, or any other brightly coloured rock?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Most rocks are not composed of a single mineral. However, there are rocks composed only of olivine. They're call &quot;dunites&quot;. Here's one:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YjiTM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YjiTM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See the rock behind? It's brown. That's because olivine contains ferrous iron. Once it's exposed to atmospheric oxygen, it becomes ferric iron. A better known name for ferric iron is &quot;rust&quot;. This is generally the case for a lot of minerals. Colours commonly arise because of transition metals in a more reduced cationic state. Higher oxidation states are usually black, grey, red, and all kinds of earthy colours. The boring colours you see are commonly the result of &quot;rusting&quot; of rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is also the case for pyrite. It is an iron sulfide - shiny yellow. When exposed to the atmosphere, it rusts. In fact, patches of red soil in otherwise non-red soil are an indicator for a hidden ore deposit (&lt;a href=&quot;https://en.wikipedia.org/wiki/Gossan&quot; rel=&quot;nofollow noreferrer&quot;&gt;gossan&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-08-11T05:08:12.713" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14849" PostTypeId="1" AcceptedAnswerId="14853" CreationDate="2018-08-11T06:46:30.320" Score="6" ViewCount="385" Body="&lt;p&gt;Most statistics about climate change are based on climate data over the last 150 year (as long as records have been kept). This seems irrelevant in terms of the geological time scale of temperature variation on the earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the last 400 million years, has there ever been a 200-year interval during which the rate of climate change was as great as it is today?&lt;/p&gt;&#xA;" OwnerUserId="13611" LastEditorUserId="11908" LastEditDate="2019-04-06T20:06:38.640" LastActivityDate="2019-04-06T20:06:38.640" Title="Geological evidence about climate change: has there ever been a period with a rate of climate change as great as it is today?" Tags="|geology|climate-change|climate|paleoclimatology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14852" PostTypeId="2" ParentId="14847" CreationDate="2018-08-11T16:39:34.183" Score="1" Body="&lt;p&gt;I think your basic assumption is incorrect. Removing oil and the 80 to 90% water associated with it would reduce the thermal conductivity of the rock formations. It removes these liquids which aid thermal conductivity across the myriad of very tiny pores that contained the liquids. In the US regulations have the affect of the water being pumped back into the ground , not necessarily into the same formation. Outside the US that is not generally the case. Without doing any arithmetic, this appears to be a minuscule affect on earth temperature.....Thinking about it a little , you could likely make a better case on the basis  of the heat in the produced fluids ( water ,oil, gas): I know difficult wells go into formations that are 400 F+ , overall average the average temperature of production is likely between 200 and 300 F. No doubt SPE has real data but I am no longer a member. &lt;/p&gt;&#xA;" OwnerUserId="8409" LastEditorUserId="8409" LastEditDate="2018-08-11T19:33:58.357" LastActivityDate="2018-08-11T19:33:58.357" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14853" PostTypeId="2" ParentId="14849" CreationDate="2018-08-11T16:57:39.597" Score="6" Body="&lt;p&gt;Quick answer: yes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But please read the following comments and explanations:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most statistics about climate change are not based only in the 150 years of instrumental records. We have many good temperature proxies that go back between a millennia and 70 million years. Among them: tree rings, growth bands in corals, layered marine sediments, bog and lake sediments, stalagmites and stalactites, ice cores (800,000+ years), and isotopic composition of shells of single-cell organism called foraminifera. This last one can be used to estimate the temperature of the deep ocean as far back as 70 million years.&#xA;Although, the interpretation of the isotopic composition could be tricky, the caveats do not change the general picture presented by this long term temperature record. Here is a reconstruction of temperature based on foraminifera shells.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fpzVr.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fpzVr.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see that there were long periods of time with temperatures much higher than today. However, when it come to the rate of change this record doesn't have the resolution to answer your question. &#xA;As a first remark, note that we don't have a reliable temperature record going 400 million years back, and for the ones that do extend multiple million years, the resolution is not good enough to see quick climate change events as the one we are experiencing now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, we don't need to go that far back to find climatic changes greater than the one we are experiencing today. Such changes are actually visible in the 800,000 years records recovered from antarctic ice cores. And actually, the best examples come from high-resolution Greenland ice cores that go only about 110,000 years into the past.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the most studied quick climate changes is the one after the &lt;a href=&quot;https://en.wikipedia.org/wiki/Younger_Dryas&quot; rel=&quot;noreferrer&quot;&gt;Younger Dryas&lt;/a&gt; about 12,000 years ago. Considering changes in the chemical composition of the atmosphere, and proxies of temperature, the data suggest that climate change after the &lt;a href=&quot;https://en.wikipedia.org/wiki/Younger_Dryas&quot; rel=&quot;noreferrer&quot;&gt;Younger Dryas&lt;/a&gt; and other previous ones were more dramatic than the cumulative changes in the last 200 years. And such dramatic changes happened in periods as short as 40 years. The end of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Younger_Dryas&quot; rel=&quot;noreferrer&quot;&gt;Younger Dryas&lt;/a&gt; was associated to changes in temperature of 8 °C or maybe up to 15°C regionally, accompanied by two-fold changes in precipitation and methane concentrations (&lt;a href=&quot;http://www.pnas.org/content/97/4/1331&quot; rel=&quot;noreferrer&quot;&gt;reference 1&lt;/a&gt;, &lt;a href=&quot;https://www.nature.com/articles/34346&quot; rel=&quot;noreferrer&quot;&gt;reference 2&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately the second reference (a Nature paper) is behind a paywall so I'll add here figure 4, the most relevant to this question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Ukbaz.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ukbaz.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see how fast are the changes in methane concentrations and $\delta^{18}O$. As a rough reference, a change of one unit in $\delta^{18}O$ is equivalent to a change in temperature of 2 °C, therefore the big jump in the figure is about 10°C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now I could argue that given that agriculture appeared just after that change (~12,000 years ago). When assessing if we have faced in the past a climate changes as dramatic as the one we are observing now you have to focus on what happened after that time. And notably, since then, the climate have been very stable. In fact, the change we are experiencing now is the largest after the invention of agriculture (previous references and &lt;a href=&quot;https://www.bas.ac.uk/data/our-data/publication/ice-cores-and-climate-change/&quot; rel=&quot;noreferrer&quot;&gt;this one&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a corollary, it is important to realize that Earth's climate is much more chaotic and capable of large changes in short periods that what you would think by looking at the written history, and that we have enjoyed a long period of calm that at some point, sooner or later will be followed by changes unprecedented in human history.&#xA;The equilibrium we have enjoyed might be a kind of unstable equilibrium, and you might not need a very large perturbation to upset that equilibrium and send the system into a large climatic swing.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-08-11T16:57:39.597" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14854" PostTypeId="1" CreationDate="2018-08-11T17:55:46.283" Score="9" ViewCount="1099" Body="&lt;p&gt;I know that volcanoes and earthquakes occur on plate margins. But, do some of them also occur within plates? &lt;/p&gt;&#xA;" OwnerUserId="13565" LastEditorDisplayName="user20559" LastEditDate="2021-06-25T11:03:19.873" LastActivityDate="2021-09-22T12:13:04.453" Title="Why do some earthquakes and volcanoes occur within plates?" Tags="|geology|plate-tectonics|volcanology|earthquakes|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14855" PostTypeId="2" ParentId="14854" CreationDate="2018-08-11T19:20:55.263" Score="13" Body="&lt;p&gt;Crustal plates are not homogeneous, uniformly continuous rock masses with uniform stresses. They are a mixture of rock types with variable stresses and stress concentrations. They are also discontinuous.&lt;/p&gt;&#xA;&lt;p&gt;There are &lt;a href=&quot;https://en.wikipedia.org/wiki/Fault_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;fault&lt;/a&gt; zones within plates. Some faults are active &amp;amp; others inactive.  When movement occurs along an active fault, usually due to in-plate localized stresses, an in-plate earthquake will occur.&lt;/p&gt;&#xA;&lt;p&gt;Concerning in-plate volcanoes. These are due to geological &lt;a href=&quot;https://en.wikipedia.org/wiki/Hotspot_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;hotspots&lt;/a&gt;. These are,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;thought to be fed by underlying mantle that is anomalously hot compared with the surrounding mantle.[citation needed] Their position on the Earth's surface is independent of tectonic plate boundaries. There are two hypotheses that attempt to explain their origins. One suggests that hotspots are due to mantle plumes that rise as thermal diapirs from the core–mantle boundary. The other hypothesis is that lithospheric extension permits the passive rising of melt from shallow depths.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;Edit 22 September 2021&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Following a &lt;a href=&quot;https://www.abc.net.au/news/science/2021-09-22/earthquakes-in-australia-pavlova-demonstrates-how/100429578&quot; rel=&quot;nofollow noreferrer&quot;&gt;5.8 magnitude earthquake in southeastern Australia&lt;/a&gt; this description from a seismologist from &lt;a href=&quot;https://earthquakes.ga.gov.au/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geoscience Australia&lt;/a&gt; is a good example of how intraplate earthquakes occur.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;Imagine if you will, that a tectonic plate is analogous to a &lt;a href=&quot;https://en.wikipedia.org/wiki/Pavlova_(cake)&quot; rel=&quot;nofollow noreferrer&quot;&gt;pavlova&lt;/a&gt; — with a thin brittle crust lying above a ductile, but mostly solid meringue mantle,&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oHPnf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oHPnf.jpg&quot; alt=&quot;Pavlova&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;The Australian continent would sit in the middle of our pavlova.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;If you put your hands on the edge of the pavlova and start to squeeze, the crust around your hands will be the first to break, like those earthquakes at the boundaries of tectonic plates.&lt;/p&gt;&#xA;&lt;p&gt;But if you continue to squeeze, eventually strain builds up in the centre of the crust, and cracks will begin to appear.&lt;/p&gt;&#xA;&lt;p&gt;This is similar to how we get earthquakes in Australia.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;The same forces that drive earthquakes on tectonic plate boundaries are at play — they just take a lot longer to manifest in the middle of our pavlova,&lt;/p&gt;&#xA;&lt;p&gt;Australia is actually rocked by an earthquake about once per day, but the more damaging quakes — above magnitude-5 — are only typically seen about twice a year.&lt;/p&gt;&#xA;&lt;p&gt;But Dr Allen says it's extremely unlikely Australia would ever experience a magnitude-8 or 9 earthquake.&lt;/p&gt;&#xA;&lt;p&gt;That's because the forces necessary only occur at the plate boundaries, where plates can lock together and break apart with tremendous force.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;We don't have faults that are large enough or active enough to have these really big earthquakes we see on the plate boundaries,&amp;quot; Dr Allen says.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;In general, the rates of earthquakes we see here in Australia and in other stable tectonic regions are roughly about a hundred times less than that of areas on plate boundaries.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-09-22T12:13:04.453" LastActivityDate="2021-09-22T12:13:04.453" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14864" PostTypeId="1" AcceptedAnswerId="14866" CreationDate="2018-08-13T11:42:03.707" Score="5" ViewCount="603" Body="&lt;p&gt;I live near this ophiolite (Sasso di San Zanobi, Firenzuola) and they used to say it is a meteorite.&#xA;There is no evidence of a crater but let's pretend it is the remain of a meteorite: how big would the original meteorite have been?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/diVZA.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/diVZA.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7545" LastEditorUserId="11908" LastEditDate="2018-08-13T21:56:26.873" LastActivityDate="2018-08-13T21:56:26.873" Title="Is it possible to estimate the size of a meteorite from its remains?" Tags="|meteorite|igneous|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14866" PostTypeId="2" ParentId="14864" CreationDate="2018-08-13T16:16:38.040" Score="6" Body="&lt;p&gt;Meteors enter the atmosphere at speeds ranging from &lt;a href=&quot;https://www.amsmeteors.org/meteor-showers/meteor-faq/&quot; rel=&quot;nofollow noreferrer&quot;&gt;11 km/sec, to 72 km/sec&lt;/a&gt;. Those speeds are so large that if a meteorite were to hit the surface at that speed, the energy released would be more then enough to to vaporize the meteorite on impact, therefore leaving nothing of the original impacting body. However, during their fall, meteorites slow down due to the friction with the atmosphere. The friction is proportional to the square of the meteorite radius (its cross-section), but the mass is proportional to the cube of the radius (its volume). This means that the larger the meteorite the less it slows down and the faster it hits the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Past a given size, the atmosphere doesn't provide enough breaking power. Therefore, all meteorites larger than that limit vaporize during the impact. To have a sense of how big is that size limit you can simply have a look of the larger meteorite on Earth: the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hoba_meteorite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hoba meteorite&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dEmOb.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dEmOb.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(image taken from &lt;a href=&quot;https://www.tripadvisor.ca/Attraction_Review-g1137965-d3609771-Reviews-Hoba_Meteorite-Grootfontein_Otjozondjupa_Region.html#photos;aggregationId=101&amp;amp;albumid=101&amp;amp;filter=7&amp;amp;ff=292121881&quot; rel=&quot;nofollow noreferrer&quot;&gt;TripAdvisor and submitted by user huys25&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, what your picture shows is not a meteorite (there would be also other reasons beside the size to say so), nor the remains of one. The remains of large meteorites often reduce to small fragments that broke from the main body before impact, or &lt;a href=&quot;https://en.wikipedia.org/wiki/Impactite&quot; rel=&quot;nofollow noreferrer&quot;&gt;impactites&lt;/a&gt;. Impactites are small pieces of rock that might contain meteorite materials but are not unaltered pieces of it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Said that, once a meteorite is found the calculation of the original size considers the final size, the speed and angle of impact (computed from crater geometry) and the meteorite composition among other parameters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are many online calculators that allow you to have a rough estimate of the size of a crater that a meteorite like that would leave. For example the &lt;a href=&quot;http://www.convertalot.com/asteroid_impact_calculator.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Convertalot Asteroid Impact Calculator&lt;/a&gt;. From the picture it looks like porous rock, so plugging in a density of 1.5 g/cm$^3$ and impact angle of 45°, a fairly low speed of 20 m/s, and a diameter of 20 m, it would have produced an impact crater 177 meters in diameter and 44 meters deep. Definitely a landscape feature difficult to miss.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, from the shape of what you show in the picture, I don't see how it can be associated to a meteorite, as it doesn't look like one at all. In that line, it could resemble the central peak of an impact crater. Like the one visible at the center of &lt;a href=&quot;https://en.wikipedia.org/wiki/Tycho_(lunar_crater)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tycho crater&lt;/a&gt; on the Moon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/thYrv.png?s=300&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/thYrv.png?s=300&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;https://en.wikipedia.org/wiki/Tycho_(lunar_crater)#/media/File:Tycho_LRO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image source&lt;/a&gt;: Wikipedia - Tycho crater on the Moon: mosaic of images, made by Lunar Reconnaissance Orbiter. Width of the image is 120 km.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, if the central peak were that well preserved you would expect the rim of the crater to be well preserved too, and from what you say, that doesn't seem to be the case.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-08-13T18:02:01.737" LastActivityDate="2018-08-13T18:02:01.737" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14868" PostTypeId="1" AcceptedAnswerId="14873" CreationDate="2018-08-14T05:43:08.633" Score="11" ViewCount="461" Body="&lt;p&gt;While rivers often form a delta when they flow into a lake, the outflow of a lake is usually a single stream.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there lakes where the water flows off in multiple channels that merge into a single stream? If so, why does this happen, and what is it called?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/8p28d.png&quot; width=&quot;325&quot; height=&quot;350&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="13630" LastEditorUserId="11908" LastEditDate="2019-03-04T00:34:05.540" LastActivityDate="2019-03-04T00:34:05.540" Title="Lake outflow forming a &quot;reverse delta&quot;?" Tags="|hydrology|geography|rivers|lakes|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14869" PostTypeId="2" ParentId="14277" CreationDate="2018-08-14T13:10:04.047" Score="2" Body="&lt;p&gt;I think the answer to this question can be split into two parts. First, it is important to know which weather model you are using. Weather models use grids to predict the weather. The finer the grid, the better the topography (mountains) are represented by the weather model. To get a reasonable representation of the mountains that you mention, you would need a horizontal grid spacing of a few kilometers at most.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the second part of the answer, we will assume that the weather model you are looking at has a fine grid. The only effect that I can think of explaining the strong difference in the daily cycle between Seattle and the mountains, is the wind. At higher altitudes, radiative cooling cannot effectively bring down the temperatures since the air is continuously being mixed with air from the free atmosphere which has a much less pronounced daily cycle.&lt;/p&gt;&#xA;" OwnerUserId="13524" LastActivityDate="2018-08-14T13:10:04.047" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14873" PostTypeId="2" ParentId="14868" CreationDate="2018-08-14T17:19:30.530" Score="10" Body="&lt;p&gt;When the flow of water in a river accelerates, it can pick up more sediment from the river bed and transport it downstream. Alternatively, when the flow slows down, the transport capacity drops and the sediments suspended are deposited on the river bed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When a river goes into a lake, it transitions from the fast-flowing regime in the river to a very slow flow in the lake. Therefore, sediments are deposited as a result of the slowdown, forming a delta.&#xA;The inverse happen at the outlet of the lake, where the water accelerates. Therefore there sediments tend to be picked up and transported downstream, not allowing to the formation of a delta.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this only partially answer your question, because the terrain around lakes is very often flat, one would might expect to see plenty of examples of lakes being drained by multiple rivers. The answer to this is that multiple rivers in parallel are unstable: if one of the rivers becomes slightly larger, it will have more and faster flow. Therefore, it will increase its capacity to transport sediments, digging into its bed and growing even bigger. If it grows bigger, the sediment transport will increase further and the river will grow even more. This positive feedback leads to the grow of the largest outlet at the expense of the smaller ones, until you have only one river outlet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, it takes time for one outlet to monopolize the flow. And in very flat and changing terrain you can find lakes drained by a delta. One example of this is the proglacial lake of Kaskawulsh glacier in the Yukon Territory, Canada:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/naP0U.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/naP0U.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This lake is in a divide. And it is drained not by one, but by two deltas. Interestingly, the Slims river in the top of the picture has reversed its flow direction in historical times.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In &lt;a href=&quot;https://earthobservatory.nasa.gov/images/90116/river-piracy-in-the-yukon&quot; rel=&quot;noreferrer&quot;&gt;this NASA Earth Observatory article&lt;/a&gt;, you can find out more about this interesting river and some great images, plus comparisons of how the flow regime has changed in the past.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="6298" LastEditDate="2018-08-14T21:31:30.763" LastActivityDate="2018-08-14T21:31:30.763" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14875" PostTypeId="1" CreationDate="2018-08-14T23:16:05.947" Score="4" ViewCount="82" Body="&lt;p&gt;I'm looking to estimate the temperature at the end of a river reach of a few miles in length based on known (measured) temperature at the start of the reach plus weather information: historical data for model fitting and forecast data for forecasting.  I'd like this on a sub-day temporal timescale--let's say hourly. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From what I read, I presume that solar radiation is a key factor in determining the change in temperature from the start to the end of the reach, so I'm looking for ways to estimate the hourly solar radiation.  Then I can try a regression model of end-of-reach temperature vs. start-of-reach temperature and solar radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tend to work in R, so solutions that come as part of an R package would be nice, solutions easy to implement in R would probably be okay.  The R packages solaR and insol seem like potential candidates, but neither strike me as obvious choices yet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also found the 2005 &quot;Estimating hourly incoming solar radiation from limited meteorological data&quot; by spokas et al. (&lt;a href=&quot;https://naldc.nal.usda.gov/download/1910/PDF&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://naldc.nal.usda.gov/download/1910/PDF&lt;/a&gt;) and a USDA implementation in Java of the algorithm in SolarCalc (&lt;a href=&quot;https://www.ars.usda.gov/research/software/download/?softwareid=62&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ars.usda.gov/research/software/download/?softwareid=62&lt;/a&gt;).  Its data requirements--max and min daily air temperatures and rainfall--seem minimal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've looked at CRAN and GitHub, but the best thing I've found is the python pysolarcalc (&lt;a href=&quot;https://github.com/borevitzlab/pysolarcalc/tree/master/docs/src&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://github.com/borevitzlab/pysolarcalc/tree/master/docs/src&lt;/a&gt;).  I've skimmed the titles and summaries of many of the 160 questions here on solar radiation, too, but I haven't seen an answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone know of an implemntation of this algorithm in R?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone have a better solution to suggest?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bill&lt;/p&gt;&#xA;" OwnerUserId="13638" LastActivityDate="2018-08-14T23:16:05.947" Title="Hourly solar radiation estimates on a horizontal plane, preferably in R" Tags="|software|insolation|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14877" PostTypeId="1" AcceptedAnswerId="14888" CreationDate="2018-08-14T21:34:55.203" Score="3" ViewCount="2125" Body="&lt;p&gt;If say the Tsar Bomba had been detonated directly over one of the Earth’s magnetic poles at ground level, would the nuclear electromagnetic pulse generated from that blast have had any momentary effect on the strength of Earth’s magnetic field?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a nuclear EMP cannot disrupt/weaken the Earth’s magnetic field, would it still be powerful enough to momentarily energize the Earth magnetic field and would this powerful electromagnetic discharge fry any sensitive electronics devices around the Earth and/or satellites in low Earth orbit?&lt;/p&gt;&#xA;" OwnerUserId="23275" OwnerDisplayName="user15618" LastActivityDate="2018-08-16T19:38:15.437" Title="Would a nuclear explosion over one of the Earth’s magnetic poles momentarily disrupt/weaken the Earth’s magnetic field?" Tags="|planetary-science|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14879" PostTypeId="1" CreationDate="2018-08-15T17:21:43.673" Score="2" ViewCount="209" Body="&lt;p&gt;EDIT: My goal with this question was to better understand the impact of cooling systems on local urban environments, but its been pointed out I am asking the incorrect questions for the answer's Im looking for. So this can be disregarded, but I'm not deleting as deleting questions seems to be frowned upon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am exploring some ideas regarding the impact of urbanization on the climate and our environment. My basic thought process is that the vast majority of homes and work places have some form of air conditioning(I understand many parts of the world dont, but from estimates I saw the global average is still quite high). And as I understand it air conditioning functions to displace heat(and slight heat generation from the energy usage). Like putting a brick in a bucket causes the water level to rise so too does the outside heat level rise when the heat from inside buildings is displaced.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I am looking to find out is if there is a way to determine what percentage of the planet's land surface is covered by buildings occupied by humans to determine what percentage of the world is displacing heat from the inside of those buildings(and the area that space occupies) to outside(all the other area)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand not every building has air conditioning and will not being using that figure to make a determination(as my previous post had people suggesting). I am simply looking for a good place to start before adding control variables. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone have any resources to find out where one might come by these figures? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally if someone has a possibly better method to find out the information I'm looking for I would love suggestions.&lt;/p&gt;&#xA;" OwnerUserId="13645" LastEditorUserId="13645" LastEditDate="2018-08-17T18:14:36.197" LastActivityDate="2018-08-17T18:14:36.197" Title="Are there resources for determining what percentage of the earth's surface is occupied by air conditioned spaces?" Tags="|climate|data-analysis|" AnswerCount="1" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="14880" PostTypeId="1" CreationDate="2018-08-15T21:02:20.540" Score="4" ViewCount="497" Body="&lt;p&gt;The lowest atmospheric pressure in a tropical cyclone is generally located in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Eye_(cyclone)&quot; rel=&quot;nofollow noreferrer&quot;&gt;eye&lt;/a&gt; at the center of the cyclone; however, the air in the eye is &lt;em&gt;descending&lt;/em&gt;, while the air in the surrounding portions of the cyclone is strongly &lt;em&gt;ascending&lt;/em&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JDavq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JDavq.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Image by Kelvinsong at &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Hurricane-en.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikimedia Commons&lt;/a&gt;.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How, then, is the pressure in the eye, where the air is sinking, &lt;em&gt;lower&lt;/em&gt; than that in the eyewall, where the air is rising?&lt;/p&gt;&#xA;" OwnerUserId="12549" LastEditorUserId="10681" LastEditDate="2018-08-17T12:42:43.357" LastActivityDate="2018-08-17T12:42:43.357" Title="Why is the atmospheric pressure in a tropical cyclone lowest in the eye, even though it contains sinking air?" Tags="|meteorology|tropical-cyclone|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="14881" PostTypeId="1" CreationDate="2018-08-16T00:09:25.410" Score="4" ViewCount="96" Body="&lt;p&gt;I have really two questions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1) what evidence is there in favour that the majority of Earth's water formed with the planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) what evidence is there that the majority of water did not form with the Earth.&lt;/p&gt;&#xA;" OwnerUserId="13647" LastEditorUserId="13647" LastEditDate="2018-08-24T11:22:44.380" LastActivityDate="2018-08-24T11:22:44.380" Title="Endogenous Theories For the Origin of Earth's Water (Dry/Wet Accretion?)" Tags="|water|planetary-formation|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14883" PostTypeId="2" ParentId="14879" CreationDate="2018-08-16T09:02:30.397" Score="2" Body="&lt;p&gt;I would dispute the idea that the &quot;vast majority&quot; of the world's buildings have air con; in fact, considering that a large proportion of the world's buildings are either (a) in hitherto cool places; or (b) in undeveloped places, I would imagine that it's probably a minority. But I don't have figures on this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main part of the question, though, is about the proportion of the earth's surface that is built on. That could be approached as a GIS exercise, and would be reasonably easy to do in places like the UK that have freely-available maps that show all buildings... and very much harder to do in parts of the world that don't.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://sedac.ciesin.columbia.edu/data/set/grump-v1-urban-extents&quot; rel=&quot;nofollow noreferrer&quot;&gt;This study&lt;/a&gt; made an estimate (from various data sources, including nighttime lighting) that about 3% of the Earth's land area is &quot;urban&quot;. That certainly doesn't include all buildings, but it also includes urban spaces that are not buildings, so it may serve as a useful first approximation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Depending on your objective, you might find it more useful to stop thinking specifically about air conditioning and instead ask about heat produced by buildings. All buildings produce heat, whether this is from heating, cooling, or other energy use. As a proxy for this net heat production you could simply look at the buildings' energy consumption.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2018-08-16T09:02:30.397" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14884" PostTypeId="2" ParentId="14877" CreationDate="2018-08-16T09:11:36.837" Score="5" Body="&lt;p&gt;There are a few different questions lurking here.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;No, it would not have any lasting effect on the Earth's magnetic field. That field is not generated at the surface, at the poles or otherwise.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Yes, it would produce an electromagnetic pulse, and that could be harmful to unshielded electronics in at least a line-of-sight sense.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Yes, this EMP would definitely cause localized magnetic effects for a very brief moment, which one could argue constitute a change in the natural magnetic field.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;I'm not sure whether there's any reason to think that the earth's magnetic field could help these effects to propagate beyond line of sight - which I think is what you're really asking. Perhaps a physicist could chime in...&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2018-08-16T19:38:15.437" LastActivityDate="2018-08-16T19:38:15.437" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14885" PostTypeId="2" ParentId="14597" CreationDate="2018-08-16T11:56:31.057" Score="0" Body="&lt;p&gt;The best solution I've found so far is to use Dark Sky's &lt;a href=&quot;https://darksky.net/dev/docs#time-machine-request%20API&quot; rel=&quot;nofollow noreferrer&quot;&gt;Time Machine&lt;/a&gt;. You can request the forecast for any number of days in the future, and beyond 10 days, the API simply returns historical data.&lt;/p&gt;&#xA;" OwnerUserId="13344" LastEditorUserId="13344" LastEditDate="2022-01-25T20:12:47.977" LastActivityDate="2022-01-25T20:12:47.977" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14886" PostTypeId="1" CreationDate="2018-08-16T14:22:49.677" Score="0" ViewCount="305" Body="&lt;p&gt;Related to this post: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7446/if-the-earth-were-a-smooth-spheroid-how-deep-would-the-ocean-be/7448#7448?newreg=42cc48867c774b68b15ebfcc653e31c8&quot;&gt;If the Earth were a smooth spheroid, how deep would the ocean be?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13652" LastActivityDate="2018-08-17T14:22:40.150" Title="If the earth were completely smooth and covered in water, what would occur with ocean waves?" Tags="|geology|ocean|world-building|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14888" PostTypeId="2" ParentId="14877" CreationDate="2018-08-16T16:03:54.250" Score="3" Body="&lt;p&gt;“to momentarily energize the Earth magnetic field”... hm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A nuclear explosion has two effects that one could connect with the subject of magnetic fields:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The EMP. This is very quick. Like any EM signal, it just follows the wave solution of the Maxwell equations (which are in air very linear, so the amplitude isn't really important), meaning it spreads out at the speed of light, well ahead of the pressure and ionisation effects. The lower-frequency parts will partly be reflected at the ionosphere, you may get some whistler-mode dispesion. This isn't really special to the nuclear bomb (it also happens with lightning transients), and it's completely independent of the Earth's static magnetic field. Yes, the EMP itself also has a magnetic component, but this is short-lived and actually not that strong; only because it's a dynamic field with a strong &lt;em&gt;electrical&lt;/em&gt; component does the pulse destroy electronics. (Magnetically, it's much weaker that the disturbances solar flares can cause on Earth.)&lt;/li&gt;&#xA;&lt;li&gt;The ionisation. A nuclear bomb turns a significant volume of air into plasma, both through the heating and through radiation. In plasma, you don't have separate dynamics for the gas and EM fields anymore, but both are linked together in magnetohydrodynamics. However, not much air is heated so much&lt;sup&gt;†&lt;/sup&gt; that, at the high densities you have a surface level, you'd actually have electrical conductivity for a long time – recombination removes most of the ions quickly. Only a high voltage would be able to sustain a current (and thus effect a magnetic field), which again is just what happens in a lightning, but that too is short-lived.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;So, no, I don't think there's much interesting to be said here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It might also be worth noting that the Tsar Bomba actually did explode at quite high latitude, 74°N. At that time the magnetic pole itself was only at 75°N (albeit on the western hemisphere, so the explosion wasn't actually at very high &lt;em&gt;magnetic&lt;/em&gt; latitude).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;hr&gt;&#xA;&lt;sup&gt;†&lt;/sup&gt;&lt;sub&gt;The hard radiation which does most of the initial heating in the fireball does so precisely because it interacts strongly with air, but that also means it doesn't reach very far. The components that reach through air can immediately burn surfaces miles away, but they don't much heat &lt;em&gt;the air&lt;/em&gt; they pass through. Only the mechanical (i.e. acoustic) shock wave causes a heating again, but this is transient.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="12095" LastActivityDate="2018-08-16T16:03:54.250" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14889" PostTypeId="2" ParentId="10307" CreationDate="2018-08-16T17:04:33.323" Score="1" Body="&lt;p&gt;I think there is good evidence that air pressure was 3-5 times higher during hothouse periods like the Mesozoic Era. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It solves how&#xA;1 Pterosaurs could fly&#xA;2 Sauropods could grow up to 80 metric tons&#xA;3 Why arthropods were much larger&#xA;4 The climate was so warm and wet, even at the poles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Someday I plan on getting a team together to investigate this further; not that the atmosphere was denser at the surface, but how it would be possible.  The obvious answer will be found in the correlation between ocean chemistry cycles and hothouse/icehouse climate cycles.  The correlation suggests that the oceans were significantly warmed via geothermal heat flux but more importantly hydrothermal pumping, causing increased degassing and evaporation, and thus a thicker atmosphere.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fact that marine chemistry and the major climate cycles correlate very well and marine chemistry is controlled by variable rates in sea floor production suggests some link between the two and it is sad to me that no one has investigated this link beyond invoking that CO2 is the overarching climate control knob, which all evidence suggests to be erroneous. It's basic physics - gravitational potential energy and kinetic theory of gases - the heavier the atmosphere over your head the warmer the surface will be. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://ftp.earthbyte.org/Resources/Pdf/Muller_etal_2013_Seawater_chemistry_driven_by_Supercontinent_assembly_breakup_dispersal_Geology.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://ftp.earthbyte.org/Resources/Pdf/Muller_etal_2013_Seawater_chemistry_driven_by_Supercontinent_assembly_breakup_dispersal_Geology.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://s3.amazonaws.com/academia.edu.documents/3468640/Veizer_Nature_2001.pdf?AWSAccessKeyId=AKIAIWOWYYGZ2Y53UL3A&amp;amp;Expires=1534442228&amp;amp;Signature=3Pxz67vBnWWnBbh%2BUzIp%2BwnewP4%3D&amp;amp;response-content-disposition=inline%3B%20filename%3DEvidence_for_decoupling_of_atmospheric_C.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://s3.amazonaws.com/academia.edu.documents/3468640/Veizer_Nature_2001.pdf?AWSAccessKeyId=AKIAIWOWYYGZ2Y53UL3A&amp;amp;Expires=1534442228&amp;amp;Signature=3Pxz67vBnWWnBbh%2BUzIp%2BwnewP4%3D&amp;amp;response-content-disposition=inline%3B%20filename%3DEvidence_for_decoupling_of_atmospheric_C.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another good comparison would be crocodilia since they are still extant today.  They were much larger in the mesozoic (up to 8 tonnes!) but food availability is not limiting the size of these creatures today.  The size limitation is due physical limitations as body mass increases. In a denser atmosphere you explain why these physical limitations are at a much larger body size.&lt;/p&gt;&#xA;" OwnerUserId="13653" LastEditorUserId="13653" LastEditDate="2018-08-16T17:33:38.990" LastActivityDate="2018-08-16T17:33:38.990" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="14890" PostTypeId="2" ParentId="10307" CreationDate="2018-08-16T18:57:40.257" Score="10" Body="&lt;p&gt;Yes, there is.&#xA;But the data is still very sparse and errors are large.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Past atmospherics pressures have been estimated by at least three different methods:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;strong&gt;Isotopic composition of fluid inclusions trapped hydrothermal quartz&lt;/strong&gt; ( &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0012821X06008600&quot; rel=&quot;noreferrer&quot;&gt;Nishizawa ey al 2007&lt;/a&gt;; &lt;a href=&quot;https://www.nature.com/articles/ngeo692&quot; rel=&quot;noreferrer&quot;&gt;Goldblatt et al 2009&lt;/a&gt;; &lt;a href=&quot;http://science.sciencemag.org/content/342/6154/101&quot; rel=&quot;noreferrer&quot;&gt;Marty et al, 2013&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Y5taL.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Y5taL.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image from Fig. 2 of &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0012821X06008600&quot; rel=&quot;noreferrer&quot;&gt;Nishizawa et al 2007&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;&lt;strong&gt;Size distribution of gas bubbles in basaltic lava flows&lt;/strong&gt; (&lt;a href=&quot;https://www.nature.com/articles/ngeo2713&quot; rel=&quot;noreferrer&quot;&gt;Som et al 2016&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JgLHI.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JgLHI.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Figure 3c of &lt;a href=&quot;https://www.nature.com/articles/ngeo2713&quot; rel=&quot;noreferrer&quot;&gt;Som et al (2016)&lt;/a&gt;: Beasley River geologic context and flow detail (scale bar, 1 cm)&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;&lt;strong&gt;Size distribution of fossilised raindrop imprints&lt;/strong&gt; (&lt;a href=&quot;https://www.nature.com/articles/nature10890&quot; rel=&quot;noreferrer&quot;&gt;Som et al, 2012&lt;/a&gt;; &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0012821X14007936&quot; rel=&quot;noreferrer&quot;&gt;Kavanagh &amp;amp; Goldblat, 2015&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/S2r6P.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/S2r6P.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Figure 1 of &lt;a href=&quot;https://www.nature.com/articles/nature10890&quot; rel=&quot;noreferrer&quot;&gt;Som et al (2012)&lt;/a&gt; The 2.7-billion-year-old Ventersdorp Supergroup raindrop imprints lithified in tuff at Omdraaivlei, South Africa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each study is based on samples that capture the conditions at a fairly specific point in time. Therefore, different results not necessarily contradict each other, but offer a sense of how variable has been the atmospheric pressure over geological time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The size distribution of fossilised raindrop imprints might have a large range of error due to the many factors that influence drop size beside atmospheric pressure. However, some studies suggest that the &lt;a href=&quot;https://en.wikipedia.org/wiki/Archean&quot; rel=&quot;noreferrer&quot;&gt;Archean&lt;/a&gt; (4 to 2.5 billion years ago) atmosphere was almost ten times denser than it is today (&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0012821X14007936&quot; rel=&quot;noreferrer&quot;&gt;Kavanagh &amp;amp; Goldblat, 2015&lt;/a&gt;). That figure is based on fossilized raindrop imprints dated about 2.7 billion year ago, that is after the evolution of photosynthesis, but still in its early stages, when &lt;a href=&quot;https://en.wikipedia.org/wiki/Geological_history_of_oxygen&quot; rel=&quot;noreferrer&quot;&gt;most oxygen was absorbed by the oceans&lt;/a&gt; and there was very little of it in the atmosphere.&#xA;On the other hand, studies based in isotopic composition of fluid inclusions and bubbles in basaltic lava have found that the atmosphere was less dense than it is today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These studies are of great interest, as a denser atmosphere even if poor in greenhouse gasses can produce warmer surface condition, helping to resolve the &lt;a href=&quot;https://en.wikipedia.org/wiki/Faint_young_Sun_paradox&quot; rel=&quot;noreferrer&quot;&gt;faint young Sun paradox&lt;/a&gt;. In a nutshell, this paradox refers to how could liquid water exist on Earth in the past when the sun was much fainter than it is today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is important to note that the additional temperature in a thick atmosphere doesn't come from adiabatic warming as some people have suggested here. A good treatment of the phenomena is presented by Chemke et al (2016) in the paper &quot;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1002/2016GL071279&quot; rel=&quot;noreferrer&quot;&gt;The thermodynamic effect of atmospheric mass on early Earth's temperature&lt;/a&gt;&quot;, there they say:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We find that higher atmospheric mass tends to increase the&#xA;  near-surface temperature mostly due to an increase in the heat&#xA;  capacity of the atmosphere, which decreases the net radiative cooling&#xA;  effect in the lower layers of the atmosphere. Additionally, the&#xA;  vertical advection of heat by eddies decreases with increasing&#xA;  atmospheric mass, resulting in further near-surface warming.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-08-16T20:07:56.063" LastActivityDate="2018-08-16T20:07:56.063" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14891" PostTypeId="2" ParentId="13654" CreationDate="2018-08-17T08:45:25.757" Score="-1" Body="&lt;p&gt;1)You have to consider the source of water for each location. Groundwater, for example, is a fairly abundant but non-renewable water source in some locations. It can take a centuries to replenish.&#xA;2)River water fed by mountain glaciers depends on the size of the glacier, as the glaciers shrink, meltwater decreases.&#xA;3)Regions that depend on rainwater or snowmelt can experience water shortages when there's a low-snow winter or drought.&#xA;Even is there is sufficient water available it is often of insufficient quality for the purpose you want it for&#xA;We often don't drink straight out of rivers&#xA;We don't irrigate with salt water&#xA;This adds to the experience of shortage.&lt;/p&gt;&#xA;" OwnerUserId="13656" LastActivityDate="2018-08-17T08:45:25.757" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14892" PostTypeId="2" ParentId="14886" CreationDate="2018-08-17T14:22:40.150" Score="3" Body="&lt;p&gt;Consider ocean waves in the middle of a large ocean. They are being powered by the wind, but also lose energy due to viscosity, breaking and similar factors. Since the timescale for a wave changing is much smaller than the timescale of it crossing an ocean, for all practical purposes they already experience an infinite ocean. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A featureless ocean world would presumably have many somewhat constant wind systems that could add a lot of energy to wave motion, but with an absence of shores to break on these energetic waves will just keep on going with an amplitude where the average energy gained and lost are equal. Since even a powerful tsunami is nearly invisible in deep water, the ocean world would look relatively calm with merely a lot of ocean swell.&lt;/p&gt;&#xA;" OwnerUserId="12421" LastActivityDate="2018-08-17T14:22:40.150" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14893" PostTypeId="1" AcceptedAnswerId="14894" CreationDate="2018-08-17T17:20:36.453" Score="8" ViewCount="424" Body="&lt;p&gt;In most photos from space, the atmosphere gradually fades away from pretty bright blue to essentially black, as you move away from the Earth surface, such as can be seen in this photo of the Earth from the ISS (also showing some noctilucent clouds):&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://www.nasa.gov/sites/default/files/styles/full_width_feature/public/thumbnails/image/27420333805_6fd1876a46_o.jpg&quot; alt=&quot;NASA photo of Earth atmosphere&quot; /&gt;&lt;br /&gt;&#xA;NASA photo of Earth atmosphere.  Source: &lt;a href=&quot;https://www.nasa.gov/image-feature/space-station-view-of-noctilucent-clouds/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Or by night (again with noctilucent clouds):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aD4n6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aD4n6.jpg&quot; alt=&quot;NASA photo of Earth atmosphere by night&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;Earth atmosphere by night.  Source: &lt;a href=&quot;https://web.archive.org/web/20210125033707/https://spaceflight.nasa.gov/gallery/images/station/crew-17/html/iss017e011632.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Yet in photos with an exposure long enough for stars and airglow to be clearly visible, the opposite appears to be the case:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://apod.nasa.gov/apod/image/1511/iss044e045565a.jpg&quot; alt=&quot;ISS photo of Earth and milky way&quot; /&gt;&lt;br /&gt;&#xA;NASA photo of Earth atmosphere and milky way.  Source: &lt;a href=&quot;https://apod.nasa.gov/apod/ap151107.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;In the third photo, the Earth is rather dark.  Moving away from the Earth, the sky closest to the Earth is colourful, but faint enough for stars to be visible through it.  Then the atmosphere appears to get &lt;em&gt;brighter&lt;/em&gt; as you move further up, until it becomes abruptly black after a sharp edge.  Higher up still we can see a faint but clearly visible band of red airglow.  It's not aurora — aurora is higher up than airglow, and not so constant.&lt;/p&gt;&#xA;&lt;p&gt;Another example, but with different colours (that could be a side-effect of exposure or editing):&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/4/4e/ISS-42_Starry_Night_%282%29.jpg/1024px-ISS-42_Starry_Night_%282%29.jpg&quot; alt=&quot;ESA starry night&quot; /&gt;&lt;br /&gt;&#xA;ESA starry night.  Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:ISS-42_Starry_Night_%282%29.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;ESA via Wikimedia Commons&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="2958" LastEditDate="2023-01-10T06:46:00.540" LastActivityDate="2023-01-10T06:46:00.540" Title="Why is the upper atmosphere brighter than the lower atmosphere in some photos from space?" Tags="|atmosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14894" PostTypeId="2" ParentId="14893" CreationDate="2018-08-17T19:19:00.000" Score="9" Body="&lt;p&gt;The glow observed in those pictures in the upper layers of the atmosphere is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Airglow&quot; rel=&quot;noreferrer&quot;&gt;airglow&lt;/a&gt; from OH molecules. OH emission peaks between 75 and 105 km of elevation (&lt;a href=&quot;https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19660017562.pdf&quot; rel=&quot;noreferrer&quot;&gt;Blamont and Reed, 1967&lt;/a&gt;) with intensities peaking at different wavelengths, the most prominent peaks in the visible spectrum are 557nm (Green), and multiple other peaks between 620 and 750 nm (red)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In 1965 the OGO-II satellite was launched with the propose to measure airglow, the following image show a typical altitude vs intensity profile:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YK6vE.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YK6vE.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19660017562.pdf&quot; rel=&quot;noreferrer&quot;&gt;Blamont and Reed, (1967)&lt;/a&gt;. The peak around 100 km is mostly due to OH airglow and the broader peak around 250 km is mostly due to atomic oxigen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding the color observed in the pictures, while it is difficult to trust them due to photo editing, they are consisten with OH airglow, in the greens, yellows and reds. This is the airglow spectrum from &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JA073i001p00426&quot; rel=&quot;noreferrer&quot;&gt;Broadfoot  and Kendall (1968)&lt;/a&gt;, where I've highlighted in yellow the most important emission bands of OH in the visible range:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IYhzo.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IYhzo.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get a sense of the color associated to each band here is a approximate scale (remember 1 nm = 10 Å)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Bbvt8.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Bbvt8.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;https://en.wikipedia.org/wiki/Visible_spectrum#/media/File:Linear_visible_spectrum.svg&quot; rel=&quot;noreferrer&quot;&gt;wikipedia&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fading yellow glow that goes below the brightest band can be explained as the OH glow at the same altitude band (75-105 km) but originating from the part of the atmosphere that is closer (or further) to the spacecraft from which the picture was taken. As that altitude band is a shell around the Earth and not a ring. For the same reason the peak intensity in the picture is likely a bit lower than altitude of the peak in emissions.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-08-17T20:07:36.483" LastActivityDate="2018-08-17T20:07:36.483" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14896" PostTypeId="2" ParentId="14654" CreationDate="2018-08-17T22:34:30.297" Score="2" Body="&lt;p&gt;While the best way to test for hydrocarbons in drinking water is to get a specialized test kit like the one you posted in your edit or to send a water sample to a lab, there might be a cheaper DIY way to do it.  I haven't tested it but I think it is worth a try:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Detecting hydrocarbons is exactly what is typically done when detecting leaks due to broken head gaskets in combustion engines. A broken seal in the combustion chamber of the engine can push some vaporized gasoline into the coolant. Therefore, the standard way to find such leaks is to test for hydrocarbons in the fumes that come out of the coolant when opening the radiator cap. To do so they sell very cheap tests that allow you to suck up those fumes and get them to mix with a chemical reactant which changes color if there are hydrocarbons present.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is an example of the test:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/g02wB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/g02wB.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And in &lt;a href=&quot;https://www.youtube.com/watch?v=CHp5E7XnbXo&quot; rel=&quot;nofollow noreferrer&quot;&gt;this video&lt;/a&gt;, you can see how it works.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you Google &quot;head gasket leak test&quot;, &quot;combustion leak kit&quot;, or &quot;block test&quot; you will find tons of options, and you will very likely also find it also in local shops.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the concentrations in your tap water would be much lower than in the design application of these tests. Therefore, the detection that takes minutes in a car might take hours in your tap water. I envision that you may be able to leave the tap open with one of these tests continuously sucking the fumes coming out of the water (if any). To do so, you can put a tube from your vacuum cleaner to one end of the test device (adjusting the size and leakage of the tube so it provide a reasonable amount of suction), so it will get the fumes to bubble through the liquid as long as you want.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a very rough hand-drown illustration of the setup I'm describing:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gJYWv.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gJYWv.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you get it to change color, then you will then need to figure out the concentration. That would require some additional tests, perhaps doing the same with water with a known amount of hydrocarbons added. Alternatively, you can use that evidence to decide whether to go forward with a professional testing or not.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-08-18T16:46:39.063" LastActivityDate="2018-08-18T16:46:39.063" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="14899" PostTypeId="1" AcceptedAnswerId="14901" CreationDate="2018-08-18T15:25:24.700" Score="6" ViewCount="2077" Body="&lt;p&gt;While looking into the better indicator of how miserable it feels outside, either dew point or relative humidity, I came across this statement:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The optimum combination for human comfort is a dewpoint of about 60°F&#xA;  and a RH of between 50 and 70% (this would put the temperature at&#xA;  about 75°F).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://www.theweatherprediction.com/habyhints/190/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.theweatherprediction.com/habyhints/190/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This led me to this &lt;a href=&quot;http://andrew.rsmas.miami.edu/bmcnoldy/Humidity.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;calculator&lt;/a&gt; that will calculate the temperature given relative humidity and dew point - for example a dew point of 70°F and a relative humidity of 90% results in a temperature of 73.11°F.  The web site for this calculator says the values are based on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Clausius%E2%80%93Clapeyron_relation#Meteorology_and_climatology&quot; rel=&quot;nofollow noreferrer&quot;&gt;August-Roche-Magnus approximation&lt;/a&gt; and gives the following equation to calculate temperature:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$T =243.04 \Large \frac{\frac{17.625\ TD}{243.04+TD}-\ln\left(\frac{RH}{100}\right)}{17.625+\ln\left(\frac{RH}{100}\right)-&#xA;\frac{17.625\ TD}{243.04+TD}}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given the equation, I'm still having a hard time figuring out how the temperature is being calculated. Can somebody please explain how the temperature is being calculated in simple terms?&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastEditorUserId="15513" LastEditDate="2019-03-25T02:24:37.550" LastActivityDate="2019-03-25T14:20:14.677" Title="How can temperature be calculated given relative humidity and dew point?" Tags="|meteorology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14901" PostTypeId="2" ParentId="14899" CreationDate="2018-08-18T16:34:10.147" Score="8" Body="&lt;p&gt;To understand that formula, it's better to start from the more intuitive dependence of dew point with temperature and relative humidity, as illustrated by the following graph from &lt;a href=&quot;https://en.wikipedia.org/wiki/Dew_point&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/moAiT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/moAiT.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for any solvent with a solute, the higher the temperature of the solvent the more solute it can hold. That's why hot water can dissolve more sugar than cold water. Or, for a given quantity of sugar, hot water dissolves it faster than cold water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The figure above says basically the same: Hotter air dissolves more water. Condensation happens when the amount of water in the air is more that the amount the air can actually hold. The dew point is the temperature at which condensation appears. Therefore, for a given relative humidity, the hotter the air, the higher is the dew point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Dew_point&quot; rel=&quot;nofollow noreferrer&quot;&gt;Magnus&lt;/a&gt; approximation, the relationship is just a straight line, with a slope and constant changing for different values of the relative humidity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll assign letters to each constant for simplicity, so that&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$b=17.625$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$c=243.04$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With that, the dew point can be calculated as&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$TD= \large c \LARGE \frac{\ln\left(\frac{RH}{100}\right)+\frac{b T}{c+T}}{b-\ln\frac{RH}{100}-\frac{b T}{c+T}}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(see &lt;a href=&quot;https://en.wikipedia.org/wiki/Dew_point#Calculating_the_dew_point&quot; rel=&quot;nofollow noreferrer&quot;&gt;Calculating the dew point&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I won't do the algebra, but if you rearrange that formula so that &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; is written as function of &lt;span class=&quot;math-container&quot;&gt;$TD$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$RH$&lt;/span&gt;, you will go back to the formula you presented.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="15513" LastEditDate="2019-03-25T14:20:14.677" LastActivityDate="2019-03-25T14:20:14.677" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14903" PostTypeId="1" AcceptedAnswerId="14912" CreationDate="2018-08-19T04:34:12.770" Score="5" ViewCount="1650" Body="&lt;p&gt;I may sound completely stupid but this idea hit me when I saw termites ate a plastic bag packed with papers today in my house. What are the challenges we're likely to face if we decide to do this?&lt;/p&gt;&#xA;" OwnerUserId="13663" LastActivityDate="2021-02-07T17:57:34.653" Title="Why don't we feed the plastics to the termites?" Tags="|environmental-protection|plastic|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14904" PostTypeId="1" AcceptedAnswerId="14908" CreationDate="2018-08-19T09:56:47.167" Score="2" ViewCount="560" Body="&lt;p&gt;Are there interdisciplinary sciences which combine earth sciences (like geophysics, climatology, meteorology etc.) and computer science? or something like biotechnology which combine biology with several fields.&lt;/p&gt;&#xA;" OwnerUserId="11837" LastEditorUserId="11837" LastEditDate="2018-08-19T10:11:53.450" LastActivityDate="2018-08-19T18:49:15.347" Title="Interdisciplinary sciences which combine earth sciences with computer science" Tags="|meteorology|climatology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14905" PostTypeId="1" CreationDate="2018-08-19T10:42:35.187" Score="2" ViewCount="560" Body="&lt;p&gt;I just read this short article from Scientific American: &lt;a href=&quot;https://blogs.scientificamerican.com/observations/archaeologists-take-wrong-turn-find-world-s-oldest-stone-tools-update/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Archaeologists Take Wrong Turn, Find World's Oldest Stone Tools&lt;/a&gt; about Sonia Harmand's discoveries. The last sentence is:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Harmand says the newly discovered tools are different enough from the early Oldowan implements to warrant a new name: the Lomekwian.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Earlier the article says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The tools from Lomekwi 3 are quite large—larger than the stone tools from the site of Gona in Ethiopia that were previously the oldest on record and larger than the rocks that chimpanzees use to crack open nuts. According to Harmand, preliminary observations suggest that the Lomekwi toolmakers intentionally selected big, heavy blocks of very hard raw material from nearby sources even though smaller blocks were available. They used various knapping techniques to remove the sharp-edged flakes from the cores.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;How does the Lomekwi technique (ca. 3.3 mya) differ from &lt;a href=&quot;https://en.wikipedia.org/wiki/Oldowan&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oldowan&lt;/a&gt; (ca. 2.7 mya)? From Wikipedia:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;These early tools were simple, usually made with one or a few flakes chipped off with another stone.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Without any further details, the two techniques sound the same, and the size difference alone doesn't sound like enough to warrant a separate classification. What is so different about Lomekwi to not call it Oldowan?&lt;/p&gt;&#xA;" OwnerUserId="5417" LastActivityDate="2018-08-19T10:42:35.187" Title="Why are Lomekwian tools considered different from Oldowan tools?" Tags="|paleontology|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14907" PostTypeId="1" AcceptedAnswerId="15173" CreationDate="2018-08-19T16:43:32.273" Score="4" ViewCount="212" Body="&lt;p&gt;So I've been following the situation in &lt;a href=&quot;https://en.wikipedia.org/wiki/Lombok&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lombok, Indonesia&lt;/a&gt; from both online news and friends on the ground. One thing that I can't seem to figure out is why there are &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/map/#%7B%22autoUpdate%22%3A%5B%5D%2C%22basemap%22%3A%22grayscale%22%2C%22feed%22%3A%221534712794451%22%2C%22listFormat%22%3A%22default%22%2C%22mapposition%22%3A%5B%5B-9.663030792615071%2C114.64233398437499%5D%2C%5B-7.623886853120036%2C118.157958984375%5D%5D%2C%22overlays%22%3A%5B%22plates%22%5D%2C%22restrictListToMap%22%3A%5B%22restrictListToMap%22%5D%2C%22search%22%3A%7B%22id%22%3A%221534712794451%22%2C%22name%22%3A%22Search%20Results%22%2C%22isSearch%22%3Atrue%2C%22params%22%3A%7B%22starttime%22%3A%222018-07-01%2000%3A00%3A00%22%2C%22endtime%22%3A%222018-08-19%2023%3A59%3A59%22%2C%22maxlatitude%22%3A-7.994%2C%22minlatitude%22%3A-9.297%2C%22maxlongitude%22%3A117.081%2C%22minlongitude%22%3A115.719%2C%22minmagnitude%22%3A5%2C%22orderby%22%3A%22time%22%7D%7D%2C%22sort%22%3A%22newest%22%2C%22timezone%22%3A%22utc%22%2C%22viewModes%22%3A%5B%22list%22%2C%22map%22%5D%2C%22event%22%3Anull%7D&quot; rel=&quot;nofollow noreferrer&quot;&gt;so many earthquakes over an extended period of time&lt;/a&gt;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it common for there to be earthquakes for a whole month and of high magnitudes too in seismic zones?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have read that there can be aftershocks but I don't think that all these quakes can be characterized as aftershocks of the initial quake? These quakes seem to be independent quakes and not a continuation of aftershocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The major 3 have also been progressing from the south to the northwest to the northeast of the island as though it is following some pattern. So is this a sign that an underlying seismic development such as a major shift in tectonic plates or a new volcano formation will take place?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please explain it to me like I'm 5.&lt;/p&gt;&#xA;" OwnerUserId="13665" LastEditorUserId="725" LastEditDate="2018-09-01T14:02:52.263" LastActivityDate="2018-09-24T21:32:04.463" Title="Why do major earthquakes keep happening in Lombok recently?" Tags="|earthquakes|seismology|seismic-hazards|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14908" PostTypeId="2" ParentId="14904" CreationDate="2018-08-19T17:14:05.443" Score="5" Body="&lt;p&gt;Pretty much all Earth Sciences combine deeply with computer sciences. In many areas where the underlying physical phenomena are not well understood, machine learning is often used, and numerical models are a very common tool in pretty much all fields in Earth Sciences.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think some notable examples where Earth Science is working side by side with leading edge computer sciences are large scale numerical models. A large fraction of the work done by today's larger supercomputers is running atmospheric models for weather forecasting. Similar models are often run also for reanalysis of historic climate, long term climate evolution, oceanic currents, models of Earth's core and its magnetic field, mantle convection, and the list could go on and on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Inverse modelling and tomography are also areas were leading edge computer sciences are applied to Earth Science problems. Such as reconstructing the structure of earth interior from seismic tomography, inverting for the basal conditions of glaciers, or in a more applied field; electric, seismic and magnetic tomograhies to find minerals and oil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It terms of formally mixed fields, you can think of many, starting from my own field: &lt;a href=&quot;https://en.wikipedia.org/wiki/Geophysics&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geophysics&lt;/a&gt;, where physics is used to understand the Earth system. Although, many geophysicist work in &lt;a href=&quot;https://en.wikipedia.org/wiki/Planetary_science#Planetary_geology&quot; rel=&quot;nofollow noreferrer&quot;&gt;Planetary Sciences&lt;/a&gt;, where the same methods are applied to other bodies beside the Earth, of course they work shoulder to shoulder with astronomers and space scientists. And like that, there are many others, like &lt;a href=&quot;https://en.wikipedia.org/wiki/Geochemistry&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geochemistry&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Biogeochemistry&quot; rel=&quot;nofollow noreferrer&quot;&gt;Biogeochemistry&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Geomicrobiology&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geomicrobiology&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Biogeography&quot; rel=&quot;nofollow noreferrer&quot;&gt;Biogeography&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Chemical_oceanography&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chemical oceanography&lt;/a&gt;, and many others.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-08-19T18:49:15.347" LastActivityDate="2018-08-19T18:49:15.347" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14909" PostTypeId="2" ParentId="14641" CreationDate="2018-08-19T18:37:37.637" Score="5" Body="&lt;p&gt;Auroras typically happen pretty high. About a century ago, Norwegian scientist triangulated more than 12,000 auroras, and this is the distribution they found:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TNt29.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TNt29.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Figure 1 from &lt;a href=&quot;https://onlinelibrary.wiley.com/doi/pdf/10.1029/TE051i004p00501&quot; rel=&quot;noreferrer&quot;&gt;Störmer, 1946&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the fist problem will be to &quot;touch&quot; anything at an elevation of 100 km, where the atmospheric pressure is 0.00006% of the sea level pressure and 0.0002% of the pressure at the top of Mount Everest (pressures estimated using &lt;a href=&quot;http://www.calctool.org/CALC/phys/default/pres_at_alt&quot; rel=&quot;noreferrer&quot;&gt;CalcTool&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So let's imagine you use very thin space suit that stop your body from blowing up, and keep you alive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even in that case, the air is so thin that its heat capacity and conductivity would be extremely low. Therefore, no matter if the air is at -100°C or +300°C, you wouldn't feel it, and the temperature of your fingers would be dominated by the heat loss through radiation (i.e. your hot fingers would radiate infrared radiation and become very cold pretty soon).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Visually they are diffuse objects, so it will be as disappointing as &quot;touching&quot; a cloud. Where you never really feel you ever get to the &quot;edge&quot; of the cloud and touch it. You just feel that you become shrouded in an increasingly thick fog. That's is at least my experience climbing mountains that from below look like they have their top covered in thick clouds. On airplanes the experience is quite similar. So I think you will just not realize you are at the edge of an aurora and you will just see a subtle glow in the air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another important effect would be the radiation. You would get a big dose. I mention a bit of this in my answer to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/14838/why-are-pole-reversals-not-more-detrimental-to-life/14844#14844&quot;&gt;this&lt;/a&gt; question, however the formula there is not valid at 100 km. Because radiation increase exponentially the first 10-15 km as you go up, and then flattens (&lt;a href=&quot;https://cds.cern.ch/record/557167/files/p41.pdf&quot; rel=&quot;noreferrer&quot;&gt;Stozhkov et al, 2001&lt;/a&gt;). Under normal conditions, at 100 km you would be receiving approximately 500 times more radiation than in the surface (&lt;a href=&quot;https://srag.jsc.nasa.gov/spaceradiation/faq/faq.cfm&quot; rel=&quot;noreferrer&quot;&gt;ref1&lt;/a&gt;,&lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pubmed/12056428&quot; rel=&quot;noreferrer&quot;&gt;ref2&lt;/a&gt;), which is pretty much the same dose of outer space. That is not a big deal if you don't stay there very long. But auroras don't happen under normal conditions. However, radiation at surface levels during auroras go up but not by a large amount, so I don't think radiation will kill you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, if you get up there with a space suit that keep you alive, I think your quest to touch the aurora will be rather disappointing. However, the view from up there would be amazing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might want to see &lt;a href=&quot;https://www.youtube.com/watch?v=vlyavVJ-ZXE&quot; rel=&quot;noreferrer&quot;&gt;this video of a weather balloon sent up under an aurora&lt;/a&gt;. With cameras and radiation sensors. It is pretty cool, but it only got about a fifth of the way towards the aurora. And you can't get much higher with balloons, the &lt;a href=&quot;https://en.wikipedia.org/wiki/High-altitude_balloon&quot; rel=&quot;noreferrer&quot;&gt;world record (unmanned) is 53 km&lt;/a&gt;, which is just half way there. These are a couple screenshot from that video:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PmoQ4.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PmoQ4.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5nYUH.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5nYUH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-08-19T18:37:37.637" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14912" PostTypeId="2" ParentId="14903" CreationDate="2018-08-19T19:46:10.043" Score="7" Body="&lt;p&gt;Many animals can eat through plastic to get to what they really want to eat. Among them: termites, mice and myself when battling against a candy wrapper. However, as far as I understand, none of them can degrade the plastic. You can do the test yourself and I'll guarantee the plastic wrapper will come out the other end of your digestive system. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nevertheless, several organisms have been identified to be able to actually eat and digest plastics, among them:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;strong&gt;Bacteria&lt;/strong&gt;: Like &lt;a href=&quot;https://www.independent.co.uk/news/science/plastic-eating-bacteria-chemist-science-pollution-pet-recycling-a8311811.html&quot; rel=&quot;noreferrer&quot;&gt;&lt;em&gt;Ideonella sakaiensis&lt;/em&gt; discovered in japan&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Fungi&lt;/strong&gt;: Like &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0269749117300295&quot; rel=&quot;noreferrer&quot;&gt;Aspergillus tubingensis discovered in the landfills of Pakistan&lt;/a&gt;, or &lt;a href=&quot;https://aem.asm.org/content/77/17/6076.full&quot; rel=&quot;noreferrer&quot;&gt;Endophytic Fungi discovered in the Amazon&lt;/a&gt;, which seem to be edible, and there are some people offering small mushroom farms you can have at home to turn your polyester and polyurethane trash into food, they call it &quot;&lt;a href=&quot;http://www.livinstudio.com/fungi-mutarium/&quot; rel=&quot;noreferrer&quot;&gt;FUNGI MUTARIUM&lt;/a&gt;&quot;.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Insects larvae&lt;/strong&gt;: Like this &lt;a href=&quot;https://pubs.acs.org/doi/pdf/10.1021/es504038a&quot; rel=&quot;noreferrer&quot;&gt;plastic-eating waxworm&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;That said, it could be possible that some species of termites eat and digest some kinds of plastic. But I don't know of any reports of it. In the comments, Jan Doggen pointed to a &lt;a href=&quot;https://www.scidev.net/global/news/termites-may-hold-solution-to-polythene-waste.html&quot; rel=&quot;noreferrer&quot;&gt;2003 article of people working in that direction&lt;/a&gt;. But I guess given the lack of publications afterwards, it probably turned out that the termites were not digesting the plastics usefully. If you search the internet, you will find many references of termites chewing through plastics (&lt;a href=&quot;https://www.peststrategies.com/pest-guides/termite-guides/will-a-termite-eat-it/&quot; rel=&quot;noreferrer&quot;&gt;like this one&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="6298" LastEditDate="2018-08-19T21:01:12.000" LastActivityDate="2018-08-19T21:01:12.000" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14915" PostTypeId="1" AcceptedAnswerId="16043" CreationDate="2018-08-20T02:02:47.387" Score="14" ViewCount="2420" Body="&lt;p&gt;Many topics discussed here in Earth Science SE, tend to be about facts that are of consensus in the scientific community but not widely accepted by the general public. Instead, this one is widely accepted by the general public but it seems to generate doubts and debates between the leading scientists in the field.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We have always heard that Earth's magnetic field protects us from harmful &lt;a href=&quot;https://en.wikipedia.org/wiki/Cosmic_ray&quot; rel=&quot;noreferrer&quot;&gt;cosmic radiation&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_wind&quot; rel=&quot;noreferrer&quot;&gt;solar wind&lt;/a&gt;, that would otherwise &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_escape&quot; rel=&quot;noreferrer&quot;&gt;strip the atmosphere away&lt;/a&gt; and kill us all due to high doses ionizing radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Well, all that seem to actually be under debate. Because (if I understand the issue correctly), the magnetic field deflects most of the incoming charged particles, but on the other hand it increases dramatically the cross sectional area through which Earth interacts with the solar wind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This figure from Wikipedia's &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnetosphere&quot; rel=&quot;noreferrer&quot;&gt;Magnetosphere&lt;/a&gt; page will illustrate the problem:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/uMRSH.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uMRSH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, most of the charged particles are deflected away from Earth (orange lines), but a fraction of them gets funneled towards the poles through the so called &quot;polar cusps&quot; (yellow lines), that's why &lt;a href=&quot;https://en.wikipedia.org/wiki/Aurora&quot; rel=&quot;noreferrer&quot;&gt;auroras&lt;/a&gt; (a.k.a. northern lights) happen around the poles.&#xA;As you can see, the size of the polar cusps &quot;funnels&quot; is comparable to the size of the Earth, therefore giving rise to the discussion if the magnetic field increases or decreases the amount of charged particles that hit the atmosphere: If the funnels are smaller than the Earth the magnetic field would decrease the amount of particles hitting the Earth, but if the funnels are larger the particles hitting us would increase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These charged particles are usually cited as relevant due to two reasons:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;They are harmful to life by increasing the dose of ionizing radiation that reach the surface. Such radiation in turn generates mutations in the DNA.&lt;/li&gt;&#xA;&lt;li&gt;They can hit molecules in the atmosphere fast enough to send them to outer space, leading to &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_escape&quot; rel=&quot;noreferrer&quot;&gt;atmospheric escape&lt;/a&gt; and the thinning of our beloved atmosphere.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The first point is only partially true, because the atmosphere itself is an extraordinary shield against cosmic and solar radiation. Therefore, even in the eventual shutdown of Earth's magnetic field, not much radiation would reach the surface anyway. That's perhaps one of the reasons why nobody has been able to link &lt;a href=&quot;https://en.wikipedia.org/wiki/Geomagnetic_reversal&quot; rel=&quot;noreferrer&quot;&gt;magnetic reversals&lt;/a&gt; to mass extinctions. More on that is discussed in &lt;a href=&quot;https://earthscience.stackexchange.com/questions/14838/why-are-pole-reversals-not-more-detrimental-to-life/14844#14844&quot;&gt;this question&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second point is also questionable, because although the magnetic field does redirect the charged particles to the poles, it is unclear if the amount of particles currently hitting polar areas is more or less than the amount that would hit the entire Earth in the absence of a magnetic field. Notably, atmospheric escape would be equally bad if it happen distributed over the globe or if it is concentrated at the poles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is important to note that in this question I refer to the intrinsic magnetic field. Because, all bodies with atmosphere that are exposed to the solar wind develop an &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Venus#Induced_magnetosphere&quot; rel=&quot;noreferrer&quot;&gt;induced magnetic field&lt;/a&gt;. This induced magnetic field is observed in Venus, Mars and even comets. However, it is much weaker that Earth's intrinsic magnetic field.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The lack of intrinsic magnetic field is often blamed as one of the reasons that Mars lost its atmosphere. However, Venus have always challenged that idea: Venus have an atmosphere much thicker than Earth's and it doesn't have an intrinsic magnetic field. &lt;a href=&quot;https://www.space.com/11187-earth-magnetic-field-solar-wind.html&quot; rel=&quot;noreferrer&quot;&gt;This article from Space.com&lt;/a&gt; describes how this discussion was restarted due to:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;recent observations that show Mars and Venus are losing oxygen ions&#xA;  from their atmospheres into space at about the same rate as Earth&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And they cite &lt;a href=&quot;http://www-spc.igpp.ucla.edu/~strange/&quot; rel=&quot;noreferrer&quot;&gt;Robert Strangeway&lt;/a&gt; (a leading scientist in the field) saying &quot;My opinion is that the magnetic shield hypothesis is unproven&quot;.&#xA;Strangeway also presented a poster on last year's AGU fall meeting describing the same skepticism: &quot;&lt;a href=&quot;https://agu.confex.com/agu/fm17/meetingapp.cgi/Paper/265705&quot; rel=&quot;noreferrer&quot;&gt;Does an Intrinsic Magnetic Field Inhibit or Enhance Planetary Ionosphere Outflow and Loss?&lt;/a&gt;&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In that work he backs the above cite of Space.com with actual numbers:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The oxygen ion outflow is frequently assumed to be a proxy for the&#xA;  loss of water from the planetary atmosphere. In terms global outflow&#xA;  rates for the Earth the rate varies from $10^{25}$ to $10^{26}$&#xA;  s$^{−1}$, depending on geomagnetic activity. For both Venus and Mars&#xA;  global rates of the order $5 \times 10^{24}$ s$^{−1}$ have been&#xA;  reported.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Giving some credit to his skepticism, his work was cited in &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0019103517306917?via%3Dihub&quot; rel=&quot;noreferrer&quot;&gt;a 2018 paper&lt;/a&gt; written by most if not all the leading scientist behind the &lt;a href=&quot;https://en.wikipedia.org/wiki/MAVEN&quot; rel=&quot;noreferrer&quot;&gt;MAVEN probe&lt;/a&gt; that have been orbiting Mars since 2014. There they say:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;our expectation is that stripping of atmospheric gas by the solar wind&#xA;  is minimized by the presence of a magnetic field (e.g., Hutchins et al.,&#xA;  1997), although observations of escaping ions at Earth suggest that&#xA;  this may not be strictly correct (Strangeway et al.,2017).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The second author of that paper: Dave Brain, also gave a very interesting TED talk where he mentions the topic: &lt;a href=&quot;https://www.ted.com/talks/dave_brain_what_a_planet_needs_to_sustain_life&quot; rel=&quot;noreferrer&quot;&gt;What a planet needs to sustain life&lt;/a&gt; (starting at minute 7:31).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm fascinated by the topic, but my understanding of the physics of Earth's magnetic field is minimal. So I wonder: &lt;strong&gt;What evidence is there supporting that the intrinsic magnetic field really protects Earth's atmosphere and its living organisms?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words: In the absence of models and speculations of how the intrinsic magnetic field interacts with charged particles: &lt;strong&gt;Is there any reason to believe that a stronger magnetic field offers more protection than a weak or negligible one?&lt;/strong&gt; &lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-08-23T15:31:23.737" LastActivityDate="2021-09-06T03:09:17.890" Title="Does the magnetic field really protect Earth from anything?" Tags="|atmosphere|geomagnetism|solar-terrestrial-physics|paleomagnetism|magnetosphere|" AnswerCount="3" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="14920" PostTypeId="1" CreationDate="2018-08-20T15:13:47.760" Score="5" ViewCount="602" Body="&lt;p&gt;In India, Panchchuli, Kun Nun and Shilong only these mountain are claimed to be massif. Why other mountain formations are not termed as massif...? What are the characteristics of massif..?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anybody pls explain.&lt;/p&gt;&#xA;" OwnerUserId="13621" LastActivityDate="2018-08-20T15:25:06.523" Title="What is meant by Massif?" Tags="|geology|geomorphology|structural-geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14921" PostTypeId="2" ParentId="14920" CreationDate="2018-08-20T15:25:06.523" Score="3" Body="&lt;p&gt;A massif is an undisturbed solid rock mass, which is demarcated by e.g. faults. Massifs keep their internal structure and are displaced as a whole. Only mountains of mountain ranges fulfilling this criteria are called massifs. &lt;/p&gt;&#xA;" OwnerUserId="13398" LastActivityDate="2018-08-20T15:25:06.523" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14923" PostTypeId="1" CreationDate="2018-08-21T09:55:53.603" Score="1" ViewCount="26" Body="&lt;p&gt;I hope this is the right venue for my question.&#xA;I'm trying to find the conversion factor between vehicular CO2 emissions (in units of mass, e.g. in metric tons) and the energy generated (in kWh).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I understand correctly I found an emission factor for electricity on EPA's &lt;a href=&quot;https://www.epa.gov/energy/greenhouse-gases-equivalencies-calculator-calculations-and-references&quot; rel=&quot;nofollow noreferrer&quot;&gt;site&lt;/a&gt;    - 7.44 × 10^-4 metric tons CO2/kWh.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I assume that the energy efficiency of an average car is different from that of the average power plant, so this will probably not be very useful to estimate the emission factor of vehicles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would greatly appreciate a source that could provide this conversion factor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many thanks!&lt;/p&gt;&#xA;" OwnerUserId="13677" LastEditorUserId="13677" LastEditDate="2018-08-21T13:28:42.170" LastActivityDate="2018-08-21T13:28:42.170" Title="Finding the emission factor for vehicular energy generation" Tags="|environmental-protection|fossil-fuel|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14924" PostTypeId="1" CreationDate="2018-08-21T12:43:25.193" Score="5" ViewCount="165" Body="&lt;p&gt;I heard in tv show, there are water channels in underground like rivers or small channels! So I just wondered why don't we use such underground water channels to recharge the underground water of one area from another area, incase there are connections?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm sure if there are channels, scientists would have been done some research about it?  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;So, Do we have any underground water channels maps for world wide?&lt;/li&gt;&#xA;&lt;li&gt;Do you think its possible to recharge lakes few miles away from river using this idea?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="13678" LastActivityDate="2018-08-27T19:28:56.240" Title="Transferring water using underground channel" Tags="|water|geography|groundwater|underground-water|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14925" PostTypeId="2" ParentId="14924" CreationDate="2018-08-21T13:17:55.917" Score="1" Body="&lt;p&gt;1) I don't believe there is a fully global map as some parts/countries of the world are inaccessible for varying reasons; however, there are a number of maps available for areas around the world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Possibly, but it depends on a few factors. I think the cost would exceed the effort required to either reroute a subterranean river or produce enough pressure to keep the lake filled from below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I might be wrong, but aside from a &quot;spring fed&quot; lake that can withstand a drought, most of the other lakes are either made from low basins along a river's path, as a result of tectonics, or created artificially by animals like a beaver and us.&lt;/p&gt;&#xA;" OwnerUserId="13276" LastActivityDate="2018-08-21T13:17:55.917" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14932" PostTypeId="1" AcceptedAnswerId="14933" CreationDate="2018-08-22T05:45:29.730" Score="4" ViewCount="123" Body="&lt;p&gt;In his recent &lt;a href=&quot;https://twitter.com/Astro_Feustel/status/1031535460655554560&quot; rel=&quot;nofollow noreferrer&quot;&gt;tweet&lt;/a&gt; from the International Space Station as it's current &lt;a href=&quot;https://en.wikipedia.org/wiki/Expedition_56&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mission 56&lt;/a&gt; Commander, NASA astronaut &lt;a href=&quot;https://en.wikipedia.org/wiki/Andrew_J._Feustel&quot; rel=&quot;nofollow noreferrer&quot;&gt;Andrew J. Feustel&lt;/a&gt; says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This is #Indonesia as viewed from the @Space_Station. With the low clouds it is easy to see the peaks of the volcanoes associated with the Sunda Megathrust subduction zone that lies at the tectonic boundary of the Indo-Australian and Eurasian plates.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I can't visualize where these are on Earth, mostly because of the cloud cover in the image. Where is this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/D8i0c.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/D8i0c.jpg&quot; alt=&quot;Indonesian Volcanos from Space&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T20:51:26.017" LastActivityDate="2019-08-28T20:51:26.017" Title="Where are these volcanos as seen in this space tweet?" Tags="|geology|volcanology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14933" PostTypeId="2" ParentId="14932" CreationDate="2018-08-22T06:41:56.653" Score="6" Body="&lt;p&gt;This was taken looking from around above or near Western Australia, looking north. You can see a fuzzy green patch to the centre and left of the photo. That's the eastern part of Java.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's the image where I labelled some of the volcanoes, and a reference image from Google Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ShpbU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ShpbU.jpg&quot; alt=&quot;original labelled&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mbJpS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mbJpS.jpg&quot; alt=&quot;google earth&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2018-10-19T02:21:27.620" LastActivityDate="2018-10-19T02:21:27.620" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14936" PostTypeId="1" CreationDate="2018-08-22T15:11:38.340" Score="2" ViewCount="113" Body="&lt;p&gt;Let's say some event caused runaway glacial melt, and removed half of the ice currently locked away in specific areas of the planet. Would the significant weight changes on various plates and fault lines be enough to dramatically shift how current plates were biased against one another?&lt;/p&gt;&#xA;" OwnerUserId="13686" LastActivityDate="2018-08-31T08:29:01.947" Title="Could glacial melt alter plate tectonic movement?" Tags="|climate-change|plate-tectonics|seismology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14937" PostTypeId="1" CreationDate="2018-08-23T16:44:44.403" Score="4" ViewCount="182" Body="&lt;p&gt;My understanding of a storm surge is that it is caused by the hurricane &quot;pushing&quot; water towards the land. When a hurricane makes landfall, this water washes up on the short generating a storm surge. From the Wikipedia article, certain geographical features such as shallow water or a funnel-shaped landfall point can exacerbate surges since the water pushed by the storm cannot dissipate (&lt;a href=&quot;https://en.wikipedia.org/wiki/Storm_surge&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Storm_surge&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, when a hurricane strikes a small island, is the storm surge usually not as much of a problem since the water can dissipate around the island? Are islands thus often less affected by the flooding aspect of hurricanes vs. mainland landfall locations?&lt;/p&gt;&#xA;" OwnerUserId="13692" LastActivityDate="2018-08-23T16:44:44.403" Title="Are hurricane storm surges smaller when the storms strike small islands?" Tags="|tropical-cyclone|storms|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14940" PostTypeId="1" CreationDate="2018-08-23T21:21:44.693" Score="3" ViewCount="227" Body="&lt;p&gt;Looking at an arc welder is bad, it is a source that emits on a broad range of the electromagnetic spectrum. More specifically the blue and UV are particularly bad for vision:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Artificial sources of UV radiation also cause corneal damage. Injury&#xA;  from a welder's arc commonly is known as flash burn, welder's flash,&#xA;  or arc eye. Other sources of UV radiation injury include sun tanning&#xA;  beds, carbon arcs, photographic flood lamps, lightning, electric&#xA;  sparks, and halogen desk lamps. Several outbreaks of ultraviolet&#xA;  keratitis have been observed in the United States after installation&#xA;  of improper lighting in school gymnasiums, resulting in high levels of&#xA;  UV radiation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://emedicine.medscape.com/article/799025-overview&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://emedicine.medscape.com/article/799025-overview&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does lightning release the same magnitude of electromagnetic emissions as an arc wielder, in UVA, UVB or UVC spectra? Could watching lightning repeatedly degrade human vision?&lt;/p&gt;&#xA;" OwnerUserId="6949" LastEditorUserId="6949" LastEditDate="2018-08-27T16:18:29.400" LastActivityDate="2018-08-27T16:18:29.400" Title="Does lightning release the same electromagnetic emmisions as an arc welder?" Tags="|lightning|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="14941" PostTypeId="1" CreationDate="2018-08-23T22:42:38.107" Score="4" ViewCount="43" Body="&lt;p&gt;On &quot;July 25, 2016 a thin river of purple light slashed through the skies of northern Canada in an arc that seemed to stretch hundreds of miles into space. It was a magnificent, mysterious, borderline-miraculous sight, and the group of citizen skywatchers who witnessed it decided to give the phenomenon a fittingly majestic name: '&lt;a href=&quot;https://www.livescience.com/58809-new-aurora-feature-named-steve-investigated.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Steve&lt;/a&gt;.'&quot; (LiveScience: &lt;a href=&quot;https://www.livescience.com/63385-steve-not-aurora-mystery-phenomenon.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Eerie Sky Glow Called 'Steve' Isn't an Aurora, Is 'Completely Unknown' to Science&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DJyR6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DJyR6.jpg&quot; alt=&quot;full horizontal steve&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This event was thought to just be a feature of the northern lights, but &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL078509&quot; rel=&quot;nofollow noreferrer&quot;&gt;this is now being questioned&lt;/a&gt; and there may be no simple explanation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;According to researchers at the University of Calgary in Canada and the University of California, Los Angeles, Steve does not contain the telltale traces of charged particles blasting through Earth's atmosphere that auroras do. Steve, therefore, is not an aurora at all, but something entirely different: a mysterious, largely unexplained phenomenon that the researchers have dubbed a 'sky glow.'&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qFR3i.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qFR3i.jpg&quot; alt=&quot;multiple shots of steve&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has anyone performed any modeling or triangulation calculations in 3D space on the globe to estimate where it was located and its possible &quot;end points&quot; in relation to the Earth?&lt;/p&gt;&#xA;" OwnerUserId="2575" LastActivityDate="2018-08-23T22:42:38.107" Title="Modeling &amp; triangulation of &quot;STEVE&quot; along with its accompanying possible &quot;end points&quot; in relation to the Earth?" Tags="|auroras|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14942" PostTypeId="1" AcceptedAnswerId="14954" CreationDate="2018-08-24T10:15:27.223" Score="8" ViewCount="109" Body="&lt;p&gt;Happened to see notice of fairly strong earthquakes near &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/eventpage/us1000gcii#executive&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fiji&lt;/a&gt; and &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/eventpage/us1000ggj4#executive&quot; rel=&quot;nofollow noreferrer&quot;&gt;Peru&lt;/a&gt; within the past few days, and thought I'd find they had been fairly damaging... only to find the impacts were quite minimal.  Have to think maybe that relates to the depths they occurred at (563 km and 610 km)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems like an overall busy period, with earthquakes in/near &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/map/#%7B%22autoUpdate%22%3A%5B%5D%2C%22basemap%22%3A%22grayscale%22%2C%22feed%22%3A%221534712794451%22%2C%22listFormat%22%3A%22default%22%2C%22mapposition%22%3A%5B%5B-9.663030792615071%2C114.64233398437499%5D%2C%5B-7.623886853120036%2C118.157958984375%5D%5D%2C%22overlays%22%3A%5B%22plates%22%5D%2C%22restrictListToMap%22%3A%5B%22restrictListToMap%22%5D%2C%22search%22%3A%7B%22id%22%3A%221534712794451%22%2C%22name%22%3A%22Search%20Results%22%2C%22isSearch%22%3Atrue%2C%22params%22%3A%7B%22starttime%22%3A%222018-07-01%2000%3A00%3A00%22%2C%22endtime%22%3A%222018-08-19%2023%3A59%3A59%22%2C%22maxlatitude%22%3A-7.994%2C%22minlatitude%22%3A-9.297%2C%22maxlongitude%22%3A117.081%2C%22minlongitude%22%3A115.719%2C%22minmagnitude%22%3A5%2C%22orderby%22%3A%22time%22%7D%7D%2C%22sort%22%3A%22newest%22%2C%22timezone%22%3A%22utc%22%2C%22viewModes%22%3A%5B%22list%22%2C%22map%22%5D%2C%22event%22%3A%22us1000g3ub%22%7D&quot; rel=&quot;nofollow noreferrer&quot;&gt;Indonesia&lt;/a&gt;, &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/eventpage/us1000gez7#executive&quot; rel=&quot;nofollow noreferrer&quot;&gt;Venezuela&lt;/a&gt;, and &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/eventpage/us1000gf8u#executive&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oregon&lt;/a&gt; as well in about the last week.  But I do feel like I've seen similar bursts in the past.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I'm naively not sure I've ever seen such deep ones reported where they apparently didn't cause much shaking.  I figure that may well be just because such earthquakes having minimal impacts simply weren't as publicized in the past??&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But, not knowing nearly enough about the differences in earthquake types and patterns, I'd be interested to know:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Were the minimal impacts indeed a consequence of the depths of the earthquakes?  &lt;/li&gt;&#xA;&lt;li&gt;Are such strong earthquakes at those depths expected at fairly similar regularity to similar earthquakes at shallower depths?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-08-27T15:52:48.097" LastActivityDate="2022-01-04T01:22:29.873" Title="Are strong deep earthquakes that result in minimal impacts common?" Tags="|earthquakes|natural-disasters|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14943" PostTypeId="1" CreationDate="2018-08-24T12:02:32.087" Score="4" ViewCount="57" Body="&lt;p&gt;I have recently been given the task of developping a coastal model for tides. I have a few requirements, it must not be time stepping in order to be as fast as possible and in finite differences because something as simple as possible is asked.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a first start, I tried implementing linearized shallow water equations and supposed a time dependancy in the form of a complex exponential. This gave me the following system :&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1) $-i \omega \hat u -f \hat v +g \partial_x \hat h= -r \hat u$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) $-i \omega \hat v +f \hat u +g \partial_y\hat h= -r \hat v$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(3) $-i \omega \hat h + \partial_x H\hat u + \partial_y H\hat v = 0$ &lt;/p&gt;&#xA;&#xA;&lt;p&gt;where my unknows are $\hat u$,$\hat v$,$\hat h$, and only two parameters possibly showing spatial variation : $r$ and $H$. I tried to discretize it with finite differences but I quickly realize that I needed to be very careful with my boundary conditions. Because the 3 variables that I wanted to determined where closely linked to one another and that actually $\hat u$ and $\hat v$ could easily be determined by the derivatives of $\hat h$.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I modified my system  in order to solve only this variable and came with the following set of equations :&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(4) $ \hat u = \frac{-g(r-i \omega)\partial_x \hat h -fg\partial_y \hat h}{f²+(r-i\omega)²}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(5) $ \hat v = \frac{-g(r-i \omega)\partial_y \hat h +fg\partial_x \hat h}{f²+(r-i\omega)²}$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(6) $ i \omega \hat h = \partial_x(\frac{H}{f²+(r-i\omega)²}(-g(r-i \omega)\partial_x \hat h -fg\partial_y \hat h)) + \partial_y(\frac{H}{f²+(r-i\omega)²}(-g(r-i \omega)\partial_y \hat h +fg\partial_x \hat h)) $&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then I tried to approximate the derivates with centered first order scheme. I tried to reproduce a Kelvin coastal wave on a reduced domain (10*10 cells). However, I am at best able not to crash it and most of the time have very strong oscillations in the center. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is the code I use :&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;#******Packages import*#&#xA;import numpy as np&#xA;import matplotlib.pyplot as plt&#xA;&#xA;#******solving function**#&#xA;&#xA;def solver_water_elevation(eta,depth,dx,dy,r,f=2e-4,sigma=2e-5,g=9.81):&#xA;&#xA;    &quot;&quot;&quot;Solver of linearized elliptic shallow water equation for complex coastal&#xA;    problems. We use a jacobi iterator in a first place. Then we will refine it.&#xA;    Variables here are mostly complex-valued.&#xA;    INPUTS:&#xA;    eta : Overelevation (m)&#xA;    depth : depth (m)&#xA;    dx,dy : Size of grid cell&#xA;    r : Linear friction coefficient (m.s-1)&#xA;    f : Coriolis frequency (s-1)&#xA;    sigma : Frequency of the considered wave (s-1)&#xA;    g : Gravitationnal acceleration (m.s-2)&#xA;    OUTPUTS :&#xA;    eta : See above&quot;&quot;&quot;&#xA;&#xA;    # First we determine the local friction coefficient in m-1&#xA;    friction=r/depth&#xA;    #Then we will proceed step by step&#xA;    # First we compute gradients of eta&#xA;    etadx=(eta[1:-1,2]-eta[1:-1,:-2])/(2.*dx[1:-1,1:-1])&#xA;    etady=(eta[2:,1:-1]-eta[:-2,1:-1])/(2.*dy[1:-1,1:-1])&#xA;&#xA;    # Now we can compute components associated with zonal and meridional speed&#xA;    u=-g*(friction[1:-1,1:-1]-1j*sigma)*etadx-f*g*etady&#xA;    v=-g*(friction[1:-1,1:-1]-1j*sigma)*etady+f*g*etadx&#xA;#    print('v',v)&#xA;&#xA;    # Now we multiply them so that they correspond to the right terms&#xA;    multiplicator=depth[1:-1,1:-1]/(f**2+(friction[1:-1,1:-1]-1j*sigma)**2)&#xA;    print('multiplicator',multiplicator)&#xA;    #Now we compute the gradient of those terms&#xA;    dxu=(multiplicator[1:-1,2:]*u[1:-1,2:]-multiplicator[1:-1,:-2]*u[1:-1,:-2])\&#xA;        /(2.*dx[2:-2,2:-2])&#xA;    dyv=(multiplicator[2:,1:-1]*v[2:,1:-1]-multiplicator[:-2,1:-1]*v[:-2,1:-1])\&#xA;        /(2.*dy[2:-2,2:-2])&#xA;    # And finally, determine eta&#xA;    eta[2:-2,2:-2]=-1j/sigma*(dxu+dyv)&#xA;&#xA;    return eta&#xA;&#xA;def simple_convergence_error(eta,eta_old):&#xA;    &quot;&quot;&quot;Compare the value of 2 array of eta and returns the maximum              relative error.&#xA;&#xA;    INPUTS :&#xA;    eta : New array &#xA;    eta_old :old array&#xA;    OUTPUTS :&#xA;    error : Maximal relative difference between the two arrays&quot;&quot;&quot;&#xA;&#xA;    return np.max(abs((eta-eta_old)))&#xA;&#xA;def sol_Kelvin_wave(depth,grid_size,dx,dy,f=2e-4,&#xA;                    sigma=2.31484e-5,g=9.81,h_0=1.+0.5j) :&#xA;    &quot;&quot;&quot; Here we compute the analytical solution of Kelvin waves&#xA;    for the conditions given in the BC.&#xA;&#xA;    INPUTS:&#xA;    depth : Static water depth, in meters&#xA;    grid_size : size of the grid (in number of cells)&#xA;    dx,dy : Size of a grid cell in x and y directions, in meters&#xA;    f : Coriolis frequency, in s-1&#xA;    sigma : Frequency of the given tide in s-1&#xA;    g : Gravity acceleration, in m.s-2&#xA;    h_0 : Initial overelevation, in m (Complex valued)&#xA;    OUTPUTs:&#xA;    eta : Overelevation of water&quot;&quot;&quot;&#xA;&#xA;    # First we set some useful values&#xA;    c=np.sqrt(g*depth)&#xA;    omega=sigma*2.*np.pi # We get in rad.s-1&#xA;    k=omega/c # The wavevector&#xA;&#xA;    # We must determine the distance to boundaries&#xA;    X_pos=np.array([[dx[0,j]/2. + dx[:i,j].sum() &#xA;        for j in range(grid_size[1])] &#xA;        for i in range(grid_size[0])])&#xA;    Y_pos=np.array([[dy[i,0]/2. + dy[i,:j].sum()&#xA;        for j in range(grid_size[1])] &#xA;        for i in range(grid_size[0])])&#xA;&#xA;    # Computing the value&#xA;    eta=h_0*np.exp(1.j*k[:,:]*X_pos[:,:])\&#xA;        *np.exp(-f*Y_pos[:,:]/c[:,:])&#xA;&#xA;    return eta&#xA;&#xA;#******Defining variables*****#&#xA;nx,ny=10,10&#xA;eta=np.zeros((nx,ny),dtype=complex)&#xA;dx,dy=10.*np.ones((nx,ny)),10.*np.ones((nx,ny))&#xA;sigma=2e-4 # frequency&#xA;f=2e-4 # Coriolis frequency&#xA;r=0.#2.5e-3 # Friction coefficient&#xA;depth=np.ones((nx,ny)) # Constant depth&#xA;&#xA;#***I try to initialize it with a analytic solution***#&#xA;eta_test=sol_Kelvin_wave(depth,(nx,ny),dx,dy,f,sigma)&#xA;# And now I set the boundary conditions&#xA;eta[:2,:]=eta_test[:2,:] # Bottom&#xA;eta[-2:,:]=eta_test[-2:,:] # Upper side&#xA;eta[:,:2]=eta_test[:,:2] # Left side&#xA;eta[:,-2:]=eta_test[:,-2:] #Right side&#xA;#*****Calling the solver**********#&#xA;&#xA;error=1. # Initialzing the error&#xA;tol=1e-8 # Tolerance to error&#xA;nbr_iter=0&#xA;&#xA; while error&amp;gt;tol : # We use a simple iterative solver&#xA;    # Counting the iterations&#xA;    nbr_iter+=1&#xA;    eta_old=eta.copy()# Saving the old value&#xA;    #Calling the solver&#xA;    eta=solver_water_elevation(eta,depth,dx,dy,r,sigma=sigma*2.*np.pi,f=f)&#xA;    #Checking the error&#xA;    error=simple_convergence_error(eta,eta_old)&#xA;    print('Computed in ',nbr_iter,' iterations')&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Is there a clear error in my code ? Or am I just trying to solve my problem with unadapted tools ? It seems very basic but still it is clearly running out of my hands. And I found only little litterature about elliptic equations for tide computing. So I guessed it was not very efficient but I was totally unable to find a good explanation of why it was so inefficient.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for your help, and sorry if it seems really basic.&lt;/p&gt;&#xA;" OwnerUserId="13171" LastEditorUserId="111" LastEditDate="2018-08-24T14:41:51.080" LastActivityDate="2018-08-24T14:41:51.080" Title="Simple numerical model of tide with an elliptic scheme" Tags="|models|tides|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14946" PostTypeId="1" CreationDate="2018-08-25T13:20:41.720" Score="5" ViewCount="636" Body="&lt;p&gt;As far as &lt;a href=&quot;https://en.wikipedia.org/wiki/Charnockite&quot; rel=&quot;nofollow noreferrer&quot;&gt;charnockites&lt;/a&gt; are concerned, granitic charnockites are formed due to palingenetic fusion and &lt;a href=&quot;https://en.wikipedia.org/wiki/Metasomatism&quot; rel=&quot;nofollow noreferrer&quot;&gt;metasomatism&lt;/a&gt;, while granulitic charnockites are formed due to high grade &lt;a href=&quot;https://en.wikipedia.org/wiki/Metamorphism&quot; rel=&quot;nofollow noreferrer&quot;&gt;metamorphism&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;When I googled for palingenetic fusion, I haven't gotten any clear vision. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone help me to grab the answer for my question?&lt;/p&gt;&#xA;" OwnerUserId="13621" LastEditorUserId="725" LastEditDate="2018-10-23T10:57:55.230" LastActivityDate="2018-10-23T10:57:55.230" Title="How does palingenetic fusion occur in rock?" Tags="|geology|minerals|terminology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14952" PostTypeId="1" CreationDate="2018-08-27T13:57:18.190" Score="2" ViewCount="367" Body="&lt;p&gt;Why is it that flying west takes longer than flying east despite the fact that the Earth is rotating eastward around its own axis?  I had always thought flying west would take shorter than flying east but after a few round trips from New York to San Francisco I've found that it's just the opposite.  The same when flying from London to Moscow: flying east is always quicker.&lt;/p&gt;&#xA;" OwnerUserId="6370" LastActivityDate="2018-08-27T17:32:28.740" Title="Flight time differences between flying east and flying west" Tags="|earth-rotation|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14953" PostTypeId="1" CreationDate="2018-08-27T14:56:53.483" Score="2" ViewCount="82" Body="&lt;p&gt;In which type of magma can I find magnetite? Peraluminous or peralkaline? I've been looking and the peraluminous magma have a lot of oxides so I thought it would be reduced magma so it would have magnetite but I'm not pretty sure.&lt;/p&gt;&#xA;" OwnerUserId="13708" LastActivityDate="2018-10-26T19:00:11.380" Title="The magnetite is in which type of magma" Tags="|geology|geochemistry|igneous|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14954" PostTypeId="2" ParentId="14942" CreationDate="2018-08-27T15:37:35.687" Score="2" Body="&lt;p&gt;Depends where you are in the world, New Zealand has a combination of deep and shallow earthquakes, the shallow ones are associated with the slip-strike faults in the south. The deeper ones on the other hand occur where subduction is the dominant tectonic scheme in the north island, particularly in central and eastern areas. A deep earthquake of a given magnitude will cause considerably less damage to human artifacts than a shallow one; there's more, and softer, rock between the rupture zone and the surface to absorb the energy of the 'quake. If they're deep enough then the hot, plastic, rocks between the rupture and the surface will in fact block most of the L and R shear waves that often cause the most surface damage.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="10735" LastEditDate="2022-01-04T01:22:29.873" LastActivityDate="2022-01-04T01:22:29.873" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14955" PostTypeId="2" ParentId="14952" CreationDate="2018-08-27T16:08:52.697" Score="4" Body="&lt;p&gt;The Jet Stream is the cause for slower flight times to the West. It flows from West to East at high altitudes and therefore helps planes flying East but causes extra resistance for planes flying West.&lt;/p&gt;&#xA;" OwnerUserId="13710" LastActivityDate="2018-08-27T16:08:52.697" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14956" PostTypeId="2" ParentId="14952" CreationDate="2018-08-27T17:32:28.740" Score="1" Body="&lt;p&gt;I had a similar misconception some time ago.  Because the earth is rotating it seems that if you go counter to the rotation the trip will be faster.  Unfortunately, All the earth is rotating, including the plane you may ride in, if you fly east or west you have to accelerate the same amount to go the same speed east or west, all other influences being equal.  In the case of travel, at least in the Northern hemisphere all things are not equal because of the jet stream that Julian mentioned in the previous answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I specifically mentioned east west motion because when you travel east to west your relative speed based on your location does not change, but if you travel north or south the surface speed of the earth's rotation changes with latitude.  The rotation speed at the equator is just over 1600 kph, but at 45 deg N it is just under 1200 kph, and at 90 deg N it is 0 kph.  The change is gradual and for the most part is not noticeable to most people, but it has significant effects when looking at the large air movements of storms.  The Coriolis effect, is what causes the low pressure storms in the northern hemisphere to rotate counter clockwise.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;https://en.wikipedia.org/wiki/Coriolis_force&quot; rel=&quot;nofollow noreferrer&quot;&gt;Coriolis Force Wikipeda&lt;/a&gt;  Skip to the Applied to Earth Section.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2018-08-27T17:32:28.740" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14957" PostTypeId="2" ParentId="14953" CreationDate="2018-08-27T17:56:35.307" Score="1" Body="&lt;p&gt;Probably both but I'd expect to see more in a peraluminous melt. The more &lt;a href=&quot;https://en.wikipedia.org/wiki/Mafic&quot; rel=&quot;nofollow noreferrer&quot;&gt;mafic&lt;/a&gt; the melt the more iron based mineralisation you're going to see.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-08-27T17:56:35.307" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14958" PostTypeId="2" ParentId="14924" CreationDate="2018-08-27T18:00:35.337" Score="1" Body="&lt;p&gt;Be aware that ducts lack the filtration process that bedrock often affords, and that you may introduce raw materials that are toxic to some of the ecosystem for the lake/etc.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As long as that's not an issue, then there's no implicit reason you could not.  If you try to use geological formations for channeling the underground water, you suffer the risk of losing water to infiltration of the surrounding media.  &lt;/p&gt;&#xA;" OwnerUserId="2441" LastActivityDate="2018-08-27T18:00:35.337" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14960" PostTypeId="2" ParentId="14924" CreationDate="2018-08-27T19:28:56.240" Score="3" Body="&lt;p&gt;This is already used in some cases. The one I'm familiar with is California's Coachella Valley, best known as the home to Palm Springs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Farms, golf courses, other businesses, and homes pump far more water out of the region's aquifer than is restored by normal rainfall, so &lt;a href=&quot;http://www.cvwd.org/162/Groundwater-Replenishment-Imported-Water&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Coachella Valley Water District pipes in water from the Colorado River and, basically, pours it into the sand at the high end of the 15-mile-long valley.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This water then percolates through the sandy soil down the valley; it's retrieved through local wells. One advantage to delivering the water through the aquifer is that it avoids loss through evaporation.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Coachella Valley’s groundwater basin can be imagined as a tilted&#xA;  bathtub filled with sand and gravel and topped with a layer of clay;&#xA;  water fills the spaces under the clay and in between the sand and&#xA;  gravel. &lt;a href=&quot;http://www.cvwd.org/154/Where-does-my-water-come-from&quot; rel=&quot;nofollow noreferrer&quot;&gt;--Coachella Valley Water District&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This system works because:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;There is a (relatively) plentiful external source of water.&lt;/li&gt;&#xA;&lt;li&gt;The local geology allows water to flow.&lt;/li&gt;&#xA;&lt;li&gt;The replenishment is largely powered and directed by gravity, which makes it cheap and avoids having to pump water into a system that already has liquid in it and having to worry about whether the water is going where you want.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://waterinthewest.stanford.edu/groundwater/recharge/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This Stanford University project talks about the opportunities and challenges for aquifer recharge projects&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2018-08-27T19:28:56.240" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14961" PostTypeId="1" CreationDate="2018-08-27T20:03:02.443" Score="6" ViewCount="944" Body="&lt;p&gt;I read that the source of Karst topography is coral reefs, when coral reefs are found in water bodies, how is karst topography formed on land?&lt;/p&gt;&#xA;" OwnerUserId="13714" LastActivityDate="2018-08-27T22:39:33.360" Title="How is Karst topography formed on land?" Tags="|planetary-formation|topography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14962" PostTypeId="1" CreationDate="2018-08-27T21:43:57.410" Score="1" ViewCount="58" Body="&lt;p&gt;Found this in a river. The dark part is the rock still drying out. I think the smoothness is the weathering from the river. The rock is heavy and a little bit rough on the underside among the smoothness. I noticed it because it set my metal detecting pin pointer off and it is magnetic. Not sure what the brown/orange stuff is. Hardness is defo 5.5 as it scratches glass. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Found in a carboniferous zone and other deposits nearby are quartz and limestone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3XweD.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3XweD.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13715" LastEditorUserId="595" LastEditDate="2018-08-28T08:28:41.473" LastActivityDate="2018-08-28T08:28:41.473" Title="Rock ID: Dark, Hard, Midland Valley Scotland" Tags="|geology|" AnswerCount="0" CommentCount="2" ClosedDate="2019-08-31T09:25:51.717" ContentLicense="CC BY-SA 4.0" />
  <row Id="14963" PostTypeId="2" ParentId="14961" CreationDate="2018-08-27T22:09:55.180" Score="5" Body="&lt;p&gt;Karst topography on land is characterized by sinkholes, springs, losing streams, and caves.  They are formed by the dissolution of easily dissolved carbonate rock such as limestone and dolomite.  The rock is dissolved by carbonic acid in rain.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;https://en.wikipedia.org/wiki/Karst&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The carbonic acid that causes karstic features is formed as rain&#xA;  passes through the atmosphere picking up carbon dioxide (CO2), which&#xA;  dissolves in the water. Once the rain reaches the ground, it may pass&#xA;  through soil that can provide much more CO2 to form a weak carbonic&#xA;  acid solution, which dissolves calcium carbonate. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Here is an illustration of karst topography: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/t67c9.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/t67c9.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source:  &lt;a href=&quot;http://www.wandelgek.nl/?p=18828&amp;amp;lang=en&quot; rel=&quot;noreferrer&quot;&gt;//www.wandelgek.nl/?p=18828&amp;amp;lang=en&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is an illustration of karst formation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Tw8p4.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Tw8p4.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source:  &lt;a href=&quot;http://slideplayer.com/slide/3400196/&quot; rel=&quot;noreferrer&quot;&gt;http://slideplayer.com/slide/3400196/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastEditorDisplayName="user11318" LastEditDate="2018-08-27T22:39:33.360" LastActivityDate="2018-08-27T22:39:33.360" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14966" PostTypeId="1" CreationDate="2018-08-28T08:21:18.387" Score="2" ViewCount="428" Body="&lt;p&gt;Are therms &quot;&lt;strong&gt;&lt;em&gt;contact aureole&lt;/em&gt;&lt;/strong&gt;&quot; and &quot;&lt;strong&gt;&lt;em&gt;thermal aureole&lt;/em&gt;&lt;/strong&gt;&quot; synonyms? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found some sentence at A. M. PATWARDHAN (2012): &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;The peripheral extent up to which the thermal effect of the intrusion&#xA;  is observed is referred to as the contact or thermal aureole of the&#xA;  intrusive body.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="13720" LastActivityDate="2018-08-28T17:10:42.193" Title="Difference between thermal and contact aureole" Tags="|petrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14967" PostTypeId="2" ParentId="14966" CreationDate="2018-08-28T09:28:39.620" Score="3" Body="&lt;p&gt;&lt;strong&gt;&lt;em&gt;Contact aureole&lt;/em&gt;&lt;/strong&gt;, &lt;strong&gt;&lt;em&gt;thermal aureole&lt;/em&gt;&lt;/strong&gt; and &lt;strong&gt;&lt;em&gt;metamorphic aureole&lt;/em&gt;&lt;/strong&gt; are all synonyms referring to the peripheral aureole of recrystallized rocks around an intrusion of an igneous body due to the heat flux between the intrusion and the box rock. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can read several examples quoting both terms as synonyms:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Metamorphism#Contact_(thermal)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; article on metamorphic types includes a section heading of  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Contact (thermal)&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And another example is &lt;a href=&quot;https://www.frontiersin.org/articles/10.3389/feart.2017.00082/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;frontiersin.org&lt;/a&gt; where the subject regularly interchanges the terms to prevent monotony in the writing.&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorUserId="6298" LastEditDate="2018-08-28T17:10:42.193" LastActivityDate="2018-08-28T17:10:42.193" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14973" PostTypeId="2" ParentId="12230" CreationDate="2018-08-29T15:04:58.303" Score="1" Body="&lt;p&gt;At the current moment, none that are in operaational use. The problem with using expected measurements is that there may be multiple drastically different estimates, and then there is the problem of errors creating misclassification. There have been attempts, but none of them that are noteworthy or operationally used, that I know of.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.jstor.org/stable/4300369?seq=6#page_scan_tab_contents&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; may be relevant to your question. &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/WAF-D-14-00014.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; may also be relevant, but is obviously dated considering the events of Hurricane Harvey. Harvey also highlighted the problem of rainfall relative to runoff, which is significant in urban areas and concave/parabolic topography.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2018-08-29T15:04:58.303" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="14974" PostTypeId="1" AcceptedAnswerId="15121" CreationDate="2018-08-29T17:40:26.003" Score="8" ViewCount="396" Body="&lt;p&gt;I live in a generally geographically active area (Southern California, near the San Andreas fault, if that matters), that has had two relatively minor earthquakes that I have felt in the last week (in the 3-4 range on the Richter Scale, I believe), as well as frequently in the past. I am used to this, being born and raised in the region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was talking about these phenomena with a colleague who recently moved to the area from a non-earthquake prone place, and was not used to them. I realized that both of the earthquakes were late at night, when I was in bed, and searching my memory I can only recall encountering these minor earthquakes at similar times.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question, therefore, is if there is any correlation between time of day and earthquakes? Or to put it another way, is my observation based on anything more than the fact that I am more likely to note and recall a minor earthquake what I am not engaged in another activity?&lt;/p&gt;&#xA;" OwnerUserId="13729" LastActivityDate="2018-09-18T10:00:10.500" Title="Seeming correlation between time of day and earthquakes" Tags="|geology|geophysics|earthquakes|earth-observation|time|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14977" PostTypeId="1" AcceptedAnswerId="14979" CreationDate="2018-08-30T13:14:17.207" Score="2" ViewCount="96" Body="&lt;p&gt;Can anyone tell me which crop is this. Clicked in France in Aug!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LDSRw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LDSRw.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13078" LastActivityDate="2018-08-30T13:51:32.517" Title="Which crop is this?" Tags="|agriculture|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14979" PostTypeId="2" ParentId="14977" CreationDate="2018-08-30T13:51:32.517" Score="2" Body="&lt;p&gt;It looks like &lt;a href=&quot;https://en.wikipedia.org/wiki/Cannabis&quot; rel=&quot;nofollow noreferrer&quot;&gt;cannabis&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mature cannabis plants are are tall &amp;amp; &quot;skinny&quot;, like the ones in the picture. Also, the density of plants, per unit area of land, suggests it's a plantation crop, quite possibly for illicit purposes.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-08-30T13:51:32.517" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14980" PostTypeId="1" AcceptedAnswerId="14982" CreationDate="2018-08-30T14:05:01.323" Score="4" ViewCount="441" Body="&lt;p&gt;Why are beaches not found all along the coast?&#xA;If not beaches,  what else can be found along the coast. &lt;/p&gt;&#xA;" OwnerUserId="13714" LastEditorUserId="13714" LastEditDate="2018-08-30T14:14:03.747" LastActivityDate="2018-08-30T17:15:43.377" Title="Are beaches found all along the coast? If not, what is required for them to be formed?" Tags="|ocean|coastal|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14982" PostTypeId="2" ParentId="14980" CreationDate="2018-08-30T17:15:43.377" Score="3" Body="&lt;p&gt;Not all coastlines have beaches. Some have cliffs, such the &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Australian_Bight&quot; rel=&quot;nofollow noreferrer&quot;&gt;Great Australian Bight&lt;/a&gt;, which forms a significant part of the southern coast of Australia. The limestone cliff portion of &lt;a href=&quot;https://www.britannica.com/place/Great-Australian-Bight&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Bight&lt;/a&gt; is over 1000 km in length and between 60 and 120 metres in height.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly, in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Otway_National_Park&quot; rel=&quot;nofollow noreferrer&quot;&gt;Otway&lt;/a&gt; region of the Australian state of Victoria forested hills form the coast in regions. As can be seen when travelling along the &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Ocean_Road&quot; rel=&quot;nofollow noreferrer&quot;&gt;Great Ocean Road&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Western Australia, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Zuytdorp_Cliffs&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zuytdorp Cliffs&lt;/a&gt; form 150 km of the coast. Like the Great Australian Bight, these cliffs are formed formed of ancient limestone. Some of the cliffs rise to &lt;a href=&quot;https://www.australiascoralcoast.com/destination/steep-point-and-zuytdorp-cliffs&quot; rel=&quot;nofollow noreferrer&quot;&gt;170 m&lt;/a&gt; in height.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, many of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Fjord&quot; rel=&quot;nofollow noreferrer&quot;&gt;fjords&lt;/a&gt; of Norway and &lt;a href=&quot;https://en.wikipedia.org/wiki/Fiordland&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fiordland in New Zealand&lt;/a&gt; also have coastlines without beaches, where hills &amp;amp; ranges meet the sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Beach&quot; rel=&quot;nofollow noreferrer&quot;&gt;Beaches&lt;/a&gt; are only formed when land gently slopes into the sea. They &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;typically occur in areas along the coast where wave or current action deposits and reworks sediments.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The sediments can be sand, pebbles, or biological materials such as shells and coralline algae.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to forming on ocean coastlines, some beach for on lake shores.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-08-30T17:15:43.377" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14983" PostTypeId="2" ParentId="14936" CreationDate="2018-08-31T07:30:01.970" Score="2" Body="&lt;p&gt;Yes, it's called glacial rebound. Some areas of the globe are still responding to the disappearance of the ice of the last ice age. A well known example of this are the raised beaches in the northern Baltic, where the crust is rising due the melting of the ice sheet that covered Scandinavia.&lt;/p&gt;&#xA;" OwnerUserId="13736" LastActivityDate="2018-08-31T07:30:01.970" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14985" PostTypeId="1" CreationDate="2018-08-31T09:56:25.757" Score="8" ViewCount="406" Body="&lt;p&gt;I read that we are facing the very real possibility of Earth's average temperature rising by more that 2 degrees Celsius by the end of the century.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I understand our planet is constantly loosing its atmosphere and oceans to space but at a very microscopic and thus safe levels. Will Global warming lead to accelerated evaporation converting Earth into a dead waterless desert in the observable future?&lt;/p&gt;&#xA;" OwnerUserId="13739" LastEditorUserId="11430" LastEditDate="2018-09-21T08:29:25.333" LastActivityDate="2018-11-05T16:46:17.810" Title="Does Earth risk losing its oceans to space due to global warming?" Tags="|climate-change|water|thermodynamics|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="14986" PostTypeId="2" ParentId="14642" CreationDate="2018-08-31T14:04:19.200" Score="2" Body="&lt;p&gt;This is a broad question, the best way to compare the models is to go through the manuals and compare the process algorithms to see how the various hydrologic processes are handled. There are other considerations as well, including:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;what environment/watershed are you modelling? How large, how urbanized, what type of soils/environment/precipitation vs evapotranspiration, how important are snow processes, etc., and compare that to what the models were made for&lt;/li&gt;&#xA;&lt;li&gt;what is the purpose of your modelling? Your choice of model will be different if you are looking at water balance vs flood forecasting vs water quality estimates&lt;/li&gt;&#xA;&lt;li&gt;what data do you have available? Some models are more intensive with data requirements than others, and if you only have daily precipitation and temperature (as is typical) than that will restrict some model types&lt;/li&gt;&#xA;&lt;li&gt;what level of accuracy do you need? The timestep options in the models will make a difference&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;That being said, generally my understanding from a broad perspective is that:&#xA;- HSPF is a more detailed hydrologic model with larger data requirements for input forcings, and has also a more comprehensive process library with respect to water quality&#xA;- SWAT as you said was developed for agricultural regions, has less strict data requirements and also some ability to model water quality parameters (though less detailed than HSPF)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Depending on the purpose of your modelling, you may want to consider:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;starting with a simpler model, such as GR4J, just to get the ball rolling before investing more time into complex models, particularly if just need simple answers from the model&lt;/li&gt;&#xA;&lt;li&gt;using a flexible model where the processes can be modified on the fly and you are not committed to a particular set of algorithms when you choose the modelling framework, e.g. the &lt;a href=&quot;http://raven.uwaterloo.ca/Main.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Raven hydrologic modelling framework&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Hope that helps!&lt;/p&gt;&#xA;" OwnerUserId="8440" LastActivityDate="2018-08-31T14:04:19.200" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14987" PostTypeId="1" AcceptedAnswerId="14998" CreationDate="2018-08-31T15:04:07.620" Score="4" ViewCount="123" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pOj7n.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pOj7n.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lat., long.38.47491, 43.48882, in the vicinity of Van in Turkey&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I saw this when hiking. I want to know what it is and what are the dangers it poses. Lots of people hike that area in spring and summer, villagers collect edible plants in the area and graze livestock there.&lt;/p&gt;&#xA;" OwnerUserId="13741" LastEditorUserId="2470" LastEditDate="2018-08-31T17:03:39.563" LastActivityDate="2018-09-01T11:38:04.030" Title="What is this? A sinkhole?" Tags="|geology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14988" PostTypeId="1" CreationDate="2018-08-31T17:22:02.220" Score="3" ViewCount="162" Body="&lt;p&gt;Because in both the cases, the warm water/ increase in temperature is seen on the east side of Africa.  Does not they mean that they carry rain bearing clouds from east of Africa to India, resulting in flood like situation in India. &#xA;Do they differ in any other way,  please let me know if I got them wrong? &lt;/p&gt;&#xA;" OwnerUserId="13714" LastActivityDate="2018-08-31T17:42:29.980" Title="Are La-Nina and positive Indian Ocean dipole similar?" Tags="|climate|ocean|monsoon|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14989" PostTypeId="2" ParentId="14987" CreationDate="2018-08-31T17:30:52.153" Score="2" Body="&lt;p&gt;Given there is no raised rim around the hole, it is not meteorite crater.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is difficult to be certain given the perspective view in the picture, but it appears to be sink hole, also known as a subsidence hole. More pictures of the area &amp;amp; even an aerial view would help significantly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the region has a history of underground mining, the hole may be due to the collapse of underground openings resulting in subsidence on the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the is no history of mining in the region then an opening may have been created underground, by subterranean water sources and the surface material has subsided or sunk into the hole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another possibility is that the hole is a bomb crater produced by the military. This could occur if the site was used as a bombing range by the Turkish air force. Also, given the proximity of the area to Kurdish regions, another possibility is that a bomb could have been dropped during a battle with Kurdish or similar forces.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-08-31T17:30:52.153" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="14990" PostTypeId="2" ParentId="14988" CreationDate="2018-08-31T17:42:29.980" Score="1" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Indian_Ocean_Dipole&quot; rel=&quot;nofollow noreferrer&quot;&gt;Indian Ocean dipole&lt;/a&gt; is essentially a measure of the difference in sea surface temperatures between the western and eastern Indian Ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://oceanservice.noaa.gov/facts/ninonina.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;El Nino and La Nina&lt;/a&gt; are the opposite phases of the El Nino Southern Oscillation cycle that occurs in the Pacific Ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only similarity with the Indian Ocean dipole, is that the difference between the sea surface temperature between the central western Pacific Ocean &amp;amp; central eastern Pacific Ocean are measured.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-08-31T17:42:29.980" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14992" PostTypeId="1" AcceptedAnswerId="14994" CreationDate="2018-09-01T02:01:17.270" Score="3" ViewCount="72" Body="&lt;p&gt;Why do the meteorologists still cannot predict if a day would be rainy or cloudy or blizzardy even on the beginning of the day sometimes?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My life circles around weather and an avid weather watcher.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And I noticed the computers still are not advanced enough to get all the variables to predict the weather accurately. The weathermen and women still read the probabilities. For example, there is a 70% chance of rain. I take the umbrella outside and there is no rain. Then the prediction is the day would be cloudy. But then there is rain. I am not saying it happens most of the time. But it happens sometimes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do we need a quantum computer then with qubits? Because it can hold a myriad of variables and consider them in the calculation of the weather. &lt;/p&gt;&#xA;" OwnerDisplayName="user13744" LastActivityDate="2018-09-01T03:29:40.650" Title="Why can't the meteorologists predict for sure if the day would be rainy even on the beginning of the day sometimes?" Tags="|meteorology|predictability|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14993" PostTypeId="1" AcceptedAnswerId="15010" CreationDate="2018-09-01T02:06:35.627" Score="7" ViewCount="2799" Body="&lt;p&gt;I found this crumbly rock embedded in the channel walls of a small creek in Everett, WA, USA. (North Creek that flows through McCollum Park.)  If possible, I'd like to know how the rock formed... what process leads to its formation? It's the crumbly part that I'm most curious about.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The shape is ellipsoid, abut 8 cm on a side:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/EWhqS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EWhqS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The entire thing is made of different types of 1-3 millimeter (or so) sized crystals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/14D3s.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/14D3s.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would have called it granite or some other relative; to my non-expert eye, I see feldspars, some quartz, and mica. Except that it's very crumbly. Here's a video that shows better the texture and how loosely-bound the crystals are to each other. You can flake them all off with your hand.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://youtu.be/FAMZ0do98yU&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://youtu.be/FAMZ0do98yU&lt;/a&gt; &amp;lt;-- Very useful video&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;How is this formed? Are the minerals dissolved in the creek and they happen to have found a nice place to precipitate out? (If so, what would happen as time goes on? Would the rock grow larger with same crystal size, or larger crystal size but same overall rock size?)&lt;/p&gt;&#xA;" OwnerUserId="13743" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T14:14:37.307" LastActivityDate="2019-08-29T14:14:37.307" Title="How is this crumbly crystal-rich rock formed?" Tags="|rocks|weathering|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14994" PostTypeId="2" ParentId="14992" CreationDate="2018-09-01T03:29:40.650" Score="2" Body="&lt;p&gt;The probability of precipitation (POP) has to take into account the areal coverage of some region, e.g. the broadcast market of your local TV station, but perhaps the size of your local county or region.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because of this the POP is calculated as &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$\mathrm{POP} = C \times A$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where $C$ is the confidence it will rain somewhere within the forecast region and $A$ how much of the area will experience the precipitation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So a 100% chance of rain means it is going to rain in the entire forecast region and they are confident that it will rain.  That is a high bar, as spatial coverage of storms is often localized.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, if one storm is going to track through your city and its path is only going to cover 15% of the area, even if we are 100% sure it is going to happen, that still only yields a &quot;15% chance of rain&quot;.  This is because people living in that area where the storm goes though will get rained on, but the other people will not.  This also helps average out temporal and spatial errors in the forecast.&lt;/p&gt;&#xA;" OwnerUserId="64" LastActivityDate="2018-09-01T03:29:40.650" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="14995" PostTypeId="2" ParentId="14993" CreationDate="2018-09-01T05:56:20.947" Score="7" Body="&lt;p&gt;Yes, this is a granite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's hard to know exactly which one. A &lt;a href=&quot;http://www.dnr.wa.gov/publications/ger_ofr73-1_geology_south_snohomish_co_pt2.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;geological map&lt;/a&gt; of the area shows the bedrock to be sedimentary rocks, so this piece of granite was transported in the creek from far away (but not too far, otherwise it will crumble completely).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we go further east, for example with this &lt;a href=&quot;https://pubs.er.usgs.gov/publication/i1963&quot; rel=&quot;nofollow noreferrer&quot;&gt;geological map&lt;/a&gt;, we find that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;To the east, the higher-grade terrane is mostly the Chiwaukum Schist and related gneisses of the Nason terrane and invading mid-Cretaceous stitching plutons&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Rocks of the Cascade magmatic arc are mostly represented by Miocene and Oligocene plutons, including the Grotto, Snoqualmie, and Index batholiths. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So it could be a very poor example of a high-grade granitic composition gneiss, or it could be a granite from Cretaceous, Miocene or Oligocene times. Any more information than that would require someone to study the rock in detail.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2018-09-03T01:42:34.033" LastActivityDate="2018-09-03T01:42:34.033" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="14997" PostTypeId="1" AcceptedAnswerId="15014" CreationDate="2018-09-01T10:11:02.577" Score="2" ViewCount="2494" Body="&lt;p&gt;What is the difference between physiography &amp;amp; topography? I can't understand the context in which to use both. Please explain by giving suitable examples. &lt;/p&gt;&#xA;" OwnerUserId="13610" LastActivityDate="2018-09-03T00:07:25.443" Title="Topography &amp; physiography" Tags="|geomorphology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="14998" PostTypeId="2" ParentId="14987" CreationDate="2018-09-01T11:38:04.030" Score="2" Body="&lt;p&gt;This is most likely a small &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Slump_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;slump&lt;/a&gt; scar modified by later erosion. If you look at the feature from a different angle &lt;a href=&quot;https://earth.app.goo.gl/?apn=com.google.earth&amp;amp;ibi=com.google.b612&amp;amp;isi=293622097&amp;amp;ius=googleearth&amp;amp;link=https%3a%2f%2fearth.google.com%2fweb%2f%4038.47527282,43.48863699,2609.19707642a,183.06362143d,35y,155.54596085h,79.62697511t,0r&quot; rel=&quot;nofollow noreferrer&quot;&gt;in Google Earth&lt;/a&gt;, you will see that it's not even circular.  It's more of a teardrop-ey crescent Moon shape, with the concave part downslope from the convex part. The bottom edge and top edge used to match up before the slide.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastActivityDate="2018-09-01T11:38:04.030" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15000" PostTypeId="1" CreationDate="2018-09-01T17:48:17.557" Score="1" ViewCount="40" Body="&lt;p&gt;I am not an expert in geography. In fact, I know almost nothing about geography. This question in fact concerns a math problem: I have been assigned to construct an analytic description, i.e. to find a functions which takes in coordinates on the earth as input, and splits out the daylight hours at that position, during the time of winter solstice. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Right now I have been successful in finding the correct function. The problem comes with interpretation. With my solution I come to the conclusion that, when the position is very close to the Arctic and Antarctic circles ( but have yet reached within ), my solution says that I should expect some very rapid, waterfall like drop in the day light hours. Mathematically speaking this means that the derivative of my function is infinite at the boundary of the Arctic and Antarctic circles. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I find this hard to believe. If this is true, then based on my observations from the map, would say things like, a small island on the boundary of the Arctic circle may still have some good day light, but once you enter the circles you get no day light at all.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course the small should be relatively different. In my calculation I just assumed the earth to be a unit ball with radius one, which certainly isn't the case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my question is, is this actually true, or possibly true in any sense?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks in advance!&lt;/p&gt;&#xA;" OwnerUserId="13750" LastActivityDate="2018-09-01T17:48:17.557" Title="Increse/decrease in day light hours at locations very close to the Arctic and Antarctic circles" Tags="|geography|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15002" PostTypeId="1" AcceptedAnswerId="15003" CreationDate="2018-09-01T17:50:58.597" Score="1" ViewCount="310" Body="&lt;p&gt;Randomly oriented fossils may indicate an autochthonous deposit whereas parallelly oriented fossils indicate directionality of flow. How?&lt;/p&gt;&#xA;" OwnerUserId="13748" LastEditorUserId="6465" LastEditDate="2018-09-04T16:53:22.663" LastActivityDate="2018-09-04T16:53:22.663" Title="In what way does the orientation of fossils help? What can we infer from that?" Tags="|paleontology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15003" PostTypeId="2" ParentId="15002" CreationDate="2018-09-01T18:23:18.167" Score="3" Body="&lt;p&gt;Lots of bones are long and thin and fairly heavy, to turn them all in the same direction water flow has to be fairly fast, we see the same thing today. fast flowing water turns bones and logs to present the least drag. This is important because it was one of the first ways used to establish bones whether had been moved by the environment after death. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2018-09-01T18:23:18.167" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15004" PostTypeId="2" ParentId="8086" CreationDate="2018-09-02T00:43:34.113" Score="0" Body="&lt;p&gt;Using Python, the best solution I've been able to find is pyresample. See this &lt;a href=&quot;http://earthpy.org/interpolation_between_grids_with_pyresample.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;blog post&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="13755" LastActivityDate="2018-09-02T00:43:34.113" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15006" PostTypeId="2" ParentId="5255" CreationDate="2018-09-02T06:23:15.937" Score="1" Body="&lt;p&gt;I had the exact same experience as the original poster, just this evening Sept 1, 2018, coincidentally right by Wittman Airport in Oshkosh.  It's flat without trees across the EAA grounds there, so I could see to the horizon. There were lightning strikes going on almost directly south, and the lightning was colored orange by the humid air and distance.  I seriously underestimated the distance of the storms; I thought they were between Fond Du Lac and Milwaukee.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I got home, I got on the computer and looked at weather radar.  To my amazement, the storm line was in northern Illinois, a little bit south of Rockford, a good 150 miles (240 km) away as the crow flies.  That had to be some huge storms and cloudtop to ground type lightning to be visible so far away.  &lt;/p&gt;&#xA;" OwnerUserId="13757" LastEditorUserId="725" LastEditDate="2018-09-02T07:07:30.290" LastActivityDate="2018-09-02T07:07:30.290" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15007" PostTypeId="2" ParentId="15002" CreationDate="2018-09-02T12:58:36.533" Score="0" Body="&lt;p&gt;John is totally right. I just want to add one more information: most fossils have one side or end, which is heavier than the other (for example look at belemnites). The heavy end will point to the direction the current comes from. The lighter end will freely orient in the direction the current goes to. Paleontologists call this anchored deposition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Autochthonous deposits are autochthonous, because they show no signs of transportation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You shouldn't differentiate between &quot;current and autochthonous&quot;, but between autochthonous and allochthonous. Latter indicates transportation of the fossil away from its original deposition place. Even this transportation might me chaotic and not perfectly oriented in one direction, depending on the flow rate and the fact &lt;em&gt;what&lt;/em&gt; flows there (water, debris).&lt;/p&gt;&#xA;" OwnerUserId="13398" LastActivityDate="2018-09-02T12:58:36.533" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15008" PostTypeId="1" AcceptedAnswerId="15019" CreationDate="2018-09-02T14:32:39.013" Score="4" ViewCount="117" Body="&lt;p&gt;I am listening to a song about volcanoes. It is called &quot;Pyroclastic Annihilation&quot; performed by a brutal deth/thrash metal band called &quot;Demolition Hammer&quot;. It is from their album &quot;Epidemic of Violence&quot; released in 1992. The song is:&#xA;&lt;a href=&quot;https://www.youtube.com/watch?v=S_7qqsVioxo&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=S_7qqsVioxo&lt;/a&gt;&#xA;the full lyrics can be found here:&#xA;&lt;a href=&quot;https://genius.com/Demolition-hammer-pyroclastic-annihilation-lyrics&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://genius.com/Demolition-hammer-pyroclastic-annihilation-lyrics&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have come across a term I do not understand.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Molten debris&lt;br/&gt;&#xA;  Volcanic ash&lt;br/&gt;&#xA;  Seas of boiling mud&lt;br/&gt;&#xA;  Subrelluric forces exploding violently&lt;br/&gt;&#xA;  Pyroclastic matter intense velocity&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Is the word &quot;Subrelluric&quot; a geological term? If yes what does it mean exactly? What are Subrelluric forces? What do they do amidst a volcanic eruption? I couldn't find anything on the web. Perhaps this is an extremely advance term not usually used in the public world?&lt;/p&gt;&#xA;" OwnerUserId="12349" LastEditorUserId="12349" LastEditDate="2018-09-03T09:03:30.207" LastActivityDate="2018-09-03T16:36:14.527" Title="Subrelluric forces in a volcanic eruption" Tags="|geology|volcanology|terminology|volcanic-eruption|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15010" PostTypeId="2" ParentId="14993" CreationDate="2018-09-02T15:14:52.103" Score="8" Body="&lt;p&gt;Even rocks that have lasted for billions of years decompose when exposed to Earth's weather.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What you have is indeed granite, but a somewhat &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Decomposed_granite&quot; rel=&quot;nofollow noreferrer&quot;&gt;decomposed granite&lt;/a&gt;, which is treated by geologists differently from the intact, solid stuff.  The &quot;crumbly bits&quot; have their own &#xA;name: &lt;strong&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Grus_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;grus&lt;/a&gt;&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Granite is made of crystals of different minerals  (mostly feldspar and quartz) that grew into each other as the parent magma cooled. The final rock is solid because of the irregular way the crystals fit into each other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Granite weathers in several different ways. Cracks can form from hot and cold cycles. However, &lt;a href=&quot;https://www.americangeosciences.org/education/k5geosource/content/rocks/what-is-chemical-weathering&quot; rel=&quot;nofollow noreferrer&quot;&gt;chemical weathering&lt;/a&gt; is the principal way granite becomes crumbly.  &lt;a href=&quot;https://en.wikipedia.org/wiki/Acid_rain&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rain frequently picks up some acidity&lt;/a&gt; from the atmosphere, and infiltrates the granite. This acidic rain reacts with the feldspar and mica to produce clay minerals, primarily &lt;a href=&quot;https://en.wikipedia.org/wiki/Kaolinite&quot; rel=&quot;nofollow noreferrer&quot;&gt;kaolinite&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This in turn makes it easier for water to get in the granite, and combined with heat cycles the process accelerates.&#xA;As a result, the joints between the crystals loosen up, producing rock in the same condition as your rock. &lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2018-09-04T23:05:53.583" LastActivityDate="2018-09-04T23:05:53.583" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15011" PostTypeId="1" AcceptedAnswerId="16090" CreationDate="2018-09-02T19:12:48.040" Score="5" ViewCount="107" Body="&lt;p&gt;The earth's ocean tides are primarily driven by the moon, but also by the sun. The relative strengths of the related tidal constituents varies from place to place across the globe. But what is the proportion of the energy entering the global system from each?&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-01-29T04:28:25.890" Title="What proportion of the energy input to the ocean tide system comes from the sun?" Tags="|tides|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15012" PostTypeId="1" CreationDate="2018-09-02T21:25:49.123" Score="2" ViewCount="443" Body="&lt;p&gt;I found this weird fossil rock and I am wondering if anybody could help identify what could have made the imprint in it or what kind of rock it is?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fYx73.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fYx73.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kRPD2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kRPD2.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13762" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T14:14:47.553" LastActivityDate="2019-08-29T14:14:47.553" Title="What is this strange fossil I found?" Tags="|fossils|paleontology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15013" PostTypeId="2" ParentId="15012" CreationDate="2018-09-02T21:36:12.740" Score="6" Body="&lt;p&gt;Looks like a sand dollar fossil.  Note the pentagonal shape in the middle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7c3wf.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7c3wf.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.fossilera.com/fossils/3-2-fossil-sand-dollar-dendraster-cluster-california&quot; rel=&quot;noreferrer&quot;&gt;fossilera.com&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2018-09-02T21:36:12.740" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="15014" PostTypeId="2" ParentId="14997" CreationDate="2018-09-03T00:07:25.443" Score="4" Body="&lt;p&gt;Physiography explains the physical characteristics of the area more generally describing the physical processes or forces that formed the landscape, while topography describes particular features, typically associated with elevations. For example in geomorphology (as your post is tagged) the physiography of Canadian prairies may describe deep fertile soils, ancient lake bed remnants, multiple sloughs or ditches that fill with water, etc. The topography would describe the extreme flatness with many depressions in the landscape. In practice, physiography is quite broad and topography refers to elevation data (I.e. a topographic map would have elevation points or contours). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take a look here at &lt;a href=&quot;https://wikidiff.com/topography/physiography&quot; rel=&quot;nofollow noreferrer&quot;&gt;WikiDiff&lt;/a&gt; as well.&lt;/p&gt;&#xA;" OwnerUserId="8440" LastActivityDate="2018-09-03T00:07:25.443" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15015" PostTypeId="2" ParentId="15008" CreationDate="2018-09-03T06:03:25.013" Score="3" Body="&lt;p&gt;This term does not exist in volcanology. I can’t even think of a similar sounding term that can be misheard in the song, or misheard by the authors and then put in the song.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It’s possible it exists in a different language but I am not familiar with any options.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sounds like your best bet would be to ask the band.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-09-03T06:03:25.013" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15016" PostTypeId="2" ParentId="6527" CreationDate="2018-09-03T12:19:20.707" Score="0" Body="&lt;p&gt;The latent heat issue is indeed a big one. The total latent heat from melting $15,000$ cubic km of ice (this $15,000$ is an arbitrary number, but you could take it to mean a very large amount of melting) is $15000 \cdot 997\frac{\rm kg}{\rm m^3} $ &lt;sub&gt;&lt;sup&gt;(the density of water)&lt;/sup&gt;&lt;/sub&gt; $ \cdot \, 334\frac{\rm kJ}{\rm kg}\,$ &lt;sub&gt;&lt;sup&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Enthalpy_of_fusion&quot; rel=&quot;nofollow noreferrer&quot;&gt;(the enthalpy of fusion)&lt;/a&gt;&lt;/sup&gt;&lt;/sub&gt; $ \cdot \frac {1000 \, \rm J}{1 \, \rm kJ} \cdot  \frac{10^9 \, \rm m^3}{1 \, \rm km^3}$ = $4.995\times 10^{21}$ Joules&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Compare that to the total energy imbalance for the Earth of &lt;a href=&quot;https://www.giss.nasa.gov/research/briefs/hansen_16/&quot; rel=&quot;nofollow noreferrer&quot;&gt;$0.58 \frac{\rm Watts}{\rm m^2}$&lt;/a&gt; (You can replace $0.58$ with $1.17$ if you think that is the real imbalance). For the whole surface area, that &lt;a href=&quot;http://www.wolframalpha.com/input/?i=0.58%20W%2Fm%5E2%20*%20SetPrecision%5Bsurface%20area%20of%20earth,3%5D&quot; rel=&quot;nofollow noreferrer&quot;&gt;comes to&lt;/a&gt; $2.96 \times 10^{14}$ Watts.  Now, over a year, that energy imbalance is $2.96 \times 10^{14} \cdot \frac{365\, \rm days}{1\, \rm yr} \cdot \frac{24\, \rm hrs}{1\, \rm day} \cdot \frac{60\, \rm min}{1\, \rm hr} \cdot \frac{60\, \rm sec}{1\, \rm min}$. That's $9.33 \times 10^{21} J$. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, one fair ratio of latent heat to energy imbalance is $4.995:9.33$. Of course, this assumes the $15,000$ cubic km of ice is melted in one year. On the other hand, the relevant number for energy imbalance is also overestimated. That's because the amount of heat that is actually available to heat the earth is a tiny fraction of the imbalance (The exact fraction depends on the model you use). Regardless, latent heat is a major problem for further heating...scarily so. &lt;/p&gt;&#xA;" OwnerUserId="13764" LastEditorUserId="6298" LastEditDate="2018-09-04T17:26:53.860" LastActivityDate="2018-09-04T17:26:53.860" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15017" PostTypeId="2" ParentId="14306" CreationDate="2018-09-03T12:59:04.253" Score="4" Body="&lt;p&gt;The other answers are correct that you need to know the soil depth to convert from mass units (kg m-2) to volumetric units (m3 m-3).  However, when comparing these variables you should also be aware that satellite soil moisture is typically measured only over the top few centimetres of soil. Total column soil moisture from a climate model will typically be the sum over several metres, so the dynamics of these two variables are likely to be quite different (contrast the red and light blue lines in the upper plot).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's more common to compare satellite data with top-layer soil moisture and even then to normalize each dataset in some way, e.g, &lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$NWI = \frac{SM - SM_{min}}{SM_{max} - SM_{min}}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;or as normalised anomalies,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;$$NWI = (SM - \overline{SM}) / \sigma_{SM}$$&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've used the latter to normalize the lower plot.  Normalization gets around the units problem, but doesn't get around the fact that you're comparing physically different quantities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qp8vK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qp8vK.png&quot; alt=&quot;Daily soil moisture&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2018-09-03T12:59:04.253" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15019" PostTypeId="2" ParentId="15008" CreationDate="2018-09-03T16:36:14.527" Score="3" Body="&lt;p&gt;I believe what you heard is “subtelluric” where &lt;a href=&quot;https://en.wikipedia.org/wiki/Telluric&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;telluric&quot;&gt;telluric&lt;/a&gt; means “of the earth”.&lt;/p&gt;&#xA;" OwnerUserId="813" LastActivityDate="2018-09-03T16:36:14.527" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15023" PostTypeId="2" ParentId="6527" CreationDate="2018-09-04T05:07:46.350" Score="4" Body="&lt;p&gt;This IPCC graph (&lt;a href=&quot;https://johncarlosbaez.wordpress.com/2014/04/11/what-does-the-new-ipcc-report-say-about-climate-change-part-4/&quot; rel=&quot;nofollow noreferrer&quot;&gt;discussed here&lt;/a&gt;) shows the amounts of heat going into oceans, atmosphere, land and ice melting.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/E62Bc.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/E62Bc.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Plot of energy accumulation in zettajoules within distinct components of Earth’s climate system relative to 1971 and from 1971–2010 unless otherwise indicated. Ocean warming (heat content change) dominates, with the upper ocean (light blue, above 700 m) contributing more than the deep ocean (dark blue, below 700 m; including below 2000 m estimates starting from 1992). Ice melt (light grey; for glaciers and ice caps, Greenland and Antarctic ice sheet estimates starting from 1992, and Arctic sea ice estimate from 1979–2008); continental (land) warming (orange); and atmospheric warming (purple; estimate starting from 1979) make smaller contributions. Uncertainty in the ocean estimate also dominates the total uncertainty (dot-dashed lines about the error from all five components at 90% confidence intervals).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-09-04T11:35:11.893" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15024" PostTypeId="2" ParentId="12291" CreationDate="2018-09-04T07:35:39.253" Score="6" Body="&lt;p&gt;First of all, a plateau as an area of flat topography which stands at higher elevation than the surrounding region; it does not need to be at high elevation in absolute terms. Indeed, there are plateaux below sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are several different processes at the origin of the plateaux in the map you link.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some, such as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Deccan_Plateau&quot; rel=&quot;noreferrer&quot;&gt;Deccan&lt;/a&gt; and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Columbia_Plateau_(ecoregion)&quot; rel=&quot;noreferrer&quot;&gt;Columbia&lt;/a&gt; plateau, are the results of infill of volcanic rocks in an accomodation space during voluminous volcanic eruptions, called &quot;flood basalts&quot;. These flood basalts effectively flow into topographic depressions, thus flattening the topography and resulting in a plateau.&#xA;Note that there are also &lt;a href=&quot;https://en.wikipedia.org/wiki/Oceanic_plateau&quot; rel=&quot;noreferrer&quot;&gt;oceanic plateaux&lt;/a&gt; which are formed by large magma outpours- they are usually below sea level. Examples of this are the Caribbean Oceanic Plateau and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ontong_Java_Plateau&quot; rel=&quot;noreferrer&quot;&gt;Ontong-Java&lt;/a&gt; plateau.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other plateaux such as the Altiplano and Loess plateau appear to be a result of basin infill by mainly sedimentary processes, either by water or wind transport. Past erosion removed material from topographic highs and dumped it in topographic lows, thus flattening out the relief. This is effectively a &lt;a href=&quot;https://en.wikipedia.org/wiki/Peneplain&quot; rel=&quot;noreferrer&quot;&gt;peneplenation&lt;/a&gt; process operating locally.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although the high elevation of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Tibetan_Plateau&quot; rel=&quot;noreferrer&quot;&gt;Tibetan plateau&lt;/a&gt; is undoubtedly due to tectonic uplift, the cause of flat topography appears is likely to reflect relief reduction by combined erosion and deposition as above. It is unclear whether this was an ancient peneplain which was pushed upwards, or a more recent feature. &lt;/p&gt;&#xA;" OwnerUserId="4783" LastActivityDate="2018-09-04T07:35:39.253" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15028" PostTypeId="1" AcceptedAnswerId="15029" CreationDate="2018-09-05T13:57:24.120" Score="7" ViewCount="758" Body="&lt;p&gt;I'm interested in visualizing climate data across the conterminous U.S. to determine regions that I would be interested in living in.  So far, I've pulled in NOAA data, and I've:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;averaged the maximum daily temperature measurements per location&lt;/li&gt;&#xA;&lt;li&gt;averaged the minimum daily temperature measurements per location&lt;/li&gt;&#xA;&lt;li&gt;taken the difference between the average maximum temperature measurements and the average minimum temperature measurements to determine how much weather varies across the year per location&lt;/li&gt;&#xA;&lt;li&gt;pulled precipitation in tenths of mm per location&lt;/li&gt;&#xA;&lt;li&gt;pulled snowfall in mm per location&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;At first, these seemed like &quot;good enough&quot; approximations, but I'm discovering that this approach is somewhat inadequate because it is:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Not appropriately representing swings in daytime-nightime temperatures&lt;/li&gt;&#xA;&lt;li&gt;Not appropriately representing the annual variance in temperatures between locations&lt;/li&gt;&#xA;&lt;li&gt;using averages&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I was initially seeking to discover areas with a high mean temperature, low variance in temperatures annually and daily, and low rainfall.  What metrics could I be using to improve this investigation?  Thanks!&lt;/p&gt;&#xA;" OwnerUserId="13777" LastEditorUserId="13777" LastEditDate="2018-09-05T14:15:45.590" LastActivityDate="2019-06-17T07:23:12.377" Title="What are good metrics to compare climates?" Tags="|meteorology|climate|climatology|statistics|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15029" PostTypeId="2" ParentId="15028" CreationDate="2018-09-05T14:14:22.967" Score="8" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification&quot; rel=&quot;noreferrer&quot;&gt;Köppen climate classification&lt;/a&gt; is a classic metric to classify climates:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:North_America_map_of_K%C3%B6ppen_climate_classification.svg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/7/74/North_America_map_of_K%C3%B6ppen_climate_classification.svg/1024px-North_America_map_of_K%C3%B6ppen_climate_classification.svg.png&quot; alt=&quot;N-America Köppen map&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;em&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:North_America_map_of_K%C3%B6ppen_climate_classification.svg&quot; rel=&quot;noreferrer&quot;&gt;Wikimedia Commons&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;It classifies climates based on the number of months with temperature below and/or above certain thresholds, and on whether rainfall is evenly distributed or concentrated in a particular season.  You will find details on the definitions &lt;a href=&quot;https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification&quot; rel=&quot;noreferrer&quot;&gt;on Wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;An alternative is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Trewartha_climate_classification&quot; rel=&quot;noreferrer&quot;&gt;Trewartha&lt;/a&gt; classification:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:US_trewartha.svg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/7/75/US_trewartha.svg/1211px-US_trewartha.svg.png&quot; alt=&quot;Trewartha map&quot; /&gt;&lt;/a&gt;&#xA;&lt;em&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:US_trewartha.svg&quot; rel=&quot;noreferrer&quot;&gt;Wikimedia Commons&lt;/a&gt;&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Note that the climate you seek may not exist:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;I was initially seeking to discover areas with a high mean temperature, low variance in temperatures annually and daily, and low rainfall.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;A low temperature variance tends to happen in humid climates.  Dry climates tend to have large temperature variances.  A subtropical highland climate may come closest to what you seek, although it's not particularly dry.  In the &lt;a href=&quot;https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification&quot; rel=&quot;noreferrer&quot;&gt;Köppen&lt;/a&gt; classification, this would be &lt;em&gt;Cwb&lt;/em&gt;.  From the Wikipedia article:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Cwb = Subtropical highland climate or Monsoon-influenced temperate oceanic climate; coldest month averaging above 0 °C (32 °F) (or −3 °C (27 °F)), all months with average temperatures below 22 °C (71.6 °F), and at least four months averaging above 10 °C (50 °F). At least ten times as much rain in the wettest month of summer as in the driest month of winter (an alternative definition is 70% or more of average annual precipitation received in the warmest six months).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I don't think any place with Cwb climate exists in the United States.  &lt;a href=&quot;https://en.wikipedia.org/wiki/Quito#Climate&quot; rel=&quot;noreferrer&quot;&gt;Quito&lt;/a&gt; is famous for being the &lt;em&gt;city of eternal spring&lt;/em&gt;, and some areas of Mexico are classified as Cwb, as in &lt;a href=&quot;https://en.wikipedia.org/wiki/Johannesburg&quot; rel=&quot;noreferrer&quot;&gt;Johannesburg&lt;/a&gt;.  I suspect the closest you'll get in the USA will be somewhere not too high, not too low in the Sierra Nevada.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-09-05T14:34:46.683" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15031" PostTypeId="2" ParentId="14993" CreationDate="2018-09-05T22:13:09.683" Score="1" Body="&lt;p&gt;My understanding of why granite decomposes that way is because it's formed under ground and as the over-burnden is removed so is weight and pressure. The granite formations are rounded as the outside layers fall away. We have very few freeze/thaw cycles in Arizona (Phoenix area), and not a lot of rain, but, we have tons and tons of decomposed granite in Arizona. &lt;/p&gt;&#xA;" OwnerUserId="10936" LastActivityDate="2018-09-05T22:13:09.683" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15039" PostTypeId="1" CreationDate="2018-09-06T15:07:59.730" Score="3" ViewCount="574" Body="&lt;p&gt;Immediately below is an illustration of my first/prototype attempt to visualize this, which is further explained after that...&#xA;&lt;a href=&quot;https://i.stack.imgur.com/61cIZ.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/61cIZ.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;What you're looking at is a year-by-year animation of TMAX (daily max temp) data from the USW00094728.dly file (station at Central Park in New York City) openly available at &lt;a href=&quot;ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/daily&quot; rel=&quot;nofollow noreferrer&quot;&gt;ftp://ftp.ncdc.noaa.gov/pub/data/ghcn/daily&lt;/a&gt; (see the readme.txt file in that directory for file format info, etc).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The left-hand-side of each frame is Jan1 TMAX and the right-hand-side is Dec31, whereby each frame represents a full year. And the years are 1870 through 2009, each year displayed for 0.2seconds. Two blank frames signal when the animation repeats. The temp scale is $40^o\mbox{C}$ max, $-10^o\mbox{C}$ min.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, the daily TMAX data in the displayed animation has been smoothed, &lt;em&gt;i.e.&lt;/em&gt;, each day denotes a seven-day average including the three days before and after it. Without that smoothing, it's really, really jumpy/discontinuous.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nevertheless, even with smoothing, there's no TMAX change discernible to the casual observer during the 140 years represented. Of course, with an expected $1$&amp;#150;$2^o$ change on the $40^o$ plot, that might just be too hard to casually notice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So several ideas occurred to me. (a) Maybe subtract out the daily means (averaged over the 140 years), and display a $\sim10^o$ plot, whose higher resolution would make the small delta's more easily observable. (b) The seven-day smoothing, separately over each year, may not be enough since the year-to-year data is still very jumpy. So maybe additionally smooth by averaging the same day over several before-and-after years. But then that may just be too much unjustifiable data massaging.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, the overall question here is: what-to-display/how-to-display-it so that the ~150-year TMAX change is easily visible and easily explainable/understandable to the casual observer. Any average person-in-the-street should just be able to look at it and immediately see what's happening, without any gobbledygook/gibberish technical explanation necessary. Also, a side-question: it took a while to find that noaa ghcn data, which seems terrific. Any equally-good or better openly available datasets around?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&lt;strong&gt;&amp;nbsp;&amp;nbsp;&amp;nbsp;EDIT&lt;br&gt;-----------&lt;/strong&gt;&lt;br&gt;&#xA;Thanks for the comments, @JeopardyTempest and @CamiloRada.&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;JT's &quot;nighttime low&quot; suggestion (TMIN element from ghcn data) is easy to exhibit, just requiring different command-line arguments to exactly the same program (no packages, by the way, all straight C programming, which I mention after noticing &quot;Programmer&quot; in your profile). So I've illustrated that TMIN animation below (scale, etc, identical to TMAX animation above). However, as pretty much expected, still no easily-visualizable change over the 140 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We'll have to try &quot;using anomalies&quot;, quoting CR, and hope for better results. And that's probably a reasonable hope, based on your youtube link, which is pretty much exactly what I think I'd be generating, except with Jan,...,Dec along the x-axis rather than the &quot;circle graph&quot; displayed there. (By the way, while it's easy to interpret that circle graph, I think maybe the average person-in-the-street might more easily recognize the left-to-right months-along-the-x-axis display, which is probably what most people are already more familiar with.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And I'll also take a closer look at that HadCRUT4.4 data used by the youtube's homepage &lt;a href=&quot;http://www.climate-lab-book.ac.uk/2016/spiralling-global-temperatures/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.climate-lab-book.ac.uk/2016/spiralling-global-temperatures/&lt;/a&gt; Google hadn't coughed up that data during the searches I'd tried, and I imagine there's lots more good&amp;amp;interesting stuff I've overlooked.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meanwhile, immediatly below is the TMIN graph suggested by JT. The &quot;anomaly graphs&quot; will be easy to animate after I code the across-the-years data &quot;select&quot;ion (&lt;em&gt;i.e.&lt;/em&gt;, analogous to a relational table) from the ghcn data. That'll take a bit of doing (in my available spare time), and I'll try to post some better temperature-increase visualizations when it's done. JT's more elaborate display suggestions will take a bit more elaborate thinking and doing (moreso on the display side than on the computational side), which I'll try to plan/design as I'm coding the more straightforward &quot;anomaly&quot; stuff. Thanks, again, JT and CR.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7lta5.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7lta5.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13783" LastEditorUserId="13783" LastEditDate="2018-09-07T03:54:21.637" LastActivityDate="2018-09-10T09:31:46.543" Title="How to best visualize temperature increase (due to climate change) using GHCN data?" Tags="|climate|open-data|data-analysis|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15042" PostTypeId="1" AcceptedAnswerId="15047" CreationDate="2018-09-06T20:31:19.063" Score="11" ViewCount="826" Body="&lt;p&gt;Earth's current average global temperature &lt;em&gt;(i.e. including hot deserts and cold polar caps)&lt;/em&gt; is reported be somewhere between 14°C and 16°C &lt;em&gt;(depending on sources and methods)&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This temperature varies on a long-term basis due to climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But does it also vary &lt;em&gt;(substantially)&lt;/em&gt; on a daily basis ?&lt;br&gt;&#xA;I.e. are there &lt;strong&gt;hotter and colder days&lt;/strong&gt; &lt;em&gt;(worldwide)&lt;/em&gt; ?&lt;br&gt;&#xA;&lt;strong&gt;Or&lt;/strong&gt; is it exactly the opposite, namely a &lt;strong&gt;zero-sum game&lt;/strong&gt;: A hotter-than-average day in – say – Australia inevitably goes along with a colder-than-usual day somewhere else on the planet to make up for the difference, so that the global temperature stays the same from one day to the next (because energy is not &lt;em&gt;created&lt;/em&gt; but only &lt;em&gt;transferred&lt;/em&gt; from one region to another) ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an example, below are the relative temperatures (i.e. colder/hotter than expected/average) for 3 Feb 2014. Would the hotter and colder temperature regions balance out (compensate one another), so that the global temperature on 3 feb 2014 is the same as on 2 feb 2014 and 4 feb 2014 ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cbDgA.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cbDgA.jpg&quot; alt=&quot;3feb2014 temperature anomalies&quot;&gt;&lt;/a&gt;&#xA;source: &lt;a href=&quot;https://robertscribbler.com/2014/02/03/arctic-heat-in-winter-february-2-temperature-anomaly-hits-13-f-for-entire-arctic&quot; rel=&quot;noreferrer&quot;&gt;https://robertscribbler.com/2014/02/03/arctic-heat-in-winter-february-2-temperature-anomaly-hits-13-f-for-entire-arctic&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(Please note: The image doesn't exactly illustrate my question, because it doesn't depict the air temperature difference between 3 Feb 2014 and the previous day, but between 3 Feb 2014 and the average for [3 Feb, I assume] 1979-2000. So due to global warming, 3 Feb 2014 was obviously warmer than 3 Feb in previous decades – by 0.45°C to be precise, as the sum of &lt;code&gt;northern hemisphere + southern hemisphere = -0.01°C + 0.45°C = +0.45 °C&lt;/code&gt;. But my question is not about global warming or long term trends, but daily variations. I just couldn't find a similar heat map depicting temperature differences between one day and the next, so I just took this image for illustration purposes, although it doesn't perfectly relate to the question asked.).&lt;/em&gt;&#xA; &lt;br&gt;&#xA;    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As &lt;strong&gt;Earth surface temperatures&lt;/strong&gt; don't necessarily &#xA;correspond to the &lt;strong&gt;air temperature&lt;/strong&gt; (see below), please distinguish both cases in your answer, i.e.:  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Can &lt;em&gt;global average Earth surface temperature&lt;/em&gt; vary from one day to the next ?&lt;/li&gt;&#xA;&lt;li&gt;Can &lt;em&gt;global average air temperature&lt;/em&gt; vary from one day to the next ?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Andreas Schmittner, Oregon State University: &lt;em&gt;&quot;It is not the average temperature of Earth that is reported but the average air temperature near the surface (2 m) of the Earth.&quot;&lt;/em&gt;&lt;br&gt;&#xA;  source: &lt;a href=&quot;https://www.researchgate.net/post/It_it_misleading_to_report_the_average_temperature_of_the_Earth&quot; rel=&quot;noreferrer&quot;&gt;researchgate.net/post/It_it_misleading_to_report_the_average_temperature_of_the_Earth&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I would appreciate if your answer included both a source for your claim AND an explanation (i.e. WHY the global temperature can or cannot vary on a daily basis).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The best answer would include a diagram or table of global average air and Earth surface temperatures for any given month, since this couldn't be argued with.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Example:&lt;pre&gt;&#xA;+-----------+--------------------------------+----------------------+&#xA;|           | avg. global Earth surface temp | avg. global air temp |&#xA;+-----------+--------------------------------+----------------------+&#xA;| 01 Feb 14 |           15.1 °C              |       15.2 °C        |&#xA;| 02 Feb 14 |           15.1 °C              |       15.3 °C        |&#xA;| 03 Feb 14 |           15.1 °C              |       15.7 °C        |&#xA;| 04 Feb 14 |           15.1 °C              |       15.2 °C        |&#xA;| 05 Feb 14 |           15.1 °C              |       15.1 °C        |&#xA;|   ...     |            ...                 |        ...           |&#xA;+-----------+--------------------------------+----------------------+&#xA;&lt;/pre&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;tags: &lt;a href=&quot;/questions/tagged/thermodynamics&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged &amp;#39;thermodynamics&amp;#39;&quot; rel=&quot;tag&quot;&gt;thermodynamics&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="13784" LastEditorUserId="13784" LastEditDate="2018-09-07T04:26:39.667" LastActivityDate="2023-01-31T01:04:20.040" Title="Does the global temperature vary daily (hotter and colder days)?" Tags="|meteorology|atmosphere|geophysics|temperature|planetary-science|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15044" PostTypeId="1" AcceptedAnswerId="15057" CreationDate="2018-09-06T23:55:41.600" Score="5" ViewCount="210" Body="&lt;p&gt;Along the Mississippi River swarms of emerging mayflies have been seen on radar.  The radar and image below are from a July 11, 2017 emergence near LaCrosse, Wisconsin.  On the radar you can see the mayflies emerge from the river and head toward the north.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/78EC1.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/78EC1.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This image was taken in LaCrosse during the emergence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QSYkt.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QSYkt.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Radar &amp;amp; Image Source: &lt;a href=&quot;https://www.weather.gov/arx/mayfly_tracking&quot; rel=&quot;noreferrer&quot;&gt;National Weather Service&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is it possible that other swarms have or can be tracked by weather radar?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2018-09-08T14:16:49.383" Title="Can weather radar be used to track swarms other than mayflies?" Tags="|meteorology|radar|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15046" PostTypeId="2" ParentId="15044" CreationDate="2018-09-07T10:21:34.640" Score="5" Body="&lt;p&gt;Swedish scientists have used the &lt;a href=&quot;http://www2.irf.se/program/paf/?dbfile=MARA_AFP_IRF2&amp;amp;dbsec=IPY&quot; rel=&quot;noreferrer&quot;&gt;Movable Atmospheric Radar for Antarctica&lt;/a&gt; to detect &lt;a href=&quot;https://polarforskningsportalen.se/en/antarctica/expeditions/mara-201213/cruise-reports/mara-moveable-atmospheric-radar-antarctica&quot; rel=&quot;noreferrer&quot;&gt;birds&lt;/a&gt;, which showed up in their radar echo.  I remember that they were talking about teaming up with ornithologists to use what for them is noise (as they're interested in the middle and upper atmosphere) as a signal, but I don't know if they got anywhere with that.  Although not a weather radar, I find it a lovely example of scientific serendipity.&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2018-09-07T10:21:34.640" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15047" PostTypeId="2" ParentId="15042" CreationDate="2018-09-07T12:22:59.143" Score="9" Body="&lt;p&gt;The site &lt;a href=&quot;http://www.karstenhaustein.com/climate.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.karstenhaustein.com/climate.php&lt;/a&gt; comes closer to answering your main question with a daily anomaly graph:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AxSh6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AxSh6.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Indeed it's still not the actual average temperature... and I too was really interested to see if there are annual global fluctuations in global mean temperature itself.  (Surprising how much focus is on anomalies, but how little most sites note the mean temperature itself.)  But eventually I found &lt;a href=&quot;https://www.ncdc.noaa.gov/sotc/global/201701&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA's monthly global climate reports&lt;/a&gt;, and was able to piece together the combined &amp;quot;globally averaged temperature over land and ocean surfaces&amp;quot; for each month and put together this graph:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3ZRv2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3ZRv2.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(One trouble to point out in global totals such as these is that they require the whole globe... so observation of the full far reaches... but we still have a somewhat limited surface observation networks in spots, and each satellite can only see a portion of the globe at one time [and even more, geostationary satellites can't see the Poles], and then all of it is put together by varying data assimilation methods, so there will be some limitations\variation in any global estimates of it [as you can see later down that Karsten Haustein's page in the section comparing CFSR-GFS, NCEP reanalysis, and GISS temperature results])&lt;/p&gt;&#xA;&lt;p&gt;But Karsten's graph above and all the other plots from their site are useful in showing that in real-time and in the past that there are definitely some real oscillations day-to-day... but also that there is indeed quite a bit of overall stability, whereby large regions of hot temperatures will tend to be balanced quite a bit by reduced temperatures elsewhere.&lt;/p&gt;&#xA;&lt;p&gt;This conceptually would seem to make sense to me, as in the end the guiding framework would be that the energy put into the Earth system (by solar radiation) must equal the energy coming out in the long run.  (related example: if you put your food in the oven, it takes in some of the energy, radiating less than it receives, and &lt;a href=&quot;http://www.softschools.com/formulas/physics/heat_transfer_formula/41/&quot; rel=&quot;nofollow noreferrer&quot;&gt;thereby gaining temperature&lt;/a&gt; until it gets up to temp).&lt;br /&gt;&#xA;That balance in itself wouldn't prevent fluctuations in the radiating temperature/energy sent out to space.&lt;/p&gt;&#xA;&lt;p&gt;This is one reason I should expect the global average temperature as a whole does shift some through the year: because water changes temperature more slowly than land, and the NH and SH have different coverage, there should probably be differences/lag in temperature and energy absorption/emission depending upon which portion of the Earth is receiving more sunlight.  Additionally, while the sun's energy is very constant, and the tilt only changes which region receives the energy but not the total amount incoming, there will actually be some overall change in how much energy we get into the lower parts of the atmosphere/to Earth's surface globally day-to-day and over longer periods due to variation in how much &lt;a href=&quot;https://study.com/academy/lesson/albedo-effect-lesson-for-kids.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;snow, cloud cover, and aerosols&lt;/a&gt; absorb/reflect some of the energy before reaching to near the surface.&lt;/p&gt;&#xA;&lt;p&gt;Overall, it seems it would make sense to see a global peak in July (NH summer), when both: more of the &amp;quot;warm Hemisphere&amp;quot; that is receiving increased energy is land to heat faster... and less of the &amp;quot;cold Hemisphere&amp;quot; is land prone to being temporarily covered with very reflective snow.&lt;/p&gt;&#xA;&lt;p&gt;When it comes to any specific layers within the Earth system, be it the surface ground/water, or the atmosphere at 2 meters above the ground, or any other height for that matter, except at depth inside the Earth (which is insulated from those surface energy changes) I'd expect the answer would likely be the same: there is some fluctuation both daily and seasonally.  It's indeed not a zero-sum game because of the variations in the makeup of the globe.  But because the overriding principle is net energy balance of the Earth, those daily/seasonal changes are likely kept to a few degrees tenths of a degree in the short-term and a few degrees Celsius innerannually.&lt;br /&gt;&#xA;The ground/ocean are the primary heat source of air near the ground (air itself doesn't absorb much solar energy).  So generally fluctuations in global average air temperature (at 2 meters) should connect very well to changes in global average near-surface ground/water temperatures... though differences in heat capacity and absorption spectra between air/soil/water/etc likely cause the sizes to be different, and probably small differences in the synchronization as well.  But overall, they should have very similar patterns?&lt;/p&gt;&#xA;&lt;p&gt;But the average anomalies they compute for the globe do their best to take a true global area average it appears.  And while it's true that the same temperature of different substances equates to different amounts of stored energy, I believe radiatively those varying substances would still be &lt;a href=&quot;https://www.e-education.psu.edu/earth103/node/1005&quot; rel=&quot;nofollow noreferrer&quot;&gt;emitting the same amount of energy at equal temperatures&lt;/a&gt;, so such global averages and anomalies of temperatures do have some fair use... and of course are very important to us.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2023-01-31T01:04:20.040" LastActivityDate="2023-01-31T01:04:20.040" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15048" PostTypeId="2" ParentId="15044" CreationDate="2018-09-07T15:51:44.600" Score="5" Body="&lt;p&gt;This &lt;a href=&quot;https://www.citylab.com/environment/2016/06/texas-bats-appear-on-weather-radar/487097/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weather Channel story&lt;/a&gt; gives a lot of things that show up on NWS radar... such as bats&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XWjXD.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XWjXD.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or even &lt;a href=&quot;https://twitter.com/nwsgrandforks/status/1018994074148360193&quot; rel=&quot;nofollow noreferrer&quot;&gt;vehicles on the highway&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fPJEp.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fPJEp.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I believe the conditions typically have to be just right atmospherically to track things in the low atmosphere like this, generally involving beam ducting due to inversions most common near/after dark.  So it's probably unlikely they could be used to do any continual analysis.  But they're definitely neat images!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But indeed radar reflects varyingly depending upon the wavelength it sends out (&lt;a href=&quot;https://data.nodc.noaa.gov/cgi-bin/iso?id=gov.noaa.ncdc:C00708&quot; rel=&quot;nofollow noreferrer&quot;&gt;NWS is about 10 cm&lt;/a&gt;) and the properties of the item it hits, so there are all kinds of current/potential applications for radars, from &lt;a href=&quot;https://en.wikipedia.org/wiki/Ground-penetrating_radar&quot; rel=&quot;nofollow noreferrer&quot;&gt;geology&lt;/a&gt; to &lt;a href=&quot;https://ieeexplore.ieee.org/document/7771668/&quot; rel=&quot;nofollow noreferrer&quot;&gt;medical applications&lt;/a&gt; to &lt;a href=&quot;https://www.smithsonianmag.com/smart-news/us-air-force-builds-new-radar-space-junk-180953855/&quot; rel=&quot;nofollow noreferrer&quot;&gt;tracking space junk&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-09-08T08:01:42.103" LastActivityDate="2018-09-08T08:01:42.103" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15049" PostTypeId="1" AcceptedAnswerId="15235" CreationDate="2018-09-07T17:17:30.793" Score="2" ViewCount="104" Body="&lt;p&gt;Electrodeposition of dissolved minerals in seawater has been used to make coral reef repairs for quite some time. WOLF H. HILBERTZ patented the process and trademarked the name Biorock. I do not have access to IEEE, so I have only been able to read a small portion of this paper:&#xA;&lt;a href=&quot;https://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=9015&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://ieeexplore.ieee.org/xpl/mostRecentIssue.jsp?punumber=9015&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1109/OCEANS.2003.178283&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1109/OCEANS.2003.178283&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The author of the article maintained that this process can build a seawall at a third of the cost of concrete, and it was suitable for building underwater constructions. I have only found references to using this process for repairing coral reefs, but none for construction purposes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the lower cost and material strength claims are valid, it would seem that this process would make it dramatically cheaper to build buildings at depth that could be used to make oceanic research facilities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this a feasible approach to build ocean floor facilities for research or commercial purposes? Does the material formed have low enough porosity to be used as a building exterior wall?&lt;/p&gt;&#xA;" OwnerUserId="2916" LastActivityDate="2018-10-03T21:36:49.520" Title="Would a Biorock formed buiding be suitable for ocean floor research?" Tags="|ocean|oceanography|sea-floor|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15051" PostTypeId="1" AcceptedAnswerId="15058" CreationDate="2018-09-07T12:54:47.953" Score="5" ViewCount="148" Body="&lt;p&gt;It was about 6'o Clock in the Evening. Suddenly I noticed A wierd Cloud in the middle of the sky. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Pffc5.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Pffc5.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JzCmB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JzCmB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there Natural Phenomenon responsible for creating such prefect clouds? &amp;amp; What it is? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;or &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Human activities like Climate Change? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;or&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just a Coincidence ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Im5yG.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Im5yG.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13797" OwnerDisplayName="Shehroz Khan" LastEditorUserId="13797" LastEditDate="2018-09-08T16:15:24.600" LastActivityDate="2018-09-08T16:15:24.600" Title="Appearing of Weird Cornered Cloud in Sky?" Tags="|atmosphere|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15052" PostTypeId="2" ParentId="15051" CreationDate="2018-09-07T18:09:48.590" Score="3" Body="&lt;p&gt;First of all, there is no &quot;non-natural&quot; way to create clouds, unless you count vapor trails from jet aircraft. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Next, you seem to be confusing scattered light from one cloud layer with the local shape of another cloud layer.  The human mind is highly skilled, so to speak, at creating shapes and figures where they don't really exist.  Thus the observation that clouds look like dragons, or fish, or cathedrals.    You've simply photographed a shape that attracted you.  &lt;/p&gt;&#xA;" OwnerUserId="1140" LastActivityDate="2018-09-07T18:09:48.590" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15053" PostTypeId="2" ParentId="2901" CreationDate="2018-09-08T00:02:34.147" Score="0" Body="&lt;p&gt;It's also worth noting that Eluvial soil is moved by water, but not necessarily river water.  The geotech reporting on my hillside property which has no river on it, but experiences significant shift of soil when it rains due to the property's location in a trough (basically a topography-scale gutter on a hillside).  Basically, there's a lot of run-off down the mountainside through the property which shifts the soil on the property over time due to the impact of rain storms.  He referred to the displaced earth as el&lt;/p&gt;&#xA;" OwnerUserId="13792" LastActivityDate="2018-09-08T00:02:34.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15054" PostTypeId="1" AcceptedAnswerId="15059" CreationDate="2018-09-08T01:58:55.327" Score="3" ViewCount="155" Body="&lt;p&gt;Is there anywhere that magnetic ore deposits are strong enough to have a magnetic field that would be stronger then &#xA;Earths' magnetic poles by proximity? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not asking &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13854/where-on-earth-is-the-magnetic-field-intensity-stronger&quot;&gt;Where on Earth is the magnetic field intensity stronger?&lt;/a&gt; In other words where might be a natural place on Earth that would over power a compass and then some? Is there a map of those magnetic field lines minus the Earths' polar magnetic field lines? &lt;/p&gt;&#xA;" OwnerUserId="5052" LastActivityDate="2018-09-10T00:23:58.643" Title="Where on Earth is the highest none polar magnetic fields?" Tags="|geophysics|geomagnetism|mapping|field-measurements|ore|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15055" PostTypeId="2" ParentId="15039" CreationDate="2018-09-08T04:52:22.827" Score="2" Body="&lt;p&gt;Not really an answer, per se. However, as per JT's comment &quot;you somehow need to incorporate the average&quot; (which mirrors my own speculation in the original question), I've incorporated (subtracted out) the means, and that indeed exhibits a easily-seen trend in the graphs. So it's somewhat of an &quot;answer&quot; to that extent, anyway. And I've also created two new types of graphs, illustrated and discussed (all three types) below, along with some additional questions suggested by them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, a static graph of year-by-year, 1870-2009, &amp;nbsp; $T_{MAX}$ deviations from the mean. Each yearly deviation was calculated as a 365/366-day average of daily deviations, i.e., $\frac1{365(or 366)}\sum_{i=jan1}^{dec31}T_i-T^{mean}_i$, &amp;nbsp; where $T^{mean}_i$ is the mean $T$ for that particular day-of-year (averaged over &lt;strong&gt;all&lt;/strong&gt; the years, not yet accounting for CR's comment about pre-1900 or pre-1920 means). And each graph's scale is now $\pm4^oC$. And, again, the leftmost point represents 1870's $T-T^{mean}$, the rightmost point 2009's.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/BhbDK.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BhbDK.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;The above graph has no day-by-day smoothing as discussed previously (we're already averaging over all days, anyway), but it &lt;strong&gt;does&lt;/strong&gt; have a 4-year smoothing, i.e., each $T_i$ in the sum is actually a nine-point moving average of the $T$ for that year and day, along with $T$'s for the same day of the previous and next four years. Without any smoothing at all, it looks like this&#xA;&lt;a href=&quot;https://i.stack.imgur.com/00CJh.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/00CJh.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;So some kind of smoothing seems needed, at least for plots intended for a general audience. I could easily weight each day (e.g., like a normal distribution), assigning the largest weight to the current year's day, but haven't tried any of that yet. Is there any generally-accepted weighting procedure for this kind of data smoothing?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By the way, JT's suggestion to use $T_{MIN}$ actually doesn't seem quite as &quot;monotonic&quot; as the preceding $T_{MAX}$,&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ZLls3.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZLls3.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;So I'll use $T_{MAX}$'s for the animations below...&#xA;&lt;br&gt;&lt;br&gt;&lt;strong&gt;&lt;hr&gt;&lt;hr&gt;&lt;/strong&gt;&lt;br&gt;&lt;br&gt;&#xA;The first type of animation is like the one originally illustrated, but now displaying deviations from the mean, whereby the scale's now $\pm4^oC$. So left-to-right is jan1-to-dec31, with the first frame displaying 1870 and the last frame 2009 (with a few blank frames signalling when the animation repeats). To avoid too-&quot;jittery&quot; animations, nine-point moving average smoothing is used &quot;both ways&quot;, i.e., first $\pm4$days to get the $T$ for a given day within a year, and then $\pm4$years using the same day-of-year's $T$ to get the displayed $T$.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/djl7N.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/djl7N.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;So now (unlike the animations in the original question), the displayed $T$-deviations-from-the-mean start out (in 1870) below the baseline, and end up (in 2009) above it, like we'd expect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But maybe unlike we might expect (at least unlike what I'd expected), watch closely and see that some days of the year seem a bit stubborn about exhibiting higher temps. It's as though climate change has some &quot;national holidays&quot; when it takes a vacation. So that suggested another type of animation to see whether or not that's a real effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This one just takes &quot;slices&quot; from the overall dataset along the other axis. That is, left-to-right is now 1870-to-2009, and the animation has 365 frames, the first for jan1 and the last for dec31 (the extra leap-year day omitted). And smoothing's the same as above.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/DOUkm.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DOUkm.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;So this does seem a bit unexpected to me. Each frame, taken by itself, graphs the year-to-year $T$-deviation for a given day. And each of those graphs looks too continuous. Randomly consider, say, sept28. If it happens to be warmer-than-average one year, you wouldn't expect that fact to have much correlation with whether or not next year's sept28 is also warmer. But the graphs typically pretty long blocks of warmer or cooler years. &lt;/p&gt;&#xA;" OwnerUserId="13783" LastEditorUserId="13783" LastEditDate="2018-09-08T12:01:51.167" LastActivityDate="2018-09-08T12:01:51.167" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="15057" PostTypeId="2" ParentId="15044" CreationDate="2018-09-08T14:16:49.383" Score="6" Body="&lt;p&gt;Bird migration has been studied by Weather radar &lt;a href=&quot;https://www.knmi.nl/kennis-en-datacentrum/project/estimating-bird-migration-using-weather-radar&quot; rel=&quot;noreferrer&quot;&gt;Bird migration study using weather radars &lt;/a&gt; and the monitoring can be visualized here - &lt;a href=&quot;http://www.flysafe-birdtam.eu/profile.php?radar=herwijnen&quot; rel=&quot;noreferrer&quot;&gt;Bird migration density profiles&lt;/a&gt;. A github site &lt;a href=&quot;http://timamp.github.io/&quot; rel=&quot;noreferrer&quot;&gt;Time Integrated Multi altitude Migration Patterns &lt;/a&gt; has been developing algorithms to estimate the density, speed and direction of migration movement at different altitudes around a radar. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastActivityDate="2018-09-08T14:16:49.383" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15058" PostTypeId="2" ParentId="15051" CreationDate="2018-09-08T16:08:51.450" Score="6" Body="&lt;p&gt;The left edge of the cloud is a real edge, irregular and fuzzy as expected. However, the lower sharp edge is just an illusion due to illumination. Just before sunrise or after sunset, the sun can illuminate the upper clouds but not the lower ones. If a cloud happen to be in the limit between illuminated clouds and shaded clouds, it will have its upper side illuminated and the lower one in the shade. That is what you are seeing, the lower edge is not the edge of the cloud, is just the limit of the illuminated part of it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you pay attention you can follow the contrast in illumination even outside of the cloud to the left. Where the illuminated air above the line have a glow not visible in the part under the illuminated part.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-09-08T16:08:51.450" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15059" PostTypeId="2" ParentId="15054" CreationDate="2018-09-09T09:22:26.937" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;In other words where might be a natural place on Earth that would over power a compass and then some&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Just about anywhere where the rocks are rich in iron. This would occur near iron ore, basalt, gabbro, and similar iron-rich rocks. You really don't need a lot of magnetite in the rock for this to move the compass needle. You don't even need magnetite - chromite or pyrrhotite rich rocks may be enough to move the compass needle off.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a common problem when navigating only using a compass in basalt rich areas. A good historical example is that of Tasmania. You can read about it the following article:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://eprints.utas.edu.au/13644/1/1997_Leaman_Magnetic_rst.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Magnetic rocks—their effect on compass use and navigation in Tasmania&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for a map, you're probably looking for a magnetic anomaly map.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://geomag.org/models/wdmam.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's an attempt to make a global&lt;/a&gt; , or this one from &lt;a href=&quot;https://crustal.usgs.gov/projects/namad/&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS&lt;/a&gt;, or this one being &lt;a href=&quot;https://ccgm.org/en/maps/113-carte-des-anomalies-magnetiques-du-monde.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;offered for sale&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2018-09-10T00:23:58.643" LastActivityDate="2018-09-10T00:23:58.643" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15060" PostTypeId="1" AcceptedAnswerId="15065" CreationDate="2018-09-09T17:28:03.530" Score="5" ViewCount="306" Body="&lt;p&gt;I have read that the oldest oceanic plate that we see today is from the Cretaceous period. If so, how do scientists reconstruct plate movements and continental structure pre Cretaceous? And aren't all fossils before Cretaceous lost?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why are we able to deduct geology information pre Cretaceous? And what is the oldest period we are able to gain information from?&lt;/p&gt;&#xA;" OwnerUserId="13800" LastEditorUserId="6467" LastEditDate="2018-09-10T17:59:20.427" LastActivityDate="2018-09-14T00:57:33.857" Title="How do scientists reconstruct pre Cretaceous continent if all plates that are currently left are younger than Cretaceous?" Tags="|plate-tectonics|continent|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="15062" PostTypeId="1" AcceptedAnswerId="15070" CreationDate="2018-09-09T23:04:07.293" Score="3" ViewCount="68" Body="&lt;p&gt;How would a particle other then water travel in a hurricane? At what buoyancy or height would &lt;a href=&quot;https://worldbuilding.stackexchange.com/questions/110241/could-this-bubble-float-with-a-person-inside&quot;&gt;a small air born life preserver&lt;/a&gt; be safe from the ground in a hurricane? How fun would that be?&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2018-09-09T23:09:25.397" LastActivityDate="2018-09-11T04:05:11.933" Title="How would a particle travel in a hurricane?" Tags="|meteorology|wind|tropical-cyclone|natural-disasters|particulates|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15063" PostTypeId="1" CreationDate="2018-09-10T00:24:47.310" Score="5" ViewCount="169" Body="&lt;p&gt;I've always thought of lightning as being either bright white or yellow in color.  However, in the summer I've also seen lightning appear red as so called &quot;heat lightning&quot;.  What I'm wondering is &lt;strong&gt;what colors can lighting be and what causes the different colors&lt;/strong&gt;.  A couple of general answers I've come across on other forums are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Color depends on what is in the atmosphere that the light is&#xA;traveling through&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Color is due to the temperature of the lightning&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;but none of the explanations went into detail of what would cause any individual color.&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastEditorDisplayName="user11318" LastEditDate="2018-09-10T00:39:06.900" LastActivityDate="2018-09-10T00:39:06.900" Title="What colors can lightning be and what causes the different colors?" Tags="|meteorology|lightning|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15064" PostTypeId="1" CreationDate="2018-09-10T00:34:13.337" Score="4" ViewCount="263" Body="&lt;p&gt;Is there a place on Earth that if the wind is blowing its only blowing (here is the twist) in the same direction from the ground to 53 km high?&lt;/p&gt;&#xA;" OwnerUserId="5052" LastActivityDate="2018-09-10T00:34:13.337" Title="Where on Earth does the wind only blow one way?" Tags="|wind|mapping|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15065" PostTypeId="2" ParentId="15060" CreationDate="2018-09-10T02:16:16.017" Score="8" Body="&lt;h2&gt;You forgot about continents&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;First of all, it's necessary to point out the false premise in your question: It is &lt;strong&gt;not true&lt;/strong&gt; that &quot;all plates that are currently left are younger than Cretaceous&quot;.  There is a near-continuous record of rocks stretching all the way back to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hadean&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hadean&lt;/a&gt; Eon 4 billion years ago.  And there are older crystals called &lt;a href=&quot;https://en.wikipedia.org/wiki/Zircon#Radiometric_Dating&quot; rel=&quot;nofollow noreferrer&quot;&gt;zircon&lt;/a&gt;s that are found as inclusions in younger rocks.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The thing is, these rocks are on land, part of &lt;a href=&quot;https://en.wikipedia.org/wiki/Continental_crust&quot; rel=&quot;nofollow noreferrer&quot;&gt;continental crust&lt;/a&gt;. Your question seems to be unaware of the existence of  continental crust. Of course, since you're not currently sitting at the bottom of the ocean, you're on top of continental crust right now. Most of the big tectonic plates are part oceanic and part continental.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Continents have been built up little by little over geological time. Their rocks are a mixed-up jigsaw puzzle of various types and ages. It's the geologist's job to figure out how those pieces fit together.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's just a taste, and it doesn't even show the complexity of the puzzle in North America by a long shot:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/a/a7/North_america_basement_rocks.png&quot; alt=&quot;basement rocks&quot;&gt;&#xA;&lt;em&gt;(courtesy of &lt;a href=&quot;https://www.usgs.gov/information-policies-and-instructions/copyrights-and-credits#copyright&quot; rel=&quot;nofollow noreferrer&quot;&gt;United States Geological Survey&lt;/a&gt;, via &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:North_america_basement_rocks.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikimedia Commons&lt;/a&gt;)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is true that the oceanic plates are mostly destroyed by subduction, but the oceanic crust has to go beneath something, and that's often a continent. Besides, subduction helps make continents grow:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;not all of the rock is subducted: some seafloor sediments are scraped off and piled against continental margins&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The top layers of rock that are subducted melt, and the melted rock bubbles its way up through the overlying crust, producing plutons and volcanic arcs. Sometimes these are on continents (such as the Cascades and Andes) so their rocks directly add mass to them.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;When the volcanoes are out in the ocean, the subduction process pulls them into continents and they get cemented to the edge. Sometimes they form little mini- continents (such as Japan and New Zealand).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The oldest oceanic crust currently at the seafloor is in the eastern Mediterranean. In &lt;a href=&quot;https://www.nature.com/articles/ngeo2784&quot; rel=&quot;nofollow noreferrer&quot;&gt;an article in Nature Geoscience&lt;/a&gt; Roi Granot of Ben-Gurion University of the Negev suggests that the [Herodotus Basin] is a remnant of ancient &lt;a href=&quot;https://en.wikipedia.org/wiki/Tethys_Ocean&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tethys Ocean&lt;/a&gt;, having formed up to 340 Ma during the Early &lt;a href=&quot;https://en.wikipedia.org/wiki/Carboniferous&quot; rel=&quot;nofollow noreferrer&quot;&gt;Carboniferous&lt;/a&gt; period. Most oceanic crust is 200 million years old (Jurassic) or younger.  They're an important part of putting the puzzle together, but as I stated at the beginning of my answer, the geological record is &lt;em&gt;much&lt;/em&gt; older, because of continental rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, there is really old oceanic crust in the form of &lt;a href=&quot;https://en.wikipedia.org/wiki/Ophiolite&quot; rel=&quot;nofollow noreferrer&quot;&gt;ophiolites&lt;/a&gt;, which are bits of oceanic crust that have been incorporated into continents.  Since they're no longer part of the oceanic conveyor belt, some can be quite old. The oldest is about 3.8 billion years old. &lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2018-09-14T00:57:33.857" LastActivityDate="2018-09-14T00:57:33.857" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15066" PostTypeId="2" ParentId="13427" CreationDate="2018-09-10T06:33:59.783" Score="3" Body="&lt;p&gt;Here's an amazing one:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In June 1991 &lt;a href=&quot;https://en.wikipedia.org/wiki/Typhoon_Yunya_(1991)&quot; rel=&quot;nofollow noreferrer&quot;&gt;category 3 Typhoon Yunya&lt;/a&gt; made landfall in central Luzon in the Philippines and gradually weakened as it moved across the island... however as it was near exiting the island... Mount Pinatubo sustained the &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_large_volcanic_eruptions_of_the_20th_century&quot; rel=&quot;nofollow noreferrer&quot;&gt;largest volcanic eruption in our lifetimes&lt;/a&gt; -- almost directly in the center of the storm!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;a href=&quot;http://cimss.ssec.wisc.edu/goes/blog/wp-content/uploads/2016/06/19910612-16_gms4_infrared_Pinatubo_anim.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here is a remarkable satellite loop&lt;/a&gt;&lt;/strong&gt; showing the event unfold. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/st9h4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/st9h4.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;sup&gt;&lt;sub&gt;Screen cap shortly before the event unfolder showing the locations, from &lt;a href=&quot;http://cimss.ssec.wisc.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;UW CIMSS&lt;/a&gt;&lt;/sub&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://cimss.ssec.wisc.edu/goes/blog/archives/21415&quot; rel=&quot;nofollow noreferrer&quot;&gt;CIMSS Satellite Blog has a nice post writing up the event&lt;/a&gt;, along with a collection of additional satellite data.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2018-09-10T06:33:59.783" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15067" PostTypeId="2" ParentId="15039" CreationDate="2018-09-10T08:32:50.780" Score="2" Body="&lt;p&gt;JT's and CR's suggestions in the comments following the &quot;first answer&quot; are incorporated in the gif's below. The new ones that correspond to the previously-displayed ones are a bit more &quot;jittery&quot; than those previous ones -- they had a little bug, as follows. The &quot;baseline mean&quot; for the year-by-year animations, with jan1-dec31 along the x-axis, is the mean/average for each day summed over all the displayed years. But my summing for that mean took place &gt;&gt;after&amp;lt;&amp;lt; I'd done the (typically 9-point moving average) smoothing of those daily temps. Probably not what we'd want, although you might be able to argue it's a legitimate procedure to &quot;smooth the baseline&quot;. In any event, baselines for gif's below display means-before-smoothing, i.e., the raw daily temps are summed over all displayed years, and those generate animations that are a bit more &quot;jittery&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So first, here's the now-labelled jan1-dec31 animation (each frame displaying all years, left-to-right, for one day-of-the-year). The first &quot;4&quot; in the &quot;4x4 smoothing&quot; label refers to the smoothing across days as discussed earlier, and the second &quot;4&quot; refers to the smoothing across years...&#xA;&lt;a href=&quot;https://i.stack.imgur.com/3qEwN.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3qEwN.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;hr&gt;&lt;br&gt;Secondly, CR's median suggestion didn't really have much effect, one way or the other. Immediately below are the static gif's showing the yearly-deviations-from-the mean/median, 1869(left)-to-2017(right)...&#xA;&lt;a href=&quot;https://i.stack.imgur.com/b4kKQ.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/b4kKQ.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/gJKcP.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gJKcP.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;You probably think they're identical. But download both and quickly click between them. The median's &quot;translated upwards&quot; by maybe $1/4^oC$ (I think that's a mean/median skew), and the shape's ever-so-slightly different in a few spots. Go figure. Anyway, here are the corresponding one-year-per-frame (jan1-dec31 left-to-right) animations...&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Ybixf.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ybixf.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/wEvDG.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wEvDG.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;hr&gt;&lt;br&gt; In case you might want to &quot;play&quot; with these animations, I've uploaded a statically-linked linux executable of the program at&lt;br&gt;&#xA;&amp;nbsp; &amp;nbsp; &lt;a href=&quot;http://www.forkosh.com/ghcn.exe&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.forkosh.com/ghcn.exe&lt;/a&gt; &amp;nbsp; (ignore the windows-like .exe, it's linux elf)&lt;br&gt;&#xA;and the .dly file I've been using is at&lt;br&gt;&#xA;&amp;nbsp; &amp;nbsp; &lt;a href=&quot;http://www.forkosh.com/USW00094728.dly&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.forkosh.com/USW00094728.dly&lt;/a&gt; &amp;nbsp;&lt;br&gt;&#xA;although you can get that (and about a zillion other .dly files) from the ghcn link in the original question. (The statically-linked ghcn.exe should include all needed libraries/versions not natively installed by your particular linux distribution, but that doesn't always work. But it did work as compiled/linked on my box, and run on my ISP's box.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's run from the command line with up to 9 command-line arguments...&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;/* --- command-line args (all tests) --- */&#xA;int   testnum = ( argc&amp;gt;1? atoi(argv[1]) : 1 );&#xA;char  *file   = ( argc&amp;gt;2?      argv[2]  : &quot;USW00094728.dly&quot; ); /*CntrlPk*/&#xA;int   msglevel= ( argc&amp;gt;3? atoi(argv[3]) : 0 );&#xA;  /* --- command-line args for test#2 --- */&#xA;  char *types    =( argc&amp;gt;4?      argv[4]  :  &quot;TMAX&quot; ); /*&quot;TMIN&quot;,&quot;TMAX&quot;*/&#xA;  int  years     =( argc&amp;gt;5? atoi(argv[5]) : 1869149 ); /* yyyyNNN */&#xA;  int  meankind  =( argc&amp;gt;6? atoi(argv[6]) :       1 ); /*1=avg, 2=median*/&#xA;  int  ndlysmooth=( argc&amp;gt;7? atoi(argv[7]) :       2 ); /*smooth dly tmps*/&#xA;  int  nylysmooth=( argc&amp;gt;8? atoi(argv[8]) :       2 ); /*smooth yly tmps*/&#xA;  double bigf    =( argc&amp;gt;9? atof(argv[9]) :     4.0 ); /*max graph deg C*/&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;So my typical run would look like...&lt;br&gt;&#xA; &amp;nbsp; &amp;nbsp; &lt;strong&gt;./ghcn.exe 2 USW00094728.dly 999 TMAX 1869149 2 4 4 4&lt;/strong&gt; &lt;br&gt;&#xA;And your first three args, &lt;strong&gt;2 USW00094728.dly 999&lt;/strong&gt; should always be identical (except for that .dly file if you download some others). The first &lt;strong&gt;2&lt;/strong&gt; for &lt;em&gt;testnum&lt;/em&gt; is the only test generating relevant gif's. The others (actually only one other) mainly prints some data for unit-testing the data collection-and-selection functions. And the &lt;strong&gt;999&lt;/strong&gt; for &lt;em&gt;msglevel&lt;/em&gt; will print just a few lines which you can ignore.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The remaining six args can be varied. You replace my &lt;strong&gt;TMAX&lt;/strong&gt; by &lt;strong&gt;TMIN&lt;/strong&gt; to get corresponding gif's for you-know-what. (I have yet to think about JT's earlier suggestion for one gif incorporating several ghcn element &quot;types&quot;.) Trying any other ghcn element &quot;type&quot; (I haven't tested any yet) will use the same $0.1$ scale factor applied to temps (though that's easily made another arg).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The next arg's the date-plus-#years. My &lt;strong&gt;1869149&lt;/strong&gt; means start with year 1869 and use 149 years data in all, in this case meaning 1869-2017 inclusive (and that's pretty much the entire .dly file). The &lt;strong&gt;2&lt;/strong&gt; after the years is CR's mean/median, with &lt;strong&gt;1&lt;/strong&gt;=mean, &lt;strong&gt;2&lt;/strong&gt;=median. The three numbers after that, coincidentally (but not necessarily) the same &lt;strong&gt;4&amp;nbsp;4&amp;nbsp;4&lt;/strong&gt; in my example, are (first &lt;strong&gt;4&lt;/strong&gt;) the number-of-days forward-and-backwards for daily smoothing, and (second &lt;strong&gt;4&lt;/strong&gt;) #days for yearly smoothing. &lt;strong&gt;0&lt;/strong&gt; for either/both means no smoothing in that &quot;direction&quot;. Finally, the last &lt;strong&gt;4&lt;/strong&gt; is the $\pm$degreesC from the baseline displayed on the graphs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Output is three files: ghcn.gif, ghcn2.gif and (you guessed it) ghcn3.gif. The first is the year-by-year animation, the second is the day-by-day animation, and the last is the static gif displaying year-average deviation from the mean/median, first year to last.&lt;/p&gt;&#xA;" OwnerUserId="13783" LastEditorUserId="13783" LastEditDate="2018-09-10T09:31:46.543" LastActivityDate="2018-09-10T09:31:46.543" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15070" PostTypeId="2" ParentId="15062" CreationDate="2018-09-11T04:05:11.933" Score="2" Body="&lt;p&gt;You can find &lt;a href=&quot;https://www.google.com/search?q=air+flow+hurricane&amp;amp;client=ubuntu&amp;amp;hs=7gc&amp;amp;channel=fs&amp;amp;source=lnms&amp;amp;tbm=isch&quot; rel=&quot;nofollow noreferrer&quot;&gt;diagrams of air flow in hurricanes&lt;/a&gt;. If your balloon has neutral buoyancy it will go with the flow. Good luck in the complicated currents in the rainbands and eyewall.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2018-09-11T04:05:11.933" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15072" PostTypeId="2" ParentId="7982" CreationDate="2018-09-11T09:11:06.410" Score="-2" Body="&lt;p&gt;The ash(which contains minerals), is, by virtue of its containing minerals, fertile in the sense of 1.2 from the oxford online dictionary quoted in the question, &quot;encouraging a particular activity or feeling&quot;  Sure that line does say  'fertile ground' as it says &quot;encouraging a particular activity or feeling: conditions at the time provided fertile ground for revolutionary movements&quot;     But that usage of fertile could be applied to ash that contains minerals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not fertile in the sense of producing, but fertile in the sense of encouraging. Which is also a sense mentioned in the OED/Oxford English Dictionary quoted by Point &quot;causing or tending to promote fertility&quot;&lt;/p&gt;&#xA;" OwnerUserId="5960" LastActivityDate="2018-09-11T09:11:06.410" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15073" PostTypeId="1" AcceptedAnswerId="15076" CreationDate="2018-09-11T09:28:35.757" Score="4" ViewCount="1307" Body="&lt;p&gt;I read this line in my textbook:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;Lower Horizons of arid soil are occupied by calcareous deposits called kankar because of the increasing calcium content downwards.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My question is that why only in arid soil? Increase of calcium content will led to formation of kankars in other types of soil also, then why it happens only in arid soil? &lt;/p&gt;&#xA;" OwnerUserId="13610" LastActivityDate="2018-09-11T10:32:15.623" Title="Calcareous deposits in arid soil?" Tags="|soil|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15076" PostTypeId="2" ParentId="15073" CreationDate="2018-09-11T10:32:15.623" Score="8" Body="&lt;p&gt;Karkar is made of calcium carbonate.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;then why it happens only in arid soil?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Because this is what happens to calcium carbonate in wet environments:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QGxn8.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QGxn8.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It dissolves away, forming a cave. Calcium carbonate, or calcite, is soluble in mildly acidic solutions. Rainwater is mildly acidic because of CO&lt;sub&gt;2&lt;/sub&gt; from the atmosphere dissolving in it, so it never allows for the formation of calcium carbonate deposits in the soil to begin with.&lt;/p&gt;&#xA;&lt;p&gt;As for why it forms in arid soils, the Wikipedia page for &lt;a href=&quot;https://en.wikipedia.org/wiki/Caliche&quot; rel=&quot;noreferrer&quot;&gt;Caliche&lt;/a&gt; explains it well:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Caliche generally forms when minerals leach from the upper layer of the soil (the A horizon) and accumulate in the next layer (the B horizon), at depths around 3 to 10 feet under the surface. It generally consists of carbonates in semiarid regions—in arid regions, less-soluble minerals form caliche layers after all the carbonates have been leached from the soil. The deposited calcium carbonate accumulates—first forming grains, then small clumps, then a discernible layer, and finally, a thicker, solid bed. As the caliche layer forms, the layer gradually becomes deeper, and eventually moves into the parent material, which lies under the upper soil horizons.&lt;/p&gt;&#xA;&lt;p&gt;However, caliche also forms in other ways. It can form when water rises through capillary action. In an arid region, rainwater sinks into the ground very quickly. Later, as the surface dries out, the water below the surface rises, carrying up dissolved minerals from lower layers. This water movement forms a caliche that tends to grow thinner and branch out as it nears the surface. Plants can contribute to the formation of caliche, as well. Plant roots take up water through transpiration, and leave behind the dissolved calcium carbonate, which precipitates to form caliche. It can also form on outcrops of porous rocks or in rock fissures where water is trapped and evaporates. In general, caliche deposition is a slow process, but if enough moisture is present in an otherwise arid site, it can accumulate fast enough to block a drain pipe.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;(photo from &lt;a href=&quot;http://www.naturephoto-cz.com/karst-cave-photo-24442.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.naturephoto-cz.com/karst-cave-photo-24442.html&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-09-11T10:32:15.623" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15080" PostTypeId="1" CreationDate="2018-09-11T19:01:08.487" Score="3" ViewCount="55" Body="&lt;p&gt;I want to understand what makes for a very strong extratropical cyclone. So which kind on Earth is the strongest in terms of windspeed or pressure? Southern ocean storms, nor'easter, European wind storms etc. And what makes them so strong?&lt;/p&gt;&#xA;" OwnerUserId="13819" LastEditorUserId="595" LastEditDate="2018-09-12T15:31:28.683" LastActivityDate="2018-09-14T07:54:24.730" Title="What is the most powerful kind of extratropical cold core cyclone and why?" Tags="|meteorology|cyclone|" AnswerCount="0" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15082" PostTypeId="2" ParentId="13891" CreationDate="2018-09-12T01:09:55.590" Score="1" Body="&lt;p&gt;I don't think you can define a direct relationship between soil temperature and organic carbon - at least in a general sense.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As temperature increases so does soil microbial activity, which will tend to decrease soil carbon, not increase it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, plant growth will also increase &lt;em&gt;if there is sufficient water and nutrient availability&lt;/em&gt;. That will tend to increase soil organic matter. So soil organic matter is dominated by factors other than temperature. Some examples: Boreal forest in northern Canada contains areas of peat bog with abundant organic matter. Much of the native soil in the moderate rainfall (~350mm/yr) areas of southeastern Australia has very low organic matter.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2018-09-12T01:09:55.590" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15083" PostTypeId="1" CreationDate="2018-09-12T04:19:20.957" Score="5" ViewCount="551" Body="&lt;p&gt;The weather conditions of both peaty soil and laterite soil are the same, i.e. high rainfall &amp;amp; temperature. But the former turns out to become 'excessive organic' whereas the latter becomes 'excessive decayed' soil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the reason of this, that even after same climatic conditions they turn out to show opposite bacterial activity? &lt;/p&gt;&#xA;" OwnerUserId="13610" LastEditorUserId="2470" LastEditDate="2020-04-17T18:41:12.487" LastActivityDate="2020-04-17T18:41:12.487" Title="Peaty soil vs laterite soil" Tags="|soil|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15084" PostTypeId="2" ParentId="14489" CreationDate="2018-09-12T09:30:25.053" Score="5" Body="&lt;p&gt;Let me answer this question indirectly. When a pressure cooker partially filled with liquid water is heated up, there will be more water vapour molecules in the air inside pressure cooker but volume of pressure cooker still remains same. Only thing that changes inside the pressure cooker is pressure and temperature of air.&lt;/p&gt;&#xA;&lt;p&gt;Volume of gas is determined by ideal-gas law which states that &lt;em&gt;PV = nRT&lt;/em&gt; where &lt;em&gt;P&lt;/em&gt; is pressure, &lt;em&gt;V&lt;/em&gt; is volume, &lt;em&gt;n&lt;/em&gt; is amount of gas, &lt;em&gt;R&lt;/em&gt; is a constant and &lt;em&gt;T&lt;/em&gt; is temperature. If P and T remain same then adding more gas (increasing &lt;em&gt;n&lt;/em&gt;) would result in change in V (volume). However, the factors that affect pressure and temperature of air are so highly variable and large that minuscule volume increment expected from amount of CO&lt;sub&gt;2&lt;/sub&gt; does not matter. However, CO&lt;sub&gt;2&lt;/sub&gt; by absorbing infrared radiation increases temperature and that results in increase in volume which is a topic of active research.&lt;/p&gt;&#xA;" OwnerUserId="10780" LastEditorUserId="2470" LastEditDate="2021-11-01T17:25:07.980" LastActivityDate="2021-11-01T17:25:07.980" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15086" PostTypeId="1" CreationDate="2018-09-12T15:17:33.583" Score="7" ViewCount="271" Body="&lt;p&gt;This is at Bua Tong Waterfalls in  Chiang Mai, Thailand.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZBfjb.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZBfjb.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tried to find scientific information about this waterfall, but google turns up only travellers' vague guesses, suggesting calcium carbonate rich waters. The rock itself seems to have formed by layers of crystallised minerals, and is soft enough to be scratched with a strong stick. It is also quite grippy, allowing tourists to walk up unusually steep surfaces.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What causes such waterfalls and rocks to form, and what are its characteristics?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="13824" LastEditorDisplayName="user12525" LastEditDate="2019-08-27T11:15:34.273" LastActivityDate="2019-08-27T11:15:34.273" Title="What caused this waterfall to have rounded formations?" Tags="|geology|sedimentology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15088" PostTypeId="2" ParentId="15086" CreationDate="2018-09-12T19:55:02.463" Score="6" Body="&lt;p&gt;Looks like alkali earths ( Ca, Ba , etc.) carbonates deposited from a supersaturated hot spring. As the water emerges from the spring, carbon dioxide leaves the water and the water cools, it precipitates the carbonate ; you could call it limestone. There may be other minerals that will precipitate from a spring. From the foliage , it looks like a relatively recent development.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2018-09-12T19:55:02.463" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15089" PostTypeId="2" ParentId="14489" CreationDate="2018-09-12T20:23:06.373" Score="13" Body="&lt;p&gt;[&lt;strong&gt;Major edits below&lt;/strong&gt;]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short the answer is NO.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Before we get into volume changes, I have to say that volume is a tricky measure to apply to the atmosphere as a whole, because there is no clear limit between the atmosphere and outer space.&#xA;Also, the thickness of the atmosphere is quite insensitive to changes in atmospheric mass. For example, the atmosphere of Venus is much more massive than Earth's (&lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Venus#Troposphere&quot; rel=&quot;noreferrer&quot;&gt;93 times more massive&lt;/a&gt;). Leading to surface pressures 92 times those of Earth. However, the thickness of the atmosphere is quite similar, with the &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Venus#Upper_atmosphere_and_ionosphere&quot; rel=&quot;noreferrer&quot;&gt;mesosphere extending to 120 km&lt;/a&gt;, only 41% higher than on the Earth, despite having 9300% the mass.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This planetary comparison suggests that more CO$_2$ will lead to a more massive atmosphere and higher atmospheric pressures, but little change in its actual volume (if you somehow manage to define how to measure the volume of the atmosphere).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an analogy, imagine you have one meter of snow cover, and there is one meter of snowfall. You won't end up with two meters of snow cover. Thise is because the new snow will compact the snow below, leading to something like 1.7 meters of snow cover.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, more gases in the atmosphere will lead to a denser atmosphere, but have little impact on its thickness.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now we have to make a very important distinction: It is not the same to add CO$_2$ from a CO$_2$ source (like a volcanic eruption) than add it due to combustion of fossil fuels. This is because the latter do not add molecules to the atmosphere, just turn O$_2$ molecules into CO$_2$. Now, if you look into what this transformation means in terms of volume, you will get a surprise (at least it was a surprise to me):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given standard conditions (20°C and 1 atm). &lt;a href=&quot;https://www.engineeringtoolbox.com/gas-density-d_158.html&quot; rel=&quot;noreferrer&quot;&gt;One cubic meter of O$_2$ weights 1.331 kg&lt;/a&gt;. When you use that oxygen to burn fossil fuels all the molecules in it will go from a molecular weight of 32 (O$_2$) to 44.01 (CO$_2$), meaning you end up with 1.831 kg of CO$_2$. Now comes the interesting part: &lt;a href=&quot;https://www.engineeringtoolbox.com/gas-density-d_158.html&quot; rel=&quot;noreferrer&quot;&gt;under the same conditions, one cubic meter of CO$_2$ weights 1.842 kg&lt;/a&gt;, consequently, our initial cubic meter of O$_2$ turned into 0.994 m$^3$ of CO$_2$, equivalent to a volume reduction of 0.6%. Therefore, &lt;strong&gt;burning fossil fuels reduces the volume of the atmosphere&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was surprised at first by this result, but it nicely explain the classic experiment where a boiled egg get sucked into a bottle:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/zYc5z.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zYc5z.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;This is an screenshot of &lt;a href=&quot;https://www.youtube.com/watch?v=28TIyWdfxxc&quot; rel=&quot;noreferrer&quot;&gt;this video&lt;/a&gt; where you can see the trick in action (skip to minute 1:10)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, despite that burning stuff decrease the volume of the atmosphere. It is important to note that if you add greenhouse gases like CO$_2$ or methane, you are not only increasing the amount of those gases in the atmosphere, because the increase in temperature will lead to an increase in water vapor too. So the atmospheric mass increase will be larger than the mass of CO$_2$ or methane added. And that extra mass is related to additional molecules, so it will lead to extra volume (contrary to the combustion case where the amount of molecules is constant).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, as we burn fossil fuels the mass of the atmosphere increases (as well as the atmospheric pressure), but the volume decreases, and due to the fact that CO$_2$ is the product of combustion, that increase will be at the expense of reducing the amount of molecular oxygen (O$_2$).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although, this decrease is very small: the atmosphere have ~21% of Oxygen and 0.04% of CO$_2$, so an increase in CO$_2$ of a 30% (similar to going from 300 to 400 ppm), means a reduction of O$_2$ of 0.01%, a relatively small change (using &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Earth#Composition&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia numbers&lt;/a&gt; it would go from 20.946% Oxygen to 20.934%). Also, that's strictly true only if you make an instantaneous combustion. Because over time there could be negative feedback working against this imbalance. For instance, plants will increase the rate of photosynthesis (&lt;a href=&quot;https://en.wikipedia.org/wiki/CO2_fertilization_effect&quot; rel=&quot;noreferrer&quot;&gt;CO$_2$ fertilization effect&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, the mass increase (and volume decrease) associated to the CO$_2$ jumping from 300 ppm (pre-industrial levels) to 400 ppm is negligible, and probably dwarfed by day to day changes in particulate material or water vapor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a side note, the book &quot;&lt;a href=&quot;https://books.google.ca/books/about/Red_Mars.html?id=QqR301wsX-wC&amp;amp;source=kp_cover&amp;amp;redir_esc=y&quot; rel=&quot;noreferrer&quot;&gt;Red Mars&lt;/a&gt;&quot;, makes a fairly scientifically sound description of how to &quot;terraform&quot; Mars, and how adding CO$_2$, or water vapor increase the atmospheric pressure and surface temperature.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-09-14T19:06:49.177" LastActivityDate="2018-09-14T19:06:49.177" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="15091" PostTypeId="1" CreationDate="2018-09-13T05:30:38.533" Score="0" ViewCount="482" Body="&lt;p&gt;Can I clean fossil samples with acetone, or will this damage them?&lt;/p&gt;&#xA;" OwnerUserId="13829" LastEditorUserId="595" LastEditDate="2018-09-13T07:32:13.840" LastActivityDate="2018-09-13T12:22:18.013" Title="Cleaning fossil samples with acetone" Tags="|paleontology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15092" PostTypeId="2" ParentId="15091" CreationDate="2018-09-13T12:22:18.013" Score="1" Body="&lt;p&gt;It depends on what you want to use them for.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you might someday want to extract DNA from them, or do some other chemical analysis, then it's probably a bad idea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you only want to display them, and you like the way they look after acetone treatment, then it should be OK.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Test on some samples you don't care about first.&lt;/p&gt;&#xA;" OwnerUserId="12787" LastActivityDate="2018-09-13T12:22:18.013" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15093" PostTypeId="1" AcceptedAnswerId="15094" CreationDate="2018-09-13T14:03:25.330" Score="2" ViewCount="743" Body="&lt;p&gt;In todays world, 71% of the surface is covered in water. But was this always the case, far prehistoric times?&#xA;Id guess you can estimate pretty precisely where the prehistoric oceans were based on sediments, but i cant find a single answer to the question - even though you can see detailed maps of Laurassia, Gondwana and Pangaea.&lt;/p&gt;&#xA;" OwnerUserId="13837" OwnerDisplayName="Flying Thunder" LastActivityDate="2018-09-13T15:40:20.663" Title="Land to ocean ratio in jurassic era" Tags="|geography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15094" PostTypeId="2" ParentId="15093" CreationDate="2018-09-13T15:40:20.663" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://www.britannica.com/science/Jurassic-Period&quot; rel=&quot;nofollow noreferrer&quot;&gt;Britannica&lt;/a&gt; says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... because of the significant tectonic activity occurring around the world, it is not clear which of these local changes can be correlated&#xA;  to global sea level change. Because there is no evidence of major&#xA;  glaciations in the Jurassic, any global sea level change must have&#xA;  been due to thermal expansion of seawater or plate tectonic activity&#xA;  (such as major activity at seafloor ridges). Some geologists have&#xA;  proposed that average sea levels &lt;strong&gt;increased from Early to Late Jurassic time&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Notice, that we have no information about the change of the mass of water from Jurassic till now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even the articles &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S2095383615000267&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/S2095383615000267&lt;/a&gt; that shows, how the sea level changed, touch only relative changes in the sea level. As we don't know the statistics for depths and heights for these times, we can &lt;strong&gt;guess&lt;/strong&gt;, that the ocean/land area ratio was greater than now, but the guess is very wild. Any number of percents could be only a sheer speculation.&lt;/p&gt;&#xA;" OwnerUserId="13833" LastActivityDate="2018-09-13T15:40:20.663" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15095" PostTypeId="1" AcceptedAnswerId="15104" CreationDate="2018-09-13T20:51:33.847" Score="3" ViewCount="432" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8xyst.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8xyst.jpg&quot; alt=&quot;Photo 1.&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/BCUWh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BCUWh.jpg&quot; alt=&quot;Photo 2.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This palm-sized rock is from &lt;a href=&quot;https://www.google.co.uk/maps/@52.8091526,1.5674864,18z/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;the beach at Eccles-on-Sea&lt;/a&gt; (North Sea coastline).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can see four types of material:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;A brown, slightly translucent, 6cm tubular fossil(?) that I can mark with a steel blade;&lt;/li&gt;&#xA;&lt;li&gt;Coarse, light material--stained reddish-brown in places--that I can scratch away with a fingernail;&lt;/li&gt;&#xA;&lt;li&gt;Hard, dimpled, dark-brown material that I can't scratch (iron perhaps?); and&lt;/li&gt;&#xA;&lt;li&gt;Shiny black stone that I can't scratch.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I'm mostly interested in the fossil--if it is a fossil. Thank you. :-)&lt;/p&gt;&#xA;" OwnerUserId="13835" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T09:15:36.563" LastActivityDate="2019-08-29T09:15:36.563" Title="Fossil from North Norfolk coast, UK" Tags="|fossils|paleontology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15097" PostTypeId="2" ParentId="13728" CreationDate="2018-09-14T06:59:21.277" Score="3" Body="&lt;p&gt;Adsorption is adhesion of thin film of liquid or gas on solid substance and the host solid substance does not form chemical bond with deposited material. Uptake is entering of material into substance, end product of which is a solution. Uptake generally happens in liquid host substances but it is also possible for solid host substance to uptake the gas or liquid. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In context of aerosols, the term adsorption is used when solid aerosol particles like dust, soot, ice, etc. are interacting with gases. The term uptake is used when liquid aerosol particle are interacting with gases. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reference&#xA;&lt;a href=&quot;http://glossary.ametsoc.org/wiki/Adsorption&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://glossary.ametsoc.org/wiki/Adsorption&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="10780" LastActivityDate="2018-09-14T06:59:21.277" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15099" PostTypeId="2" ParentId="4374" CreationDate="2018-09-14T12:58:01.413" Score="3" Body="&lt;p&gt;It does look like a typical dendritic flow pattern of surface water flowing into a stream.  What is unusual for this pattern is that these channels seem to be entering the river at 90 degrees.  However, if the water is flowing out of the river through breaches in the bank or berm, then these branches would be carrying water and sediment out of the river and into a low lying area forming miniature deltas.  If you Google &quot;delta flow pattern&quot; you will see some pictures of this same pattern.&lt;/p&gt;&#xA;" OwnerUserId="13838" LastActivityDate="2018-09-14T12:58:01.413" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15100" PostTypeId="1" AcceptedAnswerId="15101" CreationDate="2018-09-14T15:36:00.070" Score="3" ViewCount="303" Body="&lt;p&gt;Question says it all really. It appears that every hurricane hitting the US East Coast directs itself north once on land.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.bbc.co.uk/news/world-us-canada-45517260&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hurricane Florence&lt;/a&gt; is predicted to hit North Carolina then turn toward Canada&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Meteorological_history_of_Hurricane_Katrina&quot; rel=&quot;nofollow noreferrer&quot;&gt;Katrina&lt;/a&gt; -&gt; Floridan and Louisiana -&gt; Great Lakes&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Meteorological_history_of_Hurricane_Dennis&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dennis&lt;/a&gt; -&gt; Florida -&gt; Great Lakes &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0kryV.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0kryV.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13840" LastActivityDate="2018-09-14T16:10:49.837" Title="Why do hurricanes hitting the US East Coast seem to go north once hitting land?" Tags="|meteorology|tropical-cyclone|storms|severe-weather|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15101" PostTypeId="2" ParentId="15100" CreationDate="2018-09-14T16:00:34.563" Score="5" Body="&lt;p&gt;&lt;a href=&quot;http://www.hurricanescience.org/science/science/hurricanemovement/&quot; rel=&quot;noreferrer&quot;&gt;It is mostly due to the Coriolis effect (aka Coriolis Force).&lt;/a&gt; (&lt;a href=&quot;https://www.quora.com/How-does-the-Coriolis-effect-disturb-hurricanes&quot; rel=&quot;noreferrer&quot;&gt;Another reference here&lt;/a&gt;) Because of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Coriolis_force&quot; rel=&quot;noreferrer&quot;&gt;Coriolis Effect&lt;/a&gt;, parcels of air (think of boxes of air) in the northern hemisphere are deflected to the right. This means that air around the subtropical ridge over the Atlantic ocean circulates clockwise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Think of a tropical cyclone as a parcel, or box of air. It tries to complete the clockwise rotation around the subtropical high.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, inevitably someone will say 'Aha! I know of a storm that actually moved south.' Yes, different things can cause tropical cyclones to move in strange directions, such as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Fujiwhara_effect&quot; rel=&quot;noreferrer&quot;&gt;Fujiwhara Effect&lt;/a&gt;, other meteorological features. But by and large, the Coriolis force is the dominant cause of the curvature of the path of tropical cyclones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is also worth pointing out that the hurricane also has parcels of air inside of it. &lt;a href=&quot;http://www.aoml.noaa.gov/hrd/hrd_sub/gradbal.html&quot; rel=&quot;noreferrer&quot;&gt;The Coriolis Force acts on that too, promoting rotation.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2018-09-14T16:00:34.563" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15104" PostTypeId="2" ParentId="15095" CreationDate="2018-09-15T06:21:43.223" Score="5" Body="&lt;p&gt;The round one is a belemnite... The grid-shaped fossil is a bryozoan. Bryozoans were (and are) marine colony building organisms often encrusting shells and other hardgrounds in the oceans. There are also solitary bryozoan colonies, which form screw-like shapes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.redbubble.com/de/people/seenickphotos/works/11168931-bryozoa-fossil-permian-era?p=Poster&quot; rel=&quot;noreferrer&quot;&gt;A nice picture of a bryozoan similar to yours can be seen here&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="13398" LastActivityDate="2018-09-15T06:21:43.223" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15105" PostTypeId="1" AcceptedAnswerId="15110" CreationDate="2018-09-15T06:24:33.400" Score="1" ViewCount="150" Body="&lt;p&gt;I captured this news channel picture on Sept 11 2018 from India.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EeASD.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EeASD.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can clear see It is live telecast from Mumbai, but it is still day time.&lt;/p&gt;&#xA;" OwnerUserId="13843" LastActivityDate="2018-09-18T07:14:07.867" Title="Why is it still day in Mumbai at 6:47 PM?" Tags="|earth-rotation|sun|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15106" PostTypeId="2" ParentId="15105" CreationDate="2018-09-15T06:31:52.210" Score="2" Body="&lt;p&gt;Sundown in Mumbai is 18:47 today... I guess it is the problem of a huge country having only one time zone (same for China)... Mumbai is at the western coast and the Indian Standard Time is based on Kolkata (which is far more east)... Sundown in Kolkata in around 17:40...&lt;/p&gt;&#xA;" OwnerUserId="13398" LastActivityDate="2018-09-15T06:31:52.210" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15107" PostTypeId="1" CreationDate="2018-09-15T13:43:02.553" Score="2" ViewCount="255" Body="&lt;p&gt;If we have a place with wind at a given speed, and a tornado at the same speed, are they equally dangerous, or the tornado is more powerful?&lt;/p&gt;&#xA;" OwnerUserId="13846" LastActivityDate="2020-05-07T04:03:00.210" Title="At the same speed, is a tornado as dangerous as straight wind?" Tags="|wind|tropical-cyclone|storms|tornado|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15109" PostTypeId="2" ParentId="8947" CreationDate="2018-09-15T14:18:03.223" Score="1" Body="&lt;p&gt;Unless you're needing specific methods for application purposes, the justification you're providing is clear and wouldn't require a citation. Maybe this is a homework question? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Some rambling thoughts:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Larger watersheds typically have a larger time of concentration. Where things becomes tricky for larger watersheds is that assumptions around rainfall distribution may break down. For example, a really really large watershed may only receive a 100-year storm in the lower or upper reaches of that watershed. So, there's that to consider. If you're looking at a specific watershed, check out some reflectivity data to gauge spatial variability of rainfall [&lt;a href=&quot;https://gis.ncdc.noaa.gov/maps/ncei/radar&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;]. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the US, you might look for USGS-based studies for your area of interest as a starting point. For a large river with a time of concentration approaching days, many of these are gauged and therefore, you may be able to research that area specifically. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For small, urban time of concentration calculations, some standard references for engineering applications are the National Engineering Handbook, Part 630 for hydrology [&lt;a href=&quot;https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/national/water/manage/hydrology/?cid=stelprdb1043063&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;] , or the NRCS TR 55 text [&lt;a href=&quot;https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1044171.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;]. These types of applications usually calculate time-of-concentration using velocity-based methods, which are tied-to rainfall intensity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;1: &lt;a href=&quot;https://gis.ncdc.noaa.gov/maps/ncei/radar&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://gis.ncdc.noaa.gov/maps/ncei/radar&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2: &lt;a href=&quot;https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/national/water/manage/hydrology/?cid=stelprdb1043063&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nrcs.usda.gov/wps/portal/nrcs/detailfull/national/water/manage/hydrology/?cid=stelprdb1043063&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3: &lt;a href=&quot;https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1044171.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb1044171.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5475" LastActivityDate="2018-09-15T14:18:03.223" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15110" PostTypeId="2" ParentId="15105" CreationDate="2018-09-15T14:29:54.877" Score="4" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/b6Qvi.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/b6Qvi.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This image from &lt;a href=&quot;https://www.timeanddate.com/sun/india/mumbai&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.timeanddate.com/sun/india/mumbai&lt;/a&gt; shows that daylight ended at 6:44, so 6:47 was three minutes into civil twilight and pretty much close to daylight.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Notice the orange light in the back - I'm assuming that this is a &lt;a href=&quot;https://en.wikipedia.org/wiki/Sodium-vapor_lamp&quot; rel=&quot;nofollow noreferrer&quot;&gt;street lamp&lt;/a&gt;, which are only turned on at twilight.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most likely the image appears relatively bright because of camera settings, not because it is full daylight outside.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-09-15T14:29:54.877" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15111" PostTypeId="2" ParentId="14642" CreationDate="2018-09-15T15:14:56.913" Score="1" Body="&lt;p&gt;I'll preface by saying I have no hands-on experience with either model; however, HSPF has always seemed cumbersome whereas SWAT seems more user friendly. Again, just my read of the software without any practical experience. But, until that person comes along to answer you're question, here's my two cents:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The best way to answer this questions is to sit down with the model documentation side-by-side and compare [&lt;a href=&quot;https://swat.tamu.edu/media/99192/swat2009-theory.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;https://nepis.epa.gov/Exe/ZyNET.exe/91018NWD.txt?ZyActionD=ZyDocument&amp;amp;Client=EPA&amp;amp;Index=1995%20Thru%201999%7C1976%20Thru%201980%7C2006%20Thru%202010%7C1991%20Thru%201994%7C2000%20Thru%202005%7C1986%20Thru%201990%7C1981%20Thru%201985%7CPrior%20to%201976&amp;amp;Docs=&amp;amp;Query=600980015&amp;amp;Time=&amp;amp;EndTime=&amp;amp;SearchMethod=2&amp;amp;TocRestrict=n&amp;amp;Toc=&amp;amp;TocEntry=&amp;amp;QField=&amp;amp;QFieldYear=&amp;amp;QFieldMonth=&amp;amp;QFieldDay=&amp;amp;UseQField=&amp;amp;IntQFieldOp=0&amp;amp;ExtQFieldOp=0&amp;amp;XmlQuery=&amp;amp;File=D%3A%5CZYFILES%5CINDEX%20DATA%5C76THRU80%5CTXT%5C00000025%5C91018NWD.txt&amp;amp;User=ANONYMOUS&amp;amp;Password=anonymous&amp;amp;SortMethod=-%7Ch&amp;amp;MaximumDocuments=15&amp;amp;FuzzyDegree=0&amp;amp;ImageQuality=r85g16/r85g16/x150y150g16/i500&amp;amp;Display=hpfr&amp;amp;DefSeekPage=x&amp;amp;SearchBack=ZyActionL&amp;amp;Back=ZyActionS&amp;amp;BackDesc=Results%20page&amp;amp;MaximumPages=1&amp;amp;ZyEntry=1&amp;amp;SeekPage=x&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;]. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both HSPF and SWAT are intended for estimating pollutant loading to rivers, so if you're not interested in pollution modeling, there are better/simpler tools out there. If you're interested in typical non-point source pollutants like phosphorous and nitrogen, SWAT might be the better tool since the user manual emphasizes nutrient cycles and would be easier to follow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the SWAT Manual, &quot;SWAT was developed to predict the impact of land management practices on water, sediment and agricultural chemical yields in large complex watersheds.&quot; Since the model was specifically designed with the intention of modeling agricultural systems, the model contains crop growth and nutrient cycling. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From a quick review of the HSPF manual, it seems that there are modules that would allow you to track a specific pollutant of interest, if you can supply the model with an appropriate relationship. This is discussed in the PQUAL module. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quoting from the HSPF Manual here: The PQUAL module section simulates water quality constituents or pollutants in the outflows from a pervious land segment using simple relationships with water and/or sediment yield. &lt;em&gt;Any constituent can be simulated by this module section&lt;/em&gt;. The user supplies the name, units and parameter values appropriate to each of the constituents that he wishes to simulate. However, more detailed methods of simulating sediment, heat, dissolved oxygen, dissolved carbon dioxide, nitrogen, phosphorus, soluble tracers, and pesticide removal from a pervious land segment are available, in other module sections.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Last - these are just two examples for modeling. If you're interested in general sediment transport, there are a whole host of programs out there. You'd be better served by defining your problem explicitly as hydrology and hydrology software are broad and far reaching.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Links:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1: &lt;a href=&quot;https://swat.tamu.edu/media/99192/swat2009-theory.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://swat.tamu.edu/media/99192/swat2009-theory.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2: &lt;a href=&quot;https://nepis.epa.gov/Exe/ZyNET.exe/91018NWD.txt?ZyActionD=ZyDocument&amp;amp;Client=EPA&amp;amp;Index=1995%20Thru%201999%7C1976%20Thru%201980%7C2006%20Thru%202010%7C1991%20Thru%201994%7C2000%20Thru%202005%7C1986%20Thru%201990%7C1981%20Thru%201985%7CPrior%20to%201976&amp;amp;Docs=&amp;amp;Query=600980015&amp;amp;Time=&amp;amp;EndTime=&amp;amp;SearchMethod=2&amp;amp;TocRestrict=n&amp;amp;Toc=&amp;amp;TocEntry=&amp;amp;QField=&amp;amp;QFieldYear=&amp;amp;QFieldMonth=&amp;amp;QFieldDay=&amp;amp;UseQField=&amp;amp;IntQFieldOp=0&amp;amp;ExtQFieldOp=0&amp;amp;XmlQuery=&amp;amp;File=D%3A%5CZYFILES%5CINDEX%20DATA%5C76THRU80%5CTXT%5C00000025%5C91018NWD.txt&amp;amp;User=ANONYMOUS&amp;amp;Password=anonymous&amp;amp;SortMethod=-%7Ch&amp;amp;MaximumDocuments=15&amp;amp;FuzzyDegree=0&amp;amp;ImageQuality=r85g16/r85g16/x150y150g16/i500&amp;amp;Display=hpfr&amp;amp;DefSeekPage=x&amp;amp;SearchBack=ZyActionL&amp;amp;Back=ZyActionS&amp;amp;BackDesc=Results%20page&amp;amp;MaximumPages=1&amp;amp;ZyEntry=1&amp;amp;SeekPage=x&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://nepis.epa.gov/Exe/ZyNET.exe/91018NWD.txt?ZyActionD=ZyDocument&amp;amp;Client=EPA&amp;amp;Index=1995%20Thru%201999%7C1976%20Thru%201980%7C2006%20Thru%202010%7C1991%20Thru%201994%7C2000%20Thru%202005%7C1986%20Thru%201990%7C1981%20Thru%201985%7CPrior%20to%201976&amp;amp;Docs=&amp;amp;Query=600980015&amp;amp;Time=&amp;amp;EndTime=&amp;amp;SearchMethod=2&amp;amp;TocRestrict=n&amp;amp;Toc=&amp;amp;TocEntry=&amp;amp;QField=&amp;amp;QFieldYear=&amp;amp;QFieldMonth=&amp;amp;QFieldDay=&amp;amp;UseQField=&amp;amp;IntQFieldOp=0&amp;amp;ExtQFieldOp=0&amp;amp;XmlQuery=&amp;amp;File=D%3A%5CZYFILES%5CINDEX%20DATA%5C76THRU80%5CTXT%5C00000025%5C91018NWD.txt&amp;amp;User=ANONYMOUS&amp;amp;Password=anonymous&amp;amp;SortMethod=-%7Ch&amp;amp;MaximumDocuments=15&amp;amp;FuzzyDegree=0&amp;amp;ImageQuality=r85g16/r85g16/x150y150g16/i500&amp;amp;Display=hpfr&amp;amp;DefSeekPage=x&amp;amp;SearchBack=ZyActionL&amp;amp;Back=ZyActionS&amp;amp;BackDesc=Results%20page&amp;amp;MaximumPages=1&amp;amp;ZyEntry=1&amp;amp;SeekPage=x&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5475" LastActivityDate="2018-09-15T15:14:56.913" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15112" PostTypeId="2" ParentId="15086" CreationDate="2018-09-15T16:27:39.610" Score="3" Body="&lt;p&gt;It's either, as blacksmith37 suggests a &lt;a href=&quot;https://en.wikipedia.org/wiki/Calcite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Calcite&lt;/a&gt; deposit or possibly, given how tectonically active Thailand is, it's &lt;a href=&quot;https://en.wikipedia.org/wiki/Silicon_dioxide&quot; rel=&quot;nofollow noreferrer&quot;&gt;Silica&lt;/a&gt; from geothermal springs. Geothermal silica often forms large &lt;a href=&quot;https://en.wikipedia.org/wiki/Sintering#Natural_sintering_in_geology&quot; rel=&quot;nofollow noreferrer&quot;&gt;sinter&lt;/a&gt; deposits such as the famous &lt;a href=&quot;https://en.wikipedia.org/wiki/Pink_and_White_Terraces&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pink and White Terraces&lt;/a&gt;, now either destroyed or partially buried at the bottom of Lake Rotomahana, but also much smaller formations in many geothermally active areas throughout the world.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-09-15T16:27:39.610" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15117" PostTypeId="1" AcceptedAnswerId="15131" CreationDate="2018-09-16T18:30:13.283" Score="5" ViewCount="196" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/dnrQw.jpg&quot; alt=&quot;feature&quot;&gt;&#xA;Hello,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We were walking in Bundoran in Donegal County, Ireland today and we encountered the geological feature shown in the picture (from above from cliffs and from very close up at beach level). We have three questions about it?&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;How would you call it? It looks to me like the tall rocks on the sides are sea stacks but isn’t the eroded bit in the middle more like a sea stump? Or are they something different altogether?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;What type of rock is it (in the close-up pics) Our guess is that it is shale, but it could also be limestone. Which one do you think it is?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Please notice the ubiquitous fossils in the close-ups. Are we correct to think they are crinoids?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I have just realised a good view from top of this feature is available on Google, so I am sharing it here as well:&#xA;&lt;a href=&quot;https://www.google.com/maps/@54.4852881,-8.2823865,3a,75y,49.15h,69.55t/data=!3m8!1e1!3m6!1sAF1QipNS26PrjyPwTfKnxdxVE29LHtp7A8TctpDVSjl1!2e10!3e11!6shttps:%2F%2Flh5.googleusercontent.com%2Fp%2FAF1QipNS26PrjyPwTfKnxdxVE29LHtp7A8TctpDVSjl1%3Dw203-h100-k-no-pi-0-ya103.88327-ro-0-fo100!7i8192!8i4096&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.google.com/maps/@54.4852881,-8.2823865,3a,75y,49.15h,69.55t/data=!3m8!1e1!3m6!1sAF1QipNS26PrjyPwTfKnxdxVE29LHtp7A8TctpDVSjl1!2e10!3e11!6shttps:%2F%2Flh5.googleusercontent.com%2Fp%2FAF1QipNS26PrjyPwTfKnxdxVE29LHtp7A8TctpDVSjl1%3Dw203-h100-k-no-pi-0-ya103.88327-ro-0-fo100!7i8192!8i4096&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Than you in advance for answering all our questions.&lt;/p&gt;&#xA;" OwnerUserId="13852" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T07:44:33.243" LastActivityDate="2019-08-28T07:44:33.243" Title="Geological feature - what is it?" Tags="|sedimentology|fossils|paleontology|erosion|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15119" PostTypeId="2" ParentId="14653" CreationDate="2018-09-16T21:36:45.390" Score="1" Body="&lt;p&gt;Without seeing the details of the topography, you are correct in your assumption that water will infiltrate down past the tree root-zone to the water table. The shallow groundwater will likely form a local flow system, discharging to the stream, although some may form a deeper system that forms a regional aquifer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the groundwater is discharging to the stream you &lt;em&gt;may&lt;/em&gt; be looking at relatively shallow depth to water when you are in the valley that close. It depends a lot on the amount of rainfall that recharges the groundwater and the topography, as well as the soil and rock type. It is impossible to say from the information you have given on what the depth to bedrock will be.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That being said, these shallow flow systems can have poor quality water and can even be affected by contaminants from the stream (e.g. when it floods).&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2018-09-16T21:36:45.390" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15120" PostTypeId="1" CreationDate="2018-09-17T07:26:04.590" Score="2" ViewCount="60" Body="&lt;p&gt;I have a confined aquifer of sand. I will temporarily drain the aquifer, remove the top one meter of the aquifer and then replace that with a layer of gravel. After that I will restore the layer (and the aquitard above it). After that, it is a confined layer again. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the storage of the aquifer different with the small layer of gravel? &lt;/p&gt;&#xA;" OwnerUserId="13855" LastEditorUserId="10681" LastEditDate="2018-10-10T00:38:56.990" LastActivityDate="2019-01-08T02:03:05.687" Title="Does the configuration of a confined layer change the storage?" Tags="|hydrology|groundwater|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15121" PostTypeId="2" ParentId="14974" CreationDate="2018-09-17T13:10:22.547" Score="5" Body="&lt;p&gt;As noted by Barry Carter, you could take a look at &lt;a href=&quot;https://www.emsc-csem.org/Earthquake/Map/zoom.php?key=75&amp;amp;typ=NAM#5&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.emsc-csem.org/Earthquake/Map/zoom.php?key=75&amp;amp;typ=NAM#5&lt;/a&gt; to see the earthquakes around San Francisco, with a table below giving the time and date of the earthquake(s). The USGS can create a similar data-set (&lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/map/#%7B%22feed%22%3A%221537188489965%22%2C%22sort%22%3A%22newest%22%2C%22mapposition%22%3A%5B%5B35.705%2C-123.904%5D%2C%5B39.702%2C-117.993%5D%5D%2C%22viewModes%22%3A%5B%22list%22%2C%22map%22%5D%2C%22autoUpdate%22%3Afalse%2C%22search%22%3A%7B%22id%22%3A%221537188489965%22%2C%22name%22%3A%22Search%20Results%22%2C%22isSearch%22%3Atrue%2C%22params%22%3A%7B%22starttime%22%3A%222014-08-18%2000%3A00%3A00%22%2C%22endtime%22%3A%222018-09-17%2023%3A59%3A59%22%2C%22maxlatitude%22%3A39.702%2C%22minlatitude%22%3A35.705%2C%22maxlongitude%22%3A-117.993%2C%22minlongitude%22%3A-123.904%2C%22minmagnitude%22%3A2.5%2C%22orderby%22%3A%22time%22%7D%7D%7D&quot; rel=&quot;nofollow noreferrer&quot;&gt;try there&lt;/a&gt;). I used that to extract the earthquakes of magnitude 2.5+ in the SF area over the last 4 years:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EpwTP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EpwTP.png&quot; alt=&quot;Earthquakes in the SF area of mag. 2.5+ per hour, for 4 years&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or the same data with a Kernel Density Estimator in a polar plot (the circle corresponds to 24 hours):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/okdgb.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/okdgb.png&quot; alt=&quot;Earthquakes in the SF Area with a polar KDE plot&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Based on these plots, I think that there is no specific trend suggesting that earthquakes are triggered at specific times.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earthquakes tend to have their 'core' at depths of a few km's usually, which means that they are not very aware of day-night cycles. Apart from perhaps very minor influence of gravitational differences due to sun/moon locations (which vary over the course of a month), the earthquakes truly follow their own 'random schedule' with respect to our life-cycle!&lt;/p&gt;&#xA;" OwnerUserId="12155" LastEditorUserId="12155" LastEditDate="2018-09-18T10:00:10.500" LastActivityDate="2018-09-18T10:00:10.500" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15123" PostTypeId="1" AcceptedAnswerId="15124" CreationDate="2018-09-17T17:09:26.193" Score="2" ViewCount="55" Body="&lt;p&gt;I think I have the hang of black-body radiation: a black body receives radiation passively and then emits some portion of it (the earth emits stored solar heat, e.g.).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a parallel term for something like the sun that generates its own radiation? &lt;/p&gt;&#xA;" OwnerUserId="2440" LastActivityDate="2018-09-18T04:48:57.560" Title="Term for the thing that shines radiation onto a black body" Tags="|solar-terrestrial-physics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15124" PostTypeId="2" ParentId="15123" CreationDate="2018-09-17T17:32:03.420" Score="4" Body="&lt;p&gt;The Sun is also regarded as a black body. Any body that radiates energy following &lt;a href=&quot;https://en.wikipedia.org/wiki/Planck%27s_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Planck's law of black-body radiation&lt;/a&gt;, and absorbes energy at all wavelengths can be considered as a black body. This is an idealization, but if Earth is approximated to a black body, the Sun can be considered one as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The case of the sun is not very different to that of Earth: The stuff that makes up both is mostly opaque (plasma for the sun rock for the Earth), but at some point both bodies become transparent (in the Sun when it is cold enough such that electrons recombine with atomic nucleus and form gases, in the Earth at the base of the atmosphere), the base of the transparent layer and the transparent layers themselves emit electromagnetic radiation according to their temperature following &lt;a href=&quot;https://en.wikipedia.org/wiki/Planck%27s_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Planck's law of black-body radiation&lt;/a&gt;, and absorb pretty much any incoming radiation regardless of its wavelength.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The concept of black body (or gray body) only refers at the fact that a body absorb all (or a constant fraction for a gray body) the energy it receives regardless of the wavelength (color), therefore it looks black. Similarly, it must emit in all wavelength too, with the intensity at each wavelength (color) following &lt;a href=&quot;https://en.wikipedia.org/wiki/Planck%27s_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Planck's law of black-body radiation&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore a mirror is not a black body, neither is a fluorescent lamp, nor a tomato. Because a tomato reflects red light more than green. However, if the thermal balance of a tomato is mainly controlled by the exchange of infrared radiation, you can treat it as a black body, because it acts as one in the infrared spectrum (i.e. if your eyes were sensitive to infrared radiation only, a tomato would look black or gray). In the same way, despite the fact that Earth isn't black, it can be approximated to a black body and with such approximation you can get very accurate results of its energy balance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Going back to your point. Black bodies can have internal energy sources (like the Sun), and in the absence of the Sun, the hot interior of Earth would also act as an energy source and the Earth would emit more energy than it receives, in the same way the Sun does.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So anything can shine radiation onto a black body, that is precicely because it is a black body and absorb all kinds of electromagnetic radiation. I hope this clarifies your doubt. &lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-09-18T04:48:57.560" LastActivityDate="2018-09-18T04:48:57.560" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15126" PostTypeId="1" CreationDate="2018-09-17T22:09:02.557" Score="1" ViewCount="30" Body="&lt;p&gt;What changes in the weather prior to thunderstorms (day before, for example)? It seems humidity goes up and temperature but is there anything else? &lt;/p&gt;&#xA;" OwnerUserId="13860" LastActivityDate="2018-09-17T22:09:02.557" Title="what changes in the weather prior to thuderstorms?" Tags="|meteorology|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15127" PostTypeId="2" ParentId="15105" CreationDate="2018-09-18T07:14:07.867" Score="1" Body="&lt;p&gt;You may be surprised to hear this, but in my home country Germany, sunset was around 10pm in the summer. Where I now live, in Colorado, sunset was today at 7:03pm. It all depends on how far east or west you are in your current time zone, and how far north/south you are relative to where the sun currently circles the Earth.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2018-09-18T07:14:07.867" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15128" PostTypeId="1" AcceptedAnswerId="15286" CreationDate="2018-09-18T09:02:30.103" Score="1" ViewCount="357" Body="&lt;p&gt;Wikipedia's definition of astrochronology is:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Astrochronology is the dating of sedimentary units by calibration&#xA;  with astronomically tuned timescales, such as Milankovic cycles,&lt;a href=&quot;https://en.wikipedia.org/wiki/Astrochronology&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;[2]&#xA;  or even sunspot cycles. When used in concert with radiometric dating,&#xA;  it allows the resolution of timescales to a high degree of accuracy.&#xA;  If orbital precession cycles are identified, the dating error can be&#xA;  as low as 21,000 years.&quot;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Astrochronology&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Question:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Is this method really used and does it have a good reputation among field geologists?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2018-10-04T11:12:53.363" LastActivityDate="2018-10-09T18:01:08.500" Title="Is astrochronology a proper method?" Tags="|geology|geochronology|field-measurements|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15129" PostTypeId="1" CreationDate="2018-09-18T10:53:51.153" Score="3" ViewCount="95" Body="&lt;p&gt;For personal reasons I decided to examine the shape and formation of the Rhine. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately though, the Rhine has long been diverted from its original course by human intervention, so I tried to find how it originally looked like prior to this, but without much success.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone have a source s/he could share with me, or perhaps even describe how and in which way it was diverted from its course?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you very much! &lt;/p&gt;&#xA;" OwnerUserId="13862" LastEditorUserId="10681" LastEditDate="2018-09-19T13:08:03.173" LastActivityDate="2018-09-19T13:08:03.173" Title="How did the Rhine originally look like? (before human intervention)" Tags="|hydrology|rivers|human-influence|landscape|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15131" PostTypeId="2" ParentId="15117" CreationDate="2018-09-18T17:27:37.857" Score="2" Body="&lt;p&gt;1) I would call the formation a sea stack.  Effectively you have a band of rock which is either more resistant to the forces of erosion and weathering from the sea, or is located on top of a more resistant strata.  The more eroded portion is just that, a more eroded portion, and by its absence tend to identify the rest as a sea stack.&#xA;2) The matrix, the rock with the fossils, looks like a limey shale, or a limestone with a lot of shale or clay in it.  It appears to have a component of lime or CaCO3 in it.  This could be confirmed by placing a small amount of dilute HCL or Muriatic Acid on the rock and seeing if it fizzes.&lt;br&gt;&#xA;3) There are definitely crinoid stem sections in this rock, as mentioned by JulPal.  If you look carefully at this rock you will likely find a number of other fossils.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get a tighter description you will have to give more information about the rocks&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Treatment of this rock with a dilute acid bath might show a number of fossils.  See the article here &lt;a href=&quot;https://museum.wales/articles/2011-06-07/Fossils-in-stone-acid-preparation-of-fossils/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://museum.wales/articles/2011-06-07/Fossils-in-stone-acid-preparation-of-fossils/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2018-09-18T17:27:37.857" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15133" PostTypeId="2" ParentId="15129" CreationDate="2018-09-19T05:57:13.407" Score="7" Body="&lt;p&gt;It would help if you'd ask a more clear question -- it's a dynamic river system so it is literally changing its shape every second! The story over long time-scales can be found on Wikipedia: &lt;a href=&quot;https://en.wikipedia.org/wiki/Rhine#Geologic_history&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Rhine#Geologic_history&lt;/a&gt; . You can find some more detailed information with some overview maps (esp. Fig 3) here &lt;a href=&quot;https://www.sedimentologie.uni-freiburg.de/staff/Preusser2008NJG.pdf&quot; rel=&quot;noreferrer&quot;&gt;https://www.sedimentologie.uni-freiburg.de/staff/Preusser2008NJG.pdf&lt;/a&gt; .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In broad terms, the Rhine in its current state is due to two processes. First of all, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Northern_North_Sea_basin&quot; rel=&quot;noreferrer&quot;&gt;North Sea Basin&lt;/a&gt;, i.e., North-West Europe is sinking constantly, providing a great place for rivers to deposit sediments. This is why the Rhine ends up in the Netherlands, because the Rhine can deposit large amounts of sediment without silting up and blocking its own course. Second of all, the formation of the Alps caused a huge potential for sediment transport (realizing that all that rivers really do is transport water and sediment from high points to low points), and the Alpine orogeny furthermore caused the creation of the Rhine Graben. The Rhine thus found the perfect source (high Alpine mountains), channel (Rhine Graben) and deposition space (North Sea Basin).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The story over smaller time-scales also plays over smaller distances. The Rhine changed its course during glaciations for example, because the advancing ice caps pushed sand out in front of them (&lt;a href=&quot;https://en.wikipedia.org/wiki/Moraine&quot; rel=&quot;noreferrer&quot;&gt;moraines&lt;/a&gt;), in the Netherlands this literally pushed the rivers into a more southern course. The story about these details goes on and on and on! If you have any specific questions, you may want to contact the &lt;a href=&quot;https://www.tno.nl/en/focus-areas/ecn-part-of-tno/roadmaps/geological-survey-of-the-netherlands/&quot; rel=&quot;noreferrer&quot;&gt;Geological Survey of the Netherlands&lt;/a&gt; or &lt;a href=&quot;https://www.bgr.bund.de/EN/Home/homepage_node_en.html&quot; rel=&quot;noreferrer&quot;&gt;Geological Survey of Germany&lt;/a&gt;, they have people who dedicate their lives to studying the past and the present Rhine!&lt;/p&gt;&#xA;" OwnerUserId="12155" LastActivityDate="2018-09-19T05:57:13.407" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15136" PostTypeId="2" ParentId="15107" CreationDate="2018-09-19T11:00:22.440" Score="0" Body="&lt;p&gt;I think that in this situation the primary difference would be the fact that the tornado is more capable of moving air (and possibly objects) upwards. Whereas regular wind would mainly cause lateral displacement of entrained objects. Consequently it is also dependent on the setting: the lateral wind might cause high waves and flooding in a coastal setting.&#xA;A second consideration originates from the driving forces: regular winds are mainly driven by air pressure gradients which on itself are not 'dangerous'. Tornado's, on the other hand, often are induced by weather systems that include heavy electrical charges (potential thunderstroms) and hail. &#xA;This might not answer your question explicitly but I hope this gives some insight in the considerations &lt;/p&gt;&#xA;" OwnerUserId="13870" LastActivityDate="2018-09-19T11:00:22.440" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15137" PostTypeId="1" AcceptedAnswerId="15152" CreationDate="2018-09-19T14:42:03.663" Score="5" ViewCount="1089" Body="&lt;p&gt;I am currently reading a textbook and I am slightly confused at a paragraph that deals with some general facts about earth's outer shape. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It mentions that the density of the continental crust is less than the density of the oceanic crust. Then it concludes (somehow?) that the continental lithospheres weigh less than the oceanic lithospheres. Using this then, it says that the continental lithospheres are &quot;floating more up&quot; on the asthenosphere  than the oceanic lithospheres. And then it continues with other facts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I feel like there's something missing here. I understand that the denser material will sink in more. But how does this affect earth's outer shape? I mean sure, it means that the continental crust will appear more higher than the oceanic, but I fail to see this. All pictures I have seen don't show this clearly. Could someone maybe explain this in more detail with an appropriate image or animation?&lt;/p&gt;&#xA;" OwnerDisplayName="user13873" LastEditorUserId="11430" LastEditDate="2018-09-20T06:14:35.977" LastActivityDate="2020-06-22T11:53:37.550" Title="How do the different densities of the oceanic and continental crust affect earth's outer shape?" Tags="|geology|geophysics|crust|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15139" PostTypeId="2" ParentId="6515" CreationDate="2018-09-19T18:17:58.367" Score="16" Body="&lt;p&gt;I get 40.4%&lt;/p&gt;&#xA;&lt;p&gt;With a workflow using a tiny bit of Python.&lt;/p&gt;&#xA;&lt;ol start=&quot;0&quot;&gt;&#xA;&lt;li&gt;&lt;p&gt;After &lt;a href=&quot;https://earthscience.stackexchange.com/questions/6515/in-the-northern-hemisphere-only-what-percentage-of-the-surface-is-land/15139#comment49016_15139&quot;&gt;Polygorial‘s comment&lt;/a&gt; I am adding (&lt;strong&gt;Updated on Feb 17, 2021&lt;/strong&gt;) point zero to state more explicitly that this method requires a map like the one I used (Gall-Peters projection) with equal area projection, as regions of same area on the Earth’s surface will have the same area on the map, and therefore same number of pixels.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Invert and import B/W &lt;a href=&quot;https://mycarta.files.wordpress.com/2018/09/peters_projection_black_north.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;image&lt;/a&gt; of equal area projection for the Northern hemisphere (land = white pixels). Source of original image (full globe): &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Peters_projection,_black.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikimedia Commons&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Store as Numpy array.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Calculate total number of pixels in image array (black + white).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Calculate total number of white pixels (1s) by summing the entire array (black pixels (0s) will amount to zero).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Calculate percentage of white pixels.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2ivd9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2ivd9.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE September 20, 2018&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;As suggested by @JeopardyTempest in a comment, as a validation test I run the script for the full image with both hemispheres, and got the expected 30%&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KtjF5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KtjF5.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="144" LastEditorUserId="144" LastEditDate="2022-06-02T04:06:50.053" LastActivityDate="2022-06-02T04:06:50.053" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="15140" PostTypeId="2" ParentId="15107" CreationDate="2018-09-19T18:58:51.963" Score="1" Body="&lt;p&gt;I'd have to say a tornado would be more dangerous than a straight wind of equal speed. Tornados have a very low-pressure center and violent updrafts as can be seen in &lt;a href=&quot;https://www.youtube.com/watch?v=UmpqbKORv-Q&quot; rel=&quot;nofollow noreferrer&quot;&gt;this YouTube video &lt;/a&gt;. As the roofs are blown off you'll notice they get blown upward as well as sideways.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2018-09-19T18:58:51.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15141" PostTypeId="1" CreationDate="2018-09-19T20:58:39.023" Score="5" ViewCount="56" Body="&lt;p&gt;There are several permanent seismograph stations in Eastern Canada that have been recording arrival times for over 25 years. Using refracted Pn arrival times from natural earthquakes I would like to determine Moho depths and Pn velocities of the region, then develop the information into either a 2D or 3D model. However, I am having a tough time figuring out a way to go about it including what specific seismic method I should be using to generate the best model that fits the data. For those geophysicists that understand this procedure well, would you please advise me as specifically as possible as to how to go about the problem.&lt;/p&gt;&#xA;" OwnerUserId="13875" LastActivityDate="2018-09-19T20:58:39.023" Title="How do I generate a Moho depth model from seismic refraction data?" Tags="|geology|geophysics|earthquakes|seismic|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15143" PostTypeId="2" ParentId="15137" CreationDate="2018-09-20T00:13:27.523" Score="0" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;It mentions that the density of the continental crust is less than the density of the oceanic crust. Then it concludes (somehow?) that the continental lithospheres weigh less than the oceanic lithospheres.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Density = mass / volume. For a given volume of substance (like lithosphere), the less dense one (continental) will weigh less than the other (oceanic).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I understand that the denser material will sink in more. But how does this affect earth's outer shape? I mean sure, it means that the continental crust will appear more higher than the continental, but I fail to see this. All pictures I have seen don't show this clearly.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Islands and continents sit higher than the bottoms of oceans. &lt;/p&gt;&#xA;" OwnerUserId="11430" LastActivityDate="2018-09-20T00:13:27.523" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15144" PostTypeId="2" ParentId="9951" CreationDate="2018-09-20T00:51:19.430" Score="1" Body="&lt;p&gt;Here is a Python Script showing how to download the required variables automatically. &#xA;&lt;a href=&quot;http://conorsweeneyucd.blogspot.com/2015/01/download-era-interim-data.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://conorsweeneyucd.blogspot.com/2015/01/download-era-interim-data.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13876" LastActivityDate="2018-09-20T00:51:19.430" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15146" PostTypeId="2" ParentId="10426" CreationDate="2018-09-20T08:12:10.107" Score="2" Body="&lt;p&gt;If you are not interested in the vertical flow occurring in your aquifer (which I assume is the case) then one can indeed add the recharge to the existing head!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In groundwater issues, we often assume the recharge to be constant over time and equal over distances when considering such problems. This is mainly due to simplification as we are often interested in horizontal flow rather than vertical flow. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That being said, in general I would consider recharge (as this seems to happen outside the system we are interested in) as a constant rather than a boundary condition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, when going into details, considering boundary conditions there are several ways to go:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Dirichlet boundary conditions:&lt;/strong&gt; Where we assume a constant head at a certain location. As we go from A to B, we could assume constant heads at these location(s), depending on your setup.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Neumann boundary conditions:&lt;/strong&gt; Where we assume a constant input/output discharge at a certain location. This could also be your recharge but also dependent on your setup.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Cauchy boundary conditions:&lt;/strong&gt; complex combination of the two where the input is related to a head. An example of this could be a river with head h_x feeding an adjacent confined aquifer with head h_x2&#xA;&#xA;&lt;p&gt;I hope this gives some insight in the application of appropriate boundary conditions. As you can see: it all depends on the characteristics of the system, the known values and your own considerations.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For further reading one might consider Fitts' Groundwater Science (fully available at ScienceDirect)&lt;/p&gt;&#xA;" OwnerUserId="13870" LastEditorUserId="13870" LastEditDate="2018-09-21T07:05:45.310" LastActivityDate="2018-09-21T07:05:45.310" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15148" PostTypeId="2" ParentId="14985" CreationDate="2018-09-20T22:11:31.400" Score="0" Body="&lt;p&gt;Volume of all oceans = 1.33E9 km^3. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Molar volume of water = 1.802E-14 km^3/mol&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Moles of water in the oceans = (1.33E9 km^3)*(1mol/1.802E-14 km^3) = 7.38E22 mol.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Enthalpy of vaporization of water = 40.65 kJ/mol&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Energy required to turn all of the oceans from liquid to gas = (40650 J/mol)*(7.38E22) = 3E27 joules.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How much energy is that? It's a lot. According to www.wolframalpha.com it is equal to as much energy as the sun produces in eight seconds. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;And that is only the amount of energy required to convert the liquid water into gas. It doesn't take into account the amount of energy required to heat the liquid up to 100C or the gas to escape velocity temperatures.&lt;/p&gt;&#xA;" OwnerUserId="11430" LastEditorUserId="11430" LastEditDate="2018-09-20T22:18:33.083" LastActivityDate="2018-09-20T22:18:33.083" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15149" PostTypeId="1" AcceptedAnswerId="15166" CreationDate="2018-09-20T23:01:33.327" Score="6" ViewCount="164" Body="&lt;p&gt;After reading &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2956/what-is-the-origin-of-the-oceans-salt&quot;&gt;this question about the origin of NaCl on Earth&lt;/a&gt;, I'm wondering: How did the amount of NaCl develop historically? Is it a more or less linear growth until today? Was it such a linear growth and then reached a level that it maintains until now? Or was that more complex over the billions of years of Earth's existence?&lt;/p&gt;&#xA;" OwnerUserId="13255" LastActivityDate="2018-09-23T11:06:27.447" Title="Historically, how did the total amount of salt / NaCl on Earth develop?" Tags="|geology|geochemistry|earth-history|geochronology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15150" PostTypeId="2" ParentId="12642" CreationDate="2018-09-21T12:39:15.910" Score="3" Body="&lt;p&gt;I add some information here to present the control strategies which have been done by China government.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A series of paper have reported that coal combustion is the main cause of the air pollution in China. This issue usually gets worse in the winter months due to the fact that coal is used for domestic heating.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the winter of 2017, China government decided to transform the fuel types for each of the residents even in rural areas within north Chian as fast as possible.  Here is a figure I captured near my campus, the giant pipes convey the natural gas to each of the residents for heating and other uses.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Paj73.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Paj73.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although the heating fee might increase, the consumption of coal, especially for those bulk coal (known as cheap with high amount of emissions) was cut significantly. &#xA;The effects of energy structure adjustment has been observed clearly. As shown in this figure presenting the monthly variations of PM2.5 in 2015, 2016 and 2017, the improvement of air quality is an obvious one. Especially in December when the strict control strategies were implemented, the concentration decreased sharply compared to 2015/2016.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/apFL2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/apFL2.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By sharing the example of Beijing, I make a point that the improvement of air quality is possible by applying the current technology. What's more, the movement from traditional fuels to clean fuels seems to be a more efficient approach compared to the end-of-pipe control with advanced technology.&lt;/p&gt;&#xA;" OwnerUserId="5214" LastEditorUserId="5214" LastEditDate="2018-09-29T04:30:10.163" LastActivityDate="2018-09-29T04:30:10.163" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15151" PostTypeId="1" CreationDate="2018-09-21T13:04:15.750" Score="1" ViewCount="77" Body="&lt;p&gt;I need to calculate water vapor budget for a selected region. Can anyone suggest a specific link or code for the above mentioned tools please. I have seen a link for NCL but i am not familiar with that tool. &#xA;Regards&lt;/p&gt;&#xA;" OwnerUserId="8158" LastActivityDate="2018-09-21T13:04:15.750" Title="How to calculate water vapor budget for a selected region in GRADS or MAT Lab" Tags="|meteorology|climatology|reanalysis|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15152" PostTypeId="2" ParentId="15137" CreationDate="2018-09-21T13:50:41.140" Score="2" Body="&lt;p&gt;The two confusions have everything to do with &lt;a href=&quot;https://en.wikipedia.org/wiki/Isostasy&quot; rel=&quot;nofollow noreferrer&quot;&gt;Isostasy&lt;/a&gt; as mentioned by Gimelist. I advise you to read the Wikipedia page because it will explain everything to you! But maybe this helps:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The continental crust is made up of relatively light-weight material compared to oceanic crust. That's really all that the authors of your book should have said.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The fundamental idea of isostasy is that from a certain depth onwards to the center of the earth, the &lt;em&gt;pressure&lt;/em&gt; is identical no matter where you are. This 'compensation point' is usually taken at about 100 km depth. This is an assumption about the physical state of the Earth -- it is thus an assumed reality!&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;This means that you can take &lt;em&gt;any&lt;/em&gt; single column from 100 km depth (say, a cylinder, or a square meter) and extend it all the way to the surface, and &lt;em&gt;all&lt;/em&gt; the columns that you could choose must weigh exactly the same (such that they cause the same pressure at 100 km depth). Mathematically, this is an integral over the densities(!) that you encounter as you move towards the Earth's surface: &lt;span class=&quot;math-container&quot;&gt;$\text{Pressure}=\text{mass}/\text{area}=\int_{100 \text{km depth}}^{\text{surface}(x)}\rho(x,z)\Delta z=\text{constant}$&lt;/span&gt;. It is the density that varies with &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt;, i.e. your location on the earth, that makes the exact location of the &lt;span class=&quot;math-container&quot;&gt;$\text{surface}$&lt;/span&gt; variable with &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; also!&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;So you're moving up in your column and summing all the densities you encounter every meter. Density is always positive, so your sum is always growing. You also know that the solution has a fixed, constant, solution. We could thus just keep integrating from 100 km depth towards the surface, and when our integral reaches the constant, we &lt;em&gt;know&lt;/em&gt; that we are at the earth's surface! That's a useful bit of information, because...&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;If the material in your column is relatively dense, the distance from 100 km depth until the &lt;span class=&quot;math-container&quot;&gt;$\text{surface}$&lt;/span&gt; must then also be relatively small, because you're reaching the integrated constant faster! And vice versa, if the material in your column is relatively light you know that the surface extends out relatively far. It then follows that the oceanic crust has its surface at a lower level than the continental crust, because it is about 20% denser.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Effects of buoyancy only make the matters worse, as continental crust tends to be much thicker than the oceanic crust, and correspondingly it 'floats' higher on the fluid-y astenosphere below it. This is much like an iceberg floating on the sea: a larger iceberg both sticks into the sea more and sticks out of the sea more. The continental crust does the same: it has a deeper base and higher surface than the continental crust, because it 'floats' on the more dense 'fluid' underneath.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;There are thus roughly two effects (although of very similar physical principles) that make the continental crust rise above the ocean crust: it is less dense and it is thicker! Therefore, continental crust rises &lt;em&gt;above&lt;/em&gt; continental crust to produce the same pressure at depth, and its base lies &lt;em&gt;below&lt;/em&gt; the oceanic crust because it is thicker (and floating like an iceberg).&lt;/p&gt;&#xA;&lt;p&gt;So the missing piece of information in your book was the perspective of a constant pressure. I hope that helps :-)&lt;/p&gt;&#xA;" OwnerUserId="12155" LastEditorUserId="12155" LastEditDate="2020-06-22T11:53:37.550" LastActivityDate="2020-06-22T11:53:37.550" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15153" PostTypeId="1" CreationDate="2018-09-21T14:19:58.823" Score="5" ViewCount="73" Body="&lt;p&gt;In this &lt;a href=&quot;https://link.springer.com/book/10.1007/978-3-540-74703-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;publication about data assimilation and observations&lt;/a&gt; (paywall alert) in the chapter General Concepts in Meteorology and Dynamics (by Andrew Charlton-Perez, William Lahoz, Richard Swinbank, Pages 325-349), while being a decade old, it is stated that the water vapour mixing ratio tendency in the stratosphere is positive according to sounding from Boulder, Colorado and negative according to UARS HALOE instrument and under research. I tried to google more resent research, but didn't get to a clear conclusion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would assume that the variability would emerge from the temperature changes in different layers of the atmosphere; warming levels would be able to hold more water vapour and vice versa (Clausius-Clapeyron equation for water vapour).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is the current understanding of the water vapour mixing ratio changes in time in different heights of the atmosphere?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6465" LastEditorUserId="6465" LastEditDate="2018-09-25T10:12:47.263" LastActivityDate="2018-09-25T10:12:47.263" Title="How is the vertical distribution of water vapor changing?" Tags="|climate-change|climate|water|climate-models|atmospheric-chemistry|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15156" PostTypeId="1" CreationDate="2018-09-21T18:24:38.620" Score="5" ViewCount="947" Body="&lt;p&gt;Clouds obviously have a strong effect on surface temperatures. By blocking sunlight they can decrease the temperature by several degrees. At night they have a blanket effect that traps warm air and can increase nighttime temperatures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm asking about long term averages that would affect climate, rather than transient levels that affect day-to-day weather. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From what I read, the way clouds will be affected by a change in global temperatures is still very much up in the air, if you'll pardon my pun. What I'm wanting to know is whether clouds are more likely to form during daylight hours, when water vapor is rising from the surface, or at night when the temperatures are lower. This might also be different between low altitude and high altitude clouds. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The articles I read are also not clear on whether clouds, currently, have a net warming or cooling effect. Is there any consensus on which is true? Intuitively, to me, it seems that the cooling effect of daytime cloud cover is many times higher than the warming affect of nighttime cloud cover. Am I wrong about this? &lt;/p&gt;&#xA;" OwnerUserId="13882" LastActivityDate="2018-09-21T18:24:38.620" Title="Are clouds more common at night?" Tags="|meteorology|climate|clouds|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15158" PostTypeId="1" AcceptedAnswerId="15159" CreationDate="2018-09-21T23:57:24.830" Score="2" ViewCount="1364" Body="&lt;p&gt;If the Earth was in a fixed equinox state, what would the equilibrium temperature be at each pole? Assume daily cycle and convection and so on operate as usual, just that it's permanent sunset at both poles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bonus questions: Would the equilibrium temperatures be significantly different if Earth was fixed at solstice?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Note: I misunderstood &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4636/what-would-the-equilibrium-temperature-be-at-the-poles-in-a-world-without-season&quot;&gt;this question&lt;/a&gt; and wrote an elaborate answer that wasn't the answer to that question. So, to do not throw my answer to the trash, I'm asking here the question I did answer, which I find rather interesting anyway).&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-09-22T00:03:08.603" LastActivityDate="2018-09-22T18:15:21.850" Title="What would happen to the Earth if there were no seasons?" Tags="|climate|seasons|ice-age|axial-obliquity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15159" PostTypeId="2" ParentId="15158" CreationDate="2018-09-21T23:57:24.830" Score="2" Body="&lt;p&gt;In a short timescale, let's say one or two years after a permanent equinox state, the temperature would be basically the current mean annual temperature. This is because if we take the premise of keeping heat transport by convection (on the sea and the atmosphere) as it it today, the total energy inputs and outputs would be the same. Therefore, the same mean annual temperature would occur but without seasonal variability.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To simplify things, let's use a simple model of temperature v/s latitude (that will also be useful in the discussion later):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tCqse.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tCqse.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image originally from &lt;a href=&quot;http://petroleumsystem.blogspot.com/2012/06/know-what-we-dont-know-about-surface.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Petroleum System Blog&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using that formula, the temperature at the poles (reduced to sea level) would be -16.8 °C (from the figure actual data points it can be seen that in real life the south pole is much colder than the north pole).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, the previous assumptions contradicts the requirement of &quot;equilibrium&quot;, because the above scenario is &lt;strong&gt;far from steady state&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So now I will go on to try to describe what would happen to Earth's climate in your hypothetical scenario:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing that we learned by studying how the &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;nofollow noreferrer&quot;&gt;Milankovitch cycles&lt;/a&gt; trigger and reverse &lt;a href=&quot;https://en.wikipedia.org/wiki/Quaternary_glaciation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pleistocene ice ages&lt;/a&gt;, is that to initiate an ice age cold winters are not necessary, what is needed are cold or mild summers.&#xA;Currently, the inclination of Earth axis (a.k.a. obliquity) varies between &lt;a href=&quot;https://en.wikipedia.org/wiki/Axial_tilt#Long_term&quot; rel=&quot;nofollow noreferrer&quot;&gt;22° and 24.5° , with a mean period of 41,040 years&lt;/a&gt;. When the inclination is 22°, mild summers occur and, therefore, the perfect condition to initiate an ice age (specially when combined with other ad-hoc orbital conditions). The permanent equinox situation you propose, is equivalent to an obliquity of 0°, that would lead to the coldest possible summer (this is, no summer at all). Therefore, such condition would set the Earth on track for an intense and never-ending ice age.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let me explain how this could work: Using the formula above, the temperatures would be permanently below zero between the poles and latitudes 58.3°. Therefore, snow would start to accumulate in those areas, building an ice sheet and once the ice sheet gets thick enough it would start flowing outwards.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6TW7h.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6TW7h.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Figure from &lt;a href=&quot;https://courses.lumenlearning.com/physicalgeology/chapter/16-2-how-glaciers-work/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lumen Learning&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ice sheet then becomes self-sustaining due to two positive feedbacks:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Due to its high albedo, it would reflect most of the solar radiation back to the space, cooling down the Earth.&lt;/li&gt;&#xA;&lt;li&gt;As the ice sheet advance, its thickness adds to the elevation of the terrain, therefore the surface is higher and colder, allowing snowfall beyond the 58.3° of latitude. The thicker it grows the more it can advance towards the equator.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Therefore, the polar ice sheets and their floating extensions (&lt;a href=&quot;https://en.wikipedia.org/wiki/Ice_shelf&quot; rel=&quot;nofollow noreferrer&quot;&gt;ice shelves&lt;/a&gt;), would slowly take over the Earth, and bring it to a state like the  &lt;a href=&quot;https://en.wikipedia.org/wiki/Snowball_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Snowball Earth&lt;/a&gt; hypothesis that proposes that Earth surface's became entirely or nearly entirely frozen at least once, sometime earlier than 650 Mya (million years ago).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In your scenario, the equator would constantly receive maximum solar irradiation, therefore, perhaps it could be spared by the ice sheets, but you would need to run a model to figure that out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But if we assume that the ice sheets would engulf the whole planet, it is easy to calculate the Earth's effective radiative temperature, that is equivalent to the mean temperature. To avoid going into the math (that is quite simple anyway), we can use the Indiana University's &lt;a href=&quot;http://www.astro.indiana.edu/ala/PlanetTemp/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Planet Temperature Calculator&lt;/a&gt;, that shows that if we crank Earth's albedo from the current 29% to a 80% (a &lt;a href=&quot;https://en.wikipedia.org/wiki/Albedo&quot; rel=&quot;nofollow noreferrer&quot;&gt;reasonable figure for snow&lt;/a&gt;), the mean temperature would drop from 15°C to -63°C. So it would be pretty cold. The actual temperature in the poles would depend on how much energy transport is there from the equator to the poles. A model would be needed to figure that out too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Eventually, it will happen what is usually thought to have allowed Earth to escape from ice ages: As the land is covered in ice, it can't take up CO&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt; from the atmosphere (normally happening due to the weathering of silicate rocks), but the volcanoes keep putting CO&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt; into the atmosphere. Therefore, at some point the amount of atmospheric CO&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt; is so large that the greenhouse effect can rise the temperature enough to melt the ice sheets and go back to what we call &quot;normal&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is already too long so I'll refrain to address that bonus question. However, I'll say that the orbital configuration to have permanent summer in either hemisphere would be quite difficult to attain. You would need the &lt;a href=&quot;https://en.wikipedia.org/wiki/Precession&quot; rel=&quot;nofollow noreferrer&quot;&gt;Precession&lt;/a&gt; period of the Earth to be (and remain) exactly one year long.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="2470" LastEditDate="2018-09-22T18:15:21.850" LastActivityDate="2018-09-22T18:15:21.850" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15160" PostTypeId="2" ParentId="12976" CreationDate="2018-09-22T07:59:22.390" Score="2" Body="&lt;p&gt;I do not think that there is a general relation between the temperature of an airflow and its velocity in meteorology. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are several physical processes that need to be considered when thinking about the surface winds in occluding cyclones or fronts. A possible mechanism that I could think of explaining the stronger winds in the cold air compared to the warm air is the difference in vertical stability. The colder air is often characterized by steeper lapse rates (a stronger decrease in temperature with height). This leads to more exchange of momentum between the near-surface air layer and the so-called free troposphere air aloft. This exchange accelerates the surface winds compared to a situation where there is less exchange (as is the case for the warm air in an occluding front).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a (wintertime) anti-cyclone, the cold air establishes itself mainly close to the surface due to radiative cooling. This leads to a very stable vertical profile, meaning that there is not much exchange of momentum between the near-surface layer and the air aloft. In such a situation, one can say that the surface layer is decoupled from the free troposphere. When a front moves in, it will simply move over the cold layer at the surface without disturbing it too much initially. The cold air indeed moves only slowly in this case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this explains at least a part of your question. &lt;/p&gt;&#xA;" OwnerUserId="13524" LastActivityDate="2018-09-22T07:59:22.390" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15161" PostTypeId="2" ParentId="12438" CreationDate="2018-09-22T13:32:34.417" Score="-2" Body="&lt;p&gt;There are two factors determining when the next glacial cycle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first concerns the natural cycle that has been at play since the beginning of our present day Ice Age (about 2.6 million years ago).  In this case the next glacial period ushers in as temperatures in the worlds oceans rise that in turn increases hurricane activity/force.  As hurricane activity eventually extends into winter months they bring blizzard conditions the likes of which are the building blocks of a glacial period. The increase in ocean temperatures is primarily the result of the North American and Eurasian tectonic plate adjusting from the previous glacial period, namely at the ice free peripheries that had bowled upward as a result of the massive glacial weight that covered continents.  These outer peripheries today lay mostly in the Oceans and so a resettling means “heat generated friction” as they grind along adjacent plates where the plate boundaries are convergent, and in the case where the boundaries are divergent, heat is generated as magma displaces into the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second factor determining when the next glacial period is due, is as a result of man-made global warming.  This will certainly change the “natural” game plan.  In the past (without man-made global warming), interglacials lasted about 10,000–20,000 years, and so we can extrapolate from this that the next glacial period can begin any time in the near future and before 8,500 years.   &lt;/p&gt;&#xA;" OwnerUserId="13887" LastEditorUserId="725" LastEditDate="2018-09-23T00:58:48.607" LastActivityDate="2018-09-23T00:58:48.607" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15162" PostTypeId="1" CreationDate="2018-09-22T15:42:06.840" Score="11" ViewCount="506" Body="&lt;p&gt;I have searched for an answer to this question for years, to verify if it was true.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A man that lived on a river in the rugged part of the northern Washington Cascades told me an interesting story. He actually lived on the upper reaches of the Cascade&#xA;River, a tributary, which eventually flows into the Skagit River. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The river is a high energy, steep gradient river full of rocks. Fast moving and cascading. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The man told me during a big flood flow, at night, he could hear the rocks and boulders bouncing around and bumping into each other. The most amazing thing is he&#xA;said in the pitch black of night, he saw muted, periodic, random quick light flashes under water - creating an unusual effect. He and I speculated the flashes were produced by rocks colliding with each other.  The rocks in the area were mostly granitic, perhaps with some gneiss. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I did not see it. Is this possible? I know you can get sparks from some rocks and minerals - but granite boulders - underwater!!? Any comments?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Larry&lt;/p&gt;&#xA;" OwnerUserId="13889" LastEditorUserId="10681" LastEditDate="2018-09-28T09:28:09.863" LastActivityDate="2022-11-26T05:08:26.513" Title="Rocks sparking under water" Tags="|geology|hydrology|rivers|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15163" PostTypeId="2" ParentId="10390" CreationDate="2018-09-22T17:16:24.143" Score="1" Body="&lt;p&gt;After initialization the model calculates forward in time ncluding all physical processes represented by your setup of WRF. This probably means that the warm air will rise and thereby trigger the supercell thunderstorm. Cape can be calculated for a parcel starting at any height. If the bubble (warm anomaly) is present at the surface, and you are interested in the so-called surface-based Cape, then I would set the temperature to the environmental temperature + the warm anomaly. Why not try out both and see what the difference is? This would give you an idea of the vertical forcing magnitude of the warm anomaly. &lt;/p&gt;&#xA;" OwnerUserId="13524" LastActivityDate="2018-09-22T17:16:24.143" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15164" PostTypeId="2" ParentId="15162" CreationDate="2018-09-23T01:06:59.413" Score="14" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is this possible? &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Definitely.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I know you can get sparks from some rocks and minerals - but granite boulders [?]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yep. Quartz is one of those minerals that &quot;sparks&quot;. It is &lt;a href=&quot;https://en.wikipedia.org/wiki/Piezoelectricity#Naturally_occurring_crystals&quot; rel=&quot;noreferrer&quot;&gt;piezoelectric&lt;/a&gt;, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Triboluminescence&quot; rel=&quot;noreferrer&quot;&gt;triboluminescent&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a wonderful video of this phenomenon: &lt;a href=&quot;https://commons.wikimedia.org/w/index.php?title=File%3ATribo.ogv&quot; rel=&quot;noreferrer&quot;&gt;https://commons.wikimedia.org/w/index.php?title=File%3ATribo.ogv&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Granite is a rock which has plenty of quartz in it. By &lt;a href=&quot;https://en.wikipedia.org/wiki/Granite#/media/File:Qapf_diagram_plutonic_05.svg&quot; rel=&quot;noreferrer&quot;&gt;definition&lt;/a&gt;, granite has more than 20% quartz.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;underwater!!? &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Why not? Those are properties of the quartz itself, not the surroundings. The light does not come from electric arcing of the air, it comes from electronic processes occurring within the crystal. The fact that there's water around it probably does not matter.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-09-23T01:06:59.413" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15166" PostTypeId="2" ParentId="15149" CreationDate="2018-09-23T11:06:27.447" Score="3" Body="&lt;p&gt;Here is a graph describing modern estimates of ocean salinity throughout the Phanerozoic (past ~550 million years). &lt;a href=&quot;https://i.stack.imgur.com/cMNIo.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cMNIo.gif&quot; alt=&quot;Salinity from Hay et al., 2006&quot;&gt;&lt;/a&gt;&#xA;The original PDF of this study can be found here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://core.ac.uk/download/pdf/11894545.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hay, W.W., Migdisov, A., Balukhovsky, A.N., Wold, C.N., Flögel, S. and Söding, E., 2006. Evaporites and the salinity of the ocean during the Phanerozoic: Implications for climate, ocean circulation and life. Palaeogeography, Palaeoclimatology, Palaeoecology, 240(1-2), pp.3-46.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As this graph shows, it is not linear at all and actually decreasing since the end of the Precambrian. This is a result of many factors including changing volume of ocean water, and the global chloride cycle. The details are all described in that paper. &lt;/p&gt;&#xA;" OwnerUserId="4783" LastActivityDate="2018-09-23T11:06:27.447" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15170" PostTypeId="1" AcceptedAnswerId="15179" CreationDate="2018-09-23T23:30:35.990" Score="2" ViewCount="261" Body="&lt;p&gt;In The Leading Edge tutorial article &lt;em&gt;Phase and the Hilbert transform&lt;/em&gt; (Purves 2014), there is the following line:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;So we apply a Hilbert transform by multiplying all negative frequencies by i and all positive frequencies by -i, leaving any DC component untouched.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I have two questions following this: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;1)&lt;/strong&gt; What is the DC component?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;2)&lt;/strong&gt; What is the significance of not affecting any DC component?&lt;/p&gt;&#xA;" OwnerUserId="8447" LastEditorUserId="6465" LastEditDate="2018-09-24T13:25:51.277" LastActivityDate="2018-09-25T20:03:09.160" Title="DC component in Hilbert transform concept for seismic data" Tags="|seismic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15173" PostTypeId="2" ParentId="14907" CreationDate="2018-09-24T21:32:04.463" Score="2" Body="&lt;p&gt;Yes, it is quite possible to have a number of earthquakes over an extended period of time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The phenomenon is actually quite common. Some famous sequences are: New Madrid in 1811-1812, Eastern California Shear Zone (1992-1999), Italy (2009-2016), New Zealand (2010-2011) etc. These are all areas where rates of seismicity are relatively low so a number of events in quick succession (as you saw in Lombok) is not due to pure chance. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The idea of one earthquake triggering another on a neighboring or nearby faults is not new.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastActivityDate="2018-09-24T21:32:04.463" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15175" PostTypeId="1" CreationDate="2018-09-25T16:28:49.877" Score="1" ViewCount="1454" Body="&lt;p&gt;The ozone layer if compressed to a minimum on the earth's surface can absorb infrared radiation. How is it possible that the same molecule can absorb radiation of two different wavelength with changing altitude? &lt;/p&gt;&#xA;" OwnerUserId="13905" LastEditorUserId="595" LastEditDate="2018-09-25T17:44:24.907" LastActivityDate="2018-09-27T21:32:05.973" Title="Ozone layer and radiation absorption" Tags="|atmosphere|ozone|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15177" PostTypeId="1" CreationDate="2018-09-25T19:47:37.657" Score="3" ViewCount="219" Body="&lt;p&gt;I read in Wikipedia that, &quot;Natural Nitrogen, Dinitrogen forms about 78% of Earth's atmosphere. Dinitrogen is the most abundant uncombined element in the atmosphere.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do man-made machines destroy the natural Nitrogen, the extremely strong triple bond in elemental nitrogen (N≡N), turning natural Nitrogen into other compounds, molecules?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does man-made fractional distillation, Nitrogen gas generators, and membranes take natural Nitrogen out of the atmosphere or ionosphere, causing global warming?&lt;/p&gt;&#xA;" OwnerUserId="13908" LastEditorUserId="595" LastEditDate="2018-10-26T14:17:19.900" LastActivityDate="2020-01-05T19:25:17.127" Title="Do man-made machines take natural Nitrogen out of the atmosphere and in turn cause global warming?" Tags="|atmosphere|climate-change|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15179" PostTypeId="2" ParentId="15170" CreationDate="2018-09-25T20:03:09.160" Score="1" Body="&lt;p&gt;The 'DC Component' is a standard term used to describe the mean energy of a signal ( &lt;a href=&quot;https://en.wikipedia.org/wiki/DC_bias&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/DC_bias&lt;/a&gt; ), which in the frequency domain corresponds to the component of 0 frequency. The DC component does not depend on the time -- while the other frequencies 'wiggle' around it. In seismic signals I think we don't generally have a DC components: the signal moves around a point of 0 pressure/displacement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The authors then make their statement in a bit of an awkward way in my opinion. What they mean, is that the Hilbert transform applied to any 'DC component' is 0: thrown away!&lt;/p&gt;&#xA;" OwnerUserId="12155" LastActivityDate="2018-09-25T20:03:09.160" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15180" PostTypeId="1" CreationDate="2018-09-25T20:52:19.027" Score="1" ViewCount="22" Body="&lt;p&gt;&lt;a href=&quot;http://sci.esa.int/rosetta/55118-deuterium-to-hydrogen-ratio-in-the-solar-system/&quot; rel=&quot;nofollow noreferrer&quot;&gt;It is known&lt;/a&gt; that the D/H-ratio of Earth's water inventory is very similar to that of asteroids. This is usually interpreted in a way that Earth's water must have come from similar, asteroid-like protoplanetary bodies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However I find it hard to conceive Earth as a initially dry rock, being bombarded with a bunch of Ceres-like objects and then all the water just sticks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems more plausible to me that asteroids would build the young Earth via classical collisional cascades, retain some water all the while, and degas this water later into the young atmosphere to form Oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This scenario only remains plausible if the degassing process (I'm thinking of volcanism, but maybe there are more?) leaves the D/H ratio as it was in the original asteroids.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;So my question&lt;/strong&gt;: Is that so? Does degassing from a source material usually leave the D/H ratio untouched?&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2018-09-25T20:52:19.027" Title="Does outgassing change the isotopic D/H ratio?" Tags="|volcanology|water|planetary-formation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15181" PostTypeId="2" ParentId="4636" CreationDate="2018-09-25T21:40:01.650" Score="4" Body="&lt;p&gt;If we consider that by &quot;Assume daily cycle and convection and so on operate as usual&quot; you meant that all heat transport from/to the pole remain as it is today. Then, we can do a back of the envelope calculation. This calculation will at least give you an order-of-magnitude answer, and we can then consider everything that would affect the result.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Currently both poles radiate more energy than they receive trough direct solar irradiation. This is because they are colder than the rest of the planet. Therefore, there is a neat heat transport from the equatorial latitudes to the poles. That heat travels on atmospheric and oceanic currents. This figure nicely summarize this radiation balance:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AjGDk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AjGDk.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Figure from &lt;a href=&quot;https://www.meted.ucar.edu/search/details.php?id=24464&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; ©The COMET Program&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we consider that the heat transport depicted at the bottom of the figure remains the same. The only change in the energy budget would be from solar irradiation, and once they start warming the only way to release the additional heat and reach equilibrium would be trough infrared radiation (black body radiation).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The poles receive zero energy on the equinox and the winter solstice and &lt;a href=&quot;http://www.applet-magic.com/insolation.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;12.64 kWh/m&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt; per day on the summer solstice&lt;/a&gt;. Therefore a rough yearly average would be 3.16 kWh/m&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt; per day. So, if we were locked on a summer solstice state you would receive four time more energy, and none if locked in a winter solstice state.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Summer solstice locked pole&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's consider the summer solstice case first. If we call &lt;span class=&quot;math-container&quot;&gt;$E_1$&lt;/span&gt; the current amount of outgoing radiation from the pole, and &lt;span class=&quot;math-container&quot;&gt;$T_1$&lt;/span&gt; the current temperature. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stefan–Boltzmann law&lt;/a&gt; states that&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$E_1 = \sigma T_1^4$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Analogously, if &lt;span class=&quot;math-container&quot;&gt;$E_2$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$T_2$&lt;/span&gt; represent the summer solstice locked state, you have &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$E_2 = \sigma T_2^4$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Considering that &lt;span class=&quot;math-container&quot;&gt;$E_2 = 4 E_1$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can write that&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$4 = \frac{T_2^4}{T_1^4}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$T_2 = \left(\frac{1}{4}\right)^4 T_1 = 1.41\, T_1$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore the temperature would increase 41%. It doesn't sounds much, but considering that the temperatures above are in Kelvin, it es a lot! In fact, &lt;strong&gt;with the current &lt;a href=&quot;https://en.wikipedia.org/wiki/North_Pole#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;mean temperature in the north pole of -16 °C&lt;/a&gt; (257K), it would go up to +89°C!! And the South pole would go from the &lt;a href=&quot;https://en.wikipedia.org/wiki/South_Pole#Climate_and_day_and_night&quot; rel=&quot;nofollow noreferrer&quot;&gt;current -49°C&lt;/a&gt; (224K) to +42°C.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This diverges from any posible reality because with 89°C at the north pole there would not be a net influx of energy from the equatorial latitudes as we are assuming. Instead, atmospheric and oceanic currents would take a lot of that heat down south and the temperature would equilibrarte at a much lower value.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that in the above calculation I've ignored the energy flux due to advection in atmospheric/oceanic currents. I did so because that flux is about five time smaller than the flux from solar radiation, so it won't change much the results and ignoring it simplifies the math. You can do the calculation considering those flows if you want.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Winter solstice locked pole&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case of a pole locked to a winter solstice. There would be no incoming solar radiation at all. Therefore, all incoming energy would be transported by currents from equatorial latitudes. In that way, we can see in the above figure that the north pole receives about 150 W/m&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt;, and the south pole about 100 W/m&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt;. The equilibrium temperature would be reached when they radiate the same amount. So, using &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stefan–Boltzmann law&lt;/a&gt; again we can do some rough calculations.&#xA;Let's call the south pole temperature &lt;span class=&quot;math-container&quot;&gt;$T_{SP}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$T_{NP}$&lt;/span&gt; for the north pole. Then:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$T_{SP} = \left(\frac{E_{SP}}{\sigma}\right)^{1/4} = \left(\frac{100 \,W/m^2}{5.67\times 10^{-8}}\right)^{1/4} = 205 K= -68°C$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And for the north pole&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$T_{NP} = \left(\frac{E_{NP}}{\sigma}\right)^{1/4} = \left(\frac{150 \,W/m^2}{5.67\times 10^{-8}}\right)^{1/4} = 227 K= -46°C$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But again, with such cold temperatures the actual inflow of energy would be grater and the equilibrium temperature would not be that extreme.&#xA;In any case, that condition would be favourable to the growth of a massive ice sheet in the corresponding polar area, in the same way I describe in &lt;a href=&quot;https://earthscience.stackexchange.com/questions/15158/what-would-happen-to-the-earth-if-there-were-no-seasons/15159#15159&quot;&gt;this question and answer&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a final thought. For this condition to happen in real life you would need something analogous to &lt;a href=&quot;https://en.wikipedia.org/wiki/Tidal_locking&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tidal locking&lt;/a&gt; to lock the period of &lt;a href=&quot;https://en.wikipedia.org/wiki/Axial_precession&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth's precession (currently about 26,000 years)&lt;/a&gt; to exactly one year. And don't know of any mechanism that could achieve that. &lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-09-27T04:25:38.457" LastActivityDate="2018-09-27T04:25:38.457" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15190" PostTypeId="2" ParentId="15175" CreationDate="2018-09-27T20:16:45.860" Score="2" Body="&lt;p&gt;Ozone can indeed absorb UV and infrared radiation. The UV part, plays an important role in protecting us from harmful radiation, and the infrared part makes it an effective greenhouse gas.&#xA;All gases absorb/emit radiation at multiple different and discrete wavelengths. That's know since the early 19th century when the &lt;a href=&quot;http://Fraunhofer%20lines&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fraunhofer lines&lt;/a&gt; where observed. The wavelengths can change depending on ionization and other factors. But in this case,I don't think there is any change in the absorption wavelengths between stratospheric and tropospheric ozone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have information about such phenomena, please provide documentation. However, my guess is that in different situations studies might mention the absorption wavelengths that are relevant to the case, but that doesn't mean that it doesn't absorb in other wavelengths too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In particular, close to the Earth's surface there is plenty of infrared radiation, and very little UV radiation. Therefore, ozone might absorb more energy in the infrared. The oposite happen in the stratosphere, where it probably absorbs more energy in the UV bands. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;UV absorption bands are the most known for Ozone, but as I said it has infrared absorption bands too. You can see those bands in the following infrared spectrum obtained from &lt;a href=&quot;https://webbook.nist.gov/cgi/cbook.cgi?ID=C10028156&amp;amp;Units=SI&amp;amp;Mask=80#IR-Spec&quot; rel=&quot;nofollow noreferrer&quot;&gt;NIST&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/F47Ky.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/F47Ky.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-09-27T21:32:05.973" LastActivityDate="2018-09-27T21:32:05.973" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15191" PostTypeId="2" ParentId="14666" CreationDate="2018-09-27T23:42:38.560" Score="7" Body="&lt;p&gt;This is not meant to be a comprehensive answer:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sometimes the easiest way to calculate the velocity of an ocean current is to take the published transport of the current and divide by the total depth of the current. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For instance, for the Agulhas Current, you can take Figure 2 from &lt;a href=&quot;https://doi.org/10.1029/2008JC004954&quot; rel=&quot;noreferrer&quot;&gt;Casal et al. (2009)&lt;/a&gt; (below) and extract the velocities based on the depth of each area. Also in their Figure 6, there are several vertical sections of velocity across the current.   &lt;a href=&quot;https://i.stack.imgur.com/sOMmh.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sOMmh.jpg&quot; alt=&quot;Casal et al&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, you can obtain vertical sections of velocity for the same current (Agulhas) in earlier publications: &lt;a href=&quot;https://doi.org/10.1007/s10872-005-0057-8&quot; rel=&quot;noreferrer&quot;&gt;Bryden et al. 2005&lt;/a&gt; (Figure 8 and 9). Or in newer publications: &lt;a href=&quot;https://www.nature.com/articles/nature19853&quot; rel=&quot;noreferrer&quot;&gt;Beal &amp;amp; Elipot (2016)&lt;/a&gt;.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/rlglD.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rlglD.jpg&quot; alt=&quot;Beal &amp;amp; Elipot&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main issue is that you will need to do a bit of digging around for each of the currents you list.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2018-09-28T00:30:22.560" LastActivityDate="2018-09-28T00:30:22.560" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15193" PostTypeId="1" CreationDate="2018-09-28T07:57:52.347" Score="4" ViewCount="166" Body="&lt;p&gt;I am wondering if anybody has an idea about the difference between regional climate models and numerical weather prediction models that are run at the same domain. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have a basic idea that the numerical weather prediction models can be run at much higher resolution and due to the time stepping and CFL schemes, it is not always possible to run them for a long time. So I have a general query and I want to infer about the time stepping and CFL criteria used in an RCM and a NWP model. Are they different or they both are similar, it's just that an RCM is run at coarser resolution?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit:&#xA;I want to know if it is possible to get a climate model from a generic NWP model. I have seen the CWRF documentation which illustrates its highlights and mentions some different physical parameterizations corresponding to different processes. I realized that the convergence of model solution is more important even if the time stepping allows to get a long time run. I still have confusions about the new schemes used in CWRF, do they neglect subgrid scale processes like the other climate models? Why are these necessary to be implemented? Here, I also saw the mentioned description about CMM5 but I have the same doubts here. I want to know about the physical parameterizations and numerical schemes used in unified models and how are they different from that of a generic NWP model. &lt;/p&gt;&#xA;" OwnerUserId="11162" LastEditorUserId="11162" LastEditDate="2018-10-07T15:48:28.573" LastActivityDate="2018-10-16T17:12:32.017" Title="Conversion of an NWP model into climate model" Tags="|atmosphere-modelling|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="15194" PostTypeId="1" AcceptedAnswerId="15201" CreationDate="2018-09-28T10:30:34.430" Score="5" ViewCount="2091" Body="&lt;p&gt;I'm studying flow velocities in a small river. I have a lot of data of average flow velocities in cross sections throughout the entire catchment. And I know the river develop a stream velocity profile per cross section (see below).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZflhS.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZflhS.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;Now I'm also interested in the maximum flow velocity in a certain cross section. So I'm looking for a way to calculate the maximum velocity from the average velocity. Is there some kind of formula or method to do this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any help is appreciated.&lt;/p&gt;&#xA;" OwnerUserId="10681" LastActivityDate="2018-10-01T15:24:55.703" Title="Rivers - How to calculate maximum velocity from average velocity in a cross section" Tags="|hydrology|rivers|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15196" PostTypeId="1" CreationDate="2018-09-28T13:49:43.910" Score="1" ViewCount="50" Body="&lt;p&gt;Lightning produced NO&lt;span class=&quot;math-container&quot;&gt;$_{x}$&lt;/span&gt; (emitted as NO but quickly converted to NO&lt;span class=&quot;math-container&quot;&gt;$_{2}$&lt;/span&gt;) can be one of the major sources of atmospheric NO&lt;span class=&quot;math-container&quot;&gt;$_{x}$&lt;/span&gt; in the tropics &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S1352231001005532&quot; rel=&quot;nofollow noreferrer&quot;&gt;[1]&lt;/a&gt;. Estimates of emissions per flash range from 10 - 600 moles NO per flash &lt;a href=&quot;https://www.atmos-chem-phys.net/14/3277/2014/acp-14-3277-2014.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;[2]&lt;/a&gt;. I have 2 questions about this phenomenon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) What is the exact location where the lightning NO is emitted? Is it in the cloud? Is it over the whole range of the lightning strike? Is there a difference in location between the IC (intra-cloud) and CG (cloud-to-ground) flashes &lt;a href=&quot;https://www.atmos-chem-phys.net/7/3823/2007/acp-7-3823-2007.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;[3]&lt;/a&gt;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) What percentage of the total 2 to 20 Tg N yr&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt; actually ends up in the atmospheric boundary layer where it can be harmful as air pollutant or precursor of surface ozone?&lt;/p&gt;&#xA;" OwnerUserId="13896" LastActivityDate="2018-09-28T13:49:43.910" Title="To what extent does lightning produced NOx end up in the atmopsheric boundary layer?" Tags="|atmospheric-chemistry|air-pollution|lightning|" AnswerCount="0" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15199" PostTypeId="1" CreationDate="2018-09-28T21:37:01.677" Score="1" ViewCount="32" Body="&lt;p&gt;It took a lot of algae shells to make a chalk deposit, and one finds fossils of bigger organisms in them, and the flints/cherts where silicates ?condensed? during lithification. But where did the non-shell parts of the coccoliths go? Did currents separate the calcite from the organics? If they decomposed in place, didn't that leave the organic carbon of the decomposers? Was it fluid enough to squeeze out during lithification? Is this happening somewhere currently?&lt;/p&gt;&#xA;" OwnerUserId="2639" LastActivityDate="2018-09-28T21:37:01.677" Title="Where did the other parts of coccoliths go, if not in chalk?" Tags="|carbonate|chalk|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15201" PostTypeId="2" ParentId="15194" CreationDate="2018-09-28T23:19:52.890" Score="3" Body="&lt;p&gt;The velocity profile that is shown is parabolic. It is characteristic of &lt;a href=&quot;https://en.wikipedia.org/wiki/Laminar_flow&quot; rel=&quot;nofollow noreferrer&quot;&gt;laminar flow&lt;/a&gt; in tubes or channels. A development of the equation is shown &lt;a href=&quot;https://ocw.mit.edu/courses/earth-atmospheric-and-planetary-sciences/12-090-introduction-to-fluid-motions-sediment-transport-and-current-generated-sedimentary-structures-fall-2006/course-textbook/ch4.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;in this link&lt;/a&gt;. An exposition about flow in open channels is &lt;a href=&quot;https://www.lth.se/fileadmin/tvrl/files/vvr090/lecture7_open_channel.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;at this link&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The maximum velocity over the entire profile is at the surface (see Equation 4.7 and statement 17 in the first reference). The maximum velocity at an other range of positions as measured vertically from the bottom of the stream is always found at the top of the range (i.e. at the point closest to the surface of the stream).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's propose a velocity profile from the bottom to top of the channel as this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ v(z) = Cz^2 $$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This satisfies the boundary condition that &lt;span class=&quot;math-container&quot;&gt;$v(0) = 0$&lt;/span&gt; at the bottom of the channel. The parameter &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; is found by taking one additional measurement anywhere in the stream. With this function, we find the average velocity over a range of positions &lt;span class=&quot;math-container&quot;&gt;$zo$&lt;/span&gt; to &lt;span class=&quot;math-container&quot;&gt;$zt$&lt;/span&gt; is an integral over the parabolic profile ...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ &amp;lt;v&amp;gt; = \frac{\int_{zo}^{zt} v(z) dz}{zt - zo} = \frac{C}{(zt - zo)} \int_{zo}^{zt} z^2 dz = \frac{C\left(zt^3 - zo^3\right)}{3\left(zt - zo\right)} $$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An alternative way then to find &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; when given an average velocity over a range of distances is to use this expression.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A distinction is required to understand the average velocity expressed above. An alternative view of average velocity is from measuring at a set of points over a range &lt;span class=&quot;math-container&quot;&gt;$zo$&lt;/span&gt; to &lt;span class=&quot;math-container&quot;&gt;$zt$&lt;/span&gt; and then averaging the measured values. This &lt;em&gt;measured average&lt;/em&gt; has the expression&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ &amp;lt;v&amp;gt;_m = \frac{1}{N} \sum {v_j} $$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With &lt;span class=&quot;math-container&quot;&gt;$H$&lt;/span&gt; as the height of the channel, in the limit that &lt;span class=&quot;math-container&quot;&gt;$zt - zo &amp;lt;&amp;lt; H$&lt;/span&gt;, we can assume &lt;span class=&quot;math-container&quot;&gt;$&amp;lt;v&amp;gt; \approx &amp;lt;v&amp;gt;_m$&lt;/span&gt;. Otherwise, the better approach is to use a one-point method with &lt;span class=&quot;math-container&quot;&gt;$v$&lt;/span&gt; at &lt;span class=&quot;math-container&quot;&gt;$z$&lt;/span&gt; and the source equation for the profile.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, consider when you have multiple measurements at different positions where the positions are not differentiated but the velocities are differentiated. One approach here is to average the velocities and use any one value to the profile for &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt;. The better method however will use non-linear regression method to fit data. By example, consider this hypothetical &quot;measured&quot; data set generated using &lt;span class=&quot;math-container&quot;&gt;$v = 4 z^2$&lt;/span&gt; as its base.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;z=1, v = 3, 4, 5, 6&lt;/p&gt;&#xA;&#xA;&lt;p&gt;z=2, v = 14, 15, 16, 17&lt;/p&gt;&#xA;&#xA;&lt;p&gt;z=3, v = 32, 33, 35, 45&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A plot of the data and a non-linearized regression fit to &lt;span class=&quot;math-container&quot;&gt;$v = Cz^2$&lt;/span&gt; is shown below. The result is &lt;span class=&quot;math-container&quot;&gt;$C = 4.0 \pm 0.2$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mv1D9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mv1D9.png&quot; alt=&quot;velocity profile fit&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13534" LastEditorUserId="13534" LastEditDate="2018-10-01T15:24:55.703" LastActivityDate="2018-10-01T15:24:55.703" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15206" PostTypeId="1" CreationDate="2018-09-29T17:37:03.690" Score="1" ViewCount="279" Body="&lt;p&gt;I would like to create a 3d unstructured grid based on data points with xyz and property.  Can Python do this and what tools?&lt;br&gt;&#xA; My question is quite generic but i can provide more details: the data has easting and northing in UTM coordinates, elevation in masl, and a property value that i define based on soil type which i assign a permeability value or a particle size (ultimately, i would like to interpolate both).  the dataset has about 5000 points for approx 1000 boreholes, so 5 points on average per borehole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As each borehole has a different number of soil intervals, i think the best is to use an unstructred grid so that the top of soil elevation are respected at each borehole&#xA;thanks&#xA;f&lt;/p&gt;&#xA;" OwnerUserId="12516" LastEditorUserId="12516" LastEditDate="2018-09-30T14:04:05.943" LastActivityDate="2019-01-23T19:59:30.783" Title="python generate 3d unstructured grid" Tags="|geology|numerical-modelling|interpolation|" AnswerCount="0" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="15207" PostTypeId="1" CreationDate="2018-09-29T19:52:34.217" Score="3" ViewCount="175" Body="&lt;p&gt;&lt;strong&gt;Homework question&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Show that the absorption optical thickness of the atmosphere&#xA;  at pressure &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; (i.e., between &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; and the top of the atmosphere) as a function of the mixing ratio&#xA;  of the absorbing gas &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; and the absorption coefficient per unit mass &lt;span class=&quot;math-container&quot;&gt;${k}_{ν}$&lt;/span&gt; can be expressed as:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$τ = \frac{k_νrp}{g}$&lt;/span&gt;. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Assume &lt;span class=&quot;math-container&quot;&gt;$r ≪ 1$&lt;/span&gt; &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;(So we can approximate &lt;span class=&quot;math-container&quot;&gt;$r ≃ \frac{ρ_a}{ρ}$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$ρ_a$&lt;/span&gt; is the density of the&#xA;  absorbing gas), and that &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$k_ν$&lt;/span&gt; are vertically uniform, and assume that there is no scattering. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Has the anthropogenic increase in &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; shifted the emission level to higher or lower altitude? Prove your answer.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Attempt&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given the equation &lt;span class=&quot;math-container&quot;&gt;$τ = \frac{k_νrp}{g}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I took the &lt;span class=&quot;math-container&quot;&gt;$ln(\tau) = ln(\frac{k_νrp}{g})$&lt;/span&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$ln(\tau) = ln(k_ν) + ln(r) + ln(p) - ln(g)$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$dln(\tau) = dln(k_ν) + dln(r) + dln(p) - dln(g)$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\frac{dln\tau}{\tau} = \frac{dlnk_ν}{k_v} + \frac{dlnr}{r} + \frac{dlnp}{p} - \frac{dlng}{g}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We will assume that &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$k_v$&lt;/span&gt; are constant, so disregard for a moment here.  It is a battle between the mixing ratio &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\frac{dln\tau}{\tau} = \frac{dlnr}{r} + \frac{dlnp}{p}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we want to know if peak &lt;span class=&quot;math-container&quot;&gt;$\tau$&lt;/span&gt; moves up or down, I say that &lt;span class=&quot;math-container&quot;&gt;$\tau$&lt;/span&gt; is constant.  If I increase the mixing ratio &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; (increase &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; concentration in atmosphere), pressure must decrease in order to keep &lt;span class=&quot;math-container&quot;&gt;$\tau$&lt;/span&gt; constant, and decreased pressure means moving up in altitude.  I conclude that increasing &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; concentrations shifted the emission level to a higher altitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Help&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am unsure how to arrive at the initial given equation.  My understanding of &lt;span class=&quot;math-container&quot;&gt;$\tau$&lt;/span&gt; is minimal, and I just see too many variations and integrals concerning &lt;span class=&quot;math-container&quot;&gt;$\tau$&lt;/span&gt;.  I see how the Ideal Gas Law and the Hypsometric Relation will be used to replace variables &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$ρ = ρ_o*e^\frac{-z}{H}$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$H = \frac{RT}{g}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$P = ρRT$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(just trying to work backwards and piece the puzzle together, but the vision is unclear), but what was the original equation that was used, and ultimately--why?&lt;/p&gt;&#xA;" OwnerUserId="13928" LastEditorUserId="595" LastEditDate="2018-09-30T09:43:02.680" LastActivityDate="2018-09-30T09:43:02.680" Title="Optical Thickness of the Atmosphere" Tags="|atmosphere|climate-change|homework|mathematics|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15209" PostTypeId="1" CreationDate="2018-09-30T01:31:19.100" Score="5" ViewCount="149" Body="&lt;p&gt;Measurements taken by the Curiosity rover have detected minute amounts of methane in the Martian atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was wondering, is it possible that greater amounts of methane are present beneath the surface, i.e. several meters below the Martian soil?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I ask as I wonder if the discovery of large amounts of methane in the Martian soil may provide evidence of past/present life.&lt;/p&gt;&#xA;" OwnerUserId="13647" LastEditorUserId="13647" LastEditDate="2018-09-30T09:26:55.787" LastActivityDate="2018-10-13T09:09:07.017" Title="Methane in Martian Soil" Tags="|mars|methane|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15210" PostTypeId="1" CreationDate="2018-09-30T06:20:27.187" Score="1" ViewCount="53" Body="&lt;p&gt;This terminology is quite confusing to me.  Are effective temperature, emission temperature, and effective emission temperature the same thing?  Where does this occur, at the surface, or at some height in the atmosphere?&lt;/p&gt;&#xA;" OwnerUserId="13928" LastEditorUserId="13928" LastEditDate="2018-09-30T06:42:40.917" LastActivityDate="2018-09-30T06:42:40.917" Title="Clarification: Effective temperature, emission temperature, and effective emission temperature" Tags="|atmosphere|climate-change|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15212" PostTypeId="1" AcceptedAnswerId="15226" CreationDate="2018-09-30T20:24:35.610" Score="2" ViewCount="94" Body="&lt;p&gt;The following question was inspired by &lt;em&gt;Effective pressure or what is the effect of presssure?&lt;/em&gt;, which may be accessed here: &lt;a href=&quot;https://inside.mines.edu/UserFiles/File/CRA/2005/hoffman_etc_tle200612_effective_pressure.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://inside.mines.edu/UserFiles/File/CRA/2005/hoffman_etc_tle200612_effective_pressure.pdf&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is this: what exactly is &lt;strong&gt;pore pressure&lt;/strong&gt;? Is it different from pore fluid pressure? An article or some type of visualization for an answer would be outstanding.  &lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2018-10-02T20:33:29.287" Title="Basic petrophysics" Tags="|petrology|seismic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15213" PostTypeId="1" CreationDate="2018-09-30T21:43:14.890" Score="1" ViewCount="60" Body="&lt;p&gt;I'm performing an educational experiment on the piezoelectric effect in quartz, and it would be useful for me to know its electric permittivity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've been told that the quartz sample that I have is a cut 5° about one of its crystallographic axis, but it's not specified which axis that is. Is that ambiguity critical to the possibility of extracting the information I need from a table?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If there's any other information you need, please let me know in a comment. Thank you very much.&lt;/p&gt;&#xA;" OwnerUserId="13934" LastEditorUserId="2470" LastEditDate="2018-10-01T09:13:35.950" LastActivityDate="2018-10-01T09:13:35.950" Title="Electric permittivity of quartz" Tags="|crystals|electromagnetism|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15214" PostTypeId="1" AcceptedAnswerId="15280" CreationDate="2018-10-01T00:37:17.883" Score="9" ViewCount="146" Body="&lt;p&gt;How much of arctic ice is from snow fall versus frozen sea water? I presume arctic ice comes from both sources.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a way to tell how the ice was formed? In other words, if you made a core through the arctic ice cap, could you tell how much of the core was from snow versus frozen sea water? What's the difference?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastEditorUserId="11908" LastEditDate="2019-03-13T05:17:09.607" LastActivityDate="2019-03-13T05:17:09.607" Title="How much of arctic ice is from snow fall versus frozen sea water?" Tags="|oceanography|snow|sea-ice|arctic|cryosphere|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15216" PostTypeId="2" ParentId="15120" CreationDate="2018-10-01T13:28:46.573" Score="1" Body="&lt;p&gt;Under normal conditions a layer of gravel has more hydraulic conductivity in comparison to sand. Check this &lt;a href=&quot;http://structx.com/Soil_Properties_007.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;table with a hydraulic conductivity k per soiltype&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The storage in the aquifer with gravel will be larger than in sand if the same thickness is used. Otherwise you should take the thickness into account as well (= Transmissivity: kD).&lt;/p&gt;&#xA;" OwnerUserId="10681" LastEditorUserId="10681" LastEditDate="2018-10-03T18:49:40.800" LastActivityDate="2018-10-03T18:49:40.800" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15218" PostTypeId="2" ParentId="6532" CreationDate="2018-10-01T17:38:06.810" Score="2" Body="&lt;p&gt;2.5 million years is more than enough time for things to change drastically some places, in New Zealand there are mountains whose sediments were seafloor ooze a million years ago, but Africa is not usually one of them. Africa's geology is normally far too stable to show major changes on that short a timescale. In the normal course of things a given position in a cave system becomes shallower as time goes on due to surface erosion. What I can find on the &lt;a href=&quot;https://ujcontent.uj.ac.za/vital/access/services/Download/uj:12824/CONTENT1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Monte Christo Formation&lt;/a&gt; that holds the &lt;a href=&quot;https://en.wikipedia.org/wiki/Rising_Star_Cave&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rising Star Cave&lt;/a&gt; and the surface survey &lt;a href=&quot;http://dspace.nwu.ac.za/bitstream/handle/10394/10858/Koch_J_Chapter_3.pdf?sequence=4&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; suggests that there have been no major deposition events since the caves were formed, this would suggest that in fact the fossils were even deeper under ground when they were deposited.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is however possible that there was a transient hole in the roof of the cave that has since filled with redeposited minerals and is no longer evident, such are not unheard of in karst terrain and would have supplied light to great depths. The bones may also have originated closer to the cave entrance and been swept deeper into the system by flooding at a later date.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="10735" LastEditDate="2018-10-01T17:44:33.947" LastActivityDate="2018-10-01T17:44:33.947" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15219" PostTypeId="2" ParentId="2178" CreationDate="2018-10-01T18:01:00.570" Score="1" Body="&lt;p&gt;According to the below albedo rating diagram (percentage is reflection of incident radiation) cumulus cloud is the greater total spectrum reflector so it will reflect more UV that equivalent stratus formations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/68Q37.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/68Q37.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do note that water vapour does however absorb the vast majority of UV (≈100nm) that it intercepts as we can see in this diagram:&lt;a href=&quot;https://i.stack.imgur.com/rV9Jg.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rV9Jg.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So overall cloud UV reflectance will be quite low.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="10735" LastEditDate="2018-10-02T12:28:16.253" LastActivityDate="2018-10-02T12:28:16.253" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15221" PostTypeId="1" CreationDate="2018-10-02T06:59:11.590" Score="0" ViewCount="228" Body="&lt;p&gt;We recently had an earthquake in Bali (August 5th 2018), then in Palu, Indonesia (October 1st 2018).&#xA;&lt;a href=&quot;https://i.stack.imgur.com/yl2AB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yl2AB.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Considering the distance and time between Bali and Palu, is it more likely that it will be near Philipines or it is as likely anywhere else?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How likely is that the next big earthquake (and tsunami) will hit the Philippines again?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="13941" LastEditorUserId="20" LastEditDate="2018-10-08T04:34:31.600" LastActivityDate="2018-10-13T09:16:46.577" Title="How likely is that next big earthquake (and tsunami) will hit Philippines again?" Tags="|earthquakes|plate-tectonics|tsunami|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15222" PostTypeId="1" AcceptedAnswerId="15232" CreationDate="2018-10-02T09:39:12.637" Score="10" ViewCount="529" Body="&lt;p&gt;This &lt;a href=&quot;https://outdoors.stackexchange.com/a/15158/12619&quot;&gt;answer&lt;/a&gt; quotes &lt;a href=&quot;http://cameronrobbins.com/mount-jim/&quot; rel=&quot;noreferrer&quot;&gt;this blogpost&lt;/a&gt; as an example of a magnetic anomaly:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Basalt formation, “Mt. Jim”, in remote north-east Victoria, Australia, has a magnetic anomaly -20 degree magnetic compass variation - caused by a massive, yet unknown, submerged object.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Is there really a verified magnetic anomaly in north-east Victoria, Australia of 20 degrees? If so, is there a naturally occurring phenomenon (e.g. large sub-surface ferromagnetic rock formation) that causes it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A link to some deviation map or other verifying, quantitative source is requested, thanks!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JzG1S.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JzG1S.jpg&quot; alt=&quot;Mt. Jim magnetic anomaly Victoria, Australia&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="11908" LastEditDate="2019-04-06T20:07:32.323" LastActivityDate="2019-04-06T20:07:32.323" Title="Is there a &quot;submerged object&quot; in Australia that causes a magnetic deviation of 20 degrees?" Tags="|geology|geophysics|geomagnetism|rock-magnetism|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15223" PostTypeId="2" ParentId="6532" CreationDate="2018-10-02T12:11:02.997" Score="0" Body="&lt;p&gt;From the &lt;a href=&quot;https://en.wikipedia.org/wiki/Rising_Star_Cave&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia article&lt;/a&gt; about the cave:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;A portion of the cave, used by the excavation team en route to the Dinaledi Chamber, is called &quot;Superman's Crawl&quot; because most people can fit through only by holding one arm tightly against the body and extending the other above the head, in the manner of Superman in flight.[2][5]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Superman Crawl opens into the &quot;Dragon's Back Chamber,&quot; which includes an approximately 15 m (49 foot) exposed climb up a ridge of a sharp-edged dolomite block that fell from the roof sometime in the distant past. This block is the so-called Dragon's Back, so named because the climbing route appears to progress from the tail to the head along the spiked spine of a mythical beast.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So probably the last two obstacles, the dragon's back crawl and the last steep section, weren't there. Likely they could have just walked across those before the ceiling fell in. And possibly there might have been an easier route into the cave that's now hidden under the rockpile.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This isn't an actual answer, but the quote was too long to fit into a comment.&lt;/p&gt;&#xA;" OwnerUserId="12787" LastActivityDate="2018-10-02T12:11:02.997" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15225" PostTypeId="1" CreationDate="2018-10-02T19:32:35.643" Score="1" ViewCount="41" Body="&lt;p&gt;I see some models described as simulating 'receiving water quality' and others as 'pollutant loading' models. &lt;strong&gt;What is the difference between loading and receiving models in this context?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am more familiar with the 'pollutant loading' term because of its more widespread use, e.g. predicting pollutant loads, Total Maximum Daily Loads, EMC * flow = load. In this sense, loading is the buildup of pollutants which will flow out of a given area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given that my description of loading sounds like 'edge of field' pollution estimates, e.g. the amount of pollutants leaving the field but not necessarily how much pollutant will arrive at a downstream outlet, would receiving water quality models be predicting the 'at the outlet' pollution? Or, what a point downstream will receive based on phenomenon upstream?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If my description of a receiving model is correct, it sounds like loading and receiving is somewhat a matter of perspective. If I model Delaware River Basin and estimate pollution flowing out of it, that's a loading model, but if I have a receiving model of the Delaware Bay, isn't that the same thing? Are receiving models more focused on simulating pollutant transformations and in-river processes?&lt;/p&gt;&#xA;" OwnerUserId="4789" LastActivityDate="2018-10-02T19:32:35.643" Title="What's the difference between &quot;loading&quot; and &quot;receiving&quot; in water quality modeling?" Tags="|hydrology|models|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15226" PostTypeId="2" ParentId="15212" CreationDate="2018-10-02T20:33:29.287" Score="3" Body="&lt;p&gt;The concept of &lt;strong&gt;pore pressure&lt;/strong&gt; is identical to the concept of &lt;strong&gt;pore fluid pressure&lt;/strong&gt;, as you identified yourself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The article rightfully identifies two pressure types: the confining pressure (those forces that try to compress the soil, like the weight of the overburden pushing on the soil) and the pore fluid pressure (the forces that resist compression; water, for example, is approximately an incompressible fluid, so it will resist the forces that try to squeeze it into a smaller shape. The pore fluid will thus be at hydrostatic pressure, but never more than that!).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Subtracting these two opposing forces gives what your article refers to as the differential stress. That formula, in words, is something like '&lt;em&gt;the possibility of the material to be packed tighter together&lt;/em&gt;, minus &lt;em&gt;the resistance of fluid to being packed tighter together&lt;/em&gt;'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This Wikipedia article can give some insight: &lt;a href=&quot;https://en.wikipedia.org/wiki/Effective_stress&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Effective_stress&lt;/a&gt; , this video does some simple calculations: &lt;a href=&quot;https://www.youtube.com/watch?v=chjEsWvLu5s&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=chjEsWvLu5s&lt;/a&gt; . Does that answer your question?&lt;/p&gt;&#xA;" OwnerUserId="12155" LastActivityDate="2018-10-02T20:33:29.287" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15228" PostTypeId="2" ParentId="15222" CreationDate="2018-10-02T22:26:00.813" Score="5" Body="&lt;p&gt;The Mount Jim in your map seem to be the one located at 36° 55' 17&quot; S and 147° 13' 01&quot; E. Although, magnetic anomalies are not mapped over the whole worlds, the &lt;a href=&quot;http://geomag.org/models/wdmam.html&quot; rel=&quot;noreferrer&quot;&gt;World Digital Magnetic Anomaly Map&lt;/a&gt; provides the best compilation, and there is good data around your area of interest.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've loaded the magnetic anomaly data of the &lt;a href=&quot;http://geomag.org/models/wdmam.html&quot; rel=&quot;noreferrer&quot;&gt;World Digital Magnetic Anomaly Map&lt;/a&gt;, and plot the location of Mt. Jim over it (red dot), for comparison, the same dot is shown over a satellite map. All in the following animated gif:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9CnXd.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9CnXd.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, it doesn't seem to be any specially significant anomaly around Mt. Jim. However, this data show the magnetic anomaly reduced at 5 km of elevation. Therefore, a very strong but localized anomaly might not show up here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One other thing that is estrange in your reference, is that a magnetic anomaly would not produce a consistent &quot;-20 degree magnetic compass variation&quot;. Instead, the magnitude and direction of the variation would strongly depend on how close and where are you relative to the anomaly.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-10-02T22:26:00.813" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15232" PostTypeId="2" ParentId="15222" CreationDate="2018-10-03T12:38:59.547" Score="6" Body="&lt;p&gt;I'll disagree with Camilo Rada's answer, and show that there is definitely a magnetic anomaly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We start with the &lt;a href=&quot;http://www.ga.gov.au/interactive-maps/#/theme/minerals/map/geophysics&quot; rel=&quot;noreferrer&quot;&gt;interactive geophysics map&lt;/a&gt; of Geoscience Australia, Australia's federal geoscience agency. Our region is this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2xdHX.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2xdHX.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's the same area with magnetic intensity layer turned on:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hgwEf.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hgwEf.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see a clear magnetic anomaly in this area, and it's actually much more widespread than noted on your map.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If so, is there a naturally occurring phenomenon…that causes it?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In general, answers to questions like these are &lt;strong&gt;yes&lt;/strong&gt;. But let's explore it further with the geological map of the area:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tE5qc.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tE5qc.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Overall, the rock type around is &quot;OSn&quot; and &quot;Os&quot;. According to the &lt;a href=&quot;http://pid.geoscience.gov.au/dataset/ga/74855&quot; rel=&quot;noreferrer&quot;&gt;legend&lt;/a&gt;, these are high grade metamorphic Ordovician and Silurian rocks, and neighbouring rocks are siliclastic which tells me they shouldn't be too magnetic (confirmed by the magnetic map). The area of Mt Jim has &quot;Dg&quot; (= Devonian granites) which might be slightly magnetic. But here's the thing you were looking for: &quot;Czb&quot;, which is short for Cenozoic basalt. And basalts are magnetic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to answer your question, the source for the magnetic anomaly isn't a &quot;submerged&quot; (buried would more appropriate here btw), but a &lt;strong&gt;basalt fully exposed on the surface&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Interestingly, the blog post mentions the presence of basalt, so it's not entirely clear why they claim that there's a &quot;massive, yet unknown, submerged object&quot;. Most probably there's simply more basalt, or its intrusive analogue: dolerite or gabbro. These targets are attractive for the mining industries. I would be surprised if it hasn't been drilled at some point by an exploration company, and then the underground cause of the anomaly would be very well known (but probably not publicly).&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-10-03T12:38:59.547" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="15235" PostTypeId="2" ParentId="15049" CreationDate="2018-10-03T21:36:49.520" Score="1" Body="&lt;p&gt;I suspect the answer is no. The reason is that underwater constructions typically are supposed to be air- and water-tight, and to have strength enough to resist pressure differences. Biorock looks like it is naturally porous, so it would not be particularly good at holding water out. While the compression strength is like concrete, you &lt;em&gt;really&lt;/em&gt; want to guarantee the solidity if you have humans in it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically, risk and uncertainty is a cost too. It is often worth paying extra to know what a structure can handle. So hence it might just be easier to use underwater concrete, where there is likely far more standardised quality. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Still, biorock is cool and will presumably in due time be well understood enough to compete with a lot of materials and methods.)&lt;/p&gt;&#xA;" OwnerUserId="12421" LastActivityDate="2018-10-03T21:36:49.520" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15236" PostTypeId="1" AcceptedAnswerId="15253" CreationDate="2018-10-03T22:31:25.517" Score="0" ViewCount="711" Body="&lt;p&gt;With respect to climate change, will the changes in albedos due to clear skies and overcast skies have the greatest impact on incoming solar radiation over ocean, sea ice, or land?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My thoughts:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On a scale, the ocean has the lowest albedo, nearing on 0, land is much higher with an average of 0.3, and sea ice has the greatest with average of 0.6.  Since the oceans absorb almost all the incoming radiation, an increase in cloud cover will greatly change the albedo, since clouds tend toward 1, and much less energy will be absorbed.  Looking at sea ice, it already reflects 60%, adding clouds with similar albedos, the change won’t be much.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: I picked these crude numbers from the internet for sake of argument.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is my reasoning correct, or am I missing piece of puzzle?  &lt;/p&gt;&#xA;" OwnerUserId="13928" LastActivityDate="2018-10-06T16:15:15.450" Title="Over which surface will the albedo changes due to clear and overcast skies have the greatest impact?" Tags="|atmosphere|climate-change|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15239" PostTypeId="1" CreationDate="2018-10-04T19:28:43.850" Score="0" ViewCount="720" Body="&lt;p&gt;What is the difference between levees and dykes in terms of river embankment and also which type of materials are generally used in making river embankment ? &lt;/p&gt;&#xA;" OwnerUserId="13960" LastActivityDate="2018-10-05T06:36:06.910" Title="Material used in river embankment and difference between levees and dykes" Tags="|rivers|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15240" PostTypeId="2" ParentId="3165" CreationDate="2018-10-04T19:54:16.740" Score="0" Body="&lt;p&gt;If you have permafrost and an ice sheet begins to form on the land, it insulates the ground from the super cold air.  Geological heat should then begin to melt the permafrost slowly from the bottom up.  If the ice sheet persists for a long time, and is thick enough, like over East Antarctica, the permafrost should disappear until there is water at the bottom of the ice sheet.  Any methane produced by rotting vegetation or venting coal, oil or shale in deeper layers should combine with this water, especially since the pressure is great at the bottom of an ice sheet, and form a layer of clathrate.  Clathrates, if enough pressure exists can form up to 30 degrees C.  The temperature at the bottom of a thick ice sheet should be at the melting temperature of ice which at such depths is a couple of degrees below zero.&lt;/p&gt;&#xA;" OwnerUserId="13961" LastActivityDate="2018-10-04T19:54:16.740" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15241" PostTypeId="2" ParentId="12740" CreationDate="2018-10-04T22:54:38.033" Score="-1" Body="&lt;p&gt;Thunder 1 mile away-117 dB&#xA;Thunder 1/2 mile away-121 dB&#xA;Lightning strike just meters away from you-125 dB&lt;/p&gt;&#xA;" OwnerUserId="13962" LastActivityDate="2018-10-04T22:54:38.033" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15242" PostTypeId="1" CreationDate="2018-10-05T00:17:32.100" Score="7" ViewCount="166" Body="&lt;p&gt;Let's say my country is very environment conscious, has lots of trees and animals, protects the forest, uses clean/green energy, and has all kinds of environment friendly policies you can imagine. Will my country be safe from climate change? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or will that be useless when other countries don't take those measures, because we all share the same atmosphere?&lt;/p&gt;&#xA;" OwnerUserId="13963" LastEditorUserId="13963" LastEditDate="2021-05-29T16:45:53.610" LastActivityDate="2021-05-30T03:46:04.613" Title="Will a country that cares for its environment be affected by climate change due to other countries' pollution?" Tags="|atmosphere|climate-change|environmental-protection|pollution|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15243" PostTypeId="2" ParentId="11920" CreationDate="2018-10-05T01:20:56.913" Score="2" Body="&lt;p&gt;Its  &lt;a href=&quot;https://en.wikipedia.org/wiki/Tabulata&quot; rel=&quot;nofollow noreferrer&quot;&gt;tabulate coral fossil&lt;/a&gt; &lt;a href=&quot;http://www.thefossilforum.com/index.php?/topic/39199-paleozoic-chert-gravel-fossils-from-bogue-chitto-river-washington-parish-citronelle-formation/&quot; rel=&quot;nofollow noreferrer&quot;&gt;bogue chitto river&lt;/a&gt; is full of them&lt;/p&gt;&#xA;" OwnerUserId="13964" LastEditorUserId="2470" LastEditDate="2018-10-05T09:04:49.140" LastActivityDate="2018-10-05T09:04:49.140" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15244" PostTypeId="2" ParentId="15242" CreationDate="2018-10-05T05:10:05.897" Score="8" Body="&lt;p&gt;The main driver for anthropogenic climate change is carbon dioxide because it is very long-lived and hence relatively evenly distributed within the atmosphere. And even if you'd somehow manage to keep reduced levels of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; in your country's atmosphere, you'd still be affected by large-scale weather changes. So yes, your country would be affected just like any other country.&lt;/p&gt;&#xA;&lt;p&gt;Of course other benefits from climate-friendly policies, such as better air quality due to reduced combustion or better public transport due to investments in that sector, have a stronger local impact.&lt;/p&gt;&#xA;" OwnerUserId="681" LastEditorUserId="18990" LastEditDate="2021-05-30T03:46:04.613" LastActivityDate="2021-05-30T03:46:04.613" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15245" PostTypeId="2" ParentId="15239" CreationDate="2018-10-05T06:29:28.523" Score="3" Body="&lt;p&gt;Generally, the terms are used somewhat interchangeably. However, a levee can be formed along a river or ephemeral channel due to natural causes. Mainly: flooding of the river/channel and subsequent deposition of suspended material on its banks. In case of a river: as this occurs on the sides of the river where the flowing water has the least energy, it mainly carries fine material such as fine sand, silt and clay. A dyke, on the other hand is often man made and can consist of numerous materials. In the Netherlands for instance, it is often made of various components of sand, clay and peat.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nPbJx.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nPbJx.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As the description in the image is dutch, the yellow parts are sandy materials, the brown/reddish are clayey materials and the orange/pink materials are peaty or clayey. You will often find peaty and clayey material on the outer parts of a dyke. These materials conduct less water than sand and serve as a first protective layer. In the Netherlands, the core is often made of sand, as the stability and geotechnical behaviour of sands are less influenced by water than those of clay. Clays shrink and swell as a result of water content, in extensive drought this may cause clays to crack and dykes to be damaged. Additionally, sands are more easily drained than clays, as a result of their bigger pores.&lt;br /&gt;&#xA;Sources:&#xA;Deltares&lt;/p&gt;&#xA;" OwnerUserId="13870" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-10-05T06:36:06.910" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15246" PostTypeId="2" ParentId="15242" CreationDate="2018-10-05T09:25:36.573" Score="5" Body="&lt;p&gt;If no-one does anything the result will be bad for everyone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If only a small number of countries (or global regions) do something and the rest of the planet does nothing the effect will be minimal or negligible of a global scale. The greater the number of regions doing something useful, the greater the effect and the benefit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For an impact to be made globally, a critical mass of regions needs to do something useful.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If your country does something and its neighbors don't, parts of your country may have better local conditions. It also depends on what other countries, elsewhere are doing. We are all in a canoe being moved by a strong current. We need everyone to paddle to get us to safety, not just a small number of people paddling.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2018-10-05T09:29:19.137" LastActivityDate="2018-10-05T09:29:19.137" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15249" PostTypeId="1" CreationDate="2018-10-06T04:54:27.257" Score="3" ViewCount="336" Body="&lt;p&gt;I found this on the side of the road in Oregon, i think it was left or forgoten about thats why it was left there but it has crystal pockets, multiple colors, some smooth sides, perfect circles and swirles. Ive never seen anything like it and hope some one can tell me more about its origins or classification. Rock? Meteroite? Plz help.   Ignore the bits of bright green in some of the photos , that is from a towel the rock was wiped with.&#xA;(&lt;a href=&quot;https://i.stack.imgur.com/JUkRT.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://i.stack.imgur.com/JUkRT.jpg&lt;/a&gt;)&lt;img src=&quot;https://i.stack.imgur.com/zaynC.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yqzeD.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OuvhK.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7xxC9.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aJSNu.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="13972" LastEditorUserId="13972" LastEditDate="2018-10-06T05:00:36.057" LastActivityDate="2018-11-09T18:02:40.517" Title="What kind of rock or stone is this? Where did it come from?" Tags="|meteorology|rocks|crystals|" AnswerCount="1" CommentCount="1" ClosedDate="2019-08-31T01:58:55.960" ContentLicense="CC BY-SA 4.0" />
  <row Id="15251" PostTypeId="1" CreationDate="2018-10-06T12:06:51.790" Score="2" ViewCount="130" Body="&lt;p&gt;I am using the ONI index to classify the years of high rainfall seasons (December–February) as El Niño, Neutral or La Niña. El Niño year is classified as one if the ONI index value is +0.5 °C for 5 consecutive overlapping seasons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question since my season in between two Gregorian calendar years, what seasons should I check for the +0.5 °C threshold? Is it the preceding seasons or should I check since the beginning of year. I ask this because I am interested in investigating how El Niño might affect rainfall during a season.&lt;/p&gt;&#xA;" OwnerUserId="8219" LastEditorUserId="725" LastEditDate="2018-10-13T08:35:15.603" LastActivityDate="2019-05-29T18:26:00.963" Title="How to classify the ENSO phase of a year?" Tags="|climate|oceanography|temperature|enso|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15253" PostTypeId="2" ParentId="15236" CreationDate="2018-10-06T16:15:15.450" Score="1" Body="&lt;p&gt;You should also consider that fresh snow atop the sea ice increases the albedo significantly. So the albedo for sea ice can fluctuate during a season. More clouds implies more precipitation, something we are seeing in a changing climate, so it’s fair to assume that changes in snow cover atop the sea ice will change as well. It may also make the change in seasonal albedo more dramatic, from sea ice to darker oceans. It depends on the weather patterns and the regions.&#xA; Also, first-year sea ice will have a lower albedo than multi-year ice that has does not melt each season - though in the Arctic is type of ice is now very rare. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If cloud cover increases over the oceans the albedo as seen from space will not change significantly, but again, the cloud types and heights will affect the albedo. But more cloud cover generally will trap more outgoing radiation enhancing the greenhouse effect. In a positive feedback loop. So, using you numbers, the albedo would increase, but the greenhouse effect would enhance, overall leading to a temperature increase. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Land cover also varies, mid latitude regions are likely to see more cloud cover and more intense storms with climate change. An increase in cloud cover would again lead to changes in the greenhouse effect. With the albedo likely increasing (dark greens of forests, fields, etc having lower albedos etc). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Overall your reasoning is sound, but it overlooks the effect cloud cover has on outgoing radiation from the Earth’s surface, more of which will be trapped and re-radiated by the extra water vapor. &lt;/p&gt;&#xA;" OwnerUserId="13135" LastActivityDate="2018-10-06T16:15:15.450" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15254" PostTypeId="1" AcceptedAnswerId="15265" CreationDate="2018-10-06T16:29:32.590" Score="2" ViewCount="93" Body="&lt;p&gt;If they used wind power to bring up cold water from far under the ocean in the day time and spray it on prevailing winds going into land, could they make it rain more in arid regions? What weather control can be done by bringing up cold water from the deep sea?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are some maths: If 1cm of rain for 1 kilometer is equivalent to a cubic meter of water. 1kwh can lift 1 cubic meter by 100 meters, so an average wind turbine can lift about 6 million square kilometers of 1cm rain every year. Australia is 8 million square kilometers, so 300 wind turbines can logically make Australia rainforest if clouds worked like rivers, without the salt problem?&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2018-10-08T01:14:53.873" LastActivityDate="2018-10-08T01:14:53.873" Title="Deep sea pumps that work on wind power, can they control the weather?" Tags="|meteorology|ocean|wind|evaporation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15256" PostTypeId="1" CreationDate="2018-10-06T20:36:53.890" Score="3" ViewCount="2367" Body="&lt;p&gt;Under the Wikipedia article Temperate climate &lt;a href=&quot;https://en.wikipedia.org/wiki/Temperate_climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Temperate climate&lt;/a&gt; in the introduction is describes:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In geography, the temperate or tepid climates of Earth occur in the&#xA;  middle latitudes, which span between the tropics and the polar regions&#xA;  of Earth.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/A0CMF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/A0CMF.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So by this sentence I take the temperate zone to be between the pink shaded area (the tropics, and the uppermost and lowermost broken lines (arctic and antarctic circles. This is simple enough.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then in the next paragraph it says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The temperate zones (latitudes from 35° to the polar circles at about&#xA;  66.5°, north and south) are where the widest seasonal changes occur, with most climates found in it having somewhat balanced influence from&#xA;  both the tropics and the poles.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Now it says that the temperate zones are between latitudes about 35 degrees from the equator to the polar circles. This is different than the earlier description, which said it was between the tropics and the polar circles, which is about +- 23.5 degrees to the polar circles, not 35 degrees.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A little lower it says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The north temperate zone extends from (approximately 23.5° north) to&#xA;  the Arctic Circle (approximately 66.5° north latitude). The south&#xA;  temperate zone extends from (approximately 23.5° south) to the&#xA;  Antarctic Circle (at approximately 66.5° south).&lt;br&gt; &lt;a href=&quot;https://en.wikipedia.org/wiki/Temperate_climate#Zones_and_climates&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zones and&#xA;  climates&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So now it's saying again the temperate zone is between the tropics (23.5 degrees latitude) to the polar circles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lower again it specifies that there is a suptropical zone, namely:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Subtropical climates are generally located between 23.5° and 35° north&#xA;  or south on the eastern or leeward sides of landmasses.&#xA;  &lt;a href=&quot;https://en.wikipedia.org/wiki/Temperate_climate#Humid_subtropical_climates&quot; rel=&quot;nofollow noreferrer&quot;&gt;Humid subtropical climates&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It's now specifying zones of the subtropics, but it doesn't change the fact that in the first instance it says the the temperate zone is between the tropics, +/- 23.5 degrees, and the polar circles, and then says the temperate zone is between 35 degrees to the polar circles, a definition which excludes the subtropics from the temperate zone. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which one is correct? Is there a contradiction here? If so, is it a mistake or something more subtle I don't understand?&lt;/p&gt;&#xA;" OwnerUserId="13979" LastActivityDate="2018-10-07T12:40:31.430" Title="Is this a contradiction in Wikipedia's definition of temperate zone?" Tags="|climate|geography|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15257" PostTypeId="2" ParentId="15256" CreationDate="2018-10-06T23:27:05.290" Score="1" Body="&lt;p&gt;“Subtropical climates are generally located between 23.5° and 35° north or south on the eastern or leeward sides of landmasses. Humid subtropical climates”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note this indicates that this is where subtropical climates are located on the eastern, or leeward side of landmasses. i.e. inland of western coastlines - think Louisiana, the Carolinas relative to the west coast for Humid Subtropical climates. The of deserts Africa (Sahara, Namib, Gobi) Central Asia and the Middle East, and Australia and Chile for dry subtropical climates. At the fringes of these areas and occasionally within the same latitude range is the Mediterranean climate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These areas would be within the 23.5 to 35 degrees of latitude range. They certainly are distinct from temperate climates which would be better described by moderate annual temperatures, broadleaf forests, high to average rainfall. In North America this isn’t a straight line across the continent, with Vancouver being warm and wet, and New York having harsh winters. You could argue that the cooler poleward areas of the temperate zone defined as between 35 and 66.5 are subarctic - this would reach farther south farther inland (Siberia, Central Canada, Northern Central Continental US, Mongolia).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do think the Wikipedia article contradicts itself and there needs to be a caveat in there that the presence of the medditeranean sea in the Northern Hemisphere changes the definition, and it does overlook the subtropical zone and should note that there are dry and humid subtropical zones who’s location is dependent on distance from the oceans, and the presence or  absence of warming coastal currents (I.e Gulf Stream). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The trouble with Wikipedia is that there are often generalizations made. The climate can vary on small spatial scales so labeling a climate as “the same” for a large swath of the earth is a generalization. Generalizations are needed, and there are finer classifications out there. &#xA;Including a swath of latitude that actually includes subtropical areas is a mistake, they are quite distinct and different climate zones. That needs to be edited to read “temperate zones are located between 35 and 66.5 degrees, poleward of the subtropical zones.” The article would need to link to the subtropical zones in that sentence as well to make it really clear too. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For your own information you may find the Köppen Climate Classification System interesting to look at, it visualizes my points, and can explain more than I can! &lt;a href=&quot;https://en.m.wikipedia.org/wiki/K%C3%B6ppen_climate_classification&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.m.wikipedia.org/wiki/Köppen_climate_classification&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13135" LastActivityDate="2018-10-06T23:27:05.290" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15259" PostTypeId="1" AcceptedAnswerId="15264" CreationDate="2018-10-07T03:22:18.890" Score="1" ViewCount="46" Body="&lt;p&gt;Analysis from the Curiosity Rover on Mars has detected tiny amounts of methane in the atmosphere. It is possible the origin of this detected methane  is from methanogens deep below the subsurface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is, how deep would we need to drill to reach a methane reservoir below the Martian soil? Once here, could this help us determine the origin of methane gas?&lt;/p&gt;&#xA;" OwnerUserId="13974" LastActivityDate="2018-10-07T13:48:56.427" Title="Methane Reservoir" Tags="|soil|mars|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15260" PostTypeId="1" CreationDate="2018-10-07T05:03:45.837" Score="2" ViewCount="87" Body="&lt;p&gt;I saw an article recently in the newspaper stating that a desalination plant near the seashore was causing the ground water to become saline. Usually I would expect that areas where saline water already sometimes intrudes would see this, but in this scenario the residents around the plant claimed that before the establishment of the plant the ground water had tasted &quot;as tender coconut&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If they are right then what may be cause for that saline water intrusion...&lt;/p&gt;&#xA;" OwnerUserId="13621" LastEditorUserId="6298" LastEditDate="2018-10-07T10:17:27.293" LastActivityDate="2020-10-28T18:50:36.777" Title="Do desalination plants affect the ground water table?" Tags="|hydrology|coastal|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15262" PostTypeId="2" ParentId="15256" CreationDate="2018-10-07T11:11:20.393" Score="2" Body="&lt;p&gt;Note that they say:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the temperate or tepid climates of Earth occur &lt;strong&gt;in&lt;/strong&gt; the middle latitudes&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The word &lt;strong&gt;in&lt;/strong&gt; can be used to convey that the first thing is only a part of the larger second thing... much as, for example, Texas is found IN the United States, or the preteen years are found in childhood. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But by including the additional further explanation of what the middle latitudes are directly after that, I agree it leans a reader towards your interpretation, and is ambiguous and likely confusing to others.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll try to make some minor adjustments to the article to hopefully alleviate any confusion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But in all honesty, it's probably better to not get overly caught up in such excessively precise categorizing.  I tend to believe that what one person, even one climatologist, might call temperate climates may well vary from what another one would classify them.&lt;br&gt;&#xA;For example, they can be based on temperature ranges, on prevailing wind patterns, on breaking into equally-sized regions (like &lt;a href=&quot;https://earthscience.stackexchange.com/questions/15256/is-this-a-contradiction-in-wikipedias-definition-of-temperate-zone#comment30727_15256&quot;&gt;Fred commented&lt;/a&gt;), etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Really, I'd think of the subtropics as sort of a blurry boundary between the tropics and the temperate zone... where the closer you get towards the Equator, the less seasonal variability and frequency of cold air intrusions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Indeed, even typical places well across into the &quot;official Tropics&quot; can see occasional years with some notable cold fronts, as happened in &lt;a href=&quot;https://havanatimes.org/?p=21070&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cuba&lt;/a&gt; and even &lt;a href=&quot;http://www.insidecostarica.com/dailynews/2010/december/15/costarica10121502.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Costa Rica&lt;/a&gt; in the winter of 2010.  So it's not like 23.5 is some magic physical boundary just because that's the northern extent of the sun's latitudinal cycle. &lt;/p&gt;&#xA;&#xA;&lt;hr&gt; &#xA;&#xA;&lt;p&gt;&lt;strong&gt;So the Wiki article as you read it appears to be saying the temperate climates are only 35° and 66.5°, only a subsection of the middle latitudes.  But honestly, exactly what you classify the boundaries as is sort of like arguing over &lt;a href=&quot;https://fivethirtyeight.com/tag/regionalism/&quot; rel=&quot;nofollow noreferrer&quot;&gt;which states are in the Midwest or Southern Southern US&lt;/a&gt; -- very unnecessary outside of very specific circumstances, and prone to at least occasional dispute probably even among experts.  Yes, a teacher or test may ask you to know their specific definition (whether of temperate boundaries or of which states are in the Midwest)... that's just part of life sometimes.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;But the real take-home idea towards understanding how the Earth and specifically climate/weather work is just that there's a Polar region which has very cold polar air basically year-round, a Tropical region which has very warm Tropical air year-round (outside of colder mountains!), and then a &quot;battle ground&quot; that shifts seasonally and even daily in between, altering the weather significantly in those locations.  And local factors like bodies of water and wind regimes can significantly shift regions into a large array of different expected weather&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-10-07T12:40:31.430" LastActivityDate="2018-10-07T12:40:31.430" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15263" PostTypeId="2" ParentId="15260" CreationDate="2018-10-07T13:35:59.273" Score="3" Body="&lt;p&gt;With &lt;a href=&quot;https://en.wikipedia.org/wiki/Desalination&quot; rel=&quot;nofollow noreferrer&quot;&gt;desalination plants&lt;/a&gt; the import thing to consider is from where such plants are taking water and where they are disposing of their waste.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The waste from desalination plants is either salt of very salty water. If the plant you are referring to is just dumping its waste on the ground nearby or into a nearby river or water channel it is possible that the salt in the discharge water from the plant will enter the ground water, making it salty.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Generally this should not happen and in most situation it does not. With desalination plants near the seashore, the waste water is discharged back into the sea, but far from the intake for the plant.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-10-07T13:35:59.273" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15264" PostTypeId="2" ParentId="15259" CreationDate="2018-10-07T13:48:56.427" Score="0" Body="&lt;p&gt;The &lt;a href=&quot;https://www.nasa.gov/mission_pages/mars/news/marsmethane.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;origin of methane on Mars is still unknown&lt;/a&gt;. Methanogens may be the source &amp;amp; if so would prove life exists on Mars, but no-one yet knows. As to the depth of the source of methane on Mars, this too is unknown.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The presence of methane in Mars' atmosphere could be of &lt;a href=&quot;http://exploration.esa.int/mars/46038-methane-on-mars/&quot; rel=&quot;nofollow noreferrer&quot;&gt;geological origin&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;One way to confirm the biological origin of methane would be to measure the isotope ratios of carbon and hydrogen, the two elements in methane. Life on Earth tends to use lighter isotopes, for example, more Carbon-12 than Carbon-13, because this requires less energy for bonding.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What is known is that the levels of methane in the atmosphere of Mars varies, but the variation is &lt;a href=&quot;https://www.space.com/32871-mars-methane-spike-curiosity-rover-mystery.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;not due to seasonal changes&lt;/a&gt;. The reason for the variation is still unknown.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-10-07T13:48:56.427" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15265" PostTypeId="2" ParentId="15254" CreationDate="2018-10-07T15:01:49.097" Score="2" Body="&lt;p&gt;In theory your idea is not bad,But it needs to be placed as far from land as possible this is to avoid the soil on land from being contaminated by saltwater.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So spraying saltwater into the air is not usefull for creating rain over land,But it can be used to cool the ocean and the planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Salt water spraying into the air can possibly help creating condensation nucleus,And help clouds to form and these clouds can shade the ocean and limit the heat absorption.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But this is not as simple as it sounds,Clouds tend to form more in the evening and night when the temparature drops and not as easy in the daytime when they are needed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clouds can limit the heating in the daytime,But they will trap or reflect heat in the night time,And then the positive effect is limited.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think it is best to use the hotter water from the surface of the ocean as it will evaporate faster and probably create clouds faster.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6258" LastEditDate="2018-10-07T16:55:52.287" LastActivityDate="2018-10-07T16:55:52.287" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15266" PostTypeId="1" CreationDate="2018-10-07T16:18:55.473" Score="0" ViewCount="746" Body="&lt;p&gt;What were CO2 levels in early and late Carboniferous, an what were mean levels? Who are the sources for these figures?&lt;/p&gt;&#xA;" OwnerUserId="13985" LastActivityDate="2018-10-13T08:39:13.480" Title="What were CO2 levels in Carboniferous?" Tags="|atmosphere|paleoclimatology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15267" PostTypeId="1" AcceptedAnswerId="17019" CreationDate="2018-10-07T21:12:19.103" Score="4" ViewCount="377" Body="&lt;p&gt;&lt;a href=&quot;https://math.stackexchange.com/questions/2084469/formula-to-calculate-the-maximum-ocean-level-rise-due-to-melting-ice&quot;&gt;This question&lt;/a&gt; on Maths SE asked how we might calculate the effect on sea level if all the world's ice (ie including the whole Antarctic ice sheet) were to melt. I posted an answer containing calculations suggesting - and this came as a surprise to me - that the rise in sea level would be up to about 40 metres more at high northern than at high southern latitudes.  The key &lt;em&gt;qualitative&lt;/em&gt; assumptions underlying this conclusion are:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Most of the world's ice is in the Antarctic ice sheet.&lt;/li&gt;&#xA;&lt;li&gt;The melting of all the world's ice and spread of the resulting&#xA;liquid water across the oceans would result in a shift in the&#xA;earth's centre of gravity.  Given 1 above, the shift would be&#xA;towards the north.   &lt;/li&gt;&#xA;&lt;li&gt;The shift in the earth's centre of gravity would not significantly&#xA;affect the position of the earth's land masses and ocean bed which&#xA;in this context can be regarded as a solid mass around which the&#xA;ocean water would position itself.&lt;/li&gt;&#xA;&lt;li&gt;The distribution of liquid water across the world's oceans, though&#xA;affected by other factors, is largely determined by the&#xA;gravitational force pulling it towards the earth's centre of&#xA;gravity.  Hence a northward shift in the centre of gravity would&#xA;pull a slightly larger proportion of the ocean water to the northern&#xA;hemisphere.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Are these assumptions broadly correct?&lt;/p&gt;&#xA;" OwnerUserId="13987" LastActivityDate="2019-05-22T22:14:42.513" Title="If all the world's ice were to melt, would this shift the earth's centre of gravity with consequential effects on sea levels?" Tags="|geophysics|sea-level|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15268" PostTypeId="1" CreationDate="2018-10-08T01:43:14.750" Score="6" ViewCount="75" Body="&lt;p&gt;How much does the Earth's center of mass move around relative to the most stationary objects on the surface?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm wondering whether the molten outer core has enough asymmetry to move the center of mass any appreciable amount from day to day.&lt;/p&gt;&#xA;" OwnerUserId="13988" LastActivityDate="2018-10-08T01:43:14.750" Title="How much does the Earth's center of mass move around?" Tags="|geophysics|core|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15269" PostTypeId="1" CreationDate="2018-10-08T09:49:37.123" Score="1" ViewCount="27" Body="&lt;p&gt;Is it possible to use &lt;a href=&quot;http://www.src.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CALPUFF&lt;/a&gt; in ISC-type single-station mode accounting for &quot;simple&quot; terrain effect (like in ISC)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can I set the orography out of &lt;a href=&quot;https://www.enviroware.com/calmet/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CALMET&lt;/a&gt;?&lt;/p&gt;&#xA;" OwnerUserId="13991" LastEditorUserId="725" LastEditDate="2018-10-13T09:10:33.827" LastActivityDate="2018-10-13T09:10:33.827" Title="CALPUFF dispersion model - orography" Tags="|atmosphere-modelling|software|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15270" PostTypeId="2" ParentId="15209" CreationDate="2018-10-08T14:21:21.330" Score="3" Body="&lt;p&gt;Studies shows there is Methane on Earth's Crust. The chemical form how it is stored is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Methane_clathrate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Methane Clathrate&lt;/a&gt;,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;a solid clathrate compound (more specifically, a clathrate hydrate)&#xA;in which a large amount of methane is trapped within a crystal&#xA;structure of water, forming a solid similar to&#xA;ice.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;(source:&lt;a href=&quot;https://en.wikipedia.org/wiki/Methane_clathrate&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;There are two main origins for this structures on &lt;a href=&quot;https://en.wikipedia.org/wiki/Crust_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth's Crust&lt;/a&gt;, mainly developed at the Oceanic Crust and stored some centimeters or meters below the water interface, after the sulfate reduction zone:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Microbial reduction of CO2.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Thermal decomposition of organic matter.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Both sources imply organic activity so possibly your question encloses that much-contested question about whether there was or not life on Mars in the past.&lt;/p&gt;&#xA;&lt;p&gt;Regardless there were or there were no life, &lt;em&gt;&lt;strong&gt;Lefèvre et al.(2009)&lt;/strong&gt;&lt;/em&gt;, clarify the occurrence and possible sources for methane on Mars from what we know with our current observation possibilities:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;The detection of methane on Mars has revived the possibility of past&#xA;or extinct life on this planet, despite the fact that an abiogenic&#xA;origin is thought to be equally plausible&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;They continue...&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;An intriguing aspect of the recent observations of methane on Mars is&#xA;that methane concentrations appear to be locally enhanced and change&#xA;with the seasons.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;And finally:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;We find that photochemistry as currently understood does not produce&#xA;measurable variations in methane concentrations, even in the case of a&#xA;current, local and episodic methane release. In contrast, we find that&#xA;&lt;strong&gt;the condensation–sublimation cycle of Mars’ carbon dioxide atmosphere&#xA;can generate large-scale methane variations differing from those&#xA;observed.&lt;/strong&gt;&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is still on debate and maybe someone can contribute quoting more recent articles, but the occurrence of Methane on Mars soil is measured, but &lt;strong&gt;this do not provide a proof that there was life on the planet.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;That condensation-sublimation cycle may lead to CH&lt;sub&gt;4&lt;/sub&gt; storage on soil around the poles, and form a kind of &amp;quot;Methane permafrost&amp;quot;, but formed for physical-chemical processes with no life interaction.&lt;/p&gt;&#xA;&lt;p&gt;Also &lt;strong&gt;asking for &amp;quot;large amounts of Methane on soil&amp;quot;, the answer possibly is no too&lt;/strong&gt;, because either Mars had life, Earth's organic activity has developed big Methane Clathrate deposits on Oceanic Crust because of the listed organic associated process.&lt;/p&gt;&#xA;&lt;p&gt;To recognize an organic origin of CH&lt;sub&gt;4&lt;/sub&gt;, isotopes of C of the samples should show low concentrations of heavy C&lt;sup&gt;14&lt;/sup&gt;, as life prefers to use lightweight ones: C&lt;sup&gt;13&lt;/sup&gt;/C&lt;sup&gt;12&lt;/sup&gt;&#xA;.&lt;/p&gt;&#xA;&lt;p&gt;That hypothetical biologic Methane would be found on the big depression that was supposed to have a water ocean. The latest formed on soil would have been liberated to the atmosphere at the death of the ocean (because of pressure decrease), but rests of organic CH&lt;sub&gt;4&lt;/sub&gt; could maybe be found drilling the zone.&lt;/p&gt;&#xA;&lt;p&gt;The new of past life occurrence has not yet been published, and could come from other chemical compounds.&#xA;I usually cross my fingers when I think about it.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/nature08228&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Lefèvre, F. Forget, F.&lt;/strong&gt; &amp;quot;Observed variations of methane on Mars unexplained by known atmospheric chemistry and physics.&amp;quot;&lt;strong&gt;Nature&lt;/strong&gt; (2009)&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-10-13T09:09:07.017" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="15273" PostTypeId="1" CreationDate="2018-10-08T18:44:38.060" Score="0" ViewCount="685" Body="&lt;p&gt;By air moving from high pressure area to low pressure area means that it's moving from colder area to a warmer area,  are they both not contradictory? I might have understood something in a wrong way, pls help. &lt;/p&gt;&#xA;" OwnerUserId="13714" LastActivityDate="2018-10-08T19:11:05.070" Title="When it is said that air moves from warm object to a cold object, how is it possible that air moves from high pressure area to low pressure area?" Tags="|temperature|barometric-pressure|air-currents|air|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15274" PostTypeId="2" ParentId="15273" CreationDate="2018-10-08T19:00:30.477" Score="4" Body="&lt;p&gt;You are correct that air generally moves along the surface from high pressure towards low pressure (not directly, but deflected due to the coriolis effect).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this does not imply that it is moving from a colder area to a warmer area. And, there is nothing contradictory in a cool air mass moving horizontally to displace a warm air mass.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Extratropical_cyclone&quot; rel=&quot;nofollow noreferrer&quot;&gt;Extratropical cyclones&lt;/a&gt;&lt;/em&gt; (a kind of low pressure system found in mid latitudes) are actually related to the movement of a cold front &lt;em&gt;and&lt;/em&gt; a warm front, as part of a frontal wave. They drive cold &lt;em&gt;and&lt;/em&gt; warm air masses to move.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your claim that &quot;air moves from warm object to a cold object&quot; might be the root of your misunderstanding. That claim isn't true. It &lt;em&gt;is&lt;/em&gt; true that &lt;em&gt;heat&lt;/em&gt; will move from a warmer object to a cooler object through conduction and radiation. But that is not related to whether the air itself will move. A local effect called a &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Sea_breeze&quot; rel=&quot;nofollow noreferrer&quot;&gt;sea breeze&lt;/a&gt;&quot; demonstrates the opposite scenario. A hot beach creates a warm, rising column of air (and a local area of low pressure), bringing in cooler air from the ocean to replace it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You have conflated the transfer of &lt;em&gt;heat&lt;/em&gt; with the movement of &lt;em&gt;air&lt;/em&gt; and &lt;em&gt;air masses&lt;/em&gt;.&lt;/p&gt;&#xA;" OwnerUserId="13988" LastEditorUserId="13988" LastEditDate="2018-10-08T19:11:05.070" LastActivityDate="2018-10-08T19:11:05.070" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15280" PostTypeId="2" ParentId="15214" CreationDate="2018-10-09T02:08:54.743" Score="8" Body="&lt;p&gt;I'm assuming this question is asking about the sea ice in the Arctic Ocean as opposed to ice caps such as that over Greenland. The sea ice on the Arctic Ocean is predominantly (overwhelmingly!) frozen ocean water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Arctic Ocean loses 17 to 18 thousand cubic kilometers of ice every summer, only to regain most of that melted ice during the long Arctic winter when the ocean freezes at the surface. That corresponds to a layer of ice well over a meter thick that melts and reforms every year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Arctic is a desert, and an extreme desert during the Arctic winter. At 40 below zero (Fahrenheit or Celsius), it's simply too cold to snow. The amount of precipitation that falls on the Arctic Basin over the six to seven months or so when the ocean freezes is about a tenth of a meter.  Snowfall cannot account for anywhere close to the meter+ thick layer of ice that forms during the Arctic winter. The tiny amount of snow that falls during the Arctic winter can't accumulate the way it does over ice caps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Compare with Antarctica. Antarctica, like the Arctic, is a desert. Unlike the Arctic, Antarctica is a continent. The little snow that does fall accumulates over the millennia, and longer. The Antarctic ice caps have existed for millions of years. Now look at the Arctic. There is very little Arctic sea ice that is over ten years old. (Thanks to global warming, there is very little Arctic sea ice that is over five years old nowadays.)&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-10-09T02:08:54.743" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15281" PostTypeId="1" AcceptedAnswerId="15284" CreationDate="2018-10-09T06:59:48.073" Score="1" ViewCount="225" Body="&lt;p&gt;Assuming that the oil reserves would end at a certain date, would it be expected that the kerosene be no longer used as fuel on a previous date due to the quality fall of barrels?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If so, would that date be much more previous in absolute or relative terms?&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorUserId="725" LastEditDate="2018-10-13T08:29:55.087" LastActivityDate="2018-10-13T08:29:55.087" Title="Will kerosene reserves deplete long before oil?" Tags="|petroleum|resources|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15282" PostTypeId="1" CreationDate="2018-10-09T07:06:08.843" Score="1" ViewCount="14" Body="&lt;p&gt;I was wondering if there is a tool that shows electric charge in the clouds.&#xA;Something like &lt;a href=&quot;https://www.ventusky.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;, but more detailed.&lt;/p&gt;&#xA;" OwnerUserId="14004" LastActivityDate="2018-10-09T07:06:08.843" Title="Is there a real time tool to monitor electric flow in the clouds?" Tags="|clouds|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15283" PostTypeId="2" ParentId="15281" CreationDate="2018-10-09T08:13:35.030" Score="1" Body="&lt;p&gt;There may be a language issue with this question or you are asking about something in a confusing way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By asking about kerosene &quot;wearing out&quot; do you mean wearing out like erosion &amp;amp; becoming thinner - which only happens to solid items not liquids.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or, are you asking about will kerosene be fully depleted before oil is fully depleted - fully depleted meaning, no longer existing?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you mean the latter, &lt;a href=&quot;https://en.wikipedia.org/wiki/Kerosene&quot; rel=&quot;nofollow noreferrer&quot;&gt;kerosene&lt;/a&gt; is not separate from oil. Kerosene is made from crude oil. &lt;a href=&quot;https://en.wikipedia.org/wiki/Oil_refinery&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oil refineries&lt;/a&gt; take crude oil &amp;amp; separate out the separate fractions of crude oil kerosene, petrol/gasoline, diesel fuel, heating oil and asphalt are all created by oil refiners from crude oil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When there is no more crude oil, or no oil refineries, there will be no more kerosene.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-10-09T08:13:35.030" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15284" PostTypeId="2" ParentId="15281" CreationDate="2018-10-09T09:29:14.593" Score="5" Body="&lt;p&gt;No.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the moment, we use &lt;a href=&quot;https://en.wikipedia.org/wiki/Cracking_(chemistry)&quot; rel=&quot;nofollow noreferrer&quot;&gt;cracking&lt;/a&gt; to turn heavy, long-chain hydrocarbons into more valuable short-chain hydrocarbons, such as petrol/gasoline and kerosene; as a general rule, lighter hydrocarbons are more valuable, at least up to butane.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Generally, it might take the form:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;C&lt;span class=&quot;math-container&quot;&gt;$_{16}$&lt;/span&gt;H&lt;span class=&quot;math-container&quot;&gt;$_{34}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\ce{-&amp;gt;}$&lt;/span&gt; 2 C&lt;span class=&quot;math-container&quot;&gt;$_8$&lt;/span&gt;H&lt;span class=&quot;math-container&quot;&gt;$_{18}$&lt;/span&gt;  (Octane, a typical petrol component)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that this is not balanced; to crack to fully-saturated products we need to add hydrogen, usually made from natural gas and water. This is why you sometimes see that a refinery will take 1 tonne of heavy crude and make 1.1 tonnes of petroleum products. This is called 'refinery gain'. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Essentially, as long as we have hydrocarbon feedstocks, we can make kerosene.&lt;/p&gt;&#xA;" OwnerUserId="8217" LastEditorUserId="6298" LastEditDate="2018-10-10T00:34:34.817" LastActivityDate="2018-10-10T00:34:34.817" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15286" PostTypeId="2" ParentId="15128" CreationDate="2018-10-09T18:01:08.500" Score="2" Body="&lt;p&gt;Yes it is used and it works. I've heard varying viewpoints on it's accuracy and dependability though. I remember my earth science lecturers were in three camps with it:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;one felt that the dates weren't consistently reliable, the data he'd gotten from astro-dating in the past had very poor independent confidence margins when there was no radiometric calibration. He implied that the results felt as though they had been pulled out of thin air.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;two would gather testable material for future study but didn't use astro-dating themselves. It was an interesting but immature technique that might be useful in future but not to them.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;only one felt that it was really, immediately useful.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Do note that this is in New Zealand, we're a geologically young and active country, so much so that we rarely need longer range radiometric testing like Uranium-Lead or even Potassium-Argon, we can Carbon date most of the sites we're interested in. Fine calibration of longer range datings is much less of an issue here than in older, more settled, locations.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-10-09T18:01:08.500" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15289" PostTypeId="1" CreationDate="2018-10-09T20:12:48.647" Score="9" ViewCount="243" Body="&lt;p&gt;Yesterday I read a number of news stories about the new IPCC's (International Panel on Climate Change) report regarding the current state of global warming. It reported that we are on track for hitting their safety threshold for global warming, namely an increase of 1.5 °C average temperatures since pre-industrial times. A number of reports are made, such as for example:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Maintaining the goal of 1.5 degrees instead of 2 degrees will result in 10cm lower sea levels by the year 2100.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;However it's the report on the effect on coral reefs that really shocked me. At the moment our level is 1 degree above pre-industrial levels. The report predicts that if the level is allowed to rise to 1.5 degrees (which is supposedly going to happen in 2030 at this rate), that 70 to 90 per cent of coral reefs will be destroyed. Further, if this metric rises to 2 degrees, that we can expect over 99% of coral reefs to be destroyed. This pretty much sounds to me that they will all but be destroyed if we allow up to a 2 degree increase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm pretty naive on the subject, so I'm wondering why such a temperature increase of half a degree can have such a marked effect on coral reefs in particular. &lt;/p&gt;&#xA;" OwnerUserId="13979" LastEditorUserId="725" LastEditDate="2018-10-13T08:42:41.013" LastActivityDate="2021-08-14T14:07:36.290" Title="How can half a degree of average temperature result in such devastating impact on coral reefs?" Tags="|climate-change|ecology|geobiology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15293" PostTypeId="1" AcceptedAnswerId="15298" CreationDate="2018-10-10T11:21:16.807" Score="1" ViewCount="303" Body="&lt;p&gt;What is this stone from the alps of provence?&#xA;It's two spheres, one of them is made of at least 25 layers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/bm74b.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lsnYg.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Y1wRy.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2018-10-10T11:26:43.290" LastActivityDate="2018-10-11T18:40:26.460" Title="What is this stratefied limestone sphere?" Tags="|minerals|fossils|chalk|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15294" PostTypeId="1" CreationDate="2018-10-10T11:29:06.313" Score="5" ViewCount="120" Body="&lt;p&gt;I was reading about tropical cyclones and tropical waves and there I saw a study mentioning its relationship with MJO activities. I saw several research papers which discuss about MJO waves. They only mention that a rising sinking pattern travels eastward at a given speed every 40-60 days. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I could not find any detailed mechanism about how these waves are generated near Africa and Western Indian Ocean. How is the wet-dry pattern formed? Does it have any relation with the high radiation in Northern hemisphere summers? If there is any, do these waves emerge during Southern hemisphere summers too?&lt;/p&gt;&#xA;" OwnerUserId="11162" LastEditorUserId="11162" LastEditDate="2018-10-10T11:42:12.827" LastActivityDate="2018-10-10T11:42:12.827" Title="How do the Madden Julian Oscillation (MJO) waves originate?" Tags="|meteorology|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15295" PostTypeId="1" AcceptedAnswerId="15299" CreationDate="2018-10-10T12:16:55.800" Score="2" ViewCount="183" Body="&lt;p&gt;Is there something wrong with this image?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found it in Wikipedia's article &lt;a href=&quot;https://en.wikipedia.org/wiki/Ecliptic_coordinate_system&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ecliptic coordinate system&lt;/a&gt; and the image's source page is &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Ecliptic_grid_globe.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What bothers me is the orientation of the Earth's surface (continents). &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The horizontal plane with the red line around the sphere represents the plane of the ecliptic. The ecliptic is basically &lt;em&gt;the plane of Earth's orbit around the Sun&lt;/em&gt;, in as much as that can be considered to be a plane. (caveats, details, mumble, mumble J2000.0 mumble...)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The inclined plane with the blue line is the Celestial Equator, which basically coincides with the Equator of the Earth (...mumble...).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;If I understand correctly then, the North pole of the Earth should point in a direction that is perpendicular to the Earth's equator and celestial equator, but it looks to me like this is drawn with the north pole pointing directly up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Am I wrong, or confused, or both?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Tkz3k.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Tkz3k.png&quot; alt=&quot;Ecliptic coordinate system?&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2019-06-23T15:38:40.370" Title="Is the representation of Earth oriented correctly in this image?" Tags="|geography|equator|coordinate-system|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15298" PostTypeId="2" ParentId="15293" CreationDate="2018-10-10T16:51:39.983" Score="1" Body="&lt;p&gt;Your fossils look like Stromatolites to me.  Stromatolites start as a film of cyanobacteria on the substrate in marine and sometimes freshwater environments.  I am not sure if the bacteria capture sediment or weather the carbonates form on the bacteria themselves but overtime they develop layers of carbonate and other mineral deposits which later became fossilized.  There is a wealth of information about these on the internet.  Stromatolites are still found today, &lt;a href=&quot;https://www.australiascoralcoast.com/destination/stromatolites-hamelin-pool&quot; rel=&quot;nofollow noreferrer&quot;&gt;Living Stromatolites&lt;/a&gt;.  Wikipedia has a good description of stromatolites &lt;a href=&quot;https://en.wikipedia.org/wiki/Stromatolite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stromatolites on Wikipedia&lt;/a&gt;.  &lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2018-10-10T16:51:39.983" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15299" PostTypeId="2" ParentId="15295" CreationDate="2018-10-10T17:10:07.393" Score="5" Body="&lt;p&gt;The way &quot;I see the diagram&quot; it looks weird, but it is probably correct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My perception is that it is about frames of reference. We are used to seeing the Earth with Earth's north at the top, not at 23.5 deg from the vertical.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This picture has the ecliptic pole at the top. As you state, Earth's equator matches the celestial equator. The Earth's poles would be at right angles to it and the north pole would be in the middle of the white mass at the top of the Earth - representing the Arctic ice sheet&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you imagine a line from this point, perpendicular with the celestial equator it matches zero degrees latitude and is sort of sub parallel with the west coast of Africa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other thing that might be confusing our perception is the representation of the land masses is not accurate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looking at the representation for Europe, Italy is not present, neither is the Balkan Peninsular or the islands of Britain &amp;amp; Ireland. Scandinavia just looks wrong! Iceland is present and the Arctic ice extends too far southwards. The last time I looked there wasn't an ice sheet between Iceland &amp;amp; Greenland. Also, the Red Sea isn't represented.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-10-10T17:10:07.393" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15300" PostTypeId="2" ParentId="15249" CreationDate="2018-10-10T17:31:03.050" Score="2" Body="&lt;p&gt;Quite an interesting stone.  I cannot identify all of it but given its location, and the patterns it is primarily Agate, a type of crypto-crystalline quartz.  The fourth picture down shows a layer of lace agate across the top of the stone at that location, it is underlain with a more massive translucent agate.  In the Oregon area there are many areas with volcanic rock.  The silicas have dissolved from the volcanic material in the past and this silca has been slowly deposited to form the rock you found.  The following links give you an idea of the types of agate you can find.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.geologyin.com/2016/08/types-of-agate-with-photos.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Types of agate&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.quartzpage.de/agate.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;A more detailed description of types and formation&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would warn you that there are a number of names for the various types of agates and the naming doesn't seem to follow any convention.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2018-10-10T17:31:03.050" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15301" PostTypeId="1" AcceptedAnswerId="15305" CreationDate="2018-10-10T19:25:03.397" Score="3" ViewCount="69" Body="&lt;p&gt;What is the purpose for doing this? Is it inaccurate to calculate anomalies for variables such as sea surface temperature and precipitation based on a different time period?&lt;/p&gt;&#xA;" OwnerUserId="8219" LastActivityDate="2018-10-11T07:53:39.013" Title="Why are climate anomalies calculated relative to 1981-2010 average?" Tags="|climate|oceanography|precipitation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15302" PostTypeId="1" CreationDate="2018-10-11T03:39:55.803" Score="4" ViewCount="106" Body="&lt;p&gt;Indonesia had multiple major earthquakes this year&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/2018_Lombok_earthquake&quot; rel=&quot;noreferrer&quot;&gt;A series of earthquakes&lt;/a&gt; in Lombok between July and August, including a 7.0 mainshock&lt;/li&gt;&#xA;&lt;li&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/2018_Sulawesi_earthquake_and_tsunami&quot; rel=&quot;noreferrer&quot;&gt;7.5 earthquake + tsunami&lt;/a&gt; in Sulawesi, September 2018&lt;/li&gt;&#xA;&lt;li&gt;A &lt;a href=&quot;https://www.straitstimes.com/asia/se-asia/shallow-60-magnitude-quake-hits-off-indonesias-java-usgs&quot; rel=&quot;noreferrer&quot;&gt;6.0 earthquake&lt;/a&gt; near Java, on 11 October 2018&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I'm aware that Indonesia sits in an earthquake zone, but historically I don't think so many big ones occur in such a close time. Also, this spread out in different islands (e.g. the epicentres in Java and Sulawesi are ~1,000 km apart) over several months, so it doesn't look (at least to me) like typical mainshock-aftershock relationship. Were they related in some way? e.g. Do they indicate an increase seismic activity in the region?&lt;/p&gt;&#xA;" OwnerUserId="14015" LastActivityDate="2019-12-06T15:09:57.160" Title="Are Indonesian 2018 earthquakes related?" Tags="|earthquakes|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15303" PostTypeId="2" ParentId="15266" CreationDate="2018-10-11T04:22:53.773" Score="1" Body="&lt;p&gt;Carboniferous CO&lt;sub&gt;2&lt;/sub&gt; levels may not have been unlike today's. Evidence for this is primarily from long term geochemical modeling work, as there are few direct proxies of sufficient age.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can easily cite one source, as it's from my own paper, but please check the reference list for the other datasets. &lt;a href=&quot;http://dx.doi.org/10.1016/j.chemgeo.2013.10.012&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://dx.doi.org/10.1016/j.chemgeo.2013.10.012&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/iYktM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iYktM.jpg&quot; alt=&quot;Phanerozoic CO2, fig. 5, p. 294&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12611" LastEditorUserId="725" LastEditDate="2018-10-13T08:39:13.480" LastActivityDate="2018-10-13T08:39:13.480" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15305" PostTypeId="2" ParentId="15301" CreationDate="2018-10-11T07:53:39.013" Score="2" Body="&lt;p&gt;In theory the choice of baseline average is irrelevant, because the purpose of using anomalies to to clearly see the change over time, allowing different absolute values to be compared.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although in climate studies, we try to use baselines that are as 'pre-industrial' as possible to try and get the change from 'natural'.&lt;/p&gt;&#xA;" OwnerUserId="8217" LastActivityDate="2018-10-11T07:53:39.013" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15306" PostTypeId="2" ParentId="9089" CreationDate="2018-10-11T12:16:55.693" Score="1" Body="&lt;p&gt;It's not so much the amount of &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; released but the rate at which it would be released that contributes to the Greenhouse effect. Burning will release CO2 faster than any form of natural decomposition&lt;/p&gt;&#xA;" OwnerUserId="14018" LastEditorUserId="2470" LastEditDate="2020-01-04T19:29:49.613" LastActivityDate="2020-01-04T19:29:49.613" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15309" PostTypeId="1" CreationDate="2018-10-11T17:29:07.797" Score="1" ViewCount="66" Body="&lt;p&gt;I found this odd shaped rock along a rocky river bed (dry) near the Illinois river in Cave Junction,  Oregon.  It is shaped like a Club and is super heavy.  It has a distinguishable ring around the base uniform in size,  and makes a dense ringing sound when rubbed?  I see some reflective flakes when turned and grainy but solid material on surface, 18 inches length. any ideas? &lt;a href=&quot;https://i.stack.imgur.com/Yfqyp.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Yfqyp.jpg&quot; alt=&quot;rock image&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/dfak4.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dfak4.jpg&quot; alt=&quot;rock length reference 5 in ruler&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/ynJxh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ynJxh.jpg&quot; alt=&quot;close up of ring on base&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14020" LastActivityDate="2018-10-11T21:12:10.170" Title="What is this rock found in the Illinois Valley of Southern Oregon?" Tags="|geology|" AnswerCount="1" CommentCount="1" ClosedDate="2019-08-30T17:52:52.253" ContentLicense="CC BY-SA 4.0" />
  <row Id="15310" PostTypeId="2" ParentId="15293" CreationDate="2018-10-11T18:40:26.460" Score="1" Body="&lt;p&gt;It looks like a dripstone (stalactite). This also explains the milk white color... Stromatolites show a more distinct layering caused by lamination layers of algae and captured particles. &lt;/p&gt;&#xA;" OwnerUserId="13398" LastActivityDate="2018-10-11T18:40:26.460" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15311" PostTypeId="2" ParentId="15309" CreationDate="2018-10-11T21:12:10.170" Score="1" Body="&lt;p&gt;This is a sandspike concretion&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://tywkiwdbi.blogspot.com/2013/01/unexplained-sand-spike-concretions.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pictures can be seen here&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sometimes, only a spike is found and sometimes the spike has some 'balls' or round concretions attached to it. &lt;/p&gt;&#xA;" OwnerUserId="13398" LastActivityDate="2018-10-11T21:12:10.170" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15313" PostTypeId="1" CreationDate="2018-10-12T03:44:56.683" Score="2" ViewCount="81" Body="&lt;p&gt;At 18:03 PDT at La Jolla Cove the lifeguard's bulletin board stated predicted low tide at 5:36 (17:36 PDT?). In fact, it was already after 6:00 and the sun had not yet set. The moon was a waxing crescent, about 2 days old. I infer that the moon would be setting in about 2 hours so the tide should be low in about 3 hours, that is, around 21:00 PDT. How can the discrepancy be explained?&lt;/p&gt;&#xA;" OwnerUserId="14024" LastActivityDate="2018-10-12T10:51:32.747" Title="predicting low tide" Tags="|oceanography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15317" PostTypeId="1" AcceptedAnswerId="15319" CreationDate="2018-10-12T08:57:22.663" Score="3" ViewCount="76" Body="&lt;p&gt;now its well known that common names are used to name weather storms but on what bases are they named ? is it the person who first notices them ? Is it the the most common name in the region where the cyclone/typhoons/hurricanes develop ?or something else entirely ?  &lt;/p&gt;&#xA;" OwnerUserId="14026" LastActivityDate="2018-10-12T11:30:32.927" Title="On what basis are hurricanes,cyclones or typhoons named?" Tags="|meteorology|climate|weather-forecasting|" AnswerCount="1" CommentCount="1" ClosedDate="2018-10-15T03:56:12.017" ContentLicense="CC BY-SA 4.0" />
  <row Id="15318" PostTypeId="2" ParentId="15313" CreationDate="2018-10-12T10:51:32.747" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;I infer that the moon would be setting in about 2 hours so the tide should be low in about 3 hours, that is, around 21:00 PDT. How can the discrepancy be explained?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Your inference is based on multiple misconceptions. The key misconception is that the tides at La Jolla are solely due to the Moon's position in the sky. A secondary misconception is that the time of moonset is a key indicator with regard to the tides at La Jolla.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regard to the latter, we're often told that the Moon rises and sets 50 minutes later than it did the day before. While this is the average behavior, it is rarely the actual behavior&lt;sup&gt;1&lt;/sup&gt;. The time between subsequent moonrises/moonsets can vary quite a bit from this mean, with the variation depending on the phase of the Moon, the time of the year, the latitude of the observer, and other influences. For La Jolla, the times between subsequent moonrises/moonsets just for October 2018 varies from 36 minutes to 68 minutes later than on the previous day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regard to the former, the tides at La Jolla result from several cyclical influences, plus non-cyclical variations caused by things such as weather. The key cyclical influences, from &lt;a href=&quot;https://tidesandcurrents.noaa.gov/harcon.html?id=9410230&quot; rel=&quot;noreferrer&quot;&gt;Harmonic Constituents - NOAA Tides and Currents&lt;/a&gt; for La Jolla are&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Name   Amplitude (ft)  Phase(°)  Speed (°/hr)&#xA; M2      1.64           270.1     28.984104&#xA; K1      1.089           86.6     15.041069&#xA; O1      0.699           80.2     13.943035&#xA; S2      0.669          258.5     30.0&#xA; N2      0.384          254.1     28.43973&#xA; P1      0.344           83.4     14.958931&#xA; SA      0.259          175.3      0.0410686&#xA; Q1      0.125           77.2     13.398661&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The above shows that the M2 tidal constituent is dominant at La Jolla, but it also shows that it is not overwhelmingly so. The predicted tides result from the composition of these constituents, plus a bunch of smaller constituents that I did not list. The predicted tide levels for La Jolla CA for October 2018 is shown below. Note the complex pattern of beats in the graph.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/o7VAg.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/o7VAg.jpg&quot; alt=&quot;Graph of tide predictions for La Jolla CA for October 2018.&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;Source: &lt;a href=&quot;https://tidesandcurrents.noaa.gov/noaatidepredictions.html?id=9410230&quot; rel=&quot;noreferrer&quot;&gt;https://tidesandcurrents.noaa.gov/noaatidepredictions.html?id=9410230&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;&lt;sup&gt;1&lt;/sup&gt;Three statisticians went duck hunting. Two shot at a duck. Both missed, one ten feet to the left, the other ten to the right. The third proclaimed &quot;We hit, on average!&quot;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-10-12T10:51:32.747" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15319" PostTypeId="2" ParentId="15317" CreationDate="2018-10-12T11:25:16.577" Score="2" Body="&lt;p&gt;The names are set well in advance. For example, the first four north Atlantic hurricanes in 2022 will be named Alex, Bonnie, Colin, and Danielle. In fact, the names of the north Atlantic hurricane in 2022 will be exactly the same as those in 2016, with one exception. Hurricane Matthew in 2016 was a catastrophic category 5 storm that claimed a number of lives and that resulted in large economic losses. The name Matthew has been retired because of this, so the 13th named north Atlantic storm in 2022 will be named Martin rather than Matthew.  The US recycles the names it uses on a six year basis, but the names of significant storms are retired and replaced with some new name.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Names for tropical cyclones elsewhere in the world follow a similar convention. Names are set well in advance, with the lists of names being recycled after some number of years. As was the case with Matthew, the names of catastrophic storms that result in a number of deaths and/or large economic impacts are retired from those lists.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2018-10-12T11:30:32.927" LastActivityDate="2018-10-12T11:30:32.927" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="15322" PostTypeId="1" AcceptedAnswerId="15325" CreationDate="2018-10-12T18:57:42.387" Score="11" ViewCount="2313" Body="&lt;p&gt;Hurricane Michael recently hit Florida as a Category 4 storm, and after the remnants passed across a great deal of the east coast of the United States it appears to have re-emerged into the Atlantic Ocean as a &quot;tropical storm&quot; with some models predicting it will &lt;a href=&quot;http://derecho.math.uwm.edu/models/archive/2018/al142018/al142018_2018101206.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;cross the Atlantic&lt;/a&gt; and a couple even suggesting it will then turn south and possibly loop back west again. Unfortunately the model I saw predicting the full turn has been overwritten by a new forecast, so I can't put a link here but it is intriguing as a possibility.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has any hurricane or other tropical storm ever managed to hit land deeply as Michael did, where most of the storm has been inland for more than a couple hundred miles, and then re-emerge over the same ocean and reform into a substantial storm in the same ocean?  If it struck two different land masses, did a whole loop across a basis hitting a second time close to the first area, or if regained most of or more than its former strength that would also be notable but not required.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_Atlantic%E2%80%93Pacific_crossover_hurricanes&quot; rel=&quot;nofollow noreferrer&quot;&gt;This page&lt;/a&gt; mentions hurricanes that have crossed from one ocean to another but does not mention storms that have reformed in the same Ocean (with the Caribbean counting as part of the Atlantic).  One reason I'm not wanting to count these storms is that to cross between oceans like this requires a relatively small jump over land, especially if done across Central America, such that a significant part of the storm may always be close enough to water to fuel it, whereas Michael seems to have traveled at least 800 miles across land without much ocean support and is still being reported by multiple weather sources as being &quot;tropical storm&quot; strength and projected to possibly be a tropical storm all the way across the Atlantic, for instance in this forecast: &#xA;&lt;a href=&quot;https://i.stack.imgur.com/EOcGq.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EOcGq.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(This copy is here because this image is from &lt;a href=&quot;http://weather.unisys.com/sites/default/files/mnt/webdata/hurricane/atlantic/2018/MICHAEL/track.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;this link&lt;/a&gt; and will likely be overwritten as soon as the next forecast is run.)&lt;/p&gt;&#xA;" OwnerUserId="14031" LastEditorUserId="6298" LastEditDate="2018-10-16T19:48:48.267" LastActivityDate="2018-10-16T19:48:48.267" Title="Has a hurricane or cyclone ever reformed after passing over a large land mass?" Tags="|meteorology|tropical-cyclone|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15325" PostTypeId="2" ParentId="15322" CreationDate="2018-10-12T21:35:58.390" Score="10" Body="&lt;p&gt;Since you don't seem interested in &lt;a href=&quot;http://www.aoml.noaa.gov/hrd/tcfaq/E15.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atlantic-Pacific crossovers&lt;/a&gt;, of which there are several good examples.....&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2004's &lt;a href=&quot;https://en.wikipedia.org/wiki/Hurricane_Ivan&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hurricane Ivan&lt;/a&gt; made landfall on the Gulf Coast, degraded into a tropical depression and was eventually declassified while crossing the southeast US. After coming back into the Atlantic, Ivan tracked back south, re-formed into a tropical depression, then hit the Atlantic coast of Louisiana.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/ETgRv.png&quot; alt=&quot;Ivan track. Source: NOAA via Wikipedia&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The key was the southward track in the Atlantic. Hurricanes weaken when they're that far north; they're away from the warm ocean waters that generated them in the first place.  But because Ivan tracked south into warmer waters it was able to strengthen a little. It may have been pushed by a cold front. But also, the next hurricane, &lt;a href=&quot;https://en.wikipedia.org/wiki/Hurricane_Jeanne&quot; rel=&quot;nofollow noreferrer&quot;&gt;Jeanne&lt;/a&gt;, was already approaching Florida, so Ivan may have been sucked into the circulation around it. Jeanne did its own loop-de loop out the in the Atlantic, so the jet stream may have affected both.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6298" LastEditDate="2018-10-16T17:09:19.943" LastActivityDate="2018-10-16T17:09:19.943" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15328" PostTypeId="2" ParentId="15289" CreationDate="2018-10-13T09:05:36.620" Score="7" Body="&lt;p&gt;Coral die because of &lt;a href=&quot;https://en.wikipedia.org/wiki/Coral_bleaching&quot; rel=&quot;noreferrer&quot;&gt;coral bleaching&lt;/a&gt;, a process in which the symbiotic algae living in the coral (which give the coral its colour), leave the coral host.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bleaching can occur for a variety of reasons, but the ones that relate to a warming climate are:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Ocean acidification caused by dissolution of carbon dioxide in the water.&lt;/li&gt;&#xA;&lt;li&gt;Thermal stress. According to this &lt;a href=&quot;https://www.mauireefs.org/why-do-corals-bleach/&quot; rel=&quot;noreferrer&quot;&gt;website&lt;/a&gt;, &quot;Corals do best when ocean water is between 73 degrees F and 84 degrees F.&quot; (22–29 °C). Long durations of heated sea surface water exceeding that would cause bleaching and coral death. For example, a &lt;a href=&quot;http://www.gbrmpa.gov.au/visit-the-reef/current-conditions-on-the-great-barrier-reef/latest-detailed-observed-forecast-and-environmental-conditions&quot; rel=&quot;noreferrer&quot;&gt;recent bleaching event in the Great Barrier Reef had temperatures&lt;/a&gt; of 4 °C above average, where the average is around 27 to 28. This puts it above the comfort zone of the coral.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-10-13T09:05:36.620" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15329" PostTypeId="2" ParentId="15221" CreationDate="2018-10-13T09:16:46.577" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;How likely is that the next big earthquake (and tsunami) will hit the Philippines again?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The likelihood is 100%, but we don't know when. It could be tomorrow, it could be in a year, or it could be in 100 years. Make sure you are prepared for such an event.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Philippines are situated above a subduction zone (the Philippine trench), so an earthquake is inevitable. However, it is impossible to predict exactly when and where it will happen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for tsunamis, these propagate from earthquake epicentres, so the Philippines are susceptible to tsunamis generated elsewhere in the area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You are drawing a line between the Bali and Palu events, and suggesting that the next  one will be along that line. This is not how it works. The earthquake could be on the line (by chance), or it could not. There is no way of predicting.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-10-13T09:16:46.577" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15330" PostTypeId="1" AcceptedAnswerId="15331" CreationDate="2018-10-13T19:20:29.613" Score="1" ViewCount="1310" Body="&lt;p&gt;What is this &lt;a href=&quot;https://www.google.co.uk/maps/place/33%C2%B002&amp;#39;02.8%22N+37%C2%B012&amp;#39;09.6%22E/@32.9948571,37.0567835,58105m/data=!3m1!1e3!4m6!3m5!1s0x0:0x0!7e2!8m2!3d33.0341008!4d37.2026555&quot; rel=&quot;nofollow noreferrer&quot;&gt;big black dot&lt;/a&gt; on the satellite view of google maps, located in Syria at about 4:00 from Damascus?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VIWOr.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VIWOr.png&quot; alt=&quot;Big Black dot in Syria&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14037" LastActivityDate="2018-10-13T20:19:42.110" Title="What is this big Black Mass in Syria, as seen on google maps?" Tags="|volcanology|desert|" AnswerCount="1" CommentCount="1" ClosedDate="2018-10-14T15:56:48.860" ContentLicense="CC BY-SA 4.0" />
  <row Id="15331" PostTypeId="2" ParentId="15330" CreationDate="2018-10-13T20:19:42.110" Score="4" Body="&lt;p&gt;This is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Al-Safa_(Syria)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Al-Safa&lt;/a&gt; Volcano in Syria. According to Wikipedia it last erupted in 1850 AD.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2018-10-13T20:19:42.110" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15332" PostTypeId="1" CreationDate="2018-10-14T00:37:55.620" Score="1" ViewCount="651" Body="&lt;p&gt;If this is due to the Coriolis Effect, my other question would be how does the wind go upwards to form the storm clouds?&lt;/p&gt;&#xA;" OwnerUserId="14040" LastActivityDate="2019-02-17T00:54:17.037" Title="If storms form above low pressure regions, why doesn't the eye of a hurricane, a low pressure region, have any storms?" Tags="|meteorology|wind|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15335" PostTypeId="2" ParentId="15332" CreationDate="2018-10-14T20:17:08.987" Score="4" Body="&lt;p&gt;While hurricanes are low pressure systems, their structure, determined by the Coriolis Effect as you mentioned, is determined by winds getting deflected slightly from rushing directly into the center of the storm.  This deflection causes the characteristic rotation of large scale low pressure systems, including hurricanes.  When a hurricane forms and &lt;em&gt;surface&lt;/em&gt; low pressure deepens, a balancing anticyclonic high pressure system actualy forms in the upper troposphere, &lt;em&gt;above&lt;/em&gt; the budding storm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Air at this altitude actually spirals out and away from the center of the cyclone, pulling more air below in toward the eye (causing a positive feedback loop).  However, some of this high pressure, high altitude air &quot;leaks&quot; inward towards the center of the storm instead of outward, and pressure eventually increases enough that it counteracts the strength of any updrafts in the center/eyewall of the storm. This air begins to descend (&lt;em&gt;subsidence&lt;/em&gt;) in the center of the eye, stifling any convection and causing clearing at the mid and lower levels - creating the famous stadium effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The convection/rising motion in the storm is caused by air converging as it &lt;em&gt;approaches&lt;/em&gt; the center of the hurricane.  Essentially, when there is a bunch of air rushing toward the center of low pressure, it has nowhere to go when it arrives but up, thus forming updrafts!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Vwyq7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Vwyq7.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13142" LastEditorUserId="13142" LastEditDate="2019-02-17T00:54:17.037" LastActivityDate="2019-02-17T00:54:17.037" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15336" PostTypeId="1" CreationDate="2018-10-14T20:59:56.183" Score="1" ViewCount="48" Body="&lt;p&gt;There is good evidence that the presence of water on a planet's surface is necessary for that planet to have plate tectonics. My question is this: Do we know if there is a minimum amount of surface water that is needed to sustain this? How little water could a planet hypothetically have, yet still possess active plate tectonics?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks in advance!&lt;/p&gt;&#xA;" OwnerUserId="14045" LastActivityDate="2018-10-14T20:59:56.183" Title="Minimum Surface Water for Plate Tectonics?" Tags="|plate-tectonics|planetary-science|hydrogeology|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15338" PostTypeId="2" ParentId="12685" CreationDate="2018-10-14T22:18:49.627" Score="-2" Body="&lt;p&gt;Well... The atmosphere is very sensitive to minute changes... The density and aromatic pressure shift if when a butterfly flaps its wings... Ok just saying there is an effect... But the easiest way to measure the difference would be to ask the question... Wood human heat keep us warm if tge sun went out... And that answer is obvious... So no, climate change isnt effected much by human heat... &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Besides heat.we are also machines that turn o2 into c02... So that can also be taken into consideration regarding hownare bodies affect climate change... Though again this measure almost nil... &lt;/p&gt;&#xA;" OwnerUserId="14047" LastActivityDate="2018-10-14T22:18:49.627" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15340" PostTypeId="1" AcceptedAnswerId="15342" CreationDate="2018-10-15T02:28:22.283" Score="10" ViewCount="1877" Body="&lt;p&gt;I am wondering why, since the oceans could feasibly hold all of the dry land, they in fact do not.  For example, the Mariana Trench drops to -10.9km, while Mount Everest only reaches to +8.8km.  Further, the oceans cover 71% of the surface.  This causes me to suspect that the negative elevation parts of the Earth could easily hold the positive.  Due to erosion, will the oceans eventually consume the mountains?  What is the timescale involved with such a process, and what forces counteract it?&lt;/p&gt;&#xA;" OwnerUserId="14049" LastActivityDate="2018-10-16T17:36:54.433" Title="Will the oceans swallow all of the land?" Tags="|plate-tectonics|water|erosion|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15341" PostTypeId="1" CreationDate="2018-10-15T02:49:48.930" Score="4" ViewCount="122" Body="&lt;p&gt;I was wondering, if we measured the carbon isotopic ratio of methane on Mars and found that it was very negative (i.e. it contained more carbon-12 than carbon-13), would this provide definitive proof that life exists on Mars.&lt;/p&gt;&#xA;" OwnerUserId="13647" LastActivityDate="2018-10-15T02:49:48.930" Title="Carbon Isotopic Ratio of Methane on Mars" Tags="|mars|methane|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15342" PostTypeId="2" ParentId="15340" CreationDate="2018-10-15T03:29:18.760" Score="11" Body="&lt;p&gt;If no new mountains were built, yes. Ultimately the processes of erosion would render the continents flat, and the seas would be left shallow and filled with sediments. The reason that this doesn't occur is that tectonic processes cause 'orogenesis', the formation of new mountains. The subduction of oceanic crust at plate margins is also responsible for trenches such as the Mariana, and ultimately recycles sediments into the mantle; thereby preventing the ocean floor from filling up.&lt;/p&gt;&#xA;" OwnerUserId="14045" LastActivityDate="2018-10-15T03:29:18.760" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15343" PostTypeId="1" AcceptedAnswerId="15345" CreationDate="2018-10-12T19:04:47.190" Score="12" ViewCount="4384" Body="&lt;p&gt;Is there lower gravity at the Hudson Bay? How does this happen? And where exactly is this because I might want to go. &lt;/p&gt;&#xA;" OwnerDisplayName="Flavor" LastActivityDate="2019-09-05T20:51:16.063" Title="Hudson Bay Has Low Gravity?" Tags="|gravity|" AnswerCount="4" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15344" PostTypeId="2" ParentId="15343" CreationDate="2018-10-12T19:41:10.323" Score="11" Body="&lt;p&gt;&lt;a href=&quot;https://www.theschoolrun.com/homework-help/gravity&quot; rel=&quot;noreferrer&quot;&gt;The link&lt;/a&gt; you give seems largely plausible about the cause of the anomaly in that area:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;a 2007 study found that now-melted glaciers were to blame. The ice that once covered the area during the last ice age has long since melted, but the Earth hasn't entirely snapped back from the burden. Since gravity over an area is proportional to the mass on top of that region, and the glacier's imprint pushed aside some of the Earth's mass, gravity is a bit less strong in the ice sheet's imprint. The slight deformation of the crust explains the unusually low gravity in the area.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However it is massively wrong about the scale of it. &lt;a href=&quot;https://academo.org/demos/gravity-map/&quot; rel=&quot;noreferrer&quot;&gt;This site&lt;/a&gt; does indeed show a negative anomaly in that area, about 50 milliGals, or 0.05 &lt;span class=&quot;math-container&quot;&gt;$cm/s^2$&lt;/span&gt; or about 50 parts per million of the Earths gravitational field.I wonder if someone confused 50 ppm with 50%?&lt;/p&gt;&#xA;" OwnerUserId="14051" OwnerDisplayName="Steve Linton" LastActivityDate="2018-10-12T20:04:31.390" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15345" PostTypeId="2" ParentId="15343" CreationDate="2018-10-12T19:44:27.657" Score="15" Body="&lt;p&gt;Gravitational acceleration does vary.  It tends to be strongest at the poles and weakest at the equator, this is due to the oblate shape of the Earth which means that at the Equator you are further from the centre, and gravity decreases the further you are.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also the spinning of the Earth makes gravity seem less at the Equator.  The combination of these effects causes felt gravity to vary from about 9.77 &lt;span class=&quot;math-container&quot;&gt;$\frac{N}{kg}$&lt;/span&gt; at the Equator to 9.83 &lt;span class=&quot;math-container&quot;&gt;$\frac{N}{kg}$&lt;/span&gt; as you travel from the equator to the pole (a difference of about 0.6% in weight).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On top of this there are local variations in gravity, which are called gravitational anomalies. They are caused by the structure of the rocks in a particular location.  There is a large scale anomaly over the Hudson Bay region, and so gravity there is slightly weaker than you would expect at its latitude. Gravitation anomalies are generally due some &lt;a href=&quot;https://science.howstuffworks.com/environmental/earth/geophysics/missing-gravity.htm&quot; rel=&quot;noreferrer&quot;&gt;combination of two mechanisms&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The massive ice sheet that covered Canada during the Ice Age pushed mass down and south. Now that the ice has gone, the rocks are rebounding back but the mass has still been pushed aside. Less mass means less gravity.&lt;/li&gt;&#xA;&lt;li&gt;There are mantle plumes - hot spots like Yellowstone and cold spots where the mantle sinks.  Hot spots tend to have high gravity and cold ones tend to have lower gravity.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;These two effects combine in the Hudson Bay region to give a distinct gravitational anomaly.  However the difference is tiny. There is still lower gravity in Florida than in Hudson, simply because Florida is closer to the Equator (and thus further from the Earth's center). And you still wouldn't notice the difference between the strongest gravity and the weakest. It is much too small to feel (though pole vaulters still could have a small gain [1 or 2 cm] if they compete in countries close to the Equator). &lt;strong&gt;It is absolutely not the case that there is any part of Caanda where you can float or experience &quot;half the strength of gravity&quot;.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="9563" OwnerDisplayName="James K" LastEditorUserId="9563" LastEditDate="2018-10-15T16:20:08.380" LastActivityDate="2018-10-15T16:20:08.380" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15346" PostTypeId="2" ParentId="15343" CreationDate="2018-10-12T19:47:41.657" Score="9" Body="&lt;p&gt;The anomaly at Hudson's Bay is actually about &lt;a href=&quot;http://www.sciencephoto.com/media/159675/view&quot; rel=&quot;nofollow noreferrer&quot;&gt;0.005%&lt;/a&gt; - or 1/200th of a percent. That tiny difference is likely caused by both the additional convection of molten rock underneath the area and the &quot;crushing&quot; of land due to the higher weight of a glacier presence in the depression back in the last ice age - the latter a temporary issue from which it has yet to rebound, but will in ~5000 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MhR3K.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MhR3K.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Credit: Mark Simons / California Institute of Technology, 1997 / Science Photo Library&lt;/p&gt;&#xA;" OwnerDisplayName="Kyle" LastEditorUserId="6031" LastEditDate="2019-04-22T04:10:19.683" LastActivityDate="2019-04-22T04:10:19.683" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15347" PostTypeId="1" CreationDate="2018-10-15T12:39:48.987" Score="6" ViewCount="381" Body="&lt;p&gt;What is the probability that the weather tomorrow will be equal to the weather today (e.g. more specifically, if we know there had been more than 1mm precipitation during one day, what is the conditional probability that there will be more than 1mm precipitation also the next day)?&#xA;Can you guide me to some references?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to use this example in a lecture to illustrate to physics students the concept of probability in forecasting.&lt;/p&gt;&#xA;" OwnerUserId="14052" LastEditorUserId="2470" LastEditDate="2018-10-15T23:41:37.577" LastActivityDate="2018-10-15T23:41:37.577" Title="Probability ( weather tomorrow = weather today)?" Tags="|statistics|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="15348" PostTypeId="2" ParentId="15347" CreationDate="2018-10-15T15:22:46.550" Score="5" Body="&lt;p&gt;As mentioned, the term you are looking for is persistence.  Generally its strength varies wildly depending on what variable you are looking at, the location, and by whether you also further select other factors like season and other meteorological variables.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would expect daily precipitation persistence is a relatively bad predictor, given that precipitation is often either a short-term event driven by very transient dynamics like frontal passage, or sees a fairly random spatial distribution over small areas driven by small perturbations and nonlinear interactions (thus typically leading to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4511/how-to-interpret-hourly-precipitation-forecast&quot;&gt;rain PoPs&lt;/a&gt; regularly being more useful than binary forecasts).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Persistence is often used as a basis to compute forecast skill... but it seems to be be reported in research using more sophisticated summarization metrics like skill scores than straight probabilities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, with a little searching I did at least find &lt;a href=&quot;ftp://ftp.library.noaa.gov/docs.lib/htdocs/rescue/mwr/091/mwr-091-06-0298.pdf&quot; rel=&quot;noreferrer&quot;&gt;A Markov Chain Model for the Probability of Precipitation Occurrence in Intervals of Various Length&lt;/a&gt; by James E. Caskey, Jr., which did at least have a table along the lines you've asked... for Denver, Colorado between 1949-1958, using 0.01&quot; (0.254 mm) as the condition:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/T7TkC.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/T7TkC.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For those struggling to figure the values out, in this table when &lt;span class=&quot;math-container&quot;&gt;$\rho_1$&lt;/span&gt; is similar to &lt;span class=&quot;math-container&quot;&gt;$r_1$&lt;/span&gt;, utility of precipitation persistence is low.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Colorado is a mountainous area, so I could imagine large-scale wind direction aloft probably proves more significant than many areas.  For a location like Florida in the summer or Oklahoma in the spring, I'd imagine the skill is lower as persisting variables are less important.  Still, because humidity often varies more slowly, regularly controlled by air masses and large scale wind directions, which often are directed by large synoptic weather features, there will likely be at least some difference in the conditional probabilities in all locations/seasons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Don't know if that data is useful enough for your lecture purposes, but hopefully it offers a branch to seek into.  You may be able to dig up a few more similar tables by &lt;a href=&quot;https://journals.ametsoc.org&quot; rel=&quot;noreferrer&quot;&gt;searching on through research journal results in places like the AMS&lt;/a&gt; or, if need and desire be, could calculate such variables from station data &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/land-based-station-data&quot; rel=&quot;noreferrer&quot;&gt;available at sites like NCEI&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2018-10-15T15:22:46.550" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15349" PostTypeId="1" CreationDate="2018-10-15T15:51:02.777" Score="7" ViewCount="354" Body="&lt;p&gt;I am quite new to the psychrometry and the study of humidity, and I'm currently learning about the dry-bulb wet-bulb thermometry. As far as my understanding goes, the wet bulb is connected to a source of water (by a moist cloth or cotton swab) and the evaporation of the water to the air around it lowers the temperature to get the wet bulb.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can understand the concept here, but I believe I would need the heat capacity of the bulb to know the exact temperature drop in the wet bulb compared to the dry bulb. However, different thermometers may have different heat capacity and may show different wet bulb temperatures. How is this mitigated? How is the wet bulb temperature a constant value for a given relative humidity and dry bulb temperature despite the various heat capacities that may exist for the various thermometers used to measure the temperature?&lt;/p&gt;&#xA;" OwnerUserId="14054" LastEditorUserId="6031" LastEditDate="2021-07-19T10:37:47.197" LastActivityDate="2021-07-21T11:04:03.670" Title="How is the specific heat of a wet bulb determined?" Tags="|humidity|instrumentation|environmental-sensors|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15350" PostTypeId="2" ParentId="15347" CreationDate="2018-10-15T16:16:59.117" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://qualifications.pearson.com/content/dam/pdf/A%20Level/Mathematics/2017/specification-and-sample-assesment/Pearson%20Edexcel%20GCE%20AS%20and%20AL%20Mathematics%20data%20set%20-%20Issue%201%20(1).xls&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pearson publish a data set for A-level students&lt;/a&gt; (high school) that includes weather data from various locations. While the data set is (deliberately) flawed [one task for students is to identify flaws in the data set] it is &quot;real&quot; data and questions of persistence can be investigated with it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, in Heathrow, May-October 2015, there were 80 days on which it rained and forty days on which it rained, given it had rained the previous day. So at this time the probability of rain was about 0.43 and the conditional probability is about 0.50. So forecasting the weather based only on persistence gives a rather poor forecast.&lt;/p&gt;&#xA;" OwnerUserId="9563" LastActivityDate="2018-10-15T16:16:59.117" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15356" PostTypeId="2" ParentId="15340" CreationDate="2018-10-16T08:31:58.743" Score="5" Body="&lt;p&gt;Interesting question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As long as plate tectonics persists, then, as @Arkenstein mentions, mountain building and ocean basin formation will create enough topographical variety to ensure that land exists. Moreover, as long as there is a distinction between continental and oceanic lithosphere, we will have continents. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But this will not last forever. At some point, plate tectonics will stop as Earth's internal heat production falls. At this point, assuming nothing else happened, we would gradually see the mountains erode, and the sea fill up - slightly - with sediment.  Erosion stops at sea level, give or take, but sea level itself changes over time, so you might expect a world of very shallow seas where the continents used to be. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But that isn't the only thing going on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If plate tectonics stops, we would likely move to a Mars-style regime, with hotspots being the dominant mode of heat transport.  And as with Mars, we would see huge shield volcanoes form, basically like Iceland. So imagine an ocean planet with some massive circular islands dotted about, as the old continents eroded down. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, this won't actually happen; within about a billion years, the sun will get so hot that a runaway greenhouse effect will come into operation, and the oceans will evaporate, ending pretty much all life on earth, and the possibility of a global ocean. Indeed, with no mountains to draw down CO2 by erosion, a water world may be very unstable as regards runaway greenhouse effects.&lt;/p&gt;&#xA;" OwnerUserId="8217" LastActivityDate="2018-10-16T08:31:58.743" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15358" PostTypeId="1" CreationDate="2018-10-16T15:29:15.003" Score="0" ViewCount="321" Body="&lt;p&gt;I found this stone and I do not know what type of stone is this?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/6tH12.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6tH12.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14066" LastEditorUserId="2470" LastEditDate="2018-10-16T16:45:15.993" LastActivityDate="2018-10-16T17:43:15.587" Title="What kind of purple stone is this?" Tags="|geology|geophysics|rocks|geochemistry|mineralogy|" AnswerCount="1" CommentCount="0" ClosedDate="2019-09-07T00:39:12.730" ContentLicense="CC BY-SA 4.0" />
  <row Id="15359" PostTypeId="2" ParentId="15340" CreationDate="2018-10-16T17:03:36.553" Score="2" Body="&lt;p&gt;Note that you may have a bit of a misconception: the land heights/ocean depths, even what % of Earth is ocean, aren't too important because when land erodes, it doesn't fill in much of the depths, but instead raises the ocean bottom AND ocean top by similar amounts - the amount of water on Earth still needs somewhere to go!  It still just tends to sit on top of the land.  If you took a cup half filled with water, then dumped sand into the water, it doesn't take up all the water depth, but instead raises the water up in the cup:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xyMtV.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xyMtV.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The related question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7446/if-the-earth-were-a-smooth-spheroid-how-deep-would-the-ocean-be&quot;&gt;If the Earth were a smoothed spheroid, how deep would the ocean be?&lt;/a&gt; discusses how deep the oceans would be if the Earth became perfectly smoothed out and there were no change in the amount of mud (the question is, would the old sea bottom, now buried beneath the new dirt, then gradually lose some of its water?  I think the answer would be yes, but it's still true that a bit of the water may be permanently tied up into additional mud).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Erosion is indeed the process that would tend to smooth out the ground level.  However, anything that causes uneven vertical movement in the ground would work to counteract that.  Plate tectonics like mountain building and sinking plates would do so.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;So I think the answer is clear that in a tectonically inactive Earth... &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9488/how-much-water-is-the-atmosphere-losing-to-space&quot;&gt;if the Earth kept enough water during the process&lt;/a&gt;, we would eventually have an ocean-covered planet.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;But on the other hand I'd suspect for a 4.54 billion year old planet, if it weren't for tectonics, the Earth would probably already be long since smoothed out.  So it comes down to whether plate tectonics will slow down/change in the long run, which geologists can likely better discuss (and which may be a good separate question to ask).  But either way, there will be some important uncertainties [large meteor impacts, global temperatures changes, etc]&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;So I'd think the best answer may probably just be: not anytime soon!&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-10-16T17:36:54.433" LastActivityDate="2018-10-16T17:36:54.433" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15361" PostTypeId="2" ParentId="15358" CreationDate="2018-10-16T17:43:15.587" Score="7" Body="&lt;p&gt;That's amethyst, a violet version of quartz&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.m.wikipedia.org/wiki/Amethyst&quot; rel=&quot;noreferrer&quot;&gt;See here&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="13398" LastActivityDate="2018-10-16T17:43:15.587" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15362" PostTypeId="1" CreationDate="2018-10-16T18:44:02.083" Score="9" ViewCount="946" Body="&lt;p&gt;In comments on Earth changes due to global climate change, sea level changes is a common topic. I hear quotes about sea level changes in the centimeter and even millimeter range and wonder how such precision is even possible. The sea moves a lot; way more than a centimeter in a given day. I have no understanding how the sea level is measured, and I also can't even imagine how to do it with that kind of precision. How exactly to oceanographers measure sea level?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Perhaps a different question, I also can't envision a way that a measurement of 1 cm change is pragmatically meaningful, even for just a single beach, never mind a global average. A 1 cm higher tide I don't think would be noticed at most places. Even 10 cm could go unnoticed at many places. Does a 1 cm global average change mean anything useful? I guess rates of change can be alarming. 1 cm per year would add up over the decades.&lt;/p&gt;&#xA;" OwnerDisplayName="user14070" LastEditorDisplayName="user14070" LastEditDate="2018-10-17T18:47:51.900" LastActivityDate="2018-10-17T19:37:28.987" Title="How is sea level measured?" Tags="|ocean|oceanography|sea-level|tides|" AnswerCount="3" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="15363" PostTypeId="2" ParentId="13688" CreationDate="2018-10-16T20:28:11.740" Score="1" Body="&lt;p&gt;&lt;strong&gt;using R:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alright,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you have data with different resolution, I would suggest you to convert your data to raster and resample to match the grid cell of your wrf_inputs. Take care of mass conservation.&#xA;Then convert your raster to a matrix, data.frame, or spatial feature of 'POLYGON' your emissions&#xA;Then create wrf_chemi files&lt;/p&gt;&#xA;&#xA;&lt;p&gt;steps:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;raster your emissions &lt;/li&gt;&#xA;&lt;li&gt;raster your wrf_inputs&lt;/li&gt;&#xA;&lt;li&gt;resample emissions&lt;/li&gt;&#xA;&lt;li&gt;create data-frames of emissions&lt;/li&gt;&#xA;&lt;li&gt;create wrf_chemis your domains&lt;/li&gt;&#xA;&lt;li&gt;put your pollutants in wrf_chemis&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Please, read the documentation of each R Package&lt;/strong&gt;:&#xA;&lt;a href=&quot;https://CRAN.R-project.org/package=raster&quot; rel=&quot;nofollow noreferrer&quot;&gt;raster&lt;/a&gt;,&#xA;&lt;a href=&quot;https://ibarraespinosa.github.io/ratmos/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ratmos&lt;/a&gt;,&#xA;&lt;a href=&quot;https://r-spatial.github.io/sf/&quot; rel=&quot;nofollow noreferrer&quot;&gt;sf&lt;/a&gt;,&#xA;&lt;a href=&quot;https://atmoschem.github.io/vein/&quot; rel=&quot;nofollow noreferrer&quot;&gt;vein&lt;/a&gt;,&#xA;&lt;a href=&quot;https://atmoschem.github.io/eixport/&quot; rel=&quot;nofollow noreferrer&quot;&gt;eixport&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can raster your data by:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;library(raster)&#xA;devtools::install_github(&quot;ibarraespinosa/ratmos&quot;)&#xA;library(ratmos)&#xA;library(sf)&#xA;library(vein)&#xA;library(eixport)&#xA;r &amp;lt;- raster(&quot;emissions.tif&quot;) #or .nc, raster will use gdal to know&#xA;ri &amp;lt;- raster_wrf(&quot;wrfinput_d02&quot;)&#xA;spplot(ri, scales = list(draw = T)) # check plot&#xA;# Then it should be something like this&#xA;new_r &amp;lt;- crop(r, ri) # crop your data to the new raster&#xA;new_r &amp;lt;- resample(new_r, ri) #check options&#xA;df &amp;lt;- st_as_sf(rasterToPolygons(new_r))&#xA;# To create Array. Checkif you need to rotate your array&#xA;a &amp;lt;- GriddedEmissionsArray(df cols = ncol(ri), rows = nrow(ri), rotate = T) &#xA;# The create your wrfchemi&#xA; wrf_create('wrfinput', 'path_to_wrfchemi', ... , 'pollutants')&#xA;#and then put your emissions int the wrfchemi&#xA;wrf_put('path_to_wrfchemi', 'name_of_pollutant', a)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HUqHj.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HUqHj.png&quot; alt=&quot;wrfinput&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you need help, drop me an email sergio.ibarra@usp.br&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Best, Sergio&lt;/p&gt;&#xA;" OwnerUserId="6489" LastActivityDate="2018-10-16T20:28:11.740" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15365" PostTypeId="1" CreationDate="2018-10-16T23:54:42.550" Score="8" ViewCount="174" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/UdXSv.jpg&quot; alt=&quot;Tropical Cyclone tracks from 1945 to 2006, showing a distinct gap at the equator&quot;&gt;&#xA;Image by &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Tropical_cyclones_1945_2006_wikicolor.png&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia user Citynoise&lt;/a&gt; using NOAA data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you look at this map of tropical cyclone tracks, you'll notice that there's a gap in the central northern Pacific where tropical cyclones generally don't go.  On the edge of that gap, you'll find the Hawaiian Islands.  Further, although the islands are sort of in the fringes of the eastern tropical cyclone area, they're in a gap in that fringe -- tropical cyclones forming in the eastern Pacific track either north or south of them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, why don't tropical cyclones hit Hawaii?&lt;/p&gt;&#xA;" OwnerUserId="2643" LastActivityDate="2018-10-17T14:59:00.800" Title="Why don't tropical cyclones hit Hawaii?" Tags="|meteorology|tropical-cyclone|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15366" PostTypeId="1" AcceptedAnswerId="15401" CreationDate="2018-10-17T00:34:41.247" Score="3" ViewCount="95" Body="&lt;p&gt;The Earther.Gizmodo.com article &lt;a href=&quot;https://earther.gizmodo.com/scientists-discover-a-weird-noise-coming-from-antarctic-1829793363&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scientists Discover a Weird Noise Coming From Antarctic Ice Shelf&lt;/a&gt; links to the American Geophysical Union video (an more importantly &lt;em&gt;audio&lt;/em&gt;) (AGU) &lt;a href=&quot;https://www.youtube.com/watch?v=w56RxaX9THY&quot; rel=&quot;nofollow noreferrer&quot;&gt;This is what an Antarctic Ice Shelf sounds like&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It also links to the recently published Geophysical Research Letter (Chaput et al. 2018) &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL079665&quot; rel=&quot;nofollow noreferrer&quot;&gt;Near‐Surface Environmentally Forced Changes in the Ross Ice Shelf Observed With Ambient Seismic Noise&lt;/a&gt; (open access) from where the image below is taken.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT:&lt;/strong&gt; In the same issue there is a commentary: &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2018GL080366&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seismology Gets Under the Skin of the Antarctic Ice Sheet&lt;/a&gt; which was written by &lt;a href=&quot;https://news.agu.org/press-release/antarctic-ice-shelf-sings-as-winds-whip-across-its-surface&quot; rel=&quot;nofollow noreferrer&quot;&gt;Douglas MacAyeal, a glaciologist at the University of Chicago who was not connected to the new study&lt;/a&gt; which I also do not understand!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Dimensional analysis alone suggests that a length scale of the phenomenon resulting in these slightly sub-sonic oscillations can be obtained from speed divided by frequency (e.g. m/s divided by 1/s) but using the speed of sound in ice or water (roughly 4,000 and 1,500 m/s respectively) and circa 10 Hz suggests a length scale of a few hundred meters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The paper itself is quite technical and in depth. Somewhere in there, is there a physical distance in water, or in ice that corresponds to this frequency, or are the oscillation frequencies due to a dynamic process like sticking and slipping, rather than to the propagation speed of sound?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ash7C.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ash7C.jpg&quot; alt=&quot;Figure 3, Chaput et al. 2018&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Caption of Figure 3:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;(a) Marginal PPD for Vp and Vs for the premelt resonances at station DR09, obtained by MCMC inversion of power spectra (See Suppl. S4: 1‐D MCMC inversion, Capelli et al., 2016). The red curves indicate the marginal posterior mean for P and S velocities. (b) Top panel, representative subset of power spectral models (red curves) from the PPD in (a) for station DR09, compared with the observed premelt spectrum (blue curve). Bottom panel, averaged observed premelt and postmelt spectral resonances (blue and green curves, respectively) at DR09. (1) and (2) indicate the position of a higher frequency peak of interest before and after the melt event. (c) Contour plot depicting a grid search of penetration depth versus velocity perturbation applied to the premelt model (peak pattern (1), in b), and fit to the postmelt resonance peak pattern, as denoted by peak pattern (2) in (b), lower panel. The minimum with respect to a least squares fit is represented by the red star, denoting a 35–40% perturbation with a depth penetration of 3–4 m. The premelt model used here is the mean posterior model shown in (a). (d) Example frequency peak response to a 40% velocity drop with varying degrees of depth penetration for the DR09 premelt velocity model in (a). Note that lower frequency spectral peaks can be nearly unaffected if the perturbation depth is shallow. (1) and (2) denote observed premelt and postmelt peaks plotted in (b). PPD = Posterior Probability Distributions; MCMC = Markov chain Monte Carlo.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2018-10-21T08:42:19.957" LastActivityDate="2018-10-21T11:16:45.213" Title="Simple way to understand these narrow frequency peaks in recently published &quot;ice shelf singing&quot;?" Tags="|geophysics|antarctic|ice|glacier|arctic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15369" PostTypeId="2" ParentId="15362" CreationDate="2018-10-17T14:51:48.117" Score="8" Body="&lt;p&gt;There are two main approaches to measuring sea level (and thus its change): local and satellite-based.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To measure local sea level we can set up gauges on the coast that record the water level every so often - hourly is common. These use various methods, which have evolved over time, all aimed at having a very precise (sometimes down to millimetres) long-term record at that location. In the UK, the &lt;a href=&quot;https://www.bodc.ac.uk/data/hosted_data_systems/sea_level/uk_tide_gauge_network/&quot; rel=&quot;nofollow noreferrer&quot;&gt;UK Tide Gauge network&lt;/a&gt; has records going back (in some locations) to 1915.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mechanisms of tide gauges vary, and have improved over time. Early ones used floats inside a &quot;stilling well&quot; (a column of water that protects the gauge from waves). Some modern gauges work by sensing water pressure. If we have good measurements of temperature and salinity we can calculate density, and if we know density and the pressure at a location, we can calculate the amount of water above that location. Other modern gauges use ultrasound or radar transceivers located at a known vertical position above the water, and thus measure the distance to the water surface with very high accuracy. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These records of water level include the tides, of course, as well as other influences such as the effects of changing air pressure, wind driven currents, and so forth. They are also affected by the rising and falling of land over time. These effects can all be accounted for, and removed from the signal, and effort goes into doing this. You might some interesting reading on the topic from the &lt;a href=&quot;https://www.ntslf.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Tidal and Sea Level Facility&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, no matter how good the record from fixed tide gauges, they can only tell us what is happening on the coast. While that's arguably the most important for mankind, it's hardly a global picture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other approach that we can take is satellite observations. Radar altimeters on satellites can, and do, measure sea level worldwide to a precision of a few centimetres or better. &lt;a href=&quot;https://sealevel.jpl.nasa.gov/missions/jason3/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This&lt;/a&gt; is a recent mission for this purpose (there may have been others since - I'm not an expert). The level of accuracy here is not as good, but it can be improved statistically through a large number of measurements. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The greater difficulty with satellite altimetry is removing the tides, because the satellites are always moving over the earth's surface and so can only measure any one location at relatively infrequent intervals. Consequently, some sophisticated global tidal models are used with data provided by the satellites to (a) improve the models, for people who want to predict tides, and (b) use the tides from the models to remove the tides from the satellite measurements, leaving just longer-term changes in sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think part of the intent of your question is &quot;people quote changes in sea level of millimetres or centimetres per year, yet surely the measurements are not this accurate?&quot;. Well, satellite measurements aren't, though local ones might be, but remember that we're measuring for more than just one year. One approach might be to look at a ten- or twenty-year trend, and work out the average change per year from that.&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2018-10-17T19:33:28.093" LastActivityDate="2018-10-17T19:33:28.093" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15370" PostTypeId="2" ParentId="15365" CreationDate="2018-10-17T14:59:00.800" Score="3" Body="&lt;p&gt;There are at least two effects are at play here: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Hawaii is a tiny speck of land in a big ocean; the odds of hitting any given spot in the Pacific with a storm in any given season is incredibly low.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The waters around Hawaii are deep and generally relatively cold, they suck energy out of storm systems that pass over them causing cyclones to downgrade into tropical depressions before they hit the islands, so there are plenty of storms but few are still cyclone grade when they arrive.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2018-10-17T14:59:00.800" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15371" PostTypeId="2" ParentId="15362" CreationDate="2018-10-17T17:37:12.320" Score="6" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;How exactly to oceanographers measure sea level?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;By a number of mechanisms, some direct, others indirect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Various government agencies such as NOAA operate coastal tidal stations that measure local sea level height. There are about a thousand of these worldwide. In addition to these official tidal stations, there are even more private stations such as those on offshore drilling platforms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other measurements come from buoys, some anchored, others adrift. There are almost 5000 drifting ARGO buoys alone. The ARGO buoys measure temperatures at various depths. Since warmer water is less dense than is cooler water, rising ocean temperatures are a key contributor to sea level rise, about 1/3 of the total.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yet other measurements come from space. The remaining 2/3 of sea level rise results from added mass to the oceans. This added mass can be measured by high precision gravity experiments such as those by the GRACE satellites. Those precise measurements in the changes in Earth's gravity field enables precise orbit determination of other satellites, some of which carry radar altimeters. Those altimeter readings, coupled with high precision orbit determinations, provide yet another mechanism for assessing sea level change.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-10-17T17:37:12.320" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15372" PostTypeId="2" ParentId="15362" CreationDate="2018-10-17T19:37:28.987" Score="5" Body="&lt;p&gt;(adding this as a separate answer as it's answering a different part of the question - one that wasn't there when I did my first answer...)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To understand why a rise in sea level of as little as 10cm can be significant:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Imagine a place that floods occasionally. Maybe just once a year, or less. Now think about how often it &lt;em&gt;almost&lt;/em&gt; floods - where the water stops just 5cm below the top of the wall. Those occasions don't get reported in the same way, but they are probably much more frequent than the times when it actually floods. So a modest increase in sea level could have serious implications for many coastal areas - especially in generally low-lying countries such as the Netherlands or Bangladesh (one of those can afford to raise its walls; the other can't)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, remember that while we're dealing with millimetres per year at the moment, the concern that many climate scientists have is not about a few centimetres - it's about a few &lt;em&gt;metres&lt;/em&gt;. At that level, most of the coast cities in the USA are flooded.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2018-10-17T19:37:28.987" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15375" PostTypeId="1" AcceptedAnswerId="15377" CreationDate="2018-10-18T01:00:07.223" Score="3" ViewCount="961" Body="&lt;p&gt;These are recent pictures of it. It’s heavy, I see small minerals that catch the light in it, very bumpy, spherical, doesn’t seem to be magnetic, I was falling down a deep trench and kicked it up at the bottom. Area was sand, sage, and small cacti. (&lt;a href=&quot;https://i.stack.imgur.com/p2Bbz.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://i.stack.imgur.com/p2Bbz.jpg&lt;/a&gt;)&lt;img src=&quot;https://i.stack.imgur.com/UF3HY.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4h4eE.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/w6yNc.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="14079" LastActivityDate="2018-10-18T06:17:35.260" Title="I found this strange spherical stone in Gillette Wyoming. I have no idea what it is. Please help." Tags="|geology|rocks|mineralogy|minerals|" AnswerCount="2" CommentCount="0" ClosedDate="2019-09-07T00:39:48.513" ContentLicense="CC BY-SA 4.0" />
  <row Id="15376" PostTypeId="2" ParentId="15375" CreationDate="2018-10-18T01:36:51.427" Score="2" Body="&lt;p&gt;That is a very cool rock. However, mineralogically, it is probably not all that interesting. It is likely a sedimentary nodule that formed from concreted sand and organics. The strange shape is likely the result of differential weathering, where one half of the nodule was exposed, while the other side was protected due to burial.&lt;/p&gt;&#xA;" OwnerUserId="14045" LastActivityDate="2018-10-18T01:36:51.427" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15377" PostTypeId="2" ParentId="15375" CreationDate="2018-10-18T06:17:35.260" Score="4" Body="&lt;p&gt;This is a so called Moqui Marble. A spherical concretion formed by sand and iron based minerals like limonite. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://de.m.wikipedia.org/wiki/Moqui-Marble&quot; rel=&quot;nofollow noreferrer&quot;&gt;Further information can be found here&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="13398" LastActivityDate="2018-10-18T06:17:35.260" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15379" PostTypeId="1" CreationDate="2018-10-18T11:58:31.817" Score="16" ViewCount="22303" Body="&lt;p&gt;It is often explained that warm air holds more water because warmer water is less likely to condense. This and other explanations just seem to be circular arguments.  If the warmer air picks up enough moisture it will saturate and then water will still condense at 100% humidity.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given two cubic feet of air with one warmer than the other and the warmer holding more water, where/how do all those extra water molecules invisibly fit in the warmer cubic foot? What is the deep physics or chemistry reason this happens?&lt;/p&gt;&#xA;" OwnerUserId="14081" LastActivityDate="2023-01-17T01:59:42.473" Title="Why does warm air &quot;hold&quot; more moisture?" Tags="|atmosphere|humidity|air|" AnswerCount="4" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15380" PostTypeId="2" ParentId="15379" CreationDate="2018-10-18T14:50:53.550" Score="17" Body="&lt;p&gt;Saying that warm air &quot;holds&quot; more moisture is technically incorrect, but is a common colloquialism. Let's break it down to the technicalities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's consider a glass of water with a vacuum (no air) above it. What will happen? The molecules that are at the top most layer of the water will evaporate. At what rate will the water evaporate? Better yet, what is evaporation?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Evaporation is when the water molecules gain enough kinetic energy (how fast they vibrate) to break the bonds that hold them to one another. Kinetic energy is dependent on temperature. So the molecules vibrate faster, break their bonds, and enter the vacuum as a vapor. Some molecules will stay as a vapor in the vacuum, but others will reenter the liquid. When the molecules enter the liquid as fast as they are leaving, then it is saturated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the air is cooled down, then the rate at which molecules leave the liquid slows down. The molecules entering the liquid do not slow down at the same rate, causing the liquid to grow toward it's initial state.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that I specifically said it is a vacuum. Instead of a glass of water, picture the water as little drops. The atmosphere can act to warm or cool these drops, and vice-versa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the more nitty-gritty aspect of this, the equation that describes the vapor pressure as a function of temperature is called the Clausius-Clapeyeron equation/relation. The American Meteorological Society has &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Clausius-clapeyron_equation&quot; rel=&quot;noreferrer&quot;&gt;one approximate solution&lt;/a&gt;, but &lt;a href=&quot;http://www.theweatherprediction.com/habyhints2/646/&quot; rel=&quot;noreferrer&quot;&gt;I prefer this equation&lt;/a&gt;: &lt;span class=&quot;math-container&quot;&gt;$$e_{sat}(T)=611 Pa \exp[\frac{L_v}{R_v}(273.15^{-1}-T^{-1})]$$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$L_v$&lt;/span&gt; is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Enthalpy_of_vaporization#Other_common_substances&quot; rel=&quot;noreferrer&quot;&gt;latent heat of vaporization&lt;/a&gt;, &lt;span class=&quot;math-container&quot;&gt;$R_v$&lt;/span&gt; is the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Gas_constant&quot; rel=&quot;noreferrer&quot;&gt;specific gas constant for water vapor&lt;/a&gt;, and &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; is the absolute temperature in Kelvin. Combined with the ideal gas law for water vapor (assuming saturation) &lt;span class=&quot;math-container&quot;&gt;$$e_{sat}(T)V=m_vR_vT$$&lt;/span&gt;, and given the volume (&lt;span class=&quot;math-container&quot;&gt;$V$&lt;/span&gt;) we can write an expression for the mass of water vapor &lt;span class=&quot;math-container&quot;&gt;$m_v$&lt;/span&gt;. The equation comes out to &lt;span class=&quot;math-container&quot;&gt;$$m_v=611 Pa \exp[\frac{L_v}{R_v}(273.15^{-1}-T^{-1})]V R_v^{-1}T^{-1}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer your final question, the molecules are approximated as being infintessimally small, per &lt;a href=&quot;https://en.wikipedia.org/wiki/Ideal_gas_law&quot; rel=&quot;noreferrer&quot;&gt;the ideal gas law&lt;/a&gt;. To be more specific, one molecule of water is about &lt;a href=&quot;http://www.mc3cb.com/pdf_chemistry/What%20is%20the%20diameter%20of%20a%20water%20molecule.pdf&quot; rel=&quot;noreferrer&quot;&gt;7.08&lt;span class=&quot;math-container&quot;&gt;$\times$&lt;/span&gt; 10&lt;span class=&quot;math-container&quot;&gt;$^{-19}$&lt;/span&gt; cubic feet&lt;/a&gt; (after some math), so the added volume is considered negligible. In short, the molecules are treated as point masses.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2018-10-18T15:27:53.790" LastActivityDate="2018-10-18T15:27:53.790" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15381" PostTypeId="1" AcceptedAnswerId="15389" CreationDate="2018-10-18T15:07:25.693" Score="15" ViewCount="680" Body="&lt;p&gt;The recent BBC News article &lt;a href=&quot;http://www.bbc.com/future/story/20181016-why-india-wants-to-turn-its-beaches-into-nuclear-fuel&quot; rel=&quot;nofollow noreferrer&quot;&gt;Why India Wants to Turn its Beaches into Nuclear Fuel&lt;/a&gt; includes the passage:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The tropical beaches of India probably bring to mind sun-dappled palms, fiery fish curries and dreadlocked backpackers, &lt;strong&gt;but they also hold a surprising secret. Their sands are rich in thorium – often hailed as a cleaner, safer alternative to conventional nuclear fuels&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The country has long been eager to exploit its estimated 300,000 to 850,000 tonnes of thorium – quite probably the world’s largest reserves – but progress has been slow.  Their effort is coming back into focus amid renewed interest in the technology. Last year Dutch scientists fired up the first new experimental thorium reactor in decades, start-ups are promoting the technology in the West and last year China pledged to spend $3.3bn to develop reactors that could eventually run on thorium.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The caption to a stock image of a beach says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Kerala's beautiful beaches hold 16% of India's thorium reserves&lt;/strong&gt;, a major potential power source - if only scientists can find the right way to exploit it.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; why would India have so much thorium on its beaches, apart from the fact that India has so many beaches of course?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2020-11-04T08:35:51.710" LastActivityDate="2020-11-04T08:35:51.710" Title="Why would India have so much thorium on its beaches?" Tags="|mineralogy|mining|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15382" PostTypeId="2" ParentId="15379" CreationDate="2018-10-18T16:21:22.333" Score="6" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;What is the deep physics or chemistry reason this happens?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In one word, entropy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a thousand words (i.e., a picture),&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/o004H.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/o004H.png&quot; alt=&quot;Phase diagram of water&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sub&gt;Source: Wikipedia article on &lt;a href=&quot;https://en.wikipedia.org/wiki/Phase_diagram&quot; rel=&quot;noreferrer&quot;&gt;Phase Diagram&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The above is a phase diagram of water. The curve of interest is that between vapor (tan area) and solid or liquid (blue and green areas). For a given temperature (a vertical line in the diagram), it is entropically favorable for water to be solid or liquid when the partial pressure of water vapor is above the sublimation/vaporization curve, but it is entropically favorable for water to be vapor when the partial pressure is below the curve.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note well: The pressure of interest is the partial pressure of water vapor, not the pressure of the air as a whole. On the other hand, the temperature of the air does dictate the temperature of the water vapor that is present. Also note well: The above diagram is for a flat surface. Small water droplets have a high surface tension, which increases the effective saturation pressure in very clean air. (This is, for example, why snowflakes almost always have a tiny grain of dust at their centers.) Nonetheless, the effective saturation pressure follows the same form: It increases with increasing temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You asked for a deep physics reason for why this happens. Suppose the surface between water ice or liquid water and water vapor is at equilibrium; i.e., the air is the saturated with water vapor. The water vapor molecules have a speed distribution approximately given by the Maxwell–Boltzmann distribution. Some water vapor molecules will be moving slower than others. Those slow-moving molecules that hit the surface are more likely to be absorbed by the surface than are those molecules that are moving faster. The molecules in the ice or liquid water are also vibrating / moving at different speeds. The fast moving solid/liquid water molecules are more likely to escape the surface than are those that are moving slower. Under equilibrium conditions, the rates at which vapor molecules are captured and ice/liquid molecules escape are equal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Raising the temperature of the solid/liquid and of the vapor means fewer vapor molecules will be moving slow enough to be captured while more solid/liquid will be moving fast enough to escape. This increases the pressure at which equilibrium occurs. Lowering the temperature similarly decreases the pressure at which equilibrium occurs.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-10-18T16:21:22.333" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15386" PostTypeId="2" ParentId="15379" CreationDate="2018-10-18T22:20:11.687" Score="8" Body="&lt;p&gt;The water molecule is just another molecule in the atmosphere - except that it's triatomic, whereas 99.97% of the dry atmosphere is monatomic (Argon) and diatomic (Oxygen and Nitrogen). It's also slightly electrically polarized, and because of this it has a low energy state when in the presence of similar molecules (liquid or solid form), and at a higher temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So &quot;Why doesn't all the water vapor simply fall out of the air?&quot; What's keeping these molecules in the the vapor state is simply the energy of motion. Cool the atmosphere (remove this energy) and the water vapor will be allowed to return to its lower energy state. The same thing will happen with all the other atmospheric constituents - just at different temperatures and pressures.&lt;/p&gt;&#xA;" OwnerUserId="6313" LastActivityDate="2018-10-18T22:20:11.687" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15388" PostTypeId="2" ParentId="9089" CreationDate="2018-10-19T03:25:43.357" Score="0" Body="&lt;p&gt;Burning wood for home heating could actually be a carbon credit.  Wood offsets combustion of oil, natural gas, propane, and the use of coal fired generation of electricity.  Wood left to rot, as the previous post note, is carbon neutral.&lt;/p&gt;&#xA;" OwnerUserId="14094" LastActivityDate="2018-10-19T03:25:43.357" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15389" PostTypeId="2" ParentId="15381" CreationDate="2018-10-19T09:19:03.000" Score="19" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;why would India have so much thorium on it's beaches...?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Because &lt;a href=&quot;https://geology.com/minerals/monazite.shtml&quot; rel=&quot;noreferrer&quot;&gt;monazite&lt;/a&gt;. Monazite is a rare earth element phosphate, with the formula CePO&lt;sub&gt;4&lt;/sub&gt; (where Ce stands not only for cerium, but all of the are earth elements and yttrium as well). It is one of the main ore minerals for the rare earths. It's a very common mineral in granites and similar rocks, and it's very resistant to erosion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, it commonly accumulates in &lt;a href=&quot;https://en.wikipedia.org/wiki/Placer_deposit&quot; rel=&quot;noreferrer&quot;&gt;placer deposits&lt;/a&gt;, together with other resistant minerals such as quartz, magnetite, zircon, rutile, etc. Essentially, nature breaks down the rocks and concentrates those minerals in &lt;a href=&quot;https://en.wikipedia.org/wiki/Heavy_mineral_sands_ore_deposits&quot; rel=&quot;noreferrer&quot;&gt;mineral sands&lt;/a&gt; (sometimes known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Black_sand&quot; rel=&quot;noreferrer&quot;&gt;black sands&lt;/a&gt;). These sands are not unique to India, and many examples can be found across the world. Essentially you find them where ever you have sandy beaches developed in areas of granite mountains (in the case of monazite).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why thorium? Because monazite shares the same crystal structure with a mineral called &lt;a href=&quot;https://www.mindat.org/min-6865.html&quot; rel=&quot;noreferrer&quot;&gt;cheralite&lt;/a&gt;: CaTh(PO&lt;sub&gt;4&lt;/sub&gt;)&lt;sub&gt;2&lt;/sub&gt;, and the two components (monazite and cheralite) can exist in the same mineral via &lt;a href=&quot;https://en.wikipedia.org/wiki/Solid_solution&quot; rel=&quot;noreferrer&quot;&gt;solid solution&lt;/a&gt;. Some monazites can contain 20 and 30% thorium! Granite-derived monazite is particularly rich in Th, unlike carbonatite-derived monazite which usually has little Th. The Th is usually an unwanted by-product, with monazite mined primarily for the rare earths. But, if you're looking for the Th - this is something that you actually want.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2018-10-19T10:03:57.907" LastActivityDate="2018-10-19T10:03:57.907" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15391" PostTypeId="1" CreationDate="2018-10-19T23:26:13.770" Score="5" ViewCount="44" Body="&lt;p&gt;I hope that you can help me, my wife and I visited National Trust - Stackpole, Pembrokeshire last week where I took a couple of hundred photos.&lt;br&gt;&#xA;I've attached a photo of the coloured cliffs there.  For me to enter this into one of our club competitions I need to know the correct terminology for the rock formation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zlYle.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zlYle.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope that there is a someone who could let me know&lt;/p&gt;&#xA;" OwnerUserId="14099" LastEditorUserId="6298" LastEditDate="2018-10-20T04:41:38.620" LastActivityDate="2018-10-20T06:00:36.057" Title="Identification of rock formation along Wales coast" Tags="|regional-geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15392" PostTypeId="2" ParentId="15391" CreationDate="2018-10-20T06:00:36.057" Score="4" Body="&lt;p&gt;This is Marloes Sand Beach, a classical fossil site. The nicely colored rocks are sandstones of the Silurian age (around 425 million years old). The different dipping angles of the sandstone layers are a result of tectonic processes, which were folding the rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.de/amp/s/ukfossils.co.uk/2007/10/26/marloes-sands&quot; rel=&quot;nofollow noreferrer&quot;&gt;Further information about Marloes Sand can be found here&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="13398" LastActivityDate="2018-10-20T06:00:36.057" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15396" PostTypeId="1" CreationDate="2018-10-20T13:04:50.310" Score="1" ViewCount="244" Body="&lt;p&gt;Found these Pebbles at a lake edge where a Serpentinite belt runs through, there are lots of serpentine pebbles along this lake in Co. Sligo Ireland.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/e5IWs.jpg&quot; alt=&quot;enter image description here&quot;&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/HFmSr.jpg&quot; alt=&quot;enter image description here&quot;&gt;&#xA;The larger pebble is 1 5/8'' a Yellowish white color underneath and translucent, and has a tiny pitted surface The smaller pebble is opaque.&lt;/p&gt;&#xA;" OwnerUserId="12459" LastEditorUserId="6467" LastEditDate="2018-10-20T14:16:54.437" LastActivityDate="2018-10-21T15:07:23.553" Title="What are these Pebbles" Tags="|geology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15398" PostTypeId="2" ParentId="8385" CreationDate="2018-10-20T19:45:06.183" Score="1" Body="&lt;p&gt;When I watch wind travel across a grass plain,  the top of the grass like like a wave.  So if the movement of wind applied a consistently constant force,  the grass would just all lean consistently across the field until the wind died.  Instead,  the grass waves lengthen and narrow according to the speed or degree of force of the wave trough. &lt;/p&gt;&#xA;" OwnerUserId="14105" LastActivityDate="2018-10-20T19:45:06.183" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15399" PostTypeId="2" ParentId="7855" CreationDate="2018-10-20T20:15:49.470" Score="1" Body="&lt;h1&gt;In a Sentence:&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;For a planet to have an ionosphere, we would expect it to have a pressure of at least 1 bar (&quot;thick enough&quot;) and to have a host star producing sufficient high-energy photons. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Background&lt;/h1&gt;&#xA;&#xA;&lt;h3&gt;Generation of an Ionosphere&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;The ionosphere is a balance between plasma production and plasma loss. The primary source of &lt;em&gt;ionization&lt;/em&gt; (photons getting absorbed by an atom or molecule, knocking off an electron), is usually high-energy photons. The primary source of &lt;em&gt;recombination&lt;/em&gt; (ionized atom or molecule picks up an electron, causing the particle to be charge-neutral), is usually collisions between particles. The chemical composition of the atmosphere definitely influences this balance, too. When there's more ionization, the ionosphere grows. When there's more recombination, the ionosphere shrinks. It can be shrinking at one location and growing in another (see Planetary Rotation, below, for an example). &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Location of an Ionosphere&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;High above the ionosphere, the gas density is low enough that most of the light from a planet's host star travels through the atmosphere without interacting with (i.e. ionizing) the atmosphere. As the light travels downward through the atmosphere, the atmospheric density increases, which causes more high-energy radiation --- particularly extreme ultraviolet (EUV) --- to be absorbed by the atmosphere, causing ionization (plasma generation). Travelling deeper still, the density increases exponentially, but at this depth, most of the high-energy photons have already been absorbed, so there's little ionization happening. Moreover, at this depth, any ions are short-lived due to frequent collisions with the neutral atmosphere that lead to recombination (plasma depletion). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ionosphere is therefore a &quot;Goldilocks&quot; region in a planet's atmosphere: low enough in the atmosphere for there to be plenty of molecules to absorb high-energy photons, but still high enough that there's still plenty of high-energy radiation from the host star and tenuous enough for recombination to not dominate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a &lt;em&gt;very general&lt;/em&gt; rule of thumb, roughly &lt;span class=&quot;math-container&quot;&gt;$1/e$&lt;/span&gt; of incoming light gets absorbed above the 1 bar pressure level in an atmosphere. (Of course, this varies with wavelength, chemistry, and more....) This is a relatively high fraction of light that has been absorbed, but it's deep enough that collisions between particles are frequent enough for recombination to be more frequent than ionization. Any particles that get ionized quickly become neutralized. Based on this alone (but also substantiated by studies of Earth and other planets), we may conclude that the ionosphere is somewhere above the 1 bar pressure level, but this can vary.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Criteria&lt;/h1&gt;&#xA;&#xA;&lt;h3&gt;An Atmosphere&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Without an atmosphere, there aren't any molecules to ionize. Therefore, one needs an atmosphere to have an ionosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since ionospheres tend to be above the 1 bar pressure level (at least in our Solar System), we may guess that a planet needs to have at least 1 bar of pressure in order to have an ionosphere.  &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;A Consistent Source of Radiation&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Without high-energy radiation, the atmosphere will not naturally ionize. Usually, this is a host star. (One could also imagine far-fetched sci-fi scenarios with artificially-generated ionospheres....) The host star has to produce sufficient amounts of high-energy photons to irradiate the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I added the word &quot;consistent&quot; to this section. The reason is because if the star &quot;turned off&quot; (or went through a phase where it produced insufficient EUV photons), then charge recombination would slowly dissipate the ionosphere. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Other Factors&lt;/h1&gt;&#xA;&#xA;&lt;h3&gt;Proximity to Host Star / Star Type&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Either a cooler host star or the planet being further from the star will cause it to receive less of the high-energy required for ionization. The opposite is also true.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Receiving less radiation means that the fraction of molecules in the ionosphere that get ionized is smaller, leading to a &quot;weak ionosphere&quot; (i.e. one that is weakly ionized). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a planet receiving more radiation, the ionosphere will be stronger and thicker for two reasons. First, the higher irradiation means that the few molecules at higher altitudes have more chances to ionize, meaning the ionosphere can be taller than it would otherwise be. Second, because there's more radiation, even though &lt;span class=&quot;math-container&quot;&gt;$1/e$&lt;/span&gt; gets absorbed above the 1 bar pressure level, there's still a ton of radiation that hasn't been absorbed. Because of this, the ionosphere can be deeper than it would otherwise be. &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Chemical Composition&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Different chemical composition could allow an ionosphere to be different than what I've described above. For example, if a planet's atmosphere is primarily composed of a gas that doesn't absorb EUV well, then much of the EUV will penetrate deeper into the atmosphere and would cause the ionosphere to be weaker and/or located deeper in the atmosphere. Or, for a planet with an atmosphere that absorbs EUV extremely well, the ionosphere might be higher in the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short, the chemistry of the atmosphere can make the ionosphere be located higher or lower in the atmosphere, or cause it to be more strongly- or weakly-ionized.&lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Planetary Rotation&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Earth's ionosphere varies from day to night. At local noon, the ionosphere facing the host star receives the maximum incident radiation, causing more ionization and a thicker/stronger ionosphere. At night, the atmosphere receives essentially no ionizing photons, so recombination makes the ionosphere weaker and thinner. (For the same reason, a planet can have seasonal variations as well.) &lt;/p&gt;&#xA;" OwnerUserId="4439" LastEditorUserId="4439" LastEditDate="2018-10-20T21:05:52.437" LastActivityDate="2018-10-20T21:05:52.437" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15400" PostTypeId="1" AcceptedAnswerId="15442" CreationDate="2018-10-20T21:05:25.803" Score="5" ViewCount="370" Body="&lt;p&gt;I have a theoretical exercise where I calculated the amount of CO2 that is released to the atmosphere per year (4.6 ppm). We assume that the relative increase of CO2 is 2 ppm, hence the percentage of CO2 that stays in the atmosphere is around 2/4.6 ~ 40 %.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the technical term for this percentage?&lt;/p&gt;&#xA;" OwnerUserId="14043" LastActivityDate="2018-10-27T11:59:46.970" Title="Technical term for percentage of CO2 remaining in the atmosphere" Tags="|atmosphere|climate-change|co2|climatology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15401" PostTypeId="2" ParentId="15366" CreationDate="2018-10-21T10:03:55.957" Score="4" Body="&lt;p&gt;The wavelengths that travel through the ice have a faster speed of travel, and the physical size of the pressure variations that cause the sound are not 100 meters. It's more like 1 meter, so it's similar to having an oversized speaker cone blasting air waves into the ice, which the ice then transmits to the microphone most clearly at a depth of 1-2 meters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The best illustration I can find of pressure differentials and resonance modes from wind, of about 5-15 hz are from this 1960's YouTube video:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://youtu.be/TqTSyFz6DJc?t=176&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://youtu.be/TqTSyFz6DJc?t=176&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The frequencies of the speaker cones are guided by air turbulence buffeting from the angles of the snow dunes and the wind, which generate 1/2/3 frequencies, perhaps from 1/2/3 different snow dunes types in the same area, depending on the local dune shapes, and when a storm changes the dune shapes, the frequencies change correspondingly. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KONZA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KONZA.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The compressed snow has an elastic property which absorbs higher frequencies at depth and adds higher waves together to form lower waves, so the frequency sounds lower in the ice. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's not probable that the frequencies are generated by 100 meter wide diaphragms and pressure differentials because that would correspond to very high dunes and long valleys. the high dunes are not likely, and the wind pressure events in the valleys would not generate major pressure differentials.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I was a bob moog, and I wanted to copy the physical resonance process of the dunes, It would be a relatively easy synthesizer to design. They have place bass audio cones at different zones of the dune at different times, and measure a 3D map of frequencies and timings from a zone near the artificial sound generator. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The unclear statements of the article say that:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They measured Perturbation Velocity, a coefficient of flow dynamics for seizmology and of aerodynamics turbulance equations for physics? which kind of perturbation velocity is implied? Where are the equations for perturbation velocity and what a the name of the equations?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sound propagates through the firn layer, a study which may have already been measured and demonstrated by other snow and ice physicists? Sounds travel through snow, ice and water for different distances. To what distance and efficiency does firn transmit sound? there are graphs for snow acoustics and some of the research is hilarious:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://rspa.royalsocietypublishing.org/content/471/2177/20140988&quot; rel=&quot;nofollow noreferrer&quot;&gt;one of the most complex pages of research i have ever seen&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;from this page: &lt;a href=&quot;https://www.google.fr/search?q=sound+propagation+in+ice&amp;amp;num=100&amp;amp;source=lnms&amp;amp;tbm=isch&amp;amp;sa=X&amp;amp;ved=0ahUKEwjYptm3s5feAhVLOBoKHa2sBpEQ_AUIDigB&amp;amp;biw=1572&amp;amp;bih=808&amp;amp;dpr=1.5#imgrc=1z-RRNglm0UEGM&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.google.fr/search?q=sound+propagation+in+ice&amp;amp;num=100&amp;amp;source=lnms&amp;amp;tbm=isch&amp;amp;sa=X&amp;amp;ved=0ahUKEwjYptm3s5feAhVLOBoKHa2sBpEQ_AUIDigB&amp;amp;biw=1572&amp;amp;bih=808&amp;amp;dpr=1.5#imgrc=1z-RRNglm0UEGM&lt;/a&gt;:&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2018-10-21T11:16:45.213" LastActivityDate="2018-10-21T11:16:45.213" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15402" PostTypeId="2" ParentId="15396" CreationDate="2018-10-21T15:07:23.553" Score="3" Body="&lt;p&gt;The white one is milky quartz, the yellowish/brownish one could be some variation of quartz or quartzite, too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.m.wikipedia.org/wiki/Quartz#Milky_quartz&quot; rel=&quot;nofollow noreferrer&quot;&gt;Further information about quartz and milky quartz can be found here&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="13398" LastActivityDate="2018-10-21T15:07:23.553" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15404" PostTypeId="1" CreationDate="2018-10-21T16:45:37.520" Score="2" ViewCount="646" Body="&lt;p&gt;I recently have calculated the total cost of an energy system that is based on wind power as the primary power source and hydrogen as the energy storage mechanism. The total system costs are approximately similar to a system based only on new nuclear power plants built according to current regulations in the current market conditions. All of this is somewhat roughly estimated, as we don't know how much electrolyzers, hydrogen storage solutions, and hydrogen to electricity conversion in turbines or fuel cells costs in very large scales.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, hydrogen needs to be stored somewhere. Its energy density by weight is extremely high, but energy density by volume is very low, even when compressed or liquefied. There are several solutions:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Liquid hydrogen. Unfortunately, the energy efficiency of liquid hydrogen is low. Also, even with thermally isolated containers, the hydrogen needs to gradually leak away.&lt;/li&gt;&#xA;&lt;li&gt;Compressed hydrogen stored in pipelines. Unfortunately, hydrogen causes embrittlement of steel, possibly leading to hydrogen leaks.&lt;/li&gt;&#xA;&lt;li&gt;Storage in old mines, old depleted oil/gas fields, etc. However, hydrogen could theoretically leak.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;All of these solutions have the possibility that hydrogen will leak away.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, my questions are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;What are the environmental effects of hydrogen leaked to the atmosphere?&lt;/li&gt;&#xA;&lt;li&gt;What is the atmospheric lifetime of hydrogen?&lt;/li&gt;&#xA;&lt;li&gt;What is the global warming potential of hydrogen on timescales that matter (let's say 20 years or 100 years)?&lt;/li&gt;&#xA;&lt;li&gt;What is the mechanism of removal from the atmosphere? Oxidation to water, or similar to helium: escaping to space?&lt;/li&gt;&#xA;&lt;li&gt;Is the usage of hydrogen as an energy storage mechanism even justified based on the environmental effects, or are the effects so bad that it makes sense to continue burning of fossil fuels or reconsider nuclear energy?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="14108" LastEditorUserId="2470" LastEditDate="2018-10-21T17:01:47.257" LastActivityDate="2018-10-21T17:01:47.257" Title="What are the environmental effects of leaking hydrogen from large-scale energy storage mechanisms?" Tags="|atmosphere|climate-change|technology|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15406" PostTypeId="1" CreationDate="2018-10-21T21:50:41.737" Score="2" ViewCount="328" Body="&lt;p&gt;So I am wondering how much carbon any given coral can sequester given that carbon dioxide dissolves in water and forms carbonic acid, and coral uses that carbonic acid in their own calcification process given by this equation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\ce{Ca^{2+} +2HCO3- -&amp;gt; CaCO3 + H2O + CO2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given the amount of concentration of carbon dioxide that is in the atmosphere currently, how much net carbon can one coral organism sequester per year?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just as a note, I am not talking about coral reefs as a whole, but just &lt;em&gt;one&lt;/em&gt; coral organism. Obviously a lot of assumptions must be made, so please just include them in your answer please. Thank you!&lt;/p&gt;&#xA;" OwnerUserId="14113" LastActivityDate="2018-10-23T18:00:15.250" Title="How much net carbon can coral sequester?" Tags="|climate-change|oceanography|biogeochemistry|carbon-cycle|carbon|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15408" PostTypeId="1" CreationDate="2018-10-22T05:56:54.910" Score="3" ViewCount="186" Body="&lt;p&gt;I've been looking into diamonds recently and was made aware of diamond hybrids where diamond is grown on either a seed diamond or cubic zirconia. I was wondering if it would be possible to do something similar with sapphire. Sapphire core surrounded by diamond might be pretty cool...&lt;/p&gt;&#xA;" OwnerUserId="14118" LastActivityDate="2018-10-23T05:03:54.887" Title="Is it possible to form a diamond-sapphire hybrid?" Tags="|geochemistry|diamond|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15409" PostTypeId="2" ParentId="15408" CreationDate="2018-10-22T07:28:07.280" Score="4" Body="&lt;p&gt;Sapphires and ruby's are both aluminium oxide. sapphire melts at 2000 degrees and diamond synthesis can happen at 600 degrees. To coat around the sapphire, you would have to use multiple diamond seeds, which would make a polycrystal. it's probably humanly acheivable. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The scientists would have to study the adhesion of a transition layer, because the sapphire is trigonal, and makes 6 sided crystals, whereas the diamond is cubic. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/uXYRN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uXYRN.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They do use vapor deposition already to dope crystals with very colorful metals, for example you can build a home kit for titanium quartz. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Perhaps if they used some kind of force to grow the diamond in a given direction, like a carbon-cannon in the vapor chamber, they can control the diamond and have one structure around the other mineral. &lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2018-10-23T05:03:54.887" LastActivityDate="2018-10-23T05:03:54.887" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15410" PostTypeId="2" ParentId="15406" CreationDate="2018-10-22T07:40:45.867" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DPWIw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DPWIw.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Corals usually grow 1cm every year, some as slow as 2mm, some faster. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Coral sand density is about 1.5g /cm2, it's not the best estimate of coral weight. So, a coral organism of 10cm^2 produces 150 grams of CaCO3 every year, and 1m2 of coral can absorb 15 kilos.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;CO2 is 44.01 g/mol &#xA;CaCO3 is 100.0869 g/mol&lt;/p&gt;&#xA;&#xA;&lt;p&gt;15kg * .44 is the absorbtion of CO2 of a coral organism of 1m2 surface area. &#xA;that's 6.6kg. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A car produces about 6 tons of CO2 every year. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Coral reefs are estimated to cover 284,300 km2 (109,800 sq mi), just under 0.1% of the oceans' surface area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are 1 billion cars, and 9 billion tons of antropogenic CO2. &lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2018-10-23T18:00:15.250" LastActivityDate="2018-10-23T18:00:15.250" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15411" PostTypeId="2" ParentId="8385" CreationDate="2018-10-22T08:03:45.330" Score="0" Body="&lt;p&gt;I wish to provide a counterbalance argument.&#xA;it's just not wavy, it's a chaos of pressure-fronts, wind is doughnuts, and waves have equilibrium points and transmission media.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/54mQx.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/54mQx.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/U41mS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/U41mS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;vs&#xA;&lt;a href=&quot;https://i.stack.imgur.com/14jzR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/14jzR.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/vBCwa.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vBCwa.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;Scientific litterature doesn't use the word wave to describe squalls and pressure fronts, and clouds also illustrate the general behaviour of wind. Atmospheric stratification can generate 2D boundary wave clouds which form on stratospheric 2D pressure and temperature boundaries, and on oil-water boundaries: &lt;a href=&quot;https://en.wikipedia.org/wiki/Wave_cloud&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Wave_cloud&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/SPx8v.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SPx8v.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wind follows laws of turbulence and chaotic flow displacement, whereas waves travel backwards and forwards on an equilibrium point. Waves are energy displacement with a radial wave front, whereas squalls are not radial. When we look at clouds, generally there's no wave distributions visible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To view what a squall does, it's best to consider what smoke does. The smoke doesn't displace air using the elasticity of air, like a sound wave, it actively flows and generates a pressure front which displaces air sideways as much as forwards, it's quite a complex effect which is not totally like waves. &lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2018-10-24T03:50:11.697" LastActivityDate="2018-10-24T03:50:11.697" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="15412" PostTypeId="2" ParentId="11905" CreationDate="2018-10-22T10:17:05.840" Score="2" Body="&lt;p&gt;The key point here is that both theoretical models quoted - IGRF or WMM - are of the field from the Earth's core only, and only the largest scale parts of it at that. Only the WMM provides an error estimate with these values (as described above), and that error is a combination of &quot;commission errors&quot; from the approximation of the model to reality, and &quot;omission errors&quot; from various magnetic field sources which are not included in the model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To calculate a magnetic anomaly (usually considered the field from the Earth's crust) you would remove all the other known field sources from the observed field:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;anomaly field = observed field - (core field + external fields)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="14123" LastActivityDate="2018-10-22T10:17:05.840" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15413" PostTypeId="1" AcceptedAnswerId="15414" CreationDate="2018-10-22T13:53:54.837" Score="1" ViewCount="176" Body="&lt;p&gt;From 17-Oct-2018 NASA ICE &lt;a href=&quot;https://twitter.com/NASA_ICE/status/1052601381712887809&quot; rel=&quot;nofollow noreferrer&quot;&gt;tweet&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm curious of the actual dimensions, and if possible a complete photo. And curious in a scifi sort of way if they have a ratio of &lt;a href=&quot;https://en.wikipedia.org/wiki/Monolith_(Space_Odyssey)&quot; rel=&quot;nofollow noreferrer&quot;&gt;1:4:9&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;From yesterday's #IceBridge flight: A tabular iceberg can be seen on the right, floating among sea ice just off of the Larsen C ice shelf. The iceberg's sharp angles and flat surface indicate that it probably recently calved from the ice shelf.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0dWOh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0dWOh.jpg&quot; alt=&quot;NASA ICE tabular iceburg from Larsen C&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;from a following &lt;a href=&quot;https://twitter.com/pantagrapher/status/1052601813906743296&quot; rel=&quot;nofollow noreferrer&quot;&gt;tweet&lt;/a&gt; (for clarification):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yMA1e.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yMA1e.jpg&quot; alt=&quot;2001 Space Odyssey monolith&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2018-10-22T14:06:11.547" LastActivityDate="2018-10-25T06:32:36.827" Title="What are the approximate dimension of this iceberg? Any chance the ratio is 1:4:9?" Tags="|sea-ice|ice-shelf|nasa|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15414" PostTypeId="2" ParentId="15413" CreationDate="2018-10-22T15:17:53.803" Score="5" Body="&lt;p&gt;There have been rectangular tabular icebergs in the past so this is not uncommon at all. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.livescience.com/63875-weird-square-iceberg-antarctica.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kelly Brunt, an ice scientist with NASA and the University of Maryland said:&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Tabular icebergs form, she said, through a process that's a bit like a fingernail growing too long and cracking off at the end. They're often rectangular and geometric as a result&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;What makes this one a bit unusual is that it looks almost like a square,&quot; &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So I think we can categorically state that the coordinates in the plane of the sea are not 1:4 or 1:9 or even 4:9&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And we also know that underwater there will be a good 90% of its mass so it's going to be closer to a cube than the famous monolith from 2001.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A better photo, showing the whole berg shows just how non-rectangular it actually is at :&#xA;&lt;a href=&quot;https://bobcat.grahamdigital.com/30b1f2f70fffbc15f96f9b08712619ca2fd656e8/crop-640x360-000.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://bobcat.grahamdigital.com/30b1f2f70fffbc15f96f9b08712619ca2fd656e8/crop-640x360-000.jpg&lt;/a&gt;&lt;img src=&quot;https://i.stack.imgur.com/AK0wf.jpg&quot; alt=&quot;enter image description here&quot;&gt;]&lt;a href=&quot;https://i.stack.imgur.com/AK0wf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A google search for rectangular tabular icebergs returns a few beautiful examples over the last few years. There is a nice photo by &lt;a href=&quot;https://fineartamerica.com/featured/3-tabular-iceberg-antarctica-carole-anne-fooks.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Carole-Anne Fooks here&lt;/a&gt;, and I really like this one from &lt;a href=&quot;http://icestories.exploratorium.edu/dispatches/a-world-of-ice-in-pictures/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;icestories.exploratorium.edu&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UBmDX.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UBmDX.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="755" LastEditorUserId="755" LastEditDate="2018-10-25T06:32:36.827" LastActivityDate="2018-10-25T06:32:36.827" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15415" PostTypeId="2" ParentId="15413" CreationDate="2018-10-22T15:18:09.937" Score="7" Body="&lt;p&gt;Not likely.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quoting Kelly Brunt, an ice scientist with NASA and at the University of Maryland, from &lt;a href=&quot;https://www.livescience.com/63875-weird-square-iceberg-antarctica.html?utm_source=twitter&amp;amp;utm_medium=social&quot; rel=&quot;noreferrer&quot;&gt;What the Heck Is the Deal with This Weird, Square Iceberg?&lt;/a&gt; at LiveScience.com:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What makes this one a bit unusual is that it looks almost like a square,&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;which does not rhyme with anything in your suggested 1:4:9 ratio.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The article mentions the obvious&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;And, as with all icebergs, the part visible above the surface is just the top 10 percent of its mass. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;but that only tells you that 90% is under water, nothing about its absolute height above sea level. &lt;/p&gt;&#xA;" OwnerUserId="595" LastActivityDate="2018-10-22T15:18:09.937" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15418" PostTypeId="1" CreationDate="2018-10-23T04:59:47.310" Score="5" ViewCount="86" Body="&lt;p&gt;I just felt an earthquake at in a 6 floor building in Taipei, where I am familliar with how they have felt over the years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This one felt particularly vertical, and made me feel queezy, while most have side-to-side motion. There was a weak shake, and many seconds later the strong, &quot;queezy&quot; one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It looks like the epicenter is in less-deep water judging by the color of the water in the attached image. Would the reduced depth make it less likely for a tsunami to reach the shore somehow?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.cwb.gov.tw/V7e/earthquake/&quot; rel=&quot;noreferrer&quot;&gt;https://www.cwb.gov.tw/V7e/earthquake/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ET8DG.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ET8DG.jpg&quot; alt=&quot;Taiwan Earthquake 23-Oct-2018&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2018-10-25T23:59:17.983" Title="Would epicenters in less-deep areas of ocean tend to reduce the impact of a resulting tsunami somehow (wave &quot;breaks&quot; before getting there?)" Tags="|earthquakes|tsunami|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15419" PostTypeId="2" ParentId="15418" CreationDate="2018-10-23T08:39:29.497" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Tsunami&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tsunamis&lt;/a&gt; are created when large volumes of water are &lt;strong&gt;displaced vertically&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The predominant ways this can happen are when an earthquake of &lt;em&gt;significant magnitude&lt;/em&gt; is created at a subduction zone - one tectonic plate subducting under another tectonic plate. During such an event, part of one plate moves downwards or upwards very quickly causing the water above it to be displaced vertically.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other predominant way a tsunami can occur (seismically) is when an earthquake causes massive subsidence or slumping of material on the ocean floor - such as an underwater landslide. This can also create a significant vertical displacement of water. It is speculated this was the cause of the &lt;a href=&quot;http://temblor.net/earthquake-insights/tsunami-in-sulawesi-indonesia-triggered-by-earthquake-landslides-or-both-7825/&quot; rel=&quot;nofollow noreferrer&quot;&gt;October 2018 tsunami in Palu, Indonesia&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are meteorological causes of tsunamis but I won't address them because your question relates to seismically induced tsunamis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The epicenter of an earthquake, whether under shallow or deep water, is largely immaterial to the creation of tsunamis. What is is critical is whether the earthquake has caused sufficient water to be displaced vertically either through sea floor movements (tectonic plates) or slumping or subsidence of sea floor material.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The difference between a quake under shallow and deep waters would be the size of the tsunami - how much water has been displaced vertically, how much energy has been imparted into the water and thus how high any wave will be and the destructive energy that it has.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Humans have tried to create tsunamis but were largely unsuccessful. During World War II, in &lt;a href=&quot;https://en.wikipedia.org/wiki/Tsunami_bomb&quot; rel=&quot;nofollow noreferrer&quot;&gt;Project Seal&lt;/a&gt;, New Zealand tried experimenting with explosives in what is now Shakespear Regional Park. Likewise, the US did similar experiments during nuclear weapons testing in the Pacific Ocean - Operations Crossroads and Hardtack, at Bikini Atoll. The heat from the nuclear weapons produced a lot of steam, but not significant tsunamis.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="6298" LastEditDate="2018-10-23T21:04:08.157" LastActivityDate="2018-10-23T21:04:08.157" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15420" PostTypeId="2" ParentId="14946" CreationDate="2018-10-23T10:43:24.157" Score="2" Body="&lt;p&gt;I have never seen the term &quot;palingenetic fusion&quot; anywhere in the geological literature, but seeing that it &lt;a href=&quot;https://en.wikipedia.org/wiki/Palingenesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;means&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Palingenesis is a concept of rebirth or re-creation, used in various contexts in philosophy, theology, politics, and biology. Its meaning stems from Greek palin, meaning again, and genesis, meaning birth. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And seeing that it is used to describe granitic charnockites, I think it is safe to say it is a very obscure term for &lt;a href=&quot;https://en.wikipedia.org/wiki/Anatexis&quot; rel=&quot;nofollow noreferrer&quot;&gt;anatexis&lt;/a&gt;, a common process of granite formation by partial melting of pre-existing rock. This is most commonly used in high grade metamorphic rocks, and in the context of formation of migmatites and leucogranites.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-10-23T10:43:24.157" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15421" PostTypeId="1" CreationDate="2018-10-23T14:23:24.757" Score="1" ViewCount="104" Body="&lt;p&gt;Assume that I am sailing in a ship where I know the course of the ship &amp;amp; speed of the ship and observed wind direction &amp;amp; speed using Automatic Weather Station fitted on mast. I would like to know the formula used for calculating True Wind direction &amp;amp; speed? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have gone through this link &lt;a href=&quot;https://oic-nwreviewer.blogspot.com/2014/01/solving-for-true-wind-direction.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://oic-nwreviewer.blogspot.com/2014/01/solving-for-true-wind-direction.html&lt;/a&gt; which provide some input regarding the formula used. However, the atmospheric wind used in this example is an apparent wind and not the observed wind. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My intention is to write a small program so that True Wind is calculated faster. It appears to be little difficult as there is no proper formula available in the internet.&lt;/p&gt;&#xA;" OwnerUserId="5473" LastActivityDate="2018-10-23T14:23:24.757" Title="Find True Wind from ship course and observed wind" Tags="|wind|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15422" PostTypeId="1" AcceptedAnswerId="15424" CreationDate="2018-10-24T01:30:19.907" Score="6" ViewCount="224" Body="&lt;p&gt;This image is from the BBC Culture article &lt;a href=&quot;http://www.bbc.com/culture/story/20181017-striking-photos-of-human-scars-on-earth&quot; rel=&quot;noreferrer&quot;&gt;Striking photos of human scars on Earth&lt;/a&gt;. It is accompanied by the text and captions below.&lt;/p&gt;&#xA;&lt;p&gt;But I still don't understand what I'm looking at at all. Can someone recognize what's happening here? What are the phenomenon (artificial and natural) in play?&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Burtynsky categorises himself as an environmentalist, and has dedicated his life to bearing witness to “the indelible marks left by humankind on the geological face of our planet”. In other words, the increasingly ambitious scars and blemishes created by industry and large-scale human habitation, such as the vividly coloured layers from an ancient sea floor exposed by tunnelling machines 350m beneath Berezniki in Russia.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Caption: &amp;quot;Uralkali Potash Mine #4, Berezniki, Russia, 2017 (Credit: Edward Burtynsky, courtesy Flowers Gallery, London/Metivier Gallery, Toronto)&amp;quot; [Source][1].&lt;/p&gt;&#xA;&lt;p&gt;Click for full size.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UtlJn.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UtlJn.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Update: I found another view of this in the BBC's video &lt;a href=&quot;https://www.bbc.com/news/av/science-environment-49669971/the-photographer-capturing-mankind-s-impact-on-planet-earth&quot; rel=&quot;noreferrer&quot;&gt;The photographer capturing mankind's impact on planet Earth&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Edward Burtynsky travels the world trying to capture striking images of humanity's impact on the planet, from the fossil-like shapes left behind by drills in a Potash mine to the luminescent colours of lithium ponds.&lt;/p&gt;&#xA;&lt;p&gt;The Canadian photographic artist has spent 40 years focusing on large-scale human activities such as mining, quarrying, agriculture and deforestation - but he says he doesn't see himself as an environmentalist.&lt;/p&gt;&#xA;&lt;p&gt;His latest project, Anthropocene, is a collaboration with film-makers Jennifer Baichwal and Nicholas de Pencier, exploring the idea proposed by some scientists that a geological epoch shaped by human activity has begun.&lt;/p&gt;&#xA;&lt;p&gt;It includes a travelling exhibition, a book and feature-length documentary, which was premiered last year in Canada and goes on theatrical release in the US next week.&lt;/p&gt;&#xA;&lt;p&gt;Images: Edward Burtynsky, courtesy of Flowers Gallery, London / Nicholas Metivier Gallery, Toronto. Video by Heather Sharp and Laura Foster&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XveG6.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XveG6.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-09-21T16:42:03.100" Title="What are the phenomenon (artificial and natural) in play in this photograph &quot;350m beneath Berezniki in Russia&quot;?" Tags="|mining|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15423" PostTypeId="1" CreationDate="2018-10-24T06:50:14.443" Score="13" ViewCount="1193" Body="&lt;p&gt;&lt;a href=&quot;http://www.pnas.org/content/pnas/105/6/1786.full.pdf&quot; rel=&quot;noreferrer&quot;&gt;This article&lt;/a&gt; gives a wonderful overview of tipping point theory, where a large system can be brought into a different state by a small perturbation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UBaPi.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UBaPi.jpg&quot; alt=&quot;Bifurcation diagram&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Searching online I have found mostly articles on theoreticly based studies on tipping point theory and some speculating on the consequences that may occur due to global warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/U3s8T.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/U3s8T.png&quot; alt=&quot;Global warming tipping points&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am wondering if these tipping point theories are still all theoretical or are there any historical examples that provide as a base for these anticipated changes? For example, area the transitions between Eras and Periods also caused by tipping points or are they more gradual changes of the system because they occur on a very large timescale?&lt;/p&gt;&#xA;" OwnerUserId="13896" LastActivityDate="2020-04-27T08:15:24.450" Title="Tipping point theory, historical examples" Tags="|climate-change|earth-system|" AnswerCount="2" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="15424" PostTypeId="2" ParentId="15422" CreationDate="2018-10-24T08:12:05.413" Score="7" Body="&lt;p&gt;As stated in the caption for the picture this is an inside view of a potash mine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mining professionals regard potash, like most coal, to be a soft rock; unlike hard rock such as most metal sulfides.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With hard rock mining, the rock is mined by drilling holes and using explosives to break up the rock. The rock is then loaded and transported out of the mine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most soft rock mines, and particularly &lt;a href=&quot;https://www.canpotex.com/our-potash/where-potash-located/how-potash-mined&quot; rel=&quot;nofollow noreferrer&quot;&gt;potash mines&lt;/a&gt;, do not use drilling and blasting as the main means of removing rock. Instead they use specialized cutting machines to cut the rock. The shapes left in the rock, in the picture are marks created by the cutting heads of such machines. Usage of such a machine can be seen at the 3:30 mark in this &lt;a href=&quot;https://www.youtube.com/watch?v=uujIepkI6Ow&quot; rel=&quot;nofollow noreferrer&quot;&gt;You Tube video&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I answered the question &lt;a href=&quot;https://engineering.stackexchange.com/questions/12129/what-would-you-call-this-mining-vehicle-ural-20r-used-in-mining&quot;&gt;What would you call this mining vehicle? (Ural-20R, used in mining)&lt;/a&gt; on SE Engineering two years ago, when someone asked about the purpose of an unusual mining machine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Such machines are typically called &lt;a href=&quot;https://www.rocktechnology.sandvik/en/products/mechanical-cutting-equipment/continuous-miners/mc350-continuous-miner/&quot; rel=&quot;nofollow noreferrer&quot;&gt;continuous miners&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2019-09-21T16:42:03.100" LastActivityDate="2019-09-21T16:42:03.100" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15427" PostTypeId="1" CreationDate="2018-10-25T00:15:24.420" Score="3" ViewCount="2246" Body="&lt;p&gt;In petroleum geology, why do we consider hydrostatic pressure and lithostatic pressure separately? &#xA;Surely the pressure at any point, whether fluid or rock, at depth is simply equal the weight of all the fluid and rock overlying it? Hence why isn't pressure for fluids and solids equal at a particular depth? &lt;/p&gt;&#xA;" OwnerUserId="14137" LastActivityDate="2021-07-09T00:10:34.940" Title="Why do we consider hydrostatic pressure and lithostatic pressure separately?" Tags="|geophysics|hydrology|petrology|groundwater|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15428" PostTypeId="2" ParentId="939" CreationDate="2018-10-25T00:49:42.610" Score="-1" Body="&lt;p&gt;There is a definite link between a weakening geo magnetic field and the climate if the geo magnetic field is weakening in sync with a weakening solar magnetic field .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why? Because a weakening geo magnetic will compound given solar effects. When the solar magnetic field weakens one effect is an increase in galactic cosmic rays entering our atmosphere and some reaching the surface of the earth. The weakening geo magnetic fieldd will compound this. This increase in galactic cosmic rays will result in an  increase in global cloud coverage and an increase in major explosive volcanic activity and geological activity in general which will result in a cooling climate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Evidence of this is already taken place with earth quake activity on the rise and global temperatures trending lower post year 2016.&lt;/p&gt;&#xA;" OwnerUserId="14138" LastActivityDate="2018-10-25T00:49:42.610" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15431" PostTypeId="2" ParentId="9891" CreationDate="2018-10-25T18:16:56.433" Score="3" Body="&lt;p&gt;There are multiple companies that provide COD sensors...&#xA;&lt;a href=&quot;https://realtechwater.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;Real Tech Inc&lt;/a&gt;, &lt;a href=&quot;https://www.lar.com/products/cod-analysis/cod-analyzer-quickcodultra.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;LAR&lt;/a&gt;, &#xA;&lt;a href=&quot;http://www.detectronic.org/products/the-orakel-system/toc-cod-sensor/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Detectronic&lt;/a&gt;, &lt;a href=&quot;https://www.endress.com/en/field-instruments-overview/liquid-analysis-product-overview/COD-analyzer-CA80COD&quot; rel=&quot;nofollow noreferrer&quot;&gt;Endress-Hauser&lt;/a&gt;, and &lt;a href=&quot;https://www.ysi.com/carbovis&quot; rel=&quot;nofollow noreferrer&quot;&gt;YSI&lt;/a&gt;...&#xA;but they all use &lt;a href=&quot;https://en.wikipedia.org/wiki/Spectrophotometry&quot; rel=&quot;nofollow noreferrer&quot;&gt;spectrophotometry&lt;/a&gt; methods.&lt;/p&gt;&#xA;" OwnerUserId="14144" LastEditorUserId="2958" LastEditDate="2019-05-27T00:53:36.783" LastActivityDate="2019-05-27T00:53:36.783" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15432" PostTypeId="2" ParentId="4289" CreationDate="2018-10-25T22:32:00.707" Score="-1" Body="&lt;p&gt;the water would reach a rim, from there it is inevitable to curve, therefore the max would be 3 kilometres due to the mass for it to be not a sheet of water, if it were to be a metre thick the water could reach 9km, if a chixclub event would occur in the pacific, even worse, a larger asteroid. maybe even reaching 10 km as it would reach the atmosphere or evaporate.&lt;/p&gt;&#xA;" OwnerUserId="14145" LastActivityDate="2018-10-25T22:32:00.707" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15434" PostTypeId="2" ParentId="15418" CreationDate="2018-10-25T23:59:17.983" Score="1" Body="&lt;p&gt;What causes Tsunamis is the energy released, not so much the water displaced.  The energy travels through the water passing from molecule to molecule of water.  Amazing stuff.  There is a vertical 'stem' of energy.  Out in the deep ocean one will not be able to even see an abnormal 'wave'.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once that energy stem encounters a shallow bottom, that is when you see a wave above the water.  As it moves into shallower waters, that stem causes a wave higher and higher.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The wave becomes visible as the bottom of the ocean pushes that 'stem' of energy upwards and out of the water.  The size of the wave at the beach is as high as that energy and material allows.  Doesn't matter if the epicenter is low or high or what happened to inject energy into the water, that energy moves through the water WITHOUT the water actually moving until the stem of that energy is pushed out of the water in shallow depths.  Then the water falls over itself and moves on shore. Wave dynamics are fascinating!  To include 'rivers' with currents along the coasts that are separated from the larger mass of the ocean.  These 'rivers' also affect the dynamics of Tsunamis.&lt;/p&gt;&#xA;" OwnerUserId="606" LastActivityDate="2018-10-25T23:59:17.983" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15435" PostTypeId="1" CreationDate="2018-10-26T00:25:18.440" Score="3" ViewCount="75" Body="&lt;p&gt;How can I find out / where can I find the length, &quot;source&quot; (beginning point), &quot;mouth&quot; (ending point) of the &lt;em&gt;California&lt;/em&gt; portion of rivers?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, it's easy to find the length, source, and mouth of the Colorado River, which runs partly through California, but I'm just interested in the California part.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;True, I can, through somewhat meticulous research, find the California beginning and ending of the Colorado River on a map, but where can I find the length?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Googling&quot; provides a plethora of info about the river as a whole, but no so much about just the California portion...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have the same question for the Klamath (partly in Oregon) and Amargosa (partly in Nevada) rivers.&lt;/p&gt;&#xA;" OwnerUserId="3166" LastEditorUserId="3166" LastEditDate="2018-10-26T01:21:42.227" LastActivityDate="2018-10-26T01:21:42.227" Title="California length, source, and mouth of rivers" Tags="|rivers|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15436" PostTypeId="1" AcceptedAnswerId="15438" CreationDate="2018-10-26T00:51:36.257" Score="2" ViewCount="212" Body="&lt;p&gt;News of the long-lived and not unusual cloud on Mars associated with 21 km tall &lt;a href=&quot;https://en.wikipedia.org/wiki/Olympus_Mons&quot; rel=&quot;nofollow noreferrer&quot;&gt;Olympus Mons&lt;/a&gt; has people commenting. &lt;a href=&quot;https://twitter.com/tanyaofmars/status/1055217464336773120&quot; rel=&quot;nofollow noreferrer&quot;&gt;This tweet&lt;/a&gt; by planetary scientist Dr. &lt;a href=&quot;http://tanyaofmars.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tanya Harrison&lt;/a&gt; says&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;I don't understand the conspiracy theory contingent that's going off re: the clouds over Arsia Mons.&lt;/p&gt;&#xA;&lt;p&gt;What possible reason would we have to hide volcanic eruptions on Mars? Heck, NASA has shared plenty of pics of &lt;strong&gt;volcanoes erupting on Io (shown here) &amp;amp; geysers on Enceladus!&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;(see the tweet for the video)&lt;/p&gt;&#xA;&lt;p&gt;Why exactly is the feature on Io called a volcano, and the feature on Enceladus called a geyser? I understand they are substantially different, but I'm asking about how the geological classification works on bodies with different materials and temperatures than those on Earth.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-10-26T02:33:13.587" Title="Why exactly is the feature on Io called a volcano, and the feature on Enceladus called a geyser?" Tags="|volcanology|geysers|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15437" PostTypeId="1" CreationDate="2018-10-26T01:53:47.340" Score="4" ViewCount="104" Body="&lt;p&gt;I came across an &lt;a href=&quot;http://tucsoncitizen.com/morgue2/2003/09/20/20997-funeral-notices/&quot; rel=&quot;nofollow noreferrer&quot;&gt;obituary&lt;/a&gt; for a distant cousin which mentions that he was a state climatologist who developed the &quot;55/3 monsoon formula.&quot; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;KANGIESER, Paul Carl, 1923 – 2003 Passed away September 15, 2003 after a long battle with cancer. Born in Topeka, lived in LA as a child. Served in the U.S. Army for four years in WWII. &lt;strong&gt;As state Climatologist of AZ he developed the 55/3 monsoon formula.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I searched Google and couldn't find any formulas related to monsoons known as the &quot;55/3 formula&quot;, but I did find &lt;a href=&quot;https://www.azfamily.com/weather/phoenix_weather_blog/monsoon-season-the-dew-point-dilemma/article_45060ef3-873f-5128-a7dd-fea3b7a545f6.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this news article&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In 2008, The National Weather Service in Phoenix decided to make a big change. For decades, the monsoon was said to have started after &lt;strong&gt;three&lt;/strong&gt; consecutive days with a dew point of &lt;strong&gt;55&lt;/strong&gt; degrees of higher.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What is the 55/3 monsoon formula?&lt;/p&gt;&#xA;" OwnerUserId="14148" LastActivityDate="2018-10-26T01:53:47.340" Title="What is the 55/3 Monsoon Formula?" Tags="|monsoon|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15438" PostTypeId="2" ParentId="15436" CreationDate="2018-10-26T02:33:13.587" Score="4" Body="&lt;p&gt;The difference between a volcano and a geyser is defined by what is being ejected.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Volcanoes eject &lt;a href=&quot;https://en.wikipedia.org/wiki/Lava&quot; rel=&quot;nofollow noreferrer&quot;&gt;lava&lt;/a&gt;, which is molten rock. Molten rock that stays underground is called magma, but when it reaches the surface, usually via a volcano, it is called lava.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A rock is composed of minerals, such as sulphides and silicates. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Volcanology_of_Io&quot; rel=&quot;nofollow noreferrer&quot;&gt;volcanoes on Io&lt;/a&gt; eject lava that is &quot;composed of various forms of elemental sulfur. The colouration of the flows was found to be similar to its various allotropes&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some volcanoes on Earth also eject elemental sulfur, such as &lt;a href=&quot;https://www.nationalgeographic.com/magazine/2018/08/explore-getting-there-sulfur-mine-volcano-mount-ijen-indonesia/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mount Ijen&lt;/a&gt; in Indonesia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Geyser&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geysers&lt;/a&gt; on Earth typically eject water or steam. But elsewhere in the solar system &lt;a href=&quot;https://en.wikipedia.org/wiki/Geyser#Cryogeysers&quot; rel=&quot;nofollow noreferrer&quot;&gt;cryogeysers&lt;/a&gt; exist; they eject &quot;volatiles, together with entrained dust or ice particles, without liquid&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On Enceladus, the geysers eject water, ice particles &quot;and smaller amounts of other components (such as carbon dioxide, nitrogen, ammonia, hydrocarbons and silicates)&quot;. Unlike in lava from volcanoes, the silicates ejected from geysers on Enceladus are a minor component of the ejected material.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to volcanoes and geysers, there are &lt;a href=&quot;https://en.wikipedia.org/wiki/Cryovolcano&quot; rel=&quot;nofollow noreferrer&quot;&gt;cryovolcanoes&lt;/a&gt;, also known as ice volcanoes, on some bodies in the solar system. Like geysers, they eject volatiles &quot;such as water, ammonia or methane, instead of molten rock. Collectively referred to as cryomagma, cryolava or ice-volcanic melt, these substances are usually liquids and can form plumes, but can also be in vapour form. After eruption, cryomagma is expected to condense to a solid form when exposed to the very low surrounding temperature.&quot;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-10-26T02:33:13.587" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15439" PostTypeId="1" AcceptedAnswerId="15481" CreationDate="2018-10-26T23:38:47.117" Score="1" ViewCount="160" Body="&lt;p&gt;I have a 4 band image (Blue, Green, Red and Near Infrared). If I display my image with only the green band in the RGB channel, the image displayed is panchromatic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is that?&lt;/p&gt;&#xA;" OwnerUserId="14152" LastEditorUserId="6298" LastEditDate="2018-10-27T04:29:22.333" LastActivityDate="2018-11-01T19:07:06.463" Title="Satellite image displaying as panchromatic" Tags="|remote-sensing|satellites|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15442" PostTypeId="2" ParentId="15400" CreationDate="2018-10-27T11:59:46.970" Score="6" Body="&lt;p&gt;We call this the &lt;a href=&quot;https://en.wikipedia.org/wiki/Airborne_fraction&quot; rel=&quot;noreferrer&quot;&gt;airborne fraction&lt;/a&gt;, although as the name suggests, it's normally expressed as a fraction rather than a percentage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.biogeosciences.net/11/3453/2014/&quot; rel=&quot;noreferrer&quot;&gt;Raupach et al (2014)&lt;/a&gt; is an (open access) example of it being used in the literature, and in that paper they quote a long-term 1959 to 2012 value of 0.44, so in the same ball-park as your estimate.  Similarly, here's an example of it's use in &lt;a href=&quot;https://ipcc.ch/publications_and_data/ar4/wg1/en/ch7s7-3-5-2.html&quot; rel=&quot;noreferrer&quot;&gt;Chapter 7 of the IPCC AR4&lt;/a&gt; with a range of modelled values from 0.4 to 0.5.  It's also often calculated over single years, as in your example, to look at the trends and variability.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an aside, the 2 ppm in your calculation is called the &lt;a href=&quot;https://www.newscientist.com/article/2112153-a-pause-in-growth-rate-of-atmospheric-co2-is-over-heres-why/&quot; rel=&quot;noreferrer&quot;&gt;atmospheric CO2 growth rate&lt;/a&gt; and the total mass of CO2 in the atmosphere would be the atmospheric CO2 &lt;em&gt;burden&lt;/em&gt;.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2018-10-27T11:59:46.970" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15443" PostTypeId="2" ParentId="12685" CreationDate="2018-10-27T19:00:33.060" Score="2" Body="&lt;p&gt;All the new energy added to the earth’s environment comes from outside our planet.  The sun is the biggest contributor, then other factors like meteors, radiation from other energy sources in our galaxy, etc.  All of the sun’s energy hitting the earth either reflects back out into space or is temporarily absorbed by other masses (water, rocks, air, plants, animals) as heat and then radiated back out.  Most of the heat eventually radiates back out into space, but some gets reflected back down to earth by the CO2 and other substances in our atmosphere. More CO2 = more heat energy being reflected back down to earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When humans and other animals and bacteria consume plant and animal matter, we are consuming the energy from the sun that was used to grow the plants at the bottom of the food chain. Then our bodies burn the stored chemical energy and turn it into kinetic energy and release it into the atmosphere as radiant heat energy. If a smaller human population grew less food then less of the sun’s energy would be temporarily absorbed by those crops and ultimately released back into the atmosphere as heat.  More humans growing and consuming more food would cycle more energy through that system, but ultimately there will be equilibrium between the amount of energy consumed by plants and then released back into the atmosphere by the organisms who consume those plants regardless of population size.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So NO, human body temperature itself has no direct lasting impact on the earth’s temperature. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Millions of years worth of our sun’s energy that was temporarily stored by plants in prehistoric times got locked up longer term in oil deposits underground.  Humans have been drilling and pumping that oil out of the ground and burning it to make our lives easier/better, but in the process we are releasing millions of years worth of stored energy into the atmosphere in a relatively short amount of time.  Much of that released energy radiates out into space, but some of it gets reflected back down to earth by the increasing CO2 levels in our atmosphere.  And human’s burning of fossil fuels is the biggest contributor to adding new CO2 to our atmosphere.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Atomic energy powerplants release energy as heat into the atmosphere that would eventually be released into the atmosphere on its own by the radioactive elements themselves even if humans weren’t manipulating them, but at an accelerated rate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Storing and then using renewable energy such as solar and wind (wind energy originates as the sun’s solar energy moves air around our atmosphere, plus some kinetic energy from the rotation of the earth) are net neutral to our planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The energy stored in and released from the earth’s core is another factor that we’ll save for another discussion. In the meantime, let’s all accept that our planet is warming as a result of humans releasing prehistoric energy into the atmosphere at a relatively rapid rate compared to how long it took for that energy to accumulate.  (Mic drop)&lt;/p&gt;&#xA;" OwnerUserId="14157" LastEditorUserId="14157" LastEditDate="2018-10-27T22:55:51.593" LastActivityDate="2018-10-27T22:55:51.593" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15445" PostTypeId="1" AcceptedAnswerId="15454" CreationDate="2018-10-28T00:49:28.750" Score="5" ViewCount="602" Body="&lt;p&gt;NOAA weather forecast maps often include a valid time period, e.g:  &quot;valid from time1 thru time2.&quot;  However, many maps only indicate a single time, e.g: &quot;valid time1.&quot;  In the absence of other information, does this typically (or officially) mean valid up until time1, or valid after time1?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT:&#xA;Link to &lt;a href=&quot;https://www.aviationweather.gov/data/products/turbulence/20181028/16/20181028_16_F00_gtg_170_total.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;example map&lt;/a&gt; and &lt;a href=&quot;https://www.aviationweather.gov/turbulence/gtg&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="14160" LastEditorUserId="14160" LastEditDate="2018-10-28T18:11:17.990" LastActivityDate="2018-11-26T17:30:34.670" Title="What's the default meaning of &quot;Valid&quot; in NOAA weather map?" Tags="|meteorology|national-weather-service|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15450" PostTypeId="1" AcceptedAnswerId="15451" CreationDate="2018-10-28T22:04:50.397" Score="2" ViewCount="56" Body="&lt;p&gt;I am given a 3 box model of atmosphere where each layer is 300 mbar thick, and the potential equivalent temperature of each is given (from bottom to top - 350K, 325K, 375K).  Am I able to determine the specific humidity of each layer with just this information?  I am racking by brain, trying to make this work, but I feel I need more information. &lt;/p&gt;&#xA;" OwnerUserId="13928" LastActivityDate="2018-10-28T23:01:17.613" Title="Given only pressure and potential equivalent temperature, can I determine other variables?" Tags="|atmosphere|temperature|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15451" PostTypeId="2" ParentId="15450" CreationDate="2018-10-28T23:01:17.613" Score="1" Body="&lt;p&gt;I think you cannot, might be wrong on that though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a single-fluid atmosphere without condensibles, the pressure is essentially proportional to &lt;span class=&quot;math-container&quot;&gt;$P \sim \rho \, T$&lt;/span&gt; and potential temperature is essentially &lt;span class=&quot;math-container&quot;&gt;$\theta \sim T &#xA;P^{1-1/\gamma}$&lt;/span&gt;, with the temperature &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt;, and the adiabatic index of the gas &lt;span class=&quot;math-container&quot;&gt;$\gamma$&lt;/span&gt;.&lt;br&gt;&#xA;So in this situation you could reconstruct density and temperature from &lt;span class=&quot;math-container&quot;&gt;$P$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt;, but if you add another fluid into the mix (which is your condensible), then I don't see how that should be possible.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2018-10-28T23:01:17.613" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15452" PostTypeId="1" AcceptedAnswerId="15464" CreationDate="2018-10-29T00:20:22.063" Score="3" ViewCount="60" Body="&lt;hr&gt;&#xA;&#xA;&lt;p&gt;P = 300mb, Pot. Equiv. Temp = 375K &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;P = 600mb, Pot. Equiv. Temp = 325K&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;P = 900mb, Pot. Equiv. Temp = 350K  &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;(surface)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given that a deep convective plume sends a portion of the bottom layer to the top:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What fraction of the mass of the lower layer must rise in order to just barely stabilize the lower layer with respect to the middle layer?  How many millibars of environmental subsidence does this imply?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I need direction on how to begin this.  Which equation will assist with this answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;My attempt&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I remove a chuck sized &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt; from the bottom layer, it will contain &lt;span class=&quot;math-container&quot;&gt;$\frac{3m}{2}$&lt;/span&gt; the mass of the middle layer of same size.  So, is the answer simply &lt;span class=&quot;math-container&quot;&gt;$\frac{2}{3}$&lt;/span&gt; of the mass must move out of the lower layer?  I believe I am wrong, it seems to be more involved than this, but I cannot grasp this concept.  &lt;/p&gt;&#xA;" OwnerUserId="13928" LastActivityDate="2018-10-30T01:48:49.477" Title="Given a 3 box model of the atmosphere,determine fraction of mass transport from lower layer" Tags="|atmosphere|temperature|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15454" PostTypeId="2" ParentId="15445" CreationDate="2018-10-29T07:30:25.273" Score="8" Body="&lt;p&gt;Short answer: &lt;strong&gt;Valid&lt;/strong&gt; just means the expected conditions at that certain time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In your &lt;a href=&quot;https://www.aviationweather.gov/data/products/turbulence/20181028/16/20181028_16_F00_gtg_170_total.gif&quot; rel=&quot;noreferrer&quot;&gt;example&lt;/a&gt; the map shows a forecast of 00 hours which is &lt;strong&gt;valid&lt;/strong&gt; for 0600 UTC. Basically it means that the forecast/simulation is initialized on 0600 UTC and because the forecast time is 00 hours this forecast is also &lt;strong&gt;valid&lt;/strong&gt; for 0600 UTC.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NOAA also provides forecasts for several hours (or days depending on the product). In this case, your simulation may be initialized on 0600 UTC but if you want to see what the conditions on 1500 UTC are you have a forecast of 09 hours which is &lt;strong&gt;valid&lt;/strong&gt; for 1500 UTC. See &lt;a href=&quot;https://i.stack.imgur.com/6AhJF.gif&quot; rel=&quot;noreferrer&quot;&gt;this example&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="13896" LastEditorUserId="13896" LastEditDate="2018-10-29T07:37:48.493" LastActivityDate="2018-10-29T07:37:48.493" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15455" PostTypeId="1" CreationDate="2018-10-29T07:43:52.527" Score="1" ViewCount="34" Body="&lt;p&gt;Need to create and maintain Biofloc for fish farming in India, it's really successful in Indonesia and I believe it's due to environmental conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can we replicate the same in India?&lt;/p&gt;&#xA;" OwnerUserId="14168" LastActivityDate="2018-10-29T07:43:52.527" Title="How to create Indonesian environmental conditions in India?" Tags="|meteorology|environmental-protection|regional-geology|environmental-sensors|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15456" PostTypeId="2" ParentId="14520" CreationDate="2018-10-29T07:56:55.663" Score="2" Body="&lt;p&gt;&lt;strong&gt;Short answer:&lt;/strong&gt; I think the difference in the 2 soundings can be mostly explained by moving from one air mass (low pressure, relatively humid) to another (high pressure,  relatively dry) which also increases the tropopause height.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing you have to realize is that radiosoundings never provide a perfect vertical profile moving straight into the atmosphere with respect to the location you start your radiosounding but rather move with the wind. One thing that is obvious from your radiosoundings is that there is a strong backing of the wind, visible in the layer from the surface up to 500 hPa but most prominent in the layer from the surface up to +/- 700 hPa. Also, the wind speed seems to decrease slightly. These conditions imply that your location of the radiosounding near the height of the tropopause (may) have shifted significantly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In combination with the temporal difference of 12 hours this may explain the discrepancy. From the first sounding to the second we also see advection of relatively warm, dry air in the 800-400 hPa layer. We find that temperatures go up, and the differnce between temperature and dry bulb temperature seems to increase. We also find that the surface pressure goes up, indicating a regime with higher pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Still, we can not be certain that these conditions specifically apply for your radiosounding location. We can conclude that the above findings are speficially true for the &lt;em&gt;pathway of the radiosonde&lt;/em&gt;.&lt;/p&gt;&#xA;" OwnerUserId="13896" LastEditorUserId="13896" LastEditDate="2018-10-29T13:20:26.437" LastActivityDate="2018-10-29T13:20:26.437" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15457" PostTypeId="1" CreationDate="2018-10-29T10:13:40.960" Score="7" ViewCount="116" Body="&lt;p&gt;The rainfall leaches salts (Mg,Na,Ca,K,.., Cl) from weathering rocks, where those ions were freed from chemical bonds by sunlight, acidic water etc. The runoff eventually goes into the oceans, where evaporation of water leads to accumulation of salts. Over geological timeframes the oceans fall dry and the salts deposit as huge layers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question: Is there a net accumulation of salts, or do subduction or other effects reintroduce these ions into mineralic (and non-salt) chemical bonds? -my question is about whether this is a primarily one-way street from minerals to salts, or whether the salts get 'recycled' by, e.g. being subducted and then re-bound in the heat of the mantle.&lt;/p&gt;&#xA;" OwnerUserId="12789" LastEditorUserId="12789" LastEditDate="2018-10-29T14:20:02.393" LastActivityDate="2018-11-10T02:55:18.133" Title="Is salt accumulating over time?" Tags="|water|crust|salinity|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15458" PostTypeId="2" ParentId="15457" CreationDate="2018-10-29T14:03:02.810" Score="4" Body="&lt;p&gt;There is a limit to how much of a given salt can be dissolved into water, this is known as it's &lt;a href=&quot;https://en.wikipedia.org/wiki/Solubility&quot; rel=&quot;nofollow noreferrer&quot;&gt;solubility&lt;/a&gt; and it's dynamic based upon how much of any particular &lt;a href=&quot;https://en.wikipedia.org/wiki/Ion&quot; rel=&quot;nofollow noreferrer&quot;&gt;ion&lt;/a&gt; is already present. Once concentrations exceed the local solubility of a given compound precipitation occurs, this can be seen in the modern Mediterranean basin with the precipitation of &lt;a href=&quot;https://en.wikipedia.org/wiki/Calcium_carbonate&quot; rel=&quot;nofollow noreferrer&quot;&gt;calcium carbonate&lt;/a&gt; onto the seabed. There are also older examples of this response such as chemically precipitated chert in New Zealand.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's one way in which dissolved chemicals can be re-integrated into the rock cycle, biological processes can also play an important role. Plankton take up many elements from sea water during their life cycle, notably silica and calcite for forming rigid structures these are then deposited in the deep ocean when they and the creatures that predate them die and form the basis for many sedimentary rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So while there is a steady input of mineral salts into the ocean there's only so much of it that can accumulate and in fact a lot of them are removed at far lower concentrations due to biological use and subsequent deposition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A measure of any deposited material may eventually be subducted with the oceanic crust on which it has settled, at which point it will be integrated into any subductive-melt sourced minerals. There is a trend towards the chemical depletion  of the mantle when it comes to certain elements which appears to be a one way street but the ocean does eventually give back a large percentage of what is dissolved into it.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="10735" LastEditDate="2018-10-29T14:27:28.527" LastActivityDate="2018-10-29T14:27:28.527" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="15460" PostTypeId="1" CreationDate="2018-10-29T16:25:32.993" Score="1" ViewCount="9252" Body="&lt;p&gt;It could be sedimantary or metamorphic rock or intrusive igneous rock&lt;/p&gt;&#xA;" OwnerUserId="14171" LastActivityDate="2018-10-30T15:25:09.527" Title="What type of rock formed first on earth and which rock is the oldest?" Tags="|planetology|" AnswerCount="1" CommentCount="2" ClosedDate="2018-10-30T15:26:32.450" ContentLicense="CC BY-SA 4.0" />
  <row Id="15461" PostTypeId="2" ParentId="12100" CreationDate="2018-10-29T16:26:30.650" Score="3" Body="&lt;p&gt;Regions where the strength of the horizontal component (H) of the magnetic field is small (i.e. where the field is close to vertical near the magnetic poles) define where a compass won't work reliably.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example where H drops below 5000nT is considered unreliable for values of magnetic declination as per the error calculations in &lt;a href=&quot;http://www.geomag.bgs.ac.uk/documents/WMM2015_Report.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;the World Magnetic Model 2015 report&lt;/a&gt;. I've seen aviation charts (of which I can't find an example) where 6000nT (also based on the WMM as that's the industry standard there too) is used to define where another navigation aid should be take preference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can get an idea of the geographic distances involved from &lt;a href=&quot;http://www.geomag.bgs.ac.uk/images/charts/jpg/polar_n_h.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;this map&lt;/a&gt; of the 2015 horizontal field intensity over the northern hemisphere. The distance of a given field strength value to the pole isn't a fixed value as the field isn't exactly a dipole, so the &lt;a href=&quot;http://www.geomag.bgs.ac.uk/images/charts/jpg/polar_s_h.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;south pole map&lt;/a&gt; looks quite different, but you get a realistic idea at least. Something like within 2,500km in the North, and a few hundred km in the South.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As @Tactopoda pointed out, declination can be very large within thousands of km of a magnetic pole, and &lt;a href=&quot;http://www.geomag.bgs.ac.uk/images/charts/jpg/polar_n_dh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;the annual rate of change of H&lt;/a&gt; is also much greater than elsewhere, hence why a compass isn't very reliable, even where it can give a consistent reading.&lt;/p&gt;&#xA;" OwnerUserId="14123" LastActivityDate="2018-10-29T16:26:30.650" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15462" PostTypeId="1" CreationDate="2018-10-29T17:49:13.867" Score="5" ViewCount="348" Body="&lt;p&gt;About a year ago, I took this video along the Hudson river in NY, and I'm trying to figure out the Beaufort number based on the water and the flags.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=nqjvTALRWW8&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=nqjvTALRWW8&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem is that the Beaufort scale is based primarily on open sea waters (not protected/inland waters like the Hudson river).  The only mention in the scale relating to inland waters is force 5 (&quot;crested wavelets (whitecaps) form on inland waters&quot;) - but nothing related to the higher force numbers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this video, there are definitely lots of whitecaps, which leads me to believe that the wind was force 5 or higher.  Possibly even a 6.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Flags are another indicator; but here it is kind of vague.  At force 5, flags start rippling and flapping hard, and as the wind gets stronger, they start beating/snapping, until finally they are fully extended with only the very end flapping (force 7).  So looking at the flag in the video makes me think it's a 6.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What steady force/speed is the wind really blowing here?  What about gusts?&lt;/p&gt;&#xA;" OwnerUserId="14173" LastEditorUserId="595" LastEditDate="2018-10-29T21:49:18.833" LastActivityDate="2018-10-31T19:00:57.127" Title="Judging wind speed based on flags and inland-water observations" Tags="|meteorology|water|wind|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15463" PostTypeId="2" ParentId="15462" CreationDate="2018-10-29T20:50:09.460" Score="4" Body="&lt;p&gt;I would call that about a force 3. But be aware that one of the problems near shore is that the shoreline, buildings, and topography have a large effect on the local winds - both direction and speed. Also fetch makes a difference - waves don't have enough time/space to build to their full size without sufficient fetch. Not the case in your video but it is difficult to evaluate waves when looking downwind because you see the less-steep backs of the waves and maybe only the tips of the whitecaps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sea kayakers have some decent resources for estimating winds near-shore because most kayakers spend the majority of their time in that environment. &lt;a href=&quot;http://www.kayarchy.com/html/03thesea/003wind.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here is one example&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2018-10-29T20:50:09.460" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15464" PostTypeId="2" ParentId="15452" CreationDate="2018-10-30T01:48:49.477" Score="1" Body="&lt;p&gt;&lt;strong&gt;My results:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If an &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt; sized chunk was moved up, then what remains is &lt;span class=&quot;math-container&quot;&gt;$(1-\alpha)$&lt;/span&gt;.  Because each layer is 300mb thick, they have equal parts mass.  What goes up must be compensated, and due to conservation of mass, there is no gain or loss of mass in my system.  Potential temperature is a conserved quantity, so I can say:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$350K(1-\alpha)+325K\alpha = 325K(1-\alpha)+375K\alpha$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\alpha = \frac{1}{3}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further,&#xA;&lt;span class=&quot;math-container&quot;&gt;$\frac{1}{3}$&lt;/span&gt; mass movements equates to &lt;span class=&quot;math-container&quot;&gt;$\frac{1}{3}$&lt;/span&gt; of a &lt;span class=&quot;math-container&quot;&gt;$300mb$&lt;/span&gt; layer, which is &lt;span class=&quot;math-container&quot;&gt;$100mb$&lt;/span&gt; subsidence. &lt;/p&gt;&#xA;" OwnerUserId="13928" LastActivityDate="2018-10-30T01:48:49.477" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="15466" PostTypeId="2" ParentId="15460" CreationDate="2018-10-30T15:25:09.527" Score="1" Body="&lt;p&gt;Does look a bit like a homework question..&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;First rock&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Igneous rocks would have formed first, obviously, although if we consider the pre-Mars-forming collision Earth, then the process of cold accretion could have initially formed metamorphic rocks at the center of the early &lt;a href=&quot;https://www.universetoday.com/37116/planetoid/&quot; rel=&quot;nofollow noreferrer&quot;&gt;planetoid&lt;/a&gt;..&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And that planetoid would have to be considered sedimentary, formed out of dust particles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what the first rock is depends on how you define Earth, or the point at which a specific planetoid would be positively identified as Earth.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Oldest Rock&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;First, are we talking about the oldest identifiable mineral grain (&lt;a href=&quot;https://www.livescience.com/43584-earth-oldest-rock-jack-hills-zircon.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zircons, about 4.4 billion years old&lt;/a&gt;), or the oldest complete rock (&lt;a href=&quot;https://en.wikipedia.org/wiki/Isua_Greenstone_Belt&quot; rel=&quot;nofollow noreferrer&quot;&gt;Isua Greenstone Belt, Greenland&lt;/a&gt;, 3.8 billion years). The first may qualify as part of a sedimentary rock, the second is metamorphic - but with a volcanic original rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And, of course, there could well be a meteorite out there - yet to be discovered or dated - that originates from &lt;a href=&quot;http://www.sciencemag.org/news/2018/03/mysterious-asteroid-visited-us-beyond-our-solar-system-probably-came-place-two-stars&quot; rel=&quot;nofollow noreferrer&quot;&gt;outside the solar system&lt;/a&gt; and is therefore older than the solar system. That would qualify as the oldest rock on the planet.&lt;/p&gt;&#xA;" OwnerUserId="8217" LastActivityDate="2018-10-30T15:25:09.527" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15468" PostTypeId="1" CreationDate="2018-10-31T03:36:05.860" Score="0" ViewCount="146" Body="&lt;p&gt;I found these rocks in my pasture and was excited because I thought I had found some geodes.  The rocks were in a sandy bank and looked like eggs sticking out of the bank.  I am located in Ness County Kansas.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/gjOLz.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gjOLz.jpg&quot; alt=&quot;rough rock&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is what they looked like after I opened them.  There are no crystals but some had a round ball in  the center.  Others were just empty centers.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/coSNr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/coSNr.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14181" LastActivityDate="2018-10-31T17:11:01.880" Title="I need help with these geode like rocks" Tags="|rocks|minerals|fossils|crystals|geodesy|" AnswerCount="1" CommentCount="3" ClosedDate="2018-11-02T12:30:50.173" ContentLicense="CC BY-SA 4.0" />
  <row Id="15470" PostTypeId="2" ParentId="15423" CreationDate="2018-10-31T11:42:40.810" Score="0" Body="&lt;p&gt;There is probably more up to date information, but have a look at this&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.clim-past.net/6/77/2010/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Livina et. al. Potential analysis reveals changing number of climate states during the last 60 kyr &lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;for a study showing that abrupt glacial climate change may have been associated with multiple equilibria (and a method to detect transitions between them).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/ncomms6752&quot; rel=&quot;nofollow noreferrer&quot;&gt;Boulton et.al. Early warning signals of Atlantic Meridional Overturning Circulation collapse in a fully coupled climate model&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;paper is of interest too.&lt;/p&gt;&#xA;" OwnerUserId="13736" LastEditorDisplayName="user20217" LastEditDate="2020-04-27T08:15:24.450" LastActivityDate="2020-04-27T08:15:24.450" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15471" PostTypeId="2" ParentId="15468" CreationDate="2018-10-31T15:27:49.880" Score="1" Body="&lt;p&gt;Hi:  Your rocks are not geodes but likely concretions.  The wiki article even mentions concretions from Kansas though the concretions described don't to me fit what I see in the images.  Better pictures and more description about the rocks would lead to better identification.  See &lt;a href=&quot;https://earthscience.meta.stackexchange.com/questions/124/a-guide-for-asking-identify-this-rock-questions&quot;&gt;Better rock ID requests&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Concretion&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wiki's Concretion Page&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastEditorUserId="1199" LastEditDate="2018-10-31T17:11:01.880" LastActivityDate="2018-10-31T17:11:01.880" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15475" PostTypeId="1" AcceptedAnswerId="15485" CreationDate="2018-10-31T23:52:48.420" Score="9" ViewCount="292" Body="&lt;p&gt;If I understand this correctly, Venice was &lt;em&gt;not&lt;/em&gt; flooded due to sudden rainfall causing rivers to overflow, but due to the &lt;strong&gt;high tides&lt;/strong&gt;. These high tides were caused by an alignment of sun, which was expanding the waters of the oceans disproportionately on one hemisphere and moon, which shifted the center of gravity of the moon-earth system in such a way that water rose on the same hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the news articles that I see, they also mention &lt;strong&gt;strong winds&lt;/strong&gt;. This would make sense. High baseline + waves = a lot of water in the city. But in these photos everything seems to be calm. No waves, no wind, just an abnormally high level of water:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.theatlantic.com/photo/2018/10/venice-under-water/574396/?fbclid=IwAR1DWLs_W39ndpdLWLZ1f6wlDDw8ZJmcBqyVM555O9DL5a_DhuY0mPQDi38&quot; rel=&quot;noreferrer&quot;&gt;https://www.theatlantic.com/photo/2018/10/venice-under-water/574396/?fbclid=IwAR1DWLs_W39ndpdLWLZ1f6wlDDw8ZJmcBqyVM555O9DL5a_DhuY0mPQDi38&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For me this doesn't make any sense. If the winds subsided and the flooding was caused &lt;strong&gt;purely by tidal effects, which are astronomical events&lt;/strong&gt;, shouldn't it have been predictable months, if not years in advance?&lt;/p&gt;&#xA;" OwnerUserId="7522" LastActivityDate="2018-11-01T23:29:55.583" Title="How was Venice flooded?" Tags="|sea-level|tides|seasons|flooding|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15476" PostTypeId="1" CreationDate="2018-10-31T23:56:38.397" Score="5" ViewCount="195" Body="&lt;p&gt;I am an engineering student at Alfred University and some fellow classmates and I are doing a competition, but one of the tasks we need to complete is autonomously measuring the composition, density, and hardness of layers of overburden. I was thinking that using acoustics would be possible to accomplish these things. What follows is exactly what we have to do:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;2.Create a digital core that contains the following information: The number of overburden layers in their test station&#xA;A sequence of the layers in order from softness to hardest&#xA;The thickness of each layer&#xA;The digital core should result from information garnered using system telemetry and not via placing a ruler down the hole. Teams may not touch the layers to determine hardness.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reading has to be continuous. For example another way we could do this is measure the resistance on our auger as it tries to dig a hole. This would provide a continuous reading, but might not be accurate because our frame holding the auger may not be solid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question is &quot;can we use sound waves to measure the composition, density, and hardness of each layer?&quot; The total overburden depth will be between 0.5 and 0.8 m. I don't know if this is a large enough volume to measure all of these things using sound waves. &lt;/p&gt;&#xA;" OwnerUserId="14191" LastEditorUserId="2470" LastEditDate="2018-11-01T01:57:52.763" LastActivityDate="2018-11-02T14:49:58.740" Title="Using acoustics to measure the composition, density, and hardness of layers" Tags="|geology|seismology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15478" PostTypeId="2" ParentId="15475" CreationDate="2018-11-01T14:36:41.013" Score="5" Body="&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Venice can't really be flooded by rivers, since there are none worth mentioning throughout the city.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;High tides are predictable, yes.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Take a look at how Venice is &lt;a href=&quot;https://www.google.de/maps/@45.4288411,12.3728455,12.5z&quot; rel=&quot;noreferrer&quot;&gt;situated&lt;/a&gt;. The historic city is sheltered behind low sandbanks/islands, which form the foremost coastline. Still the laguna is - obviously - connected to the open sea. Meaning: Huge waves, like in the open sea, wont rush through the city's channels, since they are dispersed by these islands. Still, in some images the water is quite choppy - a sign for rather windy conditions. Furthermore, all the houses of the city act like additional &quot;islands&quot;, calming the surface of the water by dispersing larger waves into smaller and smaller ones. However, wind does not only create waves, it pushes the water also into the direction it is blowing to. In case of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Sirocco&quot; rel=&quot;noreferrer&quot;&gt;Scirocco&lt;/a&gt;, which blows from northern Africa across the Mediterranean right into the Adriatic Sea, at which northern end Venice is situated. Thus, this wasn't simply a high tide, it was a spring tide, a combination of favourable planetary alignment and wind conditions. And, as already commented, winds/weather are quite hard to predict.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The whole process actually has a local name: &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Acqua_alta&quot; rel=&quot;noreferrer&quot;&gt;Acqua alta&lt;/a&gt;&quot;. It is nothing new, simply the intensity was noteworthy.&lt;/p&gt;&#xA;" OwnerUserId="14194" LastActivityDate="2018-11-01T14:36:41.013" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15480" PostTypeId="1" AcceptedAnswerId="15483" CreationDate="2018-11-01T17:36:52.477" Score="6" ViewCount="178" Body="&lt;p&gt;I am wondering what field studies &quot;minerals&quot;, such as the &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_minerals&quot; rel=&quot;noreferrer&quot;&gt;minerals in Wikipedia's list&lt;/a&gt;. I keep thinking that perhaps it would be covered in inorganic chemistry (&lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_inorganic_compounds&quot; rel=&quot;noreferrer&quot;&gt;list of inorganic compounds wiki&lt;/a&gt;), but for example the mineral &quot;Abelsonite&quot; is not in the inorganic list, though it does seem to have a chemical formula, C₃₁H₃₂N₄Ni. I am not sure where the boundary is between &quot;minerals&quot; and &quot;inorganic molecules&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to know so that in terms of data, if pubmed lists the data for inorganic compounds, then perhaps it also includes the data on minerals. But if the two fields are separate (mineralogy and inorganic chemistry), then perhaps the data for each is treated separately as well.&lt;/p&gt;&#xA;" OwnerUserId="784" LastActivityDate="2018-11-06T05:18:32.763" Title="If the study of &quot;minerals&quot; is covered by inorganic chemistry" Tags="|geochemistry|mineralogy|open-data|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15481" PostTypeId="2" ParentId="15439" CreationDate="2018-11-01T19:07:06.463" Score="5" Body="&lt;p&gt;An RGB image can not be rendered if you only supply information for one color channel. This is because three channels are needed: Red, Green and Blue. Different software will deal with this invalid input in different ways: Some might set the remaining channels as black (i.e. filling with zero values). In that case the resulting image will be monocromatic. In shades of green in your example.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other software might fill the missing channels with the same information supplied for the available one. In that case the result is a gray scale version of the band supplied.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a general case, the rendered image will only display varying colors if two or more channels contain different information (i.e. different bands).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As mentioned in the comments, it is important to note that the difference between monocromatic and pancromatic. The former is a general term used to describe images formed by shades of a single color. While the latter is a specific term used in multispectral sensors to denote a band with a wider spectral response, and that usually have also higher spatial resolution.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-11-01T19:07:06.463" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15483" PostTypeId="2" ParentId="15480" CreationDate="2018-11-01T21:40:16.700" Score="6" Body="&lt;p&gt;The study of minerals is the field &quot;mineralogy&quot; In some ways it would be a subset of inorganic chemistry, restricted to crystaline materials of natural origin. However, mineralogy includes the physical as well as chemical properties, especially crystallography, X-Ray diffraction and optical properties. It also includes aspects of how the minerals were formed in nature. Minerals also may be named by their chemical formula, but some chemicals have different crystal forms so two minerals can have the same formula. For example the minerals calcite and aragonite are forms of calcium carbonate, &lt;span class=&quot;math-container&quot;&gt;$\ce{CaCO_3}$&lt;/span&gt;. So you may need to broaden your search in pubmed and they may not include data for all minerals.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastEditorUserId="725" LastEditDate="2018-11-06T05:18:32.763" LastActivityDate="2018-11-06T05:18:32.763" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15485" PostTypeId="2" ParentId="15475" CreationDate="2018-11-01T23:29:55.583" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;If the winds subsided and the flooding was caused purely by tidal effects, which are astronomical events, shouldn't it have been predictable months, if not years in advance?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The tides are only partially caused by astronomical events. There's always some difference between predicted and observed tide levels. The former typically only use astronomical indicators while the latter reflect all influences. Multiple influences resulted in those exceptionally high tides in Venice on 29 October 2018.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The astronomical influences are biased toward higher than average high tides at Venice at this time of year. The reason is that annual and semiannual tidal components at Venice peak in autumn and winter. Late autumn to midwinter is when Venice historically has experienced most of its exceptionally high tide events.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Two even longer term influences are subsidence and sea level rise. These alone have made tides relative to buildings in Venice 23 cm higher than they were in 1897. Venice suffered only one exceptionally high tide event (high tides at the benchmark Punta della Salute recording site that exceed exceed 140 cm) between 1872 to 1950. In contras it has suffered ten such events in the last two decades (including the 29 October 2018 event).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The straws that broke the camel's back were a confluence of a very strong storm and the shape of the Adriatic Sea. Taken individually, neither would have caused the 29 October 2018 event. The storm was associated with strong southerly winds (winds that blow from the south) that pushed waters northward along the eastern coast of Italy. By itself, this would have resulted in a storm surge that would have raised waters in the lagoon around Venice by 10, maybe 20 centimeters. Some flooding would have resulted if the storm surge coincided with astronomical high tide, but not the exceptionally high amount that was observed. Moreover, that would have been a coincidental fluke of an event.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What those winds did instead was to make the entire Adriatic Sea slosh longitudinally (east-to-west and back). This is called a &lt;a href=&quot;https://en.wikipedia.org/wiki/Seiche&quot; rel=&quot;noreferrer&quot;&gt;seiche&lt;/a&gt;. Seiches are standing waves that occur in enclosed / semi-enclosed bodies of water. In addition to the Adriatic, seiches also occur in the Baltic (which occasionally floods St. Petersburg in a very similar manner to the flooding of Venice), the Great Lakes, and several other bodies of water. The Adriatic Sea seiche has a period of about 22 hours. The storm that preceded the 29 October 2018 flooding event lasted long enough to make the Adriatic seiche have a rather high amplitude and be rather long-lived.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The flooding occurred when the peak of this 22 hour period standing wave at Venice coincided with the peak of the short term (e.g., the 12.421 hour &lt;span class=&quot;math-container&quot;&gt;$M_2$&lt;/span&gt; tidal component) astronomical tidal influences. Adding in the long term influences (annual and semiannual astronomical tides, subsidence, and sea level rise) made the 29 October 2018 flooding event not just exceptional but nearly record-breaking.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-11-01T23:29:55.583" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15486" PostTypeId="1" AcceptedAnswerId="15488" CreationDate="2018-11-02T00:19:43.860" Score="9" ViewCount="126" Body="&lt;p&gt;The BBC News article &lt;a href=&quot;https://www.bbc.com/news/science-environment-46046067&quot; rel=&quot;noreferrer&quot;&gt;Climate change: Oceans 'soaking up more heat than estimated'&lt;/a&gt; mentions Argo floats as one technology to measure the temperature of the oceans, and links to &lt;a href=&quot;http://www.argo.ucsd.edu/&quot; rel=&quot;noreferrer&quot;&gt;argo.ucsd.edu&lt;/a&gt; where there is the map below that looks surprisingly uniform.&lt;/p&gt;&#xA;&lt;p&gt;I had thought that an initial distribution of floating objects would, over the course of years, end up clumpy and gyre-bound. Is there something that is actively managing this uniformity, or at least passively maintaining it?&lt;/p&gt;&#xA;&lt;p&gt;From the UCSD link:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;What is Argo?&lt;/p&gt;&#xA;&lt;p&gt;Argo is a global array of 3,800 free-drifting profiling floats that measures thetemperature and salinity of the upper 2000 m of the ocean.  This allows, for the first time, continuous monitoring of the temperature, salinity, and velocity of the upper ocean, with all data being relayed and made publicly available within hours after collection.&lt;/p&gt;&#xA;&lt;p&gt;Positions of the floats that have delivered data within the last 30 days :&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NXWCa.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NXWCa.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-11-02T09:46:39.423" Title="How is the distribution of Argo floats managed over the Earth's oceans?" Tags="|temperature|measurements|ocean-currents|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15488" PostTypeId="2" ParentId="15486" CreationDate="2018-11-02T09:46:39.423" Score="7" Body="&lt;p&gt;I think, there are two factors which prevent the forming of clusters of floats:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The floats' lifespan. Batteries supposedly last &lt;a href=&quot;http://www.argo.ucsd.edu/FAQ.html#power&quot; rel=&quot;noreferrer&quot;&gt;for four years&lt;/a&gt;, then the floats become debris which sink to the bottom of the ocean (yeah, not that great from an environmentalist point of view). So the lifespan of the battery prevents the floats from clustering.&lt;/li&gt;&#xA;&lt;li&gt;The introdcution of new floats. Derelic floats are replaced by new ones to keep the network working. Naturally, these new floats are placed somewhere in the ocean, where they don't end up immediately in a gyre but will most likely provide the most possible diversity of data.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="14194" LastActivityDate="2018-11-02T09:46:39.423" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15489" PostTypeId="2" ParentId="13931" CreationDate="2018-11-02T10:57:37.257" Score="1" Body="&lt;p&gt;Basically, hazyness mostly comes down to particles in the atmosphere (aerosols). Could be water, could be soot and other exhaust from fires or combustion engines, could be simply dust. Sometimes differences in temperature obscure the horizon, too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In your case my first guess is dust, most likely from northern Africa, which is blown north, out over the sea.&lt;/p&gt;&#xA;" OwnerUserId="14194" LastEditorUserId="14194" LastEditDate="2018-11-02T12:23:56.357" LastActivityDate="2018-11-02T12:23:56.357" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15491" PostTypeId="1" AcceptedAnswerId="15503" CreationDate="2018-11-02T12:25:06.100" Score="7" ViewCount="256" Body="&lt;p&gt;There are various physical, chemical and biological processes that free up hydrogen from molecules (often hydrocarbons or water).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once in the atmosphere, the hydrogen is lost to space (the Earth's gravity is too weak to hold onto it). So the Earth is losing hydrogen to space (perhaps at a very slow rate).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any interaction between the Earth's atmosphere and high velocity protons in the solar wind (e.g. protons combining with atmospheric oxygen to form hydroxide) which is capable of balancing the hydrogen loss? How big is the hydrogen loss? Is the amount of hydrogen on Earth in equilibrium?&lt;/p&gt;&#xA;" OwnerUserId="14203" LastActivityDate="2018-11-05T02:29:31.840" Title="Is there an atmospheric hydrogen cycle?" Tags="|atmosphere|atmospheric-chemistry|solar-terrestrial-physics|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15492" PostTypeId="2" ParentId="15476" CreationDate="2018-11-02T13:25:47.123" Score="3" Body="&lt;p&gt;The answer to your question is 'yes': you can probe a medium of arbitrary complexity using sound waves, and relate the propagating wave to the physical properties encountered on its path: the stiffness (Hooke's law), density (Newton's law), and you can locate the layers by figuring out where the stiffness and density change. If the competition only requires you to submit a hypothetical method, such a seismological method certainly fits the bill.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, when it comes to practically implementing such a method; I advice against it. You'll find too many obstacles on your path that require expert input and money. For example:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;You require a very well controlled source: you need to know exactly the source function (the wavelet) that ends up in your medium; which is distorted by the actuator's frequency response, and which is distorted by the usually weak coupling between your source and the medium.&lt;/li&gt;&#xA;&lt;li&gt;You require a high-resolution receiver as well, to record the signal that propagated within the medium, which is similarly not trivial to create.&lt;/li&gt;&#xA;&lt;li&gt;After you have solved these (difficult!) problems, you have to turn your recording at the surface into a quantitative 2-D/3-D physical model of the Earth, i.e. a model that tells you the velocity of the medium and the thickness of each layer. This requires extensive data-processing and typically requires many numerical wave simulations; only then, when your numerical simulation predicts data that resembles the data that you recorded, you may assume that you may have found the approximate physical state of the medium. This technique is called &lt;a href=&quot;https://wiki.seg.org/wiki/Full-waveform_inversion&quot; rel=&quot;nofollow noreferrer&quot;&gt;Full-Waveform Inversion&lt;/a&gt;, and is the only one I'm aware of that will provide the answer to all your questions.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The problems in the last point are due to the fact that surface recordings provide a massively underdetermined problem. Say, as an example that you drop a weight onto the medium, and then it takes 100ms before you hear the first echo come from the medium. Then you infer that the wave traveled back and forth to depth with a certain velocity. This gives an equation: &lt;span class=&quot;math-container&quot;&gt;$100\ \text{ms} \approx \frac{2h}{V}$&lt;/span&gt; that doesn't reveal what the depth &lt;span class=&quot;math-container&quot;&gt;$h$&lt;/span&gt; actually is or what the velocity &lt;span class=&quot;math-container&quot;&gt;$V$&lt;/span&gt; actually is! The problem is thus poorly constrained by the data, and you require a lot of data to get a good understanding of the subsurface. Then, furthermore, your waves propagate in an elastic medium which excites many types of waves: compressional waves, shear waves, surface waves, &lt;span class=&quot;math-container&quot;&gt;$\dots$&lt;/span&gt;,  which all travel at different speeds and are sensitive to different physical properties. You require some good data-processing to isolate only the wave that you are interested in!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As said in the comments, the size of the medium is no limitation, you simply scale up the wave's frequencies to the ultra-sound region! It is generally thought that you can locate objects in the Earths subsurface when they are separated by a distance &lt;span class=&quot;math-container&quot;&gt;$d\geq\lambda/2$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$\lambda=\frac{V}{f}$&lt;/span&gt; is the wavelength, with &lt;span class=&quot;math-container&quot;&gt;$V$&lt;/span&gt; the velocity of the medium and &lt;span class=&quot;math-container&quot;&gt;$f$&lt;/span&gt; the wave's frequency. The average speed of a compressional wave in rocks is about 5km/s, thus you require a frequency of at least &lt;span class=&quot;math-container&quot;&gt;$f=\frac{5\,000\ \text{m/s}}{2d\ \text{m}}$&lt;/span&gt; to find your object of size &lt;span class=&quot;math-container&quot;&gt;$d$&lt;/span&gt;. If you resolution requires separation up to 1cm, you require a wave with a frequency of at least 80 &lt;span class=&quot;math-container&quot;&gt;$\text{kHz}$&lt;/span&gt;: well into the ultra-sound territory!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm sorry to give such a demotivating answer, but seismology is simply too complex to be a viable project for anything but a fully-fledged multi-year commercial or PhD project. My suggestion would be to build a variation to a &lt;a href=&quot;https://en.wikipedia.org/wiki/Cone_penetration_test&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cone Penetration Test&lt;/a&gt;, which measures the resistance to pushing a cone into the ground (which is directly related to the hardness of the rock!) at a fixed speed. Whenever the resistance changes you are encountering a new layer, such that the size and number of layers is easily inferred. That would satisfy all the requirements, I think. Then again, I have no expertise with the Cone Penetration Test, and perhaps it is not as easy as I think...&lt;/p&gt;&#xA;" OwnerUserId="12155" LastEditorUserId="12155" LastEditDate="2018-11-02T14:49:58.740" LastActivityDate="2018-11-02T14:49:58.740" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15493" PostTypeId="1" CreationDate="2018-11-02T22:00:25.220" Score="3" ViewCount="49" Body="&lt;p&gt;We have been thinking of using Aerostats/Balloons for an environmental monitoring project in our university. We have been considering 2 options: Tethered Aerostats (which fly upto 1 km) and Stratospheric Aerostats (upto 20 - 30 km).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I was exploring the available options, I was surprised to find that Tethered Aerostats (i.e. low-altitude balloons, within 1km) have much less persistence in air than Stratospheric Balloons. E.g. Airstar's &lt;a href=&quot;http://airstar.aero/en/tethered-balloons-range/&quot; rel=&quot;nofollow noreferrer&quot;&gt;tethered balloons have maximum persistence of 15 days&lt;/a&gt; while their &lt;a href=&quot;http://airstar.aero/en/stratospheric-balloons/&quot; rel=&quot;nofollow noreferrer&quot;&gt;stratospheric versions can hover for upto 6 months&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the reason? Is it the wind speed? Or less density (but how would it affect)? Or maybe it's just they are designing the stratospheric balloons to last longer?&lt;/p&gt;&#xA;" OwnerUserId="13023" LastActivityDate="2018-11-02T22:00:25.220" Title="Why do tethered aerostats have lower persistence than stratospheric balloons?" Tags="|meteorology|atmosphere|weather-satellites|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="15495" PostTypeId="1" CreationDate="2018-11-03T11:26:52.003" Score="1" ViewCount="93" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/M9A5U.jpg&quot; alt=&quot;enter image description here&quot;&gt; i found this amongst some river rock. Please explain why or what happened to it.&lt;/p&gt;&#xA;" OwnerUserId="14210" LastActivityDate="2018-11-04T15:30:53.237" Title="Please explain how this rock could be shaped like this" Tags="|geology|" AnswerCount="1" CommentCount="1" ClosedDate="2018-11-05T09:07:42.423" ContentLicense="CC BY-SA 4.0" />
  <row Id="15496" PostTypeId="2" ParentId="15495" CreationDate="2018-11-03T17:10:10.497" Score="3" Body="&lt;p&gt;These are fossil burrows... Looks like Thalassinoides or something similar. They are made by fishes, sea anemones, and crustaceans and can occur in different shapes... elongated, rounded, ending in t-sections, straight, spiral-shaped. A scalebar would be helpful for further classification.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/s13GS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/s13GS.jpg&quot; alt=&quot;One version of classical Thalassinoides&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.m.wikipedia.org/wiki/Thalassinoides&quot; rel=&quot;nofollow noreferrer&quot;&gt;Take a look at the Wikipedia page about it&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="13398" LastEditorUserId="13398" LastEditDate="2018-11-04T15:30:53.237" LastActivityDate="2018-11-04T15:30:53.237" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15498" PostTypeId="1" AcceptedAnswerId="15505" CreationDate="2018-11-03T22:22:09.947" Score="1" ViewCount="995" Body="&lt;p&gt;The landsat 7 etm+ users handbook does the the Dn to top atmosphere correction (pages 79-80, link below). Is this applicable to landsat 5 tm as well?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://landsat.usgs.gov/sites/default/files/documents/LSDS-1927_L7_Data_Users_Handbook.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Landsat 7 User Handbook&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14152" LastActivityDate="2018-11-05T11:26:04.747" Title="Landsat 5 DN's to Top of Atmosphere reflectance" Tags="|satellites|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15500" PostTypeId="1" CreationDate="2018-11-04T06:30:29.173" Score="1" ViewCount="370" Body="&lt;p&gt;If a nursery sells plants, I'm wondering what a place that sells rocks is called. Something where they offer rocks of various sizes like &lt;a href=&quot;https://www.classicrockinc.com/our-products/gravel-river-rock&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eeQIb.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eeQIb.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Well, those are all river rocks, but I'm wondering about for any rocks, even boulders or &quot;slices&quot; (or perhaps &quot;slates&quot;). In bulk/wholesale and retail. Perhaps a standard reference/source that has them would be nice but not necessary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am interested to know how rocks are harvested, what the process and distribution is and such.&lt;/p&gt;&#xA;" OwnerUserId="784" LastActivityDate="2018-11-04T06:30:29.173" Title="What a place that sells rocks is called" Tags="|rocks|open-data|" AnswerCount="0" CommentCount="2" ClosedDate="2018-11-04T14:07:04.000" ContentLicense="CC BY-SA 4.0" />
  <row Id="15502" PostTypeId="2" ParentId="14985" CreationDate="2018-11-05T02:12:17.240" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;We know that terrestrial hydrogen reaches space because ultraviolet images reveal&#xA;  a halo of hydrogen atoms surrounding the Earth (Fig. 2). Some of these atoms are&#xA;  escaping while the rest are trapped. The temperature at Earth’s exobase is typically around&#xA;  1000 K, although it varies as the Sun’s ultraviolet output cycles up and down every 11&#xA;  years or so. At 1000 K, hydrogen atoms have an average speed of 5 km/sec, which is&#xA;  below Earth’s escape velocity of 10.8 km/sec at the exobase. Yet hydrogen atoms still&#xA;  manage to escape because many move faster than average. This loss of particles from the&#xA;  energetic tail of the speed distribution is called “Jeans’ escape” after James Jeans (from the&#xA;  University of Cambridge), who described it mathematically in the early twentieth century.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://geosci.uchicago.edu/~kite/doc/Catling2009.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;The escape of planetary atmospheres&lt;/a&gt; Catling &amp;amp; Zahnle, Scientific American,2009 1&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The exobase is the lower boundary of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Exosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;exosphere&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0j2NR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0j2NR.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I guess that two degrees increase in surface temperature would not make much difference to the &lt;span class=&quot;math-container&quot;&gt;$~1000K$&lt;/span&gt; at the exobase.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2018-11-05T16:46:17.810" LastActivityDate="2018-11-05T16:46:17.810" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15503" PostTypeId="2" ParentId="15491" CreationDate="2018-11-05T02:29:31.840" Score="4" Body="&lt;p&gt;&quot;Is there any interaction between the Earth's atmosphere and high velocity protons in the solar wind (e.g. protons combining with atmospheric oxygen to form hydroxide) which is capable of balancing the hydrogen loss?&quot; I found &lt;a href=&quot;https://www.seeker.com/the-solar-wind-is-an-interplanetary-water-factory-1768239502.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hydrogen ions in the solar wind react with oxygen in interplanetary dust grains to form little packets of water, potentially supplying Earth with its water&lt;/a&gt;, but they don't know how much.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;How big is the hydrogen loss?&quot; &lt;a href=&quot;https://geosci.uchicago.edu/~kite/doc/Catling2009.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;3 kilograms per second&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Is the amount of hydrogen on Earth in equilibrium?&quot; We are also gaining 50,000 tons of matter per year from space dust, but only a small part of that is hydrogen.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2018-11-05T02:29:31.840" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15505" PostTypeId="2" ParentId="15498" CreationDate="2018-11-05T11:16:59.943" Score="1" Body="&lt;p&gt;Short answer: yes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Radiance to Reflectance correction described in the Handbook is just physics based. Therefore, it is valid for any Earth observing satellite. However, the mean solar exo-atmospheric irradiances (table 5-2) are specific to the wavelength bands of the ETM+ sensor. Therefore, if you want to correct other bands you would need new coefficients valid for the corresponding wavelength range.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But in the case of Landsat 5 and 7, the bands are almost identical (with very small differences on bands 4 and 7). Therefore, unless you need very high accuracy I would say that it is safe to use ETM+ coefficient (Landsat 7) to correct TM imagery (Landsat 4 and 5).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The bands for TM and ETM+ are as follows:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/32D4C.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/32D4C.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/M6LjF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/M6LjF.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(taken from &lt;a href=&quot;https://landsat.usgs.gov/what-are-band-designations-landsat-satellites&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS Landsat Mission&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that it is not only the boundaries of the bands what matter, but also the spectral response within the band. Therefore, even for bands that seem identical, the coefficients of exo-atmospheric irradiances can present small differences.&#xA;Ideally, you should use the coefficients calculated specifically for the TM sensor, but using the ETM+ values would provide a very good approximation. At least good enough for most applications. But if you want to use the TM specific values, they are as follows:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gMIiO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gMIiO.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Taken from USGS Q&amp;amp;A &quot;&lt;a href=&quot;https://landsat.usgs.gov/esun&quot; rel=&quot;nofollow noreferrer&quot;&gt;Where can I find the solar exoatmospheric spectral irradiances (ESUN) for the Landsat 1-5 MSS, Landsat 4-5 TM, and Landsat 7 ETM+ sensors?&lt;/a&gt;&quot;)&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-11-05T11:26:04.747" LastActivityDate="2018-11-05T11:26:04.747" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="15506" PostTypeId="1" CreationDate="2018-11-05T15:01:17.547" Score="4" ViewCount="563" Body="&lt;p&gt;What is the exact difference between GFS 0.25 and GDAS 0.25 data which is available in &lt;a href=&quot;http://nomads.ncep.noaa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://nomads.ncep.noaa.gov/&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And are the GFS 0.5 and 1 degree data available in the above url and &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/model-data/model-datasets/global-forcast-system-gfs&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; the same?&lt;/p&gt;&#xA;" OwnerUserId="14223" LastActivityDate="2018-11-05T15:01:17.547" Title="Difference between GDAS and GFS data" Tags="|meteorology|models|weather-forecasting|gfs|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15507" PostTypeId="2" ParentId="7754" CreationDate="2018-11-05T21:07:46.107" Score="1" Body="&lt;p&gt;There is &lt;em&gt;evidence&lt;/em&gt; that at least part of the erosion in the Grand Canyon was caused by an outflow flood caused by the failure of a lava dam.  &lt;a href=&quot;https://www.gcrg.org/bqr/18-1/lava.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.gcrg.org/bqr/18-1/lava.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is &lt;em&gt;speculation&lt;/em&gt; that glacial lake outflow floods from the glaciers in western Colorado at the end of the last ice age could have contributed as well.  More study is needed to prove or disprove that one.&lt;/p&gt;&#xA;" OwnerUserId="14224" LastActivityDate="2018-11-05T21:07:46.107" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15509" PostTypeId="1" CreationDate="2018-11-06T04:39:23.957" Score="6" ViewCount="1143" Body="&lt;p&gt;Landsat 5 tm  reflectance product images are delivered as signed 16 bit images, why is this preferred to unsigned 8 bit that the DN's are stored as level 1 products for the same satellite? Look at table 6-1 on page 19 of the following document: &lt;a href=&quot;https://landsat.usgs.gov/sites/default/files/documents/ledaps_product_guide.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://landsat.usgs.gov/sites/default/files/documents/ledaps_product_guide.pdf&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="14152" LastEditorUserId="106" LastEditDate="2018-11-07T09:28:31.293" LastActivityDate="2018-12-19T06:21:36.730" Title="Why is satellite imagery data delivered as signed 16 bit integers?" Tags="|remote-sensing|data-formats|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="15512" PostTypeId="1" CreationDate="2018-11-06T11:47:42.643" Score="1" ViewCount="43" Body="&lt;p&gt;Is there in some ftp storage, a pre-processing CMIP5 data for direct download in netcdf extention? &lt;/p&gt;&#xA;" OwnerUserId="14230" LastActivityDate="2018-11-06T11:47:42.643" Title="Seeking CMIP5 or CMIP6 globally in .nc format" Tags="|climate-change|models|atmosphere-modelling|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15516" PostTypeId="1" CreationDate="2018-11-06T23:57:57.783" Score="1" ViewCount="306" Body="&lt;p&gt;Wondering if there is any GIS data available for mining operations in any places in the world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I looked here but didn't find much:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://catalog.data.gov/dataset?tags=mines&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://catalog.data.gov/dataset?tags=mines&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.eia.gov/survey/#coal&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.eia.gov/survey/#coal&lt;/a&gt; (these just look like a bunch of pdf forms, I didn't find any data).&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://pubs.er.usgs.gov/search?q=coal&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://pubs.er.usgs.gov/search?q=coal&lt;/a&gt; (such as &lt;a href=&quot;https://pubs.er.usgs.gov/publication/ofr20121205&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;, which seems to have some &lt;a href=&quot;https://pubs.usgs.gov/of/2012/1205/Downloads/&quot; rel=&quot;nofollow noreferrer&quot;&gt;data&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Am looking for open data not in PDF form, but if it only exists in PDF form then that would be okay. A better form would be CSV or shapefile.&lt;/p&gt;&#xA;" OwnerUserId="784" LastEditorUserId="1149" LastEditDate="2018-11-12T14:16:39.177" LastActivityDate="2018-11-22T13:54:42.290" Title="Open Mining facility/operation GIS data" Tags="|open-data|database|coal|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15517" PostTypeId="1" CreationDate="2018-11-07T03:53:37.227" Score="2" ViewCount="81" Body="&lt;p&gt;There seems to be many options for a single problem, but each with different approaches and complications, and that makes is confusing and time consuming for this beginner to work out which to use.  I'd like to make an image like:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/q3eqK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/q3eqK.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each solution/environment/analysis platform seems to have particular benefits, but also perhaps things missing, and each takes a while to learn and surmise its feasibility and adaptability.  I'm worried I'll get involved in a software that ends up more difficult or only useful in a certain limited aspects of my study/investigation/research. Some famous platforms used in earth science look to be matlab, R, IDL, NCL, grids, COD, Fortran, ArcGIS, geode, global mapper, eradas, e.t.c.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Among all of these which one is more user friendly, easier to learn, and more efficient for making a plot similar to the one attached?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="12714" LastEditorUserId="6298" LastEditDate="2018-11-07T23:51:28.787" LastActivityDate="2018-11-07T23:51:28.787" Title="Which software is easiest to use to create plots like these?" Tags="|climate-change|geography|snow|" AnswerCount="0" CommentCount="9" ClosedDate="2018-11-07T15:36:17.887" ContentLicense="CC BY-SA 4.0" />
  <row Id="15519" PostTypeId="2" ParentId="15427" CreationDate="2018-11-07T12:04:11.127" Score="2" Body="&lt;p&gt;I think (but I'm not an expert on the topic) that your assumption is wrong! The &lt;em&gt;pore fluid pressure&lt;/em&gt; and &lt;em&gt;effective pressure exerted on the rock&lt;/em&gt; are not identical. And during log measurements, it is only the pore fluid pressure that is measured, &lt;span class=&quot;math-container&quot;&gt;$\sigma_\text{pore}=\rho_\text{water}gz$&lt;/span&gt;. As long as the water is connected through pores to the earth's surface and it is assumed to be hydrostatic (not-flowing), the measured pressure in the pores will create a pressure to push up the overlying water only -- the rocks will take care of carrying the overlying rocks themselves! If you'd drill a borehole, the water-filled column would be filled with water exactly to the earth's surface. The effective pressure on the whole system is then &lt;span class=&quot;math-container&quot;&gt;$\sigma_\text{effective}=\sigma_\text{lithostatic}-\sigma_\text{pore}$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, once a seal is formed (e.g., a shale formation overlies a formation), the pore water suddenly has to also carry the overlying rock formation! The pressure will then increase significantly, and the pore water pressure that you measure becomes more similar to the effective pressure. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The pore water pressure thus increased below a seal because it is stuck. Once you drill a hole from the surface to this formation, you allow water to flow freely to the surface, and it is clear that it is under overpressure with respect to the lithostatic pressure, because it will blow out!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See also this comprehensive set of slides: &lt;a href=&quot;http://ocw.utm.my/pluginfile.php/1509/mod_resource/content/0/To_upload_OCW_Formation_pressures.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://ocw.utm.my/pluginfile.php/1509/mod_resource/content/0/To_upload_OCW_Formation_pressures.pdf&lt;/a&gt; .&lt;/p&gt;&#xA;" OwnerUserId="12155" LastEditorUserId="12155" LastEditDate="2018-11-07T13:49:45.197" LastActivityDate="2018-11-07T13:49:45.197" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15520" PostTypeId="1" AcceptedAnswerId="15521" CreationDate="2018-11-07T13:09:22.183" Score="3" ViewCount="1770" Body="&lt;p&gt;I can understand places like a desert where it's too dry or tundra where it's too cold, but why are there places like meadows or fields in the middle of the forest where trees don't grow? Or even large areas like prairies?&lt;/p&gt;&#xA;" OwnerUserId="14239" LastActivityDate="2018-11-07T14:17:56.327" Title="Why are there places where trees don't grow?" Tags="|geobiology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15521" PostTypeId="2" ParentId="15520" CreationDate="2018-11-07T14:17:56.327" Score="4" Body="&lt;p&gt;A non-conclusive list:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;frequent wildfires&lt;/li&gt;&#xA;&lt;li&gt;not enough water&lt;/li&gt;&#xA;&lt;li&gt;too much water&lt;/li&gt;&#xA;&lt;li&gt;bad soil conditions&lt;/li&gt;&#xA;&lt;li&gt;average temperatures too high or low&lt;/li&gt;&#xA;&lt;li&gt;not enough sunlight&lt;/li&gt;&#xA;&lt;li&gt;animals&lt;/li&gt;&#xA;&lt;li&gt;human intervention&lt;/li&gt;&#xA;&lt;li&gt;other vegetation is better adapted to local conditions and thus suppress growing trees&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="14194" LastActivityDate="2018-11-07T14:17:56.327" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15523" PostTypeId="1" CreationDate="2018-11-07T21:32:02.270" Score="2" ViewCount="169" Body="&lt;p&gt;I'm pretty new to all this...  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've recently purchased a Geiger counter, and am hoping to locate rocks like pitchblende and other radioactive minerals for my collection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm based in the North West of England in Manchester and looking for any hot spots nearby for which to go to and search!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there maps available, or any hints as to what types of locations I should be seeking to start my search?&lt;/p&gt;&#xA;" OwnerUserId="14243" LastEditorUserId="6298" LastEditDate="2018-11-07T21:44:53.657" LastActivityDate="2018-11-09T08:38:29.093" Title="Where to start searching to find more radioactive minerals?" Tags="|geology|minerals|radioactivity|uranium|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="15525" PostTypeId="1" AcceptedAnswerId="15537" CreationDate="2018-11-07T23:55:12.010" Score="2" ViewCount="301" Body="&lt;p&gt;I am in the process of learning what sort of data is collected with &lt;a href=&quot;https://www.conservapedia.com/Radiometric_dating&quot; rel=&quot;nofollow noreferrer&quot;&gt;radiometric dating techniques&lt;/a&gt;, used for &lt;a href=&quot;https://en.wikipedia.org/wiki/Absolute_dating#Radiometric_techniques&quot; rel=&quot;nofollow noreferrer&quot;&gt;absolute dating&lt;/a&gt;. It sounds like there are two primary ones:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Radiocarbon_dating&quot; rel=&quot;nofollow noreferrer&quot;&gt;Radiocarbon dating&lt;/a&gt; (~50k year scale)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/K%E2%80%93Ar_dating&quot; rel=&quot;nofollow noreferrer&quot;&gt;Potassium-argon dating&lt;/a&gt; (billion year scale)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Then in between is tree ring dating, but that is a separate thing. And for completeness, there is also a sort of &lt;a href=&quot;https://en.wikipedia.org/wiki/Thermoluminescence_dating&quot; rel=&quot;nofollow noreferrer&quot;&gt;luminescence dating technique&lt;/a&gt; which I have never heard of. In this question I am just wondering about the Radiometric techniques. There is also Uranium-lead dating, but I don't see much info on that one, so focusing here just on carbon and potassium-argon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, I am wondering if there are any data formats used for storing the data (which will help with search). I searched around a bit but didn't find anything. Second, I'm wondering if there are any data repositories containing radiometric datasets, just to get started. And third, if there's not any &quot;centralized repositories&quot; of this sort of data, and instead it is by individual author in their own style, that might be good to know, just so I don't think I'm missing something obvious.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At first I found &lt;a href=&quot;ftp://ftp.ncdc.noaa.gov/pub/data/paleo/coral/east_pacific/uva_island_1995.txt&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; from &lt;a href=&quot;https://catalog.data.gov/dataset?tags=radiocarbon&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;GEOGRAPHIC REGION: Tropical Pacific&#xA;&#xA;DESCRIPTION:&#xA;Pacific Bomb Radiocarbon Coral Data.&#xA;&#xA;Uva island, Gulf of Chiriqui, Panama (7°48'N, 81°45'W),&#xA;&#xA;&#xA;CUVA; Uva island, Gulf of Chir(7°48'N, 81°45'W)&#xA;                              Druffel, ERM(1987). JMR, 45:667-698&#xA;Gardinesoseris planulata&#xA;collected July 1980 Collected by: P. Glynn&#xA;&#xA;   WH#       YEAR      ¯14C   ERROR&#xA;    42    1950-1951    -64       ±3-4‰   for the whole&#xA;    43    1952-1953    -59     data set&#xA;    68    1952-1954    -58&#xA;    69       1955      -51&#xA;    70       1956      -46&#xA;    71       1957      -47&#xA;    72       1958      -45&#xA;    73       1959      -37&#xA;    74       1960      -42&#xA;    75       1961      -24&#xA;   115       1962      -26&#xA;   109       1963      -22&#xA;   110       1964      -23&#xA;   106       1965       29&#xA;   112       1966       46&#xA;   108       1967       34&#xA;   111       1968       66&#xA;   113       1969       74&#xA;   114       1970       70&#xA;    96       1972       75&#xA;    94       1973       67&#xA;    99       1974       70&#xA;    92       1975       56&#xA;    95       1976       43&#xA;    93       1977       54&#xA;    91       1978       52&#xA;    97       1979       74&#xA;    98       1980       73&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;But that doesn't look like much, basically some sort of in integer value for each year. I'm wondering if there is a lot more data typically, such as like you would find in mass spectrometry or crystallography or something. Or if it is literally just an integer or decimal number without anything else (like probability of correctness or other things). Like I'm wondering if the data is much more complicated and would look along the lines of &lt;a href=&quot;http://www.c14dating.com/agecalc.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.c14dating.com/agecalc.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rHzCM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also found &lt;a href=&quot;https://mrdata.usgs.gov/radiometric/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; which I haven't looked too much into yet. And &lt;a href=&quot;https://d28rz98at9flks.cloudfront.net/70219/70219.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; (which unfortunately is a PDF), which has a bunch of maps. So it seems like the data would be some sort of GIS shapefile or something perhaps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If it matters, I am interested in particular in fossil radiometric data.&lt;/p&gt;&#xA;" OwnerUserId="784" LastEditorUserId="784" LastEditDate="2018-11-08T00:12:17.403" LastActivityDate="2018-11-09T09:20:31.310" Title="Radiometric dating data sets" Tags="|open-data|geochronology|radioactivity|dating|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15529" PostTypeId="2" ParentId="6676" CreationDate="2018-11-08T11:25:08.543" Score="1" Body="&lt;p&gt;The circumference of the Earth at the equator is ~40,075km.&#xA;Given that each UTM Zone is 6 degrees spaced in Longitude, there are then 60 UTM Zones around the globe.&#xA;Each Zone is thus 40,075/60 or ~668km at the equator (less towards the poles).&#xA;The central Easting for each Zone is 500km, therefore the max and min Easting for each Zone is 500+668/2 (834km) and 500-668/2 (166km). These max and min Easting values clearly diminish at higher Lattitudes.&lt;/p&gt;&#xA;" OwnerUserId="14247" LastActivityDate="2018-11-08T11:25:08.543" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15530" PostTypeId="2" ParentId="15525" CreationDate="2018-11-08T15:02:17.870" Score="1" Body="&lt;p&gt;There are huge datasets of geochronology available in the published literature. Unfortunately there is not one single database because the task is daunting (there are several thousand geochronology labs in the world which typically produce hundreds of ages per year).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some papers discussing how data should be (and often are) reported are these, for example :&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ldeo.columbia.edu/res/fac/argon/Publications/renne%20et%20al%202009%20QG.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;40Ar/39Ar geochronology&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.princeton.edu/geosciences/people/schoene/pdf/4_10_Schoene_UThPb_geochronology.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;U-Pb geochronology&lt;/a&gt; (with discussion on sources of error)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S1871101416301479&quot; rel=&quot;nofollow noreferrer&quot;&gt;U-Series geochronology&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.geochron.org/geochronsearch.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;This is a nice database (for U-Pb data by a few labs only for parts of the US)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://mrdata.usgs.gov/geochron/map-us.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here is a link to the USGS geochronology database in map format.&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="4783" LastEditorUserId="4783" LastEditDate="2018-11-09T07:40:25.020" LastActivityDate="2018-11-09T07:40:25.020" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15533" PostTypeId="1" CreationDate="2018-11-08T19:44:53.493" Score="4" ViewCount="213" Body="&lt;p&gt;Will bright indirect light cause an amethyst crystal to fade?&#xA;How about an overhead LED light?&#xA;How is best to preserve the color of my amethyst geode?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;" OwnerUserId="14250" LastActivityDate="2018-11-08T19:44:53.493" Title="how best to preserve the color of my amethyst geode?" Tags="|geology|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15535" PostTypeId="2" ParentId="924" CreationDate="2018-11-09T00:12:34.093" Score="0" Body="&lt;p&gt;In terrestrial biogeochemistry models, or TBMs, diagnostic models assimilate remote sensing observations while prognostic models are driven by forcing data [&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/97GB01936&quot; rel=&quot;nofollow noreferrer&quot;&gt;source]&lt;/a&gt;. This is because diagnostic models are used to diagnose the representation of processes in models (i.e., validation) while prognostic models are used to predict future states (i.e., forecasting). Perhaps the most well-known diagnostic model is CASA&lt;a href=&quot;http://cquest.arc.nasa.gov:8399/casa/&quot; rel=&quot;nofollow noreferrer&quot;&gt; [link]&lt;/a&gt;. This distinction no longer exists in most current models, as they may perform diagnosis or prognosis in different modes.&lt;/p&gt;&#xA;" OwnerUserId="14252" LastActivityDate="2018-11-09T00:12:34.093" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15536" PostTypeId="1" AcceptedAnswerId="16503" CreationDate="2018-11-09T01:57:58.640" Score="9" ViewCount="1707" Body="&lt;p&gt;It is well known that oceanic plates subduct under continental plates. This may be attributed to the plate's age and density, plus the water on top of it.&lt;br&gt;&#xA;So I was wondering if it is ever possible for a continental plate to subduct under an oceanic plate, perhaps if the oceanic plate is covered with shallow water? I've tried to search up on this question on many search engines and sites but to no avail. Thanks for your answer! &lt;/p&gt;&#xA;" OwnerUserId="14253" LastEditorUserId="6298" LastEditDate="2018-11-09T05:02:57.103" LastActivityDate="2019-03-18T17:17:09.477" Title="Is it ever possible for an continental plate to subduct under an oceanic plate?" Tags="|geology|plate-tectonics|subduction|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="15537" PostTypeId="2" ParentId="15525" CreationDate="2018-11-09T08:29:45.620" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;It sounds like there are two primary ones:&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No, these are not the two &quot;primary ones&quot;. The method used depends on what you are dating, and what age you expect it to be.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Radiocarbon dating is relevant to things younger than a few tens of thousands of years, and it's only relevant for things that were living (or growing), and incorporated atmospheric carbon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other methods such as U–Pb (the &quot;gold standard&quot; when dating igneous rocks), Rb–Sr, Re–Os, Sm–Nd, K(Ar)–Ar, Lu–Hf, and many more, are used for older things in the millions to billions of years. The one used depends on what you're analysing (Re–Os for sulfide minerals, U–Pb for zircons, Rb–Sr for micas, Sm–-Nd or Lu–Hf for garnets), and what is present in the rock, and what has textural evidence for being preserved.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might call U–Pb on zircon the &quot;primary&quot; one, because most of the dating is done on zircon. It's robust, easy, gives good ages, quick and relatively cheap.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;First, I am wondering if there are any data formats used for storing the data (which will help with search). &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Most U–Pb data is reduced using &lt;a href=&quot;http://bgc.org/isoplot_etc/isoplot.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;IsoPlot&lt;/a&gt;, so the data will look like something that came out of that software. But in general, no. There is no standardised  data format for geochronology, unfortunately.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;And third, if there's not any &quot;centralized repositories&quot; of this sort of data&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There are several of those. You can search &lt;a href=&quot;http://www.earthchem.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;EarthChem&lt;/a&gt;, that has some geochronological data. Australian government agencies also have some geochronology data in them, for example &lt;a href=&quot;http://www.ga.gov.au/data-pubs&quot; rel=&quot;nofollow noreferrer&quot;&gt;GA&lt;/a&gt; or &lt;a href=&quot;https://geoscience.nt.gov.au/gemis/ntgsjspui/community-list&quot; rel=&quot;nofollow noreferrer&quot;&gt;NTGS&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If it matters, I am interested in particular in fossil radiometric data.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Fossils are among the hardest thing to date. If the fossils are relatively young (few thousands of years), there's radiocarbon. Anything older than that, and it becomes much harder. There's &lt;a href=&quot;https://en.wikipedia.org/wiki/Uranium%E2%80%93thorium_dating&quot; rel=&quot;nofollow noreferrer&quot;&gt;U–Th disequilibrium&lt;/a&gt; series which may work for some slightly older fossils (~1 million years). Anything older than that in deep geological time has to be dated with indirect methods. Finding a database of that is probably wishful thinking, and to understand their dates you need to have some geological background to understand the geological relations and considerations that allow the indirect dating.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2018-11-09T09:20:31.310" LastActivityDate="2018-11-09T09:20:31.310" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15538" PostTypeId="2" ParentId="15523" CreationDate="2018-11-09T08:38:29.093" Score="1" Body="&lt;p&gt;You can try using the &lt;a href=&quot;https://www.mindat.org/countrylist.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;locality list at MinDat&lt;/a&gt;. Go to places that are easily accessible to you and see what minerals have been reported there. If there's something radioactive, it will probably be listed there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would remind you that radioactive minerals are, well, radioactive. These things are dangerous. I strongly recommend you find a different hobby. I deal with radioactive minerals as part of my job, and this is not something that you want to do unless you really know what you're doing. I remind you that a lot of the early researchers who worked on radioactivity died because they did not use the necessary precautions.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-11-09T08:38:29.093" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15539" PostTypeId="2" ParentId="3096" CreationDate="2018-11-09T13:03:23.543" Score="0" Body="&lt;p&gt;From our studies completed by spacecraft, that Mercury is geologically dead, because of the absence of obvious and recent geological activity on its surface, so no earthquakes.&#xA;However, the jury is still out on whether Venus is geologically active. There is widespread past vulcanism across its surface, and indeed there is a lot of evidence to suggest the surface of Venus is, geologically, quite young, but again, at the moment we don't know if the planet is active.&#xA;Mars is unlikely to be still active, and there is certainly no trace of plate tectonics, which is the biggest factor in volcanoes and earthquakes on the Earth. However, we will soon know if there are Marsquakes: NASA's InSight spacecraft has been designed to listen for them with seismometers pushed into the ground: it arrives at Mars in November this year. We actually don't know much about Mars' interior: soon, Insight will help us to see what's inside the planet.&lt;/p&gt;&#xA;" OwnerUserId="14255" LastActivityDate="2018-11-09T13:03:23.543" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15540" PostTypeId="2" ParentId="6566" CreationDate="2018-11-09T16:03:57.917" Score="2" Body="&lt;p&gt;Three very recent examples are&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.theguardian.com/world/2018/nov/02/japanese-island-disappears-esanbe-hanakita-kojima&quot; rel=&quot;nofollow noreferrer&quot;&gt;Esanbe Hanakita Kojima&lt;/a&gt; in Japan (disappeared between 2014 and 2018)&lt;/li&gt;&#xA;&lt;li&gt;Hawaii's &lt;a href=&quot;https://edition.cnn.com/2018/10/25/us/hawaii-island-hurricane-gone-wxc-trnd/&quot; rel=&quot;nofollow noreferrer&quot;&gt;East Island&lt;/a&gt; (wiped away by a Hurricane in 2018)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Sandy_Island,_New_Caledonia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sandy Island&lt;/a&gt; (&quot;undiscovered&quot; in 2012)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I wonder if there are any predictions concerning the future rate of such happenings.&lt;/p&gt;&#xA;" OwnerUserId="11295" LastActivityDate="2018-11-09T16:03:57.917" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15544" PostTypeId="1" CreationDate="2018-11-10T00:37:03.213" Score="4" ViewCount="118" Body="&lt;p&gt;This could be needed in the Worldbuilding stack exchange instead of here, but when I was mapping out the movements of the tectonic plates, then there's a few locations where oceanic and continental plates are moving parallel to one another in opposite directions, creating transform boundaries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can't find anything regarding the formations that would arise from this, though I expect that something along the lines of cliffs might form, though this is pure speculation. What formations should I expect?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And as a side-note, I also found many cases of when one plate is moving parallel to the boundary, but the other plate is moving either convergent or divergent of that boundary. What formations should I expect from these as well?&lt;/p&gt;&#xA;" OwnerUserId="14262" LastActivityDate="2018-11-10T05:59:16.077" Title="What formations are to be expected to develop between the transform boundaries of oceanic and continental plates?" Tags="|plate-tectonics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15547" PostTypeId="2" ParentId="15544" CreationDate="2018-11-10T05:59:16.077" Score="1" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/San_Andreas_Fault&quot; rel=&quot;nofollow noreferrer&quot;&gt;San Andreas Fault system&lt;/a&gt; is an excellent example of what can happen in an oceanic–continental transform fault.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's also important to remember that plate boundaries are usually never 100% transform-like and are at an angle. This would cause either compression or extension, depending on the local geometry. A &lt;a href=&quot;https://en.wikipedia.org/wiki/Pull-apart_basin&quot; rel=&quot;nofollow noreferrer&quot;&gt;pull apart basin&lt;/a&gt; is an example of something like this. For instance, the dead sea is a basin on a transform fault between Israel and Jordan, and a few hundreds kilometres to the north, on the same transform, you have mountains between Lebanon and Syria.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-11-10T05:59:16.077" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15558" PostTypeId="1" CreationDate="2018-11-12T13:10:55.173" Score="2" ViewCount="2151" Body="&lt;p&gt;I tried to convert segd format to su format using seismic unix by below command:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;segdread tape=1.segd &amp;gt; 1.su&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;but I have an error:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;segdread: Error with length of first record&#xA;    ... first record = 270320 bytes differs from ((1 + n_gh + n_str * (n_cs + n_sk) + n_ec + n_ex) * 32)&#xA;        with n_gh=2, n_str=1, n_cs=16, n_sk=0, n_ec=32, n_ex=32&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;I would be grateful if you could help me to fix it.&lt;/p&gt;&#xA;" OwnerUserId="14277" LastActivityDate="2020-03-22T19:09:36.663" Title="converting segd data to SU format using seismic unix" Tags="|seismic|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15559" PostTypeId="2" ParentId="15516" CreationDate="2018-11-12T14:09:27.770" Score="4" Body="&lt;p&gt;For the US, there are several sources:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://mrdata.usgs.gov/mrds/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mineral Resources Data System (MRDS)&lt;/a&gt;&#xA;MRDS is a collection of reports describing metallic and nonmetallic mineral resources throughout the world. Included are deposit name, location, commodity, deposit description, geologic characteristics, production, reserves, resources, and references. It subsumes the original MRDS and MAS/MILS.  As of 2011, USGS has ceased systematic updates to MRDS, and is working to create a new database, focused primarily on the conterminous US.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://catalog.data.gov/dataset/mas-mils-mineral-availability-system-mineral-industry-location-system-arc-info-point-coverage-f&quot; rel=&quot;nofollow noreferrer&quot;&gt;MAS/MILS:&lt;/a&gt; &#xA;This record is maintained in the National Geologic Map Database (NGMDB). The NGMDB is a Congressionally mandated national archive of geoscience maps, reports, and stratigraphic information, developed according to standards defined by the cooperators, i.e., the USGS and the Association of American State Geologists (AASG). Included in this system is a comprehensive set of publication citations, stratigraphic nomenclature, downloadable content, unpublished source information, and guidance on standards development. The NGMDB contains information on more than 90,000 maps and related geoscience reports published from the early 1800s to the present day, by more than 630 agencies, universities, associations, and private companies. For more information, please see &lt;a href=&quot;http://ngmdb.usgs.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://ngmdb.usgs.gov/&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://catalog.data.gov/dataset?tags=mines&quot; rel=&quot;nofollow noreferrer&quot;&gt;Data.Gov&lt;/a&gt; Mining related data set.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://digitalrockhound.blogspot.com/p/features.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Digital Rockhound's companion&lt;/a&gt; &#xA;(Shameless plug for my software, not free though). &#xA;I created a new user interface to search MRDS and MAS/MILS databases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For Canada: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nrcan.gc.ca/earth-sciences/geography/atlas-canada/selected-thematic-maps/16878&quot; rel=&quot;nofollow noreferrer&quot;&gt;Natural Resources Canada&lt;/a&gt;&#xA;This map depicts the location of Canada's principal producing mines for the given reference year. It includes locations for significant metallic, nonmetallic and industrial mineral mines (except clay products, peat, and most construction materials [most stone, sand and gravel]), coal mines, oil sands mines, and oil and gas fields across the country. Also depicted are the locations of significant metallurgical facilities across Canada. The data in this map are based on Natural Resources Canada's annual Map 900A – Principal mineral areas, producing mines, and oil and gas fields in Canada.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For Australia:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://data.gov.au/dataset/australias-mineral-resources-and-their-global-status&quot; rel=&quot;nofollow noreferrer&quot;&gt;Australia's mineral resources and their global status&lt;/a&gt;&#xA;Australia's known resources of a wide range of mineral commodities are considerable in comparison with rates of production. Australia has the worlds largest economic demonstrated resources of bauxite, lead, zinc, silver, ilmenite, rutile, zircon, tantalum, and uranium. In addition, Australia is ranked in the top three countries in the world for economic demonstrated resources of brown coal, copper, cobalt, gold, iron ore, manganese ore, nickel , gem/near-gem and industrial diamond. Despite a high rate of discovery of significant new mineral deposits, particularly since the 1950s, there is considerable potential for discovery of further mineral deposits in Australia. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://pid.geoscience.gov.au/dataset/ga/39134&quot; rel=&quot;nofollow noreferrer&quot;&gt;OZMin database&lt;/a&gt; (from site)&#xA;These data represent the OZMIN Oracle relational database containing geological and resource information for Australian mineral deposits. OZMIN has been compiled from published references and has been designed so that attribute information can be retrieved and analysed in relation to spatial data contained in geographic information systems. The national mineral deposits dataset contains data on over one thousand major and historically significant mineral deposits for 60 mineral commodities (including coal).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For United Kingdom:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.bgs.ac.uk/mineralsuk/planning/resource.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;MineralsUK&lt;/a&gt; &#xA;MineralsUK is the British Geological Survey (BGS) Centre for Sustainable Mineral Development. Facilitated by the BGS Minerals and Waste science programme, the Centre is a global leader in the compilation, provision and analysis of mineral statistics and the major UK national provider of spatial and statistical minerals information. We also carry out research in areas directly relevant to our user community, such as metallogenesis, land-use impacts of mineral extraction and geomaterials.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="1149" LastEditDate="2018-11-22T13:54:42.290" LastActivityDate="2018-11-22T13:54:42.290" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15561" PostTypeId="1" CreationDate="2018-11-13T01:22:56.730" Score="1" ViewCount="141" Body="&lt;p&gt;I've come across this question in a Petrophysics exercise regarding the Gamma Ray well logging. And I don't know how to solve it.&lt;/p&gt;&#xA;&lt;h3&gt;This is the &amp;quot;believed&amp;quot; AFAIK session&lt;/h3&gt;&#xA;&lt;p&gt;Natural radioactivity on a sedimentary environment is mainly due to a Potassium isotope (K&lt;sup&gt;40&lt;/sup&gt;), responsible for around 20% of total radiation, with a lower although reasonable contribution from Thorium (Th&lt;sup&gt;232&lt;/sup&gt;) and a variable Uranium (U&lt;sup&gt;235&lt;/sup&gt;) amount. Shalestones are rich in K&lt;sup&gt;40&lt;/sup&gt; and also has metallic ions as Th&lt;sup&gt;232&lt;/sup&gt; and U&lt;sup&gt;235&lt;/sup&gt;.&lt;/p&gt;&#xA;&lt;p&gt;For a sandstone, however, radioactivity can arise either from mineral content on the matrix or, the fluid content belonging to the formation or mainly from shale contamination.&lt;/p&gt;&#xA;&lt;h3&gt;End of the AFAIK session&lt;/h3&gt;&#xA;&lt;p&gt;&lt;strong&gt;Someone&lt;/strong&gt; suggested that younger the rocks, lesser the diagenesis and thus more presence of K&lt;sup&gt;40&lt;/sup&gt; bearing elements, like feldspar and mica. This results in a radioactivity not originated from the shale, so tertiary rocks would show more radioactivity. &lt;strong&gt;Someone else&lt;/strong&gt; pointed out that older doesn't mean more under diagenesis, which opposes to the first reasoning.&lt;/p&gt;&#xA;" OwnerUserId="14280" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-11-13T18:18:34.417" Title="Which is naturally more radioactive: a tertiary or cretaceous sandstone? Why?" Tags="|geology|geophysics|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15562" PostTypeId="1" CreationDate="2018-11-13T11:02:12.880" Score="1" ViewCount="32" Body="&lt;p&gt;Environmental flow (EF) is a widely used concept in river basin management and river ecology. There are more than 200 methods to estimate the flow that should be left to the rivers to ensure a sustainable resource management, and it is almost impossible to standardize a methodology that could be applied for each stream everywhere in the world. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although some global exercises have been performed (&lt;a href=&quot;http://www.iwmi.cgiar.org/resources/models-and-software/environmental-flow-calculators/&quot; rel=&quot;nofollow noreferrer&quot;&gt;IWMI for instance&lt;/a&gt;), in fact, the EF is extremely site and season specific: it depends on the natural conditions of the river, its hydrological, geo-morphological, and biological features, and its natural ecosystem. That for, the use of specific methodologies makes sense in the management of a specific river basin or a portion of it, but what about global hydrological analyses? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am setting up a global gridded hydrological analysis and, while accounting for water uses, I would like to set up a threshold under which the water withdrawal is not allowed. I am thinking of using a percentile of the historical modeled monthly time series of discharge spanning a period of about 30 years. This would allow to set the threshold to a value for each month that is a percentile of the historical undisturbed (natural, with no fragmentation or withdrawal) discharge, for each of the grid-cells. Is this an acceptable approximation? &lt;/p&gt;&#xA;" OwnerUserId="8087" LastEditorUserId="8087" LastEditDate="2018-11-14T15:13:01.340" LastActivityDate="2018-11-14T15:13:01.340" Title="Environmenal flow in the context of global gridded hydrological analyses" Tags="|hydrology|water|environmental-protection|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15563" PostTypeId="1" AcceptedAnswerId="15579" CreationDate="2018-11-13T19:08:42.700" Score="2" ViewCount="174" Body="&lt;p&gt;According to the &lt;a href=&quot;https://www.arb.ca.gov/cc/inventory/data/data.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;California Air Resources Board&lt;/a&gt;, in 2016 (the most recent year for which figures appear to available) California's total greenhouse gas emissions were 430 million metric tons CO&lt;sub&gt;2&lt;/sub&gt; equivalent, of which 83% were actual CO&lt;sub&gt;2&lt;/sub&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In view of a record-breaking string of wildfires in California this year, I am wondering how significant the emission of greenhouse gases from such fires is, but I am having trouble finding relevant data on the internet. What I did find is a &lt;a href=&quot;https://insideclimatenews.org/content/chart-daily-co2-emissions-california-wildfires&quot; rel=&quot;nofollow noreferrer&quot;&gt;chart of &lt;em&gt;daily&lt;/em&gt; CO&lt;sub&gt;2&lt;/sub&gt; emissions&lt;/a&gt; during large wildfires earlier this year, which appears to indicate up to an &lt;em&gt;additional&lt;/em&gt; 1.5 million metric tons of CO&lt;sub&gt;2&lt;/sub&gt; emitted per day. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This &lt;em&gt;suggests&lt;/em&gt; that in 2018, the total amount of CO&lt;sub&gt;2&lt;/sub&gt; emitted by wildfires in California &lt;em&gt;might&lt;/em&gt; be in the 40 to 50 million metric ton range, or a sizeable portion of California's overall greenhouse gas emissions at around 10 percent. However, this is just a back-of-the-envelope guesstimate (my assumption: 40 to 50 days of major wildfires, at one million metric tons of CO&lt;sub&gt;2&lt;/sub&gt; equivalent per day), which may be completely flawed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any &lt;em&gt;reliable&lt;/em&gt; (or at minimum, more carefully reasoned) estimates for CO&lt;sub&gt;2&lt;/sub&gt; emissions from California wildfires, in metric tons per annum? Useful numbers would be estimates for 2018, some other recent year, or for an average year.&lt;/p&gt;&#xA;" OwnerUserId="5255" LastEditorUserId="5255" LastEditDate="2018-11-14T21:57:46.043" LastActivityDate="2020-03-05T12:24:36.033" Title="Greenhouse gas emissions from wildfires in California" Tags="|co2|greenhouse-gases|california|emissions|" AnswerCount="1" CommentCount="13" ContentLicense="CC BY-SA 4.0" />
  <row Id="15564" PostTypeId="1" CreationDate="2018-11-13T19:27:11.447" Score="3" ViewCount="1129" Body="&lt;p&gt;The Benagil caves are really impressive. How are they formed though? What makes that perfect domed shape and how is that hole in the ceiling created?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/APkCA.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/APkCA.jpg&quot; alt=&quot;Benagil sea cave, photo by Bruno Carlos&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14284" LastActivityDate="2018-11-14T11:57:40.420" Title="How are Benagil caves formed?" Tags="|cavern|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15566" PostTypeId="1" AcceptedAnswerId="15586" CreationDate="2018-11-14T04:17:40.023" Score="5" ViewCount="415" Body="&lt;p&gt;I saw the image below used as a click-attractor to an unrelated story about tourism, but found a larger version &lt;a href=&quot;http://thedailyripple.org/index.php/rss-world/340064-not-disneyland-dutch-hit-back-at-over-tourism&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Contrails, or water condensation trails happen when planes pass through the atmosphere under certain atmospheric conditions, presumably related mostly to humidity, pressure, and temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I wanted to write a contrail predictor script that would poll public sources of atmospheric data and check locations (and altitudes) to see if they were &lt;em&gt;currently substantially more prone to contrail formation now than on an average day&lt;/em&gt;, what public sources of data might I look at, and what parameters would be the most important?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Actual formation also requires air traffic of course, but that's askable on a different SE site.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FQQVE.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FQQVE.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://thedailyripple.org/index.php/rss-world/340064-not-disneyland-dutch-hit-back-at-over-tourism&quot; rel=&quot;noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2018-11-14T05:02:04.523" LastActivityDate="2018-12-07T03:14:53.397" Title="How to predict when contrails are likely to form over a specific location using public data?" Tags="|atmosphere|temperature|humidity|atmospheric-optics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15570" PostTypeId="2" ParentId="15564" CreationDate="2018-11-14T11:57:40.420" Score="1" Body="&lt;p&gt;How are they formed? Erosion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Long version: The rock/cliff the cave is set in possesses different hard/softness. Some parts of it are more prone to erosion than others.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Erosion comes in the form of waves and tides, washing and battering at the base of the cliff, nibbling away the soft parts of the rock quicker. Some chunks break off, rolling in the turf, bashing away at the cliff even more. Cracks form, get washed out and bigger and finally the cave forms. As is gets deeper and larger, rainwater might drip through the roof, adding to the erosion effects. Chunks to the roof start to fall down, and finally a part of the roof collapses. Your cave now has a hole to the sky.&lt;/p&gt;&#xA;" OwnerUserId="14194" LastActivityDate="2018-11-14T11:57:40.420" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15572" PostTypeId="1" CreationDate="2018-11-14T15:48:47.530" Score="0" ViewCount="100" Body="&lt;p&gt;How can we determine supplemental irrigation needed to reduce soil salinity knowing ETP of a crop and the annual precipitation? &lt;/p&gt;&#xA;" OwnerUserId="14297" LastActivityDate="2019-12-26T06:01:30.227" Title="Leaching Requirement" Tags="|soil|soil-science|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15576" PostTypeId="2" ParentId="15558" CreationDate="2018-11-15T14:52:57.233" Score="2" Body="&lt;p&gt;SEG-D is an uncommon format. From my experience, here is how you need to approach this problem. You can't easily jump straight from SEG-D to SU. I've had extensive experience with SU and the best methodology is to first take your current seismic data type (SEG-D) and convert to SEG-Y. Only after converting to SEG-Y format can you then jump to SU. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, here is an outline and workflow of a solution:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;1.) Download and use this tool for SEG-D to SEG-Y format: &lt;a href=&quot;http://users.chariot.net.au/~witek/segd2segy.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://users.chariot.net.au/~witek/segd2segy.htm&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;2.) Now that you have all your SEG-D data converted to SEG-Y data, use the following BASH  script to convert a single SEG-Y file to SU:&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;#!/bin/bash&#xA;echo Provide Input File: ;&#xA;read sdata;&#xA;segyread tape=&lt;span class=&quot;math-container&quot;&gt;${sdata} verbose=1 endian=0 segyclean &amp;gt; $&lt;/span&gt;{sdata}.su&#xA;echo &quot;New File: ${sdata}.su&quot;;&#xA;rm -rf binary header;&#xA;echo Done.;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;***Keep in mind that - based on the type of machine you have - endian may need to be set to 1.&lt;/p&gt;&#xA;" OwnerUserId="8447" LastEditorUserId="12155" LastEditDate="2018-11-17T17:01:35.610" LastActivityDate="2018-11-17T17:01:35.610" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15579" PostTypeId="2" ParentId="15563" CreationDate="2018-11-15T18:23:46.610" Score="2" Body="&lt;p&gt;The California Air Resources board posted &lt;a href=&quot;https://www.arb.ca.gov/cc/inventory/pubs/ca_wildfire_preliminary_co2_emissions_estimates.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this PDF&lt;/a&gt; that includes emission estimates up to 2017, which were 37.1 million metric tons. If anyone is interested in related info, the search phrase I used was, &quot;CO&lt;sub&gt;2&lt;/sub&gt; estimates for california wildfires&quot;.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastEditorUserId="2470" LastEditDate="2020-03-05T12:24:36.033" LastActivityDate="2020-03-05T12:24:36.033" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15580" PostTypeId="1" CreationDate="2018-11-15T22:24:22.330" Score="1" ViewCount="58" Body="&lt;p&gt;In my college we have to start our thesis in the third semester, so I'm going  to do a research about forest fire and its prevention. However, I'm struggling to find a article that talks about that specifically. All that I can find is people talking about how important is to have good soil and vegetation, which is really vague.&lt;/p&gt;&#xA;" OwnerUserId="14310" LastActivityDate="2020-09-05T01:46:34.577" Title="Does anyone know a book/article/research that talks about forest fire prevention?" Tags="|planetary-science|forest|ecology|vegetation|fire|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15581" PostTypeId="2" ParentId="15580" CreationDate="2018-11-16T08:19:15.427" Score="3" Body="&lt;p&gt;This book is based on Australian experience, some of it may be relevant of North American wildfires. I read it ten years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Paul Collins, &lt;em&gt;Burn - The Epic Story of Bushfire in Australia&lt;/em&gt;, Allen &amp;amp; Unwin, 2006, ISBN 9781741750539, ISBN 1 74175 053 9.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Part 4, titled: The Great Fire Debates, has three chapters (9 to 11);&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt; 09 To burn or not to burn&#xA; 10 Fire thugs&#xA; 11 Fireproofing Australia.&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Contact for Allen &amp;amp; Unwin:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;83 Alexander Street&#xA;CROWS NEST NSW 2065&#xA;Australia&#xA;&#xA;Telephone: + 61 2 8425 0100&#xA;Fax: +  61 2 9906 2218&#xA;Email: info@allenandunwin.com&#xA;Web: [www.allenandunwin.com][1]&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Another book you may want to try is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Stephen J. Pyne, &lt;em&gt;Burning Bush - A Fire History of Australia&lt;/em&gt;, University of Washington Press, Seattle &amp;amp; London, 1998.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also published by Henry Holt &amp;amp; Company, New York, 1991&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As part of his &quot;Cycle of Fire&quot; suite of books, the same author has written books, titled:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;em&gt;Vestal Fire: An Environmental History, Told through Fire, of Europe and Europe's Encounter with the World&lt;/em&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;em&gt;Fire in America: A Cultural History of Wildland and Rural Fire&lt;/em&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;em&gt;World Fire: The Culture of Fire on Earth&lt;/em&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.csiro.au/en/Research/Environment/Extreme-Events/Bushfire/Bushfire-research&quot; rel=&quot;nofollow noreferrer&quot;&gt;CSIRO&lt;/a&gt; (Commonwealth Scientific &amp;amp; Industry Research Organisation) in Australia, used to have two departments that researched bushfires/wildfires:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;CSIRO Division of Forest Research Library&lt;/li&gt;&#xA;&lt;li&gt;CSIRO National Bushfire Research Unit&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Stephen J. Pyne mentions them in his book. You might be able to get access to the results of research carried out by the CSIRO.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just be mindful of the different terminologies used in different countries to describe the same thing: bushfires in Australia and wildfires in North America.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2018-11-16T13:49:56.520" LastActivityDate="2018-11-16T13:49:56.520" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15582" PostTypeId="1" AcceptedAnswerId="15587" CreationDate="2018-11-16T15:06:02.333" Score="3" ViewCount="195" Body="&lt;p&gt;I just got the curiosity today to know whether the gems that produce electricity non stop without an end exist, and I have found &lt;a href=&quot;https://www.classicgems.net/info_pyroelectric-gems.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; site. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I’m having doubts about it, thinking that it could be fake or true, and I need to know what’s you’re opinion regarding this. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oh and, can the costumer order these types of gems as something for collection? I yes, can you share a link where to drive me to a site where I can order one of these gems? &lt;/p&gt;&#xA;" OwnerUserId="11917" LastEditorUserId="11917" LastEditDate="2018-11-16T16:05:50.863" LastActivityDate="2018-11-17T09:03:41.643" Title="Do Pyroelectric gemstones really exist? Can they be found on web market?" Tags="|mineralogy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15584" PostTypeId="1" CreationDate="2018-11-16T18:19:42.280" Score="2" ViewCount="426" Body="&lt;p&gt;For example in the Philippine Sea Plate the West Marianas Ridge has formed due to diffuse rifting in the south of the Marianas trough.  What does it mean?&lt;/p&gt;&#xA;" OwnerUserId="14240" LastEditorUserId="6298" LastEditDate="2018-11-16T21:09:25.643" LastActivityDate="2018-11-20T15:05:41.277" Title="What is diffuse plate rifting?" Tags="|geology|plate-tectonics|tectonics|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15586" PostTypeId="2" ParentId="15566" CreationDate="2018-11-17T02:02:08.703" Score="5" Body="&lt;p&gt;As described &lt;a href=&quot;http://cimss.ssec.wisc.edu/wxwise/contrail.html&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;, condensation of cloud particles (i.e., contrail formation) will occur if the mixing between hot and moist exhaust from an aircraft engine and ambient environmental air results in the mixed air exceeding the ice saturation vapor pressure as its temperature changes. A conceptual diagram of this mixing process is shown here, for exhaust (parcel A) and environmental air (parcel B) with generic temperatures and saturation vapor pressures is shown here: &lt;a href=&quot;https://i.stack.imgur.com/YdYry.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YdYry.gif&quot; alt=&quot;diagram of ice saturation vapor pressure with respect to temperature for two air parcels&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this would require knowledge of these specific temperatures and corresponding saturation vapor pressures. More practically, contrail prediction often just assumes that the air at altitudes where jets typically cruise (&lt;a href=&quot;https://web.archive.org/web/20160408184845/http://science-edu.larc.nasa.gov/contrail-edu/faq.php&quot; rel=&quot;noreferrer&quot;&gt;commonly, though not always, above 8 km/26,000 ft and at air temperatures below -40°C&lt;/a&gt;) is near or above supersaturation with respect to ice. This assumption is used operationally, for example, in &lt;a href=&quot;https://cloudsway2.larc.nasa.gov/cgi-bin/site/showdoc?mnemonic=CONTRAIL_FORECAST&quot; rel=&quot;noreferrer&quot;&gt;NASA's publicly-available persistent contrail forecast&lt;/a&gt;. Note that the first source indicates that low wind speeds are also useful in identifying likely regions of persistent contrails.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Several sources of data may be useful in constructing similar analyses or forecasts and comparing to what might be expected on an average day, based on the local climatology. Observational data from radiosondes (i.e., weather balloons with instruments measuring temperature, moisture, and winds) &lt;a href=&quot;http://weather.uwyo.edu/upperair/sounding.html&quot; rel=&quot;noreferrer&quot;&gt;is available globally in near-real time&lt;/a&gt;. This provides actual measurements of weather conditions through the relevant altitudes for contrail formation, and is particularly useful if measurements are needed relatively close to a radiosonde launch site.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For broader coverage in both space and time, the US National Oceanic and Atmospheric Administration provides &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/model-data&quot; rel=&quot;noreferrer&quot;&gt;archives of past weather analyses and operational forecast model output&lt;/a&gt; that can be requested by the general public. These datasets contain gridded model output with common parameters at various levels through the atmosphere on a national to global scale. While these datasets do not strictly consist of observed measurements, they are useful for analyses extending beyond the relatively limited set of observations available in most circumstances. Output from various operational forecast models is available for near-current or future conditions, whereas the &lt;em&gt;reanalysis&lt;/em&gt; datasets provide similar information obtained from model analyses of past weather.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a given location, the reanalysis datasets can be used to identify climatological temperature, moisture, or wind characteristics for a given location and date or season. Information from radiosondes or model forecasts can then be used to identify how conditions at a near-current (or future) time compare to these &quot;average&quot; conditions.&lt;/p&gt;&#xA;" OwnerUserId="14078" LastActivityDate="2018-11-17T02:02:08.703" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15587" PostTypeId="2" ParentId="15582" CreationDate="2018-11-17T09:03:41.643" Score="4" Body="&lt;p&gt;Yes, pyroelectric gems exist. No, they don't produce electricity all the time. Pyroelectric gems can generate a certain amount of electric potential when cooled or heated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To cite Wikipedia &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The change in temperature modifies the positions of the atoms slightly within the crystal structure, such that the polarization of the material changes. This polarization change gives rise to a voltage across the crystal. If the temperature stays constant at its new value, the pyroelectric voltage gradually disappears due to leakage current (the leakage can be due to electrons moving through the crystal, ions moving through the air, or current leaking through a voltmeter attached across the crystal)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.handbookofmineralogy.org/search.html?p=piezo_pyro&quot; rel=&quot;nofollow noreferrer&quot;&gt;A full list of all piezoelectric minerals can be found at the website of the Mineralogical Society of America&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And yes, you can buy them. Some, like Axinite, were used to remove hair and lint from objects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's no site like www.buypiezoelectricgems.com... So you should google them one by one and look for sellers. Or go to a gem fair.&lt;/p&gt;&#xA;" OwnerUserId="13398" LastActivityDate="2018-11-17T09:03:41.643" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="15589" PostTypeId="2" ParentId="2468" CreationDate="2018-11-17T20:54:55.597" Score="-2" Body="&lt;p&gt;i think that we simply do not have enough data on earth what would happen. and if such a task were even possible. as depicted by the movie The Core, there could be a crystallized structure between the core and the surface thats even impossible to dig through by conventional means. it would sound logical, given that there simply is that much pressure going on to make crystals, that an entire part of earth is made out of crystal. plus the constant shift of the earth's plates would also mean that the tunnel dug behind you would be closed off immediatly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;right now, the diagram shown above is still pure guess work. same as how the sun works, how black holes are working. we know how a bird flies and how to make electricity because we can experience it. but we havnt experienced going to the center of the earth, so we dont know yet how it works.&lt;/p&gt;&#xA;" OwnerUserId="14321" LastActivityDate="2018-11-17T20:54:55.597" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15590" PostTypeId="1" CreationDate="2018-11-18T14:56:44.933" Score="4" ViewCount="90" Body="&lt;p&gt;I've anecdotally but repeatedly observed a certain balance between temperatures in the two hemispheres. For example, early this year (2018), while Europe was under a late winter spell, weather here in Chile was a bit warmer than usual. Then, during this year's record temperatures in the northern hemisphere, the winter here appeared colder than normal. And just now, as temperatures are quickly plummeting in Europe, on cue central Chile is seeing a heat wave.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is my impression that unusual temperatures on one hemisphere are often accompanied by opposite events on the other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it possible that there is an overall energy equilibrium reflected by global temperatures?&lt;/p&gt;&#xA;" OwnerUserId="14326" OwnerDisplayName="Someone" LastActivityDate="2018-11-27T14:32:12.903" Title="Are global temperatures, specifically between the two hemispheres, in balance?" Tags="|meteorology|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15591" PostTypeId="2" ParentId="12635" CreationDate="2018-11-18T17:33:57.707" Score="1" Body="&lt;p&gt;I believe you are referring to - as @ye-ti-800 has already pointed out - the apparent stretch that results from the NMO correction applied to CMP gathers. There is a great tutorial supplied by a Leading Edge article that may be accessed here: &lt;a href=&quot;https://wiki.seg.org/wiki/Step-by-step_NMO_correction&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://wiki.seg.org/wiki/Step-by-step_NMO_correction&lt;/a&gt;. It is important to note, though, that the article does not go into details about stretch &lt;strong&gt;mute&lt;/strong&gt;. The article just goes into the specific details of the &quot;mechanics&quot; occurring during a conventional NMO correction and accompanied stretch that results from it.&lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2018-11-18T17:33:57.707" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15592" PostTypeId="1" AcceptedAnswerId="15595" CreationDate="2018-11-18T18:15:05.157" Score="1" ViewCount="95" Body="&lt;p&gt;Does a big data provider (Like a Bloomberg, which is the world's leading financial data provider) exist which includes &lt;strong&gt;ALL&lt;/strong&gt; the possible informations and parameters about climate change or in general about environment?&lt;/p&gt;&#xA;" OwnerUserId="14327" LastActivityDate="2018-11-19T07:45:40.577" Title="Does a climate change big data provider exist?" Tags="|climate-change|data-analysis|" AnswerCount="1" CommentCount="7" ClosedDate="2018-11-21T18:48:38.970" ContentLicense="CC BY-SA 4.0" />
  <row Id="15594" PostTypeId="1" CreationDate="2018-11-19T01:37:52.320" Score="1" ViewCount="50" Body="&lt;p&gt;I've been tasked with generating synthetic streamflow scenarios through disaggregation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, I will generate 50 years of streamflow data. For that, I will probably use a simple model as AR(1) or an ARMA(1,1) and am adopting some probabilistic parameters based on streamflow data I have. These data come from the historical record a gauge station.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From my yearly flow, I have to generate monthly streamflows. In the end, instead of 50 streamflow realizations, each one representing an annual flow; I'll have 600 streamflow realizations, each representing a monthly stream flow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, to get from annual to monthly stream flow, I will need a correlation matrix.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I could simply estimate the monthly correlation from January to December by calculating the correlation among monthly streamflows from a set of historical streamflow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One could say that the physical aspects involving the (auto)correlation are implicit in the data itself. However, the data I have for this gauge station - as for any other - is only one realization of the stochastic process from which the observed streamflows were generated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How, then, could I enrich this monthly (auto)correlation with physical concepts stemming from the river where the gauge station is located? I should add that my question also applies to cross-correlation between two different time-series. How, in that case, could I enrich the cross-correlation matrix employing physical aspects between 2 observed time-series?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="5301" LastActivityDate="2018-11-29T14:10:31.030" Title="How to obtain the correlation between monthly streamflows based on physical concepts?" Tags="|hydrology|correlation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15595" PostTypeId="2" ParentId="15592" CreationDate="2018-11-19T07:39:44.263" Score="0" Body="&lt;p&gt;I happened to catch a 60 minutes &lt;a href=&quot;https://www.cbsnews.com/news/michael-bloomberg-net-worth-is-47b-how-will-he-use-it/&quot; rel=&quot;nofollow noreferrer&quot;&gt;interview piece on Bloomberg&lt;/a&gt;... while the interview was honestly more adulation than journalism, they showed a little bit about the Bloomberg Terminal at times which really caught my eye.  (&lt;a href=&quot;https://www.cbsnews.com/news/michael-bloomberg-net-worth-is-47b-how-will-he-use-it/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The transcript&lt;/a&gt; has a few details, but the video would hopefully be more thorough... looks like you can watch the full interview &lt;a href=&quot;https://www.cbs.com/shows/60_minutes/video/ulLlK3UFLU4r9kep_SHY8B0sUHcxshUe/bloomberg/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; if you happen to have the pay CBS All Access service).  It really seemed like it was a remarkable tool at gathering diverse data together into sort of like a master dashboard or real-time encyclopedia, and making it very flexible and easily consumable.  It seems to be something that could be of amazing use, and I suggest folks look into to get an idea of what can be done with technology applied well, it may spark some creativity and reshape views.  Knowing what that software is about, the questions seems a very valid one, as I'd always be eagerly on the look out for such a comprehensive and thorough collection of unified data on the topic of climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But that said, I'm quite sure the answer is a firm &lt;strong&gt;no&lt;/strong&gt;; such a comprehensive source of climate data likely doesn't exist.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bloomberg has really done what they've done because the information they're collecting is worth huge value in the markets, and they can then sell that utility for great prices.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But there's likely not such money in most other topics, including much of scientific data.  If there were such tools developed in science, one would think they may well focus more on aggregating and simplifying subjects that are clearly more lucrative, such as genetic data, or detailed medical records, or, if venturing nearer our fields here, oil/mineral data, or perhaps maybe meteorological data, rather than climate data and one particular prong of it (how it is changing/why).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, there's a lot of attention in climate change these days, and so research may well be funded a bit more than it used to be.  But the focus in the study is still really on developing conclusions to convince the public and policy makers, rather than on generating some tangible asset/information that owners could practically apply to thereby excel in some lucrative market field.  While there are indeed some industries with significant connection to the topic, such as energy generation and pollution credits, their focus is generally on gathering the very specific information they need (e.g., wind/solar data/modeling for renewable energy siting, forecasting politics for predicting policy shifts in generation balance and pollution controls, etc).  I've not known anyone to forsee any giant particular financial use of drawing all the climate change data together.  [Then again I wouldn't have imagined that a group like Bloomberg's would have recognized the potential and then had such technological vision and success in culling such wide-ranging access to make something like there tool... until I saw the story)  But it just doesn't seem there are the obvious grand benefits to doing similar for climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The closest I can think of would be &lt;a href=&quot;https://www.zdnet.com/article/ibms-new-launch-pairs-geoscope-aims-to-be-search-for-geospatial-big-data/&quot; rel=&quot;nofollow noreferrer&quot;&gt;IBM's initiative towards meteorological big data&lt;/a&gt;.  Others sites like NOAA's &lt;a href=&quot;https://www.ncdc.noaa.gov/cdo-web/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate Data Online&lt;/a&gt; have a few items, and &lt;a href=&quot;https://discuss.okfn.org/t/climate-change-datasets/1593/4&quot; rel=&quot;nofollow noreferrer&quot;&gt;this open data collection&lt;/a&gt; appears it may also offer a good starting point.  But overall, it may well more often still come down to tracking down separate specific datasets yourself when getting into more of the specifics.  Of course you're in a good place here to try asking if you decide there's something specific you're after!&lt;br&gt;&#xA;But in terms of company by company data, I expect being related to corporate affairs, there's more hope in finding that using Bloomberg itself than in finding another such source built around this specific subject.  There likely are websites that monitor news stories and such.  And there may be at least some separate piecemeal datasets findable on specific impacts to people/countries/industries/etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've indeed found it frustrating for years that even as piles of articles and webpages have been made focusing on climate change, there really still aren't fantastic options that allow typical folks and experts in other subjects to quickly and easily explore the past and current data very flexibly and graphically, more in line with it appears Bloomberg's software is.  Yes, it's still possible for even novices to dig in with enough work, as even &lt;a href=&quot;https://earthscience.stackexchange.com/questions/15039/how-to-best-visualize-temperature-increase-due-to-climate-change-using-ghcn-da&quot;&gt;this question&lt;/a&gt; here at ESSE did a great job of.  But we have miles to go of improvement in such true accessibility.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do hope if you unfortunately have to go through the painstaking effort to source and gather such data, that you'll take the time to give back as you're able, to help others who come after you!  We really only do advance anywhere by the progress of those who came before us.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Best of luck, and hope the input was at least of some help to you or others somewhere along the way at least.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2018-11-19T07:45:40.577" LastActivityDate="2018-11-19T07:45:40.577" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15599" PostTypeId="1" AcceptedAnswerId="15603" CreationDate="2018-11-20T01:33:49.167" Score="2" ViewCount="330" Body="&lt;p&gt;Forever I have seen little shops here and there offer minerals like those crystals and neat shaped rocks of different kinds, turquoise and amethyst and many others and such. But I never really thought about it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In looking a bit it doesn't seem there is a Home Depot for minerals. That is, there's no giant store that offers tons of minerals of every kind in vast quantities. The biggest collection of minerals I ever saw was &lt;a href=&quot;https://nhm.org/site/explore-exhibits/permanent-exhibits/gems-minerals&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/F9Hax.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/F9Hax.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All of those tiny fist-sized samples are probably pretty much different types of minerals. So then to scale that to buckets or bins and tractors full of each type, I have never seen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So it seems that these small shops get the minerals in small quantities from somewhere &lt;em&gt;other than&lt;/em&gt; a Home-Depot--like place. That's what I'm wondering about (the first part of the question), where they get the minerals from. I have heard that these people actually go out &lt;a href=&quot;https://en.wikipedia.org/wiki/Mineral_collecting&quot; rel=&quot;nofollow noreferrer&quot;&gt;rock hunting&lt;/a&gt; and find them themselves. I am not wondering where &lt;em&gt;specifically&lt;/em&gt; they go and find each different type (I have no specific minerals I am interested in), just generally wondering if they are actually going out into the fields with a chisel and a brush and digging stuff up, putting them in their pockets, and then taking them home and cleaning them up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If that's not the case, I wonder what they actually do to get them (at a high level).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If that &lt;em&gt;is&lt;/em&gt; the case, then I am wondering how they actually (a) know where to look, and (b) are allowed to do that. To narrow this down, it sounds like there are a few scenarios:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;There is just public land and you start looking without any mines or anything.&lt;/li&gt;&#xA;&lt;li&gt;There is private land and you start looking without any mines or anything.&lt;/li&gt;&#xA;&lt;li&gt;You go to a mine and somehow get permission to look around in the field.&lt;/li&gt;&#xA;&lt;li&gt;Then my thoughts. Perhaps the &quot;company&quot; miners (or whoever is actually doing the main mine operation) is mining for rock A, and there are pockets of rock or mineral B scattered around, which would just go to waste. So the mineral collector asks to go through the &quot;rock waste&quot; and gets the minerals that way. That seems like the best way to get it in bulk.&lt;/li&gt;&#xA;&lt;li&gt;You have direct access to the mine and the mine is for the specific mineral(s), so you are getting it in big chunks.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;What I am wondering is this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Who does 1-5. Wondering if most of the time (sort of thing) hobbyists do 1 and 2, and maybe if they are adventurous 3 or 4, while the &quot;shops&quot; do 5. The shops own the land and own the mine. Wondering generally (just a quick note) on what the behavior is like in looking for the rocks, if most of the time it's just browsing the field in broad areas, or no, you know exactly where you're going by checking with some expert nearby and are going to harvest a specific type of mineral.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am also wondering how much work it takes to find stuff, and how to get permission to the mine, but those I might save for future questions, unless it's just a casual &quot;just ask them and be nice&quot; sort of thing :).&lt;/p&gt;&#xA;" OwnerUserId="784" LastEditorUserId="784" LastEditDate="2018-11-20T01:40:04.037" LastActivityDate="2018-11-21T15:52:09.020" Title="Where/how people find minerals" Tags="|mineralogy|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15601" PostTypeId="2" ParentId="15584" CreationDate="2018-11-20T13:27:00.080" Score="1" Body="&lt;p&gt;If memory serves rifting is defined as either discrete or diffuse. Discrete rifting means that the crust is coming apart in one narrow area, usually in the form of a single defined split in the crust such as at divergent plate boundaries. Diffuse rifting is often seen in backarc spreading and involves many small localised extensional breaks in the crust, each break is small but with multiple breaks spread over a large area the total extension can be quite large. For example discrete rifting can be looked at as a 2 metre break along a single axis while a zone of diffuse rifting would involve several 1 metre breaks each with its own axis, all of which are parallel to each other and perpendicular to the direction of rifting.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="10735" LastEditDate="2018-11-20T15:05:41.277" LastActivityDate="2018-11-20T15:05:41.277" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15602" PostTypeId="1" AcceptedAnswerId="15623" CreationDate="2018-11-20T16:17:37.323" Score="3" ViewCount="170" Body="&lt;p&gt;I am going through &lt;em&gt;An Introduction to Applied and Environmental Geophysics&lt;/em&gt;, a book by &lt;em&gt;John Reynolds&lt;/em&gt; (2011), to better understand radiometrics and gamma-ray spectrometry. The author provides some tables about decaying as well as a plot of airborne gamma-ray spectrometry data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Table 15.2A shows the Uranium decay series, while Table 15.2C shows the Thorium decay series. The plot shows the survey result of an airborne gamma-ray spectrometry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As one can see in the plot, the author relates &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the Potassium series with peak at 1,46 MeV with corresponding element &lt;sup&gt;40&lt;/sup&gt;K&lt;/li&gt;&#xA;&lt;li&gt;the Uranium series (shown in Table 15.2A) with peak at 1,76 MeV with corresponding element &lt;sup&gt;214&lt;/sup&gt;Bi&lt;/li&gt;&#xA;&lt;li&gt;the Thorium series (shown in Table 15.2C) with peak at 2,82 MeV with corresponding element &lt;sup&gt;208&lt;/sup&gt;Tl&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The problem is: for both Uranium and Thorium decay series shown, the decay values presented at the tables differ from the peaks at the plot. I would expect to see the Uranium series peak with a value of 3.272 MeV (&lt;sup&gt;214&lt;/sup&gt;Bi decay value in Table 15.2A) instead of 1,76 MeV shown in the plot.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same for Thorium series: if the corresponding decay energy of &lt;sup&gt;208&lt;/sup&gt;Tl is 5.001 MeV accordingly to Table 15.2C, why does the plot show a corresponding value of 2.82 MeV?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MyyRr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MyyRr.jpg&quot; alt=&quot;Uranium decay series&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/nRzCo.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nRzCo.jpg&quot; alt=&quot;Thorium decay series&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/yNEIp.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yNEIp.jpg&quot; alt=&quot;airborne gamma-ray spectrometry&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14280" LastActivityDate="2018-11-26T10:40:11.683" Title="gamma-ray spectrum vs energy decay" Tags="|geophysics|radioactivity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15603" PostTypeId="2" ParentId="15599" CreationDate="2018-11-20T16:44:40.637" Score="4" Body="&lt;p&gt;In the United States, mining minerals is similar to mining for precious metals (for the most part). You can establish a mining claim on a likely spot of Federal/State land and go to town. There are rules and regulations that guide the appropriate ways to establish, work and maintain a claim. You can also negotiate with a private land-owner for rights to mine on their land.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One step up is wholesale markets that sell mineral specimens (and all the items that go with them). There is a &lt;a href=&quot;http://www.tgms.org/show/&quot; rel=&quot;nofollow noreferrer&quot;&gt;huge one&lt;/a&gt; in Tucson AZ in Jan/Feb with an amazing spectrum of stuff.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These markets are where most small retailers go to get their product.&lt;/p&gt;&#xA;" OwnerUserId="10936" LastEditorUserId="10936" LastEditDate="2018-11-21T15:52:09.020" LastActivityDate="2018-11-21T15:52:09.020" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15606" PostTypeId="2" ParentId="10128" CreationDate="2018-11-20T23:50:53.143" Score="0" Body="&lt;p&gt;It seems like you use a tube of sufficient volume that the effects of the interior walls are de minimus on the air in the tube, and long enough for there to be some temperature gradient top to bottom.  Then you need a &quot;piston&quot; made of wire mess of a material with high emissivity.   The wire mesh is so that the piston has de minimus effect on convection.  Finally you need a hot plate at the bottom that produces a known amount of radiation and  thermometer close to the plate to monitor temperature.   Then you measure the temperate with &quot;no piston&quot; in the tube, and compare with the piston in the tube at various distances from the plate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems this would enable one to prove/disprove back-radition.&lt;/p&gt;&#xA;" OwnerUserId="14341" LastActivityDate="2018-11-20T23:50:53.143" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15609" PostTypeId="1" AcceptedAnswerId="15611" CreationDate="2018-11-22T01:36:20.193" Score="4" ViewCount="111" Body="&lt;p&gt;We've learnt in science at school that &quot;Mafic&quot; lava forms rocks with 45% to 55% silica, meanwhile &quot;Felsic&quot; lava forms rocks with &gt;=65% silica. So what is lava called in between? Or is it impossible for any lava to cool into rocks with that range of silica? Why?&lt;/p&gt;&#xA;" OwnerUserId="14349" LastActivityDate="2018-11-22T09:56:27.950" Title="What is lava called if it has 56% to 64% silica?" Tags="|volcanology|igneous|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15610" PostTypeId="1" CreationDate="2018-11-22T09:50:07.423" Score="5" ViewCount="61" Body="&lt;p&gt;In today's world the presence of ozone in the stratosphere is the reason for the stratospheric temperature inversion which keeps a lid on the troposphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But before the Great Oxygenation Event there wouldn't have been enough oxygen to create ozone in the stratosphere. Which leads two questions&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Would the top of the troposphere have been much higher?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) If there's no stratosphere to keep wet air down in the troposphere would more water have got into the upper atmosphere where it can be dissociated by UV light and the hydrogen lost into space?&lt;/p&gt;&#xA;" OwnerUserId="14354" LastActivityDate="2018-11-22T09:50:07.423" Title="Would there have been a stratosphere in the Archean before the Great Oxygenation Event?" Tags="|ozone|great-oxidation-event|stratosphere|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15611" PostTypeId="2" ParentId="15609" CreationDate="2018-11-22T09:56:27.950" Score="6" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;What is lava called if it has 56% to 64% silica?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It's called &lt;a href=&quot;https://duckduckgo.com/?q=igneous%20classification&amp;amp;ia=images&amp;amp;iax=images&quot; rel=&quot;noreferrer&quot;&gt;intermediate&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Or is it impossible for any lava to cool into rocks with that range of silica?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not impossible, but not common. The two most common lava types are indeed mafic (mostly basalts) and felsic (mostly rhyolite). A well known intermediate lava type is andesite.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Why?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This question of why most lavas are either mafic or felsic has been bothering geologists for a very long time. This problem even has a name: the &quot;Daly gap&quot;, named after the geologist who first identified the problem almost 100 years ago. There is no easy answer, and it's still being debated. A good (yet somewhat technical) read is available here in this &lt;a href=&quot;https://www.researchgate.net/post/The_Daly_Gap_where_are_the_missing_andesites&quot; rel=&quot;noreferrer&quot;&gt;ResearchGate question and following answers&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-11-22T09:56:27.950" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15614" PostTypeId="2" ParentId="7526" CreationDate="2018-11-23T07:29:32.197" Score="4" Body="&lt;p&gt;I think it is best to introduce some definitions. Often in such studies, two types of evapotranspiration (or evaporation, but I will stick to evapotranspiration during this answer for convenience) are defined: actual and potential evapotranspiration:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/JpK1f.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JpK1f.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sub&gt;&lt;sup&gt;Source: presentation called &lt;a href=&quot;https://www.slideshare.net/jannatiftikhar/evapotranspiration-71111011&quot; rel=&quot;nofollow noreferrer&quot;&gt;Water resources and their management in Pakistan by Jannat Iftikhar&lt;/a&gt;&lt;/sup&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you have already stated correctly: when vegetation is present, the surface (generally) holds more water, hence more water is lost to the atmosphere. While barren land experiences more heating and stronger winds, the barren land tends to hold less water to evaporate. Consequently, even though the conditions allow faster and more severe evapotranspiration, there is just no water to evapotranspirate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The figure below shows an excellent example of this principle for two catchments in Saskatoon. Even though this figure isn't about an area facing desertification, it does exemplify the principle explained above.&lt;br&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/84Iff.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/84Iff.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;sub&gt;&lt;sup&gt;Source: An Overview of Temporary Stream Hydrology in Canada (&lt;a href=&quot;https://www.researchgate.net/publication/235048220_An_Overview_of_Temporary_Stream_Hydrology_in_Canada&quot; rel=&quot;nofollow noreferrer&quot;&gt;Buttle et al., 2012&lt;/a&gt;)&lt;/sup&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, the potential evapotranspiration is higher in summer for graph (a), whereas the actual evapotranspiration is higher in graph (b) due to its bigger stock of moisture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To specify differences with respect to desertification, studies often compare catchments of similar size, meteorological conditions (radiation, precipitation, etc) but with different types of vegetation or different amounts/coverage of vegetation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For catchments where we have a water surplus, we can check the discharge of that specific catchment and the average precipitation (which produces the discharge when multiplied by the area of the catchment). The difference between the two is the water lost to other processes of which evapotranspiration is the main one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the barren land situation, different methods are applied. One could try to calculate the energy balance of the surface based on measured or estimated meteorological and atmospheric parameters. Another option would be to place an evaporation pan, which is basically a flat surface with a layer of water. Subsequently, one can determine how much water is lost from it over a given period of time (taking into account the precipitation).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sources: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Iftikhar, J.(2017). Evapotranspiration. Water Resources &amp;amp; their Management in Pakistan. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;M Buttle, James &amp;amp; Boon, Sarah &amp;amp; Peters, Daniel &amp;amp; Spence, Christa &amp;amp; van Meerveld, Ilja &amp;amp; Whitfield, Paul. (2012). An Overview of Temporary Stream Hydrology in Canada. Canadian Water Resources Journal.&lt;/p&gt;&#xA;" OwnerUserId="13870" LastEditorUserId="6298" LastEditDate="2018-11-24T13:08:26.457" LastActivityDate="2018-11-24T13:08:26.457" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15615" PostTypeId="1" AcceptedAnswerId="15634" CreationDate="2018-11-23T07:56:17.103" Score="0" ViewCount="44" Body="&lt;p&gt;I am reposting from GIS Stack Exchange as here might also be someone who might help:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have a precipitation GRIB2 file obtained at EUMETSAT H-SAF I am able to decode it to ascii but the software I am using (gdal, ArcMap,...) does not recognize the projection (in the title) so I am not able to properly project to Web Mercator for example. &#xA;So can anyone please suggest software that preferably works on Ubuntu and projects either grib2 files to other projections or is able to recognise the projection from decoded ascii.&lt;/p&gt;&#xA;" OwnerUserId="6182" LastActivityDate="2018-11-26T10:05:48.337" Title="Projecting rectangular stereography centred on 42°N, 10°E" Tags="|meteorology|precipitation|weather-satellites|projection|coordinate-system|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="15616" PostTypeId="1" AcceptedAnswerId="15631" CreationDate="2018-11-23T17:54:33.647" Score="2" ViewCount="793" Body="&lt;p&gt;It would seem, on the face of it, improbable that the continental land-masses would accumulate into a single composite, yet it has happened numerous times, and is expected to again in the future.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There must likely then be some aspect of plate tectonics which favors these arrangements.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone provide an explanation?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT:  This is &lt;em&gt;not&lt;/em&gt;, as I see it, a duplicate of the 'What are the causes of the supercontinent cycle?' question.  This question goes to what process drives the &lt;strong&gt;formation&lt;/strong&gt; of any &amp;amp; all supercontinent formations, which I assert should be improbable, made more improbable by their recurrence, not so much the cycle itself.  The other question did not address this more fundamental aspect, or in any case receive a pertinent account of its resolution.  If anyone wants to engage on this, or doesn't see the distinction, please do so in the comments or a chat.&lt;/p&gt;&#xA;" OwnerUserId="14361" LastEditorUserId="14361" LastEditDate="2018-11-25T22:03:48.363" LastActivityDate="2018-11-26T12:18:03.203" Title="Why Do Supercontinents Form?" Tags="|geophysics|plate-tectonics|earth-history|continent|" AnswerCount="3" CommentCount="8" FavoriteCount="0" ClosedDate="2018-12-01T14:01:33.543" ContentLicense="CC BY-SA 4.0" />
  <row Id="15618" PostTypeId="1" CreationDate="2018-11-24T04:20:38.860" Score="-3" ViewCount="593" Body="&lt;p&gt;Consider this scenario: If the surface density of Earth were constant, it would follow that it would be impossible to have all land mass that is above the floor of the ocean concentrated on one side of the Earth. The water would simply flow until it centered over the mass of the earth. With this scenario the amount of land mass above the average ocean floor would need to be balanced around the sphere of the Earth, so with all of the currently above water continents on one side of the earth (Pangaea), other continent(s) would be exposed on the opposite side of the earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So is that scenario really the case, or is there actually enough density variation in Earth's crust to have higher density rock concentrated on the ocean side of Earth, which would allow all of the landmass above water to be concentrated on the less dense side?&lt;/p&gt;&#xA;" OwnerDisplayName="user14364" LastEditorDisplayName="user14364" LastEditDate="2018-11-25T14:40:31.887" LastActivityDate="2018-11-30T06:54:20.347" Title="Given that water will center over the mass of Earth, how could Pangaea be the only continent?" Tags="|continental-rifting|continent|" AnswerCount="3" CommentCount="19" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15621" PostTypeId="2" ParentId="15618" CreationDate="2018-11-24T15:46:12.113" Score="7" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Assuming that the surface density is relatively constant, it would be impossible to have all of the above water land mass concentrated on one side of the Earth.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That's a bad assumption. Four key differences between oceanic and continental crust are&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Chemical composition. The rock that forms oceanic crust has more calcium and magnesium but less aluminum and silica that does the rock that forms continental crust.&lt;/li&gt;&#xA;&lt;li&gt;Density. The different chemical compositions makes oceanic crust about 10% more dense than continental crust.&lt;/li&gt;&#xA;&lt;li&gt;Age. The oldest oceanic crust is 100 million years old while the oldest continental crust is over 4 billion years old. The processes that recycle ocean crust (primarily subduction) are much more efficient than are the processes that recycle continental crust.&lt;/li&gt;&#xA;&lt;li&gt;Thickness. The quick recycling of oceanic crust keeps it from building up. Most oceanic crust is between 7 to 10 kilometers thick. The slow recycling of continental crust has enabled it to build up over time. Most continental crust is between 25 to 70 kilometers thick.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The combination of different densities and different thicknesses means that the continents are elevated above the ocean floors by almost 5 kilometers on average.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2018-11-24T15:46:12.113" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15623" PostTypeId="2" ParentId="15602" CreationDate="2018-11-24T17:32:32.567" Score="3" Body="&lt;p&gt;I will first focus on the &lt;sup&gt;214&lt;/sup&gt;Bi decay. The 3.272 MeV is the total amount available &lt;em&gt;for the &amp;beta;&lt;sup&gt;-&lt;/sup&gt; decay&lt;/em&gt;, i.e. the difference between the ground states of &lt;sup&gt;214&lt;/sup&gt;Bi and &lt;sup&gt;214&lt;/sup&gt;Po. If you have a beta decay into the ground state of of &lt;sup&gt;214&lt;/sup&gt;Po, which happens in 19.9 % of cases (all data are from Firestone, R. B. et al., “Table of Isotopes”, 8th ed., 1998, p. 9211, in short “ToI”), there will be no gamma emission from &lt;sup&gt;214&lt;/sup&gt;Po, the 3.272 MeV are distributed between the electron and the electron antineutrino. However, in 16.9 % of cases, the decay leads to an excited state of &lt;sup&gt;214&lt;/sup&gt;Po with an energy of 1764.499 keV which can then deexcite among other possibilities by emission of a 1764.494 keV gamma photon (15.36 % of beta decays). The decay can produce a large number of gamma ray lines, but most happen with low probability. You can have a look at page 23 of this &lt;a href=&quot;http://www.nucleide.org/DDEP_WG/Nuclides/Bi-214_tables.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;sup&gt;214&lt;/sup&gt;Bi table of radionuclides extract&lt;/a&gt; to get an impression.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In summary, the 3.272 MeV get distributed in varying proportion to the electron and the electron antineutrino from the beta decay, zero or more gamma-ray photons, and some small amount to nuclear recoil, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case of &lt;sup&gt;40&lt;/sup&gt;K decaying via electron capture to &lt;sup&gt;40&lt;/sup&gt;Ar (10.72 % of cases), the total decay energy (Q-value) is 1504.9 keV. Most of the time (10.67 %), this goes to an excited state (1460.859 keV), which in turn gives rise to the 1460.830 keV gamma-ray line. The rest of the energy goes to the electron neutrino.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly, for &lt;sup&gt;208&lt;/sup&gt;Tl, the 5000.9 keV is the Q-value of the &amp;beta;&lt;sup&gt;-&lt;/sup&gt;-decay. Most of the time (48.7 %), the decay proceeds via an excited state (3197.743 keV) of &lt;sup&gt;208&lt;/sup&gt;Pb, which deexcites via another excited state (2614.551 keV) where 99 % of decays also lead. This state the deexcites via the emission of a 2614.533 keV gamma ray photon. I believe the 2.82 MeV from Fig. 15.1 is a typo, since the reference in Reynolds’ book points to the article “&lt;a href=&quot;http://www.geoexplo.com/airborne_survey_workshop_rad.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Airborne Gamma-Ray Spectrometry Surveys&lt;/a&gt;”. There Fig. 4.4-1 is the same as Fig. 15.1 from the book, but in rather low resolution and with hard-to-read numbers. The text, however discusses the 2.62 MeV gamma ray line, which is very likely a rounded value of the 2614.533 keV from the “Table of Isotopes”.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sum of the probabilities of different gamma ray lines from the same decay can be larger than 100 % if the deexcitation happens via a gamma-ray cascade, i.e. if the nucleus first transitions into an intermediate excited state and then again to the ground state or further intermediate states. This means that a single beta decay results in multiple gamma-ray emissions. This is illustrated in the Wikipedia article on &lt;a href=&quot;https://en.wikipedia.org/wiki/Gamma_ray#Decay_schemes&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gamma rays&lt;/a&gt; using the example of the &lt;sup&gt;60&lt;/sup&gt;Co decay which results in two photons emitted in &gt; 99.9 % of cases.&lt;/p&gt;&#xA;" OwnerUserId="14368" LastEditorUserId="14368" LastEditDate="2018-11-26T10:40:11.683" LastActivityDate="2018-11-26T10:40:11.683" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15626" PostTypeId="2" ParentId="15616" CreationDate="2018-11-25T03:46:48.367" Score="1" Body="&lt;p&gt;The simple answer is that when continental plates collide, they tend to stick together, until eventually all 7 are stuck together at once. Currently Eurasia, Africa, and India have already recombined. Australia will recombine relatively soon. The Americas and Antarctica still have a long way to go.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason why continents stick together has to do with the positive feedback mechanism of &quot;seafloor spreading&quot; and &quot;mantle convection&quot;. Once the continents begin to break up, the process of seafloor spreading ensures that the initially small oceans will continue to spread until there is once again a single large ocean. The driver of seafloor spreading is mantle convection, which in turn is powered by the weight of the cool, dense, subducting slabs that descend to the planet core. When the continents begin to break apart, subducting only occurs in the existing large ocean (think Mariana Trench). Once started, this subducting is difficult to stop, and it acts as a vacuum, sucking the continents toward it. Since the earth is a sphere, what goes around comes around. This supercontinent cycle takes about 300-500ma.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Seafloor_spreading&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Seafloor_spreading&lt;/a&gt; has a map of the current Age of the Oceanic Lithosphere that shows how seafloor spreading only occurs in the middle of oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Mantle_convection&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Mantle_convection&lt;/a&gt; includes a picture illustrating mantle convection.&lt;/p&gt;&#xA;" OwnerDisplayName="user14364" LastEditorUserId="14361" LastEditDate="2018-11-26T08:38:08.647" LastActivityDate="2018-11-26T08:38:08.647" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="15627" PostTypeId="2" ParentId="15572" CreationDate="2018-11-25T08:20:20.063" Score="0" Body="&lt;p&gt;A very simplistic view, assuming no runoff, is that the crop will use all the water up to its potential evapotrainspiration. So if you know the precipitation, then you need to add enough water to exceed the potential ET. The excess water will infiltrate below the root zone, carrying the salt with it. The amount of excess needed will depend on the soil type and how fast you want the salt to be leached out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But you also need to consider the seasonality of the crop vs the rainfall. If you have annual crops and winter rainfall, that can leach the salt built up over the summer. In addition, preferential flow in the soil can result in less efficient salt removal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are interested in a particular area, the farm services or agricultural extension agencies may have guidance.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2018-11-25T08:20:20.063" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15628" PostTypeId="2" ParentId="7526" CreationDate="2018-11-25T08:43:17.920" Score="3" Body="&lt;p&gt;&lt;em&gt;In general&lt;/em&gt;, evapotranspiration from vegetated areas is greater than the bare soil evaporation. You are correct that vegetation will increase the boundary layer and thus reduce evaporation at the ground surface but interception of precipitation will also mean that some of the precipitation will evaporate before it reaches the ground. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are effects of vegetation type and % ground-cover that usually reduce runoff, but that water infiltrates. Infiltration is important in increasing evapotranspiration over evaporation. The water that moves deep enough into the soil column under bare soil conditions isn't evaporated and is lost to interflow or recharge. Plant roots capture a significant amount of the infiltration so transpiration increases. The deeper the roots, the more infiltration that can be captured.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2018-11-25T08:43:17.920" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15629" PostTypeId="2" ParentId="29" CreationDate="2018-11-25T14:01:35.647" Score="2" Body="&lt;p&gt;Potential enthalpy is the better variable. TEOS-10 functions render the main work as doing the &lt;em&gt;in situ&lt;/em&gt; measurements. Fortunately, a great amount of that has already been done (&lt;a href=&quot;https://blogdredd.blogspot.com/2018/11/in-search-of-ocean-heat.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;In Search of Ocean Heat&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One converts practical salinity or conductivity into Absolute Salinity, converts temperature into Conservative Temperature, and height (-depth) into Pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then the TEOS-10 functions can be used with those variables to calculate the requisite forms of enthalpy (specific enthalpy, dynamic enthalpy, potential enthalpy).&lt;/p&gt;&#xA;" OwnerUserId="14376" LastActivityDate="2018-11-25T14:01:35.647" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15631" PostTypeId="2" ParentId="15616" CreationDate="2018-11-25T23:09:42.917" Score="1" Body="&lt;p&gt;I think the mechanisms that you're looking for are subduction, paired with the &quot;stickiness&quot; of continental crust. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The subduction of oceanic crust under continental crust inevitably creates a net movement of crustal material &lt;em&gt;toward&lt;/em&gt; a continental plate. Any oceanic plate that is carrying continental material will therefore always drag that continent toward the continental plate that it is subducting underneath, always resulting in eventual collision. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If an oceanic plate has subduction occurring on both sides, the ocean will inevitably narrow until it closes, thereby causing the continental plates on either side to collide.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In every case, subduction inevitably pulls continents together.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, once continental plates collide, they have a tendency to stick together for long periods of time, increasing the likelihood that all continental material will eventually accumulate there.&lt;/p&gt;&#xA;" OwnerUserId="14045" LastActivityDate="2018-11-25T23:09:42.917" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="15632" PostTypeId="1" CreationDate="2018-11-26T00:34:48.907" Score="3" ViewCount="1480" Body="&lt;p&gt;I am looking to analyze outside lighting data and its implications on human health regionally, but I can't seem to find a ubiquitous database that contains outside lux illumination data throughout the continental US. This is essential to my study and seems to be measurable, but virtually nonexistent on each climactic database I request from.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any help is appreciated,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerDisplayName="user14379" LastActivityDate="2019-01-10T10:01:05.210" Title="Where can I find weather data on ambient outside illumination?" Tags="|light|database|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="15634" PostTypeId="2" ParentId="15615" CreationDate="2018-11-26T10:05:48.337" Score="-1" Body="&lt;p&gt;The product (H-SAF 05) manual stated the datasets are in the projection mentioned in the title. EUMETSAT user support answered me the datasets use a polar stereographic projection with 25-75°N lat, 25°W- 45°E long.&lt;/p&gt;&#xA;" OwnerUserId="6182" LastActivityDate="2018-11-26T10:05:48.337" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15635" PostTypeId="2" ParentId="15616" CreationDate="2018-11-26T12:18:03.203" Score="4" Body="&lt;p&gt;Just to reiterate some of the points previously said here:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Continental crust fragments that collided are sticky. This results in mountain belts that essentially &quot;glue&quot; the two crusts together.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Subduction of a plate that contains both oceanic and continental crusts underneath continental crust will inevitably lead the the complete loss of the oceanic crust, and the gluing of the continental crust to the other one. India and the Himalayas are an example of something like this with all oceanic crust lost to the mantle, and the Mediterranean is an example of an almost completely subducted oceanic crust (aka the Tethys), with the formation of a mountain belt (Alps) and soon have two continental crusts glued together (Europe and Africa).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;it could also be subducting AWAY from an adjacent plate also containing continental crust&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&quot;Away&quot; on a sphere means &quot;towards&quot; in the other direction. It's all relative here.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;or at least lower the probability of all continental crust being&#xA;  annealed at one time&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They don't have to be annealed at one time. They just have to be annealed for long enough, without rifting, so all end up in one place.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;is how all these pieces land together again &amp;amp; again so improbably&#xA;  frequently&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Improbably frequently? The last one existed about 300 million years ago, and the next one will form only in about 200 millions (more or less, depending who you're asking). In geological history, there are only two confirmed supercontinents, Pangea and Rodinia. Anything earlier than that is pure speculation (although educated speculation). I wouldn't call &quot;twice&quot; in 4.5 billion years &quot;frequent&quot;.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;I can also demonstrate by example. Today, there is only one rift that is properly breaking up a continent. This is the East African rift, and the Red Sea is a nascent ocean that is spreading now. But, there are more than one collision zones. The Australian plate is moving northwards, and soon will stick to SE Asia. India is already stuck there. Asian plate is stuck to European plate (Urals in Russia are the suture zone). Arabian plate and African plate are moving northwards as well (Alps, Zagros, all those mountain belts are the suture zones). The Pacific ocean used to be a whole lot bigger (Panthalassa Ocean). One oceanic plate is already underneath North America. The subduction rate of the Pacific Plate is the fastest of all subduction zones, and in not too long ago America (particularly North) will stick to Asia. The Atlantic Ocean has no subduction zones, so it will grow to become the new Panthalassa Ocean, with most other continents forming one single supercontinent.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the break-up is of no particular relevance, and seems to be straight-forward - plate movement under the cratons&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Actually no. The &quot;cratons&quot; are already a single plate, glued together from several other plates. The break-up usually occurs because of&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;build-up of mantle heat under the insulating continental lid, will ultimately cause rifts to begin and start to form young oceanic crust (Arkenstein XII from the comments).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="725" LastActivityDate="2018-11-26T12:18:03.203" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15639" PostTypeId="2" ParentId="15445" CreationDate="2018-11-26T17:30:34.670" Score="2" Body="&lt;p&gt;Since the question was referencing an aviation weather product (links no longer functional), there is a contextual answer as well.  The aircraft dispatcher for an airline flight must plan the flight according to FAA regulations, some of which apply to weather information. Only specific sources of weather observations and forecast products are authorized, and the &quot;VALID&quot; period must also be taken into account. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I'm planning a flight that will depart at 1400Z and arrive at 1755Z, I am not authorized to use a forecast product that was issued at 00Z and is valid at 1800Z.  Even though this forecast product was issued prior to me starting to plan the flight, and thus is possibly the &quot;most recently published product available&quot;, the product was produced for a specific valid period - namely, from 1800Z onward. I would have to reference as different product that was &quot;valid&quot; during my scheduled flight window. &lt;/p&gt;&#xA;" OwnerUserId="7729" LastActivityDate="2018-11-26T17:30:34.670" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15641" PostTypeId="1" AcceptedAnswerId="15648" CreationDate="2018-11-26T21:06:30.660" Score="3" ViewCount="343" Body="&lt;p&gt;The father of a friend of mine passed away recently. He left behind an extensive collection of fossils and minerals. They include a saber tooth tiger skull, mastodon tooth, shark teeth, tons of trilobites, ammonites and others. Some are in good enough shape to be museum quality and some are probably quite valuable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;His father expressed an interest in making sure that the collection was made available hands-on to those who wanted to view or study them rather than be behind glass. I know that some museums provide hands-on access to some items in their collection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My friend has been in contact with some museums but could use some help in identifying schools or other programs where they would be used as his father wanted. We are in Indiana in the US. Any suggestions?&lt;/p&gt;&#xA;" OwnerUserId="14387" LastEditorUserId="14387" LastEditDate="2018-11-27T00:09:34.450" LastActivityDate="2018-11-27T14:20:15.110" Title="Donation Options for Fossil and Mineral Collection" Tags="|fossils|paleontology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15643" PostTypeId="1" CreationDate="2018-11-26T22:01:40.330" Score="4" ViewCount="60" Body="&lt;p&gt;I've been doing some math on the radius of the core (inner core in particular), and I keep getting what look like nonsense results. The composition is supposedly nearly all iron, close enough to it anyway... and I've been using (avg) densities as high as 13,000kg/m&lt;sup&gt;3&lt;/sup&gt;. However, even with density this high I can't get a lower radius than about 2500km. This is using a 0.16 mass for the inner core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Google returns a radius of 1220km for the inner core. It also returns a diameter of 1220km for the inner core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I went so far as to reimplement this an an Excel spreadsheet to double check my code, and I get consistent results.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a good source for the (rough is fine) densities, mass, and radii of the geological layers? I don't trust Google and Wikipedia at this point, and even if I find the answer somewhere else I won't know for sure if they're even close to correct.&lt;/p&gt;&#xA;" OwnerUserId="14388" LastEditorUserId="14388" LastEditDate="2018-11-26T22:26:37.337" LastActivityDate="2018-11-27T00:55:12.340" Title="Do there exist reasonable numbers on the density/radius/mass of the various geological layers of the Earth?" Tags="|geology|core|crust|mantle|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15644" PostTypeId="2" ParentId="15643" CreationDate="2018-11-27T00:47:41.520" Score="4" Body="&lt;p&gt;One model that will help you is the admittedly dated (1981) Preliminary Reference Earth Model. It provides density models for the inner and outer core as functions of distance from the center of the Earth:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\rho =&#xA;\begin{cases}&#xA;13.0885 - 8.8381 x^2 &amp;amp; \quad \phantom{000}0\phantom{.0} \le r \le 1221.5 \\&#xA;12.5815 - 1.2638 x - 3.6426 x^2 - 5.5281 x^3 &amp;amp; \quad 1221.5 \le r \le 3480.0&#xA;\end{cases}&#xA;$$&lt;/span&gt;&#xA;where&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; is the density in grams per cubic centimeter,&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; is distance from the center of the Earth to the point of interest in kilometers, and&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; is the normalized radius: &lt;span class=&quot;math-container&quot;&gt;$x\equiv\frac r {6371}$&lt;/span&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Note that this results in a slight density discontinuity at the boundary between the inner and outer core (1221.5 km). That's intentional. There have been later upgrades to the PREM, but the PREM is where it all starts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reference:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.gps.caltech.edu/classes/ge102/papers/PREM_1981.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dziewonski, Adam M., and Don L. Anderson. &quot;Preliminary reference Earth model.&quot; Physics of the earth and planetary interiors 25.4 (1981): 297-356.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2018-11-27T00:55:12.340" LastActivityDate="2018-11-27T00:55:12.340" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15646" PostTypeId="2" ParentId="15618" CreationDate="2018-11-27T10:25:32.080" Score="2" Body="&lt;p&gt;OK. Let's assume, for the sake of argument, that oceanic and continental crust does have the same density (it doesn't, but that doesn't matter).&#xA;Let's further assume that everything under the earth's crust has constant density (it doesn't, but that also doesn't matter)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To a first approximation, the oceans will form a surface of constant distance from the centre of mass of the earth. Under the assumptions above, if the continents were evenly distributed then the centre of mass would be in the middle of the planet, and we would have a global ocean (minus those continents) of constant depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If all the continents were on one side, then there would be a &lt;em&gt;miniscule&lt;/em&gt; change to the centre of mass of the earth, which would cause the sea level to be slightly higher on the side with the continents than the side without. I'm not going to try to calculate the magnitude of that offset, but bear in mind that the earth is a solid ball of diameter ~12,600km, while the crust is a little 35km layer on top[1]. And the crust is less dense than what's underneath. The continents will make &lt;em&gt;very&lt;/em&gt; little difference to the position of the centre of mass.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's a first approximation. There will also be some direct gravitational attraction between water and continent. This has been calculated (as, interestingly, has that between water and ice sheets), and it does have a measurable effect, increasing sea level close to the land by a small amount. I don't remember whether that amount is of the order of centimetres or metres (can anybody fill me in?), but either way it is not remotely close to being enough to submerge the continents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1] Credit to JeopardyTempest for phrasing this nicely in comments.&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2018-11-28T05:46:10.713" LastActivityDate="2018-11-28T05:46:10.713" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15647" PostTypeId="2" ParentId="7526" CreationDate="2018-11-27T13:57:19.583" Score="4" Body="&lt;p&gt;In addition to what has been (correctly) written in the other answers, I would like to add a couple of figures that could help to understand the dynamics involved:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first figure is borrowed from this interesting &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0959378017300134&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt; &#xA;&lt;a href=&quot;https://i.stack.imgur.com/Vhs93.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Vhs93.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;https://doi.org/10.1016/j.gloenvcha.2017.01.002&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ellison et al. 2017&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, as you correctly guessed, bare lands are &quot;hotter&quot; than forested areas. But when you say &quot;&lt;em&gt;barren land faced greater heating and wind than vegetated area&lt;/em&gt;&quot;, I think you are a little mixing correlation and causality: if the surface is exposed to the same amount of radiations, then the difference in temperature is given by the land cover. The amount of the difference is given by a large number of factors, among which: radiations absorption (including color), topography, composition of the material (rocks, water, soil...), composition of the air surrounding the surface (don't forget that water vapor has a greenhouse effect), area exposed to the radiations, and so on. &#xA;By the combination of all these variables, the presence of trees results, given the same exposure to solar radiations, in a lower temperature. It is curious to notice that in the figure, the fresher area is the pond... This is due to the thermal inertia of water bodies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maintaining the discussion on the forested areas, trees act as a &quot;water pump&quot;: they take soil moisture from the soil and circulating it into their branches and leaves (see next figure). This means that they increase the amount of water available in the surface. Moreover, leaves act as a &quot;surface multiplier&quot;, in the sense that they offer multiple small surfaces that captures the radiation. In addition, the presence of water transfer some of the heat in form of vapor. Basically, leaves do what a human body would do and control their thermal  regulation, also by transpiring large amount of water (&lt;a href=&quot;https://www.nature.com/articles/nplants2016129&quot; rel=&quot;nofollow noreferrer&quot;&gt;see this paper&lt;/a&gt;). &#xA;The cooling effect of the different land cover also influences the winds by altering the convective heat transfer (so, wind is cause and consequence of the &quot;freshness&quot; at the same time).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xxeyV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xxeyV.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This figure is taken from &lt;a href=&quot;https://www.hydrol-earth-syst-sci.net/21/4629/2017/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pereira et al. 2017&lt;/a&gt; and its captions states &quot;&lt;em&gt;Schematic of the enthalpy fluxes (all arrows) and water fluxes (all but solid black arrows) that are solved in ED2. The schematic is based on Walko et al. (2000) and Medvigy et al. (2009). (Figure courtesy of &lt;a href=&quot;https://dash.harvard.edu/handle/1/11744438&quot; rel=&quot;nofollow noreferrer&quot;&gt;Marcos Longo&lt;/a&gt;).&lt;/em&gt;&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In summary, (oversimplifying) the presence of trees increases the amount of water and the surface exposed to the radiations and this, jointly with many other physical and chemical processes, results in a larger moisture in the air and a larger dispersion of the heat (meaning that locally the forested system is fresher than the one without trees). Answering your question in the title: the presence of trees increases the moisture dispersion in the air.&#xA;To give a better sense of the effect of the presence of vegetation on the water balance, see the picture below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/O9TnX.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/O9TnX.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;https://www.nature.com/articles/nclimate1556#f4&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wohl et al 2012&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="8087" LastEditorUserId="8087" LastEditDate="2018-11-28T11:30:49.540" LastActivityDate="2018-11-28T11:30:49.540" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15648" PostTypeId="2" ParentId="15641" CreationDate="2018-11-27T14:14:00.480" Score="2" Body="&lt;p&gt;I work for an university collection and wo often deal with donations. If you contact a museum or university collection, be prepared for the following questions:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;How many fossils are approximately included in the collection?&lt;/li&gt;&#xA;&lt;li&gt;How were they acquired? Were they bought on fossil fairs? Were they self collected?&lt;/li&gt;&#xA;&lt;li&gt;What's the weight of the collection? Sounds weird, but this is important for storage calculation.&lt;/li&gt;&#xA;&lt;li&gt;Is there a list including all specimen?&lt;/li&gt;&#xA;&lt;li&gt;Are all objects properly identified and labeled? This includes the following information: Find locality, Genus, if possible species, geological time including finer stratigraphy. Examples: &lt;em&gt;Diplodocus carnegie&lt;/em&gt;, Upper Jurassic, Morrison Formation, Wyoming or &lt;em&gt;Kallokibotion bajazidi&lt;/em&gt;, Upper Cretaceous, Maastrichtian, Sanpetru, Romania. The more information, the better!&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Why are these questions so important? If you want the objects to be &quot;hands-on&quot; for example for students studying these objects, they have to be properly identified. No student or researcher can work with &quot;trilobite of unknown age and source&quot;. All collections provide hands-on research for those who request it. We do the same. I have a lot of guests coming to our collection wanting to see Triassic ichtyhosaurs, golden ammonites from Opalinus Clay or anything else. In this cases, I prepare all fossils for hands-on access. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In your case, I would recommend the Paleontological Collection of the Indiana University. The collection is quite famous, often visited, and has a very good recommendation all over the world. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.indiana.edu/~palcoll/&quot; rel=&quot;nofollow noreferrer&quot;&gt;See here for their webpage&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13398" LastEditorUserId="13398" LastEditDate="2018-11-27T14:20:15.110" LastActivityDate="2018-11-27T14:20:15.110" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15649" PostTypeId="2" ParentId="10128" CreationDate="2018-11-27T15:48:56.740" Score="3" Body="&lt;p&gt;Check out www.arm.gov an ongoing set of Atmospheric Radiation Measurement experiments at many locations around the globe that measures many aspects of the atmosphere including atmospheric back radiation using infra-red spectroscopy.  This work started in the mid 90's.  Some of the cleanest data comes from the &lt;a href=&quot;https://www.arm.gov/tour/north-slope.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.arm.gov/tour/north-slope.html&lt;/a&gt; North Slope of Alaska ARM research station.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are some articles on the research.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/nature14240&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/nature14240&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://newscenter.lbl.gov/2015/02/25/co2-greenhouse-effect-increase/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://newscenter.lbl.gov/2015/02/25/co2-greenhouse-effect-increase/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14393" LastActivityDate="2018-11-27T15:48:56.740" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15653" PostTypeId="1" CreationDate="2018-11-27T23:04:03.523" Score="7" ViewCount="6573" Body="&lt;p&gt;At the present time, about 70% of the earth's surface is liquid water (perhaps that includes floating ice around Antarctica, and the Arctic Ice cap).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What percentage of the Earth's surface would be water if ALL the ice had melted?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've seen illustrations of the new shoreline, and I've seen estimates of the rise in sea level, but no answer to my question.&lt;/p&gt;&#xA;" OwnerUserId="14397" LastEditorUserId="11908" LastEditDate="2019-03-17T19:43:37.727" LastActivityDate="2022-10-09T01:03:12.757" Title="If ALL the ice melted, what percentage of the Earth's surface would be water?" Tags="|oceanography|geography|glaciology|sea-level|topography|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="15654" PostTypeId="1" AcceptedAnswerId="15660" CreationDate="2018-11-28T06:12:31.603" Score="6" ViewCount="141" Body="&lt;p&gt;I looked up nearly everywhere on the internet, but couldn't find any evidence that snow wouldn't melt because of ice. When I look it up, it instead tells me how salt can melt snow. &lt;strong&gt;I'm NOT looking up on salt!&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the best weather-related StackExchange I could find, so I posted this question on this website. Also, I live in a hot desert climate, so it'd be hard to test it out in real life.&lt;/p&gt;&#xA;" OwnerUserId="14398" LastEditorUserId="11908" LastEditDate="2019-03-13T05:10:17.707" LastActivityDate="2019-03-13T05:10:17.707" Title="Does snow melt on ice?" Tags="|meteorology|glaciology|extreme-weather|cryosphere|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15655" PostTypeId="2" ParentId="15654" CreationDate="2018-11-28T08:05:59.693" Score="-1" Body="&lt;p&gt;Yes.. If snow is lying on ice and is warmed by sunlight then it will melt. &lt;/p&gt;&#xA;" OwnerUserId="14400" LastActivityDate="2018-11-28T08:05:59.693" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15656" PostTypeId="1" AcceptedAnswerId="15658" CreationDate="2018-11-28T09:51:50.640" Score="9" ViewCount="518" Body="&lt;p&gt;There are a lot of reports on the consequences of climate change for the relative short term. From what I understand, in the next 100 years or so, we will face:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;global floods of coastal areas, causing large-scale migrations;&lt;/li&gt;&#xA;&lt;li&gt;desertification of desert-adjacent regions, leading to more migrations and less arable land;&lt;/li&gt;&#xA;&lt;li&gt;more and longer periods of drought and heatwave, leading to failed crops and hunger epidemics;&lt;/li&gt;&#xA;&lt;li&gt;changes in local climate, leading to changes in biodiversity and possibly introduction of pathogens in areas that before were inhospitable to the carrier;&lt;/li&gt;&#xA;&lt;li&gt;...&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I might be totally mistaken here, but while these things are definitely cause for serious concern and good reasons to take action, they don't seem like they could cause the end of life on Earth as some people claim, or even the extinction of Humanity. I'm fairly sure that even though loads of people might die due to the consequences of climate change, humanity as a species would probably survive. I might be wrong though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could climate change lead to the extinction of humanity?&lt;/p&gt;&#xA;" OwnerUserId="1013" LastActivityDate="2018-11-30T20:01:12.277" Title="Could the current climate change events cause long-term problems in the viability of Earth to sustain life?" Tags="|climate-change|mass-extinction|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15657" PostTypeId="2" ParentId="15656" CreationDate="2018-11-28T10:21:43.607" Score="2" Body="&lt;p&gt;Depends on the further actions humanity takes. If we keep on pumping green house gases into the atmosphere, survival will become significantly harder. Sure, we most likely wont be able to create a Venus-like atmosphere, but as of today we simply do not know, what tipping points in the climate system we might go beyond.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Actually I am more concerned by the steps humanity might take in the wake of climate change. On the one hand, all out war is a possibility, diminishing our capabilities to cope with the consequences of climate change. On the other hand, we might be so &quot;brilliant&quot; as to dabble in geo-engineering - and really fuck up the climate system beyond repair. Imagine someone like Trump fighting climate change instead of imigration - the consequences could be catastrophic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Specific forecasts are out of the question - but basically, I think there is a very slim chance we as a species could go extinct - alongside most of the other animals. Our current consumption of ressources definitely wont be possible anymore.&lt;/p&gt;&#xA;" OwnerUserId="14194" LastActivityDate="2018-11-28T10:21:43.607" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15658" PostTypeId="2" ParentId="15656" CreationDate="2018-11-28T10:22:56.380" Score="4" Body="&lt;p&gt;There is one scenario in which climate change could render the Earth inhospitable to life in general, which would be a &lt;a href=&quot;https://en.wikipedia.org/wiki/Runaway_greenhouse_effect&quot; rel=&quot;nofollow noreferrer&quot;&gt;runaway greenhouse effect&lt;/a&gt;.  In a runaway greenhouse effect, the Earth would get so hot that the oceans start to evaporate, adding more water vapour (powerful greenhouse gas) to the atmosphere, which will make it hotter yet, until Earth ends up like Venus.&#xA;However, the current scientific consensus is that a runaway greenhouse effect as a consequence of anthropogenic global warming is not possible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Life in general will almost certainly go on, and most consider it unlikely that the survival of humanity itself is at risk as a direct consequence of climate change.  Many other species, however, will likely disappear, as has been widely documented in the scientific literature.  As an example, complicated ecosystems depend on coral reefs, and as things stand, there may not be any coral reefs left by the end or even the middle of the century.  This will be disastrous for significant subpopulations of humanity (I've heard in a talk last week than 400 million people depend on fish supported by ecosystems around coral reefs), but it will not by itself cause the extinction of mankind.&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2018-11-28T10:22:56.380" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15660" PostTypeId="2" ParentId="15654" CreationDate="2018-11-28T16:43:27.757" Score="6" Body="&lt;p&gt;Yes, a layer of snow on top of ice can melt in some circumstances. For example, one active area of climate research involves analyzing the optical properties of sea ice as they relate to incoming solar radiation. In some studies (e.g., &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2003JC002042&quot; rel=&quot;noreferrer&quot;&gt;Ehn et al. 2004&lt;/a&gt;) this involves snow layered on top of ice, with the snow explicitly melting (and later refreezing) over the diurnal heating cycle in some cases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a more specific recent illustration, this phenomenon was also reported for the Canadian Lowell Glacier in July 2018 by &lt;a href=&quot;https://www.earthobservatory.nasa.gov/images/92699/ldquosnow-swamprdquo-on-lowell-glacier&quot; rel=&quot;noreferrer&quot;&gt;NASA&lt;/a&gt;. Abnormally warm air temperatures (up to 29°C/84°F, according to nearby surface observations) over several days resulted in the melting of surface snow while the deeper ice below remained intact - a process referred to as &lt;a href=&quot;https://nsidc.org/cryosphere/glossary/term/ablation&quot; rel=&quot;noreferrer&quot;&gt;ablation&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="14078" LastActivityDate="2018-11-28T16:43:27.757" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15661" PostTypeId="2" ParentId="15618" CreationDate="2018-11-28T18:37:54.430" Score="0" Body="&lt;p&gt;OK, I'm sufficiently fed up with this to attempt a mathematical answer. It'll be very approximate, but it'll demonstrate an upper limit to how much the sea is skewed to one side of the planet (it's actually more than I expected). I fully expect to get something wrong here; if it's something that matters, please tell me about it!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's imagine a cartoon planet that consists of two parts:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A sphere of radius 6370 km&lt;/li&gt;&#xA;&lt;li&gt;A half-shell of &quot;continentals&quot; with a thickness of 4 km (representing the distance from seafloor to continent)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;For simplicity we'll assume that all of these have equal density, and in arbitrary units we'll define that density to be 1. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We want to find where the centre of mass of this &quot;planet&quot; is. Let's define our coordinate system to work in one dimension, along a line running from the middle of one half-shell to the middle of the other, where x=0 is at the centre of the sphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a diagram (not to scale):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pdbJ5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pdbJ5.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$r_1=6370$&lt;/span&gt; km; &lt;span class=&quot;math-container&quot;&gt;$r_2=6374$&lt;/span&gt; km&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mass of the sphere, in arbitrary mass units, is &lt;span class=&quot;math-container&quot;&gt;$\frac{4}{3} \pi r_1^3 = 1.1\times 10^{12}$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mass of the continental half-shell is &lt;span class=&quot;math-container&quot;&gt;$\frac{1}{2}\cdot\frac{4}{3} \pi (r_2^3 - r_1^3)=10^9$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The centre of mass (CoM) of the sphere is at &lt;span class=&quot;math-container&quot;&gt;$x=0$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I had to look up online how to find the centre of mass of a hemispherical shell, but it turns out that it lies at &lt;span class=&quot;math-container&quot;&gt;$x=\frac{3}{8}\frac{r_2^4 - r_1^4}{r_2^3 - r_1^3} = 3186$&lt;/span&gt; km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To find the location of the centre of mass of the combined object, we use&#xA;&lt;span class=&quot;math-container&quot;&gt;$x_c = \frac{m_1d_1 + m_2d_2}{m_1 + m_2}$&lt;/span&gt; where each &lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt; is a mass and each &lt;span class=&quot;math-container&quot;&gt;$d$&lt;/span&gt; is the position of the centre of mass of that object. So,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$x_c = \frac{1.1 \times 10^{12} \times 0 + 10^9 \times 3186}{1.1\times 10^{12} + 10^9} = 2.9 $&lt;/span&gt; km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the centre of mass of our cartoon planet is 2.9 km closer to the &quot;continent&quot; side than the &quot;ocean&quot; side. That means that the ocean will, rather approximately, try to form a shell centred on that point, thus being 2.9 km deeper in the centre of the continent than in the centre of the ocean. Errr...&#xA;Except that the sea wouldn't actually do this because it would be blocked by the giant continent that's in its way. To figure out what would actually happen would require doing the maths in 3D, and possibly involving tractive forces and the like, and that's well beyond my capability this afternoon ;-)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I emphasise once again that this is an extremely generous scenario - half of the planet is continent, which is more than on Earth, and everything has the same density, rather than the inside of the planet being denser than the crust (which would make the effect much weaker). Plus, once we're dealing with values of a few km, in the real world there are probably other variations (e.g. equatorial bulge, non-ellipsoisal geoid due to density variations, etc) that have much bigger effects.&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2018-11-30T06:54:20.347" LastActivityDate="2018-11-30T06:54:20.347" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="15666" PostTypeId="1" CreationDate="2018-11-29T13:00:50.790" Score="6" ViewCount="65" Body="&lt;p&gt;&lt;a href=&quot;https://mars.nasa.gov/mer/spotlight/hematite01.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hematite on Mars&lt;/a&gt; is generally thought to have formed either in pools of water or from volcanic activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A comment to the answer to the question: &lt;em&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/6910/how-do-hematite-and-magnetite-form&quot;&gt;How do hematite and magnetite form?&lt;/a&gt;&lt;/em&gt; states that sodium hypochlorite can act as an oxidizer to help form hematite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know hypochlorite is different from perchlorate, but &lt;a href=&quot;https://www.nasa.gov/ames/ocs/workshops/pom&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mars contains so much perchlorate&lt;/a&gt; that its soils are considered to be toxic to life.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could the perchlorates on Mars have been influential in the formation of hematite?&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorDisplayName="user20559" LastEditDate="2021-05-10T10:21:58.633" LastActivityDate="2021-05-10T10:21:58.633" Title="Formation of Hematite on Mars via Perchlorates as an Oxidizer" Tags="|geology|geochemistry|mineralogy|mars|iron|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15667" PostTypeId="2" ParentId="15594" CreationDate="2018-11-29T14:10:31.030" Score="1" Body="&lt;p&gt;One suggestion on generating the monthly flows is to use a seasonal ARMA model directly (e.g. see &lt;a href=&quot;https://faculty.fuqua.duke.edu/~rnau/Decision411_2007/seasarim.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;course notes&lt;/a&gt;), since you are looking at ARMA model for stochastic generation anyway. That would allow the explicit estimation of seasonal parameters for synthetic generation, and let you skip the step of going annual --&gt; monthly, instead go monthly and calculate annual flows from the monthly series. You may have other reasons for wanting to start with annual flows to verify those first, but that is one suggestion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of physical concepts at a monthly flow resolution, this is harder to comment on without knowing what physical processes are impacting your streamflows, e.g. snowmelt, river ice and freezing, spring freshet, depression storage, etc. One suggestion may be to check monthly volumes and peaks as well as timing of peaks (such as spring freshet), and ensure that any synthetic time series match these statistics within some acceptable boundary, throwing out any simulations that are deemed unacceptable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a pretty broad (research level) question but hopefully that gives some ideas.&lt;/p&gt;&#xA;" OwnerUserId="8440" LastActivityDate="2018-11-29T14:10:31.030" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15668" PostTypeId="1" CreationDate="2018-11-29T15:21:18.767" Score="1" ViewCount="79" Body="&lt;p&gt;Why does CO2 cause heating in troposphere but cooling mesosphere?&#xA;Can anyone explain this?&lt;/p&gt;&#xA;" OwnerUserId="14409" LastActivityDate="2018-11-29T15:21:18.767" Title="Why does CO2 cause heating in troposphere but cooling mesosphere?" Tags="|troposphere|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15669" PostTypeId="1" CreationDate="2018-11-29T17:01:17.670" Score="8" ViewCount="1765" Body="&lt;p&gt;If we were to make some technical jump to renewable fuel and renewable energy, would making plastics from oil release green house gasses, how much, and would plastic function as a carbon sink?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sorry if this is a basic question I don’t know much about earth science.&lt;/p&gt;&#xA;" OwnerUserId="14410" LastActivityDate="2019-09-17T19:59:47.977" Title="Are plastics a carbon sink and how much carbon is released to the atmosphere making them?" Tags="|climate-change|gas|greenhouse-gases|plastic|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15670" PostTypeId="1" AcceptedAnswerId="15673" CreationDate="2018-11-29T17:40:10.590" Score="2" ViewCount="2307" Body="&lt;p&gt;From the weather forecasting perspective: what is the main reason for showing just map of 500 hPa geopotential? Are there any practical or theoretical reasons? Why do not show 600 hPa geopotential or 400 hPa instead?&#xA;I understand that forecast model usually operates at pressure levels, so this is the reason why choose pressure level instead of quantity at some altitude. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let us take e.g.:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ecmwf.int/en/forecasts/charts/catalogue/medium-z500-t850-public?facets=Range,Medium%20(15%20days)&amp;amp;time=2018112900,0,2018112900&amp;amp;projection=classical_europe&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ecmwf.int/en/forecasts/charts/catalogue/medium-z500-t850-public?facets=Range,Medium%20(15%20days)&amp;amp;time=2018112900,0,2018112900&amp;amp;projection=classical_europe&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14411" LastEditorUserId="14411" LastEditDate="2018-11-30T10:42:35.960" LastActivityDate="2018-11-30T11:45:41.963" Title="What is are the benefits of map 500 hPa geopotential for weather forecasting?" Tags="|meteorology|weather-forecasting|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15671" PostTypeId="2" ParentId="15670" CreationDate="2018-11-29T18:53:11.263" Score="2" Body="&lt;p&gt;The link you provided states at the bottom of the page that 500hPa (500mb) is used because the weather systems as the Earth's surface move with the winds at this height (approximatly 5.5km above the surface). It makes sense to show just the 500hPa on these maps as this is the most applicable height for forecasting weather system movement. More pressures/heights would make a single map confusing and not really be worthwhile. I hope this helps. Feedback would be welcome. &lt;/p&gt;&#xA;" OwnerUserId="14291" LastActivityDate="2018-11-29T18:53:11.263" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15672" PostTypeId="2" ParentId="15669" CreationDate="2018-11-29T18:58:54.203" Score="2" Body="&lt;p&gt;Plastic is a much less efficient carbon sink than the original crude oil if it had been left in the ground or any natural method for storing carbon such as peat bogs. It is still technically a carbon sink but is starting to be broken down naturally so is not a renewable or sustainable one. Pollution and green house gasses are a major part of plastic production so environmentally it does not make sense to produce plastics a carbon sink unless you were converting biodegradable plastic into  non biogradeable plastic without releasing any harmful gasses in the process. Hope this helps.&lt;/p&gt;&#xA;" OwnerUserId="14291" LastActivityDate="2018-11-29T18:58:54.203" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15673" PostTypeId="2" ParentId="15670" CreationDate="2018-11-30T01:50:15.660" Score="4" Body="&lt;p&gt;The 500 hPa geopotential is usually called the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Level_of_nondivergence&quot; rel=&quot;nofollow noreferrer&quot;&gt;Level of non divergence&lt;/a&gt;. It is understood that beneath that level there is a level of convergence and above that level there is a level of divergence so that this surface(500 hPa) is the surface to look for vertical motions. To  a first approximation one can assume the time derivative of density of a particular surface to be a constant and then set the continuity equation to be zero. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\nabla. u = 0  $$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can then expand on the terms on the LHS and separate the horizontal components from the vertical components. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This turns out to be(in isobaric coordinates) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ \nabla_H. u_H = -\frac{ \partial \omega}{\partial p}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One can then conclude from this equation the following&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) If the LHS is less than zero then there is an increase in vertical velocity with decreasing pressure&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) If the LHS is greater than zero then there is a decrease in vertical velocity with decreasing pressure&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the atmosphere is bounded at two levels (the surface and tropopause) the vertical velocity is close to zero at these two levels. However in between these two boundaries the vertical velocity starts to increase and achieves it's maximum value before again tapering off at the tropopause. The level of maximum vertical motion is usually the 500 hPa and this is also called the level of non divergence.  &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2018-11-30T11:45:41.963" LastActivityDate="2018-11-30T11:45:41.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15676" PostTypeId="2" ParentId="15656" CreationDate="2018-11-30T20:01:12.277" Score="2" Body="&lt;p&gt;100 years is not very long-term at all.  The added CO2 will not miraculously disappear after a century, but will go on warming the planet.   (And that's just assuming that humans stop burning fossil fuels now.) There are all sorts of feedback effects that will come into play at some point, if they haven't already.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For one example, a lot of CO2 winds up dissolved in the oceans, and the solubility is inversely proportional to water temperature.  As the ocean warms due to human-generated CO2 in the atmosphere, it becomes less able to serve as a CO2 sink, and eventually would release some of its existing CO2, causing further warming.  The ocean mixing time (between surface and deep ocean) is on the order of 1000 years, so whatever is set in motion today keeps on happening.  The warming ocean might also trigger the release of methane clathrates: &lt;a href=&quot;https://en.wikipedia.org/wiki/Clathrate_gun_hypothesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Clathrate_gun_hypothesis&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, we don't really have to theorize that much about the long-term effects, since we have a reasonably close parallel from Earth's geologic past: the Permian-Triassic extinction event: &lt;a href=&quot;https://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extinction_event&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extinction_event&lt;/a&gt;  One leading theory for the cause of this is that major vocanic eruptions (the Siberian Traps)  took place in an area of coal beds, setting them on fire.   This of course added lots of CO2 to the air, just as human use of fossil fuels has.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the hypothesis is that the current warming (and future warming that is already &quot;baked in&quot; by the already-released CO2) will trigger unstoppable feedback effects.  Not quite a runaway &quot;Venus Effect&quot; (that's probably impossible on Earth), but one that causes mass extinctions.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some people think that humans would survive those mass extinctions.  I doubt that*, myself.  Too many people live lives divorced from the natural world (thinking for instance that food comes from supermarkets &amp;amp; fast-food joints), and so fail to appreciate just how strongly human survival depends on the existence of the global ecosystem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*Of course this is opinion.  The only way to test it (other than computer models) is to perform the experiment, which is analogous to checking whether a gun is loaded by pointing it at your kid and pulling the trigger :-)&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2018-11-30T20:01:12.277" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15679" PostTypeId="2" ParentId="15669" CreationDate="2018-12-01T02:47:28.403" Score="5" Body="&lt;p&gt;The idea of a carbon sink is a bit misunderstood here. The idea of a carbon sink is a reduction of carbon that comes from the atmosphere. It must “fix” carbon that is already in the air. Trees are a carbon sink, for the most part, because their mass is made of of carbon obtained from&#xA;The atmosphere. Unless the plastic formation process you are thinking of is vastly different that any industrialized ones, they are taking carbon from oil essentially. Since the carbon from the oil&#xA;Has not yet been released into the atmosphere, it would not qualify as a sink.&lt;/p&gt;&#xA;" OwnerUserId="14419" LastEditorUserId="39" LastEditDate="2019-09-17T19:59:47.977" LastActivityDate="2019-09-17T19:59:47.977" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15680" PostTypeId="2" ParentId="15572" CreationDate="2018-12-01T03:25:57.790" Score="1" Body="&lt;p&gt;Here is some supplemental material for the good answer above. It won’t let me comment, &lt;a href=&quot;http://www.fao.org/docrep/x5871e/x5871e04.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.fao.org/docrep/x5871e/x5871e04.htm&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14419" LastActivityDate="2018-12-01T03:25:57.790" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15684" PostTypeId="1" CreationDate="2018-12-01T16:20:55.373" Score="2" ViewCount="258" Body="&lt;p&gt;In the docudrama Super Comet After the Impact, the impact is shown to have made the air within a few miles of it unbreathable, and humans need gas masks to breath in this area.&#xA;How realistic is this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was told to come here after originally posting on the space stack.&lt;/p&gt;&#xA;" OwnerUserId="14422" LastEditorUserId="725" LastEditDate="2018-12-02T00:13:26.290" LastActivityDate="2020-10-25T06:00:55.093" Title="Could dust blown up by a comet impact render the air unbreathable?" Tags="|atmosphere|climate|human-influence|impacts|" AnswerCount="4" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="15688" PostTypeId="1" CreationDate="2018-12-02T05:23:28.910" Score="0" ViewCount="104" Body="&lt;p&gt;Looking at the Earth system as a whole and considering ecological economics, &lt;a href=&quot;https://en.wikipedia.org/wiki/Primary_production&quot; rel=&quot;nofollow noreferrer&quot;&gt;net primary productivity&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Emergy&quot; rel=&quot;nofollow noreferrer&quot;&gt;emergy&lt;/a&gt; are two concepts that strike me as fundamental and likely related. I'm not sure what the relationship is though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd define emergy as embodied energy, or how much total gross joules are embodied in a given process or material (or organism).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd define net primary production as the total mass of organic compounds synthesized from &quot;inorganic carbon&quot; (primarily atmospheric carbon dioxide). While this metric is a mass, it also sheds light on how relatively efficiently solar energy is used to generate life (or at least the ingredients of life, &quot;organic&quot; carbon compounds). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At first these two metrics seem quite different: one is a measure of energy, one is a mass. However, both metrics clarify the relationship between our relatively open-system energy resource and our closed-system nutrient cycles. For example, I in comparing different agroecosystems growing an apple, emergy can help show the energetic efficiency of each system and net primary production can help show the life-generating efficiency of each system. My word choices there seem a little ambiguous, for example, what's the difference between &quot;energetic efficiency&quot; and &quot;life-generating efficiency&quot;? That's what spurs the main question, which is: &lt;strong&gt;what, if any, is the relationship between net primary productivity and emergy?&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clarification about the qualitative relationship between the two metrics would be helpful, I understand it may be overly complex to quantify it though the two terms are very much quantitative. Researching this I've found plenty of resources about each metric but none yet comparing the two, so any resources simply comparing the two would be an answer/step in the right direction.&lt;/p&gt;&#xA;" OwnerUserId="4789" LastActivityDate="2018-12-02T05:23:28.910" Title="What is the relationship between net primary productivity and emergy?" Tags="|solar-terrestrial-physics|energy-balance|nutrient-cycles|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15689" PostTypeId="2" ParentId="15684" CreationDate="2018-12-02T20:22:54.650" Score="1" Body="&lt;p&gt;That doesnt seem realistic since eventually all the dust from all the volcanic activity, as well as that caused by our doing, eventually makes its way back down to earth. Most dust particles end up being soaked up by earths cloud layer coming down in rain. I have to agree with Gimelist but volcanism can and has produced conditions you mentioned by expelling caustic and poisonous gases and for what I understand nuclear detonations and the radioactive dust they send into the air is far worse in the long run.&lt;/p&gt;&#xA;" OwnerUserId="12495" LastActivityDate="2018-12-02T20:22:54.650" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15693" PostTypeId="1" CreationDate="2018-12-03T14:11:09.343" Score="3" ViewCount="628" Body="&lt;p&gt;How much speed of surface currents decrease in ocean depth? Approximately? I am wondering if there is any significant gradient within the top 30m ocean layer? Can this be theoretically calculated?&lt;/p&gt;&#xA;" OwnerUserId="14434" LastActivityDate="2018-12-04T11:34:53.570" Title="Velocity gradient of surface ocean current in dephts" Tags="|ocean-currents|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15697" PostTypeId="1" CreationDate="2018-12-03T21:57:55.143" Score="9" ViewCount="320" Body="&lt;p&gt;According to &lt;a href=&quot;http://www.caverbob.com/wdeep.htm&quot; rel=&quot;noreferrer&quot;&gt;http://www.caverbob.com/wdeep.htm&lt;/a&gt; and &lt;a href=&quot;http://www.caverbob.com/usadeep.htm&quot; rel=&quot;noreferrer&quot;&gt;http://www.caverbob.com/usadeep.htm&lt;/a&gt;, the only cave over 1000m deep in the US is a lava cave in Hawaii. In the continental US the deepest is 505m.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand in Europe there are two caves over 2000m deep.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The largest cave systems are in the US (&lt;a href=&quot;https://www.nps.gov/maca/index.htm&quot; rel=&quot;noreferrer&quot;&gt;Mammoth Cave&lt;/a&gt; in Kentucky. Why aren't they deeper?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems that the limestone layers are thinner and have been tilted less than in Europe. If this is the case, why?&lt;/p&gt;&#xA;" OwnerUserId="14439" LastEditorUserId="6298" LastEditDate="2018-12-04T02:31:16.037" LastActivityDate="2019-04-02T00:17:11.467" Title="Why are there no deep caves in the continental US?" Tags="|geology|cavern|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="15698" PostTypeId="1" CreationDate="2018-12-03T23:11:51.357" Score="5" ViewCount="63" Body="&lt;p&gt;Melted polar ice water makes the oceans deeper on average.  The extra water on top of the oceanic plates makes them sink relative to the continental plates. This relative vertical displacement will facilitate the subduction of any oceanic plates that are currently stuck (like the one off the coast of Oregon, which is about 500 years over due for a massive jerk that will set off the long anticipated &quot;Big One&quot;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is like car bumpers: if the bumper of a lighter, pushed car is higher than the bumper of a heavier, pushing car, the pushed car bumper will eventually ride up onto the bumper of the pushing car when the weight disparity becomes great enough. The greater the disparity, the more pronounced the effect. &lt;/p&gt;&#xA;" OwnerUserId="14440" LastActivityDate="2018-12-05T03:02:45.820" Title="When will the weight of melted polar ice release the (currently stuck) subduction of the oceanic plate West of the Oregon coast?" Tags="|geology|hydrology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15699" PostTypeId="2" ParentId="15693" CreationDate="2018-12-04T11:34:53.570" Score="3" Body="&lt;p&gt;Yes, the speed of currents varies with depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case of shallow, coastal water, the flow is retarted by friction at the seabed, so it is slowest at the seabed and usually has a curve of increasing speed towards the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This curve can theoretically be calculated, but in practice it is very sensitive to things like the material and shape of the seabed, wind and waves near the surface, and so forth, so while estimates can be made from theory, it's usually better to measure it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Approximations are often made using a &quot;power law&quot; such as &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$u_1 = u_2 \left( \frac{z_2}{z_1} \right)^{\frac{1}{\alpha}}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$u_1$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$u_2$&lt;/span&gt; are the speeds at distances &lt;span class=&quot;math-container&quot;&gt;$z_1$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$z_2$&lt;/span&gt; above the seabed respectively, and &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt; is an arbitrary value often between 5 and 7.&#xA;This figure, from &lt;a href=&quot;http://doi.org/10.1016/j.renene.2017.03.096&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lewis et al. 2017&lt;/a&gt; (creative commons licensed), illustrates a number of such theoretical curves with different values of &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oe5VM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oe5VM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In deeper oceans this mechanism will only apply close to the seabed; however, far more complex systems can come into play, with different water bodies moving in (potentially) different directions. Possibly others with more expertise in ocean dynamics can address that case.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2018-12-04T11:34:53.570" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15700" PostTypeId="1" AcceptedAnswerId="15702" CreationDate="2018-12-04T22:31:02.743" Score="2" ViewCount="392" Body="&lt;p&gt;I'm looking to download a small geographic area of the CMIP5 models part of NASA-NEX dataset. Previously I relied on the Planet OS OpenNEX GDDP website which had a great tool for selecting geographic areas, models and time periods, saving in this way a large amount of downloading time and disk space. The problem is that OpenNEX is gone and I haven't been able to find a similar tool.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there another tool/website/script that can be used similarly?&lt;/p&gt;&#xA;" OwnerUserId="12452" LastActivityDate="2018-12-05T09:49:53.203" Title="where to download NASA-NEX daily downscaled datasets?" Tags="|climate-change|climate|climate-models|gis|nasa|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15702" PostTypeId="2" ParentId="15700" CreationDate="2018-12-05T07:36:42.447" Score="2" Body="&lt;p&gt;Google Earth Engine's &lt;a href=&quot;https://developers.google.com/earth-engine/datasets/catalog/NASA_NEX-DCP30_ENSEMBLE_STATS&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA NEX dataset&lt;/a&gt; (or &lt;a href=&quot;https://developers.google.com/earth-engine/datasets/catalog/NASA_NEX-GDDP&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;) might be of interest to you. It is an online repository, where you can do your analysis using the GEE platform without having the need to download to local machine.&lt;/p&gt;&#xA;" OwnerUserId="14450" LastActivityDate="2018-12-05T07:36:42.447" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15703" PostTypeId="2" ParentId="6706" CreationDate="2018-12-05T08:42:27.773" Score="1" Body="&lt;p&gt;Some confusion comes from the mixture of analysis data (such as 2m-air temperature) and reanalysis products (such as downward radiation) in the final reanalysis product. The following text directly from ECMWF may help&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://confluence.ecmwf.int/pages/viewpage.action?pageId=56658233&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://confluence.ecmwf.int/pages/viewpage.action?pageId=56658233&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14452" LastActivityDate="2018-12-05T08:42:27.773" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15704" PostTypeId="2" ParentId="15700" CreationDate="2018-12-05T09:22:35.390" Score="0" Body="&lt;p&gt;Besides the Google Earth application suggested by &lt;code&gt;shahryar&lt;/code&gt; I'm not aware of an online tool that could do the job you are looking for.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I would do is to download the files and operate with a NCO or CDO to select the domain you are after (so that you can get rid of the &quot;big&quot; file immediately after and save disk space).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are working on a windows machine and cannot use NCO or CDO, a way to automatize at least the downloading procedure would be a script in R.&#xA;Something like this:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;library(RCurl)&#xA;opts = curlOptions(proxy='my_proxy', userpwd = &quot;mypassword&quot;, netrc = TRUE) ##you need to get the credentials beforehand&#xA;&#xA;var = c(&quot;pr&quot;,&quot;tasmax&quot;,&quot;tasmin&quot;) # put variables here&#xA;rcp = c(&quot;rcp45&quot;, &quot;rcp85&quot;) #put the Climate scenarios here&#xA;mod= c(&quot;CCSM4&quot;, &quot;GFDL-CM3&quot;, &quot;IPSL-CM5A-MR&quot;, &quot;MIROC5&quot;,  &quot;inmcm4&quot;) #put the GCM models you want here&#xA;year=c(seq(2036,2050,1), seq(2086,2100,1)) ##here you can select the years you are looking for&#xA;&#xA;for (v in var) {&#xA;  for (r in rcp) {&#xA;    url&amp;lt;- paste0( 'ftp://ftp.nccs.nasa.gov/BCSD/', r, '/day/atmos/', v, '/r1i1p1/v1.0/', sep='')&#xA;    for (m in mod) {&#xA;      for (y in year) {&#xA;        nfile&amp;lt;- paste0(v,'_day_BCSD_',r,&quot;_r1i1p1_&quot;,m,'_',y,'.nc', sep='')&#xA;        url1&amp;lt;- paste0(url,nfile, sep='')&#xA;        destfile&amp;lt;-paste0('your_destination_path_NASA_NEX/',r,'/',v,'/',nfile, sep='')&#xA;        bin &amp;lt;- getBinaryURL(url1, .opts = opts)&#xA;        writeBin(bin, destfile)&#xA;        Sys.sleep(1)&#xA;        gc()&#xA;      }&#xA;    }&#xA;  }&#xA;}&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;In the middle of the loop, using &lt;code&gt;ncdf4&lt;/code&gt; (give a look &lt;a href=&quot;https://stackoverflow.com/questions/21280104/how-to-take-a-subset-from-a-netcdf-file-using-latitude-longitude-boundaries-in-r&quot;&gt;here&lt;/a&gt;) you can nest few lines to pick the portion of the data covering your domain, store it, and get rid of the original file you just downloaded.&#xA;This is time consuming though. Surely it would be more efficient to use a combination of &lt;code&gt;wget&lt;/code&gt; (as explained &lt;a href=&quot;https://nex.nasa.gov/nex/resources/366/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here by NASA&lt;/a&gt;) and then &lt;code&gt;NCO&lt;/code&gt; or &lt;code&gt;CDO&lt;/code&gt;.&lt;/p&gt;&#xA;" OwnerUserId="8087" LastEditorUserId="8087" LastEditDate="2018-12-05T09:49:53.203" LastActivityDate="2018-12-05T09:49:53.203" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15705" PostTypeId="1" CreationDate="2018-12-05T10:43:28.470" Score="9" ViewCount="1568" Body="&lt;p&gt;In my old textbooks, &lt;strong&gt;granites&lt;/strong&gt; used to be part of the &lt;strong&gt;metamorphic&lt;/strong&gt; rocks.&lt;br&gt;&#xA;Is this still true or not ? If not fully true, to which extent ?&lt;br&gt;&#xA;Could someone point me towards clear examples or definitions showing they are considered &lt;em&gt;not metamorphic&lt;/em&gt; rocks any more ?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If not metamorphic, please which part of the rock classification do they belong to exactly ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks,   Gilbert.&lt;/p&gt;&#xA;" OwnerUserId="14435" LastActivityDate="2021-09-30T04:55:39.060" Title="Could one say that granites are metamorphic rocks, or not at all?" Tags="|rocks|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15709" PostTypeId="1" AcceptedAnswerId="15739" CreationDate="2018-12-05T23:05:56.183" Score="1" ViewCount="454" Body="&lt;p&gt;When it comes to land or marine acquisition (oil exploration, for instance), I can see from literature that quality control (QC) is performed during the survey to ensure that the seismic traces obtained are not faulty. However, I see contradicting values for the amount of data that is required for QC. In [1], it is mentioned that just around 10 bytes/minute are sufficient. Meanwhile in [2], it is mentioned that the data collected over the entire day is used for QC. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can someone point me to a good source where I can understand this aspect better?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1] - &lt;a href=&quot;http://home.deib.polimi.it/savazzi/articles/06495774mag.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://home.deib.polimi.it/savazzi/articles/06495774mag.pdf&lt;/a&gt; (Page 3, second paragraph under 'Shooting-Blind vs Real Time Telemetry Systems)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[2] - &lt;a href=&quot;http://www.smngc.ru/en/seismic-surveys/quality-control-of-the-seismic-data/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.smngc.ru/en/seismic-surveys/quality-control-of-the-seismic-data/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11056" LastActivityDate="2018-12-10T02:49:31.667" Title="Quality control in Seismic Acquisition - How much data is required?" Tags="|geophysics|seismology|seismic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15711" PostTypeId="1" AcceptedAnswerId="15721" CreationDate="2018-12-06T13:21:39.230" Score="5" ViewCount="1737" Body="&lt;p&gt;Following the commonly-known USGS &lt;a href=&quot;https://en.wikipedia.org/wiki/Water_year&quot; rel=&quot;nofollow noreferrer&quot;&gt;definition&lt;/a&gt; of Water Year (or Hydrological Year) we know that it starts on the 1st October and ends on the next 30th September.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this definition valid only for temperate/mid-latitudes?&#xA;What's the water year e.g. in the Equatorial, Polar and Arid regions?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can I keep using the USGS definition for these areas or shall I just use the calendar year (1st January-31st December)? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks &lt;/p&gt;&#xA;" OwnerUserId="11493" LastEditorUserId="18375" LastEditDate="2019-11-21T12:45:42.373" LastActivityDate="2019-11-21T12:45:42.373" Title="Are the water year/hydrological year different around the world?" Tags="|hydrology|water|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15714" PostTypeId="1" CreationDate="2018-12-06T16:54:24.610" Score="1" ViewCount="54" Body="&lt;p&gt;I made a fire defense space about 100' by 50' behind my two level home on a 20% slope surrounded by old, tall pines. On July 14, 2018, I saw thin white jagged lines moving across the open space that appeared to me to be low flying lightning and made a note of the event on my calendar, where I also record the daily low &amp;amp; high temperatures as well as any rain, snow, or hail. During the two days before and after the event there was no rain and temps were between low to high 60s a.m. and 84 to 94 degrees p.m. I do not recall whether there were any clouds on 7/14.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could what I see have been generated by a natural phenomenon (or could it have something to do nearby PG&amp;amp;E power and phone poles in combination with weather circumstances)?&lt;/p&gt;&#xA;" OwnerUserId="14464" LastEditorUserId="595" LastEditDate="2018-12-07T08:33:59.730" LastActivityDate="2018-12-07T08:33:59.730" Title="Lightning moving close to the ground in Magalia, CA last July, months before the Camp Fire" Tags="|fire|" AnswerCount="0" CommentCount="4" ClosedDate="2018-12-29T09:33:48.827" ContentLicense="CC BY-SA 4.0" />
  <row Id="15717" PostTypeId="1" CreationDate="2018-12-07T08:43:10.940" Score="0" ViewCount="127" Body="&lt;p&gt;so this is my first time here because I need help in identifying the features on this rock formation. &#xA;&lt;a href=&quot;https://www.flickr.com/gp/158064920@N05/6USrY9&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.flickr.com/gp/158064920@N05/6USrY9&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you in advance. &lt;/p&gt;&#xA;" OwnerUserId="14471" LastEditorUserId="6258" LastEditDate="2019-01-07T15:24:15.590" LastActivityDate="2019-01-07T15:24:15.590" Title="Need help identifying rock formation" Tags="|geology|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15718" PostTypeId="2" ParentId="15717" CreationDate="2018-12-07T09:38:40.837" Score="1" Body="&lt;p&gt;in picture 11 there is erosion by water and wind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;it is sandstone and this is easily eroded by water each time it rains the water takes particles of the sandstone and moves them down the mountain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;sorry for this short and bad answer,it was a simple question so the answer is simple too.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastActivityDate="2018-12-07T09:38:40.837" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15720" PostTypeId="1" CreationDate="2018-12-07T13:10:37.967" Score="5" ViewCount="120" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Aral_Sea&quot; rel=&quot;nofollow noreferrer&quot;&gt;Aral Sea&lt;/a&gt; was a major lake of the USSR until it suffered artificial changes, which began sometime no later than the 1960s.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am unfortunately not sure when major artificial changes began. Wikipedia says that canal construction &quot;on a large scale&quot; began in the 40's, but then mentioned &quot;By 1960, between 20 and 60&quot; cubic km of water was being diverted. So it appears the date I'm looking for is somewhere between 1940 and 1960.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyway, the two key figures I'm interested in are &lt;strong&gt;average depth&lt;/strong&gt; and &lt;strong&gt;salinity&lt;/strong&gt;. What were these in the Aral Sea before it changed? One reason I ask is I'm especially curious if it was just a smaller version of the Caspian.&lt;/p&gt;&#xA;" OwnerUserId="2733" LastEditorUserId="18081" LastEditDate="2022-08-04T08:38:22.340" LastActivityDate="2022-08-04T08:38:22.340" Title="Before the artificial changes of the Aral Sea, what was its average depth and salinity?" Tags="|geography|salinity|lakes|bathymetry|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15721" PostTypeId="2" ParentId="15711" CreationDate="2018-12-07T14:10:33.510" Score="4" Body="&lt;p&gt;The water year does vary depending on the region, for example in Australia the water year begins on &lt;a href=&quot;http://www.bom.gov.au/water/awid/id-644.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;July 1&lt;/a&gt;. I am not sure about other regions, I believe the October 1st water year is quite standard across the northern hemisphere although may shift as you go far north to polar and more arid climates. I would recommend searching for similar links to the one for Australia to find the government defined water year, if it exists in your region of interest.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The purpose of the water year is to use, in lamens terms, the least exciting hydrologic time of year to avoid missing large events or fluxes based on the start time of simulation or data consideration, so depending on the annual hydrologic patterns in the given region shifting the water year start generally makes sense. For this reason as well, the calendar year is generally a bad idea for hydrologic models or data considerations, since you are then starting during a time of accumulated snowpack and can have mid-winter melts around that time (at least in the northern hemisphere, generally speaking).&lt;/p&gt;&#xA;" OwnerUserId="8440" LastActivityDate="2018-12-07T14:10:33.510" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15722" PostTypeId="2" ParentId="15705" CreationDate="2018-12-07T14:18:45.243" Score="-2" Body="&lt;p&gt;According to google, granite is an igneous rock. And as I said in my comment, it has several different other minerals that are formed within it, such as quartz or feldspar.&lt;/p&gt;&#xA;&lt;p&gt;Some people may tell you that granite is a sedimentary rock, but based on the way it is formed (by magma cooling beneath the earths' surface) it is considered    an igneous rock.&lt;/p&gt;&#xA;&lt;p&gt;More information at &lt;a href=&quot;https://geology.com/rocks/granite.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;geology.com&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="12057" LastEditorUserId="-1" LastEditDate="2021-09-28T22:30:29.190" LastActivityDate="2021-09-28T22:30:29.190" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15723" PostTypeId="2" ParentId="6527" CreationDate="2018-12-07T19:20:25.193" Score="2" Body="&lt;p&gt;The assumption that 15,000 km3 is melted in one year is not correct. This is approximately the amount that will melt in the melt-season. In the winter it will grow back again. Check PIOMAS website for the correct values: &lt;a href=&quot;http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://psc.apl.uw.edu/research/projects/arctic-sea-ice-volume-anomaly/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;To melt the additional 280 km3 of sea ice, the amount we have been losing on an annual basis based on PIOMAS calculations, it takes roughly 8.6 x 10^19 J&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Thus the imbalance for the sea-ice in the Northern Hemisphere is only 8.6 x 10^19 J&lt;/p&gt;&#xA;&lt;p&gt;**edit 2022 January 5th.&#xA;Now I changed my mind. I'm thinking that global warming is moderated. The melt of 280 km3 is the annual melt, but the last sea-ice of 280km3 will also melt in approximately 2 weeks . Let's assume from September 1st until September 15 th in 2026. Than you have the same imbalance for the sea-ice in the Northern Hemisphere ( &amp;quot;only&amp;quot; 8.6 x 10^19 J ) but only in 2 weeks. That means the radiative forcing in 2 weeks is 52/2= 26 times more than what PIOMAS has calculated for the annual forcing (52 weeks). PIOMAS write on their website:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;It corresponds to about 0.4 Wm-2&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;But this can be 26 x 0.4 = 10.4 Wm-2 in 2 weeks. I'm not sure if this is correctly understand. It will cause a delay in refreezing and this delay will double every year so the sea-ice will disappear within 5 years. To me this looks like a warming phase during a Dansgaard-Oeschger event.&lt;/p&gt;&#xA;" OwnerUserId="14476" LastEditorUserId="106" LastEditDate="2022-01-06T08:38:09.467" LastActivityDate="2022-01-06T08:38:09.467" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15724" PostTypeId="2" ParentId="15705" CreationDate="2018-12-07T23:47:51.143" Score="12" Body="&lt;p&gt;This is the key:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;used to be part&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It is important to look at this in a historical context. Up until the 1950s and early 1960s, there was no agreement to how granites form. This became the &lt;a href=&quot;https://duckduckgo.com/?q=granite%20controversy&amp;amp;t=ffab&amp;amp;ia=web&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;granite controversy&lt;/strong&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;On the one hand, experimental work showed that granites crystallise from magma, but this magma had to be derived from basalt-like magmas. This led to two problems:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Where is all the basalt from which the granite was supposed to form?&lt;/li&gt;&#xA;&lt;li&gt;What happened to all the rock that was there before the granite formed (aka the &amp;quot;room problem&amp;quot;)?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;This led people to think that granites formed by &lt;a href=&quot;https://en.wikipedia.org/wiki/Metasomatism&quot; rel=&quot;nofollow noreferrer&quot;&gt;metasomatic&lt;/a&gt; replacement of other rocks. Essentially, you have other things that were not granite that were transformed to granite through various geological process, without ever crystallising from magmas. This is what people say when they talk about granites as metamorphic rocks.&lt;/p&gt;&#xA;&lt;p&gt;However, this is not the case and later research demonstrated that granites form by crystallisation of magma and the process of metamorphic formation of granites (by metasomatism, or &amp;quot;granitisation&amp;quot;) does not actually exists. There were (and still are) many questions left unanswered on exactly how this happens, but we know granites are indeed igneous rocks. In fact, there's a &lt;a href=&quot;https://doi.org/10.1038/s41586-018-0746-2&quot; rel=&quot;nofollow noreferrer&quot;&gt;great paper&lt;/a&gt; published in Nature, showing modelling of how some of these things can form.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Nevertheless, granite formed can be sometimes related to metamorphism. Extreme cases of hot metamorphic can cause melting of (previously sedimentary and then metamorphic) rocks to form magma that eventually crystallises as granites. This is known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Migmatite&quot; rel=&quot;nofollow noreferrer&quot;&gt;migmatisation&lt;/a&gt;, and is commonly used to explain the widespread occurrence of &amp;quot;leucogranites&amp;quot; in the Himalayas for example.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, some high-grade metamorphic rocks contain quartz, feldspars, micas, and amphiboles. The metamorphic texture (foliation and lineation) is not always obvious, making it easy to mistake metamorphic gneisses as igneous granites.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="2470" LastEditDate="2021-09-29T15:40:48.813" LastActivityDate="2021-09-29T15:40:48.813" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15726" PostTypeId="2" ParentId="15717" CreationDate="2018-12-08T05:51:33.313" Score="0" Body="&lt;p&gt;The rounded gravel was part of a river channel cutting through the sandstone. No faults. You can Google the term channel facies. &lt;/p&gt;&#xA;" OwnerUserId="13398" LastActivityDate="2018-12-08T05:51:33.313" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15729" PostTypeId="1" AcceptedAnswerId="15737" CreationDate="2018-12-08T20:13:29.193" Score="1" ViewCount="1075" Body="&lt;p&gt;We have a well (about 1200KM away from sea and 60 meter deep), the water when taken out has slightly dark color and has smell. But strangely in about 12 hours the smell and black color vanishes and water becomes odorless and clear without leaving any residues.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What can be possible cause, are there any known underground impurities that change with something like sunlight or air exposure?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Organic impurities and sulfides don't disappear like this, can someone help with details of this kind of water impurity.&lt;/p&gt;&#xA;" OwnerUserId="14483" LastEditorUserId="14483" LastEditDate="2018-12-09T13:21:33.427" LastActivityDate="2018-12-09T23:58:36.773" Title="What is the cause of temporary smell and black color of underground water?" Tags="|water|groundwater|underground-water|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15732" PostTypeId="2" ParentId="15717" CreationDate="2018-12-09T07:19:27.193" Score="0" Body="&lt;p&gt;The long vertical lines on &quot;Earth 11&quot; are not joints, but are &lt;a href=&quot;https://en.wikipedia.org/wiki/Rill&quot; rel=&quot;nofollow noreferrer&quot;&gt;rills&lt;/a&gt;. As water flows across the surface and becomes turbulent, it picks up the unprotected sediment and carries it off. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is no reason to believe that &quot;Earth 13&quot; is a fault, unless you found slickenlines or other fault features. The overlying rock is indeed a &lt;a href=&quot;https://en.wikipedia.org/wiki/Conglomerate_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;conglomerate&lt;/a&gt; (specifically an orthoconglomerate), and the rock below appears to be a sandstone. It's hard to say if the contact is conformable or not, but the gap between the two rocks probably doesn't represent a huge amount of time. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Such deposits are similar in &lt;a href=&quot;https://en.wikipedia.org/wiki/Fluvial_processes&quot; rel=&quot;nofollow noreferrer&quot;&gt;fluvial&lt;/a&gt; settings. Basically, as a river meanders back and forth, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Stream_capacity&quot; rel=&quot;nofollow noreferrer&quot;&gt;stream capacity&lt;/a&gt; is always in flux. That means there are times when the river is eroding, and there are times when the river is depositing sediment. The sandstone was probably deposited on a &lt;a href=&quot;https://en.wikipedia.org/wiki/Point_bar&quot; rel=&quot;nofollow noreferrer&quot;&gt;point bar&lt;/a&gt; in slower moving water than the conglomerate, which was deposited by faster moving water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In summary: &lt;strong&gt;this formation is probably the result of a paleoriver&lt;/strong&gt;. Rounded conglomerates, such as the one in the image, are typical of fluvial deposits. (Angular conglomerates usually have different depositional settings). Alternating packages of siltstone, sandstone, and conglomerate are also typical of fluvial deposits&lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS - I'm a licensed geologist, so I like to think I know what I'm talking about.&lt;/p&gt;&#xA;" OwnerUserId="8472" LastActivityDate="2018-12-09T07:19:27.193" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15734" PostTypeId="1" CreationDate="2018-12-09T14:24:48.043" Score="5" ViewCount="157" Body="&lt;p&gt;I'm trying to understand/reproduce/revise this chart in the &lt;a href=&quot;https://nca2018.globalchange.gov/chapter/19/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Southeast section&lt;/a&gt; of the United States &lt;a href=&quot;https://nca2018.globalchange.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Climate Assessment&lt;/a&gt;. The truncated scale for the bars is what caught by eye as a classic &lt;a href=&quot;https://callingbullshit.org/tools/tools_misleading_axes.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;chart lie&lt;/a&gt;, but I'm also wondering about other features: different thresholds (besides 3 inches) and different aggregations (besides decades).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PkFz1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PkFz1.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Original caption for this chart plus a map next to it:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Figure 19.3: The figure shows variability and change in (left) the&#xA;  annual number of days with precipitation greater than 3 inches&#xA;  (1900–2016) averaged over the Southeast by decade and (right)&#xA;  individual station trends (1950–2016). The number of days with heavy&#xA;  precipitation has increased at most stations, particularly since the&#xA;  1980s. Sources: NOAA NCEI and CICS-NC.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The vague source citations are not particularly helpful, but I did find NOAA's &lt;a href=&quot;https://www.ncdc.noaa.gov/ghcnd-data-access&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Historical Climatology Network Daily&lt;/a&gt; downloadable data. That has daily precipitation data for 100,000 stations around the world, with about 12,000 in the Southeast. However, in a given year, I'm seeing 100 to 200 days with precipitation above 3 inches, but the chart indicates a different order of magnitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What does &quot;days with precipitation greater than 3 inches&quot; mean in this context?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm guessing there must be a &quot;per station&quot; part to it, but I still can't guess the exact math. The simplest treatment, a weighted average of each stations rate of heavy rain, produces the chart below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1LWf4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1LWf4.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's close (same order of magnitude and peaks in 40s, 70s and recent), but not quite the same. Is there a different data source? Or a different treatment for irregular samples? Or a way to account for increasing number of stations?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Update after comments:&lt;/strong&gt;&#xA;If I filter on stations with at least 110 years of data and use only years with 200+ days of data, I get the following, which is closer. (Using the same scale as the original, but avoiding bar truncation by just showing the tops.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pSi3N.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pSi3N.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most decades have lower values than the original.&lt;/p&gt;&#xA;" OwnerUserId="14486" LastEditorUserId="14486" LastEditDate="2018-12-12T23:24:38.040" LastActivityDate="2018-12-16T20:50:14.210" Title="How is heavy rainfall determined in National Climate Assessment" Tags="|climate|precipitation|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="15735" PostTypeId="1" CreationDate="2018-12-09T18:07:18.353" Score="3" ViewCount="41" Body="&lt;p&gt;Sedimentary rock phosphates contain much higher concentrations of potentially hazardous elements (As, Cd, Cr,Pb, Se and U)than igneous rock phosphates. Why?&#xA;Is it because U concentration in magmatic water is lower than in ocean water?&#xA;how could U accomodate in the apatite of igneous?&lt;/p&gt;&#xA;" OwnerUserId="12361" LastActivityDate="2018-12-09T18:07:18.353" Title="why igneous phosphate rocks contain less uranium than sedimentary rocks?" Tags="|geology|geochemistry|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15737" PostTypeId="2" ParentId="15729" CreationDate="2018-12-09T23:58:36.773" Score="2" Body="&lt;p&gt;This is due to the presence of iron sulfide in the water. The iron sulfide oxidizes and goes into solution. Ferrous iron oxidizes to ferric iron. Depending on the water chemistry, this commonly precipitates out as orange-coloured iron oxyhydroxide, but that does not seem to be occuring in your case, otherwise you would see it. When it does happen, the pH of the water drops, as seen in acid mine drainage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sulfide may be volatilized as hydrogen sulfide which smells, or it too may oxidize and volatilize as sulfur dioxide (rotten egg smell). It can continue to oxidize to sulfate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The iron sulfide may be present in the aquifer or it may be formed by microbial activity in your well. In the latter case, treating the well with bleach can solve the problem, at least temporarily. Be sure to treat all the piping, too. If possible, install a backflow preventer so water doesn't flow back down the well.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2018-12-09T23:58:36.773" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15738" PostTypeId="1" CreationDate="2018-12-10T01:57:39.147" Score="1" ViewCount="51" Body="&lt;p&gt;Soil testing from a well-drained soil sample in 0-15cm depth of a farmers field provides the following&#xA;information:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;• Wet weight of a soil sample from a volume of 100 &lt;span class=&quot;math-container&quot;&gt;$cm^3$&lt;/span&gt;: 200 g&lt;/p&gt;&#xA;&#xA;&lt;p&gt;• Moisture content: 20%&lt;/p&gt;&#xA;&#xA;&lt;p&gt;• Soil chemical properties (in cmol/kg):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Exchangeable K: 2&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Exchangeable Ca : 10&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Exchangeable Mg: 4&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Exchangeable H: 8&lt;/p&gt;&#xA;&#xA;&lt;p&gt;• Molar mass of &lt;span class=&quot;math-container&quot;&gt;$H^+$&lt;/span&gt;= 1; &lt;span class=&quot;math-container&quot;&gt;$Mg^2$$^+$&lt;/span&gt; = 24; &lt;span class=&quot;math-container&quot;&gt;$K^+$&lt;/span&gt;&#xA; = 39; &lt;span class=&quot;math-container&quot;&gt;$Ca^2$&lt;/span&gt;+ = 40&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1.What is the bulk density of this soil?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;in here i did MS=(W-D)/W=0.2=(200-D)/200 SO Dry soil =160, Bulk density =160/100=1.6&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2.How many kg &lt;span class=&quot;math-container&quot;&gt;$ha^-$$^1$&lt;/span&gt; of exchangeable &lt;span class=&quot;math-container&quot;&gt;$Mg^2$$^+$&lt;/span&gt; is there in the top 15cm of this field?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have no idea about this question &lt;/p&gt;&#xA;&#xA;&lt;p&gt;3.What is the percent base saturation? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;i dont know hot to get the total CEC in this question&lt;/p&gt;&#xA;" OwnerUserId="14491" LastEditorUserId="14491" LastEditDate="2018-12-10T02:18:31.073" LastActivityDate="2018-12-10T02:18:31.073" Title="How many kg $ha^-$$^1$ of exchangeable $Mg^2$$^+$ is there in the top 15cm of this field?" Tags="|soil|earth-system|soil-moisture|soil-science|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15739" PostTypeId="2" ParentId="15709" CreationDate="2018-12-10T02:49:31.667" Score="3" Body="&lt;p&gt;After a more elaborate literature survey, it turns out that there are two types of quality control that can be performed on seismic data. One is of the acquisition parameters [1], which are just a few bytes per minute. Meanwhile, in [2], the entire data can be screened through QC software before being sent to a central server. This would help report errors in the acquisition process before conducting further sweeps.&lt;/p&gt;&#xA;" OwnerUserId="11056" LastActivityDate="2018-12-10T02:49:31.667" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15741" PostTypeId="2" ParentId="10800" CreationDate="2018-12-10T08:44:46.523" Score="-3" Body="&lt;p&gt;Every time the rays of the sun come into contact with earth they have to first be reflected back to the ozone layer before returning to earth. This has a cooling effect on the earth temperature. Since the industrial revolution the ozone layer has been severely depleted by the greenhouse gas emissions. Remember the sun is a ball of burning gases, whose light reaches earth early morning within eight minutes. If the earth just moved an inch away in space from the position set approximately from the sun, earth could freeze and no living organism would survive. In the same regard if it moved an inch closer to the sun every life would be incinerated. &lt;/p&gt;&#xA;" OwnerUserId="14493" LastActivityDate="2018-12-10T08:44:46.523" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15743" PostTypeId="1" AcceptedAnswerId="15745" CreationDate="2018-12-10T16:44:05.580" Score="6" ViewCount="194" Body="&lt;p&gt;Whats the largest earthquake since 1900 that was not in a subduction zone (not a megathrust).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wikipedia says that Since 1900, all earthquakes of magnitude 9.0 or greater have been megathrust earthquakes. No other type of known terrestrial source of tectonic activity has produced earthquakes of this scale.&lt;/p&gt;&#xA;" OwnerUserId="6615" LastActivityDate="2018-12-10T21:24:16.993" Title="largest earthquake not in a subduction zone" Tags="|earthquakes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15745" PostTypeId="2" ParentId="15743" CreationDate="2018-12-10T21:24:16.993" Score="6" Body="&lt;p&gt;08/15/1950 Assam, tibet, 8.9 magnitude. according to the USGS, &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/browse/largest-world.php&quot; rel=&quot;noreferrer&quot;&gt;https://earthquake.usgs.gov/earthquakes/browse/largest-world.php&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note you are talking about a very small window of time there are only 5 earthquakes of 9.0 or greater within that time frame. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2018-12-10T21:24:16.993" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="15746" PostTypeId="1" CreationDate="2018-12-10T22:09:58.390" Score="3" ViewCount="414" Body="&lt;p&gt;My understanding of the LAB is that it represents the point in the earth where the mantle undergoes a temperature activated mechanical change. The temperature of the boundary depends on the melting point of the mantle and so one could say that the LAB is an isotherm with temperature given by:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$T=kT_m,$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$T_m$&lt;/span&gt; is the melting point of the mantle and &lt;span class=&quot;math-container&quot;&gt;$k$&lt;/span&gt; is some constant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is how I have had the situation explained to me, and in sources that I have read that the LAB is an isotherm at &lt;span class=&quot;math-container&quot;&gt;$\pu{1300 ^\circ C}$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My only problem with this is that surely &lt;span class=&quot;math-container&quot;&gt;$T_m$&lt;/span&gt; changes with depth, and therefore the Lithosphere-Asthenosphere boundary is not an isotherm at all, but depends on the depth at which the boundary is at (for example at a mid-ocean ridge where the boundary becomes shallower towards the ridge axis).&lt;/p&gt;&#xA;" OwnerUserId="14502" LastEditorUserId="14566" LastEditDate="2018-12-18T14:02:11.397" LastActivityDate="2018-12-20T17:03:48.097" Title="Why is the Lithosphere-Asthenosphere Boundary an Isotherm?" Tags="|plate-tectonics|mantle|ocean-ridge|lithosphere|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15749" PostTypeId="1" AcceptedAnswerId="16103" CreationDate="2018-12-11T01:47:15.657" Score="4" ViewCount="112" Body="&lt;p&gt;CMIP5 offers natural-forcings-only simulations over 1850-2005, which allows comparison with the historical simulations, which allows us to show how anthropogenic forcings have affected the climate over that time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;CMIP5 also offers projections over the 21st century, with a range of RCPs allowing for different emissions scenarios.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, CMIP5 doesn't include a 21st century natural forcing for comparison, even though this would be useful. &lt;strong&gt;Do such simulations exist&lt;/strong&gt; anywhere else?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I realise that these would not be perfectly possible, since data for natural forcings like volcanoes are not available. However, these might be reasonably simulated using a stochastic model. Other natural forcings, such as orbital forcings, can be calculated fairly easily over the next century. Solar irradiance probably falls somewhere in between the two.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If such simulations do not exist, &lt;strong&gt;would it be unreasonable to use the 1850-2005 natural forcings simulations as the basis for a statistical model of the 21st century&lt;/strong&gt;? Or are some of the natural forcings likely to change substantially (e.g. are 20th century volcanoes unrepresentative of the background, or is the orbital forcing likely to change substantially over the coming century?).&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2019-01-29T22:50:30.603" Title="Are there natural-forcings climate projections over the 21st century?" Tags="|climate|climate-models|simulation|natural-conditions|" AnswerCount="1" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15751" PostTypeId="2" ParentId="15632" CreationDate="2018-12-11T09:36:50.300" Score="3" Body="&lt;p&gt;One direction to look in might be the various GIS systems that exist to forecast the amount of light that will reach photovoltaic (solar panel) installations. I don't know about the US, but I would be very surprised if there isn't one - try googling for &quot;PV GIS&quot; or similar.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, that will give you insolation (illuminance) in W/m&lt;sup&gt;2&lt;/sup&gt;. It may be further broken down into direct and indirect insolation (that's direct sunlight and diffuse light from the sky or clouds), or it may be a single global figure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since you're after the information in lux rather than W/m&lt;sup&gt;2&lt;/sup&gt;, you'll need to convert it. This will necessarily be an approximate process, but so long as you don't need very high accuracy it should be quite doable. Lux is at base a measurement of power density, just like W/m&lt;sup&gt;2&lt;/sup&gt;, but it's modified by a &lt;a href=&quot;https://en.wikipedia.org/wiki/Luminosity_function&quot; rel=&quot;nofollow noreferrer&quot;&gt;frequency-dependent function&lt;/a&gt; that represents the sensitivity of human vision. So you'll need to assume a spectrum for the sunlight, and then apply the conversion curve (which is an international standard, and hopefully available on the internet).&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2018-12-11T09:36:50.300" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15752" PostTypeId="1" CreationDate="2018-12-11T12:03:13.200" Score="3" ViewCount="32" Body="&lt;p&gt;What is the timing of the rise of the Andes, especially if focused on the chronosequence differences among (Western, Central, Eastern) Cordilleras uplift.&lt;/p&gt;&#xA;" OwnerUserId="14509" LastEditorUserId="595" LastEditDate="2018-12-11T14:55:11.147" LastActivityDate="2018-12-11T14:55:11.147" Title="Ages of the Andean Cordilleras" Tags="|time|geochronology|mountain-building|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15754" PostTypeId="1" CreationDate="2018-12-11T17:22:54.917" Score="8" ViewCount="264" Body="&lt;p&gt;I have recently watched the documentary &amp;quot;&lt;a href=&quot;https://www.imdb.com/title/tt1575870/&quot; rel=&quot;nofollow noreferrer&quot;&gt;How Many People Can Live on Planet Earth?&lt;/a&gt;&amp;quot; with &lt;a href=&quot;https://en.wikipedia.org/wiki/David_Attenborough&quot; rel=&quot;nofollow noreferrer&quot;&gt;David Attenborough&lt;/a&gt;. In it, the main factors that will limit total human population Earth can support are named. One of these was the limited amount of fresh water. There also was a part where it described how fresh water is distilled from astronaut urine on the &lt;a href=&quot;https://en.wikipedia.org/wiki/International_Space_Station&quot; rel=&quot;nofollow noreferrer&quot;&gt;International Space Station&lt;/a&gt;  .&lt;/p&gt;&#xA;&lt;p&gt;My current understanding is that all the water (fresh or not) in nature (i.e. on planet Earth) is infinitely going through a &lt;a href=&quot;https://en.wikipedia.org/wiki/Water_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;water cycle&lt;/a&gt;, and thus non-fresh water is sort of &lt;a href=&quot;https://en.wikipedia.org/wiki/Distillation&quot; rel=&quot;nofollow noreferrer&quot;&gt;distilled&lt;/a&gt; into fresh by this natural process.&lt;/p&gt;&#xA;&lt;p&gt;My questions are:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Where am I wrong in my assumption about natural water distillation (i.e. is rain water not as clean as it should be in theory)?&lt;/li&gt;&#xA;&lt;li&gt;Why don't we collect rain water (at least for plant watering, if it is not suitable for drinking)?&lt;/li&gt;&#xA;&lt;li&gt;Theoretically, after an animal has consumed some amount of water, say a glass, how long will it take, after that animal urinates on the ground, for that water to go through the water cycle and become ready for drinking again?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerDisplayName="user14513" LastEditorUserId="6467" LastEditDate="2020-11-21T00:11:15.123" LastActivityDate="2020-11-21T00:11:15.123" Title="Aren't fresh water deposits renewed by the water cycle?" Tags="|water|human-influence|ecology|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15755" PostTypeId="2" ParentId="15754" CreationDate="2018-12-11T19:37:19.043" Score="2" Body="&lt;p&gt;Rain water is still one of the most cleanest water sources available. There may be some ancient underground aquifers that have clean uncontaminated water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One issue with rain water is that atmospheric moisture - part of the water cycle - needs to condense on aerosols in the atmosphere before it can develop into rain. With the amount of pollution humans are dumping into the atmosphere some of that can form the aerosols that eventually develops into rain thus making rain water dirtier than it used to be - such as &lt;a href=&quot;http://paos.colorado.edu/~fasullo/1060/aerosols/aeroimp.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;acid rain&lt;/a&gt; being formed when sulfur dioxides are dumped into the atmosphere when high sulfur coal is burned in power stations. Other aerosols include &lt;a href=&quot;http://www.homepages.ed.ac.uk/shs/Climatechange/Data%20sources/Jensen%20marine%20cloud%20aerosol.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;salt from the oceans&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other issue with rain water is that the soil in water catchments can be contaminated by pollution. Rain falling on the catchments can absorb some of the contaminants thus making the rain water in the resultant catchment dirtier that it might have been in the past.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding the rate of urine production of animals, it depends on the type of animal. A mouse will process water at a different rate to an elephant or domestic live stock. It is also influenced by circadian rhythms for each type of animal.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-12-11T19:37:19.043" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15759" PostTypeId="2" ParentId="15754" CreationDate="2018-12-12T07:38:25.810" Score="1" Body="&lt;p&gt;The problem about rain water catchment is, that it prevents ground water from being formed, thus depleting these ressources and making them unavailable during droughts. Plus, ground water tends to be cleaner than rain water as far as I know - provided there's no fracking or subterranean atomic waste storage around.&lt;/p&gt;&#xA;" OwnerUserId="14194" LastActivityDate="2018-12-12T07:38:25.810" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15761" PostTypeId="1" CreationDate="2018-12-12T10:01:38.703" Score="1" ViewCount="73" Body="&lt;p&gt;I have read many articles and each has a own specific view, how we can calculate monsoon onset (for example Indian summer monsoon onset) in simple way? &#xA;Can any one make me understand in simple way?&#xA;It would be pleasure if most suitable required dataset also mention.&#xA;Note; I am interested in interannual and seasonal migration of monsoon onset for south asia only.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank in advance&lt;/p&gt;&#xA;" OwnerUserId="12714" LastActivityDate="2018-12-12T10:01:38.703" Title="How to calculate monsoon onset?" Tags="|monsoon|" AnswerCount="0" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="15765" PostTypeId="1" CreationDate="2018-12-13T06:50:44.713" Score="4" ViewCount="128" Body="&lt;p&gt;Overland oil spills are fairly common, so Earth arguably has some transient hydrocarbon lakes. &lt;a href=&quot;https://www.capjournal.com/news/years-later-cleanup-nears-end-for-big-north-dakota-spill/article_a8b20366-9e81-11e7-aeee-6f09e39894d3.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;One incident&lt;/a&gt; in 2013 dumped nearly 1 million gallons of oil over North Dakota, covering 13 acres of land. A very different type of hydrocarbon lake is &lt;a href=&quot;https://en.wikipedia.org/wiki/Lakes_of_Titan&quot; rel=&quot;nofollow noreferrer&quot;&gt;found on Titan&lt;/a&gt;, the only Solar System moon with surface oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does Earth have any stable bodies of liquid, that are not liquid water? Let's limit this to the surface, and exclude anything that is more than &gt;50% H2O by mass.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only example I can think of, besides petroleum spills, is lava lakes. However, I'm not sure if these are truly stable, or if it's even appropriate to call lava a liquid instead of a plastic. Maybe in the past, for example during Snowball Earth, climate conditions were more appropriate for non-water lakes forming from atmospheric volatiles.&lt;/p&gt;&#xA;" OwnerUserId="12912" LastActivityDate="2018-12-13T06:50:44.713" Title="Does Earth have any stable bodies of liquid, that are not liquid water?" Tags="|petroleum|lakes|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15768" PostTypeId="1" CreationDate="2018-12-14T00:26:18.070" Score="1" ViewCount="153" Body="&lt;p&gt;I have compiled Calpuff and mmif, hence Calmet it is not necessary because I create the Calmet output from WRF using mmif. Now I only need to create the emission inputs files. According to calpuff.inp, the emission inputs files are:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Emission Files&#xA;PTEMARB.DAT input * PTDAT   = *&#xA;VOLEMARB.DAT input * VOLDAT = *&#xA;BAEMARB.DAT input * ARDAT   = *&#xA;LNEMARB.DAT input * LNDAT   = *&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;How do I generate this files? &#xA;I've navigated into the calpuff.for file but I still cant find the proper Fortran format.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="6489" LastActivityDate="2018-12-14T00:26:18.070" Title="How do I generate the emission sources for calpuff (SRC)?" Tags="|emissions|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15769" PostTypeId="2" ParentId="2814" CreationDate="2018-12-14T04:32:28.600" Score="-1" Body="&lt;p&gt;I think it would be have to be air tight I'm trying my own theory out but much smaller. I'm gonna try out how the flat earth idea is where there is water above.&#xA;So basically the idea is I'm gonna put a plant in dirt alive an growing inside a glass sphere that's round along with the needed gases. And submerge it under water if nothing happens after so long I'll put bugs inside if nothing else happens then something bigger an so on n so forth. &lt;/p&gt;&#xA;" OwnerUserId="14534" LastActivityDate="2018-12-14T04:32:28.600" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15770" PostTypeId="1" CreationDate="2018-12-14T20:23:25.577" Score="5" ViewCount="379" Body="&lt;p&gt;I have no expertise in geology or earth science, but I would like to do a &quot;field trip&quot; with my home-schooled young children (under age 10) where I could teach them about geology from a hands-on perspective.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What could I do on this field trip that would make this event memorable and special for the children, that would not be possible just at home at the dining table?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are unfamiliar with small children, here are some outside things they like to do that I think may be compatible with this kind of event:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;digging (and hopefully finding pretty rocks, crystals, fossils, etc)&lt;/li&gt;&#xA;&lt;li&gt;hiking, walking, and running&lt;/li&gt;&#xA;&lt;li&gt;exploring &quot;the wild&quot;&lt;/li&gt;&#xA;&lt;li&gt;caves&lt;/li&gt;&#xA;&lt;li&gt;creatures&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I had a few ideas, but I don't know if any of them are practical or possible, or where I could gain the skills to make these really happen?&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Use our knowledge of geology to predict what kind of rocks we'd find if we dug in one place. Go there and dig, and see if we are right.&lt;/li&gt;&#xA;&lt;li&gt;Somehow actually find something that is uncommon: iron, shark teeth, crystals&lt;/li&gt;&#xA;&lt;li&gt;Find an area with 2-3 distinct kinds of rock, so it is very easy for the kids to distinguish this sedimentary rock over here from that igneous rock over there.&lt;/li&gt;&#xA;&lt;li&gt;Bring back something that would be more interesting when viewed under a microscope&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;I would hope that any answers could be generally applied anywhere, but if it is helpful I live on the Wasatch Front in Utah, USA&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="14536" LastActivityDate="2018-12-18T20:07:12.957" Title="Making a local geological field trip an interesting and educational event for children?" Tags="|geology|rocks|soil|education|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15771" PostTypeId="2" ParentId="15770" CreationDate="2018-12-14T22:26:44.717" Score="7" Body="&lt;p&gt;You live in an very good state for interesting geology, rock collecting, etc.  In regards to looking for things the kids can collect, view and otherwise analyse the PDF, &quot;&lt;a href=&quot;https://ugspub.nr.utah.gov/publications/misc_pubs/MP-95-4.pdf&quot; rel=&quot;noreferrer&quot;&gt;The Collectors Guide to Rocks, Minerals, and Fossil Localities of Utah&lt;/a&gt;&quot; would be a good start to your research.  The publication is from the Utah government and covers a large number of areas in the state.  Over 30 years ago I made a trip to the Caineville just east of Capital Reef National Monument and collected pelecypods, they where laying on the soil with the occasional gypsum spars.  I believe the area is in the document I suggest you read, I doubt I could find it now but there was lots to find in the area in general including some evaporative type minerals, agates, and fossils.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You also have the Great Salt Lake, some areas would be good to collect and view brine shrimp, protozoa, and algae with a microscope, many would be easily viewable with a dissecting microscope.  You could also discuss the geological history of lake Bonneville of which the Great Salt Lake is but a remnant.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally the &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/1889786373&quot; rel=&quot;noreferrer&quot;&gt;Gem Trails of Utah&lt;/a&gt; guide can provide some sites where collecting might be appropriate, though this publication is getting old and doesn't focus much on geology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The land status and access to these areas change frequently and sometimes it is difficult to locate the sites, expect some failures in your adventures.  I would also suggest that you field check the surrounding areas because published areas often get damaged by careless individuals.  Finally, would also suggest you follow &lt;a href=&quot;https://lnt.org/&quot; rel=&quot;noreferrer&quot;&gt;leave no trace principals&lt;/a&gt; as much as possible within a collecting trip, the scenery and wildlife in many of these areas are really impressive and it is a shame to see it all dug up by collectors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a final thought most states have some form of Geological Road Maps, there are some listed on this &lt;a href=&quot;https://geology.utah.gov/popular/places-to-go/geologic-guides/&quot; rel=&quot;noreferrer&quot;&gt;government site&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2018-12-14T22:26:44.717" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15773" PostTypeId="2" ParentId="15770" CreationDate="2018-12-15T03:37:31.843" Score="1" Body="&lt;p&gt;Some road cuts are interesting to look at.  When a cut exposes several obviously different layers of rock, you can see differences in texture, layer thickness, and so forth.  They also convey very clearly the concept of rock being deposited in layers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You'll need to do some scouting, though -- some cuts are boring (only one kind or rock exposed), and some have other problems, like no safe way to get off the road or poison oak between the road and rock face.&lt;/p&gt;&#xA;" OwnerUserId="14539" LastActivityDate="2018-12-15T03:37:31.843" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15774" PostTypeId="1" CreationDate="2018-12-15T19:27:20.347" Score="5" ViewCount="296" Body="&lt;p&gt;I'm currently at COP24 (United Nations Climate Change Conference) in Katowice, Poland.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kjzXY.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kjzXY.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;(some editing since I took a screenshot of my laptop)&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;I've asked some guys about &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; emissions but very few have sufficient technical knowledge.&lt;/p&gt;&#xA;&lt;p&gt;My assumption is that they assume the data is right.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Some Google-fu:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://ourworldindata.org/co2-and-other-greenhouse-gas-emissions#how-do-we-measure-or-estimate-co2-emissions&quot; rel=&quot;noreferrer&quot;&gt;https://ourworldindata.org/co2-and-other-greenhouse-gas-emissions#how-do-we-measure-or-estimate-co2-emissions&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;More recent energy statistics are sourced from the UN Statistical Office, which compiles data from official national statistical publications and annual questionnaires.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.thenakedscientists.com/articles/questions/how-do-you-measure-carbon-dioxide-emissions&quot; rel=&quot;noreferrer&quot;&gt;https://www.thenakedscientists.com/articles/questions/how-do-you-measure-carbon-dioxide-emissions&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Intergovernmental Panel on Climate Change has published a five-volume set of guidelines that all the countries now use, as part of the UN Framework Convention on climate change, for estimating emissions on all greenhouse gases and it does produce uniformity across countries.&lt;/p&gt;&#xA;&lt;p&gt;Although there are some large power plants in which they actually put measurement devices in the smoke stack and can measure the amount of CO2 that comes out, that is unusual.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;About measuring &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; in the atmosphere, we have a satellite for that: &lt;a href=&quot;https://climate.nasa.gov/climate_resources/99/graphic-measuring-carbon-dioxide-from-space/&quot; rel=&quot;noreferrer&quot;&gt;https://climate.nasa.gov/climate_resources/99/graphic-measuring-carbon-dioxide-from-space/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;About air quality index - &lt;a href=&quot;https://en.wikipedia.org/wiki/Air_quality_index&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Air_quality_index&lt;/a&gt; - we have a number of standards for that (shame there are multiple standards)&lt;/p&gt;&#xA;&lt;h3&gt;About new &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; emissions - what are the scientific ways to measure that?&lt;/h3&gt;&#xA;" OwnerUserId="14546" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2018-12-19T03:23:29.937" Title="What are the technical solutions to measure $\ce{CO2}$ emissions?" Tags="|measurements|air-pollution|co2|statistics|air-quality|" AnswerCount="4" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15775" PostTypeId="2" ParentId="15774" CreationDate="2018-12-16T13:01:03.463" Score="3" Body="&lt;p&gt;In addition to satellite measurements of carbon dioxide, there are numerous ground based stations that also measure carbon dioxide: &lt;a href=&quot;http://oasi.rse-web.it/index.php/the-network-for-background-co2-measurement-in-italy/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Italy&lt;/a&gt;, &lt;a href=&quot;https://www.esrl.noaa.gov/gmd/ccgg/trends/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hawaii&lt;/a&gt;, &lt;a href=&quot;https://www.csiro.au/en/Research/OandA/Areas/Assessing-our-climate/Greenhouse-gas-data&quot; rel=&quot;nofollow noreferrer&quot;&gt;Australia&lt;/a&gt;, just to name a few.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to catch carbon dioxide emitting cheaters, a dense network of such ground based stations would be needed around the world. The measurements would need to combined with meteorological data, particularly wind directions and strength. I imagine this would also require significant computer modelling to analyze all this data in a timely manner. This would need to be operated by a totally independent organization with lots of money. This will be difficult to achieve.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alternatively, and probably more costly would be to have a constellation of satellites in geostationary orbit around the Earth constantly measuring atmospheric concentrations of carbon dioxide. As with the ground based stations, the data would need to be combined with meteorological data and processed via a computer model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Monitoring compliance will not be cheap or easy.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-12-16T13:01:03.463" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15776" PostTypeId="2" ParentId="15774" CreationDate="2018-12-16T15:52:01.230" Score="2" Body="&lt;p&gt;There is an EU programme having exactly this aim. See &lt;a href=&quot;https://atmosphere.copernicus.eu/european-unions-copernicus-programme-planning-monitoring-capacity-anthropogenic-co2-emissions&quot; rel=&quot;nofollow noreferrer&quot;&gt;this press release&lt;/a&gt;. Monitoring anthropogenic CO2 emissions needs the combination of in-situ measurements, satellite observations and modelling of both the atmosphere and biosphere. &lt;/p&gt;&#xA;" OwnerUserId="13524" LastActivityDate="2018-12-16T15:52:01.230" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15779" PostTypeId="2" ParentId="15734" CreationDate="2018-12-16T20:50:14.210" Score="2" Body="&lt;p&gt;After contacting the author of the chart, I believe the following defines the process behind the chart.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Data source: NOAA's &lt;a href=&quot;https://www.ncdc.noaa.gov/ghcnd-data-access&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Historical Climatology Network Daily&lt;/a&gt; station data for &quot;PCPT&quot;.&lt;/li&gt;&#xA;&lt;li&gt;Use only stations in the Southeast states which have data for 90% of days from 1895 to 2011, to match stations used previous edition of the climate report.&lt;/li&gt;&#xA;&lt;li&gt;Use only years with at least 300 days of data.&lt;/li&gt;&#xA;&lt;li&gt;Remove data values that have been flagged in GHND for quality issues.&lt;/li&gt;&#xA;&lt;li&gt;Count the number of days of heavy rainfall (3 or more inches) for each station and year.&lt;/li&gt;&#xA;&lt;li&gt;Using a 1° by 1° lat/lon grid, average counts of stations in the same grid cell.&lt;/li&gt;&#xA;&lt;li&gt;Report the average of all grid cell-years for a given decade.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I have still not been able to reproduce the chart because I have had trouble getting clean data. Will update with a chart when that happens.&lt;/p&gt;&#xA;" OwnerUserId="14486" LastActivityDate="2018-12-16T20:50:14.210" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15780" PostTypeId="2" ParentId="15774" CreationDate="2018-12-16T22:07:54.647" Score="2" Body="&lt;p&gt;I'll add to Freds answer and just provide some detail about the satellite measurements:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The keyword you're looking for is &quot;remote sensing of the atmosphere&quot; or &quot;remote sensing of XYZ&quot;, where XYZ is any chemical. As with many things scientific in google, you need to know the right keyword to be able to look for them, maybe that's why you didn't get convincing google results.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So as Fred already said, ground stations measure the ground concentrations of &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt;. For satellite observations one measures the intensity of infrared radiation &lt;span class=&quot;math-container&quot;&gt;$I(z)$&lt;/span&gt; in a absorption band that is unique to the chemical of interest, i.e. &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt;, that has a laboratory-known opacity &lt;span class=&quot;math-container&quot;&gt;$\kappa$&lt;/span&gt;. Opacity is just a measure for the intransparency of a gaseous medium, also giving rise to the word 'opaque'. The background intensity &lt;span class=&quot;math-container&quot;&gt;$I_0$&lt;/span&gt; can be determined in a non-absorbing band, or 'atmospheric window' by the same measurment.&lt;br&gt;&#xA;We then know from the radiative transfer equation the following relation:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ I(z) = I_0 \, \exp\left(-\int dz \, \rho(z) \, \kappa \right) $$&lt;/span&gt;&#xA;which contains the unknown density profile &lt;span class=&quot;math-container&quot;&gt;$\rho(z)$&lt;/span&gt; in &lt;span class=&quot;math-container&quot;&gt;$[\rho]=\frac{kg}{m^3}$&lt;/span&gt;, and the integral over it over the atmospheric profile &lt;span class=&quot;math-container&quot;&gt;$dz$&lt;/span&gt;. To solve this one, requires modeling of the profile, but there's an approximation to this, which can give us the column density &lt;span class=&quot;math-container&quot;&gt;$\Sigma$&lt;/span&gt; of a chemical, with &lt;span class=&quot;math-container&quot;&gt;$[\Sigma] = \frac{kg}{m^2}$&lt;/span&gt;, and the approximation is&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ I(z) = I_0 \, \exp\left(-\Sigma \kappa \right), $$&lt;/span&gt;&lt;br&gt;&#xA;which is straightforward to invert and determine &lt;span class=&quot;math-container&quot;&gt;$\Sigma$&lt;/span&gt;. Then one simply plots &lt;span class=&quot;math-container&quot;&gt;$\Sigma$&lt;/span&gt; distributed over the globe, and in this way one can find the emission regions of any chemical, or other interesting things like the Ozone hole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So those measurements are really simple and therefore easily replicable by any satellite or lab around the globe. So if you're worried about governments interfering with this, then the answer is 'that would be obvious'.&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="13524" LastEditDate="2018-12-17T15:20:10.437" LastActivityDate="2018-12-17T15:20:10.437" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15781" PostTypeId="1" CreationDate="2018-12-17T00:40:16.517" Score="2" ViewCount="341" Body="&lt;p&gt;I'm pretty sure metal loses more of its structure as it heats up, so...how does the difference in rotation of Earth's liquid inner and outer core generate any kind of magnetic field? Why wouldn't the magnetic field be even stronger if those two layers weren't rotating?&lt;/p&gt;&#xA;" OwnerUserId="14554" LastEditorUserId="14554" LastEditDate="2018-12-17T03:25:15.627" LastActivityDate="2018-12-17T19:13:12.220" Title="How does liquid iron create a magnetic field?" Tags="|geomagnetism|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15783" PostTypeId="2" ParentId="14451" CreationDate="2018-12-17T05:35:43.797" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Why are these patterns of scattered sunlight aligned to the local horizontal and vertical directions?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The answer can be found in The New York Times article &lt;a href=&quot;https://www.nytimes.com/2017/01/06/science/light-pillars.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Light Pillars, a Million-Mirror Optical Illusion on Winter Nights&lt;/a&gt; and in The Washington Post's &lt;a href=&quot;https://www.washingtonpost.com/weather/2018/12/10/rare-light-pillars-cast-colorful-columns-into-wisconsins-night-sky/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rare light pillars cast colorful columns into Wisconsin’s night sky&lt;/a&gt; says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;However, that’s just half the story. The formation of light pillars requires hexagonally shaped ice crystals in the air to reflect the light. Moreover, they have to be oriented horizontally, like flying discs or plates to bounce light back toward the observer. Less-organized orientations can produce sun pillars and halos.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;A more physics-based explanation can be found in &lt;a href=&quot;https://earthscience.stackexchange.com/a/10606/6031&quot;&gt;this answer&lt;/a&gt; to the question &lt;em&gt;Are there measurements or calculations that suggest atmospheric ice plates would be horizontal to within 0.1 degrees?&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;also see Les Cowley's Atmospheric Optics page &lt;a href=&quot;http://www.atoptics.co.uk/halo/dogfm.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sundog formation&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1gaBk.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1gaBk.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/m4Ibm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/m4Ibm.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Also from &lt;a href=&quot;https://twitter.com/TomPurdyWI/status/1071946562144796672&quot; rel=&quot;nofollow noreferrer&quot;&gt;this tweet&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/s4kyU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/s4kyU.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2020-06-28T02:45:02.513" LastActivityDate="2020-06-28T02:45:02.513" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15786" PostTypeId="1" AcceptedAnswerId="15789" CreationDate="2018-12-17T18:11:19.470" Score="9" ViewCount="208" Body="&lt;p&gt;McMurdo Station in Antartica (operated by the USA) is 77.85 degrees south (and 166.69 east), Longyearbyen (Norway) is the northernmost settlement with scheduled flights all year at 78.24 degrees north (and 15.47 east).&lt;br&gt;&#xA;Longyearbyen is further north than McMurdo is south, but McMurdo rarely receives flights in winter, and seems to be a much more hostile environment overall.&#xA;Why is that?&lt;/p&gt;&#xA;" OwnerUserId="14561" LastEditorUserId="14561" LastEditDate="2019-08-27T16:12:39.293" LastActivityDate="2019-08-27T16:12:39.293" Title="Why is McMurdo Station in Antartica more hostile than Longyearbyen (Norway), while Longyearbyen is closer to the pole?" Tags="|poles|antarctica|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15787" PostTypeId="2" ParentId="15781" CreationDate="2018-12-17T19:13:12.220" Score="3" Body="&lt;p&gt;It seems your question assumes that Earth magnetic field is caused by natural magnets inside the Earth. Instead, the magnetic field comes from the movement of charged particles.&lt;br&gt;&#xA;Any electrical charged particle in movement generates a magnetic field (see &lt;a href=&quot;https://en.wikipedia.org/wiki/Biot%E2%80%93Savart_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Biot-Savart law&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Amp%C3%A8re%27s_circuital_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ampere law&lt;/a&gt;), hence, thanks to the movement of particles in a liquid mantle we have a magnetic field. Obviously, particles must have electrical charge, which is more common in metals.&lt;br&gt;&#xA;If mantle turns solid, movement is gone, and the magnetic field reduces its strengh.&lt;/p&gt;&#xA;" OwnerUserId="5004" LastActivityDate="2018-12-17T19:13:12.220" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15789" PostTypeId="2" ParentId="15786" CreationDate="2018-12-18T07:49:44.813" Score="5" Body="&lt;p&gt;As to the questions of the flights: McMurdo is about 3.500 km from the next airport (Dunedin in southern New Zealand), while Longyearbyen is only 950 km from Tromsø. It simply is due to the distance and the entailed costs and risks of such a flight.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Antarctica being a continent completely surrounded by water allows for specific climatic conditions. First of all, continental climate near the poles is often harsher than oceanic, since the annual changes in temperature tend to be very high. Antartica in specific gets really cold, due to no sunshine during the winter and the continental climate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly there is no land which hinders the circulation of water and air around Antarctica (&quot;Screaming Sixties&quot;). This circulation effectively cuts off most of air-flow across 60°-latitude from the north, thus preventing warmer air from flowing down south.&lt;/p&gt;&#xA;" OwnerUserId="14194" LastEditorUserId="14561" LastEditDate="2019-05-29T13:38:56.170" LastActivityDate="2019-05-29T13:38:56.170" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15792" PostTypeId="1" AcceptedAnswerId="15802" CreationDate="2018-12-18T12:06:29.677" Score="3" ViewCount="419" Body="&lt;p&gt;I have a general question which may sound naive: archeologists eg in Ancient Greece take a lot of information from preserved pottery they found. What physical attributes of ceramic items made of clay make them so likely to be preserved?&lt;/p&gt;&#xA;" OwnerUserId="13852" LastActivityDate="2018-12-20T04:47:32.267" Title="Preservation of clay items" Tags="|minerals|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15793" PostTypeId="2" ParentId="15770" CreationDate="2018-12-18T20:07:12.957" Score="0" Body="&lt;p&gt;Plan out the trip(s) in detail with the various road cuts stops on the trip guide.  Be sure to do the trip by yourself so that there no surprises (such a 3 feet of snow covering the site or a bridge is washed out). Fossils and arrowheads are a good start.&lt;/p&gt;&#xA;" OwnerUserId="13449" LastActivityDate="2018-12-18T20:07:12.957" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15796" PostTypeId="2" ParentId="15774" CreationDate="2018-12-19T03:23:29.937" Score="1" Body="&lt;p&gt;I would suspect that it's much simpler than actually putting measuring devices in smokestacks, or using satellites.  Just use economic data on fossil fuel production &amp;amp; imports.  If X tons of coal are burned, 3.6X tons of CO2 are produced.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2018-12-19T03:23:29.937" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15797" PostTypeId="2" ParentId="15509" CreationDate="2018-12-19T05:54:59.033" Score="4" Body="&lt;p&gt;Because the surface or top-of-the-atmosphere products are not raw data. Atmospheric corrections have been applied to the raw data and those corrections have been done with a precision that can't be properly captured in 8-bit numbers. You can round data outputs to 8-bits, but there would be information loss.&#xA;Some bands, like atmospheric opacity can be calculated by the model with high precision, and you need a 16-bit number to store such precise values.&#xA;Although the values are stored as 16-bit integers they are floating point numbers, and the scale factor is provided in the same table you mention.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also think that it have to do with having a coherent data format across all the Landsat derived products, including Landsat 8 that have the &lt;a href=&quot;https://en.wikipedia.org/wiki/Operational_Land_Imager&quot; rel=&quot;nofollow noreferrer&quot;&gt;OLI&lt;/a&gt; sensor with a spectral resolution (or bit depth) of 12-bit, that means that the intensity of each pixel is recorded with a number between 0 and 4095, something that provides much more information than the traditional 8-bit (Used by Landsat 7 and before), were intensity is recorded with values between 0 and 255.&#xA;Additional bits give more information and is specially useful to distinguish details in areas with low contrast, like shadows, water or snow fields. For example, all the shades of white in a snow field that corresponded to just one color in Landsat 7, can correspond to 16 different colors in Landsat 8.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Data is distributed in 16-bit files because computers are optimized to deal with 8, 16 or 32 bit numbers, and most software reads images with those bit depths. Therefore, a 12-bit file would not be very compatible, and the smaller standard file that can store all the information of a 12-bit image is a 16-bit data file.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The bands that use 8-bits in the table 6-1 that you mention are quality control bands, that contain information that can be stored in 8 bits without any loss in performance.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-12-19T06:21:36.730" LastActivityDate="2018-12-19T06:21:36.730" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15798" PostTypeId="2" ParentId="15786" CreationDate="2018-12-19T07:18:05.767" Score="6" Body="&lt;p&gt;The lack of oceanic and atmospheric currents going into and around Antarctica from equatorial latitudes means that much less heat is transported from the tropical latitudes to Antarctica compared to Svalbard. Therefore, at equal latitude (i.e. equal solar isolation), temperatures in the south are much colder.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Antarctica, at 75°S latitude most of the land has permanent snow cover.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the flights, in addition to the fact regarding the distances &lt;a href=&quot;https://earthscience.stackexchange.com/a/15789/6298&quot;&gt;mentioned by Erik&lt;/a&gt;, also consider that the only landing strip in McMurdo that can be used by planes with wheels is over an ice shelf (a floating platform of ice). Therefore, installing proper airport instrumentation is impossible, and landing is performed mostly by visual navigation. This is something that can not be done safely in the permanent darkness of winter months or in bad Weather.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are &lt;a href=&quot;https://antarctic-logistics.com/services/air-transport&quot; rel=&quot;noreferrer&quot;&gt;scheduled commercial flights in summer from Punta Arenas to Union Glacier&lt;/a&gt; (latitude 80°S and more hostile than McMurdo). But they are extremely weather dependent. Most flights gets delayed, and waiting a week to fly is not unusual (it was even more common when the landing strip was some kilometers south in &lt;a href=&quot;https://en.wikipedia.org/wiki/Patriot_Hills_Base_Camp&quot; rel=&quot;noreferrer&quot;&gt;Patriot Hills&lt;/a&gt;).&#xA;Therefore, an Ilyushin 76 plane is waiting in Punta Arenas the whole summer just to fly once a week at most. All that added to many other logistical complications makes the round trip ticket to Union Glacier about USD$22,000. It wouldn't be much cheaper to McMurdo, so you can imagine that few people will be able to afford it. Therefore it is kind of a niche business that is not attractive for commercial airlines.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only landing strip that is on solid ground in Antarctica and is large enough to receive commercial planes (medium size, nothing big) is on &lt;a href=&quot;https://en.wikipedia.org/wiki/King_George_Island_(South_Shetland_Islands)&quot; rel=&quot;noreferrer&quot;&gt;King George Island&lt;/a&gt; (latitude 62°S). &lt;a href=&quot;http://dapairline.com/aerovias-dap/&quot; rel=&quot;noreferrer&quot;&gt;DAP airlines&lt;/a&gt; also has scheduled commercial flights there, but they are also extremely expensive.  Tourist flow in winter is minimal; Auroras generally aren't seen there, and  therefore there is little draw for tourists to visit during the winter.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="6298" LastEditDate="2018-12-19T09:29:51.610" LastActivityDate="2018-12-19T09:29:51.610" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15799" PostTypeId="1" CreationDate="2018-12-19T15:09:57.390" Score="3" ViewCount="27" Body="&lt;p&gt;I have known that the atmospheric lifetimes of chemical species were highly dependent on their physicochemical properties. For example, &lt;span class=&quot;math-container&quot;&gt;$SO_2$&lt;/span&gt; might exist for 5-8 days, while &lt;span class=&quot;math-container&quot;&gt;$NO_2$&lt;/span&gt; could only exist less than 1 day. As for the particular contents, the elemental carbon (EC) could undergo longer-range pathway compared to organic carbon (OC) since it was inert and had much less hydroscopicity which forbid the wet deposition. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I studied on the atmospheric trace metals in aerosols, I have hardly found some literatures related with the differences between various trace metals (i.e., polluted elements Pb, Cu, Zn and crustal elements Al, Ca, Ti) in their transportation processes. Is there any key issues controlling the lifetime of trace metal in the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any advices or recommended reading material would be highly appreciated!&lt;/p&gt;&#xA;" OwnerUserId="5214" LastActivityDate="2018-12-19T15:09:57.390" Title="The differences on the atmospheric transportation for various trace metal in atmosphere" Tags="|geology|atmosphere|atmospheric-chemistry|earth-observation|upper-atmosphere|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15800" PostTypeId="1" AcceptedAnswerId="15806" CreationDate="2018-12-20T00:48:20.233" Score="3" ViewCount="418" Body="&lt;p&gt;Comments below &lt;a href=&quot;https://space.stackexchange.com/a/32974/12102&quot;&gt;this answer&lt;/a&gt; to the question &lt;em&gt;Why are lightning towers at launch pads topped with big hollow tubes with spiral windings and not “lightning rod-shaped” lightning rods?&lt;/em&gt; link to a 2013 Kennedy Space Center News item &lt;a href=&quot;https://www.nasa.gov/centers/kennedy/news/releases/2003/release-20030128.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;RELEASE : 13-03 Space Shuttle Weather Launch Commit Criteria and KSC End of Mission Weather Landing Criteria&lt;/a&gt;. It's quite detailed, and discusses cloud transparency in several places. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Are there &quot;transparent&quot; clouds? Are there any standards by which cloud transparency is measured or even visually quantified? I'm wondering if this is a Kennedy Space Center-specific term and they have their own way of estimating cloud transparency, or if it might be a standard meteorological term. Since launches can happen day or night, it calls into question how transparency is determined at night, and if it uses visible light or infrared measurements from ground or satellite.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Here are the most relevant excerpts in case the link breaks at some point in the future. This is from 2003.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is one instance of &quot;transparent cloud&quot;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;The one-minute average of the electric field mill network may not exceed -1 or +1 kilovolt per meter within five nautical miles of the launch pad or the lightning flash at any time within 15 minutes prior to launch. This field mill criteria becomes -1.5 or + 1.5 kilovolts per meter if there are no clouds within 10 nautical miles of the flight path except those which are transparent. Also excepted are clouds with tops below the 41 degrees F. temperature level that have not have been previously associated with a thunderstorm, or associated with convective clouds having tops above the 14 degrees F. temperature level during the last three hours. &lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;as well as a whole section on non-transparent clouds and parts of clouds:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Clouds: (types known to contain hazardous electric fields)&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;[...]&lt;/p&gt;&#xA;  &#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;&lt;p&gt;Do not launch if the flight path is through any non-transparent clouds that extend to altitudes at or above the 32 degrees F. level which are associated with disturbed weather producing moderate or greater precipitation, or melting precipitation, within five nautical miles of the flight path.&lt;/p&gt;&lt;/li&gt;&#xA;  &lt;li&gt;&lt;p&gt;Do not launch through an attached anvil cloud. If lightning occurs in the anvil or the associated main cloud, do not launch within 10 nautical miles for the first 30 minutes after lightning is observed, or within 5 nautical miles from 30 minutes to 3 hours after lightning is observed. &lt;/p&gt;&lt;/li&gt;&#xA;  &lt;li&gt;&lt;p&gt;Do not launch if the flight path will carry the vehicle:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;a) through non-transparent parts of a detached anvil for the first three hours after the anvil detaches from the parent cloud, or the first four hours after the last lightning occurs in the detached anvil.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;b)  10 nautical miles of non-transparent parts of a detached anvil for the first thirty minutes after the time of the last lightning in the parent or anvil cloud before detachment, or the detached anvil after its detachment.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;c) within 5 nautical miles of non-transparent parts of a detached anvil for the first three hours after the time of the last lightning in the parent or anvil cloud before detachment, or the detached anvil after detachment, unless there is a field mill within 5 nautical miles of the detached anvil reading less than 1,000 volts per meter for the last 15 minutes and a maximum radar returns from any part of the detached anvil within 5 nautical miles of the flight path have been less than 10 dBZ on radar (light rain) for 15 minutes. &lt;/p&gt;&lt;/li&gt;&#xA;  &lt;li&gt;&lt;p&gt;Do not launch if the flight path will carry the vehicle through a thunderstorm or cumulonimbus debris cloud which is not transparent and less than three hours old. Launch may not occur within five nautical miles of these debris clouds unless: 1) for 15 minutes preceding launch there is at least one working field mill within five nautical miles of the debris cloud; 2) all electric field mill readings are between -1 kilovolt and + 1 kilovolt per meter within five nautical miles of the flight path; 3) no precipitation has been detected in the debris cloud (less than 10 dbz by radar) within 5 nautical miles of the flight path. &lt;/p&gt;&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2018-12-20T19:25:41.937" Title="Are there &quot;transparent&quot; clouds?" Tags="|meteorology|measurements|clouds|field-measurements|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15801" PostTypeId="2" ParentId="10004" CreationDate="2018-12-20T02:35:56.593" Score="6" Body="&lt;p&gt;&lt;strong&gt;Identification of the phenomenon based solely on the photograph is unfortunately inconclusive, although several reasonable possibilities exist&lt;/strong&gt;. While a wavelike structure is apparent, exact identification of the phenomenon is difficult due to the lack of cloud condensate (which would better illustrate the local vertical air motions ultimately driving cloud development) and of corresponding local weather observations (which could suggest which phenomenon is most likely to occur). Three possibilities seem most likely:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OsOT5.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OsOT5.png&quot; alt=&quot;https://en.wikipedia.org/wiki/Horizontal_convective_rolls&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Horizontal_convective_rolls&quot; rel=&quot;noreferrer&quot;&gt;Horizontal Convective Rolls&lt;/a&gt;&lt;/strong&gt; - a mode of convection in which clouds (and corresponding upward vertical air motion) preferentially organize in approximately linear lines, with downward vertical motion between (image from linked source). These clouds are observed over both land and water surfaces, although formation over water is more likely in cold weather when the water is relatively warm compared to land. This mode is possible, though perhaps least likely, given that weak clouds are visible across the horizontal length of the photograph - well-organized horizontal rolls commonly have clear air between the lines of cloud.  (&lt;a href=&quot;https://en.wikipedia.org/wiki/Horizontal_convective_rolls&quot; rel=&quot;noreferrer&quot;&gt;image source&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QZ1Ch.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QZ1Ch.jpg&quot; alt=&quot;https://www.brockmann-consult.de/CloudStructures/images/gravity-waves-cloud/wave-system.jpg&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;a href=&quot;http://www.theweatherprediction.com/habyhints/64/&quot; rel=&quot;noreferrer&quot;&gt;Gravity wave clouds&lt;/a&gt;&lt;/strong&gt; - clouds that form in the upward motion regions of large-scale &quot;waves&quot; of vertical motion propagating through the atmosphere. Gravity waves are a common phenomenon occurring in many different atmospheric environments, with the resulting clouds varying greatly in appearance depending on the strength of the vertical motion and the amount of atmospheric moisture available for condensation. Given this, gravity wave clouds are a reasonable possibility based on the photograph. (&lt;a href=&quot;https://www.brockmann-consult.de/CloudStructures/images/gravity-waves-cloud/wave-system.jpg&quot; rel=&quot;noreferrer&quot;&gt;image source&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MZJnh.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MZJnh.png&quot; alt=&quot;https://communitycloudatlas.wordpress.com/category/kelvin-helmholtz-waves/&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;a href=&quot;https://communitycloudatlas.wordpress.com/category/kelvin-helmholtz-waves/&quot; rel=&quot;noreferrer&quot;&gt;Kelvin-Helmholtz wave clouds&lt;/a&gt;&lt;/strong&gt; - An overturning motion that may develop at the interface between two atmospheric layers with substantially differing horizontal winds, with cloud condensation (assuming sufficient moisture) taking on an appearance similar to rolling ocean waves (image from linked source). This explanation also seems reasonable, given that air masses with distinct characteristics commonly occur in the lower atmospheric boundary layer and between ocean and land masses. Anecdotally, the clouds in the photograph look most visually similar to near-surface Kelvin-Helmholtz wave clouds I've seen, although again, the lack of actual cloud condensate makes this difficult to assess with any certainty.  (&lt;a href=&quot;https://communitycloudatlas.wordpress.com/category/kelvin-helmholtz-waves/&quot; rel=&quot;noreferrer&quot;&gt;image source&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="14078" LastEditorUserId="14078" LastEditDate="2018-12-20T02:44:07.723" LastActivityDate="2018-12-20T02:44:07.723" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15802" PostTypeId="2" ParentId="15792" CreationDate="2018-12-20T04:47:32.267" Score="4" Body="&lt;p&gt;Its chemically stable oxide, thus non-combustible, does not rot, and fairly hard. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clay ceramics (just ceramic covers a huge swath of materials) are very non-reactive, and fairly hard, both are exactly what you want for preservation. The clay used in these ceramics is what is left when you chemically remove everything else from rock, it is usually the most stable components, mostly oxides. Earthenware clay in particular is often iron rich which makes it even stronger. once refired the clay transforms into a solid mass, essentially a man made rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you look at what destroys artifacts most don't apply or apply the least to clay ceramics. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Rot/decomposition: not an option for clays nothing organics to rot&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Combustion. again not an option for clays, they are already oxides, under the right condition heat can actually make them tougher.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Erosion, this still destroys clay ceramics just like anything else but clay is fairly resistant. It is fairly hard and strong, some stones and metals are more resistant, and these are likewise more likely to be preserved. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Corrosion, clay ceramics ar mostly chemically inert oxides, already in their lowest energy state, so they won't corrode or dissolve when exposed to water, so they survive better than most metallic metals, or ionic compounds. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Theft vs rarity, ceramics generally were not valuable enough to be stolen unlike gold or gemstones or even plain stone, which would survive as well if not better. They were also common enough that that were basically all over a human habitation. If you had a human civilization you usually had hundreds of millions of ceramics. In the case of bricks the homes themselves might be made of it. So they were abundant enough that there was a good chance some would end up in the right conditions to be preserved. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;there is one other feature that applies to clay tablets. When a library full of books burns down the books are destroyed, when a library full of clay tablets burns down they clay actually gets tougher much of the time. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2018-12-20T04:47:32.267" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15803" PostTypeId="2" ParentId="2814" CreationDate="2018-12-20T12:18:59.527" Score="2" Body="&lt;p&gt;The Massachusetts Institute of Technology (MIT) offers a rotating tank setup. This so-called 'weather tank' enables a large set of experiments demonstrating a wide range of phenomena that occur in the atmosphere and ocean. Adding different food dyes into the rotating tank makes it possible to visualize the phenomena, sometimes producing beautifully looking cloud-like structures. I once had the opportunity to show a few experiments to kids, and their responses were overwhelmingly positive. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;http://weathertank.mit.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;their website&lt;/a&gt; for more information and instructions.&lt;/p&gt;&#xA;" OwnerUserId="13524" LastActivityDate="2018-12-20T12:18:59.527" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15805" PostTypeId="1" CreationDate="2018-12-20T12:47:40.530" Score="1" ViewCount="29" Body="&lt;p&gt;I have a series of micro-tomography images of a porous material (received from experimental partners) with a resolution 10 &lt;span class=&quot;math-container&quot;&gt;$\mu m$&lt;/span&gt; with total size 1cm &lt;span class=&quot;math-container&quot;&gt;$\times$&lt;/span&gt; 1cm. Porosity of the porous material lies in the range 7-10&lt;span class=&quot;math-container&quot;&gt;$\%$&lt;/span&gt; and is anisotropic. I am supposed to run fluid dynamical calculations through such porous media.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem I have is that, most probably due to poor resolution of the images, segmented or binary images obtained from the original micro-tomography images differ from each other. The permeability values of the reconstructed porous material is 10-50 times larger than the experimental values. Given that fluid solver is well benchmarked, the only possibility is that reconstructed structure does not corresponds to the original structure. The experimental partners maintain that this is the ideal resolution to include heterogeneity on mm-cm range.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to know if there are algorithms (like multiple points statistics for isotropic media), that can stochastically generate structure and also account for anisotropy. A quick look through Google scholar shows that there are abundant algorithms for isotropic media with porosity higher than 20&lt;span class=&quot;math-container&quot;&gt;$\%$&lt;/span&gt;.&#xA;given that I do not have much experience in this field, any suggestions for algorithms or its impossibility will be highly appreciated.  I am not sure of tags for this question (porous media, anisotropy, reconstruction none of these are available)&lt;/p&gt;&#xA;" OwnerUserId="14579" LastActivityDate="2018-12-20T12:47:40.530" Title="Algorithm for anisotropic porous media reconstruction" Tags="|fluid-dynamics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15806" PostTypeId="2" ParentId="15800" CreationDate="2018-12-20T14:29:57.217" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Are there &quot;transparent&quot; clouds?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes.  One type is called &lt;a href=&quot;https://www.atmos-chem-phys.net/12/12081/2012/acp-12-12081-2012.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;subvisible cirrus clouds&lt;/a&gt;.  They're essentially clouds that are very, very thin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to Reverdy et al. (2012):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Spaceborne lidar observations have recently revealed a previously undetected significant population of Subvisible Cirrus (SVC). We show them to be colder than −74 °, with an optical depth below 0.0015 on average. The formation and persistence over time of this new cloud population could be related to several atmospheric phenomena. In this paper, we investigate if these clouds follow the same formation mechanisms as the general tropical cirrus population (including convection and in-situ ice nucleation), or if specific nucleation sites and trace species play a role in their formation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As for your second question:  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Are there any standards by which cloud transparency is measured or even visually quantified?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;According to Spreitzer et al. (2017), subvisible cirrus may be defined as cirrus with an &lt;a href=&quot;https://en.wikipedia.org/wiki/Optical_depth&quot; rel=&quot;nofollow noreferrer&quot;&gt;optical depth&lt;/a&gt; of less than 0.03.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reverdy, M., Noel, V., Chepfer, H., and Legras, B.: On the origin of subvisible cirrus clouds in the tropical upper troposphere, Atmos. Chem. Phys., 12, 12081-12101, &lt;a href=&quot;https://doi.org/10.5194/acp-12-12081-2012&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.5194/acp-12-12081-2012&lt;/a&gt;, 2012. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Spreitzer, E. J., Marschalik, M. P., and Spichtinger, P.: Subvisible cirrus clouds – a dynamical system approach, Nonlin. Processes Geophys., 24, 307-328, &lt;a href=&quot;https://doi.org/10.5194/npg-24-307-2017&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.5194/npg-24-307-2017&lt;/a&gt;, 2017.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2018-12-20T19:25:41.937" LastActivityDate="2018-12-20T19:25:41.937" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15808" PostTypeId="2" ParentId="15746" CreationDate="2018-12-20T17:03:48.097" Score="1" Body="&lt;p&gt;Reading this question, I'm not sure if you realize what an isotherm is - in this case, imagine peeling rock from the surface of the earth until you reached a temperature of 1300 degrees Celsius. Now, in some areas, such as mid ocean ridges, you wouldn't have to peel back much rock at all, perhaps only a few dozen kilometers. Whereas in regions of old, continental crust, you would have to peel off hundreds of kilometers of rock to get down to rock at 1300 degrees centigrade.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The result would be a lumpy sphere at a constant 1300 degrees, which is your isothermal surface or isotherm. The thickness of the lithosphere is very variable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Interestingly, the Asthenosphere - Mesosphere boundary is created by a mineral phase transition, which is very pressure-dependent; this makes it far more of a smooth sphere.&lt;/p&gt;&#xA;" OwnerUserId="8217" LastActivityDate="2018-12-20T17:03:48.097" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15809" PostTypeId="1" CreationDate="2018-12-21T13:42:45.533" Score="5" ViewCount="126" Body="&lt;p&gt;In the manual of my new dishwasher there is a table of values of water hardness. It goes until 50 dGH (degrees of general hardness) which corresponds to 9,0 mmol/l in the same table.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;https://en.wikipedia.org/wiki/DGH&quot; rel=&quot;noreferrer&quot;&gt;wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;1 dGH is equivalent to 0.17832 mmol per litre of elemental calcium&#xA;  and/or magnesium ions&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The interesting thing is that 6 out of the 10 options for water softener levels are for water hardness greater than 19 dGH and most websites consider 20 dGH as very hard water already.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I couldn't' find any world map or regional map from any place containing dGH values greater than 20. I was wondering whether water hardness levels between 20/30 and 50 are commonplace somewhere in the world.&lt;/p&gt;&#xA;" OwnerUserId="14585" LastActivityDate="2018-12-21T13:42:45.533" Title="Are there places with water hardness between 30 dGH and 50 dGH?" Tags="|water|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15810" PostTypeId="2" ParentId="15720" CreationDate="2018-12-21T22:20:25.733" Score="1" Body="&lt;p&gt;From &lt;a href=&quot;https://digitalcommons.usu.edu/cgi/viewcontent.cgi?article=1263&amp;amp;context=nrei&quot; rel=&quot;nofollow noreferrer&quot;&gt;the link&lt;/a&gt; provided by Keith McClary, the Aral had a salinity of about 1% and a max depth of 69 m. (Could not find average depth in the article.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Caspian Sea, on the other hand, has a salinity of about 1.2%, max depth of 1,025 m, and average depth of 211 m. I think this is enough information to say that the Aral was not just a smaller version of the Caspian, unless your main criteria is salinity.&lt;/p&gt;&#xA;" OwnerUserId="2733" LastActivityDate="2018-12-21T22:20:25.733" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15812" PostTypeId="1" CreationDate="2018-12-22T02:15:38.187" Score="2" ViewCount="4957" Body="&lt;p&gt;Does anyone know how to calculate the vertical integrated moisture flux using NCL in WRF.&#xA;It would be best if you can share a NCL script.&#xA;Here is my code, I used this code to calculate the averaged moisture flux in a month.&#xA;but I am confused the unit of the last output.&#xA;Another question is that I am not sure if I need to divide the output by 9.8?&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;    ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;&#xA;  dir1   = &quot;/Users/gerry/Desktop/WRF_EXTPCP/wrftest/&quot;&#xA;  FILES1 = systemfunc (&quot; ls &quot; + dir1 + &quot;wrfout_d01_* &quot;) &#xA;  a1     = addfiles(FILES1+&quot;.nc&quot;,&quot;r&quot;)&#xA;&#xA;;-------calculate total layer vapor flux--------------------------&#xA;&#xA;  psfc        =   wrf_user_getvar(a1,&quot;PSFC&quot;,-1)*0.01                    ; surface pressure, turn to hPa (; unit of PSFC in WRF is Pa)&#xA;  pres        =   wrf_user_getvar(a1,&quot;pressure&quot;,-1)                     ; air pressure  hPa (time,level,lat,lon)&#xA;  temp        =   wrf_user_getvar(a1,&quot;tk&quot;,-1)                           ; K&#xA;  rh          =   wrf_user_getvar(a1,&quot;rh&quot;,-1)                           ; %&#xA;  ua          =   wrf_user_getvar(a1,&quot;ua&quot;,-1)                           ; m s-1&#xA;  va          =   wrf_user_getvar(a1,&quot;va&quot;,-1)                           ; m s-1&#xA;  ; printVarSummary(psfc)                                                 ; (time,lat,lon)&#xA;  ; printVarSummary(pres)                                                 ; (time,level,lat,lon)&#xA;  ; printVarSummary(temp)                                                 ; (time,level,lat,lon)&#xA;  ; printVarSummary(rh)                                                   ; (time,level,lat,lon)&#xA;  ; printVarSummary(ua)                                                   ; (time,level,lat,lon)&#xA;  ; printVarSummary(va)                                                   ; (time,level,lat,lon)&#xA;&#xA;  psfc1       =   dim_avg_n_Wrap(psfc,0) &#xA;  pres1       =   dim_avg_n_Wrap(pres,0)                               &#xA;  temp1       =   dim_avg_n_Wrap(temp,0)&#xA;  rh1         =   dim_avg_n_Wrap(rh,0)&#xA;  ua1         =   dim_avg_n_Wrap(ua,0)&#xA;  va1         =   dim_avg_n_Wrap(va,0)&#xA;&#xA;                                                    ;https://www.ncl.ucar.edu/Document/Functions/Built-in/mixhum_ptrh.shtml&#xA;  shum        =   mixhum_ptrh(pres1,temp1,rh1,2)    ;units: (hPA,K,%,kg/kg);calculate the specific humidity(2),(1)means mixing ratio&#xA;  printVarSummary(shum)&#xA;  uq          =   ua1 * shum                        ;vapor flux&#xA;  vq          =   va1 * shum&#xA;&#xA;  copy_VarCoords(psfc(0,:,:), psfc1)&#xA;  copy_VarCoords(ua(0,:,:,:), uq)&#xA;  copy_VarCoords(va(0,:,:,:), vq)&#xA;  copy_VarCoords(pres(0,:,:,:), pres1)&#xA;&#xA;;;--vertical integrated moisture flux&#xA;  ptop        =   100                                                                   ; top layer pressure&#xA;  pbot        =   1100&#xA;  uqflux      =   vibeta(pres1(lat|:,lon|:,lev|:),uq(lat|:,lon|:,lev|:),2,psfc1,pbot,ptop)/9.8    ;should divide 9.8??&#xA;  vqflux      =   vibeta(pres1(lat|:,lon|:,lev|:),vq(lat|:,lon|:,lev|:),2,psfc1,pbot,ptop)/9.8&#xA;                                                                                        ; 1 means linear interpolation, 2 means log interpolation&#xA;  qflux       =   sqrt(uqflux^2+vqflux^2)    &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="14589" LastEditorUserId="14589" LastEditDate="2018-12-22T04:15:07.867" LastActivityDate="2019-11-06T10:22:53.560" Title="WRF vertical integrated moisture flux using NCL" Tags="|meteorology|wrf|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="15813" PostTypeId="2" ParentId="15812" CreationDate="2018-12-22T08:14:38.423" Score="5" Body="&lt;p&gt;I am going to explain my answer based on how the authors from this paper calculate this &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0169809506001141&quot; rel=&quot;nofollow noreferrer&quot;&gt;Vertically integrated moisture flux convergence as a predictor of thunderstorms&lt;/a&gt;. This is the equation that is defined in their paper&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ VIMFC = -\frac{1}{g} \int_{700\,hPa}^{1000\,hPa}\ (\frac{\partial u q}{\partial x}+\frac{\partial v q}{\partial y}) * dp $$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a reference for the vertically integrated moisture flux please look at the equation in the reference &lt;a href=&quot;https://iri.columbia.edu/~ousmane/print/Onset/FasuloWebster03_JClim.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;A Hydrological Definition of Indian Monsoon Onset and Withdrawal&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ VIMFT = -\frac{1}{g} \int_{700\,hPa}^{1000\,hPa} (q * u + q * v) * dp$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I will provide an algorithm for a numerical implementation of this equation and opinions can vary what exactly constitutes a &quot;atmospheric layer&quot; in NWP. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this equation q is the specific humidity, u and v are the zonal and meridional velocities, p is the pressure,  g is the acceleration due to gravity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Moisture flux convergence or divergence is &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ (\frac{\partial u q}{\partial x}+\frac{\partial v q}{\partial y})$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Moisture flux is &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ q * u + q * v  $$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You then need to sum the horizontal moisture flux convergence(or in your case moisture flux) over the following layers&#xA;1) 1000 - 925 hPa&#xA;2) 925-850 hPa&#xA;3) 850-700 hPa&#xA;So the definition of what a &quot;layer&quot; is subjective and you can include three pressure surfaces in it if you think a deep layer is required as opposed to a shallow layer. Numerically a layer can be thought as the average values of two pressure surfaces. As an example in your case you take the average of the velocities at the 1000 hPa and 925 hPa surfaces and the average of the specific humidity at the 1000 hPa and 925 hPa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once you calculate the horizontal moisture flux(or if you are calculating MFC then you need to use  finite centered differences and backward and forward differences at the grid boundaries and that procedure is explained in this ESSE answer - &lt;a href=&quot;https://earthscience.stackexchange.com/questions/8418/how-to-calculate-water-vapor-flux-divergence-from-temperature-relative-humidity?rq=1&quot;&gt;Moisture flux convergence numerical procedure&lt;/a&gt; and here &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9634/how-to-compute-du-dx-and-dv-dy-in-moisture-flux-convergence?rq=1&quot;&gt;Finite differences for calculating MFC&lt;/a&gt;) over each layer you multiply that by dp and then sum up the contributions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In response to the questions in the comments &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$&quot;1000 - 925&quot;$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;is not to be interpreted as a subtraction but as an average.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What needs to be done is to take an average of two pressure surfaces in the following manner&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$ q_{layer} = (q_{1000} + q_{925})/2$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$ u_{layer} = (u_{1000} + u_{925})/2$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$ v_{layer} = (v_{1000} + v_{925})/2$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once you do this for every layer multiply by the corresponding value of dp and in this case &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$ dp = 1000 -925 $&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a subtraction. Then you plug the individual values into the sum of individual contributions for each layer and then sum the layers&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$ (q_{layer}* u_{layer} + q_{layer}* v_{layer}) * dp$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The units of VIMFC is typically &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ 10^− 5 \, kg \, m^− 2 \,s^− 1 $$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-02-25T05:56:43.467" LastActivityDate="2019-02-25T05:56:43.467" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15815" PostTypeId="1" CreationDate="2018-12-22T17:53:25.547" Score="3" ViewCount="89" Body="&lt;p&gt;It just occurred to me to ask this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's easy to get a statistical distribution that does not have finite variance. For example, you can sometimes get that when the thing that is measured comes from two random variables, one divided by the other. Sometimes you can't measure a variance. Sometimes you can get a statistical distribution that doesn't even have a mean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When that happens, if you don't notice, you can get a mean and standard distribution from the data. And when you collect more data it will seem to mostly fit. But you get big outliers more often than you'd expect. As you recompute your mean and standard deviation, with more data the standard deviation keeps increasing. Because the longer you keep measuring, the more unexpected events you will have that go outside the predicted range.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Without knowing much at all about floods, they seem to fit this pattern. The news keeps announcing floods that were supposed to be unlikely, unexpected.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, for all I know this is just the news reporting things that should have been expected. Of all the thousands of places we calculate hundred-year-flood levels for, every year we should expect floods that high at one percent of them. Maybe what's happening is really exactly what should be expected.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But it's testable. With enough data you can check whether flooding ought to fit a finite-variance distribution or not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How well has it been tested?&lt;/p&gt;&#xA;" OwnerUserId="12787" LastActivityDate="2018-12-24T02:23:59.773" Title="Is it certain that hundred year floods have finite variance?" Tags="|meteorology|flooding|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15818" PostTypeId="1" CreationDate="2018-12-23T20:17:54.560" Score="2" ViewCount="135" Body="&lt;p&gt;Forests sequester and store substantial amounts of carbon every year, while each year humans emit substantial amounts of carbon into the atmosphere. Is it possible for forests to sequester as much carbon as we're currently emitting each year, and if so is there a rough estimate of how much reforestation would be necessary?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course with such drastic land use changes as it would require to reforest much of the Earth, humanity's carbon emissions would surely change. This is basically a thought experiment, or a rough analysis to highlight the potential (or lack thereof) for trees to sequester our carbon emissions.&lt;/p&gt;&#xA;" OwnerUserId="4789" LastActivityDate="2018-12-23T22:06:18.767" Title="Can reforestation sequester our annual carbon emissions?" Tags="|carbon-cycle|forest|" AnswerCount="1" CommentCount="3" ClosedDate="2018-12-24T15:07:28.750" ContentLicense="CC BY-SA 4.0" />
  <row Id="15819" PostTypeId="2" ParentId="15818" CreationDate="2018-12-23T22:06:18.767" Score="3" Body="&lt;p&gt;Reforestation is a one-off gain in carbon storage. Once a forest is fully mature, the carbon cycles back into the atmosphere as trees die and decay or are burned. So no, this will not sequester all the emissions from fossil-fuel burning. It could help offset it in the short term, but probably mainly just offsets the carbon dioxide from deforestation.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2018-12-23T22:06:18.767" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15821" PostTypeId="2" ParentId="15815" CreationDate="2018-12-24T02:23:59.773" Score="4" Body="&lt;p&gt;I'm sure a statistics guru over on &lt;a href=&quot;https://stats.stackexchange.com/&quot;&gt;cross-validated&lt;/a&gt; could answer this better for you, but here's some general info on estimating flood frequency fyi.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://water.usgs.gov/edu/100yearflood-basic.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;100 year flood&lt;/a&gt; has a 1% probability of occurring in any given year. It is typically estimated by fitting some type of an extreme value distribution to observed flood peaks with additional skew adjustments to account for regional influences or upstream regulation.  In the US, the standard approach is to fit a &lt;a href=&quot;https://en.wikipedia.org/wiki/Pearson_distribution#The_Pearson_type_III_distribution&quot; rel=&quot;nofollow noreferrer&quot;&gt;Log Pearson Type III&lt;/a&gt; distribution to log transformed observed flood peaks.  Until recently, &lt;a href=&quot;https://water.usgs.gov/osw/bulletin17b/dl_flow.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bulletin#17B&lt;/a&gt; was the FEMA approved method for flood risk hydrology when a sufficient record of flood peaks was available.  It was superseded March 2018 by &lt;a href=&quot;https://acwi.gov/hydrology/Frequency/b17c/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bulletin#17C&lt;/a&gt; which has some improved statistical methods.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as your question regarding finite variance, my understanding is that the LP III distribution asymptotically approaches unity and thus remains unbounded without finite variance since from a risk perspective there could always be a larger flood that has not yet been measured.  There are also methods for estimating a Probable Maximum Flood (&lt;a href=&quot;https://www.publications.usace.army.mil/Portals/76/Publications/EngineerRegulations/ER_1110-8-2_FR.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;PMF&lt;/a&gt;) that is meant to represent the most extreme combination of &lt;a href=&quot;https://www.esrl.noaa.gov/psd/arportal/&quot; rel=&quot;nofollow noreferrer&quot;&gt;meteorological&lt;/a&gt; and hydrologic conditions that are reasonably possible in a catchment. &lt;/p&gt;&#xA;" OwnerUserId="14598" LastActivityDate="2018-12-24T02:23:59.773" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15823" PostTypeId="1" CreationDate="2018-12-25T16:25:25.870" Score="4" ViewCount="811" Body="&lt;p&gt;One remarkable thing about the climate history of earth is that despite the fact that solar luminosity was fully 30% lower in the beginning, temperatures were actually quite close to today. Since then temperatures have stayed in a relatively narrow range, allowing life to develop. This lets one conclude that there are dampening mechanisms in the earths climate system.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But predictions for the next few 100 millions of years are unequivocal that the about 10% increase of solar illumination will massively increase temperatures on earth, leading to annihilation of at least all higher life (For details, see for instance here: &lt;a href=&quot;https://en.wikipedia.org/wiki/Future_of_Earth#Solar_evolution&quot; rel=&quot;nofollow noreferrer&quot;&gt;Solar_evolution&lt;/a&gt;, &lt;a href=&quot;https://www.sciencedaily.com/releases/2013/12/131216142310.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;When will Earth lose its oceans?&lt;/a&gt;) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, it stands to reason that at some point the climate dampening mechanisms will be overwhelmed by additional solar irradiation. But there is no indication that the next 10% will be it, if at all the last 500 million years seem to indicate a trend to cooler temperatures: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YHXbs.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YHXbs.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the assumptions that these models are based on to come to their dire predictions? &lt;/p&gt;&#xA;" OwnerUserId="14604" LastEditorUserId="14604" LastEditDate="2018-12-27T12:55:18.610" LastActivityDate="2022-07-21T09:45:32.590" Title="Why is a future increase in solar luminosity by 10% supposed to have disastrous consequences for life on earth when the last 30% did not?" Tags="|climate-change|climate|earth-history|climate-models|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15829" PostTypeId="1" AcceptedAnswerId="15835" CreationDate="2018-12-26T10:14:45.433" Score="3" ViewCount="72" Body="&lt;p&gt;How do we know that there was a flood at a certain place at a certain time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example if there was a flood in place A 200 years ago. How could we detect it?&lt;/p&gt;&#xA;" OwnerUserId="14612" LastEditorUserId="11908" LastEditDate="2018-12-26T23:53:23.713" LastActivityDate="2018-12-26T23:57:44.973" Title="How do we detect floods?" Tags="|geology|sedimentology|hydrogeology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15830" PostTypeId="1" CreationDate="2018-12-26T16:42:12.947" Score="1" ViewCount="626" Body="&lt;p&gt;I know that goldfish can hibernate but I'd like to keep the water warmer for them.  Is moving water colder or warmer than still water?  The water shoots out of &quot;pipes&quot; about 3&quot; above the water's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you for your comments, I have disconnected the water pumps that shoots water into the air.&lt;/p&gt;&#xA;" OwnerUserId="14617" LastEditorUserId="14617" LastEditDate="2018-12-26T21:54:05.747" LastActivityDate="2018-12-27T15:58:26.343" Title="In winter, is pond water warmer with or without a fountain? I have goldfish" Tags="|hydrology|" AnswerCount="2" CommentCount="4" ClosedDate="2018-12-27T17:00:46.823" ContentLicense="CC BY-SA 4.0" />
  <row Id="15833" PostTypeId="2" ParentId="15830" CreationDate="2018-12-26T21:21:04.113" Score="-1" Body="&lt;p&gt;In winter the only use of the fountain is decoration ; as commented it will cool the water. As cold water has a higher oxygen content , there is no need for the aeration value of a fountain or moving water. I am sure what goldfish and koi do in the winter is not hibernation, they just slow down. At 50 F they will eat a little . I have tropicals with the koi so I keep the pond as warm as possible , which turns out to be above 50F for my location.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2018-12-26T21:21:04.113" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15834" PostTypeId="2" ParentId="15823" CreationDate="2018-12-26T21:31:54.603" Score="9" Body="&lt;p&gt;In this regard you can think that the Earth system is like a house with heating but no Air conditioning. Therefore, it has a powerful mechanism to stay warm when the solar illumination is weak (greenhouse effect), but it has no such powerful mechanism to cool down if the solar illumination is too strong.&lt;/p&gt;&#xA;&lt;p&gt;In our analogy, let's say you have used your heating to keep your house nice and warm at 22°C over winter, when outside temperatures were much colder than that. As the temperature outside goes up in the spring, you turn down the power of your heating, so to keep the house at 22°C. Now, a ~10% increase in solar power output would be equivalent to the point were the outside temperature surpasses 22°C. Therefore, even with the heating off, your house temperature will start to rise over 22°C for first time, an you can't do anything about it.&lt;/p&gt;&#xA;&lt;p&gt;The heating mechanism of Earth the greenhouse effect, specially the one due to &lt;span class=&quot;math-container&quot;&gt;${CO}_2$&lt;/span&gt;. But most important, is the thermostat that have kept Earth's temperature in the range of liquid water. This thermostat is based on the fact that an increase of temperature leads to and increase of silicate weathering, that in turn leads to a drop in atmospheric &lt;span class=&quot;math-container&quot;&gt;${CO}_2$&lt;/span&gt; concentrations, and therefore to a drop in temperature. This negative feedback counteracts any warming due to increases in solar irradiation.&lt;/p&gt;&#xA;&lt;p&gt;However, that trick will work only until the point when there is no more &lt;span class=&quot;math-container&quot;&gt;${CO}_2$&lt;/span&gt; in the atmosphere. Then, any increase in solar irradiation will have a direct effect on temperature, and other amplifying feedback will kick in. In particular the greenhouse effect of water vapor: The higher the temperature, the most water vapour in the atmosphere. And water vapor is a very effective greenhouse gas, therefore, that will lead to further increases in temperature.&lt;/p&gt;&#xA;&lt;p&gt;The following figure gives an idea of the different radiative forcings as calculated by the IPCC AR5:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/vUayQ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vUayQ.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, those are relative to the year 1750. The &lt;a href=&quot;https://pubs.giss.nasa.gov/docs/2010/2010_Schmidt_sc05400j.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;total effect of green house gasses is about 155 W/m²&lt;/a&gt;. That corresponds to a 45% of the total energy we receive from the Sun (340 W/m²). That would mean that if you take away all greenhouse gases you can counteract an increase of about 45% of solar power output. In other words, Earth can keep turning the heating down to keep the planet temperature stable as the Sun keeps increasing its power output. However, this calculation is very naive, because we can't remove all greenhouse gases (that would mean removing all the water too). The models you mention are more realistic in this sense and they suggest that the critical points is just a 10% of solar output increase, much closer than the 45% of my ultra-simplistic calculation above.&lt;/p&gt;&#xA;&lt;p&gt;Said that, the references in that Wikipedia article don't seem to use models fully coupled with all the Earth's systems involved (carbon cycle, tectonics, methane, albedo feedback, etc.). Therefore, I would take that 10% value with a lot of caution. However, what is true is that at some point, if you increase solar power enough, the temperature controlling processes of our planet will be overwhelmed, and life on Earth's will face the bigger challenge ever for its subsistence.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="18081" LastEditDate="2022-07-21T09:45:32.590" LastActivityDate="2022-07-21T09:45:32.590" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="15835" PostTypeId="2" ParentId="15829" CreationDate="2018-12-26T21:44:41.130" Score="1" Body="&lt;p&gt;Floods are associated with considerable sediment transport and higher than normal water levels.&#xA;Therefore, the study of sediment layers in river banks, lake bottoms or the ocean floor can reveal large sediment deposition events, that could be associated with floods or landslides. The characteristics of the sediments can be used to identify the process that generated it, and the organic matter trapped within the sediments can be used to date the time of the flood.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is an example of how a sediment layer from a flood looks like in a sediment core&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aQv42.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aQv42.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is taken for a paper that might be interesting to you: &lt;a href=&quot;https://www.researchgate.net/publication/265351096_Lake_Sediments_as_Archives_of_Recurrence_Rates_and_Intensities_of_Past_Flood_Events&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Sediments as Archives of Recurrence Rates and Intensities of Past Flood Events&lt;/a&gt;. The image in the left is a picture of the sediment core (with a overlay showing the changes in reflectance along it).&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2018-12-26T23:57:44.973" LastActivityDate="2018-12-26T23:57:44.973" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15836" PostTypeId="2" ParentId="7690" CreationDate="2018-12-26T22:09:38.350" Score="2" Body="&lt;p&gt;As an addition to the already mentioned effect of the atmosphere for lower solar elevations. As you seem to care about minute differences too. You might want to consider &lt;a href=&quot;https://en.wikipedia.org/wiki/Doppler_effect&quot; rel=&quot;nofollow noreferrer&quot;&gt;Doppler effect&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth-Sun distance during aphelion and perihelion differs by 5,000,000 km. Therefore, the mean radial velocity of Earth with respect to the Sun is 1,141 km/h or 317 m/s. Something that would lead to a frequency change of about 0.0001% on the solar radiation seen from Earth.&#xA;This effect would be nil during aphelion and perihelion, and maximum as we approach perihelion.&#xA;When that would happen in terms of winter/summer will depend on the hemisphere you are at.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This effect might seem negligible, but even much smaller Doppler variations are commonly measured to detect planets around other stars. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a final note, this seasonal effect will be even smaller than the Doppler shifts due to the rotation of the Earth. Such rotation have associated radial speeds up to ~1,666 km/h.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2018-12-26T22:09:38.350" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15839" PostTypeId="2" ParentId="4358" CreationDate="2018-12-27T08:33:10.573" Score="1" Body="&lt;p&gt;I just want to present a visual representation of Fred's very detailed technical answer. In my country right now the Himalayan ranges are in the midst of a cold wave and the Chandra river(tributary of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Chenab_River&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chenab&lt;/a&gt;)has frozen partially in the higher Central Himalayan valley of &lt;a href=&quot;https://en.wikipedia.org/wiki/Lahaul_and_Spiti_district&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lahaul And Spiti&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the river Chandra  and as you can see in the youtube video the surface velocity of the river has reduced considerably and it comes to a almost complete halt towards the end of the video &#xA;    &lt;a href=&quot;https://www.youtube.com/watch?v=3lv3o1GVgyQ&quot; rel=&quot;nofollow noreferrer&quot;&gt;River Chandra partially frozen in Lahaul And Spiti&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastActivityDate="2018-12-27T08:33:10.573" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15840" PostTypeId="2" ParentId="15830" CreationDate="2018-12-27T15:58:26.343" Score="0" Body="&lt;p&gt;In nature, fish survive in ponds due to a lack of turnabout of water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Fresh) Water has its highest density at 4°C, meaning both warmer and colder water float on top of 4°C water. Wind may push surface water to the bottom, slightly lowering the temperature at the bottom of the pond. Still, once the surface starts to freeze, this proccess is discontinued, creating a temperature-gradient with the relatively warm 4°C water at the bottom - until spring. Thus fish don't freeze to death.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Meaning, leaving your fountain running is a rather bad idea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to the issue of possible lack of  oxygen - I can't answer that reliably.&lt;/p&gt;&#xA;" OwnerUserId="14194" LastActivityDate="2018-12-27T15:58:26.343" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15845" PostTypeId="1" CreationDate="2018-12-29T01:08:53.033" Score="1" ViewCount="136" Body="&lt;p&gt;Can coal fires cause earthquakes to happen, or possibly prevent or postpone earthquakes? Also can coal fires trigger(or prevent) volcanic eruptions by affecting flow of magma underground or by some other means?&lt;/p&gt;&#xA;" OwnerUserId="14638" LastActivityDate="2018-12-29T03:51:27.943" Title="Coal fires affecting seismic activity, and also volcanoes" Tags="|volcanology|earthquakes|coal|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15846" PostTypeId="2" ParentId="15845" CreationDate="2018-12-29T03:51:27.943" Score="4" Body="&lt;p&gt;I'm assuming you mean underground fires within coal seams whether they are caused naturally or through human neglect or error.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding the possibility of them &quot;triggering volcanic eruptions by affecting the flow of magma or by some other means&quot;, the answer is no.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Underground &lt;a href=&quot;https://en.wikipedia.org/wiki/Coal_seam_fire&quot; rel=&quot;nofollow noreferrer&quot;&gt;coal seam fires&lt;/a&gt; are mostly smoldering type fires rather than raging fires, due to the lack of oxygen underground. Most are located far away from sources of magma: either laterally or in terms of depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Concerning whether coal seam fires can &quot;cause, ... prevent or postpone earthquakes&quot;, they cannot prevent or postpone earthquakes. Can they cause a &lt;strong&gt;seismic&lt;/strong&gt; earthquake? Unlikely. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Coal seam fires create a void underground. If the fire is extensive and the &lt;strong&gt;extensive&lt;/strong&gt; burnt out zone abuts an active &lt;a href=&quot;https://en.wikipedia.org/wiki/Fault_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;geological fault&lt;/a&gt; the resultant void &lt;strong&gt;may&lt;/strong&gt; cause a ground stress redistribution which might cause a minor earthquake. The other possibility is that the geological strata overlying the burnt out void is weak and eventually subsides, either slowing or quickly. A quick subsidence can create a minor earth tremor and could cause a hole to puncture the surface of the earth, depending on the depth of the coal seam and the void.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2018-12-29T03:51:27.943" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15847" PostTypeId="2" ParentId="15823" CreationDate="2018-12-29T05:49:08.340" Score="4" Body="&lt;p&gt;Any star has a &quot;goldilocks zone&quot; &lt;a href=&quot;https://en.wikipedia.org/wiki/Circumstellar_habitable_zone&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Circumstellar_habitable_zone&lt;/a&gt; where the temperature is suitable for a planet to have Earthlike conditions.  The extent of the zone - the edges where it's not too hot, not too cold, but just right - depends on the star's luminousity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now suppose that 4.5 billion years ago, the primeval Earth orbited somewhere close to the outer edge of the zone.  (Which might be a factor in the &quot;Snowball Earth&quot;?)  As the sun's luminousity increased, the zone moved outwards.  If it continues to increase (as physics says it will), at some point the Earth's orbit will be inside the inner edge of the &quot;just right&quot; zone.  Apparently this is calculated to be 10% over the current luminousity.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2018-12-29T05:49:08.340" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15849" PostTypeId="2" ParentId="8179" CreationDate="2018-12-30T18:33:22.683" Score="1" Body="&lt;p&gt;A rough estimate is the portion of CO2 in the atmosphere (408 ppm) times the mean height (&lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Earth#Pressure_and_thickness&quot; rel=&quot;nofollow noreferrer&quot;&gt;5.6 km&lt;/a&gt;) which gives 2.3 m.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2018-12-30T18:33:22.683" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15850" PostTypeId="2" ParentId="2147" CreationDate="2018-12-31T00:30:09.283" Score="1" Body="&lt;p&gt;All the evidences are that nuclear explosions could have happened in the mantle during the geological time. The best example being the Permian End Extinction. You can read my paper in: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://periodicos.ufsm.br/cienciaenatura/article/view/35821&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://periodicos.ufsm.br/cienciaenatura/article/view/35821&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How is it possible to &quot;calculate&quot; about something that we don't know exactly the composition (earth mantle and other parts of the planet) and to say that it is &quot;impossible&quot;? how many things we have seen in Science that were declared &quot;impossible&quot;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I leave the conclusions to those willing to read and think about the paper. Less math and more facts. In fact each time that I see another fact of the Solar System, it can be explained by this model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If anyboy can find something that can be wrong or not good in the paper, I ask to write directly to my e-mail: sergiometh@gmail.com . I will glad answer the e-mail. In fact I need some crticism, because nobody has shown none hitherto.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Best regards,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Professor Sérgio Meth&lt;/p&gt;&#xA;" OwnerUserId="14650" LastEditorUserId="14650" LastEditDate="2019-01-01T13:39:33.213" LastActivityDate="2019-01-01T13:39:33.213" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15852" PostTypeId="2" ParentId="7627" CreationDate="2018-12-31T01:22:50.223" Score="2" Body="&lt;p&gt;The main factors a plant consider are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Temperature&lt;/strong&gt; (it is important the number of &lt;a href=&quot;https://en.wikipedia.org/wiki/Chilling_requirement&quot; rel=&quot;nofollow noreferrer&quot;&gt;chill hours&lt;/a&gt; the plant receives by year).&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Luminosity&lt;/strong&gt; (related with &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;nofollow noreferrer&quot;&gt;Milhankovic Cycles&lt;/a&gt; and climate of &lt;a href=&quot;https://en.wikipedia.org/wiki/Pleistocene&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pleistocene&lt;/a&gt; in general). &lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Availability of soil and water&lt;/strong&gt; (related with ice covered surface).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The main change between &lt;a href=&quot;https://en.wikipedia.org/wiki/Pleistocene&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pleistocene&lt;/a&gt;'s glaciar/interglaciar for plants is there is new surface to colonize. As ice retreives, ecological succession starts. Non soil lands and permafrost is gradualy replaced by soil, so grass, other plants, and termophyllous trees start to colonize the new environments, while &lt;a href=&quot;https://en.wikipedia.org/wiki/Pinophyta&quot; rel=&quot;nofollow noreferrer&quot;&gt;Coniferous&lt;/a&gt; and other &lt;a href=&quot;https://en.wikipedia.org/wiki/Perennial_plant&quot; rel=&quot;nofollow noreferrer&quot;&gt;Perennial Plants&lt;/a&gt; get restricted. Palinologists find this succession is relatively quick in geological time terms, taking only some decades or centuries (Roucoux, K. H. et al, 2001).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is true for all intereglaciars. Thermophilus taxa as &lt;a href=&quot;https://en.wikipedia.org/wiki/Poaceae&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gramineae&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Artemisia_(genus)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Artemixia&lt;/a&gt;, and grassland in general colonize new &lt;a href=&quot;https://en.wikipedia.org/wiki/Ecological_niche&quot; rel=&quot;nofollow noreferrer&quot;&gt;ecological niches&lt;/a&gt; (Branch, N. P. et al, 2015). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is specialy true at &lt;a href=&quot;https://en.wikipedia.org/wiki/Holocene&quot; rel=&quot;nofollow noreferrer&quot;&gt;Holocene&lt;/a&gt;, where the displacement of cold taxa trees by grassland and other thermophyllous phyllums could became a prelude to Holocene's antrophologic agriculture (Hillman, C., 1996). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pleistocene &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; levels are lower at Pleistocene than at most of Earth's History, as shown in this graph:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ah7Oz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ah7Oz.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Phanerozoic_Carbon_Dioxide.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;. From Gradstein et al.,2005&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;This leads to think plants are adaptated to higger &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; levels than Pleistocene has had and have. This is in fact true, &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; levels are practically the lower known on Earth's History and plants have adaptated theirselves to Earth's environment with higger concentrations. &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Increasing &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; levels at &lt;a href=&quot;https://en.wikipedia.org/wiki/Cannabaceae&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cannabaceae&lt;/a&gt; makes them&#xA;  grow more. Plants are bigger and grow faster with the same amount of&#xA;  ligth and nutrients. &lt;a href=&quot;https://www.leafly.com/news/growing/co2-for-growing-marijuana-plants&quot; rel=&quot;nofollow noreferrer&quot;&gt;Some cultivators use&#xA;  &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; superlevels to make their indoor cultives more&#xA;  efficient&lt;/a&gt;. Photosynthesis become more&#xA;  efficient.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Cannabis_sativa&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cannabis Sativa&lt;/a&gt; endures until 1500 ppm., where &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; become toxic:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qGg5I.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qGg5I.jpg&quot; alt=&quot;Photoshynthesys and CO2 levels for Cannabis Sativa&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: &lt;a href=&quot;http://www.ilovegrowingmarijuana.com/create-best-climate-marijuana-grow-room/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ilovegrowingmarijuana.com&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Both graphs are related. What is shown is thermophyllous plants are adapted non to Pleistocene CO2 levels but for &lt;a href=&quot;https://en.wikipedia.org/wiki/Mesozoic&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mesozoic&lt;/a&gt; / &lt;a href=&quot;https://en.wikipedia.org/wiki/Tertiary&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tertiary&lt;/a&gt; ones. It would be interesting to know the tolerance for perennial plants and common Mesozoic ferns.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;So &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; has increased by human factors, but as&#xA;  temperature has not done it a lot yet and the Earth stays at the same&#xA;  point on Milhankovic Cycles, the only change that happens &lt;em&gt;sensu&#xA;  lacto&lt;/em&gt; because of  &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; emissions on &lt;a href=&quot;https://en.wikipedia.org/wiki/Plant&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kingdom Plantae&lt;/a&gt; is a bit more of efficency on&#xA;  &lt;a href=&quot;https://en.wikipedia.org/wiki/Photosynthesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;photosynthesis&lt;/a&gt; and a bit more of landmass to colonize close to North Pole.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Related link: &lt;a href=&quot;http://www.stratigraphy.org/index.php/ics-chart-timescale&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stratigraphic International Scale&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0033589401922185&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Katherine H.Roucoux, Nicholas J.Shackleton, Lucia de Abreu,  Joachim Schönfeld, Polychronis C.Tzedakis&lt;/strong&gt; (2001). &lt;em&gt;&quot;Combined Marine Proxy and Pollen Analyses Reveal Rapid Iberian Vegetation Response to North Atlantic Millennial-Scale Climate Oscillations&quot;&lt;/em&gt; &lt;strong&gt;Quaternary Research&lt;/strong&gt;&#xA;Volume 56, Issue 1, July 2001, Pages 128-132.&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://riviste.unimc.it/index.php/cap-cult/article/view/1191&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Nicholas P. Branch, Lionello Morandi&lt;/strong&gt; (2015). &quot;&lt;em&gt;Late Würm and Early-Middle Holocene Environmental Change and Human Activities in the Northern Apennines, Italy&lt;/em&gt;&quot;. &lt;strong&gt;Università di Macerata, Dipartimento di Scienze della formazione, dei beni culturali e del turismo&lt;/strong&gt;, Sezione di Beni Culturali, piazzale Bertelli 1, 62100 Macerata, Italia&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://readinglists.ucl.ac.uk/items/3F06BDF2-CCB9-5D36-CC5E-E391248ADA59.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Hillman, C.&lt;/strong&gt; (1996). &lt;em&gt;&quot;The origins and spread of agriculture and pastoralism in Eurasia&quot;&lt;/em&gt;. &lt;strong&gt;UCL Press&lt;/strong&gt;. ISBN-10 1857285379, 1857285387&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.researchgate.net/profile/James_Ogg/publication/46658757_A_New_Geologic_Time_Scale_with_special_reference_to_Precambrian_and_Neogene/links/0f3175381b7a7b97fe000000/A-New-Geologic-Time-Scale-with-special-reference-to-Precambrian-and-Neogene.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Gradstein, FM, JG Ogg and AG Smith&lt;/strong&gt; (2005) &lt;em&gt;&quot;A geologic time scale 2004&quot;&lt;/em&gt;, &lt;strong&gt;Cambridge University Press&lt;/strong&gt; ISBN 0521786738&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-07-17T15:23:50.297" LastActivityDate="2019-07-17T15:23:50.297" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15855" PostTypeId="1" CreationDate="2018-12-31T17:36:43.930" Score="3" ViewCount="26" Body="&lt;p&gt;I am trying to find real time information about flood events in the United States, ideally in polygon format. So far I have found two sources: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;USGS Flood Watch: Points where flood sensors are and the current measurements. This seems comprehensive, but does not contain polygons. &lt;/li&gt;&#xA;&lt;li&gt;NOAA Weather Warnings: Polygons of flood watch areas, but I don't believe this is comprehensive of all parts of the United States. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Are there other polygon datasets in real time? I'd like to know observed flood events. &lt;/p&gt;&#xA;" OwnerUserId="14658" LastActivityDate="2018-12-31T17:36:43.930" Title="Real time flood data in the United States" Tags="|open-data|flooding|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15857" PostTypeId="1" AcceptedAnswerId="15863" CreationDate="2018-12-31T23:42:27.560" Score="4" ViewCount="313" Body="&lt;p&gt;Is it possible that human can built under the poles a controlled system to create again artificial icebergs? In order keep tight the melting ice and reduce the sea level? Can this system impact the quality of life and climate?&lt;/p&gt;&#xA;" OwnerUserId="14662" LastEditorUserId="11908" LastEditDate="2019-01-02T21:26:40.757" LastActivityDate="2019-01-02T21:38:38.587" Title="Is it possible to create ice in poles?" Tags="|geophysics|climate-change|geoengineering|sea-ice|poles|" AnswerCount="1" CommentCount="6" ClosedDate="2019-01-04T01:41:33.717" ContentLicense="CC BY-SA 4.0" />
  <row Id="15862" PostTypeId="1" CreationDate="2019-01-02T10:48:56.743" Score="4" ViewCount="122" Body="&lt;p&gt;I was recently and for the first time caught in an earthquake. This being my first time, I freaked out and had no idea whether the building was going to collapse or not.&#xA;I was later told that this earthquake was nothing to worry about because it was due to the volcanic activity of a nearby volcano (4.9 on the Richter, 1km depth). It caused minor damages near to the volcano, but nothing measurable in our location about 30 km away.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This got me thinking - if volcanic activity is less dangerous than plate activity (because it's closer to the surface, perhaps?), is there some upper limit to the scale of such earthquakes? I suppose that earthquakes and volcanic activity are correlated in some way, but I'm not considering the volcanic activity due to plate movement, rather the &quot;normal&quot; activity of active volcanos.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or rather:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is the largest magnitude measured of an earthquake attributable solely to volcanic activity?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="2559" LastEditorUserId="2559" LastEditDate="2019-01-04T09:12:28.957" LastActivityDate="2019-01-29T16:51:53.020" Title="What is the largest earthquake attributable solely to volcanic activity" Tags="|earthquakes|volcanic-eruption|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15863" PostTypeId="2" ParentId="15857" CreationDate="2019-01-02T17:35:45.933" Score="4" Body="&lt;p&gt;It depends on which pole.&#xA;The south pole is in the middle of Antarctica, with &lt;a href=&quot;https://en.wikipedia.org/wiki/South_Pole&quot; rel=&quot;nofollow noreferrer&quot;&gt;mean temperatures of -57°C&lt;/a&gt;, liquid water doesn't exist there and the air is extremely dry. Therefore, I would say that it is not possible to create more ice due to the lack of liquid water. And if there were any liquid water it would freeze naturally. This will make sense if we have a look at the antarctic geography. This map will help&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BojxT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BojxT.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[image from &lt;a href=&quot;https://geology.com/world/antarctica-satellite-image.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;geology.com]&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One possible action following your line of thought, would be to bring liquid water to the south pole from the coast and let it freeze there. However, the more than 500 km that separates the South pole to the nearest ocean shore (that is actually under hundreds of meters of ice) or 1,300 km to open water, makes this idea very impractical. A similar approach but more efficient would be to pump water from the coast to a nearby antarctic basin, and that would indeed help reducing sea level. This idea have been proposed by scientists. However, to make this effect significant you would need to pump incredible amounts of water, something that makes this geoengineering idea very costly and not very appealing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other scientist have proposed that dumping piles of rock in the ocean floor at specific points could be the most cost-effective way to slowdown sea level rise. The idea is to redirect warm ocean currents away from glaciers, something that could significantly reduce the rate at which they are melting down. This approach would have a much lower (but still very high) cost.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.the-cryosphere.net/12/2955/2018/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This paper&lt;/a&gt; explain this idea and the following figure summarizes it:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/waFBI.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/waFBI.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The North pole in contrast is just in the middle of the Arctic ocean. You could indeed take ocean water there and turn it into icebergs. However, as others have said in the comments, using any kind of cooling system would produce a lot of heat so it would not be a good idea. But you can just enhance the heat transfer with the atmosphere as ski resorts do to make artificial snow. Their approach is to wait for a cold day and spray water into the air. If it is cold enough, the water droplets will turn into ice before falling back to the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, even if you succeed in making icebergs, that would not make any change in sea level, because they are floating. It would be equivalent of melting of ice cubes in a glass, something that doesn't change the level of the liquid in the glass. Here a graphical example of that&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Os6IQ.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Os6IQ.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nevertheless, your feat of engineering would have a positive effect in slowing global warming by covering the ocean with a layer of highly reflective ice. That ice would reflect back to space a lot of sunlight that would have been absorbed by the ocean otherwise. However, when you freeze sea water, most of the salt is expelled, so you would also put a lot of salt into the water, that would make sea water more dense and it would sink. That could have a undesired effect on ocean circulation, so you have to be very careful in studying the side effects of such approach.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similar to the antarctic approach. You might get better results if you pump water from the Arctic ocean and let it freeze on top of a desolate arctic island. However, it still doesn't seem to be the most cost effective approach.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Said that, there is a long list of geoengineering ideas to battle against climate change and sea level rise. However, the most cost-effective way to slowdown sea level rise, is to reduce the rate at which we are consuming stuff. So just buy less and reduce/repair more. Also very important is reducing the use of fossil fuels (something that would also be a side effect of consuming less). Having less children or adopting instead of having your own is also a way to make big contributions to slow down sea level rise.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-01-02T21:38:38.587" LastActivityDate="2019-01-02T21:38:38.587" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15864" PostTypeId="1" AcceptedAnswerId="15867" CreationDate="2019-01-02T18:05:47.880" Score="2" ViewCount="2179" Body="&lt;p&gt;When a landslide occurs, how long does the ordeal typically last? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously the answer is that they vary a lot, however, I'm talking about some specific examples such as the one in &lt;a href=&quot;https://www.npr.org/sections/goatsandsoda/2018/04/08/599526907/life-doesnt-go-on-after-the-mudslides-in-sierra-leone&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sierra Leone&lt;/a&gt; in 2017, or even the landslides in the &lt;a href=&quot;https://www.cnbc.com/2019/01/02/death-toll-from-philippine-landslides-floods-climbs-.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Philippines&lt;/a&gt; going on right now. How quickly did these (or anything similar) landslides move, or how long does it take for them to occur from start to finish?&lt;/p&gt;&#xA;" OwnerUserId="14670" LastEditorUserId="14670" LastEditDate="2019-01-02T23:18:49.033" LastActivityDate="2019-01-03T01:34:48.233" Title="How quickly do landslides occur?" Tags="|natural-disasters|flooding|" AnswerCount="1" CommentCount="2" ClosedDate="2019-01-03T12:57:37.040" ContentLicense="CC BY-SA 4.0" />
  <row Id="15865" PostTypeId="1" AcceptedAnswerId="15866" CreationDate="2019-01-02T21:30:00.947" Score="12" ViewCount="53597" Body="&lt;p&gt;The article entitled &quot;&lt;a href=&quot;https://elpais.com/elpais/2017/06/30/ciencia/1498813164_129942.html&quot; rel=&quot;noreferrer&quot;&gt;54 Celsius degrees in Iran, the highest temperature ever recorded?&lt;/a&gt;&quot; says 56,6 Celsius may be the highest temperature ever recorded, in Death Valley, California, and it also mentions that Iran's heat index peaked at 61,2 Celsius in the event the story was about.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I ask this question because several cities in my province in Argentina are registering heat indexes of over 60 Celsius, with a maximum in the center of Santa Fe city of 65,7° Celsius. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what was the highest temperature ever recorded on the surface of the Earth?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastEditorUserId="11908" LastEditDate="2019-02-03T20:09:33.253" LastActivityDate="2021-11-22T08:00:13.183" Title="What was the highest temperature ever recorded on the surface of Earth?" Tags="|climate|temperature|measurements|extreme-weather|field-measurements|" AnswerCount="3" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="15866" PostTypeId="2" ParentId="15865" CreationDate="2019-01-02T22:50:39.637" Score="19" Body="&lt;p&gt;The record the article is referring about seems to be the same as registered at &lt;a href=&quot;http://www.guinnessworldrecords.com/world-records/highest-recorded-temperature&quot; rel=&quot;noreferrer&quot;&gt;Guiness World Records&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;On 13 September 2012 the World Meteorological Organisation&#xA;  disqualified the record for the highest recorded temperature, exactly&#xA;  90 years after it had been established at El Azizia, Libya, with a&#xA;  measurement of 58°C. The official highest recorded temperature is now&#xA;  &lt;strong&gt;56.7°C&lt;/strong&gt; (134°F), which was measured on 10 July 1913 at Greenland Ranch, Death Valley, California, USA.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Those records are usually well researched, and in this case it matches what is reported by the &lt;a href=&quot;https://public.wmo.int/en&quot; rel=&quot;noreferrer&quot;&gt;WMO&lt;/a&gt;. Since 2007, the WMO Commission for Climatology (CCl) has maintained the &lt;a href=&quot;https://wmo.asu.edu/content/world-meteorological-organization-global-weather-climate-extremes-archive&quot; rel=&quot;noreferrer&quot;&gt;Archive of World Weather and Climate Extremes&lt;/a&gt;. In that archive, the same record is reported as the current highest temperature ever recorded:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jkOX3.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jkOX3.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More details about the record are described &lt;a href=&quot;https://wmo.asu.edu/content/world-highest-temperature&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&#xA;The official WMO press release about the invalidation of the 1922 El Azizia record can be found &lt;a href=&quot;https://public.wmo.int/en/media/news/wmo-ninety-year-old-world-temperature-record-el-azizia-libya-invalid&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is surprising however, that with most the hottest years on record happening in the last few decades, the maximum recorded temperature is still from 1913.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some people have questioned the reliability of those old measurements. More recent and much more reliable measurements seem to top-up at about 54.0°C as pointed out by a &lt;a href=&quot;https://www.wunderground.com/blog/weatherhistorian/hottest-reliably-measured-air-temperatures-on-earth.html&quot; rel=&quot;noreferrer&quot;&gt;very interesting article&lt;/a&gt; brought up by @Plutor in the comments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that you are mixing temperature and &lt;a href=&quot;https://en.wikipedia.org/wiki/Heat_index&quot; rel=&quot;noreferrer&quot;&gt;heat index&lt;/a&gt; in your question. Make sure you understand the difference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS: &quot;Greenland&quot; Ranch... a rather sarcastic name for such a place.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3f9i5.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3f9i5.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Photograph of old Greenland Ranch Station, California, USA (&lt;a href=&quot;https://wmo.asu.edu/content/world-highest-temperature&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="2958" LastEditDate="2019-01-03T12:56:23.413" LastActivityDate="2019-01-03T12:56:23.413" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15867" PostTypeId="2" ParentId="15864" CreationDate="2019-01-03T01:34:48.233" Score="1" Body="&lt;p&gt;A historic yet well observed landslide in the East Kootenays of British Columbia took approximately 100 seconds to settle, &lt;a href=&quot;https://en.wikipedia.org/wiki/Frank_Slide&quot; rel=&quot;nofollow noreferrer&quot;&gt;Frank Slide&lt;/a&gt;.  The slides at Sierra Leone and the Philippines that you mentioned are a different type of slide made of mud and other unconsolidated materials.  I cannot find any information on them but I have witness a few slides in my previous forestry work.  From my observations a slide can occur in 10s of seconds, quick slump flowing fast enough that one cannot escape if you were to be in the path, the one I witnessed took a truck off the road and about 150 meters down a shallow bank the people in the truck escaped but we lost the truck.  They also can occur very slowly, we had an area that due to changes in the drainage up slope started slumping.  The slumping started in March but didn't stop until September.  In the case of the slow slide/slump it took a hectare of forest and slowly moved it down slope and across a road very slowly.  Often the speed of the slide seems to be affected by the amount of water in the soil.  The fastest being the closest to be categorized as a debris flow rather than a slide, the other factor is the steepness of the slope, the steeper falling faster.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2019-01-03T01:34:48.233" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15868" PostTypeId="2" ParentId="15865" CreationDate="2019-01-03T13:50:17.027" Score="6" Body="&lt;p&gt;The &lt;a href=&quot;http://www.geologypage.com/2013/10/hadean-eon.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hadean era&lt;/a&gt; covers the time from the formation of the Earth until 4bn years ago. It was characterized by a surface of molten rock, due to repeated meteor strikes, volcanism and radioactive decay.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;Liquid water oceans existed despite the surface temperature of 230 °C&#xA;(446 °F) because of the atmospheric pressure of the heavy carbon&#xA;dioxide atmosphere.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Origin_of_water_on_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia, &amp;quot;Origin of water&amp;quot;&lt;/a&gt; (*Study from Sleep et al,2001)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Whether this counts as &amp;quot;recorded&amp;quot; is another matter. No-one measured it with a thermometer, but it can be modelled using palaeo-climatology principles.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;N. H. Sleep; K. Zahnle &amp;amp; P. S. Neuhoff.&lt;/strong&gt; &amp;quot;&lt;em&gt;Inaugural Article: Initiation of clement surface conditions on the earliest Earth&amp;quot;&lt;/em&gt; Proceedings of the National Academy of Sciences, &lt;strong&gt;Mar 2001&lt;/strong&gt;, 98 (7) 3666-3672; DOI: 10.1073/pnas.071045698  &lt;a href=&quot;https://www.pnas.org/content/98/7/3666.short&quot; rel=&quot;nofollow noreferrer&quot;&gt;Published in PNAS&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14678" LastEditorUserId="-1" LastEditorDisplayName="user12525" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-01-05T12:13:04.787" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15869" PostTypeId="1" CreationDate="2019-01-03T15:55:54.803" Score="3" ViewCount="83" Body="&lt;p&gt;I have a question regarding the usage of SST values for simulating a real time event such as a tropical cyclone.  I feel that I should use the most updated SST values in order to get the accurate intensity of my storm. But I also think that the updated SST can be cooler than the climatological ones and there are higher chances of convective inhibition within them. This also raises a question on coupled models as they are also used for operational forecasting. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly, since the primitive equations corresponding to a regional weather model comprise an initial value problem I am unable to think of the extent to which the surface boundary conditions can effect the model solutions. &lt;/p&gt;&#xA;" OwnerUserId="11162" LastEditorUserId="11162" LastEditDate="2019-01-03T16:04:30.407" LastActivityDate="2019-01-03T16:04:30.407" Title="Importance of surface boundary conditions in a weather model" Tags="|atmosphere-modelling|tropical-cyclone|" AnswerCount="0" CommentCount="5" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15870" PostTypeId="2" ParentId="10441" CreationDate="2019-01-03T19:04:29.520" Score="2" Body="&lt;p&gt;Photosynthesis is up to about 2% efficient while solar panels are above 20% efficient. So just based on the energy available per unit area of sunlit land or sea, chemical carbon sequestration holds more promise, especially since the area need not be arable. Another advantage of chemical means is that carbon dioxide need not be reduced as far as hydrocarbon, elemental carbon or even carbohydrate for it to be a stable solid. Captured carbon dioxide could be chemically reduced to oxalic acid - a molecule made from two carbon dioxide molecules and just one hydrogen molecule - and stored as a mountain of solid. Since the carbon is almost as oxidized as oxalic acid as it was as carbon dioxide, this minimizes the energy the process requires.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://chemistry.stackexchange.com/a/105022/70787&quot;&gt;Here&lt;/a&gt; I describe how such a project might look. To sequester all the excess carbon dioxide in the atmosphere as a pile of oxalic acid would create a mountain about the size of Mt. Fuji and would require at least one exawatt-hour of electricity.&lt;/p&gt;&#xA;" OwnerUserId="14680" LastEditorUserId="14680" LastEditDate="2019-01-08T00:34:26.807" LastActivityDate="2019-01-08T00:34:26.807" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15871" PostTypeId="1" CreationDate="2019-01-03T22:24:25.153" Score="1" ViewCount="230" Body="&lt;p&gt;I wanna calculate the average moisture flux over a period of time. For example the average moisture flux over an entire summer. I don't have a meteorological background. I have a conceptual confusion about the average moisture flux: &#xA;In case, a site has a moisture flux toward due north with a magnitude of 50 on the first day. It has a moisture flux toward due south with a magnitude of 50 on the second day. Thus, the average moisture flux over these two days is zero? Is it a correct understanding?&#xA;Could you guys give me some useful hints or info?&lt;/p&gt;&#xA;" OwnerUserId="14589" LastActivityDate="2019-01-03T22:24:25.153" Title="how to calculate the average moisture flux over a period of time" Tags="|meteorology|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15873" PostTypeId="1" AcceptedAnswerId="15876" CreationDate="2019-01-04T12:27:23.907" Score="5" ViewCount="135" Body="&lt;p&gt;I am a novice and thus would like you not to mind too much if the answer to my question seems &quot;obvious&quot; to you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I heard that in the cold desert of &lt;a href=&quot;https://en.wikipedia.org/wiki/Ladakh&quot; rel=&quot;noreferrer&quot;&gt;Ladakh&lt;/a&gt;, if you keep your face in sunlight and legs in shade then you can get a frost bite on your legs and a sunstroke on your face. If the sunlight is so much intense at the place (due to excessively thin layer since Ladakh's elevation ranges from 3000 m to 8000 m), then why doesn't snow melt rapidly during the sunshine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One reason that I could think of is the very high albedo of the snow, but is there something else that's preventing the snow from melting very fast out there?&lt;/p&gt;&#xA;" OwnerUserId="14689" LastEditorUserId="6" LastEditDate="2019-01-04T12:31:44.987" LastActivityDate="2019-01-04T20:34:15.113" Title="Why is not snow melting in Ladakh at a rapid pace" Tags="|climatology|snow|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15874" PostTypeId="1" AcceptedAnswerId="15875" CreationDate="2019-01-04T14:32:53.743" Score="1" ViewCount="135" Body="&lt;p&gt;I need data on monthly precipitation for Cape Town between 1970 and 2018. I found this page: &lt;a href=&quot;http://cip.csag.uct.ac.za/webclient2/datasets/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://cip.csag.uct.ac.za/webclient2/datasets/&lt;/a&gt;&#xA;But it only seems to offer information until 2000.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's the same with this: &lt;a href=&quot;http://worldclim.org&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://worldclim.org&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then there is this one: &lt;a href=&quot;https://gis.ncdc.noaa.gov/maps/ncei/cdo/alltimes?layers=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://gis.ncdc.noaa.gov/maps/ncei/cdo/alltimes?layers=0&lt;/a&gt;&#xA;But the data here is very fragmentary. Also the site is currently not working because of the US partial shutdown...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone give me a good hint of where I should look for good data?&lt;/p&gt;&#xA;" OwnerUserId="14690" LastActivityDate="2019-01-24T21:51:50.303" Title="Where can I download recent precipitation data for Cape Town" Tags="|climate-change|climate|open-data|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15875" PostTypeId="2" ParentId="15874" CreationDate="2019-01-04T17:15:46.860" Score="2" Body="&lt;p&gt;It really depends on what you're looking for and what data formats you want to use. If you're looking for single location direct readings from rain gauges, you might have much better luck contacting the &lt;a href=&quot;http://www.weathersa.co.za/&quot; rel=&quot;nofollow noreferrer&quot;&gt;South Africa Weather Service&lt;/a&gt; (though this might not be free and is typically not 'Open' in the strictest sense of the word).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some alternatives to that really depend on what you want (gauges, vs. radar estimates vs. homogenized estimates vs. composite products), the granularity (monthly, daily, hourly; observations or normalized climatologies), the spatial resolution (point locations, grids), and the format (Spreadsheets, GRIB, CF-compliant NetCDF, etc.). &lt;em&gt;It's worth also noting that radar detection of precipitation didn't really become an employed standard until the 1980's (&lt;a href=&quot;https://en.wikipedia.org/wiki/Weather_radar#History&quot; rel=&quot;nofollow noreferrer&quot;&gt;ref&lt;/a&gt;.)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a few options that are open, I would suggest looking over what's available through the NSF's &lt;a href=&quot;https://climatedataguide.ucar.edu&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Center for Atmospheric Research &lt;/a&gt;. The &lt;a href=&quot;https://climatedataguide.ucar.edu/climate-data/cmap-cpc-merged-analysis-precipitation&quot; rel=&quot;nofollow noreferrer&quot;&gt;CMAP: CPC Merged Analysis of Precipitation&lt;/a&gt; or the &lt;a href=&quot;https://climatedataguide.ucar.edu/climate-data/gpcp-monthly-global-precipitation-climatology-project&quot; rel=&quot;nofollow noreferrer&quot;&gt;&#xA;GPCP (Monthly): Global Precipitation Climatology Project&lt;/a&gt; might work for you.&lt;/p&gt;&#xA;" OwnerUserId="5536" LastActivityDate="2019-01-04T17:15:46.860" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15876" PostTypeId="2" ParentId="15873" CreationDate="2019-01-04T20:34:15.113" Score="5" Body="&lt;p&gt;The albedo of the snow would be the primary reason the snow is not melting.  Using a simplified model there are two main sources of heat energy that the snow can absorb, the heat from the ground below, and the heat from the sun and atmosphere above.  The ground and the atmosphere are going to be colder at high elevation because of the lapse rate that gansub mentioned in his comment, which effectively leaves radiant heat from the sun to warm the snow.  Snow is a good reflector of near infrared to UV, the &lt;a href=&quot;https://www.igsoc.org/journal/53/181/j06j041.pdf&quot; rel=&quot;noreferrer&quot;&gt;linked document on the top of page 206&lt;/a&gt; shows the albedo for wavelengths from 400nm (blue/UV) to 900nm (near IR).  On the table you will find that the minimum albedo for snow (assuming fresh snow) is above 0.8 or 80% or better is reflected. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One aspect that might be confusing is that I don't believe you are getting a sunstroke, a body heat issue, but instead a sunburn.  Sunburns are damage to the skin from UV radiation.  At high elevations the UV from the sun is not filtered as much as it is at lower elevations, in addition what does make it through gets reflected back by the snow, effectively doubling the UV exposure when you are in a snow field.  See this site from the &lt;a href=&quot;https://www.who.int/uv/faq/whatisuv/en/index3.html&quot; rel=&quot;noreferrer&quot;&gt;World Health Organization&lt;/a&gt;, &lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2019-01-04T20:34:15.113" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15877" PostTypeId="1" CreationDate="2019-01-05T09:48:11.957" Score="1" ViewCount="135" Body="&lt;p&gt;My understanding is that the earth’s atmosphere was originally formed by the molten earth itself, and the sun was 70% weaker that present. Then as the earth cooled the energy required to keep the atmosphere up against the force of gravity was provided by incoming solar radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Presumably this energy is in excess of that incoming from the sun and outgoing to space. Can anyone tell me how much solar energy is required to kind of keep the sky up. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So say we started with the present sun and current atmospheric mass with the earth at its blackbody temperature with the current solar energy hitting its surface - 255K. How much additional solar energy is required to lift those gasses not already off the ground at this temperature up into the sky?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I realise that the current energy reaching the earth’s surface is due to the atmosphere absorbing some of the energy but I’m interested in the excess energy in the earth/atmosphere system required to keep the atmosphere up.&lt;/p&gt;&#xA;" OwnerUserId="14695" LastActivityDate="2019-01-05T17:43:31.153" Title="How much energy is required to hold the earth’s atmosphere up against the forces of gravity?" Tags="|atmosphere|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15878" PostTypeId="2" ParentId="15877" CreationDate="2019-01-05T17:43:31.153" Score="2" Body="&lt;p&gt;I can not comment on whether your understanding about the formation of the atmosphere (your first paragraph) is correct. However, given that the complete atmosphere lied at the surface at some point, it is possible to calculate the amount of energy to lift this towards its current state. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The calculations will be done for a small surface area of one meter squared and choosing values corresponding roughly to the global averages. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;First we calculate the gravitational potential energy of the atmospheric column as follows &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ E_{atmos} = m_{atmos} \cdot g \cdot h_{atmos}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;with &lt;span class=&quot;math-container&quot;&gt;$h_{atmos}$&lt;/span&gt; the height of the center of mass of the atmospheric column. Surface atmospheric pressure (&lt;span class=&quot;math-container&quot;&gt;$P_{surface}$&lt;/span&gt;) is the force resulting from the mass of the atmospheric column under gravitational acceleration. Therefore, the above can be rewritten as &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ E_{atmos} = P_{surface} \cdot h_{atmos}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The centre of mass at the atmosphere is approximately at &lt;span class=&quot;math-container&quot;&gt;$h_{atmos}$&lt;/span&gt; = 5 km (one can look at maps of the 500 hPa geopotential heights for example). For surface pressure we can take the standard atmosphere (101325 Pa). Plugging in the numbers: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ E_{atmos} = 101325\,Pa \cdot 5000\,m = 5.1e8\,N m^{-1} = 5.1e8\,J\,m{-2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get to the total energy, this number needs to be multiplied by the surface area of the earth. However, it is more insightful to get a certain timescale out of this value. We can calculate how long it would take for the sun to deliver this energy to the earth's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ \tau_{sun} = \frac{E_{atmos}}{SI_{avg}}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With &lt;span class=&quot;math-container&quot;&gt;$SI_{avg}$&lt;/span&gt; the global average incoming solar radiation (not taking into account atmospheric absorption). Plugging in the values&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ \tau_{sun} = \frac{5.1e8\,J\,m{-2}}{340\,W\,m{-2}} = 1.5e6 s = 17.5 days$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So it would take about 17-18 days for the sun in order to 'lift up' the atmosphere from the surface to its current height.&lt;/p&gt;&#xA;" OwnerUserId="13524" LastActivityDate="2019-01-05T17:43:31.153" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15881" PostTypeId="1" CreationDate="2019-01-06T06:59:51.180" Score="1" ViewCount="67" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The Indian Resource Panel shall prepare a strategic roadmap for &lt;strong&gt;utilisation of secondary resources for meeting the developmental needs.&lt;/strong&gt; India is the first country to constitute a National Resource Panel. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;An extract from a book am reading on Environment whose author is not internationally known but I’ll still mention his name, Shankar. &#xA;The author has it mentioned as a Do You Know. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I ran a google search but couldn’t find any explanation to it. &lt;/p&gt;&#xA;" OwnerUserId="14699" LastEditorUserId="14699" LastEditDate="2019-01-06T07:17:37.310" LastActivityDate="2019-01-06T10:31:06.280" Title="What are secondary resources?" Tags="|environmental-protection|resources|" AnswerCount="1" CommentCount="6" ClosedDate="2019-01-06T14:54:53.587" ContentLicense="CC BY-SA 4.0" />
  <row Id="15882" PostTypeId="2" ParentId="15881" CreationDate="2019-01-06T10:25:40.357" Score="1" Body="&lt;p&gt;lets say a water company do deliver water to a city but as the city expands the water source are no longer able to keep up with the demand so the water company have to drill a new well,This is now an alternative source for water the company will still use the primary source for water but will need to use the secondary source in periods of high water demand.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same is true for building materials if the primary supplier are not able to deliver what you need,You have to get it from an alternative source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And as i mention in my comment,my primary supplier of electric power is hydro power,So this is the primary source of power for me and if i use more power than they can produce the rest must be supplied from an alternative source,Here this will be wind power or import from other sources.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In denmark the primary source for electric power is wind and the secondary sources is hydro power from norway or coal power from the continental europe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;the comment from fred is an answer to this question too&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6258" LastEditDate="2019-01-06T10:31:06.280" LastActivityDate="2019-01-06T10:31:06.280" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15883" PostTypeId="1" CreationDate="2019-01-06T15:57:48.233" Score="2" ViewCount="919" Body="&lt;p&gt;How to calculate wind direction from uwind and vwind?&lt;br&gt;&#xA; if uwind and vwind are -1.82 , -3.18 respectively&lt;/p&gt;&#xA;" OwnerUserId="14600" LastActivityDate="2019-01-06T16:22:59.057" Title="How to calculate Wind direction from uwind and vwind?" Tags="|meteorology|oceanography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15884" PostTypeId="2" ParentId="15883" CreationDate="2019-01-06T16:14:30.207" Score="5" Body="&lt;p&gt;The base formula for the direction &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\theta=atan2\left(\frac{\text{uwind}}{\text{vwind}}\right)$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where &lt;span class=&quot;math-container&quot;&gt;$atan2$&lt;/span&gt; is the four quadrant inverse tangent. Note that if you used the normal inverse tangent your results will be all collapsed to the first quadrant (0° to 90°). Also note that depending on the platform the result can be in radians or degrees (most often in radians, some platforms have a function atan2d that return values in degrees).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you get a negative value (which is the same direction but measured counterclockwise), you have to add 360° (or &lt;span class=&quot;math-container&quot;&gt;$2\pi$&lt;/span&gt; radians).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This will give you the direction the wind is coming from. For the direction is going to, you have to add/substract 180° (or &lt;span class=&quot;math-container&quot;&gt;$\pi$&lt;/span&gt; radians).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the values you provide, the answer would be 210°.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-01-06T16:22:59.057" LastActivityDate="2019-01-06T16:22:59.057" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15885" PostTypeId="1" CreationDate="2019-01-06T16:59:10.680" Score="5" ViewCount="185" Body="&lt;p&gt;Do sound waves from volcanic eruptions travel around the world? I recently read about the Krakatoa eruption and how sound waves from that eruption traveled around the globe 4 times and were detected by weather stations through pressure spikes in barometers (&lt;a href=&quot;http://nautil.us/blog/the-sound-so-loud-that-it-circled-the-earth-four-times&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Sound So Loud That It Circled the Earth Four Times&lt;/a&gt;). What I'm curious about is whether this has ever been documented in other volcanic eruptions?&lt;/p&gt;&#xA;" OwnerUserId="14702" LastEditorUserId="18088" LastEditDate="2022-05-28T22:33:53.747" LastActivityDate="2022-05-28T22:33:53.747" Title="Do sound waves from volcanic eruptions travel around the world?" Tags="|volcanology|waves|barometric-pressure|air|" AnswerCount="1" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15886" PostTypeId="1" AcceptedAnswerId="15887" CreationDate="2019-01-06T01:17:48.827" Score="2" ViewCount="1783" Body="&lt;p&gt;I was trying to find the amount of energy created during a volcanic explosion, I have been looking around, There was one formula I found where I could use the Kinetic Energy,  which is &lt;span class=&quot;math-container&quot;&gt;$KE=\frac{1}{2}mv^2$&lt;/span&gt;, but I feel that there is something more.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am looking at Volcanic Explosivity Index for Krakatoa, which says that it is class 6, and it has a TNT equivalence to 200 megatons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was hoping if someone can give me the correct calculation to find the means of measuring a volcanic explosion in joules, tonnes or higher.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or if there are other means or formula like finding the result in newtons, go ahead with that as well&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Volcanic_Explosivity_Index&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Volcanic_Explosivity_Index&lt;/a&gt;&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/1883_eruption_of_Krakatoa&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/1883_eruption_of_Krakatoa&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is information about the Volcanic Explosivity Index&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://geology.com/stories/13/volcanic-explosivity-index/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://geology.com/stories/13/volcanic-explosivity-index/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It says you can measure it by volume of volcanic material, height of eruption column and duration of explosion.&lt;/p&gt;&#xA;" OwnerUserId="14696" OwnerDisplayName="C. Jordan" LastEditorUserId="20" LastEditDate="2019-01-07T06:33:07.450" LastActivityDate="2019-01-07T06:33:07.450" Title="Volcanic Eruption Calculation?" Tags="|geophysics|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15887" PostTypeId="2" ParentId="15886" CreationDate="2019-01-06T18:43:00.050" Score="3" Body="&lt;p&gt;There are apparently several ways of estimating total energy release in volcanic eruptions, all of them approximate. Energy is released as heat, vibrations, deformation of rock, kinetic energy of ejected material etc. Calculating an exact energy budget is hard.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Volcanic_Explosivity_Index&quot; rel=&quot;nofollow noreferrer&quot;&gt;The  Volcanic Explosivity Index (VEI)&lt;/a&gt; indicates how much volume the ejecta of the eruption takes up. &lt;a href=&quot;https://www.iugg-georisk.org/presentations/pdf/SDLCR_volcanos_Mexico.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;One can estimate the energy release as a function of VEI class&lt;/a&gt; &lt;span class=&quot;math-container&quot;&gt;$M$&lt;/span&gt; as &lt;span class=&quot;math-container&quot;&gt;$E=10^{aM+c}$&lt;/span&gt; Joule where &lt;span class=&quot;math-container&quot;&gt;$a\approx 0.79$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$c = 14$&lt;/span&gt; (based on &lt;a href=&quot;https://link.springer.com/article/10.1007/BF00278206&quot; rel=&quot;nofollow noreferrer&quot;&gt;de La Cruz-Reyna 1991&lt;/a&gt;). That was in turn based on estimates from Yokoyama (1957).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://academic.oup.com/gji/article/167/1/467/2085883&quot; rel=&quot;nofollow noreferrer&quot;&gt;Another way of estimating is to look at seismic signals and calculate how much energy the eruption must have had to produce the measured waveforms&lt;/a&gt;. Seismologists have fairly decent models of the scaling of energy with shaking intensity, and one can estimate how much it attenuates with distance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.frontiersin.org/articles/10.3389/feart.2014.00010/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;A third way is to consider how much the pressure in the magma chamber is reduced times the reduction in volume&lt;/a&gt;, &lt;span class=&quot;math-container&quot;&gt;$E=\Delta P\cdot V$&lt;/span&gt;. A pressure drop of 5 MPa is apparently typical, and the volume reduction is proportional to the ejected volume (with some scaling factor from packed rock to ejecta).&lt;/p&gt;&#xA;" OwnerUserId="12421" OwnerDisplayName="Anders Sandberg" LastActivityDate="2019-01-06T18:43:00.050" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15890" PostTypeId="1" AcceptedAnswerId="16132" CreationDate="2019-01-07T14:06:33.457" Score="1" ViewCount="179" Body="&lt;p&gt;I live in Florida (&lt;a href=&quot;https://www.cnn.com/2013/03/01/us/florida-sinkhole/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;aka the land of sink holes&lt;/a&gt;).  Due to the flat nature of my area, it is common place for housing developments (and any developments really) to dig large drainage areas to give water a place to go other than the newly constructed buildings.  In the case of my neighborhood that means that a large depression was dug to drain water from the land where all the surrounding houses were built.  The drainage area is roughly square, probably 50 meters by 50 meters in size, and about 4-5 feet deep (I'm pretty sure this is a common practice, even in less-flat areas).  In our case houses are built surrounding it in a big &quot;block&quot;, and my house backs up to it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's covered in grass and well maintained, so I take my kids back there to run around semi-regularly.  We bought our house about 6 months ago, and about 3 months ago a large sink hole opened up in this drainage area.  Large in this case means that it is probably 2 meters deep at the deepest point and has an overall diameter of about 5 meters.  It's on the other side of the drainage area so it isn't right next to my house, but it's certainly not far.  We also recently found a second (and much smaller) hole - approximately 20 centimeters in diameter and 20 centimeters deep.  This small one is much closer to my back yard.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course I'm definitely interested in this sink hole as it pertains to my house (aka does this imply that this area may be prone to sink holes), but I'm also curious about these things generally.  To keep it to a simple question, I'm wondering if this is a sink hole that opened up like all other sink holes in Florida - aka a collapsed underground hole/cave that just &lt;em&gt;happened&lt;/em&gt; to miss all the surrounding houses?  Or is it possible that this is a local affect, aka something about these drainage areas can lead to sink hole formation, implying no immediate concern to the surrounding houses?  I realize this is probably not an answerable question for my specific sink hole, but I thought people here might have some insight into whether or not drainage areas might cause their own sink holes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In case it isn't clear, this drainage area has no drain point itself.  During heavy rain, water flows into the drainage area and then slowly evaporates or percolates into the ground.  In case it matters, when it does rain, water typically collects on the opposite side of the drainage area than the side which contains the sink hole. I.e. the sinkhole is on the &quot;high&quot; side of the drainage area (although the elevation difference probably isn't more than a dozen centimeters).&lt;/p&gt;&#xA;" OwnerUserId="14511" LastEditorUserId="14511" LastEditDate="2019-01-07T15:32:03.577" LastActivityDate="2019-02-01T18:43:34.153" Title="Sink holes in drainage area" Tags="|geology|geography|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15892" PostTypeId="1" CreationDate="2019-01-07T16:39:10.470" Score="1" ViewCount="55" Body="&lt;p&gt;I was wondering if anybody had any insight or thoughts on a technological bottleneck we are facing in data collection. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically, we have vessels (single operator) dig the substrate for collection purposes in water depths generally shallower then 35' (maximum of 35' but average about 15') via bullrake (large clam rake with a telescopic handle). The digger stands aboard a vessel with the rake and is drifting along by current/wind, thus completing a &quot;transect&quot; after a period of time based on how quickly the vessel is drifting. Transects typically range from 5-50m in length. Currently we are measuring the length of the transect (which is define as the point at which the rake first begins digging along the bottom until the point digging ceases on the bottom) via GPS fixes at the start and end of each transect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At it's best, this induces inherent inaccuracy in transect length relying on GPS (although GPS accuracy is at least recorded at each fix). I was wondering if anybody here could think of a solution to record transect length more reliably or a workaround to equate transect length more accurately? Is there a piece of equipment which could be affixed to the rake to measure its distance traveled?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Proper solutions must be able to be operated by a single person while aboard a vessel and be straightforward and quick enough to rival (preferably beat out right) the time it takes to allow for a proper GPS fix and manual recording of coordinates. &lt;/p&gt;&#xA;" OwnerUserId="14716" LastEditorUserId="11908" LastEditDate="2019-01-07T17:41:25.807" LastActivityDate="2019-01-07T17:41:25.807" Title="Measuring Transect Length on Sea Floor" Tags="|oceanography|sea-floor|research|gnss|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15893" PostTypeId="2" ParentId="15892" CreationDate="2019-01-07T17:34:27.817" Score="1" Body="&lt;p&gt;The easiest and larger improvement in accuracy you can implement is switching from the non-differential single frequency GPS measurement to a double frequency and/or differential GPS measurements. That usually takes down the error of single measurements from a few meters to a few tens of centimetres or less.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The GPS systems that are within cell phones, tablets and most ships calculate their position standalone and in real-time using only one of the two civilean frequencies that the GPS satellites broadcast. The greatest source of error of those measurements are the discrepancy between the atmospheric and ionospheric models and the reality.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two workarounds to this problem, both often used simultaneously to get even better results.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first workaround, is two use more sophisticated GPS instruments that can record the two civilian frequencies that the GPS satellites transmit. As each frequency is refracted by the atmosphere in a different way, the GPS can better calculate its effect and correct for it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second workaround is to do differential measurements. That is correcting the measurements of your GPS based in the errors recorded at the same time by a nearby GPS station at a fix known position. That is call a base station.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can install your own base station on the ground near the area you work, or use one from the international network of base stations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My recommendation, would be that you buy a double frequency GPS. If cost is a constrain, go for an used one on e-bay and you can get an excellent quality GPS for just a few hundred dollars. Then you put that GPS to record while you do your transect and it will generate a file with raw GPS measurements. Then, later, at home you upload that file (maybe after a format conversion) to a free GPS processing service and you will get back a file with the GPS track with MUCH better accuracy than your handheld GPS.&#xA;This would be equivalent to use the first workaround I described and the processing I'm suggesting here is called PPP (Precise Point Positioning).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you record the raw GPS data and do the processing later is called post-processing, and it is the best practice if you don't need the high accuracy measurements in real-time. After a week or so, the DoD issues high accuracy corrections of the positions of the satellites and their internal clocks. So if you wait for this high accuracy corrections you can get better precision than any real-time processing. All this is already embedded in those free online processing systems. So you just need to wait a week, upload your file and wait for the result.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The next step would be to have a second GPS and set up your own base station (or check if you work reasonably close to an existing base station). However, my guess is that the gain in accuracy won't make much sense given the errors in the relative position between your GPS and your bullrake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A second different approach would be to equip your bullrake with some sort of distance measuring wheel, that rolls over the sea floor and records the distance traveled by the bullrake. But it might be significant technical challenges to make such a device work reliably.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-01-07T17:34:27.817" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15894" PostTypeId="5" CreationDate="2019-01-07T17:43:16.567" Score="0" Body="" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-01-07T17:43:16.567" LastActivityDate="2019-01-07T17:43:16.567" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15895" PostTypeId="4" CreationDate="2019-01-07T17:43:16.567" Score="0" Body="Global Navigation Satellite System, including GPS, GLONASS, Galileo and BeiDou" OwnerUserId="11908" LastEditorUserId="6031" LastEditDate="2019-04-05T04:04:53.300" LastActivityDate="2019-04-05T04:04:53.300" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15899" PostTypeId="5" CreationDate="2019-01-08T06:40:08.813" Score="0" Body="" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-01-08T06:40:08.813" LastActivityDate="2019-01-08T06:40:08.813" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15900" PostTypeId="4" CreationDate="2019-01-08T06:40:08.813" Score="0" Body="Global Position System" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-01-08T06:40:08.813" LastActivityDate="2019-01-08T06:40:08.813" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15901" PostTypeId="1" AcceptedAnswerId="15902" CreationDate="2019-01-08T10:33:28.100" Score="13" ViewCount="3502" Body="&lt;p&gt;The Dead Sea, rivers in California and the Aral Sea  are said to be shrinking due to water usage, e.g. for agriculture. Yet the water must go &lt;em&gt;somewhere&lt;/em&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;After the fields are irrigated,  the water either soaks into the ground or evaporates. In the first case, the groundwater is replenished. In the second case, the water ends up as rain, presumably within a few hundred kilometers  of the evaporation point. Either way, the water  gets back in circulation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what is happening here? How can water be &quot;used up&quot;?&lt;/p&gt;&#xA;" OwnerUserId="14723" LastEditorUserId="14723" LastEditDate="2019-01-08T12:28:40.920" LastActivityDate="2019-01-08T16:29:25.353" Title="How is it possible to use up the water in a region?" Tags="|meteorology|hydrology|water|groundwater|" AnswerCount="3" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="15902" PostTypeId="2" ParentId="15901" CreationDate="2019-01-08T11:42:02.440" Score="14" Body="&lt;p&gt;You're making a mistake, at least for the second case:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In the second case, the water ends up as rain, presumably within a few hundred kilometers of the evaporation point.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You cannot model a dry region (or indeed any region on earth) as a closed system for hydrological purposes.  When water evaporates in a dry climate, it transports much farther than a few hundred kilometres.  General circulation can transport airmasses for thousands of kilometres.  In all likelihood, when the water finally precipitates it will do so in a different catchment area and/or far upstream, often in an area that already has plenty of precipitation.  From there it may flow thousands of kms to different climate areas yet.  This is why in particular hydro lakes in hot climates have such a large impact on ecology: a hydro lake is far larger evaporation than a river, due to its much larger surface area and other factors.  When water from a dry region is gone, it can, for all practical purposes, be counted as a loss.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2019-01-08T12:44:25.087" LastActivityDate="2019-01-08T12:44:25.087" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15903" PostTypeId="2" ParentId="15901" CreationDate="2019-01-08T12:53:50.483" Score="16" Body="&lt;p&gt;This is a really complex problem and would require a really detailed explanation about atmospheric circulation, meteorology and hydrology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The short answer to your question is that water is going somewhere else. If you look at the studies about moisture recycling, among the others &lt;a href=&quot;https://www.earth-syst-dynam.net/5/471/2014/esd-5-471-2014.pdf&quot; rel=&quot;noreferrer&quot;&gt;van der Ent et al 2014&lt;/a&gt; or &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2010WR009127&quot; rel=&quot;noreferrer&quot;&gt;2010&lt;/a&gt;, you can see that the precipitation that generates from locally generated moisture is just a minor fraction, and usually is higher in very wet areas. So, your assumption of the &quot;&lt;em&gt;few hundreds kilometers&lt;/em&gt;&quot; is generally wrong. Considering a very wet area like the Amazon forest, you can see that the moisture locally generated is the major source (about 70% in quantity) of the precipitations in South-Eastern Brazil. This is due to the atmospheric circulation and the topography of the continent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/h6otz.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/h6otz.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2010WR009127&quot; rel=&quot;noreferrer&quot;&gt;van der Ent et al 2010&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To fully answer your question, both in case of precipitation and in the case of underground percolation, the water used locally in agriculture or other uses, would go to contribute to other drainage basins (both in the cases of surface water and underground aquifers).&lt;/p&gt;&#xA;" OwnerUserId="8087" LastActivityDate="2019-01-08T12:53:50.483" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15905" PostTypeId="2" ParentId="15901" CreationDate="2019-01-08T16:29:25.353" Score="2" Body="&lt;p&gt;Most of the world's land is more than one hundred kilometers from the nearest ocean, yet still gets rain. There are portions of the Rockies that are about a thousand kilometers from the nearest ocean. And since clearly a large portion of the precipitation that lands in the Rockies flows to the ocean, there must be some mechanism taking water back to the Rockies from the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, &quot;several hundred kilometers&quot; is a rather large distance. The Dead Sea is only about 50 km long and 15 km wide with an area of 605 km^2; if you draw a circle of radius 100 km, the Dead Sea would make up about 2% of that region. 100 km from the Dead Sea gets you to the Mediterranean, and 200 km gets you to Egypt, Saudi Arabia, Syria, or Lebanon. So even if water were to stay within a few hundred kilometers, it would be unlikely to make its way back to the Dead Sea.&lt;/p&gt;&#xA;" OwnerUserId="11501" LastActivityDate="2019-01-08T16:29:25.353" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15907" PostTypeId="1" AcceptedAnswerId="15925" CreationDate="2019-01-08T20:36:02.003" Score="0" ViewCount="170" Body="&lt;p&gt;According to this article &lt;a href=&quot;https://futurism.com/drops-of-jupiter&quot; rel=&quot;nofollow noreferrer&quot;&gt;Drops of Jupiter&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Raising 39 trillion kilograms of water 175 meters above sea level will&#xA;  increase the Earth’s moment of inertia, and thus slow its rotation.&#xA;  However, the impact will be extremely small. NASA scientists&#xA;  calculated the shift of such a mass will increase the length of day by&#xA;  only 0.06 microseconds&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;is it possible to know which equations NASA used or is it too complicated to calculate that for regular people ? (thus it would be NASA required to do the math)&lt;/p&gt;&#xA;" OwnerUserId="9635" LastActivityDate="2019-01-14T09:23:44.513" Title="Which are the equations needed to calculate how much moving Earth's water with dams would change Earth's rotation speed?" Tags="|earth-rotation|" AnswerCount="1" CommentCount="1" ClosedDate="2019-01-12T19:17:50.840" ContentLicense="CC BY-SA 4.0" />
  <row Id="15908" PostTypeId="1" CreationDate="2019-01-09T01:34:18.147" Score="3" ViewCount="31" Body="&lt;p&gt;I have wind data from a Met station (Speed and Direction), and I'm looking for a way to characterize a strong coherent wind. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;AKA - Wind that averages 12 m/s out of the East for 2 days would have a different (higher) value than a 12 m/s wind that comes from multiple directions for 2 days. Is there an accepted method for this? If so, how is it calculated? &lt;/p&gt;&#xA;" OwnerUserId="14733" LastActivityDate="2019-01-09T01:34:18.147" Title="What is the accepted measure for Wind Coherency (Strength and Direction)" Tags="|meteorology|wind|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15909" PostTypeId="1" AcceptedAnswerId="15915" CreationDate="2019-01-09T10:43:20.733" Score="1" ViewCount="1245" Body="&lt;p&gt;Is there a location, in the southern hemisphere, where I could pitch a tent that I would be able to see the sun at any time of day for, say, more than a week?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How far north could I go and still be able to see the sun for two days or more?&lt;/p&gt;&#xA;" OwnerUserId="14736" LastActivityDate="2019-01-11T16:54:13.107" Title="Southern Hemisphere: What is the most Northern latitude where the sun can be seen for more than 24 hours?" Tags="|sun|poles|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15912" PostTypeId="1" AcceptedAnswerId="15914" CreationDate="2019-01-09T12:37:37.017" Score="1" ViewCount="3116" Body="&lt;p&gt;In one of my Geography books, the following sentence is written:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Though weathering aids erosion, it is not a pre-condition for erosion to take place.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can I justify this? Almost all the forms of erosion that I know happens on weathered rocks. Do we have any examples of erosion without weathering? As weathering means to &lt;strong&gt;strip off or to uncover&lt;/strong&gt;, and erosion means &lt;strong&gt;to transfer&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far I came up with one example: Blast eruption of volcano makes small stones and pebbles, which could be carried by waves, rivers etc.&lt;/p&gt;&#xA;" OwnerUserId="14742" LastActivityDate="2020-01-20T07:43:01.690" Title="Erosion without weathering?" Tags="|geography|erosion|weathering|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15913" PostTypeId="2" ParentId="15912" CreationDate="2019-01-09T13:42:00.717" Score="1" Body="&lt;p&gt;The case of a volcano blasting solid rock into smaller bits and pieces will generally still be regarded as weathering. Nonetheless, for your case to justify this statement, you could consider a glacier scouring through a fjord or rocky valley. However, the fact that particles have been 'stripped off' before they have engaged in transport processes by definitions means that something is weathered. Only in case of the glacier it does not act as a precondition&lt;/p&gt;&#xA;" OwnerUserId="13870" LastActivityDate="2019-01-09T13:42:00.717" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15914" PostTypeId="2" ParentId="15912" CreationDate="2019-01-09T14:06:02.470" Score="10" Body="&lt;p&gt;Your concept of weathering is erroneous. It is not uncovering or stripping off material. &lt;a href=&quot;https://en.wikipedia.org/wiki/Weathering&quot; rel=&quot;noreferrer&quot;&gt;Weathering&lt;/a&gt; is a very slow process of breaking down rocks, soil &amp;amp; minerals, &lt;em&gt;in-situ&lt;/em&gt;, via contact with the Earth's atmosphere, water &amp;amp; biological organisms. This can also involve heat &amp;amp; pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Erosion&quot; rel=&quot;noreferrer&quot;&gt;Erosion&lt;/a&gt;, as you state, involves the moving of material. This can happen due to the action of running water, the impact of water via waves on coastal environments, wind or glaciers dislodging grains of geological material irrespective of whether it is weathered or not. Landslides are another form of erosion. &lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-01-09T14:06:02.470" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15915" PostTypeId="2" ParentId="15909" CreationDate="2019-01-09T14:16:36.297" Score="4" Body="&lt;p&gt;The situation in the southern hemisphere is identical to the northern hemisphere, but they occur at different times of the year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the northern hemisphere the arctic circle is situated at 66.5 degrees North. Likewise in the southern hemisphere, the antarctic circle is situated at 66.5 degrees South. Between each circle and its respective pole &lt;a href=&quot;https://sciencing.com/many-hours-daylight-summer-8196183.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;24 hours of daylight&lt;/a&gt; will occur for about a month or more from the onset of the summer solstice for each hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The southernmost settlement in South America is &lt;a href=&quot;https://en.wikipedia.org/wiki/Southernmost_settlements&quot; rel=&quot;nofollow noreferrer&quot;&gt;Puerto Williams&lt;/a&gt; which is located at 56 degrees 56 minutes South. This is a lot further north than the antarctic circle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To experience 24 hour days in the southern hemisphere you will have to be in Antarctica, as is evident from this picture, acquired from &lt;a href=&quot;https://en.wikipedia.org/wiki/Antarctic_Circle&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9oI19.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9oI19.png&quot; alt=&quot;Antarctic Circle: 66.5 degrees south, dashed blue line&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Australian base at &lt;a href=&quot;https://en.wikipedia.org/wiki/Research_stations_in_Antarctica&quot; rel=&quot;nofollow noreferrer&quot;&gt;Casey&lt;/a&gt; is just outside of the antarctic circle having a latitude of 66 degrees 17 minutes South. However, the Chilean base at Carvajal is just inside the antarctic circle with a latitude of 67 degrees 45 minutes South.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2019-01-11T16:54:13.107" LastActivityDate="2019-01-11T16:54:13.107" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15916" PostTypeId="1" CreationDate="2019-01-09T15:23:18.777" Score="1" ViewCount="278" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Guideline on handling cluster issues :&lt;/strong&gt; The original Environmental  Impact Assessment ( EIA ) notification does not provide for the procedure to handle cluster situation, which has been proposed in this guideline and will become part of the notification. One EIA will be prepared for one cluster irrespective of number and size of mining leases in that cluster, if the area is more than 5 hectares. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Taken from a book am reading on Environment, the author isn’t internationally known but I will still mention his name, Shankar. &lt;/p&gt;&#xA;" OwnerUserId="14699" LastEditorUserId="2470" LastEditDate="2019-01-09T19:10:09.530" LastActivityDate="2019-02-08T20:01:35.297" Title="What is cluster situation with respect to sand mining?" Tags="|minerals|rivers|environmental-protection|mining|ore|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15917" PostTypeId="1" CreationDate="2019-01-09T16:03:28.790" Score="4" ViewCount="122" Body="&lt;p&gt;I am fascinated at the rapid growth of Glacier Bay Glacier from 1600 to 1750, along with its rapid retreat from 1750 to 1900. I am interested in the local weather conditions during these times. What are the likely variations in the local temperatures and precipitation during these periods. How much colder was the average local temperature to create no retreat during the summer peak heat during the growth period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm guessing the glacier grew for 8 months of the year, it was growing &amp;amp; moving seaward at a rate of 5-6 meters a day for a 100 years. How different and noticeably different would the climate have felt by citizen of near by Juneau if living during the rapid growth period of 1650. Was it harsh winter conditions almost year round, or ? How much did the average day time high change from what it is today. Can an &lt;em&gt;average&lt;/em&gt; year round change in temperature of .5C or 2.5 or 4.5 degrees cause this huge change in glacier behaviour. What was going on with global climate at this time to cause this amazing growth during the maunder minimum? Why the temperature change during this period?&lt;/p&gt;&#xA;" OwnerUserId="14745" LastActivityDate="2019-02-10T09:01:40.327" Title="Weather conditions to create significant glacier growth" Tags="|climate-change|glaciology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15918" PostTypeId="2" ParentId="15916" CreationDate="2019-01-09T19:07:39.080" Score="1" Body="&lt;p&gt;Cluster in this situation refers to a grouping or a number of mining operations within a giving area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sometimes deposits of minerals with sand deposits is such that a number of smaller deposits is created instead of one larger more continuous deposit. When this happens it sometimes makes more sense to mine the deposits as separate pits instead of one large pit. The result is a cluster of mines within a given region/area.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-01-09T19:07:39.080" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15919" PostTypeId="1" AcceptedAnswerId="15920" CreationDate="2019-01-09T19:10:49.150" Score="0" ViewCount="1236" Body="&lt;p&gt;The freezing point of water is 32°F. If it rains at a temperature lower than that, it will snow. However, let's say we dig a deep hole not filled with water that goes like 10,000 feet below sea level. The pressure will be greater there, but if the temperature is high enough to cause the rain to boil, what happens to the rain? Does it just evaporate before hitting the ground?&lt;/p&gt;&#xA;" OwnerUserId="14398" LastEditorUserId="14398" LastEditDate="2019-01-09T22:26:05.193" LastActivityDate="2019-01-12T05:12:39.500" Title="What happens if it rains above the boiling point of water?" Tags="|meteorology|hypothetical|rain|extreme-weather|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15920" PostTypeId="2" ParentId="15919" CreationDate="2019-01-09T22:21:44.277" Score="3" Body="&lt;p&gt;Pressure and temperature are not all the same when going up vertically. See &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Earth#/media/File:Comparison_US_standard_atmosphere_1962.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;average temperature and pressure profiles.&lt;/a&gt;  The evaporation of any liquid has a pressure-dependent equilibrium point, see &lt;a href=&quot;https://en.wikipedia.org/wiki/Water_(data_page)#Phase_diagram&quot; rel=&quot;nofollow noreferrer&quot;&gt;the phase diagram of water&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Clausius%E2%80%93Clapeyron_relation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Clausius-Clapeyron&lt;/a&gt; for a mathematical description of the equilibrium point.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I assume that you mean with 212°F (100°C) the temperature at 1 bar level. Then water would tend to evaporate as it goes through the surrounding hot atmosphere. How quickly this happens depends on the temperature of the droplets and their size, i.e. the conditions of their formation.&lt;br&gt;&#xA;If the free-fall speed is higher than the evaporation speed, then droplets would still hit the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course this is a hypothetical scenario, as if the ground is at 100°C, then the atmospheric layers where droplets &lt;strong&gt;could&lt;/strong&gt; form will be some 20-30°C colder (so minimum at 160°F). Which means they will not form in the first place.&lt;br&gt;&#xA;Which means it would not rain if you assume the ground temperature is 212°F.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2019-01-09T22:21:44.277" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15921" PostTypeId="1" AcceptedAnswerId="15958" CreationDate="2019-01-09T22:53:40.987" Score="5" ViewCount="126" Body="&lt;p&gt;I took those photos in a hurry (sorry, the color is a bit off due to low light, the first picture is the most distorted one).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It struck me that the discolorations seem to follow the fissures in the rock. &#xA;Could somebody explain me what caused the red-brown colorations along the grooves?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;IIRC the bedrock shown is glacially polished Rhyolite, location is the &lt;a href=&quot;https://www.google.it/maps/place/Gleifkirche/@46.4551142,11.249813,725m&quot; rel=&quot;noreferrer&quot;&gt;&quot;Gleif church in Eppan, Italy&quot;&lt;/a&gt;. Further research told me that the glacial polishing happened in the &lt;a href=&quot;https://en.wikipedia.org/wiki/W%C3%BCrm_glaciation&quot; rel=&quot;noreferrer&quot;&gt;Würm glaciation&lt;/a&gt;, ending 12000 years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fAixa.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fAixa.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yofAE.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yofAE.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MNyki.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MNyki.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4YZR1.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4YZR1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14748" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T07:44:41.897" LastActivityDate="2019-08-28T07:44:41.897" Title="What caused those colorations in bedrock?" Tags="|bedrock|weathering|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15922" PostTypeId="1" AcceptedAnswerId="15923" CreationDate="2019-01-10T04:39:37.410" Score="10" ViewCount="1999" Body="&lt;p&gt;This &lt;a href=&quot;https://twitter.com/esa_es/status/1080751887677378560&quot; rel=&quot;noreferrer&quot;&gt;tweet&lt;/a&gt; from the European Space Agency (ESA)'s Spanish account show a striking photo of a round, flat, &quot;space-ship-shaped&quot; cloud in an otherwise completely clear sky. The stars are out so I assume this is at night, possibly with a Moon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could this be real? If so, what kind of cloud is it? and how can it appear out in the open?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dlMTp.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dlMTp.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorDisplayName="user12525" LastEditDate="2019-08-27T10:54:55.660" LastActivityDate="2023-11-07T00:01:11.397" Title="What is this spaceship-shaped cloud?" Tags="|meteorology|clouds|orography|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="15923" PostTypeId="2" ParentId="15922" CreationDate="2019-01-10T05:09:04.663" Score="12" Body="&lt;p&gt;The image shown is a &lt;a href=&quot;https://en.wikipedia.org/wiki/Lenticular_cloud&quot; rel=&quot;noreferrer&quot;&gt;lenticular cloud&lt;/a&gt;, a type of cloud often observed around significant topographical features such as the mountain peaks shown in the photo. Depending on the local atmospheric moisture, they can occur on their own (as in this case), apart from other cloud features.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All cloud growth depends on the condensation of water resulting from air being cooled as it is &lt;a href=&quot;https://www.ess.uci.edu/~yu/class/ess5/Chapter.6.cloud.all.pdf&quot; rel=&quot;noreferrer&quot;&gt;lifted vertically&lt;/a&gt; by some forcing mechanism. However, these clouds are an exception to more typical cloud growth, which depends on the atmosphere having a tendency (or &lt;a href=&quot;https://digitalatlas.cose.isu.edu/clima/imaging/clddev.htm&quot; rel=&quot;noreferrer&quot;&gt;instability&lt;/a&gt;) for air to continue rising - and thereby condensing more liquid water - once forced upward.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Following the initial source cited above, lenticular clouds form in environments that are stable (i.e., not conducive) to these vertical motions, so upward motion is entirely driven by air forced over an obstacle - in this case, mountain terrain. From a horizontal view, the vertical motion forced by this obstacle commonly takes the form of a persistent wave pattern: &lt;a href=&quot;https://i.stack.imgur.com/gfuKv.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gfuKv.jpg&quot; alt=&quot;orographic waves&quot;&gt;&lt;/a&gt; &lt;a href=&quot;http://apollo.lsc.vsc.edu/classes/met130/notes/chapter6/lift_topo_wave.html&quot; rel=&quot;noreferrer&quot;&gt;image source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This occurs downwind of the terrain feature, with clouds forming over the portion of the wave featuring upwards vertical motion. This becomes extremely evident when viewing &lt;a href=&quot;https://youtu.be/3P46yC6lma0?t=12&quot; rel=&quot;noreferrer&quot;&gt;time-lapse videos&lt;/a&gt; of this phenomenon.&lt;/p&gt;&#xA;" OwnerUserId="14078" LastActivityDate="2019-01-10T05:09:04.663" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="15924" PostTypeId="1" CreationDate="2019-01-10T14:07:06.253" Score="1" ViewCount="32" Body="&lt;p&gt;I am currently trying to use absolute precipitation forecasts for medium term range (3wk-2mth). As no models of NOAA have absolute precipitation on this timerange, my idea was to compute those forecasts by adding the forecasted anomaly to the long term average. However, I was not able to find the long term average.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Is this approach right?&lt;/li&gt;&#xA;&lt;li&gt;Where can I find a grib or DODS resource with the long term averages?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="6700" LastActivityDate="2019-01-10T14:07:06.253" Title="Computation of absolute precipitation forecast from precipitation anomaly forecast in NOAA CFSv2" Tags="|precipitation|climate-models|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15925" PostTypeId="2" ParentId="15907" CreationDate="2019-01-10T23:23:28.623" Score="8" Body="&lt;p&gt;You need to calculate the change in the moment of inertia of the Earth and use conservation of angular momentum. In the case of &lt;em&gt;eg.&lt;/em&gt; a large dam, (most of) the water will ultimately come from the sea, effectively removing a thin layer of water. The contribution of the removed water to the moment of inertia depends on the distance from the rotation axis and hence on the latitude. This is a fairly simple calculation if we assume the world is all ocean. A more precise calculation would have to take into account the shapes of the oceans. You also need the moment of inertia of the earth, which depends on the density as a function of depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The moment of inertia of the lake is &lt;span class=&quot;math-container&quot;&gt;$m(R\cos L)^2$&lt;/span&gt; and the moment of inertia of a spherical shell is &lt;span class=&quot;math-container&quot;&gt;$\frac{2}{3}mR^2$&lt;/span&gt;, where m is the mass of water, &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; is the Earth's radius and &lt;span class=&quot;math-container&quot;&gt;$L$&lt;/span&gt; is the latitude of the lake (30.82305 degrees for Three Gorges). The relative change in the moment of inertia of the earth is then&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{mR^2(\cos^2 L - \frac{2}{3})}{I}$$&lt;/span&gt;&#xA;(where &lt;span class=&quot;math-container&quot;&gt;$I$&lt;/span&gt; is the Earth's moment of inertia, &lt;a href=&quot;https://en.wikipedia.org/wiki/Rotational_energy&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;span class=&quot;math-container&quot;&gt;$8.04×10^{37}$&lt;/span&gt; kg·m&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt;&lt;/a&gt;) or&#xA;&lt;span class=&quot;math-container&quot;&gt;$$1.97×10^{-11}(\cos^2 L - \frac{2}{3}) .$$&lt;/span&gt;&#xA;Multiplying by the number of microseconds in a day (&lt;span class=&quot;math-container&quot;&gt;$8.64 \times 10^{10}$&lt;/span&gt;) gives: &#xA;&lt;span class=&quot;math-container&quot;&gt;$$1.7(\cos^2 L - \frac{2}{3}) = 1.7 × 0.071 = 0.12\,\mu\text{s}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why the difference from NASA's &lt;span class=&quot;math-container&quot;&gt;$0.06$&lt;/span&gt; ? Note that the expression changes sign at  &lt;span class=&quot;math-container&quot;&gt;$\cos^2 L = \frac{2}{3}$&lt;/span&gt; or &lt;span class=&quot;math-container&quot;&gt;$L ≈ 35$&lt;/span&gt; degrees (fairly close to the latitude of Three Gorges). The Earth will actually speed up if the lake is at high latitudes and slow down if it is at the equator. The &lt;span class=&quot;math-container&quot;&gt;$\frac{2}{3}$&lt;/span&gt; term comes from the &quot;all ocean&quot; assumption. I presume NASA took into account the shapes of the oceans and got a more accurate value for this term.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6298" LastEditDate="2019-01-14T09:23:44.513" LastActivityDate="2019-01-14T09:23:44.513" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15927" PostTypeId="2" ParentId="15917" CreationDate="2019-01-11T08:14:03.777" Score="4" Body="&lt;p&gt;Hold on, you're talking about growth of the glacier's tongue, not necessarily the whole glacier itself. To my best knowledge, flow dynamics of ice in glaciers still are not wholly understood, meaning we do not really know, why sometimes glaciers seem to grow so rapidly (protruding their tongue).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A prerequisite is the presence of enough ice in the growth-area of the glacier (growth area is the part above the snowline), meaning above average snowfalls in the years or even decades before the easier observable tongue growth. More snow compacts to more ice, generating more pressure on the whole glacier body, finally causing the outflow of the tongue.&lt;/p&gt;&#xA;" OwnerUserId="14194" LastActivityDate="2019-01-11T08:14:03.777" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15931" PostTypeId="1" CreationDate="2019-01-11T15:26:35.083" Score="1" ViewCount="119" Body="&lt;p&gt;I downloaded an edmo dataset of 1 ensemble of the cera-20c model. I want to convert these data, which are in [m], to mm/month. Further specifications: 0.125/0.125 grid, -29/30/-30/31 area. Example of the data (see picture) of total precipitation January 1980:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FdqHM.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FdqHM.png&quot; alt=&quot;the month January of 1980 of the dataset&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My method: Taking the average of these numbers multiplying by 31 (days in January) and 1000 (from m to mm) gives me 299 mm for January. But this does not seem right. It seems overestimated. I hope you can help me with the right answer. I read something about multiplying by the scale factor and adding the add_offset. But the scale factor is so small (10E-7) that all numbers approximately similar.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks a lot in advance for any ideas.&#xA;Louwrens Timmer&lt;/p&gt;&#xA;" OwnerUserId="14759" LastEditorUserId="14759" LastEditDate="2019-01-13T23:19:37.313" LastActivityDate="2019-01-13T23:19:37.313" Title="How can I convert a CERA-20C total precipitation dataset of &quot;monthly means of daily means' (edmo) to mm/month?" Tags="|meteorology|atmosphere|precipitation|climate-models|reanalysis|" AnswerCount="0" CommentCount="13" ContentLicense="CC BY-SA 4.0" />
  <row Id="15933" PostTypeId="2" ParentId="15919" CreationDate="2019-01-11T17:44:22.937" Score="2" Body="&lt;p&gt;It will depend on how the temperature and humidity change as the raindrops approach the bottom of the column. If the air is hot and dry, the drops will evaporate. If it's hot and humid enough, they may survive to hit the bottom. Remember that the boiling point of water rises as pressure increases!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your statement &quot;If it rains at a temperature lower than [32 F], it will snow&quot; is a bit inaccurate. It can still &lt;em&gt;rain&lt;/em&gt; at colder temperatures if there's a warmer layer of air aloft. (This can originate as normal rain, or as snow that melts as it falls through warmer air.) Conversely, it can snow when the ground-level temperature is above freezing, as long as the temperature aloft is &lt;em&gt;below&lt;/em&gt; freezing. Finally, we have sleet (rain which freezes as it falls through colder air) and graupel (supercooled water that freezes onto snowflakes, forming little fluffy ice balls). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can also get freezing rain, which is &lt;em&gt;supercooled&lt;/em&gt; liquid water falling as rain -- it's liquid, but below the freezing point at ambient pressure. This rain will freeze when it hits a solid object, creating a layer of ice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By analogy to this last process, there could be &lt;em&gt;superheated&lt;/em&gt; water that still falls as liquid, but bursts into steam as soon as it hits a surface. We wouldn't see that under normal conditions, because it would be falling through air that isn't saturated, so it would undergo evaporative cooling. In your deep, hot, and eventually humid hole, though, it might well be possible -- I'm not sure what would &lt;em&gt;produce&lt;/em&gt; such superheating, but I can't rule it out.&lt;/p&gt;&#xA;" OwnerUserId="13324" LastEditorUserId="13324" LastEditDate="2019-01-12T05:12:39.500" LastActivityDate="2019-01-12T05:12:39.500" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15934" PostTypeId="1" AcceptedAnswerId="15936" CreationDate="2019-01-11T19:08:54.200" Score="4" ViewCount="282" Body="&lt;p&gt;An &lt;a href=&quot;https://www.dailymail.co.uk/sciencetech/article-6558285/Little-Ice-Age-hundreds-years-ago-cooling-bottom-Pacific-researchers-find.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;article about ocean temperature history/modeling&lt;/a&gt; has this plot:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IGUtQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IGUtQ.jpg&quot; alt=&quot;Purty colors&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where the units are given as &lt;code&gt;cK&lt;/code&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;cK&lt;/code&gt; does not seem to be &lt;a href=&quot;https://en.wikipedia.org/wiki/Template:Convert/list_of_units/temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;a standard temperature unit&lt;/a&gt; and &lt;a href=&quot;https://www.google.com/search?q=units%20of%20temperature%20list%20%22cK%22&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google searches return millions of results that don't seem relevant&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;While it might be &amp;quot;fun&amp;quot; if the temperatures shown were Kelvin, centi-Kelvins, or even Celsius, that seems unlikely as we are all still alive.&lt;/p&gt;&#xA;&lt;h3&gt;So, what is &lt;code&gt;cK&lt;/code&gt; as shown on the graphic, and how do you convert the temperatures shown to degrees Celsius?&lt;/h3&gt;&#xA;&lt;p&gt;If the axis is really some delta temperature, what is the zero point?&lt;/p&gt;&#xA;" OwnerUserId="5272" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-01-11T20:07:55.037" Title="What kind of temperature unit is &quot;cK&quot;?" Tags="|oceanography|temperature|climatology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15936" PostTypeId="2" ParentId="15934" CreationDate="2019-01-11T19:34:44.903" Score="6" Body="&lt;p&gt;It actually is the common &lt;em&gt;centi-&lt;/em&gt; prefix, but applied to temperature &lt;em&gt;changes&lt;/em&gt; in units of Kelvins rather than absolute temperatures. The research as quoted by the Daily Mail obscures this by simplifying the results for a general audience.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The analyses and results are much more clearly described in the &lt;a href=&quot;http://science.sciencemag.org/content/363/6422/70&quot; rel=&quot;noreferrer&quot;&gt;original refereed journal article&lt;/a&gt;, which clearly refers to changes in temperature - see in particular the discussion of their Fig. 1 (reproduced below), which explicitly refers to rates of temperature change of 0.1 and 0.02 °C at depths below 2000 m over the previous century, corresponding to cK contours of ~10 and near zero in the corresponding section of that figure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, the contours in the figure quoted by the Daily Mail represent changes in temperature between measurements made in the 1870s and the early 2000s, in units of 0.01 K (or equivalently, 0.01 °C).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8nWKh.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8nWKh.jpg&quot; alt=&quot;Fig 1&quot;&gt;&lt;/a&gt;&#xA;Figure 1 from Gebbie and Huybers (2019), &lt;a href=&quot;https://doi.org/10.1126/science.aar8413&quot; rel=&quot;noreferrer&quot;&gt;https://doi.org/10.1126/science.aar8413&lt;/a&gt; - reproduced here for non-commercial use.&lt;/p&gt;&#xA;" OwnerUserId="14078" LastEditorUserId="14078" LastEditDate="2019-01-11T20:07:55.037" LastActivityDate="2019-01-11T20:07:55.037" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15937" PostTypeId="2" ParentId="6800" CreationDate="2019-01-11T19:45:33.833" Score="-10" Body="&lt;p&gt;Please consider that the strength of the magnetic field determines atmospheric density and pressure. Planets with strong magnetic fields have thick oceans and atmosphere, while planets with very weak magnetic fields have no oceans and very thin atmosphere. That's because hydrogen atoms from solar winds are attracted and condensed around magnetic fields and the strength of the MF dictates the atmospheric density, and atmospheric pressure dictates the ocean levels.&#xA;Mars for example shows signs of erosion as it had oceans and atmosphere but when the dynamo inside went through a hard double flip (most probably) and slowed down so much, cooled down so much that it could never recover, the atmosphere was blown away by solar winds, oceans boiled away, etc. Mars's gravity field doesn't explain how it lost its oceans and atmosphere when Earth still has them. Mars's gravity field didn't change, it lost its magnetic field. &#xA;Jupiter's bigger moons have thick ocean frozen at the surface (frozen because of distance from the Sun) but they are smaller than Mars and have strong magnetic fields.. So size and amount of pressure inside doesn't necessarily mean a stronger magnetic field,, what all planets and terrestrial moons with strong MF have in common is an inner core that makes a small orbit around the center of the planet/moon, because of tidal effect (gravitational pull) from a big body nearby. For example, Earth's inner core is attracted by our big and heavy Moon, and it's not spinning in the dead center of Earth but has a small orbit around the center, planar to the Moon's orbit, and it stirs the soup inside as Earth spins on itself. It keeps the soup warm and generates friction thus electric currents, thus electromagnetism.&#xA;Jupiter's moons have their inner core drawing a larger orbit inside as they (moons) spin on themselves, their core is off-centered toward Jupiter.&#xA;Our Moon is actually the big core of an ancient planet that collided with our former (smaller) planet about 4.5 Billion years ago. Their liquid matter blobbed together and the smaller core bounced from the explosion as just the right speed and angle to stabilize on orbit, and the little bit of liquid matter on it cooled fast with a tide towards Earth, witch is the heavier side of the Moon that always point to Earth. With time it gathered the splash from the collision. It's a big metal core with a thin crust and this is why it rings like a bell and the craters are all shallow.&#xA;So anyway.. we're very lucky to have the Moon because otherwise Earth would be like Mars right now. Mars doesn't have a big moon so its core just spins in the center and doesn't generate enough friction. Maybe it had a moon before, with an unstable orbit destined to swing away..&#xA;Now, why does our MF tend to flip every 12-13000 years, or twice every Great Year (Precession of the Equinoxes, a 26000-year Milankovitch Cycle when the Earth's spin tilt axis wobbles 360*)?&#xA;I think it's because there are 2 critical tilt angles, during the Precession,, where the spin inertia of the iron currents, plus the angle of the inner core's orbit (planar to the Moon's orbit, not the same angle as the Earth's rotation axis),, plus the difference in speed (earth spins on itself in one day while the Moon takes 27.3 days to go around Earth),,, produce electric currents that don't agree with the magnetic field orientation and forces it to either reverse or migrate..&#xA;(to visualize this, have a pot of sauce that represents Earth, a wooden spoon that represents the inner core and an imaginary moon that goes around the pot in 27 days. Turn the pot of sauce continually to simulate earth's rotation and imagine it's tilted 23.4*,, and place the spoon (core) off-centered in the pot and tilt the spoon to simulate the difference in angles of the Earth's spin and of the moon's orbit plane. As you spin the pot, continuously, slowly orbit the spoon in the same time as your imaginary moon,, and see the currents you're generating in the sauce.. Then slowly change the tilt of the spoon to simulate Earth's precession.. It sounds fun? Do this to really get a visual)..&#xA;Now during the reversal or excursion process, the convection currents need to reorient and mix and slow down, producing less friction thus less electromagnetism, so the atmosphere gets thinner and filters out less solar and cosmic radiation. Less friction also means less heat produced inside the planet, so the volume of the planet has to shrink a little bit, and that explains the spike in seismic and volcanic activity around the Peak.&#xA;What explains how ocean levels can drop 400ft? Well if the atmosphere is thin during the day, then raw solar radiation evaporates tons and tons of ocean surface and during the night it gets very cold so all the moisture in the air has to precipitate within hours. Most of it falls back in the oceans and on land, and some of it becomes atmosphere and is eventually blown away by solar winds. That explains the biblical amounts of precipitations and erosion (Grand Canyon fills up and deserts turn into seas and the northern atmosphere is covered with very thick glaciers, big mammals flash frozen, etc).. Flash frost is also explained by rapid atmospheric density drop when a CME impacts the already thin atmosphere and temporarily blows some of it away: pressure drops fast and flash-freezes everything at the surface.&#xA;A thin atmosphere also explains the number of meteorite impacts because meteors rain down every day but usually burn with friction, blow up into small bits and only tiny bits of metal reach the ground,, but when the atmosphere is thin, meteors have much less friction so better chances to hit the ground in bigger chunks.&#xA;Those 2 critical tilt angles during the Precession are:&#xA;one as we enter Leo (the stronger magnetic Excursions (double flips) like the Gothenburg Magnetic Excursion 13000 years ago and the Leschamp Magnetic Excursion 40000 years ago, etc)&#xA;and the other one as we enter Aquarius (the mild semi-reversals (also calles Excursions) like now, or like the Lake Mungo Magnetic Excursion 26000 years ago,, etc).&#xA;This is all over ancient civilizations calendars, like the Mayan calendar, etc. For Example, the Sphinx was pointing Leo 13000 years ago, but was probably built 11000 years ago after the Younger Dryas warming, as a big immortal monument to commemorate this strong event that almost got us extinct.&#xA;Also, one important principal, heat generated inside the planet goes up slowly through the crust, then slowly raises up in the oceans, then joins the heat on the surface from solar radiations, and that heat has to go up in the atmosphere to reach the space vacuum.. The stronger the magnetic field and the thicker the oceans and the atmosphere,,, and the slower heat can reach up into space. Vice-versa, the thinner the oceans and atmosphere and the faster heat can reach up into space..&#xA;We could say that at Peak, a typical day would be like: super windy as almost unfiltered solar radiation expands the air very rapidly,, then all day would feel like a super hot sauna with tons of melting and floods, and evaporation would look like a steam engine.. Then, as the Sun starts to set the sky veils with thick condensation. Shortly after, deluges and super flash floods, turning into super ice storm breafly, then meters of snow until the air is dry and very cold, like -50C (moisture can stay in the air up to -20C but lower than that, all humidity is already deposited, so all moisture in the air has to deposit within a few hours)... Then, in the morning it starts all over again. Sometimes when there is a CME impact, it gets worse.&#xA;OK, I'll stop here, will elaborate more if there is interest.. Please give me feedback,, wherever I'm wrong and how I should rethink.. Thanks&lt;/p&gt;&#xA;" OwnerUserId="14761" LastEditorUserId="14761" LastEditDate="2019-01-12T00:14:51.647" LastActivityDate="2019-01-12T00:14:51.647" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="15941" PostTypeId="1" CreationDate="2019-01-12T06:52:00.900" Score="3" ViewCount="67" Body="&lt;p&gt;I am new to this field, recently started working on landslide monitoring mainly in signal processing part. I have the following questions? &#xA;1.Will each land slide and every vibration have p wave, s wave and surface wave ?&#xA;2.How do we segregate these three waves from the signals we would receive from our field?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks in advance&lt;/p&gt;&#xA;" OwnerUserId="14764" LastEditorDisplayName="user1066" LastEditDate="2019-01-12T08:27:07.643" LastActivityDate="2019-01-12T08:27:07.643" Title="Difference between landslide waves and earth quake waves" Tags="|geophysics|seismology|seismic|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15943" PostTypeId="1" CreationDate="2019-01-12T13:18:25.743" Score="2" ViewCount="486" Body="&lt;p&gt;I recently observed a phenomenon during a nighttime flight over upper Midwest of USA-specifically over Marquette, MI.  In what is a lightly populated area, I observed several very large rectangular regions glowing bright orange yellow, as if they were illuminated.  I believe they were drainage ponds from iron mines.  I theorize that the moon was at a critical angle and I saw a speculat reflection from these orange ponds that can be seen on google earth at 46°24'22&quot;N 87°31'01&quot;W · 1,244 ft.  Have you ever observed or heard of such a thing?  It was approx 01hr on Jan 11, 2019. &lt;img src=&quot;https://i.stack.imgur.com/hMTcS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="14767" LastEditorUserId="6467" LastEditDate="2019-01-12T13:30:33.220" LastActivityDate="2021-11-16T03:16:46.313" Title="Glowing Orange lakes seen from airplane at night" Tags="|water|ground-truth|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15944" PostTypeId="2" ParentId="15943" CreationDate="2019-01-12T15:11:33.397" Score="6" Body="&lt;p&gt;The orange lakes are most likely tailing dams, also known as tailings storing facilities given that they located near an open pit iron ore mine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once iron ore has been mined it is usually sent to a processing plant to increase the grade (amount) of iron in the product the mine exports. It does this by removing as much waste material as possible. Sometimes the waste is low grade iron ore (very low concentration of iron);.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Usually the ore is crushed, ground and treated chemically. What is deemed as waste (tailings) is sent/dumped to a tailings dam. There will always be an amount of unrecoverable iron in the tailings which will give the tailings a reddish color. Low Moon angles may accentuate the red or orange coloring.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-01-12T15:11:33.397" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15946" PostTypeId="2" ParentId="9978" CreationDate="2019-01-12T22:25:53.637" Score="6" Body="&lt;p&gt;One needs to calculate the change in the moment of inertia of the Earth and use conservation of angular momentum (the rotation period is proportional to the moment of inertia). Most of the water will ultimately come from the oceans, effectively removing a thin layer of water.&lt;/p&gt;&#xA;&lt;p&gt;Jerry Mitrovica discusses this effect (in reverse) in a &lt;a href=&quot;https://nautil.us/issue/62/systems/why-our-intuition-about-sea_level-rise-is-wrong-rp&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nautilus interview&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Is water moving off glaciers, slowing the Earth’s rotation, this time analogous to a figure skater putting arms out?&lt;/strong&gt;&lt;br /&gt;&#xA;Right. Glaciers are mostly near the axis. They’re near the North and South Poles and the bulk of the ocean is not. In other words, you’re taking glaciers from high latitudes like Alaska and Patagonia, you’re melting them, they distribute around the globe, but in general, that’s like a mass flux toward the equator because you’re taking material from the poles and you’re moving it into the oceans. That tends to move material closer to the equator than it once was.&lt;br /&gt;&#xA;&lt;strong&gt;So the melting mountain glaciers and polar caps are moving bulk toward the equator?&lt;/strong&gt;&lt;br /&gt;&#xA;Yes. Of course, there is ocean everywhere, but if you’re moving the ice from a high latitude and you’re sticking it over oceans, in effect, you’re adding to mass in the equator and you’re taking mass away from the polar areas and that’s going to slow the earth down.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The contribution of the removed water to the moment of inertia depends on the distance from the axis and hence on the latitude. This is a simple calculation if we assume the world is all ocean.&lt;/p&gt;&#xA;&lt;p&gt;The moment of inertia of the lake is &lt;span class=&quot;math-container&quot;&gt;$m(R\cos L)^2$&lt;/span&gt; and the moment of inertia of a spherical shell is &lt;span class=&quot;math-container&quot;&gt;$\frac{2}{3}mR^2$&lt;/span&gt;, where m is the mass of water, &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; is the Earth's radius and &lt;span class=&quot;math-container&quot;&gt;$L$&lt;/span&gt; is the latitude of the lake (&lt;span class=&quot;math-container&quot;&gt;$30.82305$&lt;/span&gt; degrees for Three Gorges). The relative change in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Rotational_energy&quot; rel=&quot;nofollow noreferrer&quot;&gt;moment of inertia &lt;span class=&quot;math-container&quot;&gt;$I$&lt;/span&gt; of the Earth&lt;/a&gt; is then&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{mR^2}{I}(\cos^2 L - \frac{2}{3}) &#xA;= \frac{39 \times 10^{12} \times(6.37 \times 10^{6})^2}{8.04×10^{37}}(\cos^2 L - \frac{2}{3})$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$=1.97×10^{-11}(\cos^2 L - \frac{2}{3})$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Multiplying by the number of microseconds in a day (&lt;span class=&quot;math-container&quot;&gt;$8.64 \times 10^{10}$&lt;/span&gt;) gives&#xA;&lt;span class=&quot;math-container&quot;&gt;$$1.7(\cos^2 L - \frac{2}{3}) = 1.7 × 0.071 = 0.12$$&lt;/span&gt;&#xA;microseconds.&lt;/p&gt;&#xA;&lt;p&gt;Why the difference from NASA's &lt;span class=&quot;math-container&quot;&gt;$0.06$&lt;/span&gt; ? Note that the expression changes sign at &lt;span class=&quot;math-container&quot;&gt;$\cos^2 L = \frac{2}{3}$&lt;/span&gt; or &lt;span class=&quot;math-container&quot;&gt;$L ≈ 35$&lt;/span&gt; degrees (pretty close to the latitude of Three Gorges). The Earth will actually speed up if the lake is at high latitudes and slow down if it is at the equator. The &lt;span class=&quot;math-container&quot;&gt;$\frac{2}{3}$&lt;/span&gt; term comes from the &lt;em&gt;&amp;quot;all ocean&amp;quot;&lt;/em&gt; assumption.&lt;/p&gt;&#xA;&lt;p&gt;As I understand &lt;a href=&quot;http://www.leapsecond.com/pages/lod/2010-Chapanov-Gambis-Long-Variations-Earth-Rotation.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt;, the &lt;span class=&quot;math-container&quot;&gt;$\frac{2}{3}$&lt;/span&gt;  term should be multiplied by &lt;span class=&quot;math-container&quot;&gt;$\frac{1.414}{1.38}$&lt;/span&gt; to account for the shape of the oceans (search in the PDF for those numbers), resulting in &lt;span class=&quot;math-container&quot;&gt;$0.09$&lt;/span&gt; microseconds.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="4849" LastEditDate="2022-08-09T12:00:36.693" LastActivityDate="2022-08-09T12:00:36.693" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15948" PostTypeId="1" AcceptedAnswerId="15954" CreationDate="2019-01-13T00:47:24.243" Score="11" ViewCount="767" Body="&lt;p&gt;Popular news has several articles linking back to the news article in Nature &lt;a href=&quot;https://www.nature.com/articles/d41586-019-00007-1&quot; rel=&quot;noreferrer&quot;&gt;Earth’s magnetic field is acting up and geologists don’t know why&lt;/a&gt; which discusses the need for an early update to the World Geomagnetic Model.&lt;/p&gt;&#xA;&lt;p&gt;However my question is about one line found in the Independent's &lt;a href=&quot;https://www.independent.co.uk/news/science/magnetic-north-pole-moving-arctic-siberia-canada-earth-navigation-ships-a8724426.html&quot; rel=&quot;noreferrer&quot;&gt;Planet’s erratic magnetic field forces emergency update to global navigation system&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The shift they observed was so large it was on the verge of exceeding the acceptable limit for navigation errors.&lt;/p&gt;&#xA;&lt;p&gt;To account for this, scientists at the British Geological Survey and the US National Oceanic and Atmospheric Administration (NOAA) are issuing an unprecedented emergency update to the model.&lt;/p&gt;&#xA;&lt;p&gt;They have fed in the latest data, &lt;strong&gt;including an unexpected geomagnetic pulse that took place beneath South America in 2016,&lt;/strong&gt; to ensure the system is more accurate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What is the nature, and underlying cause of the &amp;quot;unexpected geomagnetic pulse that took place beneath South America in 2016&amp;quot;?&lt;/p&gt;&#xA;&lt;p&gt;AKA &lt;em&gt;geomagnetic jerk.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-04-23T02:46:07.233" Title="What is the nature of the &quot;unexpected geomagnetic pulse that took place beneath South America in 2016&quot;?" Tags="|geomagnetism|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15949" PostTypeId="1" CreationDate="2019-01-14T02:52:57.413" Score="1" ViewCount="26" Body="&lt;p&gt;I am reading a groundwater pollution vulnerability study by Mark Angle of the Ohio Dpet. of Natural Resources (ODNR) for my county. The model used to assess the groundwater vulnerability for the county is called DRASTIC. The model was developed by the National Water Well Association for the EPA. I am simply curious as to whether or not the DRASTIC model is still a widely used tool in the world of hydrogeology? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further, the study says that the model is designed to be accurate for map-able units of 100 acres or greater in size. Could DRASTIC be improved upon to model areas on a per 50 acre basis or less? Is there even any reason to?&lt;/p&gt;&#xA;" OwnerUserId="14308" LastActivityDate="2019-01-14T02:52:57.413" Title="The DRASTIC groundwater vulnerability model and it's relevance today" Tags="|models|groundwater|pollution|hydrogeology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15950" PostTypeId="5" CreationDate="2019-01-14T11:00:38.420" Score="0" Body="&lt;p&gt;The things we see from planes or in images can sometimes mislead us. Not only can remote sensing technology leave artifacts, humans have the uncanny need to see patterns where there aren't any.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to discover the truth about what we are seeing, it's often necessary to go to the place itself, or at least use our knowledge of the area, or of Earth processes, or the image interpretation skills of professionals.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2019-01-14T11:00:38.420" LastActivityDate="2019-01-14T11:00:38.420" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15951" PostTypeId="4" CreationDate="2019-01-14T11:00:38.420" Score="0" Body="Ground-based reference measurements to aid remote sensing for Earth science" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2019-01-14T11:00:38.420" LastActivityDate="2019-01-14T11:00:38.420" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15954" PostTypeId="2" ParentId="15948" CreationDate="2019-01-14T16:01:24.700" Score="14" Body="&lt;p&gt;The &quot;geomagnetic pulse&quot; here refers to a series of academic works studying the Earth's core such as &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1002/2013JB010604&quot; rel=&quot;noreferrer&quot;&gt;this open access article&lt;/a&gt; (other related articles require scientific journal subscriptions to read).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geomagnetic pulses have been associated with &lt;a href=&quot;https://en.wikipedia.org/wiki/Geomagnetic_jerk&quot; rel=&quot;noreferrer&quot;&gt;&quot;geomagnetic jerks&quot;&lt;/a&gt;. &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1002/2015GL065501&quot; rel=&quot;noreferrer&quot;&gt;A jerk was reported (yay for open access again) to have occurred in 2014&lt;/a&gt;, the 2016 pulse under South America is believed to be related to this, both events having been measured and identified after the fact.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The magnetic field is always changing - a &quot;pulse&quot; is a quicker-than-normal (few year) acceleration of magnetic field change in time, in a region at the surface of the Earth's outer core (magnetic field is generated within the core).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A &quot;jerk&quot; is a quick change (few months) of the rate at which magnetic field changes at Earth's surface, making something like a 'V' shape if you plot the field against time at a given location.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The idea is that a pulse occurs at the core, and jerks are an effect seen at the surface just before and after the peak of the pulse, as the field change ramps up and down. &lt;em&gt;The underlying cause of this is not known&lt;/em&gt;, and we only identify them after they've occurred, so they're currently unpredictable. That said this behaviour is apparently part of the core's repertoire, and pulses and jerks have been observed before.&lt;/p&gt;&#xA;" OwnerUserId="14123" LastEditorUserId="6031" LastEditDate="2019-01-24T23:11:18.823" LastActivityDate="2019-01-24T23:11:18.823" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15955" PostTypeId="2" ParentId="14743" CreationDate="2019-01-14T16:45:45.500" Score="0" Body="&lt;p&gt;From what I understand, Volcanoes eruption energy can be calculated with Kinetic Energy with finding the mass (kg) of lava &amp;amp; debris being fired and the speed of which the debris is shot out to find it in amount of energy (joules)&lt;/p&gt;&#xA;" OwnerUserId="14696" LastActivityDate="2019-01-14T16:45:45.500" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15956" PostTypeId="1" AcceptedAnswerId="15981" CreationDate="2019-01-14T17:36:13.837" Score="5" ViewCount="398" Body="&lt;p&gt;Today I learnt in college that marine sediments can be used to reconstruct the climate up to 500 million years back. I find that number very strange because in another class we learnt that the ocean floor &quot;recycles&quot; every few million years as a result of plate tectonics, and that the oldest ocean floor is 200 million years old. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I asked the lecturer about this, but he said he did not know. So I was hoping anyone here could tell me how many years old the climate we can recover through marine sediment cores is and why. &lt;/p&gt;&#xA;" OwnerUserId="14779" LastActivityDate="2019-01-18T23:08:51.780" Title="How much climate history can be reconstructed using marine sediment cores?" Tags="|climate|earth-history|sedimentology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15957" PostTypeId="1" AcceptedAnswerId="15968" CreationDate="2019-01-14T17:44:15.047" Score="2" ViewCount="120" Body="&lt;p&gt;For this, I am trying to understand if it is a measure of force (Newtons) or energy (Joules ) of when fissures are created, Fissures are where the ground is being torn up either by volcanic ventilation, or otherwise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So whether it is measured in force or energy, I wish to know what is the best equation for this phenomenon to occur.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the information I have that would further this is the area is 20.58 m^2, the depth is 30,000 m. and it happened in just a second.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I thought it would be used for Tensile Strength with Silicon with the yield strength of 180 MPa. &lt;/p&gt;&#xA;" OwnerUserId="14696" LastActivityDate="2019-01-23T23:17:11.237" Title="Fissure Energy/Force Equation" Tags="|plate-tectonics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15958" PostTypeId="2" ParentId="15921" CreationDate="2019-01-14T22:41:36.833" Score="3" Body="&lt;p&gt;This answer is based on a cursory look at the 1:50000 &lt;a href=&quot;http://www.isprambiente.gov.it/Media/carg/26_APPIANO/Foglio.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Foglio Appiano&lt;/a&gt;, from the Geologic Map of Italy (in Italian Language only, as far as I can tell). As I pointed out in comment, I intend it as just a start for further investigations, which should be done with more detailed geological works and possibly more field work. I'd recommend contacting the office of the &lt;a href=&quot;http://www.provincia.bz.it/costruire-abitare/edilizia-pubblica/rilevamento-geologico-e-geotematico.asp&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geological survey of the Provincia di Bolzano&lt;/a&gt; as they certainly know the area well and may be able to answer on the phone or by email.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is what I think, based on my cursory look.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cross section C goes ~E-W just north of the town of Cornaiano, relatively close to the location of the Church, which is just West of San Michele (based on Google map link); I indicated its approximate whereabouts with yellow circle in the figure below. It looks like the rocks in your picture could be an outcrop of the ORA formation (in orange in the figure), a Rhyolitic tuff of the &lt;em&gt;Atesino volcanic group&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sOnjX.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sOnjX.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also the &lt;em&gt;Schema tettonico&lt;/em&gt; below (look for Appiano) shows the &lt;em&gt;Atesino volcanic group&lt;/em&gt; and is in contact with a very faulted sedimentary section (&lt;em&gt;Successione sedimentaria permocenozoica&lt;/em&gt;); I'd say geothermal fluid circulation through these fractures causing hydrothermal alteration at surface is a plausible explanation for the coloration you captured.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/jB5Z0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jB5Z0.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="144" LastActivityDate="2019-01-14T22:41:36.833" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="15967" PostTypeId="1" CreationDate="2019-01-15T15:39:39.753" Score="1" ViewCount="421" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AWBut.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AWBut.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/0s18J.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0s18J.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/GEwPs.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GEwPs.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/b2mjW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/b2mjW.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;I found this piece of quartz at Benbo Mt Co. Sligo Ireland.There are many Megaliths in this area in the Dartry Mt range.Its 3 inches in length and appears to have been fashioned as a tool.I found it about a third of the way up Benbo Mountain.The pointed end appears to have been used to chip maybe other rocks.&lt;/p&gt;&#xA;" OwnerUserId="12459" LastEditorUserId="12459" LastEditDate="2019-01-15T15:41:42.180" LastActivityDate="2019-01-15T15:41:42.180" Title="Is this milky quartz a stone age tool?" Tags="|archaeology|research|" AnswerCount="0" CommentCount="13" ClosedDate="2019-01-18T07:05:05.927" ContentLicense="CC BY-SA 4.0" />
  <row Id="15968" PostTypeId="2" ParentId="15957" CreationDate="2019-01-15T16:31:31.860" Score="4" Body="&lt;p&gt;Force is used to (try to) move objects apart. Energy is expended as the objects move and thereby separate. In a pure physics sense, until an object moves, absolutely no work energy is expended. You can push on a wall all you want with as much force as you want but, unless the wall moves, you do no work.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A stress-strain curve of a materials is a map of force to cause a deformation. The area under the curve is a map of the energy to cause the deformation. Up to the yield stress, the area is resilience. This is the energy expended to cause elastic deformation of the material. Because the stress strain curve is a straight line in the elastic region, the functional form of resilience &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$R = \sigma_y \epsilon_y / 2 = \sigma_y^2 / 2E $$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$\sigma_y$&lt;/span&gt; is yield stress, &lt;span class=&quot;math-container&quot;&gt;$\epsilon_y$&lt;/span&gt; is yield strain, and &lt;span class=&quot;math-container&quot;&gt;$E$&lt;/span&gt; is Young's (elastic) modulus.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A further stress-strain function happens up to breaking. The total area under the stress-strain curve to break is toughness. The stress strain curve is not linear in this region. Integration methods are required.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fissure forms because the material breaks, not because it reaches the end of its elastic deformation. The force needed is the obtained from the true breaking stress of the material. The energy required is obtained as the toughness of the material.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ductile materials have a yield, a tensile, and a breaking stress. The tensile strength is the point where the material begins to neck. Think chewing gum stretched ... necking is where the gum thins.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Perfectly brittle materials have no yield. They just fail after elastic deformation. The toughness is the resilience in this case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many cases for materials that show only modest if any ductility and no necking assign the yield stress as the failure stress and ignore breaking stress. The toughness is greater than resilience, but the distinction is not a hard one. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Resilience and toughness may appear to have the same units as stress (e.g. Pa = N/m&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt;). In reality, a better unit designation for both is energy per unit volume (e.g. J/m&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt;).&lt;/p&gt;&#xA;" OwnerUserId="13534" LastEditorUserId="13534" LastEditDate="2019-01-23T23:17:11.237" LastActivityDate="2019-01-23T23:17:11.237" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15971" PostTypeId="1" AcceptedAnswerId="16003" CreationDate="2019-01-17T09:03:15.097" Score="3" ViewCount="479" Body="&lt;p&gt;This circular rain pattern was observed in Sydney’s rain radar today. It remained for the entire loop, wiggling around a bit but mostly staying in the same place.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fact that it’s centred around the radar made me suspect it is some kind of artifact. Is that the case? Or this this real? If it’s real, why would it look like that?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kxZXN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kxZXN.jpg&quot; alt=&quot;rain&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-01-22T09:44:39.947" Title="Circular rain cloud observed in rain radar" Tags="|meteorology|precipitation|radar|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15973" PostTypeId="1" CreationDate="2019-01-17T11:54:49.333" Score="2" ViewCount="1664" Body="&lt;p&gt;I want to run wrf chem with ERA 5. I followed this post &lt;a href=&quot;https://dreambooker.site/2018/04/20/Initializing-the-WRF-model-with-ERA5/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://dreambooker.site/2018/04/20/Initializing-the-WRF-model-with-ERA5/&lt;/a&gt;. Everything works fine unless I add surface pressure to surface data list(SP or 134.128). metgrid.exe threw out &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Processing domain 1 of 1&#xA; Processing 2015-06-01_00&#xA;    FILE&#xA;    PRES&#xA;ERROR: Error in ext_pkg_write_field&#xA;application called MPI_Abort(MPI_COMM_WORLD, 0) - process 0&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Any help would be highly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="14796" LastEditorUserId="14796" LastEditDate="2019-01-18T20:55:01.337" LastActivityDate="2019-01-18T20:55:01.337" Title="run the WRF model using ERA5" Tags="|atmosphere-modelling|wrf|era|wrf-chem|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15976" PostTypeId="1" CreationDate="2019-01-18T12:56:13.303" Score="0" ViewCount="65" Body="&lt;p&gt;I downloaded &lt;a href=&quot;http://chrsdata.eng.uci.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;PERSIANN-CCS&lt;/a&gt; for the region of Pawlowdar, Kazakhstan and this has stripes all over my downloaded data.&lt;br /&gt;&#xA;For another AOI in Kazakhstan I do not have this problem. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone of you have any idea where these artefacts are coming from?&lt;br /&gt;&#xA;I did not process the data at all.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/USWxb.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/USWxb.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14802" LastEditorUserId="14802" LastEditDate="2019-01-18T14:08:20.463" LastActivityDate="2019-01-18T15:21:21.117" Title="Artefacts in PERSIANN-CCS data" Tags="|precipitation|remote-sensing|rainfall|earth-observation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15977" PostTypeId="2" ParentId="15976" CreationDate="2019-01-18T15:21:21.117" Score="2" Body="&lt;p&gt;The &lt;em&gt;Further reading&lt;/em&gt; link brings you to &lt;a href=&quot;http://chrs.web.uci.edu/SP_activities01.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;The PERSIANN System Fine Resolution Precipitation Estimates Using PERSIANN-Cloud Classification System&lt;/a&gt; which shows that the data is merged with signals coming from both geostationary and polar/near polar satellites. My guess is that it's just banding in one of these datasets (probably from that second group of satelites).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried to look at raw image data from these satellites (to illustrate my assumption), but I bump into sites that are affected by the current US government shutdown, resulting in e.g. incorrect and expired CSS certificates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you can dig up these raw images in a later stage, you'll probably be able to map the width of those bands to the aperture of the satellite.&lt;/p&gt;&#xA;" OwnerUserId="595" LastActivityDate="2019-01-18T15:21:21.117" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15979" PostTypeId="2" ParentId="15973" CreationDate="2019-01-18T18:24:16.930" Score="1" Body="&lt;p&gt;Did you use the right Vtable? That error message is saying that the soil temperature variable is missing/couldn't be read.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2019-01-18T18:24:16.930" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15980" PostTypeId="2" ParentId="2966" CreationDate="2019-01-18T21:16:23.263" Score="4" Body="&lt;p&gt;The region on Earth that display the smallest contrast between seasons is that in the vicinity of the Equator, because of the smaller changes in solar irradiation. Therefore, equatorial areas do not experience cold and warm seasons. Instead, most equatorial areas usually have wet and dry seasons as they shift in and out of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Intertropical_Convergence_Zone&quot; rel=&quot;nofollow noreferrer&quot;&gt;Intertropical Convergence Zone (ITCZ)&lt;/a&gt;, which is basically a band of clouds and heavy rain that encircles the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Taking this into account, a good starting point to discovering areas with the least seasonal contrast (i.e. one season) is to find places near the Equator where the ITCZ varies less.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following is a figure showing the maximum northward and southward locations of the ITCZ during the year (taken from &lt;a href=&quot;https://en.wikipedia.org/wiki/Intertropical_Convergence_Zone#/media/File:ITCZ_january-july.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; but I added the equatorial line in red).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ftTKs.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ftTKs.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By looking at how the ITCZ changes, it looks the place you are seeking for is in northern Brazil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is just rough thoerization though. We can go further by looking at the actual data. As there is not a weather station at every location on Earth, our best hope is to use reanalysis data. This is basically data computed using all available weather station data to figure out atmospheric variables all around the world. One of the most reliable reanalyses is ERA-interim covering the period 1979-2018. This data can be accessed and queried at &lt;a href=&quot;https://climexp.knmi.nl/selectfield_rea.cgi?id=d17099be003bf17970040ea12c50ad61&quot; rel=&quot;nofollow noreferrer&quot;&gt;KNMI Climate Explorer&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using the analysis tools there, I've computed standard deviation of the monthly precipitation over the whole Earth for each of the 40 years cover by the dataset. Then, I've averaged those 40 years to see where the precipitation has the least variation through the year (within that 1979-2018 period). I downloaded the data to better visualize and analyze it and it looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mKHdq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mKHdq.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As was to be expected, the smaller variation happens in the drier places. This is because the total precipitation is small and thus the standard deviation will be small as well. For example, if in a dessert it rains only 10 mm in any month, the maximum possible precipitation variation will be 10 mm, despite still being a big contrast between seasons. But in a tropical forest it might rain 400 mm in the driest month and 420 mm in the wettest, a difference of 20 mm, yet still have a negligible seasonal contrast.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All that is to say that if we care about seasonal variability, it makes more sense if we show the standard deviation above then normalized by the total precipitation, which looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eqJkd.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eqJkd.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As we anticipated looking at the changes in the ITCZ, the most apparent equatorial area with minimal contrast between wet and rainy seasons is in northern Brazil/southern Colombia/northeastern Peru. But there are also some lesser areas in northern Congo in Africa and Indonesia in Asia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.climatemps.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;climatemps.com&lt;/a&gt; have a nice map where you can click stations around the world and see climate stats. If you click stations there that are in the area encircled by the blue blob near northern Brazil in the above figure, you will indeed see several pretty flat temperature and precipitation curves. For instance for Iquitos, Peru:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dsHZt.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dsHZt.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To better compare with the example of Andagoya, Colombia provided in other answers, here is the same data but with the axis scaled to match the Andagoya figure:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/M2DIH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/M2DIH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So those areas of equatorial South America and Africa appear to indeed be some of the least varying places through the year on Earth.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="6298" LastEditDate="2019-01-20T12:57:15.630" LastActivityDate="2019-01-20T12:57:15.630" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15981" PostTypeId="2" ParentId="15956" CreationDate="2019-01-18T22:53:24.983" Score="2" Body="&lt;p&gt;The oldest &lt;em&gt;in situ&lt;/em&gt; marine sediments recovered by IODP (International Ocean Drilling Program; formerly ODP and DSDP) was (from memory) Late Triassic (so ca. 200 to 230 Ma) and it is as old as &lt;em&gt;in situ&lt;/em&gt; marine sediments go, since indeed, as the marine crust gets older, it gets denser and thus is more prone to be subducted. However we do have older marine sediments, that were lifted during various orogenies and that were somewhat metamorphosed but are still viable for paleoclimatic studies (to some reduced extent of course). These lifted and metamorphosed sediments (along with the crust below them and even the upper mantle dragged along) are referred to as ophiolites, and they indeed date as far back as the earliest Phanerozoic (so 500 Ma). As most of the climatic information we are getting from them depends on the planktonic or benthic eukaryotic activity at the time of sedimentation, we cannot really go further back with these.&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2019-01-18T23:08:51.780" LastActivityDate="2019-01-18T23:08:51.780" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="15982" PostTypeId="2" ParentId="15956" CreationDate="2019-01-18T22:56:05.723" Score="2" Body="&lt;p&gt;The oldest ocean floor in the ocean is no more than 200 million years old. Ocean floor sometimes subducts into the Earth but other times gets lifted to eventually become solid land. Whale fossils have been found in the Andes, deep sea creature fossils in the Alps, and perhaps most famously, bizarre sea life fossils from the mid-Cambrian in the Burgess Shale in the Canadian Rockies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fossils embedded in what was sea floor, along with the sediment around those fossils, provide information regarding paleoclimate. One key set of paleoclimate proxies are various isotope and chemical ratios in fossilized seashells. There are lots of fossilized seashells, spanning in age from fairly recent geological past to 500 million years ago.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2019-01-18T22:56:05.723" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15983" PostTypeId="1" AcceptedAnswerId="16534" CreationDate="2019-01-18T23:11:00.933" Score="1" ViewCount="217" Body="&lt;p&gt;Geological/Planetary differentiation is one of those topics that gets glossed over in intro Geo courses. We know that differentiation occurs over deep time (and will never end) and is a result of the heating of rock. Heating in this case can be driven by collision, accretion (planet formation), and radioactivity. So, we know that the Earth, Mars, and Moon have all differentiated. On the other hand, smaller asteroids will never differentiate. Are there any set/known size requirements on a body before it attains a high level of differentiation like the Earth? &lt;/p&gt;&#xA;" OwnerUserId="14308" LastActivityDate="2019-03-20T19:32:25.273" Title="Geological Differentiation: variables and size requirement" Tags="|geology|planetary-formation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15985" PostTypeId="1" CreationDate="2019-01-19T08:29:08.503" Score="4" ViewCount="40" Body="&lt;p&gt;I understand that we have zircon crystals that prevent entering or leaving of nuclide or lead after forming. But how cand we understand what was the initial ratio? &lt;/p&gt;&#xA;" OwnerUserId="14807" LastActivityDate="2019-01-19T08:29:08.503" Title="How do people determine initial ratio of the parent nuclide and daughter product in radiometric dating?" Tags="|geology|geophysics|radioactivity|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15986" PostTypeId="1" CreationDate="2019-01-19T09:13:26.740" Score="-2" ViewCount="610" Body="&lt;p&gt;Is there any consensus about the conjecture that gravitational force on Earth may have changed significantly over geological time; and in particular in periodic increase associated with mass extinctions such as at the KPg boundary? For example, would transitions in the composition of atmospheric gases favouring the predominance of lighter gases (e.g. Nitrogen) and water over heavier gases (oxygen, CO2), arguably incorporated into terrestrial biomass, or evidence of a suspension in mountain-building, and the effect of subsidence be considered to corroborate such a hypothesis.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is especially intriguing in this regard is that the process of non-avian dinosuar extinction which might reasonably be attributed to such an increase in gravity occurred over a much longer period than that in which the conditions following an asteroid impact would have persisted.  Possibly the asteroid veered into Earth as a result of such an increase; possibly smaller avian dinosaurs more readily survived such transitions.&lt;/p&gt;&#xA;" OwnerUserId="14808" LastEditorUserId="-1" LastEditDate="2019-01-23T08:22:48.593" LastActivityDate="2023-07-30T03:53:05.413" Title="Variations in Gravity over Time" Tags="|mass-extinction|gravity|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15987" PostTypeId="2" ParentId="15986" CreationDate="2019-01-19T09:58:23.873" Score="11" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Is there any consensus about the conjecture that gravitational force on Earth may have changed significantly over geological time;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;No, Earth's gravity did not change significantly over time. Yes, Earth's mass increases because of meteorites and decreases because of loss of some atmospheric gases to space, but it is &lt;a href=&quot;https://earthscience.stackexchange.com/a/4481/725&quot;&gt;extremely negligible&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;and in particular in periodic increase associated with mass extinctions such as at the KPg boundary?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;No. There is no evidence for any periodic increase or decrease that coincides with mass extinctions.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;For example, would transitions in the composition of atmospheric gases favouring the predominance of lighter gases (e.g. Nitrogen) and water over heavier gases (oxygen, CO2&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Earth's mass is about 6×10&lt;sup&gt;24&lt;/sup&gt; kg. The atmosphere's mass is about 6×10&lt;sup&gt;18&lt;/sup&gt; kg. The atmosphere's mass is one &lt;em&gt;millionth&lt;/em&gt; of the entire mass of the earth. Any variations in that are going to be absolutely negligible when considering the effect of the total gravity of the earth.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Possibly the asteroid veered into Earth as a result of such an increase;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Just as a change in gravity can deflect an asteroid's trajectory to Earth, it could deflect an asteroid's trajectory that was going to hit earth anyway, &lt;em&gt;away&lt;/em&gt; from earth. Big planets like Jupiter get hit more not only because of their greater gravity, but simply because they're a much bigger target.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="2470" LastEditDate="2022-05-22T08:39:44.310" LastActivityDate="2022-05-22T08:39:44.310" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15989" PostTypeId="1" CreationDate="2019-01-20T05:42:34.593" Score="4" ViewCount="2132" Body="&lt;p&gt;I want to purchase a piece of smoky quartz crystal, but am not sure if it is irradiated.  Is there a way to tell if it has been irradiated?  Thank you.&lt;/p&gt;&#xA;" OwnerUserId="14811" LastActivityDate="2022-10-29T22:04:11.790" Title="How do you tell if smoky quartz has been irradiated?" Tags="|geology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15992" PostTypeId="1" CreationDate="2019-01-20T17:34:31.950" Score="10" ViewCount="1410" Body="&lt;p&gt;I had a question concerning the nature of continental plates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When looking at the Eurasian Plate today, for the most part, there is one solid fragment of the Earth's crust. However, having had a look at maps detailing prehistoric Earth, this isn't always the case. Throughout the entire Phanerozoic Eon, Eurasia has been a collection of different landmasses gradually merging together. Baltica, Kazakhstania, all the various regions of East and South-East Asia. Yet, today, only India and Arabia are still situated upon separate plates. All others no longer possess any divisions between them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is this the case? I was under the assumption that it was only oceanic plates that submerge into the mantle due their density. I though that when continental plates collide, neither continent submerges, forming mountains. Shouldn't there still be distinct tectonic plates?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any answers would be greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="14814" LastActivityDate="2019-12-05T13:51:37.610" Title="Do Tectonic Plates Merge?" Tags="|plate-tectonics|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15994" PostTypeId="1" AcceptedAnswerId="15996" CreationDate="2019-01-21T05:57:16.403" Score="9" ViewCount="58184" Body="&lt;p&gt;A few months ago, I witnessed something off the coast of Florida that I have never seen in my life. From my apartment, from about 10PM - 12AM, I saw pretty much continuous cloud to cloud lightning. I don't really remember how many strikes a second it was, or if it was once every couple seconds, but there was never a time when there was not one or more lightning strikes in the air. I had a video but unfortunately the file is corrupted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any name of this phenomena, and how common is it?&lt;/p&gt;&#xA;" OwnerUserId="6072" LastEditorUserId="595" LastEditDate="2019-01-21T11:59:31.293" LastActivityDate="2020-12-22T11:14:19.727" Title="Continuous lightning for over an hour; is this phenomenon common and does it have a name?" Tags="|meteorology|lightning|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="15995" PostTypeId="1" AcceptedAnswerId="15997" CreationDate="2019-01-21T06:07:19.613" Score="2" ViewCount="198" Body="&lt;p&gt;Wind chill works by removing the layer of heated air around your body. However in a hot area, say a desert, wouldn't the air around be hotter than your body or at least much closer to it than cold air? In that case, how much would wind chill actually affect your temperature loss?&lt;/p&gt;&#xA;" OwnerUserId="14818" LastActivityDate="2019-01-21T07:30:46.333" Title="Does wind chill work in deserts?" Tags="|meteorology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="15996" PostTypeId="2" ParentId="15994" CreationDate="2019-01-21T06:32:11.703" Score="3" Body="&lt;p&gt;In Norwegian we call it kornmo (grain ripener); it happens in the late summer at a distance of more than 20 km so there is no sound.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The English translation is: &quot;sheet lightning - heat lightning - summer lightning&quot;. I am not sure if this covers the meaning we have for it in Norwegian; it is said that Thor, the god of thunder, swung his hammer over the fields to get the grain ready for harvest.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This type of lightning is at more than 20km from the viewer and often 10-20 times this distance from you. It is really beautiful to see it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This type of lightning happens high up in the atmosphere so one needs good viewing conditions to be able to see it. I do not think it is rare in itself; what is rare is the the atmospheric conditions that allow us to see it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I guess this does not answer your question fully so I hope others post their answers too.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="2958" LastEditDate="2019-01-21T12:19:27.797" LastActivityDate="2019-01-21T12:19:27.797" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="15997" PostTypeId="2" ParentId="15995" CreationDate="2019-01-21T07:30:46.333" Score="2" Body="&lt;p&gt;As you state, &lt;a href=&quot;https://en.wikipedia.org/wiki/Wind_chill&quot; rel=&quot;nofollow noreferrer&quot;&gt;wind chill&lt;/a&gt; &quot;is the cooling of a body due to the passing-flow of lower temperature air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because of this, wind chill only occurs when then air had capacity to absorb heat from a body - thus chilling the body. The capacity of air to absorb heat from a body is dependent on the temperature difference between the air and the body, and the humidity of the air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In determining the ability of the air to absorb heat , &lt;a href=&quot;https://en.wikipedia.org/wiki/Wet-bulb_temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;the wet bulb temperature&lt;/a&gt; must be used, in conjunction with the &lt;a href=&quot;https://en.wikipedia.org/wiki/Dry-bulb_temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;dry bulb&lt;/a&gt;. Wind chill and [heat index] (&lt;a href=&quot;https://en.wikipedia.org/wiki/Heat_index&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Heat_index&lt;/a&gt;) are related.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a hot environment, such as a very hot day in a desert, a wind chill factor usually will usually not exist. Under such conditions is it possible to a body to over heat and experience heat stress and &lt;a href=&quot;https://en.wikipedia.org/wiki/Hyperthermia&quot; rel=&quot;nofollow noreferrer&quot;&gt;hyperthermia&lt;/a&gt;, which can lead to death. Also, one has to be careful so that &lt;a href=&quot;https://en.wikipedia.org/wiki/Windburn&quot; rel=&quot;nofollow noreferrer&quot;&gt;wind burn&lt;/a&gt; doesn't occur.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-01-21T07:30:46.333" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="15998" PostTypeId="2" ParentId="15986" CreationDate="2019-01-21T07:53:43.407" Score="-4" Body="&lt;p&gt;There are two parts to the question, the first concerning the conjecture that there may have been significant changes, more particularly increases in Earth's 'gravity'--thus acceleration due to gravity g-- over geological time, the second some speculation about the implication of relatively acute changes in gravity in such mass extinction events as that arising at the KPg boundary (and not excluding the idea that such acute increases might indeed be periodic in geological history; as in the earlier instance of the 'great rainforest collapse' in which several factors may have been implicated militating against the capacity for huge vegetative organisms to sustain height under phototropic impetus). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With respect to the first part, and in answer to the response to it that no evidence of such increase exists, might I humbly suggest that demise of non-avian dinosaurs in particular, massive creatures on a boggy Earth, does in fact of itself constitute reasonable evidence of such increase regardless of suppositions about the cause of that change in gravity; more especially since dinosaur extinction cannot reasonably be ascribed entirely to the effects of the Chicxulub impact, even in association with the atmospheric effects of the Deccan traps.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These latter hypotheses require the scarcely credible conclusion that not one single solitary breeding pair of young dinosaurs of the billions extant at the time were able to endure a year or two of privation, subsisting on hay in some cosy valley somewhere; or have managed to sustain themselves through epigenetic adaptation in an atmosphere corrupted by volcanic ash. Any reasonable analysis of the evidence of this extinction clearly suggests the involvement of another factor; and some such increase in gravity, especially if it were able to be otherwise corroborated, should be far more seriously considered than is apparent from the almost hysterical indignation evinced at this site. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding the cause or mechanism of such an abrupt (periodic) increase in g, this is indeed a difficult question; but its answer most certainly does not devolve upon speculation about the mass of the Earth whose estimation depends primarily on assumptions in gravitational theory contingent upon measures of g.  The objection that gravity cannot have changed because the Earth's mass has not substantially varied is obviously circular and invalid. One is left to imagine various scenarios in which proximity to the Sun or to bodies such as the Moon may have changed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In considering the composition of atmospheric gases as corroborative evidence for such an increase in gravity (and noting the nature of the course of such changes), the relative mass of the atmosphere as a whole is immaterial. The issue is whether an increase in g may have favoured the incorporation of heavier gases like CO2 and O2 into carboniferous biomass or mineral oxides as the function of their molecular weights, conversely allowing lighter gases and H2O to escape into the atmosphere through displacement. This is clearly a difficult and contentious point, but it warrants proper reasoned scientific consideration, rather than the puerile repudiation of the entire sense of the question by those who seem not to have understood it; and indeed to have responded rather dismally by viciously down-voting it under the cloak of privilege.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Possibly I might have framed the question differently, or even asked separate questions had I not been perhaps naively encouraged by the belief that those purporting to be scientists at this site would be capable of accommodating several related lines of inquiry simultaneously, and of responding to a well-considered question asked in good faith with proper diligence.&lt;/p&gt;&#xA;" OwnerUserId="14819" LastEditorUserId="-1" LastEditDate="2019-01-22T08:15:45.077" LastActivityDate="2019-01-22T08:15:45.077" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16000" PostTypeId="1" AcceptedAnswerId="16001" CreationDate="2019-01-21T15:04:05.833" Score="83" ViewCount="56698" Body="&lt;p&gt;&lt;strong&gt;What is the location on Earth that is closest to the Sun?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've seen this question asked many times, and answered in varied and contradictory ways:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The most common answer is “the summit of &lt;strong&gt;Chimborazo volcano&lt;/strong&gt; in Ecuador”. This volcano is the &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2772/farthest-point-from-the-center-of-the-earth/2777#2777&quot;&gt;point on Earth's surface that is furthest from the center of Earth&lt;/a&gt;, and that is then equated to being the closest to the Sun.&#xA;This is very commonly spoken of around the Chimborazo volcano area and among the people involved with tourism there (&lt;a href=&quot;https://shawnwashere.wordpress.com/2009/10/30/climbing-to-the-spot-on-earth-closest-to-the-sun-day-388/&quot; rel=&quot;noreferrer&quot;&gt;here is an example of this answer&lt;/a&gt;)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Others argue that it is &lt;strong&gt;Cayambe volcano&lt;/strong&gt; in Ecuador, it being the highest point along the equatorial line (&lt;a href=&quot;https://www.quora.com/What-is-the-place-on-Earth-closest-to-the-Sun&quot; rel=&quot;noreferrer&quot;&gt;answer example&lt;/a&gt;).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Others say &lt;strong&gt;Mount Everest&lt;/strong&gt; in Nepal/China because it is the highest point on Earth (&lt;a href=&quot;http://www.funtrivia.com/askft/Question21808.html&quot; rel=&quot;noreferrer&quot;&gt;example&lt;/a&gt;).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;And others argue it is &lt;strong&gt;Sairecabur volcano&lt;/strong&gt; in Chile/Bolivia, because it is the highest point at the latitude which is closest to the Sun on January 5th, when the perihelion happens (i.e. the point in Earth's orbit that is closest to the sun) (&lt;a href=&quot;https://www.quora.com/What-is-the-place-on-Earth-closest-to-the-Sun&quot; rel=&quot;noreferrer&quot;&gt;example&lt;/a&gt;).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;A fifth answer, with the same logic as the previous, is &lt;strong&gt;Licancabur volcano&lt;/strong&gt; in Chile/Bolivia, which quite as close to the latitude of the perihelion but is significantly higher than Sairecabur.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is the correct answer and why?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What place on Earth is closest to the Sun?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="6298" LastEditDate="2019-01-21T23:28:48.013" LastActivityDate="2024-03-10T10:06:13.480" Title="What place on Earth is closest to the Sun?" Tags="|geography|earth-system|astronomy|orbit|geodesy|" AnswerCount="7" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="16001" PostTypeId="2" ParentId="16000" CreationDate="2019-01-21T15:32:45.113" Score="154" Body="&lt;p&gt;This is an interesting question, but it lacks a key factor that is crucial to the answer: &lt;strong&gt;TIME&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The point on Earth closest to the Sun &lt;strong&gt;varies through time&lt;/strong&gt;, so the question can be asked about any moment in time, or over periods of time. Let's analyze the factors involved.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At any given moment in time, the point on Earth's surface that is closest to the Sun is what is called the “&lt;a href=&quot;https://en.wikipedia.org/wiki/Subsolar_point&quot; rel=&quot;noreferrer&quot;&gt;subsolar point&lt;/a&gt;”. This point corresponds to the point on the surface that intersects the imaginary line that connects the center of the Earth to the center of the Sun. In other words, the subsolar point correspond to the point on Earth surface where the sunlight hits the Earth perpendicular to the ground, therefore, a vertical object would project no shadow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aCoRYm.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aCoRYm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(image from &lt;a href=&quot;https://en.wikipedia.org/wiki/Subsolar_point#/media/File:Subsolar_point.png&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia: subsolar point&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The longitude of the subsolar point corresponds to that of the meridian experiencing &lt;a href=&quot;https://en.wikipedia.org/wiki/Noon#Solar_noon&quot; rel=&quot;noreferrer&quot;&gt;solar noon&lt;/a&gt;. Over Greenwich (longitude 0°) that happens at the actual noon, and as the Earth rotates 15° every hour, that will happen one our later (at 13:00 h UTC) at longitude 15° W, two hours later (at 14:00 h UTC) at longitude 30° W, and so on. In general terms, you can use the following formula for the subsolar point longitude (&lt;span class=&quot;math-container&quot;&gt;$\text{SSP}_{\text{long}}$&lt;/span&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\text{SSP}_{\text{long}} = \left(\text{UTC} -12\right)*15°$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a simplified formula, but accurate enough for our purpose. Let's take as an example the following date&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;July 20, 1969, at 20:17 UTC&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In that moment, the longitude of the subsolar point was 124° 15' West:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$(20+(17/60)-12)*15°=124.25°=124°15'$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finding the latitude of the subsolar point is a bit more complicated, we need to know the &lt;a href=&quot;https://en.wikipedia.org/wiki/Declination&quot; rel=&quot;noreferrer&quot;&gt;declination&lt;/a&gt; of the Sun. Declination is the equivalent of latitude for celestial coordinates. For that, use &lt;a href=&quot;https://www.esrl.noaa.gov/gmd/grad/solcalc/solareqns.PDF&quot; rel=&quot;noreferrer&quot;&gt;a formula&lt;/a&gt;, &lt;a href=&quot;http://www.reuk.co.uk/wordpress/solar/solar-declination/&quot; rel=&quot;noreferrer&quot;&gt;a table&lt;/a&gt;, or a online calculator like the &lt;a href=&quot;https://www.esrl.noaa.gov/gmd/grad/solcalc/azel.html&quot; rel=&quot;noreferrer&quot;&gt;NOAA Solar Position Calculator&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just enter the date, and even that the location doesn't matter here, we need to select “Enter Lat/Long --&gt;” to be allowed to enter the offset to UTC as 0, otherwise the time won't be interpreted as UTC time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From there we can find that the solar declination for our example date is 20.58° (20° 34') which corresponds to the latitude of the subsolar point: 20° 34' North.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, on July 20, 1969, at 20:17 UTC, the subsolar point was at 20° 34' N, 124° 15' W, which is somewhere between Mexico and Hawaii. That was the point on Earth closest to the Sun at that moment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Now, what would happen if there were a very tall mountain close to the subsolar point? Would that mountain be closer to the Sun?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer is: probably. It depends on how far and how much higher it is relative to the subsolar point.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can do a quick calculation based on the following diagram (in this approximation we assume that Earth is spherical, that the sun is infinitely far away and other simplifications)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pmO4X.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pmO4X.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From there we have&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$r-r'=\Delta H$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$D = r ~ \theta$&lt;/span&gt; (&lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; in radians)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\frac{r'}{r}=\cos(\theta)$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;After some algebra you can write that the extra height &lt;span class=&quot;math-container&quot;&gt;$\Delta H$&lt;/span&gt; needed to be as close to the Sun as the subsolar point is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\Delta H = r \left(1-\cos\left(\frac{D}{r}\right)\right)$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where &lt;span class=&quot;math-container&quot;&gt;$D$&lt;/span&gt; is the distance and &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; is Earth's radius (in this case makes sense to use the &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth&quot; rel=&quot;noreferrer&quot;&gt;equatorial radius&lt;/a&gt; of 6378.1 km)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we plot this equation we get the following&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FCOfE.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FCOfE.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(the vertical axis is logarithmic)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can see that around 10 km away from the subsolar point, ~10 meters are enough to be closer than it to the Sun. ~30 meters at 20 km, ~800 meters at 100 km, ~3,000 m at 200 km, and if you go further than 340 km, not even Mount Everest will get you closer to the Sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, &lt;strong&gt;the closest point to the Sun will be whatever geographical feature that maximizes the value &lt;span class=&quot;math-container&quot;&gt;$\text{Altitude}-\Delta H$&lt;/span&gt;&lt;/strong&gt;, where &lt;span class=&quot;math-container&quot;&gt;$\text{Altitude}$&lt;/span&gt; is the altitude of the geographical feature. Let's call that point “&lt;em&gt;proxisolar&lt;/em&gt;” point. I just made up that name, but it will be handy for the following discussion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now that we understand the basis to establish what is the closest point to the Sun at a given moment, we can tackle the question that probably most people meant when asking this question:&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;What is the point on Earth that gets closest to the Sun over a year?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The most important fact to keep in mind, is that the variations of the distance between the Earth and the Sun over the year dwarf any topographical feature and even the diameter of the Earth itself. Earth’s distance from the Sun (center-to-center) varies from 147,098,074 km at perihelion (closest) to 152,097,701 km at aphelion (most distant). Therefore, the difference is &lt;strong&gt;5 million kilometers!&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The perihelion happens around January 4th, when the solar declination is about -23°, therefore, the latitude of the subsolar point is around 23° South. That rules out Chimborazo, Cayambe and Everest, because they are too far to be the “proxisolar” point. In contrast, &lt;a href=&quot;https://en.wikipedia.org/wiki/Sairecabur&quot; rel=&quot;noreferrer&quot;&gt;Sairecabur&lt;/a&gt; (5,971 m at 22.72° S) and &lt;a href=&quot;https://en.wikipedia.org/wiki/Licancabur&quot; rel=&quot;noreferrer&quot;&gt;Licancabur&lt;/a&gt; (5,916m at 22.83° S) are reasonable contestants.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem is that the perihelion happens on different days of the year and at different times of the day every year, so the point that gets closest to the Sun on a given year is just the one that happen to be the “proxisolar point” at the time of the Perihelion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;People who argues that Sairecabur or Licancabur are the points that get closer to the Sun, are implicitly assuming that the distance Earth-Sun doesn't vary much during the day of the perihelion. Therefore, the extra elevation of these mountains allows them to get closer to the Sun during that day. Unfortunately, that assumption is completely wrong. Let's see why:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An approximation of the distance Earth-Sun can be obtained from the following formula&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$d = \frac{a(1-e^2)}{1+e \cos\left(\text{days}\frac{360}{365.25}\right)}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where &lt;span class=&quot;math-container&quot;&gt;$a$&lt;/span&gt; is the semi-major axis of Earth's orbit, &lt;span class=&quot;math-container&quot;&gt;$e$&lt;/span&gt; is the eccentricity, and &lt;span class=&quot;math-container&quot;&gt;$\text{days}$&lt;/span&gt; is the number of days elapsed since the perihelion. To see the simplifications behind this equation &lt;a href=&quot;http://curious.astro.cornell.edu/about-us/41-our-solar-system/the-earth/orbit/80-how-can-i-find-the-distance-to-the-sun-on-any-given-day-advanced&quot; rel=&quot;noreferrer&quot;&gt;look here&lt;/a&gt; (note that the conversion factor 360/365.25 is erroneously inverted in that link, thanks @PM2Ring for spotting that).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you solve the above equation for the perihelion and for one day before/after it, you will get that the difference is 358 km, and for half a day you get 89 km. Therefore, if the subsolar point happens to be on the opposite side of the Earth than, let's say, Licancabur volcano, this volcano would need to be &lt;strong&gt;89 km higher that the subsolar point&lt;/strong&gt; to get closer than it to the Sun that year. 89 kilometers!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, &lt;strong&gt;we can discard the idea that a given mountain could be the point that gets closer to the Sun on EVERY year&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we plot the above equation with distances relative to the perihelion we get the following (using &lt;span class=&quot;math-container&quot;&gt;$a$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$e$&lt;/span&gt; from &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_orbit&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qShAo.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qShAo.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here we can see, that if the perihelion happens a bit more than 3 hours before or after the solar noon at Licancabur, the ~6,000 m of elevation advantage would not be enough to get closer to the Sun than the subsolar point at the perihelion, even if such point is at sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that three hours corresponds to 45° in Longitude, which at that approximate latitude corresponds to approximately 4,600 km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, it can be argued that Licancabur is the point on Earth that has more chances to be the closest to the Sun in an arbitrary year. But in a given year, it might or might not be the closest depending on where the subsolar point is at the moment of the perihelion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, it is important to note that the distance Earth-Sun at the perihelion varies widely from year to year. If you look at &lt;a href=&quot;http://www.astropixels.com/ephemeris/perap2001.html&quot; rel=&quot;noreferrer&quot;&gt;this table of perihelions between years 2001 and 2100&lt;/a&gt;, you will see that &lt;strong&gt;perihelions often vary by several thousand of kilometers&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, for example between years 2001 and 2100, the closest perihelion by far is the perihelion of next year (2020), and it will happen when the subsolar point is in the middle of the Indian ocean, about 12,700 km away from Licancabur and Sairecabur volcanoes. Therefore, the point that will be closest to the Sun this century will be one in the middle of the Indian ocean about 320 km south of &lt;a href=&quot;https://en.wikipedia.org/wiki/Rodrigues&quot; rel=&quot;noreferrer&quot;&gt;Rodrigues Island&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Said this, the question of which point on Earth will get closest to the Sun depends on the period of time on which it is considered. For each year, each century and any other arbitrary period of time, the answer will be different.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="14958" LastEditDate="2019-01-25T20:27:19.510" LastActivityDate="2019-01-25T20:27:19.510" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="16003" PostTypeId="2" ParentId="15971" CreationDate="2019-01-21T21:49:51.350" Score="3" Body="&lt;p&gt;A way to check if those clouds and precipitation are real is to check the same area and time with another radar.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.theweatherchaser.com/radar-loop/IDR713-sydney-terrey-hills/2019-01-17-06/2019-01-17-09&quot; rel=&quot;nofollow noreferrer&quot;&gt;This is the image loop of Sidney (Terrey Hills) radar for the same time&lt;/a&gt; (the same you used). It shows the same pattern than your image. In the animated images that arch centered in the radar looks even weirder.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.theweatherchaser.com/radar-loop/IDR043-newcastle/2019-01-17-07/2019-01-17-09&quot; rel=&quot;nofollow noreferrer&quot;&gt;This is the image loop of Newcastle radar for January 17th&lt;/a&gt;, which in great part overlaps the Terrey Hills radar image. It shows an arched pattern, too, and with similar radius, but this one is centered in Terrey Hills radar instead of the Newcastle radar.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, since those patterns are different for each radar, I would say that they are artefacts, and that both radars suffered from the same kind of artefacts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Interestingly, that kind of artifact seems consistent with the situation explained in dplmmr's comment: if both radar were just scanning an individual elevation angle (the same angle for both radars) and precipitation were just in a range of heights, we could expect that kind of pattern.&lt;/p&gt;&#xA;" OwnerUserId="6550" LastEditorUserId="6550" LastEditDate="2019-01-22T09:44:39.947" LastActivityDate="2019-01-22T09:44:39.947" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16004" PostTypeId="2" ParentId="16000" CreationDate="2019-01-22T01:07:37.880" Score="4" Body="&lt;p&gt;The point on the surface of the Earth where the Sun is currently immediately overhead is called the Zenith Point. Its Latitude and Longitude correspond to the Declination and Greenwich Hour Angle of the Sun. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These data points can be approximated to any degree of accuracy and timeframe by a Fourier series of n terms.  Accuracy sufficient for sextant work for the current decade can be achieved with a Fourier series of 7 terms). These terms are published in nautical almanacs.&lt;/p&gt;&#xA;" OwnerUserId="14844" LastActivityDate="2019-01-22T01:07:37.880" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16006" PostTypeId="2" ParentId="16000" CreationDate="2019-01-22T02:03:29.110" Score="10" Body="&lt;p&gt;It is impossible to know. Solar flares can have more than 500,000 kilometers. So if we consider them part of the sun, the moment when the earth is closer to the sun can be very different from perihelion if a big flare happens, making much of what was discussed in other answers irrelevant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lY1yd.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lY1yd.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14845" LastActivityDate="2019-01-22T02:03:29.110" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16011" PostTypeId="2" ParentId="16000" CreationDate="2019-01-22T20:13:19.290" Score="2" Body="&lt;p&gt;Whichever spot on the surface of the Earth is experiencing &lt;a href=&quot;https://en.wikipedia.org/wiki/Lahaina_Noon&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lahaina Noon&lt;/a&gt;, or would be if it wasn't cloudy, is at the &lt;a href=&quot;https://en.wikipedia.org/wiki/Subsolar_point&quot; rel=&quot;nofollow noreferrer&quot;&gt;subsolar point&lt;/a&gt; and pointed directly at the Sun, moreso than any other point on Earth at that moment.  Of course, you could get closer to the sun by climbing higher.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you were able to be &lt;strong&gt;at the summit of Chimborazo volcano in Ecuador (point furthest from the center of Earth) at Lahaina Noon at perihelion&lt;/strong&gt;, that would be as close to the Sun as you can get and still be on the surface of the Earth.   You'd probably have to be very lucky or &lt;em&gt;extremely&lt;/em&gt; patient for that to happen, though.&lt;/p&gt;&#xA;" OwnerUserId="3244" LastActivityDate="2019-01-22T20:13:19.290" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16013" PostTypeId="2" ParentId="14809" CreationDate="2019-01-23T03:02:51.657" Score="-1" Body="&lt;p&gt;I agree that this problem is very counterintuitive! However, the answer is very simple: &lt;strong&gt;the horizon is curved&lt;/strong&gt; (it is actually a circle that passes behind us as well as in front of us).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although it is curved, we generally perceive it as straight unless we specifically look for the curvature. This &quot;correction&quot; in our brains is what makes the angles seem wrong. You can see the curvature of the Earth anywhere there is a wide angle of open water (greater than 90 degrees is best) reaching the horizon. If you were standing on the moon and the moon's surface was smooth instead of mountainous, the curvature would be more apparent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The apparent direction the lit side of the moon is facing will always be higher than the apparent position of the sun due to the convex nature of the horizon. The greater the angular distance between the sun and the moon, the greater the effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another optical illusion explained the same way is that the apparent angles make it seem that the sun is as close as, or closer than the moon in your photo since the moon is at least half illuminated by the sun.&lt;/p&gt;&#xA;" OwnerUserId="5417" LastActivityDate="2019-01-23T03:02:51.657" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16016" PostTypeId="2" ParentId="15874" CreationDate="2019-01-23T10:56:31.480" Score="2" Body="&lt;p&gt;TrevorJ. Smith's answer sums it up nicely. SAWS data is certainly the only measured data you are likely to get and it is always preferable to use measured data over modelled data. If you request data from SAWS you will be asked to fill out and sign a disclosure statement, which will be evaluated. If they are satisfied with your request you will receive that data which provides rainfall data for every day within an available period (for a requested weather station). You can request through a &lt;a href=&quot;http://www.weathersa.co.za/compliments-complaints/climate-data-requests&quot; rel=&quot;nofollow noreferrer&quot;&gt;SAWS Data Request Form&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If your request is unsuccessful or you are happy to use modelled data I can recommend using CHIRPS data - see this &lt;a href=&quot;http://chg.geog.ucsb.edu/data/chirps/&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt; or you can view this dataset on &lt;a href=&quot;https://developers.google.com/earth-engine/datasets/catalog/UCSB-CHG_CHIRPS_DAILY&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google Earth Engine&lt;/a&gt;. Unfortunately CHIRPS data is only available from 1981.&lt;/p&gt;&#xA;" OwnerUserId="14900" LastActivityDate="2019-01-23T10:56:31.480" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16017" PostTypeId="2" ParentId="9482" CreationDate="2019-01-23T11:12:47.983" Score="9" Body="&lt;p&gt;I suspect you are referring to the mesas and buttes dotted around the Karoo - the large semi-arid plateau that makes up much of South Africa's interior. These are a product of the glacial and geological history of the region. The flat hills are capped by hard, resistant dolerite. This is solidified lava that was forced between the horizontal strata of the sedimentary rocks (which make up most of the Karoos geology) through high pressure. The dolerite erodes much slower than the surrounding rock and forms a flat cap above the underlying rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most South African mountains are actually not like this - Google &quot;Drakensberg&quot; and you will see that the country's most prominent and highest mountain range is far from flat and short!&lt;/p&gt;&#xA;" OwnerUserId="14900" LastEditorUserId="39" LastEditDate="2019-01-24T14:13:13.133" LastActivityDate="2019-01-24T14:13:13.133" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16025" PostTypeId="2" ParentId="15862" CreationDate="2019-01-23T15:17:47.707" Score="2" Body="&lt;p&gt;Earthquakes associated with volcanism or volcanic rifting are typically small. They are caused by over-pressurized magma as it moves around and intrudes into brittle rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sometimes, e.g., in Hawaii, you get earthquakes due to the gravitational sliding (e.g., the M6.9 earthquake in 2018 beneath Kilauea) as new eruption causes the volcano to grow in size (adding mass) which in turn cause it to slide over the older volcanic rocks underneath. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't think there's an exact upper bound for such an event but it is unlikely to exceed ~7.5. Another thing to keep in mind is that rocks near active volcanoes tend to be relatively hotter which in theory should cause less shaking during the earthquake (due to lower stress drop).&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2019-01-29T16:51:53.020" LastActivityDate="2019-01-29T16:51:53.020" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16026" PostTypeId="1" AcceptedAnswerId="16030" CreationDate="2019-01-23T15:57:43.373" Score="1" ViewCount="116" Body="&lt;p&gt;A recent answer by Camilo Rada for &lt;a href=&quot;https://earthscience.stackexchange.com/questions/16000/what-place-on-earth-is-closest-to-the-sun&quot;&gt;&quot;&lt;em&gt;What place on Earth is closest to the Sun?&lt;/em&gt;&quot;&lt;/a&gt; inspires this question. He makes clear that significant changes in the wander of the earth through its orbit results in striking effects on how close the closest distance is between these two bodies.  In the same thread others point out the height of solar flares relative the the baseline surface of the boiling hydrogen ball are likely even larger effects.  It is intuitive to me that the distance to the main producer of heat on the Earth SHOULD be a much larger effect than concentration of a gas in our atmosphere.  Is this a reasonable intuition?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my questions has four parts:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Generally, do the big dog scientists modeling for climate change in the next 100 years take these apparently very large effects into account in their models and how big of an effect is this compared to CO2 ppm levels?  It would be nice to have an answer in some sort of statistical level of confidence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Another way to consider this is how big of an effect is this variable compared to the expected CAUSES of CO2 ppm levels: combustion on earth of various kinds, respiration and farting of living species, chemical processes, etc&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) Can the sun's energy level, solar flare activity be modeled and used to predict, in the absence of CO2 ppm level changes, the temperature on earth in the future 5 years.?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;4) As Mr. Rada points out in the referenced thread is this distance changed on such a limited &lt;em&gt;timeline&lt;/em&gt; as to make it NOT as relevant or a lot smaller effect than it first seems?&lt;/p&gt;&#xA;" OwnerUserId="14907" LastEditorUserId="14901" LastEditDate="2019-01-24T03:29:24.710" LastActivityDate="2019-01-24T03:29:24.710" Title="Is the effect of Earths position relative to sun large or small compared to CO2 level in climate change?" Tags="|climate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16030" PostTypeId="2" ParentId="16026" CreationDate="2019-01-23T23:33:19.293" Score="2" Body="&lt;p&gt;The changes Camilo Rada discusses repeat annually so they average out over longer timescales and have no effect on climate. The flares reach less than &lt;span class=&quot;math-container&quot;&gt;$1\%$&lt;/span&gt; of the distance to earth and they are a recurring effect so they also average out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Greenhouse gases have a cumulative effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Solar activity is included in the IPCC.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-01-23T23:33:19.293" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16031" PostTypeId="1" CreationDate="2019-01-24T00:37:28.513" Score="2" ViewCount="222" Body="&lt;p&gt;Apparently there is so much phosphorus in waste water streams that states are &lt;a href=&quot;http://archive.jsonline.com/news/statepolitics/walker-signs-bill-easing-phosphorous-rules-for-communities-b99254590z1-256396661.html/&quot; rel=&quot;nofollow noreferrer&quot;&gt;passing laws to exempt water treatment facilities from having to spend billions removing the phosphorus&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't get this. I thought that phosphates had been banned in detergents and fertilizer years ago, so where is the phosphorus coming from?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2019-01-24T08:39:37.580" Title="How is phosphorus getting into lakes and rivers?" Tags="|water|pollution|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16033" PostTypeId="2" ParentId="13553" CreationDate="2019-01-24T07:35:25.070" Score="2" Body="&lt;p&gt;Recent literature points to an attempt to understand the theoretical dynamics behind the MJO as seen in these two publications - &lt;a href=&quot;https://link.springer.com/article/10.1007/s00382-018-4433-7#Equ2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dynamics moisture mode vs. moisture mode in MJO dynamics&lt;/a&gt; and &lt;a href=&quot;https://link.springer.com/article/10.1007%2Fs00382-016-3448-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;A general theoretical framework for understanding essential dynamics of Madden–Julian oscillation&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As concluded in the original paper by &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/1520-0493%281994%29122%3C0814%3AOOTDTO%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Madden and Julien oscillation&lt;/a&gt; the key is to observe that original MJ observations were either in a in phase relationship of the surface pressure and the zonal wind(850 hPa) or out of phase relationship. No such relationship was observed with the meridional wind.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the &quot;geostrophic balance&quot; in the MJO(in it's non dimensional form) is simply this equation&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$  \beta * y*u = -(\frac{\partial \Phi}{\partial y}) $$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So &lt;span class=&quot;math-container&quot;&gt;$\Phi$&lt;/span&gt; here represents the first baroclinic mode (the meaning of baroclinicity in the tropics is quite different to it's meaning in the mid latitudes). In the tropics what it means is that vertical structures of winds and currents that reverse directions (cf. &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2004RG000158&quot; rel=&quot;nofollow noreferrer&quot;&gt;MJO review&lt;/a&gt;). So the MJO has a baroclinic mode of vibration because the winds reverse direction from 850 hPa to 200 hPa. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in the assumption (proven by observations) that the  MJO can be characterized as a low frequency wave with an anisotropic horizontal length scale where the zonal length scale is much larger than the meridional scale by a magnitude of 10.So the meridional acceleration in the v-momentum equations can be neglected. With this approximation the zonal wind is in approximate geostrophic balance with the meridional pressure gradient  and all high frequency inertio gravity waves, mixed Rossby-gravity waves as well as short Rossby waves are all filtered out. So that only leaves the moist Kelvin and long Rossby waves as well as the MJO. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alternatively if one were to consider the &lt;a href=&quot;https://en.wikipedia.org/wiki/Rossby_radius_of_deformation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rossby radius of deformation&lt;/a&gt; in the case of the MJO the horizontal wavelength of the disturbance if equal to the Rossby radius of deformation then both the velocity and mass fields undergo mutual adjustment as illustrated in these slides - &lt;a href=&quot;https://www.ess.uci.edu/~yu/class/ess228/lecture.5.waves.2017.all.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Waves in Atmosphere &lt;/a&gt; on page 52. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similar conclusions were arrived at to derive balanced dynamics in the tropics by assuming linear theory and a shallow water model - &lt;a href=&quot;http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.582.8616&amp;amp;rep=rep1&amp;amp;type=pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Balanced dynamics in the tropics&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE&lt;/strong&gt;&#xA;Looking at other peer reviewed references that attempt to provide an explanation of the MJO it appears that an assumption of linear theory wrt to the MJO is not universally accepted and that non linear advection does have a role to play in the slowly propagating planetary scale disturbance(cf.&lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/1520-0469%281988%29045%3C0569%3AASMOTD%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Simple model of the 40-50 oscillation&lt;/a&gt;. A later paper by Madden(cf.&lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/1520-0469%281986%29043%3C3138%3ASVOTDO%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seasonal variations of the 40-50 oscillations in the tropics&lt;/a&gt; reports that  there can be substantial meridional wind perturbations bringing into question whether the assumption of geoostrophic balance is universally valid or not in the case of the MJO. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The original paper by MJ in the light of the observations obtained then perhaps made a conclusion that the structure and dynamics of the signal could resemble a Kelvin wave in which case the geostrophic balance of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Kelvin_wave&quot; rel=&quot;nofollow noreferrer&quot;&gt;Equatorial Kelvin wave&lt;/a&gt; (no large scale meridional wind perturbations and the equator acts as a wave guide ) could be used to explain the geostrophic balance in the case of the MJO. Later observations have proved this assumption incomplete. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-01-25T15:47:18.033" LastActivityDate="2019-01-25T15:47:18.033" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16034" PostTypeId="2" ParentId="16031" CreationDate="2019-01-24T08:39:37.580" Score="3" Body="&lt;p&gt;Phosphorus &amp;amp; phosphates are a key component of agricultural and garden &lt;a href=&quot;https://en.wikipedia.org/wiki/Fertilizer#Phosphates&quot; rel=&quot;nofollow noreferrer&quot;&gt;fertilizers&lt;/a&gt;. Most plants need nitrogen (N), phosphorus (P) and potassium (K). They are generally combined into one product called NPK fertilizers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nitrogen is needed for leaf growth. Phosphorus is needed for roots, flowers, seeds and fruit and potassium is needed for stem growth and water movement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The trouble with the use of fertilizers is they get dumped onto plants periodically and the plants cannot use all of the elements in the fertilizer at that time. What isn't absorbed by plants eventually is leached from soil via rain or irrigation water and it ends up in rivers, streams and sometimes lakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Australia, phosphorus can  be toxic to some &lt;em&gt;native plants&lt;/em&gt; because over millennia Australia's, so called, soil, have been depleted of phosphorus and plants evolved to live with either no or very little phosphorus,&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-01-24T08:39:37.580" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16036" PostTypeId="1" CreationDate="2019-01-24T11:34:55.777" Score="3" ViewCount="66" Body="&lt;p&gt;If I calculate daily accumulated precipitation or daily maximum temperature from global climate data, will I be getting statistics over different local times, because the operation uses the climate model time which is UTC?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So for example, on day N I will get the maximum temperature from &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;midnight to 11:59pm in London, Dhaka, Portugal (UTC 0)&lt;/li&gt;&#xA;&lt;li&gt;10am on day N to 9:59am on day N+1 in eastern Australia (UTC+10)&lt;/li&gt;&#xA;&lt;li&gt;5pm on day N-1 to 4:59pm on day N in western US and Canada (UTC-7)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="14922" LastEditorUserId="14922" LastEditDate="2019-01-24T11:45:34.530" LastActivityDate="2019-01-24T14:04:41.260" Title="Do daily operations (max, min etc) on climate model data reference different periods because of UTC?" Tags="|climate|temperature|rainfall|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16037" PostTypeId="2" ParentId="16036" CreationDate="2019-01-24T14:04:41.260" Score="1" Body="&lt;p&gt;Yes, your understanding is correct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(this is a really short answer because I can't think what else to say!)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm no expert on this type of simulation, but I suspect that any application where you care whether something happens in day 158 or day 159 is probably not an application that you want to be using a global climate model for... &lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-01-24T14:04:41.260" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16038" PostTypeId="1" AcceptedAnswerId="16041" CreationDate="2019-01-24T14:20:45.637" Score="6" ViewCount="375" Body="&lt;p&gt;Due to global warming and Arctic amplification, Northern Hemispheric permafrost is thawing and becoming a source of carbon and many greenhouse gases, which then positively feedback to global warming again.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More specifically, severe &lt;strong&gt;Arctic coastal erosion&lt;/strong&gt; of permafrost material has taken place in recent years. How relevant is this specific process, alone, to Earth's climate in general, or at least to the Arctic climate?&lt;/p&gt;&#xA;" OwnerUserId="8396" LastEditorUserId="11908" LastEditDate="2019-01-24T19:32:50.860" LastActivityDate="2019-04-19T03:24:48.620" Title="What is the relevance of Arctic coastal erosion to the Earth's climate?" Tags="|climate-change|carbon-cycle|arctic|cryosphere|permafrost|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16040" PostTypeId="1" AcceptedAnswerId="16048" CreationDate="2019-01-24T19:21:03.810" Score="4" ViewCount="1946" Body="&lt;p&gt;I'm studying Plutonic (Intrusive) rocks and I really don't understand the difference between Plutonic Rocks that form in Sills and Dikes from the so called  subvolcanic rocks, also known as a hypabyssal rocks. Aren't they the same? Why?&lt;/p&gt;&#xA;" OwnerUserId="12836" LastEditorUserId="2958" LastEditDate="2019-06-24T08:25:23.187" LastActivityDate="2019-06-24T08:25:23.187" Title="What is the difference between subvolcanic rocks and plutonic rocks?" Tags="|geology|rocks|magmatism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16041" PostTypeId="2" ParentId="16038" CreationDate="2019-01-24T19:21:50.297" Score="6" Body="&lt;p&gt;If we consider only the climatic impacts of Arctic coastal erosion, there are still two sides of the question of how relevant is Arctic coastal erosion of permafrost.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first side is how big is its current role as a &lt;span class=&quot;math-container&quot;&gt;${CO}_2$&lt;/span&gt; source, and the second is how much of risk it posses for future climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It term of current contribution the answers is that it is not very relevant. According to the &quot;&lt;a href=&quot;https://link.springer.com/article/10.1007/s12237-010-9362-6&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Arctic Coastal Dynamics Database: A New Classification&#xA;Scheme and Statistics on Arctic Permafrost Coastlines&lt;/a&gt;&quot; from 2011, there are 101,447 km of coastline in the Artic, and the mean coastal erosion rate is 0.5 m/yr with a mean backshore elevation of 8.3 m. Multiplying all those numbers we get that 421,005,050 &lt;span class=&quot;math-container&quot;&gt;$\text{m}^3$&lt;/span&gt; of Arctic soil are lost to the sea every year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That paper is behind a paywall so I'll copy here Table 2 (where most of above numbers come from) and figure 6 that are relevant here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YVkhm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YVkhm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MzzLT.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MzzLT.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Table 2 also indicates that ~2% of the weight of that lost soil corresponds to carbon, so using a bulk density of 1,900 &lt;span class=&quot;math-container&quot;&gt;$\text{kg}/\text{m}^3$&lt;/span&gt; (&lt;a href=&quot;https://www.earth-syst-sci-data.net/10/355/2018/essd-10-355-2018.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;) you get that the lost corresponds to 0.00002 Pg C (peta grams of carbon) per year, a very small number compared with the ~&lt;a href=&quot;https://www.researchgate.net/publication/311760100_Perspectives_on_the_Terrestrial_Organic_Matter_Transport_and_Burial_along_the_Land-Deep_Sea_Continuum_Caveats_in_Our_Understanding_of_Biogeochemical_Processes_and_Future_Needs/figures?lo=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;7.8 Pg C that burning fossil fuels put into the atmosphere every year&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, it is more concerning the potential of permafrost lost. Scientist have studied Arctic ocean sediments and found that during the period of fast sea level rise at the end of the last ice age, a huge amount of organic carbon stored in permafrost was released (&lt;a href=&quot;https://www.nature.com/articles/s41467-018-06080-w&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;), perhaps close to 1,000 Pg (&lt;a href=&quot;https://www.nature.com/articles/ncomms13653#ref1&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;). Carbon that was then available for microorganism to metabolize and transform into greenhouse gases as carbon dioxide and methane. This greenhouse gases helped warming the Earth and melting the ice caps that covered it at that time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are still about 1,300 Pg of carbon stored in permafrost (&lt;a href=&quot;https://www.nature.com/articles/ncomms13653#ref1&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;). Thawing of permafrost is increasing rapidly. As well as coastal erosion rates. In coastal Alaska for example it have increased from 6.8 m/yr in 1955-1979, to 8.7 m/y in 1979-2002, to 13.6 m/yr on 2002-2007 (&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2008GL036205&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;).&#xA;Arctic warming, sea level rise and release of permafrost organic carbon form part of a dangerous positive feedback cycle that we don't know how far or how fast it can go. And it have the potential to release massive, and this time, VERY considerable quantities of greenhouse gases into the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-01-26T18:18:57.410" LastActivityDate="2019-01-26T18:18:57.410" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16042" PostTypeId="2" ParentId="15874" CreationDate="2019-01-24T21:51:50.303" Score="1" Body="&lt;p&gt;The &lt;a href=&quot;https://climexp.knmi.nl/start.cgi&quot; rel=&quot;nofollow noreferrer&quot;&gt;KNMI Climate Explorer&lt;/a&gt; is a great resource both for modelled data and actual station measurements. Monthly station data can be searched &lt;a href=&quot;https://climexp.knmi.nl/selectstation.cgi?id=d17099be003bf17970040ea12c50ad61&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They have data from several stations in South Africa, I pulled out this time series of precipitation for Cape Town&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cLIrZ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cLIrZ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can find more info or download the date in the &lt;a href=&quot;https://climexp.knmi.nl/getprcpall.cgi?id=d17099be003bf17970040ea12c50ad61&amp;amp;WMO=68816&amp;amp;STATION=CAPE_TOWN_D.F._MALAN&amp;amp;extraargs=&quot; rel=&quot;nofollow noreferrer&quot;&gt;page for this station&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-01-24T21:51:50.303" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16043" PostTypeId="2" ParentId="14915" CreationDate="2019-01-24T22:25:49.927" Score="2" Body="&lt;p&gt;Dr. &lt;a href=&quot;http://www-spc.igpp.ucla.edu/~strange/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Robert Strangeway&lt;/a&gt; kindly shared with me the poster he presented at AGU fall meeting 2017, the one I cited in the question based in the abstract only. I've included below some of the key parts of the poster with some text highlight added by me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;He focus on Oxygen loss as a proxy of water loss. And the answer to my question that can be derived from this work I think would be:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Currently Earth intrinsic magnetic field doesn't seem to be more efficient in preventing Oxygen loss than the induced magnetic fields of Venus and Mars. However, while is relatively easy to model the effects of intrinsic magnetic fields in the past of Venus and Mars (when solar wind was stronger), we do not have the knowledge to do such modeling for the case of the Earth's intrinsic magnetic field. Therefore, we don't know if such intrinsic magnetic field was or not an advantage in the past.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/abHvd.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/abHvd.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NilTG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NilTG.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YG0km.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YG0km.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZzkJb.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZzkJb.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kpPep.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kpPep.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-01-24T22:25:49.927" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16045" PostTypeId="1" AcceptedAnswerId="16052" CreationDate="2019-01-25T11:48:12.790" Score="5" ViewCount="223" Body="&lt;p&gt;A big argument for carbon capture and storage is true reversal; while switching to renewable energy and eliminating CO&lt;sub&gt;2&lt;/sub&gt; emissions is a must, it will not reverse the massive movement of carbon from underground hydrocarbons to the atmosphere and biosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, prevailing strategies are not exact reversals of burning fuels, either. Rather than converting CO&lt;sub&gt;2&lt;/sub&gt; to hydrocarbons to be buried, CO&lt;sub&gt;2&lt;/sub&gt; may be directly injected deep into the ground or converted to carbonates first. Would there be consequences for the biosphere if we do manage to bury 2-3 oxygen atoms for every carbon atom that will also be buried, that so far would have been released into the atmosphere?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: For the sake of argument, let's assume a hypothetical method of capture and storage that uses only renewable energy and that the buried matter does not leak back out. This question should not be construed as an endorsement of current carbon capture and storage technology.&lt;/p&gt;&#xA;" OwnerUserId="14951" LastEditorUserId="725" LastEditDate="2019-01-26T00:13:42.953" LastActivityDate="2019-01-26T00:13:42.953" Title="Are there any consequences to carbon capture and storage that also sequesters oxygen?" Tags="|atmosphere|climate-change|carbon-cycle|carbon|oxygen|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16048" PostTypeId="2" ParentId="16040" CreationDate="2019-01-25T19:11:16.357" Score="4" Body="&lt;p&gt;Main difference between a subvolcanic verses a  plutonic is depth at which the rock solidified at from its molten state.  Plutonic implies a depth greater than subvolcanic by definition but I am sure there is some overlap between shallow end of plutonic and subvolcanic.  Depth of emplacement for plutonic would mostly be much greater than 2 km.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.azomining.com/Article.aspx?ArticleID=1287&quot; rel=&quot;nofollow noreferrer&quot;&gt;Plutonic&lt;/a&gt; is an igneous rock formed by solidification at considerable depth beneath the earth's surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Subvolcanic rock, also known as a hypabyssal rock, is an intrusive igneous rock that is emplaced at medium to shallow depths (&amp;lt;2 km) within the crust.  &lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="1149" LastEditDate="2019-01-26T16:55:00.260" LastActivityDate="2019-01-26T16:55:00.260" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16050" PostTypeId="2" ParentId="15989" CreationDate="2019-01-25T19:25:10.753" Score="3" Body="&lt;p&gt;It can be hard to distinguish man-made smoky quartz from natural smoky quartz. Traditional methods for irradiation to convert quartz to smoky quartz tends to leave the quartz crystals looking more black than translucent smoky brown.  This is caused in part by the rapid irradiation time for man-made smoky quartz.  I am sure a more patient man-made process could produce more naturally smoky quartz.&lt;/p&gt;&#xA;&lt;p&gt;The best way to determine if smoky quartz is man-made or not is to know the location for the quartz specimen.  Arkansas, USA produces mostly clear quartz and very little natural smoky quartz.  Dark smoky quartz from Arkansas is almost certainly artificially made.  I have a specimen of dark smoky quartz which is almost black from Bear Lodge mountain, Wyoming that is definitely natural.&lt;/p&gt;&#xA;&lt;p&gt;Best practice, if a smoky quartz specimen does not have a well known location, assume its man-made – never pay a lot for it.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="534" LastEditDate="2022-10-29T22:04:11.790" LastActivityDate="2022-10-29T22:04:11.790" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16052" PostTypeId="2" ParentId="16045" CreationDate="2019-01-25T21:24:24.553" Score="1" Body="&lt;p&gt;No, I think there are not. At least not at the scale of the proposed projects. I say this just because &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; makes up &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;only a 0.04%&lt;/a&gt; of the atmosphere, so even if you burn fossil fuels until you double the pre-industrial amount of CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; and then capture and bury it back (both the Carbon and Oxygen). You would only drop Oxygen levels from its current 20.95% to 20.91% or something like that, which is not very significant. In a closed space like your bedroom for instance, you would probably make a bigger change in the Oxygen level by just breathing inside for a few minutes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, many chemical reactions that sequester Oxygen and are sensitive to its concentration (oxidation and combustion for example) would work towards keeping equilibrium: they will slow down if there is less Oxygen allowing the concentration to bounce back. Or they will accelerate if there is too much Oxygen, dropping the level back down.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-01-25T21:46:58.880" LastActivityDate="2019-01-25T21:46:58.880" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16053" PostTypeId="1" AcceptedAnswerId="16057" CreationDate="2019-01-25T21:31:14.943" Score="5" ViewCount="1069" Body="&lt;p&gt;Some arguments I've seen about the viability of silicon-based life involve the relative abundance of silicon vs carbon. In the universe as a whole, there's a lot more carbon than silicon around. Yet, on Earth, silicon is far more common. So how did this happen? &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7760/why-silicon-is-abundant-in-earth-surface&quot;&gt;This question&lt;/a&gt; partially answers why there seems to be a lot of silicon in the Earth's crust, but it doesn't explain where all the carbon went.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So where did it go?&lt;/p&gt;&#xA;" OwnerUserId="14962" LastActivityDate="2019-01-26T00:10:03.873" Title="Why is there so much more silicon than carbon in the Earth's crust?" Tags="|crust|carbon|planetary-formation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16054" PostTypeId="1" CreationDate="2019-01-25T22:19:32.327" Score="3" ViewCount="132" Body="&lt;p&gt;I am familiar with the concept of harmonic tide coefficients and was wondering about the simplest software solution to calculate tides anywhere, worldwide. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any available, open source packages to achieve this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks,&#xA;EL&lt;/p&gt;&#xA;" OwnerUserId="14963" LastActivityDate="2019-01-25T22:37:16.153" Title="Global tide calculation" Tags="|oceanography|tides|ocean-models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16056" PostTypeId="2" ParentId="16054" CreationDate="2019-01-25T22:37:16.153" Score="2" Body="&lt;p&gt;Science-quality tools for global and regional tidal heights and transports are available at &#xA;&lt;a href=&quot;http://volkov.oce.orst.edu/tides/global.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://volkov.oce.orst.edu/tides/global.html&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="11269" LastActivityDate="2019-01-25T22:37:16.153" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16057" PostTypeId="2" ParentId="16053" CreationDate="2019-01-26T00:10:03.873" Score="8" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;So where did it go?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Carbon was never there (or here) to begin with. You need to look at this from the opposite way. By asking &quot;where did it go&quot; you assuming the Earth was here first, with carbon, and then the carbon was removed somehow. But, Earth formed from a gaseous solar nebula that had all the elements.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the Earth-forming materials started condensing, they consisted primarily of the refractory elements (i.e., elements that form compounds with high melting and boiling points). The volatile elements (i.e., elements that form compounds that you would mostly recognise as gas or liquid).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These volatile elements never accreted to Earth in any significant amounts. They &quot;boiled&quot; away. They were removed by the solar wind farther away. Carbon was mostly in CO, CH&lt;sub&gt;4&lt;/sub&gt;, CO&lt;sub&gt;2&lt;/sub&gt;, etc. These are volatile compounds that never accreted to the Earth, and by the time Earth was large enough to have a gravity to sustain a proper atmosphere, the carbon was all gone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's not only carbon. Neon is one of the most abundant elements in the solar system, but there's almost none on Earth. Nitrogen - we only have it in the atmosphere, which is a negligible component of Earth's total mass. Same with hydrogen. Just a small crust of ocean on the surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's why Earth is made of Si, Al, Mg, Fe and Ca oxides. Oxygen bonded to those elements makes very refractory solid minerals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further reading&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Frost_line_(astrophysics)&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Frost_line_(astrophysics)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements#Earth&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elements#Earth&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-01-26T00:10:03.873" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16059" PostTypeId="1" CreationDate="2019-01-26T00:40:07.043" Score="3" ViewCount="312" Body="&lt;p&gt;I have seen things like this appear once or twice on cold winter mornings, a frozen spike of water from an ice-covered container or very small body of water (puddle).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found the photo below at &lt;a href=&quot;https://www.bbastrodesigns.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mel Bartels and BBAstroDesigns&#xA;&lt;/a&gt; and the caption reads:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;An ice spike in a bird bath following a cold snap December 2014&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What could be happening here? How might the two structures form like this, both tilted against gravity?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;update:&lt;/strong&gt; Comments indicate that Wikipedia's article &lt;a href=&quot;https://en.wikipedia.org/wiki/Ice_spike&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ice spike&lt;/a&gt; gives an explanation based on the growth of a tube as the freezing process extends from top-down into the liquid, pushing remaining liquid out a hole and growing vertically from a central opening in the tube.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I can't see how this makes a spike with such a large angle with respect to vertical. It really looks to my untrained eye like this is a frozen jet, but that's not so likely as water is not so compressible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VEohV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VEohV.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2019-08-28T21:00:53.730" LastActivityDate="2019-08-28T21:00:53.730" Title="What causes frozen &quot;shooting water&quot; spikes from ice covered water in the winter?" Tags="|meteorology|ice|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16060" PostTypeId="2" ParentId="9385" CreationDate="2019-01-26T02:53:09.227" Score="2" Body="&lt;p&gt;Based on an answer from ECMWF support which OP can confirm to my best understanding relative vorticity in the ECMWF model is not calculated using grid points and finite differences (centered and forward and backward). Instead it is calculated using  &lt;a href=&quot;https://earthscience.stackexchange.com/questions/12884/how-do-spectral-methods-work-in-the-context-of-numerical-weather-prediction-mode&quot;&gt;spectral approaches in meteorology&lt;/a&gt;. There is a package in Fortran called &lt;a href=&quot;https://www2.cisl.ucar.edu/resources/legacy/spherepack&quot; rel=&quot;nofollow noreferrer&quot;&gt;spherepack&lt;/a&gt; and a python wrapper as well &lt;a href=&quot;https://github.com/jswhit/pyspharm&quot; rel=&quot;nofollow noreferrer&quot;&gt;pyspharm&lt;/a&gt; that one can use to convert grid points to spectral approach but the data has to be global. Output of regional mesoscale models will not work. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if you are using data from a GCM that is using grid points I would suggest you convert to spectral approach first, calculate the vorticity(&lt;strong&gt;HINT :&lt;/strong&gt; use &lt;a href=&quot;https://ajdawson.github.io/windspharm/latest/&quot; rel=&quot;nofollow noreferrer&quot;&gt;windspharm&lt;/a&gt; for this purpose). As Jareth Holt mentions in the comments you will need to smoothen the relative vorticity and here is a link that shows you how to do that - &lt;a href=&quot;https://www.geosci-model-dev.net/7/1841/2014/gmd-7-1841-2014.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Smoothen Relative Vorticity&lt;/a&gt;. If values of absolute vorticity appear correct(and by that I mean by and large positive in NH and negative in SH)  then proceed to calculate the isentropic PV by interpolating from model levels to isentropic levels  using Newton Raphson interpolation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are going to stick with grid points and finite differences the formulae for relative vorticity must include &lt;strong&gt;map scale factors&lt;/strong&gt; assuming data is available as a function of latitude and longitude and you need some formula for calculating vorticity at the poles. Your code as it stands does not include &lt;strong&gt;map scale factors&lt;/strong&gt; in the relative vorticity calculation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are few other issues that you will need to take into consideration. When these isentropic surfaces intersect the earth's surface the values for temperature and surface pressure will need to be extrapolated. The necessary ECMWF documentation for that is available on a google search for the same. Finally all super adiabatic layers must be eliminated prior to isentropic interpolation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Instead of showing us the entire code please verify if the several &quot;little&quot; calculations that go into calculating PV(relative vorticity, absolute vorticity, calculation of static stability, isentropic interpolation)are correct and then the calculations sorts itself out.&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-01-26T08:05:19.113" LastActivityDate="2019-01-26T08:05:19.113" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16061" PostTypeId="2" ParentId="16000" CreationDate="2019-01-26T03:33:35.710" Score="1" Body="&lt;p&gt;At any one specific moment the subsolar point is the point on Earth that is closest to the Sun at that specific moment.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The subsolar point on a planet is the point at which its sun is perceived to be directly overhead (at the zenith);[1] that is, where the sun's rays strike the planet exactly perpendicular to its surface. It can also mean the point closest to the sun on an astronomical object, even though the sun might not be visible.&lt;/p&gt;&#xA;&lt;p&gt;To an observer on a planet with an orientation and rotation similar to those of Earth, the subsolar point will appear to move westward, completing one circuit around the globe each day, approximately moving along the equator. However, it will also move north and south between the tropics over the course of a year, so it is spiraling like a helix.&lt;/p&gt;&#xA;&lt;p&gt;The subsolar point contacts the Tropic of Cancer on the June solstice and the Tropic of Capricorn on the December solstice. The subsolar point crosses the Equator on the March and September equinoxes.&lt;/p&gt;&#xA;&lt;p&gt;When the point passes through Hawaii, the only U.S. state in which this happens, it is known as Lahaina Noon.[2]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;There is a minor exception to this rule.&lt;/p&gt;&#xA;&lt;p&gt;The subsolar point can be defined as a mathematical point, so that someone could theoretically be standing with their body over the exact mathematical subsolar point and with their two legs and feet on either side of the exact mathematical subsolar point.&lt;/p&gt;&#xA;&lt;p&gt;Thus a place that is close to the the exact mathematical subsolar point and at a higher altitude than it might be closer to the Sun than the exact mathematical subsolar point.  The farther away from the exact mathematical subsolar point a place is the higher its altitude must be in order to be closer to the Sun than the exact mathematical subsolar point.&lt;/p&gt;&#xA;&lt;p&gt;Earth has an polar radius of 6,356.8 kilometers and an equatorial radius of 6,378.1 kilometers, so a place at the equator is 21.3 kilometers farther from the center of the Earth than a place at one of the poles, not allowing for minor variations in the figure of the Earth and not allowing for altitude differences.&lt;/p&gt;&#xA;&lt;p&gt;The subsolar point of earth is never farther north than the Tropic of Cancer and never farther south than the Tropic of Captricorn, and so in recent times is never North of about 23 degrees 26 minutes North Latitude or south of about 23 degrees 26 minutes South Latitude.&lt;/p&gt;&#xA;&lt;p&gt;Of the points mentioned in the question Chimborazo and Cayambe Volcanoes in Ecuador, and Sairecabur and Licancabur Volcanoes in Chile, are within the tropics and thus can sometimes be the subsolar points, while Mount Everest is north of the Tropic of cancer and can never be the subsolar point.&lt;/p&gt;&#xA;&lt;p&gt;If Earth as a radius of 6,356.8 to 6,378.1 kilometers, it must have diameter of 12,713.6 to 12,756.2 kilometers, and thus at any one moment the subsolar point, wherever it is at that moment,  will be about 12,713.6 to 12,756.2 kilometers closer to the Sun than the point that is farthest from the Sun, wherever it is at that moment.&lt;/p&gt;&#xA;&lt;p&gt;The semi-major axis of the orbit of the Earth is 149,598,023 kilometers, which can be taken as the average distance between the Earth and the Sun. Whenever the Earth is exactly 149,598,023 kilometers, the subsolar point will be about 12,713.6 to 12,756.2 kilometers closer to the Sun than the point that is farthest from the Sun.&lt;/p&gt;&#xA;&lt;p&gt;So at any moment when Earth was exactly 149,598,023 kilometers from the Sun, and the subsolar point happens to be 12,756.2 kilometers closer to the Sun than the point on Earth farthest from the Sun, the difference will be 1 in 11,727.475, or 0.0000852 of the distance between the Earth and the Sun.&lt;/p&gt;&#xA;&lt;p&gt;The perihelion distance between Earth and the Sun is 147,095,000 kilometers while the aphelion distance between Earth and the Sun is 152,100,000 kilometers, a difference of 5,005,000 kilometers. Since it takes earth about half a year, or about 182.625 days, to go from Aphelion to perihelion, the distance between Earth and the Sun changes by an average of about 27,405.886 kilometers per day.&lt;/p&gt;&#xA;&lt;p&gt;Thus any point on Earth, even the point on Earth that is farthest from the Sun, at the exact moment of perihelion should still be closer to the Sun than any point on Earth, even the subsolar point, on any other day of the year.&lt;/p&gt;&#xA;&lt;p&gt;What about astronauts in orbit, bound by gravity to the Earth?  Do their capsules and space stations count?  Whether or not space capsules and space stations count as part of Earth, some astronaut in Earth orbit might have been closer to the Sun and another astronaut might in earth orbit have been farther from the Sun than any human in history.&lt;/p&gt;&#xA;&lt;p&gt;And what about Apollo astronauts who traveled to the Moon and orbited or passed beyond it?  Does the Moon count as a place on Earth since it is bound to Earth by gravity?  And even if not, some Apollo astronaut or astronauts must have been farther from Earth than any other humans.&lt;/p&gt;&#xA;&lt;p&gt;The Apollo missions all lasted for at least a quarter of a lunar orbit around the Earth.  The landings on the Moon were all on the near side of the Moon that faces the Earth, and all during the Lunar day, which means that the near side of the Moon must have been facing the Sun and thus farther from the Sun than Earth during the missions.&lt;/p&gt;&#xA;&lt;p&gt;Earth is at perihelion, closest to the Sun around January 4, and at aphelion, farthest from the Sun, around July 4.&lt;/p&gt;&#xA;&lt;p&gt;So of the manned missions that reached Lunar orbit, Apollo 11, July 1624, 1969, and Apollo 15, July 26-August 7, 1971, were closest to aphelion about July 4, and so their astronauts might have traveled farther from the Sun than any other humans, depending on where the Moon was during its orbit.&lt;/p&gt;&#xA;&lt;p&gt;And Apollo 8, December 21-27 1968, Apollo 17, December 7-19 1972, and Apollo 14, January 31-February 9, 1971, were closed to perihelion about January 4.  And so the astronauts in one of those missions might have come closest to the Sun of all humans.  But I doubt that.  Probably some astronaut(s) who orbited the Earth several times on a January 4 passed close to a point above the subsolar point at a time very close to perihelion and came closed to the Sun - or least far from it - of all humans so far.&lt;/p&gt;&#xA;" OwnerUserId="14967" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-01-26T03:33:35.710" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16065" PostTypeId="1" CreationDate="2019-01-26T15:46:41.430" Score="0" ViewCount="123" Body="&lt;p&gt;I want to test a program for image classification that uses GeoTiff data with a separate file for each band. So I'm looking for some sample satellite data, preferably of Landsat 7, that doesn't need any further correction or pre-processing (I'm not familiar with these things and just want to do a brief testing) and can be used as is. It should be in separate GeoTiff files for each band, or there should be a way to separate them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I already searched a lot in the web and found services like GloVis, LandsatLook Viewer or USGS Earth Explorer, but I simply don't know how to use this data, it seems to require pre-processing, which I have neither the skills for nor do I have the software for that.&lt;/p&gt;&#xA;" OwnerUserId="14690" LastActivityDate="2019-01-28T06:00:43.593" Title="Where can I download Landsat 7 data as GeoTiff" Tags="|open-data|satellites|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16066" PostTypeId="1" AcceptedAnswerId="16068" CreationDate="2019-01-26T19:34:40.793" Score="4" ViewCount="247" Body="&lt;p&gt;Were there any polar vortexes in 2018? On what dates? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to see what the weather looked like on those dates: &lt;a href=&quot;https://www.youtube.com/watch?v=FPuDPxK88g0&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=FPuDPxK88g0&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes I know. You would think that I could just google it and it would be the first thing on the page. But no. &lt;/p&gt;&#xA;" OwnerUserId="6615" LastActivityDate="2019-02-02T07:20:40.140" Title="Were there any polar vortexes in 2018?" Tags="|meteorology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16068" PostTypeId="2" ParentId="16066" CreationDate="2019-01-27T02:47:27.670" Score="15" Body="&lt;p&gt;First of all the question is not appropriately titled. The polar vortex &lt;em&gt;ALWAYS&lt;/em&gt; exists as explained in this URL - &lt;a href=&quot;https://www.weather.gov/safety/cold-polar-vortex&quot; rel=&quot;noreferrer&quot;&gt;What is the Polar Vortex ?&lt;/a&gt;. The real question is whether a polar vortex split up at the poles and the smaller vortices moved equatorward or not. In February of 2018 the polar vortex did split high up in the atmosphere due to a &lt;a href=&quot;https://en.wikipedia.org/wiki/Sudden_stratospheric_warming&quot; rel=&quot;noreferrer&quot;&gt;SSW event&lt;/a&gt;.  If we take a look at it from GFS forecast data from the period - &lt;a href=&quot;https://earth.nullschool.net/#2018/02/09/0000Z/wind/isobaric/10hPa/orthographic=-309.84,77.65,347/loc=-60.080,35.968&quot; rel=&quot;noreferrer&quot;&gt;February 2nd 2018 10 hPa wind data&lt;/a&gt; and then a few days later - &lt;a href=&quot;https://earth.nullschool.net/#2018/02/12/0000Z/wind/isobaric/10hPa/orthographic=-309.84,77.65,347&quot; rel=&quot;noreferrer&quot;&gt;February 12th 2018 10 hPa wind data&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/National_Observatory_of_Athens&quot; rel=&quot;noreferrer&quot;&gt;Content owned by The National Observatory of Athens, Greece&lt;/a&gt; confirms it in this youtube video - &lt;a href=&quot;https://www.youtube.com/watch?v=cvPgY3T0EdQ&quot; rel=&quot;noreferrer&quot;&gt;Polar Vortex split&lt;/a&gt;. An associate of mine who creates popular science videos for the larger public came up with a layperson's view of the polar vortex in this youtube video -&lt;a href=&quot;https://www.youtube.com/watch?v=Y1sw5qLpuSU&quot; rel=&quot;noreferrer&quot;&gt;SSW explanation plus polar vortex split&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The key point in Simon Clark's video of the sudden warming of the stratosphere can be seen in GFS forecast data as well - &lt;a href=&quot;https://earth.nullschool.net/#2018/02/09/0000Z/wind/isobaric/10hPa/overlay=temp/orthographic=-309.84,77.65,347/loc=30.846,75.106&quot; rel=&quot;noreferrer&quot;&gt;Air temperature before polar vortex split at 10 hPa&lt;/a&gt; and this &lt;a href=&quot;https://earth.nullschool.net/#2018/02/12/0000Z/wind/isobaric/10hPa/overlay=temp/orthographic=-309.84,77.65,347/loc=60.255,68.289&quot; rel=&quot;noreferrer&quot;&gt;Air temperature after the polar vortex split &lt;/a&gt;&#xA;There is a 40 degree centigrade warming of the stratospheric air at 10 hPa over some locations. Over the temporal scale (3-4 days) that is fairly dramatic and that effect is eventually &quot;felt&quot; at the surface level. While the mechanism behind this is still a matter of deep research the impact is synoptic to planetary scale to cause a  cold wave through Europe as was asked in this question - &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13501/where-did-the-daily-temperature-variation-go&quot;&gt;Where did the daily temperature variation go?&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally I am not sure of the impact on US stations but I believe it affected Western Canada and Europe. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE&lt;/strong&gt;&#xA;With NOAA partially restoring their database and their website the images are available now. I am displaying the 10 hPa air temperature for two different dates. One is before the SSW event (9th February 2018) and another one after the SSW event (13th February 2018). The stereographic projection is over the northern hemisphere &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PqqjT.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PqqjT.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/bgPfN.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bgPfN.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As one can make out over large areas of the North Pole the air temperature at the 10 hPa has increased by around 40-50 degree Kelvin and the colder air has been displaced equatorwards. Unlike the GFS forecast images shown earlier these temperature values are the mean values averaged over a single day and are therefore more representative than a single time associated with the GFS data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally the vector wind at the 10 hPa levels on both those two days and you can see clearly the split vortices in this one &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UF5zo.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UF5zo.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/O2KBJ.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/O2KBJ.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looking at the literature for the polar vortex splits it appears that they also use the geopotential height increase over the poles to indicate the impact of a SSW. &#xA;The first image is prior to  a SSW which indicates the presence of a stable polar vortex(lowered geopotential height)&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Q2Q9D.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Q2Q9D.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second image is after a SSW and one that indicates the instability of the polar vortex(it's weakened state) and split vortices over Western Canada and Northern Europe. (Geopotential height increase over the poles). &#xA;&lt;a href=&quot;https://i.stack.imgur.com/XT2q5.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XT2q5.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Copyright Owner for NCAR NOAA images&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.esrl.noaa.gov/psd/data/composites/day/&quot; rel=&quot;noreferrer&quot;&gt;NOAA NCAR URL&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-02-02T07:20:40.140" LastActivityDate="2019-02-02T07:20:40.140" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16070" PostTypeId="1" CreationDate="2019-01-27T08:58:19.170" Score="6" ViewCount="162" Body="&lt;p&gt;I have been to different places with nearly the same freezing temperatures, around -2°C, but only at some specific places I repetitively experienced freezing rain. One common factor at these places was relatively more air pollution. Could it be that pollution is a contributing factor that causes freezing rain to occur?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If not, what are the main factors that cause freezing rain, and the regions on Earth that often experience them, especially in Europe?&lt;/p&gt;&#xA;" OwnerUserId="14983" LastEditorUserId="11908" LastEditDate="2019-01-27T19:12:08.733" LastActivityDate="2019-04-25T08:18:22.903" Title="Is pollution a contributing factor to freezing rain?" Tags="|meteorology|atmosphere|climate|air-pollution|rain|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16071" PostTypeId="1" AcceptedAnswerId="16073" CreationDate="2019-01-27T17:54:45.050" Score="6" ViewCount="47" Body="&lt;p&gt;Are icebergs neutral actors in the environment, or do they have any impact on the local ecology.  Do they have any environmental impacts that might influence any part of the biosphere?&lt;/p&gt;&#xA;" OwnerUserId="14986" LastEditorUserId="11908" LastEditDate="2019-01-27T19:26:46.140" LastActivityDate="2019-01-27T19:26:46.140" Title="Do icebergs have any impact on ecology?" Tags="|ocean|glaciology|ice|ecology|cryosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16072" PostTypeId="2" ParentId="16070" CreationDate="2019-01-27T19:11:00.183" Score="4" Body="&lt;p&gt;Pollution shouldn't contribute to produce freezing rain. It might have an impact in the precipitation rate and location but not on the likelihood of freezing rain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Freezing rain requires not only that the near-surface temperature is below freezing, but also that there is a temperature inversion that provides above zero temperature in the atmospheric layers above the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Usually temperature drops as you go higher into the atmosphere. But in some areas, due to climate, geography and local weather patterns, you can often find that the temperature rises as you go up, that's called a temperature inversion (eventually as you go high enough the inversion dies and temperatures drops as you go even higher).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Such condition can melt the snow high in the atmosphere and then the water droplets enter an area near the surface that is below zero and cools them down but not for long enough to freeze solid (something that would produce sleet). Water droplets in such conditions gets below zero but remain liquid, a phenomena called supercooling. When the supercooled drops hit the surface (that is also below zero), they instantly freeze forming a thin layer of ice, hence freezing rain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This figure from &lt;a href=&quot;https://blogs.mprnews.org/updraft/2018/12/icy-start-today-40s-ahead/&quot; rel=&quot;nofollow noreferrer&quot;&gt;mprnews.org&lt;/a&gt; nicely summarize the phenomena:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/K4VhH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/K4VhH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding why some places can be mor suitable for freezing rain, I'll highlight here the comment by @Anirudh pointing to &lt;a href=&quot;http://english.cas.cn/newsroom/research_news/201507/t20150721_150589.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;this link that deals with the case of Guizhou Province in China&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-01-28T16:58:17.180" LastActivityDate="2019-01-28T16:58:17.180" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16073" PostTypeId="2" ParentId="16071" CreationDate="2019-01-27T19:26:07.640" Score="4" Body="&lt;p&gt;Yes, they have many impacts:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;They provide a substrate for algae to grow and they can have whole ecosystems under them. You might think that such substrate is transient because it is melting, but Arctic and Antarctic waters are often below zero degrees Celsius, therefore, freshwater ice doesn't melt. You can find many articles about such ecosystems (&lt;a href=&quot;https://researchfeatures.com/2017/12/21/links-between-melting-ice-ecosystems/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here is one&lt;/a&gt;).&lt;/li&gt;&#xA;&lt;li&gt;They transport sediments and nutrients into the ocean.&lt;/li&gt;&#xA;&lt;li&gt;They provide safe rest areas for animals like seals, birds and penguins.&lt;/li&gt;&#xA;&lt;li&gt;They impact the temperature of surface waters, specially in fjords.&lt;/li&gt;&#xA;&lt;li&gt;They stir the sea floor in shallow waters&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;And there must be more ways they impact the environment and ecosystems but those are the ones I can think about right now.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-01-27T19:26:07.640" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16076" PostTypeId="1" AcceptedAnswerId="16102" CreationDate="2019-01-27T20:43:18.420" Score="2" ViewCount="576" Body="&lt;p&gt;Can enough salt particulates be in the air to create salty snow or ice that is undrinkable? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Will ice form in sub zero temperatures through condensation in salty air? &lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="11908" LastEditDate="2019-01-27T20:48:26.493" LastActivityDate="2019-01-29T21:33:51.630" Title="How salty can snow/sleet be?" Tags="|minerals|ice|particulates|" AnswerCount="1" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="16078" PostTypeId="1" AcceptedAnswerId="16079" CreationDate="2019-01-27T21:48:13.283" Score="38" ViewCount="11584" Body="&lt;p&gt;I'm discussing climate change with a friend who is a climate change denier, basically the argument is that looking at this graph, is not clear that something unusual is going on, so the sea level rise is just something that was there, all natural not caused by human activity. Could you please explain this ?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/1rldH.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1rldH.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14988" LastEditorUserId="11908" LastEditDate="2019-01-27T22:42:28.663" LastActivityDate="2023-04-15T06:55:13.953" Title="Is the sea level rise unusual?" Tags="|climate-change|sea-level|" AnswerCount="7" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="16079" PostTypeId="2" ParentId="16078" CreationDate="2019-01-27T22:33:54.720" Score="72" Body="&lt;p&gt;The problem is the &lt;strong&gt;increase&lt;/strong&gt; in the &lt;strong&gt;rate&lt;/strong&gt; of sea level rise. I pulled out some approximate numbers from the figure you presented:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AXhoH.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AXhoH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can you see now how the sea level is rising much faster today than a century ago?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sea level rise, as well as climate change are normal things on Earth history. However, most times they happen at a very slow rate, allowing ecosystems and other processes to adapt to the change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, if the climate changes over several hundreds of years, animals and even tree populations can &quot;move&quot; towards the side of their distribution where climate is still good for them. But if the climate changes in 50 years, all the trees can die before they had time to grow in the areas where they could thrive in the new climate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case of sea level rise. The delta of a river for example, stays in equilibrium with the sea level because of the accumulation of sediments carried by the river. If the sea level rises slowly, the sediments can fill the delta and keep it roughly at sea level. But if the see level rises too quick for the sedimentation to keep up, it will be flooded by the sea, killing all the animals and people that live on such fertile environments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Analogously, coastal infrastructure have a given lifetime. Let's say 50 years. If the sea level doesn't change much over that period (8.5 cm at the 1880-1940 rate), there is no problem. Once the infrastructure gets replaced, the new building will be set a bit higher.&#xA;However, in the next 50 years the sea level could rise 50 cm, or even more (it would be 19 cm if we assume the last rate from the figure won't increase any further), and that is a big deal. That could mean that much coastal infrastructure will be flooded, and maybe destroyed during storms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In places like Bangladesh there are hundred of millions of people that could be displaced due to sea level rise if the rate keeps increasing. People that will also need to find a new home.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Coastal infrastructure loss, coastal erosion and immigration could be some of the worst expressions of &lt;strong&gt;fast&lt;/strong&gt; sea level rise. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;ADDITION&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given the interest risen by this question I'm adding here some data beyond what is presented by the OP, and brought to my attention by @Bobson in the comments. It comes from the paper &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2008GL033611&quot; rel=&quot;noreferrer&quot;&gt;Recent global sea level acceleration started over 200 years ago?&lt;/a&gt; and shows a sea level reconstruction going back to 1700, and it shows also the changes in rate over that period. This is summarized in their figure 3:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NFD7a.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NFD7a.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here you can clearly see how, with some ups and downs, the rate of sea level rise have been increasing over the last few centuries. And notably the current rate, about 20 years after the end of this plot is already out of the scale, and around &lt;a href=&quot;https://climate.nasa.gov/vital-signs/sea-level/&quot; rel=&quot;noreferrer&quot;&gt;3.2 mm/year&lt;/a&gt; as pointed also by other answers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would highlight the following from their abstract:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Sea level rose by 6 cm during the 19th century and 19 cm in the 20th&#xA;  century.Superimposed on the long-term acceleration are quasi-periodic&#xA;  fluctuations with a period of about 60 years. If the conditions that&#xA;  established the acceleration continue,then sea level will rise 34 cm&#xA;  over the 21st century. Longtime constants in oceanic heat content and&#xA;  increased ice sheet melting imply  that  the latest&#xA;  Intergovernmental Panel on Climate Change (IPCC) estimates of sea&#xA;  level are probably too low.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Regarding to whether this is caused by humans or not, I rather stay out of that argument and point that our best science and models suggest that lowering &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; emissions can make a significant impact in slowing down sea level rise in the upcoming centuries, so &lt;strong&gt;we should ACT NOW, and stop arguing whether it was or not our fault in the first place&lt;/strong&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-01-29T21:44:54.857" LastActivityDate="2019-01-29T21:44:54.857" CommentCount="30" ContentLicense="CC BY-SA 4.0" />
  <row Id="16080" PostTypeId="2" ParentId="16078" CreationDate="2019-01-28T03:37:16.800" Score="14" Body="&lt;p&gt;The problem is that sea level is increasing faster than ever in last couple thousand years. It is currently rising at &lt;a href=&quot;https://climate.nasa.gov/vital-signs/sea-level/&quot; rel=&quot;noreferrer&quot;&gt;3.2 mm/year according to satellite data&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XufIa.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XufIa.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The curve you showed is not a straight line, it is rising at an increasing rate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And the trend is expected to continue: The &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/sites/2/2018/11/SR15_Chapter3_Low_Res-1.pdf&quot; rel=&quot;noreferrer&quot;&gt;last IPCC report (2018)&lt;/a&gt; on the subject say:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Projections vary in the range 0.26–0.77 m and 0.35–0.93 m for 1.5°C&#xA;  and 2°C respectively for the 17–84% confidence interval (0.20–0.99 m&#xA;  and 0.24–1.17 m for the 5–95% confidence interval).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And projected sea level incrase for year 2100 are summarized in table 3.1:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EhMbd.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EhMbd.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12251" LastActivityDate="2019-01-28T03:37:16.800" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16081" PostTypeId="2" ParentId="16065" CreationDate="2019-01-28T06:00:43.593" Score="1" Body="&lt;p&gt;I don't exactly know what are you looking for, but based my own wild guess and hopefully you will be able to get your Landsat data (ready for analysis) from earth-science.&#xA;&lt;a href=&quot;https://search.earthdata.nasa.gov/search/granules?p=C1452914042-USGS_EROS&amp;amp;tl=1532843869!4!!&amp;amp;q=Landsat&amp;amp;ok=Landsat&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://search.earthdata.nasa.gov/search/granules?p=C1452914042-USGS_EROS&amp;amp;tl=1532843869!4!!&amp;amp;q=Landsat&amp;amp;ok=Landsat&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;cheers &lt;/p&gt;&#xA;" OwnerUserId="8158" LastActivityDate="2019-01-28T06:00:43.593" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16082" PostTypeId="2" ParentId="42" CreationDate="2019-01-28T06:16:00.873" Score="2" Body="&lt;p&gt;Thats a very heavy question and might need a dozen pages to briefly answer, but however its better to summarize the answer and refer to the most detailed review work of Pin Xian Wang and his team entitled &quot;&lt;a href=&quot;https://doi.org/10.1016/j.earscirev.2017.07.006&quot; rel=&quot;nofollow noreferrer&quot;&gt;The global monsoon across time scales: Mechanisms and outstanding issues&lt;/a&gt;&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope this can answer all the questions anyone have in mind. General definition can be that (Global Monsoon (GM) as a planetary scale circulation system. The primary driver of the GM is solar insolation, and the specific features in the underlying surface, such as land-sea distribution, topography, and oceanic circulations, are mainly responsible for the differences among regional monsoon systems.) derived from the above work.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most important point to be considered that the paper listed above is based on CMIP5 models, however many authors in the region have documented the deviations and differences in all CMIP5 models globally. I will also suggest the work of &lt;a href=&quot;https://scholar.google.com/citations?user=aQN9yscAAAAJ&amp;amp;hl=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;Alexis Berg&lt;/a&gt; for African monsoon system.&lt;/p&gt;&#xA;" OwnerUserId="8158" LastEditorUserId="106" LastEditDate="2019-01-28T10:51:37.747" LastActivityDate="2019-01-28T10:51:37.747" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16083" PostTypeId="1" CreationDate="2019-01-28T06:16:04.763" Score="3" ViewCount="145" Body="&lt;p&gt;I live near Sydney, Australia and I really like the idea of sourcing my own ore from the wilderness. I want to give my kids a really hands on education into how primitive industries actually kicked off.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there some source of public information explaining exactly where you would find surface deposits of ore? Is this going to be achievable for a lay person?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit:&#xA;I'm thinking of copper ore, for example, which can be smelted into pea sized droplets relatively easily using a makeshift clay furnace with bellows. I didn't specify exactly which ore because I realise that ore is regional. I realise that it is unlawful to steal materials out of the environment, but I'm assuming that the likelihood of being prosecuted for conducting a small scale science experiment for your kids is relatively low. taking a couple buckets of gravel is not going to cause an environmental disaster. If the land is privately owned then it may be a matter of simply asking the landowner for permission.&lt;/p&gt;&#xA;" OwnerUserId="14994" LastEditorUserId="14994" LastEditDate="2019-01-28T09:33:56.080" LastActivityDate="2019-01-28T09:40:34.280" Title="how can a complete novice find ore?" Tags="|ore|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16084" PostTypeId="2" ParentId="16078" CreationDate="2019-01-28T07:59:56.420" Score="8" Body="&lt;p&gt;In addition to other answers...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This curve isn't a good comparison to the &quot;natural&quot; state of the Earth, because it starts in 1880. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Industrial_Revolution&quot; rel=&quot;noreferrer&quot;&gt;Industrial Revolution&lt;/a&gt; had been in full swing for some time by then, and by that point it had been fuelled by coal for around a century. Every factory was powered by coal, every house was heated by coal or coal gas, and every light used coal gas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even then, the Earth's temperature and sea level graphs didn't change too dramatically. By the mid-20th century though, climate models fitted to past data &lt;a href=&quot;https://en.wikipedia.org/wiki/Global_cooling&quot; rel=&quot;noreferrer&quot;&gt;were extrapolating to a mini Ice Age&lt;/a&gt;. No big deal - the climate cycles like that, &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;noreferrer&quot;&gt;as the historical climate record shows&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Except the climate didn't behave that way. Instead of following the natural cycles that have been observed over hundreds of years, the temperature escalated as the graph shows. So climate scientists had to improve their models to cover dramatic differences to &quot;normal&quot; climate behaviour, modelling climate events which normally would only be seen in a disaster &lt;a href=&quot;https://www.skepticalscience.com/volcanoes-and-global-warming.htm&quot; rel=&quot;noreferrer&quot;&gt;such as massive volcanic eruptions&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The result is that &lt;a href=&quot;https://en.wikipedia.org/wiki/History_of_climate_change_science&quot; rel=&quot;noreferrer&quot;&gt;with all this work, they can predict&lt;/a&gt; a lot of the causes and effects of rising global temperatures due to fossil fuel usage (amongst other things). Your friend needs to not just look at the graph of what the Earth is currently doing, but also consider what climate scientists even as far as the 1970s who looked at the historical record were expecting the Earth to do, which assumed not burning stuff.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even then, the Earth will survive. The idea of &quot;saving the Earth&quot; is nonsense - the Earth will survive. Many species will go extinct, but that's happened a lot in the past too. Many major cities (and some entire countries) will be lost too, which is more of an issue for humans. The question is whether your friend is prepared to accept humans having control over whether this happens or not.&lt;/p&gt;&#xA;" OwnerUserId="14995" LastEditorUserId="14995" LastEditDate="2019-01-28T16:44:30.180" LastActivityDate="2019-01-28T16:44:30.180" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="16085" PostTypeId="2" ParentId="16083" CreationDate="2019-01-28T08:50:45.980" Score="1" Body="&lt;p&gt;This somewhat of a naive question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Firstly what type of ore do you want: iron ore, gold, tin, nickel, copper, silver-lead-zinc, lithium, ... etc. Also, the difference between an ore deposit and a mineral deposit is economics - can profit be made by digging it up, processing it and turning it into a saleable commodity: gold bars, ingot or sheets of copper, concentrate of certain metal sulphides.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other thing is, if you found something, what are you going to do with it. Within Australia there are laws and regulations regarding what can and can't be done regarding mineral resources. This is partly due to the State wanting it's cut via royalties and so the environment is supposedly looked after and neighbors are not affected - people living in towns etc. The State doesn't want to waste money cleaning up someone's environmental damage!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other thing is, mineral deposits occur in certain types of geological settings. It's unlikely you'll find gold or iron ore in Sydney, but you will find coal. Geological knowledge is critical to be able to find most mineral deposits. Additionally, most surface deposits have either been mined or deemed uneconomic. To find something valuable it will most likely be covered by a thickness of rock or regolith.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other thing is, if you happen to stumble on something, it might be pegged by an exploration or mining company. Removing anything from such leases is an unlawful act and if you are found you could face legal action. However, you may have limited rights to explore for some things provided you have a Prospector's Permit for the state or territory where you want to search.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All minerals in Australia are owned by the Crown (effectively the State or Territory), you can't go grabbing stuff just because you want to. If you own property in Australia, you only have rights to the top 100 metres. A mining company can legally mine under you house if the mine is greater than 100 metres in depth and the company has the necessary leases, permits and authorities from the State or Territory government authorities.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-01-28T08:50:45.980" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16086" PostTypeId="2" ParentId="16078" CreationDate="2019-01-28T09:37:10.633" Score="12" Body="&lt;p&gt;Sea level rise from thermal expansion is a very slow process: oceans are 3.7 km deep on average, and water has a very large &lt;a href=&quot;https://en.wikipedia.org/wiki/Heat_capacity&quot; rel=&quot;noreferrer&quot;&gt;specific heat capacity&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's a related diagram from the &lt;a href=&quot;https://web.archive.org/web/20080510080424/https://www.ipcc.ch/pdf/climate-changes-2001/synthesis-syr/english/summary-policymakers.pdf&quot; rel=&quot;noreferrer&quot;&gt;IPCC Third Assessment Report&lt;/a&gt; (page 17):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/TTwjJ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TTwjJ.jpg&quot; alt=&quot;sea level rise after emissions are reduced&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Climate change didn't have much impact on the sea level, &lt;em&gt;yet&lt;/em&gt;.&lt;/p&gt;&#xA;" OwnerUserId="12617" LastEditorUserId="725" LastEditDate="2019-01-28T10:26:33.240" LastActivityDate="2019-01-28T10:26:33.240" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="16087" PostTypeId="2" ParentId="16083" CreationDate="2019-01-28T09:40:34.280" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;how can a complete novice find ore?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You don't.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to Fred's excellent answer regarding the legalities of the matter, I would add the following:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;All of the easy stuff has already been found, and finding any more ore requires efforts beyond what you can do on your own.&lt;/li&gt;&#xA;&lt;li&gt;Stuff that is easy to find now is commonly in old mines or old mine tailings. These are dangerous places to be in. There is risk of collapse, acid mine drainage, and a bunch of other nasty things.&lt;/li&gt;&#xA;&lt;li&gt;Learning how to find &quot;ore&quot; regardless of the first two points requires proper education in geological sciences.&lt;/li&gt;&#xA;&lt;li&gt;Smelting copper ore, as per your idea, is a bad bad bad idea. Copper ore is usually in the form of copper sulfides. You really don't want to breath sulfur-bearing gases while you're smelting the ore.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;If you are interested in looking for minerals and such, as a resident of New South Wales I recommend you talk a look at this website:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.resourcesandgeoscience.nsw.gov.au/miners-and-explorers/fossicking-in-nsw&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.resourcesandgeoscience.nsw.gov.au/miners-and-explorers/fossicking-in-nsw&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It contains information and resources that might be useful to you.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-01-28T09:40:34.280" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16088" PostTypeId="2" ParentId="5152" CreationDate="2019-01-28T20:35:31.650" Score="0" Body="&lt;p&gt;One benefit is a higher degree of accuracy (&lt;a href=&quot;https://blogdredd.blogspot.com/2018/12/in-search-of-ocean-heat-3.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;In Search Of Ocean Heat - 3&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another is thermodynamic proportion (&lt;a href=&quot;https://blogdredd.blogspot.com/2019/01/patterns-conservative-temperature.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Patterns: Conservative Temperature &amp;amp; Potential Enthalpy - 3&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="14376" LastActivityDate="2019-01-28T20:35:31.650" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16089" PostTypeId="1" CreationDate="2019-01-28T21:46:08.610" Score="1" ViewCount="36" Body="&lt;p&gt;Does anyone know if it is possible to get a gravity map of a specific region of Greenland? &#xA;The data I've found here &lt;a href=&quot;http://icgem.gfz-potsdam.de/vis3d/longtime&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://icgem.gfz-potsdam.de/vis3d/longtime&lt;/a&gt; , are simply of to low spatial resolution. I need to get it down to Sentinel-2 levels. Around 10-60 meters pr. pixel.&#xA;I cannot for the life of me figure out how to use GOCE USER TOOLBOX to produce a gravity anomaly map with GOCE data. &lt;/p&gt;&#xA;" OwnerUserId="14512" LastActivityDate="2019-01-28T21:46:08.610" Title="Detailed gravity maps" Tags="|satellites|gravity|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16090" PostTypeId="2" ParentId="15011" CreationDate="2019-01-28T23:07:50.527" Score="3" Body="&lt;p&gt;From [1, 2], the oceans are dissipating about 3.5 TW of energy. The moon and sun input about 3.2 TW and 0.5 TW, respectively. (0.2 TW of the 3.7 TW are dissipated by the solid Earth and the atmosphere.) Another estimate of tidal energy dissipation [3], looking at the 8 major tidal constituents, estimates 0.411 TW of solar tides dissipated by the ocean. (With an additional 0.03 TW dissipated by a moon-sun interaction constituent.)   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1]: Munk and Wunsch, 1998, &lt;a href=&quot;https://doi.org/10.1016/S0967-0637(98)00070-3&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/S0967-0637(98)00070-3&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[2]: Jayne and Laurent, 2001, &lt;a href=&quot;https://doi.org/10.1029/2000GL012044&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1029/2000GL012044&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[3]: Egbert and Ray, 2003, &lt;a href=&quot;https://doi.org/10.1029/2003GL017676&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1029/2003GL017676&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11269" LastEditorUserId="7314" LastEditDate="2019-01-29T04:28:25.890" LastActivityDate="2019-01-29T04:28:25.890" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16091" PostTypeId="2" ParentId="16000" CreationDate="2019-01-29T00:22:20.123" Score="2" Body="&lt;p&gt;There are some wonderful answers here, but I think a simplified plain English answer would be helpful. Barring any nearby mountains, and various foibles, the closest point to the sun at the June solstice is where it is midday on the tropic of Cancer. At the December solstice, it is where it is midday on the tropic of Capricorn. At equinox it is where it is midday on the equator. Other times of year it is a proportional point in between (no doubt described mathematically by the above equations).&lt;/p&gt;&#xA;" OwnerUserId="15014" LastActivityDate="2019-01-29T00:22:20.123" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16092" PostTypeId="2" ParentId="15922" CreationDate="2019-01-29T06:18:55.827" Score="3" Body="&lt;p&gt;I just want to add couple more  points that are not covered in the excellent answer above by dplmmr. It is the fact that lenticular clouds do not form in the trough part of the wave because that corresponds to air that is warming but they do form in the crest of waves as air parcels condense. How does one obtain the trough and crest of the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Mountain_wave&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mountain wave&lt;/a&gt; that produced the lenticular cloud? Well you use a cloud resolving model-&lt;a href=&quot;https://atmos.washington.edu/~durrand/pdfs/Hills_Durran_qjrms_2014.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cloud resolving models&lt;/a&gt;(these models are typically non hydrostatic) and then plot the streamlines. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The flat bottom of the lenticular cloud is as a consequence of level of condensation and and the curved top is as a consequence of the wave crest. These lenticular clouds are stationary wave clouds. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-01-29T09:45:08.577" LastActivityDate="2019-01-29T09:45:08.577" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="16093" PostTypeId="1" AcceptedAnswerId="16096" CreationDate="2019-01-29T07:44:26.650" Score="10" ViewCount="4389" Body="&lt;p&gt;&lt;a href=&quot;https://www.forbes.com/sites/jamestaylor/2013/02/13/peer-reviewed-survey-finds-majority-of-scientists-skeptical-of-global-warming-crisis/#5b43c8474c7c&quot; rel=&quot;noreferrer&quot;&gt;This&lt;/a&gt; Forbes article from 2013 (archive link &lt;a href=&quot;https://web.archive.org/web/20190126222459/https://www.forbes.com/sites/jamestaylor/2013/02/13/peer-reviewed-survey-finds-majority-of-scientists-skeptical-of-global-warming-crisis/&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;) with the headline &lt;strong&gt;&quot;Majority Of Scientists Skeptical Of Global Warming Crisis&quot;&lt;/strong&gt; gets brandied around a lot. It states that &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Only 36 percent of geoscientists and engineers believe that humans are&#xA;  creating a global warming crisis, according to a survey reported in&#xA;  the peer-reviewed Organization Studies. By contrast, a strong majority&#xA;  of the 1,077 respondents believe that nature is the primary cause of&#xA;  recent global warming and/or that future global warming will not be a&#xA;  very serious problem.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Also, 14% of the respondents replied that :&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;“they strongly disagree that climate change poses any significant&#xA;  public risk and see no impact on their personal lives.”&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The article is reporting the paper Lefsrud and Meyer (2012) &quot;&lt;a href=&quot;https://doi.org/10.1177/0170840612463317&quot; rel=&quot;noreferrer&quot;&gt;Science or Science Fiction? Professionals’ Discursive Construction of Climate Change&lt;/a&gt;&quot;, Organization Studies, 33(11), pp. 1477–1506.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to know if that article has been refuted anywhere, and (if the information is misleading), how can a layperson recognize that, given that its published in such a renowned magazine.&lt;/p&gt;&#xA;" OwnerUserId="516" LastEditorUserId="516" LastEditDate="2019-01-31T05:26:15.910" LastActivityDate="2019-03-13T03:26:34.750" Title="Does this peer-reviewed study (referenced in Forbes) contradict the accepted position that climate change is real?" Tags="|climate-change|climate-models|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16095" PostTypeId="1" AcceptedAnswerId="16101" CreationDate="2019-01-29T09:56:33.333" Score="1" ViewCount="161" Body="&lt;p&gt;I have searched Google for almost an hour with no result. I'm looking for something like, &quot;Indonesia, January to August is rain season, September to December is hot season&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can't use the old information in books about seasonal change that now seem to have shifted and I can't find any updated information anywhere.&lt;/p&gt;&#xA;" OwnerUserId="15024" LastEditorUserId="11908" LastEditDate="2019-03-11T21:15:20.897" LastActivityDate="2019-03-11T21:15:20.897" Title="Where can I find information about monthly seasonal change in a given area?" Tags="|meteorology|climate|seasons|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16096" PostTypeId="2" ParentId="16093" CreationDate="2019-01-29T10:12:29.980" Score="41" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;I want to know if that article has been refuted anywhere&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes. You can read all about it in the blog post &lt;a href=&quot;http://www.climatesciencewatch.org/2013/02/14/james-taylor-misinterprets-study-by-180-degrees/&quot; rel=&quot;noreferrer&quot;&gt;&#xA;James Taylor misinterprets study by 180 degrees&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short, the original paper was designed to test the view of &quot;professional geologists&quot;, which in this case are members of the Association of Professional Engineers and Geoscientists of Alberta. The vast majority of them work in the fossil fuel industry. Therefore, those are people whose livelihood depends on the extraction of fossils fuels. This is not exactly the most unbiased crowd...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The article by James Taylor is spinning the original study into claiming that it applies to all geoscientists. The original authors of the study actually replied to Taylor's article saying:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;First and foremost, our study is not a representative survey. Although&#xA;  our data set is large and diverse enough for our research questions,&#xA;  it cannot be used for generalizations such as “respondents believe …”&#xA;  or “scientists don’t believe …”&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(This is taken from a secondary source &lt;a href=&quot;https://scholarsandrogues.com/2013/02/18/heartland-institute-taylor-makes-false-claims-about-new-study/&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short, the article is not &lt;em&gt;from&lt;/em&gt; &quot;Forbes&quot; (&lt;em&gt;i.e.&lt;/em&gt;, presenting the opinion of Forbes magazine). It was published &lt;em&gt;in&lt;/em&gt; Forbes, but written by a lying climate denier. He has misinterpreted the original study, as evident by two independent analyses and by the reply of the authors themselves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to answer your question:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Does this peer-reviewed study contradict the accepted position that climate change is real?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This peer-reviewed study does not contradict anything. Climate change is overwhelmingly accepted by all scientists. What this peer-reviewed study shows is that those who deny the realities of climate change are those employed by the fossil fuel industry, particularly people in top management positions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, quoting myself from the comments:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The study correctly showed that people employed by the fossil fuel&#xA;  industry tend to disagree that climate change is anthropogenic. The&#xA;  Forbes article generalised this to all scientists. This is wrong. The&#xA;  authors of the study said this is wrong.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;I will finish with some anecdotes. I am a geoscientist at a top Australian University. Every single one of the scientists here accept the climate change is a major threat to modern human civilisation as we know it. In a previous university where many people were involved with fossil fuel research, people accepted the realities of climate change. They were involved with the research because they either tried to find better ways of fossil fuels (realising that renewables are not there yet, and nuclear is unfortunately not an option), or because they have to pay their rent and feed their children. None denied that climate change is real, and none denied that the fossil fuel industry is the leading cause of it. We geoscientists all understand that the major driving force of the fossil fuel industry and climate change denialism is political, financial (usually old white rich men who don't care about anything but their own monetary benefit) and not scientific.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="595" LastEditDate="2019-01-31T12:22:30.153" LastActivityDate="2019-01-31T12:22:30.153" CommentCount="17" ContentLicense="CC BY-SA 4.0" />
  <row Id="16099" PostTypeId="1" CreationDate="2019-01-29T18:10:02.773" Score="9" ViewCount="534" Body="&lt;p&gt;Is it possible for an earthquake to generate such a design in a sand pendulum during an earthquake? I saw an article online describing the story of a shop owner finding one of his pendulums had created this image during an earthquake. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I researched seismographs and they all seem to be in a linear fashion. Obviously a pendulum is not a scientific seismograph which raises the question: is this possible? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I could not find any research debunking this concept nor confirming. All the articles I read were different news groups reiterating the same story. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QlicX.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QlicX.jpg&quot; alt=&quot;This image is of a sand pendulum design that a shop owner claims was created during the 45 second earthquake in Olympia, WA in 2001&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6195" LastActivityDate="2019-01-29T18:27:22.820" Title="Could an earthquake create a design in a sand pendulum?" Tags="|earthquakes|seismology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16100" PostTypeId="2" ParentId="16099" CreationDate="2019-01-29T18:27:22.820" Score="2" Body="&lt;p&gt;Interesting images, thanks for sharing them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think its quite likely that a sand pendulum would act as a type of seismograph.  I'm more in geochemistry than geophysics side of things but this kind of pattern does not seem at all inconsistent with seismic shaking.  The linear nature of a recording seismograph is because it is designed to record against a time scale which is perpendicular to the &quot;movement&quot; scale.  Even if movement had a stronger direction in the ground, the table and building this sand pendulum is in would translate the shaking movement into additional directions.  There were multiple movements to make the pattern shown.  It defiantly looks like more than just a truck or subway going by!&lt;/p&gt;&#xA;" OwnerUserId="1396" LastActivityDate="2019-01-29T18:27:22.820" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16101" PostTypeId="2" ParentId="16095" CreationDate="2019-01-29T20:05:58.593" Score="2" Body="&lt;p&gt;You can try &lt;a href=&quot;http://www.climatemps.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;climatemps.com&lt;/a&gt; for easy access and plots. There they have a map you can click on or a list by countries.&#xA;More data and analysis tools are available at the &lt;a href=&quot;https://climexp.knmi.nl/selectstation.cgi?id=d17099be003bf17970040ea12c50ad61&quot; rel=&quot;nofollow noreferrer&quot;&gt;KNMI Climate Explorer&lt;/a&gt;, a more reliable and scientifically sound source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is one of the outputs for Jakarta from &lt;a href=&quot;http://www.jakarta.climatemps.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;jakarta.climatemps.com&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3AczD.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3AczD.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-01-29T20:05:58.593" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16102" PostTypeId="2" ParentId="16076" CreationDate="2019-01-29T21:33:51.630" Score="1" Body="&lt;p&gt;Considering there are evaporation ponds worldwide (San Francisco Bay is full of them, and Morton used to, and may still, have the majority) used for harvesting sea salt, it's doubtful that any salt deposits would end up in the Martian atmosphere. And the atmosphere of Mars is too thin to hold salt blown from existing salt deposits, so salt blown into the atmosphere by Martian dust storms would quickly settle out of the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2019-01-29T21:33:51.630" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16103" PostTypeId="2" ParentId="15749" CreationDate="2019-01-29T22:50:30.603" Score="4" Body="&lt;p&gt;You’re right that there were no future natural forcings experiments defined in the CMIP5 protocol.  The reason being simply that the modeling groups thought that other experiments were more deserving of their limited computing time.  Compare this with the much stronger call for the historicalNat and historicalGHG experiments, which were required for detection and attribution studies.  Individual modeling centers may have run future natural forcings experiments, but that will be hit and miss, and there wasn’t an experiment name to lodge the outputs to in the CMIP5 database.  Incidentally, the situation with the RCP (all forcings) experiments themselves was actually a bit imperfect, because the implementations of future natural forcings were left to the discretion of each modeling group:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ol start=&quot;5&quot;&gt;&#xA;  &lt;li&gt;… It is recommended that either volcanic aerosols should be omitted entirely from the control and future runs, or, alternatively, the same background aerosol should be prescribed in both runs.&lt;/li&gt;&#xA;  &lt;li&gt;It is recommended that some representation of the solar cycle be included in the 20th and 21st century simulations, though that is left up to the discretion of the modeling groups.&lt;/li&gt;&#xA;  &lt;/ol&gt;&#xA;  &#xA;  &lt;p&gt;Source: Taylor et al (2011).  A summary of the CMIP5 experiment design. (&lt;a href=&quot;https://cmip.llnl.gov/cmip5/docs/Taylor_CMIP5_design.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;pdf&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There was a further &lt;a href=&quot;http://solarisheppa.geomar.de/cmip5&quot; rel=&quot;nofollow noreferrer&quot;&gt;recommendation&lt;/a&gt; for how future solar irradiance forcing should be represented: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In CMIP5, climate projections were based on a stationary-Sun scenario, obtained by simply repeating solar cycle 23, which ran from April 1996 to June 2008 (Lean and Rind, 2009).&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: Matthes et al (2017).  Solar forcing for CMIP6 (v3.2), Geosci. Model Dev., 10, 2247-2302, &lt;a href=&quot;https://doi.org/10.5194/gmd-10-2247-2017&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.5194/gmd-10-2247-2017&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But, in practice, groups did slightly different things from each other, so you usually have to check the output file metadata and any associated journal papers for individual model runs to get an idea of the details.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is clearly not a crazy question though, because in CMIP6 some future natural forcings experiments have been defined, albeit in the lower priority tiers. Specifically, the Detection and Attribution MIP (DAMIP) includes &lt;a href=&quot;https://view.es-doc.org/?renderMethod=id&amp;amp;project=cmip6&amp;amp;id=f906e17f-1b29-40bc-9140-fbb035a2b8d9&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;ssp245-GHG&quot;&gt;ssp245-GHG&lt;/a&gt; and &lt;a href=&quot;https://view.es-doc.org/?renderMethod=id&amp;amp;project=cmip6&amp;amp;id=4966bb28-934e-40d5-a1bf-91a2827c4aa6&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;ssp245-nat&quot;&gt;ssp245-nat&lt;/a&gt; experiments, and the volcano MIP (&lt;a href=&quot;https://doi.org/10.5194/gmd-9-2701-2016&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;VolMIP&quot;&gt;VolMIP&lt;/a&gt;) has the &lt;a href=&quot;https://view.es-doc.org/?renderMethod=id&amp;amp;project=cmip6&amp;amp;id=8dbad2a5-640b-4fb8-93d2-3fdeb0bd3ef9&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;volc-cluster-21c&quot;&gt;volc-cluster-21C&lt;/a&gt; experiment.  If you dig down into those you’ll find that future solar variability is derived more or less the way you describe, i.e., projecting forward based on a set of statistical time series models trained on past variability.  Note, however, that Matthes et al are careful to point out that this is a projection not a prediction:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;As of today, predicting solar activity up to 2300 is very challenging, if not impossible… The unusually long solar cycle number 23 that ended in 2009, and the weak one (no. 24) that followed came as a surprise, and manifested our evident lack of understanding of the solar cycle.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Conversely, future volcanic forcing in ssp245-nat will be prescribed as a near-constant background forcing:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Volcanic forcing will be ramped up from the value at the end of the historical simulation period (2015) over 10 years to the same constant value prescribed for the piControl simulations in the DECK, and then will be kept fixed.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: O'Neill et al (2016). The Scenario Model Intercomparison Project (ScenarioMIP) for CMIP6. Geosci. Model Dev., 9, 3461-3482, &lt;a href=&quot;http://doi.org/10.5194/gmd-9-3461-2016&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://doi.org/10.5194/gmd-9-3461-2016&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So why not a statistical model for volcanic emissions?  This forcing is episodic rather than cyclic and is prescribed to the CMIP models as several variables on latitude-height-time grids.  As you hint at in your question, this is too many degrees of freedom to pin down satisfactorily from just the 1850-2005 record.  Even if it could be done, you then have the problem of how to use the statistical model, given that each climate model will only run a few realisations of a particular projection.  Do you generate one scenario to be shared by all models, or do you let each group generate its own scenarios using the statistical model?  Either way, you can’t explore enough of the parameter space to avoid ending up with a CMIP6 ensemble containing decadal variability that is strongly influenced by forcing scenarios that are extremely unlikely to happen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I understand it, the current assumption is that volcanic forcing is stationary and, in the absence of knowing the future sequence of eruptions, its effect on slowly varying climate components like ocean heat content is best represented by a constant mean forcing.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2019-01-29T22:50:30.603" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16105" PostTypeId="1" AcceptedAnswerId="16108" CreationDate="2019-01-29T23:34:19.347" Score="10" ViewCount="421" Body="&lt;p&gt;What would cause a polar vortex to become unstable a split into 3 smaller ones? How rare is this and what long term effects could this cause if the vortex stays unstable?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.severe-weather.eu/long-range-2/update-on-the-splitting-polar-vortex-and-winter-trends-across-the-european-continent-through-mid-january/&quot; rel=&quot;noreferrer&quot;&gt;http://www.severe-weather.eu/long-range-2/update-on-the-splitting-polar-vortex-and-winter-trends-across-the-european-continent-through-mid-january/&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/KYmSF.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KYmSF.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastActivityDate="2019-02-07T03:18:31.107" Title="Unstable North Polar Vortex?" Tags="|meteorology|climate-change|poles|vorticity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16108" PostTypeId="2" ParentId="16105" CreationDate="2019-01-30T02:40:27.953" Score="11" Body="&lt;p&gt;There are two key intermittent mid latitude circulation patterns during boreal winter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One is &lt;a href=&quot;https://en.wikipedia.org/wiki/Block_(meteorology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;blocking flows&lt;/a&gt;, leading to the formation of blocking anticyclones.  One can gauge the location of blocking events through the &lt;a href=&quot;https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/block.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;CPC blocking index&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other one is &lt;a href=&quot;https://en.wikipedia.org/wiki/Sudden_stratospheric_warming&quot; rel=&quot;nofollow noreferrer&quot;&gt;sudden stratospheric warming&lt;/a&gt;, where the winds cause a disturbance such that the temperature in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Stratosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;stratosphere&lt;/a&gt; (the layer above the typical weather layer, the troposphere) warms significantly.  To view this one needs to look at the temperature change over the poles, typically by looking at the 10 hPa isobaric surface. If the temperature change is around 50 to 70 degrees Kelvin over an area of &lt;a href=&quot;https://en.wikipedia.org/wiki/Synoptic_scale_meteorology&quot; rel=&quot;nofollow noreferrer&quot;&gt;synoptic scale&lt;/a&gt; and the temperature change is rapid, over a period of 3-4 days, then you have the possibility the weather can be impacted by a sudden stratospheric warming event. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The possibility is that a sudden stratospheric warming in January 2019 could cause the &lt;a href=&quot;https://www.noaa.gov/image_download/3913?itok=5yZosn1E&quot; rel=&quot;nofollow noreferrer&quot;&gt;stratospheric polar vortex&lt;/a&gt; to split. Based on the peer reviewed reference &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/JCLI-D-12-00030.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Influence of Stratospheric Vortex Displacements and Splits on Surface Climate&lt;/a&gt; it is actually the troposphere that causes polar stratospheric variability through &lt;a href=&quot;http://www-eaps.mit.edu/~rap/courses/12831_notes/3.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;vertically propagating Rossby waves&lt;/a&gt;. The math behind that is quite complex but it also feeds off linear theory (which can be seen in the quasi-geostrophic Potential Vorticity equation). Some of these vertically propagating waves can travel all the way up into the mesosphere. &lt;a href=&quot;http://snowball.millersville.edu/~adecaria/ESCI343/esci343_lesson11_rossby_waves.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;These lecture notes on Rossby waves&lt;/a&gt; mention that Rossby waves cannot propagate vertically if the mean zonal winds are easterly or if they are westerly and exceed a certain speed. It is only the wintertime atmosphere that permits Rossby waves to reach the stratosphere and deposit energy and hence sudden stratospheric warmings are only observed after boreal fall. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the northern hemisphere most vertically propagating Rossby waves arise due to the topography.  In the southern hemisphere the sudden stratospheric warmings are a rarity due to lack of such topographical features. The last sudden stratospheric warming over the southern hemisphere was in 2002. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The resulting stratospheric anomalies can in return influence surface climate but the mechanism on how exactly this occurs is the still the matter of scientific research.  One of the theories that is currently popular is the &lt;a href=&quot;http://pordlabs.ucsd.edu/pcessi/theory2016/TEM_Vallis.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;wave mean flow interactions&lt;/a&gt;. This can be easily summarized as concerning how planetary scale Rossby waves influence the circulating zonal flows around a planet.  The other main theory is wave reflections at the tropopause. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what is the net result of either of the above two possibilities? Either way they affect mid-latitude storms. Storms could either become more intense, shift equatorward, or there could be extremely cold air advection spells as the stratospheric air gets mixed into the troposheric air. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to the rarity of polar vortex splits - they are coupled to those sudden stratospheric warmings. If you look towards the climatology of SSWs, &lt;a href=&quot;https://academiccommons.columbia.edu/doi/10.7916/D8QJ7TFG&quot; rel=&quot;nofollow noreferrer&quot;&gt;observations show that they occur more during El Niños and La Niñas than during neutral conditions&lt;/a&gt;. Sudden stratospheric warmings happen almost every other year in the NH. However sometimes the polar vortex isn't split during these events but is merely pushed equatorward. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The long term effect a polar vortex split could be extended spells of extremely cold weather in the affected areas, and when the vortex reforms on into summer it would be shrunk in size from the dispersed energy giving rise to greater easterly wind circulation near the poles. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now that the reanalysis data is available from January 2019 I want to add some visuals for the Dec-2018/Jan 2019 polar vortex split and ongoing cold wave. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://www.severe-weather.eu/long-range-2/update-on-the-splitting-polar-vortex-and-winter-trends-across-the-european-continent-through-mid-january/&quot; rel=&quot;nofollow noreferrer&quot;&gt;OP's link&lt;/a&gt;, plus &lt;a href=&quot;https://www.slashgear.com/polar-vortex-split-means-winter-is-coming-15562420/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this SlashGear article on the polar vortex split&lt;/a&gt; provide GEFS and GFS forecast data, pointing to a three-way split of the polar vortex. I went through reanalysis data from the period of Dec 18th 2018 through Jan 30th 2019 and there appears to be two separate candidate dates for a three-way split of the stratospheric polar vortex; it really depends on whether one considers the small vortex over the North Pacific as one of the split vortices or not on Jan 5th 2019. The 5th January event is the one that most closely resembles that GFS forecast data. In saying this, the reanalysis data is averaged over a full day as opposed to the single point in time of the GFS data. In the geopotential height anomaly there is a clear three way split but one must remember that the anomalies are calculated vis-a-vis the climatological period 1981-2010. Either way this will require more detailed research before the three-way split is confirmed or not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VAujw.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VAujw.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/vHFnd.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vHFnd.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/IUkfu.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IUkfu.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/8x3CK.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8x3CK.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;Finally from the reanalysis data it appears that, in contrast to the 2018 event, this year's event points to significant instability in the dynamics of the polar vortex. There are clear suggestions that the polar vortex is breaking and reforming again over short time scales, which is interesting.&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-02-07T03:18:31.107" LastActivityDate="2019-02-07T03:18:31.107" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16109" PostTypeId="1" CreationDate="2019-01-30T07:18:12.197" Score="3" ViewCount="498" Body="&lt;p&gt;I am using GRADS (&lt;a href=&quot;https://en.wikipedia.org/wiki/GrADS&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;http://cola.gmu.edu/grads/gadoc/gadoc.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;, &lt;a href=&quot;https://help.ceda.ac.uk/article/292-grads&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;) to plot ERA reanalysis relative humidity profile for latitudinal average of 15N to 37N, and along the longitude from 40E to 130E. The orography is quite obvious and thus some pressure levels like up to 700 hPa are not applicable in some regions with high altitude. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I need to know how to plot orography in the grads, thus the orography can be masked or shown in gray color, the image for reference is shown below. Thanks&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eJ2Ak.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eJ2Ak.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8158" LastEditorDisplayName="user1066" LastEditDate="2019-04-04T10:48:13.013" LastActivityDate="2022-11-26T04:55:18.710" Title="How to plot orography for vertical profile of a certain variable along pressure levels in GRADS" Tags="|meteorology|thermodynamics|topography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16111" PostTypeId="2" ParentId="16078" CreationDate="2019-01-30T14:29:37.980" Score="10" Body="&lt;p&gt;I think &lt;a href=&quot;https://xkcd.com/1732/&quot; rel=&quot;noreferrer&quot;&gt;this XKCD&lt;/a&gt; says it all:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lWHMb.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lWHMb.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15051" LastActivityDate="2019-01-30T14:29:37.980" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="16112" PostTypeId="1" AcceptedAnswerId="16127" CreationDate="2019-01-30T16:04:37.200" Score="6" ViewCount="266" Body="&lt;p&gt;I think a large portion of the earth's land is unusable from being too cold and land that is too hot does not have enough water and dries out which could be fixed by diverging water to those areas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then there is the sea levels rising so some land will be underwater but that will be an insignificant amount compared to the amount of new usable land, not to mention we could reshape land in those areas to prevent it from being underwater.&lt;/p&gt;&#xA;" OwnerUserId="15052" LastEditorUserId="11908" LastEditDate="2019-03-11T21:13:36.460" LastActivityDate="2019-03-11T21:13:36.460" Title="Would more or less land be usable if global temperatures rose?" Tags="|climate-change|climate|geography|gis|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="16113" PostTypeId="2" ParentId="16078" CreationDate="2019-01-31T02:17:12.723" Score="5" Body="&lt;p&gt;I just took the sea level elevation rate (mm/yr) graph from &lt;a href=&quot;https://earthscience.stackexchange.com/a/16079/981&quot;&gt;Camilo Rada's answer&lt;/a&gt; and added:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A vertical axis at zero (when the curve is at the point, it means the sea level did not change that year).&lt;/li&gt;&#xA;&lt;li&gt;Red and green colors showing the trend.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Hopefully it will speak more to your friend.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RssLq.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RssLq.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="981" LastActivityDate="2019-01-31T02:17:12.723" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16114" PostTypeId="1" AcceptedAnswerId="16176" CreationDate="2019-01-31T03:11:37.500" Score="3" ViewCount="231" Body="&lt;p&gt;Cleopatra's Grave is a natural feature inside (warning: PDF) &lt;a href=&quot;http://caves.org/grotto/sag/content/newsletter/LavaBeds.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Catacombs Cave&lt;/a&gt; in &lt;A HREF=&quot;https://www.nps.gov/labe/index.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lava Beds National Monument&lt;/A&gt; near &lt;a href=&quot;https://goo.gl/maps/2S47GSBxthD2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Modoc, California&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;IMG SRC=&quot;https://lookbeforeyoulive.com/wp-content/uploads/2018/09/Summer_2018_Day29_013.jpg&quot;&gt;&lt;br&gt;&#xA;&lt;sub&gt;&lt;sup&gt;Source: &lt;a href=&quot;https://lookbeforeyoulive.com/?p=24463&quot; rel=&quot;nofollow noreferrer&quot;&gt;LookBeforeYouLive&lt;/a&gt;&lt;/sup&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My apologies, as this image is somehow in really bad color, like all the other images from that blog post. (I should really be grateful they got images at all, as &lt;a href=&quot;https://www.youtube.com/watch?v=YXn5LTKWn9Y&quot; rel=&quot;nofollow noreferrer&quot;&gt;this low image quality video&lt;/a&gt; provides some idea of the difficulty of reaching the location, which requires crawling through at least eight feet of one-foot-high passage and lots of three-foot-high passage, and the ceiling directly above it is about two feet high, so I can't complain about the quality!)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I saw it with my own eyes. Cleopatra's grave is an oblong feature on the floor of Catacombs Cave (lava tube) about three feet long and two feet wide and rimmed by apparently normal cave floor that raises up about an inch or so above the surrounding floor. Cleopatra's grave is composed of rock of a light grey color as opposed to the dark grey and slightly brown-tinged floor around it. It looks very smooth (I didn't touch it because of its historic paint) and it exhibits circular fractures running two complete rings around its outer edge. It is trivially identified by the rather recent red paint serving to mark the locations of the historic yellow paint applied by J.D. Howard himself calling it by name.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The surface has no visible crystals, and if I didn't know it was natural I'd have thought on seeing it that somebody had mixed up some really fine grout (think cement) and poured it. Furthermore, the surface exhibits no specular reflection and almost perfectly uniform matte reflection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But what is it? Some kind of lava upwelling? A rafted block of unusual shape? Something else?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a locally-well-known feature that I'm hoping somebody here actually knows the answer to. But there is simply not another way of getting at it -- there's no way I'm going to test its hardness or otherwise risk damage to so much as the paint on it.&lt;/p&gt;&#xA;" OwnerUserId="1139" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T18:21:40.673" LastActivityDate="2019-08-28T18:21:40.673" Title="What kind of lava tube feature is Cleopatra's Grave?" Tags="|geology|volcanology|cavern|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16115" PostTypeId="1" AcceptedAnswerId="16117" CreationDate="2019-01-31T06:47:33.290" Score="18" ViewCount="6277" Body="&lt;p&gt;&lt;a href=&quot;https://twitter.com/NWSLaCrosse/status/1090571778139832320/photo/1&quot; rel=&quot;noreferrer&quot;&gt;This tweet&lt;/a&gt; from the National Weather Service in LaCrosse, Wisconsin, USA says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We have officially hit -30 here at the NWS La Crosse office as of 520 a.m. The wind chill is -54. Be sure to dress appropriately if you're heading out for the day.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The photo shown below shows a digital readout of an electronic thermometer, showing -30.1 but has no units. The -30's are getting close to where the Celsius and Fahrenheit scales tend to have similar numerical values, so there's no way to use context in this case to choose the most likely answer. No units are shown on the front panel, and &lt;a href=&quot;https://www.weather.gov/media/box/coop/coop_nimbus_instructions.pdf&quot; rel=&quot;noreferrer&quot;&gt;these instructions&lt;/a&gt; offer no help either.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FpOgz.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FpOgz.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="240" LastEditDate="2019-01-31T18:22:43.017" LastActivityDate="2019-01-31T18:22:43.017" Title="Does the US National Weather Service use Celsius or Fahrenheit?" Tags="|meteorology|temperature|" AnswerCount="2" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="16117" PostTypeId="2" ParentId="16115" CreationDate="2019-01-31T07:45:23.883" Score="18" Body="&lt;p&gt;&lt;a href=&quot;https://graphical.weather.gov/sectors/conus.php?element=T&quot; rel=&quot;noreferrer&quot;&gt;NWS Temperature forecast&lt;/a&gt; or &lt;a href=&quot;https://digital.weather.gov/&quot; rel=&quot;noreferrer&quot;&gt;new forecast&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From these URLs, it  appears that the unit is Fahrenheit. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;and if you click on this URL - &lt;a href=&quot;https://graphical.weather.gov/definitions/defineMaxMinT.html&quot; rel=&quot;noreferrer&quot;&gt;Max/MinT &lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is the maximum daytime or minimum overnight temperature in degrees Fahrenheit. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In the USA  NWS always used to issue forecasts and bulletins in Fahrenheit and some background can be obtained from here &lt;a href=&quot;https://en.wikipedia.org/wiki/United_States_customary_units&quot; rel=&quot;noreferrer&quot;&gt;US Customary Units&lt;/a&gt; and here - &lt;a href=&quot;https://www.vox.com/2015/2/16/8031177/america-fahrenheit&quot; rel=&quot;noreferrer&quot;&gt;Why Americans still use Fahrenheit&lt;/a&gt; as well here - &lt;a href=&quot;https://www.accuweather.com/en/weather-glossary/fahrenheit-versus-celsius-why/17969960&quot; rel=&quot;noreferrer&quot;&gt;Fahrenheit Versus Celsius: Why the US Hasn't Converted&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Degrees Fahrenheit are used in the U.S. to measure temperatures in most non-scientific contexts. The Rankine scale of absolute temperature also saw some use in thermodynamics. Scientists worldwide use the kelvin and degree Celsius. Several U.S. technical standards are expressed in Fahrenheit temperatures and American medical practitioners often use degrees Fahrenheit for body temperature. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In reality, the NWS and &lt;a href=&quot;https://www.ncdc.noaa.gov/&quot; rel=&quot;noreferrer&quot;&gt;NCDC&lt;/a&gt; weather forecast model outputs for the different systems (&lt;a href=&quot;https://en.wikipedia.org/wiki/Global_Forecast_System&quot; rel=&quot;noreferrer&quot;&gt;GFS&lt;/a&gt;, &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/model-data/model-datasets/north-american-mesoscale-forecast-system-nam&quot; rel=&quot;noreferrer&quot;&gt;NAM&lt;/a&gt;, &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/model-data/model-datasets/north-american-regional-reanalysis-narr&quot; rel=&quot;noreferrer&quot;&gt;NARR&lt;/a&gt;...) use temperatures in Kelvin. This satisfies the international standards (e.g., CF1.6 convention compliant) and also avoids issues with advecting fields (in this case) that are equal to zero in some locations. You can see this if you look at the model output directly (for instance, &lt;a href=&quot;https://www.ncei.noaa.gov/thredds/dodsC/gfs-g4-anl-files/201901/20190126/gfsanl_4_20190126_0000_006.grb2.html&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; or &lt;a href=&quot;https://www.ncei.noaa.gov/thredds/catalog/gfs-g4-anl-files/201901/catalog.html&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;). Afterward, in post-processing the temperature is transformed to either Celsius or more commonly Fahrenheit for public consumption.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Scientists and meteorological researchers are more used to Kelvin and/or degrees Celsius. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorUserId="111" LastEditDate="2019-01-31T17:18:04.160" LastActivityDate="2019-01-31T17:18:04.160" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16118" PostTypeId="1" CreationDate="2019-01-31T12:33:42.257" Score="4" ViewCount="191" Body="&lt;p&gt;The &lt;a href=&quot;https://www.isws.illinois.edu/statecli/General/averages.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;State Climatologist Office for Illinois&lt;/a&gt; says the all time low temperature of Illinois was -36 °F, with a report of -37 °F in 2009 being disqualified.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This morning, the station &lt;a href=&quot;https://www.wunderground.com/personal-weather-station/dashboard?ID=KILOREGO7#history&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sinnissippi Point&lt;/a&gt; reported: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;6:00 AM -37.6 °F&lt;br&gt;&#xA;  6:15 AM -37.8 °F&lt;br&gt;&#xA;  6:30 AM -38.3 °F&lt;br&gt;&#xA;  6:45 AM -38.5 °F&lt;br&gt;&#xA;  7:00 AM -38.4 °F&lt;br&gt;&#xA;  7:15 AM -38.9 °F&lt;br&gt;&#xA;  7:30 AM -38.7 °F&lt;br&gt;&#xA;  7:45 AM &lt;strong&gt;-39 °F&lt;/strong&gt;&lt;br&gt;&#xA;  8:00 AM -37.7 °F  &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.wunderground.com/personal-weather-station/dashboard?ID=KILGALEN16#history/tdata/s20190131/e20190131/mdaily&quot; rel=&quot;nofollow noreferrer&quot;&gt;Galena&lt;/a&gt; was slightly lower reporting: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;6:48 AM -39 °F&lt;br&gt;&#xA;  6:53 AM -39 °F&lt;br&gt;&#xA;  6:59 AM -39.2 °F&lt;br&gt;&#xA;  7:04 AM -39 °F&lt;br&gt;&#xA;  7:09 AM -39.2 °F&lt;br&gt;&#xA;  7:14 AM -39 °F&lt;br&gt;&#xA;  7:19 AM -39 °F &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and other stations (such as &lt;a href=&quot;https://www.wunderground.com/personal-weather-station/dashboard?ID=KILSTOCK8&quot; rel=&quot;nofollow noreferrer&quot;&gt;North Fork Plum River&lt;/a&gt;: -36.8 °F; &lt;a href=&quot;https://www.wunderground.com/personal-weather-station/dashboard?ID=KILDURAN2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hawkeye Observatory&lt;/a&gt;: 37.4 °F) are reporting temperatures near -37 °F.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Was a new record set this day? Or is there some reason to disqualify or consider unofficial today's reports.  &lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="7314" LastEditDate="2019-02-01T16:03:52.430" LastActivityDate="2019-03-26T18:20:42.987" Title="Did temperature for the US state of Illinois reach an all-time record low 1/31/2019?" Tags="|meteorology|temperature|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16121" PostTypeId="2" ParentId="16115" CreationDate="2019-01-31T15:39:54.543" Score="15" Body="&lt;h1&gt;That device only shows Fahrenheit&lt;/h1&gt;&#xA;&lt;p&gt;I don't know about the full Weather Service, but that device only shows Fahrenheit measurements. You can see this in the &lt;a href=&quot;https://www.weather.gov/media/ind/nimbus_manual.pdf&quot; rel=&quot;noreferrer&quot;&gt;user manual&lt;/a&gt;, in the appendix, page 18&#xA;&lt;a href=&quot;https://i.stack.imgur.com/2oscM.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2oscM.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15065" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-01-31T18:22:33.773" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16122" PostTypeId="2" ParentId="16118" CreationDate="2019-01-31T16:48:01.277" Score="8" Body="&lt;p&gt;&lt;strong&gt;The record is unlikely to change, at least based on the particular measurements provided in the initial question.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the Illinois State Climatologist Office at the &lt;a href=&quot;https://www.isws.illinois.edu/statecli/General/averages.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;link you provided&lt;/a&gt;, the -37°F temperature record was discarded for lack of quality assurance: &quot;However, that observation came from a small airport station designed for aviation purposes and was not part of the climate network in Illinois. As a result, the data were not always archived and no quality control procedures were applied to the data.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the URLs in your question, the recent weather observations you refer to exist within &lt;a href=&quot;https://www.wunderground.com/weatherstation/overview.asp&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weather Underground's network of personal weather stations&lt;/a&gt;. In other words, they are often relatively inexpensive sensors that are owned and maintained by private individuals, and their measurements will not have the accuracy required to be included in the official temperature records for the state. The actual temperature at the Sinnissippi Point station may or may not have been colder than Illinois' verified lowest temperature, but without additional info (e.g. knowledge of specific instruments/sites and operator, as implied in the answer by @DavePhD) the official record will not change based on that measurement.&lt;/p&gt;&#xA;" OwnerUserId="14078" LastEditorUserId="14078" LastEditDate="2019-01-31T21:58:55.997" LastActivityDate="2019-01-31T21:58:55.997" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16124" PostTypeId="2" ParentId="16118" CreationDate="2019-01-31T18:04:10.883" Score="6" Body="&lt;p&gt;According to the &lt;a href=&quot;https://www.washingtonpost.com/weather/2019/01/31/brutal-cold-outbreak-is-breaking-records-midwest-thursday-morning/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Washington Post&lt;/a&gt;: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The cold snap is smashing all-time records in Northern Illinois. The state could have a new low temperature record as of Thursday morning, after Mount Carroll plummeted to minus-38 Thursday morning. The temperature was measured by a trained weather observer, according to the National Weather Service. The data will be examined by the Weather Service and the state climatologist to be certified as Illinois' lowest temperature. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;National Weather Service lists -38  °F as the low at Mount Carroll here: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://w2.weather.gov/climate/xmacis.php?wfo=dvn&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://w2.weather.gov/climate/xmacis.php?wfo=dvn&lt;/a&gt;  &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Carroll,_Illinois&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mount Carroll&lt;/a&gt; held the record from 1930 to 1999.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Update&lt;/strong&gt; from &lt;a href=&quot;https://stateclimatologist.web.illinois.edu/2019/03/06/il/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://stateclimatologist.web.illinois.edu/2019/03/06/il/&lt;/a&gt;:  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;After a comprehensive review, the State Climate Extremes Committee (SCEC) unanimously voted to validate the -38 degrees reading as the new official state record minimum temperature. This committee ensures that the observation is meteorologically plausible, is within a range that the reporting instrument can detect, and that the instrument is in proper working order.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="248" LastEditorUserId="248" LastEditDate="2019-03-26T18:20:42.987" LastActivityDate="2019-03-26T18:20:42.987" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="16125" PostTypeId="1" CreationDate="2019-01-31T18:41:57.963" Score="1" ViewCount="328" Body="&lt;p&gt;Does our current weather trend properly reflect a &lt;a href=&quot;https://en.wikipedia.org/wiki/Heinrich_event&quot; rel=&quot;nofollow noreferrer&quot;&gt;Heinrich Event&lt;/a&gt;?  It seems like the drastic weather swings are what I would expect but I realize that is not definitive.  I don't see the term bandied about as I would expect.  Are there other criteria missing? &lt;/p&gt;&#xA;" OwnerUserId="15066" LastEditorUserId="11908" LastEditDate="2019-04-06T20:04:09.217" LastActivityDate="2019-04-06T20:04:09.217" Title="Are we at the beginning of a Heinrich Event?" Tags="|geology|climate-change|glaciology|climate-models|glaciation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16127" PostTypeId="2" ParentId="16112" CreationDate="2019-01-31T20:04:02.920" Score="8" Body="&lt;p&gt;Yes. current climate change will most likely increase the amount of cultivable lands on Earth. However, it will at a high social cost and &lt;strong&gt;at the expense of biodiversity&lt;/strong&gt;, and I can't emphasize enough the paramount importance of biodiversity for the heath of ecosystems and human food safety.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider also that similarly to mining, where the value of a deposit is related not only to the total amount of mineral but also to its concentration, we have to consider also how intensive is the food production allowed by a piece of land. In this regard, climate change can lead to the loss of highly productive areas, compensated only by the gain of large expanses of nutrient poor soils in the tundra.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You should also consider the social impacts of the degradation of current cultivation lands and the economic costs of moving food production pole-wards.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer this question with some degree of certainty is extraordinarily complex, because we don't know how exactly climate will change, but several studies have addressed this problem. A good example is &lt;a href=&quot;https://onlinelibrary.wiley.com/doi/pdf/10.1046/j.1466-822x.2002.00294.x&quot; rel=&quot;noreferrer&quot;&gt;The global distribution of cultivable lands: current patterns and sensitivity to possible climate change&lt;/a&gt;. There they point that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We estimate that climate change, as simulated by global climate&#xA;  models, will expand cropland suitability by an additional 16%, mainly&#xA;  in the Northern Hemisphere high latitudes. However, the tropics&#xA;  (mainly Africa, northern South America, Mexico and Central America and&#xA;  Oceania) will experience a small decrease in suitability due to&#xA;  climate change.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Figure 4 of the paper shows the current &quot;land suitability index&quot; worldwide.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YmMgb.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YmMgb.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see how the north of America and Eurasia show large expanses (although quite exaggerated by the map projection) of land not suitable for cultivation due to the cold temperatures.&#xA;This data can be downloaded &lt;a href=&quot;https://nelson.wisc.edu/sage/data-and-models/atlas/maps.php?datasetid=19&amp;amp;includerelatedlinks=1&amp;amp;dataset=19&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;, and I've used it to plot the following figure that shows the mean cultivation suitability index as a function of latitude. It is also plotted the land area as a function of latitude as derived from &lt;a href=&quot;https://www.ngdc.noaa.gov/mgg/global/global.html&quot; rel=&quot;noreferrer&quot;&gt;ETOPO&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UkDPh.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UkDPh.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, pole-wards of 56° there is a significant amount of land of which none is suitable for cultivation. However, it is clear that temperature is not the whole picture, and aridity around 25° of latitude can significantly drop cultivation suitability.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found interesting to see that the left (equator-wards) side of the main peak in cultivation suitability currently at 37° lies at a latitude with a lot of land, so if that end is lost to aridity, the gain of land on its (right) pole-wards end will be smaller due to the downwards trends of land area towards the pole. Nevertheless, as I mentioned, models suggest climate change will increase the overall land surface suitable for agriculture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another study: &lt;a href=&quot;https://www.nature.com/articles/s41598-018-26321-8&quot; rel=&quot;noreferrer&quot;&gt;Northward shift of the agricultural climate zone under 21st-century global climate change&lt;/a&gt;. Focus on temperature and shows in Fig. 1 how the line that divides temperature regime suitable from cultivation of cereals will migrate northwards under the projected climate change:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gWVXQ.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gWVXQ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, they highlight the challenges for cultivation in high latitudes, which present a much more dramatic seasonal contrast that traditional crop lands:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;By 2099, roughly 76% of the boreal region might reach&#xA;  crop feasible conditions, compared to the current 32%. The leading&#xA;  edge of the feasible conditions will shift northwards. &lt;strong&gt;However, most of the&#xA;  newly gained areas are associated with highly seasonal and monthly&#xA;  variations in climatic water balances&lt;/strong&gt;, a critical component of any&#xA;  future land-use and management decisions.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;[the cite above was edited for simplification and context]&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-01-31T20:41:43.813" LastActivityDate="2019-01-31T20:41:43.813" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16129" PostTypeId="2" ParentId="16125" CreationDate="2019-01-31T20:23:42.190" Score="7" Body="&lt;p&gt;Definitely not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A &lt;a href=&quot;https://en.wikipedia.org/wiki/Heinrich_event&quot; rel=&quot;nofollow noreferrer&quot;&gt;Heinrich event&lt;/a&gt; requires massive ice sheets to grow and then collapse in the Northern hemisphere. The large outflow of icebergs that would result form such collapse would deliver fresh water and debris to the North Atlantic, which is what constitutes a Heinrich event. These events are detected by existence of deposits of &lt;a href=&quot;https://en.wikipedia.org/wiki/Ice_rafting&quot; rel=&quot;nofollow noreferrer&quot;&gt;ice rafted debris&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Dropstone&quot; rel=&quot;nofollow noreferrer&quot;&gt;dropstones&lt;/a&gt; in the sea floor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xV7tk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xV7tk.png&quot; alt=&quot;Image of rock from Namibia containing a penny-sized dropstone&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Example of a dropstone carried by an iceberg, dropped on the sea floor, and then embedded in sea floor sediments (image taken from &lt;a href=&quot;http://www.snowballearth.org/week1.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;snowballearth.com&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Current ice masses in the Northern hemisphere are tiny compared with those that generated all recorded Heinrich events.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Something similar could happen now further south if East Antarctica collapses. However the circulation pattern in the Antarctic ocean limit significantly the distance that icebergs can travel.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="239" LastEditDate="2019-02-01T15:53:46.210" LastActivityDate="2019-02-01T15:53:46.210" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16130" PostTypeId="1" CreationDate="2019-02-01T10:02:17.903" Score="1" ViewCount="38" Body="&lt;p&gt;I don't know if crystallography related topics go into this stack exchange, so sorry if that's wrong here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question concerns the characteristic shape of axial divergent powder patterns. According to Dinnerbier and Billinge, &lt;em&gt;Powder Diffraction Theory and Practice&lt;/em&gt;, RSC Publishing, &lt;strong&gt;2008&lt;/strong&gt; can an axially divergent reflection be decomposed into various positions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tuQQd.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tuQQd.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here &lt;em&gt;φ1&lt;/em&gt; marks the most divergent part of the incoming X-rays. What I can't find however is how this shape is related to the divergence itself. So why does it look like this 'fin' with a strong fronting-effect once the beam diverges? My idea would be the following. As the diffraction on the sample creates a scattering-cone where the circular base holds the information on the intensity we will only see some part of it, a conic section where the cone itersects with the detector slit. So the overall and still arbitrary intensity (y-axis, not area under the curve) should be the arc segment the slit actually detects. But if I move the detector slit (that is orthogonal to the cone's direction) parallel to this direction, so I intersect at a point closer or further away from the scattered sample I should expect the overall intensity in this arc segment to be smaller once it is further away as the same intensity should be spread over a larger circular path and therefore a segment has comparably lower intensity the further it is away from the source. That is at least how I would imagine it to happen.&#xA;So if some parts of the incoming beam scatter further away from the scattering center, so axial divergence happens the cone should travel a longer distance compared to the central part of the incoming X-rays (focus point). So if it intersects with the detector the main non-divergent part of the beam will have a smaller cone and higher intensity density than the divergent one. If both have a rather similar conic intersection (leaving curvature for a second) it should have a relatively lower intensity for the more divergent part of the beam.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is that reasoning somewhat logical or am I completely wrong here?&lt;/p&gt;&#xA;" OwnerUserId="15077" LastActivityDate="2019-02-01T10:02:17.903" Title="Crystallography: The shape of axial divergent profiles" Tags="|crystals|crystallography|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16132" PostTypeId="2" ParentId="15890" CreationDate="2019-02-01T18:43:34.153" Score="0" Body="&lt;p&gt;Having had some time to do some digging (hahaha), I have as close to an answer as I believe is possible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Small update just because: one of the smaller sinkholes has &lt;em&gt;dangerously&lt;/em&gt; grown, in a way that I wouldn't believe if I didn't see it.  It has widened slightly to about 45-60 cm, but grew &lt;strong&gt;substantially&lt;/strong&gt; deeper.  With a tape measure I clocked it in at 3.3m.  No joke.  It's pretty much a death trap to small animals or children.  I do not take my children back there anymore nor does anyone else seem to play there, fortunately.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Onto answering my question.  This is Florida, the land of sinkholes, and it seems that the assumption made by all parties involved is that this is an actual sink hole, and not some obscure side effect of the drainage area.  After querying my HOA I learned that the area is owned/managed by the local county government.  It doesn't sound like they bother doing geological studies (because sink holes are so common around here), but instead just fill sink holes in as they appear to avoid liability.  They are actually aware of the larger hole and put it on an &quot;official&quot; sink hole map (which will probably have a minor effect on my insurance rates).  They will also fill it in.  However, they are being quite slow about actually fixing it (which is a surprise because of the potential liability issues).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From what I have read on various government sites, sink holes around here are assumed to be fairly independent, i.e. a sink hole within 50 feet of your home doesn't imply that your house is any more likely to experience damage from a sink hole than any other house in the general area.  However, since the organization responsible for filling the hole is not going to be performing a geological survey, nor are they likely to bother consulting professionals, a best guess is the best I'm going to get.&lt;/p&gt;&#xA;" OwnerUserId="14511" LastActivityDate="2019-02-01T18:43:34.153" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16133" PostTypeId="2" ParentId="9488" CreationDate="2019-02-01T19:36:37.290" Score="13" Body="&lt;p&gt;It is not actual water what is lost to space, because in the high atmosphere water usually dissociate into other molecules or ions. The oxygen ion outflow is frequently assumed to be a proxy for the loss of water from the planetary atmosphere. In terms of global outflow rates for the Earth the rate varies from &lt;span class=&quot;math-container&quot;&gt;$10^{25}$&lt;/span&gt; to &lt;span class=&quot;math-container&quot;&gt;$10^{26} s^{-1}$&lt;/span&gt;, depending on geomagnetic activity (&lt;a href=&quot;https://ui.adsabs.harvard.edu//#abs/2017AGUFM.P11B2506S/abstract&quot; rel=&quot;noreferrer&quot;&gt;reference&lt;/a&gt;).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the poster of the reference (sent to me by the author) we can read:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If we assume oxygen corresponds to water loss (self-regulation, Hunten&#xA;  and McElroy [1970]), then an oxygen loss rate of ~&lt;span class=&quot;math-container&quot;&gt;$10^{25} s^{-1}$&lt;/span&gt;&#xA;  corresponds to ~300 &lt;span class=&quot;math-container&quot;&gt;$\text{g s}^{-1}$&lt;/span&gt; of water loss. Over the age of the&#xA;  solar system (4.5 billion years ~ &lt;span class=&quot;math-container&quot;&gt;$1.4 \times 10^{17}$&lt;/span&gt; s) this loss&#xA;  rate gives &lt;span class=&quot;math-container&quot;&gt;$4.2 \times 10^{19}$&lt;/span&gt; g of water.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The current loss figure is equivalent ~25,920 liters per day, or 9,467 &lt;span class=&quot;math-container&quot;&gt;$\text{m}^3$&lt;/span&gt; per year.&lt;/strong&gt; And the reference of that figure seem to be the paper &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2010GL045075&quot; rel=&quot;noreferrer&quot;&gt;Escape of O+ through the distant tail plasma sheet&lt;/a&gt;, that used measurements from the &lt;a href=&quot;https://en.wikipedia.org/wiki/STEREO&quot; rel=&quot;noreferrer&quot;&gt;STEREO‐B (Solar Terrestrial Relations Observatory) spacecraft&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;That would correspond to a total loss over Earth's history of 42,000 &lt;span class=&quot;math-container&quot;&gt;$\text{km}^3$&lt;/span&gt; of water, equivalent to about 12 cm of sea level change.&lt;/strong&gt; However, that's a straightforward extrapolation of the current rate, because they acknowledge that they don't know how to model how Earth's magnetosphere would have behaved in the past when the Sun was weaker. Although, for a weaker Sun it would be reasonable expect smaller losses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This value is radically different to that of &lt;a href=&quot;http://sciencenordic.com/earth-has-lost-quarter-its-water&quot; rel=&quot;noreferrer&quot;&gt;the article you pointed to&lt;/a&gt;. In that case they use the loss of hydrogen instead of oxygen as proxy for water loss:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Knowing how much hydrogen had disappeared from the oceans over the&#xA;  last four billion years enabled the researchers to calculate that the&#xA;  oceans have lost about a quarter of their water since the Earth’s&#xA;  early days.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They the say:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Today the atmosphere is rich in oxygen, which reacts with both&#xA;  hydrogen and deuterium to recreate water, which falls back to the&#xA;  Earth's surface. So the vast bulk of the water on Earth is held in a&#xA;  closed system that prevents the planet from gradually drying out.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That suggests that the limiting factor for the existence of water is now the abundance atmospheric oxygen (although oxygen in rocks if very abundant). So it would make sense to use now Oxygen loss as proxy for water loss, but in the past, before the atmosphere was flooded with oxygen, maybe hydrogen loss was a better proxy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They suggests that methanogenesis can free hydrogen atoms and make them liable to be loss to space, but when it is part of a water molecule it is safe. Methanogenesis would have been much more common in the past when the atmosphere was rich in methane (50 to 500 richer than today).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To wrap up, it seem that there is no consensus about the actual amount of water loss trough Earth's history. Different proxies give different values. Some proxies might be representative to some periods in Earth's past, but other proxies are more representative of other periods. And unfortunately we don't have yet a good reconstruction of the composition and density of the atmosphere throughout Earth's history.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But we do know with some confidence, that while you where reading this answer, one or two liters of water were loss to space.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-01T21:08:05.343" LastActivityDate="2019-02-01T21:08:05.343" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16135" PostTypeId="1" AcceptedAnswerId="16142" CreationDate="2019-02-01T20:39:35.867" Score="5" ViewCount="243" Body="&lt;p&gt;Given the current global CO2 emission trends, if the US overnight magically went to zero emissions (without affecting worldwide emissions), how many years until global CO2 emissions return to exactly where they are now.&lt;/p&gt;&#xA;" OwnerUserId="15084" LastActivityDate="2019-02-04T15:04:07.737" Title="If US emissions went to zero how long until global emissions reach current levels" Tags="|climate-change|climate|co2|emissions|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16138" PostTypeId="1" CreationDate="2019-02-02T06:47:09.887" Score="8" ViewCount="195" Body="&lt;p&gt;Refer to a report &lt;a href=&quot;https://www.theatlantic.com/science/archive/2019/01/polar-vortex-weather-forecasting-good-now/581605/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; that mentions the huge advancement in weather forecasting models since the 1980s:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How much better? “A modern five-day forecast is as accurate as a&#xA;  one-day forecast was in 1980,” says a new paper, published last week&#xA;  in the journal Science. “Useful forecasts now reach nine to 10 days&#xA;  into the future.”&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But weather forecasting cannot be indefinitely accurate, one fundamental limitation is Chaos Theory:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Chaos: When the present determines the future, but the approximate&#xA;  present does not approximately determine the future. (&lt;a href=&quot;https://en.wikipedia.org/wiki/Chaos_theory&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I used to think some ten or twenty years ago that the accuracy level of 3 day weather forecasts was due to Chaos Theory, but apparently it wasn't. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there studies where weather forecasting models are subjected to sensitivities of initial conditions, investigating how Chaos Theory puts an upper limit on the accuracies of such models? Also, based on current models, how much further can weather forecasting models go before the limits of Chaos Theory set in? &lt;/p&gt;&#xA;" OwnerUserId="2810" LastEditorUserId="2810" LastEditDate="2019-02-05T00:48:17.370" LastActivityDate="2019-02-05T00:48:17.370" Title="How much further can weather forecasting models go before the limits of Chaos Theory set in?" Tags="|meteorology|weather-forecasting|chaos|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="16139" PostTypeId="1" AcceptedAnswerId="16170" CreationDate="2019-02-02T09:05:25.637" Score="1" ViewCount="116" Body="&lt;p&gt;I am working on MOD10C2 (8days snow cover), when I clip the MODIS snow cover against different zones of elevation the results was against general trend .i.e. the higher elevation was showing lower snow cover and lower elevation was showing higher snow cover. I did the with matlab inpolygon function, (inpolygon(xq,yq,xv,yv)) I am could not figure out where I am making mistakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First of all I imported the data in this way&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;hdfvars =  {'Eight_Day_CMG_Snow_Cover', 'Eight_Day_CMG_Clear_Index',...&#xA;'Eight_Day_CMG_Cloud_Obscured', 'Snow_Spatial_QA'};&#xA; projectdir = 'E:\test\hdf test';&#xA;dinfo = dir( fullfile(projectdir, '*.hdf') );&#xA;num_files = length(dinfo);&#xA;filenames = fullfile( projectdir, {dinfo.name} );&#xA;Eight_Day_CMG_Snow_Cover = cell(num_files, 1);&#xA;Eight_Day_CMG_Clear_Index = cell(num_files, 1);&#xA;Eight_Day_CMG_Cloud_Obscured = cell(num_files, 1);&#xA;Snow_Spatial_QA = cell(num_files, 1);&#xA;for K = 1 : num_files&#xA; this_file = filenames{K};&#xA;Eight_Day_CMG_Snow_Cover{K} = hdfread(this_file, hdfvars{1});&#xA;Eight_Day_CMG_Clear_Index{K} = hdfread(this_file, hdfvars{2});&#xA;Eight_Day_CMG_Cloud_Obscured{K} = hdfread(this_file, hdfvars{3});&#xA;  Snow_Spatial_QA{K} = hdfread(this_file, hdfvars{4});&#xA;end&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Then reshaped data in this way&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;B2 = zeros(3600,7200,24);&#xA;for i = 1:3600&#xA;for j = 1:7200&#xA;B2(i,j,1:24) = reshape(Eight_Day_CMG_Snow_Cover{i,j},[1 3 2]);&#xA;end&#xA;end&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Then generate lat lon and subset the area of interest&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;lon = -180:0.05:180;&#xA;lat = -90:0.05:90;&#xA;subsetqa = Eight_Day_CMG_Snow_Cover(2001:2817,4801:5741,:);&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;then attempted to extract with elevation polygon,&#xA;I tried both [monthly] and [8days] fractional snow cover data, elevation polygon are extracted from SRTM DEM. I attempted to use matlab in this way&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;shapefile = 'shapefile.shp' ;&#xA;S = shaperead(shapefile) ;&#xA;&#xA;N = length(S) ;&#xA;for i = 1:N&#xA;    plot(S(i).X,S(i).Y)&#xA;    hold on&#xA;end&#xA;%%&#xA;lon = load('testlon.mat') ; lon = lon.testlon ;&#xA;lat = load('testlat.mat') ; lat = lat.testlat ;&#xA;&#xA;[X,Y] = meshgrid(lon,lat) ;&#xA;&#xA;data = load('testarray.mat') ; data = data.testarray ;&#xA;[nx,ny,d] = size(data) ;&#xA;&#xA;%%Extract data &#xA;iwant = cell(d,N) ;&#xA;for i =1:d&#xA;    A = data(:,:,i) ;&#xA;    for j = 1:N&#xA;        idx = inpolygon(X(:),Y(:),S(i).X,S(i).Y) ;&#xA;        iwant{i,j} = A(idx) ;&#xA;    end&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Then output iwant converted into matrix in this way&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;test = cell2mat(cellfun(@transpose,iwant,'uniform',0));&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;NOTE: this picture is showing polygon of only one elevation zone and we have six different elevation zones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UOCLB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UOCLB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12714" LastEditorUserId="11908" LastEditDate="2019-02-06T15:53:14.573" LastActivityDate="2019-02-06T15:53:14.573" Title="How to figure the MODIS snow cover against different elevation zones?" Tags="|mountains|remote-sensing|snow|gis|" AnswerCount="1" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="16140" PostTypeId="1" AcceptedAnswerId="16141" CreationDate="2019-02-02T16:55:23.057" Score="6" ViewCount="168" Body="&lt;p&gt;Avery Thompson &lt;a href=&quot;https://www.popularmechanics.com/science/environment/a26092076/nasa-found-a-giant-underground-cavern-in-antarctica-almost-the-size-of-manhattan/&quot; rel=&quot;noreferrer&quot;&gt;writes in Popular Mechanics&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In Thwaites’ case, that radar uncovered a gigantic cavern between the glacier itself and the bedrock below it. That cavern is likely filled with air much warmer than the surrounding ice, triggering faster melting of the glacier than would happen otherwise.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;From the &lt;a href=&quot;https://www.nasa.gov/feature/jpl/huge-cavity-in-antarctic-glacier-signals-rapid-decay&quot; rel=&quot;noreferrer&quot;&gt;cited NASA release&lt;/a&gt; I would have assumed that the cavity is full of water (if only because ice is not strong enough to support such a large air-filled cavern).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is it air or water?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="11908" LastEditDate="2019-03-13T05:00:59.970" LastActivityDate="2019-03-13T05:00:59.970" Title="Giant Cavern the Size of Manhattan Under Thwaites Glacier in West Antarctica" Tags="|glaciology|antarctica|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16141" PostTypeId="2" ParentId="16140" CreationDate="2019-02-02T17:18:18.670" Score="6" Body="&lt;p&gt;The cave is created by warm water, so the ice has been replaced by the water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is common to find areas under the front of glaciers that have been melted away by warm water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Warm water here means just warmer than the ice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The thing that's making this news is the scale of the area that has melted away.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the situation scientists have been predicting to happen as our planet warms, water advancing inland below the ice and possibly making the glacier move faster.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ice that is connected to bedrock will create friction making the ice move at a slower pace. When ice is no longer connected to the bedrock under it will loose this friction and possibly speed up the flow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This might be one of the tipping points making the ice melt at a faster pace.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Thwaites_Glacier&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Thwaites_Glacier&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As fred say in his comment ice moving over bedrock will create friction this friction will create a layer of liquid water lubricating the ice and make the ice flow faster,And when ice melts at the surface of the ice the melt water will run down cracks in the ice and reach the bedrock lowering the friction even more.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6258" LastEditDate="2019-02-03T05:33:50.847" LastActivityDate="2019-02-03T05:33:50.847" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16142" PostTypeId="2" ParentId="16135" CreationDate="2019-02-02T17:37:16.497" Score="4" Body="&lt;p&gt;That will depend on the emission scenario you pick for the future, the more recent scenarios are the &lt;a href=&quot;https://en.wikipedia.org/wiki/Representative_Concentration_Pathways&quot; rel=&quot;nofollow noreferrer&quot;&gt;RCP&lt;/a&gt;'s (Representative Concentration Pathway).&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;RCP scenarios&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The scenarios involve future pathways in the emissions of a large range of different chemicals (Greenhouse gases and aerosols). Each RCP have a temperature tag, for example RCP6.0, is a scenario that consider many geopolitical, social and economical predictions and that would result in an emission pathway that would the radiative forcing (input energy to Earth) by 6.0 W/m&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt; by year 2100.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data associated with the RCPs can be accessed in the &lt;a href=&quot;https://tntcat.iiasa.ac.at/RcpDb/dsd?Action=htmlpage&amp;amp;page=compare&quot; rel=&quot;nofollow noreferrer&quot;&gt;RCP Database&lt;/a&gt;, this is a plot generated there with Global &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; emissions for all four RCP scenarios.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/a7f1I.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/a7f1I.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_countries_by_carbon_dioxide_emissions&quot; rel=&quot;nofollow noreferrer&quot;&gt;this data&lt;/a&gt;, the U.S. was responsible for 14.34% of the global emissions of &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; on 2015.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we consider that overnight all scenarios switch to a  version of themselves with a 14.34% emissions reductions (i.e. like if the US stopped all its emissions suddenly), the plot would look like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zM0Ma.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zM0Ma.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where the dashed line is the new emission pathway and the thin dotted line marks the global emission level before the US &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; shutdown.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;We can see that for RCP2.6 and RCP4.5, the world would never get back to emission rates as high as those of today. And for the more pessimistic scenarios it would take at least 10 years to go back to those levels: For RCP6.0 it would go back to current levels by 2041 and for RCP8.5 by 2029.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are many simplifications on this calculation, but gives you a first approach. If you are interested in another emission scenario you can apply the same methodology or a better one, but maybe this can serve as a starting pint.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-04T15:04:07.737" LastActivityDate="2019-02-04T15:04:07.737" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16144" PostTypeId="2" ParentId="16138" CreationDate="2019-02-03T18:15:25.423" Score="1" Body="&lt;p&gt;There are (at least) two factors involved here, before we even get to questions of chaos theory.  First, thanks to weather satellites and other sensor improvements,  we can measure the initial conditions much more accurately.  (One can do a halfway decent 3-day forecast for the West Coast just by eyeballing the GOES West images.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second, we have greatly increased computing power.  Forecast models (simplisticaly) work by dividing the world, or part of it, into a 3D grid, applying a set of differential equations in the grid, propagating the changes to neighbors, and then stepping forward in time to repeat the process. The finer you can make the grid, the more accurate the forecast can be.  However, if you cut the size of a cell in half, you need to do 8 times as much computing.  And if it takes longer to do your computation than the actual weather, it's not much use as a forecast :-)&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2019-02-03T18:15:25.423" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="16145" PostTypeId="5" CreationDate="2019-02-03T19:06:32.180" Score="0" Body="&lt;p&gt;Earth Sciences require the acquisition of vast amount of field measurements, such as temperature, topography, chemical composition, optical properties, etc. &#xA;This tag is related to anything related to the acquisition, processing and interpretation of such measurements.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-03T19:06:32.180" LastActivityDate="2019-02-03T19:06:32.180" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16146" PostTypeId="4" CreationDate="2019-02-03T19:06:32.180" Score="0" Body="Questions related to acquiring, processing and interpreting field measurements of any kind. Including instrumentation and data analysis." OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-03T19:06:32.180" LastActivityDate="2019-02-03T19:06:32.180" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16147" PostTypeId="5" CreationDate="2019-02-03T19:20:23.320" Score="0" Body="&lt;p&gt;An &lt;a href=&quot;https://en.wikipedia.org/wiki/Ice_shelf&quot; rel=&quot;nofollow noreferrer&quot;&gt;ice shelf&lt;/a&gt; is a thick suspended platform of ice that forms where a glacier or ice sheet flows down to the shore and onto the ocean. Ice shelves are only found in Antarctica, Greenland, Canada, and the Russian Arctic. &lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-03T19:20:23.320" LastActivityDate="2019-02-03T19:20:23.320" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16148" PostTypeId="4" CreationDate="2019-02-03T19:20:23.320" Score="0" Body="Ice shelves are thick floating platforms of glacier ice. Not grounded ice (glaciers and snow) or sea ice (frozen sea water)." OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-03T19:20:23.320" LastActivityDate="2019-02-03T19:20:23.320" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16149" PostTypeId="5" CreationDate="2019-02-03T19:31:35.360" Score="0" Body="&lt;p&gt;A glaciation (or &lt;a href=&quot;https://en.wikipedia.org/wiki/Glacial_period&quot; rel=&quot;nofollow noreferrer&quot;&gt;glacial period&lt;/a&gt;) is an interval of time (thousands of years) within an ice age that is marked by colder temperatures and glacier advances. Interglacials, on the other hand, are periods of warmer climate between glacial periods. The last glacial period ended about 15,000 years ago. The Holocene epoch is the current interglacial.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, glaciation in a more broad sense can be used also to describe ice ages as a whole.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-03T19:31:35.360" LastActivityDate="2019-02-03T19:31:35.360" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16150" PostTypeId="4" CreationDate="2019-02-03T19:31:35.360" Score="0" Body="Questions about glaciations, glacial periods or ice ages. Including the evidence of their existence, the conditions during such periods and the causes." OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-03T19:31:35.360" LastActivityDate="2019-02-03T19:31:35.360" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16151" PostTypeId="5" CreationDate="2019-02-03T19:46:52.180" Score="0" Body="&lt;p&gt;Astronomy deals with the workings of anything beyond the limits of the Earth. The main intersections with Earth Sciences are solar system formation, planetary sciences, orbital controls on the Earth and the effects of the Sun and its evolution on Earth's history.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-03T19:46:52.180" LastActivityDate="2019-02-03T19:46:52.180" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16152" PostTypeId="4" CreationDate="2019-02-03T19:46:52.180" Score="0" Body="Questions that intersects astronomy with Earth Sciences. For pure astronomy please refer to the Astronomy Stack Exchange." OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-03T19:46:52.180" LastActivityDate="2019-02-03T19:46:52.180" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16153" PostTypeId="5" CreationDate="2019-02-03T19:49:16.063" Score="0" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Cryosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;cryosphere&lt;/a&gt; refers to those portions of Earth's surface where water is in solid form, including sea ice, lake ice, river ice, snow cover, glaciers, ice caps, ice sheets, and frozen ground (which includes permafrost).&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-03T19:49:16.063" LastActivityDate="2019-02-03T19:49:16.063" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16154" PostTypeId="4" CreationDate="2019-02-03T19:49:16.063" Score="0" Body="Questions regarding the area of the Earth where water is in solid form, including sea ice, lake ice, river ice, snow cover, glaciers, ice caps, ice sheets, and permafrost." OwnerUserId="11908" LastEditorUserId="6298" LastEditDate="2019-02-06T02:49:36.567" LastActivityDate="2019-02-06T02:49:36.567" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16155" PostTypeId="5" CreationDate="2019-02-03T19:52:13.173" Score="0" Body="&lt;p&gt;Tag associated to questions related to projects to build custom solutions to Earth Science problems, such ad instruments, sensors, data loggers, tests, etc.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-03T19:52:13.173" LastActivityDate="2019-02-03T19:52:13.173" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16156" PostTypeId="4" CreationDate="2019-02-03T19:52:13.173" Score="0" Body="Do-It-Yourself, any questions regarding custom made instruments, sensors or solutions for Earth Sciences related problems." OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-03T19:52:13.173" LastActivityDate="2019-02-03T19:52:13.173" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16157" PostTypeId="1" CreationDate="2019-02-03T20:06:41.917" Score="4" ViewCount="116" Body="&lt;p&gt;Is there consensus amongst climatologists that cold weather extremes are caused by global warming or human influence?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hear the claim a lot that the recent cold weather extremes (such as the polar vortex affecting the US) are caused by global warming, but haven't seen many scientific papers supporting it. I'm not sure if I just haven't come across more. And, I'm not sure if the ones that exist are even considered compelling by climatologists. &lt;/p&gt;&#xA;" OwnerUserId="15093" LastEditorUserId="15093" LastEditDate="2019-02-03T20:53:28.043" LastActivityDate="2019-02-03T21:24:31.230" Title="Is there consensus amongst climatologists that cold weather extremes are caused by global warming or human influence?" Tags="|climate-change|climate|climatology|extreme-weather|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16158" PostTypeId="2" ParentId="16157" CreationDate="2019-02-03T21:24:31.230" Score="1" Body="&lt;p&gt;It is common sense. The more energy in the Atmosphere the most intense will be the stirring up of it, so you will get cold polar air and hot tropical air moving around further and producing extreme weather.&lt;/p&gt;&#xA;" OwnerUserId="15095" LastActivityDate="2019-02-03T21:24:31.230" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16159" PostTypeId="1" AcceptedAnswerId="16189" CreationDate="2019-02-04T01:14:17.900" Score="1" ViewCount="328" Body="&lt;p&gt;I am writing a space colonization game, and I need some guidance on default values for mine productivity. If you also know an estimate of how much people work on them, that's a bonus. Thanks in advance :)&lt;/p&gt;&#xA;" OwnerUserId="11401" LastEditorUserId="725" LastEditDate="2019-02-06T22:52:58.747" LastActivityDate="2019-02-06T22:52:58.747" Title="How many mines are there on Earth, and what is their output in tonnes?" Tags="|economic-geology|mining|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16160" PostTypeId="1" AcceptedAnswerId="16161" CreationDate="2019-02-04T02:21:06.700" Score="4" ViewCount="105" Body="&lt;p&gt;This is a follow-up question to &lt;a href=&quot;https://earthscience.stackexchange.com/q/16140/6031&quot;&gt;Giant Cavern the Size of Manhattan Under Thwaites Glacier in West Antarctica&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The work is reported in an &lt;strong&gt;open access paper&lt;/strong&gt; in Science: &lt;a href=&quot;http://advances.sciencemag.org/content/5/1/eaau3433&quot; rel=&quot;nofollow noreferrer&quot;&gt;Heterogeneous retreat and ice melt of Thwaites Glacier, West Antarctica&lt;/a&gt; which is very technical, thorough, and hard for me to understand.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The work is based on a substantial amount of radar data, both SAR (Synthetic Aperture Radar) from several satellites, and (from Pasadena Now) &lt;a href=&quot;http://www.pasadenanow.com/main/pasadena-scientists-find-report-disturbing-find/&quot; rel=&quot;nofollow noreferrer&quot;&gt;...by ice-penetrating radar in NASA’s Operation IceBridge, an airborne campaign that began in 2010 and studies connections between the polar regions and the global climate.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it possible to explain the differences between the two kinds of radar data (space and airborne) and how they were combined and used together to establish the size/volume and growth of this unexpectedly large amount of liquid water below the glacier? &lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="11908" LastEditDate="2019-04-06T22:31:31.773" LastActivityDate="2019-04-06T22:31:31.773" Title="Giant Cavern the Size of Manhattan Under Thwaites Glacier in West Antarctica - how was satellite and airborne radar data combined?" Tags="|glaciology|satellites|radar|antarctica|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="16161" PostTypeId="2" ParentId="16160" CreationDate="2019-02-04T05:40:59.233" Score="4" Body="&lt;p&gt;The paper basically combines multiple datasets to figure out the changes in ice surface elevation and ice thickness at tidal and multi-year timescales. That way they were able to study grounding line migration, and the melt rate of the glacier and its corresponding ice shelf from above and below. Then they were able to make inferences of the processes producing glacier melting, specially basal melting that is difficult to measure directly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They actually used three datasets:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;DInSAR&lt;/strong&gt;: Standing for Differential Interferometric Synthetic Aperture Radar. It is basically a technique that compares the phase of two SAR images acquired at different time to compute uplift/subsidence of the surface with great accuracy (usually millimeters). So they were able to see the surface of the ice shelf rise and lower with the tides, and also compute surface flow velocities.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;IceBridge MCoRDS&lt;/strong&gt;: Airborne radar depth sounder MCoRDS (Multichannel Coherent Radar Depth Sounder) operated by NASA mission IceBridge. This is a much more powerful radar operated close to the surface and designed to penetrate the ice, allowing to see the bedrock topography beneath the ice and some of the structure above the bedrock, such as water/ice transitions or layers of ice with distinct dielectric properties. This allowed them to know the ice thickness and bedrock topography.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;TDX DEM&lt;/strong&gt;: TanDEM-X Digital Elevation Model. This are Surface topography models generated using single pass InSAR data provided by two SAR satellites that orbit in tandem formation (one immediately behind the other). This allows precise surface topography measurements, that are also needed for the DInSAR processing.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I hope that helps. It is a very interesting work. Although the &quot;giant cavern&quot; part is not the most relevant part of it at all, but it was great for catchy headlines.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-02-04T05:40:59.233" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16163" PostTypeId="1" AcceptedAnswerId="16166" CreationDate="2019-02-04T12:36:52.357" Score="8" ViewCount="235" Body="&lt;p&gt;According to this article &lt;a href=&quot;https://www.csmonitor.com/Environment/Energy-Voices/2014/0714/How-long-will-world-s-oil-reserves-last-53-years-says-BP&quot; rel=&quot;noreferrer&quot;&gt;How long will world's oil reserves last?&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;At the current rate of extraction oil reserves will last 53 years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And according to this another article, &lt;a href=&quot;https://climate.nasa.gov/vital-signs/global-temperature/&quot; rel=&quot;noreferrer&quot;&gt;Global temperature - NASA&lt;/a&gt;, global temperature increased about a Celsius degree in 80 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suppose we can't directly extrapolate the years because I assume oil's consumption is higher now than before, but is it possible to estimate how much Earth's temperature could increase by the time we run out of oil reserves? Wouldn't it be about a degree or something like happened in the previous 80 years? Is that a problem to really be worried about?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastEditorUserId="6298" LastEditDate="2019-02-06T00:39:47.947" LastActivityDate="2019-02-06T00:39:47.947" Title="How much could Earth's temperature increase by the time we run out of oil reserves?" Tags="|climate-change|temperature|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16164" PostTypeId="1" CreationDate="2019-02-04T14:22:40.883" Score="15" ViewCount="10706" Body="&lt;p&gt;On Earth, there is enough Hydrogen and Oxygen to make 13,88 million km&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt; of water (calculation below). However, oceans contain &lt;a href=&quot;https://en.wikipedia.org/wiki/Water_distribution_on_Earth&quot; rel=&quot;noreferrer&quot;&gt;only a tenth of that&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clearly, most of the hydrogen must be stored in other chemical compounds different to water. Or, as water deep within Earth's interior: &lt;a href=&quot;https://www.theguardian.com/science/2014/jun/13/earth-may-have-underground-ocean-three-times-that-on-surface&quot; rel=&quot;noreferrer&quot;&gt;some studies suggest the water on Earth's interior could contain three times as much as the water near the surface&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand there are many chemical reactions, like the well known &lt;a href=&quot;https://en.wikipedia.org/wiki/Photosynthesis&quot; rel=&quot;noreferrer&quot;&gt;photosynthesis&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Cellular_respiration&quot; rel=&quot;noreferrer&quot;&gt;respiration&lt;/a&gt;, that can transform water into other compounds and vice versa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We often think that there is a fixed amount of liquid water on Earth (plus or minus what is being recycled in the atmosphere). But it seems to me that the processes above could change the water amount significantly over geological timescales.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my question could be stated as follows: &lt;strong&gt;over geological timescales, what determines the amount of liquid water on Earth?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are two examples of the processes I'm thinking about:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Reservoir transfers&lt;/strong&gt;: If water from a well is removed, the ground water reservoir around it will slowly re-fill the well. Would the same happen with Earth's oceans if removed? Would water from the deep Earth's interior partially re-fill the oceans through volcanic eruptions?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Chemical balance&lt;/strong&gt;: For a chemical reaction that can go both ways, if the reactants and products are in equilibrium and I remove the product compounds, more of them will be generated until a new equilibrium is reached. Would the same happen if I remove the water from Earth's surface? Will Hydrogen and Oxygen from rocks and air combine to partially replenish the oceans?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(This question was inspired by &lt;a href=&quot;https://earthscience.stackexchange.com/q/9488/11908&quot;&gt;How much water is the atmosphere losing to space?&lt;/a&gt;)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Calculation of the maximum possible water on Earth&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The maximum amount of water you can have on Earth is limited by the available hydrogen. Now, for each gram of bulk Earth there are &lt;a href=&quot;https://web.archive.org/web/20110928074153/http://quake.mit.edu/hilstgroup/CoreMantle/EarthCompo.pdf&quot; rel=&quot;noreferrer&quot;&gt;260 &lt;span class=&quot;math-container&quot;&gt;$\mu\text{g}$&lt;/span&gt; of hydrogen&lt;/a&gt; and plenty of Oxygen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given that the &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth&quot; rel=&quot;noreferrer&quot;&gt;Earth's mass is &lt;span class=&quot;math-container&quot;&gt;$5.972 \times 10^{27}$&lt;/span&gt;&lt;/a&gt;, and 260 &lt;span class=&quot;math-container&quot;&gt;$\mu\text{g/g}$&lt;/span&gt; correspond to Hydrogen, that would total &lt;span class=&quot;math-container&quot;&gt;$1.552 \times 10^{24}$&lt;/span&gt; g of Hydrogen, that at a &lt;a href=&quot;http://ciaaw.org/hydrogen.htm&quot; rel=&quot;noreferrer&quot;&gt;molar mass of 1.007 g/mol&lt;/a&gt;, corresponds to &lt;span class=&quot;math-container&quot;&gt;$1.540 \times 10^{24}$&lt;/span&gt; mol, enough to make &lt;span class=&quot;math-container&quot;&gt;$7.703 \times 10^{23}$&lt;/span&gt; mol of water (as two atoms of hydrogen are required in a molecule of water). And since water has a molecular mass of &lt;a href=&quot;https://en.wikipedia.org/wiki/Properties_of_water&quot; rel=&quot;noreferrer&quot;&gt;18.0152 g/mol&lt;/a&gt;, such an amount of water would weigh &lt;span class=&quot;math-container&quot;&gt;$1.3877\times 10^{25}$&lt;/span&gt; grams. Finally, assuming a density of 1 &lt;span class=&quot;math-container&quot;&gt;$\text{g/cm}^3$&lt;/span&gt; we get a total of &lt;span class=&quot;math-container&quot;&gt;$1.3877\times 10^{25}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\text{cm}^3$&lt;/span&gt; or &lt;span class=&quot;math-container&quot;&gt;$13,877,025,731\, \text{km}^3$&lt;/span&gt;; that &lt;strong&gt;corresponds to 10.01 times the amount of water near Earth's surface&lt;/strong&gt; (including oceans, lakes, rivers, ground water, etc.) and that is estimated to add up to &lt;a href=&quot;https://en.wikipedia.org/wiki/Water_distribution_on_Earth&quot; rel=&quot;noreferrer&quot;&gt;1,386,000,000 &lt;span class=&quot;math-container&quot;&gt;$\text{km}^3$&lt;/span&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-03-11T20:57:40.597" LastActivityDate="2019-03-11T20:57:40.597" Title="Would oceans regenerate if removed?" Tags="|geology|geophysics|oceanography|geochemistry|water|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16165" PostTypeId="2" ParentId="16164" CreationDate="2019-02-04T14:22:40.883" Score="10" Body="&lt;p&gt;I'm ignorant of all the organic and inorganic chemical reactions that can destroy or create water, and the factors controlling them. But I can give a shot to the part of the question related to volcanoes and the water stored on Earth's interior:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most abundant gas in volcanic eruptions is water, corresponding to more than the 80% of emitted gases in volume (&lt;a href=&quot;https://www.nat-hazards-earth-syst-sci.net/2/91/2002/nhess-2-91-2002.pdf&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;).&#xA;If we consider on of the largest volcanic eruptions we know about: The &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Toba&quot; rel=&quot;noreferrer&quot;&gt;toba supervolcano eruption&lt;/a&gt; 75,000 years ago. The water volume emitted &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/96GL02088&quot; rel=&quot;noreferrer&quot;&gt;has been estimated in &lt;span class=&quot;math-container&quot;&gt;$540\, \text{km}^3$&lt;/span&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nvRKI.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nvRKI.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Figure: Comparison of ejected material from notable eruptions (&lt;a href=&quot;https://www.npr.org/sections/krulwich/2012/10/22/163397584/how-human-beings-almost-vanished-from-earth-in-70-000-b-c&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From that perspective, you can see that you would need about 2.5 million Toba eruptions to re-fill the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the past, over the history of Earth it could be reasonable to think that the volcanic output could average to the equivalent one Toba eruption every 2000 years, something that would be enough to deliver the volume of water currently in the oceans, but over 4.5 billion years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, most volcanic activity on Earth is related to subduction volcanism (including Toba), and such volcanism relies on water input to produce the erupting magmas, and arguably, a large fraction of the erupted water is the same water that was lost in the corresponding subduction zone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can then conclude that volcanic water input could eventually help keeping the level on a drying ocean, but at a very slow rate and over very long timescales. But if the oceans ever go dry, volcanism is unlikely to revert the situation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the context of the question that motivated this one, the rate at which volcanoes release water dwarf that of water losses to space. However, over long enough times those losses could dry our both the ocean and the Earth interior. But more importantly, I don't know if the net transfer of water from/to the Earth's interior is zero (in balance) or if the mantle is actually sucking water from the oceans, or filling them up. It might be that instead of worrying of planets loosing their water to space, we should worry about them loosing it to their guts.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-02-04T14:22:40.883" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16166" PostTypeId="2" ParentId="16163" CreationDate="2019-02-04T15:50:10.747" Score="7" Body="&lt;p&gt;That estimation is based on current extraction rates and based in 2013, so we would have oil reserves until 2066.&#xA;Assuming that's correct, it would resemble the &quot;business as usual&quot; future emissions scenario, a.k.a. RCP8.5 (&lt;a href=&quot;https://en.wikipedia.org/wiki/Representative_Concentration_Pathway&quot; rel=&quot;nofollow noreferrer&quot;&gt;more about RPCs&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the last &lt;a href=&quot;https://www.ipcc.ch/reports/&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC report&lt;/a&gt;, the range of mean global temperature predictions for RCP8.5 looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6H9KF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6H9KF.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We are now 0.5°C above the figure's baseline, and in the next 80 years, which is about year 2100 the temperature would be about 3.5°C above current temperature. But the range spanned by different predictions goes from 3°C to 5.5°C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that the warming effect of putting additional &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; in the atmosphere last many centuries, so even if emissions stop suddenly bu year 2066, the planet will keep getting hotter and hotter for a long time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also note that the warming is not homogeneous, some areas will warm much more than others, in RCP8.5 scenario many areas would warm by more than 6°C, &lt;a href=&quot;https://sos.noaa.gov/Datasets/view-movie.html?video=rcp_ga_85_400&quot; rel=&quot;nofollow noreferrer&quot;&gt;this animation by NOAA&lt;/a&gt; gives you a nice idea of the rate and pattern of warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And regarding your question:  Is that a problem to really be worried about? the answer is definitely YES! The RCP8.5 scenario is the most pessimistic one, if that one realizes we will be in a lot of trouble, dealing with climate change, weather extremes, sea level rise and massive migrations.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-05T19:53:22.137" LastActivityDate="2019-02-05T19:53:22.137" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16167" PostTypeId="1" AcceptedAnswerId="16185" CreationDate="2019-02-04T15:56:23.937" Score="4" ViewCount="104" Body="&lt;p&gt;So I tried to calculate the rise of waterlevel myself. But the results I have gotten seem to be pretty low:&lt;a href=&quot;https://i.stack.imgur.com/MaubK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MaubK.png&quot; alt=&quot;Waterlevel increase for different events&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given the earths radius, I clalculated different Events:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) If all landice melts there is an increase of the earths radius of ~54m. This number should be a bit higher because only ~70% of earths surface is water. For the ice I also didn't took the change of density into account because its relatively negligible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Then I calculated the new radius given the annual loss of ice 2011-2014. This number was surprisingly low with only ~1mm each year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) And for the extreme increase of water temperature globally of 9°C I took the Global Water Volume into account. But the increase of 5.2m is not that big either.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So are my numbers as expected or did I do something wrong? Because these numbers don't explain the predicted massive increase of the sea level in the near future.&lt;/p&gt;&#xA;" OwnerUserId="15098" LastActivityDate="2019-02-06T16:24:39.997" Title="Waterlevel increase calculation" Tags="|climate-change|sea-level|glaciology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16168" PostTypeId="2" ParentId="16164" CreationDate="2019-02-04T16:49:54.400" Score="2" Body="&lt;p&gt;Photosynthesis and respiration only exchange water for organic compounds and vice versa, those reactions can not alter the amount of water in the earth, only convert a small part into organic compounds.&lt;/p&gt;&#xA;" OwnerUserId="15099" LastActivityDate="2019-02-04T16:49:54.400" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16170" PostTypeId="2" ParentId="16139" CreationDate="2019-02-04T17:46:51.500" Score="2" Body="&lt;p&gt;The problem (if there is only one) is in the way you are importing the data into .mat file. If with the files you provided I do&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;data = load('sc_8days.mat') ;&#xA;data = data.sc8days ;&#xA;[nx,ny,d] = size(data) ;&#xA;imagesc(data(:,:,1));&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;I get this nonsense:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8M5kw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8M5kw.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and d=23, while the MOD10C2 data has only four bands: Eight_Day_CMG_Snow_Cover, Eight_Day_CMG_Cloud_Obscured, Eight_Day_CMG_Clear_Index, and Snow_Spatial_QA (see &lt;a href=&quot;https://nsidc.org/data/mod10c2&quot; rel=&quot;nofollow noreferrer&quot;&gt;product specifications&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, if I load the data and plot directly from the .hdf file you shared, with&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;data = hdfread('MOD10C2.A2000185.006.2016068190452.hdf','Eight_Day_CMG_Snow_Cover');&#xA;imagesc(data);&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;I get:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ck4xl.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ck4xl.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which does makes sense and show the actual data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, the way you are importing the data into your .mat file is messing things up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The error is in this line&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;B2(i,j,1:24) = reshape(Eight_Day_CMG_Snow_Cover{i,j},[1 3 2]);&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Because you are assigning the pixel i,j of each file using data from one file only, and also that should generate and error, I'm not quite sure how this code can run, as the size of Eight_Day_CMG_Snow_Cover is Kx1 and you are attempting to access elements i,j.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyway, that way is too cumbersome, avoid reshaping and using cell arrays by importing like this:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;hdfvars =  {'Eight_Day_CMG_Snow_Cover', 'Eight_Day_CMG_Clear_Index',...&#xA;'Eight_Day_CMG_Cloud_Obscured', 'Snow_Spatial_QA'};&#xA;projectdir = 'E:\test\hdf test';&#xA;dinfo = dir( fullfile(projectdir, '*.hdf'));&#xA;num_files = length(dinfo);&#xA;filenames = fullfile(projectdir,{dinfo.name});&#xA;&#xA;Eight_Day_CMG_Snow_Cover = zeros(3600,7200,num_files);&#xA;Eight_Day_CMG_Clear_Index = zeros(3600,7200,num_files);&#xA;Eight_Day_CMG_Cloud_Obscured = zeros(3600,7200,num_files);&#xA;Snow_Spatial_QA = zeros(3600,7200,num_files);&#xA;&#xA;for K = 1 : num_files&#xA;    this_file = filenames{K};&#xA;    Eight_Day_CMG_Snow_Cover(:,:,K) = hdfread(this_file, hdfvars{1});&#xA;    Eight_Day_CMG_Clear_Index(:,:,K) = hdfread(this_file, hdfvars{2});&#xA;    Eight_Day_CMG_Cloud_Obscured(:,:,K) = hdfread(this_file, hdfvars{3});&#xA;    Snow_Spatial_QA(:,:,K) = hdfread(this_file, hdfvars{4});&#xA;end&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;So in this case, the variable Eight_Day_CMG_Snow_Cover contains what you wanted to put in B2.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-05T19:17:21.467" LastActivityDate="2019-02-05T19:17:21.467" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16171" PostTypeId="1" CreationDate="2019-02-04T18:41:25.977" Score="3" ViewCount="438" Body="&lt;p&gt;A group of students and I have gone to a field trip where we performed tasks like: measuring the velocity of the river flow, finding the width and depth to produce a cross section along with valley profile and gradient.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am a bit confused though regarding bedload analysis. What would the shapes of the rocks collected tell about the erosion at the point?&lt;/p&gt;&#xA;" OwnerUserId="15104" LastActivityDate="2019-02-05T09:38:27.473" Title="What is the purpose of analyzing the bed-load of a river?" Tags="|rivers|geomorphology|erosion|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16172" PostTypeId="1" CreationDate="2019-02-04T20:47:45.657" Score="2" ViewCount="769" Body="&lt;p&gt;I am trying to calculate minimum and maximum daily Relative Humidity values given a min/max Specific Humidity and min/max Temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2360/how-do-i-convert-specific-humidity-to-relative-humidity&quot;&gt;some equations here&lt;/a&gt; that work with the given variables, but I have noticed that occasionally the value calculated for Minimum Relative Humidity will be greater than the value calculated for Maximum Relative Humidity. Is this accurate? It feels incorrect that a lower specific humidity and temperature would lead to a higher relative humidity, and it also doesn't seem right to say that, for example, the minimum RH was 80% while the maximum RH was 50%. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I verified &lt;a href=&quot;https://www.rotronic.com/en-us/humidity_measurement-feuchtemessung-mesure_de_l_humidite/humidity-calculator-feuchterechner-mr&quot; rel=&quot;nofollow noreferrer&quot;&gt;my results with this online calculator&lt;/a&gt;, and while it is unclear what equations are being used here, the same scenario occurs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are my C# functions for calculating RH. Specific Humidity is given as kg/kg, and Temperature in Celsius:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;    public static double CalculateRHmin(double MinSpecificHumidity, double MinTemperature)&#xA;    {&#xA;        double RHmin = 0.0;&#xA;        double es = 6.112 * Math.Exp((17.67 * MinTemperature)/(MinTemperature + 243.5)); &#xA;        double e = MinSpecificHumidity * 1013.25 / (0.378 * MinSpecificHumidity + 0.622);&#xA;        RHmin = 100 * (e / es);&#xA;        return RHmin;&#xA;    }&#xA;&#xA;    public static double CalculateRHmax(double MaxSpecificHumidity, double MaxTemperature)&#xA;    {&#xA;        double RHmax = 0.0;&#xA;        double es = 6.112 * Math.Exp((17.67 * MaxTemperature) / (MaxTemperature + 243.5));&#xA;        double e = MaxSpecificHumidity * 1013.25 / (0.378 * MaxSpecificHumidity + 0.622);&#xA;        RHmax = 100 * (e / es);&#xA;        return RHmax;&#xA;    }&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Sample execution:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tmin(Celsius) = 12.71    SHmin(kg/kg) = 0.007672     RHmin = 84.71%&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tmax(Celsius) = 23.71    SHmax(kg/kg) = 0.010929     RHmax = 60.33%&lt;/p&gt;&#xA;" OwnerUserId="15106" LastEditorUserId="15106" LastEditDate="2019-02-04T21:39:25.210" LastActivityDate="2020-12-12T17:07:50.713" Title="Can minimum relative humidity be greater than maximum relative humidity?" Tags="|temperature|humidity|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16173" PostTypeId="2" ParentId="16164" CreationDate="2019-02-04T23:55:07.903" Score="4" Body="&lt;p&gt;Reactions that can produce or destroy water:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;${\displaystyle {\hbox{H}}_{2}{\hbox{CO}}_{3}\to {\hbox{H}}_{2}{\hbox{O}}+{\hbox{C}}{\hbox{O}}_{2}}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(and there is plenty of &lt;span class=&quot;math-container&quot;&gt;${\hbox{H}}_{2}{\hbox{CO}}_{3}$&lt;/span&gt; (carbonic acid) in the sea water).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;${\displaystyle {\hbox{HCl}}+{\hbox{NaOH}}\to {\hbox{H}}_{2}{\hbox{O}}+{\hbox{NaCl}}}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Combustion: &lt;span class=&quot;math-container&quot;&gt;${\displaystyle {\hbox{C}}_{3}{\hbox{H}}_{8}+5{\hbox{O}}_{2}\to 3{\hbox{CO}}_{2}+4{\hbox{H}}_{2}{\hbox{O}}}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hydrochloric acid and sodium hydroxide: &lt;span class=&quot;math-container&quot;&gt;$HCl + NaOH \to H_2O + NaCl$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Calcium + Hydrochloric acid: &lt;span class=&quot;math-container&quot;&gt;$CaCO_3 + 2 HCl \to CaCl_2 + H_2O + CO_2$&lt;/span&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$CO_2 +H_2 \to CO + H_2O$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$2H_2 + O_2 \to 2H_2O $&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="15107" LastActivityDate="2019-02-04T23:55:07.903" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16175" PostTypeId="1" CreationDate="2019-02-05T08:22:54.327" Score="2" ViewCount="33" Body="&lt;p&gt;Would calling them hotspots be correct?&lt;/p&gt;&#xA;" OwnerUserId="8219" LastActivityDate="2019-02-05T08:22:54.327" Title="Is there a collective name given to regions in the ocean which have been studied to affect climate?" Tags="|climate|climatology|" AnswerCount="0" CommentCount="5" ClosedDate="2019-02-05T20:08:55.853" ContentLicense="CC BY-SA 4.0" />
  <row Id="16176" PostTypeId="2" ParentId="16114" CreationDate="2019-02-05T09:29:18.383" Score="5" Body="&lt;p&gt;It's just average ropy lava called pahoehoe by geologists. It's similar to dough so it easily forms ropes like the ones around the side and bulbs like the central area which is similar to a pillow except that it's called a toe. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The colder black lava flows like ropes and the hotter red lava is smooth. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/kTgqR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kTgqR.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is also from Cleopatra probably: &lt;a href=&quot;https://media.gettyimages.com/photos/ropey-lava-from-volcanic-eruption-picture-id200432059-001&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://media.gettyimages.com/photos/ropey-lava-from-volcanic-eruption-picture-id200432059-001&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another good image of a toe:&lt;BR&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/h304N.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/h304N.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;BR&gt;&#xA;&lt;A HREF=&quot;http://volcano.oregonstate.edu/book/export/html/131&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source: Oregon State University&lt;/A&gt;&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="1139" LastEditDate="2019-02-06T04:51:14.147" LastActivityDate="2019-02-06T04:51:14.147" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16177" PostTypeId="2" ParentId="16171" CreationDate="2019-02-05T09:38:27.473" Score="3" Body="&lt;p&gt;Typically rivers can be divided into three areas when it comes to erosion:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;far upstream there is the area where most erosion happens&lt;/li&gt;&#xA;&lt;li&gt;in the middle mostly transport of material happens&lt;/li&gt;&#xA;&lt;li&gt;downstream rivers mostly deposit material&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Which also can be determined by the shape and size of rocks in a streambed, which correlate directly to erosional force at that point of the river.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;larger, rough rocks are rather freshly broken off the bedrock, it takes a lot of force to move these rocks, ergo there is a lot of erosion happening, due to a combination of inclines, amount of water and shape of the riverbed&lt;/li&gt;&#xA;&lt;li&gt;smooth, smaller pebbles have been in the river for a longer time. They usually have been transported some distance from where they came into the riverbed, which wore them down to their current form. It also takes considerably less force to push/roll a smallish pebble compared to rough chunks of rock. Ergo the erosion at this point of the river is smaller&lt;/li&gt;&#xA;&lt;li&gt;sand and silt (which still are some form of rock) are typical riverbeds close to the rivers mouth. It takes ages to grind rocks to sand, and it is much easier to transport sand over long distances, so when the sand drops to the riverbed, the erosional force is close to nothing.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;For some more information, look here e.g.: &lt;a href=&quot;http://www.alevelgeography.com/the-long-profile-changing-processes-types-of-erosion-transportation-and-deposition/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.alevelgeography.com/the-long-profile-changing-processes-types-of-erosion-transportation-and-deposition/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14194" LastActivityDate="2019-02-05T09:38:27.473" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16178" PostTypeId="1" CreationDate="2019-02-05T13:30:03.890" Score="6" ViewCount="233" Body="&lt;p&gt;NASA recently landed a seismometer on Mars, with what sounds an impressive detection ability, with press reports gushing it is &quot;able to detect vibrations smaller than a hydrogen atom.&quot; A more technical description is &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;SEIS [...] is capable of measuring&#xA;  accelerations down to &lt;span class=&quot;math-container&quot;&gt;$10^{-9} m/s^2/\sqrt{Hz}$&lt;/span&gt; over frequencies of 0.001 to 10&#xA;  Hz and &lt;span class=&quot;math-container&quot;&gt;$5 \times 10^{-8} m/s^2/\sqrt{Hz}$&lt;/span&gt; from 0.01 to 100 Hz&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;-- which still seems pretty impressive. How does this compare to typical terrestrial equipment?&lt;/p&gt;&#xA;" OwnerUserId="15113" LastEditorUserId="15113" LastEditDate="2019-02-09T11:12:52.660" LastActivityDate="2019-07-12T00:42:01.377" Title="How sensitive are typical seismometers?" Tags="|seismology|instrumentation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16180" PostTypeId="1" CreationDate="2019-02-05T18:25:24.927" Score="3" ViewCount="619" Body="&lt;p&gt;I know that there are a couple of questions covering latitude and longitude for water temperature, but overall I'm more interested in the rate of temperature change by depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thought Process: Baseline geothermal gradient is defined as the rate of increasing temperature with respect to increasing depth in the Earth's interior, and approximated at about 25–30 °C/km (72-87 °F/mi) of depth near the surface in most of the world. That's maybe, what, approx. 1°F/75 ft, barring circumstance and variables unknown.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Question: Is there a similar approximate rate by which the temperatures of various depths of water can be estimated, allowing for the same acknowledgement that it's an approximation without context? Or are thermoclines so varied that such an estimated rate cannot be generalized?&lt;/p&gt;&#xA;" OwnerUserId="15117" LastActivityDate="2019-02-05T18:25:24.927" Title="Is there an approximate rate for water temperature by depth that could be modeled simply?" Tags="|temperature|hydrology|water|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16181" PostTypeId="1" AcceptedAnswerId="16182" CreationDate="2019-02-05T20:33:45.833" Score="5" ViewCount="139" Body="&lt;p&gt;According to this article from 2015 &lt;a href=&quot;https://www.seeker.com/how-much-oil-is-left-on-earth-1792718444.html&quot; rel=&quot;noreferrer&quot;&gt;How much oil is left on Earth&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1.5 trillion barrels of crude oil reserves were left in the world by end 2015&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But how much oil was already consumed worldwide since it was started to use massively in the mid 19th century? Is it most of it or a small part of it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS: I'm not sure if this question is for Earth Science SE or for Economy SE, if you think it's in the wrong SE please move it. &lt;/p&gt;&#xA;" OwnerUserId="9635" LastActivityDate="2019-02-05T23:26:54.330" Title="How much oil was consumed worldwide since it was started to use massively in the mid 19th century?" Tags="|petroleum|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16182" PostTypeId="2" ParentId="16181" CreationDate="2019-02-05T23:26:54.330" Score="6" Body="&lt;p&gt;&lt;a href=&quot;https://www.resilience.org/stories/2018-03-12/the-world-oil-supply-is-infinite-i-know-that-because-i-believe-it/&quot; rel=&quot;noreferrer&quot;&gt;Cumulative world oil production at the end of 2017 was approximately 1.36 trillion barrels&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-02-05T23:26:54.330" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16183" PostTypeId="1" AcceptedAnswerId="16184" CreationDate="2019-02-06T09:53:53.023" Score="1" ViewCount="607" Body="&lt;p&gt;We can import and read all given bands/parameters of MOD10C2, lat and lon is not given as separate band rather embedded with other bands. How we can extract from MOD10C2 hdf data in matlab.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://stackoverflow.com/questions/51557613/lat-lon-information-from-hdf-file-python&quot;&gt;Similar question found here for python&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12714" LastEditorUserId="11908" LastEditDate="2019-02-06T15:53:34.827" LastActivityDate="2019-02-06T15:53:34.827" Title="How to extract lat-lon from MOD10C2 hdf data in matlab?" Tags="|remote-sensing|snow|gis|matlab|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16184" PostTypeId="2" ParentId="16183" CreationDate="2019-02-06T15:08:27.920" Score="3" Body="&lt;p&gt;The latitude and longitude of each pixel is not stored in the HDF file. But using&lt;/p&gt;&#xA;&#xA;&lt;p&gt;metadata=hdfinfo('file_name.hdf');&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can get the info to generate those latitudes and longitudes. In metadata.Attibutes you will find this among other things:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;    GridName=&quot;MOD_CMG_Snow_5km&quot;&#xA;    XDim=7200&#xA;    YDim=3600&#xA;    UpperLeftPointMtrs=(-180000000.000000,90000000.000000)&#xA;    LowerRightMtrs=(180000000.000000,-90000000.000000)&#xA;    Projection=GCTP_GEO&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;If you rather a more human-readable format, check the &lt;a href=&quot;https://nsidc.org/data/mod10c2&quot; rel=&quot;nofollow noreferrer&quot;&gt;product specifications for MOD10C2&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There it say:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Projection&lt;/strong&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;MODIS CMG data sets are produced in a Geographic Lat/Lon&#xA;  projection. This simple projection treats geographical longitude and&#xA;  latitude degrees as if they were x- and y-coordinates in a plane.&#xA;  Figure 1 shows the geographical lat/lon projection known as Plate&#xA;  Carrée, which plots longitude and latitude degrees as coordinates on&#xA;  the x and y axes, respectively:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FnIpR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FnIpR.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Figure 1: Plate Carrée projection.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;strong&gt;Grid&lt;/strong&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The MODIS CMG consists of 7200 columns by 3600 rows. Each cell&#xA;  has a resolution of 0.05 degrees (approximately 5 km). The upper-left&#xA;  corner of the upper-left cell is -180.00 degrees longitude, 90.00&#xA;  degrees latitude. The lower-right corner of the lower right cell is&#xA;  -180.00 degrees longitude, -90.00 degrees latitude...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;With that you have more than enough information to generate the latitude and longitude vectors. Now you have to decide if you will store the center of each pixel, or one of the corners.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming you will store the center of each pixel you can generate the latitude and longitude vectors like this:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;gridSize=0.05 % arc degrees&#xA;lat=-90+(gridSize/2):0.05:90-(gridSize/2);&#xA;lon=-180+(gridSize/2):0.05:180-(gridSize/2);&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;And if you want instead matrices with the coordinates of the center of each individual pixel, you do&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;[lonGrid,latGrid]=meshgrid(lon,lat);&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-02-06T15:08:27.920" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16185" PostTypeId="2" ParentId="16167" CreationDate="2019-02-06T16:24:39.997" Score="3" Body="&lt;p&gt;Beside some unnecessary simplifications (like assuming the whole Earth is cover with water) The numbers looks right. &lt;a href=&quot;https://www.ipcc.ch/&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC&lt;/a&gt; predictions are between 0.3 and 0.8 meters by year 2100 for the most likely scenarios, and I find that perfectly consistent with your numbers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your calculation yields about 0.98 mm per year from glaciers, which using the actual surface of the sea (&lt;a href=&quot;https://en.wikipedia.org/wiki/Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;361,132,000 km&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt;&lt;/a&gt;), gives a more accurate value of 1.39 mm per year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Look at the IPCC observations and models summarized on table 13.1 of the &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter13_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chapter &quot;Sea level Rise&quot; of the Assesment Report 5&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/e0KIy.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/e0KIy.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the latest period, if you add up all land ice contributions you get that they are between 0.87 and 2.05 mm/yr, totally consistent with your estimation (of ~1 mm).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The largest single contribution is thermal expansion with 0.8 to 1.4 mm/yr.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also note that the observed contribution don't quite add up to the observed sea level rise, so we are either sub-estimating some contributions or ignoring significant ones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you multiply the current 3.2 mm/yr by 80 years you get ~26 cm by year 2100, but the point is that the rate of sea level rise is increasing (see &lt;a href=&quot;https://earthscience.stackexchange.com/a/16079/11908&quot;&gt;this answer&lt;/a&gt;). That is why all predictions are above that value.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For future predictions, thermal expansion is still the leading cause of sea level rise, as you can see on figure 3.10 of the same IPCC report:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qewA5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qewA5.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I find these predictions consistent with your numbers if you consider the current acceleration on the sea level rise rate. Unless you are talking of other predictions, not the &lt;a href=&quot;https://www.ipcc.ch/&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC&lt;/a&gt; ones. Or maybe you think that half a meter of sea level rise over 80 years is not much. If that's the case, I suggest you to research what would be the impacts in land loss, infrastructure loss and human populations displacements of such sea level rise.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-02-06T16:24:39.997" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16188" PostTypeId="1" AcceptedAnswerId="16200" CreationDate="2019-02-06T19:27:44.560" Score="11" ViewCount="3389" Body="&lt;p&gt;I was watching a science/myth Youtube channel (science mixed with a lot of speculative/fantasy content) with 2M+ followers and the Youtuber said volcano made emissions were higher than human made emissions. Now, I thought this was wrong and apparently some figures I saw in articles showed this was wrong, but then, I found this article&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.skepticalscience.com/human-co2-smaller-than-natural-emissions.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Skeptical - Human CO&lt;sub&gt;2&lt;/sub&gt; smaller than natural emissions&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Although our output of 29 gigatons of CO&lt;sub&gt;2&lt;/sub&gt; is tiny compared to the 750&#xA;  gigatons moving through the carbon cycle each year, it adds up because&#xA;  the land and ocean cannot absorb all of the extra CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So this article seems to be stating than in general natural emissions (not only volcano emissions) are indeed higher than human made emissions but human made emission are really bad anyway because they can't be absorbed and break the natural balance. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So now I really don't know if they are higher or lower. Then my question is , which percentage of CO&lt;sub&gt;2&lt;/sub&gt; emissions are human made emissions? and how volcano only natural emissions compare with human made emissions?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastEditorUserId="11908" LastEditDate="2019-03-11T21:15:45.907" LastActivityDate="2019-04-13T16:22:55.230" Title="Which percentage of $\text{CO}_2$ emissions are human made emissions?" Tags="|climate-change|climate|volcanology|co2|carbon-cycle|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16189" PostTypeId="2" ParentId="16159" CreationDate="2019-02-06T22:52:52.563" Score="2" Body="&lt;p&gt;You can get estimates from the &lt;a href=&quot;https://minerals.usgs.gov/minerals/pubs/myb.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS mineral yearbooks&lt;/a&gt;. For example, the entry on &lt;a href=&quot;https://minerals.usgs.gov/minerals/pubs/country/2015/myb3-2015-as.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Australia&lt;/a&gt; has a data table with the amounts of mined resources. Or, the entry on &lt;a href=&quot;https://minerals.usgs.gov/minerals/pubs/commodity/copper/mcs-2018-coppe.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;copper&lt;/a&gt; lists both US production and international production, including numbers of people employed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More number are available from government statistics websites, regarding employment. For example &lt;a href=&quot;https://www.aph.gov.au/About_Parliament/Parliamentary_Departments/Parliamentary_Library/pubs/rp/rp1718/Quick_Guides/EmployIndustry&quot; rel=&quot;nofollow noreferrer&quot;&gt;Australia&lt;/a&gt; and &lt;a href=&quot;https://www.bls.gov/emp/tables/employment-by-major-industry-sector.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;USA&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Digging through those websites will give you an order of magnitude of what to expect.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-02-06T22:52:52.563" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16190" PostTypeId="1" CreationDate="2019-02-07T00:54:46.780" Score="1" ViewCount="54" Body="&lt;p&gt;I am not sure if the question suits in this stack board, but I give it a try.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's assume there is a country with a population of &lt;strong&gt;327 million people&lt;/strong&gt; and a surface of &lt;strong&gt;9.6 million km²&lt;/strong&gt;, resulting in &lt;strong&gt;34 inhabitants per km²&lt;/strong&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, let's say we have a fictive war scenario, in which the country loses and has to give up land to the victors. The population sunk to &lt;strong&gt;100 million people&lt;/strong&gt; and &lt;strong&gt;10 inhabitants per km²&lt;/strong&gt; (still assuming that surface was given to victors, thus the country now has a smaller surface!!). How would I calculate the new surface with these two (now changed) variables or would I need more data?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question now is: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Is it still possible to determine the new surface of the country when both population and population density changed?&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried many ways to accomplish that, but I really have no idea how to approach it. Maybe it's possible with a system of linear equations? I have no idea.&lt;/p&gt;&#xA;" OwnerUserId="15125" LastEditorUserId="15126" LastEditDate="2019-02-07T08:08:59.013" LastActivityDate="2019-02-07T08:08:59.013" Title="How to determine (lost) surface (km²) of a country when both population and population density have changed?" Tags="|geography|mathematics|" AnswerCount="1" CommentCount="3" ClosedDate="2019-02-11T16:12:50.163" ContentLicense="CC BY-SA 4.0" />
  <row Id="16191" PostTypeId="2" ParentId="16190" CreationDate="2019-02-07T01:14:16.547" Score="3" Body="&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\text{Poulation density} = \frac{\text{Population}}{\text{Surface}}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Re-arranging &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\text{Surface} = \frac{\text{Population}}{\text{Poulation density}}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In your case&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\text{Surface} = \frac{100,000,000\, \text{inhabitants}}{10\, \text{inhabitants}\, \text{km}^{-2}}=10,000,000\, \text{km}^2$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So something doesn't make sense, because those numbers suggests that the surface of the country is now larger than before.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-02-07T01:14:16.547" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16192" PostTypeId="1" CreationDate="2019-02-07T02:11:01.210" Score="1" ViewCount="214" Body="&lt;p&gt;Either I am misunderstanding something, or reading conflicting information. Likely the former.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First off, the tropopause  is defined as the boundary between the troposphere and the stratosphere. That much seems simple enough. It is also variable in altitude; further up around the equator, than over the poles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now as I understand it, the temperature in the stratosphere is a constant -56.6C as per ISA. This seems correct. Every aircraft I've flown on has reported temperatures around that mark at altitude, give or take for ISA deviation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What confuses me is a question that asks what the height and temperature of the tropical tropopause is. The correct answer is 16Km and -75C. I'm not sure why this is supposed to be correct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I thought I'd try using ISA and the environmental lapse rate of 1.98C per 1000 ft. 16Km is ~52 000ft, so if ISA temperature on the ground is 15C, then I can easily calculate using:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;15 - 1.98 * x = y&#xA;x = (52000 / 1000) = 52&#xA;15 - 1.98 * 52 = y&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;However, the result is -88C; a significant difference from the supposedly correct -75C, and even further away from ISA's -56.6C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As per the (Environmental Lapse Rate)ELR formula, if I wanted to find at what altitude -56.6C should be:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;15 - 1.98 * x = -56.6&#xA;-1.98 * x = -56.6 - 15 = -71.6&#xA;x = -71.6 / -1.98 = 36&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;So according to this, the average height of the troposphere should be 36 000ft. This makes sense. Yet substituting -75C gives me:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;15 - 1.98 * x = -75&#xA;-1.98 * x = -75 - 15 = -90&#xA;x = -90 / -1.98 = 45&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;So even here, a -75C tropopause should occur at 45 000ft instead of 52 000ft.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What am I missing?&lt;/p&gt;&#xA;" OwnerUserId="15124" LastEditorDisplayName="user1066" LastEditDate="2019-02-07T02:20:21.897" LastActivityDate="2019-02-07T02:20:21.897" Title="Figuring out the temperature at the tropopause" Tags="|meteorology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16194" PostTypeId="2" ParentId="13327" CreationDate="2019-02-07T09:19:44.983" Score="5" Body="&lt;p&gt;The short answer to your question is yes all charge particles (positive or negative), independent (like electron, proton) or attached to other materials like cloud droplets, molecules, atoms, etc. when in motion produce magnetic field. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;If two charged particles of same charge are moving in opposite direction then they cancel out each other's magnetic field. Hence, the random motion of droplets in cloud cause net zero magnetic field away from the cloud. One can understand this by analogy to a pair of electric wires used in powering homes which does not produce appreciable magnetic field at distance when the two wires of pair are close to each other because electrons are moving in opposite directions in the two wires. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;In organized motion of charged particles that is when there is net movement of charge in a preferential direction, for example a cloud with charged droplets moving under influence of wind one can have net magnetic field. However, here too, if the cloud as whole contains both positive and negative charges in equal numbers will not produce appreciable magnetic field at a long distance because magnetic field produced by negative charges will be opposite in direction with respect to magnetic field produced by positive charge moving in same direction. If there is net positive or negative charge on cloud then the magnitude of magnetic field will depend on wind speed, which for atmospheric range of wind speeds will produce very small magnetic field. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The appreciable magnitude of magnetic field is produced during lighting since large amount of charge moves along a particular path with high velocity but such movements are momentary and as soon as the lighting strike is over, the magnetic field produced starts dying. If a compass needle is having significant inertia then before the needle can move under influence of newly produced magnetic field, the magnetic field will vanish and hence ordinary compasses are unlikely to show effect of lightning strikes. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Further Reading:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Fundamentals of Lightning by Vladimir A. Rakov, Cambridge Univesity Press, ISBN 978-1-107-07223-7, 2016&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="10780" LastEditorUserId="10780" LastEditDate="2019-02-11T12:49:35.907" LastActivityDate="2019-02-11T12:49:35.907" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16195" PostTypeId="1" AcceptedAnswerId="16199" CreationDate="2019-02-07T16:28:45.270" Score="-1" ViewCount="258" Body="&lt;p&gt;Military powers like USA, Rusia and China have programs to heat through electromagnetic waves the Ionosphere. HAARP supposedly is a research program, but run by part of the military of US (Air Force and Navy) . Rusia has SURA and China IIRC has CSES. Supposedly one of the tests made by these programs affected the city of Vasilsursk where they had electrical alterations. A physicist from China called Gong Shuhong said he followed the tests done by Russia and China in cooperation and that he believes it wont have important consequences in a global scale but that it could have consequences in a regional scale. My question is, is it known if HAARP-like programs have effects on climate? The programs manager said they dont but several articles online mention researchs which says they could.&lt;/p&gt;&#xA;" OwnerUserId="9635" LastActivityDate="2019-02-08T02:36:46.823" Title="Do HAARP-like programs have effects on climate?" Tags="|atmosphere|climate-change|ionosphere|" AnswerCount="1" CommentCount="5" ClosedDate="2019-02-08T09:06:12.193" ContentLicense="CC BY-SA 4.0" />
  <row Id="16199" PostTypeId="2" ParentId="16195" CreationDate="2019-02-08T01:38:37.937" Score="5" Body="&lt;p&gt;Not in any significant way.&#xA;As an analogy, if you are looking for a suspect responsible for knocking down the trees in a forest, you shouldn't worry about someone carrying a Swiss army knife, it just isn't the right tool.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/High_Frequency_Active_Auroral_Research_Program&quot; rel=&quot;nofollow noreferrer&quot;&gt;HAARP has a power of 3.6 MW&lt;/a&gt;, which is a lot, but nothing compared with the energy in a modest storm. As an example, a single lightning bolt can deliver 1.4 MWh (&lt;a href=&quot;https://en.wikipedia.org/wiki/Harvesting_lightning_energy&quot; rel=&quot;nofollow noreferrer&quot;&gt;5 billion joules&lt;/a&gt;) in a fraction of a second, and HAARP would need half an hour to deliver the same amount of energy (assuming perfect efficiency). And a single thunderstorm can deliver hundreds of lightning bots.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;HAARP is designed to excite the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ionosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;ionosphere&lt;/a&gt;, a very low density part of the atmosphere where charged particles interact heavily with electromagnetic radiation. But the ionosphere is WAY up, about 60 km high or more (that's 6 times the altitude of commercial flights), and what happens there have little to do with the weather we experience down at the surface. That's why you will never hear about the ionosphere in a TV whether forecast.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, &lt;a href=&quot;https://en.wikipedia.org/wiki/Jet_stream&quot; rel=&quot;nofollow noreferrer&quot;&gt;jet streams&lt;/a&gt; that are notable for existing at very high altitude and make an important impact on weather, are 16 km high AT MOST, just around the corner compared with the ionosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To give you a bit more of context, the &lt;a href=&quot;https://www.space.com/17961-supersonic-skydive-worlds-highest-space-jump.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;record braking sky dive by Felix Baumgartner&lt;/a&gt;, was made from 39 km high, and if you see &lt;a href=&quot;https://www.youtube.com/watch?v=vvbN-cWe0A0&quot; rel=&quot;nofollow noreferrer&quot;&gt;the footage of the jump&lt;/a&gt; you will realize that he was almost in outer space. Well, the ionosphere starts 21 km higher than that!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So even if HAARP does create a sizable perturbation of the ionosphere, that wouldn't impact the weather, let alone the climate. It will impact radio communications, but not much more than that.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-08T02:36:46.823" LastActivityDate="2019-02-08T02:36:46.823" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16200" PostTypeId="2" ParentId="16188" CreationDate="2019-02-08T05:02:49.423" Score="11" Body="&lt;p&gt;First of all, the amount of carbon cycling trough the Earth's system is irrelevant to the discussion of the changes in atmospheric &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; concentration or ocean acidification. In the same way that the volume of water cycled by the filtering system of a swimming pool is irrelevant to the level of the pool. What matters are the net inputs and outputs of water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's look at this diagram of the Earth's carbon storage and fluxes through the carbon cycle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rqQsg.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rqQsg.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Figure by &lt;a href=&quot;https://serc.carleton.edu/integrate/teaching_materials/earth_modeling/bice_story.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dave Bice&lt;/a&gt; at &lt;a href=&quot;https://serc.carleton.edu/integrate/teaching_materials/earth_modeling/student_materials/unit9_article1.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Carleton College&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The total amount of carbon is indeed huge, and the total fluxes add up to almost 700 Gigatons of carbon per year. Note that only ~400 Gt are transferred as &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt;, the rest is organic matter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The number in the diagram are not precise, but they are very good approximations. The figure given in the diagram for humans burning fossil fules is 6 Gt of carbon, that corresponds to 22 Gt of &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt;, which added to other human made emissions probably add up to something similar to the 29 Gt of the reference you cited.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The amount of &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; released by volcanic activity varies widely in time, but the amount given in the figure is an average value, and amounts to 0.6 Gt of Carbon, equivalent to 2.2 Gt of &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt;. &lt;strong&gt;But pretty much the same amount is removed by subduction. Therefore, volcanic activity is not a significant LONG TERM source of &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt;.&lt;/strong&gt; And by long term I mean millions of years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So you can argue that natural emissions are larger than human emissions. Sure. The respiration of plants and animals produce 8 times more &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; than humans, but plants take it back through photosynthesis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Atmospheric &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; have varied widely through Earth's history, but in the last several thousands years it have been pretty stable, because all the sources were in balance with the sinks, leading to a very small net change in &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; concentration in the atmosphere and oceans (there in the form of carbonic acid).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this balance was disrupted by the industrial revolution and human emissions, mostly due to the use of fossil fuels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Going back to the swimming pool analogy: evaporation might be tiny compared with the volume of water turned around by the filtering system, but give it long enough time and your swimming pool will be dry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We added a source of carbon in the carbon cycle, and if we don't remove it or add an equivalent sink (&lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_sequestration&quot; rel=&quot;nofollow noreferrer&quot;&gt;carbon sequestration&lt;/a&gt;), the concentration of &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; in the atmosphere and carbonic acid in the oceans will keep rising.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Returning to your question, using the figures in the diagram, human emissions would account for ~3% of total emissions. But that doesn't matter at all. The point is that human emissions are the ones upsetting a system that was in balance, and are triggering an increase in atmospheric &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; concentrations and consequent ocean acidification.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-04-13T16:22:55.230" LastActivityDate="2019-04-13T16:22:55.230" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="16201" PostTypeId="1" AcceptedAnswerId="16210" CreationDate="2019-02-08T11:27:05.670" Score="4" ViewCount="755" Body="&lt;p&gt;Are the levels of natural (before the industrial revolution) levels of CO2 and ppm known? Also as a related question, should the &quot;natural&quot; levels be considered before the industrial revolution or before the start of the deforestation 8000 years ago?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastEditorUserId="11908" LastEditDate="2019-03-11T21:15:58.930" LastActivityDate="2019-03-11T21:15:58.930" Title="What are the ranges of natural (or pre-industrial era) levels of CO2 in the atmosphere in ppm and tons?" Tags="|climate-change|climate|paleoclimatology|co2|deforestation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16205" PostTypeId="2" ParentId="16178" CreationDate="2019-02-08T17:27:38.463" Score="3" Body="&lt;p&gt;The table below gives you a nice summary snapshot up to 2015.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6PAwb.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6PAwb.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Reference:  Kamp, P.J., 2016. Towards an Ultra Sensitive Seismic Accelerometer (Master's thesis, University of Twente).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sercel accelerometer, the top one in the table, is widely used in Oil and Gas industry, for example, to monitor induced seismicity. Below is an excerpt from the article: &quot;A high-sensitivity MEMS-based accelerometer&quot;, by J. Laine and D. Mougenot (2014), The Leading Edge, 33(11).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1 g is about ~10 m/s^2 (9.80665) so 1 ng ~ 10^-8  m/s^2. For the Sercel then 360 ng mentioned in the paper (three times the rms noise level) = 3.6 ^10-6 m/s^2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Correct me if I am wrong.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5V9YK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5V9YK.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="144" LastEditorUserId="6031" LastEditDate="2019-07-12T00:42:01.377" LastActivityDate="2019-07-12T00:42:01.377" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16210" PostTypeId="2" ParentId="16201" CreationDate="2019-02-09T01:29:07.963" Score="7" Body="&lt;p&gt;There is no such thing as a single &quot;natural&quot; level of &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt;: In Earth's history, there have been levels much higher and much lower than currently, and they are all natural.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What we should consider instead is what levels of &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; are compatible with the mild and stable climate that humanity has enjoyed for the last few millennia, or conversely, which levels will upset the climatic equilibrium and send Earth into a completely new climatic regime.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The means to measure atmospheric &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; concentrations were invented during the industrial revolution, so we don't have direct records before that. However, we can reconstruct past &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; concentrations using proxies such as the analysis of air bubbles trapped deep within the ice in Antarctica.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ice cores were drilled up to ~600 meters deep between 1987 to 1993 at &lt;a href=&quot;https://en.wikipedia.org/wiki/Law_Dome&quot; rel=&quot;nofollow noreferrer&quot;&gt;Law Dome&lt;/a&gt; (Antarctica), allowing the reconstruction of &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; concentrations from the last millennium, and it looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jUawO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jUawO.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where the darker blue at the end corresponds to the direct instrumental record (&lt;a href=&quot;https://www.co2.earth/co2-ice-core-data&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Later, another ice core from Vostok station in Antarctica was drilled to a depth of more than 3.6 km, allowing the reconstruction of atmospheric &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; concentration during the last 400,000 years, and it looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7ayCs.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7ayCs.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Figure &lt;a href=&quot;https://www.co2.earth/co2-ice-core-data&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data from Law Dome and that of modern records at Mauna Loa, Hawaii are also displayed on the end for comparison.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More ice cores have been drilled after Vostok, and all of them tell more or less the same story.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So we know that atmospheric &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; concentrations now are much higher than at any other time since we invented agriculture. And the people that think they know how the atmosphere works run models and say that current levels will significantly upset the climate as we know it. On the other hand, the people who don't know how the atmosphere works (like me), should just stop producing so much &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt;, because we don't ourselves know what the effects could be, and at the same time, we rely on the climate to stay nice and stable to keep your flourishing society alive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To address the last bit of the question, to transform 1 PPM by volume of atmospheric &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; into a GigaTon of Carbon you &lt;a href=&quot;https://cdiac.ess-dive.lbl.gov/pns/convert.html#3.&quot; rel=&quot;nofollow noreferrer&quot;&gt;just have to multiply by  2.13&lt;/a&gt;. So the pre-industrial base level during the last millennia of 280 PPM is equivalent to ~596 GtC or 2,187 Gt of &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; (multiply again by 44/12, the ratio of &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; mass to C mass).&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="6298" LastEditDate="2019-02-12T00:50:13.613" LastActivityDate="2019-02-12T00:50:13.613" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="16211" PostTypeId="5" CreationDate="2019-02-09T02:19:18.337" Score="0" Body="&lt;p&gt;Use this tag whem you're asking about things like&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Seismometers&lt;/li&gt;&#xA;&lt;li&gt;weather balloons&lt;/li&gt;&#xA;&lt;li&gt;gauges&lt;/li&gt;&#xA;&lt;li&gt;soil augers&lt;/li&gt;&#xA;&lt;li&gt;polarimeters&lt;/li&gt;&#xA;&lt;li&gt;magnetometers&lt;/li&gt;&#xA;&lt;li&gt;mass spectrometers&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Please use the &lt;a href=&quot;/questions/tagged/remote-sensing&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged &amp;#39;remote-sensing&amp;#39;&quot; rel=&quot;tag&quot;&gt;remote-sensing&lt;/a&gt; tag instead of this one when asking about radar, satellite  imagery, aerial photography or other remote sensing technologies. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some of these instruments can be used for other sciences, so please remember to limit your questions to their  use within an Earth Science field as described in the &lt;a href=&quot;http://earthscience.stackexchange.com/help&quot;&gt;help center&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2019-02-09T13:24:37.737" LastActivityDate="2019-02-09T13:24:37.737" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16212" PostTypeId="4" CreationDate="2019-02-09T02:19:18.337" Score="0" Body="Applied to questions about the use of instruments in earth sciences.&#xD;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2019-02-10T02:04:04.503" LastActivityDate="2019-02-10T02:04:04.503" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16213" PostTypeId="1" CreationDate="2019-02-09T04:35:03.477" Score="9" ViewCount="189" Body="&lt;p&gt;Are there any estimates for the reduction of global solar insolation at the Earth's surface that a Tambora scale eruption would bring? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If our electrical power generation became heavily reliant on solar pv would it bring about a substantial reduction in output capacity?&lt;/p&gt;&#xA;" OwnerUserId="12688" LastEditorUserId="11908" LastEditDate="2019-03-11T21:12:00.623" LastActivityDate="2019-03-11T21:12:00.623" Title="The Tambora eruption caused the &quot;Year without a summer&quot;. How much would such an eruption today affect the output of solar pv on a global scale?" Tags="|atmosphere|climate|volcanology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16216" PostTypeId="2" ParentId="16213" CreationDate="2019-02-09T17:27:01.790" Score="4" Body="&lt;p&gt;Volcanic eruptions effectively inject large quantities of aerosols in the upper layers of the atmosphere, increasing Earth's albedo and reducing the intensity of the solar radiation reaching the surface. Such reduction would indeed lower the solar energy available to solar panels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These effects of volcanic eruptions have been studied by &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2008JD010239&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gao et al. (2008)&lt;/a&gt; and &lt;a href=&quot;https://www.earth-syst-sci-data.net/5/187/2013/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Crowley and Unterman (2013)&lt;/a&gt;. Both studies were combined by the &lt;a href=&quot;http://www.climatechange2013.org/report/full-report/&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC Working Group I during the assessment report 5 (2013)&lt;/a&gt;, and summarized on the figure 8.18 (&lt;a href=&quot;http://www.climatechange2013.org/images/report/WG1AR5_Chapter08_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chapter 8&lt;/a&gt;), together with other climatic forcings:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/14geX.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/14geX.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see that the largest drop in effective radiative forcing happens in 1815 as a consequence of the &lt;a href=&quot;https://en.wikipedia.org/wiki/1815_eruption_of_Mount_Tambora&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tambora eruption&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, that event goes out the scale of the plot. However, the data is available on Table AII.1.2 of &lt;a href=&quot;http://www.climatechange2013.org/images/report/WG1AR5_AnnexII_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Annex II&lt;/a&gt;, were we can see that the minimum value indeed happens in 1815 and reaches –11.629 W/m².&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Considering the typical amount of energy received from the Sun under clear skies at seal level is roughly &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_irradiance#Irradiance_on_Earth&amp;#39;s_surface&quot; rel=&quot;nofollow noreferrer&quot;&gt;1,000 W/m²&lt;/a&gt;, the irradiation drop produced by Tambora would represent a drop of about 1% on the energy reaching the Earth's surface. Of course, much larger local effects could be observed due to transient and more localized dense ash clouds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Therefore, at a global scale, if a new &lt;a href=&quot;https://en.wikipedia.org/wiki/Year_Without_a_Summer&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;year without summer&quot;&lt;/a&gt; where to happen, photovoltaic energy output would drop by ~1%.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, larger effects would take place if the eruption happens to be close to the most important areas for photovoltaic energy production.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-11T14:45:04.200" LastActivityDate="2019-02-11T14:45:04.200" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16219" PostTypeId="2" ParentId="9450" CreationDate="2019-02-10T03:14:04.160" Score="3" Body="&lt;p&gt;No. If that were the case, the Sun would eventually develop a net charge. Let's imagine that's the case and the Sun develops a net  positive charge. That charge would eventually stop negative particles from flying away and facilitate the ejection of positive ones. This regime would then restore the neutral charge of the Sun.&#xA;This negative feedback makes sure the Sun remains neutral and that Solar winds carry no net charge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See this Q&amp;amp;A for more details:&lt;a href=&quot;https://physics.stackexchange.com/questions/257418/does-the-solar-wind-correspond-to-a-net-electrical-current&quot;&gt;Does the solar wind correspond to a net electrical current?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-02-10T03:14:04.160" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16227" PostTypeId="2" ParentId="10236" CreationDate="2019-02-11T09:50:58.197" Score="1" Body="&lt;p&gt;It sounds like Ingersoll was referring to &lt;a href=&quot;https://en.wikipedia.org/wiki/Antidynamo_theorem&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cowling's Theorem&lt;/a&gt; -- that flow in a planet's core that is purely symmetric around the planet's rotation axis (that would give a magnetic dipole field with no tilt) cannot produce a self-sustaining dynamo.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So a magnetic field that is purely symmetric around the rotation axis, as looks to be the case for Saturn, should not be possible by known dynamo theory. As best we know, all other self-sustaining planetary dynamos (and those of stars) have some degree of asymmetry that leads to a self-sustaining dynamo.&lt;/p&gt;&#xA;" OwnerUserId="14123" LastActivityDate="2019-02-11T09:50:58.197" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16228" PostTypeId="1" CreationDate="2019-02-11T15:13:24.930" Score="3" ViewCount="86" Body="&lt;p&gt;I have performed an experiment using a shaking table to simulate the response of a soil base structure to an earthquake. A multi-floor structure was placed on a sand (90% relative density) bed and the bed was shaken horizontally at frequencies of 1-4 Hz for amplitudes of 1 mm, 2 mm and 3 mm. The acceleration of the base of the structure and of its floors was recorded, &lt;em&gt;Frequency - Relative acceleration&lt;/em&gt; (= floor acceleration/base acceleration) graphs were drawn and the damping ratio and resonant frequency were extracted for each case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I found is that, as the amplitude of the shaking is increased, the damping ratio decreases, as well as the resonant frequency. Theoretically, for a linear system, the amplitude should not influence these two parameters, which led me to the conclusion that sand behaves in a non-linear way. However, I do not understand exactly what aspects of the sand's behaviour and of the sand-structure interaction lead to a lower damping ratio and resonant frequency. Any help on clarifying this would be appreciated!&lt;/p&gt;&#xA;" OwnerUserId="15152" LastActivityDate="2019-12-02T02:59:58.277" Title="How can shake amplitude influence the damping ratio and resonant frequency of a soil base structure?" Tags="|earthquakes|soil-science|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16231" PostTypeId="1" CreationDate="2019-02-11T20:06:47.670" Score="1" ViewCount="58" Body="&lt;p&gt;How much would 1 m3 of an ideal mineral SOIL that has been completely dried (all pore space is empty) weigh in Mg on Earth?  Answer = ______ Mg&lt;/p&gt;&#xA;" OwnerUserId="15103" LastActivityDate="2019-02-11T20:06:47.670" Title="soil that is dried (no pore space) weight?" Tags="|soil|soil-moisture|soil-science|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="16236" PostTypeId="1" AcceptedAnswerId="16239" CreationDate="2019-02-12T10:08:57.080" Score="4" ViewCount="145" Body="&lt;p&gt;Below is an excerpt from &lt;em&gt;The Biology of the Indian Ocean&lt;/em&gt;,  Bernt Zeitzschel, Sebastian A. Gerlach&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The more vigorous atmospheric and oceanic circulation during the SW&#xA;  monsoon causes not only the development of a strong western boundary&#xA;  current, the Somali Current, but also intense upwelling in several&#xA;  places. The circulation appears to penetrate deeper, affecting the&#xA;  movements of water masses below the thermocline. The formation of the&#xA;  Somali Current as a strong western boundary current of the monsoon&#xA;  gyre causes a strong baroclinic adjustment of the structure along the&#xA;  coast of Somalia. This baroclinic structure is noticeable as deep as&#xA;  1000 m, but is especially pronounced in the upper 400 m. &lt;strong&gt;The strong&#xA;  winds parallel to the coast intensify the baroclinicity&lt;/strong&gt; in the upper&#xA;  layer and cause, in addition, strong upwelling along the coast.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Through what mechanism do strong winds cause intensification of baroclinicity in the ocean?&lt;/p&gt;&#xA;" OwnerUserId="8219" LastActivityDate="2019-02-12T15:13:58.097" Title="How to strong winds cause baroclinic intensification in the upper ocean?" Tags="|atmosphere|oceanography|wind|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16237" PostTypeId="2" ParentId="8267" CreationDate="2019-02-12T11:55:43.500" Score="0" Body="&lt;p&gt;This looks like petrified fruit. If you look between the two lobes you will see a lighter round patch that was the attachment area to the parent plant from which this fruit/seed had fallen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's probably fruit, as a seed would have had different shape, and it would seem to have fallen at a time of extremely hot weather  becoming quickly dehydrated after being invaded by some form of herbivore. I would discount bivalve activity but a terra based gastropod may have been the perpetrator before the fruit became petrified. &lt;/p&gt;&#xA;" OwnerUserId="15163" LastEditorUserId="595" LastEditDate="2019-02-12T12:13:45.193" LastActivityDate="2019-02-12T12:13:45.193" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16238" PostTypeId="1" CreationDate="2019-02-12T14:36:50.243" Score="1" ViewCount="93" Body="&lt;p&gt;I am very new in this area and wondering if anyone can answer my following questions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am running WRF (4.0.3, ideal) to study rounding and truncation. I use the NCL (6.5.0) print command to access variable values in the WRF output file.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;I have noticed that some variables have greater precision than others. Is there a way to change the level of precision for individual variables?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;I have been using em_b_wave and ideal.exe to initialize the WRF model. The values and variables in the output file are the same no matter how many MPI tasks I use. Why?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Is WRF output exactly the same when using a single MPI task vs. using more than one MPI task? I assume there might be slight differences in rounding and truncation when using different number of processors.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;And at the end, I am not sure if the way that I am reading the values and variables from the output files which are binary are correct or not. I am using some NCL scripts now, but have no idea if that is the right way to read the binary output files ...&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I would appreciate any help.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you,&#xA;Sara &lt;/p&gt;&#xA;" OwnerUserId="15166" LastActivityDate="2019-02-12T14:36:50.243" Title="How to control output precision when running WRF?" Tags="|atmosphere-modelling|numerical-modelling|wrf|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16239" PostTypeId="2" ParentId="16236" CreationDate="2019-02-12T15:13:58.097" Score="2" Body="&lt;p&gt;Strong upwelling-favorable winds (like the ones described) cause coastal upwelling in the following manner: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Winds in these systems flow parallel to the coast (with the coast to the left in the northern hemisphere or to the right in the southern hemisphere) and generate upwelling dynamics. &lt;/li&gt;&#xA;&lt;li&gt;Surface &lt;a href=&quot;https://en.wikipedia.org/wiki/Ekman_transport&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ekman balance&lt;/a&gt; is setup (in deep enough waters) with water transport being to the right (left) of the wind in the northern (southern) hemisphere. The result is a deficit along the coast that requires a compensating flow in the deeper part of the water column bringing usually colder waters to the surface.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eihoE.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eihoE.gif&quot; alt=&quot;upwelling animation&quot;&gt;&lt;/a&gt; Source &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Upwelling_animated.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;Commons Wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The resulting density (mostly controlled by temperature in these systems, but sometimes affected by salinity in areas with river influences) shows a strong horizontal gradient. A strong horizontal gradient in density is the definition of strong baroclinicity. That strong gradient can even be visible in a temperature front when the thermocline reaches the surface (SST image below). &lt;/li&gt;&#xA;&lt;li&gt;Additionally, the density gradient can establish a &lt;a href=&quot;https://en.wikipedia.org/wiki/Thermal_wind&quot; rel=&quot;nofollow noreferrer&quot;&gt;thermal wind&lt;/a&gt; balance that results in a coastal upwelling current jet flowing in the same direction of the wind. The horizontal gradient in density is proportional to the vertical gradient in velocity&#xA;&lt;span class=&quot;math-container&quot;&gt;$\mathrm{{\delta\rho\over\delta x} \propto {\delta v\over\delta z}}$&lt;/span&gt; . As velocity is zero at the bottom, this results in a strong velocity near the surface. This is what we understand as &quot;intensifying the baroclinicity in the upper layer&quot;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Ave5l.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ave5l.gif&quot; alt=&quot;SST upwelling&quot;&gt;&lt;/a&gt; Source: &lt;a href=&quot;https://airsea-www.jpl.nasa.gov/cos/theory/upwelling_dynamics.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Satellite image of SST showing multiple upwelling centers and cold filaments off central California&lt;/a&gt; (Courtesy of E. Armstrong).&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2019-02-12T15:13:58.097" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16240" PostTypeId="1" CreationDate="2019-02-12T18:17:54.677" Score="2" ViewCount="167" Body="&lt;p&gt;Where can I find the locations on snow fall recording stations in a particular United States county or zip code? Is there a way that I can find an hour by hour recent history of snow fall? Hour by hour for the last 7 days would be interesting but even the last 24 hours would be very helpful. I need to to know where and when to dispatch crews to remove snow from office and apartment buildings, often in the middle of the night when I don't have eyes on the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I may have to resort to installing web cams so I can personally review the conditions remotely.  The lake level stations are so accurate and easily accessible, I thought they might have sometime for precipitation as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would prefer reports in inches of precipitation rather than inches of snow, but either would work. I find the former to be more accurate for my needs. It's the amount of water that needs to me moved that matters, no matter if it is densely packed or loosely packed. &lt;/p&gt;&#xA;" OwnerUserId="15167" LastEditorUserId="15167" LastEditDate="2019-03-01T03:30:23.163" LastActivityDate="2019-03-01T03:30:23.163" Title="Where can I find a list of snow fall recording stations in my zip code?" Tags="|meteorology|open-data|snow|database|cryosphere|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16241" PostTypeId="2" ParentId="16240" CreationDate="2019-02-12T18:39:49.503" Score="1" Body="&lt;p&gt;Were to find hourly data will depend on your location, as you will probably need to access the national weather network of the country of your interest. Global climatic databases usually record data on daily basis. Like the &lt;a href=&quot;http://Global%20Historical%20Climate%20Network&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Historical Climate Network&lt;/a&gt;, you can search for all the station in that network and query snowfall data in the &lt;a href=&quot;https://climexp.knmi.nl/selectdailyseries.cgi?id=someone@somewhere&quot; rel=&quot;nofollow noreferrer&quot;&gt;KNMI Climate Explorer&lt;/a&gt;. This is a example query of all the stations between 50 and 51° North and 120 and 122° West (to convert ZIP codes to coordinates you can use &lt;a href=&quot;https://geocoder.ca/&quot; rel=&quot;nofollow noreferrer&quot;&gt;geocoder&lt;/a&gt; or other similar services):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/82jgg.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/82jgg.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It returns 39 stations, each one with a record like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rugY1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rugY1.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And you can also download the raw data.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-12T18:55:54.147" LastActivityDate="2019-02-12T18:55:54.147" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16244" PostTypeId="1" CreationDate="2019-02-13T15:08:03.550" Score="3" ViewCount="997" Body="&lt;p&gt;I am analyzing the effect of extreme weather on milk production (Panel data). I am looking at direct effects and indirect effects of weather on animal (milk production). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding extreme weather, I am looking at the following variables - Tmin, Tmax and Precipitation. The dependent variable (milk litres) is a monthly cumulative value. Therefore, I have to generate more meaningful extreme weather variables at the monthly level. For e.g. No of days of Tmax &gt; 95th percentile, No of days of Temperature Humidity Index (THI) at certain threshold, etc. To determine the no of days of Tmax &gt;95th percentile, I have used the following method. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have calculated the Tmax value of 95th percentile for each month and for each farm  using the base period data 1980-2010. Then I have applied the determined value on daywise data (2011-2015) to determine whether the day value is exceeding the 95th percentile value. If it exceeds, then given 1 else 0. Then aggregated the no of days (with Tmax &gt;95th percentile) by month. Do you think that this method will identify the extremes? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recently, I have come across a method to calculate daywise percentiles, high daily temperature for a specific day in a year with the high temperature for that same day across all years. Days with above 95th percentile are selected as events.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have tried to compare both the methods for a farm location. I found that previous method (monthwise percentiles) identify less number of events in comparison to the recent method. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Suggestions are welcome to use the correct method.&lt;/p&gt;&#xA;" OwnerUserId="15174" LastActivityDate="2019-02-14T17:10:23.277" Title="Method to determine Tmax 95th percentile in a climate data" Tags="|climate|extreme-weather|" AnswerCount="1" CommentCount="3" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16248" PostTypeId="1" AcceptedAnswerId="16249" CreationDate="2019-02-14T15:31:52.537" Score="2" ViewCount="44" Body="&lt;p&gt;When working with extreme hydro-meteorological events, flood in particular, it is common procedure to classify each event by its return &lt;a href=&quot;https://en.wikipedia.org/wiki/Return_period&quot; rel=&quot;nofollow noreferrer&quot;&gt;period/recurrence interval&lt;/a&gt;. This probabilistic measure has the quality to provide a standard and homogeneous measure of the different events that eventually happened in diverse geographical areas, given their relative frequency. So, a 100-year flood is a potentially devastating event both for a flood prone area, and for an area where flood events are extremely rare.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My problem is now how to set a reasonable threshold to group events characterized by a &quot;similar&quot; return period. For instance, let's assume I want to set three classes: mild, middle, and severe flood events, what would be a reasonable return period cut? Is there any similar procedure for structural engineering/water infrastructure design? It would be lovely if you could also provide some references justifying your choice.&lt;/p&gt;&#xA;" OwnerUserId="8087" LastEditorUserId="8087" LastEditDate="2019-02-15T11:24:07.683" LastActivityDate="2019-02-15T11:24:07.683" Title="What would be a reasonable set of thresholds for flood severity classes?" Tags="|hydrology|extreme-weather|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16249" PostTypeId="2" ParentId="16248" CreationDate="2019-02-14T15:59:40.517" Score="3" Body="&lt;p&gt;One existing classification for return period events is minor and major flows, which basically classifies floods into those that the storm network (pipes and small conveyance network) is designed to handle, typically in the 2-10 year event range, and those more major floods which will overwhelm the stormwater infrastructure and are mainly conveyed by overland topography and larger flow channels/watercourses (&gt;10 year event). The definition of major and minor return periods depends on the level of design in your are of study, but that is one classification. This distinction in major/minor flows is common and you can find lots of resources, one example is in the &lt;a href=&quot;http://www.mto.gov.on.ca/english/publications/drainage/stormwater/section10.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ontario Drainage Manual&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given that you want a small/medium/large classification, I would put minor flows (say 5 year and smaller, based on the study area) into the small category, everything above a minor flow to the 100 year event into the medium category, and everything 100 year or larger (i.e. 100 year and regulatory event) into the large flood category. The 100 year as you mentioned is a very common standard for a large flood event. The Regulatory event is typically the largest observed flood on record or similar estimate for a larger than 100 year flood event.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope that helps!&lt;/p&gt;&#xA;" OwnerUserId="8440" LastActivityDate="2019-02-14T15:59:40.517" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16251" PostTypeId="2" ParentId="16244" CreationDate="2019-02-14T17:10:23.277" Score="2" Body="&lt;p&gt;You're heading along the right lines, but there are a few things you might want to make sure you've thought about when deciding on your method.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;1. Notation&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A long time ago there was an Expert Team on Climate Change Detection, Monitoring and Indices (ETCCDMI) that came up with some naming conventions for various climate indices, because it gets a bit cumbersome to talk about things like &quot;the annual minimum of daily maxima&quot; all the time.  They were first described in this paper:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alexander et al. (2006), Global observed changes in daily climate extremes of temperature and precipitation, J. Geophys. Res., 111, D05109, doi:10.1029/2005JD006290&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In your case, the 95th percentile of daily maximum temperature (TX) would be called TX95p.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;2. Think about your science question&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most temperature time series for the last few decades will contain a warming trend, which has the effect that hot days will occur more frequently in the later part of the data than the earlier part.  You need to think about what aspect of temperature causes the impact in the system you're studying to decide if you need to detrend the data or not.  If the problem occurs when the absolute temperature exceeds some limit, then you probably don't want to detrend.  If the the system can adapt to the mean change but the problem occurs if the hot days occur in clusters, then you may want to detrend the data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You need to make similar decisions about de-seasonalising the data, which you're currently doing by considering each calendar month separately when estimating TX95p.  In most cases it does make sense to de-seasonalise the data, particularly in places with a large annual cycle.  While you're at it, think about whether you need to analyse the whole year.  If the impact you're worried about only occurs in a particular season, then target your analysis to that season: e.g., a warm extreme in summer typically has a greater impact than a warm extreme in winter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;3. Estimating TX95p&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unless you have some specific hypothesis or protocol that needs to separate the periods, I'd use all years of data (1980-2015) to estimate TX95p.  If you're assuming that TX95p is stationary between the periods, then using more years will give you a more accurate estimate of the threshold.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Recently, I have come across a method to calculate daywise percentiles, high daily temperature for a specific day in a year with the high temperature for that same day across all years. Days with above 95th percentile are selected as events.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What you've found here it that there's no standard way of estimating TX95p, the climatological threshold for a hot day.  A quick glance through my notes throws up various methods:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Daily climatology using 15-day window centred on day-of-year (Della-Marta et al, 2007; Fischer and Schaer, 2010; Perkins et al, 2012; Teng et al, 2013)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Daily climatology using 10-day window centred on day-of-year after detrending the data (Kreuger et al, 2015)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Daily climatology using 5-day window centred on day-of-year (Lorenz et al, 2010; Mueller and Seneviratne, 2012)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Daily climatology using 1-day window and then smoothed with a Fast Fourier Transform (Eade et al, 2012).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Single threshold value using all daily TX in summers (Vautard et al, 2013).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I have tried to compare both the methods for a farm location. I found that previous method (monthwise percentiles) identify less number of events in comparison to the recent method.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I suspect that trying to estimate daily TX95p from just 31 values for each day of year gives very inaccurate results, whereas estimating monthly TX95p from about 930 (31*30) values is more realistic.  The daily estimates probably jump around from one day of year to the next, which would clearly be a sampling artefact, and yield values that are quite close to TX100p, so you diagnose fewer hot days.  This is why the papers listed above use various smoothing methods.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2019-02-14T17:10:23.277" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16252" PostTypeId="2" ParentId="6723" CreationDate="2019-02-14T19:03:53.113" Score="-2" Body="&lt;p&gt;Perhaps a Comet miles across broke up as it entered the Earth's atmosphere traveling from South to North about 12900 years ago and various large portions would explain all the anomalies including the &quot;new crater&quot; in Greenland, North Carolina Bays and Nebraska impacts and destruction with fire of Megalithic sites in Peru...slamming into the huge Laurentide Ice Sheets absorbed most but not all of the impact from the many large pieces of such a monstrous set of impacts something like that from a shotgun that would have been 100x to 1000x (or more) more powerful than Tunguska or the 1815 Tambora Volcanic event (where there was &quot;no summer&quot;) except that the effect lasted 1200-1300 years (10900 BC to 9600 BC). An increase of Platinum 100 fold circa 12890 BP +- 5 years in Greenland Ice Cores hint that such a hypothesis generally known as the Younger Dryas Impact Hypothesis may well have happened but there are many criticisms such as the fact that the amount and volume of fires was not especially high during that 1200-1300 year time period and that the 10890 BC or 12800-12900 BP time period is not agreed upon for some of the phenomena. So it remains a HYPOTHESIS and not enough evidence yet to make it a proper CONJECTURE. &lt;/p&gt;&#xA;" OwnerUserId="15180" LastActivityDate="2019-02-14T19:03:53.113" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16255" PostTypeId="1" CreationDate="2019-02-15T11:08:57.560" Score="2" ViewCount="97" Body="&lt;p&gt;This bugged me for a while:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pyroclastic flows are fast (up to 700 km/h (430 mph) according to Wikipedia) and typically roll down the slopes of a volcano. E.g. here &lt;a href=&quot;https://www.youtube.com/watch?v=Cvjwt9nnwXY&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=Cvjwt9nnwXY&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also according to Wikipedia, and other sources, they are hot, up to 1000 degrees Celsius, and consist of gasses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This makes me wonder, &lt;strong&gt;why do those hot gasses not ascend up into the atmosphere?&lt;/strong&gt; This is what hot air does, so there must be something very special about theses gasses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Now, I know that C02 and CO are heavier than air, but at 1000 degrees?&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="15183" LastActivityDate="2019-02-15T18:35:57.990" Title="Why are pyroclastic flows ground-bound?" Tags="|volcanology|pyroclastic-flows|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16256" PostTypeId="1" AcceptedAnswerId="16260" CreationDate="2019-02-15T16:09:32.777" Score="10" ViewCount="3458" Body="&lt;p&gt;I did not find any seamounts as close as 100 m to the water surface (100m from the mean surface level at the location of the mountain) that are not part of any Exclusive Economic Zone (EEZ.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do any such seamounts exist?&lt;/p&gt;&#xA;" OwnerUserId="15185" LastEditorUserId="1099" LastEditDate="2019-02-16T03:45:03.823" LastActivityDate="2019-02-16T03:45:03.823" Title="Are there seamounts as close as 100 m to the water surface and not inside any Exclusive Economic Zone?" Tags="|oceanography|geography|mapping|cartography|ocean-ridge|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16257" PostTypeId="2" ParentId="16256" CreationDate="2019-02-15T16:58:55.233" Score="13" Body="&lt;p&gt;Checking the &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_submarine_volcanoes&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia page&lt;/a&gt; on underwater volcanoes and listing them by height, I think the best candidate is &lt;a href=&quot;https://en.wikipedia.org/wiki/Vema_Seamount&quot; rel=&quot;noreferrer&quot;&gt;Vema Seamount&lt;/a&gt;. Vema Seamount is in international waters and its shallowest point is at 11 meters from the surface. It is so shallow that it represents a navigation hazard.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2019-02-15T16:58:55.233" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16258" PostTypeId="2" ParentId="16255" CreationDate="2019-02-15T18:35:57.990" Score="2" Body="&lt;p&gt;Volcanic plumes and pyroclastic flows are two behaviours of basically the same thing. A volume of hot gasses and &lt;a href=&quot;https://en.wikipedia.org/wiki/Tephra&quot; rel=&quot;nofollow noreferrer&quot;&gt;tephra&lt;/a&gt; (a.k.a. a mix of ash, pumice, and volcanic rocks of different sizes). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the gas is hot enough and the tephra content is light enough the mix will be buoyant and it will rise as a volcanic plume. On the other hand if gas is too cold to support the plume, or the weight of the tephra is too heavy. It will collapse and rush downhill as a pyroclastic flow. That is referred to as a &quot;Fountain collapse&quot;, and is the most common cause of pyroclastic flows.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is why the are also referred as density or gravity currents.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-02-15T18:35:57.990" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16260" PostTypeId="2" ParentId="16256" CreationDate="2019-02-15T22:21:19.940" Score="18" Body="&lt;p&gt;Yes, there are many. According to the seafloor topographic data of &lt;a href=&quot;https://www.ngdc.noaa.gov/mgg/global/global.html&quot; rel=&quot;noreferrer&quot;&gt;ETOPO&lt;/a&gt; (1 arc second resolution), and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Exclusive_economic_zone&quot; rel=&quot;noreferrer&quot;&gt;Exclusive Economic Zones&lt;/a&gt; (EEZ) &lt;a href=&quot;http://www.marineregions.org/downloads.php&quot; rel=&quot;noreferrer&quot;&gt;database of marineregions.org&lt;/a&gt;. There are at least 157 seafloor features higher than -100 m (closer than 100 m to the sea surface). With that data, I made the following figure that shows:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;ETOPO topographic data&lt;/li&gt;&#xA;&lt;li&gt;All EEZ polygons&lt;/li&gt;&#xA;&lt;li&gt;All 157 -100 m contour lines that are completely or partially outside any EEZ.&lt;/li&gt;&#xA;&lt;li&gt;A red point at the centroid of each contour line (to make even the smaller seamounts visible).&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WFhtf.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WFhtf.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some of them are just a few meters below sea level according to ETOPO.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But note that with this data we can only see large features. ETOPO resolution is about 2 km. Therefore, a seamount with a sharp summit just above -100 m would probably not show up on ETOPO data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For more information about individual seamounts you can query the &lt;a href=&quot;https://earthref.org/SC/&quot; rel=&quot;noreferrer&quot;&gt;Seamount Catalog&lt;/a&gt; of &lt;a href=&quot;https://earthref.org/&quot; rel=&quot;noreferrer&quot;&gt;EarthRef.org&lt;/a&gt;. There you can find high resolution multibeam seafloor topographic data for many seamounts, there are more than 1,800 seamounts in the catalog so far.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, for Vema seamount that was mention by @arkaia and that corresponds to the point just West of South Africa in my figure, you can find data like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/z9w3Q.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/z9w3Q.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-16T00:05:35.173" LastActivityDate="2019-02-16T00:05:35.173" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16261" PostTypeId="1" AcceptedAnswerId="16262" CreationDate="2019-02-15T23:08:59.340" Score="1" ViewCount="33" Body="&lt;p&gt;This may seem an obvious question but I am unable to understand what the technical term for the surrounding water of an environment is, specifically surrounding a person/animal within that environment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Humidity:&lt;/strong&gt; This seems like the most obvious answer but 100% humidity still refers to air and as far as I understand doesn't apply to environments like the bottom of the ocean or a pond.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a single term that describes the water content surrounding a person or animal?&lt;/p&gt;&#xA;" OwnerUserId="15188" LastActivityDate="2019-02-16T00:01:57.827" Title="What is the technical term for the amount of water within the surrounding enviornment?" Tags="|ecology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16262" PostTypeId="2" ParentId="16261" CreationDate="2019-02-16T00:01:57.827" Score="0" Body="&lt;p&gt;What is capped at 100% is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Humidity#Relative_humidity&quot; rel=&quot;nofollow noreferrer&quot;&gt;relative humidity&lt;/a&gt;, that describes the degree of water saturation of air. Relative humidity only consider the water that is dissolved in the air, not all the water that exists in a given volume of air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You are interested in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mixing_ratio&quot; rel=&quot;nofollow noreferrer&quot;&gt;mixing ratio&lt;/a&gt; between air and water, which is referred to as &lt;a href=&quot;https://en.wikipedia.org/wiki/Humidity#Specific_humidity&quot; rel=&quot;nofollow noreferrer&quot;&gt;specific humidity&lt;/a&gt;. Specific humidity is the ratio of the mass of water to the total mass of the moist air parcel.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That water, usually refers only to the one dissolved in the air parcel. However, it can easily be extended to include water droplets and other bodies of water. But that approach will require that you define an arbitrary volume over to which compute the mixing ratio, because you won't be able to treat this as a continuum problem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For instance you can compute the mean mixing ratio between air and water on a 10 meters sphere around your object of interest. Then, the more water there is within that volume, the higher will be your mixing ratio. For example, if a person is swimming 10 m deep, the mixing ratio would be almost 1. And if the same person is in the desert more than 10 m away from any water body, the mixing ration will be close to zero (not cero because all the water in the person's body and what is always in the air).&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-02-16T00:01:57.827" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16265" PostTypeId="2" ParentId="13918" CreationDate="2019-02-16T12:26:12.417" Score="7" Body="&lt;p&gt;Lake breezes(similar to sea breezes) are fundamentally a feature of mesoscale meteorology and the peer reviewed reference &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/1520-0477%281997%29078%3C1135%3ASLDBSO%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Small Lake Daytime Breezes:&#xA;Some Observational and&#xA;Conceptual Evaluations&lt;/a&gt; details both the observational studies of lake breezes and the conceptual understanding behind the formation of the lake breeze.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since OP's question is &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How big does a body of water need to have a sea breeze?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The answer according to this book &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/0860081443&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate in a small area&lt;/a&gt; which is one of the references in the first reference is that lake breezes have been observed in lakes with a width of about 4 kms(&lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Suwa&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Suwa, Japan &lt;/a&gt;) and a width of 10 kms (&lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Constance&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Constance, Switzerland&lt;/a&gt;). The lake breeze reached a speed of 2 m &lt;span class=&quot;math-container&quot;&gt;$s^{-1}$&lt;/span&gt; in the case of Lake Suwa and slightly greater speed in the case of Lake Constance. But because both of these lakes are orographic lakes the presence of thermally induced upslope flows (diurnal heating and consequent upslope flows during the day)  can interfere with the formation of lake breeze. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further observational studies carried much later for the following lakes  &lt;a href=&quot;https://en.wikipedia.org/wiki/El_Dorado_Lake&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake El Dorado &lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Okeechobee&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Okeechobee&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Winnipeg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Winnipeg&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Eufaula_Lake&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Eufaula&lt;/a&gt; have reported lake breeze speed values in the range of 2-4 m &lt;span class=&quot;math-container&quot;&gt;$s^{-1}$&lt;/span&gt;. One must remember that these lakes are much larger in size but in essence the numbers capture the range of the lake breeze values. These observations had been obtained as a result of measurements carried out over a period of few months and over different weather conditions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The upper range for the lake breeze is around 6 m &lt;span class=&quot;math-container&quot;&gt;$s^{-1}$&lt;/span&gt; and any lake having a width of less than 2 km is likely to have an undetectable lake breeze. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the physics behind the lake breeze formation in essence is similar to the physics behind the sea breeze formation. A pressure gradient(density gradient) is created between the land and the lake and this gradient is primarily established in the lower troposphere. Greater the inland sensible heat flux greater the value of the pressure gradient. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following URL shows satellite images of different stages of formation of a lake breeze during the day - &lt;a href=&quot;https://www.weather.gov/bgm/WeatherInActionLakeShadowBreeze&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Breeze Satellite Imagery&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In regards to the second question I believe &lt;a href=&quot;https://en.wikipedia.org/wiki/Steam_devil&quot; rel=&quot;nofollow noreferrer&quot;&gt;steam devils&lt;/a&gt; are mesoscale vortices that have been observed to form over lakes. These vortices are no more than 50-200 meters wide and can develop in the absence of any major synoptic scale forcing. But the surface area of the lakes have to be in the range of &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Lakes&quot; rel=&quot;nofollow noreferrer&quot;&gt;Great Lakes of North America &lt;/a&gt; in order for the strong surface heat fluxes to play a role in mesoscale vortex development. The following peer reviewed reference provides observational and modeling studies of steam devils- &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/1520-0493%281988%29116%3C1374%3AMSVEWA%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mesoscale spiral vortex embedded within a lake&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-02-17T00:26:57.587" LastActivityDate="2019-02-17T00:26:57.587" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="16266" PostTypeId="1" AcceptedAnswerId="16346" CreationDate="2019-02-16T13:50:41.810" Score="7" ViewCount="170" Body="&lt;p&gt;I read in Walter Alvarez' book T. Rex and the Crater of Doom&#xA;that the Earth's collision with the large meteor leading to the K-T extinction catalyzed the reaction of atmospheric oxygen and nitrogen molecules to form nitric oxide, which in turn formed highly corrosive nitric acid when combined with water. In addition the impact is thought to have volatilized huge amounts of sulfur contained in anhydrite, which in turn formed sulfuric acid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/2760/are-there-any-metal-anomalies-other-than-iridium-in-the-k-pg-boundary?rq=1&quot;&gt;This&lt;/a&gt; question refers to a thickness of  &lt;span class=&quot;math-container&quot;&gt;$\pu{1.8m}$&lt;/span&gt; for the section where iridium could be detected in the K-T boundary, suggesting that the resolution may be too low to note the effects of acid rain following the collision. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there evidence in the geological record of the formation of these acid species thought to be associated with the collision, say from deposits and/or effects of the ensuing acid rain?&lt;/p&gt;&#xA;" OwnerUserId="15191" LastEditorUserId="15191" LastEditDate="2019-02-27T07:22:54.373" LastActivityDate="2019-02-27T07:22:54.373" Title="Signatures of acid rain at KT boundary" Tags="|paleontology|meteorite|mass-extinction|cretaceous|acid-rain|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16268" PostTypeId="2" ParentId="13306" CreationDate="2019-02-17T01:00:46.853" Score="6" Body="&lt;p&gt;You cannot leave &quot;temperature outside&quot;, as temperature is the key factor to know if the balloon would pop or not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's set up some assumptions about the problem so we can calculate something:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The gas inside the balloon behave according the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ideal_gas_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;ideal gas law&lt;/a&gt;: &lt;span class=&quot;math-container&quot;&gt;$PV=nRT$&lt;/span&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;That the balloon can hold a differential pressure of 30 mmHg (=4000 Pa) as found in &lt;a href=&quot;https://www.youtube.com/watch?v=fwh-i0WB_bQ&quot; rel=&quot;nofollow noreferrer&quot;&gt;this experiment&lt;/a&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;That the maximum volume of a balloon is 0.015 m&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt; as suggested &lt;a href=&quot;https://answers.yahoo.com/question/index?qid=20090704001445AA47gCq&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;The balloon starts filled to its maximum size.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;With this we can calculate how many moles of gas the balloon can hold when inflated in space at a given temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the temperature I'll assume it will be something between the temperature of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cosmic_microwave_background&quot; rel=&quot;nofollow noreferrer&quot;&gt;cosmic microwave background radiation&lt;/a&gt; (if it is on the shade) of ~2.7 K (-270 °C), and the temperature that a black body that is illuminated by the Sun near Earth's orbit, which would be about 278 K (about 5°C). This assumes that the balloon is small enough so that heat can be transferred efficiently by diffusion from one side to the other (the calculation of this value can be seen in the code at the end and is based on the equation &lt;a href=&quot;https://en.wikipedia.org/wiki/Effective_temperature#Surface_temperature_of_a_planet&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With this range of temperatures we can find the volume of the balloon on the surface assuming a final pressure of 1 atm (101325 Pa) and a temperature of 15 °C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We get the following relationship:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pkE7k.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pkE7k.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In red are the final volumes for which the balloon would explode and in blue when it wouldn't. The critical temperature in between is -262 °C (~11 K).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, &lt;strong&gt;the balloon would not pop as long as its initial temperature is higher than -262 °C&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This also assume that the hottest point in the trajectory is the surface. This means that we are assuming that the balloon will pass through the &lt;a href=&quot;https://en.wikipedia.org/wiki/Thermosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;thermosphere&lt;/a&gt; fast enough to do not reach thermal equilibrium with it (it can be extremely hot). This could be a reasonable assumption given the very low density of that layer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course this also assume the rubber of the balloon do not change its properties with temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, only once you specify the height at which you release the balloon and its initial temperature, then you can start calculating fall time. And that will be more difficult, because even if you assume the balloon is at free fall terminal velocity the whole time,  this velocity will change along the fall line due to changes air density and balloon size. Air density and balloon size will affect air resistance and, therefore, terminal free fall speed. You will need to do an analytical or numerical integration of the fall to get the total time.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Matlab code used to generate the above figure&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;R=8.3145;%Ideal gas constant [J/mol K]&#xA;&#xA;Lsol=3.828e26;%Solar luminosity [W]&#xA;Dsol=149597870700;%Distance earth-sun [m]&#xA;sigma=5.670373e-8;%Stefan–Boltzmann constant [W m^-2 K^-4]&#xA;alpha=0;%albedo&#xA;epsilon=1;%emissivity&#xA;% Temperature of a black body (rotating or small enough to transfer heat efficiently from the illuminated side to the dark side)&#xA;Tbb=((1/4)*((Lsol*(1-alpha))/(4*pi*epsilon*sigma*(Dsol^2))))^(1/4);&#xA;&#xA;% Temperature range&#xA;T=linspace(2.7,Tbb,1000);%[K]&#xA;Vmax=0.015;% Exploding volume [m³]&#xA;Pspace=4000;%Maximum pressure hold by the balloon [Pa]&#xA;n=Pspace*Vmax./(R*T);% number of moles that the balloon would hold&#xA;Patm=101325;% Atmospheric pressure [Pa]&#xA;Tsurface=15+273.15; % temperature at the surface [K]&#xA;&#xA;% Volume once back on earth surface&#xA;Vfin=n*R*Tsurface./Patm;&#xA;&#xA;explodeIdx=Vfin&amp;gt;Vmax;&#xA;Tlim=find(explodeIdx,1,'last');&#xA;&#xA;figure('Color','w');&#xA;hold on&#xA;box on&#xA;plot(Vfin(~explodeIdx)*1000,T(~explodeIdx)-273.15,'b','LineWidth',2);&#xA;plot(Vfin(explodeIdx)*1000,T(explodeIdx)-273.15,'r','LineWidth',2);&#xA;plot([0 max(Vfin)]*1000,[1 1]*T(Tlim)-273.15,':r','LineWidth',2)&#xA;ylim([0 max(T)]-273.15);&#xA;&#xA;xlabel('Final volume [liters]')&#xA;ylabel('Initial temperature [°C]')&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-24T01:45:12.187" LastActivityDate="2019-02-24T01:45:12.187" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16269" PostTypeId="1" CreationDate="2019-02-17T03:37:19.767" Score="8" ViewCount="199" Body="&lt;p&gt;This is my first post on StackExchange and I would like to ask a question:&#xA;Is water actually blue or is that just the reflection of the sky?&lt;/p&gt;&#xA;" OwnerDisplayName="user15196" LastActivityDate="2019-02-21T11:13:19.590" Title="Is water actually blue or is it transparent?" Tags="|water|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16270" PostTypeId="2" ParentId="16269" CreationDate="2019-02-17T04:19:20.313" Score="6" Body="&lt;p&gt;It is blue. But white light needs to cross a long distance through the water to actually get the blue tint.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/13240/11908&quot;&gt;This related question&lt;/a&gt; explains it for ice, but for water it is pretty much the same story.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.scientificamerican.com/article/why-does-the-ocean-appear/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt;, mentioned by &lt;a href=&quot;https://earthscience.stackexchange.com/users/6298/jeopardytempest&quot;&gt;@JeopardyTempest&lt;/a&gt; in the comments of the answer to the above question, tackles the case of the oceans. There it says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The ocean looks blue because red, orange and yellow (long wavelength&#xA;  light) are absorbed more strongly by water than is blue (short&#xA;  wavelength light). So when white light from the sun enters the ocean,&#xA;  it is mostly the blue that gets returned.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="6298" LastEditDate="2019-02-21T11:13:19.590" LastActivityDate="2019-02-21T11:13:19.590" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16271" PostTypeId="1" AcceptedAnswerId="16273" CreationDate="2019-02-17T08:55:51.623" Score="2" ViewCount="99" Body="&lt;p&gt;I want night microphysics RGB composite from EUMETSAT. I'm looking for archived images. I tried finding them on EUMETSAT's data center page. Data from different channels of SEVIRI is available but composites are not. Any help will be greatly appreciated. &lt;/p&gt;&#xA;" OwnerUserId="15197" LastEditorUserId="11908" LastEditDate="2019-03-11T21:11:48.573" LastActivityDate="2019-03-11T21:11:48.573" Title="Where can I find archived night microphysics images from EUMETSAT? I" Tags="|climate|remote-sensing|weather-satellites|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16272" PostTypeId="1" CreationDate="2019-02-17T16:26:57.833" Score="1" ViewCount="11676" Body="&lt;p&gt;I've read many papers about Grand Solar Minimums and Glassberg Minimums, known to science for a very long time, and studied and monitored with many public funds. History shows solar activity is the main driver of our climate, and additional contributors like orbital parameters and geomagnetic field intensity are also still connected to how much energy the Earth gets from the Sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The present trend towards a Grand Solar Minimum was predicted since the '70s and we already see signs of it in solar activity and in our climate, yet it seems to have consistently been ignored by climate experts, by our governments, and by the media. Why is this the case?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Solar activity reconstructed from tree rings and Carbon-14 data:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/z1jwO.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/z1jwO.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Some pertinent studies regarding such Minimums include the iconic paper &lt;a href=&quot;https://pdfs.semanticscholar.org/b7c0/87fa74f6855443e428db19007574eaf47eeb.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;J.A.Eddy, 1976: The Maunder Minimum&lt;/a&gt; and &lt;a href=&quot;https://www.researchgate.net/publication/266799418_Prediction_of_Solar_Activity_from_Solar_Background_Magnetic_Field_Variations_in_Cycles_21-23&quot; rel=&quot;nofollow noreferrer&quot;&gt;this 2014 paper by Valentina Zharkova on predicting the next solar cycles&lt;/a&gt;, among many others.)  &lt;/p&gt;&#xA;" OwnerUserId="14761" LastEditorUserId="6298" LastEditDate="2019-02-21T07:49:08.510" LastActivityDate="2019-02-21T09:42:17.060" Title="Why do climate experts from the UN/IPCC rarely mention Grand Solar Minimum?" Tags="|climate-change|paleoclimatology|solar-terrestrial-physics|" AnswerCount="2" CommentCount="50" ContentLicense="CC BY-SA 4.0" />
  <row Id="16273" PostTypeId="2" ParentId="16271" CreationDate="2019-02-17T16:55:11.497" Score="2" Body="&lt;p&gt;I think only the &lt;strong&gt;Day&lt;/strong&gt; microphysics RGB composite is a standard EUMETSAT product. However, &lt;strong&gt;the night microphysics RGB is available from other data portals&lt;/strong&gt; like the &lt;a href=&quot;http://eumetrain.org/eport.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ePort&lt;/a&gt; by &lt;a href=&quot;http://eumetrain.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Eumetrain.org&lt;/a&gt;. There you can access and visualize current or archive night microphysics RGB composites. The &lt;a href=&quot;http://eumetrain.org/ePort_MapViewer/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Java version&lt;/a&gt; works better for me, this is an screenshot of how it looks:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iyhns.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iyhns.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-02-17T16:55:11.497" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16274" PostTypeId="2" ParentId="16272" CreationDate="2019-02-17T17:39:07.040" Score="79" Body="&lt;p&gt;The IPCC do mentions solar minimums and maximums, as part of extremely careful treatment they do of the reconstructions and predictions for the changes in solar irradiance. &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter08_FINAL.pdf&quot; rel=&quot;noreferrer&quot;&gt;The Assessment Report 5, Working Group 1, Chapter 8&lt;/a&gt;, have a whole section (~4 pages) dealing with solar irradiances.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the IPCC don't mention grand solar maximums/minumums that often, is because the research in the area have shown that solar minimums and maximums have smaller impact in climate than other factors. Therefore, such factors deserve more attention, like Greenhouse gases or land use changes. These factors deserve more attention both because they have a greater impact on climate and because we can do something about them. When it comes to solar activity we can't do much anyway.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The work of the IPCC is to combine the research of the whole scientific community, their conclusions are not based in the result of a single study but in the combination of pretty much all of them. Some studies could be contradictory, so instead of cherry-picking what suits them, they compare and combine all the studies to have the most reliable answers and a good idea of the uncertainties. If predictions of multiple models differ a lot it means uncertainties are large. If they all give the same result, we can be a bit more confident about it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, the figure 8.11 compares the reconstruction of solar irradiance between years 1750 and 2000 from six studies:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Boi8z.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Boi8z.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see how the &lt;a href=&quot;https://en.wikipedia.org/wiki/Dalton_Minimum&quot; rel=&quot;noreferrer&quot;&gt;Dalton minimum&lt;/a&gt; shows up around 1810-1820, but the total solar irradiance change is rather small (less than 1 W for over a total of 1360 W).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here some excerpts from the IPCC reports that are relevant to this question, and where solar minimums are mention and considered in the wider context of climatic forcing (text between square brackets were added by me for clarification):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Page 662:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Satellite observations of total solar irradiance (TSI) changes from&#xA;  1978 to 2011 show that the most recent solar cycle minimum was lower&#xA;  than the prior two. This very likely led to a small negative RF [Radiative Forcing] of&#xA;  –0.04 (–0.08 to 0.00) W m&lt;span class=&quot;math-container&quot;&gt;$^{–2}$&lt;/span&gt; between 1986 and 2008. The best&#xA;  estimate of RF due to TSI changes representative&#xA;  for the 1750 to 2011 period is 0.05 (to 0.10) W  m&lt;span class=&quot;math-container&quot;&gt;$^{–2}$&lt;/span&gt;. This is&#xA;  substantially smaller than the AR4 estimate due to the addition of the&#xA;  latest solar cycle and inconsistencies in how solar RF has been&#xA;  estimated in earlier IPCC assessments. There is very low confidence&#xA;  concerning future solar forcing estimates, but there is high&#xA;  confidence that the TSI RF variations will be much smaller than the&#xA;  projected increased forcing due to GHG during the forthcoming decades.&#xA;  {8.4.1, Figures 8.10, 8.11}&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Page 690 (explicit mentions of grand solar minimums):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;8.4.1.3 Attempts to Estimate Future Centennial Trends of Total Solar Irradiance&lt;/strong&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Cosmogenic isotope and sunspot data (Rigozo et al., 2001;&#xA;  Solanki and Krivova, 2004; Abreu et al., 2008) reveal that currently&#xA;  the Sun is in a grand activity maximum [a.k.a. &lt;strong&gt;grand solar maximum&lt;/strong&gt;] that began about 1920 (20th&#xA;  century grand maximum). However, SC [solar cycle] 23 showed an activity decline not&#xA;  previously seen in the satellite era (McComas et al., 2008; Smith and&#xA;  Balogh, 2008; Russell et al., 2010). Most current estimations suggest&#xA;  that the forthcoming solar cycles will have lower TSI [Total Solar Irradiation] than those for&#xA;  the past 30 years (Abreu et al., 2008; Lockwood et al., 2009; Rigozo&#xA;  et al., 2010; Russell et al., 2010). Also there are indications that&#xA;  the mean magnetic field in sunspots may be diminishing on decadal&#xA;  level. A linear expansion of the current trend may indicate that of&#xA;  the order of half the sunspot activity may disappear by about 2015&#xA;  (Penn and Livingston, 2006). These studies only suggest that the Sun&#xA;  may have left the 20th century &lt;strong&gt;grand [solar] maximum&lt;/strong&gt; and not that it is&#xA;  entering another &lt;strong&gt;grand [solar] minimum&lt;/strong&gt;. But other works propose a &lt;strong&gt;grand [solar]&#xA;  minimum&lt;/strong&gt; during the 21st century, estimating an RF within a range of&#xA;  -0.16 to 0.12 W m&lt;span class=&quot;math-container&quot;&gt;$^{–2}$&lt;/span&gt; between this future minimum and the present-day TSI (Jones et al., 2012). However, much more evidence is needed and at&#xA;  present there is very low confidence concerning future solar forcing&#xA;  estimates.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Nevertheless, even if there is such decrease in the solar&#xA;  activity, there is a high confidence that the TSI RF variations will&#xA;  be much smaller in magnitude than the projected increased forcing due&#xA;  to GHG (see Section 12.3.1).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Summarizing, the IPCC consider solar irradiance variations, the timing of solar minimums and maximums. However, it consider also many other factors that also affect Earth's energy budget. Then, they do predictions based on the combined effect of all these factors. In contrast, some people tend to focus on just one factor (as solar activity) and erroneously assume that it will dominate over all the others.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the particular case of solar activity, as you can see in the cites above. The &lt;strong&gt;IPCC acknowledge the possible occurrence of a solar minimum in the future, but combining all the models they conclude that there is a high confidence that its effects will be much smaller in magnitude than the projected increased forcing due greenhouse gases&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Part of the reason your question might not be well received is because it starts from an assumption that is false: &quot;climate experts from the UN/IPCC never mention Grand Solar Minimum&quot;. They do mention it, and if you follow the references in the IPCC you will find plenty of discussion about Dalton, Maunder and older Grand Solar Minimums. And part of that discussion is to estimate the real impact that those events can have in Earth's climate. Then the IPCC get those estimates and figure out how they interplay with the many other factors that conjugate to determine current and future Earth's climate.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="725" LastEditDate="2019-02-21T09:42:17.060" LastActivityDate="2019-02-21T09:42:17.060" CommentCount="19" ContentLicense="CC BY-SA 4.0" />
  <row Id="16275" PostTypeId="2" ParentId="16272" CreationDate="2019-02-17T18:15:11.870" Score="40" Body="&lt;p&gt;I think the main question has already been answered. But I would like to add to the fallacy that:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;History shows solar activity is the main driver of our climate, among other factors.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The Sun is undoubtedly the main source of energy for the planet and its climate. However, variations in solar activity are not the main cause of variations in climate. The main drivers are the &quot;other factors&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some examples of that are:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Faint_young_Sun_paradox&quot; rel=&quot;noreferrer&quot;&gt;Faint young Sun paradox&lt;/a&gt;: The climate on earth has remained in the range that allows the existence of liquid water during billions of years despite large changes in the luminosity of the sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;noreferrer&quot;&gt;Milankovitch cycles&lt;/a&gt;: The cycles that control the ice ages that have dominated the planet during the last million years are not due to changes in solar activity, but to changes in the orbit and orientation of the Earth.&lt;/p&gt;&#xA;" OwnerUserId="15199" LastActivityDate="2019-02-17T18:15:11.870" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="16276" PostTypeId="2" ParentId="14708" CreationDate="2019-02-17T19:03:29.283" Score="1" Body="&lt;p&gt;Commenter Universal Learner points out &quot;Currently NOAA says there is only one ocean&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://oceanservice.noaa.gov/facts/howmanyoceans.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://oceanservice.noaa.gov/facts/howmanyoceans.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and &quot;At the comments of the question I linked you can read a great: &quot;I once heard a lovely description of the world's seas (by a polar scientist) as &quot;One ocean with three big estuaries&quot; ;-) &quot;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;While there is only one global ocean, the vast body of water that&#xA;  covers 71 percent of the Earth is geographically divided into distinct&#xA;  named regions. The boundaries between these regions have evolved over&#xA;  time for a variety of historical, cultural, geographical, and&#xA;  scientific reasons.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Historically, there are four named oceans: the Atlantic, Pacific,&#xA;  Indian, and Arctic. However, most countries - including the United&#xA;  States - now recognize the Southern (Antarctic) as the fifth ocean.&#xA;  The Pacific, Atlantic, and Indian are known as the three major oceans.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The Southern Ocean is the 'newest' named ocean. It is recognized by&#xA;  the U.S. Board on Geographic Names as the body of water extending from&#xA;  the coast of Antarctica to the line of latitude at 60 degrees South.&#xA;  The boundaries of this ocean were proposed to the International&#xA;  Hydrographic Organization in 2000. However, not all countries agree on&#xA;  the proposed boundaries, so this has yet to be ratified by members of&#xA;  the IHO. The U.S. is a member of the IHO, represented by the NOS&#xA;  Office of Coast Survey.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And they have a graphic saying 1 world ocean.  Historically 4 basins.  Now 5 basins. And that the boundaries aren't agreed upon by all countries. Though that text refers to a basin as an ocean, so their terminology doesn't quite match their graphic. &lt;/p&gt;&#xA;" OwnerUserId="5960" LastActivityDate="2019-02-17T19:03:29.283" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16281" PostTypeId="1" CreationDate="2019-02-18T07:20:15.563" Score="1" ViewCount="1901" Body="&lt;p&gt;What exactly is done to classify minerals in Earth Sciences such as Geology? How can it be known if one mineral is the same as another if they should be visually different?&lt;/p&gt;&#xA;" OwnerDisplayName="user15196" LastEditorUserId="6298" LastEditDate="2019-02-21T07:12:45.853" LastActivityDate="2019-02-21T07:12:45.853" Title="How are minerals classified?" Tags="|mineralogy|minerals|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16282" PostTypeId="2" ParentId="4897" CreationDate="2019-02-18T08:45:06.977" Score="-1" Body="&lt;p&gt;Here is the official file &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;fdf_name=&quot;2d_ci7m_gf.ifdf&quot;;&#xA;fdf_description=&quot;2D Card Image 7 multi-horizon export (XY in meters)&quot;;&#xA;data_struct=header_data;&#xA;header_length=by_header;&#xA;sort_order=by_horizon;&#xA;num_header_cards=2;&#xA;begin_of_header_on=false;&#xA;end_of_header_on=false;&#xA;begin_of_data_on=false;&#xA;end_of_data_on=true;&#xA;end_of_data=&quot;EOD&quot;;&#xA;end_of_data_scol=1;&#xA;end_of_data_ecol=4;&#xA;end_of_data_pos=after_last_card;&#xA;profile_label_on=true;&#xA;profile_label=&quot;PROFILE&quot;;&#xA;profile_label_scol=1;&#xA;profile_label_ecol=7;&#xA;profile_label_cnum=1;&#xA;profile_name_on=true;&#xA;profile_name_scol=9;&#xA;profile_name_ecol=28;&#xA;profile_name_cnum=1;&#xA;profile_description_on=true;&#xA;profile_description_scol=40;&#xA;profile_description_ecol=79;&#xA;profile_description_cnum=1;&#xA;type_label_on=true;&#xA;type_label=&quot;TYPE&quot;;&#xA;type_label_scol=30;&#xA;type_label_ecol=33;&#xA;type_label_cnum=1;&#xA;profile_type_on=true;&#xA;profile_type_scol=35;&#xA;profile_type_ecol=35;&#xA;profile_type_cnum=1;&#xA;posting_color_on=true;&#xA;posting_color_scol=37;&#xA;posting_color_ecol=38;&#xA;posting_color_cnum=1;&#xA;contact_symbol_on=false;&#xA;line_label_on=false;&#xA;line_name_on=false;&#xA;line_number_on=false;&#xA;line_type_on=false;&#xA;survey_name_on=false;&#xA;snap_label_on=true;&#xA;snap_label=&quot;SNAPPING PARAMETERS&quot;;&#xA;snap_label_scol=1;&#xA;snap_label_ecol=19;&#xA;snap_label_cnum=2;&#xA;snap_position_on=true;&#xA;snap_position_scol=21;&#xA;snap_position_ecol=21;&#xA;snap_position_cnum=2;&#xA;snap_window_on=true;&#xA;snap_window_scol=23;&#xA;snap_window_ecol=27;&#xA;snap_window_cnum=2;&#xA;event_picked_on=true;&#xA;event_picked_scol=29;&#xA;event_picked_ecol=29;&#xA;event_picked_cnum=2;&#xA;format_file_name_on=true;&#xA;format_file_name_scol=81;&#xA;format_file_name_ecol=96;&#xA;format_file_name_cnum=1;&#xA;xy_units_on=true;&#xA;xy_units_scol=98;&#xA;xy_units_ecol=99;&#xA;xy_units_cnum=1;&#xA;z_units_on=true;&#xA;z_units_scol=101;&#xA;z_units_ecol=102;&#xA;z_units_cnum=1;&#xA;x_coordinate_on=true;&#xA;x_coordinate_scol=1;&#xA;x_coordinate_ecol=16;&#xA;x_coordinate_units=meter;&#xA;x_coordinate_type=exponent;&#xA;x_coordinate_decimal=8;&#xA;y_coordinate_on=true;&#xA;y_coordinate_scol=17;&#xA;y_coordinate_ecol=32;&#xA;y_coordinate_units=meter;&#xA;y_coordinate_type=exponent;&#xA;y_coordinate_decimal=8;&#xA;latitude_on=false;&#xA;longitude_on=false;&#xA;time_on=true;&#xA;time_scol=39;&#xA;time_ecol=47;&#xA;time_units=mili_second;&#xA;time_type=floating_points;&#xA;time_decimal=2;&#xA;seismic_trace_number_on=true;&#xA;seismic_trace_number_scol=68;&#xA;seismic_trace_number_ecol=72;&#xA;seismic_trace_number_type=integer;&#xA;seismic_trace_number_decimal=0;&#xA;shot_point_number_on=true;&#xA;shot_point_number_scol=48;&#xA;shot_point_number_ecol=57;&#xA;shot_point_number_type=floating_points;&#xA;shot_point_number_decimal=2;&#xA;cdp_on=true;&#xA;cdp_scol=58;&#xA;cdp_ecol=67;&#xA;cdp_type=floating_points;&#xA;cdp_decimal=2;&#xA;amplitude_on=true;&#xA;amplitude_scol=73;&#xA;amplitude_ecol=86;&#xA;amplitude_type=exponent;&#xA;amplitude_decimal=7;&#xA;attribute_1_on=false;&#xA;attribute_2_on=false;&#xA;attribute_3_on=false;&#xA;dat_profile_name_on=false;&#xA;dat_profile_type_on=false;&#xA;dat_line_name_on=true;&#xA;dat_line_name_scol=90;&#xA;dat_line_name_ecol=131;&#xA;dat_line_number_on=false;&#xA;dat_line_type_on=true;&#xA;dat_line_type_scol=88;&#xA;dat_line_type_ecol=89;&#xA;dat_survey_name_on=false;&#xA;dat_contact_symbol_on=true;&#xA;dat_contact_symbol_scol=36;&#xA;dat_contact_symbol_ecol=38;&#xA;dat_segment_id_on=true;&#xA;dat_segment_id_scol=33;&#xA;dat_segment_id_ecol=35;&#xA;dat_horizon_name_on=false;&#xA;dat_fault_name_on=true;&#xA;dat_fault_name_scol=132;&#xA;dat_fault_name_ecol=151;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="15217" LastEditorUserId="11908" LastEditDate="2019-02-18T16:33:45.353" LastActivityDate="2019-02-18T16:33:45.353" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16283" PostTypeId="2" ParentId="16281" CreationDate="2019-02-18T09:33:22.920" Score="0" Body="&lt;p&gt;Minerals are classified as follows:&#xA;Native elements, Sulphides, Sulphosalts, Oxides, Halides, Carbonates, Nitrates, Borates, Phosphates, Sulphates, Tungstates, Silicates I have listed some of the things I know for more details on the classification of minerals follow this [link].&lt;a href=&quot;https://www.britannica.com/science/mineral-chemical-compound/Classification-of-minerals&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15218" LastActivityDate="2019-02-18T09:33:22.920" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16284" PostTypeId="2" ParentId="16281" CreationDate="2019-02-18T13:32:43.550" Score="6" Body="&lt;p&gt;Minerals are defined by chemical composition and crystallography. Dana classification scheme or new Dana classification scheme divides known mineral species in eight broad groups based on primary chemical properties and crystal form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Organic vs inorganic    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Silicates vs non-silicates &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;  Subdivided silicates into smaller groups by crystalline structures&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Metals vs non-metals&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;  Subdivide non-metals into smaller groups&#xA;      metal oxides&#xA;      metal sulfides&#xA;      metal and non-metal acid salts organized by dominant anion (1)(2)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;(1) In chemistry, a salt is an ionic compound that can be formed by the neutralization reaction of an acid and a base.&lt;a href=&quot;https://en.wikipedia.org/wiki/Salt_(chemistry)&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt; Salts are composed of related numbers of cations (positively charged ions) and anions (negative ions) so that the product is electrically neutral (without a net charge). These component ions can be inorganic, such as chloride (Cl−), or organic, such as acetate (CH3CO−2); and can be monatomic, such as fluoride (F−), or polyatomic, such as sulfate (SO2−4).  (&lt;a href=&quot;https://en.wikipedia.org/wiki/Salt_(chemistry)&quot; rel=&quot;nofollow noreferrer&quot;&gt;from wikipedia&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) Some these subgroups represent hypothetical acid-base reactions not actualy seen in nature but modeled after known acid-base reactions. My opinion here is that this approach was used because it was popular theory in chemistry at the time when James Dwight Dana published his work in 1837.       &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are other minerals classfication systems&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) &lt;a href=&quot;https://en.wikipedia.org/wiki/Crystal_system&quot; rel=&quot;nofollow noreferrer&quot;&gt;By crystal system&lt;/a&gt; -triclinic, monoclinic, orthorhombic, tetragonal, hexagonal, and cubic. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) By Cleavage, parting, fracture, and tenacity&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) By mineral hardness&lt;/p&gt;&#xA;&#xA;&lt;p&gt;4) By specific gravity or density&lt;/p&gt;&#xA;&#xA;&lt;p&gt;5) By mineral association (my favorite and often the best way of identifying and unknown mineral especially when the location is known.&lt;/p&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="1149" LastEditDate="2019-02-19T23:46:05.337" LastActivityDate="2019-02-19T23:46:05.337" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16285" PostTypeId="2" ParentId="72" CreationDate="2019-02-18T16:56:59.027" Score="10" Body="&lt;p&gt;From the &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_TS_FINAL.pdf#page=28&quot; rel=&quot;noreferrer&quot;&gt;IPCC Fifth Assessment Report&lt;/a&gt; (2014 / current):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It is extremely likely that human activities caused more than half of the observed increase in global average surface temperature from 1951 to 2010. This assessment is supported by robust evidence from multiple studies  using  different  methods.  In  particular,  the  temperature  trend  attributable to all anthropogenic forcings combined can be more closely constrained in multi-signal detection and attribution analyses. Uncertainties in forcings and in climate models’ responses to those forcings, together  with  difficulty  in  distinguishing  the  patterns  of  temperature  response due to WMGHGs and other anthropogenic forcings, prevent as precise a quantification of the temperature changes  attributable to WMGHGs  and  other  anthropogenic  forcings  individually.  Consistent  with AR4, it is assessed that more than half of the observed increase in global average surface temperature from 1951 to 2010 is very likely due  to  the  observed  anthropogenic  increase  in  WMGHG  concentrations.  WMGHGs  contributed  a  global  mean  surface  warming  likely to  be  between  0.5°C  and  1.3°C  over  the  period  between  1951  and  2010, with the contributions from other anthropogenic forcings likely to be between –0.6°C and 0.1°C and from natural forcings likely to be between –0.1°C and 0.1°C. Together these assessed contributions are consistent  with  the  observed  warming  of  approximately  0.6°C  over  this period (Figure TS.10). {10.3}&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/X3sMX.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/X3sMX.jpg&quot; alt=&quot;&amp;quot;Likely&amp;quot; ranges and midpoints for warming trends 1951-2010&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Observed: temperature measurements&lt;/p&gt;&#xA;&#xA;&lt;p&gt;WMGHG or GHG: Well-mixed greenhouse gases like CO2&lt;/p&gt;&#xA;&#xA;&lt;p&gt;ANT: Sum of GHG and OA&lt;/p&gt;&#xA;&#xA;&lt;p&gt;OA: Other anthropogenic forcings on temperature like aerosols and black carbon&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NAT: Natural variability such as change in solar radiation&#xA;Internal Variability: Estimated lack of knowledge in current earth models&lt;/p&gt;&#xA;" OwnerUserId="13373" LastEditorUserId="13373" LastEditDate="2019-02-26T18:22:48.910" LastActivityDate="2019-02-26T18:22:48.910" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16286" PostTypeId="1" CreationDate="2019-02-18T18:54:09.213" Score="6" ViewCount="490" Body="&lt;p&gt;When the sea level rises, more of the planet's area is watery and less of it is land.  Does this change in surface condition result in a change in global warming, such as a decrease in the net radiation watts that we expect for the globe?  How does this change affect other &quot;forcings&quot; like radiative and water vapor?&lt;/p&gt;&#xA;" OwnerUserId="13373" LastEditorUserId="11908" LastEditDate="2019-03-17T19:42:44.863" LastActivityDate="2019-03-17T19:42:44.863" Title="When sea level rises, does the increased ocean area cause the earth to cool down somewhat?" Tags="|climate-change|sea-level|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="16287" PostTypeId="1" CreationDate="2019-02-18T21:38:26.360" Score="3" ViewCount="63" Body="&lt;p&gt;Recently I read about OceanReef's Nemo's garden, which is growing terrestrial plants underwater inside a dome on the seefloor. I did not found any other company doing it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If it is that good as it is claimed to be (lack of pests and doseases, stable temperature), why did not the technology go large scale in the past years? There were articles about it from 2015 so quite a few years passed since then.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So why didn't the technology went into large-scale commercial use yet and is there any specific reason why noone else seems doing it?&lt;/p&gt;&#xA;" OwnerUserId="15185" LastActivityDate="2019-02-18T21:38:26.360" Title="What are the main obstacles facing large-scale underwater farming?" Tags="|agriculture|sea-floor|" AnswerCount="0" CommentCount="6" ClosedDate="2019-02-19T13:43:13.780" ContentLicense="CC BY-SA 4.0" />
  <row Id="16291" PostTypeId="2" ParentId="16286" CreationDate="2019-02-19T22:01:38.423" Score="6" Body="&lt;p&gt;As you say, land and water &lt;a href=&quot;https://en.wikipedia.org/wiki/Albedo&quot; rel=&quot;nofollow noreferrer&quot;&gt;albedos&lt;/a&gt; are very different. Meaning that a square meter of water, in average, absorbs more energy from the sun than a square meter of land. Also water transfers heat vertically more efficiently than land due to convection and it also affects climate by providing a ready moisture source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, changes in the surface of land vs water do have an impact on climate. However, the change in water surface area due to sea level rise is very small compared with other changes in land/water surfaces. Let's crunch some numbers to see it more clearly...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lets consider a good approximate of the length of the &lt;a href=&quot;https://science.nasa.gov/earth-science/oceanography/living-ocean&quot; rel=&quot;nofollow noreferrer&quot;&gt;global shoreline of 620,000 km&lt;/a&gt; (a precise number is impossible to get due to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Coastline_paradox&quot; rel=&quot;nofollow noreferrer&quot;&gt;coastline paradox&lt;/a&gt;). Now, at current sea level rise of &lt;a href=&quot;https://climate.nasa.gov/vital-signs/sea-level/&quot; rel=&quot;nofollow noreferrer&quot;&gt;3.2 mm/year&lt;/a&gt;, 30 years would mean about 10 cm of sea level rise. If we assume that the typical slope is such that this moves the shoreline also 10 cm forward, the associated area increase would be:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$620000\, \text{km} \times 0.0001\, \text{km} = 62\, \text{km}^2$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And this is negligible compared with other effects like the drying of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Aral_Sea&quot; rel=&quot;nofollow noreferrer&quot;&gt;Aral sea&lt;/a&gt; (~28,000 km&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt;), the construction of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Three_Gorges_Dam&quot; rel=&quot;nofollow noreferrer&quot;&gt;Three Gorges Dam&lt;/a&gt; (1,084 km&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt;), or even the construction of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Palm_Islands&quot; rel=&quot;nofollow noreferrer&quot;&gt;Palm Islands&lt;/a&gt; in Dubai (80 km&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even if our very rough calculation above is multiplied by ten or even one hundred, the contribution of sea level rise would remain small compared with other changes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At a global scale over the last 30 years there was a &lt;a href=&quot;https://www.nature.com/articles/nclimate3111&quot; rel=&quot;nofollow noreferrer&quot;&gt;net increase of 58,000 km&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt; of water surface&lt;/a&gt;, but mostly due to natural processes or large infrastructure projects. Sea level rise played just a very minor role in those changes.  Indeed the following figure from the paper &lt;a href=&quot;https://www.nature.com/articles/nclimate3111&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth's surface water change over the past 30 years&lt;/a&gt; shows changes from land to water in blue and changes from water to land in green:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hTURa.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hTURa.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, what's the effect of this increased water surface area (even if it is not due to sea level rise), that's another question that I won't get into in detail. But in general it will be a warming effect, both because of the lower albedo of water, and because of the warming effect of low clouds. However, the actual effect will depend on where the new water bodies are located; some extra water near the sea wouldn't have the same impact as some extra water in the middle of a desert. &lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="6298" LastEditDate="2019-02-21T07:23:26.277" LastActivityDate="2019-02-21T07:23:26.277" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16294" PostTypeId="1" CreationDate="2019-02-20T01:20:15.967" Score="2" ViewCount="163" Body="&lt;p&gt;I'm interested in doing data visualization projects about mountains.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We have data from &lt;a href=&quot;http://www.peaklist.org/ultras.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.peaklist.org/ultras.html&lt;/a&gt; complied by Aaron Maizlish (Who we tried to contact but not sure of his contact details these days?)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data he was curating contains name, elevation, co-ordinates and Key Saddle.  The key bit of data we're after is the distance from elevation to either key saddle  or sea level to get a very rough outline of shape.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not sure if such data exists or we would have to derive it from some topography database?  Would anyone have any ideas on how we might go about getting said data or access to free topographic data that we may be able to somehow match in?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've attached the below artwork that inspired this project - while we wouldn't necessarily look to get all the shape types here, it would be nice to have some different natural shapes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The idea being somewhere in between pure Art &amp;amp; pure geography &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks, Damian.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MwLTV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MwLTV.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15251" LastEditorUserId="15251" LastEditDate="2019-02-21T04:17:33.420" LastActivityDate="2019-03-01T06:30:13.967" Title="mountain database of elevation and distance from saddle (as a proxy for gradient)" Tags="|geography|open-data|geomorphology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16299" PostTypeId="1" CreationDate="2019-02-20T13:58:58.963" Score="4" ViewCount="134" Body="&lt;p&gt;Good day,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do not fully understand the physical mechanism of formation of Rayleigh waves at the free surface. While their derivation is quite clear and obey free-boundary conditions, it is not clear their physical mechanism.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could you please correct me in my discussion. Incident P-wave can transform to reflected P and SV waves. When the angle of incidence of P wave reaches 2nd critical angle, both outgoing P and SV waves propagate along the surface forming Rayleigh wave. So, P-wave by itself can form Rayleigh wave. At the same time, incident SV wave can transform to reflected P and SV waves. When the angle of incidence of SV wave (again) reaches second critical angle - both outgoing P and SV waves propagate along the surface forming Rayleigh wave.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can then Rayleigh wave be formed by interference of both incident P and SV waves on the free surface or Rayleigh waves are formed only separately by incident P or SV waves? Does it mean that right under the epicenter Rayleigh waves cannot form but at some distance from it in order to reach second critical angles?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="12930" LastEditorUserId="12930" LastEditDate="2019-02-20T17:17:26.670" LastActivityDate="2019-02-20T17:17:26.670" Title="Rayleigh waves generation" Tags="|seismology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16306" PostTypeId="2" ParentId="2639" CreationDate="2019-02-21T09:58:40.470" Score="11" Body="&lt;p&gt;This question is from 2014 with answers from 2015. Just to add the point of view of some research that has been done since.&lt;/p&gt;&#xA;&lt;p&gt;In essence, new calculations show that NCS (natural climate solutions: a combination of land management, forestation, etc):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;...can provide over&#xA;one-third of the cost-effective climate mitigation needed between now&#xA;and 2030 to stabilize warming to below 2 °C.&lt;/p&gt;&#xA;&lt;p&gt;Source: Griscom et al (2017), &lt;em&gt;Natural climate solutions&lt;/em&gt;, PNAS, &lt;a href=&quot;https://doi.org/10.1073/pnas.1710465114&quot; rel=&quot;noreferrer&quot;&gt;https://doi.org/10.1073/pnas.1710465114&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;However!&lt;/p&gt;&#xA;&lt;p&gt;Turns out that trees, other than sequestering carbon, also emit volatile organic compounds (VOC) that act as greenhouse gases. Therefore, the answer isn't as simple as planting trees.&lt;/p&gt;&#xA;&lt;p&gt;Quoting some recent articles on the subject:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Many scientists applaud the push for expanding forests, but some urge caution. They argue that forests have many more-complex and uncertain climate impacts than policymakers, environmentalists and even some scientists acknowledge. Although trees cool the globe by taking up carbon through photosynthesis, they also emit a complex potpourri of chemicals, some of which warm the planet. The dark leaves of trees can also raise temperatures by absorbing sunlight. Several analyses in the past few years suggest that these warming effects from forests could partially or fully offset their cooling ability.&lt;/p&gt;&#xA;&lt;p&gt;Source: Gabriel Popkin (2019), &lt;em&gt;How much can forests fight climate change?&lt;/em&gt;, Nature, &lt;a href=&quot;http://doi.org/10.1038/d41586-019-00122-z&quot; rel=&quot;noreferrer&quot;&gt;http://doi.org/10.1038/d41586-019-00122-z&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;That doesn’t mean that all forests cool the planet, however. Researchers have known for decades that tree leaves absorb more sunlight than do other types of land cover, such as fields or bare ground. Forests can reduce Earth’s surface albedo, meaning that the planet reflects less incoming sunlight back into space, leading to warming. This effect is especially pronounced at higher latitudes and in mountainous or dry regions, where slower-growing coniferous trees with dark leaves cover light-coloured ground or snow that would otherwise reflect sunlight. Most scientists agree, however, that tropical forests are clear climate coolers: trees there grow relatively fast and transpire massive amounts of water that forms clouds, two effects that help to cool the climate.&lt;/p&gt;&#xA;&lt;p&gt;Source: Gabriel Popkin (2019)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Atmospheric chemist Nadine Unger, then at Yale University in New Haven, Connecticut, conducted one of the first global studies examining one part of this exchange: the influence of volatile organic compounds, or VOCs, emitted by trees. These include isoprene, a small hydrocarbon that can warm the globe in several ways. It can react with nitrogen oxides in the air to form ozone — a potent climate-warming gas when it resides in the lower atmosphere. Isoprene can also lengthen the lifetime of atmospheric methane — another greenhouse gas. Yet isoprene can have a cooling influence, too, by helping to produce aerosol particles that block incoming sunlight.&lt;/p&gt;&#xA;&lt;p&gt;Source: Gabriel Popkin (2019)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Plants take up carbon dioxide and release volatile organic compounds&#xA;(VOCs), in a similar way to how other organisms breathe in oxygen and&#xA;exhale CO2. These VOCs are oxidized in the atmosphere and then&#xA;contribute substantially to the burden of tiny particles suspended in&#xA;the air, which are known as aerosols. Aerosols produced from VOCs are&#xA;known as secondary organic aerosols (SOAs), and affect both air&#xA;quality and Earth’s climate. The total rate of SOA production was&#xA;thought to be the sum of the individual rates associated with the&#xA;oxidation of each VOC. But writing in Nature, McFiggans et al.1 show&#xA;that a more accurate description is needed to improve the&#xA;representation of SOAs in computational models of air quality and&#xA;climate.&lt;/p&gt;&#xA;&lt;p&gt;Fangqun Yu (2019), &lt;em&gt;Atmospheric reaction networks affecting climate are more complex than was thought&lt;/em&gt;, Nature, &lt;a href=&quot;https://doi.org/10.1038/d41586-019-00263-1&quot; rel=&quot;noreferrer&quot;&gt;https://doi.org/10.1038/d41586-019-00263-1&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Sources of the articles:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1073/pnas.1710465114&quot; rel=&quot;noreferrer&quot;&gt;one&lt;/a&gt;; &lt;a href=&quot;https://doi.org/10.1038/d41586-019-00122-z&quot; rel=&quot;noreferrer&quot;&gt;two&lt;/a&gt;; &lt;a href=&quot;https://doi.org/10.1038/d41586-019-00263-1&quot; rel=&quot;noreferrer&quot;&gt;three&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-02-25T22:31:00.850" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16307" PostTypeId="2" ParentId="428" CreationDate="2019-02-21T11:55:53.490" Score="2" Body="&lt;p&gt;The earth produces 20TW[1] of thermal energy from radioactive decay in the mantle. This is the amount of warmth that the earth generates, so it should give us a ballpark idea of how much heat we would need to remove from the earth in order to make an impact on the earth's internal temperature. To summarize the heating situation under earth's crust, the existing heat comes from two sources in ~equal parts: radioactive decay, and leftover heat from the earth's creation[1]. Lots of heat hits the earth from the sun but gets radiated back out; It doesn't really have anything to do with internal temperatures[1].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1] &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_internal_heat_budget&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Earth%27s_internal_heat_budget&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as I can tell from that wikki page:&#xA;Current heat in the earth: ~50% radiation, ~50% leftover&#xA;Internal heat budget: Geothermal Power Consumption + 47TW transferred from the mantle to the crust and beyond[1] - 20TW generated from radiation  = Core cooling rate&#xA;Core cooling rate without geothermal: 0 + 47TW - 20TW = 27TW&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The world consumed 22,000 TWh in 2017[2]. That means an average power consumption of 2.5TW. If all of that was geothermal, we'd be increasing the cooling rate of the earth's core by about 10%.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[2] &lt;a href=&quot;https://yearbook.enerdata.net/electricity/electricity-domestic-consumption-data.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://yearbook.enerdata.net/electricity/electricity-domestic-consumption-data.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So based on that, how quickly does each TW of geothermal power cool the earth? &#xA;Well, I looked at the most abundant elements of the earth by mass, and found that the weighted average thermal capacitance is about 1000 J/kg/deg C. To get a ballpark idea of the impact 1 TW would make, I'll use that number, and an average internal temperature of 3000 degrees C. To calculate that the thermal energy of the earth, I'll use Q=M&lt;em&gt;c&lt;/em&gt;dT I'll consider a thermal window between 0C and 3000C. The difference in the earth's thermal energy between those points is on the order of 1.8x10^31 J. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In one decade, a 1TW source generates 3.2x10^20 J. In order to have a 1% impact on the average internal temperature of the planet (30 degrees C for our window of analysis), a 1TW source would have to work full time until the sun consumed the earth in 5 billion years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think this is awesome! I wanted to see how awesome though. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What about the fact that humans seem to double their power demand every decade or so? I threw together a quick spreadsheet table and simulated it century by century to see how long it took to get measurable effects on the earth's temperature as our power demands go up through time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It turns out that if we were to convert all our power generation to geothermal today, and double our total global geothermal power generation every decade, we would get 8,400 years of clean energy before cooling the earth's core by 1%!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We would have to make a change soon after though, because if we continued on like that, we'd totally deplete the earth's warmth in centuries. By that time though, we might even have powerful enough technology to reheat the earth artificially.&lt;/p&gt;&#xA;" OwnerUserId="15268" LastActivityDate="2019-02-21T11:55:53.490" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16308" PostTypeId="1" AcceptedAnswerId="16313" CreationDate="2019-02-21T17:06:09.193" Score="10" ViewCount="611" Body="&lt;p&gt;How would steam refract light compared to fog and how would the rainbow appear? Does the temperature of the water drop or ice crystal effect the rainbow in any way? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know the size of the water drop and the shape of ice crystals affects the rainbow. Does the temperature within those 2 forms of water effects light refraction?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could impurities or composition of the raindrop or ice also effect light refraction?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Related: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13831/how-to-tell-if-fog-is-made-out-of-water-droplets-or-ice-crystals&quot;&gt;How to tell if fog is made out of water droplets or ice crystals?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2019-02-21T19:32:34.367" LastActivityDate="2019-02-23T03:46:44.210" Title="Rainbow dynamics?" Tags="|meteorology|temperature|rain|visualization|field-measurements|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16309" PostTypeId="1" CreationDate="2019-02-21T20:50:14.833" Score="2" ViewCount="46" Body="&lt;p&gt;How to interpret bubble voids in pyroclastic density currents? You may see the case on the photo attached. It is; Miocene, densely welded, crystal bearing, LT. Do they have to occur on the top of the current?&lt;a href=&quot;https://i.stack.imgur.com/6VqYH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6VqYH.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="15195" LastEditDate="2019-02-22T08:27:33.473" LastActivityDate="2019-08-28T22:02:35.320" Title="Pyroclastic density currents interpretation" Tags="|pyroclastic-flows|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16312" PostTypeId="2" ParentId="16294" CreationDate="2019-02-22T21:35:00.790" Score="1" Body="&lt;p&gt;It seem that for your application more than mountain height and key saddle you want topographical profiles (like the ones in the figures).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To create such topographical profiles you can download a Digital Elevation Model of the area of interest and analyze it with specialized GIS software like QGis, Global Mapper or ArcGis.&#xA;A recommended global digital elevation dataset is &lt;a href=&quot;https://www2.jpl.nasa.gov/srtm/&quot; rel=&quot;nofollow noreferrer&quot;&gt;SRTM&lt;/a&gt;, but as it doesn't cover the polar areas should be combined with &lt;a href=&quot;https://www.pgc.umn.edu/data/arcticdem/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ArcticDEM&lt;/a&gt;, and &lt;a href=&quot;https://www.pgc.umn.edu/data/rema/&quot; rel=&quot;nofollow noreferrer&quot;&gt;REMA&lt;/a&gt;.  Alternatively &lt;a href=&quot;https://asterweb.jpl.nasa.gov/gdem.asp&quot; rel=&quot;nofollow noreferrer&quot;&gt;ASTER GDEM&lt;/a&gt; is a good one with global coverage or &lt;a href=&quot;https://www.eorc.jaxa.jp/ALOS/en/aw3d30/index.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;ALOS W3D&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you don't want to download data and use specialized software. You might be able to get what you want from a online topographic profiling service like ArcGIS &lt;a href=&quot;http://www.arcgis.com/home/item.html?id=3300cfc33ca74a9fac69d2e0f4ea46e5&quot; rel=&quot;nofollow noreferrer&quot;&gt;Profile geoprocessing service&lt;/a&gt;. This service allows you to draw a line anywhere in the world and get its topographic profile. For example, a profile I just made there of mount Aconcagua looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JAORC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JAORC.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you still want to calculate key saddles, you have to download the Digital Elevation Model and use even more specialized software, like &lt;a href=&quot;https://github.com/edwardearl/winprom&quot; rel=&quot;nofollow noreferrer&quot;&gt;winprom&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-02-22T21:35:00.790" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16313" PostTypeId="2" ParentId="16308" CreationDate="2019-02-22T23:23:40.473" Score="5" Body="&lt;p&gt;&lt;strong&gt;Short answer: the refraction of light is ultimately dependent on both temperature and exact composition of the medium (e.g., liquid water or ice) through which it passes.&lt;/strong&gt; &lt;em&gt;Note: strictly speaking, &quot;steam&quot; typically refers to &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Steam&quot; rel=&quot;nofollow noreferrer&quot;&gt;water vapor at temperatures above the boiling point&lt;/a&gt;, but in casual usage (and for the purposes of this answer) &lt;a href=&quot;https://en.wikipedia.org/wiki/Steam&quot; rel=&quot;nofollow noreferrer&quot;&gt;it is commonly used to describe condensed water droplets occurring in such environments&lt;/a&gt;.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For background, rainbows, and refraction of light in general, occur as light passes between different media (in this case, air and liquid or frozen water) in which the speed of light differs. This property is described by the &lt;a href=&quot;https://www.britannica.com/science/refractive-index&quot; rel=&quot;nofollow noreferrer&quot;&gt;refractive index&lt;/a&gt;, the ratio of the speed of light in a vacuum to its speed passing through a particular medium. A generalized example of refraction as a ray of light passes between media with differing refractive indices is shown here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Tu6jx.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Tu6jx.png&quot; alt=&quot;ray of light being refracted as it passes between two media with differing refractive indices&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Refractive_index&quot; rel=&quot;nofollow noreferrer&quot;&gt;[image source]&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More specifically, however, the amount of refraction depends on both the properties of the medium itself and on the frequency/wavelength of the light itself. For the example of a rainbow, the color pattern is produced by the slight variations in refraction over the range of visible wavelengths for liquid droplets occurring in generally similar environmental conditions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/haOl0.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/haOl0.png&quot; alt=&quot;light at two different wavelengths refracting through a liquid water droplet&quot;&gt;&lt;/a&gt; &lt;a href=&quot;https://plus.maths.org/content/rainbows&quot; rel=&quot;nofollow noreferrer&quot;&gt;[image source]&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Historically, the refractive index has been derived for a large number of media including &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_refractive_indices&quot; rel=&quot;nofollow noreferrer&quot;&gt;air, ice, and both pure liquid water and various liquid water solutions at a variety of temperatures, all with respect to specific wavelengths of light&lt;/a&gt;. &lt;strong&gt;Thus, the differing refractive indices therein show that both the temperature and the composition (including any impurities) of liquid water or ice will indeed affect how light is refracted through them.&lt;/strong&gt; Any more specific details related to the resulting effects would naturally depend on knowing the exact characteristics in question - one particular example, noted below by Keith McClary, is that &lt;a href=&quot;https://www.osa-opn.org/home/gallery/after_images/2010_(1)/10-oct-10_00_00_00/&quot; rel=&quot;nofollow noreferrer&quot;&gt;the larger index of refraction for salt water causes a slightly smaller radius in the resulting rainbow&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Specifically for pure liquid water, while the characteristics of ice crystals and the effects of changing composition are likely too specific to estimate, water's refractive properties may be reasonably estimated over a range of temperatures. For example, &lt;a href=&quot;https://www.spiedigitallibrary.org/conference-proceedings-of-spie/5068/0000/Water-refractive-index-in-dependence-on-temperature-and-wavelength/10.1117/12.518857.full?SSO=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bashkatov and Genina (2002)&lt;/a&gt; present in their Table 1 examples of refractive indices for pure liquid water at temperatures between 0 and 100°C and for a range of wavelengths encompassing the visible light spectrum:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/T8oPX.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/T8oPX.png&quot; alt=&quot;refractive indices for pure liquid water at a range of temperatures for multiple wavelengths of light&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As shown, the differences in refractive index are relatively small even over this range of temperatures, and the relative differences over the visible wavelengths are similar for a given temperature, suggesting that a typical rainbow may well be observed in association with water droplets condensing from steam at high temperatures.&lt;/p&gt;&#xA;" OwnerUserId="14078" LastEditorUserId="14078" LastEditDate="2019-02-23T03:46:44.210" LastActivityDate="2019-02-23T03:46:44.210" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16314" PostTypeId="2" ParentId="6947" CreationDate="2019-02-23T05:42:53.577" Score="4" Body="&lt;p&gt;Today (February 22nd 2019) There are cyclones/typhoons/hurricanes in both the North and South Pacific - Wutip east of Philippines, Oma East of Australia.  They are not twin cyclones as defined above, having formed at different times, and being well over 22 degrees of latitude apart.  Never seen an asymmetrical pair like this before, maybe a function of increasing sea surface temperatures due to global warming.  Link to satellite pictures and text below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.weatherzone.com.au/news/cyclones-update/529321&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.weatherzone.com.au/news/cyclones-update/529321&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15276" LastActivityDate="2019-02-23T05:42:53.577" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16315" PostTypeId="1" AcceptedAnswerId="16321" CreationDate="2019-02-23T08:40:18.457" Score="6" ViewCount="698" Body="&lt;p&gt;In the description of the Norse exploration of America, there are two places mentioned, &quot;Hop&quot; and &quot;Straumfjord&quot;, with some relationship to the same mountains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;E.g. &lt;a href=&quot;https://archive.org/details/winelandthegood00reevrich&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;The finding of Wineland the Good&lt;/em&gt;&lt;/a&gt;, p. 50:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;They concluded that the mountains of Hop, and those which they had now&#xA;  found, formed one chain, and this appeared to be so because they were&#xA;  about an equal distance removed from Streamfirth, in either direction.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;According to the interpretation by &lt;a href=&quot;https://en.wikipedia.org/wiki/K%C3%A5re_Prytz&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kåre Prytz&lt;/a&gt; these places are Boston, Massachusetts (Straumfjord) and Rhode Island (Hop), and the meaning of the text is that (1) the three locations (Boston, R.I., the mountains) form an equilateral triangle, and (2) the mountains are visible from both Boston and R.I.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Casual inspection of a map suggests this might well be accurate, but I am wondering if the exact peaks can be pinned down more specificly?&lt;/p&gt;&#xA;" OwnerUserId="15277" LastEditorUserId="11908" LastEditDate="2019-03-04T00:38:09.723" LastActivityDate="2019-03-04T00:38:09.723" Title="Which mountains (or hills) are visible from both Boston and Rhode Island?" Tags="|geography|mountains|gis|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16316" PostTypeId="1" CreationDate="2019-02-23T11:24:48.383" Score="4" ViewCount="43" Body="&lt;p&gt;For molecular-sized particles to disperse around the entire planet, would they have to reach the stratosphere, or could air currents in the troposphere distribute them? Are particles dispersed somewhat equally or are they laid down according to what air current they are swept into?&lt;/p&gt;&#xA;" OwnerUserId="15267" LastActivityDate="2019-02-23T11:24:48.383" Title="For fine particles to get dispersed throughout the globe via atmospheric circulation, in what level of the atmosphere would they have to travel?" Tags="|atmospheric-circulation|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16319" PostTypeId="1" AcceptedAnswerId="16320" CreationDate="2019-02-24T00:42:45.900" Score="3" ViewCount="112" Body="&lt;p&gt;According to &lt;a href=&quot;https://space.stackexchange.com/a/34307/12102&quot;&gt;this answer&lt;/a&gt; the weather at the InSight lander on Mars can now be seen online at &lt;a href=&quot;https://mars.nasa.gov/insight/weather/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://mars.nasa.gov/insight/weather/&lt;/a&gt; This includes the wind speed and I believe the direction (if that's what those little flags mean).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; But I'm not sure so I'd like to ask; what do the little flags on these martian wind speed data points mean?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fHZw5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fHZw5.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;A bit of history...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the question &lt;a href=&quot;https://space.stackexchange.com/q/21680/12102&quot;&gt;Was the telltale on the Mars Phoenix Lander used for meteorology? Why not a hot wire anemometer instead?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FJbPa.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FJbPa.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; GIF from images transmitted from Mars. From the &lt;a href=&quot;http://marslab.au.dk/research/instrument-development/the-telltale-project/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Telltale project&lt;/a&gt; page on the &lt;a href=&quot;http://marslab.au.dk/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mars Simulation Laboratory&lt;/a&gt;. Also &lt;a href=&quot;https://web.archive.org/web/20120220080017/http://www.marslab.dk/TelltaleProject.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;archived here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T20:52:05.860" LastActivityDate="2019-08-28T20:52:05.860" Title="What do the little flags on these martian wind speed data points mean?" Tags="|meteorology|mars|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16320" PostTypeId="2" ParentId="16319" CreationDate="2019-02-24T00:52:11.150" Score="5" Body="&lt;p&gt;They indicate wind direction (given by the long line or &quot;barb&quot;) and speed (given by the shorter flags extending from each barb). In the same linked page you can read:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The barbs extending from each wind speed data point indicate the&#xA;  compass direction of the wind (e.g., a wind blowing from the north&#xA;  will have a barb straight up above the point; a wind blowing from the&#xA;  west will have a barb off to the left). Full and half flags extending&#xA;  from the barbs indicate the wind speed, with each half flag&#xA;  representing approximately 2.5 meters per second. A circle in place of&#xA;  a barb indicates a wind speed less than 2.5 meters per second.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-02-24T00:52:11.150" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16321" PostTypeId="2" ParentId="16315" CreationDate="2019-02-24T01:36:27.037" Score="6" Body="&lt;p&gt;As Boston and Rhode Island are whole areas more than points, the question is easier to answer the other way around: From which mountain you can see Boston and Rhode Island?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer the question I'll use the &lt;a href=&quot;https://www2.jpl.nasa.gov/srtm/&quot; rel=&quot;noreferrer&quot;&gt;SRTM Digital Elevation Model&lt;/a&gt; at 30 meters resolution, and pick the following five mountains or hills that seem good candidates:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sRAuQ.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sRAuQ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shown elevations are the ones derived from STRM data. From each of these points I've made a view shed analysis. And for easier comparison I've put them together in the following animation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JAE9H.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JAE9H.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In these view shed analysis, the areas in read represent the one that would be visible from the corresponding mountain or hill. As you can see, &lt;strong&gt;Blue Hill and Moose hill are visible from some parts of Boston and Rhode Island. So that chain of hills (including Tower Hill) is definitely visible from many parts of both areas.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the mountains further inland as Wachusett Mt. and Monadnock Mt., they don't seem to be visible from the coastal areas of Rhode Island.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-02-24T01:36:27.037" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="16322" PostTypeId="1" CreationDate="2019-02-24T14:09:41.780" Score="4" ViewCount="37" Body="&lt;p&gt;The discovery of hearths and other carbon dated items on an island off the north east coast of Canada puts modern humans there 2,000 years before the Alaskan land bridge existed.  The glaciers of North America would have prevented the west to east traverse at this time.  They had obsidian tools.  Where did they get it?  Where were they from?&lt;/p&gt;&#xA;" OwnerUserId="15286" LastEditorUserId="2470" LastEditDate="2019-02-24T16:08:15.160" LastActivityDate="2019-02-24T16:08:15.160" Title="Where did the heiltsuk's find obsidian?" Tags="|earth-history|archaeology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16323" PostTypeId="1" CreationDate="2019-02-24T14:57:59.440" Score="4" ViewCount="182" Body="&lt;p&gt;Water vapor looses it energy at night (no sun, no UV) and this is deposited as dew.  Change of state requires a massive energy change, in general.  Is the greenhouse effect of CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; not lost when it gets dark and there is no UV entering the Earth? If not how is the energy stored in the atmosphere by CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;? None of the research I can find, even from the 1950's or 1960's, has addressed this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am a doubter, but I do see that CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; has the ability to warm. Just can't see how this is maintained overnight since there are about 12 hours of darkness daily.  This seems to be the case with water vapor loosing energy daily or it would be 150 degrees (or more) in the South (USA) by July. I am a chemist with a strong thermodynamics background. Thanks.&lt;/p&gt;&#xA;" OwnerUserId="15287" LastEditorUserId="11908" LastEditDate="2019-02-24T18:11:51.420" LastActivityDate="2019-02-25T01:41:28.273" Title="How CO$_2$ warming effect stays overnight?" Tags="|climate-change|greenhouse-gases|energy-balance|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16324" PostTypeId="2" ParentId="4346" CreationDate="2019-02-24T16:27:36.553" Score="1" Body="&lt;p&gt;Yes today’s photosynthesis is occurring but so is the oxidation of the carbon based plant material when they decay and consumed. &#xA;In order to have a surplus molecular Oxygen quantity the products of photosynthesis cannot undergo oxidation. &#xA;Our biggest threat is the diminishing of molecular Oxygen because that is what absorbs UV energy and releases it as light before the UV can reach the Earth’s surface and become light and heat where it can cause the most damage with retainment of destructive forces at the earths surface. &#xA;Remember that petroleum and coal are the products of photosynthesis and we are consuming them at an exponential rate. &lt;/p&gt;&#xA;" OwnerUserId="15288" LastActivityDate="2019-02-24T16:27:36.553" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16325" PostTypeId="2" ParentId="16323" CreationDate="2019-02-24T18:09:14.967" Score="13" Body="&lt;p&gt;CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; doesn't significantly interact with solar radiation or UV, and doesn't store any significant amount of heat. What CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; effectively does is scattering infrared radiation emitted by the Earth, and such radiation is emitted day and night. Let me explain this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All objects emit a type of radiation called &lt;a href=&quot;https://en.wikipedia.org/wiki/Black_body&quot; rel=&quot;noreferrer&quot;&gt;black body radiation&lt;/a&gt;. And the color (wavelength) and power of that radiation depends on temperature.&#xA;This radiation becomes evident to the eyes only at temperatures above 500 °C, when stuff start to glow, as amber, the heating element of a stove, the filament of a incandescent light bulb, or the Sun itself. However, this radiation is emitted also by colder objects, as the human body, the ocean and even glaciers and ice cubes. But we can't see that radiation because is very faint and mostly composed of infrared radiation that is invisible to the eye.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However it can be detected with cameras, and that's why military and surveillance thermal infrared cameras are capable to see in the night, because they see the radiation the human body emits. Here an example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8AR5t.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8AR5t.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[picture from &lt;a href=&quot;https://www.videoblocks.com/video/scientific-thermal-infrared-heat-mapping-image-of-urban-environment-sgds2yrbgivpcwreo&quot; rel=&quot;noreferrer&quot;&gt;Videoblocks&lt;/a&gt;]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The interesting fact to keep in mind, is that for Earth to be in thermal equilibrium (meaning that the mean temperature is stable or changing very slowly), &lt;strong&gt;the amount of infrared radiation that Earth's emits have to be equal to the amount of radiation it receives from the Sun&lt;/strong&gt;, so it is a lot!.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;The effect of CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Now, the effect of CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; is not to store any energy, it just blindly absorb and re-emit infrared radiation (foot note 1), there is no significant storage. The key point is that most of the infrared radiation it absorbs comes from the surface, and then it re-emits it in a random direction. As consequence of this, half of the radiation that was escaping to space is sent back to the surface, and that's the origin of the warming effect of CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the effect of CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; is similar to that of a survival blanket like this one:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GXUvV.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GXUvV.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[image from &lt;a href=&quot;https://www.aliexpress.com/item/Portable-survival-blanket-Outdoor-Waterproof-Emergency-Blanket-Rescue-Blankets-Thermal-Mylar-Emergency-Blankets-Camping-Blankets/32731399908.html&quot; rel=&quot;noreferrer&quot;&gt;Aliexpress]&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This blankets don't produce or store heat, it is not good insulators either. This blanket just reflect back some of the infrared radiation that is leaving the body, effectively keeping it warmer. That's the same effect of greenhouse gases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's imagine an atmosphere with no greenhouse gases. The radiation balance would look like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zKEeL.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zKEeL.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this case the equilibrium temperature of Earth would be that on which the outgoing energy is equal to the incoming energy. That equilibrium would happen when the Earth's surface is at -18 °C, because at that temperature (according to &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law&quot; rel=&quot;noreferrer&quot;&gt;Stefan-Boltzmann law&lt;/a&gt; that say that emitted energy &lt;span class=&quot;math-container&quot;&gt;$=\sigma T^4$&lt;/span&gt;), in average,  the black body radiation of Earth's (working day and night) would be powerful enough to equal the amount of energy we receive from the Sun during the day. So in this scenario Earth's mean temperature would be a freezing -18°C (like in the Moon).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But thankfully we have greenhouse gases, and the actual radiation balance of Earth looks more like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6EggL.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6EggL.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here, half of the energy radiated by the surface is sent back to the surface by greenhouse gases (as a survival blanket does). This effect (greenhouse effect) warms up the surface. And it will warm the surface up until it emits enough energy such that the half of it that can actually escape to space is enough to equal the incoming radiation and reestablish the balance. Does that make sense?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this simplified scenario that balance would happen at a nice and warm 30°C. Now, if we have too much geenhouse gases, this heating effect will overshoot and we will be too hot. That's what have people worried about: we are putting too many &quot;blankets&quot; on Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Foot notes&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1.- As a Chemist you might be interested that this infrared absorption capacity is related to the asymmetry of the CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; molecule and it's associated vibrational modes).&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-25T01:41:28.273" LastActivityDate="2019-02-25T01:41:28.273" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16326" PostTypeId="2" ParentId="16323" CreationDate="2019-02-24T20:18:39.273" Score="2" Body="&lt;p&gt;The greenhouse effect is a process that occurs when gases in Earth's atmosphere trap the Sun's heat. This process makes Earth much warmer than it would be without an atmosphere. The greenhouse effect is one of the things that makes Earth a comfortable place to live. &lt;a href=&quot;https://www.youtube.com/watch?v=sTvqIijqvTg&quot; rel=&quot;nofollow noreferrer&quot;&gt;This video explains it very well&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=sTvqIijqvTg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HpOgl.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15291" LastEditorUserId="11908" LastEditDate="2019-02-24T20:21:12.010" LastActivityDate="2019-02-24T20:21:12.010" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16327" PostTypeId="1" AcceptedAnswerId="16336" CreationDate="2019-02-25T11:02:55.290" Score="5" ViewCount="1312" Body="&lt;p&gt;Many online sources stresses how much the antarctic wind is dangerous for the structures and for the personnel, yet most buildings I see are built off the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suppose that is due to the different thermal conductivity of the air vs the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yet, many arctic dwelling tribes build enclosed hut on contact with the ground, as if the wind chill is actually much more dangerous than the heat lost with the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Besides, building underground should guarantee an average temperature and/or depending on depth a better temperature for materials and people.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Habitats should still need insulation, but maybe they would reduce the fuel consumption to heat the habitats.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could you point me towards research papers and/or data regarding antarctic soil temperature?&lt;/p&gt;&#xA;" OwnerUserId="15295" LastEditorUserId="11908" LastEditDate="2019-03-11T21:30:49.037" LastActivityDate="2019-03-11T21:30:49.037" Title="Why antarctic research stations are built above ground instead of on the ground or underground?" Tags="|glaciology|antarctic|" AnswerCount="2" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="16328" PostTypeId="1" CreationDate="2019-02-25T14:48:42.153" Score="5" ViewCount="438" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8TTSq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8TTSq.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/kR1OD.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kR1OD.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/DWOIK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DWOIK.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are images of a stone found and used extensively in the Jammu &amp;amp; Kashmir region between India and Pakistan. These are called devir or devri in the local parlance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Following is the description of the stone according to one website that I looked up:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Devri stone is an impure lime stone extracted from earth at various parts of the Kashmir. The stone is soft in its nature and gives white appearance after carving. The stone can be molded to any form or shape.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I am planning to write a research paper on 'hamam' which is an underfloor heating system used in the kashmir valley, devri stones are commonly used as the floor surface for the hamams. I would like to know if there is an globally accepted name for this type of stone, so that I can report that in my paper. Also, it would make easy for me to acquire scientific data about these stones. &lt;/p&gt;&#xA;" OwnerUserId="15296" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T08:58:26.350" LastActivityDate="2019-08-28T08:58:26.350" Title="Identification of limestone type" Tags="|geology|rocks|petrology|limestone|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16331" PostTypeId="2" ParentId="16327" CreationDate="2019-02-25T17:58:10.517" Score="2" Body="&lt;p&gt;I suspect the reason has to do with the stability of the ground due to issues with permafrost.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In areas with permafrost if you build right on or in the ground then waste heat from the building will start to melt the permafrost.  Once the permafrost starts to melt it cannot effectively support the weight of the building and the building starts to settle further into the ground.  Unfortunately the settling differs over the support of the building leading to cracking and deformation of the building.  To build on the ground in a climate with permafrost requires a lot of engineering and additional construction steps to make a stable platform for the building while preventing the supporting permafrost hardened ground from melting due to waste heat from the building itself.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Canada's north many buildings are built by pile driving metal piping into the ground past the permafrost layer.  These pipes are then cut above the ground to provide a level building surface.  This construction allows some insulation below the flooring to allow the soil underneath to remain frozen and solid enough to support the weight of the building.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Traditional arctic dwelling peoples did not heat their living quarters to the same extent as most people do now, additionally if their homes settled do to melting it wasn't as big an issue as it is with current building strategies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following site is about the issues of dealing with frozen ground.  &lt;a href=&quot;https://nsidc.org/cryosphere/frozenground/people.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://nsidc.org/cryosphere/frozenground/people.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2019-02-25T17:58:10.517" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16333" PostTypeId="1" CreationDate="2019-02-26T01:55:08.160" Score="1" ViewCount="642" Body="&lt;p&gt;For example, if there were a large land area with exposed basalt, in the middle of which is a smaller isolated patch of Granite, what is that isolated patch called?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I came across the single-word geological term for this some months ago, and now it eludes me. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Something tells me it had a similar ring to Moraine (as in glacial debris), but I may well be misremembering that connection.&lt;/p&gt;&#xA;" OwnerUserId="10781" LastActivityDate="2019-02-26T03:53:27.260" Title="What is an isolated land area of one type of rock surrounded by land of a differing rock type called?" Tags="|geology|geography|terminology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16335" PostTypeId="1" CreationDate="2019-02-26T03:03:23.103" Score="1" ViewCount="411" Body="&lt;p&gt;252 million years ago, Siberia was subject to a mass series of flood basalt eruptions, creating a large igneous province called the Siberian Traps.  Today, it measures three million square miles (7.77 km&lt;sup&gt;2&lt;/sup&gt;) in area and a volume of one million cubic miles (4.17 km&lt;sup&gt;3&lt;/sup&gt;).  But that is the province's &lt;em&gt;current&lt;/em&gt; size, which means that it has been measured with 252 million years of erosion into account.&lt;/p&gt;&#xA;&lt;p&gt;So the question is—&lt;strong&gt;Do we have any idea how big the Siberian Traps were initially?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="4985" LastEditorUserId="20" LastEditDate="2022-01-26T09:10:36.577" LastActivityDate="2022-01-26T09:10:36.577" Title="How big were the Siberian Traps originally?" Tags="|geology|volcanology|structural-geology|regional-geology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16336" PostTypeId="2" ParentId="16327" CreationDate="2019-02-26T03:35:56.090" Score="6" Body="&lt;p&gt;Antarctica is a whole continent and it is as diverse as any other continent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two reasons buildings are often built off the ground on pillars.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1.- Avoid snow accumulation: Although in average Antarctica is a dry continent, in some coastal areas there can be massive amounts of snow accumulation. Building on pillars spare the buildings to get buried and most importantly allows the wind to blow the snow away. If you build on the surface, the snow will accumulate on the lee of the building. This happens even if there is very small snow fall, because wind transport the snow for long distance and the lee of a building is favourable for accumulation. Therefore, even it snows 1 mm, the millimiter that fell in all the ground 100 km upwind can end up piled behind your hut, and block your door.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2.- To rise buildings: Many of the bases are built on ice, and all those are buit on the accumulation area of glaciers or ice sheets. Therefore, with time the surface will rise relative to the building and will eventually swallow it. Therefore, in many cases (like the Amudsen-Scott base at the South Pole). The pillars are designed to be extended, therefore allowing to rise the building as the ice below thickens, keeping it at an optimal distance for the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding the inquiry about soil temperature, again that is too broad. Imaging asking about the soil temperature in North America, the answer would be quite different for Mexico than for Alaska. The same contrast can be found between bare ground areas of the Antarctic Peninsula at latitude 60°S and at almost 5,000 m of elevation on Mount Vinson plateau at latitude ~80°S&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-26T05:09:16.147" LastActivityDate="2019-02-26T05:09:16.147" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16337" PostTypeId="2" ParentId="16333" CreationDate="2019-02-26T03:53:27.260" Score="2" Body="&lt;p&gt;You might want to look at these topics, depends on the size of features that you want to look at:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Batholith -- s a large mass of intrusive igneous rock (also called plutonic rock), larger than 100 square kilometres (40 sq mi) in area,[1] that forms from cooled magma deep in the Earth's crust. Batholiths are almost always made mostly of felsic or intermediate rock types, such as granite, quartz monzonite, or diorite -- &lt;a href=&quot;https://en.wikipedia.org/wiki/Batholith&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Batholith&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Stock (geology) ==  is an igneous intrusion that has a surface exposure of less than 100 square kilometres (40 sq mi),[differing from batholiths only in being smaller. A stock has a discordant relationship with the rocks that it intrudes. The term stock usually refers to individual, relatively small plutons, less than 20 km (12 mi) diameter, usually in relative isolation.Many stocks are cupolas of hidden batholiths. Circular or elliptical stocks may have been vents feeding former volcanoes -- &lt;a href=&quot;https://en.wikipedia.org/wiki/Stock_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Stock_(geology)&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Dike (geology) --  is a sheet of rock that is formed in a fracture in a pre-existing rock body. Dikes can be either magmatic or sedimentary in origin. Magmatic dikes form when magma flows into a crack then solidifies as a sheet intrusion, either cutting across layers of rock or through a contiguous mass of rock. Clastic dikes are formed when sediment fills a pre-existing cracks -- &lt;a href=&quot;https://en.wikipedia.org/wiki/Dike_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Dike_(geology)&lt;/a&gt; &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="15253" LastActivityDate="2019-02-26T03:53:27.260" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16340" PostTypeId="1" AcceptedAnswerId="16342" CreationDate="2019-02-26T18:14:03.243" Score="3" ViewCount="160" Body="&lt;p&gt;I'm a potter.  I find what I think are iron concretions in a deep red local clay.  I fired these iron concretions to cone 6 (about 2100F) and when I removed it from the kiln (room temp) they were then magnetic.  I tested for magnetism before and after firing just because I was curious.  What would cause this behavior?   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for the help. &lt;/p&gt;&#xA;" OwnerUserId="15310" LastActivityDate="2019-02-26T21:58:00.680" Title="Heating and cooling a non-magnetic iron ore causes it to become magnetic?" Tags="|magmatism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16341" PostTypeId="2" ParentId="13831" CreationDate="2019-02-26T19:06:14.050" Score="4" Body="&lt;p&gt;This doesn't aim to be a complete answer, but after putting a juicy bounty at Aviation SE on the question &quot;&lt;a href=&quot;https://aviation.stackexchange.com/q/60213/34312&quot;&gt;Can pilots tell if a cloud or fog is made out of water droplets or ice crystals when flying through it?&lt;/a&gt;&quot;, the answer seem to be: &lt;strong&gt;No, they can't&lt;/strong&gt;. And all the things to look at to detect ice clouds doesn't seem to be useful if you don't have a plane at hand. There is nothing like &quot;there is a special refraction pattern around the lights on the wings&quot;, or such.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far it seem like ice and water clouds are indistinguishable.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-02-27T23:01:30.947" LastActivityDate="2019-02-27T23:01:30.947" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16342" PostTypeId="2" ParentId="16340" CreationDate="2019-02-26T21:58:00.680" Score="2" Body="&lt;p&gt;What's happening is called induced magnetism, detailed in a variety of places, including &lt;a href=&quot;https://academic.oup.com/gji/article/195/3/1534/622882&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper by Kostadinova-Avramova and Kovacheva in Geophysical Journal International&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It is well established that baked clays, when cooling from&#xA;  temperatures around 700 °C in a weak magnetic field, such as that of&#xA;  the Earth, acquire a thermoremanent magnetization (TRM) that is&#xA;  related to the direction and intensity of that field.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;When materials are heated above their &lt;a href=&quot;https://en.wikipedia.org/wiki/Curie_temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;Curie temperature&lt;/a&gt; -- which varies based on the material -- they lose any permanent magnetic properties they had. As the material cools below its Curie temperature, its magnetic particles are influenced by the local magnetic field and the material develops a new, parallel magnetic structure in response.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So your ferrous clay could be picking up a magnetic field from the Earth, from a local electromagnetic field generated by your kiln or other electrical sources, or even a sufficiently strong local magnetic source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This mechanism is sufficiently well understood that the field of paleomagnetism studies ancient fired clay objects and other materials of known dates to determine the strength of Earth's magnetic field in a given era and region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.israel21c.org/history-of-earths-magnetic-field-exposed-in-judean-pottery/&quot; rel=&quot;nofollow noreferrer&quot;&gt;History of Earth’s magnetic field exposed in Judean pottery&lt;/a&gt; explores one such application of the process:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In a new study published in Proceedings of the National Academy of&#xA;  Sciences (PNAS), researchers from Tel Aviv University, Hebrew&#xA;  University of Jerusalem and University of California-San Diego cite&#xA;  data obtained from the analysis of 67 well-dated Judean jar handles.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;These heat-impacted ceramic pots, which bear royal stamp impressions&#xA;  from the eighth to second centuries BCE, show evidence of changes in&#xA;  the strength of the geomagnetic field over the years.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;“The period spanned by the jars allowed us to procure data on the&#xA;  Earth’s magnetic field during that time — the Iron Age through the&#xA;  Hellenistic Period in Judea,” said Erez Ben-Yosef of TAU’s Institute&#xA;  of Archaeology, the study’s lead investigator.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2019-02-26T21:58:00.680" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16343" PostTypeId="2" ParentId="16328" CreationDate="2019-02-26T23:11:26.177" Score="4" Body="&lt;p&gt;Limestones are usually categorized following the &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Dunham_classification&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dunham &amp;amp; Folk classification&lt;/a&gt;. Only very rare or special limestones were given a name and these are often named after the location where they can be found e.g. &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Travertine&quot; rel=&quot;nofollow noreferrer&quot;&gt;Travertine&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The images you provided are not very explicit which makes it literally impossible to clearly identify the limestone. Please consider next time to upload close up pictures that show the composition e.g. bioclasts and cements of the limestone. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, there is a &lt;a href=&quot;http://www.geosocindia.org/index.php/jgsi/article/download/64163/50131&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt; by the Geological Society of India were the authors date a limestone from the Jammu region which they refer to as &lt;strong&gt;Jammu limestone&lt;/strong&gt; or &lt;strong&gt;Great limestone&lt;/strong&gt;. The authors suggest that the limestones are from the Precambrian due to &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Stromatolite&quot; rel=&quot;nofollow noreferrer&quot;&gt;stromatolites&lt;/a&gt; that were found there in. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope this helps!&lt;/p&gt;&#xA;" OwnerUserId="13604" LastEditorUserId="725" LastEditDate="2019-02-28T03:37:22.780" LastActivityDate="2019-02-28T03:37:22.780" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16346" PostTypeId="2" ParentId="16266" CreationDate="2019-02-27T05:51:11.807" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://www.sciencenews.org/article/dino-dooming-asteroid-impact-created-chilling-sulfur-cloud&quot; rel=&quot;nofollow noreferrer&quot;&gt;Estimated sulfur release&lt;/a&gt; 325 gigatonnes = 325,000 teragrams. The numbers in this diagram are in teragrams&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://slideplayer.com/slide/6871296/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sulfur Cycle&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/1CxoL.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1CxoL.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;so the release is &lt;span class=&quot;math-container&quot;&gt;$\approx 1000\times $&lt;/span&gt; today's annual sulfur cycle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think most of the sulfur compounds would be washed into the ocean and then deposited into sediments. I can't find how much sulfur is currently in the oceans, &lt;a href=&quot;https://infinitespider.com/ocean-smell-like/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; says gigatons (because you can smell it). I also can't find how fast the increased sulfur would be deposited.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another issue is that, unlike iridium, there is normally a lot of sulfur in marine deposits, so it is hard to distinguish what comes from Chicxulub.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-02-27T05:51:11.807" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16348" PostTypeId="1" CreationDate="2019-02-27T07:59:19.980" Score="3" ViewCount="114" Body="&lt;p&gt;What other sources of volcanic gas emissions can there be on earth?&lt;/p&gt;&#xA;" OwnerUserId="15313" LastEditorUserId="595" LastEditDate="2019-02-27T08:25:02.713" LastActivityDate="2019-02-28T03:31:09.360" Title="Can volcanic gases be emitted in any other way besides volcanic eruptions" Tags="|volcanology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16349" PostTypeId="1" CreationDate="2019-02-27T09:20:38.073" Score="1" ViewCount="63" Body="&lt;p&gt;After answering this question: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/7627/how-did-plants-adapt-to-small-sfco-2-levels-past-400k-years-why-wont-they/15852#15852&quot;&gt;How did plants adapt to &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; levels past 400k years? Why won't they do it again?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know Permo-Triassic mass extinction is associated to a catastrophic event, but I wonder if, in terms of neocatastrophism, other factors, concretly &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; low levels shown in this graph, were a prelude to Permo-Triassic mass extinction, affecting the basis of ecological chain at landmasses and oceans.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JGK1d.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JGK1d.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Phanerozoic_Carbon_Dioxide.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;. From Gradstein et al.,2005&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.researchgate.net/profile/James_Ogg/publication/46658757_A_New_Geologic_Time_Scale_with_special_reference_to_Precambrian_and_Neogene/links/0f3175381b7a7b97fe000000/A-New-Geologic-Time-Scale-with-special-reference-to-Precambrian-and-Neogene.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Gradstein, FM, JG Ogg and AG Smith&lt;/strong&gt; (2005) &lt;em&gt;&quot;A geologic time scale 2004&quot;&lt;/em&gt;, &lt;strong&gt;Cambridge University Press&lt;/strong&gt; ISBN 0521786738&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-02-27T09:57:18.073" LastActivityDate="2019-02-27T09:57:18.073" Title="Did low $\small\sf{CO_2}$ levels affected Permo-Triassic mass extinction?" Tags="|geology|paleontology|mass-extinction|extreme-weather|paleobotany|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16351" PostTypeId="2" ParentId="16348" CreationDate="2019-02-27T13:27:03.283" Score="7" Body="&lt;p&gt;Volcanic gases are emitted by a number of ways besides eruptions:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Dissolved gases in heated groundwater.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using a geothermal complex like Yellowstone National Park along Wyoming-Montana border in USA, volcanic gases are emitted through groundwater and water vapor from heated geothermal springs.  One of the most impressive aspects of Yellowstone is that steam rises from everywhere: in parking lot storm drains, potholes, not just from the geysers or springs.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Gas venting from volcanic crater when the volcano is not active.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gases will vent from volcanic craters between eruption cycles. The emitted gases can be used to determine the level of activity beneath the surface by monitoring volume and chemical composition. Changes in volume and composition can indicate a change in activity up or down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Often the gases emissions are not visibly noticeable.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Gases can be emitted from a underlying magma chamber through cracks and fissures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mount Nyiragongo in Congo has localized carbon dioxide toxicity, known locally as 'mazuku' which are where the gas seeps from the ground in relatively high levels, without the dispersing effects of wind.  This can occur miles from the volcano's summit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Great African Rift complex has numerous lakes where CO&lt;sub&gt;2&lt;/sub&gt; build is a serious concern.&#xA;Strongly stratified lakes can trap large amounts of CO&lt;sub&gt;2&lt;/sub&gt; deep within the lake.&#xA;This is evidence that volcanic gases can be emitted across a wide area over a volcanic complex not limited to surface boundaries of a volcano.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="1149" LastEditorUserId="725" LastEditDate="2019-02-28T03:31:09.360" LastActivityDate="2019-02-28T03:31:09.360" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16352" PostTypeId="1" AcceptedAnswerId="25190" CreationDate="2019-02-27T20:28:56.087" Score="5" ViewCount="60" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Airglow&quot; rel=&quot;noreferrer&quot;&gt;Airglow&lt;/a&gt; is caused, among other factors, by recombination of atoms ionized during the day. This makes me think that during the night concentration of these ions should reduce, lowering intensity of airglow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But is this reduction of intensity actually measurable, or is the recombination so slow as to preserve airglow at almost the same intensity?&lt;/p&gt;&#xA;" OwnerUserId="12360" LastActivityDate="2023-05-14T09:59:05.993" Title="Does airglow intensity systematically change during the night?" Tags="|atmosphere|upper-atmosphere|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16354" PostTypeId="2" ParentId="13988" CreationDate="2019-02-28T04:10:19.297" Score="3" Body="&lt;p&gt;A Korean here.&#xA;Haean Myeon in Gangwon-do has two theories of creation. One is Meteor impact and another is differential erosion. There were no meteor related evidence found at Haean so the erosion theory is more agreed upon at the moment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Direct translation from introduction website for Hae An:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;According to the analysis of the granite of the punchbowl basin [nickname for Haean], it consists of 71% feldspar, 22% quartz and 5.7% mica. Feldspar is much more weathering than quartz and mica, and since it is rapidly clayed at room temperature, the lowland is eroded earlier than the current highland with high resistance to weathering, resulting in this unusual branching form.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="15318" LastEditorUserId="106" LastEditDate="2019-02-28T08:21:42.693" LastActivityDate="2019-02-28T08:21:42.693" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16356" PostTypeId="1" CreationDate="2019-02-28T05:33:03.017" Score="9" ViewCount="731" Body="&lt;p&gt;Let me be straight up. I'm a physicist, I've no doubt about climate change and the part we play in it.  I had been reading about cattle being one of the alleged main causes of climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I get that they make methane, and we have a LOT of them, So I ran some numbers:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Roughly 93 million cattle in the United states in 2017 (some sources claim lower, but I'm going with the higher one). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Prior to humans killing the Buffalo off, there were approximately 50-100 million of them across the united states.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A quick Wiki search, estimates that buffalo (bison) produce significantly more methane than domestic cattle (though I don't know for sure that this is true).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These numbers seem to match up pretty well insofar as they're greenhouse gas contributions, so now I'm wondering if the argument is viable?  I know there were other herds around the world too, so I just found myself rather curious. Has anyone run the numbers thoroughly?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the flip side, I could see the sheer number of humans being an issue, I'll try and run that later.&lt;/p&gt;&#xA;" OwnerUserId="15320" LastEditorUserId="2470" LastEditDate="2021-05-02T05:05:00.607" LastActivityDate="2024-03-11T18:53:01.533" Title="Are cattle really contributing to global warming?" Tags="|climate-change|greenhouse-gases|" AnswerCount="2" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="16357" PostTypeId="2" ParentId="16356" CreationDate="2019-02-28T08:13:53.510" Score="3" Body="&lt;p&gt;There have been a few papers published on that topic. &lt;a href=&quot;https://academic.oup.com/jas/article-abstract/73/8/2483/4632901&quot; rel=&quot;nofollow noreferrer&quot;&gt;Johnsons &amp;amp; Johnson, 1995&lt;/a&gt; for example estimate the amount of methane produced in a ruminant livestock to be 250 - 500 L/day. They conclude that cattle will contribute to little less than 2% of the global warming that we might face in 50 - 100 years time.&lt;/p&gt;&#xA;&lt;p&gt;In contrast in a paper by &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0301421510000066&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oliver et al., 2010&lt;/a&gt; the authors looked at the per person CO&lt;sub&gt;2&lt;/sub&gt; emission of cruise ships traveling from and to New Zealand. The found that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Emissions factors for individual journeys by cruise ships to or from&#xA;New Zealand in 2007 ranged between 250 and 2200 g of CO&lt;sub&gt;2&lt;/sub&gt; per&#xA;passenger-kilometre (g CO&lt;sub&gt;2&lt;/sub&gt; per p-km), with a weighted mean of 390 g&#xA;CO&lt;sub&gt;2&lt;/sub&gt; per p-km. The weighted mean energy use per passenger night for the&#xA;“hotel” function of these cruise vessels was estimated as 1600 MJ per&#xA;visitor night, 12 times larger than the value for a land-based hotel.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;As you can see cruise ships are probably far more of a „global warming machine“ than cattle - but serve only very few people. I personally think (and I might be wrong with this) that methane production in cattle can and is easily used by political groups to fight against the conditions in which the cattle are held and against the massive consumption of meat.&lt;/p&gt;&#xA;" OwnerUserId="13604" LastEditorUserId="2470" LastEditDate="2021-05-02T05:09:10.457" LastActivityDate="2021-05-02T05:09:10.457" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16360" PostTypeId="2" ParentId="16356" CreationDate="2019-02-28T17:31:03.170" Score="9" Body="&lt;p&gt;Let's just talk about cattle here and ignore other factors related to cattle production for now.&lt;/p&gt;&#xA;&lt;p&gt;The current cattle number (93 million) you found is probably the total number of dairy cow and beef cattle. In your argument, it is possible that bison has much more emission than cattle on pasture. But the emission from cattle in feedlot and dairy farm is much larger than the cattle on pasture because of their diet chosen by us (human).&lt;/p&gt;&#xA;&lt;p&gt;Typical beef cattle (steers and heifers) in the U.S. spend one year on pasture, and 5-6 month in feedlot before slaughter (unlike Argentina beef cattle which are fully raised on pasture). In feedlot, these young cattle (yearlings) are intensively fed with high protein feed in order to get them fatten up in a very short time. The U.S. dairy cows spent most of their time on dairy farm (unlike the Swiss cows who are raised on pasture). They live for about 5 years and are continuously fed with high protein forage to ensure their milk production. Both beef cattle and dairy cows have a high protein diet that result in high emission of methane (the impact of methane is 25 times worse than CO&lt;sub&gt;2&lt;/sub&gt; in terms of warming).&lt;/p&gt;&#xA;&lt;p&gt;The closest comparable cattle to bison is beef cow which spend most of its life time (about 10 years) on pasture and are only occasionally fed with low quality hay when there is a shortage on pasture. But again, the life span of a beef cow may be different from the buffalo and beef cows may eat more because they are basically pregnant very year(!).&lt;/p&gt;&#xA;&lt;p&gt;California has this new policy that tries to cope with dairy cow methane emission from their manure. If you are interested, there is a recent study done by University of California Agricultural Issue Center here (&lt;a href=&quot;https://aic.ucdavis.edu/wp-content/uploads/2019/01/DairyManure-1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://aic.ucdavis.edu/wp-content/uploads/2019/01/DairyManure-1.pdf&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="15327" LastEditorUserId="2470" LastEditDate="2021-05-02T05:07:32.540" LastActivityDate="2021-05-02T05:07:32.540" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16361" PostTypeId="2" ParentId="16294" CreationDate="2019-02-28T23:17:43.633" Score="2" Body="&lt;p&gt;After investigating a number of the options and data outlined I thought the STRM was the best bet.  I was unable to find a place where I could download the data in a file that I could read into some software I'm familiar with the DEM file was in a binary format which I struggled with to ready into R so I started to work with the JPGs to read these in as raster image in R.  I faced a couple of roadblocks around how to query a bringing that back to latitudes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Eventually I came across the R Package: &lt;a href=&quot;https://cran.r-project.org/web/packages/rgbif/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;rgbif: Interface to the Global 'Biodiversity' Information Facility API&lt;/a&gt;&#xA;With this package you can query a specific lat &amp;amp; long and return the elevation in meters! also as a bonus you can get some biodiversity information.    It connects to the &lt;a href=&quot;http://www.geonames.org&quot; rel=&quot;nofollow noreferrer&quot;&gt;geonames database&lt;/a&gt; other software that has clients to connect to the data can be found &lt;a href=&quot;http://www.geonames.org/export/client-libraries.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;#Here is some R code for the POC:&#xA;#install.packages(&quot;rgbif&quot;)&#xA;library(rgbif)&#xA;&#xA;&#xA;#You need to sign up to your own Geonames account you get 1000 queries per hour for free max 30k per day&#xA;user &amp;lt;- Sys.getenv(&quot;GEONAMES_USER&quot;)&#xA;&#xA;#I take 15 points of latitude either side of the peak at 0.005 intervals&#xA;Latitude &amp;lt;-c(-17.3991666666667,-17.4041666666667,-17.4091666666667,-17.4141666666667,-17.4191666666667,-17.4241666666667,-17.4291666666667,-17.4341666666667,-17.4391666666667,-17.4441666666667,-17.4491666666667,-17.4541666666667,-17.4591666666667,-17.4641666666667,-17.4691666666667,-17.3941666666667,-17.3891666666667,-17.3841666666667,-17.3791666666667,-17.3741666666667,-17.3691666666667,-17.3641666666667,-17.3591666666667,-17.3541666666667,-17.3491666666667,-17.3441666666667,-17.3391666666667,-17.3341666666667,-17.3291666666667)&#xA;Longitude &amp;lt;-c(145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333,145.818333333333)&#xA;&#xA;#Use the elevation function to return the elevations&#xA;Bartle &amp;lt;- elevation(latitude=Latitude, longitude=Longitude, username = user)&#xA;&#xA;#Order my co-ordinates for the plot&#xA;Bartle &amp;lt;- Bartle[order(Bartle&lt;span class=&quot;math-container&quot;&gt;$latitude),]&#xA;plot(x=Bartle$&lt;/span&gt;latitude, y=Bartle&lt;span class=&quot;math-container&quot;&gt;$elevation_geonames, main = &quot;BARTLE FRERE, SOUTH PEAK&quot;)&#xA;lines(x=Bartle$&lt;/span&gt;latitude, y=Bartle&lt;span class=&quot;math-container&quot;&gt;$elevation_geonames) &#xA;polygon(cbind(c(min(Bartle$&lt;/span&gt;latitude), Bartle&lt;span class=&quot;math-container&quot;&gt;$latitude, max(Bartle$&lt;/span&gt;latitude)), c(min(Bartle&lt;span class=&quot;math-container&quot;&gt;$elevation_geonames), Bartle$&lt;/span&gt;elevation_geonames, min(Bartle$elevation_geonames))), col=&quot;#00CC66&quot;) &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JBQko.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JBQko.png&quot; alt=&quot;Bartel Frere Example&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I hope to work on this over the next couple of weeks and hope to update further - but here is the start just localised to &lt;a href=&quot;https://public.tableau.com/views/MountainsV2/GeographicView?:embed=y&amp;amp;:display_count=yes&amp;amp;publish=yes&quot; rel=&quot;nofollow noreferrer&quot;&gt;Australia&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zNmYA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zNmYA.png&quot; alt=&quot;Example of basic Tableau Viz&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks Again Camilo!&lt;/p&gt;&#xA;" OwnerUserId="15251" LastEditorUserId="15251" LastEditDate="2019-03-01T06:30:13.967" LastActivityDate="2019-03-01T06:30:13.967" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16362" PostTypeId="1" CreationDate="2019-02-28T23:52:35.967" Score="3" ViewCount="50" Body="&lt;p&gt;Paleontologist Michael J. Benton of the University of Bristol wrote: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;“​The aftermath of the great end-Permian period mass extinction 252 Myr ago shows how life can recover from the loss of &gt;90% species globally. The crisis was triggered by a number of physical environmental shocks (global warming, acid rain, ocean acidification and ocean anoxia), and some of these were repeated over the next 5–6 Myr. Ammonoids and some other groups diversified rapidly, within 1–3 Myr, but extinctions continued through the Early Triassic period. Triassic ecosystems were rebuilt stepwise from&#xA;  low to high trophic levels through the Early to Middle Triassic, and a stable, complex ecosystem did not re-emerge until the beginning of the Middle Triassic, 8–9 Myr after the crisis” &lt;a href=&quot;https://doi.org/10.1038/ngeo1475&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;According to the latest reports, marine ecosystems achieved a complete recovery at 244.5 ± 1 ​million years ago​, and recovery of terrestrial ecosystems is contemporaneous or later than marine ecosystems &lt;a href=&quot;https://doi.org/10.1016/j.epsl.2017.11.042&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can someone point to any research on recovery of the terrestrial ecosystems after the Permian extinction? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1038/ngeo1475&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;:Chen, Z. Q., Benton, M. J. “&lt;a href=&quot;https://doi.org/10.1038/ngeo1475&quot; rel=&quot;nofollow noreferrer&quot;&gt;The timing and pattern of biotic recovery&#xA;following the end-Permian mass extinction&lt;/a&gt;,” ​Nature Geoscience​, Volume 5, 2012&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1016/j.epsl.2017.11.042&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;: Li, M. ​et al, ​ “&lt;a href=&quot;https://doi.org/10.1016/j.epsl.2017.11.042&quot; rel=&quot;nofollow noreferrer&quot;&gt;Astrochronology of the Anisian stage (Middle Triassic) at the Guandao reference section, South China&lt;/a&gt;,” ​Earth and Planetary Science Letters, ​Volume 482, 2018; Luo, M. ​et al, ​ “&lt;a href=&quot;https://doi.org/10.1016/j.palaeo.2017.11.028&quot; rel=&quot;nofollow noreferrer&quot;&gt;Early Middle Triassic trace fossils from the Luoping Biota, southwestern China: Evidence of recovery from mass extinction&lt;/a&gt;,” Palaeogeography, Palaeoclimatology, Palaeoecology, ​ volume 515, 2019&lt;/p&gt;&#xA;" OwnerUserId="15299" LastEditorUserId="725" LastEditDate="2019-03-18T09:07:04.430" LastActivityDate="2019-03-18T09:07:04.430" Title="Recovery of terrestrial ecosystems after the end-Permian mass extinction?" Tags="|mass-extinction|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16364" PostTypeId="1" AcceptedAnswerId="16367" CreationDate="2019-03-01T05:12:43.973" Score="5" ViewCount="15307" Body="&lt;p&gt;Here is a measurement of CO2 concentration by altitude measured by aircraft:&lt;br /&gt;(from &lt;a href=&quot;https://www.researchgate.net/figure/In-situ-CO2-concentrations-versus-altitude-measured-by-the-DOE-Cessna-aircraft-with-an_fig12_227619523&quot; rel=&quot;noreferrer&quot;&gt;Pulsed airborne lidar measurements of atmospheric CO2 column absorption&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7whOW.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7whOW.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this the usual vertical structure of CO2? Why is it at a higher concentration close to the surface and then uniform at a certain point? &lt;/p&gt;&#xA;" OwnerUserId="7794" LastEditorUserId="595" LastEditDate="2019-03-01T08:08:08.433" LastActivityDate="2019-12-22T16:37:33.200" Title="What is the CO2 concentration by altitude and why?" Tags="|atmosphere|co2|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16366" PostTypeId="1" AcceptedAnswerId="16373" CreationDate="2019-03-01T16:50:45.100" Score="4" ViewCount="7091" Body="&lt;p&gt;I have a project for my school to make, and I'd like to have some materials of research/graphs of dependencies about how the weather is predicted (i.e. cloudy, sunny, rainy). I've been searching the internet for the past few days but couldn't find something rather helping.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can use an Arduino UNO and a bunch of sensors (i.e. atmospheric pressure, temperature, humidity, etc.), but my main problem is how to accurately interpret the parameters measured.&lt;/p&gt;&#xA;" OwnerUserId="15337" LastEditorUserId="11908" LastEditDate="2019-03-02T02:55:23.443" LastActivityDate="2022-02-09T21:53:47.200" Title="Weather forecast based on pressure, temperature and humidity only (for implementation in Arduino)" Tags="|weather-forecasting|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16367" PostTypeId="2" ParentId="16364" CreationDate="2019-03-01T17:20:25.413" Score="3" Body="&lt;p&gt;The volume of carbon dioxide in the atmospheric column becomes uniform at altitude because the sources and sinks for CO2 are generally at ground level and, as it rises, CO2 becomes well-mixed into the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is why, for example, &lt;a href=&quot;https://scripps.ucsd.edu/programs/keelingcurve/2013/04/03/the-history-of-the-keeling-curve/&quot; rel=&quot;nofollow noreferrer&quot;&gt;David Keeling began the measurements for what would become known as the Keeling Curve at a station 3.3 kilometers above ground level at Mauna Loa.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At ground level, CO2 levels will be heavily influenced by local and seasonal sources such as forests, grasslands, and human activity. That is, if you have a city or industrial area, CO2 emissions will be high due to the burning of fossil fuels. In the case of nature, forests and grasslands will absorb CO2 during the local spring and summer when they grow and emit CO2 in fall and winter as they decompose. (Seen in the annual wiggles in the generally rising Keeling Curve.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gJIVA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gJIVA.png&quot; alt=&quot;Keeling Curve showing general rise, annual wiggles&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The specifics will vary by location. In the case of your graph, this late-fall test proofing lidar against balloon measurements over Oklahoma on Dec. 7, 2008 shows CO2 at about 395 ppm at about a half a kilometer, declining with altitude so that at about 3.3km, the measurement is around 385-386ppm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At Mauna Loa, at 3.3km, the &lt;a href=&quot;https://www.co2.earth/monthly-co2&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA monthly CO2 data&lt;/a&gt; average for December 2008 was 385.56ppm.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastEditorUserId="7314" LastEditDate="2019-03-03T06:26:51.660" LastActivityDate="2019-03-03T06:26:51.660" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16368" PostTypeId="1" CreationDate="2019-03-01T18:54:50.243" Score="2" ViewCount="341" Body="&lt;p&gt;Does any mineral crystallize in the shape of an oblique square prism? If so, what crystal system (monoclinic, cubic, hexagonal, etc.) would such a mineral fall under? &lt;/p&gt;&#xA;" OwnerUserId="15338" LastActivityDate="2019-03-20T18:52:42.273" Title="An oblique-square-prism crystal?" Tags="|geology|mineralogy|minerals|crystals|crystallography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16369" PostTypeId="2" ParentId="13042" CreationDate="2019-03-01T19:29:30.233" Score="7" Body="&lt;p&gt;Trace fossils are marks or things left behind by living things do their thing,  they are indirect remains of organisms, coprolites (poop), footprints, egg shells, ect. If we found a fossilized beehive or beaver dam those would also be trace fossils. Bioturbation is a specific type of traces fossil, marks of disturbances of the sediment itself animals leave behind, trackways and burrows are the classics.&lt;/p&gt;&#xA;&lt;p&gt;Identifying bioturbation is tricky in a lot of cases, there are thousands of kinds which makes it worse, there is no way to give a direct answer. Your best bet is to find out what particular bioturbation they are referring to.  Burrows, trackways, feeding trails, nest, hold marks the list is endless. there are nearly as many trace fossils as there are organisms that crawl or dig.  Worse they are often very contextual and need examination of  micro-structure.  What is obvious a trace fossil in one formation will look identical to the naked untrained eye to something that is obviously not a trace fossil in a different formation. Generally you want to a specialized experts opinion before if saying something might be bioturbation someplace you don't expect it.&lt;/p&gt;&#xA;&lt;p&gt;Even from a single location you can have a wide variety of forms,  here are a few &lt;a href=&quot;https://www.researchgate.net/publication/284585442_Ordovician_trace_fossils_of_Argentina&quot; rel=&quot;nofollow noreferrer&quot;&gt;examples&lt;/a&gt; from the ordovician, &lt;a href=&quot;https://en.wikipedia.org/wiki/Ordovician&quot; rel=&quot;nofollow noreferrer&quot;&gt;...the second of six periods of the Paleozoic Era, 485.4–443.8 million years ago&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Bioturbation&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/c2FjC.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/c2FjC.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/9oIJX.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9oIJX.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The photos from mars are not likely to be bioturbation but are almost certainly differential erosion of normal chemical variation in rock. They do not have any of the characteristics that scream &amp;quot;this has to be biological activity&amp;quot; like cross cutting bedding planes or parallel patterns. Sedimentary rocks are rarely homogenous and chemical processes combine with erosional ones can produce some weird results. for comparison here are a few things that are definitely NOT fossils.&lt;/p&gt;&#xA;&lt;p&gt;**Pseudofossils AKA Leaverite **&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gYecr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gYecr.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iJ1mb.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iJ1mb.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Pseudofossils are things lake look like fossils to the untrained eye but are just rocks, usually the leftovers of a chemical or erosional process. the term leaverite comes from geologists telling others &amp;quot;just leave're there&amp;quot;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-03-02T04:13:17.543" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16371" PostTypeId="1" CreationDate="2019-03-01T20:05:18.287" Score="1" ViewCount="2542" Body="&lt;p&gt;I have read different statistics on residential water use. One EPA chart I saw had residential use of water taking up half of all water, which seems unbelievable to me. Another writer claimed that only 1% of water is used by residential consumers. Quite a big difference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One statistic I saw said that 45% of water &quot;withdrawals&quot; was for thermoelectric power, but presumably water can still be used by other consumers after it has gone through a dam power plant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we split water use between (1) residential consumption, (2) agricultural irrigation, (3) industrial consumption, and (4) commercial business consumption, there would seem to be four basic types of consumers. What is the relative balance of water consumption between these four types?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2019-03-02T13:48:57.803" Title="How much water gets consumed by residential use versus all other uses?" Tags="|water|united-states|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16372" PostTypeId="2" ParentId="16371" CreationDate="2019-03-01T20:29:19.323" Score="2" Body="&lt;p&gt;Dams are hydroelectric, thermoelectric is something else. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thermoelectric refers to water extracted to boil to power a generator or used to cool the fluid used in said generator, In the US mostly coal, gas, and fuel oil plants but other ones like geothermal, nuclear, and mass solar also count, basically if it works off heat it consumes water (thermo- literally means heat). Much of this water of course evaporates. And yes it is quite high. About the same as we extract for irrigation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/F2wel.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/F2wel.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;a href=&quot;https://water.usgs.gov/watuse/wuto.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://water.usgs.gov/watuse/wuto.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Public water (purple), can be further divided, the &lt;a href=&quot;https://water.usgs.gov/watuse/wups.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS&lt;/a&gt; estimates public use as follows. You'll note no differentiation is made between commercial and industrial. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ceWuu.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ceWuu.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wikipedia actually has a decent &lt;a href=&quot;https://en.wikipedia.org/wiki/Nonresidential_water_use_in_the_U.S.&quot; rel=&quot;nofollow noreferrer&quot;&gt;entry&lt;/a&gt; with further EPA estimate breakdowns, if you want to dive further. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2019-03-02T13:48:57.803" LastActivityDate="2019-03-02T13:48:57.803" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16373" PostTypeId="2" ParentId="16366" CreationDate="2019-03-02T02:48:13.447" Score="9" Body="&lt;p&gt;Such simple algorithms are empirical and for the same reason very local, so depending on your location they can have very bad performance. In the other hand, some people argue that properly calibrated they can be &lt;a href=&quot;https://web.archive.org/web/20110610213848/http://www.meteormetrics.com/zambretti.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;over 90%&lt;/a&gt; accurate.&lt;/p&gt;&#xA;&lt;p&gt;Most of them are based in the Zambretti algorithm or some variant of it. This algorithm was originally implemented in a forecaster device produced by the firm Negretti and Zambra in the early XX century.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jfAuY.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jfAuY.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It considers the absolute value of the pressure, the trend of the pressure, the season and the wind direction (although wind direction and season have a small impact in the output). The algorithm is well described and translated to formulas in &lt;a href=&quot;https://web.archive.org/web/20110610213848/http://www.meteormetrics.com/zambretti.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt;, but in summary it works calculating a tabulated forecast number &lt;span class=&quot;math-container&quot;&gt;$Z$&lt;/span&gt; as follows:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;From your measured pressure &lt;span class=&quot;math-container&quot;&gt;$P$&lt;/span&gt;, temperature in Celsius &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; and the altitude in meters &lt;span class=&quot;math-container&quot;&gt;$h$&lt;/span&gt; compute the atmospheric pressure reduced to sea level &lt;span class=&quot;math-container&quot;&gt;$P_0$&lt;/span&gt;. There are many formulas for this, a common one is:&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$P_0=P\left(1-\frac{0.0065 h}{T + 0.0065 h+ 273.15}\right)^{-5.257}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;Compute the pressure trend and&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;If the pressure is &lt;strong&gt;falling&lt;/strong&gt; compute the forecast number as &lt;span class=&quot;math-container&quot;&gt;$Z = 130-\frac{P_0}{81}$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;If the pressure is &lt;strong&gt;steady&lt;/strong&gt; compute the forecast number as &lt;span class=&quot;math-container&quot;&gt;$Z = 147 -\frac{5 P_0}{376}$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;If the pressure is &lt;strong&gt;rising&lt;/strong&gt; compute the forecast number as &lt;span class=&quot;math-container&quot;&gt;$Z = 179-\frac{2 P_0}{129}$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;Adjust &lt;span class=&quot;math-container&quot;&gt;$Z$&lt;/span&gt; for wind direction:&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;For Northerly winds adjust &lt;span class=&quot;math-container&quot;&gt;$Z=Z+1$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;For Southerly winds adjust &lt;span class=&quot;math-container&quot;&gt;$Z=Z-2$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;ol start=&quot;4&quot;&gt;&#xA;&lt;li&gt;Adjust &lt;span class=&quot;math-container&quot;&gt;$Z$&lt;/span&gt; for the season:&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;If Winter and pressure is falling, adjust: &lt;span class=&quot;math-container&quot;&gt;$Z=Z-1$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;If Summer and pressure is rising, adjust: &lt;span class=&quot;math-container&quot;&gt;$Z=Z+1$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;ol start=&quot;5&quot;&gt;&#xA;&lt;li&gt;Look up for the forecast from the following table:&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WCUeP.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WCUeP.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This was made for the UK, and many people have developed modified version to work in other areas. You will find many implementations online with downloadable code, as &lt;a href=&quot;http://www.beteljuice.co.uk/zambretti/forecast.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one in javascript&lt;/a&gt;, or &lt;a href=&quot;https://github.com/fandonov/weatherstation&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one in C for Arduino UNO&lt;/a&gt;, an explanation of this Arduino UNO implementation can be found &lt;a href=&quot;https://cdn.hackaday.io/files/274581174763072/english_description.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2022-02-09T21:53:47.200" LastActivityDate="2022-02-09T21:53:47.200" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16375" PostTypeId="2" ParentId="8230" CreationDate="2019-03-02T03:38:54.717" Score="-5" Body="&lt;ol&gt;&#xA;&lt;li&gt;The Tower of London was built during this period on the banks of the Thames  River level is the same today as it was then.&lt;/li&gt;&#xA;&lt;li&gt;People seem to forget that the Anasazi in SW America disappeared during this same period due to prolonged drought so there was no food to eat.&lt;/li&gt;&#xA;&lt;li&gt;The Chinese also have three hundred years of weather records recording changes in their weather as well. Particularly, an increase in rainfall during the peak of the European temperature increases.&lt;/li&gt;&#xA;&lt;li&gt;Tree rings in North American West show a slow down in growth.&#xA;So when “warmers” try to say that the weather changes during this period of time was a local occurrence they, as usual, don’t know what the hell they are talking about.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="15342" LastEditorUserId="725" LastEditDate="2019-03-04T10:12:52.050" LastActivityDate="2019-03-04T10:12:52.050" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16376" PostTypeId="2" ParentId="13440" CreationDate="2019-03-02T04:25:05.843" Score="8" Body="&lt;p&gt;&lt;strong&gt;Short answer&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Different plants reflect light at different wavelengths with specific patterns. If you know the reflection pattern of a broad-leaved forest and that of a needle-leaved forest, you can compare them with the pattern observed with a satellite and conclude to which forest it is more similar.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Long answer&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Optical remote sensing&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Optical sensors record electromagnetic radiation at different wavelengths between 400 and 2400 nanometers. This radiation came from the sun and impacting surfaces of different materials on Earth surface is either absorbed by, transmitted through or scattered back. The amount of radiation that is scattered back is then detected and recorded by an Earth-Observing sensor such as MERIS', MODIS' or Landsat's. Due to chemical and physical properties of different materials, they can absorb, transmit and reflect different proportions of radiation at each wavelength. The reflectance recorded by a sensor for a pure material is called spectral signature. This signature is often unique for a material. This can help identify the presence of different materials on the Earth surface when a spectral signature is known.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the laboratory, with more sophisticated and accurate sensors, is possible to identify the spectral pattern of single pure chemical compounds or molecules. However, if we scale up and consider the spectral response of a whole forest, you can easily imagine how everything gets mixed up: the spectral signature of many pure molecules in different proportions, scattered back and forth in more or less dense and geometrically various canopies are all sensed by a single sensor unit (for example, one pixel of our satellite image).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Estimating the presence and amount of different materials on the heterogeneous Earth surface becomes a very complex problem and researchers have found many a method to partially overcome it and obtain reasonably accurate estimations of what covers Earth surface and in which amount.&#xA;Predominantly, 1) the observed mixed spectral response of a material is statistically linked to in situ measurements, or 2) the spectral response of mixed materials is simulated with computational models and is statistically compared with the observed one. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In both cases, it is possible to use the whole spectral signature or specific metrics derived from specific regions of the spectrum, that we know are related to the presence of some substance that is related to what we are trying to describe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The spectral properties of plants&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The spectral properties of plants have received quite the interest in the past 50 years and one undeniable spectral feature that all green vegetation has, that substantially differentiates it from that of soils, rocks, artificial materials and water is the so-called red-edge. The red-edge is characterised by a low reflectance in the visible radiation (due to chlorophyll absorption) and a high reflectance in the near infrared region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Normalised Difference Vegetation Index (NDVI) is one of the many metrics proposed to quantify the red-edge feature. The index is very simple and needs only two bands and no site-specific adjusting constants:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;NDVI = (Red-NIR)/(Red+NIR)&#xA;Red = reflectance of the red radiation&#xA;NIR = reflectance of the near infrared radiation&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Since its simplicity, the NDVI is probably the single most used index in optical remote sensing of the vegetation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The NDVI is a metric for the red-edge feature and thus it is influenced by chlorophyll activity and the presence of other vegetative tissues. And it was successfully (empirically) related to the phenologic stage, plant health, biomass and leaf area index.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In conclusion, if you know the expected spectral signature of a pine forest and that of an oak forest, you can compare them with the spectral signature of any pixel you observe and estimate to which forest the pixel's spectral signature is the most similar. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clearly, the NDVI can be used for that comparison rather than the whole signature due to its simplicity and versatility; additionally, its interannual patterns can differentiate between annual and perennial, and evergreen and deciduous forests.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, depending on the resolution of the sensor and the scope of the project, more metrics are possible and different classification methods become available.&#xA;There are several other features that have been identified in plant spectral response. For example, the lignin, starch, cellulose and water absorption features in the short wave infrared.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have a look at the image below, you can notice that even the age between needles is differentiable by the spectral signature detected by very high spectral resolution sensors. Such sensors are typically handheld while satellite sensors commonly have between 5 and 15 points where you see a continuous line below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image from: &lt;a href=&quot;https://www.mdpi.com/2072-4292/10/2/207/htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rautiainen, M., Lukeš, P., Homolová, L., Hovi, A., Pisek, J., &amp;amp; Mõttus, M. (2018). Spectral Properties of Coniferous Forests: A Review of In Situ and Laboratory Measurements. Remote Sensing, 10&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LHvK8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LHvK8.png&quot; alt=&quot;from the paper: Spectral Properties of Coniferous Forests: A Review of In Situ and Laboratory Measurements&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15341" LastEditorUserId="15341" LastEditDate="2019-03-19T05:22:57.663" LastActivityDate="2019-03-19T05:22:57.663" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16377" PostTypeId="1" AcceptedAnswerId="16378" CreationDate="2019-03-02T17:32:28.220" Score="7" ViewCount="334" Body="&lt;p&gt;The uncertainty in the half life of uranium-238 is stated at 0.05% [1]. The same paper gives the date 251.941 myr ± 31 kyr. &#xA;251.941 &lt;span class=&quot;math-container&quot;&gt;$\times$&lt;/span&gt; 0.05% = 125 kyr. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How are the authors justified in claiming an accuracy of ± 31 kyr when the uncertainty in the half life alone is ± 125 kyr? On top of that, they list two other kinds of analytical uncertainties, which would only increase the overall uncertainty. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1] ​ Burgess, S. ​et al​, &quot;High-precision timeline for Earth’s most severe extinction&quot;, Proceedings of the National Academy of Sciences USA​, Volume 111, 2014.&#xA;&lt;a href=&quot;https://www.pnas.org/content/pnas/111/9/3316.full.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.pnas.org/content/pnas/111/9/3316.full.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15299" LastEditorUserId="11908" LastEditDate="2019-03-11T20:57:57.020" LastActivityDate="2022-03-17T23:38:42.443" Title="Unwarranted claim of higher degree of accuracy in zircon geochronology" Tags="|geophysics|measurements|mass-extinction|geochronology|uranium|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16378" PostTypeId="2" ParentId="16377" CreationDate="2019-03-02T20:00:09.693" Score="10" Body="&lt;p&gt;I can't be entirely sure but I'll make an informed guess:&lt;/p&gt;&#xA;&lt;p&gt;That value doesn't come for a single measurement. Therefore, if the error in the age of a single sample is &lt;span class=&quot;math-container&quot;&gt;$\pm125$&lt;/span&gt; kyr, you just need to average 16 samples to get it down to &lt;span class=&quot;math-container&quot;&gt;$\pm31$&lt;/span&gt; kyr.&lt;/p&gt;&#xA;&lt;p&gt;The uncertainty in the addition (or substraction) of two or more quantities is equal to the square root of the addition of the squares of the uncertainties of each quantity (assuming they arise from random errors). For example, if we have quantity A with uncertainty &lt;span class=&quot;math-container&quot;&gt;$\sigma_a$&lt;/span&gt; and quantity B with uncertainty &lt;span class=&quot;math-container&quot;&gt;$\sigma_b$&lt;/span&gt;, the error in the quantity &lt;span class=&quot;math-container&quot;&gt;$C=A+B$&lt;/span&gt; would be:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\sigma_c=\sqrt{\sigma_a^2+\sigma_b^2}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;And if we call M to the average between A and B. The uncertainty in the average is&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\sigma_m=\frac{\sqrt{\sigma_a^2+\sigma_b^2}}{2}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;So if we average 16 samples with &lt;span class=&quot;math-container&quot;&gt;$\sigma=125$&lt;/span&gt; kyr, the uncertainty in the average would be&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\sigma_m=\frac{\sqrt{16 \sigma^2}}{16}=\frac{\sqrt{16 \times 125^2}}{16}=31$&lt;/span&gt; kyr&lt;/p&gt;&#xA;&lt;p&gt;Uncertainty propagation can be seen in the abstract of the article you refer to:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The extinction occurred between 251.941 ± 0.037 and 251.880 ± 0.031&#xA;Mya, an interval of 60 ± 48 ka.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Where the ±48 ka comes from?&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\sqrt{37^2+31^2}=48$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;This treatment of uncertainties assumes that uncertainties are independent of each other. As @Mark pointed in the comments, this won't be the case if the uncertainty comes from &amp;quot;the length of your measuring stick (the half-life of U-238)&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;This is: if you measure something with a &amp;quot;yard-stick&amp;quot; that have the wrong size, you can't reduce the resulting error by just averaging many measurements.&lt;/p&gt;&#xA;&lt;p&gt;I don't know enough of geochronology to understand all the different errors they report. But the simple example in the abstract cite I presented above shows that they are indeed treating those errors as independent. Otherwise the reported interval error (±48 ka) would not make sense.&lt;/p&gt;&#xA;&lt;p&gt;If one significant source of error is indeed the uncertainty in the half-life of &lt;span class=&quot;math-container&quot;&gt;$^{238}$&lt;/span&gt;U, it would be wrong to treat these errors as independent. Such an assumption would be right only if there exists an exact value for this half-life. Alternatively, maybe there is no exact value of the half-life, and what they meant is that the half-life value can truly vary a 0.05%. This is something to look into if you want to figure out if the treatment of errors they do is correct. However, after a quick google search I found that radioactive half-life can indeed vary by a small fraction due to environmental conditions, &lt;a href=&quot;http://wtamu.edu/%7Ecbaird/sq/2015/04/27/can-the-decay-half-life-of-a-radioactive-material-be-changed/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; explains pretty well the phenomena. Here a short excerpt:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;...radioactive half-life of an atom can depend on how it is bonded to&#xA;other atoms. Simply by changing the neighboring atoms that are bonded&#xA;to a radioactive isotope, we can change its half-life. However, the&#xA;change in half-life accomplished in this way is typically small. For&#xA;instance, a study performed by B. Wang et al and published in the&#xA;European Physical Journal A was able to measure that the electron&#xA;capture half-life of beryllium-7 was made 0.9% longer by surrounding&#xA;the beryllium atoms with palladium atoms.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;If the 0.05% uncertainty on the half-life of &lt;span class=&quot;math-container&quot;&gt;$^{238}$&lt;/span&gt;U comes from random environmental factors, it would indeed be acceptable to consider them as an independent/random source of error for each sample.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2022-03-17T23:38:42.443" LastActivityDate="2022-03-17T23:38:42.443" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="16380" PostTypeId="2" ParentId="8230" CreationDate="2019-03-02T20:22:35.593" Score="3" Body="&lt;p&gt;&lt;a href=&quot;http://www.realclimate.org/index.php/archives/2016/02/millennia-of-sea-level-change/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; based on 2016 publications shows a global decline during 950 to 1250.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/vnOAc.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vnOAc.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Fig. 1 Reconstruction of the global sea-level evolution based on proxy data from different parts of the world. The red line at the end (not included in the paper) illustrates the further global increase since 2000 by 5-6 cm from satellite data.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There may be local differences due to isostatic rebound but these happen on much longer timescales.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-03-02T20:22:35.593" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16383" PostTypeId="1" CreationDate="2019-03-02T23:23:35.400" Score="1" ViewCount="27" Body="&lt;p&gt;I recently saw a great &lt;a href=&quot;https://www.ted.com/talks/allan_savory_how_to_green_the_world_s_deserts_and_reverse_climate_change&quot; rel=&quot;nofollow noreferrer&quot;&gt;talk&lt;/a&gt; by Allan Savory, the pioneering ecologist about holistic management of cattle grazing to prevent desertification of grasslands. He claimed that it is the only viable way for mitigating damages due to climate change. Is this claim supported by scientific studies in this area and how does it compare with methods like carbon capture and storage?&lt;/p&gt;&#xA;" OwnerUserId="15348" LastActivityDate="2019-03-02T23:23:35.400" Title="How does planned cattle grazing compare with other methods (like carbon capture) of mitigating climate change?" Tags="|climate-change|ecology|" AnswerCount="0" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16384" PostTypeId="2" ParentId="14348" CreationDate="2019-03-03T03:18:37.837" Score="2" Body="&lt;p&gt;No. Not in a significant way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The full width at half maximum (FWHM) of a spectral line widened by thermal &lt;a href=&quot;https://en.wikipedia.org/wiki/Doppler_broadening&quot; rel=&quot;nofollow noreferrer&quot;&gt;Doppler broadening&lt;/a&gt; is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\Delta f_{\text{FWHM}}={\sqrt{\frac{8kT\ln(2)}{mc^{2}}}}f_{0}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt; is the mass of the emitting particle, &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; is the temperature, &lt;span class=&quot;math-container&quot;&gt;$f_{0}$&lt;/span&gt; is the frequency of the spectral line, and &lt;span class=&quot;math-container&quot;&gt;$k$&lt;/span&gt; is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Boltzmann_constant&quot; rel=&quot;nofollow noreferrer&quot;&gt;Boltzmann constant&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's look at the CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; absorption lines:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/REexQ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/REexQ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Image from Wikipedia commons, &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Atmospheric_Transmission.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's take for example the band roughly between 12 and 20 &lt;span class=&quot;math-container&quot;&gt;$\mu m$&lt;/span&gt;. That corresponds to frequencies from 15 to 25 THz, with a mean of 20 THz.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we solve the above equation for the mass of a CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; molecule (&lt;span class=&quot;math-container&quot;&gt;$44.01/6.02\times 10^{23}$&lt;/span&gt; g), a frequency of 20 THz and an Earth's mean temperature of let's say 15°C (288.15 K) we get 1158 kHz broadening, and for an scenario 2°C warmer it would be 1162 kHz.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, the width of the absorption band would grow 8 kHz (4 kHz on either side). Which considering the original width of 10 THz &lt;strong&gt;corresponds to a 0.00008% increase&lt;/strong&gt;. This could be roughly equated to an analogous increase in absorbed energy, &lt;strong&gt;which is absolutely negligible for all practical effects&lt;/strong&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-03-03T03:18:37.837" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16385" PostTypeId="2" ParentId="13912" CreationDate="2019-03-03T08:09:45.510" Score="5" Body="&lt;p&gt;When electromagnetic waves travel through a medium, it can interact with the medium in question. But that interaction depends on the electric properties of the medium. &#xA;Ice, being a dielectric medium, do interact with the incident e.m. wave from the sensor.&#xA;The penetration depth is directly proportional to the wavelength of the radiation used (there are different forms in which this depth can be expressed but the easiest for me to remember is Eq 2.14 of the Fundamentals of Remote Sensing by George Joseph; &lt;a href=&quot;https://books.google.ca/books?id=peUFLCy4zLYC&amp;amp;printsec=frontcover&amp;amp;source=gbs_atb#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;available in Google Book as well&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$l_a=\frac{\lambda_0 \sqrt{\varepsilon'}}{2 \pi \varepsilon''}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where &lt;span class=&quot;math-container&quot;&gt;$l_a$&lt;/span&gt; is the penetration depth in ice, defined as the depth at wich the signal power falls to &lt;span class=&quot;math-container&quot;&gt;$1/e$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\varepsilon'$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\varepsilon''$&lt;/span&gt; are respectively the real and imaginary parts of the dielectric constant, and &lt;span class=&quot;math-container&quot;&gt;$\lambda_0$&lt;/span&gt; is the free space wavelength of the electromagnetic radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And so, the microwave radiation (higher wavelength radiations in the electromagnetic spectrum) used in ground penetrating radar can penetrate through the ice surface, the depth thru which it can penetrate being given by the same equation mentioned above.&#xA;Cheers.&lt;/p&gt;&#xA;" OwnerUserId="15349" LastEditorUserId="11908" LastEditDate="2019-03-03T18:00:23.087" LastActivityDate="2019-03-03T18:00:23.087" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16388" PostTypeId="2" ParentId="8496" CreationDate="2019-03-03T17:40:26.680" Score="2" Body="&lt;p&gt;There is no &quot;standard volcano&quot; or &quot;standard volcanic eruption&quot;. However, to perform the calculation you want to do, you could use the &quot;typical&quot; of &quot;average&quot; volcanic eruption. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The characteristics of the &quot;average&quot; volcanic eruption can be found by calculating the average parameters of many volcanic eruptions. Such averages are not often reported, because the variability of volcanic eruption sizes and compositions is so large that averaging them doesn't makes much sense. But it does for your very particular application. So let's try to estimate how the &quot;typical&quot; volcanic eruption looks like:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's first figura out the typical volume of ejecta produced by a volcanic eruption: this is usually measured by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Volcanic_Explosivity_Index&quot; rel=&quot;nofollow noreferrer&quot;&gt;VEI (Volcanic Explosivity Index)&lt;/a&gt;, and the formula to turn VEI into volume is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\text{Ejecta volume}=10^{-4+\text{VEI}} \, \text{km}^3$&lt;/span&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we download NOAA's &lt;a href=&quot;https://www.ngdc.noaa.gov/nndc/servlet/ShowDatasets?dataset=102557&amp;amp;search_look=50&amp;amp;display_look=50&quot; rel=&quot;nofollow noreferrer&quot;&gt;Significant Volcanic Eruption Database&lt;/a&gt;, it contains 646 recorded eruptions from 1750 to the present, and 498 of them have reported VEI values. Computing the volume ejected by each eruption (using the above formula) and taking the average we get that the &quot;typical&quot; eruption produces 3.2 km&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt; of ejecta.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using an &lt;a href=&quot;http://pages.mtu.edu/~raman/papers2/WilsonSelf80JGR.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;average density of volcanic ejecta of 2 g/cm&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt;&lt;/a&gt;, this average volume corresponds to &lt;span class=&quot;math-container&quot;&gt;$6.4 \times 10^{12}$&lt;/span&gt; g or 6,400,000 tons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In typical magma, &lt;a href=&quot;http://www.indiana.edu/~volcano/notes/handout2.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;about 0.5% of its mass corresponds to gases&lt;/a&gt;, and for our &quot;typical&quot; mass that would corresponds to &lt;span class=&quot;math-container&quot;&gt;$3.2 \times 10^{10}$&lt;/span&gt; g or &lt;strong&gt;32,000 tons of gases in a &quot;typical&quot; volcanic eruption&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, &lt;a href=&quot;https://www.geolsoc.org.uk/ks3/gsl/education/resources/rockcycle/page3601.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;about 7% of the gases corresponds to SO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;&lt;/a&gt;. That means that 0.035% of the mass of the ejecta is SO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;, and for our &quot;typical&quot; mass that would corresponds to &#xA;&lt;span class=&quot;math-container&quot;&gt;$2.24 \times 10^9$&lt;/span&gt; g or &lt;strong&gt;2,240 tons of SO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; in a &quot;typical&quot; volcanic eruption&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you will see if you follow my references, I've pulled the above figures from multiple sources with varying degrees of reliability. Therefore, if you want a more precise estimate you can search for more accurate and updated values and repeat the exercise.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-03-03T20:20:58.650" LastActivityDate="2019-03-03T20:20:58.650" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16390" PostTypeId="1" CreationDate="2019-03-03T22:41:41.883" Score="1" ViewCount="25" Body="&lt;p&gt;Accelerographs measure ground acceleration in three different components of motion: east-west, north-south, and vertically (up-down). I know that fault orientation is important here, so let's say we are dealing with a thrust fault. If an accelerograph shows greater ground acceleration in the north-south direction (greater than east-west ground acceleration), then could one assume that the fault which caused an earthquake is spatially oriented with north-south or east-west attitude? &lt;/p&gt;&#xA;" OwnerUserId="14308" LastEditorUserId="14308" LastEditDate="2019-03-04T01:57:21.653" LastActivityDate="2019-03-04T01:57:21.653" Title="Determining the spatial orientation of a fault given ground acceleration magnitude in different directions" Tags="|geophysics|seismology|tectonics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16392" PostTypeId="1" AcceptedAnswerId="19122" CreationDate="2019-03-04T03:06:50.543" Score="3" ViewCount="352" Body="&lt;p&gt;According to &lt;a href=&quot;https://www.cbsnews.com/news/geoengineering-treatment-stratospheric-aerosol-injection-climate-change-study-today-2018-11-23/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geoengineering treatment stratospheric aerosol injection climate change study&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Planes spraying tiny sulphate particulates into the lower&#xA;  stratosphere, around 60,000 feet up. The idea is to help shield the&#xA;  Earth from just enough sunlight to help keep temperatures low.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The researchers examined how practical and costly a hypothetical solar&#xA;  geoengineering project would be beginning 15 years from now. The aim&#xA;  would be to half the temperature increase caused by heat-trapping&#xA;  greenhouse gases.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Can spraying these sulphate particulates in the upper atmosphere to lower Earth's temperature have side effects?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastActivityDate="2020-02-05T05:35:00.170" Title="Can spraying sulphate particulates in the upper atmosphere to lower Earth's temperature have side effects?" Tags="|atmosphere|climate-change|geoengineering|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16394" PostTypeId="1" CreationDate="2019-03-04T10:07:37.950" Score="1" ViewCount="85" Body="&lt;p&gt;How can a nearly pure silica bed with 250 m x 50 m x 1.5 m dimensions be interpreted in a volcanic/pyroclastic setting? Here is a photo of it.&lt;a href=&quot;https://i.stack.imgur.com/ExcyK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ExcyK.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T11:56:13.493" LastActivityDate="2019-08-29T11:56:13.493" Title="Interpreting an outcrop of a thick pure silica bed in a volcanic setting" Tags="|volcanology|pyroclastic-flows|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16395" PostTypeId="1" CreationDate="2019-03-04T11:29:39.300" Score="4" ViewCount="296" Body="&lt;p&gt;how can a asterisk/star like crack occur on a hard pyroclastic rock? Could it caused by a meteroite or by some other mechanism?   You may see the shape of the rock on attached photo.&lt;a href=&quot;https://i.stack.imgur.com/IUoQM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IUoQM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T08:20:23.577" LastActivityDate="2020-08-03T01:23:31.517" Title="how can a asterisk/star like crack occur on a rock?" Tags="|geology|petrology|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16397" PostTypeId="2" ParentId="16395" CreationDate="2019-03-05T00:03:08.887" Score="1" Body="&lt;p&gt;Radial fracture is fairly common. It can form from cooling, drying mud, chemical shrinkage, impact, or several other means.  Since you are looking at volcanics you are probably looking at cooling shrinkage, The interior cools slower which means it shrinks more and that's how your get radial fractures. Fractures form perpendicular to whatever the cooling front shape is, a round shaped lava flow produces radial fractures. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.528.4436&amp;amp;rep=rep1&amp;amp;type=pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2019-03-06T15:13:54.093" LastActivityDate="2019-03-06T15:13:54.093" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16398" PostTypeId="1" CreationDate="2019-03-05T01:24:01.393" Score="1" ViewCount="56" Body="&lt;p&gt;I'm looking for a study or document  showing the effect of the topography, slopes, the sea level and the tide on flash flooding occurrence. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks in advance&lt;/p&gt;&#xA;" OwnerUserId="15360" LastActivityDate="2019-03-05T01:24:01.393" Title="Topography and flash flooding" Tags="|meteorology|sea-level|tides|flooding|topography|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16400" PostTypeId="1" CreationDate="2019-03-05T03:07:47.710" Score="6" ViewCount="291" Body="&lt;p&gt;Wikipedia's &lt;a href=&quot;https://en.wikipedia.org/wiki/Xenon#Occurrence_and_production&quot; rel=&quot;nofollow noreferrer&quot;&gt;Xenon; occurrence and production&lt;/a&gt; says&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Within the Solar System, the nucleon fraction of xenon is &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{1.56 \times 10^{-8}}$&lt;/span&gt;, for an abundance of approximately one part in 630 thousand of the total mass. Xenon is relatively rare in the Sun's atmosphere, on Earth, and in asteroids and comets. The abundance of xenon in the atmosphere of planet Jupiter is unusually high, about 2.6 times that of the Sun. This abundance remains unexplained, but may have been caused by an early and rapid buildup of planetesimals—small, subplanetary bodies—before the heating of the presolar disk. (Otherwise, xenon would not have been trapped in the planetesimal ices.) &lt;strong&gt;The problem of the low terrestrial xenon may be explained by covalent bonding of xenon to oxygen within quartz&lt;/strong&gt;, reducing the outgassing of xenon into the atmosphere.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I know that crystals can provide unusual amounts of local pressure. For example, &lt;a href=&quot;https://space.stackexchange.com/a/33570/12102&quot;&gt;this answer&lt;/a&gt; explains that ice VII has been discovered at room temperature as inclusions in diamonds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; But I'm still surprised to read about covalent bonding of xenon with oxygen within quartz. How/where has this been observed in naturally occurring mineral or rock, and what is the evidence of covalent bonding?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="2470" LastEditDate="2020-01-02T19:20:22.513" LastActivityDate="2020-07-11T13:43:23.767" Title="Does Xenon really covalently bond to oxygen within quartz?" Tags="|geochemistry|crystals|crystallography|gas|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16401" PostTypeId="2" ParentId="16400" CreationDate="2019-03-05T03:17:47.573" Score="5" Body="&lt;p&gt;Not sure this is appropriate for Earth Science SE (Chemistry SE would be a better fit), but the answer is &amp;quot;maybe&amp;quot;.  quoting from &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Xenon&quot; rel=&quot;nofollow noreferrer&quot;&gt;the same Wikipedia article&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Three oxides of xenon are known: xenon trioxide (&lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{XeO_3)}$&lt;/span&gt; and xenon&#xA;tetroxide &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{(XeO_4)}$&lt;/span&gt;, both of which are dangerously explosive and powerful&#xA;oxidizing agents, and &lt;strong&gt;xenon dioxide &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{(XeO_2)}$&lt;/span&gt;&lt;/strong&gt;, which was reported in&#xA;2011 with a coordination number of four.[97] &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{XeO_2}$&lt;/span&gt; forms when xenon&#xA;tetrafluoride is poured over ice. &lt;strong&gt;Its crystal structure may allow it&#xA;to replace silicon in silicate minerals.[98]&lt;/strong&gt; The &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{XeOO^+}$&lt;/span&gt; cation has&#xA;been identified by infrared spectroscopy in solid argon.[&lt;a href=&quot;https://pubmed.ncbi.nlm.nih.gov/21341650/&quot; rel=&quot;nofollow noreferrer&quot;&gt;99&lt;/a&gt;]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Cited references&lt;/p&gt;&#xA;&lt;p&gt;97.&#xA;Bell, C.F. (2013). Syntheses and Physical Studies of Inorganic Compounds. Elsevier Science. p. 143. ISBN 9781483280608.&lt;/p&gt;&#xA;&lt;p&gt;98.&#xA;Cockett, A.H.; Smith, K.C.; Bartlett, N. (2013). The Chemistry of the Monatomic Gases: Pergamon Texts in Inorganic Chemistry. Elsevier Science. p. 292. ISBN 9781483157368.&lt;/p&gt;&#xA;&lt;p&gt;99.&#xA;Brock, D.S.; Schrobilgen, G.J. (2011). &amp;quot;Synthesis of the missing oxide of xenon, XeO2, and its implications for earth's missing xenon&amp;quot;. Journal of the American Chemical Society. 133 (16): 6265–9. doi:10.1021/ja110618g. PMID 21341650.&lt;/p&gt;&#xA;&lt;p&gt;Evidence is given in &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GC007779&quot; rel=&quot;nofollow noreferrer&quot;&gt;Crepisson et al (2019)&lt;/a&gt; for xenon (as &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{XeO_2}$&lt;/span&gt;) incorporation into silica at high pressure.  XRD measurements show changes in the lattice consistent with xenon substituting for silicon in the oxide structure.&lt;/p&gt;&#xA;" OwnerUserId="15362" LastEditorUserId="20607" LastEditDate="2020-07-11T13:43:23.767" LastActivityDate="2020-07-11T13:43:23.767" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="16404" PostTypeId="2" ParentId="16395" CreationDate="2019-03-06T09:52:37.433" Score="0" Body="&lt;p&gt;The features probably caused by a volcanic bomb (please see my comment above). Then one may able to learn from the shape of the deformation, the location of the eruption center.&#xA;So, how to determine the kinetic energy amount of the impact, from the dimensions of the deformation features ?&lt;a href=&quot;https://i.stack.imgur.com/lrSy4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lrSy4.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WN90R.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;enter image description here&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hvQL4.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hvQL4.jpg&quot; alt=&quot;new photo and sketches added&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: Though i gave the right answer in another post, I didn't delete this post to let anyone to see the other question in the solving process.&lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="15195" LastEditDate="2019-03-13T20:57:46.773" LastActivityDate="2019-03-13T20:57:46.773" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16405" PostTypeId="1" CreationDate="2019-03-06T15:38:09.950" Score="0" ViewCount="77" Body="&lt;p&gt;&lt;strong&gt;In light&lt;/strong&gt; of the material presented in the link, hopefully not disregarded as a complete mumbo-jumbo, I would like to pose a simple question, as mentioned above in the question - &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;While we are entering Solar Cycle 25: Can a strong solar storm trigger a violent geomagnetic shift&lt;/strong&gt;? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=pBIlzWTTOnU&amp;amp;t=27s&quot; rel=&quot;nofollow noreferrer&quot;&gt;Research&lt;/a&gt;. Thank you for reasoned, precise and specific replies. &lt;/p&gt;&#xA;" OwnerUserId="9620" LastActivityDate="2019-03-06T21:38:32.483" Title="Solar Cycle 25: Can a strong solar storm trigger a violent geomagnetic shift?" Tags="|climate|sun|" AnswerCount="1" CommentCount="5" ClosedDate="2019-03-09T10:41:53.847" ContentLicense="CC BY-SA 4.0" />
  <row Id="16406" PostTypeId="1" CreationDate="2019-03-06T16:27:29.760" Score="5" ViewCount="144" Body="&lt;p&gt;I understand that you could fill multiple books with descriptions of the PETM and the mechanisms that incited the event. I have always wondered what regions of the world were covered in what types of biomes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have read that there was virtually no ice, the tropical latitudes experienced a period of unbelievable wetness, and that many Asian mammals migrated north.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Were the tropics massive rainforests and jungles? Where might we have found desserts during this time? I know that the continents looked much more different than they do today, so if someone could just generalize what parts of the world were covered in what biomes my curiosity would be satisfied.&lt;/p&gt;&#xA;" OwnerUserId="14308" LastEditorUserId="725" LastEditDate="2019-03-06T21:33:57.953" LastActivityDate="2021-08-13T17:56:44.457" Title="Biomes that existed during the Paleocene-Eocene Thermal Max (PETM)" Tags="|climate-change|earth-history|paleoclimatology|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16407" PostTypeId="1" CreationDate="2019-03-06T17:12:39.837" Score="1" ViewCount="1628" Body="&lt;p&gt;The Geologic time scale was completed in the mid to late 1800s. What methods were used to date the various subdivisions?&lt;/p&gt;&#xA;" OwnerUserId="15372" LastActivityDate="2022-06-27T09:39:04.550" Title="What is the basis for the Geologic Time Scale" Tags="|geology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16408" PostTypeId="2" ParentId="16407" CreationDate="2019-03-06T18:08:14.233" Score="4" Body="&lt;p&gt;Here is an answer that matches the wording in this question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nice summary from &lt;a href=&quot;http://hyperphysics.phy-astr.gsu.edu/hbase/Geophys/geotime.html#c2&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://hyperphysics.phy-astr.gsu.edu&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Principles for Relative Dating of Geological Features&lt;/strong&gt;&#xA;From over two hundred years of careful field explorations by geologists, a number of practical principles for determining the relative dates of geologic features have emerged. The assignment of numerical ages to these relative dates had to await the development of radiometric dating.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Law of Superposition**: For sedimentary rocks, each bed is older than the one above it and younger than the one below it.&lt;/li&gt;&#xA;&lt;li&gt;Principle of Original Horizontality. Layers of sediment are generally deposited in a horizontal position. This is useful even if beds of sedimentary rock have been subsequently tilted.&lt;/li&gt;&#xA;&lt;li&gt;Principle of cross-cutting relationships. A fault or intrusion is younger than the rocks affected by it.&lt;/li&gt;&#xA;&lt;li&gt;Inclusions: the rock mass containing the inclusions is older than the rock providing the included material. &lt;/li&gt;&#xA;&lt;li&gt;Unconformities: interruptions of sedimentation with removal of material by erosion and then a resumption of deposition can place rock strata in contact that have a gap of time and material between them.&lt;/li&gt;&#xA;&lt;li&gt;Principle of fossil succession: fossil organisms succeed one another in a definite order. The fossils observed help to identify the time period in which the organism lived.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Does anyone know if there a published book that gives a comprehensive history of geologic time scale (looking for more than summary that is presented in countless text books)?&lt;/p&gt;&#xA;" OwnerUserId="1149" LastActivityDate="2019-03-06T18:08:14.233" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16410" PostTypeId="1" AcceptedAnswerId="16413" CreationDate="2019-03-06T20:29:57.083" Score="1" ViewCount="37" Body="&lt;p&gt;I know that the bulk modulus, K, varies with pressure and temperature for silicate minerals and liquids, but what about the shear modulus? If so, is the change drastic for changes from standard temperature and pressure to mantle conditions?&lt;/p&gt;&#xA;" OwnerUserId="11430" LastEditorUserId="11430" LastEditDate="2021-05-08T21:25:29.213" LastActivityDate="2021-05-08T21:25:29.213" Title="Does the shear modulus of silicate minerals vary significantly with changes in P and T?" Tags="|geophysics|thermodynamics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16411" PostTypeId="2" ParentId="12173" CreationDate="2019-03-06T20:42:28.780" Score="0" Body="&lt;p&gt;There are a couple of ways of going about this, but all require you to know the bulk composition of the system (usually given in wt% oxides). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once you have that you can...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) use a program like MELTS to calculate the phase equilibria.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Do some type of normative mineralogy calculation (see, for example, the CIPW norm). These sorts of heuristics depend on the P,T conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) Bust out your knowledge of thermodynamics and calculate the change in Gibbs Free Energy for the permutations of all the possible phases. I don't recommend doing this - it will take a very long time. &lt;/p&gt;&#xA;" OwnerUserId="11430" LastActivityDate="2019-03-06T20:42:28.780" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16412" PostTypeId="2" ParentId="12173" CreationDate="2019-03-06T21:13:16.267" Score="1" Body="&lt;p&gt;&lt;strong&gt;Perple_X&lt;/strong&gt; (&lt;a href=&quot;http://www.perplex.ethz.ch/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.perplex.ethz.ch/&lt;/a&gt;) is software designed to do exactly that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It has thermodynamic and mineral property databases for phases in interest. This is pretty much automation of method 3 given by the other answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short, the way it works: you input your bulk composition, pressure, and temperature, and it spits out the phase relations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A bit of warning: this software is very poorly documented with many tutorials and guides referring to older version that don't work exactly like the new one. I recommend going on their discussion forum which is very active, and the developer himself is commonly there. He is usually very responsive and can fix bugs pretty much on the spot (time-zone constraints permitting).&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-03-06T21:13:16.267" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16413" PostTypeId="2" ParentId="16410" CreationDate="2019-03-06T21:28:09.133" Score="1" Body="&lt;p&gt;A quick Google Scholar &lt;a href=&quot;https://scholar.google.com/scholar?q=shear%20modulus%20pressure%20olivine&amp;amp;btnG=Search&amp;amp;as_sdt=800000000001&amp;amp;as_sdtp=on&quot; rel=&quot;nofollow noreferrer&quot;&gt;search&lt;/a&gt; for the most studied mantle mineral leads to &lt;a href=&quot;https://doi.org/10.1016/S0012-821X(98)00063-6&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt;, with this in the abstract:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The shear elastic moduli exhibit non-linear pressure dependencies. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So the answer is yes. As for the magnitude and drastic changes, you will have to do some reading.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2019-03-06T21:32:51.383" LastActivityDate="2019-03-06T21:32:51.383" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16414" PostTypeId="2" ParentId="16405" CreationDate="2019-03-06T21:38:32.483" Score="4" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Can a strong solar storm trigger a violent geomagnetic shift?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;h1&gt;No.&lt;/h1&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Geomagnetic shifts (whether violent or not, whatever that means) are caused by changes in the Earth's core.&lt;/p&gt;&#xA;&lt;p&gt;Solar activity only affects the atmosphere and Earth's surface. The shape of Earth's magnetic field can affect how the solar activity interacts with Earth. For example, the intensity and location of auroras, or whether satellite and communication operations will be disrupted or not. The solar activity can slightly change the magnetic field lines, but it will only happen for the duration of the storm itself.&lt;/p&gt;&#xA;&lt;p&gt;Solar activity cannot cause any permanent shift or reversal in Earth's magnetic field.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-03-06T21:38:32.483" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16419" PostTypeId="2" ParentId="8141" CreationDate="2019-03-07T17:08:50.547" Score="0" Body="&lt;p&gt;The previous two answers have pointed to wind shear, which is certainly something that happens.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's also a &lt;em&gt;perceptual&lt;/em&gt; issue, where an object moving one direction in the foreground can cause the &lt;em&gt;illusion&lt;/em&gt; that an isolated background object is moving in the opposite direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thirdly, if you were driving, &lt;em&gt;your own&lt;/em&gt; velocity contributes to perceived motion. If you were driving north, the clouds would appear to be moving south, and &lt;strong&gt;lower clouds would appear to move faster&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fourth: are you sure of your description? &quot;Horse's mane&quot; cloud sounds like &lt;em&gt;cirrus&lt;/em&gt;, which would be much &lt;em&gt;higher&lt;/em&gt; in altitude (&gt;6000m) than stratocumulus (&amp;lt;2000m).&lt;/p&gt;&#xA;" OwnerUserId="13324" LastActivityDate="2019-03-07T17:08:50.547" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16420" PostTypeId="2" ParentId="2246" CreationDate="2019-03-07T17:19:07.357" Score="2" Body="&lt;p&gt;No, the weight of the cloud can't be zero; it has to be &lt;strong&gt;about the same as an equivalent volume of air&lt;/strong&gt;. If a parcel of air-plus-visible-matter is lighter (less dense) than the air around it, it will rise; if it's heavier (more dense), it will fall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clouds are visible because of water droplets or crystals (or smoke particles or whatever) suspended in the air. Air holding suspended liquid or solid matter will be denser than &quot;empty air&quot;, &lt;em&gt;all other things being equal&lt;/em&gt; -- but if the air in the cloud is &lt;em&gt;warmer&lt;/em&gt; or &lt;em&gt;more humid&lt;/em&gt; than surrounding air (since water vapor is less dense than air), it's easy to achieve more or less neutral buoyancy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, yes, clouds are big and heavy -- but they easily float in the atmosphere, which is even bigger and heavier!&lt;/p&gt;&#xA;" OwnerUserId="13324" LastEditorUserId="13324" LastEditDate="2019-03-07T17:31:21.763" LastActivityDate="2019-03-07T17:31:21.763" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16422" PostTypeId="1" CreationDate="2019-03-08T10:07:34.453" Score="1" ViewCount="49" Body="&lt;p&gt;For drought monitoring related to vegetation, I need to calculate Standardized Percipitation INdex for a given area. Where can I find the most real-time percipitation data to do this? The best I've found is CHIRPS data, which has a latency of one month. Is there any freely available data that is more up-to-date?&lt;/p&gt;&#xA;" OwnerUserId="15388" LastActivityDate="2020-01-20T09:02:15.260" Title="What is the most real-time method of determining SPI?" Tags="|remote-sensing|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16423" PostTypeId="1" CreationDate="2019-03-08T10:46:14.637" Score="2" ViewCount="372" Body="&lt;p&gt;The seas in Indonesia or Sunda Shelf or Southeast Asia separates the Indian Ocean and Pacific Ocean. The seas in Indonesia itself are broken into many parts due to presence of islands such as Sunda islands, Philippines etc. Examples include Java Sea, Celebes Sea, Banda Sea, Flores Sea etc. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a collective term to name the seas of Indonesia as a whole region??? &lt;/p&gt;&#xA;" OwnerUserId="15390" LastActivityDate="2019-04-01T12:27:15.647" Title="What is the collective name for the seas of Indonesia?" Tags="|oceanography|geography|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16424" PostTypeId="2" ParentId="16395" CreationDate="2019-03-08T12:34:34.280" Score="0" Body="&lt;p&gt;The radial pattern of the fracture is related to a blast (probably a dynamite) not an impact. The upper part of the rock had blown out by an internal force. So the surface seen on the photographs is not an impacted surface. It is the surface of the remainder part of the original rock. In the impact crater case you might see extensionally origined tangential fractures parallel to the impact crater not the radial cracks as seen on this case.&#xA;Here is an link showing a similar deformation pattern origined by a blast.&#xA;&lt;a href=&quot;http://www.uoguelph.ca/geology/geol2250/glossary/HTML%20files/shattercone.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.uoguelph.ca/geology/geol2250/glossary/HTML%20files/shattercone.html&lt;/a&gt;&#xA;Who are interested in impact craters may want to visit the link below.&#xA;&lt;a href=&quot;http://www.impact-structures.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.impact-structures.com/&lt;/a&gt;&#xA;Thanks for your replies and interests.&lt;/p&gt;&#xA;" OwnerUserId="15195" LastActivityDate="2019-03-08T12:34:34.280" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16426" PostTypeId="2" ParentId="16423" CreationDate="2019-03-08T14:59:42.177" Score="3" Body="&lt;p&gt;I've always known it as the &lt;em&gt;Maritime Continent&lt;/em&gt;, as in,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Neale and Slingo (2003) &lt;a href=&quot;https://doi.org/10.1175/1520-0442(2003)016%3C0834:TMCAIR%3E2.0.CO;2&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Maritime Continent and Its Role in the Global Climate: A GCM Study&lt;/a&gt;, J. Clim, doi:10.1175/1520-0442(2003)016%3C0834:TMCAIR%3E2.0.CO;2&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But that has an atmospheric perspective; it refers to the ocean and the land, because they're both important for the meteorology of the region.  There may be another name for just the watery bits in between the land.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2019-03-08T14:59:42.177" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16427" PostTypeId="1" AcceptedAnswerId="16429" CreationDate="2019-03-09T00:06:30.700" Score="2" ViewCount="43" Body="&lt;p&gt;Does the majorite garnet &lt;span class=&quot;math-container&quot;&gt;$\ce{Mg3(FeSi)Si3O12}$&lt;/span&gt; have a name?&lt;/p&gt;&#xA;" OwnerUserId="11430" LastActivityDate="2019-08-10T00:38:22.513" Title="Name of majorite endmember $\ce{Mg3(FeSi)Si3O12}$" Tags="|mineralogy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16429" PostTypeId="2" ParentId="16427" CreationDate="2019-03-09T03:17:36.327" Score="3" Body="&lt;p&gt;Yes, it's called (unsuprisingly) &lt;strong&gt;majorite&lt;/strong&gt;.&#xA;This is an IMA-approved name, first described from a meteorite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More information: &lt;a href=&quot;https://www.mindat.org/min-2546.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.mindat.org/min-2546.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2019-08-10T00:38:22.513" LastActivityDate="2019-08-10T00:38:22.513" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16431" PostTypeId="1" AcceptedAnswerId="16464" CreationDate="2019-02-17T20:52:12.027" Score="2" ViewCount="184" Body="&lt;p&gt;Why is convective precipitation associated with heavy rains? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As per wikipedia's page on &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_convection&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atmospheric Convection&lt;/a&gt;: &quot;Moist convection leads to thunderstorm development, which is often responsible for severe weather throughout the world&quot;.&lt;/p&gt;&#xA;" OwnerUserId="15303" OwnerDisplayName="Ken Kutcel" LastEditorDisplayName="user1066" LastEditDate="2019-03-09T17:07:09.647" LastActivityDate="2019-03-16T04:13:27.890" Title="Why is convective precipitation associated with heavy rains?" Tags="|meteorology|cloud-microphysics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16434" PostTypeId="1" AcceptedAnswerId="16453" CreationDate="2019-02-11T15:06:13.263" Score="2" ViewCount="426" Body="&lt;p&gt;Why does temperature increase as height increases in the stratosphere (15 km - 60 km above earth), when the ozone molecules are most concentrated at about 25 km?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/KS04L.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KS04L.png&quot; alt=&quot;ozone concentration through stratosphere&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15303" OwnerDisplayName="Ken Kutcel" LastEditorDisplayName="user1066" LastEditDate="2019-03-10T03:17:41.857" LastActivityDate="2019-03-12T23:27:59.950" Title="Stratosphere height vs. Temperature based on ozone concentration" Tags="|temperature|atmospheric-chemistry|ozone|stratosphere|" AnswerCount="1" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16438" PostTypeId="1" AcceptedAnswerId="16530" CreationDate="2019-03-11T00:46:01.537" Score="3" ViewCount="113" Body="&lt;p&gt;Is it possible that, one day in the distant future, it might be true that continental drift would stabilize? For the sake of discussion, we could suppose &quot;stability&quot; would mean less than a meter of movement within a thousand-year span relative to surrounding continents, across all continents (or something along those lines - I'm also curious if there's another definition of &quot;stability&quot; that would be more meaningful here).&lt;/p&gt;&#xA;" OwnerUserId="15410" LastActivityDate="2019-03-20T18:27:47.557" Title="Might continental drift ever stabilize?" Tags="|plate-tectonics|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16439" PostTypeId="1" AcceptedAnswerId="16442" CreationDate="2019-03-11T01:58:25.370" Score="4" ViewCount="2137" Body="&lt;p&gt;Known that it is found in sand, silt and clay but is it found in all soils?&lt;/p&gt;&#xA;" OwnerUserId="15103" LastEditorUserId="725" LastEditDate="2019-03-11T09:10:02.530" LastActivityDate="2021-02-07T14:15:29.667" Title="Is silicon dioxide (silica) found in all types of soil on the planet?" Tags="|soil|soil-science|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16442" PostTypeId="2" ParentId="16439" CreationDate="2019-03-11T09:26:18.830" Score="9" Body="&lt;p&gt;&lt;strong&gt;tl;dr&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Silica is everywhere, in everything. The amounts can be close to 100% in quartz sand, or less than 1% in things like peat or limestones (and derived soils). Finding completely pure soils (let's say less than 0.1%) is wishful thinking.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Silicon dioxide (or silica, or silicon oxide, it's all the same thing) can exist in two &quot;forms&quot;:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;As the compound, most commonly known as quartz, but also all kinds of other materials such as chert, agate, jasper, opal, etc.&lt;/li&gt;&#xA;&lt;li&gt;As the chemical component in other materials (think oxygen in water). Most of the hard and brittle solid materials you know have silica as a chemical component in them. This includes most rocks, clay minerals, concrete, bricks, ceramics, etc.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Silica the compound (as quartz and others) is one of the most abundant materials on the surface. Sand (the white-yellow stuff) is commonly 99% quartz. Silt and clay are actually definitions of grain size, not chemical composition. Most soils that are silt or clay size also have abundant quartz in it. Quartz is a component of dust. This stuff gets everywhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For soils that don't have quartz proper in them, most will have silica as a chemical component. Clay minerals, pyroxenes, amphiboles, micas, feldspars, and all silicate minerals (which are the most common rock forming minerals on Earth).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is easier to talk about the rocks and soils that &lt;em&gt;don't&lt;/em&gt; have any silica in them.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Peat and other organic soils (coal?). These form by decay of plant material, and should not have any silica in them. However, since silica is a component of dust, and dust accumulates when these soils form, there will be some amount of silica. The amount can vary from a few percent to as little as a tenth of a percent, but it will be there.&lt;/li&gt;&#xA;&lt;li&gt;Evaporites. Things like salt, gypsum, etc. These are chemically precipitated rocks which should not have silica. Then again, dust. There will be some amount.&lt;/li&gt;&#xA;&lt;li&gt;Carbonates. Limestone is calcium carbonate. Limestones are rarely pure though, and the most common contaminant is - you guessed it - silica. Because of dust. Or just silicate sediments floating in the sea when the limestones form. &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-03-11T09:26:18.830" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16444" PostTypeId="1" CreationDate="2019-03-11T14:51:11.863" Score="1" ViewCount="37" Body="&lt;p&gt;Along the coast of the Levant (maybe also in other places), there are some very distinct discontinuities such as these. It may be nothing at all, but they stood out to me. Now I was wondering if there was a specific reason for the these specific discontinuities to arise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The one in the picture is at Beirut, but also slight to the south there are several smaller discontinuities in the coast lines. They all seem to be small pieces of north facing coast line. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some I noticed where at Beirut, Saadiyat, between Jiyeh and Jadra, Rmayleh, Iskandarounah, Haifa, Tripoli (lebanon), Ras al Basit, Om al-toyour, Burj Islam, 1 at Jableh and 1 just north of Jableh, Hamat and Hraiche.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am aware not all of these are on the same scale and there are many more. Especially smaller ones, which I did not list. But they do all seem to have a similar shape, leaving me to wonder whether they could have a similar origin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/q1E5U.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/q1E5U.png&quot; alt=&quot;Distinct discontinuity along the coast of the levant.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15413" LastEditorUserId="15413" LastEditDate="2019-03-11T15:00:48.107" LastActivityDate="2019-03-11T15:00:48.107" Title="What causes these shapes in the coast of the Levant?" Tags="|geomorphology|coastal|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16445" PostTypeId="1" CreationDate="2019-03-11T17:24:09.750" Score="1" ViewCount="15" Body="&lt;p&gt;It is notoriously difficult to determine the texture of soil containing allophane and immogolite. According to the literature this is because the clay fraction &quot;behaves as a gel&quot;, i.e. it's not possible to disperse the particles from each other. But why? What actually happens? Somebody who knows, or who has a reference to where it is explained? &lt;/p&gt;&#xA;" OwnerUserId="15414" LastActivityDate="2019-03-11T17:24:09.750" Title="Why do allophane soils behave as gels?" Tags="|minerals|soil-science|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16447" PostTypeId="1" AcceptedAnswerId="16450" CreationDate="2019-03-11T20:05:08.667" Score="1" ViewCount="83" Body="&lt;p&gt;Love-waves cannot exist in a half-space. Layering must be present and there also must be accompanied impedance contrasts associated with the layering.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because layering naturally induces seismic dispersion (in certain frequency ranges) and layering must be present for Love-wave generation, does that - as a corollary - indicate that Love-waves are &lt;em&gt;naturally&lt;/em&gt; and always dispersive?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that the motivation for this question primarily comes from the idea that Rayleigh-waves - which &lt;em&gt;can&lt;/em&gt; exist in a half-space - are &lt;strong&gt;not&lt;/strong&gt; dispersive when layering is not present.&lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2019-03-12T13:26:54.353" Title="Love-Wave Propagation" Tags="|geophysics|seismology|seismic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16450" PostTypeId="2" ParentId="16447" CreationDate="2019-03-12T13:26:54.353" Score="2" Body="&lt;p&gt;Your assertion is correct! See e.g. Stein &amp;amp; Wysession &lt;em&gt;An Introduction to Seismology, Earthquakes, and Earth Structure&lt;/em&gt; (2003) p. 90 ,section 2.7.3: Love waves in a layer over a halfspace (&lt;a href=&quot;https://books.google.ch/books?id=-z80yrwFsqoC&amp;amp;lpg=PP1&amp;amp;hl=de&amp;amp;pg=PA90&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://books.google.ch/books?id=-z80yrwFsqoC&amp;amp;lpg=PP1&amp;amp;hl=de&amp;amp;pg=PA90&lt;/a&gt;). In particular, for any particular frequency/period, Love waves can only have certain horizontal apparent velocities/wavenumbers. Hence, different frequencies have different apparent velocities, which is what we refer to as dispersion. See for example also the figure 2.8-2 from the book, &lt;a href=&quot;https://books.google.ch/books?id=-z80yrwFsqoC&amp;amp;lpg=PP1&amp;amp;hl=de&amp;amp;pg=PA96&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://books.google.ch/books?id=-z80yrwFsqoC&amp;amp;lpg=PP1&amp;amp;hl=de&amp;amp;pg=PA96&lt;/a&gt;, which shows the dispersion curve for a layer over a halfspace.&lt;/p&gt;&#xA;" OwnerUserId="12155" LastActivityDate="2019-03-12T13:26:54.353" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16451" PostTypeId="2" ParentId="15012" CreationDate="2019-03-12T18:32:26.567" Score="2" Body="&lt;p&gt;I found out today that this strange &quot;fossil rock&quot; is actually a sea biscuit (common name) in the class echinoidea. Sand dollars are flat, but the sea biscuits are &quot;puffy&quot;. I found this out in my zoology class! &lt;/p&gt;&#xA;" OwnerUserId="13762" LastActivityDate="2019-03-12T18:32:26.567" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16453" PostTypeId="2" ParentId="16434" CreationDate="2019-03-12T23:27:59.950" Score="3" Body="&lt;p&gt;There are two main points to make here.&lt;/p&gt;&#xA;&lt;p&gt;The first point is that UV radiation is entering the stratosphere from above (ignoring angular dependencies and scattering), so is preferentially absorbed by ozone higher in the stratosphere.  This is a form of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Beer%E2%80%93Lambert_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Beer-Lambert law&lt;/a&gt;, which leads to greater absorption higher in the stratosphere.&lt;/p&gt;&#xA;&lt;p&gt;The second point is that the Dobson Units used in your plot standardize for (partial) pressure and temperature differences between different heights in the stratosphere, so that you can compare the mass or number density of ozone at different levels.  But it doesn't tell you how much ozone there is relative to all the other gases making up the air at a particular height.  A common way to look at this is the &lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Mixing_ratio&quot; rel=&quot;nofollow noreferrer&quot;&gt;mole mixing ratio&lt;/a&gt;&lt;/em&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LKtZa.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LKtZa.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;A height–latitude cross section of annual average ozone mixing ratio (ppmv) from the climatology.&lt;/p&gt;&#xA;&lt;p&gt;Source: McPeters et al (2005), &lt;a href=&quot;https://doi.org/10.1029/2005JD006823&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ozone climatological profiles for satellite retrieval algorithms&lt;/a&gt;, GRL.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;While the ozone concentration peaks around 20 km, the mixing ratio peaks around 30 to 40 km and doesn’t decline so abruptly with height.  Where the mixing ratio is greater, absorption of a particular amount of UV radiation can have a greater effect on the overall air temperature at that height.&lt;/p&gt;&#xA;&lt;p&gt;The net effect of these two properties is that heating of the stratosphere by UV absorption (see plot below) peaks in the upper stratosphere around 50 km.  This is why the greatest temperatures are found in the upper stratosphere.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0AM58.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0AM58.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Heating from absorption of UV radiation (K/day)&lt;/p&gt;&#xA;&lt;p&gt;Source: Haigh (1984) &lt;a href=&quot;https://doi.org/10.1002/qj.49711046312&quot; rel=&quot;nofollow noreferrer&quot;&gt;Radiative heating in the lower stratosphere and the distribution of ozone in a two‐dimensional model&lt;/a&gt;, QJRMS.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="106" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-03-12T23:27:59.950" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16457" PostTypeId="1" CreationDate="2019-03-13T05:11:23.970" Score="4" ViewCount="233" Body="&lt;p&gt;55 million years ago, the world was literally a jungle.  With such high temperatures, rainfall and humidity, life could proliferate.  But 49 million years ago, something drastic happened: The &lt;a href=&quot;https://en.wikipedia.org/wiki/Azolla_event&quot; rel=&quot;nofollow noreferrer&quot;&gt;Azolla Event&lt;/a&gt;, where ice was forming at the poles.  The culprit?  A kind of plant called &lt;em&gt;Azolla&lt;/em&gt;.  Within 800,000 years, photosynthesis and carbon sequestration from those plants reduced the atmospheric quantity of carbon dioxide &lt;a href=&quot;https://www.nature.com/articles/35021000&quot; rel=&quot;nofollow noreferrer&quot;&gt;from 3500 parts per million to 650&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aGu0q.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aGu0q.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[figure from &lt;a href=&quot;https://www.nature.com/articles/35021000&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atmospheric carbon dioxide concentrations over the past 60 million years] &#xA;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the real question here is--&lt;strong&gt;did the cooling caused by the Azolla Event create a major extinction event of plant and animal species?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="4985" LastEditorUserId="4985" LastEditDate="2019-03-14T18:21:02.613" LastActivityDate="2019-03-14T18:21:02.613" Title="Did the Azolla Event 49 Million Years Ago Result in an Extinction Event?" Tags="|paleoclimatology|mass-extinction|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="16459" PostTypeId="1" CreationDate="2019-03-13T12:50:20.743" Score="2" ViewCount="128" Body="&lt;p&gt;I read somewhere that the reason Venus has a runaway greenhouse effect and Earth doesn't is because Venus failed to develop tectonic plates and instead formed a full tectonic plate enveloping the entire planet. And as such, Venus cannot scrub &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO}_2$&lt;/span&gt; from its atmosphere by burying the weathered rock back into the mantle while Earth can, which eventually caused a positive feedback loop of high temperature softening plate preventing fracture which prevents burying of &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO}_2$&lt;/span&gt;, which puts more &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO}_2$&lt;/span&gt; in the atmosphere, which raises the temperature even more. Regardless of the truthfulness of this theory, is the weathering of rock a primary mechanism of &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO}_2$&lt;/span&gt; scrubbing on red-hot primordial Earth long before life occurred?&lt;/p&gt;&#xA;" OwnerUserId="15432" LastActivityDate="2020-11-01T20:04:30.377" Title="Is weathering of rock a primary means of $\text{CO}_2$ scrubbing on primordial Earth?" Tags="|geochemistry|atmospheric-chemistry|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16460" PostTypeId="2" ParentId="15653" CreationDate="2019-03-13T22:25:22.547" Score="8" Body="&lt;p&gt;As @gerrit commented, a precise calculation would need to incorporate a litospheric model to account for isostatic &lt;a href=&quot;https://en.wikipedia.org/wiki/Post-glacial_rebound&quot; rel=&quot;noreferrer&quot;&gt;post-glacial rebound&lt;/a&gt;. But the &quot;blurry approximation&quot; you want, can be obtained based only on topographic data. This approximation would be reasonably accurate if the melting of the ice happens quickly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For this, we need topographic data of the current surface, and of the bedrock topography. That's the bare ground below the ice. The only source of such data at a global scale (at least that I'm aware of) is &lt;a href=&quot;https://www.ngdc.noaa.gov/mgg/global/global.html&quot; rel=&quot;noreferrer&quot;&gt;ETOPO1&lt;/a&gt;, at a resolution of 1 arc-minute (roughly 1.8 km).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A visualization of current surface data from ETOPO1, using an equal-area projection (Eckert IV) and setting the sea level at 0 m looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nPFXt.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nPFXt.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And if we measure sea and land areas, it says that &lt;strong&gt;currently, a 70.97% of the global surface corresponds to oceans&lt;/strong&gt;, pretty consistent with the figure you have. Be aware that this simple approach does not consider lakes or rivers, only oceans. It would also misinterpret below sea level dry land as ocean. However, all those factors are arguably minor contributions at a global scale.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, if we use the bedrock version of ETOPO1, and set the sea level at &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/B9780444635242000051&quot; rel=&quot;noreferrer&quot;&gt;66.5 m, consistent with the best estimates of water stored in land ice&lt;/a&gt;. The globe would look like this&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MSFPJ.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MSFPJ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this case, &lt;strong&gt;if all the ice melts, the fraction of the Earth's surface covered by water would be 75.18%&lt;/strong&gt;. Equivalent to an increase of 4.21% relative to the current value.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-03-16T17:23:11.173" LastActivityDate="2019-03-16T17:23:11.173" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16462" PostTypeId="2" ParentId="10761" CreationDate="2019-03-14T03:55:10.287" Score="2" Body="&lt;p&gt;According to &lt;a href=&quot;https://serc.carleton.edu/integrate/teaching_materials/earth_modeling/student_materials/unit5_article1.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;Ice Sheet Modeling&quot;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;ice behaves as a deformable plastic material, which means that there&#xA;  is a critical shear stress, below which no strain (deformation or&#xA;  flow) will occur ... If the slope is too low, the basal shear stress&#xA;  will not match the critical shear stress, ... but as snow piles up,&#xA;  ... flow will begin. ... The result of this is that a glacier has an&#xA;  equilibrium profile&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A simplified model based on this theory results in the height growing approximately as the square root of the distance from the edge.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YE8be.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YE8be.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Snow falling on the surface does not stay on the surface, but takes a deeper journey through the ice sheet as it is buried by subsequent snow and is compressed into solid ice. Snow falling in the deepest interior parts of Antarctica can take over 100,000 years to reach the ocean.&lt;br&gt;&#xA;  &lt;a href=&quot;https://lima.nasa.gov/antarctica/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA&lt;/a&gt;&#xA;  &lt;a href=&quot;https://i.stack.imgur.com/PbgqH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PbgqH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-03-14T03:55:10.287" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16463" PostTypeId="2" ParentId="16423" CreationDate="2019-03-14T07:56:45.317" Score="3" Body="&lt;p&gt;There is no single term for all of the seas of Indonesia but there are the main seas that make up the archipelago that are, The Karimata Strait, The Java sea, the Arafura Sea, The straits of Malacca, Karimata and Sunda, the Celebes sea, the Sulu sea etc. There is a collective name for the archipelago though, the Nusantara archipelago (excluding the Phillipines and western Malaysia)&#xA;&lt;a href=&quot;https://en.m.wikipedia.org/wiki/Wallacea#/media/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.m.wikipedia.org/wiki/Wallacea#/media/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15429" LastEditorUserId="15429" LastEditDate="2019-04-01T12:27:15.647" LastActivityDate="2019-04-01T12:27:15.647" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16464" PostTypeId="2" ParentId="16431" CreationDate="2019-03-14T12:51:01.010" Score="3" Body="&lt;p&gt;Before we go any further it would be helpful to review this Q/A-&lt;a href=&quot;https://earthscience.stackexchange.com/questions/5380/are-clouds-a-gas-liquid-and-or-solid&quot;&gt;Are clouds a gas, liquid, and/or solid?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The key to understanding this question is to realize that it is missing a comparison. Does convective precipitation produce heavier rains in comparison to some other form of precipitation ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When we look at the different types of precipitation and the respective scales involved hopefully we can see why convective rains produce heavier rainfall. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So there are two forms of precipitation - &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Convective_precipitation&quot; rel=&quot;nofollow noreferrer&quot;&gt;convective&lt;/a&gt; and &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Stratiform_precipitation_area&quot; rel=&quot;nofollow noreferrer&quot;&gt;stratiform&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am going to provide a definition of both types of precipitation based on the magnitude of the mean vertical velocity of an atmospheric volume. So the mean vertical velocity(obtained from observations) is the average &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Vertical_velocity&quot; rel=&quot;nofollow noreferrer&quot;&gt;vertical velocity&lt;/a&gt; over the atmospheric volume being studied(in this case the cloud(s) in question). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So stratiform precipitation is defined as &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$ w &amp;lt;&amp;lt; V_{ice,typical} $&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$w &amp;gt; 0$&lt;/span&gt;.  where w is the mean vertical velocity and &lt;span class=&quot;math-container&quot;&gt;$V_{ice,typical}$&lt;/span&gt; is the terminal fall velocity of ice crystals and snow(typically in the range  1-3 m &lt;span class=&quot;math-container&quot;&gt;$s^{-1}$&lt;/span&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Convection precipitation is defined as &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$ w \approx V_{ice,typical} $&lt;/span&gt; and w is in the range  1-10 m &lt;span class=&quot;math-container&quot;&gt;$s^{-1}$&lt;/span&gt; and sometimes exceeds the value of &lt;span class=&quot;math-container&quot;&gt;$V_{ice,typical}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These definitions are due to Henry Houghton as shown from the reference - &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/1520-0450%281968%29007%3C0851%3AOPMATA%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;On Precipitation Mechanisms And Their Artificial Modification&lt;/a&gt;. Also stratiform precipitation occurs mostly from nimbostratus clouds and convective precipitation occurs from cumulonimbus clouds.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now let us list the different types of &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_instability&quot; rel=&quot;nofollow noreferrer&quot;&gt;instability in the atmosphere&lt;/a&gt; and the scales at which they evolve(any cloud has to form due to an instability in the atmosphere) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Conditional_instability&quot; rel=&quot;nofollow noreferrer&quot;&gt;Conditional instability&lt;/a&gt;/&lt;a href=&quot;http://glossary.ametsoc.org/wiki/Convective_instability&quot; rel=&quot;nofollow noreferrer&quot;&gt;Convective instability&lt;/a&gt; - (usually less than 10 km horizontally) and time scale - few minutes&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Symmetric_instability&quot; rel=&quot;nofollow noreferrer&quot;&gt;Symmetric instability&lt;/a&gt; - ( 200 kms horizontally) and time scale - few hours&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Baroclinic_instability&quot; rel=&quot;nofollow noreferrer&quot;&gt;Baroclinic instability&lt;/a&gt; ( less than 2000 kms horizontally) and time scale - maximum 2-3 days. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now let us match the speed of the vertical motions in the atmosphere with the scales at which a particular instability evolves. I am going to exclude symmetric instability  from this discussion. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Frontal systems(baroclinic instability), systems affected by topographic lifting and large scale horizontal convergence produce stratiform precipitation and continuous rain. In this case growth  occurs by deposition of vapor particles and aggregation of ice particles. Because of the slow updrafts we typically see continuous rainfall spread over a large distance and slowly varying over time. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Localized rain associated with either conditional instability or convective origin produce updrafts of several meters per second. There is not enough time for full growth of precipitation particles. Initial growth occurs just above the cloud base &#xA;and since the time for growth is very short and rain drops grow mainly by &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Accretion&quot; rel=&quot;nofollow noreferrer&quot;&gt;accretion of rain drops&lt;/a&gt;. Heavy rainfall realized over a short period is balanced by the smaller horizontal scale of the event. When convective rainfall is observed over a large horizontal area usually it is balanced by areas that have a) either no rain b) areas having stratiform precipitation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/0123742668&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cloud Dynamics by Robert Houze&lt;/a&gt;, Chapter 6&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-03-16T04:13:27.890" LastActivityDate="2019-03-16T04:13:27.890" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16466" PostTypeId="1" AcceptedAnswerId="16468" CreationDate="2019-03-14T17:43:20.913" Score="2" ViewCount="268" Body="&lt;p&gt;This question asks &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13831/how-to-tell-if-fog-is-made-out-of-water-droplets-or-ice-crystals&quot;&gt;How to tell if fog is made out of water droplets or ice crystals?&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that ice fog makes a rainbow where fog does not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ice crystals aside: How does the water droplet size determine the characteristics of a rainbow? When is a water droplet too small to make a rainbow?&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="11908" LastEditDate="2019-03-15T21:28:39.303" LastActivityDate="2019-03-15T21:28:39.303" Title="At what point are water droplets too small to make a rainbow?" Tags="|water|light|fluid-dynamics|cloud-microphysics|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16468" PostTypeId="2" ParentId="16466" CreationDate="2019-03-14T21:27:06.930" Score="3" Body="&lt;p&gt;Some time ago I posted &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7480/what-causes-a-rainbow-its-colours-and-its-shape/7482#7482&quot;&gt;this&lt;/a&gt; answer about how rainbows are formed, and the Wikipedia link Trond Hansen posted mentions droplet size relative to the wavelength of light.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a rainbow to form, the droplet size has to be large enough, relative to the color with the longest wavelength of visible light, for it to be refracted before reflecting off the backside of the droplet. Refraction occurs because, as the wavefront encounters the change in density between air and water, it slows down. This implies that a droplet would have to be greater than half the wavelength of red light, which is about 740 nm, or about 370 nm.&lt;sup&gt;1&lt;/sup&gt; Also, the light responsible for producing the rainbow enters the droplet off-center and reflects off of the backside of the droplet off-center, so the droplet's diameter would need to be a bit larger than 740 nm.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Light&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Light&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="2959" LastEditorUserId="2959" LastEditDate="2019-03-15T20:55:19.290" LastActivityDate="2019-03-15T20:55:19.290" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16470" PostTypeId="1" CreationDate="2019-03-14T23:28:13.180" Score="1" ViewCount="120" Body="&lt;p&gt;TL;DR: Without lasers, electricity, or otherwise modern tools, could large transparent gems be sliced (like glass window)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I’m world building.&#xA;On this planet they have caves with enormous gemstone/crystal/pretty mineral structures (think lechuguilla) which they mine and most often tumble for currency.&#xA;It occurred to me that they would use these for windows if they could manage to somehow slice the stuff.&#xA;It could be useful to know, their water-based tech is pretty advanced and certain regions have created small magnet-powered motors.&lt;/p&gt;&#xA;" OwnerUserId="15442" LastActivityDate="2019-03-15T09:18:08.730" Title="Can gemstones be cut into sheets?" Tags="|geology|mineralogy|world-building|" AnswerCount="2" CommentCount="6" ClosedDate="2019-03-15T16:41:58.127" ContentLicense="CC BY-SA 4.0" />
  <row Id="16471" PostTypeId="1" CreationDate="2019-03-14T23:58:11.383" Score="5" ViewCount="2006" Body="&lt;p&gt;The image below is a screenshot of forecasted sky cover in percentage for various parts of Arizona. Is the sky cover percentage the percentage of each pixel that has cloud, or is it the percentage of a circle with a certain radius where a certain pixel is the center? Not sure how to word it more clearly.&lt;a href=&quot;https://i.stack.imgur.com/9CyKt.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9CyKt.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6916" LastActivityDate="2019-03-16T16:30:02.040" Title="How do I interpret this &quot;sky cover&quot; chart?" Tags="|meteorology|weather-forecasting|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16472" PostTypeId="2" ParentId="16471" CreationDate="2019-03-15T00:30:46.537" Score="4" Body="&lt;p&gt;&lt;strong&gt;The &quot;sky cover&quot; represents the percentage of sky obscured by clouds, &lt;em&gt;as would be visible to an observer (or weather instrument) at the Earth's surface&lt;/em&gt;.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most direct reference I could find to this quantity was in &lt;a href=&quot;https://www.jpss.noaa.gov/assets/pdfs/ams/2014/presentations/38_Gerth-SkyCover.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this archived presentation&lt;/a&gt; from the American Meteorological Society's 2014 Annual Meeting: &lt;em&gt;&quot;The United States Federal Meteorological Handbook (FMH) No. 1 defines sky cover as “the amount of the celestial dome hidden by clouds and/or obscurations”.&lt;/em&gt; User @MikeChristianson also identified a direct definition for this exact National Digital Forecast Database (NDFD) product &lt;a href=&quot;https://digital.weather.gov/staticpages/definitions.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, confirming this interpretation: &lt;em&gt;&quot;Sky cover is the expected amount of opaque clouds (in percent) covering the sky valid for the indicated hour.&quot;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is also supporting evidence with some additional detail in the &lt;a href=&quot;https://www.weather.gov/publications/nws_guide&quot; rel=&quot;nofollow noreferrer&quot;&gt;NWS Products and Services Reference Guidebook&lt;/a&gt;, specifically &lt;a href=&quot;https://www.weather.gov/media/publications/nws_guide/Section9.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Section 9, Tables and Abbreviations&lt;/a&gt;: &lt;em&gt;The “sky condition” describes the average percentage of the sky that is covered by opaque clouds (not transparent to light) at a given time&lt;/em&gt;, followed by a tabular description of the percentile sky cover forecast interpolated to the forecast image in question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/a3MtJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/a3MtJ.png&quot; alt=&quot;Table describing sky condition and cloud cover forecast parameters&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Slight differences in terminology aside, both of these descriptions equivalently refer to the portion of sky obscured by clouds. For typical weather forecasts (as in the example in question), either would be interpreted as describing the sky as it would be visible to an observer at a given point on the Earth's surface - the visible &quot;celestial dome&quot;. See also the definition quoted &lt;a href=&quot;https://en.wikipedia.org/wiki/Cloud_cover&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; from the 2nd edition of the American Meteorology Society's glossary, defining cloud cover as &quot;observed from a particular location,&quot; in this case the Earth's surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, as noted in the comments, the definitions are vague enough that the observer could be a person or a weather instrument - naturally, the exact details of what would be visible and quantified depend on the observer, but for a simple use of this forecast parameter, the FMH &amp;amp; NDFD definitions support this interpretation of sky cover.&lt;/p&gt;&#xA;" OwnerUserId="14078" LastEditorUserId="14078" LastEditDate="2019-03-16T16:30:02.040" LastActivityDate="2019-03-16T16:30:02.040" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16474" PostTypeId="2" ParentId="16470" CreationDate="2019-03-15T05:34:38.983" Score="0" Body="&lt;p&gt;Gemstones can be cut like any other stone.  (Of course very hard ones like diamond &amp;amp; sapphire will be difficult to cut.) One technique used by the Romans and others for stones like marble was to use a bronze blade with a flow of abrasive - quartz sand, probably - in water.  Not all that different from a modern diamond blade used to cut stone or tile - the major difference is the electric motor.  You could power it with a water wheel instead.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Amethyst is one example of a semi-precious gemstone that forms fairly large crystals (and things like geodes).  It's a form of SiO2, so fairly hard, yet slabs of it (and many other semi-precious gemstones) can be readily found for sale on Amazon, eBay &amp;amp;c.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2019-03-15T05:34:38.983" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16475" PostTypeId="1" CreationDate="2019-03-15T05:58:23.750" Score="5" ViewCount="165" Body="&lt;p&gt;Temperature Anomaly is the measure used to show that the earth is warming. &lt;a href=&quot;http://ete.cet.edu/gcc/?/globaltemp_anomalies/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The formula for temperature anomaly&lt;/a&gt; involves in the subtraction of average temperature measurement over 30 years considered as a base line temperature . Usually temperature anomaly graphs starts from 1880, was the average taken from 1850 or which 30 years was used in the baseline or average temperature calculation?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;can you suggest places that i can learn about these and get these data?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;even though subtracting the baseline temperature reduces the influence of errors in measurement, still how are these error accounted for in these graphs? even modern thermometer have +/- 0.5 deg error how are these error removed from the dataset? &lt;/p&gt;&#xA;" OwnerUserId="15440" LastEditorDisplayName="user1066" LastEditDate="2019-03-15T11:26:56.673" LastActivityDate="2019-03-15T11:26:56.673" Title="How temperature anomaly are measured" Tags="|atmosphere|climate-change|temperature|measurements|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="16476" PostTypeId="2" ParentId="16470" CreationDate="2019-03-15T09:18:08.730" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;sliced (like glass window)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Window glass is not sliced into sheets. &lt;a href=&quot;https://en.wikipedia.org/wiki/Architectural_glass#Float_glass&quot; rel=&quot;nofollow noreferrer&quot;&gt;It is made as sheets from the beginning.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since you're looking for a naturally occurring mineral that can be made into a glass-like material, look no further than &lt;strong&gt;muscovite&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vFWex.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vFWex.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because your planet has nice and big crystals, it most likely come from &lt;a href=&quot;https://en.wikipedia.org/wiki/Pegmatite&quot; rel=&quot;nofollow noreferrer&quot;&gt;pegmatites&lt;/a&gt;, which is a type of rock that has large crystals and many gemstones we know today come from pegmatites (emerald, tourmaline, topaz, kunzite, etc). Pegmatites also have huge crystals of muscovite as well, in some rare occasions several metres wide. Muscovite can be easily split into sheets that are flexible and mostly transparent. Not the best glass material (because it is not glass after all), but almost as good. Quoting from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Muscovite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; page:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The name muscovite comes from Muscovy-glass, a name given to the mineral in Elizabethan England due to its use in medieval Russia as a cheaper alternative to glass in windows. This usage became widely known in England during the sixteenth century with its first mention appearing in letters by George Turberville, the secretary of England's ambassador to the Russian tsar Ivan the Terrible, in 1568. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://youtu.be/fTsU2h_jy0o&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's a good video showing how this is working.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the inhabitants of your planet can mine the other crystals in the pegmatite for currency or whatever, and use the muscovite as building material.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-03-15T09:18:08.730" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16478" PostTypeId="1" AcceptedAnswerId="16479" CreationDate="2019-03-15T10:05:45.740" Score="3" ViewCount="219" Body="&lt;p&gt;Artist Rosten Wu's Vimeo channel has a video title &lt;a href=&quot;https://vimeo.com/315754123&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bridging Time&lt;/a&gt; and there is discussion about the &lt;a href=&quot;https://en.wikipedia.org/wiki/Keeling_Curve&quot; rel=&quot;nofollow noreferrer&quot;&gt;Keeling Curve&lt;/a&gt; and the site where it all began in Hawaii. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the video there is a shot of a weather observation station (shown below), and I'm assuming this is &lt;a href=&quot;https://en.wikipedia.org/wiki/Mauna_Loa_Observatory&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mauna Loa Observatory&lt;/a&gt; where these accurate and systematic measurements of CO2 began.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the foreground there are several gizmos and I was wondering if someone can identify them. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've included a cropped section, sharpened it a bit, and added annotations A, B, C &lt;em&gt;below&lt;/em&gt; the three types of instruments that caught my eye.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8fVBT.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8fVBT.jpg&quot; alt=&quot;Mauna Loa Observatory Gizmos&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/98qRY.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/98qRY.jpg&quot; alt=&quot;Mauna Loa Observatory Gizmos&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T20:49:30.713" LastActivityDate="2019-08-28T20:49:30.713" Title="What are these Gizmos at Mauna Loa Observatory?" Tags="|meteorology|earth-observation|instrumentation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16479" PostTypeId="2" ParentId="16478" CreationDate="2019-03-15T13:09:08.703" Score="6" Body="&lt;p&gt;I am going to take a guess here because I have not used these instruments in real life but given the content of this &lt;a href=&quot;https://www.youtube.com/watch?v=3jOAlC2dVtA&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mauna Loa Observatory I Exploratorium&lt;/a&gt; video - fast forward the video to 3:43 and see the yankee name on that instrument.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then I did a google search on that and got this link - &lt;a href=&quot;http://www.yesinc.com/products/raduv.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Yankee list of products&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So A is a &lt;a href=&quot;https://en.wikipedia.org/wiki/Pyranometer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pyranometer&lt;/a&gt; and B is a  Ultraviolet Multifilter Rotating Shadowband Radiometer. I am not too sure on C and it probably is a &lt;a href=&quot;https://en.wikipedia.org/wiki/Actinometer&quot; rel=&quot;nofollow noreferrer&quot;&gt;actinometer&lt;/a&gt;. You can take a look of that here - &lt;a href=&quot;https://www.alamy.com/modern-sunshine-recorder-and-pyranometer-type-of-actinometer-used-for-measuring-solar-irradiance-on-a-roof-image218375621.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Actinometer&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The respective data sheets give information on both of those products.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) &lt;a href=&quot;http://www.yesinc.com/products/data/uvb1/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ultraviolet pyranometer&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As this AMS glossary definition mentions a &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Pyranometer&quot; rel=&quot;nofollow noreferrer&quot;&gt;pyranometer&lt;/a&gt; measures both direct solar radiation(radiation that has not been scattered or absorbed) as well as diffuse sky radiation(radiation that is scattered)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Specifically this ultraviolet pyranometer measures both UV-B and UV-A rays. &#xA;&lt;a href=&quot;https://uihc.org/health-topics/what-difference-between-uva-and-uvb-rays&quot; rel=&quot;nofollow noreferrer&quot;&gt;This link&lt;/a&gt; covers the difference btween UV-B and UV-A rays. Specifically UV-A rays penetrate deeper into the skin than UV-B rays. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) &lt;a href=&quot;http://www.yesinc.com/products/data/uvmfr7/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt; Ultraviolet Multi-Filter Rotating Shadowband Radiometer &lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This one measures the diffuse and total global irradiance and computes direct irradiance at four or seven narrow bandwidth wavelengths(hence the term multi filter). One can see real time data for sites across the US  at this site - &lt;a href=&quot;http://uvb.nrel.colostate.edu/UVB/index.jsf&quot; rel=&quot;nofollow noreferrer&quot;&gt;UV-B monitoring&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) Originally I thought C was a actinometer but when I look at this image &lt;a href=&quot;https://www.esrl.noaa.gov/gmd/grad/surfrad/tmtpics/platform1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Downwelling SURFRAD instruments&lt;/a&gt; I am going to say it is a &lt;a href=&quot;https://www.licor.com/env/products/light/quantum.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;LICOR PAR sensor&lt;/a&gt;(PAR is  Photosynthetically active radiation). The reason is because of the instrument inventory provided in this URL - &lt;a href=&quot;https://www.esrl.noaa.gov/gmd/grad/surfrad/tmtpics/&quot; rel=&quot;nofollow noreferrer&quot;&gt;SURFRAD BOULDER CO&lt;/a&gt;. If you notice in the NOAA ESRL image there is an instrument that  has a shape of a long column(in grey and to the right of the black colored instrument that is actually a &lt;a href=&quot;https://www.arm.gov/capabilities/instruments/mfrsr&quot; rel=&quot;nofollow noreferrer&quot;&gt;MFRSR&lt;/a&gt;) that looks very similar to OP's C instrument. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can now guess why that observatory has these set of instruments. It is at an altitude and that is a good place to study effect of &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_irradiance&quot; rel=&quot;nofollow noreferrer&quot;&gt;Solar irradiance&lt;/a&gt;(less pollution)&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-04-22T12:07:23.383" LastActivityDate="2019-04-22T12:07:23.383" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="16480" PostTypeId="1" AcceptedAnswerId="16483" CreationDate="2019-03-15T13:55:13.137" Score="6" ViewCount="208" Body="&lt;p&gt;IERS &lt;a href=&quot;https://datacenter.iers.org/data/latestVersion/13_FINALS.DAILY_IAU2000_V2013_0113.txt&quot; rel=&quot;noreferrer&quot;&gt;Bulletin A&lt;/a&gt; and &lt;a href=&quot;https://datacenter.iers.org/data/latestVersion/207_BULLETIN_B207.txt&quot; rel=&quot;noreferrer&quot;&gt;Bulletin B&lt;/a&gt; contains Earth orientation parameters. These include the time difference between UT1 and UTC and pole position. The values for these parameters are listed once per day, keyed by &quot;MJD&quot; (Modified Julian Date).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The documentation does not say which time scale these MJD values reference. Without qualification, MJD is typically taken to mean some flavor of Universal Time. If that is the case, which flavor of universal time is it: UTC, UT1, or some other flavor? If that's not the case, which is it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm using the data in an interpolative fashion (Lagrange interpolation) to estimate the Earth orientation parameters at arbitrary points in time, so not having the correct time standard will lead to small errors in the interpolated values.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2019-07-16T16:59:24.010" Title="Time standard for IERS Bulletin A" Tags="|geophysics|planetary-science|earth-rotation|earth-observation|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16481" PostTypeId="1" AcceptedAnswerId="16482" CreationDate="2019-03-15T15:30:42.167" Score="5" ViewCount="147" Body="&lt;p&gt;This &lt;a href=&quot;https://earthscience.stackexchange.com/a/16479/6031&quot;&gt;answer&lt;/a&gt; explains that the device labeled &quot;B&quot; in the photo below is a &quot;Ultraviolet Multifilter Rotating Shadowband Radiometer.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is a Rotating Shadowband Radiometer, and how does it work?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8fVBT.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8fVBT.jpg&quot; alt=&quot;Mauna Loa Observatory&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Screenshot from &lt;a href=&quot;https://vimeo.com/315754123&quot; rel=&quot;noreferrer&quot;&gt;https://vimeo.com/315754123&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="24481" LastEditorDisplayName="user12525" LastEditDate="2021-09-28T22:15:36.500" LastActivityDate="2021-09-28T22:15:36.500" Title="What is a Rotating Shadowband Radiometer, and how does it work?" Tags="|measurements|sun|instrumentation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16482" PostTypeId="2" ParentId="16481" CreationDate="2019-03-15T19:07:51.187" Score="7" Body="&lt;p&gt;A rotating band shadow meter will give you the diffuse radiance as well as direct radiance.  When the band is in the lower location the sensor will measure all the radiance from the sun both direct and indirect.  when the band is raised it blocks the direct sun into the sensor giving an indirect radiance measurement.  The total radiance - the indirect radiance will give you direct radiance.  In this case the meter is setup to capture the UV portion of the spectrum.  Multifilter suggests that it can record radiance for bands of UV radiance so it would be tracking radiance on two or more ranges wavelengths.  The model described in &lt;a href=&quot;http://www.yesinc.com/products/data/mfr7/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this lin&lt;/a&gt;k supports six distinct frequencies though none are in the UV band.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The band rotates above the sensor occluding the light from the sun, when the radiance is at its lowest during the band rotating you are, typically, capturing the point where the direct sunlight is being filtered by the band.  When the band is not occluding the sun you would be capturing the highest radiance. The sampling rate would be setup in the datalogger or computer to allow radiance values at specific time intervals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A short video of one in operation can be seen in &lt;a href=&quot;https://twitter.com/AEMET_Izana/status/1110191707818262529&quot; rel=&quot;nofollow noreferrer&quot;&gt;this tweet&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastEditorUserId="6031" LastEditDate="2019-04-13T13:16:40.733" LastActivityDate="2019-04-13T13:16:40.733" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16483" PostTypeId="2" ParentId="16480" CreationDate="2019-03-15T19:08:52.847" Score="3" Body="&lt;p&gt;Short answer: UT1&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Long answer:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Julian_day&quot; rel=&quot;nofollow noreferrer&quot;&gt;Julian Day&lt;/a&gt; (JD) is just a consistent day count since the beginning of the Julian period, that is January 12th 4713 BC. As the numbers tend to be large (today is day 2,458,557.5), in the 80's and motivated by computer memory limitations, the reduced JD was created which is just &lt;span class=&quot;math-container&quot;&gt;$JD-2400000$&lt;/span&gt;. Then, to remove the annoyance that the Julian Day starts at midday instead of midnight, the Modified JD (MDJ) was created, which is just &lt;span class=&quot;math-container&quot;&gt;$JD-2400000.5$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By definition the MJD zeroes at solar noon at the 0° meridian. Therefore, it is not a regular time measure, it is tied to Earth's rotation and accelerates or decelerates depending on minute variations of Earth's rotating speed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can use basically any solar time including all flavors of UT time to define your MJD, but the most precise is UT1.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But UT1 is not a regular measure of time either, and is also affected by variations on Earth rotation speed. The only really regular time standard among the ones you mention is UTC, which is based on atomic clocks. Being regular, the solar noon drift off UTC and doesn't happen at 12:00 h UTC, therefore, &lt;a href=&quot;https://en.wikipedia.org/wiki/Leap_second&quot; rel=&quot;nofollow noreferrer&quot;&gt;leap seconds&lt;/a&gt; are added to keep UTC reasonably close to solar time. But a record of leap seconds is kept so you can use UTC to precisely measure time intervals independently of the variations of Earth's rotation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In that sense UT1 and UTC are not two flavors of the same thing as you suggest, they actually measure two completely differing things. The first measure Earth's rotation and the second measures time. Due to the same reason, MJD cannot or should not really be referenced to UTC (otherwise it would not zero solar noon).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Said this, in those bulletins the MJD conveys exactly the same information than the date. So &quot;2019 1 2&quot; meaning January 2nd 2019, conveys exactly the same information than MDJ 58485, it is just a more machine friendly way to refer to a specific day. And it also removes the need to account for missing calendar days if you work with dates relatively far in the past.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now if you want to know how much time have elapsed between two entries in the table, you need to know how to transform whatever version of solar time they use (UT1 in this case), to a regular time reference like UTC or &lt;a href=&quot;https://en.wikipedia.org/wiki/International_Atomic_Time&quot; rel=&quot;nofollow noreferrer&quot;&gt;TAI&lt;/a&gt;. That's why the &quot;UT1-UTC&quot; value is included. In any case, in doing such calculation you need to take in account any leap seconds added to UTC between the time of the two entries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does that makes sense?&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-03-15T20:16:24.450" LastActivityDate="2019-03-15T20:16:24.450" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="16486" PostTypeId="1" AcceptedAnswerId="16490" CreationDate="2019-03-16T04:23:20.407" Score="5" ViewCount="2787" Body="&lt;p&gt;Even if all the carbon dioxide (which makes up less than 1% of the atmosphere) in the air were sequestered by plants, would the atmosphere not remain about 21% oxygen? Why did the carboniferous period have 35% atmospheric oxygen?&lt;/p&gt;&#xA;" OwnerUserId="15441" LastEditorUserId="11908" LastEditDate="2019-03-17T18:22:15.683" LastActivityDate="2019-03-17T18:22:15.683" Title="Why did the carboniferous period have so much atmospheric oxygen?" Tags="|atmosphere|geophysics|paleoclimatology|carbon-cycle|oxygen|" AnswerCount="2" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="16488" PostTypeId="2" ParentId="16486" CreationDate="2019-03-16T14:53:31.030" Score="8" Body="&lt;p&gt;The Carboniferous was when the growth of woody plants took off. Non-plant life had not yet evolved the ability to consume lignins, the key chemical components that makes woody plants &quot;woody&quot;. Lignins are rather hard to decompose. Despite high volcanic activity, carbon dioxide levels fell by a factor of over four during the Carboniferous, from over sixteen times preindustrial levels at the start of the period to less than four times preindustrial levels at the end of the period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The end result was a gradual increase in oxygen levels and huge deposits of then non-digestible materials that eventually became coal. &lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2019-03-16T20:28:14.447" LastActivityDate="2019-03-16T20:28:14.447" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="16489" PostTypeId="2" ParentId="286" CreationDate="2019-03-16T20:44:00.903" Score="8" Body="&lt;p&gt;Pyroclastic flows can cross water. This doesn't suggest that any pyroclastic deposit can cross water. High energy had needed. For high energy a caldera forming explosion and/or high temperature flow had needed&lt;a href=&quot;https://i.stack.imgur.com/U1gYC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/U1gYC.png&quot; alt=&quot;the fate of submarine flow &quot;&gt;&lt;/a&gt;. Crossing water also doesn't suggests every material in a single flow pass over the water. Gradually the flowing material amount decreases. The distal deposits are silt to sand sized pumicious grains. Note that pumice can flow over water because of its high porous structure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are the notes from the paper* titled &lt;em&gt;Pyroclastic flows and surges over water:an example from the 1883 Krakatau eruption&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;.... Pyroclastic flows and surges that traveled over the sea for distances up to 80 km.......Energetic flows spread out away from the volcano at speeds in excess of 100 km/h and traveled up to 80 km from source. The flows retained temperatures high enough to burn victims on the SW coast of Sumatra..... &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here more details from the same paper;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;15 km from the source flow deposited 1-2 m pyroclastics on Sebesi island.flows were moving with sufficient energy to pass over the 832-m peak of Sebesi island, inferring a maximum velocity of 320 km/h.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;20 km from the source massive and poorly sorted features of the deposits indicate suspension sedimentation from the basal part of a high-particle-concentration flow.  Density assumed  &amp;lt; 1000 kg/m 3,  the maximum particle concentration would be 45%. Temperature 500 C&lt;/p&gt;&#xA;&#xA;&lt;p&gt;40 km from the source temperature fall to 100-200 C. At this distance from Krakatau the deposition of tephra was not significant (several centimeters) implying that the particle concentration had been significantly reduced to perhaps only a few percent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;60 km were apparently more dilute and cooler. few cm in thickness material deposited.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The distal deposits exhibit a decrease in sorting coefficient, median grain size, and thickness with increasing distance from Krakatau&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some notes on mechanism from the same paper&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the flow is at high temperature it will vaporize the underlying water and&#xA;result in (a) expansion of the gas/particle mixture, (b)an increase in the turbulence, and (c) a decrease in friction. All of these effects will enhance the support of particles and thus reduce the amount of deposition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Druitt and Sparks(1984)have proposed that peak magma discharge occurs at the time of caldera formation, as the subsiding volcanic edifice exerts a dynamic pressure on the underlying magma chamber. The increase in magma discharge&#xA;at Krakatau led to a high flux of pyroclastic flows into and over the sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Widespread reports of mud rain closely associated with the 10 a.m. flow is attributed to the formation of a large co-ignimbrite plume laden with moisture from pyroclastic flows and surges which traveled over the sea.&#xA;The transfer of heat from the flows to the sea surface led to the production of steam. As sedimentation reduced the flow's density, a moisture-rich buoyant&#xA;plume lifted off, carrying fine-grained tephra and steam. Secondary phreatic explosions from shallow and proximal submarine pyroclastic flows may also have&#xA;contributed tephra and steam to the plume,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reference *Carey, S., Sigurdsson, H., Mandeville, C. et al. Bull Volcanol (1996) 57: 493. &lt;a href=&quot;https://doi.org/10.1007/BF00304435&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1007/BF00304435&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: What had happened to the part of the pyroclastics which had entered water?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Answer and image have taken from the &quot;Sedimentology of the Krakatau 1883 submarine pyroclastic deposits&quot; paper* &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The submarine facies;&#xA;The most common submarine facies properties: it is a massive, poorly sorted mix- ture of pumice and lithic lapilli-to-blocks set in a fine silty to sandy ash matrix. Which is the same facies with the subaerial deposits which lies on the remnant cliffs of the Krakatau island.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;The submarine deposition related events: deposition of the submarine massive facies resulted from sinking of a high concentration, deflated basal component of subaerial pyroclastic flows which entered the sea either directly at the shoreline (e.g., west coast of Sertung), or several kilometers from source.&#xA;Evidence which suggests minimal pyroclastic flow/seawater interaction is the lack of tractional sedimentary structures, retention of the fine ash fraction, and lack of hydraulic fractionation of components. Evidence for high tempera- ture emplacement (475-550 C of the massive facies consists of well-grouped thermoremanent magnetizations of both lithic and juvenile components as small as 0.5 cm in maximum diameter. The deposits are therefore interpreted as true suba- queous pyroclastic flow deposits. A less common, distinctly laminated syneruptive facies is well sorted, fine grained, and vitric enriched. In contrast to the massive facies, the laminated facies exhibits small-scale tractional sedimentary structures such as 1-mm-thick planar laminae and 1-cm-scale low-angle cross-stratification. Deposition of the laminated facies was most likely from low-concentration turbulent flows shed from the boundary layer between sinking high concentration pyroclastic flows and seawater, or a steam-rich fluid phase. In this case turbulent mixing produced low-con- centration flows in which components were fraction- ated according to their settling velocities. The facies association observed in the syneruptive subaqueous pyroclastic deposits is similar to that re- ported from an ancient sequence within the lower Mio- cene Tecuya formation (Cole and DeCelles 1991) where flow integrity appears to have been maintained in the transition from subaerial to submarine environ- ment. This association of laminated and massive depos- its can be expected where high concentration flows are discharged into water.&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;*Mandeville, C. W., Carey, S., &amp;amp; Sigurdsson, H. (1996). Sedimentology of the Krakatau 1883 submarine pyroclastic deposits. Bulletin of Volcanology, 57(7), 512-529.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: In a research* it is suggested that a turbidite current can flow over barriers, if the thickness of the flow exceeds %65 of the barrier. One may interpret this that, after a pyroclastic current dives to shallow water it may come back to the surface again.&lt;a href=&quot;https://i.stack.imgur.com/YKfih.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YKfih.png&quot; alt=&quot;from Kokelaar(2007)&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Muck, M.T. and Underwood, M.B., 1990. Upslope flow of turbidity currents: A comparison among field observations, theory, and laboratory models. Geology, 18(1), pp.54-57.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;One more edit:&#xA;There is a downloadable paper which based on laboratory experiments. It explains the mechanism of how a pyroclastic flow can cross water. After looking this paper one may see that the results of the experiments are concordant with the real world incidents such as Krakatoan flow which i have tried to explain. Here is link of the paper. &lt;a href=&quot;https://www.researchgate.net/publication/225813471_Entrance_of_hot_pyroclastic_flows_into_the_sea_Experimental_observations&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/publication/225813471_Entrance_of_hot_pyroclastic_flows_into_the_sea_Experimental_observations&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="15195" LastEditDate="2019-03-18T19:37:47.957" LastActivityDate="2019-03-18T19:37:47.957" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16490" PostTypeId="2" ParentId="16486" CreationDate="2019-03-16T23:14:53.227" Score="6" Body="&lt;p&gt;To complement @DavidHammen answer and address the point &quot;where did so much oxygen come from?&quot; I will elaborate on David's final remark&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The end result was a gradual increase in oxygen levels&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The short answers to &quot;where did so much oxygen come from?&quot; is: mostly from volcanos in the form of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To understand this, we have to consider that the amount of atmospheric &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; is controlled by sources and sinks. At geological time scales the main source is volcanic activity and the main sink is &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonate%E2%80%93silicate_cycle&quot; rel=&quot;noreferrer&quot;&gt;silicate weathering&lt;/a&gt;.&#xA;A key point to consider in this case the that the source is independent of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; concentration while the sink is proportional to &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; concentration (and other factors like temperature or surface of exposed silicate rocks).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, if you have intense photosynthetic activity like the one described by @DavidHammen you can lower atmospheric &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; concentration, therefore reducing the intake by natural silicate weathering sinks, and at the same time increasing the atmospheric oxygen concentration. While this takes place, volcanoes keep putting &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; into the atmosphere and plants keep turning it into oxygen. If you keep this going on for a long enough time, you can rise oxygen levels as high as you want. Although, at some point other feedbacks will kick in to keep the oxygen level at bay. For example, wildfires will be more common and extensive in an oxygen-rich atmosphere, providing a stabilizing feedback that keeps a balance between &lt;span class=&quot;math-container&quot;&gt;$\ce{O2}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Effectively, plants in such scenario would have replaced part of the contribution of the weathering sink of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt;. With the notable difference that the oxygen instead of getting washed to the deep ocean (and eventually subducted), was getting piled into the atmosphere as &lt;span class=&quot;math-container&quot;&gt;$\ce{O2}$&lt;/span&gt;, thus, slowly rising its atmospheric concentration.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-03-16T23:26:23.947" LastActivityDate="2019-03-16T23:26:23.947" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="16491" PostTypeId="1" CreationDate="2019-03-17T01:47:59.753" Score="10" ViewCount="212" Body="&lt;p&gt;Say we will emit a certain amount of greenhouse gas over the next 50 years (e.g. 100 billion tons CO2-eq in total). What would happen if I implement a certain GHG mitigation effort to cut the same amount of GHG (say sequester 20 billion tons CO2-eq) in the early years (e.g. year 0-10) vs in later years (year 40-50)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would imagine that cutting the gas earlier would be better since overall global warming is a cascade of positive feedbacks? A bunch of other similar questions can be asked like cutting the same amount of GHG over first 10 years (but no cutting thereafter) vs spread out the cutting to the entire 50 years. What are some major consideration to look at? Is it generally better to cut GHG as early as possible?&lt;/p&gt;&#xA;" OwnerUserId="3241" LastActivityDate="2019-03-17T02:32:13.147" Title="About the actual radiative impact of greenhouse gas emission over time" Tags="|climate-change|climate-models|greenhouse-gases|radiation-balance|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16492" PostTypeId="2" ParentId="16491" CreationDate="2019-03-17T02:32:13.147" Score="7" Body="&lt;p&gt;There is no doubt that the sooner the mitigation effort happens, the greater will be its impact.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, the impact on year 2100 climate of the sequestration of 20 billion tons &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt;-eq right now, is much bigger than the impact that the same action will have in 30 years from now. Therefore, a mitigation action today is much cheaper than one done in the future but with equal impact on year 2100 climate (assuming no dramatic changes in the sequestration technology).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is due to the long lifetime of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; in the atmosphere, that is usually estimated to be &lt;a href=&quot;https://www.annualreviews.org/doi/10.1146/annurev.earth.031208.100206&quot; rel=&quot;noreferrer&quot;&gt;longer than a few centuries&lt;/a&gt;. Although, some sources place the &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2005JD005888&quot; rel=&quot;noreferrer&quot;&gt;lower limit at around 30 years&lt;/a&gt;, its lifetime is most likely longer than 50 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This means that any &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; that is not captured today (or emitted), will remain in the atmosphere trapping heat and rising Earth's temperature until year 2100 and beyond.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-03-17T02:32:13.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16493" PostTypeId="1" CreationDate="2019-03-17T10:24:50.080" Score="8" ViewCount="83" Body="&lt;p&gt;The answer to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2523/how-long-until-earths-core-solidifies/&quot;&gt;How long until Earth's core solidifies?&lt;/a&gt; question cites an estimation that the Earth (as a planet, not the surface of it) has cooled down by about 250K since it was formed.&lt;/p&gt;&#xA;&lt;p&gt;The question is, just by how much the Earth's effective/average diameter has decreased because of this cooling?&lt;/p&gt;&#xA;&lt;p&gt;Also, considering that the Earth's crust has appeared &amp;quot;almost immediately&amp;quot; -- about a hundred million years -- after the Earth's formation, what has happened to it because of this cooling?&lt;/p&gt;&#xA;&lt;p&gt;There is also the effect of the Earth's mass increase due to its gravitation pulling cosmic dust as well as cosmic bodies falling onto it, which surpass the loss of mass through the atmosphere, thus slightly increasing the weight of crust and its pressure against the mantle.&lt;/p&gt;&#xA;&lt;p&gt;Obviously, the crust is too (relatively) thin and weak to allow emptinesses/cavities/hollows appearing under itself because of the shrinkage of the inner matter, so it was breaking in places thus forming continents that float over the mantle and &amp;quot;falling&amp;quot; downwards a bit instead, right?&lt;/p&gt;&#xA;&lt;p&gt;Or the additional volume because of the cooling did not really change the Earth's effective/average diameter at all since the mantle (and deeper layers) was pushing against the crust with high pressure in the first place so the decrease of volume of the Earth's innards did not happen and it all only ended up decreasing the pressure against the crust, thus decreasing volcanic activity instead of changing the effective/average diameter of the planet?&lt;/p&gt;&#xA;&lt;p&gt;Thanks in advance.&lt;/p&gt;&#xA;&lt;p&gt;(The question was inspired by &lt;a href=&quot;https://en.wikipedia.org/wiki/Dunno_on_the_Moon&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dunno on the Moon&lt;/a&gt; scientific fiction novel, which is obviously unrealistic, but is fun to wonder about hypothetically in terms of real-life physics.)&lt;/p&gt;&#xA;" OwnerUserId="15453" LastEditorUserId="15453" LastEditDate="2022-04-19T15:02:20.280" LastActivityDate="2022-04-19T15:02:20.280" Title="By how much did the Earth's diameter decrease due to cooling, if at all, since it was formed?" Tags="|temperature|core|crust|mantle|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16495" PostTypeId="1" CreationDate="2019-03-17T13:26:47.093" Score="3" ViewCount="57" Body="&lt;p&gt;I have land in India (the tropics), in the hills, on a slope from 6800 feet - 5200 ft altitude (roughly). At that lowest point there's a stream of about 10-15m across. On one side is our land, on the other side, a steep thickly forested slope upwards. Generally my entire land is a very sunny area, high radiation, though not hot like the tropical plains (it rarely crosses 28C even in summer, usually hangs around 20-25C during the day. In Winter, it drops to a minimum of 7C, and hangs around 13-19C during the day).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This stream portion of my land is as yet unexplored and unused. I have rudimentary equipment to measure the microclimate (min-max thermometer, hygrometer), but I don't want to waste a year measuring things if possible.. so are there likely to be any appreciable microclimactic differences one can expect along a stream so small? &lt;/p&gt;&#xA;" OwnerUserId="13104" LastActivityDate="2019-03-17T13:26:47.093" Title="Any appreciable differences in microclimate on the shores of small mountain streams?" Tags="|meteorology|climate|agriculture|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16498" PostTypeId="2" ParentId="12926" CreationDate="2019-03-17T16:48:00.347" Score="1" Body="&lt;p&gt;You have focused on corals (that have a much more lower biomass than for example foraminifera), and you have forgotten what controls carbonate levels at oceans at bigger scale is Henry's Law:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;In chemistry, Henry's law is a gas law that states that the amount of dissolved gas in liquid is proportional to its partial pressure above the liquid . The proportionality factor is called the Henry's law constant&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Henry%27s_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So answering your question what controls acidity on oceans is indeed carbonates, but it is atmospheric &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; levels (and temperature, as Henry's constant is temperature dependent) what determine the concentration of carbonates.&lt;/p&gt;&#xA;&lt;p&gt;The quaternary increase of &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; leads to the generation of new &lt;span class=&quot;math-container&quot;&gt;$H^+$&lt;/span&gt; and thus acidify the ocean, acording to the reaction:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$CO2 (aq) + H2O ⇌ H2CO3 ⇌ HCO3− + H+ ⇌ CO32− + 2 H+.$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorUserId="-1" LastEditorDisplayName="user12525" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-03-17T17:29:19.693" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16501" PostTypeId="1" CreationDate="2019-03-18T04:40:26.273" Score="8" ViewCount="129" Body="&lt;p&gt;I was watching a segment about tidal power generation on a &lt;a href=&quot;https://youtu.be/mEKTLRUFdO0?t=703&quot; rel=&quot;noreferrer&quot;&gt;PBS NewsHour broadcast&lt;/a&gt;. I've set the time code at about &lt;code&gt;11:45&lt;/code&gt; to capture a little background. This bit starts at 12:36:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;As the tide ebs and flows, the turbines spin between seven and fifteen times a minute, generating power similar to a wind turbine. Cables cary the energy back to shore; first underwater, then underground, where it’s then fed into the national grid.&lt;/p&gt;&#xA;&lt;p&gt;The tides are so predictable that Atlantis says &lt;strong&gt;it can tell how much energy these turbines will generate every fifteen minutes for the next twenty-five years.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;What kind of information goes into such a long-term prediction? Is it just the relative positions of the Sun, Earth, and Moon, or something more? I ask because those positions can be calculated for thousands of years, there wouldn't be a cut off at only 25 years, so I assume there's more that goes into it.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-03-21T15:10:16.333" Title="What goes into a tide power prediction for every fifteen minutes over the next twenty five years?" Tags="|oceanography|ocean-currents|tides|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="16503" PostTypeId="2" ParentId="15536" CreationDate="2019-03-18T09:05:07.440" Score="4" Body="&lt;p&gt;No it is not possible because the continental crust's density is lower.&#xA;Conversely, &lt;a href=&quot;https://en.wikipedia.org/wiki/Oceanic_crust&quot; rel=&quot;nofollow noreferrer&quot;&gt;oceanic plates&lt;/a&gt; can subduce under continental ones because they are heavier. This is because &lt;a href=&quot;https://en.wikipedia.org/wiki/Continental_crust&quot; rel=&quot;nofollow noreferrer&quot;&gt;continental crusts&lt;/a&gt; are formed by &lt;a href=&quot;https://en.wikipedia.org/wiki/Granite&quot; rel=&quot;nofollow noreferrer&quot;&gt;granites&lt;/a&gt; and sedimentary materials. Their density rounds &lt;span class=&quot;math-container&quot;&gt;$2,7g/cm^3$&lt;/span&gt;, granites ones, while oceanic crust rounds &lt;span class=&quot;math-container&quot;&gt;$3g/cm^3$&lt;/span&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Basalt&quot; rel=&quot;nofollow noreferrer&quot;&gt;basalts&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Gabbro&quot; rel=&quot;nofollow noreferrer&quot;&gt;gabbros&lt;/a&gt; ones.&#xA;Oceanic plates start to subduce at a certain age. Presently there are not pre-Jurassic oceanic plates that do it. This is related with the stack of hidrated sediments over the igneous materials.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An exception to this are &lt;a href=&quot;https://en.wikipedia.org/wiki/Ophiolite&quot; rel=&quot;nofollow noreferrer&quot;&gt;ophiolites&lt;/a&gt;, where oceanic plate obduce continental one. This is not happening presently at any place on Earth, but there are fossilized examples as &lt;a href=&quot;https://en.wikipedia.org/wiki/Semail_Ophiolite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Semail Ophiolite&lt;/a&gt; at Oman. &lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorUserId="14253" LastEditDate="2019-03-18T17:17:09.477" LastActivityDate="2019-03-18T17:17:09.477" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16504" PostTypeId="2" ParentId="15992" CreationDate="2019-03-18T11:02:38.777" Score="5" Body="&lt;p&gt;Continental collision as Indian Plate with Eurasia one finish in a merge, but the process is slow. An example of merged plates is Iberian Subplate that is presently considered Eurasian Plate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The collision creates mountain chains as Himalaya. Presently Indian Plate is a separated system because it has still a big granite root under the mountains. While erosion happens, the new geophysical echillibrium bounces new relief to the chain and the root starts to be sutured. There is stil some decenes of kilometers of granite root under the Himalaya, so the chain is still a plate limit. &lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-07-13T22:02:11.543" LastActivityDate="2019-07-13T22:02:11.543" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16505" PostTypeId="2" ParentId="16501" CreationDate="2019-03-18T12:43:47.997" Score="7" Body="&lt;p&gt;Tide prediction at some locale is more of an empirical art rather than an analytic science. It essentially is a reduction of decades or centuries of historical tide levels at the locale to Fourier-like coefficients. Tides at a locale are modeled as a sum of various frequency components, each with a magnitude and a phase offset from some reference. The frequency components are based on the Earth's rotation about its axis, the orbit of the Moon about the Earth, and the orbit of the Earth-Moon system about the Sun. Given a sufficiently long historical record at some locale, mathematical techniques enable teasing the magnitudes and phases for each frequency component from the record for that locale.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are issues with this approach that limit the usefulness of these tidal coefficients for future predictions. The utility of the computed coefficients to predict future tides declines as time passes. The coefficients occasionally need to be recomputed. One issue is that there's a lot of noise in the historical records; a decent storm will temporarily make the tides behave differently than the record would suggest. This noisiness alone means that the computed tidal coefficients are not perfect. This makes the accuracy of predicted tides decline over time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another issue is that neither the Earth's rotation rate nor the Moon's orbital rate is constant; the tidal models assume they are. Even without the noise, a set of tidal coefficients from a hundred years ago would be worthless today because of the small changes in those rates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yet another issue is that the oceans themselves change over time because of sedimentation, changes in mean sea level, and changes in the shapes of the oceans due to plate tectonics. An estuary filling with sediment will drastically change the high frequency overtones that result from interactions between the driving frequencies and the coast. The oceans' responses to each of the driving frequencies is a set of amphidromic systems. Each amphidromic system comprises a central point around which water waves rotate at the driving frequency. The nature of these amphidromic systems slowly change over time as the oceans change.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2019-03-18T12:43:47.997" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16506" PostTypeId="1" CreationDate="2019-03-18T13:17:36.397" Score="3" ViewCount="17" Body="&lt;p&gt;Let's assume a small (and smooth) vertical deformation of the seabed. If done quickly, I can consider it a vertical force generating an acoustic wave in the water, where every particle of water returns to its original position. That is provided the deformation is small enough to use infinitesimal strain theory. However, if done slowly, I imagine a flow where water is simply flowing off the deformation, even if any one 'water particle' is flowing only a small (horizontal) distance. And back in when the deformation retracts. Which parameter controls it's a flow or an acoustic deformation? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The seabed is made of very soft mud, in case that makes a difference. I see an earthquake wave on a vertical geophone, but barely on a hydrophone.&lt;/p&gt;&#xA;" OwnerUserId="15462" LastActivityDate="2019-03-18T13:17:36.397" Title="transition elastic deformation to flow" Tags="|geophysics|oceanography|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16507" PostTypeId="1" CreationDate="2019-03-18T20:15:57.247" Score="1" ViewCount="58" Body="&lt;p&gt;I am trying to parse an old geologic description of stone suitable for use as road metal:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Care must be taken to distinguish the difference between the hardness&#xA;  of a stone and its toughness...Toughness in granites, syenites, and&#xA;  the like is occasioned by the disposition and size of the crystals&#xA;  forming them, these crystals being more interlocked in the tougher&#xA;  varieties of these stones than in the others.... Although we have&#xA;  described syenite as being made of quartz, feldsparand hornblende&#xA;  (excluding the few accessory minerals, for simplicity), we have not&#xA;  stated in what particular quantities these may exist, and this is an&#xA;  important factor in the inquiry. It will be found that the proportions&#xA;  vary considerably and on this the differences in durability and&#xA;  specific gravity are largely dependent. There cannot be much doubt&#xA;  that in the syenites commonly used as road metal, the rate of&#xA;  decomposition of the feldspar is the principal source of the&#xA;  superiority of one kind over another. The most durable syenite, then,&#xA;  is that which has the least feldspar, and, we may add, the least iron&#xA;  in that mineral. Syenites which contain an excess of feldspar,&#xA;  generally have a low specific gravity, unless the hornblende is&#xA;  superabundant. Those hornblendic granites, in which the feldspar has a&#xA;  tendency to occur in rather large crystals here and there, cannot be&#xA;  expected to make such good road-metal as those kinds of syenite which&#xA;  do not exhibit this feature, are fine-grained, have comparatively&#xA;  little feldspar, but much hornblende.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, the question is how to figure out which rocks meet the criteria in the quote. For example, in New Hampshire some of the available syenites are as follows from sources like minedat:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Hornblende-biotite quartz syenite to syenite (Late Ordovician)&#xA;Hornblende (or alkalic amphibole) syenite (Jurassic)&#xA;Nepheline-sodalite-hastingsite syenite (Jurassic)&#xA;Porphyritic syenite - Hastingsite or hornblende and (or) hedenbergite are present. (Jurassic)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;So, the question is how can I tell if a minedat description of a plutonic rock is favorable according to the criteria of the quoted passage?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastEditorDisplayName="user12525" LastEditDate="2019-04-14T13:58:56.627" LastActivityDate="2019-04-14T13:58:56.627" Title="How can I identify &quot;tough&quot; (mixed) granites?" Tags="|geology|petrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16508" PostTypeId="1" CreationDate="2019-03-18T22:47:02.420" Score="5" ViewCount="82" Body="&lt;p&gt;I've always thought that river flooding would always be the same at the same river stage.  For example, if the river stage is at 20' flooding at location &quot;x&quot; would always be at the same depth.  However, current flood stages along the Mississippi River are not correlating with past photos at the same flood stages in the past.  I'm not aware of there being any major changes upstream that would accommodate the reduced volume we are now seeing.  We are seeing roughly a foot difference (less flooding) along a 4-5 mile stretch of the river at the same location as little as 8 years ago.  &lt;strong&gt;What other variables could result in different flood inundation at a given river stage?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user11318" LastActivityDate="2019-05-17T21:04:48.113" Title="How can flood inundation vary at the same river stage?" Tags="|water|rivers|flooding|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16509" PostTypeId="2" ParentId="16507" CreationDate="2019-03-19T05:16:18.900" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;So, the question is how can I tell if a minedat description of a plutonic rock is favorable according to the criteria of the quoted passage?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No. The description doesn't say how much feldspar is in the rock. It could be 5%, or it could be 20%. It also doesn't say anything about the iron content of the feldspar (although with some petrological hand waving you can assume by the presence of other minerals).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The nepheline syenite is going to have no feldspar (or very little), because it's usually either nepheline or feldspar, not both. But, we don't know whether nepheline is any good for the purpose.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm also wondering why is hornblende considered superior because it is a mineral that cleaves and breaks very easily.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing that is important is that they stress the fine grain size. Usually rocks with fine grain size are tougher than those with coarser.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-03-19T05:16:18.900" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16510" PostTypeId="1" AcceptedAnswerId="16517" CreationDate="2019-03-19T05:50:12.957" Score="6" ViewCount="105" Body="&lt;p&gt;The anouncement published in Science &lt;a href=&quot;https://www.sciencemag.org/news/2019/03/mini-tremors-detected-mars-first-time&quot; rel=&quot;noreferrer&quot;&gt;Mini tremors detected on Mars for first time&lt;/a&gt; says that the Mars lander InSight is detecting &lt;a href=&quot;https://en.wikipedia.org/wiki/Microseism&quot; rel=&quot;noreferrer&quot;&gt;microseisms&lt;/a&gt; on Mars after various vibrations produced by the lander and its interaction with the wind are excluded.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The above linked Wikipedia article says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In seismology, a microseism is defined as a faint earth tremor caused by natural phenomena. Sometimes referred to as a &quot;hum&quot;, it should not be confused with the anomalous acoustic phenomenon of the same name. The term is most commonly used to refer to the dominant background seismic and electromagnetic noise signals on Earth, &lt;strong&gt;which are caused by water waves in the oceans and lakes.&lt;/strong&gt; Characteristics of microseism are discussed by Bhatt. Because the ocean wave oscillations are statistically homogenous over several hours, the microseism signal is a long-continuing oscillation of the ground. The most energetic seismic waves that make up the microseismic field are Rayleigh waves, but Love waves can make up a significant fraction of the wave field, and body waves are also easily detected with arrays. Because the conversion from the ocean waves to the seismic waves is very weak, the amplitude of ground motions associated to microseisms does not generally exceed 10 micrometers. (several citations available in original article)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;We can exclude large surface bodies of water on Mars, so the vibrations must be coming from other sources.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What could be causing microseisms on Mars?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2019-03-19T23:01:02.573" Title="What could be causing microseisms on Mars?" Tags="|mars|microseism|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16511" PostTypeId="2" ParentId="12157" CreationDate="2019-03-19T09:22:56.380" Score="4" Body="&lt;p&gt;&lt;strong&gt;Yes and no.&lt;/strong&gt; Caribbean Sea and Gulf of Mexico have sedimentary materials and rocks at the top, but seabed &lt;em&gt;sensu stricto&lt;/em&gt; is composed by sediments and not by rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oceanic Crust is composed by &lt;a href=&quot;https://en.wikipedia.org/wiki/Basalt&quot; rel=&quot;nofollow noreferrer&quot;&gt;basalts&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Gabbro&quot; rel=&quot;nofollow noreferrer&quot;&gt;gabbros&lt;/a&gt;, both igneous rocks as you notice, and sedimentary materials above. We know that because of drillings and fossilized &lt;a href=&quot;https://en.wikipedia.org/wiki/Ophiolite&quot; rel=&quot;nofollow noreferrer&quot;&gt;ophiolites&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UL4RD.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UL4RD.gif&quot; alt=&quot;Ophiolite cross profile&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: &lt;a href=&quot;http://earth.s.kanazawa-u.ac.jp/ishiwata/ophiol_e.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;earth.s.kanazawa&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Gulf_of_Mexico&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gulf of Mexico&lt;/a&gt; is not an exception and has &lt;a href=&quot;https://en.wikipedia.org/wiki/Sediment&quot; rel=&quot;nofollow noreferrer&quot;&gt;sediments&lt;/a&gt; at the top, as said in this paper:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Most sediment originates from the adjacent land, primarily via fluvial transport. Direct precipitation of calcium carbonate and evaporate minerals takes place primarily on the Florida and Yucatán platforms and some coastal lagoons. The deep environments tend to be dominated by mud in a combination of terrigenous and biogenic sediments.&quot; (Davids Jr, R.A.,2017) &lt;a href=&quot;https://link.springer.com/chapter/10.1007/978-1-4939-3447-8_3&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Caribbean_Sea&quot; rel=&quot;nofollow noreferrer&quot;&gt;Caribbean Sea&lt;/a&gt; is neither an exception, as remarks Encyclopedia Britannica:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;The ancient sediments overlying the seafloor of the Caribbean, as well as of the Gulf of Mexico, are about a half mile (about one kilometre) in thickness, with the upper strata representing sediments from the Mesozoic and Cenozoic eras (from about 252 million years ago to the present) and the lower strata presumably representing sediments of the Paleozoic and Mesozoic eras (from about 541 to 66 million years ago)&quot; (Menzies,R.J. et al, 2019) &lt;a href=&quot;https://www.britannica.com/place/Caribbean-Sea&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This article says there is one kilometre of sedimentary materials, enough to &lt;a href=&quot;https://en.wikipedia.org/wiki/Diagenesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;diagenesis&lt;/a&gt; to take place and so, there are &lt;a href=&quot;https://en.wikipedia.org/wiki/Sedimentary_rock&quot; rel=&quot;nofollow noreferrer&quot;&gt;sedimentary rocks&lt;/a&gt; under the unconsolided sediments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At open oceans diagenesis may have still do not have place and there is only the ophiolitic sequence with thin sediments, but, as you can read &lt;a href=&quot;https://earthscience.stackexchange.com/a/12155/12525&quot;&gt;in this related answer&lt;/a&gt;, Caribean Sea have old igneous rocks with a big stack of sediments above that have litified to sedimentary rocks (coming from continental rivers and carbonaceous platforms), becoming the biggest oil source zone on Earth after Arabian Gulf. &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;1) &lt;a href=&quot;https://link.springer.com/chapter/10.1007/978-1-4939-3447-8_3&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Davis R.A. (2017)&lt;/strong&gt; &lt;em&gt;&quot;Sediments of the Gulf of Mexico.&quot;&lt;/em&gt; In: Ward C. (eds) &lt;strong&gt;Habitats and Biota of the Gulf of Mexico: Before the Deepwater Horizon Oil Spill&lt;/strong&gt;. Springer, New York, NY&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) &lt;a href=&quot;https://www.britannica.com/place/Caribbean-Sea&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Menzies, R.J., Ogden, J.C. (2019)&lt;/strong&gt; &lt;em&gt;&quot;Caribbean Sea.&quot;&lt;/em&gt; In: &lt;strong&gt;Encyclopedia Britannica&lt;/strong&gt;.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-03-19T16:51:24.823" LastActivityDate="2019-03-19T16:51:24.823" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16512" PostTypeId="2" ParentId="16510" CreationDate="2019-03-19T14:07:34.110" Score="6" Body="&lt;p&gt;I think that the mechanism suggested in the article fits the bill the best:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;On Earth, microseisms are ubiquitous, caused largely by the sloshing&#xA;  of the ocean by storms and tides. Mars, despite the dreams of science&#xA;  fiction writers, has no present-day oceans. Instead, &lt;strong&gt;this newly&#xA;  discovered noise is likely caused by low-frequency pressure waves from&#xA;  atmospheric winds that rattle the surface, inducing shallow,&#xA;  longer-period waves in the surface, called Rayleigh waves&lt;/strong&gt;, Lognonné&#xA;  said.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;See e.g., &lt;a href=&quot;https://www.lpi.usra.edu/meetings/lpsc2012/pdf/1994.pdf&quot; rel=&quot;noreferrer&quot;&gt;https://www.lpi.usra.edu/meetings/lpsc2012/pdf/1994.pdf&lt;/a&gt; , for a modeling study of the microseismic events on Mars due to wind. &lt;/p&gt;&#xA;" OwnerUserId="12155" LastActivityDate="2019-03-19T14:07:34.110" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16513" PostTypeId="1" CreationDate="2019-03-19T17:34:52.683" Score="14" ViewCount="4580" Body="&lt;p&gt;We've had an unusual winter this year, with a late cold snap that is causing people's underground water lines to freeze. Now that the weather has warmed up quite a bit, even more people's lines are freezing, because the frost is being pushed down even deeper by the thawing ground above it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What causes this phenomenon? Why does the frost not simply thaw from top to bottom after it warms up? Why does it continue to go deeper?&lt;/p&gt;&#xA;" OwnerUserId="702" LastEditorUserId="11908" LastEditDate="2019-03-19T19:46:47.823" LastActivityDate="2022-12-19T15:56:01.757" Title="Why does the frost depth increase when the surface temperature warms up?" Tags="|cryosphere|winter|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16514" PostTypeId="1" CreationDate="2019-03-19T17:36:50.787" Score="6" ViewCount="174" Body="&lt;p&gt;Supposing you had an unusually cold winter and a region that does not normally have permafrost. How deep would the frost have to go before it was too deep for it to thaw fully over summer? &lt;/p&gt;&#xA;" OwnerUserId="702" LastEditorUserId="11908" LastEditDate="2019-03-19T18:20:30.030" LastActivityDate="2022-09-02T13:46:48.337" Title="How deep does the frost have to go before it becomes permafrost?" Tags="|cryosphere|permafrost|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16515" PostTypeId="2" ParentId="16513" CreationDate="2019-03-19T17:57:41.453" Score="26" Body="&lt;p&gt;That's is due to the slow diffusion of heat into the ground. Unlike a liquid, pieces of soil can't move around, therefore, in the absence of liquid water, heat can only be transferred by &lt;a href=&quot;https://en.wikipedia.org/wiki/Thermal_conduction&quot; rel=&quot;nofollow noreferrer&quot;&gt;conduction&lt;/a&gt;, a process that follows the diffusion equations and it is very slow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This means that if there is a heat wave, or a cold snap, their effect will reach deep layers of the soil with a delay, the deeper the longer the delay and the more dampened the wave will arrive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This figure shows a heat wave in the soil&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/824Ko.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/824Ko.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(figure from &lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/soil-temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;Soil Temperature at ScienceDirect&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, the plot shows that there was a peak in temperature of about 27°C at the surface (0m) at time t=6h, but that peak in temperature slowly diffused downwards, such that at a depth of 0.2 m, the peak happened at time t=8h reaching only about 23°C, and at a depth of 0.4 m it arrived even later, at about t=18h and reached only 21°C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In you case, what is happening that the cold snap is still &quot;traveling&quot; down the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An alternative way to understand this, is that the cold snap cooled the ground so that a layer below the surface can be now at, let's say -5°C, and it is on top of a deeper layer at +1°C, where the water pipe is located. What that deeper layer feels is not what happens in the surface, that is nice and warm, it feels the temperature of the layer right on top of it, that is still very cold. So that deeper layer will cool down and eventually freeze. Freezing as well  the water line with it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, and to address some great comments. The current freezing of underground water lines responds to a past forcing. Therefore, it have nothing to do with current weather and is not the thawing ground what pushes the frost down. It is just the normal curse of events in the propagation of a cold/hot wave down into the ground.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-03-20T21:02:58.880" LastActivityDate="2019-03-20T21:02:58.880" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16516" PostTypeId="2" ParentId="16514" CreationDate="2019-03-19T18:20:10.170" Score="6" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Permafrost&quot; rel=&quot;noreferrer&quot;&gt;Permafrost&lt;/a&gt; is permanently frozen ground. However, most definition qualify it as permafrost if it remains frozen for at least two years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The speed at which a temperature change travels down the ground depends on the thermal conductivity, and it varies between soils. As a thumb rule, the temperature at 10 m depth is pretty much constant and equal to the mean yearly temperature at the surface. This means that 10m is roughly the distance the heat wave travels in a year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That means that if you manage to freeze the ground below 10m the next summer won't be able to thaw it within a year no matter how hot it is, so it will stay frozen for at least one and a half years. How much longer it will stay frozen will depend on the exact temperatures and lengths of the winter that created the frost layer, the winters after that and the summers in between. Without more details it is impossible to give a number.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Said that, a single cold snap is unlikely to significantly affect the temperature very deep into the ground, you need an extended period of cold weather and many cold winters in a row to do that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An exceptionally cold winter followed by a mild summer could create a layer of frost that survive two years, but its depth will depend of the actual temperature profile over that period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyway, if that frost layer thaw is not going to be on the next summer, but much later, because the heat will take a long time to travel down there. More on these delay on &lt;a href=&quot;https://earthscience.stackexchange.com/a/16515/11908&quot;&gt;this answer&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-03-19T18:20:10.170" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16517" PostTypeId="2" ParentId="16510" CreationDate="2019-03-19T18:33:04.113" Score="4" Body="&lt;p&gt;In addition to @Erik answer, rocks as any other material dilates when it gets hotter and contracts as it gets colder. On Earth's such phenomena, and differences in temperature within rocks  leads even to the cracking of rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That could be another source of microseismicity, because the thermal amplitude in Mars is huge. The temperatures on the two Viking landers, &lt;a href=&quot;http://www.astronomycafe.net/FAQs/q2681x.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;measured at 1.5 meters above the surface ranged from -17.2°C to -107°C&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another one could be meteorite and micrometeorites impacts, that could be more common there due to the much thinner atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, Mars interior is getting colder, therefore its inner layers are contracting and its diameter slowly shrinking. That leads to &lt;a href=&quot;https://en.wikipedia.org/wiki/Thrust_fault&quot; rel=&quot;nofollow noreferrer&quot;&gt;thrust faults&lt;/a&gt;, that have been observed in other solar system bodies (specially smaller moons and &lt;a href=&quot;https://www.nasa.gov/mission_pages/LRO/news/shrinking-moon.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;even our Moon&lt;/a&gt;). This thrusting also can cause seismicity and microiseismicity without any doubt.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-03-19T23:01:02.573" LastActivityDate="2019-03-19T23:01:02.573" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16518" PostTypeId="1" CreationDate="2019-03-20T02:49:09.477" Score="3" ViewCount="178" Body="&lt;p&gt;I'm trying to write a program that would determine the magnitude and epicenter of an earthquake. From &lt;a href=&quot;http://www.dartmouth.edu/~ears5/handouts/EQ_distance.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.dartmouth.edu/~ears5/handouts/EQ_distance.html&lt;/a&gt;, the distance of the epicenter can be calculated with &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$d = (ts-tp)/(1/vs)-(1/vp)$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I'm not really sure as to what the values Vs and Vp are. From the travel time graph Vs and Vp varies with the distance of the sensor from the earthquake. Given that I have 3 sensors with given latitude and longitude, from which I am able to get the lag time, is there anyway I can estimate the Vs and Vp from these variables?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Otherwise, is there any other way I could get the distance of the sensors from the epicenter?&lt;/p&gt;&#xA;" OwnerUserId="15470" LastEditorUserId="725" LastEditDate="2019-03-20T05:39:53.950" LastActivityDate="2019-03-20T12:03:16.053" Title="How do I get the velocity of the P-wave or S-wave without using the travel time graph?" Tags="|earthquakes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16519" PostTypeId="1" CreationDate="2019-03-20T06:43:13.093" Score="2" ViewCount="195" Body="&lt;p&gt;I want to plot some &lt;a href=&quot;https://en.wikipedia.org/wiki/Tephigram&quot; rel=&quot;nofollow noreferrer&quot;&gt;tephigrams&lt;/a&gt;.&lt;br /&gt;&#xA;Where can I find pressure, temperature and dewpoint data in text format?&lt;/p&gt;&#xA;" OwnerUserId="15471" LastEditorUserId="11908" LastEditDate="2019-03-20T21:07:48.323" LastActivityDate="2019-03-20T21:07:48.323" Title="Data for plotting tephigrams" Tags="|meteorology|geography|measurements|open-data|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16521" PostTypeId="1" AcceptedAnswerId="16523" CreationDate="2019-03-20T06:55:08.823" Score="1" ViewCount="1724" Body="&lt;p&gt;In Scott Manley's new video &lt;a href=&quot;https://www.youtube.com/watch?v=fpaxvjFh-qA&quot; rel=&quot;nofollow noreferrer&quot;&gt;173 Kiloton Explosion Over Bering Sea Was Asteroid Breaking Up&lt;/a&gt; a bit after &lt;code&gt;01:30&lt;/code&gt; he says&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The good news is that in these days of near-limitless data storage capabilities the internet has a long memory, and we can look at the Himawari satellite which is a weather satellite in geostationary orbit that covers the area in question. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I normally view Himawari images from &lt;a href=&quot;https://www.jma.go.jp/en/gms/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.jma.go.jp/en/gms/&lt;/a&gt; and if you open an image in a new window and look at the URL you can guess how to change the date and time into the past. That works for several days or a week, but not three months.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Where are three-month-old or possibly even year-old Himawari weather satellite images available to the public?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;As an exercise, per: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://space.stackexchange.com/q/34896/12102&quot;&gt;How was the 18 December 2018 Bering Sea Fireball detected and characterized? Was it a serendipity or a weather satellite?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://cneos.jpl.nasa.gov/fireballs/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://cneos.jpl.nasa.gov/fireballs/&lt;/a&gt; &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;the event was at &lt;code&gt;2018-12-18 23:48:20 UTC&lt;/code&gt; and &lt;code&gt;56.9N 172.4E&lt;/code&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2019-03-20T07:12:28.300" LastActivityDate="2019-03-21T03:31:25.653" Title="Where are old Himawari weather satellite images available to the public? Is the 18-Dec-2018 Bearing Sea fireball still there?" Tags="|open-data|meteorite|earth-observation|weather-satellites|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16522" PostTypeId="1" AcceptedAnswerId="16536" CreationDate="2019-03-20T07:01:48.480" Score="7" ViewCount="233" Body="&lt;p&gt;I would like to find sources of topographical data for Earth's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've looked in &lt;a href=&quot;https://gis.stackexchange.com/&quot;&gt;GIS SE&lt;/a&gt; and &lt;a href=&quot;https://opendata.stackexchange.com/questions&quot;&gt;Open Data SE&lt;/a&gt; but haven't found a good answer to this so I though I'd ask here in Earth Science.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Are there public sites where I can download free topographical data; tables of surface height above a reference surface? &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Is it possible to download them in text or tabular form?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I'm looking for resolution of something of the order of 5 meters vertically an 10 horizontally, but there's no specific hard requirement.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2019-03-21T00:54:16.397" LastActivityDate="2020-01-19T04:45:34.030" Title="Public sources of topographical data of Earth?" Tags="|remote-sensing|open-data|topography|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16523" PostTypeId="2" ParentId="16521" CreationDate="2019-03-20T07:18:48.283" Score="3" Body="&lt;p&gt;You need to go this site - &lt;a href=&quot;http://www.jma.go.jp/jma/jma-eng/satellite/dissemination.html#archive&quot; rel=&quot;nofollow noreferrer&quot;&gt;Himawari Archive&lt;/a&gt; and then it depends on what category of user you are and then obtain the imagery that way. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE -&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On OP's request I am recording the information I got from JMA when I wanted to access Himawari's images. You need to specify what kind of user you are &lt;/p&gt;&#xA;&#xA;&lt;p&gt;a) research&#xA;b) commercial.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Presuming research you can obtain Himawari images from the following institutions as mentioned in the original link I provided&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The following four Japanese institutions operate Himawari-8 data archiving and redistribution services on a best-effort basis for research, development and education:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;1) JAXA Himawari Monitor (Japan Aerospace Exploration Agency)&#xA;          &lt;a href=&quot;http://www.eorc.jaxa.jp/ptree/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.eorc.jaxa.jp/ptree/index.html&lt;/a&gt;&#xA;      Himawari-8 Data Download and Processing System (Data Integration and Analysis System Program)&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;2) &lt;a href=&quot;http://himawari.diasjp.net/expert/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://himawari.diasjp.net/expert/&lt;/a&gt;&#xA;      Center for Environmental Remote Sensing (CEReS)&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;3) Chiba University&#xA;          &lt;a href=&quot;http://www.cr.chiba-u.jp/databases/GEO/H8_9/FD/index_jp.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.cr.chiba-u.jp/databases/GEO/H8_9/FD/index_jp.html&lt;/a&gt; &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;4)    Himawari Satellite Project (NICT : National Institute of Information and Communications Technology)&#xA;          &lt;a href=&quot;http://sc-web.nict.go.jp/himawari/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://sc-web.nict.go.jp/himawari/&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Users must register to download data from each institution and observe the individual data usage policies. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;If you are asking how I would do it then I must mention I use a python software called&#xA;&lt;a href=&quot;https://satpy.readthedocs.io/en/latest/&quot; rel=&quot;nofollow noreferrer&quot;&gt;SatPy&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then I go to this URL - &lt;a href=&quot;ftp://ftp.ptree.jaxa.jp/jma/netcdf/&quot; rel=&quot;nofollow noreferrer&quot;&gt;JAXA FTP URL&lt;/a&gt;( I think it is only visible if you are registered) and then download the data for whatever year I want. Then write a small script using a SatPy reader and view the data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;NOTE&lt;/strong&gt; For the last points you are better off asking questions either on SatPy and for the data itself writing email to JAXA. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-03-21T03:31:25.653" LastActivityDate="2019-03-21T03:31:25.653" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16524" PostTypeId="2" ParentId="16518" CreationDate="2019-03-20T08:39:01.660" Score="3" Body="&lt;p&gt;I think that it is possible with fours stations yes, not with three.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;With the assumption of (roughly) homogeneous velocities we get the following forward problem&lt;/strong&gt;. Assuming that &lt;span class=&quot;math-container&quot;&gt;$v_p$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$v_s$&lt;/span&gt; are constants between the Earthquake and all your receivers yields the following system:&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{align}&#xA;    d &amp;amp;= \sqrt{\Delta x^2 + \Delta y^2 + \Delta z^2}=\text{3 knowns, 3 unknowns},\quad \text{for} \left\{ \begin{array}{rl} \Delta x &amp;amp;= x_\text{earthquake}-x_\text{receiver} \\ \Delta y &amp;amp; = y_\text{earthquake} - y_\text{receiver} \\ \Delta z &amp;amp; = z_\text{earthquake} - z_\text{receiver}  \end{array} \begin{split} \end{split}\right.,\\&#xA;\Delta t &amp;amp; = t_s - t_p = \text{measured},\\&#xA;p &amp;amp;= \left(\frac{1}{v_s} - \frac{1}{v_p} \right) = \text{1 unknown}.&#xA;\end{align}&lt;/span&gt;&#xA;Restating the equation of your question then gives the forward problem:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ \Delta t = p d.$$&lt;/span&gt;&#xA;For example, for &lt;span class=&quot;math-container&quot;&gt;$v_p=2000$&lt;/span&gt; m/s and &lt;span class=&quot;math-container&quot;&gt;$v_s=1200$&lt;/span&gt; m/s, we find &lt;span class=&quot;math-container&quot;&gt;$p=1/3000$&lt;/span&gt; and can compute e.g. with &lt;span class=&quot;math-container&quot;&gt;$d = 600$&lt;/span&gt; that &lt;span class=&quot;math-container&quot;&gt;$\Delta t = 600/3000 =0.2$&lt;/span&gt; s.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Now, we must set=up the inverse problem&lt;/strong&gt;. You generally need at least as many equations as unknowns. In this case we have 4 unknowns (the velocity and the &lt;span class=&quot;math-container&quot;&gt;$(x,y,z)$&lt;/span&gt; earthquake location). That means that we need 4 (unique) equations. I think that the simplest way of obtaining 4 unique equations is to combine 4 measurements:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ p\begin{pmatrix} d_1 \\ d_2 \\ d_3 \\ d_4 \end{pmatrix} = \begin{pmatrix} \Delta t_1 \\ \Delta t_2 \\ \Delta t_3 \\ \Delta t_4 \end{pmatrix}, $$&lt;/span&gt;&#xA;Denoting with &lt;span class=&quot;math-container&quot;&gt;$x_{1,2,3,4}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$y_{1,2,3,4}$&lt;/span&gt; the latitude and longitude of the receivers, and assuming measurements at the surface, we obtain:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ p\begin{pmatrix} \sqrt{(x_\text{earthquake}-x_1)^2 + (y_\text{earthquake}-y_1)^2 + z_\text{earthquake}^2} \\ \sqrt{(x_\text{earthquake}-x_2)^2 + (y_\text{earthquake}-y_2)^2 + z_\text{earthquake}^2} \\ \sqrt{(x_\text{earthquake}-x_3)^2 + (y_\text{earthquake}-y_3)^2 + z_\text{earthquake}^2 } \\ \sqrt{(x_\text{earthquake}-x_4)^2 + (y_\text{earthquake}-y_4)^2 + z_\text{earthquake}^2} \end{pmatrix} = \begin{pmatrix} \Delta t_1 \\ \Delta t_2 \\ \Delta t_3 \\ \Delta t_4 \end{pmatrix}. $$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Finally, we must solve the inverse problem&lt;/strong&gt;. Unfortunately, the system is non-linear (the unknowns are 'hidden' in the root of the square and can't be separated). You must therefore use some non-linear solver. For example, in MATLAB you can do this&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;% True earthquake location&#xA;x_earthquake=0;&#xA;y_earthquake=0;&#xA;z_earthquake=1000;&#xA;&#xA;% True station locations&#xA;x_1 = 1000; y_1 = 1000;&#xA;x_2 =  500; y_2 = -300;&#xA;x_3 = -400; y_3 = -100;&#xA;x_4 =  -10; y_4 = 800;&#xA;X = [x_1;x_2;x_3;x_4];&#xA;Y = [y_1;y_2;y_3;y_4];&#xA;&#xA;% True velocity structure&#xA;p0 = 1/3000;&#xA;&#xA;% Forward equation (F(1)=x_eartquake, F(2)=y_earthquake, F(3)=z_earthquake, F(4)=p. &#xA;t =@(F) F(4) * sqrt( (F(1)-X).^2 + (F(2)-Y).^2 + F(3).^2);&#xA;&#xA;% True recordings&#xA;measured_times = t([x_earthquake,y_earthquake,z_earthquake,p0]);&#xA;&#xA;% Misfit function (=0 at optimum)&#xA;G =@(F) t(F) - measured_times;&#xA;&#xA;% Invert&#xA;%options = optimoptions('fsolve','FiniteDifferenceType','central'); % using these will give better results in MATLAB&#xA;%F_inv = fsolve( G, [1000,1000,1000,0.1],options)&#xA;F_inv = fsolve( G, [1000,1000,1000,0.1])&#xA;x_earthquake_inv = F_inv(1)&#xA;y_earthquake_inv = F_inv(2)&#xA;z_earthquake_inv = F_inv(3)&#xA;p_inv            = F_inv(4)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;If you copy this into &lt;a href=&quot;https://octave-online.net/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://octave-online.net/&lt;/a&gt;, for example, it will find an earthquake at (0,0,1000) and p=1/3000, with some small errors due to the non-linear solver.&lt;/p&gt;&#xA;" OwnerUserId="12155" LastEditorUserId="12155" LastEditDate="2019-03-20T12:03:16.053" LastActivityDate="2019-03-20T12:03:16.053" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16525" PostTypeId="2" ParentId="16519" CreationDate="2019-03-20T13:15:37.990" Score="3" Body="&lt;p&gt;Since OP wants data in text format to plot pressure, temperature and dew point data this site &lt;a href=&quot;http://weather.uwyo.edu/upperair/sounding.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;University of Wyoming soundings map&lt;/a&gt; does provide data in a text format as shown in this example for &lt;a href=&quot;http://weather.uwyo.edu/cgi-bin/sounding?region=europe&amp;amp;TYPE=TEXT%3ALIST&amp;amp;YEAR=2019&amp;amp;MONTH=03&amp;amp;FROM=2000&amp;amp;TO=2000&amp;amp;STNM=10410&quot; rel=&quot;nofollow noreferrer&quot;&gt;Essen Germany&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-03-20T13:22:26.233" LastActivityDate="2019-03-20T13:22:26.233" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16526" PostTypeId="2" ParentId="16501" CreationDate="2019-03-20T15:50:22.367" Score="4" Body="&lt;p&gt;As another answer has stated, tides can broadly be predicted far ahead by harmonic analysis (which is similar to taking a fourier transform of the tidal signal, but only allowing frequencies that correspond to various astronomical periods of the sun, the moon, and interactions between the two).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are some caveats to this. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;As David Hammen has noted, water depths may change over time due to changes in sediment. In many of the tidal sites that are currently being developed the speed of the current means that the seabed is scoured rock, without sediment, but in some areas this change may nevertheless become significant, perhaps over a 25-year timescale.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Superimposed on this astronomical signal can be significant (up to approx. 0.5 m/s) short-term variations due to meteorological effects such as surface winds and storm surges. This limits the accuracy with which one can predict the speed of tidal flow more than a few days ahead, but does not give a rationale for the 25-year figure.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;As noted by &lt;a href=&quot;http://www.doi.org/10.1177/0957650912470081&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt; and others, while the astronomical (rather than meteorological) component of water elevations resulting from tides can be fully described using a sufficient number of harmonic constituents, the same is not always true of flow velocities. This is because the shape of landforms and of the seabed can cause additional periodic changes in the velocity at a given location which do not correspond to astronomical frequencies. An example is the tendency of a &quot;jet&quot; to form downstream of a constriction at certain phases of the tide. Nevertheless, harmonic analysis can still usually provide a close approximation and, once again, this does not provide a rationale for the 25-year limit given.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I suspect that 25 years is simply a number plucked from the air to mean &quot;a long time&quot;, perhaps informed (as noted in a comment) by that being the intended lifetime of the turbines.&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2019-03-21T15:10:16.333" LastActivityDate="2019-03-21T15:10:16.333" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16527" PostTypeId="1" AcceptedAnswerId="16539" CreationDate="2019-03-20T16:32:50.893" Score="3" ViewCount="982" Body="&lt;p&gt;Advection of a scalar quantity, such as temperature (&lt;em&gt;T&lt;/em&gt;), by the horizontal wind, is defined as follows:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$-\textbf{U}\cdot\nabla T$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$\textbf{U}$&lt;/span&gt; is the horizontal wind vector, &lt;span class=&quot;math-container&quot;&gt;$\textbf{U}=(u,v)$&lt;/span&gt;, being &lt;span class=&quot;math-container&quot;&gt;$u$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$v$&lt;/span&gt; its zonal and meridional components, respectively (&lt;a href=&quot;http://glossary.ametsoc.org/wiki/Advection&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To compute it with gridded data, it is convenient to use finite differences (or similar numerical approaches), as pointed &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9634/how-to-compute-du-dx-and-dv-dy-in-moisture-flux-convergence/10667#10667&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using this method, the following lines written in Python calculate the advection of temperature (TAdv):&lt;/p&gt;&#xA;&#xA;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;dy=111000 # [m]&#xA;lonres=lon[1]-lon[0] # constant&#xA;tadv=np.zeros(np.shape(T)); tadv.fill(np.nan)&#xA;for t in range(np.shape(T)[0]):&#xA;    for x in np.arange(1,len(lon)-1):&#xA;        for y in np.arange(1,len(lat)-1):&#xA;            dx = abs(111000*np.cos(lat[y]*(2*np.pi/360))*lonres)&#xA;            tadv[t,y,x] = -(u[t,y,x]*(T[t,y,x+1]-T[t,y,x-1])/(2*dx) +\&#xA;                              v[t,y,x]*(T[t,y+1,x]-T[t,y-1,x])/(2*dy))&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;I would expect a similar result from scaling the wind components by the temperature, at each grid cell, which is done as follows:&lt;/p&gt;&#xA;&#xA;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;ut  = np.zeros(np.shape(T))&#xA;vt  = np.zeros(np.shape(T))&#xA;UT  = np.zeros(np.shape(T))&#xA;for t in range(np.shape(T)[0]):&#xA;    for x in range(len(lon)):&#xA;        for y in range(len(lat)):&#xA;            ut[t,y,x] = u[t,y,x]*abs(T[t,y,x])&#xA;            vt[t,y,x] = v[t,y,x]*abs(T[t,y,x])&#xA;            UT[t,y,x] = ((ut[t,y,x]**2 + vt[t,y,x]**2)**0.5)*np.sign(T[t,y,x])&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The magnitude of the scaled wind vectors (UT) would be then similar to this &quot;amount of transport of T&quot;. It is multiplied by the sign of T (-1 or 1), because T are anomalies (there is T&amp;lt;0), in order to keep its the sign.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the results are totally different. What I am missing here? Is it a mistake in this assumption (that both results should look fairly similar)? Or is it a coding problem?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the figure below, I show the original T, u and v fields (left), and the results of the two above calculations: Tadv with u and v (middle), and the magnitude of the scaled vectors, UT, with the scaled vectors themselves uT and vT (right). TAdv is multiplied by 24*3600, so that the units are K/day. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VxJpt.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VxJpt.png&quot; alt=&quot;figure&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a link to a Dropbox folder, where the full script and sample data are available for download: &lt;a href=&quot;https://www.dropbox.com/sh/kcrb08h72jjj3rn/AAAIAUgKVrRrICAQtXhOHS2ta?dl=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.dropbox.com/sh/kcrb08h72jjj3rn/AAAIAUgKVrRrICAQtXhOHS2ta?dl=0&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8396" LastEditorUserId="8396" LastEditDate="2019-03-22T13:14:05.437" LastActivityDate="2019-12-17T19:02:07.923" Title="Temperature Advection using finite differences with gridded data" Tags="|meteorology|temperature|wind|numerical-modelling|atmospheric-circulation|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16528" PostTypeId="1" CreationDate="2019-03-20T17:08:59.940" Score="1" ViewCount="102037" Body="&lt;p&gt;What place in the world has the farthest time zone? I heard it was Kiribati but then I found that Apia (Samoa) is further. So, is there anyplace that is the farthest in time than these two? What about Solomon Islands?&lt;/p&gt;&#xA;" OwnerUserId="15480" LastEditorUserId="11908" LastEditDate="2019-03-21T20:04:13.097" LastActivityDate="2019-03-21T20:04:13.097" Title="What are the farthest Time Zone locations?" Tags="|meteorology|geology|climate-change|geography|time|" AnswerCount="2" CommentCount="2" ClosedDate="2019-03-22T00:42:08.697" ContentLicense="CC BY-SA 4.0" />
  <row Id="16529" PostTypeId="2" ParentId="16528" CreationDate="2019-03-20T18:14:03.830" Score="1" Body="&lt;p&gt;Given you are in the UK, ignoring daylight savings, &lt;a href=&quot;https://www.timetemperature.com/time-zone-maps/large-world-time-zone-map.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tonga and Tokelau&lt;/a&gt; are in time zones that are 13 hours ahead of the UK (i.e. to the east). To the west, the largest difference in time is 10 hours behind the UK, for Hawaii, Cook Islands &amp;amp; the Aleutian Islands.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="11908" LastEditDate="2019-03-21T00:56:26.203" LastActivityDate="2019-03-21T00:56:26.203" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16530" PostTypeId="2" ParentId="16438" CreationDate="2019-03-20T18:27:47.557" Score="2" Body="&lt;p&gt;Most likely.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I say that because it is heavily supposed that Mars, which is now tectonically stable, was active in the past. The reason why it has reached equilibrium is still a matter of discussion, and its tectonic history is merely hypothetical. But right away I'd say that the reason why Earth's tectonic activity could end converges on the reason why Mars, possibly, is stable nowadays: lack of internal energy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You see, the current geological model that explains the movement of the tectonic plates is based in mantle convection. The mantle is strictly solid, but on a large timespan, i.e., on the geological scale, it behaves as a fluid, which (sort of) means it has enough mobility to move, and therefore for convection to happen. But here's the catch - convection is a form of heat transfer. So we can interpret that convection, and therefore plate tectonics, are but a form of heat to be &quot;expelled&quot; from the inside to the outside. And naturally, at some point energy should end. But at which point? In my opinion, for an astoundingly long time (over 1 billion, and perhaps even 10 billion years). Earth's been spitting energy for almost 4 billion years now (before that, it was actually gathering energy through the kinetic energy from the impact of planetesimals, which can be thought of as huge meteorites) and it still has enough energy to heat the inner core to over 4000 Celsius degrees (that temperature is due to pressure &amp;amp; Earth's remaining energy, though).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is important to note that maybe due to the fact extreme depth is intrinsically associated with increased temperature, that pressure-driven temperature might suffice to generate mantle convection. But we wouldn't have oceanic crust generation (no inner heat - no partial melting next to mid ocean ridges - no oceanic crust generation), or it would be very limited. And besides, Earth is an open system with the universe, so it loses energy, and eventually it has to run out of it.&lt;/p&gt;&#xA;" OwnerUserId="13211" LastActivityDate="2019-03-20T18:27:47.557" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16531" PostTypeId="2" ParentId="16527" CreationDate="2019-03-20T18:36:04.330" Score="1" Body="&lt;p&gt;So i don't know for how many timesteps you've integrated. And I don't really understand what you have done to obtain the temperature &lt;span class=&quot;math-container&quot;&gt;$\rm T[t,s,y,x]$&lt;/span&gt; in your second box, but this seems a bit like a redundant operation: the end result is &lt;span class=&quot;math-container&quot;&gt;$T:=T$&lt;/span&gt;, so of course your right side looks like the left side, in terms of the temperature colourmap. I don't understand where the different scaling comes from though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your first numerical recipe is a whole different beast:&#xA;Approximating a differential in a first order symmetric fashion as &lt;span class=&quot;math-container&quot;&gt;$dT/dx \approx (T[t,y,x+1]-T[t,y,x-1])/(2*dx) $&lt;/span&gt; is known to be numerically unstable. This is why when you want to stick to finite differences, one uses &lt;a href=&quot;https://en.wikipedia.org/wiki/Upwind_scheme&quot; rel=&quot;nofollow noreferrer&quot;&gt;upwinding&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also your finite differences are cartesian ones, while you project them on a sphere, so to get physically correct results, you need to take the correct differentials in spherical coordinates into account.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2019-03-20T18:36:04.330" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="16532" PostTypeId="2" ParentId="16368" CreationDate="2019-03-20T18:52:42.273" Score="3" Body="&lt;p&gt;If &quot;oblique square prism&quot; is &lt;a href=&quot;https://d2vlcm61l7u1fs.cloudfront.net/media%2Fcb7%2Fcb72390f-ce0e-438f-a858-f85eae3650c3%2FphpSaZEAD.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;, where the top and bottom planes are parallel, then yes, there are. Carbonates (members of the Calcite and Dolomite, but not Aragonite, groups) have perfect cleavages that leave them with such habit. But be warned that they do not crystallize with such habit, it is a product of an effort that forced it to break accordingly to its cleavages.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vvPJl.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vvPJl.png&quot; alt=&quot;A beautifully euhedral calcite crystal.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A beautifully euhedral calcite crystal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If, however, you're looking for a mineral which crystallizes in such shape, then the answer is no. There are 14 &lt;strong&gt;Bravais lattices&lt;/strong&gt; (to put it simply, a Bravais lattice is the atomic arrangement that makes the smallest unit of a crystal, and so a crystal is a repetition of it). Each vary on edge ('line') length and angular relationship and obey some rules which are irrelevant for this discussion. The point is, none of the Bravais lattices has the edge parameters a, b and c (thickness/depth, width and height edges, respectively) in equal sizes (i.e. a = b = c) &lt;strong&gt;and&lt;/strong&gt; angles different than 90 degrees between them. Which means that no crystal will ever be fundamentally crystallized in such a form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mBIJM.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mBIJM.png&quot; alt=&quot;The 14 Bravais lattices. Any solid must obrigatorily crystallize in one of these 14 lattices. It&amp;#39;s a natural rule.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The 14 Bravais lattices. Any solid must obrigatorily crystallize in one of these 14 lattices. It's a natural rule.&lt;/p&gt;&#xA;" OwnerUserId="13211" LastActivityDate="2019-03-20T18:52:42.273" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16534" PostTypeId="2" ParentId="15983" CreationDate="2019-03-20T19:32:25.273" Score="1" Body="&lt;p&gt;Not really.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming even minor igneous bodies differentiate (stocks), and that differentiation is basically a process of decantation of the solid magmatic phase (a process known as fractional crystalization) and &lt;a href=&quot;https://en.wikipedia.org/wiki/Fractionation&quot; rel=&quot;nofollow noreferrer&quot;&gt;fractionation&lt;/a&gt; of the fluid magmatic phase, virtually any solid mixture can differentiate. If you're not convinced, here's another argument.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's take an analogous situation to differentiation: exsolution. They're not the same. Exsolution involves ionic migration in a solid structure. Differentiation involves ionic migration in a fluid (magma), which lacks structure. But both involve an outcome of different chemical phases. And exsolution can happen in microscopic sizes of milimetric crystals. So its fluid-ambient counterpart would, as a logical conclusion, be also able to happen on such minute conditions, and perhaps on smaller even.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And I'm not sure what you mean that differentiation will never end? On a long term geological scale - I'm talking about hundreds of millions to billions of years - that idea is perhaps correct, assuming the upper mantle and crust are constantly changing their compositions. But if you're saying that differentiation is a process that happens widespread (the entire crust, or the entire planet), rather than on specific locations (where partial melting occurs), under a small timescale (millions of years), then you're not correct, because differentiation only occurs in mixtured &lt;strong&gt;fluids&lt;/strong&gt; (and I'm not sure whether it's used for any other fluid than magma).&lt;/p&gt;&#xA;" OwnerUserId="13211" LastActivityDate="2019-03-20T19:32:25.273" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16536" PostTypeId="2" ParentId="16522" CreationDate="2019-03-20T20:30:29.950" Score="8" Body="&lt;p&gt;This is an interesting and common question, so I'll try to give a good answer here, that I think is a good place, as well as GIS and Open Data SE.&#xA;First, regarding the format, you will never find data natively stored in text or tabular form, because the large data volume would lead to huge files very difficult to handle. Data is usually stored in binary files, common standards are .hgt and .tif. And there are many software and utilities that can export small subsets of the data into text, csv, or tabular formats.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll list here the global or near to global sources. All of them have advantages and disadvantages, and all have data gaps and artifacts, specially in areas with rough topography. So depending of your area of interest, one or the other can be better.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;&lt;a href=&quot;https://www2.jpl.nasa.gov/srtm/&quot; rel=&quot;nofollow noreferrer&quot;&gt;SRTM (Shuttle Radar Topographic Mission)&lt;/a&gt;&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Resolution: 1 arc-sec (~30 m)&lt;br&gt;&#xA;Data epoch: February 11&lt;span class=&quot;math-container&quot;&gt;$^{th}$&lt;/span&gt; to 22&lt;span class=&quot;math-container&quot;&gt;$^{nd}$&lt;/span&gt; 2000&#xA;Data type: Integer&#xA;Vertical reference: Orthometric (geoidal)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most widely used standard, due to its quality, resolution, and coverage. It covers the whole globe between latitudes 60°N and 56°S.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/53EdU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/53EdU.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In contrast to all other datasets, all the data was acquired in a 11-day mission, therefore, it have unmatched consistency, specially in areas with rapid terrain changes like glaciers, open pit mines, cities, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The space shuttle was carrying two radars that created two independent terrain models, the coverage above corresponds to the SAR-C instrument that produced the data that is most widely used. The second instrument was the X-SAR, that had a narrower swath, and does not have global coverage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are multiple versions of these datasets:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;SRTM v3&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The latest official release is version 3. It comes in its original form, that includes data gaps and a gap-filled version, on which those gaps have been filled with data coming from multiple sources (but primarily ASTER GDEM).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data can be accessed through multiple gateways, some of them are:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthexplorer.usgs.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS EarthExplorer&lt;/a&gt;&lt;br&gt;&#xA;&lt;a href=&quot;https://search.earthdata.nasa.gov/search&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA EarthData&lt;/a&gt;&lt;br&gt;&#xA;&lt;a href=&quot;https://gdex.cr.usgs.gov/gdex/&quot; rel=&quot;nofollow noreferrer&quot;&gt;LP DAAC Global Data Explorer&lt;/a&gt;&#xA;&lt;a href=&quot;https://dds.cr.usgs.gov/srtm/version2_1/SRTM1/&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS data server&lt;/a&gt; (Version 2.1)&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;CGIAR SRTM&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An independent post-processing of SRTM data.  Known also as SRTM v4.  It consists of a gap-filled version of SRTM using an &lt;a href=&quot;http://srtm.csi.cgiar.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;advanced algorithm&lt;/a&gt;. It is only available at 3 arcsec resolution (90 meters) . It can be downloaded at the &lt;a href=&quot;http://srtm.csi.cgiar.org/srtmdata/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CGIAR SRTM Download manager&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;NASADEM&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The SRTM data was reprocessed with cutting edge technology, improving accuracy and reducing data gaps. In contrast to other SRTM versions, it offers also a ellipsoidal version of the data (instead of geoidal), and the data comes in floating point values (instead of integers). NASADEM is expected to be the last official release of SRTM data. This DEM is still in the development phase but should be released at any time. A provisional version has been released and can be downloaded at the &lt;a href=&quot;https://e4ftl01.cr.usgs.gov/provisional/MEaSUREs/NASADEM/&quot; rel=&quot;nofollow noreferrer&quot;&gt;MEaSUREs data repository&lt;/a&gt;. More information on how to use this data can be found in my answer &lt;a href=&quot;https://gis.stackexchange.com/a/267135/111934&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This dataset should NOT be confused with the &quot;NASA Shuttle Radar Topography Mission Global 1 arc second V003&quot; (SRTMGL1). Which corresponds to the SRTM v3 data described above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;ViewFinderPanoramas&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some individuals like Jonathan de Ferranti, tackled the gargantuan task of doing a manual quality assessments of all the gaps of the SRTM and areas that have erroneous data. To then fix it using many sources, including many national mapping agencies from around the world. He produced a great version of SRTM with most errors fixed. Unfortunately, all this work was done before the worldwide release of full resolution SRTM data in 2014, therefore, for most of the world this data have only 3 arc-sec resolution (~90 m). And it can be downloaded at &lt;a href=&quot;http://viewfinderpanoramas.org/dem3.html#andes&quot; rel=&quot;nofollow noreferrer&quot;&gt;ViewFinderPanoramas.org&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;SRTM X-SAR&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Data from the second radar on board the Endevour space shuttle during the SRTM mission. It has slightly higher resolution (~20 m) but worst coverage, because the multiple swaths did not overlap, so for example, over North America the coverage looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yqKFm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yqKFm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This data can be downloaded from &lt;a href=&quot;https://download.geoservice.dlr.de/SRTM_XSAR/&quot; rel=&quot;nofollow noreferrer&quot;&gt;DLR Geoservice&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;&lt;a href=&quot;https://asterweb.jpl.nasa.gov/gdem.asp&quot; rel=&quot;nofollow noreferrer&quot;&gt;ASTER GDEM&lt;/a&gt;&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Resolution: 1 arc-sec (~30 m)&lt;br&gt;&#xA;Data epoch: 2000 to 2011&#xA;Data type: Integer&#xA;Vertical reference: Orthometric (geoidal)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With almost complete coverage between 83°N and 83°S, GDEM was produced from more 1.5 million stereo pair images by ASTER sensor. A joint project between JAXA and NASA on board of Terra satellite. This is the coverage of the latest release:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FJ9PY.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FJ9PY.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The current version is GDEM v3 (released on August 5 2019). This Release also includes the ASTER Water Body Dataset (ASTWBD), a valuable dataset to correct terrain models. GDEM v3 is available from:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://search.earthdata.nasa.gov/search&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA EarthData&lt;/a&gt;&lt;br&gt;&#xA;&lt;a href=&quot;https://gdemdl.aster.jspacesystems.or.jp/index_en.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Japan Space Systems&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;&lt;a href=&quot;https://www.eorc.jaxa.jp/ALOS/en/aw3d30/index.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;ALOS World 3D&lt;/a&gt;&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Resolution: 5m (paid), 30 m (free)&lt;br&gt;&#xA;Data epoch:  2006 to 2011&#xA;Data type: Integer&#xA;Vertical reference: Orthometric (geoidal)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Somehow the successor of ASTER, ALOS and its instrument PRISM, also offer stereo capability and higher resolution. And it was used to generate a new DEM with near global coverage:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MpTXd.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MpTXd.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The free 30 m resolution version of the data (with maximum resolution of 5 m), can be downloaded at &lt;a href=&quot;https://www.eorc.jaxa.jp/ALOS/en/aw3d30/data/index.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;JAXA AW3D30 DSM data page&lt;/a&gt; (need to sign up first). Current version is AW3D30 v2.2 (released in April 2019).&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;&lt;a href=&quot;https://europepmc.org/article/PPR/PPR82041&quot; rel=&quot;nofollow noreferrer&quot;&gt;GSDEM30&lt;/a&gt;&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The &quot;Global Seamless DEM 30&quot; is a 1-arcsec (~30 m) DEM that was constructed by merging unfilled SRTM, ALOS World 3D, and ASTER GDEM v2 datasets. By combining all these sources, it reduces data-gaps and significantly improves the quality of the data in regions where any of the base DEMs performs poorly. Data can be downloaded from the Wuhan University's &lt;a href=&quot;http://sendimage.whu.edu.cn/res/DEM_share/GSDEM30/&quot; rel=&quot;nofollow noreferrer&quot;&gt;SENDIMAGE servers&lt;/a&gt;. More details of the data merging process can be found in &lt;a href=&quot;https://doi.org/10.20944/preprints201906.0036.v1&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;&lt;a href=&quot;https://www.dlr.de/dlr/en/desktopdefault.aspx/tabid-10261/371_read-19509/#/gallery/24516&quot; rel=&quot;nofollow noreferrer&quot;&gt;TanDEM-X WorldDEM&lt;/a&gt;&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Resolution: 12m (paid), 90 m (free)&lt;br&gt;&#xA;Data epoch:  2010 to 2015&#xA;Data type: Floating point&#xA;Vertical reference: Ellipsoidal&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The latest radar base global elevation model, created from two satellites orbiting in tandem formation (TanDEM-X), allowing high accuracy single-pass InSAR and DEM generation with truly global coverage. The free 90 meter resolution data can be downloaded from &lt;a href=&quot;https://download.geoservice.dlr.de/TDM90/&quot; rel=&quot;nofollow noreferrer&quot;&gt;DLR Geoservice&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;&lt;a href=&quot;https://www.pgc.umn.edu/data/arcticdem/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ArticDEM and REMA&lt;/a&gt;&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Resolution: 2m&lt;br&gt;&#xA;Data epoch:  2007 to 2018&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This two projects turned the polar areas from being the ones with the worst available topographic data to the ones with the best data. By computing DEM's from millions of stereo image pairs from the high-resolution imaging satellites of DigitalGlobe. ArticDEM covers all latitudes north of 60°N:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9oCvp.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9oCvp.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And REMA covers all latitudes south of 60°S:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/W5HHR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/W5HHR.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data can be explored and downloaded from the &lt;a href=&quot;https://livingatlas2.arcgis.com/arcticdemexplorer/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ArcticDEM Exporer&lt;/a&gt;, and &lt;a href=&quot;https://livingatlas2.arcgis.com/antarcticdemexplorer/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Antarctic REMA Explorer&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2020-01-19T04:45:34.030" LastActivityDate="2020-01-19T04:45:34.030" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16537" PostTypeId="2" ParentId="16519" CreationDate="2019-03-20T20:53:00.837" Score="1" Body="&lt;p&gt;Archive, reanalysis and forecast data of those variables worldwide from GFS model can be accessed at &lt;a href=&quot;https://www.ready.noaa.gov/READYcmet.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA Ready&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is an example of those variables in the forecast for a given location:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/uWIrS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uWIrS.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And if you click the &quot;Text Result&quot; ling before the meteorogram you can access a tab-delimited text file that looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jHSXw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jHSXw.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-03-20T20:53:00.837" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16538" PostTypeId="2" ParentId="16528" CreationDate="2019-03-20T23:51:03.217" Score="6" Body="&lt;p&gt;The original wording of your question revealed that you are missing something about what time zones are, and how they are defined. So let me start from the begin. If you are impatient, you can jump forward for the answer in bold font after the figure, and come back here for the explanation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Time zones are defined by by man just to facilitate time keeping. In principle the idea is that time anywhere should be such that noon happens when the Sun reaches its maximum elevation over the horizon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Time keeping wasn't easy in the past. Therefore, time was kept by astronomical observatories. And due to the extent of the British Empire, in history was the observatory at Greenwich the one that stayed as the global reference point for time and longitude (because at first the main utility of precise time was to compute precise longitudes).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As Earth's rotates 360° in 24 hours, that's 15° per hours. So if you know the longitude of a place, you just divide that longitude by 15 and you know how many hours you have to add/subtract from Greenwich reference time to get your local time. For example: If you are in Eastern Island at longitude 109°W, it means your local time will be the time at Greenwich (know as Universal Time or UT) minus 7 hours 16 minutes (&lt;span class=&quot;math-container&quot;&gt;$109/15=7.26\, h = 7h\, 16m$&lt;/span&gt;), if you use that time, the Sun will effectively be at its highest point at 12:00 h.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But as you can see, if you move in the east-west direction, every point would have a different time if we just use the above rule, which is very inconvenient, as the time in the east side of a city would be different than the time on the west side.&#xA;For this reason they invented Time Zones: to keep the same time within reasonable large areas. In principle they created time zones every 15°, so that no point would be more than 30 minutes off their solar time. In other words, the moment the Sun reaches its maximum elevation in the sky won't be more than 30 minutes off from clock's noon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this time zone lines crossed political borders, so they were adapted and bent so that whole countries or at lest states remained within a single time zone. That way the current designation of time zones was established and is neatly summarized in &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:World_Time_Zones_Map.png&quot; rel=&quot;noreferrer&quot;&gt;this figure from Wikipedia commons&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/erPyI.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/erPyI.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see that &lt;strong&gt;the most extreme time zones are +14 hours at &lt;a href=&quot;https://en.wikipedia.org/wiki/Line_Islands&quot; rel=&quot;noreferrer&quot;&gt;Line Islands&lt;/a&gt; (Kiribati), and -12 hours in and around Baker Islands (US)&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, &lt;strong&gt;the maximum possible difference between times on Earth is 26 hours&lt;/strong&gt;. That means that at 11:00 PM of a Monday in Baker Island, it is 1:00 AM of a Wednesday in Line Islands.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As both places are fairly close to the equator, I doubt they use daylight saving. Therefore, that would be the maximum. In the case of Apia in Samoa, it also uses +14 hours but only in summer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are mostly concern to the time difference with the UK, the largest would be +14 hours to Line Islands.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, take into account that time zones are politically defined, so at any time a political decisión can change the actual answer to this question.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-03-21T00:59:13.267" LastActivityDate="2019-03-21T00:59:13.267" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16539" PostTypeId="2" ParentId="16527" CreationDate="2019-03-21T00:44:51.147" Score="3" Body="&lt;p&gt;When I look at problems like these I first check to see if there is a well tested and well documented implementation already rather than reinventing the wheel.  In this case &lt;a href=&quot;https://unidata.github.io/python-gallery/examples/850hPa_Temperature_Advection.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;MetPy temperature advection&lt;/a&gt; is a well tested software that does many of the things meteorologists want including calculating finite differences with the right map scale factors. Since you are using Python I would at least look at their implementation first and correct your code even if you are not going to use their code. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please do this first and validate your data before you attempt any downscaling operation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And finally AtmosphericPrisonEscape is correct. If you are using lat,lon grid and calculating finite differences you need to include map scale factors. And if you are using global grids the finite differences will not work at the poles. If you are using regional grids that is not a problem. Please include as much  detail as possible when you ask a computational question. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-03-21T02:24:39.043" LastActivityDate="2019-03-21T02:24:39.043" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16542" PostTypeId="2" ParentId="12013" CreationDate="2019-03-21T09:36:20.390" Score="0" Body="&lt;p&gt;Saprolite include regolith plus humus ie soil particles in combination with &#xA;dead plant and animal matter whereas regolith is just course material from weathered rock parent material.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Saprolite is common in humid climatic regions whilst regolith is common in arid ans semi arid climatic conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Saprolite is polyminerallic and  regolith is monominerallic.&lt;/p&gt;&#xA;" OwnerUserId="15486" LastActivityDate="2019-03-21T09:36:20.390" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16547" PostTypeId="1" CreationDate="2019-03-22T04:05:06.733" Score="5" ViewCount="101" Body="&lt;p&gt;What proportion of the water in a cloud will 'rain out'?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or, comparing the cloud before and after it has rained, what proportion of the water is left afterwards?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I really have no idea so am just looking for an order of magnitude range, is it 50%, 1% or something tiny like 0.00001%?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: I wanted to leave the specifics to the answerer, but maybe an easier question is the difference in amount of water (any form) above the surface before and after rain.&lt;/p&gt;&#xA;" OwnerUserId="15491" LastEditorUserId="15491" LastEditDate="2019-03-24T22:38:19.180" LastActivityDate="2019-03-24T22:38:19.180" Title="Roughly what proportion of a cloud does 'rain out'?" Tags="|meteorology|clouds|rainfall|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16550" PostTypeId="1" CreationDate="2019-03-22T18:15:55.410" Score="5" ViewCount="144" Body="&lt;p&gt;I was reminded recently of a moment in the Eragon books where the main characters see a &quot;tall&quot; mountain range, and then after a minute realize that the white sky stretching up above them is just mountains too, covered in snow. Which got me wondering - if there was a mountain that reached to space, obviously there would be some point above which snow would not accumulate. Where would this be?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thoughts: I know most of the Earth's moisture is in the troposphere, so it seems reasonable to assume it would be confined to that region - but higher clouds like nacreous and noctilucent clouds are made of ice crystals, which could conceivably deposit on a mountain. Or would this be rare enough that it would sublimate faster than it could accumulate?&lt;/p&gt;&#xA;" OwnerUserId="14870" LastActivityDate="2021-04-20T20:36:51.020" Title="How high could snow form on a mountain?" Tags="|clouds|mountains|snow|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16551" PostTypeId="1" CreationDate="2019-03-22T19:12:42.107" Score="1" ViewCount="29" Body="&lt;p&gt;For glacier models, there exist alternatives to the Glen's power-law?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I searched on internet, but I have not found other alternatives.&lt;/p&gt;&#xA;" OwnerUserId="12582" LastActivityDate="2019-03-22T19:12:42.107" Title="Glen's power-law alternatives" Tags="|models|glaciology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16553" PostTypeId="1" AcceptedAnswerId="17307" CreationDate="2019-03-23T09:39:06.930" Score="1" ViewCount="153" Body="&lt;p&gt;I know the ridge at the South of Australia is named Southeast Indian Ridge. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to know if there is a geological name for the three subduction branches that cross indonesian zone, at the North of Australia, as seen in this map.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/waVU6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/waVU6.png&quot; alt=&quot;Current plate limits from USGS&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: &lt;a href=&quot;https://www.researchgate.net/figure/Figura-12-Placas-y-dorsales-oceanicas-USGS-US-Geological-Survey_fig2_320286510&quot; rel=&quot;nofollow noreferrer&quot;&gt;researchgate.net&lt;/a&gt; Map by &lt;a href=&quot;https://www.usgs.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;United States Geological Survey&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-03-23T10:05:40.377" LastActivityDate="2019-06-26T07:50:54.653" Title="Is there a name for subduction boundaries at the North of Australia?" Tags="|geology|plate-tectonics|subduction|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16556" PostTypeId="1" AcceptedAnswerId="16558" CreationDate="2019-03-23T19:36:16.713" Score="14" ViewCount="24059" Body="&lt;p&gt;Most explanations for high tides say high tides come from water being attracted by the moon (2/3) and the sun (1/3). Attraction occurring in the direction of the moon is visible on the side close to the moon below:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WPbGj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WPbGj.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;sup&gt;Source: &lt;a href=&quot;https://earthscience.stackexchange.com/q/8221/15501&quot;&gt;This question&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;However why does water also move away on the opposite side of the Earth?&lt;/p&gt;&#xA;&lt;p&gt;And moreover, why does this high tide on the opposite side also occur when the Moon and Sun are in conjunction and therefore nothing can attract water on the far side?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vpcBJ.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vpcBJ.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;sup&gt;&lt;a href=&quot;https://www.eg.bucknell.edu/physics/astronomy/astr101/specials/tides.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="15501" LastEditorUserId="6467" LastEditDate="2022-12-05T23:34:34.577" LastActivityDate="2022-12-05T23:34:34.577" Title="Why do high tides occur simultaneously on opposite sides of the Earth?" Tags="|tides|astronomy|" AnswerCount="2" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16557" PostTypeId="2" ParentId="16556" CreationDate="2019-03-23T20:22:12.177" Score="9" Body="&lt;p&gt;Tides arise from the differences in gravitational pull across an object. That's why their strength falls as &lt;span class=&quot;math-container&quot;&gt;$r^3$&lt;/span&gt; instead of &lt;span class=&quot;math-container&quot;&gt;$r^2$&lt;/span&gt; (where &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; is the distance between the two objects).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Visually it can be understood as follows&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oud9P.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oud9P.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does that makes sense?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The key is to consider the differences in gravitational pull felt by the Solid Earth and both the water facing the Moon, and that oposite to it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the Earth and the oceans orbit around the Earth-Moon center of mass, the Earth will make a tighter circle than the ocean in the &quot;far side&quot; because it feels a stronger pull from the Moon. As a consequence, the ocean will lag behind and will bulge as in the figure.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-03-24T01:10:05.297" LastActivityDate="2019-03-24T01:10:05.297" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16558" PostTypeId="2" ParentId="16556" CreationDate="2019-03-24T14:47:28.357" Score="16" Body="&lt;p&gt;First of all, tides are not as simple as the &amp;quot;two-bulge&amp;quot; simplification. In reality, the diagram shown is misleading. The two bulges appear assuming an ocean of constant depth covers the entire surface of Earth. Clearly that is not the case and in the diagram you can see the continents. Considering the different sizes of the basins and the distinct frictional characteristics in each location, the resulting tidal effect is much more complex. The difference in phase and amplitude is shown here and it clearly shows that the the tide varies for the same longitude. That wouldn't be the case in the simple explanation above.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/WaeYt.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WaeYt.jpg&quot; alt=&quot;M2 tide&quot; /&gt;&lt;/a&gt;&#xA;Source &lt;a href=&quot;https://en.wikipedia.org/wiki/File%3AM2_tidal_constituent.jpg&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Looking at this tidal animation from &lt;a href=&quot;http://volkov.oce.orst.edu/tides/&quot; rel=&quot;noreferrer&quot;&gt;TPXO&lt;/a&gt; is also illustrative.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/zth2j.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zth2j.gif&quot; alt=&quot;Tidal animation&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The simple &amp;quot;two-buldge&amp;quot; explanation would result in a pure two peak daily tide. That is certainly not the case in places like the Gulf of Mexico.&lt;/p&gt;&#xA;&lt;p&gt;As mentioned in Camilo Rada's answer, the bulges are a consequence of the tidal force. This  apparent force result from the difference in strength in the gravitational field. The result is that Earth's body is stretched toward and away from the center of mass of the Earth-Moon system. The water thus adjust to this difference in geopotential giving rise to the tides.&lt;/p&gt;&#xA;&lt;p&gt;A more intuitive explanation is given in &lt;a href=&quot;https://www.nsta.org/store/product_detail.aspx?id=10.2505/9781936959020&quot; rel=&quot;noreferrer&quot;&gt;Project Earth Science: Physical Oceanography&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The explanation of the two-bulge tide comes from the fact that the Moon and Earth form a two-body system that rotates about an axis located within Earth.&lt;/p&gt;&#xA;&lt;p&gt;The bulge of water on the side of Earth that faces the Moon is easily explained. It is due to the gravitational attraction between the Moon and Earth, including the water on Earth. This attraction pulls water toward the Moon and creates a “bulge” on the surface of Earth. The bulge on the other side of Earth is due to inertia. Inertia is the tendency of an object at rest to stay at rest and the tendency of a body in motion to continue its motion in a straight line.&lt;/p&gt;&#xA;&lt;p&gt;There is an inertial tendency resulting from the rotation of the Earth-Moon system for objects (water among them) to move away from both sides of Earth—the side facing toward the Moon and the side facing away. The model demonstrates that the effect of things moving away from Earth is much greater on the side facing away from the Moon.&lt;/p&gt;&#xA;&lt;p&gt;Many textbooks and other sources use the concept of “centrifugal force”— which is actually a preconception—to explain the effects of inertia. According to this preconception, there is a force that acts on all objects that are in circular motion, and this force pushes or pulls the object out from the circle. There is no such force. The preconception arises from our own experience with circular motion.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The gravitational forces of Earth, Sun and Moon cause a bulge of water on the nearest side and an equal bulge on the other side. Thus, in this simple scenario, the tide is composed of two bulges of water (four, in fact), traveling around the world as the world spins. When Moon and Sun aligned, their respective bulges add together to form &amp;quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Tide#Range_variation:_springs_and_neaps&quot; rel=&quot;noreferrer&quot;&gt;spring tides&lt;/a&gt;&amp;quot; every two weeks. When the Moon and Sun are at right angles, we encounter &amp;quot;neap tides&amp;quot;, as the bulge of the sun adds to the low lunar tide, resulting in higher low tides but lower high tides.&lt;/p&gt;&#xA;&lt;p&gt;The limitations of this model are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;It cannot explain that there are places without tides, with one daily high, and most with two tidal highs each day.&lt;/li&gt;&#xA;&lt;li&gt;Tidal height is not maximal at the Equator (and minimal at the poles) as the simplification suggests.&lt;/li&gt;&#xA;&lt;li&gt;High tide is not associated with the position of the Moon. It occurs at different times of the lunar cycle depending on the location.&lt;/li&gt;&#xA;&lt;li&gt;If continents are included, the tidal wave would reflect off the continental shelf as it reaches a continent. A tidal wave of almost equal magnitude will be propagating in the opposite direction, which is not observed.&lt;/li&gt;&#xA;&lt;li&gt;The tidal waves required for this model would have to travel at much faster speeds that are possible in reality.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;In reality, the tides instead of running east to west as Earth rotates, tidal waves propagate around in circles around islands, and certain points in the sea, called tidal nodes or &lt;a href=&quot;https://en.wikipedia.org/wiki/Amphidromic_point&quot; rel=&quot;noreferrer&quot;&gt;amphidromic points&lt;/a&gt;. These nodes can be seen in the first figure from this answer.&lt;/p&gt;&#xA;&lt;p&gt;Thus, the tidal patterns in the ocean are a set of rotating standing waves. These waves have periods that represent the natural resonance periods of the ocean basins. These waves can be considered modes of &amp;quot;vibration&amp;quot; and can be decomposed using a Fourier decomposition. That is the source of the different &lt;a href=&quot;https://en.wikipedia.org/wiki/Tide#Tidal_constituents&quot; rel=&quot;noreferrer&quot;&gt;tidal constituents&lt;/a&gt; that are used currently for tidal prediction.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-03-24T14:47:28.357" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16560" PostTypeId="1" AcceptedAnswerId="16569" CreationDate="2019-03-24T17:24:26.373" Score="7" ViewCount="747" Body="&lt;p&gt;I want to calculate the maximum power angle of photovoltaics depending of the coordinates on Earth. That means at which angle I should align my solar panel to get the maximum power over the year?&#xA;I think to get the maximum power I should point the solar panel to the South. But at which angle I should align the solar panel? &#xA;Is it always south? When I am in australia then I should align the solar panel to the north? Or I am wrong? &lt;/p&gt;&#xA;" OwnerUserId="15506" LastEditorUserId="11908" LastEditDate="2019-03-25T00:09:40.777" LastActivityDate="2023-03-06T09:19:55.370" Title="Calculate the maximum power angle of a solar panel (photovoltaics)" Tags="|climate|sun|solar-terrestrial-physics|astronomy|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16561" PostTypeId="2" ParentId="11984" CreationDate="2019-03-24T17:32:29.393" Score="2" Body="&lt;p&gt;They don't really share a plate, now they did for a long time and the boundary between them is rather recent but they are separate plates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;BUT this was only discovered recently, &lt;a href=&quot;https://phys.org/news/2012-09-sumatra-quake-crustal-plate-breakup.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;recently&lt;/a&gt; as in &lt;a href=&quot;https://www.nature.com/articles/nature11520&quot; rel=&quot;nofollow noreferrer&quot;&gt;2012&lt;/a&gt;, so older references treat them as the same plate.  The &quot;indo&quot; in indo-australian plate is being dropped from more modern references. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Zk5Nj.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Zk5Nj.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The two plates are moving in almost the exact same direction and speed, so it is easy to see why it took so long to be discovered. Almost is also the key, the forces separating them up is rather weak, tectonically speaking, without a lot of heavy volcanics so the separation is very slow. Now they were not tightly connected to begin with, so there is no continental fault between them. Spreading centers &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/A9pBx.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/A9pBx.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2019-03-24T17:42:44.343" LastActivityDate="2019-03-24T17:42:44.343" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16562" PostTypeId="1" AcceptedAnswerId="16566" CreationDate="2019-03-24T17:38:40.127" Score="3" ViewCount="2942" Body="&lt;p&gt;I see both terms refereing to fractures on crystals or minerals, so I wonder if they could be considered synonymous.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If no, what's the difference between both terms?&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-03-25T09:07:55.677" LastActivityDate="2019-03-25T09:07:55.677" Title="What's the difference between cleavage and fracture?" Tags="|rocks|mineralogy|minerals|crystals|crystallography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16566" PostTypeId="2" ParentId="16562" CreationDate="2019-03-24T22:47:23.423" Score="4" Body="&lt;p&gt;They are not synonymous. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cleavage means breaking along planes defined by crystallographic directions. For example, cubic crystals like halite, NaCl, often cleave along directions that follow the cubic form. However, with a different bond strength, like fluorite &lt;span class=&quot;math-container&quot;&gt;$\ce{CaF2}$&lt;/span&gt;, the crystals cleave most easily along octahedral directions, similar to two pyramids sharing a base.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fracture is when the break does not form along the crystallographic directions. It then can be grainy or conchoidal (like breaking glass). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fracture is also used to describe the breaking of rocks as opposed to single crystals. In this case planar fracture follows the direction of forces that formed the rock.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastEditorUserId="11908" LastEditDate="2019-03-25T04:26:48.427" LastActivityDate="2019-03-25T04:26:48.427" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16569" PostTypeId="2" ParentId="16560" CreationDate="2019-03-24T23:52:26.893" Score="7" Body="&lt;p&gt;This question can be answered in many different ways that take into account, or ignore, the many factors that affect the total output of a fix solar panel over a year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, all answers will agree that the solar panel will have to &lt;strong&gt;face the north in the southern hemisphere&lt;/strong&gt;, and the south in the northern hemisphere. This is because that is the direction where the Sun will be when it reaches the maximum elevation during the day. Or if you are within the tropics (&lt;span class=&quot;math-container&quot;&gt;$\pm$&lt;/span&gt;23.5° of latitude), that's the direction where the Sun will be &lt;strong&gt;most of the days&lt;/strong&gt; when it reaches the maximum elevation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The tricky part is the inclination angle, because the solar elevation changes trough the day, and the maximum elevation changes trough the year. In general, the mean elevation at solar noon (that usually do not match the clocks noon due to standardized time zones), is given by:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\overline{h_{max}}=90^o-\text{Latitude}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And through the year it will vary &lt;span class=&quot;math-container&quot;&gt;$\pm$&lt;/span&gt;23.5°.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in a first zero-order approach you can just use that mean value. Now, to find the optimum value you have to model the Sun's position trough the year and run a complex calculation to find the angle that maximizes output. Thankfully some people have done that, and they have reduced the output to simple empirical formulas. For example, in &lt;a href=&quot;https://www.solarpaneltilt.com/&quot; rel=&quot;noreferrer&quot;&gt;solarpaneltilt.com&lt;/a&gt; they provide the following formulas:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\text{Optimim angle}=\left\{ \begin{array}{rcl} \text{Latitude} \times 0.87 &amp;amp; \mbox{if} &amp;amp; \text{Latitude}&amp;lt;25^o \\ \text{Latitude} \times 0.76 + 3.1 &amp;amp; \mbox{if} &amp;amp; 25^o&amp;lt;\text{Latitude}&amp;lt;50^o\end{array}\right.$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And if you don't want to put the fingers in a calculator they provide a table with some values for different latitudes:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WXKxZ.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WXKxZ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this approach pinpoints to an angle with great accuracy, while neglecting what can be one of the main factors affecting the output of your solar panels: &lt;strong&gt;weather&lt;/strong&gt;. Therefore, the above approach would be very accurate if you live in a desert, but misleading if you are in an area with clear weather in winter and rainy weather in summer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To tackle this problem you can download weather statistics for your location and find the optimum angle yourself. Ideally you would do this by calculating solar output on each day, but I'll first show you also a simpler approach month by month that you can reproduce with very little computer skills and the results will be very similar.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The general workflow is as follows:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Find the typical solar radiation reaching the surface at your location each month/day of the year. Let's call this parameter &lt;span class=&quot;math-container&quot;&gt;$S$&lt;/span&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Find the typical solar elevation over the horizon at solar noon at your location each month/day of the year. Let's call this parameter &lt;span class=&quot;math-container&quot;&gt;$h$&lt;/span&gt;,&lt;/li&gt;&#xA;&lt;li&gt;Find the maximum solar power that a solar panel could receive if directly facing the Sun, let's call this &lt;span class=&quot;math-container&quot;&gt;$S_{max}$&lt;/span&gt; and it will be given by&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\hspace{12em} S_{max}=\frac{S}{\sin(h)}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;4&quot;&gt;&#xA;&lt;li&gt;Find the effective power hitting a solar panel at a set angle &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt;. Let's call this &lt;span class=&quot;math-container&quot;&gt;$S_{eff}$&lt;/span&gt; and it will be given by&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\hspace{12em} S_{eff}=S_{max} \cos(90^o-h-\theta)$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;5&quot;&gt;&#xA;&lt;li&gt;Adding &lt;span class=&quot;math-container&quot;&gt;$S_{eff}$&lt;/span&gt; for each month/day of the year. Let's call this &lt;span class=&quot;math-container&quot;&gt;$S_{total}$&lt;/span&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Put all these calculations in a spreadsheet and then play with different values of &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; until you find the one that produces the maximum &lt;span class=&quot;math-container&quot;&gt;$S_{total}$&lt;/span&gt;.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Now, to get the typical &lt;span class=&quot;math-container&quot;&gt;$S$&lt;/span&gt; values for each month you can go to the &lt;a href=&quot;https://climexp.knmi.nl/selectfield_rea.cgi&quot; rel=&quot;noreferrer&quot;&gt;KNMI Climate Explorer&lt;/a&gt;, click the option &quot;ERA-interim 1979-now&quot;, then select the variable &quot;surface net solar/longwave radiation&quot;, and click &quot;Select Filed&quot; on the top.&#xA;Then, you will see a bunch of options, but only focus on the first box:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gKN9a.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gKN9a.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fill, the coordinates, add half a degree around your location (this model resolution is ~ 80 km, so don't get picky with accurate locations), select the &quot;max&quot; option (mean would work too), and hit &quot;make time series&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You will get a time series of solar radiation in your area, and the average per month from 1979 to 2019, it will look like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rnmGM.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rnmGM.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, you click the &quot;raw data&quot; link above the plot and you will get the numbers for &lt;span class=&quot;math-container&quot;&gt;$S$&lt;/span&gt; to feed into your spread sheet, they are in the first data column:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3i3vc.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3i3vc.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For daily values you start from &lt;a href=&quot;https://climexp.knmi.nl/selectdailyfield2.cgi&quot; rel=&quot;noreferrer&quot;&gt;Daily fields&lt;/a&gt;, and select ERA-interim 1979-now &lt;strong&gt;rsds&lt;/strong&gt; field. From there is the same as before. And the plot will look like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TFEor.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TFEor.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, to get the solar elevation for each month you can use this &lt;a href=&quot;https://keisan.casio.com/exec/system/1224682331&quot; rel=&quot;noreferrer&quot;&gt;Solar elevation angle (for a year) Calculator&lt;/a&gt; and just take the day closer to the center of the month to feed it into your spredsheet. For getting angles for each day, you can use this &lt;a href=&quot;https://aa.usno.navy.mil/data/docs/mrst.php&quot; rel=&quot;noreferrer&quot;&gt;Rise/Set/Transit Times for Major Solar System Bodies calculator&lt;/a&gt;, this is how I filled the form for my area of interest:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0NWhP.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0NWhP.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that I choose a leap year so it matches the number of days in the output from the KNMI Climate Explorer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whith all this, the formulas above and a bit of spreadsheet skils you can find the optimal angle for your location.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My monthly spreadsheet looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/72z42.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/72z42.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And the daily one like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1ycGa.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1ycGa.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, for my area of interest the angles differ only by 1° between the monthly and daily calculation. And about 4° with the formulas from solarpaneltilt.com. However, in other climates the differences could be much larger.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This method can be adjusted also if you want to maximize power during the winter months, that are usually the most challenging ones for a solar power supply.&#xA;If you area have large temperature variations and want to get fancy, you can also incorporate the effect of temperature in solar panels' efficiency.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-03-25T04:08:19.940" LastActivityDate="2019-03-25T04:08:19.940" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16570" PostTypeId="1" AcceptedAnswerId="16575" CreationDate="2019-03-25T00:13:42.297" Score="9" ViewCount="18923" Body="&lt;p&gt;Is there a formula given the temperature, dew point, and pressure to find relative humidity?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have seen several calculators like &lt;a href=&quot;http://www.michell.com/us/calculator/&quot; rel=&quot;noreferrer&quot;&gt;this one&lt;/a&gt;, but I would like to know how to calculate this myself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am aware that there are several formulas that can calculate this with just the temperature and dew point, but since I'm writing a program, I would like to be able to use the pressure data that I have for greater accuracy.&lt;/p&gt;&#xA;" OwnerUserId="15513" LastEditorUserId="15513" LastEditDate="2019-03-25T13:34:15.207" LastActivityDate="2021-02-16T08:25:42.417" Title="How to calculate relative humidity from temperature, dew point, and pressure?" Tags="|meteorology|humidity|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16571" PostTypeId="5" CreationDate="2019-03-25T00:34:20.983" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2019-03-25T00:34:20.983" LastActivityDate="2019-03-25T00:34:20.983" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16572" PostTypeId="4" CreationDate="2019-03-25T00:34:20.983" Score="0" Body="The level of water vapor in the atmosphere. Use this tag for questions about either relative or specific humidity." OwnerUserId="15513" LastEditorUserId="15513" LastEditDate="2019-03-25T02:23:29.963" LastActivityDate="2019-03-25T02:23:29.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16575" PostTypeId="2" ParentId="16570" CreationDate="2019-03-25T02:31:34.010" Score="9" Body="&lt;p&gt;You can refer to &lt;a href=&quot;https://earthscience.stackexchange.com/q/14899/11908&quot;&gt;this question&lt;/a&gt; for more detail on the origin of this formula (based on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Dew_point&quot; rel=&quot;nofollow noreferrer&quot;&gt;Magnus approximation&lt;/a&gt;), but if you do some algebra to the expression there for dew point (&lt;span class=&quot;math-container&quot;&gt;$TD$&lt;/span&gt;) as function of temperature (&lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt;) and relative humidity (&lt;span class=&quot;math-container&quot;&gt;$RH$&lt;/span&gt;), you get&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$RH=100 \, e^{\Large \left(\frac{c\, b (TD-T)}{(c+T) (c+TD)}\right)}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;With &lt;span class=&quot;math-container&quot;&gt;$b=17.625$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$c=243.04$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;In this case, where &lt;span class=&quot;math-container&quot;&gt;$TD$&lt;/span&gt; is one of your input variables, there is no need to consider the pressure, pressure have no effect in &lt;span class=&quot;math-container&quot;&gt;$RH$&lt;/span&gt;, or more accurately, the pressure dependence is already considered through &lt;span class=&quot;math-container&quot;&gt;$TD$&lt;/span&gt;.&#xA;The pressure would come into play if you are computing &lt;span class=&quot;math-container&quot;&gt;$TD$&lt;/span&gt; from water vapour pressure, because water vapour pressure is what have a &lt;a href=&quot;https://en.wikipedia.org/wiki/Relative_humidity#Pressure_dependence&quot; rel=&quot;nofollow noreferrer&quot;&gt;small dependence&lt;/a&gt; in atmospheric pressure.&lt;/p&gt;&#xA;&lt;p&gt;The Magnus approximation above is considered valid for:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$0^oC &amp;lt; T &amp;lt; 60^oC$&lt;/span&gt;&lt;br&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$1\% &amp;lt; RH &amp;lt; 100\%$&lt;/span&gt;&lt;br&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$0^oC &amp;lt; TD &amp;lt; 50^oC$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;There are also other equivalent formulas that extends their validity range by changing the constants, like this one&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$RH=100\cdot10^{\Large m\left( \frac{TD}{TD+T_n}-\frac{T}{T+T_n}\right)}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where values for the constants &lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$T_n$&lt;/span&gt; depend on temperature and are tabulated:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/N6CnN.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/N6CnN.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;See &lt;a href=&quot;https://web.archive.org/web/20200212215746im_/https://www.vaisala.com/en/system/files?file=documents/Humidity_Conversion_Formulas_B210973EN.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this document&lt;/a&gt; for more details.&lt;/p&gt;&#xA;&lt;p&gt;There are also very simple approximations to these formulas, like&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$RH \approx 100 - 5 (T-TD)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;You can find a discussion on the accuracy of this approximation &lt;a href=&quot;https://en.wikipedia.org/wiki/Dew_point#Simple_approximation&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="15513" LastEditDate="2021-02-16T08:25:42.417" LastActivityDate="2021-02-16T08:25:42.417" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16576" PostTypeId="1" CreationDate="2019-03-25T03:05:47.697" Score="5" ViewCount="38" Body="&lt;p&gt;Assuming no change in sea level (for the sake of argument), is it possible to know the high and low tides a half century or more in the future?  Is information like this available to the general public? &lt;/p&gt;&#xA;" OwnerUserId="14986" LastActivityDate="2019-03-25T03:05:47.697" Title="Is it possible to know the tides of a particular location 50 years or 100 years from now?" Tags="|tides|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16577" PostTypeId="1" AcceptedAnswerId="20138" CreationDate="2019-03-25T05:01:05.553" Score="5" ViewCount="730" Body="&lt;p&gt;This figure from Wikipedia's &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Earth&quot; rel=&quot;noreferrer&quot;&gt;Atmosphere of Earth&lt;/a&gt; shows a hydrogen fraction of 0.000055 percent by volume.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Where does molecular hydrogen in the atmosphere come from?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does this come directly from biological production like much of the CO2 and CH4, or is this coming from geological sources or breakdown of methane by atmospheric chemistry for example, or someplace else?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Related: &lt;a href=&quot;https://biology.stackexchange.com/q/80302/27918&quot;&gt;What are the sources of molecular hydrogen in human breath?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Atmosphere_gas_proportions.svg&quot; rel=&quot;noreferrer&quot;&gt;Gas proportions in the Earth's lower atmosphere&lt;/a&gt;; &quot;The proportion of water vapor (H₂O) is variable so it is not represented in this chart, however it averages about 1% in the troposphere.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7DTAl.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7DTAl.png&quot; alt=&quot;Atmosphere gas proportions&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2019-03-25T11:29:09.887" LastActivityDate="2020-08-29T20:29:49.437" Title="Where does molecular hydrogen in the atmosphere come from?" Tags="|atmosphere|geochemistry|atmospheric-chemistry|biogeochemistry|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16578" PostTypeId="1" CreationDate="2019-03-25T06:16:03.110" Score="1" ViewCount="20" Body="&lt;p&gt;I'm looking to model the impact of broad scale atmospheric circulation changes on the hydrogen isotope ratio of precipitation for a given region. As an example, what impact does a high pressure system over China have on the hydrogen isotope composition of rainfall in northern Australia? I wondered if there are any open source coupled atmosphere/precipitation isotope models that have been developed for this type of work?&lt;/p&gt;&#xA;" OwnerUserId="15515" LastActivityDate="2019-03-25T06:16:03.110" Title="Model impact of atmopsheric circulation changes on precipitation dD of a region" Tags="|atmosphere|models|precipitation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16579" PostTypeId="1" CreationDate="2019-03-25T13:46:41.510" Score="4" ViewCount="79" Body="&lt;p&gt;In my research, finding and understanding info relating to the lower end of (conventional) surface seismic data acquisition (i.e. 15 - 1 Hz) is relatively simple. However, when I look at specs for a given type of common geophone, signal at and beyond 100 - 120 Hz is not really commented on or ignored altogether. Indeed, it seems that knowing what is &lt;em&gt;real&lt;/em&gt; or usable on the upper bandwidth limits of sensors is left alone for reasons I can't fathom.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In light of this, how can we reliably claim that data beyond the upper bandwidth limit of a sensor is usable? For example, I recently read a MASW-related paper (&quot;Enhancing the High-Frequency MASW Method&quot;) that used 40-Hz sensors for the study and - as part of the conclusions - declared that &quot;It is remarkable that all dispersion curves curves can be identified up to 1,600 Hz...&quot; Perhaps this is true but I want the proof to support it.&lt;/p&gt;&#xA;" OwnerUserId="8447" LastEditorUserId="28050" LastEditDate="2019-03-25T14:55:31.727" LastActivityDate="2019-03-25T14:55:31.727" Title="Seismic data acquisition: reliability of high-bandwidth data" Tags="|geophysics|seismic|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16580" PostTypeId="1" CreationDate="2019-03-25T23:16:47.450" Score="4" ViewCount="645" Body="&lt;p&gt;We know that presently Sun is 4.5 billion years into its main sequence. It has another 5 billion years before it enters the Red Giant phase. We also know that Sun's luminosity increases by 10% every billion years during the main sequence. I am interested in finding the temperature rise as we approach the end of main sequence. I got two different values for temperature on Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Future_of_Earth#Loss_of_oceans&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; entry says that temperature on Earth would be 422 k in 2.8 billion years. However, if we use the formula for effective temperature as discussed in this answer &#xA;&lt;a href=&quot;https://earthscience.stackexchange.com/a/4274/15299&quot;&gt;https://earthscience.stackexchange.com/a/4274/15299&lt;/a&gt; and L = 1.8 then, the temperature on Earth would be 330K. Also in &lt;a href=&quot;https://www.springer.com/us/book/9783319649603&quot; rel=&quot;nofollow noreferrer&quot;&gt;this book&lt;/a&gt;, the author does the same calculations on page 255. &lt;/p&gt;&#xA;" OwnerUserId="15299" LastEditorUserId="11908" LastEditDate="2019-03-26T04:50:26.197" LastActivityDate="2019-03-30T18:27:22.643" Title="What will be the temperature on Earth when Sun finishes its main sequence?" Tags="|geophysics|hypothetical|astronomy|energy-balance|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16581" PostTypeId="2" ParentId="16580" CreationDate="2019-03-26T01:44:35.283" Score="4" Body="&lt;p&gt;Answers will be different because they must be tied to a model of solar evolution, and all models are a bit different.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to answer your question we have to select a model. A pretty standard and trusted one, is the one used in the paper &lt;a href=&quot;https://academic.oup.com/mnras/article/298/2/525/1056616&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stellar evolution models for Z = 0.0001 to 0.03&lt;/a&gt;. Where Z stands for the &lt;a href=&quot;https://en.wikipedia.org/wiki/Metallicity&quot; rel=&quot;nofollow noreferrer&quot;&gt;metalicity&lt;/a&gt; of the star, that for the Sun they indicate would be 0.0188.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In figure 2, they show the trajectory of a star like the sun in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hertzsprung%E2%80%93Russell_diagram&quot; rel=&quot;nofollow noreferrer&quot;&gt;H-R diagram&lt;/a&gt; (look for the line labeled &quot;1.0&quot;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1i9Sk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1i9Sk.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data output of this model is available at the &lt;a href=&quot;http://vizier.u-strasbg.fr/viz-bin/VizieR-3?-source=J/MNRAS/298/525/summary&quot; rel=&quot;nofollow noreferrer&quot;&gt;VizieR catalog&lt;/a&gt;. I just downloaded the data for starts of one solar mass and Z=0.02 (like the Sun), and computed the &lt;a href=&quot;https://en.wikipedia.org/wiki/Effective_temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;effective temperature&lt;/a&gt; of Earth using the formula in the linked question&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\Large \frac{T}{T_0}=\left(\frac{L}{L_0}\right)^{\frac{1}{4}}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using a current effective temperature &lt;span class=&quot;math-container&quot;&gt;$T_0$&lt;/span&gt; of -19°C (you will find values between -18 and -21°C), we get that the plot of Luminosity and temperature versus time looks like this&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2pS6W.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2pS6W.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And given that you are interested in specific values here is some tabulated data including also the solar radius. Note that most of these points are linear interpolations of the original data, that had only six points in this age range.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Age         Radius      Lumin.  Temperature&#xA;[Billion    [solar      [Solar  [°C]&#xA; years]     radius]     Lumin.]&#xA;0.00        0.89        0.7     -41.4&#xA;0.25        0.90        0.7     -40.2&#xA;0.50        0.91        0.7     -39.0&#xA;0.75        0.91        0.7     -37.8&#xA;1.00        0.92        0.8     -36.6&#xA;1.25        0.93        0.8     -35.4&#xA;1.50        0.94        0.8     -34.2&#xA;1.75        0.95        0.8     -32.9&#xA;2.00        0.95        0.8     -31.7&#xA;2.25        0.96        0.8     -30.4&#xA;2.50        0.97        0.8     -29.2&#xA;2.75        0.98        0.9     -27.9&#xA;3.00        0.99        0.9     -26.7&#xA;3.25        1.00        0.9     -25.4&#xA;3.50        1.00        0.9     -24.1&#xA;3.75        1.01        0.9     -22.8&#xA;4.00        1.02        1.0     -21.5&#xA;4.25        1.03        1.0     -20.2&#xA;4.50        1.04        1.0     -18.9&#xA;4.75        1.05        1.0     -17.6&#xA;5.00        1.06        1.0     -16.3&#xA;5.25        1.07        1.1     -15.0&#xA;5.50        1.08        1.1     -13.7&#xA;5.75        1.08        1.1     -12.3&#xA;6.00        1.09        1.1     -11.0&#xA;6.25        1.10        1.2     -9.6&#xA;6.50        1.11        1.2     -8.3&#xA;6.75        1.12        1.2     -6.9&#xA;7.00        1.13        1.2     -5.5&#xA;7.25        1.14        1.3     -4.1&#xA;7.50        1.15        1.3     -2.8&#xA;7.75        1.16        1.3     -1.4&#xA;8.00        1.17        1.3     0.0&#xA;8.25        1.18        1.4     1.4&#xA;8.50        1.19        1.4     2.9&#xA;8.75        1.20        1.4     4.3&#xA;9.00        1.21        1.4     5.7&#xA;9.25        1.22        1.5     7.2&#xA;9.50        1.26        1.5     9.2&#xA;9.75        1.32        1.6     11.9&#xA;10.00       1.38        1.6     14.7&#xA;10.25       1.44        1.7     17.5&#xA;10.50       1.51        1.8     20.3&#xA;10.75       1.58        1.8     23.1&#xA;11.00       1.66        1.9     25.9&#xA;11.25       1.74        2.0     28.8&#xA;11.50       1.82        2.1     31.7&#xA;11.75       1.90        2.2     34.7&#xA;12.00       2.40        3.1     65.0&#xA;12.25       4.08        7.8     151.9&#xA;12.50       6.94        19.6    261.2&#xA;12.75       11.68       57.8    427.2&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Note that you can only know the &lt;a href=&quot;https://en.wikipedia.org/wiki/Effective_temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;effective temperature&lt;/a&gt;, the actual temperature will depend on the strength of the greenhouse effect, and modeling that is a whole new problem with huge uncertainties.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to this model, &lt;strong&gt;the terminal age main sequence of the Sun would be 9.38 Billion years, and according to the data above, the effective temperature then would be 8.2 °C (281 K), that's 27.2 °C hotter than today.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-03-30T18:27:22.643" LastActivityDate="2019-03-30T18:27:22.643" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="16586" PostTypeId="1" CreationDate="2019-03-26T11:55:54.880" Score="1" ViewCount="113" Body="&lt;p&gt;According to &lt;a href=&quot;https://agrf.org/africas-ministers-pledge-to-commercialise-regions-agricultural-sector/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Africas Ministers pledge to commercialise regions agricultural sector&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Speaking during a ministerial roundtable meeting at the AGRF in Kigali, Rwanda, the leaders noted that the economic health of the continent lies in the ability to earn from its biggest natural resource – land. Africa has 600 million hectares of uncultivated arable land, which is roughly 60 percent of the global total.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;How are this 600 million hectares land distributed among the countries? I'm specifically asking for how many hectares of arable land each of Africa's 54 country has. &lt;/p&gt;&#xA;" OwnerUserId="9635" LastEditorUserId="595" LastEditDate="2019-03-26T14:56:22.740" LastActivityDate="2019-03-26T14:56:22.740" Title="Where are Africa's 600 million hectares of arable land located?" Tags="|soil|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16587" PostTypeId="1" AcceptedAnswerId="16591" CreationDate="2019-03-26T16:07:06.653" Score="3" ViewCount="395" Body="&lt;p&gt;If we look at the &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;carbon cycle&lt;/a&gt;, we see that man-made carbon emission only account for a tiny fraction of all &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; emissions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, we see a steady rise in atmospheric &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt;-levels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wouldn't it be logical to assume that earth would somehow adapt to this increase, e.g. through increased plant growth and why isn't this happening?&lt;/p&gt;&#xA;" OwnerUserId="15523" LastEditorUserId="11908" LastEditDate="2019-04-06T20:06:51.383" LastActivityDate="2022-11-09T16:49:56.413" Title="Why doesn't Earth absorb our carbon emissions?" Tags="|geology|geophysics|climate-change|carbon-cycle|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16588" PostTypeId="1" AcceptedAnswerId="16621" CreationDate="2019-03-26T17:08:43.667" Score="7" ViewCount="4806" Body="&lt;p&gt;This is coming from a newcomer, so please be kind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I delve into the world of meteo data and reanalysis for the first time, I found that acquiring weather data is a lengthy process, so I'm shouting out for some help to get me started with it.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;What is the recommended workflow to acquire &lt;strong&gt;ERA5&lt;/strong&gt; data for a region of interest (ROI) for a few surface variables (precip, soilmoisutre, tempmin, solar rad)? &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Is there an API that connects me (R, Python, Curl) to the ERA5 database? &lt;/li&gt;&#xA;&lt;li&gt;Do I need to download whole (global) files even if my ROI is always within the same country? If so, are we talking about 100GB, 1,000GB or 10,000GB of data for 6 variables, whole historical?&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Seems like there are plenty of tools to extract ROI data from grib files. What is the recommended tool to learn in 2019? &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Is CDO the most appropriate tool for the job? &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Any Python/R packages that can extract and plot these data in an efficient way?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Thanks and let me know how to complement the info above&lt;/p&gt;&#xA;" OwnerUserId="7689" LastEditorUserId="7689" LastEditDate="2019-03-27T17:45:38.500" LastActivityDate="2019-09-10T08:41:47.307" Title="Extracting Regional Data from ERA5" Tags="|meteorology|reanalysis|era|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="16589" PostTypeId="1" CreationDate="2019-03-27T10:11:59.677" Score="2" ViewCount="91" Body="&lt;p&gt;Each hourly weather forecast has two columns with date and time. The first column: forecast creation date and time (the column (1) in a table below). The second column: forecast hour (the column (2) in the table below).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there an established term for the second column? Points? Slices?&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://weather.com/weather/hourbyhour/l/USNY0996:1:US&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Weather Company&lt;/a&gt; uses 'Time' name for this column.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/model-data/model-datasets/global-forcast-system-gfs&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA&lt;/a&gt; uses 'Output Timestep' name for this column in the GFS forecast model.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;And also, is there the right term for the first column?&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Table with example of hourly weather forecast&#xA;+--------------------+---------------+----------------+&#xA;| Forecast Creation  | Forecast Hour | Temperature, K |&#xA;| Date and Time (1)  |       (2)     |      (3)       |&#xA;+--------------------+---------------+----------------+&#xA;| 2019-03-28, 00-00  | +0            | 303            |&#xA;| 2019-03-28, 00-00  | +3            | 305            |&#xA;| 2019-03-28, 00-00  | +6            | 307            |&#xA;~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~&#xA;| 2019-03-28, 06-00  | +0            | 307            |&#xA;| 2019-03-28, 06-00  | +3            | 308            |&#xA;| 2019-03-28, 06-00  | +6            | 309            |&#xA;~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="15528" LastEditorUserId="15528" LastEditDate="2019-03-28T04:10:20.067" LastActivityDate="2020-02-13T12:51:20.057" Title="Is there the right term for time points in hourly weather forecast?" Tags="|terminology|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16591" PostTypeId="2" ParentId="16587" CreationDate="2019-03-27T17:11:12.390" Score="6" Body="&lt;p&gt;That assumption is indeed logical and correct, and increased plant growth is in fact happening (this effect is known as &lt;a href=&quot;https://en.wikipedia.org/wiki/CO2_fertilization_effect&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; fertilization&lt;/a&gt;). As you suggests, Earth will adapt to the increased inflow of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt;, and it will find equilibrium again. What might be missing in your reasoning, is the fact that the atmospheric &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; concentration in the new steady state would not be the same as the concentration in the pre-industrial steady state.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The atmosphere is a reservoir of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt;. Its has sources (volcanoes, plant respiration, decomposition, fossil fuels combustion, etc.) and sinks (photosintesys, ocean uptake, silicate weathering, etc.). To simplify the system let's do an analogy with a bath tub.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's imagine a bath tub with a very powerful faucet and a sink.&#xA;Now let's start opening the faucet until the sink becomes overwhelmed by the incoming water and the level in the bath tube starts to rise.&#xA;As the level rise, the water pressure at the bottom will rise too, therefore, more water will rush through the sink. Eventually the water going trough the sink will match the water coming in, and the water level will stabilize. At this point we have reached steady state.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we open the faucet a bit more, the water level will rise again, up to a point where the bottom pressure allows the sink to catch up and a new steady state is reached, but this time &lt;strong&gt;at a higher water level&lt;/strong&gt;. Also, note that after we increase the inflow of water, it takes some time to reach the new steady state, and that time depends on the sizes of sources and sinks relative to the reservoir. In our example, if the same faucet and sink were in an Olympic swimming pool instead of a bath tub, the time would have been much larger.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Going back to Earth, the atmospheric &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; concentration was pretty much as steady state before the industrial revolution (if we consider ~1000 years time scales). Then, with the industrial revolution we increased the inflow of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; into the atmospheric reservoir. As a consequence, the ocean and erosion increased their &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; intake, and plats increased their photosynthesis rate. In that way Earth, as you correctly assumed is working its way back to a new equilibrium. However, to reach that equilibrium takes time, and once we reach it, the atmospheric &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; will be higher than the pre-industrial levels, and that will in turn lead to a stronger greenhouse effect, higher temperatures, and climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is also important to note, that the extra inflow of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; didn't just increase at one point and stopped (like our faucet). It is constantly increasing to higher and higher levels of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; production, making even harder for natural systems to bring Earth to a new equilibrium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first figure in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia article you linked&lt;/a&gt; shows this neatly:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/R6lRW.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/R6lRW.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can see here in white numbers the most significant pre-industrial sources and sinks (at ~1000 years time scales). We can see that humans produce 9 Gigatons of carbon per year (GtC/yr), due to that extra inflow, photosynthesis is taking 3 GtC/yr more than before, and the ocean is taking an extra 2 GtC/yr as well. However, that is not enough to counteract the 9 GtC/yr we produce, and that is increasing the amount of carbon in the atmosphere at 4 GtC/yr. This means the level in the atmospheric &quot;bath tub&quot; is still rising.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we were to keep those 9 GtC/yr we produce stable (i.e. not increasing production in the future). The concentration of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; in the atmosphere will rise to a level high enough that the sinks will match the sources, for example with plants taking 5 GtC/yr and the ocean 4 GtC/yr, that would nicely balance the production. But that new equilibrium atmospheric &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; concentration would be high enough to rise Earth's temperature several degrees and force a whole reorganization of the Earth's climates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, we have to say that some of these &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; intakes, like the oceanic one, don't come for free, and have their own nasty consequences, like ocean acidification.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-03-27T21:07:47.857" LastActivityDate="2019-03-27T21:07:47.857" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16594" PostTypeId="1" CreationDate="2019-03-28T09:09:34.323" Score="6" ViewCount="413" Body="&lt;p&gt;At North Hemisphere, main superficial currents turn clock-wise, because of &lt;a href=&quot;https://scijinks.gov/coriolis/&quot; rel=&quot;noreferrer&quot;&gt;Coriolis Effect&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would expect on Mediterranean Sea to have currents turning in the same sense, but, surrounding landmasses, this picture shows a counter-clockwise sense of rotation.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TMrnH.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TMrnH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: &lt;a href=&quot;https://www.researchgate.net/figure/Map-of-the-Mediterranean-Sea-with-the-name-of-the-sub-basins-main-currents-white-lines_fig1_316850029&quot; rel=&quot;noreferrer&quot;&gt;researchgate.net&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Why so?&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-03-28T09:16:34.103" LastActivityDate="2019-03-28T09:16:34.103" Title="Why do Mediterranean main currents surrounding landmasses turn counter-clockwise?" Tags="|oceanography|ocean-currents|coriolis|" AnswerCount="0" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="16595" PostTypeId="1" CreationDate="2019-03-24T05:00:03.760" Score="5" ViewCount="183" Body="&lt;p&gt;I understand gravitational differentiation caused the layered structure of Earth when it is still molten. However, why are the heavier constituents in a reduced state, i.e. metal &lt;span class=&quot;math-container&quot;&gt;$\text{Fe}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\text{Ni}$&lt;/span&gt;, instead of an oxidized state? Is this because of the high temperature and pressure?&lt;/p&gt;&#xA;" OwnerUserId="15432" OwnerDisplayName="Meatball Princess" LastActivityDate="2019-04-01T12:37:49.343" Title="Why is the core of Earth in a reduced state? ($\text{Fe}$ and $\text{Ni}$)" Tags="|core|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16596" PostTypeId="1" CreationDate="2019-03-28T23:50:15.103" Score="5" ViewCount="390" Body="&lt;p&gt;Are there equations for the radiative forcings of the three Milankovitch factors at any given time? Or a database of values?&lt;/p&gt;&#xA;" OwnerUserId="15542" LastEditorUserId="11908" LastEditDate="2019-03-29T22:45:07.703" LastActivityDate="2021-07-05T13:54:14.663" Title="Equations for Milankovitch Factors?" Tags="|geophysics|climate-change|climate|climate-models|astronomy|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16597" PostTypeId="2" ParentId="16595" CreationDate="2019-03-29T08:09:42.637" Score="4" Body="&lt;p&gt;Because there wasn't enough oxygen to oxidise all of it. There is only so much oxygen on Earth. Most of it went to oxidise the elements that have higher affinities to oxygen: silicon, magnesium, calcium, aluminium, etc. Iron and nickel have lesser affinity to oxygen, so you start by oxidising some of it, until there is no oxygen left.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But there is still unoxidised iron and nickel left! So this just sinks to the core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/7076/725&quot;&gt;Further reading&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-03-29T08:09:42.637" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16598" PostTypeId="1" CreationDate="2019-03-29T22:11:12.937" Score="1" ViewCount="722" Body="&lt;p&gt;How much height of a mountain or any topographic high, decreases for a million year averagely? What is the range? (min / max) &lt;/p&gt;&#xA;" OwnerUserId="15195" LastActivityDate="2019-04-13T02:44:31.490" Title="What is the erosion rate of mountains?" Tags="|geomorphology|erosion|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16599" PostTypeId="2" ParentId="16596" CreationDate="2019-03-29T22:43:13.183" Score="5" Body="&lt;p&gt;There are many models that estimate orbital parameters at long timescales. All of them rely in rather complicated formulas that account for the perturbations generated by other planets, the Moon, and many other factors. Some of the models even consider relativistic effects as described in &lt;a href=&quot;https://earthscience.stackexchange.com/a/13663/11908&quot;&gt;this answer&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An orbital solution that I often see cited and used in papers dealing with climatic forcing is LA93, computed by Laskar et al. (1993) and described in the paper &lt;a href=&quot;http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?1993A%26A...270..522L&amp;amp;defaultprint=YES&amp;amp;filetype=.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Orbital, precessional, and insolation quantities for the Earth from -20 MYR to +10 MYR&lt;/a&gt;. However, more accurate solutions are available by now, like LA2004 and more notably LA2010. I'll describe below how to download output data and codes for each of these solutions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For LA93, the codes (in fortran) and outputs of that model are available at the &lt;a href=&quot;http://cdsarc.u-strasbg.fr/viz-bin/Cat?cat=VI%2F63&amp;amp;&quot; rel=&quot;nofollow noreferrer&quot;&gt;VizieR catalogue&lt;/a&gt;, where you can query the model output, or just go into &lt;a href=&quot;ftp://cdsarc.u-strasbg.fr/pub/cats/VI/63&quot; rel=&quot;nofollow noreferrer&quot;&gt;this FTP folder&lt;/a&gt; and download the files for the code and long tables with the model outputs every one thousand years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If by &quot;the three Milankovitch factors&quot; you mean Obliquity, Eccentricity, and   Precession index (Eccentricity &lt;span class=&quot;math-container&quot;&gt;$\times$&lt;/span&gt; sin(longitude of perihelion)). That data is ready to download and use in these two files:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;ftp://cdsarc.u-strasbg.fr/pub/cats/VI/63/CLIVAR0N.ASC&quot; rel=&quot;nofollow noreferrer&quot;&gt;CLIVAR0N.ASC (-20Myr to 0Myr)&lt;/a&gt;&lt;br&gt;&#xA;&lt;a href=&quot;ftp://cdsarc.u-strasbg.fr/pub/cats/VI/63/CLIVAR0P.ASC&quot; rel=&quot;nofollow noreferrer&quot;&gt;CLIVAR0P.ASC (0Myr to +10Myr)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The byte-per-byte description of these files as described in the &lt;a href=&quot;ftp://cdsarc.u-strasbg.fr/pub/cats/VI/63/ReadMe&quot; rel=&quot;nofollow noreferrer&quot;&gt;README&lt;/a&gt; is&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;--------------------------------------------------------------------------------&#xA;   Bytes Format  Units   Label     Explanations&#xA;--------------------------------------------------------------------------------&#xA;   4- 11  F8.0   1000yr  t         Time from J2000 in 1000 years&#xA;  13- 31  D19.12 ---     e         Eccentricity&#xA;  33- 51  D19.12 rad     eps       obliquity (radians)&#xA;  53- 71  D19.12 ---     CP        e * sin(longitude of perihelion&#xA;                                           from moving equinox)&#xA;--------------------------------------------------------------------------------&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;With the code you can also compute common climatic proxies such as isolation at 65°N or any other latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For LA2004 (-50 Myr to +20 Myr) the same research team implemented a very useful &lt;a href=&quot;http://vo.imcce.fr/insola/earth/online/earth/online/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;online calculator&lt;/a&gt; that allows to compute insolation quantities derived from the orbital and precessional quantities for any latitude of interest. It outputs the results in tabular form. The calculator interface looks like this so you get an idea of the available options.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qkuMl.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qkuMl.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The LA2010 solution is described in the paper &lt;a href=&quot;https://www.aanda.org/articles/aa/pdf/2011/08/aa16836-11.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;La2010: a new orbital solution for the long-term motion of the Earth&lt;/a&gt;, and goes 250 Myr back in time. You can find similar data files and codes for this solution at the &lt;a href=&quot;http://vo.imcce.fr/insola/earth/online/earth/earth.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Astronomical Solutions for Earth Paleoclimates page&lt;/a&gt;. To my understanding, LA2010 represent the state-of-the-art solution for orbital parameters and it does include relativistic corrections as well.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-03-31T01:11:40.737" LastActivityDate="2019-03-31T01:11:40.737" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16600" PostTypeId="1" CreationDate="2019-03-30T02:24:37.003" Score="4" ViewCount="56" Body="&lt;p&gt;&lt;a href=&quot;http://glossary.ametsoc.org/wiki/Inertial_flow&quot; rel=&quot;nofollow noreferrer&quot;&gt;Inertial flow&lt;/a&gt; is given by the balance between Coriolis and centrifugal forces. A &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Geostrophic_flow&quot; rel=&quot;nofollow noreferrer&quot;&gt;geostrophic flow&lt;/a&gt; is given by a balance between Coriolis and the gradients of pressure. The frequency of the inertial flow is the Coriolis frequency (at 43.5N, the Coriolis frequency is &lt;span class=&quot;math-container&quot;&gt;$10^{−4}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$s^{−1}$&lt;/span&gt;, which is equivalent to an inertial period of 17.4h). To me this is just the time that a particle takes to perform a full rotation around its center of rotation. Why does this peak shows up in plot like &lt;a href=&quot;https://earthscience.stackexchange.com/a/8074/15547&quot;&gt;this&lt;/a&gt;? Is it because is carrying around a flow field at a certain smaller scale? In a perfect Inertial gyro, since it is at steady state, if you sample in one point you get always the same velocity, right? A perfect geostrophic balance does not have rotation, and I understand that in that case we would have frequency=0. But a little departure from that could give rise to large scale geostrophic gyro (like low pressure systems in the athmosphere). Would not that gyro be associated with a frequency, in the same way the inertial gyro has a frequency?  Why it is common to say the geostrophic flows do not have a frequency? For a geostrophic gyro it still takes a certain time to rotate around a center of rotation.&lt;/p&gt;&#xA;" OwnerUserId="15547" LastEditorDisplayName="user1066" LastEditDate="2019-03-30T02:46:50.897" LastActivityDate="2019-03-30T02:46:50.897" Title="Why an inertial gyro has a frequency and a geostrophic gyro does not?" Tags="|geophysics|oceanography|ocean-currents|coriolis|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16601" PostTypeId="2" ParentId="16595" CreationDate="2019-03-30T04:25:04.900" Score="1" Body="&lt;p&gt;&lt;strong&gt;Because the early earth and the current surface of the earth are very different conditions.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any oxidized iron present on the forming earth would have quickly ceased to be oxidized as the planet became molten, Once heated the oxygen would have quickly been stripped away by elements with higher affinity. Silicon for instance has a much higher affinity for oxygen, hence why much of the planet is composed of silicates. During formation as the the earths material separated out by density. oxygen and oxides are just too light compared to heavier metals. Any oxides present at the very beginning would have quickly given up the oxygen to other materials with higher affinity once it was heated as the earth built up enough mass and energy to become molten.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Today it is hard to find unoxidized iron on the surface, but life had to lock up many of the other oxidizable materials before iron started to oxidize in large amounts.  Most of the oxidized iron on earth was only oxidized after photosynthesis evolved and flooded the atmosphere with oxygen (from splitting water), the core is incredibly well insulated from that oxygen,  free oxygen is too light to be transported down by mantle convection. Not that it would have made much difference even if you used all the oxygen in the atmosphere it would not oxidize even 1% of the core. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2019-04-01T12:37:49.343" LastActivityDate="2019-04-01T12:37:49.343" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="16602" PostTypeId="2" ParentId="16598" CreationDate="2019-03-30T05:05:02.713" Score="3" Body="&lt;p&gt;This may not answer your question, but it indicates that erosion is extreme at high altitudes.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;More than 60 percent of the sediment delivered to the world's oceans in the prehuman world originated from erosion in mountainous areas with elevations greater than 3 km above sea level.&lt;br&gt;&#xA;  &lt;a href=&quot;http://www.phschool.com/science/science_news/articles/muddy_waters.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Muddy Waters -&#xA;  More sediment is entering rivers, but less makes its way to the sea&#xA;  &lt;/a&gt;- Sid Perkins&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Only about 1% of Earth's area is above 3 km.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/I06TG.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;br&gt;&#xA;  (Fig. 2.4 of &lt;a href=&quot;https://books.google.com/books?id=vqgfH9DXXNAC&amp;amp;printsec=frontcover&amp;amp;dq=Deep-Sea%20Biology:%20A%20Natural%20History%20of%20Organisms%20at%20the%20Deep-Sea%20Floor&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwix-sPbjYDaAhWCZd8KHQ1xDsEQ6AEIJzAA#v=onepage&amp;amp;q=Deep-Sea%20Biology%3A%20A%20Natural%20History%20of%20Organisms%20at%20the%20Deep-Sea%20Floor&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;Deep-Sea Biology: A Natural History of Organisms at the Deep-Sea Floor&lt;/a&gt;) (&lt;a href=&quot;https://earthscience.stackexchange.com/a/2195/6535&quot;&gt;via DavePhD&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-03-30T05:05:02.713" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16603" PostTypeId="1" AcceptedAnswerId="16604" CreationDate="2019-03-30T08:36:00.790" Score="2" ViewCount="61" Body="&lt;p&gt;Wikipedia says for &lt;a href=&quot;https://en.wikipedia.org/wiki/QAPF_diagram&quot; rel=&quot;nofollow noreferrer&quot;&gt;QAPF diagrams&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;A QAPF diagram is a double ternary diagram which is used to classify&#xA;  igneous rocks based on mineralogic composition.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Why don't pyroxenites and peridotites appear on this diagram?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Aren't they igneous rocks? &lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastActivityDate="2019-03-30T08:58:51.487" Title="Why don't pyroxenites and peridotites appear in Streckeisen's QAPF diagram?" Tags="|rocks|petrology|igneous|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16604" PostTypeId="2" ParentId="16603" CreationDate="2019-03-30T08:58:51.487" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Why don't pyroxenites and peridotites appear on this diagram?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Because they do not have any quartz, feldspars, or felspathoids.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same Wikipedia page also says this:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;QAPF diagrams are also not used if mafic minerals make up more than 90% of the rock composition (for example: peridotites and pyroxenites).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Instead, we use a different diagram, that has olivine, orthopyroxene, and clinopyroxene at the vertices. &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Peridotite_Olivine-Orthopyroxene-Clinopyroxene_-_Common_Peridotites_highlighted.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Like this one right here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Aren't they igneous rocks? &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not necessarily, actually. But that's a completely different question.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-03-30T08:58:51.487" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16606" PostTypeId="1" CreationDate="2019-03-30T17:03:53.590" Score="4" ViewCount="301" Body="&lt;p&gt;One key target set out by the IPCC is to be carbon neutral by 2050. That is, the gross green house gas emissions of Humans is less than the carbon absorbed. I'm struggling to find a good source for the value of that second number. &lt;strong&gt;What is the volume of GHGs that are absorbed yearly, globally.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Eye-balling the &lt;a href=&quot;https://www.ipcc.ch/sr15/chapter/summary-for-policy-makers/c/spm3a/&quot; rel=&quot;nofollow noreferrer&quot;&gt;net emissions&lt;/a&gt; set out in the IPCC 1.5 special report, and the total gross emissions referenced in &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_countries_by_greenhouse_gas_emissions&quot; rel=&quot;nofollow noreferrer&quot;&gt;this Wikipedia page&lt;/a&gt;, puts the number at about of 5Gt CO₂e. Is this correct, and is there a more precise source for this? Or have I misunderstood something?&lt;/p&gt;&#xA;" OwnerUserId="15500" LastEditorUserId="6031" LastEditDate="2019-04-09T01:29:59.347" LastActivityDate="2019-04-09T01:29:59.347" Title="Is &quot;Carbon Neutral&quot; (roughly) 5 Gt CO₂ equivalent?" Tags="|climate-change|carbon-cycle|" AnswerCount="1" CommentCount="6" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16607" PostTypeId="1" CreationDate="2019-03-30T17:59:40.377" Score="5" ViewCount="60" Body="&lt;p&gt;It is common knowledge that age of the Earth is roughly 4.5 billion years. Radiometric dating of meteorites (which were formed during the formation of Earth) and earliest rocks on Earth have both arrived at the same values. I was wondering if there are any other scientific methods which also support or concur with the radiometric techniques.&lt;/p&gt;&#xA;" OwnerUserId="15299" LastActivityDate="2019-03-30T17:59:40.377" Title="Age of the Earth without radiometric dating?" Tags="|earth-history|dating|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16611" PostTypeId="1" CreationDate="2019-03-31T10:56:18.893" Score="3" ViewCount="21" Body="&lt;p&gt;Oceanic Crust is more dense than continental one. The margin between both types of materials can be passive or develop a subduction zone, where Oceanic Crust sinks under continental one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know there is geological evidence of cases where Oceanic Crust obduce upon the continent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can it happen if Oceanic Crust is more dense?&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastActivityDate="2019-03-31T10:56:18.893" Title="Why do ophiolites obduce upon Continental Crust?" Tags="|plate-tectonics|crust|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16613" PostTypeId="1" CreationDate="2019-03-31T12:40:51.560" Score="4" ViewCount="43" Body="&lt;p&gt;The condition for convection to cease is that the Rayleigh number &lt;span class=&quot;math-container&quot;&gt;$$\mathrm{Ra}=\frac{g\rho\alpha L^3\Delta T}{\kappa\nu}\lessapprox 10^3.$$&lt;/span&gt; For the Earth's mantle I have seen estimates of &lt;span class=&quot;math-container&quot;&gt;$\mathrm{Ra}\approx 10^6$&lt;/span&gt; to &lt;span class=&quot;math-container&quot;&gt;$10^8$&lt;/span&gt;, which naively would mean we need to reduce &lt;span class=&quot;math-container&quot;&gt;$\Delta T$&lt;/span&gt; by a factor of &lt;span class=&quot;math-container&quot;&gt;$10^3$&lt;/span&gt; to &lt;span class=&quot;math-container&quot;&gt;$10^5$&lt;/span&gt; for convection to cease. In reality this is an overestimate since the thermal expansion &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt;, the thermal diffusivity &lt;span class=&quot;math-container&quot;&gt;$\kappa$&lt;/span&gt; and especially the viscosity &lt;span class=&quot;math-container&quot;&gt;$\nu$&lt;/span&gt; are temperature dependent. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, being a non-geologist I find it hard to find easy functional forms of these parameters in the literature since they also depend on a number of other things like pressure and are subject to big empirical uncertainties. Are there any canonical estimates for the necessary temperature difference, or qualitative models?&lt;/p&gt;&#xA;" OwnerUserId="12421" LastEditorUserId="725" LastEditDate="2019-04-01T01:05:10.620" LastActivityDate="2019-04-01T01:05:10.620" Title="What is the minimum temperature difference to drive mantle convection?" Tags="|geophysics|mantle|convection|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16617" PostTypeId="2" ParentId="16309" CreationDate="2019-03-31T21:14:30.503" Score="1" Body="&lt;p&gt;The name of the cavities are lithophysae. They show that the current has high volatile content. Vapor phase devitrification is the origin of litophysae. Pyroclasts in the curremt maintain their volatile content till compaction. volatiles escapes from the clasts during deposition to the weakness zones of the flowage. After exsolution, the laminae (source of the volatile) will be compacted and vapor phase minerals tridymite, crystobalite and feldpspar crystallized. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cavities don't have to be on the top of the pyroclastic density current. They may occur on the flowage shearing surfaces and a syn-depositional incident. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer is not complete but it may give some idea.&lt;/p&gt;&#xA;" OwnerUserId="15195" LastActivityDate="2019-03-31T21:14:30.503" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16621" PostTypeId="2" ParentId="16588" CreationDate="2019-04-01T16:40:27.340" Score="5" Body="&lt;p&gt;To me I am not sure why the subset option should not work with a python script. According to me it &lt;em&gt;does&lt;/em&gt; work. Here is a sample script.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;import cdsapi&#xA;&#xA;c = cdsapi.Client()&#xA;&#xA;c.retrieve(&#xA;'reanalysis-era5-single-levels',&#xA;{&#xA;    'variable':'total_precipitation',&#xA;    'product_type':'reanalysis',&#xA;    'year':'2010',&#xA;    'month':'04',&#xA;    'day':'07',&#xA;    'area':'60/0/0/100',&#xA;    'time':[&#xA;        '00:00','01:00','02:00',&#xA;        '03:00','04:00','05:00',&#xA;        '06:00','07:00','08:00',&#xA;        '09:00','10:00','11:00',&#xA;        '12:00','13:00','14:00',&#xA;        '15:00','16:00','17:00',&#xA;        '18:00','19:00','20:00',&#xA;        '21:00','22:00','23:00'&#xA;    ],&#xA;    'format':'netcdf'&#xA;},&#xA;'precip.nc')&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE&lt;/strong&gt;&#xA;In response to some of the comments raised by @Nemesi - with this CDS Python API &#xA;&lt;strong&gt;&lt;a href=&quot;https://stackoverflow.com/questions/25731393/is-there-a-way-to-crop-a-netcdf-file&quot;&gt;There is no need to use CDO or NCO to subset the data&lt;/a&gt;&lt;/strong&gt;. The API itself takes care of it for you using the keyword &lt;strong&gt;area&lt;/strong&gt;. Once you specify the bounding box the data that goes get downloaded is the bounding box boundaries you specify. There is also NO programmatic subsetting of global data. Right now the CDS web interface does not allow you to do subsetting(the problem is being fixed as I write according to Copernicus support). But that is not really a problem. Since OP's requirement is one of automating the process the CDS Python Web API fills the purpose. In this context subset is the same as ROI or region of interest. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is what I had to do get this to work. I had to install the &lt;a href=&quot;https://pypi.org/project/cdsapi/&quot; rel=&quot;nofollow noreferrer&quot;&gt;cdsapi for python&lt;/a&gt;. One can do this using pip (I usually do it - python3.6 setup.py install since I do not have conda). Then create a .cdsapirc(on Linux and other UNIX flavors it should be under the main home directory. Create this file wherever you have the $HOME variable defined) which should be like this - &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;url: https://cds.climate.copernicus.eu/api/v2&#xA;key: {UID}:{API key}&#xA;verify:0&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The values of UID and API key you should get when you register at the new CDS web interface site. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;And then just run it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here the key parameter is the  &lt;strong&gt;&lt;em&gt;area&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and the first two values are starting latitude and longitude followed by the ending latitude and  longitude. When I viewed the downloaded netCDF file using ncdump it did have the right bounding box values. Now you could change it to GRIB format if you so wish but I think the basic format of the script does not change. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a plot of the subset of the precipitation for a specific instant in a 24 hour period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is the code that plots it (I use &lt;a href=&quot;https://matplotlib.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;matplotlib&lt;/a&gt; and &lt;a href=&quot;https://scitools.org.uk/cartopy/docs/latest/&quot; rel=&quot;nofollow noreferrer&quot;&gt;cartopy&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;from netCDF4 import Dataset,num2date&#xA;import cartopy.crs as ccrs&#xA;from cartopy.mpl.ticker import LongitudeFormatter, LatitudeFormatter&#xA;from cartopy.util import add_cyclic_point&#xA;import matplotlib as mpl&#xA;mpl.rcParams['mathtext.default'] = 'regular'&#xA;import matplotlib.pyplot as plt&#xA;import numpy as np&#xA;&#xA;&#xA;file = &quot;precip.nc&quot;&#xA;nc_pvFile = Dataset(file,'r')&#xA;lats = nc_pvFile.variables['latitude'][:]  # extract/copy the data&#xA;lons = nc_pvFile.variables['longitude'][:]&#xA;lats = lats[:].squeeze()&#xA;lons = lons[:].squeeze()&#xA;&#xA;preciPlot = nc_pvFile.variables['tp'][:]&#xA;&#xA;pp = preciPlot[0,:,:]&#xA;&#xA;&#xA;ax1 = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))&#xA;clevs = np.arange(min(pp.flatten()),max(pp.flatten())*1000,1)&#xA;&#xA;&#xA;shear_fill = ax1.contourf(lons,lats,pp*1000,clevs,&#xA;                      transform=ccrs.PlateCarree(),cmap=plt.get_cmap('hsv'),&#xA;                                                                      linewidth=(10,),levels=100,extend='both')&#xA;&#xA;ax1.coastlines()&#xA;ax1.gridlines()&#xA;ax1.set_xticks([0, 10,20,30,40,50,60,70,80,90,100], crs=ccrs.PlateCarree())&#xA;ax1.set_yticks([0, 10,20,30,40,50,60], crs=ccrs.PlateCarree())&#xA;lon_formatter = LongitudeFormatter(zero_direction_label=True,&#xA;                               number_format='.0f')&#xA;lat_formatter = LatitudeFormatter()&#xA;ax1.xaxis.set_major_formatter(lon_formatter)&#xA;ax1.yaxis.set_major_formatter(lat_formatter)&#xA;cbar = plt.colorbar(shear_fill, orientation='horizontal')&#xA;plt.title('Total precipitation', fontsize=16)&#xA;plt.savefig('precip_era.png')&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/v4UWg.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/v4UWg.png&quot; alt=&quot;precip&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-04-03T03:21:37.187" LastActivityDate="2019-04-03T03:21:37.187" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="16622" PostTypeId="2" ParentId="15697" CreationDate="2019-04-01T16:48:56.390" Score="2" Body="&lt;p&gt;It is related with the large-scale geology of the USA and Europe. The USA is rather normal in this regard, but the particular geological history of Europe allowed the formation of exceptionally deep caves there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During &lt;a href=&quot;https://en.wikipedia.org/wiki/Mesozoic&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mesozoic&lt;/a&gt;, Europe was a closed ocean: the &lt;a href=&quot;https://en.wikipedia.org/wiki/Tethys_Ocean&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tethys Ocean&lt;/a&gt;, with shallow carbonated platforms. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Alpine_orogeny&quot; rel=&quot;nofollow noreferrer&quot;&gt;Alpine Orogeny&lt;/a&gt; formed the continent and the carbonaceous materials emerged creating mountains with large carbonaceous units. The meteorization and erosion of these carbonates created big &lt;a href=&quot;https://en.wikipedia.org/wiki/Karst&quot; rel=&quot;nofollow noreferrer&quot;&gt;karstic systems&lt;/a&gt; with deep caves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Conversely, the USA has a lot of &lt;a href=&quot;https://en.wikipedia.org/wiki/Paleozoic&quot; rel=&quot;nofollow noreferrer&quot;&gt;Paleozoic&lt;/a&gt; units where the carbonaceous materials are too compact to form deep caves. You may have shallow Mesozoic caves near the surface but Mesozoic units are thinner than some folded zones of Europe.&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-04-01T17:59:26.483" LastActivityDate="2019-04-01T17:59:26.483" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16626" PostTypeId="2" ParentId="15697" CreationDate="2019-04-02T00:17:11.467" Score="1" Body="&lt;p&gt;Deep caves primarily need two things: 1) Very thick or extensive tilted limestone beds so that there is enough bedrock to form a deep cave, and 2) A deep water table so that caves can form by dissolution of the limestone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although phreatic caves form beneath the water table, they seldom form to great depth because the water becomes saturated with calcium carbonate early in the groundwater flow system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A deep water table is promoted by uplift or by incising of rivers into plateaus. There are few areas in the US with these conditions as noted in the other answer.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2019-04-02T00:17:11.467" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16627" PostTypeId="1" AcceptedAnswerId="16629" CreationDate="2019-04-02T10:24:06.463" Score="4" ViewCount="353" Body="&lt;p&gt;The NPR News article &lt;a href=&quot;https://www.npr.org/sections/thesalt/2019/04/01/708818581/growing-corn-is-a-major-contributor-to-air-pollution-study-finds&quot; rel=&quot;nofollow noreferrer&quot;&gt;Growing Corn Is A Major Contributor To Air Pollution, Study Finds&lt;/a&gt; talks about all sources of pollution associated with growing corn, and it singles out the application of ammonia to the soil as a surprisingly polluting aspect.&lt;/p&gt;&#xA;&lt;p&gt;The article says that the ammonia which escapes the soil and is released into the atmosphere ultimately leads to the production of PM2.5 and is a major source of pollution harmful to people. It links to the new paywalled paper in Nature &lt;a href=&quot;https://www.nature.com/articles/s41893-019-0261-y&quot; rel=&quot;nofollow noreferrer&quot;&gt;Air-quality-related health damages of maize&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What would be the chemical and/or physical processes by which traces of ammonia in the air would lead to PM2.5 production?&lt;/p&gt;&#xA;&lt;p&gt;From the article:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The study estimates that &amp;quot;4,300 premature deaths can be attributed to corn production,&amp;quot; says Hill. &amp;quot;That's about a quarter of all [air pollution-related] agricultural deaths. That's significant.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;The vast majority, 86 percent, of PM2.5 emissions happen on farms, with the rest occurring elsewhere in the supply chain, according to the study. The main culprit?&lt;/p&gt;&#xA;&lt;p&gt;Fertilizer application.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Ammonia from fertilizer application accounted for about 70 percent of attributable deaths,&amp;quot; says Hill. The nitrogen in fertilizers helps fuel plant growth, but not all of it can be used by the plant. &amp;quot;Some of that nitrogen washes into waterways, and some of it gets released into the atmosphere as ammonia,&amp;quot; says Hill.&lt;/p&gt;&#xA;&lt;p&gt;Once ammonia hits the atmosphere, it reacts with other particles, mostly nitrogen and sulfur oxides, to form PM2.5, according to Hill.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;From the question in Biology SE &lt;a href=&quot;https://biology.stackexchange.com/q/65163/27918&quot;&gt;Why do soil bacteria produce nitrous oxide as a result of anhydrous ammonia fertilizer application?&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; &lt;em&gt;Anhydrous ammonia tanks in a newly planted wheat field. Walmart has promised big cuts in emissions of greenhouse gases. To meet that goal, though, the giant retailer may have to persuade farmers to use less fertilizer. It won't be easy.&lt;/em&gt; TheBusman/Getty Images. From &lt;a href=&quot;http://www.npr.org/sections/thetwo-way/2017/08/21/545083434/photos-the-day-the-eclipse-came-to-america&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/uI5gd.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uI5gd.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-04-09T03:42:42.627" Title="How can agricultural ammonia lead to PM2.5 production in the atmosphere?" Tags="|air-pollution|agriculture|particulates|pm2.5|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16628" PostTypeId="1" CreationDate="2019-04-02T10:57:00.770" Score="1" ViewCount="273" Body="&lt;p&gt;I am a newbie for hydrology. If the question seems to have &quot;well known answer&quot;, I appreciate if you point me to the resources. I will add details to the question based on comments.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider a town of 30km x 30km, nearby a hill, in a place where rain averages 40cm per year. The town is at an average elevation of 30m compared to the surroundings. It gets water mainly from rain. The water table seems to drop off as we walk away from the hill (30m near the hill, 90m once we walk 30km away from the hill).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we concertize the town (fill every road, every open place with concrete 1m thick), what effect would that have on water table (water availability in earth)? Would the water flow away and sink into outer places (away from the town)?&lt;/p&gt;&#xA;" OwnerUserId="15571" LastActivityDate="2019-04-04T03:13:29.923" Title="What effect does concretization (paving/flooring with concrete) has on ground water table" Tags="|hydrology|groundwater|water-table|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16629" PostTypeId="2" ParentId="16627" CreationDate="2019-04-02T13:01:54.607" Score="7" Body="&lt;h1&gt;Acid/Base Chemistry&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Gaseous ammonia (NH&lt;span class=&quot;math-container&quot;&gt;$_3$&lt;/span&gt;) acts as a base when it dissolves in water. The reactions are below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NH&lt;span class=&quot;math-container&quot;&gt;$_3$&lt;/span&gt;(g) + H&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;O(l) &lt;span class=&quot;math-container&quot;&gt;$\rightleftharpoons$&lt;/span&gt; NH&lt;span class=&quot;math-container&quot;&gt;$_3$&lt;/span&gt;(aq)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;NH&lt;span class=&quot;math-container&quot;&gt;$_3$&lt;/span&gt;(aq) + H&lt;span class=&quot;math-container&quot;&gt;$_3$&lt;/span&gt;O&lt;span class=&quot;math-container&quot;&gt;$^+$&lt;/span&gt;(aq) &lt;span class=&quot;math-container&quot;&gt;$\rightleftharpoons$&lt;/span&gt; NH&lt;span class=&quot;math-container&quot;&gt;$_4^+$&lt;/span&gt;(aq) + H&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;O(l)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The end product is an ammonium ion. We also have gas phase species SO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; and NO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; in air. They dissolve in water to form the conjugates of the acids H&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;SO&lt;span class=&quot;math-container&quot;&gt;$_4$&lt;/span&gt; and HNO&lt;span class=&quot;math-container&quot;&gt;$_3$&lt;/span&gt; (e.g. SO&lt;span class=&quot;math-container&quot;&gt;$_4^{2-}$&lt;/span&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The protonized ammonium and the deprotonized acids (e.g. NO&lt;span class=&quot;math-container&quot;&gt;$_3^-$&lt;/span&gt;) are not gaseous anymore. They are also NOT solids. They are dissolved ions.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Precipitation and Nucleation&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Ammonium cations react with the acid anions in an acid/base reaction to form a salt complex. An example is ammonium sulfate (NH&lt;span class=&quot;math-container&quot;&gt;$_4$&lt;/span&gt;)&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;SO&lt;span class=&quot;math-container&quot;&gt;$_4$&lt;/span&gt;. When the concentration is low, salts remain as dissolved species in water. As the salt concentration increases, at some point, the salt condenses to a solid (it precipitates out of solution). Salt concentrations increase as the water droplets in the air take on more acid and base species. Salt concentrations also increase as the water droplets evaporate. This causes the water droplets to act as sites for the formation of solid salt particles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Air also contains other solids as ultra-fine particles. Think ... dust.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;All solid surfaces in water act as sites to catalyze the further capture of dissolved salts. They act as proton exchange mediators, better than the liquid phase itself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The process of formation of a solid particle or capture of a dissolved species onto a solid surface is called nucleation. Nucleation is followed by growth. Some of the solid salts can alternatively redissolve when the conditions are reversed ... e.g. the concentration of the salt in solution surrounding it decreases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The figure below illustrates the entire process using ammonia and nitric acids (formed from nitrogen dioxide).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2ebkv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2ebkv.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Image caption: The compounds in green colored font are located at (mostly wet) particle surfaces or are dissolved in droplet water. Compounds written in black colored font are gaseous. A second arrow head is missing at the arrow connecting gaseous &lt;span class=&quot;math-container&quot;&gt;$HNO_3$&lt;/span&gt; and particle-bounds &lt;span class=&quot;math-container&quot;&gt;$HNO_3$&lt;/span&gt;. Gaseous &lt;span class=&quot;math-container&quot;&gt;$NH_3$&lt;/span&gt; is missing in this figure.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because proton-exchange favorably takes place at surfaces or in droplets, the particles grow favorably rather than redissolve (see below).&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;References&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;An exemplary particle size distribution is shown below (&lt;em&gt;own work (&lt;a href=&quot;http://nbn-resolving.de/urn:nbn:de:gbv:18-81508&quot; rel=&quot;nofollow noreferrer&quot;&gt;Neumann, 2016, Fig. 2.1&lt;/a&gt;) but content based on Seinfeld and Pandis (2006a, Fig. 2.7,p.59) which is based on Whitby and Cantrell (1976)&lt;/em&gt;). The Y-axis shows particle abundance (roughly; please see Fig 2.2 in the linked document above for details).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/U037z.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/U037z.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The major source of the coarse particles on the right are primary emissions of particles (dust, sea salt, ...). The accumulation mode particles in the center are partly caused by primary emissions (fine sea salt, combustion processes, ...) and partly grown from smaller particles (Aitken mode or ultra-fine particles). Actually, the ultra-fine particles are grown from so called nucleation mode particles by the condensation of further atmospheric gaseous compounds. The nucleation mode is missing here (and merged with the Aitken mode). Nucleation mode particles are those particles, which are formed by ammonia and atmospheric acids.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other sources for these nucleation mode particles are gaseous organic compounds, which lump together to form particles. The latter particles are also called SOA (secondary organic aerosol). Isoprene is one of the compounds that forms SOA.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Health Impacts&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;When we combine air polluted by combustion emissions (&lt;span class=&quot;math-container&quot;&gt;$NO_X$&lt;/span&gt;) with air affected by agricultural emissions, we can expect the formation of ammonium nitrate particles (&lt;span class=&quot;math-container&quot;&gt;$NH_4^+$&lt;/span&gt; + &lt;span class=&quot;math-container&quot;&gt;$NO_3^-$&lt;/span&gt;). Ammonium nitrate can irritate the eyes, nose and lungs. As stated in a comment and to the best of my knowledge, ammonium nitrate particles are not as harmful as e.g. fine soot particles. But I am not a expert on this field.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ammonium sulfate (from &lt;span class=&quot;math-container&quot;&gt;$SO_2$&lt;/span&gt; from combustion emissions) have been shown to have negative health impacts on the respiratory system but also on the cardiovascular system (heart etc.; if the particles are sufficiently small to pierce the lung-blood barrier).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ultra fine ammonium nitrate particles can be nuclei for condensation of further gaseous compounds -- e.g. VOC (volatile organic compounds) --, which might have harmful impacts on our respiratory system.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;notes&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Commonly, atmospheric particles are not dry spheres/lumps of matter but somehow associated with water: water droplets with dissolved compounds or a solid core with water &lt;em&gt;attached&lt;/em&gt; to the surface; whereas dissolved compounds might be dissolved in the water of the latter type.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The atmospheric life time of gaseous acids is very short because they tend to get attached to water (and deprotonize -- reducing the pH value of the water). Partly, the reaction from precursors to acids takes place in the wet particle/droplet phase. E.g. most of produced sulfuric acid (&lt;span class=&quot;math-container&quot;&gt;$H_2SO_4$&lt;/span&gt;) takes place in the wet phase.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;tl;dr&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Thus, we foster the growth of ultra-fine nuclei by the condensation of ammonia (as base) and condensation/formation of acids. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Seinfeld and Pandis, 2006: &lt;em&gt;Atmospheric Chemistry and Physics: From Air Pollution to Climate Change&lt;/em&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Whitby and Cantrell, 1976: &lt;em&gt;Fine particles&lt;/em&gt; in &lt;em&gt;Proc. Int. Conf. Environ. Sens. and Asses&lt;/em&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="5594" LastEditorUserId="5594" LastEditDate="2019-04-03T19:48:42.317" LastActivityDate="2019-04-03T19:48:42.317" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="16631" PostTypeId="1" CreationDate="2019-04-03T14:06:45.570" Score="3" ViewCount="71" Body="&lt;p&gt;I am looking for a dataset of ensemble forecasts and the associated true observed values. For example, a dataset containing &lt;span class=&quot;math-container&quot;&gt;$n$&lt;/span&gt; ensemble forecasts of the temperature in 24 hours and the observed temperature 24 hours later. The &lt;a href=&quot;https://www.ecmwf.int/en/forecasts/datasets/browse-reanalysis-datasets&quot; rel=&quot;nofollow noreferrer&quot;&gt;ECMWF datasets&lt;/a&gt; look promising, but as a mathematician, I am not familiar with the terminology. Clicking on a dataset, &lt;a href=&quot;https://apps.ecmwf.int/datasets/data/cera-sat-enda/levtype=sfc/type=an/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this page&lt;/a&gt; for example, shows that &quot;Analysis&quot; and &quot;Forecast&quot; data is available. Are either of these the ensemble members or the observations? Downloading the data hasn't helped either.&lt;/p&gt;&#xA;" OwnerUserId="15582" LastEditorUserId="15582" LastEditDate="2019-04-03T16:27:16.873" LastActivityDate="2019-04-03T16:27:16.873" Title="Do any of the ECMWF ensemble forecasts have the associated true values?" Tags="|models|open-data|data-analysis|" AnswerCount="0" CommentCount="6" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16632" PostTypeId="1" AcceptedAnswerId="16633" CreationDate="2019-04-03T14:11:15.043" Score="7" ViewCount="1227" Body="&lt;p&gt;How the Madden-Julian Oscillation (MJO) index can be interpret?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's suppose I have got an MJO index value of 0.6 in a given day, what this does mean?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does 0.6 represents a weak MJO?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Data from &lt;a href=&quot;https://www.esrl.noaa.gov/psd/mjo/mjoindex/&quot; rel=&quot;noreferrer&quot;&gt;https://www.esrl.noaa.gov/psd/mjo/mjoindex/&lt;/a&gt;&#xA;Thanks&lt;/p&gt;&#xA;" OwnerUserId="11493" LastEditorDisplayName="user1066" LastEditDate="2019-04-03T14:25:50.177" LastActivityDate="2020-10-08T11:57:01.070" Title="Madden-Julian Oscillation (MJO) - How to interpret the index?" Tags="|meteorology|climate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16633" PostTypeId="2" ParentId="16632" CreationDate="2019-04-03T14:33:21.600" Score="8" Body="&lt;p&gt;I prefer to use the &lt;a href=&quot;http://www.bom.gov.au/climate/mjo/&quot; rel=&quot;noreferrer&quot;&gt;BOM MJO index&lt;/a&gt; and the explanation provided over there -&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;When the index is within the centre circle the MJO is considered weak, meaning it is difficult to discern using the RMM methods. Outside of this circle the index is stronger and will usually move in an anti-clockwise direction as the MJO moves from west to east. For convenience, we define 8 different MJO phases in this diagram. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So in your case your signal value is 0.6 and that means it is fairly weak in amplitude as it is inside the circle. You also need to mention the phase of the MJO phase diagram. There are eight phases&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Phase 1 &amp;amp; 8 - Western Hemisphere And Africa&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Phase 2 &amp;amp; 3 - Indian Ocean&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Phase 4 &amp;amp; 5 - Maritime Continent&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Phase 6 &amp;amp; 7 - Western Pacific.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Currently the signal is a weak one as seen in this phase diagram &lt;a href=&quot;http://www.bom.gov.au/climate/mjo/graphics/rmm.phase.Last40days.gif.small.gif&quot; rel=&quot;noreferrer&quot;&gt;MJO Phase diagram &lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the MJO signal is strong it's amplitude will be greater than 1 and the contour line will be outside the circle. It should be noted that the MJO is an empircal index consisting of the 850 hPa winds, OLR and 200 hPa winds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;MJO passage through phase 6 and 7 is always of global interest as the impact can be of planetary scale. Usually El Ninos are preceded by &lt;a href=&quot;https://en.wikipedia.org/wiki/Westerly_wind_burst&quot; rel=&quot;noreferrer&quot;&gt;Westerly Wind Bursts&lt;/a&gt; and the forcing factor can be a MJO passage through phase 6 and 7. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One can look at the raw data of the signal here - &lt;a href=&quot;http://www.bom.gov.au/climate/mjo/graphics/rmm.74toRealtime.txt&quot; rel=&quot;noreferrer&quot;&gt;RMM Index text&lt;/a&gt;. This provides the amplitude of the signal as well as the phase of the MJO. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another version of the same can be seen here - &lt;a href=&quot;http://iprc.soest.hawaii.edu/users/kazuyosh/ISO_index/data/MJO_25-90bpfil.rt_pc.txt&quot; rel=&quot;noreferrer&quot;&gt;MJO RMM index&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-04-03T15:52:21.630" LastActivityDate="2019-04-03T15:52:21.630" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16634" PostTypeId="1" CreationDate="2019-04-03T16:14:54.637" Score="1" ViewCount="49" Body="&lt;p&gt;I am new to time series data analysis. I wonder how would one test the difference between integrated quantities (area under curve) from different time-series curves? (the time series are plotted with biweekly GHG flux data, the flux data has standard error associated with it). Like comparing cumulative/annual total greenhouse gas emission in different geographical regions. Thank you very much.&lt;/p&gt;&#xA;" OwnerUserId="3241" LastEditorUserId="3241" LastEditDate="2019-04-03T17:46:13.270" LastActivityDate="2019-04-03T17:46:13.270" Title="Testing the statistical significance of the difference between cumulative/integrated emission quantities calculated from time series?" Tags="|greenhouse-gases|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="16636" PostTypeId="1" CreationDate="2019-04-03T22:05:21.297" Score="2" ViewCount="438" Body="&lt;p&gt;I have this project at university where I have to make an atmospheric visibility measuring device using Arduino. I talked with my teacher and he said that I should do something like &lt;a href=&quot;https://aviation.stackexchange.com/questions/16034/how-is-the-visibility-at-airports-measured&quot;&gt;this&lt;/a&gt;, using an emitter to transmit a laser beam and a receptor. This is all the information he gave me. I have never used Arduino before and I found almost nothing on the internet to help me. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can someone provide me with a starting point and explain what kind of components I should use (I have to buy everything myself) and how to build this device?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;" OwnerUserId="15585" LastEditorUserId="11908" LastEditDate="2019-04-04T01:29:44.170" LastActivityDate="2019-04-04T18:49:16.770" Title="Atmospheric visibility measuring device" Tags="|measurements|instrumentation|diy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16640" PostTypeId="1" AcceptedAnswerId="16649" CreationDate="2019-04-04T01:07:45.077" Score="1" ViewCount="265" Body="&lt;p&gt;I don't have a background in Geology but this question popped in my head the other day and can't find an answer anywhere else.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I remember science class correctly, Earth's layers have different element compositions. Would it be correct to assume that they have different densities and different frictions as a result? And if they do, does it follow from it that they rotate at different speeds?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks.&lt;/p&gt;&#xA;" OwnerUserId="15586" LastActivityDate="2019-04-04T20:57:59.413" Title="Do Earth's layers move at different speeds?" Tags="|earth-rotation|geologic-layers|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16641" PostTypeId="2" ParentId="16636" CreationDate="2019-04-04T02:00:29.453" Score="3" Body="&lt;p&gt;The transmissometer setup should be quite easy to build in principle, but it could be hard to get accurate values. I did a very similar instrument but to measure water transsmisivity (a.k.a. turbidity).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are new to Arduino you can start with the &lt;a href=&quot;https://store.arduino.cc/usa/arduino-uno-rev3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Arduino UNO&lt;/a&gt; board, and this is &lt;a href=&quot;https://www.arduino.cc/en/Guide/ArduinoUno&quot; rel=&quot;nofollow noreferrer&quot;&gt;a good guide on how to get started&lt;/a&gt;. I got started myself with the video tutorial &lt;a href=&quot;https://www.youtube.com/watch?v=09zfRaLEasY&quot; rel=&quot;nofollow noreferrer&quot;&gt;Arduino Course for Absolute Beginners&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Practice with a couple simple programs. In particular &quot;&lt;a href=&quot;https://www.arduino.cc/en/Tutorial/Blink&quot; rel=&quot;nofollow noreferrer&quot;&gt;Blink&lt;/a&gt;&quot; to get used to switch pins on and off and &quot;&lt;a href=&quot;https://www.arduino.cc/en/Tutorial/AnalogReadSerial&quot; rel=&quot;nofollow noreferrer&quot;&gt;Analog Read Serial&lt;/a&gt;&quot; to learn how to output data to the computer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You need a laser diode &lt;a href=&quot;https://www.adafruit.com/product/1054&quot; rel=&quot;nofollow noreferrer&quot;&gt;like this one&lt;/a&gt;. It should be powered (or at least turned on/off) by the Arduino. Because you will need to do measurements with the laser on and off to know how much light is ambient light and how much light is coming from your laser.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To sense the light intensity of the laser after it travelled trough the air, you can use a &lt;a href=&quot;https://www.adafruit.com/product/161&quot; rel=&quot;nofollow noreferrer&quot;&gt;photoresistor&lt;/a&gt; to make it simple and cheap, or a luminosity sensor like &lt;a href=&quot;https://www.adafruit.com/product/1980&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one&lt;/a&gt;. You can find here &lt;a href=&quot;https://learn.adafruit.com/adafruit-tsl2591&quot; rel=&quot;nofollow noreferrer&quot;&gt;a tutorial and example code&lt;/a&gt; to wire and read data from that sensor into your Arduino.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then you need to calibrate the sensor, and it will be challenging for this project. You will need to put the system in the outdoors, measure the visibility by finding out the distance to the further object you can see, and record the reading of your Arduino. The reading would be the difference between the luminosity with the laser on and off.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;After you have many calibration points over a wide range of visibilities, you can plot visibility vs reading and hopefully the points will follow a nice pattern that you can then fit with a suitable function (a line, a polynomial or logarithmic function), and then code that function into the Arduino so it can output the actual visibility.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the pattern isn't nice, you will need to find ways to make the reading more accurate and sensible to changes in visibility. Some options for that (that you should consider also in your initial design) are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Increase the travel length of the laser through the air.&lt;/li&gt;&#xA;&lt;li&gt;Use a blue laser, as blue light is absorbed quickly in low visibility conditions.&lt;/li&gt;&#xA;&lt;li&gt;Use a hood with black interior (like the photographic lens hoods) around the sensor to minimize the contribution to ambient light.&lt;/li&gt;&#xA;&lt;li&gt;Use a luminosity sensor with larger resolutions (12 or 16 bits)&lt;/li&gt;&#xA;&lt;li&gt;Make sure the laser voltage is stable.&lt;/li&gt;&#xA;&lt;li&gt;Make sure the laser (and mirror if you use one) have a good and stable alignment. &lt;/li&gt;&#xA;&lt;li&gt;Make sure readings are not affected by temperature or compensate otherwise.&lt;/li&gt;&#xA;&lt;li&gt;Get multiple readings and take the median.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;There is an Arduino Stack Exchange where you can find help if you need help to make the sensors to work or problems with the coding. However, there are tons of online resources and tutorials, so I'm sure you will find answers to all your questions.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-04-04T18:49:16.770" LastActivityDate="2019-04-04T18:49:16.770" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16642" PostTypeId="2" ParentId="16628" CreationDate="2019-04-04T03:13:29.923" Score="1" Body="&lt;p&gt;I found this on the &lt;a href=&quot;https://water.usgs.gov/edu/urbaneffects.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS website&lt;/a&gt;. It states the effect of increased pavement coverage due to urbanization is to reduce the recharge rate of ground water, because the water is diverted elsewhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, with urbanization comes the use of storm water drains. The rain water that would have soaked into the ground and recharged the ground water is diverted to streams via the storm water systems (pipes and channels) which can result in flooding elsewhere.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-04-04T03:13:29.923" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16646" PostTypeId="1" CreationDate="2019-04-04T11:51:30.737" Score="1" ViewCount="208" Body="&lt;p&gt;Where is the least-polluted place on Earth that people are permanently resident and bring up children?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Adding detail per request in comments: I’m asking about all forms of pollution, at the local (town/village/hamlet) level. Anywhere that people live where it’s not so remote or climactically unfriendly that it’s unfeasible to bring up children (eg the North Pole).&lt;/p&gt;&#xA;" OwnerUserId="1336" LastEditorUserId="1336" LastEditDate="2019-04-04T17:02:05.507" LastActivityDate="2019-04-04T17:02:05.507" Title="Where is the least polluted place to live on earth?" Tags="|pollution|" AnswerCount="0" CommentCount="5" ClosedDate="2019-04-05T09:31:50.543" ContentLicense="CC BY-SA 4.0" />
  <row Id="16649" PostTypeId="2" ParentId="16640" CreationDate="2019-04-04T20:21:51.907" Score="4" Body="&lt;p&gt;Im am currently doing my masters in geophysics (last semester) and before that I did a bachelor in geoscience. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I assume by layers you mean the crust, the mantle and the core. &#xA;These all have different composition and also different densities. But the earth rotates as a whole, not the individual layers, all layers have the same angular velocity. That means they all make one rotation per day. &#xA;These layers are also not the perfect boundaries we like to imagine, but more a change in properties around a finite depth. This depth can even change at different places.&lt;/p&gt;&#xA;" OwnerUserId="15592" LastActivityDate="2019-04-04T20:21:51.907" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16650" PostTypeId="2" ParentId="16640" CreationDate="2019-04-04T20:57:59.413" Score="5" Body="&lt;p&gt;The inner core rotates slightly faster than the rest of the planet. &lt;a href=&quot;https://www.nationalgeographic.org/encyclopedia/core/&quot; rel=&quot;noreferrer&quot;&gt;This&lt;/a&gt; passage from National Geographic explains: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The liquid outer core separates the inner core from the rest of the Earth, and as a result, the inner core rotates a little differently than the rest of the planet. It rotates eastward, like the surface, but it’s a little faster, making an extra rotation about every 1,000 years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I have never read anything to suggest, however, that the other layers of the Earth rotate at differenct velocities.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2019-04-04T20:57:59.413" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16651" PostTypeId="1" CreationDate="2019-04-05T03:13:30.917" Score="3" ViewCount="60" Body="&lt;p&gt;The BBC News article &lt;a href=&quot;https://www.bbc.com/news/science-environment-47817510&quot; rel=&quot;nofollow noreferrer&quot;&gt;Antarctic: No role for climate in Halley iceberg splitting&lt;/a&gt; says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;With no-one on the ice surface, notice of any breakaway will have to come from &lt;strong&gt;automated in-situ instrumentation&lt;/strong&gt; and from spacecraft observations.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;What (if any) &amp;quot;in-situ instrumentation&amp;quot; is on the Brunt Ice Shelf that will detect its splitting and breaking away?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/13251/6031&quot;&gt;This answer&lt;/a&gt; to my question &lt;em&gt;The giant 6,000 km2 iceberg A-68; will ground-truth telemetry supplement satellite tracking data?&lt;/em&gt; suggests that there was no GPS tracking of iceberg A-68 (which still surprises me!) but does the Brunt Ice Shelf have GPS and automatic telemetry?&lt;/p&gt;&#xA;&lt;p&gt;Note: The BBC article contains the following possibly helpful links:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://projects.enveo.at/Brunt/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This remote-sensing data is processed by the ENVEO (Environmental Earth Observation) company&lt;/a&gt;, in Innsbruck, Austria; and ENVEO staff are co-authors on &lt;a href=&quot;https://www.the-cryosphere-discuss.net/tc-2019-46/&quot; rel=&quot;nofollow noreferrer&quot;&gt;a new paper with the Northumbria team that is under review in The Cryosphere journal&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Q3OMU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Q3OMU.png&quot; alt=&quot;Brunt Ice Shelf BBC&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: NASA, LandSat, USGS, &lt;a href=&quot;https://www.bbc.com/news/science-environment-47817510&quot; rel=&quot;nofollow noreferrer&quot;&gt;BBC&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2022-01-31T01:16:33.427" LastActivityDate="2022-01-31T09:31:32.310" Title="What (if any) &quot;in-situ instrumentation&quot; is on the Brunt Ice Shelf that will detect its splitting and breaking away?" Tags="|glaciology|remote-sensing|antarctica|gnss|gps|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16652" PostTypeId="1" AcceptedAnswerId="22643" CreationDate="2019-04-05T03:40:52.780" Score="6" ViewCount="159" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Rayleigh_scattering&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rayleigh scattering&lt;/a&gt; (mostly) results in a blue sky (&lt;a href=&quot;https://en.wikipedia.org/wiki/Diffuse_sky_radiation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Diffuse_sky_radiation&lt;/a&gt;) as seen from Earth's surface. Go up in a plane to cruise altitude and the sky gets noticeably blue-er, and then darker.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The scale height of the Earth's atmosphere is roughly 8 kilometers, which means that half of Earth's atmosphere's mass is below about 5.5 km, again roughly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Does half of a blue sky's blue light come from this lower 5.5 kilometers as well, or does the effect vary with density such that a disproportionate amount is coming from higher altitudes?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Origin of this question is from comments below &lt;a href=&quot;https://space.stackexchange.com/a/35306/12102&quot;&gt;@Ingolifs' answer&lt;/a&gt; to &lt;em&gt;Puzzler: help understanding these amazing Curiosity eclipse GIFs&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2021-07-26T10:19:24.363" LastActivityDate="2021-08-01T23:10:57.040" Title="Where does the sky's blueness come from; at what altitudes is it being produced?" Tags="|atmosphere|atmospheric-optics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16653" PostTypeId="1" AcceptedAnswerId="16738" CreationDate="2019-04-05T04:28:32.637" Score="1" ViewCount="138" Body="&lt;p&gt;The BBC News article &lt;a href=&quot;https://www.bbc.com/news/science-environment-47817510&quot; rel=&quot;nofollow noreferrer&quot;&gt;Antarctic: No role for climate in Halley iceberg splitting&lt;/a&gt; says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;With no-one on the ice surface, notice of any breakaway will have to come from &lt;strong&gt;automated in-situ instrumentation&lt;/strong&gt; and from spacecraft observations.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The image below shows the &lt;em&gt;current location&lt;/em&gt; of &lt;a href=&quot;https://en.wikipedia.org/wiki/Halley_Research_Station&quot; rel=&quot;nofollow noreferrer&quot;&gt;Halley Research Station&lt;/a&gt; relative to &quot;&lt;strong&gt;Chasm One&lt;/strong&gt;&quot;. I like that name. It reminds me of &lt;a href=&quot;https://en.wikipedia.org/wiki/SpaceShipOne&quot; rel=&quot;nofollow noreferrer&quot;&gt;SpaceShipOne&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Public_Enemy_No._1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Public Enemy No. 1&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is &quot;Chasm One&quot; an &quot;official&quot; name for the feature? How was the term coined? Will there be a new Chasm One someday, or will the name be retired after this one splits?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Q3OMU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Q3OMU.png&quot; alt=&quot;Brunt Ice Shelf and Chasm One BBC&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: NASA, LandSat, USGS, &lt;a href=&quot;https://www.bbc.com/news/science-environment-47817510&quot; rel=&quot;nofollow noreferrer&quot;&gt;BBC&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="2470" LastEditDate="2021-07-06T06:59:08.940" LastActivityDate="2021-07-06T06:59:08.940" Title="Is &quot;Chasm One&quot; the really the name of this feature on the Brunt Ice Shelf?" Tags="|glaciology|terminology|antarctica|ice-shelf|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16654" PostTypeId="1" AcceptedAnswerId="16658" CreationDate="2019-04-05T06:27:11.750" Score="2" ViewCount="305" Body="&lt;p&gt;I have a output of 3 models of CMIP5, they are CCSM4, IPSL and MPI. I have two scenarios RCP 2.6 and RCP 8.5 for each model. I want to know that how can I create a multi model ensemble from these 3 models? Because when I plot different graphs of various  variables, I end up with so many lines. So is multi model a sensible approach? But how can I create a multi model of these models in R? and what is the science behind multi model ensemble of cmip5 models  (because I have seen in many research papers that authors have taken ensemble means). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Suppose I have 3 lines of each model in a graph, and then showing the mean of all lines by ONE line, is that considered as an ensemble?&lt;/p&gt;&#xA;" OwnerUserId="15594" LastActivityDate="2019-04-05T16:34:44.090" Title="How can I create multi model ensemble from output of 3 CMIP5 models?" Tags="|models|atmosphere-modelling|climate-models|" AnswerCount="1" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16655" PostTypeId="1" AcceptedAnswerId="16659" CreationDate="2019-04-05T11:03:57.657" Score="5" ViewCount="182" Body="&lt;p&gt;The question was inspired by an answer to &lt;a href=&quot;https://history.stackexchange.com/questions/51958/approximately-how-much-travel-time-was-saved-by-the-opening-of-the-suez-canal-in&quot;&gt;this question&lt;/a&gt; on History SE, which referred to the &quot;at times enormous waves&quot; at the Cape of Good Hope in South Africa, and the even more &quot;treacherous&quot; passage around Cape Horn.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is the sea so hard to navigate at the southern extremities of the land masses.?Cape Horn, with a latitude in the high 50's, is easy to understand, but the Cape of Good Hope is in the 30s. Yet from what I understand, &quot;navigability&quot; does not extend far south of the Cape of Good Hope.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is southern Australia and Tasmania (in the 40s latitudes) similarly hard to navigate? Would it be fore the same reasons?&lt;/p&gt;&#xA;" OwnerUserId="42" LastActivityDate="2019-04-05T16:57:19.020" Title="Why are the seas difficult to navigate at the &quot;southern edge&quot; of land?" Tags="|oceanography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16658" PostTypeId="2" ParentId="16654" CreationDate="2019-04-05T16:34:44.090" Score="2" Body="&lt;h1&gt;What is an ensemble?&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;An ensemble is a &lt;em&gt;set of several model simulations&lt;/em&gt;. One simulation of an ensemble is denoted as &lt;em&gt;ensemble member&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A &lt;em&gt;multi-model ensemble&lt;/em&gt; is an ensemble created by simulations with several models (e.g. each model is run twice).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alternatively, one might create an ensemble by performing several simulations performed with one model. Each simulation is disturbed by some noise so that the model produces slightly different result for each model run. We denote each run as a &lt;em&gt;realization&lt;/em&gt;. The generation of the appropriate noise is model dependent (the results should cover the natural variability) and a scientific topic itself. Additionally, we might use other initial conditions or different physical parameterizations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The individual simulations of a CMIP5 model are identified according to the &lt;em&gt;rip&lt;/em&gt; nomenclature: rXiYpZ (r: realization; i: initialisation; p: physics; X, Y, and Z are integers), e.g. r12i1p1 or r1i1p1. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is also explained here: &lt;a href=&quot;https://portal.enes.org/data/enes-model-data/cmip5/datastructure&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://portal.enes.org/data/enes-model-data/cmip5/datastructure&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Summarizing ensemble simulations&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;If you calculate the mean of your models runs, you call it the &quot;ensemble mean&quot;. If you calculate the standard deviations, you call it &quot;ensemble standard deviation&quot;. The &quot;ensemble&quot; prefix just means that you calculated the mean/std.dev./etc. from an ensemble of simulations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Example: &lt;a href=&quot;http://ar5-syr.ipcc.ch/topic_futurechanges.php#figure_2_1&quot; rel=&quot;nofollow noreferrer&quot;&gt;This plot&lt;/a&gt; of the 5th Assessment Report of the IPCC (synthesis report of Topic 2 - &lt;em&gt;Future Climate Changes, Risks and Impacts&lt;/em&gt;, online version) shows the ensemble mean (solid thick colored lines) and the space covered by the 5% to 95% percentiles (shaded area).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jk0Hv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jk0Hv.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please have a look here for the caption and more details: &lt;a href=&quot;http://ar5-syr.ipcc.ch/topic_futurechanges.php#figure_2_1&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://ar5-syr.ipcc.ch/topic_futurechanges.php#figure_2_1&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2019-04-05T16:34:44.090" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16659" PostTypeId="2" ParentId="16655" CreationDate="2019-04-05T16:57:19.020" Score="11" Body="&lt;p&gt;Fetch.  The longer the wind has to act on the water the larger and more developed the waves become, &lt;a href=&quot;https://oceanservice.noaa.gov/education/kits/currents/03coastal1.html&quot; rel=&quot;noreferrer&quot;&gt;see this site from the NOAA&lt;/a&gt;.  If you look at the southern portion of our planet you will note that there are few land masses to affect the wind or the wave development.  In the &lt;a href=&quot;https://en.wikipedia.org/wiki/Prevailing_winds&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia entry about prevailing winds&lt;/a&gt; you can see that the Southern Westerly winds are only affected by the Cape of Good Hope, Cape Horn, and to a lesser extent Australia.  Contrast this to the Northern hemisphere where North America, Europe and Asia divide the seas into smaller isolated sections.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are additional factors involved particularly around the capes.  If you look at the prevailing ocean currents, &lt;a href=&quot;https://worldoceanreview.com/en/wor-1/climate-system/great-ocean-currents/2/&quot; rel=&quot;noreferrer&quot;&gt;see global map on this site&lt;/a&gt; you will see there are strong currents, driven by the wind, around the southern pole region.  At the capes, these currents become more chaotic and lead to eddies.  Sometimes the eddies make the current flow against the wind.  This results in even larger and less predictable sea states.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2019-04-05T16:57:19.020" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16671" PostTypeId="1" AcceptedAnswerId="16672" CreationDate="2019-04-07T04:14:27.090" Score="4" ViewCount="167" Body="&lt;p&gt;Although parts of northern Minnesota have bedrock exposed at the surface (especially in the Boundary Waters area and along the short of Lake Superior), the more usual situation here is for the bedrock to be buried very deeply indeed - with, in places, more than a hundred meters of soil overlying it, according to &lt;a href=&quot;https://conservancy.umn.edu/bitstream/handle/11299/60080/umn22629%5b1%5d.pdf?sequence=1&amp;amp;isAllowed=y&quot; rel=&quot;nofollow noreferrer&quot;&gt;this map&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This doesn't make sense to me; the whole area was buried under an ice sheet during the most recent glaciation, and the hundreds of meters of moving ice would have scraped everything down to bedrock (and scraped off large amounts of the bedrock itself) and prevented any new soil from forming until the ice sheet retreated.  Northern Minnesota has only been ice-sheet-free for a blink of an eye, geologically speaking - how did hundreds of meters of soil manage to form in such a short period of time?&lt;/p&gt;&#xA;" OwnerUserId="12549" LastActivityDate="2019-04-08T23:14:32.833" Title="Why is the bedrock buried so deeply in much of northern Minnesota?" Tags="|earth-history|soil|glaciation|bedrock|united-states|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16672" PostTypeId="2" ParentId="16671" CreationDate="2019-04-07T10:12:33.920" Score="2" Body="&lt;p&gt;Biological time scale is not the same as geological time scale, and permanent ice retreated from Minessota around 18.000 years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A search on Google took me to this website, where it says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The time needed to form a soil depends on the latitude:&lt;/p&gt;&#xA;  &#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;in environments characterized by a mild climate, it takes 200-400 years to form 1 cm of soil.&lt;/li&gt;&#xA;  &lt;li&gt;in wet tropical areas soil formation is faster, as it takes 200 years.&lt;/li&gt;&#xA;  &lt;li&gt;in order to accumulate enough substances to make a soil fertile it takes 3000 years.&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;  &#xA;  &lt;p&gt;Source: &lt;a href=&quot;http://www.eniscuola.net/en/argomento/soil/soil-formation/how-long-does-it-take-to-form/&quot; rel=&quot;nofollow noreferrer&quot;&gt;eniscuola.net&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That doesn't mean you need 20.000 years to make 100 cm (one meter) of soil, as said in this blog post.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Many soils  formed after glaciers retreated are only about 10,000 to&#xA;  20,000 years old, but have thick topsoils.&quot;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: &lt;a href=&quot;https://soilsmatter.wordpress.com/2013/08/29/soil-formation/&quot; rel=&quot;nofollow noreferrer&quot;&gt;soilsmatter2011, Wordpress&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The reason why thick soil is formed in that short time scale is, once vegetation is estalished, the process accelerates because tree roots break the rock and contribute to form new soil profiles.&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-04-07T11:17:57.937" LastActivityDate="2019-04-07T11:17:57.937" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16673" PostTypeId="2" ParentId="16606" CreationDate="2019-04-07T18:28:54.760" Score="3" Body="&lt;p&gt;As Camilo mentioned in the comments, “carbon neutral” in this context means zero net carbon emissions.  This is the gross anthropogenic carbon emissions (fossil fuel burning and land use change) minus the carbon absorbed &lt;em&gt;through managed practices&lt;/em&gt;.  That distinction is important; you don’t include the carbon absorbed by the ocean and land through &lt;em&gt;natural&lt;/em&gt; processes to offset gross emissions in the calculation.&#xA;Since 2010, the UN Environment Programme has published an “Emissions Gap” report each year that includes some relevant emissions numbers:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In 2017 greenhouse gas (GHG) emissions - excluding emissions from land-use change - reached a record 49.2 GtCO2e... Emissions from land-use change... added another 4.2 GtCO2, bringing the total to 53.5 GtCO2e.&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.unenvironment.org/resources/emissions-gap-report-2018&quot; rel=&quot;nofollow noreferrer&quot;&gt;UNEP Emissions Gap Report 2018&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The following is a nice schematic of various negative emission technologies (NETs) that could be used as mitigation in the overall budget:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HPdgp.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HPdgp.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: Smith et al (2016) “Biophysical and economic limits to negative CO2 emissions”, &lt;a href=&quot;https://www.nature.com/articles/nclimate2870&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/nclimate2870&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Carbon capture and storage (CCS) is done at the point of burning fossil fuels, so reduces gross fossil emissions. Panel (g) is called LULUCF (Land Use, Land Use Change and Forestry) in the Emissions Gap reports and AFOLU (Agriculture, Forestry and Other Land Use) in the IPCC 1.5 Special Report, and that is effectively the +4.2 GtCO2e/year quoted above.  The idea is that in the future land management will have to change to turn managed land from a net source to a net sink of GHGs.  As for Bio-energy Carbon Capture Systems (BECCS), the current levels are about zero, although there are a dozen or so demonstrator projects totalling about 0.001 GtCO2/year.  So at the moment it barely makes a dent in the overall budget, but mitigation scenarios require it rising to an order of 10 GtCO2/year by 2050:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vQziD.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vQziD.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The energy production from the use of BECCS over time in a range of mitigation scenarios.&lt;/p&gt;&#xA;&lt;p&gt;Source: van Vuuren et al (2018) “Alternative pathways to the 1.5 °C target reduce the need for negative emission technologies”, &lt;a href=&quot;https://www.nature.com/articles/s41558-018-0119-8&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/s41558-018-0119-8&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The IPCC special report also has a nice schematic of how NETs contribute to emissions scenarios.  Although there's no timescale on the schematic, most of the actual scenarios don't show any notable BECCS until 2030.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xsgkk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xsgkk.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Figure 2.5 | Evolution and break down of global anthropogenic CO2 emissions until 2100&lt;/p&gt;&#xA;&lt;p&gt;Source: Rogelj et al (2018) &amp;quot;Mitigation Pathways Compatible with 1.5°C in the Context of Sustainable Development&amp;quot;, Chapter 2 of the IPCC &lt;a href=&quot;https://www.ipcc.ch/sr15&quot; rel=&quot;nofollow noreferrer&quot;&gt;Special Report on Global Warming of 1.5°C&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="106" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-04-08T10:00:43.723" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16674" PostTypeId="1" CreationDate="2019-04-07T20:13:43.900" Score="2" ViewCount="856" Body="&lt;p&gt;I'm not specialist in hydrology, and I  would be very grateful if you answer my question: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is flow accumulation in hydrology?&#xA;Why algorithms used to calculate it over a raster DEM don't take rainfall rate into consideration?&#xA;For example when I use richdem python library to plot flow accumulation what is the range and unit of values shown ? &lt;/p&gt;&#xA;" OwnerUserId="15360" LastActivityDate="2019-04-09T14:21:05.870" Title="Hydrology- flow accumulation" Tags="|geophysics|hydrology|fluid-dynamics|python|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16676" PostTypeId="1" AcceptedAnswerId="16788" CreationDate="2019-04-08T08:15:42.443" Score="4" ViewCount="889" Body="&lt;h2&gt;Question&lt;/h2&gt;&#xA;&lt;p&gt;When discussing &amp;quot;PM2.5&amp;quot;, is there any standardized understanding of which particles are or are not included?&lt;/p&gt;&#xA;&lt;p&gt;Is it everything that's 2.5 microns and smaller? Or Everything &lt;em&gt;between&lt;/em&gt; 2.5 and 0.1 microns?&lt;/p&gt;&#xA;&lt;p&gt;Likewise does PM10 include all of PM2.5?&lt;/p&gt;&#xA;&lt;p&gt;And by what method is &amp;quot;size&amp;quot; specified? Is this an aerodynamic size from some kind of inertial impactor configuration (virtual or real), or an optical size from scattering, or something else?&lt;/p&gt;&#xA;&lt;h2&gt;Background&lt;/h2&gt;&#xA;&lt;p&gt;PM2.5 and other classes of particulates are a &amp;quot;hot topic&amp;quot; now. From Wikipedia's &lt;a href=&quot;https://en.wikipedia.org/wiki/Particulates#Size,_shape_and_solubility_matter&quot; rel=&quot;nofollow noreferrer&quot;&gt;Particulates; size, shape and solubility matter&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;[...]The 10-micrometer size does not represent a strict boundary between respirable and non-respirable particles, but has been agreed upon for monitoring of airborne particulate matter by most regulatory agencies. Because of their small size, &lt;strong&gt;particles on the order of 10 micrometers or less (coarse particulate matter, PM10)&lt;/strong&gt; can penetrate the deepest part of the lungs such as the bronchioles or alveoli; when asthmatics are exposed to these conditions it can trigger bronchoconstriction.&lt;/p&gt;&#xA;&lt;p&gt;Similarly, so called fine particulate matter (PM2.5), tend to penetrate into the gas exchange regions of the lung (alveolus), and very small particles (ultrafine particulate matter, PM0.1) may pass through the lungs to affect other organs. Penetration of particles is not wholly dependent on their size; shape and chemical composition also play a part. To avoid this complication, simple nomenclature is used to indicate the different degrees of relative penetration of a PM particle into the cardiovascular system. Inhalable particles penetrate no further than the bronchi as they are filtered out by the cilia. Thoracic particles can penetrate right into terminal bronchioles whereas PM0.1, which can penetrate to alveoli, the gas exchange area, and hence the circulatory system are termed respirable particles. In analogy, the inhalable dust fraction is the fraction of dust entering nose and mouth which may be deposited anywhere in the respiratory tract. The thoracic fraction is the fraction that enters the thorax and is deposited within the lung's airways. The respirable fraction is what is deposited in the gas exchange regions (alveoli).&lt;/p&gt;&#xA;&lt;p&gt;The smallest particles, less than 100 nanometers (nanoparticles), may be even more damaging to the cardiovascular system. Nanoparticles can pass through cell membranes and migrate into other organs, including the brain. Particles emitted from modern diesel engines (commonly referred to as Diesel Particulate Matter, or DPM) &lt;strong&gt;are typically in the size range of 100 nanometers (0.1 micrometer).&lt;/strong&gt; [...]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;From AirNow.gov's &lt;a href=&quot;https://airnow.gov/index.cfm?action=aqibasics.particle&quot; rel=&quot;nofollow noreferrer&quot;&gt;Particle Pollution (PM)&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Coarse dust particles (PM10) are 2.5 to 10 micrometers in diameter&lt;/strong&gt;. Sources include crushing or grinding operations and dust stirred up by vehicles on roads.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Fine particles (PM2.5) are 2.5 micrometers in diameter or smaller&lt;/strong&gt;, and can only be seen with an electron microscope. Fine particles are produced from all types of combustion, including motor vehicles, power plants, residential wood burning, forest fires, agricultural burning, and some industrial processes&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;However, EPA.gov's &lt;a href=&quot;https://www.epa.gov/pm-pollution/particulate-matter-pm-basics#PM&quot; rel=&quot;nofollow noreferrer&quot;&gt;Particulate Matter (PM) Basics; What is PM, and how does it get into the air?&lt;/a&gt; says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;PM10:&lt;/strong&gt; inhalable particles, with diameters that are &lt;strong&gt;generally 10 micrometers and smaller&lt;/strong&gt;; and&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;PM2.5:&lt;/strong&gt; fine inhalable particles, with diameters that are &lt;strong&gt;generally 2.5 micrometers and smaller.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JIdjz.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JIdjz.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.epa.gov/pm-pollution/particulate-matter-pm-basics#PM&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-04-22T09:52:34.300" Title="Which particles are classified as PM2.5? How exactly is this defined?" Tags="|atmosphere|air-pollution|terminology|instrumentation|pm2.5|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16677" PostTypeId="2" ParentId="10178" CreationDate="2019-04-08T11:38:07.523" Score="1" Body="&lt;p&gt;The main difference is micro-texture. You cannot differentiate between both from a picture or a view, you need to go to the field and:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Break the rock with your hammer to observe&#xA;the rock in fresh-cut.&lt;/li&gt;&#xA;&lt;li&gt;Add a bit of water to remove dust and correctly observe the colour and texture of the rock.&lt;/li&gt;&#xA;&lt;li&gt;Finally use a magnifying glass to determine what the rock is made&#xA;of.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;You should differentiate them as sandstones are always composed of grains. The texture is always grain-supported.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Limestones are composed of calcite. The texture use to be different, but it migth have also carbonated grains. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BSGJY.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BSGJY.jpg&quot; alt=&quot;Dunham classification of carbonates&quot;&gt;&lt;/a&gt;&#xA;&lt;strong&gt;Rebooted Dunham classification of carbonates&lt;/strong&gt;. Image from: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:The_Rebooted_Dunham_Classification.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;commons.wikimedia.org&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can differentiate them in all cases unless you have a grainstone limestone with sand-grade grains (63μm-2mm). Then you need to identify the carbonated grains that can be fossils or oolites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PZatX.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PZatX.jpg&quot; alt=&quot;Oolites&quot;&gt;&lt;/a&gt;&#xA;&lt;strong&gt;Oolites&lt;/strong&gt;. Image from: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:OoidSurface01.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;commons.wikimedia.org&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fossils are clearly differenciated from sandstone grains with a magnifying glass, and oolites have a concentrical structure as shown in the picture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alternatively you can use dissolved hydrochloric acid or vinegar. As limestones are composed by calcite you will see a reaction, but you could also see the reaction on a sandstone if it has carbonated components. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once you have determined the composition of a rock bed you can do the cartography at the lab with a stereoscope and aerial pictures or do it at the field again painting the limits on your map.&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-04-08T13:53:02.270" LastActivityDate="2019-04-08T13:53:02.270" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16678" PostTypeId="1" AcceptedAnswerId="16681" CreationDate="2019-04-08T12:00:43.297" Score="3" ViewCount="1675" Body="&lt;p&gt;According to this article, a mini ice age could hit Earth by 2030&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.scienceinsanity.com/2019/01/a-mini-ice-age-could-hit-earth-by-2030.html?fbclid=IwAR3MWKu2AuU_1DGOLUIRLEZSa9zJ5I8GO94WY5RLo2t090C8cZkNuLE8Big&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mini Ice Age could hit Earth by 2030&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and according to this video &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;blockquote&gt;&#xA;    &lt;p&gt;NASA admits mini ice age coming faster than anticipated. &lt;/p&gt;&#xA;  &lt;/blockquote&gt;&#xA;  &#xA;  &lt;p&gt;All continents are now showing signs of cooling&lt;/p&gt;&#xA;  &#xA;  &lt;blockquote&gt;&#xA;    &lt;p&gt;Mini Ice Age by 2021 not 2024, Every Continent Will be Affected&lt;/p&gt;&#xA;  &lt;/blockquote&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=1H7uSCA_ZSE&amp;amp;fbclid=IwAR0491N0EAgl7awwp5k6xk1iV81A-ir0BKV_TnBOOTOyl-IGsNjj3CsAbSc&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mini ice age by 2021 not 2024&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are we going to enter a mini ice age in the next decade, and if so, when?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastEditorUserId="9635" LastEditDate="2019-08-21T18:00:49.797" LastActivityDate="2020-06-24T23:34:04.543" Title="Are we going to enter a mini ice age by 2030?" Tags="|climate-change|ice-age|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16679" PostTypeId="2" ParentId="16674" CreationDate="2019-04-08T13:54:23.150" Score="5" Body="&lt;p&gt;The flow accumulation algorithm essentially determines the upstream contributing area of every grid cell; in other words, what area or how many other cells will drain into a given cell. The flow accumulation algorithm is independent of rainfall as it simply determines which areas drain where, which will later be used to determine how much water actually flows based on the rainfall event and the area on which the rain actually occurs. However, the first step is just to figure out the flow directions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The flow accumulation is typically done as part of a series of algorithms with a given DEM to determine where the river network exists and what the catchment boundaries are. This type of analysis is required in order to delineate watersheds (i.e. determine where the watershed boundaries are and how large they are) and create the building blocks for a hydrologic model, which is used to simulate the rainfall-runoff response and flows at given points, among other processes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The flow accumulation algorithm typically used is the &lt;a href=&quot;https://jblindsay.github.io/wbt_book/available_tools/hydrological_analysis.html#D8FlowAccumulation&quot; rel=&quot;nofollow noreferrer&quot;&gt;D8 algorithm&lt;/a&gt;, although if you look into the literature there are lots of versions and variations on determining flow accumulation. I am not familiar with the richdem python algorithm, but the units will be some measure of either upstream contributing area or number of upstream units in every grid cell. You will notice that the areas downstream and near outlets of watersheds have higher values, indicating that those areas receive larger contributing areas from the rest of the watershed. The next step in the analysis, likely a flow network tool, will use the grid cells with the largest flow accumulation values to determine the existence of a river network based on high accumulation values (with some value as a threshold).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://pro.arcgis.com/en/pro-app/tool-reference/spatial-analyst/how-flow-accumulation-works.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;ESRI page&lt;/a&gt; has a good discussion on how flow accumulation works as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Examples&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Watershed delineation can be done automatically from a DEM layer, and there are a huge number of tools to do so. Here are some tutorials and guides with GIS software, other tools exist in R or python (as you pointed out).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.trentu.ca/library/sites/default/files/documents/WatershedDelineation_10_2.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;ArcGIS Watershed Delineation Tutorial with Arc 10.2&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://geogeek.xyz/catchment-delineation-with-qgis.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;QGIS Watershed Delineation Example&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that prior to the use of DEM tools, contour maps would be used to delineate watersheds by hand. This is done essentially by drawing outlines which cross contours perpendicularly through high areas, and encompass the watershed. A couple examples of that here for you as well. Note that these will not have flow accumulation since that cannot be done easily by hand, that is only a step using the computational tools.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nrcs.usda.gov/wps/portal/nrcs/detail/nh/technical/?cid=nrcs144p2_015680&quot; rel=&quot;nofollow noreferrer&quot;&gt;US Department of Agriculture Example&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.uwsp.edu/cnr-ap/UWEXLakes/Documents/programs/convention/2015/talks/Thursday%20AM%20Workshops/StacyDehne_WatershedDelineationTechniques_AdvShorelineErosionControlWksp.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Miscellaneous contour example and slides&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8440" LastEditorUserId="8440" LastEditDate="2019-04-09T14:21:05.870" LastActivityDate="2019-04-09T14:21:05.870" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16681" PostTypeId="2" ParentId="16678" CreationDate="2019-04-08T17:41:45.167" Score="10" Body="&lt;p&gt;These claims originate with a &lt;a href=&quot;https://www.researchgate.net/publication/266799418_Prediction_of_Solar_Activity_from_Solar_Background_Magnetic_Field_Variations_in_Cycles_21-23&quot; rel=&quot;noreferrer&quot;&gt;paper&lt;/a&gt; by a mathematician named Valentina Zharkova and others, who studied a correlation between solar magnetic fields and sunspots.  Based on the last three solar cycles, her model predicted that the next several solar cycles will be less intense than typical (i.e. fewer sunspots), which implies lower radiant output.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.iflscience.com/environment/mini-ice-age-hoopla-giant-failure-science-communication/&quot; rel=&quot;noreferrer&quot;&gt;Here&lt;/a&gt; is an article addressing the claims and explaining why it's not something to worry about.  Some key points include:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The paper only addresses solar activity, and does not mention the impact that lower solar radiation would have on earth.  Climate scientists have &lt;a href=&quot;https://www.theguardian.com/environment/climate-consensus-97-per-cent/2013/aug/14/global-warming-solar-minimum-barely-dent&quot; rel=&quot;noreferrer&quot;&gt;looked&lt;/a&gt; at the impact that a Maunder Minimum would have, and found that the cooling effect of reduced solar output is less than the warming effect of increased greenhouse gases, so the net effect is that the earth will continue to warm even if the predictions turn out to be correct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cooling associated with the Maunder Minimum was not entirely due to the lower sunspot numbers.  There is &lt;a href=&quot;https://www.sciencedaily.com/releases/2012/01/120130131509.htm&quot; rel=&quot;noreferrer&quot;&gt;evidence&lt;/a&gt; that massive volcanic eruptions played a significant role in the cooling. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Claims that the earth is already cooling because there may be fewer sunspots 5 or 15 years from now simply make no sense, and  &lt;a href=&quot;https://climate.nasa.gov/vital-signs/global-temperature/&quot; rel=&quot;noreferrer&quot;&gt;global temperature measurements&lt;/a&gt;  clearly show that there is not a cooling trend.  &lt;/p&gt;&#xA;" OwnerUserId="8163" LastActivityDate="2019-04-08T17:41:45.167" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="16684" PostTypeId="2" ParentId="16671" CreationDate="2019-04-08T23:14:32.833" Score="4" Body="&lt;p&gt;As njuffa mentioned I don't believe you are looking at soil 100s of meters deep you are looking at unconsolidated sediments 100s of meters deep.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Depending on the geological process it is possible to deposit 100s of meters of sediments in a very short time.  The conditions for deposition of large amounts of sediments are frequently found during the period of time that the glaciers are melting.  During this time the sides of the glacier end up forming the glacial fluvial terraces and the toe of the glacier often breaks into pieces of ice that the sediment can build around.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This &lt;a href=&quot;http://geo.msu.edu/extra/geogmich/kettle_lakes.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;site&lt;/a&gt; from the Minnesota State University describes the majority of the lakes in Minnesota as Kettle Lakes, which suggests that the tail end of the ice age was a time of significant sediment deposition.  The North Eastern area would have likely be covered by ice while the South Western portions would have been experiencing the deposition of materials from the rapidly melting glaciers.  There is a &lt;a href=&quot;https://en.wikipedia.org/wiki/Glacial_history_of_Minnesota&quot; rel=&quot;nofollow noreferrer&quot;&gt;whole wikipedia site devoted to the glaciation of Minnesota&lt;/a&gt; that describes the events relatively well.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2019-04-08T23:14:32.833" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16685" PostTypeId="1" AcceptedAnswerId="16709" CreationDate="2019-04-09T03:29:46.847" Score="2" ViewCount="421" Body="&lt;p&gt;The screenshot below is from MIT's Erik Velasco's presentation &lt;a href=&quot;http://www.cityu.edu.hk/gcacic/umcc/Erik_Velasco.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Particle exposure and dosage on public transport&lt;/a&gt;. My question is about the small, portable Black Carbon (BC) monitor. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From my reading, Black Carbon refers to mostly carbon particles, mostly produced in natural and anthropogenic combustion processes (e.g. forest fires, vehicles...). Unlike most of the particles that fall into the PM10 and PM2.5 classifications, it seems that a very important fraction of BC comes from very small particles of the order 0.1 microns since they are formed during a short time during combustion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;0.1 micron particles are hard to detect using laser scatterometry since they scatter very weakly compared to the larger particles, and the size of the portable meter shown seems quite small for an advanced scatterometer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; How do small, portable Black Carbon (BC) Monitors work? I believe this one is called a &lt;em&gt;Micro-Aethalometer&lt;/em&gt; in the presentation; what basic principles do they use to quantify BC in the air that fits in such a small form factor? &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;http://www.cityu.edu.hk/gcacic/umcc/Erik_Velasco.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Particle exposure and dosage on public transport&lt;/a&gt;, open image in new window for full size.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0JOHf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0JOHf.jpg&quot; alt=&quot;portable Black Carbon BC measurement Micro-Aethalometer&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;https://pdfs.semanticscholar.org/ce1e/f01eeb66e86acdd90ac0d3bf1a035bf3944f.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Aeroflex: A Bicycle for Mobile Air Quality Measurements&lt;/a&gt;, Bart Elen et al. Sensors 2013, 13, 221-240; doi:10.3390/s130100221 open image in new window for full size.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wRJwy.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wRJwy.jpg&quot; alt=&quot;portable Black Carbon BC measurement Micro-Aethalometer&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2019-04-09T03:58:34.623" LastActivityDate="2019-04-13T13:13:50.157" Title="What is a Micro-Aethalometer; how do portable Black Carbon (BC) Monitors work?" Tags="|air-pollution|instrumentation|particulates|pm2.5|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16686" PostTypeId="5" CreationDate="2019-04-09T03:32:34.823" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2019-04-09T03:32:34.823" LastActivityDate="2019-04-09T03:32:34.823" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16687" PostTypeId="4" CreationDate="2019-04-09T03:32:34.823" Score="0" Body="PM2.5 is one size classification of airborne particulate matter, but has become a popular catch phrase for  any small-sized particulate matter relevant both to atmospheric heating/cooling (as a greenhouse &quot;gas&quot;) due to their high thermal emissivity and sunlight absorption, and as a pollutant with health consequences. Other particle sizes can use this tag as well, including PM10, PM1, PM0.1" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2019-04-09T09:07:50.247" LastActivityDate="2019-04-09T09:07:50.247" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16688" PostTypeId="1" AcceptedAnswerId="16725" CreationDate="2019-04-09T04:41:40.107" Score="23" ViewCount="2400" Body="&lt;p&gt;There is meteoric material falling on the Earth constantly, as well as some protons and other light nuclei from the solar wind as well as from cosmic rays. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the same time Earth's atmosphere looses gas to space, especially the lightest elements like hydrogen and helium. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/16577/6031&quot;&gt;Where does molecular hydrogen in the atmosphere come from?&lt;/a&gt; is currently unanswered.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Does one process dominate the rate of change of Earth's mass? Is Earth getting heavier or lighter?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2024-04-05T14:01:47.847" Title="Is Earth getting heavier or lighter?" Tags="|atmosphere|solar-terrestrial-physics|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16690" PostTypeId="2" ParentId="14569" CreationDate="2019-04-09T09:37:51.743" Score="1" Body="&lt;p&gt;Wind Vortex on a Lake: the only thing I can visualize is a Tornado on a Lake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Examples: &lt;a href=&quot;https://en.wikipedia.org/wiki/Pine_Lake_tornado&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pine Lake tornado&lt;/a&gt;, &lt;a href=&quot;https://globalnews.ca/news/4346744/tornado-touches-down-at-lake-of-the-prairies/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake of the prairies Tornado&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Technically speaking, a breeze/wind cannot be contained within a Lake, unless the lake is covered by mountain-cliffs or canyons at all sides. Maybe something like &lt;a href=&quot;https://twistedsifter.com/2013/04/hidden-beach-las-marietas-islands-mexico/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Marietas Island's hidden beach&lt;/a&gt; or &lt;a href=&quot;https://twistedsifter.com/2012/08/melissani-cave-kefalonia-greece/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Melissani Cave&lt;/a&gt;, but much larger would sustain a self contained breeze.&lt;/p&gt;&#xA;" OwnerUserId="11793" LastEditorUserId="11793" LastEditDate="2019-04-09T10:15:55.303" LastActivityDate="2019-04-09T10:15:55.303" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16692" PostTypeId="5" CreationDate="2019-04-09T10:23:12.480" Score="0" Body="&lt;p&gt;Transfer of heat/energy through Electromagnetic waves Radiation (EMF)&lt;/p&gt;&#xA;" OwnerUserId="11793" LastEditorUserId="11793" LastEditDate="2019-04-13T10:41:18.070" LastActivityDate="2019-04-13T10:41:18.070" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16693" PostTypeId="4" CreationDate="2019-04-09T10:23:12.480" Score="0" Body="Transfer of heat/energy through Electromagnetic waves Radiation (EMF)" OwnerUserId="11793" LastEditorUserId="11793" LastEditDate="2019-04-13T10:41:13.743" LastActivityDate="2019-04-13T10:41:13.743" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16694" PostTypeId="1" AcceptedAnswerId="16728" CreationDate="2019-04-09T12:02:30.287" Score="1" ViewCount="58" Body="&lt;p&gt;The question in Chemistry SE &lt;a href=&quot;https://chemistry.stackexchange.com/q/112398/16035&quot;&gt;What is the crystal structure of bismuth oxyhydroxyphosphate (BOHP)?&lt;/a&gt; is about a catalyst synthesized by accident. A link in &lt;a href=&quot;https://chemistry.stackexchange.com/questions/112398/what-is-the-crystal-structure-of-bismuth-oxyhydroxyphosphate-bohp?noredirect=1#comment211511_112398&quot;&gt;this comment&lt;/a&gt; points to the page &lt;a href=&quot;https://www.mindat.org/min-3329.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.mindat.org/min-3329.html&lt;/a&gt; which is for the mineral petitjeanite, or &lt;span class=&quot;math-container&quot;&gt;$\ce{Bi3(PO4)2O(OH)}$&lt;/span&gt;. There are about 38 photos available there, and there seems to be quite a diverse range of appearances to my untrained eye.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was wondering if a drawing or computer-generated image of a unit cell for petitjeanite would exist in any database or website for mineralogy and crystal structures, something like those shown in these questions &lt;a href=&quot;https://chemistry.stackexchange.com/q/73755/16035&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;https://chemistry.stackexchange.com/q/71564/16035&quot;&gt;2&lt;/a&gt;, &lt;a href=&quot;https://chemistry.stackexchange.com/q/73254/16035&quot;&gt;3&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Should one assume that the mineral petitjeanite and the chemical discussed in the recent Chemical &amp;amp; Engineering News article &lt;a href=&quot;https://cen.acs.org/environment/persistent-pollutants/Photocatalyst-shreds-drinking-water-contaminant/96/i36&quot; rel=&quot;nofollow noreferrer&quot;&gt;Photocatalyst shreds drinking water contaminant PFOA&lt;/a&gt; are probably the same crystal configuration and unit cell, or can there be some variety?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The paper also includes this SEM image of microcrystals of the &quot;inadvertently produced bismuth oxyhydroxyphosphate (BOHP).&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BV1sI.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BV1sI.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The accidentally synthesized BOHP (shown) can break down the toxic industrial contaminant PFOA faster than any other photocatalyst. Credit: Environ. Sci. Technol. Lett.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2019-04-09T12:10:15.063" LastActivityDate="2019-04-13T16:13:21.040" Title="What does the unit cell of petitjeanite look like?" Tags="|mineralogy|crystals|crystallography|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16695" PostTypeId="1" CreationDate="2019-04-09T14:46:44.300" Score="3" ViewCount="364" Body="&lt;p&gt;I've got a question about calculation of great circles in Cartesian coordinates:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it possible to compute points along a great circle in UTM coordinates, i.e. given two points P1(easting1, northing1) and P2 (easting2, northing2) is there a formula to get waypoints along the geodesic connecting the two (without converting to geographical coordinates and back)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any help is appreciated! Thanks!&lt;/p&gt;&#xA;" OwnerUserId="15623" LastEditorUserId="11908" LastEditDate="2019-04-09T16:30:52.343" LastActivityDate="2019-04-11T18:07:48.433" Title="Great circle in UTM coordinates" Tags="|geography|gis|cartography|geodesy|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16696" PostTypeId="2" ParentId="16695" CreationDate="2019-04-09T16:02:12.583" Score="3" Body="&lt;p&gt;The UTM coordinate system, is a kind of Transverse Mercator projection separated in longitude bands and restricted in latitud extent such that the distortions associated with the projection remain small. Also, the UTM coordinate system is &lt;a href=&quot;https://en.wikipedia.org/wiki/Conformal_map_projection#Conformal&quot; rel=&quot;nofollow noreferrer&quot;&gt;conformal projection&lt;/a&gt;. Therefore, it preserves the angles. That means that within the UTM zones, a straight line in UTM projection is a good approximation great circle over the relatively short distances that could be found in a UTM zone. If you don't need great accuracy, you can just trace the straight line between P1 and P2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following plot shows the maximum deviation that a straight line have from a great circle. In this case P1 the red dot at the Equator and Longitude 3°E, and the maximum deviation is calculated for all points in the displayed box of 6°x6°.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ES05o.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ES05o.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While the differences remain small within distances of few hundred kilometers, bigger differences can be found over larger distances, specially if P1 and P2 are in different UTM zones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If your application requires larger distances, you shouldn't use UTM projection. Alternatively, if you your application require greater accuracy over distances suitable for UTM projection, you can calculate the great circle trajectory, but I don't know any direct formulas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I have used, which I know is not what you are asking for, are some Matlab functions to convert to and from UTM coordinates and another that computes great circle tracks in geographic coordinates:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;function [lat, lon] = greatCircle(P1,P2,N)&#xA;%GREATCIRCLE compute points along the great circle arc connecting points P1&#xA;%and P2&#xA;%   P1, P2 format: [lat,lon]&#xA;%   N: Number of points along the great circle arc&#xA;&#xA;        lat1=P1(1);&#xA;        lon1=P1(2);&#xA;&#xA;        lat2=P2(1);&#xA;        lon2=P2(2);&#xA;&#xA;        lon12=lon2-lon1;&#xA;&#xA;        a1=atan2d(cosd(lat2).*sind(lon12),(cosd(lat1)*sind(lat2)-sind(lat1)*cosd(lat1).*cosd(lon12)));&#xA;        %a2=atan2d(cosd(lat1).*sind(lon12),(-cosd(lat2)*sind(lat1)+sind(lat2)*cosd(lat1).*cosd(lon12)));&#xA;&#xA;        a0=atand(sind(a1).*cosd(lat1)./sqrt((cosd(a1).^2)+(sind(a1).^2).*(sind(lat1).^2)));&#xA;&#xA;        sigma01=atan2d(tand(lat1),cosd(a1));&#xA;        sigma12=atan2d(sqrt((cosd(lat1)*sind(lat2)-sind(lat1)*cosd(lat2)*cosd(lon12))^2+(cosd(lat2)*sind(lon12))^2),(sind(lat1)*sind(lat2)+cosd(lat1)*cosd(lat2)*cosd(lon12)));&#xA;        sigma02=sigma01+sigma12;&#xA;&#xA;        lon01=atan2d(sind(a0)*sind(sigma01),cosd(sigma01));&#xA;        lon0=lon1-lon01;&#xA;&#xA;        sigma=linspace(sigma01,sigma02,N);&#xA;&#xA;        lat=atan2d(cosd(a0)*sind(sigma),sqrt(cosd(sigma).^2+sind(a0)^2*sind(sigma).^2));&#xA;        lon=wrapTo360(atan2d(sind(a0)*sind(sigma),cosd(sigma))+lon0);&#xA;end&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;And for the conversions:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;function  [x,y,utmzone] = deg2utm(Lat,Lon,Huso)&#xA;% -------------------------------------------------------------------------&#xA;% [x,y,utmzone] = deg2utm(Lat,Lon)&#xA;%&#xA;% Description: Function to convert lat/lon vectors into UTM coordinates (WGS84).&#xA;% Some code has been extracted from UTM.m function by Gabriel Ruiz Martinez.&#xA;%&#xA;% Inputs:&#xA;%    Lat: Latitude vector.   Degrees.  +ddd.ddddd  WGS84&#xA;%    Lon: Longitude vector.  Degrees.  +ddd.ddddd  WGS84&#xA;%&#xA;% Outputs:&#xA;%    x, y , utmzone.   See example&#xA;%&#xA;% Example 1:&#xA;%    Lat=[40.3154333; 46.283900; 37.577833; 28.645650; 38.855550; 25.061783];&#xA;%    Lon=[-3.4857166; 7.8012333; -119.95525; -17.759533; -94.7990166; 121.640266];&#xA;%    [x,y,utmzone] = deg2utm(Lat,Lon);&#xA;%    fprintf('%7.0f ',x)&#xA;%       458731  407653  239027  230253  343898  362850&#xA;%    fprintf('%7.0f ',y)&#xA;%      4462881 5126290 4163083 3171843 4302285 2772478&#xA;%    utmzone =&#xA;%       30 T&#xA;%       32 T&#xA;%       11 S&#xA;%       28 R&#xA;%       15 S&#xA;%       51 R&#xA;%&#xA;% Example 2: If you have Lat/Lon coordinates in Degrees, Minutes and Seconds&#xA;%    LatDMS=[40 18 55.56; 46 17 2.04];&#xA;%    LonDMS=[-3 29  8.58;  7 48 4.44];&#xA;%    Lat=dms2deg(mat2dms(LatDMS)); %convert into degrees&#xA;%    Lon=dms2deg(mat2dms(LonDMS)); %convert into degrees&#xA;%    [x,y,utmzone] = deg2utm(Lat,Lon)&#xA;%&#xA;% Author: &#xA;%   Rafael Palacios&#xA;%   Universidad Pontificia Comillas&#xA;%   Madrid, Spain&#xA;% Version: Apr/06, Jun/06, Aug/06, Aug/06&#xA;% Aug/06: fixed a problem (found by Rodolphe Dewarrat) related to southern &#xA;%    hemisphere coordinates. &#xA;% Aug/06: corrected m-Lint warnings&#xA;%-------------------------------------------------------------------------&#xA;&#xA;% Argument checking&#xA;%&#xA;error(nargchk(2, 3, nargin));  %2 arguments required&#xA;CHuso=true;&#xA;if nargin==3&#xA;    CHuso=false;&#xA;end&#xA;n1=length(Lat);&#xA;n2=length(Lon);&#xA;if (n1~=n2)&#xA;   error('Lat and Lon vectors should have the same length');&#xA;end&#xA;&#xA;&#xA;% Memory pre-allocation&#xA;%&#xA;x=zeros(n1,1);&#xA;y=zeros(n1,1);&#xA;utmzone(n1,:)='60 X';&#xA;&#xA;% Main Loop&#xA;%&#xA;for i=1:n1&#xA;   la=Lat(i);&#xA;   lo=Lon(i);&#xA;&#xA;   sa = 6378137.000000 ; sb = 6356752.314245;&#xA;&#xA;   %e = ( ( ( sa ^ 2 ) - ( sb ^ 2 ) ) ^ 0.5 ) / sa;&#xA;   e2 = ( ( ( sa ^ 2 ) - ( sb ^ 2 ) ) ^ 0.5 ) / sb;&#xA;   e2cuadrada = e2 ^ 2;&#xA;   c = ( sa ^ 2 ) / sb;&#xA;   %alpha = ( sa - sb ) / sa;             %f&#xA;   %ablandamiento = 1 / alpha;   % 1/f&#xA;&#xA;   lat = la * ( pi / 180 );&#xA;   lon = lo * ( pi / 180 );&#xA;    if CHuso&#xA;        Huso = fix( ( lo / 6 ) + 31);&#xA;    end&#xA;   S = ( ( Huso * 6 ) - 183 );&#xA;   deltaS = lon - ( S * ( pi / 180 ) );&#xA;&#xA;   if (la&amp;lt;-72), Letra='C';&#xA;   elseif (la&amp;lt;-64), Letra='D';&#xA;   elseif (la&amp;lt;-56), Letra='E';&#xA;   elseif (la&amp;lt;-48), Letra='F';&#xA;   elseif (la&amp;lt;-40), Letra='G';&#xA;   elseif (la&amp;lt;-32), Letra='H';&#xA;   elseif (la&amp;lt;-24), Letra='J';&#xA;   elseif (la&amp;lt;-16), Letra='K';&#xA;   elseif (la&amp;lt;-8), Letra='L';&#xA;   elseif (la&amp;lt;0), Letra='M';&#xA;   elseif (la&amp;lt;8), Letra='N';&#xA;   elseif (la&amp;lt;16), Letra='P';&#xA;   elseif (la&amp;lt;24), Letra='Q';&#xA;   elseif (la&amp;lt;32), Letra='R';&#xA;   elseif (la&amp;lt;40), Letra='S';&#xA;   elseif (la&amp;lt;48), Letra='T';&#xA;   elseif (la&amp;lt;56), Letra='U';&#xA;   elseif (la&amp;lt;64), Letra='V';&#xA;   elseif (la&amp;lt;72), Letra='W';&#xA;   else Letra='X';&#xA;   end&#xA;&#xA;   a = cos(lat) * sin(deltaS);&#xA;   epsilon = 0.5 * log( ( 1 +  a) / ( 1 - a ) );&#xA;   nu = atan( tan(lat) / cos(deltaS) ) - lat;&#xA;   v = ( c / ( ( 1 + ( e2cuadrada * ( cos(lat) ) ^ 2 ) ) ) ^ 0.5 ) * 0.9996;&#xA;   ta = ( e2cuadrada / 2 ) * epsilon ^ 2 * ( cos(lat) ) ^ 2;&#xA;   a1 = sin( 2 * lat );&#xA;   a2 = a1 * ( cos(lat) ) ^ 2;&#xA;   j2 = lat + ( a1 / 2 );&#xA;   j4 = ( ( 3 * j2 ) + a2 ) / 4;&#xA;   j6 = ( ( 5 * j4 ) + ( a2 * ( cos(lat) ) ^ 2) ) / 3;&#xA;   alfa = ( 3 / 4 ) * e2cuadrada;&#xA;   beta = ( 5 / 3 ) * alfa ^ 2;&#xA;   gama = ( 35 / 27 ) * alfa ^ 3;&#xA;   Bm = 0.9996 * c * ( lat - alfa * j2 + beta * j4 - gama * j6 );&#xA;   xx = epsilon * v * ( 1 + ( ta / 3 ) ) + 500000;&#xA;   yy = nu * v * ( 1 + ta ) + Bm;&#xA;&#xA;   if (yy&amp;lt;0)&#xA;       yy=9999999+yy;&#xA;   end&#xA;&#xA;   x(i)=xx;&#xA;   y(i)=yy;&#xA;   utmzone(i,:)=sprintf('%02d %c',Huso,Letra);&#xA;end&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;function  [Lat,Lon] = utm2deg(xx,yy,utmzone)&#xA;% -------------------------------------------------------------------------&#xA;% [Lat,Lon] = utm2deg(x,y,utmzone)&#xA;%&#xA;% Description: Function to convert vectors of UTM coordinates into Lat/Lon vectors (WGS84).&#xA;% Some code has been extracted from UTMIP.m function by Gabriel Ruiz Martinez.&#xA;%&#xA;% Inputs:&#xA;%    x, y , utmzone.&#xA;%&#xA;% Outputs:&#xA;%    Lat: Latitude vector.   Degrees.  +ddd.ddddd  WGS84&#xA;%    Lon: Longitude vector.  Degrees.  +ddd.ddddd  WGS84&#xA;%&#xA;% Example 1:&#xA;% x=[ 458731;  407653;  239027;  230253;  343898;  362850];&#xA;% y=[4462881; 5126290; 4163083; 3171843; 4302285; 2772478];&#xA;% utmzone=['30 T'; '32 T'; '11 S'; '28 R'; '15 S'; '51 R'];&#xA;% [Lat, Lon]=utm2deg(x,y,utmzone);&#xA;% fprintf('%11.6f ',lat)&#xA;%    40.315430   46.283902   37.577834   28.645647   38.855552   25.061780&#xA;% fprintf('%11.6f ',lon)&#xA;%    -3.485713    7.801235 -119.955246  -17.759537  -94.799019  121.640266&#xA;%&#xA;% Example 2: If you need Lat/Lon coordinates in Degrees, Minutes and Seconds&#xA;% [Lat, Lon]=utm2deg(x,y,utmzone);&#xA;% LatDMS=dms2mat(deg2dms(Lat))&#xA;%LatDMS =&#xA;%    40.00         18.00         55.55&#xA;%    46.00         17.00          2.01&#xA;%    37.00         34.00         40.17&#xA;%    28.00         38.00         44.33&#xA;%    38.00         51.00         19.96&#xA;%    25.00          3.00         42.41&#xA;% LonDMS=dms2mat(deg2dms(Lon))&#xA;%LonDMS =&#xA;%    -3.00         29.00          8.61&#xA;%     7.00         48.00          4.40&#xA;%  -119.00         57.00         18.93&#xA;%   -17.00         45.00         34.33&#xA;%   -94.00         47.00         56.47&#xA;%   121.00         38.00         24.96&#xA;%&#xA;% Author: &#xA;%   Rafael Palacios&#xA;%   Universidad Pontificia Comillas&#xA;%   Madrid, Spain&#xA;% Version: Apr/06, Jun/06, Aug/06&#xA;% Aug/06: corrected m-Lint warnings&#xA;%-------------------------------------------------------------------------&#xA;&#xA;% Argument checking&#xA;%&#xA;error(nargchk(3, 3, nargin)); %3 arguments required&#xA;n1=length(xx);&#xA;n2=length(yy);&#xA;n3=size(utmzone,1);&#xA;if (n1~=n2 || n1~=n3)&#xA;   error('x,y and utmzone vectors should have the same number or rows');&#xA;end&#xA;c=size(utmzone,2);&#xA;if (c~=4)&#xA;   error('utmzone should be a vector of strings like &quot;30 T&quot;');&#xA;end&#xA;&#xA;&#xA;&#xA;% Memory pre-allocation&#xA;%&#xA;Lat=zeros(n1,1);&#xA;Lon=zeros(n1,1);&#xA;&#xA;&#xA;% Main Loop&#xA;%&#xA;for i=1:n1&#xA;   if (utmzone(i,4)&amp;gt;'X' || utmzone(i,4)&amp;lt;'C')&#xA;      fprintf('utm2deg: Warning utmzone should be a vector of strings like &quot;30 T&quot;, not &quot;30 t&quot;\n');&#xA;   end&#xA;   if (utmzone(i,4)&amp;gt;'M')&#xA;      hemis='N';   % Northern hemisphere&#xA;   else&#xA;      hemis='S';&#xA;   end&#xA;&#xA;   x=xx(i);&#xA;   y=yy(i);&#xA;   zone=str2double(utmzone(i,1:2));&#xA;&#xA;   sa = 6378137.000000 ; sb = 6356752.314245;&#xA;&#xA;%   e = ( ( ( sa ^ 2 ) - ( sb ^ 2 ) ) ^ 0.5 ) / sa;&#xA;   e2 = ( ( ( sa ^ 2 ) - ( sb ^ 2 ) ) ^ 0.5 ) / sb;&#xA;   e2cuadrada = e2 ^ 2;&#xA;   c = ( sa ^ 2 ) / sb;&#xA;%   alpha = ( sa - sb ) / sa;             %f&#xA;%   ablandamiento = 1 / alpha;   % 1/f&#xA;&#xA;   X = x - 500000;&#xA;&#xA;   if hemis == 'S' || hemis == 's'&#xA;       Y = y - 10000000;&#xA;   else&#xA;       Y = y;&#xA;   end&#xA;&#xA;   S = ( ( zone * 6 ) - 183 ); &#xA;   lat =  Y / ( 6366197.724 * 0.9996 );                                    &#xA;   v = ( c / ( ( 1 + ( e2cuadrada * ( cos(lat) ) ^ 2 ) ) ) ^ 0.5 ) * 0.9996;&#xA;   a = X / v;&#xA;   a1 = sin( 2 * lat );&#xA;   a2 = a1 * ( cos(lat) ) ^ 2;&#xA;   j2 = lat + ( a1 / 2 );&#xA;   j4 = ( ( 3 * j2 ) + a2 ) / 4;&#xA;   j6 = ( ( 5 * j4 ) + ( a2 * ( cos(lat) ) ^ 2) ) / 3;&#xA;   alfa = ( 3 / 4 ) * e2cuadrada;&#xA;   beta = ( 5 / 3 ) * alfa ^ 2;&#xA;   gama = ( 35 / 27 ) * alfa ^ 3;&#xA;   Bm = 0.9996 * c * ( lat - alfa * j2 + beta * j4 - gama * j6 );&#xA;   b = ( Y - Bm ) / v;&#xA;   Epsi = ( ( e2cuadrada * a^ 2 ) / 2 ) * ( cos(lat) )^ 2;&#xA;   Eps = a * ( 1 - ( Epsi / 3 ) );&#xA;   nab = ( b * ( 1 - Epsi ) ) + lat;&#xA;   senoheps = ( exp(Eps) - exp(-Eps) ) / 2;&#xA;   Delt = atan(senoheps / (cos(nab) ) );&#xA;   TaO = atan(cos(Delt) * tan(nab));&#xA;   longitude = (Delt *(180 / pi ) ) + S;&#xA;   latitude = ( lat + ( 1 + e2cuadrada* (cos(lat)^ 2) - ( 3 / 2 ) * e2cuadrada * sin(lat) * cos(lat) * ( TaO - lat ) ) * ( TaO - lat ) ) * ...&#xA;                    (180 / pi);&#xA;&#xA;   Lat(i)=latitude;&#xA;   Lon(i)=longitude;&#xA;&#xA;end&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;I hope that helps.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-04-11T18:07:48.433" LastActivityDate="2019-04-11T18:07:48.433" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16697" PostTypeId="2" ParentId="16694" CreationDate="2019-04-09T22:05:54.877" Score="1" Body="&lt;p&gt;Having the same formula does not mean that the crystal structure is the same. An example is calcium carbonate, which can form the minerals calcite or aragonite. So you have to read the publications to know if they have done X-ray diffraction to positively identify the crystals as petitjeanite. If that is the case, then the crystal structure is triclinic and the relevant data can be found at &lt;a href=&quot;http://webmineral.com/data/Petitjeanite.shtml#.XK0Vh_kzZaQ&quot; rel=&quot;nofollow noreferrer&quot;&gt;webmineral.com&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;ETA: Also note that the unit cell does not necessarily correspond to the visible crystal habit.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2019-04-09T22:05:54.877" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16700" PostTypeId="1" CreationDate="2019-04-10T05:53:45.187" Score="3" ViewCount="48" Body="&lt;p&gt;Tensiometers are instruments used in measuring soil water matric potential (vadose zone water tension) by measuring the vacuum in a water-filled tube that contacts the soil through a porous cup:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7O91b.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7O91b.png&quot; alt=&quot;tensiometer&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Tensiometer_(soil_science)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Electronic tensiometer probe: (1) porous cup; (2) water-filled tube; (3) sensor-head; (4) pressure sensor&lt;/a&gt;&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However there are other sensors that use electrical measurements to determine the matric potential, such as gypsum blocks and porous dielectric water potential sensors. If tensiometer refers to a specific instrument, what is the proper generic term for devices that measure matric potential?&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2019-04-10T05:53:45.187" Title="What is the generic term used for sensors that measure soil water tension?" Tags="|hydrogeology|unsaturated-zone|environmental-sensors|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16701" PostTypeId="2" ParentId="2415" CreationDate="2019-04-10T09:00:45.980" Score="-2" Body="&lt;p&gt;At the time the bend occurred, the earth had a different angle of rotation. Look east of NZ, follow faults in the floor of the pacific and other places, seamount chains etc. Think extinction times, biblical reference to the sun stopping or going backward etc. Whether the result of an asteroid strike, or just a rotational wobble, it explains a lot. The Emporer chain, much of which has now gone under, shows the original line of rotation. The Hawaiian chain the new angle of rotation.&lt;/p&gt;&#xA;" OwnerUserId="15628" LastActivityDate="2019-04-10T09:00:45.980" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16702" PostTypeId="1" CreationDate="2019-04-10T11:17:08.730" Score="1" ViewCount="130" Body="&lt;p&gt;Ther's an graph that appears that the KT asteroid turned the rocks into rubble 3000 km away, else there was a rain of big rocks from the sky. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the rip up clasts and what is the way they were generated? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's at the base of the formation, section 1, lower left. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fObC0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fObC0.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Log from Tanis Site, North Dakota. Document from PNAS &lt;a href=&quot;https://i.stack.imgur.com/VmbIU.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.pnas.org/content/early/2019/03/27/1817407116#xref-ref-33-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Robert A. DePalma, Jan Smit, David A. Burnham, Klaudia Kuiper, Phillip L. Manning, Anton Oleinik, Peter Larson, Florentin J. Maurrasse, Johan Vellekoop, Mark A. Richards, Loren Gurche, Walter Alvarez, (2019)&lt;/strong&gt;: &#xA;&quot;&lt;em&gt;A seismically induced onshore surge deposit at the KPg boundary, North Dakota&lt;/em&gt;&quot;&#xA;&lt;em&gt;Proceedings of the National Academy of Sciences&lt;/em&gt; &lt;strong&gt;Apr 2019&lt;/strong&gt;, 201817407; DOI: 10.1073/pnas.1817407116&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2019-04-21T20:24:23.197" LastActivityDate="2019-04-21T20:24:23.197" Title="What are these basal rip up clasts in North Dakota?" Tags="|earthquakes|sedimentology|stratigraphy|impacts|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16703" PostTypeId="2" ParentId="8746" CreationDate="2019-04-10T16:13:50.543" Score="5" Body="&lt;p&gt;Yes, it's fine, but you should be aware that the earlier period of the data is incapable of showing large variations within a century or so.  They are all smoothed out, even if they happened.  So you get the wrong impression if you assume that temps have been smooth with no centennial scale gyrations.  The plain fact is our data is not good enough to show this level of granularity.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;...no temperature variability is preserved in our reconstruction at cycles shorter than 300 years, 50% is preserved at 1,000-year time scales, and nearly all is preserved at 2,000-year periods and longer.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://dotearth.blogs.nytimes.com/2013/03/31/fresh-thoughts-from-authors-of-a-paper-on-11300-years-of-global-temperature-changes/?_r=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://dotearth.blogs.nytimes.com/2013/03/31/fresh-thoughts-from-authors-of-a-paper-on-11300-years-of-global-temperature-changes/?_r=0&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;My personal Bayesian guess is that the recent temp rise is abnormal in historical perspective.  But you are getting the wrong impression of the surety of that view from looking at the XKCD cartoon.  Randall has a small caveat on this issue but does not go in depth to analyze it (and it is the key issue in extracting insight from the Marcott study).&lt;/p&gt;&#xA;" OwnerUserId="15631" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-04-10T16:43:17.940" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16705" PostTypeId="1" CreationDate="2019-04-11T19:38:58.360" Score="3" ViewCount="23" Body="&lt;p&gt;I have monthly precipitation data and would like to create the frequency curve for the 2, 5, 10, 100 year storms. I have access to NetStorm, STORMS 2000, CFA (from Environment Canada) and HEC-SSP. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The precipitation data is from the Caribbean so I can't use any predefined online databases. This isn't my area of expertise, I've just been given the task&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone tell me how to go about creating these frequency curves for storms?&#xA;Thanks!! &lt;/p&gt;&#xA;" OwnerUserId="15636" LastActivityDate="2019-04-11T19:38:58.360" Title="Rainfall Frequency Analyses" Tags="|atmosphere-modelling|precipitation|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16706" PostTypeId="1" AcceptedAnswerId="24545" CreationDate="2019-04-11T20:03:49.410" Score="3" ViewCount="502" Body="&lt;p&gt;For an effusive volcanic activity, how far an andesitic lava can flow?&#xA;What is the velocity?&lt;/p&gt;&#xA;&lt;p&gt;Eruption volume 0.2 km&lt;sup&gt;3&lt;/sup&gt; with 25 degree slope.&lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="6467" LastEditDate="2022-11-22T22:30:37.117" LastActivityDate="2022-11-22T22:30:37.117" Title="How far can an andesitic lava flow, and what is the velocity?" Tags="|volcanology|fluid-dynamics|volcanic-eruption|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16707" PostTypeId="1" CreationDate="2019-04-12T01:09:14.057" Score="1" ViewCount="97" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xoqxB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xoqxB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In my Geomorphology book there is a section on uplift caused by isostatic rebound and it goes over how the viscoplastic nature of the mantle and the mechanically detached asthenosphere allow a long delayed equilibrium to be reached at the isostatic compensation depth. This is because displaced mantle must flow back into the volume that is now freed up from a crustal load having been removed. Does anyone have any idea where the very bottom equation comes from, in the picture I have provided? I am guessing it may have to due with flow equations that manipulate the Reynolds Number. I think it somehow relates the mean speed to the volume flux but I am having a hard time finding where it comes from. Any insight would be great. &lt;/p&gt;&#xA;" OwnerUserId="14316" LastActivityDate="2019-04-12T01:09:14.057" Title="Equations for Mantle Flow and Isostatic Rebound" Tags="|mantle|isostasy|plastic|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16708" PostTypeId="1" AcceptedAnswerId="16712" CreationDate="2019-04-12T05:35:15.033" Score="4" ViewCount="64" Body="&lt;p&gt;Not an expert in this field but I'm just curious as to how accurate the Google Map is &lt;a href=&quot;https://www.google.com/maps/place/Chile/@64,130.5468889,2.43z/data=!4m5!3m4!1s0x9662c5410425af2f:0x505e1131102b91d!8m2!3d-35.675147!4d-71.542969&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, from the &lt;a href=&quot;https://www.theguardian.com/environment/2016/aug/21/arctic-will-be-ice-free-in-summer-next-year&quot; rel=&quot;nofollow noreferrer&quot;&gt;interview&lt;/a&gt; with scientist Peter Wadhams, his estimate seems to be spot-on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I still remember, as a kid, we used to draw a white landmass when illustrating the Polar North. Now, I think we'll have to teach the kids to draw wavy lines, representing the Arctic Ocean instead!&lt;/p&gt;&#xA;" OwnerUserId="15639" LastActivityDate="2019-04-12T18:56:33.723" Title="Is the Arctic already ice-free during summer?" Tags="|arctic|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16709" PostTypeId="2" ParentId="16685" CreationDate="2019-04-12T08:23:51.043" Score="3" Body="&lt;p&gt;Following @ Friddy's &lt;a href=&quot;https://earthscience.stackexchange.com/users/824/friddy&quot;&gt;comment&lt;/a&gt;, I started reading Aethlabs &lt;a href=&quot;https://aethlabs.com/faq#using-microaeth-ae51&quot; rel=&quot;nofollow noreferrer&quot;&gt;AE51 FAQ&lt;/a&gt; and was quite surprised!&lt;/p&gt;&#xA;&lt;p&gt;While a conventional aethalometer use a long tape and move it to the new position after each measurement (which could be as fast as one measurement per minute), the compact device shown in the image in question uses a single filter position, and just keeps measuring as it gets darker and darker as black carbon collects.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Q:&lt;/strong&gt; Do all the microAeth use the same filters?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;A:&lt;/strong&gt; No. &lt;strong&gt;The microAeth AE51 uses a T60 Teflon-coated borosilicate glass fiber filter strip which has 1 sampling location and must be manually replaced.&lt;/strong&gt; The microAeth MA200 uses a roll of Polytetrafluoroethylene (PTFE) filter material housed in a filter tape cartridge which has 15 sampling locations that can automatically advance. The microAeth MA300 and MA350 use a roll of Polytetrafluoroethylene (PTFE) filter material that is housed in a filter tape cartridge which has 85 sampling locations that can automatically advance. Filter tape cartridges have to be manually replaced much less often than a single use filter strip.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Also:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;[...] A guide for measurement limits regarding saturation can be found on the &lt;a href=&quot;https://aethlabs.com/sites/all/content/microaeth/ae51/microAeth%20AE51%20Specifications%20Sheet%20Rev%2004%20Updated%20Jul%202016.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;AE51 Specifications Sheet&lt;/a&gt;. For example, filters need to be changed according to the following BC concentration/flow rate ranges:&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;pre&gt;&lt;code&gt; - Avg.   5 µg BC/m3   for 24 hours    @ 100 ml/min&#xA; - Avg. 100 µg BC/m3   for  3 hours    @ 50 ml/min&#xA; - Avg.   1 mg BC/m3   for 15 minutes  @ 50 ml/min&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Compare this to a conventional aethalometer:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/khWtw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/khWtw.jpg&quot; alt=&quot;conventional aethalometer&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/File:Aethalometer_interior.JPG&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SBG5j.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SBG5j.jpg&quot; alt=&quot;conventional aethalometer&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://twitter.com/AEMET_Izana/status/821321582643740672&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-04-13T13:13:50.157" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16711" PostTypeId="1" CreationDate="2019-04-12T13:07:50.720" Score="3" ViewCount="41" Body="&lt;p&gt;I've been doing research on vegetation indices to try and prepare for my indoor plant analysis project.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have a question about soil adjustments, specifically soil line based indices like PVI.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the purpose of soil adjustment to offset the indirect effect that the soil has on the pixels of the green material? or to try and negate the soil values when considering the index value of every pixel across an image?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the latter is true, would there be value in using computer vision techniques (such as foreground extraction) to remove the background material altogether?&lt;/p&gt;&#xA;" OwnerUserId="15642" LastEditorUserId="15642" LastEditDate="2019-04-15T00:28:48.853" LastActivityDate="2019-04-15T15:38:00.153" Title="Importance of soil adjusted vegetation indices for indoor use" Tags="|vegetation|ndvi|plant|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16712" PostTypeId="2" ParentId="16708" CreationDate="2019-04-12T18:23:58.783" Score="3" Body="&lt;p&gt;You can follow the sea ice extent here at &lt;a href=&quot;http://polarportal.dk/en/sea-ice-and-icebergs/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://polarportal.dk/en/sea-ice-and-icebergs/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And here at &lt;a href=&quot;http://nsidc.org/arcticseaicenews/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://nsidc.org/arcticseaicenews/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a lot of things you can not see in regular maps as they fill in the area with ice as open sea on their products,It is the same for land areas too they do not change the maps if the ground is covered by snow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the answer to your question,There is still an ice cover in the arctic even if it is starting to get dangerously low at the end of summer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a side note it does look like the arctic ice cover is melting a lot faster this year than what it have done the last ten years on average,You can see a more detailed and year by year graph here &lt;a href=&quot;https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://nsidc.org/arcticseaicenews/charctic-interactive-sea-ice-graph/&lt;/a&gt; for both arctic and antarctic sea ice&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6258" LastEditDate="2019-04-12T18:56:33.723" LastActivityDate="2019-04-12T18:56:33.723" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16713" PostTypeId="2" ParentId="13744" CreationDate="2019-04-12T20:04:31.170" Score="0" Body="&lt;p&gt;I thought they where always present. Methane has a higher effect on Earth? When the carbon dioxide is high enough it will eventually warm the Methane to melt at the poles which then would cause the bulk cloud cover triggering an ice age which then freezes the carbon dioxide and methane again. Methane takes for longer to be absorbed by the ocean and Earth like carbon dioxide. The Earth cannot get to hot or cold because of the balance of the 2 molecules and their role in weather. Plants absorb some carbon dioxide which helps balance this.   &lt;/p&gt;&#xA;" OwnerUserId="5052" LastActivityDate="2019-04-12T20:04:31.170" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16717" PostTypeId="2" ParentId="16598" CreationDate="2019-04-13T02:38:34.203" Score="0" Body="&lt;p&gt;Although erosion rates vary widely depending on the location, tectonic setting, climatic history, fluvial incision, human disturbance, and other factors, there is a paper available online that illustrates and discusses the global variation in erosion rates as measured using cosmogenic nuclides. It is: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Portenga, E.W. and Bierman, P.R., 2011. Understanding Earth’s eroding surface with 10 Be. GSA today, 21(8), pp.4-10.&#xA;&lt;a href=&quot;https://www.geosociety.org/gsatoday/archive/21/8/article/i1052-5173-21-8-4.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.geosociety.org/gsatoday/archive/21/8/article/i1052-5173-21-8-4.htm&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.geosociety.org/gsatoday/archive/21/8/pdf/i1052-5173-21-8-4.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.geosociety.org/gsatoday/archive/21/8/pdf/i1052-5173-21-8-4.pdf&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.geosociety.org/datarepository/2011/2011216.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.geosociety.org/datarepository/2011/2011216.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition, An introduction to erosion rates and the processes that control erosion rates in mountains is the book: Burbank, D.W. and Anderson, R.S., 2009. Tectonic geomorphology. John Wiley &amp;amp; Sons.&lt;/p&gt;&#xA;" OwnerUserId="15648" LastEditorUserId="2470" LastEditDate="2019-04-13T02:44:31.490" LastActivityDate="2019-04-13T02:44:31.490" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16718" PostTypeId="1" CreationDate="2019-04-13T06:44:56.320" Score="1" ViewCount="60" Body="&lt;p&gt;Why not make International Timing Zone just a straight line like this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2QQVC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2QQVC.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8265" LastActivityDate="2019-04-26T02:58:58.263" Title="International Timing Zone" Tags="|mapping|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16720" PostTypeId="2" ParentId="16702" CreationDate="2019-04-13T08:47:57.067" Score="1" Body="&lt;p&gt;&lt;strong&gt;Short answer: They are clasts from adjacent hillside deposited&#xA;inmediately after the &lt;a href=&quot;https://en.wikipedia.org/wiki/Chicxulub_crater&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chicxulub impact&lt;/a&gt;.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;The log you posted represents a sudden onshore inundation event due to the impact.&lt;/p&gt;&#xA;&lt;p&gt;The paper you provided clarifies it&lt;a href=&quot;https://www.pnas.org/content/early/2019/03/27/1817407116#xref-ref-33-1&quot; rel=&quot;nofollow noreferrer&quot;&gt; [1]&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Tanis site, which documents a turbulently deposited, rapidly emplaced&#xA;sediment package directly overlain by the Cretaceous–Paleogene (KPg)&#xA;boundary tonstein. The site, situated in the continental Hell Creek&#xA;Formation in southwestern North Dakota (Fig. 1), displays&#xA;inland-directed flow indicators and holds a mixture of Late Cretaceous&#xA;marine and continental biota, implying that &lt;strong&gt;its emplacement is related&#xA;to sudden onshore inundation surges&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VmbIU.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VmbIU.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Figure 1&lt;/strong&gt;: Tanis Site, North Dakota.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PW8lP.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PW8lP.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Figure 2&lt;/strong&gt;: Log of Tanis Site, North Dakota.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The unit 1 is described bellow. The contact between conglomerates and the point-bar is non gradational, and the rip-up clasts come from Hell Creek strata above the river (1C).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The base of unit 1 comprises a matrix-supported, massive coarse-sand&#xA;conglomerate, with angular pebble- &lt;strong&gt;to small boulder-sized rip-up&#xA;clasts derived from the underlying Hell Creek strata&lt;/strong&gt;. As shown in Fig.&#xA;2, the massive sand (1a) at the base of &lt;strong&gt;unit 1 has a sharp&#xA;non gradational basal contact with the underlying point-bar&lt;/strong&gt; surface and&#xA;vertically grades into a thin (∼3-cm) zone of plane-parallel bedding&#xA;of interlaminated sand–silt (lower 1b); climbing ripples (mid 1b);&#xA;sinuous, wavy lamination (upper 1b); low-angle cross-lamination (lower&#xA;1c); fine, discontinuous subparallel lamination (upper 1c); and nearly&#xA;structureless fine silt/mud near the top (1d). &lt;strong&gt;Flow-direction reverses&#xA;180° toward the east—seaward—near the top of unit 1&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;My guess is they were transported to the sand-bar from the hillside because of the sudden event, before the conglomerate clasts started to fall from the sky.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;The whole depositional unit took place shortly, and before the iridium layer.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Because the Tanis deposit contains ejecta throughout and is also&#xA;capped by the KPg tonstein, &lt;strong&gt;the depositional event took place&#xA;during a narrow window of time: after impact but before deposition&#xA;of the fine-grained KPg tonstein&lt;/strong&gt;. Given this constraint, we can&#xA;deduce that the Event Deposit was emplaced within a matter of hours&#xA;after the Chicxulub impact event.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The subsequent conglomerates are aerial deposits .The event is nicely described at the paper.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;We assume a scenario in which ejecta-curtain material, launched at&#xA;about a 45° elevation angle and seen as the glassy or altered-glass&#xA;spherules at Tanis, arrived before the shocked quartz that was&#xA;launched at steep angles in a “warm fireball” produced by release of&#xA;CO2 from shocked limestone after departure of the ejecta curtain&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.pnas.org/content/early/2019/03/27/1817407116#xref-ref-33-1&quot; rel=&quot;nofollow noreferrer&quot;&gt; 1    &lt;strong&gt;Robert A. DePalma, Jan Smit, David A. Burnham, Klaudia Kuiper, Phillip L. Manning, Anton Oleinik, Peter Larson, Florentin J. Maurrasse, Johan Vellekoop, Mark A. Richards, Loren Gurche, Walter Alvarez, (2019)&lt;/strong&gt;:&#xA;&amp;quot;&lt;em&gt;A seismically induced onshore surge deposit at the KPg boundary, North Dakota&lt;/em&gt;&amp;quot;&#xA;&lt;em&gt;Proceedings of the National Academy of Sciences&lt;/em&gt; &lt;strong&gt;Apr 2019&lt;/strong&gt;, 201817407; DOI: 10.1073/pnas.1817407116&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorUserId="-1" LastEditorDisplayName="user12525" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-04-13T11:21:37.840" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16721" PostTypeId="2" ParentId="16718" CreationDate="2019-04-13T09:31:34.480" Score="2" Body="&lt;p&gt;In a perfect world the &lt;a href=&quot;https://en.wikipedia.org/wiki/International_Date_Line&quot; rel=&quot;nofollow noreferrer&quot;&gt;international date line&lt;/a&gt; would run directly along the 180 degree line of latitude. The reason it doesn't is due to the borders of Pacific island nations. No nation wants to  have the eastern part of its country have a different day to the western part of its country just because of an arbitrarily drawn line on a map.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-04-13T09:31:34.480" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16722" PostTypeId="2" ParentId="16706" CreationDate="2019-04-13T09:35:44.490" Score="5" Body="&lt;p&gt;&lt;a href=&quot;https://volcanoes.usgs.gov/vhp/lava_flows.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Andesitic lava&lt;/a&gt; is viscous, compared to basaltic lava. Andesitic lava flows at a rate of a few kilometers per hour, whereas basaltic lava can flow up to 10 km/h. Because of their viscosity, andesitic lavas &quot;rarely extend beyound 8 km from their vents&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://link.springer.com/article/10.5047/eps.2013.05.018&quot; rel=&quot;nofollow noreferrer&quot;&gt;Viscosity of andesite lava and its implications for possible drain-back processes in the 2011 eruption of the Shinmoedake volcano, Japan&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2012GC004336&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pulsatory andesite lava flow at Bagana Volcano&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.tulane.edu/~sanelson/Natural_Disasters/volcan&amp;amp;magma.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Volcanoes, Magma, and Volcanic Eruptions - Tulane University&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2019-04-14T03:24:08.560" LastActivityDate="2019-04-14T03:24:08.560" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16725" PostTypeId="2" ParentId="16688" CreationDate="2019-04-13T12:34:42.647" Score="15" Body="&lt;p&gt;&lt;strong&gt;tl;dr:&lt;/strong&gt; The Earth receives 40,000 tons of dust from space every year, but looses 95,000 tons of Hydrogen and 1,600 tons of Helium every year as well. After all additional effects are balanced, &lt;strong&gt;the Earth looses about 50,000 tons a year&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;It seems a similar question was asked in Astronomy Stack Exchange, and &lt;a href=&quot;https://astronomy.stackexchange.com/a/11830/7982&quot;&gt;this short answer&lt;/a&gt; links to the BBC News article &lt;a href=&quot;https://www.bbc.com/news/magazine-16787636&quot; rel=&quot;noreferrer&quot;&gt;Who, What, Why: Is the Earth getting lighter?&lt;/a&gt; which answers this question.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;There are factors that are causing Earth to both gain and lose mass over time, according to Dr Chris Smith, a medical microbiologist and broadcaster who tries to improve the public understanding of science.&lt;/p&gt;&#xA;&lt;p&gt;Using some back-of-the-envelope-style calculations, Dr Smith, with help from physicist and Cambridge University colleague Dave Ansell, drew up a balance sheet of what's coming in, and what's going out. All figures are estimated.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;By far the biggest contributor to the world's mass is the 40,000 tonnes of dust that is falling from space to Earth&lt;/strong&gt;, says Dr Smith.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Surprisingly, General Relativistic effects of Global Warming is considered!&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Nasa has calculated that the Earth is gaining energy due to rising temperatures. Dr Smith and his colleague Mr Ansell estimate this added energy increases the mass of Earth by a tiny amount - &lt;strong&gt;160 tonnes&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Using &lt;span class=&quot;math-container&quot;&gt;$E=mc^2$&lt;/span&gt; that works out to about &lt;span class=&quot;math-container&quot;&gt;$1.4 \times 10^{22}$&lt;/span&gt; Joules/year or &lt;span class=&quot;math-container&quot;&gt;$4.6 \times 10^{14}$&lt;/span&gt; Watts. That's about 3.6 Watts/meter^2 or about 0.3% of the total power coming from the Sun, so it does seem to be back-of-the-envelope-in-the ballpark correct!&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;But there is something else that is making the planet lose mass. Gases such as hydrogen are so light, they are escaping from the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Physicists have shown that the Earth is losing about three kilograms of hydrogen gas every second. &lt;strong&gt;It's about 95,000 tonnes of hydrogen that the planet is losing every year&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;The other very light gas this is happening to is helium and there is much less of that around, so &lt;strong&gt;it's about 1,600 tonnes a year of helium that we lose&lt;/strong&gt;.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;So taking into account the gains and the losses, Dr Smith reckons &lt;strong&gt;the Earth is getting about 50,000 tonnes lighter a year&lt;/strong&gt;, which is just less than half the gross weight of the Costa Concordia, the Italian cruise liner, that ran aground recently.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-04-13T12:34:42.647" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16726" PostTypeId="1" CreationDate="2019-04-13T13:35:10.207" Score="8" ViewCount="496" Body="&lt;p&gt;&lt;a href=&quot;https://twitter.com/AEMET_Izana/status/1109424115193204736&quot; rel=&quot;noreferrer&quot;&gt;This tweet&lt;/a&gt; from the account of the Centro de Investigación Atmosférica de Izaña (AEMET) &lt;a href=&quot;http://izana.aemet.es&quot; rel=&quot;noreferrer&quot;&gt;http://izana.aemet.es&lt;/a&gt;  &lt;em&gt;Izaña Atmospheric Research Center (AEMET)&lt;/em&gt; shows images of meteorological instruments pointing at the Sun. I recognize the small glass domed instruments in several images and in detail in the first image as &lt;a href=&quot;https://en.wikipedia.org/wiki/Pyranometer&quot; rel=&quot;noreferrer&quot;&gt;Pyranometers&lt;/a&gt; based on &lt;a href=&quot;https://earthscience.stackexchange.com/a/16479/6031&quot;&gt;this excellent and thorough answer&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But what are the long, thin telescope-like cylindrical objects, each on its own articulated pointer to track the Sun? There seems to be a whole series of them in the background in the fourth image.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KjLwY.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KjLwY.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/S4REg.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/S4REg.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GCXU9.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GCXU9.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/nl6Iz.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nl6Iz.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorDisplayName="user12525" LastEditDate="2019-08-27T10:55:44.257" LastActivityDate="2019-08-27T10:55:44.257" Title="What are these Gizmos at Izaña Atmospheric Research Center in Spain?" Tags="|meteorology|earth-observation|instrumentation|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16727" PostTypeId="2" ParentId="16726" CreationDate="2019-04-13T15:41:57.193" Score="9" Body="&lt;p&gt;Those are Sun/Moon multispectral photometers and ski radiometers. These are instruments that can scan the sky or track the Sun/Moon for direct measurements. They measure light intensity at multiple narrow wavelength bands, and are designed to measure atmospheric aerosols content and characteristics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ones in the third image seem to be a &lt;a href=&quot;https://www.cimel.fr/?instrument=sun-sky-lunar-multiband-photometer&amp;amp;lang=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;CIMEL CE-138 Sun Sky Lunar Multispectral Photometer&lt;/a&gt; (&lt;a href=&quot;http://cimel-wiki.recherche.usherbrooke.ca/cimel/index.php?title=CIMEL_318_-_general_specifications&quot; rel=&quot;nofollow noreferrer&quot;&gt;specs&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mBxZ4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mBxZ4.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is just a few brands that make these instruments. Others are &lt;a href=&quot;http://www.isac.cnr.it/en/infrastructures/prede-pom-01-radiometer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Prede&lt;/a&gt; and &lt;a href=&quot;https://www.kippzonen.es/Download/414/POM-01-POM-02-Sky-Radiometer-and-PGS-100-Sun-Photometer-Brochure&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kipp &amp;amp; Zonen&lt;/a&gt;. I don't know why they have so many at the AEMET. Perhaps it is some sort of instrumentation investigation, where they are testing different types of photometers or different wavelengths. Or perhaps, as these instruments have a filter wheel inside, each one may have a different set of filters to have higher multispectral resolution.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-04-14T15:11:26.207" LastActivityDate="2019-04-14T15:11:26.207" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16728" PostTypeId="2" ParentId="16694" CreationDate="2019-04-13T16:13:21.040" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Should one assume that the mineral petitjeanite and the chemical discussed in the recent Chemical &amp;amp; Engineering News article Photocatalyst shreds drinking water contaminant PFOA are probably the same crystal configuration and unit cell, or can there be some variety?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No you cannot assume the structure from the formula, many materials have polymorphs (think graphite vs. diamond). To know if the structures are the same you must look at the diffraction pattern from &lt;a href=&quot;https://pubs.acs.org/doi/10.1021/acs.estlett.8b00395&quot; rel=&quot;nofollow noreferrer&quot;&gt;the paper&lt;/a&gt;. In the paper the synthesized bismuth oxyhydroxyphosphate matches that of petitjeanite so in this case that is the prototype structure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://pubs.acs.org/doi/10.1021/acs.estlett.8b00395&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UqJAF.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using the information about diffraction, from the ICDD Databse (pdf 01-082-8058)we find that petitjeanite is a triclinic system of the &lt;span class=&quot;math-container&quot;&gt;$\mathrm P\bar 1$&lt;/span&gt; space group (#2). with lattice parameters of: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\require{mediawiki-texvc}$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$a = 9.798\AA; ~ b =  7.250\AA; ~ c= 6.866 \AA; \qquad \alpha = 88.280^\circ \beta = 115.270^\circ ~ \gamma = 110.700^\circ$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and atomic positions of:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\begin{array}{c|lll}&#xA;\text{Atom}&amp;amp;x&amp;amp;y&amp;amp;z\\&#xA;\hline&#xA;\ce{Bi}&amp;amp;~~~0.52327&amp;amp;~~~0.41421&amp;amp;~~~0.7523\\&#xA;\ce{Bi}&amp;amp;~~~0.29838&amp;amp;~~~0.74044&amp;amp;~~~0.55549\\&#xA;\ce{Bi}&amp;amp;~~~0.07735&amp;amp;~~~0.1609&amp;amp;~~~0.28045\\&#xA;\ce{P}&amp;amp;~~~0.6952&amp;amp;~~~0.0172&amp;amp;~~~0.9215\\&#xA;\ce{P}&amp;amp;~~~0.0961&amp;amp;~~~0.372&amp;amp;~~~0.7862\\&#xA;\ce{O}&amp;amp;~~~0.3777&amp;amp;~~~0.5382&amp;amp;~~~0.4759\\&#xA;\ce{O}&amp;amp;~~~0.3066&amp;amp;~~~0.1549&amp;amp;~~~0.5579\\&#xA;\ce{O}&amp;amp;~~~0.859&amp;amp;~~~0.0275&amp;amp;~~~0.8943\\&#xA;\ce{O}&amp;amp;~~~0.5569&amp;amp;-0.2084&amp;amp;~~~0.8602\\&#xA;\ce{O}&amp;amp;~~~0.621&amp;amp;~~~0.1596&amp;amp;~~~0.7526\\&#xA;\ce{O}&amp;amp;~~~0.7684&amp;amp;~~~0.1052&amp;amp;~~~1.1811\\&#xA;\ce{O}&amp;amp;~~~0.2584&amp;amp;~~~0.5101&amp;amp;~~~0.7497\\&#xA;\ce{O}&amp;amp;-0.0468&amp;amp;~~~0.4637&amp;amp;~~~0.6902\\&#xA;\ce{O}&amp;amp;~~~0.0209&amp;amp;~~~0.1498&amp;amp;~~~0.6362\\&#xA;\ce{O}&amp;amp;~~~0.1695&amp;amp;~~~0.3727&amp;amp;~~~1.0506\\&#xA;\end{array}&#xA;$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and last but not least this renders to an image of:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fwn9n.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fwn9n.png&quot; alt=&quot;unit cell&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Purple: Bi&lt;br&gt;&#xA;Orange: P&lt;br&gt;&#xA;Red: O&lt;/p&gt;&#xA;" OwnerUserId="15655" LastActivityDate="2019-04-13T16:13:21.040" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16730" PostTypeId="1" CreationDate="2019-04-13T17:03:21.153" Score="2" ViewCount="251" Body="&lt;p&gt;Nature communications article &quot;&lt;a href=&quot;https://www.nature.com/articles/423239a&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mission to Earth's core — a modest proposal&lt;/a&gt;&quot;, suggests placing a large volume of liquid iron in a crack and let it sink all the way to the Earth's core, carrying along a probe that can transmit data using seismic waves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is an interesting idea. Although there might be many technical problems I feel no one seems insurmountable and it is worth a try.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I wonder why the author suggest using a liquid iron instead of a liquid lead. I would expect lead to be cheaper and also require a smaller volume to achieve the same fracture stresses (due to higher density).&#xA;In addition, a lower melting point would facilitate the initiation of the fracture propagation near the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Would lead dissolve in the surrounding magma? Would it chemically interact turning into a lighter compound?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the original article is behind a paywall I copy here the main text:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/odBdh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/odBdh.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Kv9vM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Kv9vM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="11908" LastEditDate="2019-04-13T17:15:09.080" LastActivityDate="2019-04-14T01:29:22.387" Title="Why the &quot;Mission to Earth’s core&quot; proposal suggests using liquid iron instead of lead?" Tags="|geophysics|geochemistry|core|mantle|magmatism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16731" PostTypeId="2" ParentId="9477" CreationDate="2019-04-13T18:34:53.380" Score="2" Body="&lt;p&gt;There are three possible sources for the reported limestone nodules from the clay horizon from colluvium and alluvium. First, as noted before, they could be either detrital gravel of limestone either eroded from limestone bedrock. Given that the bedrock source from which this gravel was eroded and transported from could be either local or regional, such gravels tells a person nothing about the composition of the bedrock at your site. Second, the &quot;limestone nodules&quot; might also be limestone gravel that was either brought in either as construction material or eroded and redeposited from larger limestone blocks at some ancient ruin. Again, such gravel could come from any source within either the local area or region. This means that the presence of such material tells a person nothing about of what the local bedrock consists.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, it is interesting that the &quot;limestone nodules&quot; occur in a clay layer. Normally, gravel-size pieces of limestone are not deposited together with clay. This and the clay layer being part of a soil suggest that the limestone nodules&quot; are caliche nodules / concretions that precipitated and formed in place within the soil as part of a Petrocalcic “K” horizon of a soil developed in clayey colluvium and alluvium. Since caliche (calcrete) forms in Quaternary colluvium and alluvium independently of the type of local bedrock, the presence of caliche tells a person nothing about the local bedrock might be. The Soil Map of Tunisia at &lt;a href=&quot;https://library.wur.nl/isric/kaart/origineel/afr_tnped.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://library.wur.nl/isric/kaart/origineel/afr_tnped.jpg&lt;/a&gt; might tell a person whether such soils are present within the area. The presence of &quot;limestone nodules&quot; does not indicate what the local bedrock might be composed of as there are multiple possible origins for them that are independent of the underlying bedrock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A possibly useful map is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ben Haj Ali, M., Jedoui, Y., Dali, T., Ben Salem, H. &amp;amp; Memmi, L. (1985): Carte géologique de la Tunisie, echelle 1:500,000.– Office Topographie Cartographie; Tunis&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Petrocalcic Horizon - &lt;a href=&quot;https://en.wikipedia.org/wiki/Petrocalcic_Horizon&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Petrocalcic_Horizon&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;caliche / calcrete - &lt;a href=&quot;https://en.wikipedia.org/wiki/Caliche&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Caliche&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15648" LastActivityDate="2019-04-13T18:34:53.380" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16732" PostTypeId="2" ParentId="16726" CreationDate="2019-04-14T00:33:42.747" Score="5" Body="&lt;p&gt;I am going to just give a slightly different perspective to the answer above by actually naming the instrument in OP's question. Based on the name BSRN in OP's second image that actually translates to this institution - &lt;a href=&quot;https://bsrn.awi.de/project/background/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Baseline Surface Radiation Network&lt;/a&gt; the cylindrical instrument in the photograph shown is actually a &lt;a href=&quot;https://en.wikipedia.org/wiki/Pyrheliometer&quot; rel=&quot;nofollow noreferrer&quot;&gt;pyrheliometer&lt;/a&gt;. In an &lt;a href=&quot;https://earthscience.stackexchange.com/questions/16478/what-are-these-gizmos-at-mauna-loa-observatory/16479#16479&quot;&gt;earlier answer&lt;/a&gt; I talked about &lt;a href=&quot;https://en.wikipedia.org/wiki/Pyranometer&quot; rel=&quot;nofollow noreferrer&quot;&gt;pyranometers&lt;/a&gt;. So what is the difference between a pyrheliometer and a pyranometer ? So a pyranometer measures both the direct solar beam as well as the diffuse radiation that is falling on a surface whereas the pyrheliometer measures only the direct sky beam. So the pyrheliometer in this case can be combined with a spectral radiometer manufactured by &lt;a href=&quot;https://eko-eu.com/applications/dni-measurements-at-cpv-sites&quot; rel=&quot;nofollow noreferrer&quot;&gt;EKO&lt;/a&gt; to measure direct normal irradiance. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the &lt;a href=&quot;https://bsrn.awi.de/other/frequently-asked-questions/news/2015-2016/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Frequently Asked Questions&lt;/a&gt; of the BSRN site this particular difference is covered &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The measurements called &quot;Direct radiation&quot; are obtained from normal incidence pyrheliometers which get pointed by solar trackers into the direct sun beam. The measurements called &quot;Diffuse radiation&quot; and &quot;Short-wave downward (GLOBAL) radiation&quot; are taken from pyranometers oriented horizontally with respect to the Earth´s surface. The three measurements are taken independently from each other. Thus, &quot;Direct&quot; + &quot;Diffuse&quot; differs &quot;Global&quot; slightly even if only the horizontal component from &quot;Direct&quot; was used. These differences can be used to quantify the quality of the data &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not all the glass domed instruments shown in OP's image are necessarily pyranometers. Some of them can be &lt;a href=&quot;https://en.wikipedia.org/wiki/Pyrgeometer&quot; rel=&quot;nofollow noreferrer&quot;&gt;pyrgeometers&lt;/a&gt; that measures near surface long wave radiation. The &lt;a href=&quot;https://www.kippzonen.com/ProductGroup/4/Pyrgeometers&quot; rel=&quot;nofollow noreferrer&quot;&gt;company that manufactures them&lt;/a&gt; as mentioned in Camilo's answer i.e.  specifically mention that BSRN facility uses them in this &lt;a href=&quot;https://www.google.com/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=1&amp;amp;cad=rja&amp;amp;uact=8&amp;amp;ved=2ahUKEwizqcmbr87hAhXUZSsKHQzXBS0QFjAAegQIBRAC&amp;amp;url=https%3A%2F%2Fwww.kippzonen.com%2FDownload%2F124%2FScientific-Solar-Monitoring-Station-BSRN-requirements&amp;amp;usg=AOvVaw3qfcgORBJ5UplkdBGc6hl_&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kipp and Zonen Overview of BSRN requirements&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is noted from this link  &lt;a href=&quot;https://www.pangaea.de/ddi?request=bsrn/BSRNEvent&amp;amp;format=html&amp;amp;title=BSRN%20Stations&quot; rel=&quot;nofollow noreferrer&quot;&gt;BSRN stations&lt;/a&gt; that &lt;a href=&quot;http://izana.aemet.es&quot; rel=&quot;nofollow noreferrer&quot;&gt; Izaña Atmospheric Research Center&lt;/a&gt; is one of the BSRN stations that is monitoring surface radiation and a link to that station is provided here &lt;a href=&quot;http://www.bsrn.aemet.es/&quot; rel=&quot;nofollow noreferrer&quot;&gt;BSRN Izana Data&lt;/a&gt; and a list of their instruments here &lt;a href=&quot;http://www.bsrn.aemet.es/index.php?option=com_content&amp;amp;view=section&amp;amp;id=7&amp;amp;Itemid=58&quot; rel=&quot;nofollow noreferrer&quot;&gt;List of instruments at BSRN Izana&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is BSRN Izana an ideal location for studying radiation ? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From this link - &lt;a href=&quot;http://www.bsrn.aemet.es/index.php?option=com_content&amp;amp;view=section&amp;amp;id=6&amp;amp;Itemid=57&quot; rel=&quot;nofollow noreferrer&quot;&gt;Izana Climate&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Located North of the Tropic of Cancer, the Canary Islands are affected practically all year by the high pressure belt from middle latitudes, specifically by the southern side of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Azores_High&quot; rel=&quot;nofollow noreferrer&quot;&gt;Azores Anticyclone&lt;/a&gt;. The station is located at 2400 meters above sea level, in the free troposphere above the quasi-permanent inversion layer present in the Canary Islands.The climate in the area of the station is extremely dry for the majority of the year, this together with the clean air from the upper troposphere gives the area a major scientific interest. In these days when the climate is dry, the insolation is very high, especially during the summer with consequent daytime warming, while during winter nights there is a substantial thermal cooling.The largest contribution to rainfall in the area occurs during a few days of winter produced by Atlantic Storms affecting the Canary Islands.The precipitation is concentrated in six months from October to March, with an absolute maximum between December and January and another relative in March, while from April until September the contribution is virtually null&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason why they have so many instruments  is because Izana Observatory belong to different  aerosol and radiation networks and few of them are listed here &lt;a href=&quot;http://izana.aemet.es/index.php?option=com_content&amp;amp;view=article&amp;amp;id=43&amp;amp;Itemid=44&amp;amp;lang=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;AERONET Sun Photometers&lt;/a&gt;, &lt;a href=&quot;https://www.pmodwrc.ch/weltstrahlungszentrum/worcc/&quot; rel=&quot;nofollow noreferrer&quot;&gt;GAW-PFR&lt;/a&gt;, &lt;a href=&quot;https://bsrn.awi.de/&quot; rel=&quot;nofollow noreferrer&quot;&gt;BSRN&lt;/a&gt;, &lt;a href=&quot;http://radiationnetwork.com/WorldMaps.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Radiation Network&lt;/a&gt; and also for &lt;a href=&quot;http://www.wmo.int/pages/prog/www/IMOP/TB_LC/Testbed_Izana.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;WMO CIMO Testbed for Aerosols and Water Vapor Remote Sensing instruments&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-04-16T06:28:22.600" LastActivityDate="2019-04-16T06:28:22.600" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16733" PostTypeId="2" ParentId="16730" CreationDate="2019-04-14T01:29:22.387" Score="3" Body="&lt;p&gt;I've already commented on this before &lt;a href=&quot;https://earthscience.stackexchange.com/a/454/725&quot;&gt;here&lt;/a&gt;. This will not work regardless of whether this is iron or lead or anything else. The fact that it was published in Nature does not mean it is true, always remember that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A 10&lt;sup&gt;8&lt;/sup&gt; kg ball of iron would have about &lt;a href=&quot;https://www.wolframalpha.com/input/?i=1E8%20kg%20of%20iron&quot; rel=&quot;nofollow noreferrer&quot;&gt;30 metres in diameter&lt;/a&gt;, which is not a lot, compared to Earth scales.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is why it will not work:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;We have very massive objects on the surface. They are called buildings. They don't sink. Even though they are not that dense, buildings stand on foundations that funnel their mass to a small area, creating very large pressures. The point of the foundations is to hold the building on solid rock so they &lt;em&gt;do not&lt;/em&gt; sink.&lt;/li&gt;&#xA;&lt;li&gt;The author suggests to initiate the crack with explosives. Perhaps a nuclear explosion. We had many nuclear explosions in the past - they don't make cracks. They make craters.&lt;/li&gt;&#xA;&lt;li&gt;Crack propagation is only relevant in the lithosphere. Once you get to the asthenosphere, about 200 kilometres deep, cracks don't propagate any more and the equations the author presents are meaningless. Plastic behaviour of rocks is achieved much earlier anyway.&lt;/li&gt;&#xA;&lt;li&gt;Even if there is a crack, it will have smaller cracks radiating from it. The liquid iron, being liquid, will fill those smaller cracks and lose from the mass of the main liquid blob. With time, the blob will get smaller and smaller until it will not be able to do anything any more.&lt;/li&gt;&#xA;&lt;li&gt;The melting point of iron is more than 1500 °C, this higher than the temperature of the ambient rocks. It will lose heat quicker than it gains by gravitational potential and solidify.&lt;/li&gt;&#xA;&lt;li&gt;The iron will react with the rocks around it. Particularly if it is liquid, because these things are highly reactive. It will start dissolving things into it (which will counter point 5), but it will also lose iron to the surrounding rocks. It will dissolve oxygen, carbon, sulfur, possibly alkalis like sodium, maybe silicon. These are light elements that will overall lower the density of the ball of iron, bringing it to a stop.&lt;/li&gt;&#xA;&lt;li&gt;The oxygen fugacity of the crust and upper mantle is higher than iron-wustite, which will be imposed by the equilibrium with iron. Therefore, it will leach oxygen from the surrounding rocks, essentially turning some of the liquid iron into &quot;rock&quot;. This will also decrease the mass of the blob of iron.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;You were specifically asking about lead. All points above (except 5) are equally applicable to lead.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-04-14T01:29:22.387" CommentCount="15" ContentLicense="CC BY-SA 4.0" />
  <row Id="16734" PostTypeId="1" CreationDate="2019-04-14T03:07:28.023" Score="2" ViewCount="186" Body="&lt;p&gt;if the temperature of a felsic magma is about 800-650 °C and olivine melting point oscillates between end members forsterite and fayalite near 1900-1200 °C, Does this mean that an olivine crystal in the magma would never melt, even if it were very small in relation to the amount of magma?&lt;/p&gt;&#xA;" OwnerUserId="15657" LastActivityDate="2019-04-14T03:56:30.703" Title="could a rhyolitic magma melt a ferromagnesian mineral like olivine?" Tags="|geology|petrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16735" PostTypeId="2" ParentId="16734" CreationDate="2019-04-14T03:56:30.703" Score="1" Body="&lt;p&gt;This is an excellent question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What does happen when you drop a crystal of olivine into liquid rhyolite?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are several answers which all depend on the exact composition of the olivine, how much magnesium is in the rhyolite, temperature, size of the olivine, how much olivine are you dropping into how much rhyolite, and more.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's take the most extreme case of dropping pure Mg olivine (forsterite) into pure felsic rhyolite (a feldspar–quartz liquid mixture). For argument's sake let's assume full thermodynamic equilibrium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, rhyolites can dissolve some amount of Mg. Not much. Maybe 1%, maybe 2%. If it's only a tiny bit of olivine, the olivine will dissolve as a liquid into the rhyolite (you might call it &quot;melt&quot;, but that's not the correct term), making the rhyolite a bit more magnesian.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you add a bit more olivine, you saturate the melt with Mg. This means that a certain magnesian mineral will form in equilibrium with the rhyolite liquid. This could be biotite, amphibole, a clinopyroxene, etc. But because our simple system has no water and no calcium, pure solid olivine sounds like a good choice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, forsterite is not stable in felsic systems. It will react according to the reaction:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\ce{Mg2SiO4 + SiO2 = 2MgSiO3}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the reaction of forsterite (Mg-olivine), reacting with quartz, to form enstatite (orthopyroxene). Therefore, your olivine doesn't melt. It converts to a different mineral: orthopyroxene!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is well illustrated by the following phase diagram, coming from &lt;a href=&quot;https://www.tulane.edu/~sanelson/eens211/2compphasdiag.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this website&lt;/a&gt;:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/8R1nQ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8R1nQ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some more related questions and answers:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/14205/725&quot;&gt;Melting point of minerals&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/174/725&quot;&gt;Why do felsic materials have lower melting points than mafic?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-04-14T03:56:30.703" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16737" PostTypeId="1" CreationDate="2019-04-14T19:19:04.663" Score="1" ViewCount="236" Body="&lt;p&gt;What are the hottest average annual temperature for life in the ocean to withstand? Particularly algae&#xA;This could include life from all points in earth history.&lt;/p&gt;&#xA;" OwnerUserId="15660" LastActivityDate="2019-04-15T03:47:55.583" Title="What are the hottest temperatures ocean life can survive at" Tags="|oceanography|temperature|climatology|hypothetical|evolution|" AnswerCount="1" CommentCount="8" ClosedDate="2019-04-15T14:05:48.170" ContentLicense="CC BY-SA 4.0" />
  <row Id="16738" PostTypeId="2" ParentId="16653" CreationDate="2019-04-14T20:13:36.340" Score="3" Body="&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Is &amp;quot;Chasm One&amp;quot; an &amp;quot;official&amp;quot; name for the feature?&lt;/p&gt;&#xA;&lt;p&gt;No. This is only an informal name used to designate a rift structure (fracture) in the Brunt Ice Shelf, East Antarctica. For example, another rift structure, which trends perpendicular to &amp;quot;Chasm 1,&amp;quot; was informally named the &amp;quot;Halloween Crack&amp;quot; because it was first detected on October 31, 2016.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;How was the term coined?&lt;/p&gt;&#xA;&lt;p&gt;It is one of two rift structures that are arbitrarily and sequentially numbered, &amp;quot;Chasm 1&amp;quot; and &amp;quot;Chasm 2&amp;quot;, starting from the seaward edge of the Brunt Ice Shelf, East Antarctica inland along the ice shelf as shown in Figures 1 and 2 0f King et a. (2017).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Will there be a new Chasm One someday, or will the name be retired after this one splits?&lt;/p&gt;&#xA;&lt;p&gt;The name will likely be retired because having multiple &amp;quot;Chasm 1&amp;quot;s in the same ice shelf will be too confusing. Most likely as new rift structures from the sequential naming of them, e.g. &amp;quot;Chasm 3,&amp;quot; &amp;quot;Chasm 4,&amp;quot; and so forth would continue.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;The papers are:&lt;/p&gt;&#xA;&lt;p&gt;de Rydt, Jan, Gudmundsson, Hilmar, Nagler, Thomas, Wuite, Jan and King, Edward (2018) Recent rift formation and impact on the structural integrity of the Brunt Ice Shelf, East Antarctica. The Cryosphere, 12 (2). pp. 505-520. ISSN 1994-0424 &lt;a href=&quot;http://dx.doi.org/10.5194/tc-12-505-2018&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://dx.doi.org/10.5194/tc-12-505-2018&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;de Rydt, J., Gudmundsson, G. H., Nagler, T., and Wuite, J.: Calving cycle of the Brunt Ice Shelf, Antarctica, driven by changes in ice-shelf geometry, The Cryosphere Discuss., &lt;a href=&quot;https://doi.org/10.5194/tc-2019-46&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.5194/tc-2019-46&lt;/a&gt;, in review, 2019 &lt;a href=&quot;https://www.the-cryosphere-discuss.net/tc-2019-46/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.the-cryosphere-discuss.net/tc-2019-46/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;King, E. C., De Rydt, J., and Gudmundsson, G. H.: The internal structure of the Brunt Ice Shelf from ice-penetrating radar analysis and implications for ice shelf fracture, The Cryosphere, 12, 3361-3372, &lt;a href=&quot;https://doi.org/10.5194/tc-12-3361-2018&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.5194/tc-12-3361-2018&lt;/a&gt;, 2018. &lt;a href=&quot;https://www.the-cryosphere.net/12/3361/2018/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.the-cryosphere.net/12/3361/2018/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Hodgson, Dominic A., Jordan, Tom A., de Rydt, Jan, Fretwell, Peter T., Seddon, Samuel A., Becker, David, Hogan, Kelly A., Smith, Andrew M. and Vaughan, David G. (2019) Past and future dynamics of the Brunt Ice Shelf from seabed bathymetry and ice shelf geometry. The Cryosphere, 13. pp. 545-556. ISSN 1994-0440 &lt;a href=&quot;http://dx.doi.org/10.5194/tc-2018-206&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://dx.doi.org/10.5194/tc-2018-206&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15648" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-07-25T02:48:49.683" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16744" PostTypeId="1" CreationDate="2019-04-15T03:20:12.890" Score="6" ViewCount="844" Body="&lt;p&gt;It is well accepted that the outer core is made out of liquid iron and nickel, and as everything else it should tend to reach chemical equilibrium with its surrounding.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In particular, I would expect it to interact with the lower mantle through mixing and chemical reactions with the oxygen, silicates and other compounds. These interaction would result in the outer core slowly dissolving away into the mantle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would also expect this to happen in spite of the density gradient, that anyway should be less relevant down there, where the acceleration of gravity is much smaller than in the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why this dissolution doesn't happen? Why is the outer core stable?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a bonus question inspired by &lt;a href=&quot;https://earthscience.stackexchange.com/q/16730/11908&quot;&gt;this one&lt;/a&gt;: would any other blob of molten iron be stable anywhere in the mantle?&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="6129" LastEditDate="2020-05-07T11:31:03.427" LastActivityDate="2020-06-23T11:40:16.900" Title="Why doesn't the Earth's outer core dissolve into the mantle?" Tags="|geophysics|geochemistry|core|mantle|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16745" PostTypeId="1" CreationDate="2019-04-15T03:44:01.497" Score="1" ViewCount="408" Body="&lt;p&gt;I was working on &lt;a href=&quot;https://www.sciencebuddies.org/science-fair-projects/project-ideas/Geo_p047/geology/how-acidic-waters-make-rocks-disappear#procedure&quot; rel=&quot;nofollow noreferrer&quot;&gt;this science project&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was on step 11, day. 4. Since day 2, I found out that my pH and the mass of the rock (limestone) &lt;strong&gt;stopped changing&lt;/strong&gt;. This project should proves acidic water makes rocks disappear. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think I did something wrong. Did I?  &lt;/p&gt;&#xA;" OwnerUserId="15667" LastEditorDisplayName="user12525" LastEditDate="2019-04-16T09:00:53.380" LastActivityDate="2019-04-16T16:37:46.373" Title="How acidic waters make rocks disappear?" Tags="|geochemistry|hydrogeology|limestone|underground-water|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16746" PostTypeId="2" ParentId="16737" CreationDate="2019-04-15T03:47:55.583" Score="0" Body="&lt;p&gt;The previous record-holder, P. fumarii, could live at temperatures as high as 113 °C (235 °F), well above the boiling point of water. But the new microbe, for now called “Strain 121,” thrives at 121 °C and can even survive for two hours at 130 °C.&lt;/p&gt;&#xA;" OwnerUserId="15667" LastActivityDate="2019-04-15T03:47:55.583" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16750" PostTypeId="2" ParentId="5313" CreationDate="2019-04-16T03:44:27.453" Score="0" Body="&lt;p&gt;The color of a cloud depends primarily upon the color of the light it receives. The Earth's natural source of light is the sun which provides 'white' light. White light combines all of the colors in the 'visible spectrum', which is the range of colors we can see.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each color in the visible spectrum represents electromagnetic waves of differing lengths. The colors change as the wavelength increases from violet to indigo to blue, green, yellow, orange, red and deep red.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Visible light is only a small portion of the full electromagnetic spectrum.&#xA;As a light wave's length increases, its energy decreases. This means the light waves that make up violets, indigo and blue have higher energy levels than the yellow, orange and red.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One way to see the colors of sunlight is by the use of a prism. The velocity of light decreases slightly as it moves into the prism, causing it to bend slightly. This is called refraction. The degree of refraction varies with the energy level each wave.&lt;/p&gt;&#xA;" OwnerUserId="15667" LastActivityDate="2019-04-16T03:44:27.453" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16751" PostTypeId="1" CreationDate="2019-04-16T04:04:53.283" Score="1" ViewCount="61" Body="&lt;p&gt;In &quot;The Great Dying&quot; &lt;a href=&quot;https://www.nationalgeographic.com/science/prehistoric-world/permian-extinction/&quot; rel=&quot;nofollow noreferrer&quot;&gt;About 250 million years ago, at the end of the Permian period, something killed some 90 percent of the planet's species. Less than 5 percent of the animal species in the seas survived. On land less than a third of the large animal species made it.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I presume the surviving species were reduced in number. Is there any information on by how much, or how much the total biomass was reduced?&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-04-16T04:04:53.283" Title="&quot;Great Dying&quot; reduction in biomass" Tags="|paleontology|mass-extinction|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16753" PostTypeId="1" AcceptedAnswerId="17950" CreationDate="2019-04-16T07:22:51.123" Score="8" ViewCount="74" Body="&lt;p&gt;The New York Times article &lt;a href=&quot;https://www.nytimes.com/2019/04/12/science/yellowstone-volcano-warm-spot.html&quot; rel=&quot;noreferrer&quot;&gt;It’s Warm and Stealthy, and It Killed Yellowstone Trees and Turned Soil Pale&lt;/a&gt; describes an even that took place over the past few decades where a small and well-defined forested spot in Yellowstone National Park underwent some change, killing all of the trees growing there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dr3tl.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dr3tl.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Credit: United States Geological Survey&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The article explains the possible explanation that the trees died from changes in subsurface water chemistry.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Dr. Vaughan perused the aerial shots taken of the suspicious region. In 1994, nothing seemed amiss and trees were growing healthily. However, from then through 2017, trees had perished, and the soil had turned a sickly off-white color. The only reasonable explanation was that a new thermal area had been covertly growing in the region since the late-1990s, altering the ground’s chemistry with its superheated fluids.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Parenthetically speaking, to me &quot;superheated fluids&quot; sounds like something that could kill trees thermally, even without chemistry. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would heating like this show up as a hot spot in thermal IR Earth imaging? Or is this likely to have been too deep to result in a significant surface temperature change?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Google maps screen shot centered at &lt;code&gt;44.663584 N, 110.278843 W&lt;/code&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OdIy6.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OdIy6.jpg&quot; alt=&quot;Yellowstone West Tern Lake &amp;lt;code&amp;gt;44.663584 N, 110.278843 W&amp;lt;/code&amp;gt;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2019-09-09T18:04:00.270" Title="Would the subsurface event leading to tree death at West Tern Lake in Yellowstone be visible in thermal imaging?" Tags="|groundwater|earth-observation|geothermal-heat|underground-water|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16754" PostTypeId="1" AcceptedAnswerId="16757" CreationDate="2019-04-16T12:28:13.410" Score="1" ViewCount="124" Body="&lt;p&gt;I'm looking for time series of wave height/ period, velocity currents and wind speed/direction specifically for the Qiangzhou strait in China.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Global data sets could also work.&lt;/p&gt;&#xA;" OwnerUserId="15677" LastEditorUserId="2470" LastEditDate="2019-04-16T16:38:59.753" LastActivityDate="2019-04-16T16:38:59.753" Title="Where can I find wave height/period, current velocity and wind speed/direction data at the Qiangzhou strait in China?" Tags="|wind|ocean-currents|waves|open-data|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16755" PostTypeId="1" CreationDate="2019-04-16T14:11:15.273" Score="1" ViewCount="28" Body="&lt;p&gt;In a paper I am reading, the authors note &quot;large (5-7%) negative shifts in the oxygen isotopic composition of geologic proxy materials&quot; (Davis 2008, pg. 102) in several regional basins.  This is then interpreted by the authors as evidence of a significant tectonic change in elevation for the three basins being studied.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is regarding this scale of negative oxygen isotope shift (d18O).  How much change in temperature would 5-7% suggest?  Is there some online resource that might help me understand these factors of global climate versus local climate versus local tectonics better, as related specifically to oxygen isotope ratios and any details of actual temperature that can be inferred.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If relevant, the ratios are being measured in chert.  The basins are all inland (western USA), in a fluvio-lacustrine environment that changes from open to closed various times.  The 5-7% change in one basin is from 22.5% to 14.6% between 42-37 Ma (pg. 110); the basin I am studying.  Another nearby basin, to the north, changes from 28.5% to 20.5% between 44.2-43.1 Ma (pg. 108).  The third basin, to the south, changes from 17.2% to 13.2% between 44-40 Ma (pg. 109).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source:&#xA;Steven J. Davis, Andreas Mulch, Alan R. Carroll, Travis W. Horton, C. Page Chamberlain; Paleogene landscape evolution of the central North American Cordillera: Developing topography and hydrology in the Laramide foreland. GSA Bulletin ; 121 (1-2): 100–116. doi: &lt;a href=&quot;https://doi.org/10.1130/B26308.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1130/B26308.1&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Available online at:  &lt;a href=&quot;https://www.academia.edu/17709420/Paleogene_landscape_evolution_of_the_central_North_American_Cordillera_Developing_topography_and_hydrology_in_the_Laramide_foreland&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.academia.edu/17709420/Paleogene_landscape_evolution_of_the_central_North_American_Cordillera_Developing_topography_and_hydrology_in_the_Laramide_foreland&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15678" LastActivityDate="2019-04-16T14:11:15.273" Title="How do you interpret Oxygen Isotope changes?" Tags="|geochemistry|glaciology|sedimentology|paleoclimatology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16757" PostTypeId="2" ParentId="16754" CreationDate="2019-04-16T15:17:54.250" Score="2" Body="&lt;p&gt;You can retrieve that information from &lt;a href=&quot;https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-era5-single-levels?tab=overview&quot; rel=&quot;nofollow noreferrer&quot;&gt;ERA5 reanalisys data&lt;/a&gt;. It cover the whole world from 1979 until almost the present. The resolution is 0.25°x0.25° and includes many fields that characterize ocean waves. here is a list of available fields for download in the &quot;Ocean Waves&quot; section:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hwV9Q.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hwV9Q.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And there is of course, winds data as well.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2019-04-16T15:17:54.250" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16758" PostTypeId="2" ParentId="16745" CreationDate="2019-04-16T15:22:42.330" Score="1" Body="&lt;p&gt;First of all, the rocks do not disappear they dissolve, so they are still there only dissolved into the liquid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You are using an acid (vinegar), this has a low pH.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rocks you are using (limestone) they have a high pH (alkaline).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The alkaline rock you add to the acid will dissolve but only until the acid is neutralized. The reaction stops when the pH reaches close to 7,0.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you had used less limestone or more vinegar the rock will be fully dissolved but the pH of the liquid will stay low. To neutralize the vinegar you must then add more limestone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So you did nothing wrong except maybe using too little acid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will stop my answer here, but if you had taken this reaction one step further you would have made marble (the bubbling you might have seen was carbon dioxide CO2).&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="2470" LastEditDate="2019-04-16T16:37:46.373" LastActivityDate="2019-04-16T16:37:46.373" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16759" PostTypeId="2" ParentId="5313" CreationDate="2019-04-16T16:08:43.533" Score="3" Body="&lt;p&gt;The cloud is inherently white/gray (it's clear water droplets). It's &lt;em&gt;shadowed&lt;/em&gt; from the red light to the west, but &lt;em&gt;exposed&lt;/em&gt; to the blue light from the rest of the (apparently mostly clear) sky, so it is mostly illuminated with blue light, and that's what it will reflect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As another answer observed, there are also perceptual effects. Your eyes aren't colorimeters; put a gray object next to an orange expanse, and it will look bluish. In a photo, the effect may be less pronounced; that's why the photo looks &quot;washed out&quot; to you in comparison to your memory.&lt;/p&gt;&#xA;" OwnerUserId="13324" LastActivityDate="2019-04-16T16:08:43.533" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16760" PostTypeId="1" CreationDate="2019-04-16T19:18:13.667" Score="3" ViewCount="39" Body="&lt;p&gt;I've just been thinking a fair deal about ocean plastic and the ocean clean-up project. Is there something in saline water that changes the chemical composition of most plastics to make them pretty unusable in recycling or is there something else that makes ocean plastic overall a lost cause for recycling?&lt;/p&gt;&#xA;" OwnerUserId="15681" LastActivityDate="2019-04-16T19:18:13.667" Title="Does long-term exposure to ocean water change the chemical structure of plastic into ocean plastic?" Tags="|oceanography|pollution|plastic|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16761" PostTypeId="2" ParentId="12353" CreationDate="2019-04-17T00:14:45.253" Score="3" Body="&lt;p&gt;Based on the state of the discussion in the comments I was not sure whether this has an answer now, but I stumbled over it, and I think I can give a short answer from which one can learn a lot.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll base my discussion on polar &lt;span class=&quot;math-container&quot;&gt;$(\rho,\phi)$&lt;/span&gt; coordinates, for the sake of clarity. In classical mechanics we use for the position vector &lt;span class=&quot;math-container&quot;&gt;$$\vec r= r \vec{e}_r = r \; (\cos\phi, \sin\phi),$$&lt;/span&gt; because &lt;span class=&quot;math-container&quot;&gt;$\dot{\vec{e}}_r = \dot{\phi} \; (-\sin\phi, \cos\phi) = \dot{\phi} \; \vec{e}_{\phi}$&lt;/span&gt;. In 3D spherical coordinates, we need a few more of those identities, but the algebra remains the same. From this follows &lt;span class=&quot;math-container&quot;&gt;$$\dot{\vec r}=\dot{r}\vec{e}_r + r\dot{\phi}\vec{e}_{\phi} $$&lt;/span&gt; and finally&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\ddot{\vec r}=(\ddot{r}-r \dot{\phi}^2)\vec{e}_r + (r\ddot{\phi} + 2\dot{r} \dot{\phi})\vec{e}_{\phi} $$&lt;/span&gt;&#xA;where we have already taken into account the change of coordinates, as well as unit vectors.&#xA;The next step would decompose &lt;span class=&quot;math-container&quot;&gt;$\dot\phi$&lt;/span&gt; as &lt;span class=&quot;math-container&quot;&gt;$\dot\phi = \Omega + u/r$&lt;/span&gt;, whereas &lt;span class=&quot;math-container&quot;&gt;$$r\dot\phi^2 = r\Omega^2 + 2\Omega u + u^2/r$$&lt;/span&gt;&#xA;where we identify (in order of the terms) 1.) the centrifugal term, 2.) the coriolis term and 3.) the &quot;curvature/metric&quot; term. This procedure works wonderfully also in spherical coordinates and one recovers perfectly the terms that i.e. Holton or Vallis get in their books via lengthy and opaque 'proof-by-picture' methods.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm saying the latter because now I draw conclusions for the complete equations, from my derivations which was done from the incomplete ones:&#xA;Conclusions:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Centrifugal terms are not what meteorologists call 'curvature/metric' terms. They can seem the same, if one is sloppy and writes &lt;span class=&quot;math-container&quot;&gt;$\Omega=vr$&lt;/span&gt;. Or what is often done is in order to calculate the orbit of a satellite to set centrifugal force and gravity equal, whereas one uses &lt;span class=&quot;math-container&quot;&gt;$u^2/r$&lt;/span&gt;, which is in fact the 'curvature' not the centrifugal term. Also the physically metric term is already &lt;span class=&quot;math-container&quot;&gt;$r\dot{\phi}^2$&lt;/span&gt;, as this one arises from having a curved coordinate system.  &lt;/li&gt;&#xA;&lt;li&gt;As pointed out in the comments, the centrifugal term &lt;span class=&quot;math-container&quot;&gt;$r\Omega^2$&lt;/span&gt; is customarily hidden in meteorology with the gravity. We would suspect this happens also in your set, because the Coriolis term appears, which hints that the above computation has been carried out to first order and thus the centrifugal term must float around somewhere.&lt;/li&gt;&#xA;&lt;li&gt;The curvature terms are nowhere to be found in your set of equations. This is probably due to the terms simply being neglected. Also when viewn in their full form in spherical coordinates, they seem quite messy and I didn't find any convenient way of expressing them through a nice vector-or matrix operation. Therefore I strongly suspect, that people when giving the vectorial form of the NS equations usually neglect them, and only add them when presenting the NS equations in component form.&lt;/li&gt;&#xA;&lt;li&gt;The above minimalistic derivation makes it clear that the curvature, centrifugal and Coriolis terms originate from having a curved coordinate system. Any curved coordinate system is necessarily non-inertial. Thus in Cartesian coordinates, which are inertial, those terms must necessarily vanish.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="489" LastActivityDate="2019-04-17T00:14:45.253" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16763" PostTypeId="1" AcceptedAnswerId="16764" CreationDate="2019-04-17T10:05:28.640" Score="2" ViewCount="249" Body="&lt;p&gt;The register shows several supercontinents have been formed on Earth's History:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;The most recent supercontinent, Pangaea, formed about 300 million&#xA;  years ago (0.3 Ga). There are two different views on the history of&#xA;  earlier supercontinents. The first proposes a series of&#xA;  supercontinents: Vaalbara (c. 3.6 to c. 2.8 billion years ago); Ur (c.&#xA;  3 billion years ago); Kenorland (c. 2.7 to 2.1 billion years ago);&#xA;  Columbia (c. 1.8 to 1.5 billion years ago); Rodinia (c. 1.25 billion&#xA;  to 750 million years ago); and Pannotia (c. 600 million years ago),&#xA;  whose dispersal produced the fragments that ultimately collided to&#xA;  form Pangaea&quot;.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Supercontinent_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;Supercontinent Cycle, Wikipedia&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I would expect then a new supercontinent to form in some million years, but this implies Atlantic or Pacific Ocean, both with ocean-ridges and divergent margins, to disappear.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wich one will be closed and wich one will survive to Supercontinent Cycle?&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-04-17T11:13:09.807" LastActivityDate="2019-04-17T12:48:13.123" Title="Which ocean is going to be swallowed by the Supercontinent Cycle, Atlantic or Pacific?" Tags="|geology|geophysics|plate-tectonics|models|earth-history|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16764" PostTypeId="2" ParentId="16763" CreationDate="2019-04-17T12:48:13.123" Score="3" Body="&lt;p&gt;The pacific has already lost part its spreading center, north america has been pushed over it.. A few tiny non-contiguous plates like the  Juan de fuca plate is all that is left of the east pacific plate. in places like the san-andreas the north american plates has complete overridden the spreading center. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In truth there are four possible predictions for the future: &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0921818118302054&quot; rel=&quot;nofollow noreferrer&quot;&gt;Novopangea, Pangea Ultima, Aurica and Amasia&lt;/a&gt;. two predict the atlantic disappearing one predicts the arctic and the final predicts the loss of the pacific. I think the latter two are more likely given what we see in the north america/pacific interaction but this is just opinion, the truth is we don't know a lot about how oceanic plates disappear or how spreading centers die because by their very nature they do not leave much evidence behind. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HJRCN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HJRCN.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2019-04-17T12:48:13.123" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16767" PostTypeId="2" ParentId="12353" CreationDate="2019-04-17T16:43:53.667" Score="3" Body="&lt;p&gt;I have gone through both the  references - &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/1520-0493%281992%29120%3C2429%3ATEOJSC%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;The effect of jet streak curvature on kinematic fields&lt;/a&gt; and the background reference in that paper - &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/1520-0493%281981%29109%3C2118%3AIOTGIM%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Isolation of the inertial gravity component in a nonlinear atmospheric model&lt;/a&gt; and neither of those references mention any connection to a Cartesian based NS and defining curvature in that coordinate space. To me the curvature problem in meteorology is best studied(for localized air flow) in a &#xA;&lt;a href=&quot;http://tornado.sfsu.edu/Geosciences/classes/e260/CoordinateSystems/NaturalCoordinateSystem.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Natural Coordinate System&lt;/a&gt; , &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Natural_coordinates&quot; rel=&quot;nofollow noreferrer&quot;&gt;What are natural coordinates ?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given that premise I would like to talk about the &lt;a href=&quot;https://en.wikipedia.org/wiki/Frenet%E2%80%93Serret_formulas&quot; rel=&quot;nofollow noreferrer&quot;&gt;Frenet Serret formula&lt;/a&gt;. In this context the natural coordinate system has three orthogonal basis vectors(&lt;span class=&quot;math-container&quot;&gt;$e_s,e_n,e_z)$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$e_s$&lt;/span&gt; is the direction of the horizontal wind vector i.e. &#xA;  &lt;span class=&quot;math-container&quot;&gt;$$v_h = |v_h| * e_s $$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$e_s$&lt;/span&gt; is just the well known &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Streamline&quot; rel=&quot;nofollow noreferrer&quot;&gt;Streamline&lt;/a&gt; and &lt;span class=&quot;math-container&quot;&gt;$e_n$&lt;/span&gt; is the normal to the streamline. We also need to introduce the &lt;a href=&quot;https://en.wikipedia.org/wiki/Radius_of_curvature&quot; rel=&quot;nofollow noreferrer&quot;&gt;radius of curvature&lt;/a&gt; which is used in the Frenet Serret formulae. It must be noted that the curvature talked about in this answer is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Curvature&quot; rel=&quot;nofollow noreferrer&quot;&gt;extrinsic curvature&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because of the orthogonality &lt;span class=&quot;math-container&quot;&gt;$e_s \times e_n = e_z$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will first address AtmosphericPrisonEscape's question then proceed to answer OP's question. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Frenet Serret formula does include the rate of change of basis vectors. From a layman's perspective can you explain what is rate of change of basis vectors ? Well  meteorological problems can be defined in a Cartesian basis (x,y,z) that is &quot;fixed&quot; with respect to the fixed stars. So this system can be regarded as an inertial system for a earthbound observer. In this system there are no &quot;fictitious&quot; forces that arise due to the particular choice of coordinate system. Details about this &quot;fixed&quot; inertial frame are provided in the reference cited at the end of the answer in Chapter 1. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since meteorological observations are carried out in a rotating coordinate system  they are best described in a coordinate system that rotates with the earth. So Cartesian system moving point to point the basis vector remains fixed and not does not vary. OTOH in a earth like system (such as a sphere) we generally describe in terms of &lt;a href=&quot;https://en.wikipedia.org/wiki/Curvilinear_coordinates&quot; rel=&quot;nofollow noreferrer&quot;&gt;curvilinear coordinates&lt;/a&gt; whose basis vectors vary point to point. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mathematically in a stationary Cartesian system &lt;span class=&quot;math-container&quot;&gt;$ \frac{de_x}{dx}  = 0 $&lt;/span&gt; because the basis vectors are independent of position.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a general curvilinear system we let go of these assumptions and introduce the idea of curvature. So from a Frenet Serret perspective &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\frac{\partial e_s}{\partial n} = \frac{e_n}{R_n}$&lt;/span&gt; and similar other terms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now to answering OP's question. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we take this equation and differentiate it wrt time&#xA;&lt;span class=&quot;math-container&quot;&gt;$$v_h = |v_h| * e_s $$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;we get&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ \frac{dv_h}{dt} = e_s \frac{ d|v_h|}{dt} + |v_h|\frac{de_s}{dt}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As one can see here I am explicitly differentiating the basis vector &lt;span class=&quot;math-container&quot;&gt;$e_s$&lt;/span&gt; wrt time.&#xA;So the first term on the RHS is known as the tangential acceleration(because it is in the direction of the streamline) and the second term after a usage of the Frenet Serret formula(and adjusting few terms) can be equated to  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$|v_h|\frac{de_s}{dt} = e_n  \frac{v^2_h}{R_t}$$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$R_t$&lt;/span&gt; is the radius of &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Trajectory&quot; rel=&quot;nofollow noreferrer&quot;&gt;Trajectory&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second term is known as the centripetal acceleration and is perpendicular to the streamline. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now armed with this information we can attempt to answer all of OP's questions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Curvature of jet streaks can be used to study areas of &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Confluence&quot; rel=&quot;nofollow noreferrer&quot;&gt;confluence&lt;/a&gt; and &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Diffluence&quot; rel=&quot;nofollow noreferrer&quot;&gt;diffluence&lt;/a&gt;. &#xA;All one has to do is take the divergence of the horizontal wind vector. Keeping in mind that the gradient and the wind vector need to be expressed in natural coordinates. In the area of diffluence the radius of curvature is positive and negative in the area of confluence. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Finally the issue of &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Cyclostrophic_wind&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cyclostrophic balance&lt;/a&gt; can be easily derived by transforming the NS equation into natural coordinates as shown in this ESSE answer &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2392/do-tornadoes-have-eyes/2396#2396&quot;&gt;Eye of a tornado&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not going to derive it but just give OP enough clues so OP can derive it.&#xA; The normal component of the NS equation is equated to the normal component of the pressure gradient. I have already given the equation for the normal component of the NS equation above. If we equate those two we get the cyclostrophic balance as shown below&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$|v_h|\frac{de_s}{dt} = e_n  \frac{v^2_h}{R_t}$$&lt;/span&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{v^2_h}{R_t} = -\frac{1}{\rho}\frac{\partial p}{\partial n}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As one can see  the curvature of the jet streak influences the acceleration by the centripetal force.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt; - &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/0521809495&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dynamics of the atmosphere : A course in theoretical meteorology&lt;/a&gt; Chapter 8. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-04-28T08:57:33.020" LastActivityDate="2019-04-28T08:57:33.020" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16769" PostTypeId="2" ParentId="580" CreationDate="2019-04-17T18:47:32.063" Score="0" Body="&lt;p&gt;It doesn't.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Based on observing this and other slow motion videos of cloud-earth lightning I observe the following:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Some low-intensity &quot;pilot lightning&quot; starts in the cloud, usually only at one point or at most a few points, and propagates in many directions away from that point, branching out much like a river delta or a tree branch.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The general direction of propagation is towards the ground, but not very strongly. The most consistent trait of the movement is &lt;em&gt;away from the origin&lt;/em&gt;, but not even that is absolute (there are a few loops and upward branches).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Once one of the branches touches or gets close to the ground an intense arc forms between that point on the ground and the origin of the &quot;pilot lighning&quot;. &lt;strong&gt;There is no clear indication of a direction,&lt;/strong&gt; partly because of the unavoidable camera overload.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Hypothesis&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The pilot lightning starts where the gradient of the inhomogeneous electric field is steepest, somewhere close to the concentrated collection of charge in the cloud. It does not start on the ground because the ground conducts comparatively well so that the charges dissipate, lowering the electric field strength.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The pilot lightning's propagation is driven by two factors: The electric field and a feedback mechanism. The feedback happens because the plasma corridor created by the emerging lightning bolt conducts electricity very well and thus facilitates propagation once it has started: Electrons and ions are accelerated and extend the corridor at its front. Apparently there is a chaotic element to this, possibly because turning air into plasma is an explosive process. This multi-directional explosive expansion is also responsible for the branching.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That the lightning roughly follows the field gradient explains the general direction. The feedback sustains the lightning once it has started. The explosive expansion of the heated air explains its chaotic parts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When one of the pilot lightning branches gets close enough to the ground that an arc to the ground is completed there is a completely conductive connection between the separated charges which will lead to the runaway discharge known as a lightning bolt. (It's a runaway process because higher currents increase the arc's conductivity by turning more air into plasma, so the current grows until the charges are exhausted.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;I do not think that the eventual main lightning bolt has a different &quot;direction&quot; than the pilot lightning,&lt;/strong&gt; and I cannot find observational evidence.  Even at 100,000 frames per second the intensifying &lt;a href=&quot;https://youtu.be/qQKhIK4pvYo&quot; rel=&quot;nofollow noreferrer&quot;&gt;appears instantaneous&lt;/a&gt;, and the main bolt is so bright that cameras are overloaded. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It may appear to the human perception as a &quot;back strike&quot; because it starts once the pilot lightning touches ground, much like a bounce-back event. But I think it's just that suddenly a lot of charges flow where only few charges were flowing a millisecond earlier, in the same direction.&lt;/p&gt;&#xA;" OwnerUserId="5396" LastActivityDate="2019-04-17T18:47:32.063" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16770" PostTypeId="1" CreationDate="2019-04-17T22:13:33.433" Score="3" ViewCount="28" Body="&lt;p&gt;I know that downscaled income data existed for The Special Report on Emissions Scenarios (SRES) Scenarios for IPCC's climate change scenarios. (&lt;a href=&quot;http://ciesin.columbia.edu/datasets/downscaled/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://ciesin.columbia.edu/datasets/downscaled/&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the successor of SRES scenarios, Representative concentration pathways (RCP), is there any downscaled dataset? &lt;/p&gt;&#xA;" OwnerUserId="1141" LastActivityDate="2019-04-17T23:42:37.083" Title="Is there any downscaled income data for representative concentrations pathways?" Tags="|climate-change|geography|database|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16775" PostTypeId="2" ParentId="16038" CreationDate="2019-04-19T03:24:48.620" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;SANDIA REPORT“&lt;a href=&quot;https://docsbay.net/the-arctic-coastal-erosion-problem&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Arctic Coastal Erosion Problem&lt;/a&gt;”by Sandia National&#xA;  Laboratories, SAND2016-9762, September,2016&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&quot;One-third of the coastline in the world is Arctic permafrost [Lantuit et al., 2012]. Despite&#xA;this sizeable proportion, a comprehensive understanding of erosion dynamics in the Arctic&#xA;has not yet emerged. Unfortunately, the majority of present knowledge regarding coastal&#xA;landscape evolution is confined to areas with temperate climates and non-cohesive sediments.&#xA;Oceanographic and geomorphic feedbacks in the Arctic may be complex, but the need to&#xA;interrogate these processes with physics-based modeling is becoming increasingly important.&#xA;This urgency is underscored by scientific work that demonstrates erosion rates for many&#xA;Arctic locations are increasing.&quot;&lt;/p&gt;&#xA;" OwnerUserId="15697" LastActivityDate="2019-04-19T03:24:48.620" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16777" PostTypeId="1" AcceptedAnswerId="17022" CreationDate="2019-04-19T15:28:42.783" Score="4" ViewCount="847" Body="&lt;p&gt;Is there a way to calculate the energy required to reduce the heat of oceans? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Am I wrong in thinking it is not as simple as reversing the calculation for specific heat of sea water?&lt;/p&gt;&#xA;" OwnerUserId="15701" LastEditorUserId="6467" LastEditDate="2021-12-17T01:11:39.313" LastActivityDate="2021-12-18T07:17:49.097" Title="How much energy would be required to actively reduce the temperature of the oceans of Earth by 1℃?" Tags="|climate-change|oceanography|water|geoengineering|" AnswerCount="3" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="16785" PostTypeId="1" CreationDate="2019-04-21T20:47:07.447" Score="4" ViewCount="662" Body="&lt;p&gt;Oxygen gas began to appear on the earth surface about 2 billion years ago by photosynthesis. Carbon Dioxide was converted into carbohydrates in the process. Where did these carbohydrates go? &#xA;If they were converted into coal, oil, and natural gas over millions of years, then by releasing them back to the atmosphere in a couple of hundred years by combustion, we are definitely changing the atmospheric composition. This will definitely change the climate. This argument for climate change seems easy to understand and bulletproof. However, I have not heard this argument mentioned by the media. Why?&lt;/p&gt;&#xA;" OwnerUserId="15715" LastEditorUserId="15715" LastEditDate="2019-04-23T00:30:10.073" LastActivityDate="2019-04-23T00:30:10.073" Title="3 Billion years ago, the earth is covered with Carbon Dioxide. Where did it go?" Tags="|atmosphere|climate-change|paleoclimatology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16786" PostTypeId="2" ParentId="15343" CreationDate="2019-04-22T03:42:24.323" Score="3" Body="&lt;p&gt;In the Nature Letter &lt;a href=&quot;https://docsbay.net/localization-of-the-gravity-field-and-the-signature-of-glacial&quot; rel=&quot;nofollow noreferrer&quot;&gt;Localization of the gravity field and the signature of glacial rebound&lt;/a&gt; by Mark Simons &amp;amp; Bradford H. Hager, Department of Earth Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, 4 December, 1997:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The negative free-air gravity anomaly centred on Hudson Bay, Canada, shows a remarkable correlation with the location of the Laurentide ice sheet, suggesting that this gravity anomaly is the result of incomplete post-glacial rebound1–3. This region, however, is also underlain by higher-than-average mantle seismic velocities, suggesting that the gravity low might result instead from dynamic topography associated with convective downwellings4–7. Here we analyse the global gravity field as a simultaneous function of geographic location and spectral content. We find that the Hudson Bay gravity low is unique, with anomalously high amplitude in the spectral band where the power from the Laurentide ice load is greatest2 and the relaxation times predicted for viable models of viscous relaxation are longest8 . We estimate that about half of the Hudson Bay gravity anomaly is the result of incomplete post-glacial rebound, and derive a mantle viscosity model that explains both this gravity signature and the characteristic uplift rates for the central Laurentide and Fennoscandian regions6 . This model has a jump in viscosity at 670 km depth, comparable to that in dynamic models of the geoid highs over subducted slabs4,9, but lacks a low-viscosity asthenosphere, consistent with a higher viscosity in the upper mantle beneath shields than in oceanic regions.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="15718" LastEditorUserId="6031" LastEditDate="2019-04-22T04:07:59.933" LastActivityDate="2019-04-22T04:07:59.933" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16787" PostTypeId="1" AcceptedAnswerId="17313" CreationDate="2019-04-22T06:58:13.750" Score="5" ViewCount="433" Body="&lt;p&gt;I thought I would be clever and add a new answer to &lt;a href=&quot;https://earthscience.stackexchange.com/q/15343/6031&quot;&gt;Hudson Bay Has Low Gravity?&lt;/a&gt; by using Wolfram Alpha to report gravitational acceleration for different locations, but it looks like my cleverness backfired.&lt;/p&gt;&#xA;&lt;p&gt;From &lt;a href=&quot;https://earthscience.stackexchange.com/a/15346/6031&quot;&gt;this answer&lt;/a&gt; I found &lt;a href=&quot;https://www.sciencephoto.com/media/159675/view&quot; rel=&quot;nofollow noreferrer&quot;&gt;this view&lt;/a&gt;, a subsection of which is cropped and shown below.&lt;/p&gt;&#xA;&lt;p&gt;I chose three points, the lowest, purple area near the West shore of the Hudson bay, a medium green-orange in lake Michigan near Chicago, and a high area just north of Iceland.&lt;/p&gt;&#xA;&lt;p&gt;I was surprised to see Wolfram report such a high gravitational acceleration for the Hudson Bay area at 9.85 m/s&lt;sup&gt;2&lt;/sup&gt;! I was expecting something substantially lower than 9.81 m/s&lt;sup&gt;2&lt;/sup&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question(s):&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Why is the gravitational acceleration for the west coast of the Hudson Bay so high from Wolfram Alpha?&lt;/li&gt;&#xA;&lt;li&gt;Roughly what acceleration should I be getting there?&lt;/li&gt;&#xA;&lt;li&gt;Could it be related to Wolfram Alpha's use of &lt;code&gt;EMG2008 12th order&lt;/code&gt; for a model?&lt;/li&gt;&#xA;&lt;li&gt;Why would it be reporting such large deviations in altitude for locations on water?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Here is the data:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;                              lat   lon    Total   vert dev  down     west    south    elev&#xA;Western Hudson Bay    'low'  60.9N 94.1W  9.85176  0.00302  9.85172  0.00967  0.02816   -22&#xA;Lake Mich. (~Chicago) 'med'  41.7N 87.3W  9.8188   0.00352  9.81874  0.01119  0.03274  +175&#xA;North of Iceland      'high' 66.6N 18.8W  9.86107  0.00259  9.86104  0.00845  0.02406  -445&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Wolfram Alpha links and raw data screen captures:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.wolframalpha.com/input/?i=gravitational+acceleration+at+60.9+North,+94.1+West&quot; rel=&quot;nofollow noreferrer&quot;&gt;60.9N 94.1W&lt;/a&gt;, &lt;a href=&quot;https://i.stack.imgur.com/CBl7t.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;West Hudson Bay (low)&lt;/em&gt;&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.wolframalpha.com/input/?i=gravitational+acceleration+at+41.7+North,+87.3+West&quot; rel=&quot;nofollow noreferrer&quot;&gt;41.7N 87.3W&lt;/a&gt;, &lt;a href=&quot;https://i.stack.imgur.com/WwjbX.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Lake Mich. (~Chicago) (med)&lt;/em&gt;&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.wolframalpha.com/input/?i=gravitational+acceleration+at+66.6+North,+18.8+West&quot; rel=&quot;nofollow noreferrer&quot;&gt;66.6N 18.8W&lt;/a&gt;, &lt;a href=&quot;https://i.stack.imgur.com/RUswv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;North of Iceland (high)&lt;/em&gt;&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/H9AQf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/H9AQf.png&quot; alt=&quot;gravitational variations&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="2470" LastEditDate="2023-09-27T06:08:19.883" LastActivityDate="2023-09-27T06:09:36.607" Title="Why doesn't Wolfram Alpha show low gravitational acceleration for the Hudson Bay?" Tags="|models|gravity|" AnswerCount="2" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="16788" PostTypeId="2" ParentId="16676" CreationDate="2019-04-22T09:52:34.300" Score="5" Body="&lt;p&gt;I think answering your questions in reverse will make more sense. The &quot;size&quot; of PM is typically the aerodynamic/inertial impaction size, as you guessed. My standard reference for this is &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pubmed/16002369&quot; rel=&quot;noreferrer&quot;&gt;this paper&lt;/a&gt;. Their figure 8 is a rough schematic of where particles of different size deposit in the lungs. Things with very large or very small inertial impaction size get filtered out by the nose and upper respiratory system. (The &quot;very small&quot; inertial impaction I would consider as the fuzzy boundary between particles and gases, and gases adsorb onto mucous.) It's the particles with an &lt;em&gt;aerodynamic&lt;/em&gt; size smaller than 2.5 microns that follow the airflow all the way from the nose and mouth into the lungs. So from a health perspective, aerodynamic size is what matters most.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly, most measurements of particulate matter filter them by size first, and those filters are based on how much they deflect when the airflow has to curve around a bend. So when measurements focus on PM2.5, that's also anything with aerodynamic radius less than 2.5 microns. They might later do optical scattering or other analysis, but AFAIK the aerodynamic filtering always comes first.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would say that PM2.5 is everything 2.5 microns and smaller, and PM10 includes all of PM2.5. When scientists want to differentiate the two, we usually use the terms for the different &quot;modes&quot;: coarse mode for ~1-10 micron, accumulation mode for ~.05-1 micron, and nucleation or Aitken mode for anything smaller. (Fine particulates are nucleation+accumulation.) The reason for PM2.5 including everything is that PM2.5 standards are focused on the mass concentrations, usually in micrograms/cubic meter. The total mass in the nucleation mode is typically negligible compared to the other two. (The &lt;em&gt;number&lt;/em&gt; concentrations particles in the nucleation and accumulation modes might be similar, but the masses are way different.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: I don't think I made this clear, but the reported air quality value for PM10 would include PM2.5, but if something is reported as &quot;coarse particulates&quot; it would be (PM10-PM2.5). You may also see a quantity TSP - total suspended particulates - which may include things even larger than PM10 that are being kicked up by particularly strong winds, or smoke and ash from nearby wildfires.&lt;/p&gt;&#xA;" OwnerUserId="1342" LastActivityDate="2019-04-22T09:52:34.300" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16790" PostTypeId="2" ParentId="16785" CreationDate="2019-04-22T10:40:52.373" Score="7" Body="&lt;p&gt;It went into:&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Limestone&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VuuDU.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VuuDU.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mostly made out of calcium carbonate (Ca&lt;strong&gt;C&lt;/strong&gt;O&lt;sub&gt;3&lt;/sub&gt;)&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Coal&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/w6vWo.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/w6vWo.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Oil and gas&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/09v64.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/09v64.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Living biomass&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RwJjC.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RwJjC.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Subducted into the mantle&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Occasionally coming back as diamonds&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SFf90.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SFf90.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or as volcanic gas&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gqKIl.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gqKIl.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;All images public domain from &lt;a href=&quot;https://pxhere.com/&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-04-22T10:40:52.373" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16791" PostTypeId="1" CreationDate="2019-04-22T14:47:40.393" Score="1" ViewCount="161" Body="&lt;p&gt;If an air mass that exists in North America starts moving south west or south east what kind of modification will affect it and how would you characterize it in it's final state?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My answer is that it would be a cP or an A air mass that would start moving so firstly it would be dry,cold and stable.During it's south movement it's temperature would decrease because of the latitude and also if it moves over any major lakes it would pick up some moisture.My problem is what happens when it reaches the Pacific ocean or the Atlantic ocean.I know it's moisture would increase but do I need to know if it's winter or summer to conclude if it's stable/unstable and cold/warm?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is my answer complete?&lt;/p&gt;&#xA;" OwnerUserId="15721" LastEditorDisplayName="user1066" LastEditDate="2019-04-25T02:00:32.113" LastActivityDate="2019-04-25T02:00:32.113" Title="Modification of an air mass" Tags="|meteorology|homework|synoptic|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16792" PostTypeId="1" CreationDate="2019-04-22T15:16:37.957" Score="7" ViewCount="104" Body="&lt;p&gt;Recently, &lt;a href=&quot;https://www.whoi.edu/oceanus/feature/a-rainfall-forecast-worth-its-salt/&quot; rel=&quot;nofollow noreferrer&quot;&gt;a new method&lt;/a&gt; has been proposed by &lt;a href=&quot;https://directory.whoi.edu/profile/rschmitt/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ray Schmitt (WHOI)&lt;/a&gt; and collaborators to use salinity patterns in the ocean to predict weather events (more specifically, rainfall) at scales from weeks to months. First, &lt;a href=&quot;https://dx.doi.org/10.1126/sciadv.1501588&quot; rel=&quot;nofollow noreferrer&quot;&gt;they were able to predict&lt;/a&gt; rainfall in the Sahara region. More recently, they have expanded their methodology to predict weather in the US and their method performed better than most of the traditional approaches (that included patterns like El Niño).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Predictions for  Apr 23 – May 6, 2019 (Source: &lt;a href=&quot;https://salientpredictions.launchrock.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Salient Predictions&lt;/a&gt;)&#xA;&lt;a href=&quot;https://i.stack.imgur.com/mtRZR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mtRZR.png&quot; alt=&quot;Predictions for Apr 23 – May 6, 2019&quot;&gt;&lt;/a&gt;&#xA;Considering that we are having more and better salinity information from satellites (&lt;a href=&quot;https://en.wikipedia.org/wiki/Soil_Moisture_and_Ocean_Salinity&quot; rel=&quot;nofollow noreferrer&quot;&gt;SMOS&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Soil_Moisture_Active_Passive&quot; rel=&quot;nofollow noreferrer&quot;&gt;SMAP&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;can we expect to have a better global seasonal rainfall prediction in the near future &lt;a href=&quot;https://salientpredictions.launchrock.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;as they described&lt;/a&gt;? &lt;/li&gt;&#xA;&lt;li&gt;What are the limitations of the approach? &lt;/li&gt;&#xA;&lt;li&gt;How far in the future can we extend the approach?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2019-04-26T03:48:56.933" LastActivityDate="2019-04-26T03:48:56.933" Title="Using salinity to predict rainfall" Tags="|meteorology|oceanography|weather-forecasting|rainfall|salinity|" AnswerCount="0" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="16793" PostTypeId="2" ParentId="12431" CreationDate="2019-04-22T16:25:57.863" Score="-1" Body="&lt;p&gt;The answer to your question: '...if my GPS says I am 100 km west of Greenwich Observatory, am I 100 km west of 0 0 0 or 100 km west of the line on the ground?'&#xA;is&#xA;You are 100km west of the reference meridian (0 deg 0 min 0 arc sec). The line on the ground is slowly moving with its tectonic plate by about 3cm/year to the northeast (that 3cm/yr is with respect to the best terrestrial reference frame, the ITRF, now ITRF2014).. Any line on the ground would have to be redrawn/reinstalled periodically if it were intended to remain an accurate depiction of the reference meridian's location on the ground. &lt;/p&gt;&#xA;" OwnerUserId="15722" LastActivityDate="2019-04-22T16:25:57.863" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16796" PostTypeId="2" ParentId="15948" CreationDate="2019-04-23T02:46:07.233" Score="1" Body="&lt;p&gt;Too long to post as a comment:&lt;/p&gt;&#xA;&lt;p&gt;Just published: Nature Geoscience &lt;a href=&quot;https://www.nature.com/articles/s41561-019-0355-1#MOESM2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geomagnetic jerks and rapid hydromagnetic waves focusing at Earth’s core surface&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Scrolling to the bottom of the page there are links to several short videos&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Abstract&lt;/p&gt;&#xA;&lt;p&gt;Geomagnetic jerks are abrupt changes in the second time derivative—the secular acceleration—of Earth’s magnetic field that punctuate ground observatory records. As their dynamical origin has not yet been established, they represent a major obstacle to the prediction of geomagnetic field behaviour for years to decades ahead. &lt;strong&gt;Recent jerks have been linked to short-lived, temporally alternating and equatorially localized pulses of secular acceleration observed in satellite data, associated with rapidly alternating flows at Earth’s core surface. Here we show that these signatures can be reproduced in numerical simulations of the geodynamo that realistically account for the interaction between slow core convection and rapid hydromagnetic waves. In these simulations, jerks are caused by the arrival of localized Alfvén wave packets radiated from sudden buoyancy releases inside the core.&lt;/strong&gt; As they reach the core surface, the waves focus their energy towards the equatorial plane and along lines of strong magnetic flux, creating sharp interannual changes in core flow and producing geomagnetic jerks through the induced variations in magnetic field acceleration. The ability to numerically reproduce jerks offers a new way to probe the physical properties of Earth’s deep interior.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Screen Shot from video #1, South America, circa 2016&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qGqFZ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qGqFZ.jpg&quot; alt=&quot;Screen Shot from video #1 Nature Geoscience  Geomagnetic jerks and rapid hydromagnetic waves focusing at Earth’s core surface&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Screen Shot from video #2&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Bq04b.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Bq04b.jpg&quot; alt=&quot;Screen Shot from video #2 Nature Geoscience  Geomagnetic jerks and rapid hydromagnetic waves focusing at Earth’s core surface&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-04-23T02:46:07.233" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16797" PostTypeId="2" ParentId="14560" CreationDate="2019-04-23T03:53:04.560" Score="1" Body="&lt;p&gt;This one has not been answered for a long time and I am going to summarize what I wrote in the comments. If I understood OP's question correctly I believe it is asking why &lt;a href=&quot;https://en.wikipedia.org/wiki/Potential_vorticity&quot; rel=&quot;nofollow noreferrer&quot;&gt;Potential Vorticity&lt;/a&gt;  is not shown in weather maps in a operational sense. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From this old(but still very useful reference) &lt;a href=&quot;https://apps.dtic.mil/dtic/tr/fulltext/u2/a207904.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Isentropic Potential Vorticity&lt;/a&gt; presuming &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Isentropic_surface&quot; rel=&quot;nofollow noreferrer&quot;&gt;isentropic surface&lt;/a&gt; are available operationally(AFAIK &lt;a href=&quot;https://rda.ucar.edu/thredds/catalog/files/g/ds084.1/2019/catalog.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;GFS provides isobaric PV surfaces&lt;/a&gt; &lt;strong&gt;Warning: You need to register to access the GFS link&lt;/strong&gt;) and &lt;a href=&quot;https://unidata.github.io/MetPy/latest/examples/isentropic_example.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;you need to interpolate from isobaric to isentropic&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Generally, as in constant pressure analyses, one would like to use at least two or three isentropic surfaces to analyze. However, unlike constant pressure analyses, one has to choose different isentropic levels depending upon the time of year. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;h2&gt;| Season     |   Low Level Potential Temperature  |&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;| Winter     |       290-295 K&lt;/p&gt;&#xA;&#xA;&lt;p&gt;| Spring     |      295-300 K&lt;/p&gt;&#xA;&#xA;&lt;p&gt;| Summer     |      310-315 K&lt;/p&gt;&#xA;&#xA;&lt;p&gt;|Fall         |      300-305 K &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;As one can see the correct isentropic surface to choose for a particular day can be quite a challenge. Also each part of the world may have it's own low level potential temperature complicating the problem.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Isentropic surfaces tend to intersect the ground at steep angles causing analyses near where they intersect the ground to be suspect. One must be careful about over-interpreting analyses made near where the isentropic surface intersects the earth. One would do best to choose isentropic levels which never reach the ground. However, to depict moist/dry tongues associated with synoptic scale systems one tries to go as low as possible without hitting the ground. So there are trade-offs; as usual, there are no quick-fixes!&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In my part of the world(tropics) an all season isentropic surface that does not intersect with the earth's surface globally is the 370 K isentropic level. From a isobaric perspective this turns out to be around 200 hPa from a perspective of climatology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As one can note this is at a very high level and corresponds to the level of the jet stream. As one analyzes lower isentropic levels one can see maps (you need 3-D to plot PV on an isentropic surface) that intersect the earth's surface and when that happens you need sophisticated extrapolation methods to calculate PV especially along orography(and these turn to be generally inaccurate). Over the tropics generally at lower isentropic levels PV surfaces tend to be perpendicular and their utility is restricted to as OP puts it to the inside of tropical cyclones and mesoscale convective systems. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;An example of using PV at lower levels of the atmosphere can be seen in this youtube video &lt;a href=&quot;https://www.youtube.com/watch?v=5vDUKimIUhQ&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sandy PV filaments&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-04-23T09:50:24.683" LastActivityDate="2019-04-23T09:50:24.683" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16798" PostTypeId="1" CreationDate="2019-04-23T08:30:26.433" Score="6" ViewCount="494" Body="&lt;p&gt;I'm a bit confused about how divergent boundaries between tectonic plates work, or just why plates move. I've read that these ridges that are in the place of divergent boundaries are created when magma arises from the mantle convection, probably powered by a mantle plume. This creates a hotspot, but in every illustration I have seen, they use these plumes or just the mantle convection force to explain why plates move apart each other:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sYc5h.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sYc5h.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here, that convection of the mantle is used to explain the formation of a ridge and why the plates move apart.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this is easy to understand with a cross section of the Earth like in that picture. But I can't wrap my head around the idea of this phenomenon creating the linear ridges we see extending across thousands of kilometers, like the East Pacific Rise. Because, that &quot;ridge&quot; we see in the above picture is just an elevation seen in a cross section of the Earth, that could very well be just a volcano or a single oceanic mountain, not a linear ridge of continental dimensions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I mean this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jIvlL.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jIvlL.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That can't be produced by a single mantle plume, right? Because a mantle plume is just in one spot. Is the convection force of the mantle rising across that entire line that is kilometers wide, creating a linear mantle plume? If that last one is the case, I would be even more confused about the shape of the convection cells in the mantle. Or are there multiple individual mantle plumes conveniently aligned across and beneath that ridge?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, I don't understand how the ridge is formed. Because the first picture helps me only to understand how a single elevation spot is created, like an underwater mountain, or a volcano, or even a volcanic island, but not an entire ridge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, I do know that the chain of Hawaiian islands up to Siberia was created due to the tectonic plate passing above a plume, or just a hotspot, and that created the entire &quot;ridge&quot;. But are all oceanic ridges formed in that same way? Due to a single plume creating a hotspot and the plate moving above it drawing the ridge as it passes? Or is this a different process? Because I also know this is happening in the middle of a plate, not a divergent boundary&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a picture about the Hawaiian island formation I read:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ldADF.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ldADF.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope someone can help me understand this a little better! Thanks!&lt;/p&gt;&#xA;" OwnerUserId="15727" LastActivityDate="2019-04-24T15:48:06.027" Title="How can linear oceanic ridges (like the East Pacific Rise) be explained by single point mantle plumes?" Tags="|plate-tectonics|ocean-ridge|mantle-plumes|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16799" PostTypeId="2" ParentId="16798" CreationDate="2019-04-23T11:34:02.230" Score="5" Body="&lt;p&gt;Hot spots and ridges are two different things.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hot spots stay in one place while the earth crust above them drifts and thus create a line of dormant volcanoes, they are a point features so to say.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ridges are places where the mantle convection wells up and spreads in two directions, gently pulling the earth crust with them and creating new crust where the magma wells up. Ridges may be described as linear features.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, without convection and thus without ridges, which form new earth crust, the hot spots wouldn't create a chain of volcanoes.&lt;/p&gt;&#xA;" OwnerUserId="14194" LastEditorUserId="14194" LastEditDate="2019-04-24T06:28:11.920" LastActivityDate="2019-04-24T06:28:11.920" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16802" PostTypeId="1" CreationDate="2019-04-23T14:41:36.590" Score="3" ViewCount="738" Body="&lt;p&gt;Carbon dioxide is the gas everyone talks about because of how much we emit, but it is the most influential greenhouse gas ? I know there are a lot of other gasses are way more potent to retain heat within the atmosphere (water vapor, methane) but exist in smaller quantities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Can we quantify the relative influence of each greenhouse gas over global warming  ?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="15730" LastEditorUserId="15730" LastEditDate="2019-04-25T00:55:56.487" LastActivityDate="2019-05-05T14:42:40.277" Title="Which greenhouse gas has the most influence over global warming?" Tags="|climate-change|climate|climate-models|greenhouse-gases|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="16804" PostTypeId="1" CreationDate="2019-04-24T04:44:20.137" Score="3" ViewCount="123" Body="&lt;p&gt;The university I'm a student at has been looking into Anaerobic digestion to reduce the environmental impact of the large amount of post-consumer food waste generated on campus. While this project has been a huge success, not only producing hydroponic slurry to grow vegetables for our food pantry, my group has noticed that it's been generating a lot of methane and nitrogen gasses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While the aforementioned methane can be cleanly burned to power the system, we've had a bit more trouble with the nitrogen, which is a far more potent greenhouse gas than the carbon dioxide generated via burning of methane.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: is there a way to root this gas through soil or some type of substrate that would allow for its quick fixation or sequestration into the soil allowing for the growth of crops? Most things I've been able to find only talk about low background quantities of N2, but not for NO or NO2 (except for their emissions, like from this &lt;a href=&quot;http://pods.dasnr.okstate.edu/docushare/dsweb/Get/Document-8686/&quot; rel=&quot;nofollow noreferrer&quot;&gt;OSU&lt;/a&gt; study).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this isn't the place to post this question, please let me know and I'll remove it, but I'm super appreciative for any help as we are a student-run project.&lt;/p&gt;&#xA;" OwnerUserId="16737" LastActivityDate="2019-04-24T04:44:20.137" Title="Sequestration of NO and NO2 Gasses into Soil" Tags="|climate-change|environmental-protection|nitrogen|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16806" PostTypeId="1" CreationDate="2019-04-24T13:12:53.053" Score="3" ViewCount="130" Body="&lt;p&gt;I understand that we are, in all likelihood, towards the end of an interglacial period (the holocene). What I'd like to know is, what has a stronger effect on global temperatures - the low point of the combined milankovich cycle, or CO2 levels of a certain amount (e.g. 600ppm, 1000ppm, etc)? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could current greenhouse gas levels (around 410ppm) prevent us from entering the next glacial period, or will we enter it no matter what we do?&lt;/p&gt;&#xA;" OwnerUserId="5381" LastActivityDate="2021-01-17T04:24:24.757" Title="Can CO2 / greenhouse gas levels override the effects of milankovich cycles?" Tags="|atmosphere|climate-change|carbon-cycle|environmental-protection|milankovitch-cycles|" AnswerCount="0" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="16807" PostTypeId="2" ParentId="14519" CreationDate="2019-04-24T13:31:41.210" Score="5" Body="&lt;p&gt;&lt;strong&gt;You are asking the wrong question&lt;/strong&gt;. The real question is why some podunk single city festival and not other larger more costly events, like space launches, national holidays, military campaigns, hurricanes, or a million other festivals. The conspiracy theorists likely picked that festival through data dredging, which means you are not going to disprove it by looking at the same data. If you compare enough festivals you will find some in which the weather does weird things, it is the law of large numbers in action.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;A festival that started in the 1970's is perfect for data dredging, there is a change in the underlying forces of weather in the 1970's.&lt;/strong&gt; The undeniable warming trend in global climate starts around the 1970's so if you divide your data sets before and after any point around that time the data will always show a significant difference, unless you correct for that shift. Without correcting for it all you are detecting is climate change, a known factor,n anthropomorphic factor at that. So really humans are altering the weather, just not in the way your friend thinks. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WKwsi.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WKwsi.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LVe7C.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LVe7C.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2019-04-26T15:20:38.483" LastActivityDate="2019-04-26T15:20:38.483" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16808" PostTypeId="2" ParentId="16798" CreationDate="2019-04-24T15:40:51.590" Score="2" Body="&lt;p&gt;hot spots help/control how spreading centers form but they are not what keeps them going.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you push on a thin amorphous material perpendicular to the surface they tend to crack/split at three cracks roughly ~120 degrees to each other. If you push at several points close enough to each other these cracks will tend to link up as long lines with 120 degree angle shifts spread throughout it. Rising mantle plumes create doming which splits in these 3 120 degree angles. These are called &lt;a href=&quot;https://en.wikipedia.org/wiki/Triple_junction&quot; rel=&quot;nofollow noreferrer&quot;&gt;triple junctions&lt;/a&gt;. Plate boundaries can be mapped by connecting the dots between known triple points, usually with two active and one dead fracture, continental crust boundaries in particular are dominated by these angles. Basically hotspots create uneven distribution of stress and weaknesses in the crust for convection currents to exploit, &lt;a href=&quot;https://www.nature.com/articles/s41598-018-33117-3&quot; rel=&quot;nofollow noreferrer&quot;&gt;affecting where the crust breaks&lt;/a&gt;. as the crust breaks and seperates the mantle can more easily push up creating a kind of feedback that turns single points into a line of spreading.  The smaller and more isolated the plume the more likely it will just stay just a hot spot. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note this is different than how hot spot induced island chains like Hawaii form. Which is caused by a single isolated hot spots punching a series of holes in crusts that is dragged over it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ashbU.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ashbU.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It helps if you remember mantle plumes and convection cells are not completely seperate things. Mantle plumes vary dramatically in size and distribution, if you have several mantle plumes together that is a large convection cell. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2019-04-24T15:48:06.027" LastActivityDate="2019-04-24T15:48:06.027" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16811" PostTypeId="1" AcceptedAnswerId="16812" CreationDate="2019-04-24T20:59:33.083" Score="3" ViewCount="436" Body="&lt;p&gt;What is it called for the part of a hill where it discontinuously gets steeper? If you climbing an easy slope and encounter a new steeper slope (such as formed by a rocky hill and accompanying soil slopes leading up to it), is this change called anything?&lt;/p&gt;&#xA;" OwnerUserId="16744" LastActivityDate="2019-04-28T03:37:16.887" Title="What is it called for the part of a hill where it discontinuously gets steeper?" Tags="|terminology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16812" PostTypeId="2" ParentId="16811" CreationDate="2019-04-25T02:17:49.467" Score="6" Body="&lt;p&gt;As far as I am aware there is no single term to describe the sudden &lt;strong&gt;change&lt;/strong&gt; in the gradient of a slope. Personally I would describe it simply as a &lt;em&gt;sudden increase in slope&lt;/em&gt;. However there are many words to describe the landforms that occur when gradient sharply increase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Terms such as &lt;em&gt;cliff, escarpment&lt;/em&gt; and &lt;em&gt;mountainside&lt;/em&gt; all describe the steep landform as whole. Whereas terms such as &lt;em&gt;flank&lt;/em&gt; or &lt;em&gt;face&lt;/em&gt; describe the side of the hill only with a steep gradient.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might find this link particularly helpful:&#xA;&lt;a href=&quot;https://www.macmillandictionary.com/thesaurus-category/british/parts-and-features-of-mountains-hills-and-cliffs&quot; rel=&quot;noreferrer&quot;&gt;https://www.macmillandictionary.com/thesaurus-category/british/parts-and-features-of-mountains-hills-and-cliffs&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="16749" LastActivityDate="2019-04-25T02:17:49.467" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16814" PostTypeId="2" ParentId="16422" CreationDate="2019-04-25T07:27:57.220" Score="1" Body="&lt;p&gt;There are more up-to-date datasets that are available after registration and acceptance of the respective data usage licences.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;E.g. two satellite-derived products&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;GSMaP &lt;a href=&quot;https://sharaku.eorc.jaxa.jp/GSMaP/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://sharaku.eorc.jaxa.jp/GSMaP/&lt;/a&gt;  &lt;/li&gt;&#xA;&lt;li&gt;TRMM 3B42RT &lt;a href=&quot;https://mirador.gsfc.nasa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://mirador.gsfc.nasa.gov/&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;For a more comprehensive overview, including evaluation against rain gauge data, see Beck et al. 2017.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Beck, H.E., Vergopolan, N., Pan, M., Levizzani, V., van Dijk, A.I., Weedon, G.P., Brocca, L., Pappenberger, F., Huffman, G.J. and Wood, E.F., 2017. Global-scale evaluation of 22 precipitation datasets using gauge observations and hydrological modelling. Hydrology and Earth System Sciences, 21(12), pp.6201-6217.&lt;/p&gt;&#xA;" OwnerUserId="13524" LastActivityDate="2019-04-25T07:27:57.220" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16815" PostTypeId="2" ParentId="16070" CreationDate="2019-04-25T08:18:22.903" Score="-1" Body="&lt;p&gt;Pollutions won't influence Freezing Rain. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Rosemary Peters '&lt;a href=&quot;https://docsbay.net/freezing-rain-facts&quot; rel=&quot;nofollow noreferrer&quot;&gt;Freezing Rain Fact&lt;/a&gt;',by April 25,2017&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Freezing rain starts its journey in the atmosphere as snow. The snow encounters a deep pocket of warm air, melts and becomes rain. The rain then passes through a layer of air close to the surface where the droplets cool to a temperature to just below freezing; however, the droplets don’t actually freeze over. When the “supercooled” raindrops hit the surface, like a road, tree or power line, they immediately freeze and form a thin glaze of ice.&lt;/p&gt;&#xA;" OwnerUserId="15718" LastActivityDate="2019-04-25T08:18:22.903" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16818" PostTypeId="1" CreationDate="2019-04-25T18:04:52.503" Score="4" ViewCount="349" Body="&lt;p&gt;I've got a friend who is a climate change sceptic.&lt;/p&gt;&#xA;&lt;p&gt;He argues that because all the CO&lt;sub&gt;2&lt;/sub&gt; in fossil fuels originally came from the earth's atmosphere. Then there can't be a problem releasing the CO&lt;sub&gt;2&lt;/sub&gt; back into the same atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;Intuitively it seems obvious to me that the quantities CO&lt;sub&gt;2&lt;/sub&gt; was stored up over a long time and now is being released back into the atmosphere in just a few short decades, which is causing problems, but his counter is that the earth is a closed system and so the total amount of carbon CO&lt;sub&gt;2&lt;/sub&gt; is constant. This part I'm less sure on but I have a feeling he must be wrong on that too.&lt;/p&gt;&#xA;&lt;p&gt;Can someone please explain where the flaw is his logic is? I want to debunk this in as scientifically accurate as way as possible.&lt;/p&gt;&#xA;" OwnerUserId="16756" LastEditorUserId="543" LastEditDate="2022-05-25T23:37:55.740" LastActivityDate="2022-05-25T23:37:55.740" Title="Total CO$_2$ is not constant?" Tags="|climate-change|co2|" AnswerCount="4" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16820" PostTypeId="2" ParentId="16802" CreationDate="2019-04-25T22:53:57.823" Score="1" Body="&lt;p&gt;The annual amount of CO2 we emit from using carbon that was in relatively long-term sequestration (coal, natural gas, petroleum) is on the order of 40 GT. To put this in perspective: the amount of food humans consume over the same period of time is on the order of 4 GT. Our CO2 production is an order of magnitude larger than worldwide food consumption. And the problem with it is that it takes weathering to remove it from the atmosphere - meaning it can stay around for millennia, and we're very definitely the ones extracting it from the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;H2O only stays in the atmosphere as long as the temperature allows. This means that it won't be the driving factor. There is a slight positive feedback with more H2O leading to a warming so it can hold more H2O, but there's also a negative feedback of about the same size with cloud formation reflecting the sunlight back to space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ozone in the upper atmosphere is responsible for the warming at the Stratopause. It's the reason why we have our atmosphere divided into layers with the Troposphere getting cooler with height, the Stratosphere getting warmer with increased height, and the Mesosphere getting cooler again with height. The Ozone absorbs the very energetic solar radiation that would otherwise destroy the DNA in your skin and cause cancers, but as it's a triatomic molecule, it's also very good at absorbing longwave radiation. In this case, a hole in the ozone above the Antarctic may be allowing slightly more longwave radiation to escape - and repairing the hole so we humans can survive might also be trapping additional heat. &lt;a href=&quot;https://climate.nasa.gov/faq/15/is-the-ozone-hole-causing-climate-change/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://climate.nasa.gov/faq/15/is-the-ozone-hole-causing-climate-change/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;CH4 stays in the atmosphere on the order of a decade before chemically reacting with oxygen molecules to become CO2 and H2O - but while it's present, the effect is about two orders of magnitude greater than that of CO2. But since the methane hydrates have been stable, they're not culpable in the warming. Although there are large quantities in tundra and ocean shelves, there's little point in making it the talking factor for anything except scare tactics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This page &lt;a href=&quot;https://www.epa.gov/ghgemissions/overview-greenhouse-gases&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.epa.gov/ghgemissions/overview-greenhouse-gases&lt;/a&gt; discusses the relative sizes emitted, but temper this with the measurements of these gases. CH4 us currently less than 2 ppmv and CO2 is over 400 ppmv, making it easily the biggest factor in our warming, and in fact, the warming from CO2 is what's causing the tundra to melt and the East Siberian Arctic Shelf (the largest on the planet) to warm and release its methane.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is why we concentrate on CO2 (it being the largest factor and also the only one we seem to have much control over).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hopefully this puts it into perspective, and you can do your yandex.com searches for more details.&lt;/p&gt;&#xA;" OwnerUserId="6313" LastActivityDate="2019-04-25T22:53:57.823" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16823" PostTypeId="2" ParentId="16718" CreationDate="2019-04-26T02:58:58.263" Score="3" Body="&lt;p&gt;The main reason why the International Date Line doesn't run down the 180° meridian as you have suggested is because all nations determine their own standard time zones, applicable only on land and adjacent territorial waters of that country. This date line is not based on international law, but on &lt;strong&gt;national laws&lt;/strong&gt;. The International Date Line is simply just an artificial-construct decided by cartographers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This means that any country near the date line can shift their national time to either side of the International Date Line if they wish to. There have been several historical examples of this occurring, such as when the Republic of Kiribati gained independence and acquired new islands as a part of its territory across the International Date Line. Obviously no nation wants different parts of its territory running on different dates so the government of that country will choose unilaterally to change their nations time-zone how they see fit. This creates the zig-zagging International Date Line we have today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Though, it is worth noting that in international waters time-zones do follow the 15° wide longitudinal lines as you have suggested as being ideal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You may find this link useful:&lt;a href=&quot;https://en.wikipedia.org/wiki/International_Date_Line&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/International_Date_Line&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="16749" LastActivityDate="2019-04-26T02:58:58.263" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16824" PostTypeId="1" CreationDate="2019-04-18T08:22:28.747" Score="3" ViewCount="124" Body="&lt;p&gt;I happened to take a photograph of a region of clouds ,and it seems to have a rather ordered arrangement ,if one looks towards the left of the image. Would there be a physical explanation for this or is it just chance?&#xA;&lt;img src=&quot;https://i.stack.imgur.com/rze7U.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="16767" OwnerDisplayName="Maan" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T21:11:42.663" LastActivityDate="2019-08-28T21:11:42.663" Title="Ordered arrangement of clouds" Tags="|meteorology|clouds|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16828" PostTypeId="2" ParentId="16818" CreationDate="2019-04-26T07:56:05.783" Score="5" Body="&lt;p&gt;First of all, earth doesn't have the same atmosphere it had, back when dinosaurs walked the earth, when most of current carbon-deposits formed. Some atmospheres earth had would even be toxic to humans. So, you're right, changing the atmosphere at the speed we're doing it is the problem, not the change in general.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Second, yes, earth is a rather closed system (with minor leaks, but anyway). Still, the timescale is important.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's go with a simple allegory:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Say, your friend had a pickup-truck (sorry, in my mind deniers all drive SUV or pickup^^). He uses it to transport a lot of material, e.g. paving stones. He knows, his truck is able to transport the total amount of stones (because he tried in the past, or because the specifications say so, or because someone told him, doesn't matter - like we know that earth's atmosphere held a lot more CO2 back in the day).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is he going to just dump the whole load at once from 2 m height into the back of his truck? I doubt so, because that would at least put some dents in the truck, or might even break the springs or an axle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;He'd pack the stones there manually and use enough padding to make sure nothing gets damaged or slips during the transport.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Currently we're dumping the stones all at once - and we'll surely break the vehicle, if we really continue. Earth, like the truck, needs to adapt to changes. And, as we know, geological timescales are a lot longer than we can truly observe - thus the current changes, though stretching over several generations, are way too fast for earth to really adapt.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Third: While earth is a closed system, states within a closed system may change. Say, you have a terrarium with some mice and a lot of wood. Then you burn the wood. The mice might survive the fire, but in the end will suffocate, since there is a lot more CO2 in their atmosphere now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, yes, releasing trapped carbon from fossile fuels and whatnot to the atmosphere doesn't change the overall mass of system earth. But it changes the state of the system - and we are depending on the current state of the system.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Also - I know, this is not scientifically - say we are wrong when it comes to greenhouse gasses, and he is right. What if we undertook a lot of effort to not to produce them, to clean our environment, to create less waste? We'd wake up one morning and be &quot;Dang, we made our planet worth living on again, how could we?!&quot; - Or, as one of my professors put it: &quot;Would you get on a plane when there is a 10 % chance, the plane is going to crash?&quot;&lt;/p&gt;&#xA;" OwnerUserId="14194" LastActivityDate="2019-04-26T07:56:05.783" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16829" PostTypeId="2" ParentId="14519" CreationDate="2019-04-26T15:36:53.820" Score="2" Body="&lt;p&gt;Let's have a closer look at the p-values in your analysis. By far the most significant effect in your model is the one captured by &quot;groupold&quot;, which indicates a significant difference between pre- and post-1972 temperatures. This points to the climate change effect, as noted in John's answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The next most significant factor we have is &quot;countdown&quot;, which indicates, not totally surprisingly, that temperatures tend to increase in the end of June and cool off into July.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, we have the interaction term, which is orders of magnitude less significant than the other factors. The most reasonable explanation for this is that climate change effects are most notable in the extremes of weather. As climate change raises the overall average temperature, it also pushes the extremes higher and lower. Climate change has a significant effect on temperatures, but that effect is even more pronounced in the height of summer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So no, the festival organizers haven't been using their WeatherSetter 9000 to make the last week of June warmer than average. Rather, climate change has made weeks since 1972 warmer than average, seasonal cycles have always made the last week of June warmer than average, and the climate change effect is especially strong at the extremes of weather.&lt;/p&gt;&#xA;" OwnerUserId="4971" LastEditorUserId="4971" LastEditDate="2019-04-26T15:44:46.477" LastActivityDate="2019-04-26T15:44:46.477" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16830" PostTypeId="1" CreationDate="2019-04-26T16:44:17.653" Score="1" ViewCount="72" Body="&lt;p&gt;In this paper &lt;a href=&quot;https://science.sciencemag.org/content/362/6419/eaat1327&quot; rel=&quot;nofollow noreferrer&quot;&gt;Temperature-dependent hypoxia explains biogeography and severity of end-Permian marine mass extinction&lt;/a&gt; is established  a link between an  increase of the global temperature by &lt;span class=&quot;math-container&quot;&gt;$10^\circ C$&lt;/span&gt; (in their simulation) and the &lt;strong&gt;Great Dying&lt;/strong&gt; global extinction via a global hypoxia. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to know how much the atmospheric pressure at sea level will increase when the oceans are heated &lt;span class=&quot;math-container&quot;&gt;$10^\circ C$&lt;/span&gt;   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The solubility of &lt;span class=&quot;math-container&quot;&gt;$O_2$&lt;/span&gt; in water is function of the temperature, atmospheric pressure and salinity and the paper only mention the temperature.  &lt;/p&gt;&#xA;" OwnerUserId="2613" LastActivityDate="2019-04-26T16:44:17.653" Title="How much increase in the atmospheric pressure when the global temperature is elevated by 10 C?" Tags="|temperature|mass-extinction|pressure|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16832" PostTypeId="1" CreationDate="2019-04-27T04:04:58.800" Score="1" ViewCount="380" Body="&lt;p&gt;Far below the earth's surface, hydrogen gas is continuously produced through &lt;a href=&quot;https://en.wikipedia.org/wiki/Serpentinite#Serpentinite_reactions&quot; rel=&quot;nofollow noreferrer&quot;&gt;serpentinization&lt;/a&gt;.  At least some fraction of this hydrogen remains trapped in the deep continental crust; indeed, Soviet geologists found that mud from the Kola Superdeep Borehole was &lt;a href=&quot;https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole#Research&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;boiling&quot; with hydrogen&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Are the Kola Borehole results unusual?  (That is, would an equally deep borehole somewhere else find just as much hydrogen?)&lt;/li&gt;&#xA;&lt;li&gt;If not, why is no one trying to mine this hydrogen and use it for, say, producing energy or powering cars?  Is it &quot;just&quot; a matter of economic infeasibility – for example, due to the extremely deep borehole required?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="15502" LastActivityDate="2019-04-27T04:04:58.800" Title="How much hydrogen can be extracted from the deep continental crust?" Tags="|geology|geochemistry|mining|resources|drilling|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16836" PostTypeId="2" ParentId="16811" CreationDate="2019-04-27T19:49:20.687" Score="3" Body="&lt;p&gt;It's called a 'break in slope' or a '&lt;a href=&quot;http://www.hyperdictionary.com/dictionary/break-in-slope&quot; rel=&quot;nofollow noreferrer&quot;&gt;break of slope&lt;/a&gt;'.&lt;/p&gt;&#xA;" OwnerUserId="4705" LastEditorUserId="2470" LastEditDate="2019-04-28T03:37:16.887" LastActivityDate="2019-04-28T03:37:16.887" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16837" PostTypeId="2" ParentId="7885" CreationDate="2019-04-27T20:03:10.847" Score="-3" Body="&lt;p&gt;All of you dont account sand from the bottom of the Mediterranean... More recently than we'd like to admit, thousands of years ago, meteorites smashed into the Greece/Israeli regions flooding North Africa and sending Atlantis to its doom in Mauritania.&#xA;Proof to my claim is being unearthed above the Dead Sea where sulfer, among other things, from a meteorite exploding upon entering the atmosphere has been found. An explosion of 10 megatons vaporized the Dead Sea region leaving the aftermath as told in the bible. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What makes you think another meteorite couldn't have done this? Throw a rock in a shallow puddle and see what happens to the sand where and around you made the impact... &lt;/p&gt;&#xA;" OwnerUserId="16774" LastActivityDate="2019-04-27T20:03:10.847" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16841" PostTypeId="1" CreationDate="2019-04-29T15:16:13.397" Score="1" ViewCount="90" Body="&lt;p&gt;What is the usual way to report surface  pressure in weather forecasts online, in smartphone apps, on TV/radio? Is it the actual local pressure or the sea-level adjusted value? Does it differ by country? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Update: For example, English Wikipedia article on &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_pressure&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atmospheric pressure&lt;/a&gt; says mean sea-level pressure is normally given in weather reports. And Russian Wikipedia &lt;a href=&quot;https://ru.wikipedia.org/wiki/%D0%90%D1%82%D0%BC%D0%BE%D1%81%D1%84%D0%B5%D1%80%D0%BD%D0%BE%D0%B5_%D0%B4%D0%B0%D0%B2%D0%BB%D0%B5%D0%BD%D0%B8%D0%B5&quot; rel=&quot;nofollow noreferrer&quot;&gt;article&lt;/a&gt; says the actual pressure is used. After some research I can say, that English weather websites I've seen report sea-level pressure and Russian weather websites mostly report actual pressure, but some of them report sea-level pressure. &lt;/p&gt;&#xA;" OwnerUserId="16739" LastEditorUserId="16739" LastEditDate="2019-05-02T16:03:55.213" LastActivityDate="2019-05-02T16:03:55.213" Title="Atmospheric pressure in weather forecasts: actual pressure or sea-level pressure" Tags="|meteorology|" AnswerCount="0" CommentCount="3" ClosedDate="2019-05-01T09:51:21.533" ContentLicense="CC BY-SA 4.0" />
  <row Id="16846" PostTypeId="2" ParentId="15107" CreationDate="2019-04-30T03:07:11.997" Score="0" Body="&lt;p&gt;&lt;a href=&quot;https://docsbay.net/straight-line-winds-vs-tornado&quot; rel=&quot;nofollow noreferrer&quot;&gt;Straight-Line Winds vs. Tornado&lt;/a&gt; point out that Straight-Line Wind from thunderstorms is much more common than damage from tornadoes. In fact, many confuse damage produced by straight-line winds and often erroneously attribute it to tornadoes,could speculate a tornado as dangerous as straight wind.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;IN - all wind flows INTO a tornado. Debris is often laying at angles&#xA;  due to the curving of the inflow winds &lt;a href=&quot;https://i.stack.imgur.com/OjrqH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OjrqH.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;OUT - all wind flows OUT from a downburst. Debris is often laying in&#xA;  straight lines (hence the term &quot;straight line winds&quot;) parallel to the&#xA;  outward wind flow &lt;a href=&quot;https://i.stack.imgur.com/ysBEZ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ysBEZ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; When&#xA;  extensive damage is noted, the National Weather Service may dispatch a&#xA;  damage survey team to determine the cause and nature of wind damage.&#xA;  Survey teams look for evidence of a circulation in debris fields to&#xA;  determine if the damage is straight-line winds or a tornado. Based on&#xA;  the degree of damage and damage indicators, a maximum wind speed is&#xA;  assigned to either the downburst or tornado.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="16784" LastActivityDate="2019-04-30T03:07:11.997" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16847" PostTypeId="1" CreationDate="2019-04-30T08:52:30.890" Score="1" ViewCount="216" Body="&lt;p&gt;I have got confused&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I took 100g soil in a funnel with filter paper. poured 100 ml water and collected the drained water in a calibrated cylinder.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Water added in funnel = 100 ml&#xA;Water collected in cylinder = 39 ml.&#xA;Water retained by soil = 61ml.&#xA;Thus soil WHC = 61ml/100g soil&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this same as Soil Pore volume? If not how should I calculate soil pore volume by water volume method?&lt;/p&gt;&#xA;" OwnerUserId="16785" LastActivityDate="2021-01-06T23:05:55.603" Title="Difference between soil Water Holding Capacity and soil pore volume?" Tags="|soil|soil-moisture|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16849" PostTypeId="1" CreationDate="2019-04-30T13:41:03.917" Score="1" ViewCount="27" Body="&lt;p&gt;Is there any way to compute snow-melt erosion with Universal Soil Loss Equation? How can I change rainfall erosivity factor to snow-melt erosivity?&lt;/p&gt;&#xA;" OwnerUserId="14926" LastActivityDate="2019-04-30T13:41:03.917" Title="Snowmelt erosion in USLE?" Tags="|soil|snow|erosion|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16850" PostTypeId="1" CreationDate="2019-04-30T13:49:28.253" Score="1" ViewCount="32" Body="&lt;p&gt;i've recently read &lt;em&gt;Climate policy implications of nonlinear decline of Arctic land permafrost and other cryosphere elements&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/s41467-019-09863-x&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/s41467-019-09863-x&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;the study estimates the potential costs of permafrost carbon feedbacks (PCF) and surface albedo feedbacks (SAF) under different emissions scenarios, while also taking into account the nonlinear nature of these feedbacks. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;conclusions are pretty straightforward, but i'm a bit confused by this figure: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2BGn6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2BGn6.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;what confuses me is this:&#xA;&quot;The nonlinear SAF is dominated by the decrease of its sea ice and land snow components (Fig. 2), resulting in less warming and negative GMST changes compared to the constant legacy SAF (Fig. 4b). The NDCs, NDCs Partial and BaU scenarios have the largest temperature increases and greatest decreases in land snow and sea ice SAF components, and thus show the greatest negative differences in GMST. The differences are the highest for BaU with nearly ice-free oceans and snow-free land even in winter after 2200. For the Zero Emissions, 1.5 °C, 2.0 °C and 2.5 °C scenarios, there are small increases in GMST for the entire time period due to the small peaks in the sea ice and land snow SAF components within this temperature range (Fig. 2). Overall, the constant legacy SAF appears reasonable for low emission scenarios, but overestimates GMST for high emission scenarios according to the current generation of climate models (CMIP5), with no apparent tipping points (Supplementary Fig. 4).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The nonlinear SAF can partially compensate for the PCF (Fig. 4c). For the high emission NDC, NDC Partial, and BaU scenarios, reduced warming due to the nonlinear response of the SAF partially cancels out warming due to the PCF. The effect is strongest for the BaU scenario, where the change in GMST from the legacy value switches sign from positive to negative. The SAF slightly amplifies the PCF for the low emission scenarios where the constant SAF forcing assumption remains valid (Zero Emissions, 1.5 °C, 2.0 °C and 2.5 °C). This means IAMs that do not include the PCF and assume a constant SAF will underestimate GMST by between 0.1 and 0.2 C for all but the highest emissions scenarios. These findings stemming from the nonlinearities both in the PCF and SAF have been overlooked in climate policy studies so far (Supplementary Note 5)41,42,43,44.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;a lead author explains it more simply:&#xA;&quot;These two components are set to peak for global temperatures within the range covered by the Paris Agreement, but if the climate warms further, the summer and spring sea ice and land snow covers will retreat further north and the albedo feedback will actually weaken.&#xA;[...]&#xA;High emissions scenarios, such as the current business as usual trajectory (BaU) -- expected to lead to around 4°C of warming by 2100 and cause by far the highest impacts on ecosystems and societies -- are also included. Under these, the strength of the PCF reaches its peak and does not increase further, while the continued weakening of the SAF gradually cancels the warming effect of the PCF.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedaily.com/releases/2019/04/190423114027.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedaily.com/releases/2019/04/190423114027.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;can someone explain the logic behind this - why does albedo feedback weaken under a high emissions scenario?&lt;/p&gt;&#xA;" OwnerUserId="16787" LastActivityDate="2019-04-30T13:49:28.253" Title="less albedo feedback under high (BAU) emissions?" Tags="|arctic|permafrost|" AnswerCount="0" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16851" PostTypeId="1" AcceptedAnswerId="16986" CreationDate="2019-04-30T13:52:21.760" Score="1" ViewCount="106" Body="&lt;p&gt;MASW is a common processing method for civil/geotechnical and even for oil/gas exploration (usually weathering static corrections) applications. In my experience, it seems to work well for &lt;em&gt;most&lt;/em&gt; environments and various subsurface conditions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The more I learn about FWI and MASW (for either Raleigh- or Love-waves), the more I realize that perhaps one day FWI methods will surpass any MASW processing because it attempts to overcome the limitations naturally imposed by MASW because of its inherent assumptions of subsurface conditions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To date, I cannot find a case study that compares both methods in a single environment. Also, I realize that deriving a reliable source function, recording the 3-D seismic wavefield, and overcoming the stability constraints associated with multiparameterization of FWI (especially for elastic wave phenomenon) is task to be handled with in the future. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;My questions are&lt;/strong&gt;: (1) Has anyone seen a paper dealing with comparing both methods - if so, where? (2) Will some form of FWI possibly surpass MASW workflows (e.g. ParkSeis or SurfSeis) in the near future?&lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2019-05-19T18:43:22.610" Title="Near-Surface Investigations: FWI vs. MASW" Tags="|geophysics|seismology|seismic|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16852" PostTypeId="1" CreationDate="2019-04-30T22:30:03.193" Score="3" ViewCount="1307" Body="&lt;p&gt;I do not understand how the reflected wave in a seismic survey has a steepening slope (slows down)  Please bear with me as I lay out my thoughts because I feel like I can grasp all of this except this one thing and I am struggling to reconcile it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a wave source produces waves at a point, as in a seismic geophysical survey there are 3 types of waves which we consider. There is the direct wave, the reflected wave, and the refracted wave. The reflected wave is never a first arrival. The refracted wave is first lagging behind the direct wave before reaching it at the crossover point and overtaking it. This makes sense because the refracted wave has a higher speed but it does not register its propagation at the first geophone until a certain time has elapsed since the initial pulse at the wave source; and the direct wave has been traveling from the source all the while. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;On an arrival time plot where time is the vertical y-axis and where distance is the horizontal x-axis we see that the refracted wave has an unphysical beginning at the y intercept and the direct wave begins normally from the origin. Where the intersect the refracted wave overtakes the direct wave. On this type of diagram the smaller the slope, the faster the wave. The slope of the refracted wave is 1/v2 and the slope of the direct wave is simply 1/v1.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Iefet.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Iefet.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I do not understand is why the reflected wave has a hyperbolic or curved trajectory on this plot. The slope steepens as it asymptotically approaches the direct wave. It makes sense that over long distances that the direct wave and the reflected wave should merge to almost being indistinguishable, but how is it possible that the reflected wave plot as a steepening slope i.e. is slowing down?  The reflected wave travels less  surface distance per unit time the smaller its angle of incidence ( meaning closer to the source) because it is more vertical than horizontal. Over time it becomes more horizontal and therefore more like a direct wave which takes a shorter and quicker path across the surface.  What am I missing? Why does the reflection plot curve as it does?&lt;/p&gt;&#xA;" OwnerUserId="14316" LastEditorUserId="14316" LastEditDate="2019-05-02T02:06:29.457" LastActivityDate="2022-02-25T07:19:34.723" Title="Travel Times for Seismic Wave Types - Why reflected t-x plot curves" Tags="|geophysics|seismology|waves|seismic|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16853" PostTypeId="1" CreationDate="2019-05-01T05:56:14.960" Score="1" ViewCount="49" Body="&lt;p&gt;A recent flood was due to combined effect of rainfall(precipitation) and reservoir storage. I have daily rainfall data and reservoir storage data. How can I correlate these two to get a statistical model? &lt;/p&gt;&#xA;" OwnerUserId="16789" LastActivityDate="2019-05-01T05:56:14.960" Title="Flood and Statistics" Tags="|hydrology|precipitation|flooding|dams|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16856" PostTypeId="2" ParentId="16852" CreationDate="2019-05-01T16:45:39.210" Score="3" Body="&lt;p&gt;This is conceptually relatively simple if you look at where the reflection (and refraction) happen, and in fact you have articulated the key concept in your question:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The reflected wave ...Over time it becomes more horizontal and therefore more like a direct wave which takes a shorter and quicker path across the surface. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is absolutely correct. So if you are close to the seismic source (distance a, where a is small), the direct wave is quickest, as the reflected wave has to first travel down to the boundary before being reflected back. It travels a little over 2b, where b is the depth of the boundary layer. That &quot;little over&quot; depends on the angle, which is related to the distance a.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an example, look at the image below, from &lt;a href=&quot;https://slideplayer.com/slide/5354822/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this presentation on reflected, refracted and diffracted waves&lt;/a&gt;. The 2nd of the reflected waves is not much larger than the first, however the direct wave has travelled 4 times as far.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lBAEG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lBAEG.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a is much larger than b, then that 2b portion becomes less and less significant, and in fact you can say the distance travelled by the reflected wave tends towards a.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the graph does not show that the velocity of the wave is slowing down, more that the distance relationship with the angle of reflection tends to an asymptote.&lt;/p&gt;&#xA;" OwnerUserId="755" LastEditorUserId="755" LastEditDate="2019-05-03T12:13:39.343" LastActivityDate="2019-05-03T12:13:39.343" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16857" PostTypeId="2" ParentId="16818" CreationDate="2019-05-01T20:38:06.177" Score="5" Body="&lt;p&gt;The total amount of carbon is constant, the total amount of CO2 rises, mainly due to the burning of fossil fuels. &lt;/p&gt;&#xA;" OwnerUserId="13524" LastActivityDate="2019-05-01T20:38:06.177" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16858" PostTypeId="2" ParentId="16818" CreationDate="2019-05-01T21:27:18.290" Score="2" Body="&lt;p&gt;&lt;strong&gt;If you put a blanket around yourself, you warm up.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sounds a bit silly, but this is the physics of GHG warming in a nutshell.&#xA;The atmosphere is transparent to optical radiation which provides nearly all the energy to be trapped.&lt;br&gt;&#xA;Therefore, when computing a GHG model, you can put the source of the heating actually onto the surface of Earth. The energy is then reprocessed into infrared radiation and tries to escape.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this situation, both your body and the Earths atmosphere try to radiate in the infrared, but with a blanket that heat cannot escape anymore.&#xA;No matter if the blanket was laying around somewhere else for thousands of years, in that moment it gets warm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is of course a flawed &lt;strong&gt;analogy&lt;/strong&gt;, the better one is the one of the greenhouse: Visible light can enter, providing heat, but cannot escape in the infrared, because the glass is intransparent to infrared.&#xA;The more &lt;span class=&quot;math-container&quot;&gt;$\rm CO_2$&lt;/span&gt; there is in the atmosphere, the more 'glass'. No matter if this glass was buried underground for ages, at this very moment it causes temperatures to rise enormously.&lt;br&gt;&#xA;Same story with why a car heats up into a death trap in summer, while the exterior of the car at the same moment doesn't.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your friend (and probably other climate denialists) confuse the Earth's mass balance with its energy balance. One doesn't have much to do with the other.&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="489" LastEditDate="2019-05-01T21:35:57.990" LastActivityDate="2019-05-01T21:35:57.990" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16860" PostTypeId="2" ParentId="15684" CreationDate="2019-05-02T19:12:41.857" Score="1" Body="&lt;p&gt;Disclaimer: I haven't watched the docudrama.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a comet impact, I think the &lt;em&gt;chemical&lt;/em&gt; effects (dumping poisonous gases into the atmosphere) would be completely overwhelmed by the &lt;em&gt;thermal&lt;/em&gt; effects (lots and lots of kinetic energy converted to heat).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Those poisonous gases would surely be converted to plasma and/or blasted out in the shockwave from the impact. Any that were still solid at the point of ground impact would be splashed out in all directions, where they would quickly mix into the (suddenly superheated) atmosphere. Carbon monoxide, methane, and ammonia could burn &lt;em&gt;once they COOLED enough&lt;/em&gt; to combine with atmospheric oxygen, but they'd already be diluted below toxic levels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The heat from the impact would also cause all these products to rise into the stratosphere as a giant mushroom cloud, &lt;em&gt;drawing in fresh air&lt;/em&gt; at its base.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, no, I don't see how this could be realistic. I'm &lt;em&gt;almost&lt;/em&gt; tempted to go look for the video to see just how bad it was... but not quite.&lt;/p&gt;&#xA;" OwnerUserId="13324" LastActivityDate="2019-05-02T19:12:41.857" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16861" PostTypeId="2" ParentId="16818" CreationDate="2019-05-03T07:23:50.013" Score="1" Body="&lt;p&gt;Something else to consider: the amount of energy we get from the sun is slowly increasing over the billions of years as the sun goes through its lifecycle, so when you go back to ancient atmospheres and find what we would consider very high concentrations of GHG like CO2, it was necessary at that time to keep the planet warm. You can't simply look at the atmosphere from half a billion years ago and compare it with the present without considering the solar output.&lt;/p&gt;&#xA;" OwnerUserId="6313" LastActivityDate="2019-05-03T07:23:50.013" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16862" PostTypeId="2" ParentId="15684" CreationDate="2019-05-03T14:57:19.587" Score="1" Body="&lt;p&gt;&lt;strong&gt;tl;dr&lt;/strong&gt; while the docudrama is over-dramatised, yes, this is possible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Simply put, we already have processes which do make air unbreathable in small or even large areas, from dust or poisonous gases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Typically these are volcanic in origin, with fine dust from some volcanoes causing breathing difficulties across large areas, and from gases (often sulphur-based) burning lung surfaces or excluding oxygen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Impact from a large body can definitely have outcomes in related areas - dust or gas output, and while the immediate impact has more of a destruction aspect, once that has passed, gas and dust can very much be an ongoing problem, possibly even a semi-permanent issue, if the impact opens up new volcanic activity along a fault.&lt;/p&gt;&#xA;" OwnerUserId="755" LastActivityDate="2019-05-03T14:57:19.587" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16864" PostTypeId="1" CreationDate="2019-05-04T03:53:38.063" Score="1" ViewCount="95" Body="&lt;p&gt;A lady was telling me that the lower clouds were contrails left from plane exhausts. I looked up and there were none I could see in the sky she pointed to Stratocumulus Clouds. I did not want to tell here she is wrong because planes don't cruise that low, but it did make me think.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can contrails and/or sound coming from the engines create clouds or rain early if the conditions are right?&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2019-05-06T22:55:57.237" LastActivityDate="2019-05-06T22:55:57.237" Title="Can airplanes trigger rain?" Tags="|clouds|atmospheric-chemistry|rain|particulates|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="16865" PostTypeId="1" CreationDate="2019-05-04T06:35:28.710" Score="2" ViewCount="251" Body="&lt;p&gt;Since there are only 400 ppm in the atmosphere how can a molecule, which doesn't generate heat but absorbs it, possibly have such a great heating effect on the other 999,600 molecules? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;During the Jurassic/Mesozoic era the density of CO2 was as high as 7000 ppm and the earth was lush with vegetation and animal life. Aren't we actually in an exceptionally low CO2 density, historically?&lt;/p&gt;&#xA;" OwnerUserId="16802" LastActivityDate="2019-05-05T02:32:19.630" Title="CO2 density, is it really a greenhouse gas?" Tags="|co2|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16869" PostTypeId="2" ParentId="16865" CreationDate="2019-05-04T16:17:25.847" Score="3" Body="&lt;p&gt;Yes, carbon dioxide truly is a greenhouse gas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With regard to the immediate greenhouse effect, 99.96% of the dry atmosphere might as well be vacuum. Nitrogen (N&lt;sub&gt;2&lt;/sub&gt;), oxygen (O&lt;sub&gt;2&lt;/sub&gt;), and argon are extremely weak greenhouse gases at the temperatures present in the atmosphere. The only greenhouse gases in our atmosphere are trace gases. (The most powerful greenhouse gas is water vapor, and that, too is a trace gas in our atmosphere.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The 99.96% of the atmosphere that doesn't directly participate in the greenhouse effect is however present. At sea level, a molecule of carbon dioxide will travel freely for about a tenth of nanosecond before colliding with another gas molecule. This mean time between collisions increases to a few tens of nanoseconds at the top of the troposphere. A greenhouse gas molecule such as CO&lt;sub&gt;2&lt;/sub&gt; that has just absorbed a thermal infrared photon will very quickly transfer that absorbed energy to the non-greenhouse gases that comprise the vast majority of the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2019-05-04T16:19:08.497" LastActivityDate="2019-05-04T16:19:08.497" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16870" PostTypeId="1" AcceptedAnswerId="16871" CreationDate="2019-05-04T16:21:51.627" Score="1" ViewCount="177" Body="&lt;p&gt;In the end of glacial periods there seems to be an increasing release of carbon dioxide as the global warming increase and at the end of these global warming periods the content of carbon dioxide in the lower atmosphere seems to decrease in correlation to the temperature. Except from the obvious that carbon dioxide is more soluble in cold water and perhaps that some carbon dioxide is trapped in glacial ices, which are the &lt;em&gt;known&lt;/em&gt; mechanisms?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fswUE.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fswUE.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="16809" LastEditorUserId="16809" LastEditDate="2019-05-05T01:47:38.803" LastActivityDate="2019-05-05T01:47:38.803" Title="Which are the mechanisms of the correlation between atmospheric carbon dioxid and global warming/cooling?" Tags="|climate-change|geochemistry|atmospheric-chemistry|climatology|co2|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16871" PostTypeId="2" ParentId="16870" CreationDate="2019-05-04T16:40:39.330" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Except from the obvious that carbon dioxide is more soluble in cold water and perhaps that some carbon dioxide is trapped in glacial ices, which are the known mechanisms?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Those obvious mechanisms, particularly the first, are the primary mechanisms. Atmosphere carbon dioxide content gradually drops to very low levels during a glaciation precisely because cold water can dissolve much more carbon dioxide than can warm water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the Milankovitch cycles reaches a stage where the Earth starts warming up at the end of a glaciation, the Earth's waters start warming up, too. The warmer waters cannot hold as much CO&lt;sub&gt;2&lt;/sub&gt; as they held during the glaciation. The CO&lt;sub&gt;2&lt;/sub&gt; comes out of solution, adding to the Milankovitch-driven warming. This is one of the key reasons why the exit from a glaciation is much more abrupt than is the entry into one.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Based on comments by the OP, the OP appears to doubt that carbon dioxide and other polyatomic gases are greenhouse gases. The three principal components of the dry atmosphere, nitrogen (N&lt;sub&gt;2&lt;/sub&gt;), oxygen (O&lt;sub&gt;2&lt;/sub&gt;), and argon, are not greenhouse gases. Electronically neutral monatomic gases and diatomic gases comprising two atoms the same substance have zero dipole moment. These gases have essential zero cross section to low energy (e.g., thermal infrared) photons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, polyatomic molecules have many more degrees of freedom than do the homogeneous diatomic molecules and monoatomic gases that comprise the bulk of our atmosphere. Some such as water vapor have a marked permanent dipole moment. Others such as carbon dioxide nominally have a zero dipole moment, but transients due to thermal vibrations can temporarily given them a non-zero dipole moment. The combination of increased degrees of freedom and a non-zero dipole moment make these polyatomic gases very good at absorbing some parts of the thermal infrared spectrum.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All other things being equal, adding greenhouse gases to the Earth's atmosphere increases the Earth's equilibrium temperature. It's important to note that this greenhouse effect is essential for life. Without it, the Earth would be a frozen icefall, from pole to pole. In fact, during the Cryogenian (850-635 million years ago) &lt;a href=&quot;https://www.giss.nasa.gov/research/features/201508_slushball&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Earth apparently was covered or nearly covered with ice from pole to pole&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The end of a glaciation adds significant portions of the two most important greenhouse gases to the Earth's atmosphere. Water vapor increases because a warmer atmosphere can hold more water vapor than can a cold one. Carbon dioxide increases because a warmer ocean can hold less carbon dioxide than can a cold one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While the OP asked about the end of a glaciation, the real question being asked was about what is happening now. What happened at the end of glaciations and what is happening now are one and the same thing. Adding greenhouse gases to the Earth's atmosphere increases the Earth's equilibrium temperature. The end of a glaciation added greenhouse gases to the Earth's atmosphere, making the subsequent warming very rapid. Humanity is adding greenhouse gases to the atmosphere, carbon dioxide in particular, resulting in an even more rapid warming than that that occurred at the end of a glaciation.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2019-05-04T19:08:26.180" LastActivityDate="2019-05-04T19:08:26.180" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="16873" PostTypeId="2" ParentId="16865" CreationDate="2019-05-05T02:17:02.627" Score="2" Body="&lt;p&gt;As long as homo sapiens have existed the rate of carbon dioxide haven't exceed 350 ppm until 1990. All now living species are adapted to this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is an enormous amount of energy from the sun that hits earth each second and if the same amount doesn't radiate from earth the temperature will raise (or lower), slow or fast. Carbon dioxide and water vapor are transparent for the high frequent radiation from the sun, but not from the low frequent radiation from the earth. That's why 410 ppm in december 2018 is alarming.&lt;/p&gt;&#xA;" OwnerUserId="16809" LastEditorUserId="16809" LastEditDate="2019-05-05T02:32:19.630" LastActivityDate="2019-05-05T02:32:19.630" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16874" PostTypeId="1" CreationDate="2019-05-05T04:28:54.920" Score="1" ViewCount="123" Body="&lt;p&gt;I've been recently introduced to the Holdridge life zones and their method of classification, and have been somewhat concerned/confused by the definitions of tropical rain forest as described by the system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From looking at the zone of tropical rain forest, as opposed to subtropical rain forest or tropical wet forest, the minimum annual precipitation for the category appears to be 8000mm/8m. However, I've also found a number of mentions that the Holdridge system considers a &quot;true tropical rainforest&quot; to have annual temperatures over 24 degrees Celsius and annual rainfall higher than only 2000mm/2m.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The former threshold seems extremely high - very, very few places on Earth, even looking specifically within regions in the Amazon or SE Asia, appear to experience 8000mm or more of annual rainfall. However, an area with above 24 degrees annual temperature and between 2000mm and 4000mm of annual rainfall would appear to be considered a &quot;tropical moist forest&quot; and between 4000mm and 80000mm a &quot;tropical wet forest&quot;, separate categories from the &quot;tropical rain forest&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This seems like a very simple definitional question, but I've been unable to find a clear, solid answer on it. Thus:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Is it correct that &quot;true tropical rainforest&quot; and &quot;tropical rain forest&quot; are not referring to the same thing, when discussing the Holdridge life zones classification?&lt;/li&gt;&#xA;&lt;li&gt;Are there any appreciable regions in the world that are considered &quot;tropical rain forests&quot; rather than &quot;tropical wet forests&quot;,  &quot;subtropical rain forests&quot;, etc. under the Holdridge classification? &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="16811" LastActivityDate="2019-05-05T04:28:54.920" Title="Does tropical rain forest as defined by the Holdridge Life Zone classification exist in any meaningful prevalence?" Tags="|climate|models|precipitation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16876" PostTypeId="1" CreationDate="2019-05-05T09:36:43.210" Score="1" ViewCount="364" Body="&lt;p&gt;I am using ERA-Interim data, e.g. total precipitation, and I want to take only observations over land areas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can I filter the ERA-Interim dataset of precipitation to get only observations in grid-points over land?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any specific method I should apply?&#xA;Maybe CDO can help?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks &lt;/p&gt;&#xA;" OwnerUserId="11493" LastEditorUserId="8396" LastEditDate="2019-05-07T13:57:17.490" LastActivityDate="2019-05-07T16:23:01.087" Title="ERA-Interim how to select only grid-points over land area?" Tags="|reanalysis|era|grid-spacing|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16879" PostTypeId="1" AcceptedAnswerId="16893" CreationDate="2019-05-05T23:48:29.347" Score="1" ViewCount="112" Body="&lt;p&gt;For example, on windy.com I see that there is a high pressure area to the west of Washington in the Pacific Ocean. What heuristic techniques could I use to guess if the high pressure area will migrate towards the city of Seattle. &lt;/p&gt;&#xA;" OwnerUserId="16818" LastActivityDate="2019-06-06T13:03:05.327" Title="How to predict when the pressure will change" Tags="|weather-forecasting|pressure|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16880" PostTypeId="1" CreationDate="2019-05-06T08:44:45.603" Score="1" ViewCount="64" Body="&lt;p&gt;We are living in a historical period of global warming since about 20,000 years ago. This global warming period is one of about ten in human history. Those periods may very well be forced to start by optimal orbital conditions, but seems to develop rapidly by amplifying feedback from carbon dioxide and other greenhouse gases. Typically, the warming peek is very spiky at a rate of carbon dioxide slightly below 300 ppm. The probability that this peek is correlated to actual orbital forcing seems to me therefore very low.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Strong &lt;a href=&quot;https://en.wikipedia.org/wiki/Extratropical_cyclone&quot; rel=&quot;nofollow noreferrer&quot;&gt;extratropical cyclones&lt;/a&gt; are known since before the extraordinary ppm values of today, at lower warming rates than the typical warming peaks. The enormous amount of energy from (historical) global warmings did partly result in kinetic energy in storms. I think this is demonstrated in the increasing damage from tropical storms and my question is if there are reasons why extratropical cyclones in future, nearer the peek, not could change the albedo by clouds and snow/ice to a rate that turn global warming into cooling?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question isn't about the actual rate of carbon dioxide, but about the cycles that preceded our glacial period. Neither the question concern orbital forcing as such, but the possibility that a period of very bad weather with much snow in the north at least for some time (centuries) can cause global cooling.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5dhbO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5dhbO.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Below the extratropical cyclone Oratia in western Europe in October 2000: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9r3hy.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9r3hy.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="16809" LastEditorUserId="16809" LastEditDate="2019-05-06T11:43:17.590" LastActivityDate="2019-05-06T11:43:17.590" Title="Can extratropical cyclones force global cooling?" Tags="|meteorology|geophysics|climate-change|glaciation|global-weirding|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="16881" PostTypeId="1" AcceptedAnswerId="16882" CreationDate="2019-05-06T10:57:31.247" Score="6" ViewCount="4377" Body="&lt;p&gt;The BBC News article &lt;a href=&quot;http://www.bbc.com/future/story/20190503-the-deepest-hole-we-have-ever-dug&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Deepest Hole we have Ever dug&lt;/a&gt; says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This is the Kola Superdeep Borehole, the deepest man made hole on Earth and deepest artificial point on Earth. The 40,230ft-deep (12.2km) construction is so deep that locals swear you can hear the screams of souls tortured in hell. It took the Soviets almost 20 years to drill this far, but the drill bit was still only about one-third of the way through the crust to the Earth’s mantle when the project came grinding to a halt in the chaos of post-Soviet Russia.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The first image below shows the top of the Kola Superdeep Borehole, and the caption says that it is welded shut.&lt;/p&gt;&#xA;&lt;p&gt;Is there any way to form a reasonable hypothesis what would happen if it were opened today? Would the 12 km deep well have filled with water, or helium, or natural gas, or is it likely to be filled with air? Would it be under tremendous pressure on the other side of the bolted-down cap?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GCWFf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GCWFf.jpg&quot; alt=&quot;Kola Superdeep Borehole BBC&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; The borehole still exists - but the entrance has been welded shut (Credit: Rakot13/CC BY-SA 3.0), &lt;strong&gt;below:&lt;/strong&gt; The borehole is located in the wilds of Russia's northern Kola Peninsula (Credit: Getty Images)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UgKbp.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UgKbp.jpg&quot; alt=&quot;Kola Superdeep Borehole BBC&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="2470" LastEditDate="2021-08-28T10:14:59.423" LastActivityDate="2022-08-30T00:27:46.800" Title="If the Kola Superdeep Borehole were opened today, what would come out of it?" Tags="|geology|crust|drilling|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16882" PostTypeId="2" ParentId="16881" CreationDate="2019-05-06T13:15:27.460" Score="1" Body="&lt;p&gt;The only reasonable hypothesis is that it is filled with whatever it was filled with when the well was sealed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A 12km long pipe with a sealed end is not going to have its contents replaced with something else easily. You could theorise that an intrusion of gas at the bottom opening of the pipe could expel liquid by replacement - possible, but slow.&lt;/p&gt;&#xA;" OwnerUserId="755" LastActivityDate="2019-05-06T13:15:27.460" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16885" PostTypeId="1" CreationDate="2019-05-06T22:31:35.007" Score="6" ViewCount="853" Body="&lt;p&gt;Whenever we are investigating multiple layer interfaces in a seismic reflection survey the root-mean-squared velocity is often employed to deduce travel time to a certain n-th layer and also to deduce velocity of any given interval. This is done because it is a way to account for refraction that is also occurring between layers which alters the reflection of a shot made through multiple layers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I don't understand is how do we know the travel times in any layer beforehand? How are we distinguishing between different travel times and assigning them to different layers we've distinguished? We need travel times of successive layers in order to compute the root-mean-square, but this is puzzling to me because how could you already know them?  Who is to say it is multiple and not just 1? or 3, or 5 or some arbitrary number? What about the arrivals to the geophones tell us this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't get how we know there are extra layers in the first place to which we must assign travel times, and when they do exist, from where do these travel times come?  I have included a graphic to help show what I mean. The more I think about this, the more I start to think I don't understand multiple layer seismic reflection in general. &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Source: UC Berkeley Dept. Earth &amp;amp; Planetary Science’s &lt;a href=&quot;https://rallen.berkeley.edu/teaching/&quot; rel=&quot;noreferrer&quot;&gt;Richard Allen&lt;/a&gt;’s  Applied Geophysics GEO594/GLE594  notes for &lt;a href=&quot;https://rallen.berkeley.edu/teaching/F04_GEO594_IntroAppGeophys/Lectures/L15_SeismicReflectionII.pdf&quot; rel=&quot;noreferrer&quot;&gt;Lecture 15: Seismic reflection - II&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rP38V.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rP38V.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14316" LastEditorUserId="6031" LastEditDate="2019-05-07T09:53:12.220" LastActivityDate="2020-02-13T21:02:35.290" Title="How does multiple layer seismic reflection work? How do we distinguish arrivals from different layers and their velocities?" Tags="|geophysics|seismology|waves|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16888" PostTypeId="2" ParentId="12283" CreationDate="2019-05-07T06:31:13.543" Score="-1" Body="&lt;p&gt;A hurricane take it's energy from warm surface water, which is then cooled down. Warm, humid air is rising up more than 10 km and releasing it's heat through condensation of water vapor into water droplets in deep thunderstorms. The released energy is transformed to kinetic energy, a major part as rising movement of moister and droplets in the thunderstorms and a minor part (1/400) as the horisontal winds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The effect of a normal hurricane is about 200 times the effect of the world-wide electrical generating capacity. And the clouds of the hurricane reflects sunlight with almost the same amount of energy. When the horisontal wind is ebbing out a four hundredth of the hurrican energy again is converted to heat energy, while the energy of the vertical winds is used to transport moister from the surface up to the troposphere (potential energy). The rain falling down also cooling the ground, first directly and then while evaporates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The netto of all cloud formation is cooling down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.aoml.noaa.gov/hrd/tcfaq/D7.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.aoml.noaa.gov/hrd/tcfaq/D7.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="16809" LastEditorUserId="16809" LastEditDate="2019-05-07T06:41:00.340" LastActivityDate="2019-05-07T06:41:00.340" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16889" PostTypeId="2" ParentId="13692" CreationDate="2019-05-07T09:02:09.387" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://docsbay.net/arid-lands-challenges-and-hopes&quot; rel=&quot;nofollow noreferrer&quot;&gt;ARID LANDS: CHALLENGES AND HOPES&lt;/a&gt; &lt;em&gt;by&lt;/em&gt; EARTH SYSTEM: HISTORY AND NATURAL VARIABILITY – Vol. III - &lt;em&gt;Arid Lands: Challenges and Hopes - Barakat H.N.&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Hyperarid zones cover 7.5% of Earth's land surface, arid zones cover&#xA;  12.1%, while semiarid zones are more extensive, occur in all continents, and cover 17.7% of Earth's land surface. The dry subhumid&#xA;  category covers 9.9% of Earth's land surface.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="16829" LastActivityDate="2019-05-07T09:02:09.387" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16890" PostTypeId="1" AcceptedAnswerId="16891" CreationDate="2019-05-07T09:36:15.467" Score="2" ViewCount="81" Body="&lt;p&gt;The &lt;em&gt;fascinating&lt;/em&gt; New York Times article &lt;a href=&quot;https://www.nytimes.com/2019/05/01/science/flames-chimaera-turkey-methane.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gas That Makes a Mountain Breathe Fire Is Turning Up Around the World&lt;/a&gt; talks about the &lt;em&gt;Flames of Chimaera&lt;/em&gt; and the &lt;em&gt;Deep Carbon Observatory&lt;/em&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;And a series of studies published by a group of international scientists known as the &lt;a href=&quot;https://deepcarbon.net/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Deep Carbon Observatory&lt;/a&gt; is showing that this source of gas is more common on our planet than previously known.&lt;/p&gt;&#xA;&lt;p&gt;“We have discovered these &lt;strong&gt;unusual types of methane&lt;/strong&gt; in many, many sites. It’s not a rare phenomenon,” said &lt;a href=&quot;http://roma2.rm.ingv.it/en/staff/77/giuseppe_etiope&quot; rel=&quot;nofollow noreferrer&quot;&gt;Giuseppe Etiope&lt;/a&gt;, a member of the group who helped discover &lt;a href=&quot;https://onlinelibrary.wiley.com/doi/full/10.1111/gfl.12106&quot; rel=&quot;nofollow noreferrer&quot;&gt;the cause of the flames of Chimaera in 2014&lt;/a&gt;. (emphasis added)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This question is about the possible sources of hydrogen that resulted in what the NYTimes calls  &amp;quot;unusual types of methane&amp;quot;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;For years, Deep Carbon Observatory researchers have collected and analyzed gas samples from hundreds of diverse sites. And using special tools to figure out where the methane came from, they’ve discovered Earth’s basic recipe: Take hydrogen from water. Mix with inorganic carbon from minerals or gas. Add another metal-rich mineral to get the process going, and voilà — abiotic methane.&lt;/p&gt;&#xA;&lt;p&gt;The hydrogen often comes from serpentinization, when water percolates usually through rocks from the mantle. But the recipe varies. Different sites may use different minerals or carbons sourced from their environments: &lt;strong&gt;Hydrogen may come from friction, or radiolysis, instead of serpentinization.&lt;/strong&gt; Temperatures may range from below 250 degrees Fahrenheit, which can still support life, to some 900 degrees Fahrenheit, which can’t. (emphasis added)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;em&gt;Serpentinization&lt;/em&gt; is nicely explained in @Gimelist's &lt;a href=&quot;https://earthscience.stackexchange.com/a/12958/6031&quot;&gt;excellent answer&lt;/a&gt; to the question &lt;em&gt;What is serpentinization, in the context of disappearance of surface water on Mars?&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; How can the hydrogen in this abiotic methane come from&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;em&gt;Friction&lt;/em&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;em&gt;Radiolysis&lt;/em&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Possibly helpful (Open Access):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Etiope, G. and Whiticar, M. J. 2019 &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0883292719300204&quot; rel=&quot;nofollow noreferrer&quot;&gt;Abiotic methane in continental ultramafic rock systems: Towards a genetic model&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Etiope, G. and Ionescu, A. 2014 &lt;a href=&quot;https://onlinelibrary.wiley.com/doi/full/10.1111/gfl.12106&quot; rel=&quot;nofollow noreferrer&quot;&gt;Low‐temperature catalytic CO2 hydrogenation with geological quantities of ruthenium: a possible abiotic CH4 source in chromitite‐rich serpentinized rocks&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-05-07T11:50:01.837" Title="How does friction and radiolysis provide hydrogen for &quot;unusual types of methane&quot;?" Tags="|geochemistry|hydrogeology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16891" PostTypeId="2" ParentId="16890" CreationDate="2019-05-07T11:13:44.793" Score="1" Body="&lt;p&gt;I found &lt;a href=&quot;https://www.frontiersin.org/articles/10.3389/fmicb.2016.00076/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper &lt;a href=&quot;https://www.frontiersin.org/articles/10.3389/fmicb.2016.00076/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;&lt;/a&gt; trying to understand what is radiolysis. The decomposition of water by ionization happens at basaltic aquifers on the seafloor, close to seabed. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Water radiolysis is the decomposition of water molecules by ionizing&#xA;  radiation produced during the decay of radioactive elements (Debierne,&#xA;  1914; Le Caër, 2011). The principal radioactive elements that produce&#xA;  ionizing radiation in basalt are uranium (238U and 235U), thorium&#xA;  (232Th), and potassium (40K), which collectively emit alpha (α), beta&#xA;  (β), and gamma (γ) radiation as they and their daughter nuclides&#xA;  decay. Transfer of energy from this radiation excites and ionizes&#xA;  water molecules, producing several chemical species: eaq-, HO•, H•,&#xA;  HO2•, H3O+, OH-, H2O2, and H2 (Spinks and Woods, 1990; Le Caër, 2011).&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;The oceanic basement contains the largest aquifer on Earth. Its&#xA;  fractured rock contains nearly 2% of Earth’s total volume of seawater&#xA;  (Johnson and Pruis, 2003). Although the extent of life and microbial&#xA;  activity in oceanic basement is not well known, a variety of evidence&#xA;  suggests that microbes reside within the aquifer (Cowen et al., 2003;&#xA;  Edwards et al., 2012; Jungbluth et al., 2013; Lever et al., 2013;&#xA;  Orcutt et al., 2013). Fisk et al. (1998) and Staudigel et al. (2008)&#xA;  report weathering textures suggestive of microbial alteration in&#xA;  subseafloor basaltic glass.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;For subseafloor environments, we are particularly interested in the&#xA;  production of the reductant H2. Many organisms catabolically utilize&#xA;  H2, &lt;strong&gt;including methanogens&lt;/strong&gt;, sulfate-reducers, iron reducers, and&#xA;  nitrate reducers (Fang and Zhang, 2011). &lt;strong&gt;There is evidence that some&#xA;  of these organisms, specifically sulfate reducers and methanogens, are&#xA;  active in subseafloor basalt&lt;/strong&gt; (Lever et al., 2013). Radiolysis&#xA;  undoubtedly occurs in subseafloor basalt, as both water and radiation&#xA;  are present. Edwards et al. (2012) suggested that in the old and&#xA;  relatively weathered basaltic basement of the South Pacific Gyre&#xA;  (SPG), &lt;strong&gt;radiolytic H2 may be the dominant electron donor&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Trying to understand how hydrogen can be formed by friction I found &lt;a href=&quot;http://www.jamstec.go.jp/jdb/ronbun/Ks00030222.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this other one &lt;a href=&quot;http://www.jamstec.go.jp/jdb/ronbun/Ks00030222.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;&lt;/a&gt; where the author asociates it to earthquakes, listing three possible origins for hydrogen and saying the frictional origin is still a not well known process. Apparently it happens at fault systems when there are mouvements on lithosphere:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In the last few decades, three different abiotic H2 generation&#xA;  processes have been proposed: &lt;/p&gt;&#xA;  &#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;(1) water–rock redox reactions, mostly under hydrothermal conditions    [Janecky and Seyfried, 1986; Coveney et al., 1987],&lt;/li&gt;&#xA;  &lt;li&gt;(2) radiolytic reactions of H2O [Savary and Pagel, 1997], and&lt;/li&gt;&#xA;  &lt;li&gt;(3) mechanoradical formation on wet fault surfaces during earthquakes    [Wakita et al., 1980].&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;  &#xA;  &lt;p&gt;H2 production by peridotite‐&#xA;  water and komatiite‐water hydrothermal reactions, as modern and&#xA;  ancient analogs, respectively, has been quantitatively estimated in&#xA;  laboratory experiments [Seyfried et al., 2007; Yoshizaki et al.,&#xA;  2009]. Radiogenic production of H2 is supported by the analysis of&#xA;  H2‐bearing fluid inclusions in quartz containing U‐bearing minerals&#xA;  [Dubessy et al., 1988], and has been quantitatively estimated in a&#xA;  laboratory g‐irradiation experiment [Lin et al., 2005]. The H2 flux&#xA;  per unit of surface area from redox reactions has been estimated to be&#xA;  3 × 10−4 mol/m2 yr from a 1 km column of mafic/ultramafic rock with 10&#xA;  wt% FeO [Sleep and Zoback, 2007], and the estimated flux from water&#xA;  radiolysis in the Witwatersrand basin, South Africa, is 8 × 10−6&#xA;  mol/m2 yr [Lin et al., 2005]. &lt;strong&gt;In contrast, the H2 flux associated with&#xA;  earthquakes and its significance in subsurface ecosystems has not yet&#xA;  been explored in either the field or laboratory.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;After making experimental flux calcs the paper says this mechanism may have been important for methanogens. And not only eartquakes but meteorite impacts too may have been a source of mollecular hydrogen for primigenious  life not only on Earth but on other planets.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Thus, &lt;strong&gt;seismic activity and the consequent release of H2 might have&#xA;  sustained subsurface microbial communities&lt;/strong&gt; as long ago as 3.8 Ga.&#xA;  Moreover, &lt;strong&gt;mechanoradical H2 generation can be induced by meteorite&#xA;  impacts as well as by earthquakes&lt;/strong&gt;, and thus might play an important&#xA;  role in the evolution of subsurface biosphere not only on Earth but&#xA;  also on other planets.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.frontiersin.org/articles/10.3389/fmicb.2016.00076/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;1 &lt;strong&gt;Dzaugis Mary E., Spivack Arthur J., Dunlea Ann G., Murray Richard W., D’Hondt Steven (2016)&lt;/strong&gt;. &quot;&lt;em&gt;Radiolytic Hydrogen Production in the Subseafloor Basaltic Aquifer&lt;/em&gt;&quot; &lt;strong&gt;Frontiers in Microbiology&lt;/strong&gt;, 7, ISSN=1664-302X&lt;/a&gt;   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2011GL048850&quot; rel=&quot;nofollow noreferrer&quot;&gt;2 &lt;strong&gt;T Hirose, S Kawagucci, K Suzuki (2011)&lt;/strong&gt; &quot;&lt;em&gt;Mechanoradical H2 generation during simulated faulting:&#xA;Implications for an earthquake‐driven subsurface biosphere.&lt;/em&gt;&quot; &lt;strong&gt;Geophysical research letters.&lt;/strong&gt;&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-05-07T11:50:01.837" LastActivityDate="2019-05-07T11:50:01.837" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16892" PostTypeId="1" CreationDate="2019-05-07T11:45:22.010" Score="1" ViewCount="84" Body="&lt;p&gt;I am using sea-ice data from the European Reanalysis from ECMWF (&lt;a href=&quot;https://www.ecmwf.int/en/forecasts/datasets/reanalysis-datasets/era-interim&quot; rel=&quot;nofollow noreferrer&quot;&gt;ERA Interim&lt;/a&gt;), but some grid cells over land have sea-ice information. Not a big issue so far, because spatial discretization must always lead to some discrepancy in land-sea mask. But these specific grid cells, those closest to the coast (or even on land) show very weird values sometimes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Should I just remove the first couple of grid cells, that are closest to the coast, of sea-ice data? Is this a well-known issue? Or should I just use another source of data? If so, which other source?&lt;/p&gt;&#xA;" OwnerUserId="8396" LastEditorUserId="13524" LastEditDate="2019-05-08T16:35:57.770" LastActivityDate="2019-05-08T16:35:57.770" Title="How reliable is sea-ice concentration (fraction) data in ERA-Interim?" Tags="|climate-models|reanalysis|sea-ice|coastal|era|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16893" PostTypeId="2" ParentId="16879" CreationDate="2019-05-07T12:45:36.633" Score="1" Body="&lt;p&gt;Predictability of weather and climate is currently an active and lively research topic. I will try to giove some (very)  brief information on how it is normally done.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The best idea would be to use a &lt;a href=&quot;https://www.google.com/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=3&amp;amp;cad=rja&amp;amp;uact=8&amp;amp;ved=2ahUKEwj3_L6VuYniAhUE36QKHVFUBzUQFjACegQIEBAK&amp;amp;url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FNumerical_weather_prediction&amp;amp;usg=AOvVaw3XJ5GLzTC0ZYqVDTTS63DH&quot; rel=&quot;nofollow noreferrer&quot;&gt;weather (atmospheric) model&lt;/a&gt;, which is a numerical model that solves the &lt;a href=&quot;https://en.wikipedia.org/wiki/Navier%E2%80%93Stokes_equations&quot; rel=&quot;nofollow noreferrer&quot;&gt;Navier-Stokes Equations&lt;/a&gt; to bring prognostic information of the atmospheric state, for the next couple of days. This allows us to get a reasonably good prediction of high-low pressure zones within a week or so, which I intend is your goal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since you mentioned &lt;a href=&quot;https://www.windy.com/?53.575,10.015,5&quot; rel=&quot;nofollow noreferrer&quot;&gt;Windy.com&lt;/a&gt;, this is already a good source of information on weather prediction, probably one of the best compilation of weather models you can get nowadays. In the bottom right corner of the screan in windy.com (if using a desktop), you will see the acronyms GFS, ICON and ECMWF, for example. These are three models developed by possibly the three best centers in the world (from the USA, Germany and UK, respectively). A similar user-friendly interface, focusing on GFS is available at &lt;a href=&quot;https://earth.nullschool.net/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth Nullschool&lt;/a&gt;. They all bring a timer, so that you can choose the time of your prediction. Since you are asking specifically about a pressure system, I will assume you know how identify it in the images provided by these interfaces. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The predictability of weather for the next few days is good, and the predictability of &quot;seasonal climate&quot; is not bad either. For some time scale in between (subseasonal), there has long been a &quot;&lt;a href=&quot;https://public.wmo.int/en/resources/bulletin/subseasonal-seasonal-prediction-project-bridging-gap-between-weather-and-climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;grey zone of predictability&lt;/a&gt;&quot;. This is where cutting-edge research in Climate Science currently takes place. Sources of predictability, generally comes from a thorough understading of climatic phenomena (e.g. &lt;a href=&quot;https://www.google.com/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=4&amp;amp;cad=rja&amp;amp;uact=8&amp;amp;ved=2ahUKEwj0_IG8toniAhUpNOwKHc60AwMQFjADegQIARAB&amp;amp;url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FEl_Ni%25C3%25B1o%25E2%2580%2593Southern_Oscillation&amp;amp;usg=AOvVaw029ewL2j9L2FyVyhsDyWSu&quot; rel=&quot;nofollow noreferrer&quot;&gt;ENSO&lt;/a&gt;, &lt;a href=&quot;https://www.google.com/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=1&amp;amp;cad=rja&amp;amp;uact=8&amp;amp;ved=2ahUKEwimmMTOtoniAhXLy6QKHaAZB7IQFjAAegQIAxAB&amp;amp;url=https%3A%2F%2Fen.wikipedia.org%2Fwiki%2FNorth_Atlantic_oscillation&amp;amp;usg=AOvVaw2ajMXPpiSD4hQP-AR7NsGn&quot; rel=&quot;nofollow noreferrer&quot;&gt;NAO&lt;/a&gt;) and their relationship with the predicted variable. The NAO is known to modulate weather in North America and Europe in the day-to-day time scale, for example. ENSO is the dominant factor for tropical latitudes, with a lower-frequency variability.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This type of research is normally done using numerical weather and climate models, not so different from the ones in windy.com, often combined with statistics. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To reed further in the &lt;a href=&quot;https://journals.ametsoc.org/doi/full/10.1175/JCLI-D-18-0389.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;seasonal&lt;/a&gt; and &lt;a href=&quot;https://journals.ametsoc.org/doi/full/10.1175/JCLI3654.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;decadal&lt;/a&gt; time scales. &lt;/p&gt;&#xA;" OwnerUserId="8396" LastActivityDate="2019-05-07T12:45:36.633" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16894" PostTypeId="2" ParentId="16876" CreationDate="2019-05-07T13:33:23.473" Score="2" Body="&lt;p&gt;The simplest way is to download another variable in which data is only available over the ocean, such as Sea Surface Temperature (SST). You should be able to download it in the very same way you do with precipitation (let us call it PREC hereafter).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then, you can use any software that handles this type of data (Matlab, Python, NCL, GrADS...) to mask out the ocean cells. The logics is to assign a missing value (NaN) in PREC, where SST is &lt;em&gt;not&lt;/em&gt; a missing value, to get the land-only PREC (PRECL). Or the other way around: keep the values of PREC where SST has missing values.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Imagine SST and PREC are 2D fields, that is, PREC=PREC(y,x) and SST=SST(y,x), where y and x are indices for latitude and longitude coordinates. In Python, the code should read something like the following, given that you have &lt;code&gt;PREC&lt;/code&gt;, &lt;code&gt;SST&lt;/code&gt; fields and the &lt;code&gt;lat&lt;/code&gt; and &lt;code&gt;lon&lt;/code&gt; arrays of coordinates as Numpy arrays.&lt;/p&gt;&#xA;&#xA;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;import numpy as np&#xA;&#xA;# Initialize variable with shape of PREC, filled with missing values:&#xA;PRECL = np.zeros(np.shape(PREC))&#xA;PRECL.fill(np.nan)&#xA;&#xA;# Check the content of each cell in SST, to decide about PRECL:&#xA;for x in range(len(lon)):&#xA;    for y in range(len(lat)):&#xA;        if np.isnan(SST[y,x]):&#xA;            PRECL[y,x] = PREC[y,x]&#xA;        else:&#xA;            PRECL[y,x] = np.nan&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="8396" LastEditorUserId="8396" LastEditDate="2019-05-07T14:01:45.137" LastActivityDate="2019-05-07T14:01:45.137" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16895" PostTypeId="1" AcceptedAnswerId="16919" CreationDate="2019-05-07T14:08:02.600" Score="1" ViewCount="163" Body="&lt;p&gt;I miss the definition of &lt;strong&gt;ammonite&lt;/strong&gt;. In my opinion, many authors confuse the term &quot;&lt;strong&gt;Ammonite&lt;/strong&gt;&quot; and &quot;Ammonoid&quot;. Ammonoids (Ammonoidea) are large group of cephalopods including for example goniatites (Goniatitida), ceratites (Ceratitida) and &lt;strong&gt;ammonites&lt;/strong&gt; (&lt;strong&gt;Ammonitida?&lt;/strong&gt;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: If you think that ammonites and ammonoids are the same, you are not right. Notice that researchers try to avoid using the term ammonite when talking about paleozoic ammonoids. Ammonites are usually refered to jurassic and cretaceous ammonoids. &#xA;&quot;While goniatites proliferated during the Carboniferous, ammonites thrived in Mesozoic times.&quot;&#xA;&lt;a href=&quot;https://www.researchgate.net/publication/262048294_Goniatites&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/publication/262048294_Goniatites&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But how can we strictly define &quot;&lt;em&gt;true ammonite&lt;/em&gt;&quot;? Is it because of the ammonitic suture? This way, many triassic, jurassic, creataceous and possibly paleogenic (danian) ammonoids could be called true ammonites, because they have complex (ammonitic) sutures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can we call all jurassic and cretaceous ammonoids (phylloceratina, psiloceratina, lytoceratina, ammonitina, haploceratina, perisphinctina and ancyloceratina) &lt;strong&gt;ammonites&lt;/strong&gt;? Can you show me where ammonites are on phylogenetic tree?&lt;/p&gt;&#xA;" OwnerUserId="7031" LastEditorUserId="2958" LastEditDate="2019-12-01T20:19:23.807" LastActivityDate="2019-12-01T20:19:23.807" Title="What exactly is ammonite?" Tags="|fossils|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16897" PostTypeId="2" ParentId="16876" CreationDate="2019-05-07T16:23:01.087" Score="1" Body="&lt;p&gt;The land-sea mask for ERA Interim is available &lt;a href=&quot;https://apps.ecmwf.int/datasets/data/interim-full-invariant/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="13524" LastActivityDate="2019-05-07T16:23:01.087" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16898" PostTypeId="2" ParentId="16588" CreationDate="2019-05-07T16:33:00.930" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Any Python/R packages that can extract and plot these data in an efficient way?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I can highly recommend using the Python package &lt;a href=&quot;http://xarray.pydata.org/en/stable/&quot; rel=&quot;nofollow noreferrer&quot;&gt;xarray&lt;/a&gt; or &lt;a href=&quot;https://scitools.org.uk/iris/docs/latest/&quot; rel=&quot;nofollow noreferrer&quot;&gt;iris&lt;/a&gt; for data analysis and &lt;a href=&quot;https://scitools.org.uk/cartopy/docs/latest/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cartopy&lt;/a&gt; for plotting. &lt;/p&gt;&#xA;" OwnerUserId="13524" LastEditorUserId="13524" LastEditDate="2019-09-10T08:41:47.307" LastActivityDate="2019-09-10T08:41:47.307" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16899" PostTypeId="1" CreationDate="2019-05-07T20:35:39.610" Score="3" ViewCount="324" Body="&lt;p&gt;I'm working on a programming project in which I want to show isobars on a map with OpenStreetMap and the HTML tag &lt;em&gt;canvas&lt;/em&gt;. The main problem that I'm facing is the dificulty of retrieving consistent data to draw the isobars and, therefor, calculate wind speed and direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I gave up trying to find real time data, and also I'm starting to doing so about getting open sea data (atmospheric pressure and temperature data in open sea, the first idea I had). So, right now, I'm searching for a platform where I can retrieve this kind of data in Europe (Spain in particular would be very nice) so I can start working on drawing isobars and calculating wind variables. I looking for measurements with some density (for example, 200 or 300 points of measurement across Spain within 4 times in a day) to draw the isobars.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The best (and kind of only) way to do so would be in JSON, because it would be quite easy to manipulate and work with the data, but also plain text would work.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks to anyone who answers me.&lt;/p&gt;&#xA;" OwnerUserId="16833" LastActivityDate="2019-06-08T16:03:15.417" Title="Get atmospheric pressure values through JavaScript" Tags="|meteorology|atmosphere|climate|open-data|data-formats|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16902" PostTypeId="2" ParentId="16892" CreationDate="2019-05-08T06:56:42.427" Score="1" Body="&lt;p&gt;I would recommend changing from ERA-Interim to ERA-5, since ERA-Interim will be outdated soon. This is the information currently given by the data provider:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;ERA Interim is being phased out. Users are strongly advised to migrate to ERA5. The last date to be made available in ERA Interim will be 31 August 2019, which will be released at the end of October 2019.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It would still be good to solve the issue you are currently having with ERA-Interim. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;[...] some grid cells over land have sea-ice information. Not a big issue so far, because spatial discretization must always lead to some discrepancy in land-sea mask. [...]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As you mention, spatial discretization can lead to discrepancies. Do you use the land-sea mask from the &lt;a href=&quot;https://apps.ecmwf.int/datasets/data/interim-full-invariant/&quot; rel=&quot;nofollow noreferrer&quot;&gt;data provider&lt;/a&gt;? If the land-sea mask is given in a fraction, you would have the possibility to put a threshold on the land-sea fraction and thereby filtering out &quot;coastal&quot; gridpoints. The best value for this threshold depends on your application.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;[...] But these specific grid cells, those closest to the coast (or even on land) show very weird values sometimes. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Is the dataset conforming to the &lt;a href=&quot;http://cfconventions.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CF conventions&lt;/a&gt;? If so, the variable considered most likely has a valid_range attribute. There are specific rules specified how software should treat the data. You should check that your software adheres to these rules. Inspecting the data with another software package can be helpful. If this does not solve the problem, I suggest contacting the data provider, since there might be a real issue with the data that they should be aware of.&lt;/p&gt;&#xA;" OwnerUserId="13524" LastEditorUserId="13524" LastEditDate="2019-05-08T08:43:42.087" LastActivityDate="2019-05-08T08:43:42.087" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16903" PostTypeId="1" AcceptedAnswerId="16904" CreationDate="2019-05-08T07:16:53.340" Score="0" ViewCount="147" Body="&lt;p&gt;The more carbon dioxide in the atmosphere the more global warming. The more global warming the more cloud formations that cool the earth and clean the air from carbon dioxid when rain- and snowfall, in a very longtime perspective. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sooner or later the cloud formations will reach a point of equilibrium when global warming cease in a state of much more clouds, much more and stronger storms. When global cooling and decrease of carbon dioxide, the glaciation will increase the albedo and support the global cooling with amplifying feedback, as atmospheric carbon dioxid support global warming with amplifying feedback.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This seems to be in accordance with the historical peaks of temperature anomalies and carbon dioxide rates. The question is, does this mechanism works in the industrial era? Will the storms, if necessary, stop the extra  emissions of carbon dioxide? If human being isn't able to cut it down?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;I can't change the question as that may make answers inadequate, but I will formulate your criticism under the line, eventually.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Simulations doesn't attests that clouds in general have a netto cooling effect.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Rain and snow doesn't transport a significant amount of &lt;span class=&quot;math-container&quot;&gt;$\mathbf{CO_2}$&lt;/span&gt; from the atmosphere to the ground in a short term perspective.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The prediction doesn't refer to the equilibrium &#xA;&lt;span class=&quot;math-container&quot;&gt;$\mathbf{CO_2+H_2O}\rightleftharpoons\mathbf{H_2CO_3}$&lt;/span&gt; in the oceans.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The prediction doesn't refer to the effect of &lt;span class=&quot;math-container&quot;&gt;$\mathbf{CO_2}$&lt;/span&gt; on formation of clouds or it's influence of the cooling effect of clouds.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The prediction doesn't refer to water vapor as a greenhouse gas and that clouds are condensed vapor.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The prediction doesn't refer to different types of clouds.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="16809" LastEditorUserId="16809" LastEditDate="2019-05-09T15:36:31.193" LastActivityDate="2019-05-09T15:36:31.193" Title="How to improve this prediction about the climate in future?" Tags="|meteorology|climatology|human-influence|glaciation|global-weirding|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16904" PostTypeId="2" ParentId="16903" CreationDate="2019-05-08T11:44:38.187" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The more carbon dioxide in the atmosphere the more global warming. The more global warming the more cloud formations that cool the earth [...]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The effect of clouds on global warming is highly uncertain. The &lt;a href=&quot;https://www.ipcc.ch/report/ar5/wg1/&quot; rel=&quot;nofollow noreferrer&quot;&gt;5th IPCC report&lt;/a&gt; states the following in this regard:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The sign of the net radiative feedback due to all cloud types is less certain but likely positive. Uncertainty in the sign and magnitude of the cloud feedback is due primarily to continuing uncertainty in the impact of warming on low clouds.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Your statement continues:  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;[...] and clean the air from carbon dioxid when rain- and snowfall.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is a wrong or misleading statement. Although given that CO2 dissolves in water, for sure some CO2 is washed out with every rain shower, this does not significantly affect the total amount of CO2 in the atmosphere. This is also reflected in the relatively long residence time of CO2 in the atmosphere. This &lt;a href=&quot;https://www.theguardian.com/environment/2012/jan/16/greenhouse-gases-remain-air&quot; rel=&quot;nofollow noreferrer&quot;&gt;Guardian article&lt;/a&gt; states it as follows:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The lifetime in the air of CO2, the most significant man-made greenhouse gas, is probably the most difficult to determine, because there are several processes that remove carbon dioxide from the atmosphere. Between 65% and 80% of CO2 released into the air dissolves into the ocean over a period of 20–200 years. The rest is removed by slower processes that take up to several hundreds of thousands of years, including chemical weathering and rock formation. This means that once in the atmosphere, carbon dioxide can continue to affect climate for thousands of years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I think you need to significantly reformulate your original post, starting by taking out the false statements.&lt;/p&gt;&#xA;" OwnerUserId="13524" LastActivityDate="2019-05-08T11:44:38.187" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="16907" PostTypeId="1" CreationDate="2019-05-08T22:17:56.943" Score="3" ViewCount="144" Body="&lt;p&gt;&lt;strong&gt;What physical parameters determine the scale of columnar jointing?&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;What makes the columns thinner or thicker? &lt;/li&gt;&#xA;&lt;li&gt;What makes them taller or shorter? &lt;/li&gt;&#xA;&lt;li&gt;What causes the variation in a given site? &lt;/li&gt;&#xA;&lt;li&gt;What makes the polygons more/less regular? &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I'm guessing factors include internal temperature, cooling timescales, composition, etc, but the literature seems to be a little uncertain. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Related questions and answers on StackExchange emphasize the formation processes, but they do not directly address the scaling:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/4881/what-processes-produced-the-basalt-columns-of-the-giants-causeway&quot;&gt;What processes produced the basalt columns of the Giant&amp;#39;s Causeway?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/7981/basalt-vs-columnar-basalt&quot;&gt;Basalt vs. columnar basalt&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="4439" LastActivityDate="2019-12-16T09:44:56.613" Title="What determines the scale of columnar jointing?" Tags="|volcanology|petrology|geomorphology|igneous|" AnswerCount="1" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16908" PostTypeId="1" AcceptedAnswerId="16922" CreationDate="2019-05-09T08:48:10.153" Score="1" ViewCount="71" Body="&lt;p&gt;Being given that decaying corpses will stop emitting digestive metane, but would release huge amount of methane during their decaying process, I was wondering if this could be considered among the &lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_change_feedback&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate change feedback loops&lt;/a&gt;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To illustrate this, let's just say that scenarii for year 2050 include possibility that population (and livestock) would collapse in a decade. We may have something like 200'000'000 tons mammals decaying in a 5-10 years span... This is not even a quarter on below image, but already so many methane released at once!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit&lt;/strong&gt;: I am not looking for existing signs, I am thinking of the effect of billions of mammals death on the greenhouse effect caused by the consequent huge methane release.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QmLij.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QmLij.png&quot; alt=&quot;Land Mammals by weigth&quot;&gt;&lt;/a&gt;&#xA;(copied from &lt;a href=&quot;https://media.treehugger.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://media.treehugger.com&lt;/a&gt;, credits XKCD) &lt;/p&gt;&#xA;" OwnerUserId="15622" LastEditorUserId="15622" LastEditDate="2019-05-10T07:49:11.943" LastActivityDate="2019-05-10T18:25:30.693" Title="What would be the extent of the feedback on climate of unattended deaths event?" Tags="|climate-change|carbon-cycle|methane|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16909" PostTypeId="1" CreationDate="2019-05-09T11:41:05.713" Score="1" ViewCount="239" Body="&lt;p&gt;I came across the barotropic vorticity equation (below) in &lt;a href=&quot;https://doi.org/10.1080/03091920290020977&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sakamoto (2002)&lt;/a&gt; and I cannot figure it out. The notation is not clear to me. How can it be derived from the Navier-Stokes equation?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HyaHJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HyaHJ.png&quot; alt=&quot;excerpt from paper&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ \beta\psi_x=\frac{\tau_x^y-\tau_y^x}{\rho_0H}-r\zeta+A_H\nabla^2\zeta-\frac{f_0}{H}w_D $$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\psi$&lt;/span&gt; is the streamfunction&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\nabla$&lt;/span&gt; is the horizontal gradient operator&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\zeta=\nabla^2\psi$&lt;/span&gt; is the vertical component of relative vorticity&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$(\tau_x,\tau_y)$&lt;/span&gt; is the zonal wind stress&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$f=f_0+\beta y$&lt;/span&gt; is the Coriolis parameter&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\rho_0$&lt;/span&gt; is the mean density&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$H$&lt;/span&gt; is the depth of the model ocean&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; is the inverse time scale for vorticity decay by bottom friction &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$A_H$&lt;/span&gt; is a horizontal eddy viscosity&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$w_D$&lt;/span&gt; is not explained in this paper.&lt;/p&gt;&#xA;" OwnerUserId="16846" LastEditorUserId="28050" LastEditDate="2019-05-13T22:02:36.440" LastActivityDate="2019-05-13T22:02:36.440" Title="Barotropic vorticity equation" Tags="|geophysics|fluid-dynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16910" PostTypeId="1" AcceptedAnswerId="16912" CreationDate="2019-05-09T15:25:28.787" Score="3" ViewCount="154" Body="&lt;p&gt;A friend recommended I watch this Chinese language video &lt;a href=&quot;https://www.youtube.com/watch?v=Tpws4xLMK7Y&quot; rel=&quot;nofollow noreferrer&quot;&gt;航拍西藏 2018&lt;/a&gt; (&lt;em&gt;Aerial photography in Tibet&lt;/em&gt;) and the HD drone video of scenery is stunning. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;After about 37 minutes into the video, there are shots of these tall 3D structures that I don't understand at all. The shapes look familliar and remind me of something I think I saw in California, perhaps the &lt;a href=&quot;https://en.wikipedia.org/wiki/Anza-Borrego_Desert_State_Park&quot; rel=&quot;nofollow noreferrer&quot;&gt;Anza-Borrego desert&lt;/a&gt; in California, but it was nothing like this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm told that the area is called 札达土林 in Chinese, and that seems to be &lt;a href=&quot;https://en.wikipedia.org/wiki/Zanda_County&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zanda County in Tibet&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;update:&lt;/strong&gt; See for example 31.5230N, 79.6900E and &lt;a href=&quot;https://chinese.stackexchange.com/a/33884/18487&quot;&gt;this answer&lt;/a&gt; which recommends the name &lt;a href=&quot;https://www.tripadvisor.com.br/Attraction_Review-g1136581-d1871496-Reviews-Zhada_Earth_Forest_National_Geopark-Zanda_County_Tibet.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zhada Earth Forest National Geopark&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is it exactly that produces these amazing 3D layered and ridged structures in China, and what are they called?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ifmn2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ifmn2.jpg&quot; alt=&quot;札达土林 Zanda County in Tibet&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pzPvL.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pzPvL.jpg&quot; alt=&quot;札达土林 Zanda County in Tibet&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2019-08-28T21:00:36.650" LastActivityDate="2019-08-28T21:00:36.650" Title="What produces these amazing 3D structures in Tibet?" Tags="|erosion|geologic-layers|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16911" PostTypeId="2" ParentId="16899" CreationDate="2019-05-09T15:55:04.083" Score="2" Body="&lt;p&gt;There are some problems with your request, and maybe some misunderstandings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Misunderstanding&lt;/strong&gt;: You actually need more than pressure to get wind vectors. Wind speed is nonlinear, and is dependent on more than just wind. Even if you had observations of pressure, that will only tell you how the wind is changing due to the pressure gradient force, and not due to things like transport, diffusion, or Coriolis force, especially at the resolution you are requesting. Fortunately, wind observations are much easier to get than pressure observations, so that lies in your favor. You could use satellite data to get wind data, or near the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Problem&lt;/strong&gt;: Observations aren't really on a structured grid (unless you are working with satellite data, which has quality problems), nor are they available at the resolution you want. You may be able to use model data or reanalysis data, but even the resolutions you request may not be sufficient.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can interpolate down to whatever resolution you want.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want near realtime model data for Europe, try the &lt;a href=&quot;https://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/&quot; rel=&quot;nofollow noreferrer&quot;&gt;GFS model&lt;/a&gt; from the WPC. You can try to get data from the &lt;a href=&quot;https://www.ecmwf.int/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ECMWF&lt;/a&gt; (perhaps they have data sources I am unaware of), but their data is proprietary. You may also want to use a grib reader to access the data. If you are familiar with Python, you can use &lt;a href=&quot;https://github.com/jswhit/pygrib&quot; rel=&quot;nofollow noreferrer&quot;&gt;pygrib&lt;/a&gt;. Or you can refer to the &lt;a href=&quot;https://confluence.ecmwf.int/display/CKB/How+to+read+or+decode+a+GRIB+file&quot; rel=&quot;nofollow noreferrer&quot;&gt;ECMWF recommendations&lt;/a&gt; on reading grib files. I'm a little unfamiliar with satellite-derived products, so I can't really help you there.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2019-05-09T15:55:04.083" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16912" PostTypeId="2" ParentId="16910" CreationDate="2019-05-09T16:28:39.563" Score="3" Body="&lt;p&gt;The terrain examples show some striking similarities to what is referred to in the United States as &lt;a href=&quot;https://en.wikipedia.org/wiki/Badlands&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;Badlands&quot;&lt;/a&gt; - a type of terrain &lt;a href=&quot;https://serc.carleton.edu/research_education/nativelands/pineridge/geology2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;formed by layered sedimentary strata of rock that is soft enough to be eroded by wind and water&lt;/a&gt; into recognizably similar features. For example, here is &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Badlands00503.JPG&quot; rel=&quot;nofollow noreferrer&quot;&gt;South Dakota Badlands National Park&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/97NFw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/97NFw.jpg&quot; alt=&quot;Badlands terrain in South Dakota&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anecdotally, I have seen similar terrain in numerous areas of the Western United States, some appearing almost identical to the examples in the question. Furthermore, as mentioned in the updated question, the terrain examples shown for Zanda County, Tibet, are also referred to as the &quot;Earth Forest&quot;; further research of this specific location indicates that it was likely formed by similar erosive processes acting on &lt;a href=&quot;https://www.tibettravel.org/tibet-travel-guide/tsaparang.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;sediment stratum [...] mainly composed by sandstone and clay&quot;&lt;/a&gt;, comparable to the processes forming the various areas of Badlands in the United States. &lt;/p&gt;&#xA;" OwnerUserId="14078" LastEditorUserId="14078" LastEditDate="2019-05-09T17:17:02.280" LastActivityDate="2019-05-09T17:17:02.280" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16913" PostTypeId="2" ParentId="16909" CreationDate="2019-05-09T16:49:54.273" Score="1" Body="&lt;p&gt;This equation is a form of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Shallow_water_equations&quot; rel=&quot;nofollow noreferrer&quot;&gt;Shallow-water equations&lt;/a&gt;, which are derived from Navier-Stokes in the incompressible limit and the vertical direction is integrated out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One then takes the equation for the vorticity (which has only one component then) from the Shallow-water equations. The vorticity is split into planetary vorticity, as is the Coriolis term with the &lt;span class=&quot;math-container&quot;&gt;$\beta$&lt;/span&gt;-sheet-approximation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally it looks like they're using a velocity streamfunction.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2019-05-09T16:49:54.273" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16914" PostTypeId="1" CreationDate="2019-04-29T09:59:03.393" Score="3" ViewCount="61" Body="&lt;p&gt;The deep-sea temperature was &lt;span class=&quot;math-container&quot;&gt;$12º$&lt;/span&gt;C higher &lt;span class=&quot;math-container&quot;&gt;$50$&lt;/span&gt; My ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to know how much the atmospheric pressure at sea level had decreased and how much the water-vapour changed.&lt;br&gt;&#xA;One can consider no ice-sheets and that the sea surface temperature varyed by the same amount and that by now there is &lt;span class=&quot;math-container&quot;&gt;$0$&lt;/span&gt;% of water vapor in the atmosphere (in fact it is between 0% and 4% function of latitude and altitude and assume the conservation of atmospheric masses of &lt;span class=&quot;math-container&quot;&gt;$O_2, N_2$&lt;/span&gt;).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit add:&lt;br&gt;&#xA;This issue is very important because in this paper:&lt;br&gt;&#xA;&lt;a href=&quot;https://science.sciencemag.org/content/362/6419/eaat1327&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;Temperature-dependent hypoxia explains biogeography and severity of end-Permian marine mass extinction&quot;&lt;/a&gt; is established a link between an increase of the global temperature by 10ºC and the Great Dying global extinction via a global hypoxia.&#xA;The solubility of O2 in water is function of the temperature, &lt;strong&gt;atmospheric pressure&lt;/strong&gt; and salinity and the paper only mentions the temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT ADD&lt;br&gt;&#xA;This is a call to moderators to return this question to the PSE site where it was originally formulated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This question is specifically formulated in the field of thermodynamics with matter subject to a gravitational field and the most appropriate site to get a correct answer is the PSE as the numbers clearly show:&#xA;On the Physics website (PSE) there are 8,489 active issues marked with Thermodynamics and in this EarthScience site there are only 122 questions.&#xA; &#xA;I will offer a bounty of 500 points as a reward for the first correct answer after it is returned to the correct site.&lt;/p&gt;&#xA;" OwnerUserId="2613" OwnerDisplayName="Helder Velez" LastEditorUserId="2613" LastEditDate="2019-05-13T17:49:06.210" LastActivityDate="2019-05-13T17:49:06.210" Title="How much increase in the atmospheric pressure when the global temperature is elevated by 12 C?" Tags="|thermodynamics|pressure|temperature|" AnswerCount="0" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="16916" PostTypeId="2" ParentId="5082" CreationDate="2019-05-10T01:27:57.777" Score="0" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The approaches, based on the negative binomial model for the&#xA;  distribution of duration of the wet periods measured in days, are&#xA;  proposed to the definition of extreme precipitation. This model&#xA;  demonstrates excellent fit with real data and provides a theoretical&#xA;  base for the determination of asymptotic approximations to the&#xA;  distributions of the maximum daily precipitation volume within a wet&#xA;  period as well as the total precipitation volume over a wet period.&#xA;  The first approach to the definition (and determination) of extreme&#xA;  precipitation is based on the tempered Snedecor–Fisher distribution of&#xA;  the maximum daily precipitation. According to this approach, a daily&#xA;  precipitation volume is considered to be extreme, if it exceeds a&#xA;  certain (pre-defined) quantile of the tempered Snedecor–Fisher&#xA;  distribution. The second approach is based on that the total&#xA;  precipitation volume for a wet period has the gamma distribution.&#xA;  Hence, the hypothesis that the total precipitation volume during a&#xA;  certain wet period is extremely large can be formulated as the&#xA;  homogeneity hypothesis of a sample from the gamma distribution. Two&#xA;  equivalent tests are proposed for testing this hypothesis. Both of&#xA;  these tests deal with the relative contribution of the total&#xA;  precipitation volume for a wet period to the considered set (sample)&#xA;  of successive wet periods. Within the second approach it is possible&#xA;  to introduce the notions of relatively and absolutely extreme&#xA;  precipitation volumes. The results of the application of these tests&#xA;  to real data are presented yielding the conclusion that the intensity&#xA;  of wet periods with extreme large precipitation volume increases.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://docsbay.net/statistical-tests-for-extreme-precipitation-volumes&quot; rel=&quot;nofollow noreferrer&quot;&gt;Statistical tests for extreme precipitation volumes&lt;/a&gt; by &lt;em&gt;V. Yu. Korolev1, A. K. Gorshenin2&#xA;, K. P. Belyaev3, 29 Nov 2018&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="16829" LastActivityDate="2019-05-10T01:27:57.777" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16917" PostTypeId="1" CreationDate="2019-05-10T02:19:29.127" Score="1" ViewCount="123" Body="&lt;p&gt;I have a query regarding the practical applicability of variable separable method. Usually we decompose the variables w.r.t components corresponding to different dimensions, this method is used to solve a differential equation analytically. When it comes to the practical usage, we are often provided already with the solution in form of model output. Is it possible to decompose them along their dimensions? For example I can write the zonal velocity as&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;              U(x, y, z, t) = uv(z) * uh(x,  y,  t)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Will this decomposition be unique? I am clueless because it just seems to be a matrix multiplication. I wonder how would be the form of those matrices. Is it possible to obtain uv and uh from the data variable using any software tool?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt; An example of such a decomposition is provided &lt;a href=&quot;https://www.researchgate.net/publication/268301695_Reconsidering_the_role_of_Rossby_waves_in_the_Madden-Julian_Oscillation&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; at page number 7 (equation 2.6). I wonder if it is possible to obtain the decomposed RHS values practically from a variable.&lt;/p&gt;&#xA;&lt;p&gt;Moreover I often see a PDE associated with the decomposition which is absolutely logical. The equation is solved analytically by substituting the decomposed variables and different software tools are able to plot the analytical solution. The situation is little different in the study attached herewith. I wonder how to obtain the decomposed values if I am not getting any way to solve it analytically.&lt;/p&gt;&#xA;" OwnerUserId="11162" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-11-07T16:02:50.370" Title="Decomposition of variables in horizontal and vertical modes" Tags="|meteorology|data-analysis|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16918" PostTypeId="1" CreationDate="2019-05-10T09:17:58.590" Score="1" ViewCount="18" Body="&lt;p&gt;Is this due to increased salinity reducing sulfate concentration or the production of marsh gas converting sulfate to hydrogen sulfide or something else?&lt;/p&gt;&#xA;" OwnerUserId="16852" LastActivityDate="2019-05-10T09:17:58.590" Title="Why is sulfate reduction less important in freshwater sediments?" Tags="|geochemistry|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16919" PostTypeId="2" ParentId="16895" CreationDate="2019-05-10T09:41:31.540" Score="1" Body="&lt;p&gt;&lt;strong&gt;There is no strict definition of ammonites&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ammonites are not strictly defined. One can reffer to ammonites as to the whole group of ammonoids (Ammonoidea, ammonites sensu latto). This is common, but not supported by most researchers. Researchers use the term &quot;ammonoid&quot; for paleozoic ammonoidea and &quot;ammonite&quot; for Jurassic and Cretaceous Ammonoidea (ammonites sensu stricto). Ammonites sensu stricto reffer to ammonoids with complex (ammonitic) sutures, which are typical for Jurassic and Cretaceous ages. However, complex ammonitic sutures are not exclusive for Jurassic and Cretaceous ammonoids. Ceratitic sutures are not exclusive for Triassic either and occur in Jurassic ammonoids, too.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;So caution must be exercised when using suture lines as a means of classification. To obviate some of the problems posed by this&#xA;  simplistic classification, Wedekind, in 1918, introduced the terms&#xA;  palaeo-, meso- and neoammo-noids to classify ammonoids better.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(PDF) Goniatites. Available from: &lt;a href=&quot;https://www.researchgate.net/publication/262048294_Goniatites&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/publication/262048294_Goniatites&lt;/a&gt; [accessed May 10 2019].&lt;/p&gt;&#xA;" OwnerUserId="7031" LastEditorUserId="7031" LastEditDate="2019-05-10T21:48:31.687" LastActivityDate="2019-05-10T21:48:31.687" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16920" PostTypeId="2" ParentId="2393" CreationDate="2019-05-10T11:00:15.720" Score="4" Body="&lt;p&gt;I do agree with Gimelist how gold is accumulated through hydrothermal fluids, adding that the main driver is for this process is volcanism.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is, however, something interesting to be noted. We can find very 'old' gold of the Archean, more than 2 billion years ago, and mainly during 2 periods of the Archean, mainly hydrothermal gold in very old greenstone belts of the type described by Gimelist. Think of Canada, South Africa and Australia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, there is also very 'young' gold, Tertiary/Quaternary, in the Andes, Rockies, and Philipines, Papua New Guinea and Indonesia. Those are along the 'ring of fire', and it seems you need, at least nowadays, subduction of an oceanic, and maybe old, crust, to form strong volcanism that creates the hydrothermal processes described by Gimelist.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is some gold during a few other periods, one around the formation of Pangea. That is the gold we find for instance in Spain. But worldwide it is much less than the other 2 periods, the ones from the Archean and the Tertiary/Quaternary one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is at least very interesting that we find mainly gold from mainly 2 periods, old and young, and that there is substantially less found in rocks from other era's.&lt;/p&gt;&#xA;" OwnerUserId="16854" LastEditorUserId="16854" LastEditDate="2019-05-10T12:55:24.670" LastActivityDate="2019-05-10T12:55:24.670" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16921" PostTypeId="1" AcceptedAnswerId="16935" CreationDate="2019-05-10T17:51:36.950" Score="1" ViewCount="1609" Body="&lt;p&gt;Given a rate of precipitation (in mm&lt;sup&gt;3&lt;/sup&gt;/hour), and average droplet diameter, is is it possible to calculate (or even ballpark) the density of the air+rain droplets at time of rainfall?&lt;/p&gt;&#xA;&lt;p&gt;What I mean is, if I were to take a random metric cube of rain + air during rainfall, how much would it weigh?&lt;/p&gt;&#xA;" OwnerUserId="16856" LastEditorUserId="17546" LastEditDate="2020-08-04T07:28:59.390" LastActivityDate="2020-08-04T07:28:59.390" Title="Is there a way to approximate the density of air during rain?" Tags="|precipitation|rainfall|rain|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16922" PostTypeId="2" ParentId="16908" CreationDate="2019-05-10T18:11:53.730" Score="2" Body="&lt;p&gt;Mass of Earth's atmosphere: &lt;span class=&quot;math-container&quot;&gt;$5 \times 10^{18} kg$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Concentration of methane in Earth's atmosphere: &lt;span class=&quot;math-container&quot;&gt;$1866 ppb$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mass of methane in Earth's atmosphere, present day: &lt;span class=&quot;math-container&quot;&gt;$9.3 \times 10^{12} kg$&lt;/span&gt; = 9,300,000,000 tons&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If all those dead mammals were &lt;em&gt;composed entirely of methane&lt;/em&gt;, they would increase the atmospheric concentration of methane by about 2%. They aren't, and (as @trond hansen commented) most of their carbon would be converted to &lt;span class=&quot;math-container&quot;&gt;$\ce{CO_2}$&lt;/span&gt; with a 30-fold smaller global warming footprint.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, I think it's safe to say the impact of decomposing &lt;em&gt;mammals&lt;/em&gt; would be relatively small.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Worry more about effects on &lt;em&gt;plants&lt;/em&gt;, which constitute 80% of the Earth's biomass; bacteria, which constitute 15%; and fungi, which constitute about 2%. The entire animal kingdom amounts to much less than half a percent of global biomass, and half of &lt;em&gt;that&lt;/em&gt; is arthropods (which have their own concerns for the future).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Source: &lt;a href=&quot;https://www.pnas.org/content/115/25/6506/tab-figures-data&quot; rel=&quot;nofollow noreferrer&quot;&gt;figures from&lt;/a&gt; &lt;em&gt;The biomass distribution on Earth&lt;/em&gt;, Yinon M. Bar-On, Rob Phillips, and Ron Milo, PNAS June 19, 2018 115 (25) 6506-6511; first published May 21, 2018 &lt;a href=&quot;https://doi.org/10.1073/pnas.1711842115&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1073/pnas.1711842115&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="13324" LastEditorUserId="13324" LastEditDate="2019-05-10T18:25:30.693" LastActivityDate="2019-05-10T18:25:30.693" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16924" PostTypeId="2" ParentId="16921" CreationDate="2019-05-10T20:46:46.893" Score="1" Body="&lt;p&gt;You could calculate the mass of the water per cubic meter of air during rain by dividing the precipitation rate (in kg/m2/s) through the fall velocity (m/s) of the droplets. Or alternatively, from multiplying average droplet mass (volume x water density) with their number concentration. &lt;/p&gt;&#xA;" OwnerUserId="13524" LastActivityDate="2019-05-10T20:46:46.893" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16927" PostTypeId="2" ParentId="16917" CreationDate="2019-05-11T08:47:23.160" Score="1" Body="&lt;p&gt;Multiplicative decomposition as defined in the post is often called &lt;em&gt;factorization&lt;/em&gt;. It is not always possible to achieve an exact factorization. There would be some residual difference that we could denote as &lt;code&gt;eps(x, y, z, t)&lt;/code&gt;.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;U(x, y, z, t) = uv(z) * uh(x,  y,  t) + eps(x, y, z, t)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Such a decomposition is not unique, however you may choose a pair of functions that minimizes the value of &lt;code&gt;eps(x, y, z, t)&lt;/code&gt; according to some metric.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For further reading consider the description of sklearn &lt;a href=&quot;https://scikit-learn.org/stable/modules/generated/sklearn.decomposition.NMF.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Non-negative matrix factorization function&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2511" LastActivityDate="2019-05-11T08:47:23.160" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16933" PostTypeId="1" CreationDate="2019-05-11T21:56:46.917" Score="1" ViewCount="86" Body="&lt;p&gt;So just having issues with identification looks like a outer line of rock  a bit transparent but the inside polished looks waxy other side of stone a bit more foggy but still blue visible&lt;img src=&quot;https://i.stack.imgur.com/46AlM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1pnaj.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Edit - extra info from OP supplied in a comment, added here&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rough on the edge like stone and scratched just now with dime no real damage just a mark of the dime being dragged on the surface. Found this when I moved in to house previous owner left it he was Vietnamese. Inside looks like minerals form edge moving up toward center&lt;/p&gt;&#xA;" OwnerUserId="16863" LastEditorUserId="28050" LastEditDate="2019-05-13T21:53:55.940" LastActivityDate="2019-05-13T21:53:55.940" Title="Is this a geode?" Tags="|geology|" AnswerCount="0" CommentCount="1" ClosedDate="2021-05-16T12:57:09.033" ContentLicense="CC BY-SA 4.0" />
  <row Id="16935" PostTypeId="2" ParentId="16921" CreationDate="2019-05-12T04:47:16.647" Score="3" Body="&lt;p&gt;Air &lt;em&gt;without&lt;/em&gt; rain has a mass of about &lt;span class=&quot;math-container&quot;&gt;$\ce{1200 g/m^3}$&lt;/span&gt; at 20°C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can figure out the amount of water in falling rain if you know the &lt;em&gt;rate of accumulation&lt;/em&gt; (how much rain falls through a given volume in a given time, landing on the ground) and the &lt;em&gt;velocity&lt;/em&gt; of the falling rain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.dmcinfo.com/latest-thinking/blog/id/206/geek-challenge-rain-drop-density&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's a link&lt;/a&gt; to a post elsewhere on this same question. In that discussion, they assume a rainfall rate of 1 inch (2.54cm) per hour, and estimate a raindrop's terminal velocity (from observation) at about 9 m/s. They divide that rate by that velocity (converting units), and come up with about &lt;span class=&quot;math-container&quot;&gt;$\ce{3/4 cm^3}$&lt;/span&gt; of water per &lt;span class=&quot;math-container&quot;&gt;$\ce{m^3}$&lt;/span&gt; of rain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, given those assumptions, the density of (rain + air) is about .06% higher than the density of air without rain. Interestingly, that's &lt;em&gt;much less&lt;/em&gt; than the difference in density between dry and humidity-saturated air (about 1% at 20°C). In other words, air at 100% relative humidity with heavy rain falling through it is &lt;em&gt;still&lt;/em&gt; less dense than dry air.&lt;/p&gt;&#xA;" OwnerUserId="13324" LastActivityDate="2019-05-12T04:47:16.647" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16937" PostTypeId="1" CreationDate="2019-05-12T09:53:26.237" Score="3" ViewCount="62" Body="&lt;p&gt;Earth revolves around the Sun in a elliptical path, situated on one of the Sun's focal points. If Earth is considered as a large body with mass attracted towards the Sun's core causing its revolution and rotation, what is the reason behind an angle of inclination of 23°30' that Earth makes with the plane of solar system? Theoretically, if Sun's gravitational pull drives Earth into revolution and spin, then the rotational axis should be perpendicular to plane of the solar system.&lt;/p&gt;&#xA;" OwnerUserId="16868" LastEditorUserId="2470" LastEditDate="2019-05-12T14:07:26.407" LastActivityDate="2019-05-17T07:05:26.157" Title="Query about inclination in Earth's axis of rotation" Tags="|earth-rotation|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="16942" PostTypeId="1" CreationDate="2019-05-12T20:23:13.107" Score="1" ViewCount="111" Body="&lt;p&gt;The past few weeks of spring in northern Ohio I believe I have noticed a weather pattern where the weather forecast will show a string of days with rain, but what happens is the day is mostly clear, then near the end of day the clouds move in, it rains for several hours, then clears out again and repeats. The timing of the cycle maybe shifts a little, but it is a pattern of hours of rain and hours of mostly clear skies that repeats. I'm used to getting thunderstorms in the spring, but this pattern isn't even producing weather that severe. &lt;/p&gt;&#xA;" OwnerUserId="16872" LastActivityDate="2019-05-12T20:23:13.107" Title="Does this weather pattern have a name?" Tags="|meteorology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16946" PostTypeId="1" CreationDate="2019-05-14T02:42:54.537" Score="1" ViewCount="88" Body="&lt;p&gt;The abstract of the new Nature Geoscience paper &lt;a href=&quot;https://www.nature.com/articles/s41561-019-0362-2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Shallow seismic activity and young thrust faults on the Moon&lt;/a&gt; reads:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;The discovery of young thrust faults on the Moon is evidence of recent tectonic activity, but how recent is unknown.&lt;/strong&gt; Seismometers at four Apollo landing sites recorded 28 shallow moonquakes between 1969 and 1977. Some of these shallow quakes could be associated with activity on the young faults. However, the epicentre locations of these quakes are poorly constrained. Here we present more-accurate estimates of the epicentre locations, based on an algorithm for sparse seismic networks. We found that the epicentres of eight near-surface quakes fall within 30 km of a fault scarp, the distance of the expected strong ground shaking. From an analysis of the timing of these eight events, we found that six occurred when the Moon was less than 15,000 km from the apogee distance. Analytical modelling of tidal forces that contribute to the current lunar stress state indicates that seven near-apogee events within 60 km of a fault scarp occur at or near the time of peak compressional stresses, when fault slip events are most likely. &lt;strong&gt;We conclude that the proximity of moonquakes to the young thrust faults together with evidence of regolith disturbance and boulder movements on and near the fault scarps strongly suggest the Moon is tectonically active.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question(s):&lt;/strong&gt; I'd like to understand &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;what young thrust faults are&lt;/li&gt;&#xA;&lt;li&gt;how one can decide that there is a fault on the Moon (apart from the &quot;evidence of regolith disturbance and boulder movements on and near the fault scarps&quot;)&lt;/li&gt;&#xA;&lt;li&gt;what one might use as evidence to classify a fault on the Moon as a &lt;em&gt;thrust fault&lt;/em&gt;&lt;/li&gt;&#xA;&lt;li&gt;how might one decide that the thrust fault is also &lt;em&gt;young&lt;/em&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The Nature Geoscience paper is paywalled, but there is some additional discussion in Phys.org's &lt;a href=&quot;https://phys.org/news/2019-05-moon-quaking.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;The moon is quaking as it shrinks&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Some background on the seismometers on the Moon:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://space.stackexchange.com/q/26502/12102&quot;&gt;Why were the “perfectly functioning” seismometers placed by Apollo 12, 14, 15 and 16 astronauts all shut off in 1977?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://space.stackexchange.com/q/21293/12102&quot;&gt;Any potential downside to throwing personal life support out the door on the Moon?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; images from &lt;a href=&quot;https://www.honeysucklecreek.net/msfn_missions/ALSEP/hl_alsep.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ALSEP, Apollo Lunar Surface Experiments Package&lt;/a&gt;, 20 November 1969 – 30 September 1977, by Hamish Lindsay, Click for full size.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/N3xd9.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/N3xd9m.jpg&quot; alt=&quot;NASA scientists Lunar data&quot;&gt;&lt;/a&gt;  &lt;a href=&quot;https://i.stack.imgur.com/tKviK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tKviKm.jpg&quot; alt=&quot;NASA Lunar seismogram&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2020-04-30T09:36:28.507" LastActivityDate="2020-04-30T09:36:28.507" Title="What are &quot;young thrust faults&quot; and how does one identify them on the Moon?" Tags="|seismology|moon|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="16948" PostTypeId="1" AcceptedAnswerId="16950" CreationDate="2019-05-14T07:30:45.903" Score="6" ViewCount="151" Body="&lt;p&gt;Here are photos from West of Normandy, at 7-9am after sunrise on the 14th of may, from &lt;a href=&quot;https://www.meteo60.fr/satellites/visible-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;the visible satellite&lt;/a&gt;. It's a bit strange that they are visible from space, they are 2-3 miles wide? Are they jet engine trails? &#xA;To see the original images you can rewrite the time on these hyperlinks to 8-15 etc...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://archives.meteo60.fr/images_sat_vis/2019/semestre1/Sat_vis_20190514-08h00.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://archives.meteo60.fr/images_sat_vis/2019/semestre1/Sat_vis_20190514-08h00.png&lt;/a&gt; &amp;lt;-hours&#xA;&lt;a href=&quot;https://i.stack.imgur.com/4ZuZz.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4ZuZz.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/SLtr7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SLtr7.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/aD7pV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aD7pV.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorDisplayName="user12525" LastEditDate="2019-08-28T08:59:04.640" LastActivityDate="2019-08-28T08:59:04.640" Title="Are these plane trails seen from satellite" Tags="|meteorology|clouds|air-pollution|weather-satellites|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16950" PostTypeId="2" ParentId="16948" CreationDate="2019-05-14T15:44:03.697" Score="6" Body="&lt;p&gt;Under the right conditions (in a basic sense, locally high relative humidity; see also &lt;a href=&quot;https://earthscience.stackexchange.com/questions/15566/how-to-predict-when-contrails-are-likely-to-form-over-a-specific-location-using/15586#15586&quot;&gt;this discussion on this site&lt;/a&gt; regarding contrail formation), the clouds initially formed by contrails &lt;a href=&quot;https://www.britannica.com/science/vapor-trail&quot; rel=&quot;nofollow noreferrer&quot;&gt;may persist for hours and spread outwards to form larger areas of cirrus cloud&lt;/a&gt;. Additionally, NASA's Contrail Education Project website has some specific examples &lt;a href=&quot;https://science-edu.larc.nasa.gov/contrail-edu/imagery.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; showing the evolution of contrails and associated clouds over the course of a day, with extremely similar visual properties to those shown in the question. They also provide some discussion describing how large these clouds must be compared to what a typical weather satellite &quot;sees&quot;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In order to be seen, a contrail must be wide enough (and long enough) to change the brightness of a satellite pixel. Each pixel covers a portion of the Earth. The size of that area is determined by the resolution of the satellite instrument. Typical weather satellites, such as you see on the news, have pixels that might be 8 km, 4 km, or 1 km on a side. To show up in such an image, a contrail must be nearly 1 km wide! &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In other words, &lt;strong&gt;yes, they are contrails (or more accurately, persistent clouds originating from contrails) as observed by satellite.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="14078" LastEditorUserId="14078" LastEditDate="2019-05-16T04:16:52.710" LastActivityDate="2019-05-16T04:16:52.710" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16952" PostTypeId="1" CreationDate="2019-05-15T12:46:31.847" Score="1" ViewCount="154" Body="&lt;p&gt;I'm stuck implementing a reverse time migration technique, the PDE(partial differential equation) being implemented is an acoustic wave equation, The numerical method being used is a FD(finite difference method) using SBP(summation by parts) property to ensure stability across the domain,i.e., this changes the coefficients that the FD use in the boundary and near boundary points, in addition to the SAT(simultaneous approximation terms) that will mimic how the continuous energy method is implemented and that would guarantee long time stability across the model. i need help with implementing the SAT for a 2D grid, each time i run the model with the SAT I've implemented it diverges at the last time-steps. IS there any well known acoustic-2D-wave equation that includes SAT to weakly enforce boundary conditions ??&lt;/p&gt;&#xA;" OwnerUserId="16886" LastActivityDate="2019-05-19T16:53:11.927" Title="reverse time migration for wave equation PDE using SBP-SAT" Tags="|seismology|waves|seismic|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16955" PostTypeId="1" AcceptedAnswerId="16978" CreationDate="2019-05-15T21:49:27.643" Score="1" ViewCount="77" Body="&lt;p&gt;Could a small meteor or natural nuclear explosion melt an ice cap on Earth to trigger a mini ice age without the event being observed by people?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can the Earth have an overlaying thermal cycle that collects heat until it triggers long global winter? &lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2019-05-19T05:15:56.177" LastActivityDate="2019-05-19T09:17:41.100" Title="How big of an event is needed to trigger a long winter?" Tags="|meteorology|atmosphere-modelling|weather-forecasting|ice-age|winter|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16959" PostTypeId="1" CreationDate="2019-05-16T14:45:44.223" Score="5" ViewCount="59" Body="&lt;p&gt;I was wondering about the common saying that on a sunny, cloud-free day, depending on location, you can get a sunburn even when spending the whole day in the shadows.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Already our blue sky provides ample evidence that there is some photon intensity  being scattered out of the direct solar irradiation path into the whole celestial half-sphere very efficiently. One can formalize this, by defining the ratio of energy in a certain waveband B coming from the sky minus the sun divided by the energy coming from the sun as&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\rm \eta_B \equiv \frac{E_{B,full sky}-E_{B,sun}}{E_{B,sun}}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, as is known, Rayleigh-scattering efficiency goes with &lt;span class=&quot;math-container&quot;&gt;$\rm 1/\lambda^4$&lt;/span&gt;. Therefore I would expect it to be in the ultraviolet &lt;span class=&quot;math-container&quot;&gt;$\rm \eta_{\rm UV} &amp;gt; \eta_{\rm Blue}$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But my question would be: What is  &lt;span class=&quot;math-container&quot;&gt;$\rm \eta_{UV}$&lt;/span&gt; exactly? And how does it depend on lat/alt/time of the day...? I bet there are measurements as well as radiative transfer computations on this, but I have zero familiarity with the Earth science literature on this, so I'm asking here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Related in astronomy: &lt;a href=&quot;https://astronomy.stackexchange.com/questions/21039/what-is-the-radiant-intensity-of-the-celestial-sphere&quot;&gt;Recent question&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="489" LastEditDate="2019-05-19T12:13:28.423" LastActivityDate="2019-05-19T12:13:28.423" Title="Amount of scattered vs. direct UV light from the Sun" Tags="|atmospheric-radiation|radiative-transfer|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16962" PostTypeId="1" AcceptedAnswerId="17010" CreationDate="2019-05-17T09:31:00.377" Score="4" ViewCount="8346" Body="&lt;p&gt;I am new with Python so please be kind. &#xA;I want to download data from ERA5 and so far I have installed the CDS API package and followed all the instructions from &lt;a href=&quot;https://cds.climate.copernicus.eu/api-how-to&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://cds.climate.copernicus.eu/api-how-to&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have my main file ready to use but I get an error about the configuration file. I know that this file should contain the following:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;url: https://cds.climate.copernicus.eu/api/v2&#xA;key: {UID}:{key}&#xA;verify:0&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;I have created a text file and a configuration file with this info and I have placed them in the following address (as required by the error I get in python):&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;C:\Users\username\.cdsapirc&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;However, I still get the same error. What I am doing wrong? Do I need to create a different type of file? Do I need to write the user info in a different way?&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Exception: Missing/incomplete configuration file: C:\Users\username/.cdsapirc&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;By the way, I'm using a windows computer.&lt;/p&gt;&#xA;" OwnerUserId="15677" LastEditorUserId="15677" LastEditDate="2019-05-20T07:42:41.460" LastActivityDate="2022-02-02T08:23:52.533" Title="Error trying to download ERA5 data: Exception: Missing/incomplete configuration file: C:\Users\username/.cdsapirc" Tags="|reanalysis|era|python|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16971" PostTypeId="1" CreationDate="2019-05-17T20:15:57.077" Score="1" ViewCount="59" Body="&lt;p&gt;I do not have a lot of knowledge in aerodynamics but I need to be able to derive turbulence strength (Cv2 and Ct2 - so called turbulence structural parameters I think) from turbulence intensity. Does anyone know how to do this?&lt;/p&gt;&#xA;" OwnerUserId="16905" LastActivityDate="2019-05-17T20:15:57.077" Title="Turbulence strength from turbulence intensity?" Tags="|turbulence|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="16972" PostTypeId="2" ParentId="16508" CreationDate="2019-05-17T21:04:48.113" Score="3" Body="&lt;p&gt;Hydrology major here, for whatever that's worth :) Some possibilities from my readings/internships:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First I'd check the gage you're using for stage--if it's moved in the last 8 years, the stage may need to be correlated to what it would be at the former site. If it hasn't, it's more likely something changed in your stretch of channel. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the channel has deepened at your location and not at wherever the gage is located, then you'll see less flooding. If the gage is upstream of your stretch of stream, I'd be suspicious of any new wetland areas that could accommodate water; if it's downstream, of any dam removal or other loss of channel restriction that could be allowing water to get past your site more quickly. Downstream changes in the channel could also affect your site! And if it's fairly urban, maybe the city has figured out ways to divert runoff farther downstream?&lt;/p&gt;&#xA;" OwnerUserId="16906" LastActivityDate="2019-05-17T21:04:48.113" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16976" PostTypeId="1" AcceptedAnswerId="17038" CreationDate="2019-05-18T12:07:38.843" Score="5" ViewCount="78" Body="&lt;p&gt;I used this tool at my degree a couple of lusters ago to do cartography with aerial &lt;a href=&quot;https://en.wikipedia.org/wiki/Orthophoto&quot; rel=&quot;noreferrer&quot;&gt;orthophotos&lt;/a&gt;. We used it on cartography and geomorphology subjets. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/91UrU.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/91UrU.png&quot; alt=&quot;stereoscope&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: &lt;a href=&quot;https://www.gumtree.com.au/s-ad/somerset/collectables/vintage-waterworth-hobart-cartographers-stereoscope/1200938399&quot; rel=&quot;noreferrer&quot;&gt;gumtree.com&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The method consists on using two consecutive but overlaped orthophotos (on east-west direction) taken from a plane, so an optical effect allows you to see the relief. Then you can delimite units with a marcker pen on a transparent film. We after transpose the cartography to a topographic map. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;My question is if this tool is still used at university and among working geologists.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-05-18T12:17:02.253" LastActivityDate="2019-05-24T14:08:15.503" Title="Is sterescope still used to do cartography with orthophotography?" Tags="|geology|geomorphology|instrumentation|cartography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16977" PostTypeId="1" AcceptedAnswerId="17215" CreationDate="2019-05-19T04:23:05.363" Score="1" ViewCount="5416" Body="&lt;p&gt;Which disposable cup between plastic and styrofoam harm the environment the most?&#xA;Which is the most unhealthy to use for the Earth for humans and animals?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6kBx0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6kBx0.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/0F2a5.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0F2a5.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="1411" LastEditDate="2019-06-14T12:38:25.563" LastActivityDate="2020-11-14T07:01:07.360" Title="Which is worse, plastic or styrofoam cups?" Tags="|atmosphere|measurements|human-influence|pollution|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="16978" PostTypeId="2" ParentId="16955" CreationDate="2019-05-19T06:49:04.560" Score="2" Body="&lt;p&gt;A small meteor/asteroid impact might trigger a nuclear winter, but it would be registered by people and it would be very unlikely to trigger an ice age unless the impact created a very large amount of dust in the atmosphere. The dust would need to stay in the atmosphere for a decade or more to trigger an ice age.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A natural nuclear explosion cannot be very large because as soon as critical mass is reached it will explode so the size of the explosion is in a way self limiting. If this happened under the world's major ice sheets it will melt a relatively large amount of ice but this would be registered by an increase in radioactivity in sea water (possibly many years after the explosion took place). So this would not trigger an ice age.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A large volcanic eruption can cool the earth for a few years but is unlikely to trigger an ice age unless it lasts for several decades, and yest again, this would be registered by people. You can take a look here to see what kind of magnitudes that have happened in our history &lt;a href=&quot;https://www.ranker.com/list/the-worst-volcanic-eruptions-in-history/drake-bird&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ranker.com/list/the-worst-volcanic-eruptions-in-history/drake-bird&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you ask about an overlaying thermal cycle (as in heating until the temperature crashes), this is very unlikely to happen unless the temperature reaches a point where a very large part of life gets eradicated, as the temperature on earth goes up the ocean can hold less and less CO2 until at one point the oceans starts to release more CO2 than it absorbs from the atmosphere. This means the heating will not trigger cooling unless life on our planet is significantly reduced.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Water can hold less dissolved gasses when the temperature goes up, so at one point aerobic life in the ocean can no longer survive due to the lack of dissolved oxygen in the water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is just about how serious it might get if we keep on going like we are now.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="2470" LastEditDate="2019-05-19T09:17:41.100" LastActivityDate="2019-05-19T09:17:41.100" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16983" PostTypeId="2" ParentId="16952" CreationDate="2019-05-19T16:53:11.927" Score="1" Body="&lt;p&gt;I have no experience with SBP-SAT methods, but you may try and go through the references in (and potentially contact the authors of) this paper &lt;a href=&quot;https://arxiv.org/pdf/1802.06123.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://arxiv.org/pdf/1802.06123.pdf&lt;/a&gt; .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Personally, I don't see a strict need for using such 'complicated' modelling methods for RTM. In the ideal case, you have deghosted (i.e., upgoing) recorded data and a smooth velocity model. Then, using standard low-order finite-difference modelling on a uniform grid should already provide fairly good results at fairly little cost. Likely, you'll achieve better results by optimizing the data &amp;amp; velocity model than improving your numerical code beyond the standards. This simple MATLAB code &lt;a href=&quot;https://csim.kaust.edu.sa/files/ErSE328.2013/LAB/WE_LABS/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://csim.kaust.edu.sa/files/ErSE328.2013/LAB/WE_LABS/index.html&lt;/a&gt; already does a brilliant job using 2nd order accuracy in time and 8th order accuracy in space, using a simple FD method.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, if you are doing state-of-the-art (academic) research or are dealing with a very atypical velocity model with an extreme dynamic range, these are interesting topics to look into, and I hope that someone may be able to help you... But I hope that my answer may help you right now.&lt;/p&gt;&#xA;" OwnerUserId="12155" LastActivityDate="2019-05-19T16:53:11.927" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16984" PostTypeId="2" ParentId="9465" CreationDate="2019-05-19T18:02:21.530" Score="1" Body="&lt;p&gt;So, I know this question was asked a long time ago. But in the spirit of Stack Exchange, I will post my answer for future users perhaps.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;The Greens functions (i.e., analytical solutions)&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The first thing to be aware of are the various solutions to the wave equations change for the (1) source type and (2) the dimension.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;The source type&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Assuming acoustic waves in a homogeneous domain, that means you are either solving:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ \frac{\partial^2 p(x,t)}{\partial t^2} = c^2(x)\left(\nabla^2 p(x,t) +f(x,t) \right)  , \tag{1}$$&lt;/span&gt;&#xA;(where &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; is pressure, &lt;span class=&quot;math-container&quot;&gt;$c$&lt;/span&gt; the compressional velocity and &lt;span class=&quot;math-container&quot;&gt;$f$&lt;/span&gt; the source function), or you are solving:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ \left\{ \begin{array}{rl} \frac{\partial p(x,t)}{\partial t} &amp;amp; =  -c^2(x)\bigg( \nabla\cdot v(x,t) + g(x,t) \bigg), \\ \frac{\partial v(x,t)}{\partial t} &amp;amp; = -\nabla p(x,t). \end{array} \right. \tag{2} $$&lt;/span&gt;&#xA;The difference between (1) and (2) is a time differentiation:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ f(x,t) = \frac{\partial}{\partial t}g(x,t). $$&lt;/span&gt;&#xA;This is an important difference in source functions!&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;The Greens function equation&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;It is standard to restate equation (1) in the following form:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ \left( \frac{1}{c^2(x)}\frac{\partial^2}{\partial t^2} - \nabla^2 \right)p(x,t) = f(x,t). \tag{3a}$$&lt;/span&gt;&#xA;Transforming this equation to the frequency domain, for which &lt;span class=&quot;math-container&quot;&gt;$\partial^2/\partial t^2 \to -\omega^2$&lt;/span&gt;, and where &lt;span class=&quot;math-container&quot;&gt;$\omega^2/c^2=k^2$&lt;/span&gt; we obtain:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ \left( -k^2 - \nabla^2 \right)p(x,\omega) = f(x,\omega), \tag{3b}$$&lt;/span&gt;&#xA;or&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ \left( k^2 + \nabla^2 \right)p(x,\omega) = -f(x,\omega), \tag{3c}$$&lt;/span&gt;&#xA;We can consult, e.g., &lt;a href=&quot;https://www3.nd.edu/~atassi/Teaching/AME%2060633/Notes/greens.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www3.nd.edu/~atassi/Teaching/AME%2060633/Notes/greens.pdf&lt;/a&gt; to find the Greens functions (for which &lt;span class=&quot;math-container&quot;&gt;$f(x,\omega)=\delta(x-x_s)$&lt;/span&gt; with &lt;span class=&quot;math-container&quot;&gt;$x_s$&lt;/span&gt; the source location).&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;The Greens functions&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;I'll just copy the results. For equations of type (1) we have the Green's functions &lt;span class=&quot;math-container&quot;&gt;$G$&lt;/span&gt;:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\begin{array}{lrl}&#xA;\text{1-D:} &amp;amp; G &amp;amp; = −\frac{i}{2k}e^{−ik\lvert x−x_s \rvert}, \\&#xA;\text{2-D:} &amp;amp; G &amp;amp; = −\frac{i}{4}H_0^{(2)}(k \lvert x−x_s \rvert),\\&#xA;\text{3-D:} &amp;amp; G &amp;amp; = \frac{1}{4\pi}\frac{e^{−ik\lvert x−x_s \rvert} }{\lvert x−x_s \rvert}.&#xA;\end{array}&#xA;$$&lt;/span&gt;&#xA;Indeed, &lt;span class=&quot;math-container&quot;&gt;$H_0^{(2)}$&lt;/span&gt; is the Hankel function, in MATLAB we simply write that with &lt;code&gt;besselh(0,2, k*r)&lt;/code&gt;.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;The MATLAB implentation&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;I made the following changes w.r.t. your code:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The frequency vector can be defined from &lt;span class=&quot;math-container&quot;&gt;$f_1\in(0,\frac{1}{\Delta t})$&lt;/span&gt; rather than how you did it, which is &lt;span class=&quot;math-container&quot;&gt;$f_2\in(-\frac{1}{2\Delta t},\frac{1}{2\Delta t})$&lt;/span&gt;. In this way, the Hankel function only receives positive frequencies. Moreover, it is exactly the order in which the FFT produces its output. I thus also removed the &lt;code&gt;fftshift&lt;/code&gt; operations.&lt;/li&gt;&#xA;&lt;li&gt;I changed the Green's function to the 2-D case, i.e., I changed &lt;code&gt;const=-1i*pi&lt;/code&gt; to &lt;code&gt;const=-1i/4&lt;/code&gt;. &lt;/li&gt;&#xA;&lt;li&gt;I changed the &lt;code&gt;nfft&lt;/code&gt;, to just using the FFT of the size of the wavelet or time vector. This made it easier to obtain results of similar amplitudes... Also, I don't divide the source function by &lt;code&gt;nfft&lt;/code&gt;, to make the results relatively independent of the chosen &lt;code&gt;dt&lt;/code&gt;.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Thus, the final code, having made only small changes compared to yours, becomes:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;clc;    clear all;&#xA;&#xA;%% Parameter Setting&#xA;vel=2000;   % velocity of medium&#xA;r=1000;     % distance at which wavefield will be observed&#xA;% the final wavelet should appear at time, t=r/vel=0.5sec&#xA;&#xA;T=1;        % Total time&#xA;dt=.0025;   % time step&#xA;f0=25;      % central freq&#xA;&#xA;%% Create Source Wavelet&#xA;N = round(T/dt);        % No of samples&#xA;t0 = 5/(sqrt(2)*pi*f0);     % Zero time shift&#xA;t = dt*(0:N-1);             % time vector&#xA;tau = t-t0+1*dt;     % time vector shifted by t0&#xA;src = (1 -2* tau.*tau * f0^2 * pi^2).*exp(-tau.^2 * pi^2 * f0^2);  % source wavelet&#xA;&#xA;%%FT of signal&#xA;fmax=1/dt; % max frequency &#xA;freq= linspace(0,fmax,N);    % Freq vector:   0 &amp;lt;= f &amp;lt;= Fmax&#xA;sw=fft(src);      % fourier transform of wavelet, S(w)&#xA;&#xA;%% 2-D Greens Function &#xA;w=2*pi*freq;&#xA;const = -1i/4;&#xA;H02 = besselh(0,2,w/vel*r);&#xA;H02(1)=0;&#xA;GF = const*H02;&#xA;&#xA;%% Calculating the Wavefield  &#xA;WF= ifft(GF.*sw);&#xA;&#xA;%% Plot&#xA;% Wavelet&#xA;subplot(2,2,1);     &#xA;plot(t,src);     title('\bf{Source wavelet}'); &#xA;xlabel('Time(sec)');    ylabel('Amplitude ')&#xA;&#xA;% Frequencies&#xA;subplot(2,2,2);   &#xA;plot(freq,abs(sw));    title('\bf{Source freq spec}');  &#xA;xlabel('Frequencies(Hz)');  ylabel('Amplitude ')&#xA;xlim([0 fmax/2])&#xA;&#xA;% Gneens Fkt&#xA;subplot(2,2,3); &#xA;plot(freq,abs(GF));   title('\bf{Green Function}'); &#xA;xlabel('Frequencies(Hz)'); ylabel('Amplitude ')&#xA;xlim([0 fmax/2])&#xA;&#xA;% Wafefield&#xA;subplot(2,2,4);      &#xA;hold on&#xA;plot(t,real(WF));    title('\bf{Trace}');   &#xA;xlabel('Time(sec)');  ylabel('Amplitude')&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Provided that the signal is sampled to the Nyquist frequency, this should give good results:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ES4um.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ES4um.png&quot; alt=&quot;Matlab figure results&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12155" LastActivityDate="2019-05-19T18:02:21.530" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16985" PostTypeId="2" ParentId="16885" CreationDate="2019-05-19T18:30:16.877" Score="1" Body="&lt;p&gt;It is impossible to to convert one recorded time-series into structural information. As you correctly note, the equation&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ v_i = \frac{z_i}{t_i}, \tag{1a}$$&lt;/span&gt;&#xA;or&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ t_i(z,v) = \frac{z_i}{v_i}, \tag{1b}$$&lt;/span&gt;&#xA;is difficult to solve when you only a know one time &lt;span class=&quot;math-container&quot;&gt;$t_i$&lt;/span&gt;. That is, choosing &lt;span class=&quot;math-container&quot;&gt;$z_i$&lt;/span&gt; to twice its value would provide twice &lt;span class=&quot;math-container&quot;&gt;$v_i$&lt;/span&gt;! If you only record time &lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt;, but try to turn it into &lt;em&gt;two&lt;/em&gt; values &lt;span class=&quot;math-container&quot;&gt;$(z_i,v_i)$&lt;/span&gt;, you have an underdetermined problem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, if you have multiple traces, you know from the theory that a flat reflector produces a hyperbolic move-out (I believe it's the following equation, but I'm not 100% certain. Don't quote me on it!):&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ t_i(x,z,v) = t_0 + \frac{x^2}{v_\text{stacking}}. \tag{3}$$&lt;/span&gt;&#xA;As you know the location &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt;, knowledge of &lt;em&gt;two&lt;/em&gt; (rather than one) traces would perfectly constrain &lt;span class=&quot;math-container&quot;&gt;$t_0$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$v_\text{stacking}$&lt;/span&gt;! Just like the slides you provide in the link, the velocity &lt;span class=&quot;math-container&quot;&gt;$v_\text{stacking}$&lt;/span&gt; is usually simply found by trying many values for the move-out correction velocity, and seeing which velocity value flattens the reflector best! From that knowledge, suddenly you can constrain also the depth, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reflection seismics deals with the situation that is described in the 5 slides preceding the slide you post. We have a &lt;em&gt;lot&lt;/em&gt; of traces, and based on the assumption of hyperbolic moveouts we can perfectly obtain the stacking velocities. The slide you post approaches the problem from the other way around: &lt;em&gt;what are the stacking velocities &lt;span class=&quot;math-container&quot;&gt;$v_\text{rms}$&lt;/span&gt; you would find if you know the depth and velocity structure already?&lt;/em&gt; This is not necessarily the method used to get structural information from your data! I think that is the cause of the confusion..!&lt;/p&gt;&#xA;" OwnerUserId="12155" LastActivityDate="2019-05-19T18:30:16.877" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16986" PostTypeId="2" ParentId="16851" CreationDate="2019-05-19T18:43:22.610" Score="1" Body="&lt;p&gt;I think there are some initial exploratory abstracts out there on the topic, e.g., &lt;a href=&quot;http://www.earthdoc.org/publication/publicationdetails/?publication=75396&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.earthdoc.org/publication/publicationdetails/?publication=75396&lt;/a&gt; . But not much yet. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My view is that that MASW (multichannel analysis of surface waves) is simply so much more robust in practice compared to FWI (full waveform inversion, which really doesn't work as spectacularly well as some papers may suggest; the method requires a LOT of iterative and hands-on work, and is furthermore extremely computationally demanding, without always giving dramatically better results compared to travel-time tomographies...)... hence, I think that MASW will remain the standard in the coming future, until FWI truly becomes a 'cheap' and 'hands-off' method, which could easily take another 15+ years, I imagine...&lt;/p&gt;&#xA;" OwnerUserId="12155" LastActivityDate="2019-05-19T18:43:22.610" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16988" PostTypeId="1" AcceptedAnswerId="17300" CreationDate="2019-05-20T01:38:51.610" Score="9" ViewCount="1255" Body="&lt;p&gt;Expansion of tafoni seems to be based on weathering (seems reasonable enough.) But &lt;strong&gt;what creates them in the first place&lt;/strong&gt;? There are a number of explanations online (Wikipedia lists eight plausible causes!) Many websites trying to give a simplified explanation simply say &quot;salt weathering&quot;, but from a brief search it's clear that salt weathering is not always the cause of tafoni [0]. They develop on a wide range of rock types, from granite to sandstone to tuffs and conglomerates, and in many situations where they'd be expected to develop they don't.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From what I can tell, they seem somewhat mysterious, and there are explanations that make sense in some cases but not every case of tafoni is well explained. Is there a widely accepted explanation for the formation of tafoni?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Picture of tafoni (Martin Sharman, Wikipedia):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FLSVN.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FLSVN.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[0] for example: page 75, Arid and Semi-Arid Geomorphology, Andrew S. Goudie&lt;/p&gt;&#xA;" OwnerUserId="16925" LastActivityDate="2021-10-24T07:09:39.413" Title="Is there a widely accepted reason for the formation of tafoni?" Tags="|geology|rocks|geomorphology|erosion|weathering|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16989" PostTypeId="1" CreationDate="2019-05-20T02:53:47.663" Score="1" ViewCount="116" Body="&lt;p&gt;Usually, I use level-3 gridded satellite data to analyze the spatial and temporal patterns of  atmospheric compositions. However, there were some data sources which only afford level 2 product.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, the NH3 total column information derived from &lt;a href=&quot;https://iasi.aeris-data.fr/nh3_iasi_a_arch/&quot; rel=&quot;nofollow noreferrer&quot;&gt;IASI&lt;/a&gt; was in level-2 format. But, I saw some paper presented the NH3 distribution very well with those data. An example here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FgnqJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FgnqJ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A simple template file was uploaded &lt;a href=&quot;https://drive.google.com/open?id=1Uv6SIDMDDcbVfquZ7vGMoJL_3qQ5yP3V&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;from netCDF4 import Dataset&#xA;fc = Dataset(&quot;./nh3nn_v2_2_20160209_AM.nc&quot;)&#xA;print fc.variables['longitude'][:].shape&#xA;print fc.variables['latitude'][:].shape&#xA;print fc.variables['column'][:].shape&#xA;&amp;gt;(633969L,)&#xA;&amp;gt;(633969L,)&#xA;&amp;gt;(633969L,)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;For now, I can't find the specific pattern of the orbit. Is there any simple method to transform the original orbit-based data to global gridded data? Any guides or advice would be highly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="5214" LastActivityDate="2019-05-20T02:53:47.663" Title="How to transform level 2 satellite retrievals to level 3 gridded data" Tags="|atmosphere|atmosphere-modelling|remote-sensing|satellites|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="16990" PostTypeId="1" AcceptedAnswerId="16993" CreationDate="2019-05-20T06:35:17.627" Score="3" ViewCount="226" Body="&lt;p&gt;I am looking for a way to detect shearlines or confluence regions such as that shown in the figure below (red dashed line). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was able to derive the stretching, shear, and total deformations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The  shearline coincides with the region of maximum stretching deformation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Currently, I am drawing the shearline manually. But I am wondering if there is a way to automatically detect this line or the deformation zone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am thinking of two ways&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Looking at the dynamic variables (i.e., stretching deformation)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Using Python's pattern recognition function to detect this kind of pattern.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Problems&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any suggestions on how I can detect this automatically. I don't know how to implement the above methods. I am not sure what criteria to set in order to draw the shearline.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am also new to Python so I don't know how to implement the second one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have wind data and calculated deformations in netcdf format. I uploaded the files to the following links:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.dropbox.com/s/ym5jo07cb7niqkw/T62_ncep_uwnd.nc?dl=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;UWND&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.dropbox.com/s/m40wu3al7tf32ut/T62_ncep_vwnd.nc?dl=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;VWND&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.dropbox.com/s/cfcq3awxe2a1tbo/deform.nc?dl=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Link to calculated deformation parameters&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The deformation parameters are calculated this way:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Y7aSt.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Y7aSt.png&quot; alt=&quot;Deformation parameters&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where A, B, and V are the shearing, stretching, and total deformation parameters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the deform.nc file, shear_sph(shearing deformation; A in the equation above); stretch_sph(stretching deformation; B in the equation B); deform_sph(total deformation; V in the equation above).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll appreciate any help about this matter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;SUMMARY&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am looking for the &lt;a href=&quot;https://www.ncl.ucar.edu/Document/Functions/Contributed/shear_stretch_deform.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCL Shear, stretch, deform&lt;/a&gt; functionality in Python. Are there any existing software packages or do I have to write my own ?&lt;/p&gt;&#xA;" OwnerUserId="16927" LastEditorUserId="16927" LastEditDate="2019-09-05T06:38:17.460" LastActivityDate="2019-09-05T06:38:17.460" Title="Locating shearlines or deformation zones in a map" Tags="|meteorology|python|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16991" PostTypeId="1" AcceptedAnswerId="16992" CreationDate="2019-05-20T09:55:16.073" Score="1" ViewCount="35" Body="&lt;p&gt;Due to the food chain and the cycle of life, matter is constantly moved between plants, primary consumers, secondary consumers, and so on, until the consumers die, giving matter they consumed back to the ecosystem via dung and corpses. This should mean that there is a constant flow of mass and energy moving through an ecosystem. Does that mean we could (theoretically) weigh a given ecosystem in metric tons?&lt;/p&gt;&#xA;" OwnerUserId="16928" LastActivityDate="2019-05-20T11:33:08.190" Title="If matter is constantly being cycled through an ecosystem, does that mean a given ecosystem has a fixed mass?" Tags="|ecology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16992" PostTypeId="2" ParentId="16991" CreationDate="2019-05-20T11:33:08.190" Score="2" Body="&lt;p&gt;You can always weigh the biomass of the (global) ecosystem in metric tons, or any other unit, even when this mass would not be constant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't see a reason why the total biospheric mass should be constant (maybe because it reached a saturation limit long ago) on short timescales. On long/geological timescales it is certainly not, as the available carbon, silicate, oxygen etc. for the bottom of the nutritional chains a.k.a. microbes, lichen, fungi... evolves, as the planet itself changes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is however not true for the total mass of Earth, which is essentially constant since its time of formation, but the biospheric mass is anyways only a small fraction thereof.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2019-05-20T11:33:08.190" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="16993" PostTypeId="2" ParentId="16990" CreationDate="2019-05-20T12:12:09.907" Score="2" Body="&lt;p&gt;I am not able to give full actual code in Python but I hope I can point you in the right direction if I were to go about calculating diffluence and confluence. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One can start with making a &lt;a href=&quot;https://matplotlib.org/gallery/images_contours_and_fields/plot_streamplot.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;streamlines plot using matplotlib first&lt;/a&gt;. Once you have that you need to get the actual streamlines data as described in this link - &#xA;&lt;a href=&quot;https://matplotlib.org/api/_as_gen/matplotlib.pyplot.streamplot.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://matplotlib.org/api/_as_gen/matplotlib.pyplot.streamplot.html&lt;/a&gt; and that data structure is given as LineCollection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For each streamline in that LineCollection you will need to calculate &lt;a href=&quot;https://scicomp.stackexchange.com/questions/16444/determine-unit-outward-normal-vector-for-a-curve/16445#16445&quot;&gt;tangential and normal vectors&lt;/a&gt; based on the idea of a localized Cartesian system with a origin centered on somewhere along the streamline.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once you have the tangential and normal vectors you will need to use this equation i.e. the divergence in natural coordinates&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ \nabla . v_h = (e_n \frac {\partial e_s}{\partial n} * v_h) + \frac {\partial v_h}{\partial s}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using a combination of &lt;a href=&quot;https://en.wikipedia.org/wiki/Frenet%E2%80%93Serret_formulas&quot; rel=&quot;nofollow noreferrer&quot;&gt;Frenet Serret formula&lt;/a&gt; this can be shown to be equal to &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac {|v_h|}{R_n} + \frac {\partial v_h}{\partial s} $$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From your perspective you only want the first term on that equation to calculate diffluence and confluence. So &lt;span class=&quot;math-container&quot;&gt;$R_n$&lt;/span&gt; is the radius of curvature of the normal vector (which you already calculated before). So in order to calculate the radius of curvature you can use this &lt;a href=&quot;https://github.com/bdhammel/least-squares-ellipse-fitting&quot; rel=&quot;nofollow noreferrer&quot;&gt;python code for least squares fitting&lt;/a&gt; (using the approach of least squares - obtain the ellipse and then calculate the radius). If the radius is  positive i..e &lt;span class=&quot;math-container&quot;&gt;$R_n &amp;gt;0 $&lt;/span&gt; then you have an area of diffluence and negative then confluence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are looking for the exact &lt;a href=&quot;https://www.ncl.ucar.edu/Document/Functions/Contributed/shear_stretch_deform.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCL shear stretch deform&lt;/a&gt; in Python what you can do is to use this package in python &lt;a href=&quot;https://pypi.org/project/pyspharm/&quot; rel=&quot;nofollow noreferrer&quot;&gt;pyspharm&lt;/a&gt;. The data has to be global and then you need to orient the grid in a south to north direction. Once you have that you can use that package to calculate the shear, stretch and deformation parameters by using the &lt;a href=&quot;https://github.com/jswhit/pyspharm/blob/master/Lib/spharm.py#L845&quot; rel=&quot;nofollow noreferrer&quot;&gt;pyspharm's &lt;strong&gt;getgrad()&lt;/strong&gt;&lt;/a&gt; method to calculate the vector gradient of the wind vectors. If you pass in the components of the wind vectors(both u and v) to getgrad() you will get the zonal and meridional components of the gradient of the wind vectors. Adding and subtracting them will get you the shear and stretch. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sample code&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt; from spharm import Spharmt&#xA;&#xA; uspectral = Spharmt.grdtospec(u,ntruncation)&#xA; vspectral = Spharmt.grdtospec(v,ntruncation)&#xA; dudx,dudy = Spharmt.getgrad(uspectral)&#xA; dvdx,dvdy = Spharmt.getgrad(vspectral)&#xA; #shear and stretch&#xA; shear = dvdx + dudy&#xA; stretch = dudx - dvdy&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-07-01T02:44:11.997" LastActivityDate="2019-07-01T02:44:11.997" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="16997" PostTypeId="1" AcceptedAnswerId="17005" CreationDate="2019-05-20T17:46:53.043" Score="2" ViewCount="536" Body="&lt;p&gt;I've recently listend to a talk of Prof. Gernot Patzelt, Austrian Geographer and High Altitude Mountain Researcher. In this talk he describes that scientists find rests of trees and moorland apearing under the melting ice in the alps (Source: &lt;a href=&quot;https://www.eike-klima-energie.eu/tag/patzelt/?print=print-search&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.eike-klima-energie.eu/tag/patzelt/?print=print-search&lt;/a&gt;). He concludes that it must have been much warmer in times when mankind was not yet able to bring CO2 in the atmosphere and there is no causal relationship between the melting of the glaciers in the alps and the amount of CO2 in the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These arguments are used by a lot climate-change-sceptics. This is why I'm looking for counter-arguments for this line of argument. As far as I can see melting glaciers can be one indication for a regional or global warming, no matter what's the reason for that warming. So I guess he mixes up indications for a warming with the proof of causality (CO2 -&gt; global warming)? Correct? Any other ideas?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Martina&lt;/p&gt;&#xA;" OwnerUserId="16934" LastActivityDate="2019-05-21T07:31:37.537" Title="Looking for counter-arguments concerning the melting of glaciers in the alps in the context of global warming" Tags="|climate-change|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17000" PostTypeId="1" CreationDate="2019-05-20T20:05:33.477" Score="4" ViewCount="211" Body="&lt;p&gt;I see this term being used everywhere, but I have not been able to find a formal definition for &quot;ambient aerosols&quot;.&lt;/p&gt;&#xA;" OwnerUserId="14092" LastActivityDate="2019-05-25T19:46:07.970" Title="What exactly are &quot;ambient aerosols&quot;?" Tags="|meteorology|atmospheric-chemistry|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17001" PostTypeId="2" ParentId="16997" CreationDate="2019-05-21T02:25:23.483" Score="0" Body="&lt;p&gt;He doesn't seem to be using the existence of the trees to argue against AGW. It was warmer:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Holocene Climate Optimum (HCO) was a warm period during roughly the interval 9,000 to 5,000 years BP&#xA;  &lt;a href=&quot;https://en.wikipedia.org/wiki/Holocene_climatic_optimum&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;&#xA;  &lt;a href=&quot;https://i.stack.imgur.com/Jm2kA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Jm2kA.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;He complains about a lack of correlation over the 60 years preceding 2010. He is still active, mentioned in &lt;a href=&quot;https://www.theguardian.com/environment/2019/may/14/germanys-afd-attacks-greta-thunberg-as-it-embraces-climate-denial&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-05-21T02:25:23.483" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17003" PostTypeId="2" ParentId="16997" CreationDate="2019-05-21T05:56:44.377" Score="0" Body="&lt;p&gt;Polarization and politicization makes us dumb. Climate is complex and there should be periods of global warming and periods of global cooling. Big amplitude changes in periods of about 100,000 years and less big amplitudes irregular and capricious in between. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is no doubt that increased atmospheric carbon dioxide has a greenhouse effect and that global cooling decrease the rate of atmospheric carbon dioxide. More CO2 makes it warmer and the warmer the more CO2 is released from the sees. And opposite, cooling decrease the rate of CO2 which makes it cooler. This amplifying feedback could explain a good deal of the short time irregularity of global temperatures. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As it seems we are heading for long time global warming since about 20,000 years or so. Historically the warming periods rather rapidly turn into cooling periods, both in short and long time perspective. What has happened in the last 150 years is that industrial emitted CO2 has reached really extreme levels on the top of the natural global warming, at the same time that the temperature anomalies is very high. And this is alarming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of the energy of global warming is stored in the oceans and it is an enormous amount of extra energy that has ben stored between 1970 and 2003: 200,000,000,000,000,000,000,000 Joules. Which correspond to 40 billion atomic Hiroshima bombs (which is about 5 bombs per person of today earth population), or to 200 million ordinary thunderstorms, or to to 4,000 ordinary hurricane days.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oRJ3E.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oRJ3E.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Glacial melting is not only depending of human activities, it naturally suppresses the naturally occurred CO2 amplified feedback and should be expected to alter, but since 1970 the ice is rapidly melting all around the world.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If we are lucky, the industrial emissions is responsible for all this&#xA;  warming and melting. The worse alternative is that the 3 million year&#xA;  record of atmospheric carbon dioxide is going to act upon the top of&#xA;  what is already alarmingly high.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="16809" LastActivityDate="2019-05-21T05:56:44.377" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17004" PostTypeId="1" CreationDate="2019-05-21T06:40:25.840" Score="4" ViewCount="123" Body="&lt;p&gt;I am trying to locate saddle points or commonly known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Col_(meteorology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;col&quot; in synoptic meteorology&lt;/a&gt;. This is &quot;z&quot; in the following figure.&lt;a href=&quot;https://i.stack.imgur.com/Lm2MF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Lm2MF.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&#xA;Here are some of the references regarding this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;a). &lt;a href=&quot;http://www.zamg.ac.at/docu/Manual/SatManu/main.htm?/docu/Manual/SatManu/CMs/Def/backgr.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.zamg.ac.at/docu/Manual/SatManu/main.htm?/docu/Manual/SatManu/CMs/Def/backgr.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;b). &lt;a href=&quot;https://www.meted.ucar.edu/labs/synoptic/kinematics/vort_defzones/navmenu.php?tab=1&amp;amp;page=3-0-0&amp;amp;type=flash&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.meted.ucar.edu/labs/synoptic/kinematics/vort_defzones/navmenu.php?tab=1&amp;amp;page=3-0-0&amp;amp;type=flash&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What I want&lt;/strong&gt;&#xA;1. I would like to know what are the characteristics of these points in terms of divergence, sea level pressure, relative humidity or moisture, etc.&#xA;I will be automatically detecting these points from the given characteristics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll appreciate any help.&lt;/p&gt;&#xA;" OwnerUserId="16927" LastEditorDisplayName="user1066" LastEditDate="2019-05-21T07:11:53.807" LastActivityDate="2019-05-21T07:11:53.807" Title="Characteristics of saddle points in stream line charts" Tags="|meteorology|synoptic|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="17005" PostTypeId="2" ParentId="16997" CreationDate="2019-05-21T07:31:37.537" Score="1" Body="&lt;p&gt;&lt;em&gt;He concludes that it must have been much warmer in times when mankind was not yet able to bring CO2 in the atmosphere and there is no causal relationship between the melting of the glaciers in the alps and the amount of CO2 in the atmosphere.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This incorrectly collapses several things.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Mankind is not the only cause of CO2 in the atmosphere. There have been warmer periods caused by CO2, but it was not man-made.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;I think you slightly misrepresented his words by quoting &lt;em&gt;no causal relationship between the melting of the glaciers in the alps and the amount of CO2 in the atmosphere&lt;/em&gt;, but actually meaning &lt;em&gt;is no causal relationship between the melting of the glaciers in the alps and the amount of&lt;/em&gt; &lt;strong&gt;man-made&lt;/strong&gt; &lt;em&gt;CO2 in the atmosphere&lt;/em&gt;. If not, that would mean he is denying &lt;em&gt;any&lt;/em&gt; relationship between CO2 and temperature, which would disqualify him as a knowledgable person.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="595" LastActivityDate="2019-05-21T07:31:37.537" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17008" PostTypeId="1" CreationDate="2019-05-21T13:22:41.493" Score="4" ViewCount="224" Body="&lt;p&gt;My understanding of plate tectonics is that in the middle of the oceans magma rises from the mantle of the earth, cools and then spreads out, building up the sea floor. These places are pretty obvious because they have lava coming out of them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, there are places that sink into the earth, &lt;em&gt;subduction zones&lt;/em&gt;, where the reverse happens; the existing crust slides into the mantle. Is there any place where this is visible, like the lava, or does it only take place invisibly far below the surface?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, let's say I have an object, like a shipwreck hulk. If I put the hulk on the sea floor in a subduction zone will it get sucked into the earth and vanish? If so, how long would it take for it to disappear?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2019-05-23T06:42:12.313" Title="Is there a place where the sea floor descends into the mantle of the earth?" Tags="|plate-tectonics|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17010" PostTypeId="2" ParentId="16962" CreationDate="2019-05-21T15:32:37.477" Score="4" Body="&lt;p&gt;I had the same problem but have just found the solution after an hour or so of trawling through forums! The problem was that the code 'api.py' could not find the '.cdsapirc' file. The file type has to actually be 'CDSAPIRC' and not a 'txt' file. The icon for the file will then be displayed in your folder as blank and the name will be '.cdsapirc'. I found the solution on here: &lt;a href=&quot;https://www.wikihow.com/Create-and-Delete-Files-and-Directories-from-Windows-Command-Prompt&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.wikihow.com/Create-and-Delete-Files-and-Directories-from-Windows-Command-Prompt&lt;/a&gt;. I created the file using the following steps:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Navigate to 'C:\Users\username' (or you can just move it later). &lt;/li&gt;&#xA;&lt;li&gt;In Command Prompt, write 'type nul &gt; .cdsapirc' and press Enter. &lt;/li&gt;&#xA;&lt;li&gt;Right-click the file and press 'Edit with Notepad++' (probably works with other programs).   &lt;/li&gt;&#xA;&lt;li&gt;Paste the text that you already mentioned (key, etc). &lt;/li&gt;&#xA;&lt;li&gt;Save and close the document.  &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Hope that works :)&lt;/p&gt;&#xA;" OwnerUserId="16942" LastActivityDate="2019-05-21T15:32:37.477" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17017" PostTypeId="1" AcceptedAnswerId="18719" CreationDate="2019-05-21T22:56:56.753" Score="5" ViewCount="251" Body="&lt;p&gt;I have two questions regarding coral reef and volcanic islands.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When a new volcanic island is formed, how much time generaly passes before a coral reef starts to form around the island?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another question: Are there any volcanic islands in warm pacific waters which do not show fringing or a barrier reef? If so, is this because the island was formed recently and is still too hot for a coral reef to flourish?&lt;/p&gt;&#xA;" OwnerUserId="16949" LastEditorUserId="39" LastEditDate="2019-05-23T16:58:18.387" LastActivityDate="2021-09-09T06:14:13.280" Title="Coral Reef and Volcanic Islands" Tags="|oceanography|volcanology|volcanic-eruption|pacific|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17019" PostTypeId="2" ParentId="15267" CreationDate="2019-05-22T06:56:45.853" Score="5" Body="&lt;p&gt;As a prescript, your question is firmly within the field of Glacio-Isostatic Adjustment (GIA) modeling of the Earth and the sea level. The main scientific names doing research in this direction are Jerry Mitrovica, W.R. Peltier, Roblyn Kendall, Glenn Milne, Kurt Lambeck, Giorgio Spada, and probably some more that I'm forgetting. It all comes down to, basically, the 'Sea Level Equation' (SLE), &lt;a href=&quot;https://en.wikipedia.org/wiki/Sea_level_equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Sea_level_equation&lt;/a&gt; .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Copying straight from Wikipedia, the simplest form of the sea level change &lt;span class=&quot;math-container&quot;&gt;$S$&lt;/span&gt; is given by the difference between the shift in the geoid (i.e., the effects you describe) &lt;span class=&quot;math-container&quot;&gt;$N$&lt;/span&gt; and the changes in vertical land positions (&lt;span class=&quot;math-container&quot;&gt;$U$&lt;/span&gt;):&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ S = N-U .$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is this second factor, the response of the Earth and ocean bottom to the changing loads, that you didn't take into account, that can lead to some serious local deviations from the gravitational aspect alone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See Figure 2-2 from &lt;a href=&quot;http://skb.se/upload/publications/pdf/TR-09-11.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://skb.se/upload/publications/pdf/TR-09-11.pdf&lt;/a&gt;, copied here below:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/MHH3E.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MHH3E.png&quot; alt=&quot;Figure of GIA sea level&quot;&gt;&lt;/a&gt;&#xA;&lt;strong&gt;Figure 2-2.&lt;/strong&gt; &lt;em&gt;(a) Ocean height is perturbed upwards due to the gravitational attraction of the ice sheet. Solid Earth is depressed downwards due to the mass of the ice sheet. (b) Local relative sea-level fall due to a decrease in gravitational attraction by the ice (red dashed line shows previous position), combined with solid Earth rebound (green line shows previous positions) due to the ice sheet having a smaller mass. Far-field sea-level rise is due to the addition of meltwater into the ocean. Adapted from Tamisiea et al. 2003.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;After staring at this figure for a while, you may appreciate that, indeed, from state (a) to (b) as the ice cap melts, the far-field sea level rises through addition of fluid water and a drop in the gravitational attraction nearby. However, also, now that the ice cap is smaller and less heavy, the solid Earth responds by moving up! Hence, 'close' to the ice cap, the sea level doesn't drop as much as you would expect from amount of fluid water + gravity alone. NB: the same happens with the oceans: adding more water to the oceans depresses them, see page 26, figure 11 here &lt;a href=&quot;https://arxiv.org/pdf/1212.5061.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://arxiv.org/pdf/1212.5061.pdf&lt;/a&gt;  with the 'relative sea level change' around the Mediterranean Sea, compared to the present. Copied here below is one for 10 thousand years ago:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/BOuoU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BOuoU.png&quot; alt=&quot;mediterranean&quot;&gt;&lt;/a&gt;&#xA;Apparently, the sea level has risen by 30 meters in the center of the sea, but only about 22 meters on the edges. The reason is that the Mediterranean sea, from 10 thousand years ago to today, gained more mass, which caused it to depress the sea bottom / Earth's crust in the center! Hence, it had to rise &lt;em&gt;even more&lt;/em&gt; in the center (compared to the coast lines) to create a flat surface today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The difficult thing is that these are non-local processes. You kind of need to know about such local Mediterranean changes to make an accurate prediction for the sea level in, e.g., the Gulf of Mexico or so, because it changes the center of mass and the fluid sea water budget that can be distributed!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So with respect to your question, I absolutely think you are right that gravity is an important aspect, and 40 meters relative sea level change differences due in the hemispheres are absolutely possible for the reason you mention. If the melting is instantaneous, this is the main aspect. However, if you wait a century or so, the Earth's deformations start to kick in, can play a serious role, and can dramatically affect the sea level distribution again, in not easily foreseeable ways!&lt;/p&gt;&#xA;" OwnerUserId="12155" LastEditorUserId="39" LastEditDate="2019-05-22T22:14:42.513" LastActivityDate="2019-05-22T22:14:42.513" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17020" PostTypeId="1" CreationDate="2019-05-22T10:55:11.897" Score="5" ViewCount="304" Body="&lt;p&gt;I have only few station inside the watershed so I want to use the stations outside if I can to get better results&lt;/p&gt;&#xA;" OwnerUserId="16953" LastEditorUserId="1411" LastEditDate="2019-05-24T14:38:35.437" LastActivityDate="2019-05-25T12:14:19.727" Title="Can I interpolate rainfall data from stations outside of watershed for the watershed?" Tags="|meteorology|hydrology|precipitation|watershed|interpolation|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17021" PostTypeId="1" AcceptedAnswerId="17043" CreationDate="2019-05-22T12:43:23.010" Score="6" ViewCount="1787" Body="&lt;p&gt;I recently read on another SE site that there's a limitation on how deep we can dig into the earth.&lt;/p&gt;&#xA;&lt;p&gt;A Google search reveals that temperature is the problem.&lt;/p&gt;&#xA;&lt;p&gt;I quote from a Popular Mechanics article, &lt;a href=&quot;https://www.popularmechanics.com/technology/infrastructure/a27225/deepest-possible-hole/&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;How Deep Can You Dig a Hole?&lt;/em&gt;&lt;/a&gt;, which speaks on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kola Superdeep Borehole&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The limiting factor is almost always the temperature. The Kola was abandoned in 1992 when workers hit &lt;strong&gt;356 degrees Fahrenheit&lt;/strong&gt;, far hotter than they had anticipated. The tunnel was eventually closed off in the early 2000's.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;356&lt;span class=&quot;math-container&quot;&gt;$^\circ$&lt;/span&gt;F is 180&lt;span class=&quot;math-container&quot;&gt;$^\circ$&lt;/span&gt;C, for those of you who don't get Fahrenheit, like me.&lt;/p&gt;&#xA;&lt;p&gt;Iron's melting point is well above 1000&lt;span class=&quot;math-container&quot;&gt;$^\circ$&lt;/span&gt;C, and I think it is okay to assume most of our machines have iron as a major constituent. Alloys with iron will only have higher melting points.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Why is 180&lt;span class=&quot;math-container&quot;&gt;$^\circ$&lt;/span&gt;C a problem? Why can't we dig deeper?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="16954" LastEditorUserId="18088" LastEditDate="2024-01-19T06:34:41.643" LastActivityDate="2024-01-19T06:34:41.643" Title="Why can't we dig deeper?" Tags="|geology|mining|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="17022" PostTypeId="2" ParentId="16777" CreationDate="2019-05-22T22:24:01.940" Score="6" Body="&lt;p&gt;The question is slightly confused, because reducing the temperature of the oceans, in a direct sense, doesn't require energy - it releases it. The amount that is released is simply related to the mass and specific heat capacity of seawater, as you suggest.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The missing question, though, is &lt;em&gt;why&lt;/em&gt; the ocean is cooling. For it to happen naturally and simply release energy, it would need to be because its surroundings (e.g. the air) were cooler. If you want to actively cool the sea, then yes, that is going to consume energy. If the cooling has approximately the same level of performance as building-sized air conditioning, the power used by the cooling apparatus will be about 40% of the rate at which the energy is removed (and remember that this is not just the total energy divided by the time, because more heat will be leaking back in while you do it).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Leaving aside the, uh, engineering challenges of this scale of cooling, this leads to a question as to &lt;em&gt;why&lt;/em&gt; one might want to do this. Remember that unless you devise some complex system to radiate this heat into space from above the atmosphere, you're going to be releasing the same heat into the same global climate system, plus the additional 40% that you've used to move it around.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-05-22T22:24:01.940" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17023" PostTypeId="2" ParentId="17020" CreationDate="2019-05-23T03:49:24.123" Score="5" Body="&lt;p&gt;Yes, you can interpolate the rainfall from stations outside the watershed. However, the quality of the interpolation will depend on the distance between the stations and the watershed, the prevailing weather patterns, and to some extent the topography.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, it probably wouldn't be appropriate to use a station on the rainy side of a mountain divide in estimating rainfall in the rainshadow. One way to get an idea on how good you estimates are is to compare the actual rainfall at a station with the interpolated rainfall at that location, when you leave it out of the dataset.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2019-05-23T03:49:24.123" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17025" PostTypeId="1" CreationDate="2019-05-23T06:13:48.590" Score="4" ViewCount="73" Body="&lt;p&gt;I am trying to understand the basic dynamics of MJO, where I find several studies which relate it to the initiation of equatorial Rossby and Kelvin waves. Though MJO is an eastward propagating wave, I can relate it to the existence of Kelvin waves during that time but I am not getting any insight about the initiation of a westward wave. I think that the westward motion could be possible only due to the reflection of easterly wave through a boundary. Please correct me with the actual fact and its underlying mechanism.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am mentioning some of the online sources which inform about the above mentioned fact but I am not getting the answers from any research papers&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://ams.confex.com/ams/98Annual/webprogram/Paper324264.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://ams.confex.com/ams/98Annual/webprogram/Paper324264.html&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.cwb.gov.tw/V7/climate/climate_info/information/lectures/59/CWB2015-10-02_Bin_Wang2.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.cwb.gov.tw/V7/climate/climate_info/information/lectures/59/CWB2015-10-02_Bin_Wang2.pdf&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Actually I could not find the detailed study for source 1 but I found similar statements (Kelvin-Rossby relation) in other studies that made me more confused. The second mention raises this issue, they talk about Matsuno-Gill theory and the usage of equatorial waves in it but I am unable to get any understanding of their model about how it emerged from (A description is attached here).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://atmos.washington.edu/~dargan/591/591_8.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://atmos.washington.edu/~dargan/591/591_8.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11162" LastEditorUserId="11162" LastEditDate="2019-05-23T10:32:52.217" LastActivityDate="2019-05-23T10:32:52.217" Title="Initiation of Rossby waves during MJO" Tags="|meteorology|atmospheric-circulation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17026" PostTypeId="2" ParentId="17008" CreationDate="2019-05-23T06:21:27.583" Score="2" Body="&lt;p&gt;Subduction zones are only observable indirectly through the typical volcanos in these regions (stratovulcanos like Krakatau or Pinatubo on the surface of the continental plate). Another form of typical subduction volcanos are the &quot;Petit Spots&quot; only described for the first time in 2001 by geologists from Japan. These litle volcanos appear under the water surface on top of the oceanic plate at the outer bulge of the oceanic plate.&#xA;This is because the real subduction area  lies normally about 3000-4000 metres below the surrounding ocean surface and is covered with sediments.&#xA;In most cases subduction is not a smooth and steady process but it proceeds with bigger or smaller earthquakes, depending on the material of the plates. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That means if you drop your spaceship in that zone it will be covered with a huge amount of sediments through the centuries, while at the same time these sediments in the deep sea trench compress the spaceship to a nice geological singularity. By the time it reaches the contact zone between oceanic plate and the continental plate it will be destroyed and with every little tug of the next earthquake it will be more pulverized and transported some centimetres further under the continental plate...&lt;/p&gt;&#xA;" OwnerUserId="16934" LastActivityDate="2019-05-23T06:21:27.583" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17027" PostTypeId="2" ParentId="17008" CreationDate="2019-05-23T06:42:12.313" Score="3" Body="&lt;p&gt;The subduction zones are more easily spotted by the phenomena they cause in the subsurface than their features on the surface. I found this schematic image which shows almost all the features, from &lt;a href=&quot;https://www.researchgate.net/publication/318684905_The_Nahuel_Niyeu_basin_A_Cambrian_forearc_basin_in_the_eastern_North_Patagonian_Massif&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/publication/318684905_The_Nahuel_Niyeu_basin_A_Cambrian_forearc_basin_in_the_eastern_North_Patagonian_Massif&lt;/a&gt; :&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Rggn5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Rggn5.png&quot; alt=&quot;subduction zone&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So what you see is the thin black plate subducting under the grey continental rocks. There are two features that it causes in an indirect way.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The first of those is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Forearc&quot; rel=&quot;nofollow noreferrer&quot;&gt;forearc basin&lt;/a&gt;, which is a sometimes present region with thrust faults in the direction of the subduction point. Thus, there is a local basin with a lot of space for sedimentation.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The volcanism, then, is the most obvious and always-present feature. All the chemicals that the ocean floor brings into the Earth at relatively low temperature create a 'melt' that can eventually reach the Earth's surface.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The reason why we don't see the actual subduction happening with our own eyes is because of the formation of the 'accretionary prism'. This is the triangle-shaped feature on the figure. It consists of sediment that is held on the interface between the moving oceanic plate and the stationary continental plate. It's a bit like a bulldozer. Hence, the real subduction action is covered by kilometers of piled up sediment! The deepest natural trench in the world, the Mariana Trench, is only about 11 km deep, while the continental plate is probably at least ~40 km deep. Hence, we don't really see the actual subduction in action...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have a shripwreck hulk and place it in the Mariana trench, it will get covered with sediment with a speed of &lt;a href=&quot;https://scripps.ucsd.edu/biblio/provenances-distribution-and-accumulation-organic-matter-southern-mariana-trench-rim-and&quot; rel=&quot;nofollow noreferrer&quot;&gt;~0.02cm/year&lt;/a&gt;, so assuming your ship is about 30 meters high it will take 150 000 years before it is covered and can become part of the accretionary prism. Then it has to be dragged into the Earth somehow. The Nazca plate moves at &lt;a href=&quot;https://en.wikipedia.org/wiki/Nazca_Plate&quot; rel=&quot;nofollow noreferrer&quot;&gt;~5 cm/year&lt;/a&gt;, so it'll be moved by 7.5 kilometers forward. As I wrote, it'll have to subduct at least 30 more kilometers before it's below any continental plate, which would take at least 600 000 years at the speed of the plate motion, and assuming that it somehow moves at the same speed as the crust rather than getting bulldozered into the accretionary prism. In other words, it would probably take much much longer in practice before it reached far enough down. As said, that means that in the meantime your space ship will have been chemically weathered and mechanically deformed (by the enormous mass of sediments), and won't really be recognizable as a space ship anymore!&lt;/p&gt;&#xA;" OwnerUserId="12155" LastActivityDate="2019-05-23T06:42:12.313" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17028" PostTypeId="1" AcceptedAnswerId="17029" CreationDate="2019-05-23T10:04:26.753" Score="1" ViewCount="245" Body="&lt;p&gt;Except a hypothesized orbital forcing! Ice cores shows that there are several irregular sharp temperature peaks in between of the big 100,000 years glaciations. What could cause those peaks? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Almost all energy excess is stored in the oceans and common sense says that there have to be a threshold for how much energy the oceans can take up without drastically changing the climate. There are two possibilities: either there is a turn to cooling down the oceans or there isn't.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could the energy from the oceans take over the climate system totally for a time long enough to be cooled down? Could the energy from the oceans, if big enough cause global storms independent of the insolation? Convective clouds transport warm vapor high up in troposphere where condensation release an enormous amount of energy - mostly as heat energy that spreads from there. Could a global cover of convective clouds be maintained entirely by the ocean heat content, if big enough? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IVr0U.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IVr0U.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the diagram, there is a well defined peek about 50,000 years ago, for example. Sudden up and sudden down. Increased insolation (or something else) caused a sudden warming, that &quot;immediately&quot; turned back. Could it have been caused by a long time of storms and convection?&lt;/p&gt;&#xA;" OwnerUserId="16809" LastEditorUserId="16809" LastEditDate="2019-05-23T18:07:44.877" LastActivityDate="2019-05-27T17:58:53.193" Title="What could cause a turn from global warming to global cooling?" Tags="|climate-change|oceanography|glaciation|convection|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17029" PostTypeId="2" ParentId="17028" CreationDate="2019-05-23T14:12:32.423" Score="2" Body="&lt;p&gt;Pleistocene's climate variations are well correlated with Milhankovitch Cycles. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Variations in &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;nofollow noreferrer&quot;&gt;eccentricity&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Axial_tilt&quot; rel=&quot;nofollow noreferrer&quot;&gt;axial tilt&lt;/a&gt;, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Precession&quot; rel=&quot;nofollow noreferrer&quot;&gt;precession&lt;/a&gt; of the Earth's&#xA;  orbit resulted in cyclical variation in the solar radiation reaching&#xA;  the Earth, and that this orbital forcing strongly influenced climatic&#xA;  patterns on Earth.&quot;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;nofollow noreferrer&quot;&gt;Milhankovitch Cycles, Wikipedia&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;At this graph you can see eccentricity explains major Oxygen &lt;span class=&quot;math-container&quot;&gt;$δ18$&lt;/span&gt; variations at Pleistocene oceans. &lt;span class=&quot;math-container&quot;&gt;$δ18$&lt;/span&gt; is a known proxy for temperature.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wu0WZ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wu0WZ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: &lt;a href=&quot;http://euanmearns.com/the-ice-man-cometh/&quot; rel=&quot;nofollow noreferrer&quot;&gt;euanmearns.com&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The minor peaks are Earth's internal forces reaction to changes on solar radiation. Earth has subsystems that store and interchange the energy received from the Sun, resulting oscillatory climate tendencies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Aswell as the atmospere and the hydrosphere, cryosphere has internal forces as a subsystem; and oscillatory events (development of ice-break of ice). One example of punctual changes due to cryosphere internal forces dynamics are &lt;a href=&quot;https://en.wikipedia.org/wiki/Heinrich_event&quot; rel=&quot;nofollow noreferrer&quot;&gt;Heinrich Events&lt;/a&gt;, that can influence climate at minor scale than eccentricity does and be correlated with some of the peaks your graph shows.&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-05-27T17:58:53.193" LastActivityDate="2019-05-27T17:58:53.193" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17033" PostTypeId="1" AcceptedAnswerId="17040" CreationDate="2019-05-24T07:05:52.177" Score="1" ViewCount="613" Body="&lt;p&gt;How do you distinguish sea cave from sea arch?&#xA;If I want to classify a crack of sea cliff as sea cave, has it to have a dead end? Would you call a geological formation as a sea cave even a kayak can pass through?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cheers!&lt;/p&gt;&#xA;" OwnerUserId="16949" LastActivityDate="2019-05-27T02:47:03.503" Title="Sea cave vs Sea arch" Tags="|oceanography|waves|geomorphology|erosion|cavern|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17035" PostTypeId="1" CreationDate="2019-05-24T11:03:59.983" Score="1" ViewCount="1684" Body="&lt;p&gt;I know that Peninsula is much larger than a cape, but is there a definite way to differentiate them? I.e. by area- if the total area is larger than 30 sqkm, any headland is classified as peninsula..&lt;/p&gt;&#xA;" OwnerUserId="16949" LastEditorUserId="1411" LastEditDate="2019-05-27T23:31:32.010" LastActivityDate="2019-05-27T23:31:32.010" Title="Peninsula vs Cape" Tags="|geology|geography|geomorphology|" AnswerCount="1" CommentCount="4" ClosedDate="2019-05-24T17:22:44.253" ContentLicense="CC BY-SA 4.0" />
  <row Id="17036" PostTypeId="2" ParentId="17035" CreationDate="2019-05-24T13:46:15.393" Score="4" Body="&lt;p&gt;First let's define the terms:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Peninsula: A headland or promontory surrounded by water but connected to the mainland by a neck or isthmus. &lt;a href=&quot;https://www.wiley.com/en-us/The+Dictionary+of+Physical+Geography%2C+3rd+Edition-p-9781118687437&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This &lt;a href=&quot;https://www.nationalgeographic.org/encyclopedia/peninsula/&quot; rel=&quot;nofollow noreferrer&quot;&gt;definition&lt;/a&gt; is similar to the aforementioned and provide a few examples, underlining that the size (scale) is not an important criteria characterizing peninsulas. For example Baja California (Mexico) is 143000 km^2 in surface. Gaspésie (Québec, Eastern Canada) is 30000+ km^2. The Korean peninsula is more than 200000 km^2. Peninsulas can be of any size in surface if it meet the above definition. Normal usage of this term target large headlands surrounded by water but does not disqualify similar but smaller landforms even if unusual.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nationalgeographic.org/encyclopedia/cape/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cape&lt;/a&gt;: A marked change or discontinuity in trend of the coastline. This change is often a high point of land extending in the water, possibly because the rock formation at the extrusion is harder or more resistant to erosion than the surrounding coastline system. A cape or many capes can be featured on a peninsula (but typically not the other way around). Normally, cape are smaller than peninsulas. Cape of Good Hope (South Africa) and the North Cape (Norway) are examples of capes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Differentiation:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;strong&gt;Cape&lt;/strong&gt; need to be a feature of the coastline, such as a discontinuity, or a point of land extruding from the coastline toward the deep sea. The coastline can be an island or a big mass of land and the cape a single feature along the coastline. The scale to consider here is the coastline, and the cape being one out of the ordinary extruding component of the coastline.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;strong&gt;Peninsula&lt;/strong&gt; definition is loose unlike the cape definition. By typical usage peninsulas are much wider and longer than any capes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Like many of the concepts in geography, terms and definitions are open to debate or interchangeable, so I would not say there is a precise threshold separating capes from peninsulas. But I am pretty sure, using the existing definitions, that I can properly name those landforms most of the time when I see it.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2019-05-24T13:46:15.393" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17037" PostTypeId="1" CreationDate="2019-05-24T14:02:16.237" Score="3" ViewCount="45" Body="&lt;p&gt;I was reading about the ice age when temperature dropped 11 celsius degrees in relation with our current temperature. Then I found another article which says the temperature fluctuated 15 degree celsius.&#xA; &lt;a href=&quot;https://phys.org/news/2017-06-scientists-mysterious-ice-age-temperature.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scientists throw light on mysterious ice age temperature jumps&lt;/a&gt; &#xA;Speaking of times where Earth was inhabited by humans, and speaking about the average temperature of the planet, what's the largest known range of natural temperature variations the Earth had? Are those 11/15 degrees celsius the largest natural range of temperature changes Earth experienced or were there times Earth was hotter than now, or colder than the ice age, making the range of natural temperatures existing in human inhabited Earth larger than that?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastEditorUserId="9635" LastEditDate="2019-05-24T17:57:02.877" LastActivityDate="2019-05-24T17:57:02.877" Title="What's the largest known range of natural temperature variations of human inhabited Earth across history?" Tags="|temperature|ice-age|natural-conditions|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17038" PostTypeId="2" ParentId="16976" CreationDate="2019-05-24T14:08:15.503" Score="1" Body="&lt;p&gt;I am working in an academic environment and I know these tools are still shown to undergrads along other modern photo-interpretation techniques.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Often, modern techniques are more straightforward and convenient. There is a wide coverage of decent, recent and cheap satellite images available, providing a lot to work with in a short amount of time, easily compared to the interpretation of orthophotos. Elevation models, multi-bands and high resolution are big plus for modern techniques in a GIS for instance. Not counting just bringing a drone and ortho-photograph everything.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where available stereo-pairs are somewhat older (50's to 80's) and of a limited/specific coverage depending on the region of interest - so this need to be considered.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I also use stereo-pairs when I go in a tent at the tip of the globe where technology break, battery drains and internet lack. Portable stereoscope work well in the field.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2019-05-24T14:08:15.503" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17039" PostTypeId="2" ParentId="17020" CreationDate="2019-05-24T14:54:43.487" Score="4" Body="&lt;p&gt;In short: Yes you can/should use stations outside of your watershed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More in detail: There is well known methods in hydrology to solve the situation you are presenting. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One simple method is to build Thiessen Polygons on your map to model the incoming precipitation in your target watershed using gauge station located inside and outside your watershed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The idea is to assign (mathematical) weights to each polygons (area covered by a station) by proportionally assigning a quantity of rain function of the area covered by the said polygon intersecting with your watershed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PQdPu.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PQdPu.jpg&quot; alt=&quot;Thiessen Polygons implementation example. Source: Encyclopedia of Hydrology and Water Resources&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is several other approaches to solve this problem: many examples are shown &lt;a href=&quot;https://www.weather.gov/abrfc/map&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. There is a varying level of complexity and precision for each approaches. Often, your specific case will be appropriate with certain methods only - depending on the nature of the data you have (or not) for your watershed.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastEditorUserId="1411" LastEditDate="2019-05-25T12:14:19.727" LastActivityDate="2019-05-25T12:14:19.727" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17040" PostTypeId="2" ParentId="17033" CreationDate="2019-05-24T15:56:06.610" Score="2" Body="&lt;p&gt;I don't know if there is a definition of the difference.  Sea caves are typically erosional features not solutional and do not have much length like typical limestone caves so to restrict them to only being a cave based on a totally dark section would force the reclassification of many sea caves to something else.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Typically an arch has an opening diameter greater than its length.  In our parts, Pacific Northwest North America, a sea cave can be just about any opening in the cliff where there is a section that is continuously shaded.  The cave can have multiple entrances.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2019-05-24T15:56:06.610" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17041" PostTypeId="1" CreationDate="2019-05-24T16:14:58.063" Score="1" ViewCount="128" Body="&lt;p&gt;I am a postdoctoral scholar who is interested participating in Antarctica fieldwork/exploration as a volunteer. My background is in biology, but I am happy to participate in any fieldwork opportunities, because I hope to use such an experience to better understand how teams perform effective science in harsh environments. I have worked in scientific teams in remote environments and believe I can grow a lot for future endeavors by working in even more harsh environments like Antarctica.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a side note, I am a U.S. citizen who has extensive experience overseas (especially in Japan).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the past few years, I have tried:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Contacting numerous scientists who lead Antarctica teamwork. 2) Contacting Palmer LTER and McMurdo LTER.&#xA;3) Applying to the ANSMET program. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far I have not had much luck, which is understandable given the limited slots. I wanted to inquire if anyone on this forum may know of other avenues someone in my position can apply to increase their chance of obtaining such a volunteer position? Any advice would be so very much appreciated! Thank you.&lt;/p&gt;&#xA;" OwnerUserId="16968" LastActivityDate="2019-05-27T13:57:09.963" Title="Young researcher hoping to volunteer for Antarctica fieldwork" Tags="|antarctic|field-measurements|antarctica|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17042" PostTypeId="1" AcceptedAnswerId="17097" CreationDate="2019-05-24T21:47:09.453" Score="6" ViewCount="179" Body="&lt;p&gt;There is a lot of interest in brown carbon in the atmospheric science community these days. There is a paper in the journal, &quot;Atmospheric Chemistry and Physics&quot; titled, &quot;Black carbon or brown carbon? The nature of light-absorbing carbonaceous aerosols&quot; by M.O. Andreae and A. Gelencser, which was published in 2006. However, after reading this paper, I feel more confused than before. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My second question is, &quot;What is the need to separate brown carbon from black carbon?&quot;&lt;/p&gt;&#xA;" OwnerUserId="14092" LastEditorUserId="2511" LastEditDate="2019-05-30T16:59:14.253" LastActivityDate="2019-05-30T16:59:14.253" Title="What is brown carbon?" Tags="|meteorology|atmospheric-chemistry|atmospheric-radiation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17043" PostTypeId="2" ParentId="17021" CreationDate="2019-05-25T14:11:20.883" Score="8" Body="&lt;p&gt;Here is a thermal profile of the borehole:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Source: Fig 5 in Yuri A. Popov, Sergei L. Pevzner, Vyacheslav P. Pimenov, Raisa A. Romushkevich,&#xA;New geothermal data from the Kola superdeep well SG-3,&#xA;Tectonophysics,&#xA;Volume 306, Issues 3–4,&#xA;1999,&#xA;Pages 345-366,&#xA;ISSN 0040-1951,&#xA;&lt;a href=&quot;https://doi.org/10.1016/S0040-1951(99)00065-7&quot; rel=&quot;noreferrer&quot;&gt;https://doi.org/10.1016/S0040-1951(99)00065-7&lt;/a&gt;.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Jeu7r.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Jeu7r.gif&quot; alt=&quot;Figure 5: Thermal Profile of Kola Super Deep&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This borehole is (almost) vertical and not an angle, so its depth is true (11662 m) and it is quite warm down there, around 180 degrees Celsius as shown in the above figure. I assume temperatures were similar in other shafts drilled at maximum depth at 12262 m. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The equipment they used initially for the 1982 borehole down to 11662 m was made to be able to work in thermal stability up to 200 degrees Celsius (Source: Kozlovsky, Yevgeny A., and N. I. Adrianov, eds. The superdeep well of the Kola Peninsula. Springer Berlin Heidelberg, 1987.) Consequently I assume the equipment used for the later shaft that reached 12262 m was of similar or better make than the original.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem is not the temperature against the barrel only: there is heat due to the shear (rotation) and let's not forget the weight of the shaft down the base. This is why the thermal stability of the system is to be considered in addition to the resistance of single parts of the drill system. So while hotter than they expected, it was within the operating range conform to the specifications of the make - but yet very near the thresholds and thus problematic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem lied also with the rock being more and more plastic deep down in the borehole, due to pressure, porosity and water, making it a very difficult challenge to keep the borehole open each time the shaft need to be replaced or removed, adding difficulties to this already never-been-done-before project.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So this sum of challenges are probable reason why the project was interrupted before reaching the initial goal of 15 km.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2019-05-25T14:11:20.883" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17045" PostTypeId="2" ParentId="17000" CreationDate="2019-05-25T19:46:07.970" Score="2" Body="&lt;p&gt;In the field, in which I work, the term _ambient aerosol` is related to the water content of aerosol particles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Commonly in the atmosphere, water is attached to particles. The amount of water attached to particles depends on the relative humidity (in ambient air). Increasing relative humidity means more water and, hence, larger particle/droplet diameter. When we provide a measured/modeled particle diameter, we need to note whether the diameter is given as &lt;em&gt;dry&lt;/em&gt;, as &lt;em&gt;wet at XX% relative humidity&lt;/em&gt; or as &lt;em&gt;wet at ambient relative humidity&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe it is also used in other contexts.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2019-05-25T19:46:07.970" CommentCount="0" CommunityOwnedDate="2019-05-25T19:46:07.970" ContentLicense="CC BY-SA 4.0" />
  <row Id="17046" PostTypeId="2" ParentId="10836" CreationDate="2019-05-25T20:17:23.713" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/srep33158&quot; rel=&quot;nofollow noreferrer&quot;&gt;Analogues to Mars Recurring Slope Linea&lt;/a&gt; (RSL) is a current study topic in  Antarctica (Dry Valleys). On Earth, analogues are known as water tracks, which are linear zones of higher moisture along slopes in polar regions where water transit during snowmelt. This figure from Ward Hunt Island (NU, Canada) show well developed and typical water tracks.&lt;a href=&quot;https://i.stack.imgur.com/gzHOI.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gzHOI.jpg&quot; alt=&quot;Water Tracks on Ward Hunt Island&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source:  Water tracks in the High Arctic: a hydrological network dominated by rapid subsurface flow through patterned ground Michel Paquette et al. Arctic Science, 2017, 3:334-353, &lt;a href=&quot;https://doi.org/10.1139/as-2016-0014&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1139/as-2016-0014&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On Earth, as shown on this picture from Ward Hunt Island, water tracks are from snowmelt and thus not from brine, &lt;a href=&quot;https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/123/11-12/2295/125616&quot; rel=&quot;nofollow noreferrer&quot;&gt;unlike in Antarctica where brine water&lt;/a&gt; as runoff is common.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Water tracks share many morphological and seasonal characteristics with RSL, including downslope propagation of linear or branching patterns of surface darkening, growth during spring/summer seasons, and fading during winter&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Saline fluids associated with water track flow are sourced by snowmelt, shallow ground ice melt, and the direct conversion of atmospheric water vapor into brines through high-elevation salt deliquescence&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;from &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0019103512000644#b0050&quot; rel=&quot;nofollow noreferrer&quot;&gt;Joseph Levy, Hydrological characteristics of recurrent slope lineae on Mars: Evidence for liquid flow through regolith and comparisons with Antarctic terrestrial analogs, Icarus, Volume 219, Issue 1, 2012, Pages 1-4&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This mean that this Antarctica analogue to Mars RSL have several sources of water (meltwater, shallow ground ice and atmospheric water vapor deliquescence).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Comparatively, on Mars, source for the RSL have been hypothesized to originate from snow melting, deliquescence, dry flow or shallow groundwater. &lt;a href=&quot;https://www.nature.com/articles/s41561-019-0327-5&quot; rel=&quot;nofollow noreferrer&quot;&gt;And more recently, from deep aquifers&lt;/a&gt;  through fractures (impact, tectonic) such as shown in this study at Palikir Crater inside Newton Crater Basin and Triolet Crater. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nevertheless, there is entire sessions at the Lunar and Planetary Science Conference dedicated at Martian Brines (&lt;a href=&quot;https://www.hou.usra.edu/meetings/lpsc2019/pdf/lpsc2019_program.htm#sess252&quot; rel=&quot;nofollow noreferrer&quot;&gt;MARTIAN BRINES:  OLD SALTS AND NEW VIEWS&lt;/a&gt;) and RSL or actual slope processes (&lt;a href=&quot;https://www.hou.usra.edu/meetings/lpsc2019/pdf/lpsc2019_program.htm#sess333&quot; rel=&quot;nofollow noreferrer&quot;&gt;THING FALL DOWN GO BOOM:  MARS DOWNSLOPE MOTION&lt;/a&gt;). While models are getting better and more elaborated, there is still opposing views and this dynamic field of study is moving very rapidly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, life found in brine on earth are halophiles, a type of extremophiles - but this is a whole topic in itself.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2019-05-25T20:17:23.713" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17048" PostTypeId="1" CreationDate="2019-05-26T09:20:42.093" Score="10" ViewCount="2045" Body="&lt;p&gt;By heat and pressure, both coal and oil can produce gas. But what is the most important substance for gas? Is there a relation to the amounts of marine organism (sea life) which died and the amount of plants and trees which was covered by sand or is oil (sea life) or coal (plants) just more capable of producing gas?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Else what is the alternative contributing source?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="6129" LastEditDate="2020-05-08T08:31:40.003" LastActivityDate="2021-06-23T15:47:46.280" Title="What is the most important source of natural gas? Coal, oil or other?" Tags="|gas|petroleum|fossil-fuel|coal|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="17049" PostTypeId="2" ParentId="17048" CreationDate="2019-05-26T10:37:09.750" Score="16" Body="&lt;p&gt;The most important source of natural gas is natural gas. This is why it is called natural. It is not &quot;made&quot; from oil or coal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Natural gas forms by decomposition of organic material. Whether the organic material decomposes to coal, oil, or gas depends on the composition of the original material, time, pressure, and temperature. In theory, oil (=long chains of hydrocarbons) can decompose to gas (=mostly methane and small amounts of very short chains of hydrocarbons). I am not certain as to how much of the natural gas in existence went through this oil-like stage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Coal cannot &quot;become&quot; natural hydrocarbon gas, because it contains no hydrogen. It can be burnt to form carbon dioxide, which is a gas, but this is not what you're talking about.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-05-26T10:37:09.750" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17050" PostTypeId="2" ParentId="17041" CreationDate="2019-05-26T10:43:40.920" Score="0" Body="&lt;p&gt;These positions are pretty much all on a volunteer basis. There are no scientists who are paid directly for this. This is just part of a scientist's job. Things as fun and lucrative as this are usually competitive, which means you have to apply and demonstrate that you are better than other candidates. Since this is what you already did, I don't see what else you can do.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-05-26T10:43:40.920" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17052" PostTypeId="2" ParentId="17048" CreationDate="2019-05-26T13:34:08.280" Score="5" Body="&lt;p&gt;A significant part of the natural gas used around the world today comes from oil fields.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On top of the oil is a layer of natural gas, and in the crude oil is dissolved natural gas. This will be released when the pressure drops during the extraction of the crude oil so the natural gas will be separated from the oil during the extraction process.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earlier this gas was flared (burned off) during extraction, but this is no longer alowed for many oil fields to do so the natural gas is now collected and processed before the gas is sold to users around the globe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Link to pictures of flaring around the world &lt;a href=&quot;https://geology.com/articles/oil-fields-from-space/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://geology.com/articles/oil-fields-from-space/&lt;/a&gt; A lot of work remains to limit the flaring from oil and gas fields,Some flaring is to avoid over pressure for safety reasons and is unavoidable.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6258" LastEditDate="2019-05-27T18:37:46.987" LastActivityDate="2019-05-27T18:37:46.987" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17053" PostTypeId="2" ParentId="14397" CreationDate="2019-05-26T16:02:54.053" Score="4" Body="&lt;p&gt;The temperature would stabilize to a steady temperature when you go down 15 ft or so.  The point where it gets significantly warmer is probably much deeper than you want to go.&#xA;   A better system would probably be to bury two separate loops that are 6 or 8 ft deep.  One is the heat loop on one side of the house and the second could be the cool loop on the other side of the house.  In the winter, cool the ground down with outside air.  this should freeze the ground in the cold loop.  In the summer, use the cool frozen loop to connect to your house instead of the outside air.&#xA;   The opposite is done with the heat loop on the other side of the house. Heat the ground all summer with outside air.  You could even have a solar powered fan blow hot air through a solar collector then underground.  In the winter, close the outside connection and hook it up to blow through a closed loop that draws the stored heat from the ground to your basement all winter.&#xA;   I don't really have any university studies to back up what I am saying.  It just makes common sense.&lt;/p&gt;&#xA;" OwnerUserId="16980" LastActivityDate="2019-05-26T16:02:54.053" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17054" PostTypeId="2" ParentId="8267" CreationDate="2019-05-26T16:28:25.277" Score="0" Body="&lt;p&gt;I used to find many of them in gray shale limestone rocks on the lakes hore in the North East USA. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a kid we were told that they were called &quot;lucky stones&quot;.  It was lucky if we found one.  We were told that the Native Americans used to find them and use them for weighting down the bottom of their fishing nets. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I always assumed that an ancient water plant had grown in the mud and over the millions of years, the plant deteriorated and left a fossil.  Over time, the plant fossil got destroyed and left a hole where the plant had been.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some times we would find small pieces of underwater plant fossils on the shore also. Sometimes we would find plant fossils in a shale rock cliffs as the shale breaks away.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/GD2z2.jpg&quot; alt=&quot;enter image description here&quot;&gt;!&lt;/p&gt;&#xA;" OwnerUserId="16980" LastEditorUserId="2470" LastEditDate="2020-01-25T05:59:12.177" LastActivityDate="2020-01-25T05:59:12.177" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17055" PostTypeId="1" CreationDate="2019-05-26T17:24:03.753" Score="0" ViewCount="224" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/WNPeB.jpg&quot; alt=&quot;enter image description here&quot;&gt; If I already had a crew that built a pipe line in california from the ocean to the sahara how long would it take to wet the dry lands with rain water and what kind of weather or cliamate change would accur would the changes be good for southern california. There is mass drout in california which spring and winter would last longer putting a change on climate?  This would be man made accept for the natural percipitation that would accur in the desert bringing maore rain and clouds and possible thunder and lighting storms could this as it is already patended a bigger and better climate change?&lt;/p&gt;&#xA;" OwnerUserId="16982" LastActivityDate="2019-05-27T03:41:22.053" Title="A pipeline from the ocean to the desert causing a climate change for a drout in california a good idea?" Tags="|water|" AnswerCount="1" CommentCount="3" ClosedDate="2019-05-27T15:52:59.353" ContentLicense="CC BY-SA 4.0" />
  <row Id="17056" PostTypeId="2" ParentId="17048" CreationDate="2019-05-26T19:20:53.517" Score="2" Body="&lt;p&gt;The most important factor for petroleum becoming gas isn't a substance, it's temperature and pressure. Most reservoirs have varying degrees of both; the T&amp;amp;P dictates how much of each will form. Knowing the type of field tells you what you should expect, be it a natural reservoir (black gold), or peat bogs (oil sands).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Geologists often refer to the temperature range in which oil forms as an &quot;oil window&quot;. Below the minimum temperature oil remains trapped in the form of kerogen. Above the maximum temperature the oil is converted to natural gas through the process of thermal cracking. Sometimes, oil formed at extreme depths may migrate and become trapped at a much shallower level. The Athabasca Oil Sands are one example of this. – &lt;a href=&quot;https://en.wikipedia.org/wiki/Petroleum&quot; rel=&quot;nofollow noreferrer&quot;&gt;Petroleum&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The oil in Texas, where 40% of America's crude comes from, is under a caprock, which traps a &quot;three-layer cake with a layer of water below the oil layer and a layer of gas above it&quot; &lt;a href=&quot;https://en.wikipedia.org/wiki/Petroleum&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Wiki)&lt;/a&gt;. This type of reservoir will contain much natural gas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The oil sands of Canada, which has the largest mining operation by area in the entire world, extracts bitumen; aka: peat. To extract natural gas from oil sand it must be cracked, which costs money, as opposed to the freely available stuff under a capstone.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Peat&quot; rel=&quot;nofollow noreferrer&quot;&gt;Peat&lt;/a&gt; forms in wetland conditions [terrestrial life, not aquatic], where flooding or stagnant water obstructs the flow of oxygen from the atmosphere, slowing the rate of decomposition.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A fossil fuel, &lt;a href=&quot;https://en.wikipedia.org/wiki/Petroleum&quot; rel=&quot;nofollow noreferrer&quot;&gt;petroleum&lt;/a&gt; is formed when large quantities of dead organisms, mostly zooplankton and algae [aquatic life], are buried underneath sedimentary rock and subjected to both intense heat and pressure. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;TL;DR:&lt;/strong&gt; the good stuff comes from poorly decomposed aquatic life. The harder stuff comes from poorly decomposed plant life.... Apparently the dinosaurs &lt;em&gt;did not&lt;/em&gt; all die and turn into oil.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Apologies but, &lt;em&gt;the most important source&lt;/em&gt; IMO would need to be determined by computing the amount of barrels produced, while knowing what type of field they came from. E.g., &quot;Oil sands were the source of 62% of Alberta's total oil production and 47% of all oil produced in Canada.&quot; (&lt;a href=&quot;https://en.wikipedia.org/wiki/Athabasca_oil_sands&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wiki&lt;/a&gt;) Now you just have to figure out how many barrels Canada produces, contrasted against the same information for every country or oil company throughout the entire world.&lt;/p&gt;&#xA;" OwnerUserId="654" LastEditorUserId="654" LastEditDate="2019-05-27T00:29:43.107" LastActivityDate="2019-05-27T00:29:43.107" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17059" PostTypeId="2" ParentId="17033" CreationDate="2019-05-27T02:47:03.503" Score="0" Body="&lt;p&gt;I would say they both require having rock over top of the water - so not just a water passage between two cliffs. For land caves, the distinction between a cave, a rock shelter, and an overhang generally depends on whether you can in get beyond view of the entrance, but for sea caves, that generally isn't how they are named. But to be considered a cave you would have to be able to enter and it should be longer than it is wide. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;An arch will have an opening to daylight on both sides of the arch. A sea cave will have a dead end. There are many cases in conventional caves where there are multiple entrances but I think that is exceedingly rare in erosional sea caves. Some of the distinction then could be just semantics and how someone decided to name it. If it were to occur, the distinction would probably be made on the distance between the entrances - can you see daylight from the other entrance, &lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2019-05-27T02:47:03.503" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17060" PostTypeId="2" ParentId="17055" CreationDate="2019-05-27T03:41:22.053" Score="2" Body="&lt;p&gt;It's been proposed. Not for California, but for the Sahara, and the Empty Quarter in Arabia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The notion is that you are creating an interior salt sea -- the equivalent of Great Salt lake.  Evaporation from that sea modifieds the local climate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You have to move a LOT of water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Done right,you can process the resulting salt for other products.  Bromine, Chlorine, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A more interesting idea is to use this to MAKE power.  &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Build a 10 km diameter greenhouse.&lt;/li&gt;&#xA;&lt;li&gt;Build a 2 or more kilometer high chimney.&lt;/li&gt;&#xA;&lt;li&gt;The outer part of the green house is floored with ponds of water with carbon suspended in the water.  Essentially dilute india ink.&lt;/li&gt;&#xA;&lt;li&gt;At the base of the chimney you have wind turbines.&lt;/li&gt;&#xA;&lt;li&gt;As air enters the green house it picks up heat and moisture.  The moist air in the chimney rises, drawing more air in.  As it rises it cools, water condenses, adding heat back into the system.  In effect you have a single updraft from a thunders storm.&lt;/li&gt;&#xA;&lt;li&gt;Done right, the water starts to rain out part way up.  You can collect the water as fresh water.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="13145" LastActivityDate="2019-05-27T03:41:22.053" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17062" PostTypeId="1" CreationDate="2019-05-27T12:50:36.327" Score="1" ViewCount="61" Body="&lt;p&gt;I think I understand the mechanism of water vapor feedback in climate change pretty well: a (theoretical) temperature increase due to some isolated factor (e.g. increase in &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; concentration) causes a shift in water vapor saturation density and an additional evaporation rate. The consequential shift in actual water vapor concentration causes additional absorption together with isotropic re-emission, slowing down the radiation transport. So the theoretical temperature rise &lt;span class=&quot;math-container&quot;&gt;$\Delta T_{nofb}$&lt;/span&gt; without consideration of feedback is &quot;amplified&quot; by some factor &lt;span class=&quot;math-container&quot;&gt;$\beta$&lt;/span&gt;, giving the real temperature rise, with feedback&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\Delta T_{wfb} = \beta \Delta T_{nofb}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course I know that this argument has to be replaced by solving a differential equation in a more rigorous treatment. There is no &quot;before&quot; and &quot;after&quot;, there is only the combined effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;But what if we consider the &quot;theoretical&quot; temperature change due to the change in solar irradiation from orbital eccentricity? Shouldn't this be amplified by the same water vapor feedback mechanism as well?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Solar irradiation varies over the year between &lt;span class=&quot;math-container&quot;&gt;$1310$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$W/m^2$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$1420$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$W/m^2$&lt;/span&gt;. According to Stefan-Boltzmann's Law in differential form we would have a heating of the ground by direct absorption of sunlight &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\frac{dP}{P}=4 \frac{dT}{T}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;or&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\frac{\Delta P}{P}\approx 4 \frac{\Delta T}{T}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I would expect the temperature change due to yearly changes in solar irradiation (but without the effect of water vapor feedback) to be about&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\Delta T \approx \frac{T}{4} \frac{\Delta P}{P} = \frac{290 K}{4} \frac{90 W/m^2 }{1366 W/m^2}\approx 4.8 K$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The favorite answer to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/11913/does-the-elliptical-orbit-of-the-earth-have-effect-on-earths-climate&quot;&gt;this question&lt;/a&gt; shows a plot that seems to indicate that the order of magnitude is indeed like that, the global line shows a variation of about &lt;span class=&quot;math-container&quot;&gt;$3.8$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$K$&lt;/span&gt;. I don't know if this was derived from measurements, but I assume that it is somehow substantiated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But if we now adopt the assumption that these ~5 Kelvin get amplified by the water vapor feedback as well, and take into account that this amplification is said to be in the order of magnitude ~2 in the context of &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; entry by mankind, I would expect the amplified yearly temperature change due to the orbital eccentricity of earth to be &lt;span class=&quot;math-container&quot;&gt;$~10$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$K$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the linked answer wrong, or is there some flaw in the argument?&lt;/p&gt;&#xA;" OwnerUserId="12784" LastEditorUserId="12784" LastEditDate="2019-05-27T18:29:53.110" LastActivityDate="2019-05-27T18:29:53.110" Title="Yearly changes of solar irradiation and atmospheric feedback" Tags="|climate-change|water-vapour|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17063" PostTypeId="2" ParentId="17062" CreationDate="2019-05-27T13:39:57.320" Score="1" Body="&lt;p&gt;I think your ~2 figure for CO2 greenhouse amplification is in error. &#xA;* In the last 200 years it's gone from the high 280s to low 400s.  This is an increase of about 50%  Good thing it's not linear as the previous greenhouse effect is overall about 18K.  If there was no effect, the earth would average about 0 C.&#xA;* As CO2 increases it takes more bounces for an infrared photon to escape.  But you get some degree of diminishing returns.  Doubling the CO2 doesn't double the greenhouse effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But to your question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Right now we have about 1 degree of additional greenhouse effect.  Compared to the 18 degrees of existing greenhouse effect this is about 5%.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would expect that this is the factor to use.  So the eccentricity amplification should be about 5%  So 5.25K instead of 5.  or observationally 1.05 * 3.8K &lt;/p&gt;&#xA;" OwnerUserId="13145" LastActivityDate="2019-05-27T13:39:57.320" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17064" PostTypeId="2" ParentId="17041" CreationDate="2019-05-27T13:57:09.963" Score="2" Body="&lt;p&gt;Try the long game:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Start reading up on the research that is being done.  For the interesting ones, start corresponding with the authors asking questions about the work.  They have to be good questions, showing that you know what you are talking about.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Look at who funds each researcher.  Check the papers for those 'thank-yous' that give credit to various individuals and institutions.  Check the institutions to see how they hire support personnel.  If you can't get a job as a researcher, look at getting a job just as a tech.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Most researchers are connected with one more more institutions.  Some of these specialize in polar science.  Some may supply support crews that span scientific disciplines.  E.g. They may have a pool of snow-cat operators that any of the scientists can draw upon to move equipment and personnel.  This is more likely with the permanent bases.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Can you speak well?  Do you have a large grasp of polar science in many fields?  Look at being a guide on the cruise boats that go to the arctic.  If you are quick witted, and can reduce difficult topics to digestible chunks, this is a possibility.  Train for it by writing a science blog.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Write a polar science blog.  Turn dry science into good clear interesting commentary about what's happing, how it happens, why it's important.  This becomes something to put on your resume, and if you get a decent following may itself get you there as a science journalist.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Prepare yourself. Learn how to dress and take care of yourself in Arctic regions.  Someone they don't have to train as much is cheaper for them.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Consider having your appendix removed.  At one point this was recommended as an appendectomy in Antarctica is double plus un-fun.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="13145" LastActivityDate="2019-05-27T13:57:09.963" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17065" PostTypeId="2" ParentId="17028" CreationDate="2019-05-27T14:09:19.350" Score="0" Body="&lt;p&gt;The abrupt rise then slower decay argues for some sort of tipping point event.  While the Milhankovich cycles may be the driving force, they are to first approximation sinusoidal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One candidate for this could be a methane pulse.  E.g. you get warm enough to thaw the arctic permafrost, and while the heat seeps in you get a continuous source of methane.  If ocean temps get warm enough clathrate methane is released.  This is happening off of the north Siberian coast now.  Magnitude of this is up in the air, but the potential for gigatons is there.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't think that methane by itself has a long enough residence time, but once past a threshold, it may trigger further releases in a rapid positive feedback loop.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the Milhankovich cycle warms the arctic a bit.  Passes a tipping point, methane is released starting a feedback loop releasing more and more methane, warming the earth rapidly by 10 degrees.  Methane release tapers off as the heat has to soak in deeper and deeper to be effective at further releases.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you wanted to check this, check the phase of the Milhankovich forcing to the temperature.  This notion is more plausible if there is substantial forcing for the northern hemisphere before the temperature spike occurs.&lt;/p&gt;&#xA;" OwnerUserId="13145" LastActivityDate="2019-05-27T14:09:19.350" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17066" PostTypeId="1" CreationDate="2019-05-27T19:01:22.923" Score="0" ViewCount="50" Body="&lt;p&gt;I'm making a science project to protect the crops from wind lodging by placing some shields beside the field only when needed (wind have beneficial effects on crops). I want to use some sensors like anemometer to measure the wind velocity and direction to detect whether protection shield is needed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I can't figure out where to find the information that what is the minimum velocity of air to lodge crops. I know it will depend on which type of crop we're cultivating e.g. rice, jute, corn etc. I want to use just any one of these to demonstrate in my science project.&lt;/p&gt;&#xA;" OwnerUserId="16984" LastEditorUserId="16984" LastEditDate="2019-05-29T03:53:24.583" LastActivityDate="2019-05-29T03:53:24.583" Title="How strong wind is needed for crop lodging?" Tags="|agriculture|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17071" PostTypeId="2" ParentId="8446" CreationDate="2019-05-28T18:31:14.747" Score="1" Body="&lt;p&gt;Compare your descriptions of the two climates:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In the summer here [Minnesota] it always reaches temperatures in the 90s (F) for&#xA;  periods of time but not every week. The humidity is often high and the&#xA;  dew point often tropical.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;[In Guangdong] It is usually in the 90s during the summer instead of&#xA;  sometimes. It is always humid and feels tropical.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You're saying that sometimes Minnesota is as hot as Guangdong usually is.&#xA;Thus (based only on this info) Guangdong probably has a higher mean temperature.&#xA;Assuming there is some variability around that mean, it seems likely that Guangdong also has a higher maximum temperature. Thus, Guangdong might be perceived as hotter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cultural factors might also contribute to the perception of difference, such as the type of clothing worn, the prevalence of air conditioning, or the activities that the people in question are typically undertaking in each place.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-05-28T18:31:14.747" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17073" PostTypeId="1" CreationDate="2019-05-28T19:26:26.423" Score="3" ViewCount="118" Body="&lt;ul&gt;&#xA;&lt;li&gt;You can take up way less square footage for the same amount of production&lt;/li&gt;&#xA;&lt;li&gt;You can eliminate the need for pesticides&lt;/li&gt;&#xA;&lt;li&gt;You can power the farms from renewable energy&lt;/li&gt;&#xA;&lt;li&gt;You can significantly increase growing efficiency &lt;/li&gt;&#xA;&lt;li&gt;You can significantly increase the nutritional value of plants&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I see major opportunity in vertical farming due to these reasons. What do you guys think? Will we see vertical farming taking over the agricultural industry?&lt;/p&gt;&#xA;" OwnerUserId="16992" LastActivityDate="2019-05-29T09:29:58.490" Title="Is there major potential for vertical farming?" Tags="|agriculture|technology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17077" PostTypeId="2" ParentId="14472" CreationDate="2019-05-28T22:31:20.700" Score="-3" Body="&lt;p&gt;It looks very much like a shark tooth, but it looks like it’s weathered and worn. It may have spent a good deal of time buried below the sand, being slowly ground by the sand and tide action. Eventually it became dislodged and after a while of being worn smoother it washed up and you found it.&lt;/p&gt;&#xA;" OwnerUserId="16993" LastEditorUserId="595" LastEditDate="2019-05-29T09:48:48.773" LastActivityDate="2019-05-29T09:48:48.773" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17078" PostTypeId="1" CreationDate="2019-05-29T05:01:52.993" Score="1" ViewCount="635" Body="&lt;p&gt;Observe the vertical green lines in this diagram:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/hsBAB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hsBAB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;Those events shows when temperature starts to sink when radiance is at top or even before that. If there was a simple connection between radiance and temperature the temperature should start to sink after radiance maximum.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What climatic mechanisms could start a global cooling when the&#xA;  radiance is maximal or heading to maximal, due to the Milankovitch&#xA;  cycles? Could it be a drastic increase of convection?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Constructive answers will be rewarded with bounties&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="16809" LastEditorUserId="1411" LastEditDate="2019-05-30T12:54:10.623" LastActivityDate="2019-05-30T12:54:10.623" Title="Milankovitch cycles and what?" Tags="|climate-change|glaciation|convection|milankovitch-cycles|global-weirding|" AnswerCount="0" CommentCount="13" ContentLicense="CC BY-SA 4.0" />
  <row Id="17079" PostTypeId="2" ParentId="17073" CreationDate="2019-05-29T06:02:37.990" Score="2" Body="&lt;p&gt;As our planet gets warmer less area will be avaliable for farming so vertical farming will be needed to supply food for a growing population.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Vertical farming will not replace traditional farming but it will be an addition to this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Vertical farming can be effective in growing food by using less energy,We can use only the part of the light spectrum that plants need(UV-Blue-Red-IR)And avoid producing un needed green light(plants do not use the green part of the spectrum).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The use of water can be a lot lower in vertical farming as any evaporated water can be captured and recycled.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The need of plant nutrients can be reduced significantly,One only needs to add the nutrients the plants remove(so no runoff of nutrients at all).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The use of pesticides can be close to eliminated and this is good news for insects that are needed in the production of food and for the consumers of the food.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A very large part of the water used in prossesing of the product can be recycled and used to create more food,So less water will be wasted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A lot of the organic waste can be used as animal feed directly(Roots stems and flowers material not usable for human consumption).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the answer to your question is yes there is potential in doing this,How large potential there realy is i do not know but i think it might be significant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The prosess uses more CO2 than it releases(if renewable energy is used) so it is cleaner for the environment,It can be done anywhere so less emission of CO2 during transport to the consumers.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6258" LastEditDate="2019-05-29T09:29:58.490" LastActivityDate="2019-05-29T09:29:58.490" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17081" PostTypeId="1" AcceptedAnswerId="17084" CreationDate="2019-05-29T13:25:21.653" Score="3" ViewCount="207" Body="&lt;p&gt;I was wondering about the &lt;a href=&quot;https://physics.stackexchange.com/questions/483106/database-of-color-emissions&quot;&gt;physics of color&lt;/a&gt;, and now am interested in finding out if there are any resources (databases, text files, html tables, or pdf listings) of minerals and their associated colors or (ideally) color wavelength spectrum.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, amethyst might have a white, silver, and purple color spectrum. Onyx might have a grey, blue, or black color spectrum. Granite another spectrum. Wondering (a) if any of this information is captured in any form on the web (such as 1 journal article per mineral/rock type), and (b) if it is aggregated into a database, text file, table, or other sort of list which includes lots of types, so it would say the wavelength of visible light that it emits, or some ranges of it, or even a hex color range.&lt;/p&gt;&#xA;" OwnerUserId="16998" LastActivityDate="2019-05-29T19:24:03.940" Title="Database of color wavelengths of minerals" Tags="|mineralogy|light|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17084" PostTypeId="2" ParentId="17081" CreationDate="2019-05-29T15:26:52.623" Score="1" Body="&lt;p&gt;This type of information is made available through the &lt;a href=&quot;https://www.usgs.gov/labs/spec-lab&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS Spectroscopy Lab&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a &lt;a href=&quot;https://crustal.usgs.gov/speclab/QueryAll07a.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;researchable database&lt;/a&gt; of their current spectral library with the appropriate information for each mineral signature (formula, sample_id, type and more). Here is an example of the signature for Hematite:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yhJCC.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yhJCC.gif&quot; alt=&quot;splib07a Hematite&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further, there is an up to date publication accompanying the database titled USGS Spectral Library Version 7, available &lt;a href=&quot;https://pubs.er.usgs.gov/publication/ds1035&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2019-05-29T15:26:52.623" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17085" PostTypeId="1" AcceptedAnswerId="17194" CreationDate="2019-05-29T16:00:06.963" Score="1" ViewCount="264" Body="&lt;p&gt;Where does the chloride ions that are required for the salty taste of sea water come from ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that it is the weathering caused by the slightly acidic (due to dissolution of CO2 with water) rain that dissolves minerals in the water which gets carried to ocean. But the sodium ions/atoms require chloride ions/atoms for the salty taste. But I don't think chloride would be present in the rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please explain.&lt;/p&gt;&#xA;" OwnerUserId="17002" LastActivityDate="2019-06-14T13:11:07.903" Title="Chloride ions for the salty seawater" Tags="|rocks|minerals|rain|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17087" PostTypeId="2" ParentId="15251" CreationDate="2019-05-29T18:26:00.963" Score="1" Body="&lt;p&gt;First, based on the ONI, there are El Niño and La Niña periods, not necessarily years. For example, 2016 was El Niño during the first half and La Niña during the second half. On the flip side, From summer 1998 to early 2001 was one continuous La Niña period. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second, The The wording that the NOAA gives for official classification of El Niño and La Niña periods is a bit misleading. El Niño periods are designated as such when there are 5 consecutive three-month-running means of sea surface temperatures that are 0.5 degrees C above the 30 year mean. For example, take a look at NOAA's ONI data here: &lt;a href=&quot;https://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php&lt;/a&gt;&#xA;in 2016 there was an La Niña event that lasted from July to January because there were 5 three-month-running means in a row that were 0.5 degrees C below the 30 year mean. However, this only encompasses three &quot;season&quot;, summer, fall, and winter. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Third, to answer your question, El Niño/La Niña classification is not bound by a calendar year, so going forwards and backwards until you hit a three-month-running mean that is less than the 0.5 threshold. The NOAA has already down the work for you, and even color coded it for you at the link above. Hope this helps.&lt;/p&gt;&#xA;" OwnerUserId="17003" LastActivityDate="2019-05-29T18:26:00.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17088" PostTypeId="2" ParentId="13149" CreationDate="2019-05-29T18:28:36.590" Score="2" Body="&lt;p&gt;In Canada there is definitely a rasputitsa period, though it does not occur everywhere or necessarily in the fall, and it is not considered a rasputitsa by name.  Every spring in most parts of Canada there is a period of time when many of the soils are saturated with water from the recent snow melt.  The various forest services and companies will often close roads or reduce the load limit during the spring thaw specifically because the roadbeds are saturated to the point that large equipment can punch out the roads and if bad enough get stuck.  Even the major highways in parts of the western prairies and in many mountainous areas have reduced load limits just after spring melt because of issues with the roadbed being saturated.  This issue mainly affects the tertiary road systems because modern road construction methods are developed to reduce the effect of the spring thaw on the stability of the roads.  The post &lt;a href=&quot;https://www.canadacartage.com/canadian-spring-thaw-regulations-penalties-practices/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; describes the highway load reductions.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2019-05-29T18:28:36.590" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17089" PostTypeId="1" AcceptedAnswerId="17095" CreationDate="2019-05-29T18:49:32.480" Score="3" ViewCount="267" Body="&lt;p&gt;I asked this in the chat and it was suggested I ask on the main site.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's been a seemingly perpetual severe weather outbreak over the central and eastern U.S. over the past two weeks. Killer EF3s in Jefferson City, MO, Dayton, OH, and El Reno; flash flooding in Oklahoma; severe storms in Illinois/the Ohio Valley/Mid Atlantic; the tornadic supercells in northern NJ/Staten Island, the list goes on, and on, and on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On top of this, the southeastern U.S. is seeing record high temperatures (earliest-ever triple digit temps for Alabama) and a heat wave is currently (as of today, Wednesday 5/29) smothering the east coast. What has been the synoptic and mesoscale (fronts, upper-air) setup that can explain this unusual pattern? &lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2019-06-14T05:12:51.480" Title="What is the synoptic/atmospheric setup that is causing the U.S. severe weather outbreak in May 2019?" Tags="|meteorology|atmosphere-modelling|tornado|severe-weather|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17091" PostTypeId="2" ParentId="17085" CreationDate="2019-05-29T19:17:27.860" Score="4" Body="&lt;p&gt;Chlorine is a very reactive element. Contrary to your statement, chlorine occurs in many rocks and &lt;a href=&quot;http://webmineral.com/chem/Chem-Cl.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;minerals&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mineral &lt;a href=&quot;https://chlorine.americanchemistry.com/Science-Center/Chlorine-Compound-of-the-Month-Library/The-Mineral-Apatite-A-Natural-Source-of-Chlorine/&quot; rel=&quot;nofollow noreferrer&quot;&gt;apatite&lt;/a&gt;, with the composition: Ca5(PO4)3(F,Cl,OH), is a natural source of chlorine. Virtually all rocks contain chlorine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Chlorine even occurs occurs in &lt;a href=&quot;https://faculty.uml.edu/Nelson_Eby/Research/F&amp;amp;Cl/FCl.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;alkaline magmas&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the most common minerals containing chlorine is common salt, which is sodium chloride, NaCl.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geologically, chlorine is everywhere. When rocks are exposed to water and acids minerals, including chlorine, dissolve into solution and they are transported to lakes, salt lakes, aquifers and oceans.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2019-06-14T12:46:49.503" LastActivityDate="2019-06-14T12:46:49.503" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17092" PostTypeId="2" ParentId="17081" CreationDate="2019-05-29T19:24:03.940" Score="1" Body="&lt;p&gt;Another online database to try is &lt;a href=&quot;http://www.webmineral.com/help/Color.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one&lt;/a&gt;, which lists minerals for various colors&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-05-29T19:24:03.940" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17095" PostTypeId="2" ParentId="17089" CreationDate="2019-05-30T05:48:12.293" Score="7" Body="&lt;p&gt;Summarizing the comments I made above in this question and in this one - &lt;a href=&quot;https://earthscience.stackexchange.com/questions/16942/does-this-weather-pattern-have-a-name?noredirect=1&amp;amp;lq=1&quot;&gt;Does this weather pattern have a name ?&lt;/a&gt; I believe significant parts of the US  are experiencing a  &lt;a href=&quot;https://en.wikipedia.org/wiki/Stationary_front&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stationary Front&lt;/a&gt; for the past one month. There has been plenty of media coverage of this event and if you google the term &quot;stationary front&quot; under news one will receive a lot of links to the TV news media with meteorologists giving detailed analysis of this event. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A few summarized below - &lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) &lt;a href=&quot;https://www.sentinelsource.com/news/local/week-s-bleak-weather-not-an-unusual-spring-occurrence/article_b33c5789-fd12-530b-b3d2-73a5dd17da7a.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Week's bleak weather not an unusual spring occurrence &lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2)&lt;a href=&quot;https://www.wthitv.com/content/video/510553662.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;A stationary front is stuck across the middle parts of Illinois and Indiana&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will attempt to provide a synoptic scale explanation of the event from reanalysis data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) From JMA's site  - &lt;a href=&quot;https://i.stack.imgur.com/UzjyZ.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UzjyZ.gif&quot; alt=&quot;wave activity flux derived from stream function from April 29th through May 28th 2019&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;an upper level look at the 200 hPa surface reveals that an equatorward trajectory of the wave activity flux vector(seen as small arrows) is seen  from the Upper North Pacific. Climatologically Rossby Wave Breaking can occur from boreal fall to boreal spring. The signal is seen at 30 day , &lt;a href=&quot;https://ds.data.jma.go.jp/tcc/tcc/products/clisys/anim/GIF/tp/hist/2019/05/29/10day/OlrPsiWaf_tp200hPa_20190529.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;10 day period&lt;/a&gt; and &lt;a href=&quot;https://ds.data.jma.go.jp/tcc/tcc/products/clisys/anim/GIF/tp/hist/2019/05/29/7day/OlrPsiWaf_tp200hPa_20190529.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;7 day period&lt;/a&gt; and &lt;a href=&quot;https://ds.data.jma.go.jp/tcc/tcc/products/clisys/anim/GIF/tp/hist/2019/05/29/5day/OlrPsiWaf_tp200hPa_20190529.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;5 day period&lt;/a&gt;. The signal is present in the raw data as well as in the &lt;a href=&quot;https://ds.data.jma.go.jp/tcc/tcc/products/clisys/anim/GIF/tp/anom/2019/05/29/30day/OlrPsiWaf_tp200hPa_20190529.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;anomaly&lt;/a&gt;. Most importantly this wave activity flux is directed towards the continental USA all the way from New Mexico to the Great Lakes region. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A popular science version of the above information has been discussed over at this link - &lt;a href=&quot;http://blogs.discovermagazine.com/imageo/2019/05/24/whats-up-with-all-this-wild-weird-weather-and-is-it-linked-to-climate-change/#.XO9zFyZS_M0&quot; rel=&quot;nofollow noreferrer&quot;&gt;What's up with all this wet weird weather ?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) At the surface level this &quot;stationary front&quot; presents itself as air masses of two different temperatures as seen from this plot and one can see the frontal boundary more or less coincides with the rising contour of the stream function plot in (1). Here the south easterlies are bringing in warm moist air from the Gulf coast and the Atlantic and the colder air masses are coming from Canada and North East Pacific. So the key question is whether the upper level influence is directing the surface level weather and that question can be answered by calculating PV anomalies when ERA 5 reanalysis data does become available. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FbwA3.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FbwA3.gif&quot; alt=&quot;Surface Air Temperature And 10 m wind anomaly&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source - &lt;a href=&quot;https://ds.data.jma.go.jp/tcc/tcc/products/clisys/anim/anim_tp.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;JMA reanalysis data&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) The moisture flux being pumped into the south eastern part of the USA can be seen from this plot over a seven day period - &lt;a href=&quot;https://i.stack.imgur.com/Ud82u.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ud82u.gif&quot; alt=&quot;Moisture Flux for North America 7 day mean&quot;&gt;&lt;/a&gt;.&#xA;Again the signal is present over 30 day period, 10 day period and 3 day period and over a 1 day period. I would like to point out the moisture flux is seen at different levels of the atmosphere from surface level to the 300 hPa surface. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source - &lt;a href=&quot;https://www.esrl.noaa.gov/psd/data/composites/nssl/day/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCAR NOAA reanalysis derived variables&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;4) Last year (2018) apparently a &lt;a href=&quot;https://en.wikipedia.org/wiki/Zonal_wavenumber&quot; rel=&quot;nofollow noreferrer&quot;&gt;wavenumber&lt;/a&gt; - 7 was found to be causing weather stalls as shown in this link - &lt;a href=&quot;https://physicsworld.com/a/summer-weather-extremes-linked-to-stalled-rossby-waves-in-the-jet-stream/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weather stalls becoming longer&lt;/a&gt;. This year in April  it is a wavenumber 5 pattern as seen in this site - &lt;a href=&quot;https://seekingalpha.com/article/4255613-natural-gas-week-ahead-mild-warm-weather-pattern-encompass-large-part-country-injection&quot; rel=&quot;nofollow noreferrer&quot;&gt;Current Weather reports&lt;/a&gt; and summarized here&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;From a global point of view, the weather pattern in the beginning parts of the 6-10 day (around day 7) will enter into a wavenumber 5 pattern. That's where you have 5 distinct upper-level troughs (areas where the weather is cool and stormy) around the globe. It's like a major traffic jam in the atmosphere and could lead to weather stagnation with little to no variation for days and/or weeks. This could also lead to extreme weather events such as droughts and severe weather/flooding across some parts of the world.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and I am able to pick up the wavenumber 5 or &lt;a href=&quot;https://twitter.com/rahmstorf/status/1133834691826638848&quot; rel=&quot;nofollow noreferrer&quot;&gt;6 as pointed by user Deditos&lt;/a&gt; (as well in this twitter feed - &lt;a href=&quot;https://twitter.com/KKornhuber/status/1136027676152619008&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wave number 6 planetary wave&lt;/a&gt;) from NCAR NOAA reanalysis data for the 500 hPa geopotential height anomaly for the month of May.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/qVlVS.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qVlVS.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-06-14T05:12:51.480" LastActivityDate="2019-06-14T05:12:51.480" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17097" PostTypeId="2" ParentId="17042" CreationDate="2019-05-30T13:38:23.223" Score="6" Body="&lt;p&gt;Carbonaceous aerosols are formed by a mixture of substances with different chemical, physical, and optical properties. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Certain organic substances are mostly transparent to sunlight and therefore do not contribute to Earth warming or cooling. Other substances are mostly reflective, therefore their presence in the atmosphere contributes to Earth's cooling. Yet there are substances that absorb sunlight thus warming the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Light absorbing carbonaceous aerosols do not form a uniform group either. They include soot particles, smoke, organic compounds such as levoglucosan and the spectre of humic substances all with different optical properties. The figure below shows schematically the absorption spectrum of two compounds representative of different groups of light absorbing materials.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/co1iK.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/co1iK.png&quot; alt=&quot;light absorption spectra of blackish and yellowish substances&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One compound labeled B1 has a more uniform distribution of absorption coefficient across the visible spectrum where the absorption coefficient at the red edge is about half of that at the blue edge. Another compound labeled B2 has a much steeper slope at the blue edge. It would have a yellowish or light brown color. Think of the yellowish fumes that can be seen when a piece of wood is ignited.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming uniform absorption spectrum for light absorbing organic carbon can lead to significant &lt;strong&gt;overestimation&lt;/strong&gt; of light absorption by atmospheric carbon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand estimating the carbon content of the atmosphere via measurements in the green or red parts of the spectrum would lead to a significant &lt;strong&gt;underestimation&lt;/strong&gt; of light absorption in the blue and ultraviolet parts of the spectrum.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To reduce the error caused by the non-uniform absorption spectrum of some of light absorbing carbon we could instead think of light absorbing carbonaceous aerosols as two separate groups namely &lt;strong&gt;Black Carbon&lt;/strong&gt; with uniform light absorption spectrum and &lt;strong&gt;Brown Carbon&lt;/strong&gt; with steep increase in light absorption towards the blue edge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In our example B1 would be assigned to Black Carbon group and B2 would be assigned to the Brown Carbon group.&lt;/p&gt;&#xA;" OwnerUserId="2511" LastEditorUserId="2511" LastEditDate="2019-05-30T14:14:25.770" LastActivityDate="2019-05-30T14:14:25.770" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17098" PostTypeId="1" AcceptedAnswerId="17242" CreationDate="2019-05-30T18:48:10.227" Score="3" ViewCount="1015" Body="&lt;p&gt;Obviously pressurized air can hold more water than regular air, so an increase in overall pressure would result in an inversely proportional decrease in relative humidity. However, I can't seem to find any equations which reflect this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically my issue is that my thermohygrometer calculates the relative humidity assuming that atmospheric pressure is 101.3kPa but where I am measuring it the pressure is about 140kPa. This can be fixed by multiplying the reading by (101.3kPa/140kPa), but I am having a hard time expressing that scientifically and mathematically.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, what is the mathematical relationship between pressure and relative humidity?&lt;/p&gt;&#xA;" OwnerUserId="17014" LastActivityDate="2019-06-21T17:27:55.833" Title="How does total pressure affect relative humidity and how do I correct my hygrometer for pressure?" Tags="|atmosphere|temperature|humidity|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17099" PostTypeId="1" CreationDate="2019-05-30T19:04:57.450" Score="2" ViewCount="324" Body="&lt;p&gt;I have a DEM as shown for which I have determined flow paths using D8 algorithm (My own code) in R. The resulting DEM with the flow paths is also shown. The flow paths are generated in the form of lines with the help of lines function in R, joining the centers of each pixel in the direction of steepest slope. I would like to perform flow routing with flow paths being derived on the DEM. It should be noted that the flow paths are just lines plotted on the DEM using lines function and elevation of the pixels. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any way to perform flow routing for a hypothetical storm event in R?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bsrLy.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bsrLy.png&quot; alt=&quot;The DEM&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/P2BEU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/P2BEU.png&quot; alt=&quot;The DEM with flow paths developed&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="17013" LastEditorUserId="1411" LastEditDate="2019-05-30T19:09:18.540" LastActivityDate="2019-06-03T17:53:46.020" Title="Code for DEM based flow routing in R" Tags="|hydrology|gis|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17104" PostTypeId="1" AcceptedAnswerId="17107" CreationDate="2019-05-30T23:04:11.260" Score="7" ViewCount="1501" Body="&lt;p&gt;If the Sun disappeared&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;How long would it take for the earth to freeze beyond excavatable&#xA;depths?&lt;/li&gt;&#xA;&lt;li&gt;How long until it freezes to the core? (Is this different than without removing the Sun?)&lt;/li&gt;&#xA;&lt;li&gt;Would we be able to live for a while by relocating downwards?&#xA;&lt;ul&gt;&#xA;&lt;li&gt;If so around what portion of the population and for how long?&lt;/li&gt;&#xA;&lt;li&gt;Could we find a way to keep some oxygen with us or to extract what would turn liquid/solid on the surface?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;Would the molten/ductile rock expand or contract?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="14561" LastEditorUserId="6016" LastEditDate="2020-10-07T14:16:31.930" LastActivityDate="2020-10-09T05:24:08.070" Title="If the Sun disappeared, how long would it take for the Earth to freeze beyond excavatable depths?" Tags="|geothermal-heat|sun|crust|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17107" PostTypeId="2" ParentId="17104" CreationDate="2019-05-31T16:38:05.377" Score="5" Body="&lt;p&gt;Step wise approach:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Right now when the surface is very cold, the frost depth here (Alberta, -40 min winter temps) can reach 8 feet.  Below about 30 feet seasonal temperature changes are under a degree.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Around depths of 100 feet temperatures start to rise, increasing about 25C/km or 1F/70 feet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First approximation then for zero solar input (effective temp -270K) would be that you would need (270+20)/25 = ~12 km of depth to have roughly room temperature conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We currently can't dig holes that deep.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The world's deepest is 3.9 km in South Africa.  Note that at 25C/km the temperature at that depth is well over boiling point.  Air is compressed at the surface, then chilled.  Air expansion in the working levels of the mine expands and cools further.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This assumes that the earth's insulation value is linear with depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now:  Time: We can put a lower bound on it:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A year's temperature variation right now reaches 30 feet, with most of that being in a fraction of that.  So suppose that it penetrates at 30 feet per year.  I think this is too much, but it serves as a bound.  At 30 feet per year it would take 33 years per thousand feet, or about 110 years per kilometer. At present depts of 3.9 km, we have about 4 centuries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In practice you wouldn't do it like this.  Go deep enough to get away from the worst, built an insulated cave, and run heat exchange tubing deeper to heat your cozy refuge until whoever borrowed the sun puts it back.&lt;/p&gt;&#xA;" OwnerUserId="13145" LastEditorUserId="13145" LastEditDate="2019-05-31T20:17:33.740" LastActivityDate="2019-05-31T20:17:33.740" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17110" PostTypeId="1" AcceptedAnswerId="17114" CreationDate="2019-05-31T19:29:22.583" Score="6" ViewCount="1109" Body="&lt;p&gt;How long does it take the magnetic field to move once the poles start to flip?&#xA;What environmentally would change? Does the core of the Earth flip?&lt;/p&gt;&#xA;&lt;p&gt;The magnetic poles are moving now. When will it start to move faster and how would a compass behave?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.space.com/43173-earth-magnetic-field-flips-when.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Is Earth's Magnetic Field Flipping Soon?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bDsCw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bDsCw.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="18088" LastEditDate="2023-03-26T00:33:22.563" LastActivityDate="2023-03-26T00:33:22.563" Title="What happens when the North and South poles flip?" Tags="|climate-change|climate|geomagnetism|time|paleomagnetism|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17114" PostTypeId="2" ParentId="17110" CreationDate="2019-06-01T05:36:59.290" Score="6" Body="&lt;p&gt;First of all I will try to explain what a geomagnetic pole reversal is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A magnetic pole reversal happens when the magnetic field weakens until it can no longer sustain itself. This can take 1000-3000 Years or more to complete the time it takes is very variable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;After years with a weak and sometimes variable magnetic field. The magnetic field re emerges in its original, or in a changed direction. So it is not the poles moving over the surface of earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Link &lt;a href=&quot;https://en.wikipedia.org/wiki/Geomagnetic_reversal&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Geomagnetic_reversal&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What happens during a geomagnetic pole reversal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During a pole reversal earths magnetic field is weak so our planet is less protected from cosmic radiation and from the solar wind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Link &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_magnetic_field&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Earth%27s_magnetic_field&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This increase in cosmic radiation does not fit any of the known extinction events that have happened in Earth's history. This does not mean nothing at all will happen to life during this time it only means the dangers are low.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to follow how the cosmic radiation changes you can do this on the last part of this page &lt;a href=&quot;http://spaceweather.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://spaceweather.com/&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Link &lt;a href=&quot;https://en.wikipedia.org/wiki/Cosmic_ray&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Cosmic_ray&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I mentioned in my comment Earth's magnetic north pole is really in the south. To understand how this can be true in a magnetic compass the magnetic north pole is repelled by Earth's north pole so it does point in the opposite direction (a bad explanation but it is how it works).&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="2470" LastEditDate="2019-06-01T13:28:24.717" LastActivityDate="2019-06-01T13:28:24.717" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17117" PostTypeId="1" AcceptedAnswerId="17123" CreationDate="2019-06-02T16:25:08.817" Score="3" ViewCount="135" Body="&lt;p&gt;Experts say up to 40 % of India might witness drought this year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there scientific evidence that this is due to the global warming and climate changes?&lt;/p&gt;&#xA;" OwnerUserId="17031" LastEditorUserId="2470" LastEditDate="2019-06-02T18:55:03.170" LastActivityDate="2019-06-03T06:29:51.167" Title="Is there scientific evidence connecting the current climate in India with global warming?" Tags="|climate-change|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17118" PostTypeId="1" AcceptedAnswerId="17135" CreationDate="2019-06-02T17:47:21.103" Score="1" ViewCount="165" Body="&lt;p&gt;I found &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Africa_(satellite_image).jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; one of Africa:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/t4XIS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/t4XIS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That one is nice because it's &gt; 3000x3000px which is large enough. I have looked around a bit for ones of these countries but haven't found anything that is large/high quality, free/public domain, and free of clouds/weather like the Africa image:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;United States&lt;/li&gt;&#xA;&lt;li&gt;Russia&lt;/li&gt;&#xA;&lt;li&gt;China&lt;/li&gt;&#xA;&lt;li&gt;India&lt;/li&gt;&#xA;&lt;li&gt;Mexico/Central America&lt;/li&gt;&#xA;&lt;li&gt;South America&lt;/li&gt;&#xA;&lt;li&gt;Canada&lt;/li&gt;&#xA;&lt;li&gt;Greenland/Iceland/Arctic&lt;/li&gt;&#xA;&lt;li&gt;Europe&lt;/li&gt;&#xA;&lt;li&gt;Australia&lt;/li&gt;&#xA;&lt;li&gt;Southeast Asia&lt;/li&gt;&#xA;&lt;li&gt;Japan&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I would like to find these broad areas as images on a high quality satellite image similar to this Africa one.&lt;/p&gt;&#xA;" OwnerUserId="784" LastActivityDate="2019-06-04T17:22:18.507" Title="Where I can find high-res public domain images of Countries or Continents on the web" Tags="|open-data|satellites|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17122" PostTypeId="1" CreationDate="2019-06-03T00:33:27.483" Score="4" ViewCount="961" Body="&lt;p&gt;The effective temperature of the Earth is roughly 12 °F (- 11 °C), which means that in thermal equilibrium when it is emitting as much radiation as it is absorbing, the distribution of wavelengths and intensities of electromagnetic radiation an observer in outer space would measure would correspond to the temperature of a blackbody object at 12 °F (- 11 °C)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, the surface of the Earth is actually much warmer than 12 °F (- 11 °C) due to the greenhouse effect. If there are greenhouse gases in an atmosphere then some fraction of infrared radiation from the terrestrial surface is absorbed by the atmosphere and re-emitted toward the ground. This re-emission of infrared radiation to the ground is like a trap for energy and over time it will cause the surface temperature of the planet to rise. This is right about where I have actual questions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the terrestrial surface is warming it will have to emit even more infrared radiation back to space. Is the atmosphere (and greenhouse gases) now absorbing the same fraction of a now larger amount of infrared radiation? in order to eventually rebalance incoming and outgoing radiation? I was thinking that the surface will grow warmer and emit more radiation until the amount exiting equals the amount incoming, establishing the new thermal equilibrium. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I often get confused because most diagrams for the Earth energy budget and net radiation balance show more infrared leaving the surface than is ever supplied by solar radiation at the top of the atmosphere in the first place. Is this because they count percentages or units of radiation twice? because some is re-emitted back?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have included a photo showing how the electromagnetic wave types are partitioned in the radiation balance. It is from NASA's CERES page. As you can see, more infrared is leaving Earth than enters as solar radiation and yet this is still a picture of equilibrium where the net radiation is zero. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9XFdH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9XFdH.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14316" LastEditorUserId="321" LastEditDate="2020-02-20T09:19:41.567" LastActivityDate="2020-02-20T09:19:41.567" Title="Effective Temperature of a Planet and Surface Temperature due to Greenhouse Effect" Tags="|atmospheric-radiation|solar-terrestrial-physics|greenhouse-gases|insolation|radiation-balance|" AnswerCount="2" CommentCount="5" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17123" PostTypeId="2" ParentId="17117" CreationDate="2019-06-03T04:46:20.497" Score="4" Body="&lt;p&gt;If you look at this link - &lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_of_India&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate Of India&lt;/a&gt; there are four seasons affecting different regions of India &lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Pre monsoon showers 2) Indian Summer Monsoon 3) Post monsoonal rain. 4) Winter rain&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each of them have their own patterns and dynamics. From the perspective of the second and biggest impact on the country i.e. Indian Summer Monsoon it would be hard to find a single year where rainfall distribution has been completely well distributed i.e. all regions of the country had experienced surplus rainfall. But this unequal distribution would be made up in subsequent years mitigating drought. Or so it was thought. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the monsoon to bring bountiful rainfall oceans must remain cool(relative to landmass) and land must warm during the crucial months of April and May. But this recent study published in Nature shows that there has been a  &lt;a href=&quot;https://www.nature.com/articles/ncomms8423?origin=ppub&quot; rel=&quot;nofollow noreferrer&quot;&gt;weakening of the land sea thermal gradient and drying up of Indian subcontinent&lt;/a&gt;/&lt;a href=&quot;http://www.indiaenvironmentportal.org.in/files/file/Drying%20of%20Indian%20subcontinent.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Drying up of Indian subcontinent due to weakening land sea thermal gradient&lt;/a&gt;. So according to that paper human influenced climate change causes the Indian  landmass to cool because increasing concentration of  aerosols suppress the surface warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly there is an asymmetry in the El Nino forcing.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Meanwhile, a recent study demonstrates that apart from the warming due to greenhouse gas forcing, the long-term warming trend in the western Indian Ocean is significantly associated with the asymmetry in the ENSO forcing. That is, while the quasi-periodic El Niño events induce a warming over the Indian Ocean via the Walker circulation, the La Niña events fail to do the inverse. Along with this, an increase in the magnitude and frequency of El Niños in the recent decades has accelerated this warming. The heat pile-up due to this ENSO forcing persists in the land-locked Indian Ocean that has a restricted thermohaline circulation, sustained by a feedback from the local air-sea interaction and ocean dynamics.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What this means is that the traditional monsoon dynamics i.e. cool Indian ocean and warm continental land mass has been disturbed by human influenced climate change as well as the natural geography of the land and ocean mass. One significant ISM phenomenon the tropical easterly jet stream &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/JCLI-D-13-00440.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;has shown a  weakening trend over the last few decades&lt;/a&gt;. A significant fall out of this could be mid latitude atmospheric dynamics could come into play during the ISM(one can think of this as the weather during a &lt;a href=&quot;http://moeseprints.incois.gov.in/3119/1/Break-Monsoon%20Over%20India.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;break in monsoons where upper level subtropical westerlies come into play&lt;/a&gt;) and a disturbing trend has been noted in recent times with increasing frequency of hail storms. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-06-03T06:29:51.167" LastActivityDate="2019-06-03T06:29:51.167" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17125" PostTypeId="2" ParentId="17099" CreationDate="2019-06-03T13:01:57.387" Score="3" Body="&lt;p&gt;Take a look at the &lt;a href=&quot;https://rdrr.io/cran/RSAGA/man/RSAGA-package.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;RSAGA&lt;/a&gt; package on CRAN, or the &lt;a href=&quot;https://www.rdocumentation.org/packages/rgdal/versions/1.4-3&quot; rel=&quot;nofollow noreferrer&quot;&gt;rgdal&lt;/a&gt; package. Many of the GIS methods can be done in R but basically act as a wrapper for saga or gdal. RSAGA is likely your best bet for processing terrains for flow analysis. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also know of &lt;a href=&quot;http://ibis.geog.ubc.ca/~rdmoore/Rcode.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dan Moore from UBC&lt;/a&gt; who does a lot of work with R and GIS applications, worth taking a look there and certainly those algorithms can be done in R directly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is also another post in the GIS forum on using TauDEM in R, worth taking a look as well. &lt;a href=&quot;https://gis.stackexchange.com/questions/84694/flow-accumulation-in-r&quot;&gt;TauDEM in R - additional SO post&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, &lt;a href=&quot;https://rseek.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;rseek&lt;/a&gt; is an excellent search engine for exactly this type of problem in case you don't find what you are looking for in those links above. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For actual flood routing, you may be interested in the Height Above Nearest Drainage Model (HAND), which uses the same type of D8 flow accumulation algorithm to build a rapid method for floodplain mapping. Good &lt;a href=&quot;https://ideas.repec.org/a/spr/nathaz/v93y2018i2d10.1007_s11069-018-3331-y.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt; on that some other 1D methods.&lt;/p&gt;&#xA;" OwnerUserId="8440" LastEditorUserId="8440" LastEditDate="2019-06-03T17:53:46.020" LastActivityDate="2019-06-03T17:53:46.020" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17126" PostTypeId="1" CreationDate="2019-06-03T15:48:08.000" Score="3" ViewCount="52" Body="&lt;p&gt;I was told by a sedimentologist there is no evidence of more climatic catastrophic events at the geological register previous to Pleistocene, when climate was warmer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is if meteorologists are showing an increase of this events due to climate change.&#xA;Are there more hurricans, big storms, suden inundations etc than before our emission of green-house gasses, or conversely the frequence of those events has stayed constant the last centuries? &lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-06-03T16:32:49.027" LastActivityDate="2019-06-03T16:32:49.027" Title="Are there more meteorological catastrophic events due to climate change?" Tags="|meteorology|climate-change|climate|storms|mesoscale-meteorology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17130" PostTypeId="1" CreationDate="2019-06-03T23:33:56.407" Score="3" ViewCount="332" Body="&lt;p&gt;My question in this post's title is predicated on &lt;a href=&quot;https://old.reddit.com/r/AskHistorians/comments/1fz39u/why_did_the_british_only_take_hong_kong_after_the/cafaj7u/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reddit&lt;/a&gt; -&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Hong Kong was perfect for the British as a staging point from which to trade with China. &lt;strong&gt;This was because Hong Kong has one of the best natural harbours in the world which was capable of protecting ships from the typhoon winds.&lt;/strong&gt; Also due to the British superiority in naval warfare Hong Kong could be easily defended from attacks. The taking of Hong Kong was primarily to establish a base from which Western (not just British) traders were able to sell opium to the Chinese without the Chinese being in a position to stop them. As far as I am aware there was never a desire to invade China, just trade for its silk, teas and manufactured goods.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I've riffled through some &lt;a href=&quot;https://www.google.com/search?client=firefox-b-d&amp;amp;biw=1344&amp;amp;bih=613&amp;amp;tbm=isch&amp;amp;sa=1&amp;amp;ei=uKz1XLPpCtKAtgWamI5Q&amp;amp;q=hong+kong+satellite+view&amp;amp;oq=hong+kong+satellite+view&amp;amp;gs_l=img.3..0.19010.19010..19596...0.0..0.126.126.0j1......0....1..gws-wiz-img.n0iL-t6yC5U#imgrc=_&quot; rel=&quot;nofollow noreferrer&quot;&gt;satellite views&lt;/a&gt; of HK, but I can't espy&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;which harbour is the one? &lt;a href=&quot;https://en.wikipedia.org/wiki/Victoria_Harbour&quot; rel=&quot;nofollow noreferrer&quot;&gt;Victoria Harbour&lt;/a&gt;?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;what makes HK so &quot;capable of protecting ships from the typhoon winds&quot;? &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.alamy.com/stock-photo-satellite-view-of-hong-kong-this-image-was-compiled-from-data-acquired-112373063.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;picture beneath&lt;/a&gt; &quot;was compiled from data acquired by Landsat 8 satellite in 2015.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7klgm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7klgm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user17042" LastActivityDate="2019-06-03T23:33:56.407" Title="Why does Hong Kong have one of the best natural harbours in the world that can protect ships from the typhoon winds?" Tags="|tropical-cyclone|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17131" PostTypeId="1" CreationDate="2019-06-04T03:35:44.443" Score="4" ViewCount="445" Body="&lt;p&gt;This question is based on the following graph from a &lt;a href=&quot;https://curryja.files.wordpress.com/2018/11/special-report-sea-level-rise3.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;2018 report by J. Curry&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(I haven't found any peer-review of the report itself so I can't vouch for the validity of its claims, but that's not the heart of the question)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bxRox.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bxRox.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I understand correctly, an idea developed by the report is that the observed rate of sea level rise during the 1850-1950 period can hardly be explained due to CO2 emissions, as those are barely significant prior to 1950.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter13_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;AR5 IPCC report on sea level change&lt;/a&gt; doesn't address this directly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What is the current consensus (if any) on the causes of the observed rate of sea level rise between 1850 and 1950 ?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(To be clear, I don't intend to question the &lt;em&gt;predicted&lt;/em&gt; sea level rise at all. This question is unrelated to the IPCC projections.)&lt;/p&gt;&#xA;" OwnerUserId="17044" LastEditorUserId="17044" LastEditDate="2019-06-05T05:05:33.117" LastActivityDate="2019-06-30T03:46:44.177" Title="Understood cause of sea level rise between 1850 and 1950" Tags="|climate-change|oceanography|sea-level|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17132" PostTypeId="2" ParentId="12013" CreationDate="2019-06-04T06:37:41.320" Score="0" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Residual soils or saprolite are soils that are derived in place from&#xA;  the weathering of the underlying bedrock.&gt; &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://docsbay.net/characterization-of-piedmont-residual-soil-and-saprolite-in-maryland&quot; rel=&quot;nofollow noreferrer&quot;&gt;Characterization of Piedmont Residual Soil and Saprolite in Maryland&lt;/a&gt; by &lt;em&gt;Missouri University of Science and Technology&lt;/em&gt; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The loose, fragmental material on the Moon’s surface is called&#xA;  regolith.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="17045" LastActivityDate="2019-06-04T06:37:41.320" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17133" PostTypeId="1" CreationDate="2019-06-04T08:21:24.107" Score="1" ViewCount="55" Body="&lt;p&gt;Background: I use the X-Plane flightsimulator for flying and gliding. In the program we have real weather (clouds, winds, etc...) but thermals are not well implemented, they don't have any connection with clouds or weather, they are just blue thermals. We can control its altitude, climb rate and coverage (percentage). I am thinking about writing a small plugin to control these preferences based on the real weather.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can you give a simple formula to roughly calculate thermal parameters based on data in METARs (temperature, drew point, cloud coverage/type, wind). Thanks!&lt;/p&gt;&#xA;" OwnerUserId="17046" LastEditorUserId="17046" LastEditDate="2019-06-04T08:36:09.293" LastActivityDate="2019-06-04T08:36:09.293" Title="Thermal likelihood formula" Tags="|meteorology|" AnswerCount="0" CommentCount="13" ContentLicense="CC BY-SA 4.0" />
  <row Id="17134" PostTypeId="1" CreationDate="2019-06-04T13:23:53.140" Score="1" ViewCount="53" Body="&lt;p&gt;I am finding angle between ship's heading and component in wave (wave's angle of attack), not sure if ES is a right place to ask this type of question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Should it be the difference between mean wave direction and vessel's azimuth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you for your time and concern reading my question,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sincerely,&lt;/p&gt;&#xA;" OwnerUserId="17038" LastEditorUserId="17038" LastEditDate="2019-06-05T13:31:19.950" LastActivityDate="2019-06-05T13:31:19.950" Title="Finding vessel and wave's angle of attack" Tags="|oceanography|ocean-currents|ocean-models|" AnswerCount="0" CommentCount="4" ClosedDate="2019-06-05T11:24:49.043" ContentLicense="CC BY-SA 4.0" />
  <row Id="17135" PostTypeId="2" ParentId="17118" CreationDate="2019-06-04T17:00:04.243" Score="1" Body="&lt;p&gt;You can find satellite images free of clouds at &lt;a href=&quot;https://zhfw.tianditu.gov.cn/&quot; rel=&quot;nofollow noreferrer&quot;&gt;chinesse version of google maps&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Under the rigth toolbar, top icon, you need to uncheck the first layer with the geographical names and click on the satellite image button, and you can place the view to see maps as this one of Southamerica. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8q0qo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8q0qo.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-06-04T17:22:18.507" LastActivityDate="2019-06-04T17:22:18.507" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17137" PostTypeId="2" ParentId="17122" CreationDate="2019-06-04T22:09:11.717" Score="5" Body="&lt;p&gt;I think you’re not far off with your understanding, but maybe I can put in a few comments to make things clearer.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I often get confused because most diagrams for the Earth energy budget and net radiation balance show more infrared leaving the surface than is ever supplied by solar radiation at the top of the atmosphere in the first place… As you can see, more infrared is leaving Earth than enters as solar radiation and yet this is still a picture of equilibrium where the net radiation is zero.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;These types of diagrams only show the fluxes, but you have to remember that the surface (mainly the ocean) and the atmosphere are reservoirs of energy that have built up over time.  In that diagram the top-of-atmosphere net radiation balance for the Earth system is,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;67 (absorbed by atmosphere) + 168 (absorbed by surface) = 235 (outgoing longwave radiation)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and all the other much larger components are just different pathways for energy transfer between those two internal reservoirs.  The sun only has to top-up the amount of energy that the reservoirs are leaking to space (235 W/m2) to maintain the equilibrium.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This re-emission of infrared radiation to the ground is like a trap for energy and over time it will cause the surface temperature of the planet to rise… If the terrestrial surface is warming it will have to emit even more infrared radiation back to space... I was thinking that the surface will grow warmer and emit more radiation until the amount exiting equals the amount incoming, establishing the new thermal equilibrium.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Broadly yes, but remember that the diagram you posted describes a long-term steady state (“thermal equilibrium”), so all that “warming” has already occurred and is built into those numbers.  It may just be your phrasing, but note that surface doesn’t emit the bulk of its thermal radiation directly back to space.  In your diagram this is the 40 W/m2 “atmospheric window”, which is much smaller than the 350 W/m2 of surface emission that’s absorbed by the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It might be better to think of the atmosphere less as trapping energy at the surface and more as slowing the net transfer of energy from the surface through the atmosphere to space.  Atmospheric science text books often include a cartoon to demonstrate how energy is absorbed and re-emitted as it passes through the atmosphere:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kFPas.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kFPas.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here each arrow is 1 arbitrary unit of energy.  Things to note are that (1) each layer emits as much as it receives, (2) there's a lot more than 1 unit of flux within the atmosphere, (3) there's a steady 1 unit of net flux through the atmosphere and (4) this equilibrium is maintained by 1 unit in and 1 unit out at the top of atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2019-06-04T22:09:11.717" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17141" PostTypeId="2" ParentId="17122" CreationDate="2019-06-05T22:45:02.560" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;diagrams for the Earth energy budget and net radiation balance show more infrared leaving the surface than is ever supplied by solar radiation at the top of the atmosphere in the first place. Is this because they count percentages or units of radiation twice? because some is re-emitted back?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Consider the simpler case of a blackbody. The incoming radiation is mostly in the visible spectrum. This warms the body, which radiates mostly in the infrared. At equilibrium, the power leaving is the same as the power supplied, although at different wavelengths.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-06-05T22:45:02.560" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17142" PostTypeId="1" AcceptedAnswerId="17146" CreationDate="2019-06-06T01:51:08.413" Score="7" ViewCount="1132" Body="&lt;p&gt;The Colorado River has been carving the Grand Canyon for a few million years now, such that the canyon floor is around 6000 feet lower in elevation than the surrounding area, at about 2400 feet above sea level. If things continue as they have, the Colorado River will continue to make the canyon deeper. If the river eroded away enough rock so that the river's bottom got to sea level, and this process continued to go upstream the river from where it empties into the Pacific Ocean so that the floor of the canyon eventually eroded below sea level, would the canyon gradually be filled in by the ocean? Would this even be possible? If not, why don't we see the mouth of the Colorado (or any river for that matter) gradually  move upstream, with ocean filling in where the river once was? &lt;/p&gt;&#xA;" OwnerUserId="17057" LastActivityDate="2019-06-06T18:00:43.067" Title="Could the Grand Canyon be flooded by the ocean if it got deep enough?" Tags="|geology|oceanography|rivers|erosion|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17143" PostTypeId="2" ParentId="9642" CreationDate="2019-06-06T02:58:29.310" Score="2" Body="&lt;p&gt;Easiest method I use is &lt;strong&gt;&quot;Lat(itude) = Fat(itude)&quot;&lt;/strong&gt;, imagining left-to-right lines of latitude looking like a fat belly (or belt) protruding over a tight belt. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That does the trick, but as a secondary mnemonic, I then imagine &quot;Long&quot; as a measure of tall/lankiness, as I'd never describe fatness/width as &quot;long&quot;.&lt;/p&gt;&#xA;" OwnerUserId="17058" LastActivityDate="2019-06-06T02:58:29.310" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17144" PostTypeId="2" ParentId="17131" CreationDate="2019-06-06T05:14:24.423" Score="2" Body="&lt;p&gt;SLR is thought to be caused by temperature rise, which is caused by CO2 rise and other factors. Temperature has been rising since before 1850. It could be another Question: &quot;Why temperature does not correspond with CO2 levels since 1850&quot;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/evpJD.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/evpJD.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;  The reconstructions used, in order from oldest to most recent publication are:&lt;br&gt;&#xA;  (dark blue 1000-1991): The Holocene.&lt;br&gt;&#xA;  (blue 1000-1980): Geophysical Research Letters.&lt;br&gt;&#xA;  (light blue 1000-1965): Ambio. Modified as published in Science.&lt;br&gt;&#xA;  (lightest blue 1402-1960): J. Geophys. Res..&lt;br&gt;&#xA;  (light green 831-1992): Science.&lt;br&gt;&#xA;  (yellow 200-1980): Geophysical Research Letters. doi:10.1029/2003GL017814.&lt;br&gt;&#xA;  (orange 200-1995): Reviews of Geophysics. doi:10.1029/2003RG000143&lt;br&gt;&#xA;  (red-orange 1500-1980): Geophys. Res Lett.. doi:10.1029/2004GL019781&lt;br&gt;&#xA;  (red 1-1979): Nature. doi:10.1038/nature03265&lt;br&gt;&#xA;  (dark red 1600-1990): Science. doi:10.1126/science.1107046&lt;br&gt;&#xA;  (black 1856-2004): Instrumental data was jointly compiled by the Climatic Research Unit and the UK Meteorological Office Hadley Centre.&lt;br&gt;&#xA;  &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:1000_Year_Temperature_Comparison.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Robert A. Rohde,  Creative Commons Attribution-Share Alike 3.0 Unported&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2019-06-30T03:46:44.177" LastActivityDate="2019-06-30T03:46:44.177" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17145" PostTypeId="2" ParentId="9642" CreationDate="2019-06-06T13:16:04.943" Score="7" Body="&lt;p&gt;Considering it's now my profession as a geomatics technician, I don't really need a mnemonic technique to remember which is which, but when I first had to remember the orientation of &lt;strong&gt;latitude&lt;/strong&gt; and &lt;strong&gt;longitude&lt;/strong&gt;, I simply did this:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Consider the equator as the horizon and switch two letters in &lt;strong&gt;latitude&lt;/strong&gt; so it becomes &lt;strong&gt;altitude&lt;/strong&gt;. There you go, latitude is the (angular) &lt;em&gt;height&lt;/em&gt; above the equator.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="17063" LastActivityDate="2019-06-06T13:16:04.943" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17146" PostTypeId="2" ParentId="17142" CreationDate="2019-06-06T14:26:37.557" Score="6" Body="&lt;p&gt;It is unlikely just from erosion. There are a couple reasons for this but because of the time scale over which this process would occur, other phenomenons might change the geologic picture completely.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason the canyon formed in the first place is because of tectonics that uplifted the rocks. From &lt;a href=&quot;https://www.nps.gov/grca/learn/nature/grca-geology.htm&quot; rel=&quot;noreferrer&quot;&gt;this page&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Uplift of the Colorado Plateau was a key step in the eventual formation of Grand Canyon. The action of plate tectonics lifted the rocks high and flat, creating a plateau through which the Colorado River could cut down.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Erosion is much quicker when the slope is steeper so the carving of the canyon slows down as the river flow gets gentler. So the deeper the canyon carves, the more potential force it loses. From the same source as the earlier quote, a stratigraphic profile:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GOEIu.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GOEIu.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another reason erosion has slowed down significantly is that the type of rock the water has to carve through is much different the deeper it gets. The river has now reached metamorphised layers that are much harder than the limestones and sandstones from the upper layers. The Vishnu Group is practically bedrock. &lt;a href=&quot;http://www.watersheds.org/earth/field.htm&quot; rel=&quot;noreferrer&quot;&gt;This page&lt;/a&gt; has a nice explanation:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The steeper the slope, the faster the runoff flow and the more force it will have to move material. The less vegetative (plant) cover and leaf material on the ground, the more open the soil will be to the flowing runoff water. Four things cause slope erosion: the amount and rate of rainfall, the steepness or gradient of the slope, the amount and nature of plant cover, and the type of soil and bedrock underneath.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Regarding this question:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;why don't we see the mouth of the Colorado (or any river for that matter) gradually move upstream, with ocean filling in where the river once was?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Erosion takes material away but this material has to go somewhere. Sediments are carried downstream and deposited at the mouth of those rivers, becoming what we call river deltas. The deltas usually advance &lt;strong&gt;into&lt;/strong&gt; the sea as the mass of sediments is incredibly huge. Take a look at this picture:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nbktZ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nbktZ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the eastern end of Lake Mead where the Colorado river would flow when the reservoir level was higher. The entire flat brownish area is deposited silt from around 50 years of flow. I rafted through that now exposed silt and the walls on either side of the new channel were over 30 feet high. The same thing occurs in the oceans, but over much longer timescales.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, to summarize:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;There is much less water flowing through now than in the past. If Colorado winters become too mild and dry, then the river's power will be even further diminished.&lt;/li&gt;&#xA;&lt;li&gt;The slope gradient of the river can only get gentler, so erosion will slow down.&lt;/li&gt;&#xA;&lt;li&gt;The river has reached much harder rock that resists erosion much better.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="17063" LastEditorUserId="17063" LastEditDate="2019-06-06T14:46:24.277" LastActivityDate="2019-06-06T14:46:24.277" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17147" PostTypeId="2" ParentId="17142" CreationDate="2019-06-06T18:00:43.067" Score="2" Body="&lt;p&gt;It would be unlikely for the Grand Canyon/Colorado, simply because the mouth of the river is too far from the ocean, and the outlet is in the relatively shallow end of the Sea of Cortez: &lt;a href=&quot;https://en.wikipedia.org/wiki/Gulf_of_California&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Gulf_of_California&lt;/a&gt;  That means that sediments will be deposited to form a delta &lt;a href=&quot;https://en.wikipedia.org/wiki/Colorado_River_Delta&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Colorado_River_Delta&lt;/a&gt; and as the upper reaches of the river erode towards sea level, the water will flow slower, eroding less.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, there are a couple of cases where something similar can happen.  The first is where the eroding force is not a river, but a glacier.  The weight of the ice means it extends well below sea level, eroding the rock.  The classic example of this, of course, are the Norwegian fiords.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A second case is where the sea floor drops fairly quickly to the depths.  Then the sediments will flow in turbidity currents, eroding an undersea canyon.  Examples are the Monterey Canyon &lt;a href=&quot;https://en.wikipedia.org/wiki/Monterey_Canyon&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Monterey_Canyon&lt;/a&gt; and the Hudson Canyon: &lt;a href=&quot;https://en.wikipedia.org/wiki/Hudson_Canyon&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Hudson_Canyon&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course this is all complicated by changes in sea level over geologic time scales.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2019-06-06T18:00:43.067" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17149" PostTypeId="2" ParentId="14212" CreationDate="2019-06-06T19:55:31.247" Score="4" Body="&lt;p&gt;Other answers have suggested some ways of classifying things into seas or lakes, which are good guides, but inevitably there are exceptions to all of them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ultimately, the difference is not an oceanographic or hydrological one, but a semantic and cultural one. The names bodies of water have are historical, so what they are called is down to what somebody saw fit to call them in the past - not any modern taxonomy.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-06-06T19:55:31.247" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17153" PostTypeId="2" ParentId="9089" CreationDate="2019-06-07T13:03:45.993" Score="1" Body="&lt;p&gt;The idea that decomposers that consume the wood's carbon just die and release it is foolish. These decomposers are at the base of a complex food web that moves that carbon through a huge network. I haven't seen a study to quantify the amount of carbon released to the atmosphere, but it is an important question. I have seen many studies trying to get at the question of how much carbon is incorporated into the soil, but each situation is so different that it is hard to get a clear answer.&lt;/p&gt;&#xA;" OwnerUserId="17071" LastEditorUserId="2470" LastEditDate="2019-06-07T13:17:58.833" LastActivityDate="2019-06-07T13:17:58.833" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17154" PostTypeId="2" ParentId="4466" CreationDate="2019-06-07T16:10:50.963" Score="2" Body="&lt;p&gt;If you look at early prehistoric Australia.  Australia was connected to what is&#xA;Indoneasia (Papua) and Papua New Guinea.  There is a land bridge which the ocean&#xA;rose over and it still exists today which is called the Torres Strait land bridge.  The waters are a maximum of 60 feet in depth.  It is not out of the question that GAB was filled up by a PNG aquifer or underground river and became salty from the Australian crust.  In the Gulf of Carpentaria there is a shallow lake submerged and what is the Fly river in PNG used to flow south into this shallow lake which is part of the Gulf of Carpentaria sea bed. There is proof already that some water was shared or transferred in the prehistoric past from PNG to Australia when both shared the same land mass called Sahul.&lt;/p&gt;&#xA;" OwnerUserId="17072" LastActivityDate="2019-06-07T16:10:50.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17156" PostTypeId="1" CreationDate="2019-06-08T18:03:19.210" Score="1" ViewCount="82" Body="&lt;p&gt;Where can I find a model of Earth's past climates and future projections from combined possibilities like magnetic pole movement and other forms of global warming as a map? Without a reference it has been said that enough heat could trigger a mini ice age.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At what temperature change would people have to migrate towards or away from the equator?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/17110/what-happens-when-the-north-and-south-poles-flip&quot;&gt;What happens when the North and South poles flip?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2019-06-08T18:31:08.540" LastActivityDate="2019-06-08T18:31:08.540" Title="Can we predict the rising temperature of Earth?" Tags="|climate-change|sun|human-influence|geomagnetism|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17161" PostTypeId="1" CreationDate="2019-06-09T21:40:07.633" Score="5" ViewCount="170" Body="&lt;p&gt;Why is such an emphasis placed on sea level rise?? As this can be devastating in itself, it can be looked at as a great economic opportunity to put people to work preparing our coastal areas for the inevitable, but slowly progressing future situation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Isn't the disruption of ocean currents (as portrayed in &quot;Day After Tomorrow&quot; or in Peter Ward's Medea hypothesis (hydrogen sulfide poisoning)) even more serious?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are also major consequences such as fresh water shortage, ocean acidification, decrease in biodiversity, etc. etc. Some of the worst consequences may be ones we haven't even thought of yet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I feel that we are oversimplifying the message to the public by focusing on sea level rise. Am I wrong??&lt;/p&gt;&#xA;" OwnerUserId="4600" LastActivityDate="2019-06-11T01:18:37.337" Title="The seriousness of global warming/ climate change?" Tags="|climate-change|" AnswerCount="2" CommentCount="1" ClosedDate="2019-06-11T10:04:20.660" ContentLicense="CC BY-SA 4.0" />
  <row Id="17162" PostTypeId="2" ParentId="17161" CreationDate="2019-06-10T03:57:44.227" Score="5" Body="&lt;p&gt;Try asking Pacific Islanders that question.  Most Pacific islands are only a few meters above sea. Some have already had their fresh water sources, destroyed by rising sea levels. Most of these people are in danger of losing the land beneath their feet &amp;amp; becoming environmental refugees.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then there is Bangladesh, a low lying country, without any hard rock, where gravel is made by baking clay. It already is losing significant parts of the country to coastal erosion, some of which was farmland.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you're not concerned about Pacific islanders or Bangladeshis, then how about Europeans? Significant portions of the Netherlands are already &lt;strong&gt;below&lt;/strong&gt; sea level, sustained by a system of dykes and sea walls. Some of theses are in danger of being overwhelmed by rising oceans and the land being lost.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you're not concerned about Europeans, then how about Americans? Will Americans want to pay for system of sea walls to protect New Orleans? It already has issues trying to build a wall along its border with Mexico, but that's another issue.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rising sea levels will inundate land with salty sea water and it cause the lose of softer coastal terrain to erosion, such as limestone cliff terrain in Britain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other thing that rarely gets mentioned is the affect that lost coastal habitats, such as mangroves, will have on non-human life. As if human life is the only form of life that matters on the planet and that nature is irrelevant. Humans need nature more than nature needs humans. Some of these habitats are critical to the some fish species and other life forms.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-06-10T03:57:44.227" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17165" PostTypeId="2" ParentId="4466" CreationDate="2019-06-10T20:47:11.930" Score="0" Body="&lt;p&gt;If you look at an average precipitation map of Australia for the last decade or&#xA; decades you will note that the CSIRO recharge areas are not in high&#xA;precipitation zones except for the tip of Cape York.  The Great Artesian Basin&#xA;is fossil water and the Australian government has taken measures to shut down&#xA;open bore holes which have flowed for many decades out of concern that the&#xA;GAB may run out of water since the recharge rates are negligible.&lt;/p&gt;&#xA;" OwnerUserId="17093" LastActivityDate="2019-06-10T20:47:11.930" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17166" PostTypeId="2" ParentId="17161" CreationDate="2019-06-11T01:18:37.337" Score="3" Body="&lt;p&gt;Sea level is a simple single number which stands in for a host of effects. Also much of the world's population lives on the coast (&lt;a href=&quot;https://doi.org/10.1177/0956247807076960&quot; rel=&quot;nofollow noreferrer&quot;&gt;10% population in 2% of land area&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other effects from sea level rise:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Increased risk of flooding during storm surge&lt;/li&gt;&#xA;&lt;li&gt;Salwater intrusion in bodies close to sea water, e.g. Amazon, everglades, coastal aquifers (&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S2352801X16300194&quot; rel=&quot;nofollow noreferrer&quot;&gt;Egypt&lt;/a&gt;, &lt;a href=&quot;https://escholarship.org/uc/item/38w0p9st&quot; rel=&quot;nofollow noreferrer&quot;&gt;California&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;Changing ocean currents from freshwater flux (partial cause of sea leve rise)&lt;/li&gt;&#xA;&lt;li&gt;Changing coastal processes (erosion, sand deposition)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Also when drawing the relationship between CO2 concentration and climate impact, we can point directly to the CO2 and global land ice volume (conversely sea level) relationship. This has been worked out in measurements from ice cores, marine cores, and sea level proxies (e.g. corals, paleo-shorelines).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You're right there are other issues but sea level is the most concrete, measurable, and globally impactful.&lt;/p&gt;&#xA;" OwnerUserId="17094" LastActivityDate="2019-06-11T01:18:37.337" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17169" PostTypeId="1" AcceptedAnswerId="17171" CreationDate="2019-06-11T17:35:27.360" Score="4" ViewCount="86" Body="&lt;p&gt;I downloaded a grib file of oceanography (Mean Wave Period) from ERA-Interim and the longitude values give the value at the points is 0,1, 2, 3....357, 358, 359&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I have geographical coordinates that fall between the range 359 to 360 degree longitude. How can I represent them? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you for your time and concern reading my question, &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sincerely, &lt;/p&gt;&#xA;" OwnerUserId="17038" LastActivityDate="2019-06-11T22:32:07.923" Title="What is the weather data covering the range of 359 to 360 degree" Tags="|oceanography|ocean-currents|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17171" PostTypeId="2" ParentId="17169" CreationDate="2019-06-11T22:24:15.833" Score="8" Body="&lt;p&gt;Remember that 360° == 0°. They're the same line of longitude. So the gap between 359° and 0° is no more than the gap between 1° and 2°, and should be handled the same way.&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2019-06-11T22:32:07.923" LastActivityDate="2019-06-11T22:32:07.923" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="17173" PostTypeId="1" CreationDate="2019-06-12T04:07:18.380" Score="3" ViewCount="110" Body="&lt;p&gt;How and when was the &lt;span class=&quot;math-container&quot;&gt;$\mathsf{CO_2}$&lt;/span&gt; removed in primordial Earth atmosphere? What is the main mechanism of this removal of &lt;span class=&quot;math-container&quot;&gt;$\mathsf{CO_2}$&lt;/span&gt;? Is it dissolving in water? Or rock weathering? Or was the bulk of &lt;span class=&quot;math-container&quot;&gt;$\mathsf{CO_2}$&lt;/span&gt; actually removed by early life?&lt;/p&gt;&#xA;" OwnerUserId="15432" LastActivityDate="2019-06-20T12:59:20.353" Title="How and when was the $\mathsf{CO_2}$ scrubbed when Earth was still primordial?" Tags="|atmosphere|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17177" PostTypeId="1" CreationDate="2019-06-12T11:08:48.040" Score="1" ViewCount="30" Body="&lt;p&gt;Could someone please explain what exactly is shown on the following image? I have a few questions such as:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/0lEqK.png&quot; alt=&quot;Image of a map&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How did the 'Banc à la Ligne' come about? (I know it has something to do with the fact that the beach drift is subject to south-west winds, and the orientation change of the coast)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why are the western sectors (Dune du Chatelet, Dune d'Aval) eroded in contrast to the more eastern locations (Dune d'Amont)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I read somewhere that the height of the dunes is increasing towards the east, what is the explanation for this?&lt;/p&gt;&#xA;" OwnerUserId="17105" LastEditorUserId="6550" LastEditDate="2019-06-23T18:41:34.780" LastActivityDate="2019-06-23T18:41:34.780" Title="A few questions about the morphology and sediment dynamics of Wissant Bay (France)" Tags="|geography|sedimentology|coastal|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17178" PostTypeId="1" CreationDate="2019-06-12T16:44:07.357" Score="4" ViewCount="52" Body="&lt;p&gt;I was searching for the climate of Saudi Arabia and I noticed that the city of Abha (altitude of 7000 feet) has a &quot;strange&quot; behavior in its dew point, as numbeo suggests: &lt;a href=&quot;https://www.numbeo.com/climate/in/Abha-Saudi-Arabia&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.numbeo.com/climate/in/Abha-Saudi-Arabia&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I mean is that the dewpoint oscillates throughout the year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone have any idea about why?&lt;/p&gt;&#xA;" OwnerUserId="17108" LastEditorUserId="6258" LastEditDate="2019-06-12T18:38:45.773" LastActivityDate="2019-06-12T18:38:45.773" Title="Oscillating dew point throughout the year?" Tags="|meteorology|atmosphere|climate|humidity|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17179" PostTypeId="1" CreationDate="2019-06-12T19:13:41.473" Score="2" ViewCount="1688" Body="&lt;p&gt;I'm currently working on some software for cloud masking, and thus far I have only been using satellite data as recent as spring (northern hemisphere). However, I'm wondering if cloud coverage or formations have a noticeable change across different seasons?&lt;/p&gt;&#xA;" OwnerUserId="17111" LastActivityDate="2024-01-24T14:32:44.383" Title="Do cloud formations change depending on the season?" Tags="|meteorology|climate|clouds|climatology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17181" PostTypeId="2" ParentId="10472" CreationDate="2019-06-12T23:07:07.790" Score="-1" Body="&lt;p&gt;&quot;Metamorphic rocks arise from the transformation of existing rock types&quot;&#xA;&quot;a natural substance, a solid aggregate of one or more minerals or mineraloids.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looks like Metamorphic wins. &lt;/p&gt;&#xA;" OwnerUserId="17114" LastActivityDate="2019-06-12T23:07:07.790" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17182" PostTypeId="1" CreationDate="2019-06-12T23:35:29.777" Score="6" ViewCount="504" Body="&lt;p&gt;&lt;a href=&quot;https://space.stackexchange.com/q/36702/11181&quot;&gt;Can artificial satellite positions affect tides?&lt;/a&gt; on Space Exploration.SE asks if artificial satellites can affect tides, because they are a lot closer than our natural satellite, even though they are much smaller in mass.  The &lt;a href=&quot;https://space.stackexchange.com/a/36703/11181&quot;&gt;top answer&lt;/a&gt; to that question is basically &quot;no.&quot; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A &lt;a href=&quot;https://space.stackexchange.com/questions/36702/can-artificial-satellite-positions-affect-tides#comment116761_36703&quot;&gt;commenter&lt;/a&gt; estimates that Pluto might have a larger effect, but Pluto is such a distant object I didn't think most people could easily relate to that, so I tried running the numbers with something people might be more familiar with, closer to our surface: airplanes.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Let's start by considering a big plane in relatively common use.  The Boeing 747 is well known as a popular aircraft type, and it &lt;a href=&quot;http://www.boeing.com/commercial/747&quot; rel=&quot;nofollow noreferrer&quot;&gt;seems&lt;/a&gt; that the version of it they're producing now is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Boeing_747-8&quot; rel=&quot;nofollow noreferrer&quot;&gt;Boeing 747-8&lt;/a&gt;.  &lt;a href=&quot;https://www.flugzeuginfo.net/acdata_php/acdata_boeing_7478_en.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;This page&lt;/a&gt; says it has a maximum takeoff weight of 4.48*10&lt;sup&gt;5&lt;/sup&gt; kg and a maximum landing weight of 3.12*10&lt;sup&gt;5&lt;/sup&gt; kg, with a service ceiling of 1.3*10&lt;sup&gt;4&lt;/sup&gt; m.  I'll round that to a weight of 3.5*10&lt;sup&gt;5&lt;/sup&gt; kg mass and 1*10&lt;sup&gt;4&lt;/sup&gt; m height above the surface of the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, the moon.  &lt;a href=&quot;https://en.wikipedia.org/wiki/Moon&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; says the moon has a mass of around 7*10&lt;sup&gt;22&lt;/sup&gt; kg and a distance from the center of the earth on the order of 4*10&lt;sup&gt;6&lt;/sup&gt; km, which is 4*10&lt;sup&gt;9&lt;/sup&gt; m.  Earth's radius, about 6.3*10&lt;sup&gt;3&lt;/sup&gt; km, is about a tenth of a percent of that distance and lost in the rounding/simplification of the Moon's orbit to be circular instead of its actual eccentricity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This means that the moon's mass is (7*10&lt;sup&gt;22&lt;/sup&gt; kg / 3.5*10&lt;sup&gt;5&lt;/sup&gt; kg =) 2*10&lt;sup&gt;17&lt;/sup&gt; times that of the 747.&#xA;The moon's distance from the surface of the ocean is (4*10&lt;sup&gt;9&lt;/sup&gt; m / 1*10&lt;sup&gt;4&lt;/sup&gt;m =) 4*10&lt;sup&gt;5&lt;/sup&gt; times that of the 747.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Comments on &lt;a href=&quot;https://space.stackexchange.com/a/36703/11181&quot;&gt;this answer&lt;/a&gt; note that &quot;the amplitude of tides is proportional not to the strength of the gravity force, which is proportional to r&lt;sup&gt;2&lt;/sup&gt;, but to its gradient, which is proportional to r&lt;sup&gt;3&lt;/sup&gt;...a factor of 10&lt;sup&gt;3&lt;/sup&gt; in distance means a factor of 10&lt;sup&gt;9&lt;/sup&gt; in tidal effect.&quot;  Therefore, the effect that the distance has on the amplitude would be ((4*10&lt;sup&gt;5&lt;/sup&gt;)&lt;sup&gt;3&lt;/sup&gt; =) 6.4*10&lt;sup&gt;16&lt;/sup&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus the overall effect of the 747 on tides should be (6.4*10&lt;sup&gt;16&lt;/sup&gt; / 2*10&lt;sup&gt;17&lt;/sup&gt; =) &lt;strong&gt;about a third of the effect of the moon&lt;/strong&gt;.  It's a back-of-the-envelope order-of-magnitude calculation, but a much larger result than I expected.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Did I mess up somewhere in the math or facts above?  (If not, I'm willing to cut &amp;amp; paste that content into an Answer, but for now it's just showing the work I've done in arriving at this question and attempting to solve it myself.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, there are &lt;strong&gt;many&lt;/strong&gt; flights in the sky at any given moment, all around the world, and to a certain extent any tidal effects of one flight would be cancelled out by the effects of one or more others.   However, the flight map is not completely balanced or evenly distributed north-south or east-west. &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Do flights affect tides?&lt;/p&gt;&#xA;" OwnerUserId="3244" LastEditorUserId="3244" LastEditDate="2019-06-17T15:50:14.487" LastActivityDate="2019-06-17T15:50:14.487" Title="Do flights affect tides?" Tags="|human-influence|tides|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17183" PostTypeId="1" CreationDate="2019-06-13T00:00:18.610" Score="1" ViewCount="141" Body="&lt;p&gt;In Cunningham's paper, &lt;a href=&quot;https://miningandblasting.files.wordpress.com/2009/09/the-kuz-ram-fragmentation-model-e28093-20-years-on.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;&quot;The Kuz-Ram fragmentation model - 20 years on&quot;&lt;/em&gt;&lt;/a&gt;, he makes mention of &lt;em&gt;compressional stress wave velocity&lt;/em&gt;, &lt;strong&gt;C&lt;sub&gt;p&lt;/sub&gt;&lt;/strong&gt;. He only comments that the &lt;strong&gt;C&lt;sub&gt;p&lt;/sub&gt;&lt;/strong&gt; of granite = 5.2 km/s. I using a relation that includes &lt;strong&gt;C&lt;sub&gt;p&lt;/sub&gt;&lt;/strong&gt; but the rock type is not granite. A search on Google for the exact mention of compressional stress wave velocity lists only 3 results all of which are either the same paper or refer to Cunningham's paper.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Is there a table where I can check the &lt;strong&gt;C&lt;sub&gt;p&lt;/sub&gt;&lt;/strong&gt; for the rock type? &lt;/li&gt;&#xA;&lt;li&gt;Is there a relation that I can use to derive the value of &lt;strong&gt;C&lt;sub&gt;p&lt;/sub&gt;&lt;/strong&gt; based on other known values of the rock&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Any of the above is acceptable. Thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="17115" LastActivityDate="2019-06-15T12:10:22.717" Title="How to calculate or find the compressional stress wave velocity, Cp for a rock" Tags="|rocks|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17184" PostTypeId="2" ParentId="17182" CreationDate="2019-06-13T02:33:11.930" Score="-1" Body="&lt;p&gt;I think you should calculate the distance between the plane and the oceanic floor (instead the surface), or at least some depth. Unlike plane, the moon has almost the same gravitational influence on the surface of the oceans as in the deepest ocean trenches.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plus, planes flies very fast and are very small objects. Oceans moves too slow, a wave can't follow each plane. No temporary effect is measurable because instantly dissipated by the waves (think about wind). The gravitational influence of the moon affects a vast part of the ocean, giving it time to react.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oil platforms have certainly more influences, they are just above the surface, heavier, can be far in the ocean and do not move!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Planes have surely more influence on weather (due to reactors / fuel) than waves.&lt;/p&gt;&#xA;" OwnerUserId="17117" LastActivityDate="2019-06-13T02:33:11.930" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="17185" PostTypeId="1" CreationDate="2019-06-13T04:05:37.923" Score="2" ViewCount="111" Body="&lt;p&gt;Volcanic eruptions, undersea earthquakes, fissures in the crust, meteoroid accumulation could all be seen as empirical evidence of expansion of the earth. Sink holes and other phenomena could be contrary evidence. Subduction of crustal layers and changes in the earth's rate of rotation could be cited as evidence one way or the other. But the net effect, if measurable at all, might well fall within the range of inaccuracy of the earth's volume estimate. &#xA;Moreover, nuclear fission produces elements of lesser density. Could this process not produce a reduction of density in the mantle, and hence provide a mechanism for expansion of the earth?&#xA;I realize that the effect of these factors, although large on a human scale, may well be tiny when compared to the total earth volume.&#xA;Nonetheless, whatever the measurement or estimate of these factors, how can their effect on the earth's volume, over eons, be considered insignificant, if the accuracy of the total volume of the earth is not known to a degree of certainty?&lt;/p&gt;&#xA;" OwnerUserId="17118" LastActivityDate="2019-06-13T16:00:52.683" Title="If the accuracy of measurement of the earth's volume is not known, how can scientists assert that the earth is not expanding?" Tags="|geophysics|measurements|geodesy|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17186" PostTypeId="2" ParentId="17182" CreationDate="2019-06-13T07:27:55.713" Score="4" Body="&lt;p&gt;A plane might be located 1.3*10&lt;sup&gt;3&lt;/sup&gt; meters away from the surface of the ocean right underneath it, but for most of the ocean, it's located much further away, and at a very different angle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While it may pull more than the moon on the water it flies over for the short time it flies over it, that doesn't make a &lt;em&gt;tide&lt;/em&gt; by any definition. At most a wave. But I think that effect is hardly significant as opposed to other effects creating waves. I'm not that knowledgeable on the maths, though.&lt;/p&gt;&#xA;" OwnerUserId="17120" LastActivityDate="2019-06-13T07:27:55.713" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17187" PostTypeId="2" ParentId="17179" CreationDate="2019-06-13T14:35:37.753" Score="5" Body="&lt;p&gt;Yes. The types of clouds formed are dependent on the profile of temperature and the profile of water vapor. During the summer, there is more radiative flux, which produces more buoyancy. Hence more buoyant clouds (cumulus-type) are formed in the summer than in the winter. Instinctively you may recognize that you get more thunderstorms during the summer than the winter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthsky.org/earth/kelvin-helmholzt-clouds&quot; rel=&quot;noreferrer&quot;&gt;Kelvin-Helmholtz wave clouds&lt;/a&gt; usually need different densities of air, typical of an inversion. This is more likely to happen during cooler seasons (Fall, Winter, and Spring).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, freezing fog is inherently more common in the winter than the summer. &lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2019-06-13T14:35:37.753" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17188" PostTypeId="2" ParentId="17185" CreationDate="2019-06-13T16:00:52.683" Score="7" Body="&lt;p&gt;In short, the current volume of the earth is known to great precision and modern measurements show no significant expansion at meaningful scales.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Facing 20th century evidence that points on the globe -- such as the edges of continents -- that are now distant from each other were once adjacent, some scientists argued that the only explanation was the ongoing expansion of the earth's surface. That argument collapsed by the 1960s, as overwhelming evidence accumulated for the theory of plate tectonics -- that is, roughly, there are relatively rigid continental plates that move across the surface of the earth, with the ocean floor between them created at the mid-ocean ridges and destroyed by subduction under the continental margins. Broad calculations showed that the volumes of the two processes were close enough to cancel each other out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the modern era dependent on the accuracy of satellite positions for GPS, sea-level rise measurement, and other detailed geodetic measurements, there was a need to resolve the question of whether the earth's volume was changing in a more conclusive and precise way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the studies that addresses that is the 2011 paper &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011GL047450&quot; rel=&quot;noreferrer&quot;&gt;Accuracy of the International Terrestrial Reference Frame origin and Earth expansion&lt;/a&gt;, published in &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/journal/19448007&quot; rel=&quot;noreferrer&quot;&gt;Geophysical Research Letters&lt;/a&gt;, a journal of the international &lt;a href=&quot;https://sites.agu.org/&quot; rel=&quot;noreferrer&quot;&gt;American Geophysical Union&lt;/a&gt;. Most of the paper discusses the technical processes and calculations, but it concludes:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A possible secular change in the mean radius of the solid Earth has&#xA;  long been suspected from various scientific disciplines. The problem&#xA;  was not settled due to lack of a proven theory and the inherent&#xA;  difficulty in actually determining such a change. By using the data&#xA;  combination and the simultaneous global inverse approach, the issue of&#xA;  aliasing from the geophysical processes due to network sparseness is&#xA;  largely overcome here. In fact, our uncertainty in the mean expansion&#xA;  rate determination is dominated by an ITRF [International Terrestrial Reference Frame ] scale drift uncertainty of&#xA;  0.16 mm yr−1 estimated from comparing VLBI [Very Long Baseline Interferometry] and SLR [satellite laser ranging]. &lt;strong&gt;In conclusion, no statistically significant present expansion rate is detected by our&#xA;  study within the current measurement uncertainty of 0.2 mm yr−1&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2019-06-13T16:00:52.683" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17190" PostTypeId="2" ParentId="17182" CreationDate="2019-06-13T18:51:54.660" Score="5" Body="&lt;p&gt;Both airborne planes and the Moon affect the tides, but the effect of airborne planes is so small as to be negligible. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;From your sources the mass of a Boeing 747 (&lt;span class=&quot;math-container&quot;&gt;$m_{747}$&lt;/span&gt;) is &lt;span class=&quot;math-container&quot;&gt;$447.696$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$(10)^3$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$kg$&lt;/span&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Likewise, from your sources, the mass of the Moon (&lt;span class=&quot;math-container&quot;&gt;$m_{Moon}$&lt;/span&gt; is&#xA;&lt;span class=&quot;math-container&quot;&gt;$7.347$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$(10)^{22}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$kg$&lt;/span&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Typically a 747 would fly at an altitude (&lt;span class=&quot;math-container&quot;&gt;$r_{747}$&lt;/span&gt;) of around &lt;span class=&quot;math-container&quot;&gt;$30$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$000$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$ft$&lt;/span&gt;. This is close to &lt;span class=&quot;math-container&quot;&gt;$10$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$000$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt; (&lt;span class=&quot;math-container&quot;&gt;$10^4$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt;).&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Lunar_distance_(astronomy)&quot; rel=&quot;noreferrer&quot;&gt;The distance the Moon&lt;/a&gt; is from the Earth (&lt;span class=&quot;math-container&quot;&gt;$r_{Moon}$&lt;/span&gt;) is &lt;span class=&quot;math-container&quot;&gt;$384$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$400$&lt;/span&gt;  &lt;span class=&quot;math-container&quot;&gt;$km$&lt;/span&gt;, which is &lt;span class=&quot;math-container&quot;&gt;$384.4$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$(10)^6$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Now, &lt;a href=&quot;https://en.wikipedia.org/wiki/Newton%27s_law_of_universal_gravitation&quot; rel=&quot;noreferrer&quot;&gt;Newton's Law of Universal Gravitation&lt;/a&gt; states, &lt;span class=&quot;math-container&quot;&gt;$F$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$=$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;${G.m_1.m_2}/{r^2}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where:&#xA;&lt;span class=&quot;math-container&quot;&gt;$G$&lt;/span&gt; is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Gravitational_constant&quot; rel=&quot;noreferrer&quot;&gt;gravitational constant&lt;/a&gt;, being &lt;span class=&quot;math-container&quot;&gt;$6.6743$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$10^{-11}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$m^3.kg^{-1}.s^{-2}$&lt;/span&gt;,&#xA;&lt;span class=&quot;math-container&quot;&gt;$m_1$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$m_2$&lt;/span&gt; are the masses of the two objects being considered &amp;amp; &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; is the distance between them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because tides are being considered only the mass of water is to be considered, not the mass of the Earth. To simplify things I am assuming the area of water affect by each is the same and hence the mass of water will be the same in each case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;For the Earth and Moon system, the force of gravity will be:&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$F_{E-M}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$=$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$6.6743(10)^{-11}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$.$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$7.347(10)^{22}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$.$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$m_{ocean}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$/$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$[{384.4(10)^6}]^2$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$=$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$3.3186(10)^{-5}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$.$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$m_{ocean}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;For the Earth Boeing 747 system, the force of gravity will be:&lt;/em&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$F_{E-747}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$=$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$6.6743(10)^{-11}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$.$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$447.696(10)^{3}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$.$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$m_{ocean}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$/$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$[{(10)^4}]^2$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$=$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$2.9881(10)^{-13}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$.$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$m_{ocean}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Dividing &lt;span class=&quot;math-container&quot;&gt;$F_{E-M}$&lt;/span&gt; by &lt;span class=&quot;math-container&quot;&gt;$F_{E-747}$&lt;/span&gt; the gravitational force of the Moon is &lt;span class=&quot;math-container&quot;&gt;$111$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$060$&lt;/span&gt; greater than that of the plane.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the tides produced by the Moon are up to &lt;span class=&quot;math-container&quot;&gt;$10$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt;, then the maximum height of a tide produced by a 747 would be around &lt;span class=&quot;math-container&quot;&gt;$0.099$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$mm$&lt;/span&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-06-13T18:51:54.660" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17194" PostTypeId="2" ParentId="17085" CreationDate="2019-06-14T13:11:07.903" Score="1" Body="&lt;p&gt;According to &lt;a href=&quot;https://www.cs.mcgill.ca/~rwest/wikispeedia/wpcd/wp/s/Seawater.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;this site&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Chloride comes from underwater fumaroles (such as black smokers), whose &lt;em&gt;smoke&lt;/em&gt; is the exhalation of the vapors that escape from the magma as it rises next to subsurface. There is very little Chloride in magma, less than 1% (of the gaseous content, which is a small fraction of the magma as well), but the massive volume of magma that is output makes up for it. Dissolved anions are also a possibility, albeit a less significant one. &lt;/p&gt;&#xA;" OwnerUserId="13211" LastActivityDate="2019-06-14T13:11:07.903" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17197" PostTypeId="2" ParentId="16852" CreationDate="2019-06-14T22:20:09.220" Score="1" Body="&lt;p&gt;You might be viewing the problem in wrong light. Given this graph we want to find the velocity V1 (a parameter that defines the shape of hyperbola). V1 has effect on shape of hyperbola as whole. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Instantaneous velocity does not make sense here. I would term it as &quot;apparent velocity&quot;, as you are using single point data rather than the whole hyperbola to judge velocity of the medium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hyperbolic equation is &lt;span class=&quot;math-container&quot;&gt;$t^2= (x/v1)^2 + (2h/v1)^2$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can use &lt;span class=&quot;math-container&quot;&gt;$X^2-T^2$&lt;/span&gt; plot and find the slope and therefore &lt;span class=&quot;math-container&quot;&gt;$v1$&lt;/span&gt; using linear regression. &lt;/p&gt;&#xA;" OwnerUserId="11861" LastActivityDate="2019-06-14T22:20:09.220" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17199" PostTypeId="1" AcceptedAnswerId="17210" CreationDate="2019-06-15T00:07:42.167" Score="2" ViewCount="143" Body="&lt;p&gt;Is the greenhouse effect stronger in the ice covered area or in the equator?&#xA;Also is it stronger during winter or summer?&#xA;I am thinking it is stronger in the Ice covered area and during winter because of the bigger temperature difference but I can't fully support my answer.Any ideas?&lt;/p&gt;&#xA;" OwnerUserId="15721" LastEditorUserId="6258" LastEditDate="2019-06-15T11:22:06.760" LastActivityDate="2019-06-17T18:12:36.200" Title="When and where is the atmospheric greenhouse effect strongest?" Tags="|meteorology|homework|dynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17200" PostTypeId="1" CreationDate="2019-06-15T05:25:45.277" Score="1" ViewCount="223" Body="&lt;p&gt;I am new to GIS and just get the idea of slowness. I can understand why people need the slowness in GIS rather than just the reciprocal of velocity. However, I feel the definition of slowness is weird if we further introduce horizontal and vertical slowness. By intuition, the horizontal/vertical slowness should be the reciprocal of horizontal/vertical speed, and either horizontal or vertical wave speed should be smaller than the wave speed, due as a component. But from &lt;em&gt;&lt;a href=&quot;https://ocw.mit.edu/courses/earth-atmospheric-and-planetary-sciences/12-510-introduction-to-seismology-spring-2010/lecture-notes/lec5.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;MIT 12.510 Introduction to Seismology&lt;/a&gt;&lt;/em&gt;, it seems that wave speed is smaller than both horizontal wave speed and vertical wave speed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In summary, only one of the definitions for either wave speed or slowness can enjoy the regular decomposition property, is this true?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/e5zfc.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/e5zfc.png&quot; alt=&quot;screenshot from the reference&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17130" LastActivityDate="2019-06-15T13:23:51.833" Title="wave speed is smaller than both horizontal wave speed and vertical wave speed?" Tags="|seismology|waves|seismic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17201" PostTypeId="2" ParentId="17200" CreationDate="2019-06-15T11:51:13.637" Score="1" Body="&lt;p&gt;I don't know if I fully grasp your question; but I can confirm that slowness and velocity vectors are kind of weird things :-)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let me describe a simple example (and not worry too much about the mathematical details). If in the figure above, if you point your wave not diagonally but just straight down, what happens? Well, &lt;span class=&quot;math-container&quot;&gt;$dx$&lt;/span&gt; becomes infinitely large when the incidence angle becomes &lt;span class=&quot;math-container&quot;&gt;$i=0^\circ$&lt;/span&gt;, because there is no observable thing happening along the upper horizontal surface, the wave only moves down! At the same time, &lt;span class=&quot;math-container&quot;&gt;$dz$&lt;/span&gt; becomes exactly equal to &lt;span class=&quot;math-container&quot;&gt;$ds$&lt;/span&gt; when the incidence angle &lt;span class=&quot;math-container&quot;&gt;$i=0^\circ$&lt;/span&gt;. So, &lt;span class=&quot;math-container&quot;&gt;$dx=\infty$&lt;/span&gt; while &lt;span class=&quot;math-container&quot;&gt;$dz= ds$&lt;/span&gt;, right? I have drawn that in the figure below, for a monochromatic (single-frequency) wave, such that for all the 3 cases, the length of the vector &lt;span class=&quot;math-container&quot;&gt;$\vec{p}$&lt;/span&gt; is identical! I have added &lt;span class=&quot;math-container&quot;&gt;$c_x$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$c_z$&lt;/span&gt; as the &lt;em&gt;apparent&lt;/em&gt; velocities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TyQMA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TyQMA.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So for a wave moving straight down, the wave moves in 2D for a grand total distance of &lt;span class=&quot;math-container&quot;&gt;$ds$&lt;/span&gt;, it propagated 0 in the direction of &lt;span class=&quot;math-container&quot;&gt;$dx$&lt;/span&gt;, and &lt;span class=&quot;math-container&quot;&gt;$ds$&lt;/span&gt; in the direction of &lt;span class=&quot;math-container&quot;&gt;$dz$&lt;/span&gt;. Now your research already suggests that either of the following relations should  hold -- both basically expressions of the Pythagorean rule:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;dx^2 + dz^2 = ds^2, \tag{a}&#xA;$$&lt;/span&gt;&#xA;or &#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\frac{1}{dx^2} + \frac{1}{dz^2} = \frac{1}{ds^2} \tag{b}&#xA;$$&lt;/span&gt;&#xA;If we use our extreme example &lt;span class=&quot;math-container&quot;&gt;$dx=\infty$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$dz=ds$&lt;/span&gt;, then only equation b can hold (remember, &lt;span class=&quot;math-container&quot;&gt;$1/\infty=0$&lt;/span&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we multiply every term in equation &lt;span class=&quot;math-container&quot;&gt;$b$&lt;/span&gt; with &lt;span class=&quot;math-container&quot;&gt;$dt^2$&lt;/span&gt;, we get:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\frac{dt^2}{dx^2} + \frac{dt^2}{dz^2} = \frac{dt^2}{ds^2}, \tag{b'}&#xA;$$&lt;/span&gt;&#xA;or realizing that &lt;span class=&quot;math-container&quot;&gt;$dx/dt=c_x$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$dt/dx=1/c_x=p_x$&lt;/span&gt; we get:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;p_x^2 + p_z^2 = p^2 = \frac{1}{c^2}, \tag{b&quot;}&#xA;$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With those details out of the way, we have seen the following: &lt;span class=&quot;math-container&quot;&gt;$p_x=0$&lt;/span&gt; but &lt;span class=&quot;math-container&quot;&gt;$c_x=\infty$&lt;/span&gt;, and &lt;span class=&quot;math-container&quot;&gt;$p_z=1/c_z$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$c_z=c$&lt;/span&gt;. So we have found that both &lt;span class=&quot;math-container&quot;&gt;$\{c_x,c_z\}\geq c$&lt;/span&gt;, i.e., both &lt;em&gt;apparent&lt;/em&gt; velocities were greater than or equal to the original wave speed! On the other hand, &lt;span class=&quot;math-container&quot;&gt;$\{p_x,p_z\}\leq p$&lt;/span&gt;, i.e., the &lt;em&gt;apparent&lt;/em&gt; slowness components were less than or equal to the original slowness.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And that is the result that holds generally. The apparent velocity components are always equal to or greater than the original velocity; while the apparent slowness components are always equal to or less than the original slowness. This is why equations (b), (b') and (b&quot;) give the right decomposition rule, it's the only one where &lt;span class=&quot;math-container&quot;&gt;$p_x$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$p_y$&lt;/span&gt; are less than the full &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt;! This is why we can think of such a thing as a slowness vector &lt;span class=&quot;math-container&quot;&gt;$\vec{p}=(p_x,p_y)$&lt;/span&gt;, because the modulus of that vector &lt;span class=&quot;math-container&quot;&gt;$\lvert \vec{p} \rvert^2 = p_x^2+p_y^2$&lt;/span&gt; (which is eq. (b&quot;)) behaves exactly like a vector should!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope that maybe along the way I answered your question somehow? My apologies for the rather mathematical take on things, but it's the only way I ever understood slowness vectors!&lt;/p&gt;&#xA;" OwnerUserId="12155" LastEditorUserId="12155" LastEditDate="2019-06-15T13:23:51.833" LastActivityDate="2019-06-15T13:23:51.833" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17202" PostTypeId="2" ParentId="17183" CreationDate="2019-06-15T12:10:22.717" Score="1" Body="&lt;p&gt;See page 2 here for example: &lt;a href=&quot;https://pangea.stanford.edu/courses/gp262/Notes/8.SeismicVelocity.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://pangea.stanford.edu/courses/gp262/Notes/8.SeismicVelocity.pdf&lt;/a&gt; . &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What you refer to as Cp (as far as I can gather from your linked paper), is in the geophysics world generally referred to as the P-wave velocity (P stands for the primary/pressure/compressional wave; separating it from the S-wave which is the slower secondary/shear/transverse wave mode). It kind of depends on the specific mineralogy, compaction, depth, ... to determine exactly what the velocity is for any given rock. Note that the range of velocities is not particularly great (all values lie within one order of magnitude for typical rocks), so if your method is not particularly dependent on getting the P-wave velocity exactly right, you shouldn't have too much of a problem taking some average value for your rock! If, on the other hand, it is very sensitive to this value, you'll have to make an accurate measurement on your sample (which is not a trivial thing to do at all!).&lt;/p&gt;&#xA;" OwnerUserId="12155" LastActivityDate="2019-06-15T12:10:22.717" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17206" PostTypeId="1" CreationDate="2019-06-16T21:33:07.137" Score="2" ViewCount="171" Body="&lt;p&gt;So Potassium 40 decays in such a way that roughly 89% of it becomes Calcium 40 and 11% of it becomes Argon 40. When they list these figures are they implying that after 1 half-life, of the 50% of the material that decayed to daughter products, 89% of that 50% is Calcium 40 and 11% is Argon 40? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, does this mean that those will be the proportions of the daughter products in any given number of half lives?  Is the partitioning of the decay probability to 89% Calcium and 11% Argon  only observed at half-life intervals? Or is this constant throughout the decay chain, such as in between half-lives as well?  It should be constant (89% and 11%) throughout? Right? I had recently read some confusing literature on the subject and began to doubt my own understanding. &lt;/p&gt;&#xA;" OwnerUserId="14316" LastActivityDate="2019-06-28T09:41:11.367" Title="Potassum-Argon Dating and Proportions of Daughter Products in Potassium 40 Decay Channel" Tags="|geochemistry|radioactivity|dating|isotopic|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17207" PostTypeId="1" CreationDate="2019-06-17T02:41:39.903" Score="3" ViewCount="64" Body="&lt;p&gt;I have a question about the dynamics of westward propagating vortices. &#xA;In meteorology, the vorticity tendency is often used to explain the westward propagation of vortices (cyclonic circulation).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A good paper that utilizes this is as follows:&#xA;&lt;a href=&quot;https://journals.ametsoc.org/doi/full/10.1175/JCLI-D-14-00170.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://journals.ametsoc.org/doi/full/10.1175/JCLI-D-14-00170.1&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Development and Formation Mechanism of the Southeast Asian Winter Heavy Rainfall Events around the South China Sea. Part I: Formation and Propagation of Cold Surge Vortex&quot; by Chen et al. (2015).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This paper used the vorticity tendecy equation at 925hPa.However, I am wondering if it is correct to apply this at this level. Should this be more appropriate at 850hPa or higher levels, where terrain effects are minimal especially over the maritime continent?&lt;/p&gt;&#xA;" OwnerUserId="16927" LastActivityDate="2019-06-17T02:41:39.903" Title="Application of vorticity tendency equation" Tags="|meteorology|atmospheric-circulation|mesoscale-meteorology|dynamics|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17208" PostTypeId="2" ParentId="15028" CreationDate="2019-06-17T07:23:12.377" Score="1" Body="&lt;p&gt;Zech–Aslan energy statistic stands out as the most recommended metric&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Baseline setup and dataset The data that are used represent some&#xA;  aspects of the historical (recent past) and future climates at each&#xA;  grid cell of an array. The reference location corresponds to the grid&#xA;  cell for which analogs are sought, and candidate locations are all&#xA;  grid cells contained within the investigation domain, which includes&#xA;  the reference location itself. As presented in Fig. 1, the&#xA;  investigation domain is restricted to the following geographical&#xA;  limits: 358–508N, 608–1008W (excluding lake and ocean grid cells).&#xA;  When not otherwise stated, the reference location is the grid cell&#xA;  that includes the city of Montreal (centered at approximately 45.68N,&#xA;  73.58W and identified by a star in Fig. 1). For some calculations, 126 reference locations are used (also identified in Fig. 1). Each&#xA;  location’s climate is synthesized by a set of 90 values, accounting&#xA;  for values of three annual indicators over a 30-yr span. The&#xA;  historical and future periods extend over 1971–2000 and 2041–70,&#xA;  respectively.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pZJbz.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pZJbz.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://docsbay.net/an-assessment-of-six-dissimilarity-metrics-for-climate-analogs&quot; rel=&quot;nofollow noreferrer&quot;&gt;An Assessment of Six Dissimilarity Metrics for Climate Analogs&lt;/a&gt; by &lt;em&gt;PATRICK GRENIER&lt;/em&gt;&#xA;Ouranos Consortium, Montreal, Quebec, Canada &lt;/p&gt;&#xA;" OwnerUserId="17045" LastActivityDate="2019-06-17T07:23:12.377" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17209" PostTypeId="1" AcceptedAnswerId="17211" CreationDate="2019-06-17T09:07:26.697" Score="2" ViewCount="194" Body="&lt;p&gt;The tropical circulation paper by &lt;a href=&quot;https://iri.columbia.edu/~blyon/REFERENCES/P59.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gill (1980)&lt;/a&gt; approximates vertical velocity as the sum of pressure and diabatic heating terms (equation 2.5 at page 449).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the pressure is already a function of Q, what's the need of writing Q explicitly in this expression? Doesn't it double count p?&lt;/p&gt;&#xA;" OwnerUserId="11162" LastEditorUserId="11162" LastEditDate="2019-06-17T09:20:28.837" LastActivityDate="2019-06-20T09:48:35.393" Title="Presence of Diabatic heating term in the continuity equation" Tags="|meteorology|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="17210" PostTypeId="2" ParentId="17199" CreationDate="2019-06-17T18:01:04.517" Score="3" Body="&lt;p&gt;It is strongest in the arctics,most radiation from this area will be long wave infra red and long wave infra red is absorbed and reflected by the climate gases in the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A large part of the heat from the sun is reflected by snow and ice,But as the snow and ice melts more heat is absorbed by the water in the ocean the effect of this is larger in the arctic(floatng ice)than it is in the antarctic(more ice on land and takes longer to melt)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Link &lt;a href=&quot;https://en.wikipedia.org/wiki/Infrared&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Infrared&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the areas closer to equator the heating is higher so a larger amount of the radiation will be at a shorter wavelenght,And a larger portion of this will escape to space and not be stoped by the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The equator will heat up less than the arctics simply as a result of the shorter wavelenght in infrared radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The winters will warm faster than the summers in the arctics and this too is a result of the longwave infrared radiation in the winter and the shorter wavelenght(hot summer).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The nights do warm faster than the days too as a result of longwave radiation at night(colder)and shorter wavelenght in the day(hotter)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The earth will keep getting warmer until a new equiriblium is reached where incomming and outgoing heat will be in balance(if we stop the realease of greenhouse gasses today the earth will keep on getting hotter for atleast 50-100 years).&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6258" LastEditDate="2019-06-17T18:12:36.200" LastActivityDate="2019-06-17T18:12:36.200" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17211" PostTypeId="2" ParentId="17209" CreationDate="2019-06-18T10:26:35.650" Score="2" Body="&lt;p&gt;In the book - &lt;a href=&quot;https://www.elsevier.com/books/atmosphere-ocean-dynamics/gill/978-0-12-283522-3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atmosphere-Ocean Dynamics, Volume 30 &lt;/a&gt; the author AE Gill defines the perturbation pressure in the paper that OP references as the following.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider a pressure of a reference system (ocean/atmosphere at rest) and let us call it &#xA;    &lt;span class=&quot;math-container&quot;&gt;$$p_0$$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It must be noted that a real atmosphere is never at rest and so we consider deviations from the reference system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since we are dealing with a vertical pressure gradient for OP's equation(2.5)(the gravitational force matches the vertical pressure gradient for hydrostatic large scale circulations) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$p_0$$&lt;/span&gt; is a function of &lt;span class=&quot;math-container&quot;&gt;$z$&lt;/span&gt; where z is the height coordinate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then the perturbation pressure &lt;span class=&quot;math-container&quot;&gt;$p'$&lt;/span&gt; is defined in the following way&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$p = p_0(z) + p' $$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if you add the perturbation pressure to the reference pressure we get the deviation from the reference system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly a perturbation density can be defined in the following way&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\rho = \rho_0(z) + \rho' $$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The basis for doing this comes from classical mechanics &lt;a href=&quot;https://en.wikipedia.org/wiki/Perturbation_theory&quot; rel=&quot;nofollow noreferrer&quot;&gt;Perturbation Theory&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question is why is this being done ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We are looking for solutions that are basically of a oscillatory nature. So in effect this gets rid of the non linear cross terms for which no oscillatory solution exists. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the specific case of 2.5 from the paper you referenced in addition to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Brunt%E2%80%93V%C3%A4is%C3%A4l%C3%A4_frequency&quot; rel=&quot;nofollow noreferrer&quot;&gt;Brunt–Väisälä frequency&lt;/a&gt; one needs to consider a &quot;buoyancy forcing&quot; especially in the tropics because of the large contributions from diabatic heating. We are essentially talking of an &lt;a href=&quot;https://en.wikipedia.org/wiki/Thermodynamic_system#Open_system&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;open system&quot;&lt;/a&gt; where in addition to adiabatic &quot;work&quot; being done you also have to account for heat exchange between a system and the ambient environment. In reality this is assumed as &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Pseudoadiabatic_process&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;pseudoadiabatic&quot; process &lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then the question is how is the heating rate modeled ? In the AE Gill book this is given by the following equation &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ Q_H =  -L_V \frac{Dq_w}{Dt}$$&lt;/span&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$L_v$&lt;/span&gt; is the latent heat of vaporization and &lt;span class=&quot;math-container&quot;&gt;$q_w$&lt;/span&gt; is the saturation humidity where the word saturation means the saturation water vapor mixing ratios. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Equation (2.5) from OP's paper is derived in Gill's book and is present in the 9th chapter(9.13.7) and will not be derived here but will be stated as is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\omega_n = \frac{\partial \widetilde \eta}{\partial t} + \widetilde b_n$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here &lt;span class=&quot;math-container&quot;&gt;$\widetilde \eta $&lt;/span&gt; is the vertical coordinate(in OP's paper the vertical coordinate is pressure) and &lt;span class=&quot;math-container&quot;&gt;$b_n$&lt;/span&gt; is the rate of change of buoyancy  per unit volume. This form is known as the buoyancy forced &lt;a href=&quot;https://en.wikipedia.org/wiki/Shallow_water_equations&quot; rel=&quot;nofollow noreferrer&quot;&gt;Shallow water equations&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One can get more details about the perturbation theory for the atmosphere by looking at this link - &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0074614208605239&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atmospheric Oscillations: Linear Perturbation Theory&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly if you want horizontal pressure perturbations you model the reference pressure as a function of x and y and then consider deviations thereof. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Useful reading&lt;/strong&gt;&#xA;&lt;a href=&quot;https://physics.stackexchange.com/questions/427000/what-is-the-meaning-of-pressure-in-the-navier-stokes-equation?rq=1&quot;&gt;What is the meaning of pressure in the Navier-Stokes equation?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-06-20T09:48:35.393" LastActivityDate="2019-06-20T09:48:35.393" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="17212" PostTypeId="1" CreationDate="2019-06-18T15:51:28.293" Score="3" ViewCount="96" Body="&lt;p&gt;I've been doing some wikipedia binging and it's come to my realization that it may be in the Earth's best interest to raise the world oyster population as quickly as possible. The basis for this is for several reasons:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;[They hold] promise for relieving pressure on land-based protein sources.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;also,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;[They] provide shoreline protection and sediment stabilization,&#xA;  nutrient cycling and sequestration, and habitat for other organisms.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and most importantly:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;sources state that a single oyster can filter 24–96 liters a day (1–4 liters per hour). With 750,000 oysters in one acre, 18,000,000-72,000,000 liters of water can be filtered, removing most forms of particulate matter suspended in the water column.&#xA;  (&lt;a href=&quot;https://en.wikipedia.org/wiki/Oyster_farming#Environmental_impact&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What I'm curious about, however, is the potential downstream impacts of the overpopulation of oysters.&#xA;They seem to have so many ecological benefits, I'd like to see if there's a hard detriment to everyone breeding thousands of oysters in their free time to help the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I'm particularly concerned about is other filter feeders that may become threatened by a strong prevalence of the oyster population.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To summarize my question; is this a reasonable solution, and what potential risks exist should the world try to greatly increase the oyster populations where they exist currently already?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;As @Fred pointed out in the comments, precautions would/should be taken to ensure endemic oysters are used to be as minimally invasive as possible, and responsibly bred for biodiversity to prevent viral catastrophe.&lt;/p&gt;&#xA;" OwnerUserId="17150" LastEditorUserId="17150" LastEditDate="2019-11-04T16:24:01.917" LastActivityDate="2019-11-04T16:31:47.633" Title="Quickly breeding oysters to combat oceanic pollution?" Tags="|climate-change|oceanography|environmental-protection|ecology|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="17213" PostTypeId="1" CreationDate="2019-06-18T17:28:28.763" Score="1" ViewCount="52" Body="&lt;p&gt;I am looking for a small-scale isobaric chart, which encompasses central Africa. I am interested in the time span of the past few months. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do you know where to find it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks &lt;/p&gt;&#xA;" OwnerUserId="17152" LastActivityDate="2019-11-29T13:02:20.347" Title="Historical isobaric charts?" Tags="|meteorology|barometric-pressure|database|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17214" PostTypeId="1" AcceptedAnswerId="17224" CreationDate="2019-06-18T19:47:00.293" Score="3" ViewCount="81" Body="&lt;p&gt;Last weekend I was in Xınalıq(the village in Azerbaijan) and found this snail shell. I am wondering how old is this?&lt;a href=&quot;https://i.stack.imgur.com/d4pC3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/d4pC3.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17155" LastActivityDate="2019-06-25T03:32:10.197" Title="How older is this snail shell possible could be?" Tags="|geology|paleontology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17215" PostTypeId="2" ParentId="16977" CreationDate="2019-06-18T22:17:10.880" Score="1" Body="&lt;p&gt;I suppose the answer depends on total lifecycle emissions as well as landfill environmental cost.&#xA;For plastic I assume PP or PETE. &#xA;For styrofoam production is based on polystyrene so some styrene emissions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For lifecycle costs, emissions for manufacturing as well as energy (coal or gas power plant) need to be considered. Also are either recycled and in what proportion and does that impact lifestyle costs. Not an easy question, or one I can quantify. For simplicity l would look at two questions- production emissions of the actual cup and or feedstocks and recyclability of each cup.  According to this link styrofoam is not recyclable so I would guess plastic is not as bad. &#xA;&lt;a href=&quot;https://sciencing.com/styrofoam-vs-plastic-cups-12400119.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://sciencing.com/styrofoam-vs-plastic-cups-12400119.html&lt;/a&gt;&#xA;Here it says polystyrene is usually not recyclable locally. &lt;a href=&quot;https://science.howstuffworks.com/environmental/green-science/polystyrene-recycling.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://science.howstuffworks.com/environmental/green-science/polystyrene-recycling.htm&lt;/a&gt;&#xA;Here is a different perspective whose author suggests styrofoam lifecycle cost could be lower compared to some other options:&#xA;&lt;a href=&quot;https://daily.jstor.org/is-the-30-year-long-styrofoam-war-nearing-its-end/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://daily.jstor.org/is-the-30-year-long-styrofoam-war-nearing-its-end/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not exactly an answer but at least a start&lt;/p&gt;&#xA;" OwnerUserId="16983" LastEditorUserId="16983" LastEditDate="2019-06-18T22:34:23.013" LastActivityDate="2019-06-18T22:34:23.013" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17216" PostTypeId="1" AcceptedAnswerId="17222" CreationDate="2019-06-18T22:54:44.430" Score="1" ViewCount="379" Body="&lt;p&gt;I am on my second vehicle that I have stopped changing my oil after the car has been broke in or around 90k. The first car I made it 400k miles before the rear end went out. The second car I'm at 130k with no oil change from 90k and runs just as good when I got it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does not changing the oil decrease the vehicles carbon footprint then changing it? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I watched the Discovery Channel and a Japanese Engineer said their engines are built efficiently enough not to need an oil change ever. I still add an oil stabilizer like Lucas every 4th quart when I top it off. I am not interested whether it is bad for an engine to do so. I just want to know if it more environmentally friendly not to change the oil?&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2019-06-18T23:38:48.790" LastActivityDate="2019-06-19T05:36:57.037" Title="What is the Carbon Footprint of not changing car oil?" Tags="|air-pollution|human-influence|environmental-protection|economic-geology|carbon|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17217" PostTypeId="2" ParentId="8716" CreationDate="2019-06-19T01:45:27.360" Score="2" Body="&lt;p&gt;Areas of high elevation, such as mountain ranges, often drain the air of its moisture. As the air rises up the mountain, it cools. As the air cools, it loses its ability to hold water. The water then condenses out of the air and falls as precipitation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The high altitudes of mountains often receive a significant amount of precipitation. Often, this precipitation falls in the form of snow, which is why many high mountain peaks are always covered in snow. In mountains near the equator, the constantly high levels of humidity form what is called a &quot;cloud forest.&quot; Cloud forests are habitats that feature numerous mosses, algae and epiphytic plants; often, these plants are covered in water for most of the day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While the top of the mountain may receive abundant rainfall, mountains often remain dry on the down-wind side. This is called the &quot;rain shadow effect,&quot; and it causes the downwind side of the mountain to remain dry for most of the year. One of the best examples of this phenomenon is created by the Himalayan Mountains. As the warm, moist air blows from the Indian Ocean, it flies up the side of the Himalayas. Most of the rain falls on the south side of the mountains, and the area on the north side of the mountains remains dry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This actual case explain more details &lt;a href=&quot;https://docsbay.net/a-preliminary-analysis-of-the-relationship-between-precipitation-variation-trends-and-altitude-in-china&quot; rel=&quot;nofollow noreferrer&quot;&gt;A Preliminary Analysis of the Relationship between Precipitation Variation Trends and Altitude in China&lt;/a&gt; by ATMOSPHERIC AND OCEANIC SCIENCE LETTERS, 2011, VOL. 4, NO. 1, 4146 &lt;/p&gt;&#xA;" OwnerUserId="17045" LastActivityDate="2019-06-19T01:45:27.360" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17221" PostTypeId="1" AcceptedAnswerId="17225" CreationDate="2019-06-19T03:30:01.643" Score="12" ViewCount="579" Body="&lt;p&gt;The New York Times article &lt;a href=&quot;https://www.nytimes.com/2019/06/18/science/shipworm-rocks-sand.html&quot; rel=&quot;noreferrer&quot;&gt;This Creature Eats Stone. Sand Comes Out the Other End.&lt;/a&gt; describes the shipworm &lt;em&gt;Lithoredo abatanica&lt;/em&gt;, an organism that appears to &quot;eat solid rock&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It links to the item in Science &lt;a href=&quot;https://www.sciencemag.org/news/2019/06/rock-eating-worm-could-change-course-rivers&quot; rel=&quot;noreferrer&quot;&gt;This rock-eating ‘worm’ could change the course of rivers&lt;/a&gt; which then links to the YouTube video &lt;a href=&quot;https://youtu.be/K220SUWJ73w&quot; rel=&quot;noreferrer&quot;&gt;Snippet: Shipworms that eat rocks&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The video shows how easily this rock can be split apart.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The rock was taken from the bottom of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Abatan_River&quot; rel=&quot;noreferrer&quot;&gt;Abatan River&lt;/a&gt; on Bohol Island, in the Philippines.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Is it possible from the images, descriptions, and video to say something about this rock? Is it a kind of sandstone? It looks fairly loosely held-together and porous.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Images from &lt;a href=&quot;https://www.nytimes.com/2019/06/18/science/shipworm-rocks-sand.html&quot; rel=&quot;noreferrer&quot;&gt;NYTimes&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/mjmb5.jpg&quot; alt=&quot;Lithoredo abatanica, from inside a piece of rock&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; Lithoredo abatanica, from inside a piece of rock. CreditM arvin A. Altamia and Reuben Shipway (click for full size)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;below:&lt;/strong&gt; Two large burrows in rock made by shipworms. Credit Marvin A. Altamia and Reuben Shipway (click for full size)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/YoGJE.jpg&quot; alt=&quot;Two large burrows in rock made by shipworms&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorDisplayName="user12525" LastEditDate="2019-08-27T10:55:50.240" LastActivityDate="2019-12-13T14:02:34.587" Title="What kind of rock is this being eaten by a rock-eating worm?" Tags="|petrology|paleontology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17222" PostTypeId="2" ParentId="17216" CreationDate="2019-06-19T05:36:57.037" Score="2" Body="&lt;p&gt;This is an interesting question, and a life cycle emissions analysis can give a pretty good answer.  Obviously there are a lot of variables, so some basic assumptions have to be made.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We start with the CO2 equivalent emissions from building and driving a car over its lifetime.  There are various analyses out there, but &lt;a href=&quot;https://www.lowcvp.org.uk/assets/workingdocuments/MC-P-11-15a%20Lifecycle%20emissions%20report.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; is one that I found which gives the following values for a typical gasoline powered automobile over a &quot;typical&quot; lifetime of 150,000 km (93,000 miles): 24,000 kg of CO2e emissions total, of which 5600 kg is from the fabrication of the car.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the oil, I found &lt;a href=&quot;https://pubs.acs.org/doi/pdf/10.1021/sc400182k&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;, which gives a range of 2.5 to 13 kg CO2e per gallon of motor oil.  The lower value assumes the new oil is made from recycled oil, and the waste oil is sent to a recycler.  The higher value assumes the new oil is not from a recycled source, and the waste oil is not recycled.  For the most extreme case, we can assume virgin oil, and assume the oil is changed every 3000 miles, and that the car holds 4 quarts (1 gallon).  That makes 31 oil changes in the car's lifetime, which gives 403 kg of CO2e from oil changes.  Another perfectly reasonable value might be to assume recycling and assume an oil change every 7000 miles which results in 33 kg CO2e emissions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the oil changes are contributing something in the 30 to 400 kg range over the life of the car, compared with 24,000 kg from building and driving the car.  Skipping all oil changes in the most extreme case results in less than 2% reduction in total CO2e emissions.  You can get almost exactly the same result by changing the oil every 7000 miles instead of every 3000, and by using recycled oil and making sure that your used oil is recycled.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even though you're not asking about it, I have to add that I think you have been exceptionally lucky if you drove 400,000 miles without changing the oil.  I don't think you should expect that result again.  And note that the emissions associated with building a car are 5600 kg - 10 to 100 times greater than the emissions contributed by changing the oil.  If you don't change the oil in any car again for your entire life, and end up ruining just one car as a result, you will cause far more emissions than you saved.&lt;/p&gt;&#xA;" OwnerUserId="8163" LastActivityDate="2019-06-19T05:36:57.037" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17224" PostTypeId="2" ParentId="17214" CreationDate="2019-06-19T11:50:05.457" Score="4" Body="&lt;p&gt;That's not a snail &lt;em&gt;per se&lt;/em&gt; it's the shell of an &lt;a href=&quot;https://en.wikipedia.org/wiki/Ammonoidea&quot; rel=&quot;nofollow noreferrer&quot;&gt;ammonite&lt;/a&gt; which is more like a squid with an external shell than anything else I can think to compare it to. They went extinct with the dinosaurs so it's at least 65 million years old and could be much older.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2019-06-19T11:50:05.457" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17225" PostTypeId="2" ParentId="17221" CreationDate="2019-06-19T12:26:03.630" Score="15" Body="&lt;p&gt;thank you for your interest in the article. I'm the lead author on this paper (Shipway) and I happened to come across your post when looking through all the media stories on this animal. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer your question; yes, you're right, the rock is a calcareous sandstone. It was easy to split, partly because it is a naturally soft rock and partly because the shipworms had weakened the structure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope that answered your question.&lt;/p&gt;&#xA;" OwnerUserId="17159" LastActivityDate="2019-06-19T12:26:03.630" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17226" PostTypeId="1" CreationDate="2019-06-17T10:35:47.097" Score="4" ViewCount="147" Body="&lt;p&gt;For every asteroid or meteorite that hits dry land, two hit the sea. If a &lt;a href=&quot;https://en.wikipedia.org/wiki/Manicouagan_Reservoir#Impact_crater&quot; rel=&quot;nofollow noreferrer&quot;&gt;Manicouagan&lt;/a&gt;-sized asteroid struck the deep ocean (but not above a trench),how would the H2O vapour, chlorine, iodine bromine and other elements affect the climate, and for how long? Also, if it had thousands of feet of water to penetrate, would it leave a large crater on the sea bed? For sure it would create massive tsunamis, so is there any evidence for these in the geological record? The Manicouagan crater is far from being the largest on Earth, but is only slightly smaller than the &lt;a href=&quot;https://en.wikipedia.org/wiki/Chicxulub_crater&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chicxulub&lt;/a&gt; example. It was caused by an asteroid 5km in diameter traveling at 25km per second, though friction with the atmosphere probably reduced this slightly before it struck the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Manicouagan, however, is just an example, we are talking here about a hypothetical asteroid of this size striking the deep ocean. Don't be misled by the word hypothetical; given the number of large impacts which have happened on land there must have been some which landed in deep ocean. How deep? Let's call it 6,000 feet, which is nowhere near a record depth.&lt;/p&gt;&#xA;" OwnerUserId="17166" OwnerDisplayName="Michael Walsby" LastEditorUserId="6031" LastEditDate="2019-06-20T09:32:20.500" LastActivityDate="2019-08-13T19:32:05.730" Title="Climate consequences of very large asteroids striking the Deep Ocean" Tags="|geology|climate|impacts|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17232" PostTypeId="2" ParentId="17173" CreationDate="2019-06-20T12:59:20.353" Score="2" Body="&lt;p&gt;As you probably realise, the Earth's early atmosphere was mainly composed of CO2, as are the atmospheres of Mars and Venus to this very day. You are right in thinking that most of this CO2 was removed by biological activity; if all the earth's fossil fuels and limestone rocks were converted back into CO2, we would have an atmosphere similar to that which existed nearly 4 billion years ago. It was this same biological activity which built up the oxygen level to its present 21 percent. The process continues right up to the present day. The CO2 content of the atmosphere is to some extent self regulating: the higher the levels, the more vigorously plants and photosynthetic micro-organisms grow, extracting more and more carbon dioxide from the atmosphere, but this natural process could be swamped if the build-up of CO2 exceeded the capacity of plants to remove it. It is not generally known that algae and phytoplankton in the sea remove more CO2 and generate more oxygen than all the rainforests.  &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-06-20T12:59:20.353" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17234" PostTypeId="1" CreationDate="2019-06-19T19:17:57.463" Score="5" ViewCount="141" Body="&lt;p&gt;As the sun gets brighter, the oceans are expected to evaporate by the next billion years or so (the vapor slowly gets stripped off into space). The salt, which is less dense than most rocks, will be left behind. Then wait another couple of billion years. Most rocks melt at a higher temperature than sea salt: basalt melts at around 1000C, quartz melts at 1713C, but NaCl melts at only 801C (adding other salts will lower this). So will a tangerine sun loom large over red-hot waves softly breaking on abyssal beaches?&lt;/p&gt;&#xA;" OwnerUserId="8476" OwnerDisplayName="Kevin Kostlan" LastEditorUserId="725" LastEditDate="2019-06-21T10:03:38.237" LastActivityDate="2019-06-21T10:03:38.237" Title="Molten salt seas on the future Earth" Tags="|oceanography|geochemistry|earth-history|igneous|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17235" PostTypeId="2" ParentId="17234" CreationDate="2019-06-19T20:21:00.803" Score="1" Body="&lt;p&gt;I very much doubt whether this is going to happen within the next billion years, but something like it is bound to happen one day. Our sister planet Venus has already reached a surface temperature of 400C,which has boiled off the oceans but is not hot enough to melt salt. There should be some salt deposits there (even Ceres has some),but perhaps they are buried, as is much of the evaporite salt on Earth. To cut a long story short, in several billion years time the Earth will be like a super-hot Venus, but with the occasional pond or lake of molten salt rather than oceans of it, and an enormous tangerine sun will indeed loom large in the sky. Mankind will have gone to join the dinosaurs billions of years earlier, so there's no need to worry about it.&lt;/p&gt;&#xA;" OwnerUserId="17166" OwnerDisplayName="Michael Walsby" LastActivityDate="2019-06-19T20:21:00.803" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17237" PostTypeId="1" AcceptedAnswerId="17240" CreationDate="2019-06-20T21:51:51.277" Score="9" ViewCount="804" Body="&lt;p&gt;From a &lt;a href=&quot;https://earthscience.stackexchange.com/questions/6515/in-the-northern-hemisphere-only-what-percentage-of-the-surface-is-land&quot;&gt;previous question&lt;/a&gt;, around 40% of the northern hemisphere is land. Would there be a plane splitting the earth into two equal parts, where in one part there are more land than ocean?&lt;/p&gt;&#xA;" OwnerUserId="17174" LastActivityDate="2019-06-23T11:27:20.967" Title="Is there a hemisphere where there's more land than ocean?" Tags="|geography|land-surface|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17238" PostTypeId="2" ParentId="17234" CreationDate="2019-06-21T10:03:03.490" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;So will a tangerine sun loom large over red-hot waves softly breaking on abyssal beaches?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Probably not. Interesting question, and one might think that yes - you could melt the evaporite deposits that will be left after all the water is gone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem is that molten salts are extremely reactive materials. They will corrode any rock they get into contact with. As most rocks on the ocean floor are silicates (basalts etc) you will just get chloride-silicate minerals. For example, the reaction between halite and nepheline (a fairly common silicate mineral) will lead to the formation of sodalite (another fairly common mineral):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{6NaAlSiO4 + 2NaCl = Na8(SiAl)6O24Cl2}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's a long list of known &lt;a href=&quot;https://www.mindat.org/chemsearch.php?cform_is_valid=1&amp;amp;inc=Si%2CCl%2C&amp;amp;exc=H%2C&amp;amp;class=0&amp;amp;sub=Search%20Minerals&amp;amp;cf_pager_page=1&quot; rel=&quot;noreferrer&quot;&gt;chloride-silicate minerals&lt;/a&gt;, and for a more realistic salt–basalt reaction the products can be things like &lt;a href=&quot;https://www.mindat.org/min-29331.html&quot; rel=&quot;noreferrer&quot;&gt;scapolite&lt;/a&gt;, &lt;a href=&quot;https://www.mindat.org/min-46164.html&quot; rel=&quot;noreferrer&quot;&gt;adrianite&lt;/a&gt;, or &lt;a href=&quot;https://www.mindat.org/min-4226.html&quot; rel=&quot;noreferrer&quot;&gt;wadalite&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You will most likely end up with no salt, overlying a somewhat thin (metres?) layer of these silicate-chlorides. It could be that in some points you might have ephemeral pools of liquid salt, or in places where the chloride-silicate layer is thick enough to effectively isolate the liquid salt from the silicate rocks below, but those will probably be negligible features on the scale of the planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One final comment:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;quartz melts at 1713C&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In isolation. When quartz is mixed with other things (like feldspars in a granite), it melts at a lower, &lt;a href=&quot;https://en.wikipedia.org/wiki/Eutectic_system&quot; rel=&quot;noreferrer&quot;&gt;eutectic&lt;/a&gt;, temperature.  See related question &lt;a href=&quot;https://earthscience.stackexchange.com/a/2742/725&quot;&gt;one&lt;/a&gt; and &lt;a href=&quot;https://earthscience.stackexchange.com/a/14208/725&quot;&gt;two&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-06-21T10:03:03.490" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17240" PostTypeId="2" ParentId="17237" CreationDate="2019-06-21T17:01:37.893" Score="6" Body="&lt;p&gt;The total land area of earth is approximately 29%. So, in order to have a hemisphere with more land than water, out of 29% of total land area we need to have at least 25% of it concentrated in that hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now for the ease of understanding, what does 25/29 of total land area means? It approximates to 86% of the total continental surface area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Area of percentage &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Asia (including the Middle East)- 30.0%&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Africa - 20.3%&lt;/p&gt;&#xA;&#xA;&lt;p&gt;North America - 16.3%&lt;/p&gt;&#xA;&#xA;&lt;p&gt;South America - 12.0%&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Antarctica - 8.9%&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Europe - 6.7%&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Australia (plus Oceania) - 5.2%&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now on analyzing this, it's possible to conclude you won't be able to get such a hemisphere using a plane along the longitudes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you try to create a hemisphere using a plane that cuts through 60˚S and 60˚N latitudes, you might be able to have most the major land together areas except Antartica and Australia and some parts of Africa in it. Still, it won't be enough to have more than half of that hemisphere with land covering it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, my conclusion is it's not possible to come up with such a hemisphere. :) &lt;/p&gt;&#xA;" OwnerUserId="17178" LastActivityDate="2019-06-21T17:01:37.893" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17242" PostTypeId="2" ParentId="17098" CreationDate="2019-06-21T17:27:55.833" Score="2" Body="&lt;p&gt;The maximum vapor pressure in air is a function of the temperature and not of the total pressure. So when you humidify air at 12°C you get a maximum vapor pressure of approximately 1.4 kPa. However, when the air is humidified at 140 kPa the vapor pressure is still only 1.4 kPa. Therefore, you have a water/air ratio of 1.4/140= 1%. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, for every mol of water, you will have 100 mol of air. So when the total pressure drops to 100 kPa, the mol/volume fractions will not change. This is also valid for the vapor pressure ratio. Therefore, in this case the vapor pressure will still be 1% of the total pressure. Thus, the vapor pressure will only be 1.0 kPa at a total pressure of 100 kPa.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore, to &quot;correct&quot; an &quot;under-pressure&quot; reading you will need to multiply your &quot;under pressure&quot; reading by (101.3 kPa)/(P_actual), where P_actual is your actual total pressure in kPa.&lt;/p&gt;&#xA;" OwnerUserId="17014" LastActivityDate="2019-06-21T17:27:55.833" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17244" PostTypeId="1" AcceptedAnswerId="17245" CreationDate="2019-06-21T19:38:21.640" Score="26" ViewCount="10458" Body="&lt;p&gt;The picture below shows an imaginary line on the globe which crosses the Pacific Ocean and works as a rough separator of the Eastern and Western hemispheres.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is this line called in English? I'm trying to find the history behind its funny shape.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WIGv4.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WIGv4.png&quot; alt=&quot;li&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17181" LastEditorUserId="543" LastEditDate="2019-06-22T03:33:49.877" LastActivityDate="2019-06-22T12:39:23.993" Title="What is the line crossing the Pacific Ocean that is shown on maps?" Tags="|geography|mapping|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17245" PostTypeId="2" ParentId="17244" CreationDate="2019-06-21T19:54:19.300" Score="50" Body="&lt;p&gt;It's the &lt;a href=&quot;https://en.wikipedia.org/wiki/International_Date_Line&quot; rel=&quot;noreferrer&quot;&gt;international date line&lt;/a&gt; and marks the boundary between the time zones that are +12 and -12 hours from UTC / Greenwich. It should follow the +/-180 degree meridian line, but zigs and zags to include territories or islands within a &quot;day&quot; thus the Aleutians islands are in the same time zone as the Hawaiian islands. &lt;/p&gt;&#xA;" OwnerUserId="1339" LastActivityDate="2019-06-21T19:54:19.300" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17246" PostTypeId="2" ParentId="17237" CreationDate="2019-06-21T21:51:16.680" Score="12" Body="&lt;p&gt;I wrote a little Matlab script to estimate this approximatively. Here is the result: colour denotes the total land area inside the hemisphere centred on a particular surface point. The red point is the maximum.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/JwSNr.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JwSNr.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This gives me a maximum for the hemisphere centred on 1.7582°W longitude and 40.7692°N latitude, roughly in Guadalajara, Spain. If I calculated right this is 81% of all land, with 23.37% land area on the hemisphere (and 5.83% on the other hemisphere). So the answer to the question is no, there is no hemisphere with more land than ocean. There isn't even one with more than half land.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vzXJJ.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vzXJJ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/Lgyet.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Lgyet.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/vmZGC.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vmZGC.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Updated 2019-06-23 with higher resolution estimation, which moved the point south a bit.)&lt;/p&gt;&#xA;" OwnerUserId="12421" LastEditorUserId="12421" LastEditDate="2019-06-23T11:27:20.967" LastActivityDate="2019-06-23T11:27:20.967" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17248" PostTypeId="2" ParentId="17244" CreationDate="2019-06-22T08:59:35.303" Score="39" Body="&lt;p&gt;Mkennedy's answer is right at identifying that line as the international date line and explaining how it works. However, I'd like to add on the main weird points of the line. North to south:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the Bering sea, the line bends eastward to include all Russia in the same side, and then it bends westward to include the Aleutian islands on the same side as Alaska and the rest of the United States. Interestingly, until the Alaska purchase in 1867, the line was located a lot more to the east to give Alaska the same date than the rest of Russia. Thus, until then the IDL crossed a continent and you could change date just by walking - nowadays the only land crossed by the IDL is Antarctica.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other weird path in middle of the Pacific Ocean is Kiribati. Despite having a small land surface, Kiribati is a large country when it comes to distance between its extreme points, because it's made of a lot of tiny islands scattered over a large sea area that spans several time zones. Kiribati was formed in 1979 from British and American colonies on both sides of the IDL. It continued to be this way until 1994 when the IDL was shifted eastwards to include the whole country in the same side. Incidentally, that made some islands in eastern Kiribati the first place to welcome the year 2000, which attracted attention and some tourism at that time.&lt;/p&gt;&#xA;" OwnerUserId="6550" LastEditorUserId="17189" LastEditDate="2019-06-22T12:39:23.993" LastActivityDate="2019-06-22T12:39:23.993" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="17250" PostTypeId="1" CreationDate="2019-06-22T11:34:49.760" Score="3" ViewCount="293" Body="&lt;p&gt;Some geologists say there were times between 770 million years BP and 630 million years BP when ice ages were so profound that the Arctic and Antarctic ice caps met at the equator. This is called the Snowball Earth theory. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although at the beginning of this period, there were, so far as we know, no advanced invertebrates able to leave easily identifiable fossils, there were by the end of it, so how were they able to thrive and evolve under the ice? There must also have been early marine plants under the ice (there were none on land), so how did they survive? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main evidence for this glaciation is apparent glacial markings on rocks in S.Africa and Australia, Couldn't there be other explanations for these apparent glacier tracks, apart from Snowball Earth? For example, Australia may have been closer to the S.Pole then, and some of the locations where evidence of glaciers was found might have been much higher above sea level than they are today.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="6703" LastEditDate="2019-06-26T13:12:03.273" LastActivityDate="2019-07-26T16:03:00.440" Title="How Good is The Evidence For Snowball Earth?" Tags="|earth-history|fossils|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17251" PostTypeId="2" ParentId="834" CreationDate="2019-06-22T15:34:42.477" Score="-1" Body="&lt;p&gt;Re: Seamounts vs land based Mountains&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mt Everest is the highest land based mountain at 8,800m above sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mauna Kea seems the highest Seamount at 10,100m with 4,200m above sea level and therefore about 6,000m below sea level. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A typical Seamount is 1,000 to 4,000m which seems similar to land based mtns.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Somewhat avoiding debate over whether above of below sea-level Mauna Kea still seems the highest Seamount.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another item of interest is what is the deepest ocean trench and it seems to be the Mariana Trench at -10,994m below sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Mariana Trench or Marianas Trench is located in the western Pacific Ocean about 200 kilometres (124 mi) east of the Mariana Islands, and has the deepest natural trench in the world. Elevation: -10,994 m.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Greg W   &lt;/p&gt;&#xA;" OwnerUserId="17192" LastActivityDate="2019-06-22T15:34:42.477" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17252" PostTypeId="2" ParentId="15295" CreationDate="2019-06-22T17:51:01.193" Score="1" Body="&lt;p&gt;As I see it, the Earth is well oriented, but due to (over)simplification the drawing of the geographical features may be misleading. The aspects that show that the North Pole is not upwards but tilted to the right are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The Mediterranean sea extends basically in an East-West direction. The (simplified) Mediterranean here is clearly tilted and not horizontal.&lt;/li&gt;&#xA;&lt;li&gt;The white mass that looks as sea ice to Fred is neither the Arctic Ocean nor the Denmark Strait, but it's actually Greenland. The green masses at its left are not Greenland but a sketchy version of Baffin Island and the northeastern part of Labrador Peninsula. Seen this way, Greenland is to the right to where it would be if Earth was upright.&lt;/li&gt;&#xA;&lt;li&gt;The western coast of Europe. The Iberian Peninsula and the Scandinavian Peninsulas are clearly visible in the map, allowing to draw a line between them. That line is clearly tilted compared with how it would be in a map.&lt;/li&gt;&#xA;&lt;li&gt;The equator itself can be traced from the Gulf of Guinea (barely noticeably under the red ecliptic plane) to the North coast of Brazil, and it results to be clearly tilted. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Therefore, the drawing is not wrong, but just very sketchy.&lt;/p&gt;&#xA;" OwnerUserId="6550" LastEditorUserId="6550" LastEditDate="2019-06-23T15:38:40.370" LastActivityDate="2019-06-23T15:38:40.370" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17253" PostTypeId="1" AcceptedAnswerId="17254" CreationDate="2019-06-22T17:51:34.363" Score="2" ViewCount="338" Body="&lt;p&gt;We know that the composition of the crust is SiAl and SiMa and the one of mantle is mostly ophiolites, but why? Which are the geological processes that make this difference exist? &lt;/p&gt;&#xA;" OwnerUserId="17194" LastActivityDate="2024-01-26T14:21:25.983" Title="How is the difference in crust and mantle composition explained?" Tags="|geology|geochemistry|plate-tectonics|petrology|mantle|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17254" PostTypeId="2" ParentId="17253" CreationDate="2019-06-22T20:31:48.587" Score="2" Body="&lt;p&gt;Generally speaking , Earth's interior is classified using two models, the mechanical and chemical model. In the chemical model, the layers are crust, mantle and core. These layers organized while Earth started to cool after formation at the stage known as &lt;strong&gt;planetary differentiation&lt;/strong&gt;. Heavier materials such as &lt;em&gt;Fe&lt;/em&gt; And &lt;em&gt;Ni&lt;/em&gt; sunk to the core, while the lighter materials like &lt;em&gt;Al&lt;/em&gt; and &lt;em&gt;Si&lt;/em&gt; stayed at the outer surface of the &amp;quot;ball&amp;quot;.&#xA;Read more about &lt;strong&gt;Planetary differentiation&lt;/strong&gt; if you are interested&lt;/p&gt;&#xA;" OwnerUserId="17188" LastEditorUserId="2470" LastEditDate="2024-01-19T06:12:48.533" LastActivityDate="2024-01-19T06:12:48.533" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17256" PostTypeId="2" ParentId="17104" CreationDate="2019-06-23T16:25:08.883" Score="1" Body="&lt;p&gt;If the sun disappeared the Earth would be flung out of its orbit, and with a bit of luck would collide with another planet to put us all out of our misery. For the Earth to freeze beyond excavatable depths would take hundreds of years; there are mines in S.Africa which are miles deep and are heated to almost unbearable temperatures by heat rising from the Earth's interior, but food stocks would soon run out. To freeze right to the centre of the Earths core would certainly take millions, probably billions of years, because some of the core's heat comes from the decay of radioactive elements. Another almost everlasting source of heat is tides generated by the moon. There are tides in the solid crust as well a in the sea, and the constant flexion of the earth's crust and mantle would generate some heat, but not enough to keep plants and animals alive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fortunately, as I'm sure you understand, this is never going to happen. You could survive for a short while by relocating downwards, but only for a short while, months rather than years, and that's assuming you had food and water down there and you lived in S.Africa and gained access to their deepest mine. Advanced life on Earth depends on the sun. Nothing could grow without it, and therefore when stocks of food ran out they could not be replaced. All traffic, cars, buses trains etc would come to a halt within a few days. To avoid dying a slow and miserable death, the best plan would be to blow your brains out! Rock contracts when it cools, by the way, but water expands when it freezes.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-06-23T16:25:08.883" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17263" PostTypeId="1" AcceptedAnswerId="17269" CreationDate="2019-06-23T23:40:47.240" Score="1" ViewCount="306" Body="&lt;p&gt;Plants do not only come in green but chlorophyll does. The pigment in the plant creates other colored plants other then green.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could a plant grow under an alternative light spectrum like a green sun or a pure green light? Why is the green spectrum of light that of chlorophyll reflected and not absorbed?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6x5AM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6x5AM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2019-06-24T03:46:36.240" LastActivityDate="2019-06-24T17:11:44.360" Title="Why does chlorophyll only come in green?" Tags="|atmosphere|light|plant|" AnswerCount="2" CommentCount="8" ClosedDate="2019-06-24T22:08:26.567" ContentLicense="CC BY-SA 4.0" />
  <row Id="17264" PostTypeId="1" CreationDate="2019-06-24T06:58:52.763" Score="1" ViewCount="30" Body="&lt;p&gt;I am trying to understand how the sediment concentration of a flow affects erosion.  I stumbled across &lt;a href=&quot;https://doi.org/10.1111/j.1365-3091.1968.tb01910.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper by Bagnold (1968)&lt;/a&gt; today that uses a form for the stream power equation that I had not seen before, and haven't yet managed to find anywhere else.  Namely:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;\Omega = Q g S [\rho + C (\sigma - \rho)]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where \Omega is the streampower, Q volumetric flux of the flow, g is gravity, S slope, \rho is the density of the flow, C is the volumetric sediment concentration of the flow, and \sigma is the density of the sediment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This implies that the Stream power increases with increasing sediment concentration.  I do not understand why this would be the case.  I also haven't yet been able to find this relationship anywhere else to give me more context.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My (rather uninformed) intuition was that erosion would decrease as the flow is carrying more sediment - basically because at some point there has to be a limit to how much sediment a flow can carry and it's still a flowing river/stream etc.  But if streampower increases with increased sediment then I would expect that erosion would also increase (since that is driven by streampower), which is quite a feedback loop (although obviously deposition would also increase so it's not a simple one).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone explain what is happening here? Or point me to resources that will help clear up my confusion?  I suspect I'm missing something basic, but not sure.&lt;/p&gt;&#xA;" OwnerUserId="13185" LastActivityDate="2019-06-24T06:58:52.763" Title="Relationship between sediment concentration of flow and erosion - streampower equation" Tags="|rivers|erosion|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17265" PostTypeId="2" ParentId="17263" CreationDate="2019-06-24T08:31:57.437" Score="3" Body="&lt;p&gt;To ask why chlorophyll is green is a bit like asking why haemoglobin is red. That is just the colour of them, in the case of haemoglobin due to the iron content and in the case of chlorophyll probably due to the magnesium atom at the centre of every chlorophyll molecule. As you very likely know, the function of chlorophyll is to carry out photosynthesis, using the magnesium as a catalyst, splitting water into hydrogen and oxygen, then combining the hydrogen with CO2 to create carbohydrates (sugars in the first instance) and more oxygen. The energy source for this process is light, but only light of certain wavelengths will do. Green light isn't up to the job, so it is reflected. There are no green suns, though most stars emit some green light. Whether in other solar systems plants have evolved to use different wavelengths of light than the ones used on Earth is something we can never know, but I think it's unlikely.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-06-24T08:31:57.437" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17269" PostTypeId="2" ParentId="17263" CreationDate="2019-06-24T13:49:16.820" Score="4" Body="&lt;p&gt;chlorophyll is green because that was the part of the spectrum that was left when plants evolved. The bulk of the spectrum was already being harvested by other &lt;a href=&quot;http://adsabs.harvard.edu/abs/2006AAS...209.0605S&quot; rel=&quot;nofollow noreferrer&quot;&gt;photosynthetic life&lt;/a&gt;. there is actually a wide variety of photosynthetic &lt;a href=&quot;https://ucmp.berkeley.edu/glossary/gloss3/pigments.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;pigments&lt;/a&gt; chlorophyll is just one of many. You may want to check out the &lt;a href=&quot;https://en.wikipedia.org/wiki/Purple_Earth_hypothesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;purple earth hypothesis&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Z3DZY.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Z3DZY.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://hyperphysics.phy-astr.gsu.edu/hbase/Biology/ligabs.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sauce&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2019-06-24T17:11:44.360" LastActivityDate="2019-06-24T17:11:44.360" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17273" PostTypeId="2" ParentId="233" CreationDate="2019-06-25T02:04:44.173" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The ocean plays a key role in this vital cycle of water. The ocean&#xA;  holds 97% of the total water on the planet; 78% of global&#xA;  precipitation occurs over the ocean, and it is the source of 86% of&#xA;  global evaporation. Besides affecting the amount of atmospheric water&#xA;  vapor and hence rainfall, evaporation from the sea surface is&#xA;  important in the movement of heat in the climate system. Water&#xA;  evaporates from the surface of the ocean, mostly in warm, cloud-free&#xA;  subtropical seas. This cools the surface of the ocean, and the large&#xA;  amount of heat absorbed the ocean partially buffers the greenhouse&#xA;  effect from increasing carbon dioxide and other gases. Water vapor&#xA;  carried by the atmosphere condenses as clouds and falls as rain,&#xA;  mostly in the ITCZ, far from where it evaporated, Condensing water&#xA;  vapor releases latent heat and this drives much of the the atmospheric&#xA;  circulation in the tropics. This latent heat release is an important&#xA;  part of the Earth’s heat balance, and it couples the planet’s energy&#xA;  and water cycles.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://docsbay.net/water-cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;Water Cycle&lt;/a&gt; from Global Environmental Change&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nZpVn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nZpVn.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17045" LastActivityDate="2019-06-25T02:04:44.173" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17277" PostTypeId="1" AcceptedAnswerId="17305" CreationDate="2019-06-25T03:08:21.927" Score="10" ViewCount="3679" Body="&lt;p&gt;While google earth-researching the sea floor near Malpelo and Cocos Islands (Colombian and Costa Rican Pacific Ocean), I came along these strangely geometrical structures in the sea floor, located around 6°N, 85°55'W. I'm fascinated with the look and the geometric perfection they have, and have waited to ask this question for about 3 years, until today that I realized there's a Stack Exchange site dedicated to earth sciences (I'm not an earth scientist, just a maps enthusiast).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dsvY8.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dsvY8.jpg&quot; alt=&quot;Structures near Cocos Island&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At first I thought they could be due to the path the satellite was traveling at the moment the image was captured, but then I realized there are depth differences in excess of 300m. I find the paralelism of the lines that form the &quot;beams&quot; surprisingly perfect, and the width of the &quot;elements&quot; very consistent (about 7 to 8km, according to google earth's ruler). Near 6°22'N 85°45'W there's a circular &quot;dent&quot; of about 4 &lt;span class=&quot;math-container&quot;&gt;$km^2$&lt;/span&gt; that is very &lt;em&gt;perfect&lt;/em&gt; regarding ovality.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found something similar about 670km NE from there, around 11°10'N 82°41'W (160km SW from San Andres Islands, in the Colombian Caribbean). While the structure here is less complex (there's only one &quot;beam&quot; and a concentric circular structure), the width of the &quot;beam&quot; (6km) seems similar to the one near Cocos (the depth differences range between 300 and 500m from the structures to the normal sea floor).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nY9Yg.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nY9Yg.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are these things? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are they glitches in the images from the satellite, that coincidentially look like beams? If so, why are depth differences so significative?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are they rocks or some other kind of geological formations? How did they get that shape, and where else cand I find more similar?&lt;/p&gt;&#xA;" OwnerUserId="17216" LastEditorUserId="6298" LastEditorDisplayName="user12525" LastEditDate="2022-02-06T17:23:18.437" LastActivityDate="2022-02-06T17:23:18.437" Title="What are these underwater structures near 6°N 85°55'W" Tags="|satellites|sea-floor|ground-truth|satellite-oddities|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17279" PostTypeId="2" ParentId="17214" CreationDate="2019-06-25T03:32:10.197" Score="1" Body="&lt;p&gt;Looks like the Xenodiscaceae (an ammonite family, as the top comment already mentioned.) Based on the region where you found it, my research suggests it is very old, from a time known as the Permian (250 million years to 300 million years ago.)&lt;/p&gt;&#xA;" OwnerUserId="17215" LastActivityDate="2019-06-25T03:32:10.197" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17280" PostTypeId="2" ParentId="17226" CreationDate="2019-06-25T03:42:36.963" Score="0" Body="&lt;p&gt;I submit the argument that it wouldn't have much an effect on the scale you're inquiring. A 5km wide impactor (like the Manicouagan was calculated to be) in the massive ocean, wouldn't do much damage. I do think you're right in suggesting there would be some effect, but I don't think it would be on a scale to change the climate. I also think that such an impact would completely obliterate the impactor. The velocities at which impact occurs would have similar consequences on land vs water, in that it would be akin to the impacting body slamming into land. You know how water can feel hard when you slap it with just your hand? Imagine it being an asteroid moving at several km/s. It would be like slamming into a solid surface, and thus I submit the asteroid would vaporize upon impact.&lt;/p&gt;&#xA;" OwnerUserId="17215" LastActivityDate="2019-06-25T03:42:36.963" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17287" PostTypeId="1" CreationDate="2019-06-25T05:41:36.033" Score="1" ViewCount="506" Body="&lt;p&gt;On reading about tide formation and the role of moon's gravitational force, I came across the term amphidromic point. Could someone please elaborate this concept?&lt;/p&gt;&#xA;" OwnerUserId="17178" LastActivityDate="2019-06-25T20:09:40.323" Title="What is the significance of amphidromic points related to tides?" Tags="|oceanography|geography|tides|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17289" PostTypeId="2" ParentId="16824" CreationDate="2019-06-25T07:19:06.577" Score="2" Body="&lt;p&gt;These are weakly formed gravity clouds or density clouds. Clouds are formed from condensation, which is just tiny water (and other gases) droplets and vapor. As such, these tiny droplets and vapors will flow like ripples on the surface of water in a slow breeze. What you're seeing here is light-action wave ripples in the atmosphere and the resulting effect on the tiny droplets, is a wave-like or ripple-like pattern. &lt;/p&gt;&#xA;" OwnerUserId="17215" LastActivityDate="2019-06-25T07:19:06.577" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17293" PostTypeId="2" ParentId="13004" CreationDate="2019-06-25T08:10:01.997" Score="2" Body="&lt;p&gt;The short answer is &quot;yes&quot; and the links are provided below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fireball reports: &lt;a href=&quot;https://www.amsmeteors.org/fireballs/fireball-report/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.amsmeteors.org/fireballs/fireball-report/&lt;/a&gt;&#xA;Classified meteorites: &lt;a href=&quot;https://www.lpi.usra.edu/meteor/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.lpi.usra.edu/meteor/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17215" LastActivityDate="2019-06-25T08:10:01.997" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17294" PostTypeId="2" ParentId="127" CreationDate="2019-06-25T08:22:04.653" Score="1" Body="&lt;p&gt;When meteorites are found, they are cold, much like it is in deep space. The meteor body may be warm to the touch (has been reported, whether or not it is true is another thing) but it is important to know that it is the air around the meteor which is emulating visible light, not the rock itself.&#xA;Light flight: what we see (the fireball), which occurs from approx 80km altitude and continues to approx 20km altitude.&#xA;Dark flight: From 20 km altitude to surface. The rock is now falling at terminal velocity and would not retain any heat from the heated luminescent air during it's light flight. &#xA;The end result: meteorites are cold to the touch upon impact.&#xA;The proof: meteorites found on snowy surfaces or grassy surfaces. The snow isn't melted and grass isn't burnt. Sure is fun reading some eye witness accounts stories though lol. They are most certainly fabricated to cause shock value. The science doesn't lie.&lt;/p&gt;&#xA;" OwnerUserId="17215" LastActivityDate="2019-06-25T08:22:04.653" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17296" PostTypeId="2" ParentId="16988" CreationDate="2019-06-25T08:36:12.407" Score="0" Body="&lt;p&gt;It is called preferential weathering, but there is another element at play. Before the rock eroded into circular features, there were softer materials present. Those softer materials weathered away first leaving the more resistant host rock (or matrix) behind. The matrix is harder than the softer &quot;clastic&quot; material. When pebbles get washed into the cliff face, the pebbles will slowly break down the softer material first and eventually the wave-action of pebbles will continue to grind as they spin and get rolled around in these little crevasses, which can grow in size as is seen in many Tafoni rock faces.&lt;/p&gt;&#xA;" OwnerUserId="17215" LastActivityDate="2019-06-25T08:36:12.407" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17297" PostTypeId="1" AcceptedAnswerId="17304" CreationDate="2019-06-25T08:52:42.460" Score="3" ViewCount="178" Body="&lt;p&gt;I have been reading some documents about meteorological data and many of them mention the &lt;strong&gt;second moment of wind velocity&lt;/strong&gt;.&#xA;I guess it has to do with the way the wind is changing but in such case I would call it a gradient... Therefore, what is it's correct physical representation? &lt;/p&gt;&#xA;" OwnerUserId="7458" LastActivityDate="2019-06-26T03:09:53.207" Title="What is the physical meaning of second moment of wind velocity?" Tags="|meteorology|wind|weather-forecasting|statistics|turbulence|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="17300" PostTypeId="2" ParentId="16988" CreationDate="2019-06-25T12:28:17.593" Score="3" Body="&lt;p&gt;I had a good geomorphology teacher. He was so good that I bought his book, published on Prentince Hall at 2008. He is an aged an experimented geomorphologist, so I totaly trust there is not an agreement about the physical origin of tafonies (or at least there wasn't an agreement at 2008 when his book was published).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Its origin [tafonis] is controversial (Twidale and Vidal Romaní, 2005). Some authors differentiate between wall tafonis and basal tafonis, linked to the processes of basal undermining (Smith, 1978, Bradley et al., 1978). It is agreed that the dominant processes are those related to the movement of water with salts close to the surface, which correspond to haloclastism and wetting and drying. Thermoclastism, cryoclasty, dissolution of carbonated cements and wind erosion are also mentioned (Evans, 1969-70, Mustoe, 1983, Young, 1987, Robinson and Williams, 1992). In addition to these subaerial processes, some taphonis can be generated by weathering under the soil surface and subsequent exhumation by erosion (Dragovich, 1969).&quot;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;strong&gt;Source&lt;/strong&gt;: &lt;a href=&quot;https://www.casadellibro.com/libro-geomorfologia/9788483223895/1197545&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geomorfología, Prentince Hall (2008)&lt;/a&gt;, page 152. &#xA;  Translated from spanish by Google.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;-Gutiérrez Elorza, M. (2008) &quot;Geomorfología&quot;. Ed Prentince Hall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-Twidale, C. R.; Bourne, J.A., y Vidal Romaní, J.R. (2005): &quot;Beach etching and shore platforms&quot; &lt;em&gt;Geomorphology&lt;/em&gt; 67, 47-61.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-Smith (1978) &quot;The origin and geomorphic implications of cliff foot recesses and tafoni on limestone hamadas in the northwest Sahara&quot; &lt;em&gt;Zeitscrift für Geomorphologie&lt;/em&gt;, 22, 21-43.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-Bradley, W.C.; hutton, J.T., y Twidale, C.R.(1978). &quot;Role of salts in development of granitic tafoni, South Australia&quot;. &lt;em&gt;Journal of Geology&lt;/em&gt; 86, 647-654.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-Evans, I.S. (1969-70) &quot;Salt crystallization and rock weathering: a review&quot; &lt;em&gt;Revue de Géomorphologié Dynamique&lt;/em&gt;, 19,153-177.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-Mustoe, G.E.(1983)&quot;Cavernous weathering in the Capitol Reef Desert, Utah&quot; &lt;em&gt;Earth Surface Processes and Landforms&lt;/em&gt; 8, 517-526&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-Young, R.M. (1987) &quot;Salt as an agent in the development of cavernous weathering&quot; &lt;em&gt;Geology&lt;/em&gt; 15, 962-966.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-Robinson, D.A. Williams, R.B.G.(1992) &quot;Sandstone weathering in the High Atlas, morocco&quot; &lt;em&gt;Zeitscrift für Geomorphologie&lt;/em&gt; 4,413-429.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-Dragovich, D. (1969): &quot;The origin of cavernous surfaces (tafoni) in granitic rocks of Southern Australia&quot;. &lt;em&gt;Zeitscrift für Geomorphologie&lt;/em&gt; 13, 163-181.&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-06-25T17:51:55.467" LastActivityDate="2019-06-25T17:51:55.467" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17302" PostTypeId="2" ParentId="17287" CreationDate="2019-06-25T20:09:40.323" Score="1" Body="&lt;p&gt;&lt;em&gt;This will be a bare-bones answer, because I don't have time to do more. If somebody wants to do a more complete answer, with a figure or two, feel free; otherwise I'll try to come back and expand this in a day or two&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Good question! If one is familiar with the simple explanations of tides (bulges of water following the moon around the earth), this doesn't make sense. &#xA;However, that way of thinking only gives us &lt;em&gt;equilibrium tides&lt;/em&gt;, which are what we would have if Earth was an ocean planet. In reality, we have continents, and they get in the way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most tidal movement actually consists of water &quot;sloshing&quot; around ocean basins - e.g. across the Atlantic between North America and Europe. But because the planet is spinning, Coriolis force applies and tends to impart rotation to straight-line movements. This results in the tide tending to form two-dimensional waves that go around ocean basins in a roughly circular pattern. You can get a similar wave going in a hot-tub, with a bit of effort! At the outside of the basin, where the wave meets the land, the amplitude tends to be the greatest - but in the middle, it's close to zero.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-06-25T20:09:40.323" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17303" PostTypeId="2" ParentId="12440" CreationDate="2019-06-26T03:02:05.197" Score="0" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The oldest geologic units in the study area are the Precambrian&#xA;  crystalline (metamorphic and igneous) rocks, which form a&#xA;  basement under the Paleozoic, Mesozoic, and Cenozoic rocks and&#xA;  sediments. The Precambrian rocks range in age from 1.7 to about&#xA;  2.5 billion years, and were eroded to a gentle undulating plain at the beginning of the Paleozoic era (Gries, 1996). The Precambrian rocks&#xA;  are highly variable, but are composed mostly of igneous rocks or&#xA;  metasedimentary rocks, such as schists and graywackes. The Paleozoic&#xA;  and Mesozoic rocks were deposited as nearly horizontal beds.&#xA;  Subsequent uplift during the Laramide orogeny and related erosion&#xA;  exposed the Precambrian rocks in the crystalline core of the Black&#xA;  Hills, with the Paleozoic and Mesozoic sedimentary rocks exposed in&#xA;  roughly concentric rings around the core. Deformation during the&#xA;  Laramide orogeny contributed to the numerous fractures, folds, and&#xA;  other features present throughout the Black Hills. Tertiary intrusive&#xA;  activity also contributed to rock fracturing in the  northern Black&#xA;  Hills where numerous intrusions exist.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://docsbay.net/geologic-setting&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geologic Setting&lt;/a&gt; by USGS Publications Warehouse&lt;/p&gt;&#xA;" OwnerUserId="17225" LastActivityDate="2019-06-26T03:02:05.197" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17304" PostTypeId="2" ParentId="17297" CreationDate="2019-06-26T03:09:53.207" Score="2" Body="&lt;p&gt;The (statistical) variation is not the same as the gradient. The gradient is a measure how things change from here to a nearby point, or from now to a point in the near future. The variation, on the other hand, just says how often wind speeds of different magnitude happen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example: If the wind were to blow at exactly 30 km/h all the time, then the average wind velocity is going to be 30 km/h and the variation is zero. Conversely, if the average is 30 km/h and the variation is large, then the wind will blow at different speeds, typically quite different than 30 km/h, but so that the &lt;em&gt;average&lt;/em&gt; is 30 km/h. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What's the importance in the context you're considering? If the variation were small, it would be fairly easy to design wind generators because they would only have to accommodate exactly one wind speed, which happens to be blowing all the time. On the other hand, if the variation is large, then you have to design wind generators so that they can produce electricity when there is little wind, when there is the average wind speed, and also when there is a storm. It's a bit like designing aircraft for (slow) take-off and (fast) cruise speeds -- it's complicated, as you can see with all of the flaps and levers moving on the wings of planes between start and cruise phase.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2019-06-26T03:09:53.207" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17305" PostTypeId="2" ParentId="17277" CreationDate="2019-06-26T03:19:36.590" Score="18" Body="&lt;p&gt;As the other answer suggests, these are sonar surveys of the ocean depths. But the answer is a bit more complicated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The vast majority of the ocean floor has never been mapped. We really only know about the water depth because the water above the sea floor is lighter than if it were rocks. So a deep ocean produces less gravity than a shallow one. And, miraculously, you can fly satellites over the oceans that pick up on how hard Earth pulls on the satellite at any given point and convert that data into an ocean depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is what Google Maps and other mapping services show by default. The problem is that this information is not very accurate: That's because not just the point immediately under the satellite pulls on the satellite, but also points elsewhere. So a very steep undersea mountain will not be distinguishable from a broader but less high one. This is why in &lt;em&gt;general&lt;/em&gt; these images of ocean depths are not shown in high resolution -- we just don't know the depth of the ocean on length scales of a few kilometers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But then along comes the occasional ocean survey. (Think: Research ships, the ships that lay undersea cables, the ships that search for ship wrecks or the occasional plane that fell from the sky.) They tow a sonar array behind a ship, or send a side-scan sonar equipped submersible, to actually map the ocean floor on length scales of a few dozen meters. For map services, this presents a conundrum: They'd like to show the more accurate sonar data where it is available, but they need to overlay it on the low resolution maps that comes from satellites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is exactly what you see here: The background is the low-resolution satellite map. Overlaid is the high resolution sonar data. At the edges of the sonar maps, these two maps won't match, and so you will see the sharp edges. You can see the different resolutions if you zoom in and out of the view you showed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Given the long straight tracks of these sonar maps, one can guess that in your view, these were created by surveys for laying undersea cables, for example to the  Galapagos Islands.)&lt;/p&gt;&#xA;" OwnerUserId="5259" LastEditorUserId="5259" LastEditDate="2019-07-03T16:00:17.667" LastActivityDate="2019-07-03T16:00:17.667" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17307" PostTypeId="2" ParentId="16553" CreationDate="2019-06-26T07:50:54.653" Score="1" Body="&lt;p&gt;I do not think there is one name for the area. Rather it is a region with multiple plates, namely the Timor Plate, the eastern portion of the Banda Sea Plate, the Maoke Plate and the Woodlark Plate, all of which lie on the Arafura shelf which lies upon the Australian Plate. The Timor trough, Tanimbar Trough and Aru Trough would cover the western portion of the area you are questioning. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/d8cuG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/d8cuG.png&quot; alt=&quot;Timor Trough&quot;&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/To2Ls.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/To2Ls.jpg&quot; alt=&quot;Tanimbar Trough&quot;&gt;&lt;/a&gt;&#xA;The Papuan Thrust and Fold Belt (PTFB) and the Aure Trough make up the northern and eastern portion of the area in question. Hope this helps. &lt;a href=&quot;https://i.stack.imgur.com/1XtJB.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1XtJB.gif&quot; alt=&quot;PTFB_Aure&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17215" LastActivityDate="2019-06-26T07:50:54.653" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17309" PostTypeId="1" CreationDate="2019-06-26T14:32:10.830" Score="4" ViewCount="239" Body="&lt;p&gt;The climate impact of air travel is often divided into CO&lt;sub&gt;2&lt;/sub&gt; emissions and &quot;high altitude effects&quot; like that of water vapour and cloud formation. The effect of the emitted CO&lt;sub&gt;2&lt;/sub&gt; is cummulative, as CO&lt;sub&gt;2&lt;/sub&gt; has a high retention time in the atmosphere. On the other hand, as I have understood it, the high altitude effects are more short lived. Their impact on temperature are determed by current levels of air travel, and not past.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can the size of these two effects be compared to each other or to other sectors such as travel by car? Is there any videly accepted method for this? It seems a bit like apples and oranges to me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know about GWP, that uses a somewhat arbitrary timeframe of 100 years. Is and can that be used here? I have also heard about RFI, but I am unsure how that works or is applied to this.&lt;/p&gt;&#xA;" OwnerUserId="17232" LastActivityDate="2019-07-10T19:12:44.750" Title="How are CO2 emission effects and high altitude effects of air travel compared to each other?" Tags="|climate-change|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17310" PostTypeId="2" ParentId="17250" CreationDate="2019-06-26T14:35:43.117" Score="3" Body="&lt;h1&gt;&lt;a href=&quot;http://www.snowballearth.org/people.html#hoffman&quot; rel=&quot;nofollow noreferrer&quot;&gt;Paul Hoffman&lt;/a&gt;'s argument for Snowball Earth&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;So, first off, I'm just a guy with access to JSTOR and an interest in geology, so perhaps I'm not really qualified to assess &quot;how good&quot; the evidence is. But, I can read through the papers and summarize some stuff for you, which perhaps is sufficient to answer the question. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, as suggested in the title, serious consideration of the Snowball Earth theory started with a Paul Hoffman paper in 1998, free copy &lt;a href=&quot;http://www.snowballearth.org/pdf/Hoffman_Science1998.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;linked here&lt;/a&gt;. The evidence in the initial paper is thus:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Inorganic &lt;span class=&quot;math-container&quot;&gt;$\delta^{13}$&lt;/span&gt;C showed decreases during glacial periods between 750 and 550 Ma that were 'enormous in comparison' with variation seen at other times in the Earth history. This references previous stratigraphic work by Alan Kaufman, a co-author on the paper we are discussing.&lt;/li&gt;&#xA;&lt;li&gt;Based on a theory by &lt;a href=&quot;https://en.wikipedia.org/wiki/Joseph_Kirschvink&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kirschvink&lt;/a&gt; (the geologist who proposed the Snowball Earth theory), an ocean completely sealed by sea ice would quickly become anoxic, leading to chemical reactions that would cause the observed changes in carbon deposition.&lt;/li&gt;&#xA;&lt;li&gt;New stratigraphic work in the Otavi Group formation in Namibia confirms the drop in inorganic carbon, as well as providing evidence of glaciation on land at a latitude of ~12 S (latitude determined by paleomagnetic data; age determined by radiometry). &lt;/li&gt;&#xA;&lt;li&gt;The geological evidence suggests that the proportion of organic carbon in total carbon burial drops to &quot;virtually zero&quot; immediately after the glaciation begins. &lt;/li&gt;&#xA;&lt;li&gt;The paper then presents evidence that a large volcanic event with C)&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; levels &gt; 300 times the present could &quot;undo&quot; the Snowball Earth event. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In the conclusion, the authors say that a Snowball Earth explains the evidence from carbon isotope excursions, but no alternative hypothesis does. This is discussed more in detail in &lt;a href=&quot;https://www.geosociety.org/gsatoday/archive/8/5/pdf/i1052-5173-8-5-1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Hoffman, et al., 1998a&lt;/em&gt;&lt;/a&gt; (an article by the same authors, the same year) and &lt;em&gt;&lt;a href=&quot;https://onlinelibrary.wiley.com/doi/full/10.1046/j.1365-3121.2002.00408.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hoffman and Schrag, 2002&lt;/a&gt;&lt;/em&gt;. Among hypotheses rejected include a period of ocean stagnation and overturn; the Earth having a larger axial title until the end of the Proterozoic, &lt;a href=&quot;https://en.wikipedia.org/wiki/True_polar_wander&quot; rel=&quot;nofollow noreferrer&quot;&gt;true polar wander&lt;/a&gt;, a major bolide impact, deep ocean anoxia and others. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The point I want to make here is that the questions that you ask in the OP don't fit into the original explanation for why there might have been a Snowball Earth episode. It is true, that without accurate fossil dating, radiometric methods can't prove that near-equatorial glaciers occured in multiple places &lt;em&gt;at the same time&lt;/em&gt;. But, that isn't really a required proof. Evidence for Snowball Earth is &quot;good&quot; as long as it is the &lt;em&gt;most likely&lt;/em&gt; explanation for the observed paleomagnetic, stratigraphic, and carbon isotope data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That last is the part that I am perhaps not qualified to speak on; you'd have to do a full literature review on both Snowball Earth and alternate theories to determine which has the best evidence supporting it. But, clearly there are many geologists who thing that Snowball Earth is the &quot;best&quot; hypothesis. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Answers to specific questions&lt;/h1&gt;&#xA;&#xA;&lt;h3&gt;Although at the beginning of this period, there were, so far as we know, no advanced invertebrates able to leave easily identifiable fossils, there were by the end of it, so how were they able to thrive and evolve under the ice?&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;http://web.gps.caltech.edu/~jkirschvink/pdfs/snowball.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kirshvink, et al., 2000&lt;/a&gt;, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Finally, we speculate that the predicted severity of climate and&#xA;  geochemical change during the snowball event and its aftermath may&#xA;  have forced enormous biological adaptation and left recognizable&#xA;  signatures in the phylogenies of extant organisms and their genes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The extreme geochemical conditions include significant changes oxygen and iron availability. Thought the above article specifically addresses an earlier Snowball Earth episode, the suggestion is that the few organisms that did survive the glaciation had novel geochemical adaptations that allowed them to explode into the much more friendly world environment that existed after glaciation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Indeed, the Ediacara fauna appeared after the glaciations had passed; from &lt;a href=&quot;https://pubs.geoscienceworld.org/gsa/geology/article-abstract/18/12/1199/198524/ediacaran-remains-from-intertillite-beds-in?redirectedFrom=fulltext&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Hofmann, et al., 1990&lt;/em&gt;&lt;/a&gt; (not the same Hoffman/Hofmann; also couldn't find a free full copy):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Ediacara fauna generally regarded as containing the oldest&#xA;  metazoan fossils, has been described from about 25 localities around&#xA;  the world; all occurances to date place it above the highest&#xA;  Proterozoic tillites of the Varanger glacial epoch.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The Varanger glacial epoch is what is now theorized to be the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cryogenian&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cryogenian&lt;/a&gt; period, divided into two glaciations, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Sturtian_glaciation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sturtian&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Marinoan_glaciation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Marinoan&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, overall, the explosion of evolution and diversity happened after the glaciation passed, and it happened because radial new biochemical processes had to be evolved to survive in the radically divergent marine chemistry of the frozen ocean. &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;There must also have been early marine plants under the ice (there were none on land), so how did they survive?&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Eukaryotic algae (like &lt;a href=&quot;https://en.wikipedia.org/wiki/Red_algae&quot; rel=&quot;nofollow noreferrer&quot;&gt;red&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Brown_algae&quot; rel=&quot;nofollow noreferrer&quot;&gt;brown&lt;/a&gt; algae) existed before the Cryogenian, and survived until after. There are many mechanisms for them to have survived. Firstly, algae do live on the snow on the terrestrial surface of Antarctica; such &quot;&lt;a href=&quot;http://www.antarctica.gov.au/about-antarctica/wildlife/plants/snow-algae&quot; rel=&quot;nofollow noreferrer&quot;&gt;snow algae&lt;/a&gt;&quot; could have survived on Snowball Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly, there is no consensus that the surface of the Ocean was uniformly thick. Some modeling, for example from &lt;a href=&quot;https://pdfs.semanticscholar.org/4cac/399c01bbfa07f86a1790f9aaf3dc5f7c2cdc.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Pollard and Kasting, 2005&lt;/em&gt;&lt;/a&gt; indicates that the sea ice was on the order of meters thick in the equatorial regions. In that case, algae could have easily survived on the underside of ice sheets, as it does in the modern arctic and antarctic. A &lt;a href=&quot;https://oceanexplorer.noaa.gov/explorations/02arctic/background/sea_ice/sea_ice.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;thin, cracking, and periodically melting&lt;/a&gt; (under tropical solar radiation) state would be consistent with conditions in the polar regions today, and is quite capable of supporting life. &lt;/p&gt;&#xA;&#xA;&lt;h3&gt;Couldn't there be other explanations for these apparent glacier tracks, apart from Snowball Earth? For example, Australia may have been closer to the S.Pole then, and some of the locations where evidence of glaciers was found might have been much higher above sea level than they are today.&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;I haven't done a deep dive, but the latitude of various points of the Earth's surface can be estimated by paleomagnetic data. Note that the many of the alternate explanations (such as increased axial tilt and true polar wander) also include mechanisms for explaining why the magnetic record is wrong (i.e. the magnetic poles were not where we though they were). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this is something of an Occam's Razor situation. In order to explain tropical glaciers without Snowball Earth, you have to explain how the Earth was physically rotating on a different axis. While possible, it takes a lot of energy to make the Earth move from one axis of rotation to another. Snowball Earth is a simpler explanation from the energy physics point of view. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As mentioned earlier, there are two links to papers where Hoffman and company dismiss various alternate explanations.&lt;/p&gt;&#xA;" OwnerUserId="6703" LastActivityDate="2019-06-26T14:35:43.117" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17311" PostTypeId="1" CreationDate="2019-06-26T21:36:11.560" Score="11" ViewCount="268" Body="&lt;p&gt;The consensus view is that that the Earths core is composed mainly of iron alloyed with about 10 percent nickel and traces of other heavy metals, but I have seen at least one account which says it is partly iron sulphide. Has the iron sulphide theory been discredited, or is it a view still held by some geologists? There is a recent theory that about 5 percent of the core is composed of silicon. How valid is this, and will we ever be able to establish more precisely what the core is made of?&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorDisplayName="user20559" LastEditDate="2021-06-01T18:43:45.933" LastActivityDate="2021-06-01T18:43:45.933" Title="How Can We Establish Precisely What Earth's Core is Made Of?" Tags="|geology|geophysics|core|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17312" PostTypeId="1" CreationDate="2019-06-27T00:48:56.183" Score="-2" ViewCount="111" Body="&lt;p&gt;Honestly I think nobody's invented a good water desalination device because nobody knows the scientific definition of clean drinking water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So scientifically, what is the definition of clean fresh water?&lt;/p&gt;&#xA;" OwnerUserId="17238" LastEditorUserId="17238" LastEditDate="2019-06-28T18:48:49.313" LastActivityDate="2019-06-28T18:48:49.313" Title="How does one scientifically define drinkable water?" Tags="|water|" AnswerCount="1" CommentCount="10" ClosedDate="2019-06-28T23:46:13.420" ContentLicense="CC BY-SA 4.0" />
  <row Id="17313" PostTypeId="2" ParentId="16787" CreationDate="2019-06-27T00:50:01.990" Score="8" Body="&lt;p&gt;Wolfram Alpha reports values between 9.78 and 9.88 m/s&lt;sup&gt;2&lt;/sup&gt; depending on the location, which is odd because it should stay within the range 9.76 - 9.83 all over the world. It also seems to be using the ocean floor as a reference elevation if the point falls in water.&lt;/p&gt;&#xA;&lt;p&gt;Using &lt;a href=&quot;http://webapp.geod.nrcan.gc.ca/geod/tools-outils/gpsh.php?locale=en&amp;amp;&quot; rel=&quot;nofollow noreferrer&quot;&gt;Natural Resources Canada's tool&lt;/a&gt;, it reports a gravity of 981933.3 mGal (9.819333 m/s&lt;sup&gt;2&lt;/sup&gt;) for Hudson Bay at 60.9N, 94.1W at sea level, which seems more likely for that location.&lt;/p&gt;&#xA;&lt;p&gt;Keep in mind that while the area near Hudson Bay has a negative gravity anomaly, this does not imply that it should have weaker gravity than Chicago (9.8026 m/s&lt;sup&gt;2&lt;/sup&gt;), which is much closer to the equator. It means that Hudson Bay's gravity is lower than what it should be &lt;em&gt;at that latitude&lt;/em&gt;.  Gravity is even weaker near the equator (around 9.78) because as you get closer to the equator, the centrifugal force is stronger and slightly counteracts the force of gravity, also the mass of the Earth is slightly further away from you, thus has less gravitational pull on you. These 2 effects alone create gravity variations up to 0.5% (around 0.05 m/s&lt;sup&gt;2&lt;/sup&gt;)&lt;/p&gt;&#xA;&lt;p&gt;Gravity anomalies are relative to a theoretical normal gravity based on an idealized ellipsoidal rotating Earth, and these anomalies are small compared to the variation caused by cetrifugal forces and the oblateness of the Earth. Anomalies range between -50 and +50 mGal (+-0.0005 m/s&lt;sup&gt;2&lt;/sup&gt;). Normal gravity at the Equator for sea level is about 9.78 m/s&lt;sup&gt;2&lt;/sup&gt;, and near the poles, around 9.83 m/s^2. Altitude also has a significant effect, at 5000 meters, gravity is about 0.01 m/s&lt;sup&gt;2&lt;/sup&gt; weaker than at sea level.&lt;/p&gt;&#xA;" OwnerUserId="17236" LastEditorUserId="2470" LastEditDate="2023-09-27T06:09:36.607" LastActivityDate="2023-09-27T06:09:36.607" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17314" PostTypeId="1" CreationDate="2019-06-27T08:29:03.280" Score="2" ViewCount="299" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/s0RAb.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/s0RAb.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;strong&gt;Source&lt;/strong&gt; : &lt;a href=&quot;https://www.weather.gov/media/zhu/ZHU_Training_Page/clouds/stability_clouds/stability_clouds.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;weather.gov&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;This is mentioned in the book I have been reading regarding stability in atmosphere. &#xA;But I am not able to pin point exact reason behind this.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;As the layer subsides, it becomes compressed by the weight of the&#xA;  atmosphere and shrinks vertically. The upper part of the layer sinks&#xA;  farther, and, hence, warms more than the bottom part.&quot; (Ahrens et al.,2019)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;-&lt;strong&gt;Ahrens, C.D., Henson, R. (2019)&lt;/strong&gt;. &quot;Meteorology Today: An Introduction to Weather, Climate, and the Environment&quot;. 12th Edition. Chapter 6 ( Stability and Cloud Development), &lt;em&gt;CENGAGE Learning Custom Publishing&lt;/em&gt;, page 146-147&lt;/p&gt;&#xA;" OwnerUserId="2756" LastEditorUserId="2756" LastEditDate="2019-06-27T12:44:32.770" LastActivityDate="2019-08-09T07:59:39.070" Title="Why during subsidence inversion, upper layer warms more than lower layer?" Tags="|meteorology|atmosphere|inversion|" AnswerCount="1" CommentCount="13" ContentLicense="CC BY-SA 4.0" />
  <row Id="17315" PostTypeId="2" ParentId="17312" CreationDate="2019-06-27T09:24:40.413" Score="2" Body="&lt;p&gt;I think everyone would agree that distilled water is clean fresh water, but it wouldn't be practical to supply a large population with a water supply made up entirely of distilled water. Good water desalination devices using semi-permeable membranes have been invented and are used in some drought stricken countries. They can filter out things as small as sodium and chlorine ions, so produce very high quality water, but it tends to be expensive. When you are talking about a water supply for millions of people, these expensive purification methods are not practical for everyday purposes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The basis of a mass supply of clean, fresh water suitable for drinking is filtration, so water from reservoirs is run through filtration beds of sand to remove particulate matter and most micro-organisms. It then has to be sterilised, which is done with chlorine. The result is a product which although containing a number of impurities in trace amounts (chlorine, calcium, iron etc) which are not harmful, fulfils the scientific definition of clean, fresh water suitable for drinking. Water from deep boreholes is also suitable despite trace amounts of mineral impurities, and is free of harmful micro-organisms so needs no sterilisation. Shallower wells and boreholes may be contaminated by pathogenic microbes, so the water sometimes needs sterilisation. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-06-27T09:24:40.413" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17316" PostTypeId="1" CreationDate="2019-06-27T12:50:02.337" Score="1" ViewCount="547" Body="&lt;p&gt;Trying to understand this question, posted to me by a lecturer at University:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;The Medieval Climatic Anomaly was distinctive in terms of the&#xA;  prevailing climates and forcing mechanisms operating at the regional scale.&quot;&lt;br /&gt;&#xA;  Critically evaluate this comment using case-studies to support your answer &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Is this statement saying that the MCA was caused only by the prevailing climate and mechanisms operating on a regional scale?&lt;br /&gt;&#xA;If so what is an example of a regional scale forcing mechanism? &lt;/p&gt;&#xA;" OwnerUserId="17241" LastEditorUserId="595" LastEditDate="2019-06-27T14:23:08.560" LastActivityDate="2023-03-31T13:01:55.280" Title="The Medieval Climatic Anomaly" Tags="|climate-change|climate|climate-models|climatology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17317" PostTypeId="1" CreationDate="2019-06-27T23:22:58.387" Score="-4" ViewCount="568" Body="&lt;p&gt;Ask any climate scientist the question:  &quot;Why are deserts so hot in the day time and so cold at night&quot; and generally you will get the same answer, it’s all about the lack of moisture and latent heat and the greenhouse gas effect.  Consider however for example, a simple household convection heater that uses the principles of:  a radiator, conduction and convection to warm a house.  The radiator fins greatly increase the surface area of the heat source to significantly increase the conduction of heat to the air and the basic concept of convection circulated the warm air upward.  Very efficient, and control is simply to turn the element on and off with a thermostat.  A less used method of control however, but still effective, is simply  to block the fins so conduction and convection is reduced.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Enter Mother Nature, with sand deserts covering vast surfaces of the earth.  Any geologist will tell you that Aeolian sand deposits can have porosities upwards of over 45%, permeability is unlimited and finally the surface area of the sand grains (on and below the surface) for heat conduction is hundreds of times greater than just a flat non porous surface.  The Sahara Desert covers 3.5 million square miles of  Aeolian sand deposits.  The sun supplies the heat to the sand both at the surface and below (surface conduction grain to grain), the sand grains are the radiator fins that conduct heat to the air and finally convection looks after the rest.  Shut off the sun every night and the sand cools very quickly because of the increased conduction and convection soon replaces the hot air with cold.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of Europe right now is experiencing a massive heat wave coming from the Sahara Desert to the south and of course blames global warming.  The question is &quot;Are Sand Deserts The Greatest Natural Convection Heaters On Earth&quot; and can we control them?  We cannot control the sun, but can we not close some of the fins on these &quot;desert convection heaters&quot;, perhaps by sealing some of the surfaces of the desert sands with tarps or liquid sealers?  Anything that stops the convection will reduce the heat output.  Has Mother Nature in the past, been playing with the Earth's thermostat simply by reducing and increasing the size of our great deserts?&lt;/p&gt;&#xA;" OwnerUserId="17129" LastEditorUserId="106" LastEditDate="2019-06-28T08:44:44.140" LastActivityDate="2019-12-07T12:10:17.313" Title="Are sand deserts the greatest natural convection heaters on Earth?" Tags="|geology|climate-change|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17319" PostTypeId="2" ParentId="6708" CreationDate="2019-06-28T03:47:38.830" Score="0" Body="&lt;p&gt;Of the three categories of rocks, sedimentary, igneous and metamorphic, sedimentary is the closest type that coal could fit into. Coal was not derived from molten material, so is not igneous by definition. It was not transformed under temperature and pressure from a pre-existing rock into a metamorphic rock. Coal was lithified by compressive forces from loose material at relatively low temperature. This is most similar to how sedimentary rock is formed, which is generally the compaction and cementation of inorganic material. The primary difference between coal and other sedimentary rocks is that by definition &quot;rock&quot; is an aggregate of minerals (minerals being inorganic solid material of specific chemical formula and crystaline structure), whereas coal is made of plant material primarily. Plants are not minerals, but geologists have made an exception for coal, since it is a natural earth solid material that is best characterized as a rock versus anything else we could classify it as, such as life, water, or air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://docsbay.net/introduction-to-types-and-classification-of-rocks&quot; rel=&quot;nofollow noreferrer&quot;&gt;INTRODUCTION TO TYPES AND CLASSIFICATION OF ROCKS&lt;/a&gt; by Geoffrey Mibei Geothermal Development Company&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This purely organic sedimentary rock that forms mainly from plant&#xA;  debris. The plant debris usually accumulates in a swamp environment.&#xA;  Coal is combustible and is often mined for use as a fuel.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="17225" LastActivityDate="2019-06-28T03:47:38.830" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17320" PostTypeId="1" AcceptedAnswerId="17326" CreationDate="2019-06-28T04:03:59.870" Score="1" ViewCount="115" Body="&lt;p&gt;As every thalassologist knows, the ocean is filled with great streches of desert with no marine photosynthetic life. What would happen if, for each of these oceanic deserts, I densely filled them with solar and wind &quot;oil rigs&quot; with water fountains surrounding them that pump up volumes of deep oceanic water and jets them out of the water? Let's suppose these solar and wind rigs operated continually.&lt;/p&gt;&#xA;" OwnerUserId="17244" LastActivityDate="2019-07-04T16:52:14.090" Title="What would happen if I installed distributed water fountains in all of the ocean's dead zones?" Tags="|oceanography|climate-models|" AnswerCount="1" CommentCount="4" ClosedDate="2019-06-30T10:13:19.313" ContentLicense="CC BY-SA 4.0" />
  <row Id="17321" PostTypeId="1" CreationDate="2019-06-28T07:23:09.280" Score="3" ViewCount="76" Body="&lt;p&gt;I have gone through the link (&lt;a href=&quot;http://www2.mmm.ucar.edu/wrf/OnLineTutorial/compilation_tutorial.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www2.mmm.ucar.edu/wrf/OnLineTutorial/compilation_tutorial.php&lt;/a&gt;) to build wrf libraries. I installed netcdf v4.1.3, mpich v3.0.4, jasper v1.900.1, zlib v1.2.7, and libpng v1.2.50 on the server. However, I could not compile my WRF-chem v3.5 and got some errors. I also could not generate the ndown.exe, nup.exe, real.exe, and wrf.exe. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The link is my compile log file: &lt;a href=&quot;https://www.dropbox.com/s/egyfmw7rlhe8wn0/compile.log?dl=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;compile.log &lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was not sure if I missed any required libraries or did something wrong.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would anyone please kindly give me some suggestions on this issue?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks a lot in advance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regards,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Qianjin&lt;/p&gt;&#xA;" OwnerUserId="17245" LastEditorUserId="17245" LastEditDate="2019-06-28T17:25:49.563" LastActivityDate="2019-06-29T11:18:08.980" Title="Error of compiling the wrf-chem V3.5 model" Tags="|wrf-chem|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17322" PostTypeId="2" ParentId="17206" CreationDate="2019-06-28T09:41:11.367" Score="1" Body="&lt;p&gt;Potassium 40 has a half life of 1,300,000,000 years,  which means that within that time half of the 11 percent which you refer to will have decayed to form Argon 40. Potassium 40 has two modes of decay, which is unusual for a radioactive isotope. Only 11 percent of it becomes argon 40, the remaining 89 percent decays by a different mode and becomes Calcium 40. but there is no need for you to worry about Calcium 40, it is the 11 percent of K40 which becomes Argon 40 which is useful in dating ancient rocks. Fortunately geologists don't have to wait until it has completed one full half life for it to be useful. By assessing the amount of Argon which has accumulated within the material since it was ejected by volcanoes in pristine condition and had no Argon at all in it, geologists can get a rough idea of the age of the rocks. The potassium/argon method is very tricky to carry out and error can easily creep in.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-06-28T09:41:11.367" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17323" PostTypeId="2" ParentId="16787" CreationDate="2019-06-28T13:37:17.060" Score="3" Body="&lt;p&gt;Short answer because there was no ice cap there. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why does the hudson bay have lower gravity, &lt;a href=&quot;https://en.wikipedia.org/wiki/Post-glacial_rebound&quot; rel=&quot;nofollow noreferrer&quot;&gt;isostatic rebound&lt;/a&gt;, there used to be an icecap right there, several miles of ice. That pushed the continental crust further down in to the mantle, like a boat with a heavy load. Mantle is denser than continental crust. When the icecap melted the rock started to rebound but it takes a LONG time to return to equilibrium. Mantle is not a liquid is does not rebound quickly. Basically the weight of the ice displaced a portion of the mantle and much of that mantle is still displaced. until it completely rebounds there is less mass there than in places with no such displacement. We can even measure &lt;a href=&quot;https://www.ontariobeneathourfeet.com/rising-land-isostatic-rebound&quot; rel=&quot;nofollow noreferrer&quot;&gt;how fast&lt;/a&gt; it is rebounding, several millimeters per year. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a side note that is also why there is an ocean on top of continental crust right there, the land is still depressed below sea level. It should take the area about ~1,000,000 year to rebound but the glaciers only meted about 11,000 years ago. So in about 989,000 years there will no longer be a gravitation depression there because the rock will have returned to equilibrium. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But why does the western shore not have it, because there was no glacier there. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/pHnST.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pHnST.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2019-06-28T13:51:06.547" LastActivityDate="2019-06-28T13:51:06.547" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17324" PostTypeId="2" ParentId="17317" CreationDate="2019-06-28T15:03:48.363" Score="0" Body="&lt;p&gt;It has been proposed to &lt;a href=&quot;https://e360.yale.edu/features/urban-heat-can-white-roofs-help-cool-the-worlds-warming-cities&quot; rel=&quot;nofollow noreferrer&quot;&gt;paint dark rooftops and roads white&lt;/a&gt; to reflect solar energy back to space. This should also work for deserts, although sand already has a high albedo. Applying a sealer of the same colour would not make much difference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Conduction, convection and thermal radiation in sand has been studied by &lt;a href=&quot;https://pumas.gsfc.nasa.gov/files/11_14_07_1.doc&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA&lt;/a&gt;. See also &lt;a href=&quot;http://www.madsci.org/posts/archives/2003-10/1065121289.Es.r.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this post&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In daytime the sand is hottest at the surface and cooler below. If it is a horizontal surface there won't be convection, since hot air rises. Possibly there could be convection with uneven surfaces (dunes). I think petroleum geologists know how to calculate flow given permeability and pressure gradient.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2019-07-02T01:38:42.393" LastActivityDate="2019-07-02T01:38:42.393" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17326" PostTypeId="2" ParentId="17320" CreationDate="2019-06-28T22:53:16.783" Score="1" Body="&lt;p&gt;That sounds like a method to attempt to increase the global humidity level.  I'm not sure how many areas we're talking, or who large they are, but &amp;quot;all of&amp;quot; just sounds like a lot.  It's at least going to be a massive humidifier the way you've designed it.&lt;/p&gt;&#xA;&lt;p&gt;I would think if you want to achieve your goal without radically humidifying the air, it would probably work better to design your apparatus after aquarium aerators.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://sustainablebaltic.wordpress.com/2016/07/21/can-deep-water-oxygenation-bring-back-life-into-baltic-dead-zones/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Somebody is studying this idea in the Baltic Sea.&lt;/a&gt; (thank you &lt;a href=&quot;https://earthscience.stackexchange.com/users/6258/trond-hansen&quot;&gt;trond hansen&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A main threat for the Baltic is at first the human induced pollution through industries, agriculture, deforestation, private homes, shipping and tourism. Waste or erosion water due to these practices, contains lots of N and P that stimulate primary production. Also rising sea water temperatures due to global climate change make the oxygen availability even worse, since less O2 can be dissolved in warmer water (USGS, 2016). Moreover, also pharmaceutics or other artificial chemical substances that end up in waste water contribute for a great deal to the dead zones. Not directly by inducing primary production, but maybe even worse; the toxins they contain can either directly kill marine life or add up in the food chain and cause health troubles. Also reproductive success can be affected by certain chemicals.&lt;/p&gt;&#xA;&lt;p&gt;In an attempt to stop the eutrophication and bring back life into dead zones, Swedish scientist came up with the idea of engineered re-oxygenation of the Baltic’s ‘dead zones’. Pumping relatively oxygen rich water from the surface into deeper anoxic layers, hereby breaking through the oxycline and allowing the water to mix again, must safe the Baltic according to the BOX project (Forth, 2015).&lt;/p&gt;&#xA;&lt;p&gt;Facilitating nature to restore itself, instead of only focussing on banning the resources, could accelerate the battle against eutrophication in the Baltic. However, many scientists are sceptical about the idea. Prof. Conley (Lund University) mentions that there might be unforeseen consequences that could change the whole ecosystem. He also mentions that oxygenation could affect the reproductive success of some fish species. That’s indeed true, but Koster et al. (2005) found that increased O2 – levels actually improve the reproductive volume of at least cod, which thus makes it a benefit.&lt;/p&gt;&#xA;&lt;p&gt;Apart from the costs of the BOX project, another point for consideration is the fact that treating the consequences instead of the sources might cause ignorance to obligations that try to reduce waste dumping, since it will be cleaned anyway.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In areas that are devoid of life due to a eutropic cycle (excessive nutrients in the water triggered a population explosion, which consumed all available oxygen, so everything suffocated), it would probably be helpful, so long as the aeration reaches the perimeter of the area.&lt;/p&gt;&#xA;&lt;p&gt;However, if other pollution is involved, that changes things significantly.  Even if the initial death was due to eutrophication, developing life can be much more susceptible to toxic chemicals than mature life.  Because of this and other factors, what works for one part of the ocean may not work in other parts.&lt;/p&gt;&#xA;&lt;p&gt;It's also worth noting that dead zones are not confined just to the oceans.  &lt;a href=&quot;https://hctf.ca/lake-aeration-in-b-c-another-tool-in-the-toolbox-by-brian-chan/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Something like this is being done in small lakes in Canada&lt;/a&gt; (Thank you &lt;a href=&quot;https://earthscience.stackexchange.com/users/824/friddy&quot;&gt;Friddy&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Ecologically, many of these nutrient rich small lakes are classified as being in a eutrophic state. These lakes are typically shallow, with maximum depths of less than 50 ft and average depths of less than 15 ft. They are often landlocked or have only intermittent or seasonal stream connections. Because they are rich in nutrients, they are abundant in aquatic plants and invertebrates. Eutrophic lakes can be extremely productive and have the capability to grow trout and char very quickly and to large sizes. However, the same features that make accelerated growth possible in the summer can make it difficult for trout to survive over winter. Some of our most popular interior trout lakes are marginal in terms of their ability to support trout through the colder months due to a drop in dissolved oxygen levels Thousands of small trout lakes in BC’s interior freeze over for 4 to 6 months each winter. During that ice-covered period, the aquatic plants that grew through the open water seasons die off from lack of sunlight. Dissolved oxygen in the water is used up as this plant matter decomposes. As winter progresses, the volume of oxygenated water decreases to levels that become too low to support trout life, which results in a winterkill.&lt;/p&gt;&#xA;&lt;p&gt;There are also small lakes located in the coastal regions that suffer from severe oxygen depletion during the summer months. This affects the ability of trout to survive as well as having impacts on the quality of the water for domestic use and other forms of aquatic recreation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Their situation is quite different.  Rather than trying to resolve issues with pollution, they're using it to allow fish in ice-covered ponds to survive the winter.  There's also some lakes with issues during the summer the article doesn't go into detail about, which could be pollution or it could be natural eutrophication.  For the winter use case, it apparently works at two levels, as not only does it provide direct oxygenation of the water, but it also adds resistance to icing over directly above where the aeration is done, providing some surface that continues to be able to get oxygen from the air.&lt;/p&gt;&#xA;&lt;p&gt;Both linked articles explicitly state this is just one tool to solve one particular issue, not a solution for all pollution, fish survival, and water quality issues.&lt;/p&gt;&#xA;" OwnerUserId="17198" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-07-04T16:52:14.090" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17327" PostTypeId="1" CreationDate="2019-06-29T04:19:12.387" Score="2" ViewCount="31" Body="&lt;p&gt;The title seems self explanatory to me. I thought about it when I was looking at a geologic map of Utah, and it seemed to include an exceptional amount of time. I mean this in the sense that there weren't any enormous gaps in the record. So, is it Utah or a different state?&lt;/p&gt;&#xA;" OwnerUserId="17249" LastActivityDate="2019-06-29T04:19:12.387" Title="What US State has the most complete rock record?" Tags="|time|regional-geology|geologic-layers|age|" AnswerCount="0" CommentCount="5" ClosedDate="2019-07-02T12:34:22.500" ContentLicense="CC BY-SA 4.0" />
  <row Id="17332" PostTypeId="2" ParentId="7627" CreationDate="2019-06-29T22:12:06.077" Score="-7" Body="&lt;p&gt;Have a look at the distribution of all carbon on earth and maybe it will tell you something. Carbonaceous rocks all created in a marine environment account for 99.95% of all carbon on earth (some 100 million billion tons). The next largest source is in fact the current oceans with approximately 0.038% of the total and finally we get to fossil fuels with 0.01%.  It should be noted here that there is almost 4 times more carbon dissolved currently in ocean water than there is in all fossil fuels existing on Earth.  The next source would represent non marine plants and soil at 0.002% and finally our atmosphere that currently contains.0008%.  So, marine environments roughly contain 99.99% of all carbon on earth and they would have you believe that there is some sort of “delicate” balance between the atmosphere and the oceans.  Let’s face it the oceans of the world are and will always be the greatest carbon sink on earth.&lt;/p&gt;&#xA;" OwnerUserId="17129" LastActivityDate="2019-06-29T22:12:06.077" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17335" PostTypeId="2" ParentId="2604" CreationDate="2019-06-30T16:05:24.260" Score="-2" Body="&lt;p&gt;One thing that is being ignored in this discussion is the loss of the energy in one of nature's primary cooling systems. BY lowering the energy in wind we also lower the ability of wind to cool the world &lt;/p&gt;&#xA;" OwnerUserId="17262" LastActivityDate="2019-06-30T16:05:24.260" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17336" PostTypeId="1" AcceptedAnswerId="17345" CreationDate="2019-06-30T17:39:35.863" Score="1" ViewCount="51" Body="&lt;p&gt;For a while I have been working with gypsum I mined from a site in Utah, and I realized how low the temperature is to turn it into plaster, so I was wandering; has there ever been any cases of large deposits of gypsum being naturally heated into plaster and coming in contact with water?&lt;/p&gt;&#xA;" OwnerUserId="7151" LastActivityDate="2019-07-01T15:26:01.927" Title="If gypsum turns into plaster around 210 F, is there any natural plaster deposits or formations out there?" Tags="|rocks|water|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17337" PostTypeId="1" AcceptedAnswerId="17344" CreationDate="2019-06-30T19:40:10.237" Score="4" ViewCount="318" Body="&lt;p&gt;Quite simply what is the highest point above sea level that is right on the equator, I figured it would be a mountain in the Ecuadorian Andes but the Kenyan highlands look to be a likely candidate as well. I've tried to find it but I simply can't find a map that has the equator and the altitude in a highly accurate format and resolution anywhere.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="10735" LastEditDate="2019-07-07T12:12:15.140" LastActivityDate="2019-07-07T12:12:15.140" Title="How far above sea level can you get on the equator?" Tags="|geography|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17339" PostTypeId="1" CreationDate="2019-07-01T04:28:32.313" Score="1" ViewCount="178" Body="&lt;p&gt;I've found some diagrams of the Oregon Coast Range, but they are very basic. An friend said he thinks there is limestone deep underground, but my understanding of the formation of these mountains is that there is not. Where can I find information to settle this question? (or, if you know the answer, I'd be glad to hear it)&lt;/p&gt;&#xA;" OwnerUserId="17265" LastActivityDate="2019-07-01T10:48:08.457" Title="Is there limestone under the Oregon Coast Range?" Tags="|geology|limestone|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17341" PostTypeId="2" ParentId="17337" CreationDate="2019-07-01T08:44:20.353" Score="1" Body="&lt;p&gt;You're right about Mount Kenya, which is more or less on the equator and is about 5,000 metres above sea level. Mount Kinabalu in northern Borneo (Malaysia) is also on the equator, but only 4,000 metres high. Kilimanjaro, next door to Kenya in Tanzania, is about 6,ooo metres, but further from the equator than Mount Kenya&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-01T08:44:20.353" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17342" PostTypeId="2" ParentId="17339" CreationDate="2019-07-01T10:48:08.457" Score="1" Body="&lt;p&gt;I'm not familiar with the Oregon Coast Range, but limestone is such a ubiquitous and widespread rock that your friend is almost certainly right. For strata to be limestone, they need to have been under the sea when they were laid down. The fact that some are found today near the tops of mountains only means that plate movements have uplifted them since they were formed. They might easily have become overlaid with igneous rock, volcanic tuffs, sandstone etc,but if you go down deep enough the probability is that you'll find limestone somewhere. You usually don't have to go down very far, and there are usually exposures that reveal it. Limestone (calcium carbonate) is often a good place to find fossils.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-01T10:48:08.457" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17343" PostTypeId="1" AcceptedAnswerId="17356" CreationDate="2019-07-01T13:23:32.390" Score="3" ViewCount="1195" Body="&lt;p&gt;This article &lt;a href=&quot;https://www.infoplease.com/math-science/weather/lowest-recorded-temperatures&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lowest recorded temperatures&lt;/a&gt; lists a -89 Degrees Celsius in Vostok, Antartica as the lowest recorded temperature. However, this other article &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_weather_records&quot; rel=&quot;nofollow noreferrer&quot;&gt;List of weather records&lt;/a&gt; lists a −93.2 °C (−135.8 °F) on 10 August 2010, at   81.8°S 59.3°E. measured by Satellite. And this other article &lt;a href=&quot;https://www.forbes.com/sites/trevornace/2018/06/28/its-almost-like-another-planet-coldest-temperature-on-earth-recorded-in-antarctica/#562a37ca4054&quot; rel=&quot;nofollow noreferrer&quot;&gt;Coldest temperature on Earth in Antarctica&lt;/a&gt; lists a -97,8 °C , also using satellite measurements. Which one is the lowest temperature ever recorded on the surface of Earth then? Are satellite measurements reliable and do they count?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastActivityDate="2019-07-02T10:49:57.607" Title="What was the lowest temperature ever recorded on the surface of Earth?" Tags="|climate|temperature|measurements|extreme-weather|field-measurements|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17344" PostTypeId="2" ParentId="17337" CreationDate="2019-07-01T15:06:09.630" Score="9" Body="&lt;p&gt;I would assume that's the highest point on the equator you talking about, so The highest point on the Equator is at the elevation of 4,690 metres (15,387 ft), at 0°0′0″N 77°59′31″W, found on the southern slopes of &lt;a href=&quot;https://en.wikipedia.org/wiki/Cayambe_(volcano)&quot; rel=&quot;noreferrer&quot;&gt;Volcán Cayambe&lt;/a&gt; [summit 5,790 metres (18,996 ft)] in Ecuador. This is slightly above the snow line and is the only place on the Equator where snow lies on the ground.&lt;/p&gt;&#xA;" OwnerUserId="17260" LastEditorUserId="2470" LastEditDate="2019-07-01T17:21:00.657" LastActivityDate="2019-07-01T17:21:00.657" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17345" PostTypeId="2" ParentId="17336" CreationDate="2019-07-01T15:26:01.927" Score="0" Body="&lt;p&gt;Water is removed from gypsum hydrate about 300 F+ making it dry powder gypsum. Water is added to gypsum to make &quot;plaster of Paris&quot; , no particular temperature is involved. Not sure it answers the question , but gypsum commonly deposits in oil production tubing. The produced oil/water/gas  mix cools as it comes up the well tubing and deposits in the tubing,; very difficult to prevent or remove.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2019-07-01T15:26:01.927" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17349" PostTypeId="2" ParentId="17343" CreationDate="2019-07-02T01:22:37.003" Score="0" Body="&lt;p&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2018GL078133&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ultralow Surface Temperatures in East Antarctica&#xA;From Satellite Thermal Infrared Mapping:&#xA;The Coldest Places on Earth&lt;/a&gt; p. 6127 says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Validation studies of MODIS c5 and c6 LST for nonpolar regions, while limited, suggest that the surface temperature data are generally within 1 °C of the in situ measured thermal emission temperature (Wan, 2014),&#xA;  although the validation did not extend to this temperature range or surface type.  &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The coldest temperatures seem to be surface snow temperature. 2M air temperatures are a couple of degrees warmer.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-07-02T01:22:37.003" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17351" PostTypeId="1" CreationDate="2019-07-02T03:50:15.520" Score="1" ViewCount="65" Body="&lt;p&gt;I have a dataset of sample concentrations of several ions/elements (Ca 2+, SO4 2-, K +, S, Ca, V, etc.) from an ice core which I am using to detect volcanic eruptions. The raw version of the dataset has a high resolution (many samples per year) for recent years and an increasingly low resolution for older samples. I also have a resampled version of the dataset, where the data points are interpolated at a regular time interval (quarter-year frequency), for my other analyses, as most types of time series analyses assume that the data is collected at regular time intervals. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to perform an EOF (Empirical Orthogonal Function) analysis on the dataset, because a mode that has a high sulfate loading may represent volcanic activity. I read somewhere (sorry, I don't remember where exactly, but I think it was on Cross Validated) that the even spacing of the time series is not required for EOF/ Principal Component Analysis, but I am not sure why.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now my question is: for my EOF analysis, should I use the raw data (the unevenly-spaced time series) for maximum precision of my results, or should I use the resampled data (linearly interpolated data points at a quarter year frequency) in order to avoid all the problems entailed by an uneven time series? (I am not sure exactly what those are, but I imagine problems like overestimating trends based on recent observations or underestimating trends present in older observations)&lt;/p&gt;&#xA;" OwnerUserId="17272" LastActivityDate="2019-07-02T03:50:15.520" Title="Should I perform EOF analysis on an unevenly-spaced time series?" Tags="|geology|glaciology|volcanic-eruption|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17355" PostTypeId="1" CreationDate="2019-07-02T10:32:50.253" Score="1" ViewCount="43" Body="&lt;p&gt;I'm trying to understand the atmospheric greenhouse effect. If CO2 absorbs lots of IR radiation emitted from the Earth's surface, does it not also shield the same wavelength radiation that is coming from the sun? Would this shielding not have a 'cooling' effect. Does CO2 block incoming IR from the sun?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the ratio of energy absorbed by atmospheric CO2 from IR coming from the Earth vs directly from the Sun?&lt;/p&gt;&#xA;" OwnerUserId="17275" LastEditorUserId="17275" LastEditDate="2019-07-02T13:07:58.503" LastActivityDate="2019-07-02T13:07:58.503" Title="What is the ratio of energy absorbed by atmospheric CO2 from IR coming from the Earth vs directly from the Sun" Tags="|co2|greenhouse-gases|" AnswerCount="0" CommentCount="6" ClosedDate="2019-07-02T15:10:11.973" ContentLicense="CC BY-SA 4.0" />
  <row Id="17356" PostTypeId="2" ParentId="17343" CreationDate="2019-07-02T10:49:57.607" Score="3" Body="&lt;p&gt;The wikipedia article &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_weather_records&quot; rel=&quot;nofollow noreferrer&quot;&gt;List of weather records&lt;/a&gt; explicitly states&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This list does not include remotely sensed observations such as satellite measurements, since those values are not considered official records.[1]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Reference 1 in that article, a web archive link to a page on &lt;a href=&quot;https://web.archive.org/web/20131213113854/http://wmo.asu.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;World Meteorological Organization Global Weather &amp;amp; Climate Extremes&lt;/a&gt;, adds that (emphasis mine)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Although claims of a &quot;world-record coldest temperature&quot; have been made for a remote-sensed location in Antarctica, the WMO official coldest temperature remains -89.2°C (-128.5°F) recorded on 21/7/1983 at Vostok, Antarctica. Official weather measurements are made at using standard equipment at a fixed height of between 1.25 m (4 ft 1 in) and 2 m (6 ft 7 in) above the ground for a fixed location over a specific length-of-record. &lt;strong&gt;Remoted-sensed values of temperature are not at this time regarded as official weather measurements.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There are many reasons why remote sensed temperature values (especially extreme ones) should not be considered as official with regard to record temperatures. First and foremost, those remotely sensed values are not measuring temperature. They instead measure proxies for temperature in the form of intensities of electromagnetic radiation in various frequency bands in the thermal infrared. The surface temperature is derived from these observations by a complex set of algorithms that make various assumptions regarding the nature of the sensed data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These algorithms need to be calibrated against ground truth. These is no ground truth data for temperatures that low. The interpreted data were well outside the sensors calibrated rate. Moreover, the &quot;ground truth&quot; data is actually the recorded temperature at 1.25 meters to 2 meters above the ground. Official weather stations are supposed to be slightly elevated to avoid boundary layer effects. The sensed data on the other hand are primarily  a result of surface temperatures, confounded by the fact that snow is a lousy thermal infrared emitter (&quot;a good reflector is a lousy emitter&quot;) and confounded by contributions from the atmosphere between the surface and the satellite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, those satellite readings almost certainly do indicate temperatures well below the reading at Vostok that officially counts as the lowest temperature recorded on the Earth.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2019-07-02T10:49:57.607" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17357" PostTypeId="2" ParentId="17213" CreationDate="2019-07-02T12:15:47.330" Score="1" Body="&lt;p&gt;I have found an archive of small-scale charts encompassing part of Africa &lt;a href=&quot;https://www.wetterzentrale.de/reanalysis.php?jaar=2019&amp;amp;maand=1&amp;amp;dag=11&amp;amp;uur=000&amp;amp;var=45&amp;amp;map=1&amp;amp;model=nws&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="17152" LastActivityDate="2019-07-02T12:15:47.330" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17358" PostTypeId="1" AcceptedAnswerId="17359" CreationDate="2019-07-02T13:04:44.407" Score="2" ViewCount="35" Body="&lt;p&gt;If sea-levels rise, does the Earth's atmosphere extend to the same distance out to space, with the pressure increasing, or does it expand?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If sea levels rose 10m, how much change would there be to the volume of the atmosphere?&lt;/p&gt;&#xA;" OwnerUserId="17275" LastActivityDate="2019-07-02T16:30:42.470" Title="What is the effect of sea-level changes on the extent of the Earth's atmosphere?" Tags="|atmosphere|sea-level|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17359" PostTypeId="2" ParentId="17358" CreationDate="2019-07-02T15:10:40.643" Score="0" Body="&lt;p&gt;90% of earths atmosphere is from 0-10000m this means an increase of 0,001%.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But this is wrong the melting ice will be replaced by air so there will not be any change in volume.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ice have a larger volume than water have so the result will be a very slight drop in air volume.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have not taken hight for air under pressure in the ice here but you get the point,You are only redistributing material on our planet so nothing is added or removed from the system.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6258" LastEditDate="2019-07-02T16:30:42.470" LastActivityDate="2019-07-02T16:30:42.470" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17363" PostTypeId="1" CreationDate="2019-07-02T23:01:41.797" Score="5" ViewCount="681" Body="&lt;p&gt;I'm wondering by how much the gravitation effects, tides etc caused by the moon (and other energy such as moonlight IR) increase the surface temperature of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So how much warmer than the blackbody temperature is Earth due to energy imparted by the Moon? Or putting it the otherway, how much colder would Earth be if there was no Moon.&lt;/p&gt;&#xA;" OwnerUserId="17275" LastActivityDate="2019-07-02T23:52:55.507" Title="How much energy does the Moon transfer to the Earth, does this affect the Earth's surface temperature?" Tags="|temperature|moon|gravity|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17364" PostTypeId="2" ParentId="17363" CreationDate="2019-07-02T23:52:55.507" Score="3" Body="&lt;p&gt;According to a slightly old estimate, the total power input from the tides is approx 3.7 TW [1]. Of this about 3.2 TW is from the moon (the rest is from the sun). Most of it goes into moving the oceans around, and some of it into doing the same with the land - but both ultimately end up as heat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question of how much this power affects the temperature of the earth is beyond my expertise, but it's a small amount of power at a planetary scale. Some very approximate comparisons:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Tidal power from the moon: 3.2 TW [1] &lt;/li&gt;&#xA;&lt;li&gt;Total global electricity consumption: 3-4 TW&lt;/li&gt;&#xA;&lt;li&gt;Geothermal heat flow from the earth's interior: 30 TW [1]&lt;/li&gt;&#xA;&lt;li&gt;Total sunlight hitting Earth (outside the atmosphere): ~175,000 TW [1,2]&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;[1] Munk &amp;amp; Wunsch 1998; &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0967063798000703&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.sciencedirect.com/science/article/pii/S0967063798000703&lt;/a&gt; - probably paywalled.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[2] &lt;a href=&quot;https://www.e-education.psu.edu/earth103/node/1004&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.e-education.psu.edu/earth103/node/1004&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-07-02T23:52:55.507" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="17365" PostTypeId="2" ParentId="17311" CreationDate="2019-07-03T01:35:37.753" Score="3" Body="&lt;p&gt;No, simply because we cannot access it and the methods for understanding it are essentially indirect geochemical and geophysical measurements (mostly experimental petrology and wave propagation experiments). We only talk about models, so far. So much so anything deeper than the crust - to be more precise, anything &lt;em&gt;but&lt;/em&gt; upper continental crust is either measured indirectly - i.e. we have no access. The mantle? Mostly theoretical with the help of xenoliths (rocks from the mantle that are brought up by ascending magma). &lt;/p&gt;&#xA;" OwnerUserId="13211" LastActivityDate="2019-07-03T01:35:37.753" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17366" PostTypeId="1" CreationDate="2019-07-03T01:50:04.823" Score="2" ViewCount="3463" Body="&lt;p&gt;What is the main difference between &lt;strong&gt;dew&lt;/strong&gt; and &lt;strong&gt;rain&lt;/strong&gt;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would it be correct if we say that rain is done in the upper troposphere while dew done in the lower troposphere? Or there are better definitions for the main difference between them? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hgriR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hgriR.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7190" LastActivityDate="2019-07-09T03:31:30.740" Title="What is the difference between dew and rain?" Tags="|meteorology|rain|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17367" PostTypeId="2" ParentId="17366" CreationDate="2019-07-03T02:57:38.957" Score="2" Body="&lt;p&gt;Both are condensation, but dew forms directly on a solid surface, rain forms in the air. In theory you could form dew in any part of the atmosphere if you had something for it to form on. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2019-07-03T02:57:38.957" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17368" PostTypeId="1" CreationDate="2019-07-03T11:59:12.743" Score="1" ViewCount="37" Body="&lt;p&gt;I'm currently conducting research using Satellite/Weather/Soil (Mostly Sentinel-2 Satellite Imagery) Data to Model Smallholder Farms and their dynamics before Planting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Key to my progress is to find a way to Assess the quality of farmlands soil right after Ploughing based on the available data. I was looking for either remote sensing-based or Soil-based indices that quantify the Quality of plowed lands.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any such indices that I can infer using Sentinel/Landsat-based Imagery or Soil/Weather properties?&lt;/p&gt;&#xA;" OwnerUserId="17281" LastActivityDate="2019-07-03T11:59:12.743" Title="What's a Good Soil Quality Index for Plowed Farm Lands?" Tags="|soil|agriculture|satellites|soil-moisture|soil-science|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="17369" PostTypeId="2" ParentId="17366" CreationDate="2019-07-03T15:13:59.133" Score="5" Body="&lt;p&gt;Dew is condensate that forms on the surface, usually by the surface cooling to a temperature below the dew point of the air. Thus the water vapr accumulates onto the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rain is formed by &lt;a href=&quot;https://www.e-education.psu.edu/meteo300/node/780&quot; rel=&quot;noreferrer&quot;&gt;Collision-Coalescence&lt;/a&gt; or the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Bergeron-findeisen_process&quot; rel=&quot;noreferrer&quot;&gt;Bergeron-Findelsen process&lt;/a&gt;. The cloud droplets are formed by the condensation of water vapor on aerosols, when the air reaches supersaturation via the &lt;a href=&quot;https://www.e-education.psu.edu/meteo300/node/676&quot; rel=&quot;noreferrer&quot;&gt;Kelvin Effect&lt;/a&gt; and &lt;a href=&quot;https://www.e-education.psu.edu/meteo300/node/677&quot; rel=&quot;noreferrer&quot;&gt;Raoult Effect&lt;/a&gt; (which makes up &lt;a href=&quot;https://www.e-education.psu.edu/meteo300/node/678&quot; rel=&quot;noreferrer&quot;&gt;Kohler Theory&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2019-07-03T15:13:59.133" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17370" PostTypeId="1" CreationDate="2019-07-03T16:05:02.420" Score="3" ViewCount="145" Body="&lt;p&gt;If a rock is tapered, does the tapered point indicate the glacier direction?&lt;/p&gt;&#xA;" OwnerUserId="17284" LastEditorDisplayName="user20559" LastEditDate="2021-11-20T08:02:29.033" LastActivityDate="2021-12-20T09:00:35.110" Title="Can the shape and orientation of a large glacial rock deposit indicate glacial flow direction" Tags="|stratigraphy|glaciation|cryosphere|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17371" PostTypeId="2" ParentId="17314" CreationDate="2019-07-03T20:09:05.587" Score="1" Body="&lt;p&gt;I assume that the sentence in the book mainly refers to subsidence as an adiabatic process. This sinking motion has a maximum which is at a height well above the surface, simply for the reason that air flow can not penetrate the earth's surface. Therefore maximum adiabatic heating rates occur well above the surface as well. The precise height where this occurs depends on the height of the planetary boundary layer, which itself depends on many more both adiabatic and diabatic effects.&lt;/p&gt;&#xA;" OwnerUserId="13524" LastEditorUserId="13524" LastEditDate="2019-08-09T07:59:39.070" LastActivityDate="2019-08-09T07:59:39.070" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17372" PostTypeId="2" ParentId="17370" CreationDate="2019-07-03T21:30:36.737" Score="1" Body="&lt;p&gt;Yes, it can. There are large, elongated mounds of till carried by the glacier as it advanced and left behind as it retreated. These mounds are called drumlins. Their long axis points along the track of the now vanished glacier. They are wider, higher and steeper at the end which points toward the glacier's source and taper away gradually at the opposite end, which points away from the source. They vary in size, but are sometimes a few hundred yards in length and about 50 or 60 feet high. Most are smaller. Sometimes there is a group of them, called a drumlin field. Glaciers also leave behind mounds of debris transverse to their track called terminal moraines. A terminal moraine is formed where the end of the glacier was stationary for a while when it was retreating, and there may be several of them at intervals along the retreating glacier's track.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-03T21:30:36.737" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17373" PostTypeId="2" ParentId="17277" CreationDate="2019-07-03T22:10:44.190" Score="13" Body="&lt;p&gt;Supplementing Wolfgang's answer, here's &lt;a href=&quot;https://oceanservice.noaa.gov/facts/atlantis.html&quot; rel=&quot;noreferrer&quot;&gt;a National Oceanographic and Atmospheric Administration story&lt;/a&gt; that talks about the appearance of ocean-bottom artifacts:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;With legions of people around the world now exploring the seafloor,&#xA;  many are noticing locations along the ocean bottom marked by&#xA;  mysterious formations of grid-like artifacts. These formations look&#xA;  like they were made by humans, leading many to ask if these areas&#xA;  could be lost cities or underwater streets.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;While these formations are human-made, they are only made of data. In&#xA;  other words, there are no physical lines on the ocean floor. These&#xA;  lines are artifacts of the ocean floor mapping process.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://scripps.ucsd.edu/news/around-pier-new-global-seafloor-map-incorporated-google-ocean&quot; rel=&quot;noreferrer&quot;&gt;Much if not all of Google Earth's seafloor data comes via Scripps Institution of Oceanography&lt;/a&gt;, which combines both gravity data from satellite missions and sonar scans from sources that make their records available. Oceanographic vessels tend to travel in straight lines and/or criss-cross patterns and collect high-quality sonar data while they're doing it, resulting in strips of detail that look much different from the surround sea floor.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2019-07-03T22:10:44.190" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17375" PostTypeId="1" AcceptedAnswerId="17935" CreationDate="2019-07-05T10:09:17.953" Score="5" ViewCount="536" Body="&lt;p&gt;The Beta plane approximation put me in confusion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Beta_plane&quot; rel=&quot;noreferrer&quot;&gt;Beta plane approximation&lt;/a&gt; explain me how the Coriolis parameter changes with latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Beta_plane&quot; rel=&quot;noreferrer&quot;&gt;Beta parameter&lt;/a&gt; changes with the cos(latitude) but this is refers to the equator or my latitude (arbitrary point)? &#xA;If i go southward latitude decrease so cos(latitude) is max at the equator but the Coriolis parameter is usually minimum at the equator. I made confusion with their relationship.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Beta plane approximation is related at the Beta effect or is it the same?&#xA;I don't understand its implication on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Boundary_current#Western_intensification&quot; rel=&quot;noreferrer&quot;&gt;westward intensification&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you in advance.&lt;/p&gt;&#xA;" OwnerUserId="17200" LastActivityDate="2019-09-07T10:24:30.720" Title="Beta plane approximation: variation of Coriolis parameter" Tags="|oceanography|coriolis|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17376" PostTypeId="1" AcceptedAnswerId="17382" CreationDate="2019-07-05T10:10:47.903" Score="1" ViewCount="220" Body="&lt;p&gt;Recently I am tasked to create a POC on detection of patterns using a neural &lt;a href=&quot;https://i.stack.imgur.com/7tv4v.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7tv4v.jpg&quot; alt=&quot;network&quot;&gt;&lt;/a&gt;.&#xA;But I am from a computer science background so I know about neural networks but I don't have any knowledge about geology or how to read those surveys.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone guide me on how to read these graphs or what do the colors mean in the image.&lt;/p&gt;&#xA;" OwnerUserId="17295" LastActivityDate="2019-07-06T07:16:43.763" Title="How to read Seismic Survey?" Tags="|seismic|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17378" PostTypeId="1" CreationDate="2019-07-05T17:01:07.483" Score="3" ViewCount="1159" Body="&lt;p&gt;I'm not familiar with these kinds of data sets but I'm looking for some data for a project I'm working on. Essentially I would like multiple time series of seismic data from different stations over different periods. Is this sort of data freely available somewhere in a friendly CSV format? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for any help.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Luke&lt;/p&gt;&#xA;" OwnerUserId="17060" LastActivityDate="2019-08-10T11:55:20.890" Title="Where can I download historical sesimic data in CSV/Excel format for processing in R?" Tags="|seismology|open-data|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17379" PostTypeId="1" CreationDate="2019-07-05T20:03:39.203" Score="2" ViewCount="122" Body="&lt;p&gt;Today (July 5th, 2019 just before 8 pm KST), along the Han River in Seoul, the &lt;strong&gt;surface of the sun&lt;/strong&gt; could be viewed &lt;strong&gt;with my naked eye&lt;/strong&gt; &lt;em&gt;(no protection needed)&lt;/em&gt;, and this was safe on the eyes. It appeared much redder and it wasn't bright at all. Also, there was no visible &quot;fog&quot; that blocked the view of the sun in my vicinity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;I am curious about the conditions needed to create this phenomenon&lt;/strong&gt; A possible use-case of an answer could mean the possibility to better predict when I should go view the sunset over the Han River in Seoul. It's beautiful!&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Past Related Topics&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/7663/17299&quot;&gt;Why can I look directly at the sun during a sunset but not at noon?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;This is different from my question&lt;/strong&gt; as, while you can still look at it, it is still slightly harmful to your eyes. It can still create some visual artifacts in your vision after you stop staring for even a few seconds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sun I saw today at sunset was &lt;strong&gt;not bright at all&lt;/strong&gt;. You could stare at the sun for minutes, tens of minutes, etc without any visual impairments. Also, the sun was red in color. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There appears to be at least one more additional condition needed to produce the visual I saw today.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;My Thoughts&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Just to be clear, this seems to go beyond the physics of the &lt;strong&gt;standard sunset&lt;/strong&gt;. To me, there seem to be 3 atmospheric conditions that are playing their part in this phenomenon. The first 2 will give you the standard sunset with its beautiful colors. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;strong&gt;Rayleigh Scattering.&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;The longer distance light travels along the Horizon.&lt;/strong&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;This enhances Rayleigh Scattering and gives the colors of the sunset.&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;???&lt;/strong&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Either this &lt;strong&gt;enhances&lt;/strong&gt; Rayleigh Scattering more along the horizon (enhances #2)&lt;/li&gt;&#xA;&lt;li&gt;Or it's a &lt;strong&gt;separate phenomenon&lt;/strong&gt; completely&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;When combined with #1 and #2, allows people to view the surface of the sun without protection!&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;h2&gt;More Background Information&lt;/h2&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;I have seen this phenomenon a few times before in Seoul. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Phenomenon never occurred in the US in my hometown for me&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Hometown is farther north than Seoul. &lt;/li&gt;&#xA;&lt;li&gt;Harbin, China would be a similar latitude.&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;I have never seen this phenomenon during the winter.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;It's possible it has happened, but I didn't see it!&lt;/li&gt;&#xA;&lt;li&gt;It's only occurred in the Spring and Summer for me.&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;While the afternoon was thicker in air pollution, I believe around sunset the air pollution nearby was much more clear.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Around this time (if UTC conversion were correct), there was a thicker air pollution mass around China and the northern part of the Yellow Sea.&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Sun sets in the West, and any air conditions to the west could affect the sunset.&lt;/li&gt;&#xA;&lt;li&gt;Is that in line-of-sight? Did the air pollution reach higher in the atmosphere around China? With line-of-sight, that would be around 10 - 60km in the air over the Yellow Sea and China.&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;h2&gt;Analysis&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;With #1 and #2 directly above, the longer distance that light travels along the horizon during (1) &lt;em&gt;the sunset&lt;/em&gt; and (2) &lt;em&gt;the winter in the Northern Hemisphere&lt;/em&gt; doesn't seem to play a big part. Otherwise, I should see this a lot in the winter around sunset. I don't, and I never have. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can air pollution be clear nearby, yet block all the bright light rays farther away?&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Photo&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Here is a photo that can help show the conditions that were present at the time.  Please note that the sun appears much brighter in this picture than it was in-person. The sun was actually really dull red. As you can see, there were clouds, but I am trying to find maps that show the cloud coverage around that time, as I don't believe it was thick.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/jizSv.jpg&quot; width=&quot;500&quot; &gt;&lt;/p&gt;&#xA;" OwnerUserId="17299" LastEditorUserId="17299" LastEditDate="2019-07-05T20:44:24.637" LastActivityDate="2019-07-05T23:57:19.727" Title="Atmospheric conditions needed that blocks all bright light during sunsets and allows you to stare directly at the sun" Tags="|meteorology|atmosphere|air-pollution|sun|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17380" PostTypeId="2" ParentId="17379" CreationDate="2019-07-05T23:57:19.727" Score="1" Body="&lt;p&gt;I am familiar with this phenomenon. In London, in winter 1947, I remember being able to see sunspots with the naked eye. The sun was very orange, like the one in your photo. The reason I was able to see sunspots was,of course, that the London sky was polluted with fumes and the winter sun was low on the horizon, so the rays had a greater thickness of atmosphere to penetrate. Much of the short wavelengths were filtered out, while the longer, redder wavelengths were able to get through. Much the same thing seems to have happened when you took this photograph of Seoul. It is common knowledge that red wavelengths penetrate foggy or hazy atmospheric conditions better than shorter wavelengths.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-05T23:57:19.727" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17381" PostTypeId="1" CreationDate="2019-07-06T06:23:33.957" Score="5" ViewCount="964" Body="&lt;p&gt;I recently came over some numbers of &lt;a href=&quot;https://earthscience.stackexchange.com/questions/10160/co2-emissions-per-calorie-food&quot;&gt;GHGs released per energy in food produced&lt;/a&gt;, and the result is pretty flooring. I can see how animal-based food production is quite inefficient so let's ignore that for now and just look at plants.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example rice releases 2 kg carbon =  7.6 kg CO2-equivalents per 1000 kcal. This would actually mean that it is more environmentally friendly to drive a car 10 km than to bike 10 km on a rice-based diet, because biking burns around 300 kcal = ~2.28 kg CO2e, while a normal compact car burns 0.5 liters of gasoline &lt;a href=&quot;https://www.eea.europa.eu/signals/signals-2017/infographics/range-of-life-cycle-co2/view&quot; rel=&quot;noreferrer&quot;&gt;= ~1.9  kg CO2e&lt;/a&gt;. Are my numbers wrong? If not, how can this be?&lt;/p&gt;&#xA;" OwnerUserId="17302" LastActivityDate="2019-07-08T03:11:01.577" Title="How does agriculture release so much greenhouse gas?" Tags="|climate-change|agriculture|greenhouse-gases|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17382" PostTypeId="2" ParentId="17376" CreationDate="2019-07-06T07:16:43.763" Score="4" Body="&lt;p&gt;Oh boy, a thorough understanding will be difficult, because reading these things to their full potential can take 10+ years of experience... If you really want to dive into it, read a book on seismic (exploration) geophysics -- this is the main reference book in the field: &lt;a href=&quot;https://wiki.seg.org/wiki/Seismic_Data_Analysis&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://wiki.seg.org/wiki/Seismic_Data_Analysis&lt;/a&gt; .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The best way to understand the picture is to understand how the data came to be:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The subsurface consists of layers (and other shapes) of varying density and compressibility, leading to different wave speeds. For example, mechanical vibrations (=seismic waves) move with a different speed through sand than through granite, ...&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Take a famous model, the Marmousi model:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ndcwq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ndcwq.png&quot; alt=&quot;marmousi&quot;&gt;&lt;/a&gt;&#xA;This model has variations in the velocity (low velocities at the top, faster towards the bottom), with all kinds of geological features: faults, folds, uncomformities, ...&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The seismic company creates an explosion to create a seismic wave that propagates through the model, and at every interface where the seismic properties change (called the 'acoustic impedance'), a reflection is created. However, the company only records the signal at the top, the same level where it created the seismic wave:&#xA;&lt;a href=&quot;https://www.youtube.com/watch?v=U0hT9vO_oHA&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=U0hT9vO_oHA&lt;/a&gt; ; on the left you see the wave move into the Marmousi model, reflecting off every impedance change; on the right you see the data that is recorded at the receivers, with the color specifying a contraction or an extension (any wave creates both extension and contraction, never just one: &lt;a href=&quot;https://www.youtube.com/watch?v=2rYjlVPU9U4&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=2rYjlVPU9U4&lt;/a&gt; )&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Actually, the recording consists of individual receivers which record individual traces, it's just interpolated and turned into a black-and-white image in the video:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/5k5VC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5k5VC.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Eventually, through careful and computationally intense algorithms, the recorded data is turned into a stack and is 'migrated', such that the recorded data is 'imaged' at the approximate location of the reflections in the subsurface. When still using the individual traces you get:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/IiEQ9.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IiEQ9.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;The traces are now SO close together that it almost becomes a black and white image. And this is where the colors come in, the same section may be displayed as:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/qAiUF.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qAiUF.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;where the positive (right-ward, black) trace has been replaced with RED, and the negative (left-ward, white) move of the trace has been replaced with BLUE, and white as the intermediate color.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;So, for the Marmousi model, people can make these type of images:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/FCkff.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FCkff.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;you see how it looks similar to the true model -- but is still generally much noisier, particularly for deeper reflections further down the image? In principal, the red/blue color corresponds to an increase or a decrease in acoustic impedance, but it's sometimes tough to see these things clearly...&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ndcwq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ndcwq.png&quot; alt=&quot;marmousi&quot;&gt;&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Hence, the image that you have is probably a migrated stack, varying from extremely light blue to dark blue to grey to red to yellow. The z axis corresponds to (approximate) depth, the x axis corresponds to receiver positions/offsets. All the lines are contrasts between rock types that have been geologically deformed, either a positive or negative impedance contrast. Features of interest to geologists are too numerous to mention, but of basic interest are (1) tracking a whole line over the entire image to see the continuity of a single reflecting unit, (2) seeing a fault -- where a reflector breaks and picks up a bit below, (3) finding really intense ('bright') spots in the data, (4) finding salt, e.g., as done here &lt;a href=&quot;https://www.kaggle.com/c/tgs-salt-identification-challenge/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.kaggle.com/c/tgs-salt-identification-challenge/&lt;/a&gt; ...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But yeah, demand more information from whoever wants you to do this work about what features are of interest because there's too much in the image to just blindly start learning things...&lt;/p&gt;&#xA;" OwnerUserId="12155" LastActivityDate="2019-07-06T07:16:43.763" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17383" PostTypeId="2" ParentId="17381" CreationDate="2019-07-06T10:41:20.963" Score="-1" Body="&lt;p&gt;If you want to exclude animals, better to say why does arable farming release so much greenhouse gas. I have heard the argument about rice fields before, and it may well be true, but you have to remember that arable farming is almost carbon neutral. It removes CO2 from the air and gives it back in the ways you mention. You could even have tractors powered by biofuel, and some tractors already are. There is a very small downside, which is that plants, rice fields in particular, return a small amount of the carbon in the form of methane, which is a more potent greenhouse gas. Whatever the arguments against arable, it is more environment friendly than livestock. One thing you are never going to do is persuade people to give up eating. You aren't even going to persuade many to give up eating rice. With regard to livestock farming, its effect is not as damaging as some people allege, because you need to remember that the Earth has always had vast herds of herbivores releasing methane, it's just that the previous herds of bison etc have now largely been replaced by cattle.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-06T10:41:20.963" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17385" PostTypeId="1" CreationDate="2019-07-06T23:14:08.880" Score="3" ViewCount="348" Body="&lt;p&gt;I'm aware that PDEs, linear algebra, numerical analysis and such are staples of most applied mathematical endeavors. I want to know if there are other areas of &quot;higher&quot; mathematics that have useful applications in climate science (like topology, measure theory, Riemannian geometry, etc) or whether the things I mentioned first are the only really important ones. Thanks. &lt;/p&gt;&#xA;" OwnerUserId="17305" LastActivityDate="2019-07-07T04:47:59.367" Title="What types of high-level mathematics are useful in doing climate modelling/meteorology?" Tags="|climate|models|mathematics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17386" PostTypeId="2" ParentId="17385" CreationDate="2019-07-07T01:58:21.857" Score="5" Body="&lt;p&gt;The question may generate primarily opinion based answers but while it is open one would like to present the following information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the outset most of the people I know in the field work in &lt;a href=&quot;https://en.wikipedia.org/wiki/Numerical_weather_prediction&quot; rel=&quot;noreferrer&quot;&gt;NWP&lt;/a&gt; and the reason people avoid higher mathematics(by that I mean looking for analytical solutions or pure math based projects such as you mention topology or Riemannian geometry) is because of the issue of jobs after completion of their respective Ph.ds and post docs. More of the recent advances use approaches from statistics and &lt;a href=&quot;https://en.wikipedia.org/wiki/Big_data&quot; rel=&quot;noreferrer&quot;&gt;Big Data&lt;/a&gt; and that is because of the massive amounts of data that is available on a daily basis.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Presuming one wants to move on a &quot;path&quot; in academia then there is this application of topology in meteorology - &lt;a href=&quot;https://en.wikipedia.org/wiki/Hairy_ball_theorem&quot; rel=&quot;noreferrer&quot;&gt;Hairy ball theorem &lt;/a&gt; and this book should provide more information on the topic &lt;a href=&quot;https://www.springer.com/gp/book/9781402002069&quot; rel=&quot;noreferrer&quot;&gt;An Introduction to the Geometry and Topology of Fluid Flows&lt;/a&gt; but applications of the material in the book to actual problems in meteorology may be few in so far as I am aware and others can perhaps provide better information. This workshop &lt;a href=&quot;http://mpe.dimacs.rutgers.edu/workshop/workshop-complex-analysis-and-geometry/&quot; rel=&quot;noreferrer&quot;&gt;Complex Analysis And Geometry&lt;/a&gt; does provide some applications of differential geometry to meteorology but these I reckon are most of the outlier groups and most of the work is on improving skill of NWP models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A colleague of mine in academia works on Potential Vorticity and &lt;a href=&quot;https://en.wikipedia.org/wiki/Slow_manifold&quot; rel=&quot;noreferrer&quot;&gt;Slow manifolds&lt;/a&gt; which is a part of &lt;a href=&quot;https://en.wikipedia.org/wiki/Stability_theory&quot; rel=&quot;noreferrer&quot;&gt;Stability theory&lt;/a&gt; and fast manifolds/&lt;a href=&quot;https://en.wikipedia.org/wiki/Inertial_manifold&quot; rel=&quot;noreferrer&quot;&gt;inertial manifolds&lt;/a&gt;. Essentially one is looking for a point after which the flow becomes unstable and why is that ? That is because unstable flows can be ultimately linked to weather forecasting and NWP models. There is the famous paper by Edward Lorenz that reviews that topic - &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/1520-0469%281992%29049%3C2449%3ATSMII%3E2.0.CO%3B2&quot; rel=&quot;noreferrer&quot;&gt;The slow manifold what is it ?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While it is numerical work I  and many others use &lt;a href=&quot;https://en.wikipedia.org/wiki/Vector_spherical_harmonics&quot; rel=&quot;noreferrer&quot;&gt;Vector Spherical Harmonics &lt;/a&gt; because we all deal with global circulation models(&lt;a href=&quot;https://en.wikipedia.org/wiki/Spectral_method&quot; rel=&quot;noreferrer&quot;&gt;spectral method&lt;/a&gt;) and others use &lt;a href=&quot;https://en.wikipedia.org/wiki/Wavelet&quot; rel=&quot;noreferrer&quot;&gt;wavelets&lt;/a&gt; to analyze &lt;a href=&quot;https://en.wikipedia.org/wiki/Equatorial_wave&quot; rel=&quot;noreferrer&quot;&gt;equatorial waves&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally there is this &lt;a href=&quot;http://climate-dynamics.org/wp-content/uploads/2015/08/gpv.pdf&quot; rel=&quot;noreferrer&quot;&gt;paper by Tapio Schneider&lt;/a&gt; that mentions &lt;a href=&quot;https://en.wikipedia.org/wiki/Gauge_theory&quot; rel=&quot;noreferrer&quot;&gt;Gauge transformations&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-07-07T04:47:59.367" LastActivityDate="2019-07-07T04:47:59.367" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17387" PostTypeId="1" CreationDate="2019-07-07T05:22:46.350" Score="3" ViewCount="52" Body="&lt;p&gt;Jetstreams move at an altitude of roughly 6-9km above the sea level. Since, it is moving at such a great altitude how could it have possible impacts on the land? And how will jetstreams that flow at such a high altitude cause heat waves in regions below it?&lt;/p&gt;&#xA;" OwnerUserId="17178" LastActivityDate="2019-07-07T05:22:46.350" Title="How does jetstreams lead to formation of heat waves in Europe?" Tags="|climate|geography|jet-stream|" AnswerCount="0" CommentCount="5" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17388" PostTypeId="1" AcceptedAnswerId="17389" CreationDate="2019-07-07T10:27:36.947" Score="1" ViewCount="53" Body="&lt;p&gt;&lt;a href=&quot;https://www.nasa.gov/feature/jpl/curiosity-detects-unusually-high-methane-levels&quot; rel=&quot;nofollow noreferrer&quot;&gt;Past week, NASA announced Curiosity Rover measured 21 ppbv of &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CH_4}$&lt;/span&gt; on Mars.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This week, NASA's Curiosity Mars rover found a surprising result: the largest amount of methane ever measured during the mission — about 21 parts per billion units by volume (ppbv).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, apparently, Mars atmosphere is methane free. ESA satellites are not measuring it:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;We did not detect any methane over a range of latitudes in both hemispheres, obtaining an upper limit for methane of about 0.05 parts per billion by volume, which is 10 to 100 times lower than previously reported positive detections&quot; (Korablev et al.,2019).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What is the possible and probable source of the methane Rover is measuring?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/s41586-019-1096-4&quot; rel=&quot;nofollow noreferrer&quot;&gt;-&lt;strong&gt;Korablev, O. et al. (2019)&lt;/strong&gt;:&quot;No detection of methane on Mars from early ExoMars Trace Gas Orbiter observations.&quot; &lt;em&gt;Nature&lt;/em&gt; &lt;strong&gt;568&lt;/strong&gt;, pages 517–520&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-07-07T10:51:22.573" LastActivityDate="2019-07-07T17:16:38.833" Title="Possible and probable source of Curiosity Rover's $\small\sf{CH_4}$ detection on Mars" Tags="|geochemistry|planetary-science|mars|methane|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17389" PostTypeId="2" ParentId="17388" CreationDate="2019-07-07T13:19:51.863" Score="3" Body="&lt;p&gt;The possible source of methane is biological, and that is what everyone is hoping for, but the more likely source is geological, produced by chemical reactions between rock and water deep underground and issuing though fissures to the surface. We are dealing with very small amounts here which are difficult to detect and measure with precision. Once out in the open, they are dispersed by breezes and decomposed by sunlight, so that could explain why they come and go. It has been suggested that methane abundance varies with the seasons, but I can't see any mechanism for that, apart from clathrates. Clathrates are a sort of ice composed of water and methane, and are abundant on Earth in the ocean and in Arctic tundra. When heated, clathrates decompose and release methane. Another suggestion is that the Curiosity rover is incontinently leaking methane wherever it goes and contaminating the samples it analyses, but I cant see any explanation for that either. I think methane has been detected on Mars, but we will have to keep an open mind on the source until more data has been gathered. My own opinion is that there has never been life on Mars, but I agree that we can't rule out the possibility that 4 billion years ago conditions were sufficiently Earth-like that Mars evolved its own primeval soup and life got started in the same way as it did on Earth, but has since been eradicated or driven underground.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-07-07T17:16:38.833" LastActivityDate="2019-07-07T17:16:38.833" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17390" PostTypeId="2" ParentId="17381" CreationDate="2019-07-07T16:50:41.840" Score="2" Body="&lt;p&gt;There are several contributing factors, &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;livestock, Livestock is easy animals produce co2 but their methane is a bigger problem, methane is a better greenhouse gas than the co2 that the feed plants took in.   Livestock waste is also a problem , people do not realize how much waste modern factory farms produce, specially when stored as a liquid is it produces all the problems of rice production with addition release of methane from the waste itself. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;transportation, transportation of ag products to market are almost all petroleum based. Depending on the source this may or may not be included in agricultural emissions.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Landuse, changing land, especially things like draining wetlands and burning forest for farmland are big contributors, Wetlands in particular produce huge amounts of co2 and keep doing so for decades if not centuries, all the organics built up in wetland start oxidizing when drained, this is basically the same as burning petroleum without actually getting any usable energy out of it. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.ars.usda.gov/news-events/news/research-news/2014/a-closer-look-at-links-between-fertilizers-and-greenhouse-gas-emissions/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fertilizer&lt;/a&gt; produces a &lt;a href=&quot;https://www.sciencenews.org/article/fertilizer-produces-far-more-greenhouse-gas-expected&quot; rel=&quot;nofollow noreferrer&quot;&gt;plethora of problems&lt;/a&gt;, and could justify an question all its own. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Rice, rice production has been called out as particularly problematic.  You would think this would produce the opposite effect to draining wetland but it is actually worse. Bacteria in flooded soil produces methane instead of co2 and as I said methane is better greenhouse gas, too top it off rice fields are supplied with enough nutrients to keep the bacteria producing way above normal wetland levels and keep it from being trapped the way carbon in mostly anaerobic wetlands will be. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions#agriculture&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2019-07-08T03:11:01.577" LastActivityDate="2019-07-08T03:11:01.577" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17396" PostTypeId="2" ParentId="17378" CreationDate="2019-07-08T09:59:17.533" Score="3" Body="&lt;p&gt;You can download seismic data in csv format &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/feed/v1.0/csv.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;at USGS&lt;/a&gt;, from past hour, past day, past week and past month.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you wish to download ancient data you need to use the &lt;a href=&quot;https://earthquake.usgs.gov/fdsnws/event/1/&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS API&lt;/a&gt;. There is a query option: format=csv.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is an example of an URL that gives you seismic data in csv format from 2014-01-01 to 2014-01-02:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthquake.usgs.gov/fdsnws/event/1/query?format=csv&amp;amp;starttime=2014-01-01&amp;amp;endtime=2014-01-02&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earthquake.usgs.gov/fdsnws/event/1/query?format=csv&amp;amp;starttime=2014-01-01&amp;amp;endtime=2014-01-02&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/14372/catalog-of-all-significant-earthquakes-since-1900/14373?r=SearchResults#14373&quot;&gt;User Kristjan shared a Python script to ask the API for all available data since 1900&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-08-10T11:55:20.890" LastActivityDate="2019-08-10T11:55:20.890" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17397" PostTypeId="2" ParentId="12483" CreationDate="2019-07-08T11:32:04.960" Score="-1" Body="&lt;p&gt;Stromatolite structure. The graininess a beat up or weathered limestone of some sort. &lt;/p&gt;&#xA;" OwnerUserId="17314" LastActivityDate="2019-07-08T11:32:04.960" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17398" PostTypeId="2" ParentId="12483" CreationDate="2019-07-08T11:55:41.467" Score="0" Body="&lt;p&gt;Stromatolite structure. The graininess a beat up or weathered limestone of some sort. But if it scratches glass it may be dolomatized limestone with some silica grains, enough to scratch glass. Stromatolite is often of chert but I haven't seen chert weathered like this. The layering looks like chert too. It's a puzzle. &lt;/p&gt;&#xA;" OwnerUserId="17315" LastActivityDate="2019-07-08T11:55:41.467" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17399" PostTypeId="2" ParentId="8115" CreationDate="2019-07-08T12:47:30.590" Score="1" Body="&lt;p&gt;There are two ways in which waves can sort particles on a beach, and both depend on surface area to weight ratio. The larger, toe-sized particles you describe have less surface area to volume (weight) ratio than the sand-sized particles, so were first to drop out of the water flow. The lighter particles had more surface area per unit of weight for the waves to act on, so were slower to drop out and were carried further up the beach. Why the lowest level sand grains were precipitated in deeper water, before the toe-sized particles, is less easy to understand, but one possible reason is that they contained some heavy mineral such as tin, which altered the surface area to weight ratio and caused them to drop out first. This principle is well seen in gold panning machines, where the heavy gold particles drop out of the flowing water first,while the lighter particles are carried further on, even when they are larger than the flecks of gold.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-08T12:47:30.590" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17400" PostTypeId="2" ParentId="13644" CreationDate="2019-07-08T13:22:02.020" Score="0" Body="&lt;p&gt;The Deccan Traps super-eruption 66 million years ago dwarfed even the Toba eruption of 75 thousand years ago and, perhaps assisted by the Chicxulub impact, had a very damaging effect on marine life, where extinctions were just as high as on land. I doubt whether the beneficial aspects of a really large eruption, such as adding vital nutrients to the surface waters of the ocean, would outweigh the deleterious effects such as global cooling. There are a few super-volcanoes around the world waiting to erupt, one of them in Yellowstone National Park, but none are expected to erupt in the next few thousand years, and when Yellowstone does eventually blow it is highly unlikely to be as severe as the Deccan Traps eruptions and probably not as bad as Toba.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-08T13:22:02.020" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17401" PostTypeId="2" ParentId="8115" CreationDate="2019-07-08T15:53:49.250" Score="1" Body="&lt;p&gt;After looking at the photo of the region I would say there are a couple of processes involved.  First this being a lake the most energetic water level would be at the wave zones.  Essentially the boat wakes and wind waves all strike the shore in a relatively narrow band.  This would uplift and allow the fines, sand, to be transported either upwards on the shore, soft sand region, or down lower into the firm sand zone.  Once in the water there is another sorting process.  The wave action on the shore also generates another erosional force and that would be the longshore current.  The water washing onto the beach generates a current that flows along the beach.  This current is where the ripples are and what you are seeing is sand being moved along this zone.  Finally, there are human factors.  The beach outlined is surrounded by groins, these are barriers placed into the water perpendicular to the beach to prevent the sand being washed away by the longshore current, see &lt;a href=&quot;https://www.nap.edu/read/11764/chapter/5#59&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nap.edu/read/11764/chapter/5#59&lt;/a&gt;.  Finally being that the beach is a near a major metropolitan area it is very possible that the beach also gets sand added to it from time to time by the municipality.  Overall, you have the waves and the longshore current moving sand out of the wave zone and transporting it along the shore but you also have groins and possible human sand transport keeping some sand in place at the beach.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2019-07-08T15:53:49.250" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17402" PostTypeId="2" ParentId="17366" CreationDate="2019-07-08T22:11:18.917" Score="1" Body="&lt;p&gt;Somebody posted that rain is either formed via collision-coalescence or the Bergeron-Findelsen process. This is misleading. The simplest classification of rain processes is into &quot;warm-rain&quot; and &quot;cold rain&quot; processes, where the former involves creation of rain by vapor and liquid phases, and the latter involves creation of rain by vapor, liquid, and solid phases of water. In the former, rain drops can form via &quot;autoconversion&quot; (vapor deposition onto liquid drops until they reach the size classified as rain), or collision-coalescence. In cold rain processes, rain can also be formed by melting ice particles, typically as they descend below the environmental 0 degree C level. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Bergeron-Findelsen process is a process by which ice particles grow via vapor deposition in the presence of supercooled liquid water. Because of a difference in saturation vapor pressure over ice vs. over water, in these conditions ice will grow via vapor deposition at the expense of the water droplets, which decrease in size via evaporation. Ice particles can also grow via other processes such as aggregation (ice particles sticking to other ice particles), riming (liquid drops sticking to ice particles), or plain-old vapor deposition (i.e. not in the presence of supercooled liquid droplets). Ice particles (e.g. snow, hail, graupel) grown via any of these processes can then sediment and melt, becoming rain. While the Bergeron-Findelsen process is an important cold rain process, it is not the only one, and primarily acts to grow ice (that might later melt to become rain). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this helps. &lt;/p&gt;&#xA;" OwnerUserId="7429" LastActivityDate="2019-07-08T22:11:18.917" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17403" PostTypeId="2" ParentId="12028" CreationDate="2019-07-08T22:28:44.217" Score="1" Body="&lt;p&gt;First off, as others have pointed out, &quot;Doppler&quot; refers to the ability to determine the velocity of stuff (rain, snow, etc) towards/away from the radar. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Radar data are often assimilated to produce better numerical weather forecasts (i.e. using computer weather models). Typically the &quot;main&quot; variable of interest for this is the Doppler radial velocity (the velocity at which the rain/cloud/snow is moving towards/away from the radar) and NOT the radar reflectivity (which is related to the size/concentration of the rain/cloud/snow particles). Usually what you'll see on a TV weather station's radar display is something related to the reflectivity. The reasons why numerical weather forecast data assimilation mostly uses radial velocity are perhaps too complicated to get into here, but in short, the radial velocity provides information to the numerical weather model that's less complicated for the  model to &quot;use&quot; than the reflectivity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Doppler radial velocity from a radar is an essential tool for determining if a thunderstorm is rotating, and whether it might produce a tornado, or other damaging winds. Google terms like &quot;tornado vortex signature&quot; or &quot;tornado velocity couplet&quot; to see what this looks like. Generally for tornadoes the radar will show air moving towards the radar in close proximity to air moving away from the radar, indicating rotation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Doppler radars are also used for more sophisticated research into cloud physics. For example, by pointing a radar vertically and observing the velocity at which rain/snow/hail falls, insight can be gained into the composition of these particles and the processes that grow them. &lt;/p&gt;&#xA;" OwnerUserId="7429" LastActivityDate="2019-07-08T22:28:44.217" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17405" PostTypeId="1" CreationDate="2019-07-09T01:33:15.080" Score="1" ViewCount="363" Body="&lt;p&gt;&lt;a href=&quot;http://www.purdue.edu/newsroom/research/2010/100830FischbachJenkinsDec.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.purdue.edu/newsroom/research/2010/100830FischbachJenkinsDec.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The link above talks about a research paper from Purdue University that the researchers had detected slight fluctuations in radioactive isotope decay rates and  might affect how we uses radiometric dating. Young Earth creationists did used this to claim that radiometric dating is not accurate and that it is base on assumptions. &lt;a href=&quot;https://www.discovercreation.org/blog/2012/10/26/80-years-of-scientific-fact-wrong-radioactive-decay-rates-not-constant/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.discovercreation.org/blog/2012/10/26/80-years-of-scientific-fact-wrong-radioactive-decay-rates-not-constant/&lt;/a&gt; Could the rate of radioactive decay be different in the past that today?&lt;/p&gt;&#xA;" OwnerUserId="7210" LastActivityDate="2019-07-10T12:23:51.893" Title="How do we know the rate of decay for radiometric dating is constant?" Tags="|dating|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17406" PostTypeId="2" ParentId="17366" CreationDate="2019-07-09T03:31:30.740" Score="1" Body="&lt;p&gt;&lt;strong&gt;Dew&lt;/strong&gt; refers to direct condensation of water vapor to water &lt;em&gt;without hygroscopic nuclei&lt;/em&gt; on surface objects. It's caused by condensation of moist air caused by &lt;em&gt;radiation and contact cooling&lt;/em&gt; of moist air lying over it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, &lt;em&gt;hygroscopic nuclei&lt;/em&gt; play an important role in case of rainfall as they play a crucial role in the formation of cloud droplets. For rainfall, the moist air must ascend, saturate and condense. &lt;em&gt;Adiabatic cooling&lt;/em&gt; due to an &lt;em&gt;upward movement of air&lt;/em&gt; is one of the most important mechanisms of condensation and related precipitation including rainfall.&lt;/p&gt;&#xA;" OwnerUserId="17178" LastActivityDate="2019-07-09T03:31:30.740" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17407" PostTypeId="1" CreationDate="2019-07-09T06:38:21.777" Score="2" ViewCount="817" Body="&lt;p&gt;I have taken a thunderstorm case where I need to calculate indices but I am not getting any code related stability indices in Python language, the code is available in GRADS, NCL for me it's difficult to understand. I used MetPy code but they are not calculated LI, KI, and other indices...Thanks in advance &#xA;Below code is wrong that I know I used the formula but tell me the correct way.    &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;nc1=Dataset('pl_120415.nc')&#xA;lat1=np.array(nc1.variables['latitude'])&#xA;lon1= np.array(nc1.variables['longitude'])&#xA;lev= np.array(nc1.variables['level'])&#xA;time= nc1.variables['time']&#xA;r= nc1.variables['r'][:,:,25:28,20:25]&#xA;t= nc1.variables['t']&#xA;u= nc1.variables['u'][:,:,25:28,20:25]&#xA;v= nc1.variables['v'][:]&#xA;w= nc1.variables['w']&#xA;&#xA;t_500= nc1.variables['t'][:,21,:,:] ### domain Air Temperture  at 500 Pressure_level&#xA;tp_500= nc1.variables['t'][:,21,25:28,20:25] ## at specfific location temperature (parcel temperture)&#xA;&#xA;li=np.subtract(t_500,tp_500,dtype=np.float32)&#xA;&#xA;print(&quot;LI&quot;,li)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="15474" LastActivityDate="2021-03-31T13:10:05.590" Title="How to calculate Lifted Index from ERA5 pressure level data?" Tags="|era|python|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17408" PostTypeId="2" ParentId="17405" CreationDate="2019-07-09T09:08:34.307" Score="4" Body="&lt;p&gt;First of all, you shouldn't take creationists seriously; like flat earthists, their views are totally out of touch with reality. Rates of radioactive decay have been tested many times in the laboratory and found to be accurate. However, there have been some instances where a substantial change of temperature or the formation of a chemical compound involving the radioactive isotope produces a small change in the rate of decay. When used for radiometric dating, this is not a source of error. The main source of error is the minuteness of the samples that labs have to work with. For example, only one potassium atom in 100 is potassium 40,the half life of which is I,300,000,000 years. In argon potassium dating the volcanic tuffs the lab has to analyse contain only a tiny amount of potassium 40,and only 11 percent of that decays to form argon 40 (the remainder forms calcium 40). The lab has to detect and measure the tiny trace of argon which has formed in the sample since it was emitted by a volcano a few million years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sometimes several dating methods are used on the same fossil or artefact, and if they are in rough agreement the dating is reliable. If you are looking for pin point accuracy, you won't get it with radiometric dating, but if accuracy to within a few percent is good enough, then that is usually achievable. The colossal orders-of-magnitude errors which creationists try to convince you of never happen.       &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-09T09:08:34.307" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17409" PostTypeId="1" AcceptedAnswerId="17410" CreationDate="2019-07-09T09:33:45.577" Score="2" ViewCount="644" Body="&lt;p&gt;Earth rocks are frequently &lt;a href=&quot;https://en.wikipedia.org/wiki/Fold_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;folded&lt;/a&gt; at surface.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/un1Ke.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/un1Ke.jpg&quot; alt=&quot;Rocks folded at Crete, Greece&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;em&gt;Folds in alternating layers of limestone and chert in Crete, Greece.&lt;/em&gt; &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/w/index.php?curid=593286&quot; rel=&quot;nofollow noreferrer&quot;&gt;commons.wikimedia&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Are earthquakes the main mechanism producing the folds?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If so, have ever geologists observed the development of a fold after an earthquake?&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-07-09T10:34:49.577" LastActivityDate="2019-07-09T10:47:02.977" Title="Do earthquakes produce folds on rocks?" Tags="|geology|earthquakes|earth-history|tectonics|structural-geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17410" PostTypeId="2" ParentId="17409" CreationDate="2019-07-09T10:47:02.977" Score="3" Body="&lt;p&gt;No, earthquakes are sudden, often very energetic events which produce faults and discontinuities. There is a sharp break in the strata when subjected to a powerful earthquake. The folding of strata is a much more gradual process, where rock deep underground is subjected to enormous lateral pressure over millions of years. This pressure is caused by plate movements (continental drift). Earthquakes have a variety of causes, but the most violent ones are also caused by continental drift as one plate slides past another along a fault line. The San Andreas Fault in California is an example of this. One of the plates is moving, but friction holds it in place for a while, sometimes for many years. Pressure builds up until suddenly the friction force holding it in place gives way, and there is an earthquake as the moving plate slips forward for a few metres. For these reasons, geologists have never seen a newly created fold after an earthquake. It is impossible for one to form in so short a time.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-09T10:47:02.977" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17411" PostTypeId="1" AcceptedAnswerId="17415" CreationDate="2019-07-09T13:46:50.433" Score="15" ViewCount="3493" Body="&lt;p&gt;North-hemisphere ice-shelf melts on summer and grows on winter. I would expect appreciable changes on sea-level between seasons, but sea-level looks equal on winter than on summer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why doesn't sea level show seasonality?&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-07-10T08:41:50.297" LastActivityDate="2019-07-12T14:35:02.073" Title="Why doesn't sea level show seasonality?" Tags="|oceanography|glaciology|sea-level|ice-shelf|" AnswerCount="2" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="17412" PostTypeId="1" CreationDate="2019-07-09T14:22:56.047" Score="2" ViewCount="101" Body="&lt;p&gt;This IRIS &lt;a href=&quot;https://twitter.com/IRIS_EPO/status/1146950304262475776&quot; rel=&quot;nofollow noreferrer&quot;&gt;tweet&lt;/a&gt; shows a video of siesmic waves from the recent M6.4 Earthquake in California rolling across the US.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've made a small GIF to give the idea but the &quot;GIF&quot; in the tweet shows the whole thing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the bottom there is a plot of something versus time, the x-axis extends for about &lt;em&gt;35 minutes!&lt;/em&gt;, and the vertical scale bar on the right is 44 nanometers(?) tall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What does this 1D plot of displacement(?) versus time actually show? Is it a calculated quantity or a direct measurement of something? What are the vertical blue lines labeled P, PcP and Sc5?&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Watch the waves from the M6.4 southern California #earthquake roll across the USArray seismic network (&lt;a href=&quot;http://www.usarray.org&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.usarray.org&lt;/a&gt; )! #socalearthquake THREAD&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Low quality GIF, please see the &lt;a href=&quot;https://twitter.com/IRIS_EPO/status/1146950304262475776&quot; rel=&quot;nofollow noreferrer&quot;&gt;tweeted original&lt;/a&gt;!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/4ozid.gif&quot; alt=&quot;IRIS M6.4 California Earthquake &amp;quot;GIF&amp;quot; tweet&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2019-07-09T14:43:55.797" LastActivityDate="2019-07-11T16:45:17.623" Title="What is the vertical axis of this waveform shown in this tweeted IRIS GIF?" Tags="|earthquakes|seismic|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17414" PostTypeId="2" ParentId="17411" CreationDate="2019-07-09T15:56:51.273" Score="2" Body="&lt;p&gt;In the Arctic there is mostly floating sea ice and the mass of this does not change the sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When snow falls on the floating sea ice the weight of the snow is the same as the weight of the sea water it displaces so there will not be any change in sea level from this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the snow falling on land during winter is water temporary removed from the sea, so the sea level will drop a little during winter. &lt;a href=&quot;https://research.csiro.au/slrwavescoast/sea-level/sea-level-change/&quot; rel=&quot;nofollow noreferrer&quot;&gt;See seasonal changes in sea level&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the Antactic winter, the sea level drop will be less as most of the snow will fall on the floating ice and on a narrow band of land ice around Antarctica. This is mainly due to the circumpolar wind around Antarcica where less moist air will blow into the interior of Antarctica.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The tiny bit of snow falling in the central part of Antarctica is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Diamond_dust&quot; rel=&quot;nofollow noreferrer&quot;&gt;diamond dust&lt;/a&gt;, this is tiny flat ice crystalls; they will &lt;a href=&quot;https://en.wikipedia.org/wiki/Sublimation_(phase_transition)&quot; rel=&quot;nofollow noreferrer&quot;&gt;sublimate&lt;/a&gt; before or soon after they reach the ground due to the dry air and low temperature. &lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorDisplayName="user12525" LastEditDate="2019-07-10T09:58:16.807" LastActivityDate="2019-07-10T09:58:16.807" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17415" PostTypeId="2" ParentId="17411" CreationDate="2019-07-09T17:15:48.270" Score="25" Body="&lt;p&gt;Sea level has a strong seasonal signal. The annual variability is less than the daily changes associated with tidal forcing in most locations, but still can be on the order of 5-10 cm (maximum values about 15 cm). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The causes of the seasonal fluctuations are mostly associated with seasonal changes in wind intensity and patterns, changes in temperature that relate to &lt;a href=&quot;https://sealevel.nasa.gov/understanding-sea-level/global-sea-level/thermal-expansion&quot; rel=&quot;noreferrer&quot;&gt;thermal expansion&lt;/a&gt;, and in salinity (haline contraction) and river discharge fluctuations. The annual sea level cycle is only partially related to ice melt and this effect tends to be quite local. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The largest sea level seasonal cycles are associated with areas in the vicinity of large rivers with strong seasonal cycles (e.g., Bay of Bengal). Also, there is a lot of spatial variability in the seasonal cycle with the northern hemisphere having a larger signal (likely caused by the stronger seasonality in wind patterns).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An example of the seasonal cycle can be seen in the monthly data from the Permanent Service for Mean Sea Level (PSMSL) for Woods Hole, MA (USA) (in m offset to avoid negative values in the PSMSL database). The monthly data shows strong seasonal variability and also a clear trend. As the data is monthly averaged, the tidal oscillations are filtered out. Most sea level rise graphs tend to use annual data and thus the seasonal information is not included.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DG8lR.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DG8lR.png&quot; alt=&quot;Woods Hole water level PSML&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2019-07-12T14:35:02.073" LastActivityDate="2019-07-12T14:35:02.073" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17416" PostTypeId="1" CreationDate="2019-07-09T19:20:44.253" Score="1" ViewCount="228" Body="&lt;p&gt;An analogy I came up with is:&#xA;Predicting earthquake strength and timing is like throwing a sheet of glass on the ground and predicting how many pieces it will break to and where they'll end up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this a good analogy?&#xA;I have no geology background or anything similar -- I'm just a person that wants to understand why it's hard. I KNOW it's hard, but why?&lt;/p&gt;&#xA;" OwnerUserId="17326" LastActivityDate="2019-07-10T10:06:03.307" Title="Why is it hard to predict earthquakes?" Tags="|earthquakes|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17417" PostTypeId="2" ParentId="11959" CreationDate="2019-07-09T20:57:29.157" Score="2" Body="&lt;p&gt;SOI operates Falkor, which also broadcasts live video. They stream via youtube, currently, as does OET.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://schmidtocean.org/technology/live-from-rv-falkor/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://schmidtocean.org/technology/live-from-rv-falkor/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Occasionally other operations, such as Woods Hole, will operate telepresence cruises, but these three are consistent operators in the space as they have dedicated ROVs and satellite equipment/contracts for their ships. They co-publish an annual supplement to The Oceanography Society's spring issue:  &lt;a href=&quot;https://tos.org/oceanography/issue/volume-32-issue-01-supplement&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://tos.org/oceanography/issue/volume-32-issue-01-supplement&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;-Ethan (formerly with OET)&lt;/p&gt;&#xA;" OwnerUserId="17328" LastEditorUserId="7314" LastEditDate="2019-07-10T00:43:20.847" LastActivityDate="2019-07-10T00:43:20.847" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17418" PostTypeId="2" ParentId="17416" CreationDate="2019-07-09T21:47:14.060" Score="2" Body="&lt;p&gt;The easiest way I can explain it is you haven thousands of different material joined in billions of ways with chunks of all different sizes, there are just too many varables for an accurate prediction. becuase earthquakes are caused by a slow build up of pressure it is impossible to predict exactly when it will break because the forces are not spread evenly and the material properties of the rock are not consistent.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;look at material testing, if you have a uniform object under steady predictable force they can predict when it will break with some reliability usually within a few seconds. but across a geologic timescale that kind of accuracy would give you plus or minus thousands of years, and that is under perfect conditions, Add in the complexity of the plates make up and you get even more error. Worse with plates the force on them is not uniform there are several forces acting on it and they are not spread evenly.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;to use your glass analogy, imagine a sheet of glass several yards in diameter, but this glass was poorly made its lumpy so the thickness varies by several inches and is full of bubble and impurities. now try to predict when it will break based on a a group of children randomly throwing pennies onto it. You know it will break eventually but predicting when and where is functionally impossible. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2019-07-09T21:47:14.060" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17420" PostTypeId="2" ParentId="9355" CreationDate="2019-07-10T01:50:32.527" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Ambient or roadside concentrations for each pollutant, over different&#xA;  averaging times, will be converted into an index value. &lt;strong&gt;In general,&#xA;  there are &lt;a href=&quot;https://docsbay.net/a-study-of-the-air-pollution-index-reporting-system&quot; rel=&quot;nofollow noreferrer&quot;&gt;three common methods&lt;/a&gt; to achieve this.&lt;/strong&gt; The most popular&#xA;  approach is often called the &lt;strong&gt;US-based system&lt;/strong&gt;. Pollutant&#xA;  concentrations for each pollutant are transformed onto a normalised&#xA;  numerical scale of 0 to 500, with an index value of 100 corresponding&#xA;  to the primary National Ambient Air Quality Standard (NAAQS) for each&#xA;  pollutant (USEPA, 2006, website 14). Places like Singapore, China,&#xA;  Thailand, Malaysia, South Korea, Taiwan, Hong Kong, and Macau designed&#xA;  their AQI /API systems based on the US model. The key reference point&#xA;  of these systems would be the index value of 100, which is based on&#xA;  the short-term air quality standards of the respective jurisdictions.&#xA;  Very often, the index value of 50 is anchored to the long-term air&#xA;  quality standards.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;A similar approach is being used in Australia, whereby &lt;strong&gt;pollutant&#xA;  concentrations are also being transformed onto a scale.&lt;/strong&gt; There,&#xA;  however, a linear or proportional scale is used instead of a&#xA;  normalised scale (i.e. a scale which takes the variation into&#xA;  account), and the index is then calculated in direct proportion to the&#xA;  air quality standards or environmental goals (Ove Arup, 2007, 1).&#xA;  Moreover, the scale used in New South Wales is different from the one&#xA;  used in Queensland, Victoria, and Adelaide (in South Australia). In&#xA;  New South Wales, an index value of 50 means that the pollutant&#xA;  concentration is equal to the standard level. For the other states and&#xA;  cities, the index value of 100 carries the same meaning (Ove Arup,&#xA;  2007, 1; website 4).&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The third approach is the &lt;strong&gt;banding system&lt;/strong&gt;, which is more popular in&#xA;  European countries like the UK and France (websites 3, 13). The main&#xA;  deviation is that instead of using an index scale of 0 to 500, a scale&#xA;  of 0 to 10 is being used. For the UK system, this index scale of 10 is&#xA;  further broken down into four bands of ‘low’ (1-3), ‘moderate’ (4-6),&#xA;  ‘high’ (7-9) and ‘very high’ (10) (website 13). The key reference&#xA;  point for this banding system is the breakpoint value between the&#xA;  ‘low’ and ‘moderate’ bands. The lower bound of index value 4 is set to&#xA;  correspond to the UK Air Quality Standards for all pollutants but NO 3&#xA;  2. In this case, the 1-hour national standard for NO2 is 200 g/m , whereas the lower bound of index value 4 for NO2 is 287 g/m3 (website&#xA;  13).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://docsbay.net/a-study-of-the-air-pollution-index-reporting-system&quot; rel=&quot;nofollow noreferrer&quot;&gt;A Study of the Air Pollution Index Reporting System&lt;/a&gt; by &lt;em&gt;Prof. Wong Tze Wai&lt;/em&gt;&#xA;School of Public Health and Primary Care The Chinese University of Hong Kong &lt;/p&gt;&#xA;" OwnerUserId="17330" LastActivityDate="2019-07-10T01:50:32.527" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17424" PostTypeId="2" ParentId="17416" CreationDate="2019-07-10T10:06:03.307" Score="1" Body="&lt;p&gt;Earthquakes have al sorts of causes and all sorts of intensities, but your question probably refers to the most powerful and destructive ones. These are caused by the movement of tectonic plates involved in continental drift. A classic example is the San Andreas Fault in California. where one plate is moving past another, leaving a clearly visible rift for hundreds of miles. The western plate is gradually moving north, and grinding against the eastern plate. The movement stops for a while after energy has been released, but then the pressure builds up again as the western plate tries to continue its journey, but is held back by friction. The forecasting difficulty comes in predicting how long the friction forces can hold before they suddenly give way. It is safe to say that there will be another powerful earthquake somewhere along the San Andreas Fault in the next 50 years, as pressure is building up for another lurch forward, but as things stand it is impossible to predict exactly when or at which point along the fault this event will occur. The geologists who have the fault under surveillance could make a much better prediction than I could, but even they don't know exactly when the next friction point will give way, or exactly where along the fault it will be.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-10T10:06:03.307" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17427" PostTypeId="2" ParentId="17405" CreationDate="2019-07-10T12:13:16.557" Score="1" Body="&lt;p&gt;Firstly, there are simplified analytical cases that even &lt;a href=&quot;https://en.wikipedia.org/wiki/Gamow_factor&quot; rel=&quot;nofollow noreferrer&quot;&gt;undergrad students are able to master&lt;/a&gt; that inform us how decay rates generally depend on other natural constants and available energy levels.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Those cases, while not describing full reality, give us important information, namely that if a decay constant would not be constant, then either &lt;em&gt;other natural constants&lt;/em&gt; would also vary (which would be observed in many other experiments) or somehow the number of available decay energy levels changes based on &lt;em&gt;exterior conditions&lt;/em&gt;.&lt;br&gt;&#xA;The latter would mean, that effectively the only way a decay constant could change, is when it would depend on the atomic shell structure of the atom.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Well, it turns out that in some very special cases nuclear decay rates can be quite sensitive to their &lt;a href=&quot;https://en.wikipedia.org/wiki/Radioactive_decay#Changing_decay_rates&quot; rel=&quot;nofollow noreferrer&quot;&gt;ionization state&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To quote the wikipedia on this&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Rhenium-187 is another spectacular example. 187Re normally beta decays to 187Os with a half-life of 41.6 × &lt;span class=&quot;math-container&quot;&gt;$10^9$&lt;/span&gt; years,[27] but studies using fully ionised 187Re atoms (bare nuclei) have found that this can decrease to only 33 years. This is attributed to &quot;bound-state β− decay&quot; of the fully ionised atom – the electron is emitted into the &quot;K-shell&quot; (1s atomic orbital), which cannot occur for neutral atoms in which all low-lying bound states are occupied.[28] &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Those examples, while academically very interesting, do not impact the terrestrial radiometric dating methods because&lt;br&gt;&#xA;1.) the elements used for dating do not show this variability in laboratory experiments&lt;br&gt;&#xA;2.) no terrestrial extreme environment even existed where elements like 187Re could be fully ionized - the temperatures needed for that correspond to 100's of Million Kelvin!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What those creation websites do is say &quot;because one element has some obscure conditions under which its decay constant is not constant, therefore all decay constants for all elements must be in doubt! (also God did it)&quot;, which is an obvious generalization fallacy, and a massive insult to the scores of physicists working on those topics.&lt;br&gt;&#xA;The other insult to logic here that is happening is by cherrypicking the 176Lu-&gt;176Hf system and a temperature they like (and i'm quoting here from &lt;a href=&quot;https://creation.com/billion-fold-acceleration-of-radioactivity-demonstrated-in-laboratory&quot; rel=&quot;nofollow noreferrer&quot;&gt;cration.com, creationist journal&lt;/a&gt;) &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Thus, at 600 MK, the effective t½ of 176Lu is only about 8 days!11 This is short enough that if, as discussed earlier, all of the atoms in the universe had been created in a very hot state—which just means very high kinetic energies—(and maintained that way for several hours on the First Day), all the excess 176Hf in existence would have been generated within that short period.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;to argue for a seven-day creation scenario.&lt;br&gt;&#xA;To a layman this might seem convincing, hell, they even quote the reputable physics journals on those results! So the way they go is take actual science, and cherrypick from it until they find something that fits their narrative.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the 'uniformitarian geologist'(sic) worldview, we do consider all available elements, all decay routes, and if those converge onto one single message, then this must be the truth. That's why cherrypicking is as unscientific as it gets.&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="489" LastEditDate="2019-07-10T12:23:51.893" LastActivityDate="2019-07-10T12:23:51.893" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17428" PostTypeId="2" ParentId="17309" CreationDate="2019-07-10T19:12:44.750" Score="1" Body="&lt;p&gt;The CO&lt;sub&gt;2&lt;/sub&gt; is a greenhouse gas which causes a net heating effect as it retains additional solar radiation, the exact magnitude of this effect is still highly debated. The high altitude effects you've mentioned are often referred to as &quot;jet exhaust shading&quot; and it's estimated, based on some temperature data from the week after the 9/11 attacks in the US, that it causes roughly 4°C of cooling, this is because the jet exhaust contains water which condenses out as high &lt;a href=&quot;https://en.wikipedia.org/wiki/Albedo&quot; rel=&quot;nofollow noreferrer&quot;&gt;albedo&lt;/a&gt; clouds, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Stratospheric_sulfur_aerosols&quot; rel=&quot;nofollow noreferrer&quot;&gt;sulfur compounds that absorb solar radiation&lt;/a&gt; as well as the CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2019-07-10T19:12:44.750" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="17431" PostTypeId="1" CreationDate="2019-07-11T13:18:42.883" Score="4" ViewCount="619" Body="&lt;p&gt;I have a NetCDF file (gridded data) with a landsea mask. I would like to determine, for the coastal grid-cells, what the orientation of the coastline is. I need to do this in order to calculate the angle between incident wind direction and the coastline at each coastal grid cell. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, if at a certain location the coastline is zonal (east to west) and the land is to the south, and the sea to the north, the orientation would be 0°:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/crQnr.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/crQnr.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the coast is zonal but the position of land and ocean are inverted, the orientation of the coast would be 180°.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6EnOs.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6EnOs.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the coast is 45° with the land to the south, the angle is 45°. With the land to the north, the orientation is 135°... you get the idea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CeYHM.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CeYHM.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/dIRec.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dIRec.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any suggestions on how to get this information from the landsea mask grid?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you in advance. &lt;/p&gt;&#xA;" OwnerUserId="8396" LastEditorUserId="22648" LastEditDate="2021-06-08T18:09:29.330" LastActivityDate="2021-06-08T18:36:50.417" Title="How to determine the orientation of coastline from NetCDF file" Tags="|geomorphology|numerical-modelling|coastal|netcdf|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17432" PostTypeId="1" AcceptedAnswerId="17439" CreationDate="2019-07-11T14:43:15.770" Score="1" ViewCount="39" Body="&lt;p&gt;Does the &lt;a href=&quot;http://sepwww.stanford.edu/sep/prof/bei/sg/paper_html/node7.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;reciprocity principle&lt;/a&gt; hold true in an &lt;a href=&quot;https://wiki.seg.org/wiki/Seismic_anisotropy&quot; rel=&quot;nofollow noreferrer&quot;&gt;anisotropic&lt;/a&gt; subsurface environment?&lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2019-07-12T05:22:42.620" Title="Seismic wavefield theory: velocity anisotropy" Tags="|seismic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17433" PostTypeId="2" ParentId="17412" CreationDate="2019-07-11T16:45:17.623" Score="3" Body="&lt;p&gt;&lt;strong&gt;Answer 1&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The horizontal axis is indeed time (don't forget units and note how long those &lt;a href=&quot;http://geoscience.wisc.edu/~chuck/Classes/Mtn_and_Plates/eq_cycle.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;periods&lt;/a&gt; are!). As for the vertical axis, I'm certain that this is displaying vertical (or 'Z' or 'V') displacement. Keep in mind - like you mention - that we are only looking at a 1-D picure of the data, but there are other perspectives we are missing! For example, how is the earth being displaced with respect to North-South and/or East/West directions? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Answer 2&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The vertical blue line you reference indicates different seismic &lt;a href=&quot;https://www.ldeo.columbia.edu/res/pi/Monitoring/Doc/Srr_2006/GUIDE.PDF&quot; rel=&quot;nofollow noreferrer&quot;&gt;phases&lt;/a&gt; (or &lt;em&gt;arrivals&lt;/em&gt;). For example, you list 'P' and 'PcP' - but there are many others! For example 'SKS', 'SKKS', etc. - see the hyperlink to understand this notation and the seismic waveforms they correspond to.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;NOTE&lt;/strong&gt;(1): For the term &lt;em&gt;phase&lt;/em&gt; - be VERY careful with this word and the context I've applied it in. As is customary in geophysics, one word can refer to the same or different concepts. Read &lt;a href=&quot;https://library.seg.org/doi/abs/10.1190/1.1885500?journalCode=leedff&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; for a good follow-up example of what I'm describing in terms of &lt;em&gt;phase&lt;/em&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;NOTE&lt;/strong&gt;(2): Many seismograms like this will initially be displayed in the conventional NEV (or NEZ) or &lt;em&gt;North-East-Vertical&lt;/em&gt; coordinate system . But, to optimize many kinds of analyses and displays, one needs to rotate (or &lt;a href=&quot;https://en.wikipedia.org/wiki/Transformation_matrix&quot; rel=&quot;nofollow noreferrer&quot;&gt;transform&lt;/a&gt;) this system into another - &lt;a href=&quot;https://earthscience.stackexchange.com/questions/5007/how-are-the-zne-zrt-and-lqt-coordinate-systems-defined&quot;&gt;LQT&lt;/a&gt;. Read &lt;a href=&quot;https://service.iris.edu/irisws/rotation/docs/1/help/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; to understand what that means. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;NOTE&lt;/strong&gt;(3): How does one know or estimate seismic phases like these? You need an &lt;a href=&quot;http://ds.iris.edu/ds/products/emc-referencemodels/&quot; rel=&quot;nofollow noreferrer&quot;&gt;earth model&lt;/a&gt;! From the source location and at the instantaneous moment of when the seismic event occurs, a corresponding seismic wavefield is generated and travels throughout the earth - interacting with its fluid and/or elastic mediums - all the while responding to (or &lt;em&gt;&lt;a href=&quot;http://subsurfwiki.org/wiki/Convolutional_model&quot; rel=&quot;nofollow noreferrer&quot;&gt;convolving&lt;/a&gt;&lt;/em&gt;) its complex, 3-D velocity (and density) structure. As the seismic wavefield passes through different mediums via refraction, reflection, dispersion, &#xA;attenuation, etc., it changes and subsequent various phases are produced and then recorded at a station. The phases - i.g. 'SKS', 'P', and many others - basically tell a story of how/where the wavefield changed, which is great for analyzing the crust, all sections of the mantle, and even the core!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*I've included a lot here but you've asked an outstanding question that you (and I) can really learn from!&lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2019-07-11T16:45:17.623" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17434" PostTypeId="1" CreationDate="2019-07-11T16:54:58.017" Score="2" ViewCount="48" Body="&lt;p&gt;Recorded (or &lt;em&gt;raw&lt;/em&gt;) and processed pre/post-stack seismic data (relative amplitudes) usually display a standard normal distribution, albeit with a very small amount of skewness. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would be possible causes and/or significance if amplitudes did not retain a mean value of zero (or very nearly zero)?&lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2019-07-13T10:25:59.653" Title="Seismic amplitude distribution" Tags="|seismic|statistics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17435" PostTypeId="1" AcceptedAnswerId="17438" CreationDate="2019-07-11T19:46:20.390" Score="1" ViewCount="124" Body="&lt;p&gt;According to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Homo_floresiensis#Discovery&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia article&lt;/a&gt; on the species Homo floresiensis, the remains discovered in 2003 consist of &lt;em&gt;unfossilized&lt;/em&gt; bones. I would assume that means they are still composed of the original organic material left behind when the human specimen died thousands of years ago. Shoudn't that mean radiocarbon dating would be a good method to date the reamains? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many articles on Homo floresiensis also discuss how the remains were originally dated to ~12,000 years ago, but that this estimate was later revised to 60–100,000 years ago. However, everything I can find indicates that mostly geological dating methods were used, not radiometric dating.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why not? The Wikipedia entry on carbon dating says that it can only be used reliably to date specimens up to ~50,000 years, but could carbon dating then at least place a lower limit on the age of these remains? And why wouldn't it have been used back when they thought the specimens were only ~12,000 years old?&lt;/p&gt;&#xA;" OwnerUserId="17342" LastActivityDate="2019-07-12T04:45:14.907" Title="Can we carbon-date the remains of homo floresiensis found in 2003?" Tags="|dating|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17436" PostTypeId="2" ParentId="17435" CreationDate="2019-07-11T20:43:51.387" Score="1" Body="&lt;p&gt;If the fossils, or some of them, were as you describe them with no mineral replacement of the original material, then it would seem that C14 dating would be relevant for the youngest bones at least. If they had original material with adequate carbon in it,C14 is such an obvious method that they must have tried it, or had some very good reason not to. C14 is, like most methods, a tricky technique which doesn't always give accurate results. Perhaps the C14 date didn't tally with other methods they used, so they preferred not to mention it. 50,000 years is pushing the limits pf the C14 method and involves a small amount of the material being destroyed.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-11T20:43:51.387" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17438" PostTypeId="2" ParentId="17435" CreationDate="2019-07-12T04:45:14.907" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://www.sciencemag.org/news/2016/03/hobbit-was-separate-species-human-new-dating-reveals&quot; rel=&quot;nofollow noreferrer&quot;&gt;ScienceMag&lt;/a&gt; says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Rather than damaging the fossils by dating them directly, the team looked to the sediments in which they were found. They discovered pieces of charcoal in sediments at similar depths, and considered those to be proxies for the ages of the fossils themselves. The charcoal bits were dated to around 19,000 and 13,000 to 11,000 years before present.&lt;br&gt;&#xA;  But Liang Bau boasts a devilishly complicated geological history, as layers of silt and clay interleave with layers of weathered limestone, loose gravel, and volcanic ash. In many places, these layers have been scoured by erosion, altered by seeping water, and jumbled by tectonic activity.&lt;br&gt;&#xA;  ...&lt;br&gt;&#xA;  Dating on the gravelly sediment layer containing the fossils suggested it was deposited between 100,000 and 60,000 years ago; just above it is a layer of volcanic ash that was dated to about 60,000 years ago. This suggests that the fossils themselves couldn’t possibly be younger than 60,000 years old, the team reports online today in Nature.&lt;br&gt;&#xA;  To cap it off, the team has now directly dated the fossils themselves. Originally, researchers shied away from that analysis for fear of damaging them, Tocheri says. But this time, they felt they needed to do it. “It wasn’t until [we] were reasonably convinced that [the fossils] were probably older than 50,000 years old that we decided we needed to date them directly to be absolutely certain,” he says.&lt;br&gt;&#xA;  The team dated three arm bones found at different locations within the cave during previous excavations. Using uranium-thorium dating—which is based on the radioactive decay of uranium and thorium isotopes in a material—they found dates ranging from about 66,000 to 87,000 years old.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I could not find how the &quot;charcoal bits&quot; were dated, but it would be in the range for carbon dating.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-07-12T04:45:14.907" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17439" PostTypeId="2" ParentId="17432" CreationDate="2019-07-12T05:22:42.620" Score="2" Body="&lt;p&gt;Yes, or at least certainly in theory. If you look up any derivation of the &lt;em&gt;elastodynamic representation theorem&lt;/em&gt; you're bound to find that it holds for the most general version of the elastic wave equation:&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{align}\rho \frac{\partial^2 u_i(x,t)}{\partial t^2}&amp;amp; = \frac{\partial \sigma_{ij}}{\partial x_j} \\ \sigma_{ij}(x,t) &amp;amp; = c_{ijkl}(x)\varepsilon_{kl}(x,t)\end{align}&lt;/span&gt;&#xA;with &lt;span class=&quot;math-container&quot;&gt;$u$&lt;/span&gt; the displacement, &lt;span class=&quot;math-container&quot;&gt;$\sigma$&lt;/span&gt; the stress, &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; the density and &lt;span class=&quot;math-container&quot;&gt;$c_{ijkl}$&lt;/span&gt; Hooke's tensor. You'll have run into this tensor whenever you researched anisotropy, because it is how one describes anisotropy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main reference is a book by Aki &amp;amp; Richards (1982): &lt;a href=&quot;https://www.ldeo.columbia.edu/~richards/Aki_Richards.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ldeo.columbia.edu/~richards/Aki_Richards.html&lt;/a&gt; , but it is also derived in these handouts, see the bottom of page 15: &lt;a href=&quot;http://www.geo.uu.nl/~paulssen/Theoreticalseismology/handout.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.geo.uu.nl/~paulssen/Theoreticalseismology/handout.pdf&lt;/a&gt; . &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The notation &lt;span class=&quot;math-container&quot;&gt;$G_{nm}(\xi_2,\tau|\xi_1,t)= G_{mn}(\xi_1,\tau|\xi_2,t)$&lt;/span&gt; is the reciprocity relation. &lt;span class=&quot;math-container&quot;&gt;$G_{nm}(\xi_2,\tau|\xi_1,t)$&lt;/span&gt; is the measured displacement due to a point source in direction &lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt; at time &lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt; at location &lt;span class=&quot;math-container&quot;&gt;$\xi_1$&lt;/span&gt; as measured at time &lt;span class=&quot;math-container&quot;&gt;$\tau$&lt;/span&gt; at &lt;span class=&quot;math-container&quot;&gt;$\xi_2$&lt;/span&gt; in direction &lt;span class=&quot;math-container&quot;&gt;$n$&lt;/span&gt;. The reciprocity relation says that this recorded signal is identical to an experiment where a source in direction &lt;span class=&quot;math-container&quot;&gt;$n$&lt;/span&gt; at time &lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt; at location &lt;span class=&quot;math-container&quot;&gt;$\xi_2$&lt;/span&gt; is measured at time &lt;span class=&quot;math-container&quot;&gt;$\tau$&lt;/span&gt; at &lt;span class=&quot;math-container&quot;&gt;$\xi_1$&lt;/span&gt; in direction &lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt;. Hence, you can interchange source and receiver when you interchange source and receiver dirctions too.&lt;/p&gt;&#xA;" OwnerUserId="12155" LastActivityDate="2019-07-12T05:22:42.620" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17441" PostTypeId="1" CreationDate="2019-07-12T09:47:45.360" Score="1" ViewCount="43" Body="&lt;p&gt;I am a little confused by the terms &quot;regional&quot; and &quot;relative&quot; in the sea level change context. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Do the two words have the same meaning? Does the &quot;regional MSL trend&quot; in &lt;a href=&quot;https://www.aviso.altimetry.fr/index.php?id=1599&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.aviso.altimetry.fr/index.php?id=1599&lt;/a&gt; have the same meaning with relative sea level in &lt;a href=&quot;https://tidesandcurrents.noaa.gov/sltrends/sltrends.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://tidesandcurrents.noaa.gov/sltrends/sltrends.html&lt;/a&gt;?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Can we measure Relative Sea Level (RSL) with altimetry satellite data? &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="17346" LastEditorUserId="17346" LastEditDate="2019-07-12T10:11:07.577" LastActivityDate="2019-07-12T11:32:41.927" Title="Regional and Relative Sea level" Tags="|climate|oceanography|sea-level|remote-sensing|ocean-models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17442" PostTypeId="2" ParentId="17441" CreationDate="2019-07-12T11:32:41.927" Score="1" Body="&lt;p&gt;Assessing sea levels is a complicated business, as there are a number of factors which can affect sea level relative to a fixed point on land. For a start, land levels rise and fall; in some places land is lifted up by plate movements or volcanism, in other places  it may fall. Rising and falling atmospheric pressure makes very temporary local changes. The factor which causes the most concern these days is the rise in mean sea level caused by melting ice on land increasing the amount of water in the ocean. This has been going on since the end of the last ice age some 12,000 years ago, and is caused by global warming. This mean sea level is the one from which the height of mountains is calculated and the altitude of aeroplanes. Melting of sea ice causes no rise in mean sea level. Another factor is that, relieved of the burden of thousands of cubic km of ice at the end of the ice age, places like Scotland gradually rise up, and this rising of the land can persist for many thousands of years after the ice has vanished. In some places there is a seesaw movement where the rising of one part of a plate causes another part hundreds of miles away to descend. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-12T11:32:41.927" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17443" PostTypeId="1" AcceptedAnswerId="17445" CreationDate="2019-07-12T14:46:25.993" Score="3" ViewCount="284" Body="&lt;p&gt;Let us say a car pollutes 1m&lt;sup&gt;3&lt;/sup&gt; of air. Is that pollution attached to that specific air mass or will it fall to the ground or take its own path through the air, independent of the air it first polluted?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And how far can it travel, typically?&lt;/p&gt;&#xA;" OwnerUserId="17348" LastEditorUserId="10735" LastEditDate="2019-07-12T17:30:01.783" LastActivityDate="2019-07-12T17:52:59.140" Title="If a specific mass of air is polluted, will the pollution stick with it?" Tags="|pollution|air|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17444" PostTypeId="2" ParentId="17443" CreationDate="2019-07-12T17:46:02.047" Score="7" Body="&lt;p&gt;Air is a fluid, as such it tends to mix and concentrations, of anything, tend to disperse into the wider volume. Erik's cup of tea metaphor is pretty accurate, currents of air will pull apart your exemplar 1m&lt;sup&gt;3&lt;/sup&gt; and disperse the pollutants therein, the heavier particulate, which is mainly soot, water droplets from combustion, and unburned fuel, will full to the ground fairly quickly. Finer particulate and reactive gases like nitrogen and sulfur oxides will react with water to form acids and fall back to earth with the next rain storm. The exception to this general rule of mixing occurs when there is an &lt;a href=&quot;https://en.wikipedia.org/wiki/Inversion_(meteorology)&quot; rel=&quot;noreferrer&quot;&gt;inversion layer&lt;/a&gt; that puts a &quot;lid&quot; on vertical circulation in a particular area causing a build up of pollutants which often results in &lt;a href=&quot;https://en.wikipedia.org/wiki/Smog&quot; rel=&quot;noreferrer&quot;&gt;smog&lt;/a&gt; formation.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2019-07-12T17:46:02.047" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17445" PostTypeId="2" ParentId="17443" CreationDate="2019-07-12T17:52:59.140" Score="5" Body="&lt;p&gt;Like many of my answers on this Stack Exchange, the answer is yes and no. Part of it depends on the pollutant itself. Let's call the mass by it's technical term, a parcel. There are a couple things that can change the pollution level of the parcel, other than the source (a car in your example):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Chemical reactions between the pollutant, the parcel, light, and water vapor.&lt;/li&gt;&#xA;&lt;li&gt;Diffusion (the parcel gets all stretched and mixes with surrounding parcels as well as the molecules slowly migrating)&lt;/li&gt;&#xA;&lt;li&gt;Deposition (if the pollutant is an aerosol, it could be falling from gravity or be taken up by rain. If it is a gas, it could be reacting with aerosols or the surface of the earth).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Let's put this into math!&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{D\chi}{Dt}=S+R_{prod}-R_{sink}-D-F$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$\chi$&lt;/span&gt; is the concentration of the pollutant, &lt;span class=&quot;math-container&quot;&gt;$S$&lt;/span&gt; is the source, &lt;span class=&quot;math-container&quot;&gt;$R_{prod}$&lt;/span&gt; is the chemical reactions that produce the pollutant, &lt;span class=&quot;math-container&quot;&gt;$R_{sink}$&lt;/span&gt; is the chemical reactions that destroy the pollutant, &lt;span class=&quot;math-container&quot;&gt;$D$&lt;/span&gt; is deposition, and &lt;span class=&quot;math-container&quot;&gt;$F$&lt;/span&gt; is diffusion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How far does this polluted mass travel? Well, that is complicated, as the parcel is immediately stretched and contorted. But an actual answer can be computed. Provided that there is no additional source, the pollutant should be reduced drastically by the equation &lt;span class=&quot;math-container&quot;&gt;$$\tau=\frac{\chi}{R_{sink}+D+F}$$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$\tau$&lt;/span&gt; stands for lifetime. How far will it travel? Well, let's say the wind speed is &lt;span class=&quot;math-container&quot;&gt;$v$&lt;/span&gt;, which has dimensions of length per time. &lt;span class=&quot;math-container&quot;&gt;$\tau$&lt;/span&gt; is a time scale. So we can say that the pollutant will be drastically reduced by &lt;span class=&quot;math-container&quot;&gt;$v\times\tau$&lt;/span&gt; distance downwind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Carbon monoxide is a toxic gas that has a lifetime of 1-2 months. So given a wind speed of about 5 m s&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt;, it may travel 26,297 kilometers. Carbon dioxide, which is also a pollutant from cars, has a lifetime of 35-95 years, so it can travel 14989539 kilometers. Given that the diameter of the earth is 8000 kilometers, you can see why the pollution just spreads over the face of the earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nitrogen monoxide is also a pollutant emitted by cars. However, it is rapidly oxidized and has a lifetime of a few seconds. So it may only travel a few meters.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2019-07-12T17:52:59.140" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17446" PostTypeId="1" CreationDate="2019-07-12T20:35:13.333" Score="2" ViewCount="157" Body="&lt;p&gt;Why increasing transmitter-receiver coil separation in EM survey (&lt;a href=&quot;http://www.geonics.com/html/em31-mk2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;EM31&lt;/a&gt;, also &lt;a href=&quot;https://www.reynolds-international.co.uk/uploads/files/04tssem31.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;) increases depth of penetration? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Suppose there is a horizontal flat conductive layer underneath a flat resistive layer. Why receiver coil records stronger signals at 4 m transmitter-receiver coil spacing compared to 2 m transmitter-receiver coil spacing? What us the physical explanation of this?&lt;/p&gt;&#xA;" OwnerUserId="17351" LastEditorUserId="6031" LastEditDate="2019-07-13T11:01:00.397" LastActivityDate="2019-07-26T00:00:00.680" Title="Transmitter receiver coil separation for Electromagnetic Terrain Conductivity Measurement" Tags="|geophysics|measurements|electromagnetism|field-measurements|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17447" PostTypeId="2" ParentId="17446" CreationDate="2019-07-13T09:40:55.400" Score="2" Body="&lt;p&gt;As described in the question there are two similar coils, one radiates the AC magnetic field (&quot;transmitter&quot;) and the other picks up the weak radiated AC magnetic field produced by subsurface electrical currents induced by the primary field.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Sensitivity vs. Depth&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;There are two modes of operation. The following two figures are from Section 4.1 of &lt;a href=&quot;http://www.geonics.com/pdfs/technicalnotes/tn6.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;GEONICS Technical note #6; Electromagnetic Terrain Conductivity Measurement at Low Induction Numbers&lt;/a&gt;. (more technical notes &lt;a href=&quot;http://www.geonics.com/html/technicalnotes.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;) In both figures the two coils are separated by a horizontal distance &lt;span class=&quot;math-container&quot;&gt;$s$&lt;/span&gt; which is typically a few meters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In &lt;strong&gt;Horizontal mode&lt;/strong&gt; the axes of the two coils point in the horizontal plane. In this orientation the sensitivity always peaks near the surface, and falls off to about 30% at a depth of &lt;span class=&quot;math-container&quot;&gt;$0.4 s$&lt;/span&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/c2BmX.png&quot; alt=&quot;Electromagnetic Terrain Conductivity Measurement&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In &lt;strong&gt;Vertical mode&lt;/strong&gt; the axes of the two coils point &quot;up&quot; or vertically. In this orientation the sensitivity is low near the surface &lt;em&gt;and peaks&lt;/em&gt; at depth of &lt;span class=&quot;math-container&quot;&gt;$0.4 s$&lt;/span&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/fMU1S.png&quot; alt=&quot;Electromagnetic Terrain Conductivity Measurement&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In either case, if &lt;span class=&quot;math-container&quot;&gt;$s$&lt;/span&gt; is twice as big (the coils are twice as far apart) these two shapes will be stretched by the same amount. If &lt;span class=&quot;math-container&quot;&gt;$s$&lt;/span&gt; is 2 meters, the vertical method will have peak sensitivity at 0.8 meters. If &lt;span class=&quot;math-container&quot;&gt;$s$&lt;/span&gt; is 5 meters, vertical sensitivity peaks at 2.0 meters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The two plots can be seen on the right side of Figure 1. in &lt;a href=&quot;https://www.mdpi.com/1424-8220/17/11/2540/htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Application of EM38: Determination of Soil Parameters, Selection of Soil Sampling Points and Use in Agriculture and Archaeology&lt;/a&gt; Kurt Heil and Urs Schmidhalter, Sensors 2017, 17(11), 2540; &lt;a href=&quot;https://doi.org/10.3390/s17112540&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.3390/s17112540&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That article also links to &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0168169914002968&quot; rel=&quot;nofollow noreferrer&quot;&gt;Comparison of the EM38 and EM38-MK2 electromagnetic induction-based sensors for spatial soil analysis at field scale&lt;/a&gt; which may cite further references but it's paywalled.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Sm8Ld.png&quot; alt=&quot;Electromagnetic Terrain Conductivity Measurement&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Figure 1. (Left) Relative cumulative contribution vs depth for vertically (RV(z)) and horizontally (RH(z)) orientated dipoles; (Right) Comparison of the relative responses for vertically (FV(z)) and horizontally (FH(z)) oriented dipoles.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;h2&gt;Yes, that's all fine and dandy... But Why?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;I can't come up with a simple model for why this is true, so I'll have to read further. It's possible someone else will be able to provide a better answer. I think it's related to how the phase of the signals are process, but I'm not sure about that yet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the Computers and Electronics in Agriculture paper &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S016816990000185X&quot; rel=&quot;nofollow noreferrer&quot;&gt;Accuracy issues in electromagnetic induction sensing of soil electrical conductivity for precision agriculture&lt;/a&gt; (also available &lt;a href=&quot;http://extension.missouri.edu/sare/documents/EMImethods2002.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;) K.A.Sudduth, S.T.Drummond and N.R.Kitchen, Volume 31, Issue 3, May 2001, Pages 239-264 &lt;a href=&quot;https://doi.org/10.1016/S0168-1699(00)00185-X&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/S0168-1699(00)00185-X&lt;/a&gt; happens to give equations for these shape, and a clue to where these are from.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/8nONU.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Those equations are close but &lt;span class=&quot;math-container&quot;&gt;$\color{red}{wrong!!}$&lt;/span&gt; they are missing a division &quot;/&quot; sign.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Fig. 2. Relative response of EM38 sensor as a function of distance (adapted from McNeill, 1992).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The equations in the figure have obviously been typed incorrectly, but if I make some simple adjustments they work nicely&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\phi_V(z) = \frac{4z}{(4z^2+1)^{3/2}} $$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\phi_H(z) = 2 - \frac{4z}{(4z^2+1)^{1/2}} $$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where z has to be unitless, so is almost certainly given by:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$z \equiv \frac{\text{depth}}{s}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$s$&lt;/span&gt; is the separation between the two coils as before.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/C0qlv.png&quot; alt=&quot;plot of equations&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Possibly helpful links:&lt;/h2&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0016706114000548&quot; rel=&quot;nofollow noreferrer&quot;&gt;The use of electromagnetic induction techniques in soils studies&lt;/a&gt; (also available &lt;a href=&quot;https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=2462&amp;amp;context=usdaarsfacpub&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://pdfs.semanticscholar.org/7896/794afd56a72e5eb6525182fef383c2420031.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Comparison of Electromagnetic Induction and Direct Sensing of Soil&#xA;Electrical Conductivity&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2019-07-26T00:00:00.680" LastActivityDate="2019-07-26T00:00:00.680" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17448" PostTypeId="2" ParentId="17434" CreationDate="2019-07-13T10:25:59.653" Score="2" Body="&lt;p&gt;I'm sure there are several possible reasons. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not a seismologist, this is an amateur answer only.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Tidal forces&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Local acceleration has very small long-term drifts due to tidal forces from the Sun and the Moon. These will have periods of roughly 1 day as the Earth rotates. Most seismometer data will have been run through a high-pass filter with a much higher cutoff frequency than this (of course along with other filtering). This might be implemented with some baseline restoring function other than a simple filter.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Real changes in local &lt;em&gt;g&lt;/em&gt; due to displacement in the Earth&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Prompt gravity signals -- changes in local &lt;em&gt;g&lt;/em&gt; as mass distribution in the Earth changes -- have been detected, and this kind of measurement may become more widely used in the future. Of course a typical seismometer will not be sensitive to pick this up, unless of course your seismometer is sitting atop a substantial geological event!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/9192/6031&quot;&gt;Prompt gravity signal induced by the 2011 Tohoku-Oki earthquake - could this really be useful for warnings?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earth-planets-space.springeropen.com/articles/10.1186/s40623-019-1006-x&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earthquake-induced prompt gravity signals identified in dense array data in Japan&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://phys.org/news/2016-11-gravity-sensors-earlier-earthquakes.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gravity sensors might offer earlier warning of earthquakes&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h2&gt;Instrumental effects&lt;/h2&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Drift due to thermal changes&lt;/li&gt;&#xA;&lt;li&gt;Tilt due to geological changes (the z accelerometer is no longer pointing in the same direction)&lt;/li&gt;&#xA;&lt;li&gt;Tilt due to improperly mounted seismometer that was shaken loose by the earthquake&lt;/li&gt;&#xA;&lt;li&gt;others...&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2019-07-13T10:25:59.653" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17449" PostTypeId="1" CreationDate="2019-07-13T12:03:23.620" Score="4" ViewCount="214" Body="&lt;p&gt;I want to know how to get the wavelength/frequency of a seismic wave, if I only have a Gaussian source and the velocity (c = 4000m/s) of a medium given.&lt;/p&gt;&#xA;&lt;p&gt;e.g. for a Ricker wavelet it would be easy to get the central frequency and max frequency of the source to compute the wavelength by c/f, but I have some issues with the Gaussian and unfortunately only signals of a Gaussian source.&lt;/p&gt;&#xA;&lt;p&gt;Let's assume my source time function in time domain looks like this:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;source = 1/(2* np.pi * 17.**2) * np.exp( - (t-100)**2 / (2* 17.**2))&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;So a Gaussian with variance of 17 squared and shifted to the right. In the frequency domain it will be centered around zero and I don't really get a maximum frequency as well. Is there a way to find these?&lt;/p&gt;&#xA;" OwnerUserId="17355" LastEditorUserId="2958" LastEditDate="2021-03-08T00:46:40.737" LastActivityDate="2021-03-08T00:46:40.737" Title="wavelength of seismic wave with a gaussian source" Tags="|seismic|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17450" PostTypeId="1" CreationDate="2019-07-13T12:27:44.350" Score="6" ViewCount="1824" Body="&lt;p&gt;What exactly happens at a continental-continental (cc) convergent boundary? I read myself through the web for the last few days and what I came up with is that such a boundary will start as an oceanic-continental (oc) one until the continental plates meet and then a huge falt mountain range like the Himalaja, Alps or Appalacian Mountains is formed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At this point the sources I found gave me conflicting information. Either no subduction of the continental plate occurs or the continental plate is subducted and melts somewhere around 90 to 140 km down. Apparently rockes which where once part of the continental plate melt and resurface. I also heard that this is an area of ongoing research and it isn't fully understood what happens at cc convergent boundaries. So... &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Does no subduction of the continental plate occur? &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Does only a bit of subduction of the continental plate occur, as some of it is pulled down into the deep by the rest of the oceanic plate? &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Does subduction occur at cc boundaries as on oo and oc boundaries, just slower and in a more quiet manner and cc boundaries usually don't last long enough?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="17354" LastActivityDate="2019-07-15T11:40:30.463" Title="Does subduction of continental crust happen at continental-continental convergent boundaries?" Tags="|geophysics|plate-tectonics|mountains|subduction|continent|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17451" PostTypeId="1" CreationDate="2019-07-13T12:38:36.387" Score="-2" ViewCount="180" Body="&lt;p&gt;The Earth's magentic field has been weaking recently, and the sun's magnetic field has been weaking recently, and it is a known fact that when either of these magnetic fields weaken (let alone both of them at the same time) that more cosmic rays reach the Earth - and indeed, throughout the past several decades there has been a continuously-increasing quantity of cosmic rays reaching the Earth - and it is also a known fact that cosmic rays produce C02, and that C02 causes global warming. So how do we know whether or not a huge portion of global warming is being caused by the C02-producing cosmic rays rather than human activitis? Obviously human activities do produce some amount of C02, but has an effort been made to determine how much of a contributor this is, compared to the C02 from cosmic rays?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried Googling for stuff like &quot;do cosmic rays cause global warming&quot; but the only results I am finding are things which discuss some theory about cosmic rays seeding clouds (Henrik Svensmark's theory), which is &lt;em&gt;not&lt;/em&gt; what I am referring to. I could not find a single article that discusses - or tries to debunk - the possibility of global warming being caused by the C02-producing cosmic rays. There might be one somewhere in the search results, but I only have so much time that I am willing to spend digging through Google. Does anyone have an argument against this theory?&lt;/p&gt;&#xA;" OwnerUserId="17357" LastEditorUserId="543" LastEditDate="2019-07-13T21:02:46.593" LastActivityDate="2024-01-10T05:00:58.510" Title="What portion of global warming is caused by radioactive CO2 produced from cosmic rays?" Tags="|climate-change|climate|atmospheric-chemistry|geomagnetism|atmospheric-radiation|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17452" PostTypeId="2" ParentId="17449" CreationDate="2019-07-13T12:47:00.793" Score="4" Body="&lt;p&gt;The Fourier transform of a Gaussian is a Gaussian.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If your signal is given by &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$g(t)=\frac{1}{\sqrt{2 \pi \sigma^2}} \exp\left( -\frac{(t-t_0)^2}{2 \sigma^2}\right)$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;then your frequency spectrum is&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$G(f) = \exp(-2 \pi^2 \sigma^2 f^2),$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where f is the frequency (&lt;span class=&quot;math-container&quot;&gt;$2 \pi \omega).$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'l let you do the substitution with your particular numbers. Enjoy!&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://warwick.ac.uk/fac/sci/mathsys/courses/msc/ma934/resources/notes8.pdf&quot; rel=&quot;noreferrer&quot;&gt;https://warwick.ac.uk/fac/sci/mathsys/courses/msc/ma934/resources/notes8.pdf&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.cse.yorku.ca/~kosta/CompVis_Notes/fourier_transform_Gaussian.pdf&quot; rel=&quot;noreferrer&quot;&gt;http://www.cse.yorku.ca/~kosta/CompVis_Notes/fourier_transform_Gaussian.pdf&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2019-07-13T12:47:00.793" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17453" PostTypeId="2" ParentId="17451" CreationDate="2019-07-13T13:59:32.600" Score="0" Body="&lt;p&gt;I don't know of any mechanism by which cosmic rays can produce substantial amount of CO2 in the atmosphere. Cosmic rays are fast protons and atomic nuclei from the sun and other stars bombarding the upper atmosphere, and have all kinds of subtle effects. They produce small quantities of beryllium 10, for example, but not substantial quantities of CO2. Volcanoes on the other hand do produce huge quantities of CO2. Global warming started long before the human population added large quantities of CO2 to the atmosphere, so there are obviously other causes in addition to mankind's activities, but these other causes don't include cosmic rays. There were plenty of cosmic rays striking the Earth during and before the various ice ages. The abundance of CO2 must be a factor, but up to a point the climate is self regulating. When CO2 abundances increase, plants grow more vigorously and extract it from the atmosphere, but this process can be overwhelmed if abundances increase too rapidly. There have been suggestions that the energy output of the sun is not completely stable and there are occasional fluctuations, but the jury is still out on that one.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-13T13:59:32.600" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17454" PostTypeId="2" ParentId="17450" CreationDate="2019-07-13T14:25:04.130" Score="1" Body="&lt;p&gt;Both of the processes you describe occur; in some cases such as the Himalayas the plates are not subducted and a moving plate, in this case the Indian plate, bulldozes the continental crust ahead of it into a high mountain range. In most cases, such as the Pacific rim for example, subduction is the norm. Where there is subduction there are usually many volcanoes, and this is certainly the case on the Pacific rim. The subducted crust carries rock and water down into the hot mantle, where the friction,heat and water content tend to liquefy it,and it rises to the surface to form volcanoes. To answer your specific question, no. there is no subduction when continental crust meets continental crust, as is the case with the Indian plate meeting the Eurasian plate. Subduction occurs when sea floor spreading forces a plate underneath the lighter and more buoyant continental crust.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-07-15T11:40:30.463" LastActivityDate="2019-07-15T11:40:30.463" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17455" PostTypeId="1" CreationDate="2019-07-13T15:54:40.517" Score="-4" ViewCount="1120" Body="&lt;p&gt;&lt;a href=&quot;https://benpiper.com/2011/07/the-truth-about-carbon-dating/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://benpiper.com/2011/07/the-truth-about-carbon-dating/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The site above explains that Carbon-14 dating is based on a few assumptions, like to deduce the age of an organism by looking at the amount of Carbon-14 left in it and calculating its age based on the time it should have taken for the missing Carbon-14 to decay. However, these assumptions our wrong because the ratio of Carbon-12 to Carbon-14 in the atmosphere has not remained constant and scientists are not able to know. It also states that other radiometric dating methods have similar problems and that these dating methods should be taken with a grain of salt. Is it true that is all assumption and how can we believe these dates?&lt;/p&gt;&#xA;" OwnerUserId="7210" LastActivityDate="2023-07-21T23:34:43.143" Title="Is radiocarbon dating based on assumptions?" Tags="|radioactivity|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17457" PostTypeId="2" ParentId="17455" CreationDate="2019-07-13T21:14:49.983" Score="8" Body="&lt;p&gt;First modern carbon dating does not assume constant Carbon isotope ratios, in fact it is calibrated against known changes in atmospheric concentration, and has been since the 90's. These &lt;a href=&quot;https://books.google.com/books/about/Radiocarbon_Dating.html?id=SjsSugCVvC0C&amp;amp;source=kp_book_description&quot; rel=&quot;nofollow noreferrer&quot;&gt;baselines&lt;/a&gt; were created using annular tree rings which of course reflect the atmospheric carbon when each ring was grown as well as ice core data. This was an issue with the earliest forms of carbon dating (and carbon dating alone) which is why they tended to have huge error bars. Using this as an argument against modern dating is like complaining that automobiles are unsafe because they lack doors or windscreens, it shows the person has not kept up with the development of the technology. Especially considering even the wiki for carbon dating addresses the issue at length, so it is likely willful ignorance. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second dating method are checked against each other, using things like tree rings, stratigraphy, fission tracks, etc. The are also checked against multiple samples. If multiple samples from multiple dating methods arrive at similar dates that is very good evidence of accuracy. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other radiometric dating method don't rely on ambient conditions just basic chemistry so this is a non-issue. If you want to know more about them I suggest you ask a separate question or review the several existing answered questions about them.  &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="8513" LastEditDate="2019-07-15T05:24:40.560" LastActivityDate="2019-07-15T05:24:40.560" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17458" PostTypeId="1" CreationDate="2019-07-14T09:02:26.033" Score="1" ViewCount="26" Body="&lt;p&gt;I stumbled upon this new device called &lt;strong&gt;&lt;a href=&quot;https://teralytic.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Teralytic&lt;/a&gt;&lt;/strong&gt;. Which can measure salination, NPK values and all sorts of things. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately it's sold out and I think when it'll be available again rather expensive. So I as a hobbymaker thought maybe I can build something like this myself? So I was wondering how do they measure these things rigth in the soil itself? The only thing that might be helpful is &lt;a href=&quot;https://ieeexplore.ieee.org/abstract/document/8312001&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; but It doesn't say wheter they used prepared soil samples or just a nomral earth right from their garden or somewhere. Does anyone maybe have an Idea how they could've done it? What techniques have they used?&lt;/p&gt;&#xA;" OwnerUserId="17362" LastEditorUserId="17362" LastEditDate="2019-07-14T13:57:28.083" LastActivityDate="2019-07-14T13:57:28.083" Title="Get NPK values of soil without spectroscopy" Tags="|data-analysis|field-measurements|soil-science|nutrient-cycles|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17460" PostTypeId="1" CreationDate="2019-07-14T20:16:20.797" Score="1" ViewCount="41" Body="&lt;p&gt;I'm from Baltimore Maryland. And our summers can be very intense sometimes a heatwave could put us at 100 degrees and with humidity it could feel like 110 degrees. Now, I have friends from the U.S. Territory of Guam with the same temp or even lower. And some of them say its hotter there and some say it's hotter here. Where's the science to deal with this.&lt;/p&gt;&#xA;" OwnerUserId="17367" LastActivityDate="2019-07-14T22:32:34.890" Title="Does the feel of temperature change, when you're in two different places" Tags="|meteorology|" AnswerCount="1" CommentCount="0" ClosedDate="2019-07-15T15:01:27.670" ContentLicense="CC BY-SA 4.0" />
  <row Id="17461" PostTypeId="1" CreationDate="2019-07-14T20:39:40.300" Score="3" ViewCount="61" Body="&lt;p&gt;Unlike most hurricanes that affect the eastern and central U.S. Barry did not form in the Atlantic. Instead it formed apparently from a low that veered into the Gulf of Mexico from the continental U.S. This graphic shows the historical track of Barry:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8cMTF.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8cMTF.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;sup&gt;(I'm sorry, but I don't remember where I captured this image from.)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once in the gulf, it picked up moisture and energy from the warm gulf waters and eventually became a hurricane, looped back around and appears to be headed back across its former track.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This image from the &lt;a href=&quot;https://oceanservice.noaa.gov/news/historical-hurricanes/&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Hurricane Center&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/eBHa6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eBHa6.jpg&quot; alt=&quot;1851 - 2016&quot;&gt;&lt;/a&gt; shows the storm tracks from 1851 to 2016. While it's hard tell from all the lines, no hurricanes appear to have formed from an air mass originating in the continental U.S.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So just how rare was Barry? It seems to have been extremely rare.&lt;/p&gt;&#xA;" OwnerUserId="2959" LastActivityDate="2019-07-14T20:39:40.300" Title="How rare was Hurrican Barry's storm track?" Tags="|tropical-cyclone|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17462" PostTypeId="2" ParentId="17460" CreationDate="2019-07-14T22:32:34.890" Score="0" Body="&lt;p&gt;Opinions are often very subjective and can't make accurate assessments, especially in matters like this where the two things being compared are vey much alike. The only objective way of doing it is to have accurate temperature and humidity readings over a period of several years for both places. Someone has probably already done that, but I don't know where the best place would be to see their results. Being a relatively small island, Guam should have a marine climate, which is less extreme than continental climates. We have a marine climate here in Britain, and though we often complain about the weather it is less extreme than weather in Europe. A marine climate gives us cooler summers and milder winters, as the temperature is moderated by the sea, which also gives us a damp climate. Guam is nearer the equator than Maryland and is rainforest country, so I would expect it to be fairly humid but not so extreme and variable as Maryland.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-14T22:32:34.890" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17465" PostTypeId="1" AcceptedAnswerId="17467" CreationDate="2019-07-15T08:07:29.923" Score="5" ViewCount="486" Body="&lt;p&gt;I currently read a few papers and one of them stated to forecast solar irradiance using measures of solar radiation.&lt;br&gt;&#xA;I hope this question is not trivial as I'm actually from germany, but if there is a specific difference between these two terms I would be glad if someone could explain it.&lt;/p&gt;&#xA;" OwnerUserId="17374" LastEditorDisplayName="user28185" LastEditDate="2023-02-27T10:03:24.387" LastActivityDate="2023-02-27T10:03:24.387" Title="Solar irradiance/radiation difference" Tags="|atmospheric-radiation|solar-terrestrial-physics|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17467" PostTypeId="2" ParentId="17465" CreationDate="2019-07-15T10:15:43.797" Score="4" Body="&lt;p&gt;Solar irradiation is a measure of the energy delivered by the sun per unit area, watts or joules per square metre for example.. It is often recorded over a specific time period, so it is very much to do with solar radiation, but not exactly the same thing.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-15T10:15:43.797" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="17470" PostTypeId="1" AcceptedAnswerId="17978" CreationDate="2019-07-16T01:10:11.980" Score="3" ViewCount="128" Body="&lt;p&gt;There have been a series of earthquakes (some strong) near &lt;a href=&quot;https://goo.gl/maps/ttnCihDnUcivtWFs8&quot; rel=&quot;nofollow noreferrer&quot;&gt;Broom, Western Australia&lt;/a&gt;. See this screenshot of the &lt;a href=&quot;https://earthquakes.ga.gov.au&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geoscience Australia earthquakes map&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Mu3iF.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Mu3iF.jpg&quot; alt=&quot;Cluster of earthquakes in sea off of Broome, Australia&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I didn't believe there were any faults around this area, or any apparent risk factors for strong earthquakes. Is the strength and number of these earthquakes normal normal, or is something odd happening here?&lt;/p&gt;&#xA;" OwnerUserId="17380" LastEditorUserId="20" LastEditDate="2019-07-17T00:15:09.883" LastActivityDate="2019-09-12T20:20:14.553" Title="Is this series of earthquakes near Broome, Australia normal?" Tags="|earthquakes|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17471" PostTypeId="2" ParentId="10782" CreationDate="2019-07-16T01:40:14.627" Score="1" Body="&lt;p&gt;The coordinates defined in &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/model-data/model-datasets/global-forcast-system-gfs&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Forecast System (GFS -0.5º Degree)&lt;/a&gt; data defined somewhat unusual. In the GFS, longitudes and latitude contains 720 and 361 values respectively. Therefore to convert them to a common geographic coordinate system follow the procedure below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Suppose you are looking for index of coordinate pairs (36.5, -78.5) in the GFS data:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;your_lat_start = x&#xA;your_lat_end = x&#xA;your_lon_start = x&#xA;your_lon_end = x&#xA;your_dataset = half_degree_gfs_dataset&#xA;&#xA;lat_index_start = np.where(np.array(your_dataset['lat'][:].data)==your_lat)[0][0]&#xA;lat_index_end = np.where(np.array(your_dataset['lat'][:].data)==your_lat_end)[0][0] &#xA;lon_index_start = np.where(np.array(your_dataset['lon'][:].data)==your_lon_start)[0]&#xA;lon_index_end = np.where(np.array(your_dataset['lon'][:].data)==your_lon_end)[0][0]&#xA;&#xA;if lat_index_start &amp;gt; lat_index_end:&#xA;    lat_index_start, lat_index_end = lat_index_end, lat_index_start + 1 &#xA;    lon_index_start, lon_index_end = lon_index_start , lon_index_end + 1&#xA;&#xA;dataset[var_name][:,lat_index_start:lat_index_end, lon_index_start:lon_index_end].data&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="17381" LastEditorUserId="595" LastEditDate="2019-07-16T06:14:24.020" LastActivityDate="2019-07-16T06:14:24.020" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17472" PostTypeId="1" CreationDate="2019-07-16T12:26:26.483" Score="2" ViewCount="47" Body="&lt;p&gt;How can I estimate the rainfall rate every ten minutes during a day having the total amount of rainfall during that day ?&lt;/p&gt;&#xA;" OwnerUserId="17383" LastActivityDate="2019-07-16T13:03:20.100" Title="Discrete distribution of daily rainfall" Tags="|meteorology|atmosphere-modelling|rainfall|numerical-modelling|statistics|" AnswerCount="1" CommentCount="3" ClosedDate="2019-08-02T13:23:54.423" ContentLicense="CC BY-SA 4.0" />
  <row Id="17473" PostTypeId="2" ParentId="17470" CreationDate="2019-07-16T12:35:51.973" Score="2" Body="&lt;p&gt;Broome is not all that far away from a plate margin. About 300 miles north of Broome the Australian plate is slipping beneath the Eurasian plate, and this is most likely what is causing the earthquakes. Aftershocks are common after earthquakes, so this is probably what causes the cluster. If such earthquakes are vey infrequent near Broome, that is perhaps because the Australian plate is moving very slowly. Friction sometimes halts it in places and tension builds up as it I tries to move forward but is prevented. When the friction is no longer enough, something gives, and that part of the plate lurches forward again. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-16T12:35:51.973" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17474" PostTypeId="2" ParentId="17472" CreationDate="2019-07-16T13:03:20.100" Score="0" Body="&lt;p&gt;Put a cylindrical beaker out in the open at mid day. Remove it at mid day on the following day. Measure the depth of the accumulated rainfall and divide by 24 to give the average rainfall per hour, and divide that by 6 to give the average per 10 mins. In the summer, some of your collected rainwater will be lost through evaporation, so to find that, put your beaker of water outside, but under some sort of roof. Measure the depth when you put it out, and measure it next day when you take it in. That will give an idea of losses due to evaporation, which reckoned in losses every ten minutes would by tiny. If there is not much rain but plenty of hot sunlight, things become tricky, because you will be measuring very tiny quantities. Other than that, you could camp outside and weigh your beaker every 10 minutes, but that's not something I would do myself. The roof I mentioned is only necessary if it is raining, because rain would destroy your figures for evaporation.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-16T13:03:20.100" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17476" PostTypeId="2" ParentId="16480" CreationDate="2019-07-16T16:59:24.010" Score="1" Body="&lt;p&gt;Apparently, the IERS publishes values for each 0 h of UTC in their bulletins. I myself thought otherwise, but I recently noticed, in a geodesy exam, that they mentioned UTC for the daily parameters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Upon closer look at the Bulletins themselves, I was able to confirm this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AFVFI.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AFVFI.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although using UT1 instead of UTC for interpolation should cause only tiny errors, smaller than the posted errors of the final values.&lt;/p&gt;&#xA;" OwnerUserId="17236" LastActivityDate="2019-07-16T16:59:24.010" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17478" PostTypeId="1" AcceptedAnswerId="17495" CreationDate="2019-07-16T18:46:51.783" Score="9" ViewCount="687" Body="&lt;p&gt;I'm trying to understand what weather forecasts mean more precisely. As I understand it from reading Wikipedia, blogs, etc., the percentage value for rain/precipitation that you see in a forecast is technically called the &quot;probability of precipitation&quot;. To quote the National Weather Service webpage:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Mathematically, PoP is defined as follows: PoP = C x A where &quot;C&quot; = the confidence that precipitation will occur somewhere in the forecast area, and where &quot;A&quot; = the percent of the area that will receive measureable precipitation, if it occurs at all.&#xA;So... in the case of the forecast above, if the forecaster knows precipitation is sure to occur ( confidence is 100% ), he/she is expressing how much of the area will receive measurable rain. ( PoP = &quot;C&quot; x &quot;A&quot; or &quot;1&quot; times &quot;.4&quot; which equals .4 or 40%.)&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This definition does not seem well stated to me, for the reason that &quot;confidence&quot; is (presumably) not uniform across an area. For instance, the phrase &quot;how much of the area &lt;strong&gt;will&lt;/strong&gt; receive measurable rain&quot; seems odd, since a forecast would (presumably) only be able to give a probabilistic estimate for this area. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's cook up an example. Consider a town (the forecast area) consisting of two parts of equal area (called north side and south side). Each point in the north side will be rained on with 100% probability tomorrow, and each point in the south side will be rained on with 50% probability (at every point) tomorrow. What is the PoP in this example? At face value, the definition could be interpreted as implying that the PoP is 100%, since precipitation will occur &lt;strong&gt;somewhere&lt;/strong&gt; in the forecast area. However, this value seems intuitively unsatisfying, since some people might not get any rain.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's what I might expect a more precise definition to be. If &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; is the area and &lt;span class=&quot;math-container&quot;&gt;$C(x)$&lt;/span&gt; is the &quot;pointwise confidence function&quot; depending on a point (location) &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt;, then define &#xA;&lt;span class=&quot;math-container&quot;&gt;$$PoP = \frac{1}{area(A)}\int_{A} C(x)\, dx.$$&lt;/span&gt;&#xA;In words, this is just the expected value of &lt;span class=&quot;math-container&quot;&gt;$C(x)$&lt;/span&gt;, or the probability that a randomly located person would see rain over the specified time interval. In practice, of course the integral would be estimated based on actual measurement sites. If such a formula is indeed an accurate definition, then I'd be satisfied. In the above example, the PoP would be 75%. (The official definition could in essence be viewed as a shorthand that is more useful for those without any background in calculus.) If this definition is not correct, then some explanation would be helpful.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've read web articles with statements like the &lt;a href=&quot;https://gizmodo.com/what-it-really-means-when-theres-a-50-percent-chance-of-1785465340&quot; rel=&quot;nofollow noreferrer&quot;&gt;following&lt;/a&gt;: &quot;As a student and observer of meteorology, it constantly bums me out that people do not understand what it means when someone says there’s an “X% chance of rain” tomorrow. A 50 percent chance of rain does not mean there’s a 1-in-2 chance that you’re going to get wet.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's not clear to me why &quot;A 50 percent chance of rain means there’s a 1-in-2 chance that you’re going to get wet&quot; would be an inaccurate interpretation of PoP. If the definition I suggested above is correct, then it is perfectly correct to say that a stationary observer placed at a random location in this scenario would have a 50% chance of getting wet. Am I missing something, or is this author being careless?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't have any background in meteorology, and in particular I don't have much of a sense of how PoP is actually computed in practice.&lt;/p&gt;&#xA;" OwnerUserId="17387" LastEditorUserId="543" LastEditDate="2021-07-20T04:55:54.210" LastActivityDate="2021-07-20T05:11:22.577" Title="Why don't I have a 1-in-2 chance of getting rained on if the forecast says 50% probability of precipitation?" Tags="|weather-forecasting|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="17480" PostTypeId="2" ParentId="17470" CreationDate="2019-07-16T19:21:54.860" Score="4" Body="&lt;p&gt;Are you confusing faults with tectonic plate boundaries?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Australia is in the middle of a tectonic plate, but there are &lt;a href=&quot;https://cooberpedytimes.com/2008/09/26/faultlines-weaving-their-way-across-southern-australia/&quot; rel=&quot;nofollow noreferrer&quot;&gt;countless faults&lt;/a&gt; within the plate, as within all the other plates. Each plate is stressed &amp;amp; eventually rock adjacent to some faults moves resulting in a &lt;a href=&quot;https://en.wikipedia.org/wiki/Intraplate_earthquake&quot; rel=&quot;nofollow noreferrer&quot;&gt;intraplate earthquakes&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the &lt;a href=&quot;https://www.ga.gov.au/scientific-topics/community-safety/earthquake&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geoscience Australia&lt;/a&gt; website states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Although Australia is not on the edge of a plate, the continent experiences earthquakes because the Indo-Australian plate is being pushed north and is colliding with the Eurasian, Philippine and Pacific plates. This causes the build up of mainly compressive stress in the interior of the Indo-Australian plate which is released during earthquakes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-07-16T19:21:54.860" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17481" PostTypeId="1" CreationDate="2019-07-16T22:57:22.563" Score="2" ViewCount="390" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HB5j7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HB5j7.jpg&quot; alt=&quot;dridg&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please identify the fossil in the picture below. size of pebble is around 40mm diameter and the pebble had been broken to reveal the internal structure.&lt;/p&gt;&#xA;" OwnerUserId="17388" LastActivityDate="2019-07-18T22:27:15.493" Title="Fossil in Chert pebble picked up on a Kent beach" Tags="|fossils|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="17483" PostTypeId="1" AcceptedAnswerId="17518" CreationDate="2019-07-17T01:37:50.150" Score="4" ViewCount="389" Body="&lt;p&gt;Diabase is often considered to be relatively erosion resistant. We can generally find diabase dikes cross-cutting various strata through the geologic landscape, wherein, the diabase dike or sill is rather intact as a structure while the surrounding strata have eroded around it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, differential weathering and erosion depend on the relative susceptibility among those rocks which are next to each other, but if you take into consideration the Goldich Dissolution Series, shouldn't diabase and other basalt-like bodies be easily eroded? Basalts and diabase have calcium plagioclase as a major mineral component. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I could see how shales could weather and erode much more quickly but it seems unlikely that a limestone in an arid environment or a mature quartz arenite sandstone ever would do so. &lt;/p&gt;&#xA;" OwnerUserId="14316" LastActivityDate="2019-07-20T00:47:47.153" Title="Why is diabase/dolerite erosion resistant?" Tags="|petrology|erosion|weathering|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17486" PostTypeId="2" ParentId="17481" CreationDate="2019-07-17T06:58:08.543" Score="0" Body="&lt;p&gt;These are fossilised crinoid discs. Crinoids are also known as sea lilies because of their plant-like appearance, but in fact they are animals related to starfish and sea urchins. There were many species, some modern representatives of which are still alive today. They had a long stem composed of stacked discs and topped by a flower-like bunch of feathery tentacles which filtered particles of food from the passing currents. The stem was anchored at the base to rocks on the sea floor. When they died, the stem tended to disintegrate into separate discs, and your specimen shows three or possibly four of them. They probably date from the Cretaceous. Chert, also known as flint, is a deposit of silicon dioxide which forms nodules in chalk sediments as they solidify.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-17T06:58:08.543" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17488" PostTypeId="1" CreationDate="2019-07-17T13:21:27.103" Score="4" ViewCount="23" Body="&lt;p&gt;The World Meteorological Organisation (WMO) &lt;a href=&quot;https://www.wmo-sat.info&quot; rel=&quot;nofollow noreferrer&quot;&gt;Observing Systems Capability Analysis and Review (OSCAR)&lt;/a&gt; Tool describes the &lt;a href=&quot;https://www.wmo-sat.info/oscar/instruments/view/180&quot; rel=&quot;nofollow noreferrer&quot;&gt;High-Resolution Imager (HRI)&lt;/a&gt; (which flies on Pléades-1A and -1B, among other satellites) fire fractional cover capability as limited to &quot;daylight only&quot;.  The same for Landsats &lt;a href=&quot;https://www.wmo-sat.info/oscar/instruments/view/375&quot; rel=&quot;nofollow noreferrer&quot;&gt;Operational Land Imager (OLI)&lt;/a&gt;. But fires should be visible at night, why would the fire fractional cover capability be limited to daylight observations?  Do they switch off the sensor to limit energy/bandwidth/storage or is there a more technical reason?&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2019-07-17T13:21:27.103" Title="Why does the OSCAR database describe Landsats fire identification as &quot;daylight only&quot;?" Tags="|earth-observation|fire|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17489" PostTypeId="1" CreationDate="2019-07-17T20:03:55.430" Score="1" ViewCount="595" Body="&lt;p&gt;I've tried: &#xA;pip install wafo&#xA;pip install wafo==0.3.1&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The instructions of readme provide a 2 step installation process but it fails on the first one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am using windows 10 and python 3.6.1.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Right now, rather than assistance to make it work I would just like to know if I'm on a fools errand or if its actually possible to install wafo for python under configurations like I have. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Appreciate any reply.&lt;/p&gt;&#xA;" OwnerUserId="17393" LastActivityDate="2019-12-18T07:38:34.603" Title="Anyone sucessfully installed pywafo for Python 3 under windows OS?" Tags="|python|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17494" PostTypeId="1" CreationDate="2019-07-18T06:45:41.153" Score="5" ViewCount="586" Body="&lt;p&gt;What is this geomorphological form located at &lt;a href=&quot;https://goo.gl/maps/MxwM9omfvnHxAwPT6&quot; rel=&quot;nofollow noreferrer&quot;&gt;Vitrolles, France&lt;/a&gt;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And how is it formed? It is like a 'raised flat land', or a base of a hill where the top 80% is cut, leaving only the wide, flat base.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GlCZO.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GlCZO.jpg&quot; alt=&quot;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17400" LastEditorDisplayName="user12525" LastEditDate="2019-07-19T06:23:23.820" LastActivityDate="2019-07-19T17:09:45.487" Title="What is this geomorphological form?" Tags="|geography|geomorphology|" AnswerCount="5" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17495" PostTypeId="2" ParentId="17478" CreationDate="2019-07-18T09:12:24.707" Score="6" Body="&lt;p&gt;I agree that the PoP = C x A that we see on a lot of websites leaves something to be desired.  It gets across the loose idea that the definition involves the area affected as well as the probability of occurrence, which is fine for most casual readers but can be frustrating for more inquisitive minds.  How much are the confidence and the area estimated from ensemble forecasts versus expert judgement?  How was it done before ensemble NWP started in the 1990s?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyway, there’s an interesting survey by Stewart et al (2016) that gives a broader overview of how different meteorologists use the phrase “probability of precipitation”.  They categorise the PoP = C x A usage as following the NWS Operations Manual (1984), which is nicely summarized in a comment by Schaefer and Livingstone (1990).  In short, your interpretation in terms of expectations is correct and, as you mention, they describe it in terms of a sum over a hypothetical network of points rather than a continuous integral:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\textrm{PoP} = \frac{1}{N} \sum_{i=1}^N E[R_i]$&lt;/span&gt;,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$R_i$&lt;/span&gt; equals 1 if it rains at station &lt;span class=&quot;math-container&quot;&gt;$i$&lt;/span&gt; and 0 if it doesn't.  In your Pluieville example, this could be approximated as a town with one rain gauge in the north and one in the south, giving PoP = (1.0 + 0.5)/2 = 0.75.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know for sure, but it wouldn't surprise me if these things are still calculated by subsampling gridded NWP models at actual rain gauge network locations, which would allow for comparable long-term verification of the probabilistic forecasts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Stewart, A.E., C.A. Williams, M.D. Phan, A.L. Horst, E.D. Knox, and J.A. Knox, 2016: &lt;a href=&quot;https://doi.org/10.1175/WAF-D-15-0058.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Through the Eyes of the Experts: Meteorologists’ Perceptions of the Probability of Precipitation&lt;/a&gt;. Wea. Forecasting, 31, 5–17, doi:10.1175/WAF-D-15-0058.1 &lt;/p&gt;&#xA;&#xA;&lt;p&gt;National Weather Service, 1984: Zone and local forecasts. NWS Operations Manual W/OM15.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Schaefer, J.T. and R.L. Livingston, 1990: &lt;a href=&quot;https://doi.org/10.1175/1520-0434(1990)005%3C0354:OIOTOP%3E2.0.CO;2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Operational Implications of the “Probability of Precipitation”&lt;/a&gt;. Wea. Forecasting, 5, 354–356, doi:10.1175/1520-0434(1990)005&amp;lt;0354:OIOTOP&gt;2.0.CO;2 &lt;/p&gt;&#xA;" OwnerUserId="106" LastEditorUserId="106" LastEditDate="2019-10-18T11:20:58.880" LastActivityDate="2019-10-18T11:20:58.880" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17496" PostTypeId="2" ParentId="17494" CreationDate="2019-07-18T09:20:18.627" Score="3" Body="&lt;p&gt;If the flat land formed as a river terrace, we could call it a raised terrace. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the flat land is a resistant layer of rock, then we could call it a low plateau. (the thin layer of white rock immediately below the land surface might suggest this is the correct interpretation.) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If it formed by erosion in the past, it could be a peneplain. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The correct word depends on the origin of the feature. &lt;/p&gt;&#xA;" OwnerUserId="17404" LastActivityDate="2019-07-18T09:20:18.627" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17497" PostTypeId="2" ParentId="17494" CreationDate="2019-07-18T10:11:40.177" Score="2" Body="&lt;p&gt;Your marker seems to indicate an escarpment, which is a long ridge where a cliff or a steep slope separates low ground from higher ground. These slopes or cliffs can have a number of different causes, but as I have never visited the one in your photo I wouldn't like to hazard a guess as to what caused this particular one.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-18T10:11:40.177" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17498" PostTypeId="2" ParentId="17494" CreationDate="2019-07-18T11:56:18.583" Score="3" Body="&lt;p&gt;I couldn't find any paper describing the geomorphology of the zone, but this is refered as &lt;em&gt;Plateau de Vitrolles&lt;/em&gt;; there is an archaeological deposit close to the point you marcked (&lt;a href=&quot;https://www.persee.fr/doc/dam_0184-1068_1999_num_22_1_1131?pageid=t1_289&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can find a &lt;a href=&quot;https://lesdefinitions.fr/plateau&quot; rel=&quot;nofollow noreferrer&quot;&gt;french geologic definition of plateu at this site&lt;/a&gt;. I guess the term is equivalent to plateau on US reference bibliography, but there migth be some little differences.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To shortly answer your question about how was it formed, &lt;a href=&quot;https://www.google.com/maps/place/13127+Vitrolles,+Francia/@43.4573318,5.2699724,15z/data=!4m5!3m4!1s0x12c9ef264c1ad325:0x40819a5fd96fe40!8m2!3d43.458598!4d5.249703&quot; rel=&quot;nofollow noreferrer&quot;&gt;the &lt;em&gt;Ruisseau du Bondon&lt;/em&gt; excavated the plateau&lt;/a&gt;, forming the slopes and the valley.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To deeply answer a reference to a local geomorphologic study would be needed. There should be some study on geomorphology journals, as the zone looks interesting. If you are at University you could make a research for &quot;Plateau de Vitrolles&quot; and you migth find a complet explanation from local geologists.&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-07-19T17:09:45.487" LastActivityDate="2019-07-19T17:09:45.487" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17500" PostTypeId="2" ParentId="17481" CreationDate="2019-07-18T22:27:15.493" Score="1" Body="&lt;p&gt;It a sea urchin fragment, or at least a natural mold of them. They have both the rings and the angliar joints. It is not uncommon for them to break up into clusters of those plates. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RfLk3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RfLk3.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2019-07-18T22:27:15.493" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17502" PostTypeId="2" ParentId="17494" CreationDate="2019-07-18T23:36:17.297" Score="4" Body="&lt;p&gt;There are a couple of possibilities, depending on what you're paying the most attention to.  This falls in an overlap area of terms that vary from region to region and even from person to person. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The key thing to notice in your photo is the whitish band running along the top of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Escarpment&quot; rel=&quot;nofollow noreferrer&quot;&gt;escarpment&lt;/a&gt; that borders your landform.  This shows that it's held up by a resistant, mostly horizontal, layer of sedimentary rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.vitrolles13.fr/habiter/cadre-de-vie/le-plateau/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This French page&lt;/a&gt; refers to it as a &lt;strong&gt;&lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Cuesta&quot; rel=&quot;nofollow noreferrer&quot;&gt;cuesta&lt;/a&gt;&lt;/em&gt;&lt;/strong&gt;; this is plausible, but the strata underlying cuestas usually slope more than what appears in your picture.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/0/00/Cuesta_schematic1.PNG/800px-Cuesta_schematic1.PNG&quot; alt=&quot;cuesta image from Wikipedia&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(generalized cuesta image from Wikipedia)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Plateau&quot; is also plausible, but this is not very specific. The landform in your picture doesn't have quite the extent of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Colorado_Plateau&quot; rel=&quot;nofollow noreferrer&quot;&gt;Colorado Plateau&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Table_(landform)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tableland&lt;/a&gt;&lt;/em&gt;&lt;/strong&gt; or &lt;em&gt;table&lt;/em&gt; is probably the most generic name for the entire regional structure under the rock layer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are talking about the remnant under the pin in your image (and especially if this were in America),  then we'd have no trouble calling it a &lt;strong&gt;&lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Mesa&quot; rel=&quot;nofollow noreferrer&quot;&gt;mesa&lt;/a&gt;&lt;/em&gt;&lt;/strong&gt; or even a  &lt;strong&gt;&lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Butte&quot; rel=&quot;nofollow noreferrer&quot;&gt;butte&lt;/a&gt;&lt;/em&gt;&lt;/strong&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/9/9b/Over_Monument_Valley%2C_Navajo_Nation.jpg/320px-Over_Monument_Valley%2C_Navajo_Nation.jpg&quot; alt=&quot;mesa&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;(Wikipedia image of a mesa in Monument Valley)&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2019-07-19T13:25:05.277" LastActivityDate="2019-07-19T13:25:05.277" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="17506" PostTypeId="1" CreationDate="2019-07-19T08:06:00.837" Score="4" ViewCount="48" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Notosuchia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Notosuchia&lt;/a&gt; has a long and storied past. They seem to have gotten by just fine with dinosaurs dominating the makeup of mid and late Mesozoic megafauna. Despite dinosaurs having more developed and specialized anatomy, notosuchians thrived with diversity of their own.&lt;/p&gt;&#xA;&lt;p&gt;Most importantly, many of these are large, terrestrial, cursorial carnivores -- exactly the niche of the more established dinosaurs. This obvious competition does not seem to have fazed notosuchian diversity.&lt;/p&gt;&#xA;&lt;p&gt;Notosuchians survived the K-Pg extinction event with Sebecosuchia. Together with the unrelated mekosuchines, long-legged terrestrial crocodylomorphs managed to eke out an existence for a few more tens of millions of years. However, they only thrived in areas with no significant mammalian carnivorous megafauna - pre-Interchange South America, Australia and Oceanic islands, mainly.&lt;/p&gt;&#xA;&lt;p&gt;For some reason, the ecological advantages that allowed terrestrial crocodilians to coexist with dinosaurs and terror birds did not apply in the middle Miocene.&lt;/p&gt;&#xA;&lt;p&gt;Since this era is also the one where large, competent mammalian predators had evolved, this implies that they were able to confine the notosuchians and mekosuchines to more specific areas and niches until they eventually went extinct.&lt;/p&gt;&#xA;&lt;p&gt;Of course the climate of the Miocene was much different from that of the Mesozoic, I just don't know how that applies.&lt;/p&gt;&#xA;&lt;p&gt;Is there something about mammals that made them harder to compete against even dinosaurs? Or is the bigger story more nuanced?&lt;/p&gt;&#xA;" OwnerUserId="17412" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-07-19T08:06:00.837" Title="Why did notosuchians and similar crocodylomorphs thrive in the Jurassic-Cretaceous but fail to compete with adequate mammalian competitors?" Tags="|paleontology|ecology|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17507" PostTypeId="1" CreationDate="2019-07-19T09:19:45.183" Score="6" ViewCount="620" Body="&lt;p&gt;The gist of the BBC News article &lt;a href=&quot;https://www.bbc.com/news/uk-scotland-highlands-islands-49030378&quot; rel=&quot;nofollow noreferrer&quot;&gt;'Incredibly rare rainbow' photographed in Highlands&lt;/a&gt; is that while it has several familiar features, there are aspects that are still unexplained.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Are there really aspects of this particular multiple rainbow that are currently unexplained by science?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;update:&lt;/strong&gt; there is now a &lt;a href=&quot;https://twitter.com/bbc5live/status/1152107473941278720&quot; rel=&quot;nofollow noreferrer&quot;&gt;tweet about it&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/UeLCo.jpg&quot; alt=&quot;rainbow at Loch Lochy in the Highlands&quot; /&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The rainbow was photographed at Loch Lochy in the Highlands, SAXAPHONEJAN/BBC WEATHER WATCHERS&lt;/p&gt;&#xA;&lt;p&gt;Unusually, the colours of the third rainbow are in the same order as the main one it was attached to.&lt;/p&gt;&#xA;&lt;p&gt;BBC Weather presenter Simon King said: &amp;quot;This has scratched a few heads as this is something incredibly rare.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;The meteorologist said the rainbow had the characteristics of both of what are known as a twinned rainbow and supernumerary rainbow.&lt;/p&gt;&#xA;&lt;p&gt;Supernumerary bows are formed by small, similar-sized raindrops which then create ripple-like rainbows.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-07-23T22:26:53.350" Title="Is this particular multiple rainbow unexplained by science?" Tags="|atmosphere|atmospheric-optics|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="17511" PostTypeId="2" ParentId="17494" CreationDate="2019-07-19T15:20:52.073" Score="4" Body="&lt;p&gt;There is a similar and bigger chalk plateau at &lt;a href=&quot;https://www.google.com/maps/place/Font+d&amp;#39;Urle+station/@44.8777217,5.2912641,7319m/data=!3m1!1e3!4m5!3m4!1s0x478aa0dc262716ad:0x57983349345a9225!8m2!3d44.908138!4d5.333895&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;plateau d'urle&quot; in France&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That one looks like a &quot;chalk plateau of continental shelf origin with straight channels eroded into the underlying clays&quot;, by it's flatness and proximity to the sea. The geologists write that the chalk is a &lt;a href=&quot;https://www.geoforum.fr/topic/31803-stratotypes-rognacien-vitrollien/&quot; rel=&quot;nofollow noreferrer&quot;&gt;freshwater lake chalk deposit&lt;/a&gt; due to it's fossils.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sediments are layed down by different processes with different chemistries... Very tough pure chalk, softer chalk and silt deposits vary in bands, corresponding to underwater currents and rivers that vary over time. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The top layers erode away leaving a very tough protective chalk. The water flow at Vitrolles has stayed shallow, so that it has not tunneled deep under the chalk cap, it has burrowed straight channels just under and through it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;top layer (freshwater lake chalk) 60 million years... red stripes: Calcaires de Vitrolles (Montien-Tertiaire)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;lower layer (clay and sandstone) 65-70 million years  ... beige no stripes: Argiles et grès à lentilles calcaires (Rognacien-Secondaire) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NoVpN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NoVpN.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2019-07-19T15:59:38.820" LastActivityDate="2019-07-19T15:59:38.820" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17513" PostTypeId="1" CreationDate="2019-07-19T19:36:51.477" Score="1" ViewCount="41" Body="&lt;p&gt;What are the main factors that contribute to the temperature fluctuations/cycles of a location? Is the earth's temperature cycle dictated mainly by the temperature cycle of the ocean? How does the ocean's heat storage affect the temperature of the atmosphere and thus the seasonality that we human's feel?&lt;/p&gt;&#xA;" OwnerUserId="17417" LastActivityDate="2019-07-19T21:29:46.587" Title="Temperature of the earth" Tags="|atmosphere|climate|oceanography|temperature|" AnswerCount="1" CommentCount="0" ClosedDate="2019-07-20T10:33:27.217" ContentLicense="CC BY-SA 4.0" />
  <row Id="17514" PostTypeId="2" ParentId="17513" CreationDate="2019-07-19T21:29:46.587" Score="1" Body="&lt;p&gt;The oceans have a huge effect on the climate and temperature of the various regions of the world. Climates fall into two categories: marine and continental. In Britain we have a marine climate, which protects us from the extremes of the European continental climate. Our winters are milder, our summers cooler, because of the proximity of the Atlantic and the warm Gulf Stream coming up from the Gulf of Mexico. It also gives us a damper climate, with more mist and rain. This moderating effect and increased dampness and humidity is characteristic of marine climates. In the S.Pacific they have El Nino, a strange subtropical current which reverses every ten years or so, causing droughts and other adverse effects for the countries of the region. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Galapagos archipelago is another example of a marine climate, in this case cooled by the Humboldt Current coming up the coast of Chile from the Southern Ocean. The Galapagos Islands are on the equator, yet the climate is only subtropical and the waters are cool enough for penguins to thrive. These cold currents, like the Benguela current coming up the west coast of S.Africa, are rich in nutrients and in fish. The Benguela Current has strange effects on the climate of Namibia.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-19T21:29:46.587" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17517" PostTypeId="2" ParentId="13262" CreationDate="2019-07-20T00:39:42.137" Score="1" Body="&lt;p&gt;You are entirely correct. &lt;a href=&quot;https://doi.org/10.1111/j.1525-1314.1997.00038.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;Todd and Engi&lt;/a&gt; write:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The mineral assemblages of rocks at the surface lie on a locus of&#xA;  &lt;em&gt;P&lt;/em&gt;–&lt;em&gt;T&lt;/em&gt;-conditions… It must be stressed…does &lt;em&gt;not&lt;/em&gt; imply a &lt;em&gt;P&lt;/em&gt;–&lt;em&gt;T&lt;/em&gt;-distribution or geotherm realized at any one time during the orogenic evolution of this area. Even assuming the &lt;em&gt;P&lt;/em&gt;–&lt;em&gt;T&lt;/em&gt;-values&#xA;  reflect maximum metamorphic conditions, these were established at&#xA;  different times in different areas…show the integrated effect of all&#xA;  the tectonometamorphic processes…i.e. the sum of burial, heating,&#xA;  tectonic and erosional unroofing and cooling.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Notwithstanding, the metamorphic field gradient is still useful, particularly when comparing different sets of rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each of the samples in your figure (A, B and C) is a single rock and looking at it tells you the history of this rock and this rock alone. When studying a large area (a &quot;field&quot;) there will be many rocks, that may differ from each other in their individual &lt;em&gt;P&lt;/em&gt;–&lt;em&gt;T&lt;/em&gt;-path. For example, in a rock suite that is now dipping 90°, one might argue that walking 3 kilometres on the surface equals 1 kbar of pressure, equals about 3 kilometres of depth. Because of that, each sample along the transect will have experienced different temperatures, with ideally the deeper ones also being the hotter ones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By choosing a convenient reference point (maximum temperature of an individual sample), and connecting all samples along a transect, you can get an estimate of a &lt;em&gt;P&lt;/em&gt;–&lt;em&gt;T&lt;/em&gt; gradient, which can approximate a geotherm (under many assumptions). The same Todd and Engi paper has this figure:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Tqgp3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Tqgp3.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Each of the lines is based on several dozens of individual samples. Based on this representation of the data, they go on to conclude:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The metamorphic field gradients and age determinations and consistent&#xA;  with two stages of metamorphism. The first stage created the field&#xA;  gradients preserved in the northern part of the field area. The second&#xA;  thermal pulse affected only the south-eastern part of the field area.&#xA;  This occurred at a later time, under lower pressure conditions.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Reaching those conclusions is only possible when condensing the 100 or so individual samples they used (i.e. 100 individual &lt;em&gt;P&lt;/em&gt;–&lt;em&gt;T&lt;/em&gt;-path loops) to what turned out to be only two metamorphic field gradients.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Todd, C. S. and Engi, M. (1997), Metamorphic field gradients in the Central Alps. Journal of Metamorphic Geology, 15: 513-530. doi:&lt;a href=&quot;https://doi.org/10.1111/j.1525-1314.1997.00038.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.1111/j.1525-1314.1997.00038.x&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-07-20T00:39:42.137" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17518" PostTypeId="2" ParentId="17483" CreationDate="2019-07-20T00:47:47.153" Score="2" Body="&lt;p&gt;Diabase is indeed relatively erosion resistant. One of the reasons is grain size.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider the two other chemical equivalent of diabase: gabbro (coarse-grained) and basalt (glassy and fine-grained), which should potentially be similarly erosion resistant. This is not the case. Both gabbro and basalt erode very easily.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Coarse-grained rocks, in general, erode easily. The large grain size means it is relatively easy to dislodge individual grains out of the rock. You don't need a lot of water, for instance, to percolate between the not-many grain boundaries and release them. To make it worse, gabbros are full of minerals that are easily erodable such as plagioclase and olivine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, basalts also tend to weather easily. Having cooled fast, they are usually glassy which tends to crack during cooling. Glass is general is less resistant to chemical alteration than minerals, under similar conditions. Basalts also contain gas bubbles, which cause weakness spots in which the rock can break, leading to preferred weathering.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Diabase is fine grained, and contains no glass. It does not suffer from these two conditions. It is composed of very fine interlocking crystals that are very hard to dislodge, and is not penetrable by fluids.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, remember that it is all relative. A diabase will still weather faster than even the worst type of granite.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-07-20T00:47:47.153" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17519" PostTypeId="1" CreationDate="2019-07-20T14:56:51.697" Score="4" ViewCount="74" Body="&lt;p&gt;I'm trying to find maps of realtime (or at least periodically updated / semi-realtime) gravity maps of Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was hoping that &lt;a href=&quot;https://earth.esa.int/web/guest/missions/esa-operational-eo-missions/goce&quot; rel=&quot;nofollow noreferrer&quot;&gt;GOCE&lt;/a&gt; might have something like this available, but I've been hitting a wall. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any such maps available?&lt;/p&gt;&#xA;" OwnerUserId="2575" LastActivityDate="2019-07-21T20:06:07.217" Title="Realtime planetary gravity maps?" Tags="|mapping|gravity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17522" PostTypeId="2" ParentId="12283" CreationDate="2019-07-21T11:26:14.157" Score="1" Body="&lt;p&gt;I believe that tropical storms contributes a little to cooling the earth by transporting warmer matter higher into the atmosphere where there is less of a greenhouse effect. By this I mean there is less gas that can trap (capture/reradiate) Infrared between the the hotter material and outer space.  However it may be that the albedo effect is far greater.&lt;/p&gt;&#xA;" OwnerUserId="17425" LastActivityDate="2019-07-21T11:26:14.157" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17524" PostTypeId="2" ParentId="17519" CreationDate="2019-07-21T18:52:00.213" Score="5" Body="&lt;p&gt;For sure this is not available. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;To create those maps takes several dozens Earth orbits by GOCE (one orbit ~90 minutes) and possibly many more to bring up the signal to noise&lt;/li&gt;&#xA;&lt;li&gt;Which gravitational features would you expect to vary significantly on any human timescale, so that creating such a scan would make sense?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;This does not mean however, that no gravitational changes over time can be detected. &lt;a href=&quot;https://www.youtube.com/watch?v=Dyq6kGKPQ5g&quot; rel=&quot;nofollow noreferrer&quot;&gt;ESA produced a video&lt;/a&gt; visualising data that showcases how GRACE and GOCE worked to produce ~10 snapshots per year from 2009-2012 to measure Antarctic ice loss. So continuing your search along those lines will surely lead to positive results.&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="489" LastEditDate="2019-07-21T20:06:07.217" LastActivityDate="2019-07-21T20:06:07.217" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17526" PostTypeId="1" CreationDate="2019-07-22T10:41:59.343" Score="5" ViewCount="622" Body="&lt;p&gt;I admit that this is not a genuinely earth sience question, but since there is no stack exchange site genuinely devoted to general ecology, I dare to ask it here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From a table in the &lt;a href=&quot;https://www.wikiwand.com/de/Emissionsrechtehandel#/Emissionsrechtehandel_bei_Treibhausgasen&quot; rel=&quot;nofollow noreferrer&quot;&gt;German Wikipedia article on emissions trading&lt;/a&gt; I've learned that the &lt;a href=&quot;https://www.wikiwand.com/en/Global_warming_potential&quot; rel=&quot;nofollow noreferrer&quot;&gt;global warming potential&lt;/a&gt; of &lt;a href=&quot;https://www.wikiwand.com/en/Nitrous_oxide&quot; rel=&quot;nofollow noreferrer&quot;&gt;nitrous oxide&lt;/a&gt; is 298 times as high as that of carbon dioxide, and that it makes 7.9% of the humans caused greenhouse gases:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fQ0JG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fQ0JG.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given these numbers nitrous oxide seems to contribute roughly 30 times more heavily to climate change than carbon dioxide does.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is nevertheless carbon dioxide the gold standard of greenhouse gases and humans caused climate change?&lt;/p&gt;&#xA;" OwnerUserId="17431" LastEditorUserId="543" LastEditDate="2021-06-25T07:04:39.060" LastActivityDate="2021-06-25T15:36:18.980" Title="Why is carbon dioxide a more important greenhouse gas than nitrous oxide?" Tags="|climate-change|carbon|ecology|nitrogen|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17528" PostTypeId="2" ParentId="96" CreationDate="2019-07-22T11:34:39.507" Score="4" Body="&lt;p&gt;Oceans &lt;em&gt;did&lt;/em&gt; form on other rocky planets - at least Venus and Mars, and moreover, many moons of Jupiter and Saturn as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem is that of the two other terrestrial &quot;&lt;em&gt;uberplanets&lt;/em&gt;&quot; who &lt;em&gt;had&lt;/em&gt; oceans - i.e. the aforementioned Venus and Mars - they lost them, but in rather different ways. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;On Venus, what happened appears to have been that, synthesizing the best theories and evidence so far, as the Sun steadily grew hotter as a result of the natural main-sequence stellar evolution, the planet essentially left the habitable zone. The oceans evaporated and were lost to space. The way that works is that as the planet heats up, the water vapor content in the atmosphere increases, and some of that vapor rises to the top of the atmosphere. At the top, the UV flux begins to break apart (photodissociation) the water molecules, releasing the hydrogen, which then easily escapes as its gravitoionization energy is very low (for Venus, with an escape velocity of 10.36 km/s, it is similar to Earth - stripping one &lt;span class=&quot;math-container&quot;&gt;$\mathrm{H}_2$&lt;/span&gt; molecule, a mass of ~3.4 yg, costs 0.18 aJ or 1.1 eV, which can easily be supplied by photons, stellar wind, or other factors. Stripping nascent [monoatomic] hydrogen, if such could happen without molecularization, takes half this.). The end result is an oxygen-rich atmosphere (nearly pure oxygen) at very high pressure, though chemical reactions with the rock below may strip some of this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But as you may note, the current atmosphere is mostly carbon dioxide, with a very high surface temperature, and thus while the above is fairly plausible, one must wonder how this atmosphere obtained. Well, here's the thing. Much like Earth, Venus likely had plate tectonics early in its history when it had oceans. Ocean water seems to be a necessary component of plate tectonic activity on planets at least around the size of Earth, acting as a sort of &quot;lubricant&quot;, and without it, plate tectonics cannot operate. Hence, once the water evaporated from Venus, any tectonics it had would have stopped.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cessation of plate tectonics, while it may not seem like much to the uninitiate (so what? The continents stop moving, and you stop getting earthquakes?), is actually &lt;em&gt;catastrophic&lt;/em&gt; for this kind of planet. You see, plate tectonics does more than just move continents, mountains, and earthquakes. What it most &lt;em&gt;crucially&lt;/em&gt; does is to serve as a sort of &quot;release valve&quot; for the heat that is being generated inside the planet as a result of the decay of primordial radionuclides mixed with the mantle rocks (mostly &lt;span class=&quot;math-container&quot;&gt;$^{238}\mathrm{U}$&lt;/span&gt;). This is because that, at spreading zones, hot mantle material oozes out (Iceland is a good Earthbound example of where this process happens to just come above water and can be seen with the naked eye - youtube it if you're too poor to travel), and at subduction zones, volcanoes are created, like in the Pacific Ring of Fire on Earth. The released material transfers the heat to the atmosphere and thus ultimately it gets radiated into space, hence shedding the internal heat. Without this process, that heat is shed far less efficiently - essentially only by conduction through the ground, which is terrible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a result, once you lose tectonics, the radioactive heat begins to build within the interior, and the mantle temperature starts to rise considerably. And when that starts, eventually, something has to give. And what &quot;gives&quot; is not quite well-understood but it seems to be either that tectonics restarts for a &quot;short&quot; time &quot;with a vengeance&quot;, or that there commence widespread basaltic flood eruptions, or some combination of the two. In any case, the result is a rapid - on a geological scale of course, actually about 100 million years - &quot;global resurfacing event&quot; resulting in either or a combination of total subduction/reemplacement of the old crust (hence that is a considerably faster rate of tectonic motion than on Earth - to recycle all its crust over 100 Myr would take plate motion on the order of 20 cm/yr, where the fastest plate movement [India] in recent time was only around 4-6 cm/yr), or its progressive burial in flows similar to those from the Siberian Traps, likely from multiple vent sources, extending over such a long enough period as to cover all low-lying areas at least. In both cases there occurs the widespread release of volcanic gases which chiefly includes carbon dioxide, and that quickly converts the atmosphere to a &quot;runaway greenhouse&quot; state like we see on the planet today. The last GRE on Venus was finished at about 500 Ma, and there may have been more before that until the time when it last had oceans, and it is possible that the current thickness was the result of such a chain of episodes instead of just one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The oceans on Mars, on the other hand, seem to have suffered a rather quieter demise. In this case, it seems the chief problem was the planet was simply too small, and the cause was not the result of external changes in the form of those in the Sun, but rather internal ones. As a result of its lack of size and hence of mass, there was both less primordial heat within the core and a smaller radionuclide load to maintain the internal temperature. The interior would have cooled to the point its iron inner core froze completely, and that shut down the planetary magnetic dynamo, which we know existed in the past thanks to there still being today small areas of &quot;fossilized&quot; magnetization in the crust due to rich concentrations of magnetizeable iron minerals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And this is a problem because the magnetic field on a terrestrial planet serves the purpose of deflecting the solar wind away from the atmosphere. Without it, the wind directly strikes the atmosphere and begins to &quot;sputter&quot;, or blow, it away. Mars thus lost its atmosphere in a comet tail-like effect, and with that also went the oceans thanks to the resulting pressure drop. What was left was the small amount of heavy (and hence hard to remove) carbon dioxide. No runaway greenhouse was produced because the thermal situation in the interior was just the opposite - it wasn't overheating, but rather, it was cooling down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Generally, as long as the material from which you form planets - i.e. the star's proplyd - has sizeable quantities of water, as typically is the case, the planets will form oceans thanks to the chemical differentiation process leading to accumulation of a surface reservoir. Indeed, in many cases, they can form much &lt;em&gt;more&lt;/em&gt; ocean as we've seen by observation of extrasolar planetary systems with planets that could have &quot;ocean&quot; layers hundreds of km thick (technically, this would only be liquid &lt;em&gt;ocean&lt;/em&gt; proper down to about 100 km or so - at that point, the pressure becomes high enough [though the precise depth depends on the local gravity] to freeze the water by compression [pressure approx 1 GPa, for comparison, the Marianas on Earth, at 10 km depth is around 100 MPa], and the rest of the layer below that point is various high-pressure phases of ice) hence no bare land. It all depends on the water content of the material that forms it, and that is quite variable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(One could, actually, consider certain moons of Jupiter and Saturn as actually Solar System examples of this kind of planetary composition, just at a much-reduced size as the extrasolar examples are north of one Earth mass (&lt;span class=&quot;math-container&quot;&gt;$6000\ \mathrm{Yg}$&lt;/span&gt;).)&lt;/p&gt;&#xA;" OwnerUserId="7283" LastActivityDate="2019-07-22T11:34:39.507" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="17529" PostTypeId="2" ParentId="17526" CreationDate="2019-07-22T11:34:50.997" Score="2" Body="&lt;p&gt;There isn't enough nitrous oxide in the atmosphere to make a major contribution to global warming, which in some ways is a pity, because we'd all bee in a much jollier mood if there was (N2O is sometimes known as laughing gas). It also depletes the ozone layer if it gets up that high, though depleting ozone at ground level, where it is harmful, is a good thing. Compared to N2O, there are vast quantities of CO2 in the atmosphere, enough to create millions of tons of wood and other plant materials every year. The whereabouts of N2O in the atmosphere, whether it is high up or low down, probably has some bearing on the matter.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-22T11:34:50.997" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17530" PostTypeId="1" CreationDate="2019-07-22T12:07:30.513" Score="33" ViewCount="19375" Body="&lt;p&gt;This is something that just occurred to me. If heavier elements sink, then how can the entire ocean be salty? Shouldn't the 'salt', because of its density, all sink to the bottom of the ocean? In theory, only the deepest parts of the ocean should be salty, while the top of the ocean is not. Yet, the only water in the world that isn't salty comes from rain and rivers. How can this be?&lt;/p&gt;&#xA;" OwnerDisplayName="user17432" LastActivityDate="2022-12-19T20:27:40.673" Title="Why does the salt in the oceans not sink to the bottom?" Tags="|oceanography|water|" AnswerCount="11" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17531" PostTypeId="2" ParentId="17530" CreationDate="2019-07-22T12:56:10.320" Score="39" Body="&lt;p&gt;When dissolved in water, salt breaks up into sodium and chlorine ions, which combine with water molecules so they cannot easily sink. However, there is a tendency for streams of fresh water to float on salt water and rise to the top. This caused problems for British submarines in the Dardanelles Straits during WW1. Moving from almost fresh water to the denser salt water, they suddenly became more buoyant and rose involuntarily to the surface, making them visible to Turkish gunners on the shore. There are also parts of the ocean where there are pools of very salty water lying on the bottom in such a way as to clearly show the pool to any diver who happens to see it, as though it were a pool on land, so in some circumstances very salty water can sink.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-22T12:56:10.320" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17532" PostTypeId="2" ParentId="17530" CreationDate="2019-07-22T13:33:08.160" Score="8" Body="&lt;p&gt;Turbulence, because seawater is, almost, always on the move saltier water is mixed with fresher by wave action and, to a lesser extent in surface waters, by &lt;a href=&quot;https://en.wikipedia.org/wiki/Brownian_motion&quot; rel=&quot;noreferrer&quot;&gt;Brownian motion&lt;/a&gt;. In &lt;a href=&quot;https://en.wikipedia.org/wiki/Fiordland&quot; rel=&quot;noreferrer&quot;&gt;Fjordland&lt;/a&gt; the annual rainfall is so high (up to 8000mm) that there is a permanent freshwater layer several metres thick that you can drink from sitting over the salt water from the Tasman in the sheltered inlets. Even there this layer doesn't have a clear cut boundary but rather a mixing layer where the salt and fresh water exchange particles and homogenise over time. In bodies of water that don't experience regular circulation stagnation and anoxia set in over time but &lt;a href=&quot;https://en.wikipedia.org/wiki/Solution&quot; rel=&quot;noreferrer&quot;&gt;chemical solution&lt;/a&gt; of a number of &lt;a href=&quot;https://en.wikipedia.org/wiki/Solvation&quot; rel=&quot;noreferrer&quot;&gt;dissolved&lt;/a&gt; salts still occurs.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2019-07-22T13:33:08.160" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17533" PostTypeId="1" CreationDate="2019-07-22T13:55:53.877" Score="3" ViewCount="71" Body="&lt;p&gt;We have taken the measurments of temperature, humidity, net radiation and pressure in our lab so we can calculate the potential reference EvapoTranspiration. So to find out the potential reference ET we have the minimum temperature and maximum temperature of each half an hour. same for humidity. My question is to find out ET per day, should I take the mean of minimums or the minimum of all? I have the same question for maximums. per day and per month.&#xA;Thanks.&lt;/p&gt;&#xA;" OwnerUserId="17434" LastActivityDate="2019-07-22T13:55:53.877" Title="is it better to take minimum measure of all measures or the mean of minimum measures as a minimum measure" Tags="|climate-change|evaporation|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17534" PostTypeId="1" CreationDate="2019-07-22T18:54:15.667" Score="1" ViewCount="121" Body="&lt;p&gt;I just read this article by scientist who propose making giant snow machines to basically move the eroding ice shelf further inland. It’s been described as pretty much cost prohibitive (despite saving the coasts from rising water levels??) and would be on the same level of effort as putting a base on the moon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here’s the link: &lt;a href=&quot;https://advances.sciencemag.org/content/5/7/eaaw4132&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://advances.sciencemag.org/content/5/7/eaaw4132&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So instead of doing that, why not drill a large hole straight down into one end of a section of the ice shelf (closest to land but still a thick part of ice) and insert a large tap and then use large fresnel lens to melt a slope in the ice and funnel the melted ice into the hole and out the spout to be diverted further inland which would eventually refreeze later?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You would just have to melt the section of the ice shelf at a graded slope so that gravity does all the work. If you look at how water towers work and then consider the thickness of the ice shelf, you could calculate amount of water pressure and will see that it would suffice to move large quantities of water at a very fast pace.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just a thot&lt;/p&gt;&#xA;" OwnerUserId="17435" LastActivityDate="2020-01-19T23:01:35.150" Title="A better way to prevent ice shelf from melting and raising ocean levels?" Tags="|ice-sheets|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17535" PostTypeId="2" ParentId="17534" CreationDate="2019-07-22T19:55:56.330" Score="1" Body="&lt;p&gt;The problem is that &quot;inland&quot; is &lt;em&gt;uphill&lt;/em&gt; from the sea. If you can cause gravity to make water flow uphill, you can solve many more problems than just sea-level rise.&lt;/p&gt;&#xA;" OwnerUserId="13324" LastActivityDate="2019-07-22T19:55:56.330" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17536" PostTypeId="2" ParentId="17534" CreationDate="2019-07-22T21:03:53.823" Score="0" Body="&lt;p&gt;I don't think what you suggest could be done economically. A much better way of reducing sea level would be to siphon the ocean into the numerous low lying areas of the world which are below mean sea level, for example, the Aral sea in Uzbekistan, &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Eyre&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Eyre&lt;/a&gt; (&lt;em&gt;Kati Thanda, indigenous name&lt;/em&gt;)  in Australia, the Fayum Depression in Egypt, and there ore many others.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The place to start would be the Aral sea, which has virtually dried out, creating all sorts of economic problems for the people in the area. Water could be siphoned from the Black Sea into the Caspian Sea, which is also well below mean sea level. From there it could be siphoned into the Aral which is even further below mean sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This would restore the waterborne transport system of the Aral, restore the fisheries, put an end to the windblown salt which is contaminating agricultural land in the area, and probably alter the climate for the better, as well as making a start on reducing mean sea level. You wouldn't even need pumps, because the siphon principle that water always finds its own level is enough to move the water. When we have refilled the Aral, we could start on some other low lying land area, perhaps Lake Eyre.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="2470" LastEditDate="2019-07-23T04:12:00.957" LastActivityDate="2019-07-23T04:12:00.957" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17537" PostTypeId="1" CreationDate="2019-07-22T21:15:07.573" Score="1" ViewCount="2666" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/SJtoQ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that Strike and dip refer to the orientation or attitude of a geologic feature. The strike line of a bed, fault, or other planar feature, is a line representing the intersection of that feature with a horizontal plane. On a geologic map, this is represented with a short straight line segment oriented parallel to the strike line. &#xA;The dip gives the steepest angle of descent of a tilted bed or feature relative to a horizontal plane, and is given by the number (0°-90°) as well as a letter (N,S,E,W) with rough direction in which the bed is dipping downwards. &#xA;However, I am completely clueless about how to solve it on a geologic map as in the example given above&lt;/p&gt;&#xA;" OwnerUserId="17437" LastEditorUserId="17437" LastEditDate="2019-07-22T23:52:11.177" LastActivityDate="2019-07-22T23:52:11.177" Title="How to draw a strike and dip on a geologic map?" Tags="|homework|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17538" PostTypeId="2" ParentId="17530" CreationDate="2019-07-23T02:01:11.270" Score="6" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Saltier water has higher mass density, so the gravitational energy can be lowered that way. The concentration differences go up until the free-energy of creating that big a concentration difference balances the gravitational energy change.&lt;br /&gt;&#xA;&lt;a href=&quot;https://van.physics.illinois.edu/qa/listing.php?id=24631&amp;amp;t=salt-concentration-vs.-water-depth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Department of Physics, University of Illinois at Urbana-Champaign&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Making some simplifying assumptions, they find:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;the equilibrium concentration goes up exponentially with depth, by a factor of e for each 10 km or so.&lt;br /&gt;&#xA;&lt;strong&gt;The actual oceans are stirred by currents, so this equilibrium concentration difference isn't present in them.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Basically they saying that it takes energy to separate a homogeneous solution into parts which are more or less concentrated (and hence more or less dense). Taking into account the gravitational energy, it follows that the least energy state of a column of water is saltier at the bottom.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2020-10-28T02:48:12.063" LastActivityDate="2020-10-28T02:48:12.063" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="17539" PostTypeId="2" ParentId="17530" CreationDate="2019-07-23T09:56:04.567" Score="30" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Why does the salt in the oceans not sink to the bottom?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Because there isn't any &quot;salt&quot;, &lt;em&gt;per se&lt;/em&gt;, in the ocean. Salt, as the compound sodium chloride (NaCl) does not exist as a solid in the ocean. It is dissolved into sodium and chloride ions (charged atoms) that exist within the ocean as a homogenous &lt;a href=&quot;https://en.wikipedia.org/wiki/Phase_(matter)&quot; rel=&quot;noreferrer&quot;&gt;phase&lt;/a&gt; (that is, a &quot;thing&quot;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, water with sodium chloride dissolved in it is indeed denser than pure water, because after all, sodium and chlorine atoms are denser than atoms of hydrogen and oxygen. This leads to an interesting phenomenon: you can have layers of more-salty water and less-salty water that do indeed rise and sink. There are several YouTube videos that demonstrate this very well. For example this video shows dyed salty and fresh water, separated by a barrier:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UUXeK.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UUXeK.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and then when the barrier is released, the salty water sinks down:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/N7tdH.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/N7tdH.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://youtu.be/7fqOtgG6vik&quot; rel=&quot;noreferrer&quot;&gt;Source&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some other videos: &lt;a href=&quot;https://youtu.be/moHj5mhOXrk&quot; rel=&quot;noreferrer&quot;&gt;one&lt;/a&gt; and &lt;a href=&quot;https://youtu.be/_Ohd4JGZ_gA&quot; rel=&quot;noreferrer&quot;&gt;two&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This phenomenon is extremely important for planet-scale ocean circulation, and has strong influence on our climate.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2019-07-24T12:07:27.590" LastActivityDate="2019-07-24T12:07:27.590" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="17540" PostTypeId="2" ParentId="17526" CreationDate="2019-07-23T10:02:43.430" Score="3" Body="&lt;p&gt;Two things to think about:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nitrous oxide is extremely scarce in the atmosphere, less than 1 ppm. Compare with carbon dioxide that (unfortunately) is now greater than 400 ppm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also consider the &lt;a href=&quot;http://chartsbin.com/view/2407&quot; rel=&quot;nofollow noreferrer&quot;&gt;lifetime of the gases in the atmosphere&lt;/a&gt;: nitrous oxide has a much shorter lifetime than carbon dioxide. If we'd stop emitting greenhouse gases now, nitrous oxide would be gone much quicker than carbon dioxide.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-07-23T10:02:43.430" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17541" PostTypeId="1" CreationDate="2019-07-23T10:29:00.687" Score="2" ViewCount="223" Body="&lt;p&gt;Nowadays, everyone talks about it: climate change, and more importantly, how to stop it from happening. Although there's a lot of debate around the topic, the conscensus is that by inventing a way of generating clean energy, we can slow down (and maybe even reverse) the effects global warming has on the planet. Using energy that was created without burning millions of years worth of stored carbon, we can not only power our everyday lives, but also capture the carbon we've been blowing into our atmosphere using the energy-intensive process of carbon capture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But there are still some problems. Currently, photovoltaic cells are pretty much useless during winter when it comes to fueling the homes of millions (at least where I live). We want to warm our homes, but there's not enough clean energy during those months, so we fall back on nuclear.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wouldn't it therefore be better to have a small rise in global temperature? I mean, a higher temperature means you don't have to warm your home during winter (as much). During summer, you can use the extra energy generated by the photovoltaic cells to power airconditioners in order to cool buildings and (maybe) use some excess energy to stop the snowball effect that those higher temperatures would have on the climate and keep it at a constant level. Even though cooling requires more energy than heating, might it break even?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't have the knowledge nor the means to calculate if this is the case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that climate change is a thing and that it's really, really bad. I'm not a guy that doesn't believe the effects it has on our surroundings. I just don't have the means to investigate this idea, that's why I ask you: will the rise in temperature have a positive effect on our energy production and the ability to satisfy energy demand?&lt;/p&gt;&#xA;" OwnerUserId="17439" LastActivityDate="2019-07-30T05:21:38.490" Title="Isn't a warmer climate better for energy generation?" Tags="|climate-change|" AnswerCount="4" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17542" PostTypeId="2" ParentId="17541" CreationDate="2019-07-23T12:22:46.893" Score="-7" Body="&lt;p&gt;We are going to get climate change whether we like it or not. Climate change has been happening throughout the last 4 billion years, and it is highly improbable that mankind is suddenly going to stop dead it in its tracks in the 21st century. It can't be denied that human activity is very gradually increasing the amount of CO2 in the atmosphere, but up to a point this process is self regulating. The higher the concentration of CO2, the more vigorously plants will grow and extract it again, but this self regulation could be overwhelmed if the amount of CO2 increases too rapidly. The present warming phase began 12,000 years ago, long before human activities contributed to CO2 levels, so there must have been some other cause. It isn't known for sure whether the sun's radiation is constant and never varies. We are now in an interglacial, which if we go by the geological record is due to end in about 5,000 years time, then it's back to the ice ages again. There was a 450 year Little Ice Age between about AD 1350 and AD 1810.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Higher temperatures don't necessarily mean more sunlight for your solar cells, but the prospect of serious climate warming provides an incentive to develop non-polluting sources of energy, of which fusion power is the most promising (yes, I know fusion produces small amounts of radioactive pollutants, but nothing by comparison with fission). I'm a bit puzzled by your snowball effect of higher temperatures. I would have thought a snowball effect would be more likely with lower temperatures.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-23T12:22:46.893" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="17543" PostTypeId="1" CreationDate="2019-07-23T15:33:54.570" Score="3" ViewCount="82" Body="&lt;p&gt;I find many researchers use Machine Learning Techniques and Algorithms to calculate the EvapoTranspiration, while there’s also the Penmann Monteith equation that gives us the result. Does this say we don’t need Penmann equation anymore?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a research samples:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://lahore.comsats.edu.pk/Papers/Abstracts/1210-8586787794296626450.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://lahore.comsats.edu.pk/Papers/Abstracts/1210-8586787794296626450.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.tandfonline.com/doi/pdf/10.1623/hysj.54.5.918&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.tandfonline.com/doi/pdf/10.1623/hysj.54.5.918&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="17434" LastEditorUserId="2470" LastEditDate="2021-10-07T10:39:24.360" LastActivityDate="2021-10-07T10:39:24.360" Title="Why estimate evapotranspiration using machine learning techniques while we can calculate it with Penmann Monteith equation?" Tags="|evaporation|predictability|research|machine-learning|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="17544" PostTypeId="1" AcceptedAnswerId="18372" CreationDate="2019-07-23T18:09:42.787" Score="3" ViewCount="112" Body="&lt;p&gt;I ran a 60 m line intended for surficial seismic refraction. Energization with hammer. 12 (10 hz vertical 5 m spaced) geophones and 5 shots (15 m spaced). Record length 0.5 s. Thanks to a borehole near a strata of man-made gravelly silt (0.40 m) and very soft silty clay (to 5 m) and then clay improves its consistency deeper were identified. My seismic traces seemed to be ok, but at office the principal wave train gives 200 m/s and first arrivals refractions are so weak that they cannot be easily identified. I think the principal train wave shadows them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;My question: What is the meaning of a 200 m/s train wave?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lQI6K.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lQI6K.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17444" LastEditorUserId="11430" LastEditDate="2019-08-10T08:51:52.087" LastActivityDate="2019-11-04T03:34:26.340" Title="Wave train 200 m/s meaning" Tags="|geophysics|seismology|seismic|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17545" PostTypeId="2" ParentId="17507" CreationDate="2019-07-23T20:36:55.300" Score="7" Body="&lt;p&gt;There's nothing inexplicable about that photo.  It's got a few uncommon features, but nothing unknown.  In the image below, I've drastically distorted the brightness curve to make things more obvious:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pZ7Ty.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pZ7Ty.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.atoptics.co.uk/rainbows/primary.htm&quot; rel=&quot;noreferrer&quot;&gt;Primary arc&lt;/a&gt;.  This is the classic &quot;internal reflection&quot; rainbow that you learn about in school.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.atoptics.co.uk/rainbows/sec.htm&quot; rel=&quot;noreferrer&quot;&gt;Secondary arc&lt;/a&gt;.  This one forms when light is reflected twice within a raindrop, broadening the bow and reversing the order of the colors.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.atoptics.co.uk/rainbows/supform.htm&quot; rel=&quot;noreferrer&quot;&gt;Supernumerary arcs&lt;/a&gt;.  These are formed by the wave nature of light: light, even of a single color, spreads out as it passes through a raindrop.  The arcs are interference patterns formed by the spread-out light from many small raindrops, and because of this spreading, they're usually pastel colors rather than the single-frequency colors of the main arcs.  The less variation there is in raindrop size, the sharper the arcs are; these are especially sharp.&lt;/li&gt;&#xA;&lt;li&gt;Supernumerary arcs on the secondary bow.  These are rarely seen, because they're even more sensitive to variations in raindrop size than the primary arc's supernumeraries.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.atoptics.co.uk/rainbows/ord56.htm&quot; rel=&quot;noreferrer&quot;&gt;Possible fifth-order bow&lt;/a&gt;.  This faint green patch is in the right place to be the green stripe from light reflecting five times as it passes through a raindrop.  Fifth-order bows are almost never seen because of how faint they are, and are photographed even less often, so this may just be an image artifact.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.atoptics.co.uk/rainbows/primrays.htm&quot; rel=&quot;noreferrer&quot;&gt;Primary glow&lt;/a&gt;.  Only the light passing through the edges of a raindrop forms the rainbow.  Most of the light passing through the middle just goes straight through to form the &lt;a href=&quot;https://www.atoptics.co.uk/rainbows/ord0.htm&quot; rel=&quot;noreferrer&quot;&gt;zero-order glow&lt;/a&gt; (not pictured), but some reflects back to form a glow in the middle of the rainbow.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.atoptics.co.uk/rainbows/adband.htm&quot; rel=&quot;noreferrer&quot;&gt;Alexander's dark band&lt;/a&gt;.  The light making up the rainbows has to come from somewhere, and this band is where it comes from.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.atoptics.co.uk/rainbows/rflctd.htm&quot; rel=&quot;noreferrer&quot;&gt;Reflected rainbow&lt;/a&gt;.  This isn't a reflection of the primary arc (rainbows aren't real objects, so they don't have reflections), it's the rainbow you'd see if your position had been reflected across the plane of the water.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;All of these have been known to science for quite some time.  The primary arc was the first one to be explained, &lt;a href=&quot;https://en.wikipedia.org/wiki/Rainbow#Scientific_history&quot; rel=&quot;noreferrer&quot;&gt;by Persian astronomers in the 1200s&lt;/a&gt;.  Supernumerary arcs were the last one to be explained, &lt;a href=&quot;https://books.google.com/books?id=7AZGAAAAMAAJ&amp;amp;pg=PA1#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;noreferrer&quot;&gt;by Thomas Young in 1803&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &quot;third rainbow&quot; the BBC is talking about is probably the first few supernumerary arcs of the primary arc.  Supernumerary arcs have the same color ordering as the arc they're attached to, but because the brightness and width of the arcs varies, and because they're usually pastel colors rather than spectral colors, it can give the appearance of a reversed spectrum.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &quot;third rainbow&quot; isn't a &lt;a href=&quot;https://www.atoptics.co.uk/rainbows/twin1.htm&quot; rel=&quot;noreferrer&quot;&gt;twinned rainbow&lt;/a&gt;, because the second arc of a twinned rainbow (caused by two rainstorms at different distances with different raindrop characteristics) wouldn't be concentric with the first arc.&lt;/p&gt;&#xA;" OwnerUserId="2643" LastEditorUserId="2643" LastEditDate="2019-07-23T22:26:53.350" LastActivityDate="2019-07-23T22:26:53.350" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17549" PostTypeId="2" ParentId="17530" CreationDate="2019-07-23T22:08:03.460" Score="2" Body="&lt;p&gt;But it does, but according to each salt's solubility and density. Soluble salts tend to mix into the water and keep suspended. Insoluble salts separate from the solution and creates deposits in the oceanic floor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One famous example was the &quot;de-ironing&quot; of the seas, when iron salts were deposited in the bottom due to the oxigenation of the oceanic water, by the time of the emergence of aerobic, photosynthetic organisms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Great Oxidation Event: &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Oxidation_Event&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Great_Oxidation_Event&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;The oxygen then combined with dissolved iron in Earth's oceans to form insoluble iron oxides, which precipitated out, forming a thin layer on the ocean floor&quot;.&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Banded_iron_formation&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Banded_iron_formation&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17447" LastActivityDate="2019-07-23T22:08:03.460" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17550" PostTypeId="2" ParentId="14993" CreationDate="2019-07-24T04:43:45.570" Score="1" Body="&lt;p&gt;It has been burned.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No acidity etc. needed. If you throw one fist sized granit into a normal campfire (usually around 700 C) and leave it there to burn for some hours, when it cools it will crumble in your hands. As mentioned before &quot;granite is made of crystals of different minerals&quot; in intensive heat/cooling each mineral expands at a different rate and brakes the composition apart.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tested myself many times in practise..&lt;/p&gt;&#xA;" OwnerUserId="17450" LastActivityDate="2019-07-24T04:43:45.570" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17557" PostTypeId="1" CreationDate="2019-07-24T15:55:24.367" Score="1" ViewCount="579" Body="&lt;ol&gt;&#xA;&lt;li&gt;I have an NC file that has global data with a high resolution (about 25 minutes) so a lot of coordinates.&lt;/li&gt;&#xA;&lt;li&gt;I have some measured values of some region with irregularly spaced coordinates.&lt;/li&gt;&#xA;&lt;li&gt;In order to mathematically operate between the two, I am aiming to interpolate the global data to the local irregular grid, instead of the opposite, to minimize the uncertainty.&lt;/li&gt;&#xA;&lt;li&gt;How do I achieve this? I was thinking of Scipy's griddata module but cannot seem to initiate the process. Thanks a lot.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried the following, a little heavy on resources but I think it works.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;from scipy.interpolate import interp2d   &#xA;f = interp2d(longw,latw,Zw)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;where longw,latw,Zw are the world coordinates of the NETCDF file and the 2D variable respectively.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then I applied &lt;code&gt;f(lon,lat)&lt;/code&gt; to all my irregular observations y iteration to interpolate. The lon and lat are the observed coordinates of the local region. &lt;/p&gt;&#xA;" OwnerUserId="17457" LastEditorUserId="17457" LastEditDate="2019-07-25T04:44:15.493" LastActivityDate="2019-07-31T08:58:30.927" Title="Interpolating world data to a local grid in Python" Tags="|meteorology|python|grid-spacing|interpolation|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="17558" PostTypeId="2" ParentId="17541" CreationDate="2019-07-24T18:32:35.793" Score="3" Body="&lt;p&gt;The real problem, of course, is that it's not going to be limited to a small rise in temperature.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, WRT energy generation in particular, most forms of generation become less efficient as temperature increases.  For thermoelectric generation - fossil fuel, nuclear, &amp;amp; geothermal - that's obvious thermodynamics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Photovoltaic cell efficiency also decreases with increasing temperature (e.g. &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S1876610213000829&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/S1876610213000829&lt;/a&gt; ).  The drop in energy production during winter is a product of factors like the shorter day and lower sun angle, not the temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unless I've missed something, that leaves just hydroelectric &amp;amp; wind generation.  AFAIK, they aren't directly affected by temperature.  Changes in weather patterns might produce more or less precipitation and stronger or weaker winds in any particular location, but I don't think the effects are predictable, or necessarily a net increase.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, increased temperature affects the efficiency of power transmission.  Electrical resistance increases with temperature, so an increase in temperature leads to increased transmission losses, and a decrease in the effective capacity of the lines: &lt;a href=&quot;https://iopscience.iop.org/article/10.1088/1748-9326/11/11/114008&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://iopscience.iop.org/article/10.1088/1748-9326/11/11/114008&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1401" LastEditorUserId="1401" LastEditDate="2019-07-24T18:38:11.373" LastActivityDate="2019-07-24T18:38:11.373" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="17559" PostTypeId="2" ParentId="17541" CreationDate="2019-07-24T20:10:48.297" Score="0" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Currently, photovoltaic cells are pretty much useless during winter&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That may be true if you live at a high latitude, but it isn't universally true.&#xA;Fortunately, solar is not our only source of low-carbon electricity, and in many climates, wind farms and wave generators become &lt;em&gt;more&lt;/em&gt; effective in winter.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We want to warm our homes, but there's not enough clean energy during&#xA;  those months&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;[citation needed]&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;so we fall back on nuclear.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Do we?&#xA;There may be some country where this is the case, but it's not common anywhere that I'm familiar with.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Wouldn't it therefore be better to have a small rise in global&#xA;  temperature? I mean, a higher temperature means you don't have to warm&#xA;  your home during winter (as much). During summer, you can use the&#xA;  extra energy generated by the photovoltaic cells to power&#xA;  airconditioners&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A higher temperature means less heating needed and more cooling needed. I don't know how it will balance out globally, or on a per-country (or per-electrical-grid) basis. I think you're hoping that the extra cooling isn't a problem because of getting more power from photovoltaics, but I think you're assuming that higher temperatures mean more sunlight. This isn't necessarily the case.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;will the rise in temperature have a positive effect on our energy&#xA;  production and the ability to satisfy energy demand?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The rise in global average temperature, in itself: I don't know, and I don't know if anybody knows. Different energy sources will be affected differently, and much will depend on regional weather responses to changes in climate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The socio-economic effects of global warming, IMHO, will almost certainly have a net negative effect on our ability to satisfy demand - unless we have a full-on collapse of civilization in some areas and demand crashes.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-07-24T20:10:48.297" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17560" PostTypeId="2" ParentId="17530" CreationDate="2019-07-24T20:14:30.750" Score="11" Body="&lt;p&gt;I'm a regular from the Physics Stack Exchange reporting for duty.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Why this is a serious question&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;This is a bigger question than you might be giving it credit for. The question is ultimately similar to asking why all the air molecules in the atmosphere do not fall to the floor. Your question comes from a very solid principle in physics which could be called the &lt;a href=&quot;https://en.wikipedia.org/wiki/Principle_of_minimum_energy&quot; rel=&quot;noreferrer&quot;&gt;minimum energy principle&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The basic derivation is that if you define the power exerted by a force &lt;span class=&quot;math-container&quot;&gt;$\mathbf F_i$&lt;/span&gt; on a particle with velocity &lt;span class=&quot;math-container&quot;&gt;$\mathbf v$&lt;/span&gt; to be &lt;span class=&quot;math-container&quot;&gt;$$P_i=\mathbf F_i\cdot\mathbf v = |\mathbf F_i|~|\mathbf v|~\cos\theta,$$&lt;/span&gt;then Newton’s law that the sum of forces on a particle &lt;span class=&quot;math-container&quot;&gt;$\sum_i \mathbf F_i = m~\dot{\mathbf v}$&lt;/span&gt; is the mass times the change in velocity per unit time, directly implies that the sum of powers exerted on a particle &lt;span class=&quot;math-container&quot;&gt;$\sum_i P_i = \dot K$&lt;/span&gt; is the change in kinetic energy per unit time. Drag forces exist and they oppose relative motion, so their &lt;span class=&quot;math-container&quot;&gt;$\cos \theta$&lt;/span&gt; is negative and they will decrease kinetic energy, &lt;span class=&quot;math-container&quot;&gt;$\dot K &amp;lt; 0.$&lt;/span&gt; Since energy is a conserved quantity (a “stuff,” if you’d like: if you find more or less of it in a box, then it must have come from somewhere else where there is less or more of it), drag forces eventually rob energy from a system until it ends up at the minimum energy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And it is a very useful principle, for example you can use it to very easily derive the principle of buoyancy and the effective force that must be created by the displaced water to produce that effect; you can't do Newton’s laws easily when there are that many tiny little forces of little water molecules but you can absolutely compare total potential energy when an object is at the bottom of the ocean, the middle, and the top. It fails to describe certain things like static friction (why is my laptop on my desk and not on my floor?!) because it does not tell you &lt;em&gt;how long&lt;/em&gt; such things take and requires an assumption of noise to eventually perturb you out of “local minimums” and such.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But surely the air has had &lt;em&gt;enough time&lt;/em&gt; to fall to the ground if that were &lt;em&gt;what it wanted to do&lt;/em&gt;. The air does not &lt;em&gt;want&lt;/em&gt; to fall to the ground. And we can’t steal our normal solutions for other things like “why don’t clouds fall,” “well what you think of as a cloud is actually more like a waterfall, there is constant movement of water droplets, the water gets a boost upward from heating the air around it as it condenses but it does tend to eventually fall but when it falls beneath a certain flat surface it evaporates again and becomes invisible and so the visible puff is constantly being fed by new water droplet formation and constantly sapped by falling water that becomes invisible…”—no. These are concrete particles that somehow avoid falling to the ground and we have to actually solve the problem.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Fluctuation-Dissipation theorem to the rescue&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The minimum-energy principle describes something that we would call &lt;em&gt;dissipation&lt;/em&gt;, energy leaving one system to end up in another system. These sorts of gates are always bidirectional: energy goes through in both ways. But mostly you don't notice it, and that’s key to how the principle helps us describe things: energy always flows out, it never flows back in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Until, well, it does. Energy of a bouncing ball spreads out among all of the different degrees of freedom of the floor, the air, but if it really goes all the way to 0 and sits perfectly and completely still, very soon the air will bump it and start it jostling and vibrating and moving again—just not moving very much. The same things that allow energy to dissipate must also be contributing constant energy fluctuations that prevent energy from going all the way to 0. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These fluctuations are collectively understood as &lt;em&gt;temperature&lt;/em&gt;. Temperature is technically only defined for a system where all of its degrees of freedom in the ways it can move have come to the same average energy, and it is measured as that average energy. Temperature defines this average energy and the size of these fluctuations. So at room temperature for example we would say that every degree of freedom has 26 meV, 26 &quot;milli-electron-Volts&quot; of energy, or 0.026 of the energy that an electron would have if accelerated by a one volt battery.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So why does the air stay up? It is, basically, because the molecules of the floor are kicking the air molecules with enough energy to hit the upper reaches of the atmosphere. They do not actually go straight there; one air molecule bumps into other air molecules over a very short distance scale: but it transfers that energy and momentum to other particles which transfer that energy and momentum to other particles and in the end the air &quot;prefers&quot; to &quot;hang out&quot; near the ground but the fluctuations cause it to get bumped to an average height given by our temperature. So if you take the mass of nitrogen N&lt;sub&gt;2&lt;/sub&gt; of 28 amu, and the acceleration due to gravity of 9.8 N/kg, you can find out that this 26 meV temperature means that the atmosphere &lt;a href=&quot;https://www.google.com/search?q=26+meV+%2F+%2828+amu+*+9.8+N%2Fkg%29&quot; rel=&quot;noreferrer&quot;&gt;is ~9 km high&lt;/a&gt; on average, which does get you a good chunk into the troposphere where the air starts to thin out dramatically. Actually the theory says that if nothing else were to happen and the random kicks were to just launch a particle up into the atmosphere, it would have a random height sampled according to an exponential probability distribution, &lt;span class=&quot;math-container&quot;&gt;$P(h) \sim e^{-h/(9\text{ km})}$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly why don't the salt molecules fall to the ocean floor? Well, they do, and then they get kicked back up. The water at the ocean floor is saltier. The key difference is whether the salt in question dissolves in water (if it sticks to water better than it sticks to itself) or precipitates in water (it sticks to itself better): larger chunks of a piece of stuff that get bound together will tend to act as big massive chunks and then that thermal energy cannot kick it as high.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the general idea of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Fluctuation-dissipation_theorem&quot; rel=&quot;noreferrer&quot;&gt;fluctuation-dissipation theorem&lt;/a&gt;, which states that fluctuation and dissipation (under some extremely broad assumptions called “detailed balance”) &lt;em&gt;always&lt;/em&gt; go hand-in-hand. Anything which can absorb light (dissipation) must radiate light into space (blackbody radiation, a sort of fluctuation). Every electrical resistor is also a noise source (Johnson noise). If energy can flow out of a system into some environment, then it will only flow out until they have the same average energy levels, and if you try to go lower, energy fluctuations from the environment flow back into the system. &lt;/p&gt;&#xA;" OwnerUserId="7635" LastEditorUserId="7635" LastEditDate="2019-07-24T20:38:48.233" LastActivityDate="2019-07-24T20:38:48.233" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17561" PostTypeId="1" AcceptedAnswerId="17562" CreationDate="2019-07-24T22:32:32.557" Score="2" ViewCount="651" Body="&lt;p&gt;Every two hundred thousand years or so the magnetic poles flip. Obviously it is not life ending but how would our weather change? How long does the transition take? Is there a map or model to show where the warmer areas would be effected from the loss of the mesosphere during transition?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nasa.gov/topics/earth/features/2012-poleReversal.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nasa.gov/topics/earth/features/2012-poleReversal.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2019-08-03T20:46:41.497" LastActivityDate="2019-08-05T12:59:21.093" Title="How would our weather change in the event of a magnetic pole shift?" Tags="|atmosphere|geomagnetism|mapping|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17562" PostTypeId="2" ParentId="17561" CreationDate="2019-07-24T23:09:24.870" Score="0" Body="&lt;p&gt;Magnetic reversals are very random and unpredictable,but average about one every 260,000 years. We could have the next at any time,but as I say, they are unpredictable. So faras is known,they don't affect the weather,but they are very useful to geologists because they make tiny magnetic crystals in solidifying volcanic rock line up with the Earth's magnetic field. Thus,millions of years later, geologists can tell how the rock was lined up with the field when it was formed and can see for themselves how the alignment has changed in the intervening timespan. That gives them an insight into continental drift and other crustal movements. It is particularly useful in the study of sea floor spreading.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-24T23:09:24.870" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17563" PostTypeId="2" ParentId="15669" CreationDate="2019-07-25T01:50:56.473" Score="3" Body="&lt;p&gt;Most plastics are made from the already-sunk carbon of crude oil or natural gas, and as a result, can be at best carbon neutral.  However, &lt;a href=&quot;https://en.wikipedia.org/wiki/Bioplastic&quot; rel=&quot;nofollow noreferrer&quot;&gt;bioplastics&lt;/a&gt; such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Cellulose_acetate&quot; rel=&quot;nofollow noreferrer&quot;&gt;cellulose acetate&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Polylactic_acid&quot; rel=&quot;nofollow noreferrer&quot;&gt;polylactic acid&lt;/a&gt; are derived from plant sources; the carbon here comes from the atmosphere, and they can theoretically act as carbon sinks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, even if we switched all our plastic use to bioplastic, and disposed of it in ways that kept it from decomposing, there's not enough of it to be a useful carbon sink.  There are about 1000 billion tons of carbon dioxide in the air above prehistoric levels; humans have produced only about 8 billion tons of plastic in the past century.&lt;/p&gt;&#xA;" OwnerUserId="2643" LastActivityDate="2019-07-25T01:50:56.473" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17565" PostTypeId="1" AcceptedAnswerId="17570" CreationDate="2019-07-25T09:49:10.473" Score="2" ViewCount="89" Body="&lt;p&gt;I have a list of single point values that I want to insert into a grid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;point_values = [1, 4, 5, ...]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;point_lats = [-12.101, -12.1023, -12.1031, ...]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;point_lons = [155.511, 155.520, 155.533, ...]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;the grid latitudes and longitudes are currently in 2d arrays of 2030 x 1350&lt;/p&gt;&#xA;&#xA;&lt;p&gt;latitudes = array of shape 2030 x 1350 of latitudes&lt;/p&gt;&#xA;&#xA;&lt;p&gt;longitudes = array of shape 2030 x 1350 of longitudes&lt;/p&gt;&#xA;&#xA;&lt;p&gt;how could I insert the points into the 2D grid if a point falls within the grid boundaries?&lt;/p&gt;&#xA;" OwnerUserId="17464" LastActivityDate="2019-07-25T15:02:10.717" Title="Insert points into a 2d grid" Tags="|satellites|python|modis|" AnswerCount="1" CommentCount="3" ClosedDate="2019-07-26T21:43:00.550" ContentLicense="CC BY-SA 4.0" />
  <row Id="17567" PostTypeId="1" AcceptedAnswerId="17569" CreationDate="2019-07-25T12:10:25.977" Score="6" ViewCount="1151" Body="&lt;p&gt;Water finds it way to the lowest point because of gravity. &#xA;So if we dig a mine or something same, then how we take ground water in account, so that it doesn't fill in.&lt;/p&gt;&#xA;" OwnerUserId="17468" LastActivityDate="2021-07-22T17:12:28.700" Title="Ground water is almost every where, then how do mines and other holes are digged so that ground water doesn't drain into it" Tags="|water|groundwater|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17568" PostTypeId="2" ParentId="17530" CreationDate="2019-07-25T12:59:24.787" Score="1" Body="&lt;p&gt;And then there is the saturation issue. Salt can be dissolved in water to a certain degree only. Once that degree is exceeded the salt begins to fall out and sink to the ground. If I remember well the limit for water is something like 35g per litre (depending on the temperature)&lt;/p&gt;&#xA;" OwnerUserId="17469" LastActivityDate="2019-07-25T12:59:24.787" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17569" PostTypeId="2" ParentId="17567" CreationDate="2019-07-25T13:38:26.043" Score="15" Body="&lt;p&gt;We pump it out. Open &lt;em&gt;and&lt;/em&gt; closed pit mines usually have &lt;a href=&quot;https://www.scribd.com/document/56831086/Chapter-3-Mine-Pumps&quot; rel=&quot;noreferrer&quot;&gt;pumping installations&lt;/a&gt; to get the water out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Look up &lt;a href=&quot;https://en.wikipedia.org/wiki/Mine_dewatering&quot; rel=&quot;noreferrer&quot;&gt;Mine dewatering on Wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There have also been numerous accidents in the past where mines were flooded (YouTube: &lt;a href=&quot;https://www.youtube.com/watch?v=19tHroU26yA&quot; rel=&quot;noreferrer&quot;&gt;Turkey mining accident: 18 workers trapped after underground water floods mine&lt;/a&gt;), and when left alone many abandoned mines &lt;a href=&quot;https://en.wikipedia.org/wiki/Flooded_mines&quot; rel=&quot;noreferrer&quot;&gt;will fill up&lt;/a&gt; with (ground) water.&lt;br /&gt;&#xA;Sometimes these are nice &lt;a href=&quot;https://www.gue.com/cave-diving-flooded-mine-central-germany&quot; rel=&quot;noreferrer&quot;&gt;diving objects&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or (as Trond Hansen &lt;a href=&quot;https://earthscience.stackexchange.com/questions/17567/ground-water-is-almost-every-where-then-how-do-mines-and-other-holes-are-digged/17569#comment37722_17567&quot;&gt;commented&lt;/a&gt;) we try to prevent it from coming in in the first place, by using cement, grout or bulkheads to 'plug the holes'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are &lt;em&gt;really&lt;/em&gt; interested:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://books.google.nl/books?id=K7jxCAAAQBAJ&amp;amp;pg=PA268&amp;amp;lpg=PA268&amp;amp;dq=preventing+mine+drainage+-acid&amp;amp;source=bl&amp;amp;ots=upAVxEshdP&amp;amp;sig=ACfU3U0OqfMFDwd3db__IUxk2hWi0yO9iw&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=2ahUKEwjD1JeJmtDjAhUBbFAKHSJkC6MQ6AEwDXoECAkQAQ#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;noreferrer&quot;&gt;Mine Water: Hydrology, Pollution, Remediation&lt;/a&gt; by P.L. Younger, S.A. Banwart, R.S. Hedin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://pdfs.semanticscholar.org/ed03/ffbe86a40e374eb64a18dd5d2ae50e0eceb2.pdf&quot; rel=&quot;noreferrer&quot;&gt;Design of Water Holding Bulkheads for CoalMines&lt;/a&gt; by V.S. Mutton and A.M. Rememnikov&lt;/p&gt;&#xA;" OwnerUserId="595" LastEditorUserId="595" LastEditDate="2019-07-25T13:52:26.240" LastActivityDate="2019-07-25T13:52:26.240" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17570" PostTypeId="2" ParentId="17565" CreationDate="2019-07-25T15:02:10.717" Score="1" Body="&lt;p&gt;Technically, this is a mathematical modelling problem. You just happen to be using earth science data - satellite LIDAR readings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ore reserve geologists constantly deal with this, but in three dimensions when they are required to create a block models of a geological deposit from drill hole data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Scientific fields that use 2D data would include: forestry, meteorology and ground contamination studies looking into pollution effects of smelters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Methods you need to consider are &lt;a href=&quot;https://gisgeography.com/inverse-distance-weighting-idw-interpolation/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Inverse Distance Weighting&lt;/a&gt; and possibly &lt;a href=&quot;https://en.wikipedia.org/wiki/Variogram&quot; rel=&quot;nofollow noreferrer&quot;&gt;variography&lt;/a&gt; and &lt;a href=&quot;https://desktop.arcgis.com/en/arcmap/10.3/tools/3d-analyst-toolbox/how-kriging-works.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;kriging&lt;/a&gt;. Variography and kriging are elements of &lt;a href=&quot;https://pro.arcgis.com/en/pro-app/help/analysis/geostatistical-analyst/what-is-geostatistics-.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;geostatistics&lt;/a&gt;, also known as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Regionalized_variable_theory&quot; rel=&quot;nofollow noreferrer&quot;&gt;Theory of Regionalized Variables&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With inverse distance weighting, the distance variable is usually raised to a power n, i.e. &lt;span class=&quot;math-container&quot;&gt;${1/d^n}$&lt;/span&gt;. Choosing the appropriate value of &lt;span class=&quot;math-container&quot;&gt;$n$&lt;/span&gt; is the tricky part. When geologists used inverse distance weighting, prior to primary using geostatistics, typically the value of &lt;span class=&quot;math-container&quot;&gt;$n$&lt;/span&gt; used was 2, but values between 1 and 3 have been used for different deposits.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given that you are using two dimension data, you may need to use &lt;a href=&quot;https://en.wikipedia.org/wiki/Geographic_information_system&quot; rel=&quot;nofollow noreferrer&quot;&gt;GIS&lt;/a&gt; software or other modelling software that offers grid interpolation methods, such as I have mentioned to achieve what you want.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-07-25T15:02:10.717" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17574" PostTypeId="1" CreationDate="2019-07-26T15:22:55.083" Score="5" ViewCount="226" Body="&lt;p&gt;&lt;em&gt;A version of this question was posted in Chemistry SE and Worldbuilding SE but I've been told it wasn't appropriate to either SE. I was told to give this SE a chance. If you think it doesn't belong on this SE please let me know how to appropriately edit or otherwise another SE to try.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Note: This problem comes from my interest in exoplanet sciences but is applicable to earth sciences.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Something that's unclear to me is the exact relationship between gases within an atmosphere and the concentration of those gases within the bodies of water under that atmosphere (like an ocean).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, the solubility of &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; at &lt;span class=&quot;math-container&quot;&gt;$298K$&lt;/span&gt; and 1 bar of atmospheric pressure is ≈ 1.496 g/L in water. My understanding is that number indicates how much &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; can be dissolved within water before the water is saturated with &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; and won't accept any more. However this doesn't tell me what the concentration of &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; &lt;em&gt;would be&lt;/em&gt; under given conditions, it just sets a maximum cap. So 1.496 g/L of &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; &lt;em&gt;might&lt;/em&gt; be dissolved in water, but it could be much much less. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Key Question:&lt;/strong&gt; What are the calculations I need to go through to figure out the amount (total and ratios) of gases in both a planet's oceans and atmosphere assuming I know either:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The total amount of gases within the ocean/atmosphere system, or...&lt;/li&gt;&#xA;&lt;li&gt;The amount of gases present in the atmosphere but not the corresponding amount present in the waters.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;I want to be able to figure out &lt;em&gt;all&lt;/em&gt; the ratios of gases within an atmosphere and dissolved in a planet's waters. Ball-parking is fine if that's the best I can do.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know this is probably a very complex topic, so if it's helpful you could look at the idealized  earth situation I've outlined (below) and rift off those numbers. Not necessary, but there if you need it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could also take the approach of looking at two gases with very different solubility in water, like &lt;span class=&quot;math-container&quot;&gt;$CH_4$&lt;/span&gt; than &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; and look at what would happen to the ratios if there was a heck of a lot more of the less-soluble gas (Methane in this case) in the system than the more soluble gas. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Whatever approach you take, I'd appreciate any insight you can provide. What I really want to learn is both general principles as well as how to establish those principles in actual calculations.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Scenario: If useful refer to these numbers&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assume uniform temperatures at water surface. Assume no minerals dissolved in water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;SURFACE &lt;em&gt;(Idealized Earth)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Total Surface Area: 510 million &lt;span class=&quot;math-container&quot;&gt;$km^2$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;Water Surface Area: 361 million &lt;span class=&quot;math-container&quot;&gt;$km^2$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$15C$&lt;/span&gt; Uniform Surface Temperature&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;ATMOSPHERE &lt;em&gt;(Idealized Earth)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;By Volume: 79% Nitrogen, 20.95% Oxygen, 0.049% Carbon Dioxide, 0.001% Methane&lt;/li&gt;&#xA;&lt;li&gt;Surface Pressure: &lt;span class=&quot;math-container&quot;&gt;$1$&lt;/span&gt;bar&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;OCEAN &lt;em&gt;(Idealized Earth)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Water Ocean (&lt;em&gt;What should be the corresponding dissolved gases?&lt;/em&gt;)&lt;/li&gt;&#xA;&lt;li&gt;Volume: &lt;span class=&quot;math-container&quot;&gt;$1.4$&lt;/span&gt; billion &lt;span class=&quot;math-container&quot;&gt;$km^3$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Bonus: What would change if we lowered/increased atmospheric pressure and/or lowered/raised temperature?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="17481" LastActivityDate="2021-04-17T21:51:57.613" Title="Relationship Between Ratio of Atmospheric Gases and Ocean Gases" Tags="|atmosphere|geophysics|oceanography|geochemistry|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17576" PostTypeId="2" ParentId="17574" CreationDate="2019-07-27T07:59:10.833" Score="0" Body="&lt;p&gt;This is a very complex question, for reasons I shall explain. Firstly. we need to establish what gases there are in the atmosphere before we worry about how much is dissolved in the ocean. Argon deserves a mention at 1 percent, and there are a few other gases in trace amounts, some of them more abundant than methane, some less, but as, like neon, they are only present in trace amounts, we can ignore them. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The oxygen content of the ocean is very important, because almost all marine life except for plants depends on it, but where does it come from? Only some of it is absorbed from the atmosphere, the rest is produced in situ by phytoplankton, blue-green bacteria, algae and sea grass etc. It is just as well that CO2 readily dissolves in water, because all marine photosynthetic life depends on it, though as you say, there are barely more than trace amounts. This breaking down of CO2 and production of oxygen in the ocean is extremely important from many points of view, including climate warming. More CO2 is disposed of by marine plant life than by all the world's rain forests.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The amount of free methane in the ocean is negligible, but the ocean nevertheless contains fairly large amounts in the form of methane clathrates. This is a sort of methane ice, where methane has combined with water at very cold temperatures, and it lies on the sea bed, mostly in deep water where the temperature is about 5 C even in the tropics. Clathrates are also found in the arctic tundra, and climate change fanatics are worried about the prospect of it thawing out.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-27T07:59:10.833" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17584" PostTypeId="1" CreationDate="2019-07-28T07:57:42.150" Score="1" ViewCount="96" Body="&lt;p&gt;In a letter by Charles Darwin to Asa Gray, introducing to him an abstract about what would Origin of Species, he talked about migration of different forms during the glacial epoch, and the reason why you could find European forms in the tropics. He then said:&#xA;From mammalia and shallow sea, I believe&#xA;Japan to have been joined to main land of China within no&#xA;remote period ; and then the migration north and south before,&#xA;during, and after the Glacial epoch would act on Japan,&#xA;as on the corresponding latitude of China and the United&#xA;States.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I wonder which sea he meant by &quot;shallow sea&quot;, and why could this be reason to think that Japan and China were joined?&lt;/p&gt;&#xA;" OwnerUserId="17495" LastActivityDate="2019-07-28T13:48:20.867" Title="Darwin theory about Japan and China" Tags="|paleontology|glaciation|evolution|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17586" PostTypeId="2" ParentId="17584" CreationDate="2019-07-28T13:48:20.867" Score="2" Body="&lt;p&gt;At the northern and southern ends of the Sea of Japan, there are only short stretches of very shallow sea separating Japan from the mainland. During the Ice Age which ended 12,000 years ago, sea levels were much lower than they are today. It is probable that during the last Ice Age there were land bridges connecting Japan to the mainland at these two points.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-28T13:48:20.867" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17596" PostTypeId="2" ParentId="17541" CreationDate="2019-07-30T05:21:38.490" Score="1" Body="&lt;p&gt;A &lt;a href=&quot;https://phys.org/news/2019-07-global-energy.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;recent study&lt;/a&gt; says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;in temperate zones, a warming climate will increase the energy used for cooling during summer but reduce the energy used for heating during winter.&lt;br&gt;&#xA;  &quot;In the tropics, we see a positive effect—energy increase—but as you move away from the tropics, we see a positive and a negative effect,&quot; he says. &quot;When you add up the two positives and the negative, you could in principle get a negative.. .but what we actually see is a substantial positive&quot;—a significant net increase in energy usage.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-07-30T05:21:38.490" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17599" PostTypeId="2" ParentId="17557" CreationDate="2019-07-30T10:11:33.327" Score="1" Body="&lt;p&gt;As @gansub implicitly suggested, you may have a better outcome by defining the output grid as well. &#xA;Check this very similar question: &#xA;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/12057/how-to-interpolate-scattered-data-to-a-regular-grid-in-python&quot;&gt;How to interpolate scattered data to a regular grid in Python?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;After comments, I realize I missed the irregular target grid. Maybe this answer helps:&#xA;&lt;a href=&quot;https://stackoverflow.com/questions/3242382/interpolation-over-an-irregular-grid&quot;&gt;https://stackoverflow.com/questions/3242382/interpolation-over-an-irregular-grid&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5887" LastEditorUserId="5887" LastEditDate="2019-07-31T08:58:30.927" LastActivityDate="2019-07-31T08:58:30.927" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17601" PostTypeId="1" CreationDate="2019-07-30T15:51:09.110" Score="3" ViewCount="55" Body="&lt;p&gt;I am trying to utilize a function that uses calibrated &lt;span class=&quot;math-container&quot;&gt;$^{14}C$&lt;/span&gt; dates. However, my data consists of OSL dates, not &lt;span class=&quot;math-container&quot;&gt;$^{14}C$&lt;/span&gt;. Searching google scholars did not provide any useful results. Since OSL dates are based on radiation, I presume these do not directly translate to calendar years. Is it possible to calibrate OSL dates into calendar year dates?&lt;/p&gt;&#xA;" OwnerUserId="17511" LastEditorUserId="2470" LastEditDate="2019-07-30T17:45:10.047" LastActivityDate="2019-07-30T17:45:10.047" Title="Calibration of OSL dates to calender year dates" Tags="|dating|archaeology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17602" PostTypeId="1" CreationDate="2019-07-29T19:37:40.907" Score="4" ViewCount="237" Body="&lt;p&gt;I am not sure if I am asking it on a correct platform or not.&#xA;A rainy river passes through my village. We suffer both in summer and in rainy seasons due to this. Could anyone explain how to recharge the ground water with river water. What would be the cost?&lt;/p&gt;&#xA;" OwnerDisplayName="The PowerHouse" LastEditorUserId="39" LastEditDate="2019-07-30T19:40:48.900" LastActivityDate="2022-05-21T22:39:29.217" Title="How to recharge ground water directly from river water" Tags="|hydrology|groundwater|rainfall|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17603" PostTypeId="1" CreationDate="2019-07-30T20:31:46.220" Score="4" ViewCount="48" Body="&lt;p&gt;I attended at talk recently at the &lt;a href=&quot;https://www.tgs.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;TGS&lt;/a&gt; office in Houston, TX, by &lt;a href=&quot;http://www.gstulsa.org/Pages/Bios/Marianne%20Rauch%20bio.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Marianna Raunch&lt;/a&gt;. During this talk, a statement was made that for &quot;very large&quot; velocity inversions, &lt;a href=&quot;https://wiki.seg.org/wiki/Dictionary:Semblance&quot; rel=&quot;nofollow noreferrer&quot;&gt;semblance&lt;/a&gt; (or other similar statistical methods) &quot;break&quot; (or do not work) for accurately determining V&lt;sub&gt;RMS&lt;/sub&gt;. Why is this? &lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2019-07-30T20:31:46.220" Title="Seismic velocity inversion &amp; analysis" Tags="|seismic|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17604" PostTypeId="1" CreationDate="2019-07-30T22:10:04.583" Score="4" ViewCount="115" Body="&lt;p&gt;This &lt;a href=&quot;https://twitter.com/celestelabedz/status/1151343172796108800&quot; rel=&quot;nofollow noreferrer&quot;&gt;tweet&lt;/a&gt; shows &quot;Glaciologist Princess Elsa&quot; is actually Caltech geophysics PhD student and cryoseismologist Celeste Labedz.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The BBC News article &lt;a href=&quot;https://www.bbc.com/news/blogs-trending-49149441&quot; rel=&quot;nofollow noreferrer&quot;&gt;What's a 'Science Princess' doing in an ice field in Alaska?&lt;/a&gt; says in a figure caption:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Celeste Labedz had to cut her research trip short as the glacier was too warm.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What risks or problems would a &quot;too warm&quot; glacier pose to a geophysics and cryoseismology based expedition? Might the problem have been more related to safety or to the quality of the data?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2019-08-31T03:39:59.120" Title="Why did &quot;Glaciologist Princess Elsa&quot; have to leave the glacier because it was too warm?" Tags="|climate-change|glaciology|field-measurements|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17605" PostTypeId="2" ParentId="17602" CreationDate="2019-07-30T22:31:48.277" Score="4" Body="&lt;p&gt;What you are asking about is called &quot;Managed Aquifer Recharge&quot; It has been successfully employed in some situations but depends greatly on the geology of the area. The aquifer needs to be relatively shallow with permeable sediments between it and the surface. If the sediments are not permeable (e.g. clay rich or solid rock) The water won't flow down to the aquifer in a reasonable time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As one comment pointed out the water can be diverted into an artificial lake to drain slowly into the sediments. It also may be possible to form a lake by placing a dam on the river.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2019-07-30T22:31:48.277" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17606" PostTypeId="1" CreationDate="2019-07-31T01:37:47.323" Score="2" ViewCount="106" Body="&lt;p&gt;I've read that peak lateral ground acceleration for magnitude 7 - 8 earthquakes is ~1 g at the epicenter (is that correct?), but I'm wondering if it might be significantly higher right at the rupturing fault itself. This paper compares theoretical models of this motion but, in scanning through it, I didn't find any empirical measurements:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011JB009097?fbclid=IwAR0yy3vmLouk8jNz8FlIqPddj-HA4Npyh6rHQSS_qZ12aR29aM2jkkqK1EU&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2011JB009097?fbclid=IwAR0yy3vmLouk8jNz8FlIqPddj-HA4Npyh6rHQSS_qZ12aR29aM2jkkqK1EU&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the approximate range of lateral ground acceleration (and peak velocity), as a function of earthquake magnitude, right at the fault, for strike-slip earthquakes?&lt;/p&gt;&#xA;" OwnerUserId="17513" LastEditorUserId="17513" LastEditDate="2019-07-31T02:18:06.720" LastActivityDate="2019-10-12T21:01:10.240" Title="What is the lateral ground acceleration, at the fault line, during a strike-slip earthquake?" Tags="|earthquakes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17608" PostTypeId="1" CreationDate="2019-07-31T13:13:30.533" Score="5" ViewCount="77" Body="&lt;p&gt;Organic manure is used in agriculture around the globe.&#xA;I am interested in how does organic matter affect the salinity of soil? Does it increases, increases or remains unaffected? and is there a study to support the argument?&lt;/p&gt;&#xA;" OwnerUserId="17519" LastActivityDate="2019-08-01T07:20:17.893" Title="Effect of organic matter on salinity" Tags="|agriculture|salinity|soil-science|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17609" PostTypeId="2" ParentId="17608" CreationDate="2019-07-31T14:37:07.027" Score="1" Body="&lt;p&gt;Organic matter affects the pH and makes the soil more acidic. The best example of this is in peat bogs, where only acid tolerant plants can live and the peat is so acidic that micro-organisms don't flourish, thus preventing decay. There is the famous Tollund Man, found in a peat bog in Denmark if I remember rightly. The body is in an almost perfect state of preservation, yet is about 3,000 years old! Tollund Man was apparently executed by hanging in ancient times and his body thrown into the bog. The principle is the same as the jars of eggs, onions, gherkins and so on which are pickled in vinegar.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="2470" LastEditDate="2019-08-01T02:44:15.637" LastActivityDate="2019-08-01T02:44:15.637" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17611" PostTypeId="1" AcceptedAnswerId="17621" CreationDate="2019-07-31T15:48:37.780" Score="10" ViewCount="4907" Body="&lt;p&gt;Can living in a region that is rich in (rare) earth metal that has an inherently strong magnetic field provide any protection from cosmic radiation? Where are the strongest magnetic field other than the north or south pole and is there a map of these areas?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Related: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/17561/how-would-our-weather-change-in-the-event-of-a-magnetic-pole-shift?noredirect=1#comment37812_17561&quot;&gt;How would our weather change in the event of a magnetic pole shift?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorUserId="5052" LastEditDate="2019-08-05T12:00:20.920" LastActivityDate="2019-08-05T15:59:32.063" Title="Can living where (rare) earth magnetic ore is abundant provide any protection from cosmic radiation?" Tags="|mapping|moon|magmatism|ore|" AnswerCount="6" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17612" PostTypeId="1" CreationDate="2019-07-31T16:35:18.907" Score="2" ViewCount="122" Body="&lt;p&gt;In his &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/3030168794&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;recent book&lt;/a&gt;, Rex J. Fleming asserts that &quot;CO&lt;sub&gt;2&lt;/sub&gt; has no impact on climate change&quot;, or, as he summarizes on &lt;a href=&quot;http://rexfleming.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;his website&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;There are now over a dozen books available on Amazon.com that point out the various fallacies of the CO2 climate theory – but none of these have zeroed in on the heart of the issue – the failure of the Schwarzschild radiation integrations to maintain the CO2 longwave radiation intensity achieved in the surface warming by H2O and CO2. The resultant Planck radiation intensity is severely depleted in the upper atmosphere. The result is the CO2 molecules merely pass their remaining small residual heat to space un-impeded. CO2 has no impact on climate change.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This claim seems to contradict some &lt;a href=&quot;https://skepticalscience.com/empirical-evidence-for-co2-enhanced-greenhouse-effect-advanced.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;basic physics&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is Fleming correct that the &quot;failure of the Schwarzschild radiation integrations to maintain the CO2 longwave radiation intensity&quot; means that &quot;CO2 has no impact on climate change&quot;?&lt;/p&gt;&#xA;" OwnerUserId="4823" LastActivityDate="2019-07-31T20:39:24.240" Title="Does depletion of Planck radiation intensity in the upper atmosphere mean that &quot;CO2 has no impact on climate change&quot;?" Tags="|climate-change|atmospheric-radiation|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17614" PostTypeId="2" ParentId="17612" CreationDate="2019-07-31T20:39:24.240" Score="-2" Body="&lt;p&gt;Talk of Schwarzschild radiation integrations negating the effect of CO2 in atmospheric warming is just mumbo jumbo on a par with creationism, but there is a danger of going too far in the other direction. Carbon dioxide forms 0.0325 percent of the atmosphere, and although a slight increase has been recorded in the past 100 years and attributed to human activity, this increase is infinitesimally small. Whenever I say that climate warming began 12,000 years ago it is always very unpopular, but it nevertheless happens to be a fact. There is unanimous agreement among scientists that the small amount of CO2 in the atmosphere helps to warm the Earth, but where there is less agreement is on the question of whether the minute increase since the industrial revolution has measurably accelerated the climate warming which had already been underway for 12,000 years. Another unpopular idea which also happens to be a fact is that increased atmospheric CO2 causes plants to grow more vigorously, so to some extent increased CO2 content is self-correcting, but only up to a point. It could easily be overwhelmed if the CO2 increase is too rapid. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-31T20:39:24.240" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17615" PostTypeId="2" ParentId="17611" CreationDate="2019-07-31T20:41:19.643" Score="11" Body="&lt;p&gt;&lt;strong&gt;No.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cosmic radiation are high-energy particles that create particle showers high up in the terrestrial atmosphere. Those particle shower are heavily beamed downwards, and although in principle some secondary shower products feel the local magnetic fields, effectively are not affected by the natural terrestrial field, let alone weaker local fields.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Those showers also create hard photon radiation (X-rays) which contribute to the local background radiation and those wouldn't react to any magnetic field.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2019-07-31T20:41:19.643" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17616" PostTypeId="2" ParentId="17611" CreationDate="2019-07-31T20:58:46.493" Score="8" Body="&lt;p&gt;Yes, there are maps that map out variations in the earth's magnetic field, example here &lt;a href=&quot;http://science.gc.ca/eic/site/063.nsf/eng/97358.html&quot; rel=&quot;noreferrer&quot;&gt;http://science.gc.ca/eic/site/063.nsf/eng/97358.html&lt;/a&gt;. The large variations are primarily due to the presence of ferric materials, ie large deposits of material like magnetite.  There are no areas of rare earth magnets as far as I know, given that rare earth magnets are made from rare earth minerals artificially sintered in a very strong magnetic field suggests you will not find them naturally.  Even if you did find an area the effect on cosmic radiation would be very small.  The magnetic field earth is weak but very large and extends far outside our atmosphere allowing the energetic cosmic and solar particles to be trapped and or slowed.  Local magnetic anomalies wouldn't have the time to influence the particles much.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the poles shift we will have to ride out the transition as best we can.  I am not aware of any major extinction event being associated with prior pole shifts, but I could be wrong.  You also have to consider when the poles shift the magnetic fields that induce the current magnetic anomolies will be different or missing so you wouldn't be able to depend your chosen location being safe.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So unless you want to live underground I don't believe there are areas where the local magnetic fields will protect you from cosmic radiation.  &lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2019-07-31T20:58:46.493" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17617" PostTypeId="2" ParentId="17611" CreationDate="2019-07-31T21:33:57.480" Score="2" Body="&lt;p&gt;Magnetite is a type of iron ore and does not significantly affect the Earth's magnetic field. It would not protect you from cosmic radiation. However, cosmic radiation is more intense high in the atmosphere, so airline cabin crew and people living on high mountains are slightly more at risk. If you are worried about how to avoid radiation damage, the thing to watch out for is radon gas. Radon gas is released by the decay of uranium in granite rocks, and varies in different parts of Britain. In some places it can reach dangerous levels which would not be tolerated in a nuclear power station or research establishment. There are indeed maps available on the internet which show levels of radon gas throughout Britain. Cornwall is one of the high radon areas, whereas Herefordshire is a low to moderate area. Radon is invisible, tasteless and odourless, and emits high energy alpha particles (helium nuclei) to become a radioactive isotope of lead. Alpha particles are not very penetrating and can be stopped by a thin sheet of paper, but when inhaled or otherwise ingested can be very dangerous because of their ionising effect. If you live in a high radon area, it is best to keep your house well ventilated.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-07-31T21:33:57.480" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17620" PostTypeId="2" ParentId="5255" CreationDate="2019-08-01T01:44:31.200" Score="1" Body="&lt;p&gt;Same experience two weeks ago north of Charleston, SC: could very clearly see abundant lightning in the top of a distant bank of clouds east over the ocean at nighttime with no moon. It was spectacular. But the radar showed that storm to be a little over 150 miles out to sea...&lt;/p&gt;&#xA;" OwnerUserId="17526" LastActivityDate="2019-08-01T01:44:31.200" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17621" PostTypeId="2" ParentId="17611" CreationDate="2019-08-01T03:43:29.323" Score="22" Body="&lt;h1&gt;Absolutely not.&lt;/h1&gt;&#xA;&lt;p&gt;First of all, &amp;quot;rare earth magnet ore&amp;quot;, meaning the ores of metals like neodymium (Nd) and samarium (Sm), is not magnetic at all. It only becomes a magnet once you make a magnet out of it. For example, one such magnet is Nd&lt;sub&gt;2&lt;/sub&gt;Fe&lt;sub&gt;14&lt;/sub&gt;B  and it only becomes a magnet after neodymium is combined with iron and boron.&lt;/p&gt;&#xA;&lt;p&gt;Naturally occuring neodymium ore is usually in the form of minerals such as bastnäsite (a rare earth carbonate) or monazite (rare earth phosphate) that are &lt;em&gt;not&lt;/em&gt; magnetic.&lt;/p&gt;&#xA;&lt;h1&gt;It gets even worse!&lt;/h1&gt;&#xA;&lt;p&gt;Even if by some force of magic the rare earth ore would protect you from cosmic radiation, you now have two problems:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Most rare earth ore also has significant amounts of the radioactive thorium and uranium. You do not want to live in these areas, as any &amp;quot;protection&amp;quot; from cosmic radiation will be more than compensated for by the background radiation of the place you are now living in.&lt;/li&gt;&#xA;&lt;li&gt;These are not nice places to live in. The three operating or recently operating rare earth extraction operations (aka mines) are in the desert. Bayan Obo in China, Mount Weld in Australia, and Mountain Pass in the United States.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-08-01T03:43:29.323" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="17622" PostTypeId="2" ParentId="17608" CreationDate="2019-08-01T07:14:20.040" Score="0" Body="&lt;p&gt;First of all the whole idea by using fertilizer is to add different types of salts to the soil,Fertilizers from animals or plants will contain most of the types of salts the animals or plants have absorbed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I guess you are asking about NaCl and yes manure will over time acumulate this type of salt in the soil,But we are talking many years or decades before this is a problem and other types of salts will build up too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main way the animals get rid of exsess salt is in the urine and if one use this for fertilizer the build up of NaCl will be greater in the soil.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Fertilizer&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Fertilizer&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A lot of the salts will be removed by rain and irrigation so the build up of salts is mostly a problem in dry areas of the world,And crop rotation might help keeping the salt level down(if it is done right).&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6258" LastEditDate="2019-08-01T07:20:17.893" LastActivityDate="2019-08-01T07:20:17.893" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17623" PostTypeId="1" CreationDate="2019-08-01T08:03:54.003" Score="2" ViewCount="144" Body="&lt;p&gt;The current and future amount of carbon (in the form of carbon dioxide) in the atmosphere and the hydrosphere is what currently concerns and occupies many people. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am looking for a big picture of the net fluxes between different carriers of carbon that gives a good idea where the &lt;a href=&quot;https://www.wikiwand.com/en/Carbon_dioxide_in_Earth%27s_atmosphere#/Atmospheric_carbon_dioxide_and_the_carbon_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;anthropogenic CO&lt;sub&gt;2&lt;/sub&gt; emissions&lt;/a&gt; (and other greenhouse gases) actually did come from (compared to e.g. 1500, 1800, 1900, 1950 and 2000).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I am looking for rough (and possibly estimated) numbers like these - optimally in an overview, so the numbers sum up to 100:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;p&lt;sub&gt;1&lt;/sub&gt;% by fossil fuel burning&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;p&lt;sub&gt;2&lt;/sub&gt;% from the natural biosphere (which decreased), esp. deforestation &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;p&lt;sub&gt;3&lt;/sub&gt;% from cultivated biosphere (which increased), incl. methane emissions from cattle &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;p&lt;sub&gt;4&lt;/sub&gt;% from industrial abiotic chemical processes, e.g. cement production&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;p&lt;sub&gt;k&lt;/sub&gt;% other important sources with p&lt;sub&gt;k&lt;/sub&gt; &gt; 1%?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;p&lt;sub&gt;6&lt;/sub&gt;% other?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="17431" LastEditorUserId="489" LastEditDate="2019-08-02T12:20:55.330" LastActivityDate="2019-08-02T12:20:55.330" Title="Net fluxes of carbon caused by humans" Tags="|atmosphere|oceanography|carbon-cycle|biomass|anthropocene|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17625" PostTypeId="1" CreationDate="2019-08-01T11:35:59.723" Score="3" ViewCount="34" Body="&lt;p&gt;I know how to calculate it by remote sensing image, but why do we define this? &#xA;What can we know about a remote sensing scene by this indicator? &#xA;What's the connection between normalized difference Built-up index and Built up area?&lt;/p&gt;&#xA;" OwnerUserId="17528" LastEditorUserId="2470" LastEditDate="2019-08-01T14:15:50.807" LastActivityDate="2019-08-01T14:15:50.807" Title="What is the meaning of nomalized difference Built-up index？" Tags="|geography|remote-sensing|mathematics|urban-climate|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17626" PostTypeId="2" ParentId="17611" CreationDate="2019-08-01T12:36:24.833" Score="2" Body="&lt;p&gt;Although the other answers have correctly pointed out that this isn't a relevant thing on Earth, it should be mentioned that such an effect &lt;em&gt;does&lt;/em&gt; occur on the Moon: it is the likely cause for the &lt;a href=&quot;https://en.wikipedia.org/wiki/Lunar_swirls&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lunar swirls&lt;/a&gt;. These are though to be the result of magnetic anomalies causing local shielding of the surface from solar wind. This effect prevents the regions from proton “sun tan”, i.e. they aren't as dark as the rest of the surface, which is what we can from Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But those particles for which this shielding works on the Moon are already 100% shielded from the Earth surface through Earth's internal dipole field and through its atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="12095" LastActivityDate="2019-08-01T12:36:24.833" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17628" PostTypeId="1" CreationDate="2019-08-01T19:05:38.090" Score="4" ViewCount="354" Body="&lt;p&gt;My simplistic model for the carbon cycle was that plants (or trees in particular) photosynthesise and transpire. The former takes up &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{H_2O}$&lt;/span&gt; and the latter does the reverse but obviously not netting out. The carbon for the cellular material (in particular wood) comes entirely from atmospheric &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; (?).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mass of trees comes mainly from cellulose which is roughly 50% carbon. Therefore the mass of sequestered &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; is simply related to the mass of trees, with the proportion equal to the ratio of the molecular masses of cellulose and &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; with balanced carbon content. Wiki says cellulose is some sort of sugar type thing &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{(C_6H_{10}O_5)n}$&lt;/span&gt; and carbon dioxide is obviously &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; so the ratio is something like: for each kilo of tree/wood grows 1.62 kg of &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; is sequestered?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this completely wide of the mark?&lt;/p&gt;&#xA;" OwnerUserId="17529" LastEditorUserId="6129" LastEditDate="2020-05-08T06:12:26.127" LastActivityDate="2020-05-08T06:12:26.127" Title="Is the net amount of CO2 sequestered by trees from the atmosphere simply related to the mass of new growth?" Tags="|co2|carbon-cycle|carbon|" AnswerCount="2" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17630" PostTypeId="1" CreationDate="2019-08-01T20:07:06.693" Score="1" ViewCount="82" Body="&lt;p&gt;I am only 14 so please don't criticize me too harshly. From what I have understood from my teachers is that our ozone layer helps deflect harmful Ultra Violet Rays and that currently our ozone layer is being destroyed by chlorofluorocarbons(CFC's)were emitted by humans. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the early 60's the effects of them were not known and they were used in many products and it takes approximately 50 years for the CFC's to travel to our ozone layer. When CFC's penetrate through the ozone layer they ley harmful ultra violet rays in which can damage our body's and during prolonged exposure may cause cancer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As I have understood using CFC's that will be emitted is banned everywhere except for in third world country's. If we also halt CFC's from being unleashed into the atmosphere in third world country's then I think that it would decrease the cases of cancer in general drastically. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you for reading this far and if I am misunderstood about any of these statements please correct me in the comments.&lt;/p&gt;&#xA;" OwnerUserId="17531" LastEditorUserId="6467" LastEditDate="2019-08-04T20:13:06.347" LastActivityDate="2019-08-04T20:13:06.347" Title="Ozone Layer Problem" Tags="|ozone|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17631" PostTypeId="2" ParentId="17628" CreationDate="2019-08-01T20:35:58.393" Score="1" Body="&lt;p&gt;Plants and trees both do the same thing: they take CO2 from the atmosphere and water from the soil and using the energy of the sun via photosynthesis they create glucose with it. The glucose is then converted into cellulose. I was puzzled by your remark that one of the two, either trees or plants, does the opposite. It doesn't. Although trees pay a large part in  removing CO2 from the atmosphere, it's easy to overemphasise their role. Other plants also play a large part, especially in peat bogs, but what few people seem to realise is that photosynthetic marine organisms such as cyanobacteria, phytoplankton, blue-green algae, seaweed and and sea grass etc absorb more CO2 than all the worlds rainforests. How much this all adds up to in terms of tons of CO2 per year removed from the atmosphere is impossible to estimate, especially as in some cases (wood burning and food consumption, for example) the CO2 is soon given back to the atmosphere, while in peat bogs it is removed for good.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-01T20:35:58.393" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17632" PostTypeId="2" ParentId="17630" CreationDate="2019-08-01T21:07:18.130" Score="1" Body="&lt;p&gt;The problem of CFCs damaging the ozone layer was recognised many years ago in advanced western countries, and they were soon banned and replaced with other more environment friendly gases. There was an ozone hole over the Antarctic which advanced and receded with the seasons. It is still there, but smaller than it used to be. To some extent it is a natural event caused by bromine compounds arising from the sea, but made worse by the advent of CFCs. It is no longer a major problem and is not expected to get worse, as CFCs are being used less and less.. You are right about too much ultraviolet being bad for our health, but too little can also be bad, because it encourages a bone disorder called rickets. I used to overdo the sunbathing when I was young, but now I keep it to sensible levels. I didn't get skin cancer, but you're right, a lot of people do. However, excessive sunbathing and use of sunbeds is only one cause of cancer. There are many other cancers besides skin cancer, and they are nearly all due to unhealthy lifestyles and therefore nearly all preventable.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-01T21:07:18.130" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17633" PostTypeId="1" CreationDate="2019-08-01T21:27:46.810" Score="3" ViewCount="144" Body="&lt;p&gt;I found spherical or globular structures, structures in basalts of a greenstone belt which underwent alteration and deformation. However, in thin section, these structures have undeformed pyroxene and olivine. Below is a field picture of the structure. Would anyone know what these structures are called and how they form?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mvduq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mvduq.png&quot; alt=&quot;Globular Structure in Basalt&quot;&gt;&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="17533" LastEditorUserId="6467" LastEditDate="2019-09-01T18:52:51.357" LastActivityDate="2021-05-23T22:01:50.187" Title="&quot;Obicular&quot; structures in basalts" Tags="|geology|mineralogy|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17634" PostTypeId="2" ParentId="17623" CreationDate="2019-08-01T23:56:13.373" Score="3" Body="&lt;p&gt;There are various &lt;a href=&quot;https://www.google.ca/search?client=ubuntu&amp;amp;hs=yEi&amp;amp;biw=1203&amp;amp;bih=643&amp;amp;tbm=isch&amp;amp;sa=1&amp;amp;ei=YHRDXaWOEKvH0PEPi6Wt2Ao&amp;amp;q=fossil+cement+%22land+use%22+CO2+emissions&amp;amp;oq=fossil+cement+%22land+use%22+CO2+emissions&quot; rel=&quot;nofollow noreferrer&quot;&gt;charts&lt;/a&gt; but not exactly what you want. This one combines burning, industry and cement but shows land sources and sinks separately:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/BF7m6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BF7m6.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.carbonbrief.org/what-global-co2-emissions-2016-mean-climate-change&quot; rel=&quot;nofollow noreferrer&quot;&gt;CarbonBrief&lt;/a&gt;,  Le Quéré, C. et al. (&lt;a href=&quot;https://doi.org/10.5194/essd-8-605-2016&quot; rel=&quot;nofollow noreferrer&quot;&gt;2016&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="106" LastEditDate="2019-08-02T10:54:57.197" LastActivityDate="2019-08-02T10:54:57.197" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17638" PostTypeId="2" ParentId="17633" CreationDate="2019-08-02T09:44:01.950" Score="1" Body="&lt;p&gt;These globular structures are called varioles, and there is not complete agreement as to how they are formed. The most likely theory is that the basalt has been hydrothermically altered by millions of years of water infiltration bringing in tiny amounts of other minerals, but the jury is still out.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-02T09:44:01.950" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17639" PostTypeId="2" ParentId="17611" CreationDate="2019-08-02T11:35:01.003" Score="2" Body="&lt;p&gt;The magnetic field stops the charged particles mostly by trapping them along their fields lines (globally parallel to the ground at most latitudes, plunging to the ground near the poles (therefore allowing northern lights).&#xA;If you 1up nature and build a massive electromagnet, you could at most create a secondary pole, which would act as particle channel to you, increasing the cosmic radiation you would suffer.&lt;/p&gt;&#xA;" OwnerUserId="17538" LastEditorUserId="5052" LastEditDate="2019-08-02T11:36:02.673" LastActivityDate="2019-08-02T11:36:02.673" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17641" PostTypeId="1" CreationDate="2019-08-02T15:05:21.713" Score="3" ViewCount="156" Body="&lt;p&gt;I have come across two (apparently) different equations for this purpose. One is mentioned in BASINS software code &lt;a href=&quot;https://github.com/respec/BASINS/blob/4356aa9481eb7217cb2cbc5131a0b80a932907bf/atcMetCmp/modMetCompute.vb#L1251&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$Rad\_len [inday^{-1}] = \frac{SolRad[langleysday^{-1}]}{((597.3 - 0.57 * temp[centigrade])*2.54)}  $$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;while the equation mentioned in &lt;a href=&quot;http://www.fao.org/3/X0490E/x0490e07.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;FAO-56 Allen et al 1998&lt;/a&gt; (2) in chapter 3 is &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$Rad\_len[mmday^{-1}] = \frac{SolRad[MJm^{-2}day{-1}]}{2.45}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't see any resemblence between these two equations even after converting &lt;span class=&quot;math-container&quot;&gt;$langleysday^{-1}$&lt;/span&gt; to &lt;span class=&quot;math-container&quot;&gt;$MJm^{-2}day{-1}$&lt;/span&gt; (which can be done by using a factor of 0.041868). The first equation is used in the evapotranspiration estimation method from radiation using given by in Jensen and Haise, 1963 (2).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1) Allen, R. G., Pereira, L. S., Raes, D., &amp;amp; Smith, M. (1998). Crop evapotranspiration-Guidelines for computing crop water requirements-FAO Irrigation and drainage paper 56. Fao, Rome, 300(9), D05109.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) Jensen, M. E., &amp;amp; Haise, H. R. (1963). Estimating evapotranspiration from solar radiation. Proceedings of the American Society of Civil Engineers, Journal of the Irrigation and Drainage Division, 89, 15-41&lt;/p&gt;&#xA;" OwnerUserId="5557" LastActivityDate="2019-08-02T15:05:21.713" Title="How to convert solar radiation into equivalent evaporation" Tags="|atmospheric-radiation|evaporation|radiation-balance|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17644" PostTypeId="1" CreationDate="2019-08-03T03:30:02.027" Score="1" ViewCount="1960" Body="&lt;p&gt;This here is a map of the Brooks Range in northern Alaska:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mWa6M.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mWa6M.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see, it is an inland range shaped in a downward curve.  Why is that?  What is the history of the uplift of the Brooks Range?  How and when did a piece of sea or lowland rise up into a downward-curving mountain range far from the coast?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastActivityDate="2019-08-03T06:16:43.243" Title="What is the History of the Brooks Range?" Tags="|geology|mountains|mountain-building|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17645" PostTypeId="2" ParentId="17644" CreationDate="2019-08-03T05:17:12.193" Score="3" Body="&lt;p&gt;If you extend your map out a little bit further, you will see that the Brooks Range is just a continuation of the Rocky Mountains into Alaska.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://www.freeworldmaps.net/northamerica/northamerica-physical-map-highres.jpg&quot; alt=&quot;North America mountains&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Source: &lt;a href=&quot;https://www.freeworldmaps.net/northamerica/&quot; rel=&quot;nofollow noreferrer&quot;&gt;freeworldmaps.net&lt;/a&gt;, ©Daniel Feher (explicitly permitted use &lt;a href=&quot;https://www.freeworldmaps.net/about.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Brooks Range was formed at the same time as the front ranges of the Rockies in Canada and the Lower 48, during the &lt;a href=&quot;https://en.wikipedia.org/wiki/Laramide_orogeny&quot; rel=&quot;nofollow noreferrer&quot;&gt;Laramide Orogeny&lt;/a&gt; which lasted from abut 80 million years ago to about 35 million years ago.  This was caused by the subduction of oceanic plates (mainly the &lt;a href=&quot;https://en.wikipedia.org/wiki/Farallon_Plate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Farallon Plate&lt;/a&gt; but also the &lt;a href=&quot;https://en.wikipedia.org/wiki/Kula_Plate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kula Plate&lt;/a&gt;, and to a lesser extent, the Pacific Plate) beneath the west coast of North America.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Farallon plate went &lt;a href=&quot;https://en.wikipedia.org/wiki/Flat_slab_subduction&quot; rel=&quot;nofollow noreferrer&quot;&gt;under North America at a shallow angle&lt;/a&gt;; because of this, a large part of Western North America was uplifted, deep into the continent, with faults pushing ancient basement rocks up where the Front Ranges and the Brooks Range are today. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/4/48/North_America_subduction1.jpg&quot; alt=&quot;Plates 55 Ma&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pacific Ocean plates, 55 Ma. &lt;em&gt;Source: Wikimedia Commons&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Kula plate is &quot;all gone&quot;, and the Farallon Plate is mostly gone, except for a few remnants like the Juan de Fuca Plate. Because of the different direction that the Pacific Plate moves, subduction ialong the West Coast is mostly gone as the Pacific Plate slides past North America. The shallow subduction that created mountains deep in the interior is done.  A subduction zone further west has created the Aleutian volcanic arc, but this is a much steeper subduction.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2019-08-03T06:16:43.243" LastActivityDate="2019-08-03T06:16:43.243" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17651" PostTypeId="1" AcceptedAnswerId="17656" CreationDate="2019-08-03T22:15:24.783" Score="1" ViewCount="80" Body="&lt;p&gt;Are there a mini-magnetosphere within the magnetosphere similar to mini-magnetosphere found on the Moon? Is there a map of these areas that would resemble the white swirls in the picture below? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The white areas extending up to 360 km and are the safer areas where one could be protected to a degree. &#xA;&lt;a href=&quot;https://i.stack.imgur.com/EQpsh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EQpsh.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there areas on Earth that could have this magnetic crustal properties as the moon has and would it add or supplement the protection of Earth's magnetosphere? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jUF5K.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jUF5K.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;Source: &lt;a href=&quot;http://lunarnetworks.blogspot.com/2010/10/grand-lunar-swirls-yielding-to-lro-mini.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://lunarnetworks.blogspot.com/2010/10/grand-lunar-swirls-yielding-to-lro-mini.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T11:55:08.653" LastActivityDate="2019-08-29T11:55:08.653" Title="Can living where magnets are abundant provide a mini-magnetoshere?" Tags="|geology|models|magnetosphere|rock-magnetism|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17652" PostTypeId="1" CreationDate="2019-08-04T00:25:10.037" Score="5" ViewCount="3573" Body="&lt;p&gt;I've read about how ionospheric discharges like jets can be initiated/triggered by lightning, and how lightning can propagate upwards from clouds.  What I was wondering is if this can happen in reverse.  In other words, can ionospheric plasma disturbances/discharges affect/trigger troposphere to ground lightning?&lt;/p&gt;&#xA;" OwnerUserId="7227" LastEditorUserId="543" LastEditDate="2023-08-04T19:53:56.830" LastActivityDate="2023-08-04T19:53:56.830" Title="Can ionospheric plasma disturbances affect the weather?" Tags="|lightning|upper-atmosphere|ionosphere|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17655" PostTypeId="2" ParentId="17652" CreationDate="2019-08-04T09:35:59.750" Score="2" Body="&lt;p&gt;The ionosphere is too high up to affect the weather far below in the troposphere. It's more the other way around. Lightning discharges in the troposphere sometimes send vertical columns called sprites and jets up into the ionosphere. The sprites are coloured orangey red or sometimes greenish blue, the same colours as aurorae, and for the same reason. One colour is from the excitation of oxygen ions, and the other comes from nitrogen ions, but I forget which colour comes from which gas. I think red comes from nitrogen. Jets are more white in colour, longer, straighter and less variable in shape than sprites. Both phenomena are comparatively new discoveries, being first photographed in 1989.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ionosphere begins about 35 miles up, some 18 miles above where the ozone layer leaves off. It is chiefly notable for its ability to reflect radio transmissions, enabling them to follow the curvature of the Earth though in other circumstances they would travel in a straight line. The layer which does this is called the Heaviside layer. Meteors begin to burn up in the upper ionosphere.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-08-04T09:50:47.353" LastActivityDate="2019-08-04T09:50:47.353" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17656" PostTypeId="2" ParentId="17651" CreationDate="2019-08-04T10:02:23.307" Score="1" Body="&lt;p&gt;Near to the Earth's surface there are small variations in the Earth's magnetic field, but these don't play a role in providing the magnetosphere which protects the Earth from charged particles emanating chiefly from the solar wind.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-04T10:02:23.307" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17657" PostTypeId="1" CreationDate="2019-08-04T21:12:13.080" Score="2" ViewCount="258" Body="&lt;p&gt;I often see claims that volcanic emissions of sulphur dioxide, on Earth and on the planet Venus, creates sulphuric acid when it combines with water vapour. It doesn't. Sulphur dioxide creates sulphurous acid, which is less corrosive than sulphuric acid. To make sulphuric acid you need sulphur trioxide. Is there a natural process which converts sulphurous acid into sulphuric acid, or has one  acid been confused with the other? &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-05T03:23:32.240" Title="Origin of Sulphuric Acid in the Atmosphere" Tags="|atmospheric-chemistry|air-pollution|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17659" PostTypeId="2" ParentId="17657" CreationDate="2019-08-05T03:23:32.240" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Oxidation states of sulphur vary between -2 and +6. Sulphur compounds are generally&#xA;  emitted in reduced form. They are then oxidised in the Earth’s atmosphere, generally to&#xA;  SO2&#xA;  , a +4 oxidation state. Around 65% (the remainder is removed by dry deposition) of this&#xA;  sulphur dioxide is eventually oxidised to the +6 state of H2SO4&#xA;  , where SO2 –&#xA;  4&#xA;  is the sulphate&#xA;  ion. Sulphur is stable in the presence of oxygen in this state. The higher-state compounds&#xA;  also generally have a greater affinity to water, meaning they are more readily removed from&#xA;  the atmosphere by wet deposition. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.met.reading.ac.uk/~qq002439/aferraro_sulphcycle.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;The natural atmospheric sulphur cycle and its response to anthropogenic perturbations, Angus J. Ferraro&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-08-05T03:23:32.240" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17660" PostTypeId="1" CreationDate="2019-08-05T04:39:47.197" Score="12" ViewCount="3893" Body="&lt;p&gt;If you are in an airplane well above ground level, but low enough to see the faces of people relatively easily, and an earthquake happens, will you see the ground shake?&lt;/p&gt;&#xA;" OwnerUserId="17558" LastEditorUserId="39" LastEditDate="2019-08-05T05:36:44.833" LastActivityDate="2019-08-05T20:02:22.867" Title="Would the shaking of an earthquake be visible to somebody in a low-flying aircraft?" Tags="|earthquakes|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="17661" PostTypeId="2" ParentId="17660" CreationDate="2019-08-05T08:27:45.407" Score="1" Body="&lt;p&gt;Whether you would see the ground shake or not depends on the magnitude of the earthquake. If you are talking about the kind of quakes we have in Britain, then no, you wouldn't see anything. Even on the ground you wouldn't see anything, though you might feel the vibrations (I have felt them myself). On the other hand, if you mean the sort of magnitude 7 or  8 earthquakes sometimes experienced in places along the San Andreas fault in California, in Iran, Japan, Indonesia and other parts of the world, you most certainly would see the quake happening from a low flying plane. Sometimes these huge quakes open up great cracks in the earth, stretching for hundreds of metres, roads are severed in a fraction of a second, with the two ends severely misaligned, bridges collapse, the tops of tall buildings sway, and so on. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-05T08:27:45.407" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17662" PostTypeId="1" CreationDate="2019-08-05T09:02:56.520" Score="1" ViewCount="168" Body="&lt;p&gt;Does anyone know an online source to illustrate glacial extent variability during last ice age, ca 120 ka BP to 10 ka BP? Most sources seem to concentrate only on the maximum, but apparently, there was quite a lot of variability. I'm mostly interested in Europe.&lt;/p&gt;&#xA;&lt;p&gt;Thanks for any hints.&lt;/p&gt;&#xA;" OwnerUserId="3385" LastEditorUserId="18081" LastEditDate="2020-08-31T08:40:33.957" LastActivityDate="2020-09-30T17:19:20.560" Title="Glacial extent variability during last glacial period?" Tags="|ice-age|glaciation|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17663" PostTypeId="2" ParentId="2964" CreationDate="2019-08-05T10:23:36.787" Score="1" Body="&lt;p&gt;The earliest photosynthetic marine organisms (cyanobacteria) are known to have been established by 3.8 billion years ago from the isotopic composition of sedimentary rocks. The earliest microfossils of such organisms are dated at 3.5 billion years. Therefore these photosynthetic micro-organisms were pumping oxygen into the ocean and into the atmosphere at least 1.1 billion years before the Great Oxygenation Event and more likely 1.6 billion. In that almost unimaginably long span of time, these organisms must have created staggering amounts of oxygen. Much of it was soon dissolved and dispersed in the surrounding ocean, but some must have leaked into the CO2 and N2 atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is impossible to believe that after a thousand million years of oxygen production, not enough had leaked into the atmosphere to give it a measurable amount, notwithstanding the fact that there was no one around at the time to measure it. Some oxygen had been mopped up by iron and other elements from the earliest days, but not enough to show up clearly in the stratigraphic record until the so-called Great Oxygenation Event. It defies common sense to say that there was a sudden explosion of oxygen production 2.4 billion years ago and no significant amount had leaked into the atmosphere well before then. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the answer to your question is no, there is not conclusive evidence to refute an earlier oxygenation of Earth's atmosphere. The question is, to what extent did it happen, rather than whether it happened. In other words, what was the percentage of O2 in the earth's atmosphere at, say, 250 million years before the GOE? We may be sure it was far less than in today's atmosphere, but nevertheless a significant amount and (at the time) an easily measurable amount.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-05T10:23:36.787" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17664" PostTypeId="2" ParentId="17660" CreationDate="2019-08-05T12:20:42.963" Score="11" Body="&lt;p&gt;It depends largely on how deep, or shallow, the earthquake is, how large, and what kind of terrain you're looking down on. Some fairly large earthquakes, magnitude 6-7, can have very little surface effect, when they are centred 5+km down as many earthquakes in New Zealand often are. The finer the sediment on the surface, and the thicker the sediment cover, the greater the ground shaking is at the surface and the more motion is usually visible. Different ground covers will also make shaking more or less visible, long grass, or cereal crops, on a windy day will look like they're in motion even without a 'quake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shallow earthquakes often result in apparent &lt;a href=&quot;https://en.wikipedia.org/wiki/Love_wave&quot; rel=&quot;noreferrer&quot;&gt;L-wave&lt;/a&gt; activity, by which I mean that you can actually watch the ground wave coming towards you if you're outside on relatively flat ground, even during relatively small 3-4 pointer 'quakes. These waves also make parked vehicles rock from side to side, I would expect these effects to be the most visible from the air in the case of small to moderate earthquakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Larger 'quakes will cause noticeable shaking of buildings, power poles, aerials etc... even when quite deep and possibly distortion to large linear features such as roads, railways, waterways, and crop and orchard rows. These distortions would be visible as they form, and, when large enough, from very high in the air. &lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2019-08-05T12:20:42.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17665" PostTypeId="1" CreationDate="2019-08-05T12:31:16.657" Score="1" ViewCount="127" Body="&lt;p&gt;At a very rough estimate, what proportion of wildfires are caused by natural events like lightning? I am absolutely sure that in Europe, where there are often wildfires, the sun is never hot enough to set fire to vegetation directly, though it obviously makes things tinder dry and easily combustible. The broken bottle theory has been disproved. Experiments involving broken glass among highly combustible straw or hay were unsuccessful in causing combustion, though manual focussing of the suns rays with the lens-shaped bottom of a bottle were on rare occasions and with much difficulty successful. Although lightning undoubtedly causes the occasional wildfire, the majority have no connection with lightning. It should also be remembered that lightning is usually accompanied by torrential rain. These fires often start in several places at once, which is stretching the long arm of coincidence a bit too far. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apart from the very rare instances of volcanos causing wildfires, what other natural causes could there be?&#xA;Comparison of wildfire frequency in tinder-dry uninhabited areas, well away from civilisation, versus frequency in or near similar but populated areas should give a good idea of the scale of the problem.  &lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-08-06T07:00:49.790" LastActivityDate="2019-08-07T13:31:08.200" Title="Origin of Serious Wildfires" Tags="|climate-change|climate|air-pollution|forest|wildfire|" AnswerCount="1" CommentCount="8" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17666" PostTypeId="2" ParentId="17662" CreationDate="2019-08-05T12:56:58.280" Score="0" Body="&lt;p&gt;There's nothing I can find that gives figures. If you're interested in the extent of ice cover in particular areas it should be possible to create estimates based on temperature proxy data. The extent of ice cover is estimated using the equilibrium line altitude, altered for lower temperatures per the proxy estimates for the area. In this way it can also be possible to identify glacial morphology in now ice-free environments. This is the use of the technique I'm most familiar with, estimating the extent of historic glaciation in mountain ranges so that morphological features can be placed/studied in context.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2019-08-05T12:56:58.280" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17667" PostTypeId="1" AcceptedAnswerId="19355" CreationDate="2019-08-05T13:27:47.627" Score="4" ViewCount="474" Body="&lt;p&gt;The picture below shows how a magnetosphere has defined points on the solid magnet and on the moon where cosmic radiation has a window, gap, or focal point. I'm not sure what to call these areas? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where on Earth are these areas? Is there a map where the magnetosphere or local natural magnetic fields has this same effect?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/67lZM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/67lZM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5052" LastActivityDate="2020-03-03T17:02:54.763" Title="Where are the magnetopheres weak points on Earth?" Tags="|mapping|magnetosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17668" PostTypeId="2" ParentId="17660" CreationDate="2019-08-05T20:02:22.867" Score="2" Body="&lt;p&gt;You can see dust clouds rising from the ground after significant earthquakes.&lt;/p&gt;&#xA;" OwnerUserId="17565" LastActivityDate="2019-08-05T20:02:22.867" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17674" PostTypeId="1" CreationDate="2019-08-06T10:35:51.330" Score="2" ViewCount="275" Body="&lt;p&gt;We know that trees are the most efficient &quot;tool&quot; we have to get CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; out of the air, but the problem is that most of their fixated CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; will naturally reenter the carbon cycle through decomposition.&#xA;Would it be possible to remove this carbon by sinking the trees deep underwater (and possibly putting some rocks / sand on them)? How effective would this be, if at all?&#xA;(I was unable to find any studies on this, if there are please point my to them.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Update: I found a study regarding wood burial on land, for those interested. This might or might not be easier than under water, are there are any field trials either way? &lt;a href=&quot;https://cbmjournal.biomedcentral.com/articles/10.1186/1750-0680-3-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://cbmjournal.biomedcentral.com/articles/10.1186/1750-0680-3-1&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17575" LastEditorUserId="6467" LastEditDate="2020-06-03T22:40:32.680" LastActivityDate="2023-04-11T08:25:13.907" Title="Could we sequester CO$_2$ by dumping forests in deep oceans?" Tags="|climate-change|carbon-cycle|geoengineering|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="17676" PostTypeId="1" CreationDate="2019-08-06T16:39:23.793" Score="1" ViewCount="73" Body="&lt;p&gt;In eastern Ontario, Canada, there's a place where, when walking and stomping, you can hear a hollowness in the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The area is primarily igneous rock with many large boulders, and the spot in question is directly over a very large buried boulder.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The boulder is under 15cm of gravel and 30cm of sand.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are caves in this area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the hollow sound an indication of a cavern/caves, sinkhole, geode or something else?&lt;/p&gt;&#xA;" OwnerUserId="13276" LastActivityDate="2019-08-06T18:32:24.993" Title="Possible cavern?" Tags="|igneous|geodesy|cavern|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17677" PostTypeId="2" ParentId="17676" CreationDate="2019-08-06T18:32:24.993" Score="1" Body="&lt;p&gt;It is extremely unlikely to be a sink hole. They are characteristic of waterlogged limestone country such as is found in Florida. Hollows are sometimes found in flows of igneous rock where there has been volcanic activity. Some hollows are large gas bubbles which were trapped when the rock around them solidified, but probably the most common hollows in volcanic places are lava tubes, formed when a stream of lava solidified in its outer layer while the still molten interior drained away. Your talk of boulders and gravel leads me to believe there has been glacial activity in the area. It isn't possible to say what is causing this hollow sound without a personal, on-the-spot investigation, but I think we can say it's not a sink hole, but might be a volcanic gas hollow or an ancient lava tube. On the other hand it might be something else, it's impossible to say without digging down to it. If the site is limestone and not volcanic, that would put a whole new perspective on it. The caves you refer to might give a clue. It won't be a geode; they are tiny things, usually about the size of a cricket ball and with the hollow half-filled with quartz crystals. Geodes are characteristic of limestone geology, not igneous rock.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-06T18:32:24.993" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17680" PostTypeId="1" CreationDate="2019-08-07T11:44:20.940" Score="3" ViewCount="66" Body="&lt;p&gt;How practice is to map/image the subsurface of the earth using the high energy particles like neutrinos? &#xA;&lt;a href=&quot;https://www.geosci-instrum-method-data-syst.net/special_issue2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.geosci-instrum-method-data-syst.net/special_issue2.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17581" LastActivityDate="2019-08-07T13:11:07.257" Title="Is there any possible future for high energy geophysics? If so how it is going to revolutionize our knowledge about Earth's interior?" Tags="|geology|geophysics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17681" PostTypeId="2" ParentId="17680" CreationDate="2019-08-07T12:58:36.773" Score="2" Body="&lt;p&gt;I don't think neutrinos will be much good for mapping the interior of the Earth, the reason being that they rarely interact with matter and are said to be able to pass through 11 light years of solid lead without being stopped (though I would take that claim with a pinch of salt). However, so many pass through the Earth from the other side that  a tiny number will interact and muons from these interactions have been detected coming upward through the ocean! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Muons seem to be more useful, and have already been used to detect secret chambers in the Great Pyramid. They undoubtedly have applications to volcanology, but don't have the penetration powers of neutrinos. Muons are very transient charged particles which decay in a minute fraction of a second to become electrons or positrons. Because of their ultra-brief lifetime and electric charge they can't penetrate very far, hundreds of metres rather than hundreds of miles, so although they are a useful tool I don't think they will revolutionise geology in general. They might revolutionise the more limited field of geophysics. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cosmic rays are high energy protons and atomic nuclei originating in the sun and other stars, sometimes in supernovae, but their energy is very variable. Most are stopped high in the atmosphere, but their secondary radiations, which include muons, often reach the surface of he Earth. Owing to their randomness and unpredictability, they are unlikely to prove very useful.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-08-07T13:11:07.257" LastActivityDate="2019-08-07T13:11:07.257" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17682" PostTypeId="2" ParentId="17665" CreationDate="2019-08-07T13:31:08.200" Score="3" Body="&lt;p&gt;There was an interesting paper on this for the United States a couple of years ago:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Balch et al (2017) &lt;a href=&quot;https://doi.org/10.1073/pnas.1617394114&quot; rel=&quot;nofollow noreferrer&quot;&gt;Human-started wildfires expand the fire niche across&#xA;the United States&lt;/a&gt;, PNAS, doi: 10.1073/pnas.1617394114&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They estimate that in the coterminous U.S. human-started events account &quot;for 84% of all wildfires and 44% of total area burned&quot;.  There is a marked spatial variation, with lightning-started wildfires occurring mainly in the more sparsely populated western forests.  If you have access, the paper's worth a read, it has lots of interesting figures picking apart the details.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Lcz7m.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Lcz7m.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's worth noting that there are a number of reasons for human-started wildfires, which are could be classed as accidental, deliberate or careless:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Human-started wildfires were caused by a variety of sources, including the US Forest Service-designated categories of equipment use, smoking, campfire, railroad, arson, debris burning, children, fireworks, power line, structure, and miscellaneous fires.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They also note that their data contains this, perhaps not unsurprising, feature:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;There was also a notable mark of American culture on the distribution of wildfires, with the peak day of wildfires occurring on July 4th, concurrent with Independence Day fireworks displays (Fig. 2). Indeed, Americans start over twice as many wildfires on July 4th as any other summer day.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="106" LastActivityDate="2019-08-07T13:31:08.200" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17683" PostTypeId="1" CreationDate="2019-08-07T15:55:09.000" Score="4" ViewCount="384" Body="&lt;p&gt;Most pessimistic scenarios about climate change predicts a global rise of temperature of several Celsius degrees over the course of the 21st century if no action is taken. While such a shift in temperature has many implications such as rising seal levels (due to the melting of ice near the poles) and a mass extinction event, the Earth has recordedly had eras warmer than today in the past, such as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cretaceous&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cretaceous period&lt;/a&gt;. For reminders, Cretaceous is the last geological period before the extinction of dinosaurs, and it had notably higher sea levels and a warmer global surface temperature (4 °C above today's average surface temperature).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assume now that the average surface temperature will rise as predicted by the aforementioned pessimistic scenarios, and that the seal levels will rise drastically.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How would tomorrow's Earth (in this scenario) compare to the Earth of the Cretaceous period ? Would it be in a similar state (besides temperature and sea levels), and perhaps share similar climates around the world, or would various factors I didn't mention (such as the ratio of oxygen in the air) make it very different ?&lt;/p&gt;&#xA;" OwnerUserId="17584" LastActivityDate="2019-08-08T03:24:42.503" Title="If today's Earth becomes warmer, how will it compare to the Earth of the Cretaceous period?" Tags="|climate-change|paleoclimatology|climatology|cretaceous|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17687" PostTypeId="2" ParentId="9891" CreationDate="2019-08-07T22:20:56.037" Score="0" Body="&lt;p&gt;If you want a real-time BOD, COD or coliform sensors look at Proteus Instruments. They can provide real time data even in wastewater applications and almost need no maintenance. The results are pretty impressive. &lt;a href=&quot;http://www.proteus-instruments.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.proteus-instruments.com&lt;/a&gt;. They now have dealers throughout the world. &lt;/p&gt;&#xA;" OwnerUserId="17588" LastActivityDate="2019-08-07T22:20:56.037" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17690" PostTypeId="1" CreationDate="2019-08-08T02:48:21.870" Score="1" ViewCount="98" Body="&lt;p&gt;I am wondering the major differences been an Atmospheric model and a Climate model?&#xA;For example, Regional Atmospheric Modeling System (RAMS) versus Regional Climate Modeling System (RegCM). I recently use the both for 20 years climate simulations, but didn't find why one is called atmospheric and one is climate?&lt;/p&gt;&#xA;" OwnerUserId="3194" LastActivityDate="2019-08-08T02:48:21.870" Title="What is difference between an atmospheric model and a climate model?" Tags="|atmosphere-modelling|climate-models|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="17691" PostTypeId="2" ParentId="17683" CreationDate="2019-08-08T03:24:42.503" Score="3" Body="&lt;p&gt;During the cretaceous the earth was on average 4 degrees warmer, but a 4 degree average results in nearly no change at the equator but a significantly higher rise at the poles, 8 to 15 degrees warmer. Antarctica was not covered in an icecap in the cretaceous period, although smaller ones may have formed periodically. Northern antarctica was largely covered in wet forest. Ecologically you would see wet temperate forest similar to those in australia and south america.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note however warming was not the the only factor different positions of continents leads to a significantly different ocean circulation. Higher sea levels turn lowlands into seas changing rainfall patterns significantly. So the cretaceous is not a great predictor of the near future climate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0012825299000483?via%3Dihub&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source 1&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.cambridge.org/core/journals/geological-magazine/article/leaf-phenology-of-some-midcretaceous-polar-forests-alexander-island-antarctica/5D575D8F4AFDC14B104277422C428F78&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source 2&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2019-08-08T03:24:42.503" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17692" PostTypeId="2" ParentId="239" CreationDate="2019-08-08T09:10:03.527" Score="-1" Body="&lt;p&gt;Here is an archived comment on NASA’s Earth Observatory website, regarding an estimated once in 100-400 years equatorial cyclone – typhoon Varmei in December 2001.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthobservatory.nasa.gov/images/3441/a-rare-cyclone-on-the-equator&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earthobservatory.nasa.gov/images/3441/a-rare-cyclone-on-the-equator&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17595" LastActivityDate="2019-08-08T09:10:03.527" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17697" PostTypeId="1" CreationDate="2019-08-09T04:44:54.323" Score="6" ViewCount="1846" Body="&lt;p&gt;First question on this StackExchange, so here goes...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Overall, reaching high temperatures is dependent on 2 factors:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The (maximum) solar angle in the day. The greater the solar angle, the more insolation is received by the surface and air, allowing higher maximum temperatures assuming no thermal inertia.&lt;/li&gt;&#xA;&lt;li&gt;The length of the day. The longer the day, the more total solar radiation arrives in one 24-hour span, and the shorter the night is to radiate off excess energy, both of which due to the thermal inertia of the atmosphere and ground bias them towards hot temperatures.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;(Again due to thermal inertia, it may be dependent on the day length and solar angle of previous days, though this influence is more minor.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first factor explains why even though at the summer solstice the poles accumulate more solar energy over 24 hours than any other place on Earth (I know I had a source on this. I can't find it, though.), they are still extremely cold as the low solar angle prevents reaching higher temperatures. The second factor explains why even though the equatorial region has the highest average maximum solar angles throughout the year, they don't get especially hot (even in rare desert areas) as the day length is nearly constant throughout the year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ergo, the outer tropics and the subtropics experience the hottest extreme maximum temperatures on Earth. This can be seen in the records for each continent that has a large stretch in that area:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;America (South): 48.9 °C in Rivadavia, Argentina (24.18[3]° S)&lt;/li&gt;&#xA;&lt;li&gt;Africa (South): 50 °C in Dunbrody, South Africa (~33.4° S)&lt;/li&gt;&#xA;&lt;li&gt;Australia: 50.7 °C in Oodnadatta, South Australia (27.54811° S)&lt;/li&gt;&#xA;&lt;li&gt;Africa (North): 51.3/53.5 °C in Ouargla, Algeria (31.95° N)&lt;/li&gt;&#xA;&lt;li&gt;Asia: 53.9 °C in Mitribah, Kuwait (29.81[6]° N)&lt;/li&gt;&#xA;&lt;li&gt;and lastly, America (North): 54.0/54.4/56.7 °C in Furnace Creek, California, USA at a rather high 36.458056° N.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Presumably, the spread in latitudes is due to the geography in those areas being much more suited to the generation of extreme heat than places at the &quot;absolute ideal latitude&quot;. &lt;strong&gt;But what is this absolute ideal latitude? At what point from the equator do the combination of day length and solar angle in summer create the most optimal conditions for extreme heat, other factors being equal?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(My scientific wild ass guess is 30°, but I'd like a more educated answer.)&lt;/p&gt;&#xA;" OwnerUserId="17317" LastActivityDate="2023-09-04T16:22:56.770" Title="What is the most optimal latitude on Earth for the generation of extreme maximum temperatures?" Tags="|meteorology|climate|temperature|geography|astronomy|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17700" PostTypeId="2" ParentId="17697" CreationDate="2019-08-09T10:12:55.517" Score="-2" Body="&lt;p&gt;The places that get the hottest temperatures are close to the equator but not necessarily on the equator. They will be low lying places, perhaps below sea level, and 'enjoying' a continental climate. For the record books, they will also need to be places where a climatologist passes through at the right time to measure it. I see you mention some record temperatures in your question, but I don't remember off hand what the absolute world record temperature is. It won't be far short of 55 C, but what amazes me is how the people who measured such temperatures survived to tell the tale. The atmosphere must have been very dry. From the point of view of human wellbeing, in high humidity temperatures well short of world record don't feel well short, and are almost as dangerous.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-09T10:12:55.517" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17701" PostTypeId="1" AcceptedAnswerId="17704" CreationDate="2019-08-09T12:31:35.913" Score="2" ViewCount="43" Body="&lt;p&gt;We can see that there are &lt;a href=&quot;https://en.wikipedia.org/wiki/Methane_clathrate#Methane_clathrates_and_climate_change&quot; rel=&quot;nofollow noreferrer&quot;&gt;large buildups of methane clathrates&lt;/a&gt; in permafrost regions. This seems different to the buildups of natural gas which &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydraulic_fracturing&quot; rel=&quot;nofollow noreferrer&quot;&gt;fracking&lt;/a&gt; releases, which appear to have just come from escaped gases from oil/coal deposits. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: &lt;strong&gt;Do we know how large deposits of methane clathrates were formed in permafrost regions?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="895" LastActivityDate="2019-08-09T13:48:54.467" Title="Do we know how large deposits of methane clathrates were formed in permafrost regions?" Tags="|fracking|clathrates|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17702" PostTypeId="5" CreationDate="2019-08-09T12:32:13.353" Score="0" Body="&lt;p&gt;Clathrate hydrates, or gas clathrates, gas hydrates, clathrates, hydrates, etc., are crystalline water-based solids physically resembling ice, in which small non-polar molecules (typically gases) or polar molecules with large hydrophobic moieties are trapped inside &quot;cages&quot; of hydrogen bonded, frozen water molecules.&lt;/p&gt;&#xA;" OwnerUserId="895" LastEditorUserId="895" LastEditDate="2019-08-09T17:05:24.047" LastActivityDate="2019-08-09T17:05:24.047" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17703" PostTypeId="4" CreationDate="2019-08-09T12:32:13.353" Score="0" Body="Clathrate hydrates, or gas clathrates, gas hydrates, clathrates, hydrates, etc., are crystalline water-based solids physically resembling ice, in which small non-polar molecules (typically gases) or polar molecules with large hydrophobic moieties are trapped inside &quot;cages&quot; of hydrogen bonded, frozen water molecules." OwnerUserId="895" LastEditorUserId="895" LastEditDate="2019-08-09T17:05:19.293" LastActivityDate="2019-08-09T17:05:19.293" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17704" PostTypeId="2" ParentId="17701" CreationDate="2019-08-09T13:48:54.467" Score="2" Body="&lt;p&gt;Rotting vegetation generates methane, or marsh gas as it is sometimes called. The most obvious method by which clathrates were formed in Arctic regions is that many years ago during summer and autumn, rotting vegetation produced methane, which combined with water at cold temperatures to produce methane ice, otherwise known as clathrates. Extremely cold temperatures are not necessary to form clathrates. They form at the bottom of deep seas, where the temperature even in the tropics is a constant 4 or 5 C. There are huge deposits of clathrates on the deep ocean floor, and there has been talk of exploiting them commercially.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A theory to explain the Permo-Triassic extinction event of 250 million years ago hypothesises that super-eruptions in the Siberian Traps super-volcano raised temperatures enough to release vast quantities of methane from tundras and ocean beds, so that with the additional greenhouse gas the average temperature rose by about 10 C, causing the extinction of nearly 90 percent of all large animals, a greater mass extinction than the better known event at the end of the Cretaceous.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-09T13:48:54.467" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17705" PostTypeId="1" CreationDate="2019-08-09T15:15:34.030" Score="3" ViewCount="143" Body="&lt;p&gt;I am thinking of making a model of swinging building during earthquake and study the methods to minimize the swinging. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So does it even makes sense to approximate the swinging buildings (the base of the building) to simple harmonic motion? if not then what kind of motion does the buildings do.&lt;/p&gt;&#xA;" OwnerUserId="17605" LastActivityDate="2023-02-20T03:58:36.533" Title="Is it reasonable to approximate the swinging building (base of the building) during an earthquake to a simple harmonic motion?" Tags="|earthquakes|seismology|seismic|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17707" PostTypeId="1" CreationDate="2019-08-09T16:11:52.650" Score="5" ViewCount="202" Body="&lt;p&gt;I have run a 60 m refraction seismic line on a mountain summit. The environment was noisy (wind would be the principal agent) and quite difficult to pick first arrivals. It resulted in 800 m/s.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A borehole has shown the profile stands the same after 0.5 m depth of biologic weathering with no fault nor joints to 10 m. Sample taken only at 1 m shows UCS 5 MPa, 10% water absorption which leads to 0.16 porosity, 17.5 kN/m&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt; bulk density. My geologist partner has identified it as rhyolite or andesite, and attributes the low density to weathering action that can extend to several meters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A backhoe couldn't excavate more than 1.0 m. So my concern of rippability expected based on Seismic velocity V&lt;sub&gt;p&lt;/sub&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rock type has been estimated visually and according to a general geologic map (I'm sure it is an igneous rock. It could be also ignimbrite) . All tests results has been shown above, and I'm confident about them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can an igneous rock have a V&lt;sub&gt;p&lt;/sub&gt; of less than 1000 m/s on this situation and need blasting?&lt;/p&gt;&#xA;" OwnerUserId="17444" LastEditorUserId="6298" LastEditDate="2020-05-08T06:14:24.203" LastActivityDate="2022-05-28T11:07:05.747" Title="Can an igneous rock have a Vp of less than 1000 m/s and need blasting to excavate?" Tags="|geology|geophysics|seismology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17708" PostTypeId="1" AcceptedAnswerId="17709" CreationDate="2019-08-09T18:14:20.417" Score="1" ViewCount="91" Body="&lt;p&gt;I am writing a literature review for a project and I have a problem. Namely, I cannot figure out the the condition required for surface-based duct to occur. Literature does not help either. In one of the journals I find:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Surface-based ducts are mostly caused by advection of warm and dry  air over the ocean or land, which creates humidity and temperature inversion.&quot; [1]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And in other&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Surface ducts generally appear in sunny weather with relatively stable atmosphere. At this time, the atmosphere often has a relatively stable temperature inversion layer, and the humidity generally decreases with height.&quot; [2]&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;So one paper says there is humidity inversion while other says that humidity decreases with height. So which is it?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;[1] E.  Dinc  and  O.  Akan, “Beyond-line-of-sight  communications  with  ducting  layer,”IEEECommunications Magazine, vol. 52, no. 10, p. 37–43, 2014.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[2] W. Tang, H. Cha, M. Wei, and B. Tian, “The effect of atmospheric ducts on the propagationof ais signals,”Australian Journal of Electrical and Electronics Engineering, vol. 16, no. 2,pp. 111–116, 2019. [Online]. Available:  &lt;a href=&quot;https://doi.org/10.1080/1448837X.2019.16224918&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1080/1448837X.2019.16224918&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17607" LastActivityDate="2019-08-09T19:44:04.027" Title="Definition of Surface-based atmospheric duct" Tags="|atmosphere|temperature|humidity|inversion|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17709" PostTypeId="2" ParentId="17708" CreationDate="2019-08-09T19:44:04.027" Score="1" Body="&lt;p&gt;Both situations are possible. Normally, the atmosphere gets colder and more rarefied with height, and cold air holds less moisture than warm air. Inversion layers trap the lower air mass closer to the ground, so there is a reversal of what you might normally expect: temperature and humidity rises as you get higher, rather than the normal decrease. Inversion can occur in several ways, for example, if a mass of warm air moves in over a cold surface, an inversion will take place. Bothe statements you quote are correct, but the second one is more usual.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-09T19:44:04.027" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17711" PostTypeId="2" ParentId="17707" CreationDate="2019-08-09T22:54:04.487" Score="1" Body="&lt;p&gt;That seems way too low, even for crustal rocks. Recall: V&lt;sub&gt;p&lt;/sub&gt; = &lt;span class=&quot;math-container&quot;&gt;$\sqrt{[(K + 4G/3)/]}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you have a rough idea of the mineralogy of the rock (you do if you know that it's andesite or rhyolite), you can estimate the bulk modulus (K) and shear modulus (G) with a &lt;a href=&quot;https://pangea.stanford.edu/courses/gp262/Notes/9.EffectiveMediumTheories.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Voigt-Reuss-Hill&lt;/a&gt; average and use a reasonable density value (maybe 2500 kg/m&lt;sup&gt;3&lt;/sup&gt;) to get a reasonable number for V&lt;sub&gt;p&lt;/sub&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/P-wave&quot; rel=&quot;nofollow noreferrer&quot;&gt;This Wikipedia page&lt;/a&gt; has a table of velocities for common rocks that might be helpful.&lt;/p&gt;&#xA;" OwnerUserId="11430" LastEditorUserId="2470" LastEditDate="2020-05-06T13:31:39.513" LastActivityDate="2020-05-06T13:31:39.513" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17712" PostTypeId="2" ParentId="16744" CreationDate="2019-08-10T00:09:04.887" Score="3" Body="&lt;p&gt;This is an interesting question that is maybe a little misguided. Instead of answering your question directly I'd like to draw your attention to some things that might get you to rethink your reasoning.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It turns out that what you're thinking of as the lower mantle (an assemblage of solid phases: mainly bridgmanite + ferropericlase + some other stuff) might not actually extend to the core-mantle boundary (CMB).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In 1942, a mathematician and geophysicist named Keith Bullen came up with a scheme where he labeled the layers of the Earth alphabetically (the crust is A and the inner core is G). In this scheme, the entire lower mantle was designated as a single layer (D). In 1950 Bullen decided to split the D layer -- the top ~1800 km became D' and the bottom ~ 200 km became D''. The D'' layer is associated with a complicated seismic discontinuity, and geophysicists are not entirely in agreement on how to interpret the discontinuity. However, there is general agreement that the seismic signals from the D'' cannot be explained by assuming that it is simply an extension of the lower mantle to the CMB. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My preferred explanation is that D'' represents a thermochemical boundary layer that includes partial melting. A more in-depth explanation can be found &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0031920104002195&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding your question about blobs of iron...It's unlikely that blobs of pure liquid iron would be neutrally buoyant anywhere in the mantle. If you're interested in a more technical explanation of how the density of iron changes with depth (i.e., pressure), you may want to look into finite strain equations of state. The Birch-Murnaghan equation of state is a good place to start.&lt;/p&gt;&#xA;" OwnerUserId="11430" LastEditorUserId="11430" LastEditDate="2019-08-10T05:57:21.057" LastActivityDate="2019-08-10T05:57:21.057" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17713" PostTypeId="2" ParentId="17705" CreationDate="2019-08-10T00:25:19.373" Score="2" Body="&lt;p&gt;By the definition of simple harmonic motion (restoring force proportional to displacement), no. You need to take into account &lt;a href=&quot;http://hyperphysics.phy-astr.gsu.edu/hbase/oscda.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;damping&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11430" LastActivityDate="2019-08-10T00:25:19.373" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17715" PostTypeId="1" AcceptedAnswerId="17722" CreationDate="2019-08-10T03:48:37.377" Score="2" ViewCount="105" Body="&lt;p&gt;We can see that there are &lt;a href=&quot;https://en.wikipedia.org/wiki/Methane_clathrate#Methane_clathrates_and_climate_change&quot; rel=&quot;nofollow noreferrer&quot;&gt;large buildups of methane clathrates&lt;/a&gt; in permafrost regions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Climate scientist James Hansen has &lt;a href=&quot;https://www.theguardian.com/environment/earth-insight/2013/jul/10/james-hansen-fossil-fuels-runaway-global-warming&quot; rel=&quot;nofollow noreferrer&quot;&gt;predicted&lt;/a&gt; that the release of the permafrost methane clathrates could cause runaway climate change. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We know that some have related the &lt;a href=&quot;https://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extinction_event&quot; rel=&quot;nofollow noreferrer&quot;&gt;Triassic Extinction event&lt;/a&gt; to the release of Permafrost Clathrates. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do we know how much methane is stored in the permafrost? Do we know at what temperature it will be released? Can we model the release of methane into the atmosphere in the same way we can model the release of carbon dioxide?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: &lt;strong&gt;Is there evidence to suggest that the release of methane clathrates in permafrost regions will impact climate change?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="895" LastActivityDate="2019-08-11T05:28:17.430" Title="Is there evidence to suggest that the release of methane clathrates in permafrost regions will impact climate change?" Tags="|climate-change|climate-models|methane|clathrates|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17717" PostTypeId="2" ParentId="17715" CreationDate="2019-08-10T09:45:56.017" Score="0" Body="&lt;p&gt;It is very unlikely to happen, but yes, there is evidence that release of methane from permafrost deposits would accelerate climate change. There are also massive deposits of clathrates on the ocean bed. They are mostly in deep ocean where they are kept in cold storage at a permanent 4 C - 5C which never changes, even in the tropics, but some is in shallow temperate seas like the Baltic, where in extreme circumstances melting is not out of the question. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you say, it is suspected that the Permo-Triassic extinction event of 250 million years ago was initiated by super-volcano eruptions in the Siberian Traps which caused the melting of large amounts of clathrates, raising average temperatures by about 10 C. It isn't possible to put an exact figure on the amount of clathrates in the arctic, but the amounts are substantial and enough to accelerate climate warming if they were released in a short span of time, centuries rather than millennia. Oceanic clathrates are far more substantial, and would be worth mining commercially if there was some easy way of getting at them. Articles fight shy of naming a specific melting point for methane ice, perhaps because the structure and therefore the melting point varies with different types,but it is comfortably above the melting point of water ice..&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-10T09:45:56.017" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17722" PostTypeId="2" ParentId="17715" CreationDate="2019-08-11T05:28:17.430" Score="2" Body="&lt;p&gt;Your first two links don't seem to mention clathrates.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.realclimate.org/index.php/archives/2012/01/much-ado-about-methane/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Much ado about methane&lt;/a&gt; says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What methane are we talking about?&lt;br&gt;&#xA;  The largest methane pools that people are talking about are in sediments of the ocean, frozen into hydrate or clathrate deposits (Archer, 2007). The total amount of methane as ocean hydrates is poorly constrained but could rival the rest of the fossil fuels combined. Most of this is unattractive to extract for fuel, and mostly so deep in the sediment column that it would take thousands of years for anthropogenic warming to reach them. The Arctic is special in that the water column is colder than the global average, and so hydrate can be found as shallow as 200 meters water depth.&lt;br&gt;&#xA;  On land, there is lots of methane in the thawing Arctic, exploding lakes and what not. This methane is probably produced by decomposition of thawing organic matter. Methane could only freeze into hydrate at depths below a few hundred meters in the soil, and then only at “lithostatic pressure” rather than “hydrostatic”, meaning that the hydrate would have to be sealed from the atmosphere by some impermeable layer.&lt;br&gt;&#xA;  ...&lt;br&gt;&#xA;  The possibility of a catastrophic release is of course what gives methane its power over the imagination (of journalists in particular it seems). A submarine landslide might release a Gigaton of carbon as methane (Archer, 2007), but the radiative effect of that would be small, about equal in magnitude (but opposite in sign) to the radiative forcing from a volcanic eruption. Detectable perhaps but probably not the end of humankind as a species.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-08-11T05:28:17.430" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17725" PostTypeId="1" AcceptedAnswerId="18887" CreationDate="2019-08-12T10:59:03.203" Score="3" ViewCount="211" Body="&lt;p&gt;A couple of years ago the russians began drilling through about 2 km of ice to reach lake Vostok in Antarctica. It was hoped that they would find living organisms there which had been entombed under the ice for many millions of years. They will be gaining information from the ice cores extracted on the way, but the big discoveries are expected to come when they reach the bottom, predicted to be a vast and deep lake of liquid fresh water.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorDisplayName="user20559" LastEditDate="2021-09-02T11:42:32.437" LastActivityDate="2021-09-02T11:42:32.437" Title="Have russian drilling operations in lake Vostok succeeded yet?" Tags="|antarctica|ice-sheets|lakes|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="17727" PostTypeId="1" AcceptedAnswerId="20667" CreationDate="2019-08-12T18:50:36.813" Score="4" ViewCount="185" Body="&lt;p&gt;Hurricane Harvey (Category 4 hurricane, in August 2017) was a prodigious lightning producer when it hit Houston/SE Texas. But I thought hurricanes don't have much lightning (with the eyewall being the only exception), due to tropical cyclones featuring mostly horizontal shear that inhibits the in-cloud charge separation needed for lightning strikes.&lt;/p&gt;&#xA;" OwnerUserId="6816" LastEditorUserId="2470" LastEditDate="2021-01-10T20:03:37.443" LastActivityDate="2022-07-03T13:11:58.983" Title="Why did Hurricane Harvey have so much lightning associated with it?" Tags="|meteorology|tropical-cyclone|lightning|mesoscale-meteorology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17728" PostTypeId="2" ParentId="17530" CreationDate="2019-08-12T19:03:01.710" Score="1" Body="&lt;p&gt;Salt does sink to the bottom in the oceans. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why? Your question referring to salt. Salt is a solid chemical compound. Take a lump of rock salt of sodium chloride, throw it into the water: it will sink to the bottom. The reason is that the density of sodium chloride with more than 2 g/cm&lt;sup&gt;3&lt;/sup&gt; is higher than the density of seawater less than 1.1 g/cm&lt;sup&gt;3&lt;/sup&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, the salt lump will be dissolved sometime and no longer exist. But then it's no salt anymore. Then there are only fast and somehow moving loose cations and anions in the water.&lt;/p&gt;&#xA;" OwnerUserId="17625" LastActivityDate="2019-08-12T19:03:01.710" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17737" PostTypeId="2" ParentId="17226" CreationDate="2019-08-13T19:32:05.730" Score="1" Body="&lt;p&gt;A 5km impactor would make a very, very global mess.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://users.tpg.com.au/users/tps-seti/spacegd7.html#top&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's a discussion of tsunami formation from asteroid impacts&lt;/a&gt;. It presents numbers for impactor size up to 2km, and posits a rule-of-thumb that indicates a 5km impactor would generate a &lt;em&gt;coherent&lt;/em&gt; wave (one that doesn't dissipate much over great distances) as long as it impacts in water less than 20-30km deep -- in other words, in any ocean on Earth. The tsunamis would propagate right around the globe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://users.tpg.com.au/users/tps-seti/climate.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's a discussion of more general effects from larger impactors&lt;/a&gt;. Fireball radiation from a 5km impactor would ignite flammables within a 600km radius, and the secondary radiation from returning ejecta would cause a firestorm across a &lt;strong&gt;5000km&lt;/strong&gt; radius. Earthquakes and hurricanes would take care of whatever the tsunamis couldn't reach. The skies would be completely dark for months (once the glowing stuff finished landing).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;About our best hope would be for a polar impact, where global atmospheric circulation patterns &lt;em&gt;might&lt;/em&gt; spare the opposite hemisphere the worst effects.&lt;/p&gt;&#xA;" OwnerUserId="13324" LastActivityDate="2019-08-13T19:32:05.730" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17738" PostTypeId="2" ParentId="14259" CreationDate="2019-08-13T20:32:37.560" Score="-3" Body="&lt;p&gt;Reinjection of cooling effluent over decades has got to break down the rock, in fact it probably explodes the rock into tiny pieces which after decades crumbles and lets the lava move...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All of the scholarly industry information available says not to place geothermal plants in seismically active areas...&lt;/p&gt;&#xA;" OwnerUserId="17633" LastActivityDate="2019-08-13T20:32:37.560" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17739" PostTypeId="1" AcceptedAnswerId="17742" CreationDate="2019-08-13T22:55:46.490" Score="1" ViewCount="87" Body="&lt;p&gt;If you visit &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/browse/&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS earthquakes listing&lt;/a&gt;, you get 3 points of information for each earthquake: Location, depth, magnitude. My question is, is there a way to approximate how big of an area is affected? Like if an earthquake happens 20km from San Francisco, how strong does it have to be for someone in SF to be able to feel it? &lt;/p&gt;&#xA;" OwnerUserId="17636" LastEditorUserId="17636" LastEditDate="2019-08-14T15:31:19.253" LastActivityDate="2019-09-12T20:25:09.183" Title="Is there a general equation to know how big of an area is affected by an earthquake?" Tags="|earthquakes|models|mathematics|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17741" PostTypeId="1" CreationDate="2019-08-14T05:39:46.687" Score="10" ViewCount="1278" Body="&lt;p&gt;I often hear that the emission of greenhouse gases (GHGs) by planes is particularly concerning because the emission of GHGs at high altitudes has an even higher impact on global warming than the emission of GHGs at low altitudes (e.g. sea level). I tried to find scientific evidence (e.g. peer reviewed publications, explanations in scholar books) for this claim on the internet but failed. Is the claim stated in the first sentence of my question true? If yes, could you point me towards respected literature? Thanks!&lt;/p&gt;&#xA;" OwnerUserId="17641" LastEditorUserId="111" LastEditDate="2019-08-14T14:08:42.767" LastActivityDate="2019-08-17T05:05:14.337" Title="Impacts of high-altitude emission of greenhouse gases (GHG) compared to sea level GHG emissions" Tags="|climate-change|greenhouse-gases|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17742" PostTypeId="2" ParentId="17739" CreationDate="2019-08-14T10:34:38.043" Score="4" Body="&lt;p&gt;No, there isn't, because the area affected depends on so many factors, some of them unknowable. Magnitude, cause, depth, geology (which may be very variable in different parts of the area) etc. Besides which, the easiest way to tell which areas are affected is to monitor reports from observers. In the final analysis, the data that aid agencies want to know is which areas ARE affected rather than which might theoretically be affected if all relevant factors were known, which they rarely will be.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-14T10:34:38.043" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17743" PostTypeId="2" ParentId="17741" CreationDate="2019-08-14T11:04:58.657" Score="2" Body="&lt;p&gt;Yes, it is true that high altitude emissions of CO2 are more effective as a blanket to keep the Earth warm than the same emissions would be at sea level. On the other hand, emissions at sea level are hundreds or thousands of times more than those emitted by aeroplanes. Although CO2 is heavier than air and has a tendency to sink, convection and diffusion keeps the gases well mixed. The CO2 becomes very dispersed and doesn't separate into layers. Another factor is the vapour trails left by high flying aircraft, which reflect sunlight back into space, and that has a cooling effect.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-14T11:04:58.657" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17745" PostTypeId="2" ParentId="17741" CreationDate="2019-08-14T23:34:51.300" Score="4" Body="&lt;p&gt;I think you may be confusing two separate, but related, issues.  Aircraft emissions at high altitudes are a concern for the ozone layer, because the NOx that is emitted by aircraft can &lt;a href=&quot;https://archive.ipcc.ch/ipccreports/sres/aviation/index.php?idp=23&quot; rel=&quot;nofollow noreferrer&quot;&gt;catalytically destroy ozone&lt;/a&gt;.  Supersonic aircraft fly higher up in the stratosphere than a typical jet, and thus can harm the ozone layer more effectively.  The ozone layer is related to climate change, which is perhaps why you are mixing two issues.  For the most part, &lt;a href=&quot;https://en.wikipedia.org/wiki/Environmental_impact_of_aviation&quot; rel=&quot;nofollow noreferrer&quot;&gt;aircraft greenhouse gas emissions&lt;/a&gt; are not a concern simply due to the altitude they are emitted.  Instead, aircraft GHGs are a concern because they are long-lived in the atmosphere and well-mixed, causing &quot;global&quot; warming.  Furthermore, aircraft emissions are expected to &lt;a href=&quot;https://en.wikipedia.org/wiki/Environmental_impact_of_aviation#Continual_increases_in_travel_and_freight&quot; rel=&quot;nofollow noreferrer&quot;&gt;continue increasing&lt;/a&gt; for decades.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2019-08-14T23:34:51.300" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17748" PostTypeId="1" CreationDate="2019-08-15T11:49:46.300" Score="7" ViewCount="117" Body="&lt;p&gt;We can see that there are &lt;a href=&quot;https://en.wikipedia.org/wiki/Methane_clathrate#Methane_clathrates_and_climate_change&quot; rel=&quot;noreferrer&quot;&gt;large buildups of methane clathrates&lt;/a&gt; in permafrost regions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Climate scientist James Hansen has &lt;a href=&quot;https://www.theguardian.com/environment/earth-insight/2013/jul/10/james-hansen-fossil-fuels-runaway-global-warming&quot; rel=&quot;noreferrer&quot;&gt;predicted&lt;/a&gt; that the release of the permafrost methane clathrates could cause runaway climate change. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We know that some have related the &lt;a href=&quot;https://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extinction_event&quot; rel=&quot;noreferrer&quot;&gt;Triassic Extinction event&lt;/a&gt; to the release of Permafrost Clathrates. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that there are various techniques to extract natural gas from shale and rock. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: &lt;strong&gt;Is it feasible to 'harvest' the Clathrates from the permafrost before they evaporate?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="895" LastEditorUserId="6129" LastEditDate="2020-05-05T11:34:39.603" LastActivityDate="2023-03-19T23:31:23.547" Title="Is it feasible to 'harvest' the clathrates from the permafrost before they evaporate?" Tags="|economic-geology|geoengineering|methane|permafrost|clathrates|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17749" PostTypeId="2" ParentId="17748" CreationDate="2019-08-15T13:16:13.263" Score="-1" Body="&lt;p&gt;No, it's not feasible. They are too dispersed, and any operation to harvest them would be too costly and inefficient, and would amount to vandalism on a gigantic scale. We just have to hope that the vast majority of tundra clathrates will remain un-melted, as will probably be the case. The last time they were melted on a massive scale may well have been the Permo-Triassic extinction event of 250 million years ago.The Arctic tundra is a vast natural wilderness full of valuable wildlife. Any ill-judged operation to remove clathrates would not only be grossly expensive and inefficient, but would have both taxpayers and environmentalists up in arms! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming theories of the Permo-Triassic event are correct, it took the long term eruptions of the Siberian Traps super-volcano to release almost unimaginable quantities of CO2 into the air to trigger the melting of clathrates. Eruptions of super-volcanoes like the Siberian Traps 250 million years ago and the Deccan Traps 66 million years ago make modern volcanic eruptions, even Krakatoa (1883) or Tambora (1815), pale into insignificance.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-15T13:16:13.263" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17750" PostTypeId="1" CreationDate="2019-08-15T20:00:18.447" Score="3" ViewCount="355" Body="&lt;p&gt;I asked &lt;a href=&quot;https://www.quora.com/What-is-the-lowest-latitude-where-each-day-from-the-winter-solstice-to-the-summer-solstice-experiences-more-solar-radiation-and-each-day-from-the-summer-solstice-to-the-winter-solstice-experiences-less-How-do-you&quot; rel=&quot;nofollow noreferrer&quot;&gt;a question with the same meaning on Quora&lt;/a&gt;, but it seems no one got it, so I'm asking it here with a very different wording. I'm actually not sure if this would belong here or on the &lt;a href=&quot;https://astronomy.stackexchange.com/&quot;&gt;Astronomy stack exchange&lt;/a&gt;, as though it deals with the Earth, it is an extremely pure question with almost nothing to do with its atmosphere or complicated innards. Real-world topographic and atmospheric moisture conditions that may affect the results are to be ignored.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For all latitudes outside the tropics, as I'm sure we know, the summer solstice is the date where the sun culminates the highest in the sky, having the highest solar angle and insolation. This angle is 90° at the tropical circles. Closer to the equator, this 90° angle is experienced in 2 Lāhainā noons moving further from the solstice the lower the latitude is until reaching the equinoxes at the equator.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, at &lt;em&gt;all&lt;/em&gt; locations except the equator, the summer solstice is the longest day of the year and the winter solstice the shortest. &lt;strong&gt;Hence, down to a certain latitude within the tropics the summer solstice should &lt;em&gt;still&lt;/em&gt; experience the most total solar energy, as the effect of the longer day would be stronger than that of the lower solar angle.&lt;/strong&gt; As you get closer to the equator, the day length gets more consistent and the angle at the solstice becomes still further from that at the subsolar point, until eventually the solstice no longer receives the most total solar energy and two &quot;humps&quot; emerge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;So, what is that latitude?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: This answer can depend on if the eccentricity of the Earth's orbit is taken into account, in which case the values for the Northern and Southern hemispheres will be different. Answers may choose to take this into account or not (ideally I'd like both).&lt;/p&gt;&#xA;" OwnerUserId="17317" LastActivityDate="2019-08-16T04:31:52.563" Title="What is the lowest latitude for which if the ideal solar energy received each day for a year is graphed, the graph would contain one peak?" Tags="|sun|solar-terrestrial-physics|astronomy|mathematics|insolation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17751" PostTypeId="2" ParentId="16847" CreationDate="2019-08-15T20:59:04.380" Score="1" Body="&lt;p&gt;As Friddy says, if it's not constrained and relatively intact you're going to have issues with pore volume calculations. Generally the saturate-and-dry method, using a soil core, will give you both the water mass and the mass of sediment. Then you'd use the average density of soil (which will depend somewhat on the minerology, and if it's got lots of organic matter--which can be calculated by burning off OM in a 400 C oven) to get at the particle volume. The known volume of the core minus the estimated particle volume would give you the pore volume.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Googling bulk density and particle density should find lots of info on how exactly to do this calculation.&lt;/p&gt;&#xA;" OwnerUserId="16906" LastActivityDate="2019-08-15T20:59:04.380" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17752" PostTypeId="2" ParentId="15083" CreationDate="2019-08-15T21:14:03.943" Score="5" Body="&lt;p&gt;I didn't study tropical soils in any depth, but I've studied quite a bit about wetland soils. In my experience most peaty soils are waterlogged, which would encourage anoxia and prevent decay. Laterites are, from what I've read, usually dry at least part of the year, which would allow bacteria to munch on the organic matter.&lt;/p&gt;&#xA;" OwnerUserId="16906" LastActivityDate="2019-08-15T21:14:03.943" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17753" PostTypeId="2" ParentId="17750" CreationDate="2019-08-16T04:18:10.120" Score="1" Body="&lt;p&gt;Any area south of the northern polar circle will have one peak per day,and the same goes for the southern polar circle any area north of this will have one peak per day,the polar circles is at 66,33 north/south.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The areas whitin the polar circles will have only one peak per year but it will last for half a year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A solar panel will only produce significant power for a maximum 12 hrs even in the area of the midnight sun,This is due to the very low angle of the sun during the &quot;night&quot;,or at the poles it will produce energy for 24 hrs but due to the suns angle a solar panel will produce a lower level of power than if the solar panel was at the equator.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Solar panels will be most effective if placed close to equator and less effective as you move away from equator,The suns rays have to penetrate less atmosphere at equator and a lot more closer to the poles.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6258" LastEditDate="2019-08-16T04:31:52.563" LastActivityDate="2019-08-16T04:31:52.563" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17755" PostTypeId="1" CreationDate="2019-08-16T12:32:35.257" Score="1" ViewCount="112" Body="&lt;p&gt;Most of the discussed geoengineering ideas aim to change the average temperature of the earth instead of trying to control local weather.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Aerostat&quot; rel=&quot;nofollow noreferrer&quot;&gt;Aerostats&lt;/a&gt; can be used to change the local temperature in several ways:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;if covered with reflective material they can create shadow;&lt;/li&gt;&#xA;&lt;li&gt;if covered with dark material they can significantly increase the temperature above the cloud potentially dispersing the cloud;&lt;/li&gt;&#xA;&lt;li&gt;if combined into a structure similar to a solar updraft tower, they can transport dust and humidity to the height where they would not be transported by natural winds and by that either condensate the water or create new clouds.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;With a large enough number of devices like this it should be possible to guide humid air to deserts, or to prevent hurricanes by removing convective available potential energy on their path.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any research about the possibility of controlling the weather with devices like these, or is there some obvious flaw that would make this completely impossible? (Lack of helium is not a good argument, as these aerostats are not meant to lift any additional weight, and are meant to be as large as possible, so could use air heated by the sun).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this is possible, what percentage of earth surface would we need to cover with these devices to counteract CO2 effects? From a rough assessment of incoming radiation vs radiation trapped by human released CO2 it seems to be much smaller than 1%.&lt;/p&gt;&#xA;" OwnerUserId="12934" LastEditorUserId="595" LastEditDate="2019-08-16T15:26:07.180" LastActivityDate="2020-01-13T16:02:50.357" Title="Can aerostats be used for fine-grained control of the weather" Tags="|climate-change|geoengineering|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17756" PostTypeId="2" ParentId="17755" CreationDate="2019-08-16T13:38:41.713" Score="-1" Body="&lt;p&gt;No, the idea is quite impractical. Lack of helium is no obstacle because unmanned balloons, whether tethered or remote controlled could be filled with hydrogen, but to affect the climate you would need millions of them, which is too expensive and impractical. Geo-engineering projects are generally the stuff of science fiction and not practical in the real world. One way climate could be modified on a local scale is to refill places like the dried up Aral Sea with water from the ocean. Apart from other beneficial effects, this would probably produce enough evaporation to affect local rainfall. Rainfall is also locally affected by the presence or absence of trees, so if you want to increase rainfall in arid areas, one way to achieve it is large scale tree planting. That might be difficult in semi-desert environments, but nevertheless it has been done. Sometimes tree roots can reach down to a water table, which is how enormous cypress trees are in some places  able to grow in the sand seas of the Sahara Desert.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-16T13:38:41.713" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="17757" PostTypeId="2" ParentId="6666" CreationDate="2019-08-16T14:37:50.420" Score="-1" Body="&lt;p&gt;Most of the underlying strata beneath the Gulf of Carpentaria seabed is part of &#xA;the Great Artesian Basin (GAB).  It extends out to the Arafura Seabed and west&#xA;of the Torres Strait islands.  It may even extend or connect with paleochannels&#xA;of Papua New Guinea's (PNG's) coastal areas.  Geoscience Australia has maps showing the northern borderline or &quot;country&quot; maritime border areas of GAB.  One could assume that GAB probably goes all the way to the PNG coastline.  CSIRO and Geoscience do not provide maps detailing the geology  under the Arafura Seabed or Torres Strait seabed close to the PNG coastline.&lt;/p&gt;&#xA;" OwnerUserId="17650" LastEditorUserId="17650" LastEditDate="2019-08-16T15:52:43.580" LastActivityDate="2019-08-16T15:52:43.580" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17758" PostTypeId="1" AcceptedAnswerId="17784" CreationDate="2019-08-16T16:33:22.560" Score="2" ViewCount="482" Body="&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/6667/39&quot;&gt;This answer&lt;/a&gt; talks about a &quot;closed basin&quot; that has an outflow to the sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I had previously assumed that &quot;closed basin&quot; meant the same as &quot;endorheic basin&quot;, but that is obviously not the case. What is a &quot;closed basin&quot; in this context?&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-08-19T03:08:02.087" Title="What does a &quot;closed basin&quot; mean in groundwater terms?" Tags="|hydrology|groundwater|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17759" PostTypeId="2" ParentId="17758" CreationDate="2019-08-16T17:19:37.657" Score="0" Body="&lt;p&gt;He didn't say the Great Artesian Basin was a closed basin. What he said was that in the north there was some run off into the Gulf of Carpentaria, but everywhere else the aquifer behaves AS THOUGH it were a closed basin. For it to be an actual closed basin it would need an impervious perimeter which prevented drainage into the Gulf of Carpentaria.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-16T17:19:37.657" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17761" PostTypeId="1" CreationDate="2019-08-16T22:57:18.597" Score="1" ViewCount="264" Body="&lt;p&gt;I have been long looking for the derivations and step by step explanation of Zoeppritz matrix but either internet is full of final versions or I can’t find it...I would be very thankful if anyone can direct me or provide me with derivations. &lt;/p&gt;&#xA;" OwnerUserId="17651" LastActivityDate="2019-11-10T20:19:37.430" Title="Zoeppritz equations derivation" Tags="|geophysics|seismology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17763" PostTypeId="2" ParentId="17741" CreationDate="2019-08-17T05:05:14.337" Score="2" Body="&lt;p&gt;According to this &lt;a href=&quot;https://eng.ucmerced.edu/people/awesterling/ENVE118/exam3_solutions&quot; rel=&quot;nofollow noreferrer&quot;&gt;exam solution from ucmerced.edu&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The residence time of air in the stratosphere is 1-2 years, so that CO2 concentrations in the stratosphere&#xA;  represent those found in the troposphere 1-2 years before. The growth rate of CO2 in the troposphere is&#xA;  1-2 ppmv yr-1, and the time lag for transfer of air from the troposphere to the stratosphere thus results in&#xA;  a 1-2 ppmv difference in concentrations between the two reservoirs.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The charts in &lt;a href=&quot;https://earthscience.stackexchange.com/questions/16364/what-is-the-co2-concentration-by-altitude-and-why&quot;&gt;this question&lt;/a&gt; indicate that CO2 concentration decreases with altitude:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/7whOW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7whOW.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Environmental_impact_of_aviation#Carbon_dioxide_(CO2)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia says&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In 1992, emissions of CO2 from aircraft were estimated at around two percent of all such anthropogenic emissions, and that year the atmospheric concentration of CO2 attributable to aviation was around one percent of the total anthropogenic increase since the industrial revolution, having accumulated largely over just the last 50 years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So it seems that the altitude at which the GHGs are emitted does not make much difference.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-08-17T05:05:14.337" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17764" PostTypeId="1" CreationDate="2019-08-17T07:42:34.653" Score="7" ViewCount="647" Body="&lt;p&gt;The level of CO2 in the atmosphere has risen roughly from &lt;a href=&quot;https://www.co2.earth/&quot; rel=&quot;noreferrer&quot;&gt;300 to 400ppm&lt;/a&gt; over the last 60 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the reliable calculations showing that such a rise has been caused by human activity? I am looking for something like &quot;X millions of tones of kerosene was burnt between 1980 and 2010 which produced Y millions tones of CO2 which effected in additional Z ppm of CO2 in the atmosphere&quot;.&lt;/p&gt;&#xA;" OwnerUserId="17602" LastActivityDate="2019-08-25T20:41:35.323" Title="Has the present rise of CO2 ppm been proved to be caused by human activity?" Tags="|climate-change|co2|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17768" PostTypeId="2" ParentId="17764" CreationDate="2019-08-17T16:51:44.070" Score="6" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zp9ae.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zp9ae.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.epa.gov/ghgemissions/global-greenhouse-gas-emissions-data&quot; rel=&quot;nofollow noreferrer&quot;&gt;US EPA&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some of the carbon goes into the oceans and soil:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LIGbs.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LIGbs.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cumulative contribution to the atmosphere is  the area of the light blue region of this chart.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/BF7m6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BF7m6.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.carbonbrief.org/what-global-co2-emissions-2016-mean-climate-change&quot; rel=&quot;nofollow noreferrer&quot;&gt;CarbonBrief&lt;/a&gt;,  Le Quéré, C. et al. (&lt;a href=&quot;https://doi.org/10.5194/essd-8-605-2016&quot; rel=&quot;nofollow noreferrer&quot;&gt;2016&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2019-08-25T20:41:35.323" LastActivityDate="2019-08-25T20:41:35.323" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17769" PostTypeId="1" AcceptedAnswerId="17946" CreationDate="2019-08-17T17:29:54.883" Score="3" ViewCount="118" Body="&lt;p&gt;The following picture (&lt;em&gt;Painted wall&lt;/em&gt; cliff in the Black Canyon of the Gunnison National Park, Colorado, USA) shows a pegmatite dike: is it possible to tell what was the flow direction? From thin (see below the printed 1 in the picture) to thick (2) or from thick to thin?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aMkPS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aMkPS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7545" LastActivityDate="2019-09-09T15:53:24.683" Title="Is it possible to know what was the flow direction in a pegmatite dike?" Tags="|igneous|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="17772" PostTypeId="2" ParentId="12642" CreationDate="2019-08-17T20:56:49.320" Score="0" Body="&lt;p&gt;Often the cheapest solution is to prevent pollution (not burn leaves, add filters to factories, etc.), but in many cases pollution can be natural, e.g. fine sand from a desert.&lt;br&gt;&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_updraft_tower&quot; rel=&quot;nofollow noreferrer&quot;&gt;Solar updraft towers&lt;/a&gt; are a promising technology that can reduce the pollution near the cities, by creating fast wind which moves the particles to the higher layers of atmosphere. When using the tower only to improve the quality of the air, the greenhouse can be much smaller than the one needed to generate electricity. A small prototype in china have shown sizable improvement in air quality. And here's a link to a &lt;a href=&quot;https://www.researchgate.net/publication/280580726_Performance_and_potential_of_solar_updraft_tower_used_as_an_effective_measure_to_alleviate_Chinese_urban_haze_problem&quot; rel=&quot;nofollow noreferrer&quot;&gt;more detailed study&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="12934" LastActivityDate="2019-08-17T20:56:49.320" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17775" PostTypeId="2" ParentId="17764" CreationDate="2019-08-18T00:26:06.137" Score="3" Body="&lt;p&gt;As per the answer by @KeithMcClary, the atmosphere gets 4 additional billions of tons of carbon from human activity every year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming all that carbon is in the form of CO2, the mass of it will be: 4*(&lt;em&gt;c&lt;/em&gt;+&lt;em&gt;o&lt;/em&gt;*2)/&lt;em&gt;c&lt;/em&gt; where &lt;em&gt;c&lt;/em&gt; is the atomic mass of carbon (12), &lt;em&gt;o&lt;/em&gt; is the one of oxygen (16). This makes roughly 14.7 billions of tons CO2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The total weight of the atmosphere is 5,750,000,000,000,000 tons (from &lt;a href=&quot;https://wgntv.com/2018/06/26/1240332/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;). By simple division we get roughly 2.56 parts per million, which corresponds to 100ppm increase over 60 years (given that annual increase back then was obviously lower than 2.56ppm we have these days).&lt;/p&gt;&#xA;" OwnerUserId="17602" LastActivityDate="2019-08-18T00:26:06.137" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17777" PostTypeId="2" ParentId="17316" CreationDate="2019-08-18T06:27:55.693" Score="2" Body="&lt;p&gt;Distinctive in this case means, does not match well with the first but is explained by the later. This is not the greatest sentence format, but distinct means stands out from. Generally when you refer to something as distinct with respect to X, then it means X is the odd part about it or it stands out from X. In this cased because they are talking about a predictive model and the thing being predicted, then it means it is odd because it does not fit the predictions of the prevailing climate model. &lt;strong&gt;But&lt;/strong&gt; it is also distinct because it is better explained by local factors, for a given value of &amp;quot;local&amp;quot;, which is not normally the case for an event so large. It also might be a reference to more recent research showing the anomaly is likely not global. Combining these two slightly different usages is not great sentence composition but is grammatically correct.&lt;/p&gt;&#xA;&lt;p&gt;In this particular case the regional forcing mechanism is believed to be a large volcano erupting.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="2958" LastEditDate="2021-03-11T10:24:06.073" LastActivityDate="2021-03-11T10:24:06.073" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17778" PostTypeId="2" ParentId="17761" CreationDate="2019-08-18T07:45:40.150" Score="3" Body="&lt;p&gt;The Wikipedia entry for &lt;a href=&quot;https://en.wikipedia.org/wiki/Zoeppritz_equations&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Zoeppritz equations&lt;/strong&gt;&lt;/a&gt; says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A full derivation of these equations can be found in most exploration&#xA;  geophysics text books, such as:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Sheriff, R. E., Geldart, L. P., (1995), 2nd Edition. Exploration&#xA;  Seismology. Cambridge University Press.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="17664" LastEditorUserId="28050" LastEditDate="2019-11-10T20:19:37.430" LastActivityDate="2019-11-10T20:19:37.430" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17779" PostTypeId="1" CreationDate="2019-08-18T07:50:19.243" Score="-1" ViewCount="137" Body="&lt;p&gt;Maybe tornados form from landspouts or gustnados &lt;strong&gt;that get pulled into the mesocyclone&lt;/strong&gt;. Is there some way to look for a correlation between number of tornados on a given day and how conducive conditions are to producing gustnados or landspouts?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: We all know how severe storms form. But some severe storms produce tornados and some dont. Nobody knows why. I am suggesting that maybe the reason some dont is because conditions at that time were not conducive to producing landspouts or gustnados. It might be possible to look at the statistics and see if that is the case. If so then that might help forecasters to predict when tornados are more likely to form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit2: A gustnado is a short-lived, shallow surface-based vortex which forms within the downburst emanating from a thunderstorm.[2] The name is a portmanteau by elision of &quot;gust front tornado&quot;, as gustnadoes form due to non-tornadic straight-line wind features in the downdraft (outflow), specifically &lt;strong&gt;within the gust front of strong thunderstorms&lt;/strong&gt;. As these eddies very rarely connect from the surface to the cloud base, they are very rarely considered as tornadoes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Gustnado&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Gustnado&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Landspouts are a type of tornado which forms during the growth stage of an ordinary cumulus congestus cloud&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Landspout&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Landspout&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit3: changed dust devil to landspout&lt;/p&gt;&#xA;" OwnerUserId="6615" LastEditorUserId="6615" LastEditDate="2020-05-22T09:09:18.577" LastActivityDate="2020-05-22T09:09:18.577" Title="Tornados from landspouts or gustnados" Tags="|tornado|severe-weather|" AnswerCount="2" CommentCount="4" ClosedDate="2020-05-23T21:17:28.670" ContentLicense="CC BY-SA 4.0" />
  <row Id="17780" PostTypeId="2" ParentId="17779" CreationDate="2019-08-18T09:31:52.103" Score="3" Body="&lt;p&gt;Although there is a superficial resemblance between tornados and dust devils, they are very different. There is no connection between the two. I have seen lots of dust devils in reality, but tornados only in videos. Whereas tornados are very large and usually very wet, dust devils are very small and very dry. They occur in deserts and very hot, dry environments. They have enough power to uproot tent pegs and blow down a large tent, but nothing more. I was interested to see that they are fairly common on Mars in what passes for hot weather there. Mars, of course, is a dry, sandy desert, but a very cold one by our standards. The atmosphere is tenuous, but as gravity is only a third of Earth gravity, the dust is lighter and easier to pick up. Hurricanes also have a superficial similarity to tornados, but are vastly larger and produced in a completely different way, but at least they are wet. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-18T09:31:52.103" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17781" PostTypeId="1" CreationDate="2019-08-18T10:39:03.903" Score="3" ViewCount="824" Body="&lt;p&gt;The BBC News article &lt;a href=&quot;https://www.bbc.com/news/world-europe-49345912&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iceland's Okjokull glacier commemorated with plaque&lt;/a&gt; about a dead glacier speaks for itself. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However there is a photo in the article that caught my eye. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It shows mountains in the background and some dry flatland in the foreground. While the foreground is sunlit, some areas are shadowed by clouds, and there is what looks like it could be the apex of a rainbow along the ground with the mountains rising behind it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What might be causing this rainbow-like effect on the ground? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/AWRoL.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Okjokull sat atop the volcano Ok northeast of the Icelandic capital Reykjavik. Photo: JOSH OKUN&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2019-08-18T11:13:29.653" Title="What might be causing this rainbow-like effect on the ground?" Tags="|atmosphere|atmospheric-optics|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17782" PostTypeId="2" ParentId="17781" CreationDate="2019-08-18T11:13:29.653" Score="2" Body="&lt;p&gt;This is very unusual and I've never seen it before, though I have seen other rainbow effects such as double and triple rainbows. What they all have in common is a mist of water droplets lit up by the sun. If you have ever seen a dew drop (and who hasn't) you will have noticed that when the sunlight struck it a pretty coloured light came from it. When you moved your head a little, the light changed colour. This is because white light is bent by the water droplet, and the different wavelengths bend to different degrees, so which colour you see depends on the angle of your eye to the dew drop. It's the same with a rainbow, but in this case there are millions of water droplets. It is also the case with the rainbow-like phenomenon in your photo, but instead of being high in the sky, the water droplets are hugging the ground. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So how could this happen? One possibility that occurs to me is that rain fell on hot ground, and quickly evaporated. As it evaporated into cold air, it condensed into water droplets, so you had this fine aerosol hanging low over the ground. Struck by sunlight, the white light was diffracted in the same way as in a rainbow or a dewdrop or the mist from a garden hose. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-18T11:13:29.653" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17784" PostTypeId="2" ParentId="17758" CreationDate="2019-08-19T03:08:02.087" Score="2" Body="&lt;p&gt;An endorheic basin refers to the surface-water flow. The Great Artesian Basin refers to the groundwater aquifer (the artesian part of the name), not the the Lake Eyre surface water basin, which is endorheic. Part of the land area above the GAB is closed with &lt;em&gt;respect to surface water flow&lt;/em&gt;. Endorheic basins may or may not be closed with respect to groundwater. In fact they may be closed with respect to water in local groundwater flow systems but open with respect to deeper flow systems. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Es6W7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Es6W7.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is common for endorheic basins to be open to groundwater flow. This can occur in a number of ways. The groundwater flow may only be affected by recharge within the basin and not discharge to surface water bodies within the basin. In the case of confined aquifers, it may be essentially separate and unaffected by the surface water or shallower groundwater in the basin but may flow under the basin and exit the other side. Groundwater can discharge to flow-through lakes. These lakes receive groundwater discharge on one side but recharge the groundwater downgradient.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2019-08-19T03:08:02.087" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17785" PostTypeId="1" CreationDate="2019-08-19T07:33:51.317" Score="6" ViewCount="1976" Body="&lt;p&gt;I believe that sand, silt, clay are defined by size. But are they also generated by different processes and from different materials? Alternatively do sand particles ultimately weather to make silt, and do silt particles ultimately weather to make clay?&lt;/p&gt;&#xA;" OwnerUserId="17670" LastEditorUserId="17670" LastEditDate="2019-08-21T05:25:59.233" LastActivityDate="2019-08-22T06:22:25.257" Title="does silt form from sand ; does clay form from silt" Tags="|soil|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17786" PostTypeId="2" ParentId="17785" CreationDate="2019-08-19T08:37:06.173" Score="2" Body="&lt;p&gt;Clay is  a sort of fossilised silt, but differs from silt in that it has a much smaller grain size and in its water content, which gives it plastic qualities. It is formed from the weathering of rocks, and as rocks vary, so does the colour and chemical composition of clay. The particles are deposited in calm water such as a lake. Although clay has a silicate content and in part could include the weathering of sandstone rocks, it couldn't be formed entirely from silicon dioxide sand. Although the weathering of sand and sandstone make a contribution to the mix that forms clays, it can't be their sole constituent. It is conceivable that silt particles could form a mudstone and weathering could further reduce particle size so that it became a clay.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-19T08:37:06.173" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17788" PostTypeId="1" CreationDate="2019-08-19T10:38:54.267" Score="1" ViewCount="110" Body="&lt;p&gt;How impactful is climate change scientific research on climate change policy?&#xA;Are there any statistics which help to visualise the effectiveness of new scientific findings or new technology innovation inducing a change in government policy to help kerb climate change?&#xA;Even any papers regarding this will be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="17673" LastEditorUserId="17673" LastEditDate="2019-08-20T03:59:21.527" LastActivityDate="2019-08-20T03:59:21.527" Title="Climate change research and policy" Tags="|climate-change|" AnswerCount="2" CommentCount="7" ClosedDate="2019-08-20T18:43:31.493" ContentLicense="CC BY-SA 4.0" />
  <row Id="17790" PostTypeId="2" ParentId="17788" CreationDate="2019-08-19T17:40:56.093" Score="-6" Body="&lt;p&gt;Climate change research has a big impact on government policy with some governments, but not all. Governments are in a tricky position, on the one hand they would like to appease climate change hysteria and play it safe, on the other hand they don't want to handicap their industries, lower national prosperity and raise unemployment by fulfilling the demands of the greens and taking drastic steps to reduce CO2 emissions. There is no doubt at all that climate change is happening, because it has always been happening. At present we are on a warming trend which began about 12,000 years ago. At present, atmospheric CO2 levels are about 400 parts per million and rising, but they have been a lot higher within historical times, and far higher within the last half-a- billion years. An added complication is that it is impossible to distinguish between anthropogenic CO2 and CO2 from natural sources, and there are many other factors which complicate the issue. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Take glacial retreat for example. There is scientific consensus that most glaciers are melting and on the retreat, but a surprising number, hundreds rather than dozens, are advancing. This is not to say there is no global warming, scientific opinion is that global warming is a reality and that rising CO2 levels will exacerbate it, but by how much is uncertain. A further complication is that increased CO2 levels promote increased plant growth (by plant growth I mean everything from rainforest, peat bogs and agricultural crops to marine cyanobacteria, algae and phytoplankton),so to some extent rising CO2 levels are self-correcting. There is a danger, however, that this self-correction mechanism could be swamped if CO2 levels rise too quickly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing you can be sure of is that the reductions in CO2 emissions which environmentalists tell us are necessary will not be met or even almost met by the major emitters. Regardless of whether countries like UK meet their targets or not, major industrial countries like USA, China, Russia and India won't. That is a fact that people will just have to get used to, and if the consequences are catastrophic (lets hope they won't be) we will just have to live with them. Perhaps the start of the next ice age will rescue us; despite Milankovitch cycles they are not entirely predictable. There was a 450-year Little Ice Age, beginning about AD 1350 and ending about AD 1800, which no one can explain. Scientific advances like electric vehicles will help, but it will take a major breakthrough like the perfection of fusion reactor power stations to make a really important difference.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-19T17:40:56.093" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="17792" PostTypeId="2" ParentId="17788" CreationDate="2019-08-19T18:45:13.060" Score="1" Body="&lt;p&gt;Climate change is a complicated subject which is difficult to predict with accuracy.   The IPCC's predictions at least since their 3rd report (TAR) appear to be quite good, but good over the first few years or decade and a half vs good for predictions up to 2100 remains inexact and perhaps unclear.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Governments (many not all) do rely in the scientific research of the IPCC both to anticipate coming changes and determine action, but these are difficult questions, as a global effort is required to reduce the greenhouse gas footprint, and individual nations can only control their own policies.   Even if we know, 100%, the future effects of climate change, it would still be a difficult transition away from fossil fuels towards a more climate neutral approach because (If I may borrow the word from Al Gore), fossil fuels are convenient.   They're relatively easy, especially for nations that don't need to import them and they're economically viable. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That's a general outline.   The scientific predictions are important because without them, government leaders would be making policy decisions blind (as opposed to making them based on imperfect projections), and imperfect is better than blind.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are similar predictions/estimates made across the gamut in political policy decisions.  Estimates are made on future costs of government programs and on tax policies and national debt, or trade.   We're always trying to make mathematical or scientific estimates which, in theory, help leaders make predictions for the future.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ofcourse, sometimes, you get leaders who don't care, who don't listen to the forecasts, climate change or economic indicators.  Politics is a messy game.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Are there any statistics which help to visualise the effectiveness of&#xA;  new scientific findings or new technology innovation inducing a change&#xA;  in government policy to help kerb climate change?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I don't know where you'd find such statistics and I've never seen any.    Statistics can be a tricky business with a long game approach like this one.   There's a lot of factors.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2019-08-19T18:50:27.970" LastActivityDate="2019-08-19T18:50:27.970" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17793" PostTypeId="2" ParentId="17785" CreationDate="2019-08-20T00:52:31.187" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://www.jstor.org/stable/30061452?seq=10#metadata_info_tab_contents&quot; rel=&quot;nofollow noreferrer&quot;&gt;Factors Influencing the Rounding of Sand Grains&lt;/a&gt;, &#xA;Victor Ziegler (1911) says that collisions of small sand grains in water are effectively cushioned by the viscosity of water, so that sand grains will not be made smaller than 0.75 mm. by water action. Wind action can erode them smaller because of the lower viscosity of air. (I don't know whether this theory is still accepted today.)&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-08-20T00:52:31.187" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17794" PostTypeId="2" ParentId="17785" CreationDate="2019-08-20T03:44:57.113" Score="4" Body="&lt;p&gt;Sand to silt is a physical process, silt to clay is most often a chemical process. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sand and larger rocks are physically weathered to form silt, everything from &lt;a href=&quot;https://www.tandfonline.com/doi/abs/10.1080/00167617508728913&quot; rel=&quot;nofollow noreferrer&quot;&gt;frost wedging&lt;/a&gt; to simple &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0169555X97000846?via%3Dihub&quot; rel=&quot;nofollow noreferrer&quot;&gt;abrasion&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clay is a different creature entirely, for a start there is a disagreement about the definition of clay across disciplines. Several disciplines of geology use different size based definitions.  Clays can for from &lt;a href=&quot;https://link.springer.com/chapter/10.1007%2F978-3-642-85916-8_2&quot; rel=&quot;nofollow noreferrer&quot;&gt;physical or chemical processes&lt;/a&gt; depending on the &lt;a href=&quot;https://royalsocietypublishing.org/doi/abs/10.1098/rsta.1984.0026&quot; rel=&quot;nofollow noreferrer&quot;&gt;type of clay&lt;/a&gt;. Most often clay form from the &lt;a href=&quot;https://egsp.lyellcollection.org/content/21/1/29&quot; rel=&quot;nofollow noreferrer&quot;&gt;hydrolysis&lt;/a&gt; of tiny mineral particles. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="6467" LastEditDate="2019-08-20T12:28:41.710" LastActivityDate="2019-08-20T12:28:41.710" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17795" PostTypeId="1" CreationDate="2019-08-20T14:49:18.537" Score="3" ViewCount="54" Body="&lt;p&gt;I have a hypothetical situation, and I am specifically interested in how this situation would affect the weather.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have asked this question elsewhere, however I feel that nobody with any expertise on weather systems or meteorology has responded to my question.  So I was hoping that someone here could help me out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The hypothetical situation is as follows:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Positioned above a large landmass on Earth (America or Russia for instance) is an immense flat disc, at least two thousand miles in diameter. It is thin and has comparatively little weight or mass, but it is also opaque and does not let any light through.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This flat disc is positioned roughly 40-50 miles away from the surface of our planet, and the object is locked in with the rotation of the Earth so that it says above the landmass. This disc blocks any sunlight hitting it from reaching the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In such a hypothetical situation, what effects would this disc have to our atmosphere and weather?&lt;/p&gt;&#xA;" OwnerUserId="17682" LastEditorUserId="17682" LastEditDate="2019-08-20T16:12:38.137" LastActivityDate="2019-08-20T16:12:38.137" Title="Hypothetical: an immense disc blocks sunlight, how does this affect the weather?" Tags="|meteorology|hypothetical|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17797" PostTypeId="1" CreationDate="2019-08-20T17:19:59.510" Score="3" ViewCount="163" Body="&lt;p&gt;The ocean soaks up about 90 percent of the heat of climate change, because of ocean heating. When using &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiative_forcing#Climate_sensitivity&quot; rel=&quot;nofollow noreferrer&quot;&gt;the formula of Svante Arrhenius&lt;/a&gt; to calculate forcing due to atmospheric &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\Delta F=\alpha\ln(\frac{C}{C_0})\quad[W/m^2]$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and the formula&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\Delta T_s = \lambda \Delta F\quad[K]$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;the steady-state surface temperature become higher than the measured temperature of global warming. I would like to find out how to correct Arrhenius formula because of the cooling effect from the oceans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it possible to do that based on the estimate that 90 % of the heat is accumulated in the 70 % of the surface that is water?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\alpha=5.35,\,\lambda=0.8,\,C=410,\,C_0=280$&lt;/span&gt; gives&lt;br&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$\Delta T=0.8\times5,35\times \ln(\frac{410}{280})\approx 1.6^oK$&lt;/span&gt;&#xA;For the period 1850-2019.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Arrhenius formula gives temperature raise &lt;span class=&quot;math-container&quot;&gt;$1.6$&lt;/span&gt; K and measured temperature raise is about &lt;span class=&quot;math-container&quot;&gt;$1.1$&lt;/span&gt; K which gives a factor of correction &lt;span class=&quot;math-container&quot;&gt;$\approx 0.7$&lt;/span&gt;.&lt;/p&gt;&#xA;" OwnerUserId="16809" LastEditorUserId="16809" LastEditDate="2019-09-14T20:29:40.853" LastActivityDate="2019-09-14T20:29:40.853" Title="Cooling effect from the oceans in global warming" Tags="|climate-change|oceanography|temperature|co2|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17799" PostTypeId="1" AcceptedAnswerId="17800" CreationDate="2019-08-20T21:10:05.730" Score="3" ViewCount="52" Body="&lt;p&gt;So graphing the ocean floors using sonar is not anything new. But what are the limits to sonar?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would it be possible for a regular sonar device to emit sounds that are strong enough to penetrate through polluted waters? And if they can, how much pollution is needed to block the sonar completely? And by pollution I mean plastic waste (bottles, bags, etc).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, would highly populated waters be a problem? I'm talking about corals, fish, algae, and others. I'm pretty sure just one fish wouldn't do much, but what about a whale? Or a swarm of fish?&lt;/p&gt;&#xA;" OwnerDisplayName="user17688" LastActivityDate="2019-08-20T21:45:03.593" Title="Can a sonar used to graph the ocean floors detect through polluted and highly populated waters?" Tags="|oceanography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17800" PostTypeId="2" ParentId="17799" CreationDate="2019-08-20T21:45:03.593" Score="2" Body="&lt;p&gt;Using sonar to map the ocean floor is not usually affected by pollution or by the occasional fish, if it's a normal herring or cod sized fish. Plastic pollution usually floats or sinks so it isn't a problem. A fish the size of a basking shark would show up on the sonar, but it wouldn't be a problem. Large shoals of fish also show up, but it would have to be a very large shoal indeed to interfere with mapping the ocean floor. There are seasonal shoals large and continuous enough to do this, but only at certain times of the year in a very few locations where they are on migration in their billions. I have never heard of one causing problems for a vessel whose mission was to map the ocean floor or search for a sunken ship. Sonar is sometimes used by trawlers to search for shoals of fish.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-20T21:45:03.593" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17803" PostTypeId="1" CreationDate="2019-08-21T14:38:26.140" Score="2" ViewCount="238" Body="&lt;p&gt;What is the estimated total mass of organic carbon plus elemental carbon (defined here as all carbon in any chemical form, minus carbon dioxide, inorganic carbonates, and other fully oxidized carbon species such as urea and cyanates) in or on the Earth's crust, oceans, surface waters, and atmosphere?&lt;/p&gt;&#xA;" OwnerUserId="17694" LastEditorUserId="17694" LastEditDate="2019-08-21T16:58:58.353" LastActivityDate="2019-08-21T17:03:13.193" Title="What is the total mass of organic carbon on Earth?" Tags="|climate-change|carbon-cycle|environmental-protection|carbon|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17804" PostTypeId="2" ParentId="17803" CreationDate="2019-08-21T17:03:13.193" Score="-1" Body="&lt;p&gt;You could never have an estimate which was anything more than a wild guess masquerading as an estimate. To estimate the carbon in living vegetable matter alone would be hard enough, and result in a very inaccurate approximation, but to include the quantity in the Earth's crust as well could only be a wild and very inaccurate guess. The exact quantity of all the Earth's oil reserves, coal, peat, limestone and other carbonates isn't known with any precision, then there are oil shales,tar sands, asphalt lakes,clathrates and God knows what else,but the great thing about a sufficiently large, wild guess is that no one could ever prove you wrong, especially as on a few occasions and by sheer chance, guesses turn out to be right!  But it is an estimate, presumably an accurate one that you asked for, and that is impossible. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-21T17:03:13.193" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17805" PostTypeId="1" CreationDate="2019-08-21T20:37:16.940" Score="2" ViewCount="263" Body="&lt;p&gt;I just want see which cities are on the same latitude as others. Please recommend latitude-preserving projection that's free and online. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hIwT6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hIwT6.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user17042" LastActivityDate="2019-08-25T17:19:12.837" Title="What map projection preserves latitude?" Tags="|projection|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="17806" PostTypeId="2" ParentId="17805" CreationDate="2019-08-21T22:24:30.187" Score="0" Body="&lt;p&gt;Mercator's projection shows lines of latitude accurately in so far as all towns and geographical features at the same latitude will be shown as such by the horizontal lines on a Mercator's projection, but inaccuracy comes in when you look at the distance between lines of latitude as they move away from the equator. The distance between successive lines becomes increasingly extended, which exaggerates the size of northerly countries like Britain and minimises the size of countries on or near the Equator. To look at a Mercator's map, you'd think Borneo, which is on the Equator, was about the same size as Ireland, but it is actually about three times the size of Great Britain. Greenland appears to be as large as Africa, yet it is actually about the size of Algeria. However, all towns and features shown to be at the same latitude are at the same latitude, which is what you say you are looking for.. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-21T22:24:30.187" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17807" PostTypeId="1" CreationDate="2019-08-22T00:50:38.000" Score="1" ViewCount="2972" Body="&lt;p&gt;If two adjacent tectonic plates are moving in the same direction, is there significant interaction at the boundary? Is it just a convergent boundary if one moves faster and &quot;catches up&quot; with the other? The boundary types typically shown include Transform, Convergent, Divergent, and &quot;Other&quot; (for when there are scattered microplates, or when other complex/compound interactions are occurring)&lt;/p&gt;&#xA;" OwnerUserId="17697" LastActivityDate="2019-09-09T16:19:17.413" Title="If two adjacent tectonic plates are moving in the same direction, is there significant interaction at the boundary?" Tags="|geology|plate-tectonics|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17809" PostTypeId="1" CreationDate="2019-08-22T02:38:17.423" Score="1" ViewCount="78" Body="&lt;p&gt;My family and I want travel somewhere with polar night. I looked up  &lt;a href=&quot;https://www.timeanddate.com/sun/norway/tromso?month=12&amp;amp;year=2019&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tromsø, Norway&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&quot;Down all day&quot; beneath means 24 h darkness, no sun and thus no sun-light. Right? &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;But if  no sun and sun-light, why's there still &lt;a href=&quot;https://www.timeanddate.com/astronomy/different-types-twilight.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;twilight&lt;/a&gt;?  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/B9H9H.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/B9H9H.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user17042" LastActivityDate="2019-08-26T18:42:17.580" Title="What does it mean when polar nights have twilight?" Tags="|light|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17810" PostTypeId="2" ParentId="17809" CreationDate="2019-08-22T03:04:00.933" Score="2" Body="&lt;p&gt;Twilight occurs when the sun is just slightly below the horizon. You cannot see the sun but light will still be available due to atmospheric processes. The different stages of twilight depend on the angle of the sun to the horizon leading to different degrees of darkness. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Down all day just means that the sun will never pass the horizon. But twilight may still occur since around midday the sun will still be close to the horizon. &lt;/p&gt;&#xA;" OwnerUserId="681" LastActivityDate="2019-08-22T03:04:00.933" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17811" PostTypeId="2" ParentId="17809" CreationDate="2019-08-22T04:41:27.393" Score="2" Body="&lt;p&gt;From an human eye perspective.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Civil twilight=you will be able to read a newspaper.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nautical twilight=you will be able to see the contours of mountains and the brightest stars will be visible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Astronomical twilight=you will no longer be able to see the contours of mountains and the atmosphere will have a very dark color,lots of stars are visible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Night=the sky is black and all of the stars are visible you will need additional light to be able to find your way(all of this is for areas with no manmade illumination)&lt;/p&gt;&#xA;" OwnerUserId="6258" LastActivityDate="2019-08-22T04:41:27.393" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17812" PostTypeId="2" ParentId="17807" CreationDate="2019-08-22T07:54:30.570" Score="0" Body="&lt;p&gt;There has to be some kind of interaction for seismologists and geologists to detect and trace the location of the boundaries, so it all hinges on what you mean by significant. There must be some difference in movement for one plate to break away from another in the first place. In the situation you describe, it is extremely unlikely that the movement of the two plates would coincide exactly, though it might seem to for a while when the unequal motion was temporarily halted by friction. This would build up an elastic tension between the two surfaces which would one day have to be released by slippage. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-22T07:54:30.570" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17813" PostTypeId="2" ParentId="17805" CreationDate="2019-08-22T09:23:26.393" Score="4" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mPxz8.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mPxz8.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A cylindrical projection with a vertically oriented cylinder which is tangent to the Equator produces a map that you are looking for. In this kind of map projection, all the points on the same latitude (all the points that are at the same distance from Equator) stays on the same horizontal line on the projected map.&lt;/p&gt;&#xA;" OwnerUserId="13741" LastActivityDate="2019-08-22T09:23:26.393" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17814" PostTypeId="1" CreationDate="2019-08-22T10:10:07.653" Score="3" ViewCount="96" Body="&lt;p&gt;I know from many years of personal experience in the Malaysian rainforest (Sarawak, Sabah and Peninsular Malaya) that it is not inflammable. Dayaks and aborigines cultivate small patches of shifting cultivation called &lt;em&gt;ladangs&lt;/em&gt;, but the trees have to be felled and dried in the sun before they can be burned. No precautions are necessary to prevent the surrounding rainforest from catching fire. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yet, I often hear of rainforest being burned on a vast scale, particularly in Brazil, and wonder how it can be rainforest if it burns so easily. Are these inflammable forests really rainforests, or are they being confused with monsoon forests which are dry for a large part of the year? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another type of vegetation in Malaysia is what we call secondary jungle and Malays call &lt;em&gt;belukar&lt;/em&gt;. It is a kind of thorny scrub which soon springs up on abandoned ladangs, and is probably easier to slash and burn than primary rainforest. Left for about 60 years, &lt;em&gt;belukar&lt;/em&gt; becomes primary rainforest again.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="6129" LastEditDate="2020-05-08T06:47:17.137" LastActivityDate="2020-05-08T06:47:17.137" Title="Are these tropical forests burning in Brazil and elsewhere really rainforests?" Tags="|forest|rain|deforestation|" AnswerCount="0" CommentCount="5" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17815" PostTypeId="2" ParentId="12601" CreationDate="2019-08-22T18:42:45.527" Score="0" Body="&lt;p&gt;I've never heard of rivers being classified by width before, especially as the same river can vary tremendously in different parts of its length. They are usually classified by length or by volume of water delivered to the sea. There are two contenders for longest: Amazon and Nile. It is generally agreed that the Amazon delivers the greatest volume of water, and it is usually held that the Nile is the longest. &quot;Rivers&quot; a few metres wide or less are usually referred to as streams or brooks. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for suitability for ships, depth is more important than width, and where a river has the depth it usually has the width as well. There is no river that can't be bridged, but perhaps you mean bridged in a single span. There are suspension bridges which span about a mile, rather more than your 100 metres! You don't say how you would choose the spot where the width of the river would be measured from. I doubt whether your scheme of classifying rivers by width is practical. Perhaps classifying them by navigability would be better.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-08-22T18:49:59.683" LastActivityDate="2019-08-22T18:49:59.683" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17816" PostTypeId="1" AcceptedAnswerId="17818" CreationDate="2019-08-22T20:58:14.090" Score="5" ViewCount="235" Body="&lt;p&gt;In the image below, taken from Google Maps satellite view, between Svalbard and Greenland there is what looks like a massive crevasse, chasm, crack, &amp;amp;c. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is it? Should I be worried?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gvG90.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gvG90.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17701" LastActivityDate="2019-08-22T21:42:56.497" Title="What is the chasm in the Arctic on Google satellite map?" Tags="|mapping|arctic|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17817" PostTypeId="2" ParentId="17534" CreationDate="2019-08-22T21:34:35.283" Score="1" Body="&lt;p&gt;In the journal Nature, &quot;&lt;a href=&quot;https://www.nature.com/articles/d41586-018-03036-4&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geoengineer polar glaciers to slow sea-level rise&lt;/a&gt;&quot;  professor of climate change John C. Moore and three colleagues (a geoscientist, an applications scientist, and a glaciologist) propose exploring three more feasible methods, arguing:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Without coastal protection, the global cost of damages could reach&#xA;  US$50 trillion a year. Sea walls and flood defences cost tens of&#xA;  billions of dollars a year to construct and maintain.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;At this price, geoengineering is competitive.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The proposals are:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Block warm water: Build 100-meter high berms to protect the outlets of key glaciers &lt;/li&gt;&#xA;&lt;li&gt;Support ice shelves: Similar to No. 1, but buttressing key Antarctic ice shelves at the sea end to keep them from collapsing.&lt;/li&gt;&#xA;&lt;li&gt;Dry subglacial streams: Divert the water currently trickling through and then lubricating the bottoms of glaciers, reducing melting and helping lock them into place.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Any project would require a massive industrial infrastructure in an inhospitable environment supported by billions of dollars in planning, development, and operation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Moving ice mass inland by pumping, as you propose, would also require a method to melt ice in a sub-zero environment, capture and store the meltwater, and then transport the meltwater tens or hundreds of miles uphill across a frozen landscape.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KIUh9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KIUh9.png&quot; alt=&quot;cross-section of Antarctica&quot;&gt;&lt;/a&gt;&#xA;(Cross-section from &lt;a href=&quot;https://www.researchgate.net/publication/259089264_Exploration_of_Antarctic_Subglacial_Aquatic_Environments_Environmental_and_Scientific_Stewardship&quot; rel=&quot;nofollow noreferrer&quot;&gt;Exploration of Antarctic Subglacial Aquatic Environments: Environmental and Scientific Stewardship&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for pumping seawater into low-lying land areas to counter sea-level rise, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/10830/hypothetically-would-digging-a-big-trench-from-the-ocean-and-flooding-desert-ar/10832#10832&quot;&gt;that's also infeasible&lt;/a&gt;: It would require a constant pumped flow equivalent to some of the world's largest rivers, and even then some of that effort would be undone by evaporation.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2019-08-22T21:34:35.283" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17818" PostTypeId="2" ParentId="17816" CreationDate="2019-08-22T21:42:56.497" Score="10" Body="&lt;p&gt;You probably realise this, but you're not seeing that directly from satellite photos. Google Earth (or the &quot;satellite&quot; view in Google Maps) shows direct imagery on land, but underwater it shows a hillshaded view of bathymetry. So you're looking at the shape of the seabed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With that said, I think this is the nothernmost part of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mid-Atlantic_Ridge&quot; rel=&quot;noreferrer&quot;&gt;Mid-Atlantic Ridge&lt;/a&gt;, possibly the part known as the &quot;Mohns Ridge&quot;. You'll see a similar line, coming and going, all the way from here down to the middle of the South Atlantic. There's a deep valley with mountains on either side. It's the boundary between two tectonic plates, where new seabed is slowly created as the Atlantic widens.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No, you should not be worried about it :-)&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-08-22T21:42:56.497" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17819" PostTypeId="2" ParentId="12601" CreationDate="2019-08-22T21:52:15.937" Score="2" Body="&lt;p&gt;I'm not aware of any classification of rivers by width, per se.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But something that you might find of interest is the classification of European inland waterways, as per &lt;a href=&quot;https://en.wikipedia.org/wiki/Classification_of_European_Inland_Waterways&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; or this map: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.unece.org/fileadmin/DAM/trans/main/sc3/European_inland_waterways_-_2012.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.unece.org/fileadmin/DAM/trans/main/sc3/European_inland_waterways_-_2012.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(beware large PDF map, don't try to open on a cellphone)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are a range of classifications that dictate what size of vessel is permitted on (or possibly what size of vessel is guaranteed to be able to navigate) that part of that waterway. These are nearly all concerned with the size of the vessel, and so will relate to the width, depth, and bend radii of the rivers, as well as the minimum bridge clearance and perhaps some other considerations.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-08-22T21:52:15.937" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17820" PostTypeId="2" ParentId="17764" CreationDate="2019-08-22T22:53:13.977" Score="7" Body="&lt;p&gt;Possibly the strongest human &quot;fingerprint&quot; on rising CO2 levels comes from the changing ratio of carbon isotopes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically, there are three isotopes of carbon -- carbon atoms with varying weights of neutrons -- carbon-12, carbon-13, and carbon-14. Carbon-12 and carbon-13 are stable and make up most of of the carbon in living things and the atmosphere. (I'm paraphrasing the &lt;a href=&quot;https://www.acs.org/content/acs/en/education/whatischemistry/landmarks/keeling-curve.html#isotopic-fingerprints-and-the-carbon-cycle&quot; rel=&quot;noreferrer&quot;&gt;American Chemical Society discussion&lt;/a&gt;.) Carbon-14 is (mainly) created when cosmic rays hit nitrogen atoms in the atmosphere; it's less statable and has a half-life of 5,730 years. All three forms behave pretty much the same in chemical reactions and the environment. Plants and animals use carbon as building blocks and accumulate all three isotopes in their structures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Things that are alive now accumulate carbon isotopes in the same ratio as they're available in the environment; when plants or animals die, they stop accumulating carbon carbon, and the carbon-14 in their structures breaks down according to its half-life, which is how researchers do carbon dating of ancient materials.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What this means is that very old concentrations of carbon -- such as oil and coal -- contain little or no carbon-14, just carbon-12 and carbon-13. When you burn these materials, the combustion process forms carbon dioxide, and the carbon in those CO2 molecules will be carbon-12 and carbon-13. Thus, you can sample the atmosphere, analyze the mix of isotopes, and determine how much of the CO2 comes from fossil sources.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The rise in CO2 is unambiguously caused by human activity, principally&#xA;  fossil-fuel burning. This is clear from the numbers: We know how much&#xA;  fossil fuel is converted into CO2 each year and emitted into the&#xA;  atmosphere.&#xA;  -- Scripps Institution of Oceanography geochemist Ralph Keeling&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Sources: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.esrl.noaa.gov/gmd/ccgg/isotopes/&quot; rel=&quot;noreferrer&quot;&gt;The Basics: Isotopic Fingerprints&lt;/a&gt;, National Oceanic and Atmospheric Administration Earth System Research Laboratory&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://scripps.ucsd.edu/programs/keelingcurve/2018/09/19/is-the-current-rise-in-co2-definitely-caused-by-human-activities/&quot; rel=&quot;noreferrer&quot;&gt;Is the Current Rise in CO2 Definitely Caused by Human Activities?&lt;/a&gt;, on the Keeling Curve website&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.acs.org/content/acs/en/education/whatischemistry/landmarks/keeling-curve.html#isotopic-fingerprints-and-the-carbon-cycle&quot; rel=&quot;noreferrer&quot;&gt;The Keeling Curve: Carbon Dioxide Measurements at Mauna Loa&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2019-08-22T22:53:13.977" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17822" PostTypeId="1" AcceptedAnswerId="17824" CreationDate="2019-08-23T19:03:57.380" Score="4" ViewCount="1691" Body="&lt;p&gt;Many times we see in articles that the Amazon rainforest creates 20% of the oxygen of the world . Even french president Macron stated this in a tweet &lt;a href=&quot;https://twitter.com/EmmanuelMacron/status/1164617008962527232&quot; rel=&quot;nofollow noreferrer&quot;&gt;Macron tweet&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to this &lt;a href=&quot;https://www.google.com/search?ei=9TZgXYnIMt-95OUPmoWjoAU&amp;amp;q=amazonas%20size&amp;amp;oq=amazonas%20size&amp;amp;gs_l=psy-ab.3..0i19j0i22i30i19l4.51992.55863..56263...1.4..1.614.2986.8j4j1j0j1j2......0....1..gws-wiz.....0..0i71j0j0i131j0i67j0i131i67j0i3j0i22i30.RdjN-mvSnek&amp;amp;ved=0ahUKEwjJloL11ZnkAhXfHrkGHZrCCFQQ4dUDCAo&amp;amp;uact=5&quot; rel=&quot;nofollow noreferrer&quot;&gt;Amazonas size&lt;/a&gt; Amazon size is 5.5 millions km². But according to this &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_countries_by_forest_area&quot; rel=&quot;nofollow noreferrer&quot;&gt;List of countries by forest area&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;World forest area is between 39 millions to 43 millions km2, depending if you believe the world forest area they give, or the added forest area of each country (which surpasses 43 millions km2) . I suppose other data is taking into account to say Amazonas create 20% of the oxygen.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is it said that Amazon creates 20% of the oxygen production of the world, when it accounts with less than 14-12.8% of the forest area?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastEditorUserId="9635" LastEditDate="2019-08-24T13:03:43.560" LastActivityDate="2019-08-30T04:40:19.690" Title="Why is it said that Amazon creates 20% of the oxygen production of the world, when it accounts with less than 14-12.8% of the forest area?" Tags="|forest|oxygen|amazon|" AnswerCount="3" CommentCount="15" ContentLicense="CC BY-SA 4.0" />
  <row Id="17823" PostTypeId="2" ParentId="17822" CreationDate="2019-08-23T23:16:38.213" Score="-1" Body="&lt;p&gt;The reason is: human nature. People like to exaggerate to make a point, and quite often they are such excellent liars that they believe their own exaggerations. Clearly the Amazon does not create 20 percent of the worlds oxygen. Most of the oxygen in the atmosphere is fossil oxygen, produced by photosynthetic organisms long before there were any rainforests, and as Universal Learner says, most of the CO2 disposal and oxygen production takes place in the oceans. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;By saying this, I don't mean to downplay the importance of the Amazon rainforest (some of it is rainforest and some is the more inflammable monsoon forest). It is full of desirable wild life, some of it rare and endangered. It is tragic to see so much of it disappearing. Nevertheless, naturalists, ecologists and environmentalists should try to be more objective and stick to the facts. Although the Amazon tropical forest doesn't provide as much oxygen or dispose of as much CO2 as is sometimes claimed, it still makes a valuable contribution.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-23T23:16:38.213" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17824" PostTypeId="2" ParentId="17822" CreationDate="2019-08-24T07:51:54.813" Score="8" Body="&lt;p&gt;I cannot find any language in peer-reviewed literature (as far as publicly accessible) that makes the 20% claim reported in the question. I therefore consider this claim to be of obscure and dubious origin.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;About 50% to 55% of the oxygen produced via photosynthesis is estimated to come from the world's oceans, as reported in the following two papers:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Curtis A. Suttle, &quot;Marine viruses -- Major players in the global ecosystem.&quot; &lt;em&gt;Nature Reviews Microbiology&lt;/em&gt; &lt;strong&gt;5&lt;/strong&gt; (10): 801-12 (2007)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The oceans cover more than 70% of the Earth’s surface. They control the climate, provide a significant amount of the protein that is consumed globally and produce approximately half of the Earth's oxygen.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A. Yu. Borisov, L. O. Björn, &quot;On oxygen production by photosynthesis: A viewpoint&quot;, &lt;em&gt;Photosynthetica&lt;/em&gt; (2018) 56: 44&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We also find that the ocean produces 22% more oxygen than the land surface.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;According to an expert quoted by the &lt;a href=&quot;https://www.bbc.com/news/world-latin-america-49450925&quot; rel=&quot;noreferrer&quot;&gt;BBC&lt;/a&gt;, about 16% of the &lt;em&gt;land-based&lt;/em&gt; oxygen production from photosynthesis occurs in the Amazon basin:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A large proportion of the world's oxygen is produced by plankton, explains Professor Malhi. He says of the oxygen produced by land-based plants, about 16% comes from the Amazon.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Is this claim plausible? Based on the reported size of Amazonian forests at 6-8 million km&lt;sup&gt;2&lt;/sup&gt; and the world's total forested area of about 40 million km&lt;sup&gt;2&lt;/sup&gt;, I am inclined to answer in the affirmative, although not all of the land-based oxygen production occurs in forested areas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://globalforestatlas.yale.edu/region/amazon&quot; rel=&quot;noreferrer&quot;&gt;Yale's Global Forest Atlas&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Amazon basin is the largest tropical rainforest in the world, covering a size approximately equal to the lower 48 United States. 6-8 million square kilometers of forest house approximately 10% of the world’s biodiversity and 15% of its freshwater.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.earth-policy.org/indicators/C56/forests_2012&quot; rel=&quot;noreferrer&quot;&gt;Based on data from the FAO suborganization of the UN&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Forests cover 31 percent of the world’s land surface, just over 4 billion hectares.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The area of a forest and its oxygen production are unlikely to be in strict linear proportion to one another, as the rate of photosynthesis should depend on such factors as solar irradiation (which varies with latitude and cloud cover) and temperature (in boreal forests) or the seasons (for deciduous forest in moderate climates). The density of a forest will likewise be influenced by the availability of water and nutrients.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How do scientists estimate the amount of oxygen produced via photosynthesis? Best I can tell from a perusal of the literature this is done indirectly by estimating total biomass, which itself is determined by a combination of satellite data and on-the ground measurements. Such estimates carry a non-trivial amount of uncertainty.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nowak, David J., Robert Hoehn, and Daniel E. Crane. &quot;Oxygen production by urban trees in the United States.&quot; &#xA;&lt;em&gt;Arboriculture &amp;amp; Urban Forestry.&lt;/em&gt; 33 (3): 220-226. (2007)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The net amount of oxygen produced by a tree during a year is directly related to the amount of carbon sequestered by the tree, which is tied to the accumulation of tree biomass.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;S.S. Saatchi, R.A. Houghton, R.C. Dos Santos Alvala, J.V. Soares and Y. Yu, &#xA;&quot;Distribution of aboveground live biomass in the Amazon basin&quot;,&#xA;&lt;em&gt;Global Change Biology&lt;/em&gt; (2007) 13, 816-837&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;To determine the spatial distribution of forest biomass of the Amazon basin, we report a method based on remote sensing metrics representing various forest structural parameters and environmental variables, and more than 500 plot measurements of forest biomass distributed over the basin. [...] We estimate that the total carbon in forest biomass of the Amazon basin, including the dead and belowground biomass, is 86 PgC with ± 20% uncertainty.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="5255" LastActivityDate="2019-08-24T07:51:54.813" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17825" PostTypeId="1" AcceptedAnswerId="17826" CreationDate="2019-08-24T18:06:48.103" Score="4" ViewCount="354" Body="&lt;p&gt;I want to know if a living rainforest in the Amazon, completely untouched by humans, is too wet for the fire to spread, even in the dryer months around July?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I.e. if somebody dropped 5000 gallons of gasoline there, put it on fire, would the fire spread, or would it die out after the gas has burned, because it is still too wet there?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or is it that the only areas that burn are those where the trees have been cut down (deforestation), the dead trees and remaining vegetation then have to dry out during the (relatively, for a rainforest) dryer months, and only then are they able to burn? Or does the fire spread into the actual living rainforest?&lt;/p&gt;&#xA;" OwnerUserId="17708" LastActivityDate="2019-08-24T19:49:15.527" Title="Is the rainforest too wet to burn?" Tags="|amazon|wildfire|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17826" PostTypeId="2" ParentId="17825" CreationDate="2019-08-24T19:49:15.527" Score="2" Body="&lt;p&gt;My personal experience of rainforest is confined to Malaysia, where it is too damp to burn unless it is first cut down and allowed to dry out in the sun. The fires on these ladangs, as they are called, never spread to nearby rainforest, and abandoned ladangs eventually become rainforest again.  I have some knowledge of other rainforests and have come to the conclusion that true rainforest is similar to Malaysia's. Throughout the wetter parts of the tropics, where there is not rainforest  there is a kind of forest called monsoon forest which is only wet for a few months of the year. After that it dries out and eventually loses it's leaves as though it were winter. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Often it is fairly close to real rainforest, so there is a gradual transition from monsoon forest to rain forest. Both kinds are found in Amazonia and Central America, Dropping 5,000 gallons of gasoline into a rainforest to see if it would burn would be regarded as very odd nowadays, but it frequently happened in WW2. Allied and Japanese aircraft were frequently shot down and crashed into the jungle, seldom with 5,000 gallons of fuel aboard but certainly enough to cause a fire. In Malaya and Borneo the jungle never caught fire, and although this happened all over S.E.Asia, surprisingly enough I have never heard of an incident where the jungle caught fire. There is some monsoon forest in India, but the fighting there was confined to Assam, where it is rainforest. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In modern times a large jet occasionally crashes into jungle, but again I have never heard of one setting he jungle alight. Jet fuel, of course, is not as inflammable as gasoline. Some of the fires in Brazil currently shown on TV look as though it is the sort of scrub which springs up on land which was once cultivated.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-24T19:49:15.527" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17827" PostTypeId="1" CreationDate="2019-08-24T21:18:27.863" Score="6" ViewCount="143" Body="&lt;p&gt;Most tropical cyclones rapidly weaken over land, however, given some conditions (such as very wet soil/ground cover and tropical lower atmospheric conditions) they can sustain themselves or even intensify over land, in a phenomenon known as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Brown_ocean_effect&quot; rel=&quot;noreferrer&quot;&gt;brown ocean effect&lt;/a&gt;. So, is it at all possible for extreme &quot;brown ocean&quot; conditions or other potential factors to result in not only the maintenance but the &lt;em&gt;formation&lt;/em&gt; of a tropical cyclone over land, either from an extratropical system or not? The intensity and duration of time that the storm would last without transitioning to water is irrelevant—even a few hours at tropical storm levels would be a yes.&lt;/p&gt;&#xA;" OwnerUserId="17317" LastActivityDate="2022-06-12T13:32:09.077" Title="Is there any possible way that a tropical cyclone of any strength could form over land?" Tags="|meteorology|geography|tropical-cyclone|cyclone|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17828" PostTypeId="2" ParentId="17822" CreationDate="2019-08-25T01:52:21.133" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Do we need to worry about oxygen?&lt;/strong&gt;&lt;br&gt;&#xA;  No. Although some reports have claimed the Amazon produces 20% of the world’s oxygen, it is not clear where this figure originated. The true figure is likely to be no more than 6%, according to climate scientists such as &lt;a href=&quot;https://twitter.com/MichaelEMann/status/1164899653525151745&quot; rel=&quot;nofollow noreferrer&quot;&gt;Michael Mann&lt;/a&gt; and &lt;a href=&quot;https://twitter.com/GlobalEcoGuy/status/1164732075301146624&quot; rel=&quot;nofollow noreferrer&quot;&gt;Jonathan Foley&lt;/a&gt; [Twitter links]. Even if it were accurate, the crops being planted in the cleared forest areas would also produce oxygen – quite likely at higher levels. So although the burning of the rainforest is worrying for many reasons, there is no need to worry about an oxygen shortage.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.theguardian.com/environment/2019/aug/23/amazon-fires-what-is-happening-anything-we-can-do&quot; rel=&quot;nofollow noreferrer&quot;&gt;Guardian&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Why is it said that Amazon creates 20% of the oxygen production of the world&lt;/strong&gt;&#xA;&lt;a href=&quot;http://www.yadvindermalhi.org/blog/does-the-amazon-provide-20-of-our-oxygen&quot; rel=&quot;nofollow noreferrer&quot;&gt;Yadvinder Malhi&lt;/a&gt; explains:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Below  I lay out the science of where this number comes from, and why it is incorrect when you have a whole-ecosystem view of the Amazon.&#xA;  The 20% figure comes from a partial understanding of the global oxygen cycle.&#xA;  The tropical forests account for about a 34% of global land surface photosynthesis. This is shown in the figure below (Beer et al. 2010, Science). The figure shows the global land distribution of photosynthesis - the rainforests are the big red patches and the Amazon accounts for about one half of the world's rainforests. Tropical rainforests photosynthesise so much because they have a year-long growing season not constrained by winter or drought.&lt;br&gt;&#xA;  &lt;a href=&quot;https://i.stack.imgur.com/wxwDu.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wxwDu.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;  ...&lt;br&gt;&#xA;  a bigger point that is often missed is that the Amazon consumes about as much oxygen as it produces. This is shown in the diagram below. Plants produce oxygen through photosynthesis (green arrow). However, the the same plants consume the equivalent of over half the oxygen they produce in their own respiration (blue arrows: my own team's research suggests this is more like 60%). Plants metabolise just as animals do, just at a slower rate, and at night when there is no photosynthesis forests are net absorbers of oxygen. The remaining 40% of the Amazon oxygen budget is consumed mainly by microbes breaking down the dead leaves and wood of the rainforest, a natural process called heterotrophic respiration (dark blue arrows).&#xA;  These process of plant and heterotrophic respiration are effectively the reverse of the photosynthesis equation above.&lt;br&gt;&#xA;  &lt;a href=&quot;https://i.stack.imgur.com/3TcYs.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3TcYs.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2019-08-30T04:40:19.690" LastActivityDate="2019-08-30T04:40:19.690" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17830" PostTypeId="2" ParentId="17827" CreationDate="2019-08-25T07:05:50.287" Score="2" Body="&lt;p&gt;No, it isn't possible for cyclones, hurricanes and typhoons, which are all different names for the same thing, to form over land. Storms can form over land, but not hurricanes, which draw their power from the sun-warmed ocean and rapidly lose their strength when they hit land. The power of a typical hurricane is immense, probably in excess of 50 megatons, which was the yield of the largest hydrogen bomb ever tested (by Russia).&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-25T07:05:50.287" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17831" PostTypeId="2" ParentId="10575" CreationDate="2019-08-25T12:53:40.350" Score="0" Body="&lt;p&gt;The answer is Nitrogen. Pay attention that nitrogen must be mineralized before it is available for plants:&#xA;&lt;a href=&quot;https://cropaia.com/blog/nitrogen-in-plants/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://cropaia.com/blog/nitrogen-in-plants/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17713" LastActivityDate="2019-08-25T12:53:40.350" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17832" PostTypeId="1" CreationDate="2019-08-25T17:06:21.837" Score="4" ViewCount="123" Body="&lt;p&gt;I am following climate activist Greta Thunberg's sail to N America from Europe on &lt;a href=&quot;https://tracker.borisherrmannracing.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://tracker.borisherrmannracing.com/&lt;/a&gt;. The model shows a cyclonic storm forming south of Nova Scotia, east of New York on August 26, 2019. The same thing can be seen on &lt;a href=&quot;https://earth.nullschool.net/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earth.nullschool.net/&lt;/a&gt;. I wasn't aware that this type of storm formed so far north and am wondering why this storm is forming and if this is a rare occurrence that may be related to climate change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ya8x1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ya8x1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit to add: Here is the model of air temperature. It appears to me that the storm forms at the interface between cool air from the north and warm air from the south and that the core is warm, but perhaps someone with more expertise can weigh in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ixN6U.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ixN6U.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1242" LastEditorUserId="1242" LastEditDate="2019-08-25T23:18:11.573" LastActivityDate="2019-08-26T12:02:06.633" Title="Is it normal for a cyclonic storm to form at the latitude of New York, USA?" Tags="|meteorology|climate-change|tropical-cyclone|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17833" PostTypeId="2" ParentId="17805" CreationDate="2019-08-25T17:19:12.837" Score="0" Body="&lt;p&gt;The cyllindrical Mercator projection, or the &lt;a href=&quot;https://en.wikipedia.org/wiki/Web_Mercator_projection&quot; rel=&quot;nofollow noreferrer&quot;&gt;Web Mercator Projection&lt;/a&gt;, as used by Google Maps (which uses projection &lt;a href=&quot;https://epsg.io/3857&quot; rel=&quot;nofollow noreferrer&quot;&gt;EPSG:3857&lt;/a&gt;), &lt;a href=&quot;https://www.openstreetmap.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;OpenStreetMaps&lt;/a&gt; and may other projects - all these preserve latitude. So if you will browse most of the online maps, you will see the latitude preserved :-)&lt;/p&gt;&#xA;" OwnerUserId="165" LastActivityDate="2019-08-25T17:19:12.837" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17834" PostTypeId="2" ParentId="17832" CreationDate="2019-08-25T18:00:13.757" Score="-2" Body="&lt;p&gt;No, it's not normal. Hurricanes and typhoons require sun-warmed seas like the Caribbean or Gulf of Mexico to form, because that's where they get their energy from. When meteorologists talk of cyclones and anticyclones, they are talking about high pressure or low pressure weather systems, not hurricanes and typhoons. Storms can form that far north, but probably not hurricanes, typhoons or cyclones, which are just different names for the same thing. When referring to the mega-storms which devastate tropical and subtropical islands, the terms hurricane (Atlantic) or typhoon (Pacific) are usually used. I don't think the weather system featured in your diagram was a hurricane.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-25T18:00:13.757" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17836" PostTypeId="1" AcceptedAnswerId="17845" CreationDate="2019-08-25T20:36:19.820" Score="2" ViewCount="124" Body="&lt;p&gt;Comparing the picture from Wikipedia that delimits the Amazon rainforest and the picture of the recent dramatic fires in the area that NASA published, what I can gather is that the burned zone is the periphery of the forest and not the forest itself.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kmA6t.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kmA6t.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;Source: &lt;a href=&quot;https://es.wikipedia.org/wiki/Amazonia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Max1c.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Max1c.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;Recent fires on South America, NASA&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;As much of South America is on fire, I wonder if the absence of fires in the Amazon is related to its resistance to fires due to its being too wet, as suggested in &lt;a href=&quot;https://earthscience.stackexchange.com/q/17825&quot;&gt;this question&lt;/a&gt;, or due to other reasons as absence of human activity on the truly wild parts of the Amazon.&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorUserId="6129" LastEditorDisplayName="user12525" LastEditDate="2020-09-13T04:39:23.727" LastActivityDate="2020-09-13T04:39:23.727" Title="Is the Amazon rainforest resistant to fires?" Tags="|forest|wildfire|amazon|rainforest|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17837" PostTypeId="2" ParentId="17836" CreationDate="2019-08-25T22:00:46.293" Score="0" Body="&lt;p&gt;I only have personal experience of the rainforest in Malaysia (Sarawak, Sabah and Peninsular Malaya), but that experience was very extensive and included a total of about two years actually living in the jungle and patrolling it. I also had good opportunities to see it from the air. This was genuine rainforest, and only inflammable if it was cut down and dried in the sun, which now and again in small patches, it was. I have no personal experience of Amazonia, but I know that some of it is monsoon forest, which is only wet for a few months of the year. Nevertheless, some of it must be genuine primary rainforest, in which case it will be the same as Malaysian rainforest. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suspect that some of the fires shown in your diagram are in dry areas which are not proper rainforest, and others are where the forest has been felled and dried out, then set on fire. A lot of them are not even in Brazil. The blank area is probably the real rainforest, which doesn't burn and where there is little human activity. Movement on foot is very difficult in rainforest, and also dangerous, so few people other than the natives who live there wander about in it. So the answer to your question is yes,where it is true primary rainforest,it is resistant to fire.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-25T22:00:46.293" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17839" PostTypeId="1" AcceptedAnswerId="17854" CreationDate="2019-08-26T10:42:28.273" Score="5" ViewCount="2056" Body="&lt;p&gt;Please, let me know if this question is too technical/specific for Earth Science. In case, I will remove it and eventually post it elsewhere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am processing some data extracted from ERA5 to set up a large scale hydrological model. We are calculating the evapotranspiration using the typical &lt;a href=&quot;http://www.fao.org/3/X0490E/x0490e08.htm#calculation%20procedure&quot; rel=&quot;nofollow noreferrer&quot;&gt;P-M formula&lt;/a&gt;, using as input the usual variables: wind speed, solar radiation, temperature, pressure, relative humidity and so on. In order to check the consistency of our calculations with the  variables provided by the ECMWF, I downloaded also some evaporation related variables. I'm struggling to understand the data related to the &lt;code&gt;mean evaporation rate&lt;/code&gt; variable data. ERA5 are available at hourly time steps at ~0.28 degrees spatial resolution. For the &lt;code&gt;mean evaporation rate&lt;/code&gt;, Minimum, Mean, and Maximum values are provided expressed in &lt;code&gt;kg x sqmt x sec-1&lt;/code&gt;. Data look like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bF8vW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bF8vW.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;code&gt;ncdump&lt;/code&gt; is the following:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VG0uZ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VG0uZ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and plotting the mean values for a hour during the day, would look like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OSAsB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OSAsB.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What looks not clear to me is why the mean evaporation rate is negative: I would expect a positive value in the wet regions and zero over the deserts. I tried to look at the &lt;a href=&quot;https://confluence.ecmwf.int/display/CKB/ERA5+data+documentation&quot; rel=&quot;nofollow noreferrer&quot;&gt;ERA5 data documentation&lt;/a&gt;, but the issue is not addressed there. Am I misinterpreting something? &lt;/p&gt;&#xA;" OwnerUserId="8087" LastEditorUserId="8087" LastEditDate="2019-08-26T12:12:37.960" LastActivityDate="2019-08-28T12:00:35.583" Title="ERA5 mean evaporation rates data - Why is that negative?" Tags="|evaporation|era|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="17840" PostTypeId="2" ParentId="17832" CreationDate="2019-08-26T12:02:06.633" Score="4" Body="&lt;p&gt;A cyclone is nothing more than a low-pressure system. It can surely form in the North Atlantic; in fact, most low-pressure systems that reach Europe form in the North Atlantic.&#xA;You are probably thinking about a &lt;em&gt;tropical&lt;/em&gt; cyclone, which indeed cannot form that far north. Among others, a tropical cyclone needs high sea temperatures (&gt;27 C), which are usually not present at such high latitudes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;About the present cyclone south of Nova Scotia: I think it is a cold core cyclone, as 500 hPa temperature are lower than in surroundings (which is e.g. not the case for tropical storm Dorian, which is currently east from the Lesser Antilles). Therefore, it's not a tropical cyclone but an ordinary extra-tropical cyclone, which can perfectly form at those latitudes.&lt;/p&gt;&#xA;" OwnerUserId="17719" LastActivityDate="2019-08-26T12:02:06.633" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17841" PostTypeId="1" CreationDate="2019-08-26T18:27:20.683" Score="1" ViewCount="34" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/X8tDU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/X8tDU.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to know how I can put all this data into one graph. I thought that temperature can be graphed as a bar graph and precipitation could be used with a line graph. However I don't know how i can include all four cities. &lt;/p&gt;&#xA;" OwnerUserId="17721" LastActivityDate="2019-08-26T18:27:20.683" Title="How can I describe this data using a graph?" Tags="|temperature|precipitation|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17842" PostTypeId="2" ParentId="17809" CreationDate="2019-08-26T18:42:17.580" Score="3" Body="&lt;p&gt;Civil twilight: the sun is between 0 and 6 degrees below the horizon&lt;br /&gt;&#xA;Nautical twilight: the sun is between 6 and 12 degrees below the horizon&lt;br /&gt;&#xA;Astronomical twilight: the sun is between 12 and 18 degrees below the horizon&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I believe if the sun is lower than 18 degrees below the horizon, all sun rays can no longer reach your location. Hence it is completely dark.&lt;/p&gt;&#xA;" OwnerUserId="17719" LastActivityDate="2019-08-26T18:42:17.580" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17843" PostTypeId="1" CreationDate="2019-08-27T02:52:13.010" Score="2" ViewCount="954" Body="&lt;p&gt;I understand how and why low pressure systems are often associated with rain, but does the rain itself (both during and after) alter barometric pressure in any meaningful way?&lt;/p&gt;&#xA;" OwnerUserId="17723" LastActivityDate="2019-08-29T17:45:14.460" Title="Does rain itself affect barometric pressure?" Tags="|meteorology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17844" PostTypeId="2" ParentId="17843" CreationDate="2019-08-27T06:20:06.330" Score="0" Body="&lt;p&gt;No. Low pressure affects the rain, not the other way around. Air at high pressure/density can hold more moisture than air at low pressure, so when there is a reduction in pressure the moisture content, or some of it, condenses and is precipitated. Reduction of temperature can also cause precipitation, because cold air holds less moisture than warm air. Reduction of temperature can be brought about by lowering of pressure.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-08-27T06:59:43.283" LastActivityDate="2019-08-27T06:59:43.283" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="17845" PostTypeId="2" ParentId="17836" CreationDate="2019-08-27T12:43:51.563" Score="4" Body="&lt;p&gt;Most fires are probably in the periphery because they are &lt;a href=&quot;https://www.businessinsider.nl/fires-in-the-amazon-rainforest-were-started-by-humans-2019-8?international=true&amp;amp;r=US&quot; rel=&quot;nofollow noreferrer&quot;&gt;started by humans&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;They encroach on the jungle from the outside, where they already live, and there are roads instead of impenetrable jungle.&lt;/p&gt;&#xA;" OwnerUserId="595" LastActivityDate="2019-08-27T12:43:51.563" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17846" PostTypeId="1" AcceptedAnswerId="17847" CreationDate="2019-08-27T20:56:03.847" Score="1" ViewCount="101" Body="&lt;p&gt;I have a theoretical question. I have been reading on what would happen if the earth suddenly stopped rotating around its axis, and I have learned that would result in the annihilation of all life on the planet. I also learned that the earth rotates currently at 465 meters/second.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, my question. What is the optimal deceleration factor that would allow the earth to stop over time (and not suddenly), while allowing live to continue? How do I build a machine to slow down the earth to a complete stop, without destroying all life on planet?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks.&lt;/p&gt;&#xA;" OwnerUserId="17729" LastEditorUserId="20" LastEditDate="2019-08-30T01:17:49.170" LastActivityDate="2019-08-30T01:17:49.170" Title="Stop earth rotation around its axis" Tags="|earth-rotation|hypothetical|" AnswerCount="1" CommentCount="3" ClosedDate="2019-08-28T11:37:51.853" ContentLicense="CC BY-SA 4.0" />
  <row Id="17847" PostTypeId="2" ParentId="17846" CreationDate="2019-08-27T22:27:57.857" Score="1" Body="&lt;p&gt;Slowing the planet would have major consequences. Stopping the planet would have major consequences (here are some: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2236/effect-on-sea-level-if-the-earth-stopped-rotating&quot;&gt;Effect on sea level if the Earth stopped rotating&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Doing either of these things too quickly would have even greater consequences, but trying to predict these consequences and the effects for life on earth would be (a) a major primary research project, and (b) perhaps impossible. The answer is that we just don't know, and I doubt that anybody is about to fund the research ;-)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;How&lt;/em&gt; to do it is, as I suspect you realise, also a very big question. I mean, if for some reason you wanted to. The difficulty is conservation of angular momentum: for the planet to have stopped turning, you need to have shifted that angular momentum somewhere else. That &lt;em&gt;probably&lt;/em&gt; means firing stuff into space, or using tidal mechanisms (as somebody noted re the Moon), or maybe building a giant / massive flywheel on the Earth's axis and spinning it really fast the other way..... all of these are, of course, well into the realm of science fiction.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-08-27T22:27:57.857" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17849" PostTypeId="1" CreationDate="2019-08-28T06:19:58.633" Score="1" ViewCount="165" Body="&lt;p&gt;Volcanoes spit out magma onto the surface of the crust or crevices on the surface, but the magma comes (in effect) from the mantle right? If that's the case, isn't the mantle turning into the crust by the mantle hardening into mountains and volcanoes? Or maybe the mantle doesn't change size, it just melts more of the crust to suit its size needs. If that was the case, the areas of Earth that aren't constantly spitting magma onto the surface would eventually be thinned out to the point that a hole or giant crack would appear leading straight to the mantle and that would be bad.&lt;/p&gt;&#xA;" OwnerUserId="17733" LastActivityDate="2019-09-27T09:01:15.420" Title="Q: Is the crust getting thinner or is the mantle getting smaller" Tags="|volcanology|tectonics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17850" PostTypeId="1" CreationDate="2019-08-28T07:54:24.413" Score="0" ViewCount="12641" Body="&lt;p&gt;Is it possible That The process that had occurred with the flood have actually petrified ginormous tree stumps during the flood??&lt;/p&gt;&#xA;" OwnerUserId="17734" LastActivityDate="2019-08-28T20:23:24.123" Title="Can Some not all mountains actually be Giant petrified Tree Stumps?" Tags="|soil-science|" AnswerCount="2" CommentCount="3" ClosedDate="2019-08-28T16:04:25.520" ContentLicense="CC BY-SA 4.0" />
  <row Id="17851" PostTypeId="2" ParentId="17849" CreationDate="2019-08-28T08:18:37.813" Score="1" Body="&lt;p&gt;The crust is actually getting thicker very gradually as the Earth cools down. This process is well seen on Mars, where due to its smaller size and greater distance from the sun, Mars is cooling faster than the Earth. No one knows exactly how thick the Martian crust is, but what we do know is that magma can no longer find its way to the surface. All the Martian volcanoes are extinct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On Earth, the magma ejected from volcanoes is mostly recycled oceanic crust. Sea floor spreading from the mid-ocean ridge pushes the oceanic crust on the Pacific Plate toward the continental crust on,for example, the North American plate, where it is forced to dive  beneath the continental crust and driven down into the mantle. For a number of reasons (friction, water content etc) this causes it to melt, and being lighter and more fluid than the mantle it rises to the surface, where it escapes through volcanism.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is not the whole story, because if oceanic crust is disappearing as it is pushed below the continental crust of another plate, it must somehow be replaced. This happens at the mid ocean ridge, where a deep chasm plunges through the comparatively thin oceanic crust, enabling fresh magma from the mantle to rise up and create new ocean floor. This is constantly spreading out in opposite directions from the mid ocean ridge, hence the term 'sea floor spreading'.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-28T08:18:37.813" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17852" PostTypeId="2" ParentId="17850" CreationDate="2019-08-28T08:51:52.887" Score="0" Body="&lt;p&gt;I think I know what you are talking about. There are geological formations called volcanic plugs, which bear a strong resemblance to gigantic tree stumps and might easily fool people who knew nothing about geology into thinking that's what they were. Many millions of years ago the magma inside a volcanic cone cooled and solidified, and the volcano became extinct. During the course of millions of years of weathering, the softer, outer parts of the volcano were eroded away, leaving just the harder core still standing. Edinburgh Castle is sited on top of one of these volcanic plugs, but the presence of the castle disguises its tree-stump-like appearance. This particular volcanic plug is about 350 million years old.  I don't think there are any which are three kilometres high, this one certainly isn't. Devil's Tower in Wyoming USA is a good example of the kind of plug I mean, but I have seen better ones (see Wickepedia). Anyone with a knowledge of botany would know that a tree of such dimensions would be a physical impossibility.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-08-28T20:23:24.123" LastActivityDate="2019-08-28T20:23:24.123" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17853" PostTypeId="2" ParentId="17850" CreationDate="2019-08-28T10:27:24.387" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;...the process that had occurred with the flood...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm assuming that you are talking about the biblical flood. There is no evidence that the flood had ever occurred.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Can...mountains actually be Giant petrified Tree Stumps?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No. Petrified trees are made of silica with a very distinct texture as &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Polished_petrified_wood_cells.jpg#/media/File:Polished_petrified_wood_cells.jpg&quot; rel=&quot;noreferrer&quot;&gt;observed in the microscope&lt;/a&gt;. All mountains are made of other things. For example, granite, limestone, basalt, and various types of rock. Some mountains are made of sandstone quartzite, which are compositionally similar to what petrified wood is made off. However, sandstone is just hardened sand, and quartzite is sandstone that has become even more hardened due to the high temperatures and pressures deep in the Earth. They looking nothing like petrified wood.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-08-28T10:27:24.387" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17854" PostTypeId="2" ParentId="17839" CreationDate="2019-08-28T12:00:35.583" Score="7" Body="&lt;p&gt;Just leaving this for future readers. I finally found in some ECMWF &lt;a href=&quot;https://apps.ecmwf.int/codes/grib/param-db?id=182&quot; rel=&quot;noreferrer&quot;&gt;documentation&lt;/a&gt; (referring to a different variable) that: &quot;&lt;em&gt;The ECMWF Integrated Forecasting System convention is that downward fluxes are positive. Therefore, negative values indicate evaporation and positive values indicate condensation&lt;/em&gt;&quot;. This applies also to other variables.&#xA;Thanks to Daniel and Spencer for their help.&lt;/p&gt;&#xA;" OwnerUserId="8087" LastActivityDate="2019-08-28T12:00:35.583" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17855" PostTypeId="1" CreationDate="2019-08-28T12:12:39.653" Score="1" ViewCount="54" Body="&lt;p&gt;I've found this data, which I'm not sure it's right. This article claims the area burnt in Amazon this year is 1,330 square miles (344,468 hectareas) &lt;a href=&quot;https://www.washingtonpost.com/climate-environment/what-you-need-to-know-about-the-amazon-rainforest-fires/2019/08/27/ac82b21e-c815-11e9-a4f3-c081a126de70_story.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Amazon rainforest fires&lt;/a&gt; . And this other article claims the 2018 California wildfires burnt 766,439 hectareas &lt;a href=&quot;https://en.wikipedia.org/wiki/2018_California_wildfires&quot; rel=&quot;nofollow noreferrer&quot;&gt;2018 California wildfires&lt;/a&gt; . Is this so? Is the area burnt in Amazon rainforest less than half than the area burnt in 2018 California wildfires?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastActivityDate="2019-08-28T14:44:01.513" Title="Is the area burnt in Amazonas quite smaller than the 2018 California wildfires?" Tags="|amazon|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17856" PostTypeId="1" CreationDate="2019-08-28T13:15:28.487" Score="1" ViewCount="96" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ABsiD.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ABsiD.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why hasn't the subduced Farallon Plate's materials been recycled? Why do they appear to be flowing in a molten state?&lt;/p&gt;&#xA;" OwnerUserId="17736" LastActivityDate="2019-08-28T13:39:11.647" Title="How have Farallon plates's remnants stayed as they were inside the mantle?" Tags="|plate-tectonics|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17857" PostTypeId="2" ParentId="17856" CreationDate="2019-08-28T13:39:11.647" Score="1" Body="&lt;p&gt;Rock is dense, is a good insulator, and usually has very high specific heat capacity; the crust is also kilometers thick. The combination of these qualities means that it takes a very long time, even geologically speaking, for crustal blocks to melt completely in the mantle. This is exacerbated by the fact that the mantle, especially the shallow layers close to the crust, is not actually much hotter than the melting point of most of the minerals in the rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason that the crust is still visible in seismic wave variances while it moves in an apparently molten fashion is that even though it hasn't been completely melted it has been in the mantle long enough to reach a uniform high temperature, high enough to become plastic and flexible. So it still presents as a density anomaly because its not yet as molten as the material around it but it will flow, if slowly, because it is semi-molten, similar to the asthenosphere.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2019-08-28T13:39:11.647" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17859" PostTypeId="2" ParentId="17855" CreationDate="2019-08-28T14:44:01.513" Score="-1" Body="&lt;p&gt;It is very likely true. Most of the fires shown on TV and in maps are not in Amazonia and not in true rainforest. Quite a lot of them are not even in Brazil. The amount of Amazonian rainforest burning is therefore relatively small, and is due to land clearance and illegal logging where the trees have been cut down and what is left allowed to dry out in the sun and then burned. Out-of-control wildfires are possible in California, but not in true rainforest, which is too damp.  A few very small fires may be due to forest-dwelling natives clearing a small patch and setting fire to it for slash and burn, short-term cultivation. They will abandon it in about 5 years time when the soil is exhausted and the rainforest will gradually take over again.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-28T14:44:01.513" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17861" PostTypeId="1" CreationDate="2019-08-28T17:21:35.223" Score="3" ViewCount="888" Body="&lt;p&gt;I have download ERA5 netCDF file in order to get precipitation monthly/daily rates for 11 years. But I have realized, there is no option to select my area of interest. It seems it is a big file to handle.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I am currently using R language and but still in the basic level. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is about if there is anyway to extract precipitation values for a certain area? &lt;/p&gt;&#xA;" OwnerUserId="17740" LastEditorUserId="6031" LastEditDate="2019-08-28T20:57:59.430" LastActivityDate="2019-08-29T10:30:18.473" Title="downloading ERA5 netCDF daily data for a decade, how to restrict location to reduce data size?" Tags="|climate|era|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17862" PostTypeId="1" CreationDate="2019-08-28T23:39:17.957" Score="3" ViewCount="55" Body="&lt;p&gt;I am working in a catchment in the southern Ecuadorian Andes, about 3700 m.a.sl. Rock outcrops at the upper part of the catchment, as massive blocks varying their size from one meter up to five meters, as shown in the first picture. Based on my limited knowledge of geology I would say that the rocks are of volcanic nature, probably andesite/rhyolite, very massive, dark in color with visible white crystals (Picture 2). I noticed that a lot of the rocks,  present scars/marks on their surface (Picture 3) and I would like to now their possible origins.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These areas are suspected that were covered by glaciers during the last glaciation. The catchment is located close to the rim of an old caldera. &lt;a href=&quot;https://i.stack.imgur.com/f83oS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/f83oS.jpg&quot; alt=&quot;Picture 1: Overall view of the catchment with outcrops visible.&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WKfhn.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WKfhn.jpg&quot; alt=&quot;Outcrop rock detail&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2H9s7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2H9s7.jpg&quot; alt=&quot;Marks&amp;#39; details.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5820" LastEditorDisplayName="user12525" LastEditDate="2019-08-29T09:15:12.717" LastActivityDate="2019-08-29T11:09:37.713" Title="Marks on boulders of volcanic origin" Tags="|geology|rocks|petrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17863" PostTypeId="1" AcceptedAnswerId="19055" CreationDate="2019-08-29T02:32:09.260" Score="4" ViewCount="277" Body="&lt;p&gt;So it is my understanding the Washington's Olympic Mountains are basaltic mountains. The reason is that they formed from the upthrust of Ocean crust rather than continental crust as the Farallon plate was pushed under the North American plate. Are there any other mountain ranges (worldwide), particularly coastal ranges made of basalt oceanic crust, that have roughly the same geology?&lt;/p&gt;&#xA;" OwnerUserId="17742" LastEditorUserId="595" LastEditDate="2019-08-30T07:15:52.537" LastActivityDate="2020-01-27T12:07:11.530" Title="Are the Olympic Mountains (in Washington state) geologically unique?" Tags="|mountains|subduction|orogeny|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17864" PostTypeId="1" CreationDate="2019-08-29T09:04:04.363" Score="1" ViewCount="145" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/m05Zf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/m05Zf.png&quot; alt=&quot;a part of offset corner&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried to understand about Offset Corner Latitude Point 1,2,3,4 and Offset Corner Longitude Point 1,2,3,4. But I couldn't understand what is it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, I have the Frame center Latitude and Longitude. Can I calculate latitude and longitude of Frame Corners?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does someone can explain me about Offset Corner Latitude and Longtitude?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;sources: &lt;a href=&quot;https://gwg.nga.mil/misb/docs/eg/EG0601.1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://gwg.nga.mil/misb/docs/eg/EG0601.1.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/1/19/MISB_Standard_0601.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://upload.wikimedia.org/wikipedia/commons/1/19/MISB_Standard_0601.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17744" LastEditorUserId="17744" LastEditDate="2019-08-29T11:31:02.730" LastActivityDate="2019-08-29T11:31:02.730" Title="What is the Offset Corner Latitude and Longtitude?" Tags="|geography|mapping|satellites|coordinate-system|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17865" PostTypeId="2" ParentId="17861" CreationDate="2019-08-29T09:04:09.373" Score="2" Body="&lt;p&gt;There are two ways to get this done:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1- you can select the specific domain of interest when downloading the files. This is highly preferred when you have to download a large number of variables and years. ERA5 netCDF are offered in two different formats: either at hourly time steps, or at monthly averages (see &lt;a href=&quot;https://cds.climate.copernicus.eu/cdsapp#!/search?type=dataset&amp;amp;text=era5&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;). If you need a sub-monthly time steps the global files for many variables for long time periods are extremely heavy in terms of disk space. You could set up a python script to download the data selecting only the domain by following a procedure like the one suggested in this &lt;a href=&quot;https://retostauffer.org/code/Download-ERA5/&quot; rel=&quot;nofollow noreferrer&quot;&gt;nice post by Reto Stauffer&lt;/a&gt; (of course there are other ways to do this). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;2- you can download the global netCDF of the variable and year under consideration ad use a software to extract your domain of interest.&#xA;One of the most efficient systems to do that is using the Climate Data Operator CDO. you could use the &lt;code&gt;sellonlatbox&lt;/code&gt; with a command like&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cdo sellonlatbox,LON1,LON2,LAT1,LAT2 Input_file_Name.nc Output_file_Name.nc&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Or you could use &lt;code&gt;R&lt;/code&gt;, as for your case, doing something like: &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;library(raster)&#xA;library(rgdal)&#xA;&#xA;#load your area of interest&#xA;setwd(&quot;path_domain_shapefile&quot;)&#xA;domain_shp&amp;lt;-readOGR(&quot;shapefile.shp&quot;)&#xA;&#xA;#read netCDF&#xA;setwd(&quot;path_to_ERA5_files_folder&quot;)&#xA;pr_data&amp;lt;-stack(&quot;ERA5_file.nc&quot;)&#xA;&#xA;#extract the data for your area of interest&#xA;pr_data_domain&amp;lt;-extract(pr_data, domain_shp)&#xA;&#xA;#then you can transform this in a data frame and write it as a csv&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;As reference for basic operations with spatial data in &lt;code&gt;R&lt;/code&gt;, I would suggest this &lt;a href=&quot;http://www.spatialecology.com/beyer/assets/Beyer_Introduction_to_geospatial_analysis_in_R.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;introduction guide&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this helps.&lt;/p&gt;&#xA;" OwnerUserId="8087" LastEditorUserId="8087" LastEditDate="2019-08-29T10:30:18.473" LastActivityDate="2019-08-29T10:30:18.473" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17866" PostTypeId="1" CreationDate="2019-08-29T09:09:31.460" Score="2" ViewCount="1807" Body="&lt;p&gt;According to Elon Musk, there's &quot;an argument&quot; stating that the current level of carbon in the atmosphere (more than 400 ppm) is better than it was some hundreds of years ago (200 ppm). He even calls these low carbon levels carbon starvation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=kzlUyrccbos&amp;amp;t=45m4s&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=kzlUyrccbos&amp;amp;t=45m4s&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is this argument based on? What harm would it do if the level fell again to 200 ppm?&lt;/p&gt;&#xA;" OwnerUserId="11295" LastActivityDate="2022-06-05T14:35:17.927" Title="Why is more carbon in the atmosphere good, up to a certain level?" Tags="|atmosphere|climate|carbon|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17867" PostTypeId="2" ParentId="17866" CreationDate="2019-08-29T10:51:56.623" Score="-1" Body="&lt;p&gt;Musk didn't state his reasoning, but the only benefits of higher CO2 levels that I can see are that a) plants grow more vigorously, so therefore we can expect better crops, and where damaged forest is left alone it will regenerate more quickly, b) climate warming is an insurance against the next ice age or little ice age. There was a Little Ice Age between about 1350 and AD 1810 (estimated dates vary, as there were no accurate climate records in the Middle Ages). LIAs are believed to be associated with periods of low sunspot activity called Maunder Minimums, and some scientists say we are now on the verge of another.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Milankovitch Cycles only tell you when a proper ice age is likely, they are rather complex and don't accurately predict Ice Ages. We can be sure that there will be another ice age, but no one knows exactly when.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The down sides of higher CO2 levels are so well known that it shouldn't be necessary for me to enumerate them. The question was: are there any advantages to higher carbon levels, so I have answered it.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-29T10:51:56.623" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17868" PostTypeId="2" ParentId="17862" CreationDate="2019-08-29T11:09:37.713" Score="1" Body="&lt;p&gt;The rocks are undoubtedly of volcanic origin, and I would attribute the marks on their surfaces to shrinkage while their interiors were still in a semi-molten condition but rapidly cooling. The white crystals are probably quartz.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-29T11:09:37.713" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17870" PostTypeId="2" ParentId="17843" CreationDate="2019-08-29T17:45:14.460" Score="1" Body="&lt;p&gt;Under a hydrostatic assumption the basic equation is &lt;code&gt;p=/rho R T&lt;/code&gt;. So under this easy equation the pressure depends to the air density and the air temperature. As you may know diabatic processes during rain yield to a decreasing temperature. but the magnitude in change of pressure against the synoptic scale forcing is low. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please be aware of mixing stuff together answering this questions. The question was not to answer how precipitation is forming. It was just the question about the rain influencing the pressure. &lt;/p&gt;&#xA;" OwnerUserId="17681" LastActivityDate="2019-08-29T17:45:14.460" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17874" PostTypeId="1" CreationDate="2019-08-29T23:02:59.123" Score="1" ViewCount="32" Body="&lt;p&gt;Will rare earth sulfides in soil be more soluble in aqueous solutions with lower pH? How can I know whether these sulfides will dissolve better at low or high pH or will it not be affected?&lt;/p&gt;&#xA;" OwnerUserId="17750" LastActivityDate="2019-08-29T23:02:59.123" Title="solubility of rare earth sulphides at different pH?" Tags="|geochemistry|soil|rare-earth|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17875" PostTypeId="2" ParentId="17866" CreationDate="2019-08-29T23:19:54.950" Score="7" Body="&lt;p&gt;If plants were growing poorly when atmospheric CO2 was 200ppm, it was probably because Earth was in the middle of an ice age and covered with glaciers, not because plants were starved of carbon dioxide.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All things being equal, increasing the amount of carbon dioxide available in the atmosphere can benefit some plants, but the problem is that all things do not remain equal.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;CO2 is only a fertilizer in environments where CO2 is the limiting input for a plant; plants in the outdoors may receive too little moisture, too much warmth, or too little sun for additional CO2 to make much difference.&lt;/li&gt;&#xA;&lt;li&gt;Adding CO2 to the atmosphere also changes global and regional climates, reducing precipitation and increasing temperatures in ways that offset benefits from CO2 fertilization.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The authors of &lt;a href=&quot;https://www.nature.com/articles/ngeo2284&quot; rel=&quot;noreferrer&quot;&gt;Plant growth enhancement by elevated CO2 eliminated by joint water and nitrogen limitation&lt;/a&gt; in &lt;a href=&quot;https://www.nature.com/ngeo&quot; rel=&quot;noreferrer&quot;&gt;Nature Geoscience&lt;/a&gt; found that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the presence of a CO2 fertilization effect depends on the amount of&#xA;  available nitrogen and water. Specifically, elevated CO2 levels led to&#xA;  an increase in plant biomass of more than 33% when summer rainfall,&#xA;  nitrogen supply, or both were at the higher levels (ambient for&#xA;  rainfall and elevated for soil nitrogen). But elevated CO2&#xA;  concentrations did not increase plant biomass when both rainfall and&#xA;  nitrogen were at their lower level. We conclude that given widespread,&#xA;  simultaneous limitation by water and nutrients, large stimulation of&#xA;  biomass by rising atmospheric CO2 concentrations may not be&#xA;  ubiquitous.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Scientific American tackled the question in &lt;a href=&quot;https://www.scientificamerican.com/article/ask-the-experts-does-rising-co2-benefit-plants1/&quot; rel=&quot;noreferrer&quot;&gt;Ask the Experts: Does Rising CO2 Benefit Plants?&lt;/a&gt;, concluding that &quot;Climate change’s negative effects on plants will likely outweigh any gains from elevated atmospheric carbon dioxide levels.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Researchers cited in that article pointed out that added CO2 provides diminishing returns, with Samuel Myers, principal research scientist in environmental health at Harvard University, noting that “We know unequivocally that when you grow food at elevated CO2 levels in fields, it becomes less nutritious.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second part of your question was what would happen if CO2 levels fell to 200 ppm. This is unlikely to happen on human timescales; the current CO2 level is about 410ppm, rising 3-5 ppm per year. CO2 levels were at about 280ppm for most of human civilization, only increasing substantially when fossil fuel use became widespread in the 1800s. CO2 has a residence time in the atmosphere of several centuries.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2019-08-29T23:19:54.950" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17876" PostTypeId="1" AcceptedAnswerId="17877" CreationDate="2019-08-30T06:04:32.607" Score="3" ViewCount="462" Body="&lt;p&gt;I am asking myself something very interesting for me (I am not expert in this topic).&lt;/p&gt;&#xA;&lt;p&gt;I read many websites about human history and every website says that there are some periods in the human history.&lt;/p&gt;&#xA;&lt;p&gt;For example: &lt;a href=&quot;https://www.inrap.fr/en/periods&quot; rel=&quot;nofollow noreferrer&quot;&gt;periods&lt;/a&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Paleolithic&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Mesolithic&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Neolithic&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Bronze Age&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Iron Age&lt;/p&gt;&#xA;&lt;p&gt;etc.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Generally it is estimated that humans evolved on Earth between 200,000 and 300,000 years ago.&lt;/p&gt;&#xA;&lt;p&gt;I know we are homo sapiens, what I am trying to understand is what is the first step for humans. I read about Australopithecus and the &amp;quot;Australopithecus&amp;quot; evolution of the homo on the Earth. I know they are not considered human like us, but, where and when is the first step around the Earth in history where life for humans starts?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.khanacademy.org/humanities/world-history/world-history-beginnings/origin-humans-early-societies/a/where-did-humans-come-from&quot; rel=&quot;nofollow noreferrer&quot;&gt;humans in the earth&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Homo&quot; rel=&quot;nofollow noreferrer&quot;&gt;homo&lt;/a&gt;&#xA;&lt;a href=&quot;http://humanorigins.si.edu/evidence/human-fossils/species/homo-erectus&quot; rel=&quot;nofollow noreferrer&quot;&gt;homo&lt;/a&gt;&#xA;&lt;a href=&quot;https://es.wikipedia.org/wiki/Hominini&quot; rel=&quot;nofollow noreferrer&quot;&gt;info&lt;/a&gt;&#xA;&lt;a href=&quot;https://es.wikipedia.org/wiki/Hominidae&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hominidae&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I am not expert in this topic I hope somebody could give me more information about this question.&lt;/p&gt;&#xA;" OwnerUserId="7701" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-01-08T19:28:47.530" Title="What was there before the Paleolithic and where really did life start for us humans, not like homo?" Tags="|evolution|" AnswerCount="3" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="17877" PostTypeId="2" ParentId="17876" CreationDate="2019-08-30T08:02:26.750" Score="5" Body="&lt;p&gt;Forty years ago, protein electrophoresis and other molecular types of dating were pointing to a date of 4.5 million years BP for the separation of the hominid line from the pongid (great ape) line, but I didn't believe it at the time because it conflicted with the fossil evidence. Since then, more fossils have been found and the disparity between geological dating techniques and molecular analysis has become greater. We now have Ardipithecus kadabba, dated at 6 million years BP, and Sahelanthropus tchadensis at 7 million years BP. These were bipedal hominids which had already split off from the common ancestor of the pongid line which led to modern chimps and gorillas. These early hominids were australopithecine-type creatures, small brained and still essentially bipedal apes, but having many characteristics similar to humans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Exactly when the australopithecines became brainy enough to be classed as humans is to some extent a value judgement and therefore not absolutely clear, but it is generally held that the first human was Homo habilis from Lake Turkana, Kenya, and lived about 3 million years ago. All the most important hominid fossils were found in Africa, mainly East Africa.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Palaeolithic, Mesolithic and Neolithic periods refer to the type of stone tools used by hominids at the relevant times. Palaeolithic tools were very primitive, and it usually takes an expert eye to identify them as tools rather than random fragments. They date from about the time of Homo habilis. It is entirely possible that some of these tools were made by Australopithecines. Mesolithic tools were a bit more sophisticated. and Neolithic tools were made comparatively recently by Homo sapiens and Homo neanderthalensis. The bronze and iron ages belong to the last few thousand years. The Great Pyramid was built in the copper age, 4.5 thousand years ago, which preceded the bronze age. The 200,000 - 300,000-year dates you refer to are the approximate dates of the earliest Neanderthals and the migration of the first Homo sapiens from Africa into the Middle East and Asia. The first Neanderthals closely resembled the African version of Homo erectus,from which they evolved, so it takes an expert to decide which is which.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the end of your question you seem to be asking when did life start. The generally accepted date is around 3.8 billion years ago, but it might have been very slightly earlier.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-30T08:02:26.750" CommentCount="15" ContentLicense="CC BY-SA 4.0" />
  <row Id="17880" PostTypeId="2" ParentId="17604" CreationDate="2019-08-31T03:39:59.120" Score="11" Body="&lt;p&gt;I'm the scientist in the article; someone just saw this question and emailed me about it! (I'm on as a guest here since I don't have an account, so you'll hopefully trust it's me. Even if you don't believe it's me, I hope the answer will still be useful.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's entirely a safety issue. The best way to get around on the surface of the glaciers in this area is to cross-country ski on the snowy surface. If that snow gets thin or melts away completely, it's very risky to be on the glacier because the crevasses in the ice below become exposed. We're all trained in crevasse rescue, but we'd rather no one fall in the first place! My field site normally has ample snow thickness at the time I was there, but an early and extreme heat wave in the area put the whole icefield about a month ahead in the melt season. We did our best getting as much data as possible, but ultimately safety comes first and we had to get out of there.&lt;/p&gt;&#xA;" OwnerUserId="17756" LastActivityDate="2019-08-31T03:39:59.120" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17881" PostTypeId="2" ParentId="9089" CreationDate="2019-08-31T07:37:49.360" Score="2" Body="&lt;p&gt;If organic matter is buried - such as in landfill - it will decay anaerobically, resulting in &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CH_4}$&lt;/span&gt; (methane) rather than &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; (Carbon dioxide). Methane is about 30 times more harmful as a global warming gas. Hence the reason why it is important not to landfill organic matter such as paper, card or waste food. However landfill of plastics (which is generally derived from a fossil fuel) is carbon sequestration, resulting in a net reduction of global warming gasses. So waste must be sorted before incineration - incinerating plastics produces/releases much &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; and drives global warming&lt;/p&gt;&#xA;" OwnerUserId="17757" LastEditorUserId="2470" LastEditDate="2020-01-04T19:29:33.277" LastActivityDate="2020-01-04T19:29:33.277" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17882" PostTypeId="1" CreationDate="2019-08-31T16:13:42.940" Score="2" ViewCount="100" Body="&lt;p&gt;Does oceanic and land mass positioning affect tropical storm evolution in the southern hemisphere? And, do cold fronts migrate latitudinally &quot; upwards &quot; the way they drift &quot;downwards&quot; in the northern?&lt;/p&gt;&#xA;" OwnerUserId="17759" LastActivityDate="2020-01-28T20:02:20.250" Title="Southern Hemisphere climate" Tags="|meteorology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17883" PostTypeId="2" ParentId="17882" CreationDate="2019-08-31T18:25:09.963" Score="-1" Body="&lt;p&gt;The fact that there is much less land mass in the southern hemisphere affects the climate and sea currents, but the situation is otherwise much the same as the northern hemisphere. Cold fronts tend to move north, whereas in the northern hemisphere they tend to move south. Hurricanes and typhoons are less common in the southern hemisphere, especially in the south Atlantic, and drift south, where there is less land to get in their way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cyclonic tropical storms form where ocean waters are heated by tropical or subtropical sun, and this heat is the source of their power. In the north, the Caribbean and Gulf of Mexico are a prime source of hurricanes because the ocean is hemmed in by land and heats up more easily than the south Atlantic. Hurricanes here do more damage and attract more attention than they would in the less populated vastness of southern hemisphere oceans. Just as hurricanes from the Caribbean tend to move north, those forming below the equator in the Indian ocean, where they are called typhoons, tend to drift south toward the vast emptiness of the Southern Ocean.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-08-31T18:25:09.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17884" PostTypeId="2" ParentId="9540" CreationDate="2019-08-31T21:15:58.430" Score="1" Body="&lt;p&gt;Arkaia's answer gives good information on the primary cause, which is the multitude of different astronomical changes that operate on various different timescales.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, there's an additional consideration, which is &quot;storm surge&quot; or, more colloquially, &quot;what the weather is doing&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Differences in atmospheric pressure between different areas can lead to water flowing to those areas with low pressure, and this can make a significant difference (metres) to sea level. The same is true of heavy winds and wave action. Usually this is considered in terms of flooding, and it isn't a tidal process - but it does still affect the elevation of any given high tide.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Storm surge is often discussed with respect to hurricanes, but the more modest pressure differences elsewhere can still have considerable effects.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-08-31T21:15:58.430" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17893" PostTypeId="1" CreationDate="2019-09-01T20:04:49.580" Score="3" ViewCount="175" Body="&lt;p&gt;I'm trying to plot lithological data using the Troels-Smith scheme. I have tried psimpoll but as I only have lithological data I cannot create a main input file which is required. I also do not have access to the plotting graphics in Tilia. All I want to create is a clean lithological diagram. &#xA;Is there a package in R or another opensource/free tool for getting such plots that anyone might be aware of? &lt;/p&gt;&#xA;" OwnerUserId="17774" LastActivityDate="2019-09-01T20:04:49.580" Title="How do I plot Troels-Smith lithological symbols in R?" Tags="|sedimentology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17894" PostTypeId="2" ParentId="7398" CreationDate="2019-09-01T20:50:01.497" Score="2" Body="&lt;p&gt;Only if you factor in relativistic differences! Someone standing on the equator is traveling at about 464 m/s whereas someone standing at 41° Latitude is only traveling at about 350 m/s. Hence the person at the equator would appear to be 4.6E-06 seconds per year slower in time than the person at 41° Latitude.&lt;/p&gt;&#xA;" OwnerUserId="17775" LastEditorUserId="39" LastEditDate="2019-09-02T04:20:28.233" LastActivityDate="2019-09-02T04:20:28.233" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17896" PostTypeId="1" CreationDate="2019-09-01T23:40:44.553" Score="1" ViewCount="39" Body="&lt;p&gt;According to this article, &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://science.howstuffworks.com/environmental/energy/energy-hurricane-volcano-earthquake1.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Energy Hurricane Volcano&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;we find that for a typical mature hurricane, we get numbers in the range of 1.5 x 10^12 Watts or 1.3 x 10^17 Joules/day (this is according to the Atlantic Oceanographic and Meteorological Laboratory.) But that's not all, we're just getting started. A hurricane also releases energy through the formation of clouds and rain (it takes energy to evaporate all that water). If we crunch the numbers for an average hurricane (1.5 cm/day of rain, circle radius of 665 km), we get a gigantic amount of energy: 6.0 x 10^14 Watts or 5.2 x 10^19 Joules/day!&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and according to this article,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://geology.com/hurricanes/largest-hurricane/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The largest and deadliest hurricane to touch United States&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Hurricane Camille of 1969 had the highest wind speed at landfall, at an estimated 190 miles per hour when it struck the Mississippi coast.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;How much energy did Hurricane Camille release, which was one of the largest ones and not an average hurricane?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastEditorUserId="9635" LastEditDate="2019-09-02T04:21:02.967" LastActivityDate="2019-09-02T04:21:02.967" Title="How much energy did Hurricane Camille release?" Tags="|tropical-cyclone|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17897" PostTypeId="1" CreationDate="2019-09-02T02:04:20.410" Score="1" ViewCount="1369" Body="&lt;p&gt;I found this rock today on my property. It looks similar to another rock I saw that was said to be a civil war cannon ball, however comments below suggest that it could be a geode.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Are there any tests I can do &lt;em&gt;short of breaking it in half&lt;/em&gt; to find out if it is a geode?&lt;/li&gt;&#xA;&lt;li&gt;If I wanted to break it into two halves in a nice way (rather than smash it up into several random pieces) how might I do that?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/zgOCo.jpg&quot; alt=&quot;possible geode?&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="17778" LastEditorUserId="6031" LastEditDate="2019-09-05T07:57:55.907" LastActivityDate="2019-09-05T07:57:55.907" Title="How can I find out if this is a geode without breaking it in half?" Tags="|rocks|geode|" AnswerCount="0" CommentCount="5" ClosedDate="2019-09-02T08:08:11.007" ContentLicense="CC BY-SA 4.0" />
  <row Id="17898" PostTypeId="1" CreationDate="2019-09-02T12:35:53.540" Score="3" ViewCount="1221" Body="&lt;p&gt;In the Wikipedia article for the Simpsons Desert in Australia in the first paragraph it says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It is the fourth-largest Australian desert, with an area of &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{176,500}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{km^2}$&lt;/span&gt; (&lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{68,100}$&lt;/span&gt; sq mi) and is the world's largest sand dune desert.&lt;br&gt;&#xA;  &lt;a href=&quot;https://en.wikipedia.org/wiki/Simpson_Desert&quot; rel=&quot;nofollow noreferrer&quot;&gt;Simpson Desert - Wikipedia&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I know that the &lt;a href=&quot;https://en.wikipedia.org/wiki/Rub%27_al_Khali&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rub' al Khali&lt;/a&gt; Desert is the largest sand desert in the world, and as seen in this photo it has sand dunes:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8iSXQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8iSXQ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;This is the Rub' al Khali. The caption for this picture on the article says &quot;Sand dunes to the east of Liwa Oasis&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is another photo of the Rub' al Khali&lt;br&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/0wq3Z.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0wq3Z.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it the case that although the largest sand desert is in southern Arabia and contains sand dunes nevertheless there is another larger &quot;sand dune desert&quot; in Australia? How is this classified? I'm assuming if this is true it means that the  Rub' al Khali Desert doesn't fall into the category of a &quot;sand dune desert&quot;, whatever that is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've seen photos of both and both look very sandy and duney to me. &lt;/p&gt;&#xA;" OwnerUserId="13979" LastEditorUserId="2470" LastEditDate="2020-01-02T19:23:06.053" LastActivityDate="2020-01-02T19:23:06.053" Title="How can the Simpson Desert be the largest sand dune desert in the world?" Tags="|desert|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="17899" PostTypeId="2" ParentId="17898" CreationDate="2019-09-02T13:42:54.340" Score="3" Body="&lt;p&gt;The controversy over the largest sand desert is like the controversy over the longest river. Both Nile and Amazon are often quoted, and I have seen claims for the Mississippi. The Nile is favourite. Photographs of deserts can be misleading unless they are photographed from high above (such as from an aircraft or from space) and show the whole area, because photos from the ground only show a very limited area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just as with rivers, much depends on how you classify what you are comparing. There are different ways of measuring rivers and no doubt different ways of measuring deserts. The largest desert is the Sahara, and it also has the greatest area of sand sea and dunes. It doesn't qualify as the largest area of dunes or sand sea in this context because the sand seas, though large, are not contiguous but are intersected by areas of mountain desert and stony desert. In some deserts the sand sea is interrupted by areas of semi desert in which there is sparse vegetation. Even dunes support sparse vegetation in some places, which compounds the problem of whether they count as dunes. How much vegetation can you allow and still classify it as dune or sand sea?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just as the Nile is the favourite option for longest river, Rub al Khali must be favourite for largest contiguous sand dune desert, and Wikipedia may have got it wrong. But to be sure, we need to know how the Simpson desert was measured. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="1411" LastEditDate="2019-12-07T12:52:58.860" LastActivityDate="2019-12-07T12:52:58.860" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17900" PostTypeId="1" CreationDate="2019-09-02T22:08:46.380" Score="2" ViewCount="223" Body="&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/yXHNS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found this rock in Western Wisconsin. Pretty sure it's a Lake Superior Agate?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wondering what would make the white eye that has red in its center?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would this rock be a good one to have someone cut in 1/2?&lt;/p&gt;&#xA;" OwnerUserId="17784" LastEditorUserId="725" LastEditDate="2019-09-05T05:26:00.763" LastActivityDate="2019-09-05T05:26:00.763" Title="What Makes Round Holes In Superior Agates?" Tags="|geology|" AnswerCount="1" CommentCount="0" ClosedDate="2019-09-03T16:09:22.267" ContentLicense="CC BY-SA 4.0" />
  <row Id="17901" PostTypeId="2" ParentId="17900" CreationDate="2019-09-02T23:09:20.457" Score="2" Body="&lt;p&gt;Agate sometimes contains fossils. Your specimen seems to contain a fossil crinoid disc, and probably there are more than one. Crinoids are plant-like animals anchored to the sea bed, and are sometimes called sea lilies. Many species  became extinct millions of years ago, but a few survive today. The stems of ancient crinoids were made up of stacked discs, rather like the one in your agate. When the crinoids died, their stems often disintegrated, and the discs became scattered. The hole you mention is the hole found at the centre of all crinoid discs. For some reason it did not become full of agate, perhaps because there was a gas bubble or some other obstruction in there. I can't predict what you would find if you cut it in half, that decision is entirely up to you. I think it would probably be best to leave it as it is.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-02T23:09:20.457" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="17902" PostTypeId="1" CreationDate="2019-09-03T05:42:56.587" Score="1" ViewCount="32" Body="&lt;p&gt;I want to study the clouds and its profile which requires some basic observed variables, does anyone knows how and from where we can get the observed liquid water content data. &lt;/p&gt;&#xA;" OwnerUserId="17779" LastActivityDate="2019-09-03T05:42:56.587" Title="From where we get the observed cloud liquid water content data" Tags="|clouds|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17908" PostTypeId="2" ParentId="8242" CreationDate="2019-09-04T01:12:53.187" Score="3" Body="&lt;p&gt;Found in &lt;a href=&quot;https://twitter.com/amazingmap&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://twitter.com/amazingmap&lt;/a&gt; I can't personally vouch for accuracy.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/8QPGL.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;https://twitter.com/amazingmap/status/1027976155700371456&quot; rel=&quot;nofollow noreferrer&quot;&gt;tweet&lt;/a&gt;, several complaints about Antarctica, &quot;wrong pole&quot;, etc.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;New favourite map projection. Hellereal Boreal Triaxial Projection&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/XeQHw.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;https://twitter.com/amazingmap/status/1164221705113526272&quot; rel=&quot;nofollow noreferrer&quot;&gt;tweet&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;World Mercator map projection with true country size and shape added #Map #Maps #Amazingmap #Amazingmaps #Mercator&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2019-09-04T01:12:53.187" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17909" PostTypeId="2" ParentId="17898" CreationDate="2019-09-04T01:31:41.287" Score="4" Body="&lt;p&gt;The linked &lt;a href=&quot;https://en.wikipedia.org/wiki/Simpson_Desert&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia article&lt;/a&gt; has been edited after the OP's question was posted. It now says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Simpson Desert is a large area of dry, red sandy plain and dunes in Northern Territory, South Australia and Queensland in central Australia.&lt;sup&gt;1,2&lt;/sup&gt; &lt;strong&gt;It is the fourth-largest Australian desert, with an area of 176,500 km2 (68,100 sq mi).&lt;/strong&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The desert is underlain by the Great Artesian Basin, one of the largest inland drainage areas in the world. Water from the basin rises to the surface at numerous natural springs, including Dalhousie Springs, and at bores drilled along stock routes, or during petroleum exploration. As a result of exploitation by such bores, the flow of water to springs has been steadily decreasing in recent years. It is also part of the Lake Eyre basin.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;strong&gt;The Simpson Desert is an erg that contains the world's longest parallel sand dunes.&lt;/strong&gt;&lt;sup&gt;3&lt;/sup&gt; These north-south oriented dunes are static, held in position by vegetation. They vary in height from 3 metres (9.8 ft) in the west to around 30 metres (98 ft) on the eastern side. The largest dune, Nappanerica or Big Red, is 40 metres (130 ft) in height.&lt;sup&gt;4&lt;/sup&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;sup&gt;1&lt;/sup&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Charles_Rowland_Twidale&quot; rel=&quot;noreferrer&quot;&gt;Twidale, C.R.&lt;/a&gt; (1980). &quot;The Simpson Desert, central Australia&quot;. &lt;a href=&quot;https://en.wikipedia.org/wiki/South_African_Geographical_Journal&quot; rel=&quot;noreferrer&quot;&gt;South African Geographical Journal&lt;/a&gt;. 65: 3–17.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;sup&gt;2&lt;/sup&gt;&quot;&lt;a href=&quot;https://web.archive.org/web/20080729021024/http://environment.sa.gov.au/parks/pdfs/BROCHURE_DESERT_PARKS.PDF&quot; rel=&quot;noreferrer&quot;&gt;Desert Parks of South Australia&quot; (PDF)&lt;/a&gt;. Department of Environment and Heritage, South Australia. Archived from the original (PDF) on 29 July 2008. Retrieved 23 October 2008. &quot;&lt;a href=&quot;http://www.britannica.com/EBchecked/topic/545465/Simpson-Desert&quot; rel=&quot;noreferrer&quot;&gt;Simpson Desert&lt;/a&gt;&quot;. Britannica Encyclopedia Inc. Retrieved 23 October 2008.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;sup&gt;3&lt;/sup&gt;Madigan, C.T. 1936. The Australian sand-ridge deserts. The Geographical Review 26(2):205-227.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;sup&gt;4&lt;/sup&gt;Rachel Dixon (2018). &lt;a href=&quot;https://books.google.com.tw/books?id=6LBVDwAAQBAJ&amp;amp;lpg=PA23&amp;amp;pg=PA23&amp;amp;redir_esc=y#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;noreferrer&quot;&gt;Deserts &amp;amp; Savannahs in Australia&lt;/a&gt;. Redback Publishing. p. 23. ISBN 9781925630206.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It seems that the article has been corrected on &lt;code&gt;13:13, 2 September 2019&lt;/code&gt; by user‎ Casu Marzu per the &lt;a href=&quot;https://en.wikipedia.org/w/index.php?title=Simpson_Desert&amp;amp;action=history&quot; rel=&quot;noreferrer&quot;&gt;article's history page&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Considering the timing, this is likely to be a direct result of your question. &lt;strong&gt;Good work!&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2019-09-04T01:31:41.287" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17911" PostTypeId="2" ParentId="17489" CreationDate="2019-09-04T12:59:57.033" Score="1" Body="&lt;p&gt;this is probably a little late in the day to answer. I have a wafo &quot;superficially working&quot; on windows 10 with python 3.7.1: however, so far I have only accessed the wave spectrum models. The recipe I used was &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;clone the repo&lt;/li&gt;&#xA;&lt;li&gt;pip install 2to3&lt;/li&gt;&#xA;&lt;li&gt;navigate to the cloned folder&lt;/li&gt;&#xA;&lt;li&gt;2to3 . -w &lt;/li&gt;&#xA;&lt;li&gt;copy folder to src/wafo folder to site-packages/wafo&lt;/li&gt;&#xA;&lt;li&gt;Open cmd.exe or something better e.g. ConEmu&lt;/li&gt;&#xA;&lt;li&gt;Assuming your python.exe is in your PATH. type ... python -c &quot;import wafo&quot;&lt;/li&gt;&#xA;&lt;li&gt;Then address each problem in turn... &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;There aren't many problems to address if all you need are the wave spectrum models. It took me an hour to hack the source code to access these. If you need to access the whole suite of functionality, continue the approach. You may need to recompile the c-libraries if they are needed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sorry I can't provide a comprehensive list of the changes I made to get wafo to import. Here are the ones I remember&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;It will complain about &quot;import scipy.lib.six&quot;. Change to &quot;import six&quot; (install it)&lt;/li&gt;&#xA;&lt;li&gt;It will complain about scipy's piecewisepolynomial. Change to PPoly&lt;/li&gt;&#xA;&lt;li&gt;It will complain some version checks ... set to True as your module versions are no-doubt much newer than the versions 5 years ago. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="17795" LastActivityDate="2019-09-04T12:59:57.033" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17912" PostTypeId="1" AcceptedAnswerId="18570" CreationDate="2019-09-04T13:58:30.903" Score="4" ViewCount="582" Body="&lt;p&gt;&lt;a href=&quot;https://www.pc-progress.com/en/Default.aspx?hydrus-1d&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hydrus-1D&lt;/a&gt;, is a modeling environment for analysis of water flow and solute transport in variably saturated porous media. This program has a graphical environment which works very well, however a lot of input data is needed to prepare for each run. Is it possible to run Hydrus-1D from the commandline in Windows? Assuming that I have generated the input files?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since this is a rather technical question is it recommended to post this on a more technical Stack Exchange site?&lt;/p&gt;&#xA;" OwnerUserId="17796" LastEditorUserId="17796" LastEditDate="2019-09-04T22:45:49.493" LastActivityDate="2019-11-26T04:55:06.640" Title="Run Hydrus-1D from the command line" Tags="|hydrology|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17913" PostTypeId="1" CreationDate="2019-09-04T15:45:08.503" Score="2" ViewCount="596" Body="&lt;p&gt;I want to get an estimate on how cold my pond will get.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is a 1 acre pond in Central Florida USA. It has an average depth of 4 feet. There is not much circulation in the pond. It gets direct sunlight during these cold months. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are the average temperatures (high + low)/2 in Farenheit.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;              °F       °C&#xA;November      65      18.3 &#xA;December      60      15.6&#xA;January       57.5    14.2&#xA;February      60      15.6&#xA;March         65.5    18.6&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;What is the warmest temperature the water will remain? Its not as simple as looking at the numbers and will take some judgement. The top half of the water will certainly be warmer than the bottom, and the 1 foot shallows near the bank will be even warmer due to the direct sun. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fish I am considering putting into this pond will have normal feeding behaviors recommended at 68 degrees but I estimate that it will go into conservation mode and not eat at around 60 degrees or possibly die.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it likely that the fish will be able to find water at or above 68 degrees during these months (on the bank or near the surface for the greater part of the day?) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't have tools to measure the temperature of different parts of the water, and with the large amount of rain we have had lately the temp would be off.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you for any insight.&lt;/p&gt;&#xA;" OwnerUserId="17797" LastEditorUserId="6031" LastEditDate="2019-09-05T08:03:57.297" LastActivityDate="2019-09-05T08:56:05.797" Title="Estimation on how cold will my pond get - intent is to know if certain fish can survive in it" Tags="|meteorology|groundwater|solar-terrestrial-physics|evaporation|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17914" PostTypeId="1" CreationDate="2019-09-04T16:00:16.987" Score="2" ViewCount="1864" Body="&lt;p&gt;I found this geode-like rock (spheroidal shaped with empty spheroidal cavity inside) near Dickson Tennessee, USA. Comments suggest that this is in fact geode, but it is empty and featureless inside. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The white on the outer part is soft and can be flaked off.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Can this still be a geode? Assuming it is, why might this one be empty inside instead of being full of crystals?&lt;/li&gt;&#xA;&lt;li&gt;Would this be indicative that most geodes in this area are likely to be empty as well, or would there be no correlation between one and another?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Click any image for full-size view, scale is in inches:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dW4gB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dW4gBm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/Bukbl.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Bukblm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/KDwWJ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KDwWJm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/WNzTm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WNzTmm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/b6OWh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/b6OWhm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/j0xQt.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/j0xQtm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/nfyc6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nfyc6m.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/i1vPi.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/i1vPim.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17798" LastEditorUserId="6031" LastEditDate="2019-09-05T07:47:05.380" LastActivityDate="2019-09-05T10:02:23.560" Title="Geode-like rock but it's empty inside. Why does this happen?" Tags="|crystals|geode|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17915" PostTypeId="1" AcceptedAnswerId="19545" CreationDate="2019-09-04T20:37:17.143" Score="4" ViewCount="305" Body="&lt;p&gt;&lt;a href=&quot;http://www.ceri.memphis.edu/people/rsmalley/CERI7280F2016/PLATE%20TECTONICS.html&quot; rel=&quot;noreferrer&quot;&gt;Euler's &quot;fixed point&quot; theorem ... can be stated as&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The most general displacement of a rigid body over the surface of a&#xA;  sphere can be regarded as a rotation about a suitable axis which&#xA;  passes through the centre of that sphere.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Thus all plate motions can be described by a rotation axis, which passes through the centre of the Earth and cuts the surface at two points, called the poles of rotation. The relative motion of two plates then needs a pole of rotation and an angular velocity to be defined.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So where are those poles located?  Is there any map or resource indicating where those are 'poles' are?&lt;/p&gt;&#xA;" OwnerUserId="17801" LastEditorUserId="725" LastEditDate="2019-09-05T05:23:45.693" LastActivityDate="2020-05-02T14:05:40.627" Title="where are the poles of rotation of the tectonic plates located?" Tags="|geology|geophysics|plate-tectonics|planetary-science|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17917" PostTypeId="2" ParentId="17913" CreationDate="2019-09-04T22:24:26.980" Score="1" Body="&lt;p&gt;I doubt a pond temperature will stay above 60 in central FL winter.Without circulation there will be large temperature gradients caused by stratification, especially on warm days. Surface plants probably lower the maximum temperatures. For such a large pond ,the relative humidity and wind will make a temperature difference ( evaporation is a major heat loss).  As a comparison , I have a small ( 1000 gal) pond with circulation and although our air temperatures are usually 98 -day and 76-night, I have never measured a temperature over 83 F and usually lower. So the water temperature is definitely lower than the average air temperature in summer. In winter I protect my pond from low temperatures but it gets to 52 F . However, tropical fish like danios, swordtails and mollies survive that temperature in pond conditions , although books will say such temperature will kill them . What fish do you plan to have ? With the history that FL has for raising tropical fish , I would think there would be information available , such as from the FL Dept of Agriculture.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2019-09-04T22:24:26.980" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17918" PostTypeId="2" ParentId="17913" CreationDate="2019-09-05T04:46:55.640" Score="1" Body="&lt;p&gt;Your fish will be fine even in the coldest months of the year,And they will not stop eating if the temparature gets lower but their digestion of the food do slow down at the low temparatures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the coldest part ot the year the temparature at the bottom of a one and a half metres deep pond will stay at or close to the average temparature in your area,and the surface water will get a significantly higher temparature during the day and evening.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you take a look at the native area of your fish you will find the type of climate they are adapted to(look at the day/night temparature)The fish can often live well outside of this temparature range.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sorry for not answering what temparature you will have in your pond,there is a lot of things that can change the temparature in a small body of water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the water in your pond are at 20C and you replace half of this with 10C rainwater you will only change the temparature by 5C(not totaly correct but close,it is for water that is fully mixed and not for the temparature layers you might see in a pond).&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6258" LastEditDate="2019-09-05T08:56:05.797" LastActivityDate="2019-09-05T08:56:05.797" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17919" PostTypeId="2" ParentId="17914" CreationDate="2019-09-05T10:02:23.560" Score="1" Body="&lt;p&gt;Geodes form where there is a gas bubble or some other sort of cavity in volcanic or sedimentary rocks. I once found scores of them eroding out of a sea cliff in Oman, and they looked very similar to yours. I can tell that your geode was formed in sedimentary rock like mine were. What happens is that over millions of years, water seeps in, sometimes bringing in sand and clay particles which line the cavity when it occurs in sedimentary rock. This mineral rich water, sometimes from hydrothermal sources, seeps into the cavity and precipitates various minerals, mostly silicon dioxide, around the sides of the hollow. This usually results in a lining of quartz crystals, but can produce amethyst or opal, both of which are composed of silicon dioxide. Very rarely, opalized fossils are found inside geodes. As for your empty geode, I presume that either the necessary seepage of mineral-laden water never happened, or it never had time to happen. The process takes millions of years.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-05T10:02:23.560" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17920" PostTypeId="1" CreationDate="2019-09-05T11:28:59.323" Score="2" ViewCount="127" Body="&lt;p&gt;Can fissure eruptions dislocate/deform ( fault, rotate, bend, folding) the surrounding strata which fissure ascending into.&#xA;Or, &#xA;can a laccolith reach to the surface (and flow) after folding the surrounding strata?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;( the magmatic rock on the photo is dacite-rhyodacite according to geochemical analysis)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TUqNP.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TUqNP.jpg&quot; alt=&quot;pi&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="15195" LastEditDate="2019-09-10T19:32:27.863" LastActivityDate="2019-09-19T20:35:38.973" Title="Fissure eruption" Tags="|igneous|volcanic-eruption|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17921" PostTypeId="2" ParentId="17920" CreationDate="2019-09-05T12:39:10.297" Score="1" Body="&lt;p&gt;A fissure eruption can dislocate and cause faults in surrounding strata, but these strata are not plastic enough to be bent and folded in the short term. Strata can be bent and folded, but only if subjected to the sort of pressures exerted by plate movements at great depth over millions of years. Fissure eruptions can reach the surface and flow, but will not bend or fold the strata encountered on the way, though they might fracture it.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-05T12:39:10.297" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17922" PostTypeId="1" CreationDate="2019-09-05T18:49:57.143" Score="1" ViewCount="57" Body="&lt;p&gt;It is 9 1/2 inches by 3 1/2 inches and weighs about 5 lbs. it was at this house in Florida when we bought it. It has a white 1/4 inch crust and the interior color looks somewhat topaz. &lt;img src=&quot;https://i.stack.imgur.com/kUhhm.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="17805" LastActivityDate="2019-09-06T03:44:57.390" Title="Could someone tell me what this stone might be" Tags="|geology|" AnswerCount="1" CommentCount="3" ClosedDate="2019-09-06T18:06:54.593" ContentLicense="CC BY-SA 4.0" />
  <row Id="17923" PostTypeId="2" ParentId="17922" CreationDate="2019-09-05T19:02:58.623" Score="2" Body="&lt;p&gt;Most likely some form of chalcedony, not knowing where you found it, I'd call it flint, a form of chert. &lt;/p&gt;&#xA;" OwnerUserId="17806" LastActivityDate="2019-09-05T19:02:58.623" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17924" PostTypeId="1" CreationDate="2019-09-05T20:18:08.007" Score="3" ViewCount="42" Body="&lt;p&gt;Dorian is currently passing over the Carolinas but its eye is only brushing the shore. However there's a side of Dorian that isn't raining:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/MGgZ5.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this unique to Dorian?&lt;/p&gt;&#xA;" OwnerUserId="13400" LastActivityDate="2019-09-05T20:18:08.007" Title="Why isn't Dorian raining on the southeast side?" Tags="|tropical-cyclone|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17927" PostTypeId="1" CreationDate="2019-09-06T10:48:49.367" Score="4" ViewCount="559" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MdHcj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MdHcj.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;Can you assist me in understanding how this hollow was formed in this rock. I am told that it has to do with cementation but I believe that geological process produces rounded canonball ( sometimes ) like stones. Is this some sort of hollow ( or reverse ) cementation ? I have also been informed that it was likely formed beneath the surface when the sandstone was forming into rock and it is a completely distinct process from that which the rock has since undergone when it has been exposed to weathering on the surface.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/AVl4o.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AVl4o.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17812" LastEditorUserId="17812" LastEditDate="2019-09-06T11:49:56.010" LastActivityDate="2019-09-06T12:54:09.110" Title="How did this hole / hollow form within this rock?" Tags="|geology|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="17928" PostTypeId="2" ParentId="17927" CreationDate="2019-09-06T12:54:09.110" Score="1" Body="&lt;p&gt;It looks to me that there were voids in this rock when it was formed, caused by gas bubbles These voids might have become filled with sand or other friable material. Weathering eroded the side of the hollow, enlarging it and allowing any finely divided material inside it to trickle out. You should have included something to show scale, but my impression is that your rocks are about six feet tall and not very solid, therefore easily eroded. The round stones you refer to are geodes, which are hollow and usually encrusted in the inside with quartz crystals. In some parts of England they are referred to as 'potato stones', which gives you an idea of what they look like. Some recent posts on this site give you photos of them.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-06T12:54:09.110" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17929" PostTypeId="1" AcceptedAnswerId="19114" CreationDate="2019-09-06T13:21:18.317" Score="4" ViewCount="816" Body="&lt;p&gt;Haze is not considered to be a cloud or mist, and it also is not fog.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the ultimate reason that haze and general poor visibility ranges prevail in stable atmospheric conditions?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the cause concentration of pollutants, some other effect caused by the presence of moisture/humidity, a combination of both, or something else completely?&lt;/p&gt;&#xA;" OwnerUserId="6242" LastActivityDate="2020-02-04T05:09:06.363" Title="Why does haze and poor visibility present in stable air?" Tags="|atmosphere|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17930" PostTypeId="2" ParentId="17929" CreationDate="2019-09-06T14:15:09.110" Score="-1" Body="&lt;p&gt;Haze can have a number of causes. Sometimes it is due to moisture in the atmosphere, but not sufficient to form clouds, and sometimes it is due to pollution. In Britain it can on rare occasions be caused by dust picked up from the Sahara desert and carried northwards. As you suggest, it can sometimes be due to a combination of causes. In heavily polluted London, many years ago, the lunchtime winter sun was so reddened with pollution haze that I was easily able to see sunspots with the naked eye. These were special circumstances, and I wouldn't advise anyone to try it nowadays.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-06T14:15:09.110" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17932" PostTypeId="2" ParentId="17929" CreationDate="2019-09-06T20:57:12.570" Score="0" Body="&lt;p&gt;Haze consists mostly of aerosols. To which extent varies on the location and conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Aerosols are for example dust, pollen, particulate matter, ash (or other pollutants due to combustion) and... a lot of other stuff. Basically, anything which is ligthly enough to float in the air and small enough to mostly not be seen by the naked eye (dust/sand are an exception).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Aerosols function as condensation cores for water vapor - so if there is rather dry air and no rain, no aerosols are &quot;washed&quot; from the atmosphere and haze builds up. In special weather conditions (inversions aka next to no wind and no convection) the haze becomes very thick and a health hazard (e.g. Victorian London, today Delhi or Beijing or Stuttgart).&lt;/p&gt;&#xA;" OwnerUserId="14194" LastActivityDate="2019-09-06T20:57:12.570" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17934" PostTypeId="1" AcceptedAnswerId="17944" CreationDate="2019-09-07T09:48:50.250" Score="1" ViewCount="181" Body="&lt;p&gt;Recently a line from a &lt;a href=&quot;https://timesofindia.indiatimes.com/city/kolkata/aquifer-was-not-detected-earlier-metro-engineers/articleshow/70939474.cms&quot; rel=&quot;nofollow noreferrer&quot;&gt;news article&lt;/a&gt; about an aquifer in the path of a tunnel boring machine for Metro networks caught my attention:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Ahead of tunnelling, the builders conduct hydrogeology, a study of water flow in aquifers and characterization of&#xA;  aquifers. During our study, the aquifer wasn’t identified,” said an engineer.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This led me to wonder how aquifers and underground water flow are detected, studied and mapped out. I searched the net but couldn't find anything relevant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, &lt;strong&gt;how are aquifers detected and their courses mapped?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="16954" LastActivityDate="2019-09-09T15:21:23.680" Title="How are aquifers found and traced?" Tags="|hydrology|hydrogeology|underground-water|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17935" PostTypeId="2" ParentId="17375" CreationDate="2019-09-07T10:24:30.720" Score="4" Body="&lt;p&gt;The Beta effect describes how the Coriolis force affects fluid motion depending on spatial changes due to the curvature of the Earth. In other words, it describes the variation of the Coriolis parameter with latitude. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One can model this change exactly or approximate it via Taylor series expansion at a given latitude. The latter option is typically used to make the theoretical analysis of geophysical phenomena possible because the equations are easier to solve. This is the Beta plane approximation, where the Coriolis parameter varies linearly in space.&lt;/p&gt;&#xA;" OwnerUserId="200" LastActivityDate="2019-09-07T10:24:30.720" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17936" PostTypeId="2" ParentId="17934" CreationDate="2019-09-07T13:20:10.087" Score="1" Body="&lt;p&gt;Aquifers are detected by boreholes or by water divining. Water divining is a very unscientific method which so far has no rational explanation, yet is often successful. I put this down to the fact that Britain is such a wet country that wherever you drill a borehole you are almost bound to discover water sooner or later. Perhaps a more scientific explanation for the success of water diviners may yet be found.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An aquifer needs an underlying area of impermeable or semi-permeable rock overlain by strata which are sufficiently fractured or granular that vast quantities of water can pass through them and be stored. Therefore, once you know the geology of a given area you can make a pretty good guess as to where water will be found. However, as your example shows,it is difficult to be absolutely certain where you will strike water,especially where you are dealing with limestone rock. With limestone it is possible to have a dry borehole when there is a substantial underground stream only yards away. Cavities in limestone erode in a random and unpredictable way.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-07T13:20:10.087" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17942" PostTypeId="1" CreationDate="2019-09-08T20:32:41.480" Score="1" ViewCount="44" Body="&lt;p&gt;I've a basic misunderstanding about the formation of tropic cyclones. From the absolute point of view, cyclones form in order to conserve total angular momentum - air masses at different latitudes have different specific angular momentum due to earth rotation (their distance from the earth's axis of rotation is different), so when a low pressure system forms, radial air flow towards the center has to rotate (in the rotating-earth frame of reference) cyclonicaly in order to conserve angular momentum. Putting it in a different point of view, the Coriolis force deflects the radial  winds to create the &quot;tropic cyclone&quot; system.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What i don't understand is this: one can say that the circulation system has angular momentum in the direction of the local vertical at the eye of the storm (it's local zenith direction). But such angular momentum vector has component in a direction perpendicular to the earth rotation axis! so it cannot conserve angular momentum. So what am i missing here? is it something in my basic understanding of the Coriolic force? or maybe my knowledge of the physical structure of the storm is lacking something.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd also like to know if there are models that predict maximal tropic storm size as function of latitude. I read the thermodynamic model in wikipedia excellent article on tropic storm, but this model gives upper bound about wind speed and specific rate of energy production (rate of energy production per unit area of sea surface), and doesn't give information about the size of the storm. I think that for estimating sizes one needs to use mechanical conceptions.&lt;/p&gt;&#xA;" OwnerUserId="17830" LastActivityDate="2019-09-08T20:32:41.480" Title="Question about the physics of hurricanes" Tags="|meteorology|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="17944" PostTypeId="2" ParentId="17934" CreationDate="2019-09-09T15:21:23.680" Score="4" Body="&lt;p&gt;Aquifers are relatively permeable zones of material that transmit water. Common aquifer materials include layers of unconsolidated sedimentary rock, like sands and gravels; and poorly cemented “bedrock” units like sandstone. Interconnected solution cavities in limestone, called karst, are common in some areas. Calling something an “aquifer” generally infers that the unit is capable of producing enough water via a well to be of interest to humans. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Aquifers are typically delineated using geologic and geophysical logs of boreholes from wells and test holes. These kinds of logs are typically required to be provided to a specified public agency for future use by others. Using these logs, a geologist can create cross sections of an area to evaluate the extent and thickness of these units. This is done keeping in mind the geometry of how these were originally deposited, such as linear streams, sheet-like sands, etc.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Surface geophysical techniques can also be used to assess subsurface conditions, but typically require “ground truth.” I remember asking a geophysicist what his data were telling him about an area, and he said, “I won’t know until you put some drill holes in.” It wasn’t as bad/funny as it seem. He could help color in between the data points, but first he needed to know what the specific geophysical response he was seeing meant as far as real rock present in the subsurface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It should be rare to hit an aquifer zone unknowingly, as you described. It’s possible they hit a permeable fault zone, which can be tricky to know about beforehand. But I need to mention that engineers are notorious for keeping geologists out of the loop until a problem arises. They often don’t want to pay for upfront studies, the kind that geologists use to assess such things.&lt;/p&gt;&#xA;" OwnerUserId="17833" LastActivityDate="2019-09-09T15:21:23.680" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17945" PostTypeId="2" ParentId="17920" CreationDate="2019-09-09T15:42:51.963" Score="2" Body="&lt;p&gt;A fissure eruption typically occurs in basaltic terrain, where the magma is relatively fluid. Hawaii is a great example. Fissure eruptions occur along dilated fault zones. You show a picture of an andesitic unit. This magma has a much different chemistry than basalt, and is generally found in a different geologic terrain, like a convergent plate margin (Japan, South America.) Basalt might form a sill in certain conditions, but not a laccolith. Andesite and granite laccoliths are more common since these magmas are much more viscous/stiff.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Laccoliths almost by definition deform surrounding country rock, the degree to which they do this depends on the size and depth of the laccolith. If the magma from a laccolith reaches the surface it results in a dome or other volcanic ejecta. This portion of the magmma system would not be referred to as a laccolith. It has a root that is a laccolith, but the surface materials have other names.&lt;/p&gt;&#xA;" OwnerUserId="17833" LastActivityDate="2019-09-09T15:42:51.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17946" PostTypeId="2" ParentId="17769" CreationDate="2019-09-09T15:53:24.683" Score="2" Body="&lt;p&gt;I am not sure those are pegmatites. They may simply be granitic dikes. But in either case, you would need to assess the regional geology to look for potential sources of this material, which would be a granitic type magma of younger age than the host rock. You could then map out the size, orientation, and frequency of these dikes to tie them back into their parent unit. Geochemical fingerprinting and age dating could help, too. But there is no way to look at that picture, or a given outcrop, and tell the direction. Remember that the geometry of the third dimension, the one in and out of the picture or outcrop, always needs to be kept in mind and is typically unknown.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am pretty sure it was not top down, though!&lt;/p&gt;&#xA;" OwnerUserId="17833" LastActivityDate="2019-09-09T15:53:24.683" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17947" PostTypeId="2" ParentId="17807" CreationDate="2019-09-09T16:09:15.817" Score="2" Body="&lt;p&gt;It’s relative motion that matters. So in your case, I assume one side is moving faster than another, so you would have a right lateral or left lateral transform fault depending on which side is moving faster. It’s “significance” would depend on the amount of relative difference in motion and, as usually defined, its potential impact on man.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that if they are moving at the same rate there would be no fault (and therefore no boundary.) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There has to be relative movement of the two plates towards one another for it to be “convergent.” Convergent plate boundaries are where one plate is being subducted (e.g. Japan) or pushed against (e.g. Himalayas) another. Having a combination of movements is not really uncommon, but typically of secondary importance. Good example this situation exist along the San Andreas Fault where it locally bends a bit, adding localized convergent components to what is an overall transform fault system. &lt;/p&gt;&#xA;" OwnerUserId="17833" LastEditorUserId="17833" LastEditDate="2019-09-09T16:19:17.413" LastActivityDate="2019-09-09T16:19:17.413" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17948" PostTypeId="1" AcceptedAnswerId="17952" CreationDate="2019-09-09T17:45:06.790" Score="1" ViewCount="121" Body="&lt;p&gt;This article,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.eduplace.com/kids/hmsc/3/f/cricket/cktcontent_3f142.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Old Cold: Living in Ice Age America&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;claims the average Earth temperature during the Ice Age was 12 degrees colder than today. Is this true? How much did temperature vary during the Ice Age?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastActivityDate="2019-09-09T19:02:21.710" Title="How much did temperature vary during the Ice Age?" Tags="|ice-age|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17949" PostTypeId="1" CreationDate="2019-09-09T17:54:19.130" Score="1" ViewCount="532" Body="&lt;p&gt;This article,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://faculty.ucr.edu/~legneref/bronze/climate.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth's temperature in the past 18,000 years&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;seems to show Earth temperature during 5000-3000 years ago was approximately a degree hotter than today. Is this true, were there times during human inhabited Earth were Earth average temperature was hotter than today? If so, were there other moments not listed in that graphic from former times?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastEditorUserId="2470" LastEditDate="2019-09-09T18:03:46.773" LastActivityDate="2019-09-10T10:34:14.417" Title="Were there times during human inhabitated Earth were Earth average temperature was hotter than today?" Tags="|temperature|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17950" PostTypeId="2" ParentId="16753" CreationDate="2019-09-09T18:04:00.270" Score="3" Body="&lt;p&gt;If it’s hot enough to alter the groundwater chemistry that is killing the trees, then you would see it in satellite thermal imaging. Remember, tree roots only go down about 20 to 30 feet at the most, so this is all pretty shallow stuff. This is actually quite a strong thermal anomaly. Like you said, the heat alone may have killed the tree/tree roots.the white areas of the photos are likely salt deposits from the thermal water left behind after evaporation. So again, the thermal water is shallow, indeed, it’s right at the surface. Pretty cool.&lt;/p&gt;&#xA;" OwnerUserId="17833" LastActivityDate="2019-09-09T18:04:00.270" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17951" PostTypeId="2" ParentId="17949" CreationDate="2019-09-09T19:00:39.650" Score="2" Body="&lt;p&gt;Answers would be &quot;no&quot; and &quot;no.&quot; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That graphic isn't sourced, but it appears to refer to the Mid-Holocene Warm Period, roughly 7,000 to 5,000 years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ncdc.noaa.gov/global-warming/mid-holocene-warm-period&quot; rel=&quot;nofollow noreferrer&quot;&gt;According to NOAA&lt;/a&gt; and other sources, the warming of the Mid-Holocene Warm Period was limited to part of the Northern Hemisphere; some regions would have been warmer than today, but not the globe:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It appears clear that changes in Earth's orbit have operated slowly&#xA;  over thousands and millions of years to change the amount of solar&#xA;  radiation reaching each latitudinal band of Earth during each month.&#xA;  These orbital changes can be easily calculated and predict that the&#xA;  &lt;strong&gt;Northern Hemisphere&lt;/strong&gt; should have been warmer than today during the&#xA;  mid-Holocene in the summer and colder in the winter.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This graphic from the NOAA page cited above shows the estimated mid-Holocene temperature anomalies (variation from mean).&#xA;&lt;a href=&quot;https://i.stack.imgur.com/41jky.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/41jky.jpg&quot; alt=&quot;Model-data comparison of surface temperature anomalies for the mid-Holocene (average of 5,500 to 6,500 years ago).&quot;&gt;&lt;/a&gt; Though humans had migrated widely the period, relatively few would have been living outside that cooler blue band.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Were there earlier warmer periods for modern-ish humanity before that? No, since earth was emerging from a glacial period starting about 11,500 years ago, and global average temperatures were gradually rebounding from about 6 degree Celsius cooler than today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The next previous warm era would have been the &lt;a href=&quot;https://en.wikipedia.org/wiki/Eemian&quot; rel=&quot;nofollow noreferrer&quot;&gt;Eemian interglacial period&lt;/a&gt; about 130,000 years ago, which again was associated with orbital variations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could quibble about the era of &quot;human-inhabited&quot; earth; &lt;em&gt;homo sapiens&lt;/em&gt; arose about 300,000 years ago, but remained limited to Africa until about 70,000-50,000 years ago.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastEditorUserId="7314" LastEditDate="2019-09-09T20:22:56.847" LastActivityDate="2019-09-09T20:22:56.847" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17952" PostTypeId="2" ParentId="17948" CreationDate="2019-09-09T19:02:21.710" Score="1" Body="&lt;p&gt;Your article says an ice age was 12F (or about 6C) colder, while other sources quote 10C colder, so there is not complete agreement on how much colder an ice age was compared to the present day. This is not particularly surprising, as there were no meteorologists making careful records in those days. Temperatures for ancient times have to be measured in very indirect and roundabout ways, for example by measuring the ratio of deuterium to hydrogen in ice cores, and there are other vaguely similar ways, all subject to error.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All that is necessary to develop an ice age is that more snow and ice should form during the winter than can be melted away during the summer. This doesn't require a dramatic fall in temperature, and if it continues for long enough you will have an ice age. After a while, of course, the increased area of snow will reflect more of the sun's heat back into space, thus increasing the extent of the ice and the amount of heat reflected away in a sort of feedback mechanism.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-09T19:02:21.710" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17957" PostTypeId="1" CreationDate="2019-09-10T10:08:09.873" Score="1" ViewCount="43" Body="&lt;p&gt;click-&gt;&lt;a href=&quot;http://gpe.letsgrow.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://gpe.letsgrow.com/&lt;/a&gt;&#xA;next click-&gt;moisture transport&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the results of Moist transport through the crop, what is the relationship between crop height and diffusion, air movement, and total water transport? Are there any formulas between them that can express the relationship?&lt;/p&gt;&#xA;" OwnerUserId="17838" LastActivityDate="2019-09-10T10:08:09.873" Title="How does this calculate the water transport between crops in the webside?" Tags="|atmosphere|humidity|greenhouse-gases|moisture-flux|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17958" PostTypeId="1" CreationDate="2019-09-10T20:22:58.330" Score="2" ViewCount="130" Body="&lt;p&gt;Old permafrost is loaded with frozen vegetation.  As it now melts, it is rotting and releasing methane.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Doesn't that mean that it froze quickly, centuries ago, and stayed frozen until now?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What process caused such a sudden, centuries-long freeze? Don't we need to know this before we understand why it's reversing now? Presumably we humans had nothing to do with the freeze!  &lt;/p&gt;&#xA;" OwnerUserId="17842" LastEditorDisplayName="user12525" LastEditDate="2019-09-12T05:06:51.470" LastActivityDate="2022-09-02T13:35:06.577" Title="The origin of permafrost" Tags="|soil|methane|permafrost|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17959" PostTypeId="2" ParentId="17958" CreationDate="2019-09-10T21:53:01.590" Score="-1" Body="&lt;p&gt;Vegetation in Arctic and sub-Arctic bogs is not necessarily rotting. After a while the vegetation in a bog creates an acidic environment that preserves plant material and animal remains as though they were pickled in vinegar. That is why in Britain and Ireland there are extensive peat bogs many thousands of years old, and coal deposits which began in a similar way. In dryer places it is possible for plants and animals to be suddenly overwhelmed by winter conditions and to stay frozen for thousands of years, and these might generate CO2 and methane when they are frozen out. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A famous example of quick freezing is the bronze age warrior known as the Ice Man, who was found about 15 years ago frozen in the Italian Alps where he was overcome by a snow storm when he tried to cross in about 3,000 BC. So the answer is that some of this vegetation froze quickly, but most of it didn't, or at least was already preserved when it froze. It is possible that there have been brief episodes of thawing since then, so the freezing was not necessarily continuous. Some will decompose when it thaws completely, and some won't.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-10T21:53:01.590" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17960" PostTypeId="1" AcceptedAnswerId="17961" CreationDate="2019-09-11T09:54:08.743" Score="1" ViewCount="193" Body="&lt;p&gt;&amp;nbsp;I studied oceanography many years ago at university and recall a lecturer claiming that submarines in the second world war could pass undetected through the entrance to the Mediterranean. &lt;br&gt;&lt;br&gt;&amp;nbsp;He claimed that the halocline caused by the different salinities of the Atlantic and Mediterranean seas would be enough to deflect sonar thus making the submarine invisible. Has anyone seen evidence to support this?&lt;/p&gt;&#xA;" OwnerUserId="17751" LastActivityDate="2019-09-11T11:09:32.210" Title="The halocline and sonar" Tags="|oceanography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17961" PostTypeId="2" ParentId="17960" CreationDate="2019-09-11T11:09:32.210" Score="5" Body="&lt;p&gt;Because of the limitations of wartime sonar, U-boats could sometimes pass undetected into the Mediterranean through the Straits of Gibraltar, but it was always risky and avoiding detection couldn't be guaranteed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There were many things that limited the efficiency of sonar (or ASDIC as the British called it). It is true that sea water has a tendency to separate itself into layers which sonar finds difficult to penetrate. Sometimes this layering was based on differences in salinity, sometimes on differences in temperature, and sometimes on intervening sea currents. Even ships wakes could deflect the sonar beam, so sometimes powerful curving wakes were deliberately made by the U-boat to shake off a pursuing warship.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The range of active sonar under good conditions was normally a few miles, but that could be reduced if there was a lot of background noise. The Gibraltar straits are about 12 miles wide.  Whales and schools of fish could also send back false echoes which would fool all but the most experienced sonar operators.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-11T11:09:32.210" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17963" PostTypeId="1" AcceptedAnswerId="17964" CreationDate="2019-09-11T19:03:05.933" Score="1" ViewCount="250" Body="&lt;p&gt;All I've heard until now is that when the Earth was very hot and slimy, the relatively heavier elements went down to the center of the Earth to form the core. But lately I've come up a contradiction or something. They say the gravity of the very center of the Earth is 0 because you'd get pulled from all the other directions. Then how did the heavier elements go down all the way to the bottom which shouldn't be the place that had strongest gravity?&lt;/p&gt;&#xA;" OwnerUserId="17845" LastActivityDate="2019-09-12T06:18:31.653" Title="How was the Earth's core made?" Tags="|core|gravity|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17964" PostTypeId="2" ParentId="17963" CreationDate="2019-09-11T22:50:54.867" Score="2" Body="&lt;p&gt;When the Earth was newly formed by collisions with asteroids, comets, planetesimals and other debris of the early solar system 4.6 billion years ago, the planet was incandescent and the mantle hotter and more fluid than it is today. Just as you have heard, the heavy metals sank toward the centre.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And just as you say, there is a tiny place at the very centre where almost all the mass of the Earth and therefore almost all the gravity is outside this central point. Imagine this central point to be a cannonball. There is no enormous mass at its centre, pulling it down, and the gravitational field of the mass above it is pulling it outward and upward, so why doesn't it migrate back toward the surface?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You need to remember that only the imaginary cannonball is in this exclusive central position. For any substance close to it but not at the absolute centre, there will be more mass to one side of it than the other, so there will be a gravitational force pulling it toward that direction, in other words, toward the centre of mass. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other thing to remember is that on top of the imaginary cannonball, in all directions, is a column of molten material reaching nearly 4,000 miles right up to the surface, and this column has enormous weight and pressure. Because of this pressure there is a substantial region where the iron-nickel core is solid. How did infalling heavy metals reach the centre if there is a solid mass there? Well,it wasn't always solid, and there was a stage when it was liquid. The gravity-free zone at the Earth's centre is purely theoretical and doesn't allow the centre to behave as though it were in zero gravity.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-09-12T06:18:31.653" LastActivityDate="2019-09-12T06:18:31.653" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17965" PostTypeId="1" AcceptedAnswerId="17966" CreationDate="2019-09-12T00:00:42.343" Score="1" ViewCount="891" Body="&lt;p&gt;How can the radiometric dating of different meteorites determine the age of the earth? Wouldn't radioactive decay have already been occurring in all of those  meteorites long before they hit earth? Wouldn't dating only show when the unstable nuclides in that meteorite were created, not when the earth was created? If you went and measured a decaying nuclide in a metiorite which had traveled for 500 million years before striking earth, then the dating of that metiorite would not tell us the age of the earth it would instead give us an age measurement at least 500 million years older then the earth actually is because that nuclide was decaying long before it managed to hit earth's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also assuming this does somehow get accounted for, how would determining the age of all these various meteorites allow us to estimate the earth's age? Wouldn't this only give us a lower bound on the earth's age? How do we know there doesn't exist some older meteorite out there indicating the earth is older then 4.5 billion years?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;This is not a duplicate of the question asking about why measure meteorites not rocks, I am talking about meteorites and my question is regarding how dating can take into account when the rocks became part of earth as opposed to when the nuclides being dated first came into existence. Its not like the unstable nuclides within a metiorite suddenly decided to start decaying when they hit earth. They started decaying the minute they came into existence, including the time before they hit earth.&lt;/p&gt;&#xA;" OwnerUserId="17847" LastEditorUserId="17847" LastEditDate="2019-09-12T01:11:02.750" LastActivityDate="2019-09-12T01:25:02.280" Title="How can radiometric dating of meteorites determine the age of the earth? Wouldn't this only determine the age of the decaying nuclide in each rock?" Tags="|earth-history|radioactivity|dating|planetary-formation|" AnswerCount="1" CommentCount="1" ClosedDate="2020-06-23T17:40:29.963" ContentLicense="CC BY-SA 4.0" />
  <row Id="17966" PostTypeId="2" ParentId="17965" CreationDate="2019-09-12T01:10:54.707" Score="2" Body="&lt;p&gt;Many of your questions are answered in this question and associated answers:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/2830/725&quot;&gt;Why is Earth&amp;#39;s age given by dating meteorites rather than its own rocks?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To add to some of your other questions:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Wouldn't radioactive decay have already been occurring in all of those meteorites long before they hit earth or our moon?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes. We have an assumption that the Earth formed at about the same time as the meteorites. The age obtained for meteorites is not the time when they hit the Earth, it is the time when they formed. Which is reasonably assumed to be close to the age of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Wouldn't this only give us a lower bound on the earth's age? How do we know there doesn't exist some older meteorite out there indicating the earth is older then 4.5 billion years?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Because we haven't found one. We have found thousands of meteorites and none have an age older than that. Yea, there could be something that we simply having found. But the more you look, the more a pattern emerges.&#xA;Furthermore, there are other systems like &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiometric_dating#The_26Al_%E2%80%93_26Mg_chronometer&quot; rel=&quot;nofollow noreferrer&quot;&gt;26 Mg-Al&lt;/a&gt; which do not date &lt;em&gt;how long ago&lt;/em&gt; things formed, but rather &lt;em&gt;how soon after&lt;/em&gt; the supernova things formed. This allows us to know that meteorites that formed 4.5 billion years ago, also formed within a few million of years after the supernova that made the nebula and all materials in the solar system. Therefore, Earth could not be older than 4.5 billion years.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Al-26 forms abundantly in supernovae and is radioactive with a half-life of almost a million years. Minerals which contain both Mg and Al (such as spinel: MgAl&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;4&lt;/sub&gt;) will initially incorporate Al-26 which will then decay to stable Mg-26. When measured, the mineral will have an excess of Mg-26 relative to what is expected, and then it can constrain its formation time to the time when Al-26 was still around (without a few million of the supernova). The same meteorite can then be dated using other methods (usually U-Pb) to determine how long &lt;em&gt;ago&lt;/em&gt; it formed, and the answer is usually ~4.5 billion years.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2019-09-12T01:25:02.280" LastActivityDate="2019-09-12T01:25:02.280" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="17967" PostTypeId="2" ParentId="17958" CreationDate="2019-09-12T03:34:41.027" Score="4" Body="&lt;p&gt;What caused a centuries long freeze, the beginning of the current ice age. Yes we are in an ice age, as long as greenland and antarctica have large ice sheets we are technically in an ice age) Which in turn was caused by the movement of continents close enough to the poles to create permanent ice caps. the freezing of organic matter into permafrost is not a fast occurrence, it is a &lt;a href=&quot;https://nsidc.org/cryosphere/frozenground/methane.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;slow build up&lt;/a&gt; of organics as soil is built and added too, as long as it remains cold enough for permafrost to persist.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The strange thing about the warming now is every major natural factor and most minor factors point towards cooling conditions yet we have warming. Human activity however is producing strong warming factors that are overriding the natural prevailing conditions, which makes you wonder what will happen when some of the natural factors stary cycling back to warming. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2019-09-12T03:34:41.027" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17969" PostTypeId="1" CreationDate="2019-09-12T08:19:30.593" Score="1" ViewCount="450" Body="&lt;p&gt;What is sub-tropical wet climate, semi-arid climate and semi-tropical continental climate?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I encountered this while reading climate of my state &lt;strong&gt;Haryana&lt;/strong&gt;.&#xA;(I have no background in environmental science)&lt;/p&gt;&#xA;" OwnerUserId="17851" LastEditorUserId="2470" LastEditDate="2020-04-04T18:04:57.057" LastActivityDate="2020-04-05T16:46:44.977" Title="What is sub-tropical wet climate, semi-arid climate and semi-tropical continental climate?" Tags="|climate|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17971" PostTypeId="2" ParentId="17969" CreationDate="2019-09-12T10:55:10.467" Score="1" Body="&lt;p&gt;The sub-tropics are climatically very variable. Most of this zone is arid or semi-arid, but there are some wet areas. The wet areas also vary considerably. Some of them have quite cold winters where the temperature just manages to keep a few degrees above zero, others keep comfortably above zero.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sub-tropical wet climates can be found at the northern extremity of the South China Sea in places like Hongkong and Hainan Island, both in southern China. Here you can find classical rainforest not much different from that which exists over most of S.E. Asia, so that would be sub-tropical wet climate.. The climate in elevated areas of tropical Africa and New Guinea also falls into some definitions of sub-tropical (definitions vary a little) and have a similar climate to S.W.China. Further away from the tropics you can still find wet areas, but as I say, the sub-tropics tend to be mostly arid or semi-arid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Continental subtropics tend to be more arid and have colder winters, while small islands in subtropical areas have a marine climate and tend to be damper and have milder winters. The Canaries are an example. North Island, New Zealand, is subtropical and has a climate similar to the better areas of the Mediterranean. The Sahara desert is mostly subtropical and very arid, but the Atlas mountains in the north are damper. Mountains tend to attract rainfall.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-12T10:55:10.467" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17973" PostTypeId="1" CreationDate="2019-09-12T14:45:12.087" Score="2" ViewCount="268" Body="&lt;p&gt;I have data from the national &lt;a href=&quot;https://www.spc.noaa.gov/wcm/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;storm prediction center&lt;/a&gt; that is marked with values of :&#xA;elat &#xA;slat&#xA;elon&#xA;slon&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;`slat        slon        elat        elon&#xA;`31.6671    -90.9352    31.6998     -90.8813&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;What do those values mean?&lt;br&gt;&#xA;What does the &quot;s&quot; &amp;amp; &quot;e&quot; prefix stand for?&lt;/p&gt;&#xA;" OwnerUserId="17852" LastActivityDate="2019-09-12T15:07:12.343" Title="What does slat and elat (slon, elon) in latitude and longitude values mean?" Tags="|models|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17974" PostTypeId="2" ParentId="17973" CreationDate="2019-09-12T15:05:49.173" Score="1" Body="&lt;p&gt;Oh, I think I finally figured out what those values are.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data is tornado data and I believe the slat, slon are &lt;strong&gt;Start&lt;/strong&gt; locations (of the tornado) and the elat, elon are &lt;strong&gt;End&lt;/strong&gt; locations for the tornado.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This only became apparent when I added those locations to a Google map and saw the distances.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a &lt;a href=&quot;https://www.google.com/maps/dir/&amp;#39;31.6671,-90.9352&amp;#39;/31.699799985277465,+-90.8813000175732/@31.6813792,-90.9501063,13z/data=!3m1!4b1!4m9!4m8!1m3!2m2!1d-90.9352!2d31.6671!1m3!2m2!1d-90.8813!2d31.6998&quot; rel=&quot;nofollow noreferrer&quot;&gt;map with the two locations&lt;/a&gt; on it (obviously the path is a driving path and not path of tornado, but it shows the distance).&lt;/p&gt;&#xA;" OwnerUserId="17852" LastActivityDate="2019-09-12T15:05:49.173" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17975" PostTypeId="2" ParentId="17973" CreationDate="2019-09-12T15:07:12.343" Score="4" Body="&lt;p&gt;This might be product specific, but if it's anything like my MODIS experience this refers to &lt;strong&gt;s&lt;/strong&gt;tart and &lt;strong&gt;e&lt;/strong&gt;nd latitude and longitude. Are you looking at a small region on the Mississippi/Louisiana border?&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2019-09-12T15:07:12.343" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17976" PostTypeId="2" ParentId="17739" CreationDate="2019-09-12T19:50:49.073" Score="1" Body="&lt;p&gt;Yes, using GMPES. E.g., you can look at the USGS &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/eventpage/ci38457511/shakemap/intensity&quot; rel=&quot;nofollow noreferrer&quot;&gt;shakemap&lt;/a&gt; which includes some measure of intensities such as PGA/PGV. Just choose an appropriate cut-off value and you have your area.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastEditorUserId="1275" LastEditDate="2019-09-12T20:25:09.183" LastActivityDate="2019-09-12T20:25:09.183" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17977" PostTypeId="2" ParentId="17606" CreationDate="2019-09-12T20:10:26.443" Score="2" Body="&lt;p&gt;It can be high but is bounded because the slip velocity on fault (as it slips during an earthquake) is usually of the order of 1-3 m/sec.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kaikoura earthquake (M7.8 strike slip event) had a max PGA of 3.1 g (second highest ever recorded) but it is attributed due to flapping effect. See &lt;a href=&quot;https://www.nature.com/articles/s41598-018-37716-y&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; for more details.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastActivityDate="2019-09-12T20:10:26.443" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17978" PostTypeId="2" ParentId="17470" CreationDate="2019-09-12T20:20:14.553" Score="1" Body="&lt;p&gt;Actually, there is a shear zone in NW Australia. The Australian plate is somewhat stuck near the Timor Trough but keeps subducting in the west near Java. This naturally cause shear stress to accumulate in NW Australia which has to be eventually released as strike slip earthquakes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tHULm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tHULm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;https://www.researchgate.net/publication/270822781_The_Western_Australia_shear_zone&quot; rel=&quot;nofollow noreferrer&quot;&gt;Whitney et al.&lt;/a&gt; for more details.&lt;/p&gt;&#xA;" OwnerUserId="1275" LastActivityDate="2019-09-12T20:20:14.553" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17980" PostTypeId="1" CreationDate="2019-09-12T21:17:40.733" Score="1" ViewCount="46" Body="&lt;p&gt;What are the properties of the back arc extension related volcanic rocks and/or related magma? (e.g. Basin and Range region)&lt;/p&gt;&#xA;" OwnerUserId="15195" LastActivityDate="2019-09-12T22:48:31.207" Title="What are the properties of the back arc extension related volcanic rocks?" Tags="|magmatism|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17981" PostTypeId="2" ParentId="17980" CreationDate="2019-09-12T22:48:31.207" Score="1" Body="&lt;p&gt;Back arc basin lavas are basaltic and similar to the magma from mid ocean ridges, except that the magma from back arc basins is about four times as rich in magmatic water, which is typically 1.5 percent by weight of the rock.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-12T22:48:31.207" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17982" PostTypeId="1" CreationDate="2019-09-12T23:49:55.167" Score="1" ViewCount="37" Body="&lt;p&gt;In all the explanations of how global electric circuit on Earth works, I've always encountered statements like &quot;thunderstorms generate ionospheric potential&quot; (which is about 250 kV). &#xA;E.g. here: &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2009JA014758&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2009JA014758&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But how is that possible? Thunderstorm (or, more specifically, a lightning strike) is inherently a &lt;em&gt;discharge&lt;/em&gt; rather than a &lt;em&gt;generator&lt;/em&gt;. It's the breakdown of an abstract capacitor rather than the charging of it. For all intents and purposes, thunderstorms should reduce any potential difference that exists around them rather than sustain it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can somebody explain, what &lt;em&gt;actually&lt;/em&gt; drives the upward current that is observed above thunderstorms? Surely it cannot be lightning itself, so what then? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(I'm perfectly aware that there is also a downward current in fair weather; but the same question remains - where is the generator that causes it?)&lt;/p&gt;&#xA;" OwnerUserId="17855" LastActivityDate="2019-09-12T23:49:55.167" Title="How do thunderstorms generate ionospheric potential?" Tags="|atmosphere|thunderstorm|electromagnetism|ionosphere|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17983" PostTypeId="1" AcceptedAnswerId="17984" CreationDate="2019-09-13T08:59:29.937" Score="3" ViewCount="96" Body="&lt;p&gt;I am a student and I have a very simple and yet important question about reanalysis data. Recently, I attended a workshop where various other students discussing the use of ERA5 reanalysis data on their research and at some point, there was the question : &quot;&lt;strong&gt;what does the use of reanalysis data means for your research and how this type of data can impact your results?&lt;/strong&gt;&quot; Nobody had a satisfying answer and now, I am trying to find papers discussing this issue. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, can someone use ERA5 parameters on a random forest model as explanatory variables and if so, what does it means for the results?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apologies if it is a very basic question, I am new in this area. &lt;/p&gt;&#xA;" OwnerUserId="11409" LastActivityDate="2019-09-13T14:06:55.767" Title="How reanalysis data influence our research/results?" Tags="|models|reanalysis|impacts|research|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17984" PostTypeId="2" ParentId="17983" CreationDate="2019-09-13T14:06:55.767" Score="3" Body="&lt;p&gt;Welcome to StackExchange SE! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't think I fully understand your question, but I'll try to answer it. Reanalysis data is the use of weather models and data assimilation to piece back the weather. It is a 4-dimensional dataset (Latitude, longitude, pressure levels, and time). You can do whatever you wish with that data (provided you follow the legal guidelines with using the ERA dataset), but know that it isn't perfect; it usually is at a coarse resolution, and doesn't always contain everything you may want. Often reanalysis data can be used as input into other meteorological models, such as the &lt;a href=&quot;https://github.com/wrf-model/WRF&quot; rel=&quot;nofollow noreferrer&quot;&gt;WRF model&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as a random forest model, it really depends on what your intentions and design are. Admittedly, I don't know much about random forest model or your experimental design. To answer the question of whether the data could be used as explanatory variables, sure if you have some data that isn't within the dataset. But be aware of the limitations. There are other highly used reanalysis datasets, such as the &lt;a href=&quot;https://climatedataguide.ucar.edu/climate-data/climate-forecast-system-reanalysis-cfsr&quot; rel=&quot;nofollow noreferrer&quot;&gt;CFSR&lt;/a&gt; and &lt;a href=&quot;https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/&quot; rel=&quot;nofollow noreferrer&quot;&gt;MERRA-2&lt;/a&gt; and &lt;a href=&quot;https://www.esrl.noaa.gov/psd/data/gridded/reanalysis/&quot; rel=&quot;nofollow noreferrer&quot;&gt;a variety of other reanalysis datasets&lt;/a&gt;, but those have similar limitations too.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2019-09-13T14:06:55.767" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17985" PostTypeId="1" CreationDate="2019-09-13T22:51:51.413" Score="-2" ViewCount="957" Body="&lt;p&gt;Dr. Robert Holmes has converted the ideal gas law to T = P M / (ρ R) in this paper: (&lt;a href=&quot;http://article.sciencepublishinggroup.com/pdf/10.11648.j.earth.20170606.18.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Molar Mass Version of the Ideal Gas Law Points to a Very Low Climate Sensitivity&lt;/a&gt;) with T = temperature P = near-surface pressure R = gas constant ρ = near-surface density M = near-surface atmospheric mean molar mass.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems to work on a planet that has an atmosphere  &gt; 10 kPa to accurately determine its surface temperature regardless of the atmosphere's composition. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If planetary surface temperature can be determined by pressure, density and mean moles, what does this say to the IPCC claim that temperature will raise by up 5 deg C with a doubling of CO2.  &lt;/p&gt;&#xA;" OwnerUserId="17846" LastEditorUserId="5282" LastEditDate="2019-09-14T03:29:35.720" LastActivityDate="2019-09-15T00:07:53.007" Title="Could someone please validate the Holmes equation" Tags="|climate-change|temperature|climate-models|earth-system|pressure|" AnswerCount="1" CommentCount="7" ClosedDate="2019-09-16T12:36:34.747" ContentLicense="CC BY-SA 4.0" />
  <row Id="17986" PostTypeId="1" CreationDate="2019-09-13T23:09:55.627" Score="1" ViewCount="13" Body="&lt;p&gt;Are there any statistical/numerical models developed relating release from reservoirs with the downstream river temperatures? I know of complicated hydrodynamic models such as CE-QUAL-W2 etc. but I am trying to know if someone has worked on specifically modeling the temperature with reservoir operations, in case such a relation exists.&lt;/p&gt;&#xA;" OwnerUserId="14450" LastActivityDate="2019-09-13T23:09:55.627" Title="Model relating reservoir releases with downstream temperature" Tags="|temperature|numerical-modelling|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17988" PostTypeId="2" ParentId="17985" CreationDate="2019-09-14T09:48:51.557" Score="2" Body="&lt;p&gt;There is no such thing as the 'Holmes' equation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Comment: Holmes is the person that formulated this equation I has every right to name it as I please.&#xA;Could someone please validate the Holmes equation&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is no such thing as the 'Holmes' equation. To the ideal gas law&#xA;&lt;span class=&quot;math-container&quot;&gt;$$T=\frac{P\mu}{R\rho}$$&lt;/span&gt;&#xA;if P, ρ and μ&lt;/p&gt;&#xA;&#xA;&lt;p&gt;are known in order to 'predict' a temperature is&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Trivial&lt;/li&gt;&#xA;&lt;li&gt;Not a predicition, but a statement of state variables.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The ideal gas law, is an Equation of State, not a predictive equation (I don't see any ∂T/∂t in it). As such, it connects the quantities in it at any given point in time, but it cannot be used to compute a time-evolution. Therefore, that Holmes can 'predict' the correct surface temperatures, given the input data P, ρ and μ is a no-brainer in any sufficiently dense gas.&lt;br&gt;&#xA;It's actually embarassing for the journal that would publish this. It's either intentionally misleading (climate change denier journal) or they're just garbage scientists. The science involved in predicting where temperatures will evolve is more difficult than stating an equation of state, and at an absolute minimum requires solving evolution equations for P and ρ.&lt;br&gt;&#xA;Any evolution for P or T will necessarily be coupled to the radiative balance of the atmosphere, which is what the whole Greenhouse issue is about, and what has been completely ignored by this publication.&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="489" LastEditDate="2019-09-15T00:07:53.007" LastActivityDate="2019-09-15T00:07:53.007" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17990" PostTypeId="1" CreationDate="2019-09-15T00:24:21.383" Score="2" ViewCount="1083" Body="&lt;p&gt;I've read answers that outline how if we afforested large (continental-scale) masses of land, it would do little in the way of tackling climate change. While it would sequester &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; for about a century after it was planted (while growing) before reaching equilibrium, the planting of large quantities of trees would also sufficiently decrease the albedo of the land in which it was planted, that it would hold in a lot more heat than the land it replaced (likely desert or otherwise barren land). This means that, all things considered, it would make a negligible, if not negative impact, in tackling global warming. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this is the case, why do we associate &quot;planting trees&quot; as a good thing, on the scale of individuals planting individual trees? Is it because generally, these trees improve ecosystem vitality/diversity, or for some similar reason unrelated to climate? &lt;/p&gt;&#xA;" OwnerUserId="17869" LastEditorUserId="2470" LastEditDate="2020-01-05T19:24:23.917" LastActivityDate="2022-07-25T15:34:59.377" Title="If planting trees is ineffective to tackle climate change, why do people plant them?" Tags="|climate-change|carbon-cycle|" AnswerCount="7" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="17991" PostTypeId="1" AcceptedAnswerId="18023" CreationDate="2019-09-15T04:51:02.507" Score="2" ViewCount="244" Body="&lt;p&gt;Something I hear often from climate scientists, and indeed even politicians, is that we &quot;don't understand climate change very well&quot;. And, I'm sure this is true since the climate is a complex adaptive system with thousands of dependent variables, one that we don't yet have the computational sophistication to accurately model. But that doesn't mean we don't know, to a high degree of accuracy, what is going to happen if we make certain changes to the atmospheric composition or take certain actions. We have paleoclimate data ranging extensively far back many hundreds of thousands of years, encompassing global temperature, climate cycling, atmospheric composition, and more. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sure, the global temperature 100,000 years ago wasn't measured using a thermometer, but we've used various independent proxy methods that all agree with each other to a reasonable degree, right? And so do we not then have a reasonably accurate idea of Earth's climate sensitivity by simply looking at precedent? And paleoclimate will be close to &lt;em&gt;exactly&lt;/em&gt; right since it takes all the variables into account &lt;em&gt;exactly&lt;/em&gt; in the amount they're needed to be accounted for. Why are we still &quot;uncertain&quot; about the realities of climate change? Why are we not moving on and taking decisive action based on this--what seems to me--reliable, accurate data?&lt;/p&gt;&#xA;" OwnerUserId="17869" LastActivityDate="2019-10-18T18:00:06.907" Title="Why rely on climate models as opposed to paleoclimate data?" Tags="|climate-change|models|climate-models|paleoclimatology|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17992" PostTypeId="2" ParentId="17990" CreationDate="2019-09-15T07:37:22.383" Score="-1" Body="&lt;p&gt;Planting trees is a good thing provided it is done properly. In Britain we have some valuable habitats such as heathland, peatbog, and wetland where planting trees would do ecological damage. If for example you managed to put a small stand of trees in an area of wetland, that would encourage hawks and corvids to take up residence to the disadvantage of wetland wildlife, and it's the same with heathland and peatbog. I doubt if it is possible to plant enough trees to make a major impact on the CO2 problem, but they will make some difference if only a small one, and in the right place can be a wildlife asset as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It would be impossible to grow trees in most true deserts, but in the Namib and Atacama there are places where sea mists roll in from the sea and condense on any object which protrudes from the sand. Maybe it's possible there. The most promising place for tree planting is in restoring the S.American rainforest, where there could be a huge environmental benefit. It could be financed with foreign aid money which wold go direct to impoverished rural communities, thus killing several birds with one stone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a scheme underway in Britain to encourage the spread of sea grass meadows, which are important to the marine environment and apparently are more efficient at sequestering carbon than most things you can grow on land. Again the contribution will be small, but better than nothing. Sea grass is a true grass, but somehow manages to grow completely submerged in shallow salt water. Few people are aware of its existence. Restoring mangroves, which are basically small trees able to grow in tropical estuarine waters, is another area of environmental improvement which would also assist in the battle against CO2.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-15T07:37:22.383" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="17993" PostTypeId="2" ParentId="17991" CreationDate="2019-09-15T09:41:05.380" Score="-3" Body="&lt;p&gt;It is true that we don't understand climate change very well for the reasons you give in your question, namely that there are so many variables involved and some of them are unknowns. Indirect methods of assessing climate composition and temperature are reasonably accurate for the last few tens of thousands of years, but the further you go back, the more scope there is for error to creep in. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Computers are helpful, but not the be-all and end-all. Garbage in, garbage out, as the old saying goes. There comes a point in the prehistorical climate record where palaeontology is the best guide to what ancient climates were like. Paleoclimatic data can't be exactly right when you get to this point because it is too far back, and although palaeontology can tell you what sort of climate we had millions of years ago, it can't explain what part CO2 abundance played.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Changing the composition of the atmosphere is more difficult than some people imagine. Oxygen and nitrogen are present in countless trillions of tons, and the oxygen is constantly being replenished by photosynthesis. Most photosynthesis takes place in the oceans. This same photosynthesis is also removing CO2 from the atmosphere. Because CO2 is only present in trace amounts, it is the only atmospheric constituent we can do anything about, with the possible exception of methane. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fact that plants grow more vigorously in an atmosphere where CO2 content is enhanced adds another complication. There is no serious doubt that atmospheric CO2 has increased since the industrial revolution got well underway, that climate change is real, and that we are currently in a warming phase, but whether CO2 is the sole cause of it is another thing. Action is being taken to reduce CO2 in the atmosphere, but not enough to make a measurable difference. The reason much sterner measures will not be taken is that the major industrial countries which are the main emitters are worried about the damage to their industries and economies if they do everything that environmentalists want.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-15T09:41:05.380" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17995" PostTypeId="1" CreationDate="2019-09-15T13:12:24.680" Score="4" ViewCount="121" Body="&lt;p&gt;The &lt;a href=&quot;https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.2153-3490.1964.tb00181.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dansgaard paper&lt;/a&gt; I've seen shows a roughly linear relationship between the delta-O18 in precipitation and mean annual temperature (at a given location). See Figure 3 in the paper.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When converting delta-O18 into a corresponding delta-temperature, is this simple linear relationship assumed? Or is it more complex than that? What caveats or assumptions go into such a conversion?&lt;/p&gt;&#xA;" OwnerUserId="669" LastEditorUserId="26841" LastEditDate="2024-03-10T10:05:41.673" LastActivityDate="2024-03-10T10:05:41.673" Title="Ice cores: how is Oxygen-18 isotopic variation converted to temperature changes?" Tags="|ice-sheets|isotopic|paleoclimate|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="17996" PostTypeId="1" CreationDate="2019-09-15T14:26:06.403" Score="3" ViewCount="350" Body="&lt;p&gt;Here question ends. Beyond details exist&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do they occur on the same tectonic regime?&#xA;For a start to distinguish Subalkali rocks froms Alkali rocks, &#xA;my knowledge says that mantle is the source of Alkali rocks. Ocean Island Basalts are Hawaii, Reunion etc are all Alkali rocks. Large ignous provinces are also sourced from mantle by the mantle plumes. Such as Deccan, Siberian traps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But in Robil Gill's ((Gill, R. (2010). Igneous rocks and processes: a practical guide. John Wiley &amp;amp; Sons.)) book on page 291, (chapter 9-Alkali rocks) says that Most of the large igneous provinces are subalkaline and they are much bigger and more frequent than the Alkaline Large igneous province. From this i derive that LIP's can be subalkaline. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So are there any difference between subalkali and alkali rock occuring tectonic environments ?&lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="15195" LastEditDate="2019-09-15T19:38:16.487" LastActivityDate="2019-09-17T12:22:06.377" Title="Are there any differences between the subalkali and alkali rock occuring tectonic environments?" Tags="|petrology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="17997" PostTypeId="1" AcceptedAnswerId="17999" CreationDate="2019-09-15T19:33:29.750" Score="3" ViewCount="2701" Body="&lt;p&gt;So I heard that the Ozone Layer is a layer of gas in Earth's atmosphere. And I also heard once that the Ozone Layer is crucial in protecting life on Earth, as it blocks out harmful rays emitted by the Sun. But over the years, the Ozone layer is slowly degrading due to the constant emission of chemicals. That's straight forward stuff...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I once heard that super sonic jets can also contribute to the degradation of the Ozone Layer. What!? I didn't know jets could do that! This is what I would like to know:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Is this claim true?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;And if it is, how high up and fast do the jets have to be?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Also, how is this even possible?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Does the jet create strong winds to blow the Ozone Layer away or something? Any feedback would be highly appreciated, thanks!&lt;/p&gt;&#xA;" OwnerDisplayName="user17688" LastActivityDate="2022-02-16T00:13:54.933" Title="Can planes damage the ozone layer?" Tags="|ozone|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="17998" PostTypeId="1" AcceptedAnswerId="18052" CreationDate="2019-09-15T19:56:04.053" Score="1" ViewCount="999" Body="&lt;p&gt;For TAS diagram plot, one need to recalculate Major oxide data (NaO, K2O, SiO2).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do one need to recalculate the ppms of Zr,Nb and Y and % of TiO2 for Zr/TiO2 vs Nb/Y diagram plotting for rock classification?&lt;/p&gt;&#xA;" OwnerUserId="15195" LastActivityDate="2019-11-27T08:03:42.073" Title="XRF analysis - recalculating results" Tags="|geochemistry|petrology|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="17999" PostTypeId="2" ParentId="17997" CreationDate="2019-09-15T20:53:25.353" Score="0" Body="&lt;p&gt;Yes, high flying jets can damage the ozone layer, but the consensus of opinion is that at present this damage is trivial and nothing to worry about. If, on the other hand, Concorde-type supersonic transports were to become commonplace, it might be another matter. It was found that Concorde's engines produced much more sulphuric acid particles than the exhausts of subsonic aircraft, and it was this sulphuric acid that damaged the ozone layer. Whether or not enough supersonic military aircraft fly at the relevant altitude and cause significant damage is something nobody seems to know, but probably not. The jets need to fly at altitudes between about 30,000 feet and 45,000 feet to cause ozone damage.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-15T20:53:25.353" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18000" PostTypeId="1" AcceptedAnswerId="18001" CreationDate="2019-09-15T22:03:32.587" Score="2" ViewCount="85" Body="&lt;p&gt;I have a question about the seas and ocean we swim in. How does the Ocean get rid off all the natural pollutants (for example dead animal debris) and man-made pollutants (human waste, garbage, etc)? I know that there's salt in the water, which helps to kill bacteria, but does salt really do that much? And also, I heard that the Ocean is so big, that pollutants are naturally diluted through the waters, making it safe. Is this true?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oh, and I don't mean those giant plastic garbage deposits out in the middle of the ocean, I'm talking about our beaches and seas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm asking this because I never see any brownish murky water whenever I go swimming. Any feedback would be highly appreciated. Thanks!&lt;/p&gt;&#xA;" OwnerDisplayName="user17688" LastActivityDate="2019-09-15T23:47:04.877" Title="How does nature dilute Ocean and Seas so that we can swim in them?" Tags="|oceanography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18001" PostTypeId="2" ParentId="18000" CreationDate="2019-09-15T23:47:04.877" Score="0" Body="&lt;p&gt;You hit on the main reason why sea water is fairly clean, which is the fact that the sea is so vast. Salt water kills some micro-organisms, but by no means all. The sea is teeming with countless trillions of them, some dangerous but most not. The sea is full of hungry animals which feed on animal detritus. Some of these animals are small, like anemones and corals, and some are large, mostly species of fish and hagfish. Some dead vertebrates like whales sink down into the abyssal ocean depths, where they provide a feast for various deep sea creatures. This has been going on for many millions of years, and many a dinosaur has been eaten and dissolved away by creatures beneath the waves. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The many plants (sea grass and mangroves etc) and algae (seaweeds) also require nourishment, some of which comes from non-biological sources, and some from the excreta and decaying bodies of birds and other animals. Plastic is washed ashore and broken down into smaller and smaller fragments. Some beaches around the word are sufficiently polluted that they are classed as dangerous, and unfit to swim in, but may nevertheless seem to be clean. A few such beaches are in UK, so there must be some in America as well.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-15T23:47:04.877" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18003" PostTypeId="1" CreationDate="2019-09-16T07:27:08.823" Score="1" ViewCount="1045" Body="&lt;p&gt;I have the following equation for the shearing term of the deformation zone in meteorology. The reference is &lt;a href=&quot;http://www.zamg.ac.at/docu/Manual/SatManu/main.htm?/docu/Manual/SatManu/CMs/Def/backgr.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Shearing = &lt;span class=&quot;math-container&quot;&gt;$\frac{dV}{dx} + \frac{dU}{dy}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;${U}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;${V}$&lt;/span&gt; are the zonal and meridional winds, respectively; &lt;span class=&quot;math-container&quot;&gt;${x}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;${y}$&lt;/span&gt; are the longitude and latitude, respectively.&lt;/p&gt;&#xA;&lt;p&gt;I would like to know what does it mean to have if:&lt;/p&gt;&#xA;&lt;p&gt;a) &lt;span class=&quot;math-container&quot;&gt;$\frac{dV}{dx}$&lt;/span&gt; &amp;lt; 0 and &lt;span class=&quot;math-container&quot;&gt;$\frac{dU}{dy}$&lt;/span&gt; &amp;gt; 0;&lt;/p&gt;&#xA;&lt;p&gt;b) &lt;span class=&quot;math-container&quot;&gt;$\frac{dU}{dy}$&lt;/span&gt; &amp;lt; 0 and &lt;span class=&quot;math-container&quot;&gt;$\frac{dV}{dx}$&lt;/span&gt; &amp;gt; 0;&lt;/p&gt;&#xA;&lt;p&gt;c) both &lt;span class=&quot;math-container&quot;&gt;$\frac{dV}{dy}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\frac{dU}{dx}$&lt;/span&gt; are less than 0;&lt;/p&gt;&#xA;&lt;p&gt;d) both &lt;span class=&quot;math-container&quot;&gt;$\frac{dV}{dy}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\frac{dV}{dx}$&lt;/span&gt; are greater than 0.&lt;/p&gt;&#xA;" OwnerUserId="16927" LastEditorUserId="-1" LastEditDate="2021-09-18T17:31:55.320" LastActivityDate="2021-09-18T17:31:55.320" Title="Question about the sign of the shearing deformation terms" Tags="|meteorology|wind|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18006" PostTypeId="2" ParentId="17996" CreationDate="2019-09-16T20:00:18.183" Score="-1" Body="&lt;p&gt;I can't put it as a comment so it'll have to be an answer this time around.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Either way, I remember doing chemical analysis and my professor at the time was very adamant that yes, there is a difference depending on tectonic setting. Alkaline magma series tend to be present in convergent configurations, however, it's not exclusively found in these. To be honest, the question is a bit too broad to be summed up here but use it as a rule of thumb, according to my professor. However, subalkaline series are present in most plate settings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a lot of interaction going on with magma from the mantle reservoir during its ascent through the crust which could be a source of contamination after all. &lt;/p&gt;&#xA;" OwnerUserId="17806" LastActivityDate="2019-09-16T20:00:18.183" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18009" PostTypeId="2" ParentId="17996" CreationDate="2019-09-17T12:22:06.377" Score="3" Body="&lt;p&gt;Yes, there are many differences and subdifferences and nuances.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will try to keep it in simple terms which will satisfy your question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Alkaline magmas&lt;/strong&gt; form by low degree partial melting of the deep mantle. This is why you see them in hotspots. It's very hot down there, but you do not form a lot of melt. For example, the amounts of melts in Hawaii are negligible compared to what you have in large igneous provinces (think Deccan Traps) or mid ocean ridges. Another tectonic setting with common alkaline magmas are rift zones. The best example is the east African Rift (Ethiopia, Kenya, etc). Again - deep melting of the mantle leads to alkaline magmatism.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Subalkaline magmas&lt;/strong&gt; form in shallower melting. For example, the voluminous mid ocean ridge basalts are not alkaline, and the melt forms within a few kilometres of the surface. Arc magmas (andesites etc) are also not too alkaline because they form by fluid-assisted melting of not too deep mantle above subduction zones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even though large igneous provinces form by mantle plumes, the melting so extensive that the melts are not alkaline any more. To get alkaline melts, it has to be low-degree partial melt.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-09-17T12:22:06.377" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18011" PostTypeId="1" CreationDate="2019-09-17T17:58:58.010" Score="1" ViewCount="34" Body="&lt;p&gt;I know I can google each data point (latitude, longitude, date) one by one and find if the government of that country has archived past weather information. But this will take infinite amount of time for large datasets in a wide range of date and location worldwide. Is there any way to get around this? Thank you so much.&lt;/p&gt;&#xA;" OwnerUserId="3241" LastActivityDate="2019-09-17T17:58:58.010" Title="Is there any program that gives you air temperature (and precipitation) information if you feed them the date and location (latitude,longitude)?" Tags="|meteorology|software|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18013" PostTypeId="1" CreationDate="2019-09-17T19:07:32.293" Score="5" ViewCount="750" Body="&lt;p&gt;Every volcano is a mountain, but not every mountain is a volcano. Still, it strikes me that--at least for the mountain ranges I can think of in this moment--they all seem to have igneous cores. Is this generally true, or are there plenty of examples of mountain ranges with sedimentary or metamorphic cores?&lt;/p&gt;&#xA;" OwnerUserId="54" LastActivityDate="2019-12-08T20:29:30.790" Title="Are the cores of every mountain range igneous?" Tags="|volcanology|mountains|igneous|orogeny|" AnswerCount="4" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18014" PostTypeId="2" ParentId="18013" CreationDate="2019-09-17T20:28:36.813" Score="9" Body="&lt;p&gt;Many mountain ranges do not have igneous cores. The front ranges of the Rocky Mountains in British Columbia are created by &lt;a href=&quot;https://en.wikipedia.org/wiki/Thrust_fault&quot; rel=&quot;noreferrer&quot;&gt;thrust faults&lt;/a&gt; that push sedimentary strata up to form the mountains. The driving force for this motion is a subduction zone located 100's of kilometres to the west. I believe that the Himalayas mountains are formed in a similar fashion.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;See the following Wikipedia article: &lt;a href=&quot;https://en.wikipedia.org/wiki/Geology_of_the_Rocky_Mountains&quot; rel=&quot;noreferrer&quot;&gt;Geology of the Rocky Mountains&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastEditorUserId="17535" LastEditDate="2019-09-18T09:50:42.917" LastActivityDate="2019-09-18T09:50:42.917" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18020" PostTypeId="1" CreationDate="2019-09-18T08:08:53.130" Score="1" ViewCount="817" Body="&lt;p&gt;What determines the direction that a wind blows?&#xA;I understand that the nature of my question is immensely broad but I see no other way to phrase the question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question surfaced in my mind when I was checking out the windmap for the South East Asian region as I was monitoring the haze conditions there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/N8eyF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/N8eyF.png&quot; alt=&quot;snapshot 1602 GMT+8, 18 Sept 2019&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;snapshot 1602 GMT+8, 18 Sept 2019&lt;/p&gt;&#xA;&#xA;&lt;p&gt;moved my extra thoughts to comments so I don't bog down the actual description&lt;/p&gt;&#xA;" OwnerUserId="17888" LastActivityDate="2019-09-19T06:25:50.557" Title="What determines the direction of wind" Tags="|meteorology|wind|" AnswerCount="2" CommentCount="3" ClosedDate="2019-09-18T14:38:55.303" ContentLicense="CC BY-SA 4.0" />
  <row Id="18021" PostTypeId="2" ParentId="18020" CreationDate="2019-09-18T14:13:28.097" Score="-2" Body="&lt;p&gt;Most places have a prevailing wind, which is the main direction the wind comes from. In UK the prevailing wind is from the south west, which moving across the Gulf Stream gives us a mild, damp, marine climate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Winds usually come in a rotating swirl which you can often see in satellite photos. It's a swirling air mass like a hurricane, but usually far less violent, and in a low pressure system north of the Equator the air moves counter-clockwise. Meteorologists call this a cyclone. If you can visualise one of these swirling air masses moving across UK or Malaysia, the leading edge of this rotating air mass might be blowing from south-east toward the north when it first touches land, but soon after, the trailing edge will pass over the same land, and then the wind will blow in the opposite direction. A high pressure system is called an anti-cyclone, and the wind from an anti-cyclone circulates clockwise in the northern hemisphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The speed with which it changes direction depends on several things, but mainly the size or diameter of the rotating air mass. There is this tendency for these rotating air masses to drift from  west to east. Winds are always strongest where there is low pressure and tend to be much calmer in high pressure.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="2470" LastEditDate="2019-09-19T06:25:50.557" LastActivityDate="2019-09-19T06:25:50.557" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18022" PostTypeId="2" ParentId="18020" CreationDate="2019-09-18T14:22:21.353" Score="4" Body="&lt;h2&gt;Sunlight (heat), planetary rotation, and the shape of the land in passes over.&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Prevailing wind is mostly caused by hadley cells, or the masses of air move due to the thermal difference between the pole and the equator as well as the surface of the earth and space. Thus it is the interaction of two different thermal convection cells. this moment twists into cells due the coriolis effect and the earths rotation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.weather.gov/source/zhu/ZHU_Training_Page/winds/Wx_Terms/Flight_Environment.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;these cells can be somethat disrupted on the local level by things like mountains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Q1y27.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Q1y27.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2019-09-18T14:22:21.353" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18023" PostTypeId="2" ParentId="17991" CreationDate="2019-09-18T17:03:39.457" Score="3" Body="&lt;p&gt;We need both paleodata &lt;em&gt;and&lt;/em&gt; models, in fact the relationship between paleodata and the climate at a certain time is typically evaluated through models. Paleodata does not actually measure climate observables directly (tempreture/pressure/salinity/other) but instead is (e.g.) a geochemical quantity related to one of those. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, the two most frequently used records are the Antarctica EPICA ice core record and the Lisiecki Raymo benthic stack. The isotopes in these records are affected by temperature at a point on the planet and global ice volume, but how that relates to global temperature and the size of individual ice sheets requires inference from climate models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further, climate (or earth systems) models can allow us to probe what could happen in addition to what did happen. Current CO2 levels are reaching a point not seen in the ice core record (our most direct records) and so we need increasingly complex models to get a handle on the range of possibilities.&lt;/p&gt;&#xA;" OwnerUserId="17094" LastActivityDate="2019-09-18T17:03:39.457" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18028" PostTypeId="1" AcceptedAnswerId="18038" CreationDate="2019-09-19T19:18:52.083" Score="5" ViewCount="369" Body="&lt;p&gt;With Earth getting hotter and hurricanes also getting larger I wonder; Is there a limit on how big a hurricane can physically get? &lt;/p&gt;&#xA;" OwnerUserId="17898" LastEditorUserId="39" LastEditDate="2019-09-19T23:38:08.440" LastActivityDate="2019-09-22T04:12:47.140" Title="What is the largest hurricane possible?" Tags="|meteorology|geophysics|tropical-cyclone|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18029" PostTypeId="2" ParentId="17920" CreationDate="2019-09-19T20:35:38.973" Score="0" Body="&lt;p&gt;After several days i made a new explanation beyond fissure and laccolith. For refreshing 1-) I have observed the disturbed marl layers 2-) i also saw flowing structures (froth etc.). The problem is how can that these two phenomenon meet for solution. There is one another option to talk about. Exogenus domes, which can bend surrounding layers and able flow (when reaching enough slope angle)&lt;/p&gt;&#xA;" OwnerUserId="15195" LastActivityDate="2019-09-19T20:35:38.973" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18030" PostTypeId="1" AcceptedAnswerId="18032" CreationDate="2019-09-19T20:44:34.073" Score="2" ViewCount="183" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6lkiw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6lkiw.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;In a volcanic region, i have examined two samples petrographically. One of them has biotites with extensive opacitic rims. The other samples biotites hasn't got this property. They have the same modal mineral contents. What makes the difference? &lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="725" LastEditDate="2019-09-20T07:04:10.713" LastActivityDate="2019-09-20T07:04:10.713" Title="What do opaque rims on biotite in a volcanic rock mean?" Tags="|petrography|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18031" PostTypeId="2" ParentId="2992" CreationDate="2019-09-20T03:12:50.377" Score="0" Body="&lt;p&gt;Water gradient when it is fresh water is 0.43 psi/ft.  Water's density when free of dissolved solids is 1 g/cc.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Knowing this just take your average overburden density and multiply it by the hydrostatic gradient.  So you asked how to get 1 psi ft you can back into the answer by literally dividing 1 psi/ft by  0.43 psi/ft which gives you 2.33 g/cc as the average bulk density of the overburden rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2.33 g/cc)/(1 g/cc) * 0.43 psi/ft = 1 psi/ft&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Units cancel above and you are left with the answer you are looking for psi/ft.  &lt;/p&gt;&#xA;" OwnerUserId="17900" LastActivityDate="2019-09-20T03:12:50.377" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18032" PostTypeId="2" ParentId="18030" CreationDate="2019-09-20T07:03:34.800" Score="1" Body="&lt;p&gt;There are several options.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;During decompression, biotite is no longer stable and the hydrogen volatilises, leaving behind fine-grained intergrowth of oxide and silicate minerals.&lt;/li&gt;&#xA;&lt;li&gt;Oxidation of the rims during exposure of the lava to the atmosphere. Higher Fe&lt;sup&gt;3+&lt;/sup&gt; contents would make the biotite darker.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;It is impossible to tell without a detailed electron microscopy analysis. However, my guess it that it is option 1.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-09-20T07:03:34.800" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18033" PostTypeId="2" ParentId="18013" CreationDate="2019-09-20T07:07:08.710" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;examples of mountain ranges with sedimentary or metamorphic cores&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;h1&gt;Mount Everest.&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;At an elevation of 7000 metres and higher, it is all sedimentary rock. Below 7000 metres, it is metamorphic of sedimentary protolith. There are some igneous intrusions into it, but the bulk is a metamorphic schist.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Everest#Geology&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Mount_Everest#Geology&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-09-20T07:07:08.710" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18034" PostTypeId="1" CreationDate="2019-09-20T07:23:17.753" Score="1" ViewCount="32" Body="&lt;p&gt;What is the significance of shoshonites? Why in some convergent margins, do shoshonites occur instead of andesites?&lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="2470" LastEditDate="2019-09-20T13:01:31.457" LastActivityDate="2019-09-20T13:01:31.457" Title="What are Shoshonites? What conditions make them occur instead of andesites?" Tags="|petrology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18035" PostTypeId="1" AcceptedAnswerId="18057" CreationDate="2019-09-20T09:48:48.167" Score="7" ViewCount="91" Body="&lt;p&gt;We encounter dacitic/rhyolitic melts generally in explosive volcanic events. But some of them behave as effusive dome flow. Why do some silicic bodies behave effusively?&lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="2470" LastEditDate="2019-09-20T12:59:41.943" LastActivityDate="2020-01-15T10:15:25.617" Title="Why do (some) silicic bodies behave effusively instead behaving explosively as in common?" Tags="|volcanology|magmatism|" AnswerCount="2" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18036" PostTypeId="1" CreationDate="2019-09-20T10:09:08.130" Score="1" ViewCount="22" Body="&lt;p&gt;Attached is an image of the Avra valley in Southern Arizona, USA from&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/WR018i004p01215&quot; rel=&quot;nofollow noreferrer&quot;&gt;Effects of Kriging and Inverse Modelling on Conditional Simulation of the Avra Valley Aquifier in Southern Arizona -- Clifton and Neuman&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Two related questions&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;What is this &lt;code&gt;R{int}E-T{int}S&lt;/code&gt; coordinate system? Is it US specific? Arizona specific? A reference and how to convert to a global system would be great.&lt;/li&gt;&#xA;&lt;li&gt;Is there somewhere where I can find a shape file for the designated region? I'm assuming this particular example has been used in several studies.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/l8RoF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/l8RoF.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17901" LastActivityDate="2019-09-20T10:09:08.130" Title="Avra valley aquifier region boundary" Tags="|hydrology|reference-request|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18038" PostTypeId="2" ParentId="18028" CreationDate="2019-09-20T17:04:25.980" Score="5" Body="&lt;p&gt;I am going to take an educated guess here because it is not possible(AFAIK) to accurately predict with any known skill what several decades into the future would be like.&lt;/p&gt;&#xA;&lt;p&gt;Given that premise the largest hurricane in the future could be the size of the tropical extent of the Pacific Ocean or the Atlantic Ocean(wherever that begins and ends). Here I am only considering the Northern(or Southern) tropical extent of the Pacific or Atlantic Ocean because as we know a tropical cyclone cannot cross the equator as explained in this in depth answer &lt;a href=&quot;https://earthscience.stackexchange.com/questions/239/impossible-or-improbable-hurricane-crossing-the-equator?rq=1&quot;&gt;Impossible or improbable? Hurricane crossing the equator&lt;/a&gt;. The thought process behind this idea is that hurricanes(tropical cyclones) dissipate on coming contact with land. Hence the maximum area of the largest cyclone in the future would  have to be the ocean body maximum tropical extent(typically sea surface temperature (SST) greater than 27 degrees centigrade). Just in case if people are wondering why just the tropical extent and why not more than that ? It is because once you enter into mid latitude regions frontal processes could kick in(cold core cyclones-as an example -&lt;a href=&quot;https://earthscience.stackexchange.com/questions/17832/is-it-normal-for-a-cyclonic-storm-to-form-at-the-latitude-of-new-york-usa&quot;&gt;Can a tropical cyclone form in mid latitude oceanic waters?&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;So if the tropical extent of the biggest oceans increases in the future one can imagine a very large possibly synoptic scale tropical cyclone.&lt;/p&gt;&#xA;&lt;p&gt;Here I am excluding the North Indian Ocean basin because it does not have the surface area to compete with the North Pacific or North Atlantic&lt;/p&gt;&#xA;&lt;p&gt;Secondly from this popular science article -&lt;a href=&quot;https://www.livescience.com/32179-how-strong-can-a-hurricane-get.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;How strong can a Hurricane get?&lt;/a&gt; and this one &lt;a href=&quot;https://www.livescience.com/15701-category-6-hurricanes-intensity.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Are Category 6 Hurricanes coming soon ?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;By the end of the 21st century, human-caused global warming will likely increase hurricane intensity, on average, by 2 to 11 percent, according to a review by NOAA's Geophysical Fluid Dynamics Laboratory, revised on Aug. 30, 2017.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;followed by&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;But physics dictates there must be a limit. Based on ocean and atmospheric conditions on Earth nowadays, the estimated maximum potential for hurricanes is about 190 mph (305 km/h), according to a 1998 calculation by Kerry Emanuel, a climatologist at the Massachusetts Institute of Technology.&lt;/p&gt;&#xA;&lt;p&gt;This upper limit is not absolute, however. It can change due to changes in climate. Scientists predict that as global warming continues, the maximum potential hurricane intensity will go up. They disagree, however, on what the increase will be.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So theoretically a Category 6 Hurricane could have speeds of more than 200 mph.But scientists disagree on these calculations and i am going to leave it at that.&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-09-22T04:12:47.140" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18043" PostTypeId="1" CreationDate="2019-09-21T11:06:07.897" Score="1" ViewCount="18" Body="&lt;p&gt;Is subsidence (graben faulting) expected before/during a volcanic exogenous dome emplacement on the surrounding strata?&lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="6467" LastEditDate="2019-09-21T15:42:51.287" LastActivityDate="2019-09-21T15:42:51.287" Title="Do overlying strata subside before/during volcanic exogenous dome emplacement?" Tags="|volcanology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18046" PostTypeId="1" AcceptedAnswerId="18068" CreationDate="2019-09-22T00:28:00.593" Score="2" ViewCount="479" Body="&lt;p&gt;This website&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate change global temperature&lt;/a&gt; from a governmental organization,&#xA;shows 2 graphs , one called &quot;History of global surface temperature since 1880&quot; and the other called &quot;Yearly surface temperature compared to average (1850-2018)&quot; which seems to show global temperature dropped the last 2 years. The second graph shows as source NOAA, NASA, University of East Anglia and the Japan Meteorological Agency. The lines of all of them are going down for the last 2 years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But for NASA in particular, you have in their official website  &lt;a href=&quot;https://climate.nasa.gov/vital-signs/global-temperature/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global temperature&lt;/a&gt; a graph called &quot;GLOBAL LAND-OCEAN TEMPERATURE INDEX&quot; which measures &quot;temperature anomaly&quot;, which shows for the 2 years the temperature going up. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is, and even more considering both websites share one of their sources, &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Did global temperature increase or drop in the last 2 years?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastEditorUserId="9635" LastEditDate="2019-09-24T11:56:48.573" LastActivityDate="2019-10-28T07:14:37.203" Title="Did global temperature increase or drop in the last 2 years (2017-2018)?" Tags="|climate|temperature|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18047" PostTypeId="2" ParentId="18003" CreationDate="2019-09-22T02:10:31.663" Score="3" Body="&lt;p&gt;Did you try to sketch one of those situations? Try a square grid, define x and y, and then put &lt;span class=&quot;math-container&quot;&gt;$U$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$V$&lt;/span&gt; components onto one of the grid points, which you choose as starting point.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now proceed to implement a). For example, from your starting arrows, go to the next grid point eastwards, and implement &lt;span class=&quot;math-container&quot;&gt;$\frac{dV}{dx}&amp;lt;0$&lt;/span&gt;, i.e. the upwards pointing arrows become smaller as you go eastwards. Do the same for U. Repeat for enough grid points until you see a pattern. Now connect &lt;span class=&quot;math-container&quot;&gt;$U$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$V$&lt;/span&gt; components into the final, two-dimensional velocity vector &lt;span class=&quot;math-container&quot;&gt;$\vec v$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this way you will possibly self-answer your question. I don't know if I can help you more, because I don't know what you mean with \&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I would like to know what does it mean to have&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The end result will be the graphical representation of a vector field. The shear tensor simply measure the amount of shear in each vector field. You will discover that some field structures surprisingly possess shear, while others don't.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2019-09-22T02:10:31.663" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18048" PostTypeId="2" ParentId="8683" CreationDate="2019-09-22T02:56:23.070" Score="2" Body="&lt;p&gt;Answer to that one: What you describe is a measurment, not a calculation.&lt;br&gt;&#xA;The measurment you describe varies the potential difference at a satellites Langmuir probe. The potential difference then attracts or deflects ions, and deflects or attracts electrons. Those electrons and ions &lt;em&gt;are&lt;/em&gt; the current being picked up by the Langmuir probe.&lt;br&gt;&#xA;Then follows a translation of current into local ion or electron densities. Different ion species can be distinguished w.r.t each other because they have different inertia, and thus different arrival times. I'm not sure how many ion species one can distinguish however in this way.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2019-09-22T02:56:23.070" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18050" PostTypeId="2" ParentId="17652" CreationDate="2019-09-22T11:11:43.957" Score="2" Body="&lt;p&gt;&lt;strong&gt;Apparently it is possible for the ionosphere to influence the conditions in the lower atmosphere.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following are relatively recent results &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2008JA014029&quot; rel=&quot;nofollow noreferrer&quot;&gt;from a paper in 2009&lt;/a&gt;, and a summary and up-to-date state-of-the-art can be found in &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/B9780128133712000093?via%3Dihub&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paywalled, upcoming chapter in a book&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As it turns out, at least in the arctic regions, the ionosphere can have quite an impact on the temperatures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geomagnetic storms provide large numbers of energetic electrons, which follow the magnetic field lines. As the magnetic field lines only intersect with the atmosphere in the polar regions, those electrons will preferentially precipicate there. &#xA;What follows is Ozone destruction and generation of &lt;span class=&quot;math-container&quot;&gt;$NO_x$&lt;/span&gt;-species in the Mesosphere and Stratosphere. &lt;span class=&quot;math-container&quot;&gt;$NO_x$&lt;/span&gt; molecules are classical long-lived Ozone killers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Ozone depletion leads to direct heating of the Polar surface of up to &lt;span class=&quot;math-container&quot;&gt;$\Delta T \approx 4.5 K$&lt;/span&gt; by increased UV irradiation. Furthermore, the &lt;span class=&quot;math-container&quot;&gt;$NO_x$&lt;/span&gt; can be transported towards lower latitudes, and geostorm induced chemistry seems to have influenced mid-latitude Ozone concentrations measurable in the past for short times. A nice summary also in the &lt;a href=&quot;https://progearthplanetsci.springeropen.com/articles/10.1186/s40645-015-0051-8&quot; rel=&quot;nofollow noreferrer&quot;&gt;Science case for the EISCAT3D-radar&lt;/a&gt; (not paywalled, and one can skip directly to page 7 where those effects are described and further referenced). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Those indirect effects are intriguing in that, while some might argue that the ionosphere cannot have any influence on the troposphere, it is forgotten that the radiative energy balance links the whole atmosphere. And it is this balance that can be altered by geostorm induced ozone destruction in the middle atmosphere. It's not exactly what OP was going for (no rise in lightning strikes in the troposphere), but the ionosphere knows their own version of lightning , called &lt;a href=&quot;https://en.wikipedia.org/wiki/Sprite_(lightning)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sprites&lt;/a&gt; (also a more recent finding in research), which are sure to appear with those events.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Keep in mind that this is still ongoing research.&lt;br&gt;&#xA;While a correlation of geomagnetic storms with changing polar temperatures has been already noted in the past, and seems undisputed, the exact mechanism responsible for the correlation is still under scrutiny. Personally I feel there must be more to it, as &lt;span class=&quot;math-container&quot;&gt;$4K$&lt;/span&gt; temperature difference just from increased UV irradiation seems a bit much.&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="489" LastEditDate="2019-09-22T11:19:57.813" LastActivityDate="2019-09-22T11:19:57.813" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18052" PostTypeId="2" ParentId="17998" CreationDate="2019-09-22T18:49:49.177" Score="0" Body="&lt;p&gt;It is best to recalculate all major oxide (including TiO2), trace elements are not important. No need to recalculate them.&lt;/p&gt;&#xA;" OwnerUserId="15195" LastActivityDate="2019-09-22T18:49:49.177" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18053" PostTypeId="1" CreationDate="2019-09-22T20:14:17.467" Score="1" ViewCount="739" Body="&lt;p&gt;Please don't answer without citing scientific research which has a general consensus or article from a reputable source based on verifiable research citations.&lt;/p&gt;&#xA;&lt;p&gt;I recently read &lt;a href=&quot;https://www.sciencealert.com/there-is-one-safe-geoengineering-option-that-could-help-reduce-the-carbon-in-our-atmosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; article about a 2017 PNAS study from Griscom et al (link below) that &amp;quot;estimated natural carbon solutions (NCS) (essentially ecosystem regeneration) have the potential to provide up to 37 percent of the CO2 mitigation that we'd need through 2030, for a 66 percent chance of holding warming to below 2°C.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;More specifically, what is the most cost-effective solution? Most geoengineering solutions have significant risks or unknowns which greatly reduce their benefit. Reducing fossil fuel use immediately will reduce short-term economic output with replacing with renewables and alternatives. Maybe simply paying drivers incentives to use alternative vehicles is most-cost effective, as transportation is the largest percentage of greenhouse gas emissions in the US (&lt;a href=&quot;https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions&quot; rel=&quot;nofollow noreferrer&quot;&gt;EPA&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;So what is the most cost-effective and how much money would it take to get it done? Global energy-related CO2 emissions were 33.1 Gt CO2 in 2018 according the [IEA report][6]. Apparently from the Griscom study, 10 USD MgCO2e−1 is the &amp;quot;current cost of emission reduction efforts underway and current prices on existing carbon markets&amp;quot; from 2017. 1Gt = 1Pg = 1000Mt = 1000Tg = 10^9 tonnes &lt;a href=&quot;https://en.wikipedia.org/wiki/Tonne#Derived_units&quot; rel=&quot;nofollow noreferrer&quot;&gt;metric&lt;/a&gt;, and 1Mg = 1 tonne, so our CO2 emissions cost us 10*10^9 or 10 billion USD per year. For reference, global GDP is at US$84.84 trillion for 2018, meaning reducing our entire emissions to zero would cost all of 0.0001% of global GDP.&lt;/p&gt;&#xA;&lt;p&gt;As as corollary, if all benefits of NCS to uncalculated ecosystem services were included, would they be the most cost-effective, and what is the average ROI on research investment to calculate them?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;To the Mods&lt;/strong&gt;: I've changed the title to match the narrow question specified in the body of the question. I've provided an answer that is very specific using calculated figures from cited references. What else would you like to make the question more narrow?&lt;/p&gt;&#xA;&lt;p&gt;Griscom et al, &lt;a href=&quot;https://www.pnas.org/content/114/44/11645&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.pnas.org/content/114/44/11645&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17914" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-09-30T18:42:29.140" Title="What is the most cost-effective solution to climate change based on scientific evidence?" Tags="|climate-change|" AnswerCount="2" CommentCount="9" ClosedDate="2019-09-24T15:08:38.693" ContentLicense="CC BY-SA 4.0" />
  <row Id="18054" PostTypeId="2" ParentId="18053" CreationDate="2019-09-22T20:14:59.170" Score="1" Body="&lt;p&gt;In researching my question to provide what is known so far I found the following information. I won't accept my own answer unless it gets the most upvotes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found this &lt;a href=&quot;https://www.drawdown.org/solutions-summary-by-rank&quot; rel=&quot;nofollow noreferrer&quot;&gt;ranked list&lt;/a&gt; from 'Project Drawdown' (PD) that states Managing Refrigerants is the number one solution by GT CO2 reduction by total, but with an unknown cost. Offshore wind turbines (OFTs) seems to be the best solution by total reduction. Electric vehicles (EVs) has the highest savings, but with also the highest cost. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Dividing the reduction amount by the savings leads to OVTs at 11.4 GT CO2 reduction per trillion USD a year (GCR/TUY), then Solar Farms (SFs) at 7.35 and EVs at 1.11 for the top three &lt;strong&gt;by savings&lt;/strong&gt;. However, if all are &lt;a href=&quot;https://docs.google.com/spreadsheets/d/1kgVcHUzpMbBsJNer6WPIv_vhhLU_IB1DImVrWg7Jw3o/edit?usp=sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;calculated and ranked&lt;/a&gt;, the most reduction by savings is Tree Intercropping at 778 and methane digesters small at 137, the most reduction &lt;strong&gt;by cost&lt;/strong&gt; is Nuclear Energy at 18254 and then Solar Water at 2033, but including the costs with negative numbers (not sure what that means) it's Landfill Methane at -1374 and Solar Farms at -458 GCR/TUY.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not sure if they're including the cost of nuclear accidents or waste storage, since waste storage at least in the US has not been reconciled, and may not be &lt;a href=&quot;https://www.reuters.com/article/us-energy-nuclearpower/nuclear-energy-too-slow-too-expensive-to-save-climate-report-idUSKBN1W909J&quot; rel=&quot;nofollow noreferrer&quot;&gt;fast enough&lt;/a&gt;, so using Solar Water at 2.033 GCR/BillionUY, it would cost 16.3 billion USD per year to reduce the CO2 we emit for energy. Based on a single strategy, that's 2.11 dollars per person in the world (&lt;a href=&quot;https://www.worldometers.info/world-population/&quot; rel=&quot;nofollow noreferrer&quot;&gt;7.7 billion&lt;/a&gt;) and $12.50 for every person in the developed world (&lt;a href=&quot;https://www.nextbigfuture.com/2018/11/developed-country-population-from-17-to-over-50-of-world-by-2050.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;1.3 billion&lt;/a&gt;). Is this correct?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the PD FAQs they state, &quot;Carbon pricing is a policy mechanism to implement solutions and not in itself a solution to global warming. It is the single most impactful policy proposal that would accelerate the adoption of every solution enlisted.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Adding a few other solutions I've found:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;CO2 recapture in concrete can reduce it's emissions by 40% (it is 8% of global) and also the energy used. &lt;a href=&quot;https://www.solidiatech.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.solidiatech.com/&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0304389412011156?via%3Dihub&quot; rel=&quot;nofollow noreferrer&quot;&gt;Red mud as a carbon sink&lt;/a&gt;, using the hydroxides from aluminum smelting because of the high solubility of CO2 in them.&lt;/li&gt;&#xA;&lt;li&gt;Relying on rock &lt;a href=&quot;https://phys.org/news/2019-09-theory-earth-climate-million-years.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;weathering&lt;/a&gt; from carbonic acid in rain and because &quot;&lt;a href=&quot;https://phys.org/news/2018-08-carbon-filled-oceans-affect-tiny-important.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Coccolithophores&lt;/a&gt; account for half of the calcium carbonate creation in the ocean&quot;, some kind of &lt;a href=&quot;https://www.frontiersin.org/10.3389/conf.FMARS.2018.06.00034/event_abstract?sname=IMMR_18_%7C_International_Meeting_on_Marine_Research_2018&quot; rel=&quot;nofollow noreferrer&quot;&gt;phytoplankton&lt;/a&gt; farms harnessing their &quot;potential for carbon sequestration but also for the production of high value products, such as fatty acids and pigments.&quot;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="17914" LastEditorUserId="17914" LastEditDate="2019-09-30T18:42:29.140" LastActivityDate="2019-09-30T18:42:29.140" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18056" PostTypeId="1" AcceptedAnswerId="18065" CreationDate="2019-09-23T04:47:48.067" Score="4" ViewCount="226" Body="&lt;p&gt;&lt;a href=&quot;https://space.stackexchange.com/a/38999/12102&quot;&gt;This answer&lt;/a&gt; pointed me to the Wikipedia page for &lt;a href=&quot;https://en.wikipedia.org/wiki/Farouk_El-Baz&quot; rel=&quot;nofollow noreferrer&quot;&gt;Farouk El-Baz&lt;/a&gt; in which the &lt;a href=&quot;https://en.wikipedia.org/wiki/Farouk_El-Baz#Desert_research_and_theories&quot; rel=&quot;nofollow noreferrer&quot;&gt;desert research and theories&lt;/a&gt; subsection says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;During the past 20 years in his research at Boston University, &lt;strong&gt;El-Baz has utilized satellite images to better understand the origin and evolution of desert landforms. He is credited with providing evidence that the desert is not man-made, but the result of major climatic variations.&lt;/strong&gt; His research uncovered numerous sand-buried rivers and streams in the Sahara based on the interpretation of radar images.&lt;/p&gt;&#xA;&lt;p&gt;These former water courses lead into depressions in the terrain, which he theorized must contain groundwater. His analysis of these data resulted in the location of groundwater in the arid terrains of Egypt, Oman, and the United Arab Emirates (U.A.E.), and perhaps Darfur in Sudan (unless it dried up).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I was surprised to read that the &amp;quot;origin and evolution of desert landforms&amp;quot; was ever considered to have an anthropocenic component.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; When was it ever considered that the desert might be &amp;quot;man-made&amp;quot;, or otherwise anthropocenically-induced? Is it possible to know which desert was thought to be man-made that El-Baz proved wasn't? Or does the passage refer to &lt;em&gt;all deserts?&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditorDisplayName="user12525" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-09-24T18:48:50.950" Title="When was it ever considered that the desert might be &quot;man-made&quot;, or otherwise anthropocenically-induced?" Tags="|geomorphology|desert|desertification|" AnswerCount="2" CommentCount="15" ContentLicense="CC BY-SA 4.0" />
  <row Id="18057" PostTypeId="2" ParentId="18035" CreationDate="2019-09-23T10:33:57.123" Score="5" Body="&lt;p&gt;Explosive volcanic events happen mostly because of saturation in gases, and increase in pressure above the strength of the top of the magma chamber. As the magma decompresses or cools, H&lt;sub&gt;2&lt;/sub&gt;O (mostly), CO&lt;sub&gt;2&lt;/sub&gt; (also important), and other gases such as H&lt;sub&gt;2&lt;/sub&gt;S, SO&lt;sub&gt;2&lt;/sub&gt;, HCl, etc, form bubbles and increase in volume. If the magma chamber is confined, there is also an increase in pressure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An obvious corollary is that gases have to be present. If the magma is mostly dry and volatile-free, there are no volatile species to form bubbles and the magma cannot explode.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another factor is the viscosity of the magma. The less viscous it is, the easier it is for the magma to flow (and not build up pressure) and also the easier it is for bubbles to escape the magma. Viscosity of magma depends on temperature (hotter = less viscous), composition (more alkalis = less viscous), crystal content (less crystals = less viscous).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Taken together, a hot alkali magma without crystals and no volatile species will flow, whereas a cold partly crystallised wet sub-alkali magma will probably explode, even if they have exactly the same SiO&lt;sub&gt;2&lt;/sub&gt; contents.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-09-23T10:33:57.123" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18058" PostTypeId="1" AcceptedAnswerId="18063" CreationDate="2019-09-23T12:36:38.003" Score="1" ViewCount="63" Body="&lt;p&gt;Imagine a &lt;a href=&quot;https://en.wikipedia.org/wiki/Meridian_(geography)&quot; rel=&quot;nofollow noreferrer&quot;&gt;meridian&lt;/a&gt; that moves over the Earth's surface such that it remains at the longitude that corresponds to a particular solar time (e.g. midday). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This meridian would remain stationary relative to the Sun as the Earth revolves under it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a name for such a meridian?&lt;/p&gt;&#xA;" OwnerUserId="17917" LastEditorUserId="6031" LastEditDate="2019-09-23T12:43:50.987" LastActivityDate="2019-09-24T16:31:29.400" Title="Is there a name for a &quot;moving meridian&quot; corresponding to particular solar time?" Tags="|terminology|earth-observation|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18060" PostTypeId="1" CreationDate="2019-09-23T19:21:02.760" Score="1" ViewCount="42" Body="&lt;p&gt;Population reduction is not envisaged as a practical (never mind humane) solution to CO2 emission reduction as far as I can tell.&lt;/p&gt;&#xA;&lt;p&gt;I stumbled however on a paper discussing the estimated effects of such a past event, i.e. Europeans colonizing the Americas, &lt;a href=&quot;https://doi.org/10.1016/j.quascirev.2018.12.004&quot; rel=&quot;nofollow noreferrer&quot;&gt;Koch et al. (2019)&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Estimates European arrival in 1492 lead to 56 million deaths by 1600. [...]&lt;/p&gt;&#xA;&lt;p&gt;European epidemics removed 90% (IQR 87–92%) of the indigenous population over the next century. This resulted in secondary succession of 55.8 Mha (IQR 39.0–78.4 Mha) of abandoned land, sequestering 7.4 Pg C (IQR 4.9–10.8 Pg C), equivalent to a decline in atmospheric CO2 of 3.5 ppm (IQR 2.3–5.1 ppm CO2). Accounting for carbon cycle feedbacks plus LUC outside the Americas gives a total 5 ppm CO2 additional uptake into the land surface in the 1500s compared to the 1400s, 47–67% of the atmospheric CO2 decline.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Are there any other depopulation events for which such CO2-reduction estimates were derived?&lt;/p&gt;&#xA;" OwnerUserId="11964" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-09-23T19:21:02.760" Title="CO2 reduction by depopulation" Tags="|co2|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18061" PostTypeId="2" ParentId="18056" CreationDate="2019-09-23T20:27:08.483" Score="-3" Body="&lt;p&gt;All the major deserts are naturally formed by climate change in ancient times. Much of the Sahara, as recently as six or seven thousand years ago, was savannah of a sort now found in East Africa, and with a similar flora and fauna (acacia, crocodiles, giraffes, gazelle, lions, ostriches etc). However, deserts can be man made, and a good example of that is the dust bowl of mid-west USA in the 1930s. The dust bowl was caused by bad farming methods which made the land unable to withstand a few years of drought. Wind created enormous dust storms of a kind which sometimes occur in the Sahara or Australia, and this blew the topsoil away, so farmers had to leaved their land and find work in the cities. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Special farming techniques managed to restore most of this man made desert in the forties and fifties, so I think I'm right in saying that most of it is now productive farmland again, but not so productive as it would have been if the dust bowl had never happened. Another example can be found in the Sahel, where overgrazing by livestock has transformed some areas into desert over the last 50 years.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-23T20:27:08.483" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18063" PostTypeId="2" ParentId="18058" CreationDate="2019-09-24T01:07:47.793" Score="3" Body="&lt;p&gt;This is better suited for English Language &amp;amp;Usage SE, but the word you're looking for is &lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Isochron&lt;/h2&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;an imaginary line or a line on a chart connecting points at which an event occurs simultaneously or which represents the same time or time difference&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(Source: &lt;a href=&quot;https://www.merriam-webster.com/dictionary/isochron&quot; rel=&quot;nofollow noreferrer&quot;&gt;Merriam-Webster&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Isochrons are typically used in diagrams rather than maps, for techniques like rock dating, where correlating things by time is more important. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But cartographers are used to putting all types of &lt;a href=&quot;http://wiki.gis.com/wiki/index.php/Isarithmic_map&quot; rel=&quot;nofollow noreferrer&quot;&gt;isarithm&lt;/a&gt;s on maps, and would understand what an isochron was meant on a map.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The trick is to define &quot;same time&quot; as &quot;same solar time&quot;, giving you the &quot;moving meridian&quot; you're looking for.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could contrive a more specific term like &lt;strong&gt;&lt;em&gt;isoheliochron&lt;/em&gt;&lt;/strong&gt; but it hardly seems worth the effort, because they're pretty boring on a map.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2019-09-24T16:31:29.400" LastActivityDate="2019-09-24T16:31:29.400" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18064" PostTypeId="1" CreationDate="2019-09-24T03:24:59.180" Score="1" ViewCount="49" Body="&lt;p&gt;Thunderstorms happen after a period of warm weather. There are times though in the summer after it’s been warm for a while and even after it was 95 degrees Fahrenheit, the thunderstorms they predicted just ends up being rain without lightning and thunder even when it was hot outside. Why is this?&lt;/p&gt;&#xA;" OwnerUserId="17923" LastActivityDate="2019-09-24T03:24:59.180" Title="Why it doesn’t always rain with lightning and thunder when it’s hot" Tags="|meteorology|weather-forecasting|thunderstorm|" AnswerCount="0" CommentCount="3" ClosedDate="2019-09-25T09:09:59.123" ContentLicense="CC BY-SA 4.0" />
  <row Id="18065" PostTypeId="2" ParentId="18056" CreationDate="2019-09-24T07:51:36.977" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;El-Baz has utilized satellite images to better understand the origin&#xA;  and evolution of desert landforms. He is credited with providing&#xA;  evidence that the desert is not man-made, but the result of major&#xA;  climatic variations.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Does the passage refer to all deserts?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Geolmorphologists classify deserts as zones that take place in climatic &lt;strong&gt;arid regions&lt;/strong&gt; where rainfall is relatively low, there are extreme daily temperature variations and the vegetable cover is reduced or non-existent. The climatic conditions result in desert typical forms as &lt;a href=&quot;https://en.wikipedia.org/wiki/Hamada&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;hamadas&lt;/em&gt;&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Caliche&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;caliches&lt;/em&gt;&lt;/a&gt;, or &lt;em&gt;dunes&lt;/em&gt;. (Gutiérrez Elorza, M., 2008).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is important to note not every arid region is a desert, but every desert, with particular forms, is an arid (or hyperarid) zone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CafSh.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CafSh.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.researchgate.net/figure/World-map-of-arid-and-semi-arid-lands_fig1_261416592&quot; rel=&quot;nofollow noreferrer&quot;&gt;research.net&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question is: can Climate Change and deforestation create deserts?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Answer is Climate Change and deforestation can create new arid zones. It can create the conditions to expand existant deserts, but the typical desert forms take some time to form, so deserts as El-Baz have not (yet) grow because of our actions on the planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, other deserts as Sahara have expanded his area in the last century (Thomas, N. et al., 2017). The article of this asseveration quotes (anthropological) Climate Change as the main factor of this expansion. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So answering your question the passage you quote does not refer to all deserts if you consider man-made something that result from our emissions of greenhouse gases to the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Gutiérrez Elorza, Mateo (2008):&lt;/strong&gt; &lt;em&gt;&quot;Geomorfología&quot;&lt;/em&gt;, Ed. Prentice Hall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/JCLI-D-17-0187.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Thomas, Natalie and Nigam, Sumant (2017):&lt;/strong&gt; &lt;em&gt;&quot;Twentieth-Century Climate Change over Africa: Seasonal Hydroclimate Trends and Sahara Desert Expansion&quot;&lt;/em&gt;. Journal of Climate, vol 31.&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user12525" LastEditDate="2019-09-24T18:48:50.950" LastActivityDate="2019-09-24T18:48:50.950" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18067" PostTypeId="1" AcceptedAnswerId="19129" CreationDate="2019-09-24T09:39:50.597" Score="1" ViewCount="488" Body="&lt;p&gt;Does anybody here have any experience with editing wrfchemi outputs from the prep_chem utility so that I overwrite the file with my own emissions?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am knowledgeable in python, but I am not that well oriented with the manipulation of NetCDF files. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I want to do, basically, is to use my own emissions inside the WRF/Chem model&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;I have a shapefile of emissions (gridded) with each grid having a value for the emissions.&lt;/li&gt;&#xA;&lt;li&gt;I want to convert this to a readable format for the WRF/Chem; however, I think editing the wrfchemi files by prep_chem would be easier? (Tell me if not)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I have read the emissions guide of the WRF/Chem, but it does not really expound on details about this especially about the following&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;How to deal with the speciation (my shapefile has only PM10 and PM2.5). where exactly do I place this in the new emissions file (the edited wrfchemi)I want. There are many pm species there (like pm2.5 nucleation mode, pm, etc). I am not sure what weights to put on these.&lt;/li&gt;&#xA;&lt;li&gt;My emissions are not time dependent, and what do I do when I edit the wrfchemi file for this. (the wrfchemi files I have now are also not time dependent)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Hoping someone could help out with this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;" OwnerUserId="17926" LastEditorUserId="17926" LastEditDate="2019-09-26T09:52:30.387" LastActivityDate="2020-03-18T17:36:12.293" Title="WRF/Chem: Editing NetCDF (wrfchemi files) for own emissions" Tags="|weather-forecasting|wrf|netcdf|wrf-chem|emissions|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18068" PostTypeId="2" ParentId="18046" CreationDate="2019-09-24T09:43:00.160" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Did global temperature increase or drop in the last 2 years?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Before I answer the question, I need to add the caveat that climate change does not say that every year will be warmer than the previous one. Events such as El Ninos and La Ninas can make the global temperature spike or drop in any one year. The Pacific Ocean dumps huge amounts of pent up heat into the atmosphere during El Nino events.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2014 saw the start of an El Nino event that briefly stalled but then became one of the largest such events ever observed. The 2014-2016 El Nino made 2015 and 2016 the warmest years on record -- so far. 2017 and 2018 were a bit cooler than 2015 and 2016. They were however warmer than every year on record prior to 2015.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2019 most likely will not be warmer than 2016, but it might well beat 2015 as the second warmest year on record. And that is without the help of a massive El Nino event.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2019-09-24T09:48:07.737" LastActivityDate="2019-09-24T09:48:07.737" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18069" PostTypeId="1" AcceptedAnswerId="18070" CreationDate="2019-09-24T12:42:01.270" Score="6" ViewCount="120" Body="&lt;p&gt;Does muscovite occur as a contact metamorphism mineral, with dacitic intrusion into dacitic rocks?&lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="6467" LastEditDate="2019-09-29T22:47:10.610" LastActivityDate="2021-12-08T16:45:29.073" Title="Does muscovite occur as a contact metamorphism mineral?" Tags="|mineralogy|metamorphism|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18070" PostTypeId="2" ParentId="18069" CreationDate="2019-09-24T13:04:11.897" Score="7" Body="&lt;p&gt;Yes, wikipedia page for muscovite tells:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Muscovite is the most common mica, found in granites, pegmatites,&#xA;gneisses, and schists, &lt;strong&gt;and as a contact metamorphic rock&lt;/strong&gt; or as a&#xA;secondary mineral resulting from the alteration of topaz, feldspar,&#xA;kyanite, etc.&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Muscovite&quot; rel=&quot;noreferrer&quot;&gt;Muscovite, Wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;As always, you need to corroborate wikipedia is correct, but there are several papers that talk about muscovite on contact metamorphism environments, you can do your own search on a scientifical database.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/0016703775901349&quot; rel=&quot;noreferrer&quot;&gt;Here is an example&lt;/a&gt; about a paper that deals with muscovite found on contact aureole of Duluth Complex, Minnesota.&lt;/p&gt;&#xA;&lt;p&gt;So yes it is a mineral phase formed in that conditions of increased temperature due to an intrusion.&lt;/p&gt;&#xA;&lt;p&gt;For you specific question about contact metadacites, yes too, they can develop muscovite as shown in &lt;a href=&quot;https://books.google.es/books?id=bOZHx7ITq24C&amp;amp;pg=PA16&amp;amp;lpg=PA16&amp;amp;dq=dacite%20muscovite&amp;amp;source=bl&amp;amp;ots=d0nxV_LnYT&amp;amp;sig=ACfU3U1UEf1HghTYFbmWmZBKq29QbkFPzg&amp;amp;hl=es&amp;amp;sa=X&amp;amp;ved=2ahUKEwj0uObtiOrkAhWqDmMBHZm2BVAQ6AEwEHoECAkQAQ#v=onepage&amp;amp;q=dacite%20muscovite&amp;amp;f=false&quot; rel=&quot;noreferrer&quot;&gt;this book&lt;/a&gt; about US geology.&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorUserId="-1" LastEditorDisplayName="user12525" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-09-24T18:36:28.593" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18071" PostTypeId="2" ParentId="18053" CreationDate="2019-09-24T13:18:56.433" Score="1" Body="&lt;p&gt;We are not going to hold warming below 2 degree C. We might as well stop mentioning that figure.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The idea with the least resistance from the financial market sector (this sector depends upon the idea of growth to sell and trade product) is recapture of carbon or some other idea to cool the atmosphere like the plan Bill Gates was investigating, sending multiple! jet missions up to spray chemicals under the idea of cooling the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don’t know exactly what Spencer meant by stop digging, and I don’t want to put words in his mouth. For me, it means we must take into account the 2nd Law of Thermodynamics as we devise our solutions for recapture, and other ideas. Everything must be super, super efficient. Of course, the 2nd law is still there, but super efficiency is relatively better. We certainly don’t need to be building sea walls on top of sea walls in a losing battle. It’s better just to move. Multiple, multiple, jet aircraft missions are also highly questionable, at least at first look. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as I know (and this is taxing my old brain) but the 1972 Club of Rome-MIT report (not exactly about Climate change per se) was one of the few studies to de facto take into account the 2nd Law. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We find ourselves doing more and more work, and creating more “chaos” to maintain, for instance, the fiction of our financial markets for never-ending growth. More work even just to maintain a certain equilibrium. We are digging ourselves deeper and deeper into a hole to stay even, much less grow. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is hard to over-emphasize the sheer brute power of the financial market sector. You could almost say that the world military power exists to maintain this sector, and this sector lives in the future. A bond trader goes to work, he works 30 years ahead of us, or more.   This sector craves predictability, and the idea seems to be spew the CO2 and other climate gases, and recapture or some other such scheme. I think we need to realize these schemes are taxed by the 2nd Law. &lt;/p&gt;&#xA;" OwnerUserId="12693" LastEditorUserId="12693" LastEditDate="2019-09-24T14:50:02.043" LastActivityDate="2019-09-24T14:50:02.043" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18072" PostTypeId="1" CreationDate="2019-09-24T19:34:05.683" Score="2" ViewCount="1118" Body="&lt;p&gt;I've always wondering why the oxygen in the atmosphere remains so perfectly at the level required for air-breathing life. What causes it to remain so perfect?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, a side question, why aren't their pressure bubbles with higher or lower levels of oxygen that could drift through a town and make it hard/impossible to breathe?&lt;/p&gt;&#xA;" OwnerUserId="17929" LastActivityDate="2019-09-25T17:11:46.097" Title="Why does atmospheric oxygen remain so &quot;constant&quot;?" Tags="|atmosphere|oxygen|" AnswerCount="1" CommentCount="1" ClosedDate="2019-09-25T12:26:18.710" ContentLicense="CC BY-SA 4.0" />
  <row Id="18074" PostTypeId="1" CreationDate="2019-09-25T04:02:59.993" Score="1" ViewCount="114" Body="&lt;p&gt;My family is taking road trip in  Quebec Oct 4 to 18, 2019. &lt;a href=&quot;https://www.google.com/maps/dir/Mont+Tremblant,+Mont-Tremblant,+QC+J8E+0A8/Montr%C3%A9al,+QC/La+Mauricie+national+Park,+Saint-Mathieu-du-Parc,+QC/Quebec+City,+QC/Saguenay,+QC/Mingan,+QC/Gasp%C3%A9,+QC/@48.0658196,-74.7787133,5.73z/data=!4m44!4m43!1m5!1m1!1s0x4ccf82ae867fd6c1:0x8de31f7401bd0cf4!2m2!1d-74.5528513!2d46.2199441!1m5!1m1!1s0x4cc91a541c64b70d:0x654e3138211fefef!2m2!1d-73.567256!2d45.5016889!1m5!1m1!1s0x4cc65d3ab03ba8a3:0x8830c9fe400dcb9b!2m2!1d-72.967707!2d46.6498854!1m5!1m1!1s0x4cb8968a05db8893:0x8fc52d63f0e83a03!2m2!1d-71.2079809!2d46.8138783!1m5!1m1!1s0x4cc02768304203bd:0xfe107b2c38d93d34!2m2!1d-71.0684923!2d48.4280529!1m5!1m1!1s0x4c850d03e6348c83:0x1c9194573345042b!2m2!1d-64.023161!2d50.291457!1m5!1m1!1s0x4c9bbf23b75f9eab:0x4971fdae95f10155!2m2!1d-64.4869017!2d48.8316351!3e0?hl=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;I posted our route on Google&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9B3ZN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9B3ZN.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just double checking &lt;a href=&quot;https://www.swpc.noaa.gov/products/aurora-3-day-forecast&quot; rel=&quot;nofollow noreferrer&quot;&gt;how interpret NOAA's Aurora 3 day forecast&lt;/a&gt;? It shows aurora borealis any where north to Quebec City on 2019-09-28 1900 to 2200 Quebec time. Right? Quebec time is &lt;a href=&quot;https://en.wikipedia.org/wiki/Universal_Time&quot; rel=&quot;nofollow noreferrer&quot;&gt;UT&lt;/a&gt; minus 5. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CWnoJ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CWnoJ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user17042" LastActivityDate="2019-09-25T04:02:59.993" Title="How interpret NOAA Aurora 3 day Forecast?" Tags="|auroras|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18075" PostTypeId="1" CreationDate="2019-09-25T04:43:55.337" Score="1" ViewCount="34" Body="&lt;p&gt;I found just &lt;a href=&quot;https://earthscience.stackexchange.com/q/18074/17042&quot;&gt;3 day forecast on NOAA&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Is there longer forecast?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Are there data for past years? Past performance is no guarantee of future results. But seeing area of visible aurora for Oct. 2018, 2017, 2016... assists a little???&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerDisplayName="user17042" LastActivityDate="2019-09-25T04:43:55.337" Title="How can I see aurora borealis predictions on specific future date more than 3 days?" Tags="|auroras|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18076" PostTypeId="2" ParentId="18072" CreationDate="2019-09-25T10:48:57.980" Score="1" Body="&lt;p&gt;The main reasons the atmospheric oxygen remains constant are:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The sheer quantity of it. Not even a large forest fire will&#xA;measurably deplete it. Most of it is fossil oxygen created many&#xA;millions of years ago by photosynthetic organisms.&lt;/li&gt;&#xA;&lt;li&gt;It is constantly being replenished by photosynthetic organisms,&#xA;mainly in the ocean.&lt;/li&gt;&#xA;&lt;li&gt;Measurements of the percentage of oxygen in the atmosphere are a&#xA;modern phenomenon. There are no accurate measurements of atmospheric&#xA;oxygen in previous geological periods, but we know the percentage&#xA;has not always been 21 percent.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="17166" LastEditorDisplayName="user12525" LastEditDate="2019-09-25T17:11:46.097" LastActivityDate="2019-09-25T17:11:46.097" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18078" PostTypeId="1" CreationDate="2019-09-26T00:50:10.033" Score="10" ViewCount="263" Body="&lt;p&gt;CNN's &lt;a href=&quot;https://edition.cnn.com/travel/article/mont-blanc-glacier-collapse-intl-scli/index.html&quot; rel=&quot;noreferrer&quot;&gt;Mont Blanc glacier could &lt;strong&gt;collapse&lt;/strong&gt; at any moment, Italy warns&lt;/a&gt; says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A staggering 250,000 cubic meters (8.8 million cubic feet) of ice could break away from the Planpincieux glacier on the Grandes Jorasses mountain in the Mont Blanc massif, experts at the Valle d'Aosta regional government and the Fondazione Montagna Sicura (Safe Mountain Foundation) &lt;a href=&quot;http://www.comune.courmayeur.ao.it/comune/news_scheda.php?acc=&amp;amp;nId=1263&quot; rel=&quot;noreferrer&quot;&gt;reported&lt;/a&gt; in an analysis published this week.&lt;/p&gt;&#xA;&lt;p&gt;While it's impossible to predict the exact timing of the &lt;strong&gt;collapse&lt;/strong&gt;, observations in August and September showed that the glacier was shifting at a speed of 50 to 60 centimeters (20 to 24 inches) a day, experts said.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;These phenomena once again show that the mountain is going through a phase of strong change due to climatic factors, therefore it is particularly vulnerable,&amp;quot; Stefano Miserocchi, mayor of nearby Courmayeur, &lt;a href=&quot;http://www.comune.courmayeur.ao.it/comune/news_scheda.php?acc=&amp;amp;nId=1263&quot; rel=&quot;noreferrer&quot;&gt;said in a statement&lt;/a&gt;. &amp;quot;In this case, it's a temperate glacier particularly sensitive to high temperatures.&amp;quot;As a precautionary measure, Miserocchi ordered the closure of roads in the Val Ferret valley and the evacuation of mountain huts in the Rochefort area.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The caption of the image in the link (shown below) is labeled Figure 22, so presumably it's from some much larger report.&lt;/p&gt;&#xA;&lt;p&gt;I'm curious about the choice of the word &amp;quot;collapse&amp;quot;. What is it exactly that the glacier might do? Will it collapse in the same way that a &lt;a href=&quot;https://en.wikipedia.org/wiki/Souffl%C3%A9#In_popular_culture&quot; rel=&quot;noreferrer&quot;&gt;Soufflé collapses&lt;/a&gt;, or is this more like an avalanche, or does the whole glacier just start sliding much faster, like several meters per day instead of several tens of centimeters currently?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Qukpq.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Qukpq.jpg&quot; alt=&quot;&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2021-03-29T04:46:28.657" Title="What does &quot;glacier collapse&quot; mean?" Tags="|glaciology|" AnswerCount="4" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18080" PostTypeId="2" ParentId="18078" CreationDate="2019-09-26T08:11:38.503" Score="-3" Body="&lt;p&gt;It means that large parts might break off and cause an ice avalanche or series of avalanches which would go crashing down the valley, killing or destroying anything which got in its way.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-26T08:11:38.503" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18081" PostTypeId="1" CreationDate="2019-09-26T14:18:41.050" Score="3" ViewCount="117" Body="&lt;p&gt;I'm trying to verify that some code I have is running correctly when calculating the Coulomb stress change. So for a example I have a fault with :&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Length = 70 m,&#xA;Slip= 0.004 m,&#xA;Orientation(strike/dip/rake) = 93/71/-29&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and the regional stress tensor. How do I go about calculataing the normal and shear stress for this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many Thanks&lt;/p&gt;&#xA;&#xA;&lt;p&gt;James&lt;/p&gt;&#xA;" OwnerUserId="17939" LastActivityDate="2019-09-26T14:18:41.050" Title="Calculate normal and shear stresses with fault plane dimensions, slip, orientation and regional stress tensor" Tags="|geology|structural-geology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18082" PostTypeId="1" CreationDate="2019-09-26T16:15:58.447" Score="3" ViewCount="507" Body="&lt;p&gt;I'm currently studying cold environments, looking at periglacial processes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've been looking into gelifluction and solifluction as processes of periglaciation. The two terms seem to be used, mostly, without differentiation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I am given to understand that there is a difference between the two processes. Apparently gelifluction is more distinct to periglaciation than solifluction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could anyone explain the difference between the two processes, if at all there is a difference?&lt;/p&gt;&#xA;" OwnerUserId="14152" LastEditorDisplayName="user12525" LastEditDate="2019-09-26T17:49:17.603" LastActivityDate="2019-09-27T10:19:51.277" Title="Gelifluction vs Solifluction" Tags="|geomorphology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18083" PostTypeId="1" CreationDate="2019-09-26T16:23:39.857" Score="1" ViewCount="44" Body="&lt;p&gt;My aunt gave me this rock.  She has had for years.  She was given it by a relative who passed many years ago.  She said it was called a Tuffy (not sure which way it should be spelled) and that it came from Neveda.  I couldn't find any info on it.  Could you help.  Thank you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zst6h.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zst6h.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17941" LastActivityDate="2019-09-26T19:54:36.460" Title="Information on this rock, and identity?" Tags="|geology|" AnswerCount="1" CommentCount="2" ClosedDate="2019-09-27T07:30:06.320" ContentLicense="CC BY-SA 4.0" />
  <row Id="18085" PostTypeId="2" ParentId="18083" CreationDate="2019-09-26T19:54:36.460" Score="1" Body="&lt;p&gt;Typically we are not answering Rock Id questions, though this is a somewhat unique question because the rock is unique.  Your rock is likely a tufa (never heard it called tuffy).  It is a rock that is formed when water with high carbonate content is released to the surface.  Depending on the conditions at the surface the dissolved carbonate comes out of solution, this can be through cooling, depressurization and reduction of the partial pressure of CO2, or through biological precipitation by organisms such as blue-green algae.  There may also be other means that the deposition occurs but overall the water solution is initially oversaturated with the carbonate minerals.  These deposit out in the patterns shown on your sample.  If you were to perform an acid test your rock should show a strong reaction.  The area around the California Nevada boundary has a large number of locations with this type of deposit both active, Mono Lake, and inactive like the Trona Pinnacles.  Nevada itself has some of these deposits in the Black Rock Desert, Pyramid Lake and Fly Ranch areas.  Deposits are likely found world wide but these are the ones I am familiar with.  The pattern of deposition on your rock suggests to me an association with algae when it was deposited.  See the following sites:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Tufa&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Tufa&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.blackrockdesert.org/wiki/index.php?title=Geology&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.blackrockdesert.org/wiki/index.php?title=Geology&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2019-09-26T19:54:36.460" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18086" PostTypeId="1" AcceptedAnswerId="18116" CreationDate="2019-09-27T01:00:08.677" Score="1" ViewCount="669" Body="&lt;p&gt;According to this,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nasa.gov/feature/goddard/2019/2018-s-biggest-volcanic-eruption-of-sulfur-dioxide&quot; rel=&quot;nofollow noreferrer&quot;&gt;2018’s Biggest Volcanic Eruption of Sulfur Dioxide&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In extreme cases, like the 1991 eruption of Mount Pinatubo in the&#xA;  Philippines, these tiny aerosol particles can scatter so much sunlight&#xA;  that they cool the Earth’s surface below.   Mount Pinatubo’s violent&#xA;  eruption injected about 15 million tons of sulfur dioxide into the&#xA;  stratosphere. The resulting sulfuric acid aerosols remained in the&#xA;  stratosphere for about two years, and cooled the Earth’s surface by a&#xA;  range of 1 to 2 degrees Fahrenheit.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But according to this, &lt;a href=&quot;https://www.ranker.com/list/the-worst-volcanic-eruptions-in-history/drake-bird&quot; rel=&quot;nofollow noreferrer&quot;&gt;Worst volcanic eruptions in human history&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the worst volcanic eruption in human history injected 400 million tons&#xA;  of gas&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(26,6 times more than Pinatubo's eruption) though I guess the composition of the gas could be different, and &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the Earth began to cool and 1816 became known as &quot;The Year Without&#xA;  Summer&quot; because of the low temperatures, which killed crops and led to&#xA;  mass starvation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Is it know what global temperature Earth had this year and how much in degrees celsius or fahrenheit temperature changed?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastEditorUserId="9635" LastEditDate="2019-09-30T00:38:27.540" LastActivityDate="2019-10-06T18:42:14.233" Title="How much did the worst volcanic eruption in human history affect global temperature?" Tags="|climate|volcanic-eruption|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18088" PostTypeId="2" ParentId="18086" CreationDate="2019-09-27T06:30:02.040" Score="3" Body="&lt;p&gt;The largest volcanic eruption in human history was the Toba eruption on Sumatra about 75,000 years ago. There is still a huge lake, Lake Toba, in the crater. It dwarfed Thera, Krakatoa and Tambora. The Tambora  eruption on the Indonesian island of Sumbawa occurred in 1815, and was the largest eruption in historical times, also dwarfing the other two. It caused bad weather and lower temperatures around the world, including Europe, for about a year. The much larger Toba eruption must have had even more drastic short term effects lasting for years, but strangely enough doesn't seem to have had any major effects on the human population of South East Asia. It may have emitted enough CO2 to have made a minute difference to the ppm figure had there been anyone around able to measure it.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-09-27T06:30:02.040" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18089" PostTypeId="2" ParentId="18082" CreationDate="2019-09-27T10:19:51.277" Score="1" Body="&lt;p&gt;Solifluction is not restricted to cold climates. Gelifluction on the other hand is, it requires by definition a permanent/seasonal layer of frozen soil. In periglazial environments the porewater above the frozen ground layer becomes easily saturated. Solifluction encompasses numerous processes, Gelifluction is one of them...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The wikipedia page for Solifluction provides more information.&lt;/p&gt;&#xA;" OwnerUserId="17945" LastActivityDate="2019-09-27T10:19:51.277" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18090" PostTypeId="1" CreationDate="2019-09-27T13:53:46.923" Score="1" ViewCount="49" Body="&lt;p&gt;I have 2 cows that go up to a shed and eat grain that I put out every morning, and I also have 5 sheep in the same pasture, that want to eat the grain, so they usually push the cows out of the way, and eat the grain that they dont need. Is there anyway to keeep the sheeps from eating cows grain out of their trough? I've tried raising the trough, but the sheep sut jump up to it and eat.&lt;/p&gt;&#xA;" OwnerUserId="17946" LastActivityDate="2019-09-27T13:53:46.923" Title="How to keep sheep from eating cows grain?" Tags="|agriculture|" AnswerCount="0" CommentCount="2" ClosedDate="2019-09-28T15:33:06.983" ContentLicense="CC BY-SA 4.0" />
  <row Id="18092" PostTypeId="1" CreationDate="2019-09-27T21:43:30.223" Score="3" ViewCount="35" Body="&lt;p&gt;How to interpret lots of gastropoda fossils seen in lacustrine marls? Do they indicate any paleoenvironment conditions? Depth, temperature, chemistry, ph?&lt;/p&gt;&#xA;" OwnerUserId="15195" LastActivityDate="2019-12-15T19:58:13.800" Title="Is there any significance of lacustrine gastropoda fossils regarding paleoenviroment interpretation?" Tags="|sedimentology|paleontology|fossils|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18095" PostTypeId="1" CreationDate="2019-09-28T02:23:48.503" Score="1" ViewCount="246" Body="&lt;p&gt;Why is the outer color of a rainbow red?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NlMTs.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NlMTs.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;sup&gt;(Source: Wikipedia)&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="17954" LastEditorUserId="595" LastEditDate="2019-09-28T15:32:09.203" LastActivityDate="2019-09-28T15:32:09.203" Title="Why is the outer color of a rainbow red?" Tags="|meteorology|" AnswerCount="1" CommentCount="6" ClosedDate="2019-10-08T11:46:07.797" ContentLicense="CC BY-SA 4.0" />
  <row Id="18096" PostTypeId="2" ParentId="18095" CreationDate="2019-09-28T05:25:38.657" Score="1" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Rainbow&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rainbows&lt;/a&gt; are created under certain light conditions when water droplets in the atmosphere act like a &lt;a href=&quot;https://en.wikipedia.org/wiki/Prism&quot; rel=&quot;nofollow noreferrer&quot;&gt;prism&lt;/a&gt; and refract sunlight.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Light is part of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Electromagnetic_spectrum&quot; rel=&quot;nofollow noreferrer&quot;&gt;electromagnetic spectrum&lt;/a&gt; which covers electromagnetic waves from radio waves with a wavelength of 1000 m (long wavelengths) to gamma rays with wavelengths around 0.01 nm (short wavelengths).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sunlight is composed largely of all the colors of the spectrum of visible light. When our eyes see all the colors at once, our brain interprets the color as being &quot;white light&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When humans see a red object that object reflects red light by absorbs all the other colors of light.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the spectrum of visible light, red light has the longest wavelength of 700 nm and violet light has the shortest wavelength of 400 nm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When light enters a water droplet in the atmosphere the water droplet acts like a mini prism. The angle at which the different wavelengths of light exit the prism is determined by &lt;a href=&quot;https://en.wikipedia.org/wiki/Snell%27s_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Snell's Law&lt;/a&gt; and this is why light that exist a prism, or is in a rainbow, is layered into colors with red being the first layer and violet the last.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-09-28T05:25:38.657" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18098" PostTypeId="1" AcceptedAnswerId="18762" CreationDate="2019-09-29T02:03:20.070" Score="2" ViewCount="316" Body="&lt;p&gt;I don't know much about the topic of climate change to be honest. However, I've been attending a number of talks recently on the topic. As someone who studies mathematical models and uncertainty quantification, one thing that I do know is that weather models are extremely complicated and very sensitive to time. The error in weather model accumulated very fast, which makes long term behaviors fuzzy or uncertain. My knowledge is not related to the study on climate much, so that is about all I know.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I read up a bit on the climate issue and understand that the data suggests that climate change is real. I look at the data (from Nasa website) and agree that it supports that claim. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my question is not about whether climate change is real or not. &lt;strong&gt;My question is how some scientists make claims like &quot;in 50 years...&quot;&lt;/strong&gt; My guess is that they observe the trends in history and use that as the basis for their prediction. I hope this question is clear. If you have an understanding on the topic, please point me to the right source.&lt;/p&gt;&#xA;" OwnerUserId="17957" LastEditorUserId="1411" LastEditDate="2019-12-23T12:46:17.170" LastActivityDate="2019-12-23T12:46:17.170" Title="On what basics, can scientists predict the effects of climate change?" Tags="|climate-change|climate|climate-models|" AnswerCount="2" CommentCount="13" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18102" PostTypeId="1" CreationDate="2019-09-30T05:48:10.117" Score="1" ViewCount="40" Body="&lt;p&gt;In the &quot;Plankton cooled a greenhouse&quot;, which is the article written by Birger Schmitz, it is stated that the subtropical regions became warmer during the PETM(Paleocene/Eocene Thermal Maximum) but the temperature elevation was greater in the polar region. (&lt;a href=&quot;https://www.nature.com/articles/35025173&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/35025173&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is evident from the oxygen isotope(18-Oxygen/16-Oxygen) data which can be obtained from the sediments of higher latitudes and lower latitudes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I want to know &lt;strong&gt;why&lt;/strong&gt; the temperature change was greater in higher latitudes than in lower latitudes. This tendency does not seem to be regional, but global so there should be something reasonable to explain this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you come through a good schematic explanation or have a good reference to read, I would obviously want to know it.&lt;/p&gt;&#xA;" OwnerUserId="7329" LastActivityDate="2019-09-30T05:48:10.117" Title="Why was the temperature change greater in higher latitudes than in lower latitudes during the Paleocene/Eocene thermal maximum?" Tags="|geology|oceanography|geochemistry|paleoclimate|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18103" PostTypeId="1" AcceptedAnswerId="18112" CreationDate="2019-09-30T08:05:56.077" Score="1" ViewCount="307" Body="&lt;p&gt;I've been asked this question twice now from our favourite science denying community, and I don't know how to parse it.  I can do centrifugal force and gravity given mass, but have never tried to even see if there should be any deflection of gravity due to centrifugal force at a given latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm guessing I'm being sold a bridge with his numbers, but can't tell for sure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's the numbers he's given me:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Gravitational force (m/s^2) =  9.80576 &lt;/li&gt;&#xA;&lt;li&gt;Latitude (degrees) = 45&lt;/li&gt;&#xA;&lt;li&gt;Velocity (mph) = 735.64 &lt;/li&gt;&#xA;&lt;li&gt;Centrifugal force (m/s^2) = 0.0239809&lt;/li&gt;&#xA;&lt;li&gt;Gravity    Direction Vector = (0.707107, 0.707107)&lt;/li&gt;&#xA;&lt;li&gt;Centrifugal force Direction    Vector = (1, 0)&lt;/li&gt;&#xA;&lt;li&gt;Combined Force = (-6.90974,-6.93372)&lt;/li&gt;&#xA;&lt;li&gt;Combined Force    (relative to ground) = (0.016957,-9.7888)&lt;/li&gt;&#xA;&lt;li&gt;Weight reduction (%)    compared to North pole = 0.172929&lt;/li&gt;&#xA;&lt;li&gt;Projectile drop (time=4.51 seconds)&lt;/li&gt;&#xA;&lt;li&gt;Deflection south (cm) = 17.2454&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Drop height 100 m.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How on Earth do I go about double checking what he's telling me? I'll be attempting to share the answer on YT as a reference for handling this supposed &quot;Gotcha!&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the CF he provides, I'm estimating an object at the surface would have a 712 g mass (from CalcTools), and a 17 cm drift for a 100 m drop for that kind of mass seems like he's off by a factor of 10 (from examples at different lats).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/channel/UCHZ2fjTguMMT0EDGSCcPoEw&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/channel/UCHZ2fjTguMMT0EDGSCcPoEw&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17963" LastEditorUserId="6467" LastEditDate="2019-09-30T23:32:33.790" LastActivityDate="2019-10-01T11:24:15.397" Title="Effects of Centrifugal Force on Gravity Vectors?" Tags="|geophysics|models|planetary-science|" AnswerCount="1" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="18105" PostTypeId="1" CreationDate="2019-09-30T15:30:14.573" Score="9" ViewCount="209" Body="&lt;p&gt;According to &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Carbon_cycle&lt;/a&gt;, organic carbon has a cycle. My question is how does carbon enter the cycle in first place? As far as I can say, inorganic carbon enters the cycle only as CO&lt;sub&gt;2&lt;/sub&gt; that is transformed by photosynthesis.&lt;/p&gt;&#xA;&lt;p&gt;If atmospheric CO&lt;sub&gt;2&lt;/sub&gt; can turn into organic carbon, and, as far as I know, only volcanoes add CO&lt;sub&gt;2&lt;/sub&gt; to the air. So current organic carbon comes from volcanoes or was always part of atmosphere?&lt;/p&gt;&#xA;&lt;p&gt;If that is true, then photosynthetic life has always been constrained to the carbon released by volcanic activity.&lt;/p&gt;&#xA;" OwnerUserId="5004" LastEditorUserId="20607" LastEditDate="2023-02-07T19:47:07.887" LastActivityDate="2023-02-07T19:47:07.887" Title="Is $\ce{CO_2}$ in photosynthesis the only way for carbon to become organic?" Tags="|carbon-cycle|carbon|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18106" PostTypeId="2" ParentId="7212" CreationDate="2019-09-30T17:49:54.117" Score="1" Body="&lt;p&gt;Think about how hot a compost pile can get (hot enough to catch fire). That is basically what is happening at the bottom of the pond over a longer period of time as the decaying matter from the summer decomposes as in a methane digester. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, the ice (and snow) forming around the edges at the top act as an insulator. And since ice floats, it creates a negative feedback cycle in regards to cooling, which is why many lakes freeze on top, but remain liquid below the ice layer (in addition to the biotic heat production).&lt;/p&gt;&#xA;" OwnerUserId="17914" LastActivityDate="2019-09-30T17:49:54.117" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18107" PostTypeId="1" CreationDate="2019-09-30T19:04:23.280" Score="2" ViewCount="50" Body="&lt;p&gt;I collect rocks from the Lehigh Valley River, I have found some many interesting rock. With details that could not be from the water. Can you tell me what would cause the 3 triangle indents on this&#xA;Rock. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/ViKK7.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="17964" LastActivityDate="2019-09-30T19:04:23.280" Title="What would create the triangles in this rock I found in the Lehigh River" Tags="|rocks|" AnswerCount="0" CommentCount="0" FavoriteCount="0" ClosedDate="2019-10-01T09:38:34.170" ContentLicense="CC BY-SA 4.0" />
  <row Id="18108" PostTypeId="1" CreationDate="2019-09-30T19:22:48.903" Score="1" ViewCount="110" Body="&lt;p&gt;I'm looking through historical weather station information from NOAA, and I notice some stations do not have wind speed information but do track Wind Movement(WDMV) over a 24 hour period in kilometers. Would a rough conversion of this to wind speed be: &lt;code&gt;Wind Movement/24 = Wind Speed(km/hr)&lt;/code&gt;, this seems like too basic of a conversion and I realize is not a true average hourly wind speed.&lt;/p&gt;&#xA;" OwnerUserId="17965" LastActivityDate="2019-09-30T22:10:30.473" Title="Converting Wind Movement to Wind Speed" Tags="|meteorology|wind|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18109" PostTypeId="2" ParentId="18108" CreationDate="2019-09-30T22:10:30.473" Score="1" Body="&lt;p&gt;&lt;em&gt;IF&lt;/em&gt; there has been a steady wind direction over that 24 hrs, then yes, this will give you the average wind speed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the wind has changed direction, then there may have been higher speeds that have partially cancelled each other out.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-09-30T22:10:30.473" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18112" PostTypeId="2" ParentId="18103" CreationDate="2019-10-01T10:49:32.363" Score="0" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;I'm guessing I'm being sold a bridge with his numbers, but can't tell for sure.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You're being sold a bridge with his numbers. If he had done the math correctly he would have obtained a deflection of 33.58 cm at 45° geocentric latitude rather than 17.245 cm. The youtube comments show a number of errors. Two key errors are that the commenter assumes that&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Local vertical points directly toward the center of the Earth.&lt;/li&gt;&#xA;&lt;li&gt;Gravitational acceleration due to the Earth's mass points in the same direction.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;What those youtube comments do show is that the Earth is not quite a sphere. A closer approximation is an oblate spheroid. That said, his comments fall into the wronger than wrong category. Quoting Isaac Asimov,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;When people thought the Earth was flat, they were wrong. When people thought the Earth was spherical, they were wrong. But if you think that thinking the Earth is spherical is just as wrong as thinking the Earth is flat, then your view is wronger than both of them put together.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Note that I qualified latitude in the above as geocentric. Geodesists have multiple concepts of latitude. Geocentric latitude is the angle between a line to the center of the Earth and the Earth's equatorial plane. Geodetic latitude is the angle between the normal to the reference ellipsoid and the Earth's equatorial plane. Yet another concept is astronomical latitude, which is the angle between true vertical and the Earth's equatorial plane.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The difference between geocentric and geodetic latitude is at its greatest at 45°. A geocentric latitude of 45° is equivalent to a geodetic latitude of 45° 11' 32.7&quot;. Converting that 11' 32.7&quot; difference to radians and multiplying by 100 meters results in 33.58 cm. The difference between geodetic and astronomical latitude is called the deflection of the vertical (or vertical deflection). The deflection of the vertical is rather small, less than 2' (two minutes of arc) even in extremely mountainous terrain. Typical values are a few tens of arc seconds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What this means is that an oblate spheroid is a better model of the Earth's shape than a sphere. That does not mean a flat Earth model is correct. The Earth's flattening (how squished the Earth is at the poles versus the at the equator) is rather small. The poles are 22 km closer to the center of the Earth than is the equator. Percentage-wise, that's a 0.345% difference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason an oblate spheroid is a better model of the Earth's shape than a sphere is because the Earth is spinning. That spin does two things: It results in a centrifugal acceleration from the perspective of an observer fixed with respect to the rotating Earth, and it results in an equatorial bulge. If the Earth was a uniform density liquid, the spin would make the Earth naturally relax into an oblate spheroidal shape. &quot;Straight down&quot;, the combined effects of gravitational and centrifugal acceleration (geodesists call this &quot;gravity&quot; to distinguish it from gravitation) would be exactly normal to the surface.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2019-10-01T11:24:15.397" LastActivityDate="2019-10-01T11:24:15.397" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18113" PostTypeId="1" CreationDate="2019-10-01T14:11:24.163" Score="1" ViewCount="119" Body="&lt;p&gt;Since Complex EOF (CEOF) is doing hilbert transform before general EOF,&#xA;we can get four outputs in each mode.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Magnitude spatial pattern&lt;/li&gt;&#xA;&lt;li&gt;Magnitude time series &lt;/li&gt;&#xA;&lt;li&gt;Phase spatial pattern&lt;/li&gt;&#xA;&lt;li&gt;Phase time series&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I would like to ask that the spatial pattern in Magnitude and Phase are corresponding to &quot;Phase velocity&quot; or &quot;Group velocity&quot; ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;" OwnerUserId="13265" LastActivityDate="2019-10-01T14:11:24.163" Title="Complex Empirical Orthogonal Function analysis on Propagating wave" Tags="|waves|data-analysis|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18114" PostTypeId="1" CreationDate="2019-10-01T16:05:54.027" Score="1" ViewCount="27" Body="&lt;p&gt;In a &lt;a href=&quot;https://skeptics.stackexchange.com/a/45056/29579&quot;&gt;self-answer&lt;/a&gt; of mine on Skeptics, one of the comments rightly pointed out that the model in question (from Impact Lab) does not explicitly account for mortality due to sea level changes. Are there such models published which model mortality changes due to sea level changes? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Also is there a tag here for economic or social aspects of climate change or earth sciences other than geology?)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And I don't mean &lt;a href=&quot;https://doi.org/10.1016/j.marpolbul.2014.03.058&quot; rel=&quot;nofollow noreferrer&quot;&gt;coral mortality&lt;/a&gt; (or other animals), but human...&lt;/p&gt;&#xA;" OwnerUserId="11964" LastEditorUserId="11964" LastEditDate="2019-10-01T16:14:15.643" LastActivityDate="2019-10-01T16:14:15.643" Title="Are there models of mortality due to sea level increases (via climate change)?" Tags="|climate-change|sea-level|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18116" PostTypeId="2" ParentId="18086" CreationDate="2019-10-01T23:18:15.983" Score="2" Body="&lt;p&gt;I'm not well studied in this field, but I suspect that global average temperature by proxy for a single year is difficult to measure accurately.  The 1991 cooling from Mt. Pinatubo happened recently enough that accurate measurements were made, though cooling is still somewhat difficult to pin down exactly due to other variation factors, sunspots being a small variation and the Pacific current being a big variation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1990, at the time, &lt;a href=&quot;https://www.latimes.com/archives/la-xpm-1991-01-10-mn-11310-story.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;was the hottest year on record&lt;/a&gt;, driven in part by the El Nino that year.  (El Nino warms the Earth and usually lasts for a year, maybe 18 months or 2 years sometimes).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/096706459500041N&quot; rel=&quot;nofollow noreferrer&quot;&gt;The El Nino continued into 1991&lt;/a&gt;, though it weakened greatly by the end of 1991 (Peak El Nino being about 12 months is about right).  And the Mt. Pinatubo eruption happened on June 15, so it didn't affect climate in 1991 until nearly half way through the year.    1991 might have been warmer than 1990 prior to the eruption (I looked for a source on the first half of 1991 but couldn't find it).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Overall, 1991 was colder than 1990 but only a little, and probably would have been warmer without Pinatubo.  1992 was considerably colder than 1993 and 1994 showed gradual warming and 1995 set a new hottest year on record at the time.   The fall 1990 to 1991 was likely volcano driven but the bigger fall in 1992 was probably partially driven by the weakening El Nino.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ncdc.noaa.gov/sotc/global/201113&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chart used as source if you scroll down&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/096706459500041N&quot; rel=&quot;nofollow noreferrer&quot;&gt;The article above - see quote&lt;/a&gt; says that Pinatubo lowered temperatures less than your source suggests.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;in the year to follow, volcanic particles in the atmosphere would&#xA;  lower global temperatures by an average of 0.9 degrees Fahrenheit (0.5&#xA;  degrees Celsius).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But, something to keep in mind about a 0.5 degree drop is that oceans are very slow to react, and unlike land, oceans don't warm up well under direct sunlight due to evaporation and the cooling effect of photon-generated evaporation.  Because Earth is about 70% covered by ocean nearly all that 0.5 degree variation is over the land, land surface temperatures drop by nearly 1.5 degrees C and Oceans change very little.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, and this is important, volcanic &quot;winters&quot; aren't just about temperature drop but also about sunlight blocking.   Less sunlight means less crop growth and it only takes one frost at the wrong time to kill a lot of crops, so even if a 1 or 2 degree Celsius drop or, lets say 2-3 degree drop over land that might not sound devastating, but temperature drops like that can be associated with a considerably higher chance of frost and crop-death.  The 1991 eruption wasn't associated with crop failures, &lt;a href=&quot;https://stevenmcollins.com/a-global-food-shortage-could-occur-quickly/&quot; rel=&quot;nofollow noreferrer&quot;&gt;but the 1883 and 1815 eruptions were&lt;/a&gt;.  Sunlight blocking may have been as big or an even bigger factor as temperature drop, but late frosts may have played a key role as well.   (I lack the knowledge to give precise data on this).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I realize I've not answered your question with a number like you asked.   You can find estimates of temperature drop in various articles, usually about 1-2 degrees from big volcanic eruptions like the one in 1815, but neither the 1883 nor the 1815 were accurately measured.  From what I gather (but I haven't found it said specifically), the 1883 cold spell lead to greater interest in global temperature, which is why many global average temperature charts begin in 1884, after Krakatoa.   We may not have an accurate estimate on the temperature drop from a super-volcano.  Narrowing down an accurate estimate based on geological evidence for one year, even supported with some local temperatures and historical records is tricky.   I don't think anyone knows the specifics of temperature drop by super-volcano with accuracy. The numbers that get reported are probably somewhere between guesses and estimates. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, not all eruptions are alike.   A higher SO2 content should create a longer cooling.   Volcanoes vary in sulfur content. &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2019-10-01T23:18:15.983" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18117" PostTypeId="1" CreationDate="2019-10-02T05:19:30.560" Score="4" ViewCount="519" Body="&lt;p&gt;When groundwater is pumped out of the ground by wells, and not replenished fast enough, the groundwater level sinks. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With it, the surface of the area sinks also. Locally, this effect is not apparent, because heights of objects are specified relative to the surface. The change in height stays zero by definition. But relative to the average elevation of surrounding land not connected in terms of ground water, there is a change. What changes is the distance between soil surface and center of gravity of the earth. The subsidence is a change in the shape of the earth, so its center of gravity changes itself, but the magnitude of that change is small enough compared to the surface change to ignore it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can the change in surface elevation of a fixed point on the surface of the Earth be measured?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One approach would be to use the fact that the surface of a water volume in equilibrium is the same height everywhere, even if the surface is separated. The water level in both ends of a U-shaped pipe is the same. One could use a long pipe that reaches from the measured location to a reference point. Connected bodies of groundwater are large, so that may require pipes of a length in the order of kilometers. Also, with a large distance between the end the air pressure may be different, so there is no equilibrium. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ground water level itself is a possible reference point, because the ground water can permeate the ground. But we know that it is not in equilibrium, because ground water is removed only in parts of the surface - the wells, and the permeation is slow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ground elevation can be measured from satellites, as GPS does. I suspect that the accuracy is too low for many purposes because the relative change in the measured distance is very small. Also, the orbit of a satellite changes with the change of the center of gravity. Because the change is slow, elevation changes in distant regions influencing the satellite create noise in the measurement.&lt;/p&gt;&#xA;" OwnerUserId="321" LastEditorUserId="321" LastEditDate="2019-10-02T19:15:28.293" LastActivityDate="2022-01-26T01:38:13.650" Title="How is land subsidence measured?" Tags="|measurements|groundwater|field-measurements|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18118" PostTypeId="1" CreationDate="2019-10-02T10:39:25.223" Score="1" ViewCount="159" Body="&lt;p&gt;We have two traveltive curves for first arrivals (direct and refracted) from a dipping refractor in the forward and reverse directions along a profile line.&#xA;my question is:&#xA;Is there a logical way (non-descriptive) to determine the actual dip and the dip direction of the refractor?&#xA;I have already done the computations for velocity V1=2000 m/s, apparent velocities V2=2820 m/s, V2'=7690 m/s, dip φ=-15 degrees and critical angle ic=37,6 degrees.&lt;a href=&quot;https://i.stack.imgur.com/uM2sZ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uM2sZ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17782" LastEditorUserId="39" LastEditDate="2019-10-02T16:59:02.733" LastActivityDate="2019-10-02T16:59:02.733" Title="Finding out actual dip and dip direction of refractor" Tags="|geophysics|seismic|homework|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18119" PostTypeId="2" ParentId="18117" CreationDate="2019-10-02T11:47:18.143" Score="2" Body="&lt;p&gt;Land that has been heavily disturbed by humans in most developed countries, such as urban and rural regions will have been surveyed for topographical &amp;amp; sub-division purposes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Such data allows for a digital terrain model (DTM) to be created for such regions. When subsidence occurs, the subsided area can be resurveyed &amp;amp; compared to the original DTM to ascertain the amount of subsidence that has occurred.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Undisturbed or poorly surveyed regions become problematic. The subsidence area &amp;amp; the surrounding area can be surveyed, but then someone has to make a judgement call &amp;amp; decide what the original surface may have looked like to infer an estimate for the degree of subsidence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other way is to have satellites periodically measure surface elevations &amp;amp; then to do comparisons between each satellite measurement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Radar could be used as the measuring system, but &lt;a href=&quot;https://en.wikipedia.org/wiki/Lidar&quot; rel=&quot;nofollow noreferrer&quot;&gt;LIDAR&lt;/a&gt; (&amp;amp; &lt;a href=&quot;https://oceanservice.noaa.gov/facts/lidar.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this reference also&lt;/a&gt;) can produce more accurate results. &lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-10-02T11:47:18.143" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18120" PostTypeId="2" ParentId="18117" CreationDate="2019-10-02T16:58:43.500" Score="0" Body="&lt;p&gt;In part, this is a geodesy question. I'm not an expert in that area, but there are experts on this site, so perhaps they'll come along. But I want to focus on one thing in the question:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;heights of objects are measured relative to the surface&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;They don't have to be. Heights of objects are measured relative to some vertical datum. That might be the local ground level (but as the question notes, if what you are measuring is local ground level than that's clearly not useful). They might be measured compared to some datum representing sea level. Or they might be measured compared to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Geoid&quot; rel=&quot;nofollow noreferrer&quot;&gt;geoid&lt;/a&gt;, or some &lt;a href=&quot;http://en.wikipedia.org/wiki/Reference_ellipsoid&quot; rel=&quot;nofollow noreferrer&quot;&gt;reference ellipsoid&lt;/a&gt;. The last of these is what is happening when you use GPS measurements.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-10-02T16:58:43.500" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18121" PostTypeId="1" CreationDate="2019-10-03T01:05:20.263" Score="7" ViewCount="182" Body="&lt;p&gt;Earth famously possesses three distinct &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_circulation&quot; rel=&quot;nofollow noreferrer&quot;&gt;circulation cells&lt;/a&gt; per hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now out of curiosity one could use a weather app, like windy, to display the wind structures at ground level globally, and the supposed return winds at around 250 hPa height.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I do that, the picture is very messy and I cannot see any clear circulation cells.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suppose, that all the other messy physics of the Earths atmosphere will overlap with the cells, but &lt;strong&gt;is there a time in the year or variable I can use to see the circulation cells in wind maps?&lt;/strong&gt;&lt;br&gt;&#xA;Or are they in the end just an idealised time-average, that we use to model the winds / (trade winds, famously..) and don't exist at any given time?&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorDisplayName="user1066" LastEditDate="2019-10-09T04:13:54.080" LastActivityDate="2021-03-01T12:11:28.573" Title="Can we see the circulation cells in wind maps?" Tags="|meteorology|climatology|atmospheric-circulation|" AnswerCount="1" CommentCount="6" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18124" PostTypeId="1" CreationDate="2019-10-03T10:52:02.527" Score="1" ViewCount="81" Body="&lt;p&gt;Will &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_tax&quot; rel=&quot;nofollow noreferrer&quot;&gt;Carbon tax&lt;/a&gt; be applied to other emissions or only carbon emissions like Carbon dioxide &amp;amp; Carbon monoxide ? Can non-warming pollutant emissions like &lt;a href=&quot;https://en.wikipedia.org/wiki/Chaff_(countermeasure)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chaff&lt;/a&gt;(Chemtrail) also be taxed under the Carbon tax ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For reference, see &lt;a href=&quot;https://earthscience.stackexchange.com/questions/12902/why-is-carbon-pollution-given-more-importance-than-sulfur-pollution-or-nitrogen&quot;&gt;Why is carbon pollution given more importance than Sulfur pollution or Nitrogen pollution ?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11793" LastActivityDate="2019-10-03T21:15:08.050" Title="Will carbon tax be applicable to other emissions?" Tags="|climate-change|co2|pollution|" AnswerCount="1" CommentCount="5" ClosedDate="2019-10-04T15:16:40.600" ContentLicense="CC BY-SA 4.0" />
  <row Id="18126" PostTypeId="1" AcceptedAnswerId="18127" CreationDate="2019-10-03T12:45:16.700" Score="1" ViewCount="142" Body="&lt;p&gt;How much water does a typical aquifer contain, and is casual well use is likely to deplete them?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your answer can take many forms, but an ideal question would cover these sort of areas- would a single well that someone took 50 liters from a day deplete one? Do you need industrial use of hundreds of meters cubed? Typically how vulnerable are they to depletion by people. Is there a lot of variability in size, or are they usually fairly large? Does it take months, years, decades?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Inspired by Mad Max, where there is a large mountain aquifer supplying a couple hundred people and I have no idea how long it would take to deplete.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Previous questions have covered this in vague terms but haven't given a general picture of what it's like for people in general, especially in more remote areas where they may not have access to the largest of aquifers, which apparently can last decades. I'm more curious what it's like for a random farmer.&lt;/p&gt;&#xA;" OwnerUserId="17981" LastEditorUserId="17981" LastEditDate="2019-10-03T12:57:05.663" LastActivityDate="2019-10-03T14:29:44.837" Title="How much water do aquifers contain? How much does it take to deplete them?" Tags="|human-influence|water-table|underground-water|watershed|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18127" PostTypeId="2" ParentId="18126" CreationDate="2019-10-03T13:23:23.723" Score="1" Body="&lt;p&gt;It depends on the size of the aquifer and the amount of precipitation falling on the exposed areas of the aquifer. These have been used to provide water form many major cities.&lt;br&gt;&lt;br&gt;&#xA;The Trafalgar square fountains were initially powered by artesian pressure (as London is below the altitude of the North downs / Chilterns). Eventully too much water was extracted leading to salt water incursions in places. This aquifer is still in use but backed up by a number of surface reservoirs surrounding the London area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;i&gt;&quot;&#xA;The Report of the Royal Commission on Water Supply (1869) shows that, by 1869, a number of large conurbations were supplied by groundwater. Nottingham and parts of Liverpool and Birkenhead relied on wells in the Permo-Triassic sandstones, Sunderland and South Shields on the Permian Magnesian Limestone and Croydon and parts of south east London on the Chalk. Government offices around Westminster together with the fountains in Trafalgar Square were supplied by wells sunk to the Chalk in 1844 (Amos, 1860).&#xA;&quot;&lt;/i&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More from here &lt;a href=&quot;http://www.groundwateruk.org/British-Hydrogeology-a-brief-history.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.groundwateruk.org/British-Hydrogeology-a-brief-history.aspx&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More detail on the London aquifer:&#xA; &lt;a href=&quot;https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/735451/2018_Final.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/735451/2018_Final.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17751" LastEditorUserId="17751" LastEditDate="2019-10-03T14:29:44.837" LastActivityDate="2019-10-03T14:29:44.837" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18128" PostTypeId="1" AcceptedAnswerId="18137" CreationDate="2019-10-03T17:42:24.737" Score="1" ViewCount="11119" Body="&lt;p&gt;It's relatively well known that Everest is the &lt;em&gt;highest&lt;/em&gt; mountain above sea level, and that Mauna Kea in Hawaii is the &lt;em&gt;tallest&lt;/em&gt; mountain from base to top.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But how tall is Everest from base to top? Or to put it another way, how high is Everest's base?&lt;/p&gt;&#xA;" OwnerUserId="12740" LastActivityDate="2019-10-04T16:55:09.407" Title="Height of Everest from base to top" Tags="|geology|mountains|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18130" PostTypeId="2" ParentId="18124" CreationDate="2019-10-03T21:06:23.437" Score="2" Body="&lt;p&gt;The recent &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_pricing_in_Canada&quot; rel=&quot;nofollow noreferrer&quot;&gt;Canadian carbon tax law is just CO2&lt;/a&gt;.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;CO, which you asked about, is bad for people and considered a pollutant.   Efforts to reduce CO have been underway for decades including carbon monoxide detectors in homes and garages and catalytic converters in cars.  The target behind CO is elimination as much as possible.   Being a pollutant, there's a different approach.  The tax is only meant to discourage CO2 production, which isn't a pollutant, but it is a problem due to gradual build up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Likewise, sulfur pollution, coal being a primary source, is dealt with by strict limits (in the US), and scrubbers which catch sulfur emissions have been installed in coal plants since the 1980s. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additional greenhouse gas taxes like CH4 might eventually come to pass, but, like CO, the effort with the greehouse gas CH4 should be elimination, not taxation.  It's also harder to put a number on CH4 released, which can be released by fracking seepage or cow burps primarily or by escape from thawing tundra (are we going to tax teh ground?).    CO2 is easier, for example because we know how much CO2 is produced per gallon of gasoline, for example, so a tax is straight forward, but cow burps or fracking seepage could be estimated so a tax there might be possible.      &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the general idea, is that, if it's preventable and a pollutant of some form, then regulation should aspire to reduce output, even strive towards elimination.   CO2 is an inevitable byproduct of burning fossil fuels, so it can't be eliminated and it would be problematic to try, but it can be financially discouraged by taxation.   &lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="2717" LastEditDate="2019-10-03T21:15:08.050" LastActivityDate="2019-10-03T21:15:08.050" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18131" PostTypeId="1" AcceptedAnswerId="18133" CreationDate="2019-10-04T00:22:29.117" Score="8" ViewCount="988" Body="&lt;p&gt;Someone I know posted a question about climate change that I do not know how to answer. While I do believe (for lack of better word) in climate change, I do not know how to answer this persons question. The tl;dr of the question is:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If climate change is not a natural phenomenon, then how did the last&#xA;  ice age end?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The person is implying that warming/cooling reoccurs periodically on the Earth, and that the current climate change threat is overblown.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have searched online for answers, but cannot find anything concise on this specific subject. According to this &lt;a href=&quot;https://en.wikipedia.org/wiki/Ice_age#Causes&quot; rel=&quot;noreferrer&quot;&gt;wikipedia article&lt;/a&gt;, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;There is evidence that greenhouse gas levels fell at the start of ice&#xA;  ages and rose during the retreat of the ice sheets, but it is&#xA;  difficult to establish cause and effect (see the notes above on the&#xA;  role of weathering). Greenhouse gas levels may also have been affected&#xA;  by other factors which have been proposed as causes of ice ages, such&#xA;  as the movement of continents and volcanism.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In short, how and why did the last ice ages end? I am assuming that the carbon dioxide concentration during these ice ages is much lower than the &lt;a href=&quot;https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide&quot; rel=&quot;noreferrer&quot;&gt;current estimate of ~410 ppm&lt;/a&gt;. Aside from the difference in carbon dioxide levels, what evidence suggests that the climate change of today is different than the climate change that ended the ice age(s)?&lt;/p&gt;&#xA;" OwnerDisplayName="user14859" LastActivityDate="2023-06-21T22:22:57.587" Title="How is climate change today different than the climate change that ended the ice age(s)?" Tags="|climate-change|volcanology|ice-age|natural-disasters|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18132" PostTypeId="2" ParentId="18131" CreationDate="2019-10-04T02:28:21.570" Score="1" Body="&lt;p&gt;There is a major difference.  The climate changes that caused the end of the last Ice Age (and the start/end of previous ones) were basically the result of changes in the Earth's orbital eccentricity and axial tilt.  These changes are called the Milankovich Cycles, and you can read more about them here: &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Milankovitch_cycles&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The current global warming that is often called &quot;climate change&quot; is the result of humans burning fossil fuels.  This adds more CO2 to the atmosphere.  The addition is measured, e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Keeling_Curve&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Keeling_Curve&lt;/a&gt; and correlates well to the amount of coal, oil, and natural gas burned.  That atmospheric CO2 traps solar radiation*, causing the Earth to warm up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*OK, it's a little more complex than that.  What happens is that the solar radiation (light) passes through the atmosphere and warms the ground.  The warm ground emits infrared radiation, which the CO2 blocks.  It's rather like putting on an extra sweater when you're cold.  If you want a detailed explanation, Weart's &quot;The Discovery of Global Warming&quot; is a good on-line introduction: &lt;a href=&quot;https://history.aip.org/climate/index.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://history.aip.org/climate/index.htm&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2019-10-04T02:28:21.570" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18133" PostTypeId="2" ParentId="18131" CreationDate="2019-10-04T08:57:59.370" Score="7" Body="&lt;p&gt;Difference #1: &lt;strong&gt;Speed&lt;/strong&gt;. The warming at the end of the ice ages went much, much slower than what we are currently experiencing.&lt;/p&gt;&#xA;&lt;p&gt;Estimates of the amount of warming since the beginning of the industrial revolution are &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/sites/2/2018/12/SR15_FAQ_Low_Res.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;in the order or 1 degree Celsius&lt;/a&gt;&lt;sup&gt;*&lt;/sup&gt; - that's in 100-150 years time.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;* Page 7&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;When the Earth moved out of ice ages over the past million years, the global temperature rose a total of 4 to 7 degrees Celsius over about 5,000 years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;sup&gt;(NASA Source: &lt;a href=&quot;https://earthobservatory.nasa.gov/features/GlobalWarming/page3.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;How is Today’s Warming Different from the Past?&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;The article &lt;a href=&quot;https://www.theguardian.com/environment/climate-consensus-97-per-cent/2016/feb/24/earth-is-warming-is-50x-faster-than-when-it-comes-out-of-an-ice-age&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth is warming 50x faster than when it comes out of an ice age&lt;/a&gt; sums it up nicely:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;What humans are in the process of doing to the climate makes the transition out of the last ice age look like a casual stroll through the park. We’re already warming the Earth about 20 times faster than during the ice age transition, and over the next century that rate could increase to 50 times faster or more. We’re in the process of destabilizing the global climate far more quickly than happens even in some of the most severe natural climate change events.&lt;/p&gt;&#xA;&lt;p&gt;That rapid climate destabilization is what has climate scientists worried. It’s faster than many species can adapt to, and could therefore cause widespread extinctions, among other dangerous climate change consequences. Coastal flooding in places like Florida has already become much more common than it was just 50 years ago, and sea level rise is expected to keep accelerating.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Difference #2: &lt;strong&gt;Civilization&lt;/strong&gt;. At the end of the ice ages we did not have &lt;a href=&quot;https://www.prb.org/rippleeffectspopulationandcoastalregions/&quot; rel=&quot;nofollow noreferrer&quot;&gt;3 billion people living within 200 km from a coast line&lt;/a&gt;&lt;br /&gt;&#xA;That is not an difference in the &lt;em&gt;cause&lt;/em&gt; of the warming, but definitely in the &lt;em&gt;effect&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;One could argue that that same civilization will make us able to deal with the consequences, but looking at thing that already exists several centuries without change, surely raises doubts to our ability to deal with the current rate of climate change. Think (1) unequal global wealth distribution or (2) the psychology of our behavior (denial, politics).&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;BTW The question asked to you&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;If climate change is not a natural phenomenon, then how did the last ice age end?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;is based on a false premise - it's a bit of a word game.&lt;br /&gt;&#xA;The current warming is &lt;em&gt;still&lt;/em&gt; a natural phenomenon, but it's now &lt;a href=&quot;https://www.britannica.com/science/climate-change/Evidence-for-climate-change&quot; rel=&quot;nofollow noreferrer&quot;&gt;primarily driven by &lt;em&gt;our&lt;/em&gt; input, and not other 'natural' phenomena&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="595" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-10-04T09:20:24.357" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18134" PostTypeId="1" AcceptedAnswerId="18139" CreationDate="2019-10-04T15:50:15.183" Score="2" ViewCount="201" Body="&lt;p&gt;I encounter both similar terms while reading, isotherms and isotheres. Could someone help distinguish and explain to me the difference between them?&lt;/p&gt;&#xA;" OwnerUserId="4688" LastActivityDate="2019-11-03T21:01:05.143" Title="Difference between isotherms and isotheres" Tags="|temperature|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18135" PostTypeId="2" ParentId="18128" CreationDate="2019-10-04T16:24:03.333" Score="1" Body="&lt;p&gt;The 1954 recorded height of 8,848 m remains the accepted figure for height. As for the elevation of Everest's base, it is 5,380 m (at 17,600 ft). &lt;/p&gt;&#xA;" OwnerUserId="4688" LastActivityDate="2019-10-04T16:24:03.333" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18136" PostTypeId="1" AcceptedAnswerId="18614" CreationDate="2019-10-04T16:25:55.450" Score="11" ViewCount="297" Body="&lt;p&gt;We hear a lot about positive feedbacks when it comes to global warming. For example: ice reflects solar radiation, so as the ice melts more solar radiation is absorbed which accelerates warming; rising temperatures create more deserts; release of stored methane; water-vapour feedback; etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With so many positive feedbacks it would seem that once the earth has flipped out of an ice age it would take an absolutely tremendous amount of change to get us back into one. Yet the explanations given for the onset and offset of ice ages (subtle orbital variations, continental movements) do not seem that great.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So how can these subtle changes ever be enough to flip us back into an ice age? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do we have long time span climate-models to validate our theories?&lt;/p&gt;&#xA;" OwnerUserId="17987" LastEditorUserId="6258" LastEditDate="2019-10-08T04:45:10.557" LastActivityDate="2019-12-02T19:37:53.397" Title="With so many positive feedbacks accelerating global warming, how did the earth ever re-enter ice ages after it came out of one?" Tags="|climate-change|earth-history|climate-models|ice-age|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18137" PostTypeId="2" ParentId="18128" CreationDate="2019-10-04T16:55:09.407" Score="1" Body="&lt;p&gt;The height of Everest above its base depends on where one considers its base to be - and this depends on which side of the mountain one looks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Everest&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;reasonable base elevations for Everest range from 4,200 m (13,800 ft)&#xA;  on the south side to 5,200 m (17,100 ft) on the Tibetan Plateau,&#xA;  yielding a height above base in the range of 3,650 to 4,650 m (11,980&#xA;  to 15,260 ft).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-10-04T16:55:09.407" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18138" PostTypeId="2" ParentId="18067" CreationDate="2019-10-04T19:02:03.590" Score="0" Body="&lt;p&gt;As far as working with netCDF files is concerned, you can use &lt;a href=&quot;https://unidata.github.io/netcdf4-python/netCDF4/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this example&lt;/a&gt;. What I've done in the past is loop through the dimensions, variables, and file attributes, with if statements to make changes to the parts of the file that I want to edit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In your case, you can do what you think is best. Perhaps you can just take an average of the emissions to smooth over the subgrid variability between the wrfchemi grid and the shapefile. Just make sure that the units are consistent. Concerning temporal variability, you can do what you think is appropriate, just specify what you do when communicating your methods. So if it is easier for you to just input constant hourly emissions from a daily average emissions, then do that. If you think it is easier to keep the hour-by-hour pattern, then you can do that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as the speciation is concerned (see &lt;a href=&quot;https://ruc.noaa.gov/wrf/wrf-chem/Emission_guide.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;pages 14-15&lt;/a&gt;), you can put PM10 in the e_pm10 variable. The PM2.5 emissions is up to you, though keep in mind what the difference between these two are (see &lt;a href=&quot;https://www.narsto.org/sites/narsto-dev.ornl.gov/files/Ch3813KB.pdF&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; and &lt;a href=&quot;https://aerosol.ees.ufl.edu/atmos_aerosol/section04-2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2019-10-04T19:02:03.590" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18139" PostTypeId="2" ParentId="18134" CreationDate="2019-10-04T20:41:20.287" Score="2" Body="&lt;p&gt;&lt;strong&gt;The general term &lt;em&gt;isotherm&lt;/em&gt; refers to a &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Isotherm&quot; rel=&quot;nofollow noreferrer&quot;&gt;line of equal or constant temperature&lt;/a&gt;, while &lt;em&gt;isothere&lt;/em&gt; refers more specifically to &lt;a href=&quot;https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1256/wea.33.06&quot; rel=&quot;nofollow noreferrer&quot;&gt;lines of constant average summer temperature&lt;/a&gt;.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For what it's worth, coming from a background in forecasting and research centered around active weather rather than longer-term climate, &lt;em&gt;isotherm&lt;/em&gt; is an extremely commonly-used term in weather discussions but I can't recall ever seeing &lt;em&gt;isothere&lt;/em&gt; used in practice before now. &lt;/p&gt;&#xA;" OwnerUserId="14078" LastActivityDate="2019-10-04T20:41:20.287" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18140" PostTypeId="1" AcceptedAnswerId="18152" CreationDate="2019-10-05T03:14:03.560" Score="2" ViewCount="53" Body="&lt;p&gt;So there's a NASA satellite called SMAP currently orbiting Earth right now, and it can measure soil moisture, and detect whether or not soil is frozen or thawed. It knows this since it uses radar to detect natural microwave emissions from the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But what are natural microwave emissions, and what tools are necessary to detect and process the information (doesn't have to be related to NASA)?&lt;/p&gt;&#xA;" OwnerDisplayName="user17688" LastActivityDate="2019-10-06T19:27:41.100" Title="How does SMAP detect soil statistics?" Tags="|soil-moisture|radar|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18141" PostTypeId="1" CreationDate="2019-10-05T03:14:24.537" Score="1" ViewCount="271" Body="&lt;p&gt;&quot;Based on the best historical data that we have available CO2 is probably increasing at a rate at of least 100 times faster than at any time in the last 800,000 years.&quot; Pieter Tans lead scientist of NOAA's Global Greenhouse Gas Reference Network.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Peter Tans approved the above verbatim quote to be directly attributed to him. I contacted him by email today on the basis of this material:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;“The rate of CO2 growth over the last decade is 100 to 200 times faster than what the Earth experienced during the transition from the last Ice Age,” Pieter Tans, lead scientist of NOAA’s Global Greenhouse Gas Reference Network, said in a statement. “This is a real shock to the atmosphere.”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The annual rate of increase in atmospheric carbon dioxide over the past 60 years is about 100 times faster than previous natural increases, such as those that occurred at the end of the last ice age 11,000-17,000 years ago.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://e360.yale.edu/digest/co2-levels-continue-to-increase-at-record-rate&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://e360.yale.edu/digest/co2-levels-continue-to-increase-at-record-rate&lt;/a&gt; &#xA;&lt;a href=&quot;https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/L7cv8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/L7cv8.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17970" LastEditorUserId="17970" LastEditDate="2019-10-08T04:45:33.843" LastActivityDate="2019-10-08T04:45:33.843" Title="Is there any natural phenomenon that can account for the 100 fold faster CO2 rate increase?" Tags="|climate-change|climate-models|paleoclimatology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18142" PostTypeId="1" CreationDate="2019-10-05T17:32:23.500" Score="1" ViewCount="126" Body="&lt;p&gt;When you’re in the mountains for example like in the Appalachian Mountains, is thunder heard more easily from further away in the mountains rather than if you aren’t in the mountains?&lt;/p&gt;&#xA;" OwnerUserId="17923" LastActivityDate="2020-11-13T03:06:25.623" Title="Thunderstorms in Mountains" Tags="|mountains|thunderstorm|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18143" PostTypeId="2" ParentId="18142" CreationDate="2019-10-05T20:17:06.307" Score="1" Body="&lt;p&gt;I presume you mean if one were a substantial distance away from a lightning strike in the mountains, would it be heard better or worse by another observer the same distance away in the plains and foothills? It depends whereabouts in the mountains this lightning strike occurs and where the observers or listeners are. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If it occurred between two rocky ridges forming a V shape with the open end directed toward the plain, it is likely that the observer on the plain would hear it more clearly than an observer or listener the same distance away in the mountains. The very mountain walls which reflected the sound toward the plain would act as barriers to listeners placed, let's say, 10 miles away in the mountains to either side. This is called acoustics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One can also imagine an acoustic layout in which the mountain observer would hear the strike more clearly and loudly, but on balance the plains observer would be more often in a position to hear the thunder clearly. My own observations of thunder in the mountains and coastal areas of Brunei and Sarawak would seem to bear that out&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-10-05T20:17:06.307" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18144" PostTypeId="1" CreationDate="2019-10-05T21:53:31.427" Score="1" ViewCount="72" Body="&lt;p&gt;Pieter Tans 2019-10-07&lt;br&gt;(lead scientist of NOAA's Global Greenhouse Gas Reference Network):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Based on the best historical data that we have available CO2 is probably increasing at a rate at of least 100 times faster than at any time in the last 800,000 years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I want to make sure that this is an accurate statement.&lt;br /&gt;&#xA;&lt;strong&gt;Have there been any faster changes over a similar timespan in the history of life?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Does science validate this statement: &quot;It is virtually certain that there are no natural processes that could plausibly account for an average annual CO2 increase of 1.42 PPM lasting 70 years (1950 to present) at any time in the last 40 million years&quot;&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Here is the 40 million year data graph&lt;/strong&gt;&lt;br&gt;&#xA;&lt;a href=&quot;https://royalsocietypublishing.org/cms/attachment/1821253f-a0d4-48a5-a7a2-417797ca775e/rsta20130096f05.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://royalsocietypublishing.org/cms/attachment/1821253f-a0d4-48a5-a7a2-417797ca775e/rsta20130096f05.jpg&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5rA8K.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5rA8K.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17970" LastEditorUserId="17970" LastEditDate="2019-10-08T17:57:55.027" LastActivityDate="2019-10-08T17:57:55.027" Title="Does anyone have any data indicating a faster rate of CO2 increase?" Tags="|climate-change|paleoclimatology|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18145" PostTypeId="1" CreationDate="2019-10-05T22:17:13.340" Score="1" ViewCount="208" Body="&lt;p&gt;Usually the higher the humidity the more rainfall we get like in the summer here in Asheville, North Carolina we get a lot of showers and thunderstorms in the summer from the high humidity but I saw that in April is when humidity is at its lowest. How is that possible because we get lots of rain showers in April here in Asheville so how can humidity be at its lowest?&lt;/p&gt;&#xA;" OwnerUserId="17923" LastActivityDate="2019-11-06T01:00:50.080" Title="Humidity and Rainfall" Tags="|rainfall|humidity|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18146" PostTypeId="2" ParentId="18145" CreationDate="2019-10-06T02:32:46.720" Score="1" Body="&lt;p&gt;Now you see, humidity and rainfall are connected, but not in the way that you'd expect...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's suppose that their are rain clouds already in the air, maybe a couple hundred meters to a kilometer or so. Now imagine two scenarios:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Humidity of the air is low&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Humidity of the air is high&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oh, and there is one more thing you need to understand before we move on. As raindrops fall, some of the water will evaporate into the atmosphere, increasing the humidity; but the air can only absorb the water if it has low humidity. Okay, back to our example.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Humidity of the air is low&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Air can absorb a lot of water&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;As the rain drops fall, most, if not all of the water will be absorbed (evaporated) in the surrounding air&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;2) Humidity of the air is high&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Air can absorb little to no water&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;As raindrops fall, the water will not be absorbed into the air&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The second example is called rain. The first example is called &lt;em&gt;virga&lt;/em&gt;. And yes, when virga happens, some of the rain drops don't even reach the ground! Crazy, right?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But now to answer your question...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm assuming that your clouds are relatively low to the ground, maybe no more than a kilometer. Also in April, the sun isn't that strong, so it doesn't have a chance to evaporate that much water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just remember, all scenarios are different, but as a general rule of thumb, the less humidity, the more rainfall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This doesn't mean that places with less humidity &lt;em&gt;must&lt;/em&gt; get rain. No. Rain cloud formation and humidity are completely unrelated. Rain clouds can form in whatever condition and in any place at any time. Humidity on the other hand affects whether or not the raindrops actually touch the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It'll still rain with low humidity, but the raindrops might get absorbed into the air before they hit the ground. In some cases with low humidity, the sun isn't strong enough to evaporate all the water, so there'll only be a light shower. Sorry for the confusion.&lt;/p&gt;&#xA;" OwnerDisplayName="user17688" LastEditorDisplayName="user17688" LastEditDate="2019-10-07T00:43:41.393" LastActivityDate="2019-10-07T00:43:41.393" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18147" PostTypeId="2" ParentId="18141" CreationDate="2019-10-06T17:59:43.557" Score="2" Body="&lt;p&gt;There are things that could do it, but they would be very noticeable. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;A whole string of thousands of the largest volcanic eruptions to ever occur on earth. Volcanoes can briefly match human output, but volcanoes only erupt for a few minutes or hours. you would need the equivalent of mount St Helens erupting continuously for 70 years.  &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The burning if every forest on the planet. I'm sure humans would notice such a firestorm, and I;m not even sure if that would be enough. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The slow extinction of photosynthetic algae. without the bulk of photosynthesis to convert co2 into oxygen it could build up. Of course we monitor this so it would not go unnoticed. More importantly oxygen levels would also drop dramatically which it hasn't. &lt;a href=&quot;https://scied.ucar.edu/imagecontent/carbon-cycle-diagram-ipcc&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://scied.ucar.edu/imagecontent/carbon-cycle-diagram-ipcc&lt;/a&gt; &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The ignition and continuous burning of millions of miles of exposed coal beds. You would need to burn approximately ~3 teratons of coal. coal beds can be ignited by natural causes but we would notice a coal fire larger than a continent. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;A drop in sea level by hundreds of feet would do it. large sea level drop cause outgassing of methane and co2, from wetlands and sea muds. but again New York would notice it if long island stopped being an island. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Some of these have actually happen in earth's geologic history just none recently, and not as consistently as we have managed (at least not since life evolved). Really scientists have spent a lot of time and money looking for other causes, and no one has found any. Scientists concluded it was human activity by eliminating every other conceivable cause. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2019-10-06T21:13:58.110" LastActivityDate="2019-10-06T21:13:58.110" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="18148" PostTypeId="2" ParentId="18086" CreationDate="2019-10-06T18:42:14.233" Score="0" Body="&lt;p&gt;I've found this information in this article &lt;a href=&quot;https://scied.ucar.edu/shortcontent/mount-tambora-and-year-without-summer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mount Tambora and year without summer&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The eruption of Mount Tambora, cited in the first article posted in the question as the worst volcanic eruption of human history (debatable according to other answer in this thread) dropped global temperature 3 degrees celsius. &lt;/p&gt;&#xA;" OwnerUserId="9635" LastActivityDate="2019-10-06T18:42:14.233" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18149" PostTypeId="1" CreationDate="2019-10-06T19:00:37.733" Score="2" ViewCount="272" Body="&lt;p&gt;In many articles on the internet (I'll cite a couple for the sake of the question), smoke from the fires (composed mainly of &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; and CO) following a nuclear war would cool the atmosphere and would cause a &quot;nuclear winter&quot;. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Nuclear winter is a severe and prolonged global climatic cooling&#xA;  effect hypothesized&lt;a href=&quot;https://www.carbonbrief.org/guest-post-did-bombing-during-second-world-war-cool-global-temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt; to occur after widespread firestorms&#xA;  following a nuclear war.[3] The hypothesis is based on the fact that&#xA;  such fires can inject soot into the stratosphere, where it can block&#xA;  some direct sunlight from reaching the surface of the Earth.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.m.wikipedia.org/wiki/Nuclear_winter&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nuclear winter&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In the 1980s, using simple climate models, we discovered that global&#xA;  nuclear arsenals, if used on cities and industrial areas, could&#xA;  produce a nuclear winter and lead to global famine.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Smoke from the fires would last for years in the upper atmosphere,&#xA;  blocking sunlight, and making it cold, dark and dry at the Earth’s&#xA;  surface.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.carbonbrief.org/guest-post-did-bombing-during-second-world-war-cool-global-temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;Did bombing during second world war cool global temperature&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But when we are taking about global warming, oil burning (which releases &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;) contributes towards global warming. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is smoke considered a factor in global cooling when analyzing nuclear winter scenarios, but one of warming when analyzing global warming scenarios?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastEditorUserId="2470" LastEditDate="2020-01-05T19:06:06.370" LastActivityDate="2020-01-05T19:10:05.443" Title="Why is smoke considered a factor of global cooling when analyzing nuclear winter scenarios, but arent when analyzing global warming scenarios?" Tags="|climate-change|temperature|co2|" AnswerCount="5" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18150" PostTypeId="1" CreationDate="2019-10-06T19:01:11.160" Score="1" ViewCount="84" Body="&lt;p&gt;Geothermal cooling has been an attractive option in the U.S. Northeast &#xA;since it emits very little carbon into the atmosphere compared with&#xA;compressed refrigerant systems which use lots of electricity.&#xA;Geothermal cooling is based on the fact that the ground basically&#xA;stays around 50-55 degrees farenheit all year round unless the ground is near&#xA;a hot spring or volcanic fault line.&#xA;I would think that the temperature of the earth will warm&#xA;a little bit which would affect the temperature of the&#xA;cooling fluid.&lt;/p&gt;&#xA;" OwnerUserId="17993" LastEditorUserId="-1" LastEditDate="2019-10-10T07:20:05.460" LastActivityDate="2019-10-10T07:20:05.460" Title="Will geothermal cooling be greatly affected by global warming?" Tags="|geothermal-heat|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18151" PostTypeId="1" CreationDate="2019-10-06T19:15:52.963" Score="1" ViewCount="508" Body="&lt;p&gt;How is that a general rule of thumb that less humidity equals more rain? Deserts don’t get much rain and humidity is also very low. Rainforests get a lot of rain when the humidity is very high so how is that that less humidity equals more rain?&lt;/p&gt;&#xA;" OwnerUserId="17923" LastActivityDate="2019-10-08T07:37:07.773" Title="Deserts and Humidity" Tags="|rainfall|humidity|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18152" PostTypeId="2" ParentId="18140" CreationDate="2019-10-06T19:27:41.100" Score="2" Body="&lt;p&gt;The SMAP includes both an active L-band synthetic aperture radar and a passive microwave radiometer. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any object above a temperature of absolute 0 will emit thermal radiation over a wide range of frequencies.  The spectrum of this radiation can vary from that of a theoretical &quot;black body&quot; depending on its physical properties, especially the dielectric constant.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the bulk dielectric constant of the soil depends on the soil moisture, the spectrum of the thermal radiation from the soil is related to the soil moisture.  The dielectric constant of frozen water is different than for liquid water, so there's a different signal depending on whether the soil moisture is liquid water or ice.  Needless to say, it takes a very sensitive and accurate instrument to measure this thermal radiation in order to estimate the soil moisture.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly, for the active radar, the signal reflected from the soil depends on the dielectric constant of the soil, which is directly related to the soil water content.        &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data from these instruments are combined to produce a surface soil moisture product- this is an estimate of the moisture in the top 5 cm (2 inches) of the soil.  It's important to understand that this is not an estimate of (and is a very poor substitute for) the root zone soil moisture available to crops or other vegetation.  This distinction is important in identifying drought conditions and in predicting transpiration from plants.    &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's a large research literature on using passive radiometers and active radar to estimate surface soil moisture. Is there something more specific about this you'd like to understand? &lt;/p&gt;&#xA;" OwnerUserId="7306" LastActivityDate="2019-10-06T19:27:41.100" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18153" PostTypeId="2" ParentId="18149" CreationDate="2019-10-06T21:21:35.870" Score="2" Body="&lt;p&gt;Your assumption that &quot;smoke&quot; in the sense of your question, i.e. the emissions from a burning event, consists only of &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; is wrong. At least it is not the only factor at play.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During the events you mention, not only &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; is emitted but also loads of other components such as dust, soot, sulphates and many other things. Especially the particulate components are interesting here. Let's call them dust for simplicity (although that use of the word is not entirely accurate).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During emissions at low altitude (such as driving a car) that dust is quickly removed from the atmosphere and has only local impact. But when enough dust gets into higher layers of the atmosphere, it contributes to cloud formation and causes cooling. If there is enough dust it might even have a direct dimming effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; on the other hand only has a warming effect. Also, &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; remains in the atmosphere for very long times (about 1000 years) whereas dust is removed comparatively quickly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is why the scenarios you describe are very different. Also, not all burning has the same ratio of dust to &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that the impact of aerosol on climate is a field of intensive study and is included in current climate modelling.  There are high uncertainties related to this. My answer should only indicate why the things are different. &lt;/p&gt;&#xA;" OwnerUserId="681" LastEditorUserId="2470" LastEditDate="2020-01-05T19:08:34.250" LastActivityDate="2020-01-05T19:08:34.250" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18154" PostTypeId="2" ParentId="18149" CreationDate="2019-10-06T21:25:09.253" Score="-5" Body="&lt;p&gt;The two factions have different points to prove. The nuclear catastrophe faction have to prove that  a nuclear war would be a disaster of the first magnitude, which I don't doubt for a moment, while the global warming faction have to prove that the current warming episode is caused by burning fossil fuels. Forest fires are fairly neutral in that whatever replaces the burned forest, be it more forest, oil palm plantations or conventional farm crops, will extract almost as much CO2 as was released.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;People with points to prove are apt to get carried away, like the Chicxulub enthusiasts who maintain, against the evidence, that a bolide impact on the Yucatan peninsular caused forest fires on the other side of the globe. CO2 emissions from the Deccan Traps super-volcano are usually ignored as a cause of the extinctions. Think of a million Tambora eruptions rolled into one and you have some idea of the Deccan Traps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you may already be aware, you don't need nuclear weopons to set cities on fire. The fire bombing of Tokyo in February 1945 killed 90,000 people, while the nuking of Nagasaki later that year killed 'only' 45,000. There were many such fire bombings during the 2nd World war, yet I have never heard it said that they contributed a  meaningful amount of CO2 to global warming. A lot of war industries were also releasing CO2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One thing I am absolutely certain of is that there has always been climate change and there always will be, and it will not be stopped in its tracks by anything man can do in the 21st century or any other century. Slowed perhaps, but not stopped.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-10-06T21:25:09.253" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18155" PostTypeId="2" ParentId="18150" CreationDate="2019-10-06T21:59:05.607" Score="1" Body="&lt;p&gt;I presume that by geothermal cooling you mean geothermal energy. Yes, it's an attractive option and is used a lot in Iceland, but unfortunately there are not many places that have such easy access to it as Iceland. Geothermal energy will be just one source of non-polluting energy, along with hydro-electricity and many others. Today's global warming is just a passing phase, and will be followed sooner or later by another ice age.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth is gradually cooling as geothermal heat is lost into space and the crust is getting thicker, as has already happened on Mars, but this will have no noticeable effect on Earth for many millions of years, by which time we will have gone to join the dinosaurs.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-10-06T22:04:27.100" LastActivityDate="2019-10-06T22:04:27.100" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="18156" PostTypeId="2" ParentId="18151" CreationDate="2019-10-07T00:39:44.763" Score="2" Body="&lt;p&gt;Humidity doesn't affect whether or not it rains. Rain clouds form on their own. Humidity does control whether or not the rain will touch the ground or not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sorry if I wasn't clear in my other &lt;a href=&quot;https://earthscience.stackexchange.com/questions/18145/humidity-and-rainfall/18146#18146&quot;&gt;answer&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Deserts.&lt;/strong&gt; They don't get a lot of rain because rain clouds never make it to a desert. This can be due to a factor of many reasons. You can read more about it here: &lt;a href=&quot;https://www.quora.com/Why-do-deserts-have-less-rain&quot; rel=&quot;nofollow noreferrer&quot;&gt;Why don't deserts get a lot of rain?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Rain forests&lt;/strong&gt;. Like I said before, humidity doesn't really affect whether or not it will rain. Even though there is high humidity, rain clouds can still form, and it will still rain. Like I said in my other question, the surrounding air can't hold more water, so there will &lt;em&gt;always&lt;/em&gt; be rain in a rain forest if rain clouds are present.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I was trying to say in my other question, is that the surrounding humidity could play a role in whether or not the rain drops actually fall to the ground or not. But rain cloud formation is completely unrelated to humidity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll be sure to edit that question to make it more concise. Sorry for the confusion.&lt;/p&gt;&#xA;" OwnerDisplayName="user17688" LastEditorUserId="595" LastEditDate="2019-10-08T07:37:07.773" LastActivityDate="2019-10-08T07:37:07.773" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18158" PostTypeId="1" CreationDate="2019-10-07T01:30:43.520" Score="1" ViewCount="172" Body="&lt;p&gt;Does precipitation increase or decrease as elevation increases? Because I heard that in the mountains they get more precipitation due to the orographic effect and how the mountains drain the moisture from the clouds but in 8th grade my science teacher told me that precipitation actually decreases as elevation increases so I’m just confused?&lt;/p&gt;&#xA;" OwnerUserId="17923" LastActivityDate="2020-03-05T11:03:15.493" Title="Precipitation and Elevation" Tags="|precipitation|mountains|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18160" PostTypeId="1" CreationDate="2019-10-07T08:55:21.083" Score="1" ViewCount="1099" Body="&lt;p&gt;I think the title says it all...&lt;/p&gt;&#xA;" OwnerUserId="17998" LastActivityDate="2019-10-07T18:01:29.817" Title="Why is CO2 considered a greenhouse gas? Can you explain the principles?" Tags="|atmosphere|atmospheric-radiation|" AnswerCount="1" CommentCount="4" ClosedDate="2019-10-07T19:55:14.353" ContentLicense="CC BY-SA 4.0" />
  <row Id="18161" PostTypeId="2" ParentId="18151" CreationDate="2019-10-07T09:27:46.467" Score="1" Body="&lt;p&gt;I wouldn't say that low humidity equals more rain. The key to the conundrum is the Hadley cell. There are two of them, one on either side of the equator, and they are huge air masses which encircle the globe. What happens is that the equator is heated by the sun, and this huge mass of humid, water laden, tropical air rises to a height of about 7 or 8 miles. As it rises, the pressure falls and the air cools. Cool air at low pressure can hold less water than warm air at high pressure, so the water condenses and falls as rain on the tropical rainforest and tropical seas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus relieved of most of its moisture, the air starts to descend, moving away from the tropics and into the sub-tropics as it does so. Warming and compressing as it passes over the desert areas which lie north and south of the tropics, it becomes much less humid and rainfall is scarce. There are other circulation cells north and south beyond the Hadley cells, but they are much less relevant to your question. Here in Hereford UK I have noticed that rain is more likely when there is high humidity.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-10-07T09:27:46.467" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18162" PostTypeId="2" ParentId="18158" CreationDate="2019-10-07T10:16:56.637" Score="-2" Body="&lt;p&gt;What usually happens is that moisture laden air is blown toward mountains and forced to climb higher. As it rises, it tends to  become colder and less dense, so can hold less moisture. The surplus moisture is often precipitated in the hills or mountains, so when the air passes beyond the mountains there is much less rainfall. This is known as rain shadow. Here in Hereford UK we have plenty of rain, but not nearly as much as some places in the Welsh hills which lie 20 miles to the west of us, so I think we benefit a little from rain shadow. It was my experience in Borneo that there was more rain in the hills than at lower altitudes, but whether this holds true for the summit if Mount Kinabalu, which is over 12,000 feet high, I am not so sure. Probably not. More likely the rain is precipitated on the lower slopes.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-10-07T10:16:56.637" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18163" PostTypeId="2" ParentId="18160" CreationDate="2019-10-07T11:07:07.063" Score="2" Body="&lt;p&gt;Yes, you are right, the title says it all. The presence of greenhouse gases, of which there are several, allows radiant energy from the sun to pass through the atmosphere but hinders the longer wavelength, infra red, thermal radiation from getting back out again, thus acting like the glass in a greenhouse. CO2 is a less effective greenhouse gas than methane, but there is much more of it in the atmosphere and it stays there longer, so this is the one which causes most concern. There are natural processes which reduce the amount of CO2 and methane in the atmosphere as long as the input, mainly from human activity, is not more than they can deal with.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-10-07T18:01:29.817" LastActivityDate="2019-10-07T18:01:29.817" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18164" PostTypeId="1" CreationDate="2019-10-07T18:49:18.057" Score="1" ViewCount="251" Body="&lt;p&gt;I have repeatedly heard from various car enthusiasts that start stop technology has no benefit (or the tiniest smallest negligble benefit) to air quality so they turn it off entirely.  Does it have an effect and how much?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I live in a busy town with many traffic lights in the centre with many traffic lights in the centre, there is a taxi rank where taxis idle for minutes at a time, there are high streets where cars wait outside shops and there are bus stations where buses leave their engines running while loading up passengers.&lt;/p&gt;&#xA;" OwnerUserId="18003" LastActivityDate="2019-10-08T13:16:11.763" Title="Does Start / Stop technology in cars have an impact on air quality?" Tags="|air-pollution|air-quality|air|" AnswerCount="2" CommentCount="6" ClosedDate="2019-10-08T07:50:56.397" ContentLicense="CC BY-SA 4.0" />
  <row Id="18165" PostTypeId="2" ParentId="18164" CreationDate="2019-10-07T18:56:07.957" Score="1" Body="&lt;p&gt;Generally idling will cause pollution in specific isolated areas and start stop technology could irradicate that pollution.  Here I will concentrate not on the global impact of the pollutants but at the location where the pollution is released.  The differing scenarios are important to how much of an effect start-stop / idling will have on air quality.  The location affected by idling will of course determine what air quality affects.  Taxi ranks, junctions, high streets, spaces outside schools, hospitals and other areas where cars often stop for longer than a few seconds.  The longer you idle and the more cars there are, the more pollution you would create in that specific location.  The number and type of person in the location where the idling is taking place would make a difference to how the air quality would affect people.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I present a few scenarios (a link at the bottom for my calculations)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;A long journey with minimal stopping&lt;/strong&gt;&#xA;Here the savings on pollution would be negligible because the car would not be stopped idling for much time at all!  Although of course the locations where the car does stop would be subject to fewer pollutants.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Major junction at 11:30am on a weekday (figures taken from Preston Circus Brighton)&lt;/strong&gt;&#xA;During a full cycle of all traffic lights going from red to green and back for all junctions, 69 cars passed during 112 seconds.  The cars used an estimated 0.451L of petrol.  During this time 32 cars waited for 30 seconds using 0.2L of petrol.  Idling in this scenario is responsible for 44% of the fuel used and therefore I assume idling is responsible for 44% of the pollution.  It is a place where pedestrians will wait at crossings, drivers will sit in their cars, cyclists will stop catching their breath and where pedestrians sometimes have alternative routes.&#xA;44% here is a huge and very significant number.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Single car waiting in a single spot&lt;/strong&gt;&#xA;In a car you would use around 0.75L of petrol per hour idling and you would change that single location from being pollution free to a place equal to a single lane road with regular traffic (1 car every 12 seconds)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;A 1.5km stretch of road with 4 major junctions with traffic lights&lt;/strong&gt;&#xA;A single 1.5km stretch of road could have four major junctions in a busy city.  A car stops twice for a combined total of 2 minutes.  The car will use around 0.025L of petrol idling.  Driving along this stretch of road would use around 0.15L of petrol, assuming the amount of fuel is equal to the pollution then start stop could reduce pollution by 6%.  This is a fairly small amount compared to the total but it is still significant difference in the air quality along a large stretch of road.  Streets like these in city centres will have many more people than in other areas waiting at the lights, walking along pavements, people working in shops, people living in flats above the roads, cyclists and drivers will be in their cars taking in the pollution.  These areas are some of the most dangerous generally for people because of the number of people so 6% could make a significant difference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;A taxi rank&lt;/strong&gt;&#xA;A taxi rank with 10 cars idling in a space of around 35m. That 35m spot could have the air quality equal to a reasonably busy dual carriage way (a car every 1.68 seconds).  Some taxi ranks are covered (such as those near train stations) which could make those spaces much much worse as the pollution would not be dispersed easily. There will be people waiting for taxis next to the taxi rank, people waiting nearby as taxi ranks are usually in busy locations and the taxi drivers themselves will be sitting directly in these toxic fumes so there will be many people exposed to this pollution.  With start-stop, this pollution would be completely eradicated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;A school&lt;/strong&gt;&#xA;The cars could be spread out more so you could say it would be a half of the above, so a busy single lane A road maybe.  The affects of pollution are greater on children because their lungs are smaller, more sensitive and growing.  Children and babies in prams are also more affected because they are shorter and closer to the pollution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://docs.google.com/document/d/1rASB96LRIP1II4vkxGKncshfZpR3iNAy9ONmSHAkTGs/edit?usp=sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://docs.google.com/document/d/1rASB96LRIP1II4vkxGKncshfZpR3iNAy9ONmSHAkTGs/edit?usp=sharing&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18003" LastEditorUserId="18003" LastEditDate="2019-10-08T13:16:11.763" LastActivityDate="2019-10-08T13:16:11.763" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18166" PostTypeId="2" ParentId="18164" CreationDate="2019-10-07T19:24:24.690" Score="1" Body="&lt;p&gt;From &lt;a href=&quot;https://en.wikipedia.org/wiki/Start-stop_system&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In automobiles, a start-stop system or stop-start system automatically shuts down and restarts the internal combustion engine to reduce the amount of time the engine spends idling, thereby reducing fuel consumption and emissions. This is most advantageous for vehicles which spend significant amounts of time waiting at traffic lights or frequently come to a stop in traffic jams. Start-stop technology may become more common with more stringent government fuel economy and emissions regulations. This feature is present in hybrid electric vehicles, but has also appeared in vehicles which lack a hybrid electric powertrain. For non-electric vehicles fuel economy gains from this technology are typically in the range of 3-10 percent, potentially as high as 12 percent.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Many references at the bottom of that page all seem to prove that these systems indeed save fuel, e.g.&lt;br /&gt;&#xA;Ref [2] &lt;a href=&quot;http://www.edmunds.com/car-reviews/features/do-stop-start-systems-really-save-fuel.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Do stop-start systems really save fuel?&lt;/a&gt; describes a hands-on test using three cars, saving 9.5%, 10.9% and 9.5% respectively&lt;/p&gt;&#xA;" OwnerUserId="595" LastActivityDate="2019-10-07T19:24:24.690" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18167" PostTypeId="1" AcceptedAnswerId="18172" CreationDate="2019-10-07T20:14:23.710" Score="5" ViewCount="253" Body="&lt;p&gt;I am writing an app for students that consist in 180 sheets of the most common minerals on Earth's Crust.&lt;/p&gt;&#xA;&lt;p&gt;One of the fields of the sheets is environment of formation.&lt;/p&gt;&#xA;&lt;p&gt;It is important to me to correctly classify environments because I generate with code thousands of questions for a quiz type:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In wich environment would you found calcopyrite?&lt;/p&gt;&#xA;&lt;p&gt;a) Sedimentary&lt;/p&gt;&#xA;&lt;p&gt;b) ....&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;This is my classification of environments of formation of minerals:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Sedimentary&lt;/strong&gt;: diagenesys minerals etc (calcite, halite...).&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Magmatic&lt;/strong&gt;: sensu stricto igneous minerals (quartz, plagioclase...).&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Metamorphic&lt;/strong&gt;: minerals formed on metamorphism (muscovite, clorite...).&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Tardimagmatic&lt;/strong&gt;: stockworcks, IOCG, VMS, etc, derivatived from magma.(copper, pyrite...).&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Hydrothermal&lt;/strong&gt;: basin fluids, veins of hig-medium-low grade (quartz, serpentinite...).&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Exogenous&lt;/strong&gt;: neoformation minerals on surface by (alteration clays...).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;My question is: is this classification correct?&lt;/p&gt;&#xA;&lt;p&gt;I am particullary worried about tardimagmatic environment. I am sure the term is used at Spain, but it migth not be very accurate at anglo saxon Universities, for the english version of my app.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;h2&gt;Update from answers&lt;/h2&gt;&#xA;&lt;p&gt;Thank you very much for answers. Exogenous was totally an inaccurated term and I suspected tardimagmatic was not a very used term, so my clasification will be:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Sedimentary&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Magmatic&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Metamorphic&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Hydrothermal&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Supergenic&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Extraplanetary&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I offer a bounty to see if someobody could sugest another better classifiaction than this one, or just to corroborate this one is correct.&lt;/p&gt;&#xA;" OwnerDisplayName="user12525" LastEditorDisplayName="user20559" LastEditDate="2021-11-04T13:09:53.870" LastActivityDate="2021-11-04T13:09:53.870" Title="Is this classification of mineral formation environments correct?" Tags="|geology|mineralogy|minerals|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18168" PostTypeId="2" ParentId="18136" CreationDate="2019-10-07T23:13:50.923" Score="-2" Body="&lt;p&gt;Apparently, the forcing of the Milankovitch cycli are enough to cross the tipping point for climate change. &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Milankovitch_cycles#/media/File%3AMilankovitchCyclesOrbitandCores.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Measurements of Vostok ice core data and Milankovitch orbital parameters.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17796" LastActivityDate="2019-10-07T23:13:50.923" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18169" PostTypeId="1" CreationDate="2019-10-08T15:53:34.780" Score="2" ViewCount="55" Body="&lt;p&gt;I recently flew into New Jersey over the Delaware river and took this photo of the ridgeline at the Delaware Water Gap.  The trees are mostly green (early October) but on the south-east side of the ridge there is a bright streak of reddish foliage along the entire length of the ridge.  (I noticed this on other hills in the area as well.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What could be causing this color change?  My first guess would be that it is related to sun exposure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/22AJC.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/22AJC.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18007" LastActivityDate="2019-10-08T18:09:35.393" Title="Why does foliage coloration vary on north/south sides of ridge (Northeast USA)?" Tags="|seasons|vegetation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18170" PostTypeId="2" ParentId="18169" CreationDate="2019-10-08T18:09:35.393" Score="3" Body="&lt;p&gt;Your photo doesn't show the strip of autumn-coloured trees very well; without your description I would have taken it for a strip of bare earth. All sorts of things could account for the autumn shades, there are too many unknowns to give a definite answer.       We don't know whether the red-leaved trees are the same species as the others, for example.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I doubt if sun exposure alone could account for it, though it might be a combination of sun exposure and soil conditions, or soil conditions alone. The red trees seem to follow a line where strata different from the rest reach the surface. This would affect the soil conditions, nutrients and perhaps available moisture. Without an investigation on the ground it is impossible to be sure what the cause is, but I think a difference in soil conditions is the most likely explanation.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-10-08T18:09:35.393" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18172" PostTypeId="2" ParentId="18167" CreationDate="2019-10-08T21:31:12.053" Score="3" Body="&lt;p&gt;A genetic classification.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Endogenic: Magmatic, Metamorphic, Hydrothermal&#xA;Exogenic: Supergene, Sedimentary&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For more on this please see Wenk, H. R., &amp;amp; Bulakh, A. (2016). Minerals: their constitution and origin. Cambridge University Press (second edition) &#xA;or the first edition of this book(2004).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FdFN5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FdFN5.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15195" LastActivityDate="2019-10-08T21:31:12.053" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18173" PostTypeId="1" CreationDate="2019-10-09T14:40:14.013" Score="1" ViewCount="67" Body="&lt;p&gt;What causes different locations to get their peak season for thunderstorms at different times of the year like some locations get the most thunderstorms in a July some in June and some in August and some get the most thunderstorms in September. What causes the peak season for thunderstorms to be different in different locations?&lt;/p&gt;&#xA;" OwnerUserId="17923" LastActivityDate="2020-03-07T20:02:20.300" Title="Peak season for Thunderstorms" Tags="|thunderstorm|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18174" PostTypeId="1" CreationDate="2019-10-09T16:24:55.557" Score="10" ViewCount="283" Body="&lt;p&gt;I've been reflecting on climate change and pondering how much of it is truly man-made. Anyone who's shoveled a walkway know that the snow melts faster beside the walkway than it does in the middle of your yard. This is because you've exposed the ground which can absorb the sun's heat. Whereas the snow in the yard reflects it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same is true of glaciers: They melt away from rock faces (ie, terminal morrains, bergschrunds, etc.), and as more of the Earth's surface is exposed, the more heat the surface of the Earth can absorb, and the faster the rest of the Earth's ice can melt. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider the combined surface area of all the roads and parking lots that are cleared of snow each winter (as well as the increased number of roads and parking lots which capture a lot of heat each year). Snow clearing to the scale as is seen in recent decades far exceeds what has been accomplished in the past. Even as recently as the early 20th century people still made their way around on top of the snow in sleighs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How much of a contributor to climate change can be attributed simply to roads and the relatively modern practice of snow removal?  &lt;/p&gt;&#xA;" OwnerUserId="702" LastActivityDate="2020-01-15T00:37:22.907" Title="Does clearing snow contribute to climate change?" Tags="|climate-change|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18175" PostTypeId="2" ParentId="18173" CreationDate="2019-10-09T18:13:18.273" Score="-1" Body="&lt;p&gt;What you are really asking is why the weather varies from place to place, sometimes in places which are only a few miles apart (in the hills of the Dhofar region of S.Oman, you have a transition from monsoon scrub and grassland to arid desert in the space of only 2 or 3 hundred metres!). Weather is such a complex thing it is impossible to enumerate all the factors which cause local variation, except to say that the presence of hills and mountains often has something to do with it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Matter is made up of sub-atomic particles containing positive and negative charges. They are usually evenly distributed, every positively charged particle  being balanced by a negatively charged particle, which means these charges cancel each other out.  Nearly everything we see around us is therefore electrically neutral. This disguises the enormous power of the electromagnetic force, which is trillions of times more powerful than the gravitational force, so even a very slight imbalance between positive and negative charges, such as occurs in thunderstorms, can produce dramatic results. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These electrical imbalances can be produced by air turbulence such as takes place in rising plumes of hot air called thermals, of which the strongest happen in summer. Particles of dust or moisture in the rising air currents rub against each other and cause separation of charge.  The condensing raincloud becomes negatively charged, while the ground below becomes positively charged. Positive and negative charges hate to be separated, as they have a very strong attraction for each other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The positive charges on the ground are pulled along by the negatively charged cloud, and tend to build up on church steeples and similar pointed objects that reach into the sky. When the two masses of separated charge become sufficiently strong, and especially if they pass over a tall, pointed object, they cannot resist the urge to recombine and an electrical discharge takes place. Why one place should have more of these events in August and another in September is a complex question which cannot be answered without knowing all the many variables which influence the weather in both of these places.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-10-09T18:13:18.273" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18176" PostTypeId="2" ParentId="18174" CreationDate="2019-10-09T18:31:46.673" Score="-1" Body="&lt;p&gt;Although snow clearance makes a theoretical difference to climate change by reducing the amount of solar radiation reflected, the difference to average temperatures is negligible, so small as to be unmeasurable. In most cases the snow would melt within a few weeks anyway, so clearance makes no practical difference to global warming.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-10-09T18:31:46.673" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18177" PostTypeId="1" CreationDate="2019-10-09T20:54:00.310" Score="3" ViewCount="106" Body="&lt;p&gt;Surface mining digs up a lot of earth and rock. After the desired ore is separated, where do the earth and rock mined go?&lt;/p&gt;&#xA;" OwnerUserId="7982" LastActivityDate="2019-10-09T21:39:45.933" Title="Where does all the earth from surface mining go?" Tags="|environmental-protection|mining|erosion|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18178" PostTypeId="2" ParentId="18177" CreationDate="2019-10-09T21:39:45.933" Score="1" Body="&lt;p&gt;In opencast mining it is dumped on a huge spoil heap, and if the company is environmentally conscientious or wants to avoid penalties, it is used to fill in the hole left when the mining is finished. With underground mining it is also dumped on spoil heaps, and as it is not practical to infill the mine workings, in best practice the spoil heaps are later landscaped, or at least restored to nature so they are no longer unsightly and could become a nature reserve. Some mining companies are reckless with their waste and dump it into lakes and rivers, potentially causing pollution incidents, though not all mining waste is hazardous.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-10-09T21:39:45.933" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18181" PostTypeId="2" ParentId="18167" CreationDate="2019-10-10T03:59:08.703" Score="4" Body="&lt;p&gt;It is probably not ideal and misleading.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nomenclature first:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have been in several universities, both in the English speaking and non-English speaking world. I also attended multple international conferences. I have never seen the term &quot;Tardimagmatic&quot;. Ever. Also, your &quot;Exogenous&quot; is much more commonly referred to as &quot;supergene&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, most minerals cannot be classified into formation mode. Quartz - can be igneous, metamorphic, hydrothermal, sedimentary, etc. What about garnets? They can be igneous or metamorphic. They can also form by pertitectic partial melting, so they just straddle the igneous-magmatic boundary. Calcite? Another example of a mineral that can be hydrothermal, igneous, metamorphic, or sedimentary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You give the example of chalcopyrite. It can form hydrothermally around igneous intrusions. It can also be sedimentary. Pretty much all minerals can also be metamorphic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I may be blunt here - but this type of learning is old fashioned. Modern learning techniques rarely focus on memorising properties of stuff. This can all be looked up easily online. Teaching now focuses on a systems approach, and understanding of why things happen.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-10-10T03:59:08.703" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18182" PostTypeId="1" AcceptedAnswerId="18189" CreationDate="2019-10-10T09:41:02.960" Score="4" ViewCount="773" Body="&lt;p&gt;Looking at the BBC weather forecasts I've often noticed that strong winds will often be over 40 knots (for the UK at least). Most of the time (nearly always) the wind will jump from 18-22 knots to over 40 from one hour's forecast to the next. I don't often ever see wind speeds in the high 20s or 30s. Why is this the case? I looked at the Weibull distribution but this doesn't seem to apply.&lt;/p&gt;&#xA;" OwnerUserId="18013" LastEditorUserId="2470" LastEditDate="2023-07-15T19:15:28.233" LastActivityDate="2023-07-15T19:15:28.233" Title="Why do wind speeds often jump from 20 knots to 40 knots" Tags="|wind|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18183" PostTypeId="1" CreationDate="2019-10-10T13:03:08.693" Score="3" ViewCount="249" Body="&lt;p&gt;&lt;strong&gt;&lt;em&gt;First of all, the question!&lt;/em&gt;&lt;/strong&gt; :&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Is it possible to predict local weather tendencies for the upcoming hours (let's say 2-3 hours) using only local data?&#xA;If yes, which data is needed to make such predictions and which predictions are possible?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not talking about very precise predictions, just basic stuff like: &quot;The temperature will rise/drop&quot; or &quot;If humidity goes up and air pressure drops, it will probably rain&quot; etc.. you get the idea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was thinking of using data for temperature, air pressure, humidity, time of day and wind speed/direction.. maybe something else?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Some Background&lt;/em&gt;&lt;/strong&gt; :&lt;/p&gt;&#xA;&#xA;&lt;p&gt;for a little DIY Home-Project I decided it would be an interesting idea to set up a little &quot;weather station&quot; in front of my home and collect all sorts of weather related data in short intervalls (e.g. temperature, air pressure, humidity, wind speed/direction, time of day etc.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The idea is to collect data over the period of a few months (or more) and to develop an algorithm that is able to predict the upcoming weather with a certain probability.&#xA;The result should be a little program that was trained on past data and is then able to predict weather tendencies (Temperature, rain, etc..) using the data of the last couple of hours. Let's say the temperature and the air pressure drop and the humidty rises over a certain period of time, then it should tell me that it will likely rain. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will not bother you with the details on how to write such a self-learning algorithm, but since I'm not very well educated regarding meteorology I'm not even sure if such predictions are possible or to what extent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think you've understood the idea. Please give me your Ideas about it. What's possible what's not. Maybe experiences, which data I need, what predictions i could possibly make and which not and so on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for any help!  &lt;/p&gt;&#xA;" OwnerUserId="5274" LastActivityDate="2019-11-11T03:30:53.210" Title="Local Weather Forecast (Self-Learning Algorithm)" Tags="|meteorology|weather-forecasting|data-analysis|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18184" PostTypeId="2" ParentId="18183" CreationDate="2019-10-10T13:17:44.863" Score="3" Body="&lt;p&gt;(not an answer, too long for a comment)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Strictly speaking, the answer is yes, since the temperature generally increases during the day and falls at night (and local time is a local variable), the barometric pressure and humidity can indicate if a storm is coming (there were some really old fashioned weather prediction &quot;clocks&quot; that did this). Realistically, upcoming weather in your local area depends on what's nearby, since that's the weather that moves into your area. Also make sure you don't overfit your model: even a model that perfectly fits your existing data isn't necessarily predictive. Finally, there are lots of weather data available, including local weather data, and you might want to use those data as well.&lt;/p&gt;&#xA;" OwnerDisplayName="user967" LastActivityDate="2019-10-10T13:17:44.863" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18185" PostTypeId="1" AcceptedAnswerId="18188" CreationDate="2019-10-10T13:23:40.763" Score="2" ViewCount="184" Body="&lt;p&gt;In Colombia, many grassy hillsides are terraced, like in the photo below. This terracing also occurs on hillsides that never had these palm trees on them. I assume that it also occurs outside of Colombia. How does this terracing happen?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just from my first-hand observations, I think the answer is: The terracing was formed by grazing livestock. Grazing livestock is common in these areas, and the barbed wire fence hints that it is occurring here. On flat ground, the livestock wander in random directions. On steep ground, the livestock prefer to follow the hill's contour lines, as that is the easiest path to walk, as opposed to more directly uphill or downhill. When a livestock initiates a contour path on a not-yet-terraced hillside, that path is repeatedly trod by subsequent livestock, as it is a little flatter and easier to walk than other contour paths, eventually leading to significant terracing. The terracing is uneven (not level) because the livestock have to go up or down a bit to graze elsewhere on the hill.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anybody confirm my answer, or provide another answer that is objectively correct, preferably with citations? I asked the same question in the form of an &lt;a href=&quot;https://puzzling.stackexchange.com/questions/90003/how-did-these-grassy-hillsides-become-unevenly-terraced&quot;&gt;SE puzzle&lt;/a&gt;, which is currently on hold because &quot;This question may invite speculative answers, as the question is not fully defined. The validity of some answers may be based upon opinion. Good questions for this site [&lt;a href=&quot;https://puzzling.stackexchange.com/&quot;&gt;puzzling.stackexchange.com&lt;/a&gt;] have a limited number of objectively correct answers.&quot; I may be able to save the puzzle with a definitive answer here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hEnmt.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hEnmt.jpg&quot; alt=&quot;Angela Calle and Daniel Di Palma [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Click for &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/e/e4/Valle_del_cocora_-_wax_palm_02.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;high-resolution photo&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Photo credit:&#xA;Angela Calle and Daniel Di Palma [CC BY-SA 4.0 (&lt;a href=&quot;https://creativecommons.org/licenses/by-sa/4.0)]&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://creativecommons.org/licenses/by-sa/4.0)]&lt;/a&gt;&#xA;&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Valle_del_cocora_-_wax_palm_02.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://commons.wikimedia.org/wiki/File:Valle_del_cocora_-_wax_palm_02.jpg&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18014" LastActivityDate="2019-10-13T21:40:35.663" Title="How did these grassy hillsides in Colombia become terraced?" Tags="|vegetation|landscape|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18186" PostTypeId="2" ParentId="18185" CreationDate="2019-10-10T13:58:08.937" Score="0" Body="&lt;p&gt;When I looked at your photograph it immediately occurred to me what the explanation was, but when I read your text I could see you already knew the answer. I can confirm that you are right. These contour lines appear all over the world where grazing animals are kept and there are hills to negotiate, so there is nothing unusual about them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you click 'ancient chalk figures on English hillsides' on Wickipaedia, you will find that almost all the chalk figures have these contour lines around them,and by some amazing coincidence all these hillsides are frequented by grazing animals! One of the best photos showing  what I mean is the Long Man Of Wilmington, which not only shows clear contour lines, but shows the sheep as well.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-10-13T21:40:35.663" LastActivityDate="2019-10-13T21:40:35.663" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18187" PostTypeId="1" CreationDate="2019-10-10T14:26:41.763" Score="3" ViewCount="17" Body="&lt;p&gt;I'm studying a migmatite with two overprinting fold structures. The first (Dn+1) is tight and the second (Dn+2) is gentle. Would it be fair to assume that, since Dn+1's tightness is, well, tighter, then the deviatoric stress applied on it is more intense, or is the correlation tightness-deformation intensity not actually that trustworthy? I'd be grateful if you could link some papers on the subject.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd like to use that as an evidence to the event leading to Dn+1 being closer to the maximum pressure the rock was put under.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks in advance!&lt;/p&gt;&#xA;" OwnerUserId="13211" LastActivityDate="2019-10-10T14:26:41.763" Title="Does fold tightness correlate to deformation intensity?" Tags="|petrology|tectonics|structural-geology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18188" PostTypeId="2" ParentId="18185" CreationDate="2019-10-10T14:47:41.520" Score="3" Body="&lt;p&gt;These are terracettes &lt;br&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Terracette#targetText=In%20geomorphology%2C%20a%20terracette%20is,them%20to%20move%20slowly%20downhill&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Terracette#targetText=In%20geomorphology%2C%20a%20terracette%20is,them%20to%20move%20slowly%20downhill&lt;/a&gt;&#xA; &lt;br&gt; These are caused by natural earth movements as the slope angle is beyond the natural resting angle of the soil. These slopes are a result of rapid erosion e.g. by rivers and glaciers.&#xA;Solifluction &lt;a href=&quot;https://en.wikipedia.org/wiki/Solifluction&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Solifluction&lt;/a&gt; is a similar process.&lt;/p&gt;&#xA;" OwnerUserId="17751" LastEditorUserId="17751" LastEditDate="2019-10-10T14:53:02.713" LastActivityDate="2019-10-10T14:53:02.713" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="18189" PostTypeId="2" ParentId="18182" CreationDate="2019-10-10T17:09:06.430" Score="7" Body="&lt;p&gt;This is an (annoying) artefact of BBC weather forecasts, and not an actual feature of the weather.&lt;/p&gt;&#xA;&lt;p&gt;At low wind speeds, the speed shown is the expected average speed.&lt;/p&gt;&#xA;&lt;p&gt;At higher wind speeds, the speed shown is the maximum expected gust.&lt;/p&gt;&#xA;&lt;p&gt;It changes over when the maximum expected gust is 40 mph (not knots). You can tell the difference because average wind speeds have a white background, and gusts have a black background:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DdBzB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DdBzB.png&quot; alt=&quot;Wind speed transitioning from average to guests on BBC forecast&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;There is a little bit of explanation about half way down this page: &lt;a href=&quot;https://www.bbc.com/weather/about/17185651&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.bbc.com/weather/about/17185651&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="29277" LastEditDate="2023-07-15T11:35:13.363" LastActivityDate="2023-07-15T11:35:13.363" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18193" PostTypeId="1" CreationDate="2019-10-11T09:37:26.797" Score="2" ViewCount="45" Body="&lt;p&gt;Given a location (e.g. Osoyoos, British Columbia) and human eyes only, what's the ranges for the nights of the year most likely to give clear astronomical viewing?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What historical data sources might be mined for a clue? Satellite vs surface? Would the past few years/decades reliably help to predict the future year?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Constrained to the new moon cycle, how might the clearest months be determined?&lt;/p&gt;&#xA;" OwnerUserId="18022" LastActivityDate="2019-10-11T09:37:26.797" Title="Night sky visibility prediction" Tags="|meteorology|weather-forecasting|astronomy|" AnswerCount="0" CommentCount="8" ClosedDate="2019-10-14T06:28:52.923" ContentLicense="CC BY-SA 4.0" />
  <row Id="18194" PostTypeId="2" ParentId="6945" CreationDate="2019-10-11T21:21:01.600" Score="1" Body="&lt;p&gt;If it rains hard enough it will completely strip the atmosphere of CO&lt;sub&gt;2&lt;/sub&gt; in that area.&#xA;A very simple experiment can chart the CO&lt;sub&gt;2&lt;/sub&gt; captured by rain droplets in relation to&#xA;the intensity of the rain over time.  Once it's done raining the replenishment of CO&lt;sub&gt;2&lt;/sub&gt;&#xA;in the depleted area is fairly quick.  It takes about 3 minutes 30 seconds for the CO&lt;sub&gt;2&lt;/sub&gt;&#xA;to evolve. The evolution from start to finish it's a deceleration event.&#xA;Hope this helps everyone out.&lt;/p&gt;&#xA;" OwnerUserId="18024" LastEditorUserId="2470" LastEditDate="2021-02-13T06:26:15.607" LastActivityDate="2021-02-13T06:26:15.607" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18195" PostTypeId="2" ParentId="5001" CreationDate="2019-10-11T23:21:13.680" Score="2" Body="&lt;p&gt;It is not clear that the Obukhov length has an exact physical interpretation. The length L is certainly a length that dimensional argument shows to follow from the set of basis parameters that Monin and Obukhov proposed was sufficient to describe turbulence in the bottom 10% or so of atmospheric boundary layers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We may ask several questions: is the MO basis set complete and unique; is the dimensional argument sound in the face of possible mixed scales (i.e.scales of the form &lt;span class=&quot;math-container&quot;&gt;$\ell_1^{1/2}\ell_2^{1/2}$&lt;/span&gt;), many of which are known in fluid mechanics; is dynamical interpretation possible when the variables in the Reynolds-averaged equations, on which the standard interpretation is based, are defined as ensemble averages (i.e. constructed using flow realizations that have no connection in time)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answers are no, no and no. &lt;/p&gt;&#xA;" OwnerUserId="18025" LastEditorUserId="56" LastEditDate="2019-10-12T04:25:48.953" LastActivityDate="2019-10-12T04:25:48.953" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18196" PostTypeId="1" CreationDate="2019-10-12T03:54:10.830" Score="3" ViewCount="202" Body="&lt;p&gt;Various maps of the Continental Divide (the hydrological  feature, not the trail) contain a loop that looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iV73I.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iV73I.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the hydrologic meaning of the loop in Wyoming? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even if it's a basin, it must have at least a theoretical outlet from which a high enough water level would flow. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or does the definition of the divide treat this as having no outlet, and hence in neither the Atlantic or Pacific watersheds?&lt;/p&gt;&#xA;" OwnerUserId="18032" OwnerDisplayName="Llaves" LastActivityDate="2019-10-13T08:38:41.437" Title="Loop in the continental divide" Tags="|hydrology|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18197" PostTypeId="1" CreationDate="2019-10-12T10:12:29.587" Score="3" ViewCount="177" Body="&lt;p&gt;The CO2 absorption spectrum taken at 200 mmHg partial pressure, beam path length = 10 cm, resolution = 4 cm^-1 shows that light can only travel a couple hundred meters before being completely absorbed by atmospheric CO2 at its absorption peaks. How does extra CO2 increase absorption?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1H3wp.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1H3wp.png&quot; alt=&quot;CO2 infrared absorption&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Answers &lt;a href=&quot;https://physics.stackexchange.com/questions/300046/explain-it-to-me-like-im-a-physics-grad-greenhouse-effect&quot;&gt;here&lt;/a&gt; discussed several mechanisms of spectral broadening and minor absorption bands. But the major absorption bands seem to be wider beyond what a few nanometers of broadening could affect. Would these effects have a non-negligible contribution to carbon dioxide radiative forcing?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As seen in the outgoing spectral radiance taken at the top of the atmosphere, the CO2 absorption peak is only half as high as the blackbody spectrum at the same wavelength. This is contradictory to the argument that the atmosphere is completely opaque in CO2 absorption bands. Does that mean that the thermal emission of CO2 accounts for most of the outgoing radiance at 15 µm? Is there a quick way to see that, and what implications does it have on the radiative forcing of CO2?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mqoNO.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mqoNO.gif&quot; alt=&quot;Upper atmosphere outgoing radiance&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17174" LastActivityDate="2019-10-12T10:12:29.587" Title="How does extra carbon dioxide in the atmosphere contribute to radiative forcing?" Tags="|atmosphere|climate-change|carbon-cycle|atmospheric-radiation|" AnswerCount="0" CommentCount="3" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18198" PostTypeId="2" ParentId="17530" CreationDate="2019-10-12T11:12:00.400" Score="1" Body="&lt;p&gt;Salt does not sink to the bottom in the seas and oceans, because it dissolves in water!&#xA;If you want to get salt from the seas and oceans, try to vaporize them :-)...&lt;/p&gt;&#xA;" OwnerUserId="18028" LastActivityDate="2019-10-12T11:12:00.400" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18199" PostTypeId="1" CreationDate="2019-10-12T12:55:57.207" Score="2" ViewCount="471" Body="&lt;p&gt;Here are two images of English hill figures (The Cerne Abbas giant and the Uffington white horse):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xa9al.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xa9al.png&quot; alt=&quot;cerne abbas giant&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/ofvsv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ofvsv.png&quot; alt=&quot;uffington white horse&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These hillsides, which are obviously grazed by sheep, show tracks that form numerous contour lines around the said hillsides. According to many people, however (e.g., &lt;a href=&quot;https://en.wikipedia.org/wiki/Terracette&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;), these contour lines are not generated by domestic livestock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If that is the case, what causes these lines and why do they only appear on hills that are grazed by livestock? If, on the other hand, no livestock grazes these pastures, what keeps the grass so short and why are English farmers wasting such huge amounts of good grazing land? Are they mad? Some people, such as &lt;a href=&quot;https://earthscience.stackexchange.com/questions/18185/how-did-these-grassy-hillsides-in-colombia-become-terracedP&quot;&gt;this answer&lt;/a&gt;, say the lines are caused by natural earth movements, but won't explain why they only occur on hills that are grazed by livestock. There are many more examples, and better ones, of chalk hill contour lines available on Wikipedia, but my simple explanation of how to find them has been deleted. The Long Man of Wilmington is a much better example than the two photos above, it shows the sheep as well as contour lines and is available on Wikipedia.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-10-14T22:32:17.123" LastActivityDate="2019-10-14T22:32:17.123" Title="How Could Sheep Graze these Steep Hillsides Without Leaving any Marks?" Tags="|geomorphology|" AnswerCount="1" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="18200" PostTypeId="2" ParentId="18196" CreationDate="2019-10-12T13:05:03.797" Score="4" Body="&lt;p&gt;No water flows out of it, apparently...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.onlyinyourstate.com/wyoming/continental-divide-basin-wy/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.onlyinyourstate.com/wyoming/continental-divide-basin-wy/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In summary, there used to be a big lake there, now its a basin with no flows into either ocean. Water there seems to be self contained, accumulating from rainfall and removed by evaporation. &lt;/p&gt;&#xA;" OwnerUserId="18029" LastActivityDate="2019-10-12T13:05:03.797" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18201" PostTypeId="2" ParentId="18196" CreationDate="2019-10-13T08:38:41.437" Score="2" Body="&lt;p&gt;Watershed (catchment) models in GIS, are based on Digital Terrain Model grids of the topography. Errors or uncertainties in the DTM can produce &quot;pools&quot; that will end up being separated from the surrounding catchments. Typically the guidance is to artificially fill these in until they reach the level of the pour point so they will drain to the catchment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, endorheic basins (basins with no stream outflow) of various sizes can be actual hydrologic features with physical meaning. Those should be considered as separate watersheds. The reason this one stands out is that it occurs on the major continental divide, not that it is physically any different in terms of surface water flow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Defining endorheic basins is tricky because some basins can drain in rare wet years. Some may have drained under wetter climatic conditions but now do not. Generally a catchment is considered endorheic if there is no historic record of it draining. &lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2019-10-13T08:38:41.437" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18202" PostTypeId="2" ParentId="18199" CreationDate="2019-10-13T17:24:51.180" Score="6" Body="&lt;p&gt;&lt;strong&gt;Those lines have nothing to do with animals.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Those lines are generated by solifluction and frost heave. It is sometimes referred to as cryoplanation or soil creep. Basically as the thin hillside soil freezes and thaws it expands and contracts and because there is a slop it moves downslope. In addition rain combined with how the surface thaws before the deeped ground causes a plane of weakness and movement. It can form a variety of patterns but on strong slopes it tends to form stripes or ripples. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That area of England is &lt;a href=&quot;http://www.landforms.eu/cairngorms/solifluction.htm&quot; rel=&quot;noreferrer&quot;&gt;well known&lt;/a&gt; for such landform. Below is a picture from Dorset and another from the isle of wight. They don't only occur on grazed ground, but if ground has trees they act as anchors for the soil and you don't get the more noticeable lines and nobody is going to graze animals on ground with nothing but trees or hills with no soil which also will not have them. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/94FVA.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/94FVA.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zGqxE.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zGqxE.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.jstor.org/stable/i303849&quot; rel=&quot;noreferrer&quot;&gt;1. Sugden, David E. (1971). &quot;The significance of periglacial activity on some Scottish mountains&quot;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.cambridge.org/core/journals/quaternary-research/article/frost-creep-and-gelifluction-features-a-review/3C22D3D59491C342383F402B1B372148&quot; rel=&quot;noreferrer&quot;&gt;2. frost creep and gelifluction features a review&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2019-10-13T17:34:11.443" LastActivityDate="2019-10-13T17:34:11.443" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18204" PostTypeId="1" CreationDate="2019-10-14T00:30:02.093" Score="1" ViewCount="27" Body="&lt;p&gt;&lt;strong&gt;Can any natural process explain this rate of CO2 increase?&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;[![1000 years of CO2][1]][1]&#xA;  [1]: &lt;a href=&quot;https://i.stack.imgur.com/MO0mK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://i.stack.imgur.com/MO0mK.png&lt;/a&gt; &lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The prior similar question used different data as its basis.&lt;br&gt;&#xA;This version of the question is much easier to understand. &lt;/p&gt;&#xA;" OwnerUserId="17970" LastEditorUserId="17970" LastEditDate="2019-10-14T14:11:19.833" LastActivityDate="2019-10-14T14:11:19.833" Title="Can any natural process explain this rate of CO2 increase?" Tags="|climate-change|paleoclimatology|" AnswerCount="0" CommentCount="4" ClosedDate="2019-10-14T09:53:36.407" ContentLicense="CC BY-SA 4.0" />
  <row Id="18208" PostTypeId="1" CreationDate="2019-10-14T07:50:33.843" Score="4" ViewCount="75" Body="&lt;p&gt;I'm amateur photographer and professional programmer and I'm trying to create an application to predict exceptionally beautiful sunsets (something like &lt;a href=&quot;https://www.flickr.com/photos/photogtom43/11046818033/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.flickr.com/photos/photogtom43/11046818033/&lt;/a&gt; &lt;a href=&quot;https://www.flickr.com/photos/kemoauc/5369790925/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.flickr.com/photos/kemoauc/5369790925/&lt;/a&gt; )&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of important factors of such sunset is clouds altitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately all open weather APIs do not provide this data. I can compute cloud base from provided temperature and dew point, but it is usually much lower than actual clouds - I got about 700-800m, while clouds were above 6000m (I computed clouds altitude using a time after sunset when clouds were still red)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a way to estimate actual clouds altitude using data I can receive from open APIs or get it in some other way?&lt;/p&gt;&#xA;" OwnerUserId="18042" LastActivityDate="2019-10-14T08:53:25.887" Title="Clouds altitude" Tags="|meteorology|clouds|weather-forecasting|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18209" PostTypeId="2" ParentId="18208" CreationDate="2019-10-14T08:53:25.887" Score="3" Body="&lt;p&gt;Maybe you can use infrared satellite images to get the cloud-top temperatures and estimate the height of them over vertical temperature profiles (e.g. radiosondes). But this ís just workingg for the clouds at the top. You can't see what's beneath them unfortunately.&lt;/p&gt;&#xA;" OwnerUserId="18043" LastActivityDate="2019-10-14T08:53:25.887" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18210" PostTypeId="1" CreationDate="2019-10-14T10:25:18.243" Score="3" ViewCount="158" Body="&lt;p&gt;These photos were taken near Hoganekkal falls in south India. The darker lenses appear to be the same rock type but have varying thickness and do not form a continuous layer. How did this structure form?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/kgHI5.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kgHI5.jpg&quot; alt=&quot;rock features&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18045" LastEditorUserId="6535" LastEditDate="2019-10-16T01:59:06.323" LastActivityDate="2019-12-04T13:01:30.167" Title="How did these dark lenticular features form? (Near Hoganekkal Falls India.)" Tags="|geology|structural-geology|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18211" PostTypeId="1" AcceptedAnswerId="18214" CreationDate="2019-10-14T15:14:56.797" Score="12" ViewCount="8491" Body="&lt;p&gt;I would assume hilly land is more labor-intensive to farm than flat land, and more exhausting to humans and animals if traditional farming techniques are used. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How do farmers plant and plow on uneven terrain? And do the furrows on a hill run uphill-downhill, or “horizontally stacked” up the hill’s incline? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit&lt;/strong&gt;: I see why sloped land is more conducive to other kinds of agriculture. Any idea how steep a grade has to be before farming grain on it is more trouble than it’s worth?&lt;/p&gt;&#xA;" OwnerUserId="18049" LastEditorUserId="18049" LastEditDate="2019-10-16T19:36:41.047" LastActivityDate="2019-10-17T04:04:29.893" Title="How are hillsides farmed?" Tags="|agriculture|" AnswerCount="6" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18212" PostTypeId="2" ParentId="18211" CreationDate="2019-10-14T15:38:45.413" Score="21" Body="&lt;p&gt;The way hillsides are farmed generally depends on the steepness of the hillside. Gentle slopes can be farmed the same way flat land is farmed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Steeper slops require the hillside to be divided into &lt;a href=&quot;https://en.wikipedia.org/wiki/Terrace_%28agriculture%29&quot; rel=&quot;noreferrer&quot;&gt;terraces&lt;/a&gt;. The steeper the slope, the narrower the &lt;a href=&quot;https://www.mnn.com/lifestyle/arts-culture/blogs/9-examples-terrace-farming-around-world&quot; rel=&quot;noreferrer&quot;&gt;terraces&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.worldatlas.com/articles/what-is-terrace-farming.html&quot; rel=&quot;noreferrer&quot;&gt;Terracing of hillsides&lt;/a&gt; in farming reduces erosion because terraces reduce the flow rate of water down the hill. Furrows running down slope can easily transform into &lt;a href=&quot;https://en.wikipedia.org/wiki/Gully&quot; rel=&quot;noreferrer&quot;&gt;erosion gullies&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Terrace farming has been all over the world and for thousands of years. It is speculated that the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hanging_Gardens_of_Babylon&quot; rel=&quot;noreferrer&quot;&gt;Hanging Gardens of Babylon&lt;/a&gt;, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;may have been built on an artificial mountain with stepped terraces, such as those on a &lt;a href=&quot;https://en.wikipedia.org/wiki/Ziggurat&quot; rel=&quot;noreferrer&quot;&gt;ziggurat&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Slopes in the Andes of South America were terrace mining before AD 1000.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-10-14T15:38:45.413" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18213" PostTypeId="1" CreationDate="2019-10-14T18:08:45.147" Score="2" ViewCount="122" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jnUTl.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jnUTl.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This photo was taken at 3000 m above sea level in an open field, during the day.&lt;/p&gt;&#xA;" OwnerUserId="18052" LastEditorUserId="6467" LastEditDate="2019-10-14T18:20:21.220" LastActivityDate="2019-10-15T10:49:13.503" Title="Could this cloud be artificially formed?" Tags="|meteorology|atmosphere|clouds|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18214" PostTypeId="2" ParentId="18211" CreationDate="2019-10-14T18:41:04.023" Score="13" Body="&lt;p&gt;Terrace farming is widespread in the Orient  but it is backbreakingly labour intensive. In UK we don't do it, partly because we don't grow our own rice. Depending on how steep the hill is, we either plough it or use it for grazing. A shallow incline can be ploughed, but you have to be very careful how you do it. Many accidents are caused each year by tractors overturning. This is most likely when you are contouring, i.e sideways to the slope. In a few areas, mainly in Scotland, hills where there is plenty of heather are sometimes used for game preservation and grouse shooting. Another use for hills is forestry, but there is not a lot of forestry in UK.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If there are extensive steep hills on your land, the usual solution is to use them for grazing, which is why there are so many sheep farmers in Wales and other hilly areas. If it's just one steep hill on land which is otherwise fairly level, some farmers leave it to nature rather than risk a nasty accident. So the answer to your question is that hilly land is more labour intensive in the Orient and some similar areas of the world, but not in most of Europe. Furrows generally run up and down hill unless the farmer is confident he can plough transversely without risk of overturning.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-10-14T18:41:04.023" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18215" PostTypeId="2" ParentId="18213" CreationDate="2019-10-14T21:33:15.900" Score="2" Body="&lt;p&gt;I think it could be artificially formed. The parallel background clouds are natural formations; I have seen such formations over Hereford so straight, extensive and parallel that they looked artificial, but weren't. However, the transverse cloud in your photo runs contrary to the natural airflow. One possibility is that an aircraft flew cross grain through or just above the parallel clouds and left a vapour trail behind it. Why isn't the vapour trail longer? Perhaps because only the air near the background clouds is suitable for vapour trails to form. It is not unusual for vapour trails to be discontinuous.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-10-14T21:33:15.900" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18216" PostTypeId="1" CreationDate="2019-10-14T23:03:14.690" Score="2" ViewCount="1267" Body="&lt;p&gt;What is the difference when the weather report says thunderstorms vs when it says thundershowers and the picture is still the same?&lt;/p&gt;&#xA;" OwnerUserId="17923" LastActivityDate="2019-10-15T13:18:09.793" Title="Thunderstorms vs Thundershowers" Tags="|thunderstorm|rain|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18218" PostTypeId="2" ParentId="18216" CreationDate="2019-10-15T06:07:19.150" Score="2" Body="&lt;p&gt;Physically there is no difference. A thunderstorm is defined by occurrence of lightning, no matter how much lightning there is, if it's cloud-to-ground or intercloud. &#xA;Usually if meteorologists talk about thundershowers in weather reports they want to point out that there will be weaker thunderstorms (e.g. without hail, storm, heavy rainfall or the danger of flash floods).&lt;/p&gt;&#xA;" OwnerUserId="18043" LastEditorUserId="18043" LastEditDate="2019-10-15T13:18:09.793" LastActivityDate="2019-10-15T13:18:09.793" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18220" PostTypeId="2" ParentId="18213" CreationDate="2019-10-15T10:49:13.503" Score="8" Body="&lt;p&gt;There's not much context, but my guess is that this was a &lt;a href=&quot;https://en.wikipedia.org/wiki/Fallstreak_hole&quot; rel=&quot;noreferrer&quot;&gt;cavum cloud&lt;/a&gt; (a.k.a. punch hole or fallstreak), that was caused by an aircraft.  The &lt;a href=&quot;https://www.metoffice.gov.uk/weather/learn-about/weather/types-of-weather/clouds/other-clouds/fallstreak-hole&quot; rel=&quot;noreferrer&quot;&gt;UK Met Office describe&lt;/a&gt; how these form:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;They form in clouds of supercooled water droplets, water below 0 °C but not yet frozen. These water droplets need a tiny particle, a nucleus, to freeze or to be cooled below -40 °C.&lt;/p&gt;&#xA;&lt;p&gt;Aircraft punching through this cloud layer can cause air to expand and cool as it passes over the aircraft wings or propeller. This change in temperature can be enough to encourage the supercooled droplets to freeze and fall from the cloud layer in this distinctive pattern.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The Cloud Appreciation Society have a &lt;a href=&quot;https://cloudappreciationsociety.org/gallery/filter/fallstreak-hole-cavum&quot; rel=&quot;noreferrer&quot;&gt;gallery with loads of examples&lt;/a&gt;.  The NASA Earth Observatory blog also has a &lt;a href=&quot;https://earthobservatory.nasa.gov/features/CloudsGallery&quot; rel=&quot;noreferrer&quot;&gt;nice satellite image&lt;/a&gt; from over the Southern US with multiple occurrences at the same time, which also features in Heymsfield et al (2011) &lt;a href=&quot;https://doi.org/10.1126/science.1202851&quot; rel=&quot;noreferrer&quot;&gt;Formation and Spread of Aircraft-Induced Holes in Clouds&lt;/a&gt;, &lt;em&gt;Science&lt;/em&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nWK0I.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nWK0I.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;(NASA image by Jeff Schmaltz, using MODIS data from LANCE/EOSDIS Rapid Response.)&lt;/p&gt;&#xA;" OwnerUserId="106" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-10-15T10:49:13.503" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18221" PostTypeId="2" ParentId="18211" CreationDate="2019-10-15T13:44:40.633" Score="7" Body="&lt;p&gt;Some people use swales on hillsides for farming. Swales are basically a trench that runs along contour lines of a slope and is used to slow water runoff and increase infiltration into the ground. They're good for growing things like fruit trees, berry bushes and grape vines. Once one is created it usually doesn't take a ton of work to maintain.&lt;/p&gt;&#xA;" OwnerUserId="18057" LastActivityDate="2019-10-15T13:44:40.633" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18222" PostTypeId="2" ParentId="17990" CreationDate="2019-10-15T16:26:20.497" Score="5" Body="&lt;p&gt;Timber, shade, nuts, fruits, animal habitat, flowers, landscaping, erosion control, poles for electric power distribution, syrup, spices,coffee, and other things unrelated to global warming. &lt;/p&gt;&#xA;" OwnerUserId="8409" LastEditorUserId="595" LastEditDate="2019-10-29T12:44:10.897" LastActivityDate="2019-10-29T12:44:10.897" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18223" PostTypeId="2" ParentId="18211" CreationDate="2019-10-15T17:36:30.223" Score="7" Body="&lt;p&gt;It entirely depends on what crops you're farming.  Note for example how many vineyards (especially European ones, from my observation) are located on steep hillsides.  In other places, such as the US northeast, you might farm dairy cattle on the hills, or grow maple trees.  IOW, conventional farming of annual crops on hillsides is labor-intensive (and the soil tends to be poorer), so you grow things that don't need annual plowing &amp;amp; planting, like grape vines or fruit trees such as olive: &lt;a href=&quot;http://www.oli-de-mallorca.com/cultivation-olive-grove-majorca.html&quot; rel=&quot;noreferrer&quot;&gt;http://www.oli-de-mallorca.com/cultivation-olive-grove-majorca.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are doing the plow &amp;amp; plant thing on hillsides, you use contour plowing &lt;a href=&quot;https://en.wikipedia.org/wiki/Contour_plowing&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Contour_plowing&lt;/a&gt; or terracing, otherwise heavy rains will soon erode your soil.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2019-10-15T17:36:30.223" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18224" PostTypeId="1" CreationDate="2019-10-15T19:29:19.377" Score="2" ViewCount="130" Body="&lt;p&gt;I know mountains form due to the collision of tectonic plates. But how does such a slow collision have such great impact as to create huge mountains.&#xA;Is there any intuitive explanation for this?&lt;/p&gt;&#xA;" OwnerUserId="18060" LastEditorUserId="39" LastEditDate="2019-10-15T19:59:19.580" LastActivityDate="2019-10-15T21:11:02.000" Title="How do fold mountains form?" Tags="|mountains|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18225" PostTypeId="2" ParentId="18224" CreationDate="2019-10-15T19:58:04.547" Score="2" Body="&lt;p&gt;&lt;em&gt;Some&lt;/em&gt; mountains form from the collision of tectonic plates; volcanoes are different, and there are some other mechanisms too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;IANAgeologist, and perhaps one will be along to give a more technical explanation, but intuitively, it's about viscosity:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you push an object very slowly into a bowl of water, nothing much happens - the water flows around the object.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you push the object equally slowly into a tray of treacle, it's harder work, and you can form a &quot;hill&quot; in front of the object. The treacle flows too slowly to get out of the way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At very high pressures, rock behaves a bit like the treacle[1] - only much more so. It takes a huge force to push one lump of rock into another, but because the rock flows &lt;em&gt;very&lt;/em&gt; slowly, by pushing very slowly you can still create a mountain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1] I realise it's not exactly like treacle. If you're an expert here, feel free to post another answer getting it right :-)&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2019-10-15T21:11:02.000" LastActivityDate="2019-10-15T21:11:02.000" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18226" PostTypeId="2" ParentId="18224" CreationDate="2019-10-15T20:52:24.937" Score="0" Body="&lt;p&gt;The mountains may seem huge, but they are as nothing compared with the multi-trillion-ton mass of a tectonic plate moving at a few centimetres per year. The buckling of an adjacent continental plate is only one way in which mountains are created. Often a moving oceanic plate is deflected downward by the continental plate with which it collides. Driven down into the mantle, the leading edge of the oceanic plate melts, causing plumes of magma to make their way to the surface and form volcanoes along the edge of the continental plate above. The larger mountains of N.Wales and some of Scotland are the remains of ancient volcanoes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not all volcanoes are a result of plate tectonics (though most are), but they can all create mountains. A much rarer cause of mountain building is the impact of a very large meteorite or small asteroid, whichever you care to call it. Fortunately, this only happens every hundred million years or so. Such mountains can be found in Canada, South Africa, and no doubt other parts of the world, usually heavily eroded by the passage of time,&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-10-15T20:52:24.937" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18227" PostTypeId="2" ParentId="18211" CreationDate="2019-10-15T21:32:15.963" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;How do farmers plow on uneven terrain?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Simple answer - they don't.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;if traditional farming techniques are used.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Traditional for who?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In rice farming areas, the tradition is terraces and paddies. No ploughing needed, and planting was entirely human-powered.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Europe, the tradition is animal herding. Areas with upland pastures lend themselves to cattle and transhumance, as practised in much of Europe. Where there is no such pasture, such as in much of the hillier areas of Britain, the tradition is sheep farming. Where the land is more mountainous, the tradition is often goats.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Small quantities of crops will be cultivated in the lowlands, which typically is where families live. But the primary product of the farm will be animal-based, not arable.&lt;/p&gt;&#xA;" OwnerUserId="14995" LastActivityDate="2019-10-15T21:32:15.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18228" PostTypeId="2" ParentId="14915" CreationDate="2019-10-15T21:48:31.520" Score="0" Body="&lt;p&gt;The question is very long as is the answer and I don't have time to review all of it in any detail.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of the atoms in the universe are charged and most of them are moving very fast.   A magnetic field will change the motion of a charged particle - that's basic physics.   Now, magnetism may be hard to visualize, even with the right hand rule, it's not really something the average person is familiar with, but what we can say is that without a magnetic field, fast moving particles can fly directly into a planet's atmosphere and give other molecules a kick leading to their escape.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The in-flying molecules are usually protons or alpha particles, which are low mass and tend to escape the rocky planets anyway, so it's not an even trade.   Any gas molecues that the solar wind knocks out are lost and the solar wind particles, even if temporarily absorbed by the atmosphere, likely escape on their own anyway.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How does the magnetic field protect against that?   It certainly prevents the direct collision from the sun, but some of the captured particles hit the Earth near the magnetic poles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a video, posted on a NASA website with an basic guideline of what happens.  It's pretty clear, at least on this video that many more particles are deflected than hit the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://svs.gsfc.nasa.gov/3902&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://svs.gsfc.nasa.gov/3902&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://svs.gsfc.nasa.gov/vis/a000000/a003900/a003902/CMEstrikesEarth_iPod.m4v&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://svs.gsfc.nasa.gov/vis/a000000/a003900/a003902/CMEstrikesEarth_iPod.m4v&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth, for example didn't have a magnetic field for about a billion years, i&lt;a href=&quot;https://www.wired.com/2010/03/earths-magnetic-field-is-35-billion-years-old/&quot; rel=&quot;nofollow noreferrer&quot;&gt;t first formed about 3.5 billion years ago&lt;/a&gt; and our young sun was probably much more active in terms of coronal mass ejections, so it's likely that Earth, Venus and Mars were all pummeled by the Early magnetic field.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's fairly often said that the magnetic field protects the planet's atmosphere and water-vapor and, as a result, it's necessary for life and I think you're right to question that, because for one, it's good to question things, and for two, there are unanswered questions in this particular field of science.  It's not (to my knowledge) well understood how quickly and under what circumstances a planet can be stripped of it's atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do think a planetary magnetic field does provide some protection and shielding, even if the solar storms may not be entirely to blame for removing water and atmosphere from a planet.   Solar storms are harmful in other ways too, &lt;a href=&quot;https://www.space.com/32942-solar-superflare-risks-for-mars-missions.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;they can be deadly to astronauts&lt;/a&gt;.  Even in the partially protected space station, solar storms are a concern and NASA has long paid attention to the risk of solar storms to astronauts, so creating a magnetic shield around Mars (should we ever send people there) would have other benefits as well beyond whatever protection it provides for the thin Martian atmosphere.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might get some better answers for this on &lt;a href=&quot;https://astronomy.stackexchange.com/&quot;&gt;Astronomy&lt;/a&gt;.  &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2019-10-15T21:48:31.520" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18229" PostTypeId="2" ParentId="18211" CreationDate="2019-10-15T22:28:54.497" Score="2" Body="&lt;p&gt;Contour planting along the slope reduces water runoff and decreases soil erosion so is preferred to planting up and down the slope where possible. Another answer mentioned the danger of equipment rollover when driving along contours. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Combine_harvester&quot; rel=&quot;nofollow noreferrer&quot;&gt;contour combine harvester&lt;/a&gt; was developed in the Palouse region of northwestern USA to reduce the centre of gravity to prevent this and to improve how grain fed through the equipment.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2019-10-15T22:28:54.497" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18230" PostTypeId="2" ParentId="17990" CreationDate="2019-10-15T22:39:34.573" Score="4" Body="&lt;p&gt;Planting trees has a short term benefit in carbon sequestration but will not offset the carbon from fossil fuel burning. However, in some places trees provide a benefit of increasing soil carbon which can have a longer lasting effect. Thus, one benefit is to increase the time needed to implement replacements to fossil fuels. Trees can increase cooling through greater evapotranspiration than grassland, in some climate zones. That, however, may have an impact on water resources. Wood and paper products that are not recycled remove carbon from the natural system, although the effect is small.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Burning wood instead of fossil fuels has a positive impact on the carbon budget where the carbon is recycled back into tree plantations.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2019-10-15T22:39:34.573" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18231" PostTypeId="2" ParentId="18117" CreationDate="2019-10-16T23:19:35.243" Score="1" Body="&lt;p&gt;Several methods are employed to measure ground subsidence: Spirit leveling, &lt;a href=&quot;https://en.wikipedia.org/wiki/Satellite_navigation&quot; rel=&quot;nofollow noreferrer&quot;&gt;GPS (GNSS)&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Remote_sensing&quot; rel=&quot;nofollow noreferrer&quot;&gt;Remote Sensing&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Very-long-baseline_interferometry&quot; rel=&quot;nofollow noreferrer&quot;&gt;Very Long Baseline Interferometry (VLBI)&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Satellite_laser_ranging&quot; rel=&quot;nofollow noreferrer&quot;&gt;Satellite Laser Ranging&lt;/a&gt; to name a few. In the case of modeling subsidence caused by water and oil extraction, the most common measuring methods seem to be Spirit leveling, GPS and Remote Sensing (Interferometric synthetic aperture radar and radar altimetry), with varying degrees of accuracy. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Spirit leveling is an efficient and cheap method to determine point elevations. It works well for relatively small areas up to several kilometers, and the surveys can be achieved at less cost. However, when the study area is very large (country or continent-wide), the overall accuracy and consistency of this classical method falls short of space-based techniques: continent-wide classical surveys can have distortions up to a meter or more. Also, it needs good benchmarks, ideally located on a more stable portion of ground around the study area. &lt;/li&gt;&#xA;&lt;li&gt;Continuously operating GNSS stations are another way to measure&#xA;subsidence by plotting positions regularly and creating time series&#xA;to detect movement with an accuracy of about a centimeter. This&#xA;method has the advantage that it is accurate over large areas,&#xA;however, it is much more expensive, so fewer points can be measured,&#xA;resulting in a sparser spatial coverage of the study area.&lt;/li&gt;&#xA;&lt;li&gt;Remote sensing with &lt;a href=&quot;https://en.wikipedia.org/wiki/Interferometric_synthetic-aperture_radar&quot; rel=&quot;nofollow noreferrer&quot;&gt;InSAR&lt;/a&gt; and satellite altimetry can also provide&#xA;very dense Digital Elevation Models for little cost, and works well&#xA;for small to medium sized areas, and usually has a decent accuracy of&#xA;a few centimeters. They can provide interesting input maps for the&#xA;study of land subsidence.&lt;/li&gt;&#xA;&lt;li&gt;Other tools such as piezometers, extensometers, can measure&#xA;compaction and water elevation in aquifers to provide other useful&#xA;data to better understand subsidence.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Other forms of subsidence/uplift studies that may require an even higher degree of accuracy, for example, isostatic rebound/subsidence, plate tectonics, etc. are better monitored using a wider mix of other space geodetic techniques, including Very Long Baseline Interferometry, Satellite Laser Ranging, etc. to get down to the millimeter-level. Such techniques use high-end equipment, radio-telescopes, lasers, etc. to help maintain reference frames and model crustal displacements on a global scale. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a side note, the center of mass can be deduced by observing satellite motions. Satellite laser ranging provides key input as it can measure accurate distances between ground stations and satellites, and VLBI provides Earth orientation and distances between stations. With all those inputs, the origin of the world reference frame (the most recent realization as of 2019 being ITRF2014) is consistent with the center of mass at the centimeter level, and satellite orbits are tracked and corrected to account for Earth dynamics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following web page on USGS has interesting information for further reading on this topic:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.usgs.gov/centers/ca-water-ls/science/measuring-and-monitoring&quot; rel=&quot;nofollow noreferrer&quot;&gt;Measuring and Monitoring Land Subsidence in California&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17236" LastActivityDate="2019-10-16T23:19:35.243" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18233" PostTypeId="1" AcceptedAnswerId="18234" CreationDate="2019-10-17T05:11:53.947" Score="2" ViewCount="79" Body="&lt;p&gt;The PBS Newshour article &lt;a href=&quot;https://www.pbs.org/newshour/science/scientists-discover-big-storms-can-create-stormquakes&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scientists discover big storms can create ‘stormquakes’&lt;/a&gt; says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A stormquake is more an oddity than something that can hurt you, because no one is standing on the sea floor during a hurricane, &lt;strong&gt;said Wenyuan Fan, a Florida State University seismologist who was the study’s lead author.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;The combination of two frightening natural phenomena might bring to mind “Sharknado ,” but stormquakes are real and not dangerous.&lt;/p&gt;&#xA;&lt;p&gt;“This is the last thing you need to worry about,” Fan told The Associated Press.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Storms trigger giant waves in the sea, which cause another type of wave. These secondary waves then interact with the seafloor — but only in certain places — and that causes the shaking, Fan said.&lt;/strong&gt; It only happens in places where there’s a large continental shelf and shallow flat land.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Unfortunately the article does not link to or identify the published study.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Are there more technical terms or clarifications for the following items?&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;stormquake&lt;/li&gt;&#xA;&lt;li&gt;storm-triggered giant waves&lt;/li&gt;&#xA;&lt;li&gt;another type of wave (secondary waves)&lt;/li&gt;&#xA;&lt;li&gt;&amp;quot;certain places&amp;quot;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-10-17T07:11:01.393" Title="What's really happening with &quot;stormquakes&quot;?" Tags="|meteorology|oceanography|waves|storms|sea-floor|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18234" PostTypeId="2" ParentId="18233" CreationDate="2019-10-17T07:07:46.710" Score="5" Body="&lt;p&gt;The article can be found here in Geophysical Research Letters:&lt;/p&gt;&#xA;&lt;p&gt;Fan, W., McGuire, J. J., Groot‐Hedlin, C. D., Hedlin, M. A. H., Coats, S., &amp;amp; Fiedler, J. W. ( 2019). &lt;em&gt;Stormquakes&lt;/em&gt; Geophysical Research Letters, 46. &lt;a href=&quot;https://doi.org/10.1029/2019GL084217&quot; rel=&quot;noreferrer&quot;&gt;https://doi.org/10.1029/2019GL084217&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Abstract&lt;/p&gt;&#xA;&lt;p&gt;Seismic signals from ocean‐solid Earth interactions are ubiquitously recorded on our planet. However, these wavefields are typically incoherent in the time domain limiting their utilization for understanding ocean dynamics or solid Earth properties. In contrast, we find that during large storms such as hurricanes and Nor'easters the interaction of long‐period ocean waves with shallow seafloor features located near the edge of continental shelves, known as ocean banks, excites coherent transcontinental Rayleigh wave packets in the 20 to 50 s period band. These “stormquakes” migrate coincident with the storms, but are effectively spatiotemporally focused seismic point sources with equivalent earthquake magnitudes that can be greater than 3.5. Stormquakes thus provide new coherent sources to investigate Earth structure in locations that typically lack both seismic instrumentation and earthquakes. Moreover, they provide a new geophysical observable with high spatial and temporal resolution with which to investigate ocean wave dynamics during large storms.&lt;/p&gt;&#xA;&lt;p&gt;Plain Language Summary&lt;/p&gt;&#xA;&lt;p&gt;Large storms such as hurricanes and Nor’easters generate strong long‐period ocean waves, which can interact with shallow seafloor features located near the edge of continental shelves known as ocean banks. Such interactions produce seismic sources with equivalent earthquake magnitudes that can be greater than 3.5. These seismic sources are termed “stormquakes”, and they can excite coherent seismic wave fields that are well recorded across the North American continent. Stormquake is a newly identified geophysical phenomenon, which involves interactions of atmosphere, ocean, and the solid Earth. Therefore, stormquakes can provide useful information to investigate the Earth structure and ocean wave dynamics.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;At the moment the link there to the PDF works and is not paywalled.&lt;/p&gt;&#xA;" OwnerUserId="18043" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-10-17T07:11:01.393" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18235" PostTypeId="1" CreationDate="2019-10-17T09:24:28.553" Score="3" ViewCount="78" Body="&lt;p&gt;I have studied about tephigrams. In all the books, it has written that isotherms and dry adiabats are skewed to certain degrees. But practically I could not connect it. How is it possible that constant temperatures and dry adiabats as well as dew points are skewed? Please explain it.&lt;/p&gt;&#xA;" OwnerUserId="18071" LastEditorUserId="2470" LastEditDate="2020-01-05T19:35:22.020" LastActivityDate="2020-01-05T19:35:22.020" Title="Why are isotherms skewed to 45 degrees in the tephigram?" Tags="|atmosphere|climate|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18236" PostTypeId="1" CreationDate="2019-10-17T10:10:09.810" Score="3" ViewCount="92" Body="&lt;p&gt;I'm trying to figure out how to read and extract Topex/Poseidon satelite altimeter data from the Physical Oceanography Distributed Active Archive Center (PO.DAAC). Link to product: &lt;a href=&quot;https://podaac.jpl.nasa.gov/dataset/PODAAC_MGDR&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://podaac.jpl.nasa.gov/dataset/PODAAC_MGDR&lt;/a&gt;.&lt;br&gt;&#xA;The products are L2 MGDRB. They provided a software written in ANSI C language which according to their README file is an interactive dump program and asks for a starting and ending record of the pass file. It lists the header records followed by one or more data records.&lt;br&gt;&#xA;The question is: Are there any other simpler tools to read and extract data from these files or do I need to learn C programming?&#xA;I've already tried using GIS and SNAP but with no results.&lt;/p&gt;&#xA;" OwnerUserId="11987" LastActivityDate="2019-10-17T10:10:09.810" Title="Topex/Poseidon satellite data reading and extracting" Tags="|satellites|nasa|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18238" PostTypeId="1" AcceptedAnswerId="18242" CreationDate="2019-10-17T20:00:57.790" Score="2" ViewCount="82" Body="&lt;p&gt;So I was recently watching &lt;a href=&quot;https://www.youtube.com/watch?v=bfr82RB72U8&quot; rel=&quot;nofollow noreferrer&quot;&gt;this video&lt;/a&gt; regarding desalination efforts around the world and the viability of desalination as a means to provide humans with freshwater. I had a few questions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1 - They mention that the brine that is released as a byproduct of the process is potentially harmful to marine life, so why not just dump it in the desert? Why do we need to release back in the ocean? I'm sure the effects of this won't be that big given that desalination is a tiny percentage of the world's water production. And if anything, given that global sea levels are rising, this might help things, right?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2 - The video states that the vast majority of desalination plants these days use reverse osmosis desalination and not heat-based methods. Why is that so? How is a process that requires energy better than using solar energy to evaporate the water? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Heat-based methods require energy from the sun, yes. But the way I imagine things, we can passively let in water from the ocean, put it under some glass panel that magnifies sun energy, and then let the water evaporate out through some piping to condense somewhere else. How is powering a pump through a membrane (that requires cleaning after) better?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;A lot of these thoughts are just me thinking out loud with no data to back me up because honestly, I wouldn't know what to look up regarding things like this. I'd love some science-based replies to this! I'm definitely missing something big.&lt;/p&gt;&#xA;" OwnerUserId="18077" LastActivityDate="2019-10-18T06:32:29.940" Title="Why is reverse osmosis desalination the dominant method used and not heat-based methods? Also why is brine being dumped back into the ocean?" Tags="|oceanography|water|environmental-protection|desert|" AnswerCount="3" CommentCount="1" ClosedDate="2019-10-18T08:01:20.490" ContentLicense="CC BY-SA 4.0" />
  <row Id="18239" PostTypeId="1" CreationDate="2019-10-17T20:47:51.523" Score="1" ViewCount="30" Body="&lt;p&gt;Let's say I'm extracting precipitation from a single pixel or region from a reanalysis (MERRA-2, ERA-5, Interim) dataset.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can infer a distribution for the daily data (Gamma, Pearson-III, e.g. &lt;a href=&quot;https://pdfs.semanticscholar.org/2118/8e1e04ab60c68dabc6c20e254953c4501c98.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt;), but I know that it will be &lt;strong&gt;conservative&lt;/strong&gt; since I'm basing the distribution on a reanalysis product (smoothed, spatially averaged out).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there an &lt;strong&gt;appropriate method to approximate the &quot;real/actual&quot; local precipitation distribution&lt;/strong&gt; from a reanalysis dataset?&lt;/p&gt;&#xA;" OwnerUserId="7689" LastActivityDate="2019-10-17T20:47:51.523" Title="How to infer local precipitation from reanalysis data?" Tags="|precipitation|reanalysis|weatherdata|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18240" PostTypeId="2" ParentId="18238" CreationDate="2019-10-17T21:22:51.473" Score="2" Body="&lt;p&gt;One factor that makes distillation expensive is the alloys necessary for equipment to handle hot brine are very expensive. For ambient temperature osmosis fairly common stainless like 316 is satisfactory although care must be taken in design to avoid crevices and other considerations.  &lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2019-10-17T21:22:51.473" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18241" PostTypeId="2" ParentId="18238" CreationDate="2019-10-17T22:43:56.757" Score="1" Body="&lt;p&gt;Dumping the brine in a desert would probably be a viable solution in a few places, but many towns don't have a handy desert nearby. It would need to be a really barren desert,almost devoid of life, which few deserts are. Environmentalists would be aghast if you flooded the Sonoran Desert with brine. Bonneville Salt Flats might be better, but they are used for motor sports and are a prime location for breaking land speed records. Great care would have to be taken not to contaminate the water table which underlies most deserts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think the ocean will have to remain the main means of disposing of brine. You would need to be careful where you pumped it as some marine ecosystems are much more sensitive to increased salinity than others, but I have not yet heard of any serious harm done by brine disposal at sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you suggest, solar energy would in theory be a good way to purify water. There are some very small scale solar stills which do just that, but they are only practical in countries where there is hot sunshine almost every day. The difficulty comes when you try to scale it up so that it could supply a city. This has never been done successfully, partly because it would have to compete with established methods like reverse osmosis.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-10-18T06:32:29.940" LastActivityDate="2019-10-18T06:32:29.940" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18242" PostTypeId="2" ParentId="18238" CreationDate="2019-10-18T02:38:18.617" Score="4" Body="&lt;p&gt;Starting with question 2): you can use heat to evaporate the water but you need some sort of energy or thermal exchange to cool and condense it back to liquid. My understanding is that reverse osmosis (RO) is more energy efficient overall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Question 1) Brine is only put into the oceans from system that are near the sea, which usually use seawater as a water source. The brine has an insignificant effect on the ocean salinity once it is mixed in but can have a local effect because of poor mixing and because differences in density between the brine and seawater cause it to sink to the bottom. Systems can be engineered to minimise the impact.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Inland, the brine can degrade groundwater resources if it is disposed to seep into the ground. Even in hot, dry climates, it may be difficult to completely evaporate it to dryness in lined basins so it doesn't seep in. Seepage basins are a viable option in some places where the groundwater is already to salty to use as a resource (for example where the salty water is extracted, put through an RO system and then reinjected to the same aquifer).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;RO systems are designed so that the salty concentrate is removed during operation so the system doesn't need to be cleaned to remove the salt. However, impurities may still require cleaning of the membranes. There are ways to minimize the amount of cleaning needed.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2019-10-18T02:38:18.617" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18243" PostTypeId="1" CreationDate="2019-10-18T09:16:08.410" Score="1" ViewCount="66" Body="&lt;p&gt;I am trying to understand the role of various meteorological factors on agricultural yield over India. Is there a dataset available directly or an indirect proxy of agricultural data, maybe satellite, if any product is there&lt;/p&gt;&#xA;" OwnerUserId="18076" LastActivityDate="2020-03-16T13:50:26.753" Title="What data of agricultural yield to use for India?" Tags="|meteorology|agriculture|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18244" PostTypeId="2" ParentId="16907" CreationDate="2019-10-18T13:28:45.290" Score="4" Body="&lt;p&gt;There is &lt;a href=&quot;https://link.springer.com/article/10.1007/s00445-011-0534-4&quot; rel=&quot;nofollow noreferrer&quot;&gt;a paper about this in the Bulletin of Volcanology&lt;/a&gt; (Hetényi et al. 2012).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cooling rate seems to be the main parameter controlling column size (faster cooling yielding to thinner columns). According to the authors, cooling rate is itself controlled by two non-independent factors: (1) the geometry of the lava body, and (2) the chemical composition of the lava.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;(1) Geometry&lt;/strong&gt; of the lava body influences the boundary conditions for cooling, depending on the emplacement setting (air, host rock, ice...). In the case of a lava lake (figure 2b), lava close to the lake walls will cool faster than lava at the centre of the lake, resulting in thinner columns. Thickness also plays a major role, as shown by figure 10: thicker lava bodies cool slowly, generating thicker columns.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;(2) Chemistry&lt;/strong&gt; plays a role (figure 11): felsic (SiO&lt;sub&gt;2&lt;/sub&gt;-rich) lavas tend to have thicker columns than mafic lavas. It seems a bit counter-intuitive, as felsic lavas are usually emplaced at a &quot;low&quot; temperature and should thus cool faster than a basalt emplaced at 1200 °C... But felsic lavas are more viscous and tend to form thicker flows -&gt; back to (1).&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2019-12-16T09:44:56.613" LastActivityDate="2019-12-16T09:44:56.613" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18245" PostTypeId="2" ParentId="9989" CreationDate="2019-10-18T15:43:42.553" Score="2" Body="&lt;p&gt;Dr. Fujita constructed a scale connecting Beaufort Force, Fujita Scale, and Mach number which shows that the Fujita Scale theoretically goes to 12 (F12). As fortunate (and as horrible) as it would be to successfully ride out an EF5, imagine if you will surviving a tornado packing Mach 1 winds! !?! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dAGX2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dAGX2.jpg&quot; alt=&quot;Dr. Fujita&amp;#39;s&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18083" LastActivityDate="2019-10-18T15:43:42.553" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18247" PostTypeId="1" AcceptedAnswerId="18250" CreationDate="2019-10-18T18:43:22.497" Score="5" ViewCount="2485" Body="&lt;p&gt;Suppose you were sitting near the epicenter of an earthquake, sitting down on flat land without much else near by, maybe some grass. Is it still possible that say, a magnitude 8 or 9 earthquake would be lethal, assuming you can spread out enough to avoid tipping over and hitting your head?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems like the biggest damage in earthquakes comes from buildings, not the ground splitting apart, but it is also possible the terrain itself could warp like an ocean wave several meters I guess. And if a fissure was opening up near someone from the quake's epicenter, would they have time to react and avoid being dropped into it? &lt;/p&gt;&#xA;" OwnerUserId="18085" LastEditorUserId="18085" LastEditDate="2019-10-19T11:42:58.147" LastActivityDate="2023-09-17T06:03:00.870" Title="Could an earthquake on flat land still kill someone without any buildings/boulders or such near by?" Tags="|earthquakes|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18248" PostTypeId="1" CreationDate="2019-10-18T19:55:51.707" Score="3" ViewCount="636" Body="&lt;p&gt;What if humanity burns all fossil fuels it can find? Putting the negative effects of climate change aside, would the enormous amount of &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; in the atmosphere eventually make it unbreathable?  &lt;/p&gt;&#xA;" OwnerUserId="18086" LastEditorUserId="7314" LastEditDate="2020-01-09T17:43:58.537" LastActivityDate="2020-01-09T23:51:07.957" Title="Could burning all fossil fuels (available on earth) render the atmosphere unbreathable?" Tags="|atmosphere|climate-change|fossil-fuel|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18249" PostTypeId="2" ParentId="18248" CreationDate="2019-10-18T21:01:30.720" Score="-2" Body="&lt;p&gt;No. For a start, humanity will not burn all the fossil fuels it can find. But let's suppose for the sake of argument that humanity recognises no restrictions and fulfils all its energy needs by burning fossil fuels. Only a limited amount of fossil fuels are recoverable; the vast majority will have to stay in the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oil, for example, won't suddenly run out. What would happen is that it would gradually become scarcer, and increasingly expensive to recover. Eventually it would become too expensive to burn, so humans would have to turn to other fossil fuels, coal being the obvious one. Some would be used to make synthetic oil, and some burned in its natural state. The world has very large recoverable reserves of coal There could be enough to last humanity for a thousand years, but eventually recoverable reserves would become so scarce that it too would become too expensive to burn and, like oil, would be used as a source of chemicals and plastics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All these fuels together, oil, gas and coal, might conceivably be burned for 2,000 years before becoming too scarce and expensive to be used as fuels. During that time,plants,especially in the oceans, would not be idle. Much of the CO2 generated would be sequestered by natural means, and although there would be a big rise in atmospheric CO2 with consequent climate warming, it wouldn't be nearly enough to make the atmosphere unbreathable.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-10-18T21:01:30.720" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18250" PostTypeId="2" ParentId="18247" CreationDate="2019-10-18T21:34:07.230" Score="4" Body="&lt;p&gt;Yes, a person in the open sitting on grass could be killed by a magnitude 8 or 9 earthquake, but in the circumstances you describe it would be very unlikely. Not all large earthquakes produce huge rifts on land, but if you were unlucky enough to have one open up beneath you then the chances are you would fall into it. Another danger would be liquefaction. In some places the moisture content of the land is such that although in normal circumstances it is perfectly solid and stable, when subjected to the violent shaking of an earthquake a phenomenon called liquefaction occurs. The ground becomes a sort of quicksand into which buildings can collapse and humans disappear. It is quite rare, however, and fatalities among people are unlikely if they are out in the open where nothing can fall on them, though I dare say a few unlucky ones might have a heart attack. On hard ground,though, even a fit and healthy young person might be severely bruised and shaken in a magnitude 9 quake.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="-1" LastEditDate="2023-09-17T06:03:00.870" LastActivityDate="2023-09-17T06:03:00.870" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18252" PostTypeId="2" ParentId="18248" CreationDate="2019-10-19T02:38:05.297" Score="1" Body="&lt;p&gt;Not directly.  What possibly could happen is that rising temperatures turn the parts of the ocean anoxic, which leads to large releases of hydrogen sulfide, which is toxic: &lt;a href=&quot;https://www.chemistryworld.com/news/ocean-chemistry-changes-triggered-earths-greatest-extinction-event/2500368.article&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.chemistryworld.com/news/ocean-chemistry-changes-triggered-earths-greatest-extinction-event/2500368.article&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2019-10-19T02:38:05.297" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18253" PostTypeId="1" AcceptedAnswerId="18257" CreationDate="2019-10-19T09:05:24.097" Score="1" ViewCount="70" Body="&lt;p&gt;In 1960, NASA launched the &quot;Echo 1A&quot; balloon which had amongst its objectives to test the triangulation principle with satellites.&#xA;I wonder why we don't have more &quot;ballon&quot; satellites for our GPS system : they are really less expensive to operate. The only problem I see is the wind, which makes their localisation quite unpredictable. At which altitude a balloon would not be affected by the wind?&lt;/p&gt;&#xA;" OwnerDisplayName="user18090" LastActivityDate="2019-10-19T11:39:29.443" Title="At what altitude a ballon is no longer pushed by the wind?" Tags="|atmosphere|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18256" PostTypeId="2" ParentId="18253" CreationDate="2019-10-19T10:25:45.927" Score="0" Body="&lt;p&gt;A balloon satellite like Echo is obviously more affected by the 'wind' (aerodynamic drag) than a normal satellite in low earth orbit would be, but the GPS satellites are so far out that they are unaffected by Earth's atmosphere. Whether this would be true for balloons, with their much greater drag,I am not sure, but in any case they would still have the solar wind to contend with. In the course of time this would be enough to move them out of position.There is no altitude between Earth and the GPS system where Echo-type balloons would not be affected by a wind of some kind.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-10-19T10:25:45.927" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18257" PostTypeId="2" ParentId="18253" CreationDate="2019-10-19T11:39:29.443" Score="2" Body="&lt;p&gt;In the range where a balloon can fly, there is always wind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The NASA Echo 1A satellite was used to test the satellite triangulation. GPS works in some other way...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The GPS system used active satellites (non-pasive as Echo 1A) that constantly supplies their position, their time and additional coding information. So the satellite position should be known and corrected constantly. With a balloon constellation it will be very difficult.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Supposing that we can install all the equipment in a balloon, the top we could reach will be &lt;a href=&quot;https://en.wikipedia.org/wiki/High-altitude_balloon&quot; rel=&quot;nofollow noreferrer&quot;&gt;53 km&lt;/a&gt;. The actual Navstar GPS constellation it is working at 20.200 km from our surface. So it means that we will need a lot of balloons in order to create a similar network, with a lot of ground stations to manage it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even if that point could be possible, there will be additional problems, as the areas with no islands or no continents when additional ground stations should be required to correct the signal and position.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The actual &lt;a href=&quot;https://en.wikipedia.org/wiki/Global_Positioning_System&quot; rel=&quot;nofollow noreferrer&quot;&gt;GPS satellite geometry&lt;/a&gt; was decided in order to reduce the number of satellites with the maximum cover.&lt;/p&gt;&#xA;" OwnerUserId="18035" LastActivityDate="2019-10-19T11:39:29.443" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18258" PostTypeId="2" ParentId="17990" CreationDate="2019-10-19T12:19:58.953" Score="1" Body="&lt;p&gt;Take a look to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;Carbon Cycle&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the atmosphere there is around 700 Gt of carbon, most of it CO&lt;sub&gt;2&lt;/sub&gt;. The living biomass (plants + animals) keep 600 Gt and the dead biomass is 1000 Gt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So biomass it is very effective in order to fix CO&lt;sub&gt;2&lt;/sub&gt; as it is fixing in 2 ways: photosynthesis (absorbing CO&lt;sub&gt;2&lt;/sub&gt; and emitting O&lt;sub&gt;2&lt;/sub&gt;) and, when biomass dies, then it is fixed on the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you deforest, you are removing the biomass that takes some direct CO&lt;sub&gt;2&lt;/sub&gt; and you are exposing or removing the carbon fix on the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Really, they are not the main actors on the picture: Oceans (38,400 Gt, &#xA;lithosphere carbonates 60,000,000 Gt, lithosphere kerogen 15,000,000 Gt) but their cycles takes 100 years on the fastest one and hundreds of million years on the slower. But the fastest one is the biomass, and the most effective one is the tree. (Check Kiri tree)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://science.sciencemag.org/content/365/6448/76&quot; rel=&quot;nofollow noreferrer&quot;&gt;Take a look&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18035" LastEditorUserId="2470" LastEditDate="2020-01-14T03:40:19.903" LastActivityDate="2020-01-14T03:40:19.903" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18259" PostTypeId="1" CreationDate="2019-10-20T10:30:25.207" Score="3" ViewCount="83" Body="&lt;p&gt;Are total volcanic emissions worldwide constant, or do they rise and fall? We know there are large fluctuations on a scale of tens of millions of years, but is the total volume of emissions stable on a scale of tens of thousands, the last ten thousand in particular? The last major increase that I know of was shortly before the extinction of the dinosaurs and according to some geologists was the cause of the extinctions at the end of the Cretaceous, but I suspect there have been further significant episodes of volcanism since then.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-10-20T13:27:26.950" LastActivityDate="2020-01-06T13:35:14.047" Title="Has the Average Volume of Volcanic Emissions Been Constant Since the Last Major Fluctuation?" Tags="|emissions|paleoclimate|" AnswerCount="2" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18260" PostTypeId="1" AcceptedAnswerId="18267" CreationDate="2019-10-20T10:35:49.370" Score="8" ViewCount="6729" Body="&lt;p&gt;I've been piloting a drone yesterday and made a video hovering at around 100m, the visibility was very good. I've shown the video to a friend of mine and we were arguing whether it's the curvature of the Earth visible at horizon, or is it just camera lens disturbing the image.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm rather sure it's curvature of the Earth, but still don't know how to prove it. I already checked that on the lower part of the picture the buildings-roofs are lined up straight, no disturbance. Yet the horizon is slightly bent (checked by putting a piece of paper on the screen). Which I think already proves the point: should lens disturb the picture, the disturbance would be visible both on the upper and lower part of the picture symmetricly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've read &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7283/how-high-must-one-be-for-the-curvature-of-the-earth-to-be-visible-to-the-eye?newreg=6db86abf42cf4423be3410ba684c20f8&quot;&gt;How high must one be for the curvature of the earth to be visible to the eye?&lt;/a&gt;, but it doesn't help me just yet. As far as I understand, the above link help calculating the distance to the horizon depending on the altitude. But why is the horizon bent?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would appreciate anyone helping me straighten my thinking :).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The picture:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/utM4U.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/utM4U.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18095" LastActivityDate="2023-04-07T23:28:24.720" Title="Can I see curvature of the Earth on a picture" Tags="|earth-observation|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18261" PostTypeId="2" ParentId="18260" CreationDate="2019-10-20T11:10:39.493" Score="1" Body="&lt;p&gt;A drone can't fly high enough to show the curvature of the Earth. When the Americans were testing German V2 rockets at White Sands in the late forties and early fifties, some reached altitudes of well over 100 miles, but even from that height the curvature of the horizon was barely perceptible. Whatever illusion of a curved horizon you may perceive in your drone photo is only what you would see from a high building.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you can't get to the heights reached by V2 rockets, the best way to see the curvature of the Earth is to watch a tall ship approaching from over the horizon. On a clear day, the tips of the masts or funnels will be visible when most of the ship is hidden by the curvature of the Earth. Likewise when the sun goes down beyond the marine horizon and your town is in twilight, a high flying aircraft overhead will be illuminated by the sun that you can't see because the curvature of the Earth is in the way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From a high building the horizon will appear to curve because it surrounds you in a 360 degree circle, and circles by definition are curved.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-10-20T11:31:35.763" LastActivityDate="2019-10-20T11:31:35.763" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18262" PostTypeId="1" CreationDate="2019-10-20T11:47:08.957" Score="1" ViewCount="62" Body="&lt;p&gt;What is the suitable handheld device to measure the &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CH_4}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{N_2O}$&lt;/span&gt; emissions from the tailpipe of cars? and what the steps to convert the emissions that will measure by the handheld device in unit of (ppm) to the emission factor in unit of (kg/TJ)? &lt;/p&gt;&#xA;" OwnerUserId="18096" LastEditorUserId="2470" LastEditDate="2020-01-05T19:31:04.580" LastActivityDate="2020-01-05T19:31:04.580" Title="Vehicles Emissions" Tags="|climate-change|" AnswerCount="0" CommentCount="3" ClosedDate="2020-01-08T14:30:25.480" ContentLicense="CC BY-SA 4.0" />
  <row Id="18264" PostTypeId="1" CreationDate="2019-10-20T21:53:41.687" Score="3" ViewCount="55" Body="&lt;p&gt;How can I use hyperspectral satellite imagery to remotely detect copper or any prespecified mineral deposit in general?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where can I find a database of the absorption and reflection bands of various ores, and what satellite imagery source could give reliable data?&lt;/p&gt;&#xA;" OwnerUserId="18098" LastActivityDate="2019-11-28T09:03:15.667" Title="Hyperspectral Detection of Ore" Tags="|mineralogy|minerals|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18265" PostTypeId="1" CreationDate="2019-10-21T03:17:31.110" Score="1" ViewCount="109" Body="&lt;p&gt;I am essentially looking for a list of raw datasets without any processing. I can find anomaly datasets, but have had no luck with 100% unprocessed (other than averaging, of course) data. This data is preferably monthly (or less) averaged but it doesn't make that much of a difference to me.  &lt;/p&gt;&#xA;" OwnerUserId="18100" LastActivityDate="2019-10-21T03:17:31.110" Title="Where can I find csv or json data on absolute global average temperature" Tags="|temperature|climate-models|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18266" PostTypeId="1" CreationDate="2019-10-21T05:33:23.027" Score="2" ViewCount="128" Body="&lt;h1&gt;How do we allocate partial CO2 doublings for Empirical Climate Sensitivity? I applied partial doublings on a linear basis, is this correct?&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Climate Threat to the Planet:Implications for Energy Policy and Intergenerational Justice Jim Hansen December 17, 2008&#xA;&lt;a href=&quot;http://www.columbia.edu/~jeh1/2008/AGUBjerknes20081217.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.columbia.edu/~jeh1/2008/AGUBjerknes20081217.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Empirical Climate Sensitivity 3 ± 0.5C for 2 x CO2&lt;/strong&gt;&lt;br&gt; &#xA;(Hanson said it could be 6C in the longer term)&lt;br&gt; &#xA;&lt;a href=&quot;http://www.columbia.edu/~jeh1/2008/TargetCO2_20080407.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.columbia.edu/~jeh1/2008/TargetCO2_20080407.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we assume that the formula above still holds and&lt;br&gt;&#xA;assume the current rate of CO2 increasing at 1.9% per year&lt;br&gt;&#xA;and assume 280 PPM as the CO2 base. &lt;br&gt;&#xA;and assume that partial doublings can be allocated linearly. &lt;br&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Years.......CO2&lt;br&gt;&#xA;From.......Per.......CO2&lt;br&gt;&#xA;Now........Year......Total&lt;br&gt;&#xA;....0..........3.00......410&lt;br&gt;&#xA;....4..........3.17......420.....1.5C&lt;br&gt;&#xA;...17.........4.05......467.....2.0C&lt;br&gt;&#xA;...27.........4.89......513.....2.5C&lt;br&gt;&#xA;...36.........5.80......560.....3.0C&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Keith McClary provided this link, which provided the data below it:&lt;br&gt; &#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_sensitivity#Estimating_climate_sensitivity&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Climate_sensitivity#Estimating_climate_sensitivity&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;IPCC Fifth Assessment Report 2014&lt;/strong&gt;&lt;br&gt;&#xA;&lt;strong&gt;66% likely: Empirical Climate Sensitivity 3 ± 1.5C for 2 x CO2&lt;/strong&gt;&lt;br&gt; &#xA;&lt;strong&gt;Possible: Empirical Climate Sensitivity 1C to 6C for 2 x CO2&lt;/strong&gt;&lt;br&gt; &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;The best information available provided above shows the climate sensitivity. The next thing that we need is the procedure for allocating fractional doubling.&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/sites/2/2019/05/SR15_Chapter1_Low_Res.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ipcc.ch/site/assets/uploads/sites/2/2019/05/SR15_Chapter1_Low_Res.pdf&lt;/a&gt;&#xA;&lt;strong&gt;SPECIAL REPORT: GLOBAL WARMING OF 1.5 ºC&lt;br&gt;&#xA;CH 01&lt;br&gt;&#xA;Framing and Context&lt;/strong&gt;  The following is on page 66&lt;br&gt;&#xA;Expert judgement based on the available evidence (including model simulations, radiative forcing and climate sensitivity) suggests that if all anthropogenic emissions were reduced to zero immediately, any further warming beyond the 1°C already experienced would likely be less than 0.5°C over the next two to three decades, and also likely less than 0.5°C on a century time scale.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;It seems we already missed the 1.5C target:&lt;br&gt; 3 * log2(410/280) degree increase, or about 1.65°C&lt;/h1&gt;&#xA;" OwnerUserId="17970" LastEditorUserId="17970" LastEditDate="2019-10-30T23:30:50.970" LastActivityDate="2019-12-27T19:57:42.257" Title="How do we allocate partial CO2 doublings for Empirical Climate Sensitivity?" Tags="|climate-change|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18267" PostTypeId="2" ParentId="18260" CreationDate="2019-10-21T07:06:36.773" Score="15" Body="&lt;p&gt;Make your own numbers... I will take one sample, just change your figures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have one 4K resolution dron camera. So I can register 3840 x 2160 pixels in one shot.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Considering the Earth as an spherical body, the distance from you to the horizon depends on Earth Radius and your height by:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Distance = (Radius + height) * Sinus {arc-cosinus [Radius / (Radius + height)]}&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So depends on your height:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;| Height (m) | Dist. To Hor. (Km) |&#xA;|:----------:|:------------------:|&#xA;|    1       |         3,6        |&#xA;|    10      |        11,3        |&#xA;|    100     |        35,7        |&#xA;|    1000    |        112,9       |&#xA;|    10000   |        357,1       |&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;My camera have a 24mm focal (on 35mm relative), so in the photograph, I can see 84º degrees. So the distance on between the edges of my horizon is:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;| Height (m) | Dist. To Hor. (Km) | Dist. Edge&amp;lt;&amp;gt;Edge (km) |&#xA;|:----------:|:------------------:|:---------------------:|&#xA;| 1          |         3,6        |          4,8          |&#xA;| 10         |        11,3        |          15,1         |&#xA;| 100        |        35,7        |          47,8         |&#xA;| 1000       |        112,9       |         151,1         |&#xA;| 10000      |        357,1       |         477,9         |&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Once that you have this data, you just need to calculate the arrow of the arc expected:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Arrow Circ. Arc = Radius * Cosinus [ Arc-Sinus (Dist/2/Radius)]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, with this data and the initial data of the camera:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;| Height (m) | Dist. To Hor. (Km) | Dist. Edge&amp;lt;&amp;gt;Edge (km) | Arrow (km) | Curvature (pixel) |&#xA;|:----------:|:------------------:|:---------------------:|------------|-------------------|&#xA;| 1          |         3,6        |          4,8          |    0,000   |         0         |&#xA;| 10         |        11,3        |          15,1         |    0,004   |         1         |&#xA;| 100        |        35,7        |          47,8         |    0,045   |         4         |&#xA;| 1000       |        112,9       |         151,1         |    0,448   |         11        |&#xA;| 10000      |        357,1       |         477,9         |    4,482   |         36        |&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;So finally... If you have a perfect visibility condition, your camera is completely leveled, there is no fish-eye distortion... On a 4K camera at 10 km height, the Earth curvature it will be 2% -&gt; 36 pixels on 3840 pixels wide.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are interested on it, that is not the way. Human eye can not perceive clearly the Earth Sphericity at a commercial flight altitude. So forget your dron, yo should go for a balloon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope it helps!&lt;/p&gt;&#xA;" OwnerUserId="18035" LastActivityDate="2019-10-21T07:06:36.773" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18268" PostTypeId="1" CreationDate="2019-10-21T17:16:57.257" Score="1" ViewCount="379" Body="&lt;p&gt;if we were to send a mission to mars (unlimited budget WE WISH!) to explore different methods that would enable us to thicken the martian atmosphere, what different types of data should this mission capture and how could this help is in exploring potential methods to thicken the martian atmosphere. &lt;/p&gt;&#xA;" OwnerUserId="18103" LastActivityDate="2020-01-05T19:28:01.413" Title="Thickening Mars's Atmosphere" Tags="|atmosphere|mars|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18269" PostTypeId="2" ParentId="18268" CreationDate="2019-10-21T18:54:36.727" Score="1" Body="&lt;p&gt;This is an Earth Science site, not a Mars Science site. However, there will be a manned expedition to Mars within the next 25 years provided a world war doesn't throw a spanner in the works. They won't be exploring methods of thickening the Martian atmosphere, partly because it is impossible to thicken it to any useful degree, by which I mean to a degree which would enable astronauts to wander about in the open without wearing pressure suits.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even if you  could find a way to melt all the &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; in the polar caps (mainly the south pole), there isn't enough to create an atmosphere as substantial as you would find at the top of Mount Everest. There might be enough to raise average temperatures by a few degrees, but what use would that be? The  first astronauts will be doing the usual things. mainly geological exploration, particularly with a view to establishing whether there was ever any primitive, unicellular life on the planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another task will be to find sites which might be suitable for establishing a permanent base, one of the main requirements being a good water supply. They might also experiment with ways of using local materials for building purposes, in preparation for future expeditions building a permanent base. The fact that liquid water can't exist in the open might be a problem when it comes to making cement. The Romans made an excellent cement out of volcanic tuff, so in the right place there could be plenty of that. Measuring the effects of the Martian environment on their bodies will take up much of the astronaut's  time. They will not be exploring methods of geo-engineering. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="2470" LastEditDate="2020-01-05T19:28:01.413" LastActivityDate="2020-01-05T19:28:01.413" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18271" PostTypeId="2" ParentId="18013" CreationDate="2019-10-22T11:56:08.213" Score="1" Body="&lt;p&gt;Orogeny (the building of mountains) is the result of converging plates, but the composition of the resulting mountain range will vary depending on tectonic setting:&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Subduction&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The subduction of an oceanic plate under a continental plate will create a volcanic arc (such as the Andes). This is called an &lt;strong&gt;accretionary orogen&lt;/strong&gt;. Partial melting of the mantle wedge above the subducting plate will generate magma, thus igneous rocks intruding the crust (or erupting at the surface).&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Continental collision&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;This tectonic regime will lead to a &lt;strong&gt;collisional orogen&lt;/strong&gt;. If the crust gets thick enough, the lower crust will partially melt, generating granite plutons. Also, part of the oceanic plate that once existed between the continents can be uplifted onto the crust. That's how today you can find gabbros and pillow lavas in the Alps at 3,000 m a.s.l., while they were formed at an oceanic ridge 2,500 meters below sea level!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So in any case there will be a certain amount of igneous rocks in the core of a given mountain range, even if they might not be exhumed yet.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2019-10-22T11:56:08.213" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18272" PostTypeId="2" ParentId="18268" CreationDate="2019-10-22T12:07:44.557" Score="3" Body="&lt;p&gt;We are already knowledgeable about some aspects of the requirements needed to terraform Mars &amp;amp; the Moon. As @David_Garcia_Bodego mentions in his comments, gravity is a major factor in celestial bodies being able to retain an atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is because the gravity of a celestial body affects the &lt;a href=&quot;https://en.wikipedia.org/wiki/Escape_velocity&quot; rel=&quot;nofollow noreferrer&quot;&gt;escape velocity&lt;/a&gt;  of that body. The other important factor is the surface temperature of the celestial body. This is why &lt;a href=&quot;https://en.wikipedia.org/wiki/Titan_(moon)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Titan&lt;/a&gt;, a satellite of Saturn, has a &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Titan&quot; rel=&quot;nofollow noreferrer&quot;&gt;thick atmosphere&lt;/a&gt;, despite having a similar escape velocity to the Moon (Luna), &lt;a href=&quot;https://physics.stackexchange.com/questions/31909/why-is-titan-able-to-maintain-an-atmosphere-and-not-luna&quot;&gt;it is much colder and has a thick atmosphere&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another factor that assists Titan in maintaining a thick atmosphere is its distance from the Sun and the weaker effect of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_wind&quot; rel=&quot;nofollow noreferrer&quot;&gt;solar wind&lt;/a&gt; at that distance. Also, Titan is protected by &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnetosphere_of_Saturn&quot; rel=&quot;nofollow noreferrer&quot;&gt;Saturn's magnetosphere&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I recommend reading:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://space.stackexchange.com/questions/39474/what-will-happen-to-the-air-released-from-the-moons-surface&quot;&gt;&lt;em&gt;What will happen to the air released from the Moon's Surface?&lt;/em&gt;&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://space.stackexchange.com/questions/12576/could-the-moon-keep-an-atmosphere/12588#12588&quot;&gt;&lt;em&gt;Could the Moon keep an atmosphere?&lt;/em&gt;&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;and the links contained within those questions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, these questions discuss the Moon and not Mars, but the information provided in those questions is applicable to Mars.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_escape&quot; rel=&quot;nofollow noreferrer&quot;&gt;graph&lt;/a&gt; below provides a visual of the gases a celestial body can retain in a atmosphere based on escape velocity and temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XlvLf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XlvLf.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Factors that act in favor of Mars being able to have a thick atmosphere are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Mars is farther away from the Sun than Earth &amp;amp; Luna so it experiences&#xA;a weaker solar wind.&lt;/li&gt;&#xA;&lt;li&gt;The surface temperature of Mars is cold, which reduces the energy of&#xA;atmospheric molecules.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Factors that act against Mars being able to have a thick atmosphere are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The gravity of Mars and subsequently the escape velocity of Mars is small.&lt;/li&gt;&#xA;&lt;li&gt;The lack of a magnetosphere to shield the atmosphere from solar wind.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2019-10-29T02:54:29.967" LastActivityDate="2019-10-29T02:54:29.967" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18273" PostTypeId="1" CreationDate="2019-10-22T14:29:16.167" Score="1" ViewCount="45" Body="&lt;p&gt;This article &lt;a href=&quot;https://www.chemistryworld.com/opinion/the-china-cfc-dilemma/3009280.article?fbclid=IwAR1s-kHINmv4SZYm7-qL3A1uqsjWftYRIP8e8zwBqQ5C7IzF8RV2i-1-yfY&quot; rel=&quot;nofollow noreferrer&quot;&gt;The China CFC dilemma&lt;/a&gt; states CFC emissions now might be 67,000 tonnes per year. I tried to look for how large were the emissions of it before the Montreal Protocol but I couldnt find it.  How large were CFC emissions per year before the Montreal Protocol came into practice? Were they much larger than today's ?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastActivityDate="2019-10-22T15:47:02.657" Title="How large were CFC emissions per year before the Montreal Protocol came into practice?" Tags="|climate-change|climate|ozone|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18275" PostTypeId="1" CreationDate="2019-10-22T19:30:09.627" Score="1" ViewCount="124" Body="&lt;p&gt;I stumbled across a timescale which I am unsure of. What does it mean by intra-daily scale variability? I would also like to know if intra-tidal scale variability is of any use for capturing &lt;strong&gt;daily&lt;/strong&gt; physical processes in estuaries (e.g. stratification). Feedback will help me understand when it is appropriate to use these timescales for making scientific predictions.&lt;/p&gt;&#xA;" OwnerUserId="18112" LastActivityDate="2021-03-17T09:05:00.610" Title="Understanding timescales within the day period" Tags="|oceanography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18276" PostTypeId="2" ParentId="14022" CreationDate="2019-10-23T07:51:48.637" Score="1" Body="&lt;p&gt;Complementing @Gimelist and @Graipher answers... Regarding your title question...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The CERN magnetic field value it is considered on the CERN ring itself, 5 meters away it is just 20mT... It is just physics... just check &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnetic_dipole&quot; rel=&quot;nofollow noreferrer&quot;&gt;this link.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So it is dropping with the inverse cube of the distance.&#xA;On the top of the CERN is becoming... (100 meters away) around 8uT... so just 5 time less that the average Earth Magnetic Field.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consider that the Earth &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnetic_dipole&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dipole&lt;/a&gt; is generated at, minimum, 2890 km from the surface... so if you apply the distance to the field we can detect on the Earth surface (25-65 uT), the dipole on the source should be (average) 962.502.760 million Teslas! (That is not exactly like this, but as approximation)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So a 8.7 Teslas magnet is not affecting, at all, our nearly 1000 billion (international billion, so 10^12) Teslas Earth magnetic field.&lt;/p&gt;&#xA;" OwnerUserId="18035" LastActivityDate="2019-10-23T07:51:48.637" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18277" PostTypeId="2" ParentId="7464" CreationDate="2019-10-23T08:24:28.927" Score="2" Body="&lt;p&gt;It depends...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What do you understand as 24 hours daylight? Sun should be visible? There should be light, even if the Sun is not visible?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are different interpretations:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Astronomical Twilight:Astronomical twilight is the darkest of the 3 twilight phases. It is the earliest stage of dawn in the morning and the last stage of dusk in the evening.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nautical Twilight: Nautical twilight is the second twilight phase. Both the horizon and the brighter stars are usually visible at this time, making it possible to navigate at sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Civil Twilight: Civil twilight is the brightest of the 3 twilight phases. The Sun is just below the horizon, so there is generally enough natural light to carry out most outdoor activities&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if you consider the Civil twilight, at 61º lattitude, you will get one 24 hours daylight. (Close to Helsinki - Finland)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you go to the Nautical one, then you will come south.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Check this &lt;a href=&quot;https://www.timeanddate.com/sun/finland/helsinki&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt;. You will enjoy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope it helps!&lt;/p&gt;&#xA;" OwnerUserId="18035" LastActivityDate="2019-10-23T08:24:28.927" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18278" PostTypeId="1" CreationDate="2019-10-23T08:36:42.553" Score="1" ViewCount="26" Body="&lt;p&gt;And further:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) what qualifies as an &quot;oil-based spray&quot; and at what amount? &#xA;2) does this warning still apply during the rainy season-- when the need for quick cycles of medicines is necessary? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(and yes, I've tried to ask manufacturers but to no avail). &lt;/p&gt;&#xA;" OwnerUserId="13104" LastActivityDate="2019-10-23T08:36:42.553" Title="Why do wettable sulphur manufacturers say never to use it within 30 days of an oil-based spray?" Tags="|agriculture|" AnswerCount="0" CommentCount="5" ClosedDate="2019-10-24T09:48:27.100" ContentLicense="CC BY-SA 4.0" />
  <row Id="18279" PostTypeId="2" ParentId="7283" CreationDate="2019-10-23T09:43:09.750" Score="1" Body="&lt;p&gt;Make your own numbers... I will take one sample with a camera.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let´s say that we have one 4K resolution camera. So we can register 3840 x 2160 pixels in one shot.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Considering the Earth as an spherical body, the distance from you to the horizon depends on Earth Radius and your height by:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Distance = (Radius + height) * Sinus {arc-cosinus [Radius / (Radius + height)]}&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So depends on your height:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;| Height (m) | Dist. To Hor. (Km) |&#xA;|:----------:|:------------------:|&#xA;|    1       |         3,6        |&#xA;|    10      |        11,3        |&#xA;|    100     |        35,7        |&#xA;|    1000    |        112,9       |&#xA;|    10000   |        357,1       |&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;A gran angular camera have a 24mm focal that can see 84º degrees. So the distance on between the edges on the horizon is:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;| Height (m) | Dist. To Hor. (Km) | Dist. Edge&amp;lt;&amp;gt;Edge (km) |&#xA;|:----------:|:------------------:|:---------------------:|&#xA;| 1          |         3,6        |          4,8          |&#xA;| 10         |        11,3        |          15,1         |&#xA;| 100        |        35,7        |          47,8         |&#xA;| 1000       |        112,9       |         151,1         |&#xA;| 10000      |        357,1       |         477,9         |&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Once that you have this data, you just need to calculate the arrow of the arc expected:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Arrow Circ. Arc = Radius * Cosinus [ Arc-Sinus (Dist/2/Radius)]&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, with this data and the initial data of the camera:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;| Height (m) | Dist. To Hor. (Km) | Dist. Edge&amp;lt;&amp;gt;Edge (km) | Arrow (km) | Curvature (pixel) |&#xA;|:----------:|:------------------:|:---------------------:|------------|-------------------|&#xA;| 1          |         3,6        |          4,8          |    0,000   |         0         |&#xA;| 10         |        11,3        |          15,1         |    0,004   |         1         |&#xA;| 100        |        35,7        |          47,8         |    0,045   |         4         |&#xA;| 1000       |        112,9       |         151,1         |    0,448   |         11        |&#xA;| 10000      |        357,1       |         477,9         |    4,482   |         36        |&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;So finally... with a perfect visibility condition, a well leveled camera, no fish-eye distortion... On our 4K camera at 10 km height, the Earth curvature it will be 2% -&gt; 36 pixels on 3840 pixels wide.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Human eye can not perceive clearly the Earth Sphericity at a commercial flight altitude. Around 100 km you can take a picture like the one you show on a super gran angular lens.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope it helps!&lt;/p&gt;&#xA;" OwnerUserId="18035" LastActivityDate="2019-10-23T09:43:09.750" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18280" PostTypeId="2" ParentId="7056" CreationDate="2019-10-23T10:07:58.327" Score="4" Body="&lt;p&gt;If you can get one dumpy level (surveyor level), it is very easy.&lt;/p&gt;&#xA;&lt;p&gt;Place the dumpy level in one flat area and take the level from one point and transfer to another one. Try to do it as far as possible. At this stage it is suppose that you have 2 points on the same level.&lt;/p&gt;&#xA;&lt;p&gt;Then place the dumpy level as close as you can to one of this points and transfer again.&lt;/p&gt;&#xA;&lt;p&gt;You will get a deviation of 1.5 mm at 100 meters.&lt;/p&gt;&#xA;&lt;p&gt;Why? The Earth is an spherical body so the gravity is radial. The gravity in one point have no the same direction that the gravity at 100 meters...&lt;/p&gt;&#xA;&lt;p&gt;How can you explain this gravity deviation on a flat body?&lt;/p&gt;&#xA;&lt;p&gt;The funny issue is that it happens in the complete planet... How flat-Earth defendors can explain it?&lt;/p&gt;&#xA;&lt;p&gt;Yo can do the same issue with a laser level, even, with a hand level and one laser pointer.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/z6AQ0.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/z6AQ0.png&quot; alt=&quot;Figure&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;On a flat earth, pendulus will maintain its normal direction, on a rounded Earth, this normal direction is changing as well as the difference of elevation between 2 points, as the pendulus become tilted.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/N1g3Z.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/N1g3Z.gif&quot; alt=&quot;Automatic level&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Regarding this 1.5 mm every 100 meters... Mathematics: 100 meters * Atan (100 m / 6370000 m). Assuming an average radius of 6370 km for Earth, every 100 meters at the surface you are tilting the gravity 1.5 mm from the gravity 100 meters away in any direction. This phenomena it is registered in the whole planet.&lt;/p&gt;&#xA;" OwnerUserId="18035" LastEditorUserId="18035" LastEditDate="2023-03-12T02:36:16.010" LastActivityDate="2023-03-12T02:36:16.010" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18281" PostTypeId="1" CreationDate="2019-10-23T19:08:25.400" Score="2" ViewCount="45" Body="&lt;p&gt;This question might turn out to be more about physics then geology so apologies in advance if that is the case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Years ago I read something that said in crystals &quot;atoms have finite positions along the crystal lattice.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I took that to mean was that in any crystal structure, atoms have a finite number of possible positions. Which is what I want to find out here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;After searching images for crystalline structures I found that all of them represent atoms as tiny balls that line up perfectly in a regular pattern.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/W4zZu.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/W4zZu.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I take all this to mean is that, in a crystal structure, atoms can only exist in very specific places in accordance with their patterns like a cube made out of Lego bricks. They can only exist in, for want of a better word, a digital fashion. They always form straight edges and if another atom is added, it's like another Lego brick has been added to the cube, it can only be fitted in exactly according to its grid like structure. The atom can only be in column one row six or column three row four and so on. Like pixels on the screen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LoqJM.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LoqJM.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My understanding is that, in a crystal lattice, atoms cannot take positions in an analogue way, they cannot be positioned in a lattice a few micro metres one way or the other. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I conclude from this reasoning is that there is only a finite number of shapes that any crystalline material can take because of the digital nature of the positioning of the atoms, as opposed to the analogue way you can sculpt plasticine.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this so?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we could shrink down to the atomic level and look at a crystalline solid with the entire structure look like a Lego sculpture or a pixelated image? Or do the atomic patterns allow for some degree of analogue placement?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have read there is such a thing as screw dislocations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2BXQ0.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2BXQ0.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does this say that although crystal atoms do generally have a pattern, that pattern is not rigid and inflexible?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you pour liquid glass into a spherical mould and let it cool or sculpt something out of clay and fire it, do the crystal lattices that form bend to accommodate these curved edges? Or is the solid still cubic in pattern and it just seems to be analogue because it's too small to be seen? Do screw defects only occur when someone or something is applied pressure to the crystal or do they naturally form with curved lattices?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And yes I'm aware crystal grains have non-latticed atoms between them and sometimes there is a missing atom in the lattice. But that's not what I'm talking about here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To put it as simply as I can, to crystals onlay ever exist as lego scuptures or can the grow like trees with curved bows?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: when I say crystals I mean crystals like what we call in every day life like pyrite and quartz, materials like stone and ceramics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you for your attention.&lt;/p&gt;&#xA;" OwnerUserId="18116" LastEditorUserId="18116" LastEditDate="2019-10-24T19:37:05.510" LastActivityDate="2019-10-24T19:37:05.510" Title="Can crystal lattices be analogue?" Tags="|mineralogy|crystals|crystallography|" AnswerCount="0" CommentCount="2" ClosedDate="2019-10-29T06:04:52.810" ContentLicense="CC BY-SA 4.0" />
  <row Id="18282" PostTypeId="2" ParentId="7056" CreationDate="2019-10-24T00:05:45.407" Score="3" Body="&lt;p&gt;There are some recommendations in the following videos: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=XHBZkek8OSU&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Nightly Show - Neil deGrasse Tyson Slams Flat-Earth Theorist B.o.B&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=TibLAysPvfA&quot; rel=&quot;nofollow noreferrer&quot;&gt;Neil deGrasse Tyson Rips Kyrie Irving's Flat Earth Nonsense | TMZ Sports&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;and especially&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=hLPPE3_DVCw&quot; rel=&quot;nofollow noreferrer&quot;&gt;Neil Tyson Demonstrates Absurdity of &quot;Flat Earth&quot;&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;which includes suggestions like &lt;a href=&quot;https://en.wikipedia.org/wiki/Eratosthenes#Measurement_of_the_Earth&amp;#39;s_circumference&quot; rel=&quot;nofollow noreferrer&quot;&gt;repeat Eratosthenes' experiment&lt;/a&gt; using three wells instead of two&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BgpIU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BgpIU.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;watch an eclipse&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bskhw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bskhw.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;or watch a ship sail off into the distance slowly drop below the horizon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Bh83J.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Bh83J.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2019-10-24T00:05:45.407" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18283" PostTypeId="2" ParentId="18275" CreationDate="2019-10-24T06:11:33.423" Score="1" Body="&lt;p&gt;Intra-daily scale variability is pointing to the circadian rhythms. the circadian rhythms are physical, mental, and behavioral changes that follow a &quot;daily&quot; cycle. They respond primarily to light and darkness in an organism's environment. It is not an accurate time scale, as the light and darkness are not a cycle itself, but it is commonly use on medicine. Google it. I will recommend &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5533453/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Intra-tidal it is used for a few processes linked with the tides, but it is not &quot;just&quot; on daily basis as the tides have not a daily interval. Look &lt;a href=&quot;https://en.wikipedia.org/wiki/Tide&quot; rel=&quot;nofollow noreferrer&quot;&gt;there&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Lunitidal_interval&quot; rel=&quot;nofollow noreferrer&quot;&gt;there&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Both timescales are usefull for whatever process linked to human (or animal) bodies and tides. But as scale times, they are not very useful.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding predictions... which kind of predictions are you talking about?&lt;/p&gt;&#xA;" OwnerUserId="18035" LastActivityDate="2019-10-24T06:11:33.423" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18284" PostTypeId="1" AcceptedAnswerId="18285" CreationDate="2019-10-24T11:01:00.900" Score="3" ViewCount="616" Body="&lt;p&gt;We know that our earth's core is made up of iron-nickel alloy, and it is spinning to create magnetic flux all around our planet to create our life-saving Magnetosphere. And this also influences our 9.8 m/s gravitational force, I think. So what if Earth's core (both inner-solid and outer-liquid) was made up of copper or any other metals? How would the magnetosphere and gravitational force differ from ours?&lt;/p&gt;&#xA;" OwnerUserId="18118" LastEditorUserId="20607" LastEditDate="2023-10-15T22:12:53.813" LastActivityDate="2023-10-20T01:56:28.967" Title="If the Earth's core were made up of copper/other metals other than iron-nickel alloy, what would the magnetosphere be like?" Tags="|mineralogy|core|geomagnetism|gravity|magnetosphere|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18285" PostTypeId="2" ParentId="18284" CreationDate="2019-10-24T12:45:31.160" Score="3" Body="&lt;p&gt;On a quick approach:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Magnetism. The copper itself have a weak magnetism, so a copper core will not create a magnetosphere. &lt;a href=&quot;https://www.popularmechanics.com/science/a15902858/copper-strong-magnets/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chek here&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnetism&quot; rel=&quot;nofollow noreferrer&quot;&gt;here.&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Gravity. The Iron density is 7.874 g/cm³ and the nickel density is 8.908 g/cm³. Copper density is 8.96 g/cm³. So with those density data, the core will be heavier. (The actual core is supposed to have a &lt;a href=&quot;https://en.wikipedia.org/wiki/Structure_of_the_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;9.9-12 g/cm³&lt;/a&gt; density) It is supposed that this additional mass will increase the gravity. What it is not well determine is the % of iron and nickel at the core, so, we can talk on probably a raising on between 5-15% the actual gravity force.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Regarding some other metals, it will depends on magnetism and density.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope it helps!&lt;/p&gt;&#xA;" OwnerUserId="18035" LastActivityDate="2019-10-24T12:45:31.160" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18286" PostTypeId="1" CreationDate="2019-10-24T13:40:31.227" Score="3" ViewCount="501" Body="&lt;p&gt;&amp;quot;Everybody knows&amp;quot; that Newton and Kepler calculated the age of the Earth. My problem is that, whilst &amp;quot;everybody knows&amp;quot; this, no-one gives a reference that I can read for myself.&lt;/p&gt;&#xA;&lt;p&gt;If, for example, I want to read what Thomas Burnett believed, I download a copy of Telluris Theoria Sacra and I can read for myself that he accepted the reality of Noah's flood. The same is true of St Augustine's beliefs as there are several online translations of City of God Against the Pagans.&lt;/p&gt;&#xA;&lt;p&gt;But Newton and Kepler?&lt;/p&gt;&#xA;&lt;p&gt;Zilch. Sweet F.A. Absolutely nothing.&lt;/p&gt;&#xA;&lt;p&gt;Even when a website  references a text, either I can't find the text, or there is no age-of-the-earth calculation in the text that I can find.&lt;/p&gt;&#xA;&lt;p&gt;So, did either Newton or Kepler calculate the age of the earth, or is this just an urban myth? If it's true, does anyone have references that I can look at for myself. These will have to be secondary references (English translations) as I expect the actual primary reference to be in Latin, and sadly, I only read English.&lt;/p&gt;&#xA;" OwnerUserId="18121" LastEditorUserId="2470" LastEditDate="2023-02-27T03:51:07.327" LastActivityDate="2023-02-28T01:18:13.850" Title="References for Newton's &amp; Kepler's age of the Earth calculations" Tags="|geochronology|history-of-science|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18287" PostTypeId="1" AcceptedAnswerId="18289" CreationDate="2019-10-24T13:51:58.683" Score="19" ViewCount="5636" Body="&lt;p&gt;There is a conflict between Egypt and Ethiopia, because the latter wants to build a dam on the Nile river. Citing &lt;a href=&quot;https://www.aljazeera.com/news/2019/10/ethiopia-nobel-prize-winning-leader-issues-warning-dam-191022141801474.html&quot; rel=&quot;noreferrer&quot;&gt;this article&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;[Egypt] fears the Nile dam will reduce its share of the river and leave the&#xA;  country with dwindling options as it seeks to protect its main source&#xA;  of fresh water.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What do they mean by &quot;reduce its share of the river&quot;? As far as I understand, the dam will create a reservoir, which will initially divert some water to be filled, but once that is done, the flow of the river should be the same. Is Egypt worried about this initial reduction, or do dams somehow reduce the flow of a river?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If so, what is the mechanism? I would guess that this is due to increased evaporation from the river, since the reservoir has a bigger surface than the usual river, but then again, it also collects more rain.&lt;/p&gt;&#xA;" OwnerUserId="7522" LastActivityDate="2019-10-24T22:07:07.367" Title="Do dams reduce the flow of river downstream?" Tags="|hydrology|rivers|dams|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18288" PostTypeId="2" ParentId="18286" CreationDate="2019-10-24T15:52:21.557" Score="3" Body="&lt;p&gt;Your question may be better suited to either SE History or SE History of Science and Mathematics. The date of the so called creation of the Earth has nothing to do with Earth Science.&lt;/p&gt;&#xA;&lt;p&gt;For Kepler I found he wrote the book &lt;em&gt;&lt;a href=&quot;https://www.science20.com/science_20/kepler_young_earth_creationist-134613&quot; rel=&quot;nofollow noreferrer&quot;&gt;KANONES PUERILES&lt;/a&gt;&lt;/em&gt;, in it he calculates the creation date to be 27 April 4997 BC.&lt;/p&gt;&#xA;&lt;p&gt;The published works of &lt;a href=&quot;https://en.wikipedia.org/wiki/Isaac_Newton&quot; rel=&quot;nofollow noreferrer&quot;&gt;Newton&lt;/a&gt; reveal little. Some authors on Newton mention an unpublished document he wrote in either 1704 or 1705. Any calculations he may have done regarding the so called date of creation may be in his unpublished writings.&lt;/p&gt;&#xA;&lt;p&gt;You may need to review the bibliographies of authors who wrote biographies on Newton, such the 1855 book by Sir David Brewster, &lt;a href=&quot;https://thenaturalhistorian.com/2012/08/03/isaac-newton-mosaic-account-of-creation-burnet-theory-earth/&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Memoirs of the Life, Writings, and discoveries of Sir Isaac Newton, volume 2&lt;/em&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Alternatively you can search &lt;a href=&quot;https://www.lib.cam.ac.uk/collections/departments/manuscripts-university-archives/significant-archival-collections/papers-sir&quot; rel=&quot;nofollow noreferrer&quot;&gt;Newton's papers at the University of Cambridge&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2023-02-27T04:19:59.147" LastActivityDate="2023-02-27T04:19:59.147" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18289" PostTypeId="2" ParentId="18287" CreationDate="2019-10-24T16:19:23.723" Score="19" Body="&lt;p&gt;Once a dam has been constructed in a river, the &lt;em&gt;natural flow&lt;/em&gt; of water will be disrupted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You correctly state that initially there will be a period required for the dam to fill. Until then, little of no water will flow beyond the dam.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Dams are created for one or more of three reasons:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;To supply potable water to a population of humans for domestic or&#xA;industrial purposes.&lt;/li&gt;&#xA;&lt;li&gt;For agricultural purposes.&lt;/li&gt;&#xA;&lt;li&gt;To generate hydro-electricity.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Water released from a dam prior to it being full may be to restore some flow for environmental reasons, because hydro electricity may need to be generated or it may be needed for agricultural reasons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To protect dams from overfilling and damaging the dam wall spillways are generally constructed to allow the excess water to flow beyond the dam. For dams without a spillway, the dam gates will be opened to reduce the amount of water in the dam to protect the dam from failure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the issues with dams is they prevent sediment carried by the river to travel the full length of the river. This can be detrimental to the natural replenishment of some farmlands of nutrient rich sediment and it is detrimental to the replenishment of nutrients to fish breeding regions near the mouths of rivers. This happened when the Egyptians built the &lt;a href=&quot;https://en.wikipedia.org/wiki/Aswan_Dam&quot; rel=&quot;noreferrer&quot;&gt;Asswan Dam&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other issue with dams is that people downstream of the dam cannot rely of the natural flow of the river, in terms of timing of flows and quantities of flow. This is the main concern for Egypt. It relies heavy on the Nile River as its main source of fresh water for hydro-electricity generation, agriculture and water for people to drink.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-10-24T16:19:23.723" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18290" PostTypeId="2" ParentId="18287" CreationDate="2019-10-24T17:07:42.203" Score="14" Body="&lt;p&gt;You're correct that simply putting a dam in place, once its lake is filled, doesn't change the &lt;em&gt;average&lt;/em&gt; flow downstream by more than a few percent (those few percent &lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-15-00224.1&quot; rel=&quot;noreferrer&quot;&gt;can be lost&lt;/a&gt; to increased evaporation). However,&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Many dam systems are used to abstract water from the river for irrigation and other uses, sometimes on a very large scale. This does reduce the average flow downstream.&lt;/li&gt;&#xA;&lt;li&gt;Depending on the site, filling the lake might take a year or more, which could have severe consequences on people downstream.&lt;/li&gt;&#xA;&lt;li&gt;More generally, dams allow regulation of the downstream flow. This is a major reason for their construction, in areas that want to smooth out a flood/drought cycle. But it means that downstream water supply is then under the control of the dam operators, which may be objectionable to people downstream - especially when the river crosses international borders. The water must be released eventually, but the upstream operator could choose to (for example) withhold it for the growing season and cause crop failure that year.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;For all of these reasons, river management is a common subject of international treaties. I don't know the details of this particular case involving Ethiopia and Egypt, but I imagine that the main concern is probably about water abstraction. If Ethiopia takes water for drinking, irrigation, etc., then that's less water left for Egypt.&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2019-10-24T22:07:07.367" LastActivityDate="2019-10-24T22:07:07.367" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18291" PostTypeId="2" ParentId="18286" CreationDate="2019-10-24T18:33:49.277" Score="0" Body="&lt;p&gt;I have never heard that Newton or Kepler calculated the age of the Earth, so I think it is most probably an urban myth. What I can tell you is that if they did any such calculation it must have been hopelessly inaccurate. In the 17th century, Archbishop Usher calculated the age of the Earth from Biblical sources and decided it was about 6,000 years old. In the mid-nineteenth century, Lord Kelvin, an eminent physicist, made a calculation based on how long it would take to cool down to its present temperature from an incandescent state, and came to the conclusion that it was about 100,000,000 years old.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although he did better than Archbishop Usher, the reason for Lord Kelvin's inaccuracy was that in his day the atom and radioactivity were a closed book, so he couldn't take radioactive decay into account when doing his calculations. Radioactive decay not only keeps the Earth's interior hot, but enables us to measure the age of the Earth with reasonable accuracy. The decay of uranium to lead in zircons from very ancient rocks tells us that the Earth is about  4.5 billion years old.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-10-25T10:19:43.820" LastActivityDate="2019-10-25T10:19:43.820" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18292" PostTypeId="1" CreationDate="2019-10-25T00:16:33.877" Score="2" ViewCount="149" Body="&lt;p&gt;I am doing a capstone project for a sensor systems course and I would like to write  a python program to acquire, process and present seismic data like that of seismic surveys. Is it possible using just an Arduino and an accelerometer? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have access to the following accelerometer:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;SparkFun Triple Axis Accelerometer Breakout - MMA8452Q &lt;/p&gt;&#xA;" OwnerUserId="18117" LastActivityDate="2019-11-24T10:00:50.063" Title="Using an accelerometer as a geophone to conduct a seismic survey" Tags="|seismology|seismic|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18293" PostTypeId="2" ParentId="18292" CreationDate="2019-10-25T09:44:21.233" Score="1" Body="&lt;p&gt;Accelerometers have already been used for acquiring seismic data in a lot of studies: see &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6679216/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this review&lt;/a&gt;, and references therein.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the code part, there is a Python framework for seismology: &lt;a href=&quot;https://github.com/obspy/obspy/wiki&quot; rel=&quot;nofollow noreferrer&quot;&gt;ObsPy&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2019-10-25T09:44:21.233" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18294" PostTypeId="2" ParentId="2644" CreationDate="2019-10-25T12:52:25.787" Score="6" Body="&lt;p&gt;Massive, caldera-forming eruptions like the one at Toba usually happen at large silicic systems. At such systems, we expect a surface uplift as the pressure builds in the magma reservoir. This can be measured by radar interferometry (InSAR) and/or GPS. It is the case at Laguna del Maule volcano (Chile), were uplit up to 28 cm per year has been measured by InSAR (&lt;a href=&quot;https://academic.oup.com/gji/article/196/2/885/577558&quot; rel=&quot;nofollow noreferrer&quot;&gt;Feigl et al. 2014&lt;/a&gt;). A similar pattern would be observed at Toba if a magma reservoir was being replenished. However:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;We don't know the timescale needed for overpressure, thus eruption, of the reservoir. It depends on many parameters, such as reservoir size and depth, strength of host rock, rate of fresh magma supply...&lt;/li&gt;&#xA;&lt;li&gt;We don't even know if such uplift will lead to an eruption. The magma could very well be intruded into the crust (in the form of dikes and sills), releasing the pressure in the reservoir. The uplift would then cease without an eruptive crisis.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit&lt;/strong&gt; &lt;span class=&quot;math-container&quot;&gt;$-$&lt;/span&gt; Two new studies about the Laguna del Maule volcanic field:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1029/2020JB019449&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bai et al. (2020)&lt;/a&gt; used seismic data to image the crust below, finding a superficial zone with an estimated 70 km&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt; of magma.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1007/s00445-021-01457-0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Le Mével et al. (2021)&lt;/a&gt; used GPS and InSAR data to model surface uplift, finding an acceleration of uplift rate in recent years.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Again, this does not mean that the system is going to erupt anytime soon. But if the Toba magmatic system was being replenished, we would expect to measure similar ground displacement.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2021-09-13T12:11:45.303" LastActivityDate="2021-09-13T12:11:45.303" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18295" PostTypeId="2" ParentId="18035" CreationDate="2019-10-25T13:24:47.067" Score="5" Body="&lt;p&gt;To complete Gimelist's answer: many silicic domes and flows lie right on top of a tephra layer with the same age and composition. See for instance this classic paper of &lt;a href=&quot;https://doi.org/10.1130/0016-7606(1983)94&amp;lt;362:SAEOAR&amp;gt;2.0.CO;2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fink (1980)&lt;/a&gt; about Little Glass Mountain. This is interpreted as follow: a gas-rich magma ascends into a conduit and, because of its high volatile content, fragments, leading to an explosive eruption. The vent opening allows the rest of the magma to degas: it erupts effusively. Hence the lava flow or dome is emplaced on the tephra layer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In 2011-2012, there was an eruption at Cordon Caulle (Chile) that showed that both dynamics can even happen at the same time! There was magma explosion and effusion from the same vent, simultaneously. This is explained by &lt;a href=&quot;https://doi.org/10.1007/s00445-013-0702-9&quot; rel=&quot;nofollow noreferrer&quot;&gt;Castro et al. (2013)&lt;/a&gt; by a dyke geometry (figure 7) allowing some magma to ascend more slowly, thus having more time to degas. &lt;a href=&quot;https://doi.org/10.1016/j.jvolgeores.2013.06.005&quot; rel=&quot;nofollow noreferrer&quot;&gt;Schipper et al. (2013)&lt;/a&gt; also proposed a conduit model (figure 10) where shear zonation creates a network of permeable magma through which the explosive activity occurs.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2020-01-15T10:15:25.617" LastActivityDate="2020-01-15T10:15:25.617" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18297" PostTypeId="2" ParentId="14854" CreationDate="2019-10-25T14:18:04.750" Score="2" Body="&lt;p&gt;Intra-plate volcanism occurs when rifting of the plate occurs. But you don't necessarily need a hotspot (or rather a mantle plume) to trigger a rifting process. There are two types of rifting:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Active rifting&lt;/strong&gt;, which indeed implies the rise of a mantle plume under the lithosphere. This yields to the bulging of the lithosphere, then to its extension. In such systems, volcanism usually happens early, while sedimentation happens at a later stage. Example: the East African rift.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Passive rifting&lt;/strong&gt;. In this system, the extension of the lithosphere is triggered only by the stress at the plate boundaries. This extension allows the asthenosphere to rise passively. In this case the sedimentation in the basin happens before the volcanism. Example: the Rio Grande rift.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Note that nature does not comply with these idealized models! In French Massif Central, there is evidence for a two-stage rifting, first passive then active. &lt;a href=&quot;https://hal.univ-reunion.fr/hal-01391920/document&quot; rel=&quot;nofollow noreferrer&quot;&gt;Merle and Michon (2001)&lt;/a&gt; proposed a model where the formation of the Alps lithospheric root induces an asthenospheric flow, leading to this two-stage rifting with no proper mantle plume involved.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2019-10-25T14:18:04.750" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18298" PostTypeId="1" CreationDate="2019-10-25T21:16:49.457" Score="2" ViewCount="332" Body="&lt;p&gt;How can we accurately quantify the degree of scientific certainty that global heating is caused by humans?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seem virtually certain that the huge 100 ppm spike in &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; since 1950 can only be caused by humans. Can we be as sure that this huge spike in &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; caused the 1 &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{^o}$&lt;/span&gt;C increase in global temperatures as we are that tobacco causes cancer? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do validated alternative explanations exist?&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;What kinds of objective measures are typically used to determine the specific degree of scientific certainty?&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/A0eOU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/A0eOU.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wei6D.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wei6D.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;There is a trend showing an increasing slope in the following graph data&lt;/strong&gt;&lt;br&gt;&#xA;1910 to 1960---0.41---50 years / 0.41 = &lt;strong&gt;122 years per degree&lt;/strong&gt;&lt;br&gt;&#xA;1960 to 2018---1.03---58 years / 0.87 =  &lt;strong&gt;67 years per degree&lt;/strong&gt;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://data.giss.nasa.gov/gistemp/graphs/graph_data/Global_Mean_Estimates_based_on_Land_and_Ocean_Data/graph.txt&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://data.giss.nasa.gov/gistemp/graphs/graph_data/Global_Mean_Estimates_based_on_Land_and_Ocean_Data/graph.txt&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sXH4u.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sXH4u.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;I am trying to point out exactly how implausible global heating NOT CAUSED BY BY HUMANS really is to skeptical minds that are not very good with science.&lt;/h1&gt;&#xA;" OwnerUserId="17970" LastEditorUserId="2470" LastEditDate="2020-01-05T19:14:53.653" LastActivityDate="2020-01-05T19:14:53.653" Title="How can we accurately quantify the degree of scientific certainty that global heating is caused by humans?" Tags="|climate-change|" AnswerCount="2" CommentCount="19" ContentLicense="CC BY-SA 4.0" />
  <row Id="18299" PostTypeId="2" ParentId="18298" CreationDate="2019-10-25T22:19:42.467" Score="-8" Body="&lt;p&gt;No, it is not possible to establish a human cause with the degree of certainty you are asking for. There have been similar episodes in the distant past when either there were no humans at all, or the total emissions of all the worlds cooking fires were comparable with the emissions of one solitary and unremarkable volcano  If global heating with humans as the sole cause were as certain as the existence of gravity, there would be no controversy or debate about it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What can be established with certainty is that since the industrial revolution got well under way there has been a fairly substantial ppm rise in atmospheric CO2, and this has coincided with a small but measurable rise in global temperature. Whether this is entirely coincidence or whether it is cause and effect is hotly debated, and there is not unanimous agreement even among professional meteorologists and climatologists. There was already some global warming (called an interglacial) long before the industrial revolution added some extra CO2 to the atmosphere, but most scientists think this additional CO2 has accelerated global warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are natural mechanisms which extract CO2 from the atmosphere, and these natural mechanisms are very slightly more effective when CO2 content increases. However, if the increase is too rapid it can be more than these natural mechanisms can deal with. Climate change is a natural phenomenon which has been under way for the past 4.5 billion years and is likely to continue for as long as the world exists.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-10-25T22:52:19.820" LastActivityDate="2019-10-25T22:52:19.820" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18300" PostTypeId="2" ParentId="2734" CreationDate="2019-10-26T13:02:34.717" Score="1" Body="&lt;p&gt;The Mercator Projection has been used and it is used since the XVI century due to it maintain the course, rhumb or route. So it is useful for navigation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the Earth is approached by a ellipsoid, then you get the formulas that you saw on &lt;a href=&quot;https://en.wikipedia.org/wiki/Mercator_projection&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mercator Projection.&lt;/a&gt; This transformation it is complicated for a ellipsoid, as the Earth curvature it is not a constant, so in the example you gave (moving 300m eastwords, or 400m northwards), you need to transform the first point from geographical coordinates to rectangular coordinates, then shift the point 300 meters east, check the correction on distance due to the different curvature on each point, apply the correction, then shift the point 400 meters northwards, check the correction, apply the correction and bring the coordinates back to geographical coordinate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is to much computing time and there are a lost of precision loss on the different shiftings and transformation geographical &amp;lt;-&gt; rectangular coordinates. &lt;a href=&quot;https://en.wikipedia.org/wiki/Web_Mercator_projection&quot; rel=&quot;nofollow noreferrer&quot;&gt;Web Mercator&lt;/a&gt; is just a Mercator that considers the Earth approach by an sphere, not a ellipsoid. That is much easier, needs less computation as, the curvature in a sphere is constant it is not required to consider. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mercator projection is ok for navigation (that is what you are doing with Google Earth or Google Maps). Check this &lt;a href=&quot;https://gis.stackexchange.com/questions/48949/epsg-3857-or-4326-for-googlemaps-openstreetmap-and-leaflet&quot;&gt;link.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding the constants... &lt;code&gt;a&lt;/code&gt; is the semi-major axis of an ellipsoid, &lt;code&gt;amap&lt;/code&gt; is the semi-major axis on the map (as the Mercator Projection is distorting the distances, you should make a distance correction, that it is become bigger as far as you are from the Equator) &lt;code&gt;e&lt;/code&gt; is the eccentricity of the ellipsoid. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding the latitude issue... Thing a little bit on this question: In the Mercator Projection it is consider, as Earth approach a sphere and a revolution ellipsoid. Both surfaces are revolution surfaces so, there is no variation along the longitude way. That is why the longitude is not required for Y calculation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyhow, is something is not clear, just let me know. Hope it helps!&lt;/p&gt;&#xA;" OwnerUserId="18035" LastActivityDate="2019-10-26T13:02:34.717" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18301" PostTypeId="1" CreationDate="2019-10-26T17:33:08.833" Score="1" ViewCount="170" Body="&lt;p&gt;I notice on a website talking about the jet stream &lt;a href=&quot;https://www.weather.gov/jetstream/jet&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.weather.gov/jetstream/jet&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The winds blow from west to east in jet streams but the flow often shifts to the north and south. Jet streams follow the boundaries between hot and cold air. Since these hot and cold air boundaries are most pronounced in winter, jet streams are the strongest for both the northern and southern hemisphere winters.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Why are these hot and cold air boundaries mostly pronounced in winter?&lt;/p&gt;&#xA;" OwnerUserId="18137" LastEditorUserId="2470" LastEditDate="2019-10-27T03:39:58.073" LastActivityDate="2019-10-27T03:39:58.073" Title="Why is the jet stream stronger in winter?" Tags="|jet-stream|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18302" PostTypeId="2" ParentId="18301" CreationDate="2019-10-26T18:48:32.643" Score="1" Body="&lt;p&gt;Because in summer the Arctic and sub-Arctic are quite warm, some days even hot, so winds blowing north from the Med or North Africa will not produce so great a contrast as they would in the winter. The reason for the Arctic's hot summers is that for a while the sun is in the sky 24 hours a day.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-10-26T18:48:32.643" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18303" PostTypeId="2" ParentId="18301" CreationDate="2019-10-26T21:41:30.400" Score="3" Body="&lt;p&gt;I'll look at the climates of the town of &lt;a href=&quot;https://en.wikipedia.org/wiki/Inuvik#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Inuvik&lt;/a&gt; In Canada's Northwest Territory at a latitude of 68°21′42″N against that of &lt;a href=&quot;https://en.wikipedia.org/wiki/Mexico_City#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mexico City&lt;/a&gt; at a latitude of 19°26'N. In July, the daily mean temperatures are 14.1°C in Inuvik and 18.2°C in Mexico City — a difference of 4.1°C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Compare that small difference with the daily mean temperatures in January of -26.9°C in Inuvik and 14.6°C in Mexico City – a huge difference of 41.5°. That factor of ten increase in the temperature difference in winter over summer drives a lot more north-south circulation in the winter compared to the summer, which in turn makes the jet streams stronger in winter compared to summer.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2019-10-26T21:41:30.400" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18305" PostTypeId="1" CreationDate="2019-10-27T13:09:35.227" Score="2" ViewCount="228" Body="&lt;p&gt;I am building a garden calendar app, that uses the average temperature for each month to create a calendar. Are there websites that allow me to easily download this data in json format?&lt;/p&gt;&#xA;" OwnerUserId="18140" LastEditorUserId="6016" LastEditDate="2021-02-04T22:33:32.353" LastActivityDate="2021-02-05T04:01:33.567" Title="Is there a website where I can freely download monthly average temperatures per city?" Tags="|temperature|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18306" PostTypeId="2" ParentId="2734" CreationDate="2019-10-27T16:13:06.453" Score="1" Body="&lt;p&gt;Google's &quot;Web Mercator&quot; projection  is a very different beast from the Mercator projection. The former provides a coordinate system for the area you are viewing, oriented in the way you rotated the view.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The formulas you put in your original question are probably more computationally efficient when used for this purpose, but they do &lt;strong&gt;not&lt;/strong&gt; foster understanding. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact, those formulas are obfuscatory, since they include an &lt;a href=&quot;https://en.wikipedia.org/wiki/Eccentricity_(mathematics)&quot; rel=&quot;nofollow noreferrer&quot;&gt;eccentricity&lt;/a&gt; term &lt;span class=&quot;math-container&quot;&gt;$e$&lt;/span&gt; (this is &lt;strong&gt;not&lt;/strong&gt; the base of the natural logarithms), but Google uses a spherical model where &lt;span class=&quot;math-container&quot;&gt;$e=0$&lt;/span&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The letter &lt;span class=&quot;math-container&quot;&gt;$a$&lt;/span&gt; (the one without the subscript) is typically used for an ellipsoid's &lt;a href=&quot;https://en.wikipedia.org/wiki/Semi-major_and_semi-minor_axes&quot; rel=&quot;nofollow noreferrer&quot;&gt;semimajor axis&lt;/a&gt; (for Earth this is about 6378 km depending on the geodetic model used). When &lt;a href=&quot;https://en.wikipedia.org/wiki/Spherical_cow&quot; rel=&quot;nofollow noreferrer&quot;&gt;assuming a spherical Earth&lt;/a&gt;, use &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; instead, to refer to Earth's &quot;radius&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$a_{map}$&lt;/span&gt;, on the other hand, is the map scale, the desired ratio between distances between points on the ground and their corresponding points on the map. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Notice that the equations you provide give &lt;a href=&quot;https://en.wikipedia.org/wiki/Derivative&quot; rel=&quot;nofollow noreferrer&quot;&gt;derivatives&lt;/a&gt;, that is, the rate of change of one parameter based on another. They give &lt;span class=&quot;math-container&quot;&gt;$dx/dE$&lt;/span&gt; and  &lt;span class=&quot;math-container&quot;&gt;$dy/dN$&lt;/span&gt; instead of &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$y$&lt;/span&gt;. E and N are the coordinates derived by rotating and aligning the Earth to your view. Because Google assumes a sphere, you can get them by running the latitude and longitude through  an &lt;a href=&quot;https://en.wikipedia.org/wiki/Azimuthal_equidistant_projection&quot; rel=&quot;nofollow noreferrer&quot;&gt;azimuthal equidistant&lt;/a&gt; projection with the given center and rotation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Mercator projection is a &lt;a href=&quot;http://www.geography.hunter.cuny.edu/~jochen/GTECH361/lectures/lecture04/concepts/Map%20coordinate%20systems/Cylindrical%20projections.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;cylindrical&lt;/a&gt; one, that is, the coordinate system is developed by wrapping a cylinder around the Earth, projecting its features onto the cylinder, and then unrolling the cylinder to lie flat. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This causes the lines of latitude and longitude to form a rectangular grid. In such a projection, the ratio between the final x coordinate and the longitude is a constant. This constant is &lt;span class=&quot;math-container&quot;&gt;$a*a_{map}$&lt;/span&gt; using the notation from the original question. Thus, changes in scale do not depend on the longitude, so longitude does not appear in the formulas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's also a &lt;a href=&quot;https://en.wikipedia.org/wiki/Conformal_map_projection&quot; rel=&quot;nofollow noreferrer&quot;&gt;conformal&lt;/a&gt;  projection, meaning that the distance distortion values for the two dimensions are the same. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;More intuitive formulas calculate x and Y directly. For the spherical case, in the equatorial aspect:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$x=R*a_{map}*(\lambda-\lambda_0)$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$y=R*a_{map}*ln \left[ tan \left(\frac{\pi}{4} +\frac{\phi}{2}\right)\right]$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ellipsoidal formula is more complicated: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$y=a*a_{map}* ln \left[ tan \left(\frac{\pi}{4} +\frac{\phi}{2}\right) * \left(\frac{1-e* sin\phi}{1+e*sin \phi}\right)^\frac{e}{2} \right]$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(It's one of the &lt;em&gt;simplest&lt;/em&gt; ellipsoidal projection formulas, however!)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These formulas appear in &lt;a href=&quot;https://en.wikipedia.org/wiki/Mercator_projection&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Wikipedia article on the Mercator projection&lt;/a&gt; and are the ones you should pay attention to. &lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2020-05-12T18:36:13.233" LastActivityDate="2020-05-12T18:36:13.233" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18308" PostTypeId="2" ParentId="18046" CreationDate="2019-10-28T03:00:33.447" Score="1" Body="&lt;p&gt;First we should be clear on what is meant by &quot;global temperature&quot;. Averaged global surface air temperatures have become the most commonly used metric for the state of our global climate and get called &quot;global temperature&quot; but it is not an absolute measure, is not a direct measure of global climate change and it is not the only measurement that could be used. It does have the advantage of drawing on temperature records going back to before 1900. Surface air temperatures are only a good indicator of climate change when averaged over periods long enough that short term and recurring variability does not distort any calculation of trend. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This graph shows an ongoing pattern of temperatures going up and down a lot - whilst still showing a longer term trend of temperature rise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Z1UEQ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Z1UEQ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Average surface air temperatures vary widely from year to year - and yes, they have gone down 2 years running. Before that they went up for 5 years in a row. However this does not mean that there was global warming for 5 years and global cooling for 2 years; a clear underlying trend of warming (red line is smoothed 5 year running average) is there, and if anything it is shows faster warming, not slower.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looking at a different measurement - This is global ocean heat content down to 2,000m depth - it shows year to year variation but much less. It does not show 5 years of Ocean heat content going up followed by 2 years of going down or even align closely with the variations in surface air temperatures but the same underlying trend of warming as in surface air temperatures is there - &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EHvnY.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EHvnY.png&quot; alt=&quot;OHC2000m&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="18145" LastEditDate="2019-10-28T07:14:37.203" LastActivityDate="2019-10-28T07:14:37.203" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18309" PostTypeId="2" ParentId="18149" CreationDate="2019-10-28T07:34:40.360" Score="4" Body="&lt;p&gt;The question contains a false assumption that climate science fails to consider the cooling effects of aerosol particles, including from smoke, that are the principle forcing expected for nuclear winter scenarios. Climate science does attempt to quantify every significant effect, both warming and cooling - not only the warming effect from increased greenhouse gases - &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Z9ErY.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Z9ErY.jpg&quot; alt=&quot;Radiative forcings&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whilst not as recent as I would like, the graphic shows the principal climate forcings that climate science has identified and includes the cooling affects of aerosols.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Aerosols from burning forests are short-lived, and the &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; from burning vegetation should be drawn back down by regrowth, whether forest regrowth or grassland. The most significant, enduring climate consequence of Amazon forest being cleared and burned is not the aerosols or the &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; from the fires, it is from land clearing turning a large existing Carbon Sink into a carbon source. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Turning the Amazon to savannah would release 200 billion metric tons of &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;. The cooling effect of the aerosols from burning will not persist long, but the raised &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; levels from the loss of a large Carbon Sink will.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="2470" LastEditDate="2020-01-05T19:07:05.960" LastActivityDate="2020-01-05T19:07:05.960" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18310" PostTypeId="1" CreationDate="2019-10-28T09:35:05.947" Score="1" ViewCount="61" Body="&lt;p&gt;It is close to the deadline for conducting research on a research vessel for the Irish Sea (one month left). I'm currently a student and would like some descriptive observational data/variables needed to account for when recording measurements from CTD (conductivity, Temperature, Depth) and ADCP (Acoustic Doppler Current Profile) instruments. For both CTD and ADCP, what do I need from these devices to create a general log sheet suitable for all students (my crew) to record during the trip.     &lt;/p&gt;&#xA;" OwnerUserId="18112" LastActivityDate="2019-11-26T12:23:04.377" Title="Creating a general log sheet for CTD and ADCP for fieldwork" Tags="|oceanography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18311" PostTypeId="1" CreationDate="2019-10-28T14:14:26.190" Score="1" ViewCount="92" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_sensitivity#Estimating_climate_sensitivity&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Climate_sensitivity#Estimating_climate_sensitivity&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;This indicates that current &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; levels have a temperature equilibrium of 2.2 &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{^oC}$&lt;/span&gt; disagreeing with statements that we are still below 1.5 &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{^o}$&lt;/span&gt;C. What did I do wrong?&lt;/strong&gt;&lt;br&gt;&#xA;280 PPM * 2 = 560 ppm&lt;br&gt;&#xA;410 PPM / 560 ppm = 73%&lt;br&gt;&#xA;73% * 3 &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{^o}$&lt;/span&gt;C = 2.2 &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{^o}$&lt;/span&gt;C&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://skepticalscience.com/climate-sensitivity-advanced.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://skepticalscience.com/climate-sensitivity-advanced.htm&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17970" LastEditorUserId="2470" LastEditDate="2020-01-05T19:18:33.287" LastActivityDate="2020-01-06T12:14:41.597" Title="How do we apply CO2 sensitivity (3C ± 1.5C for every doubling) to current CO2 levels" Tags="|climate-change|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18313" PostTypeId="2" ParentId="18298" CreationDate="2019-10-29T02:49:23.760" Score="3" Body="&lt;h2&gt;There are a few ways&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Basically the best way is to see how many experts in the field are convinced, as great as it would be to assess the evidence individually, one person can't be an expert in everything and unless you and your audience are a climate scientists most papers are going to be beyond a lay assessment. So the best thing you can do for the lay public is look to the experts, people who have spent decades researching the subject and have the best ability to assess the data, and see what their assessment is. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;NASA has a &lt;a href=&quot;https://climate.nasa.gov/faq/17/do-scientists-agree-on-climate-change/&quot; rel=&quot;nofollow noreferrer&quot;&gt;wonderful site&lt;/a&gt; dedicated to collecting assessments. They fall into three rough categories. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Meta analysis&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A meta &lt;a href=&quot;https://iopscience.iop.org/article/10.1088/1748-9326/8/2/024024&quot; rel=&quot;nofollow noreferrer&quot;&gt;analysis&lt;/a&gt; of published works shows the number of scientific papers rejecting anthropomorphic climate change is vanishingly small (0.7%) and shrinking. those uncertain was even smaller (0.3%)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Professional survey&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;the same &lt;a href=&quot;https://iopscience.iop.org/article/10.1088/1748-9326/8/2/024024&quot; rel=&quot;nofollow noreferrer&quot;&gt;analysis&lt;/a&gt; also surveyed 29,000 published climatologists and showed a 97% support for anthropomorphic climate change and the rest being largely no-position. this is even skewed by expertise, when accounting for the number of &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2901439/&quot; rel=&quot;nofollow noreferrer&quot;&gt;published&lt;/a&gt; papers (a rough way of measuring expertise) it shows even stronger support among more published authors with most of the opposition being from authors that only publish a small number of papers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Public statements by relevant scientific societies.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.ametsoc.org/index.cfm/ams/about-ams/ams-statements/archive-statements-of-the-ams/climate-change1/&quot; rel=&quot;nofollow noreferrer&quot;&gt;American Meteorological Society&lt;/a&gt; and &lt;a href=&quot;https://www.geosociety.org/gsa/positions/position10.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geological Society of America&lt;/a&gt; as well &lt;a href=&quot;https://climate.nasa.gov/scientific-consensus/&quot; rel=&quot;nofollow noreferrer&quot;&gt;as many others&lt;/a&gt; have made public statements in favor of anthropomorphic climate change. And of course you have the &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/02/ipcc_wg3_ar5_summary-for-policymakers.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;statements&lt;/a&gt; by the Intergovernmental Panel on Climate Change.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="18166" LastEditDate="2019-10-30T10:38:14.277" LastActivityDate="2019-10-30T10:38:14.277" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="18314" PostTypeId="2" ParentId="18311" CreationDate="2019-10-29T05:37:00.847" Score="2" Body="&lt;p&gt;You have done multiple things wrong here. One is that you have used a linear interpolation when you should have used a logarithmic interpolation. But that's a different question, one that &lt;a href=&quot;https://earthscience.stackexchange.com/questions/18266&quot;&gt;you have already asked&lt;/a&gt;. I'll address that there. That said, a logarithmic interpolation would indicate that the warming due to a 73% increase would be 2.37 °C rather than 2.2 °C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But that math is incorrect. We have not seen a 73% increase in &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; levels over preindustrial times. We have seen a 46.4% increase. The second thing you have done wrong is to incorrectly apply a linear interpolation. The correct value, assuming a linear interpolation is correct, is &lt;span class=&quot;math-container&quot;&gt;$\left(\frac{410-280}{560-280}\right)3^{\circ}$&lt;/span&gt;, or 1.39 °C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We have seen more than a 1.39 °C increase from preindustrial times due to the 46.4% increase in &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; levels over preindustrial times. The correct math is a logarithmic interpolation: &lt;span class=&quot;math-container&quot;&gt;$\log_2\left(1+\frac{410-280}{560-280}\right)3^{\circ}$&lt;/span&gt;, or 1.65 °C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We have not quite seen a 1.65 °C increase. So what's going on? Another thing you have done wrong is to implicitly assume that the current climate represents the steady-state response to the current &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; level. It does not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Climate instead changes rather slowly. Suppose we stopped adding ever more &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; to the atmosphere but instead maintained &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; at the current level of 410 ppm. Temperatures will continue to rise for quite some time because the climate has not yet reached its steady-state response to the rather sudden rise from 280 ppm &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; to the current level of 410 ppm.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2020-01-06T12:14:41.597" LastActivityDate="2020-01-06T12:14:41.597" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18315" PostTypeId="2" ParentId="18266" CreationDate="2019-10-29T05:56:16.107" Score="1" Body="&lt;p&gt;To get a rough estimate you should be using a logarithmic interpolation rather than a linear interpolation. The response to added &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; would be linear if the atmosphere had barely any &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; in it. Even 280 ppm does not qualify as &quot;very little&quot;. &quot;Very little&quot; would mean a handful of parts per million, at most.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The issue is that the atmosphere is rather opaque at those frequencies where &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; absorbs and emits thermal infrared radiation. Instead of a linear response, the response in terms of radiative forcing is roughly logarithmic. This is why climatologists talk about the effect of a doubling the &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; levels. The radiative forcing of an increase from 140 ppm &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; to 280 ppm is more or less the same as the response to an increase from 280 ppm to 560 ppm, or to an increase from 560 ppm to 1120 ppm.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2019-10-29T05:56:16.107" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="18316" PostTypeId="2" ParentId="18264" CreationDate="2019-10-29T09:02:12.493" Score="1" Body="&lt;p&gt;Hyperspectral analysis is being used in mining and exploration extensively as a cheaper and quicker alternative to the likes of x-ray fluorescence, x-ray diffraction and others. Hyperspectral is even being used on an active mining faces with scanners installed on excavators and processed image being fed to a computer display that operator can use to direct digging of ores.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, as to the crux of your question - no, or at least very difficult. The problem with hyperspectral for ranged resource detection is that it primarily uses visual and near-infrared parts of spectrum. These wavelengths are very easily absorbed/scattered by everything and, therefore, they lack any penetration. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In most cases Earth's surface on satellite imagery will be covered by vegetation and various recent sedimentary formations which will make it nigh impossible to 'see' the bedrock potentially containing ore-bearing rock types and mineralogies. &lt;/p&gt;&#xA;" OwnerUserId="18158" LastActivityDate="2019-10-29T09:02:12.493" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18317" PostTypeId="2" ParentId="18259" CreationDate="2019-10-29T09:26:29.833" Score="0" Body="&lt;p&gt;My thinking is that average scale of volcanic eruptions and resultant emissions should be the most stable on the scale of hundreds and thousands of years.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Yearly and decade scale: Major variations where a single large eruption will result in a year being an outlier&lt;/li&gt;&#xA;&lt;li&gt;100-1000 year scale: Generally quite consistent. No major changes in areas of volcanic activity and random outliers won't have a drastic effect on an average activity&lt;/li&gt;&#xA;&lt;li&gt;10,000-100,000 year scale: This is the time scale close to the average life time of a volcano within a subduction zone due to movement of plates and source of magma moving away from the current active area. As a result on this time scale we should expect some older volcanoes to become dormant and new ones to pop up but there won't be much consistency&lt;/li&gt;&#xA;&lt;li&gt;Scale of millions of years: Major changes in geometry and activity of subduction zones, potentially new areas of rifting opening up, so overall not very stable&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="18158" LastActivityDate="2019-10-29T09:26:29.833" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18318" PostTypeId="2" ParentId="18247" CreationDate="2019-10-29T09:43:37.297" Score="0" Body="&lt;p&gt;Normally, during an earthquake most deaths occur when people get buried under collapsing buildings. Assuming as in your question, a person was away from anything that could fall on them and didn't fall into a ravine and didn't get swallowed in a newly formed quicksand, it should be possible to survive a mag 9 event.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The biggest danger in this situation will be a result of rapid acceleration, referred to as &lt;a href=&quot;https://en.wikipedia.org/wiki/Peak_ground_acceleration&quot; rel=&quot;nofollow noreferrer&quot;&gt;Peak Ground Acceleration&lt;/a&gt;. In recent years the highest recorded ground acceleration during an earthquake was recorded during 2016 event on the South Island of New Zealand with peak values of 3g (30 &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{m/s^2}$&lt;/span&gt;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A healthy person should have no issues surviving acceleration of this magnitude, especially if lying on the ground. This is due to the fact that people are more resilient to acceleration directed from front to back as opposed to from feet-to-head (or other way around). Bruises and (not very likely) broken ribs would be the biggest issues in such a case.&lt;/p&gt;&#xA;" OwnerUserId="18158" LastEditorUserId="2470" LastEditDate="2020-01-05T19:25:34.670" LastActivityDate="2020-01-05T19:25:34.670" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18319" PostTypeId="2" ParentId="18259" CreationDate="2019-10-29T10:22:50.937" Score="2" Body="&lt;p&gt;If you have access, I would recommend you to read &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/B9780123859389000146&quot; rel=&quot;nofollow noreferrer&quot;&gt;this short chapter&lt;/a&gt; of the Encyclopedia of Volcanoes. In summary:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;At ocean ridges&lt;/strong&gt;, studies show a steady rate of oceanic crust production during the Cenozoic. There have been fluctuations before, maybe due to the breakup of Pangea or other major tectonic events. The present volcanic production rate is ~20 km&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt; per year.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;At volcanic arcs&lt;/strong&gt;, it is harder to constrain because of the poor preservation of volcanic material. Tephra layers found in deep sea drilling cores show some peaks in explosive activity &quot;in the Quaternary (0-5 Ma), the middle Miocene (c. 13-17 Ma), and potentially the Eocene (c. 37-42 Ma)&quot;. This is not well explained. There is also a shorter term variability due to deglaciation episodes: mass unloading depressurize magmatic systems. A conservative estimate of the modern output is 0.5 km&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt; per year.&lt;/li&gt;&#xA;&lt;li&gt;Finally, &lt;strong&gt;Large Igneous Provinces&lt;/strong&gt; (LIPs) are very episodic (long-term average of one LIP every 10-20 Ma) but they emit a large volume (generally &gt; 1 million km&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt;) in a relatively short period of time (a few million years). LIP emplacement coincide with major mass extinction events.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2020-01-06T13:35:14.047" LastActivityDate="2020-01-06T13:35:14.047" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18320" PostTypeId="1" AcceptedAnswerId="18323" CreationDate="2019-10-29T12:30:41.623" Score="2" ViewCount="101" Body="&lt;p&gt;The LAFD reported that the Getty fire near Los Angeles is &quot;5% contained&quot;. What is meant by &quot;containment&quot; and what does 5% containment mean in this context? I've tried googling &quot;wildfire containment&quot; but all I'm getting is news articles about a different currently ongoing wildfire.&lt;/p&gt;&#xA;" OwnerUserId="1013" LastActivityDate="2019-10-29T15:53:21.707" Title="What does the containment percentage mean when a fire department is reporting on a wildfire?" Tags="|wildfire|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18321" PostTypeId="1" CreationDate="2019-10-29T13:05:41.827" Score="3" ViewCount="58" Body="&lt;p&gt;I read in various places that CAPE is the area between temperature and the saturated adiabat through LCL from LFC to EL and approximated by &lt;span class=&quot;math-container&quot;&gt;$\bigl(\sum_{i=LFC}^{EL} {T_{ap}-T_e\over T_e} \overrightarrow g\bigr)\Delta z$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have plotted the CAPE for a sounding and want to instead calculate the area from the resulting CAPE polygon. When I use the shoelace formula to do so I however always come to a number which seems too far off from the approximation to be correct. It is within the same order of magnitude but just doesn't seem right.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the correct way to interpret the CAPE as being this 'area' ? Can I calculate it as I did or can it only be approximated as per the formula ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Update: changing the base from the surface reading to 1000mb brings the calculation closer to estimates however i hope someone can still comment on the accuracy of my interpretation on the meaning of 'area' and whether it really is the surface area of the CAPE polygon&lt;/p&gt;&#xA;" OwnerUserId="11347" LastEditorUserId="11347" LastEditDate="2019-10-31T07:50:28.447" LastActivityDate="2019-10-31T07:50:28.447" Title="CAPE Calculation" Tags="|radiosounding|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18322" PostTypeId="2" ParentId="18320" CreationDate="2019-10-29T14:26:03.540" Score="0" Body="&lt;p&gt;One hundred percent contained would mean that the fire had been completely stopped from spreading further, but not necessarily been put out. By five percent contained, which is only an approximate figure, the commentator meant that the fire was still spreading but, thanks to the firefighters efforts, to a slightly lesser extent than it had been earlier.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-10-29T14:35:54.940" LastActivityDate="2019-10-29T14:35:54.940" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18323" PostTypeId="2" ParentId="18320" CreationDate="2019-10-29T15:53:21.707" Score="6" Body="&lt;p&gt;One hundred percent contained means that there are suitable fire guards around 100 percent of the circumference of the fire.  The fire guards can be either created such as a hand or machine dug firebreak, a retardant break (often placed by air tanker), or a natural feature such as a river or bare rock cliff.  Containing a fire is just a step in controlling the fire, after containment, there are other phases that may or may not be completed such as back burning off the break lines, extinguishment, and finally monitoring.  Even once a fire is 100% contained it is not that uncommon for the fire to &quot;jump the guard&quot; if the weather conditions change.  The percentage of containment also gives an indication as to how much access the fire crews have to the fire, a well-contained fire implies that the fire crew has access to be able to fight the fire, this is the major secondary goal for the dug firebreaks.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;5 percent contained implies that some form of command has been established and the fire crew(s) are just starting to contain the fire.  I wouldn't read much more into the statement.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2019-10-29T15:53:21.707" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18324" PostTypeId="1" CreationDate="2019-10-29T15:58:32.473" Score="1" ViewCount="55" Body="&lt;p&gt;I just moved to Wisconsin, so my family is throwing snow statistics at me. But it seems to me that the most meaningful average US snowfall statistic isn't available (or easy to find).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The average snowfall in the US is 28 inches.  But that includes places that never or rarely get snow.  A better stat would limit to places that get some modicum of snow annually. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, what is the average snowfall for places (perhaps cities) that get at least an inch of snow annually?&lt;/p&gt;&#xA;" OwnerUserId="18161" LastActivityDate="2019-10-30T00:31:41.383" Title="Average Snowfall for Snowy Places?" Tags="|meteorology|snow|statistics|severe-weather|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18325" PostTypeId="1" AcceptedAnswerId="18330" CreationDate="2019-10-29T21:35:11.467" Score="6" ViewCount="1097" Body="&lt;p&gt;I found &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9685/do-divergent-tectonic-plates-destroy-mountains?newreg=a47a12f35faf46aab80e38009b2baba1&quot;&gt;this&lt;/a&gt; question, which is similar to what I'm wondering, but my question is slightly different:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What happens if a new divergent boundary forms in a way that bisects a mountain range, especially one formed by converging plates -- and is that even possible? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Purely for the sake of example, if a divergent rift somehow formed on the North American plate, dividing the Appalachians &lt;strong&gt;[ETA: apparently I circled a valley, please pretend I'm not a geography-illiterate dork and that it's actually some old mountains.]&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/q8LNc.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/q8LNc.jpg&quot; alt=&quot;Satellite image of the North American eastern coast + Appalachian mountains&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would happen to the circled area? Anything? Would the mountain range be recognizable after an ocean formed between them? Considering the timescale involved, perhaps an older range would be unrecognizably eroded? I've tried to find examples in the real world, but my Google-fu fails me. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Somewhere I picked up the idea that the Appalachian and Welsh coal seams were once connected or formed together (I think it may have been from an offhand comment in a movie about Welsh miners, so a] maybe I understood wrong and b] who knows how accurate it was), so I initially wondered if that might be an example of what I'm curious about. Unfortunately, some light research seems to indicate that's not the case (if I'm understanding &lt;a href=&quot;https://en.wikipedia.org/wiki/Coal_industry_in_Wales&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Pittsburgh_coal_seam&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt; correctly, the connection ends at &quot;both formed, at least partially, during the Carboniferous.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm most interested in what the effects (if any) would be on older mountain ranges such as the Urals or Appalachians, but if anyone knows what kind of effects it might have on younger, taller ranges, I'd love to hear about it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If anyone has sources I could look into for a deeper understanding, I'd love to have those as well! My lack of knowledge is distressing me to no end.&lt;/p&gt;&#xA;" OwnerUserId="18162" LastEditorUserId="18162" LastEditDate="2019-10-29T21:45:47.927" LastActivityDate="2019-10-30T01:22:52.697" Title="What is the impact of divergent tectonic plates on old mountain ranges?" Tags="|plate-tectonics|mountains|tectonics|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18326" PostTypeId="2" ParentId="18149" CreationDate="2019-10-29T21:51:32.353" Score="1" Body="&lt;p&gt;While the main emissions from these fires are &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; and CO, the more important difference is what happens to the poorly combusted carbon products that are aggregated into larger particles.  The climate community tends to refer to these as black carbon (BC), although that’s &lt;a href=&quot;https://www.atmos-chem-phys.net/6/3131/2006/&quot; rel=&quot;nofollow noreferrer&quot;&gt;an oversimplification&lt;/a&gt;.  These BC particles are strong absorbers of solar radiation, causing local atmospheric heating, but they also have a very short lifetime in the troposphere (~5 days; &lt;a href=&quot;https://doi.org/10.5194/acp-15-8201-2015&quot; rel=&quot;nofollow noreferrer&quot;&gt;Baker et al, 2015&lt;/a&gt;), so the amount of BC in the atmosphere at any one time is relatively small (~0.1 Tg).  This has an overall warming effect on the troposphere, which is why it’s included in calculations of historical and future greenhouse warming, but it’s not as large as that of a long lived and abundant species like &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An important thing to note is that there are large scale differences between current, normal smoke emissions and those from a nuclear incident.  Current BC emissions from all sorts of surface burning processes are about 7.2 Tg / yr (~0.02 Tg / day; &lt;a href=&quot;https://www.atmos-chem-phys.net/17/8681/2017/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kilmont et al, 2017&lt;/a&gt;).  A big number compared with that ~0.1 Tg atmospheric burden but, as I say, the removal processes are fast.  These emissions are spread over most of the global land area (although they’re greatest in Africa, India and China), so the emissions per unit area are also relatively low.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;In a single nuclear incident the BC emissions would be much greater, would occur in a small area and would be injected throughout the troposphere&lt;/strong&gt;.  For example, &lt;a href=&quot;http://www.atmos-chem-phys.net/7/2003/2007/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Robock et al (2007)&lt;/a&gt;, the same people you link to in your question, ran this simulation:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In our standard calculation, we inject 5 Tg of black carbon on 15 May into one column of grid boxes at 30 N, 70 E. We place the black carbon in the model layers that correspond to the upper troposphere (300–150 mb).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is a huge perturbation - about 50 times the current atmospheric total and about 250 times the current daily flux.  They found that the BC entered the stratosphere, where removal processes are much slower than in the troposphere, such that,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;E-folding times are 6 y, compared with 1 y for volcanic eruptions and 1 week for tropospheric aerosols.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The BC then absorbs solar radiation and heats the stratosphere, reducing the amount of solar radiation reaching the surface and cooling surface air temperature by more than 1 degree Celsius for about 5 years.  Note that the associated &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; emissions would warm the troposphere, but over a slower time scale and these studies tend to concentrate on the immediate BC cooling effect of a nuclear incident.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an additional bit of contrast, that study also found that,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;When we placed the aerosols in the lower troposphere (907–765 mb), about half of the aerosols were removed within 15 days&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This indicates how important it is for the BC emissions to reach the stratosphere in order get a prolonged surface cooling.&lt;/p&gt;&#xA;" OwnerUserId="106" LastEditorUserId="2470" LastEditDate="2020-01-05T19:10:05.443" LastActivityDate="2020-01-05T19:10:05.443" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18327" PostTypeId="2" ParentId="18325" CreationDate="2019-10-29T22:15:36.770" Score="4" Body="&lt;p&gt;Divergent boundaries are going to form where the crust is weak and thin, a divergent boundary siis very unlikely to form in an existing mountain range.  Imagine trying to pull apart a lumpy cookie, is it going to break through the thick lumps or the thin areas. That's not saying a rift could not cut across a mountain range but it will be very unlikely,  it is woll do just that, cut across it. If it does you are left with two mountain ranges, mountains are constantly falling back to neutral height since the moment they are formed, tearing them apart just speeds that up in a very localized region. What is more likely is a mountain range getting pushed over an existing spreading center, which has happened in the western US. and the result is the entire continent and mountain range slowing being stretched and thinned in a rough irregular manner at the same time it is getting pushed up higher and higher as rising magma essentially underplates it. This is why the western US contains so much highlands. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://geologycafe.com/geologic_history/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;This should be helpful.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now of course &quot;mountain&quot; are a relative measure, there are a lot of types of mountains, so a rift valley can actually be bordered by mountains created by the rifting itself, areas that have simply not thinned next to areas that are thinning are also called highlands or mountains depending on how extensive they are. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For your more specific question, the appalachians are part of the central pangea range, which included the anti-atlas range of africa and the scottish highlands, so no not the same. however the range included multiple mountain building events so they may indeed be connected by events. The welsh coalfields were swamps at the time likely fed from from those mountains. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2019-10-30T01:22:52.697" LastActivityDate="2019-10-30T01:22:52.697" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18329" PostTypeId="2" ParentId="18325" CreationDate="2019-10-29T23:40:11.203" Score="2" Body="&lt;p&gt;If you want to know about what happens with diverging plates, the best example to look at is the East African Rift Valley. An existing plate is forced to split apart by a mantle plume or plumes, and this is likely to be accompanied by volcanism as is the case in East Africa. It is theoretically possible for the rift to cut through mountains, and this seems to have happened near the Afar region of Ethiopia, but a developing rift would tend to avoid very large mountains and seek more easily fractured terrain. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The East African Rift is exceptional in being by far the largest in the world. Mid Ocean Ridges share some features in common with the diverging plates of rift valleys. If you think of Iceland as being a mountain, a mid ocean ridge and its associated rift runs straight through it and is the cause of Iceland's volcanism. Britain and North America were once connected, but I don't think the Appalachian and Welsh coal seams were.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-10-29T23:40:11.203" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18330" PostTypeId="2" ParentId="18325" CreationDate="2019-10-30T00:16:44.100" Score="5" Body="&lt;p&gt;The example of the East African Rift was given in a different answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Splitting of mountain ranges in two becomes even more apparent as you go up north from there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Red Sea between Egypt and Saudi Arabia is a young new spreading ocean, that cuts through Precambrian mountains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Zk1mR.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Zk1mR.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Further north from there, the Dead Sea is a combined transform–rift zone where you have the same thing. Precambrian mountain ranges overlain by Cretaceous sediments (folded into mountain ranges) are being torn apart to form the Dead Sea depression.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/knLH8.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/knLH8.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-10-30T00:16:44.100" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18332" PostTypeId="2" ParentId="18324" CreationDate="2019-10-30T00:31:41.383" Score="1" Body="&lt;p&gt;Here are some cities and locations&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Average Annual Snowfall for the Following Cities and Locations (in inches)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Asheville, North Carolina: 9.9”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Waynesville, North Carolina: 14.1”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Milwaukee, Wisconsin: 46.9”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Madison, Wisconsin: 50.9”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Syracuse, New York: 123.8”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Buffalo, New York: 94.7”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Smugglers Notch, Vermont: 59.8”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Burlington, Vermont: 59.8”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mount Washington, New Hampshire: 281.2”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Morristown, New Jersey: 14.1”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;New York City, New York: 25.8”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Montpellier, Vermont: 94.2”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ogden, Utah: 22.1”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Salt Lake City, Utah: 56.2”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Barrow, Alaska: 37.7”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seattle, Washington: 6.8”&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alta, Utah: 549”&lt;/p&gt;&#xA;" OwnerUserId="17923" LastActivityDate="2019-10-30T00:31:41.383" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18333" PostTypeId="1" AcceptedAnswerId="18336" CreationDate="2019-10-30T02:47:48.040" Score="6" ViewCount="165" Body="&lt;p&gt;The BBC News item &lt;a href=&quot;https://www.bbc.com/news/uk-scotland-north-east-orkney-shetland-50222151&quot; rel=&quot;noreferrer&quot;&gt;Double reflected rainbow photographed in Orkney&lt;/a&gt; shows an unusual kind of double rainbow.&lt;/p&gt;&#xA;&lt;p&gt;According to the article:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The image was captured by Martin Gray at Gyran on Tuesday morning, who described the sight as &amp;quot;amazing&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;He said: &amp;quot;I'm used to seeing double rainbows, but this was a really weird-looking thing.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;[...]&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;I quickly snapped a few photos. It was extremely bright, and odd looking - all odd angles. &amp;quot;But I didn't even notice the faint fourth arc until I carefully looked at my photographs.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;BBC weatherman Simon King said it was an &amp;quot;impressive&amp;quot; photograph. &amp;quot;It's a really impressive double reflected rainbow,&amp;quot; he said. He said the photographer had a loch behind him at the time.&lt;/p&gt;&#xA;&lt;p&gt;As a result, sunlight had bounced off the loch before reaching the water droplets from a rain shower in front of him. The sunlight was then bent and reflected inside the droplet back to the photographer.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; I've annotated the image and numbered each of the arcs. Is it possible to sort out what's going on and which phenomenon are responsible for each of them?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BkbPy.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BkbPy.jpg&quot; alt=&quot;double reflected rainbow (BBC, Martin Gray at Gyran)&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Credit: Martin Gray &amp;amp; BBC; Gyran, Orkney Islands, Scotland&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-10-30T13:40:45.807" Title="Help understanding this image of an unusual double reflected rainbow" Tags="|atmospheric-optics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18334" PostTypeId="2" ParentId="18149" CreationDate="2019-10-30T03:25:51.257" Score="2" Body="&lt;p&gt;Dedito's answer is valid, but I wanted to offer a laymen's version.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A nuclear winter scenario blocks the sun's rays from &quot;smoke&quot; (e.g. particulate matter,  not transparent gases such as CO and &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;).  This causes a net global cooling effect, due to the large volume of particulate that is trapped in the stratosphere and reflecting sunlight back to space.   The driving principles involved in this process are indeed included in climate models and global warming predictions.  However, the net effect for &quot;business as usual&quot; scenario is a net warming.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nuclear explosions create so much heat, that they inject particulate matter into the stratosphere.  Large volcanic &#xA; eruptions also inject particulate into the stratosphere, often discussed in climate model analyses.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Typical particulate matter emissions (e.g. from cars, industry, etc.) stay in the troposphere where they can deposit on the surface, chemically react (with water), or disperse.  In contrast, the stratosphere only has dispersion as a mechanism for removing particulate. Furthermore, air in the stratosphere does not easily mix downward to the troposphere, due to the tropopause, and it is void of moisture. Thus, large heat sources (e.g. nuclear bombs, volcanoes, and megafires) can push particulate into the stratosphere where it stays trapped for years.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="2470" LastEditDate="2020-01-05T19:07:36.547" LastActivityDate="2020-01-05T19:07:36.547" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18336" PostTypeId="2" ParentId="18333" CreationDate="2019-10-30T13:20:48.560" Score="6" Body="&lt;p&gt;What you are seeing are a primary rainbow (rainbow #2 in the linked image), its secondary rainbow (#4), a &lt;a href=&quot;https://www.atoptics.co.uk/rainbows/reflect.htm&quot; rel=&quot;noreferrer&quot;&gt;reflection rainbow&lt;/a&gt; (#1), and its secondary (#3).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note well: The linked article called these reflected rainbows, but that is incorrect. A &lt;a href=&quot;https://www.atoptics.co.uk/rainbows/rflctd.htm&quot; rel=&quot;noreferrer&quot;&gt;reflected rainbow&lt;/a&gt; is yet another atmospheric optical phenomenon that occurs when one sees what appears to be the reflection of a rainbow on water in front of the viewer. The water was behind the photographer in the linked image, and the extra two rainbows were in the sky rather than in the water. (There is no water in the linked image.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reflection of the Sun off of the water behind the viewer result in a reflection rainbow in front of the viewer. The center of a primary rainbow is the antisolar point from the perspective of the viewer of the rainbow, which is below the ground. The center of a reflection rainbow is the anthelic point of the reflection of the Sun, which is above the ground. Thus rainbow #1, the primary rainbow from the Sun itself, is lower than rainbow #2, the primary rainbow from the Sun's reflection off the loch behind the photographer. The two rainbows intersect at the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rainbows can have secondaries, and so can reflection rainbows. These are bows number 4 and 3. Note that the sky and land are darker between the primary and secondary, brighter outside the secondary, and much brighter inside the primary. The lighting outside the secondary is the natural lighting level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One way of looking at rainbows is that they transfer some of the light that would normally fall between the primary and secondary to inside the primary, and that this transference changes a bit with frequency.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="6031" LastEditDate="2019-10-30T13:40:45.807" LastActivityDate="2019-10-30T13:40:45.807" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18338" PostTypeId="1" AcceptedAnswerId="18339" CreationDate="2019-10-30T16:49:23.573" Score="1" ViewCount="23" Body="&lt;p&gt;For my thesis on modelling an extreme rainfall event with a 2D surface runoff model I'm supposed to consider the effect of soil infiltration on the runoff: In my work description it says I'm supposed to &quot;choose an appropriate approach to model soil infiltration because 'blanket approaches' (if its the correct english translation) have uncertainties&quot;. As an 'appropriate approach' I got recommended to use a software which computes a runoff-coefficient. But what are the 'blanket approaches'? I probably need to use one or more of those 'blanket approaches' and compare them with the results from the software. Any ideas what is meant?     &lt;/p&gt;&#xA;" OwnerUserId="18169" LastActivityDate="2019-10-30T21:18:33.473" Title="Modelling extreme rainfall events: 'blanket approches' when considering soil infiltration" Tags="|hydrology|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18339" PostTypeId="2" ParentId="18338" CreationDate="2019-10-30T21:18:33.473" Score="1" Body="&lt;p&gt;I would be surprised if the rainfall-runoff relationship would show a linear relationship for extreme events. I would consider that to be a blanket approach, if you mean using a constant coefficient. So consider using a higher order relationship.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another thing to consider is whether the rainfall runoff relationship depends on the soil moisture. Maybe check out how other models like SWAT deal with this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To be honest, I think that the amount of soil infiltration will be insignificant for extreme rain events because it occurs too slowly compared to the rainfall rate and other uncertainties.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2019-10-30T21:18:33.473" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18340" PostTypeId="1" CreationDate="2019-10-30T22:22:45.747" Score="1" ViewCount="53" Body="&lt;p&gt;Why is it that Spring in the Great Smoky Mountains National Park is the peak season for forest fires both man made and lightning caused when it rains so much in the spring and it is so wet there in the Spring so how can forest fires possibly form and even be the peak season for fires there?&lt;/p&gt;&#xA;" OwnerUserId="17923" LastActivityDate="2019-10-31T18:52:19.103" Title="Great Smoky Mountains National Park" Tags="|forest|wildfire|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18341" PostTypeId="1" AcceptedAnswerId="18343" CreationDate="2019-10-31T01:10:38.463" Score="2" ViewCount="7493" Body="&lt;p&gt;I have precipitation data in mm/h but to use them for my model I need them in m³/s. Is there a formula to convert them? &lt;/p&gt;&#xA;" OwnerUserId="18169" LastEditorUserId="18081" LastEditDate="2019-10-31T16:34:01.270" LastActivityDate="2020-01-05T19:04:50.153" Title="formula to convert precipitation in mm/h to runoff in m³/s" Tags="|meteorology|hydrology|mathematics|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18342" PostTypeId="2" ParentId="18305" CreationDate="2019-10-31T05:09:17.273" Score="1" Body="&lt;p&gt;Out here in the Western U.S. the &lt;a href=&quot;https://wrcc.dri.edu&quot; rel=&quot;nofollow noreferrer&quot;&gt;Western Regional Climate Center&lt;/a&gt; offers such historical data for download.  If I recall, their downloads are in .csv format, not .json. However, converting data formats is relatively straightforward for GIS software, such as QGIS.&lt;/p&gt;&#xA;" OwnerUserId="4626" LastActivityDate="2019-10-31T05:09:17.273" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18343" PostTypeId="2" ParentId="18341" CreationDate="2019-10-31T09:30:45.760" Score="1" Body="&lt;p&gt;When we say there was 1 mm (or 0.001 m) of rain, it is assumed that it is on a 1 square meter area, so it is equivalent to a volume of water of 0.001 &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{m^3}$&lt;/span&gt; (or one liter). So first you have to divide your data by 1000.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then you have time, which is easy: there are 3600 seconds in one hour. So to convert L/h in m&lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{^3}$&lt;/span&gt;/s, you have to divide your data by 3,600,000:&#xA;&lt;strong&gt;1 L/h = 2.7778 x 10&lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{^{-7}}$&lt;/span&gt; m&lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{^3}$&lt;/span&gt;/s.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can ask this sort of things in &lt;a href=&quot;https://www.wolframalpha.com/input/?i=1%20l%2Fh%20in%20m3%2Fs&quot; rel=&quot;nofollow noreferrer&quot;&gt;WolframAlpha&lt;/a&gt;; the trick here is to &quot;convert&quot; mm/h, assumed by the engine to be a speed, in L/h, the volume flow rate hidden by the mm/h unit.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="2470" LastEditDate="2020-01-05T19:04:50.153" LastActivityDate="2020-01-05T19:04:50.153" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18344" PostTypeId="1" CreationDate="2019-10-31T10:55:54.070" Score="3" ViewCount="139" Body="&lt;p&gt;So I have been spending time in Moscow Russia which essentially records very similar climatic humidity to my home city of London. However in Moscow my throat is permanently dry, I need to consume more water, many people have humidifiers in their bedrooms and the government spray the roads with water to prevent citizens choking on the dry dusty air. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clearly the climate is 'drier' (or another more accurate technical adjective). What metric will show this difference between Moscow and London ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And why is the humidity metric the same ?&lt;/p&gt;&#xA;" OwnerUserId="11562" LastEditorUserId="6" LastEditDate="2020-02-01T10:21:08.400" LastActivityDate="2020-02-01T10:21:08.400" Title="What the humidity metric is hiding?" Tags="|climate|humidity|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18346" PostTypeId="2" ParentId="18341" CreationDate="2019-10-31T15:58:43.380" Score="0" Body="&lt;p&gt;You cannot make the conversion.  mm/hr describes the amount of precipitation that falls over an area but is independent of the area over which the precipitation falls.  Getting 1 mm/hour implies a light shower, whereas 20mm/hour a heavy rain.  If you describe the precipitation as m3/s you don't really know the rate at which the precipitation is falling without also knowing the area over which it is measured.  For example, if you have 1 m3/hr what does that really mean? it could mean a light dusting of snow if you are talking about 100 hectares of land, or a torrential downpour if your area was 10 meters squared of land.&#xA;Typically m3/s is used to measure flow rates for a river, creek, or channel.  You can use rate of precipitation mm/hr in conjunction with an area to determine the total volume of precipitation but overall the two rates are measuring somewhat different things.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Overall without an area you cannot convert mm/h to a volume uses in m3/s.&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastEditorDisplayName="user824" LastEditDate="2019-10-31T17:59:47.200" LastActivityDate="2019-10-31T17:59:47.200" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18348" PostTypeId="2" ParentId="18344" CreationDate="2019-10-31T17:40:09.733" Score="7" Body="&lt;p&gt;Weather services rarely state the absolute &lt;a href=&quot;https://science.howstuffworks.com/nature/climate-weather/atmospheric/question6511.htm&quot; rel=&quot;noreferrer&quot;&gt;humidity&lt;/a&gt; because it is not easy to determine. Instead, they state the relative humidity.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Absolute humidity&lt;/strong&gt; is the mass of water vapor divided by the mass of dry air in a volume of air at a given temperature. The hotter the air is, the more water it can contain. Absolute humidity is expressed as grams of moisture per cubic meter of air (&lt;span class=&quot;math-container&quot;&gt;$\mathsf{g/m^3}$&lt;/span&gt;).&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;strong&gt;Relative humidity&lt;/strong&gt; is the ratio of the current absolute humidity to the highest possible absolute humidity (which depends on the current air temperature). A reading of 100 percent relative humidity means that the air is totally saturated with water vapor and cannot hold any more, creating the possibility of rain.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A better measure of how atmospheric moisture will affect people and the environment is the &lt;a href=&quot;https://science.howstuffworks.com/nature/climate-weather/atmospheric/question6511.htm&quot; rel=&quot;noreferrer&quot;&gt;dew point&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The &lt;strong&gt;dew point&lt;/strong&gt; is, in short, the point at which dew droplets form on objects like grass – in other words, when a relative humidity of 100 percent is achieved.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;If you want a real judge of just how &lt;a href=&quot;https://www.weather.gov/arx/why_dewpoint_vs_humidity&quot; rel=&quot;noreferrer&quot;&gt;&quot;dry&quot; or &quot;humid&quot;&lt;/a&gt; it will feel outside, look at the dew point instead of the RH. The higher the dew point, the muggier it will feel.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;h2&gt;Edit 31 January 2020&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Taken from &lt;em&gt;&lt;a href=&quot;https://www.abc.net.au/news/2020-01-31/hot-humid-weather-welcome-to-the-tropics/11917070&quot; rel=&quot;noreferrer&quot;&gt;Oppressive, humid conditions for southern Australia as heatwave combines with tropical airmass&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Dew point is the indicator of the amount of moisture in the air ...&#xA;  it's the temperature that the air needs to cool to in order to form cloud.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;When temperatures are very high, relative humidity can under represent how much moisture there is in the air, making dew point the better measure.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2020-01-31T11:19:40.043" LastActivityDate="2020-01-31T11:19:40.043" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18349" PostTypeId="2" ParentId="18340" CreationDate="2019-10-31T18:52:19.103" Score="2" Body="&lt;p&gt;With fires, the forest cover and climate generally control what are the worse seasons for fires, add to this the human factor, accidental and prescribed burning.  For purposely ignited fires spring and fall are the major seasons, spring because the ground is often still damp but the fine fuels on the surface are dry enough to burn, making the fire easier to control, fall because the fuel is generally dry but the weather is getting colder and wetter with winter approaching making the fire easier to extinguish and reducing the time required to monitor the fire.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case of the Smoky mountains, it appears that the weather is more damp, humid, in the winter and summer, additionally, summer has more moderating green moist vegetation that is not present in the spring or fall.  The following excerpt from the Great Smokey Mountains Fire management plan directly mentions the spring and fall seasons (See page 16).  &lt;a href=&quot;https://www.nps.gov/aboutus/foia/upload/grsm_firemanagementplan_Section508.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Great Smoke Mountains Fire Management Plan&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The annual fire weather cycle is more a function of seasonality and temperature than&#xA;  precipitation. Warm temperatures and exposed fuels during the dormant seasons of spring and&#xA;  fall condition the fuels for easy ignition and spread. In contrast, during the winter, cold&#xA;  temperatures prolong the wetting effect of the precipitation, and in the summer, heavy sheltering&#xA;  of fuels by tree foliage (coupled with high humidity) makes for poor ignition conditions under&#xA;  normal circumstances. Exceptions to the norm have occurred. Atypical dry spells in any&#xA;  season can result in more fires and/or unusually higher fire intensities. In 1987, and again in&#xA;  2007, extreme summer-time droughts made the normally fire-resistant hardwood forest&#xA;  susceptible to fire. Numerous lightning- and human-caused fires in and near the Park burned&#xA;  thousands of acres during summer months in those years. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user824" LastActivityDate="2019-10-31T18:52:19.103" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18350" PostTypeId="1" CreationDate="2019-10-31T19:02:00.340" Score="1" ViewCount="223" Body="&lt;h1&gt;Here is my logic (thus not opinion) if the anthropogenic global heating AGH deniers actually do not have any rational climate science basis for rejecting anthropogenic global heating then everyone should understand that their position is baseless.&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;It would seem that consistent failure by global heating deniers to provide a rational basis for their rejection of climate science would form sufficient evidence that no such rational basis exists.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am diligently striving to use logical analysis to cut to the heart of the truth about global heating in such a way that all true skeptics (not those hired to lie) will immediately see the light of the truth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I make this post so that all global heating deniers will be provided an opportunity to present their side. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If such a rational basis exists, then it can be provided. If it cannot be provided then no such rational basis exists. &lt;strong&gt;If no such rational basis for rejecting climate science exists then the matter of: anthropogenic global heating (AGH) is concluded in closure.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;3C ± 1.5C for every doubling of CO2 plus the following 100 PPM spike in global CO2 since 1950 really seem to explain the temperature increase.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we apply climate sensitivity analysis to the current level of atmospheric CO2 we find that this increase of CO2 predicts a temperature equilibrium of +1.65C: 3 * log2(410 / 280) = 1.65C. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_sensitivity#Intergovernmental_Panel_on_Climate_Change&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Climate_sensitivity#Intergovernmental_Panel_on_Climate_Change&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9wDcP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9wDcP.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/t0e3c.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/t0e3c.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17970" LastEditorUserId="17970" LastEditDate="2019-11-02T02:40:17.603" LastActivityDate="2019-11-02T02:40:17.603" Title="What could possibly be a rational basis for rejecting climate science?" Tags="|climate-change|" AnswerCount="2" CommentCount="21" ClosedDate="2019-11-01T08:49:22.673" ContentLicense="CC BY-SA 4.0" />
  <row Id="18351" PostTypeId="2" ParentId="18350" CreationDate="2019-10-31T23:19:07.673" Score="-7" Body="&lt;p&gt;Just because someone says that man made CO2 emissions are not the sole cause of climate warming does not mean they are rejecting climate science. On the contrary, it is those who claim it is the sole cause who are rejecting science. Prof.Malte Janson of the University of Chicago, quoted in the journal Nature Geoscience, is among those who say man made CO2 is not the sole cause of climate warming, but his academic status will probable deter the climate fanatics from labelling him an heretic and climate change denier.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Jensen's team have found that increase or decrease of sea ice in the Southern Ocean around Antarctica plays an important part in the CO2 content of the atmosphere. When there is an increase in sea ice, the ocean beneath the ice can no longer release CO2 into the atmosphere, and that, in addition to the ice reflecting solar radiation back into space, causes cooling. When the sea ice retreats, the opposite effect occurs: CO2 is released and there is also less reflectivity, so the world warms up. This helps explain why the Milankovitch cycles are not an infallible guide as to when ice ages will occur.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Between 1979 and 2014, ice cover in the Southern Ocean increased, and had this trend continued, then according to Prof.Jansen it might have eventually led to the start of a mini ice age or worse, but from 2014 to the present time the ice has been retreating. No one is sure what will happen next, whether the ice will continue to retreat or resume its advance. According to the researchers, the Younger Dryas climate event of  about 12,800 years ago may have been caused by a sea ice advance of this sort. It is also a possible cause of the 400 year Little Ice Age from roughly AD 1400 to AD 1800. The point I am making is that many so-called climate change deniers are in fact nothing of the sort, they are just less fanatical than those who have made climate change their religion.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-10-31T23:19:07.673" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18352" PostTypeId="2" ParentId="18350" CreationDate="2019-10-31T23:43:11.737" Score="0" Body="&lt;p&gt;If the issue is assessed on other grounds than science ones there can be rational reasons to reject climate science. e.g. if it is being assessed with respect to how addressing versus not addressing AGW impacts costs, competitiveness and profitability of specific business enterprises then rejecting climate science and encouraging other business operators as well as governments, courts and regulators to reject it, to avoid compliance costs of addressing it appears rational. The advice given by lawyers to people and companies facing lawsuits to admit no responsibility and seek to undermine the plaintiff's arguments, including questioning the veracity of expert witnesses is not irrational. Unethical perhaps, but it is not irrational.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2019-10-31T23:43:11.737" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18354" PostTypeId="1" AcceptedAnswerId="18357" CreationDate="2019-11-01T02:52:51.423" Score="14" ViewCount="8667" Body="&lt;p&gt;Why are some gases Greenhouse gases while some are not?&lt;/p&gt;&#xA;&lt;p&gt;I did search this on the net but didn't get any clearcut/credible answers.&lt;/p&gt;&#xA;&lt;p&gt;What exactly is the property that is common among Ozone, Water Vapour, CFCs, and Methane that makes them all greenhouse gases?&lt;/p&gt;&#xA;" OwnerUserId="18178" LastEditorUserId="543" LastEditDate="2021-05-24T04:58:10.327" LastActivityDate="2021-05-24T04:58:10.327" Title="Why is Carbon Dioxide a Greenhouse Gas whereas Ammonia is not?" Tags="|greenhouse-gases|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18356" PostTypeId="2" ParentId="18354" CreationDate="2019-11-01T03:06:19.263" Score="7" Body="&lt;p&gt;The common factor among Greenhouse gases is that they absorb and scatter infra-red light.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Greenhouse effect is caused when energy coming in from the sun is prevented from escaping again.  The Sun emits light primarily in the visible spectrum, with some UV and infra-red, most of which is absorbed by the Earth.  This causes the Earth to heat up and in turn release it's own black body radiation, which at the temperature of the Earths surface is primarily infra-red.  This outgoing radiation is the only way the Earth can cool itself, and the stable temperature at the surface is that at which the outgoing energy of Earths black body radiation exactly matches the incoming energy from the sun which is absorbed (plus a relatively very small amount released from the Earths core).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A Greenhouse gas is one which allows less of this infra-red light back out into space, causing it to be reabsorbed and raising the temperature of the planet.  Similarly, any gas which primarily blocks visible or UV light has a cooling effect, since it blocks more incoming energy from the sun than outgoing energy from Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6174548/&quot; rel=&quot;noreferrer&quot;&gt;Here&lt;/a&gt; is a paper with a very nice diagram showing off the absorption spectrum of several gasses.  It's worth noting that water vapor is an even stronger Greenhouse gas than Carbon Dioxide, but since its concentration in the atmosphere is largely affected by temperature it is less concerning as a waste product we produce than it is as a positive feedback mechanism.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Greenhouse gases will have an effect as long as they exist in the atmosphere.  Methane is a famous example of a greenhouse gas with a warming potential of about 30 times CO2 over 100 years, but over 20 years has a warming potential 86 times higher than CO2.  The large difference over the long time period is because CO2 is very stable, but Methane has a lifetime in the atmosphere of only 12 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ammonia has a lifetime in the atmosphere of only one week.  &lt;strike&gt;The primary reason for this is the highly reactive nature of Nitrogen-Hydrogen bonds.  These bonds tend to be quite weak, and are commonly found in explosives because of how quickly they decompose.&lt;/strike&gt;  I was mistaken, &lt;a href=&quot;https://www.esrl.noaa.gov/csd/aqrsd/reports/ammonia.pdf&quot; rel=&quot;noreferrer&quot;&gt;the primary reason is that Ammonia is highly water soluble so quickly comes down in rain, and is also readily absorbed by plants&lt;/a&gt;.  N-H bonds are not especially weak, but Nitrogen tends to prefer to be in its extremely stable N2 state.  The difference in strength between the bonds in these forms is what makes Nitrogen compounds so explosive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because Ammonia is so short lived in the atmosphere, it has an effective global warming potential of zero, despite absorbing the right frequencies of infra-red radiation to otherwise be a greenhouse gas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: I should also say since you mention CFCs and Ozone in your question: CFCs are not concerning as a Greenhouse gas, they erode the Ozone layer.  The Ozone layer itself has little to do with the Greenhouse effect, but instead is involved in blocking UV light which is damaging to living things on the planet (for example, causes skin cancer).  Since Ozone blocks UV, it is a gas which cools rather than warms the Earth, though I am not certain how strong the effect is.  I imagine not very since I've never seen it mentioned.&lt;/p&gt;&#xA;" OwnerUserId="18179" LastEditorUserId="18179" LastEditDate="2019-11-01T12:18:48.733" LastActivityDate="2019-11-01T12:18:48.733" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="18357" PostTypeId="2" ParentId="18354" CreationDate="2019-11-01T03:14:11.993" Score="22" Body="&lt;p&gt;A molecular gas is a good infrared absorber if it has several atoms (not just 2, like O&lt;sub&gt;2&lt;/sub&gt; and N&lt;sub&gt;2&lt;/sub&gt;) or if it is hetero-nuclear (e.g. CO and NO).  These type of molecular arrangements allow more infrared energy to be absorbed because there are more &lt;a href=&quot;https://scied.ucar.edu/molecular-vibration-modes&quot; rel=&quot;nofollow noreferrer&quot;&gt;vibrational states&lt;/a&gt; that are possible.  Yes, ammonia fits that description, but it is not long-lived in the atmosphere and it is not widespread.  So, even though ammonia is a &lt;a href=&quot;https://www.researchgate.net/figure/Infrared-absorption-spectra-of-water-vapor-and-several-gases-that-may-contribute-to_fig1_11295855&quot; rel=&quot;nofollow noreferrer&quot;&gt;good infrared absorber&lt;/a&gt;, it is not an important greenhouse gas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ammonia in the atmosphere is very reactive, and will form to make nitrates and sulfates while in solution (e.g. in cloud droplets).  Thus, the atmospheric lifetime of ammonia is short-lived, whereas most important greenhouse gases are long-lived and not reactive.  For global  warming discussion, you would likely associate ammonia with a net cooling effect since the increased formation of particulate (clouds/haze) increases the albedo of the Earth (which scatters light back to space).&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="20" LastEditDate="2019-11-04T09:07:01.243" LastActivityDate="2019-11-04T09:07:01.243" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="18360" PostTypeId="1" CreationDate="2019-11-01T21:35:12.907" Score="1" ViewCount="73" Body="&lt;p&gt;I should make a &lt;strong&gt;short-term forecast&lt;/strong&gt; of Europe by using synoptic charts. I'm finding it really hard so I'd be glad if you help me. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WFwyX.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WFwyX.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/PZeWG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PZeWG.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/z4oQr.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/z4oQr.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;'В' means high atmospheric pressure&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;I'm trying to figure out the legend of the chart, and I hope I did it right:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;White: wind&lt;/li&gt;&#xA;&lt;li&gt;Blue: rainfall&lt;/li&gt;&#xA;&lt;li&gt;Orange: clouds&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I'd appreciate it if you give me some hints. Thank you!&lt;/p&gt;&#xA;" OwnerUserId="18191" LastEditorDisplayName="user1066" LastEditDate="2019-11-03T07:16:21.787" LastActivityDate="2019-11-03T07:16:21.787" Title="Short-term forecast of Europe by using synoptic charts" Tags="|meteorology|wind|clouds|weather-forecasting|rainfall|" AnswerCount="0" CommentCount="15" ContentLicense="CC BY-SA 4.0" />
  <row Id="18361" PostTypeId="1" CreationDate="2019-11-02T13:46:44.200" Score="1" ViewCount="1014" Body="&lt;p&gt;I wish to plot seismic waveform data using Obspy, bu they are in Ascii format. Is it possible to read and plot Ascii file using Obspy?&lt;/p&gt;&#xA;" OwnerUserId="18198" LastActivityDate="2020-04-18T16:02:25.340" Title="How to read and plot seismic waveform data in Ascii format using Obspy?" Tags="|seismology|python|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18362" PostTypeId="1" CreationDate="2019-11-02T17:35:33.507" Score="1" ViewCount="370" Body="&lt;h1&gt;Does extrapolating current CO2 trends indicate 7632 PPM CO2 and 14C temperature anomaly within 200 years?&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;It looks like simply extrapolating the current trends of increasing atmospheric CO2 would show that totally unmitigated green house gas emissions (for the next 200 years) would result in more drastic climate change than ever seen in the last 600 million years. This period included several very extreme extinction events.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3.32 PPM annual CO2 increase compounded at the 1.9% annual growth rate derives 7632 PPM from the current 410 PPM. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This CO2 increase over preindustrial CO2 levels of 280 PPM derives a 3 * log2(7632 / 280) = 14.3C temperature anomaly over the 14C base temperature. 14C + 14C = 28C hotter than any time in the last 600 million years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This derivation uses the current standard logarithmic casual relationship between increases in CO2 and global temperature: 3C ± 1.5C per CO2 doubling. &lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_sensitivity#Intergovernmental_Panel_on_Climate_Change&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Climate_sensitivity#Intergovernmental_Panel_on_Climate_Change&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Below shows the basis of the extrapolated 7632 PPM CO2 calculations and a full table of each annual increment to global CO2 for the next 200 years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.co2.earth/co2-acceleration#&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.co2.earth/co2-acceleration#&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Oct  31  2019: 409.64 ppm&amp;lt;br&amp;gt;&#xA;Oct  31  2018: 406.32 ppm&amp;lt;br&amp;gt;&#xA;3.32 CO2 Growth&amp;lt;br&amp;gt;&#xA;&#xA;2014 2.11 ppm&amp;lt;br&amp;gt;&#xA;1959 0.73 ppm&amp;lt;br&amp;gt;&#xA;  55 2.89 growth factor&amp;lt;br&amp;gt;&#xA;1.019 ^ 55 = 2.81 growth factor&amp;lt;br&amp;gt;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Thus a 1.9% annual acceleration to the current 3.32 PPM CO2 growth rate&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Applying accelarating CO2 growth rate to current CO2 levels for 200 years: in 2219 we would have 7632 ppm of CO2. (See table). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;3C ± 1.5C per CO2 doubling we derive: &lt;br&gt;&#xA;3 * log2(7632 / 280) = 14.3C tempeature anomaly from 14C base.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;28C is hotter than any time in the last 600 million years, thus the next 200 years of utterly unmitigated green house gas emissions would cause the most drastic climate change in 600 million years if we merely extrapolate the current trends. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;If I got my {facts, climate science, math} correctly and CO2 continues to increase at its current accelerating rate for 200 years then the world will experience greater climate change than at anytime in the prior 600 million years.&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Apparently we are already emitting much more than the 28GT RPC8.5 levels&lt;/strong&gt;&lt;br&gt;&#xA;&lt;a href=&quot;https://judithcurry.com/2018/11/24/is-rcp8-5-an-impossible-scenario/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://judithcurry.com/2018/11/24/is-rcp8-5-an-impossible-scenario/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Z54Wc.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Z54Wc.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;My year 2100 emission projection of 1008 PPM matches RCP8.5&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pX8tY.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pX8tY.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;CO2_growth over 200 years at currently accelerating rate&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;&lt;pre&gt;&lt;code&gt;  1       3.32   409.64&#xA;  2       3.38   412.96&#xA;  3       3.45   416.34&#xA;  4       3.51   419.79&#xA;  5       3.58   423.30&#xA;  6       3.65   426.88&#xA;  7       3.72   430.53&#xA;  8       3.79   434.25&#xA;  9       3.86   438.03&#xA; 10       3.93   441.89&#xA; 11       4.01   445.83&#xA; 12       4.08   449.83&#xA; 13       4.16   453.92&#xA; 14       4.24   458.08&#xA; 15       4.32   462.32&#xA; 16       4.40   466.64&#xA; 17       4.49   471.04&#xA; 18       4.57   475.53&#xA; 19       4.66   480.10&#xA; 20       4.75   484.76&#xA; 21       4.84   489.51&#xA; 22       4.93   494.35&#xA; 23       5.02   499.28&#xA; 24       5.12   504.30&#xA; 25       5.22   509.42&#xA; 26       5.31   514.63&#xA; 27       5.42   519.95&#xA; 28       5.52   525.36&#xA; 29       5.62   530.88&#xA; 30       5.73   536.51&#xA; 31       5.84   542.24&#xA; 32       5.95   548.08&#xA; 33       6.06   554.03&#xA; 34       6.18   560.09&#xA; 35       6.30   566.27&#xA; 36       6.42   572.56&#xA; 37       6.54   578.98&#xA; 38       6.66   585.52&#xA; 39       6.79   592.18&#xA; 40       6.92   598.97&#xA; 41       7.05   605.88&#xA; 42       7.18   612.93&#xA; 43       7.32   620.12&#xA; 44       7.46   627.43&#xA; 45       7.60   634.89&#xA; 46       7.74   642.49&#xA; 47       7.89   650.24&#xA; 48       8.04   658.13&#xA; 49       8.19   666.17&#xA; 50       8.35   674.36&#xA; 51       8.51   682.71&#xA; 52       8.67   691.22&#xA; 53       8.83   699.89&#xA; 54       9.00   708.73&#xA; 55       9.17   717.73&#xA; 56       9.35   726.90&#xA; 57       9.53   736.25&#xA; 58       9.71   745.78&#xA; 59       9.89   755.48&#xA; 60      10.08   765.37&#xA; 61      10.27   775.45&#xA; 62      10.47   785.72&#xA; 63      10.66   796.19&#xA; 64      10.87   806.85&#xA; 65      11.07   817.72&#xA; 66      11.28   828.79&#xA; 67      11.50   840.08&#xA; 68      11.72   851.58&#xA; 69      11.94   863.29&#xA; 70      12.17   875.23&#xA; 71      12.40   887.40&#xA; 72      12.63   899.80&#xA; 73      12.87   912.43&#xA; 74      13.12   925.30&#xA; 75      13.37   938.42&#xA; 76      13.62   951.79&#xA; 77      13.88   965.41&#xA; 78      14.14   979.29&#xA; 79      14.41   993.43&#xA; 80      14.69   1007.84&#xA; 81      14.96   1022.53&#xA; 82      15.25   1037.49&#xA; 83      15.54   1052.74&#xA; 84      15.83   1068.28&#xA; 85      16.14   1084.11&#xA; 86      16.44   1100.25&#xA; 87      16.75   1116.69&#xA; 88      17.07   1133.45&#xA; 89      17.40   1150.52&#xA; 90      17.73   1167.91&#xA; 91      18.06   1185.64&#xA; 92      18.41   1203.71&#xA; 93      18.76   1222.11&#xA; 94      19.11   1240.87&#xA; 95      19.48   1259.98&#xA; 96      19.85   1279.46&#xA; 97      20.22   1299.31&#xA; 98      20.61   1319.53&#xA; 99      21.00   1340.14&#xA;100      21.40   1361.14&#xA;101      21.81   1382.54&#xA;102      22.22   1404.34&#xA;103      22.64   1426.56&#xA;104      23.07   1449.20&#xA;105      23.51   1472.27&#xA;106      23.96   1495.78&#xA;107      24.41   1519.74&#xA;108      24.88   1544.15&#xA;109      25.35   1569.03&#xA;110      25.83   1594.38&#xA;111      26.32   1620.21&#xA;112      26.82   1646.53&#xA;113      27.33   1673.35&#xA;114      27.85   1700.68&#xA;115      28.38   1728.53&#xA;116      28.92   1756.91&#xA;117      29.47   1785.82&#xA;118      30.03   1815.29&#xA;119      30.60   1845.32&#xA;120      31.18   1875.92&#xA;121      31.77   1907.10&#xA;122      32.38   1938.87&#xA;123      32.99   1971.24&#xA;124      33.62   2004.23&#xA;125      34.26   2037.85&#xA;126      34.91   2072.11&#xA;127      35.57   2107.01&#xA;128      36.25   2142.58&#xA;129      36.93   2178.83&#xA;130      37.64   2215.77&#xA;131      38.35   2253.40&#xA;132      39.08   2291.75&#xA;133      39.82   2330.83&#xA;134      40.58   2370.66&#xA;135      41.35   2411.24&#xA;136      42.14   2452.59&#xA;137      42.94   2494.72&#xA;138      43.75   2537.66&#xA;139      44.58   2581.41&#xA;140      45.43   2625.99&#xA;141      46.29   2671.42&#xA;142      47.17   2717.72&#xA;143      48.07   2764.89&#xA;144      48.98   2812.96&#xA;145      49.91   2861.94&#xA;146      50.86   2911.86&#xA;147      51.83   2962.72&#xA;148      52.81   3014.55&#xA;149      53.82   3067.36&#xA;150      54.84   3121.18&#xA;151      55.88   3176.02&#xA;152      56.94   3231.90&#xA;153      58.02   3288.84&#xA;154      59.13   3346.87&#xA;155      60.25   3405.99&#xA;156      61.40   3466.25&#xA;157      62.56   3527.64&#xA;158      63.75   3590.20&#xA;159      64.96   3653.95&#xA;160      66.20   3718.92&#xA;161      67.45   3785.11&#xA;162      68.74   3852.57&#xA;163      70.04   3921.30&#xA;164      71.37   3991.34&#xA;165      72.73   4062.72&#xA;166      74.11   4135.44&#xA;167      75.52   4209.55&#xA;168      76.95   4285.07&#xA;169      78.42   4362.03&#xA;170      79.91   4440.44&#xA;171      81.42   4520.35&#xA;172      82.97   4601.77&#xA;173      84.55   4684.74&#xA;174      86.15   4769.29&#xA;175      87.79   4855.44&#xA;176      89.46   4943.23&#xA;177      91.16   5032.69&#xA;178      92.89   5123.85&#xA;179      94.65   5216.74&#xA;180      96.45   5311.39&#xA;181      98.29   5407.85&#xA;182     100.15   5506.13&#xA;183     102.06   5606.28&#xA;184     104.00   5708.34&#xA;185     105.97   5812.34&#xA;186     107.98   5918.31&#xA;187     110.04   6026.29&#xA;188     112.13   6136.33&#xA;189     114.26   6248.46&#xA;190     116.43   6362.71&#xA;191     118.64   6479.14&#xA;192     120.89   6597.78&#xA;193     123.19   6718.68&#xA;194     125.53   6841.87&#xA;195     127.92   6967.40&#xA;196     130.35   7095.32&#xA;197     132.82   7225.67&#xA;198     135.35   7358.49&#xA;199     137.92   7493.84&#xA;200     140.54   7631.76&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="17970" LastEditorUserId="17970" LastEditDate="2019-11-05T05:22:02.570" LastActivityDate="2020-01-04T19:51:09.433" Title="Does extrapolating current CO2 trends indicate 7632 PPM CO2 and 14C temperature anomaly within 200 years?" Tags="|climate-change|" AnswerCount="3" CommentCount="15" ContentLicense="CC BY-SA 4.0" />
  <row Id="18363" PostTypeId="2" ParentId="18362" CreationDate="2019-11-02T22:12:12.417" Score="1" Body="&lt;p&gt;As a thought experiment it may tell us something about why simplistic extrapolation is inadequate for climate change prediction. Climate modelling of extreme scenarios might be compared and contrasted with simple extrapolation, but is more likely to show deficits in such extrapolation than in the modelling. It cannot work as prediction because there are very significant real world factors and constraints - physical, economic, societal - at work that are not included, that mean simple extrapolation will almost certainly be wrong.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2019-11-02T22:12:12.417" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18364" PostTypeId="2" ParentId="18354" CreationDate="2019-11-03T01:25:52.860" Score="4" Body="&lt;p&gt;A gas is generally considered a &lt;a href=&quot;https://en.wikipedia.org/wiki/Greenhouse_gas&quot; rel=&quot;nofollow noreferrer&quot;&gt;greenhouse gas&lt;/a&gt; (&lt;em&gt;GHG&lt;/em&gt;) if it meets both the following conditions:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;GHG molecules absorb and emit &lt;a href=&quot;https://en.wikipedia.org/wiki/Electromagnetic_radiation&quot; rel=&quot;nofollow noreferrer&quot;&gt;electromagnetic radiation&lt;/a&gt; in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Infrared&quot; rel=&quot;nofollow noreferrer&quot;&gt;infrared (&lt;em&gt;IR&lt;/em&gt;) range&lt;/a&gt;. GHG molecules can do this because they have &lt;a href=&quot;https://scied.ucar.edu/molecular-vibration-modes&quot; rel=&quot;nofollow noreferrer&quot;&gt;vibrational states&lt;/a&gt; that can store energy when absorbing a photon with an IR energy level (~1-1600 meV), especially those with the subset of IR energy levels (&lt;em&gt;longwave&lt;/em&gt; or &lt;em&gt;thermal infrared&lt;/em&gt;) most often encountered on Earth (~80-160 meV).&lt;/li&gt;&#xA;&lt;li&gt;GHG molecules are found in sufficiently large amounts in the Earth's atmosphere to produce significant &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiative_forcing&quot; rel=&quot;nofollow noreferrer&quot;&gt;radiative forcing&lt;/a&gt; (which is the preferred way of saying &quot;greenhouse effect&quot;). This can be either because there are large sources of the gas, or the gas is sufficiently long-lived to accumulate in the atmosphere, or both.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Like any classification, this is somewhat arbitrary: any two scientists may disagree on what counts as sufficient absorbing or accumulating for any given &lt;a href=&quot;https://en.wikipedia.org/wiki/Chemical_species&quot; rel=&quot;nofollow noreferrer&quot;&gt;atmospheric species&lt;/a&gt;. But in practice, the earth-science community tends to agree.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ammonia (NH&lt;sub&gt;3&lt;/sub&gt;) molecules &lt;a href=&quot;https://www.researchgate.net/figure/Infrared-absorption-spectra-of-water-vapor-and-several-gases-that-may-contribute-to_fig1_11295855&quot; rel=&quot;nofollow noreferrer&quot;&gt;absorb infrared well&lt;/a&gt;, so they meet condition 1, but they are also &lt;em&gt;very&lt;/em&gt; reactive, particularly in aqueous solution (e.g., in cloud droplets). Hence they don't survive long enough to accumulate, and thus fail condition 2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By contrast, ozone (O&lt;sub&gt;3&lt;/sub&gt;), water vapor (H&lt;sub&gt;2&lt;/sub&gt;O), methane (CH&lt;sub&gt;4&lt;/sub&gt;), and CFCs (which are a group of species) are all generally regarded as meeting both these conditions.&lt;/p&gt;&#xA;" OwnerUserId="4503" LastActivityDate="2019-11-03T01:25:52.860" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18365" PostTypeId="2" ParentId="18362" CreationDate="2019-11-03T06:47:17.780" Score="2" Body="&lt;p&gt;It looks as if you are assuming a constant percentage increase, compounded annually. There are many reasons why this is not so. It reminds me of many decades ago when I routinely weighed my baby son. On the basis of his rate of growth I calculated that he would weigh 2660 kg by the age of 3! So much for simple extrapolation.&#xA;Humans are already using vastly more than the renewable rate of resource consumption, so it is obvious that our population cannot continue to grow at anything like the historic rates. In particular, the rate of carbon emissions is slowing; not by anything like fast enough, but slowing nevertheless. &#xA;Then there are the climate change feedback processes that will kick in sooner or later. Some are probably beginning already. By my estimation there are at least 16 feedback processes, a mix of positive and negative, but mostly positive. None of them are adequately calibrated. In short, future atmospheric &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; levels will be the product of a host of non-linear processes. It would be rash of anyone to try and predict far into the next century. That said, if I was absolutely forced to project so far into the future, I would try to adapt the graph of the last few thousand  years of atmospheric &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; to an error function curve. But then you would be forced into an extrapolation in which the error bounds far exceed the final quasi-equilibrium &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; concentration. In other words, it would be a meaningless exercise. &#xA;We will all be in deep trouble if the &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; reaches even 760 ppm, let alone 7600+ of your estimate! I find it scary enough that we are still on an RCP trajectory that is closer to 8.5 than any of the other 'standard scenarios'. Present reality is alarming enough without speculating on fantastic projections.&lt;/p&gt;&#xA;" OwnerUserId="4507" LastEditorUserId="2470" LastEditDate="2020-01-04T19:45:04.507" LastActivityDate="2020-01-04T19:45:04.507" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18366" PostTypeId="2" ParentId="18341" CreationDate="2019-11-03T07:05:22.910" Score="1" Body="&lt;p&gt;There is no such simple relationship between rainfall and runoff (I wish there was!).&#xA;How much of the rainfall ends up as runoff depends upon at least the following variables:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;temperature,&#xA;humidity,&#xA;wind-run,&#xA;hours per day of bright sunshine, &#xA;latitude,&#xA;altitude,&#xA;type and density of vegetation cover,&#xA;soil type, thickness and consistency,&#xA;antecedent conditions,&#xA;soil moisture content,&#xA;land slope and orientation with respect to the sun,&#xA;underlying geology (lithology, structure, connectivity with surface soils, degree of weathering),&#xA;degree of urbanization,&#xA;heat island effect,&#xA;human intervention,&#xA;seasonality.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is why all catchment models used to estimate the overall rainfall-runoff have to be carefully calibrated using rainfall AND runoff time-series of data. You can't do it by remote sensing. For all the fancy gimmicks and new equipment there is no substitute for boots on the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Golden Rule Nr 1: you can't manage what you don't understand&lt;/p&gt;&#xA;&#xA;&lt;p&gt;GRNr2: You can't understand it unless you measure it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;GRNr3: You can't measure it by sitting in an office. &lt;/p&gt;&#xA;" OwnerUserId="4507" LastActivityDate="2019-11-03T07:05:22.910" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18367" PostTypeId="2" ParentId="18362" CreationDate="2019-11-03T11:09:43.357" Score="1" Body="&lt;p&gt;A linear correlation can not be done as the atmosphere have not a linear progression. Take a look to this interested &lt;a href=&quot;http://climatemodels.uchicago.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt; to these Chicago University Climate Models Webpage. The first one you should check is &lt;a href=&quot;http://climatemodels.uchicago.edu/modtran/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First of all, &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; is acting as a Greenhouse Effect Gas because it is absorbing some of the infrared radiation that it is trying to leave the Earth. &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; it is just absorving this radiation and bringing back to the surface (as well as &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{H_2O}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CH_4}$&lt;/span&gt;...).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the natural cooling system of our planet is disturbed by all this gases. But there is a limit for all of them. The gas is not acquiring all the energy, just a range (Band Saturation). So it can absorb just some of the energy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let´s see one example: Considering no &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CH_4}$&lt;/span&gt; collaboration or &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{H_2O}$&lt;/span&gt;... Same point on different latitudes...&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;| CO2 CONCENTRATION   |        |         |         |        |        |        |        |        |        |        |        |&#xA;|---------------------|--------|---------|---------|--------|--------|--------|--------|--------|--------|--------|--------|&#xA;| (Energy in W/m2)    | 0      | 10      | 50      | 100    | 200    | 400    | 800    | 1600   | 3200   | 6400   | 12800  |&#xA;|---------------------|--------|---------|---------|--------|--------|--------|--------|--------|--------|--------|--------|&#xA;| Tropical Atmosphere | 339.12 | 325.62  | 317.45  | 313.84 | 310.39 | 306.97 | 303.51 | 299.93 | 296.10 | 291.93 | 287.15 |&#xA;| MidLattitude Summer | 328.13 | 315.57  | 307.908 | 304.77 | 301.69 | 298.61 | 295.44 | 292.21 | 288.82 | 285.21 | 281.16 |&#xA;| MidLattitude Winter | 264.36 | 254.59  | 248.97  | 246.62 | 244.23 | 241.81 | 239.33 | 236.79 | 234.28 | 231.73 | 229.00 |&#xA;| Subartic Summer     | 303.29 | 292.271 | 286.12  | 283.61 | 281.12 | 278.61 | 276.04 | 273.46 | 270.89 | 268.19 | 265.14 |&#xA;| Subartic Winter     | 222.38 | 215.53  | 211.48  | 209.82 | 208.15 | 206.39 | 204.57 | 202.75 | 201.02 | 199.36 | 197.69 |&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;With this figures, we can see that it is a linear regression: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/S3H0F.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/S3H0F.png&quot; alt=&quot;FIGURES&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But as soon as we are absorbing energy, we need more &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; to increase the amount. For example, the preindustrial readings were 280 ppm until the actual 400 ppm, with this amount of energy retained, you have the actual temperature increasing. In order to collect the same amount of energy (so in order to increase the temperature) we need to reach 608 ppm:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;| CO2 Increasing      | 200-400 | 400-800 |   | 400-608 |       |&#xA;|---------------------|---------|---------|---|---------|-------|&#xA;| Tropical Atmosphere | 3,42    | 3,46    |   | 1,76    | 51,0% |&#xA;| MidLattitude Summer | 3,08    | 3,17    |   | 1,57    | 50,4% |&#xA;| MidLattitude Winter | 2,42    | 2,48    |   | 1,26    | 51,3% |&#xA;| Subartic Summer     | 2,51    | 2,57    |   | 1,32    | 52,0% |&#xA;| Subartic Winter     | 1,76    | 1,82    |   | 0,91    | 51,0% |&#xA;| Average             | 2,77    | 2,83    |   | 1,43    | 51,1% |&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;So the concentration is growing linearly, but that is not the case of energy and temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can not make a simple correlation because the temperature depends of: &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{H_2O}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CH_4}$&lt;/span&gt;, Ozone, Aerosols, Sun Energy Emission, Clouds, Latitude, Ground colour... So it is not just a number.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main uncertainty on the Greenhouse Effect are clouds. Check the different models and you will see that a 2X concentration growing can increase the energy on 3-4 &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{W/m^2}$&lt;/span&gt;, clouds can reduce/increase from -17 W to +5 W. Considering your figures, with a 3.32 ppm/year growing, in order to get the temperature increasing from preindustrial area until now, you will reach 2079. If we reduce the growing, this period will be extended.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are some more problems that just &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;: &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CH_4}$&lt;/span&gt;, Permafrost areas, high altitude clouds...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I recommend you this &lt;a href=&quot;https://pdfs.semanticscholar.org/7de3/0f30e44a42899effa2e1dda947c2d22f79eb.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;reading&lt;/a&gt; from David Archer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope it helps&lt;/p&gt;&#xA;" OwnerUserId="18035" LastEditorUserId="2470" LastEditDate="2020-01-04T19:51:09.433" LastActivityDate="2020-01-04T19:51:09.433" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="18368" PostTypeId="1" CreationDate="2019-11-03T12:21:14.607" Score="1" ViewCount="112" Body="&lt;p&gt;From what I know from various textbooks, pop-science shows and my classes, the earth's core is solid. But how does the concept of solid and liquid make sense at these high temperatures.&lt;/p&gt;&#xA;" OwnerUserId="18200" LastActivityDate="2019-11-03T13:53:58.067" Title="On the solidity of the Earth's core" Tags="|temperature|core|" AnswerCount="1" CommentCount="0" ClosedDate="2019-11-03T21:46:30.537" ContentLicense="CC BY-SA 4.0" />
  <row Id="18369" PostTypeId="2" ParentId="18368" CreationDate="2019-11-03T13:53:58.067" Score="1" Body="&lt;p&gt;The Earth's core is both solid and liquid. The outer core is molten and produces currents of molten nickel/iron which generate the Earth's magnetic field in a dynamo effect, while the inner core is solid. The reason the inner core is solid is that it is under tremendous pressure, more so than the outer core. Scientists know this from the analysis of seismic waves which pass through the Earth.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-03T13:53:58.067" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18370" PostTypeId="2" ParentId="18361" CreationDate="2019-11-03T16:49:21.410" Score="0" Body="&lt;p&gt;good question. I don't have much experience with &lt;a href=&quot;https://github.com/obspy/obspy/wiki&quot; rel=&quot;nofollow noreferrer&quot;&gt;obspy&lt;/a&gt; specifically - nonetheless, I have been unable to locate &lt;em&gt;any&lt;/em&gt; functionality to do some kind of TXT to SEGY/SEGD/SEG2 conversion with this particular Python package, which is interesting. I truly doubt obspy is missing this kind of tool. But, in the unlikely and unfortunate case that this mauy be indeed true, I'll list some other (hopefully) viable options for you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not all is lost, though. I have done this many times before but &lt;em&gt;NOT&lt;/em&gt; with &lt;strong&gt;obspy&lt;/strong&gt;. I have used &lt;a href=&quot;https://en.wikipedia.org/wiki/Seismic_Unix&quot; rel=&quot;nofollow noreferrer&quot;&gt;SeismicUnix&lt;/a&gt; before to do this via &lt;a href=&quot;http://web.mit.edu/cwpsu_v44r1/sumanual_600dpi_letter.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;A2B&lt;/a&gt; functionality. Also, I have used both &lt;a href=&quot;https://www.mathworks.com/matlabcentral/fileexchange/53109-seislab-3-02&quot; rel=&quot;nofollow noreferrer&quot;&gt;SeisLab&lt;/a&gt; (a MATLAB package) and &lt;a href=&quot;https://dgbes.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;OpendTect&lt;/a&gt; to do this. Note that which tool is best is somewhat dependent on what kinda of seismic data you have. For example, if you are looking at a single trace, one software package and/or code may be better suited to solve you problems than if your data are many traces, especially if there are 3-D data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found &lt;a href=&quot;https://github.com/wassname/ascii2segy&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; and though it may be of some use to you - I have not tested it. Lastly, I don't remember, but I think &lt;a href=&quot;http://www.geogiga.com/en/frontendexpress.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;GeoGIGA&lt;/a&gt; may have a free software that included such functionality as part of its tool set.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Perhaps watching &lt;a href=&quot;https://www.youtube.com/watch?v=kFwdjfiK4gk&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; will help, too.&lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2019-11-03T16:49:21.410" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18372" PostTypeId="2" ParentId="17544" CreationDate="2019-11-04T03:23:27.897" Score="1" Body="&lt;p&gt;I've seen data like this before. My research focused on acquiring/processing both vertical and horizontal component data in subsurface environments characterized mainly by saturated and/or unconsolidated facies. So, it's entirely possible even for a that kind of surface-wave to display such low apparent velocities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I think you are seeing at that particular offset and traveltime is the Rayleigh-wave beginning to '&lt;a href=&quot;https://earthscience.stackexchange.com/questions/14414/seismic-dispersion-what-does-it-really-mean-and-what-causes-it&quot;&gt;disperse&lt;/a&gt;' - AKA seismic dispersion beginning to manifests itself as a results of the wavefield convolving with layering and near-surface heterogeneity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for a refraction arrival, if it's indeed present, it should be extremely weak and probably only discernible via some kind of gain (e.g. AGC).&lt;/p&gt;&#xA;" OwnerUserId="8447" LastEditorUserId="8447" LastEditDate="2019-11-04T03:34:26.340" LastActivityDate="2019-11-04T03:34:26.340" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18373" PostTypeId="2" ParentId="18210" CreationDate="2019-11-04T12:47:54.460" Score="2" Body="&lt;p&gt;It's hard to tell (don't you have other photos?), but it looks like magma lenses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The area is known for the Hogenakkal Carbonatite Complex, where lenses of carbonatite (a carbonate-rich magma) are found in pyroxenite dykes. See for instance &lt;a href=&quot;https://doi.org/10.1016/0301-9268(94)90104-X&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The carbonatites form a series of discontinuous bodies within two nearly parallel NNE-SSW trending pyroxenite dykes intruding Precambrian chamockites. [...] Each carbonatite body consists of discrete veins and lenses emplaced in pyroxenite which has been permeated and soaked to various degrees by the carbonatites.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But it is hard to say if this is the geological formation that you saw without more information.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2019-11-04T12:47:54.460" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18375" PostTypeId="2" ParentId="17212" CreationDate="2019-11-04T16:31:47.633" Score="1" Body="&lt;p&gt;According to @AllInOne from the comments: This is currently what a project in New York City is trying to do.&#xA;Their listed goal &lt;a href=&quot;https://en.wikipedia.org/wiki/Billion_Oyster_Project&quot; rel=&quot;nofollow noreferrer&quot;&gt;on wikipedia&lt;/a&gt; is to get one billion live oysters in New York Harbor by 2035.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://billionoysterproject.org/about/our-story/&quot; rel=&quot;nofollow noreferrer&quot;&gt;their website&lt;/a&gt;, they do this because of the following reasons:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;&lt;p&gt;Oysters have a remarkable ability to filter nitrogen pollution from water as they eat. This is a heroic feat, because excessive nitrogen&#xA;  triggers algal blooms that deplete the water of oxygen and create&#xA;  “dead zones.”&lt;/p&gt;&lt;/li&gt;&#xA;  &lt;li&gt;&lt;p&gt;“Once all but extinct in New York City’s waters, the whales are undeniably back.” –Popular Science Oysters play a key role in&#xA;  attracting life. They earn their nickname as “ecosystem engineers”&#xA;  because we see biodiversity levels increase dramatically surrounding&#xA;  oyster reefs.&lt;/p&gt;&lt;/li&gt;&#xA;  &lt;li&gt;&lt;p&gt;Oyster reefs can help to protect New York City from storm damage—softening the blow of large waves, reducing flooding, and&#xA;  preventing erosion.&lt;/p&gt;&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;the website also carries on to state that 1 million pounds of shells have also been recycled as a result of this initiative.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other comments suggest that in order to prevent invasive species, one would want to do this with oysters that already exist in the region.&lt;/p&gt;&#xA;" OwnerUserId="17150" LastActivityDate="2019-11-04T16:31:47.633" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18376" PostTypeId="1" AcceptedAnswerId="18379" CreationDate="2019-11-05T01:09:36.030" Score="1" ViewCount="396" Body="&lt;p&gt;Is it possible to build a climate-controlled greenhouse just about anywhere assuming that it contains soil-beds, a light-controlled , temperature-controlled and moisture-controlled environment and other resources needed for plants to grow?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any advantage in installing such a greenhouse on agricultural land?&lt;/p&gt;&#xA;" OwnerUserId="18212" LastActivityDate="2019-11-05T04:49:09.707" Title="Does a greenhouse need to be built on agricultural land?" Tags="|agriculture|" AnswerCount="1" CommentCount="0" ClosedDate="2019-11-05T13:43:23.407" ContentLicense="CC BY-SA 4.0" />
  <row Id="18378" PostTypeId="1" CreationDate="2019-11-05T03:37:17.503" Score="8" ViewCount="216" Body="&lt;p&gt;I am attempting to interpret an outcrop I went to. I suggested it was created by a braided stream. The one thing I cannot explain are prominent alternating siltstone and sandstone beds.  There are smaller lenses of silstone that I suggest are abandoned channel fills, but I have other siltstone beds about 0.2 - 0.5 m thick that seem pretty continuous (laterally continuous up to ~ 10-15 m as far as I can see).&lt;br /&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Ha4Hy.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ha4Hy.jpg&quot; alt=&quot;outcrop&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13928" LastEditorUserId="81" LastEditDate="2023-09-07T13:39:59.887" LastActivityDate="2023-09-07T13:39:59.887" Title="Can a braided stream create thick relatively continuous siltstone beds?" Tags="|geology|sedimentology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18379" PostTypeId="2" ParentId="18376" CreationDate="2019-11-05T04:49:09.707" Score="2" Body="&lt;p&gt;Greenhouses can be built anywhere, so long as the plants within them are provided with sufficient nutrients and light. Depending on the crop, soil is not required if &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydroponics&quot; rel=&quot;nofollow noreferrer&quot;&gt;hydroponic&lt;/a&gt; methods are used.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The use of agricultural lands is not a requirement. In urban areas, disused warehouses and other buildings are used to establish &lt;a href=&quot;https://en.wikipedia.org/wiki/Vertical_farming&quot; rel=&quot;nofollow noreferrer&quot;&gt;vertical farms&lt;/a&gt;. Greenhouses are even placed on &lt;a href=&quot;https://myrooff.com/rooftop-greenhouse/&quot; rel=&quot;nofollow noreferrer&quot;&gt;roofs of buildings&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-11-05T04:49:09.707" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18380" PostTypeId="1" CreationDate="2019-11-05T05:28:36.830" Score="1" ViewCount="64" Body="&lt;p&gt;Very similar to what happens in other sciences, I would like to know, ¿What are the main hypotheses or postulates that are currently being reviewed and studied in Earth Sciences?&lt;/p&gt;&#xA;" OwnerUserId="8507" LastEditorUserId="8507" LastEditDate="2019-11-05T12:28:34.377" LastActivityDate="2019-11-05T12:28:34.377" Title="What are the main hypotheses or postulates that are currently being reviewed and studied in Earth Sciences?" Tags="|history-of-science|" AnswerCount="0" CommentCount="4" ClosedDate="2019-11-05T11:40:07.173" ContentLicense="CC BY-SA 4.0" />
  <row Id="18381" PostTypeId="2" ParentId="18378" CreationDate="2019-11-05T11:51:00.707" Score="-1" Body="&lt;p&gt;Braided channels are usually found in estuaries. Estuaries are usually on the coast. That being the case, it seems possible that now and again a high tide brought in some sand which covered the silt-filled channels, which then brought more silt, thus creating the layered structure you describe. If the site is now a long way from the coast, it doesn't follow that it always was.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-05T11:51:00.707" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18382" PostTypeId="1" CreationDate="2019-11-05T16:14:26.900" Score="1" ViewCount="166" Body="&lt;p&gt;Today, a student asked this question, and I was unable to answer it in a way that was understandable and accurate - even for myself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For seismic data acquisition projects, how are sensors able to 'hear' seismic signals in the midst of other much 'louder' and more ongoing ambient noise sources/events?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand that the spectral characteristics of ambient noise - be it a culmination of periodic and/or transient events - are usually much different than downgoing/upcoming recorded seismic signals (~15 - 100Hz). However, I'm unsure if the ability to 'see' through the noise at the &lt;em&gt;acquisition stage&lt;/em&gt; is more of a sensor specification topic than some pre-processing filtering/gain action occurring real-time during recording.&lt;/p&gt;&#xA;" OwnerUserId="8447" LastEditorUserId="8447" LastEditDate="2019-11-05T18:06:04.100" LastActivityDate="2019-11-05T18:06:04.100" Title="Hydrophone/geophone sensor sensitivity - noise versus signal" Tags="|geophysics|seismic|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18383" PostTypeId="1" CreationDate="2019-11-05T16:17:18.553" Score="2" ViewCount="102" Body="&lt;p&gt;The usual explanation for the Indian Monsoon that I read everywhere is that it is generated by winds from the Arabic Sea, moving to India mainland because of the low pressure there. These winds are stopped by the Himalayan mountains, the air rises and cools down, giving heavy rains. But if this is true I would expect rains starting next to the Himalayas, and then eventually travel south to complete a cycle. Why is the monsoon starting in the south instead? The Himalayas are clearly a barrier, and that's why in Tibet they don't experience the monsoon, but to me it doesn't make sense that they are the reason for the south-west monsoon, I would say more the Western Ghats.&lt;/p&gt;&#xA;" OwnerUserId="18218" LastActivityDate="2019-11-05T17:53:27.923" Title="Why the Indian Monsoon doesn't start in the north?" Tags="|meteorology|monsoon|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18384" PostTypeId="2" ParentId="18382" CreationDate="2019-11-05T17:02:45.523" Score="1" Body="&lt;p&gt;Sound-generating wave action takes place only on the surface, and is usually less noisy than seismic events. I'm not sure what you mean by streamers, but I take it you mean ships. These man made sounds are loudest on the surface and much quieter in the depths, whereas  with seismic noises it is the other way around, so the way to preferentially hear seismic sounds is to send your hydrophones deep. In any case, man made sounds are usually very transient and would not cause much interference. Shipping tends to stick to recognised routes, so you would place your hydrophones away from heavily used shipping lanes.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-05T17:02:45.523" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18385" PostTypeId="1" CreationDate="2019-11-05T17:21:23.147" Score="1" ViewCount="50" Body="&lt;p&gt;I have a indoor &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; monitor and putting it on my balcony it indicates values of 1400-2200 ppm for different days ? Is this even possible and what are the ranges of &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; levels for the outside air of larger inner cities ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also should &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; be added to the list of gasses measured by the air quality index ? I know it doesn't accurately measure the source that generates the &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;, but at least people should have a general idea of the levels of &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; in different areas so they can better pick a cleaner place to live in.&lt;/p&gt;&#xA;" OwnerUserId="18219" LastEditorUserId="2470" LastEditDate="2020-01-04T19:34:13.433" LastActivityDate="2020-01-04T19:34:13.433" Title="What are the ranges of CO2 levels for inner cities and should CO2 be added to the air quality index?" Tags="|climate-change|air-quality|urban-climate|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18386" PostTypeId="2" ParentId="18383" CreationDate="2019-11-05T17:53:27.923" Score="2" Body="&lt;p&gt;Summarizing what I wrote in the comments&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) The monsoon does not start off in the Arabian Sea. There is actually a cross equatorial gradient that drives winds from the Southern Indian Ocean into the Northern Indian Ocean and then into the Arabian Sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) There is also a second branch of the Indian monsoonal winds and that is the Bay of Bengal branch. This branch also receives winds from the Southern Indian Ocean. This branch ends up contributing easterlies and south easterlies to the Indian monsoon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3) The crucial aspect that you left out in the question is the role of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Monsoon_trough&quot; rel=&quot;nofollow noreferrer&quot;&gt;Monsoon trough&lt;/a&gt;. The monsoon is not just made of winds alone converging rather it is the north to south movement and sometimes south to north movement of the monsoon trough along the Indian subcontinent that researchers and forecasters track. Why is that ? It is because systems form within the monsoon trough. What governs the movement of the monsoon trough up and down the Indian subcontinent ? Well that is a topic beyond the scope of this question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;4) So the monsoon trough includes westerly winds in the equatorward section and in the poleward section you have trade winds. The Himalayan branch from that definition contains easterly winds and not westerly winds from the Arabian Sea.Actually Arabian Sea winds  only have a secondary role in providing moisture for systems to form in the Himalayan side.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;5) Finally the Indian Himalayas only receive rainfall when the monsoon trough is located along those latitudes. This condition is known as a &quot;break monsoon&quot; condition and it happens when sub tropical westerlies are present aloft. This usually happens after the monsoon has provided rain to the southern parts of the country including the western ghats.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would recommend going through this free e-book - &lt;a href=&quot;http://imdpune.gov.in/Weather/Reports/sw%20monsoon%20whole%20book.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;sw monsoon e-book&lt;/a&gt; for a thorough description of what I have mentioned above. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastActivityDate="2019-11-05T17:53:27.923" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18387" PostTypeId="1" AcceptedAnswerId="18389" CreationDate="2019-11-05T17:55:40.453" Score="1" ViewCount="145" Body="&lt;p&gt;I am a farmer. I have lot of &quot;touch me not&quot; plants (Mimosa pudica)in my coconut plantation field. Many people are saying I have to get rid of them for two reasons:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;It is very difficult to walk in the field for routine works.&lt;/li&gt;&#xA;&lt;li&gt;These plants consume nutrients from main crops. &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;I am bit reluctant to remove these plants. I understand that these plants help in &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{N_2}$&lt;/span&gt; fixation. Also these plants may protect my field from some of the animals I thought though it is inconvenient to walk.&#xA;So my main question is: Do these touch me not plants consume nutrients from the  fertilizer I put on coconut plants? Are there any ill effects of these plants?&lt;/p&gt;&#xA;" OwnerUserId="18220" LastEditorUserId="2470" LastEditDate="2020-01-04T19:33:02.433" LastActivityDate="2020-01-04T19:33:02.433" Title="Does nitrogen fixation plants consume nutrients from soil" Tags="|nitrogen|nutrient-cycles|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18389" PostTypeId="2" ParentId="18387" CreationDate="2019-11-05T18:50:50.593" Score="2" Body="&lt;p&gt;I'm not familiar with the plants you mention, unless they are the ones whose leaves rapidly move away from you when touched. I saw some in Malaya. However, the plants well known for fixing nitrogen from the air and enriching the soil are legumes, belonging to the same group as peas, beans, alfalfa and clover. There are hundreds of them, and they all have similarly shaped flowers, though of many different colours.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They all have nodules on their roots which harbour the bacteria which do the actual nitrogen fixation. Like any other plant they also extract minerals from the soil, so the soil will be enriched with nitrogen but depleted in minerals. Farmers get round this difficulty by rotation of crops.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the flowers of the plants you mention are similar in shape to the flowers of peas and beans they probably enrich the soil, and it is unlikely they remove enough minerals to harm your coconut palms. In England, farmers sometimes sow a legume like clover or alfalfa, then plough it back in so that the soil is enriched with nitrogen but not depleted in minerals. Perhaps you could do the same with your mimosa plants.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most fertilisers contain nitrogen, and if yours contains anything else your mimosa will probably use a bit of it, but not enough to worry about. If your plants are indeed a kind of legume, that should enable you to use less fertiliser. If your touch-me-not plants have thorns on them, that's the only ill effect I can think of.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-05T18:50:50.593" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18390" PostTypeId="1" CreationDate="2019-11-05T21:31:09.197" Score="40" ViewCount="13483" Body="&lt;p&gt;I think the level of carbon dioxide in the air is high enough to reduce the intelligence of humans. This has nothing to do with climate change.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Except that both mean we should reduce CO₂.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I never heard of that, surprisingly, but deducted that from simple known facts. I hope I'm missing something.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe my idea is just wrong? It's simple enough to explain here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Elevated CO₂ levels in office air reduce the cognitive ability of office workers, that is well established.&lt;br&gt;&#xA;That is measurable by experiment. Complaints about drowsiness start at about 1000 ppm CO₂ in air.&lt;br&gt;&#xA;Reduction in cognitive ability does happen with drowsiness, almost by definition.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The level of CO₂ is currently a significant fraction of 1000 ppm, about 409 ppm as of November 2019.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The CO₂ level in a typical western indoor working environment raises by multiple 100 ppm over the day, exhaled by people breathing in the working environment.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;With an increasing base level, an increasing level in workplace air reaches a fixed threshold sooner, because CO₂ levels are additive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The base level does increase. Therefore a level of CO₂ that reduce the cognitive ability of humans is reached earlier in a working day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the base level is higher, base level plus the additional CO₂ in office air  reach a level that reduces cognitive ability sooner during a work day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This happens globally in many workplaces.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is true for any values of base concentration, threshold concentration and maximum of increase during a day that are of the same order of magnitude. This estimation is optimistic, because it assumes that the effect has a sudden onset at a level that causes obvious symptoms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To summarize the central points: Some CO₂ concentration exists that has negative effects. An offset in base air concentration results in an offset in the workplace concentration. That means the detrimental concentration is reached more often. For this to be true, the exact numbers are not even relevant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ok, what's wrong with that deduction?&lt;br&gt;&#xA;I really hope there is something wrong.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this is a reason to care about the level of carbon dioxide in common air, it is completely independent of climate change, an alternative motivation to do exactly the same thing. That seems very relevant to me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://climate.nasa.gov/system/resources/detail_files/24_co2-graph-061219-768px.jpg&quot; alt=&quot;co2 levels&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="321" LastEditorUserId="321" LastEditDate="2019-11-26T09:53:29.700" LastActivityDate="2020-02-12T16:32:09.353" Title="CO₂ level is high enough that it reduces cognitive ability. Isn't that a reason to worry?" Tags="|climate-change|greenhouse-gases|" AnswerCount="7" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="18391" PostTypeId="2" ParentId="18390" CreationDate="2019-11-05T22:42:39.053" Score="2" Body="&lt;p&gt;You are being alarmist. &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; levels vary considerably from place to place, but as you know, the average level is just over 400 ppm. You have a higher level than that in your own lungs at this moment, so it is far too low to cause mental problems. Places with raised &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; levels have existed since time immemorial, but were rarely high enough to produce the cognitive deficiency you speak of. If raised &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; levels were significantly reducing the efficiency of their workforce, employers would soon find a way of piping fresh air to them. Perhaps opening the windows would be enough. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Carbon monoxide (CO) is far more of a danger than &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;, as it cuts off the supply of oxygen to the brain, and worldwide, thousands of people die of CO poisoning each year. It comes from the same sources that produce &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;, but where combustion is inefficient the &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; is mixed with carbon monoxide. &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; can become dangerous when levels increase beyond about 3 percent by volume, but this rarely happens. Humans can tolerate levels much higher than 400 ppm without ill effect.       &lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="2470" LastEditDate="2020-01-04T19:10:31.637" LastActivityDate="2020-01-04T19:10:31.637" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="18392" PostTypeId="2" ParentId="18390" CreationDate="2019-11-06T00:15:32.710" Score="40" Body="&lt;p&gt;There looks like legitimate cause &lt;em&gt;for further study&lt;/em&gt;, preferably by scientists breathing air under 950 ppm &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; (&lt;a href=&quot;https://ehp.niehs.nih.gov/doi/10.1289/ehp.1510037&quot; rel=&quot;nofollow noreferrer&quot;&gt;this study&lt;/a&gt; showing a 15% decline in cognitive ability at this level). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because it is not known what mechanisms are involved in this decline in cognitive ability it is not clear if there are threshold levels, with step changes in impacts or if the effect is linear, but changes at below 950 ppm is indicated and subtle impacts at much lower level seem likely, with one leading expert (&lt;a href=&quot;https://soa.cmu.edu/vivian-loftness&quot; rel=&quot;nofollow noreferrer&quot;&gt;Vivian Loftness&lt;/a&gt;) on Health, Productivity, and the Quality of the Built Environment suggesting atmospheric levels above 600 ppm would be cause for concern about cognitive effects. For people with poor cognitive abilities potential impacts of &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; levels is not known, but could be significant - this, along with impacts more generally at levels that are within the range of possible &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; concentrations people now living can expect outdoors needs more study.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The principle response in the near term is improving air quality in buildings, with raised atmospheric &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; levels most significant with respect to rates of &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; buildup and the required air replacement by ventilation systems. There are ample reasons to commit to actions that reduce emissions and &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; rise in the atmosphere, but better understanding of &lt;em&gt;all&lt;/em&gt; the potential consequences is worthwhile.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="2470" LastEditDate="2020-01-04T19:06:06.390" LastActivityDate="2020-01-04T19:06:06.390" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18394" PostTypeId="1" CreationDate="2019-11-06T12:00:57.350" Score="1" ViewCount="55" Body="&lt;p&gt;In 1982 ExxonMobil made this diagram with a slightly excess of the concentration of atmospheric carbon dioxide and global warming. Can this error be explained by the Russian industrial collapse in the 90's, when their oil and coal production was very low for some years?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.theguardian.com/environment/climate-consensus-97-per-cent/2018/sep/19/shell-and-exxons-secret-1980s-climate-change-warnings&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source: The Guardian&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/R6EyV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/R6EyV.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xiorP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xiorP.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="16809" LastEditorUserId="16809" LastEditDate="2019-11-06T12:48:17.140" LastActivityDate="2019-11-06T12:48:17.140" Title="The climate effect of the Russian industrial collapse in the early 90's" Tags="|climate-change|greenhouse-gases|fossil-fuel|predictability|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18397" PostTypeId="1" AcceptedAnswerId="18421" CreationDate="2019-11-06T14:44:07.937" Score="1" ViewCount="977" Body="&lt;p&gt;I am a statistician working on a climatological downscaling project in the Caribbean Sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am just starting to learn about the CMIP5 GCM data project. I plan to download CMIP5 data from 6 climate centers and examine 3 scenarios: historical, RCP4.5, and RCP8.5 I was hoping that someone could further explain the CMIP5 ensemble RIP-nomenclature to me:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;R: realization&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I: initialization&lt;/p&gt;&#xA;&#xA;&lt;p&gt;P: physics&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More specifically, if I were to use the same ensemble number (say r1i1p1) across all 6 centers - would I have the exact same data for each scenario (historical, RCP4.5, and RCP8.5)?  If not, should I keep the ensemble number consistent across models or should I vary it somewhat?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I guess the main question here: is it more common in geography to examine the variance between climate center projections or the variance between runs within a single ensemble?&lt;/p&gt;&#xA;" OwnerUserId="18232" LastActivityDate="2019-11-09T16:02:47.293" Title="How to better understand the RIP-nomenclature used in the CMIP5 project?" Tags="|meteorology|climate-change|climate|climate-models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18399" PostTypeId="2" ParentId="18390" CreationDate="2019-11-06T16:26:08.497" Score="2" Body="&lt;p&gt;Even if your concern is interesting the &quot;fact&quot; you bourght up seems surprinsing to me. With ventilation and open windows, it seems strange to me that &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; level increase that much but still, I'm no expert... So I checked.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;After a bit of research I found this &lt;a href=&quot;https://www.lesswrong.com/posts/DtQzYXBTwaWXbhCoS/stale-air-high-co2-may-decrease-your-cognitive-function&quot; rel=&quot;nofollow noreferrer&quot;&gt;article&lt;/a&gt; which talk about the 15% drop in cognitive function in office with 1000 ppm (which Michael Walsby bourght up in his answer) and a link to the study from where those data are from.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I went straight at the conclusion of &lt;a href=&quot;https://www.gwern.net/docs/co2/2015-stafford.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;said article&lt;/a&gt; and from what I read, it seems to be more about an increase in test score based on environment quality (mostly air quality and mold from what I read) and this make a big difference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The result could be because of an alarming &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; level that is corrected with a ventilation improvement, or it could just be because the air is easier to breath so student are less stressed out.&#xA;From what I see, the study only talk about a link between environment quality and performances at different tests. It does not conclude anything about &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; level, which means that the article which was talking about the 15% decrease in cognitive ability probably over-interpreted the article.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I haven't done more research but I think your concern is probably a wrong interpretation of some articles doing a wrong interpretation of studies that are too fiew to draw a clear conclusion.&#xA;It's still an interesting topic though but without more studies it's just speculation from what I see.&lt;/p&gt;&#xA;" OwnerUserId="18233" LastEditorUserId="2470" LastEditDate="2020-01-04T19:08:41.567" LastActivityDate="2020-01-04T19:08:41.567" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18402" PostTypeId="1" CreationDate="2019-11-06T17:54:42.757" Score="1" ViewCount="81" Body="&lt;p&gt;How do you construct a paleogeographic map with given sedimentary structures as guidelines?&lt;/p&gt;&#xA;" OwnerUserId="18236" LastEditorUserId="18236" LastEditDate="2019-11-09T12:32:01.240" LastActivityDate="2019-11-09T12:32:01.240" Title="Paleogeographic Map" Tags="|geology|paleogeography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18403" PostTypeId="2" ParentId="18402" CreationDate="2019-11-06T23:25:11.443" Score="1" Body="&lt;p&gt;While we're certainly not going to do your homework for you (and we couldn't anyway, because the map is not legible in the photo you provided), this looks like a fun exercise and a chance to express your creativity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your teacher has asked you to draw some paleo geographic features on a map given some sedimentary features that have been plotted for you. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Try to think of how those features are laid down in a sedimentary environment. Are they indicative of land? rivers? ocean?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, if there's a point that shows sandstone, there must have been sand laid down in the past. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then, picture how the features that your teacher wants would have contributed to that deposition, and where they would have been in relation to one another while the sediments were being deposited.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, you can draw the features on the map in between or around the provided points, based upon how you decided that would happen.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2019-11-06T23:31:36.547" LastActivityDate="2019-11-06T23:31:36.547" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18407" PostTypeId="2" ParentId="18390" CreationDate="2019-11-07T13:16:52.173" Score="-1" Body="&lt;p&gt;I don't doubt that CO&lt;sub&gt;2&lt;/sub&gt; has the potential to impact cognitive abilities and that poor air quality really affects many people. However, if we consider all factors impairing cognitive abilities in a typical office environment, the elephant in the room is the &lt;a href=&quot;https://psychology.stackexchange.com/a/24414/24666&quot;&gt;noise&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore I believe that the impact of CO&lt;sub&gt;2&lt;/sub&gt; on cognitive abilities doesn't hit the news because it's not as significant as other factors such as the noise. It only starts to be a problem half-way though the day if ventilation is inadequate, whereas noise becomes a problem for most people even before they arrive to work (loud noise has &lt;strong&gt;lasting&lt;/strong&gt; effect on the cognitive performance), and keeps being a problem the whole day.&lt;/p&gt;&#xA;" OwnerUserId="6715" LastEditorUserId="6715" LastEditDate="2019-11-08T10:20:21.993" LastActivityDate="2019-11-08T10:20:21.993" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="18409" PostTypeId="1" CreationDate="2019-11-07T20:31:55.403" Score="3" ViewCount="89" Body="&lt;p&gt;It is stated in &lt;a href=&quot;https://cdiac.ess-dive.lbl.gov/trends/co2/ice_core_co2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://cdiac.ess-dive.lbl.gov/trends/co2/ice_core_co2.html&lt;/a&gt; that the temporal uncertainty for the glacier &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; records is less than &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{5~\%}$&lt;/span&gt; at any given moment. That means ‒ for example ‒ ca. &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{5,\!000}$&lt;/span&gt; years at &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{100,\!000}$&lt;/span&gt; years ago.  Could there have been peaks in the &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; record that rose and fell back so quickly we wouldn't be able to detect them? Is there some paper or perhaps a monography that lists all the possible events in Earth's history that could have occurred in the last &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{800,\!000}$&lt;/span&gt; or more years, which would lead to a likewise fast &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; increase as today's, but also showing that, on the other hand, any such events would leave a long-lasting trace in the &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; that should be easily detectable in the record?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've found out that part of the answer is already in answers to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/18141/is-there-any-natural-phenomenon-that-can-account-for-the-100-fold-faster-co2-rat&quot;&gt;this question&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="18249" LastEditorUserId="2470" LastEditDate="2020-01-04T19:24:28.107" LastActivityDate="2020-01-04T19:25:27.267" Title="In the 800 kyr $\ce{CO_2}$ record, how detectable would a short-term peak be?" Tags="|climate-change|paleoclimatology|co2|literature-request|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18410" PostTypeId="1" CreationDate="2019-11-07T23:15:13.017" Score="1" ViewCount="79" Body="&lt;p&gt;A huge amount of &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; is absorbed by the ocean and stored in the ocean, and methane is stored as clathrates. For every mega-meteorite or asteroid that impacts on land, two hit the sea. In a range of sizes between Barringer and Chicxulub, how big would a mega-meteorite have to be to release climate changing amounts of &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; and methane from the sea? The multi-megaton fusion device that destroyed Elugulab Island in the Eniwetok atoll, Marshal Islands, in 1952 was considerably more powerful than the Barringer meteorite, but does not appear to have released significant amounts of greenhouse gases. Obviously a lot depends on where in the ocean the mega-meteorite lands, so let's say it lands in a place with higher than average quantities of &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; and methane.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="2470" LastEditDate="2020-01-04T19:26:46.123" LastActivityDate="2020-01-04T19:26:46.123" Title="Ocean Greenhouse Gases Released by Meteorite Impact" Tags="|meteorite|greenhouse-gases|methane|impacts|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18411" PostTypeId="2" ParentId="5018" CreationDate="2019-11-08T08:18:57.713" Score="0" Body="&lt;p&gt;Both carbon sinks and carbon reservoirs store carbon and accumulate them but the only difference is in their flexibility and stability to release carbon back to the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In simple terms, carbon sink (like iceberg) takes longer time to release carbon because it takes longer time to melt. On the other hand, in your example, the mature forests can release carbon relatively quicker because they are in their last stage of their life cycle and hence they are carbon reservoirs. &lt;/p&gt;&#xA;" OwnerUserId="18256" LastActivityDate="2019-11-08T08:18:57.713" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18413" PostTypeId="2" ParentId="18390" CreationDate="2019-11-08T15:18:18.083" Score="8" Body="&lt;p&gt;Two recent studies tend to contradict the 2016 study mentioned in Ken Fabian's answer.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pubmed/29789085/&quot; rel=&quot;noreferrer&quot;&gt;Acute Exposure to Low-to-Moderate Carbon Dioxide Levels and Submariner Decision Making&lt;/a&gt; (June 2018) reports:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;METHODS:&lt;/p&gt;&#xA;&lt;p&gt;Using a subject-blinded balanced design, 36 submarine-qualified sailors were randomly assigned to receive 1 of 3 &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; exposure conditions (600, 2500, or 15,000 ppm). After a 45-min atmospheric acclimation period, participants completed an 80-min computer-administered SMS test as a measure of decision making.&lt;/p&gt;&#xA;&lt;p&gt;RESULTS:&lt;/p&gt;&#xA;&lt;p&gt;There were no significant differences for any of the nine SMS measures of decision making between the &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; exposure conditions.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pubmed/31240239&quot; rel=&quot;noreferrer&quot;&gt;Effects of acute exposures to carbon dioxide on decision making and cognition in astronaut-like subjects&lt;/a&gt; &lt;em&gt;NPJ Microgravity&lt;/em&gt;. (June 2019) 5: 17, which shares an author with the 2016 study, finds:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oefxV.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oefxV.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="248" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-01-04T19:07:04.240" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18414" PostTypeId="1" CreationDate="2019-11-08T18:35:49.427" Score="1" ViewCount="4515" Body="&lt;p&gt;Why does the temperature of let’s say 85 degrees Fahrenheit in southern California feel hotter at 7,500 ft elevation than it does at sea level?&lt;/p&gt;&#xA;" OwnerUserId="18271" LastActivityDate="2019-11-08T19:58:03.620" Title="Heat at High Altitudes" Tags="|meteorology|atmosphere|geophysics|temperature|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18415" PostTypeId="2" ParentId="18409" CreationDate="2019-11-08T19:31:03.243" Score="2" Body="&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; does not fall back quickly:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;graph shows the IPCC 2007 &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; liftime from a computer model run that shows what happens to a single instantaneous pulse of &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; emitted to the atmosphere. One thousand years after the &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; is emitted to the atmosphere 20% is still there according to this model.&lt;br&gt;&#xA;  &lt;a href=&quot;http://www.onlyzerocarbon.org/carbon_dioxide.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;only zero carbon&lt;/a&gt;&#xA;  &lt;a href=&quot;https://i.stack.imgur.com/xGgoh.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xGgoh.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The decline shown is mostly due to &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; dissolving in the oceans.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="2470" LastEditDate="2020-01-04T19:25:27.267" LastActivityDate="2020-01-04T19:25:27.267" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18416" PostTypeId="2" ParentId="18414" CreationDate="2019-11-08T19:58:03.620" Score="2" Body="&lt;p&gt;How things feel is partly psychological and often doesn't have a purely physical explanation. If you run a hot bath and the water from the tap starts to feel tepid, plunge your hand into the very hot water with which the bath is filled. Hold it there for a minute or two, then put it under the tepid tap. The water will feel stone cold, though when tested with the other hand it still feels tepid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If 85F at 7,500 ft feels hotter to you than 85F at sea level, it could be due to a number of things. On a sunny day you will get more solar radiation at high altitude, especially around mid day, and that will be in addition to the shade temperature which weather forecasters use. When walking from A to B in the mountains, we usually exert ourselves more than we would at sea level, and therefore we feel hotter. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The day you have in mind might have been especially humid in your mountain location, so that would make it feel warmer as well. Maybe your walk was when the sun was at its highest and you are comparing it to walks in the lowlands where, although the shade temperature was the same, the sun was lower in the sky or maybe there was even some cloud. And always there is the psychological aspect to consider. Our minds like to play tricks on us.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-08T19:58:03.620" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18418" PostTypeId="1" AcceptedAnswerId="18420" CreationDate="2019-11-09T00:23:51.023" Score="2" ViewCount="88" Body="&lt;p&gt;How are ore body sizes determined? What are the most reliable techniques of determining the size of ore deposits as well as their content?&lt;/p&gt;&#xA;" OwnerUserId="18274" LastActivityDate="2019-11-09T10:39:57.737" Title="Ore Deposit Determination" Tags="|mineralogy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18419" PostTypeId="1" CreationDate="2019-11-09T03:00:00.680" Score="1" ViewCount="56" Body="&lt;p&gt;I'm looking into growing edible oyster mushrooms. I'm considering using whole-oat horse feed in the growing process. I realize that additional steps are taken to ensure food is fit for human consumption, but for my purposes, I'd be fine with having a few dead bugs in the mix. However, I am wondering if there could be additional chemicals in horse oats over human oats. In the USA, are pesticides regulated differently for animal vs human consumption? Anything else I should be concerned about?&lt;/p&gt;&#xA;" OwnerUserId="18277" LastActivityDate="2019-11-10T10:56:24.283" Title="In the USA, are pesticides regulated differently for animal vs human consumption?" Tags="|agriculture|united-states|" AnswerCount="1" CommentCount="2" ClosedDate="2019-11-14T12:53:30.837" ContentLicense="CC BY-SA 4.0" />
  <row Id="18420" PostTypeId="2" ParentId="18418" CreationDate="2019-11-09T05:30:35.173" Score="2" Body="&lt;p&gt;The initial stage of mineral exploration involves finding a site to investigate. In some situations this may result from the discovery of a &lt;a href=&quot;https://www.911metallurgist.com/blog/mineral-surface-outcrops&quot; rel=&quot;nofollow noreferrer&quot;&gt;surface outcrop of mineralization&lt;/a&gt;, which is the exposure of a mineral deposit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Surface outcrops are becoming more difficult to find because some have already been mined or they are buried under sediments or lava flows. To get an indication where buried mineral deposits occur, &lt;a href=&quot;https://en.wikipedia.org/wiki/Exploration_geophysics&quot; rel=&quot;nofollow noreferrer&quot;&gt;geophysical exploration techniques&lt;/a&gt; are required. Generally this will require the use of either gravity measurements and/or magnetic surveys, usually aeromagnatic surveys. In some situations &lt;a href=&quot;https://en.wikipedia.org/wiki/Geochemistry&quot; rel=&quot;nofollow noreferrer&quot;&gt;geochemical&lt;/a&gt; exploration methods may be used as well. This requires wandering over land taking samples of the surface rocks and &lt;a href=&quot;https://en.wikipedia.org/wiki/Metallurgical_assay&quot; rel=&quot;nofollow noreferrer&quot;&gt;assaying&lt;/a&gt; them for minerals and metals. The assaying method used will be determined by the metal being explored for. Fire assays, when they are used, are used for gold, not &lt;a href=&quot;https://en.wikipedia.org/wiki/Base_metal&quot; rel=&quot;nofollow noreferrer&quot;&gt;base metals&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When a prospective area has been found, exploration drilling is undertaken. Initially reverse circulation drilling may be done because it is cheaper and quicker. The cuttings from the drill holes are analyzed by a geologist to ascertain the rock types and samples of prospective rock types are assayed for their metal content.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the mineral deposit is large enough and rich enough, &lt;a href=&quot;https://en.wikipedia.org/wiki/Exploration_diamond_drilling&quot; rel=&quot;nofollow noreferrer&quot;&gt;diamond drilling&lt;/a&gt; will be undertaken. Depending on the condition of the ground being drill, this generally provides a solid core of rock that can be inspected for rock type. Usually the core is split in half lengthwise and half the core for prospective rock types are assayed for metal content.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get an accurate understanding of the size the mineral deposit and the amount of metal present. A grid of holes, drilled on a 20 m by 20 m or a 10 m by 10 m pattern is drilled over the deposit. The length of the drill holes will largely be determined by the depth of the mineral deposit. The results of this, outlines the size of the deposit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The assays for metal content and subsequent &lt;a href=&quot;https://en.wikipedia.org/wiki/Geologic_modelling&quot; rel=&quot;nofollow noreferrer&quot;&gt;modelling by geologists&lt;/a&gt; determines the amount of metal in the deposit (its richness). This may involve the use of &lt;a href=&quot;https://en.wikipedia.org/wiki/Geostatistics&quot; rel=&quot;nofollow noreferrer&quot;&gt;geostatistics&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Classifying the deposit as either a mineral deposit or orebody is done by mining engineers who evaluate the models created by the geologists by creating possible mine designs and evaluating the economics of the potential mine. If the deposit is economic to mine is called an orebody, if not it remains as a mineral deposit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As part of the mine design and evaluation process, the mining engineers must engage with metallurgists regarding how any ore from the deposit will be processed and the costs involved. In developed countries they must also consider the rehabilitation of any potential mine, once it has been mine out, during the evaluation of the mineral deposit.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2019-11-09T10:39:57.737" LastActivityDate="2019-11-09T10:39:57.737" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18421" PostTypeId="2" ParentId="18397" CreationDate="2019-11-09T16:02:47.293" Score="2" Body="&lt;p&gt;The RIP-nomenclature is used to distinguish between different runs of the same scenario &lt;em&gt;within&lt;/em&gt; a modeling center rather than to indicate any similarity &lt;em&gt;across&lt;/em&gt; modeling centers.  Strictly it's within and across models not centers, because some centers have more than one model, e.g., the MIROC center submitted models MIROC5, MIROC4h, MIROC-ESM, etc.  So r1i1p1 for some scenario is typically just the ensemble member that happened to be run first for each model.  One caveat is that whichever historial ensemble member you pick for each model, you should use the same member from the corresponding RCP scenario, e.g., historical r3i1p1 should join seamlessly with rcp8.5 r3i1p1:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A  recommendation  for  CMIP5  is  that  each  so-called  RCP  (future  scenario)  simulation  should when  possible  be  assigned  the  same  realization  integer  as  the  historical  run  from  which  it  was initiated. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;From Taylor et al (2012) &lt;em&gt;CMIP5 Data Reference Syntax (DRS) and Controlled Vocabularies&lt;/em&gt; (&lt;a href=&quot;https://pcmdi.llnl.gov/mips/cmip5/docs/cmip5_data_reference_syntax.pdf?id=3&quot; rel=&quot;nofollow noreferrer&quot;&gt;pdf&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There's loads more detail in that Data Reference Syntax doc that I've linked to, and a summary of it &lt;a href=&quot;https://pmip4.lsce.ipsl.fr/doku.php/database:drs&quot; rel=&quot;nofollow noreferrer&quot;&gt;on the IPSL website&lt;/a&gt;.  Karl Taylor gave a presentation that summarised it even more succinctly:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;r = “realization”: simulations started from equally likely initial conditions&#xA;  that lead to equally likely realizations of the true climate trajectory&lt;/li&gt;&#xA;  &lt;li&gt;i = “initialization”: only used in decadal predictions, to distinguish among&#xA;  different initialization procedures&lt;/li&gt;&#xA;  &lt;li&gt;p = “physics”: to identify simulations that are very closely related (e.g.,&#xA;  “perturbed physics” ensemble members or simulations forced by slightly&#xA;  modified parameterizations)&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In practice, the &quot;initialization&quot; and &quot;physics&quot; ensemble members are a bit specialist and the vast majority of CMIP5 users just stick to the rNi1p1 members, and most of them probably just stick to r1i1p1 from each model (e.g, &lt;a href=&quot;https://doi.org/10.1007/s00382-019-05014-6&quot; rel=&quot;nofollow noreferrer&quot;&gt;Peng et al, 2019&lt;/a&gt;) for simplicity.  You should feel free to use any of the &quot;realisation&quot; members from each model, and you could pick r1i1p1 from one model and r10i1p1 from another.  I'd advise sticking to one ensemble member from each model though, to avoid your analysis over-representing the forced responses of models that submitted more realizations to the CMIP5 database.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To address your final question, it's more common to look at the variance across the models for a given scenario.  But there are also plenty of studies that use the variance within each model ensemble to estimate the uncertainty of a model property due to internal variability, e.g., &lt;a href=&quot;https://www.nature.com/articles/s41561-019-0463-y&quot; rel=&quot;nofollow noreferrer&quot;&gt;emergent constraints on climate sensitivity&lt;/a&gt;.  It really depends what you're investigating.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2019-11-09T16:02:47.293" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18422" PostTypeId="1" AcceptedAnswerId="18462" CreationDate="2019-11-09T16:53:09.057" Score="2" ViewCount="515" Body="&lt;p&gt;I'm always hearing about tectonic plates as large chunks of crust floating on the mantle just like boats. In timescales of millions of years they move and even collide.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I'm starting to think this is just a pop-science model, or a methaphor, for a much more complex situation. I didn't made the calculation but I feel that the mass of the Indian plate is not as large to account for the uplifting of the Himalayas just by kinetic energy transfer. At those speeds (puny, even if large compared to other plate movements) wouldn't the material stress of the Eurasian plate had absorbed all the momentum by now? I get that the inertia of India is huge, but is it really as much as to keep pushing even today? Does it has so much inertia that it is still slowing down as it pushes Eurasia? I feel like there is a constant force been applied tangentially to the surface of the plate that could account for this instead of just a freely moving plate smashing another like two icebergs in the artic sea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does the idea of plates floating like boats and the idea of them interacting by mechanical collisions is really somehting more than a suggestive way of viewing a process that takes enourmous amounts of time, energy and mass so that we, insignificant and ephimeral creatures, can have a toy model in our minds? Is India been pushed by a force or is it really just moving like a billiard ball until it collides with another and changes its momentum?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT:&lt;/strong&gt;&#xA;Ok, so I've actually done the calculation now:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://pubs.usgs.gov/gip/dynamic/himalaya.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;According to the USGS&lt;/a&gt;, the Indian plate had a speed of &lt;span class=&quot;math-container&quot;&gt;$v =9 \; m/century = 2.85\cdot 10 ^{-9}\; m/s$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.thoughtco.com/sizes-of-tectonic-or-lithospheric-plates-4090143&quot; rel=&quot;nofollow noreferrer&quot;&gt;surface area of the plate&lt;/a&gt; is &lt;span class=&quot;math-container&quot;&gt;$A = 1.19\cdot 10^{7}\; km^2$&lt;/span&gt;. If we suppose the thickness of the crust here to be of &lt;span class=&quot;math-container&quot;&gt;$h = 50\; km$&lt;/span&gt; (which is thicker than it probably is) then the volume of the plate is &lt;span class=&quot;math-container&quot;&gt;$V = A\cdot h= 5.95\cdot 10^{8}\; km^3 = 5.95\cdot 10^{17}\; m^3$&lt;/span&gt;. We can estimate the mass of the plate by assuming a density of &lt;span class=&quot;math-container&quot;&gt;$\rho = 3\; g/cm^3 = 3\cdot 10^3\; kg/m^3$&lt;/span&gt; (this density is higher than the average we should expect for the crust so &lt;a href=&quot;https://en.wikipedia.org/wiki/Continental_crust&quot; rel=&quot;nofollow noreferrer&quot;&gt;we are not been very conservative at all&lt;/a&gt;). Thus the mass of the Indian plate is around &lt;span class=&quot;math-container&quot;&gt;$m = \rho V = 1.79\cdot 10^{21}\; kg$&lt;/span&gt; in the best case scenario.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then the kinetic energy of the Indian plate had to be lower than &lt;span class=&quot;math-container&quot;&gt;$E_k = \frac{1}{2}mv^2 = 7269\; J = 1.7 \; cal$&lt;/span&gt;, which is even less than what @Keith McClary has suggested since this is less than a &lt;span class=&quot;math-container&quot;&gt;$1/300 \; th$&lt;/span&gt; of the energy of a candy bar.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, we can use Newton's Second Law of Motion in the form &lt;span class=&quot;math-container&quot;&gt;$\Delta t = mv/F$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt; is the mass of the Indian plate and &lt;span class=&quot;math-container&quot;&gt;$v$&lt;/span&gt; is its velocity, to get the time needed to stop the plate, &lt;span class=&quot;math-container&quot;&gt;$\Delta t$&lt;/span&gt;, when we apply a constant force, &lt;span class=&quot;math-container&quot;&gt;$F$&lt;/span&gt;, against its motion. Even if the kinetic energy is insignificant it is not easily absorbed during a collision due to the huge inertia of the plate. But still if we suppose &lt;span class=&quot;math-container&quot;&gt;$1$&lt;/span&gt; million people, each person pushing with &lt;span class=&quot;math-container&quot;&gt;$3000 \; N$&lt;/span&gt; of force then those people could have stopped the continent in less than &lt;span class=&quot;math-container&quot;&gt;$\Delta t = 30\; minutes$&lt;/span&gt;. A &lt;a href=&quot;https://en.wikipedia.org/wiki/Orders_of_magnitude_(force)&quot; rel=&quot;nofollow noreferrer&quot;&gt;single weight-lifter&lt;/a&gt; would have been able to stop the entire Indian continental plate if he pushed with &lt;span class=&quot;math-container&quot;&gt;$F = 8000\; N$&lt;/span&gt; for about &lt;span class=&quot;math-container&quot;&gt;$\Delta t = 20.2\; years$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think that the mechanical stress of the entire eurasian continent creates larger forces that a single human and this &quot;collision&quot; has been going on for millions of years (not 20 years) and is still going on. So this is where it looks absurd to me to talk about a &quot;collision&quot; of plates for the formation of the Himalayas. The driving mechanism has to be a huge force pressing the Indian plate against Eurasia.&lt;/p&gt;&#xA;" OwnerUserId="18279" LastEditorUserId="18279" LastEditDate="2019-11-09T21:35:35.303" LastActivityDate="2019-11-15T04:44:15.980" Title="Do tectonic plates &quot;float&quot; over the mantle and &quot;collide&quot; like icebergs?" Tags="|plate-tectonics|models|crust|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18423" PostTypeId="2" ParentId="18422" CreationDate="2019-11-09T17:41:45.497" Score="0" Body="&lt;p&gt;Both mechanisms are at work. Continental crust is lighter than oceanic crust and lighter than mantle material, therefore it floats. But in addition to that, the very mantle forces that caused the plate to break off from a larger plate are still operating. The usual cause of a continental rift developing, as may be seen in East Africa's rift valley, are gigantic mantle plumes of hot magma rising from far below, and these continue to supply motive power long after a rift develops.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Indian plate, though moving at only a few centimetres per year, has enormous mass and therefore enormous kinetic energy. In addition to that, the mantle forces which broke it off from the Australian plate are pushing it north. It is likely getting some additional impetus from the adjacent African plate. The iceberg model therefore has some validity, but is not the whole story.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-09T17:41:45.497" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18424" PostTypeId="1" AcceptedAnswerId="18671" CreationDate="2019-11-09T17:46:05.993" Score="2" ViewCount="120" Body="&lt;p&gt;Would Large Igneous Provinces like the Deccan Traps have looked like ancient lunar Mare from space? Glowing lava oceans shinning in the night?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are these two things similar in nature? Would smoke from these regions fill the atmosphere with a haze that would hide the view from space?&lt;/p&gt;&#xA;" OwnerUserId="18279" LastActivityDate="2019-12-11T13:37:07.400" Title="Large Igneous Provinces are like Lunar Mare?" Tags="|volcanology|igneous|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18425" PostTypeId="2" ParentId="18424" CreationDate="2019-11-09T18:25:47.030" Score="0" Body="&lt;p&gt;Yes, there would have been seas of lava glowing in the night, but not as large as the lunar mare. The lunar mare were caused by asteroids punching through the then thin lunar crust and releasing a flood of magma from  below, as well as producing some magma of their own from the heat of impact. There is no evidence of anything of that nature causing the Deccan Traps or the Siberian Traps. There must have been some smoke and haze from both super-eruptions, but not enough to hide them from an observer in space in the unlikely event that there were any. Much of the incinerated trees and other vegetation were covered by sheets of lava, and therefore could not release much smoke and fumes.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-09T18:25:47.030" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18426" PostTypeId="2" ParentId="7892" CreationDate="2019-11-09T21:24:00.810" Score="1" Body="&lt;p&gt;Because there are only three types of rock; namely sedimentary, igneous and metamorphic, all rock materials we observe must fall into one of these categories. For example, when a planet is forming, the process by which dust accumulates through gravitational accretion must be considered sedimentary. Eventually, this material will be compressed and may become igneous as the gravitational pressure increases, but they are indeed sedimentary layers of dust and larger particulate matter. This material is not igneous, until it reaches sufficient temperatures to melt, and is not metamorphic until an outside force is applied to cause deformation of the stratified layers.  &lt;/p&gt;&#xA;" OwnerUserId="18280" LastActivityDate="2019-11-09T21:24:00.810" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18427" PostTypeId="1" AcceptedAnswerId="18439" CreationDate="2019-11-10T04:53:41.237" Score="9" ViewCount="841" Body="&lt;p&gt;This question assumes the accuracy of this (and similar) charts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KtJGU.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KtJGU.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://nas-sites.org/americasclimatechoices/more-resources-on-climate-change/climate-change-lines-of-evidence-booklet/evidence-impacts-and-choices-figure-gallery/figure-14/&quot; rel=&quot;noreferrer&quot;&gt;Source of image&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the image, CO&lt;sub&gt;2&lt;/sub&gt; peaked at about 260, perhaps 265 ppm during the interglacial periods between 800,000 years ago to the interglacial which ended about 480,000 years ago.    Beginning around 400,000 years ago, CO&lt;sub&gt;2&lt;/sub&gt; ppm reached about 280 ppm and repeated or exceeded that peak during the next 4 inter-glacial periods.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand that CO&lt;sub&gt;2&lt;/sub&gt; can play a feedback role, where as the oceans warm, less CO&lt;sub&gt;2&lt;/sub&gt; is absorbed and that can lead to higher CO&lt;sub&gt;2&lt;/sub&gt; ppm in the atmosphere, but whether the question is focused on the CO&lt;sub&gt;2&lt;/sub&gt; ppm or ocean temperatures, it's basically the same.   What was the cause for lower peak temperature and/or lower ocean temperature leading to lower peak CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere during that time period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles#Present_and_future_conditions&quot; rel=&quot;noreferrer&quot;&gt;Northern Hemisphere insolation&lt;/a&gt; doesn't explain it.   That underwent even wilder swings during the lower peak CO&lt;sub&gt;2&lt;/sub&gt; period.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="725" LastEditDate="2019-11-11T10:45:47.537" LastActivityDate="2019-12-15T01:52:05.630" Title="What caused peak CO2 to rise, starting about 400,000 years ago?" Tags="|climate-change|climate|climate-models|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18428" PostTypeId="1" CreationDate="2019-11-10T10:16:48.687" Score="1" ViewCount="37" Body="&lt;p&gt;I live in Iran and I want to do personal mineral prospecting for natural crystals and gemstones and beautiful minerals. Unfortunately, there are no &#xA;reliable information available. Anyone can help me where to start and any information about interesting site/spots?&lt;/p&gt;&#xA;" OwnerUserId="18282" LastActivityDate="2019-11-10T10:16:48.687" Title="mineral prospecting in Iran" Tags="|mineralogy|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18429" PostTypeId="2" ParentId="18427" CreationDate="2019-11-10T10:25:11.143" Score="-2" Body="&lt;p&gt;Prof Malte Jansen and his team at Chicago University have found that when the sea ice surrounding Antarctica increases, it cuts off the supply of CO2 from sea to air, which would explain the lows. When the sea ice retreats, that might explain the highs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You will immediately be thinking that the normal course of events is that CO2 moves from air to sea, so why should things be different in Antarctica? The Southern Ocean is extremely deep and cold. Deep, cold water holds more CO2 than shallow warmer waters. In the area surrounding Antarctica there are rising currents from vast depths, laden with CO2. Normally when these currents reach the surface, they deliver some of their excess CO2 to the atmosphere, then dive back down into the abyss where hydrothermal vents replace the CO2. When the surface is covered with ice, this gas delivery is halted, so atmospheric CO2 is reduced. Conversely, when the sea ice recedes the delivery of CO2 resumes, perhaps at an accelerated pace because of the build up of CO2 when deliveries were halted.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This mechanism could explain or partly explain the highs and lows on your chart, but does not exclude the possibility there may be other mechanisms at work as well. Prof Jansen is convinced that the scenario set out above explains ice ages and why they do not always fit comfortably with the Milankovitch Cycles. Obviously the increased albedo of advancing ice cover is another factor which helps to bring on an ice age.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-10T10:25:11.143" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18430" PostTypeId="2" ParentId="18419" CreationDate="2019-11-10T10:56:24.283" Score="1" Body="&lt;p&gt;I'm not familiar with pesticide legislation in the United States, but I do know that all oats are grown with human consumption in mind. Only the lower grades are used for animal feed. In the rare event that high grade oats become contaminated with insect pests, they would also be consigned to animal feed. Animals are less fastidious than humans, and don't mind a few beetles in their oats. It is highly improbable that your animal feed would be contaminated with pesticides, except to the extent that all non-organic farm produce has minute traces of it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most mushroom growers in UK use horse manure or stable muck as a substrate for growing their crop. The manure has to be suitably matured and not fresh. I would imagine it is cheaper than animal grade oats.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-10T10:56:24.283" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18431" PostTypeId="1" CreationDate="2019-11-10T19:18:30.787" Score="1" ViewCount="100" Body="&lt;p&gt;I live in a town that has a sizable pond that is dammed with a concrete overfall spillway. Decades ago the state demanded that the dam be installed to guarantee that the surface height of the pond remain the same when a culvert was being built at the outfall of the pond.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a problem because the pond is slowly silting up, and as it silts up it is becoming larger and larger and shallower and shallower, basically it is slowly turning into a marsh which is infiltrating into people's backyards (not mine, but those of some neighbors).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can this problem be solved?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2019-11-11T06:46:07.697" Title="How to deal with a pond silting up" Tags="|lakes|dams|" AnswerCount="3" CommentCount="3" FavoriteCount="0" ClosedDate="2019-11-11T14:00:13.740" ContentLicense="CC BY-SA 4.0" />
  <row Id="18432" PostTypeId="2" ParentId="18431" CreationDate="2019-11-10T21:19:43.910" Score="1" Body="&lt;p&gt;That is what lakes and ponds do , fill with silt. Serious earth moving equipment is needed to slow Mother Nature. Our community has recently removed some silt with draglines, bulldozers , trucks , etc. I don't know the cost but certainly significant . They concentrated on certain areas to facilitate flow as we have a dammed stream that made roughly a 300 and 100 acre lake and the costs of general silt removal would be overwhelming.  On the upside , bushes on a new island have become a egret rookery,&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2019-11-10T21:19:43.910" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18433" PostTypeId="2" ParentId="18431" CreationDate="2019-11-10T21:35:57.207" Score="1" Body="&lt;p&gt;Cut a notch into the dam so the water drains to the level you want. The marsh will shrink to a smaller size.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2019-11-10T21:35:57.207" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18435" PostTypeId="2" ParentId="18183" CreationDate="2019-11-11T02:50:17.347" Score="2" Body="&lt;p&gt;You can build a &lt;a href=&quot;https://www.linkedin.com/pulse/weather-forecasting-using-machine-learning-models-model-kinjal-ami&quot; rel=&quot;nofollow noreferrer&quot;&gt;machine learning algorithm&lt;/a&gt; with skill but you will need several parameters such as day of year, time of day, cloud cover, wind speed, and precipitation.  However, keep in mind that your algorithm will need to be trained on several years of previous data.  For projects like this, you typically want about 5 years of &lt;a href=&quot;https://stackabuse.com/using-machine-learning-to-predict-the-weather-part-1/&quot; rel=&quot;nofollow noreferrer&quot;&gt;observations&lt;/a&gt; to &quot;&lt;a href=&quot;https://getd.libs.uga.edu/pdfs/sanders_william_s_201712_ms.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;train&lt;/a&gt;&quot; the algorithm.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2019-11-11T03:30:53.210" LastActivityDate="2019-11-11T03:30:53.210" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18436" PostTypeId="2" ParentId="8806" CreationDate="2019-11-11T03:53:20.367" Score="0" Body="&lt;p&gt;There is a saltwater River in India called Luni river&#xA;Luni (also known as Lonari, Lavanavari, Lavanavati, Salt river) is a river in Rajasthan. It originates in the Pushkar valley of the Aravalli Range, near Ajmer, passes through the southeastern portion of the Thar Desert, and ends in the marshy lands of Rann of Kutch in Gujarat, after travelling a distance of 495 km.&lt;/p&gt;&#xA;" OwnerUserId="18285" LastActivityDate="2019-11-11T03:53:20.367" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18437" PostTypeId="2" ParentId="18431" CreationDate="2019-11-11T06:46:07.697" Score="1" Body="&lt;p&gt;Obviously removing the silt will increase the erosion along the banks of the pond(the neighbors will probably not like this).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It sounds to me like this pond is badly constructed if the erosion is eating away peoples property.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;the best option might be to fill in the area and use it for something else,a park-playground or simply let it become a wetland with wildlife.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastActivityDate="2019-11-11T06:46:07.697" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18438" PostTypeId="1" CreationDate="2019-11-11T06:47:22.770" Score="1" ViewCount="473" Body="&lt;p&gt;I live in Melbourne near a bay, and it always seems really dirty, whenever I go out to the open ocean the water always seems much cleaner. Is there a reason for this, does the bay trap pollution or do the waves from the ocean break up the pollution or does the ocean simply have more area to store waste? &lt;/p&gt;&#xA;" OwnerUserId="11725" LastEditorUserId="2470" LastEditDate="2019-11-11T17:57:26.177" LastActivityDate="2019-11-11T17:57:26.177" Title="Why does the ocean seem much cleaner than the bay I live near" Tags="|oceanography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18439" PostTypeId="2" ParentId="18427" CreationDate="2019-11-11T06:54:53.190" Score="11" Body="&lt;p&gt;First things first: There's nothing &lt;em&gt;per se&lt;/em&gt; wrong in science with answering &quot;We don't know&quot; to a vexing problem. This might well be one of those cases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question you are asking was asked by &lt;a href=&quot;https://science.sciencemag.org/content/207/4434/943&quot; rel=&quot;nofollow noreferrer&quot;&gt;Imbrie and Imbrie&lt;/a&gt; in 1980. The problem you have noticed (a very strong interglacial despite low Milankovitch forcing) is now known as the &quot;stage 11 problem&quot;, and this appears to be closely associated with the transition from a ~41000 year glacial cycle to the ~100000 year cycle we have seen for the last 900000 years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why &quot;stage 11&quot;? This is a reference to the concept of Marine Isotope Stages, depicted below. The Marine Isotope Stages refer to the abundance of oxygen 18 relative to oxygen 16. Water made of two protons (hydrogen) and one oxygen 16 atom evaporate more readily than does the slightly heavier water centered on an oxygen 18 atom. This makes the oxygen 18 levels in oceanic deposits a very nice proxy for climate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/F33y7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/F33y7.jpg&quot; alt=&quot;Graph of Marine Isotope Stages over the last million years&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sub&gt;Source: &lt;a href=&quot;https://skepticalscience.com/print.php?n=1703&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://skepticalscience.com/print.php?n=1703&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Three key transitions can be seen in the above graph. The glacial cycle started to change from a ~41000 year period to a ~100000 year period a bit less than one million years ago. The second transition occurred after MIS 17 when glacials shifted to being more extreme. The third transition, the one that you noticed, occurred after MIS 12 when interglacials shifted to being more extreme. This latter shift is the core of the &quot;stage 11 problem&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The key issue with explaining the observed ~100000 year cycle is that the Milankovitch forcings for a 100000 cycle are rather low while the Milankovitch forcings for a ~41000 year cycle are very strong. The stage 11 problem gets at the very heart of the 100000 problem because stages 12 and 11, which mark an extremely large swing in climate, occurred when Milankovitch forcings were very low. One non-solution of this stage 11 problem is that the onset of stage 11 (or possibly the onset of the preceding stage 12) represents when the 100000 year cycle finally took full control. This is essentially the argument made by &lt;a href=&quot;https://www.researchgate.net/profile/Gerold_Wefer2/publication/259278408_On_the_Dynamics_of_The_Ice_Ages_Stage-11_Paradox_Mid-Brunhes_Climate_Shift_and_100-Ky_Cycle/links/56dea9ef08aeb8b66f95f373/On-the-Dynamics-of-The-Ice-Ages-Stage-11-Paradox-Mid-Brunhes-Climate-Shift-and-100-Ky-Cycle.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Berger and Wefer&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, rhetorically, what &lt;em&gt;did&lt;/em&gt; cause this shift from a glacial cycle of ~41000 years to ~100000 years, and why did it take half a million years for this transition to become complete? A partial explanation by &lt;a href=&quot;https://www.nature.com/articles/nature12374&quot; rel=&quot;nofollow noreferrer&quot;&gt;Abe-Ouchi et al.&lt;/a&gt; is that something happened between 0.4 and 1.0 million years ago that enabled hysteresis loops. Instead of disappearing on a 41000 cycle, ice instead built up to such thick levels that all of the ice didn't melt at what would have ended a 41000 year glaciation. Once that happened, it wasn't much of a jump to survive two 41000 year cycles. But by then the ice had become so very thick that all that was needed was a mild forcing from warming to make the ice melt catastrophically.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This still falls in the &quot;and then magic happens&quot; category. One very plausible hypothesis that has gainied a lot of traction (e.g., &lt;a href=&quot;https://www.nature.com/articles/nature07158&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bintanja and Van de Wal&lt;/a&gt;) is that those massive ice sheets eventually pushed the built-up regolith from the 200+ million years since the previous ice age (the Karoo) either out to sea in the north or in huge piles of glacial drift to the south.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The initial glaciation events of the current ice age that started about 2.6 million years ago were rather weak in part because regolith makes for a rather nice ice lubricant. Those comparatively weak glaciation events continued for the next 1.6 million years, at a 41000 year interval. Much of the regolith had been pushed out of the way by a million years ago. While regolith is slippery (to ice), bare rock is anything but. This stickiness enabled ice to build up to the extent that those hysteresis loops could start to form, sporadically. It took another half a million years for the transition from a purely Milankovitch-driven 41000 year cycle to a Milankovitch+hysteresis 100000 year cycle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;&lt;strong&gt;References&lt;/strong&gt;:&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://science.sciencemag.org/content/207/4434/943&quot; rel=&quot;nofollow noreferrer&quot;&gt;Imbrie, John, and John Z. Imbrie&lt;/a&gt;. &quot;Modeling the climatic response to orbital variations.&quot; Science 207, no. 4434 (1980): 943-953.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.researchgate.net/profile/Gerold_Wefer2/publication/259278408_On_the_Dynamics_of_The_Ice_Ages_Stage-11_Paradox_Mid-Brunhes_Climate_Shift_and_100-Ky_Cycle/links/56dea9ef08aeb8b66f95f373/On-the-Dynamics-of-The-Ice-Ages-Stage-11-Paradox-Mid-Brunhes-Climate-Shift-and-100-Ky-Cycle.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Berger, W. H., and G. Wefer&lt;/a&gt;. &quot;On the dynamics of the ice ages: stage-11 paradox, mid-Brunhes climate shift, and 100-ky cycle.&quot; GEOPHYSICAL MONOGRAPH-AMERICAN GEOPHYSICAL UNION 137 (2003): 41-60.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/nature12374&quot; rel=&quot;nofollow noreferrer&quot;&gt;Abe-Ouchi, Ayako, Fuyuki Saito, Kenji Kawamura, Maureen E. Raymo, Jun’ichi Okuno, Kunio Takahashi, and Heinz Blatter&lt;/a&gt;. &quot;Insolation-driven 100,000-year glacial cycles and hysteresis of ice-sheet volume.&quot; Nature 500, no. 7461 (2013): 190.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/nature07158&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bintanja, R., and R. S. W. Van de Wal&lt;/a&gt;. &quot;North American ice-sheet dynamics and the onset of 100,000-year glacial cycles.&quot; Nature 454, no. 7206 (2008): 869.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="5282" LastEditDate="2019-12-08T13:15:30.730" LastActivityDate="2019-12-08T13:15:30.730" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18440" PostTypeId="2" ParentId="18438" CreationDate="2019-11-11T09:15:08.820" Score="2" Body="&lt;p&gt;I had the same experience when I lived in Cardiff, South Wales. When I lived there, the waters around Cardiff were always greyish and uninviting, but the further away one got, the more blue-green and transparent the sea became. Fifty miles west on the Gower coast, the water was pristine and beautifully transparent, more like the Mediterranean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason for this was two fold: a lot of effluent from the city, including sewage, was discharged into the sea, and the river Taff, which runs through Cardiff, brought down a lot of industrial effluent from the Welsh valleys. It is a matter of common sense that the sea dispersed and diluted the pollution the further away from the big city one looked. I understand that the river and the city are much cleaner now, but I think the murky waters of Melbourne which you describe are due to the same sort of causes which many years ago fouled the waters around Cardiff.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-11-11T09:35:02.170" LastActivityDate="2019-11-11T09:35:02.170" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18441" PostTypeId="1" CreationDate="2019-11-11T15:00:02.950" Score="1" ViewCount="36" Body="&lt;p&gt;I'm working on a room air quality management algorithm, and many sensors seem to respond with &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; measurements of as little as 200 ppm. Obviously a sensor giving off this value will be broken or badly calibrated, but I'm wondering about what deviations from the &quot;average&quot; &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; content of the atmosphere (400-410 ppm) could be normal, for example, because the building is located in an area with little industry, vehicles and with lots of lush vegetation. Any information would be appreciated, since I, so far, had very little luck in acquiring decent sources on this issue. &lt;/p&gt;&#xA;" OwnerUserId="18287" LastEditorUserId="2470" LastEditDate="2020-01-05T18:57:02.667" LastActivityDate="2020-01-05T18:57:02.667" Title="Natural air-CO2 deviations in the troposphere" Tags="|co2|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18442" PostTypeId="1" CreationDate="2019-11-11T16:42:04.290" Score="1" ViewCount="241" Body="&lt;p&gt;Some anthropogenic global heating (AGH) skeptics deny that any global heating is occurring. I figured out a way that could be used to refute them. A weighted average of all of the thermal points on the Earth could be computed on a daily basis. These thermal points are obtained from thermal images. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These points would be satellite resolution distance apart. This would provide an actual measure of global heating. We could subtract out the effects of cities and volcanoes by simply ignoring every value above a certain threshold. One example of such a threshold would be the average of all of the points for that day. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would this be a reasonable way to double check the trend of global temperature anomalies? &lt;/p&gt;&#xA;" OwnerUserId="17970" LastEditorUserId="6" LastEditDate="2019-11-14T14:11:07.570" LastActivityDate="2019-11-15T09:12:26.693" Title="How reliable would measuring global heating from satellite be?" Tags="|climate-change|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18443" PostTypeId="2" ParentId="18442" CreationDate="2019-11-12T00:17:19.987" Score="-4" Body="&lt;p&gt;You seem to conflate several things in your question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, AGH skeptics don't deny &quot;climate change&quot;. They don't even deny that anthropogenic activity does have some impact on thermal balance of Earth. They just don't think this impact has any significance, since the same climate scientists already have established that CO2 was 10-fold higher in the Earth past, and no water-amplified &quot;runaway&quot; effects (aka &quot;feedbacks&quot;) have lead to any terrible effects to life on Earth. It short, there was no &quot;point of no return&quot;, historically speaking. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second, you confuse &quot;global change in average surface temperature&quot; with &quot;global heating&quot;. Since the Earth is round and suffers very different insolation levels (equatorial areas are hot and radiate back quite a lot, polar areas are cold and emit much less, all in proportion to 4-th degree of absolute temperature in accord with &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stefan-Boltzmann law&lt;/a&gt;), it is easy to construct simple examples when lower &quot;average temperature&quot; leads to higher thermal emission, and higher average temperature leads to lower emission to outer space. In other words, there is no correlation between &quot;average surface temperature&quot; of the globe with global &quot;radiative imbalance&quot; (aka &quot;global heating&quot;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore obtaining thermal images from distance might show ANY type of correlation with statistical averages of surface temperatures. And I don't even mention technical difficulties related to long-term stability and calibration of remote sensors, and with necessity to get these observations for at least 100 years to see any effect. And as I noted above, the effect can be anything and prove nothing. &lt;/p&gt;&#xA;" OwnerUserId="6584" LastActivityDate="2019-11-12T00:17:19.987" CommentCount="13" ContentLicense="CC BY-SA 4.0" />
  <row Id="18444" PostTypeId="2" ParentId="18390" CreationDate="2019-11-12T10:07:41.520" Score="5" Body="&lt;p&gt;The NASA has recently lowered their recommendation for astronauts on the ISS from 7000 ppm to 5300 ppm &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;NASA has continued to lower &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; exposure levels for ISS astronauts, down from 5.3 mm Hg (7000 ppm) to “4 mm Hg [under 5300 ppm] more recently.”&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;see &lt;a href=&quot;https://thinkprogress.org/its-taking-less-co2-than-expected-to-cause-health-risks-in-astronauts-7af09e82b83/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://thinkprogress.org/its-taking-less-co2-than-expected-to-cause-health-risks-in-astronauts-7af09e82b83/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Newer studies even recommend lower values&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Law’s paper is the first serious look into the subject, and her team’s recommendation is to go even lower, to 2.5 mm Hg. They found that “for each 1-mm Hg increase in &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;, the odds of a crew member reporting a headache almost doubled.” Their recommended level of 2.5 mm would, according to the paper, “keep the risk of headache to below 1%, a standard threshold used in toxicology and aerospace medicine.”&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.airspacemag.com/daily-planet/why-living-space-can-be-pain-head-180951507/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.airspacemag.com/daily-planet/why-living-space-can-be-pain-head-180951507/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But these values are still 5-10 times as high as the average value in the atmosphere. So if the studies on astronauts are correct, there should be no reason to worry. &lt;/p&gt;&#xA;" OwnerUserId="18293" LastEditorUserId="2470" LastEditDate="2020-01-04T19:07:54.283" LastActivityDate="2020-01-04T19:07:54.283" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18446" PostTypeId="1" AcceptedAnswerId="18448" CreationDate="2019-11-12T17:16:43.613" Score="6" ViewCount="191" Body="&lt;p&gt;I got to thinking about freshwater on Antarctica. Obviously, there is a lot of freshwater ice. However, the deeper you go underground, eventually the dirt will be warmed geothermically. So does the geothermal heat melt the ice and create a lot of underground water? Or does surface ice have zero correlation with underground water?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have no idea how aquifers are technically made. This is just idle curiosity/speculation from your average Joe.&lt;/p&gt;&#xA;" OwnerUserId="18295" LastEditorUserId="2470" LastEditDate="2021-07-06T06:57:42.310" LastActivityDate="2021-07-06T06:57:42.310" Title="Does Antarctica have a lot of aquifers?" Tags="|groundwater|antarctica|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18447" PostTypeId="1" CreationDate="2019-11-12T17:43:36.953" Score="2" ViewCount="160" Body="&lt;p&gt;&lt;b&gt;EDIT 6/13/2020&lt;/b&gt;: Actual Jan average from same website was 50.3 °F, which is even above my one-sigma bound, so I failed badly.  What did I miss now that we have hindsight?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;On Nov 1, I looked at the &lt;a href=&quot;https://www.weather.gov/fwd/dmotemp&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dallas monthly weather averages&lt;/a&gt; (pasted below) and tried to predict the average temperature for Jan 2020.  It's hard to see any trend, so I would simply predict 46.2 +/- 3.5 °F.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What else should I have measured to predict this significantly better?&#xA;I was thinking about looking at solar irradiance data (with sunspot solar cycles), sea currents, or sea temperatures...what data would improve my prediction by more than 1°F?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm hoping for an answer like, &quot;Well, if you go to website X, their measurement of Y indicates that temperatures will likely deviate by Z&quot; with perhaps some science showing that this is a good way to predict long-term weather.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Year  Jan   Feb   Mar   Apr   May   Jun   Jul   Aug   Sep   Oct   Nov   Dec   Total&#xA;-----------------------------------------------------------------------------------&#xA;2019  45.8  50.2  55.0  66.0  73.4  79.9  84.6  87.4  85.5  65.5       &#xA;2018  45.8  51.1  63.3  61.6  79.0  85.7  88.8  85.2  78.1  66.2  52.5  48.4  67.1&#xA;2017  51.2  60.6  65.7  69.3  75.4  82.5  86.6  84.4  80.6  69.6  62.4  49.7  69.8&#xA;2016  47.0  55.2  61.2  68.1  72.5  84.0  87.4  85.8  81.5  74.1  63.5  49.7  69.2&#xA;2015  44.5  45.7  56.1  65.8  70.9  82.1  87.1  87.3  82.7  71.2  58.7  53.7  67.2&#xA;2014  45.3  47.0  55.1  66.3  74.4  82.4  83.8  86.2  80.3  71.6  51.5  50.1  66.2&#xA;2013  49.1  52.0  56.4  63.0  72.3  82.6  84.5  87.1  82.4  68.2  53.5  43.1  66.2&#xA;2012  50.4  52.5  64.3  70.3  77.9  84.3  87.7  86.5  80.0  67.0  59.7  51.2  69.3&#xA;2011  42.8  49.5  61.3  70.8  72.8  86.8  91.4  93.4  80.0  68.2  57.9  47.6  68.5&#xA;2010  44.3  41.7  55.8  66.7  76.9  86.5  85.9  89.8  79.8  68.8  58.5  49.3  67.0&#xA;2009  48.1  55.8  58.9  64.8  73.3  83.8  86.6  85.3  76.2  62.7  59.5  42.7  66.5&#xA;2008  46.9  54.0  61.0  66.5  77.0  86.5  89.0  86.7  78.5  69.6  59.7  49.0  68.7&#xA;2007  42.3  49.4  63.9  62.4  74.6  81.4  83.8  87.8  81.6  72.1  61.3  49.8  67.5&#xA;2006  55.1  49.4  62.2  72.0  78.0  83.7  87.7  89.8  77.6  68.1  57.5  50.0  69.3&#xA;2005  49.5  52.6  56.7  65.5  73.5  83.6  85.1  86.8  83.7  68.8  60.8  48.1  67.9&#xA;2004  48.5  45.8  61.8  66.2  74.4  79.4  83.5  81.5  78.4  72.1  57.1  48.9  66.5&#xA;2003  43.7  45.6  56.2  66.9  75.5  79.0  86.3  86.7  74.5  68.7  59.4  49.6  66.0&#xA;2002  47.6  47.0  54.8  68.4  72.0  80.1  83.2  84.7  79.6  64.9  53.8  47.7  65.3&#xA;2001  42.7  50.2  51.8  67.8  74.2  80.3  86.7  84.9  74.7  65.0  59.7  49.5  65.6&#xA;2000  50.6  57.3  61.0  65.3  76.6  80.7  87.3  90.2  80.4  69.7  49.8  39.4  67.4&#xA;1999  48.6  55.5  56.4  67.9  73.8  82.1  86.1  90.2  79.0  69.2  62.9  51.5  68.6&#xA;1998  48.4  51.1  54.9  63.8  78.5  85.5  91.6  87.8  83.6  69.5  57.6  47.0  68.3&#xA;1997  44.0  49.5  58.3  60.4  70.1  78.8  84.9  83.1  80.2  67.2  52.1  45.6  64.5&#xA;1996  43.1  52.1  53.3  64.2  79.7  82.5  86.1  82.5  74.5  66.9  54.9  49.2  65.8&#xA;1995  48.1  52.5  56.9  64.2  73.2  79.9  85.5  85.5  76.6  67.8  54.8  47.4  66.0&#xA;1994  45.7  48.6  59.0  65.9  71.5  84.1  83.9  84.0  76.3  67.3  57.9  49.0  66.1&#xA;1993  45.1  49.0  56.1  63.3  71.9  81.7  87.3  87.5  78.2  63.8  51.6  49.5  65.4&#xA;1992  46.9  54.4  59.0  66.0  71.1  79.4  84.3  80.2  77.7  69.5  52.7  49.9  65.9&#xA;1991  42.8  53.7  59.8  67.4  75.4  81.0  85.0  82.5  75.2  68.1  51.7  50.3  66.1&#xA;1990  51.8  53.9  57.7  64.0  73.4  84.0  82.5  84.6  80.0  66.4  59.8  44.0  66.8&#xA;1989  50.0  42.2  56.7  66.4  74.3  77.9  82.8  82.3  74.7  69.0  58.2  39.0  64.5&#xA;1988  42.2  47.1  56.0  64.5  72.8  80.4  85.3  87.9  79.2  65.7  58.1  49.1  65.7&#xA;1987  44.5  50.8  53.9  65.0  75.1  79.6  83.4  86.5  77.1  66.5  55.7  47.3  65.5&#xA;1986  48.8  51.2  60.2  67.2  71.5  80.8  86.4  83.4  80.2  65.7  52.4  46.1  66.2&#xA;1985  37.8  45.0  60.8  67.2  74.0  80.2  84.4  87.6  77.7  67.6  56.3  42.3  65.1&#xA;1984  39.3  50.9  56.3  63.7  73.7  82.5  85.5  85.8  76.1  67.0  54.6  52.6  65.7&#xA;1983  43.4  48.5  54.5  60.6  69.5  77.3  83.6  84.9  77.1  67.8  57.3  34.8  63.3&#xA;1982  44.6  44.5  59.8  62.5  72.5  79.2  84.6  86.7  78.1  67.0  55.6  49.2  65.4&#xA;1981  44.6  48.9  55.7  69.2  70.5  80.3  85.9  83.4  76.2  66.1  57.5  47.3  65.5&#xA;1980  45.5  46.6  54.2  63.1  75.0  87.0  92.0  88.5  80.3  65.4  54.9  49.4  66.8&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="18294" LastEditorUserId="18294" LastEditDate="2020-06-13T16:46:19.027" LastActivityDate="2020-06-13T16:46:19.027" Title="Predicting the weather in two months" Tags="|meteorology|temperature|weather-forecasting|united-states|" AnswerCount="0" CommentCount="17" ClosedDate="2020-06-15T14:45:30.297" ContentLicense="CC BY-SA 4.0" />
  <row Id="18448" PostTypeId="2" ParentId="18446" CreationDate="2019-11-12T20:40:55.110" Score="4" Body="&lt;p&gt;Yes. So far as aquifers are concerned, Antarctica is just like any other continent. The Ice is 4 kilometres thick in places, but at the bottom there is water. If there is any place where water is not found at the base of the ice sheet, there will be an aquifer within a few miles. There are about 400 sub-glacial lakes in Antarctica, the most well known being Lake Vostok in Russian Antarctic Territory. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lake Vostok is very large and deep, covered by 4 Km of ice, and Russian scientists have recently drilled down to it in the hope of finding living organisms. Although it is completely dark down there they were not disappointed, and many micro-organisms were found, but no vertebrates. There is a large, dry valley deep in Antarctica where precipitation is negligible and bare ground is everywhere, but how this affects underground water resources I don't think anyone could say.  &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-12T20:40:55.110" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18450" PostTypeId="1" CreationDate="2019-11-13T02:40:19.993" Score="3" ViewCount="73" Body="&lt;p&gt;The CDS API does not behave well on our machines.  Has anyone had any luck scripting their own ERA-5 reanalysis large-data download script?  Perhaps something that is not nearly as large, clunky, and annoying to use?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;" OwnerUserId="18298" LastEditorUserId="111" LastEditDate="2019-11-13T04:48:31.440" LastActivityDate="2019-11-13T04:48:31.440" Title="ERA-5 data downloader... other than CDS-API?" Tags="|meteorology|models|reanalysis|era|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18451" PostTypeId="1" AcceptedAnswerId="18461" CreationDate="2019-11-14T00:13:56.607" Score="2" ViewCount="193" Body="&lt;p&gt;My question is,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is the lake shown in the YouTube video &lt;a href=&quot;https://www.youtube.com/watch?v=JRhMegxuT5w&quot; rel=&quot;nofollow noreferrer&quot;&gt;Clear Lake, Oregon&lt;/a&gt; extremely pure water by volume not counting dissolved air which might be about 1 in 20 by volume?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In case you didn't realize, even pure water probably can absorb a significant fraction visible light even in the region with the lowest absorbtivity. I'm guessing that lake has essentially the same absorbtion spectrum in visible light as pure water and that you pretty much cannot see more than 200 meters through water at all based on my observation of that video. I guess it's technically correct to say it's extremely pure but is not extremely clear. Since pure water itself is not completely clear, I cannot tell for sure by observation that it doesn't have a solute with colour in it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I believe the lake shown in the YouTube video &lt;a href=&quot;https://www.youtube.com/watch?v=XAMLGB0hUmk&quot; rel=&quot;nofollow noreferrer&quot;&gt;Adventure Oregon - Lost Lake draining into a giant hole&lt;/a&gt; is the exact same lake. I don't know that so I will specify that I'm asking about the one in the YouTube video &lt;a href=&quot;https://www.youtube.com/watch?v=JRhMegxuT5w&quot; rel=&quot;nofollow noreferrer&quot;&gt;Clear Lake, Oregon&lt;/a&gt; even if it's a different lake. According to the YouTube video &lt;a href=&quot;https://www.youtube.com/watch?v=XAMLGB0hUmk&quot; rel=&quot;nofollow noreferrer&quot;&gt;Adventure Oregon - Lost Lake draining into a giant hole&lt;/a&gt;, the lost lake of Oregon is a seasonal lake. If they are the exact same lake, could the purity be caused by the drain hole? If the drain hole really is in the lowest part of the lake, could the fact that water is constantly draining and getting replaced by rain water prevent and dirt from getting stirred up and lingering in the water? In the video with the full lake, there was also grass on the floor of the lake which is a sign that the lake might be a seasonal like and therefore might be the same lake as the one in the other video. Maybe also because of the drain hole, any slight bit of the type of moss suited for water dies off after the lake drains and its floor dries so there's no moss to break off microscopic fragments into the water and make it appear green.&lt;/p&gt;&#xA;" OwnerUserId="4846" LastActivityDate="2019-11-18T20:16:23.297" Title="Is Oregon lake extremely pure water? If so, why?" Tags="|geography|lakes|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18452" PostTypeId="1" CreationDate="2019-11-14T01:11:23.933" Score="5" ViewCount="87" Body="&lt;p&gt;I often hear that tornadoes die when the RFD (&lt;a href=&quot;https://en.wikipedia.org/wiki/Rear_flank_downdraft&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rear Flank Downdraft&lt;/a&gt;) strengthens and destroys their source of inflow... How do tornadoes get any inflowing updrafts when they are embedded in rain? How can they sustain themselves?&lt;/p&gt;&#xA;" OwnerUserId="18303" LastEditorDisplayName="user1066" LastEditDate="2019-11-14T01:27:27.023" LastActivityDate="2019-11-14T01:27:27.023" Title="Why aren't tornadoes embedded in squall lines or tornadoes in high-precipitation supercells destroyed by downdrafts?" Tags="|meteorology|tornado|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18453" PostTypeId="1" CreationDate="2019-11-14T04:32:20.233" Score="1" ViewCount="137" Body="&lt;p&gt;I need 6-hour MERRA-2 reanalysis data to do some research.&#xA;I downloaded the data from this website:&#xA;&lt;a href=&quot;https://disc.gsfc.nasa.gov/datasets/M2I6NPANA_5.12.4/summary?keywords=merra&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://disc.gsfc.nasa.gov/datasets/M2I6NPANA_5.12.4/summary?keywords=merra&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I used ncview to check this data, I found that V and U wind are missing values over land at 1000 hPa pressure level.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ah2oW.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ah2oW.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;Have you ever seem this problem before? &#xA;Thank you so much.&lt;/p&gt;&#xA;" OwnerUserId="14589" LastActivityDate="2019-11-19T17:02:53.457" Title="MERRA-2 Reanalysis data V and U wind are missing values over land at 1000 hPa pressure level" Tags="|reanalysis|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18454" PostTypeId="1" AcceptedAnswerId="18457" CreationDate="2019-11-14T10:31:58.913" Score="3" ViewCount="48" Body="&lt;p&gt;I have a grid shapefile that has a resolution of 1km x 1km. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This grid is then used to spatially allocate road emissions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My goal is to get the emissions in the unit: &lt;strong&gt;μg m-2 s-1(microgram per square meter per second)&lt;/strong&gt; since this is the emission unit for aerosols in the WRF/Chem&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I manage to get the emissions for a certain grid cell by multiplying the total emissions in (micrograms/s) to the ratio of the road length present inside the grid cell to the total road length&lt;a href=&quot;https://i.stack.imgur.com/9snhv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9snhv.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now I have the emission for that grid cell in &lt;strong&gt;μg s-1&lt;/strong&gt; (micrograms/second).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question may be silly or simple, but I am thinking if I still need to divide my emissions by 1000 (since 1km = 1000m) to get the final emission unit I need &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Final unit needed:  &lt;strong&gt;μg m-2 s-1(microgram per square meter per second)&lt;/strong&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Am I right? Hoping someone could help me with this. Thanks!&lt;/p&gt;&#xA;" OwnerUserId="17926" LastActivityDate="2019-11-14T14:34:17.333" Title="Spatial allocation of road emissions and unit conversion" Tags="|wrf|wrf-chem|emissions|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18455" PostTypeId="2" ParentId="18451" CreationDate="2019-11-14T10:53:22.980" Score="2" Body="&lt;p&gt;The lake is very clean and pure by the standards of some other lakes, but there are bound to be some harmless and beneficial impurities in there. The plants couldn't grow unless there was plenty of CO2 in the water, and it follows there is also oxygen. Nitrogen is dissolved from the air and nitrogen oxides are brought in by the rain. I would be very surprised if there were no calcium carbonate and other dissolved minerals in there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The lake is fed by clear mountain streams and drains into an aquifer, so never becomes stagnant. If it were a seasonal lake and dry for part of the year, the abundant water weed couldn't grow. The water weeds help purify and oxygenate the water, and are a good sign. I would expect to find plenty of fish in there if there are not too many anglers taking them away. If you put a sample of the water under a microscope you would find plenty of mostly photosynthetic micro-organisms in it, but not enough to cloud the water to any significant extent. I doubt if it is the same lake you saw in the other video.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-14T10:53:22.980" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18456" PostTypeId="2" ParentId="18442" CreationDate="2019-11-14T14:08:50.740" Score="5" Body="&lt;p&gt;Measuring long-term temperature trends from satellites is possible, but difficult due to a variety of reasons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is ongoing research.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short: the satellites that have been around long enough were built for measuring weather, not climate, and the standards to which instruments need to be built to measure one are entirely different from the other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We have had satellite measurements of the atmosphere since the 1960s, and operationally since the late 1970s.  Those have always included infrared radiometer measurements, which means that, in principle, we can construct a record of surface (both land and sea) and atmospheric temperatures for the past 40 years at least.  The sensors themselves aren't very complicated — but to determine a trend we would need to be very confident about their uncertainty, stability, and inter-satellite variability.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you were to simply take 40 years of HIRS infrared measurements and plot them, you don't know if the changes are due to atmospheric or instrumental changes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From 2015 to 2019, I was part of the &lt;a href=&quot;http://www.fiduceo.eu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;FIDUCEO&lt;/a&gt; project which aimed to bring the science of metrology (science of measurement) to satellite observations.  Taking 40 years of AVHRR (for sea surface temperature) or HIRS (for atmospheric temperature and humidity) measurements, with 16 different editions of the instrument over a period of 40 years.  But AVHRR was built to look at pictures of clouds.  If you look at pictures of clouds, the user doesn't care if one satellite has its pictures 0.5% brighter than the previous one.  They just tweak their monitor a bit!  But if you take the global climate system, then that corresponds to more than 1K temperature difference, which for the oceans, would be huge.  In FIDUCEO, we aimed to:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Develop a metrology of Earth Observation&lt;/li&gt;&#xA;&lt;li&gt;Produce &lt;em&gt;Fundamental Climate Data Records&lt;/em&gt; (FCDRs) for various operational meteorological instruments in visible, infrared, and microwave, meaning:&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Per-datum metrologically traceable uncertainty characterisation;&lt;/li&gt;&#xA;&lt;li&gt;Per-datum information on correlation structures: which component of the error estimate cancels out when averaging and which component remains;&lt;/li&gt;&#xA;&lt;li&gt;Harmonisation between the various satellite sensors.&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Here are 40 years of &lt;a href=&quot;https://www.wmo-sat.info/oscar/instruments/view/183&quot; rel=&quot;nofollow noreferrer&quot;&gt;HIRS&lt;/a&gt; (versions 2, 3, and 4), on which we tried to do some harmonisation.  The top panel shows global average brightness temperature per 24-hour period, as measured by channel 2 which IIRC peaks somewhere in the stratosphere, so this would correspond roughly to an atmospheric temperature somewhere up in the stratosphere (which, incidentally, is cooling as the Earth's surface is warming):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8VVFZ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8VVFZ.png&quot; alt=&quot;40 years of HIRS&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The different colours indicate different satellites.  As you can see, there are both jumps between satellites, and trends within one satellite.  Some of this is expected, as polar-orbiting sun-synchronous satellites have a drifting local equator crossing time, but some of it is due to instrumental problems.  Some of those problems are captured by the structured uncertainty in the bottom panel, but not all of it.  The data only go back to the mid-1980s, because before that, there weren't enough overlaps to constrain the differences between subsequent pairs of satellites based on simultaneous nadir overpasses (SNOs).  For satellites in the early 1980s and late 1970s, the coefficients to calibration the thermometres measuring the temperature of the on-board calibration target appear to have been lost.  For the earliest satellites the header data does not match available documentation.  Software to produce this figure is &lt;a href=&quot;https://github.com/fiduceo/FCDR_HIRS&quot; rel=&quot;nofollow noreferrer&quot;&gt;on Github&lt;/a&gt;, raw source data are available &lt;a href=&quot;https://www.bou.class.noaa.gov/saa/products/welcome&quot; rel=&quot;nofollow noreferrer&quot;&gt;from NOAA CLASS&lt;/a&gt;, some processed data from &lt;a href=&quot;http://www.fiduceo.eu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;FIDUCEO&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is for a global average.  To do this regionally would add additional complications.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.wmo-sat.info/oscar/satelliteprogrammes/view/21&quot; rel=&quot;nofollow noreferrer&quot;&gt;CLARREO&lt;/a&gt; programme is proposed to be the first in-orbit SI reference for accurate calibration.  Had we had that for the past 40 years, our job would be easier.  But CLARREO is still waiting for funding.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the answer to your question is: with what we have now — not good enough — yet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But if you are contemplating a career in satellite techno-archeology, I recommend it.  It's great fun.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2019-11-15T09:12:26.693" LastActivityDate="2019-11-15T09:12:26.693" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18457" PostTypeId="2" ParentId="18454" CreationDate="2019-11-14T14:34:17.333" Score="2" Body="&lt;p&gt;You have got your emissions over a square kilometer. To get to square meters you divide by 1000000 since &lt;span class=&quot;math-container&quot;&gt;$1km^2=10^6m^2$&lt;/span&gt;.&lt;/p&gt;&#xA;" OwnerUserId="681" LastActivityDate="2019-11-14T14:34:17.333" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18458" PostTypeId="2" ParentId="18451" CreationDate="2019-11-14T17:18:14.093" Score="3" Body="&lt;p&gt;The visibility or &quot;clearness&quot; is more a matter of suspended particulates, and organic material such as algae, than of dissolved material.  For instance, runoff from glacial streams can be nearly opaque due to suspended rock flour, yet &quot;pure&quot; in the common sense of not having much in the way of algae &amp;amp;c. Conversely, some parts of the oceans can be very transparent due to lack of suspended sediment &amp;amp; organic matter, yet still have the same dissolved salts as other parts of the ocean.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2019-11-14T17:18:14.093" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18459" PostTypeId="1" AcceptedAnswerId="18460" CreationDate="2019-11-14T17:18:43.237" Score="4" ViewCount="2065" Body="&lt;p&gt;The new Mac OS boasts a beautiful default desktop background with the western tip of Santa Catalina Island.  The rock formation in the foreground looks like it was sliced on the diagonal with a power tool, but I assume this uninhabited side of the island hasn't actually been altered.  What accounts for this smooth rock face?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3QPcD.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3QPcD.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4611" LastActivityDate="2019-11-14T20:54:03.443" Title="What's the story of the shear face in the new Mac OS Catalina wallpaper?" Tags="|geology|california|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18460" PostTypeId="2" ParentId="18459" CreationDate="2019-11-14T20:54:03.443" Score="2" Body="&lt;p&gt;This is a bedding plane, once horizontal, but geological forces have tilted it to the diagonal. The strata above have been eroded and washed into the sea, perhaps by a storm, leaving the ancient bedding plane exposed. Tilted strata are not unusual in very ancient rock formations.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-14T20:54:03.443" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18461" PostTypeId="2" ParentId="18451" CreationDate="2019-11-15T00:10:17.440" Score="2" Body="&lt;p&gt;Clear lake is clear for a number of reasons.  One, most of the water flowing into the lake is from subsurface, so the water is coming up through sediments, i.e. filtered.  Two it is the water supply area for Eugene Oregon, and therefore road and forestry activities are held to a higher standard, reducing the amount of sediment from runoff in the surrounding area.  Three, the lake is very cold reducing algae or organic particulates in the water.  Overall there is little in the way of inorganic particulate entering the lake and little opportunity for organic particulates to develop.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wiki and the state forest service has some limited data on this lake: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Clear_Lake_(Linn_County,_Oregon)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wiki&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.fs.usda.gov/recarea/willamette/recarea/?recid=4399&quot; rel=&quot;nofollow noreferrer&quot;&gt;Forest Service Description&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user824" LastEditorDisplayName="user824" LastEditDate="2019-11-18T20:16:23.297" LastActivityDate="2019-11-18T20:16:23.297" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18462" PostTypeId="2" ParentId="18422" CreationDate="2019-11-15T03:06:45.887" Score="8" Body="&lt;p&gt;you are missing a big factor, the plates are not moving due to the momentum of an initial impulse. They are being actively moved by the push and pull of mantle convection. Much like how icebergs are pulled along by ocean currents. the iceberg analog however breaks down because icebergs melt before they can do much complex interaction, where as continental plate material is more or less permanent. also icebergs are subjected to far lower forces than continents, a closer analogy would be ice in glacier. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The amount of energy the mantle is supplying is massive, far far more proportionally than an iceberg is subjected to, more than enough to drive continental plate together and build mountains.  if you are interested in the detailed mathematics you can start &lt;a href=&quot;https://www.ocean.washington.edu/courses/oc545/Reading/Ogawa_MantleConvection.pdf&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The continents float on the mantle becasue they are less dense, but they are moved by mantle movement transferring energy. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2019-11-15T04:44:15.980" LastActivityDate="2019-11-15T04:44:15.980" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18463" PostTypeId="1" CreationDate="2019-11-15T03:22:49.473" Score="1" ViewCount="52" Body="&lt;p&gt;I have been drinking natural unfiltered raw water straight from rivers, streams, springs and ponds and I haven’t ever gotten sick from it. I strongly believe and know it in my heart that water from springs, rivers, streams and ponds is cleaner and better for you than tap water and filtered processed water that we get which isn’t natural water. If I’ve never gotten sick from it than it’s okay right?&lt;/p&gt;&#xA;" OwnerUserId="17923" LastActivityDate="2019-11-15T08:05:45.420" Title="Natural Raw Water" Tags="|water|rivers|" AnswerCount="1" CommentCount="3" ClosedDate="2019-11-15T13:40:12.600" ContentLicense="CC BY-SA 4.0" />
  <row Id="18464" PostTypeId="2" ParentId="18463" CreationDate="2019-11-15T08:05:45.420" Score="1" Body="&lt;p&gt;It all depends where you are and how carefully you choose your water sources. In the Malaysian jungle (peninsular Malaya and Sarawak), I used natural water sources all the time for years on end without ill consequences. There are numerous springs and small streams where the water is always good, but we never used a main river where there was habitation upstream. On rare occasions we used a wild pig wallow, provided the water was crystal clear. On even rarer occasions I have used natural water sources when camping in the British countryside, where even more care is required. One never knows what chemicals may have got into the run off, though up in the hills it is safer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You may have a very good immune system, but not all people have. Usually I used natural water sources when there was no other choice, but in an inhabited area I would choose tap water if it was easily obtainable. It is the opinion of the medical profession that tap water is just as good for you as natural water, and carries less risk.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-15T08:05:45.420" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18465" PostTypeId="1" CreationDate="2019-11-15T14:32:06.370" Score="1" ViewCount="67" Body="&lt;p&gt;We all have basic ideas about planets and their seasons..But my question is that why do NEPTUNE and EARTH have similar seasons although their compositions are completely different..On earth Nitrogen dominates the atmosphere while on neptune Hydrogen dominates..Are seasons defined on axial tilt basis only?? Coz the axial tilt of earth is 23.5 and of neptune is 28.3( Both in degrees)..&lt;/p&gt;&#xA;" OwnerUserId="18312" LastEditorUserId="18312" LastEditDate="2021-09-03T04:23:55.220" LastActivityDate="2021-09-03T04:23:55.220" Title="Similarity of seasons on Neptune and Earth" Tags="|planetary-science|" AnswerCount="0" CommentCount="3" ClosedDate="2019-11-17T20:38:45.460" ContentLicense="CC BY-SA 4.0" />
  <row Id="18467" PostTypeId="1" CreationDate="2019-11-15T17:12:06.280" Score="1" ViewCount="34" Body="&lt;p&gt;The presence of nearby rainforest is known to measurably deplete the local atmospheric &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; content, but how much would &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;-hungry crops reduce local &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; and which crop would deplete it most? My guess is that maize would be among the most &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;-hungry crops. Could anything compete with rainforest?&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="2470" LastEditDate="2020-01-05T18:54:45.557" LastActivityDate="2020-01-05T18:54:45.557" Title="Which Farm Crops Are Most Efficient at Reducing Local CO2?" Tags="|co2|farm|rainforest|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18468" PostTypeId="1" AcceptedAnswerId="18478" CreationDate="2019-11-15T17:46:09.047" Score="4" ViewCount="116" Body="&lt;p&gt;Researchers who are involved in study of life on Mars are saying that there might be multicellular life present on Mars, today or in the past. Which traces, markers or environments on Mars could support this hypothesis and how it will be investigated?&lt;/p&gt;&#xA;" OwnerUserId="18312" LastEditorUserId="1411" LastEditDate="2019-11-18T18:26:13.230" LastActivityDate="2019-11-18T18:26:13.230" Title="Which markers could suggest that there was extinct or extant life on Mars?" Tags="|planetary-science|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18469" PostTypeId="2" ParentId="18468" CreationDate="2019-11-15T18:47:06.743" Score="1" Body="&lt;p&gt;It is highly improbable that multicellular life evolved on Mars. It took billions of years for it to evolve on Earth, and it is not thought that benign conditions existed for that long on Mars. If there ever were multicellular organisms on Mars, they can only be of a microscopic sort and would have left fossils in the rocks. One of the things geologists will be looking for when they explore Mars are microfossils, and these are more likely to be of a unicellular kind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On Earth, the earliest sign of life (3.8 billion years)is a type of graphite which can only be produced by living organisms, so to find some on Mars would cause a sensation. Unicellular microfossils have been found in Australian chert and dated at 3.5 billion years, a time at which benign, Earth-like conditions existed on Mars.I personally doubt that there ever was life of any kind on Mars, but would be delighted to be proved wrong.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-15T18:47:06.743" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18470" PostTypeId="1" AcceptedAnswerId="18471" CreationDate="2019-11-15T21:42:04.600" Score="5" ViewCount="190" Body="&lt;p&gt;Recently at the American Museum of Natural History in New York, I saw a display set that claimed erosion makes mountains rise higher, counterintuitively. The explanation was that the material removed from a mountain due to erosion makes it much lighter. Since the mountain sits on a landmass that is floating atop magma, a lighter landmass rises higher. (Similarly, boats rise higher in water when weight is removed from them.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have been looking for resources online to confirm this, but none mention it. They tend to claim that pressure due to shifting tectonic plates is the cause of mountain growth, and if they mention erosion at all, they only discuss it as a possible shrinking factor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What do actual geologists have to say about this? Does it depend on the mountain range?&lt;/p&gt;&#xA;" OwnerUserId="17342" LastActivityDate="2019-11-16T00:01:03.613" Title="Does erosion make mountains become higher?" Tags="|plate-tectonics|mountains|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18471" PostTypeId="2" ParentId="18470" CreationDate="2019-11-15T23:28:39.517" Score="7" Body="&lt;p&gt;This actually does happen, a feedback loop between the &lt;a href=&quot;https://en.wikipedia.org/wiki/Himalayas&quot; rel=&quot;noreferrer&quot;&gt;Himalayas&lt;/a&gt; and the Indian &lt;a href=&quot;https://en.wikipedia.org/wiki/Monsoon&quot; rel=&quot;noreferrer&quot;&gt;monsoon&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Indian_Plate&quot; rel=&quot;noreferrer&quot;&gt;Indian Plate&lt;/a&gt; is actively shoving itself under the &lt;a href=&quot;https://en.wikipedia.org/wiki/Eurasian_Plate&quot; rel=&quot;noreferrer&quot;&gt;Eurasian Plate&lt;/a&gt;, creating the Himalayas. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the same time, monsoon storms come up against the southern side of the Himalayas. The high mountains enhance the storms' rainfall, and the mountains erode much more on the southern side than the northern side.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Material is transported from the Eurasian Plate down onto the Indian Plate, and the weight removed from the mountains causes &lt;a href=&quot;https://en.wikipedia.org/wiki/Isostasy&quot; rel=&quot;noreferrer&quot;&gt;isostatic&lt;/a&gt; rebound of the Eurasian Plate, allowing the Indian plate to slide underneath, enhancing the uplift of the Himalayas., keeping the monsoon rainfall on their south side, etc. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's a more detailed explanation and some nice images &lt;a href=&quot;http://recherche.crpg.cnrs-nancy.fr/spip.php?article1150&amp;amp;lang=en&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2019-11-16T00:01:03.613" LastActivityDate="2019-11-16T00:01:03.613" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18472" PostTypeId="2" ParentId="18470" CreationDate="2019-11-15T23:44:35.327" Score="0" Body="&lt;p&gt;It depends where the mountain is. Usually it is plate tectonics or volcanism that makes mountains higher, but in some circumstances it could be erosion. During the Ice Age,there were a couple of kilometres of ice pressing down on northern Britain. When the ice melted, it did so quite rapidly in geological terms. The ice not only disappeared, but torrents of meltwater scoured the valleys and added to the erosion. Relieved of so much weight, northern Britain, including Scottish mountains, rose up, while a see-saw effect caused southern Britain to sink. I don't think the Scottish mountains rose by any great amount, but I couldn't quote you a figure offhand. Erosion will gradually revert to its traditional role and the Scottish mountains will be ground down again and washed into the sea. The rising was a brief and temporary phenomenon on a geological timescale.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-15T23:44:35.327" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18473" PostTypeId="2" ParentId="18451" CreationDate="2019-11-16T05:55:39.513" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;I believe the lake shown in the YouTube video Adventure Oregon - Lost Lake draining into a giant hole is the exact same lake.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That is incorrect, and that incorrect hypothesis resulted in a lot of incorrect reasoning. These are not the same lake. They are however close to one another. I apologize for being so harsh.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lost Lake is a shallow, transient lake that disappears each summer. While it has no outlets above the ground, it has a number of outlets into the ground. The rock in the vicinity of Lost Lake (and also in the vicinity of the nearby Clear Lake) is very porous volcanic rock. A number of other lakes in the vicinity suffer the same fate as Lost Lake: They get lost in the summer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clear Lake, &lt;a href=&quot;https://www.google.com/maps/dir/Lost+Lake+Lava+Tube,+Lost+Lake,+Sisters,+OR+97759/Clear+Lake,+Oregon/@44.3962693,-122.0253536,12z&quot; rel=&quot;nofollow noreferrer&quot;&gt;about 11 miles from Lost Lake by road&lt;/a&gt;, and about half that distance as the crow flies, does not suffer the same fate. Due to volcanic dams created a few thousand year ago, Clear Lake is much deeper than are the nearby Lost Lake, Fish Lake, and others. Clear Lake at 175 feet deep is a permanent, year-round lake. In fact, the underground waters from nearby sources such as Lost Lake and Fish Lake comprise the majority of the water flowing into Clear Lake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Like those nearby lakes, Clear Lake also suffers a good amount of underground water loss. This is one of the key reasons that it wasn't artificially dammed. The leakiness is however more than compensated by the influx from the even leakier lakes such as Lost Lake and Fish Lake. The end result is that Clear Lake not only drains below ground, it also drains above ground to form the headwaters of the McKenzie River.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to why Clear Lake is so clear, that's partly because it's fed primarily from underground sources that filter out most of the particulate matter before the water reaches the lake, and partly because the waters are so very cold. While life can survive at 40°F (4°C), it survives &lt;em&gt;slowly&lt;/em&gt;. &lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2019-11-16T06:18:37.390" LastActivityDate="2019-11-16T06:18:37.390" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18474" PostTypeId="1" CreationDate="2019-11-16T06:37:12.427" Score="3" ViewCount="41" Body="&lt;p&gt;I want to download Vertical Velocity data in the MERRA Reanalysis.&#xA;But I can not find it even I carefully went through the entire list of MERRA data.&#xA;This is the website I searched through: &lt;a href=&quot;https://disc.gsfc.nasa.gov/datasets?keywords=%22MERRA-2%22&amp;amp;page=1&amp;amp;source=Models%2FAnalyses%20MERRA-2&quot; rel=&quot;nofollow noreferrer&quot;&gt;enter link description here&lt;/a&gt;&#xA;Could you give me some hints?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you so much.&lt;/p&gt;&#xA;" OwnerUserId="14589" LastActivityDate="2019-11-16T06:37:12.427" Title="Where I can download Vertical Velocity data in the MERRA Reanalysis" Tags="|reanalysis|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18475" PostTypeId="1" AcceptedAnswerId="18477" CreationDate="2019-11-16T09:08:27.920" Score="7" ViewCount="896" Body="&lt;p&gt;These are from the movie &lt;a href=&quot;https://g.co/kgs/JhQKWg&quot; rel=&quot;noreferrer&quot;&gt;Insomnia&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EdxnZ.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EdxnZ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vuXnI.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vuXnI.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also available in &lt;a href=&quot;https://www.youtube.com/watch?v=brHA3CF4_Mw&amp;amp;t=4&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt; video from 4 seconds to 8 seconds. What is the name of this landform? Are these just snow on &lt;a href=&quot;https://www.britannica.com/science/lapies&quot; rel=&quot;noreferrer&quot;&gt;Lapies&lt;/a&gt;? or These are some form of glaciated landform? &lt;/p&gt;&#xA;" OwnerUserId="18322" LastActivityDate="2019-11-16T12:50:28.147" Title="What is the name of this landform?" Tags="|glaciology|groundwater|snow|land-surface|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18476" PostTypeId="2" ParentId="18475" CreationDate="2019-11-16T09:58:52.113" Score="1" Body="&lt;p&gt;The terrain in the photo is a glacier. There have been a number of incidents since early in World War 2 where aircraft have crashed into or attempted to land on glaciers in the Andes or Greenland, usually with catastrophic results. The aircraft concerned were usually large, multi-engine bombers or airliners. Occasionally there were a few survivors. With improvements in radar, weather forecasting and aircraft, such accidents are much less likely nowadays.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-16T09:58:52.113" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18477" PostTypeId="2" ParentId="18475" CreationDate="2019-11-16T12:50:28.147" Score="12" Body="&lt;p&gt;This is a large glacier calving event. Calving occur at the front of the glacier, probably a very wet (and likely warm based) glacier where a considerable amount of water is flowing out of the system (thus from the glacier to the sea). The amount of water is important as it can accelerate the ice flow speed on the valley floor, enabling the breaking of big ice chunks along the way. This is what typical calving events looks like: &lt;a href=&quot;https://pubs.usgs.gov/of/2004/1216/c/images/calving1.gif&quot; rel=&quot;noreferrer&quot;&gt;https://pubs.usgs.gov/of/2004/1216/c/images/calving1.gif&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the glacier ice is moving fast in a valley, and encounter hard rock outcrops on the valley floor followed by sudden drops in topography the ice will break, making it what is known as an ice fall: &lt;a href=&quot;https://pubs.usgs.gov/of/2004/1216/i/images/icefall1.gif&quot; rel=&quot;noreferrer&quot;&gt;https://pubs.usgs.gov/of/2004/1216/i/images/icefall1.gif&lt;/a&gt; , or if the topography is moderate, seracs instead &lt;a href=&quot;https://pubs.usgs.gov/of/2004/1216/s/images/serac1.gif&quot; rel=&quot;noreferrer&quot;&gt;https://pubs.usgs.gov/of/2004/1216/s/images/serac1.gif&lt;/a&gt; .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But typical events of normal glacier dynamics as aforementioned does only answer a part of the question. What happened in these picture is that the glacier chunks went seaborne, in a fjord, after a big calving event. The fjord prevent the glacier fragments to spread, forcing these to move along the fjord. This next picture as reported by ABC news show a big calving event that happened in Greenland in 2018, similar to the picture you are showing:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QqNMa.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QqNMa.jpg&quot; alt=&quot;Tabular icebergs float in the Sermilik Fjord after a large calving event at the Helheim glacier near Tasiilaq, Greenland, June 23, 2018. Source: ABC News https://abcnews.go.com/International/watch-billions-tons-ice-collapse-climate-change-impacting/story?id=57972318&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Source and caption: Tabular icebergs float in the Sermilik Fjord after a large calving event at the Helheim glacier near Tasiilaq, Greenland, June 23, 2018. Source: ABC News &lt;a href=&quot;https://abcnews.go.com/International/watch-billions-tons-ice-collapse-climate-change-impacting/story?id=57972318&quot; rel=&quot;noreferrer&quot;&gt;https://abcnews.go.com/International/watch-billions-tons-ice-collapse-climate-change-impacting/story?id=57972318&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here we see the perspective of the rock walls on both sides preventing the spreading and concentrating the glacier chunks.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2019-11-16T12:50:28.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18478" PostTypeId="2" ParentId="18468" CreationDate="2019-11-16T13:40:23.737" Score="4" Body="&lt;p&gt;One of the next big missions to Mars, named &lt;a href=&quot;https://mars.nasa.gov/mars2020/&quot; rel=&quot;noreferrer&quot;&gt;Mars 2020&lt;/a&gt; is planned to depart from Earth to Mars during late July 2020. This mission involve a &lt;a href=&quot;https://mars.nasa.gov/mars2020/mission/rover/&quot; rel=&quot;noreferrer&quot;&gt;very capable rover&lt;/a&gt;, like &lt;a href=&quot;https://mars.nasa.gov/msl/home/&quot; rel=&quot;noreferrer&quot;&gt;Curiosity&lt;/a&gt; on steroids. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the mission site:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The mission takes the next step by not only seeking signs of habitable conditions on Mars in the ancient past, but also searching for signs of past microbial life itself. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This mean that there is two important objective: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;to find &lt;strong&gt;extinct life forms&lt;/strong&gt;, such as assuming there was conditions a long time ago permitting lifeforms to exist on Mars, likely 3-3.5 Billion years from now or so, in other words, fossils. Why 3-3.5 Gy ago? This was during Hesperian geological epoch when water was likely a major agent in forming channels lakes and rivers, thus with atmospheric and ground conditions possibly permitting the existence of life back then.&lt;/li&gt;&#xA;&lt;li&gt;to find &lt;strong&gt;extant life forms&lt;/strong&gt; such as bacteria that are existing presently on Mars surface or near surface.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;One component of the mission is to sample rocks that are likely lifebearing, analyze and store for a later pickup by a further mission. Lifebearing rocks in that case may be found as old lake beds, for example iron rich lacustrine mudstone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lacustrine mudstone is obviously originating from depositing fine sediments over a lake floor, a stable environment through a long time, as shown by layers like &lt;a href=&quot;https://www.nasa.gov/jpl/msl/pia19074&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt; (pictured by Curiosity's MastCam in 2014). And iron rich is important as this chemical arrangement is favoring and helping the preservation of microbial lifeforms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lyLXK.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lyLXK.jpg&quot; alt=&quot;Jezero Crater, Mars&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.nasa.gov/image-feature/jezero-crater-mars-2020s-landing-site&quot; rel=&quot;noreferrer&quot;&gt;https://www.nasa.gov/image-feature/jezero-crater-mars-2020s-landing-site&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As can be seen in the picture, the big circle (as a crater) in the center of the delta is named the Jezero crater and is the target landing site for Mars 2020. This delta was formed due to water flowing in a lake; clay rich deposited were detected in the area. The crater is exposing deeper (early) layers in the delta, making this an ideal exploration site to look for extinct or extinct life.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2019-11-16T13:40:23.737" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18482" PostTypeId="1" CreationDate="2019-11-17T00:30:13.383" Score="7" ViewCount="344" Body="&lt;p&gt;I have read that perhaps the largest reason that tropical cyclones are so rare in the South Atlantic is due to chronically-high vertical wind shear which inhibits their structural development. &lt;strong&gt;But what are the underlying meteorological causes of this high vertical wind shear?&lt;/strong&gt; And are these inherent to the South Atlantic's bathymetry and surrounding geography or could the wind shear decrease with variations in forcings like axial tilt, greenhouse gas concentrations, the effects of a change in global ice cover, et cetera?&lt;/p&gt;&#xA;" OwnerUserId="17317" LastActivityDate="2019-11-17T00:30:13.383" Title="Why is wind shear consistently high in the South Atlantic?" Tags="|meteorology|atmosphere|climate|tropical-cyclone|climatology|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18483" PostTypeId="1" CreationDate="2019-11-17T16:06:32.670" Score="2" ViewCount="312" Body="&lt;p&gt;I have heard that the Appalachian Mountains is qualified as a temperate rainforest. What qualifies a temperate rainforest and what makes the Appalachian Mountains a temperate rainforest?&lt;/p&gt;&#xA;" OwnerUserId="17923" LastActivityDate="2021-01-13T09:09:03.027" Title="Temperate Rainforests" Tags="|mountains|rain|rainforest|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18484" PostTypeId="1" CreationDate="2019-11-17T17:03:05.637" Score="5" ViewCount="97" Body="&lt;p&gt;I found the following web-page which contains a dramatic degree-by-degree account of how climate change could play out in the future: &lt;a href=&quot;http://globalwarming.berrens.nl/globalwarming.htm&quot; rel=&quot;noreferrer&quot;&gt;http://globalwarming.berrens.nl/globalwarming.htm&lt;/a&gt;. It is more frightening than most other descriptions of the effects of global warming, and it contains no references to scientific literature or any evidence for the claims it makes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Following is a summarised version of the claims that the text makes:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;At two degrees Celsius of warming, many major cities will be underwater, causing half of humanity to be displaced.&lt;/li&gt;&#xA;&lt;li&gt;If the world warms by two degrees, avoiding three degrees of climate change would be unlikely.&lt;/li&gt;&#xA;&lt;li&gt;At anything over two degrees of warming, millions or even billions could face starvation.&lt;/li&gt;&#xA;&lt;li&gt;Once three degrees of warming is reached, more warming is inevitable and societal collapse would ensue.&lt;/li&gt;&#xA;&lt;li&gt;There are also more, dramatic events that are claimed will occur.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;To what extent (if at all) are the effects exaggerated? What is the degree of uncertainty about the scenarios for each degree of warming? Does the page represent the &quot;consensus&quot; scientific view?&lt;/p&gt;&#xA;" OwnerUserId="18329" LastEditorUserId="18329" LastEditDate="2019-11-17T18:40:45.550" LastActivityDate="2019-11-17T18:40:45.550" Title="Is this description of the effects of global warming supported by scientific research?" Tags="|climate-change|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18485" PostTypeId="2" ParentId="18483" CreationDate="2019-11-17T18:15:16.710" Score="1" Body="&lt;p&gt;The definition of temperate rainforest is rather vague and varies around the world, but in general they are forests well away from the tropics which have a mild, damp climate, and prolific rainfall. Trees can be coniferous, evergreen broadleaf or deciduous broadleaf. Welsh rainforest (I prefer to call it woodland) is mainly deciduous oak, and rather bleak in winter. I have no experience of Appalachia, but I do have experience of rainforest in the west of Britain and rainforest in Malaya and Borneo, so I'm in a good position to make a comparison. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyone hoping to see rainforest in Britain which bears any resemblance to the rainforests of Malaysia will surely be disappointed, though in some other parts of the world there are temperate rainforests with a sub-tropical flavour. This is not to say that in UK rainforests there is nothing worth seeing. There is quite a lot, particularly in summer, and the same is probably true of Appalachian rainforests. Our UK rain forests are particularly rich in lichens, for those with an interest in lichens. Unfortunately some British rainforests are in danger of being taken over by rhododendrons, which are an invasive species and not native. Tropical rainforests are incomparably richer in species, plants as well as animals, but have the disadvantage that they are also far more dangerous.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-17T18:15:16.710" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18489" PostTypeId="1" CreationDate="2019-11-18T00:45:09.260" Score="1" ViewCount="40" Body="&lt;p&gt;What time of the year does it rain the least in the Great Smoky Mountains National Park and what month gets the least amount of thunderstorms &lt;/p&gt;&#xA;" OwnerUserId="17923" LastActivityDate="2019-11-18T03:56:03.693" Title="Thunderstorms in the Great Smoky Mountains" Tags="|thunderstorm|rain|" AnswerCount="0" CommentCount="0" ClosedDate="2019-11-20T12:00:21.237" ContentLicense="CC BY-SA 4.0" />
  <row Id="18491" PostTypeId="1" AcceptedAnswerId="18492" CreationDate="2019-11-18T09:13:18.317" Score="5" ViewCount="6609" Body="&lt;p&gt;Whole civilizations have been buried underground and we have built new landscapes over them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fact that tall buildings and houses are being excavated from under the ground means that we are living very much away from earth's core than the past.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does this mean that we are experiencing less gravity compared to past Since we are further from the earth's core that causes the pull?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note: Parent question&#xA; &lt;a href=&quot;https://earthscience.stackexchange.com/questions/12372/was-the-earths-sea-level-significantly-lower-in-ancient-times&quot;&gt;Was the Earth&amp;#39;s sea-level significantly lower in ancient times?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;asking as separate question as per community suggestion&lt;/p&gt;&#xA;" OwnerUserId="11151" LastActivityDate="2019-11-20T10:05:23.653" Title="Are we experiencing lower level of gravity now compared to past?" Tags="|sea-level|core|gravity|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18492" PostTypeId="2" ParentId="18491" CreationDate="2019-11-18T10:09:07.343" Score="19" Body="&lt;p&gt;Earth's radius is about 6400 kilometres. That's 6400000 metres. Let's say that you have a mound 20 metres high, burying an older settlement. Your new &quot;radius&quot; is now 6400020 metres.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's say that &lt;span class=&quot;math-container&quot;&gt;$g = 9.8\ \rm m/s^2$&lt;/span&gt; at 6400, your new gravity will be &lt;span class=&quot;math-container&quot;&gt;$g = 9.799939\ \rm m/s^2$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clearly, this is hardly &quot;lower level of gravity&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To make this even less significant, the 20 metres of extra dirt underneath you have their own contribution to the gravity. Even though the overall mass of the Earth is the same, local mass variations cause gravity anomalies. Not much, but &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; changes by a bit. So adding more dirt directly underneath you will increase &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt;, counteracting the fact that you're 20 metres farther away from the centre.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2019-11-20T10:05:23.653" LastActivityDate="2019-11-20T10:05:23.653" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18493" PostTypeId="2" ParentId="18491" CreationDate="2019-11-18T10:31:39.993" Score="3" Body="&lt;p&gt;The whole mass of the Earth, mantle, crust, atmosphere and sea, contributes to the Earth's gravitational field, not just the core. Unless you want to split hairs, the Earth's gravity is the same now as it always was. In case you do want to split hairs, the Earth collects a substantial amount of space dust, meteorites and cosmic debris every year, but no one knows exactly how much except that compared to the total mass of the Earth the amount is negligible. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Estimates of annual accumulation vary tremendously, and leave out the contribution of mega-meteorites and asteroid impacts because they are not annual events. Remember that for every major impact on land, two hit the sea and are therefore not recorded. This accumulation increases the mass of the Earth and therefore its gravitational field, but it is balanced by loss of gases, mostly hydrogen, from the upper atmosphere. It is controversial whether losses exceed gains, but it is my view that when you take into consideration the contribution of major impacts, gains marginally exceed losses. Therefore the gravitational field is gradually increasing by an infinitesimal and unmeasurable amount as time goes by. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for whether sea level was lower in ancient times, yes it was, but it depends on which ancient time you are referring to. In warmer times melt water from glaciers raised sea level, while in ice ages evaporation and precipitation lowered sea level and increased the ice sheet on land.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-18T10:31:39.993" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="18495" PostTypeId="1" AcceptedAnswerId="18499" CreationDate="2019-11-18T16:47:23.280" Score="1" ViewCount="58" Body="&lt;p&gt;I am planning to go for organic farming and I would like to utilize available weeds as fertilizers with either anaerobic or aerobic digestion. I understand that during the aerobic process (composting), nitrogen, phosphorous and potassium contained within the feed-stock may be converted to nitrate, phosphate and sulfate. I wanted to know what happens to these three components during the anaerobic process? Which process is better in the farming domain, ignoring methane gas availability in the case of anaerobic process.&lt;/p&gt;&#xA;" OwnerUserId="18220" LastEditorUserId="2470" LastEditDate="2020-01-04T19:19:06.993" LastActivityDate="2020-01-04T19:19:06.993" Title="The state of Nitrogen, Phosphorous and Potassium during Anaerobic Digession" Tags="|soil-science|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18497" PostTypeId="1" CreationDate="2019-11-18T17:23:40.483" Score="4" ViewCount="252" Body="&lt;p&gt;I'm diving into data science and I'm looking for a complete database of minerals.  I downloaded the csv file from &lt;a href=&quot;http://rruff.info/ima/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://rruff.info/ima/&lt;/a&gt; . It contains 5516 lines of data but it does not have images or urls. Does anyone know if there is a database of minerals with images? I'd like to find it to train a neural network.&lt;/p&gt;&#xA;" OwnerUserId="18340" LastEditorUserId="22648" LastEditDate="2021-06-01T09:58:30.950" LastActivityDate="2021-06-01T09:58:30.950" Title="Database of mineral with images for a neural network application" Tags="|minerals|database|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18498" PostTypeId="2" ParentId="18491" CreationDate="2019-11-18T18:19:17.383" Score="5" Body="&lt;p&gt;To address your original concern, no, the fact that there are buildings underground does NOT mean that the surface of the earth is higher than in the past.  What is actually happening is that these buildings are &lt;em&gt;subsiding&lt;/em&gt; into the ground.  How? Believe it or not, earthworms.  Worms were once constantly tunneling through the soil underneath ancient buildings, 'eating' the organic material in the soil, compacting the residue in their digestive tracts, and leaving behind tunnels, i.e open space.  When enough space opened up under the buildings, the soil was no longer strong enough to hold them up, and so they sank, maybe a few millimeters a year.  This got repeated steadily over many millennia, so the buildings sank and were buried.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additional causes of burial: Many buildings were built next to rivers, i.e near the bottom of flood plains, and repeated flooding built up cover; people often rebuild over existing sites, and their comings and goings track in new dirt; etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Correction: Actually, although the surface of the Earth -as a whole- hasn't risen appreciably, thanks to geologic forces there are some &lt;em&gt;regions&lt;/em&gt; where the surface has risen relatively recently (while other regions have gotten lower).  Example: Much of North America has risen in recent millenia due to the tectonic plates rebounding after shedding the weight of melted glaciers.&lt;/p&gt;&#xA;" OwnerUserId="18344" LastActivityDate="2019-11-18T18:19:17.383" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18499" PostTypeId="2" ParentId="18495" CreationDate="2019-11-18T18:41:06.740" Score="1" Body="&lt;p&gt;You're the man who grows coconuts and had a small problem with mimosa plants which you now intend to compost. Don't forget that coconut fronds blown down by the wind and any other waste products from the palms can all go into your compost. In England, earthworms are highly valued in the compost heap, as they help the vegetation break down more efficiently, but I'm not sure how available worms are in Mangalore. If you have a machine that can chop your mimosa cuttings into tiny pieces, that will also help them to compost. Some of the nitrate produced by their roots will find its way to your coconut palms if they are nearby.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, there will be nitrate, phosphate and sulphate in your compost, especially nitrate manufactured by the roots of your mimosa plants. Anaerobic composting still leaves nitrates, phosphates etc in the final product, but also creates methane, which is a very potent greenhouse gas best not released into the atmosphere. The compost also requires an airtight container, so your worms would be suffocated. If your compost is of sufficient quantity to make it worth while, you could tap off the methane and use it as a fuel for cooking. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think the aerobic process would be best suited to your needs, therefore your compost heap will need to be well aerated. Make a bed of twigs to  build your compost heap on, and that will let air in underneath. You will also need to turn the compost over occasionally to let more air in. Aerobic composting does not produce methane. If you see a thriving population of worms in your compost, things are going well.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-18T18:41:06.740" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18501" PostTypeId="2" ParentId="18497" CreationDate="2019-11-18T19:25:24.930" Score="4" Body="&lt;p&gt;First of all rruff.info is an excelent site done by chemists to take data quickly, and you can totally trust the source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second, for images, most of the listed +5000 species are not shown in nature, and you cannot have pictures of all of them. You will only find on the net pictures from common minerals on nature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Third it depends if your work is gonna be published or not, as you would need permission or CC licensed images if so.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Copyrigthed database of pictures and data:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.webmineral.com/danaclass.shtml#.XdPTpdVKjcc&quot; rel=&quot;nofollow noreferrer&quot;&gt;Webmineral&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.mindat.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mindat.org&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Mindat can share with you their data, and &lt;a href=&quot;https://www.mindat.org/copyrights.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;they are going soon to open them on CC format with an API, but the pictures they have belong to each author and many of them are copyrigthed&lt;/a&gt; (and gonna stay copyrigthed if they open data, you would need to ask permission individually for each picture).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;CC license pictures:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I wondered how to obtain pictures from common minerals on CC license because I am writing a mineral app and my choise was Dr Lavinsky collection uploaded to wikipedia from his mineral shop &lt;a href=&quot;https://www.irocks.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;iRocks.com&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At his website they have plentifull of high quality well described pictures of common minerals you can maybe download with a script making GET petitions, and you can ask them for permission, even for the pictures that are not uploaded to the wiki. I did it myself for my mineral guide and they just ask me to quote iRocks.com; they are very fair people. Aparently they are happy to share if you quote his shop.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At Wikipedia you can find on CC license &gt;2000 pictures uploaded from mindat.org, and &gt;5000 uploaded from iRocks.com&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You have the &lt;a href=&quot;https://commons.wikimedia.org/w/index.php?title=Category:Minerals&amp;amp;subcatuntil=Axinite-%28Mn%29#mw-subcategories&quot; rel=&quot;nofollow noreferrer&quot;&gt;complete list of minerals with picture on Wikimedia Commons&lt;/a&gt; where to start to collect the data. I don't know if you could somehow extract all the images url using GET petitions with code. Myself I only took the iRocks pictures because my guide covered only 180 minerals, the descriptions Dr Lavinsky provides are valuable (&lt;a href=&quot;https://www.irocks.com/minerals/specimen/47722&quot; rel=&quot;nofollow noreferrer&quot;&gt;example&lt;/a&gt;), and then I only needed to quote one author (I ended by taking them directly from iRocks and link on my work to each piece on his shop, they got very happy about that, they answered my mail with &quot;many thanks&quot;).&lt;/p&gt;&#xA;" OwnerDisplayName="user18261" LastEditorDisplayName="user18261" LastEditDate="2019-11-19T13:20:28.503" LastActivityDate="2019-11-19T13:20:28.503" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18502" PostTypeId="1" CreationDate="2019-11-18T21:26:29.510" Score="1" ViewCount="103" Body="&lt;p&gt;Are weather forecasts such as on weather.com or other apps continuously updated for each location and updated by an operator or is it just a computer automatically updating the forecast?&lt;/p&gt;&#xA;" OwnerUserId="17923" LastEditorUserId="1411" LastEditDate="2019-11-19T01:02:35.360" LastActivityDate="2019-11-20T09:57:35.183" Title="Weather Forecasts" Tags="|weather-forecasting|weather-satellites|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18503" PostTypeId="1" CreationDate="2019-11-19T00:42:48.853" Score="1" ViewCount="86" Body="&lt;p&gt;Since 1950 surface temperatures have risen significantly even though the total radiant energy from the Sun has been decreasing over this same period. To the best of my current understanding as long as these two graphs are accurate this makes it game over for the climate change deniers.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Is there any climate science explanation for the significant increase in surface temperatures corresponding to a decrease in radiant energy besides severe anthropogenic heating?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://climate.nasa.gov/faq/14/is-the-sun-causing-global-warming/?fbclid=IwAR2d6RW0KpLXRifAU4hZPbEjXVLnRcLRshw233gGJW--47tl0NfdY7JMTyk&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://climate.nasa.gov/faq/14/is-the-sun-causing-global-warming/?fbclid=IwAR2d6RW0KpLXRifAU4hZPbEjXVLnRcLRshw233gGJW--47tl0NfdY7JMTyk&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xoBQ7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xoBQ7.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17970" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-11-19T00:42:48.853" Title="Is there any climate science explanation for this graph besides severe anthropogenic heating?" Tags="|climate-change|" AnswerCount="0" CommentCount="13" ClosedDate="2019-11-21T08:32:58.883" ContentLicense="CC BY-SA 4.0" />
  <row Id="18505" PostTypeId="2" ParentId="18497" CreationDate="2019-11-19T01:53:39.477" Score="0" Body="&lt;p&gt;I think &lt;a href=&quot;http://www.mindat.org&quot; rel=&quot;nofollow noreferrer&quot;&gt;www.mindat.org&lt;/a&gt; has what you are looking for but I don't know how easy it is to perform you own queries of the underlying database.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2019-11-19T01:53:39.477" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18506" PostTypeId="1" CreationDate="2019-11-19T11:40:20.090" Score="4" ViewCount="21" Body="&lt;p&gt;For my thesis, the lecturer proposed to make a &quot;sensitivity analysis&quot; with a 2D surface model connected with a 1D drainage Network model for a storm rain event. However, I'm having problems to figure out what that means or could mean. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My study area is about 8km² large. I have a high resolution DEM with 1m grids. I have a weather station about 1-2km from my catchment which measured the precipitation of the storm event in mm/h for every 5min, I have a detailed and current land use map of the area, I have a station which measured the water level at the river and Information on the drainage network. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, I understand that sensitivity analysis basically means to figure out how the model results change when I modify the input data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I guess I could look at precipitation variablility. I could check how the model reacts to diffrent heterogeneous rainfall distributions or diffrent rain intensities. But is that a good approach? The study area seems small, and there are no hills that could cause big differences to the weather station. There shouldn't be a noticable diffrent rain intensity and spatial distribution shouldn't it? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I could change the DEM and see what happens but why would anyone use a coarser DEM if a high resolution DEM is available? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can play around with the roughness but landuse data is very good and using the manning strickler tables for roughness are standard. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I feel like nothing makes sense. Does anyone have some advice on what kind of sensitivity analysis I could do? &lt;/p&gt;&#xA;" OwnerUserId="18169" LastActivityDate="2019-11-19T11:40:20.090" Title="what is a sensitivity analysis in heavy rain 2D surface / 1D drainage network models" Tags="|hydrology|models|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18507" PostTypeId="2" ParentId="18502" CreationDate="2019-11-19T15:41:56.380" Score="0" Body="&lt;p&gt;Given the proprietary nature of that information, I don't think that can really be answered. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But my best guess is that it may be updated by a computer, and adjusted by a meteorologist to better align with observations. There is probably some algorithm that mediates between the two.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2019-11-19T15:41:56.380" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18508" PostTypeId="1" CreationDate="2019-11-19T16:10:47.767" Score="1" ViewCount="32" Body="&lt;p&gt;I would like to determine, specifically, azimuth and elevation data for any given location on the surface of the earth relative to another location on the surface of the earth (for my purposes, the latter will be London, UK). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Data and APIs are readily available for certain celestial objects, but I haven't had any luck finding data as required.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone enlighten me as to a method for calculating such data?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many thanks.&lt;/p&gt;&#xA;" OwnerUserId="18359" LastEditorUserId="18359" LastEditDate="2019-11-19T18:09:01.933" LastActivityDate="2019-11-19T18:09:01.933" Title="Determining Horizontal Coordinate System data (azimuth, altitude) for geographic locations" Tags="|open-data|coordinate-system|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18509" PostTypeId="1" AcceptedAnswerId="19084" CreationDate="2019-11-19T16:28:16.463" Score="1" ViewCount="195" Body="&lt;p&gt;I have a lat lon - 23.14, 83.14 and I need to download the NASA Earth Exchange Global Daily Downscaled Projections (NEX-GDDP) data from the below website only for this lat lon. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://dataserver.nccs.nasa.gov/thredds/catalog/bypass/NEX-GDDP/catalog.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://dataserver.nccs.nasa.gov/thredds/catalog/bypass/NEX-GDDP/catalog.html&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a tool/website/script that I can use to download the data 2040 - 2060 ? Would someone be willing to show me how to do this?&lt;/p&gt;&#xA;" OwnerUserId="13078" LastEditorDisplayName="user1066" LastEditDate="2019-11-20T07:33:25.953" LastActivityDate="2020-01-28T08:39:01.793" Title="download NASA Earth Exchange Global Daily Downscaled Projections for single lat lon" Tags="|climate-change|gis|nasa|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18510" PostTypeId="2" ParentId="18453" CreationDate="2019-11-19T17:02:53.457" Score="2" Body="&lt;p&gt;TL;DR: It is not a problem, it is a feature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As it was pointed in the comments, 1000 hPa over land (and sometimes over ocean) is below the surface. MERRA is just fair enough not to put any values where they do not exist. Other reanalyses use some procedure to fill the gaps and make fields without holes. The procedure is reanalysis specific, and, can ususlly be found in corresponding technical manual. The gap-filled fields have little physical meaning anyway.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the gaps do not make sense for you, 1000-hPa wind is, probably, not the field you need. E.g. if you are after near-surface wind, 10-m wind is more appropriate quantity.&lt;/p&gt;&#xA;" OwnerUserId="18363" LastActivityDate="2019-11-19T17:02:53.457" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18511" PostTypeId="1" CreationDate="2019-11-19T19:26:36.057" Score="1" ViewCount="204" Body="&lt;p&gt;I began to do the best that I could to boil the key facts down to the most basic essence of proving significant anthropogenic climate change:  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(1) It is a verified fact that since 1959 &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; increased 98 PPM which is 126 times faster than the next fastest increase of at least 90 PPM in the prior 800,000 years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) It is a verified fact that &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; is currently 37% higher that its prior 800,000 year high value of 298 PPM.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(3) It is a verified fact that global temperatures have increased  about 0.75C since 1970. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(4) It is a verified fact that the only reason the Earth is much warmer than the Moon is the greenhouse effect of greenhouse gases. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(5) It is a verified fact that a significant increases in greenhouses gases cause a corresponding significant increases in global temperatures. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It does seem to be the case that within the premise that all of the above facts are true that significant anthropogenic climate change is proven. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only pushback that I have gotten from global heating deniers is that they simply do not believe the temperature record. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;By what objectively correct process could we determine the truth about the actual severity of anthropogenic climate change?&lt;/strong&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;There are two key goals of the above question:&lt;/strong&gt; &lt;br&gt;&#xA;(1) To make sure that the above five points sufficiently prove AGH.&lt;br&gt;&#xA;(2) To find very succinct and compelling ways to validate these five points.&lt;br&gt;&lt;/p&gt;&#xA;" OwnerUserId="17970" LastEditorUserId="2470" LastEditDate="2020-01-04T19:14:22.450" LastActivityDate="2020-01-04T19:14:22.450" Title="By what objectively correct process could we determine the truth about the actual severity of anthropogenic climate change?" Tags="|climate-change|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18512" PostTypeId="1" CreationDate="2019-11-20T00:13:18.543" Score="3" ViewCount="2852" Body="&lt;p&gt;Could you tell me what the  WRF's vertical coordinate system is? Sigma or eta?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the User WRF Guide document, uses a terrain-following hydrostatic pressure coordinate while the WRF namelist has eta level. Are both of them same?&lt;/p&gt;&#xA;" OwnerUserId="14589" LastActivityDate="2019-11-20T09:29:48.573" Title="Does WRF simulation use sigma or eta vertical coordinate system?" Tags="|meteorology|climate-models|wrf|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18514" PostTypeId="2" ParentId="18512" CreationDate="2019-11-20T09:29:48.573" Score="5" Body="&lt;p&gt;WRF is using the sigma (terrain-following) vertical coordinate. However, as @gansub has already referred, in WRF V3.9 you can now select a hybrid sigma-pressure vertical coordinate. The advantage of this is that the coordinate is terrain-following near the surface, but it 'converts' to pressure levels at higher levels, which improves the accuracy of the calculation of the pressure gradient. Over very steep terrain the sigma coordinate extends this steepness throughout the atmosphere which is not very ideal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For sigma coordinates, you still define the eta-levels. (Note that it sigma coordinates is just a normalisation of pressure)&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\sigma = \frac{p-p_t}{p_s-p_t}&#xA;$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; is specified through&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;p=A+Bp_s.&#xA;$$&lt;/span&gt;&#xA;It has been a few years since I played around with WRF, so I don't know how this change affects computational efficiency. If you get any results on this that will be interesting to hear.&lt;/p&gt;&#xA;" OwnerUserId="17522" LastActivityDate="2019-11-20T09:29:48.573" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18515" PostTypeId="2" ParentId="18502" CreationDate="2019-11-20T09:57:35.183" Score="1" Body="&lt;p&gt;Your question is extremely broad and it would be comprehensive to answer in detail.&#xA;How it is done varies from one application to another. But in general, all weather forecasts come from a numerical prediction which is based on an analysis. The analysis is created by combining a prior (the previous forecast) with observations. There are many ways this can be implemented in practice. If you are interested you can start by looking up sequential assimilation and variational assimilation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some applications apply a Kalman Filter (a recursive method) to update a forecast when new observations come in, but this is probably becoming less relevant as models start to be run in rapid update cycles, e.g. a new analysis (and forecast) every 10-60 minutes. The weather model itself is a big subject in its own, with numerical approximations, optimisation and parameterisations.&lt;/p&gt;&#xA;" OwnerUserId="17522" LastActivityDate="2019-11-20T09:57:35.183" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18516" PostTypeId="2" ParentId="18361" CreationDate="2019-11-20T14:44:31.597" Score="1" Body="&lt;p&gt;If there is no direct function available, you can create a Trace/Stream object yourself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The solution I use (example for one time series) is:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;read the Ascii file into a numpy array&lt;/li&gt;&#xA;&lt;li&gt;trace = obspy.core.Trace(data=&lt;em&gt;numpy array&lt;/em&gt;, header=&lt;em&gt;header dictionnary of your choice&lt;/em&gt;)&lt;/li&gt;&#xA;&lt;li&gt;stream = obspy.core.Stream(traces=[trace])&lt;/li&gt;&#xA;&lt;li&gt;stream.plot()&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="4551" LastActivityDate="2019-11-20T14:44:31.597" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18517" PostTypeId="2" ParentId="15711" CreationDate="2019-11-20T23:25:37.557" Score="2" Body="&lt;p&gt;October 1st is mostly used, but it varies from country to country. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Norway, the hydrological year start on September 1st, mostly because groundwater levels are at their lowest. At that time of the year, all snow in the mountains has melted, and it is before temperatures fall and the autumn rain settles in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is probably better to use October 1st than the calendar year. You probably want to avoid starting new periods in the middle of a snow season (or a heavy rain season near equator). If you are only dealing with data from one country, it is perhaps best to use the local standard.&lt;/p&gt;&#xA;" OwnerUserId="18375" LastEditorUserId="18375" LastEditDate="2019-11-21T00:20:21.657" LastActivityDate="2019-11-21T00:20:21.657" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18518" PostTypeId="1" CreationDate="2019-11-20T23:48:44.417" Score="2" ViewCount="352" Body="&lt;p&gt;The jaguar is a close relative of the Asiatic leopard and must have had a common ancestor within the last 5 million years. The South American tapir is obviously closely related to the Malayan tapir and must also have had a common ancestor within he last 5 million years. How did the leopard and tapir, typically tropical species, get from Asia to South America?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An obvious route would be the land route via the Bering Straits and the southern shore of Alaska which was used by humans about 15,000 years ago when the Ice Age had lowered sea level, but both animals are tropical and it is hard to believe they would have chosen such an icy route. The jaguar and tapir have in any case been separated from their Asiatic relatives for a lot longer than 15,000 years. I am wondering whether they could have arrived via a different route from the one chosen by the earliest human inhabitants of the Americas. Can anyone throw any light on this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Continental drift played a part in isolating Old World monkeys from South American monkeys and setting Australia adrift carrying only marsupials, so is there a possibility that when Africa and Amazonia were closer together, immigration from Africa could have taken place, bearing in mind that there were times when sea levels were much lower?&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-11-21T12:39:06.003" LastActivityDate="2019-11-21T19:01:18.307" Title="Migration Routes for Animals from Asia to America" Tags="|plate-tectonics|sea-level|ice-age|evolution|" AnswerCount="1" CommentCount="15" ClosedDate="2019-11-22T05:43:42.090" ContentLicense="CC BY-SA 4.0" />
  <row Id="18519" PostTypeId="1" CreationDate="2019-11-21T03:01:07.220" Score="3" ViewCount="69" Body="&lt;p&gt;This was taken about November 18 in southern Arizona, USA. I’ve never seen any clouds like this before. Is it natural or caused by some airplane? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/24yGp.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/24yGp.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7100" LastActivityDate="2019-11-21T03:01:07.220" Title="What causes this cloud formation?" Tags="|clouds|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18521" PostTypeId="1" CreationDate="2019-11-21T03:31:10.493" Score="1" ViewCount="55" Body="&lt;p&gt;Could you give me some basic understanding of how to analyze the atmospheric vertical motion? &#xA;For example, could you list some basic metrics to diagnose the vertical motion? Like divergence, vertical velocity (Omega). I got these two proxies from the published papers. Are there other common metrics to analyze vertical motion? &#xA;I am a hydrological guy and have not so much meteorological background.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you so much.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;BTW, I am sorry for my too general question, but I just wanna some common metrics to do vertical motion analysis. My research focus on extreme precipitation.&lt;/p&gt;&#xA;" OwnerUserId="14589" LastEditorUserId="14589" LastEditDate="2019-11-21T04:42:29.703" LastActivityDate="2019-11-21T07:26:48.780" Title="List some common metrics to analyze the atmospheric vertical motion?" Tags="|meteorology|climate-models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18522" PostTypeId="2" ParentId="18521" CreationDate="2019-11-21T07:26:48.780" Score="1" Body="&lt;p&gt;First of all, I am unsure if your question relates to Numerical Weather Prediction (NWP) or field-experiments. I would say divergence is one of the best variables to look at since vertical motion is both difficult to measure and to model. Also, some nowcasting models which includes a nudging method to increase precipitation intensity in the model, based on the observed intensity does this by nudging the divergence field directly, to generate more or less vertical motion.&lt;/p&gt;&#xA;" OwnerUserId="17522" LastActivityDate="2019-11-21T07:26:48.780" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18523" PostTypeId="1" CreationDate="2019-11-21T16:25:18.070" Score="1" ViewCount="562" Body="&lt;p&gt;I planned to use the ERA5 Potential evapotranspiration data for drought analsysis (SPEI), however values are presented in negative number. Of course I understand the logic for presenting PET negative. But, I want to convert it into positive and I should all the PET data positive. I knowledge those who help me to change the negative value in to positive. I am using cdo for data processing. Thank you!&#xA;Mekonnen Adnew Degefu  &lt;/p&gt;&#xA;" OwnerUserId="18380" LastActivityDate="2019-11-28T18:32:26.907" Title="How can I convert the negative values of the ERA5 PET data into positive?" Tags="|climate|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18524" PostTypeId="1" CreationDate="2019-11-21T17:30:52.673" Score="4" ViewCount="156" Body="&lt;p&gt;I am developing a &lt;a href=&quot;https://github.com/makeyourownmaker/ParametricWeatherModel&quot; rel=&quot;nofollow noreferrer&quot;&gt;simple parameterisation scheme script&lt;/a&gt; to predict surface temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The script calculates six heat fluxes including sensible heat flux using a resistance to heat flux parameter.  The literature I've checked describes resistance to heat flux as taking values greater than 0 and having units of &lt;span class=&quot;math-container&quot;&gt;$\rm{s} ~ \rm{m}^{-1}$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sensible heat flux is calculated as,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$Q_H = \frac{\rho c_p \Delta T}{r_H}$&lt;/span&gt;,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; is air density, &lt;span class=&quot;math-container&quot;&gt;$c_p$&lt;/span&gt; is specific heat at constant pressure, &lt;span class=&quot;math-container&quot;&gt;$\Delta T$&lt;/span&gt; is change in temperature between the ground layer and the surface layer and &lt;span class=&quot;math-container&quot;&gt;$r_H$&lt;/span&gt; is resistance to heat flux.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is a reasonable range of values for resistance to heat flux in meteorology?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A single range would be useful but ranges for urban, agricultural, forest, desert, mountain and marine areas would be preferable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally, I'm open to alternative suggestions for calculating sensible heat flux but using x % of solar radiation feels overly simple.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;For context&lt;/strong&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My script is currently predicting day time temperatures which are probably too low and night time temperatures which are probably too high.  I'd like to verify that the sensible heat flux calculation is the cause but I need to know what reasonable values for resistance to heat flux are.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is based on the second chapter of &lt;a href=&quot;https://doi.org/10.1017/CBO9780511812590&quot; rel=&quot;nofollow noreferrer&quot;&gt;David Stensrud's Parameterisation Schemes book&lt;/a&gt; and is inspired by Luke Madaus' blog post, &lt;a href=&quot;http://lukemweather.blogspot.com/2011/08/digging-into-simple-weather-model.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Digging into a &quot;simple&quot; weather model&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="18379" LastEditorUserId="18379" LastEditDate="2019-11-24T13:17:51.633" LastActivityDate="2020-12-22T23:06:35.647" Title="What is a reasonable range of values for resistance to heat flux?" Tags="|meteorology|temperature|weather-forecasting|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18525" PostTypeId="2" ParentId="18518" CreationDate="2019-11-21T19:01:18.307" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The jaguar is a close relative of the Asiatic leopard and must have had a common ancestor within the last 5 million years. The South American tapir is obviously closely related to the Malayan tapir and must also have had a common ancestor within he last 5 million years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;While the first statement is more or less correct, the latter is not. The Asian and American branches of the tapirs split about 25 million years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding migration routes, felines have migrated back and forth between Asia and North America many times in the last eight million years or so. The ancestors of Tapirs apparently migrated back and forth between North America and Europe before 25 million years ago, when the climate was much warmer and the continents had slightly different shapes.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... is there a possibility that when Africa and Amazonia were closer together, immigration from Africa could have taken place?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Regarding South America, there were very few placental mammals in South America until about 3 million years ago, when the Isthmus of Panama formed. The age of the Isthmus is debated. The sudden appearance of placental mammal fossils about 2.7 million years ago in South America, including jaguars and tapirs, is not. South America's jaguars and tapirs migrated to South America via North America rather than Africa.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2019-11-21T19:01:18.307" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18526" PostTypeId="1" AcceptedAnswerId="18530" CreationDate="2019-11-21T19:36:22.713" Score="6" ViewCount="115" Body="&lt;p&gt;During one of my walks through the city streets, I noticed that some basalt blocks that make up the sidewalk have in their surface some very curious natural patterns:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DlBWh.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DlBWh.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TFuUE.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TFuUE.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/udcDP.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/udcDP.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1lnff.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1lnff.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The photos above was taken at the &lt;a href=&quot;https://en.wikipedia.org/wiki/Porto_Alegre&quot; rel=&quot;noreferrer&quot;&gt;Porto Alegre&lt;/a&gt; city, Brazil. (Coordinates: &lt;a href=&quot;https://www.google.com/maps/place/30%C2%B001&amp;#39;59.0&amp;quot;S+51%C2%B013&amp;#39;48.0&amp;quot;W&quot; rel=&quot;noreferrer&quot;&gt;30°01′59″S 51°13′48″W&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are these fractal-like patterns? How and when are they formed? Is it some kind of organic formation? Is it living being or some kind of fossil?&lt;/p&gt;&#xA;" OwnerUserId="18381" LastEditorUserId="18381" LastEditDate="2019-11-21T21:47:54.240" LastActivityDate="2019-11-22T07:52:12.523" Title="Curious natural patterns on the surface of basalt blocks that make up the sidewalk" Tags="|rocks|fossils|igneous|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18527" PostTypeId="2" ParentId="18526" CreationDate="2019-11-21T19:46:52.647" Score="1" Body="&lt;p&gt;They are quite pretty, but they are not fossils. They remind me of the patterns that frost sometimes makes on window panes. A similar process is at work here, though with mineral bearing water infiltration rather than frost being the cause. The water infiltration deposits crystals in the rock.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-11-21T19:56:41.430" LastActivityDate="2019-11-21T19:56:41.430" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18528" PostTypeId="1" CreationDate="2019-11-21T23:02:49.010" Score="1" ViewCount="130" Body="&lt;p&gt;The question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/10500/is-there-a-lake-whose-sole-source-of-water-is-rain-and-has-a-hole-at-the-bottom&quot;&gt;Is there a lake whose sole source of water is rain and has a hole at the bottom draining it?&lt;/a&gt; doesn't have an answer that answers my question. Also, it has a mistake in it. According to the first comment under the body of the question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/18451/is-oregon-lake-extremely-pure-water-if-so-why&quot;&gt;Is Oregon lake extremely pure water? If so, why?&lt;/a&gt;, the lake in the video &lt;a href=&quot;https://www.youtube.com/watch?v=JRhMegxuT5w&quot; rel=&quot;nofollow noreferrer&quot;&gt;Clear Lake, Oregon&lt;/a&gt; and the lake in the video &lt;a href=&quot;https://www.youtube.com/watch?v=XAMLGB0hUmk&quot; rel=&quot;nofollow noreferrer&quot;&gt;Adventure Oregon - Lost Lake draining into a giant hole&lt;/a&gt; aren't the same lake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://en.wikipedia.org/w/index.php?title=Pingualuit_crater&amp;amp;oldid=927258451&quot; rel=&quot;nofollow noreferrer&quot;&gt;this revision&lt;/a&gt; the Wikipedia article Pingualuit crater which is also the current revision, &quot;The lake also holds some of the purest fresh water in the world, with a salinity level of less than 3 ppm (the salinity level of the Great Lakes is 500 ppm).&quot; I assume that all solutes except air have an extremely low concentration. I also assume that the dissolved air doesn't have a higher concentration at lower depths despite the higher pressure there because there are no compressed air pockets down there to dissolve into the water and is saturated only at the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is it true that all the nongaseous solutes have a concentration by volume that's almost as low as that of salt? If not, approximately what is the concentration of the nongaseous solute with the highest concentration and what is that solute? Could the cause of the high purity be that Pingualuit crater is on high ground so the water is constantly soaking into the ground below draining solutes with it and getting replaced by rain water because there are no outlets to Pingualuit crater?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I realize that probably nothing is totally insoluble in water and so the surrounding rock probably dissolves to some extent.&lt;/p&gt;&#xA;" OwnerUserId="4846" LastEditorUserId="4846" LastEditDate="2019-11-27T02:12:53.587" LastActivityDate="2019-11-27T02:12:53.587" Title="Why is the water in Pingualuit crater so pure?" Tags="|lakes|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18529" PostTypeId="1" CreationDate="2019-11-21T23:25:29.740" Score="3" ViewCount="1898" Body="&lt;p&gt;I've just started teaching 9th grade Earth science and my students and I have noticed something about P and S wave depth vs velocity graphs. In the typical graph, &#xA;eg: &lt;a href=&quot;https://www.researchgate.net/figure/Earths-P-wave-velocity-S-wave-velocity-and-density-profiles-as-a-function-of-depth_fig8_280835886&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/figure/Earths-P-wave-velocity-S-wave-velocity-and-density-profiles-as-a-function-of-depth_fig8_280835886&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With the p wave's velocity plotted from a depth of 0 km to a depth of 6371 km it shows the p wave velocity reaching about 14 km/sec by the time it reaches the bottom of the mantle.  Then of course it drops precipitously through the mantle/outer core boundary. However, even when the wave reaches the inner core, it's velocity never gets close to that 14 km/sec speed, it's speeds in the inner/outer core range only from 8 to 12 km/sec even though the core has a much higher density than the mantle. You would expect a much higher wave velocity. &lt;/p&gt;&#xA;" OwnerUserId="18383" LastEditorUserId="14194" LastEditDate="2019-11-22T15:19:15.083" LastActivityDate="2019-11-23T01:41:03.977" Title="Why do P waves have a higher velocity in the lower mantle than in the core even though the core has a much higher density?" Tags="|seismic|waves|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18530" PostTypeId="2" ParentId="18526" CreationDate="2019-11-22T07:52:12.523" Score="7" Body="&lt;p&gt;These are most likely manganese dendrites. It is not a fossil, and not organic. These usually form in cracks in rocks, and most likely this slab was broken along an existing crack.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can read more about it now: &lt;a href=&quot;https://www.mindat.org/min-26645.html&quot; rel=&quot;noreferrer&quot;&gt;https://www.mindat.org/min-26645.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One comment: this is not basalt. Basalt is black. Most likely some form of limestone.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-11-22T07:52:12.523" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18531" PostTypeId="2" ParentId="18523" CreationDate="2019-11-22T09:34:18.647" Score="0" Body="&lt;p&gt;We are missing some information about the ERA5 data. Do you have it in grib2 or netcdf format? Nevertheless, take a look at the &lt;a href=&quot;https://code.mpimet.mpg.de/projects/cdo/embedded/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;documentation&lt;/a&gt;. You can do it with cdo's &lt;code&gt;abs&lt;/code&gt; command. It would be something like this:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cdo expr,absPET=&quot;abs(PET)&quot; -mergetime infile1 infile2 infile3 outputfile&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;which makes a new variable &lt;code&gt;absPET&lt;/code&gt; in the output file. &lt;code&gt;expr&lt;/code&gt; makes it possible to evaluate expressions, like &lt;code&gt;abs()&lt;/code&gt;.&lt;/p&gt;&#xA;" OwnerUserId="17522" LastActivityDate="2019-11-22T09:34:18.647" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18533" PostTypeId="2" ParentId="18523" CreationDate="2019-11-22T13:05:28.170" Score="2" Body="&lt;p&gt;You can multiply all the values by -1&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cdo mulc,-1 infile.nc outfile.nc&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;If you want also to get rid of the condensation data (and, please, note that I am not implying that that is the right thing to do), you can do something like &lt;a href=&quot;https://code.mpimet.mpg.de/boards/1/topics/2484&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cdo setrtoc,0,9999,0 ifile.nc ofile.nc&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Hope this helps&lt;/p&gt;&#xA;" OwnerUserId="8087" LastEditorUserId="8087" LastEditDate="2019-11-28T18:32:26.907" LastActivityDate="2019-11-28T18:32:26.907" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18534" PostTypeId="1" AcceptedAnswerId="18775" CreationDate="2019-11-22T22:10:24.733" Score="5" ViewCount="370" Body="&lt;p&gt;Matter tends to change its volume in response to changes in temperature--or, hot things tend to be expanded. Is the thermal expansion of Earth significant?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is, is it significant when compared against a cooler or perhaps internally-inert Earth?&lt;/p&gt;&#xA;" OwnerUserId="15419" LastEditorUserId="15419" LastEditDate="2019-11-22T22:19:04.420" LastActivityDate="2019-12-24T09:41:39.600" Title="Thermal expansion of Earth" Tags="|geophysics|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18535" PostTypeId="2" ParentId="18534" CreationDate="2019-11-22T23:08:04.490" Score="-1" Body="&lt;p&gt;There is no thermal expansion of the Earth. On the contrary, the Earth is very gradually cooling, and therefore shrinking, but so gradually that the effects are imperceptible and perhaps in the short term unmeasurable. You can see the process at work on Mars, which has over the course of 4.5 billion years lost much of its internal heat owing to its smaller size and greater distance from the sun. The result is that volcanism has ceased and the planet has a much thicker crust, but the core is still molten. Therefore Mars must have shrunk a little, but we don't know exactly how much because we have no precise measurements from four billion years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gravitational flexion ie. tides in the Earths outer regions caused by the moon, as well as decay of radioactive elements in the core and mantle, generate heat which reduces the rate at which the Earth cools. The Earth's loss of heat is so gradual that its interior still won't be completely inert when the sun expands to become a red giant in 5 billion years time. The Earth will then stop cooling and the surface will be scorched and probably melted, but it's nothing to worry about because 5 billion years is an almost unimaginably long time. Humans will have gone to join the dinosaurs billions of years earlier.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-22T23:08:04.490" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18536" PostTypeId="2" ParentId="18529" CreationDate="2019-11-23T01:41:03.977" Score="3" Body="&lt;p&gt;tldr; &lt;strong&gt;Increased density corresponds with decreased P-wave velocity&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The P-wave velocity for an isotropic medium is:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;V_p = \sqrt\frac{K+4/3\mu}{\rho}&#xA;$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$K$&lt;/span&gt; is the Bulk Modulus, &lt;span class=&quot;math-container&quot;&gt;$\mu$&lt;/span&gt; is the shear modulus, and &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; is the density (&lt;a href=&quot;https://en.wikipedia.org/wiki/Elastic_modulus&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Elastic_modulus&lt;/a&gt;, see &lt;span class=&quot;math-container&quot;&gt;$M$&lt;/span&gt; the P-wave modulus). Isotropy just means that the strain on the rock caused by a stress is irrespective of the stress orientation. Examining the equation you can see that &lt;strong&gt;increased density corresponds with decreased velocity&lt;/strong&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the mantle, &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; increases with depth, but the numerator &lt;span class=&quot;math-container&quot;&gt;$K+4/3\mu$&lt;/span&gt; increases faster than the &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt;, so the net effect is an increase in velocity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the &lt;strong&gt;fluid&lt;/strong&gt; outer core, &lt;span class=&quot;math-container&quot;&gt;$\mu = 0$&lt;/span&gt;. This is because fluids do not support shear stresses. Correspondingly, &lt;span class=&quot;math-container&quot;&gt;$V_p$&lt;/span&gt; drops precipitously.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the &lt;strong&gt;solid&lt;/strong&gt; inner core, &lt;span class=&quot;math-container&quot;&gt;$\mu$&lt;/span&gt; is nonzero hence there is a jump in velocity at the inner/outer core boundary. The combination of &lt;span class=&quot;math-container&quot;&gt;$K$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\mu$&lt;/span&gt;, and &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; in the inner core is such that &lt;span class=&quot;math-container&quot;&gt;$V_p$&lt;/span&gt; doesn't exceed the lower mantle values.&lt;/p&gt;&#xA;" OwnerUserId="18386" LastActivityDate="2019-11-23T01:41:03.977" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18537" PostTypeId="1" CreationDate="2019-11-23T03:10:51.543" Score="8" ViewCount="2992" Body="&lt;p&gt;When an oceanic plate goes under a continental plate are the resulting mountains a result of the melting and then rising of the oceanic plate or are the mountains formed by the continental plate being pushed up by the collision with the oceanic plate?&lt;/p&gt;&#xA;" OwnerUserId="12694" LastActivityDate="2020-02-04T19:32:01.697" Title="How does a subduction zone form mountains?" Tags="|plate-tectonics|subduction|mountain-building|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18539" PostTypeId="2" ParentId="18537" CreationDate="2019-11-23T09:28:34.200" Score="5" Body="&lt;p&gt;When the subducted oceanic plate slides beneath the continental crust, it causes crustal thickening and sometimes crustal folding. In addition to this, rising plumes of magma are created when the oceanic plate is forced down into the mantle. These are all orogenic (mountain building) processes. We also have mountains built by volcanoes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The friction created by the subducted plate scraping the bottom of the plate above as it is being forced into the hot mantle, plus the fact that it carries water with it, causes partial melting of the plate and the rising of magma plumes, which also have a lifting effect. Water mixing with the magma makes it more fluid and more easily melted. These plumes often force their way through the upper plate and erupt as volcanoes, which is why volcanic arcs are created near subduction zones. The classic example of volcanic arcs is found around the Pacific rim, where subduction zones abound.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-23T09:28:34.200" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18540" PostTypeId="2" ParentId="18511" CreationDate="2019-11-23T13:05:09.330" Score="1" Body="&lt;p&gt;We have reasonably good observations of the present.  We have moderately decent observations of the past (with larger uncertainties the further back we go).  Unfortunately, we have no observations at all of the future.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are fundamentally only two ways to know about future impacts:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;We can wait.  20 years, 50 years, 300 years.  We will know for sure, but it will be far too late to act on the knowledge to prevent the worst consequences.&lt;/li&gt;&#xA;&lt;li&gt;We can model the impacts.  All models are wrong, but some are useful.  There is no &quot;objectively correct process to determine the truth about the actual severity&quot;, because &quot;actual severity&quot; is not an objectively defined quantity.  However, we can model the impacts on biodiversity loss, sea level rise, desertification, food security, economic losses, and other measurable quantities that we care about.  From a strictly mathematical point of view, we can never be 100% sure.  However, if we are 99% sure of net impacts that most people would consider to be very bad indeed unless we act, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Precautionary_principle&quot; rel=&quot;nofollow noreferrer&quot;&gt;precautionary principle&lt;/a&gt; suggests acting is the wisest thing to do.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/dAotc.jpg&quot; alt=&quot;comic showing a list of advantages of acting, with a critical audience member asking: What if it&amp;#39;s a big hoax and we create a better world for nothing?&quot;&gt;&lt;br&gt;&#xA;&lt;em&gt;Source: USA Today, but has been published in many newspapers.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2019-11-23T13:18:23.930" LastActivityDate="2019-11-23T13:18:23.930" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18541" PostTypeId="1" CreationDate="2019-11-23T16:41:22.753" Score="0" ViewCount="267" Body="&lt;p&gt;Because the arctic temperature record would probably not require any of the climategate urban heat island adjustments it would seem to definitively sustain that global temperatures are significantly rising. This would seem to form the most unequivocal and verifiable proof that rhetoric to the contrary is simply false.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;List of Arctic weather stations that are the source of the Arctic temperature record:&lt;/strong&gt;&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_research_stations_in_the_Arctic&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/List_of_research_stations_in_the_Arctic&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://berkeleyearth.org/wp-content/uploads/2018/01/Arctic2017.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://berkeleyearth.org/wp-content/uploads/2018/01/Arctic2017.png&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pxu7u.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pxu7u.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17970" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-11-23T20:34:05.727" Title="Could the recent temperature anomalies in the arctic be used as a proxy measure of global heating?" Tags="|climate-change|" AnswerCount="1" CommentCount="13" ContentLicense="CC BY-SA 4.0" />
  <row Id="18542" PostTypeId="1" AcceptedAnswerId="18544" CreationDate="2019-11-23T17:22:02.400" Score="4" ViewCount="153" Body="&lt;p&gt;I would like to know what would happen with the atmosphere of Venus when it gets tidally locked, i.e. when one side would perpetually face the Sun.&lt;br&gt;&#xA;Probably a thermal low would be at the subsolar region then.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the surface Venus has an atmospheric pressure of &lt;strong&gt;92 atm.&lt;/strong&gt; and a temperature of &lt;strong&gt;462&lt;span class=&quot;math-container&quot;&gt;$⁰$&lt;/span&gt; C.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there General Circulation Models or Global Climate Models that can handle such input parameters ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If so, are there GCM users (groups, universities etc.) who could run a tidally locked Venus simulation ?&lt;/p&gt;&#xA;" OwnerUserId="12903" LastEditorUserId="12903" LastEditDate="2019-11-23T22:16:43.263" LastActivityDate="2019-11-23T22:16:43.263" Title="Are there General Circulation Models that can simulate the atmosphere of Venus?" Tags="|climate-models|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="18544" PostTypeId="2" ParentId="18542" CreationDate="2019-11-23T19:44:06.217" Score="5" Body="&lt;p&gt;I'm not sure of their current status, but I read some papers based on these models a few years ago:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www2.physics.ox.ac.uk/research/geophysical-fluid-dynamics/research/oxford-planetary-unified-model-system&quot; rel=&quot;noreferrer&quot;&gt;Oxford Planetary Unified Model System&lt;/a&gt; for Venus (OPUS-V), which is based on an old version of the UK Met Office climate model, HadCM3 (&lt;a href=&quot;https://doi.org/10.1016/j.pss.2016.09.001&quot; rel=&quot;noreferrer&quot;&gt;paper&lt;/a&gt; from 2016).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;ROCKE-3D at Nasa GISS, which is based on an old version of the GISS ModelE2‐R climate model (&lt;a href=&quot;https://climate.nasa.gov/news/2475/nasa-climate-modeling-suggests-venus-may-have-been-habitable/&quot; rel=&quot;noreferrer&quot;&gt;blog article&lt;/a&gt; and &lt;a href=&quot;https://doi.org/10.1002/2016GL069790&quot; rel=&quot;noreferrer&quot;&gt;paper&lt;/a&gt; from 2016).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;It looks like the introduction of &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0019103518304846&quot; rel=&quot;noreferrer&quot;&gt;Yamamoto et al&lt;/a&gt; (2019) has a more up-to-date summary of the current set of models, and there's quite a healthy selection from groups around the world.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2019-11-23T19:44:06.217" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18545" PostTypeId="2" ParentId="18541" CreationDate="2019-11-23T20:34:05.727" Score="1" Body="&lt;p&gt;The recent spike in Greenland temperatures is almost at Holocene maximum levels despite the declining trend over the last 7,000 years.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Greenland ice cores provide a high-quality high-resolution estimate of past changes in temperatures, allowing more precise comparisons with observed temperature records than most other climate proxies. While current temperatures are likely still below the highs in the early Holocene around 7,000 years ago, they are clearly higher than any temperatures experienced in Greenland over the past 2,000 years.  &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Greenland is just one location and temperature variations seen in ice core records may not be characteristic of global temperatures. However, global proxy reconstructions have tended to show similar patterns, with current temperatures lower than the early Holocene maximum.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DfQOp.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DfQOp.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.carbonbrief.org/factcheck-what-greenland-ice-cores-say-about-past-and-present-climate-change&quot; rel=&quot;nofollow noreferrer&quot;&gt;What Greenland ice cores say about past and present climate change&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-11-23T20:34:05.727" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18546" PostTypeId="1" CreationDate="2019-11-24T04:29:03.550" Score="2" ViewCount="135" Body="&lt;p&gt;Based on &lt;a href=&quot;https://www.ngdc.noaa.gov/geomag/WMM/DoDWMM.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;this map&lt;/a&gt;,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wojvJ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wojvJ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Below are images showing more specific detail.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/J2Bcl.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/J2Bcl.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8dI3w.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8dI3w.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I assume the field strength is between 0.6 gauss and 0.65 gauss, but I cannot tell between which ios-flux lines (if that is a legitimate term) McMurdo Station is located.  Are there precise measurements of the magnetic field strength at that location, within 0.01 gauss?&lt;/p&gt;&#xA;" OwnerUserId="14986" LastEditorUserId="14986" LastEditDate="2019-11-24T16:23:24.947" LastActivityDate="2019-11-25T20:47:57.967" Title="What is the strength of the Earth's magnetic field at McMurdo Station, Antarctica?" Tags="|geomagnetism|antarctica|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18547" PostTypeId="1" CreationDate="2019-11-24T11:37:56.330" Score="3" ViewCount="40" Body="&lt;p&gt;As the duration of a magnetic reversal can be up to 12,000 years, could there come a time mid-way in the transition when Earth's magnetic field is as negligible as that of Mars or Venus? Magnetic reversals are random, but we haven't had one for nearly a million years, while the average interval is about 300,000 years.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-11-24T13:18:07.943" LastActivityDate="2019-11-24T13:18:07.943" Title="Strength of Magnetic Field at Mid Point of a Reversal" Tags="|geology|reversals|planets|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18548" PostTypeId="1" CreationDate="2019-11-24T15:23:35.047" Score="1" ViewCount="38" Body="&lt;p&gt;I'm trying to generate a landscape and I want to include soil thickness for realism. Data I have is altitude, angle of a given point and moisture of a given point.&lt;/p&gt;&#xA;" OwnerUserId="18392" LastEditorUserId="2470" LastEditDate="2019-11-24T17:14:35.467" LastActivityDate="2019-11-24T17:14:35.467" Title="How is soil thickness related to altitude, angle and moisture?" Tags="|soil|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18549" PostTypeId="1" AcceptedAnswerId="18581" CreationDate="2019-11-24T15:39:17.503" Score="6" ViewCount="388" Body="&lt;p&gt;The NPR.org news article and podcast &lt;a href=&quot;https://www.npr.org/2019/11/24/781598549/greenland-is-not-for-sale-but-it-has-the-rare-earth-minerals-america-wants&quot; rel=&quot;nofollow noreferrer&quot;&gt;Greenland Is Not For Sale. But It Has The Rare Earth Minerals America Wants&lt;/a&gt; is interesting, and it includes a few large GIFs (too large to post here) that appear to show a UV light being waved over some rocks (not really in the dark) and bright red spots lighting up indicating the presence of some mineral containing a rare Earth element.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Compounds containing rare Earth's including oxides have strong transitions in the visible and infrared and some will fluoresce with visible light. When you read what I type over the internet the signal has probably been amplified dozens of times by &lt;a href=&quot;https://en.wikipedia.org/wiki/Optical_amplifier#Basic_principle_of_EDFA&quot; rel=&quot;nofollow noreferrer&quot;&gt;erbium-doped silica fiber optic amplifiers&lt;/a&gt; at the bottom of the ocean (and everywhere else) and those are likely pumped by &lt;a href=&quot;https://en.wikipedia.org/wiki/Nd:YAG_laser&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nd:YAG lasers&lt;/a&gt; (neodymium-doped yttrium aluminum garnet).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But are UV lights really able to so easily find rare Earth-containing rocks on the ground in Iceland, or are these GIFs slightly gratuitous?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Can I just walk around Greenland with a UV light and find rare Earth minerals on the ground?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2019-11-28T22:55:01.707" LastActivityDate="2019-11-28T22:55:01.707" Title="Can I just walk around Greenland with a UV light and find rare Earth minerals on the ground?" Tags="|minerals|light|rare-earth|uv-light|fluorescence|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18552" PostTypeId="1" CreationDate="2019-11-24T22:40:02.350" Score="2" ViewCount="97" Body="&lt;p&gt;I've seen many papers on mineral deposits say something along the line of &quot;a 100,000 tonne deposit of Zn, 1% grade.&quot; Does this mean there is 1% of 100,000 tonnes which is 1000 tonnes pure zinc, or does it mean there is a total zinc deposit of 100,000 which is 1% of the total giving 10,000,000 tonnes including the waste material?&lt;/p&gt;&#xA;" OwnerUserId="18394" LastActivityDate="2019-11-25T04:40:54.557" Title="Ore Reserve Definition" Tags="|mineralogy|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18553" PostTypeId="2" ParentId="18552" CreationDate="2019-11-24T23:43:09.560" Score="-2" Body="&lt;p&gt;It means there is an estimated 100,000 tonnes of recoverable zinc in the lifetime of the mine, and the ore it produces is 1% zinc. As zinc ores usually contain other metals such as lead, it is not necessarily the case that this ore is 99% waste material.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-24T23:43:09.560" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18555" PostTypeId="1" CreationDate="2019-11-25T03:00:09.080" Score="1" ViewCount="83" Body="&lt;p&gt;I am trying to solve the following question but cannot figure out how: &#xA;A layer of limestone has a strike of East to West on a hilltop, and an apparent dip of 40 degrees on the vertical hillside trending N35E. What is the true dip angle and quadrant?&lt;/p&gt;&#xA;" OwnerUserId="18395" LastEditorUserId="18081" LastEditDate="2019-11-25T11:59:40.580" LastActivityDate="2019-11-25T11:59:40.580" Title="How can one find the true dip angle and quadrant when an apparent dip and strike is provided?" Tags="|geology|structural-geology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18557" PostTypeId="1" CreationDate="2019-11-25T03:16:04.280" Score="3" ViewCount="5112" Body="&lt;p&gt;Why do some tectonic plates move faster than others?  Is it due to friction between the plates, the driving forces on the plates, or both?  If it is driving forces, what makes the driving forces on some plates stronger than on others?&lt;/p&gt;&#xA;" OwnerUserId="12694" LastActivityDate="2019-11-25T10:32:50.703" Title="What causes some plates to move faster than others?" Tags="|plate-tectonics|" AnswerCount="2" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18558" PostTypeId="2" ParentId="18552" CreationDate="2019-11-25T04:40:54.557" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://www.911metallurgist.com/ore-reserve-estimation-methods/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ore reserves&lt;/a&gt; represent the economic portion of a mineral deposit. They &lt;a href=&quot;http://are%20reported%20as%20tonnes%20and%20grade%20(quality)%20above%20a%20minimum%20value&quot; rel=&quot;nofollow noreferrer&quot;&gt;are reported as tonnes and grade above a minimum value&lt;/a&gt; (&lt;a href=&quot;https://en.wikipedia.org/wiki/Cutoff_grade&quot; rel=&quot;nofollow noreferrer&quot;&gt;cut-off grade&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Irrespective of whether the ore reserve will be mined by surface or underground methods the deposit is blocked out and the mass of each block and the mass of the valuable commodity (zinc, copper, gold, etc.) is calculated for each block. From this the grade of each block is also determined. The reserve is determined by summing the masses of all the blocks and determining the overall grade of the total.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In your example, a deposit of 100,000 tonnes grading 1% zinc means there is 100,000 tonnes of rock that can be mining and treated by a processing plant (mill). The amount of zinc metal contained within that 100,000 tonnes of rock is 1000 tonnes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Similarly, a gold deposit that contains 2 Mt @ 8 g/t, contains 2 million tonnes of rock grading 8 grams per tonne, or 8 parts per million. The amount of gold contained in that 2 million tonnes is 16,000,000 g (16,000 kg or 16 t).&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-11-25T04:40:54.557" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18562" PostTypeId="2" ParentId="18557" CreationDate="2019-11-25T10:32:08.130" Score="0" Body="&lt;p&gt;As you suggested in your question, one of the things that slows plates down is friction with an adjacent plate. The force that drives them forward is the force of the mantle plume or plumes that split them off in the first place. A very large plume of magma rising from far below sometimes causes a plate to break off from a larger one, and a rift valley develops. Sea floor spreading from within the rift then causes the new plate to drift away, propelled by volcanic forces within the rift and by the mantle plume which still acts on it. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The consistency of the magma underlying the plate will also affect the speed with which it moves. The mantle itself is a plastic solid, but huge magma plumes rising from deep in the mantle lubricate the progress of the plate on top. These magma plumes vary in size and strength, therefore the propulsion they give to the plate they carry varies too.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-25T10:32:08.130" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18563" PostTypeId="2" ParentId="18557" CreationDate="2019-11-25T10:32:50.703" Score="3" Body="&lt;p&gt;The driving forces of plate tectonics has long been debated. Several mechanisms have been proposed, mainly ridge push, mantle drag, and slab pull (see &lt;a href=&quot;https://www.bgs.ac.uk/discoveringGeology/hazards/earthquakes/whatDrivesTectonicPlates.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this page from the British Geological Survey&lt;/a&gt;). However, there is now a good agreement that &lt;strong&gt;slab pull is the main driving force of plate tectonics&lt;/strong&gt;. It means that it is the subducting plate which controls the velocity of the plate's movement. And the rate at which a plate sinks depends mostly on its age/temperature/density: older plates are cooler/denser, thus they sink at a higher velocity than younger plates.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2019-11-25T10:32:50.703" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18564" PostTypeId="1" CreationDate="2019-11-25T14:06:12.603" Score="11" ViewCount="1790" Body="&lt;p&gt;Are Andaman and Nicobar islands in Indian ocean a continuation of Alpide-Himalayan orogeny or are they volcanic in origin?&lt;/p&gt;&#xA;" OwnerUserId="18396" LastEditorUserId="22648" LastEditDate="2021-09-11T09:23:34.973" LastActivityDate="2021-09-11T09:23:34.973" Title="Origin of Andaman and Nicobar islands" Tags="|geology|geomorphology|orogeny|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18566" PostTypeId="2" ParentId="18564" CreationDate="2019-11-25T15:27:14.250" Score="11" Body="&lt;p&gt;The Andaman and Nicobar Islands are neither orogenic or volcanic in origin. &lt;strong&gt;They are in fact an accretionary wedge&lt;/strong&gt;, i.e., an accretion of sediments and oceanic crust &amp;quot;scraped&amp;quot; from the subducting Indian plate. See for instance the description in &lt;a href=&quot;https://doi.org/10.1144/M47.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;the first chapter&lt;/a&gt; of the aptly titled &lt;em&gt;The Andaman–Nicobar Accretionary Ridge&lt;/em&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The islands are an exposed segment of the accretionary wedge (outer arc) of the Sunda subduction system, where the Indian Plate subducts beneath the Sunda Plate. Ongoing uplift of the sediment-dominated accretionary wedge has exposed, over a relatively small area, a diverse range of rock types associated with the subduction complex (dismembered ophiolites, volcanic-arc rocks, trench-slope deposits, submarine fan turbidites, pelagic sediments and the sediments of shelf and reef environments), making it an ideal area for investigating subduction processes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;(Unfortunately, other chapters with more detailed descriptions are not open access.)&lt;/p&gt;&#xA;&lt;p&gt;Note that if some of the sediments are indeed volcanic in origin, it does not mean that volcanism is responsible for building the archipelago, like it was for &lt;a href=&quot;https://en.wikipedia.org/wiki/Chagos-Laccadive_Ridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Chagos-Laccadives ridge&lt;/a&gt; for instance, to stay around India. &lt;strong&gt;It is the accretion of sediments in the subduction trench, and their subsequent uplift above the sea, that created the islands.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2021-09-10T14:41:34.527" LastActivityDate="2021-09-10T14:41:34.527" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18567" PostTypeId="2" ParentId="18546" CreationDate="2019-11-25T20:47:57.967" Score="4" Body="&lt;p&gt;According to the current &lt;a href=&quot;https://www.ngdc.noaa.gov/geomag/calculators/magcalc.shtml#igrfwmm&quot; rel=&quot;noreferrer&quot;&gt;World Magnetic Model 2015 v2&lt;/a&gt; (new one to be released on 10 December 2019!), &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Longitude: 166.6863° E&#xA;Latitude: 77.8419° S&#xA;Elevation: 10 m&#xA;&#xA;Date: 2019-11-25&#xA;Declination (+E | -W):   141.5232°    (-0.1829°/yr)&#xA;Inclination (+D | -U):   -80.3929°    (0.0399°/yr)&#xA;Horizontal Intensity:     10,396.8 nT (34.7 nT/yr)&#xA;North Comp (+N | -S):     -8,139.2 nT (-6.5 nT/yr)&#xA;East Comp (+E | -W):       6,468.8 nT (47.6 nT/yr)&#xA;Vertical Comp (+D | -U): -61,423.3 nT (54.8 nT/yr)&#xA;Total Field:              62,297.0 nT (-48.3 nT/yr)&#xA;&#xA;Uncertainties:  0.57°   0.22°   133 nT  138 nT  89 nT   165 nT  152 nT&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="1339" LastActivityDate="2019-11-25T20:47:57.967" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18569" PostTypeId="1" CreationDate="2019-11-25T22:14:37.873" Score="1" ViewCount="29" Body="&lt;p&gt;I have been looking on the internet and can't find the title subject. Three friends and I spent 2 days snowed in a strangers house in Airdrie AB during May , about 1992. We are talking about close to a meter of snow; Calgary and Edmonton got much less snow. I had been in a gas plant north of Airdrie and was heading back to Calgary . Heavy snow, I stopped the rental car to pick up a stranded couple ( since it was May many locals had removed snow tires).  I went a mile and drifted off the highway in the whiteout. Two guys behind me ( with whom I had worked ) stopped in their pickup with chains , essentially no other cars were moving.  We left the highway at Airdrie to take the stranded couple home . The couple said &quot; you can't go further stay with us&quot;, so we did. Wood stove heat and a lot of venison ( power was off). Roads were not open for two days. I was looking for the official snow fall and possibly other info.  &lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2019-11-25T22:14:37.873" Title="Looking for info on a very heavy snow that fell in Airdrie AB in May of about 1992" Tags="|snow|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18570" PostTypeId="2" ParentId="17912" CreationDate="2019-11-26T04:55:06.640" Score="3" Body="&lt;p&gt;Yes, it is possible. The documentation for Hydrus-3D give you the syntax (&lt;a href=&quot;http://www.pc-progress.com/en/OnlineHelp/HYDRUS3/Hydrus.html?RunningComputationalModulesinaBa.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.pc-progress.com/en/OnlineHelp/HYDRUS3/Hydrus.html?RunningComputationalModulesinaBa.html&lt;/a&gt;)&#xA;In brief here is what you need to do:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;In the installation folder of Hydrus, create a text file, name it run.bat&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;You need to write two lines of code for every  simulation you wish to perform:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;copy path1 level_01.dir      (here path1 can be replace what what ever name you want)&lt;/li&gt;&#xA;&lt;li&gt;h2d_calc                     (this is the executable so depending on the type of model you want to run you may have to adjust the name)&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;In the installation folder of Hydrus create a text file and name it path1 (or whatever name you wrote in step 2), do not forget to remove the .txt extension for the case display here)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;In the path1 file, write the path to your input files&#xA;for example: c:\program files\ussl\hydrus3d\mydirect\run1&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Then double clicking on the bat file will trigger the model to run. By adding successive copy ... and h2d_calc commands you can chain model execution &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition some tricks are available here: &lt;a href=&quot;https://www.pc-progress.com/forum/viewtopic.php?f=4&amp;amp;t=679&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.pc-progress.com/forum/viewtopic.php?f=4&amp;amp;t=679&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18398" LastActivityDate="2019-11-26T04:55:06.640" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18571" PostTypeId="2" ParentId="8346" CreationDate="2019-11-26T05:59:41.010" Score="1" Body="&lt;p&gt;According to Trenberth, Fasullo &amp;amp; Kiehl &lt;a href=&quot;https://journals.ametsoc.org/doi/10.1175/2008BAMS2634.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;update&lt;/a&gt; of the &lt;em&gt;&quot;Earth's global annual mean energy  budget&quot;&lt;/em&gt; seems worlds clouds in average reflects about 23% of incoming sun radiation (about 79 W/m2).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Data from 1997 (that could be outdated) estimates clouds blocks approximately 20-25 W/m2 (6-7% of surface radiation). If so, aerosols has a small role in IR block, and the main part is due to CO2, water vapor, methane and other greenhouse gases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the way clouds overlap on the downward flux of heat with other greenhouse gases introduces uncertainties. Another  source of error is the amount of water vapor between the surface and the cloud base. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kate Marvel wrote: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;“To accurately model clouds, we’d have to track the behavior of every&#xA;  water droplet and dust grain in the entire atmosphere, and there’s no&#xA;  computer powerful enough to do that,”&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In general, seems clouds is the main source of uncertainty in models.&lt;/p&gt;&#xA;" OwnerUserId="18399" LastActivityDate="2019-11-26T05:59:41.010" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18572" PostTypeId="2" ParentId="18549" CreationDate="2019-11-26T06:49:32.903" Score="2" Body="&lt;p&gt;I think the answer to your question have to be no.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lots of minerals are fluorescent in UV light,You can take a look here &lt;a href=&quot;https://geology.com/articles/fluorescent-minerals/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://geology.com/articles/fluorescent-minerals/&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So as you can see in the linked summary of fluorescent minerals it can be hard to tell what you have found unless you know what to look for.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A better way to find Rare Earth Elements might be to use a Geigercounter,Many of the Rare Earth Elements can be found toghether with radioactive minerals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is an example from Norway &lt;a href=&quot;https://reeminerals.no/fens-field&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://reeminerals.no/fens-field&lt;/a&gt; this is an area not far from where i live.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see in the linked article this area can be seen using detectors from an airplane,Maybe not to tell the composition but it can give a hint about where to look.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastActivityDate="2019-11-26T06:49:32.903" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18573" PostTypeId="2" ParentId="18310" CreationDate="2019-11-26T12:23:04.377" Score="1" Body="&lt;p&gt;This answer might be a bit late but here are some common metadata variables that get recorded:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a CTD:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Operator &lt;/li&gt;&#xA;&lt;li&gt;Date and time&lt;/li&gt;&#xA;&lt;li&gt;Start and end co-ordinates of station &lt;/li&gt;&#xA;&lt;li&gt;Station Number &lt;/li&gt;&#xA;&lt;li&gt;Sample depths (assuming you'll also be collecting water samples)&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Here you can also record what the water samples are used for i.e. salinities, chemistry etc&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;Sea state&lt;/li&gt;&#xA;&lt;li&gt;Vessel&lt;/li&gt;&#xA;&lt;li&gt;File name&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;For the ADCP:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Start and end co-ordinates&lt;/li&gt;&#xA;&lt;li&gt;Date and time&lt;/li&gt;&#xA;&lt;li&gt;ADCP type&lt;/li&gt;&#xA;&lt;li&gt;Set-up (sampling frequency, bin size)&lt;/li&gt;&#xA;&lt;li&gt;Vessel&lt;/li&gt;&#xA;&lt;li&gt;Operator&lt;/li&gt;&#xA;&lt;li&gt;File name&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="12663" LastActivityDate="2019-11-26T12:23:04.377" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18575" PostTypeId="1" CreationDate="2019-11-26T13:52:56.167" Score="3" ViewCount="323" Body="&lt;p&gt;Iceland sits atop a divergent ocean-ocean boundary. But there are not many islands which are formed along a divergent boundary. Why is it so? Why do not mid ocean ridges often rise above the sea surface to form islands? Why are islands more common along convergent plate boundaries where they often form archipelagos? &lt;/p&gt;&#xA;" OwnerUserId="18396" LastEditorUserId="5594" LastEditDate="2019-12-13T15:42:43.600" LastActivityDate="2019-12-13T15:42:43.600" Title="Formation of Iceland" Tags="|geology|geomorphology|tectonics|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18579" PostTypeId="2" ParentId="18575" CreationDate="2019-11-26T19:21:38.983" Score="0" Body="&lt;p&gt;The reason islands don't form along divergent plate boundaries is that these boundaries are at the bottom of the sea, and usually quite deep. Although mid ocean ridges are volcanic, the magma doesn't get a chance to pile up and reach the surface because the plates are not static. They are slowly spreading apart, and the magma is needed to form fresh oceanic crust between them. The logical place for sea floor spreading is at the bottom of the sea. I only know of one other place where this happens on land, and that is in the Afar region of Ethiopia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Islands are common on convergent plate boundaries because volcanism is common on convergent plate boundaries. This is where oceanic crust is subducted. Volcanoes and other phenomena connected with subduction tend to form islands. The Pacific 'ring of fire' is an example of this.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-11-26T19:21:38.983" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18581" PostTypeId="2" ParentId="18549" CreationDate="2019-11-26T22:15:36.787" Score="2" Body="&lt;h1&gt;Yes, definitely.&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;In general, REE minerals tend to be fluorescent. In our lab we deal a lot with REE and we have a UV lamp just for fun, to see the colours. Other minerals that are commonly associated with REE deposits are also fluorescent, with the best example being calcite, fluorite, and apatite.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fluorescent properties of REE-bearing solid state compounds (i.e., REE minerals) are exactly the reason why they're so commonly used in phosphors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Greenland, in particular, is the best way in the world for that. Because it is glaciated, rock surfaces are freshly exposed with very little alteration or development of soil that will hide the REE minerals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whether this is an effective exploration method is debatable, but it is definitely part of the toolbox of any exploration geologist working on REE deposits. And it looks really cool.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2019-11-26T22:15:36.787" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18582" PostTypeId="1" AcceptedAnswerId="19293" CreationDate="2019-11-27T00:36:25.667" Score="6" ViewCount="307" Body="&lt;p&gt;If I understand &lt;a href=&quot;https://earthscience.stackexchange.com/a/18581/6031&quot;&gt;this answer&lt;/a&gt; and &lt;a href=&quot;https://earthscience.stackexchange.com/questions/18549/can-i-just-walk-around-greenland-with-a-uv-light-and-find-rare-earth-minerals-on/18581?noredirect=1#comment40159_18581&quot;&gt;this comment&lt;/a&gt; correctly, minerals like calcite, fluorite, and apatite are &quot;commonly associated with (Rare Earth Element) REE deposits&quot;, and like some REEs also fluoresce when exposed to UV light. But the intrinsic fluorescent properties of those minerals are not caused by REEs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this just a pleasant coincidence; the presence of one fluorescent mineral is often associated with the presence of another fluorescent mineral even though their fluorescence mechanisms are different?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or do minerals like calcite, fluorite, and apatite tend to fluoresce &lt;em&gt;because&lt;/em&gt; they contain REEs, thus observation of their fluorescence is a direct indicator of the presence of REEs? Or do REEs only &lt;em&gt;modify the color&lt;/em&gt; of their fluorescence, but not necessarily cause it?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2020-01-31T10:15:48.547" LastActivityDate="2024-01-26T18:58:40.183" Title="Is the association of fluorescent minerals calcite, fluorite, and apatite with fluorescent rare-Earth minerals a coincidence?" Tags="|mineralogy|rare-earth|fluorescence|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18583" PostTypeId="1" CreationDate="2019-11-27T02:13:01.707" Score="3" ViewCount="177" Body="&lt;p&gt;I experience this weird feeling for the last three months. Every night, at exactly 3AM I can feel small earthquake and I could not find anything on the internet related to it. Does anyone have any information about this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit.&#xA;I live in Europe, Bosnia and Herzegovina, Mostar.&lt;/p&gt;&#xA;" OwnerUserId="18401" LastEditorUserId="2470" LastEditDate="2019-11-27T02:25:37.707" LastActivityDate="2023-04-07T01:58:55.397" Title="Small earthquake happening every night at the exact same time" Tags="|seismology|" AnswerCount="0" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="18584" PostTypeId="1" CreationDate="2019-11-27T07:39:44.817" Score="1" ViewCount="60" Body="&lt;p&gt;I'm Erfan from Yemen, I found this stone in my village's mountain, it looks not normal stone, it's shinning like a crystal and headlight can penetrate it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are hundreds of it in the mountain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can you tell me please what it's kind, and does it precious stone?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My Regards&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/bCL4h.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="18403" LastActivityDate="2019-11-27T07:39:44.817" Title="Inquiry, Is this Crystal?" Tags="|geology|" AnswerCount="0" CommentCount="2" ClosedDate="2019-11-28T00:27:52.013" ContentLicense="CC BY-SA 4.0" />
  <row Id="18585" PostTypeId="2" ParentId="17998" CreationDate="2019-11-27T08:03:42.073" Score="0" Body="&lt;p&gt;If you are interested in the element ratios, you are looking at their relative abundance, not the absolute abundance. Therefore, as long as all the data you are comparing come from XRF, you do not need to normalise them for the ratio calculations in the plots.&lt;/p&gt;&#xA;" OwnerUserId="4783" LastActivityDate="2019-11-27T08:03:42.073" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18586" PostTypeId="1" CreationDate="2019-11-27T08:16:45.440" Score="1" ViewCount="74" Body="&lt;p&gt;I am using ERA5 soil moisture for drought analysis. I do not understand what negative values for soil moisture means, could someone please offer an explanation?  &lt;/p&gt;&#xA;" OwnerUserId="18380" LastEditorUserId="2470" LastEditDate="2019-11-27T17:00:05.337" LastActivityDate="2019-11-27T17:00:05.337" Title="What the negative values in ERA5 soil moisture represent?" Tags="|climate|" AnswerCount="0" CommentCount="4" ClosedDate="2019-11-27T12:56:00.490" ContentLicense="CC BY-SA 4.0" />
  <row Id="18587" PostTypeId="1" CreationDate="2019-11-27T11:19:36.983" Score="2" ViewCount="12517" Body="&lt;p&gt;A quite simple question that I hope someone can help me with. I have a massive database of hourly minimum and maximum temperatures, from many automatic weather stations. I need to estimate the average monthly minimum, maximum and mean temperatures for each stations, like that provided by climatologies such as bioclim, worldclim, CHELSA, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given the following one-day example data:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;         Date Time tMin tMax&#xA;1  2009-05-01    0 24.2 24.4&#xA;2  2009-05-01  100 24.1 24.3&#xA;3  2009-05-01  200 24.0 24.2&#xA;4  2009-05-01  300 23.8 24.1&#xA;5  2009-05-01  400 23.7 23.9&#xA;6  2009-05-01  500 23.6 23.8&#xA;7  2009-05-01  600 23.5 23.6&#xA;8  2009-05-01  700 23.5 23.7&#xA;9  2009-05-01  800 23.3 23.7&#xA;10 2009-05-01  900 23.4 23.5&#xA;11 2009-05-01 1000 23.4 24.2&#xA;12 2009-05-01 1100 24.2 26.2&#xA;13 2009-05-01 1200 26.2 28.4&#xA;14 2009-05-01 1300 27.5 29.8&#xA;15 2009-05-01 1400 28.3 30.1&#xA;16 2009-05-01 1500 28.4 30.9&#xA;17 2009-05-01 1600 30.5 31.7&#xA;18 2009-05-01 1700 30.7 31.9&#xA;19 2009-05-01 1800 29.5 31.2&#xA;20 2009-05-01 1900 27.9 30.6&#xA;21 2009-05-01 2000 27.6 28.6&#xA;22 2009-05-01 2100 26.3 27.6&#xA;23 2009-05-01 2200 25.3 26.2&#xA;24 2009-05-01 2300 24.6 25.7&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;How do I calculate the required parameters? I'm confused between two options:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Simply by calculating the average of each column each day, and then averaging these averages to calculate the mean temperature: (tMin average: 25.7; tMax average:  26.8; and tMean: 26.2). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Picking the lowest daily minimum temperature (23.3), and the highest daily maximum temperature (31.9), and then averaging both (27.6).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then, once I've got the dailies information estimated, I think I must to calculate the overall average for each of the three parameters each month.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any feedback will be more than appreciated!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Best!&lt;/p&gt;&#xA;" OwnerUserId="14509" LastEditorUserId="14509" LastEditDate="2019-11-27T18:48:17.057" LastActivityDate="2019-12-02T21:48:14.787" Title="How to calculate maximum and minimum mean monthly temperatures?" Tags="|meteorology|temperature|climatology|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18588" PostTypeId="1" CreationDate="2019-11-27T14:32:00.863" Score="2" ViewCount="159" Body="&lt;p&gt;Mount Kinabalu in North Borneo is a 10 million year old pluton. A pluton is a magma plume from the mantle which was not able to reach the surface and erupt as a volcano, but solidified underground and has since been exposed by erosion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is reported that Kinabalu is rising at a rate of 5mm per year, pushed up by forces from below. In 2015 there was a powerful earthquake which killed 18 people. With volcanoes, rising terrain and earthquakes are often a portent of more dramatic things to come, though not necessarily imminently. Could this also be true of plutons?&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-13T19:13:24.910" Title="Could Rumblings From Plutons be as Ominous as Rumblings From Volcanoes?" Tags="|volcanology|earthquakes|geomorphology|magma-plumes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18590" PostTypeId="2" ParentId="18587" CreationDate="2019-11-27T18:00:24.063" Score="0" Body="&lt;p&gt;This is not an answer&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;code&gt;average monthly minimum, maximum and mean temperatures&lt;/code&gt;... I'm missing something. Why not take the highest temperature in May 1960, May 1961, May 1962, and so on, and average. That would give you the average highest temperate for May. You can do something similar for average lowest temperate. For mean temperature, you'll have to average all the hourly highs and lows. As @Jean-MariePrival points out, this isn't necessarily accurate, but may be the best you can do. Question: where did you get hourly minimum an maximum data? I know where to get hourly data, but not mins and maxs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you could, please add your source to: &lt;a href=&quot;http://opendata.stackexchange.com/questions/10154/sources-of-weather-data/&quot;&gt;http://opendata.stackexchange.com/questions/10154/sources-of-weather-data/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user967" LastActivityDate="2019-11-27T18:00:24.063" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18591" PostTypeId="1" CreationDate="2019-11-28T06:44:53.513" Score="8" ViewCount="172" Body="&lt;p&gt;I am interested in the linkage between the cyclical timing of human activity, and whether that has a direct affect on weather.  Most obvious to me is the weekly cycle, which is observed by most of the world.&lt;/p&gt;&#xA;&lt;p&gt;For example, humans generally produce &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S1352231018307854&quot; rel=&quot;nofollow noreferrer&quot;&gt;less air emissions on the weekends&lt;/a&gt; because they do not have to commute to work, and some businesses are less active.  This means there are less cars on the road (or for less time) and therefore &lt;a href=&quot;https://www.researchgate.net/publication/11080531_Modeling_the_Effect_of_Weekday-Weekend_Differences_in_Motor_Vehicle_Emissions_on_Photochemical_Air_Pollution_in_Central_California&quot; rel=&quot;nofollow noreferrer&quot;&gt;less vehicular emissions&lt;/a&gt;.  In some cities, this can lead to an effect during the summer where ozone concentrations are higher on weekdays and reduced on the weekends.  There are also instances where human activity can lead to higher particulate emissions on weekdays, which could cause weekly patterns in fog or albedo. In general, if the radiation budget is perturbed, it could theoretically affect weather.&lt;/p&gt;&#xA;&lt;p&gt;Perhaps there are other examples too.  So, is there any link between the weekly human cycle and weather?&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2022-02-06T18:25:16.413" LastActivityDate="2022-02-16T00:15:18.873" Title="Is there any link between the weekly human cycle and weather?" Tags="|meteorology|human-influence|air-quality|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="18592" PostTypeId="2" ParentId="18524" CreationDate="2019-11-28T16:34:00.500" Score="1" Body="&lt;p&gt;Alec Bennett calculates resistance to heat flux values in an urban canyon as part of his MSc in meteorology dissertation: &lt;a href=&quot;http://www.met.reading.ac.uk/mscdissertations/Heat%20Fluxes%20from%20Street%20Canyons.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Heat Fluxes from Street Canyons&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The calculated values range from 76.6 to 84.2 and are based on measurements taken on May 18th and 19th 2004 from 08:00 to 17:00 (both days).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See the two tables in the Appendix on page 68 for the full range of values.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have not read the entire thesis.  It's unclear to me what confidence I should place in these values.&lt;/p&gt;&#xA;" OwnerUserId="18379" LastEditorUserId="18379" LastEditDate="2019-11-28T21:32:22.893" LastActivityDate="2019-11-28T21:32:22.893" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18594" PostTypeId="1" CreationDate="2019-11-29T16:17:29.843" Score="3" ViewCount="247" Body="&lt;p&gt;Below is the Dallas precipitation forecast I just got (requested from Google&#xA;at 10am, Nov 29, 2019).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From this, what is the probability that a 10cm (diameter) cup placed in a&#xA;Dallas park from 4:00pm will have some visible water in it at 4:10pm?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What about at 4:20pm?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have never understood what the 61% in the chart really is forecasting&#xA;and really want to know the probability of my getting hit by a liter of&#xA;rain in a random 20 minute run...just asking two simpler questions here to&#xA;work my way up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/A7CtG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/A7CtG.png&quot; alt=&quot;Dallas Precipitation Forecast&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18294" LastActivityDate="2020-01-02T11:07:02.857" Title="How to interpret precipitation probability?" Tags="|weather-forecasting|precipitation|united-states|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18595" PostTypeId="2" ParentId="18594" CreationDate="2019-11-29T17:05:04.470" Score="1" Body="&lt;p&gt;Given only this information and nothing else, there isn't really a definitively correct answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In reality, it depends on the nature of the precipitation. 61% could mean that there is a 61 percent chance of a thunderstorm between 4 and 5 PM, but since thunderstorms are short-lived, it might only be raining for 10 out of 60 minutes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;61% could also mean that an area of precipitation has a 61% chance of passing over Dallas. If that's the case, then it might be a 61% chance of rain for the entirety of the hour and a 39% chance of no rain at all.&lt;/p&gt;&#xA;" OwnerUserId="18303" LastActivityDate="2019-11-29T17:05:04.470" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18596" PostTypeId="1" AcceptedAnswerId="18603" CreationDate="2019-11-30T20:46:20.867" Score="9" ViewCount="7968" Body="&lt;p&gt;I had participated in a quiz recently and one of the questions was 'which is the largest island in the world?'. I wrote Australia as the answer remembering that it was the 5th largest country in the world and none of the top 4 were islands.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However (and rather dreadfully) the answer given was Greenland.I took this up with the committee providing the solutions, but they simply said that Australia isn't an island and is a continental mass?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I googled it and found the same argument online which seemed to confirm that Greenland was the largest island.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But Australia is a country and the collection of islands which is a continent (more accurately described as Oceania ) is sometimes called Australia. Neither of these names would still change the fact that Australia (the country) being an island is the largest island in the world! Can someone please clarify this for me?&lt;/p&gt;&#xA;" OwnerUserId="18410" LastEditorDisplayName="user20559" LastEditDate="2021-11-11T07:33:51.340" LastActivityDate="2023-06-17T04:24:37.810" Title="Is Australia the largest island?" Tags="|geography|continent|islands|" AnswerCount="4" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="18598" PostTypeId="2" ParentId="18596" CreationDate="2019-11-30T22:33:52.073" Score="3" Body="&lt;p&gt;Australia can be seen as a very &quot;continenty&quot; continent. It contains very old stable continental lithosphere in cratons, like for instance the Pilbara or the Yilgarn craton.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I fear, the quiz makers were correct with classifying Australia as a continent.&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastActivityDate="2019-11-30T22:33:52.073" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18599" PostTypeId="2" ParentId="17311" CreationDate="2019-11-30T23:24:24.643" Score="2" Body="&lt;p&gt;Simulating the conditions in earth's core is difficult. Maybe one day it can be done. Until then, we must live with indirect methods.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sulphide fractionation towards the core is a valid hypothesis.&#xA;&lt;a href=&quot;https://www.geochemicalperspectivesletters.org/article1506&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.geochemicalperspectivesletters.org/article1506&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &quot;lead paradoxa&quot; express another inequality in earth's fractionation, if compared to for example meterorites.&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastActivityDate="2019-11-30T23:24:24.643" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18600" PostTypeId="2" ParentId="18575" CreationDate="2019-11-30T23:41:49.093" Score="1" Body="&lt;p&gt;Iceland isn't only situated on a divergent boundary (which in itself can rise up to shallow depths because of higher static and dynamic lift btw.) but also on a (postulated) pretty deep rooted mantle plume that may produce enough magma to rise to subaerial heights.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: The magma that erupts at an ocean ridge is &quot;welded&quot; to the sides (&quot;sheeted dykes&quot;). According to the actual understanding, it is the pull of the subducting plate(*) at a convergent boundary that drives ocean spreading, thus &quot;stretching&quot; things rather than causing them to pile up. The rates at which magma is produced at a ridge is too low to fully compensate for that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Islands, if not forming an arc and situated intra-plate, frequently have a plume under them or are fed from fingers of a plume from the side. In the case of Iceland it is (probably) the plume (in co-operation with &quot;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0012821X17301784&quot; rel=&quot;nofollow noreferrer&quot;&gt;viscous fingering&lt;/a&gt;&quot;) that produces enough material for a subaerial edifice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(*) ... before somebody objects: not necessarly the plate connected to that ridge, but another one elsewhere, and the earth as a whole can't shrink or grow and also isn't exactly hollow ;-)&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user18411" LastEditDate="2019-12-01T10:57:47.947" LastActivityDate="2019-12-01T10:57:47.947" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18601" PostTypeId="2" ParentId="418" CreationDate="2019-12-01T00:22:45.267" Score="1" Body="&lt;p&gt;New(ish) work on the matter:&#xA;&lt;a href=&quot;https://www.nature.com/articles/s41598-018-33823-y&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/s41598-018-33823-y&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;tl,dr: &quot;Modern style&quot; plate tectonics may be (at least) as old as 2.2Gy, probably having started 2.5Gy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Expanding as requested:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The paper is not paywalled. It is about a metamorphic (by temperature and pressure altered) rock that fits in a regime that is typically connected to high pressure/low temperature metamorphosis like it would be met in a subduction zone. The regime is inferred from the mineral composition (based on the assumption that certain minerals or their absence are a marker for certain conditions) and dated by U/Pb decay. The age of the metamorphisis event was thus dated to 2.1 to 2.2 Gy. Assuming that the corresponding Wilson cycle must have begun earlier, the authors suggest a date of 2.5Gy for the onset of modern style tectonics (but don't exclude earlier events).&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user18411" LastEditDate="2019-12-01T01:50:20.200" LastActivityDate="2019-12-01T01:50:20.200" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18602" PostTypeId="2" ParentId="18537" CreationDate="2019-12-01T00:57:11.137" Score="2" Body="&lt;p&gt;Adding to the answer, the cold and dense slab that pulls the oceanic crust behind it down into mantle may rip off and sink down, causing a &quot;sudden&quot; change in buoyancy of the anyway less dense overlying continental crust. That way we have mountain ranges that quite well mark the main subduction zones on earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: ok, expanding a bit on the buoyancy thing:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In principle, continental crust has a density of ~2.7g/cm³, oceanic crust ~3. A search for &quot;continental rifting&quot; and start of a &quot;Wilson cycle&quot; will clarify how an ocean can start off. From an ocean ridge to a continental margin, oceanic crust cools, densifies and sinks into the partly molten and ductile upper mantle, the &quot;asthenosphere&quot;. Thus ocean floor depth is a function of age, reaching up to 5.5km, in special cases more. The oceanic crust stays welded to the adjacent continent until it has cooled down and densified enough that it literally rips off(*) and starts to sink into the asthenosphere. While it does, it drags the rest of the oceanic crust behind it, and the eventually thick layers of sediments that had been deposited from the continent get sheared off to form an &quot;accretionary wedge&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sediment layer can be considerably thick, many km for instance on the jurassic (pretty old and deep) ocean floor under Lanzarote and Fuerteventura off the African coast, and elsewhere of course.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sinking oceanic crust stays cooler and denser while sinking down through the mantle. Such zones have been identified by seismics under several mountain ranges. Eventually, the weight of the &quot;dangling&quot; cold and dense ex-ocean floor gets too high so that it rips off. The overlying continental crust, suddenly released from an enormous weight, starts to rise quickly, sediments become exposed, erosion kicks in, and voila, valleys deep &amp;amp; mountains high form, with pretty picturesque sediment packages and their contents, today whale bones, in future plastic :-/&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Examples for slabs: several stages of detached slabs under the Alps, fragmented slabs under the Himalaya, under the Cordilleres, Andes, ...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(*) This explains also why oceanic crust has a maximum age, best consumed before :-)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Oh, and in some cases, fragments of the ocean floor can be deposited between sediments and stay afloat. When it is exposed, this is called an &quot;ophiolite&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope that helps :-)&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user18411" LastEditDate="2019-12-04T20:38:36.383" LastActivityDate="2019-12-04T20:38:36.383" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18603" PostTypeId="2" ParentId="18596" CreationDate="2019-12-01T01:46:53.597" Score="8" Body="&lt;p&gt;Australia does get widely referred to as an island as well as as a continent - an island-continent sometimes. My understanding is that &quot;continent&quot; in terms of geology refers to the largest land mass of a continental plate and is more a matter of convention - a general agreement - than precise definition. Such definitions have been subject to revision. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This definition would have come after continental plates and plate tectonics were confirmed and widely accepted; proposed first by Alfred Wegener in 1912, acceptance did not come until the 1950's and 60's. Naming Australia an island predated this definition and still persists in popular usage but using the current definition it is a continent. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Greenland, being a part of the North American Plate but not it's largest landmass, gets defined as an island and is now considered the world's largest island.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="18145" LastEditDate="2019-12-01T01:52:22.387" LastActivityDate="2019-12-01T01:52:22.387" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18605" PostTypeId="2" ParentId="18588" CreationDate="2019-12-01T11:08:06.693" Score="1" Body="&lt;p&gt;I searched the mentioned earthquake, and if i understood it right it is attributed to a fault line formed by two laterally moving crustal units (a &quot;normal fault&quot;). Mount Kinabara itself is not to blame, though the earthquake triggered landslides as secondary effects at its steep flanks. I also found papers on the geological history of the area that offer explanations of the causes of the earthquake. As to portents and the future, if only i knew ... :-)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is this publication (&lt;a href=&quot;https://link.springer.com/article/10.1186/s40562-017-0072-9&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wang et. al. 2015, open access&lt;/a&gt;) about the earthquake attributing it to a normal fault directly beneath Mt Kinabalu. The epicentre's position is marked on a profile in the publication.&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user18411" LastEditDate="2019-12-13T19:13:24.910" LastActivityDate="2019-12-13T19:13:24.910" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18606" PostTypeId="2" ParentId="2900" CreationDate="2019-12-01T15:47:05.460" Score="1" Body="&lt;p&gt;The Real Earth server from SSEC seems to be a good choice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://realearth.ssec.wisc.edu/doc/dataaccess.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://realearth.ssec.wisc.edu/doc/dataaccess.php&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="669" LastActivityDate="2019-12-01T15:47:05.460" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18607" PostTypeId="1" CreationDate="2019-12-01T15:56:53.500" Score="4" ViewCount="110" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YbgwF.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YbgwF.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;Here is a GOES visible image from today, 2019-12-01 about local noon, around Nova Scotia. Note the parallel trains or streaks of clouds, running approximately northwest to southeast.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A few hours ago, the wind was from the NW at 30-40kph (at Halifax); for the past 3 hours it's been from the NNW at about 25kph.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What's the physics behind the streaking? Is it simply cumulus clouds from convection being blown downwind?&lt;/p&gt;&#xA;" OwnerUserId="669" LastEditorUserId="669" LastEditDate="2019-12-01T16:58:18.807" LastActivityDate="2020-04-29T19:49:39.120" Title="GOES image: parallel trains of clouds. What to make of them?" Tags="|clouds|weather-satellites|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18608" PostTypeId="2" ParentId="18607" CreationDate="2019-12-01T16:08:11.757" Score="0" Body="&lt;p&gt;My wild guess would be windshear at a low level inversion. Cold calm air below, warm windy air above, with clouds forming at the inversion. Could be checked with a look at an atmospheric &lt;a href=&quot;http://weather.uwyo.edu/upperair/sounding.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;sounding&lt;/a&gt; with wind, temperature and due point curve from the area and the time ...&#xA;&lt;a href=&quot;https://www.aviationweather.ws/046_Wind_Shear.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cartoon&lt;/a&gt; for visuals&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastActivityDate="2019-12-01T16:08:11.757" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18611" PostTypeId="1" CreationDate="2019-12-02T05:46:29.357" Score="5" ViewCount="86" Body="&lt;p&gt;The Sacramento Bee news article &lt;a href=&quot;https://www.sacbee.com/news/california/article237937419.html&quot; rel=&quot;noreferrer&quot;&gt;Toxic fog may be poisoning some of California’s mountain lions, study says&lt;/a&gt; says&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Algae in the ocean convert mercury to methylmercury, its most toxic form, &lt;strong&gt;which can be reabsorbed into the atmosphere&lt;/strong&gt; and come ashore as marine fog, the release says.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Methylmercury [CH&lt;sub&gt;3&lt;/sub&gt;Hg]&lt;sup&gt;+&lt;/sup&gt; is an ion with an atomic mass well over 200. I don't think that it would readily evaporate, so how can it be reabsorbed into the atmosphere?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2020-06-25T23:41:51.590" Title="How can methylmercury in the ocean be reabsorbed into the atmosphere?" Tags="|atmosphere|oceanography|air-pollution|pollution|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18612" PostTypeId="2" ParentId="18587" CreationDate="2019-12-02T11:13:47.687" Score="1" Body="&lt;p&gt;From my experience, first of all, you should calculate the hourly average, in your case should be the average of the 2 minimum and 2 maximum temperatures. (In your sample data you need the 0:00 hours of 2009-05-02, as it is covering 23 hours)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once you have the average by hour in a day, you can go for the daily average, then monthly average and so on...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the minimum and maximum, there is no average, it should be just one value. If you want to calculate a monthly minimum average, then it should be calculated with the same process, so there is just one minimum by hour (the minimum in the range, f.e. 0:00-1:00), then one average of all the hourly minimums to get the daily minimum, and the same system for the monthly one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you try, you will see that you don´t have exactly the same result than making a daily average. For your sample, the daily average by hour is 26.31 degrees and by the daily average of all data is 26.25 degrees.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope it helps!&lt;/p&gt;&#xA;" OwnerUserId="18035" LastActivityDate="2019-12-02T11:13:47.687" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18613" PostTypeId="2" ParentId="17311" CreationDate="2019-12-02T13:35:37.280" Score="6" Body="&lt;p&gt;We know the density of the core from seismology.&lt;br&gt;&#xA;We also know the density of pure iron at given pressure (P) and temperature (T).&lt;br&gt;&#xA;From these two, people have long noticed that there is a discrepancy: the actual core is lighter than a theoretical core made of pure iron. This is known as the &lt;a href=&quot;https://doi.org/10.1016/S0031-9201(02)00017-1&quot; rel=&quot;noreferrer&quot;&gt;Core Density Deficit&lt;/a&gt; (CDD). To explain this CDD, we need to add light elements in the core composition. There are many candidates, such as sulphur, carbon, silicon, oxygen, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is actually needed by geochemists, who try to relate the Earth's composition to that of chondrite. They find that the Bulk Silicate Earth (BSE = crust + mantle) is depleted in some elements compared to the chondritic reference, and have to invoke a hidden reservoir to explain this. For some elements, &lt;a href=&quot;https://www.nature.com/articles/35051064&quot; rel=&quot;noreferrer&quot;&gt;this reservoir could be the core&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To further constrain this, petrologists run some high-P/high-T experiments to see the behaviour of elements during the Earth differentiation. Some elements are said to be lithophile, meaning they will stay in the BSE, while other elements are considered siderophile, hence should have joined the metal phase during segregation of the core. The problem is that some experiments disagree with others, as the behaviour of a given element can change depending on the conditions. For instance, niobium and tantalum are considered lithophile, but can be &lt;a href=&quot;https://www.nature.com/articles/ngeo2195&quot; rel=&quot;noreferrer&quot;&gt;siderophile in reduced conditions&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm afraid the bottom-line of all this is: there is no simple answer to this question...&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2019-12-02T13:35:37.280" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18614" PostTypeId="2" ParentId="18136" CreationDate="2019-12-02T19:21:14.553" Score="2" Body="&lt;p&gt;It is not only Milankovic cycles, these are often overrated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Starting in the Cretaceous, thoughout the Paleo- and Neogene the world went from a greenhouse to an ice age that culminated in the Pleistocene. Much is attributed to the arrangement of continents (large landmass to the southpole), change in ocean currents,&#xA;and slow accumulation of ice shields and rising albedo. This is a positive feedback actually, whose reversal (observations from Greenland and recently even Antactica) have led to corrections in climate models, making the projected ocean level rise and arrival of tipping points that will develop their own dynamic even worse. This is very concerning !&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But back to the question with two examples, that can be researched:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, when Antarctica and Australia separated ~35My ago, a circumpolar current developed that cut off the continent from global circulation so that the iceshields could be maintained and more accumulated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Second, when the isthmus between the Americas closed ~3My ago, ocean currents changed, the gulf stream developed that transports heat and moisture to Europe and north eastern America. The gulf stream can switch states (See: north atlantic deep water (NADW) forming), changing temperature and precipitation patterns, contributing to ice shield build up and retreat in the north.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are just a few highlights to answer how the earth entered the current ice age, there would be much more to write. Other &quot;ice houses&quot; in earth's history (e.g. Permian glaciation) may have had other causes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope that helped a bit :-)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: but a related, mesmerizing question is: if a hypothetical global ice age really existed, how did the earth find out of that ? The high albedo from a global snow/ice cover would prevent that. Somebody painted it black :-) ?&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user18411" LastEditDate="2019-12-02T19:37:53.397" LastActivityDate="2019-12-02T19:37:53.397" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18615" PostTypeId="2" ParentId="18587" CreationDate="2019-12-02T21:48:14.787" Score="1" Body="&lt;p&gt;You can easily calculate the monthly minimum and monthly maximum temperatures since you have these data directly (even though a temporal resolution of one hour is quite coarse in my view, but it, of course, depends on the application).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can only try to estimate the average monthly temperature, which is somewhere between the average minimum and average maximum temperature. You should not pick the lowest and highest values and divide by two as you suggest. Then it would be better to take the average of all values (min and max). This is still not very good, but as the error decreases as &lt;span class=&quot;math-container&quot;&gt;$N^{-1/2}$&lt;/span&gt; then it will be a better estimate at least.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just to give you some ideas: I am wondering if it would be better to use a maximum likelihood approach, e.g. solve for the mode instead of the mean. Note that if your data is truly Gaussian the mode equals the mean.&lt;/p&gt;&#xA;" OwnerUserId="17522" LastActivityDate="2019-12-02T21:48:14.787" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18616" PostTypeId="1" AcceptedAnswerId="18659" CreationDate="2019-12-03T02:14:30.933" Score="8" ViewCount="334" Body="&lt;p&gt;I want to know the current lapse rate for a given point in the US. In other words, I want &quot;live&quot; temperature data at various altitudes. Live is flexible -- I'm generally OK with a forecast which is valid for the current point in time. Where can I get this data, preferably in a format that's easy to ingest into Python?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;More details:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm currently using a lapse rate constant to try to estimate the temperature at various altitudes, but would like to use something more sophisticated. I'm a pilot, so I initially thought about using the Temps &amp;amp; Winds Aloft product, and then interpolating between the sporadic sites, but then I found the &lt;a href=&quot;https://rucsoundings.noaa.gov/&quot; rel=&quot;noreferrer&quot;&gt;models on NOAA's site&lt;/a&gt;. But:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;I'm not clear on which one is best for my use case. Op40 seems to be a good default. But the &lt;a href=&quot;https://rapidrefresh.noaa.gov/hrrr/&quot; rel=&quot;noreferrer&quot;&gt;HRRR model&lt;/a&gt; seems even better, specifically due to the higher resolution.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;I'm not sure where raw data in a format that I can use. If, e.g., I create an interactive skew plot for Op40 on the NOAA site, I can then click the &lt;em&gt;Get Text&lt;/em&gt; button and get the type of info I'm interested in:&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rmf3T.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rmf3T.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But if I choose the &lt;em&gt;ASCII Text&lt;/em&gt; on the first page I get a &lt;a href=&quot;https://rucsoundings.noaa.gov/get_soundings.cgi?data_source=Op40&amp;amp;latest=latest&amp;amp;start_year=2019&amp;amp;start_month_name=Nov&amp;amp;start_mday=28&amp;amp;start_hour=5&amp;amp;start_min=0&amp;amp;n_hrs=1.0&amp;amp;airport=38.702743%2C-123.433474&amp;amp;text=Ascii%20text%20%28GSD%20format%29&amp;amp;hydrometeors=false&amp;amp;start=latest&quot; rel=&quot;noreferrer&quot;&gt;GSD file&lt;/a&gt; which doesn't seem to follow &lt;a href=&quot;https://rucsoundings.noaa.gov/raob_format.html&quot; rel=&quot;noreferrer&quot;&gt;NOAA's own file format&lt;/a&gt;. And it looks like HRRR comes in a &lt;em&gt;grib2&lt;/em&gt; format, which also doesn't seem to be as simple as &lt;code&gt;lat/lon,altitude,temp&lt;/code&gt;. It seems like these files provide something more raw which then needs to be simulated against to get the temps? I found some python libraries, but could use a pointer on the approach I need to take.&lt;/p&gt;&#xA;" OwnerUserId="18417" LastActivityDate="2019-12-10T08:29:39.367" Title="Where to get temperature sounding model forecast data?" Tags="|meteorology|weather-forecasting|atmosphere-modelling|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18617" PostTypeId="2" ParentId="18616" CreationDate="2019-12-03T07:30:44.293" Score="3" Body="&lt;p&gt;The GSD file is just a text (ASCII) file, which you can read with almost anything you want. Since you are using python I would recommend looking at Pandas and especially the &lt;a href=&quot;https://pandas.pydata.org/pandas-docs/stable/reference/api/pandas.read_csv.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;pandas.read_csv&lt;/a&gt; functionality.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am using this URL as an example now:&#xA;&lt;a href=&quot;https://rucsoundings.noaa.gov/get_soundings.cgi?data_source=Op40&amp;amp;latest=latest&amp;amp;start_year=2019&amp;amp;start_month_name=Dec&amp;amp;start_mday=3&amp;amp;start_hour=7&amp;amp;start_min=0&amp;amp;n_hrs=1.0&amp;amp;fcst_len=shortest&amp;amp;airport=50%2C-90&amp;amp;text=Ascii%20text%20%28GSD%20format%29&amp;amp;hydrometeors=false&amp;amp;start=latest&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://rucsoundings.noaa.gov/get_soundings.cgi?data_source=Op40&amp;amp;latest=latest&amp;amp;start_year=2019&amp;amp;start_month_name=Dec&amp;amp;start_mday=3&amp;amp;start_hour=7&amp;amp;start_min=0&amp;amp;n_hrs=1.0&amp;amp;fcst_len=shortest&amp;amp;airport=50%2C-90&amp;amp;text=Ascii%20text%20%28GSD%20format%29&amp;amp;hydrometeors=false&amp;amp;start=latest&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the &lt;a href=&quot;https://rucsoundings.noaa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ruc soundings&lt;/a&gt; you referred to. Here I just entered lat=50 and lon=-90 to pick something. You see this in the URL in &quot;airport=&quot;.&#xA;You can download the data you need with wget or curl and put into a file with a better name (sounding.txt) like this:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;wget &quot;https://rucsoundings.noaa.gov/get_soundings.cgi?data_source=Op40&amp;amp;latest=latest&amp;amp;start_year=2019&amp;amp;start_month_name=Dec&amp;amp;start_mday=3&amp;amp;start_hour=7&amp;amp;start_min=0&amp;amp;n_hrs=1.0&amp;amp;fcst_len=shortest&amp;amp;airport=50%2C-90&amp;amp;text=Ascii%20text%20%28GSD%20format%29&amp;amp;hydrometeors=false&amp;amp;start=latest&quot; -O sounding.txt&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Then you can write a small python program to fetch the data you need and read the data with pandas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also want to note that if you are going to use grib2 you will be able to easily change the model since grib2 is a standard format for NWP data. This will be a little more complicated, as it is a bit more tricky to read. grib2 is a binary format that is very good for storing large datasets. I refer to &lt;a href=&quot;https://confluence.ecmwf.int/display/ECC&quot; rel=&quot;nofollow noreferrer&quot;&gt;eccodes&lt;/a&gt; from ECMWF if you want to look more into this.&lt;/p&gt;&#xA;" OwnerUserId="17522" LastActivityDate="2019-12-03T07:30:44.293" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18618" PostTypeId="1" CreationDate="2019-12-03T13:15:10.433" Score="3" ViewCount="491" Body="&lt;p&gt;I am trying to initialize my model with the cloud liquid water data from ERA5. My model IITM-ESM which evolved from CFSv2 takes in the cloud liquid water information in &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{kg/m^2}$&lt;/span&gt;. However the ERA5 specific cloud liquid water data is in kg/kg. I have the following questions&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Am I right in trying to derive cloud liquid water in &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{kg/m^2}$&lt;/span&gt; for specific cloud liquid water in kg/kg&lt;/li&gt;&#xA;&lt;li&gt;How do I go about this ? I found a way to convert kg/kg cloud liquid water content to &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{g/m^3}$&lt;/span&gt; in the link &lt;a href=&quot;https://www.nwpsaf.eu/site/download/documentation/rtm/docs_rttov12/rttov_gas_cloud_aerosol_units.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nwpsaf.eu/site/download/documentation/rtm/docs_rttov12/rttov_gas_cloud_aerosol_units.pdf&lt;/a&gt;&#xA;After getting the cloud liquid water in &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{g/m^3}$&lt;/span&gt;, will multiplying by layer thickness (data is 3D with lat, lon, levels and the level information is in pressure levels i.e. Pascals) and &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{10^{-3}}$&lt;/span&gt; be okay to convert it to &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{kg/m^2}$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="18076" LastEditorUserId="2470" LastEditDate="2020-01-02T19:33:22.593" LastActivityDate="2020-01-02T19:37:03.007" Title="How to convert the units of specific cloud liquid water from ERA5 (kg/kg) to kg/m2?" Tags="|meteorology|numerical-modelling|atmospheric-circulation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18619" PostTypeId="2" ParentId="17969" CreationDate="2019-12-03T15:14:28.290" Score="0" Body="&lt;p&gt;A widely used and truly classical climate zone classification scheme is the &lt;a href=&quot;https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification&quot; rel=&quot;nofollow noreferrer&quot;&gt;Köppen climate classification&lt;/a&gt; one. The classification terms you mentioned can be found there.&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user20217" LastEditDate="2020-04-05T16:46:44.977" LastActivityDate="2020-04-05T16:46:44.977" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18621" PostTypeId="2" ParentId="18390" CreationDate="2019-12-03T18:18:52.123" Score="-1" Body="&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; levels in the lungs of a human can reach levels as high as 70,000 ppm under normal breathing while the concentration of our breath out is normally 40,000 ppm.  The numbers skyrocket well over 100,000 ppm when we exert ourselves or hold our breath.  To even suggest that an extra 200 ppm or even 1000 ppm of &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; in some way affects us is not likely.&lt;/p&gt;&#xA;" OwnerUserId="17129" LastEditorUserId="2470" LastEditDate="2020-01-04T19:09:31.857" LastActivityDate="2020-01-04T19:09:31.857" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18623" PostTypeId="1" AcceptedAnswerId="18624" CreationDate="2019-12-04T11:31:21.477" Score="1" ViewCount="62" Body="&lt;p&gt;The Catamaran &lt;a href=&quot;https://www.marinetraffic.com/en/ais/details/ships/shipid:4997037/mmsi:227497060/imo:0/vessel:LA_VAGABONDE&quot; rel=&quot;nofollow noreferrer&quot;&gt;La Vagabonde&lt;/a&gt; is a high tech vessel that's designed to be as carbon neutral as possible. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Subject to the constraints of space, time and safety, what citizen science projects would be possible on this vessel? &lt;/p&gt;&#xA;" OwnerUserId="17293" LastActivityDate="2019-12-04T14:50:41.263" Title="On La Vagabonde what Citizen Science is Possible?" Tags="|oceanography|science-fair-project|" AnswerCount="1" CommentCount="4" ClosedDate="2019-12-14T14:29:37.353" ContentLicense="CC BY-SA 4.0" />
  <row Id="18624" PostTypeId="2" ParentId="18623" CreationDate="2019-12-04T14:32:11.207" Score="2" Body="&lt;p&gt;Ok, trying an answer. I don't know if citizen science is actually done. Possible would be sample collection, physical data (water temperature, air temperature), weather conditions, sigthings of rubbish, animals or unusual phenomena. Actually, before the space age ships collected and exchanged weather data to produce on ship weather charts for example. Afaik, this is not practical any more, merchant ships anyway and increasingly recreational vessels (if the owner can afford) have satellite data and internet on board.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Data collection in itself is no problem, but the calibration to make them comparable and combinable is. In simple words, one can't just buy a thermometre and bind it to the mast, they'd differ by a lot. Recreative vessels have their routes on the oceans. In Atlantic terms, now (November) they set out in hundreds and thousands into the Caribbean, in spring some them return (the northern route is more strenuous ;-)). There is not that much to be had science wise because they all measure similar things (in between the sunbathing on their catamarans).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And, there actually is concern that too much citizen science could leave a negative carbon footprint.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Something to read: &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4159111/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4159111/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorUserId="1411" LastEditDate="2019-12-04T14:50:41.263" LastActivityDate="2019-12-04T14:50:41.263" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18625" PostTypeId="1" AcceptedAnswerId="18627" CreationDate="2019-12-04T17:42:49.517" Score="1" ViewCount="80" Body="&lt;p&gt;I live in Van, Turkey. Van City is situated on an alluvial plain beside Lake Van. General geological structure of the area can be seen on pages 43-44 in &lt;a href=&quot;http://www.dsi.gov.tr/docs/sempozyumlar/van-g%C3%B6l%C3%BC-hidrolojisi-ve-kirlili%C4%9Fi-konferans%C4%B1-van.pdf?sfvrsn=2&quot; rel=&quot;nofollow noreferrer&quot;&gt;this conference book&lt;/a&gt;. One of the images is below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0gFEm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0gFEm.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to the article in the link, sediment layers has a slope of 15-30 degrees toward the lake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With the construction of every building, the pressure over the sediments increases. Obviously, this increase is greater in downtown area which has a lot of apartment blocks (mainly 5 to 7 story high reinforced concrete buildings). Downtown area is roughly in the middle of the plain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to know that how much does the weight of urban structures (buildings) affect the compaction (permeability/porosity/density?) of alluvial sediments below a city and how does this affect the flow of underground water?&lt;/p&gt;&#xA;" OwnerUserId="13741" LastEditorUserId="2470" LastEditDate="2019-12-04T23:48:30.590" LastActivityDate="2019-12-05T00:49:17.273" Title="How much does the weight of urban structures (buildings) affect the compaction (permeability, porosity, density) of alluvial sediments below a city?" Tags="|sedimentology|groundwater|pressure|stress|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18626" PostTypeId="2" ParentId="18625" CreationDate="2019-12-04T23:32:06.500" Score="0" Body="&lt;p&gt;Heavy buildings can sometimes be supported by piles going down to the bedrock beneath, but a popular and cheaper solution nowadays is the use of piled-raft foundations. This consists of a slab of reinforced concrete covering the entire footprint of the building, thus spreading the load, and this slab (or raft) is supported by numerous concrete piles below it which do not go down to bedrock. Very small trickles of water underneath the structure are not a problem provided they are not trapped by it. Because the load is spread over a large area, the porosity of alluvial sediments below is little affected by the weight of the building.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-04T23:32:06.500" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18627" PostTypeId="2" ParentId="18625" CreationDate="2019-12-05T00:49:17.273" Score="2" Body="&lt;p&gt;This question might be more appropriate for the SE Engineering site.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The thing about soils is that they vary from place to place. Some are sandy, some contain more clay than others and the thicknesses of layers is also variable. All this influences how different soils react to surface loading stresses, such as from building foundations/footings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Immediately below the footings the soils will experience the greatest stress increases. As discussed in &lt;a href=&quot;https://people.eng.unimelb.edu.au/stsy/geomechanics_text/Ch3_Strs_Ground.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this document&lt;/a&gt;, particularly from page 10 onwards, the magnitude of stress the soil experiences from footings decreases with depth - see the effect of a point load &lt;span class=&quot;math-container&quot;&gt;$Q$&lt;/span&gt;, applied to the surface, on the upper right of page 12. At a depth &lt;span class=&quot;math-container&quot;&gt;$z$&lt;/span&gt;, the vertical stress &lt;span class=&quot;math-container&quot;&gt;$\sigma_v$&lt;/span&gt; has a certain higher value. At a depth of &lt;span class=&quot;math-container&quot;&gt;$2z$&lt;/span&gt;, the value of &lt;span class=&quot;math-container&quot;&gt;$\sigma_v$&lt;/span&gt; is lower.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One reason why the affect of surface loads decreases with depth is due to the nature of soil particles and how they lie in relation to each other. Soil particles are not uniform in size or shape, so they rarely lie directly on top of each other. There are gaps between soil particles, called pores. The pores can hold ground water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Compaction and consolidation of soils will reduce the volume (size) of pore spaces. Foundation loadings will only affect the soil beneath them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because soil particles do not lie directly on top of each other, one particle may lie above two or more particles, the stress exprienced by the upper soil particle will be transferred to the other particles. Providing the soil is deep enough, the affect of this is the to, over depth, transfer vertical stresses to horizontal stresses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ultimately, if a soil profile is deep enough, the stress the lower reaches of the soil experience due to urban development will be small and will not affect ground water movement.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2019-12-05T00:49:17.273" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18628" PostTypeId="2" ParentId="18618" CreationDate="2019-12-05T12:42:36.247" Score="2" Body="&lt;p&gt;I got the solution &lt;a href=&quot;https://www.researchgate.net/post/How_to_convert_the_units_of_specific_cloud_liquid_water_from_ERA5_kg_kg_to_kg_m2&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/post/How_to_convert_the_units_of_specific_cloud_liquid_water_from_ERA5_kg_kg_to_kg_m2&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nwpsaf.eu/site/download/documentation/rtm/docs_rttov12/rttov_gas_cloud_aerosol_units.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nwpsaf.eu/site/download/documentation/rtm/docs_rttov12/rttov_gas_cloud_aerosol_units.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the above link the conversions between &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{kg/kg}$&lt;/span&gt; , &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{g/m^3}$&lt;/span&gt; , &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{kg/m^2}$&lt;/span&gt; can be explicitly derived&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT&lt;/strong&gt;&#xA;The summary of the first hyperlink is:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{kg/kg}$&lt;/span&gt; stands usually for kg liquid water per kg air.&#xA;  Multiplying the term with the calculated air density within the field will result into &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{kg/m^3}$&lt;/span&gt;, which means kg liquid water per &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{m^3}$&lt;/span&gt; air. Then you have to multiply with the thickness of the liquid cloud, which will result into &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{kg/m^2}$&lt;/span&gt;.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="18076" LastEditorUserId="2470" LastEditDate="2020-01-02T19:37:03.007" LastActivityDate="2020-01-02T19:37:03.007" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18629" PostTypeId="1" AcceptedAnswerId="18630" CreationDate="2019-12-05T13:36:57.237" Score="4" ViewCount="177" Body="&lt;p&gt;I have downloaded ERA5 data and am trying to plot temperature variable. The problem I am facing is that even after providing a 2D area for plotting, ferret is giving an error saying that the region must be 2D &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;yes? fill t[k=1,l=1]&#xA; **ERROR: dimensions improperly specified: must be a 2D region&#xA;      CONTOUR/FILL t[k=1,l=1]&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="18429" LastActivityDate="2019-12-05T13:40:05.750" Title="Why is ferret giving me error that the region is not 2D while plotting" Tags="|reanalysis|era|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18630" PostTypeId="2" ParentId="18629" CreationDate="2019-12-05T13:40:05.750" Score="4" Body="&lt;p&gt;You need to use the following syntax&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;yes? fill 't'[k=1,l=1]&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;This is because ferret treats t variable name as time and to distinguish your variable name (if it is the same in the file), you have to provide it in double quotes.&lt;/p&gt;&#xA;" OwnerUserId="18076" LastActivityDate="2019-12-05T13:40:05.750" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18631" PostTypeId="2" ParentId="15992" CreationDate="2019-12-05T13:51:37.610" Score="1" Body="&lt;p&gt;This is more a problem with how you are trying to categorize things than any concrete problem. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A &quot;plate&quot; is not a completely hard and fast concept, there is some interpretation involved, it is a way of categorizing a group of natural objects with similar properties.  When continental crust merges they do not become homogeneous, much like how individual boards can be used to make a piece of furniture a continental plate can be made of many joined plates. Continental plates are one of those things that don't follow fine categorization well, continental plates can be composed of many smaller plates and the distinction between two plates can be vague. Generally once two plates are moving together they are treated as one, the definition of &quot;Plate&quot; much like the definition of species is one of those things can van vary quite bit depending on how it is being used. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most continental plates are built of many smaller plates that have become fused together, these pieces often become distinct &lt;a href=&quot;https://en.wikipedia.org/wiki/Geologic_province&quot; rel=&quot;nofollow noreferrer&quot;&gt;provinces&lt;/a&gt;within the plate. It is possible to reconstruct past individual past plates in many continental plates&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Imagine if you have two sheets of clay on a table, you can slide each piece around until you push them together with force, and the edges stick together, then they fuse into one large sheet and you can't move one without moving the other so you can safely treat them as one thing. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2019-12-05T13:51:37.610" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18632" PostTypeId="2" ParentId="17876" CreationDate="2019-12-05T17:19:10.373" Score="6" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Three-age_system&quot; rel=&quot;nofollow noreferrer&quot;&gt;partition&lt;/a&gt; in stone - bronze - iron is an early 19th century thing invented to explain to pupils the findings in north-western Europe. It has little modern day relevance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Paleolithic&lt;/strong&gt; (European ! Africa has a different chronology and the below is not generally applicable !) is a hand wavy container expression for anything from the first signs of human presence in Europe ~1.7my up to and including the last glacial maximum (lgm), and mostly refers to the life and strife of humans in the cold steppe. It encompasses different human species and subspecies, and in itself is divided into lower-, middel- (starting ~250,000) and upper paleolithic (~45,000) following stratigraphic expressions that what is above is regarded as being younger than what is below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On a high level, lower paleolithic (again: Europe !) is generally connected with the presence of Homo habilis and erectus and ante-neandertals (i am being a &quot;lumper&quot; here), the middle paleolithic is the time of the Neandertals (Homo sapiens neandertalensis), and the upper paleolithic deals with the likes of us, Homo sapiens sapiens. All these units have further subdivisions based on tool technology and -industry. As an example, the upper paleolithic is further subdivided in (old to young) Aurignacian, Gravettian, Solutrean (around the lgm) and Magdalenian with their respective clearly distintctive stone and bone tool industries, and these have further local or regional expressions that deserve more detailed description.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With the onset of re-forestation human subsistance changes funtamentally. This is the time of the hunters and gatherers of the forests, the &lt;strong&gt;Mesolithic&lt;/strong&gt; period in Europe, a relatively short period broadly taking place between ~9000 and 5500 BC. It lasts until and partly side by side with the incoming &lt;strong&gt;Neolitihic&lt;/strong&gt;, the revolutionary (but not abrupt) change to farming, animal husbandry and settledness. The latter started over a few thousand years in Anatolia/Fertile Crescent/Levant between 11000 and 8000 BC (simplifying here for the sake of brevity).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then it gets complicated. Metal (copper) has already been in use since in the Neolithic (see Chalcolithic), use of &lt;strong&gt;bronze&lt;/strong&gt; starts in the middle east ~3200BC, and spreads north, arriving in central Europe around 2200BC. But it is not used everywhere (example: Egypt). Use of &lt;strong&gt;iron&lt;/strong&gt; starts ~1200BC, arriving in central Europe ~800BC. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please keep in mind that there are huge regional or local differences with their respective own chronologies, because human subsistance and so the use of tools has never been uniform.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding &lt;strong&gt;humans&lt;/strong&gt;: We can speak of &quot;humans&quot; and the genus Homo with the onset of tool making ~2.6My ago, Oldovan stone tool technology in East Africa, though in these times there is not always and generally a link between a human species and a certain stone tool industry. The case of human speciation is complicated, and got even more so with the use (ancient) genetics as a tool for analysis. Though the latter is still a developin science, it looks like there have always been multiple species or subspecies around until recently. Today there is only one human species remaining on earth, and it is unclear how long they'll make it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pls. let me suggest to search the Biology departement here (or elsewhere) for an up-to-data primer on human species and subspecies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ok, questions ? :-)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: since the original question has been clarified, i'd like to add something. First, there is no such thing as a single step that defines what an anatomically modern human (amh) really is. Evolution does not jump ! It is a gradual process of speciation, of adaptation to a niche. It may take place in a limited geographical region if individuals don't move far or over a large aerea, even over continetal limits if individuals or groups move in an out. As that's what humans did, things aren't exactly simple and in constant flow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Find places of early amhs show that they developed, just like other humans before, in Afrcia, but rather distributed than in a single spot. &lt;a href=&quot;https://www.nature.com/articles/nature22336&quot; rel=&quot;nofollow noreferrer&quot;&gt;Jebel Irhoud&lt;/a&gt; is up to now the oldest specimen with traits of amh, for the splitters among us in the field between h. heidelbergensis, rhodesiensis, neandertalensis, sapiens ...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But there is maybe another thing to your question, which is called &quot;behavioural modernity&quot;. People using personal adornement, creating art objects like figurines, paintings of scenes from real life or more abstract symbols on cave walls, carving and painting mussels, etc. For a long time this was attributed to amh in Europe alone, starting with the arrival of the first groups of modern humans ~45,000 years ago. But recently, this was questioned, with the findings of traces from Neandertal find sites hinting to abstract thinking much earlier, 65,000BC in Gibraltar (Gorham Cave) and &lt;a href=&quot;https://advances.sciencemag.org/content/4/2/eaar5255&quot; rel=&quot;nofollow noreferrer&quot;&gt;115,000&lt;/a&gt; in southern Spain. So, from a cultural point of view, there is no real &quot;unique feature&quot; in favour of amh any more, the differences are floating, not &quot;carved in stone&quot; (haha).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is all in flow and debated. There'll surely be more news on all this soon (tm).&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user18411" LastEditDate="2019-12-06T11:02:44.710" LastActivityDate="2019-12-06T11:02:44.710" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18634" PostTypeId="1" AcceptedAnswerId="18642" CreationDate="2019-12-06T03:16:08.543" Score="24" ViewCount="7507" Body="&lt;p&gt;I am wondering if there are any theories about the formation of oases, and I am also curious about why an oasis can even last for a very long period of time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have heard that fresh water exists on the surface of the desert because of a difference in elevation of the desert, causing the underground water to pop up. Is it the reason why oases exists? &lt;/p&gt;&#xA;" OwnerUserId="18431" LastEditorUserId="18431" LastEditDate="2019-12-09T02:39:06.113" LastActivityDate="2019-12-09T02:39:06.113" Title="How do oases form in the middle of the desert?" Tags="|hydrology|geography|desert|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18635" PostTypeId="1" CreationDate="2019-12-06T04:04:50.413" Score="2" ViewCount="348" Body="&lt;p&gt;According to the YouTube video &lt;a href=&quot;https://www.youtube.com/watch?v=w8eIcPDlHJY&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rip Currents: How to Survive the Deadliest Ocean's Trick&lt;/a&gt;, a rip current occurs when there are two circles of water spinning close to shore in opposite directions such that the water between them is flowing away from shore. My question is&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Is it possible to put yourself in a position where you're inside a spinning circle of water associated with a rip current and there's no way to escape from it without swimming underwater until you're rescued?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I don't know if that's possible or not. Maybe the water on the surface in a spinning circle is flowing around the circle and towards its centre and the water below the surface is flowing away from the centre. I won't get into the question about whether it's possible to escape the circle by swimming underwater. I think in that situation, the best thing is to swim directly away from the centre and not to swim against the current and let yourself keep being dragged around in circles. Even if you do that, the rate that water is flowing towards the centre might still be too fast. This is pretty much a yes no question so I think it should be easy to provide an answer that actually answers my question. Researchers might then be able to use the answer to invest in research on the best strategy to escape from a rip current.&lt;/p&gt;&#xA;" OwnerUserId="4846" LastEditorUserId="4846" LastEditDate="2019-12-06T17:54:58.447" LastActivityDate="2019-12-06T20:38:17.103" Title="Is it possible to get trapped in a circle of water in a rip current?" Tags="|ocean-currents|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18636" PostTypeId="2" ParentId="18634" CreationDate="2019-12-06T04:52:37.567" Score="14" Body="&lt;p&gt;There are two types of &lt;a href=&quot;https://en.wikipedia.org/wiki/Oasis&quot; rel=&quot;noreferrer&quot;&gt;oases&lt;/a&gt;: natural and human made.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Natural oases form when &lt;a href=&quot;https://en.wikipedia.org/wiki/Spring_(hydrology)&quot; rel=&quot;noreferrer&quot;&gt;springs&lt;/a&gt;, created when underground &lt;a href=&quot;https://en.wikipedia.org/wiki/Aquifer&quot; rel=&quot;noreferrer&quot;&gt;aquifers&lt;/a&gt; allow fresh water to pool or flow on the ground surface of &lt;a href=&quot;https://en.wikipedia.org/wiki/Desert&quot; rel=&quot;noreferrer&quot;&gt;deserts&lt;/a&gt;, creating a fertile region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A human made &lt;a href=&quot;https://www.nationalgeographic.org/encyclopedia/oasis/&quot; rel=&quot;noreferrer&quot;&gt;oasis&lt;/a&gt; occurs when humans create fertile region in a dry or &lt;a href=&quot;https://en.wikipedia.org/wiki/Arid&quot; rel=&quot;noreferrer&quot;&gt;arid&lt;/a&gt; region, such as a desert. The supply of water in human made oases is from underground water supplied by human made &lt;a href=&quot;https://en.wikipedia.org/wiki/Well&quot; rel=&quot;noreferrer&quot;&gt;wells&lt;/a&gt; or water bores. Because wind-blown desert sands can damage or destroy wells, sturdy trees (such as palm trees) are planted around the periphery of the oases. &lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="6467" LastEditDate="2019-12-06T14:40:19.833" LastActivityDate="2019-12-06T14:40:19.833" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18637" PostTypeId="2" ParentId="10695" CreationDate="2019-12-06T05:05:29.207" Score="2" Body="&lt;p&gt;In the Arduino compatible sensors I've found, CO, methane, and other common raw sensors are as little as US\$1 from China. The cheapest &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; sensor (also from China) I found was around US\$35.  Otherwise, raw sensors components are around US\$100.  The only real difference between the raw sensors and scientific instruments are that the instruments are obviously finished units that are certified and calibrated, like (for example) are raw Geiger tubes (US\$5) vs calibrated and certified Geiger counters (US$300). I have several DIY Geiger counters (US\$35) and calibrated Geiger counter instruments.&lt;/p&gt;&#xA;" OwnerUserId="18432" LastEditorUserId="2470" LastEditDate="2020-01-02T19:00:02.543" LastActivityDate="2020-01-02T19:00:02.543" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18638" PostTypeId="2" ParentId="18635" CreationDate="2019-12-06T09:38:26.417" Score="-2" Body="&lt;p&gt;Yes, it is possible to get trapped in a rip current, particularly if you are a weak swimmer. There are so many variables, e.g. speed of current, ability of the swimmer, his position in the current when he realises he is caught, and so on. It is impossible to recommend one escape technique which fits all situations. Don't try swimming underwater, that would be very dangerous. You will need all your breath and reserves of strength to keep you moving on the surface. Try to keep a cool head and not to panic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are a strong swimmer and the rip current is only one or two knots, then a sprint for the shore against the current will very likely succeed, but if you find you are making no headway and becoming tired, better to go with the flow. There is no way of judging the speed of the current until you pit yourself against it. For a weak swimmer, this will be very alarming, so he should concentrate on keeping afloat and let the current carry him in a circle. With luck, the people on the shore will organise a rescue. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the current has carried you right around and you find yourself approaching the shore, it would probably be worth making an attempt, this time with the current instead of against it, to sprint for the shore. There are sometimes notices on the shore warning against dangerous currents. Read these notices before going into the water.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-06T09:38:26.417" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18639" PostTypeId="2" ParentId="15302" CreationDate="2019-12-06T10:53:27.840" Score="2" Body="&lt;p&gt;I'll try to answer your second question using the &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/search/&quot; rel=&quot;nofollow noreferrer&quot;&gt;earthquake catalog&lt;/a&gt; of the USGS. I encourage you to run your own queries, it's pretty fun and easy to use!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UkTgW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UkTgW.jpg&quot; alt=&quot;Map of 6+ earthquakes around Indonesia since 2000&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is a result of a query for 6+ magnitude earthquakes, starting from 2000, centered around the indonesian archipelago. There is a total of 435 events in the region during this period of time. Now you can download the list as a csv file and have a look at it to get some statistics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0iofv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0iofv.png&quot; alt=&quot;Number of 6+ earthquakes per year&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you sort the events by year, you'll see that there are between 11 (in 2017) and 35 (in 2007) events per year, with a mean of 21.75 events per year. It's hard to get a clear tendency from this graph, although it seems that there was a decrease in activity in the 2011-2018 period.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ncohC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ncohC.png&quot; alt=&quot;Number of 6+ earthquakes per year&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It gets clearer if you look only at 7+ earthquakes. In this period there are 54 events in the region, but you can see that the vast majority happened in the 2000's, culminating in 2010 with 8 events. Then there is the only year without a 7+ event (2011), and five years in a row with only one event per year. From this graph it also seems that there is an increase in the last two years, with already 3 events in 2019, but I would be careful interpreting this: we lack perspective, and 54 is quite a low number to do a statistically robust analysis.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So from this I'd say there might be an increased seismic activity in the region, although it's too soon to tell for sure. Only time will tell, unfortunately.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: The first question is beyond my competence. It is known that earthquakes redistribute the stress in the lithosphere (see the review by &lt;a href=&quot;https://doi.org/10.1002/2017JB014617&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hardebeck &amp;amp; Okada, 2018&lt;/a&gt;). But the tectonic setting is really complicated in Indonesia, with lots of small plates and some unique features, like the divergent double subduction in the Molucca sea (&lt;a href=&quot;https://doi.org/10.1002/2017JB013991&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zhang et al., 2017&lt;/a&gt;)... So it's hard to tell if an earthquake here could trigger an earthquake there by modifying the regional stress field.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2019-12-06T15:09:57.160" LastActivityDate="2019-12-06T15:09:57.160" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18640" PostTypeId="2" ParentId="15302" CreationDate="2019-12-06T11:07:07.003" Score="-1" Body="&lt;p&gt;The Indonesian (Malay) archipelago is a huge chain of islands, several thousand miles in length from the northern tip of Sumatra to the south eastern extremity in New Guinea, so the 600 miles you mention between epicentres is nothing very much.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, the earthquakes are related, but there is no particular increase in seismic activity, it's normal for Indonesia. The earthquakes are random. The ones you mention are caused by the convergence of the Indo-Australian plate with the Eurasian plate to the north east. The plate margins loop around north-eastward, fairly close to the southern coast of Sulawesi The margin of the Indo-Australian plate is being subducted beneath the Eurasian plate and oceanic plate margin is being forced down into the mantle, where friction with the Eurasian plate above and the water content of the subducted zone cause partial melting of the rock. Rock is more easily melted where it has a high water content.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plumes of magma from the melted rock, being lighter than the mantle, rise to the surface where they erupt as volcanoes. Some earthquakes are caused by volcanism, but the major ones are caused by friction between the plates. Movement of a plate is temporarily held up at a particular point and stress builds up until it can be resisted no more. The sudden release of pent up energy is manifested as an earthquake. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-06T11:07:07.003" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18641" PostTypeId="2" ParentId="10695" CreationDate="2019-12-06T14:30:56.460" Score="7" Body="&lt;h2&gt;Carbon monoxide (CO), natural gas &amp;amp; hydrocarbons, VOCs, ammonia, etc.&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;In &lt;a href=&quot;https://chemistry.stackexchange.com/a/118050/16035&quot;&gt;this Chemistry SE answer&lt;/a&gt; and &lt;a href=&quot;https://electronics.stackexchange.com/q/302225/102305&quot;&gt;this Electronics SE question&lt;/a&gt; I discuss how the family of MOS gas sensors work. They can measure a large variety of different gasses that can react with atomic oxygen (O rather than &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{O_2}$&lt;/span&gt;). &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I'll quote from &lt;a href=&quot;https://electronics.stackexchange.com/q/302225/102305&quot;&gt;this question&lt;/a&gt;:&lt;/p&gt;&#xA;  &#xA;  &lt;blockquote&gt;&#xA;    &lt;p&gt;...sintered composite based on the semiconductor material &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{SnO_2}$&lt;/span&gt;, which is the metal oxide. The different sensors have different admixtures and operating conditions to achieve different sensitivities to different gasses. &lt;/p&gt;&#xA;    &#xA;    &lt;p&gt;The principle of operation of MOS-type gas sensors is explained in Figaro sensors' &lt;a href=&quot;http://www.figaro.co.jp/en/technicalinfo/principle/mos-type.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Operating principle; MOS type&lt;/a&gt;.&lt;/p&gt;&#xA;  &lt;/blockquote&gt;&#xA;  &#xA;  &lt;p&gt;The Figaro link shows the operating principle in the GIF below:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/qH4H5.gif&quot; alt=&quot;enter image description here&quot;&gt; GIF (Source: &lt;a href=&quot;https://www.figaro.co.jp/en/technicalinfo/principle/mos-type.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Figaro&lt;/a&gt;)&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;When the &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{SnO_2}$&lt;/span&gt; is heated by the (usually 5V but not always) heater supply, oxygen in the air will dissociate at the surface and oxygen ions will stick to the surface, depleting the semiconductor and cutting off the flow of current. When a carbon-containing gas (e.g. &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO}$&lt;/span&gt; or &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{C_xH_y}$&lt;/span&gt; (but not &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;)) comes along, it will combine with the adsorbed oxygen and remove it from the surface. The more gas, the lower the equilibrium concentration of adsorbed oxygen and the higher resulting current flow through the semiconductor. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;h2&gt;Carbon dioxide (&lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;)&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;The &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; sensor works on a totally different principle because &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; is fully oxidized carbon, it will not react further with atomic oxygen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Instead the &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; sensors are either solid electrolyte chemical cells like the MG-811 or newer versions (see &lt;a href=&quot;https://chemistry.stackexchange.com/q/89726/16035&quot;&gt;this question&lt;/a&gt;) or they are &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_dioxide_sensor#Nondispersive_Infrared_(NDIR)_CO2_Sensors&quot; rel=&quot;nofollow noreferrer&quot;&gt;Non-dispersive Infrared Light sensors (NDIRs)&lt;/a&gt; based on optical absorption of a certain wavelength of infrared light, using a hot filament or other light source to produce IR and a narrow multilayer optical filter to select one of the strong absorption lines of &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;. The more &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt;, the more the reduction in the transmission of light in the optical path of the sensor. &lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="2470" LastEditDate="2020-01-02T19:10:46.737" LastActivityDate="2020-01-02T19:10:46.737" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18642" PostTypeId="2" ParentId="18634" CreationDate="2019-12-06T15:56:42.247" Score="31" Body="&lt;p&gt;Oasis are places where aquifers are connected to the surface. The source of the water in the aquifer however can be hundreds of miles away in areas that do get significant rainfall. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The trick is geologic strat have different properties; some allow water to flow easily, others are very water tight, a water accessible layer covered by a water proof layer creates a aquifer. Faults or erosion can breach this water seal allowing to water to the surface, as can human wells. Recharge areas are places at higher elevation where water can enter the aquifer and flow downhill, they can be hundreds of miles away and are often in the mountains which often get much higher rainfall.  A picture is worth a thousand words. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jqJgX.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jqJgX.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2019-12-06T20:57:34.157" LastActivityDate="2019-12-06T20:57:34.157" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18643" PostTypeId="2" ParentId="18635" CreationDate="2019-12-06T18:36:30.170" Score="1" Body="&lt;p&gt;Ok, i try an answer based on your clarification.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Diving in a straight line in such a regime is near impossible, because sight is obstructed. A specially trained free diver may have more of a chance but will have to go to the surface several times.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now let's assume that an unlucky swimmer finds him-/herself in exactly the depicted situation and quickly analyzes and realizes what's going on (unlikely). If they are cold blooded enbough they can try and swim to one side, then with the stream either once around or back again towards the beach. But ... things aren't usually like in a picture book. There are coast parallel streams, waves and rocks can make it difficult to get out of the water unhurt, and maybe the stream turns too far outside or not at all. There may be undertow or a breaking wave throws the swimmer on the rocks. And when outside, even in 20° warm water the survival chances are low, until a helicopter or the rescue boat arrive. And even then, finding a head of a swimmer between the waves is pure luck for the rescue forces. People have actually drowned in the middle of regattas and dense trafic searching for them. That is why it is strictly forbidden to go overboard ;-)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a reason why people do die in such or similar situations. In any case, the answer to your question is &quot;Yes&quot;, a swimmer can easily find himself in a situation where reaching the land is impossible. A snorkler with fins may have better chances.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: just so that you know what i am talking about, 3 random videos. &lt;a href=&quot;https://www.youtube.com/watch?v=2HhKuJKGXpM&quot; rel=&quot;nofollow noreferrer&quot;&gt;Medium&lt;/a&gt; conditions, waves 1-2m. &lt;a href=&quot;https://www.youtube.com/watch?v=6nudt0F6_M8&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dynamic&lt;/a&gt; conditions, waves 6-8m. &lt;a href=&quot;https://www.youtube.com/watch?v=SxuKmPzAVvs&quot; rel=&quot;nofollow noreferrer&quot;&gt;Calm&lt;/a&gt; conditions, .5m waves. &lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user18411" LastEditDate="2019-12-06T20:38:17.103" LastActivityDate="2019-12-06T20:38:17.103" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18644" PostTypeId="2" ParentId="17317" CreationDate="2019-12-06T21:26:51.420" Score="0" Body="&lt;p&gt;1.5° to 3° can be linked to anthropogenic global warming.&#xA;&lt;a href=&quot;https://www.worldweatherattribution.org/wp-content/uploads/July2019heatwave.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.worldweatherattribution.org/wp-content/uploads/July2019heatwave.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This one, and others before, would not have been possible to that degree without anthopogenic heating. The desert is not to blame, they actually have, as has been said, a pretty high albedo and clear skies. During the day it gets hot because insolation, but during night the heat is qickly radiated out into space. There can be a hefty diurnal temperature range at the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A a general rule in meteorology, the air cannot go into the ground. It is only the surface that is directly exposed to and heated by the sun during day. At 10cm depth already (in a mobile dune) the temperature plays a minor role. &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2013JF002839&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2013JF002839&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, no, deserts are no natural convection heaters. The Sahara air actually suppresses convection frequently forming rock stable inversions. Some deserts are extreme coolers (Gobi, Antarctica, Greenland's dwindling ice sheet, ice covered mountain tops) due to their high albedo and radiation of the daily received insolation out into space. Changing albedo (e.g. by thawing) exposes more heatable surface to the sun, leading to a runaway feedback.&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user18411" LastEditDate="2019-12-07T12:10:17.313" LastActivityDate="2019-12-07T12:10:17.313" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18646" PostTypeId="1" CreationDate="2019-12-07T07:46:16.400" Score="1" ViewCount="101" Body="&lt;p&gt;I had an idea to make green islands from mid-pacific plastic: Release a million tons of floating iron balls there, which will stay in the same regions as the plastic and hopefully cause a veritable forest to grow on the plastic, especially if they contain a bit of nitrogen/phosphorus/silica to start the forest, and then seabirds and fish can hopefully do the rest.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What would happen to the iron balls, would they stay with the plastic islands, would they end up on beaches and be a waste of time? &lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2019-12-07T07:53:19.080" LastActivityDate="2019-12-07T08:54:14.240" Title="Result of floating-iron-balls in the mid-pacific?" Tags="|oceanography|pollution|biomass|plastic|pacific|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18647" PostTypeId="2" ParentId="18646" CreationDate="2019-12-07T08:54:14.240" Score="2" Body="&lt;p&gt;I take it that your iron balls are hollow and made of rust resistant steel. It would be a fiendishly expensive project, but I doubt it would have the result you suggest. The iron balls would have to be linked together by chain or rope to prevent them dispersing in ocean currents and ending up on beaches around the world, like the cargo of plastic ducks which fell overboard from a ship about ten years ago. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Such a contrivance would represent a hazard to shipping, so no government would be willing to spend the huge amount of money it would cost. The whole thing would probably end up on the beach of some Pacific island and cost a fortune to remove.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem of plastic in the ocean is certainly a serious one, and something needs to be done about it, but this is not the solution. Perhaps an internationally financed ship dedicated to seeking out rafts of plastic at sea and disposing of them might help, and would certainly be much cheaper and easier to control than your million tons of iron balls.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A world-wide educational campaign aimed at teaching people the damage caused by dumping their rubbish on beaches, in rivers, and from ships might have some effect in reducing the amount of rubbish which ends up in the sea. I always use an ordinary plastic shopping bag a couple of dozen times before it starts to fall to pieces, and then I put it in a bin bag to go to landfill. If everyone did the same it would be a major step in the right direction. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-07T08:54:14.240" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18648" PostTypeId="1" CreationDate="2019-12-07T14:54:50.380" Score="3" ViewCount="102" Body="&lt;p&gt;I have been exploring the sandstone of southern Utah for many years and I have a question about the area around Sidestep Canyon (near Wahweap, near Page, AZ). There are many amazing hoodoos there and they are Entrada under Dakota. Morrison and Summerville are totally missing. Here are some hoodoos in the white Entrada under the red Dakota &lt;a href=&quot;https://i.stack.imgur.com/Jrzm6.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Jrzm6.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question concerns this pic.  &lt;a href=&quot;https://i.stack.imgur.com/7wxGT.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7wxGT.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a small piece of Dakota at left foreground. But on the cliff there is an alternating red and white band. This is reminiscent of the wedding cake parts of the Summerville, which in general is totally missing here. Could this be Summerville? More likely it is either a mix of Entrada or Dakota, or maybe just some reddish Entrada interwoven with the white. It forms a much steeper cliff than the surrounding terrain, so I assume the red layer is less prone to erosion.  Any comments welcome.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Stan Wagon &lt;/p&gt;&#xA;" OwnerUserId="18439" LastEditorUserId="18439" LastEditDate="2019-12-07T17:29:22.677" LastActivityDate="2019-12-07T17:29:22.677" Title="Sandstone Layer Question" Tags="|sedimentology|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18650" PostTypeId="1" CreationDate="2019-12-08T01:52:21.380" Score="2" ViewCount="262" Body="&lt;p&gt;Why do some heavy rainstorms and hailstorms not produce any lightning or thunder at all when I thought that these conditions of heavy rain and hail are right to bring lightning and thunder but don’t and why some tornadoes don’t produced lightning or thunder when the conditions are right for lightning and thunder to form?&lt;/p&gt;&#xA;" OwnerUserId="17923" LastActivityDate="2022-01-04T03:06:45.593" Title="Conditions of Thunderstorms" Tags="|thunderstorm|rain|tornado|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18651" PostTypeId="2" ParentId="18650" CreationDate="2019-12-08T09:25:36.293" Score="1" Body="&lt;p&gt;For lightning to form there has to be a rising current of air within the cloud, carrying ice crystals and water droplets upwards. The droplets become hail, and start to fall as the air becomes thinner, rubbing some electrons off the minute ice crystals, which continue to rise, now positively charged. The soft hail falls to lower levels and is now negatively charged. Positive and negative charges have a great attraction for each other, as the electromagnetic force is almost unbelievably powerful.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Air is a bad conductor, so although the separated charges gradually build up they won't recombine until the build-up of charge is sufficiently strong to overcome the resistance of the air. Leaders from the oppositely charged regions are constantly probing for a viable passage where a lightning flash can get through to recombine their positive and negative charges.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sometimes a way is found where the build-up of charge is sufficiently strong to overcome air resistance and a lightning stroke occurs, but if the charge build up is not sufficiently strong no spectacular flash will occur. Instead, the separated charges gradually leak away until charge equilibrium is established. So although it may seem to you that conditions are right for lightning to occur, that may not actually be the case.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More unusually, separation of charge can also happen in dry conditions like dust storms and forest fires, where rising dust particles take the place of water. A vaguely similar process of charge separation takes place in a Van der Graaf generator, which can produce artificial miniature lightning discharges.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-08T09:25:36.293" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18652" PostTypeId="1" AcceptedAnswerId="18678" CreationDate="2019-12-08T11:38:44.107" Score="3" ViewCount="111" Body="&lt;p&gt;Heavy rain or flood events have recurrence intervalls. I.e. 100 year, 50 year or 25 year events. However, with increasing data and global warming and other factors these intervalls change. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How can I check wether a heavy rain event from 2015 with a recurrence intervall of 50 years still has the same intervall? Or wether it already has a 48 year intervall.  &lt;/p&gt;&#xA;" OwnerUserId="18169" LastActivityDate="2019-12-12T14:28:44.873" Title="How to check the recurrence intervall of heavy rain events" Tags="|hydrology|statistics|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18653" PostTypeId="2" ParentId="18013" CreationDate="2019-12-08T20:21:58.927" Score="0" Body="&lt;p&gt;Addressing is every volcano a mountain:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nope. Some are actually depressions called calderas, when they have erupted and the resulting emptying of the magma chamber caused the roof to collapse, or if they erupted only once, leaving behind a maar. Examples: Yellowstone, or Phlegrean fields are calderas, volcanic Eifel has &quot;Maare&quot; (German plural of Maar).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are shield volcanos, calderas, lava domes, ...&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user18411" LastEditDate="2019-12-08T20:29:30.790" LastActivityDate="2019-12-08T20:29:30.790" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18655" PostTypeId="1" CreationDate="2019-12-09T12:18:52.720" Score="4" ViewCount="108" Body="&lt;p&gt;Much of the Arctic Ocean is fairly shallow compared to other oceans. There must have been times in the past during severe ice ages that a lot of what is now the ocean bed was above sea level. When was the last time that most of the arctic Ocean floor was above sea level? Going back further, were there ever forests, peat bogs or coal deposits on the present day ocean floor, and when were the internationally coveted oil reserves formed?&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-12-09T14:20:24.457" LastActivityDate="2019-12-10T19:04:09.837" Title="History of the Arctic Ocean" Tags="|oceanography|sea-level|minerals|ice-age|oil-reserves|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18656" PostTypeId="1" CreationDate="2019-12-09T16:08:39.257" Score="1" ViewCount="72" Body="&lt;p&gt;The IPCC claims that the reflected radiation from incresaed CO&lt;sub&gt;2&lt;/sub&gt; heats the Earth at a rate of 5 W m&lt;sup&gt;-2&lt;/sup&gt;. How did the contributing researchers came out with that result?&lt;/p&gt;&#xA;" OwnerUserId="18454" LastEditorUserId="1411" LastEditDate="2019-12-09T16:23:56.307" LastActivityDate="2019-12-09T16:23:56.307" Title="Reflected radiation from increased CO2 : how was this calculated" Tags="|climate-change|climate|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18657" PostTypeId="1" AcceptedAnswerId="18658" CreationDate="2019-12-09T16:24:15.517" Score="2" ViewCount="1213" Body="&lt;p&gt;As stated in the title, I wonder how large the area covered by certain coordinates actually is, when they have the accuracy XX°YY'ZZ&quot;, for example:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;51°26'02&quot;N, 07°20'04&quot;E&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;How can this be calculated?&lt;/p&gt;&#xA;" OwnerUserId="18287" LastActivityDate="2019-12-11T15:13:16.687" Title="How large is the area covered by coordinates XX°YY'ZZ&quot;N/XX°YY'ZZ&quot;E?" Tags="|coordinate-system|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18658" PostTypeId="2" ParentId="18657" CreationDate="2019-12-09T16:53:22.250" Score="9" Body="&lt;p&gt;This is a coordinate, a single point. No area or distance can be calculated from that, sorry ...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Geographic_coordinate_system&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Geographic_coordinate_system&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The length of one arcsecond depends on the latitude. The Wikipedia article explains it quite well. Distances between two coordinates can be calculated via the &lt;a href=&quot;https://en.wikipedia.org/wiki/Great-circle_distance&quot; rel=&quot;noreferrer&quot;&gt;great circle distance&lt;/a&gt;. Calculating areas on earth's surface is more involved, since they require a &lt;a href=&quot;https://en.wikipedia.org/wiki/Map_projection&quot; rel=&quot;noreferrer&quot;&gt;projection&lt;/a&gt; into 2D.&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user18411" LastEditDate="2019-12-09T17:32:56.620" LastActivityDate="2019-12-09T17:32:56.620" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18659" PostTypeId="2" ParentId="18616" CreationDate="2019-12-09T17:06:38.317" Score="0" Body="&lt;p&gt;From what I see, for some reason the GSD has split the 't/td' column into two separate columns, and has multiplied the temperatures by 10. Why? Maybe to get rid of the decimal point... So when you see a value &amp;lt; -500 it's actually &amp;lt; -50 °C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HWgMo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HWgMo.png&quot; alt=&quot;Comparison between GSD and &amp;#39;get text&amp;#39;&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other changes:&lt;br&gt;&#xA;- Pressure and altitude have been switched.&lt;br&gt;&#xA;- Pressure has also been multiplied by 10, so it's not in millibars any more but in decapascals...&lt;br&gt;&#xA;- Altitude has been converted from feet ('get text' version) to meters (GSD).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To summarize, here are the inferred column headings for the GSD:&lt;br&gt;&#xA;&lt;strong&gt;| 2 Pressure (daPa) | 3 Altitude (m) | 4 t (d°C = decidegree Celcius) | 5 td (d°C) |&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know what to make of the &quot;99999&quot; temperature line that appeared in the GSD...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope you can make something out of this!&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2019-12-10T08:29:39.367" LastActivityDate="2019-12-10T08:29:39.367" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18660" PostTypeId="2" ParentId="18657" CreationDate="2019-12-09T19:06:52.570" Score="3" Body="&lt;p&gt;A point do not have an area. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;http://mathworld.wolfram.com/Point.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;A point is a 0-dimensional mathematical object which can be specified in &lt;em&gt;n&lt;/em&gt;-dimensional space using an &lt;em&gt;n&lt;/em&gt;-tuple (x&lt;sub&gt;1&lt;/sub&gt;, x&lt;sub&gt;2&lt;/sub&gt;, ..., x&lt;sub&gt;n&lt;/sub&gt;) consisting of &lt;em&gt;n&lt;/em&gt; coordinates.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The area of a point cannot be calculated. So the area must be null.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2019-12-09T19:06:52.570" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18661" PostTypeId="2" ParentId="12632" CreationDate="2019-12-09T22:31:22.400" Score="1" Body="&lt;p&gt;I live along the Missouri River near Jefferson City MO. I've lived here since 1983. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There has been a couple of times in the past where my town experienced blizzard like conditions where between 18 to 24 inches of heavy wet snow was dropped overnight.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These events were confined locally to the river valley. Go North or South and the amount of snow dropped off quickly. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;During both of those events we experienced thundersnow. &lt;/p&gt;&#xA;" OwnerUserId="18455" LastActivityDate="2019-12-09T22:31:22.400" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18662" PostTypeId="2" ParentId="18655" CreationDate="2019-12-10T02:26:58.020" Score="1" Body="&lt;p&gt;During glaciations, the shelves down to ~100m depth would have been above sea level, but they would have been covered by ice sheets.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/vC4SR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vC4SR.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://geology.com/articles/arctic-ocean-features/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geology.com&lt;/a&gt;&lt;br&gt;&#xA;The actual &quot;ocean floor&quot; would still be deep water.&#xA;There is a general explanation of the oil formation &lt;a href=&quot;https://www.livescience.com/66008-why-oil-in-arctic.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;https://www.scientificamerican.com/article/why-is-oil-usually-found/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, although they don't say when (or where the continents were when the sediments were deposited), and again, this is on the shelves, not the floor.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://mem.lyellcollection.org/content/35/1/1&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;An overview of the petroleum geology of the Arctic&quot;&lt;/a&gt; has:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OOfYr.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OOfYr.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;  Maps of palaeogeography of the Arctic based on Golonka's maps for the Late Devonian, the Middle Triassic, the Late Jurassic and the Middle Palaeogene, representing the times of deposition of some of the major Arctic source rocks&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2019-12-10T19:04:09.837" LastActivityDate="2019-12-10T19:04:09.837" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18663" PostTypeId="1" AcceptedAnswerId="18666" CreationDate="2019-12-10T08:05:40.203" Score="1" ViewCount="101" Body="&lt;p&gt;I am working on an experimental weather station that has a minimal set of sensors:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;GPS (which gives me the location, date and time);&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Thermometer (which gives me the air temperature);&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Barometer (which gives me atmospheric pressure);&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Rain Detector (which indicates if it is raining or not);&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Ultraviolet sensor (which gives me the intensity of UV rays)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Basically, the system reads all these sensors simultaneously, with a 5 minute interval between readings and sends the samples to a remote database.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it possible to use the history of this information to make some kind of weather forecast?&lt;/p&gt;&#xA;" OwnerUserId="18381" LastActivityDate="2019-12-11T02:46:12.900" Title="Weather Forecast" Tags="|meteorology|weather-forecasting|" AnswerCount="1" CommentCount="3" ClosedDate="2019-12-11T03:24:32.343" ContentLicense="CC BY-SA 4.0" />
  <row Id="18664" PostTypeId="1" AcceptedAnswerId="18665" CreationDate="2019-12-10T09:54:58.213" Score="8" ViewCount="522" Body="&lt;p&gt;I am learning ocean modelling and have started with MOM6. I needed guidance on where to start from and how to run the model on my local machine (Ubuntu) to perform various tasks such as regridding or creating initial conditions or maybe small runs which might not take much time.&lt;/p&gt;&#xA;" OwnerUserId="18429" LastActivityDate="2019-12-11T01:59:25.150" Title="How do I start with Modular Ocean Model version 6 i.e. MOM6 on my ubuntu linux machine?" Tags="|oceanography|ocean-models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18665" PostTypeId="2" ParentId="18664" CreationDate="2019-12-10T09:55:55.533" Score="7" Body="&lt;p&gt;You can follow the instructions I wrote at &lt;a href=&quot;https://medium.com/@manmeet20singh11/installing-mom6-on-ubuntu-57918a200293?sk%3D9961d6f8565659b05e007349c47568b7&amp;amp;sa=D&amp;amp;source=hangouts&amp;amp;ust=1576058141492000&amp;amp;usg=AFQjCNH74gi6j9XgT6I3509nb8Y0gtj4-Q&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://medium.com/@manmeet20singh11/installing-mom6-on-ubuntu-57918a200293?sk%3D9961d6f8565659b05e007349c47568b7&amp;amp;sa=D&amp;amp;source=hangouts&amp;amp;ust=1576058141492000&amp;amp;usg=AFQjCNH74gi6j9XgT6I3509nb8Y0gtj4-Q&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;code&gt;Installing MOM6 on Ubuntu&lt;/code&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Downloading the model and basic libraries&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Following &lt;a href=&quot;https://github.com/NOAA-GFDL/MOM6-examples/wiki/Installing-MOM6-in-a-virtual-machine-running-Ubuntu&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://github.com/NOAA-GFDL/MOM6-examples/wiki/Installing-MOM6-in-a-virtual-machine-running-Ubuntu&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And the video &lt;a href=&quot;https://www.youtube.com/watch?v=a5hKh8s_1b0&amp;amp;t=181s&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=a5hKh8s_1b0&amp;amp;t=181s&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;sudo apt-get install git tcsh pkg-config&#xA;sudo apt-get install gfortran&#xA;sudo apt-get install netcdf-bin libnetcdf-dev libnetcdff-dev&#xA;sudo apt-get install openmpi-bin libopenmpi-dev&#xA;sudo apt-get install libnetcdff-dev&#xA;git clone --recursive https://github.com/NOAA-GFDL/MOM6-examples demo&#xA;cd demo&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Open the file src/mkmf/templates/linux-gnu.mk and find the variable LIBS. Now in this file add the syntax&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;# Add -lnetcdff&#xA;LIBS += -lnetcdff&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Compiling&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now we are ready to start compiling and that we will do by going to &lt;a href=&quot;https://github.com/NOAA-GFDL/MOM6-examples/wiki/Getting-started#compiling-the-models&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://github.com/NOAA-GFDL/MOM6-examples/wiki/Getting-started#compiling-the-models&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The instructions are for setting up on an intel compiler so we have to do some editing on these commands because we are going to use gfortran which is GNUs fortran.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Make a directory to work to build the advanced libraries&#xA;&#xA;mkdir -p build/gnu/shared/repro/&#xA;cd  build/gnu/shared/repro/&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Next, we will run the mkmf list path tools and we are going to give it the relative path to FMS the source code&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;../../../../src/mkmf/bin/list_paths -l ../../../../src/FMS&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;So what you have done is populated this file &lt;strong&gt;path_names&lt;/strong&gt; with all these files and now we are going to run another mkmf tool and care of itself and we are going to specify the linux gnu template that we edited above and we are going to tell it to build FMS&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;../../../../src/mkmf/bin/mkmf -t ../../../../src/mkmf/templates/linux-gnu.mk -p libfms.a -c &quot;-Duse_libMPI -Duse_netCDF -DSPMD&quot; path_names&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;and that makes the Makefile&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally we can type&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;make NETCDF=3 REPRO=1 FC=mpif77 CC=mpicc  libfms.a -j&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;So that builds the lib FMS code which can be seen by&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;$ ls -l libfms.a &#xA;-rw-rw-r-- 1 manmeet manmeet 13863094 Dec 10 13:22 libfms.a&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Now we are going to go back and we will make a new set of folders ocean_only/repro&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cd ../../&#xA;mkdir -p ocean_only/repro&#xA;cd ocean_only/repro&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Now we are going to run the list paths command again and that is just down and this time we are going to provide the current directory as a possible supply of sorts and gauge you want to put some source files in here and thats the dot for, and then there is the relative path of source code for MOM6 and we are going to be linking a dynamic executable, so we are putting the dynamic directory out of the config source and we are building a set up using the solo drivers, the driver had a config source, and all of the source code under src is being used.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;../../../../src/mkmf/bin/list_paths ./ ../../../../src/MOM6/{config_src/dynamic,config_src/solo_driver,src/{*,*/*}}/&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;So this has made a path_names file again which is populated will all the MOM6 source code. Now we are going to run the mkmf tool again and this time the target there is MOM6 and we have to change the template again to the linux-gnu&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;../../../../src/mkmf/bin/mkmf -t ../../../../src/mkmf/templates/linux-gnu.mk -o '-I../../shared/repro' -p MOM6 -l '-L../../shared/repro -lfms' -c '-Duse_libMPI -Duse_netCDF -DSPMD' path_names&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;This will create the Makefile and now we can run the Makefile using a similar command but the target will be MOM6&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;make NETCDF=3 REPRO=1 FC=mpif77 CC=mpicc LD=mpif77 MOM6 -j&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Now we have the executable just called MOM6 and we will demonstrate that it works.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Going to the top of the directory and then to double_gyre&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cd ../../../../&#xA;cd ocean_only/double_gyre/&#xA;mpirun -n 1 ../../build/gnu/ocean_only/repro/MOM6&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;This is a simple 10 day test and will give something like this&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;$ mpirun -n 1 ../../build/gnu/ocean_only/repro/MOM6&#xA;NOTE: MPP_DOMAINS_SET_STACK_SIZE: stack size set to    32768.&#xA;&amp;amp;MPP_IO_NML&#xA; HEADER_BUFFER_VAL=      16384,&#xA; GLOBAL_FIELD_ON_ROOT_PE=T,&#xA; IO_CLOCKS_ON=F,&#xA; SHUFFLE=          0,&#xA; DEFLATE_LEVEL=         -1,&#xA; CF_COMPLIANCE=F,&#xA; /&#xA;NOTE: MPP_IO_SET_STACK_SIZE: stack size set to     131072.&#xA;NOTE: ======== Model being driven by MOM_driver ========&#xA;NOTE: callTree: o Program MOM_main, MOM_driver.F90&#xA;NOTE: open_param_file: MOM_input has been opened successfully.&#xA;NOTE: open_param_file: MOM_override has been opened successfully.&#xA; MOM domain decomposition&#xA;whalo =    4, ehalo =    4, shalo =    4, nhalo =    4&#xA;  X-AXIS =   44&#xA;  Y-AXIS =   40&#xA; MOMc domain decomposition&#xA;whalo =    2, ehalo =    2, shalo =    2, nhalo =    2&#xA;  X-AXIS =   22&#xA;  Y-AXIS =   20&#xA;NOTE: diag_manager_mod::diag_manager_init: prepend_date only supported when diag_manager_init is called with time_init present.&#xA; MOM domain decomposition&#xA;whalo =    4, ehalo =    4, shalo =    4, nhalo =    4&#xA;  X-AXIS =   44&#xA;  Y-AXIS =   40&#xA; MOM domain decomposition&#xA;whalo =    4, ehalo =    4, shalo =    4, nhalo =    4&#xA;  X-AXIS =   44&#xA;  Y-AXIS =   40WARNING: depth_list_setup: ./Depth_list.nc does not exist.  Creating a new file.WARNING: depth_list_setup: ./Depth_list.nc does not exist.  Creating a new file.MOM Day       0.000      0: En 1.423707E-13, MaxCFL  0.00000, Mass 5.288178268008E+18&#xA;    Total Energy: 4126F9E3C5B6FEAF  7.5288188616176497E+05&#xA;    Total Mass:   5.2881782680077681E+18, Change:   0.0000000000000000E+00 Error:  0.00000E+00 ( 0.0E+00)&#xA;MOM Day       1.000     72: En 4.580432E-06, MaxCFL  0.00023, Mass 5.288178268008E+18&#xA;    Total Energy: 42B607A80A83D4D0  2.4222139843540812E+13&#xA;    Total Mass:   5.2881782680077681E+18, Change:  -4.3787057037831573E+01 Error: -4.37871E+01 (-8.3E-18)&#xA;MOM Day       2.000    144: En 8.958206E-06, MaxCFL  0.00040, Mass 5.288178268008E+18&#xA;    Total Energy: 42C58AE533474153  4.7372590026370648E+13&#xA;    Total Mass:   5.2881782680077681E+18, Change:   4.0318344822758547E+00 Error:  4.03183E+00 ( 7.6E-19)&#xA;MOM Day       3.000    216: En 1.166708E-05, MaxCFL  0.00045, Mass 5.288178268008E+18&#xA;    Total Energy: 42CC0E8B5CE02C7F  6.1697586479192992E+13&#xA;    Total Mass:   5.2881782680077681E+18, Change:   3.7798219410031322E+01 Error:  3.77982E+01 ( 7.1E-18)&#xA;MOM Day       4.000    288: En 1.542296E-05, MaxCFL  0.00044, Mass 5.288178268008E+18&#xA;    Total Energy: 42D28B60D5891799  8.1559337444446391E+13&#xA;    Total Mass:   5.2881782680077681E+18, Change:  -5.3715335655123397E+01 Error: -5.37153E+01 (-1.0E-17)&#xA;MOM Day       5.000    360: En 1.826022E-05, MaxCFL  0.00053, Mass 5.288178268008E+18&#xA;    Total Energy: 42D5F4B97D5D13C3  9.6563312817231047E+13&#xA;    Total Mass:   5.2881782680077681E+18, Change:  -2.1099290705067006E+01 Error: -2.10993E+01 (-4.0E-18)&#xA;MOM Day       6.000    432: En 2.397431E-05, MaxCFL  0.00062, Mass 5.288178268008E+18&#xA;    Total Energy: 42DCD397A5E14CB5  1.2678043163166683E+14&#xA;    Total Mass:   5.2881782680077681E+18, Change:  -1.0757841703346941E+01 Error: -1.07578E+01 (-2.0E-18)&#xA;MOM Day       7.000    504: En 2.927962E-05, MaxCFL  0.00073, Mass 5.288178268008E+18&#xA;    Total Energy: 42E19A5109E607AC  1.5483585791186938E+14&#xA;    Total Mass:   5.2881782680077681E+18, Change:   4.6503600220410505E+01 Error:  4.65036E+01 ( 8.8E-18)&#xA;MOM Day       8.000    576: En 3.486441E-05, MaxCFL  0.00081, Mass 5.288178268008E+18&#xA;    Total Energy: 42E4F5D995BB3999  1.8436920009364478E+14&#xA;    Total Mass:   5.2881782680077681E+18, Change:   2.4524203108417453E+01 Error:  2.45242E+01 ( 4.6E-18)&#xA;MOM Day       9.000    648: En 4.195565E-05, MaxCFL  0.00090, Mass 5.288178268008E+18&#xA;    Total Energy: 42E9393C9CAC4D82  2.2186896584766006E+14&#xA;    Total Mass:   5.2881782680077681E+18, Change:  -2.0342624683786397E+01 Error: -2.03426E+01 (-3.8E-18)&#xA;MOM Day      10.000    720: En 4.604729E-05, MaxCFL  0.00100, Mass 5.288178268008E+18&#xA;    Total Energy: 42EBAEF71B9A7E17  2.4350627232664072E+14&#xA;    Total Mass:   5.2881782680077681E+18, Change:   2.2570880028229340E+01 Error:  2.25709E+01 ( 4.3E-18)FATAL: NETCDF ERROR: No such file or directory File=RESTART/MOM.res.ncFATAL: NETCDF ERROR: No such file or directory File=RESTART/MOM.res.nc--------------------------------------------------------------------------&#xA;MPI_ABORT was invoked on rank 0 in communicator MPI_COMM_WORLD &#xA;with errorcode 1.NOTE: invoking MPI_ABORT causes Open MPI to kill all MPI processes.&#xA;You may or may not see output from other processes, depending on&#xA;exactly when Open MPI kills them.&#xA;--------------------------------------------------------------------------&#xA;-------------------------------------------------------&#xA;Primary job  terminated normally, but 1 process returned&#xA;a non-zero exit code.. Per user-direction, the job has been aborted.&#xA;-------------------------------------------------------&#xA;--------------------------------------------------------------------------&#xA;mpirun detected that one or more processes exited with non-zero status, thus causing&#xA;the job to be terminated. The first process to do so was:Process name: [[19779,1],0]&#xA;  Exit code:    1&#xA;--------------------------------------------------------------------------&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Thus we will get an error when we haven’t created a restart. We will do that now&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;mkdir -p RESTART&#xA;mpirun -n 1 ../../build/gnu/ocean_only/repro/MOM6&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Next we will use two processors and we see that it runs faster now&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;mpirun -n 2../../build/gnu/ocean_only/repro/MOM6&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://github.com/NOAA-GFDL/MOM6-examples/wiki/Ubuntu-compiler-environment&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://github.com/NOAA-GFDL/MOM6-examples/wiki/Ubuntu-compiler-environment&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18076" LastEditorUserId="2470" LastEditDate="2019-12-11T01:59:25.150" LastActivityDate="2019-12-11T01:59:25.150" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18666" PostTypeId="2" ParentId="18663" CreationDate="2019-12-11T02:15:03.077" Score="2" Body="&lt;p&gt;As @Erik notes, the answer to your question is vacuously &quot;yes&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Digging a little deeper, we can break this into two questions:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Given the vast amount of weather data available (&lt;a href=&quot;http://opendata.stackexchange.com/questions/10154/sources-of-weather-data/10155&quot;&gt;http://opendata.stackexchange.com/questions/10154/sources-of-weather-data/10155&lt;/a&gt;), is it possible to find correlations (either linear or non-linear) between known data such as latitude, longitude, elevation, time, previous weather (temperature, pressure, etc) and current weather? Of course, your interest is in correlating present conditions to future conditions, but, since we're looking at existing data, this is the same as correlation past conditions to present conditions.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;If such correlations exist, can we use them to predict future weather?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The answer to the first question is definitely yes: there necessarily exists a mathematical function that will convert any finite amount of known data and past conditions to present conditions. However, this mathematical function may be extremely complicated and completely useless for future predictions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer to the second question is &quot;maybe&quot;. We can limit ourselves to &quot;simple&quot; correlations derived from a given set of data and then test our correlations against out of band data (ie, data not used to create the correlations), or, better still, to make and test actual predictions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since correlation doesn't imply causation and past performance doesn't imply future performance, there's no guarantee that this will work.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In some sense, the following questions ask essentially the same question: &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/18151/&quot;&gt;Deserts and Humidity&lt;/a&gt; &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/18158/&quot;&gt;Precipitation and Elevation&lt;/a&gt; &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/18591/&quot;&gt;Is there any link between the weekly human cycle and weather?&lt;/a&gt; (using weekday as an input variable) &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/18183/&quot;&gt;Local Weather Forecast (Self-Learning Algorithm)&lt;/a&gt; &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/3160/&quot;&gt;Statistical weather prediction&lt;/a&gt; &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/4480/&quot;&gt;Predicting school closures with historical weather prediction data?&lt;/a&gt; (using school closure as an output variable) &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/8716/&quot;&gt;How does elevation affect the amount of rainfall received?&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/18447/&quot;&gt;Predicting the weather in two months&lt;/a&gt; &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/16366/&quot;&gt;Weather forecast based on pressure, temperature and humidity only (for implementation in Arduino)&lt;/a&gt; (which notes the &quot;Zambretti algorithm&quot; (&lt;a href=&quot;https://en.wikipedia.org/wiki/Zambretti_Forecaster&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Zambretti_Forecaster&lt;/a&gt;) is one existing correlation/forecasting algorithm) &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/9306/&quot;&gt;Is it typically colder after a storm?&lt;/a&gt; &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;and probably a few others.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think this would make an interesting project, but I don't know to what extent anyone has pursued this. If anyone wants to pursue it more deeply, feel free to contact me directly (contact info in profile).&lt;/p&gt;&#xA;" OwnerDisplayName="user967" LastEditorDisplayName="user967" LastEditDate="2019-12-11T02:46:12.900" LastActivityDate="2019-12-11T02:46:12.900" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18667" PostTypeId="1" CreationDate="2019-12-11T04:24:35.380" Score="1" ViewCount="70" Body="&lt;p&gt;I am working on a small creek in Colorado using historical imagery via Google earth. I want to know if the imagery date at the bottom of each image on google earth is the date the google acquired the image. Or, is it the date the satellite recorded it? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I came across this blog post online (&lt;a href=&quot;https://www.quora.com/How-can-you-find-out-the-date-of-satellite-images-used-in-Google-Maps&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.quora.com/How-can-you-find-out-the-date-of-satellite-images-used-in-Google-Maps&lt;/a&gt;), which suggests that the two dates do not always match.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does google provide metadata for imagery? Please advice.&lt;/p&gt;&#xA;" OwnerUserId="14152" LastActivityDate="2019-12-11T04:24:35.380" Title="Google earth historical imagery date" Tags="|remote-sensing|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18668" PostTypeId="1" AcceptedAnswerId="18677" CreationDate="2019-12-11T05:21:29.437" Score="1" ViewCount="251" Body="&lt;p&gt;The YouTube video &lt;a href=&quot;https://www.youtube.com/watch?v=Iv7n6QEIHIw&quot; rel=&quot;nofollow noreferrer&quot;&gt;Skating Lake Baikal, the world's deepest lake - BBC News&lt;/a&gt; shows a very heavily cracked lake. It doesn't just appear to be a fault line. It appears to be an actual crack that started that goes all the way to the surface. I believe it's natural. I have two questions. My first question is&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;When an ice layer on a frozen lake is cracked the way I described, is it plausible that it happened completely naturally with no human intervention such as having walked on it when it was thin?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My second question is&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If the answer to my first question is yes, then what is one plausible cause of it?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;If the answer to the first question is yes, I really only need the answer of one plausible cause of ice being cracked in that way without human intervention. However, it would be nice if you could give me as many plausible causes from fundamentally different categories as you can find.&lt;/p&gt;&#xA;" OwnerUserId="4846" LastEditorUserId="4846" LastEditDate="2019-12-11T18:58:15.040" LastActivityDate="2019-12-12T12:53:32.163" Title="Why is the ice on a frozen lake sometimes cracked?" Tags="|meteorology|lakes|winter|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18669" PostTypeId="2" ParentId="18668" CreationDate="2019-12-11T09:02:31.600" Score="0" Body="&lt;p&gt;Your question should have been much more concise, it is too rambling and long-winded. With regard to your paragraph on creating a new branch of diving, it also deviates into the world of sport. The marks I saw in your video looked as though they were made by skaters, but you ask whether there is a natural method that a frozen lake could develop a crack without human intervention, so I will give you one, though it probably doesn't explain the marks on Lake Baikal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If a large lake gets frozen over, It may have a small stream or other drainage system which very gradually lowers the water level  beneath the ice. In summer other streams and rainfall replenish it,so the two things balance each other out and the water level usually remains the same. However, what might happen in the winter is that after the Ice has formed, the seepage gradually creates an air gap under the ice. Deprived of support in the middle of the lake, the ice will begin to sag, and if it sags enough, the ice will crack. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-11T09:02:31.600" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18670" PostTypeId="1" CreationDate="2019-12-11T12:57:43.470" Score="5" ViewCount="538" Body="&lt;p&gt;I have been extracting ERA5 data through the Web API. Now I am shifting to CDS API.  In the web API I used the below code to download time series data at a particular lat/lon. In the CDS API, I can't find an equivalent to &quot;ct.geo.extract_point()&quot;. Is there an equivalent? If not, is there a way in which the &lt;strong&gt;area&lt;/strong&gt; keyword can be tweaked to serve the purpose?&lt;/p&gt;&#xA;&#xA;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;import cdstoolbox as ct&#xA;&#xA;@ct.application(title='Data')&#xA;@ct.output.download()&#xA;def retrieve_sample_data():&#xA;    &quot;&quot;&quot;&#xA;    Application main steps:&#xA;&#xA;    - retrieve a variable from CDS Catalogue&#xA;    - produce a link to download it.&#xA;    &quot;&quot;&quot;&#xA;&#xA;    data = ct.catalogue.retrieve(&#xA;        'reanalysis-era5-single-levels',&#xA;        {&#xA;            'variable': 'peak_wave_period', &#xA;            'product_type': 'reanalysis',&#xA;            'year': '1991',&#xA;            'month': [&#xA;                '01', '02', '03', '04', '05', '06',&#xA;                '07', '08', '09', '10', '11', '12'&#xA;            ],&#xA;            'day': [&#xA;                '01', '02', '03', '04', '05', '06',&#xA;                '07', '08', '09', '10', '11', '12',&#xA;                '13', '14', '15', '16', '17', '18',&#xA;                '19', '20', '21', '22', '23', '24',&#xA;                '25', '26', '27', '28', '29', '30',&#xA;                '31'&#xA;            ],&#xA;            'time': ['00:00', '03:00', '06:00', '09:00', '12:00', '15:00', '18:00', '21:00'&#xA;            ],&#xA;        }&#xA;    )&#xA;    data_se = ct.geo.extract_point(data, lon=80.5, lat=12)&#xA;&#xA;    return data_se&#xA;&lt;span class=&quot;math-container&quot;&gt;```&lt;/span&gt;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="18463" LastActivityDate="2019-12-11T12:57:43.470" Title="Extracting point data from ERA5 CDS API" Tags="|meteorology|reanalysis|era|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18671" PostTypeId="2" ParentId="18424" CreationDate="2019-12-11T13:37:07.400" Score="2" Body="&lt;p&gt;I disagree with Michael about the &quot;not as large as the lunar mare&quot; part. &lt;a href=&quot;https://doi.org/10.1016/0016-7037(92)90183-J&quot; rel=&quot;nofollow noreferrer&quot;&gt;Head and Wilson (1992)&lt;/a&gt; mention that the &quot;total area of exposed mare deposits is about 6.3 millions km&lt;sup&gt;2&lt;/sup&gt;&quot; (17 % of the Moon's surface area). They estimated a total volume of 10 millions km&lt;sup&gt;3&lt;/sup&gt;. The largest mare, &lt;a href=&quot;https://en.wikipedia.org/wiki/Oceanus_Procellarum&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oceanus Procellarum&lt;/a&gt;, covers about 4 millions km&lt;sup&gt;2&lt;/sup&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These values are quite comparable with Large Igneous Provinces (LIPs) in terms of area, and are even one order of magnitude lower in terms of volume. From the &lt;a href=&quot;https://doi.org/10.1016/B978-0-12-385938-9.00014-6&quot; rel=&quot;nofollow noreferrer&quot;&gt;Encyclopedia of Volcanoes&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The composite Ontong-Java-Manihiki-Hikurangi plateau covers 3.5&#xA;  million km&lt;sup&gt;2&lt;/sup&gt; with an estimated volume 59-77 million&#xA;  km&lt;sup&gt;3&lt;/sup&gt;. [...] The Kerguelen plateau in the southern Indian&#xA;  Ocean is the second largest LIP, covering 2.3 million km&lt;sup&gt;2&lt;/sup&gt;&#xA;  with a volume of 15 million km&lt;sup&gt;3&lt;/sup&gt; [...] Not all LIPs are&#xA;  oceanic plateaus; for example, the North Atlantic volcanic province,&#xA;  derived from a hot spot presently centered beneath Iceland, has an&#xA;  area of 1.3 million km&lt;sup&gt;2&lt;/sup&gt; [...] Also notable are the Deccan&#xA;  traps in India (1.8 million km&lt;sup&gt;2&lt;/sup&gt;/9.3 million&#xA;  km&lt;sup&gt;3&lt;/sup&gt;).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;If lunar maria seem that large from Earth, it's only because the Moon is small!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But &lt;strong&gt;to know if lunar maria or LIPs would have looked like &quot;glowing lava oceans shinning in the night&quot;, we need to look at emplacement rates rather than just areas and volumes&lt;/strong&gt;. From the same chapter, one can calculate LIP emplacement rates of ~3-13 km&lt;sup&gt;3&lt;/sup&gt; per year. It may seem quite low (for comparison, ocean ridges quietly produce ~20 km&lt;sup&gt;3&lt;/sup&gt; per year), but it is an average output rate over a few million years. As noted on &lt;a href=&quot;http://www.largeigneousprovinces.org/frontiers#melt&quot; rel=&quot;nofollow noreferrer&quot;&gt;largeigneousprovinces.org&lt;/a&gt;, their might be pulses of magmatic activity, with peaks in production rate. This is exactly what's been inferred for lunar maria by &lt;a href=&quot;https://doi.org/10.1016/j.icarus.2015.12.039&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wilson and Head (2017)&lt;/a&gt;: even if the average output rate has been calculated at a very low 0.01 km&lt;sup&gt;3&lt;/sup&gt; per year, they found that some flows could have been emplaced with rates up to 10&lt;sup&gt;6&lt;/sup&gt; m&lt;sup&gt;3&lt;/sup&gt;s&lt;sup&gt;-1&lt;/sup&gt;!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to whether this would have been visible from space: define &quot;from space&quot;! From low Earth orbit like the ISS? From the Moon itself? :)&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2019-12-11T13:37:07.400" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18672" PostTypeId="1" CreationDate="2019-12-11T13:54:21.433" Score="1" ViewCount="58" Body="&lt;p&gt;I would like to ask about origin and inventor of particulate matter pm10, pm2.5.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Who published and defined this formulas and when. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks in advance!&lt;/p&gt;&#xA;" OwnerUserId="18464" LastActivityDate="2019-12-11T13:54:21.433" Title="What's the origin of particulate matter (pm10, pm2 5)" Tags="|climate-change|air-pollution|air-quality|particulates|pm2.5|" AnswerCount="0" CommentCount="2" ClosedDate="2019-12-14T14:30:33.680" ContentLicense="CC BY-SA 4.0" />
  <row Id="18673" PostTypeId="2" ParentId="18657" CreationDate="2019-12-11T15:13:16.687" Score="4" Body="&lt;p&gt;As others have said, a single set of coordinates gives a point rather than an area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I assume that the intent of the question is an understanding of the precision of these coordinates - i.e. what's the area covered by the 1&quot;x1&quot; shape comprising all of the lat and lon values that would round to a whole number of seconds. The answer to that is &quot;it depends&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The distance covered by one arc minute of latitude, by definition, is one nautical mile. One nautical mile is 1852 metres, therefore one arc second (1/60 minutes) of latitude represents just under 31m.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far, so straightfoward. But longitude isn't so simple, because the distance represented by an arc second of longitude is not the same everywhere on the planet - it depends on the latitude. This makes sense if you look at a map and see how the lines of longitude converge - i.e. have less distance between them - towards the poles. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As Barry Carter said in a comment, the distance represented by an arc second of longitude is approximately equal to &lt;span class=&quot;math-container&quot;&gt;$31 \cos(lat)$&lt;/span&gt; metres[1]. Hence, the area of a 1&quot; ~square around any given point is equal to &lt;span class=&quot;math-container&quot;&gt;$31^2 \cos(lat)$&lt;/span&gt; m&lt;sup&gt;2&lt;/sup&gt;. That will vary from zero[2], at the poles, to 961 m&lt;sup&gt;2&lt;/sup&gt; on the equator. At the particular coordinates that you gave as an example, it'd be &lt;span class=&quot;math-container&quot;&gt;$31 \times 31\cos(51.434^{\circ}) \approx 599$&lt;/span&gt; m&lt;sup&gt;2&lt;/sup&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1] Before anybody corrects me, all of the above does assume a spherical earth. In reality It's A Bit More Complicated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[2] Very nearly zero.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-12-11T15:13:16.687" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18675" PostTypeId="1" CreationDate="2019-12-12T08:51:33.377" Score="3" ViewCount="984" Body="&lt;p&gt;My pyferret was working perfectly until I had installed netCDF4 and now it is throwing up this error &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;readline: /etc/inputrc: line 19: term: unknown variable name&#xA;Traceback (most recent call last):&#xA;  File &quot;&amp;lt;string&amp;gt;&quot;, line 1, in &amp;lt;module&amp;gt;&#xA;  File &quot;/home/cccr/msingh/anaconda3/envs/FERRET/lib/python3.7/site- &#xA;   packages/pyferret/__init__.py&quot;, line 45, in &amp;lt;module&amp;gt;&#xA;    from pyferret import libpyferret&#xA;ImportError: libnetcdf.so.13: cannot open shared object file: No such &#xA;file or directory&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="18429" LastActivityDate="2019-12-12T08:52:27.987" Title="How to solve libnetcdf.so.12: cannot open shared object file in pyferret?" Tags="|oceanography|atmosphere-modelling|python|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18676" PostTypeId="2" ParentId="18675" CreationDate="2019-12-12T08:52:27.987" Score="4" Body="&lt;p&gt;You need to uninstall netCDF4 as it is not compatible with pyferret library as of now.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;pip uninstall netCDF4&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;should do.&lt;/p&gt;&#xA;" OwnerUserId="18076" LastActivityDate="2019-12-12T08:52:27.987" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18677" PostTypeId="2" ParentId="18668" CreationDate="2019-12-12T12:53:32.163" Score="1" Body="&lt;p&gt;Ice does crack completely naturally without human intervention. There are many reasons it could do so, one is as mentioned before mechanical stress from in- and outflow that lifts/settles the ice cover.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another one is temperature stress from density changes, because ice changes its density e.g. depending on diurnal temperature changes or simply by cooling as it thickens (or warming as it thaws).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;... and more.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Changing density:&#xA;&lt;a href=&quot;https://www.engineeringtoolbox.com/ice-thermal-properties-d_576.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.engineeringtoolbox.com/ice-thermal-properties-d_576.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastActivityDate="2019-12-12T12:53:32.163" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18678" PostTypeId="2" ParentId="18652" CreationDate="2019-12-12T14:28:44.873" Score="2" Body="&lt;p&gt;In engineering it is common practice to build intensity-duration-frequency (IDF) curves, which basically map out the frequency of a given rainfall event based on its average intensity (mm/hr) and duration of the event. This addresses the issue of needing to classify a 'heavy' rainfall event. In general, the duration and intensity are inversely related (more intense rainfall events tend to last a shorter time).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are many examples of calculation and software packages to actually build these curves, which are used often for engineering design to help decide the storm a given piece of infrastructure is being designed to (e.g. 5 year storm, 25 year storm, etc.). Most municipalities will have developed their own IDF curves to set standards for design. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are also examples of online tools to help generate IDF curves for a given location, such as t&lt;a href=&quot;http://www.eng.uwaterloo.ca/~dprincz/mto_site/map_acquisition.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;his one in Ontario&lt;/a&gt;. This tool is neat as it calculates the IDFs for a given year, and uses trend analysis to predict future changes to the IDF curve, allowing you to also pick the target year for generating the IDF curve.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you see that the intensity/duration changes for a given frequency storm event (e.g. 50 year), that would indicate a shift in the rainfall patterns due to climate change. You may need additional statistical tests to check if these changes are statistically significant (examples of this type of analysis applied &lt;a href=&quot;https://www.tandfonline.com/doi/pdf/10.4296/cwrj3601067&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;https://www.tandfonline.com/doi/pdf/10.4296/cwrj2011-935&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;). You will likely not see much change in these curves over a few years as the datasets overlap quite a bit and the trends will not change rainfall patterns in that short a time frame, however, over a 25 or 50 year period you will likely see some changes in the IDF curves, depending on the location.&lt;/p&gt;&#xA;" OwnerUserId="8440" LastActivityDate="2019-12-12T14:28:44.873" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18679" PostTypeId="1" CreationDate="2019-12-12T16:00:21.340" Score="2" ViewCount="2385" Body="&lt;p&gt;I have been meaning to download the daily mean of ERA 5 reanalysis data from the &lt;a href=&quot;https://cds.climate.copernicus.eu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Copernicus Climate Data Store&lt;/a&gt;, but couldn't find it.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I need the data on pressure levels and currently I am downloading the hourly data on pressure levels, which is very huge, around 2GB for one day.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do they provide the daily means of ERA 5 data?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It doesn't matter even if it's only accessible through the CDS API.&lt;/p&gt;&#xA;" OwnerUserId="9633" LastEditorUserId="5594" LastEditDate="2019-12-13T11:39:17.080" LastActivityDate="2020-04-03T08:57:52.880" Title="Does Climate Data Store provide daily mean of ERA 5 reanalysis data?" Tags="|meteorology|reanalysis|weatherdata|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18680" PostTypeId="2" ParentId="18575" CreationDate="2019-12-12T23:33:46.153" Score="2" Body="&lt;p&gt;The answers so far are broadly correct. Iceland has formed from a coincidence of a constructive plate margin and a mantle plume, or &quot;hot spot&quot;. But to really understand why Iceland is there we need to look at a normal constructive plate boundary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A normal mid-ocean ridge is formed where two plates spread apart so that the mantle, which is at a certain temperature, rises upwards and experiences a decrease in pressure. The lower pressure together with the temperature of the mantle allows some (not all) of the mantle to melt - a process called partial melting. Only a small proportion of the mantle actually melts. This melt rises up through the overlying crust in a series of magma bodies, dykes, and lavas, to form the crust. Crucially, the thickness of the crust that is formed depends on the amount of melt that is created, referred to as the melt thickness.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A normal mid-ocean ridge creates a very thin crust - usually about 7 km. That's just 7 km between the ocean and the mantle. But Iceland is not normal. It sits above a mantle plume, which is a region of anomalously warm mantle. So what happens when we depressurise an area of mantle at a higher temperature than normal? We create a much greater melt thickness. This means the crust that is produced above the plume is greater - as much as 30 km. Since the icelandic crust is so much thicker than normal oceanic crust, the upper part of it is able to rise above the level of the sea. And thus Iceland exists.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To answer your followup questions:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Why do not mid ocean ridges often rise above the sea surface to form islands?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Because it's very rare for a hot spot to coincide with a mid-ocean ridge.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Why are islands more common along convergent plate boundaries where they often form archipelagos?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Because these islands form through very different processes. Convergent plate margins introduce water and other volatiles into the mantle, and these have the effect of reducing the melting temperature of the mantle. This produces melt, which rises up and forms volcanoes and islands. This process occurs at virtually every single destructive plate boundary because the subducting oceanic crust contains water which is liberated during subduction.&lt;/p&gt;&#xA;" OwnerUserId="18470" LastActivityDate="2019-12-12T23:33:46.153" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18681" PostTypeId="1" AcceptedAnswerId="18684" CreationDate="2019-12-13T07:31:59.530" Score="4" ViewCount="252" Body="&lt;p&gt;This is the first time I have ordered satellite imagery via the NOAA CLASS system using the shopping cart, so I am a complete novice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have requested and downloaded old GOES-1 images from May 1979, but the problem is it seems the way in which the files are named perhaps and I don't know how to fix this, as it is affecting the file extension which creates something you subsequently can't open.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, the files I have downloaded (whether over ftp or www option) are called:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;goes01.1979.149.1130.AREA_IR&#xA;goes01.1979.149.1130.AREA_VIS &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;And when you save them, it says you are saving a file with the '.AREA_IR' and '.AREA_VIS' file extension, which is of course not what I want, as how do you open it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, under user preferences, there are only two options for these old images - AREA format or RAW format. So, I choose .raw format which I know I can open. I request another download and I get these two files for downloading:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;goes01.1979.149.1200.a&#xA;goes01.1979.149.1200&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;and, this time it wants to download a '.a' file and a '.1200' file which is obviously not what it's supposed to be.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have tried renaming the files (especially the second set) to no avail -- I have tried .raw on the end, and I saw they use the word dataset so I have even tried .tar and .tar.gz in case it might be an archive -- nothing works.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you go into the details of your order, they do say it is .tar file initially, but I tried to download it by adding the .tar extension upon saving even, and still nothing -- won't open in archive software.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has anyone encountered this? How do I use these files? &lt;/p&gt;&#xA;" OwnerUserId="18471" LastActivityDate="2023-07-06T06:21:38.743" Title="How to open old GOES-1 satellite image files downloaded from NOAA CLASS" Tags="|satellites|software|data-formats|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="18684" PostTypeId="2" ParentId="18681" CreationDate="2019-12-13T13:13:18.697" Score="7" Body="&lt;p&gt;Unfortunately, the older weather satellite data is, the harder it is to read.&#xA;Perhaps &lt;a href=&quot;https://www.ncdc.noaa.gov/wct/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA's Weather and Climate Toolkit&lt;/a&gt; can open it.&lt;/p&gt;&#xA;&lt;p&gt;The old stuff usually comes in tightly packed binary formats that may or may not be well documented (these satellites were designed to take pictures of clouds for weather forecasters to use, us future generations were more or less an afterthought).  Just to illustrate the difficulty: I've previously worked with data from the NOAA HIRS instrument from the late 1970s/early 1980s, and found that the headers contained a mixture of ASCII and EBCDIC information, and that some necessary calibration parameters for the thermistors on the on-board internal warm calibration target were simply lost, and that for some satellites, the available header documentation did not match what was actually in there, and I couldn't read most of the headers.  Other information useful for interpretation existed in the NOAA library, but was unavailable to me due to export restrictions (ITAR).&lt;/p&gt;&#xA;&lt;p&gt;The imager on the first generation GOES satellites is the &lt;a href=&quot;https://www.wmo-sat.info/oscar/instruments/view/610&quot; rel=&quot;nofollow noreferrer&quot;&gt;Visible-Infrared Spin Scan Radiometer (VISSR&lt;/a&gt;, flown on GOES-1–3 between 1975 and 1993.  A &lt;a href=&quot;https://www.wmo-sat.info/oscar/instruments/view/612&quot; rel=&quot;nofollow noreferrer&quot;&gt;similar instrument&lt;/a&gt; with the same name has flown on several Japanese HIMAWARI GMS satellites between 1977 and 2000.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://pytroll.github.io/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pytroll&lt;/a&gt; is a series of Python packages to read and process satellite data.  It includes &lt;a href=&quot;https://satpy.readthedocs.io/en/latest/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Satpy&lt;/a&gt;, which can read a large number of meteorological satellite imager data formats.  Anything that can be read by Satpy can be opened by the &lt;a href=&quot;https://sift.ssec.wisc.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Satellite Information Familiarization Toolkit&lt;/a&gt; (SIFT), developed by the University of Wisconsin-Madison and EUMETSAT.&lt;/p&gt;&#xA;&lt;p&gt;Unfortunately, I don't think Satpy has a reader for GOES-1 VISSR (most focus is on current and future instruments), although it &lt;a href=&quot;https://github.com/pytroll/satpy/issues/486&quot; rel=&quot;nofollow noreferrer&quot;&gt;can read VISSR on GMS-5 and GOES-9&lt;/a&gt; since Satpy 0.43 (released July 2023).  Considering the similarity of the instruments, a reader for GOES-1 VISSR should hopefully be similar to the one for GMS VISSR.  For GOES VISSR, &lt;a href=&quot;http://artefacts.ceda.ac.uk/badc_datadocs/gedex/detail/vissr.det&quot; rel=&quot;nofollow noreferrer&quot;&gt;some information appears retained at CEDA&lt;/a&gt;, but unfortunately that appears to be lacking in the detail you would need.&lt;/p&gt;&#xA;&lt;p&gt;If you plan to develop a reading routine (you'd need to learn Python first if you don't know it already), do hop in to the &lt;a href=&quot;https://pytroll.slack.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pytroll slack&lt;/a&gt; for advice.  There are also Pytroll workshops (normally twice a year) that are a great resource if you intend to work on a new satellite reader.&lt;/p&gt;&#xA;&lt;p&gt;There might exist propriety software that can read this data, but unless you work at an employer that holds a license for such, that is going to be difficult to access.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2023-07-06T06:21:38.743" LastActivityDate="2023-07-06T06:21:38.743" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18685" PostTypeId="2" ParentId="18679" CreationDate="2019-12-13T13:37:51.070" Score="3" Body="&lt;h1&gt;tl;dr&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;I would suggest using the &lt;a href=&quot;https://cds.climate.copernicus.eu/toolbox-editor&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Toolbox&lt;/strong&gt; of the Copernicus CDS&lt;/a&gt;. Via the Toolbox, you can choose datasets, process them and download the processed results. You have to be registered and logged-in to use the Toolbox.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;How to find out how to select the dataset of interest&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Use the search of the CDS and go to the bottom of the page. There, you can click/tab &lt;em&gt;Show Toolbox request&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8jFr3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8jFr3.png&quot; alt=&quot;&amp;quot;Show Toolbox request&amp;quot; button in the CDS search&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The page is extended and you get some code.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IIyJ7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IIyJ7.png&quot; alt=&quot;Code for the toolbox to access the selected dataset&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Access the Copernicus CDS Toolbox&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Now go to the top of the page and click/tab &lt;em&gt;Toolbox&lt;/em&gt; or go to this URL: &lt;a href=&quot;https://cds.climate.copernicus.eu/toolbox-editor&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://cds.climate.copernicus.eu/toolbox-editor&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/shD5k.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/shD5k.png&quot; alt=&quot;Copernicus CDS Toolbox&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You have to be registered to the Copernicus CDS service and be logged-in to be able to use the Toolbox. On the left, you have some example scripts. You can select datasets, process them, create figures, download data and much more. Amongst others, &lt;a href=&quot;https://code.mpimet.mpg.de/projects/cdo/&quot; rel=&quot;nofollow noreferrer&quot;&gt;cdo (Climate Data Operators)&lt;/a&gt; can be used to process the data. The programming has to be done in Python. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can select a dataset, calculate daily means and download the processed data via the Toolbox. Combining the cdo example (slightly modified) with the code from the search (described above) should yield some useful code for you.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Example code for the Copernicus CDS Toolbox&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Here is an example request, which obtains a part of the data you want. It obtains only data for the year 2007 and for three pressure levels.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;import cdstoolbox as ct&#xA;&#xA;&#xA;@ct.application(title='Retrieve Data')&#xA;@ct.output.download()&#xA;def retrieve_sample_data():&#xA;    data = ct.catalogue.retrieve(&#xA;        'reanalysis-era5-pressure-levels',&#xA;        {&#xA;            'product_type': 'reanalysis',&#xA;            'pressure_level': [&#xA;                '1', '2', '3',&#xA;            ],&#xA;            'year': '2007',&#xA;            'month': [&#xA;                '01', '02', '03',&#xA;                '04', '05', '06',&#xA;                '07', '08', '09',&#xA;                '10', '11', '12',&#xA;            ],&#xA;            'day': [&#xA;                '01', '02', '03',&#xA;                '04', '05', '06',&#xA;                '07', '08', '09',&#xA;                '10', '11', '12',&#xA;                '13', '14', '15',&#xA;                '16', '17', '18',&#xA;                '19', '20', '21',&#xA;                '22', '23', '24',&#xA;                '25', '26', '27',&#xA;                '28', '29', '30',&#xA;                '31',&#xA;            ],&#xA;            'time': [&#xA;                '00:00', '01:00', '02:00',&#xA;                '03:00', '04:00', '05:00',&#xA;                '06:00', '07:00', '08:00',&#xA;                '09:00', '10:00', '11:00',&#xA;                '12:00', '13:00', '14:00',&#xA;                '15:00', '16:00', '17:00',&#xA;                '18:00', '19:00', '20:00',&#xA;                '21:00', '22:00', '23:00',&#xA;            ],&#xA;        }&#xA;    )&#xA;&#xA;    data_daily = ct.climate.daily_mean(data)&#xA;&#xA;    return data_daily&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2019-12-13T13:37:51.070" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18687" PostTypeId="1" CreationDate="2019-12-13T17:44:30.420" Score="1" ViewCount="96" Body="&lt;p&gt;My son recently found this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8IvIz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8IvIz.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;while walking at &lt;a href=&quot;https://en.wikipedia.org/wiki/Waterloo_Bay&quot; rel=&quot;nofollow noreferrer&quot;&gt;Waterloo Bay&lt;/a&gt; in Northern Ireland. It looks (to my untrained eye) like it could be a plant fossil. Is this correct? If so, is it possible to tell anything more about it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It was found at the boundary of the Triassic and Jurassic layers, but had been broken free so might have come from elsewhere. The rock type matches the Jurassic layers. The included photograph covers a height of 15-20cm.&lt;/p&gt;&#xA;" OwnerUserId="18475" LastActivityDate="2019-12-14T19:28:50.633" Title="What is this (possible) fossil from the triassic/jurassic boundary?" Tags="|fossils|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18688" PostTypeId="2" ParentId="14854" CreationDate="2019-12-13T22:39:43.603" Score="1" Body="&lt;p&gt;In southern Canada where there is plenty of sedimentary rock, Isostatic uplift is normal as the many ice ages in the quaternary epoch have created a situation where they have pushed down sediments which want to lift back up if given a chance and with the St. Lawrence River being a fault for instance, they gain that opportunity with releasing off some of that pressure and subsequent earthquakes ensue. Southern Ontario is very close to the middle of the North American Plate.&lt;/p&gt;&#xA;" OwnerUserId="18476" LastActivityDate="2019-12-13T22:39:43.603" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18689" PostTypeId="2" ParentId="18687" CreationDate="2019-12-13T22:59:52.427" Score="0" Body="&lt;p&gt;Your fossil is almost certainly closely related to some fossil plants from West Malaysia depicted on the website of The Fossil Forum, and also assigned to the Triassic - Jurassic boundary. The Malaysian fossils, however, are in a better state of preservation than yours. It may be that S.E. Asia and Europe were closer together in those days, but I couldn't swear to it.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-13T22:59:52.427" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18690" PostTypeId="2" ParentId="18687" CreationDate="2019-12-13T23:10:13.797" Score="1" Body="&lt;p&gt;Its definitely a flowering plant which evolved in the early Mesozoic Era. Also, Pangaea was beginning to break up, but not fully broken up so climate would be than likely be Continental-Maritime allowing for dry weather and water cycle contributions from the surrounding body of water as it broke apart. Also, this land was positioned a little closer to the equator at that time and if found in Ireland, it would have been 'attached' to northwest Africa and the east coast of North America to the west making it possible from a climate and geographical situation. Have a look at this video of Continental Drift movements of parts of the world at 200 million yrs ago in the roughly similar time period you suggest: view at 3:47 for 200 mya and 4:03 to view the recognizable formation of the British Isles. Enjoy! &lt;a href=&quot;https://www.youtube.com/watch?v=UwWWuttntio&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=UwWWuttntio&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="18476" LastActivityDate="2019-12-13T23:10:13.797" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18691" PostTypeId="2" ParentId="10626" CreationDate="2019-12-13T23:31:59.123" Score="0" Body="&lt;p&gt;My first thought would be the fact that deserts are associated with descending air from the upper Troposphere so therefore, the formation of Pangaea would produce a situation of low or no cloud cover as there would be little inland waterways and therefore, energy would escape out to space in the evening and be replaced by descending cooler and denser air that would heat up in the desert environment from friction and a rising sun toward its zenith. I question if the early earth could be considered a desert only from the point of view that air would be rising more at this time due to the intense heat from a hot earth and one that was still growing from bombardments.&lt;/p&gt;&#xA;" OwnerUserId="18476" LastActivityDate="2019-12-13T23:31:59.123" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18695" PostTypeId="1" CreationDate="2019-12-14T15:18:12.567" Score="1" ViewCount="46" Body="&lt;p&gt;If there is snow on the ground in the fall season, at a location 50 km away north of a warmer body of water to the south  and that location is receiving fog, what is causing the fog that is occurring in the morning despite very little wind and not from a southerly direction.&lt;/p&gt;&#xA;" OwnerUserId="18476" LastEditorUserId="18476" LastEditDate="2019-12-14T16:06:33.517" LastActivityDate="2019-12-14T16:06:33.517" Title="Advection Fog or____________" Tags="|meteorology|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="18697" PostTypeId="1" CreationDate="2019-12-14T16:21:08.997" Score="1" ViewCount="39" Body="&lt;p&gt;Why do some coals show cleating and some not? Is cleating in coal related to coal's plant source or depositional process or post depositional processes? &lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="2470" LastEditDate="2019-12-14T17:21:21.033" LastActivityDate="2019-12-14T17:21:21.033" Title="What is the origin of cleating in coal?" Tags="|coal|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18698" PostTypeId="2" ParentId="18697" CreationDate="2019-12-14T16:52:26.930" Score="1" Body="&lt;p&gt;Short answer, its not well studied. It is most likely a diagenic process just because that is the source of most fractures in rock. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0166516297000128&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/abs/pii/S0166516297000128&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S1674775514000341&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/S1674775514000341&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2019-12-14T16:52:26.930" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18699" PostTypeId="1" CreationDate="2019-12-14T18:00:11.273" Score="9" ViewCount="562" Body="&lt;p&gt;Iceland has a much more temperate &lt;a href=&quot;https://en.wikipedia.org/wiki/Iceland#Climate&quot; rel=&quot;noreferrer&quot;&gt;climate&lt;/a&gt; than its latitude (~65 degrees) would suggest, thanks to the North Atlantic Current bringing relatively warm water/air so far up north.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a lot of &lt;a href=&quot;https://en.wikipedia.org/wiki/Iceland#Geology&quot; rel=&quot;noreferrer&quot;&gt;geothermal activity&lt;/a&gt; (geysers, volcanoes) in Iceland, because it lies on the boundary between the Eurasian plate and the North American one. They generate a lot of heat, at least locally. I'm curious and haven't made any calculations (I wouldn't even know where to begin) but does this activity influence the climate in Iceland in a meaningful way? E.g. without the geothermal activity, would the mean annual temperature drop, and if so, by how many degrees?&lt;/p&gt;&#xA;" OwnerUserId="2958" LastActivityDate="2019-12-14T19:04:26.023" Title="Does the geothermal activity influence the climate in Iceland?" Tags="|climate|geothermal-heat|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18700" PostTypeId="2" ParentId="18699" CreationDate="2019-12-14T18:35:08.473" Score="5" Body="&lt;p&gt;Since micro climates of a location are mostly based on temperature and precipitation patterns, I would suggest that yes, if focusing on precipitation alone, one would expect rising heat from geothermal activity off the surface as a variable to affect the formation and release of precipitation. But one would have to check what part of the island geothermal activity was highest as the jetstream would drag weather west to east if nearby, and given that it is a small island, may not record such an occurrence as a significant effect from the rising heat available around Iceland. I did find this article which is somewhat supportable of a heat increase around Iceland due to geothermal activity &gt; Douglass/Patel and Knox, 2005. GEOPHYSICAL RESEARCH LETTERS, VOL. 32 &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2004GL021816&quot; rel=&quot;noreferrer&quot;&gt;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2004GL021816&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="18476" LastActivityDate="2019-12-14T18:35:08.473" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18702" PostTypeId="2" ParentId="18699" CreationDate="2019-12-14T19:04:26.023" Score="4" Body="&lt;p&gt;You have already hit on the reason Iceland has such a mild climate: the Gulf Stream. Geothermal heat does not measurably affect the Icelandic climate unless you make your measurements very close indeed to geothermal activity. A lot depends on whereabouts you are in Iceland. The interior is mountainous and therefore colder, while the northern coast is nearer the Arctic Circle. It has been decided that Reykjavik, on the south-west coast, is the best place to make climate measurements rather than on a mountain glacier or on top of a geothermal heat source. Major volcanic eruptions are few and far between.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-14T19:04:26.023" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18703" PostTypeId="2" ParentId="18687" CreationDate="2019-12-14T19:28:50.633" Score="1" Body="&lt;p&gt;Your best bet is to take this to a local natural history museum they are usually more than happy to identify things, and they will be familiar with the local fossils. They may also be interested in exploring the location it came from. Just based on the image it might be a fossil or it might not, the waterloo bay area is not know for producing plant fossils but marine fossils so a marine animal is more likely, it could also just be chemical stain which are not uncommon in mudstones and shales. just from the image it is impossibly to say for certain. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2019-12-14T19:28:50.633" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18706" PostTypeId="1" AcceptedAnswerId="18707" CreationDate="2019-12-15T10:19:40.163" Score="3" ViewCount="212" Body="&lt;p&gt;I discovered &lt;a href=&quot;ftp://data.iac.ethz.ch/CMIP6/input4MIPs/UoM/GHGConc/CMIP/yr/atmos/UoM-CMIP-1-1-0/GHGConc/gr3-GMNHSH/v20160701/mole_fraction_of_carbon_dioxide_in_air_input4MIPs_GHGConcentrations_CMIP_UoM-CMIP-1-1-0_gr3-GMNHSH_0000-2014.csv&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; a set of yearly historical atmospherical CO2-concentrations from year 0 - 2014. Since they haven't mentioned which measure they used, I'm not sure whether it is right to talk about ppm by volume. The name of the file contains the following &quot;mole_fraction_of_carbon_dioxide_in_air_input4MIPs&quot; which leads me to think of ppm by mole. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do you think  I'm right? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This leading to: is it plausible to have that downward tendency about 1600 and if why?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you in advance for your help.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I plotted the data with Excel:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YPtXk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YPtXk.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18482" LastEditorUserId="1411" LastEditDate="2019-12-18T12:23:00.877" LastActivityDate="2019-12-18T15:14:58.087" Title="Reference units for CO2 concentration in the atmosphere and meaning of a slight downward tendancy during the 1600" Tags="|atmosphere|climate-change|co2|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18707" PostTypeId="2" ParentId="18706" CreationDate="2019-12-15T14:15:45.250" Score="4" Body="&lt;p&gt;The file you provided do not have metadata nor context, which make it pretty much useless as it is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But, by reading the title and as you suggested, we can assume that the unit used in the sheet is mole fraction of &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; in air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also the value of the data is fitting the range of the &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; historic measurements on Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By definition, a mole fraction is the ratio of mole of a given component (solute) over the total mole count in a target solution. In our case, this mean:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$mole\:fraction\:of\:CO_2= \frac{measured\:CO_2}{total\:mole\:in\:the\:sample\:solution}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is well expressed and explained &lt;a href=&quot;https://www.lenntech.com/calculators/ppm/converter-parts-per-million.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; in the section titled: &lt;strong&gt;Parts per Million by Volume (or mole) in Air&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In air pollution literature ppm applied to a gas, &lt;strong&gt;always means parts per million by volume or by mole&lt;/strong&gt;. These are identical for an ideal gas, and practically identical for most gases of air pollution interest at 1 atm. Another way of expressing this value is ppmv. One part per million (by volume) is equal to a volume of a given gas mixed in a million volumes of air:&#xA;  &lt;span class=&quot;math-container&quot;&gt;$1\:ppm = \frac{1\:gas\:volume}{1\:million\:air\:volume}$&lt;/span&gt; at 1 atmosphere pressure.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Thus a simple conversion can be applied and the equation solved, knowing the weight of a mole of &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; and the typical weight of air. To answer your question, mole and volume are interchangeable in this context.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This would be my honest take, considering the limited available information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;About the downward tendency during the 1600: This was around the time when the Little Ice Age began; There was the Maunder minimum (first low) due to a solar spot low and then a small peak and then the Dalton minimum (second low) before the present peak. Here is &lt;a href=&quot;https://www.britannica.com/science/Dalton-minimum&quot; rel=&quot;nofollow noreferrer&quot;&gt;an example&lt;/a&gt; of how low the sunspot activity was at that time (especially Maunder) from Britannica.com&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/c78I7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/c78I7.jpg&quot; alt=&quot;Sunspots&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consequences of those two events, detectable already during Maunder was a trend of global cooling and a diminution of the atmospheric &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt;.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastEditorUserId="1411" LastEditDate="2019-12-18T15:14:58.087" LastActivityDate="2019-12-18T15:14:58.087" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18708" PostTypeId="2" ParentId="18092" CreationDate="2019-12-15T15:10:40.980" Score="1" Body="&lt;p&gt;Fossil preservation in  lacustrine marls is fairly common so it is really not that indicative of anything. Species might be used for wider correlation, but that's about it. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2019-12-15T15:10:40.980" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18709" PostTypeId="1" CreationDate="2019-12-15T18:54:25.860" Score="4" ViewCount="71" Body="&lt;p&gt;Let &lt;span class=&quot;math-container&quot;&gt;$L_{obu}$&lt;/span&gt; denote the Obukhov length, &lt;span class=&quot;math-container&quot;&gt;$z$&lt;/span&gt; denote the height of measurement and &lt;span class=&quot;math-container&quot;&gt;$h_c$&lt;/span&gt; denote the canopy(obstacle) height.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have seen two definitions of the stability parameter: &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\zeta = z/L_{obu}$&lt;/span&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;define zero-displacement height &lt;span class=&quot;math-container&quot;&gt;$z_d = \frac{2}{3}h_c$&lt;/span&gt;. Then&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\zeta = (z-z_d)/L_{obu}$&lt;/span&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Questions&lt;/strong&gt;: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A. Which definition is correct? Can you provide some reference where this is discussed?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;B. What are the typical values for &lt;span class=&quot;math-container&quot;&gt;$\zeta$&lt;/span&gt;?&lt;/p&gt;&#xA;" OwnerUserId="18483" LastEditorUserId="18483" LastEditDate="2019-12-15T18:59:36.320" LastActivityDate="2022-12-27T21:01:57.373" Title="Stability Parameter $\zeta$ definition" Tags="|meteorology|turbulence|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18710" PostTypeId="2" ParentId="18092" CreationDate="2019-12-15T19:58:13.800" Score="2" Body="&lt;p&gt;Shell stable isotopes, for oxygen and carbon reveals, if the gastropoda had lived in brackish, lacustrine or palustrine environment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For discussion please see paper below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Latal, C., Piller, W. E., &amp;amp; Harzhauser, M. (2004). Palaeoenvironmental reconstructions by stable isotopes of Middle Miocene gastropods of the Central Paratethys. Palaeogeography, Palaeoclimatology, Palaeoecology, 211(1-2), 157-169.&lt;/p&gt;&#xA;" OwnerUserId="15195" LastActivityDate="2019-12-15T19:58:13.800" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18711" PostTypeId="2" ParentId="18650" CreationDate="2019-12-15T22:09:16.827" Score="-2" Body="&lt;p&gt;Perhaps, a coincidence of a lack of cosmic rays stimulating lightning in that moment could be the variable here that is lacking to kickstart lightning in those two situations mentioned by the question/problem. A Russian physcist named Gurevich proposed that after many years of failed measurements to explain the spark inside a cloud. Gurevich suggested that even cosmic rays coming from halfway across the galaxy could be enough to provide 'a conductive path that initiates lightning'. &lt;a href=&quot;https://www.scientificamerican.com/article/experts-do-cosmic-rays-cause-lightning/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.scientificamerican.com/article/experts-do-cosmic-rays-cause-lightning/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18476" LastEditorUserId="18476" LastEditDate="2019-12-15T23:39:42.707" LastActivityDate="2019-12-15T23:39:42.707" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18712" PostTypeId="1" AcceptedAnswerId="18714" CreationDate="2019-12-16T00:07:38.530" Score="14" ViewCount="5964" Body="&lt;p&gt;Suppose that a super-powerful earthquake occurred anywhere on Earth, say one with the value 10 on Richter's scale. The quake can have any value but as can be read in a comment below the highest value ever measured was 32 on a superdense star. In that case, it's much more difficult to tear the star apart. The Earth,  in contrast, &lt;strong&gt;could be&lt;/strong&gt; torn apart by a quake with value 10 because she is highly less massive.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Suppose the quake was mainly transversal (in a vertical direction). Could it be that correspondingly waves emerged from the center of the quake, traveling the Earth around to come together and reinforced again on the opposite side of the center, with the effect that the quake was felt more strongly on the opposite side of the center than at places halfway from the center (or halfway to the opposite side of the center), to say it in one long breath? Or would too much energy be absorbed from the waves by the Earth to reach the opposite side? &lt;/p&gt;&#xA;" OwnerUserId="5945" LastEditorUserId="5945" LastEditDate="2019-12-16T23:52:58.947" LastActivityDate="2019-12-16T23:52:58.947" Title="If a very huge Earthquake occured anywhere on Earth could waves emerge to come together again on the opposite side?" Tags="|earthquakes|waves|scale|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18713" PostTypeId="1" CreationDate="2019-12-16T02:25:26.097" Score="5" ViewCount="68" Body="&lt;p&gt;I understand how to find an epicenter using three sensor locations and why three locations are needed.  Is it possible, though very improbable, to find an epicenter if you only have two seismic stations that are positioned in a way where the possible epicenter locations when drawn out in a circle only meet in one place?&lt;/p&gt;&#xA;" OwnerUserId="18486" LastEditorUserId="2470" LastEditDate="2019-12-16T06:26:44.890" LastActivityDate="2019-12-16T06:26:44.890" Title="Locating an seismic epicenter" Tags="|earthquakes|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18714" PostTypeId="2" ParentId="18712" CreationDate="2019-12-16T03:40:21.220" Score="26" Body="&lt;p&gt;It is called &quot;antipodal focusing&quot;. See for example &lt;a href=&quot;https://www.researchgate.net/publication/268992173_Antipodal_focusing_of_seismic_waves_observed_with_the_USArray&quot; rel=&quot;noreferrer&quot;&gt;Antipodal focusing of seismic waves observed with the USArray&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We present an analysis of the M-w = 5.3 earthquake that occurred in the Southeast Indian Ridge on 2010 February 11 using USArray data. The epicentre of this event is antipodal to the USArray, providing us with an opportunity to observe in details the antipodal focusing of seismic waves in space and time. We compare the observed signals with synthetic seismograms computed for a spherically symmetric earth model&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The above paper deals with &quot;body waves&quot; that travel through the interior of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are also Rayleigh waves that travel on the surface and can &lt;a href=&quot;https://en.wikipedia.org/wiki/Rayleigh_wave#Rayleigh_waves_from_earthquakes&quot; rel=&quot;noreferrer&quot;&gt;travel around the Earth several times before dissipating&lt;/a&gt; (Wikipedia). &lt;a href=&quot;https://academic.oup.com/gji/article/187/1/529/564818&quot; rel=&quot;noreferrer&quot;&gt;Antipodal focusing of seismic waves due to large meteorite impacts on Earth&lt;/a&gt; does numerical simulations of surface waves at the antipode of the Chicxulub impact. The waves do not arrive at the antipode at the same time because of Earth’s ellipsoidal shape and different rock properties along their paths.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Myz77.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Myz77.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;  Isosurfaces of the norm of the peak displacement vector after a vertical impact for the impact hemisphere (left-hand side) and antipodal hemisphere (right-hand side).  &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(They say: &quot;Note that contours of the continents are today’s, not their end Cretaceous positions, and therefore do not show the original Chicxulub antipode 65 Ma.&quot;)&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2019-12-16T23:15:55.057" LastActivityDate="2019-12-16T23:15:55.057" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="18715" PostTypeId="2" ParentId="17017" CreationDate="2019-12-16T13:46:55.067" Score="5" Body="&lt;p&gt;I just came upon &lt;a href=&quot;https://doi.org/10.1007/BF01145887&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper by Tomascik et al. (1996)&lt;/a&gt;. It does not answer directly your question, but I found it sufficiently relevant to post it here anyway. It is a study of coral colonization after emplacement of a lava flow. They found that only five years after emplacement of an andesitic lava flow from Gunung Api in 1988, large parts of this new coastline was already covered by coral. They mention a previous study (Grigg and Maragos 1974) on Hawaii where it took 20&lt;span class=&quot;math-container&quot;&gt;$-$&lt;/span&gt;50 years for coral to colonize a submerged lava flow.&lt;/p&gt;&#xA;&lt;p&gt;Of course, in those cases the coral could come from nearby reefs, while in the case of a new island it has to come from further away. So those fast colonization timescales are not directly applicable to your question.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2021-09-08T10:30:43.447" LastActivityDate="2021-09-08T10:30:43.447" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18716" PostTypeId="1" CreationDate="2019-12-16T14:31:46.123" Score="1" ViewCount="125" Body="&lt;p&gt;Why do clouds form a 'tablecloth' which exactly fits the top of Table Mountain near Capetown, South Africa? Something about the table top tailors the clouds to fit it exactly. The thickness is smooth and even, at a rough guess about ten metres thick.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-09-11T23:42:43.263" Title="Cloud Formations Near Capetown" Tags="|meteorology|clouds|mountains|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18717" PostTypeId="2" ParentId="18716" CreationDate="2019-12-16T14:56:55.933" Score="2" Body="&lt;p&gt;This is adiabatic compression of descending air. The air warms and clouds dissolve. The air is blown by a wind that's roughly perpendicular to the ridge, causing it to rise, cool and eventually condense on the windward side and sink and warm on the leeward.&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user18411" LastEditDate="2019-12-16T15:22:26.167" LastActivityDate="2019-12-16T15:22:26.167" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18718" PostTypeId="1" CreationDate="2019-12-16T15:00:25.057" Score="3" ViewCount="131" Body="&lt;p&gt;I need to understand some basics about atmospheric modelling, since I am working with data from the COSMO model for my thesis. My questions mainly concern model validation, like learning about the most common metrics to evaluate model accuracy. Therefore, does anybody have suggestions concerning good introductory textbooks for atmospheric modelling? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To clarify where I am coming from:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am looking at regional climate data for the Antarctic as simulated by COSMO in Climate Mode driven by ERA-Interim. Observations in the region and for the period of interest are naturally sparse, so I wondered how I can validate the model data against the few observations there are. This led me to the question whether there are some general practices and statistical methods to validate output of an atmospheric model and hence the idea to ask for pointers to introductory textbooks.&lt;/p&gt;&#xA;" OwnerUserId="18370" LastEditorUserId="6129" LastEditDate="2020-05-06T09:11:49.013" LastActivityDate="2020-05-06T09:11:49.013" Title="Literature on atmospheric modelling" Tags="|meteorology|atmosphere-modelling|reference-request|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18719" PostTypeId="2" ParentId="17017" CreationDate="2019-12-16T19:47:11.460" Score="3" Body="&lt;p&gt;based on Hunga Tonga, either within a decade or even before the volcano ever reaches the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://link.springer.com/article/10.1007/s00338-019-01868-8&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://link.springer.com/article/10.1007/s00338-019-01868-8&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://matangitonga.to/2019/12/09/Tonga-corals-hunga-volcano&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://matangitonga.to/2019/12/09/Tonga-corals-hunga-volcano&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2019-12-16T20:12:00.470" LastActivityDate="2019-12-16T20:12:00.470" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18720" PostTypeId="1" CreationDate="2019-12-16T21:20:57.577" Score="3" ViewCount="69" Body="&lt;p&gt;Would the pansharpening of Spot 6 work on the NIR band? Since the wavelengths captured by the panchromatic band does not overlap with the NIR band. The band designations are in the attached image.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Xji1d.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Xji1d.png&quot; alt=&quot;Wavelength of Spot 6 spectral bands&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14152" LastEditorUserId="18081" LastEditDate="2019-12-19T18:58:48.210" LastActivityDate="2019-12-19T18:58:48.210" Title="Pansharpening of Spot 6 image" Tags="|remote-sensing|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18721" PostTypeId="1" CreationDate="2019-12-16T21:41:05.060" Score="3" ViewCount="390" Body="&lt;p&gt;It seems to be the case that 1C of global heating caused the whole global temperature bell curve to shift two standard deviations to the right. (see below)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To anyone knowing much about statistics and bell curves this would seem to make the 80 years BAU 5C temperature anomaly have the drastically lethal consequence of much more frequent heat waves greatly exceeding the 44C maximum human survival limit. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My own projections of the current trend are a little more pessimistic than IPCC RCP8.5 projections. They simply extrapolate the current exponential increase of atmospheric CO2 and project 877 PPM by 2100 then apply the current IPCC equilibrium CO2 sensitivity formula&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;3C ± 1.5C for every doubling of atmospheric CO2&lt;/strong&gt;&lt;br&gt;&#xA;log2(877/280) * 1.5 = 2.47&lt;br&gt;&#xA;log2(877/280) * 3.0 = 4.94   // Business as usual for 80 more years&lt;br&gt;&#xA;log2(877/280) * 4.5 = 7.41&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;​​​​&lt;a href=&quot;https://www.giss.nasa.gov/research/briefs/hansen_17/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.giss.nasa.gov/research/briefs/hansen_17/&lt;/a&gt; &lt;br&gt;&#xA;When we examine this graph we see that a single degree of temperature anomaly is associated with a shift of the whole temperature bell curve two standard deviations to the right. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zJI26.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zJI26.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we hypothesize that a single degree of temperature anomaly directly caused the entire bell curve to shift the right two standard deviations then the consequences of a 5C would seem to be quite lethal. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Once we numerically quantify the relationship between temperature anomaly and shifts of the bell curve then we would be able to apply this to historical geographical  temperature extremes and predict the frequency, geographic and temporal extent of heat waves that would kill everything within their boundaries. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This relationship seems to predict that the 5C temperature anomaly projected from &quot;business as usual&quot; for 80 more years could reasonably result in 60C (140F) killer heat waves. A 60C heat wave will kill everything in its path very quickly. Apparently humans cannot survive 44C for very long.&lt;/p&gt;&#xA;" OwnerUserId="17970" LastEditorUserId="595" LastEditDate="2019-12-25T19:48:09.037" LastActivityDate="2019-12-25T19:48:09.037" Title="Are 60C heat waves predicted by 5C of global heating? (The worst consequence of global heating)" Tags="|climate-change|" AnswerCount="1" CommentCount="6" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18722" PostTypeId="1" CreationDate="2019-12-16T23:14:51.333" Score="5" ViewCount="106" Body="&lt;p&gt;Why has it been so warm in Moscow, Russia the past few winters where the temperatures even overnight have been above freezing when normally it gets brutally cold?&lt;/p&gt;&#xA;" OwnerUserId="17923" LastActivityDate="2019-12-16T23:14:51.333" Title="Climate Change in the North" Tags="|climate-change|climate|temperature|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18723" PostTypeId="2" ParentId="13644" CreationDate="2019-12-17T08:52:06.723" Score="3" Body="&lt;p&gt;I can't answer the question in detail but maybe take some of the tension, addressing the so called &lt;a href=&quot;https://www.semanticscholar.org/paper/Late-Pleistocene-human-population-bottlenecks%2C-and-Ambrose/b783b6fe453a9879fc3193d22efdde5d7629337e&quot; rel=&quot;nofollow noreferrer&quot;&gt;bottleneck hypothesis&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It was never really supported by archaeology, the mentioned article just adds to the evidence that human variety didn't suffer that greatly from the Toba eruption as the bottleneck hypothesis might suggest and that there was no decade long volcanic winter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Example from lake Malawi after the eruption:&#xA;&lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0047248417302750?via%3Dihub&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/abs/pii/S0047248417302750?via%3Dihub&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Southe Africa:&#xA;&lt;a href=&quot;https://www.nature.com/articles/nature25967&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/nature25967&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;India:&#xA;&lt;a href=&quot;https://science.sciencemag.org/content/317/5834/114&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://science.sciencemag.org/content/317/5834/114&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And to my knowledge no extinction signal in &lt;a href=&quot;https://www.nature.com/articles/s41598-019-54305-9&quot; rel=&quot;nofollow noreferrer&quot;&gt;Neandertal population&lt;/a&gt; (they were few anyway) during oxygen isotope stage 4 in Europe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some think that it is time to put the bottleneck hypothesis ad acta. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is evidence that eruptions &quot;fuel&quot; phytoplankton, but not necessarily connected to volcanic winters.&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user18411" LastEditDate="2019-12-17T11:58:13.150" LastActivityDate="2019-12-17T11:58:13.150" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18724" PostTypeId="1" CreationDate="2019-12-17T14:59:43.750" Score="1" ViewCount="1258" Body="&lt;p&gt;I am trying to calculate wind speed from the U and V wind components of a &lt;code&gt;Weather Research and Forecasting&lt;/code&gt; (WRF) simulation. However, I came to realize that some variables of the model (including wind components) are staggered. This makes it really difficult to analyze the model output as is, since the dimensions of staggered variables differ from those of non-staggered variables .&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anybody have any hints on how to de-stagger these fields in a netcdf file produced by the WRF model?&lt;/p&gt;&#xA;" OwnerUserId="2940" LastActivityDate="2019-12-18T15:41:11.323" Title="How to de-stagger (or unstagger) WRF wind fields?" Tags="|meteorology|models|numerical-modelling|wrf|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18725" PostTypeId="2" ParentId="18724" CreationDate="2019-12-17T17:24:23.980" Score="1" Body="&lt;p&gt;The simplest way I've found in Python is to use the &lt;a href=&quot;https://wrf-python.readthedocs.io/en/latest/user_api/generated/wrf.getvar.html#wrf.getvar&quot; rel=&quot;nofollow noreferrer&quot;&gt;getvar&lt;/a&gt; function with the 'ua,' 'va,' or 'wa' variables from the &lt;a href=&quot;https://wrf-python.readthedocs.io/en/latest/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;WRF-Python module&lt;/a&gt;. Alternatively, you can take the midpoint between the staggers.&lt;/p&gt;&#xA;&lt;p&gt;Edit: For example, using the WRF-Python module, you can get the destaggered wind variables with the following code&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;code&gt;import netcdf4 as nc&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;import wrf&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;f=nc.Dataset('example.nc')&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;u=wrf.getvar(f,'ua')&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;v=wrf.getvar(f,'va')&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;w=wrf.getvar(f,'wa')&lt;/code&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="704" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-12-18T15:41:11.323" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18726" PostTypeId="2" ParentId="16527" CreationDate="2019-12-17T19:02:07.923" Score="1" Body="&lt;p&gt;I've come to a solution. I have followed &lt;a href=&quot;https://earthscience.stackexchange.com/users/1066/gansub&quot;&gt;@gansub&lt;/a&gt;'s suggestion to check what there is already there, before reinventing the wheel. I found MetPy's code very (too) well structured, so the code for advection was sparse among several different functions; not so immediate to trace back and put a function together. However, GrADS brings a very nice example on how to easily build such a function in their documentation page for the &lt;code&gt;cdiff&lt;/code&gt; function &lt;a href=&quot;http://cola.gmu.edu/grads/gadoc/gradfunccdiff.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. So I rewrote their code in Python, and it now works well. I wrote a small package available &lt;a href=&quot;https://github.com/davidmnielsen/mygrads&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, if anyone is interested in the working solution. &lt;/p&gt;&#xA;" OwnerUserId="8396" LastActivityDate="2019-12-17T19:02:07.923" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18727" PostTypeId="1" CreationDate="2019-12-18T00:21:44.067" Score="1" ViewCount="58" Body="&lt;p&gt;I have a doubts about how &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; absorbs an re-emits infra red (IR) radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's imagine an only-&lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; atmosphere. In this case, a large amount of 15 &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{\mu{m}}$&lt;/span&gt; radiation that the soil emits will be absorbed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Will the temperature of this only-&lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; atmosphere increase? I think so, but in this case the atmosphere would not be able to re-emit IR in the 15 &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{\mu{m}}$&lt;/span&gt; band but would emit black body radiation that depends on the temperature reached by absorbing 15 &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{\mu{m}}$&lt;/span&gt; IR.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To sum up, does &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; act as a mirror and reflect 15 &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{\mu{m}}$&lt;/span&gt; IR or does it absorb this wavelength and transform it into heat and then emits it like a black body? What is &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{CO_2}$&lt;/span&gt; albedo to 15 &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{\mu{m}}$&lt;/span&gt; wavelength?&lt;/p&gt;&#xA;" OwnerUserId="18493" LastEditorUserId="2470" LastEditDate="2020-01-02T18:54:58.960" LastActivityDate="2020-01-02T18:54:58.960" Title="CO2 behaviour in atmosphere" Tags="|atmosphere|co2|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18728" PostTypeId="1" CreationDate="2019-12-18T00:31:56.647" Score="2" ViewCount="529" Body="&lt;p&gt;I'm a novice software developer who's about to write some Python scripts for getting weather data from several U.S. stations, as well as a few in the Pacific (for checking Southern Oscillation Index &amp;amp; the like).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've been oriented toward NOAA's site mostly, but having seen some mentions about 'European models' of weather forecasting in various articles over the past year, I wonder if it would be better to look toward mining the ECMWF.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Basically, I'm looking at current surface temperature and wind speeds, then trying to get a daily forecast out to 15-20 days forward. Haven't dug into ECMWF yet, but on NOAA's site, they do provide probabilistic outlooks, albeit on a monthly frequency (&lt;a href=&quot;https://w2.weather.gov/climate/outlook.php?redir=1&amp;amp;wfo=lot&amp;amp;site=111549&amp;amp;lead=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;example&lt;/a&gt;). I could always check weather.com's 10-Day or Monthly, but again, I'm wondering about the accuracy.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyone with experience comparing forecasted vs actual results on a thorough basis, and can share some perspective?&lt;/p&gt;&#xA;" OwnerUserId="18498" LastActivityDate="2019-12-18T08:56:08.253" Title="ECMWF vs NOAA forecast data accuracy" Tags="|weather-forecasting|data-analysis|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18729" PostTypeId="2" ParentId="18483" CreationDate="2019-12-18T00:48:36.487" Score="1" Body="&lt;p&gt;Yes, the Appalachian Region would be considered a Temperate Rainforest based on a combination of rainfall numbers, humidity and temperatures. Its latitude runs from in the 30's and up to high 50's in latitude location north of the equator. Feeding the forest region are a combination of two damp air masses which rotate in a cyclonic rotation inward from the marine locations, namely the Maritime Tropical air mass bringing very humid air from the Gulf of Mexico and the cooler air but also damp Martime Polar air mass. The mountains, while lower in elevation than the Western Rocky Mountains, offer much of this damp air from either air mass to move over toward the mountains when the jetstream is positioned in a way to not influence these air masses in a way that pushes them eastward. Orographic type precipitation can occur as a result, but much of it in that region is frontal as the colder Contintental Polar and Arctic air masses tend to interact with the damp air masses mentioned previously dumping significant amounts of rainfall suddenly as I can attest in my many journeys through these mountains on my way to Georgia or Florida from Ontario. Given the rainfall alone and the fact there is a diverse complexity of vegetation and animal specie, I would surely believe that the Appalachian Region qualifies easily as a Temperate Rainforest. Climate graph &gt; location in Appalachian Region &lt;a href=&quot;https://en.climate-data.org/north-america/united-states-of-america/virginia/appalachia-135846/#climate-table&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.climate-data.org/north-america/united-states-of-america/virginia/appalachia-135846/#climate-table&lt;/a&gt;  and, location map of North American air masses paths running along and to this region &lt;a href=&quot;https://wordpress.accuweather.com/wp-content/uploads/2018/01/static-winter-air-masses-11-am-1.jpg?w=632&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://wordpress.accuweather.com/wp-content/uploads/2018/01/static-winter-air-masses-11-am-1.jpg?w=632&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18476" LastActivityDate="2019-12-18T00:48:36.487" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18730" PostTypeId="1" AcceptedAnswerId="18735" CreationDate="2019-12-18T06:54:20.887" Score="1" ViewCount="47" Body="&lt;p&gt;I read &lt;a href=&quot;https://www.tandfonline.com/doi/abs/10.3402/tellusa.v5i4.8697&quot; rel=&quot;nofollow noreferrer&quot;&gt;an article&lt;/a&gt; about atmosphere and the article has this sentence:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;At all events, however, they will cause an exchange of water molecules&#xA;  between the vapour and the droplet. If this exchange is extremely&#xA;  rapid, the O18-abundance in the droplet must correspond to that in the&#xA;  surrounding vapour. Whereas if the exchange is extremely slow the&#xA;  O18-abundance in the droplet will correspond with that of the vapour&#xA;  at the place where the droplet was formed, i.e., because of the&#xA;  oblique movement of the droplet, at a considerably lower level of the&#xA;  front.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Can you tell me what is the difference between rapid exchange and slow exchange? In these two circumstances, the O18-abundance in the droplet always correspond with that of the vapour.&lt;/p&gt;&#xA;" OwnerUserId="18500" LastEditorUserId="6" LastEditDate="2019-12-18T09:43:53.807" LastActivityDate="2019-12-18T09:43:53.807" Title="How to understand the sentence below about rapid or fast exchange between vapour and droplet?" Tags="|atmosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18731" PostTypeId="2" ParentId="17489" CreationDate="2019-12-18T07:38:34.603" Score="-1" Body="&lt;p&gt;I have a fork of the official WAFO repo that I use, having converted it to python 3 a year or so ago. I haven't updated it in a while and haven't tested all the functionality, but anyone still looking for this is welcome to try using:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;pip install https://github.com/JohnCHarrington/pywafo.git&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="18501" LastActivityDate="2019-12-18T07:38:34.603" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18732" PostTypeId="2" ParentId="18728" CreationDate="2019-12-18T08:22:57.833" Score="3" Body="&lt;p&gt;You can compare verification scores using &lt;a href=&quot;https://apps.ecmwf.int/wmolcdnv/scores/mean/msl&quot; rel=&quot;nofollow noreferrer&quot;&gt;this application from ECMWF&lt;/a&gt; made from guidelines by the WMO. The example below fits nicely with what is widely known, namely that IFS (the ECMFWF global model) scores generally best. In recent year the UK Met Office global model have also scored better than GFS. The figure shows the root mean square error of MSLP.&#xA;The example below of course only covers verification for one month, so you should examine longer periods and focus on the fields you are most interested in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ruiSm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ruiSm.png&quot; alt=&quot;Verification for MSLP&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17522" LastEditorUserId="17522" LastEditDate="2019-12-18T08:56:08.253" LastActivityDate="2019-12-18T08:56:08.253" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18733" PostTypeId="1" CreationDate="2019-12-18T08:49:24.867" Score="1" ViewCount="396" Body="&lt;p&gt;I plotted the atmospheric CO2-concentrations to see trends and wondered especially about the phase around 1600 in the plot which I find very interesting. Etienne Godin already told me some facts in the comments of another thread, but I'm curious about more details, since I'm a newbie in this area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2QxYZ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2QxYZ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;source: &lt;a href=&quot;https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/frank2010/smoothedco2.txt&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www1.ncdc.noaa.gov/pub/data/paleo/contributions_by_author/frank2010/smoothedco2.txt&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where I plotted the column ALL_50_full.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What do you say?&lt;/p&gt;&#xA;" OwnerUserId="18482" LastEditorUserId="18482" LastEditDate="2019-12-20T13:44:45.723" LastActivityDate="2019-12-20T13:44:45.723" Title="Trends in atmospheric CO2" Tags="|atmosphere|climate-change|co2|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18735" PostTypeId="2" ParentId="18730" CreationDate="2019-12-18T09:05:28.357" Score="1" Body="&lt;p&gt;The wording is not clear, but here is what I understand:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In case of extremely rapid exchange of molecules between the droplet and the surrounding vapour, the droplet gets the same O&lt;sup&gt;18&lt;/sup&gt; abundance as the vapour because they reach equilibrium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In case of extremely slow exchange of molecules between the droplet and the surrounding vapour, the droplet keeps the O&lt;sup&gt;18&lt;/sup&gt; abundance that the vapour had &lt;em&gt;where the droplet was formed&lt;/em&gt;. This is a different location (lower in the front, as shown by figure 2), so the abundance can also be different.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2019-12-18T09:05:28.357" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18740" PostTypeId="1" CreationDate="2019-12-18T18:01:10.940" Score="4" ViewCount="119" Body="&lt;p&gt;Does the ideal gas law, PV=nRT, mean that isobars on a map of surface conditions are also isotherms?  Is there a way to intuit isotherms from isobars, and vice versa?&lt;/p&gt;&#xA;" OwnerUserId="18507" LastEditorUserId="18507" LastEditDate="2019-12-18T21:05:43.303" LastActivityDate="2019-12-19T17:10:20.107" Title="Does PV=nRT mean that isobars are also isotherms?" Tags="|meteorology|atmosphere|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18741" PostTypeId="2" ParentId="18721" CreationDate="2019-12-18T18:21:00.300" Score="2" Body="&lt;p&gt;Neither an answer, just common sense.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not sure if anybody can give exact numbers for temperatures of future heat waves in their projections. Predictions are difficult, especially those regarding the future. But there is consensus and now observation that heatwaves become more frequent and hotter &lt;a href=&quot;http://not%20only%20on%20land&quot; rel=&quot;nofollow noreferrer&quot;&gt;not only on land&lt;/a&gt;. One could perform a search for publications that deal with the impact of land heatwaves, e.g. on agriculture (wheat for example), desertification, loss of habitable space, flooding, loss of resources like potable water, etc. There is a lot of published work around.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We went past the 1°C warming compared to pre industrial levels in 2015, after [&lt;a href=&quot;https://www.ncdc.noaa.gov/cag/global/time-series]&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncdc.noaa.gov/cag/global/time-series]&lt;/a&gt; and many publications. Current estimations range between 0.9 and 1.6°C for 2019. Several islands have been devastated in the past years, damage still not totally repaired. Jakarta is drowning, catastrophic fires in California, Australia and elsewhere, fed by drought, heat and mismanagement, cost lives and property.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The effect of past and current heatwaves on the health of the population is pretty well visible, western European countrie's and the US health departments have published their estimations of fatalities attributed to heat.&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user18411" LastEditDate="2019-12-18T18:44:42.563" LastActivityDate="2019-12-18T18:44:42.563" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18742" PostTypeId="2" ParentId="10160" CreationDate="2019-12-18T19:34:19.803" Score="3" Body="&lt;p&gt;I was recently on the hunt for comprehensive values of water, CO&lt;sub&gt;2&lt;/sub&gt; and energy per kcal of various foods. I found this post useful along the way, although I ended up using some other sources that had a larger variety of foods to create my own list.&lt;/p&gt;&#xA;&lt;p&gt;The table of my findings (sources at the bottom) is attached here. Enjoy!&#xA;&lt;a href=&quot;https://i.stack.imgur.com/4NxeR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4NxeR.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18508" LastEditorUserId="2470" LastEditDate="2022-05-20T17:46:01.457" LastActivityDate="2022-05-20T17:46:01.457" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18743" PostTypeId="1" AcceptedAnswerId="18745" CreationDate="2019-12-18T20:53:47.263" Score="1" ViewCount="1158" Body="&lt;p&gt;I was trying to understand why &lt;a href=&quot;https://www.quora.com/Why-is-New-Zealand-called-New-Zealand&quot; rel=&quot;nofollow noreferrer&quot;&gt;there are no snakes in New Zealand&lt;/a&gt; and at same time I see snakes are &lt;a href=&quot;https://sciencing.com/importance-snakes-ecosystem-8078550.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;important for ecosystems&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my question is how New Zealand's ecosystem is surviving without snakes?&lt;/p&gt;&#xA;" OwnerUserId="18509" LastEditorUserId="2470" LastEditDate="2019-12-19T02:51:48.690" LastActivityDate="2019-12-19T02:51:48.690" Title="Why are there no snakes in New Zealand when ecosystem needs them" Tags="|ecology|" AnswerCount="1" CommentCount="3" ClosedDate="2019-12-19T06:14:39.480" ContentLicense="CC BY-SA 4.0" />
  <row Id="18744" PostTypeId="2" ParentId="18733" CreationDate="2019-12-18T22:45:10.417" Score="-1" Body="&lt;p&gt;One theory:&lt;br&gt;&#xA;&lt;a href=&quot;https://www.vice.com/en_us/article/bjqnqq/european-genocide-of-indigenous-peoples-in-the-americas-cooled-earths-climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;European Genocide of Indigenous Peoples in the Americas Cooled Earth’s Climate&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The mass deaths of Indigenous American peoples 500 years ago—caused by disease and violence spread by European colonizers—was so extreme that it cooled Earth’s climate, according to a new study in Quaternary Science Reviews.&lt;br&gt;&#xA;  Led by Alexander Koch, a graduate student in geography at University College London, the authors said that a period of global cooling that lasted from the 16th to 19th centuries was partly caused by epidemics and warfare that killed 90 percent of the Indigenous population in just 100 years.&lt;br&gt;&#xA;  The devastating loss, known as the Great Dying, left 56 million hectares of farmland unattended, enabling forests and other vegetation to grow over agricultural terrains. The rewilded landscapes drank in much more carbon dioxide than the preceding farms, which reduced levels of the greenhouse gas in the atmosphere by 7-10 parts per million.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Original research this article references:&lt;br /&gt;&#xA;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0277379118307261&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth system impacts of the European arrival and Great Dying in the Americas after 1492&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="595" LastEditDate="2019-12-19T12:44:45.680" LastActivityDate="2019-12-19T12:44:45.680" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18745" PostTypeId="2" ParentId="18743" CreationDate="2019-12-18T23:21:50.420" Score="-4" Body="&lt;p&gt;Snakes are important in some ecosystems because they keep down vermin, but the natives of these places pay a high price for this service. Why does new Zealand not have any? Maybe like Ireland there was a water barrier preventing snakes from reaching the islands. Australia is swarming with snakes, most of them very poisonous, but maybe it wasn't when New Zealand broke free many millions of years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another possibility is that there were once a few snakes in New Zealand, but predators like the Giant Moa and its relatives, and snake-eating birds of prey, might have hunted them to extinction. As for Ireland, snakes were killed off or driven out by the Ice Age, and when the ice receded the snakes from Europe were too slow to get there before the Irish Sea was formed. Only three species manged to reach England before it was cut off by the Channel. Snakes are not important for British ecosystems, but not many people would like to see them become extinct here. Only one, the adder, is poisonous, and kills about one person every fifty years. Just as British ecosystems could survive quite happily without snakes, so can New Zealand. To introduce even harmless ones there could risk a similar eco-disaster to the one in Australia caused by the introduction of the cane toad.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-18T23:21:50.420" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18746" PostTypeId="2" ParentId="18733" CreationDate="2019-12-19T13:48:00.570" Score="1" Body="&lt;p&gt;Since CO2 concentration is responsible of temperature, that trend is related to &lt;a href=&quot;https://en.wikipedia.org/wiki/Little_Ice_Age#Possible_causes&quot; rel=&quot;nofollow noreferrer&quot;&gt;the little ice age&lt;/a&gt;, where Earth cooled a little. Wikipedia article describes several possible causes for that, one of the is the answer of Keith, but others might be orbital cycles, solar activity, volcanic activity and ocean circulation.&lt;br&gt;&#xA;Also is possible that is just a &lt;a href=&quot;https://en.wikipedia.org/wiki/Bond_event&quot; rel=&quot;nofollow noreferrer&quot;&gt;cycle&lt;/a&gt; that repeats itself each 1000 or 1500 years.&lt;/p&gt;&#xA;" OwnerUserId="5004" LastActivityDate="2019-12-19T13:48:00.570" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18747" PostTypeId="1" CreationDate="2019-12-19T13:53:58.117" Score="1" ViewCount="28" Body="&lt;p&gt;Does losing moisture of a cored rock sample will increase its strength? Or drying out make the core specimen weaker. If the rock is a clayey rock, it will be weaker. But  what about for other rocks? Will their strength in uniaxial compressive strength test or point load test increase when comparing its strength with its in situ conditions, Say its under 100 m of the ground level and saturated.&lt;/p&gt;&#xA;" OwnerUserId="15195" LastActivityDate="2019-12-19T13:53:58.117" Title="Does the strength of a rock cored from a borehole increase while waiting in atmospheric conditions?" Tags="|geoengineering|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18748" PostTypeId="2" ParentId="18740" CreationDate="2019-12-19T17:10:20.107" Score="3" Body="&lt;p&gt;No. After a bit of mathematics, and the inclusion of water vapor, you can also get &lt;span class=&quot;math-container&quot;&gt;$P=\rho_d R_dT_v$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$\rho_d$&lt;/span&gt; is the dry air density and &lt;span class=&quot;math-container&quot;&gt;$R_d$&lt;/span&gt; is the specific gas constant for dry air, and &lt;span class=&quot;math-container&quot;&gt;$T_v$&lt;/span&gt; is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Virtual_temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;virtual temperature&lt;/a&gt;. So isobars are more than just isotherms- they are also dependent on density and water vapor. Check out &lt;a href=&quot;https://en.wikipedia.org/wiki/Ideal_gas_law#Molar_form&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia's derivation&lt;/a&gt; for the proof that &lt;span class=&quot;math-container&quot;&gt;$PV=nRT$&lt;/span&gt; is the same as &lt;span class=&quot;math-container&quot;&gt;$P=\rho RT$&lt;/span&gt;, and then use the fact that &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; has both dry air and water vapor, to get &lt;span class=&quot;math-container&quot;&gt;$P=\rho_d R_dT_v$&lt;/span&gt;.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2019-12-19T17:10:20.107" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18749" PostTypeId="2" ParentId="18098" CreationDate="2019-12-19T20:57:33.590" Score="2" Body="&lt;p&gt;Climate science seems to be as relevant as other types of science. It's just that it has been organized ridiculed after the formation of IPCC in the 80's. It has a lot of heritage from physics and there are a lot of signs of a climate emergency.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CLy3b.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CLy3b.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pBQt0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pBQt0.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your question is not fully clear. Some effects are impossible to predict in detail while other is not. Down a prediction of the global temperature and the concentration of atmospheric CO₂ made by ExxonMobile's researcher 1980.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/juJLi.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/juJLi.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="16809" LastEditorUserId="16809" LastEditDate="2019-12-20T13:20:22.683" LastActivityDate="2019-12-20T13:20:22.683" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18750" PostTypeId="1" CreationDate="2019-12-20T00:10:26.930" Score="4" ViewCount="2625" Body="&lt;p&gt;In the US, when constructing a geothermal heat pump, common knowledge holds that anywhere in the country the subsurface ground temperature at a depth of 5 m will be around 10 to 15 C, which is a good temperature to provide cooling in summer and heating in winter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was trying to find information on subsurface temperatures at various depths around the world -- I had assumed that this value would be fairly consistent, but I am unable to confirm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;How does subsurface temperature vary around the world (say at a depth of 5 to 10 m), and what does this depend on?&lt;/strong&gt; I am not concerned about the effect of local phenomenon such as volcanic activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'd be particularly interested in a map (static or interactive) presenting this information.&lt;/p&gt;&#xA;" OwnerUserId="7741" LastActivityDate="2019-12-20T19:27:02.353" Title="How does the subsurface earth temperature vary around the world?" Tags="|temperature|geothermal-heat|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18751" PostTypeId="2" ParentId="18750" CreationDate="2019-12-20T05:52:02.430" Score="5" Body="&lt;p&gt;The subsurface temperature will vary due to the soil type: sand, clay, loam, silt and the degree of saturation of the soil, soil thickness, the thermal conductivity of the soil, the surface temperature (time of the year) and the &lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/soil-temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;albedo of the surface&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Temperature changes within soil become less variable with depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far I have only found information for two regions: the &lt;a href=&quot;https://builditsolar.com/Projects/Cooling/EarthTemperatures.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;US-Virgina&lt;/a&gt; and &lt;a href=&quot;https://www.researchgate.net/publication/30500372_Measurements_of_Ground_Temperature_at_Various_Depths&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cyprus&lt;/a&gt;. Following is a series of curves for the US. A similar diagram is available for Cyprus, but its locked in a pdf file.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Cyprus, the soil temperature at 3 m depth varies between 18 °C and 20 °C. In the US, at a depth of 12 feet (3.6 m) the temperature varies between 60 °F and 65 °F (15.5 °C and 18.3 °C).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These results are similar, but it needs to be noted both locations are in temperate climate zones. The latitudinal extent of Virginia is between 36.5° and 39.5° North and Cyprus is 35° North.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UMeiM.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UMeiM.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From research undertaken in &lt;a href=&quot;https://pangea.stanford.edu/ERE/db/WGC/papers/WGC/2015/11046.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Australia&lt;/a&gt;, the temperature at depth in a soil is also dependent on the air temperature and hence the latitude. At a depth of 1 m the soil temperature is 35 °C at latitude 10° South and 12 °C at latitude 45° South. There will be a corresponding difference at 5 to 10 m depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Spq5D.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Spq5D.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.bgs.ac.uk/reference/gshp/gshp_report.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;British Geological Survey&lt;/a&gt; states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;About half of the solar radiation received by the Earth is absorbed at the surface. As a result, the ground temperature shows seasonal fluctuations to depths of about 15 m where the temperature is approximately equal to the mean annual air temperature(8 - 11° C in the UK). Below this the ground temperature increases at, on average, 2.6 °C per 100 m due to heat flowing from the interior of the Earth. Mean temperatures at 100 m depth in the UK vary between about 7 - 15°C.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2019-12-20T19:27:02.353" LastActivityDate="2019-12-20T19:27:02.353" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18752" PostTypeId="1" AcceptedAnswerId="18754" CreationDate="2019-12-20T14:47:48.493" Score="1" ViewCount="341" Body="&lt;p&gt;Mars have several mountains above 10 km, with the highest being around 22 km (full list for Solar System &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_tallest_mountains_in_the_Solar_System&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;). Same for Io, Jupiter's moon. In contrast, the Earth has no mountain higher than 10.2 km (Manua Kea and Manua Loa, when considered from the bottom  of the ocean, more comparable with mars and Io), with the Everest being 8.8 km above sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any &lt;strong&gt;restriction&lt;/strong&gt; in terms of the geological nature of Earth, or perhaps due to the atmosphere (e.g. water cycle/erosion), or closeness to the Sun (Mercury and Venus have even smaller mountains), that doesn't allow for higher mountains on Earth? Or is it perhaps just a matter of age? (in the sense that future tectonic movements will lead to higher mountains, without a particular limit)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More generally, &lt;strong&gt;is there any physical limit about how high mountains on this planet can ever be?&lt;/strong&gt; &lt;/p&gt;&#xA;" OwnerUserId="13541" LastActivityDate="2019-12-20T17:36:17.873" Title="Why are there no mountains higher than ~10 km?" Tags="|mountains|earth-system|" AnswerCount="1" CommentCount="1" ClosedDate="2019-12-20T17:44:14.763" ContentLicense="CC BY-SA 4.0" />
  <row Id="18753" PostTypeId="1" AcceptedAnswerId="18766" CreationDate="2019-12-20T14:55:41.400" Score="7" ViewCount="152" Body="&lt;p&gt;I am working on a project. Where this bacteria has been deposited at a port in the Humber Estuary. Where it has been deposited has been marked in red. I am trying to work out the limits of where this bacteria can get moved to. I know that the input of all freshwater by the rivers is 250 m3 per second so I could calculate the movement of the bacteria as it leaves the estuary. However, I want to work out if it can be moved inland by the tide. I have found some information that looks at tide velocities. However, the velocity seems pretty low compared to the amount of freshwater entering the estuary. The thing is the points of tidal incursion are marked on the map so I assume the tide reaches there, especially as the tide can increase the height of the river by metres in some places. I am struggling to know what information I need to calculate this because I am more a biologist by training.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any help would be appreciated!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;&#xA;&lt;p&gt;James&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eg9mK.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eg9mK.png&quot; alt=&quot;Humber Estuary (bacteria deposit marked it red)&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jSpci.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jSpci.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18521" LastActivityDate="2019-12-22T23:45:43.217" Title="Tidal flow in an estuary" Tags="|water|rivers|tides|estuary|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18754" PostTypeId="2" ParentId="18752" CreationDate="2019-12-20T17:36:17.873" Score="2" Body="&lt;p&gt;The reason mountains are higher on Mars than on Earth is the lower gravity on Mars, which is only one third of Earth gravity. Mountains are very heavy things, and on Earth the forces that build them have to fight against gravity, which is constantly trying to drag them down. For the same reason, small asteroids are usually not spherical, because they don't have enough gravity to even out the bumps, but when they get to about the size of Ceres, which is 500 miles in diameter, they do. Ceres is spherical. Mountains like Mauna Kea which have a large part under water don't count, because although mountains are heavy things they still have buoyancy and the sea is taking part of their weight. Venus has slightly less gravity than Earth, but because of the enormous heat is also more plastic, so this would mitigate against the building of very high mountains. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-20T17:36:17.873" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18756" PostTypeId="1" AcceptedAnswerId="18765" CreationDate="2019-12-21T17:47:46.840" Score="3" ViewCount="160" Body="&lt;p&gt;What kind of salt is used to keep roads from getting icy and how does it work?&#xA;Why does ice get thick in some places and other nearby places there is no ice?&lt;/p&gt;&#xA;" OwnerUserId="5771" LastEditorUserId="543" LastEditDate="2019-12-21T17:58:06.017" LastActivityDate="2019-12-23T23:29:00.883" Title="How does salting roads help prevent ice?" Tags="|snow|ice|transportation|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18757" PostTypeId="2" ParentId="18756" CreationDate="2019-12-21T19:09:23.153" Score="2" Body="&lt;p&gt;The kind of salt used to keep roads ice-free is rock salt. Rock salt is an evaporite, which was once a salt lake like the one near Salt Lake City in Utah called Bonneville Salt Flats. In the course of millions of years, many salt evaporite deposits have become buried deep underground. A mine typically produces thousands of tons per year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason it works is that salt water has a lower freezing point than fresh water, so fresh water precipitation such as rain or snow will easily freeze in the sort of night-time winter temperatures they have in UK, for example. As salt water freezes at lower temperatures than are usually encountered in UK, roads which have been salted usually remain clear. Icy roads are dangerous, and cause traffic accidents, so when freezing conditions are forecast the municipal authorities have vehicles which drive around spraying the road and sometimes sidewalks with rock salt. Most rock salt has natural grit mixed with it, which also helps prevent vehicles skidding.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason you might get clear roads in some places while there is ice nearby is that the spraying of the roads is not always even, and some small areas are missed. Another reason is that having been salted, the even spread of salt is spoiled by rain showers, which remove it from some places and concentrate it in others. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-21T19:09:23.153" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="18758" PostTypeId="1" AcceptedAnswerId="18759" CreationDate="2019-12-22T07:50:34.810" Score="5" ViewCount="1377" Body="&lt;p&gt;I am trying to regrid some of my latitude-longitude grid files to tripolar ocean grid and found that ESMF can be useful. However, I am finding it hard to install the same. &lt;/p&gt;&#xA;" OwnerUserId="18429" LastActivityDate="2020-05-01T17:27:53.187" Title="How to install ESMF and ESMFPy in Ubuntu using gfortran, gcc, python?" Tags="|meteorology|numerical-modelling|atmospheric-circulation|ocean-models|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18759" PostTypeId="2" ParentId="18758" CreationDate="2019-12-22T08:02:10.867" Score="7" Body="&lt;p&gt;First download the esmf tar file from &lt;a href=&quot;http://www.earthsystemmodeling.org/esmf_releases/public/ESMF_7_1_0r/reg/ESMF_Framework_Down.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.earthsystemmodeling.org/esmf_releases/public/ESMF_7_1_0r/reg/ESMF_Framework_Down.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then install netcdf library and gfortran compiler using&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;sudo apt-get install git tcsh pkg-config&#xA;sudo apt-get install gfortran&#xA;sudo apt-get install netcdf-bin libnetcdf-dev libnetcdff-dev&#xA;sudo apt-get install openmpi-bin libopenmpi-dev&#xA;sudo apt-get install libnetcdff-dev&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Once you have the netcdf library and gfortran compiler in your /usr/local/lib and /usr/local/include You can check this also, login as root using&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;sudo -i&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Then define the following environment variables&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cd path_of_esmf_dir&#xA;export ESMF_DIR=path_of_esmf_dir&#xA;export ESMF_INSTALL_PREFIX=/usr/local/esmf&#xA;export ESMF_OS=Linux&#xA;export ESMF_NETCDF=&quot;local&quot;&#xA;export ESMF_COMM=mpiuni&#xA;export ESMF_F90COMPILER=gfortran&#xA;export ESMF_CXXCOMPILER=g++&#xA;export ESMF_TESTEXHAUSTIVE=on&#xA;export ESMF_TESTSHAREDOBJ=on&#xA;export ESMF_NETCDF_INCLUDE=/usr/local/include&#xA;export ESMF_NETCDF_LIBS=&quot;-lnetcdf -lnetcdff&quot;&#xA;export ESMF_NETCDF_LIBPATH=/usr/local/lib&#xA;export ESMF_BOPT=O3&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Then run the following syntax to make the library ESMF&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;make all&#xA;make install&#xA;make installcheck&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Now to install the ESMF python library&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cd path_to_esmf_dir/addon/ESMpy/&#xA;python setup.py build --ESMFMKFILE=/usr/local/esmf/lib/libO3/Linux.gfortran.64.mpiuni.default/esmf.mk&#xA;python setup.py install&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;You can check the installation by &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;$ python &#xA;&amp;gt;&amp;gt;&amp;gt; import ESMF&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;ESMF python library has got limited features as compared to the ESMF library. Hence it is better to use ESMF directly.&lt;/p&gt;&#xA;" OwnerUserId="18076" LastEditorUserId="18076" LastEditDate="2020-04-21T19:34:14.283" LastActivityDate="2020-04-21T19:34:14.283" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18760" PostTypeId="2" ParentId="18718" CreationDate="2019-12-22T09:11:32.203" Score="2" Body="&lt;p&gt;&quot;&lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/0521796296&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atmospheric modeling, data_assimilation and predictability&lt;/a&gt;&quot; by Euginia Kalnay, is an introductory book, which is good to get an overall overview of the subject.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are more interested in the numerics I would recommend &quot;&lt;a href=&quot;https://www.springer.com/gp/book/9781441964113&quot; rel=&quot;nofollow noreferrer&quot;&gt;Numerical Methods for Fluid Dynamics&lt;/a&gt;&quot; by Dale R. Durran.&lt;/p&gt;&#xA;" OwnerUserId="17522" LastActivityDate="2019-12-22T09:11:32.203" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18761" PostTypeId="1" AcceptedAnswerId="18764" CreationDate="2019-12-22T14:01:06.810" Score="3" ViewCount="71" Body="&lt;p&gt;During the rainy season, the crops like corn, cotton are found to be growing faster. Studies shows that the thermoelectric fixation of gaseous Nitrogen during rain storm accelerates the plants growth in rainy season. &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Can this effect be seen in Sprinkler irrigation ?&lt;/li&gt;&#xA;&lt;li&gt;Is it possible to mimic this effect in other irrigation methods?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="18320" LastActivityDate="2019-12-22T17:44:01.617" Title="Rain Water vs Sprinkler Irrigation" Tags="|geophysics|climate|rain|nitrogen|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18762" PostTypeId="2" ParentId="18098" CreationDate="2019-12-22T14:59:48.840" Score="2" Body="&lt;p&gt;Climate is not weather, and modeling the climate is not like modeling the weather, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/20/what-are-the-major-differences-between-weather-models-and-climate-models&quot;&gt;What are the major differences between weather models and climate models?&lt;/a&gt;. In the same way modeling the movement of a single animal over its lifetime at a meter scale is very different than measuring and predicting population change over several generations. Or how trying to predict the erosion of a beach is much easier than trying to predict the movement of a single sand grain. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A climate model is in many ways a much simpler system to model because you are not trying to predict individual local wind patterns or exact local evaporation. As the linked answer puts it, &quot;a weather model cares where a hurricane is, and when/where it will impact land, whereas a climate model may only care the average number of hurricanes per year and not about where the details of those storms).&quot; Scale is a big factor and many thing become easier to predict at a wider scale. At the same time a climate model incorporate many more factors, many thing in weather models are simply left out since they don't change or are not a factor at the scale of the model, even important things like the fact the earth is a round and soils release gases. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2019-12-22T15:06:30.183" LastActivityDate="2019-12-22T15:06:30.183" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18764" PostTypeId="2" ParentId="18761" CreationDate="2019-12-22T17:44:01.617" Score="2" Body="&lt;p&gt;I think what you mean by thermo-electric nitrogen fixation is the nitric oxides created by lightning discharges. This is absorbed by the raindrops as they form and as they fall to earth, and helps to fertilise the soil. You won't get this effect with sprinkler irrigation to any great extent, because the water droplets are exposed to the nitrogen oxides for far less time. In addition, sprinkler use is not usually accompanied by lighting flashes, whereas rain sometimes is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If your crops are watered mainly by sprinklers and you would like them to have more nitrogen, you should practice rotation of crops. Some years you plant legumes, which fix nitrogen by means of the nitrogen-fixing bacteria which live in the nodules in their roots. In the tropics, a kind of acacia called mimosa, though not related to legumes, has the same nitrogen-fixing capability. This acacia is sometimes called 'the sensitive plant', as when touched its leaves rapidly fold themselves away.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-22T17:44:01.617" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18765" PostTypeId="2" ParentId="18756" CreationDate="2019-12-22T23:30:04.797" Score="6" Body="&lt;p&gt;Sodium chloride rock salt, NaCl, is usually used for de-icing roads. As mentioned in another answer, the dissolved ions lower the freezing point of water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other kinds of salt are also used. Calcium chloride, CaCl2, is more efficient at melting ice. NaCl can not melt ice at temperatures lower than -18C (0 F). A saturated calcium chloride solution won't freeze until ~ -46 C. Calcium chloride is often applied as a solution because the solid becomes sticky as it absorbs water from the air.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: per the &lt;a href=&quot;https://www.codot.gov/travel/winter-driving/faqs.html#kindsOfRoadTreatments&quot; rel=&quot;nofollow noreferrer&quot;&gt;link to the Colorado road dept&lt;/a&gt; from a comment on another answer, magnesium chloride is used in the liquid deicers. Here is a &lt;a href=&quot;https://www.oxycalciumchloride.com/sidewalk-ice-melting/effective-ice-melting/how-to-melt-ice-effectively/choosing-the-right-deicer&quot; rel=&quot;nofollow noreferrer&quot;&gt;link to information on different deicers&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1242" LastEditorUserId="1242" LastEditDate="2019-12-23T23:29:00.883" LastActivityDate="2019-12-23T23:29:00.883" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18766" PostTypeId="2" ParentId="18753" CreationDate="2019-12-22T23:45:43.217" Score="0" Body="&lt;p&gt;The tidal flow velocity is not the same thing as the mass movement. Think of the tidal flow as a pressure pulse that moves up the river. It moves much farther than the actual salt water movement. The extent of the brackish zone is much shorter. The relationship depends on the river flow and the shape of the estuary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In your case, your source area is within the limit of saline intrusion so there is some mass movement upstream. Given that you are studying bacteria particles rather than dissolved salt, I would say that the limit of saline intrusion marked on your map is an upper limit for the distance it could move upstream. That is assuming that the bacteria haven't established a stable population that can reproduce and grow outward. &lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2019-12-22T23:45:43.217" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18767" PostTypeId="1" AcceptedAnswerId="18771" CreationDate="2019-12-23T01:37:38.537" Score="15" ViewCount="4418" Body="&lt;p&gt;If I understand the information from this link correctly,&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Instrumental_temperature_record&quot; rel=&quot;nofollow noreferrer&quot;&gt;Instrumental temperature record&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;between 1950 to 1980 there were negative temperature anomalies in the years of those decades.&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th&gt;decade&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;difference (°C)&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;difference (°F)&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;1950–1959&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;−0.02&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-0.0360&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;1960–1969&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;−0.014&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;−0.0252&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;1970–1979&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;−0.001&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;−0.0018&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;&#xA;&lt;p&gt;This seems odd considering massive oil consumption started in 1880 IIRC, and by 1980 over 350 billions of oil barrels were already consumed (much more probably, since the data before 1950 isn't considered because there weren't reliable records).&lt;/p&gt;&#xA;&lt;p&gt;Why was there a negative temperature anomaly between 1950 to 1980?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastEditorUserId="2958" LastEditDate="2021-04-19T22:49:31.067" LastActivityDate="2021-04-19T22:49:31.067" Title="Why was there a negative temperature anomaly between 1950 to 1980?" Tags="|climate-change|temperature|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18768" PostTypeId="1" AcceptedAnswerId="18770" CreationDate="2019-12-23T05:28:03.267" Score="5" ViewCount="13739" Body="&lt;p&gt;Would man-made steel artifacts be able to be preserved like fossils for millions of years, or would corrosion make them dissipate? What about metals such as aluminum that don't corrode as easily?&lt;/p&gt;&#xA;" OwnerUserId="18531" LastEditorUserId="2470" LastEditDate="2023-02-13T13:46:50.940" LastActivityDate="2023-02-13T13:46:50.940" Title="How long could a steel artifact last?" Tags="|geology|" AnswerCount="5" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="18770" PostTypeId="2" ParentId="18768" CreationDate="2019-12-23T06:54:39.863" Score="8" Body="&lt;p&gt;The short answer is no.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most metals do not fossilize well, they are too reactive/water soluble. Metals are usually what is doing the fossilizing, dissolved metal in groundwater is being attracted to the electrical properties of organic material and filling in or swapping places with a porous material. You might have a stain left or some of the shape as a natural casting, but not material preserved. The exception might be in amber, but it could also be really bad: amber preservation is tricky chemistry, so I am not comfortable saying yes or no. Metal objects have good short term preservation but horrid long term preservation. there are some low reactivity metals that might survive like gold, but not as fossils. But even gold is water soluble over millions of years, so even that would require some unusual conditions. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorDisplayName="user824" LastEditDate="2019-12-23T16:26:48.077" LastActivityDate="2019-12-23T16:26:48.077" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18771" PostTypeId="2" ParentId="18767" CreationDate="2019-12-23T09:52:40.670" Score="24" Body="&lt;p&gt;This phenomenon is known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Global_dimming&quot; rel=&quot;noreferrer&quot;&gt;global dimming&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It was due to the particles and aerosols mostly released by combustion of fossil fuels such as diesel. Those particles block the radiation from the sun, so they have a cooling effect. For some decades this effect counterbalanced the warming effect of greenhouse gases, although it is no longer the case at a global scale (see for instance &lt;a href=&quot;https://doi.org/10.1029/2006GL028031&quot; rel=&quot;noreferrer&quot;&gt;Wild et al. 2007&lt;/a&gt;). Particles emission has been reduced thanks to better engines and new regulations, which stopped their masking effect on global warming. Which is a good thing since those particles have a serious impact on health.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2019-12-23T09:52:40.670" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="18772" PostTypeId="2" ParentId="18768" CreationDate="2019-12-23T11:38:52.520" Score="-1" Body="&lt;p&gt;It all depends on the conditions of fossilisation and the type of steel. Human flesh doesn't usually last long, but the Ice Man found cryogenically preserved in the Austrian Alps had been there for 5,000 years and would have been there for another few thousand if he hadn't been removed. Dinosaur proteins and DNA much older than that have been found.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Iron doesn't last long in damp conditions unless it is alloyed with another metal. The best stainless steel artefacts could fossilise under the right, non-acidic conditions. Copper, silver, gold, platinum and several other metals have been found fossilised in their pure, metallic state, so it follows that artefacts made of these metals could fossilise. Iron-nickel fragments of the famous Barringer meteorite in Arizona have been fossilised under the crater for at least 50,000 years and will probably (apart from the bits that have been removed) stay there for millions of years longer in an almost pristine state.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Aluminium may not corrode as readily as iron, but it does corrode. Nevertheless, aluminium artefacts might fossilise under the right dry, non-acidic conditions, as there are plenty of even more remarkable examples of fossilisation known to science..&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-23T11:38:52.520" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18773" PostTypeId="2" ParentId="18767" CreationDate="2019-12-23T12:21:43.123" Score="11" Body="&lt;p&gt;Independently from dimming by aerosols, a change in the North Atlantic circulation pattern seemed  to have played a role. This might be connected to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Atlantic_multidecadal_oscillation&quot; rel=&quot;noreferrer&quot;&gt;multidecadal variability&lt;/a&gt; in sea surface temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/nature09394&quot; rel=&quot;noreferrer&quot;&gt;https://www.nature.com/articles/nature09394&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2019RG000644&quot; rel=&quot;noreferrer&quot;&gt;Newer work&lt;/a&gt; assumes that the role of aerosols may have been overestimated as a driver for the multidecadal variability. But then again, there may be &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018EF001052&quot; rel=&quot;noreferrer&quot;&gt;regional differences&lt;/a&gt; of the effect of such forcing.&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user18411" LastEditDate="2019-12-23T13:08:44.293" LastActivityDate="2019-12-23T13:08:44.293" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18774" PostTypeId="1" CreationDate="2019-12-23T13:33:25.957" Score="2" ViewCount="286" Body="&lt;p&gt;&lt;sup&gt;(This is about O₂, not CO₂)&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How did the concentration of oxygen change? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Over geologic time frames since plants began to produce it,&#xA;and during the time since the carbon dioxide increase caused by humans began is most interesting.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It would be most interesting to have an abstract description, even if simplified.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plots of the concentration over time are useful too, but not central.&lt;/p&gt;&#xA;" OwnerUserId="321" LastEditorUserId="321" LastEditDate="2019-12-23T13:52:11.780" LastActivityDate="2019-12-29T08:57:35.673" Title="What is the history of atmospheric O₂ concentration?" Tags="|geology|atmosphere|geochemistry|atmospheric-chemistry|oxygen|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18775" PostTypeId="2" ParentId="18534" CreationDate="2019-12-23T17:06:07.740" Score="5" Body="&lt;p&gt;Here's a take on calculating earth's thermal expansion and shrinking, under certain assumptions mentioned in the text. It seems to me, from a short overview, that the core is assumed to be constant over the time. It focuses on the mantle part of the earth, its mineral phases and convetion. Take it with a grain of salt:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S167498711200148X&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/S167498711200148X&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;tl,dr: after consolidation, earth's radius was 120km larger than today. It shrank by 110km in a few million years, then expanded a bit (11km), then contracted by 8km, and subsequently contracted by around 12km to the present day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If they say so :-)&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user18411" LastEditDate="2019-12-24T09:41:39.600" LastActivityDate="2019-12-24T09:41:39.600" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18777" PostTypeId="1" CreationDate="2019-12-23T19:20:39.727" Score="1" ViewCount="70" Body="&lt;p&gt;I'm not looking for college recommendations or which is the best, so I'm not asking for opinions on which institutions are the best. What I would like to know is if there are specific places that someone could go where they can just focus on geology related fields only. And only take classes that pertained to acquiring enough education to work in a geology related field.&lt;/p&gt;&#xA;" OwnerUserId="18522" LastActivityDate="2019-12-28T12:40:51.047" Title="Are there any geology only related educational institutions?" Tags="|geology|education|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18778" PostTypeId="2" ParentId="18768" CreationDate="2019-12-23T19:23:26.627" Score="6" Body="&lt;p&gt;When we speak of a fossil, we don't usually mean a preserved object, but rather a preserved trace of an object, like it's impression in other material. Metal objects certainly would leave impressions in the surrounding material, as well as oxides. So in that sense they can easily leave fossils. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whether the steel artifact its self lasts for eons depends on the specifics of the metal and the chemical and thermal conditions it encounters. But under most conditions, reactive metals like steel and aluminum would react away through multiple different corrosive mechanisms listed &lt;a href=&quot;https://tubingchina.com/Corrosion-mechanisms-in-stainless-steel-Tube.htm&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;. There's a very nice &lt;a href=&quot;https://tubingchina.com/Corrosion-Resistance-Table.htm&quot; rel=&quot;noreferrer&quot;&gt;table here&lt;/a&gt; of the rates of corrosion progression for a few types of steel alloy. This includes Hastalloy, which is one of the most corrosion resistant forms of steel and for that reason is commonly used in nuclear power plants. For industrial use, with &quot;Excellent Corrosion Resistance&quot; being less than 0.1 mm of corrosion progression per year. That rate of corrosion will eat through 100 meters of metal in a million years. Zinc-steal in contact with fresh water corrodes at a rate of at least &lt;a href=&quot;https://tubingchina.com/Corrosion-of-Zinc-Coated-Steel-in-Selected-Natural-Fresh-Waters.htm&quot; rel=&quot;noreferrer&quot;&gt;10 mm/year&lt;/a&gt;, which would rapidly destroy it over large time scales. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another way of looking at it is that basically all iron on Earth is found in the form of iron oxide, so iron compounds do not tend to stay oxidized over large time scales. Similarly, aluminum reacts with oxygen rapidly and is hardly ever (but not never) found in nature as an elemental metal. Some surface treatments such as anodization can extend this time, but will eventually fail. Some elemental metals can be found in nature, which is an indication that under some conditions they could be found as fossils. These &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Native_metal&quot; rel=&quot;noreferrer&quot;&gt;native metals&lt;/a&gt;&quot; particularly include copper, gold, silver and platinum-group metals (see link for a full list).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If, however, a reactive metal object is kept well away from oxygen and water it may last much longer. This is the case for satellites, although most satellites orbits are not entirely stable. The longest lasting may be those boosted into &lt;a href=&quot;https://en.wikipedia.org/wiki/Graveyard_orbit&quot; rel=&quot;noreferrer&quot;&gt;graveyard orbits&lt;/a&gt;; standard geosynchronous satellite graveyard orbit results in an expected orbital lifetime of millions of years. Objects on Mars stand a good chance of lasting for long time scales, since they are not exposed to air or water, and are kept cold with little thermal cycling. They are also likely to become buried in dust blown by the Martian wind. The Philae comet lander may be similarly preserved, though comets tend to crash into planets after a few million years. Similarly, several of the outer planet probes may last for extreme time scales since they will be in vacuum, cold, and safe from major collisions. In particular: Voyager 1 &amp;amp; 2, Pioneer 10 &amp;amp; 11, New Horizons. But these are continuously moving away from the solar system, so while preserved, won't leave any fossils to find.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In total, the answer appears to be eons, but few objects will find suitable conditions, and the best place to look will be on Mars. &lt;/p&gt;&#xA;" OwnerUserId="18534" LastActivityDate="2019-12-23T19:23:26.627" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18779" PostTypeId="2" ParentId="18774" CreationDate="2019-12-23T21:17:40.247" Score="0" Body="&lt;p&gt;There aere too many unknowns to give reliable figures for the varying levels of oxygen in the atmosphere in Precambrian times. What can be said with a fair degree of certainty is that photosynthetic cyanobacteria evolved about 3.5 billion years ago. At first the oxygen they produced was absorbed by the ocean, but by about 3 billion years ago it began to build up in the atmosphere. This led to the Great Oxygenation Event of almost 2.5 billion years ago which lasted some 250 million years and oxidised iron in the ocean, causing it to be deposited as rusty sediments and thus leaving a geological record of the event. About 1.5 billion years ago more advanced photosynthetic organisms evolved, but they were still microscopic. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We know that at the start of the Cambrian there was plenty of oxygen in the atmosphere and ocean, because primitive animal lifeforms which couldn't exist without it became abundant, but there was no one to take measurements so we can't give precise figures. It is said that by the late Carboniferous oxygen levels in the atmosphere may have been as high as 35 percent. One of the reasons given for this guestimate is the presence of giant-size dragonflies with a wingspan of about 2.5 feet, which it is theorised would have  needed such high levels of O2 in order to remain airborne. The atmosphere was probably denser at that time, which also would have made flight easier. Forests on land were making a large contribution to oxygen levels and burying carbon in the ground. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anthropogenic carbon dioxide in vast quantity happened only yesterday, and is a controversial topic, but it is still the photosynthetic life in the ocean which plays the major part in disposing of it and in the process generates oxygen.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-23T21:17:40.247" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18780" PostTypeId="1" AcceptedAnswerId="18803" CreationDate="2019-12-23T23:37:17.977" Score="1" ViewCount="227" Body="&lt;p&gt;We’ve completely obliterated our reliance on carbon based fuels. All our energy comes from renewal resources or even fusion. Our energy requirements continue to rise. Taking this to a deliberately ludicrous degree, whereby we’re capturing the sun’s energy, planet wide, via solar panels, we would essentially be diverting large amounts of sunlight that might otherwise have reflected our radiated back into space into our energy networks. Whatever that energy is used for our will ultimately be transformed Into heat. Some of that heat will be emitted into space via radiation, but I can’t help wondering if much of it will just stick around and continue to heat our atmosphere and oceans. Could our energy consumption increase indefinitely without affecting the ability of Earth to support our current ecosystem; or will be ultimately have to limit our energy use?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit for disambiguation purposes:&#xA;I'm not sure my original question at posed has been understood. Ignoring existing greenhouse gas emissions, in fact ignoring any issue with GHG at all, as civilization advances and our energy requirements continue to rise, the energy that we do use to perform work will ultimately be transformed into heat. We'd basically be pumping heat into the atmosphere instead of GHGs. A hotter atmosphere still holds more energy and moisture. Could we end up overproducing heat via fusion? Or is radiation an effective way for the planet to balance this excess?&lt;/p&gt;&#xA;" OwnerUserId="8119" LastEditorUserId="8119" LastEditDate="2019-12-24T23:57:36.840" LastActivityDate="2019-12-27T16:17:13.693" Title="In a zero carbon future but with increasing energy requirements would Earths oceans continue heating?" Tags="|atmosphere|climate-change|" AnswerCount="4" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18781" PostTypeId="2" ParentId="8692" CreationDate="2019-12-24T08:09:54.157" Score="0" Body="&lt;p&gt;Try to check the data, you have to arrange it from the highest value to the lowest value, and then use the phi formula to every data, that give the result from the lowest phi to the highest phi. So phi5 must be the lowest phi value and phi95 must be the highest phi value. Because the IGSD formula should be give result positive value.&lt;/p&gt;&#xA;" OwnerUserId="18539" LastEditorUserId="18081" LastEditDate="2019-12-25T05:01:10.297" LastActivityDate="2019-12-25T05:01:10.297" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18782" PostTypeId="2" ParentId="18780" CreationDate="2019-12-24T09:15:00.833" Score="-1" Body="&lt;p&gt;The great hope for a carbon neutral future is, as you suggest, fusion power stations. Scientists are making good progress in this direction, but a commercial reactor is still two or three decades away. We won't have to limit the number of reactors because their production of dangerous wastes is negligible compared to fission reactors. The heat they will produce is not a problem either, as it will be dwarfed by the heat from natural sources like the sun and geothermal. Much of the small contribution our reactors make will radiate away into space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We will have to limit our energy use for the simple reason that we will have to limit our population. The Earth does not have unlimited resources and populations cannot continue growing indefinitely. If we don't limit them ourselves in a planned and orderly way, nature will do it for us, and in the scramble for increasingly scarce resources, wars will become more likely. Water scarcity is already threatening to bring war to the Middle East and Africa. Whether the oceans will heat significantly before the carbon neutral energy sources can fully take up the task of providing our energy requirements, we shall have to wait and see.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-24T09:15:00.833" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18783" PostTypeId="2" ParentId="18780" CreationDate="2019-12-24T11:15:31.353" Score="2" Body="&lt;p&gt;Short answer: Yes, the ocean would continue heating for a while if we cut off all greenhouse emissions. Simply because CO2 has a &lt;a href=&quot;https://www.nature.com/articles/climate.2008.122&quot; rel=&quot;nofollow noreferrer&quot;&gt;long life&lt;/a&gt; span in the atmosphere and its effects will continue to be active for a long time, longer than human life spans.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, it may be that thresholds have already been passed that lead to &lt;a href=&quot;https://www.nature.com/articles/nclimate2568&quot; rel=&quot;nofollow noreferrer&quot;&gt;positive feedbacks&lt;/a&gt;, like glacier retreat or &lt;a href=&quot;https://www.nature.com/articles/ismej2016180&quot; rel=&quot;nofollow noreferrer&quot;&gt;desertification&lt;/a&gt; that amplify the forcing effects of greenhouse gases. &lt;a href=&quot;https://www.nature.com/articles/s41467-017-02771-y&quot; rel=&quot;nofollow noreferrer&quot;&gt;Deforestation&lt;/a&gt; and wild fires are another such positive feedback, they release a lot of CO2 for immediate warming effect and expose a surface ready to be eroded and not available as a carbon sink any more.&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user18411" LastEditDate="2019-12-24T11:20:42.453" LastActivityDate="2019-12-24T11:20:42.453" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18785" PostTypeId="2" ParentId="18768" CreationDate="2019-12-25T03:10:16.567" Score="1" Body="&lt;p&gt;For thick steel like a pressure vessel with 12&quot; thick walls ( not many but there are some) must leave some &quot;fossil&quot; evidence for a very ,very long time if buried. And there are many vessels with walls about 6 &quot; thick. These vessels contain a little Cr and Mo so are somewhat more corrosion resistant than carbon steels. And very tall buildings are made with composite columns have many steel bars ( roughly 3&quot; diameter bars) contained in concrete. There will be evidence of them for a very long time. And deep wells , 4 +/- individual  concentric pipes with walls of about one inch thickness encased partially in cement and buried miles into rock. etc, etc, etc.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2019-12-25T03:10:16.567" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18786" PostTypeId="1" CreationDate="2019-12-25T03:48:49.840" Score="8" ViewCount="8297" Body="&lt;p&gt;Albedo is a measure of the amount of light reflected back by an object that is incident on it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, high albedo means that a greater portion of light falling on something is reflected back. This also means a that greater amount of light goes back towards outer space which is then absorbed by the greenhouse gases present in the atmosphere. Thus high albedo contributes to global warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, if we consider low albedo, then that means a greater portion of light is absorbed thus raising the temperature or otherwise the heat content of the body. Less light is reflected back for greenhouse gases to capture. But then absorbed heat itself contributes towards global warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So as I understand, both low and high albedo contribute towards global warming. Is this understanding of mine correct?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When we do climate change engineering, what do we try to do in terms of albedo? Do we try to achieve high albedo or low albedo?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additionally I want to know about the effect of 'concrete jungles' in urban areas on global warming?&lt;/p&gt;&#xA;" OwnerUserId="18396" LastEditorUserId="2470" LastEditDate="2019-12-25T10:54:30.857" LastActivityDate="2023-04-05T16:57:01.220" Title="High albedo vs low albedo" Tags="|climate-change|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18788" PostTypeId="2" ParentId="18786" CreationDate="2019-12-25T08:04:42.657" Score="0" Body="&lt;p&gt;No, it is low albedo which contributes to global warming because ground with low albedo absorbs more of the sun's rays. High albedo reflects them back into space, and therefore has a cooling effect. When the polar caps increase in size, this can lead to an ice age if the caps reflect enough heat into space. There can be a feedback effect whereby the more the caps reflect the heat away, the more cold it gets and the more the caps increase in size, reflecting even more heat back into space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To change the earth's albedo artificially by a significant amount is an impossible task, and any attempt to do so would be prohibitively expensive as well as having the environmentalists up in arms. Whatever the solution to global warming, it isn't geo-engineering of the kind you suggest.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The concrete canyons that you mention would be much the same as natural canyons except for one thing: they consume an enormous amount of energy, much of it derived from fossil fuels, so make a contribution to global warming.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-25T08:04:42.657" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18789" PostTypeId="2" ParentId="18786" CreationDate="2019-12-25T09:22:00.807" Score="14" Body="&lt;p&gt;tl,dr: low albedo = warming (more energy absorbed); high albedo = cooling (more energy reflected).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In principle, and grossly simplifying, &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/e/e5/Diagram_showing_the_Earth%27s_energy_budget%2C_which_includes_the_greenhouse_effect_%28NASA%29.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;energy from the sun&lt;/a&gt; warms the ground and less the air. The overlying air is then warmed by the ground, leading to convection, pressure differences, and all that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, a high albedo atmosphere would &lt;a href=&quot;https://en.wikipedia.org/wiki/Albedo#Insolation_effects&quot; rel=&quot;nofollow noreferrer&quot;&gt;prevent sunlight&lt;/a&gt; from reaching the ground, having a cooling effect. Equally, a high albedo ground would reflect more sunlight, less warming the air. That's why glaciers or pole caps of ice have a feedback effect on cooling.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore, wavelengths reflected by clouds can help cooling an area by day, but also trap warmth radiating from the ground when they move over it. That depends on the situation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A low albedo atmosphere would let more sunlight pass. In conjunction with a low albedo ground it has a warming effect. Again a potential feedback when ice starts to melt and exposes more ground, leading to more warming, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An open sky will allow warming of the ground by day, but also partly cools back to space by night (continental or desert climate). Greenhouse gases are those that reflect this emitted radiation back instead of letting it escape into space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Highly populated areas can have a &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Urban_heat_island&quot; rel=&quot;nofollow noreferrer&quot;&gt;heat island effect&lt;/a&gt;&quot;, because of the low albedo of asphalt and concrete and the lack of plants and foliage to absorb sunlight for photosynthesis and &lt;a href=&quot;https://en.wikipedia.org/wiki/Evapotranspiration&quot; rel=&quot;nofollow noreferrer&quot;&gt;evaporate&lt;/a&gt; ground water and thus cool.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That (highly controversial and IMO only driven by economic interest) geoengineering thing is about raising the albedo of the stratosphere in order to reflect more sunlight before it reaches the ground. Its adverse effects on &lt;a href=&quot;https://oceanservice.noaa.gov/facts/acidification.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ocean acidification&lt;/a&gt; and damage to &lt;a href=&quot;https://www.nature.com/articles/s41598-018-29251-7&quot; rel=&quot;nofollow noreferrer&quot;&gt;marine life&lt;/a&gt; and terrestrial plants and animals (&quot;acid rain&quot;) and unresolved side effects could outweigh the potential benefits. But that is a discussion on its own, IMO.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope that helps.&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorUserId="2958" LastEditDate="2019-12-26T21:49:07.213" LastActivityDate="2019-12-26T21:49:07.213" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18790" PostTypeId="1" CreationDate="2019-12-25T14:29:34.003" Score="1" ViewCount="215" Body="&lt;p&gt;Due to IPCC the climate sensitivity of CO₂ very likely is 3.0 ± 1.5 ℃ for each doubling of the concentration of atmospheric CO₂. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Counting on earlier global warming using the Arrhenius formula [ΔT=λ·α·㏑(C/C₀)], global mean vs emissions of atmospheric CO₂, assumed mostly depending on CO₂, gives:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;1970-2018 0.9 ℃ 325ppm,408ppm: sensitivity 2.74 ℃&lt;/li&gt;&#xA;&lt;li&gt;PETM 5 ℃ 700ppm,2000ppm: sensitivity 3.30 ℃&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The Paleocene–Eocene Thermal Maximum (PETM) is associated with extreme changes in Earth's carbon cycle due to volcanism about 55 million years ago. The warm period lasted for about 200,000 years. (Wikipedia)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, there is an amount of uncertainty in the PETM figures and Earth wasn't quite the same since it was ice free etc, but these two examples support the information from IPCC with a most likely value of about 3 ℃.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The circumstances, the cause of PETM and the coincidence of the today emissions and observed warming, indicate that calculations like this is relevant. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Are there other geological events that can be used to estimate the&#xA;  climate sensitivity?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/snDIz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/snDIz.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/2wiCf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2wiCf.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;I did an error, the concentration of atmospheric CO₂ 1970 was 325 ppm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The formula I use is: Climate Sensitivity = ΔT∙㏑ 2/㏑(C/C₀)].&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I think that the Arrhenius formula is valid only for a solid sphere&#xA;  without (especially vertical) currents. Calculating the climate&#xA;  sensitivity for global land&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;a href=&quot;https://www.ncdc.noaa.gov/cag/global/time-series/globe/land/1/6/1880-2019&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncdc.noaa.gov/cag/global/time-series/globe/land/1/6/1880-2019&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;from the range of the Keeling curve gives sensitivity≈3.48 ℃.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="16809" LastEditorUserId="16809" LastEditDate="2019-12-27T10:05:47.167" LastActivityDate="2019-12-27T10:05:47.167" Title="About climate sensitivity of carbon dioxide: today compared with PETM" Tags="|geology|climate-change|co2|carbon-cycle|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="18792" PostTypeId="2" ParentId="18786" CreationDate="2019-12-25T15:47:23.073" Score="14" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;This also means a that greater amount of light goes back towards outer&#xA;  space which is then absorbed by the greenhouse gases present in the&#xA;  atmosphere.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No, it depends on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Light#Electromagnetic_spectrum_and_visible_light&quot; rel=&quot;noreferrer&quot;&gt;wavelength&lt;/a&gt;. Just like our body is transparent to &lt;a href=&quot;https://en.wikipedia.org/wiki/X-ray#Projectional_radiographs&quot; rel=&quot;noreferrer&quot;&gt;X-Rays&lt;/a&gt; but doesn't let visible light through, &lt;a href=&quot;https://en.wikipedia.org/wiki/Greenhouse_gas&quot; rel=&quot;noreferrer&quot;&gt;greenhouse gases&lt;/a&gt; let sunlight through but absorb infrared light radiated by Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.open.edu/openlearn/ocw/mod/oucontent/view.php?id=87798&amp;amp;section=_unit8.2.2&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sZpK3.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Sunlight reflected by ice or snow (=high albedo) has almost the same spectrum as sunlight and can go back to space through the atmosphere.&lt;/li&gt;&#xA;&lt;li&gt;Sunlight landing on dark material on Earth (=low albedo) will be absorbed and a portion of it will be emitted back as infrared, according to &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law&quot; rel=&quot;noreferrer&quot;&gt;Stefan–Boltzmann&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Planck%27s_law&quot; rel=&quot;noreferrer&quot;&gt;Planck&lt;/a&gt; laws. A portion of this infrared light will be &lt;a href=&quot;https://en.wikipedia.org/wiki/Greenhouse_gas#Greenhouse_gases&quot; rel=&quot;noreferrer&quot;&gt;absorbed by greenhouse gases&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="12617" LastEditorUserId="12617" LastEditDate="2019-12-25T16:13:23.157" LastActivityDate="2019-12-25T16:13:23.157" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18795" PostTypeId="1" AcceptedAnswerId="18810" CreationDate="2019-12-24T07:25:11.740" Score="5" ViewCount="263" Body="&lt;p&gt;All data I have ever encountered about the Taiga &quot;pole surrounding&quot;, vast, cold forests comprised mainly of Pinophyta trees, was about the &lt;code&gt;northern pole surrounding forests&lt;/code&gt; ranging from northern Scandinavia and northern European Russia to northern Siberia and northern Canada.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Considering woodland of areas a little bit close to the &lt;code&gt;southern pole&lt;/code&gt;, south Patagonia (extreme south of south america) reminds me a bit of the northern forests; the vegetation at and New Zealand and in Norfolk island (which might be mostly artificial in that island) a bit too, and perhaps paleoentological findings about trees in Antarctica in the past will even more resemble a &quot;Taiga&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At least by theoretical biology - could there be, or should there have been, or was a &quot;southern Taiga&quot; on earth?&lt;/p&gt;&#xA;" OwnerDisplayName="user19055" LastEditorDisplayName="user18552" LastEditDate="2019-12-28T10:35:27.407" LastActivityDate="2019-12-28T10:35:27.407" Title="At least by theoretical biology - could there be, or should there have been, or was a &quot;southern Taiga&quot; on earth?" Tags="|paleoclimatology|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18796" PostTypeId="1" CreationDate="2019-12-25T23:39:37.050" Score="1" ViewCount="102" Body="&lt;p&gt;or what type of companies should I contact to ask for the data?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This data would be produced from Seismic Vibroseis survey trucks which are mostly used to locate oil and gas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I doubt most oil and gas companies would be willing to share the data, even with researchers, so I'm stuck.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any ideas on how to obtain the digitized response data from several locations?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iRSO5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iRSO5.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18550" LastEditorUserId="18550" LastEditDate="2019-12-26T01:15:12.143" LastActivityDate="2020-08-09T17:03:10.333" Title="Where can I find broadband seismic reflection data?" Tags="|geology|seismology|seismic|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18797" PostTypeId="1" AcceptedAnswerId="18799" CreationDate="2019-12-26T00:13:34.933" Score="3" ViewCount="99" Body="&lt;p&gt;I have noticed that in many articles on minerals that I have read the abbreviation of some mineral has a numerical subscript, for example, occurs with the forsterite (Fo&lt;sub&gt;95-90&lt;/sub&gt;, Fo&lt;sub&gt;92-84&lt;/sub&gt;, Fo&lt;sub&gt;94&lt;/sub&gt;, etc.). What is the meaning of this subscript?&lt;/p&gt;&#xA;" OwnerUserId="18551" LastEditorUserId="18551" LastEditDate="2019-12-26T17:23:16.433" LastActivityDate="2019-12-26T19:09:00.323" Title="What is the meaning of the subscript in the abbreviations of some minerals?" Tags="|mineralogy|terminology|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18798" PostTypeId="2" ParentId="18780" CreationDate="2019-12-26T04:39:35.717" Score="1" Body="&lt;p&gt;Heat does not accumulate on Earth. The Earth reaches an equilibrium temperature where  outgoing thermal radiation balances incoming solar radiation, plus some smaller sources, of which our current energy production is a small part.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The geothermal heat flux from the Earth's interior is estimated to be 47 terawatts ... 0.087 watt/square metre, which represents only 0.027% of Earth's total energy budget at the surface, which is dominated by 173,000 terawatts of incoming solar radiation.&#xA;  Human production of energy is even lower, at an estimated 18 TW.   &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_energy_budget#Earth&amp;#39;s_internal_heat_and_other_small_effects&quot; rel=&quot;nofollow noreferrer&quot;&gt;wiki&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Skeptical Science says: &lt;a href=&quot;https://skepticalscience.com/waste-heat-global-warming.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Greenhouse warming 100 times greater than waste heat&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-12-26T04:39:35.717" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18799" PostTypeId="2" ParentId="18797" CreationDate="2019-12-26T08:25:00.287" Score="4" Body="&lt;p&gt;Olivine is a &lt;a href=&quot;https://en.wikipedia.org/wiki/Solid_solution&quot; rel=&quot;nofollow noreferrer&quot;&gt;solid solution&lt;/a&gt; between forsterite and fayalite, so it is generally expressed as molar percentages of these end-members, for instance Fo&lt;sub&gt;80&lt;/sub&gt;Fa&lt;sub&gt;20&lt;/sub&gt;. Often only one end-member is mentioned, as it is sufficient to infer the other (their sum is always 100 %).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is the same with plagioclase, which is a solid solution between albite and anorthite and is often expressed as &quot;Ab&lt;sub&gt;xx&lt;/sub&gt;&quot; or &quot;An&lt;sub&gt;xx&lt;/sub&gt;&quot;, where xx is the molar percentage of considered end-member.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: As for the range, e.g. 95-90, I'd say they analyzed several olivine grains in the same sample, and the range represents the variability of compositions they found. It could also be the analytical error on a single composition, but I doubt it would be that large, although it could be in some old papers when the precision of chemical analyses was not as good as today.  &lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2019-12-26T19:09:00.323" LastActivityDate="2019-12-26T19:09:00.323" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18800" PostTypeId="1" AcceptedAnswerId="18818" CreationDate="2019-12-26T12:20:34.807" Score="1" ViewCount="59" Body="&lt;p&gt;I would like to write my thesis on modelling extreme rainfall events in urban areas coupling a 2D surface model with an 1D sewer channel model. I have access to a good software which models hydrodynamically and offers me 3 different modelling approaches. My basic idea was to apply all three approaches and compare them and see what happens but my prof. is not convinced yet. He is happy with the model but he wants me to formulate a clear research question and ideally a hypothesis. Further, I can apply the model but I have no data to verify the results. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm stuck here, I don't know how to come up with a good research question and hypothesis. Maybe you can give me some ideas of what I could do?&lt;/p&gt;&#xA;" OwnerUserId="18553" LastEditorUserId="18081" LastEditDate="2019-12-27T06:39:27.347" LastActivityDate="2020-01-28T08:01:50.203" Title="research question for modelling extreme rainfall event with coupled 2D surface and 1D sewersystem model" Tags="|hydrology|models|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18801" PostTypeId="1" AcceptedAnswerId="18812" CreationDate="2019-12-26T13:37:43.017" Score="1" ViewCount="957" Body="&lt;p&gt;In the description of a Software it says that it computes the net rainfall, runoff formation and runoffconcentration on a surface hydrologically. With an extra module, the runoff formation can also be computed hydrodynamically. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the difference? How does both work, roughly speaking? &lt;/p&gt;&#xA;" OwnerUserId="18553" LastActivityDate="2019-12-28T12:36:22.430" Title="hydrologic vs. hydrodynamic modelling of surface runoff" Tags="|hydrology|models|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18803" PostTypeId="2" ParentId="18780" CreationDate="2019-12-26T16:50:17.917" Score="0" Body="&lt;p&gt;At present, only 51% of energy is reaching the earth surface (including oceans) in any given normal year with cloud cover as normal (excluding a peak sunspot cycle year which would have significantly reduced cloud cover across the earth). All of that energy makes its way out eventually as per a heat budget balance and so with reduced CO2 emissions of 410 ppms cut in half or greater to account for human contribution, one could address your question adequately from the GHG Effect with a simple &gt; NO ISSUE for increased use of energy as the heat by-product would be 'lesser' or less potent as per the thermodynamic laws. Your question was: (Could our energy consumption increase indefinitely without affecting the ability of Earth to support our current ecosystem; or will be ultimately have to limit our energy use?) To answer the question succinctly, NO, I do not equate greater effects to ecosystems or affecting our ecosystems as a result of rising energy solar demand with a subsequent reduction of GHG by from human sources. Also to add to the answer, if CO2 emissions greatly and there was less fallout of CO2 in rainfall into our oceans, the ability for plankton to greatly increase would improve tremendously and therefore add to the balance effect of respiring greater amounts of oxygen into the atmosphere providing a better situation for animals species on land and in the water. For me, carbon reduction in the atmosphere and in the water would allow for greater photosynthesis and therefore, greater cooling in both systems, but especially in aquatic system in the Epipelagic zone where light would interact with microscopic plankton that generate huge amounts of 'cooling' oxygen for the earth systems. Here is a supportive article: &lt;a href=&quot;https://www.sciencedaily.com/releases/2007/11/071117121016.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedaily.com/releases/2007/11/071117121016.htm&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18476" LastEditorUserId="18476" LastEditDate="2019-12-27T16:17:13.693" LastActivityDate="2019-12-27T16:17:13.693" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18804" PostTypeId="2" ParentId="18795" CreationDate="2019-12-26T22:10:15.590" Score="-2" Body="&lt;p&gt;There was a sort of southern taiga on the northern fringes of Antarctica about 40 million years ago in the early tertiary, but this was probably killed off by the increasingly cold weather some ten million years later. The taiga as we know it today is in the northern hemisphere and is composed mainly of conifers (taiga is a Russian word), but you wouldn't expect a taiga in the antipodes to be of the same species as in the northern hemisphere, or for there to be a Russian word for it. There were no contemporary Russians.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The southern taiga was composed of nothofagus trees, a hardy broadleaf also known as southern beech, and there is a relict population remaining in a ring extending from extreme S.America, S.Australia, and New Zealand. In the late cretaceous these continents were linked to Antarctica, but continental drift has since separated them. Fossil nothofagus wood, seeds and pollen have been found in Antarctica.  There is also a relict population of nothofagus in montane New Guinea, but it is not known when it arrived there. As Fred suggests, the southern taiga may also have included Wollemia pine, but this has yet to be proved.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-26T22:10:15.590" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18805" PostTypeId="1" CreationDate="2019-12-27T15:20:25.240" Score="1" ViewCount="64" Body="&lt;p&gt;As such the fuel for earth’s Carbon cycle. &#xA;Wouldn’t photons be the alleged “electromagnetic” mode of energy transfer into earth? &#xA;Providing energy for the endothermic photosynthetic processes and heat for all and mass exposed to this energy modality. Mass can be gas, liquid or solid. In All instances converting thermic or light energy into increased molecular motion. &#xA;What would be the vector for energy to be transferred out of earth atmosphere into the empty firmament. &lt;/p&gt;&#xA;" OwnerUserId="18559" LastEditorUserId="18559" LastEditDate="2019-12-27T19:52:57.630" LastActivityDate="2019-12-27T19:52:57.630" Title="Aren’t photons the vector for energy input to earth?" Tags="|earth-system|" AnswerCount="1" CommentCount="8" ClosedDate="2019-12-27T17:23:28.517" ContentLicense="CC BY-SA 4.0" />
  <row Id="18806" PostTypeId="2" ParentId="18805" CreationDate="2019-12-27T16:09:17.250" Score="0" Body="&lt;p&gt;Photons do not emit energy but rather, carry stored kinetic energy that has the potential to give or TAKE AWAY heat so, to answer your question, they ARE an energy vector but would think they are not the fuel for the Carbon Cycle since they get scattered by particles and water vapour....which leads me to think they are part of the cocktail, but not the fuel in itself. Here is an excellent visual and summarized source for interactions of radiation with the atmosphere &gt; &lt;a href=&quot;https://www.nrcan.gc.ca/maps-tools-publications/satellite-imagery-air-photos/remote-sensing-tutorials/introduction/interactions-atmosphere/14635&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nrcan.gc.ca/maps-tools-publications/satellite-imagery-air-photos/remote-sensing-tutorials/introduction/interactions-atmosphere/14635&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I believe you have asked an excellent question and look forward to reading the subsequent responses.&lt;/p&gt;&#xA;" OwnerUserId="18476" LastActivityDate="2019-12-27T16:09:17.250" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18807" PostTypeId="2" ParentId="18266" CreationDate="2019-12-27T18:31:51.980" Score="0" Body="&lt;p&gt;You can use the formula ΔT=λ·α·㏑(C/C₀), (natural logarithm) where C is the later concentration of CO₂ and C₀ the earlier concentration. λ and α is constants. This formula is valid for a solid sphere but since 70 % of the surface of Earth is water, which warms up much deeper and accumulate about 90 % of the accumulated energy, it isn't totally clear how to use the formula correct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One way could be to use the formula on global land temperatures and transform to global temperature for sea and land afterwards, somehow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Otherwise, the calculations won't be exact.&lt;/p&gt;&#xA;" OwnerUserId="16809" LastEditorUserId="16809" LastEditDate="2019-12-27T19:57:42.257" LastActivityDate="2019-12-27T19:57:42.257" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18808" PostTypeId="1" CreationDate="2019-12-27T20:40:13.940" Score="1" ViewCount="263" Body="&lt;p&gt;It is reported in the media that currently in Australia there are dozens of wildfires caused by lightning strikes. I am familiar with the mechanism of ordinary British lightning involving cumulonimbus and moisture, but I don't understand the Australian mechanism where hot,bone dry conditions cause lightning strikes on a massive scale, apparently from cloudless or near cloudless skies. The role of high temperatures and near cloudless skies obviously makes vegetation highly inflammable, but solar radiation hot enough to heat it to ignition temperature would kill everyone in Australia, so contrary to what some people appear to believe it can't be that. Perhaps someone can offer an explanation.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorDisplayName="user1066" LastEditDate="2019-12-28T06:19:58.800" LastActivityDate="2019-12-30T10:48:07.763" Title="Large Scale lightning Strikes from Cloudless or Near Coudless Skies. How Does it Work?" Tags="|meteorology|lightning|drought|wildfire|" AnswerCount="1" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="18809" PostTypeId="2" ParentId="18808" CreationDate="2019-12-28T02:07:00.423" Score="6" Body="&lt;p&gt;&lt;strong&gt;Revised answer&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;TL;DR&lt;/strong&gt; After having just heard from two experts who actually work in this field(firestorms and dry lightning) in Australia I believe the lightning seen is what is known as &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Dry_thunderstorm&quot; rel=&quot;nofollow noreferrer&quot;&gt;dry lightning&lt;/a&gt;&quot; comes from isolated thunderstorms and sometimes storms associated with minor troughs and fronts that come through Australia and also originating from a &lt;a href=&quot;https://en.wikipedia.org/wiki/Cumulonimbus_flammagenitus&quot; rel=&quot;nofollow noreferrer&quot;&gt;pyrocumulonimbus&lt;/a&gt; cloud. So @David Hammen and @jamesql are correct in their observations that the large scale dry lightning is indeed originating from isolated thunderstorms as well as storms associated with minor troughs and fronts. This dry lightning the experts confirm  is associated with little rain. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition &lt;strong&gt;there have also been several  dry lightning strikes from pyrocumulonimbus clouds&lt;/strong&gt;. As an example for today over 20 dry lightning strikes have been recorded originating from pyrocumulonimbus clouds. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The major driver for the current drought like conditions over Australia is the large anomalous positive Indian Ocean Dipole (&lt;a href=&quot;http://www.bom.gov.au/climate/iod/&quot; rel=&quot;nofollow noreferrer&quot;&gt;positive IOD&lt;/a&gt;) that has persisted well into boreal autumn/astral spring. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What the experts mention is that while the dry hot conditions are sporadic (2-4 days) they are persisting over over many weeks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following articles written by two researchers &lt;a href=&quot;https://theconversation.com/firestorms-and-flaming-tornadoes-how-bushfires-create-their-own-ferocious-weather-systems-126832&quot; rel=&quot;nofollow noreferrer&quot;&gt; Firestorms and flaming tornadoes: how bushfires create their own ferocious weather systems&#xA;&lt;/a&gt; and &lt;a href=&quot;https://theconversation.com/firestorms-the-bushfire-thunderstorm-hybrids-we-urgently-need-to-understand-68426&quot; rel=&quot;nofollow noreferrer&quot;&gt;Firestorms: the bushfire/thunderstorm hybrids we urgently need to understand&lt;/a&gt; provide information on the dynamics behind firestorms and the formation of pyrocumulus clouds and the associated dry lightning. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Following is a  summary of those articles and the conditions that lead to dry lightning from pyrocumulonimbus clouds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not all bushfires lead to firestorms. If a bushfire has sufficient area the upward movement of air causes the fire to interact with the atmosphere above it and form what is known as a pyrocloud. If in addition  there is an atmospheric instability then this process leads to the formation of a pyrocumulonimbus cloud . Normally in meteorology we are taught of heat radiating from the ground but in this case the upward movement of air is due to the heat emanating from the fire. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Again from mesoscale meteorology one hears the word &quot;downdrafts&quot;. Similarly in this context the appropriate word is &quot;downbursts&quot; and these are vertical drafts of air that hit the ground and move about in all directions. The unsettled conditions cause embers to carry over large distances. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These firestorms produce dry lightning that potentially can spark new fires that may end up creating a larger flaming zone. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2019-12-30T10:48:07.763" LastActivityDate="2019-12-30T10:48:07.763" CommentCount="18" ContentLicense="CC BY-SA 4.0" />
  <row Id="18810" PostTypeId="2" ParentId="18795" CreationDate="2019-12-28T10:31:29.417" Score="7" Body="&lt;p&gt;I'll define a boreal forest as a place that&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Has trees, i.e., long-lived woody plants that are capable of growing at least ten meters tall and that grow both upward by extending new branches and outward by widening of the trunk. Amongst other things, this rules out times before ~380 million years ago, which was when the first trees formed.&lt;/li&gt;&#xA;&lt;li&gt;Has sufficient trees so as to constitute a forest, which I'll define as a largish area where trees grow sufficiently dense so as to form a more or less closed canopy. This distinguishes forests from areas with only  a few trees such as savannas and krummholz.&lt;/li&gt;&#xA;&lt;li&gt;Has very harsh winters, with at least one month where the average temperature is well below freezing, and temperatures of -40° C are not rare. This distinguishes boreal forests from cold oceanic forests such as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Magellanic_subpolar_forests&quot; rel=&quot;noreferrer&quot;&gt;Magellanic subpolar forests&lt;/a&gt; in southern Chile and Argentina.&lt;/li&gt;&#xA;&lt;li&gt;Has mild summers, with only a few months where the average temperature exceeds 10° C. This distinguishes boreal forests from hemiboreal and temperate forests. Note that some scientists do not make this distinction, classifying Köppen climate zone Dfb as boreal.&lt;/li&gt;&#xA;&lt;li&gt;Is extensive. This distinguishes large boreal forests from high altitude subalpine forests that would locally pass the above tests. Subalpine forests can occur at any latitude, including &lt;a href=&quot;https://en.wikipedia.org/wiki/Snowy_Mountains&quot; rel=&quot;noreferrer&quot;&gt;Australia's Snow Mountains&lt;/a&gt;, New Zealand's &lt;a href=&quot;https://en.wikipedia.org/wiki/Southern_Alps&quot; rel=&quot;noreferrer&quot;&gt;Southern Alps&lt;/a&gt;, and parts of the Andes.  This is not a clear-cut boundary. As a climate cools, subalpine forests may spread to the valleys between mountains and then spread out beyond the mountains. At some point, such montane forests becomes boreal forests.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The need for very harsh winters coupled with the need for extensiveness means that boreal forests did not exist between the start of the Triassic ~252 million years ago to the end of the Eocene ~34 million years ago. The Earth was in its greenhouse phase during that long stretch of time, with balmy temperatures year round even at the poles. A boreal forest can only exist when the Earth is in its icehouse phase. This includes the last 34 million years, and also the period between 340 to 250, the late Paleozoic glaciation. Unlike the current ice age, the Earth in the late Paleozoic had land (Gondwana) surrounding the South Pole.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question then is whether either of those intervals (the last ~34 million years, and the late Paleozoic glaciation) have supported a southern boreal forest. Per &lt;em&gt;Rees-Owens et al.&lt;/em&gt;, the answer is a possible yes to the more recent interval. Forests existed on Antarctica until as recently as 2.5 million years ago. Whether these were Köppen climate zone Cfc (subpolar) or Dfc (continental boreal) is very hard to say. If one relaxes the requirement for cold winters a bit, then those recent forests almost certainly were boreal.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Per &lt;em&gt;Horton, et al.&lt;/em&gt;, and also per the authors of several related papers, the answer is an unequivocal yes to the more ancient interval. Moreover, the boreal forest of that ancient time would have been very much like the boreal forest of present time: One of the largest ecozones on the planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/ngeo922&quot; rel=&quot;noreferrer&quot;&gt;Horton, D.E., Poulsen, C.J. and Pollard, D., 2010. Influence of high-latitude vegetation feedbacks on late Palaeozoic glacial cycles. Nature Geoscience, 3(8), p.572.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/nature11300&quot; rel=&quot;noreferrer&quot;&gt;Pross, J., Contreras, L., Bijl, P.K., Greenwood, D.R., Bohaty, S.M., Schouten, S., Bendle, J.A., Röhl, U., Tauxe, L., Raine, J.I. and Huck, C.E., 2012. Persistent near-tropical warmth on the Antarctic continent during the early Eocene epoch. &lt;em&gt;Nature&lt;/em&gt;, 488(7409), p.73.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S014663801730219X&quot; rel=&quot;noreferrer&quot;&gt;Rees-Owen, R.L., Gill, F.L., Newton, R.J., Ivanović, R.F., Francis, J.E., Riding, J.B., Vane, C.H. and dos Santos, R.A.L., 2018. The last forests on Antarctica: Reconstructing flora and temperature from the Neogene Sirius Group, Transantarctic Mountains. &lt;em&gt;Organic Geochemistry&lt;/em&gt;, 118, pp.4-14.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2019-12-28T10:31:29.417" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18812" PostTypeId="2" ParentId="18801" CreationDate="2019-12-28T12:36:22.430" Score="4" Body="&lt;p&gt;The word &quot;hydrological&quot; is meant to indicate that the model only includes a sort of bulk description of the water: where it is, how much is there, and where it flows. It generally only includes length and time scales of interest to the system in question. So, for ground water models, this may be tens of meters and longer in horizontal direction, and hours and longer in time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, &quot;hydrodynamic&quot; is generally understood to resolve the governing equations for water flow, i.e., the Navier-Stokes equations (possibly posed in a porous medium). This must then deal with the length and time scales of eddies, which are substantially smaller and shorter than the ones above, and consequently requires a lot more computational power.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2019-12-28T12:36:22.430" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18813" PostTypeId="2" ParentId="18777" CreationDate="2019-12-28T12:40:51.047" Score="1" Body="&lt;p&gt;Why would you limit yourself? You could just go to a regular university and enroll in the geology degree program. In some countries (like Germany) you would then only take courses necessary to become a geologist (including the math and physics you need to understand for it). In some other countries (e.g, the United States) you'd have to take other courses for &quot;breadth requirements&quot; as well, but most of your courses would still be in geology. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fact that a regular university &lt;em&gt;also&lt;/em&gt; offers courses in other areas doesn't really matter that much, or does it?&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2019-12-28T12:40:51.047" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18814" PostTypeId="2" ParentId="18774" CreationDate="2019-12-28T16:51:52.757" Score="2" Body="&lt;p&gt;Refer to the &lt;a href=&quot;http://www.stratigraphy.org/ICSchart/ChronostratChart2018-07.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;stratigraphic chart&lt;/a&gt; for timeline and stratigraphic units. And i tried to be as up to date as possible in the limited time. Which is also the reason why i omitted some details in favour of an overview.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is assumed that during the early and middle Archaen only very &lt;a href=&quot;https://www.pnas.org/content/116/14/6647&quot; rel=&quot;nofollow noreferrer&quot;&gt;sporadic oxygen&lt;/a&gt; production took place. This changes towards the end of the Archean, when a &lt;a href=&quot;https://advances.sciencemag.org/content/4/1/e1701835.full&quot; rel=&quot;nofollow noreferrer&quot;&gt;flow of oxygen&lt;/a&gt; from shallow ocean parts to the atmosphere began.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://advances.sciencemag.org/content/2/5/e1600134&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; suggests that the following &quot;great oxygenation event&quot; (goe), at the early Proterozoic 2.33Gy just took up to 10 million years. During the goe, atmopsheric oxygen increased to 1 or 2 percent, the exact percentage seems unclear. But it seems that in &lt;a href=&quot;https://www.nature.com/articles/s41561-019-0309-7&quot; rel=&quot;nofollow noreferrer&quot;&gt;some places&lt;/a&gt;, a fully oxygenated ocean existed slightly before the goe at the end of the Archean, at ~2.5Gy. These waters would have been able to produce excess oxygen for the atmosphere in a small or regional scale slightly earlier.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Atmospheric O2 &lt;a href=&quot;https://www.nature.com/articles/ncomms14379&quot; rel=&quot;nofollow noreferrer&quot;&gt;stays low&lt;/a&gt; during the Proterozoic, probably because it is used up in weathering processes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the beginning of the Cambrian, O2 was still low (~5%). &lt;a href=&quot;https://www.nature.com/articles/s41467-018-06383-y&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; describes the development thorugh the Phanerozoic by combining data from modelling and proxies. See &lt;a href=&quot;https://www.nature.com/articles/s41467-018-06383-y/figures/3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Figure 3&lt;/a&gt; (there's your plot;-). It shows that not before the end of the Ordovician atmospheric O2 rises to above 10%, topping off at the end of the Permian at ~32%.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://scrippso2.ucsd.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;These days&lt;/a&gt;, oceanic as well as &lt;a href=&quot;https://science.sciencemag.org/content/353/6306/1427&quot; rel=&quot;nofollow noreferrer&quot;&gt;atmopsheric&lt;/a&gt; O2 levels &lt;a href=&quot;https://science.sciencemag.org/content/359/6371/eaam7240&quot; rel=&quot;nofollow noreferrer&quot;&gt;are falling&lt;/a&gt; and &lt;a href=&quot;https://www.nature.com/articles/nature21399&quot; rel=&quot;nofollow noreferrer&quot;&gt;will continue&lt;/a&gt; to do so because of fossil fuel combustion.&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastEditorDisplayName="user18411" LastEditDate="2019-12-29T08:57:35.673" LastActivityDate="2019-12-29T08:57:35.673" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18815" PostTypeId="1" CreationDate="2019-12-28T23:39:46.520" Score="1" ViewCount="155" Body="&lt;p&gt;I made a question in WolrdBuilding as I was directed to.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There a user said that with a perfect ball all water would pool to the equator because of centripetal force.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What I do not understand is how would the earth being perfect ball have all the water pooled to the equator when it does not do so now?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A perfect ball would have less difference between the radius close to the poles and the radius around the equator than what the current earth has.&lt;/p&gt;&#xA;" OwnerUserId="17030" LastEditorUserId="6467" LastEditDate="2020-02-09T17:59:24.527" LastActivityDate="2020-02-12T00:06:27.977" Title="Centripetal Force Perfect Ball and Water" Tags="|geology|geophysics|planetary-science|geodesy|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18816" PostTypeId="2" ParentId="18509" CreationDate="2019-12-29T03:16:28.017" Score="0" Body="&lt;p&gt;Here is the information that has the tool that you can do this &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://cds.nccs.nasa.gov/nex-gddp/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://cds.nccs.nasa.gov/nex-gddp/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have never use this but ran google it and found this..&lt;/p&gt;&#xA;" OwnerUserId="5771" LastActivityDate="2019-12-29T03:16:28.017" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18818" PostTypeId="2" ParentId="18800" CreationDate="2019-12-29T07:48:49.967" Score="1" Body="&lt;p&gt;It sounds as though you have ideas on the tools you'd like to use, but not on an actual question that you want to use them to answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You probably need to either come up with such a question, or focus instead on methodology - in studying the tools and the effectiveness of using them in a given scenario.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For nearly any modelling project, its viability will be affected by whether data are available to validate the model. If no appropriate data are available for the area you're looking at, you probably don't have a project (because what use is a model if you have no idea whether it's right?).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bear in mind that these comments are all generalisations based on very limited information. The best advice is still &quot;talk to your advisor&quot;.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2019-12-29T07:48:49.967" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18820" PostTypeId="2" ParentId="18815" CreationDate="2019-12-29T09:18:30.603" Score="3" Body="&lt;p&gt;If the Earth were a perfect ball, which it is not, and had a perfectly smooth and even surface with no basins or irregularities, water would tend to move toward the equator, where it would form a bulge. Meanwhile, gravity would be pulling on this bulge and trying to drag it down, thus preventing it getting any higher and stopping the flow of water into it. To increase the height of the bulge and allow more water to flow to the equator, the Earth would have to spin faster. There is no way that I know of to make the Earth spin faster, on the contrary, it is very gradually slowing down. The oceans do tend to bulge at the equator, as does the more solid part of the Earth, forming the well known equatorial bulge. As you didn't mention any moon, apart from the fact that it slows the Earth's rotation I am ignoring the effect of the moon, as that would complicate matters.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2019-12-29T10:36:34.387" LastActivityDate="2019-12-29T10:36:34.387" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18821" PostTypeId="1" AcceptedAnswerId="18825" CreationDate="2019-12-29T10:29:19.517" Score="1" ViewCount="93" Body="&lt;p&gt;I am trying to study climate change and lately, I am realizing that oil companies were/are drilling for oils at Alaska, Arctic, Antarctica.&#xA;Where oil (which oil company drills) is used maximum for?&#xA;I am looking for some exhaustive list.&#xA;I am reading some sources but they are mostly vague and too shallow like for gas in vehicles , electricity etc.&#xA;Any answer which provides exhaustive list or exhaustive material which I can study (even books are cool with me) are appreciated.&lt;/p&gt;&#xA;" OwnerUserId="18564" LastActivityDate="2019-12-29T19:20:15.203" Title="Where oil is used for" Tags="|climate-change|climate|oil-reserves|" AnswerCount="1" CommentCount="6" ClosedDate="2019-12-30T15:40:01.030" ContentLicense="CC BY-SA 4.0" />
  <row Id="18823" PostTypeId="2" ParentId="18815" CreationDate="2019-12-29T16:50:02.537" Score="5" Body="&lt;p&gt;In short, weird things happen when you combine things that don't combine in nature:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the Earth as a perfect sphere&lt;/li&gt;&#xA;&lt;li&gt;the Earth spinning on an axis&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Einstein's &lt;a href=&quot;https://en.wikipedia.org/wiki/Equivalence_principle#The_Einstein_equivalence_principle&quot; rel=&quot;nofollow noreferrer&quot;&gt;equivalence principle&lt;/a&gt; tells us that accelerations are all the same, no matter what's causing them. So you just add the acceleration vectors up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The (real) Earth has an equatorial bulge because a stable surface can only exist where those vectors sum to zero:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;gravity&lt;/li&gt;&#xA;&lt;li&gt;residual (&quot;centrifugal&quot;) acceleration from the Earth's rotation&lt;/li&gt;&#xA;&lt;li&gt;the ground holding you up&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;This is called an &lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Equipotential&quot; rel=&quot;nofollow noreferrer&quot;&gt;equipotential surface&lt;/a&gt;&lt;/em&gt; and because of the centrifugal acceleration, on a spinning Earth this surface is an ellipsoid (well, mostly; there are small adjustments due to mass distribution). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The constraint of having a perfect sphere means that the materials making up &lt;s&gt;the Earth&lt;/s&gt; your fictional planet are strong enough to keep it from ballooning out and filling an equipotential surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if you make your fictional planet a perfect sphere, what you're really doing is changing where #3 happens but leaving #1 and #2 the same.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, you're creating a 26 km deep valley encircling the globe. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Water runs downhill.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So eventually, all of the water will flow down into the giant equatorial valley...&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2020-02-12T00:06:27.977" LastActivityDate="2020-02-12T00:06:27.977" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18824" PostTypeId="1" AcceptedAnswerId="18860" CreationDate="2019-12-29T18:11:08.690" Score="3" ViewCount="109" Body="&lt;p&gt;I'm a PhD student studying the (current) climate of the Earth. I'm also quite interested in the history of planet Earth, although I have little academic background in that area. Is there a good textbook on the history of the planet, ideally one that has some focus on the climate?&lt;/p&gt;&#xA;" OwnerUserId="18567" LastEditorUserId="6535" LastEditDate="2019-12-29T19:44:11.410" LastActivityDate="2020-02-02T10:01:35.183" Title="Earth History Book" Tags="|earth-history|paleoclimatology|reference-request|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18825" PostTypeId="2" ParentId="18821" CreationDate="2019-12-29T19:20:15.203" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pZYu4.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pZYu4.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://oilprice.com/Energy/Crude-Oil/Peak-Oil-Myth-Or-Coming-Reality.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;OilPrice&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Petrochemicals are used to make numerous products.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/hDYQS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hDYQS.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://energi.media/news/petrochemical-products-in-everyday-life/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2019-12-29T19:20:15.203" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18827" PostTypeId="1" CreationDate="2019-12-30T02:09:08.233" Score="1" ViewCount="470" Body="&lt;p&gt;When a tsunami gets into the coast we are approximately at 0 meters above average sea level (AASL). And then it starts ascending in the uphill land... 1m AASL... 2,3... 5,10 m AASL etc.&lt;/p&gt;&#xA;&lt;p&gt;That is exactly my question. What is the highest altitude a tsunami has ever reached? Maybe it always remains in low level, like 10 or 15 meters above average sea level or there are records about 40-50 meters? Is there a confirmed record? Records after renaissance or ancient Greeks, Egyptians, Chinese etc could be considered reliable?&lt;/p&gt;&#xA;&lt;p&gt;PS: I am not talking about its height while it is in sea or when it crashes the coast. I am talking about the highest land altitude that a tsunami has ever reached much later after its crashing in coast.&lt;/p&gt;&#xA;&lt;p&gt;PS2: I understand that my question is not clear and it has vagueness, so I will try to clarify it. Every point in the surface of Earth has coordinates (with respect to North and East). And each unique point has an altitude. Two examples: a) The point with coordinates 27.9881° N, 86.9250° E has altitude 8848 meters. It is Everest's summit. b) The point with coordinates 36°34′N 21°8′E has altitude - 5267 m. It is Calypso Deep, the deepest point of Mediterranean.&lt;/p&gt;&#xA;&lt;p&gt;So, my question, I look for a specific point on the Earth with the maximum altitude A and coordinates B North and C East in which the sea water has ever reached (let's focus on relatively recent years after renaissance). As I understand this can happen only by phenomena like big waves or tsunamis. There is no something else. So where is this point and what is its altitude? In that case, we don't care about the height or the momentum of the wave. Also the accuracy is not so important... Just an idea &amp;quot;when a tsunami climbed a mountain&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;About Lituya Bay in Alaska... There is a mountain there: Fairweather with altitude 4671 m... So the tsunami in 1958 ascended 524 m in this mountain? Why I think it didn't even pass 100 m altitude? The height of a wave is completely different and independent with the highest altitude it finally reaches.&lt;/p&gt;&#xA;" OwnerUserId="18570" LastEditorUserId="2470" LastEditDate="2022-10-19T00:30:13.247" LastActivityDate="2022-10-19T00:30:13.247" Title="Highest land altitude a tsunami has ever reached (record)" Tags="|waves|tsunami|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18828" PostTypeId="2" ParentId="18827" CreationDate="2019-12-30T05:39:27.033" Score="2" Body="&lt;p&gt;The worlds highest &lt;em&gt;recorded&lt;/em&gt; tsunami occurred during a landslide triggered by an earthquake in 1958 in Lituya Bay, Alaska. The landslide sent the water 524 meters high the other side of the valley and left its contours in the vegetation. According to whitnesses, it lifted a glacier tip above the surrounding mountain tops.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://geology.com/records/biggest-tsunami.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://geology.com/records/biggest-tsunami.shtml&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthquake.alaska.edu/60-years-ago-1958-earthquake-and-lituya-bay-megatsunami&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earthquake.alaska.edu/60-years-ago-1958-earthquake-and-lituya-bay-megatsunami&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think this was the highest run-up on records (let's see if i get topped). But there probably occurred higher ones in earth's history. Candidates are asteroid impacts (e.g. Chicxulub) or &lt;a href=&quot;https://www.nature.com/articles/ncomms15246&quot; rel=&quot;nofollow noreferrer&quot;&gt;flank collapses&lt;/a&gt; on volcanic islands.&lt;/p&gt;&#xA;" OwnerDisplayName="user18411" LastActivityDate="2019-12-30T05:39:27.033" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18830" PostTypeId="2" ParentId="8806" CreationDate="2019-12-30T11:05:07.590" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Cimarron_River_(Arkansas_River_tributary)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cimarron River&lt;/a&gt;, a salt river, extends 698 miles (1,123 km)&#xA;  across New Mexico, Oklahoma, Colorado, and Kansas. The headwaters flow&#xA;  from Johnson Mesa west of Folsom in northeastern New Mexico. Much of&#xA;  the river's length lies in Oklahoma, where it either borders or passes&#xA;  through eleven counties. There are no major cities along its route.&#xA;  The river enters the Oklahoma Panhandle near Kenton, Oklahoma, crosses&#xA;  the southeastern corner of Colorado into Kansas, reenters the Oklahoma&#xA;  Panhandle, reenters Kansas, and finally returns to Oklahoma where it&#xA;  joins the Arkansas River at Keystone Reservoir west of Tulsa,&#xA;  Oklahoma, its only impoundment. The Cimarron drains a basin that&#xA;  encompasses about 18,927 square miles (49,020 km2).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Edit:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Cimarron's water quality is rated as poor because the river flows through natural mineral deposits, salt plains, and saline springs, where it dissolves large amounts of minerals.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="18572" LastEditorUserId="2470" LastEditDate="2019-12-30T17:10:11.160" LastActivityDate="2019-12-30T17:10:11.160" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18832" PostTypeId="1" CreationDate="2019-12-30T20:20:37.293" Score="2" ViewCount="87" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Global_cooling&quot; rel=&quot;nofollow noreferrer&quot;&gt;global cooling&lt;/a&gt; hypothesis of the 1970s included the theory that aerosols lead to &lt;a href=&quot;https://en.wikipedia.org/wiki/Global_dimming&quot; rel=&quot;nofollow noreferrer&quot;&gt;global dimming&lt;/a&gt;. That is, that pollutants reduces the amount that the Sun warms the Earth, causing the Earth's surface to cool.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My understanding is that the theory itself was sound, though in the end the effects of greenhouse gases dominated the trend. Hence, climate change takes the form of global warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Setting aside the obvious biological effects from aerosol pollution (e.g. less plant growth), how much of that pollution would be physically required to offset global warming? Are the effects even in the same ballpark?&lt;/p&gt;&#xA;" OwnerUserId="18576" LastEditorUserId="18576" LastEditDate="2019-12-30T20:26:12.247" LastActivityDate="2019-12-30T22:19:07.460" Title="How much pollution would it take to stop global warming?" Tags="|climate-change|pollution|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18833" PostTypeId="1" CreationDate="2019-12-30T20:38:17.833" Score="1" ViewCount="75" Body="&lt;p&gt;My questions are: is there a significant, joint, worldwide, inter-disciplinary, scientific effort to study (brainstorm) possible solutions to climate-change?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If it does exist, in whatever form, does it really include many if not all disciplines, beyond natural sciences and engineering? Additionally, do economists regularly talk to experts in game-theory, sociologists to mathematicians, chemists to ... and everyone else?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems to me that today any such work is quite fragmented, left to smaller groups, at universities for example. And it is clearly not found under the umbrella of the IPCC, the UNFCCC, or the COPs (unless I am missing something - which could be your answer). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One might think that such an effort would require significant funding, and that the lack of such is to be seen as a political decision. But neither am I interested in the underlying politics, nor in more COP like conferences. This question is really and only about: where is 'finding solutions' (brainstorming) done, who does it, where, exactly how? How big is it? Is the scale adequate to the scale of the problem  (think Apollo!). If the answer is 'no', I would also like to get some feedback on 'why not'? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This question is related to my earlier question on the same subject, which appeared to be only borderline on-topic to this forum. &lt;/p&gt;&#xA;" OwnerUserId="18524" LastEditorUserId="2470" LastEditDate="2019-12-31T05:34:43.430" LastActivityDate="2019-12-31T05:34:43.430" Title="Climate Change - finding solutions" Tags="|climate-change|" AnswerCount="0" CommentCount="8" ClosedDate="2020-01-02T12:39:10.397" ContentLicense="CC BY-SA 4.0" />
  <row Id="18834" PostTypeId="2" ParentId="18832" CreationDate="2019-12-30T21:17:59.660" Score="0" Body="&lt;p&gt;How much? A lot more than you could afford, and probably more than the government could afford. The most effective climate dimming agent is said to be sulphur dioxide,sprayed into the upper atmosphere, where it reflects the sun's rays back into space. Smoke and dust particles also have a dimming effect if there is enough of them. We get both of these effects when there is a massive volcanic eruption like Pinatubo in the 1980s, or better still, Tambora in 1815.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The trouble is that the effect doesn't last very long. Pinatubo had a very slight effect for about a year, Tambora (the most massive eruption in historical times) a more dramatic effect for several years, but global warming persists for centuries.  The dust eventually falls to earth, the SO2 becomes acid rain and wreaks havoc with buildings and non-resistant structures on the ground. If you were an eccentric billionaire and wanted to do it, you wouldn't be allowed to. It wouldn't achieve the effect you wanted in any case, but if you went ahead regardless and the expense of the project didn't bankrupt you, the law suits by people damaged by your pollution would.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you say, pollution inhibits plant growth, which is the opposite of what we need because plant growth reduces atmospheric CO2.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-30T21:17:59.660" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18835" PostTypeId="1" AcceptedAnswerId="18842" CreationDate="2019-12-30T22:13:41.620" Score="1" ViewCount="149" Body="&lt;p&gt;Imagine that a person's individual carbon emissions were logged and accounted for in a ledger over an entire lifetime.  If that person could perform certain actions to subtract from their carbon emissions in this ledger, what might these actions be?  Via such actions, would it be possible to end up with a carbon negative final total at death, assuming that person continues to indulge in all the activities that currently contribute to global climate change (e.g. eating red meat, using fossil fuels)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, is there a rough number of trees that would need to be planted to 'pay' for these emissions in the ledger over an entire lifetime, and then some (assuming average life expectancy of person living in 1st world country)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: I understand such a question is necessarily vague due to the sheer number of variables at play.  As such, I wouldn't be looking at exact numbers, rather some kind of scale.  That is, I would be interested to hear whether something needs to be done hundred's, thousands, or tens of thousands of times, etc.  In regards to the individual, let's assume a 'typical' person who lives in Australia (from the &lt;a href=&quot;https://www.abs.gov.au/ausstats/abs%40.nsf/mediareleasesbyCatalogue/5E54C95D3D5020C6CA2580FE0013A809?OpenDocument&quot; rel=&quot;nofollow noreferrer&quot;&gt;Census&lt;/a&gt;) and is &quot;married and lives in a couple family with two children&quot; and &quot;lives in a house with three bedrooms and two motor vehicles&quot;.  Feel free to make any other assumptions, and if possible, skew to the worst-case/heavy use scenario - for example, motor car and/or heating/cooling is used every day, eats red meat every meal, etc.&lt;/p&gt;&#xA;" OwnerUserId="18577" LastEditorUserId="18577" LastEditDate="2019-12-31T00:43:14.220" LastActivityDate="2019-12-31T23:06:04.930" Title="Can a person's individual carbon emissions become negative over their lifetime?" Tags="|carbon|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18836" PostTypeId="2" ParentId="18832" CreationDate="2019-12-30T22:19:07.460" Score="3" Body="&lt;p&gt;I found a decent review article by Zhang et al. (2015) covering various geo-engineering proposals that is worth reading. As for atmospheric pollution, they report that pollution should be injected at controlled altitudes into the stratosphere, where it is longer-lived. Using &lt;span class=&quot;math-container&quot;&gt;$\text{SO}_2$&lt;/span&gt;, apparently around &lt;span class=&quot;math-container&quot;&gt;$2-7 \text{Tg}$&lt;/span&gt; of stratospheric injection would be needed, which is substantially lower than the global &lt;span class=&quot;math-container&quot;&gt;$\text{SO}_2$&lt;/span&gt; emissions (e.g. Lee et al. (2011) report annual emissions around &lt;span class=&quot;math-container&quot;&gt;$50\text{Tg}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\text{S}$&lt;/span&gt;, probably the figure has decreased a bit since then).&lt;/p&gt;&#xA;&lt;p&gt;So, as for your question, it is not about simply polluting more but about controlledly injecting pollutants into the correct atmospheric layers.&lt;/p&gt;&#xA;&lt;h3&gt;References&lt;/h3&gt;&#xA;&lt;p&gt;Lee et al., SO2 emissions and lifetimes: Estimates from inverse modeling using in situ and global, space‐based (SCIAMACHY and OMI) observations, Journal of Geophysical Research Atmospheres 116 (2011), &lt;a href=&quot;https://doi.org/10.1029/2010JD014758&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1029/2010JD014758&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Zhang et al., Review of geoengineering approaches to mitigating climate change, Journal of Cleaner Production 103 (2015), pp. 898-907, &lt;a href=&quot;https://doi.org/10.1016/j.jclepro.2014.09.076&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/j.jclepro.2014.09.076&lt;/a&gt;, available at &lt;a href=&quot;http://www.homepages.ed.ac.uk/shs/Climatechange/Geo-politics/Comparisons.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.homepages.ed.ac.uk/shs/Climatechange/Geo-politics/Comparisons.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="681" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-12-30T22:19:07.460" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18837" PostTypeId="2" ParentId="18835" CreationDate="2019-12-30T22:40:31.583" Score="0" Body="&lt;p&gt;You'd have to keep your own ledger recording your greenhouse gases emissions over your lifetime; I don't think you'd find anyone mug enough to do it for you. Yes, it would be possible to plant enough trees to more than offset your emissions, provided you had the money and the land. In some countries there is probably enough unsupervised state owned land to solve the land problem. How many trees it would take depends on what kinds you planted: a mountain ash or hawthorn would remove far less carbon than a sequoia or redwood, which are about 1,000 times heavier. In American history there was a character called Johnny Appleseed who went around planting apple trees, so we may be sure that he more than offset his emissions by his tree-planting activities.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-30T22:40:31.583" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18838" PostTypeId="1" CreationDate="2019-12-31T01:36:39.897" Score="1" ViewCount="153" Body="&lt;p&gt;How much of the variance in the climate is due to the equatorial bulge and how much sun radiation do we lose due to the equatorial bulge?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am interested in the variance both through time and through location.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A more uniform surface would emit/reflect less sun radiation due to Wien's displacement law. As such we would have a higher mean temperature and less variance. I am interested in a quantitative(even if there are no exact numbers) answer and not qualitative.&lt;/p&gt;&#xA;" OwnerUserId="17030" LastActivityDate="2020-01-01T11:25:15.630" Title="Equatorial Bulge and its implications on the climate" Tags="|meteorology|climate-change|geophysics|climate|climate-models|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18839" PostTypeId="1" AcceptedAnswerId="18841" CreationDate="2019-12-31T11:47:12.447" Score="1" ViewCount="177" Body="&lt;p&gt;A new decade question: given that the “mini ice ages” were triggered by volcanic activity, how likely is it that we will experience similar levels of volcanic activity over the next 20 years?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In other words, &lt;strong&gt;if earth is capable of naturally saturating atmosphere with cooling sulphates, how likely is it that another series of such events will reverse climate change?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bonus question - can such event be forced through interference with volcanic regions or tectonic plate seams?&lt;/p&gt;&#xA;" OwnerUserId="18579" LastEditorUserId="543" LastEditDate="2019-12-31T16:15:39.333" LastActivityDate="2019-12-31T18:50:21.297" Title="How likely is Earth to naturally reverse climate change in the next 2 decades?" Tags="|meteorology|geology|climate-change|volcanology|extreme-weather|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18841" PostTypeId="2" ParentId="18839" CreationDate="2019-12-31T13:40:57.867" Score="1" Body="&lt;p&gt;Very unlikely, especially as the major industrial nations will come nowhere near to meeting their greenhouse gases emission targets. Major volcanic eruptions, like major earthquakes, are random and unpredictable. The last really big volcanic eruption we had was Tambora, on the Indonesian island of Sumbawa in 1815. That caused climate cooling for a few years, but it didn't cause a mini ice age. It may have helped the Little Ice Age which was already in progress, to last until the middle of the century, but that's all.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tambora was the biggest eruption in recorded history, dwarfing Pinatubo, Krakatoa and Thera (Thera erupted in the Med near Crete 3.5 thousand years ago and destroyed the Minoan civilisation), so an eruption big enough to cause another Little Ice Age would probably need to be as large as the Toba eruption of about 75,000 years ago on the Indonesian island of Sumatra. The chances of such an eruption within the next 20 years are virtually nil. The Little Ice Age, which lasted about 400 years and ended about 1850, is not believed to have been caused by volcanic eruptions, though such eruptions may have from time to time intensified it and prolonged it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is no way of inducing major eruptions short of detonating 50 megaton hydrogen bombs in sites known to be volcanically unstable, but that would not only violate international treaties about nuclear explosions in the atmosphere but would in any case be unacceptable. Fifty megatons is the world record for thermonuclear explosions, by the way, held by the Russians.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2019-12-31T13:40:57.867" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18842" PostTypeId="2" ParentId="18835" CreationDate="2019-12-31T21:51:02.683" Score="3" Body="&lt;p&gt;Aussies emit &lt;a href=&quot;https://www.economicshelp.org/blog/10296/economics/top-co2-polluters-highest-per-capita/&quot; rel=&quot;nofollow noreferrer&quot;&gt;~15 tonnes CO2 per capita per year&lt;/a&gt;. Current carbon capture and storage technology can bury CO2 for &lt;a href=&quot;https://www.power-technology.com/features/carbon-capture-cost/&quot; rel=&quot;nofollow noreferrer&quot;&gt;\$40-\$57 per tonne&lt;/a&gt; (estimate for early 2020s). So, yes, you could do this for ~$50,000 .&lt;/p&gt;&#xA;&lt;p&gt;Underground storage is relatively permanent. As for trees, you could plant one of &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_largest_giant_sequoias&quot; rel=&quot;nofollow noreferrer&quot;&gt;these&lt;/a&gt;,&#xA;&lt;a href=&quot;https://i.stack.imgur.com/dUDBF.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dUDBF.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;1,700 tonnes  CO2 and lives 3,000 years. With any kind of trees you will need to assure your patch of forest remains treed for millenia. As for the number of trees, I think forested area is a better measure:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UYU4a.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UYU4a.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;Approximative values of the carbon content (tonnes per hectare) for various vegetation types.&lt;br /&gt;&#xA;&lt;a href=&quot;https://jancovici.com/en/climate-change/ghg-and-carbon-cycle/cant-we-just-grow-forests-to-compensate-for-our-co2-emissions/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source : IPCC, 2001&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You would need tens of hectares.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2019-12-31T23:06:04.930" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18843" PostTypeId="1" AcceptedAnswerId="18845" CreationDate="2019-12-31T23:43:51.650" Score="3" ViewCount="174" Body="&lt;p&gt;Firstly, I would like to express my deepest condolences to those affected by the extreme heat and catastrophic wildfires on NSW's south coast and in Gippsland (east of Melbourne).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I was looking at temperature maps in Australia, I noticed something I thought was strange.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If there's extreme heat in NSW/Vic/SA, then often WA will escape the worst of it. Conversely, if Perth is going through an extreme hot spell, then eastern Australia will escape the worst of the heat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Qmiqa.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Qmiqa.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ryiv3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ryiv3.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These were the temperatures on December 25 and 30, 2019 (adjusted for time differences). As you can see, on Christmas Day, Perth was roasting, but the eastern capital cities were much cooler. And yesterday, the east coast (including Tasmania!) saw record heat, but Perth did not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't think the time difference completely explains the variance in temperature. For some reason, heat waves rarely affect all major non-tropical capital cities at once (Sydney, Melbourne, Perth, Adelaide, Canberra, Hobart). There will be one or two cities that escape the heat. I wonder why this is.&lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2020-01-05T22:46:13.873" Title="Why do heat waves affect Australia unevenly?" Tags="|meteorology|temperature|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18844" PostTypeId="2" ParentId="18843" CreationDate="2020-01-01T06:13:45.263" Score="0" Body="&lt;p&gt;The answer is very simple: Australia is continental in size. You might as well ask why some parts of Europe swelter in heat waves or suffer from droughts while at the same time of year other parts do not. On another occasion, the droughts, floods or heatwaves could be affecting different parts of Europe, Australia or whatever continent we are discussing, especially in summer when there is less temperature contrast between north and south. Australia is well known as a dry continent, and much of the interior is desert or semi-desert.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-01T06:13:45.263" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18845" PostTypeId="2" ParentId="18843" CreationDate="2020-01-01T06:42:03.223" Score="10" Body="&lt;p&gt;It primarily has to do with the pattern on high and low pressure systems as they present themselves over the continent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the southern hemisphere, high pressure systems rotate anticlockwise and low pressure systems rotate clockwise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because the north of Australia is close to the equator, generally the north of Australia has a low pressure trough over it. High pressure system tend to centered from the mid latitudes of Australia southwards.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If there is a high pressure system just to the south west of Australia, and particularly if there is a low pressure system just to the south, in the Great Australian Bight, cold air from the south will affect Perth and the south west of Australia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/S2w1E.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/S2w1E.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the high pressure system moves eastwards a low pressure trough can develop over the west coast of Australia. With or without the trough, the high pressure system moves hot air from the central and northern parts of Australia and Perth and the south west experience hot conditions. If the high pressure system is slow moving this can mean prolonged periods of hot weather - heat wave. A low pressure trough along the west coast reinforces the movement of hot air from the central and northern parts of Australia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2Te9x.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2Te9x.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With the same high pressure system over the central region of Australia, as hot is drawn from the central and northern parts of Australia over the western parts of the continent, cooler air from the Southern Ocean is drawn over the eastern part of Australia, particularly the south eastern region where Hobart, Melbourne, Canberra and Sydney are located.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the high pressure system moves to the east of Australia, particularly to the Tasman Sea, between Australia and New Zealand, hot air from the northern and central parts of Australia will be drawn over the south eastern parts of the country and the regions between Adelaide and Sydney will experience hot conditions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the &lt;a href=&quot;http://www.bom.gov.au/cgi-bin/charts/charts.browse.pl?&amp;amp;syear=2019&amp;amp;smonth=12&amp;amp;sday=01&amp;amp;eyear=2020&amp;amp;emonth=12&amp;amp;eday=14&amp;amp;pdep=14&amp;amp;pstart=112&amp;amp;idcode=IDX0102&amp;amp;list=LIST&quot; rel=&quot;noreferrer&quot;&gt;synoptic chart&lt;/a&gt; below, for 29 December 2019, there is high pressure systems to the west and east of Australia and low pressure system to the south. The effect of these systems is to draw cold air from the south over Perth and the south west of Australia and hot air from the central and northern parts of Australia to the south east of the country.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is why one part of the Australia with fry, while the other doesn't.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rcfcq.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rcfcq.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2020-01-01T06:47:34.570" LastActivityDate="2020-01-01T06:47:34.570" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18847" PostTypeId="1" AcceptedAnswerId="18848" CreationDate="2020-01-01T19:12:54.477" Score="1" ViewCount="106" Body="&lt;p&gt;I found the below chart in a test for university access in Sweden, with the following question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How large was the total emission of nitrogen oxides caused by Swedish consumption under the period 2004-2008?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have the correct solution, but it does not match my answer. I reasoned like this:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Both 2004 and 2008 should be included, so we have 5 years.&lt;/li&gt;&#xA;&lt;li&gt;The emissions abroad are about 112 thousand tons on average, so 112*5 = 560&lt;/li&gt;&#xA;&lt;li&gt;The emissions in Sweden are about 225 thousand tons on average, so 225*5 = 1100.&lt;/li&gt;&#xA;&lt;li&gt;So the total should be about 160+1100 = 1660.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;However, apparently the correct answer is 1100.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am quite sure I am missing something obvious, but I cannot figure it out.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Translation of the most important terms:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Utsläpp i Sverige: emission in Sweden&lt;br&gt;&#xA;Utsläpp utomlands: emission abroad (caused by imports).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qnbkK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qnbkK.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The original question in Swedish:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Hur stort var det sammanlagda utsläppet av kväveoxider orsakat av svensk konsumtion under perioden 2004-2008?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="18584" LastEditorUserId="18584" LastEditDate="2020-01-01T19:19:24.447" LastActivityDate="2020-01-01T19:45:37.423" Title="How to interpret correctly this chart about nitrogen oxide?" Tags="|nitrogen|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18848" PostTypeId="2" ParentId="18847" CreationDate="2020-01-01T19:45:37.423" Score="2" Body="&lt;p&gt;A person answered to me on a &lt;a href=&quot;https://www.facebook.com/groups/468485986570404/permalink/2647172855368362/?comment_id=2647181812034133&quot; rel=&quot;nofollow noreferrer&quot;&gt;dedicated Facebook group&lt;/a&gt;. He suggests that the labels are about areas, not lines, so the grey area (emissions in Sweden), is only the visible area, it does not continue below the dark area (emissions abroad). I find this representation very confusing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an example, the emissions in Sweden in 2008 are 225 - 100 = 125, the difference between the total and the dark area, and not 100 as I thought.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This way, the correct answer is 1100, because the upper line already represents the total emissions, and between 2004 and 2008 we have an average of 225 for 5 years.&lt;/p&gt;&#xA;" OwnerUserId="18584" LastActivityDate="2020-01-01T19:45:37.423" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18849" PostTypeId="1" CreationDate="2020-01-01T20:04:29.997" Score="1" ViewCount="164" Body="&lt;p&gt;How many different storms, thunderstorms, snow storms, hurricanes, typhoons, what have you, are happening in the Earth our planet at any given point in time. Furthermore, I imagine they are over the water mostly, is this true?&lt;/p&gt;&#xA;" OwnerUserId="18586" LastActivityDate="2020-01-01T20:04:29.997" Title="How many storms are happening on Earth at a given moment?" Tags="|earth-system|storms|" AnswerCount="0" CommentCount="3" ClosedDate="2020-01-02T10:09:28.077" ContentLicense="CC BY-SA 4.0" />
  <row Id="18851" PostTypeId="2" ParentId="18594" CreationDate="2020-01-02T11:07:02.857" Score="3" Body="&lt;p&gt;It is likely that the forecast is made using an ensemble of runs from a weather model.  As weather is chaotic (deterministic, but heavily dependent on initial conditions), each run will show a different pattern of precipitation, and the probability is likely to be simply the proportion of model runs that exhibited precipitation in that location during that hour.  Sometimes the pattern in each model will be very similar (e.g. a weather front going through) or they may be very different (AIUI convective rainfall, e.g. thunderstoms, are less predictable, so each run may have a broad pattern of isolated showers, but you will miss them in some runs but not in others).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that &quot;location&quot; will mean the grid box in the weather model (km^2?), it doesn't mean that it will rain everywhere in that grid box, and definitely not a cup.  I used to play cricket quite regularly at a place with three cricket pitches all within sight of eachother.  I can remember several occasions where it was raining on one pitch, but not another (play stopped on one pitch but carried on on the other).&lt;/p&gt;&#xA;" OwnerUserId="624" LastActivityDate="2020-01-02T11:07:02.857" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18852" PostTypeId="1" AcceptedAnswerId="18853" CreationDate="2020-01-02T12:16:35.350" Score="2" ViewCount="1296" Body="&lt;p&gt;In section 1.7 of &lt;a href=&quot;https://www.cambridge.org/core/books/geodynamics/E0E847DA9FE68BDB90C2E457791F0C98&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geodynamics&lt;/a&gt; by D. Turcotte &amp;amp; G. Schubet it is stated that &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;em&gt;&quot;(...) continental crust cannot be destroyed by subduction&quot;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;which I cannot completely understand. So far I understand the oceanic lithosphere sinks at the trenches because it cools down and becomes denser (thermal contraction) as it moves away from the ocean ridges. So the logic is: buoyancy will make it descend.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But then again, isn't the continental crust thicker and denser? By the same logic above, it should sink as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Am I missing something? Thanks in advance for any comments&lt;/p&gt;&#xA;" OwnerUserId="18588" LastActivityDate="2020-01-02T14:16:48.130" Title="why continents do not subduct" Tags="|geodynamics|continental-rifting|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18853" PostTypeId="2" ParentId="18852" CreationDate="2020-01-02T14:16:48.130" Score="4" Body="&lt;p&gt;It is continental crust which hs the greater buoyancy, so when it meets another plate of continental crust neither can subduct. Instead, they collide, crumple and fold, making them thicker and higher. An example of this is the collision between the Indo-Australian plate and the Eurasian plate, which has formed the Himalayas. Had the Indo-Australian plate been oceanic plate, which is thinner and less buoyant, it would have been subducted.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-02T14:16:48.130" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18854" PostTypeId="1" AcceptedAnswerId="18855" CreationDate="2020-01-02T17:00:40.567" Score="14" ViewCount="5711" Body="&lt;p&gt;I went to Mexico and the pyramids are covered by vegetation. It's only after archeologists clean them that you can actually see the pyramids. Before that they looked like a natural hill, with soil, trees, ...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How is that possible? I can imagine grass or small weeds growing here and there in between the stones with seeds being disseminated by wind or birds. But how did soil get up there? Whatever 'lucky parts' of soil that got up there should be washed off with gravity, wind, rain, no?&lt;/p&gt;&#xA;" OwnerUserId="18591" LastEditorUserId="2470" LastEditDate="2020-01-02T17:48:38.100" LastActivityDate="2020-09-04T03:38:43.633" Title="How did forests end up covering pyramids?" Tags="|forest|soil-science|vegetation|natural-conditions|" AnswerCount="5" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18855" PostTypeId="2" ParentId="18854" CreationDate="2020-01-02T17:46:27.690" Score="15" Body="&lt;p&gt;The accumulation of soil in such situations takes a long time. The main way soil would have been naturally transported there would be by the wind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The wind blown soil would get caught and accumulate. Plants, particularly grasses, would grow on the soil and the plant roots would create mesh that would protect the soil from erosion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You are correct in that some soil would be lost due to erosion (predominantly via rain and wind), but the soil protected by the plant roots would remain. Over time the cycle repeats and soil slowly accumulates. The accumulation of the soil initially occurs at the base of the pyramid and gets deeper, eventually covering the pyramid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gravity would not cause soil loss. There may be some localized soil slumping if a soil face was too steep, but it wouldn't more far. The effect of gravity would be to keep the overall long term slope of the soil at the &lt;a href=&quot;https://en.wikipedia.org/wiki/Angle_of_repose&quot; rel=&quot;noreferrer&quot;&gt;angle of repose&lt;/a&gt; of the soil.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-01-02T17:46:27.690" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18856" PostTypeId="2" ParentId="18854" CreationDate="2020-01-02T18:41:16.457" Score="4" Body="&lt;p&gt;Most of the Mexican pyramids are less steep than their Egyptian counterparts, and have niches and terraces which their Egyptian counterparts don't. An important difference is the climate, which is much damper in Mexico, and shows how the rainforest can reclaim areas where it has been eradicated if the site is then abandoned. Yet another factor is the type of stone used, some types weather more easily than others. I think some Mexican pyramids have been built from limestone, which is very susceptible to erosion. The dust and debris from the weathered stone mixes with plant debris and forms soil, making it easier for more trees and bushes to take root. The plant roots help keep the soil in place. In cleared rainforest, jungle indistinguishable from primary rainforest can take over in only 50 years, so no wonder it has re-established on pyramids well over 1,000 years old. They have had the same problem at Ankor Wat in Cambodia, where much clearance of the temples has had to be done.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-02T18:41:16.457" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18857" PostTypeId="2" ParentId="7212" CreationDate="2020-01-02T22:56:22.953" Score="1" Body="&lt;p&gt;The water in your pond has to lower to below freezing.  It takes time for the heat of the water to transfer to the surroundings.  The ground underneath the water probably isn't below freezing either, so it will be transferring heat to the water at the same time.  Looking at the &lt;a href=&quot;https://www.wunderground.com/history/monthly/us/mo/st.-louis/KSTL/date/2016-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;temperature history&lt;/a&gt; for the time in question, the high temperatures for all the days around were above freezing and the average temperatures were near or higher than freezing as well.  It takes more than a day for a large quantity of water to lose that much heat to the environment when it is near that temperature anyway.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could do your own experiment getting different sized bottles of water and seeing how long it takes each one to freeze in the same conditions.  It takes a lot more energy loss to change the state of water from liquid to solid.  4200 J/liter/degree(C) to change the temperature of water, 333,000 J to crystallize a liter of water.  So to completely freeze the pond, it's surroundings would have to absorb the same amount of energy as it would take to lower the temperature nearly 80 degrees celsius.&lt;/p&gt;&#xA;" OwnerUserId="13537" LastActivityDate="2020-01-02T22:56:22.953" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18858" PostTypeId="1" CreationDate="2020-01-03T03:13:30.007" Score="2" ViewCount="281" Body="&lt;p&gt;How can I find the average number of days with thunderstorms for each month for different cities in the United States? I’m doing a researching project for this and I need to find some links that will show me the average number of days with thunderstorms for each month for different cities in the United States.&lt;/p&gt;&#xA;" OwnerUserId="17923" LastEditorUserId="18081" LastEditDate="2020-01-03T11:13:33.213" LastActivityDate="2020-02-06T09:34:56.273" Title="Average thunderstorm days for each month" Tags="|open-data|thunderstorm|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18859" PostTypeId="2" ParentId="18854" CreationDate="2020-01-03T05:29:26.887" Score="2" Body="&lt;p&gt;Disclaimer: this answer is based on what I remember from school and TV.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When a volcano erupts with lava flows, the magma cools and forms an inhospitable, sterile surface. The first life to colonise the rocky surface is lichens. When the lichens start dying, they decay into very thin soil layers. Next comes moss which needs a tiny bit of soil. The roots of the moss keep the soil where it is. Some old moss is decaying while new moss keeps the new soil where it is. Lichens are still present. Eventually wind or bird borne seeds are deposited on the soil and can sprout into small plants, and finally trees.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The American pyramids are similar except that they are in a lush rain forest and were not as sterile as a volcano when they were built. The surface of both the pyramids and cooled magma have enough small cracks that plant roots can get into. Roots can exert an amazing amount of pressure over a long period of time, so they gradually widen the cracks which allows more soil to collect, and more plant growth, accelerating the process.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main force that prevents erosion is plant roots.&lt;/p&gt;&#xA;" OwnerUserId="5417" LastActivityDate="2020-01-03T05:29:26.887" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18860" PostTypeId="2" ParentId="18824" CreationDate="2020-01-03T09:23:09.547" Score="3" Body="&lt;p&gt;Although not exactly a textbook, I would highly recommend you to read Marcia Bjornerud's &lt;a href=&quot;https://press.princeton.edu/books/hardcover/9780691181202/timefulness&quot; rel=&quot;nofollow noreferrer&quot;&gt;Timefulness&lt;/a&gt; (2018). It goes through all of Earth's history, including the atmosphere. It's short and kind of poetic, but backed by solid science. Her previous book, &lt;em&gt;Reading the Rocks&lt;/em&gt;, seems somewhat similar (it's subtitle is &lt;em&gt;The Autobiography of the Earth&lt;/em&gt;), but I did not read it. It was also praised at the time, so it might be worth reading even if it lacks the more recent discoveries (it's from 2005).&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-01-03T09:23:09.547" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18861" PostTypeId="2" ParentId="18858" CreationDate="2020-01-03T10:10:31.830" Score="2" Body="&lt;p&gt;You should start with NOAA services. They have a &lt;a href=&quot;https://www.ncdc.noaa.gov/stormevents/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Storm Events Database&lt;/a&gt; going back to 1950, where you can do queries for states/counties of interest. If you are more interested in lightning data, they also have &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/severe-weather/lightning-products-and-services&quot; rel=&quot;nofollow noreferrer&quot;&gt;some products&lt;/a&gt;, including raw data from a private company (you'll need access for this) and freely available derived products.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-01-03T10:10:31.830" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18862" PostTypeId="2" ParentId="18854" CreationDate="2020-01-03T16:45:47.517" Score="51" Body="&lt;p&gt;I am an archaeologist and I specialize in the ancient Maya. Here's how it happens:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1: The vast majority of ancient Maya buildings are built using a &quot;core and veneer&quot; technique. The bulk of the building's volume is earth and stone rubble, faced with a veneer of nicely-shaped limestone blocks that are themselves covered by a layer of lime plaster (stucco). The geology of the Yucatan peninsula is almost entirely limestone, so they built with what they had available.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2: Most pyramids have multiple construction phases, with each one adding a new layer of rubble/earthen core and cut stone and stucco veneer. The building gets bigger with each renovation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3: Following abandonment, strong seasonal rains quickly erode the lime stucco on much of the outermost layer. This eroded stucco is chemically and structurally identical to the eroded bedrock that underlies natural soils in the Maya region, meaning that plants can readily grow on it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;4: The limestone used for cut stone veneers is itself really porous and prone to crack, pit, and erode in most parts of the Maya lowlands. I am constantly seeing small trees growing out of ostensibly solid blocks of limestone--their roots can still get plenty of purchase. As such, trees can easily take hold in the space between blocks and in small imperfections in the stones themselves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;5: As the trees grow (and especially as their roots push or pry out loosened veneer stones), the cut stones from the veneer give way, exposing the earthen/rubble core underneath. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;6: Other posters are correct that some topsoil builds up as a result of wind-transported dust and decaying plant matter, but this is a very, very small amount, especially on the steeper upper portion of the building (remember, the buildings become less steep overall as they erode, because what had been on the upper part tumbles down and piles up around the base, reducing the gradient). Instead, most of the &quot;soil&quot; was actually put there by the Maya as part of the final construction phase, covered by a layer of modern humus.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;7: It follows that in many parts of the Maya world, what you see when you look at a cleared/restored pyramid is not really what it looked like in its final stage. Instead, it's usually a mix of the last and second-to-last construction phases, both having been subject to varying degrees of erosion, with the last phase usually only preserved toward the bottom and at the very top.&lt;/p&gt;&#xA;" OwnerUserId="18595" LastActivityDate="2020-01-03T16:45:47.517" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18864" PostTypeId="1" CreationDate="2020-01-03T22:14:25.423" Score="1" ViewCount="32" Body="&lt;p&gt;I am trying to find historical humidity levels (ideally in percentage format) across the globe divided by sub-country regions or more granular. &lt;BR&gt;&#xA;The time granularity would be daily, but hourly would be preferred. I do not have a historical range preference as long as there's enough data for at least a year. &lt;BR&gt;&#xA;Any open data source where I could find this information? NOAA station data seem to be limited to temperature/precipitation. &lt;br&gt;&#xA;Google searches return corporate solutions in the thousands of dollars, which are not an option.&lt;/p&gt;&#xA;" OwnerUserId="18601" LastActivityDate="2020-01-03T22:14:25.423" Title="Finding free humidity data" Tags="|meteorology|open-data|humidity|" AnswerCount="0" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18865" PostTypeId="1" CreationDate="2020-01-04T02:39:15.323" Score="1" ViewCount="916" Body="&lt;p&gt;I want travel Japan but it gets earth quakes, tsunamis, typhoons. Which months lowest probability of these natural disasters? &lt;/p&gt;&#xA;" OwnerDisplayName="user17042" LastActivityDate="2020-01-05T15:54:46.167" Title="Which months in Japan probability lowest of natural disaster?" Tags="|predictability|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18866" PostTypeId="1" CreationDate="2020-01-04T05:41:11.820" Score="3" ViewCount="604" Body="&lt;p&gt;Most people knows that the ocean overall is a carbon sink, but a big part of the sink is due to chemical equilibrium (via dissolution) with the atmosphere (for ref: &lt;a href=&quot;https://link.springer.com/article/10.1007/s10021-005-0036-3&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://link.springer.com/article/10.1007/s10021-005-0036-3&lt;/a&gt;). Not all the (chemically) dissolved CO2 is consumed by primary producers in the ocean (simple deduction from ocean acidification). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terrestrial ecosystems, we have a term called net ecosystem production (NEP) which is defined as gross primary production minus the total (autotrophic + heterotrophic) respiration in an ecosystem (generally a meaningful timeframe should be at least on an annual basis). I wonder is there any research done regarding the NEP of the ocean? (I am sure there are some out there but I cannot find a conclusive summary of the entire ocean or at least a big part of the ocean). I am assuming this would be harder to measure than terrestrial ecosystems considering how big the ocean is and the big confounding factor of physicochemical processes in the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: I found somebody trying to answer the same question 20 years ago (Del Giorgio, P. A., &amp;amp; Duarte, C. M. (2002). Respiration in the open ocean. Nature, 420(6914), 379). But in it, it said the answer remained uncertain. I am assuming there would be advances since then.&lt;/p&gt;&#xA;" OwnerUserId="3241" LastEditorUserId="3241" LastEditDate="2020-01-05T23:16:01.767" LastActivityDate="2020-02-05T00:02:45.353" Title="Is the ocean a carbon sink when considering only the biospheric component?" Tags="|oceanography|carbon-cycle|biogeochemistry|ecology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18867" PostTypeId="2" ParentId="18865" CreationDate="2020-01-04T05:43:05.317" Score="3" Body="&lt;p&gt;There is no season for earthquakes or tsunamis. They can hit at any time of the year, and at any time of the day or night.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Typhoons happen in the warm season, but they will be forecast by the meteorological service, giving you time to move to a safe area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to go to Japan, just go. It is better to go in the season you want to go than to try and avoid earthquakes and typhoons, as they happen in random places out of anybody's control.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6467" LastEditDate="2020-01-05T15:54:46.167" LastActivityDate="2020-01-05T15:54:46.167" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18868" PostTypeId="2" ParentId="18866" CreationDate="2020-01-04T10:00:34.753" Score="1" Body="&lt;p&gt;Yes, the marine biosphere is a carbon sink, and a very important one. It is known that the oceans produce more oxygen and biologically consume more carbon dioxide than all the tropical rainforests. This is done by microscopic blue-green algae, cyanobacteria and phytoplankton of many kinds. Also by green algae such as seaweeds, by sea grass meadows, and by coral reefs which are built of calcium carbonate synthesised by the corals themselves. Sea grass is an interesting plant, related to land grasses but able to survive and prosper in shallow seas where there is plenty of light and suitable soil. It is very important for the marine ecosphere. As on land, there are marine deserts where there is very little biological activity, and other areas that are teeming with life.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question arises of how much of this captured carbon remains in the sea. The answer is most of it, but it is impossible to give exact figures. Some of the marine biomass is removed by various means, fishing for example, but that does not mean that all the carbon is returned to the atmosphere. Sea birds consume a lot of fish, and much of their guano is deposited on land, and some of them die on land, but again not all the carbon is returned to the atmosphere. There are enormous deposits of guano on the coast of South America and some Pacific islands, which are mined for fertiliser. The bodies of dead marine creatures, and sometimes live ones, are often consumed by other marine creatures. A dead whale, for example, provides a feast for all sorts of marine carnivores and scavengers. Much of the marine biomass eventually sinks to the ocean floor, where it becomes part of the ooze and sediment. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-04T10:00:34.753" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18869" PostTypeId="1" AcceptedAnswerId="18871" CreationDate="2020-01-04T10:36:19.127" Score="6" ViewCount="485" Body="&lt;p&gt;Given the vastness and intensity of the bushfires that have been going on in Australia for weeks now, to the point they are &lt;a href=&quot;https://www.sciencealert.com/the-bushfires-in-australia-are-so-big-they-re-generating-their-own-weather&quot; rel=&quot;nofollow noreferrer&quot;&gt;generating their own weather&lt;/a&gt; and having an &lt;a href=&quot;https://glacierhub.org/2020/01/03/photo-friday-bushfires-in-australia-continue-to-devastate-new-zealand-glaciers/&quot; rel=&quot;nofollow noreferrer&quot;&gt;impact thousands kilometers away&lt;/a&gt; from their origin, an analogy with volcanic eruptions spurred to my mind and I wondered: could the net effect of these bushfires actually be a measurable cooling down of global temperature, as it happened with &lt;a href=&quot;https://earthobservatory.nasa.gov/images/1510/global-effects-of-mount-pinatubo&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mount Pinatubo&lt;/a&gt;, at least in the short term?&lt;/p&gt;&#xA;" OwnerUserId="18604" LastEditorUserId="18584" LastEditDate="2020-01-06T06:22:43.430" LastActivityDate="2020-01-06T06:22:43.430" Title="Could Australia's bushfires aerosols actually decrease global temperature?" Tags="|meteorology|climate-change|wildfire|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18870" PostTypeId="2" ParentId="18869" CreationDate="2020-01-04T12:53:32.347" Score="-2" Body="&lt;p&gt;It is unlikely that the Australian fires will produce enough particulates by themselves to induce measurable global dimming, but we can't be sure because the fires are not yet finished and could continue for months. Another thing to remember is that Australia is not the only country to have major wildfires, so it seems probable that the combined effects of all these fires on global dimming may be measurable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;People worried about all the CO2 being poured into the atmosphere by these wildfires&#xA;should bear in mind that if the drought is followed by a wet period,the forest will regenerate and recapture an amount of CO2 equivalent to the amount they have released. Major eruptions like Pinatubo release colossal amounts of CO2, but unlike burning forests have no mechanism whereby they can suck most of it back in the fulness of time. They also release vast quantities of dust particles high into the atmosphere, accompanied by large amounts of sulphur dioxide which reflects solar radiation back into space, so that explains the cooling effect such major eruptions have. It usually doesn't last very long.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-04T12:53:32.347" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18871" PostTypeId="2" ParentId="18869" CreationDate="2020-01-04T17:30:24.243" Score="6" Body="&lt;p&gt;Well, the amount and intensity of wild fires are a direct outcome of global warming, that's not really news.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://www.theguardian.com/environment/2019/dec/13/australias-bushfires-have-emitted-250m-tonnes-of-co2-almost-half-of-countrys-annual-emissions&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; that cites a work i can't find, until the mid of December 2019 the Australian fires emitted ~250million tons of carbon, ~50% of Australia's yearly production. A recovery in the coming decades is unlikely, because the ecosystem is already compromised. It is &quot;too optimistic&quot; to assume that the forests will regrow and they will &quot;never end up accumulating as much carbon as they had before&quot;. Instead, large areas of burning forests must more and more be seen as a biospheric component that can turn from a carbon sink to a source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's &lt;a href=&quot;https://www.nature.com/articles/s41586-019-1474-y&quot; rel=&quot;nofollow noreferrer&quot;&gt;an example&lt;/a&gt; (sorry paywalled, but the abstract has the interesting points and it is peer reviewed) for boreal forest fires, where fires can lead from net accumulation over several fire events to a net loss, leading to a positive feedback. A similar process is expected for the Amazon rain forest fires.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To the question: an exact answer seems to be difficult. It depends on how much aerosols end up where in the atmosphere and stays for how long. The effect can be &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2009GL038435&quot; rel=&quot;nofollow noreferrer&quot;&gt;modelled&lt;/a&gt;: Here, a fire aerosol laiden atmosphere's lower 6km can be warmed because they become a heat trap. The trap is caused because aerosols have a stabilizing effect on the upper atmosphere. A forest fire's plume has a different composition than a volcanic eruption !&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This &lt;a href=&quot;https://www.nature.com/articles/ngeo156&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt; describes a similar effect, the absorption of solar radiation by carbon can heat the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am aware that there may be other effects, inclduing atmospheric cooling, but i leave that part to somebody else. All in all, the negative effects of carbon release and the potential loss of regenerative abilities of the biosphere - because of &lt;a href=&quot;https://onlinelibrary.wiley.com/doi/abs/10.1111/ele.12889&quot; rel=&quot;nofollow noreferrer&quot;&gt;drought&lt;/a&gt;, erosion, loss of biodiversity and the ecosystem, soil sterilization, invasive organisms as well as the difficulties to respond in time because of the sheer area affected by fire (all depending on intensity, duration and area) - by far outweigh any cooling effects of wild fires.&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-04T20:22:43.097" LastActivityDate="2020-01-04T20:22:43.097" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18872" PostTypeId="2" ParentId="17628" CreationDate="2020-01-04T17:40:33.390" Score="2" Body="&lt;p&gt;Simple answer: No. The process &quot;carbon sequestration&quot; considers the whole Earth system holistically (otherwise it would not serve its purpose), and in your case, you only look at the plant-atmosphere system so nothing can be said of the amount of carbon sequestered. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What you are describing is more close to &lt;strong&gt;&lt;em&gt;Net Primary Production&lt;/em&gt;&lt;/strong&gt;, which is defined as carbon fixation from photosynthesis minus carbon released from autotrophic respiration (which is somewhat different from transpiration that you mentioned).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Carbon sequestration refers to the transfer of atmospheric carbon into a relatively stable pool of carbon (on a climate-relevant time scale, usually at least in decadal-scale). &quot;New growth&quot; implies all the biomass gains of the tree over time, not necessarily &quot;stable&quot; biomass only. One obvious case arises for deciduous trees where large portion of &quot;gained&quot; leaves fall and decompose relatively rapidly. &lt;/p&gt;&#xA;" OwnerUserId="3241" LastEditorUserId="3241" LastEditDate="2020-01-05T07:10:45.967" LastActivityDate="2020-01-05T07:10:45.967" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18873" PostTypeId="1" AcceptedAnswerId="18877" CreationDate="2020-01-04T20:27:08.350" Score="8" ViewCount="1568" Body="&lt;p&gt;The figure below is taken from &lt;a href=&quot;https://ui.adsabs.harvard.edu/abs/2019JGRB..124..195R/abstract&quot; rel=&quot;noreferrer&quot;&gt;Reath, K. et al. (2019)&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A couple of things can be seen from this representation&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Volcanism seems to be strongly correlated with subduction zones, in this case the Nazca plate and South America plates.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;There is a significant gap of volcanoes in both Peru and Chile. Which suggests that subduction is not the whole story. There must be something else happening&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Question is: do we know what? What is the reason for these gaps?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wJhvW.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wJhvW.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18588" LastEditorUserId="2470" LastEditDate="2020-01-05T05:38:22.020" LastActivityDate="2020-01-05T21:35:18.183" Title="Gaps in locations of volcanos (Peru &amp; Chile)" Tags="|volcanology|plate-tectonics|geodynamics|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18875" PostTypeId="2" ParentId="18873" CreationDate="2020-01-05T08:36:51.257" Score="0" Body="&lt;p&gt;When an oceanic plate is subducted below a continental plate, it dives into the mantle, taking water with it and producing frictional heat which melts some of the rock (rock with a high water content melts more easily). This produces plumes of magma beneath the continental plate margins. As the magma is lighter than the mantle material, it rises until it meets the continental plate above. The plumes try to break through, but are not always successful. Those that break through form volcanoes, those that don't quite manage to break through form plutons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looking at your map, we see gaps where the magma plumes have so far failed to break through, perhaps in places where the crust was thicker. In places where it seems there should be more volcanoes, there could be plutons marking a failed attempt, or there could still be a rising plume which might one day succeed in reaching the surface. Close to a line of volcanoes, it could be that these volcanoes are bleeding off so much of the rising magma that the remainder finds it hard to break through to the surface.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-05T08:36:51.257" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18876" PostTypeId="2" ParentId="18873" CreationDate="2020-01-05T09:59:39.383" Score="5" Body="&lt;p&gt;So, &lt;a href=&quot;https://en.wikipedia.org/wiki/Andean_Volcanic_Belt&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; is the setting. A relatively &lt;a href=&quot;https://en.wikipedia.org/wiki/Nazca_Plate&quot; rel=&quot;nofollow noreferrer&quot;&gt;young plate&lt;/a&gt; plate is subducted under the south American continent. The subducting oceanic plate contains water that is squeezed out under pressure and starts to rise. Water (fluids) generally &lt;a href=&quot;http://www.tulane.edu/~sanelson/Natural_Disasters/volcan&amp;amp;magma.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;lower the melting point&lt;/a&gt;, so hot asthenosphere above the colder subducting plate &lt;a href=&quot;https://en.wikipedia.org/wiki/Partial_melting&quot; rel=&quot;nofollow noreferrer&quot;&gt;partially melts&lt;/a&gt;, the magma, being more mobile, begins to rise and eventually reaches the surface, forming a &lt;a href=&quot;https://en.wikipedia.org/wiki/Continental_arc&quot; rel=&quot;nofollow noreferrer&quot;&gt;volcanic arc&lt;/a&gt; that sketches the subduction zone on the suurface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So why are there volcanoes in some parts of the subducting plate, and not in others ? This is a temporary state. At present &lt;a href=&quot;http://www.geo.umass.edu/structure/StrSem/Ramos-Folguera-GSL-Spec-Pub-2009.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;ridges are subducted&lt;/a&gt; in these zones. These ridges are warm and less buoyant than the surrounding plate, they don't pass the asthenosphere but slide (after a short dip) (near) horizontally under the continental crust, causing uplift and orogeny (mountain rise). In the past, there has been volcanism in these zones as well, when steeper subduction took place.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, yes, subduction is the whole story, but the type of subduction plays a role. The last link describes the current understanding of how these areas with volcanism will shift with subduction of the ridges, as well as sketches of the subduction types, as pictured by seismics.&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-05T12:02:12.380" LastActivityDate="2020-01-05T12:02:12.380" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18877" PostTypeId="2" ParentId="18873" CreationDate="2020-01-05T10:22:39.367" Score="12" Body="&lt;p&gt;As you said, the Andean belt is divided into four segments, usually called the northern, central, southern, and austral volcanic zones (NVZ, CVZ, SVZ and AVZ, respectively; your map lacks the AVZ). This has been interpreted as a difference in the angle of subduction. Under the active zones, the subducting plate (called &quot;slab&quot;) sinks into the mantle, releasing water, and the hydrated mantle partially melts, a process called &quot;metasomatism&quot;. But &lt;strong&gt;under the gaps, the slab has a low angle (&quot;flat slab subduction&quot;), so it doesn't sink deep enough to trigger the melting process&lt;/strong&gt;. There is no partial melting of the mantle under these zones.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, why has the slab failed to sink under these zones? This is due to the presence of submarine ridges. Between the NVZ and CVZ, there is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Nazca_Ridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nazca Ridge&lt;/a&gt;. Similarly, there is the Juan Fernandez ridge between the CVZ and SVZ. Those ridges are young, making the oceanic crust less dense, thus more buoyant (usually it is old, dense oceanic crust that subducts). The ridges also make the oceanic crust thicker, thus harder to subduct.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zs7t1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zs7t1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sub&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/File:MAGMAARC1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Image source&lt;/a&gt;; by &lt;a href=&quot;https://en.wikipedia.org/wiki/User:Chiton_magnificus&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chiton magnificus&lt;/a&gt; in 2011 and placed in the public domain.&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Two papers if you want to go further:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://doi.org/10.1016/0040-1951(83)90112-9&quot; rel=&quot;nofollow noreferrer&quot;&gt;Volcanic gaps due to oblique consumption of aseismic ridges&lt;/a&gt;  &lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://doi.org/10.1029/1999TC001152&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geodynamics of flat subduction: Seismicity and tomographic constraints from the Andean margin&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="1199" LastEditDate="2020-01-05T21:35:18.183" LastActivityDate="2020-01-05T21:35:18.183" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18878" PostTypeId="1" CreationDate="2020-01-05T14:48:37.750" Score="1" ViewCount="326" Body="&lt;p&gt;Venus is a runaway greenhouse planet, so it won't let any of the heat absorbed from the Sun out by radiation, yet it will still take rays of energy from the Sun. So what will happen to Venus? Will it overheat? And if it will overheat, what will actually happen to it? I couldn't find any speculations over the internet...&lt;/p&gt;&#xA;" OwnerUserId="18617" LastActivityDate="2020-01-10T07:26:51.133" Title="Will Venus eventually overheat? When it happens, what will happen to it exactly?" Tags="|planetary-science|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18879" PostTypeId="2" ParentId="18878" CreationDate="2020-01-05T15:08:18.300" Score="1" Body="&lt;p&gt;Venus does radiate away heat, but not enough to prevent the surface and lower atmosphere heating to 460C. Too late to prevent overheating, it has already overheated. In the long term, its atmosphere will gradually leak away into space, reducing the present pressure of 90 Earth atmospheres. Exactly how far this process will have gone in 5 billion years' time when the sun swells up to become a red giant is impossible to say. When the sun becomes a red giant, Venus will be inside its tenuous outer layers and therefore scorched by much higher temperatures than it has now, probably reduced to a ball of molten rock spiralling inwards towards the sun's interior.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-05T15:08:18.300" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18880" PostTypeId="2" ParentId="4980" CreationDate="2020-01-05T17:49:36.887" Score="1" Body="&lt;p&gt;The forces of a magnetic field on materials that are not ferromagnetic and not electric conductors are negligible compared to pressure, tension, and buoyancy. It is likely safe to ignore them for the upper mantle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the lower mantle is a semiconductor with a significant thermal gradient, which induces electrical gradient via thermoelectricity. This &lt;a href=&quot;https://m.scirp.org/papers/78851&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt; suggests this effect can be strong enough to actually be a source of geomagnetism. If true, it is also strong enough to interact with geomagnetic field to produce mechanical forces, which would manifest as a depth-oriented gradient of East-west drag.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another paper claims both geomagnetism and plate tectonics have the same cause: &lt;a href=&quot;https://arxiv.org/abs/0709.1303&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global coupling at 660 km is proposed to explain plate tectonics and the generation of the earth's magnetic field&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="18619" LastEditorUserId="18619" LastEditDate="2020-01-05T18:23:26.887" LastActivityDate="2020-01-05T18:23:26.887" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18882" PostTypeId="2" ParentId="17674" CreationDate="2020-01-05T19:06:52.913" Score="1" Body="&lt;p&gt;So, there's really two questions here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) if we were to take wood and store it in a way that prevents decomposition, would this help reduce atmospheric CO2? and &lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) Would sinking it into the bottom of an ocean trench achieve this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, first things first, yes removing wood from the contemporary carbon cycle does reduce atmospheric CO2. We already do this (at least temporarily) by using timber for making things - depending on the type of product this has a half-life of anything from a couple of years (paper or biomass fuel) to about 50 (for sawlogs). You can achieve a similar effect by planting new forests - so carbon is locked up in living biomass.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We could come up with a more permanent solution, and this would have to be economic (and not require more CO2 emissions to accomplish than we saved in the first place). Current research is looking at sequestration of carbon as charcoal (as this is more biologically stable than wood which is a source of food for a lot of species). This can either be spread on the land as biochar, or I suppose buried terrestrially - I'm thinking of abandoned coal mines.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not aware of deep sea storage as a widely considered option, and I suspect that this is mainly due to the techno-economic cost, and lack of research - the debate is still ongoing for many other more established carbon sequestration technologies. I don't believe there has been much investigation into the stability of wood in deep water (though it lasts for thousands of years in anoxic peat bog conditions - so I see no obvious reason why it wouldn't work).&lt;/p&gt;&#xA;" OwnerUserId="18621" LastActivityDate="2020-01-05T19:06:52.913" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18883" PostTypeId="2" ParentId="15177" CreationDate="2020-01-05T19:25:17.127" Score="2" Body="&lt;p&gt;The short answer is that using atmospheric nitrogen as a feedstock for industrial processes doesn't really affect the climate per se. It does mess with the environment (primarily through deposition of nitrogen fertiliser) but this is a separate issue. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem from a climate point of view, is that the process is virtually certain to emit a lot of greenhouse gasses (primarily CO2 from fossil fuel powered machinery)&lt;/p&gt;&#xA;" OwnerUserId="18621" LastActivityDate="2020-01-05T19:25:17.127" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18884" PostTypeId="2" ParentId="16459" CreationDate="2020-01-05T20:08:04.987" Score="0" Body="&lt;p&gt;&lt;a href=&quot;https://arxiv.org/pdf/1509.00427&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Role of Plate Tectonic-Climate Coupling and Exposed Land Area in the&#xA;Development of Habitable Climates on Rocky Planets&lt;/a&gt; cites a few references for the global carbon cycle model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The diagram on page 8 seems to imply that subduction is the only sink.&lt;/p&gt;&#xA;" OwnerUserId="18619" LastActivityDate="2020-01-05T20:08:04.987" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18885" PostTypeId="2" ParentId="18248" CreationDate="2020-01-05T21:43:59.240" Score="0" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Although conventional oil, gas and&#xA;  coal reserves total between 829 and 1,501 GtC, estimates of the global recoverable fossil fuel resource including oil shales range upwards from about 4,000&#xA;  GtC. If exotic resources, especially methane hydrates, are included the total&#xA;  may be 15,000-25,000.&lt;br&gt;&#xA;  &lt;a href=&quot;https://www.researchgate.net/publication/225712889_Millenial_timescale_carbon_cycle_and_climate_change_in_an_efficient_Earth_system_model&quot; rel=&quot;nofollow noreferrer&quot;&gt;Millenial timescale carbon cycle and climate change in an efficient Earth system model&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://ccdatacenter.org/documents/RFandCS.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;There are 2.12 GTC for 1 PPM of atmospheric CO2&lt;/a&gt; so the high estimate would be ~10,000 ppm, or 1% of the atmosphere, consuming 5% the O2. If the FF are mostly CH4, the hydrogen would consume another 5% of the O2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also &lt;a href=&quot;https://thinkprogress.org/exclusive-elevated-co2-levels-directly-affect-human-cognition-new-harvard-study-shows-2748e7378941/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Elevated CO2 Levels Directly Affect Human Cognition&lt;/a&gt; (1400 ppm).&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2020-01-09T23:51:07.957" LastActivityDate="2020-01-09T23:51:07.957" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18886" PostTypeId="2" ParentId="18843" CreationDate="2020-01-05T22:46:13.873" Score="1" Body="&lt;p&gt;To add to the comprehensive answer on weather patterns, The weather and climate in Australia is affected by conditions in the oceans, particularly the equatorial Pacific Ocean and the Indian Ocean. These drive the major weather systems and their interactions affect the patterns over the continents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are good, layperson, introductions to the main weather drivers over &lt;a href=&quot;http://agriculture.vic.gov.au/agriculture/weather-and-climate/understanding-weather-and-climate/climatedogs#&quot; rel=&quot;nofollow noreferrer&quot;&gt;Victoria&lt;/a&gt; and &lt;a href=&quot;https://www.dpi.nsw.gov.au/climate-and-emergencies/seasonal-conditions/climatedogs&quot; rel=&quot;nofollow noreferrer&quot;&gt;New South Wales&lt;/a&gt; in eastern Australia&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2020-01-05T22:46:13.873" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18887" PostTypeId="2" ParentId="17725" CreationDate="2020-01-06T09:41:02.407" Score="9" Body="&lt;p&gt;The Russians did &quot;succeed&quot; to reach the water at borehole 5G-2 in 2012. However, the lake water flooded into the borehole due to overpressure, and refroze. They drilled again during the next campaign to sample this refrozen lake water, but found that it was contaminated by drilling fluid (DF). From &lt;a href=&quot;https://doi.org/10.1144/SP461.3&quot; rel=&quot;noreferrer&quot;&gt;Alekhina et al. 2017&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;As expected, the level of contamination of the frozen water core with the DF constituents decreases as the depth of sampling increases. However, even in sample 3450, the deepest and cleanest of all those studied, the concentration of foreign organic compounds (16.7 mg l−1) indicates significant chemical contamination, especially for water as pristine as that which we expected to obtain from Lake Vostok [...] After the rising water in borehole 5G-2 reached the junction of the two boreholes and continued to rise in 5G-1, the drilling fluid that remained trapped in the abandoned borehole began to be displaced by the heavier water. As a result, about 1 t of DF rose from the bottom of 5G-1 to the top of the lake water column that had already filled the borehole. During this process, the rising DF mixed with, and thus contaminated, the freezing water.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Because of this contamination, any biology result from these ice cores would be invalid for the scientific community. After that, the Russians have drilled a new borehole (5G-3) where they allegedly managed to sample pure, uncontaminated water in 2015 (here is the &lt;a href=&quot;https://www.rt.com/news/226127-lake-vostok-russia-water/&quot; rel=&quot;noreferrer&quot;&gt;press release from RT&lt;/a&gt;, which is &lt;em&gt;not&lt;/em&gt; considered a neutral source...). However, I could not find any published results from this sample. And the same year, &lt;a href=&quot;https://doi.org/10.1126/science.350.6260.494&quot; rel=&quot;noreferrer&quot;&gt;Russia cut Vostok project's budget&lt;/a&gt;... So I doubt we will see anything coming out of this in the future.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On a more positive note, scientists did manage to drill through 800 meters of Antarctica ice to reach another lake, lake Whillans, without contaminating it (they used only hot water to drill, not drilling fluid). And they did find &quot;a diverse assemblage of bacteria and archaea&quot;. From &lt;a href=&quot;https://doi.org/10.1038/nature13667&quot; rel=&quot;noreferrer&quot;&gt;Christner et al. 2014&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Our data show that SLW supports a metabolically active and phylogenetically diverse ecosystem that functions in the dark at sub-zero temperatures, confirming more than a decade of circumstantial evidence regarding the presence of life beneath Antarctica’s ice sheet [...] Given the prevalence of subglacial water in Antarctica, our data from SLW lead us to contend that aquatic microbial ecosystems are common features of the subsurface environment that exists beneath the ~10&lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{^7}$&lt;/span&gt; km&lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{^2}$&lt;/span&gt;/s Antarctic ice sheet.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, there is a major difference with lake Vostok: lake Whillans is connected to a hydrological system, while lake Vostok is &quot;closed&quot; and has a water residence time of over 10,000 years. So if life is trapped in there, it could have evolved differently...&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-01-06T09:41:02.407" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18888" PostTypeId="2" ParentId="18248" CreationDate="2020-01-06T11:17:14.230" Score="1" Body="&lt;p&gt;tl,dr: The direct effect of burning most of the fossil fuels (6 to 10°C temperature rise) may be survivable for some. But that does not take into account secondary effects triggered by the warming, like heat waves, ocean deoxygenation, flooding, melting of ice caps, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The study below is already a bit dated, latest research has shown that earlier projections were too optimistic, but here you go (paywalled):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1038/nclimate3036&quot; rel=&quot;nofollow noreferrer&quot;&gt;The climate response to five trillion tonnes of carbon&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The study assumes a linear response from the temperature rise to carbon emissions, until the end of the next century.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This would heat the earth's atmopshere by 6.5 to 9.5°C. So, this is a theoretical play with numbers (for now), the effects on complex life can only be imagined (anoxic ocean ?).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pop science discussions of it can be found here:&#xA;&lt;a href=&quot;https://phys.org/news/2016-05-fossil-fuels-earth.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;phys.org&lt;/a&gt;, &lt;a href=&quot;https://www.vice.com/en_us/article/zn8b84/new-climate-study-paints-bleakest-picture-of-our-future-to-date&quot; rel=&quot;nofollow noreferrer&quot;&gt;vice.com&lt;/a&gt;, &lt;a href=&quot;https://www.nationalgeographic.com/news/2016/05/160523-climate-change-study-eight-degrees/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NatGeo&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is not possible to say with confidence how much oxygen levels will fall. They &lt;a href=&quot;https://science.sciencemag.org/content/353/6306/1427&quot; rel=&quot;nofollow noreferrer&quot;&gt;did fall&lt;/a&gt; in the Pleistocene and today fall faster than CO2 rises. But that still does not account for the loss of ecosystems like forests and parts of the ocean becoming an oxygen sink. It is safe to say that this is not sustainable, it alone will not render the atmopshere unbreathable in the next 200 years, but in the &lt;a href=&quot;https://link.springer.com/article/10.1007/s12576-016-0501-0&quot; rel=&quot;nofollow noreferrer&quot;&gt;long run it will endanger our species&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, this should all be taken with the proverbial &lt;a href=&quot;https://www.canarias.com/blog/wp-content/uploads/2015/09/Salinas-Fuencaliente.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;grain of salt&lt;/a&gt; (local product :-)).&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-07T17:28:51.557" LastActivityDate="2020-01-07T17:28:51.557" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18889" PostTypeId="1" AcceptedAnswerId="18891" CreationDate="2020-01-06T12:45:45.257" Score="1" ViewCount="166" Body="&lt;p&gt;I would like to ask you about evaporation from sea water. Can you increase evaporation by spraying seawater to the air? Is there any difference compared to freshwater spraying (aerosol particles)? &lt;/p&gt;&#xA;" OwnerUserId="18631" LastActivityDate="2020-01-06T14:28:55.933" Title="Increase Evaporation from oceans" Tags="|meteorology|oceanography|water|climatology|evaporation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18890" PostTypeId="1" CreationDate="2020-01-06T13:45:41.413" Score="5" ViewCount="571" Body="&lt;p&gt;Most of the commonly mentioned effects of the ongoing and predicted climate change are negative: more extreme weather effects, more destructive weather, more diseases, rapid extinctions, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is this so?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is clear that &lt;em&gt;any rapid change&lt;/em&gt; brings many negative effects. We humans, as well as the biosphere, are adapted to the current conditions. Any sudden deviation from these conditions will take painful re-adaptation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But my impression is that several of the commonly mentioned negative effects go beyond than what can be explained by just &lt;em&gt;change&lt;/em&gt;. Is this really so?  If yes, would a cooling climate (beyond restoring pre-industrial conditions) bring more positive effects?&lt;/p&gt;&#xA;" OwnerUserId="18632" LastEditorUserId="6" LastEditDate="2020-01-06T16:56:11.990" LastActivityDate="2020-01-15T09:59:39.217" Title="Why are most effects of the predicted climate change negative?" Tags="|climate-change|" AnswerCount="4" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18891" PostTypeId="2" ParentId="18889" CreationDate="2020-01-06T14:28:55.933" Score="0" Body="&lt;p&gt;Yes, you can increase evaporation by spraying the sea water as an aerosol because this increases surface area. It's the same with fresh water too, but why would you want to do it? It wouldn't have any noticeable effect on the humidity of the general area. The only useful effect that I can see concerns fresh water only. Spraying the water from a pond or small lake as fine droplets would increase the oxygen content and benefit the fish. Hot weather depletes the oxygen in the water and sometimes fish become distressed, so if you want to save your valuable coy carp it might be a good idea. In the ocean it doesn't work, the sea is too vast.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-06T14:28:55.933" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18892" PostTypeId="1" CreationDate="2020-01-06T15:22:39.163" Score="4" ViewCount="343" Body="&lt;p&gt;Before the onset of modern style plate tectonics and the Wilson cycles in the &lt;a href=&quot;https://www.nature.com/articles/s41598-018-33823-y&quot; rel=&quot;nofollow noreferrer&quot;&gt;late Archean&lt;/a&gt;, it is thought that smaller units of continental crust, called &lt;a href=&quot;https://en.wikipedia.org/wiki/Craton&quot; rel=&quot;nofollow noreferrer&quot;&gt;cratons&lt;/a&gt;, roamed the oceanic crust over a more vigorously convecting mantle. These cratons already show &lt;a href=&quot;https://pubs.geoscienceworld.org/gsa/lithosphere/article/6/1/35/145696/Craton-formation-Internal-structure-inherited-from&quot; rel=&quot;nofollow noreferrer&quot;&gt;structures&lt;/a&gt; that suggest that they collided and accreted back in the day. Also, it is assumed that by the end of the Archean, 70% of today's crust had already been formed, though probably not at greater depths, and with a &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0016703719305009&quot; rel=&quot;nofollow noreferrer&quot;&gt;significant change&lt;/a&gt; around the time tectonics kicked in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Wikipedia article suggests 3 formation processes, but the cite link is broken.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;1) surface crust was thickened by a rising plume of deep molten material, 2) successive subducting plates of oceanic lithosphere became lodged beneath a proto-craton in an under-plating process, 3) accretion from island arcs or continental fragments rafting together to thicken into a craton&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My questions would be: Would uplift by a rising plume or underplating lift the originally basaltic material high enough for erosion to kick in and produce felsic/silicate/continental sediments, pre 2.5Gy ? Was the basement already solid enough to support the weight of mountains ? If i am not mistaken, todays exposed metamorphic old shields underwent low pressure metamorphosis of already felsic material. What do we know about the emplacement of the sediments from which they formed ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can easily split into several questions, no question.&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-06T21:04:03.177" LastActivityDate="2020-01-06T21:04:03.177" Title="Cratonization - how did the Archean cratons form?" Tags="|geophysics|plate-tectonics|models|earth-history|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18893" PostTypeId="2" ParentId="7913" CreationDate="2020-01-06T17:01:21.230" Score="5" Body="&lt;p&gt;There are lot of studies on the past activity of Mount Vesuvius. Eruptive deposits have been studied and dated in order to reconstruct the type and timing of past eruptions. This can give some indication of what to expect even if, and I cannot stress this enough, &lt;em&gt;past activity patterns of a given volcano do not predict its future activity&lt;/em&gt;. It can give a tendency, but volcanoes remain unpredictable, as shown by recent examples in well-monitored countries like Japan (&lt;a href=&quot;https://en.wikipedia.org/wiki/2014_Mount_Ontake_eruption&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mount Ontake 2014 eruption&lt;/a&gt;) or Italy (paroxysmal eruptions at Stromboli in summer 2019).&lt;/p&gt;&#xA;&lt;p&gt;That being said, a study by &lt;a href=&quot;https://doi.org/10.1016/j.jvolgeores.2008.04.024&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cioni et al. (2008)&lt;/a&gt; came up with some interesting results. They found that there is a positive correlation between the magnitude of an eruption and the repose time before this eruption, i.e., the longer we wait before an eruption of Vesuvius, the larger the eruption will be. It's their figure 6:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fK2el.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fK2el.jpg&quot; alt=&quot;Figure 6 from Cioni et al. 2008&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;You can see that Strombolian (= small) eruptions happen after a few years of repose while sub-Plinian and Plinian (= large, like the one that destroyed Pompei) eruptions are preceded by long repose periods. However there is some scattering, especially in the zone shown by a red box:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In particular, a large variability in the magnitude and eruption style of the past eruptions is apparent for a window of repose time from dozens to hundreds of years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;And now we are exactly in this box: the last eruption of Vesuvius was in 1944, 77 years ago. So according to this study, and &lt;em&gt;assuming the volcano will keep following this pattern&lt;/em&gt; (which is not sure), if Vesuvius does erupt tomorrow, it could be up to a violent Strombolian eruption. This type of eruption would not be a major threat to the local population; the main threat is pyroclastic density currents, which happen mostly with sub-Plinian and Plinian eruptions (their Table 2). The last eruption (1944) falls in the &amp;quot;violent Strombolian&amp;quot; category; lava flows destroyed several villages, but no one was killed.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2021-09-17T08:30:37.003" LastActivityDate="2021-09-17T08:30:37.003" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18894" PostTypeId="2" ParentId="7885" CreationDate="2020-01-06T19:10:21.557" Score="2" Body="&lt;p&gt;The Origin of the Sahara sand is still hotly debated among scientists (&lt;a href=&quot;https://www.researchgate.net/publication/278368495_Revisiting_the_age_of_the_Sahara_Desert&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/publication/278368495_Revisiting_the_age_of_the_Sahara_Desert&lt;/a&gt; ). Desert conditions in the Sahara have been redated from 86 M years to 300 M (&lt;a href=&quot;https://www.researchgate.net/publication/7053354_Revisiting_the_Age_of_the_Sahara_Desert&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/publication/7053354_Revisiting_the_Age_of_the_Sahara_Desert&lt;/a&gt; ). In any case, it is totally impossible to account for weathering in a few million years given the huge amount of sand (volume of 9.2 M km² x 42 m depth). It has recently been admitted that the Sahara turned into a desert pretty recently (5 thousand years ago) (&lt;a href=&quot;https://www.livescience.com/28493-when-sahara-desert-formed.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.livescience.com/28493-when-sahara-desert-formed.html&lt;/a&gt;) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then the origin of the sand cannot be established, although weathering has been discarded as a primary factor. Additionally, sand quartz crystals are covered in an iron coating that could only be done by raining or aereal deposition. Granite (main source of quartz) is not usually near the surface in the required quantities. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other conundrums are the several dozens of &quot;fossilized&quot; whales in Wadi Al-Hitan (near El Cairo). How have they been superficially buried (allegedly millions of years ago) if the desert formed 5000 years ago? (&lt;a href=&quot;https://peerj.com/articles/6381/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://peerj.com/articles/6381/&lt;/a&gt;)&#xA;On the contrary, if sand is due to millions of years of weathering, How was the Sphinx eroded by rain-off water as debated between Schoch and Reader (&lt;a href=&quot;http://ancientaliensdebunked.com/how-old-is-the-sphinx-colin-reader-vs-robert-schoch/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://ancientaliensdebunked.com/how-old-is-the-sphinx-colin-reader-vs-robert-schoch/&lt;/a&gt;), if there is no rain in the desert? &lt;/p&gt;&#xA;" OwnerUserId="18634" LastActivityDate="2020-01-06T19:10:21.557" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18895" PostTypeId="1" CreationDate="2020-01-06T21:14:28.290" Score="6" ViewCount="1623" Body="&lt;p&gt;The freezing point of carbon dioxide is -78.5 &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{^o}$&lt;/span&gt;C. Occasionally this low is exceeded in Antarctica, and small quantities of CO&lt;sub&gt;2&lt;/sub&gt; are frozen out, but are returned soon after to the atmosphere. Is it possible that during an ice age more substantial quantities of CO&lt;sub&gt;2&lt;/sub&gt; are frozen out, and could it be enough to affect the climate and worsen the ice age? Could this phenomenon also occur in Siberia?&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="2470" LastEditDate="2020-01-08T17:49:32.103" LastActivityDate="2020-01-08T17:49:32.103" Title="Are Ice Ages Affected by the Freezing Out of CO2 in Antarctica?" Tags="|co2|climatology|ice-age|antarctica|" AnswerCount="3" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="18896" PostTypeId="1" AcceptedAnswerId="18897" CreationDate="2020-01-07T04:32:15.913" Score="4" ViewCount="301" Body="&lt;p&gt;The Australian fires are the biggest anyone has ever seen and is increasing at a rapid rate causing smog all around the country, approximately &lt;a href=&quot;https://www.abc.net.au/news/2020-01-09/nsw-bushfires-kill-over-a-billion-animals-experts-say/11854836&quot; rel=&quot;nofollow noreferrer&quot;&gt;1 billion animals have lost their lives&lt;/a&gt;, as of 9 January 2020. The firefighters are rescuing people and animals and doing their best.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But How do you stop such a huge fire? I've heard of a way where in tons of sand are deployed through jets but fire at such a huge scale i wonder how that is gonna help.&lt;/p&gt;&#xA;" OwnerUserId="18633" LastEditorUserId="2470" LastEditDate="2020-01-09T06:36:38.637" LastActivityDate="2020-07-27T20:49:54.207" Title="How do you stop the Australian wildfires?" Tags="|planetary-science|wildfire|hazardous|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18897" PostTypeId="2" ParentId="18896" CreationDate="2020-01-07T07:08:16.597" Score="6" Body="&lt;p&gt;As of 7 January 2020, the total area burnt by the fires in the whole of Australia is &lt;a href=&quot;https://en.wikipedia.org/wiki/2019%E2%80%9320_Australian_bushfire_season&quot; rel=&quot;nofollow noreferrer&quot;&gt;8.4 million hectares (21 million acres; 84,000 square kilometres; 32,000 square miles&lt;/a&gt;. That is equivalent in area to the nations of &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_countries_and_dependencies_by_area&quot; rel=&quot;nofollow noreferrer&quot;&gt;Austria or the United Arab Emirates&lt;/a&gt;. Greater in area than the Czech Republic, Ireland or Sri Lanka.&lt;/p&gt;&#xA;&lt;p&gt;The vast majority of that has been on the eastern side of the country, in New South Wales (49,000 sq km) and Victoria (12,000 sq km). In Western Australia, the area has been 15,000 sq km and has forced the &lt;a href=&quot;https://www.abc.net.au/news/2020-01-01/road-closures-cause-nullarbor-travel-chaos/11836476&quot; rel=&quot;nofollow noreferrer&quot;&gt;closure of the southern road between east and west&lt;/a&gt; twice.&lt;/p&gt;&#xA;&lt;p&gt;With many fires burning in many areas the only course of action is to let the fires burn out by themselves. The efforts of fire fighting crews is to mainly protect areas from being burnt: properties and ecological regions of significance, such as the region containing &lt;a href=&quot;https://en.wikipedia.org/wiki/Wollemia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wollemi pines&lt;/a&gt; and other forested areas.&lt;/p&gt;&#xA;&lt;p&gt;Dumping sand, as you inquire about, has problems: from where to source the sand, the amount of sand required, how to dump the sand, will the dumped sand have a negative environmental impact afterwards.&lt;/p&gt;&#xA;&lt;p&gt;The fire fighting methods currently use in Australia are the same as with fire fighting practices for bush fires (wild fires) elsewhere. Fire are left to burn themselves out. The fringes of fires will be doused with water, either by ground crews and water trucks or via aerial bombardment, with water bombers (fixed winged aircraft or helicopters). Beating fire out is also used. Aerial bombardment will also include the used of fire retarding chemicals.&lt;/p&gt;&#xA;&lt;p&gt;To prevent fires from spreading, firebreaks are also made, where large areas of ground are cleared of flammable material to prevent them from being ignited by &lt;a href=&quot;https://en.wikipedia.org/wiki/Ember_attack&quot; rel=&quot;nofollow noreferrer&quot;&gt;ember attacks&lt;/a&gt;. This can also include the use of back burning, by fire crews, where forest is deliberately set alight by fire crews. This is only done when considered necessary and when weather conditions are favorable - wind directions and strength, humidity and temperatures.&lt;/p&gt;&#xA;&lt;p&gt;The trouble with bush fires in Australia is &lt;a href=&quot;https://en.wikipedia.org/wiki/Eucalyptus&quot; rel=&quot;nofollow noreferrer&quot;&gt;eucalyptus&lt;/a&gt; is a significant species of Australian forests.  Eucalyptus requires fire to regenerate. They also shed large quantities of leaves and bark that accumulate on forest floors. A controversial method of minimizing bush fires has been to burn forest deliberately in cooler periods, under more controlled conditions, to reduce the fuel load during the main summer fire season.&lt;/p&gt;&#xA;&lt;p&gt;By not letting the fires burn themselves out, the unburnt leaf and bark litter on the forest floors will remain and accumulate presenting another fire problem for the future.&lt;/p&gt;&#xA;&lt;p&gt;Australia will always burn, it's the nature of its forests. Bush fires are an expected, but unwelcome part of summer in Australia. What Australia needs is better forest fire management strategies.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;em&gt;Edit 28 July 2020&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Recent information about the Gosper's Mountain mega blaze that burnt more than one million hectares.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.abc.net.au/news/2020-07-27/gospers-mountain-mega-blaze-investigation/12472044?nw=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Anatomy of a 'mega blaze'&lt;/a&gt; - text and short videos of about the fire, from ignition by lightening strike, advance, merger with three other fires and how it was fought.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.abc.net.au/news/2020-07-28/gospers-mountain-mega-blaze-investigation-video/12494510&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gosper's Hill 'mega blaze'&lt;/a&gt;, a 13 minute long video.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2020-07-27T20:49:54.207" LastActivityDate="2020-07-27T20:49:54.207" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18898" PostTypeId="2" ParentId="18895" CreationDate="2020-01-07T07:29:24.410" Score="3" Body="&lt;p&gt;During an ice age little CO2 will reach the arctic,it will be absorbed by sea water in all the oceans,This will create a positive feedback,lower CO2 level in the atmosphere will make it even colder so the liquid water will absorb even more CO2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cold water can hold large amounts of dissolved gasses,When the ice age ends large amounts of CO2 will be released creating a positive feedback loop further increasing the heating.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the problems with the climate change we see now is that the oceans are getting hotter,This will lower the waters capacity to absorb CO2 from the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At some point if the heating goes on the ocean water might start releasing more CO2 than it absorbs.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6258" LastEditDate="2020-01-08T13:07:23.510" LastActivityDate="2020-01-08T13:07:23.510" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18899" PostTypeId="1" CreationDate="2020-01-07T10:06:45.320" Score="16" ViewCount="4731" Body="&lt;p&gt;Saturday 4th January was truly an extroadinary and terrible day for the south-east corner of Australia. Skies turned pitch black at around 3-5 pm, when normally these areas would be in daylight. I have never been aware of this sort of phenomenon. Is it possible that thick smoke alone could have caused this, or was it larger particles such as burnt leaves and bark, picked up by strong updraughts from pyrocumulus clouds? It is worth noting that this occurred right before a cold front passed through the area, bringing southerly winds, and that pyrocumulus clouds had formed, and lightning was being generated from them.&lt;/p&gt;&#xA;" OwnerUserId="18636" LastActivityDate="2020-01-08T10:14:58.267" Title="Why did the Australian bushfires cause pitch darkness during the daytime?" Tags="|wildfire|fire|" AnswerCount="3" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18900" PostTypeId="2" ParentId="18899" CreationDate="2020-01-07T11:17:17.477" Score="12" Body="&lt;p&gt;It's a combination of both the density and amount of smoke in the air and &lt;a href=&quot;https://www.theguardian.com/australia-news/2020/jan/04/australia-bushfires-week-of-anger-scott-morrison&quot; rel=&quot;noreferrer&quot;&gt;ash&lt;/a&gt; produced by the fire.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The thing about &lt;a href=&quot;https://mobile.abc.net.au/news/2019-11-11/fire-weather-and-why-tuesday-looks-so-bad/11693894?pfmredir=sm&quot; rel=&quot;noreferrer&quot;&gt;cold fronts and bush fires&lt;/a&gt; is they make the conditions for fire worse by pushing hot air in front of them. They have been blamed for the severity of the bush fires in Victoria in 2009, 1983 and 1939.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2020-01-07T11:27:51.570" LastActivityDate="2020-01-07T11:27:51.570" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18901" PostTypeId="2" ParentId="18899" CreationDate="2020-01-07T11:17:34.233" Score="2" Body="&lt;p&gt;It was a combination of thick smoke and pyrocumulus clouds. Possibly there might have been other types of cloud as well, Ash rising on the updraught may also have been a factor. I am informed that normal types of cloud sometimes made an appearance during the drought. Near-pitch darkness in daylight hours is also characteristic of volcanic eruptions, but I am not suggesting that volcanic eruptions were a factor in this case, though they make an analogy. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;During cumulonimbus events in England, usually accompanied by rain and thunder, we often get very dim light in mid afternoon, long before evening time, though I wouldn't describe it as pitch darkness but more a sort of twilight. If enormous plumes of smoke were added, it very likely would have become almost pitch dark.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-07T11:17:34.233" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18902" PostTypeId="2" ParentId="18895" CreationDate="2020-01-07T11:20:58.600" Score="5" Body="&lt;p&gt;-98°C is as cold as it can get on Earth, in isolated places, where air and surface radiation are in equlibirum in the polar winter and no exchange happens &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018GL078133&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scambos et al 2018&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given the low atmopsheric CO2 in cold phases, &lt;a href=&quot;https://www.climate.gov/news-features/features/antarctica-colder-arctic-it%E2%80%99s-still-losing-ice&quot; rel=&quot;nofollow noreferrer&quot;&gt;extremely low precipitation&lt;/a&gt; rates and an &lt;a href=&quot;http://www.ccpo.odu.edu/SEES/ozone/class/Chap_11/11_3.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;isolating polar vortex&lt;/a&gt; around Antarctica and no isotopic signal in cores it can be doubted that the physical conditions for large scale &#xA;frozen phases of CO2 were met at any time in the Pleistocene.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are two papers that deal with modelling global mean temperatures in the Cryogenian: &lt;a href=&quot;https://advances.sciencemag.org/content/3/11/e1600983.full&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hoffman et al 2017&lt;/a&gt; and &lt;a href=&quot;https://pure.mpg.de/rest/items/item_993585_4/component/file_993584/content&quot; rel=&quot;nofollow noreferrer&quot;&gt;Voight at al 2011&lt;/a&gt;. Global cooling is only estimated to a few °C (3 and 4.6). Otoh, others suggests a global  mean temperature of -12°C. But that lacks proper citing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whether such an extreme case as today's Antarctica with altitudes of &gt;4000m (that's closer to space in the cold, dense air than it sounds) and its isolation from the global circulation existed back then, that is unclear.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Citing from Hoffman et al:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;However, an ice-covered planet with Earth-like obliquity and distance (1 astronomical unit) from a Sun-like star, with or without CO2 ice clouds, remains far below the threshold for CO2 ice deposition at any CO2 level relevant to a Cryogenian Snowball Earth [see figure 2b and c in the study by Turbet et al. (70)]. The risk of irreversibility due to CO2-ice deposition is not so easily dismissed for a Siderian (2.4 Ga) Snowball Earth (Fig. 2B), when the Sun was about 10% dimmer than in the Cryogenian.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, not in the Cryogenian glaciation(s), clearly not afterwards, but maybe before, what they call Siderian (may also be known as the Huronian(?) glaciation) may CO2 ice have hypothetically been deposited on earth. The problem with such a CO2 burial is that it sinks gravitationally into the water ice and is thus removed from the circulation, potentially leading to an unescapable snowball state &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0012821X17304363&quot; rel=&quot;nofollow noreferrer&quot;&gt;Turbet et al 2017&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-07T20:00:34.223" LastActivityDate="2020-01-07T20:00:34.223" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18903" PostTypeId="2" ParentId="18895" CreationDate="2020-01-07T13:46:00.120" Score="9" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The freezing point of carbon dioxide is -78.5C.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The temperature at which carbon dioxide sublimates is not a fixed value. It instead is a function of the partial pressure of carbon dioxide. That value of -78.5° C is the temperature at which CO&lt;sub&gt;2&lt;/sub&gt; sublimates given a partial CO&lt;sub&gt;2&lt;/sub&gt; pressure of one atmosphere. The temperature needed to have CO&lt;sub&gt;2&lt;/sub&gt; sublimate given a partial pressure of 40 pascals is much lower than that.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Clausius%E2%80%93Clapeyron_relation&quot; rel=&quot;noreferrer&quot;&gt;Clausius-Clayperon relation&lt;/a&gt; can be used to estimate the temperature at which a substance will sublimate for a given partial pressure. Using the parameter values for CO&lt;sub&gt;2&lt;/sub&gt; from James et al., I get a temperature of &lt;a href=&quot;https://www.wolframalpha.com/input/?i=3182.48%2F%2823.3494+-+ln%280.4%29%29&quot; rel=&quot;noreferrer&quot;&gt;131 kelvins&lt;/a&gt; (-142° C) for the sublimation point of CO&lt;sub&gt;2&lt;/sub&gt; at a partial pressure of 40 pascals or 0.4 millibar. Using a slightly different parameterization, Agee et al. calculate that a temperature of 133 kelvins (-140° C) is needed to make CO&lt;sub&gt;2&lt;/sub&gt; sublimate from our atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Are Ice Ages Affected by the Freezing Out of CO2 in Antarctica?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Carbon dioxide levels are very low during glaciations (colloquially, ice ages, but we're in an ice age right now). Using the parameterization from James et al. yields a temperature of 127 K (-146° C) as the sublimation temperature for a partial pressure of 18 Pa (0.18 millibar), or 180 ppm CO&lt;sub&gt;2&lt;/sub&gt;. The Earth cannot get that cold, so no, ice ages are not affected by the freezing out of CO&lt;sub&gt;2&lt;/sub&gt; in Antarctica.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Agee, Ernest, Andrea Orton, and John Rogers. &quot;CO2 snow deposition in Antarctica to curtail anthropogenic global warming.&quot; Journal of Applied Meteorology and Climatology 52.2 (2013): 281-288.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;James, Philip B., Hugh H. Kieffer, and David A. Paige. &quot;The seasonal cycle of carbon dioxide on Mars.&quot; Mars (1992): 934-968.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2020-01-07T14:11:16.117" LastActivityDate="2020-01-07T14:11:16.117" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18904" PostTypeId="2" ParentId="8327" CreationDate="2020-01-07T14:16:02.453" Score="1" Body="&lt;p&gt;For magma and lava it's liked you said: &quot;magma&quot; is used under the surface, &quot;lava&quot; above. See for instance &lt;a href=&quot;https://volcanoes.usgs.gov/vsc/glossary/lava.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;the definition of USGS Volcano Hazard Program's glossary&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Lava&lt;/strong&gt;: General term for magma (molten rock) that has been erupted onto the surface of the Earth and maintains its integrity as a fluid or viscous mass, rather than exploding into fragments.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Now, does this simple location change justify another term? I would argue that yes, for this reason: &lt;strong&gt;if all lavas have once been magmas, all magmas will not become lava&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fate of magmas can vary. Some will form plutons and crystallize inside the crust instead of reaching the surface. Granites, for instance, have once been magmas. This is why the main rock type &quot;magmatic rocks&quot; is subdivided into two subcategories: plutonic rocks and volcanic rocks. Even in the volcanic subcategory, all rocks are not lavas. As the USGS definition suggests, only a magma erupted effusively becomes a lava. A magma erupted explosively generates another type of volcanic rocks: &lt;a href=&quot;https://volcanoes.usgs.gov/vsc/glossary/tephra.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;tephra&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-01-07T14:16:02.453" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18905" PostTypeId="2" ParentId="8327" CreationDate="2020-01-07T15:35:28.180" Score="1" Body="&lt;p&gt;And it is similarly just a naming convention with the meteor* things:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://spaceplace.nasa.gov/asteroid-or-meteor/en/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://spaceplace.nasa.gov/asteroid-or-meteor/en/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://solarsystem.nasa.gov/asteroids-comets-and-meteors/meteors-and-meteorites/in-depth/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://solarsystem.nasa.gov/asteroids-comets-and-meteors/meteors-and-meteorites/in-depth/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regardless of its composition, when it breaks off from an asteroid or comet, as long as it is in space it is a meteoroid. When it hits the atmosphere, it turns into a meteor, and when it is lying on the ground ready to be taken home or elsewhere and classified by composition, it has converted into a meteorite.&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-07T15:52:12.080" LastActivityDate="2020-01-07T15:52:12.080" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18907" PostTypeId="2" ParentId="18878" CreationDate="2020-01-07T17:26:22.690" Score="1" Body="&lt;p&gt;I make no claim to be an expert on Venus, and I welcome correction from those who are, but I think there's a misunderstanding in the question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Venus... won't let any of the heat absorbed from the Sun out by radiation&quot; is false. It must be, due to fairly fundamental physical laws.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, I'm not sure whether any energy emitted from the &lt;em&gt;surface&lt;/em&gt; of Venus reaches space. I imagine that some fraction probably does, but I could be wrong - it could be that the atmosphere is entirely opaque to the wavelengths radiated from the ground. However, the atmosphere itself is warm, and hence the atmosphere itself radiates, partly into space. This is different to the way things mostly work on Earth, where the atmosphere is mostly (but decreasingly) transparent to the wavelengths radiated from the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At least on short timescales, then, there's a balance between incoming and outgoing energy, and Venus is in equilibrium. It won't keep getting warmer forever, unless something changes to change the temperature of that equilibrium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By analogy, Earth was in equilibrium until the industrial revolution. Since then things have been increasingly disrupted by a massive increase in greenhouse gas concentrations. Once we stop increasing GHG concentrations, it will warm until it reaches a new equilibrium at a higher temperature and then stop. It won't keep getting warmer forever.&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="39" LastEditDate="2020-01-10T07:26:51.133" LastActivityDate="2020-01-10T07:26:51.133" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18908" PostTypeId="2" ParentId="18890" CreationDate="2020-01-07T18:20:23.693" Score="1" Body="&lt;p&gt;I don't think there are any effects of climate change, which can be said to be particularly positive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The level of CO2 in the atmosphere we're currently experiencing has not been seen on earth for about 800,000 years &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_SPM_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC AR5&lt;/a&gt; and the consequences of this change in radiative forcing are massive. Particularly as we've engineered this change in the last 150 years or so (ridiculously fast as far as natural systems are concerned). The change is extremely large in magnitude and speed - and this is going to have a huge impact - so I think you're right in that pretty much any change is bad change. My best shot at some positive human results are&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) an ice-free northwest passage round the top of Canada and&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) a marginal improvement in the UK for agriculture&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are of course completely outweighed by the other costs - in both human and natural systems. &lt;/p&gt;&#xA;" OwnerUserId="18621" LastActivityDate="2020-01-07T18:20:23.693" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18909" PostTypeId="2" ParentId="18899" CreationDate="2020-01-08T10:14:58.267" Score="1" Body="&lt;p&gt;If you think how white smoke looks when it is rising elsewhere and you are looking at sunlight reflecting off it ... what you are then seeing, is some of the  light that the folks who have that smoke between them and the sun are not getting. Smoke will also absorb a lot of sunlight (and re-radiate it as infra-red), especially if it's sooty black smoke rather than whitish ash.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On a gloomy note, you are experiencing what a nuclear war would cause on a global scale (a nuclear winter, caused by the ashes of civilisation). At least your smoke is not radioactive and relatively short-term ....&lt;/p&gt;&#xA;" OwnerUserId="18495" LastActivityDate="2020-01-08T10:14:58.267" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18910" PostTypeId="2" ParentId="17876" CreationDate="2020-01-08T14:05:52.563" Score="3" Body="&lt;p&gt;(tl, dr at the end, the answer by user user18411 is mine from a former life on this site)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Addressing @MichaelWalsby's answer that contains numerous false claims and severe misunderstandings and lacks citing:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Forty years ago, protein electrophoresis and other molecular types of dating were pointing to a date of 4.5 million years for the separation of the hominid line from the pongid (great ape) line&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Firstly, humans never seperated from the hominid line. They are a part of it. The stricter term &quot;hominin&quot; comprises the human clade (visit Wikipedia). The mentioned work at that time 40 years ago must be cited in order to count as a proof. I have no idea what you mean.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;We now have Ardipithecus kadabba, dated at 6 million years BP, and Sahelanthropus tchadensis at 7 million years BP. These were bipedal hominids which had already split off from the common ancestor of the pongid line which led to modern chimps and gorillas. These early hominids were australopithecine-type creatures, small brained and still essentially bipedal apes, but having many characteristics similar to humans.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The mentioned &lt;a href=&quot;https://en.wikipedia.org/wiki/Ardipithecus_kadabba&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ardipithecus kaddaba&lt;/a&gt; plays not really a role, given the sparse remains. Generally claiming bipedalism for them is nonsense, maybe &quot;facultatively bidedal&quot;, but less than &lt;a href=&quot;https://en.wikipedia.org/wiki/Ardipithecus&quot; rel=&quot;nofollow noreferrer&quot;&gt;later hominins&lt;/a&gt; and it is debated because the only evidence (&lt;a href=&quot;http://projects.leadr.msu.edu/hominidfossils/exhibits/show/pre-australopiths/ardipithecus-kadabba&quot; rel=&quot;nofollow noreferrer&quot;&gt;a toe bone&lt;/a&gt;) does not belong to the found specimen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Australopithecine&quot; rel=&quot;nofollow noreferrer&quot;&gt;Austrolopithecines&lt;/a&gt; are not a homogenuous clade as the post implies. They split into the graciles (e.g. &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2842428/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Laetoli&lt;/a&gt;, here clear bipedalism but 2My after the Ardipithecus) and robust ones (e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Paranthropus&quot; rel=&quot;nofollow noreferrer&quot;&gt;Paranthropus&lt;/a&gt;), that actually follow the gracile ones in time by more than a million years. Gracilty and robustness (watch the dentition !) are a pretty strong hint to the life style, but that's another story.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sahelanthropus tchadensis is depicted as being bipedal, which is &lt;a href=&quot;http://www.bradshawfoundation.com/origins/sahelanthropus_tchadensis.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;incorrect&lt;/a&gt;. The evidence is far too weak to tell with certainty. But its role as a possible common ancestor of the humans and chimps should be mentioned !&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... but it is generally held that the first human was Homo habilis from Lake Turkana, Kenya ...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That is misleading. When speaking of Homo habilis (I had a professor whose last name was Bolus. We dubbed him Homo hobolus :-)) we generally refer to &lt;a href=&quot;https://en.wikipedia.org/wiki/KNM-ER_1805&quot; rel=&quot;nofollow noreferrer&quot;&gt;Koobi&lt;/a&gt; &lt;a href=&quot;https://en.wikipedia.org/wiki/KNM-ER_1813&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fora&lt;/a&gt;. Though it is Lake Turkana as well, we refer to &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Turkana_Boy&quot; rel=&quot;nofollow noreferrer&quot;&gt;Turkana boy&lt;/a&gt;&quot; as a nearly complete Homo erectus skeleton.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;All the most important hominid fossils were found in Africa, mainly East Africa.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is nonsense. Very important fossils come from Europe, e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Dmanisi#Archaeological_site&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dmanisi&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Archaeological_site_of_Atapuerca#Sima_de_los_Huesos_(1983_to_present)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atapuerca&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Tautavel_Man&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tautavel&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Sch%C3%B6ningen_spears&quot; rel=&quot;nofollow noreferrer&quot;&gt;Schöningen&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Mauer_1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mauer&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Steinheim_skull&quot; rel=&quot;nofollow noreferrer&quot;&gt;Steinheim&lt;/a&gt;, no Neandertals are known from Africa but hundreds from elsewhere today and there a huge number of Middle and Upper Paleolithic sites all over Europe and parts of Asia, enough for a chronology from Homo erectus all the way to today, that has not been done in that granularity in Africa yet. Important modern human sites are from south Africa, Morocco and the Levant, not from east Africa.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Palaeolithic, Mesolithic and Neolithic periods refer to the type of stone tools used by hominids at the relevant times. Palaeolithic tools were very primitive, and it usually takes an expert eye to identify them as tools rather than random fragments. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No. These expressions refer to a type of subsistence. Stone tools are used for finer classification. Pal. tools (middle and upper) were sophisticated to a degree that today only few (if at all) can replicate. Blade production in the upper pal. guarantees a high degree of standardization and reproducibility. Consider insets for composite tools like spears, if one breaks out it can easly be replaced, and much more. A tool is defined by its form, not by its use. But that leads too far, ask if you need more. But please be specific, like a time and a region, or else you send me away for days ...&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;They date from about the time of Homo habilis&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Nonsense. They date from a time from 2.6My to the Upper-, End-, Epipaleothic (~10,000BP), whichever is encountered in an area. No industry is connected to Homo habilis because there is no clear association. But there are associations with Homo erectus (e.g. Acheulien), Neandertals (e.g. Mousterien, Micoquien, Levallois-technique, Chatelperronien, ...) and modern humans (uncounted, see answer below for a selection).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It is entirely possible that some of these tools were made by Australopithecines.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There is no such (undebated) evidence, to date. But i will not apodictically exclude it for the future.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;and Neolithic tools were made comparatively recently by Homo sapiens and Homo neanderthalensis.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This deserves the term post factual piffle. The Neandertals were gone since more than 20,000 years when the Neolithic started. You, sir, have clearly no idea what a Neandertal or the Neolithic is ! Neandertal extinction happened around &lt;a href=&quot;https://www.nature.com/articles/s41467-019-12862-7&quot; rel=&quot;nofollow noreferrer&quot;&gt;40kyBP&lt;/a&gt; (some say 30), &lt;a href=&quot;https://en.wikipedia.org/wiki/Neolithic&quot; rel=&quot;nofollow noreferrer&quot;&gt;Neolithic&lt;/a&gt; emerged around 10,000BP.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Great Pyramid was built in the copper age&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Copper age is not an archeological term. We say Chalcolithic for a fully developed Neolithic with the use of copper. Those where the people who built the pyramids.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;which preceded the bronze age&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It did not. While bronze was in use in the Levant, Aegean, little Asia, Egypt stayed with copper (apart from isolated finds) until ~1600BC. That's not far from the introduction of iron. Call me for proof.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The 200,000 - 300,000-year dates you refer to are the approximate dates of the earliest Neanderthals and the migration of the first Homo sapiens from Africa into the Middle East and Asia&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Piffle. Just see Dmanisi, Tautavel, Atapuerca. But &gt;300,000 is the time when the first anatomically modern humans might have roamed parts of Africa (see the other answer for find sites).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;tl, dr and to answer the question:&#xA;First humans that undebatedly produced stone tools emerge ~2.6My ago. Those where unspecified erectusses if you don't split too much (i don't). The stone tool industry is called Olduvan or Oldovan (Wikipedia has Oldowan is see, it's Olduvai gorge that gave the name). The first anatomically modern humans arose ~300,000 to 350,000 BP. Oldest find sites in the other answer. An exact location cannot be named, for now, but Africa it was.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Before humans lived other hominid species who did not leave clear remains and traces of tool use behind. Note that tool use may have different definitions. For human tools use, it is not just grabbing a thing from the environment and dang it. A tool must show a cognitive process, a plan of shaping it into a form, and it is the form that defines a tool, not the use.&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-08T19:28:47.530" LastActivityDate="2020-01-08T19:28:47.530" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18911" PostTypeId="2" ParentId="14259" CreationDate="2020-01-08T14:55:48.980" Score="7" Body="&lt;h4&gt;Original answer&lt;/h4&gt;&#xA;&lt;p&gt;I think we can confidently enough answer &amp;quot;no&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;From the report &amp;quot;Eruptions of Hawaiian Volcanoes—Past, Present, and Future&amp;quot; &lt;a href=&quot;https://pubs.usgs.gov/gip/117/&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Tilling et al. 2010)&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Kilauea eruptions occur either at its summit or within two well-defined swaths (called rift zones) that radiate from the summit.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In the same report, you can see those rift zones on the map page 3, or on the sketch of the plumbing system page 24. Most lava flows are emplaced along these rift zones. For instance, look at this &lt;a href=&quot;https://volcanoes.usgs.gov/volcanoes/kilauea/geo_hist_1955.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;map of the 1955 eruption&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5ePiC.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5ePiC.jpg&quot; alt=&quot;Vents and lava flows from the Kilauea eruption of 1955&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Vents and lava flows from the Kīlauea eruption of 1955 superimposed on a USGS topographic map of the lower Puna region. (Credit: Trusdell, Frank. Public domain.)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You can see that the flows were emplaced in a zone very similar to the 2018 eruption. Apparently the power plant opened in 1993, and the first exploratory wells were drilled in 1961—62, so after this event.&lt;/p&gt;&#xA;&lt;p&gt;Actually, the rift zones are in the &lt;a href=&quot;https://pubs.usgs.gov/mf/1992/2193/&quot; rel=&quot;nofollow noreferrer&quot;&gt;lava flow hazard zone 1&lt;/a&gt;, i.e., the most severe. The zone is defined as follow by &lt;a href=&quot;https://pubs.usgs.gov/pp/1987/1350/pdf/chapters/pp1350_ch22.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mullineaux et al. (1987)&lt;/a&gt; (emphasis added):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Zone 1 consists of the summit areas and active parts of the rift zones of Kilauea and Mauna Loa; in those areas, 25 percent or more of the land surface has been covered by lava within historical time, during the 19th and 20th centuries. These areas contain the sites of most historical eruptions, and &lt;em&gt;a large majority of the lava flows that will affect other zones on Kilauea and Mauna Loa in the near future probably will originate in zone 1.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So the real question is: why was the plant (and estates...) built in an area well known for lava flow hazards?!&lt;/p&gt;&#xA;&lt;p&gt;To conclude, by researching the plant I found that it is actually where people accidentally drilled through a magma pocket for the first time (&lt;a href=&quot;http://pubs.geothermal-library.org/lib/grc/1028595.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Teplow et al. 2009&lt;/a&gt;)! They hit a pocket of dacite; it did not trigger an eruption. This happened later &lt;a href=&quot;https://en.wikipedia.org/wiki/Iceland_Deep_Drilling_Project#First_Well,_IDDP-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;in Iceland&lt;/a&gt;: this time, they even used it as an experimental well (there is &lt;a href=&quot;https://www.sciencedirect.com/journal/geothermics/vol/49&quot; rel=&quot;nofollow noreferrer&quot;&gt;a whole issue of Geothermics&lt;/a&gt; on this). Again, no eruption.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;h4&gt;October 2021 Update&lt;/h4&gt;&#xA;&lt;p&gt;I just came upon a USGS report called &amp;quot;Have Humans Influenced Volcanic Activity on the Lower East Rift Zone of Kīlauea Volcano? A Publication Review&amp;quot; (&lt;a href=&quot;https://doi.org/10.3133/ofr20201017&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kauahikaua and Trusdell 2020&lt;/a&gt;), which asks (and answers) exactly the same question:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Questions about the relation between human activity or developments and active Hawaiian volcanoes usually are raised during eruptions. These concerns often regard the location of an industrial development, like a geothermal power generation facility, on a volcano (for example, Big Island Video News, 2019; Firozi, 2018). Since the 2018 eruption, the topic of whether commercial developments not only caused the eruption to occur in Kīlaueaʻs lower East Rift Zone (LERZ), but also caused it to erupt with a higher-than-normal rate has been a subject of public discussion.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;They examined the past activity of the volcano (location, volume, frequency... of past eruptions), and compared it to the 2018 eruption, concluding (emphasis added):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;em&gt;There are no obvious effects of human activity on eruptions of Kīlauea volcano&lt;/em&gt;. There have been no significant changes due to human activity in patterns or trends of deformation or seismicity in the lower East Rift Zone in the last 35–50 years (before and during geothermal operations). The frequency and intensity of eruptions are variable, but it would be difficult to demonstrate a definitive change due to human activity. [...] &lt;em&gt;We find no evidence to support claims that human activity triggered or influenced the 2018 lower East Rift Zone eruption&lt;/em&gt;. The 2018 eruption was caused by injection of magma downrift from Puʻu ʻŌʻō and the summit of Kīlauea. The event fits a pattern of activity that has occurred many times previously on the East Rift Zone and is within the range of normal behavior for Kīlauea Volcano.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So again the answer is &amp;quot;no&amp;quot;, but the USGS is a source a bit more authoritative than me! :)&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2021-10-08T12:57:56.393" LastActivityDate="2021-10-08T12:57:56.393" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18912" PostTypeId="1" CreationDate="2020-01-08T17:55:22.270" Score="3" ViewCount="33" Body="&lt;p&gt;This image shows the Nowcasting Satellite Application Facility (NWCSAF) Cloud Liquid Water Path (LWP) product for 2020-01-08T12:00:00Z:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BsIDN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BsIDN.jpg&quot; alt=&quot;Cloud Liquid Water Path from NWCSAF&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;Cloud LWP from NWCSAF.  &lt;a href=&quot;http://www.nwcsaf.org/cmic2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source: NWCSAF&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;http://www.nwcsaf.org/Downloads/GEO/2018/Documents/Scientific_Docs/NWC-CDOP2-GEO-MFL-SCI-ATBD-Cloud_v2.1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Algorithm Theoretical Baseline Document&lt;/a&gt; (ATBD; PDF, 5.9 MB) divides the full disc into the illumination regimes night, twilight, and daytime by their solar elevation, defining daylight as a solar elevation of larger than 10° (ATBD, Table 3 on Page 14).  In the same document, §5.2.1.2.4 describes products only calculated in daytime conditions, including the LWP pictured above.  But in the image, the retrieval appears to only include elevation angles larger than around 20° (at noon UTC, near the prime meridian, it reaches about 48°N).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why do the data appear not to extend to solar elevation angles down to 10° such as documented, but rather truncate at around 20°?&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2020-01-08T17:55:22.270" Title="Why are Nowcasting SAF daytime products apparently truncated at solar angles of 20° (rather than the documented 10°)?" Tags="|clouds|earth-observation|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18914" PostTypeId="1" CreationDate="2020-01-08T20:22:13.410" Score="5" ViewCount="684" Body="&lt;p&gt;I am trying to estimate cloudbase height using calculations from my weather station temperature/humidity, by calculating those two variables I can get estimated cloudbase height but what puzzles me now is inversion layers and temperature at different heights. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know grib and grib2 files contain those data but I can't seem to figure out how to pull that data in Java even though I tried like every possible library. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any other way I can accurately estimate cloudbase levels by using some API which gives temperature by height for given latitude and longitude.&lt;/p&gt;&#xA;" OwnerUserId="18646" LastEditorUserId="2470" LastEditDate="2020-01-09T06:39:31.490" LastActivityDate="2020-01-09T17:22:08.797" Title="Estimate cloudbase height" Tags="|clouds|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18915" PostTypeId="2" ParentId="18914" CreationDate="2020-01-08T20:31:18.100" Score="4" Body="&lt;p&gt;From atmospheric soundings. For my area:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://weather.uwyo.edu/cgi-bin/sounding?TYPE=GIF%3ASTUVE&amp;amp;TIME=current&amp;amp;STNM=60018&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://weather.uwyo.edu/cgi-bin/sounding?TYPE=GIF%3ASTUVE&amp;amp;TIME=current&amp;amp;STNM=60018&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Selection from map:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://weather.uwyo.edu/upperair/sounding.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://weather.uwyo.edu/upperair/sounding.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A how-tos:&#xA;&lt;a href=&quot;http://www.csun.edu/~hmc60533/CSUN_103/weather_exercises/soundings/smog_and_inversions/Understanding%20Stuve_v3.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.csun.edu/~hmc60533/CSUN_103/weather_exercises/soundings/smog_and_inversions/Understanding%20Stuve_v3.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.eoas.ubc.ca/courses/atsc201/A201Resources/SoundingTutorial1/SoundingTutorial1Readings.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.eoas.ubc.ca/courses/atsc201/A201Resources/SoundingTutorial1/SoundingTutorial1Readings.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Search &quot;Lifting condensation level stüve (or stuve) diagram&quot;. The LCL is the level at which a rising package condensates, aka cloud base.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I once had to learn them, but i largely forgot the details, please don't corner me :-) And maybe there are more modern techniques.&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-08T20:38:36.070" LastActivityDate="2020-01-08T20:38:36.070" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18916" PostTypeId="2" ParentId="18914" CreationDate="2020-01-08T20:37:53.817" Score="7" Body="&lt;p&gt;You are right, you can't get cloudbase height without 3D data. You can do that using radiosondes. However, if your weather station has a &lt;a href=&quot;https://en.wikipedia.org/wiki/Ceilometer&quot; rel=&quot;nofollow noreferrer&quot;&gt;ceilometer&lt;/a&gt;, then you don't actually need many calculations. However, they are usually quite expensive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want a real rough calculation, you can just use the &lt;a href=&quot;https://en.wikipedia.org/wiki/Lifted_condensation_level&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lifted Condensation Level&lt;/a&gt;, which is more valid estimate during the day than at night.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note on the grib files: They may not always have all of the variables. For example, the WAVE ocean model (see &lt;a href=&quot;https://nomads.ncep.noaa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCEP NOMADS&lt;/a&gt;) won't have cloud base, because it is in fact for oceans. However, what you can do is use models like the &lt;a href=&quot;https://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/&quot; rel=&quot;nofollow noreferrer&quot;&gt;GFS&lt;/a&gt;, which tell you what model levels have clouds, and then find the height of the lowest level that has cloud cover. It will take some programming though.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2020-01-09T17:22:08.797" LastActivityDate="2020-01-09T17:22:08.797" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18917" PostTypeId="2" ParentId="2433" CreationDate="2020-01-09T09:55:26.607" Score="5" Body="&lt;p&gt;This is a lava &lt;a href=&quot;https://volcanoes.usgs.gov/vsc/glossary/tumulus.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;tumulus&lt;/a&gt;. Tumuli are a very common feature in pahoehoe lava flow fields. There is a classic paper by &lt;a href=&quot;https://doi.org/10.1007/BF00298155&quot; rel=&quot;nofollow noreferrer&quot;&gt;Walker (1991)&lt;/a&gt; describing their morphological characteristics and formation process. Here is an image from the article, you can see that it is almost identical to your photo:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AwZd7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AwZd7.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Tumulus B20, 2.8 m high, near Holei sea arch on south side of Kilauea.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Tumuli are formed by inflation of the cold, stationary crust which is lifted upwards by the influx of new lava underneath. From what I see on satellite images, they are common around Hveravellir.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2021-11-08T15:08:12.460" LastActivityDate="2021-11-08T15:08:12.460" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18918" PostTypeId="1" CreationDate="2020-01-09T15:25:44.670" Score="6" ViewCount="7079" Body="&lt;p&gt;I have been reading the discussion about pumping sea water into the desert for purposes of irrigation and changing the dry climate of that area, but what about to just purely offset the rising sea levels? Could pumping ocean water (with solar power) north of Malibu California into the dry areas help with coastline erosion and put water into the desert as a secondary but not primary benefit?&#xA;I am a completely non-scientific person who just happens to have an interest in coastal erosion so I welcome all your educated thoughts on this. Ideally it would be done in all the deserts globally to have a coordinated effort. Think of the infrastructure jobs in places like Africa. It would require a “world bank” initiative to create the funds to do this but as a global coordinated effort it may be required as part of planet rehabilitation. Yes I said “create” the funds, ie “print money” which would have a slightly inflationary effect on world economies but would mostly “inflate” depressed economies through wealth redistribution since these economies would likely be the major supply of labor. Like we see in Canada when the people from poor fishing towns went to work on the pipelines and brought cash back home. &lt;/p&gt;&#xA;" OwnerUserId="18650" LastEditorUserId="6467" LastEditDate="2022-05-27T21:45:27.620" LastActivityDate="2022-11-06T18:16:14.667" Title="Could pumping ocean water into desert areas help reduce sea level rise?" Tags="|climate-change|water|sea-level|geoengineering|" AnswerCount="4" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18920" PostTypeId="1" AcceptedAnswerId="18926" CreationDate="2020-01-09T16:35:52.190" Score="33" ViewCount="12939" Body="&lt;p&gt;Why doesnt mankind &quot;collect&quot; thermal energy (there has to be some way: thermal couplings, detour over chemical energy, whatever) and after it has been concentrated at one point, turn it to electrical energy (like steam turbines do) or at least radiate it to space?&lt;/p&gt;&#xA;" OwnerUserId="18652" LastEditorUserId="6467" LastEditDate="2022-07-05T15:55:55.193" LastActivityDate="2023-07-18T15:36:53.847" Title="Global warming - why doesn´t mankind collect heat (thermal energy) and turn it into electricity or send it to space?" Tags="|climate-change|geoengineering|thermodynamics|" AnswerCount="12" CommentCount="20" ContentLicense="CC BY-SA 4.0" />
  <row Id="18922" PostTypeId="2" ParentId="18920" CreationDate="2020-01-09T17:56:05.547" Score="-1" Body="&lt;p&gt;Mankind does collect natural sources of heat and turn it into useful energy: heat pumps, solar arrays, geothermal etc, but it would be impossible to reduce global warming in this way. Most of the heat collected for useful purposes is in any case given back to the atmosphere when the energy is used. If you think about it, even wind farms are collecting solar energy, because it is the sun's heat which drives the winds. When the energy is used, it is re-converted into heat. As a physics student you should know this.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-09T17:56:05.547" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18923" PostTypeId="2" ParentId="18918" CreationDate="2020-01-09T18:21:23.673" Score="-4" Body="&lt;p&gt;Yes, it could reduce sea level rise, but it would be no good for irrigation. Many deserts, like the Aral Sea and Death Valley, are below sea level. This means you would not need to use energy to pump the water, but could use the siphon principle. Some people say that even if you filled all these low-lying deserts with sea water, it would not do much to lower sea level. However, it would have many other beneficial effects, especially in the Aral Sea. It would greatly improve marine transport, create new fisheries, prevent the present salt desert being blown onto agricultural land, and quite likely change the climate so there would be more precipitation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another way to reduce sea level, though it would be only by a tiny amount, would be to build more dams. Deprived of the held-back rain water, the sea level would reduce a little if enough rainwater was prevented from reaching the sea. The dams would produce carbon neutral power, create fisheries and be used for irrigation. On the other hand, if the proposed dams on the Nile are anything to go by, they also have the potential to start wars unless they are sited with great care and good international diplomacy and cooperation.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-09T18:21:23.673" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="18924" PostTypeId="2" ParentId="18920" CreationDate="2020-01-09T18:48:39.103" Score="56" Body="&lt;p&gt;This is due to thermodynamics, the three laws of which can be summarized as 1) You can't win; 2) You can't even break even; 3) You can't leave the game.&lt;/p&gt;&#xA;&lt;p&gt;The crucial point here is that heat engines don't actually work on heat, they work on temperature differences.  So you can't really &amp;quot;collect&amp;quot; heat and turn it into other forms of energy, because you need a colder place to transfer the heat to in order to convert the heat to say electricity.  Which is why power plants are usually situated by oceans, lakes, or rivers, in order to use the water as the cold side of the generator.  (And ones that aren't have large cooling towers, in order to use the air.)&lt;/p&gt;&#xA;&lt;p&gt;When you do move heat around, say with the heat pumps used for home heating and cooling, you're always using some extra energy to &amp;quot;pump&amp;quot; the heat from one place or another.  If you're heating, you move some heat from the ground outside to your house, but the net result is that the system of ground+house gets a bit warmer, because the electricity used for the pump becomes heat.&lt;/p&gt;&#xA;&lt;p&gt;WRT sending the heat back into space, that's actually the cause of global warming.  Atmospheric CO2 acts as an insulating blanket, preventing some of the sun's heat from being radiated back out into space.  By increasing the amount of CO2 in the atmosphere, we've increased the thickness of the blanket, so the Earth gets warmer.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastEditorUserId="27135" LastEditDate="2022-07-05T02:17:24.340" LastActivityDate="2022-07-05T02:17:24.340" CommentCount="17" ContentLicense="CC BY-SA 4.0" />
  <row Id="18925" PostTypeId="2" ParentId="18920" CreationDate="2020-01-10T00:53:01.550" Score="11" Body="&lt;p&gt;Like &lt;a href=&quot;https://www.nature.com/articles/d41586-019-03911-8&quot; rel=&quot;noreferrer&quot;&gt;passive radiative cooling&lt;/a&gt;?&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The new materials reflect a broad spectrum of light, in much the same way as mirrors or white paint do. In the crucial 8–13-µm part of the infrared spectrum, however, they strongly absorb and then emit radiation. When the materials point at the sky, the infrared rays can pass straight through the atmosphere and into space. That effectively links the materials to an inexhaustible heat sink, into which they can keep dumping heat without it coming back. As a result, they can radiate away enough heat to consistently stay a few degrees cooler than surrounding air; research suggests that temperature differences could exceed 10°C in hot, dry places.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="14914" LastActivityDate="2020-01-10T00:53:01.550" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18926" PostTypeId="2" ParentId="18920" CreationDate="2020-01-10T07:46:10.177" Score="32" Body="&lt;p&gt;Collecting thermal energy is really hard. As others have said, things like heat pumps exist for moving heat around, but the laws of thermodynamics (which are fairly fundemantal in physics) require that moving heat around will always generate &lt;em&gt;more&lt;/em&gt; heat. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, the amount of extra heat generated can be less than the amount of heat that's being moved - so if we had a way to build a heat pump that moved heat out of the earth system and into space, then it might be worthwhile. There are three problems with that,&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;We don't know how to do that. A system of pipes going into orbit probably isn't practical!&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Having got the heat into orbit, getting it away from the equipment and into space is hard. You've probably learned about heat moving by conduction, convection, and radiation? The first two are not available in space, because there's no material to conduct into and no atmosphere to convect. So radiation is all that's left. On top of the hypothetical heat pump to orbit, we'd need a massive radiator system in orbit as well.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The scale at which it would have to be done is &lt;em&gt;gigantic&lt;/em&gt;. Even if we knew how to do it, we might not be &lt;em&gt;able&lt;/em&gt; to do it.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;So it probably isn't &lt;em&gt;theoretically&lt;/em&gt; impossible - at least so far as we know - but it's not something that's possible at the moment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's also worth noting that like all ideas that are about getting rid of heat rather than reducing the greenhouse effect, it doesn't actually solve the problem - it just mitigates the symptom. If we carried on emitting greenhouse gases while using this system then we'd have to &lt;em&gt;keep&lt;/em&gt; using this system, more and more, for ever.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(theoreticians: am I missing something? Is there actually a theoretical, rather than practical, blocker here?)&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2020-01-10T07:46:10.177" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="18927" PostTypeId="1" CreationDate="2020-01-10T10:08:05.343" Score="3" ViewCount="2520" Body="&lt;p&gt;In most geology papers, major elements chemical analyses are expressed as mass fraction of oxides, i.e. SiO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; 64.2 wt%, K&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;O 4.3 wt%, etc. The mass fraction unit is &lt;em&gt;always&lt;/em&gt; abbreviated as &quot;wt%&quot;. Even my bible when it comes to igneous rocks classification/terminology (&lt;a href=&quot;https://doi.org/10.1017/CBO9780511535581&quot; rel=&quot;nofollow noreferrer&quot;&gt;Le Maitre et al. 2002&lt;/a&gt;) uses it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What bothers me is that &quot;wt&quot; refers to the weight, which is a force, not a mass. I know it is common usage to use &quot;weight&quot; to refer to the mass of an object, but when writing science shouldn't we be more accurate and use the proper words? Molar and volume fractions are &lt;a href=&quot;https://en.wikipedia.org/wiki/Mass_fraction_(chemistry)&quot; rel=&quot;nofollow noreferrer&quot;&gt;abbreviated&lt;/a&gt; mol% and vol%, respectively. Isn't it time for the &quot;ma%&quot; or &quot;mas%&quot; revolution? If I write &quot;mas%&quot; in a paper, will the reviewers/editors accept it?&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-02-25T16:26:11.540" Title="Why is mass fraction always abbreviated wt% and not ma%?" Tags="|geochemistry|terminology|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18928" PostTypeId="2" ParentId="18920" CreationDate="2020-01-10T10:31:16.903" Score="6" Body="&lt;p&gt;As others have pointed out, if you &lt;em&gt;use&lt;/em&gt; the energy, it turns right back into heat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Radiating it back to space is at least theoretically possible.  But there is a problem with &lt;em&gt;scale&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth receives about a 100 petawatts of energy from the sun. And it radiates almost exactly the same amount back out. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Everything&lt;/em&gt; humanity do with energy is about 0.02 petawatts.  Even if we radiated &lt;em&gt;all&lt;/em&gt; that energy into space it still wouldn't matter much.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Still, it is barely possible to do something like this, by bouncing the sun's light off the Earth surface as it arrives.  While mirrors would be ideal for this job, they are expensive.  Fortunately, any really bright white object does almost as good a job.&#xA;Look up &lt;a href=&quot;https://en.wikipedia.org/wiki/Albedo&quot; rel=&quot;noreferrer&quot;&gt;Albedo&lt;/a&gt; for more information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It would take a very large area of land to make any difference.  And land is expensive.  And we would need a lot of white stuff to do the job.  Even if it is cheap by the square meter (sq feet), it will be expensive by the million square kilometer (million sq mile).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, this is on the list of things we could do if we only found the money for it.&lt;/p&gt;&#xA;" OwnerUserId="6697" LastActivityDate="2020-01-10T10:31:16.903" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18929" PostTypeId="2" ParentId="18927" CreationDate="2020-01-10T11:09:50.917" Score="3" Body="&lt;p&gt;My speculation is that if you try to use ma% or mas%, you will be asked to change it to wt%, because what you are proposing is not yet standard usage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I came across ma%, my initial though would be &quot;what does that mean&quot;. My second thought would be, &quot;does it mean milli annums percent?&quot;, (thousandsths of a year percent) - which would be meaningless to me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to introduce a new terminology, I would suggest not using abbreviations. Instead, use mass% to make things clear.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can try to lobby the body responsible for units used in the Metric system to change from wt% to something else, but until a change has been adopted, which may take years, keep using standard notation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My speculation about the continued use of &lt;em&gt;weight percent (wt%)&lt;/em&gt; is due to English language usage and the persistence of habits.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a very long time, with English, it has been common practice to say something like &quot;how much does that weigh&quot;. It rolls off the tongue easily. At a doctor's surgery people will be asked &quot;how much do you weigh&quot;, not &quot;what is you mass&quot;. Most people don't know what mass means in an every day scientific context, but they do know about weight.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2020-01-10T17:57:21.730" LastActivityDate="2020-01-10T17:57:21.730" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18930" PostTypeId="1" CreationDate="2020-01-10T11:55:30.820" Score="1" ViewCount="161" Body="&lt;p&gt;I have an &lt;a href=&quot;https://atmotube.com/products/atmotube-pro?view=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atmotube Pro&lt;/a&gt; air quality sensor placed outside in a cup with a large bowl placed over the top of it to protect it from the wind and any rain but to allow air to filter through easily.&lt;/p&gt;&#xA;&lt;p&gt;I'm trying to understand what might be the reason for the pattern of volatile organic compounds (VOCs) I am seeing.&lt;/p&gt;&#xA;&lt;p&gt;The weather is partly cloudy today with some intermittant sunshine in my south of England city (the sun is not that strong with it being January).  The monitor is placed on top of a 1st floor bay window.  The wind is about 10mph NW and the temperature 6-7C.  I live in a 250k populated densly packed city on a quiet road 150m from a couple of 30kmh limit busy roads and junction.&lt;/p&gt;&#xA;&lt;p&gt;I have had similar patterns of high VOC levels in the past with them suddenly falling.  I think it starts to rise when it gets sunny then falls as soon as the sun goes away.&lt;/p&gt;&#xA;&lt;p&gt;What would be the most common reason for this pattern (sometimes the readings go to 2.0ppm)&lt;/p&gt;&#xA;&lt;p&gt;VOCs emitted from roof when sun hits it (it is a lead roof)?  Traffic building up?  Pollution blown in from somewhere else?  Fault with sensor?  Traffic pollution turning into something else in the sunshine?  Sudden changes in wind when it becomes cloudy?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/L2u9n.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/L2u9n.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IZ4q5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IZ4q5.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/78TUd.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/78TUd.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;13:02 - 13:55 in one minute intervals, it is this difference in one minute that I am confused about 0.763, 0.37&lt;/p&gt;&#xA;&lt;p&gt;0.356, 0.363, 0.373, 0.439, 0.507, 0.572, 0.622, 0.661, 0.763, 0.37, 0.356, 0.346, 0.334, 0.341, 0.354, 0.38, 0.347, 0.354, 0.333, 0.319, 0.323, 0.335, 0.35, 0.373, 0.477, 0.55, 0.35, 0.338, 0.341, 0.344, 0.345, 0.362, 0.333, 0.348, 0.364, 0.403, 0.519, 0.583, 0.624, 0.69, 0.66, 0.702&lt;/p&gt;&#xA;" OwnerUserId="18003" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-01-10T16:17:30.660" Title="What is the reason for this high outdoor VOC level with strange pattern of slow rise and sudden falling?" Tags="|meteorology|air-pollution|pollution|air-quality|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="18931" PostTypeId="2" ParentId="18890" CreationDate="2020-01-10T15:01:20.187" Score="-1" Body="&lt;p&gt;Much has been said about the negative effects, but there are positive effects as well. In UK thousands of old folk are speeded on their way to the promised land by hard winters, so milder winters will save thousands of lives. Excessively hot summers can also cost lives, but in UK those killed by cold weather greatly outnumber those killed by heat waves. Another beneficial effect is that the NW and NE Passages will be opened up to shipping, enabling ships to take short cuts to their destinations, use less fuel and thus cut CO2 emissions. Another benefit, provided the heating doesn't go too far, is that warm climates have greater biodiversity than cold climates. Of course, that means that cold-loving species like Gyrfalcons and Ptarmigan will be pushed further north or onto higher ground (Gyrs have never bred in Britain,Ptarmigan do,and Snowy Owls occasionally). A number of new species including Little Egrets and Cattle Egrets are already colonising the south of UK.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A cooler climate would also have both positive and negative effects, but we are not likely to get that for some considerable time.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-10T15:01:20.187" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="18932" PostTypeId="1" AcceptedAnswerId="18992" CreationDate="2020-01-10T15:05:58.880" Score="2" ViewCount="70" Body="&lt;p&gt;I'm currently working on a project in which I need to create a metric to quantify drought. For the state of Pennsylvania, I have daily precipitation data from many NOAA precipitation gauges (inches of rain per day). I am attempting to create a metric that can quantify how much rainfall certain areas received, hopefully boiling it down to one number. The goal of the metric is to describe the 1960's drought. What's the best way to do this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've looked into many scientific papers for similar metrics, but most use more in depth models, and not just daily precip data. What are some good ideas? Average daily/weekly/monthly? Average number of days without rainfall?&lt;/p&gt;&#xA;" OwnerUserId="18665" LastActivityDate="2020-01-17T15:12:46.550" Title="Creating a drought metric using precipitation data?" Tags="|precipitation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18933" PostTypeId="1" CreationDate="2020-01-10T15:17:42.520" Score="1" ViewCount="135" Body="&lt;p&gt;There is recorded evidence from solar eclipses that the &lt;a href=&quot;https://www.nationalgeographic.com/news/2012/3/120328-solar-eclipses-winds-weather-sun-earth-space-science/&quot; rel=&quot;nofollow noreferrer&quot;&gt;moon's shadow has a detectable weather effect&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we placed a disk in space we could project a cold spot onto the planet and control it's position using the position of the spacecraft. In simple terms warm air moves towards cold, so that could be used to pull weather systems out of their normal track.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;What is the smallest disk that would create a 300km shadow&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Where would be the best place to put it between the earth and sun&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;What size of effect would you have?&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Could you move a monsoon from flooded Asia to drought Australia&lt;/li&gt;&#xA;&lt;li&gt;How big would the shadow need to be to have an appreciable effect?&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;If it was always &quot;on&quot; (i.e. you could turn it &quot;off&quot; by rotating it on edge), would the cooling effect be significant?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;It's not going to stop global warming but it might buy some time and help redistribute the water more evenly.&lt;/p&gt;&#xA;" OwnerUserId="18664" LastActivityDate="2020-01-10T18:12:34.593" Title="Could we control the weather with a disk in space?" Tags="|climate-change|weather-satellites|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18934" PostTypeId="2" ParentId="18933" CreationDate="2020-01-10T15:45:48.830" Score="0" Body="&lt;p&gt;It would have to be a hell of a big disc, and in a geostationary orbit. No, it's not practical, we can never control the weather with satellites in space. It's a non-starter. What might be done with satellites is to reflect the sun's rays into frostbound valleys where there is a small town in shadow which is not getting the benefits of spring as early as other nearby towns. It could also be used for night time street lighting. However, I doubt whether the results would justify the expense, and there are bound to be people who wouldn't like it. The things you mention in your question are not possible.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-10T15:45:48.830" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18935" PostTypeId="1" CreationDate="2020-01-10T17:01:11.660" Score="7" ViewCount="163" Body="&lt;p&gt;The scientific community expressed concern that global 5G would potentially threaten weather forecasts by scrambling frequencies in the microwave spectrum used for water vapor, atmospheric temperature and snow/ice observation by weather satellites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/d41586-019-01305-4&quot; rel=&quot;noreferrer&quot;&gt;https://www.nature.com/articles/d41586-019-01305-4&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first 5G installations are out now, mostly in Asia i think. Politics aside, please, is there any effect on weather forecast known already, or is it too early to state ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://public.wmo.int/en/media/news/wmo-expresses-concern-about-radio-frequency-decision&quot; rel=&quot;noreferrer&quot;&gt;WMO press release&lt;/a&gt; from November. They say that if 5G is rolled out too fast, the limits set from the regulators will be too low maintain forecast quality and range.&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-10T19:38:15.083" LastActivityDate="2021-03-26T12:49:29.683" Title="5G interference with weather observation, a thing already?" Tags="|meteorology|weather-forecasting|weather-satellites|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18937" PostTypeId="2" ParentId="18933" CreationDate="2020-01-10T17:35:39.433" Score="2" Body="&lt;p&gt;Maybe this question belongs also into the space department here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only Lagrange point that makes sense is &lt;a href=&quot;https://www.esa.int/Science_Exploration/Space_Science/L1_the_first_Lagrangian_Point&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth - Sun - L1&lt;/a&gt;, and it is unstable (needs continuous correction). Satellites have already been put there, e.g. &lt;a href=&quot;https://sohowww.nascom.nasa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;SOHO&lt;/a&gt;. But what we really need to do is cut down greenhouse gas emissions, anything else is not sustainable, or not practicable (a 300km sail in L1 belongs to the latter). Looking at the problems NASA has with the heat shield of the &lt;a href=&quot;https://www.jwst.nasa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;James Webb telescope&lt;/a&gt; i am tempted to say that it is not makeable with current technology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geostationary orbit is not an option. The spacing between satellites is much too small and the shield would only cover the equator. Even in geosynchronuous orbits the satellite spacing is down to 73km (&lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_satellites_in_geosynchronous_orbit&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/List_of_satellites_in_geosynchronous_orbit&lt;/a&gt;) i read, so that's also occupied for such a frond. It'll collide in the ascending/descending nodes with other stuff.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.nature.com/articles/ncomms4304&quot; rel=&quot;nofollow noreferrer&quot;&gt;risks of geo- and climate engineering&lt;/a&gt;, e.g. lack of knowledge about possible side effects and the potentially drastical acceleration of global warming when engineering efforts cease (out of money error ;-)) and the time when they were in effect has not been used to cut down greenhouse gas emissions, are huge.&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-10T18:12:34.593" LastActivityDate="2020-01-10T18:12:34.593" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18938" PostTypeId="1" AcceptedAnswerId="18943" CreationDate="2020-01-10T18:03:31.370" Score="2" ViewCount="113" Body="&lt;p&gt;Using AirVisual app I notice there is a huge patch of pollution in Africa. I cannot imagine there is a big economic activity to support that huge pollution across almost the whole continent. What could be the cause of those pollution in Africa. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EjVw9.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EjVw9.jpg&quot; alt=&quot;pollution in Africa&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18670" LastActivityDate="2020-01-11T12:15:36.743" Title="What creates so much pollution in Africa?" Tags="|air-pollution|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18939" PostTypeId="2" ParentId="18920" CreationDate="2020-01-10T18:44:32.777" Score="1" Body="&lt;p&gt;Of all the types of energy there is, heat is the &quot;waste&quot; of the energies. See, energy is only useful if organized, and heat is the least organized of them all. I.e, the energy must be able to push car wheel in that particular direction, not to every direction at random, like molecules of a hot gas would.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to reorganize the energy, according to the laws of physics (the second law of thermodynamics, in particular), you must have a cold place to where the heat could flow. Most (all?) heat engines relies on the environment being colder than the heat source in order for it to work: a car or a airplane engine only works because the ambient temperature is smaller than the temperature inside the engine, and a coal plant relies on the ambient being cooler than the steam turning the turbines.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By being immersed in a hot ambient, you can't use that very ambient as the cold side in order to extract energy from it, so you can't possibly build a device that is powered solely on the heat of the environment it is immersed in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is one half of the problem. The other is: if we could extract energy from the environmental temperature, we would certainly not radiate it away to space: we would use it as electricity, power our cars, planes, and would never need fossil fuels again.&lt;/p&gt;&#xA;" OwnerUserId="18671" LastEditorUserId="18671" LastEditDate="2020-01-10T18:53:17.027" LastActivityDate="2020-01-10T18:53:17.027" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18940" PostTypeId="2" ParentId="18920" CreationDate="2020-01-10T22:31:55.467" Score="1" Body="&lt;p&gt;Fossil fuel based energy is very inefficient; the amount of heat wasted exceeds that which gets used. In addition &lt;a href=&quot;http://www.cgd.ucar.edu/tss/ahf/&quot; rel=&quot;nofollow noreferrer&quot;&gt;global heating from enhanced greenhouse effect is adding heat at rates estimated at around 100 times that from total waste heat.&lt;/a&gt; In order to get zero global heating (whilst continuing to burn fossil fuels) by collecting heat and sending it to space requires collecting &lt;em&gt;in excess of a hundred times more energy than human economies are currently using&lt;/em&gt; as well as developing and building and operating the technology to send all that heat somewhere else, ie to space. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That is effectively impossible, but developing a means to utilise low grade heat for energy generation could significantly aid the displacement fossil fuel burning, that would reduce global heating by that factor of a hundred. Technology for turning low grade heat into higher grade energy exists - eg Stirling engines - but they are not cost effective. Some other tantalising possibilities do exist, such as Nantennas aka &lt;a href=&quot;https://en.wikipedia.org/wiki/Optical_rectenna&quot; rel=&quot;nofollow noreferrer&quot;&gt;Optical Rectennas&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, effective low emissions energy options that reduce fossil fuel use and the enhanced greenhouse warming and that are cost effective already exist; I think those should be the primary focus of our current response to global warming.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2020-01-10T22:31:55.467" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18942" PostTypeId="2" ParentId="18920" CreationDate="2020-01-11T03:59:09.300" Score="2" Body="&lt;p&gt;Your idea: concentrating the heat, using the energy for something useful and then dissipating it into space could actually be accomplished by a &lt;a href=&quot;https://en.wikipedia.org/wiki/Space_mirror_(climate_engineering)&quot; rel=&quot;nofollow noreferrer&quot;&gt;space mirror&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a special orbit called L1 that's in between the Earth and the Sun and is just the right distance so that something in that orbit will track and orbit in sync with the Earth.  It could both shade the Earth a bit and be a massive power plant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might check out this &lt;a href=&quot;https://www.livescience.com/22202-space-mirrors-global-warming.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;article from live science on space mirrors&lt;/a&gt;.  It goes over the pros and cons of this idea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wikipedia also has an &lt;a href=&quot;https://en.wikipedia.org/wiki/Space_mirror_(climate_engineering)&quot; rel=&quot;nofollow noreferrer&quot;&gt;entry&lt;/a&gt; on this idea.&lt;/p&gt;&#xA;" OwnerUserId="18676" LastEditorUserId="18676" LastEditDate="2020-01-12T02:22:08.943" LastActivityDate="2020-01-12T02:22:08.943" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="18943" PostTypeId="2" ParentId="18938" CreationDate="2020-01-11T12:15:36.743" Score="1" Body="&lt;p&gt;What you can see in your image is mostly dust from the shara desert &lt;a href=&quot;https://earth.nullschool.net/#current/particulates/surface/level/overlay=pm10/orthographic=13.33,5.70,766&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earth.nullschool.net/#current/particulates/surface/level/overlay=pm10/orthographic=13.33,5.70,766&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You will be able to see other types of particles like smoke from combustion like cars-industry-forrest fires,the picture show particles that is 10 microns in size.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the linked page you can find details of other types of chemical and particulate emissions too like SO2 and CO2 it is a good source for information about the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastActivityDate="2020-01-11T12:15:36.743" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18945" PostTypeId="2" ParentId="18920" CreationDate="2020-01-11T19:10:25.743" Score="4" Body="&lt;p&gt;Just to hammer it down: the amount of energy transferred to Earth by the sun every single day is &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_energy_budget&quot; rel=&quot;nofollow noreferrer&quot;&gt;colossal&lt;/a&gt;. In comparison, the heat generated by all human activities is negligible.&#xA;For instance, burning every single tree on Earth would release less than 1% of the heat the sun sends our way every day!&lt;br&gt;&#xA;Taking human activities as an intuitive reference point is utterly misleading. Heat exchanges in the atmosphere involve massive amounts of energy that are far beyond anything human industrial capabilities can handle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Greenhouse gases act like a kind of space blanket: a very thin and light insulating layer that can still trap quite a lot of heat.&lt;br&gt;&#xA;Though the excess of gases we release only capture a tiny extra fraction of it (well below 1%), the energy the sun sends our way is so tremendous that this little extra heat is enough to mess up our climate badly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Our problem is not to make any use of this extra solar energy. We could move around a minute fraction of it to our advantage (for instance concentrating it inside a house in winter and pumping it out in summer), but as a global system our habitat (the surface of the Earth and a bit of breathable atmosphere above) is receiving far, far too much heat, on a scale that dwarves all human uses of energy.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Our problem is to get rid of it, that means sending it some place where it can't wreak havoc with our climate. At this scale, that leaves only outer space or deep soil as potential dumps.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far our atmosphere did quite a nice job of sending solar energy back into space, but we fouled it up. What a bummer...&lt;br&gt;&#xA;We sure could think of just moving all that heat out of the way ourselves. But alas, as the 2nd law of thermodynamics and its dreaded entropy states, any kind of mechanical work requires additional energy and generates more heat. Even a refrigerator adds more heat into the environment than it pumps out of its internal compartment.&#xA;All we can hope to achieve is transfer heat from place to place. At the cost of more energy, raw materials, time, industrial capacity and, naturally, money.&lt;br&gt;&#xA;That is dictated by fundamental laws of physics that no amount of wishful thinking can sway.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Painting deserts white or drilling deep underground geothermal wells or putting fancy space radiators into orbit are just sci-fi fantasies.&lt;br&gt;&#xA;We simply don't even come close to having the energy, materials and technology to implement any of these on a scale that would solve the problem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Picture yourself being wrapped in a space blanket, getting a bit too hot for comfort. Trying to move the hot air away from your body will only make you warmer, while removing the blanket might cool you down fast, with a lot less efforts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Indeed, the only thing we could hope to act upon is the blanket itself.&lt;br&gt;&#xA;Wisdom would dictate to start by not making it any thicker. Stop burning fossil fuels and breeding farting cattle for a couple of centuries, waiting for all the junk we spewed so far to dissipate.&lt;br&gt;&#xA;There is also the crackpot scientist alternative: spewing more junk (like sulphur) into the atmosphere to try and mitigate the greenhouse effect. Frankly I hope I'll be dead before I see the idiots try.&lt;/p&gt;&#xA;" OwnerUserId="18680" LastEditorUserId="18680" LastEditDate="2020-01-11T20:12:52.233" LastActivityDate="2020-01-11T20:12:52.233" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="18946" PostTypeId="2" ParentId="18920" CreationDate="2020-01-11T20:06:48.313" Score="1" Body="&lt;p&gt;The problem with turning many forms of waste heat into other forms of energy by conventional (heat engine) methods is that significant temperature differences are needed - and that the temperatures making up the differences are counted from absolute zero (0 Kelvin). Only if that ratio is large, you get an efficient conversion. For example, if you look at the waste heat from a computer CPU, it might be at 340 Kelvin, 40 degrees Kelvin (Kelvins are absolute-zero-referenced centigrades for you Fahrenheit types) over an ambient temperature of, 300 Kelvin. You can't force the heat to build up to much higher levels since you will damage the CPU. The efficiency of a heat engine trying to make anything useful of this situation would be 40K/340K*100% = drumroll ... 11%. Hardly WORTH trying to recover.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is because Carnot, one of the patron bastards of physics, made that the law in 1824, and no one repealed it yet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This does not apply to heat &lt;em&gt;radiation&lt;/em&gt;, which isn't heat per se but heat that has already been converted into long wave infrared light, which gets converted back into heat if it hits something. It can indeed be relayed at will by lenses, mirrors and prisms made of the appropriate materials (not: run of the mill window or optical glass!). Unfortunately, creating significant heat radiation is also something that takes high temperatures....&lt;/p&gt;&#xA;" OwnerUserId="18538" LastEditorUserId="18538" LastEditDate="2020-01-11T21:28:44.363" LastActivityDate="2020-01-11T21:28:44.363" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18947" PostTypeId="2" ParentId="18920" CreationDate="2020-01-11T22:50:31.413" Score="1" Body="&lt;p&gt;&lt;strong&gt;Well the most straight forward way to radiate sunlight into space is with a mirror.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But creating millions of square miles worth of mirrors sounds very expensive.  Probably in the range of a 100s of Trillions of US dollars.  If we got rid of all government spending we might be able to pay for it over the course of a 100 years or so.&lt;/p&gt;&#xA;" OwnerUserId="18682" LastActivityDate="2020-01-11T22:50:31.413" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18948" PostTypeId="2" ParentId="18890" CreationDate="2020-01-12T02:30:22.180" Score="0" Body="&lt;p&gt;If you consider what climate is -- the typical range of temperatures, precipitation, and other meteorological conditions that a region experiences -- and the fact that both nature and human society and civilization have adapted to the regional climates across the globe, then you can see that any substantial and relatively rapid change is likely to have what we would perceive as negative effects.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is just a broad illustration, but for example, there's a vast swath of the north hemisphere suitable for growing wheat because of a combination of soil quality, available precipitation, and growing degree days (crop heat units). Farms, cities, roads, and other infrastructure have been built around this cropland for generations to take optimal advantage of existing conditions and reduce costs for delivering the wheat to market. More crop heat units can make a region more productive, but daily temperatures above 82 degrees will start stressing and killing the plants. Even if land closer to the poles becomes more farmable -- no guarantee -- simply changing what can be brown at a given latitude can reduce a nation's ability to feed itself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are other ways in which human civilization has adapted to current regional conditions: Communities rely on air conditioning in the summer and/or heating in the winter to make regions tolerable. Harbors and coastal communities are built to suit current sea levels. In general, increased temperatures will make warmer regions less tolerable and more expensive to live in (&lt;a href=&quot;https://www.nature.com/articles/s41467-019-10399-3&quot; rel=&quot;nofollow noreferrer&quot;&gt;through cooling and similar costs&lt;/a&gt;) and &lt;a href=&quot;https://www.yaleclimateconnections.org/2019/06/heat-waves-and-climate-change-is-there-a-connection/&quot; rel=&quot;nofollow noreferrer&quot;&gt;more prone to deadly heat waves&lt;/a&gt;, while potentially making colder regions more tolerable and less expensive (through reduced heating costs). Similarly, dramatic cooling would also affect where everything grows, reduce growing degree days for growing plants, and making colder regions less tolerable and more costly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;While attempting to quantify the &quot;&lt;a href=&quot;https://www.nature.com/articles/s41558-018-0282-y.epdf?author_access_token=XLBRLEGdT_Kv0n8_OnvpedRgN0jAjWel9jnR3ZoTv0Ms70oz073vBeHQkQJXsJbey6vjdAHHSPxkHEN8nflPeQI6U86-MxWO1T1uUiSvN2A-srp5G9s7YwGWt6-cuKn2e83mvZEpXG3r-J0nv0gYuA%3D%3D&quot; rel=&quot;nofollow noreferrer&quot;&gt;Country-level social cost of carbon&lt;/a&gt;,&quot; a 2018 study in &lt;em&gt;Nature Climate Change&lt;/em&gt; by Kate Ricke, et. al. assessed the net economic impact on individual countries and concluded that the costs are &quot;unevenly distributed&quot;: &quot;Countries that incur large fractions of the global cost consistently include India, China, Saudi Arabia and the United States.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Northern countries such as Russia, Canada, Norway, Sweden, the United Kingdom, France, Germany, and Poland actually receive a slight direct benefit from climate change through factors such as reduced heating costs.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2020-01-12T02:30:22.180" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18951" PostTypeId="2" ParentId="17990" CreationDate="2020-01-12T14:43:02.970" Score="3" Body="&lt;p&gt;Because the first few decades are crucial, so we are pragmatically buying time until we manage the transition from fossil fuels to clean energy sources.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I heard a podcast announcing Ted's initiative called Countdown, where they presented planting a trillion trees as a solution. A company Flash Forest is being founded on Kickstarter to the amount of 100k to plant a billion trees with drones.&lt;/p&gt;&#xA;" OwnerUserId="18694" LastActivityDate="2020-01-12T14:43:02.970" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18953" PostTypeId="1" CreationDate="2020-01-12T19:58:41.097" Score="7" ViewCount="791" Body="&lt;p&gt;I have an argument with a climate change denier.&lt;/p&gt;&#xA;&lt;p&gt;He says the rise of water vapor in the atmosphere causes a &amp;quot;much larger&amp;quot; cooling effect by taking vaporisation heat from the ground than the heat generated by the additional greenhouse effet.&lt;/p&gt;&#xA;&lt;p&gt;I say the additional greenhouse effect integrates with time, so after a certain time T (which I suspect &amp;quot;small&amp;quot;), this heat will compensate the latent heat taken from the ground.&lt;/p&gt;&#xA;&lt;p&gt;Does anyone have a reference establishing the order of magnitude of T ?&lt;/p&gt;&#xA;&lt;p&gt;Note the question is NOT about the &amp;quot;normal&amp;quot; water cycle where latent heat is taken at vaporisation and released at condensation, it is about the (undisputed) global augmentation of water vapor in the troposphere.&lt;/p&gt;&#xA;" OwnerUserId="18695" LastEditorUserId="21926" LastEditDate="2021-03-26T16:38:20.903" LastActivityDate="2023-03-07T00:12:27.167" Title="Time for water vapor to generate more greenhouse effect than latent heat?" Tags="|climate-change|greenhouse-gases|water-vapour|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18955" PostTypeId="1" AcceptedAnswerId="18956" CreationDate="2020-01-13T02:54:10.437" Score="3" ViewCount="94" Body="&lt;p&gt;If two people are standing next to each other during a polar night, and the brightest possible aurora is occurring overhead, could one person see the other person's face clearly?&lt;/p&gt;&#xA;" OwnerUserId="14986" LastEditorUserId="14986" LastEditDate="2020-01-13T03:55:38.673" LastActivityDate="2020-01-14T19:53:30.177" Title="Can an aurora australis be bright enough to illuminate someone's face?" Tags="|auroras|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18956" PostTypeId="2" ParentId="18955" CreationDate="2020-01-13T05:42:03.830" Score="5" Body="&lt;p&gt;If your eyes are fully adapted to the darkness you will be able to see a persons face in the light from the auroras.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By fully adapted to darkness means sitting in a totally dark room for 20+ minutes before you start looking at the night sky. The time you will need to adapt depends on your age.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any bright light will destroy your night vision. As we get older our night vision will get poorer so young people will see better at night than older people do.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="17730" LastEditDate="2020-01-14T19:53:30.177" LastActivityDate="2020-01-14T19:53:30.177" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18957" PostTypeId="1" AcceptedAnswerId="18959" CreationDate="2020-01-13T09:41:41.420" Score="1" ViewCount="79" Body="&lt;p&gt;Can anyone recommend a good source for high-resolution georeferenced population data? I know that &lt;a href=&quot;https://www.naturalearthdata.com/downloads/10m-cultural-vectors/&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Natural Earth Data's&lt;/em&gt; Cultural Vectors&lt;/a&gt; e.g. contain the population per country. However, I am looking for georeferenced global population data with a higher resolution than on a country level. Obviously, Wikipedia and other sources feature data for some country's states or cities but is there a database (ideally) georeferenced which features such data on a global level?&lt;/p&gt;&#xA;" OwnerUserId="17641" LastActivityDate="2020-01-13T10:56:37.670" Title="High-resolution georeferenced population data" Tags="|open-data|gis|" AnswerCount="1" CommentCount="3" ClosedDate="2020-01-15T21:47:39.260" ContentLicense="CC BY-SA 4.0" />
  <row Id="18959" PostTypeId="2" ParentId="18957" CreationDate="2020-01-13T10:46:09.480" Score="7" Body="&lt;p&gt;For &quot;historical&quot; population data, you can refer to the &lt;a href=&quot;https://sedac.ciesin.columbia.edu/data/collection/gpw-v4&quot; rel=&quot;noreferrer&quot;&gt;Gridded Population of the World (GPW), version 4&lt;/a&gt;. This dataset makes available estimates of population at ~1 km resolution (30 arc second) for the years 2000, 2005, 2010, 2015, 2020.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The GPWv4 was also used by the European Commission's Joint Research Centre for the &lt;a href=&quot;https://ghsl.jrc.ec.europa.eu/ghs_pop.php&quot; rel=&quot;noreferrer&quot;&gt;Global Human Settlemen&lt;/a&gt;t project. This dataset makes available residential population estimates for target years 1975, 1990, 2000 and 2015 at 250m and 1km spatial resolution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you also need future projections, you can refer to the Shared Socioeconomic Pathways (SSP) scenarios downscaled by Murakami and Yamagata (&lt;a href=&quot;https://www.mdpi.com/2071-1050/11/7/2106&quot; rel=&quot;noreferrer&quot;&gt;2019&lt;/a&gt;), available &lt;a href=&quot;https://www.cger.nies.go.jp/gcp/population-and-gdp.html&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;, or by Jones and O'Neill (&lt;a href=&quot;https://iopscience.iop.org/article/10.1088/1748-9326/11/8/084003&quot; rel=&quot;noreferrer&quot;&gt;2016&lt;/a&gt;), made available through the &lt;a href=&quot;https://www.isimip.org/gettingstarted/input-data-bias-correction/details/62/&quot; rel=&quot;noreferrer&quot;&gt;ISIMIP project portal&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="8087" LastEditorUserId="8087" LastEditDate="2020-01-13T10:56:37.670" LastActivityDate="2020-01-13T10:56:37.670" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18961" PostTypeId="1" CreationDate="2020-01-14T01:22:19.270" Score="3" ViewCount="102" Body="&lt;p&gt;I run a Trail Store (sell hiking maps, swag, etc) in Mahwah, NJ, USA. I'm trying to feature a plant and rock every season. The first rock chosen is puddingstone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I created the short sign below, mostly from Wikipedia. I followed it with a few questions. I'm hoping the feedback will improve the sign.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Puddingstone, also known as either pudding stone or plum-pudding stone, is a popular name applied to a conglomerate that consists of distinctly rounded pebbles whose colors contrast sharply with the color of the finer-grained, often sandy, matrix or cement surrounding them. The rounded pebbles and the sharp contrast in color gives this type of conglomerate the appearance of a raisin or Christmas pudding.&#xA;There are four types of pudding stone: Hertfordshire, Schunemunk, Roxbury, and St. Joseph Island (Drummond Island) puddingstones.&#xA;This example is Schunemunk puddingstone, which is exposed extensively on Bearfort Mountain, Boonton, Rockaway Township and Schunemunk Mountain. It is a conglomerate that is part of a 3,000 feet (910 m) thick geologic formation formally known as the Skunnemunk Conglomerate. It consists partly of grayish-red and gray sandstone, as well as grayish-red shale. Pebbles and cobbles of white vein quartz, red and green quarzite, red and gray chert, and red shale are also present. The grayish-purple to grayish-red conglomerate and sandstone is cemented largely by hematite (mined as the main ore of iron) and microcrystalline (visible only under a microscope) quartz.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Of the specific rock formations mentioned (sandstone, shale, quartz, chert) - would it be better to leave some of these out if they represent a tinier percentage of the total conglomerate? Are there some other important crystal or rock formations that should be included?&lt;/li&gt;&#xA;&lt;li&gt;Should the following terms be defined - sandstone, shale, quartz, chert? Should the process of &quot;cementing&quot; in terms of the conglomerates (sandstone, shale, quartz, and chert) that get cemented - what happens to these components when they are cemented together? Should the chemical details of how hematite and microcrystalline actually accomplish the cementing be mentioned?&lt;/li&gt;&#xA;&lt;li&gt;Are there any broader environmental concerns that should be included (relation to fossil fuels, relation to important plants that need the puddingstone to thrive, relation to larger structures in its regions such as cliffs, valleys, rivers)?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Thank you,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Gary Willick&lt;/p&gt;&#xA;" OwnerUserId="18703" LastEditorUserId="6" LastEditDate="2020-01-14T10:32:17.960" LastActivityDate="2020-01-14T10:32:17.960" Title="Puddingstone info sign for Trail Store" Tags="|geology|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18962" PostTypeId="5" CreationDate="2020-01-14T03:24:38.030" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2020-01-14T03:24:38.030" LastActivityDate="2020-01-14T03:24:38.030" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18963" PostTypeId="4" CreationDate="2020-01-14T03:24:38.030" Score="0" Body="Questions regarding the state and functioning of soil, its interaction with the biota, hydrosphere and atmosphere" OwnerUserId="3241" LastEditorUserId="3241" LastEditDate="2020-01-14T10:48:15.527" LastActivityDate="2020-01-14T10:48:15.527" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18964" PostTypeId="1" AcceptedAnswerId="18967" CreationDate="2020-01-14T08:49:42.857" Score="37" ViewCount="10484" Body="&lt;p&gt;&#xA;&#xA;&lt;p&gt;My question refers to the current process of climate change. CO&lt;sub&gt;2&lt;/sub&gt; is rising, which leads to the greenhouse effect, which raises temperatures. This leads to more wildfires, which reduces number of trees, increasing CO&lt;sub&gt;2&lt;/sub&gt; and reducing CO&lt;sub&gt;2&lt;/sub&gt; capacity absorption. Ice caps start to melt, which reduces sunlight reflection (less snow), trapping more heat on atmosphere. Water rises, taking over land and trees, further enhancing the CO&lt;sub&gt;2&lt;/sub&gt; absorption capacity. Oceans acidify, lowering their CO&lt;sub&gt;2&lt;/sub&gt; absorption capacity too. Etc etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems the process of climate change is a &quot;vicious circle&quot;, with a lot of feedback loops reinforcing the trends.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is this the case?&lt;/strong&gt; Are there counteracting forces that go against this circle?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Related questions which imo do not provide an answer to this one: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13464/is-global-warming-a-linear-process&quot;&gt;here&lt;/a&gt;, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7737/global-warming-cycles&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="13541" LastEditorUserId="2470" LastEditDate="2020-01-14T10:46:07.283" LastActivityDate="2020-02-15T20:03:39.793" Title="Is climate change a vicious circle?" Tags="|climate-change|" AnswerCount="6" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18965" PostTypeId="2" ParentId="18964" CreationDate="2020-01-14T10:17:04.347" Score="-2" Body="&lt;p&gt;Yes, you are quite right, it does create a vicious circle, though not quite as vicious as some might think. As you suggest, there are natural forces which ameliorate the effects of this vicious circle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of the woodland burned by these fires regenerates, though this takes a while. Where it doesn't regenerate, its place is usually taken by agriculture, which also consumes CO2, but less effectively than trees.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The de-icing of the NW and NE Passages will allow ships to take short cuts to their destinations and thus use less fuel, which lowers CO2 emissions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The increased CO2 in the atmosphere will allow vegetation, both natural and agricultural, to grow more efficiently by perhaps a few percent. This applies not only in the rainforest, but in the oceans where the majority of photosynthesis takes place (in this context I include all photosynthetic marine organisms, not just vegetation as we normally think of it).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just as there are more factors which create a vicious circle, so there are more ameliorating factors which lessen it, but not enough to prevent an increase in the vicious circle you speak of in your question.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-14T10:17:04.347" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18966" PostTypeId="2" ParentId="18964" CreationDate="2020-01-14T10:45:25.277" Score="21" Body="&lt;p&gt;You've correctly identified a number of individual mechanisms which form &quot;vicious circles&quot;. They're more formally known as &quot;positive feedbacks&quot;. As you've noted, loss of albedo (reflectivity) from melted ice is one. Some of the others you've listed are a bit more complex - e.g. trees will regrow, algae in oceans are quite effective at removing CO2, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the big concerns that people have is that if some of the larger positive feedback mechanisms get going - e.g. the melting of frozen methane on the seafloor - then it will impossible for anything that mankind does to stop it, and even if we completely stop emitting greenhouse gases we'll get pushed to a much warmer climate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are also negative feedback mechanisms. For example, a warmer atmosphere is likely to have more clouds, which will reflect more sunlight. But the warmer atmosphere can also hold more water vapour, which itself is a greenhouse gas, which is a positive feedback. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the reasons that climate science is hard is that all of these positive and negative feedbacks interact, making the earth system a very complex one.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2020-01-14T10:45:25.277" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18967" PostTypeId="2" ParentId="18964" CreationDate="2020-01-14T11:04:44.913" Score="42" Body="&lt;p&gt;There are indeed a lot of positive feedback mechanisms, i.e. a warm climate leads to a warmer climate. From &lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_change_feedback&quot; rel=&quot;noreferrer&quot;&gt;this Wikipedia article&lt;/a&gt;, they are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Carbon cycle feedbacks&lt;/li&gt;&#xA;&lt;li&gt;Cloud feedback&lt;/li&gt;&#xA;&lt;li&gt;Gas release&lt;/li&gt;&#xA;&lt;li&gt;Ice-albedo feedback&lt;/li&gt;&#xA;&lt;li&gt;Water vapor feedback&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;However, there are also a few negative feedbacks (same source):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Blackbody radiation&lt;/li&gt;&#xA;&lt;li&gt;Carbon cycle&lt;/li&gt;&#xA;&lt;li&gt;Lapse rate&lt;/li&gt;&#xA;&lt;li&gt;Impacts on humans&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Now the question is: what is the net budget between positive and negative feedbacks? To assess this, climatologists use some metrics, the main ones being &amp;quot;transient climate response&amp;quot; (TCR) and &amp;quot;equilibrium climate sensitivity&amp;quot; (ECS). From &lt;a href=&quot;https://doi.org/10.1038/ngeo3017&quot; rel=&quot;noreferrer&quot;&gt;Knutti et al. (2017)&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;TCR is defined as the global mean surface warming at the time of&#xA;doubling of CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; in an idealized 1% yr&lt;span class=&quot;math-container&quot;&gt;$^{−1}$&lt;/span&gt; CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; increase&#xA;experiment, but is more generally quantifying warming in response to a&#xA;changing forcing prior to the deep ocean being in equilibrium with the&#xA;forcing. Based on state-of-the-art climate models, and instrumentally&#xA;recorded warming in response to CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; and other anthropogenic and&#xA;natural forcings, the Intergovernmental Panel on Climate Change's&#xA;Fifth Assessment Report (IPCC AR5) assessed that the transient climate&#xA;response is 'likely' (&amp;gt;66% probability) to be in the range of 1 °C to&#xA;2.5 °C.&lt;/p&gt;&#xA;&lt;p&gt;By contrast, the equilibrium climate sensitivity (ECS) is defined as&#xA;the warming response to doubling CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; in the atmosphere relative to&#xA;pre-industrial climate, after the climate reached its new equilibrium,&#xA;taking into account changes in water vapour, lapse rate, clouds and&#xA;surface albedo. [...] The estimated range of ECS has not changed much&#xA;despite massive research efforts. The IPCC assessed that it is&#xA;'likely' to be in the range of 1.5 °C to 4.5 °C.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Which basically means that the climate will get warmer in the future, until it will eventually reach some kind of equilibrium.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-01-14T11:04:44.913" CommentCount="16" ContentLicense="CC BY-SA 4.0" />
  <row Id="18968" PostTypeId="1" CreationDate="2020-01-14T12:32:20.137" Score="1" ViewCount="150" Body="&lt;p&gt;It is claimed by some that the reason for gaps in chains of volcanoes generated by plate subduction is that some parts of the plate dive deep into the mantle and generate magma plumes, while other parts of the plate continue in an almost horizontal direction and therefore don't create magma plumes, hence the lack of volcanoes. Where one part of a plate continues almost horizontally while an adjacent section is driven down into the mantle, wouldn't that cause a violent fracture of the plate, and if not, why not? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Push a sheet of cardboard along a table top so that the leading edge of the cardboard overlaps the edge of the table, then grab a bit of cardboard and force it to descend. It will either carry the rest of the cardboard down with it, or it will break. I know that plates are not made of cardboard, but that's the best analogy I could think of to illustrate the principle. A similar fracture in an oceanic plate would surely be quite violent.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-16T13:39:19.423" Title="How Can Adjacent Parts of an Oceanic Plate be Subducted in Different Directions?" Tags="|volcanology|plate-tectonics|earthquakes|magma-plumes|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18969" PostTypeId="2" ParentId="18968" CreationDate="2020-01-14T16:58:44.993" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Where one part of a plate continues almost horizontally while an adjacent section is driven down into the mantle, wouldn't that cause a violent fracture of the plate, and if not, why not? &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In case of the Nazca plate probably not because that is still warm and partly ductile (see the linked work in the other thread). Also, these cracks and deformations happen as the plate subducts, they don't displace a huge pile of material in one single event, like does a movement along a transform crack (e.g. San Andreas), or a &quot;megathrust&quot; earthquake along a subduction zone. A &lt;a href=&quot;https://www.nature.com/articles/s41561-018-0229-y.epdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;whole plate breaking along the bend line&lt;/a&gt; otoh can trigger catastrophic earthquakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I could not find a specific work that deals with the interface between a steep and a shallow subduction, but a &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007TC002175&quot; rel=&quot;nofollow noreferrer&quot;&gt;work discussing&lt;/a&gt; the dynamics of the Nazca plate subduction. They state that the ridges (being warm and buoyant) are subducted because of the movement of the adjacent slabs (dragged along so to say), and becaue of global plate motion, meaning the earth can't change volume so some parts just must give way for emerging parts elsewhere (Atlantic opening is mentioned). There is a map of epicenters of (generally low mag) earthquakes (and links to other work) along the Nazca subduction as well as above the flat segments, suggesting that the cause there is the greater friction. The oceanic crust, being quite topographic, is flattened while being pushed or drawn under the continent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earthquakes because of segmenting as asked in the OP aren't mentioned specifically.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I find it interesting, maybe someone else knows more.&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-16T13:39:19.423" LastActivityDate="2020-01-16T13:39:19.423" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18970" PostTypeId="2" ParentId="18174" CreationDate="2020-01-15T00:37:22.907" Score="3" Body="&lt;p&gt;Urban areas, where most snow clearing is done, are &lt;a href=&quot;https://en.wikipedia.org/wiki/Urban_heat_island&quot; rel=&quot;nofollow noreferrer&quot;&gt;heat islands&lt;/a&gt; already, so it would be tough to disentangle the effect of clearing snow off roads.  Whitewashing black asphalt is one of the &lt;a href=&quot;https://e360.yale.edu/features/can-we-turn-down-the-temperature-on-urban-heat-islands&quot; rel=&quot;nofollow noreferrer&quot;&gt;strategies being tried&lt;/a&gt; to &lt;a href=&quot;https://www.epa.gov/heat-islands/heat-island-cooling-strategies&quot; rel=&quot;nofollow noreferrer&quot;&gt;reduce the heat&lt;/a&gt; effect in the summer, though, and black asphalt is &lt;a href=&quot;https://science.howstuffworks.com/environmental/green-science/urban-heat-island2.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;seen as a big factor&lt;/a&gt; in heat islands, so it seems reasonable that exposing black pavement in winter would also have some impact, but detailed studies so far have mostly focussed on deadly summer heat, not winter effects. &lt;/p&gt;&#xA;" OwnerUserId="8062" LastActivityDate="2020-01-15T00:37:22.907" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18971" PostTypeId="2" ParentId="18890" CreationDate="2020-01-15T09:59:39.217" Score="3" Body="&lt;p&gt;I would say that the reason is because human civilisation, and particularly agricultural practices, evolved and are adapted to the pre-industrial climate.  This means that any substantial change in the climate will require changes in our civilisation and agriculture, which inevitably has a cost.  So the reason that most of the changes are negative is not to do with the science, but to do with us.&lt;/p&gt;&#xA;" OwnerUserId="624" LastActivityDate="2020-01-15T09:59:39.217" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18972" PostTypeId="1" AcceptedAnswerId="18973" CreationDate="2020-01-15T10:32:16.200" Score="2" ViewCount="271" Body="&lt;p&gt;What is &quot;sheltered site&quot; (as opposed to &quot;exposed site&quot;)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's used in context of location of trees in bumpy ground areas and weather damage.&lt;/p&gt;&#xA;" OwnerUserId="18721" LastEditorUserId="18721" LastEditDate="2020-01-15T10:46:42.563" LastActivityDate="2020-01-17T18:27:48.710" Title="What is &quot;sheltered site&quot; (as opposed to &quot;exposed site&quot;)?" Tags="|geography|forest|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18973" PostTypeId="2" ParentId="18972" CreationDate="2020-01-15T10:58:06.197" Score="3" Body="&lt;p&gt;Depends on the context. Examples can be: In depressions instead of lonely on the plain, inside of the forest instead of at the edge, along a river bank or lakeside instead of on dry ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or, in short: exposed to wind &amp;amp; weather instead of sheltered from the rigour.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also depends on the tree. Some pioneer trees can grow individually in adverse conditions, others like it in groups and warm and wet.&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastActivityDate="2020-01-15T10:58:06.197" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18974" PostTypeId="1" CreationDate="2020-01-15T11:30:55.107" Score="2" ViewCount="574" Body="&lt;p&gt;Trees: What does &quot;highly tapering stem&quot; mean?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Taper is a function measuring steepness of change in crown diameter when height increases upwards.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But &quot;highly tapering&quot; (sometimes also &quot;high-degree of taper&quot;)? Is it &quot;a large change in taper&quot; (large steepness) or a &quot;fine change in taper over a long height&quot; (low steepness, but high fineness of change)?&lt;/p&gt;&#xA;" OwnerUserId="18721" LastEditorUserId="18721" LastEditDate="2020-01-15T13:05:57.487" LastActivityDate="2020-01-31T09:17:22.697" Title="Trees: What does &quot;highly tapering stem&quot; mean?" Tags="|forest|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18975" PostTypeId="2" ParentId="18974" CreationDate="2020-01-15T12:16:46.043" Score="-1" Body="&lt;p&gt;It means that the tree is thick at the base, but rapidly becomes thinner as it ascends. The use of &quot;stem&quot; is anomalous. An Englishman would speak of 'a highly tapering trunk'. Stem is used when referring to much smaller plants.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-15T12:16:46.043" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18976" PostTypeId="1" CreationDate="2020-01-15T14:21:58.440" Score="6" ViewCount="283" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Wa1LS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Wa1LS.jpg&quot; alt=&quot;piece of material from Mars&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The above is a magnified part of the original image below captured by the Curiosity rover on Mars on sol 1729 (June 17, 2017).&lt;br&gt;&#xA; From the added information with that raw image it can be estimated that the distance between the lens and the target was about 14 cm.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CzaxR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CzaxR.jpg&quot; alt=&quot;original image&quot;&gt;&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Below another image of the thin piece with surroundings in the sunshine.&lt;br&gt;&#xA;Click (or double click) on the image for magnification.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8D2eJ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8D2eJ.jpg&quot; alt=&quot;piece with surroundings&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Asking about the &lt;a href=&quot;https://space.stackexchange.com/questions/40837/what-likely-is-the-chemical-composition-of-the-thin-piece-of-material-on-the-sur&quot;&gt;chemical composition of this piece of material&lt;/a&gt; on &lt;strong&gt;space exploration SE&lt;/strong&gt;, it appeared from the answers that most likely it is CaSO&lt;span class=&quot;math-container&quot;&gt;$_4$&lt;/span&gt;, perhaps the hydrated form &lt;a href=&quot;https://en.wikipedia.org/wiki/Gypsum&quot; rel=&quot;nofollow noreferrer&quot;&gt;gypsum&lt;/a&gt;.&lt;br&gt;&#xA;I've seen many other &lt;a href=&quot;https://mars.nasa.gov/msl/multimedia/raw-images/&quot; rel=&quot;nofollow noreferrer&quot;&gt;raw images&lt;/a&gt; from Mars, but not anything like this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What could this thin piece of material be, does it resemble anything on Earth ?&lt;/p&gt;&#xA;" OwnerUserId="12903" LastEditorUserId="12903" LastEditDate="2020-01-17T17:10:59.057" LastActivityDate="2020-01-17T23:33:13.333" Title="Considering the thin piece of material on the surface of Mars in the image below, is there anything like it on Earth?" Tags="|geology|geochemistry|mars|" AnswerCount="2" CommentCount="13" ContentLicense="CC BY-SA 4.0" />
  <row Id="18978" PostTypeId="2" ParentId="18976" CreationDate="2020-01-15T17:52:44.703" Score="3" Body="&lt;p&gt;What you can see in the bottom picture is sandstone/mudstone/claystone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you look at the bottom picture top right you can see a thin rock that has split off, this is how a rock splits after it has been heated and then suddenly gets cooled down as it does on Mars when the Sun goes down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On Earth the change in temperature is too slow for this to happen in nature, but you can see this if a fire has been burning on top of a rock/stone and it has been rapidly cooled down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is how mining was done before explosives where invented, heating up the rock until it is &quot;glowing&quot; hot and then throwing water on the rock to suddenly cool it down so it fractures.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="12903" LastEditDate="2020-01-17T12:35:40.977" LastActivityDate="2020-01-17T12:35:40.977" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="18979" PostTypeId="1" CreationDate="2020-01-15T21:14:55.927" Score="3" ViewCount="435" Body="&lt;p&gt;I was listening to a geology podcast describing how sedimentary rock forms and later turns into metamorphic rock. As a river lays down sediment, the lower layers can eventually be several kilometers below ground, where heat and pressure are significant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How does this happen? Does the river bed get built higher and higher until the first layer of sediment is buried deeply, or does the bottom layer get pushed down into the earth? In other words, is the elevation of a given section of river increasing while this happens, or does it remain the same?&lt;/p&gt;&#xA;" OwnerUserId="18728" LastEditorUserId="18081" LastEditDate="2020-01-16T11:53:33.640" LastActivityDate="2020-01-18T20:15:00.920" Title="When sediments are deposited, do they sink into the earth?" Tags="|sedimentology|petrology|stratigraphy|metamorphism|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18980" PostTypeId="1" AcceptedAnswerId="18985" CreationDate="2020-01-15T23:26:41.157" Score="2" ViewCount="201" Body="&lt;p&gt;I read on &lt;a href=&quot;https://www.uexpress.com/ask-the-doctors/2018/1/17/no-matter-the-time-of-day&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.uexpress.com/ask-the-doctors/2018/1/17/no-matter-the-time-of-day&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;UVA maintains the same intensity all day, which makes dawn-to-dusk sunscreen use important&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Whereas on &lt;a href=&quot;https://weather.com/weather/hourbyhour/l/Lima+Lima+Province+Peru?placeId=4c3d66b0fe4de8cdf345929531e7f189818eb49d39eeee5dfe77efb594eb51fc&quot; rel=&quot;nofollow noreferrer&quot;&gt;weather.com&lt;/a&gt; I can see that the UV index, which mostly tracks the level of UVB, significantly varies throughout the day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I read that the UV index mostly tracks the level of UVB radiations on &lt;a href=&quot;https://en.wikipedia.org/wiki/Ultraviolet_index&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Ultraviolet_index&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Because of the way the UV index is calculated, it technically expresses the risk of developing sunburn, which is caused mostly by UVB radiation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Why is the level of UVA radiations on the earth surface the same throughout the daylight hours, while the level of UVB significantly varies?&lt;/p&gt;&#xA;" OwnerUserId="587" LastEditorUserId="587" LastEditDate="2020-01-15T23:49:03.713" LastActivityDate="2020-01-16T11:23:34.733" Title="Why is the level of UVA radiations on the earth surface the same throughout the day, while the level of UVB significantly varies?" Tags="|uv-light|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18981" PostTypeId="1" CreationDate="2020-01-16T02:27:26.970" Score="5" ViewCount="154" Body="&lt;p&gt;Anyone know of an existing dataset of areas below sea level? Vector extents would be ideal. Doesn't need to be super detailed for my purposes, but it would be good if it included all areas (e.g. over-estimate is better than under-estimate).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is a &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_places_on_land_with_elevations_below_sea_level&quot; rel=&quot;noreferrer&quot;&gt;List of places on land with elevations below sea level on Wikipedia&lt;/a&gt;, which looks like it's fairly complete, but finding the extents of the below-sea-level area for each of those locations is not likely to be simple.&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2021-01-08T15:44:06.667" Title="Global areas below sea level dataset?" Tags="|sea-level|open-data|land|landscape|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18982" PostTypeId="2" ParentId="18981" CreationDate="2020-01-16T08:45:02.490" Score="8" Body="&lt;p&gt;You could try building one using a global Digital Elevation Model. There are several freely available like &lt;a href=&quot;https://geoservice.dlr.de/web/dataguide/tdm90/&quot; rel=&quot;nofollow noreferrer&quot;&gt;TanDEM-X&lt;/a&gt;, &lt;a href=&quot;https://www2.jpl.nasa.gov/srtm/&quot; rel=&quot;nofollow noreferrer&quot;&gt;SRTM&lt;/a&gt;, or &lt;a href=&quot;https://lpdaac.usgs.gov/news/nasa-and-meti-release-aster-global-dem-version-3/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ASTER GDEM&lt;/a&gt;. You'd have to look for all the pixels containing a negative value. Adjacent negative pixels would give you connected regions below sea level, and you could easily estimate their area just by multiplying the number of pixels of a region by the area of one pixel.&lt;/p&gt;&#xA;&lt;p&gt;I'm not saying it would be easy. The main challenge would probably be that some regions would be split across several tiles.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;An update on this. I spent a couple hours trying this as an exercise. I downloaded three tiles from the ASTER global DEM centered around Badwater Basin (Death Valley, USA), one of the regions in the Wikipedia list. I wrote a small (~20 lines) Matlab script that does the following:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Binarization of the images, so that every pixel above sea level is set to 0 (black) and every pixel below sea level is set to 1 (white).&lt;/li&gt;&#xA;&lt;li&gt;Concatenation of the three arrays in order to have only one image for the next step (I manually added a fourth, all black array for the sake of dimension consistency).&lt;/li&gt;&#xA;&lt;li&gt;With a binary image, Matlab has a useful function called &lt;code&gt;regionprops&lt;/code&gt; that finds all connected regions and returns their properties, such as their area (as a number of pixel).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Here is the result:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Xbo04.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Xbo04.png&quot; alt=&quot;Badland_Basin_black_and_white&quot; /&gt;&lt;/a&gt;&#xA;I'm pretty happy with it, as it looks very similar to the yellow area labelled &amp;quot;below sea level&amp;quot; on &lt;a href=&quot;https://web.archive.org/web/20071224063142/http://geology.wr.usgs.gov/parks/deva/ftbad2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this USGS map&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/G9iwo.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G9iwo.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now, how does it translate in terms of area? According to Matlab, the white region has an area of 1 236 989 pixels. Each pixel being approximately 30x30 meters, it yields a below sea level area of 1 113 km&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt;. The only figure I could find online is &lt;a href=&quot;https://www.britannica.com/place/Death-Valley&quot; rel=&quot;nofollow noreferrer&quot;&gt;1 425 km&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt;&lt;/a&gt; from Encyclopedia Britannica, with no source. But for me that's close enough to have confidence in my estimate!&lt;/p&gt;&#xA;&lt;p&gt;Some shortcomings:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;I knew exactly which tiles contained this particular below sea level region. If you were to go through all tiles (almost 23 000!), you'd have to figure a way to detect when a region is split across multiple tiles in order to reconstruct the region by concatenation. Doesn't seem that hard, but not trivial.&lt;/li&gt;&#xA;&lt;li&gt;I did not take into account the fact that there is a one pixel overlap between adjacent tiles (it should not change change the result much).&lt;/li&gt;&#xA;&lt;li&gt;I did not take into account the fact that pixel size actually vary (the resolution is one arc second, which is ~30 meters at the equator but changes with latitude).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2021-01-08T15:44:06.667" LastActivityDate="2021-01-08T15:44:06.667" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="18983" PostTypeId="2" ParentId="18979" CreationDate="2020-01-16T08:54:14.623" Score="4" Body="&lt;p&gt;The rivers transport most of the sediments to the coastal or marine basins where they accumulate. An exception are lacustrine basins, but most of world rivers sediments are deposited on shallow or deep marine basins.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the stack of sediments is large, &lt;a href=&quot;http://www.geosci.usyd.edu.au/users/prey/ACSGT/EReports/eR.2003/GroupD/Report2/web%20pages/Listric_Faults.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;listric faults&lt;/a&gt; develop, and the bottom layer get pushed down into the earth. This process is called &lt;a href=&quot;https://www.britannica.com/science/subsidence&quot; rel=&quot;nofollow noreferrer&quot;&gt;subsidence&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Ny1SN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ny1SN.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://www.apg-pro.com/services-upstream-petroleum-industry-geology/&quot; rel=&quot;nofollow noreferrer&quot;&gt;apg-pro.com&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As new sediments accumulate, faults are activated and the basin becomes larger. Elevation of a given section of the basin remains approximately the same, as this is a slow process. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case the bottom layer reaches great depth, burial metamorphism can develop:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Burial Metamorphism: occurs when sedimentary rocks that had undergone &lt;a href=&quot;https://en.wikipedia.org/wiki/Diagenesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;diagenesis&lt;/a&gt; are buried&#xA;  even deeper. Diagenesis grades into burial metamorphism, a relatively&#xA;  mild type of metamorphism resulting from the heat and pressure exerted&#xA;  by overlying sediments and sedimentary rocks. Although partial&#xA;  alteration of the mineralogy and texture may occur, bedding and other&#xA;  sedimentary structures are usually preserved&quot;.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: &lt;a href=&quot;https://uh.edu/~geos6g/1330/meta.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;uh.edu&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user18590" LastEditorDisplayName="user18590" LastEditDate="2020-01-16T13:43:35.363" LastActivityDate="2020-01-16T13:43:35.363" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="18984" PostTypeId="2" ParentId="18979" CreationDate="2020-01-16T10:27:42.513" Score="2" Body="&lt;p&gt;No, sediments do not sink into the earth because they are too light. They stay on the surface and over very long times they form the continents. But they can get buried under many km of other sediments as parts of the crust they're on subsides or is pushed over other parts. Thus they can get into pressure/temperatue conditions where diagenesis (see other answer) or &lt;a href=&quot;https://en.wikipedia.org/wiki/Metamorphism&quot; rel=&quot;nofollow noreferrer&quot;&gt;metamorphism&lt;/a&gt; alter them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On a very general level, plate tectonics keep the crust in motion. It can cause the surface to rise in some places and subside in others. When it rises it forms mountains, for example in an &lt;a href=&quot;https://en.wikipedia.org/wiki/Orogeny&quot; rel=&quot;nofollow noreferrer&quot;&gt;orogeny&lt;/a&gt; over a subduction zone or when two continents collide and the crust between them is forced upwards. &lt;a href=&quot;https://www.scientificamerican.com/article/weathering-rocks/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weathering&lt;/a&gt; and &lt;a href=&quot;https://www.nationalgeographic.org/encyclopedia/erosion/&quot; rel=&quot;nofollow noreferrer&quot;&gt;erosion&lt;/a&gt; starts in the rising zones, and they produce a lot of sediments which are transported by water, wind and gravity down into lower areas. Otoh, where the crust is stretched or subsides, e.g. in &lt;a href=&quot;https://en.wikipedia.org/wiki/Graben&quot; rel=&quot;nofollow noreferrer&quot;&gt;Graben&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Foreland_basin&quot; rel=&quot;nofollow noreferrer&quot;&gt;basins&lt;/a&gt;, the sediments accumulate, layer by layer, and tell the long story of what has happened in the past (see @Universal_Learner's answer).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another, somewhat more exotic process that forms thick sediment packages, is the scraping off of marine sediments from a subducting plate to form an &lt;a href=&quot;https://en.wikipedia.org/wiki/Accretionary_wedge&quot; rel=&quot;nofollow noreferrer&quot;&gt;accretionary wedge&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These sediment packages can get many kilometers thick, the &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015TC004109&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pannonian basin&lt;/a&gt; holds the sediments of a mountain range in thicknesses between 1 and 5 km, &gt;6km in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Molasse_basin&quot; rel=&quot;nofollow noreferrer&quot;&gt;Molasse&lt;/a&gt; basin north of the alps, up to 16km in the &lt;a href=&quot;https://ui.adsabs.harvard.edu/abs/2005IJEaS..94..732S/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;Upper Rhine Graben&lt;/a&gt;, where they can be altered metamoprhically (apart from contact or hydrothermal metamorphosis in regions with volcanism). Metamoprhic conditions (&quot;facies&quot;) can also be met in a continent-continent collision and the connected mountain ranges, like parts of the &lt;a href=&quot;https://www.geo.fu-berlin.de/en/v/geolearning/mountain_building/metamorphism/generation_types_metamorphism/collision_metamorphism/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Himalaya&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Rivers (i am not an expert in this and kindly ask for correction) do not rise above the surrounding (gravity is against it ;-)), but they change shape and appearance with the slope and sediment load. For example from &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Alluvial_fan&quot; rel=&quot;nofollow noreferrer&quot;&gt;alluvial fans&lt;/a&gt;&quot; at the foot of a mountain over &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Braided_river&quot; rel=&quot;nofollow noreferrer&quot;&gt;braided rivers&lt;/a&gt;&quot; in mountainous areas where slope is still high and grain size big over &lt;a href=&quot;https://en.wikipedia.org/wiki/Meander&quot; rel=&quot;nofollow noreferrer&quot;&gt;meander&lt;/a&gt; patterns in low slope areas with small grain size to &lt;a href=&quot;https://en.wikipedia.org/wiki/River_delta&quot; rel=&quot;nofollow noreferrer&quot;&gt;deltas&lt;/a&gt; filled with mud and clay.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When a river reaches an area where it can't carry on because all around the land rises again, it can build a lake until it finds a new exit, or it simply fills up the area with its sediments.&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-16T15:22:07.517" LastActivityDate="2020-01-16T15:22:07.517" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18985" PostTypeId="2" ParentId="18980" CreationDate="2020-01-16T11:23:34.733" Score="1" Body="&lt;p&gt;UVA rays are very penetrating and are not weakened by the ozone layer, so are much the same throughout the day. UVB rays are of shorter wavelength, much less penetrating, and are weakened by passing through the atmosphere. At different times of day there are thicker or thinner layers of atmosphere to pass through. Near sunset, the UVB rays will be oblique, and therefore have a greater thickness of atmosphere to pass through, so will be consequently weakened. UVC rays are of even shorter wavelength and are mostly blocked by the ozone layer.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-16T11:23:34.733" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18986" PostTypeId="1" CreationDate="2020-01-16T17:56:18.547" Score="0" ViewCount="1714" Body="&lt;p&gt;The greenhouse effect analogy of global warming is that atmospheric carbon dioxide CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; absorbs some of the infrared radiation emitted by the Earth, and redirects a portion of that radiation back down to the Earth's surface, thereby heating the surface more than it would have done if that radiation had been able to escape into space. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Global warming is then simplistically explained to the general public by the idea that as atmospheric CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; concentrations rise, more infrared radiation is absorbed by CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; and re-emitted back down to Earth, causing increased heating of the Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, this explanation is not technically correct, because at present atmospheric CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; concentrations, just one kilometer of atmosphere is sufficient to fully absorb all the infrared radiation emitted by the Earth, at the wavelengths at which CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; absorbs. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Carbon dioxide absorbs infrared at the wavelengths of 2.7, 4.3 and 15 µm, and the CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; in the first kilometer of atmosphere alone is able to completely absorb all infrared at these wavelengths.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the infrared absorption process is already fully saturated, and thus further increases in atmospheric CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; will not lead to any additional absorption. This is why the simplistic explanation provided for the general public does not seem to be technically correct, even though it roughly outlines the idea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found one &lt;a href=&quot;http://clivebest.com/blog/?p=1169&quot; rel=&quot;nofollow noreferrer&quot;&gt;blog article&lt;/a&gt; by Clive Best that tries to explain the actual process behind CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;'s ability to cause global warming. Judging from that article, the actual process is more complex than the simple explanation provided for public consumption. However, I don't fully understand the explanation given in the article (and from what I did manage to understand, I am not sure if it is fully correct).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So I wonder if anyone here can provide an easy to understand explanation of the actual mechanism by which increased atmospheric CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; leads to global warming. Or perhaps if you know any good articles that explain it, please can you post the links.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried to find some info on the actual mechanism of global warming via Google, by using search terms such as &quot;mechanism of greenhouse effect in global warming&quot;, but was surprised to find very little information available. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also asked this question on physics.stackexchange.com &lt;a href=&quot;https://physics.stackexchange.com/questions/525177/can-anyone-explain-the-real-reason-why-co-2-increases-global-temperatures-not&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="18736" LastEditorUserId="725" LastEditDate="2020-04-21T10:47:38.360" LastActivityDate="2022-10-10T09:06:32.523" Title="Can anyone explain the reason why CO$_2$ increases global temperatures (not the simplistic greenhouse analogy provided for public consumption)?" Tags="|climate-change|carbon-cycle|greenhouse-gases|" AnswerCount="5" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="18987" PostTypeId="1" AcceptedAnswerId="19010" CreationDate="2020-01-16T22:40:02.827" Score="1" ViewCount="153" Body="&lt;p&gt;I need MERRA2 data with Temperature at 2m.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm checking on &lt;a href=&quot;https://disc.gsfc.nasa.gov/daac-bin/FTPSubset2.pl&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://disc.gsfc.nasa.gov/daac-bin/FTPSubset2.pl&lt;/a&gt; but I can't find this variable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Suggestions where I can find them? Or anyone that did have or has the same problem?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you for the help.&lt;/p&gt;&#xA;" OwnerUserId="17200" LastActivityDate="2020-01-18T18:05:28.637" Title="Temperature at 2 m MERRA2" Tags="|temperature|weather-forecasting|open-data|reanalysis|netcdf|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18989" PostTypeId="1" CreationDate="2020-01-17T03:57:12.897" Score="1" ViewCount="82" Body="&lt;p&gt;The planet has been warming for thousands of years. Human activity has accelerated the warming, but by how much? At some point in the future, without human intervention, the climate will have naturally reached the point it's at today. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;As of 2020, by how many years has human activity advanced the climate change clock?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there another good measure for Human vs Natural climate change?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This should be something that could be extrapolated from a good chart, but I haven't found a source.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I feel that this is not a duplicate because I'm asking a very specific question regarding the number of years. None of the similar questions or answers address this.&lt;/p&gt;&#xA;" OwnerUserId="18740" LastEditorUserId="18740" LastEditDate="2020-01-17T16:46:34.207" LastActivityDate="2020-01-17T16:46:34.207" Title="Climate change: Human vs Natural" Tags="|climate-change|climate|temperature|ice-age|" AnswerCount="0" CommentCount="5" ClosedDate="2020-01-17T15:35:26.470" ContentLicense="CC BY-SA 4.0" />
  <row Id="18990" PostTypeId="2" ParentId="18974" CreationDate="2020-01-17T08:52:44.110" Score="5" Body="&lt;p&gt;A &quot;highly tapering stem&quot; is simply that the trunk of the tree is less cylindrical and more conical in profile. It's a problem because while you may have a lot of timber &lt;em&gt;volume&lt;/em&gt; you don't have as much timber that is &lt;em&gt;usable&lt;/em&gt; because you'll end up with a higher proportion of sawmill waste.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm English and have a degree in forestry. Regardless of comments elsewhere, a &quot;highly tapering stem&quot; is perfectly good terminology, although I agree that it could be clearer. I would tend to say &quot;a high degree of tapering&quot; or a &quot;more tapered stem&quot; for clarity's sake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A full description of this can be found in &lt;a href=&quot;https://www.forestresearch.gov.uk/research/forest-mensuration-a-handbook-for-practitioners/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Forest Mensuration: a handbook for practitioners&lt;/a&gt; by Matthews and Mackie on page 114. (They refer to a tapering log, because they are discussing felled timber).&lt;/p&gt;&#xA;" OwnerUserId="18621" LastEditorUserId="18621" LastEditDate="2020-01-31T09:17:22.697" LastActivityDate="2020-01-31T09:17:22.697" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18991" PostTypeId="2" ParentId="18986" CreationDate="2020-01-17T15:10:02.720" Score="13" Body="&lt;p&gt;Borrowing an explanation from one of my other &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7502/is-there-any-experiment-to-prove-that-co2-with-the-atmosphere-concentration-can/7522#7522&quot;&gt;answers&lt;/a&gt;, the basic mechanism of the greenhouse effect is roughly as follows (note this is also a simplified model)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Earth is in (to all intents and purposes) a vacuum, so it can only&#xA;  gain or lose heat via radiation. The sun emits most of its radiation&#xA;  at visible and UV wavelengths. The Earth's atmosphere is fairly&#xA;  transparent at these wavelengths and so the Sun's radiation mostly&#xA;  passes through it and hits the surface. Some of this radiation&#xA;  (determined by the Earth's albedo) is reflected from the surface back&#xA;  out into space, but the rest is absorbed by the surface, which causes&#xA;  the surface to be warm. The surface loses heat by radiating in&#xA;  infra-red wavelengths. Greenhouse gases absorb some of the IR&#xA;  radiation, which causes the atmosphere to warm up (the GHG molecules&#xA;  transfer some of this heat to non-greenhouse gasses by collisions, but&#xA;  heat is also transferred upwards by convection). The warm atmosphere&#xA;  re-radiates some of this energy both upwards into space and downwards&#xA;  back to the surface. The part that is radiated downwards is also known&#xA;  as &quot;back-radiation&quot; (and is directly observable). Now the important&#xA;  factor is not the amount of outbound IR radiated from the surface that&#xA;  is absorbed, but the altitude at which there are not enough greenhouse&#xA;  gases above to absorb the IR radiated upwards from that layer, so that&#xA;  it can escape out into space. The lapse rate means that the&#xA;  temperature of the atmosphere decreases with increasing height. This&#xA;  means that the more CO2 we put into the atmosphere, the higher this&#xA;  emitting layer becomes, and the colder it is. As the amount of IR&#xA;  radiated depends on the temperature of this layer, if this height&#xA;  increases then the amount of IR radiated from the planet falls,&#xA;  leading to an energy imbalance, with the planet absorbing more of the&#xA;  sun's radiation than it emits as IR, and so the planet warms up. This&#xA;  continues until the radiating layer warms up enough for the outbound&#xA;  IR to be in balance with the incoming radiation from the sun. So the&#xA;  more CO2, the warmer the mean surface temperature, all things being&#xA;  otherwise equal.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Thus it is irrelevant that most IR emitted by the surface is absorbed by the atmosphere, it is the height from which IR is &lt;strong&gt;not&lt;/strong&gt; absorbed that matters.  If it is colder than the surface, it will emit less IR than the surface is emitting and hence less energy is radiated into space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a more detailed explanation of why absorption at the surface is of little relevance, see this RealClimate &lt;a href=&quot;http://www.realclimate.org/index.php/archives/2007/06/a-saturated-gassy-argument/&quot; rel=&quot;noreferrer&quot;&gt;article&lt;/a&gt; by Spencer Weart.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just to add a historical note, this explanation goes back at least as far as Ekholm's paper of 1901 &quot;On The Variations Of The Climate Of The Geological And Historical Past And Their Causes&quot;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The atmosphere plays a very important part of a double character as to the&#xA;  temperature at the earth’s surface, of which the one was&#xA;  first pointed out by Fourier, the other by Tyndall. Firstly, the&#xA;  atmosphere may act like the glass of a green-house, letting through&#xA;  the light rays of the sun relatively easily, and absorbing a great&#xA;  part of the dark rays emitted from the ground, and it thereby may&#xA;  raise the mean temperature of the earth’s surface. Secondly, the&#xA;  atmosphere acts as a heat store placed between the relatively warm&#xA;  ground and the cold space, and thereby lessens in a high degree the&#xA;  annual, diurnal, and local variations of the temperature.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;There are two qualities of the atmosphere that produce these effects. The &#xA;  one is that the temperature of the atmosphere generally&#xA;  decreases with the height above the ground or the sea-level, owing&#xA;  partly to the dynamical heating of descending air currents and the&#xA;  dynamical cooling of ascending ones, as is explained in the mechanical&#xA;  theory of heat. The other is that the atmosphere, absorbing but little&#xA;  of the insolation and the most of the radiation from the ground,&#xA;  receives a considerable part of its heat store from the ground by&#xA;  means of radiation, contact, convection, and conduction, whereas the&#xA;  earth’s surface is heated principally by direct radiation from the sun&#xA;  through the transparent air.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;It follows from this that the radiation from the earth into space does &#xA;  not go on directly from the ground, but on the average from a&#xA;  layer of the atmosphere having a considerable height above sea-level.&#xA;  The height of that layer depends on the thermal quality of the&#xA;  atmosphere, and will vary with that quality. The greater is the&#xA;  absorbing power of the air for heat rays emitted from the ground, the&#xA;  higher will that layer be, But the higher the layer, the lower is its&#xA;  temperature relatively to that of the ground ; and as the radiation&#xA;  from the layer into space is the less the lower its temperature is, it&#xA;  follows that the ground will be hotter the higher the radiating layer&#xA;  is.”&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://dx.doi.org/doi:10.1002/qj.49702711702&quot; rel=&quot;noreferrer&quot;&gt; [Ekholm&lt;/a&gt;, 1901, p19-20]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(h/t Steve Easterbrook's blog &lt;a href=&quot;https://www.easterbrook.ca/steve/2015/08/who-first-coined-the-term-greenhouse-effect/&quot; rel=&quot;noreferrer&quot;&gt;article&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="624" LastEditorUserId="624" LastEditDate="2020-01-17T16:19:01.647" LastActivityDate="2020-01-17T16:19:01.647" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="18992" PostTypeId="2" ParentId="18932" CreationDate="2020-01-17T15:12:46.550" Score="2" Body="&lt;p&gt;One of the most widely used index to quantify the drought events is the standardized precipitation index (SPI) and it is actually based on precipitation time series only. &#xA;The index is used, among others, also by the &lt;a href=&quot;https://www.cpc.ncep.noaa.gov/products/Drought/Monitoring/spi.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FuurM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FuurM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll borrow the description of the index from a scientific article (&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S095937801830253X&quot; rel=&quot;nofollow noreferrer&quot;&gt;Farinosi et al 2018&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Standardized precipitation Index (&lt;a href=&quot;https://climate.colostate.edu/pdfs/relationshipofdroughtfrequency.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;McKee et al., 1993&lt;/a&gt;)&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The index is a measure expressed in standard deviation units of the&#xA;  variation of the precipitation of a specific number of months respect&#xA;  to the long run average (&lt;a href=&quot;https://library.wmo.int/index.php?lvl=notice_display&amp;amp;id=13682#.XiHLa4h7laQ&quot; rel=&quot;nofollow noreferrer&quot;&gt;WMO, 2012&lt;/a&gt;). The number of months based on&#xA;  which the SPI could be calculated usually varies between 3 and 48&#xA;  months. Shorter time scales SPI is considered a good indicator of&#xA;  variations of soil moisture, while on longer scales (up to 24 months),&#xA;  it could be associated with groundwater or reservoir levels variation&#xA;  (&lt;a href=&quot;https://library.wmo.int/index.php?lvl=notice_display&amp;amp;id=13682#.XiHLa4h7laQ&quot; rel=&quot;nofollow noreferrer&quot;&gt;WMO, 2012&lt;/a&gt;). That for, a shorter SPI (3 months) is often utilized to&#xA;  detect meteorological droughts; a medium SPI (6 months) is usually&#xA;  associated with agricultural droughts; a longer SPI (12–24 months) is&#xA;  associated with hydrological droughts. SPI was calculated using the R&#xA;  package SPEI (&lt;a href=&quot;https://cran.r-project.org/web/packages/SPEI/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Beguería and Vicente-Serrano, 2014&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Usually the minimum requirements to have a robust estimation of the SPI is to have a precipitation time series of at least 30 years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could use the SPI to quantify the number of &quot;droughts&quot; (choosing a threshold under which you define the event - for instance see &lt;a href=&quot;https://images.app.goo.gl/HJrJTzaDTmyQUrNp8&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;) in a period for your area of interest and then aggregate the number of &quot;meteorological&quot;, &quot;agricultural&quot;, and &quot;hydrological&quot; droughts. &lt;/p&gt;&#xA;" OwnerUserId="8087" LastActivityDate="2020-01-17T15:12:46.550" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18993" PostTypeId="1" CreationDate="2020-01-17T16:01:30.667" Score="1" ViewCount="68" Body="&lt;p&gt;Since in 100 years, the global warming potential (GWP) of methane is 28-36, what will be the GWP in 1 day time frame?&#xA;Can it be calculated that way?&lt;/p&gt;&#xA;" OwnerUserId="18651" LastEditorUserId="18081" LastEditDate="2020-01-17T16:12:33.767" LastActivityDate="2020-01-17T18:37:52.537" Title="What is the global warming potential (GWP) of any gas over a 1 day time frame?" Tags="|climate-change|greenhouse-gases|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18994" PostTypeId="2" ParentId="18964" CreationDate="2020-01-17T17:22:57.193" Score="-7" Body="&lt;p&gt;It isn't Co2 (sorry I know that's likely unpopular for most to hear), it's (primarily) the sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Real quick, rising Co2 doesn't cause wildfires, trees love Co2, visit a greenhouse. Wildfires are a result of (bleep holes) running around lighting fires. Look it up, nearly 200 people arrested so far in Australia for arson.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ocean rise prediction data (focused on Co2) fails to account for increased plant intake due to plant growth explosion. Similarly, population reduction doesn't account for the 12 gallons of water that makes up an average male. Reduce population by 1 million average men, increase water levels by approx 12 million gallons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The ice was always supposed to melt, it's a byproduct of a catastrophe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the long answer to your point is technically &quot;classified&quot; by the U.S. military and a secret. It was part of my training in the USAF, couldn't do my job unless they told me. What's classified is less the information but more our comprehension of it. Foreign nations know of it, they just don't have the big picture. Once you know, Climate Change is literally a hoax as it's currently being peddled.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is one entity that monitors the real source of our &quot;Climate Change&quot; &lt;a href=&quot;https://www.swpc.noaa.gov/products/planetary-k-index&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This site also has some good info; &lt;a href=&quot;https://web.ua.es/docivis/magnet/earths_magnetic_field2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth's Electromagnetic Field&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My previous source was NORAD, I'm retired now, can't access it so, NOAA is the closest thing I've found publically available. We referred to it as &quot;Geo-Planetary Index&quot;, it was/is monitored by the &quot;minute&quot; because it's that critical to success of the military's mission.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know if politicians know the truth but some manufacturers clearly do. One example; &lt;a href=&quot;https://en.wikipedia.org/wiki/ECC_memory&quot; rel=&quot;nofollow noreferrer&quot;&gt;ECC_memory&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not a fan of using Wiki however, the author of this excerpt from the above link knows what I know; &quot;research has shown that the majority of one-off soft errors in DRAM chips occur as a result of background radiation, chiefly neutrons from cosmic ray secondaries, which may change the contents of one or more memory cells or interfere with the circuitry used to read or write to them.[3] Hence, the error rates increase rapidly with rising altitude; for example, compared to sea level, the rate of neutron flux is 3.5 times higher at 1.5 km and 300 times higher at 10–12 km (the cruising altitude of commercial airplanes).[4] As a result, systems operating at high altitudes require special provision for reliability.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the public really wants to have an appreciable effect on the temperature, find a way to make the roadways, solar panels white/reflective. Plant more green things...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit/Update: Just keep this in mind, Co2 not being the cause isn't my &quot;opinion&quot;. It doesn't matter if you have a PhD in &quot;Climate Studies&quot;, it doesn't change reality.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More things to consider:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How many colliders are on the planet? (Hint: 40% are underground/classified i.e. don't exist, why?)&#xA;What alternative things are they used for beyond scientific study?&#xA;When do they fire them?&#xA;Where are they geo located, what's unique about their placement?&#xA;Why are they often fired simultaneously on opposite sides of the globe?&#xA;Who controls them?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Answers those questions, you'll realize &quot;they&quot; know it's not Co2, and you'll know it too.&lt;/p&gt;&#xA;" OwnerUserId="18745" LastEditorUserId="18745" LastEditDate="2020-01-18T15:38:36.327" LastActivityDate="2020-01-18T15:38:36.327" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="18996" PostTypeId="2" ParentId="18993" CreationDate="2020-01-17T18:21:09.903" Score="1" Body="&lt;p&gt;It can, but it's not very helpful. A large number of gasses (methane being one) decompose relatively quickly in the atmosphere to form other compounds. A longer time horizon means you capture all of that change in the metric (as compared to CO2), while if you did it for a day you'd end up with a figure that only really made sense for that day. The details of how it's calculated and why the time horizons are where they are is in the &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/07/WGI_AR5.Chap_.8_SM.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC AR5 WG1 CH8 technical supplement&lt;/a&gt; (8.SM.11.1 Equations for the Global Warming Potential)&lt;/p&gt;&#xA;" OwnerUserId="18621" LastEditorUserId="5282" LastEditDate="2020-01-17T18:37:52.537" LastActivityDate="2020-01-17T18:37:52.537" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="18997" PostTypeId="2" ParentId="18972" CreationDate="2020-01-17T18:27:48.710" Score="2" Body="&lt;p&gt;It's basically a (rough) description of the relative wind speed on the site compared to the local average. If a site is sheltered, it will typically experience: lower wind speeds, &#xA; potentially warmer mean temperatures, and (in temperate zones) a lower risk of frost (although some sites may actually have an &lt;em&gt;increase&lt;/em&gt; due to catabatic airflow: &quot;frost hollows&quot;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Exposed sites are the reverse, higher windspeed, more extreme weather conditions.&lt;/p&gt;&#xA;" OwnerUserId="18621" LastActivityDate="2020-01-17T18:27:48.710" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18998" PostTypeId="1" CreationDate="2020-01-17T19:26:20.947" Score="2" ViewCount="65" Body="&lt;p&gt;I live in Kingston, Ontario (The Limestone City). I have always been fascinated by the different thicknesses of strata in the exposed formations. I am wondering if there is any quick and fast rule of thumb as to how long it takes to form a limestone strata or layer. 1&quot; (2.5cm) over 10 000 years? Over 100 000 years? Longer? I realize that there are many variables involved - depth of water, temperature etc. So if I look at a meter thick layer, can I tell, generally speaking, how long it took to form that layer.&#xA;Thanks in advance&lt;/p&gt;&#xA;" OwnerUserId="18750" LastActivityDate="2020-01-17T23:37:40.250" Title="Limestone formation" Tags="|limestone|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="18999" PostTypeId="2" ParentId="18998" CreationDate="2020-01-17T19:55:13.040" Score="1" Body="&lt;p&gt;There is no general rule.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Depositon of limestone is the outcome of biologic activity and that depends on climate cycles. There are a few special cases where it is thought that &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles&quot; rel=&quot;nofollow noreferrer&quot;&gt;Milankovitch cycles&lt;/a&gt; have played a role in the building of alternating limestone layers. Those are climate cycles induced by oscillations in earth's orbital parameters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An example is the Upper Jurassic in SW Germany, and possibly the French Jura and its continuation in the North American East. &lt;a href=&quot;http://kanalmusik.de/wordpress%202/wp-content/uploads/DSC_0661.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Random foto&lt;/a&gt;. The cycles there are long term (40ky or 100ky) and the layers are 10 to 80cm thick. &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0037073802003792&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/abs/pii/S0037073802003792&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other examples for Milankovitch cycles in the sediment record exist, e.g. in the &lt;a href=&quot;https://www.nature.com/articles/ncomms3452&quot; rel=&quot;nofollow noreferrer&quot;&gt;Permian&lt;/a&gt;, and surely more.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know about the conditions in your area. A brief search reveals that the limestone is Ordovician, and part of a unit named Black River Group. Maybe you can find specific publications, analyses of trace or other indicative fossils, if it is not too mangled ... idk.&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-17T23:37:40.250" LastActivityDate="2020-01-17T23:37:40.250" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19000" PostTypeId="2" ParentId="18976" CreationDate="2020-01-17T23:24:57.790" Score="2" Body="&lt;p&gt;If you enlarge the picture and follow a line at 1 o'clock from the weirdly shaped piece in question, a few feet away from it at the back of an imaginary 'man's head' rock, you will see a similar convoluted piece.  Now follow a line at 10 o'clock from our original specimen, and also a few feet away is a longer,straighter piece in the process of eroding from the rock. Nearby are more pieces eroding.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems to me that there were cracks or voids in the sandstone/mudstone into which a harder intrusion has been introduced. As the rock erodes, which is more slowly on Mars than on Earth because of the lack of wind and rain, these intrusions are eroding out and sometimes end up lying on the surface. As to the nature of the harder rock which forms the intrusions, I couldn't say. Perhaps someone else will have an idea. Is there anything like it on Earth? Probably, because most things on Mars have their counterparts on Earth, but I couldn't tell you where to look for these strangely shaped rocks.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2020-01-17T23:33:13.333" LastActivityDate="2020-01-17T23:33:13.333" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19001" PostTypeId="1" AcceptedAnswerId="19015" CreationDate="2020-01-18T02:56:46.260" Score="7" ViewCount="5767" Body="&lt;p&gt;Hello Earth Science Community,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am a beginner Python programmer trying to plot a single time step of 10m surface wind data I grabbed from the ECMWF ERA5 reanalysis single level dataset in Python 3.8.1 on my mac (Mac OS Mojave 10.14.6). I am having some trouble with the density of the wind vectors on my basemap plot, as the resulting plot from my code produces a near black screen. Below is the code I am working on. Just as a note, the plot also displays mean sea level pressure from one time step and I have been able to plot this successfully.&lt;/p&gt;&#xA;&#xA;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;import pygrib&#xA;import numpy as np&#xA;import matplotlib.pyplot as plt&#xA;from mpl_toolkits.basemap import Basemap&#xA;from mpl_toolkits.basemap import shiftgrid&#xA;#---------------------------------------------------------------------------------------------&#xA;#Helpful links where I found much of this code&#xA;#https://confluence.ecmwf.int/display/CKB/How+to+plot+GRIB+files+with+Python+and+matplotlib&#xA;#https://earthscience.stackexchange.com/questions/7012/plotting-wind-barbs-in-python&#xA;#-----------------------------------------------------------------------------------------&#xA;plt.clf()&#xA;fig = plt.figure(figsize = (10,10))&#xA;#---------------------------------------------------------------------------------------------&#xA;#Set lat/lon coordinates for basemap projection (default projection = cylindrical equadistant)&#xA;lllon = -170&#xA;lllat = 10&#xA;urlon = -110&#xA;urlat = 61&#xA;&#xA;#set lat/lon coordinates as well as plotting interval for drawing lat/lon as axis of plot&#xA;latmin=0&#xA;latmax=70&#xA;lonmin=-180&#xA;lonmax=-100&#xA;latinterval=20&#xA;loninterval=20&#xA;#---------------------------------------------------------------------------------------------&#xA;#create basemap and add some geo content to create a good starting point for plotting data&#xA;bmap = Basemap(llcrnrlon=lllon, llcrnrlat=lllat, urcrnrlon=urlon, urcrnrlat=urlat, resolution='f',epsg=3311)&#xA;bmap.drawcoastlines(linewidth=2,zorder=1)&#xA;bmap.drawstates(linewidth=2, zorder=1)&#xA;bmap.drawcountries(linewidth=2,zorder=1)&#xA;bmap.drawlsmask(land_color='white',ocean_color='white',lakes='false',resolution='f')&#xA;bmap.drawparallels(np.arange(latmin, latmax, latinterval), labels= [1,0,0,0],color='k',textcolor='k',linewidth = 2, fontsize=14)&#xA;bmap.drawmeridians(np.arange(lonmin, lonmax, loninterval), labels=[0,0,0,1],color='k',textcolor='k',linewidth = 2, fontsize=14)&#xA;#---------------------------------------------------------------------------------------------&#xA;#Read ERA5 GRIB file and Grab MSLP values&#xA;file = 'download.grib'&#xA;grbs = pygrib.open(file) &#xA;grb_mslp  = grbs.select()[2] #MSLP for 2012-03-26 @00UTC&#xA;data = grb_mslp.values #MSLP values in Pa&#xA;#---------------------------------------------------------------------------------------------&#xA;#Set up plotting parameters lons &amp;amp; lats. Shift lons so projection is -180 to 180 (not 0-360)&#xA;&#xA;#Create evenly spaced lons using first to last grid point. int(grb[Ni]) = 1440 (360/0.25)&#xA;lons = np.linspace(float(grb_mslp['longitudeOfFirstGridPointInDegrees']), \&#xA;                   float(grb_mslp['longitudeOfLastGridPointInDegrees']), int(grb_mslp['Ni']) )&#xA;&#xA;#Create evenly spaced lats using first to last grid point. int(grb[Nj]) = 721 (180/.25 + 1)&#xA;lats = np.linspace(float(grb['latitudeOfFirstGridPointInDegrees']), \&#xA;                   float(grb['latitudeOfLastGridPointInDegrees']), int(grb_mslp['Nj']) )&#xA;&#xA;#Grid shifting of lons. Not exactly sure how function works.&#xA;data, lons = shiftgrid(180., data, lons, start=False)&#xA;&#xA;grid_lon, grid_lat = np.meshgrid(lons, lats) #regularly spaced 2D grid. Still not sure how this works.&#xA;#---------------------------------------------------------------------------------------------&#xA;#Plotting MSLP on basemap&#xA;x,y = bmap(grid_lon,grid_lat) #Pass ERA5 lat/lon to basemap&#xA;cs = bmap.contour(x,y,data/100,10,colors='r') #Plot MSLP contours. Divide by 100 = mb&#xA;plt.clabel(cs,inline=1,inline_spacing=5,fontsize=10,fmt='%1.1f') #Add labels to contours&#xA;#---------------------------------------------------------------------------------------------&#xA;#Repeat process for other parameters until I figure out a better method&#xA;grb_uwind = grbs.select()[0] #U 10m wind component for 2012-03-26 @00UTC&#xA;grb_vwind = grbs.select()[1] #V 10m wind component for 2012-03-26 @00UTC&#xA;data_uwind = grb_uwind.values #U 10m wind values in m/s&#xA;data_vwind = grb_vwind.values #V 10m wind values in m/s&#xA;#---------------------------------------------------------------------------------------------&#xA;#Plotting wind on basemap&#xA;x,y = bmap(grid_lon,grid_lat) #Pass ERA5 lat/lon to basemap&#xA;barbs = plt.quiver(x,y,data_uwind,data_vwind) #Plot 10m wind in m/s&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The only solution I took a shot at was trying to plot every 50th data point using the notation:&lt;/p&gt;&#xA;&#xA;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;barbs = plt.quiver(x[::50],y[::50],data_uwind[::50],data_vwind[::50]) #Plot every 50th 10m wind point in m/s&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;However this produced a map with no almost no results. Would anyone have an idea of how I may be approaching this problem incorrectly? Would it be best to try and guess and check various values to plot instead of every 50 points? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I sincerely appreciate any recommendations on how to proceed forward. Thanks for taking the time to read this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Google Drive Link for Grib file: &lt;a href=&quot;https://drive.google.com/file/d/1XEuatdp5piyTIiADgZhxFHQ1_WghMwPJ/view?usp=sharing&quot; rel=&quot;noreferrer&quot;&gt;https://drive.google.com/file/d/1XEuatdp5piyTIiADgZhxFHQ1_WghMwPJ/view?usp=sharing&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18751" LastEditorDisplayName="user1066" LastEditDate="2020-01-18T04:10:40.920" LastActivityDate="2020-01-21T12:52:59.017" Title="Plotting ERA5 U/V Wind Data Using Python" Tags="|meteorology|wind|era|python|visualization|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19002" PostTypeId="1" AcceptedAnswerId="19004" CreationDate="2020-01-18T06:15:27.187" Score="3" ViewCount="459" Body="&lt;p&gt;I know several theories are proposed to explain Neanderthal extinction:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Consanguinity.&lt;/li&gt;&#xA;&lt;li&gt;Homo Sapiens competence.&lt;/li&gt;&#xA;&lt;li&gt;Climate change.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;But Finlayson et al (2008) quote the last ones lived south of the Iberian Peninsula. This make me think Europe's climate was too cold for them, so they migrated to South.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This surprises me as I have allways considered Neanderthal a cold specie adaptated to glaciar. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The oldest potential Neanderthal bones are dated to 430 kya (&lt;a href=&quot;https://en.wikipedia.org/wiki/Neanderthal&quot; rel=&quot;nofollow noreferrer&quot;&gt;Neanderthal, Wikipedia&lt;/a&gt;); they had faced to a previous glaciation and they survived.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zmQbn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zmQbn.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am not asking if the climate related extinction theory is the correct one. I am asking if there are evidences the climate on Europe was too cold for this specie. Also I would like to know if there are evidences they also migrated to South in the previous glaciar peak, around 150 kya ago.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Clive Finlayson, Darren A. Fa, Francisco Jiménez Espejo, Jóse S. Carrión, Geraldine Finlayson, Francisco Giles Pacheco, Joaquín Rodríguez Vidal, Chris Stringer, Francisca Martínez Ruiz (2008)&lt;/strong&gt;: &quot;&lt;em&gt;Gorham's Cave, Gibraltar—The persistence of a Neanderthal population&lt;/em&gt;&quot;. &lt;strong&gt;Quaternary International&lt;/strong&gt;, Volume 181, Issue 1, Pages 64-71, ISSN 1040-6182.&#xA;&lt;a href=&quot;https://doi.org/10.1016/j.quaint.2007.11.016&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/j.quaint.2007.11.016&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user18590" LastEditorDisplayName="user18590" LastEditDate="2020-01-18T08:13:02.423" LastActivityDate="2020-01-20T12:36:11.307" Title="Was the last glacier too hard for the Neanderthal?" Tags="|climate|paleontology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19003" PostTypeId="2" ParentId="18986" CreationDate="2020-01-18T06:16:14.590" Score="0" Body="&lt;p&gt;CO&lt;sub&gt;2&lt;/sub&gt; is dark in the long wave infrared wavelength so the higher the concentration the darker the atmosphere will be in this wavelength, and as you probably know darker colours absorb more heat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;CO&lt;sub&gt;2&lt;/sub&gt; is not a very powerful greenhouse gas but the amount of it in our atmosphere make this effect the dominating source for the heating we can see today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lots of other gases have a larger heating potential than CO&lt;sub&gt;2&lt;/sub&gt; but their concentration is low at the moment. The more complex a gas is the more heating potential it will have, this is due to the size of the individual gas molecules (CO&lt;sub&gt;2&lt;/sub&gt; has 3 atoms and methane has 5, so it will look darker in the long wave infrared band and therefore have a stronger heating potential).&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="2470" LastEditDate="2020-04-20T14:15:06.897" LastActivityDate="2020-04-20T14:15:06.897" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19004" PostTypeId="2" ParentId="19002" CreationDate="2020-01-18T10:16:24.170" Score="4" Body="&lt;p&gt;First things first, the reasons for the Neandertal(N) extinction are not known definitely. There is though no evidence of violence (*).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is an &lt;a href=&quot;https://www.nature.com/articles/nature13621&quot; rel=&quot;nofollow noreferrer&quot;&gt;overlap&lt;/a&gt; in Europe of N and anatomically modern humans (AMH) of several thousand years, even if N find sites are limited to the Mousterien industry alone. This is a conservative limit because N may have used &lt;a href=&quot;https://www.nature.com/articles/nature13621&quot; rel=&quot;nofollow noreferrer&quot;&gt;more advanced technology&lt;/a&gt; like blade production as well in their last millennia, which would extend N presence to ~32,000BP. Sites like Gorham's Cave fit into that picture, but this long chronology of N is &lt;a href=&quot;https://www.pnas.org/content/110/8/2781&quot; rel=&quot;nofollow noreferrer&quot;&gt;debated&lt;/a&gt; and &lt;a href=&quot;https://www.cell.com/heliyon/fulltext/S2405-8440(17)30864-2?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2405844017308642%3Fshowall%3Dtrue&quot; rel=&quot;nofollow noreferrer&quot;&gt;counterdebated&lt;/a&gt; :-)). Anyway, long before the last glacial maximum (~23 to 20ky BP) they were gone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Somewhat &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0047248410002198?via%3Dihub&quot; rel=&quot;nofollow noreferrer&quot;&gt;outdated&lt;/a&gt; is the view that N is a cold adaptation of the human lineage. The appearance of tools for clothing (bone needles) drastically rise with the Aurignacien, the first stone tool industry linked to AMH in Europe. That of course does not mean N didn't use clothes, but that they probably had not the same proficiency as Cro Magnon &amp;amp; consorts in making them. &lt;a href=&quot;https://www.pnas.org/content/115/37/9116&quot; rel=&quot;nofollow noreferrer&quot;&gt;Correlation&lt;/a&gt; of find sites and climate confirm the picture that N avoided cold climates. N populations were smaller than AMH, though &lt;a href=&quot;https://www.pnas.org/content/114/37/9859.full&quot; rel=&quot;nofollow noreferrer&quot;&gt;not really endangered by genetic bottlenecks&lt;/a&gt; (there is newer work concerning Denisovans, stating they never really split from N, but i can't find it).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By now it pretty clear that N and AMH &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4947341/&quot; rel=&quot;nofollow noreferrer&quot;&gt;interbred&lt;/a&gt; on &lt;a href=&quot;https://www.nature.com/articles/s41559-018-0735-8&quot; rel=&quot;nofollow noreferrer&quot;&gt;many occasions&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So why did they become extinct ? Together with other ice age megafauna in a highly stressed environment, loosing their way of subsistence ? Competition of top predators ? &lt;a href=&quot;https://www.nature.com/articles/s41598-019-38571-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Inbreading&lt;/a&gt; nevertheless ? Dwindling numbers and simple merge with AMH ? &lt;a href=&quot;https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0225117&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bad luck&lt;/a&gt; ? Unclear ...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(*) I want to add a remark here to the Shanidar 3 guy mentioned below. First of all, the authors do not exclude an accident. Second, the work has been criticized by Trinkaus et al. for methodological errors, as is cited &lt;a href=&quot;https://averyremoteperiodindeed.blogspot.com/2011/05/who-really-killed-shanidar-3.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. Similar arguments apply to &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC122968/&quot; rel=&quot;nofollow noreferrer&quot;&gt;St. Cesaire 1&lt;/a&gt; (healed skull fracture) is likely an accident, the argument for an intentional blow is too weak. I do not categorically exclude violence in the Paleolithic, the accusation is unfair, I only say there is no (undisputed) evidence. The &lt;a href=&quot;https://www.smithsonianmag.com/arts-culture/the-skeletons-of-shanidar-cave-7028477/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Shanidar burials&lt;/a&gt;, as well e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/La_Chapelle-aux-Saints_1&quot; rel=&quot;nofollow noreferrer&quot;&gt;La Chapelle aux Saints 1&lt;/a&gt; are seen as examples for compassion for those in need of care among N. Btw.: we haven't been at the meat of that yet, but i am not handing out fuel against my argumentation ;-)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It was stated that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Our ancestors killed the males of other tribes and raped the few remaining females. That our ancestors killed Neandertals who looked rather different is not a far stretch from killing other anatomically modern humans who looked only slightly different.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Both claims are not backed by science, &lt;a href=&quot;https://www.neanderthal.de/en/archaic-humans.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cro Magnon&lt;/a&gt; and &lt;a href=&quot;https://i.pinimg.com/originals/af/46/1b/af461ba463f0df60b43316019fa0dc08.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Neandertals&lt;/a&gt; were not that different (reconstructions Neandertal Museum, Mettmann, Germany) and normal people don't just attack others. Hunting strategies of late N and AMH in the early Aurignacien &lt;a href=&quot;https://www.nature.com/articles/s41598-019-50647-6&quot; rel=&quot;nofollow noreferrer&quot;&gt;don't differ&lt;/a&gt; by much.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That men were killed and woman stolen happened in very isolated cases in the Neolithic and contemporary Mesolithic, and violence also becomes evident in the Epipaleolithic/Neolithic precursors ~10kyBP , in sedentary or semi-sedentary groups, but that's not the point here. Rather not did it happen in the cold steppe of oxygen isotope stage 3 in Paleolithic Europe for obvious reasons: when the loss of a hunter could endanger the whole group; and women - having one child at a time to keep up the pace of mobility - moved around with the group. At the time 40kyBP population was low, it must rather be assumed that any accidental meeting was a cause of celebration and interchange, as is reflected in the genome.&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-20T12:36:11.307" LastActivityDate="2020-01-20T12:36:11.307" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19005" PostTypeId="2" ParentId="19002" CreationDate="2020-01-18T11:18:09.287" Score="1" Body="&lt;p&gt;You are quite right in assuming that Neanderthals were cold adapted, all authorities agree they were and probably to a greater extent than rival modern humans. There is no evidence that the climate during the ice age was too cold for Neanderthals, but that doesn't necessarily mean it had nothing to do with their demise. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The coming of the ice age meant that there was increased competition for scarce resources. For example, the best place for humans without modern housing to live in bitter weather is a cave. There are only a limited number of caves. Summers were shorter, and the fruits and vegetables of summer more limited, so modern man would have resented the increased competition from people who were very unlike themselves.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is a characteristic of modern humans that we tend to favour our own kind and to discriminate against people who differ from us. The white man's ill treatment of other races is a well known historical example of that. Modern humans, with their aggressive natures, would have forced the Neanderthals away from scarce resources and if necessary killed in order to do so. There is no evidence that the behavioural characteristics of Homo Sapiens Sapiens were any different during the last ice age than they are today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There was also some interbreeding, perhaps because there was a surplus of Neanderthal women after skirmishes between tribes (in modern times this seems to have been true in Australia, where during the 19th century male aborigines were often indiscriminately killed). The competition for resources in ice age Europe would have been more intense in the north, where resources were fewer, and this may well have, over many centuries, exerted pressure on Neanderthals to drift south.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-18T11:18:09.287" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19006" PostTypeId="1" AcceptedAnswerId="19176" CreationDate="2020-01-18T12:43:45.857" Score="3" ViewCount="286" Body="&lt;p&gt;I have a question about SWAN wave model, I tried to ask it at the SWAN mailing list, but with no luck, so I'm asking here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First of all I have to admit I'm not a professional SWAN user. All the knowledge of SWAN I have I have received from the user manual and google. Neither am I an oceanologist, so I can't say I really understand what the model does. However, I need to use it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I used GridBuilder to generate the grid, that is why I'm using curvilinear grids (the grid is actually a rectnagle, but GridBuilder generates only curvilinear grids when exporting for SWAN).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm trying to compute wave properties using this task:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;PROJECT 'p1' 'r1'&#xA;SET NAUTICAL&#xA;MODE DYN TWODimensional&#xA;PROP BSBT&#xA;&#xA;CGRID CURVILINEAR 90 86 EXC -9999 CIRCLE 10 0.03 0.55 40&#xA;READGRID COORDINATES 1 'data.grd' 4 0 0 FREE&#xA;INPGRID BOTTOM CURVILINEAR 0 0 90 86 EXC -9999&#xA;READINP BOTTOM 1 'data.bot' 4 0 FREE&#xA;&#xA;GEN2&#xA;WIND vel=20 dir=270&#xA;BLOCK 'COMPGRID' NOHEADER 'results.mat' LAY 3 XP YP BOTLEV WIND HSIG HSWELL VEL WATLEV DEPTH PER WLEN OUT 20200101.000000 5 MIN&#xA;&#xA;COMPUTE NONSTAT 20200101.000000 10 SEC 20200101.003000&#xA;STOP&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;If I understand the syntax correctly, then SWAN should compute wave propagation during 2.30 hours using wind with speed 20 m/s that blows from the West. However, when I check the results in MATLAB, I see that HSIG is about 0.0012 or something like that. This looks strange to me, since I'd expect waves to be much higher when the wind speed is 20 m/s which is a gale wind.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have computed the same properties for a whole day and the results are almost equal. These are the lines of the second task that differ from the first one:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;BLOCK 'COMPGRID' NOHEADER 'results.mat' LAY 3 XP YP BOTLEV WIND HSIG HSWELL WATLEV VEL DEPTH PER WLEN OUT 20200101.000000 30 MIN&#xA;&#xA;COMPUTE NONSTAT 20200101.000000 10 MIN 20200102.000000&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;However, period is about 2.0126634 and wave length is 5.0730591. This parameter combination looks strange to me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Did I miss something while composing the task? Thank you for help in advance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;data.grd:&#xA;&lt;a href=&quot;https://pastebin.com/RnsRssiY&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://pastebin.com/RnsRssiY&lt;/a&gt;&#xA;data.bot:&#xA;&lt;a href=&quot;https://pastebin.com/zbg4eySL&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://pastebin.com/zbg4eySL&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18753" LastActivityDate="2020-02-11T10:50:44.533" Title="SWAN wave model: HSIG is strangely low" Tags="|models|wind|waves|wave-modeling|ocean-models|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19008" PostTypeId="1" CreationDate="2020-01-18T14:30:00.107" Score="2" ViewCount="68" Body="&lt;p&gt;The image below shows their historical range (red) and current range (green) of hippopotamuses:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Yq4vq.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Yq4vq.gif&quot; alt=&quot;Africa, with the Nile river and sub-Sahara shown in red&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sub&gt;Image source: &lt;a href=&quot;https://isafari.nathab.com/blog/six-surprising-facts-about-hippos/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Six Surprising Facts About Hippos&lt;/a&gt;, 2014&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hence my question...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question&lt;/strong&gt;: Can hippopotamus fossils be found all along the Nile?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or at least perhaps they &lt;em&gt;used to be&lt;/em&gt; found all along the Nile, but now they're all excavated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NS7mc.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NS7mc.jpg&quot; alt=&quot;Hippopotamus.  Image source http://commons.wikimedia.org/wiki/File:Hippo_and_croco.jpg&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18754" LastActivityDate="2020-01-19T09:05:18.587" Title="Can hippopotamus fossils be found all along the Nile?" Tags="|fossils|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19009" PostTypeId="2" ParentId="19008" CreationDate="2020-01-18T17:07:47.000" Score="1" Body="&lt;p&gt;They most probably can, but there are two things to be borne in mind. The vast majority of animal corpses never fossilise, as fossilisation requires special conditions. This is especially true of animals from aquatic or very damp environments. Of those that do fossilise, only a tiny proportion are found and excavated.  Some weather out of the rock and crumble away on the surface without ever being noticed by an expert. Many hominid fossils have disappeared in this way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other thing required by hippos if they are to flourish and eventually fossilise is a source of vegetable food, sometimes from the river itself, but more usually from grazing on the nearby river bank. Much of the lower Nile today passes through cataracts and deserts, but six or seven thousand years ago the climate was moister, and much of the eastern Sahara was similar to East Africa today, and had similar animals and vegetation. It is quite feasible that in those days there was enough grazing on the banks of the lower Nile to support a population of hippos. They were certainly found in the Nile delta.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are short stretches that pass through cataracts or strong rapids. It is unlikely that these stretches were ever inhabited by hippos. The current is too strong and food sources difficult to reach, even if they were fairly nearby. Many hippopotamus carcasses are dismembered by crocodiles, which further reduces the likelihood that they will ever be found as fossils. Hippos don't like to stray more than a couple of hundred yards from water, and if there is plenty of aquatic vegetation they will seldom venture onto dry land.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2020-01-19T09:05:18.587" LastActivityDate="2020-01-19T09:05:18.587" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19010" PostTypeId="2" ParentId="18987" CreationDate="2020-01-18T18:05:28.637" Score="2" Body="&lt;p&gt;When I visit that link, the first option at the top (&quot;Data Product&quot;) defaults to &lt;code&gt;inst3_3d_asm_Np&lt;/code&gt;, which is atmospheric variables in pressure levels.  I suspect you need to change that dropdown option to &lt;code&gt;inst1_2d_asm_Nx&lt;/code&gt;, which is surface and near-surface variables.  The list is shows me for that option is,&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;DISPH = zero plane displacement height&#xA;PS = surface pressure&#xA;QV10M = 10-meter specific humidity&#xA;QV2M = 2-meter specific humidity&#xA;SLP = sea level pressure&#xA;T10M = 10-meter air temperature&#xA;T2M = 2-meter air temperature    &amp;lt;---- Here it is!&#xA;TO3 = total column ozone&#xA;TOX = total column odd oxygen&#xA;TQI = total precipitable ice water&#xA;TQL = total precipitable liquid water&#xA;TQV = total precipitable water vapor&#xA;TROPPB = tropopause pressure based on blended estimate&#xA;TROPPT = tropopause pressure based on thermal estimate&#xA;TROPPV = tropopause pressure based on epv estimate&#xA;TROPQ = tropopause specific humidity using blended tropp estimate&#xA;TROPT = tropopause temperature using blended tropp estimate&#xA;TS = surface skin temperature&#xA;U10M = 10-meter eastward wind&#xA;U2M = 2-meter eastward wind&#xA;U50M = eastward wind at 50 meters&#xA;V10M = 10-meter northward wind&#xA;V2M = 2-meter northward wind&#xA;V50M = northward wind at 50 meters&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="106" LastActivityDate="2020-01-18T18:05:28.637" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19011" PostTypeId="2" ParentId="18979" CreationDate="2020-01-18T20:08:01.690" Score="1" Body="&lt;p&gt;The podcast may have given the impression that sediment always gets buried or pushed down into the earth. This isnt the reality of the processes which are dynamic and dependent on geologic time as well as where these process can or can't happen. It really depends on the location and the processes happing there. &lt;/p&gt;&#xA;" OwnerUserId="12495" LastEditorUserId="12495" LastEditDate="2020-01-18T20:15:00.920" LastActivityDate="2020-01-18T20:15:00.920" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19012" PostTypeId="2" ParentId="18964" CreationDate="2020-01-18T20:09:35.593" Score="3" Body="&lt;p&gt;Climate Change definitely seem like a vicious cycle on a decadal scale. As other answers have pointed out there are numerous positive &lt;a href=&quot;https://climate.nasa.gov/nasa_science/science/&quot; rel=&quot;nofollow noreferrer&quot;&gt;feedbacks&lt;/a&gt; such as:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Warmer atmosphere holding more water vapor (which is a GHG) leading to more clouds&lt;/li&gt;&#xA;&lt;li&gt;Reduced snow cover reflecting less solar radiation (lower albedo)&lt;/li&gt;&#xA;&lt;li&gt;Reduced snow and ice cover on land leading to faster release of previously &amp;quot;locked up&amp;quot; methane in permafrost&lt;/li&gt;&#xA;&lt;li&gt;Warming increases decomposition of organic matter in general ( particularly worrying in previously waterlogged area e.g. peatland)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;However, this &amp;quot;vicious cycle&amp;quot; will likely decrease in strength over time, for reasons like blackbody radiation mentioned in the other answer. &amp;quot;Potential&amp;quot; full or partial reversal of the cycle, however, is dependant on biospheric feedbacks (blackbody radiation can only stabilize). Simply put, organisms collectively tend to stabilize environmental variables within certain ranges for homeostasis sake (humans are outliers, unfortunately), especially for bioresources like carbon dioxide and methane. I argue from an evolutionary standpoint, that &lt;strong&gt;most biospheric negative feedbacks&lt;/strong&gt; (which is in essence ecological responses refined through eons of large-scale nutrient imbalance selection experiment) &lt;strong&gt;operate on a larger timescale than the aforementioned positive feedbacks&lt;/strong&gt; because throughout Earth's history, it is unlikely that the Earth has experienced the current fast rate of warming that results in effective selection dynamics (you may argue we had seen that but massive and scarce pulse disaster is an example of ineffective selection that doesn't lead to meaningful adaptation and act more like lottery, whereas continuous and gradual impact is the best form of selection pressure). If there exists a biospheric &amp;quot;negative feedback&amp;quot; mechanism that leads to very fast cooling, in itself it would not be sustainable (just like fast warming) and would be weed out by evolution.&lt;/p&gt;&#xA;&lt;p&gt;So enough of evolutionary theory, how does an ecological negative feedback work (approximately)?&lt;/p&gt;&#xA;&lt;p&gt;Carbon dioxide fertilization and warming would favor and select the most efficient primary producers within the community repository (those who can use CO2 for growth and reproduction efficiently would be able to expand in numbers). Globally, in ocean, it would be r-strategists (phytoplanktons) that can grow and reproduce quickly whereas on land it would be trees that have conquered the limitation of height in primary production (I'm talking about in general what would be favored, there would be local variation no doubt). Also, note that two of the fastest flowing nutrient cycles i.e. C and N cycles are to some extent coupled and increased N deposition has indeed been shown to reinforce carbon sequestration (there is solid evidence of the increase in concentration of N compounds in the atmosphere which would deposit back to the environment when rained down.)&lt;/p&gt;&#xA;&lt;p&gt;It should be noted that while the primary producers have some time to enjoy the &amp;quot;feast&amp;quot;, the increased input of organic matter (OM) in the ecosystems (from primary producers) in turns constitute another selection pressure to select the most efficient consumers and decomposers. The duo processes would get closer and closer to an equilibrium eventually, but it is not likely to be the same state we had seen in pre-industrial time.&lt;/p&gt;&#xA;&lt;p&gt;So yes, in the &amp;quot;short-term&amp;quot; i.e. decades (which in itself is considered &amp;quot;long&amp;quot; relative to human lifespan), climate change does seem like a vicious cycle but on a longer-term it would likely find its &amp;quot;peace&amp;quot; through wax and wanes of biospheric responses.&lt;/p&gt;&#xA;" OwnerUserId="3241" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-01-19T13:53:15.720" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19013" PostTypeId="1" CreationDate="2020-01-18T21:42:41.140" Score="3" ViewCount="75" Body="&lt;p&gt;This question is a hypothetical, and has to do with the notion of cheap, modular turbines that can be sunk and anchored to a specific depth in a body of water. Each would not generate much power, but collectively that might be different, and it's a possible means of giving people living on riverfront properties greater self sufficiency. But that's not the question, just the context, so it need not be addressed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question is: When the topmost layer of a large body of moving water freezes, and assuming the water beneath is insulated by the ice and does not freeze, does that remaining water's rate of flow (rate, not volume) differ from its rate when none of the body of water was frozen?&lt;/p&gt;&#xA;" OwnerUserId="18757" LastActivityDate="2020-01-19T09:54:04.760" Title="If the top layer of a large river freezes, is the remainder's rate of flow affected?" Tags="|geophysics|hydrology|water|fluid-dynamics|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19014" PostTypeId="2" ParentId="19013" CreationDate="2020-01-19T09:54:04.760" Score="1" Body="&lt;p&gt;No, the rate of flow would usually be unaffected. The same volume of water has to get to the sea, so unless the ice was so thick and so well anchored to the riverbank as to exert pressure on the flow of water beneath, which is very unlikely, the rate of flow would remain the same. If, in the unlikely event that the ice exerted pressure on the water, the rate of flow would speed up. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's the same when you pinch the end of a garden hose. The same volume of water has to get through a narrower opening, so the jet becomes smaller but faster and more powerful because it is under pressure. For your purposes a faster flow would help your turbines to do their job but as I say, icing conditions are rarely such that ice would exert pressure on the flow. The friction between the current and the relatively thin coating of ice which usually occurs would not be enough to have any noticeable effect on the rate of flow. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-19T09:54:04.760" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19015" PostTypeId="2" ParentId="19001" CreationDate="2020-01-19T14:22:21.670" Score="11" Body="&lt;p&gt;First off very few people are using Basemap from Matplotlib these days. From this link &lt;a href=&quot;https://matplotlib.org/basemap/&quot; rel=&quot;nofollow noreferrer&quot;&gt;matplot basemap&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Basemap is deprecated in favor of the Cartopy project. See notes in Cartopy, New Management, and EoL Announcement for more details.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So we are going to use &lt;a href=&quot;https://scitools.org.uk/cartopy/docs/latest/&quot; rel=&quot;nofollow noreferrer&quot;&gt;cartopy&lt;/a&gt; in addition with matplotlib to plot the grib file that you have provided. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Before I actually show you the code that produces the plot it maybe useful to look at the data structures and their respective shapes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We basically are looking at four data structures i.e.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;latitudes, longitudes and u and v vectors.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;file = 'download.grib'&#xA;grbs = pygrib.open(file)&#xA;for g in grbs:&#xA;   lats, lons = g.latlons() # lats - latitude, lons - longitude&#xA;   lats, lons = np.array(lats), np.array(lons)&#xA;print(lats.shape)&#xA;print(lons.shape)&#xA;print(data_uwind.shape)&#xA;print(data_vwind.shape)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;So this prints as &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;(721,1440)&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;(721,1440)&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;(721,1440)&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;(721,1440)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As one can make out all the shapes are equal. Secondly I am generating the latitude and longitude arrays from the grib file. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When it comes to plotting with cartopy we need to choose a &lt;a href=&quot;https://scitools.org.uk/cartopy/docs/latest/tutorials/understanding_transform.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;projection&lt;/a&gt;. In my case I am choosing Plate Carree. You are welcome to choose another projection depending on your requirements. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So we will now look at the full code using pygrib and matplotlib and cartopy&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;import pygrib&#xA;import numpy as np&#xA;import matplotlib.pyplot as plt&#xA;import cartopy.crs as ccrs&#xA;from cartopy.mpl.ticker import LongitudeFormatter, LatitudeFormatter&#xA;import sys&#xA;&#xA;file = 'download.grib'&#xA;grbs = pygrib.open(file)&#xA;for g in grbs:&#xA;    lats, lons = g.latlons() # lats - latitude, lons - longitude&#xA;    lats, lons = np.array(lats), np.array(lons)&#xA;&#xA;grb_uwind = grbs.select()[0] #U 10m wind component for 2012-03-26 @00UTC&#xA;grb_vwind = grbs.select()[1] #V 10m wind component for 2012-03-26 @00UTC&#xA;data_uwind = grb_uwind.values #U 10m wind values in m/s&#xA;data_vwind = grb_vwind.values #V 10m wind values in m/s&#xA;&#xA;print(lons.shape)&#xA;print(lats.shape)&#xA;print(data_uwind.shape)&#xA;print(data_vwind.shape)&#xA;&#xA;ax1 = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))&#xA;&#xA;ax1.coastlines()&#xA;&#xA;ax1.stock_img()&#xA;&#xA;ax1.set_xticks([0, 60, 120, 180, 240, 300, 359.99], crs=ccrs.PlateCarree())&#xA;ax1.set_yticks([-90, -60, -30, 0, 30, 60, 90], crs=ccrs.PlateCarree())&#xA;lon_formatter = LongitudeFormatter(zero_direction_label=True,&#xA;                               number_format='.0f')&#xA;lat_formatter = LatitudeFormatter()&#xA;ax1.xaxis.set_major_formatter(lon_formatter)&#xA;ax1.yaxis.set_major_formatter(lat_formatter)&#xA;ax1.barbs(lons[::50,::50],lats[::50,::50],data_uwind[::50,::50],&#xA;  data_vwind[::50,::50],transform=ccrs.PlateCarree())&#xA;&#xA;plt.savefig('esse.png')&#xA;plt.show()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;and finally here is the plot. You can adjust the number of values you want to skip in the barbs function if you want a greater or lesser density by using the Python slicing syntax and skipping either lesser or greater number of elements.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ddsL8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ddsL8.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In response to the questions in the comments&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If one actually prints what is the type of &lt;strong&gt;g&lt;/strong&gt; in that for loop it turns out&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;for g in grbs:&#xA;    print(type(g))&#xA;    lats, lons = g.latlons() # lats - latitude, lons - longitude&#xA;    lats, lons = np.array(lats), np.array(lons)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;class 'pygrib.gribmessage'&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;class 'pygrib.gribmessage'&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;class 'pygrib.gribmessage'&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;class 'pygrib.gribmessage'&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;class  'pygrib.gribmessage'&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So it is of type &lt;a href=&quot;https://jswhit.github.io/pygrib/docs/pygrib.gribmessage-class.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;gribmessage&lt;/a&gt;. The fact it prints five times points to the fact that there are five GRIB Messages in that GRIB file. Each GRIB Message contains both data as well as metadata. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You could if you wish just exit the for loop after just one iteration since the same longitude/latitude is contained in each GRIB Message. &lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2020-01-21T12:52:59.017" LastActivityDate="2020-01-21T12:52:59.017" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19016" PostTypeId="1" CreationDate="2020-01-19T14:35:47.080" Score="1" ViewCount="55" Body="&lt;p&gt;I have an 2D hydrodynamic model in a approx. 10km² catchment and one rain event that goes one hour with measurements in a 5min interval. The reccurance interval for an event like that is close to 50years. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When I run my simulation software I get the flood heights for every m² in my catchment for every 30min. My question is, how do I validate my result? I guess, ideally I take the flood heights for 10 other rain events with the same intensity and duration and see if it fits my results. But I don't have these information. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;what could be approaches to validate my model?&lt;/p&gt;&#xA;" OwnerUserId="18169" LastActivityDate="2020-01-19T14:35:47.080" Title="how does model validation work? What is needed for an appropriate validation" Tags="|hydrology|models|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19017" PostTypeId="1" AcceptedAnswerId="19033" CreationDate="2020-01-19T14:36:05.743" Score="14" ViewCount="3992" Body="&lt;p&gt;My son wants to replicate some experiments and try to grow plants in Martian soil for his A-level science project.  I know NASA have managed to produce soil that mimics Martian soil, however I also know how expensive it is.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is, what is the closest proxy to real Martian soil that I can create using readily available supplies from builders merchants, garden suppliers, chemists, and supermarkets?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="18760" LastEditorUserId="6031" LastEditDate="2020-01-21T07:06:14.997" LastActivityDate="2020-01-21T07:06:14.997" Title="How to make Martian soil" Tags="|geology|soil|mars|soil-science|" AnswerCount="3" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="19018" PostTypeId="2" ParentId="19017" CreationDate="2020-01-19T16:23:36.080" Score="9" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Martian_regolith_simulant#MGS-1&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Martian_regolith_simulant#MGS-1&lt;/a&gt; has a link to a standard for Martian regolith that includes recipes. It will, though, not be trivial to replicate the grain size from the minerals. Silicate stuff is hard, one might need an expensive mill or grinder to produce it, or a friend who works at a stonecutter's workshop. Perchlorates are not included in the standard, yet, but maybe its healthier to leave that unimportant detail (slight sarkasm :-)) away.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mind potential health risks !&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Suggestion: maybe it would suffice for an A level project to visit a site where one could take away a basalt, grind it somewhere and sterilize it (heat it to &gt;100°C for an hour or so).&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-19T19:40:08.897" LastActivityDate="2020-01-19T19:40:08.897" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19019" PostTypeId="2" ParentId="19017" CreationDate="2020-01-19T17:56:07.563" Score="3" Body="&lt;p&gt;Just as there are many different rocks and soils on Earth, so there are many different rocks and soils on Mars. To reproduce a Martian soil, you need to bear two things in mind. Firstly it should have all the vital nutrients plants need to grow, and secondly it should have no component of biological origin. That rules out limestone for a start.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your soil should contain nitrogen, phosphorous, potassium, magnesium, sulphur and calcium. A volcanic tuff would be the best way to obtain these materials from a non-biological source; volcanic soils are known to be very fertile. If you can't find tuff, basalt and granite will do. Both are found in UK in areas where there were once volcanoes, such as Snowdonia in Wales and in Edinburg and other parts of Scotland. Granite will give a more acidic soil than basalt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Grind or pound your basalt into a fine powder. Do the same with your granite. If there are some wheat grain sized granules in your granite, it doesn't matter, natural soils have them too. You should prepare a number of pots with different proportions of the two main ingredients. A little silicon dioxide sand might be worth adding to some of your pots, there is plenty of it on Mars. Then sow your seeds and see what happens.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Different plants have different soil requirements, so you should try more than one species. The trickiest ingredient to obtain, and one of the most important, is nitrogen. several sources of nitrogen on Earth, for example lightning discharges and urine, are not available on Mars. I wonder if a sprinkling of potassium nitrate would count as cheating. It occurs as an evaporite on Earth, but I haven't heard that any has been found on Mars. See how well your plants can manage without it. Potassium nitrate (saltpetre) is available from chemists.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-19T17:56:07.563" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19020" PostTypeId="1" AcceptedAnswerId="19027" CreationDate="2020-01-19T20:28:02.390" Score="12" ViewCount="1647" Body="&lt;p&gt;I am sure there are different methodologies to arrive at such a number. Can someone &lt;strong&gt;in layman terms&lt;/strong&gt; describe some of the most widely used and trusted methods and what data are used? Sorry I am outside the field of climate modeling so the simpler the better.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can imagine a satellite observation-based model that calculates emissions on a spatial basis but I am not sure if our technology is advanced enough to do that accurately. However, this method would not allow segregation of GHG by source/sectors (electricity generation, cement production, agriculture etc.)&lt;/p&gt;&#xA;" OwnerUserId="18761" LastActivityDate="2020-01-23T22:26:06.737" Title="How is global greenhouse gas emission calculated?" Tags="|climate-change|climate-models|earth-observation|" AnswerCount="3" CommentCount="5" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19021" PostTypeId="2" ParentId="12601" CreationDate="2020-01-19T23:58:59.030" Score="3" Body="&lt;p&gt;The Rosgen river classification contains - besides slope, entrenchment and sinuosity - the width. But it is mostly applicable to natural rivers, not so much artificial waterways ...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://extension.umass.edu/riversmart/fgm-assessment-methods/rosgen-classification-natural-rivers-natural-channel-design&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://extension.umass.edu/riversmart/fgm-assessment-methods/rosgen-classification-natural-rivers-natural-channel-design&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Rosgen_Stream_Classification&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Rosgen_Stream_Classification&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://content.ces.ncsu.edu/application-of-the-rosgen-stream-classification-to-north-carolina&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://content.ces.ncsu.edu/application-of-the-rosgen-stream-classification-to-north-carolina&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_024290.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nrcs.usda.gov/Internet/FSE_DOCUMENTS/nrcs142p2_024290.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-20T12:28:56.473" LastActivityDate="2020-01-20T12:28:56.473" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19023" PostTypeId="1" CreationDate="2020-01-20T10:47:44.583" Score="3" ViewCount="70" Body="&lt;p&gt;Are there graphs with the median temperature development in the 20th century and if not, is there readily accessible data that can be used to calculate it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Median is statistically more stable, at the same time I'd be curious to plot the variance as well. My suspicion is the median rises less steep than the average but at the same time the variance (or for that matter min/max) changes significantly as well.&lt;/p&gt;&#xA;" OwnerUserId="18765" LastActivityDate="2020-01-20T10:47:44.583" Title="Median earth temperature development in 20th century" Tags="|climate-change|global-weirding|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="19024" PostTypeId="1" CreationDate="2020-01-20T13:00:21.837" Score="4" ViewCount="198" Body="&lt;p&gt;In the book &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/0415567750&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fundamentals of Geomorphology (Routledge Fundamentals of Physical Geography)&lt;/a&gt; by  Richard John Huggett there is a  sentence &quot; Intruded rocks, which must be mobile but not necessarily molten, may have a direct effect on landforms by causing doming of the surface.&quot; What is the difference between molten &amp;amp; mobile rock?&lt;/p&gt;&#xA;" OwnerUserId="18747" LastEditorDisplayName="user1066" LastEditDate="2020-01-21T13:07:06.673" LastActivityDate="2020-01-26T04:51:37.120" Title="What is the difference between mobile &amp; molten rock?" Tags="|geology|volcanology|petrology|igneous|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19025" PostTypeId="2" ParentId="19024" CreationDate="2020-01-20T13:16:38.823" Score="2" Body="&lt;p&gt;Molten rock must be a liquid, mobile rock is any rock capable of moving, sand and mud can be mobile. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2020-01-20T13:16:38.823" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19026" PostTypeId="2" ParentId="19020" CreationDate="2020-01-20T13:47:03.110" Score="9" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;I can imagine a satellite observation-based model that calculates&#xA;  emissions on a spatial basis but I am not sure if our technology is&#xA;  advanced enough to do that accurately.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It is. The first satellite designed to measure GHG is &lt;a href=&quot;http://www.gosat.nies.go.jp/en/&quot; rel=&quot;noreferrer&quot;&gt;GOSAT&lt;/a&gt;, from the Japanese space agency, launched in 2009 and still active today. It was followed by Nasa's &lt;a href=&quot;https://oco.jpl.nasa.gov/&quot; rel=&quot;noreferrer&quot;&gt;OCO-2&lt;/a&gt; in 2014. GOSAT measures CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; and CH&lt;span class=&quot;math-container&quot;&gt;$_4$&lt;/span&gt;, while OCO-2 measures only CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;. There is also an OCO-3, which has been sent to the ISS last year, but I'm not sure if it's already active.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, how does it work? Here is an image from the OCO-3 mission's website, labelled &quot;Artist interpretation of OCO-3 measurement&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HLRIZ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HLRIZ.jpg&quot; alt=&quot;Artist interpretation of OCO-3 measurement&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;OCO-2 mission's website explains the basic principle better than I could do, so I will just copy an excerpt here:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;To get the representative values of Xco&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;, or the amount of CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; in the measured space, the OCO-2 instrument will measure at a given location, the intensity of reflected sunlight off the Earth's surface at specific wavelengths. Gas molecules in the atmosphere absorb the sunlight at specific wavelengths. So when light passes through the Earth's atmosphere, the gases that are present leave a distinguishing fingerprint that can be captured. The OCO-2 spectrometers, working like cameras, will detect these molecular fingerprints. Then the absorption levels shown in these spectra, like a captured image, will tell us how many molecules were in the region where the instrument measured.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;There are also ground-based measurements, they are more precise but punctual, while satellite measurements have a global coverage. Ground-based measurements are actually used to calibrate the satellites. Also, ground-based measurements give concentrations at the surface, while satellite measurements give &quot;column-averaged concentrations&quot; through the atmosphere and are not able (yet) to do vertical profiles, i.e. to know at what altitude the gas contributing to the signal is located.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to dive more in-depth into this, there is a nice &quot;&lt;a href=&quot;https://seors.unfccc.int/applications/seors/attachments/get_attachment?code=IXWR56BUYS9UTUMFXH0ARXXJFETXU7MK&quot; rel=&quot;noreferrer&quot;&gt;Guidebook on the use of satellite greenhouse gases observation data&lt;/a&gt;...&quot; (Matsunaga &amp;amp; Maksyutov, 2018).&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-01-20T13:47:03.110" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19027" PostTypeId="2" ParentId="19020" CreationDate="2020-01-20T14:29:38.140" Score="10" Body="&lt;p&gt;Your question is simple enough, but the answer depends on what exactly you're looking for.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Who is emitting where right now?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Real-time global monitoring of greenhouse gas emissions with a high spatial resolution is an emerging technology.  We have very useful satellites (see Jean-Marie Privals answer), but they have limitations:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;All existing public satellites with instruments for high-resolution GHG measurements are in low Earth orbit, so they only see a particular place when they pass over, not all the time.  So far only the &lt;a href=&quot;https://www.wmo-sat.info/oscar/instruments/view/214&quot; rel=&quot;noreferrer&quot;&gt;Geostationary Interferometric Infrared Sounder (GIIRS)&lt;/a&gt; on the Chinese FengYung (FY)-4A satellite can in theory monitor CO₂ from a geostationary viewpoint, which allows for &quot;continuous&quot; monitoring (probably meaning hourly; it takes a while to scan the area of interest), but from what I've heard GIIRS is not performing very well.  Europe plans to launch the &lt;a href=&quot;https://www.wmo-sat.info/oscar/instruments/view/232&quot; rel=&quot;noreferrer&quot;&gt;Infra-Red Sounder (IRS)&lt;/a&gt; in 2023.  Either way, their spatial resolution will be much worse than for the low Earth orbit satellites, because geostationary orbit is so far away.&lt;/li&gt;&#xA;&lt;li&gt;They rely on visible radiation.  Although attempts to retrieve from infrared radiation exist, their information content is quite poor (for an Arctic methane example, see &lt;a href=&quot;https://www.atmos-meas-tech.net/9/1961/2016/&quot; rel=&quot;noreferrer&quot;&gt;Holl et al. (2016)&lt;/a&gt;).  In Jean-Marie Privals answer you can see an illustration of how reflected sunlight is used as a retrieval.&lt;/li&gt;&#xA;&lt;li&gt;They usually need clear skies.  We can't look below the clouds, but even retrieving above the cloud would require a very accurate characterisation of the cloud, and clouds are tricky.  So usually we just assume that the GHG concentration is the same with or without clouds, even when it probably isn't.&lt;/li&gt;&#xA;&lt;li&gt;Some private satellites exist with a very high spatial resolution, but I can't find much verifiable information about them.  &lt;a href=&quot;https://www.ghgsat.com/who-we-are/our-satellites/claire/&quot; rel=&quot;noreferrer&quot;&gt;GHGSat&lt;/a&gt; claims a spatial resolution of less than 50 metre.  Inevitably, that comes at the cost of field of view (12×12 km² claimed), it will only view a spot when actively pointing, so although it may be able to point anywhere on Earth, it will only view very specific areas and is in that sense not global.  It appears &lt;a href=&quot;https://www.bloomberg.com/news/articles/2019-04-17/new-wave-of-satellites-could-pinpoint-greenhouse-gas-offenders&quot; rel=&quot;noreferrer&quot;&gt;many similar commercial instruments are planned in the near future&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I can imagine a satellite observation-based model that calculates emissions on a spatial basis but I am not sure if our technology is advanced enough to do that accurately. However, this method would not allow segregation of GHG by source/sectors (electricity generation, cement production, agriculture etc.)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The spatial resolution of about 2 km may be good enough for that, unless the electricity plant is next to the cement producer, the emissions occur at night, the factory is switched off when the satellite happens to pass over, or it's cloudy (there are attempts to retrieve in the presence of clouds, but it's harder).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So while satellites are certainly very useful in GHG monitoring, it's difficult to get everything from satellites alone.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Where were emissions last month?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;We can average daytime GHG contentration measurements over the period of a month.  Combined with chemistry and circulation models, we can then try to estimate in what regions of the Earth those emissions may have occurred, but not with a precision high enough to tell &quot;electricity or cement&quot;.  This is an average of CO₂ measurements for July 2009:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://www.nasa.gov/images/content/403382main_portalBigPollution.jpg&quot; alt=&quot;July 2009 CO₂&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The limitations are less serious now: the satellite has multiple attempts to capture a particular scene, and will usually see at least one clear-sky overpass per month, probably multiple.  In the image above, there was probably also some form of data fusion to combine with other sources or fill gaps using neighbouring pixels.  The longer the time period we average over, the smoother the distribution will look.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;What were global emissions last year?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;However, if you are looking for &lt;em&gt;global&lt;/em&gt; emissions averaged over a long time period, we can make use of the observation that CO₂, and to a lesser degree CH₄, is a well-mixed gas.  Here, well-mixed means that it stays long enough in the atmosphere to reach pretty much everywhere given enough time.  That means that ultimately, it doesn't matter where you emit.  That's why &quot;global&quot; CO₂ concentrations may be measured at Mauna Kea (Hawaii, USA), even though this is far away from any emissions.  However, that also means that it doesn't tell us whether the CO₂ was emitted in India, Italy, or Idaho.  And much of the emitted CO₂ gets absorbed by the oceans, so the delta between this year and last is not enough to determine global emissions.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2020-01-20T15:25:51.463" LastActivityDate="2020-01-20T15:25:51.463" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19028" PostTypeId="1" AcceptedAnswerId="19037" CreationDate="2020-01-20T15:58:58.267" Score="4" ViewCount="1205" Body="&lt;p&gt;In Radar concept the SAR-Synthetic Aperture radar performs as side-looking to collect information, why it is not downlooking? There are down-looking radar also. So what are the differences between them&lt;/p&gt;&#xA;" OwnerUserId="15238" LastActivityDate="2020-01-21T09:21:01.880" Title="What are the differences between down-looking and side looking radar?" Tags="|remote-sensing|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19029" PostTypeId="2" ParentId="19028" CreationDate="2020-01-20T22:27:59.713" Score="2" Body="&lt;p&gt;Both down-looking and side looking radar look down. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Down-looking radar illuminates terrain forward and below the aircraft to detect targets on or near the ground. Stationary targets would be lost among the ground clutter, but moving targets on or near the ground can be separated by their doppler shift. Software eliminates the background clutter and leaves only small objects with a doppler shift displayed on the screen. These objects will be vehicles or low flying aircraft, which is what the fighter pilot is looking for.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Side-looking radar scans a wide swathe of land below and to one side of the aircraft, usually for mapping purposes, rather like  side-scan sonar maps the ocean floor.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="6031" LastEditDate="2020-01-21T01:15:42.200" LastActivityDate="2020-01-21T01:15:42.200" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19030" PostTypeId="1" CreationDate="2020-01-21T00:58:12.640" Score="14" ViewCount="4198" Body="&lt;p&gt;The BBC News item &lt;a href=&quot;https://www.bbc.com/news/science-environment-51180211&quot; rel=&quot;noreferrer&quot;&gt;Barometric pressure in London 'highest in 300 years' at least&lt;/a&gt; begins with&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Overnight, Sunday into Monday, London's Heathrow Airport recorded a barometric pressure of 1,049.6 millibars (mbar).&lt;/p&gt;&#xA;&lt;p&gt;It's very likely the highest pressure ever recorded in London, with records dating back to 1692.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It links to this &lt;a href=&quot;https://twitter.com/metoffice/status/1219028820977704961&quot; rel=&quot;noreferrer&quot;&gt;Met Office tweet&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;So far Mumbles Head in Wales appears to have recorded the highest pressure during this current settled spell, with 1050.5 hPa earlier this evening. This remains a little short of the 1050.9 hPa recorded at Benbecula 16.1.1957, and the UK record of 1053.6 hPa, Aberdeen 31.1.1902&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and then continues:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Met Office hourly observation reports recorded 1050.3 mbar at Liscombe in Devon, at 2100 GMT on Sunday evening. 1,050.2 mbar was recorded at Dunkeswell in Devon, and &lt;a href=&quot;https://www.bbc.co.uk/news/uk-wales-51174008&quot; rel=&quot;noreferrer&quot;&gt;1,050.5 mbar at Mumbles, in South Wales&lt;/a&gt;, shortly after.&lt;/p&gt;&#xA;&lt;p&gt;None of these measurements breach the &lt;strong&gt;1,053.6 mbar recorded at Aberdeen Observatory at 2200 GMT on 31 January 1902, which remains the national record&lt;/strong&gt;, but the events of the past 24 hours certainly marked the first time for over 60 years that 1,050 mbar has been attained anywhere in the British Isles, said Mr Burt.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;To discuss these records it is necessary to compare barometric pressure measurements to 0.1 mbar accuracy out of 1000 mbar, which is at the 100 parts-per-million level.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; How are barometric pressure measurements traceable over centuries to 100 parts per million &lt;em&gt;accuracy?&lt;/em&gt; What was the procedure used to calibrate barometric pressure centuries ago that could be reproduced and compared to today's standards, or is there a very old standard absolute barometer somewhere that is believed to have remained calibrated?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-01-23T14:20:32.430" Title="How are barometric pressure measurements traceable over centuries to 100 parts per million accuracy?" Tags="|measurements|barometric-pressure|instrumentation|" AnswerCount="5" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19031" PostTypeId="2" ParentId="19030" CreationDate="2020-01-21T02:04:52.380" Score="6" Body="&lt;p&gt;I don't think they are using that level of accuracy for the old readings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reporting pressure, in hPa, to one decimal place is being done for recent measurements. There are no values given for very old readings.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As for the record reading of 1053.6 hPa for 1902, I suspect that is a mathematical conversion of a reading that was most likely recorded in inches of mercury - the UK began converting to metric units in the 1970s.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to the reporting of atmospheric pressure to one decimal place, 0.1 hPa is 10 Pa, which is 1.02 kg/m&lt;sup&gt;2&lt;/sup&gt;, that seems a reasonable level of accuracy for modern barometers.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-01-21T02:04:52.380" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19032" PostTypeId="1" CreationDate="2020-01-19T15:34:19.327" Score="6" ViewCount="32" Body="&lt;p&gt;My son wants to replicate some experiments and try to grow plants in Martian soil for his A-level science project. I know NASA have managed to produce soil that mimics Martian soil, however I also know how expensive it is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is, what is the closest proxy to real Martian soil that I can create in the kitchen using readily available supplies from builders merchants, garden suppliers, chemists, and supermarkets?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="18760" OwnerDisplayName="Magic Bullet Dave" LastEditorUserId="6031" LastEditDate="2020-01-21T07:06:02.750" LastActivityDate="2020-01-21T07:06:02.750" Title="How to make Martian soil" Tags="|geology|soil|mars|soil-science|" AnswerCount="0" CommentCount="2" FavoriteCount="0" ClosedDate="2020-01-21T07:48:47.127" ContentLicense="CC BY-SA 4.0" />
  <row Id="19033" PostTypeId="2" ParentId="19017" CreationDate="2020-01-19T20:08:17.677" Score="9" Body="&lt;p&gt;the other posters are correct - true Martian soil contains perchlorates, high levels of iron, and can be highly toxic. What you want to look for is called &quot;Mars Regolith Stimulant&quot;. There are a few websites that have recipes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://reprage.com/post/home-made-simulant-mars-dirt&quot; rel=&quot;noreferrer&quot;&gt;https://reprage.com/post/home-made-simulant-mars-dirt&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The five most abundant ingredients, account for almost 90% of the dirt taken from Mars samples.&lt;/p&gt;&#xA;  &#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;SiO2 - 49.5%&lt;/li&gt;&#xA;  &lt;li&gt;Fe2O3 - 17.9%&lt;/li&gt;&#xA;  &lt;li&gt;Al2O3 - 7.2%&lt;/li&gt;&#xA;  &lt;li&gt;MgO - 7.7%&lt;/li&gt;&#xA;  &lt;li&gt;CaO - 6.7%&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;  &#xA;  &lt;p&gt;That seems like a good starting point. If I pad those out to reach 100% and use the results as a weight ratio, it should make a decent first batch of home-made Martian soil. Luckily most of this stuff can be found in hardware and health food stores.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;SiO2&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Silicon dioxide, yeah sand. You can go budget and get a bag of propagation sand (it won’t be 100% silica). If you want a bit more precision you can hunt around for educational or scientific samples that contain less impurities. You can get 2.7 kilograms for about \$16&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Fe2O3&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Iron oxide, is red cement colouring and is often advertised as red oxide or similar. You can get 2.2 kilograms for about \$20&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Al2O3&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Aluminium oxide, is used as an abrasive. It gets stuck to sandpaper and is used in sandblasting. It was a bit difficult obtaining smaller amounts in Australia (places wanted to sell me 20kg bags). You can get 340 grams for about \$10.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;MgO&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Magnesium oxide, is a dietary supplement found in health food stores. You can get 225 grams for about \$10.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;CaO&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Calcium oxide, Now this one is tricky. I couldn’t easily buy calcium oxide. It seems that calcium oxide reacts with CO2 in the air and gets converted into calcium carbonate. But you can buy calcium carbonate (CaCO3) as a dietary supplement. This can then be turned into calcium oxide by ‘lime-burning’, just heat it up in a kiln to above 825°C. You can get 340 grams of calcium carbonate for about \$10&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and others that lets you buy your own (I won't link to them because of advertising, but the Martian garden is one such site). I think you could get close with the above recipe. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In any scenario, I would strongly recommend supervising your child when they are working with the stimulant. It should be handled with gloves and a respirator mask. Ingestion is very dangerous, and it might not be the worst idea to check the number of your local poison control center. While this may seem like overkill, it would make a great section of your child's science project. &quot;Methodology&quot;, &quot;Safety&quot;, and &quot;Standards &amp;amp; Practices&quot; are all very important parts of working in a lab and in engineering. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Best of luck!&lt;/p&gt;&#xA;" OwnerDisplayName="mothman" LastActivityDate="2020-01-20T02:42:31.940" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19034" PostTypeId="2" ParentId="19030" CreationDate="2020-01-21T03:33:29.777" Score="9" Body="&lt;p&gt;A &lt;a href=&quot;https://en.wikipedia.org/wiki/Barometer#Mercury_barometers&quot; rel=&quot;noreferrer&quot;&gt;mercury barometer&lt;/a&gt; is a simple, easy-to-build barometer that turns the problem of calibrating a pressure standard into one of calibrating a length standard.  Accuracy of length standards has long been a concern of merchants and those regulating them; in 1692, the standard would probably have been a brass prototype yard in the possession of the Royal Society.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Historically, atmospheric pressure in the UK was measured in &quot;inches of mercury&quot;; a pressure of 0.1 millibars is about 0.003 inches of mercury (roughly 1/256th of an inch).  I haven't been able to find evidence of rulers of that accuracy in 1692, but ones divided to the 64th of an inch (0.5 millibars) certainly were available.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short, 100 parts per million?  Probably not.  500 parts per million?  Certainly.&lt;/p&gt;&#xA;" OwnerUserId="2643" LastActivityDate="2020-01-21T03:33:29.777" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19035" PostTypeId="1" CreationDate="2020-01-21T03:52:19.287" Score="13" ViewCount="2805" Body="&lt;p&gt;According to the Phys.org article &lt;a href=&quot;https://phys.org/news/2020-01-ozone-depleting-substances-late-20th-century-arctic.html&quot; rel=&quot;noreferrer&quot;&gt;&quot;Ozone-depleting substances caused half of late 20th-century Arctic warming, says study&quot;&lt;/a&gt; (emphasis added):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A study published today in &lt;em&gt;Nature Climate Change&lt;/em&gt; by researchers at Columbia University examines the greenhouse warming effects of ozone-depleting substances and finds that &lt;strong&gt;they caused about a third of all global warming from 1955 to 2005, and half of Arctic warming and sea ice loss during that period.&lt;/strong&gt; They thus acted as a strong supplement to carbon dioxide, the most pervasive greenhouse gas; their effects have since started to fade, as they are no longer produced and slowly dissolve.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Questions:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Do these &quot;ozone-depleting substances&quot; also have infrared-absorbing greenhouse impact unrelated to their ozone-depleting chemistry, or is the story more complex?&lt;/li&gt;&#xA;&lt;li&gt;Why the different fractions; 1/3 of all global warming but 1/2 of arctic sea ice loss?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="7741" LastEditDate="2020-01-21T15:05:16.677" LastActivityDate="2020-01-21T23:53:02.840" Title="Why have &quot;ozone-depleting substances&quot; led to a third of all global warming and half of arctic sea ice loss?" Tags="|atmosphere|climate-change|atmospheric-chemistry|sea-ice|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19036" PostTypeId="2" ParentId="19035" CreationDate="2020-01-21T08:29:59.153" Score="11" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Global_warming_potential&quot; rel=&quot;noreferrer&quot;&gt;Global warming potential&lt;/a&gt; (GWP) describes how much global warming a particular gas may induce in a particular time period.  It is often expressed in terms of CO₂-equivalent.  The best known greenhouse gases are carbon dioxide (CO₂), methane (CH₄), and water vapour (H₂O).  Water vapour is short lived and therefore its emission is not a primary climate change contributor (but it is a strong secondary contributor through the water vapour feedback).  However, there are other greenhouse gases that are, per unit volume, extremely strong.  Some of those are CFCs and HFCs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wikipedia quotes various IPCC reports and summarises the 20-year global warming potential of some greenhouse gases (emphasis mine):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;CO₂: 1 (by definition)&lt;/li&gt;&#xA;&lt;li&gt;Methane: 86&lt;/li&gt;&#xA;&lt;li&gt;Nitrous oxide (N₂O): 268&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;HFC-134a: 3790&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;CFC-11: 7020&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The GWP is a result of a combination of the strength of radiative forcing and atmospheric lifetime.  The radiative forcing is about 20,000 times stronger, due to those complicated molecules having lots of rotational and vibrational states that can absorb IR radiation.  Fortunately, their lifetime is also shorter, resulting in an estimated GWP of around 7000-11000 for commonly used CFCs.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to answer your first question: &lt;strong&gt;yes&lt;/strong&gt;, ozone-depleting CFCs have a very strong greenhouse gas potential independent of their ozone-depleting properties.  Their replacement, HCFCs, are much more gentle to ozone but still very strong greenhouse gases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not sure why their effect is relatively stronger in the Arctic.  The &lt;a href=&quot;https://www.nature.com/articles/s41558-019-0677-4&quot; rel=&quot;noreferrer&quot;&gt;research article you linked&lt;/a&gt; provides some ideas:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It is also legitimate to ask whether such a large contribution of ODS to Arctic warming might be an artefact of the CAM5LE model.&lt;br&gt;&#xA;  (...)&lt;br&gt;&#xA;  In addition to a larger RF, two factors produce an enhanced Arctic warming with increasing ODS in CAM5LE: (1) a stronger lapse rate feedback (which is positive for the Arctic, confirming previous work) and (2) a weaker negative net cloud feedback (with contributions from both long and short waves).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Note that the article seems to entirely ignore that &lt;strong&gt;H&lt;/strong&gt;FCs are not phased out at all — HFCs have largely replaces CFCs because they don't destroy ozone, but still have a strong GWP.  I find that a rather serious omission because it strongly undermines their conclusion that &lt;em&gt;the phase-out of ODS, which is well under way, will substantially mitigate Arctic warming&lt;/em&gt; (the article groups HFCs together with CFCs, which makes sense for GWP but not for ozone depletion).&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2020-01-21T10:12:30.987" LastActivityDate="2020-01-21T10:12:30.987" CommentCount="15" ContentLicense="CC BY-SA 4.0" />
  <row Id="19037" PostTypeId="2" ParentId="19028" CreationDate="2020-01-21T09:21:01.880" Score="4" Body="&lt;p&gt;A radar measures the time of arrival of the backscattered signal to infer the distance between the target and the platform (satellite, aircraft, whatever). If two targets are at the same distance from the platform, one on the left and one on the right because the platform is looking down, then their signals will arrive at the same time, making them impossible to distinguish. Looking sideways removes this ambiguity. Look at this figure from the &lt;a href=&quot;http://www.csr.utexas.edu/rs/sensors/whatissar/rar.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Center for Space Research&lt;/a&gt; of the University of Texas (there is also a text explanation in the link).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/43yTz.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/43yTz.gif&quot; alt=&quot;down looking versus side looking&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-01-21T09:21:01.880" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19038" PostTypeId="1" CreationDate="2020-01-21T11:11:36.690" Score="4" ViewCount="97" Body="&lt;p&gt;Elastic waves in the earth are described by the elastodynamic equations&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{align}&#xA;    \rho \frac{\partial^2 u}{\partial t^2} &amp;amp;= (2 \mu + \lambda) \frac{\partial^2 u}{\partial x^2} + \mu \left( \frac{\partial^2 u}{\partial y^2} +  \frac{\partial^2 u}{\partial z^2} \right) + (\lambda+\mu) \left( \frac{\partial^2 v}{\partial x \partial y} + \frac{\partial^2 w}{\partial x \partial z} \right) \\&#xA;    \rho \frac{\partial^2 v}{\partial t^2} &amp;amp;= (2 \mu + \lambda) \frac{\partial^2 v}{\partial y^2} + \mu \left( \frac{\partial^2 v}{\partial x^2} +  \frac{\partial^2 v}{\partial z^2} \right) + (\lambda+\mu) \left( \frac{\partial^2 u}{\partial x \partial y} + \frac{\partial^2 w}{\partial y \partial z} \right) \\&#xA;    \rho \frac{\partial^2 w}{\partial t^2} &amp;amp;= (2 \mu + \lambda) \frac{\partial^2 w}{\partial z^2} + \mu \left( \frac{\partial^2 w}{\partial x^2} +  \frac{\partial^2 w}{\partial y^2} \right) + (\lambda+\mu) \left( \frac{\partial^2 u}{\partial x \partial z} + \frac{\partial^2 v}{\partial y \partial z} \right) &#xA;\end{align}&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it possible to have a very thin and stiff layer in a surrounding soft material? If yes, is it possible to approximate the thin layer by a thin film with free boundaries and a uniform displacement over the thickness direction (&lt;span class=&quot;math-container&quot;&gt;$\partial / \partial z = 0$&lt;/span&gt;)? In this case, the equations of motion become&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{align}&#xA;    \rho \frac{\partial^2 u}{\partial t^2} &amp;amp;= (2 \mu + \lambda) \frac{\partial^2 u}{\partial x^2} + \mu \frac{\partial^2 u}{\partial y^2} + (\lambda+\mu) \frac{\partial^2 v}{\partial x \partial y}  \\&#xA;    \rho \frac{\partial^2 v}{\partial t^2} &amp;amp;= (2 \mu + \lambda) \frac{\partial^2 v}{\partial y^2} + \mu \frac{\partial^2 v}{\partial x^2} + (\lambda+\mu)\frac{\partial^2 u}{\partial x \partial y}  \\&#xA;    \rho \frac{\partial^2 w}{\partial t^2} &amp;amp;= \mu \left( \frac{\partial^2 w}{\partial x^2} +  \frac{\partial^2 w}{\partial y^2} \right) &#xA;\end{align}&lt;/span&gt;&#xA;Do these equations describe a realistic case? Does this state have a specific name (like plane stress or antiplane shear ...)? &lt;/p&gt;&#xA;" OwnerUserId="18769" LastActivityDate="2020-03-09T05:09:39.887" Title="Waves in very thin layer" Tags="|geology|geophysics|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19039" PostTypeId="1" AcceptedAnswerId="19049" CreationDate="2020-01-21T12:52:33.897" Score="1" ViewCount="182" Body="&lt;p&gt;I am writing a mineral guide for smartphones which classifies minerals according to their formation environment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Tf21J.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Tf21J.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;https://earthscience.stackexchange.com/questions/18167/is-this-classification-of-mineral-formation-environments-correct&quot;&gt;sugestions on this related question&lt;/a&gt;, I changed the classification to:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Sedimentary&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Magmatic&lt;/strong&gt; &lt;s&gt;&lt;strong&gt;Tardimagmatic&lt;/strong&gt;&lt;/s&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Metamorphic&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Hydrothermal&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Supergenic??&lt;/strong&gt; &lt;s&gt;&lt;strong&gt;Exogenous&lt;/strong&gt;&lt;/s&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The question mark is because comments on &lt;a href=&quot;https://earthscience.stackexchange.com/questions/18560/confused-about-the-genetic-term-supergene-mineral&quot;&gt;other related question&lt;/a&gt; sugest &lt;em&gt;supergenic&lt;/em&gt; would not be a good term to include weathering resulting minerals from igneous, sedimentary or metamorphic bodies on surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would it be appropiated to classify weathering minerals as &lt;em&gt;Superficial alteration&lt;/em&gt;. The first time I wrote the DB I refered it as &lt;em&gt;Exogenous&lt;/em&gt;, but it looks no correct acording to answers on first linked question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just &lt;em&gt;Weathering&lt;/em&gt; maybe? That would be acceptable on the US? &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;h1&gt;Edit&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;From @&lt;a href=&quot;https://earthscience.stackexchange.com/a/19049/18590&quot;&gt;Fred answer&lt;/a&gt; and @&lt;a href=&quot;https://earthscience.stackexchange.com/a/18181/18590&quot;&gt;Gimelist previous answer&lt;/a&gt;, I will finally classify them as:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Sedimentary&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Magmatic&lt;/strong&gt; &lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Metamorphic&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Hydrothermal&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Supergenic&lt;/strong&gt; &lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Weathered&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Thanks. I hoppe this is the best for my future users/students. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will post a link to this on a page &quot;about the classification&quot;, encouraging the students to join the site and ask their questions.&lt;/p&gt;&#xA;" OwnerDisplayName="user18590" LastEditorDisplayName="user18590" LastEditDate="2020-01-22T19:49:37.887" LastActivityDate="2020-01-22T19:49:37.887" Title="How to genetically classify a mineral resulted from weathering?" Tags="|geology|mineralogy|minerals|weathering|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19040" PostTypeId="2" ParentId="19039" CreationDate="2020-01-21T13:54:28.703" Score="1" Body="&lt;p&gt;I don't see anything wrong with Supergenic. It is widely understood and includes weathering. I would stick to Supergenic if I were you. You probably realise that there are some rocks which, as they are produced in more than one way, would fit into several of your classification headings. There is no way of avoiding this. Quartz, for example, can be magmatic, metamorphic, sedimentary or hydrothermal.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-21T13:54:28.703" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19041" PostTypeId="2" ParentId="19030" CreationDate="2020-01-21T16:19:43.203" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;How are barometric pressure measurements traceable over centuries to 100 parts per million &lt;em&gt;accuracy&lt;/em&gt;?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;To compare &lt;em&gt;records&lt;/em&gt; of barometric temperature, this standard &lt;strong&gt;&lt;em&gt;doesn't&lt;/em&gt;&lt;/strong&gt; necessarily have to be met.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recording barometric pressure to 100 parts per million &lt;em&gt;precision&lt;/em&gt; has been possible for centuries because it's reasonably trivial to observe movement of the level in a hydrostatic barometer by small fractions of an inch with the help of simple instrumentation. Over short timescales, the small differences between different readings are important meteorologically and for a single, stable barometer these changes are likely to remain &lt;em&gt;accurate&lt;/em&gt; too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Guaranteeing that the barometric pressure is &lt;em&gt;accurate&lt;/em&gt; in &lt;em&gt;absolute terms&lt;/em&gt; (and therefore that the various recording instruments that have doubtlessly been used over the centuries can be treated interchangeably) is harder, although the physics, &lt;a href=&quot;https://earthscience.stackexchange.com/a/19034/13508&quot;&gt;as Mark has detailed&lt;/a&gt;, is simple enough to give meteorologists a good shot at it. It's plausible enough that it would be foolish to &lt;em&gt;reduce&lt;/em&gt; the accuracy by adding the rounding error of recording the pressure at a lower precision. Yet when we talk about a record like this being surpassed, the premium on the &lt;em&gt;difference&lt;/em&gt; between these records taken centuries apart being &lt;em&gt;accurate&lt;/em&gt; is not that high.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The fact that one record surpassed another serves primarily a &lt;em&gt;symbolic&lt;/em&gt; milestone that helps laypeople grasp roughly what kind of exceptional conditions are being described. Reports of the record don't &lt;em&gt;have&lt;/em&gt; to make assertions about accurate comparisons between atmospheric conditions centuries apart at all (and as far as I can see they haven't). They have to choose a record that serves as a representative comparison, but so long as they limit their remarks to the difference between the &lt;em&gt;records&lt;/em&gt; they are completely correct. Officials &lt;em&gt;did&lt;/em&gt; record values to at least a 0.1 mbar of precision today, and some of values &lt;em&gt;were&lt;/em&gt; higher than any that had been recorded by officials before.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are, after all, merely records of barometric pressures at select points over the area of a whole country. They serve as an indicator of the barometric pressures governing the weather systems governing the country's weather as a whole at the time. There have doubtless been other very high pressure systems in the intervening years, and equally it's very likely that this has been one of the highest (on account of it breaking records where pressure has been recorded) but we don't &lt;em&gt;really&lt;/em&gt; have to be absolutely certain that it has been the highest ever by any particular measure.&lt;/p&gt;&#xA;" OwnerUserId="13508" LastEditorUserId="13508" LastEditDate="2020-01-21T17:18:16.773" LastActivityDate="2020-01-21T17:18:16.773" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19043" PostTypeId="2" ParentId="19030" CreationDate="2020-01-21T16:58:57.197" Score="17" Body="&lt;p&gt;Mark's answer about mercury barometers is correct - but it is not the complete story.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Barometer&quot; rel=&quot;noreferrer&quot;&gt;Barometers&lt;/a&gt; were initially constructed using water, not mercury, on the manometer principle.  Water is lighter than mercury, so a water barometer requires a 10.3m tube.  1mbar is therefore roughly 1cm, and 0.1mbar measurement is clearly trivial using a ruler with 1mm gradations.  Of course the exact units of measurement would depend on the country in which the measurements were taken, but it should be clear that measurement to this precision was perfectly possible, albeit with an inconveniently-large barometer!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mercury barometers, with around 75cm height of mercury at 1bar, were significantly more convenient.  As Mark says, this does require a much more accurate ruler to measure it though.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the accuracy of a simple ruler is not the complete story either.  The &lt;a href=&quot;https://en.wikipedia.org/wiki/Vernier_scale&quot; rel=&quot;noreferrer&quot;&gt;Vernier scale&lt;/a&gt; was invented (or at least popularised) around the same time.  With a floating Vernier marker, mercury barometers could be read accurately to around 1/10th of the ruler scale.  For a ruler marked in 1mm intervals, a 75cm column of mercury could therefore be read to 133ppm accuracy, which is close enough in accuracy to the original water-based barometers.&lt;/p&gt;&#xA;" OwnerUserId="14995" LastActivityDate="2020-01-21T16:58:57.197" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19044" PostTypeId="1" CreationDate="2020-01-21T17:24:23.560" Score="5" ViewCount="147" Body="&lt;p&gt;Since, given enough compaction, salt is able to behave like a fluid &amp;amp; buoyant too if it's overlain by a higher density rock (it could be fine grained clay or a sandy sequence). But in another case, when a layered sandstone is inter bedded with shale, &amp;amp; given enough pressure and temperature, the shale becomes mobile &amp;amp; flows while the sandstone shows brittle properties. Do the above two situations work on different principles or same, or are these two completely different processes?&lt;/p&gt;&#xA;" OwnerUserId="18747" LastEditorUserId="2470" LastEditDate="2020-01-23T12:13:46.603" LastActivityDate="2022-11-14T11:07:10.807" Title="Can we separate a sandy, clayey &amp; salt layer on basis of their rheological properties?" Tags="|geology|sedimentology|petrology|structural-geology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19045" PostTypeId="2" ParentId="19035" CreationDate="2020-01-21T18:38:16.850" Score="0" Body="&lt;p&gt;The linked article seems poorly written. It refers to unexplained climate models and doesn't link the actual paper. &#xA;In any case the most intuitive assumption is that the missing ozone doesn't reflect the sun UV rays, in this case it would be the opposite of the greenhouse effect, increasing the incoming of radiation instead of stopping the outgoing radiation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;BTW take care, the article says that the contribution is given to the Arctic warming, not to the global warming. In that region the UV rays come at such an angle that they are much weaker. But I guess that the contribution is so high because the Arctic is so cold that a small increase may have a greater impact.&lt;/p&gt;&#xA;" OwnerUserId="18774" LastActivityDate="2020-01-21T18:38:16.850" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19046" PostTypeId="1" CreationDate="2020-01-21T23:22:31.037" Score="5" ViewCount="566" Body="&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/19043/6031&quot;&gt;This answer&lt;/a&gt; to &lt;em&gt;How are barometric pressure measurements traceable over centuries to 100 parts per million accuracy?&lt;/em&gt; describes a floating mercury barometer, and mentions that some employed a Vernier scale for additional precision.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since mercury is so dense (about 13.5 g/cm&lt;sup&gt;3&lt;/sup&gt;) that many metals will float in it, but I'm having a hard time imagining how to make a barometer using his principle, and how a scale (Vernier or otherwise) is used to read the height of an object floating in mercury in order to determine barometric pressure.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="2470" LastEditDate="2020-01-22T02:56:46.267" LastActivityDate="2021-07-27T09:18:42.707" Title="What does a floating mercury barometer look like? How does it work and how is buoyancy used?" Tags="|measurements|barometric-pressure|instrumentation|history-of-science|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19047" PostTypeId="2" ParentId="19035" CreationDate="2020-01-21T23:34:25.830" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Do these &quot;ozone-depleting substances&quot; also have infrared-absorbing greenhouse impact unrelated to their ozone-depleting chemistry, or is the story more complex?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Yes, the paper (I have access) actually said that the warming is because of the strong direct radiative forcing of the ozone-depleting agent rather than because of their ability to destroy ozone. They conclude this from findings of running a full (according to historical data) vs. fixed ozone-depletant + stratospheric ozone level (at 1955) vs. fixed ozone-depletant only ensemble simulations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The paper specifically gives two examples:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Chlorofluorocarbons &lt;strong&gt;CFC-11 and CFC-12&lt;/strong&gt; are 19,000- and 23,000-fold more radiatively efficient, respectively, than CO2 (in terms of Wm^–2 per parts per&#xA;billion), resulting in 20-year &lt;strong&gt;global warming potentials&lt;/strong&gt; &lt;strong&gt;7,000- and&#xA;11,000-fold larger&lt;/strong&gt;. So yes, these gases are crazy considering how much we put them into the atmosphere during 1955 - 2005&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Why the different fractions; 1/3 of all global warming but 1/2 of arctic sea ice loss?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;First thing is you have to know this is just what the model (based on its mechanistic representation) tells you about the relative contributions. The paper tried to explain that ozone-depletant has a higher &quot;warming efficacy&quot; (than CO2, CH4 &amp;amp; N2O) meaning that &lt;strong&gt;for the same amount of radiative forcing, it can produce larger temperature differences&lt;/strong&gt;. So, this discrepancy results from the divergence of radiative forcing and actual temperature impact at a certain location. In particular, the paper said &lt;strong&gt;ozone-depletant reinforces the lapse-rate positive feedback and attenuates the negative net cloud feedback&lt;/strong&gt; in the Arctic. As to how it actually works (and why it doesn't work for CO2, CH4, N2O), I am not an expert in this regard so you would have to look at it yourself. I am guessing this has to do with their molecular weight affecting their movement in the atmosphere (height where they are found relative to the vertical temperature profile and height of clouds at a particular location).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(PS. I also have a feeling that part of it may be just an artifact from parameterization to match Arctic Amplification, meaning that it is more &quot;sensible&quot; to adjust large warming potential gas by a small percentage than to adjust a low warming potential gas by a large percentage. But don't take it too seriously, I am not an expert in this regard.)&lt;/p&gt;&#xA;" OwnerUserId="3241" LastEditorUserId="3241" LastEditDate="2020-01-21T23:53:02.840" LastActivityDate="2020-01-21T23:53:02.840" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19049" PostTypeId="2" ParentId="19039" CreationDate="2020-01-22T05:08:33.820" Score="2" Body="&lt;p&gt;My understanding of &lt;a href=&quot;https://en.wikipedia.org/wiki/Supergene_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;supergene&lt;/a&gt; is that it is about mineral enrichment/concentration at the base of an oxidized zone, within a weathered profile. The seasonal/periodic rise and fall of the local water table is critical to supergene &lt;em&gt;enrichment&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The descending meteoric waters oxidize the primary (hypogene) sulfide ore minerals and redistribute the metallic ore elements. Supergene enrichment occurs at the base of the oxidized portion of an ore deposit.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Supergene would not apply to the top of a weathered zone but to the base.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My old geology dictionary (&lt;em&gt;The Penguin Dictionary of Geology&lt;/em&gt;, 1979) describes supergene as:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A word suggesting an origin literally 'from above'. It is used almost&#xA;  exclusively for processes involving water, with or without dissolved&#xA;  material, percolating down from the surface. Typical supergene&#xA;  processes are solution, hydration, oxidation, deposition from&#xA;  solution, reactions of ions in solution with ions in existing minerals.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;To me, supergene has a specific meaning, it may be part of the weathering process in some locations, but weathering involves the breaking down of rocks due to: reactions with atmospheric gasses, water (usually rain), changes brought on by plants, bacteria wind and temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My suggestion to use the term weathering or weathered.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-01-22T05:08:33.820" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19050" PostTypeId="1" AcceptedAnswerId="19051" CreationDate="2020-01-22T05:12:43.323" Score="7" ViewCount="1352" Body="&lt;p&gt;I've been searching for a 2017 or 2018 or 2019 (or any combo) gridded dataset for surface temperature for the globe with a 0.1 degree resolution. Unfortunately even after hours of searching, for this time range, I've only been able to find ones with at most 0.5 degree resolution. Does anyone have any recommendations of where I might be able to find this kind of data?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If gloabal temperature isn't available, I'm specifically searching for Africa, South Asia, and South America (or any combo of those) - so if anyone knows where this data is available, it would be much appreciated!&lt;/p&gt;&#xA;" OwnerUserId="14670" LastActivityDate="2021-10-05T07:16:49.317" Title="Is there a recent global gridded temperature dataset with 0.1 deg resolution?" Tags="|temperature|database|weatherdata|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19051" PostTypeId="2" ParentId="19050" CreationDate="2020-01-22T09:53:45.480" Score="15" Body="&lt;p&gt;The most important reanalysis datasets covering until present time (I'm excluding the others that stop some years before present time) currently available are:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.ecmwf.int/en/forecasts/datasets/reanalysis-datasets/era5&quot; rel=&quot;nofollow noreferrer&quot;&gt;ERA5&lt;/a&gt; by &lt;a href=&quot;https://www.ecmwf.int/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ECWMF&lt;/a&gt;: 1979-present (soon 1950-present), temporal resolution of 1 hour and spatial resolution quarter degree (0.25 x 0.25);&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.cru.uea.ac.uk/data&quot; rel=&quot;nofollow noreferrer&quot;&gt;CRU&lt;/a&gt; by the &lt;a href=&quot;http://www.uea.ac.uk/&quot; rel=&quot;nofollow noreferrer&quot;&gt;UEA&lt;/a&gt;: 1900-present (some variables 1850-present), temporal resolution 3 or 6h, spatial resolution half degree (0.5 x 0.5);&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://disc.gsfc.nasa.gov/datasets?keywords=GLDAS&quot; rel=&quot;nofollow noreferrer&quot;&gt;GLDAS&lt;/a&gt; by &lt;a href=&quot;https://ldas.gsfc.nasa.gov/gldas&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA&lt;/a&gt;: 1948-present, temporal resolution 3 or 6h, spatial resolution quarter degree (0.25 x 0.25).&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-era5-land?tab=overview&quot; rel=&quot;nofollow noreferrer&quot;&gt;ERA5-LAND&lt;/a&gt; by ECMWF: 1981-present, temporal resolution of 1 hour and spatial resolution 0.1°x0.1°, global coverage, but only land-covered surface.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;(please, feel free to edit the answer to add more)&lt;/p&gt;&#xA;&lt;p&gt;You could download one of those and process these temperature data using a simple resampling procedure bringing it at the resolution you are interested in by using &lt;a href=&quot;https://code.mpimet.mpg.de/projects/cdo/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CDO&lt;/a&gt; or another similar software. The procedure could be based on a bilinear interpolation of the original data with a finer grid. This would bring uncertainty because the correct procedure would be to use the reanalysis as boundary conditions in a regional climate model, but it would give a good approximation of the data you are looking for.&lt;/p&gt;&#xA;&lt;p&gt;The only dataset I am aware of that is providing global data at a resolution of a 0.1 deg. resolution is the &lt;a href=&quot;http://www.gloh2o.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;MSWEP&lt;/a&gt; by JRC and Princeton, but present data are not available for free, and it includes only precipitation data.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;2021 EDIT: newly released data&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://chelsa-climate.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CHELSA&lt;/a&gt; by &lt;a href=&quot;https://www.wsl.ch/en/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;WSL&lt;/a&gt;: 1979-near present, temporal resolution day, spatial resolution 30 arcsec (~1km);&lt;/p&gt;&#xA;" OwnerUserId="8087" LastEditorUserId="8087" LastEditDate="2021-10-05T07:16:49.317" LastActivityDate="2021-10-05T07:16:49.317" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19052" PostTypeId="1" CreationDate="2020-01-22T14:21:55.370" Score="1" ViewCount="231" Body="&lt;p&gt;The 2.25 billion-year-old Yarrabubba crater in Western Australia has recently been identified as the world's oldest impact crater. It is said to be 43 miles (69 km) in diameter, yet the photo which accompanies the news item shows a circular structure about 430 metres across, hardly more than quarter of a mile. I realise there has been massive erosion since the crater was formed, but erosion to this extent is hard to believe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Manicouagan crater in Quebec has a clearly visible diameter of 62 miles (100 km). which is its official diameter. Its age is 214 million years. Erosion to the same extent as is claimed for the Yarrabbuba crater would give Manicouagan an original diameter of about 10,000 miles (16,000 km)! Clearly this is impossible, so being only about a tenth the age of the Australian example it has eroded far less. But that is not the same as no erosion at all.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone give an approximate diameter of Manicouagan at the time it was formed?  Another peculiarity of the Yarrabbuba crater is that in the photo it appears to be slightly domed rather than sunken. Is this an artefact of the photograph, a sort of optical illusion, or is it really raised?&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="6" LastEditDate="2020-01-22T15:28:09.933" LastActivityDate="2020-01-24T06:06:15.690" Title="Original Diameter of Ancient Impact Craters" Tags="|earth-history|erosion|asteroids|impact-craters|" AnswerCount="2" CommentCount="8" ClosedDate="2020-01-31T10:17:34.807" ContentLicense="CC BY-SA 4.0" />
  <row Id="19053" PostTypeId="2" ParentId="19052" CreationDate="2020-01-22T14:48:43.943" Score="4" Body="&lt;p&gt;There is a recent &lt;a href=&quot;https://www.nature.com/articles/s41467-019-13985-7&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt;(open access) that i assume the news item refers to. That paper does not  mention 430m. They use a magnetic anomaly to extrapolate the original crater size from the eroded central uplift. The crater itself is long since eroded.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Therefore, the ~20 km diameter magnetic anomaly has been interpreted to represent the remnant of the deeply buried central uplift of the structure, which is consistent with an original crater diameter of 70 km&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The present day exposure represents a deep erosional level, as neither impact breccias nor topographic expressions of the over-turned rim or central uplift are preserved.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The samples for age determination were taken from a structure called &quot;Barlangi rock&quot;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The structure is centred on a large exposure of granophyre known locally as Barlangi Rock (Fig. 1; 118˚50′E, 27˚10′S). Barlangi granophyre is a sodic rhyolite[...] that has been interpreted as an impact-generated melt rock[...], radiating dyke-like apophyses of granophyre outcrop as far as 3 km from the centre of the structure&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is not the central uplift itself like from a crustal rebound, but&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... has thus been interpreted to have intruded into the Yarrabubba monzogranite along faults rather than forming a flat-lying, crater-filling melt sheet ...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The filling at Barlangi has a complex age range (2.79 to 2.23Gy). 2.229 has been determined out of this as the most likely date of the impact. And of course, since then it has been exposed to weathering and erosion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So there are two separate things here: the size inferred from magnetism, and the age determination from an intrusive melt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wikipedia estimates the &lt;a href=&quot;https://en.wikipedia.org/wiki/Manicouagan_Reservoir#Impact_crater&quot; rel=&quot;nofollow noreferrer&quot;&gt;Manicouagan&lt;/a&gt; structure's original diameter to ~100km. More on that event and it's proposed impact on the environment can be found &lt;a href=&quot;https://www.nature.com/articles/srep29609&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; (open access). The introduction names an initial diameter of 90km for Manicouagan.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope that clarifies. Corrections and annotations welcome.&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-22T18:46:00.117" LastActivityDate="2020-01-22T18:46:00.117" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19054" PostTypeId="1" CreationDate="2020-01-23T09:04:10.640" Score="1" ViewCount="57" Body="&lt;p&gt;I would like to create a district/province-level air quality data for all the countries in South Asia from 2010 onward using satellite data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As someone with absolutely zero background in remote-sensing, could anyone please suggest (relevant papers, websites, anything really) how do I go on about this?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;" OwnerUserId="18786" LastEditorUserId="18081" LastEditDate="2020-01-23T09:31:58.980" LastActivityDate="2020-01-23T09:31:58.980" Title="District/province wise air quality data for South Asia (2010 onward)" Tags="|remote-sensing|air-pollution|air-quality|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19055" PostTypeId="2" ParentId="17863" CreationDate="2020-01-23T10:10:58.963" Score="5" Body="&lt;p&gt;Short answer: &lt;strong&gt;yes, there are other mountains which contains oceanic crust in their lithologies&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The process you described as &quot;the upthrust of ocean crust&quot; is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Obduction&quot; rel=&quot;nofollow noreferrer&quot;&gt;obduction&lt;/a&gt;. The resulting rock sequence is called an &lt;a href=&quot;https://en.wikipedia.org/wiki/Ophiolite&quot; rel=&quot;nofollow noreferrer&quot;&gt;ophiolite&lt;/a&gt;. As you can see &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_ophiolites&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, there is quite a lot of them around the world! One of the most studied is the Oman ophiolite. I have seen the Chenaillet ophiolite in the French Alps, it's quite spectacular.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that ophiolites usually include not only basalts (often in form of pillow lavas, typical of emplacement under the ocean), but also other oceanic crust lithologies such as gabbros, and even the underlying lithospheric mantle, often as serpentinite (a peridotite altered by water).&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Edit:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found a  &lt;a href=&quot;https://archive.usgs.gov/archive/sites/geomaps.wr.usgs.gov/parks/olym/content.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Guide to the Geology of Olympic National Park&lt;/a&gt; on the USGS website. Unfortunately some links are dead, but you can still find lots of information on the range's lithology and formation. The page on &lt;a href=&quot;https://archive.usgs.gov/archive/sites/geomaps.wr.usgs.gov/parks/olym/olym5.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;basalt and its associated rocks&quot;&lt;/a&gt; mentions the presence of gabbro (a magmatic rock with the same composition as basalt but a crystalline texture due to slower cooling), but not that of any mantle rock. According to this other page on &lt;a href=&quot;https://archive.usgs.gov/archive/sites/geomaps.wr.usgs.gov/parks/olym/olym14.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;colliding plates and Olympic rocks&quot;&lt;/a&gt;, the basalt is not from the oceanic crust itself but rather from a submarine volcano emplaced avove the plate (fig. 26). So, &lt;strong&gt;the Olympic Mountains would not be an ophiolite per se, but rather an accretionary wedge&lt;/strong&gt;, i.e. &quot;a thick wedge of rocks produced by the progressive offscraping of ocean floor sediments during subduction and their accretion to the continental margin&quot; (excerpt from the guide's preface).&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2020-01-27T12:07:11.530" LastActivityDate="2020-01-27T12:07:11.530" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19057" PostTypeId="2" ParentId="19030" CreationDate="2020-01-23T12:25:35.920" Score="1" Body="&lt;p&gt;The maximum reading was taken at Aberdeen Observatory and &lt;a href=&quot;https://homepages.abdn.ac.uk/npmuseum/BSHS%20Display/Meteorology/slides/ABDNP201635a03.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;they still have a barometer&lt;/a&gt; which was in use during the period the reading was taken (the inscriptions dates it to 1888 and after 1922 it was still in use).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's not a mercury one - mercury is relevant as the article states records go back to 1692, before aneroid barometers were invented, though does not state that records before 1902 were that accurate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The dial appears to be marked with a resolution of 0.01 inches Hg, or ~0.34 mbar, though it's a little hard to say whether it's that or half that from the photo. It also has more than one scale and a digit window so the range is more than one revolution of the dial, a bit like modern dial indicators which measure down to one micron.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't think this will be the instrument that was used - this looks like a portable one but I'd imagine they had a charting ones for the observatory, and it was twenty years out of date by then - but it does set a lower bound on the accuracy of instruments known to be available to the observatory where the reading was made in 1902. The description for the charting barometer in their historic collection doesn't specify dates, and I couldn't read its plaque from the photo.&lt;/p&gt;&#xA;" OwnerUserId="1337" LastEditorUserId="18081" LastEditDate="2020-01-23T14:20:32.430" LastActivityDate="2020-01-23T14:20:32.430" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19058" PostTypeId="1" CreationDate="2020-01-23T13:53:14.310" Score="3" ViewCount="136" Body="&lt;p&gt;I'm working to design the atmosphere of a fictional planet inspired by Venus (let's call it Cael).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Cael's atmosphere at an altitude of 50 km&lt;/strong&gt; is essentially identical to &lt;strong&gt;Earth's atmosphere at sea level&lt;/strong&gt;, and parallels Earth's atmosphere as altitude increases beyond that. I want to figure out what needs to happen in the lower 50 kilometers in order to keep the Earth-like atmosphere where it is. My problem is that I can't find resources on what happens when an Earth-like atmosphere is extended &lt;em&gt;downward&lt;/em&gt; by any significant distance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The atmospheres of &lt;strong&gt;Venus&lt;/strong&gt;, &lt;strong&gt;Jupiter&lt;/strong&gt;, and &lt;strong&gt;Saturn&lt;/strong&gt; all contain distinct layers of varying composition caused by the changes in temperature and pressure with increasing depth. While none of them have a layer of Earth-like composition to use as a convenient reference, it seems logical that this would hold also hold true in the case of Cael. So my question is,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What kind of layers would form beneath a complete Earth-like atmosphere?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the purposes of this question, the Earth-like atmosphere starts at the imaginary surface where the temperature and pressure of Cael's atmosphere are functionally identical to Earth's atmosphere at sea level, 50 km above the true rocky surface. I'll call this the Sea-Level Equivalent altitude, or SLE.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just like on Earth, Cael has a tropopause roughly 10-20 km above the SLE that marks the beginning of the stratosphere. Above that is the mesosphere, thermosphere, and exosphere. As on Earth, atmospheric composition is effectively constant all the way up to the lowest part of the thermosphere due to turbulent mixing dominating its molecular interactions.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A very rough estimate for the air pressure at Cael's surface is 50 atm, according to &lt;a href=&quot;https://www.mide.com/air-pressure-at-altitude-calculator&quot; rel=&quot;nofollow noreferrer&quot;&gt;this &quot;Air Pressure at Altitude Calculator&quot; from Mide Technology Corp.&lt;/a&gt; That pressure is well above the critical pressure for nitrogen (33.5 atm) and right around the critical pressure for oxygen (49.8).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even if we assume that temperature remains constant rather than increase as you descend beneath the Earth-temperature SLE, the critical temperatures of both gasses are below -100°C, a temperature that has never been recorded at Earth's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, I would expect to find a very high volume of supercritical nitrogen as well as a bit of supercritical oxygen at Cael's rocky surface. Argon, neon, and methane would all be supercritical under those conditions as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also expect liquid water oceans, because Cael needs to have enough water to experience water clouds and precipitation above the SLE, and my guesstimates for temperature and pressure are within the liquid section of water's phase diagram.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More information about Cael:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Mass: 6 × 10²⁴ kg&lt;/li&gt;&#xA;&lt;li&gt;Average radius of planet surface: 6,450 km&lt;/li&gt;&#xA;&lt;li&gt;Average gravity at planet surface: 9.65 m/s²&lt;/li&gt;&#xA;&lt;li&gt;Average altitude of SLE: 50 km&lt;/li&gt;&#xA;&lt;li&gt;Average gravity at SLE: 9.5  m/s²&lt;/li&gt;&#xA;&lt;li&gt;Average air pressure at SLE: 1 atm&lt;/li&gt;&#xA;&lt;li&gt;Solar intensity and spectral makeup at SLE is the same as on Earth&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="18790" LastEditorUserId="18790" LastEditDate="2020-01-24T13:39:43.553" LastActivityDate="2020-01-24T13:39:43.553" Title="How does composition change if you extend an Earthlike atmosphere 50km below sea level?" Tags="|atmosphere|models|atmosphere-modelling|" AnswerCount="1" CommentCount="4" ClosedDate="2020-01-26T16:46:31.903" ContentLicense="CC BY-SA 4.0" />
  <row Id="19059" PostTypeId="2" ParentId="19058" CreationDate="2020-01-23T14:41:53.047" Score="0" Body="&lt;p&gt;This seems like a World Building question. I presume that on your imaginary planet something, perhaps an asteroid strike, has created a huge bowl 50 km deep. On the rim of the bowl, the atmospheric pressure and composition are the same as at sea level on Earth. You want to know what conditions would be like at the bottom.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In some respects a bit like Venus. Very hot, but exactly how hot would depend on whereabouts on the planet this deep bowl had formed. The composition of the atmosphere would be the same as at sea level (I assume the lip of the bowl is not close to a sea). The pressure at the bottom would be many atmospheres, but not as many as the 90 atmospheres on Venus. It would seldom rain down there because of the heat and high pressure. Rain falling in from high altitude would usually evaporate before reaching the bottom. As explorers ascended the sides, conditions would become more normal &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would it be habitable? Yes, but how habitable depends on where on the planet this bowl occurred. There would be habitats on the slopes, where conditions were less extreme than at the bottom. If this bowl or basin were in the tropics, the bottom would probably be too hot to sustain life. A water supply would also be problematic. Pressure is less of a problem; there are life forms 12 km down or deeper in Earth's ocean trenches.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-23T14:41:53.047" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="19060" PostTypeId="2" ParentId="19020" CreationDate="2020-01-23T22:17:21.887" Score="3" Body="&lt;p&gt;Satellite data is relatively new and is likely to be used to compare and refine calculations of emissions by other means rather than used as the principle means for estimating emissions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consumption based accounting is the main way we get the declared emissions, including methane, nitrous oxides and carbon monoxide and others as well as CO2, for the world or individual nations under internationally agreed UNFCCC guidelines. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Consumption based emissions are calculated from how much fossil fuels of each type are used and what their emissions factors are - how much fuel of each type, what kind of use for each type and how much emissions for that use. Similarly industrial emissions and products as well as land uses and estimates of how much emissions or take up of CO2 by the different uses is all calculated.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="18145" LastEditDate="2020-01-23T22:26:06.737" LastActivityDate="2020-01-23T22:26:06.737" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19061" PostTypeId="1" CreationDate="2020-01-24T01:50:52.640" Score="3" ViewCount="44" Body="&lt;p&gt;Is there the risk of an &quot;Issaquah firestorm&quot;, something with the intensity of Tyee Creek or Thirtymile but hitting suburban areas of the Cascade foothills like Issaquah, Samammish, Cougar Mountain?&lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2020-01-24T01:50:52.640" Title="How susceptible is the greater Seattle area to an wildland-urban interface conflagration like the Camp Fire or 1991 Oakland firestorm?" Tags="|forest|natural-disasters|wildfire|fire|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19062" PostTypeId="1" AcceptedAnswerId="19200" CreationDate="2020-01-24T05:17:27.473" Score="5" ViewCount="509" Body="&lt;p&gt;&lt;strong&gt;Help Requested&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone know if &lt;a href=&quot;https://gmao.gsfc.nasa.gov/reanalysis/MERRA-2/&quot; rel=&quot;nofollow noreferrer&quot;&gt;MERRA2&lt;/a&gt; contains hourly Global Horizontal Irradiance (GHI) data, or some other measurement which we can use to calculate GHI?, If so, could you please let me know how?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Background&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am attempting to use &lt;a href=&quot;https://pvlib-python.readthedocs.io/en/stable/&quot; rel=&quot;nofollow noreferrer&quot;&gt;PVLib library&lt;/a&gt; in python to calculate the estimated solar generation of various solar farms across the world. PVLib can estimate GHI, Direct Normal Irradiance (DNI) and Diffuse Horizontal Irradiance (DHI), but I was hoping to bring in actual data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Research and own findings&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've used MERRA-2 data previously to source hourly temperature and wind speeds. So I went looking here first for GHI data. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I looked though &lt;a href=&quot;https://disc.gsfc.nasa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;GES DISC directory&lt;/a&gt; for various MERRA2 reanalysis files. I found M2T1NXRAD (found &lt;a href=&quot;https://disc.gsfc.nasa.gov/datasets/M2T1NXRAD_5.12.4/summary?keywords=%22MERRA-2%22&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;) and figured since it contains radiation data that it would contain GHI, but I didn't see anything which looked like GHI in the field list (found &lt;a href=&quot;https://gmao.gsfc.nasa.gov/pubs/docs/Bosilovich785.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;). I did find &quot;surface incident shortwave flux (SWGDN)&quot;, but I am not a meteorologist and don't know how this relates to GHI, or if it can even be converted to GHI?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Browsing the internet, it does look like there is some relation between SWGDN and GHI. I've seen many publications allude to it (such as &lt;a href=&quot;https://www.researchgate.net/figure/and-Figure-3-confirm-that-MERRA-2-primarily-overestimates-annual-GHI-on-the-order-of-4_fig3_329642180&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;https://www.researchgate.net/publication/331392320_Evaluation_of_Solar_Radiation_from_MERRA_MERRA-2_ERA-Interim_and_CFSR_Reanalysis_Datasets_Against_Surface_Observations_for_Multan_Pakistan&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;) but I wasn't able to figure out how they are calculating it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;an extract from the above article states&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;MERRA-2 uses the Goddard Earth Observing System version 5&#xA;  (GEOS-5) atmospheric model and data assimilation system (DAS). The&#xA;  dataset offers two-dimensional diagnostics of surface fluxes, single&#xA;  level meteorology, vertical integrals and land states, generated at 1&#xA;  hourly, 3 hourly, daily and monthly intervals. This paper utilises the&#xA;  surface incident shortwave flux (SWGDN) from the single-level&#xA;  diagnostic tavgM_2d_rad_Nx data product averaged over a monthly&#xA;  interval (NASA 2017). &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;But it doesn't say how to convert SWGDN to GHI? if anyone knows how these two measures relate to one another, I would love an explanation!&lt;/p&gt;&#xA;" OwnerUserId="18376" LastEditorUserId="8087" LastEditDate="2020-01-24T09:26:08.817" LastActivityDate="2020-02-13T23:54:35.823" Title="How to get GHI data from MERRA-2?" Tags="|meteorology|weather-forecasting|nasa|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19063" PostTypeId="2" ParentId="19052" CreationDate="2020-01-24T06:06:15.690" Score="3" Body="&lt;p&gt;When comparing the sizes of the two craters, you are confusing how erosion works.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Erosion did not &lt;em&gt;shrink&lt;/em&gt; the original crater to from 43 miles to 430 meters. The crater was 43 miles across and was completely erased: Nothing of it remains, neither the rim nor the central uplift. In fact, erosion has even erased the rocks into which the crater was blasted. This is what erosion over 2 billion years does. The only thing that is left are remnants &lt;em&gt;under&lt;/em&gt; the central uplift, and these are 430 meters across.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, the Manicouagan is as large as it has always been. Erosion has simply not leveled its outer ring yet. But when it does, it will still have the same diameter. Erosion isn't going to &lt;em&gt;shrink&lt;/em&gt; it, it's just going to level it.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2020-01-24T06:06:15.690" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19064" PostTypeId="1" CreationDate="2020-01-24T09:50:16.643" Score="9" ViewCount="2242" Body="&lt;p&gt;According to Wikipedia's article &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Earth&quot; rel=&quot;noreferrer&quot;&gt;Atmosphere of Earth&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Outgassing from volcanism, supplemented by gases produced during the late heavy bombardment of Earth by huge asteroids, produced [Earth's second] atmosphere, consisting largely of nitrogen plus carbon dioxide and inert gases.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;However, it doesn't explain any further than that. Where exactly did the nitrogen come from? Was it already gaseous or was it in the form of compounds that broke down releasing N&lt;sub&gt;2&lt;/sub&gt; gas?&lt;/p&gt;&#xA;" OwnerUserId="5417" LastActivityDate="2020-02-03T11:43:51.920" Title="Where did the atmosphere's nitrogen come from?" Tags="|atmosphere|earth-history|nitrogen|" AnswerCount="1" CommentCount="5" ClosedDate="2020-02-10T08:56:06.717" ContentLicense="CC BY-SA 4.0" />
  <row Id="19065" PostTypeId="2" ParentId="19064" CreationDate="2020-01-24T11:28:29.633" Score="-6" Body="&lt;p&gt;There was some free nitrogen in the secondary atmosphere, and also some ammonia (NH3). Ammonia is present today in the atmospheres of Jupiter, Saturn and other gas giants in the outer solar system. The main constituent of the Earth's primeval atmosphere was carbon dioxide, which also makes up the bulk of the atmospheres of Venus and Mars. The ammonia eventually decomposed into nitrogen and hydrogen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When we look at the atmospheres of Mars and Venus, we see that they contain only 3 percent nitrogen, while our atmosphere contains 78 percent. The main reason for this is that Mars and Venus still retain most of their primeval CO2, while Earth's has largely disappeared because of biological processes (coal,limestone etc). The atmosphere of Titan also contains a massive percentage of nitrogen because competing gases, apart from methane, have mostly disappeared, frozen out by the intense cold&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We also need to consider outgassing from volcanoes. These emissions consist mainly of CO2 and water vapour, but there are small amounts of nitrogen and ammonia, and other gases as well. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-24T11:28:29.633" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19067" PostTypeId="2" ParentId="9103" CreationDate="2020-01-24T23:45:13.533" Score="-1" Body="&lt;p&gt;&quot;But anthropogenic climate change is real and demonstrable, and doesn't need cartoonists to make pretty graphics that get shared all over the internet to encourage belief in it.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But that is not the point in debate. That is the 97% (or even 100%) view. No-one disputes it. The subject of debate is, broadly, five factors: how much has the Earth warmed since the 1940s? How different is that from natural variability? How much of it is man-made through heat-trapping gases released by human activity (a subtly different matter)? How much warming is likely in the future? How much of a hazard will that future warming be?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;None of these things are constrained very well at all. Only if all of them align as the most alarmist &quot;scientists&quot; say is there any reason at all to change our way of living in response to climate fears, and evidence suggests that is not the case. Even the IPCC suggests the effect will be measured as 0.2-2% reduction in world GDP by 2080, at a time when world GDP will be at least 300% of that we have today - so dropping that to &quot;only&quot; 194-199.4% rise from now to then.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sound evidence suggests that one factor, poor siting of thermometers and temperature sensors, has exaggerated the temperature rise in the USA by up to 100%. The USA has one of the best systems of temperature measurement in the world. In many parts of the world the original data have been manipulated multiple times, almost always reducing old temperatures and increasing more recent ones; in Australia, for example, some analysis has suggested this is responsible for all the recorded warming. In Bolivia (I think it is) there is not a single thermometer in the system used for reporting world temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So even the first part, the temperature rise, is not known to within a factor of 2.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Heck, there are problems even before that: multiple measurements in the 19th century, before regular measurements were made, showed CO2 levels higher than those years later, around today's levels; we are not even certain that the increase in CO2 is actually caused by human activity; the idea of &quot;global temperature&quot; is nonsensical, any knowledge of meteorology (I teach the subject) shows that a single number does not represent anything meaningful, literally it has no physical meaning, no place in the climate system. We are literally ignoring the existence of climate at the start of discussing climate change.&lt;/p&gt;&#xA;" OwnerUserId="18797" LastActivityDate="2020-01-24T23:45:13.533" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19068" PostTypeId="1" CreationDate="2020-01-25T03:44:54.923" Score="1" ViewCount="81" Body="&lt;p&gt;Could any of you, please, tell me who is the author of this book on Bill Maher's shelf? The book name is &quot;Climate Science&quot; and the cover color seems to be green. I looked for it on the Amazon website to no avail.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jm5cE.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jm5cE.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I appreciate your help.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;" OwnerUserId="18798" LastActivityDate="2020-01-25T03:44:54.923" Title="Author's Name Of A Book On Bill Maher's Shelf" Tags="|climate-change|climate|climatology|reference-request|literature-request|" AnswerCount="0" CommentCount="2" ClosedDate="2020-01-26T16:46:06.253" ContentLicense="CC BY-SA 4.0" />
  <row Id="19069" PostTypeId="1" CreationDate="2020-01-25T04:20:16.670" Score="5" ViewCount="220" Body="&lt;p&gt;During a polar night is there any pattern or consistency to where aurorae australis begin?  I'm assuming they become visible first in the exosphere and descend down to thermosphere.  Do they tend to begin and move from east to west, or west to east or is it entirely random?&lt;/p&gt;&#xA;" OwnerUserId="14986" LastEditorUserId="14986" LastEditDate="2020-01-25T22:02:55.187" LastActivityDate="2020-01-26T11:09:19.873" Title="Where do aurorae australis begin and in which direction do they move?" Tags="|auroras|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19070" PostTypeId="1" CreationDate="2020-01-25T05:58:42.057" Score="5" ViewCount="2370" Body="&lt;p&gt;I wonder how much benefit would a hydroelectrical project built on this inflow bring.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are projects to fill up the Erie, Salton, Qattara and the Dead Sea. But for the Caspian, there is only a proposal for a Panama-like canal with locks - &lt;a href=&quot;https://en.wikipedia.org/wiki/Eurasia_Canal&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Eurasia_Canal&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This picture gives the scale, but not the numbers.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/n9PVV.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/n9PVV.jpg&quot; alt=&quot;Caspian floodmap&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.floodmap.net/?ll=43.334232,43.460796&amp;amp;z=5&amp;amp;e=0&quot; rel=&quot;noreferrer&quot;&gt;https://www.floodmap.net/?ll=43.334232,43.460796&amp;amp;z=5&amp;amp;e=0&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think the Soviets might have done some calculations.&lt;/p&gt;&#xA;" OwnerUserId="18799" LastEditorUserId="18799" LastEditDate="2020-01-25T06:50:02.477" LastActivityDate="2020-01-25T14:11:06.007" Title="How much water will flow into the Caspian Sea if it is connected to the World Ocean?" Tags="|hydrology|geography|geoengineering|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19071" PostTypeId="2" ParentId="19069" CreationDate="2020-01-25T10:04:47.303" Score="-8" Body="&lt;p&gt;Aurora Australis and Aurora Borealis occur as a result of the upper atmosphere being bombarded with sub atomic particles (protons and electrons) from the solar wind. Solar winds are mass ejections from magnetic storms on the sun, and vary in intensity and frequency. These particles are electrically charged and deflected toward the poles by the Earth's magnetic field. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The aurorae have a tendency to be displaced toward the night time side of the Earth and to move very slowly from west to east because the magnetic poles are slightly off-centre and rotate with the rotation of the Earth. Films on TV often show the aurora speeded up, but usually their movement is only barely perceptible to the naked eye. If you can see the background stars moving, the movie has been speeded up. The ones I saw with the naked eye moved very slowly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two main colours. Green is by far the most common, but occasionally the aurora is red. I have seen both from southern England. The red ones are caused by solar wind particles striking and exciting oxygen atoms in the high, upper atmosphere, causing them to emit a reddish light. These particles also vary in velocity, so the more powerful ones are able to reach further down into the atmosphere and stimulate a much stronger emission of green light from nitrogen atoms. This overwhelms the fainter red light from oxygen, so the aurora looks green. They are not often seen from southern England. It sometimes happens, but only in the winter with a very clear sky.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2020-01-25T10:25:41.097" LastActivityDate="2020-01-25T10:25:41.097" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="19072" PostTypeId="2" ParentId="19070" CreationDate="2020-01-25T10:36:02.037" Score="6" Body="&lt;p&gt;Welcome to earth science stack exchange !&lt;/p&gt;&#xA;&#xA;&lt;p&gt;People living along the banks and flat hinterlands in the flooding areas will not be amused of such an enterprise. I would also say that sacrificing all that potentially fertile land might trigger protests. And as the Caspian water table reaches global sea level, power production will go down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mentioned canal would need locks to keep the water from flowing from the Black Sea to the Caspian because the &lt;a href=&quot;https://en.wikipedia.org/wiki/Black_Sea&quot; rel=&quot;noreferrer&quot;&gt;Black Sea&lt;/a&gt; only has a ~50m layer of fresh water over a huge basin of &lt;a href=&quot;https://www.ocean.washington.edu/people/faculty/jmurray/BlackSeaOverview.pdf&quot; rel=&quot;noreferrer&quot;&gt;anoxic salty waters&lt;/a&gt; that contain gases from the decay of organisms. The &quot;&lt;a href=&quot;https://www.nature.com/articles/338411a0&quot; rel=&quot;noreferrer&quot;&gt;interface layer&lt;/a&gt;&quot; is unstable, raising it via an outflow of fresh water could eventually cause a release of gasses like &lt;a href=&quot;https://phys.org/news/2016-09-black-sea-lost-habitable-volume.html&quot; rel=&quot;noreferrer&quot;&gt;hydogen sulfide&lt;/a&gt; in a larger scale. Also, the anoxic water below the boundary layer is highly corrosive to machinery.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Power generation with water in such a large scale is cheaper and more sustainable along fresh water currents or in tidal power stations.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now that was not a real answer, that would have had some math like flooded area  * height difference(28m) * fudge factor for topography and a division by the cross section of the inflow to get a feeling for the time it would take to fill the pan, but it has some background on the setting we're talking about.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope that helps, if not, let me know :-)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: i just realized that much of my answer is somewhat nonsensical because there is a water divide between the two water bodies from where it goes downhill to both sides. While a closed pipe could be imagined for a constant flow and to drive turbines, it doesn not seem very practical. But that's engineering, not my strength ...&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-25T14:11:06.007" LastActivityDate="2020-01-25T14:11:06.007" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19073" PostTypeId="2" ParentId="8267" CreationDate="2020-01-25T12:58:17.800" Score="0" Body="&lt;p&gt;Leaning out of the window with:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I doubt the stone in the OP is the outcome of boring organisms. It rather is a &lt;a href=&quot;https://en.wikipedia.org/wiki/Chert#/media/File:Flint_with_weathered_crust.JPG&quot; rel=&quot;nofollow noreferrer&quot;&gt;cretaceous chert&lt;/a&gt; that fell out of the chalk cliffs (if present) or was washed out on the beach by the ocean. It is very abundant in the area (and elsewhere, e.g. the Baltic). I include the second example by @Orgong here, i think it is a chert, too (maybe not cretacous), just because they are so abundant. Both can be checked if they are cracked open. If they only show a white cortex (outer layer) and the inside is amorphous and any shade of gray to black, then it is clearly a chert.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Chert is a sedimentary rock made of amorphous silica from silica secreting organisms. If you crack open a large one you can even find a complete &lt;a href=&quot;https://depositsmag.com/2017/11/02/humble-flint-sea-urchins-and-the-stories-they-tell/&quot; rel=&quot;nofollow noreferrer&quot;&gt;silicified skeleton of a sea urchin&lt;/a&gt; in it. They form as nodules in the sediment, sometimes in horizons of decimeters, combine with neighbours in the process, form plates, and anyway can have any shape including concave or with holes. Processes are described in detail for example &lt;a href=&quot;https://ocw.mit.edu/courses/earth-atmospheric-and-planetary-sciences/12-110-sedimentary-geology-spring-2007/lecture-notes/ch6.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sidenote: pretty good stuff for practicing stone knapping. Use a dense rounded sandstone as a pounder. And keep an easy wrist. It is all about the speed and angle, not the force. And do practice on a blanket to collect all the small flakes and chips or people will cut their feet when they wade through the remains of the workshop :-)&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-25T15:03:49.677" LastActivityDate="2020-01-25T15:03:49.677" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19074" PostTypeId="1" CreationDate="2020-01-25T18:51:14.863" Score="7" ViewCount="331" Body="&lt;p&gt;There is this &lt;a href=&quot;https://websites.pmc.ucsc.edu/~glatz/field190.html&quot; rel=&quot;noreferrer&quot;&gt;slightly uncombed&lt;/a&gt; simulation &lt;a href=&quot;https://websites.pmc.ucsc.edu/~glatz/geodynamo.html&quot; rel=&quot;noreferrer&quot;&gt;model&lt;/a&gt; of a geomagnetic field reversal, showing multiple poles, a quadrupole or even higher order magnetic field. Earth's magnetic field is mostly described as a dipole and navigation wouldn't work without that, (considerable) local perturbations left aside. But a multipole field is a theoretically valid configuration, as long as no N or S pole remains solo (quadru-, sextu, octupole ...). &lt;a href=&quot;https://ui.adsabs.harvard.edu/abs/2005AGUFMGP41C..01K/abstract&quot; rel=&quot;noreferrer&quot;&gt;Some bodies&lt;/a&gt; in the solar system may have multipole fields.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But for earth's magnetic field, is there actual evidence of multiple poles at a time, from geomagnetic chronolgy, ocean floor or ophiolites, magma flows ? These may be transient events, happening during reversals.&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-26T11:54:36.907" LastActivityDate="2020-02-01T18:49:16.713" Title="Is there evidence of multiple poles (higher order than dipole) in earth's magnetic field?" Tags="|geomagnetism|paleomagnetism|reversals|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19075" PostTypeId="2" ParentId="19024" CreationDate="2020-01-26T04:12:20.177" Score="1" Body="&lt;p&gt;I believe the author's was referring to phenomena like salt diapirs (where mobile salt deposits intrude into heavier overlying sediments).  These produce low hills in the gulf coast region of the United States.  The salt that is moving is not liquid, it is merely mobile.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do not believe the author of the book you reference was referring to sand and mud diapirs as these deposits are not considered &quot;rocks&quot;.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastEditorUserId="8513" LastEditDate="2020-01-26T04:51:37.120" LastActivityDate="2020-01-26T04:51:37.120" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19076" PostTypeId="2" ParentId="19069" CreationDate="2020-01-26T06:29:37.430" Score="7" Body="&lt;p&gt;Auroras start at a distance of 80-200 km above the Earth's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The color of the aurora will be blue/purple if the air molecules in the area below 120 km are excited.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the air molecules in the area from 120-180 km are the ones that gets excited the colour will be yellow/green.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Above 180 km gives the red light in the aurora.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most powerful aurora will in general be 180 degree from the Sun's position and it will move from east to west at the opposite side to where the Sun is.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During powerful auroras the aurora arch can easily cover 270 degrees or more if close to the magnetic poles, if the aurora covers the area away from the magnetic poles the aurora arch will get smaller.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the charged particles from the Sun interact with Earth's magnetic field a powerful ground current will be induced, this can induce DC power in power lines and severely damage the AC power transformers. Should an event like the one that happened on September the first, 1859 (the Carrington event) hit us today we would have major problems with power supply and satellite communication.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can read more about all of this here, &lt;a href=&quot;https://en.wikipedia.org/wiki/Aurora&quot; rel=&quot;noreferrer&quot;&gt;Aurora&lt;/a&gt; and please take a look in the sources there too.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="2470" LastEditDate="2020-01-26T11:09:19.873" LastActivityDate="2020-01-26T11:09:19.873" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19077" PostTypeId="2" ParentId="19044" CreationDate="2020-01-26T07:41:54.713" Score="0" Body="&lt;p&gt;In your question I think you are mixing up metamorphic conditions such as the conditions that gneiss forms from sedimentary rock with the formation of diapirs.  Diapirs occur where a less dense layer of a relatively plastic rock has denser overlying formations create sufficient pressure so that the less dense substance deforms and rises over time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Diapirs of salt occur where thick salt deposits over overlain by dense sedimentary shales and sandstones.  Because of the slowness with which salt deforms the sedimentary deposits will be buried sufficiently deeply that they will have lithified, turning to rock and becoming more dense.  The salt layer will have some trapped water in it that helps the salt to recrystallize as a response to a pressure gradient.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Diapirs can also occur where water saturated sands are overlain by muds (sand volcanoes) or where water saturated clay layers are overlain by dense silts (mud lump islands).  In these cases the layers are relatively shallow and the sands and clays are not lithified.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In conditions of deep burial and high pressure differentials the sedimentary rocks will recrystallize into denser rocks and will deform, producing folds in some lithologies and faults in other rock types.  The slow speed of the deformations and high pressures and temperatures (mostly due to deep burial) give the mineral grains the rocks are made of time to recrystallize and move around each other.  Only if this sub-microscopic recrystallization is not happening fast enough will there be faulting in a layer.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2020-01-26T07:41:54.713" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19078" PostTypeId="2" ParentId="9246" CreationDate="2020-01-26T18:33:44.733" Score="0" Body="&lt;p&gt;I'm guessing here, but there are two things that seem to mechanically form the organized concentrated air rivers that are jet streams.  I've despaired to find no good meterologist site or link that goes beyond grand vague hand waving gestures that mostly over-explain Coriolis Forces and irrelevant complexities.  Here's how I think the actual organized streams are formed.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We need to be careful about postulating that different temperatures cause the actual streams.  I don't think that's a useful perspective.  Certainly, different temperatures are required to set up organized Polar, Ferrel and Hadley cells, but the heart of the explanation for the actual stream formation is looking at only momentum and drag.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the surface wind of a Ferrel Cell (not the somewhat opposite flowing high altitude wind of the same  Ferrel Cell) blows northward, it's earth-based radius decreases.  It's becomes closer to the spin axis of the earth.  That means that its relative velocity is always more eastward than that of the air it is joining.  That's the Coriolis Force. Ok, so we get northeastern lower winds throughout the band of that Ferrel Cell, progressively becoming more eastwardly farther north.  But why the sudden discontinuous increase in velocity at the northern edge of the Ferrel Cell that produces a jet stream?  Well.  Because all throughout the transit that those low level winds negotiated on their northward trek within that Ferrel Cell, they had to gently push more eastward for every inch north they moved against the drag of the atmosphere they encountered. Their acceleration to the east was limited by atmospheric drag. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But suddenly these northward winds are stopped from going further north when they encounter the Polar cell and are forced to deflect directly eastward. They are no longer dragged down by the slower rotating atmosphere north of them because they are moving only eastward.  This means that the atmosphere that would normally drag down these northeastward tending winds is mostly made of their neighbor Ferrel Cell winds, that had been northeastwardly parallel to them for a while, that are similarly suddenly deflected due east by encountering the obstruction of the Polar Cell.  Now, at the northern border of the Ferrel Cell, these winds all line up moving east as they begin to rise up towards the top of the Ferrel Cell and turn around back to the south to continue their cycle in the Ferrel circulation Cell, their eastward momentums now all lined up together fully aligned with each other along the lines of latitude (parallel to the equator) and pushing forth with their excess momentum in line concentrated in a much smaller area (than the circumferal distance of the Polar Cell and Ferrel Cell border).  The eastward change in momentum has been concentrated at this border by having the Ferrel Cell winds line up trying to accelerate each other because they are forced to suddenly turn east.  A visual picture of a similar idea is five people thrashing through a forest line abreast - like the low level northeasterly Ferrel Cell winds.  Then, suddenly they turn 90º and have a lot less thrashing to do to get through the forest because of their alignment - like those Ferrel Cell winds when they turn to line up behind each other at the circulation cell boundary.  The atmosphere these winds encounter that would normally limit their eastward acceleration is now made up of similar Ferrel Cell winds trying to accelerate eastward during the big turn back to the south.  The result is a reduction in atmospheric drag in relatively short distance.  Boom:  Jet stream.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You may wonder why it would be that at the northern border of, say, the Ferrel Cell where there is no longer a northward component of velocity would still provide an eastward force to prople the jet stream since the eastward component of the Coriolis Force disappears when the northward velocity goes to zero.  It's because of lag.  The eastward pressures are not fully equalized instantly when the air stops moving northeastward and is deflected due east.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If all this is the case, then why does the subtropical jet also move east?  Only air that is approaching a cell border can produce a jet; not air that is retreating from such a border because of the mechanism described above.  So only the upper air of the Hadley cell can contribute to a jet stream  at the border between the Ferrel and Hadley cells.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, why doesn't the southern flowing air in the upper reaches of the Ferrel Cell create a westward moving jet?  If you examine the profile view of the circulation cells, notice the altitude where the reversal from north/south occurs.  In the both the Polar and Hadley cells, due to the odd sloped frontal border of the various cells, the reversals that should spawn westward blowing jet streams happen at low altitude where too many disturbances prevent organized flow.  Remember even the low altitude portion of the Ferrel Cell can't form a jet stream until it has shifted up into the high region of the cell at the turn reversal. Furthermore, the Ferrel Cell runs backwards.  That is, it is thermally indirect, so not driven by disparities in surface heating like the Polar and Hadley Cells, hence it is weaker, driven by its neighboring cells, which are thermally direct.  Occaionally, a west flowing subtropical jet forms from these normally turbulent regions if conditions are just right, but not normally.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It should be remembered that on a planetary scale these jets are rather weak, broken, discontinuous, and easily disrupted.  For example, if global warming reduces the sharpness of the temperature variation between the Polar Cell and the Ferrel Cell, that border becomes less defined and can undulate down into the central US in what the news calls a Polar Vortex.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alas, I can't back any of this up because I've not seen it anywhere.  This could all be wrong, but it seems straight forward enough to be plausible.&lt;/p&gt;&#xA;" OwnerUserId="18805" LastEditorUserId="18805" LastEditDate="2020-01-26T18:38:45.710" LastActivityDate="2020-01-26T18:38:45.710" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19079" PostTypeId="2" ParentId="9246" CreationDate="2020-01-27T01:53:40.280" Score="0" Body="&lt;p&gt;Are you asking about the energy from the sun causing the circulation cells to circulate?  If so, that's the easy part.  I sound like I know what I'm talking about, but I'm not really a reliable source.  But here's my analysis:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sun heats the earth at the equator at steep angles, thus providing a lot of heat to the air at the equator.  This air expands and grows like a mountain over the equator.  Since the air in the mountain has the same mass as before (same number of molecules), its weight on the ground would be the same.  But it is not.  The mountain of expanded air in the high atmosphere above the equator spills downhill northward because the top of the less expanded atmosphere to the north is lower.  But as this downhill falling air moves north its time spent at cool altitudes and the less direct rays of the sun at higher latitudes cause it cool and become more dense.  It becomes more dense than the air it falls over on the north edge of the Hadley Cell, so it sinks down.  Why does it move south to complete the cycle? Because the continually rising column of air encircling the equator causes a constant low pressure condition on the ground as it rises up and spills off the mountain.  If the air spills off the equatorial mountain of air, the mountain is lighter than it was before.  That the mountain got high to start with would not change its weight or the pressure at the equator.  The pressure at the equator is always low because the rising mountain of expanding air is forever spilling downhill to the north and causing fewer molecules and atoms of atmosphere to occupy that mountain that sits on the equator.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note, the the Polar Cell functions just like the Hadley Cell.  But you might notice that the Ferrel Cell runs backwards against the dynamics I just described.  That's because both the Hadley Cell and the Polar Cells are &quot;thermally direct,&quot; or run the right way.  The Ferrel cell is not run by the dynamics I just described because it is &quot;thermally indirect,&quot; powered and supported by the boundary effects of bumping up against the Hadley and Polar Cells.  I don't have a good grasp on the thermally indirect cell being driven by its neighbor cells, but I have a feeling it has to do with atmospheric lifting at the north edge of the Ferrel Cell caused by the Polar cell ( and the converse at the border with the Hadley Cell), perhaps encouraging upper atmospheric southern downhill flow, but boy that's a reach.&lt;/p&gt;&#xA;" OwnerUserId="18805" LastActivityDate="2020-01-27T01:53:40.280" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19080" PostTypeId="2" ParentId="13972" CreationDate="2020-01-27T05:55:32.930" Score="3" Body="&lt;p&gt;The following sources helped me understand these landforms - hopefully they can help you too :)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the &lt;a href=&quot;https://www.miranda-shorebird.org.nz/natural-history/chenier-plains&quot; rel=&quot;nofollow noreferrer&quot;&gt;Miranda Shorebird Centre&lt;/a&gt;: The Miranda-Kaiaua cheniers are first formed as sand and cockle-shell bars on the foreshore or intertidal flats. The bars are then moved landward by wave action. Eventually the bars attain sufficient height to withstand such wave action.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;https://earthobservatory.nasa.gov/images/78980/strandplain-coastal-peru&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA's Earth Observatory&lt;/a&gt;: Strandplains are built by successive additions of beach sand, usually from some nearby source. Each ridge shows the position of a prior shoreline.&lt;/p&gt;&#xA;" OwnerUserId="18806" LastActivityDate="2020-01-27T05:55:32.930" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19081" PostTypeId="2" ParentId="13972" CreationDate="2020-01-27T14:15:19.527" Score="0" Body="&lt;p&gt;Pebbles and other mostly non-biological debris are heaped up on the beach by wave action. Then either the sea retreats or the land rises, and these features are left high and dry to become part of the landscape. An example of land rising may be found in Scotland, where relieved of the burden of ice a couple of kilometres thick, the land is still rising more than 10,000 years after the last ice age ended. Other phenomena may cause the land to rise, but the removal of an ice burden is a common one.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-27T14:15:19.527" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19082" PostTypeId="2" ParentId="14216" CreationDate="2020-01-27T15:59:21.830" Score="2" Body="&lt;p&gt;The first department that comes to mind is obviously academia, i.e. faculty or research positions at universities. However, there are many other career paths available (hopefully: there are not enough academic positions for every student completing a Ph.D...). For volcanologists, there is actually a nice site called &lt;a href=&quot;https://volcanologistsoutsideacademia.wordpress.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;volcanologists outside academia&lt;/a&gt;. As the name suggests, it compiles various testimonies about people who got a Ph.D. in volcanology but now work outside academia. They have also conducted a survey to gather more data. The results show that there are very diverse employment possibilities, including (but not restricted to):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Outreach/science communication&lt;/li&gt;&#xA;&lt;li&gt;Museums&lt;/li&gt;&#xA;&lt;li&gt;Academic publishing&lt;/li&gt;&#xA;&lt;li&gt;Data analysis&lt;/li&gt;&#xA;&lt;li&gt;Material science&lt;/li&gt;&#xA;&lt;li&gt;Instrument companies&lt;/li&gt;&#xA;&lt;li&gt;Tourism...&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I'm not sure for igneous petrologists/geochemists, but I think the possibilities are pretty close.&lt;/p&gt;&#xA;&lt;p&gt;Edit: I just realized I completely forgot to mention volcano observatories, which represent a &amp;quot;large&amp;quot; source of employment for the community (relative to its size). IAVCEI's Early Career Network has put up a &lt;a href=&quot;https://www.youtube.com/channel/UC_OnswTU2k8WZuOmdCD22qQ/videos&quot; rel=&quot;nofollow noreferrer&quot;&gt;series of videos&lt;/a&gt; where observatory workers describe their job. Another series about careers in academia is planned, so stay tuned!&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2020-10-13T15:57:25.010" LastActivityDate="2020-10-13T15:57:25.010" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19083" PostTypeId="1" CreationDate="2020-01-28T07:00:16.327" Score="1" ViewCount="280" Body="&lt;p&gt;I've heard a bunch of impractical proposals for ways to sequester carbon:  pump CO2 gas into the ground, grow trees for the sole purpose of burying them underground where they won't decompose...   and these proposals all seem impractical to me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By contrast, it seems quite doable to allow people to consume single-use plastics, and dispose of them in well managed landfills.  (I wouldn't exactly say we should &lt;em&gt;encourage&lt;/em&gt; the practice, not until we have bioplastics in widespread use and green energy powering plastic production).  Stringent efforts should be made to ensure the plastic is not burnt and is kept out of the marine environment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plastic is very chemically stable, it won't decompose and form methane or anything else, it won't bubble up to the surface, and mixed in with garbage it becomes unattractive for future generations to dig it up.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm also making the assumption that any oil not used for plastic production would be used instead in the transport industry or at least somewhere where it'll be put straight into the atmosphere. I think it's naive to think that if I forgo my plastic drinking straw, there'll be one more drop of oil remaining forever in the ground - it won't be left in the ground, instead it'll be made available to the transport industry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've tried to get an answer to this question from New Scientist, Australia's Dr Karl and basically every chemist or physicist I encounter and no-one can explain why I'm wrong.  So it seems to me governments everywhere who are banning single-use plastics are doing the opposite of what they should be doing.&lt;/p&gt;&#xA;" OwnerUserId="18812" LastEditorUserId="18812" LastEditDate="2020-01-30T00:32:44.250" LastActivityDate="2020-01-30T00:32:44.250" Title="Shouldn't we encourage consumption of single-use plastics? Plastic is a good way to sequester carbon" Tags="|climate-change|plastic|" AnswerCount="3" CommentCount="10" ClosedDate="2020-01-28T13:51:39.020" ContentLicense="CC BY-SA 4.0" />
  <row Id="19084" PostTypeId="2" ParentId="18509" CreationDate="2020-01-28T08:39:01.793" Score="1" Body="&lt;p&gt;I did download and process some of the NEX files a year or so ago. Maybe there is a more efficient way to do that now, but what I used is this R script to download the files:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;library(RCurl)&#xA;opts = curlOptions(proxy='http://10.xxx.xxx.xx:xxxx', userpwd = &quot;you needed NEXGDDPusr:pswd at that time&quot;, netrc = TRUE)&#xA;&#xA;&#xA;var = c(&quot;pr&quot;,&quot;tasmax&quot;,&quot;tasmin&quot;) ##here the variables&#xA;rcp = c(&quot;rcp45&quot;, &quot;rcp85&quot;) ##here the scenarios&#xA;mod= c(&quot;CCSM4&quot;, &quot;GFDL-CM3&quot;, &quot;IPSL-CM5A-MR&quot;, &quot;MIROC5&quot;,  &quot;inmcm4&quot;)##here the climate models&#xA;year=c(seq(2040,2060,1)) # here the time period&#xA;&#xA;for (v in var) {&#xA;  for (r in rcp) {&#xA;    url&amp;lt;- paste0( 'http://nasanex.s3.amazonaws.com/NEX-GDDP/BCSD/', r, '/day/atmos/', v, '/r1i1p1/v1.0/', sep='') ##here the url (please, note this might be different now)&#xA;    for (m in mod) {&#xA;      for (y in year) {&#xA;        nfile&amp;lt;- paste0(v,'_day_BCSD_',r,&quot;_r1i1p1_&quot;,m,'_',y,'.nc', sep='')&#xA;        url1&amp;lt;- paste0(url,nfile, sep='')&#xA;        destfile&amp;lt;-paste0('D:/NASA_NEX/',r,'/',v,'/',nfile, sep='') ##destination folder&#xA;        bin &amp;lt;- getBinaryURL(url1, .opts = opts)&#xA;        writeBin(bin, destfile)&#xA;        Sys.sleep(1)&#xA;        gc()&#xA;      }}}}&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;This, however downloads the global files. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second stage would be to extract the data for the point you need. For doing this in R you can use something &lt;a href=&quot;https://rpubs.com/markpayne/358146&quot; rel=&quot;nofollow noreferrer&quot;&gt;like this&lt;/a&gt;. In alternative you can use &lt;a href=&quot;https://code.mpimet.mpg.de/projects/cdo/wiki&quot; rel=&quot;nofollow noreferrer&quot;&gt;CDO&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="8087" LastActivityDate="2020-01-28T08:39:01.793" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19085" PostTypeId="2" ParentId="19083" CreationDate="2020-01-28T09:49:06.883" Score="11" Body="&lt;p&gt;Plastic isn't a good way to sequester carbon the sense that this term is usually meant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Carbon sequestration is normally assumed to mean&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;[...] the long-term removal, capture or sequestration of carbon dioxide &lt;em&gt;from the atmosphere&lt;/em&gt; to slow or reverse atmospheric CO2 pollution and to mitigate or reverse global warming.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(From &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_sequestration&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;, my emphasis.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is not how plastic production works: the great majority of plastic is made from petrochemicals.  So almost all plastic is made from fossil carbon, not from carbon extracted from the atmosphere recently.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With plausible assumptions about the energy used in making plastic and its source, then turning fossil carbon into plastic which is then not burnt is probably better in terms of carbon emissions than just putting the fossil carbon straight into the atmosphere.  But it's &lt;em&gt;worse&lt;/em&gt; (again in terms of carbon emissions) than just not making the plastic at all.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Note that there have been plastics made from plant materials, and many early plastics were made like that: &lt;a href=&quot;https://en.wikipedia.org/wiki/Celluloid&quot; rel=&quot;noreferrer&quot;&gt;Celluloid&lt;/a&gt; is a good example.  I thought &lt;a href=&quot;https://en.wikipedia.org/wiki/Bakelite&quot; rel=&quot;noreferrer&quot;&gt;Bakelite&lt;/a&gt; was as well, but it turns out it's the first one that wasn't.&lt;/p&gt;&#xA;" OwnerDisplayName="user18801" LastEditorUserId="18081" LastEditDate="2020-01-28T12:27:33.080" LastActivityDate="2020-01-28T12:27:33.080" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19087" PostTypeId="2" ParentId="19083" CreationDate="2020-01-28T12:04:49.133" Score="-6" Body="&lt;p&gt;tib is absolutely right in what he says, but damage to the environment and more specifically to wildlife is another reason for greatly reducing our use of plastics made from fossil hydrocarbons. Those made from biological sources are better, but have their disadvantages too. Some biodegradable plastic bags, for instance, biodegrade while the contents are still in them if you don't use them straight away.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The worst damage is done when the plastic gets into the ocean. Turtles and other marine creatures mistake plastic bags for jellyfish and swallow them. Seabirds occasionally feed them to their young or incorporate plastic items in their nests which entangle their young. Other creatures such as dolphins,sharks and turtles become entangled in plastic rope or fishing nets, and die of suffocation. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plastic bottles are among the worst forms of plastic pollution. The sheer number of them is staggering. Tap water is quite healthy; we don't need to go around all day sipping water from plastic bottles as though we were afraid of drying out like a slug on a hot pavement. Then there is the problem of plastic micro-particles produced by the breakdown of larger items. It has yet to be established exactly how harmful these micro-particles are, but they enter the human food chain when we eat sea food.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The best biodegradable bags are made of paper, so we should return to much greater use of paper bags. I know trees have to be cut down to make paper, but done properly the forest or plantation will eventually regenerate. Packaging of all sorts is usually too lavish, and needs to be reduced.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-28T12:04:49.133" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19088" PostTypeId="2" ParentId="19083" CreationDate="2020-01-28T12:37:29.397" Score="3" Body="&lt;p&gt;Plastic waste is a &lt;a href=&quot;https://advances.sciencemag.org/content/3/7/e1700782.full&quot; rel=&quot;nofollow noreferrer&quot;&gt;problem&lt;/a&gt; already and it is growing quickly. Huge &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Pacific_garbage_patch&quot; rel=&quot;nofollow noreferrer&quot;&gt;rafts of plastic flood&lt;/a&gt; the ocean, they end up in the foodchain, killing huge numbers of animals, even &lt;a href=&quot;https://www.onegreenplanet.org/animalsandnature/marine-animals-are-dying-because-of-our-plastic-trash/&quot; rel=&quot;nofollow noreferrer&quot;&gt;endangering species&lt;/a&gt;, and &lt;a href=&quot;https://www.ciel.org/news/plasticandhealth/&quot; rel=&quot;nofollow noreferrer&quot;&gt;human health&lt;/a&gt;. With &lt;a href=&quot;https://science.sciencemag.org/content/359/6371/eaam7240.full&quot; rel=&quot;nofollow noreferrer&quot;&gt;ocean deoxygenation&lt;/a&gt; coming into view and the &lt;a href=&quot;https://committee.iso.org/files/live/sites/tc61/files/The%20Plastic%20Industry%20Berlin%20Aug%202016%20-%20Copy.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;sheer amount&lt;/a&gt; of plastic being produced (as @tfb pointed out by releasing CO2) and &lt;a href=&quot;https://www.nationalgeographic.com/news/2017/07/plastic-produced-recycling-waste-ocean-trash-debris-environment/&quot; rel=&quot;nofollow noreferrer&quot;&gt;little recycling&lt;/a&gt; taking place, the suggestion to deliberately use one way products to eventually sequester CO2 must be regarded as &lt;strong&gt;not sustainable&lt;/strong&gt; as long as plastic production is fossil fuel based, little recycling takes place and the disposal poses such huge risks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;IOW: this is not a good idea.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: one can further search man-made soils, effects of landfills from waste disposal, and their impact on fresh water, farming, health, etc. as well as the carbon footprint of plastic production. There is work on these subjects.&lt;/p&gt;&#xA;" OwnerDisplayName="user18607" LastEditorDisplayName="user18607" LastEditDate="2020-01-28T13:28:15.103" LastActivityDate="2020-01-28T13:28:15.103" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19089" PostTypeId="1" CreationDate="2020-01-28T15:49:25.657" Score="1" ViewCount="382" Body="&lt;p&gt;The asteroid which created the Vredefort impact crater in South Africa is estimated to have been between 10 and 16 km in diameter (the uncertainty is due to the age of the crater, which is more than 2 billion years). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming the maximum estimate is correct, how deep could this asteroid have penetrated into the Earth's crust, and would the resulting crater have become filled or partly filled with magma like some of those on the moon?  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason no mass extinction is associated with it is that at that time the most complex life on Earth was only single-celled. It should be remembered that the crust was thinner in those days, as was the case with the magma-filled craters on the moon. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another important factor is the sped of the asteroid at the moment of impact, which we cannot know,therefore an average of mega-meteorite velocities will do. It is important to read this question carefully before answering,otherwise I have to keep repeating myself.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="6" LastEditDate="2020-01-29T09:15:16.540" LastActivityDate="2020-01-29T09:15:16.540" Title="How deep could the Vredefort asteroid have penetrated?" Tags="|asteroids|impact-craters|continental-crust|" AnswerCount="1" CommentCount="2" ClosedDate="2020-01-29T03:01:27.593" ContentLicense="CC BY-SA 4.0" />
  <row Id="19090" PostTypeId="2" ParentId="19089" CreationDate="2020-01-28T20:26:01.960" Score="3" Body="&lt;p&gt;10–16 km&lt;/p&gt;&#xA;&#xA;&lt;p&gt;there is an interesting equation that demonstrates an rocky impactor hitting rock does not penetrate further than its diameter. Basically because a meteorite and the rock it hits have similar density several things cancel out so depth of penetration maxes out at the diameter of a spherical projectile. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://books.google.com/books/about/Impact_Cratering.html?id=nZwRAQAAIAAJ&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://fas.org/sgp/othergov/doe/lanl/lib-www/sand/972426.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source 2&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OCDlr.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OCDlr.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;image from Wikipedia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is more about impact craters in general. &#xA;&lt;a href=&quot;https://www.lpi.usra.edu/publications/books/CB-954/chapter3.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.lpi.usra.edu/publications/books/CB-954/chapter3.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Whether it hits on land or the ocean does not matter much either, although oceanic crust is thinner it is also denser, the mantle is even denser still so if it reaches the mantle it should penetrate even less than it would penetrating only crust. That said oceanic crust is only 5-10km in thickness so reaching the asthenosphere is completely possible. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also keep in mind the depth of a crater is different than the depth of the penetration, a penetrator can generate a temporary crater deeper than it penetrated due to shockwave deformation, much like how a you can use your finger to push a depression into a balloon without penetrating it at all.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would it fill with lava absolutely (at least partially) , just from the local rock melted from the impact alone. &lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="6" LastEditDate="2020-01-29T08:52:59.383" LastActivityDate="2020-01-29T08:52:59.383" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19091" PostTypeId="1" AcceptedAnswerId="19092" CreationDate="2020-01-28T23:46:17.627" Score="1" ViewCount="171" Body="&lt;p&gt;The Citarum river seems to pass through Bandung. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Cikapundung_River&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cikapundung River&lt;/a&gt; seems to empty into the Citarum, but this means Citarum starts somewhere else, right?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4S6Dc.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4S6Dc.jpg&quot; alt=&quot;Citarum&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried to follow it in a map. It seems to end in the sea and pass a national park (Cagar Alam Gunung Tangkuban Perahu) in between, but where does it actually start?&lt;/p&gt;&#xA;" OwnerUserId="18817" LastActivityDate="2020-01-29T05:18:43.200" Title="What is the origin of the River Citarum on Java, Indonesia?" Tags="|geography|rivers|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19092" PostTypeId="2" ParentId="19091" CreationDate="2020-01-29T05:12:08.217" Score="1" Body="&lt;p&gt;The &lt;a href=&quot;http://citarum.org/en/about-us/citarum-facts.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Citarum River&lt;/a&gt;,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;originates in Situ Cisanti located at the foot of Mount Wayang, which lies to the south of the city of Bandung, and travels to the north until it empties into the Java Sea. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.bandung-guide.com/2017/11/situ-cisanti-hidden-lake.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Situ Cisanti&lt;/a&gt; is a artificial lake, about 5 to 10 ha in size, depending on which sources one reads. It is fed by &lt;a href=&quot;https://travelingyuk.com/situ-cisanti/188674/?utm_source=idle&amp;amp;utm_medium=dekstop&amp;amp;utm_campaign=reload&quot; rel=&quot;nofollow noreferrer&quot;&gt;seven springs:&lt;/a&gt; Citarum, Cikoleberes, Cikahuripan, Cihaniwung, Cisadane, Cikawudukan, and Cisanti springs. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The picture below shows the designated origin of the Citarum River.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eBUy3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eBUy3.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Aerial view of the lake.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hp7J6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hp7J6.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2020-01-29T05:18:43.200" LastActivityDate="2020-01-29T05:18:43.200" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19093" PostTypeId="1" CreationDate="2020-01-29T18:36:57.397" Score="1" ViewCount="42" Body="&lt;p&gt;I'm writing my thesis on modelling extreme rainfall and I'm still struggling to find a good research question. I have asked a similar question before &lt;a href=&quot;https://earthscience.stackexchange.com/questions/18800/research-question-for-modelling-extreme-rainfall-event-with-coupled-2d-surface-a&quot;&gt;in this post&lt;/a&gt;. Maybe you guys can give me some ideas on what a good research question could be. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I have fixed is the approx. 12km² area, a high resolution DEM and landcover, a lot of different rainfall events with a coarse spatial and temporal resolution and a very good model that gives me the height of flooded areas. The rainfall data I have is one value (i.e 20mm) for a reccurance intervall in years and duration period (i.e 1hour) and a 70km² large area. The value represents the mean precipitation volume for the whole area and time period&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I guess I could just run the model for a couple of events but then I only get a couple of results. That maybe interesting but I feel like this is not reasearch. Its just running the software.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can use rain events that cover the whole area and modify the event so that intensity is concentrated on certain parts of my study area. I.e I can assume that the north of my study area get 30mm rain and the south only 10mm which should have a dramatical influence on the model for the north. Than I can say that the spatial resolution of rainfall data should be as high as possible so that towns have a better data infrastructure for managing flood protection. But that's also kind of self evident.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And than I can do the same for temporal variability. I could assume that the 10mm in the 1hour period hit my area in the first 15min and the second half at minute 45 and could come to the same conclusion that a high temporal resolution would be nice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I came up so far seems very basic... Does anyone have good ideas for an interesting research questions?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Best regards&lt;/p&gt;&#xA;" OwnerUserId="18169" LastActivityDate="2020-01-29T18:36:57.397" Title="struggling to find a good research question in rainfall runoff modelling" Tags="|hydrology|models|" AnswerCount="0" CommentCount="3" ClosedDate="2020-02-03T03:26:25.740" ContentLicense="CC BY-SA 4.0" />
  <row Id="19094" PostTypeId="1" CreationDate="2020-01-30T01:23:18.103" Score="8" ViewCount="666" Body="&lt;p&gt;To what extent do the levels of UVA, UVB and UVC radiations on the earth surface increase during &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_flare&quot; rel=&quot;noreferrer&quot;&gt;solar flares&lt;/a&gt;?&lt;/p&gt;&#xA;" OwnerUserId="587" LastEditorUserId="587" LastEditDate="2020-01-30T15:43:44.300" LastActivityDate="2020-01-30T19:05:28.910" Title="To what extent do the levels of UVA, UVB and UVC radiations on the earth surface increase during solar flares?" Tags="|sun|uv-light|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19095" PostTypeId="2" ParentId="19094" CreationDate="2020-01-30T11:14:58.360" Score="-4" Body="&lt;p&gt;Solar flares are very variable in size and position. A small one on the edge of the sun's disc would have no effect on Earth, but I presume you mean a large one. UVC would be stopped by the ozone layer, so no increase there. UVB gets through the atmosphere with difficulty, so there might be a small increase there, but nothing to worry about. The atmosphere is completely transparent to UVA, so there could be a significant increase with a very large flare. You wouldn't know this unless you followed the TV weather announcements of ultra-violet hazard. If it happened to be cold and wet in your part of the world it wouldn't affect you unless you were in the habit of sunbathing in single-figure temperatures, lowering cloud and pouring rain. Not many people do this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More worrying for most people would be the flare's effect on satellites and communications, or even to the electricity grid in the event of a really large coronal mass ejection. The arrival of huge amounts of charged particles emitted by a flare creates electric currents in the atmosphere which in the most severe cases have been known to shut down electricity grids for many hours.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-01-30T11:14:58.360" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19096" PostTypeId="2" ParentId="19074" CreationDate="2020-01-30T11:35:33.393" Score="1" Body="&lt;p&gt;The simple answer is YES.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Earth's magnetic field is generated by a self-exciting dynamo in the fluid outer core. The interaction between electric currents and liquid motion sustain this field which is largely oriented along the rotation axis, since this rotation exerts constraints on the convection pattern. The dynamo field is largely dipolar but since the fluid circulation and current system is not perfectly symmetrical there arise smaller, non-dipole components which also emerge at the Earths surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Geophysical models describe two magnetic poles: first, the points where the north and south poles of the main (model) dipole outcrop at the Earth's surface and secondly, the points where the (observable) magnetic inclination of the field is vertical - the dip poles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is of course only one N and one S pole for the main dipole. These do not correspond to any special places on the Earth's surface - they are simply optimum mathematical solutions to the field that we observe and model. On the other hand, there can be several N and several S dip poles since the non-dipole field is complex and the field may also be perturbed by local geology.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All these theoretical and observable poles move with time, so there is no point is erecting a pillar or more glamorous monument to mark their position since the next day they will have wandered to different places.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During a geomagnetic reversal the main dipole decays to zero and all that is left is the weak and irregular, non-dipole field giving rise to numerous dip poles scattered over the Earth's surface.&lt;/p&gt;&#xA;" OwnerUserId="18822" LastActivityDate="2020-01-30T11:35:33.393" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19097" PostTypeId="2" ParentId="19094" CreationDate="2020-01-30T18:40:03.837" Score="9" Body="&lt;p&gt;During a powerful solar flare the amount of x-ray radiation can increase up to 110% in the boundry layer of the atmosphere/space,very little of this will reach the earths surface but it can be measured from high flying planes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;UVC is stopped by the upper layer of the atmosphere so this will never reach the ground,It might be possible to measure some UVC in antarctica because of the ozone hole but it is very weak so one will need special equipment to measure it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;UVB will change very little during a solar flare and only in the shortest wavelenght of the UVB spectrum will additional radiation be measurable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;UVA radiation will not change at ground level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During a solar flare only the shorter wavelenghts of the electromagnetic spectrum will be affected,hard x-rays the most and the longer wavelenghts will be less affected.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;source &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2005JA011507&quot; rel=&quot;noreferrer&quot;&gt;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2005JA011507&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;source for more detailed information &lt;a href=&quot;https://en.wikipedia.org/wiki/Ultraviolet&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Ultraviolet&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xynzd.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xynzd.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;i do not have the source for this picture but i think it is free to use.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6258" LastEditDate="2020-01-30T19:05:28.910" LastActivityDate="2020-01-30T19:05:28.910" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19098" PostTypeId="1" CreationDate="2020-01-31T18:03:34.400" Score="5" ViewCount="50" Body="&lt;p&gt;I would like to assess climate change impacts on Protected Areas (e.g. natural reserves, national parks) for Mediterranean countries. I found easily future data from several Global Circulation Models with high resolution (using statistical downscaling), for instance on WorldClim (&lt;a href=&quot;http://www.worldclim.org/version1&quot; rel=&quot;noreferrer&quot;&gt;http://www.worldclim.org/version1&lt;/a&gt;), which is highly used in ecology. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I just realized that I also could use dynamical downscaling of these models (i.e. Regional Circulation Models), as I am focusing on a specific region. However it also looks like the resolution of these RCM is not much better than the resolution of GCM and that it would be necessary to download outputs from many areas (in order to cover the entire Mediterranean region). Moreover, it also seems to be much more difficult (for an ecologist) to find and download these files.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any interest, at my scale, in using RCM rather than GCM with statistical downscaling?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="18828" LastActivityDate="2020-01-31T18:03:34.400" Title="Climate modelling: statistical downscaling or dynamical?" Tags="|climate-change|climate|climate-models|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19099" PostTypeId="1" CreationDate="2020-01-31T21:00:59.710" Score="3" ViewCount="141" Body="&lt;p&gt;I am almost done creating an app that allows people to create a planting calendar based on garden journals created by people who live within a certain radius of a user. In those garden journals people record how many days it took to reach maturity/harvest among many other things. The whole idea behind this planting calendar app is that people who live near each other share the same average monthly temperature and rainfall with each other. Not only that but they will often also share the same soil type and soil pH. In other words, if person A finished a garden journal about tomato variety X and then determined that planting the variety on date X takes 80 days, then person B living say 10 miles (16 km) away will likely be able to harvest after a roughly similar amount of days if he starts growing the variety on the same date as person A did.&lt;/p&gt;&#xA;&lt;p&gt;My question is: &lt;strong&gt;At what distance will the (micro) climate be so different from the climate of person A that the results of the garden journal of person A will no longer be useful for person B?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I've looked at the average temperatures of two  inland points in the Netherlands and I have determined that if those points are about 50 km apart from each other they hardly differ. But if I compare a location near the sea with a location 50 km inland they do differ by a few degrees. This difference becomes significant after a distance of 20 km inland.&lt;/p&gt;&#xA;&lt;p&gt;This is only the Netherlands, perhaps there are places in the world where larger swathes of land share the same average monthly temperatures.&lt;/p&gt;&#xA;&lt;p&gt;I am trying to determine what the maximum radius should be that I should offer to my web application users. Right now the maximum is set to 500 km or 500 miles. But I think this may be too much and not useful to anyone. However I could be mistaken.&lt;/p&gt;&#xA;&lt;p&gt;I would like to hear your opinion about what the maximum should be.&lt;/p&gt;&#xA;" OwnerUserId="18140" LastEditorUserId="18140" LastEditDate="2022-01-11T02:59:49.410" LastActivityDate="2022-01-11T02:59:49.410" Title="At what distance from a location does the average monthly climate significantly start to differ?" Tags="|meteorology|climate|climate-models|" AnswerCount="0" CommentCount="17" ContentLicense="CC BY-SA 4.0" />
  <row Id="19101" PostTypeId="1" CreationDate="2020-02-01T13:17:10.843" Score="1" ViewCount="6239" Body="&lt;p&gt;The state of the clouds and it can only be one of the three states, solid, liquid, or gas. Which one are clouds?&lt;/p&gt;&#xA;" OwnerUserId="18832" LastEditorUserId="39" LastEditDate="2020-02-04T08:50:01.153" LastActivityDate="2020-02-04T13:13:26.560" Title="In which state of matter exactly are the clouds?" Tags="|clouds|" AnswerCount="2" CommentCount="7" ClosedDate="2020-02-04T13:06:59.813" ContentLicense="CC BY-SA 4.0" />
  <row Id="19102" PostTypeId="2" ParentId="19101" CreationDate="2020-02-01T15:14:31.693" Score="-3" Body="&lt;p&gt;You are mistaken in thinking clouds can only be in one of three states. Cumulus and cumulo-nimbus are mostly made of fine water droplets, but also contain water vapour. Cumulo-nimbus (thundercloud) can also contain ice and ice crystals in its upper layers, and produce hail. Cirrostratus is composed of fine ice crystals at high altitude, as is cirrus.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2020-02-01T16:28:29.653" LastActivityDate="2020-02-01T16:28:29.653" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19103" PostTypeId="2" ParentId="19074" CreationDate="2020-02-01T18:49:16.713" Score="4" Body="&lt;p&gt;It's common for dynamo models to predict a large reduction in the dipole field during a reversal. Proving it in the paleomagnetic record is another matter entirely. To characterize the geometry of the magnetic field, you need several simultaneous measurements, preferably with a good spatial distribution. Instead what you get are relatively infrequent, asynchronous measurements. See &lt;a href=&quot;https://eos.org/editors-vox/polarity-reversals-in-the-earths-magnetic-field&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article by Fabio Florindo&lt;/a&gt; for more details. For what it's worth, though, &lt;a href=&quot;https://www.researchgate.net/publication/228353269_Complex_polarity_reversals_in_a_geodynamo_model&quot; rel=&quot;nofollow noreferrer&quot;&gt;a model by Olson et al. (2011)&lt;/a&gt; with multipolar fields during the transition predicts some observations that are consistent with the &lt;a href=&quot;https://en.wikipedia.org/wiki/Brunhes%E2%80%93Matuyama_reversal&quot; rel=&quot;nofollow noreferrer&quot;&gt;Matayama-Brunhes transition&lt;/a&gt;, including reductions in the intensity of the field and variations in the virtual geomagnetic pole path (VGP) from one site to another (see page 124 of &lt;a href=&quot;https://www.google.com/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=2&amp;amp;ved=2ahUKEwjisJ_sgbHnAhUIr54KHWZLBIcQFjABegQICxAE&amp;amp;url=https%3A%2F%2Fwww.geo.arizona.edu%2FPaleomag%2Fchap07.pdf&amp;amp;usg=AOvVaw1Wh_xLL0SIqGEIgVsAdbbl&quot; rel=&quot;nofollow noreferrer&quot;&gt;this book&lt;/a&gt; for a definition of a VGP).&lt;/p&gt;&#xA;" OwnerUserId="10764" LastActivityDate="2020-02-01T18:49:16.713" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19106" PostTypeId="2" ParentId="14268" CreationDate="2020-02-02T23:42:23.140" Score="7" Body="&lt;p&gt;The medium for a solar flare is plasma, so nothing like that occurs in the Earth's core. The outer core fluid is highly conductive and has a low viscosity, so changes may occur in the core's field, but the mantle has enough electrical conductivity to filter out the more rapid changes (those with periods of roughly a year or less). See &lt;a href=&quot;https://books.google.com/books?hl=en&amp;amp;lr=&amp;amp;id=96APl4nK9lIC&amp;amp;oi=fnd&amp;amp;pg=PR13&amp;amp;ots=O7fUw9M43s&amp;amp;sig=qQnld9cRXy9X1pUcGJn1MVvLjmI#v=onepage&amp;amp;q=filter&amp;amp;f=false&quot; rel=&quot;noreferrer&quot;&gt;Merrill and McElhinny pp 49-51&lt;/a&gt; for details. However, &lt;a href=&quot;https://en.wikipedia.org/wiki/Geomagnetic_jerk&quot; rel=&quot;noreferrer&quot;&gt;geomagnetic jerks&lt;/a&gt; have been observed. These are abrupt changes in the second time derivative of the Earth's magnetic field. Sometimes they are global, although mantle filtering can &lt;a href=&quot;https://academic.oup.com/gji/article/200/3/1336/629906&quot; rel=&quot;noreferrer&quot;&gt;delay the jerk by different amounts at different locations on the Earth's surface&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="10764" LastActivityDate="2020-02-02T23:42:23.140" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19107" PostTypeId="1" AcceptedAnswerId="19531" CreationDate="2020-02-03T03:17:51.470" Score="9" ViewCount="343" Body="&lt;p&gt;Below are two cropped screenshots from the super-cool video &lt;a href=&quot;https://youtu.be/-uOwv_Krqk8&quot; rel=&quot;noreferrer&quot;&gt;Draining Earth's oceans, revealing the two-thirds of Earth's surface we don't get to see&lt;/a&gt; with the oceans &quot;drained&quot; to 4000 and 5000 meters below sea level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We've all read about the magnetic field reversals leaving alternating lines of residual magnetic field trapped in the crust that go in the north-south direction, but I was surprised to see these topographic ripples that extend in the east-west direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What caused these to form?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've added some annotation to indicate the direction of the ripples I think I'm seeing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/O5Rar.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/O5Rar.png&quot; alt=&quot;cropped screen shots from Draining Earth&amp;#39;s oceans, revealing the two-thirds of Earth&amp;#39;s surface we don&amp;#39;t get to see&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2020-02-03T03:23:21.217" LastActivityDate="2020-03-30T18:17:43.890" Title="What causes the &quot;ripples&quot; that extend east-west along the mid-atlantic ridge?" Tags="|topography|ocean-ridge|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19110" PostTypeId="1" CreationDate="2020-02-03T12:16:47.253" Score="8" ViewCount="715" Body="&lt;p&gt;Earth and Venus have a very similar gravity, but the mass of atmosphere on Venus is &lt;em&gt;much&lt;/em&gt; greater (according to &lt;a href=&quot;https://en.wikipedia.org/wiki/Venus#Atmosphere_and_climate&quot; rel=&quot;noreferrer&quot;&gt;this wikipedia article&lt;/a&gt; 93 times larger). I know that the chemical composition and temperature are different, but there is just a lot more matter in the Venusian atmosphere. Why is this?&lt;/p&gt;&#xA;" OwnerDisplayName="user18590" LastEditorUserId="18621" LastEditDate="2020-02-03T13:21:19.110" LastActivityDate="2020-12-18T05:34:18.570" Title="Why is the mass of atmosphere of Venus so much greater than that of the Earth?" Tags="|atmosphere|planetary-science|" AnswerCount="2" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="19112" PostTypeId="2" ParentId="19110" CreationDate="2020-02-03T13:42:32.377" Score="2" Body="&lt;p&gt;It is thought that about 4 billion years ago, Venus had an atmosphere and oceans similar to Earth's. Owing to it's proximity to the sun and the fact that most of its primeval atmosphere was carbon dioxide, it heated up and the oceans evaporated away, causing more greenhouse heating as they did so. Water vapour is a potent greenhouse gas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth's primeval atmosphere was also mainly CO2, but being about 30 million miles further away from the sun it did not experience the runaway greenhouse effect which overheated Venus. The seas did not evaporate into the atmosphere, as they did on Venus, where the water mixed with sulphur dioxide/trioxide to create clouds of sulphuric acid droplets.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another thing which has thinned the Earth's atmosphere is billions of years of sequestration by living things, which have transformed atmospheric CO2 into limestone (CaCO3), other carbonates, and various forms of fossil hydrocarbons (Lange et al., 1983). The photosynthetic organisms which produced the hydrocarbons also produced huge quantities of oxygen, which today makes up 21 percent of our atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you could magically turn all the carbon sequestered away in the rocks back into CO2, and evaporate our oceans so that they went up into the atmosphere, the Earth would be much more like Venus, including the runaway greenhouse effect which has heated Venus's lower atmosphere to 460C. Being much further away from the sun than Venus, Earth would not heat up as much as that, but it would still be too hot for life.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Mars also had an atmosphere similar to Earth's and Venus's, but because of its much weaker gravitational field has been unable to hang onto them. However, the proportions of the gases in the Martian atmosphere are still similar to those on Venus, though far more tenuous.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Lange, M. A. &amp;amp; Ahrens, T. J.(1983)&lt;/strong&gt;:&quot;Shock-Induced CO2-PRODUCTION from Carbonates and a PROTO-CO2-ATMOSPHERE on the Earth&quot;, &lt;strong&gt;LUNAR AND PLANETARY SCIENCE&lt;/strong&gt; XIV, P. 419-420.&#xA;&lt;a href=&quot;http://adsabs.harvard.edu/full/1983LPI....14..419L&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://adsabs.harvard.edu/full/1983LPI....14..419L&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorDisplayName="user18590" LastEditDate="2020-02-04T12:29:50.433" LastActivityDate="2020-02-04T12:29:50.433" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19114" PostTypeId="2" ParentId="17929" CreationDate="2020-02-04T04:52:17.663" Score="4" Body="&lt;p&gt;Traditionally, &lt;a href=&quot;https://en.wikipedia.org/wiki/Haze&quot; rel=&quot;nofollow noreferrer&quot;&gt;haze&lt;/a&gt; has been regarded as,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;an atmospheric phenomenon in which dust, smoke, and other dry particulates obscure the clarity of the sky...&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Sources for haze particles include farming (ploughing in dry weather), traffic, industry, and wildfires...&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Whereas haze often is thought of as a phenomenon of dry air, mist formation is a phenomenon of humid air. However, haze particles may act as condensation nuclei for the subsequent formation of mist droplets; such forms of haze are known as &quot;wet haze&quot; ...&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;In meteorological literature, the word haze is generally used to denote visibility-reducing aerosols of the wet type. Such aerosols commonly arise from complex chemical reactions that occur as sulfur dioxide gases emitted during combustion are converted into small droplets of sulfuric acid. The reactions are enhanced in the presence of sunlight, high relative humidity, and stagnant air flow. A small component of wet-haze aerosols appear to be derived from compounds released by trees, such as terpenes. For all these reasons, wet haze tends to be primarily a warm-season phenomenon.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;A haze can also be considered an atmospheric &lt;a href=&quot;https://en.wikipedia.org/wiki/Colloid&quot; rel=&quot;nofollow noreferrer&quot;&gt;colloid&lt;/a&gt;, where,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;one substance of microscopically dispersed insoluble or soluble particles is suspended throughout another substance.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Examples of atmospheric colloids include: fog, mist, clouds, condensation, smoke and atmospheric particulate matter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The forces behind the suspension of haze particles includes: &lt;a href=&quot;https://en.wikipedia.org/wiki/Coulomb%27s_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;electrostatic interactions&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Brownian_motion&quot; rel=&quot;nofollow noreferrer&quot;&gt;Brownian motion&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Van_der_Waals_force&quot; rel=&quot;nofollow noreferrer&quot;&gt;van der Waal forces&lt;/a&gt;, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Entropic_force&quot; rel=&quot;nofollow noreferrer&quot;&gt;entropic forces&lt;/a&gt;. The effect of these forces on the light (low mass) particles within a haze counter gravity to keep the particles suspended in air.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2020-02-04T05:09:06.363" LastActivityDate="2020-02-04T05:09:06.363" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19115" PostTypeId="1" CreationDate="2020-02-04T12:17:38.433" Score="7" ViewCount="110" Body="&lt;p&gt;This is a broad subject I realize, but I'm looking for specific geologically observed answers of global effects elsewhere, between about 5.96 and 5.33 million years ago when the Mediterranean sea was blocked off from the Atlantic and dried up into the Mediterranean valley or salt flat, or whatever term you like.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Mediterranean sea used to be more connected to the Atlantic than it is today, perhaps not ocean, but the water freely flowed between, perhaps comparable to the gulf of Mexico and Atlantic ocean today.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image of what the continents may have looked like 20 million years ago.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PHK9J.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PHK9J.png&quot; alt=&quot;Europe 20 million years ago&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://infographic.tv/map-europe-20-million-years-ago/&quot; rel=&quot;noreferrer&quot;&gt;Source of image&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;About 6 million years ago, North Africa and Spain collided, blocking any connection between the sea and the ocean and the water and not long after the water dried up - leaving salt deposits that are mined today.   I'm thinking it was a great big mess as well, with limited outlets or inlets - kind of like a massive Salton sea, but . . . I digress.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://phys.org/news/2017-09-geologists-mediterranean-sea-million-years.html&quot; rel=&quot;noreferrer&quot;&gt;Pretty good article here&lt;/a&gt; with some detail but not specifically what I'm looking for.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That much water loss (the current Mediterranean is about 3.75 million km&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt; (900,000 cubic miles) of water which corresponds to about 1.2 meters (4 feet) of sea level rise), so sea level rose about 1.2 meters 5.96 million years ago and then gave back those 1.2 meters (4 feet) when the Mediterranean refilled.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Question is, are there any observed global effects from that period either beginning or ending?  Any distinct changes elsewhere on Earth either 5.96 million years ago or 5.33 million years ago?    I'm mostly curious if this event was large enough to have a global effect.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastEditorUserId="18081" LastEditDate="2020-02-04T13:10:02.597" LastActivityDate="2020-02-04T13:10:02.597" Title="Are there any known global effects of the Mediterranean sea evaporation and refilling?" Tags="|geology|climate|mediterranean|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19116" PostTypeId="1" AcceptedAnswerId="23587" CreationDate="2020-02-04T12:40:01.280" Score="13" ViewCount="2366" Body="&lt;p&gt;Years ago I learned that the &lt;a href=&quot;https://en.wikipedia.org/wiki/Snow_Dome_(Canada)&quot; rel=&quot;noreferrer&quot;&gt;Columbia ice field was North America's triple divide point&lt;/a&gt;: water flowing from this ice field could drain into the Artic, the Pacific, and the Atlantic Ocean. Something I never questioned. Today I came upon this map, and was surprised to see that the triple point was actually further south, close to the USA/Canada border:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XYDww.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XYDww.png&quot; alt=&quot;Major continental divides&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I looked it up and found about &lt;a href=&quot;https://en.wikipedia.org/wiki/Triple_Divide_Peak_(Montana)&quot; rel=&quot;noreferrer&quot;&gt;Triple Divide Peak&lt;/a&gt;. The article has another, more precise map:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Ng75G.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ng75G.png&quot; alt=&quot;A map of North American drainage basins/divides&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So it appears that there are actually two triple points. That led me to search which ocean Hudson Bay belongs to... and this is where it gets tricky. Citing various sources, &lt;a href=&quot;https://en.wikipedia.org/wiki/Hudson_Bay&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia says&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Hudson Bay is often considered part of the Arctic Ocean; the International Hydrographic Organization, in its 2002 working draft of Limits of Oceans and Seas defined the Hudson Bay, with its outlet extending from 62.5 to 66.5 degrees north (just a few miles south of the Arctic Circle) as being part of the Arctic Ocean, specifically &amp;quot;Arctic Ocean Subdivision 9.11.&amp;quot; Other authorities include it in the Atlantic, in part because of its greater water budget connection with that ocean.&lt;/p&gt;&#xA;&lt;p&gt;Some sources describe Hudson Bay as a marginal sea of the Atlantic Ocean, or the Arctic Ocean.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So, my questions are: &lt;strong&gt;Which objective criterion could be used to settle this dispute? Considering this criterion, which ocean Hudson Bay belongs to?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2023-05-16T14:22:47.477" Title="Is Hudson Bay part of the Arctic or the Atlantic Ocean?" Tags="|oceanography|geography|watershed|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="19118" PostTypeId="2" ParentId="19101" CreationDate="2020-02-04T13:01:54.897" Score="5" Body="&lt;p&gt;&lt;a href=&quot;http://glossary.ametsoc.org/wiki/Cloud&quot; rel=&quot;nofollow noreferrer&quot;&gt;Clouds&lt;/a&gt; consist of suspended (floating) liquid water droplets (&quot;liquid clouds&quot;), frozen (solid) ice particles (&quot;ice clouds&quot;), or a mixture of both (&quot;mixed phase clouds&quot;).  In-between those droplets or ice particles (meteorologists use the phrase &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Hydrometeor&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;hydrometeor&lt;/em&gt;&lt;/a&gt; to encompass both) is air which will contain water vapour, but what you are seeing is the liquid and solid parts.  Some people believe that when they're seeing clouds, they're seeing water vapour.  They are wrong.  Don't feel bad about sharing this belief, I've known an atmospheric (!!) scientist at a national research institute have the same misconception.  Whether the humid air between the droplets or particles is part of the cloud is a matter of definition, but &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014JD022494&quot; rel=&quot;nofollow noreferrer&quot;&gt;ice particles may contain air bubbles&lt;/a&gt; so I think it would be unreasonable to say there is no water vapour in a cloud.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One way to tell this by yourself is experiencing fog.  &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Fog&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fog&lt;/a&gt; is nothing else than a cloud that is connected to the ground.  If you walk through fog (preferably dense fog) and look carefully, you will notice it consists of many tiny water droplets (or &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Ice_fog&quot; rel=&quot;nofollow noreferrer&quot;&gt;ice particles&lt;/a&gt;, but then it should be &lt;em&gt;very&lt;/em&gt; cold, as small cloud particles will not freeze immediately at -5°C or -10°C).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tall clouds such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Cumulonimbus_cloud&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cumulonimbus&lt;/a&gt; usually consist of liquid droplets near the bottom, ice particles in the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Incus&quot; rel=&quot;nofollow noreferrer&quot;&gt;anvil or incus&lt;/a&gt; (the top part that may spread out horizontally), and mixed in-between.  Mixed phase clouds are pretty difficult to model or even measure accurately, as the exact proportion between liquid and solid depends on many (unknown) factors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See also &lt;a href=&quot;http://www.cas.manchester.ac.uk/resactivities/cloudphysics/background/ice/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ice and Mixed Phase Clouds&lt;/a&gt; at the Centre for Atmospheric Science, University of Manchester (UK).&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2020-02-04T13:13:26.560" LastActivityDate="2020-02-04T13:13:26.560" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19119" PostTypeId="1" CreationDate="2020-02-04T13:26:22.160" Score="3" ViewCount="198" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4FbEd.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4FbEd.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The multi-brown &amp;quot;hand&amp;quot; at the middle of this image is the Verkhoyansk Mountain Range in northeastern Russia.  The best information I got regarding its age is simply &amp;quot;Cretaceous&amp;quot;.  But &lt;em&gt;&lt;strong&gt;when&lt;/strong&gt;&lt;/em&gt; in the Cretaceous?  Because that is a pretty extensive chapter in Earth's geological history, spanning from 145 to 66 million years ago.&lt;/p&gt;&#xA;" OwnerUserId="4985" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-02-24T05:44:06.517" Title="How Old Are the Verkhoyansk Mountains in Northeastern Russia?" Tags="|mountains|age|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19121" PostTypeId="2" ParentId="7584" CreationDate="2020-02-05T04:55:59.650" Score="1" Body="&lt;p&gt;I've been working, as a hobbyist, on an alternate method of solar sun shading feel I feel I can help answer this question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Technically, any project which affect the climate of a planet is a form of geoengineering. This includes the current GHG crisis as mentioned by jamessqf above. But reversing GHG emissions to return to preindustrial levels is also a form of geoengineering. Thus, no matter what we do (continue current trends or modify them) we will be performing geoengineering. The lesson from this is that life is a balance. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What most people think of as geoengineering is a large scale project designed to mitigate certain climate effects across a planetary scale. This includes things like releasing aerosolized particles into the air but also things like increasing seafoam or spraying salt/saltwater into the air over oceans to create small clouds that reflect sunlight.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Something else to consider is that often experiments are conducted specifically to fail. Rocket tests that destroy the rocket have been in the news because they wanted to make sure backups work as expected. Science works that way with geoengineering as well. They try to break things to understand how they break better. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some things else to consider is the effect on different biomes of different sizes. The world literally operates differently for life of different sizes such as a microbe compared to ants, and an ant compared to us. An ant can fall off the empire state building and be just fine and us, well, not so much. Some insects are so small they swim through the air rather than fly. Thus we have to keep all sizes of life in our consideration. Seafoam may cause certain bacteria to flourish and kill others and we might not know for years. This effect might not be that big or it could cause dangerous algae blooms (this is a theoretical example not backed by any experiment). This plays into your LHC example. LHC operates on the smallest units we can manipulate. The earth is the largest unit we can currently manipulate and the rules are very different. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Going back to your original questions and worst-case scenarios we could cause issues with the earth's ozone layer, collapsing it and wiping out humanity, we might cause massive storms, we might kill off keystone species (some of which might exist on a microscopic level making it hard to detect until it's too late) causing great dyings releasing more GHG into the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The most realistic issue is that we don't apply geoengineering evenlyish (I add ish because optimal applications won't actually be even. Studies have shown that adopting certain areas, or engaging only certain areas with geoengineering, will make negative effects of climate change worse in the least modified areas. This means that is the USA implements geoengineering and Africa doesn't Africa will have a harder time. Conversely, studies have also indicated that well-implimented geoengineering can reduce inequality between nations which would drastically boost the quality of life and economy of the world's population as a whole.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other than that the next most likely possibility is that geoengineering causes some large scale issues which will cause great dyings which will release more GHG into the atmosphere. Life is a giant cycle of carbon and other compounds and messing with that cycle causes levels of different chemicals and elements to change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I see the argument that once we start geoengineering we can't stop. This is assuming GHG  levels are maintained or increased (which is what we are going for) and suddenly removing a technology that lowers the temp by 0.5-2C would result in fast changes than would happen 'naturally'. However, this concern assumes that we only have 1-2 geoengineering projects to work with. A more realistic view is that we will use multiple methods in conjunction. Not only does this redundancy remove the concern that any single project can't be removed but it allows for some projects being better or safer in different circumstances. We will learn a lot, and it lowers the number of unintended side effects for any particular project. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope this helps.&#xA;-Tristan&lt;/p&gt;&#xA;" OwnerUserId="18851" LastActivityDate="2020-02-05T04:55:59.650" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19122" PostTypeId="2" ParentId="16392" CreationDate="2020-02-05T05:17:17.920" Score="2" Body="&lt;p&gt;Short Answer yes, there may be side effects. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Long answer. They are looking at more than just sulfates. Initial research has shown an optimistic lack of side effects for sulfates but we won't know until we actually test it and testing over a 1km area, something attempted multiple times, has been blocked for environmental concerns. Concerns exist because we can't test it because it's blocked for environmental concerns.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The thing to keep in mind is that the original idea was &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;proposed to shock the scientific community into researching multiple avenues by Lowell Wood in 1999 (I could not find the source but it was a Wikipedia article so take it as you will.) &lt;/li&gt;&#xA;&lt;li&gt;is based off the cooling effects of volcanoes. &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;The second point is the most important because we have a natural phenomenon to work off of. there was a volcanic eruption in the 90s that lowered global temperatures by ~1.5 degrees (I believe it was C) over 18 months before things returned to normal. This means we can study the effects of volcanoes and predict the effects of the aerosol injection. Side effects of volcanoes include large impacts on vegetation and cooling but little else is cited in the articles I've seen. Fortunately, they believe that aerosolized injection into the upper atmosphere will avoid affecting plants very much if at all as the particles will mostly stay up there. However, there is concern that it might modify our atmosphere in some unknown way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have seen some articles saying sulfur emissions in China/asia might actually already be helping lower global temperatures a little but the idea was theoretical and the articles mostly seemed like clickbait.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Really we aren't sure and need to do some testing to find out. However, this will be small scale testing that will ramp up slowly.&lt;/p&gt;&#xA;" OwnerUserId="18851" LastEditorUserId="6031" LastEditDate="2020-02-05T05:35:00.170" LastActivityDate="2020-02-05T05:35:00.170" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19123" PostTypeId="2" ParentId="12681" CreationDate="2020-02-05T05:27:26.323" Score="1" Body="&lt;p&gt;The crux of the research is that not spreading the love around will negatively affect regions that don't participate. As in the situation gets worse than it would otherwise because somewhere else it gets better. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As to what scientists thought before this, they probably mostly thought they had theories and needed more data to determine the best approach. Assumptions are what science is based on but it's the testing, exploration, evaluation, and accidents along the way that allow science to find best fits. The articles listed were an exploration of best-fit understanding. It also gives facts for people to point to when they need to call out bad ideas like only helping North America or focusing only on Africa. Also, people will often call out scientists for not knowing what they are doing when in reality the people making such accusations refuse to look at the research. This is the research the scientists look at to get a better picture and that some others may ignore because if it doesn't serve their interests.&lt;/p&gt;&#xA;" OwnerUserId="18851" LastEditorUserId="6031" LastEditDate="2020-02-05T05:33:52.360" LastActivityDate="2020-02-05T05:33:52.360" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19124" PostTypeId="1" AcceptedAnswerId="19240" CreationDate="2020-02-05T10:09:12.867" Score="7" ViewCount="225" Body="&lt;p&gt;I always saw the definitions of &quot;&lt;em&gt;hydro-meteorological hazards&lt;/em&gt;&quot; and &quot;&lt;em&gt;climate extremes&lt;/em&gt;&quot; as almost interchangeable in the climate change and natural hazards literature. The other day I was discussing with a colleague claiming that &quot;&lt;em&gt;climate extremes&lt;/em&gt;&quot; would be a sort of &lt;em&gt;subset&lt;/em&gt; of the natural hazards.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although, I can find reasonable that, somehow, not all the hazards are climate extremes, I still find formally acceptable to define the most common ones (floods, droughts, heat waves, storms ...) both as &lt;em&gt;climate extremes&lt;/em&gt; and &lt;em&gt;hydro-meteorological hazards&lt;/em&gt;. Articles in literature (as &lt;a href=&quot;https://science.sciencemag.org/content/289/5487/2068&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt;, for instance), and also the &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/11/sr15_glossary.pdf&quot; rel=&quot;noreferrer&quot;&gt;IPCC Glossary&lt;/a&gt; do not seem to make a clear distinction.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any specialist here that can help me to shed light on this?&lt;/p&gt;&#xA;" OwnerUserId="8087" LastActivityDate="2020-02-17T22:43:07.577" Title="Hydro-meteorological hazards vs climate extremes" Tags="|climate-change|terminology|extreme-weather|" AnswerCount="2" CommentCount="6" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19125" PostTypeId="1" CreationDate="2020-02-05T11:15:09.097" Score="4" ViewCount="578" Body="&lt;p&gt;I find it very surprising that metal ore deposits are so separate, and unevenly separated on the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do understand that there were various different conditions at some point in time in the places where ore deposits emerged, and the places were somewhat randomly distributed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But how is it that there so many different conditions happening that all have fundamentally different effects? I would expect many different conditions, that can be grouped in much fewer types regarding the practical effect of the condition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or is exactly that the case, and what is surprising is only the numbers involved?&lt;/p&gt;&#xA;" OwnerUserId="321" LastActivityDate="2020-02-07T22:35:33.927" Title="Why are metals so separated in the Earths crust?" Tags="|rocks|ore|" AnswerCount="2" CommentCount="3" ClosedDate="2020-02-25T11:39:55.853" ContentLicense="CC BY-SA 4.0" />
  <row Id="19126" PostTypeId="2" ParentId="19125" CreationDate="2020-02-05T13:19:07.600" Score="-3" Body="&lt;p&gt;When the Earth was formed and was still in a molten or semi-molten state, the heavy metals, principally iron and nickel, were attracted by gravity to the Earth's deep interior, leaving only traces of them on the surface. However, the bombardment by comets, asteroids and mega-meteorites continued after a crust was formed. These were of varied composition and dumped their cargoes of metals randomly across the globe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to this, volcanoes spewed metal-rich magma into the upper layers of the crust, again rather randomly, and hydro-thermal seepages brought up metals from the depths and deposited them in the rocks on or near the surface. Magma plumes originating far down in the mantle can carry various elements, including metals, up to the surface. It often happens that metals which are close to each other in the periodic table and have similar properties are deposited in the same place. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-02-05T13:19:07.600" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19127" PostTypeId="1" CreationDate="2020-02-05T16:54:05.020" Score="4" ViewCount="1193" Body="&lt;p&gt;I am finding lots of information about Earth's energy budget, about how objects emit infrared radiation based on heat, and lots of related things, but nothing helping me figure out how much energy is actually being emitted by the ground at night.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At night, the ground will still be emitting electromagnetic energy. The amount of energy being emitted will vary based on many factors. Information that helps with many different types of land in various conditions would be great, but for my case I'm focusing on a stereotypical grassy plain in an area which has been between 5C-40C (40F-100F) for the past weeks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ultimately I'd like to have a rough ballpark figure of watts per square meter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In response to @Michael's comment:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The amount of energy emitted by night depends on how much it receives during the day, water content, length and type of grass and other vegetation, how many &quot;past weeks&quot; have there been, and what was the temperature of the ground when the relevant period began.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;During a sunny day the ground is said to receive approximately 1 kilowatt per square meter.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assume grass of 10cm-50cm (about a half foot to a couple feet). There have been thousands of past weeks. Since we need to get picky let's say the temperature has been a constant 10C (50F) every hour of every night and 15C (60F) every hour of every day for the last thousand years except for the 1 or 2 hours day/night transition where the temperature adjusts linearly back and forth if that makes the exercise easier. And the average annual rainfall of this location is 100cm (40in), rain was coming regularly at that rate until 4 days ago. In the last 4 days, it has rained once, yesterday afternoon dropping about 1cm (half-inch), and the water table is generally about 5 feet under ground level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The dirt is completely covered and appears as you would expect if you Googled an image of a grassy meadow. For example, the picture I've added at the bottom of the question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In my opinion, however, the best answer would not just say &quot;The ground emits 10 watts per square meter under those exact conditions!&quot; (even that would be useful though) but would instead say &quot;The type of grass actually makes a significant difference that can throw off even a ballpark estimate, as the difference between grass type A and grass type B produces a whopping half-order-of-magnitude difference in final results due to the way their outer material insulates them! And the difference between wet grass and dry grass is actually 2 orders of magnitude! If I were to simply pick a random, reasonable scenario of ABC it would be within the order of magnitude of 0.1 to 1 watts per square meter, and that's on the high end.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For anything else that matters feel free to simply pick a reasonable value and mention (even if only in a few words) why it matters and if your pick produces a high, low, or mid-range estimate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4WZi6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4WZi6.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11171" LastEditorUserId="11171" LastEditDate="2020-02-05T18:03:22.427" LastActivityDate="2024-01-11T11:29:42.527" Title="How much energy does Earth surface radiate at night per square meter?" Tags="|energy-balance|" AnswerCount="1" CommentCount="18" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19129" PostTypeId="2" ParentId="18067" CreationDate="2020-02-05T19:04:45.913" Score="2" Body="&lt;p&gt;You can try the R package &lt;a href=&quot;https://atmoschem.github.io/eixport/&quot; rel=&quot;nofollow noreferrer&quot;&gt;eixport&lt;/a&gt;, with &lt;a href=&quot;https://atmoschem.github.io/eixport/reference/wrf_put.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;wrf_put&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;# example&#xA;# Read the array emissions,&#xA;CO &amp;lt;- wrf_get(file = &quot;Path_to_WRFCHEMI&quot;, name = &quot;E_CO&quot;)&#xA;# Change the values, here you should use your data&#xA;CO[] = rnorm(length(CO))&#xA;# Inyect your emissions into the wrfchemi&#xA;wrf_put(file = &quot;Path_to_WRFCHEMI&quot;, name = &quot;E_CO&quot;, POL = CO)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How to deal with the speciation (my shapefile has only PM10 and&#xA;  PM2.5). where exactly do I place this in the new emissions file (the&#xA;  edited wrfchemi)I want. There are many pm species there (like pm2.5&#xA;  nucleation mode, pm, etc). I am not sure what weights to put on these.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You need to know the speciation for your local. At my department at Uni. of São Paulo, we use the following speciation of PM 2.5 (g/h/km^2)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;e_so4i = 0.0077, e_so4j = 0.0623, e_no3i = 0.00247, e_no3j = 0.01053, e_pm2.5i = 0.1, e_pm2.5j = 0.3, e_orgi = 0.0304, e_orgj = 0.1296, e_eci = 0.056, e_ecj = 0.024, h2o = 0.277&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Check &lt;a href=&quot;https://atmoschem.github.io/vein/reference/speciate.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;My emissions are not time dependent, and what do I do when I edit the&#xA;  wrfchemi file for this. (the wrfchemi files I have now are also not&#xA;  time dependent)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You need to first edit the namelist.wps and namelist.input to the desired length of time. Then, after running  ./real.exe you will have the wrfinput_d0x. At this stage you can use &lt;a href=&quot;https://atmoschem.github.io/eixport/reference/wrf_create.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;wrf_create&lt;/a&gt; which creates a wrfchemi file with 0. Read the manual to see if you want two 0-12z 12-0z files or one file with the length for all hours. Then you can use wrf_put. Just follow the example and read the manual.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might also try the R package &lt;a href=&quot;https://atmoschem.github.io/EmissV/&quot; rel=&quot;nofollow noreferrer&quot;&gt;EmissV&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;References&lt;/em&gt;:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Ibarra-Espinosa et al., (2018). eixport: An R package to export&#xA;emissions to atmospheric models. Journal of Open Source Software,&#xA;3(24), 607, &lt;a href=&quot;https://doi.org/10.21105/joss.00607&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.21105/joss.00607&lt;/a&gt; Schuch et al.,&#xA;(2018). &lt;/li&gt;&#xA;&lt;li&gt;EmissV: an R package to create vehicular and other emissions&#xA;for air quality models. Journal of Open Source Software, 3(30), 662,&#xA;&lt;a href=&quot;https://doi.org/10.21105/joss.00662&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.21105/joss.00662&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="6489" LastEditorUserId="6489" LastEditDate="2020-02-06T14:32:44.640" LastActivityDate="2020-02-06T14:32:44.640" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19131" PostTypeId="1" CreationDate="2020-02-05T21:34:26.547" Score="2" ViewCount="137" Body="&lt;p&gt;I have seen ample consensus amongst reputable scientists that the earth is getting warmer, and this fact is due to human activity (e.g &lt;a href=&quot;https://climate.nasa.gov/faq/17/do-scientists-agree-on-climate-change/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://climate.nasa.gov/faq/17/do-scientists-agree-on-climate-change/&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The affirmation &quot;97 percent of the scientists with the relevant expertise agree that climate change is real and caused by humans&quot;, in particular, gets a lot or airtime.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have not yet, however, seen similar consensus for the effects of climate change. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a large, documented consensus on any estimate of sea level raise or any other more &quot;direct&quot; effect on the human population?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Variation is not a problem, as long as a significant percentage of scientists/papers affirm at least X of variation of sea level, and X is enough to be a big problem&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Or the analogous affirmation for a different climate change effect)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To be more concrete, is there a survey of scientists or a meta analysis paper that mentions a significant effect, that would affect how humans live, and that shows 90% or more of agreement (of the relevant papers or the relevant scientists)?&lt;/p&gt;&#xA;" OwnerUserId="18856" LastEditorUserId="18856" LastEditDate="2020-02-06T12:12:50.003" LastActivityDate="2020-02-06T12:57:32.883" Title="What are the affirmations regarding the effects of climate change that have a high degree of consensus amongst climate scientists?" Tags="|climate-change|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="19132" PostTypeId="1" CreationDate="2020-02-06T02:02:55.663" Score="3" ViewCount="141" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/CHEOPS&quot; rel=&quot;nofollow noreferrer&quot;&gt;CHEOPS&lt;/a&gt; (also &lt;a href=&quot;https://www.cosmos.esa.int/web/cheops/cheops-launch-and-operations&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;https://youtu.be/EAIUJaaVJ9U&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;, 3) is a space telescope recently put in low Earth orbit to look for exoplanets around other stars. It uses a cooled detector array and so uses a heat shield to avoid thermal radiation from the Sun as well as the Earth directly below. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thermal radiation from the Earth is a significant problem for spacecraft thermal management in low Earth orbit, so it's important to know how much thermal radiation Earth emits into space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we use &lt;a href=&quot;https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA18833&quot; rel=&quot;nofollow noreferrer&quot;&gt;an average emissivity &lt;span class=&quot;math-container&quot;&gt;$\epsilon$&lt;/span&gt; of 0.8&lt;/a&gt; and assume a temperature of 0 °C, then using&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$P= \sigma \epsilon T^4$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where the &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_constant&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stefan-Boltzmann constant&lt;/a&gt; &lt;span class=&quot;math-container&quot;&gt;$\sigma$&lt;/span&gt; is 5.67 &lt;span class=&quot;math-container&quot;&gt;$\times 10^{-8}$&lt;/span&gt; W m&lt;sup&gt;-2&lt;/sup&gt; K&lt;sup&gt;-4&lt;/sup&gt; we can estimate it to be about 250 W/m&lt;sup&gt;2&lt;/sup&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But what is it really, and how does it vary (on average) by the type of terrain under a satellite and time of day? &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;https://space.stackexchange.com/a/40557/12102&quot;&gt;this answer&lt;/a&gt; to &lt;em&gt;For a given 48 hour observing period, what fraction of the celestial sphere is available to CHEOPS?&lt;/em&gt; (originally from &lt;a href=&quot;https://sci.esa.int/documents/34375/36249/1567259940843-CHEOPS_EST_SCI_RP_001_RedBook_i1.0.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;the CHEOPS Red Book ESA/SRE(2013)7&#xA;November 2013&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Z5bQI.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Z5bQI.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2020-02-06T08:55:21.797" Title="How does Earth's thermal radiation into space vary by location and time of day?" Tags="|atmospheric-radiation|radiative-transfer|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19133" PostTypeId="1" CreationDate="2020-02-06T04:50:57.077" Score="5" ViewCount="153" Body="&lt;p&gt;Need temperature for 24 hours for each county of United States. Average values is ok, seasonal granularity welcome. I've been looking at nClimDiv datasets &lt;/p&gt;&#xA;" OwnerUserId="18858" LastActivityDate="2020-02-06T20:17:32.083" Title="Where can I get hourly ambient temperature for each county in United States?" Tags="|climate|climate-models|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19134" PostTypeId="1" AcceptedAnswerId="19135" CreationDate="2020-02-06T05:55:02.093" Score="36" ViewCount="15772" Body="&lt;p&gt;Or does the mantle and crust above you counteract the increase at one point and it actually decreases?&lt;/p&gt;&#xA;" OwnerUserId="18859" LastEditorDisplayName="user20559" LastEditDate="2021-05-11T09:45:18.397" LastActivityDate="2021-05-11T09:45:18.397" Title="Does gravity increase the closer to the core you get?" Tags="|geology|geophysics|earth-observation|gravity|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19135" PostTypeId="2" ParentId="19134" CreationDate="2020-02-06T08:23:04.990" Score="54" Body="&lt;p&gt;The below figure, taken from &lt;a href=&quot;https://en.wikipedia.org/wiki/Gravity_of_Earth&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt; shows a model of the free fall acceleration, i.e., 'gravity'. The left-most point corresponds to the center of the Earth; then further right at &lt;span class=&quot;math-container&quot;&gt;$6.3\cdot1000$&lt;/span&gt; km you are at the Earth's surface; and then further out you move into space. You can follow the blue line for &lt;a href=&quot;http://en.wikipedia.org/wiki/Preliminary_reference_Earth_model&quot; rel=&quot;noreferrer&quot;&gt;PREM&lt;/a&gt; to get an idea of the average (expected) gravity. As you see, the gravity actually increases slightly within the Earth (reaching a maximum at the core-mantle boundary), but tapers down within the core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To make this kind of calculations, you must think of the Earth like an onion: made up of many concentric spheres. Whenever you move a bit deeper into the Earth, you strip off all the layers you've crossed. As you get closer to the center of the Earth, there are fewer and fewer layers, and eventually, there's nothing left at the center! The reason why gravity goes up ever so slightly within the Earth is that you get close to the much denser core material. If the density of the Earth were constant (per the green 'constant density' line), the gravity would just decrease linearly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Zz4VN.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Zz4VN.png&quot; alt=&quot;Gravity acceleration of Earth&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See &lt;a href=&quot;https://earthscience.stackexchange.com/a/19140/12155&quot;&gt;the other answer&lt;/a&gt; and the discussion below for some more details on the math and procedures required to make these calculations.&lt;/p&gt;&#xA;" OwnerUserId="12155" LastEditorUserId="12155" LastEditDate="2020-02-08T20:24:57.110" LastActivityDate="2020-02-08T20:24:57.110" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="19136" PostTypeId="2" ParentId="19132" CreationDate="2020-02-06T08:55:21.797" Score="2" Body="&lt;p&gt;The yearly average Top Of Atmosphere (TOA) Outgoing Longwave Radiation (OLR) is around 145–345 W/m², as measured by the AIRS instrument:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/e/e0/AIRS_OLR.png/1024px-AIRS_OLR.png&quot; alt=&quot;OLR&quot; title=&quot;Outgoing longwave radiation&quot;&gt;&lt;br&gt;&#xA;&lt;sup&gt;&lt;em&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/w/index.php?title=File:AIRS_OLR.png&amp;amp;oldid=213002906&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikimedia Commons contributors, &quot;File:AIRS OLR.png,&quot; Wikimedia Commons, the free media repository&lt;/a&gt;&lt;/em&gt;. &lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, this is an average that includes both day and night.  How much does it vary?  This depends on the location.  Based on GERB data, a 2007 paper estimates (please pay attention to the thick solid line only):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sZgjx.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sZgjx.png&quot; alt=&quot;OLR diurnal cycle&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;em&gt;Source: Comer, Slingo, and Allan (2007)&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even in places with a very large diurnal temperature cycle such as the Sahara, the difference between maximum and minimum is only about 10%.  In oceanic areas it is closer to 2%.  That means that if you take the mean (shown in the top figure) and subtract around 1–5% depending on the region (the drier, the more difference) you get a reasonable estimate of the nighttime outgoing longwave radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want a more precise estimate, you can always download satellite data and calculate it yourself.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Full source for second figure: Comer, Slingo, and Allan (2007), Observations of the diurnal cycle of outgoing longwave radiation from the Geostationary Earth Radiation Budget instrument, Geophysical Research Letters, Vol. 34, L02823, doi:10.1029/2006GL028229&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2020-02-06T08:55:21.797" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19137" PostTypeId="2" ParentId="19133" CreationDate="2020-02-06T09:25:33.423" Score="7" Body="&lt;p&gt;You can get this from the &lt;a href=&quot;https://www.ncdc.noaa.gov/isd&quot; rel=&quot;nofollow noreferrer&quot;&gt;Integrated Surface Dataset (ISD)&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First get a list of all weather stations from &lt;code&gt;ftp://ftp.ncdc.noaa.gov/pub/data/noaa/isd-history.txt&lt;/code&gt;:&lt;/p&gt;&#xA;&#xA;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;stations = pandas.read_fwf(&quot;ftp://ftp.ncdc.noaa.gov/pub/data/noaa/isd-history.txt&quot;, &#xA;                           skiprows=20, parse_dates=[&quot;BEGIN&quot;, &quot;END&quot;],&#xA;                           skip_blank_lines=True,&#xA;                           dtype={&quot;WBAN&quot;: &quot;O&quot;})&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Then select the ones in the USA:&lt;/p&gt;&#xA;&#xA;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;stations_us = stations[stations[&quot;CTRY&quot;]==&quot;US&quot;]&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;That give us 7326 stations.  Although the state of each station is described, the county is not.  To get the county you will need to combine the lat/lon for each station with a county database.  That is a bit beyond the scope of Earth Science SE, but maybe you can get help at &lt;a href=&quot;https://gis.stackexchange.com&quot;&gt;GIS&lt;/a&gt; SE.  The station ID is a combination of two fields:&lt;/p&gt;&#xA;&#xA;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;ids = stations_us[&quot;USAF&quot;] + stations_us[&quot;WBAN&quot;]&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;We can then download the measurements for a particular year from AWS S3:&lt;/p&gt;&#xA;&#xA;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;meas = pandas.read_csv(f&quot;s3://noaa-global-hourly-pds/2020/{ids.iloc[200]:s}.csv&quot;, parse_dates=[&quot;DATE&quot;])&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;And extract temperatures:&lt;/p&gt;&#xA;&#xA;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;temps = meas.TMP.str.extract(r&quot;([+-]\d{4}),([012345679ACIMPRU])&quot;)[0].astype(&quot;f4&quot;)/10&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Let's get the valid ones (there's a 9999 fill value) and plot:&lt;/p&gt;&#xA;&#xA;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;valid = temps&amp;lt;999&#xA;meas[valid].set_index(meas.DATE[valid])[&quot;temps&quot;].plot()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LEn8G.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LEn8G.png&quot; alt=&quot;measurements&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Enjoy!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a description of the fields, see the ISD Format Document at &lt;a href=&quot;https://www.ncei.noaa.gov/data/global-hourly/doc/isd-format-document.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncei.noaa.gov/data/global-hourly/doc/isd-format-document.pdf&lt;/a&gt; .&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2020-02-06T20:17:32.083" LastActivityDate="2020-02-06T20:17:32.083" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19138" PostTypeId="2" ParentId="18858" CreationDate="2020-02-06T09:34:56.273" Score="1" Body="&lt;p&gt;I too don't know any direct sources.  So you will likely have to do a bit of legwork.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Was going to offer that you could work a climatology together from&#xA;monthly FP6 reports using the desired NWS site (click the office on&#xA;&lt;a href=&quot;https://sercc.com/nowdata.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://sercc.com/nowdata.html&lt;/a&gt;, then switch to observed weather, then&#xA;select CF6 and choose the site and then indicate the month report you&#xA;want... on those reports any date with a 3 in the WX column had&#xA;thunder... then you could sum them over many reports to make a&#xA;climatology... time consuming, but I've done similar.  It would be&#xA;feasible to do a few sites, but brutal to do for many without&#xA;automating the process)&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;But it looks like Iowa State's IEM ADP comes through with something a&#xA;bit more robust and more reasonable in the amount of work it takes to&#xA;finish together...   Using option &lt;a href=&quot;https://mesonet.agron.iastate.edu/plotting/auto/?q=87&quot; rel=&quot;nofollow noreferrer&quot;&gt;ADP #87 here&lt;/a&gt;, select the &#xA;state/country of interest, then city you want data on (you may wish to further&#xA;look into what the official observing site is for the city you want)... make&#xA;sure you have thunder as the code choice, and select group by day of&#xA;the years.  Choose your years {you may want to skip the first and&#xA;current year for better hopes of about equal data sets for each day&#xA;of the year... you also may want to avoid going back too far in time,&#xA;as it looks like records may have been less complete back towards the&#xA;1950s and earlier}, then make the plot with options.   It'll produce&#xA;a nice graphic which you may find useful.  If you want precise&#xA;numbers, you can reasonably make the true climatology by clicking&#xA;download as Excel below the plot.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(If anyone reading happens to be a little unfamiliar with Excel {Open Office likely would work fairly similar?}... I can try to run you through the remaining process I used for this graphic:&lt;br&gt;&#xA;&lt;a href=&quot;https://excel.officetuts.net/en/examples/select-multiple-columns-in-excel&quot; rel=&quot;nofollow noreferrer&quot;&gt;select the day and year columns together&lt;/a&gt;,&lt;br&gt;&#xA;then &lt;a href=&quot;https://stackoverflow.com/questions/30501104/removing-duplicates-in-excel&quot;&gt;filter out duplicates&lt;/a&gt;,&lt;br&gt;&#xA;then &lt;a href=&quot;https://support.office.com/en-us/article/count-how-often-a-value-occurs-aa1f3067-05c9-44e4-b141-f75bb9bb89bd&quot; rel=&quot;nofollow noreferrer&quot;&gt;make a Pivot Table&lt;/a&gt; in a new sheet with doy as Row Label&#xA;and count of year as Σ values.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pnlRh.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;After one mistake in reading&lt;/a&gt;, I realized you wanted monthly data... from here there may be &lt;a href=&quot;https://support.office.com/en-us/article/group-or-ungroup-data-in-a-pivottable-c9d1ddd0-6580-47d1-82bc-c84a5a340725&quot; rel=&quot;nofollow noreferrer&quot;&gt;easier ways to do the rest&lt;/a&gt;, but using my old Office 2007 and somewhat limited skill, I pushed through to get all dates summed by writing the formula &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;=ROW()-3  &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;in cell D4 and&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;=IFERROR(GETPIVOTDATA(&quot;year&quot;,\$A$3,&quot;doy&quot;,ROW()-3),0)  &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;in cell E4.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then expanded those cell formulas downward to row 369 (so 366 days were covered).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then I typed the month names in F4-F15 and the formulas&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;=SUM(E4:E34)/50&lt;br&gt;&#xA;  =SUM(E35:E63)/50&lt;br&gt;&#xA;  =SUM(E64:E94)/50&lt;br&gt;&#xA;  =SUM(E95:E124)/50&lt;br&gt;&#xA;  =SUM(E125:E155)/50&lt;br&gt;&#xA;  =SUM(E156:E185)/50&lt;br&gt;&#xA;  =SUM(E186:E216)/50&lt;br&gt;&#xA;  =SUM(E217:E247)/50&lt;br&gt;&#xA;  =SUM(E248:E277)/50&lt;br&gt;&#xA;  =SUM(E278:E308)/50&lt;br&gt;&#xA;  =SUM(E309:E338)/50&lt;br&gt;&#xA;  =SUM(E339:E369)/50  &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;in G4-G15.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Select the F and G columns, add a bar graph from that, add a title, and I had:&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/K6QbC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/K6QbC.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's certainly not readymade :-(&lt;br&gt;&#xA;But it does at least seem a way you could possibly produce enough climatologies in reasonable time to get a rough idea of the country (or other parts of the world?)?&lt;br&gt;&#xA;Hope you/others can find something that is already completed, but if not, hopefully this offers something a bit useful.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Those looking to go all-out nuts and make a full dataset could download full ASOS data from &lt;a href=&quot;https://mesonet.agron.iastate.edu/request/download.phtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iowa State&lt;/a&gt; or &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/land-based-station-data/land-based-datasets/automated-surface-observing-system-asos&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCDC&lt;/a&gt; and put together a detailed script to pull out the pieces needed.  Feel free to share the data here if you do!)&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2020-02-06T09:34:56.273" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19139" PostTypeId="1" CreationDate="2020-02-06T10:24:31.440" Score="8" ViewCount="341" Body="&lt;p&gt;I am trying to understand the calculation of the wind speeds at forest edge. I am pretty new in wind simulation and profiles in general, so I am sorry if asking simple questions.&lt;/p&gt;&#xA;&lt;p&gt;I have found that it is possible to calculate the wind speed  as &lt;a href=&quot;https://en.wikipedia.org/wiki/Log_wind_profile&quot; rel=&quot;nofollow noreferrer&quot;&gt;log wind profile&lt;/a&gt; based on friction velocity, roughness length (&lt;span class=&quot;math-container&quot;&gt;${z0}$&lt;/span&gt;), zero place displacement (&lt;span class=&quot;math-container&quot;&gt;${d}$&lt;/span&gt;), and von Karman's constant (&lt;span class=&quot;math-container&quot;&gt;${k}$&lt;/span&gt;). As I am working at forest edge, my estimates are:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;z0 =  0.06          # m, roughness length, 1/10 of the surface roughness, forest:0.5-1m&#xA;d =   h/3*2         # m, zero place displacement, height (m) above the ground with 0 wind speed (2/3 or 3/4 of average height of obstacles) &#xA;k =   0.41      # no unit, von Karman constant  &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Formula:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;# predict speeds for individual segments of the tree&#xA;u_z = frict_velocity/k*log((z-d)/z0)   &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;However, it seems that friction velocity is not a constant, and needs to be calculated based on the wind speed measured at two heights. Well, I don't have two heights. The highest estimation I can get is that wind speed above canopy is &lt;span class=&quot;math-container&quot;&gt;${12ms^{-1}}$&lt;/span&gt; and at the height &lt;span class=&quot;math-container&quot;&gt;${d}$&lt;/span&gt; is 0, as estimated above. The formula is specified as &lt;a href=&quot;https://en.wikipedia.org/wiki/Shear_velocity&quot; rel=&quot;nofollow noreferrer&quot;&gt;shear velocity&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;u_canopy = 12  # speed on canopy top&#xA;u_d = 0        # speed on height d, which is 0&#xA;z_canopy = 25  # height of the canopy, equals tree height&#xA;z_d = d        # height of the wind speed 0, equals to d&#xA;&#xA;frict_velocity = k*(u_canopy - u_d)/log((z_canopy - d)/(z_d - d))   &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Well, this approach obviously predict just values higher than &lt;span class=&quot;math-container&quot;&gt;${d}$&lt;/span&gt;, even if all tree segments should have 0 value instead.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Bo1M9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Bo1M9.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Is my prediction of the wind speed on every segment &lt;span class=&quot;math-container&quot;&gt;${z}$&lt;/span&gt; right? Or, is there a way how to simply use the &amp;quot;friction velocity&amp;quot; constant, as I don't have wind speed estimation at two vertical heights?&lt;/p&gt;&#xA;&lt;p&gt;My goal is to predict wind speed on every segment (&lt;span class=&quot;math-container&quot;&gt;${z}$&lt;/span&gt;) and convert it to wind force to uproot the tree. The models should be included within a simulation study, so instead of specific single tree condition I am hoping to get some more general relationships.&lt;/p&gt;&#xA;" OwnerUserId="5907" LastEditorUserId="10735" LastEditDate="2021-09-18T03:57:02.800" LastActivityDate="2023-07-04T18:19:28.697" Title="Predict wind speed in a forest based on speed over and under canopy?" Tags="|atmosphere|wind|forest|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19140" PostTypeId="2" ParentId="19134" CreationDate="2020-02-06T10:55:43.253" Score="22" Body="&lt;p&gt;This is a companion to the &lt;a href=&quot;https://earthscience.stackexchange.com/a/19135/18801&quot;&gt;other answer&lt;/a&gt;.  The other answer gives values for what the acceleration actually &lt;em&gt;is&lt;/em&gt; based on knowledge about the composition of the planet.  In this answer I want to introduce some of the mathematical tools that allow you to reason about how gravity varies in and around planets.  &lt;a href=&quot;https://earthscience.stackexchange.com/a/19165/18801&quot;&gt;David Hammen's answer&lt;/a&gt;, which I think he wrote overlapping with the second part of this one, also has versions of some of the maths in the second part of this one, and is very worth reading.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;An idealised (and incorrect) Earth&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;First of all consider an idealised Earth: in this model Earth let's assume that the planet is:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;spherical;&lt;/li&gt;&#xA;&lt;li&gt;not spinning;&lt;/li&gt;&#xA;&lt;li&gt;has constant density throughout.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The first two of these are reasonably good approximations. the third is &lt;em&gt;not&lt;/em&gt; a good approximation: the density of the Earth in fact varies significantly with depth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For this simplified model we can use a famous result, proved by Newton, known as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Shell_theorem&quot; rel=&quot;nofollow noreferrer&quot;&gt;shell theorem&lt;/a&gt;.  This says two things:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;a spherically-symmetric mass distribution can be treated gravitationally outside it as if it was the same mass concentrated at a point at the centre of the sphere;&lt;/li&gt;&#xA;&lt;li&gt;a spherically-symmetric &lt;em&gt;shell&lt;/em&gt; of mass (so a hollow sphere) has &lt;em&gt;no&lt;/em&gt; gravitational influence on any body &lt;em&gt;inside&lt;/em&gt; the shell.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;From this it immediately follows that, at any point &lt;em&gt;inside&lt;/em&gt; our model Earth, you can ignore all the mass &lt;em&gt;outside&lt;/em&gt; that point and then just consider the gravitational influence of the mass &lt;em&gt;inside&lt;/em&gt; the point, and we can also consider that mass to be concentrated at the centre of the model Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, well, let the density of the planet be &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt;.  Then the mass within a radius &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; is &lt;span class=&quot;math-container&quot;&gt;$m(r) = 4\pi r^3 \rho/3$&lt;/span&gt;, for &lt;span class=&quot;math-container&quot;&gt;$r\le R_E$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$R_E$&lt;/span&gt; is the radius of the Earth.  And using Newton's law of gravitation, we get the acceleration due to gravity, &lt;span class=&quot;math-container&quot;&gt;$g(r)$&lt;/span&gt; to be&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\begin{aligned}&#xA;g(r) &amp;amp;= \frac{Gm(r)}{r^2}\\&#xA;     &amp;amp;=\frac{4\pi G\rho r}{3}\quad r \le R_E&#xA;\end{aligned}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which shows you that &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; reduces linearly as you approach the centre of the Earth in this model.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;A more realistic model Earth&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;A nice thing is that you can use most of the above even if &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; is not constant: so long as &lt;span class=&quot;math-container&quot;&gt;$\rho = \rho(r)$&lt;/span&gt;, only, then you can still use the shell theorem to compute &lt;span class=&quot;math-container&quot;&gt;$g(r)$&lt;/span&gt;, but you now have to do some integral over &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; to compute &lt;span class=&quot;math-container&quot;&gt;$m(r)$&lt;/span&gt;.  So you can relax the third requirement above, at the cost of a little more work.  I believe that, in practice, &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; does depend only on &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; to a fairly good approximation, so this model will let us compute how gravity actually does vary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the case where &lt;span class=&quot;math-container&quot;&gt;$\rho = \rho(r)$&lt;/span&gt; we can use the shell theorem to write &lt;span class=&quot;math-container&quot;&gt;$g(R)$&lt;/span&gt; at some radius &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; (I'm using &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; not because I want to integrate over &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\begin{aligned}&#xA;g(R) &amp;amp;= \frac{G m(R)}{R^2}\\&#xA;     &amp;amp;= \frac{G}{R^2}\int_0^R 4\pi r^2 \rho(r)\,dr&#xA;\end{aligned}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where the integral is the mass of the planet to radius &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt;.  It's clear from this that &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; is constant if &lt;span class=&quot;math-container&quot;&gt;$\rho(r) = \rho_0/r$&lt;/span&gt;: a planet with a density which goes down as &lt;span class=&quot;math-container&quot;&gt;$1/r$&lt;/span&gt; has gravitational acceleration which is constant throughout its volume.  Note that this planet has infinite density at its centre: since that's never true for planets – we're not dealing with black holes here, and if we were we could not use Newtonian gravitation – this means that for all real planets, &lt;span class=&quot;math-container&quot;&gt;$g \to 0$&lt;/span&gt; as &lt;span class=&quot;math-container&quot;&gt;$r \to 0$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More generally we can differentiate the above to get an expression for &lt;span class=&quot;math-container&quot;&gt;$dg/dR$&lt;/span&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{dg}{dR} = 4\pi G\rho(R)&#xA; - \frac{2G}{R^2}\int_0^R 4\pi R^2\rho(r)\,dr&#xA;$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Defining &lt;span class=&quot;math-container&quot;&gt;$\bar{\rho}(R)$&lt;/span&gt; as the mean density of the planet to radius &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt;, then the integral in the second term is just &lt;span class=&quot;math-container&quot;&gt;$4\pi R^3\bar{\rho}(R)/3$&lt;/span&gt;, so we get&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{dg}{dR} = 4\pi G\left(\rho(R) - \frac{2}{3}\bar{\rho}(R)\right)$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This tells you how &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; behaves with depth, and in particular whether it goes up or down with depth for a general spherically-symmetric mass distribution, if you know the radius, the density at that radius, and the mean density inside that radius (or equivalently the radius, the density, and the mass inside that radius).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, if we can measure how the density of Earth varies with depth, and that it varies &lt;em&gt;only&lt;/em&gt; with depth to a good approximation, then this model can be used to compute how &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; varies with depth, to a good approximation.&lt;/p&gt;&#xA;" OwnerDisplayName="user18801" LastEditorDisplayName="user18801" LastEditDate="2020-02-12T11:11:35.427" LastActivityDate="2020-02-12T11:11:35.427" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="19141" PostTypeId="2" ParentId="19131" CreationDate="2020-02-06T12:57:32.883" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is there a large, documented consensus on any estimate of sea level&#xA;  raise or any other more &quot;direct&quot; effect on the human population?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As Will said in a comment, IPCC has some estimates on that matter, although they vary depending on which emission scenario you choose. From the technical summary of the &lt;a href=&quot;https://www.ipcc.ch/srocc/chapter/technical-summary/ts-4sea-level-rise-and-implications-for-low-lying-islands-coasts-and-communities/&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC Special Report on Ocean and Cryosphere in a Changing Climate&lt;/a&gt;, section &quot;Projections&quot;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Future rise in GMSL [global mean sea level] caused by thermal expansion, melting of glaciers and ice sheets and land water storage changes, is strongly dependent on which Representative Concentration Pathway (RCP) emission scenario is followed. SLR [sea level rise] at the end of the century is projected to be faster under all scenarios, including those compatible with achieving the long-term temperature goal set out in the Paris Agreement. GMSL will rise between 0.43 m (0.29–0.59 m, likely range; RCP2.6) and 0.84 m (0.61–1.10 m, likely range; RCP8.5) by 2100 (medium confidence) relative to 1986–2005.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As for the meaning of this sea level rise on human population, it's better to look at the &lt;a href=&quot;https://www.ipcc.ch/srocc/chapter/summary-for-policymakers/spm-section-3/&quot; rel=&quot;nofollow noreferrer&quot;&gt;summary for policymakers of the same report&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The increasing frequency of high water levels can have severe impacts&#xA;  in many locations depending on exposure (high confidence). [...] Extreme sea levels and&#xA;  coastal hazards will be exacerbated by projected increases in tropical&#xA;  cyclone intensity and precipitation (high confidence). Projected&#xA;  changes in waves and tides vary locally in whether they amplify or&#xA;  ameliorate these hazards (medium confidence).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;On a more &quot;philosophical&quot; note, it is really difficult to predict the effect on humans because of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Self-defeating_prophecy&quot; rel=&quot;nofollow noreferrer&quot;&gt;prophet's dilemma&lt;/a&gt;. If we know bad things are going to happen, we will (or at least we should...) take measures to prevent them. Then the predicted things will not happen, making the prediction seem wrong, even if it was right at the time it was made! So we can predict that the sea level will rise (it will, no question about that), but we cannot predict the effect this rise will have on humans, because they will likely adapt to it before the effect happens.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-02-06T12:57:32.883" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19143" PostTypeId="1" CreationDate="2020-02-07T08:42:21.937" Score="5" ViewCount="160" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Stromatolite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stromatolites&lt;/a&gt; and other organisms have been storing &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; in the form of &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CaCO_3}$&lt;/span&gt; throughout the geological ages, forming extensive limestone deposits scattered across Earth's crust.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Has this &lt;span class=&quot;math-container&quot;&gt;$\small\sf{CO_2}$&lt;/span&gt; fixation process reduced significantly atmosphere mass? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or, as part of a biological cycle, it hasn't changed the quantity of molecules of Earth's atmosphere and has only changed atmosphere composition?&lt;/p&gt;&#xA;" OwnerDisplayName="user18590" LastEditorUserId="18081" LastEditDate="2020-02-07T11:36:26.950" LastActivityDate="2020-02-07T11:36:26.950" Title="Has Earth's atmosphere lost mass throughout the geological ages due to biological $\small\sf{CO_2}$ fixation?" Tags="|atmosphere|geochemistry|earth-history|biogeochemistry|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19144" PostTypeId="2" ParentId="19143" CreationDate="2020-02-07T10:00:12.673" Score="-1" Body="&lt;p&gt;Yes, the Earth's atmosphere has thinned in the past few billion years, and biological fixation of CO2 was one of the main causes. It also gave us our present abundance of oxygen (21%). Enormous quantities of CO2 were used in the form of CaCO3 by foraminifera, corals etc to make their hard skeletons, and the resulting sediments formed limestone. Other elements formed compounds with carbonic acid (CO2 + H2O) to create other carbonate rocks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition there is the more obvious sequestration of CO2 which was taken from the atmosphere by photosynthetic organisms and buried underground in the form of fossil hydrocarbons (oil, coal, gas, lignite etc). It was this which gave us our all-important oxygen. So the answer to your question is that biological activity has done both. It has hugely reduced the mass of the Earth's atmosphere, and at the same time greatly altered its composition.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is also worth noting that the Earth loses substantial quantities of atmospheric gases into space, mostly hydrogen, but other gases as well. The bombardment of the outer atmosphere by ultraviolet rays, cosmic rays and the solar wind plays a part in this.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-02-07T10:00:12.673" CommentCount="15" ContentLicense="CC BY-SA 4.0" />
  <row Id="19145" PostTypeId="1" AcceptedAnswerId="19148" CreationDate="2020-02-07T16:51:21.033" Score="4" ViewCount="299" Body="&lt;p&gt;Today, the Argentinian meteorological service tweeted about a new temperature record for Antarctica of 18.3°C, made on the Espezanza peninsula. This was subsequently reported by many other sources.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://twitter.com/SMN_Argentina/status/1225455484259442691&quot; rel=&quot;nofollow noreferrer&quot;&gt;twitter.com&lt;/a&gt;&#xA;&lt;a href=&quot;https://public.wmo.int/en/media/news/new-record-antarctic-continent-reported&quot; rel=&quot;nofollow noreferrer&quot;&gt;wmo.int&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.bloomberg.com/news/articles/2020-02-07/it-s-t-shirt-weather-in-antarctica-as-temperature-breaks-record&quot; rel=&quot;nofollow noreferrer&quot;&gt;bloomberg.com&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.nytimes.com/aponline/2020/02/07/world/europe/ap-eu-switzerland-un-antarctica.html?searchResultPosition=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;nytimes.com&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.theguardian.com/world/2020/feb/07/antarctica-logs-hottest-temperature-on-record-with-a-reading-of-183c&quot; rel=&quot;nofollow noreferrer&quot;&gt;theguardian.com&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The tweet contained an image of a literal analogue thermometer which did show the 18.3°C... but curiously enough, also &lt;em&gt;another&lt;/em&gt; thermometer showing merely 10.0°C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7XnXh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7XnXh.jpg&quot; alt=&quot;The image tweeted by SMN Argentina&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What's that about? Is that 10°C another means of measuring temperature, e.g. some kind of running average temperature? Or is one of the readings simply faulty?&lt;/p&gt;&#xA;" OwnerUserId="12095" LastActivityDate="2020-02-10T19:37:48.643" Title="What is the second thermometer in the image from the Esperanza Antarctic temperature record?" Tags="|meteorology|climate-change|temperature|measurements|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19146" PostTypeId="1" CreationDate="2020-02-07T17:28:47.037" Score="5" ViewCount="214" Body="&lt;p&gt;The rigid mantle, which is hard and lies above the asthenosphere, is separated from the &quot;crust&quot; that we can see and touch by the Mohorovičić discontinuity. Wikipedia &lt;a href=&quot;https://en.wikipedia.org/wiki/Mohorovi%C4%8Di%C4%87_discontinuity&quot; rel=&quot;noreferrer&quot;&gt;provides&lt;/a&gt; an image of what may once have been part of the discontinuity, but I haven't been able to find a good source on what the actual rigid mantle looks like.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do we know what the rigid mantle itself looks like or how it would look to the naked eye? That is, if I could somehow use my Unobtainium 9000 SuperDrill to drill down to the mantle and excavate a 1 meter squared cube of rigid mantle, what would it actually look like once I got it up to the surface? Would it just look like a slab of random silicates like as could be found in some mine today? Would it look distinctly &quot;alien&quot;?&lt;/p&gt;&#xA;" OwnerUserId="11158" LastActivityDate="2020-02-10T12:39:05.747" Title="Do we know what the rigid mantle looks like?" Tags="|geology|mantle|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19147" PostTypeId="1" CreationDate="2020-02-07T18:09:45.530" Score="1" ViewCount="44" Body="&lt;p&gt;Between &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Frontal_fog&quot; rel=&quot;nofollow noreferrer&quot;&gt;Frontal fog&lt;/a&gt; and &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Advection_fog&quot; rel=&quot;nofollow noreferrer&quot;&gt;Advection fog&lt;/a&gt; which covers larger territory ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If it's possible, provide some source of information as a proof&lt;/p&gt;&#xA;" OwnerUserId="18882" LastEditorDisplayName="user1066" LastEditDate="2020-02-08T01:53:09.183" LastActivityDate="2020-02-08T01:53:09.183" Title="What covers larger territory: advection fog or frontal fog?" Tags="|meteorology|scale|" AnswerCount="0" CommentCount="3" ClosedDate="2020-02-10T11:30:16.947" ContentLicense="CC BY-SA 4.0" />
  <row Id="19148" PostTypeId="2" ParentId="19145" CreationDate="2020-02-07T19:58:06.220" Score="6" Body="&lt;p&gt;Doing a quick calculation that looks to be around the wet-bulb temperature at the time of observation so that thermometer on the right side should be a hygrometer. Hygrometers measure the level of moisture in the air as opposed to a thermometer that measures the temperature level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: The calculation was based on a recorded observation scoured from &lt;a href=&quot;https://www.timeanddate.com/weather/antarctica/esperanza-base/historic&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; as finding the history of observations at the station was proving difficult. The observation marked a temperature around 64 degrees F with a relative humidity value of 34%. Using &lt;a href=&quot;https://www.omnicalculator.com/physics/wet-bulb&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; online based calculator which gives a rough estimate of the Wet Bulb Temperature, the calculated value came out to be 49.47 (F) or 9.7 (C) which was close enough for me to determine that the thermometer on the right was a hygrometer. Aiding that assumption was the fact that thermometers and hygrometers are sometimes paired together for observations.&lt;/p&gt;&#xA;" OwnerUserId="13660" LastEditorUserId="13660" LastEditDate="2020-02-10T19:37:48.643" LastActivityDate="2020-02-10T19:37:48.643" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19150" PostTypeId="2" ParentId="19125" CreationDate="2020-02-07T22:35:33.927" Score="1" Body="&lt;p&gt;There are active geological processes that lead to separation of mineral constituents. A source material that contains specific primary minerals, with some transport mechanism (eg convection or liquid flows) to physically separate them and 'trapping' conditions that allow them to accumulate are all required. Processes that result in minerals being separated from the source material include  - &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Magmatic - (within molten and partly molten magmas). Differential melting will allow specific minerals to melt and be squeezed out separately. Differential crystallisation will allow some minerals in a mixture to crystallise within a molten mass and (with changing temperature and/or pressure) to separate and reform as crystals and precipitate separately in more concentrated form in sediments at the base of a molten mass (or to rise where they are lower density than the surrounding material). Some materials can separate in their molten state, because they are immiscible (they don't mix or dissolve within each other), with similar separation because of differing density or pressure squeezing them out and solidify in concentrated forms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hydrothermal - minerals dissolving (usually in association with salts), with different temperature and pressures dissolving minerals preferentially. As liquid they can travel and come into contact with other minerals, resulting in chemical reactions, with potential for further differentiation.  Similar to differential crystallisation in magmas, specific minerals will crystallise and precipitate differentially out of concentrated water based solutions. Lots of sulphide mineral ore bodies were formed this way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Physical process like erosion and sedimentation also separate and concentrate existing minerals.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Answer in part from Wikipedia  - &lt;a href=&quot;https://en.wikipedia.org/wiki/Ore_genesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ore genesis&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2020-02-07T22:35:33.927" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19151" PostTypeId="1" CreationDate="2020-02-08T01:07:43.943" Score="6" ViewCount="3189" Body="&lt;p&gt;The question &lt;a href=&quot;https://earthscience.stackexchange.com/q/19145/6031&quot;&gt;What is the second thermometer in the image from the Esperanza Antarctic temperature record?&lt;/a&gt; shows what might be a wet/dry bulb setup.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've given one to a friend to measure humidity for fun (it's me who thinks it's fun). I'd learned about them in Earth Science class a zillion years ago, so when I happened to see one recently I grabbed it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I understand the very basics of how it can indicate humidity; the drier the air, the faster water will evaporate into it and so the colder the wet bulb will be with respect to the dry bulb.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To get a numerical value for humidity with this set up you use the coarse table on the front (there's a finer table on the back of the box) and look up the dry bulb temperature and the dry minus wet difference to find an approximate humidity. For example If I look up 19 and 2 °C for those respectively (roughly what's shown in the image) I get about 81% relative humidity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But suppose I hooked up a camera to a Raspberry Pi and imaged the two thermometers, processed the image and determined the two temperatures and wanted to calculate the relative humidity without interpolating the table.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; How is relative humidity determined from a wet and dry bulb readings? What are the steps and where's a good source for the equations and parameters involved?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Click for full size&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Yu941.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Yu941l.jpg&quot; alt=&quot;wet/dry bulb setup to measure relative humidity&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2021-07-19T10:36:45.120" LastActivityDate="2021-07-19T10:36:45.120" Title="How is relative humidity determined from a wet and dry bulb readings?" Tags="|measurements|humidity|instrumentation|mathematics|environmental-sensors|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19152" PostTypeId="1" CreationDate="2020-02-08T01:30:24.750" Score="8" ViewCount="324" Body="&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/19151/6031&quot;&gt;I have used&lt;/a&gt; a wet/dry bulb setup to estimate humidity, and &lt;a href=&quot;https://earthscience.stackexchange.com/q/19145/6031&quot;&gt;it appears that&lt;/a&gt; the Argentinian meteorological service uses one in Antarctica as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Hygrometer#Difficulty_of_accurate_humidity_measurement&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia sez&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Humidity measurement is among the more difficult problems in basic metrology. According to the WMO Guide, &quot;The achievable accuracies [for humidity determination] listed in the table refer to good quality instruments that are well operated and maintained. In practice, these are not easy to achieve.&quot; ...Hygrometers must be calibrated in air, which is a much less effective heat transfer medium than is water, and many types are subject to drift so need regular recalibration. A further difficulty is that most hygrometers sense relative humidity rather than the absolute amount of water present... &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; In practice, how do weather reporting stations measure humidity? Is there a difference between remote locations and those where people visit regularly? Does there tend to be a difference between instruments used in arctic and tropical conditions?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2021-07-19T10:36:13.110" LastActivityDate="2021-07-19T10:36:13.110" Title="How do the pros measure humidity?" Tags="|measurements|remote-sensing|humidity|field-measurements|environmental-sensors|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19153" PostTypeId="2" ParentId="19151" CreationDate="2020-02-08T04:36:41.227" Score="6" Body="&lt;p&gt;&lt;em&gt;Edit: 1 May 2021&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;The following procedure uses the less accurate method from page 455 onward from the scanned sections of the book pictured below, from the original answer.&lt;/p&gt;&#xA;&lt;p&gt;The procedure is a multistage process ideally suited to either a spreadsheet or programming code.&lt;/p&gt;&#xA;&lt;p&gt;The equations use SI units.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;1. Calculate the saturated vapor pressure at the dry bulb temperature&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is done using the equation:&#xA;&lt;span class=&quot;math-container&quot;&gt;$P''_{ws} \ = \ 0.61078\ e\ ^{17.27T_{dry}/(273.3+T_{dry})} \ \ kPa$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where &lt;span class=&quot;math-container&quot;&gt;$T_{dry}$&lt;/span&gt; is the dry bulb temperature.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;2. Calculate the saturated vapor pressure at the wet bulb temperature&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is done using the equation:&#xA;&lt;span class=&quot;math-container&quot;&gt;$P'_{ws} \ = \ 0.61078\ e\ ^{17.27T_{wet}/(273.3+T_{wet})} \ \ kPa$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where &lt;span class=&quot;math-container&quot;&gt;$T_{wet}$&lt;/span&gt; is the wet bulb temperature.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;3. Calculate the moisture content of saturated air at the wet bulb temperature&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Use the equation: &lt;span class=&quot;math-container&quot;&gt;$r_o \ = \ \frac{18.016 \ (1.0048)P'_{ws}} {28.9664 \ (P_{atm}-1.0048)P'_{ws}} \ \ kg/kg$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where &lt;span class=&quot;math-container&quot;&gt;$P_{atm}$&lt;/span&gt; is atmospheric pressure&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;4. Calculate the enthalpy of water vapor pressure at the wet bulb temperature&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$H'_{wo} \ = \ -0.00000662 \ t_{wet}^3-0.000194 \ t_{wet}^2+1.8375 \ t_{wet}+2500.83 \ \ kJ/kg$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;5. Calculate the enthalpy of liquid water at the wet bulb temperature&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$H'_{wl} \ = \ 0.0000063 \ t_{wet}^3-0.000727 \ t_{wet}^2+4.2058 \ t_{wet}+0.03 \ \ kJ/kg$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;6. Calculate the enthalpy of water vapor pressure at the dry bulb temperature&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$H'_{wi} \ = \ -0.00000662 \ t_{dry}^3-0.000194 \ t_{dry}^2+1.8375 \ t_{dry}+2500.83 \ \ kJ/kg$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;7. Calculate the moisture content of saturated air at the wet bulb temperature&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$r \ = \ \frac{r_o*(H'_{wo}-H'_{wl})-(1.005 \ t_{dry}-1.005 \ t_{wet})}{(H'_{wi}-H'_{wl})} \ \ kg/kg$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;8. Calculate the vapor pressure&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$P_w \ = \ \frac{r \ P_{atm}} {1.0048 \ (18.016/28.9664+r)} \ \ kPa$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;9. Calculate the relative humidity&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\phi \ = \ P_w/P''_{ws}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;Previous Answer - scans from relevant pages from reference book&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;I'm going to go old school with this one.&lt;/p&gt;&#xA;&lt;p&gt;The following pictures are the relevant pages from: &lt;em&gt;Environmental Engineering in South African Mines&lt;/em&gt;, The Mine Ventilation Society of South Africa, 1989, pp 451-455. They give the psychometric equations that are required to calculate relative humidity from wet &amp;amp; dry bulb temperatures.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DfrY7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DfrY7.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sKMCm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sKMCm.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5Zupk.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5Zupk.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/g4fNs.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/g4fNs.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZbbLp.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZbbLp.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;For simplicity, I use the less accurate equations on p455, section 9.2.&lt;/p&gt;&#xA;&lt;p&gt;As a slight diversion, the other way to measure &lt;a href=&quot;http://science.waltermack.com/VirtualFieldTrip/whirling.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;wet &amp;amp; dry bulb temperatures&lt;/a&gt; is to use a &lt;a href=&quot;https://www.aweimagazine.com/article/use-of-whirling-hygrometers-1137/&quot; rel=&quot;nofollow noreferrer&quot;&gt;whirling hygrometer&lt;/a&gt;. The wet bulb temperature is always read first because it will start to warm as soon as the hygrometer stops whirling.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oTa44.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oTa44.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-04-30T18:08:13.657" LastActivityDate="2021-04-30T18:08:13.657" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19155" PostTypeId="1" CreationDate="2020-02-08T09:51:24.290" Score="0" ViewCount="358" Body="&lt;p&gt;On Earth there is a clear space between the ground and the cloud base. This phenomenon is not confined to Earth, it's the same on Venus, Mars and Titan (moon of Saturn). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a law of physics which inhibits the formation of cloud at ground level? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Living in UK I know that ground fogs occur very occasionally, generally not lasting for more than a few hours, and for all we know it might be the same on the other planets, but it is not the normal state of affairs on the bodies mentioned above.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2020-02-09T21:09:51.630" LastActivityDate="2020-02-09T21:09:51.630" Title="Why is there a clear space between the ground and the cloud base?" Tags="|atmosphere|clouds|planets|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19156" PostTypeId="2" ParentId="19155" CreationDate="2020-02-08T12:01:56.163" Score="9" Body="&lt;p&gt;In my recently updated answer to the question: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/18344/what-the-humidity-metric-is-hiding&quot;&gt;&lt;em&gt;What the humidity metric is hiding?&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I cite a news article, originally dated 31 January 2020 : &lt;a href=&quot;https://www.abc.net.au/news/2020-01-31/hot-humid-weather-welcome-to-the-tropics/11917070&quot; rel=&quot;noreferrer&quot;&gt;&lt;em&gt;Oppressive, humid conditions for southern Australia as heatwave combines with tropical airmass&lt;/em&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the news article, meteorologists are quoted:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Dew point is the indicator of the amount of moisture in the air ... it's the temperature that the air needs to cool to in order to form cloud.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The only time clouds form on the Earth's surface (in the form of fog) is when the temperature of the air in contact with the surface is same as the dew point, for the prevailing weather conditions. Generally, air temperature near the Earth's surface is higher than the dew point so no fog/clouds form.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Clouds form at altitude because the air temperature at that altitude is the same as the  dew point temperature. Thus the reason for a gap between the surface and the base of clouds.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorDisplayName="user1066" LastEditDate="2020-02-08T15:44:00.830" LastActivityDate="2020-02-08T15:44:00.830" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="19157" PostTypeId="2" ParentId="19152" CreationDate="2020-02-08T12:20:52.617" Score="2" Body="&lt;p&gt;The Bureau of Meteorology in Australia &lt;a href=&quot;http://www.bom.gov.au/climate/cdo/about/airtemp-measure.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;traditionally uses&lt;/a&gt; wet and dry bulb thermometers read by humans, when measuring temperature. However, for remote automated weather stations, &lt;a href=&quot;http://media.bom.gov.au/social/blog/916/ask-bom-how-is-temperature-measured/&quot; rel=&quot;nofollow noreferrer&quot;&gt;electrical equipment&lt;/a&gt; is used. The dry bulb temperature is measured using a resistance temperature device (RTD) and relative humidity is measured using relative humidity probe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Bureau has produced a &lt;a href=&quot;https://www.youtube.com/watch?v=-qQHDGA7SsA&quot; rel=&quot;nofollow noreferrer&quot;&gt;video&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-02-08T12:20:52.617" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19158" PostTypeId="2" ParentId="19152" CreationDate="2020-02-08T13:23:43.080" Score="6" Body="&lt;p&gt;We use something like an Onset HOBO electronic sensor. They've got logging (and in some cases, networking) built in. They'll typically log both temperature and relative humidity at regular intervals specified by the user.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Humidity sensors have a tendency to wander off calibration, so you will need to take that into account when designing your monitoring protocol.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If it's a very inaccessible location, you might add extra duplicate sensors to allow you to compensate for this calibration issue.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://blog.servoflo.com/humidity-sensors-capacitive-vs-resistive&quot; rel=&quot;nofollow noreferrer&quot;&gt;Electronic RH sensors&lt;/a&gt; typically use a moisture-absorbing (hygroscopic) material, and either: a &lt;a href=&quot;https://docs.rs-online.com/1977/0900766b812af80a.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;capacitive sensor&lt;/a&gt; - as humidity increases, the capacitance of the sensor increases, as the sensor absorbs moisture from the air; or a resistive sensor - as humidity increases, the resistance decreases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Sensors that measure absolute humidity, do so by combining a measure of relative humidity, and a measure of temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And the suppliers will typically have different models that are rated for different conditions. The most expensive are sometimes called &quot;milspec&quot; - military specification - and are designed to particularly high standard for working in a wide range of extreme conditions.&lt;/p&gt;&#xA;" OwnerUserId="100" LastEditorUserId="100" LastEditDate="2020-02-08T22:34:47.093" LastActivityDate="2020-02-08T22:34:47.093" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19159" PostTypeId="1" CreationDate="2020-02-08T22:35:08.833" Score="5" ViewCount="338" Body="&lt;p&gt;I am a high school student who is thinking about going to university for Geological Sciences. I've had an interest in rocks and such since I was little, but I want to get an idea of what studying Geology at a post-secondary level would be like. I am looking for recommendations for high school/undergrad level books that would be accessible for a 16 year old, specifically on Mineralogy and Physical Geography (the areas I am most interested in). Thanks! &lt;/p&gt;&#xA;" OwnerUserId="17398" LastEditorUserId="18081" LastEditDate="2022-08-04T09:08:39.687" LastActivityDate="2022-08-04T09:08:39.687" Title="Introduction to Geology Books" Tags="|geology|mineralogy|reference-request|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19160" PostTypeId="2" ParentId="19159" CreationDate="2020-02-09T08:52:18.447" Score="4" Body="&lt;p&gt;I believe &lt;a href=&quot;https://books.google.es/books/about/Manual_of_mineralogy.html?id=8ybwAAAAMAAJ&amp;amp;redir_esc=y&quot; rel=&quot;nofollow noreferrer&quot;&gt;Manual of Mineralogy (based on Dana)&lt;/a&gt; is a good start for mineralogy and crystallography subjects. It is a good manual to understand the basics behind crystalls and minerals. It is a bit theoric, but it explain crystallography laws you need to know to face microscope. It also list the minerals by groups following Dana classification.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would recommend to chose recent introduction books to get a view about Earth Sciences in general, as modern tectonics has changed some concepts. That will cost you some chips; if that's a trouble, university libraries use to be open to public. You can go there and read any book published recently whose title look like &quot;Introduction to Earth Sciences&quot;. There are some books that specifically have a geophysics approach. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Talking about studying geology at a post-secondary level would be like, you need to know in geology field is the lab. In firsts courses you might find difficult to get it, but once you got the basic concepts, you will start to enjoy the Friday trips.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am going to recommend, if you have the opportunity, to join a geology summer camp. You can ask at the university you want to join if they have field introductory courses. You will need good shoes, a geology hammer, a compass, a magnifying glass and good attitude to learn new things.&lt;/p&gt;&#xA;" OwnerDisplayName="user18590" LastEditorDisplayName="user18590" LastEditDate="2020-02-09T11:46:36.103" LastActivityDate="2020-02-09T11:46:36.103" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19161" PostTypeId="2" ParentId="10128" CreationDate="2020-02-09T10:14:03.640" Score="-2" Body="&lt;p&gt;&quot;Logically this is the same as the net radiation downwards&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No, this is not the case. The atmosphere is almost black and opaque at certain wavelengths such as 15um (CO2). Then only the external layers radiate, mostly. The rest of the atmosphere transport heat by convection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The atmosphere is black because an absorbed IR photon energy will excite a CO2 molecule, for example, for a time which is 1000 x bigger than mean time between collisions in the case of low altitude. The molecule will deexcite through collision first.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Due to the gravity gradient, the top of the atmosohere is low pressure and mean time between collisions is much longer. We can see CO2 radiation from a thicker layer, this is the little glitch in the middle of the 15um band dip.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But at low altitude, only 10m of atmosphere will backradiate and the energy density is low because the temperature difference with earth is small.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The backradiation diagram from Nasa in ipcc AR4 is simply wrong. This happens (remember Mann hockeystick scandal).&lt;/p&gt;&#xA;" OwnerUserId="18894" LastActivityDate="2020-02-09T10:14:03.640" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19162" PostTypeId="2" ParentId="19127" CreationDate="2020-02-09T11:22:35.053" Score="4" Body="&lt;p&gt;I'm not sure how accurate you need, but beginning NASA's global 398.2 watts per square meter estimate from their energy budget a rounding down based on temperature variation should give a pretty good estimate.    A lot of people have a problem with that number because it's more energy than we get from the sun, but that's because our atmosphere is a kind of blanket that traps heat, which warms the Earth above it's planetary eqilibrium temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's also (but less so), higher because Earth is warmed from below as well as above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VPbI4.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VPbI4.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Diurnal_temperature_variation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Diurnal temperature variation&lt;/a&gt; is between highest day temperature and coldest night temperature and you're looking for average.  Using that number won't give a correct answer, but using, perhaps 1/2 that number might be in the range and that's over land.   The diurnal temperature variation over water is much lower.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, 288 Kelvin Earth, say 12 degree variation day to night, so 294 / 282.  Ratio of 1.0425, to the 4th power means 18% more heat is radiated from land during the day than at night.   Adjust the temperature if you think mine is off.    That's 18% x 29% of the surface area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For oceans, 71% of the surface area the temperature variation is smaller, say 2.5 degrees.   289.25 / 286.75, ratio of 1.0087.   4th power, means the oceans radiate about 3.5% more energy during the day than at night.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(18% x 29%) + (3.5% x 79%) = about 7.7%&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if Earth's surface radiation global average is about 398.2 w/m^2, then the day/night numbers work out to about 7.7% variation between them, or +/- 15.5 degrees, about 413.7 watts/m^2 during the day and about 382.7 at night.    That's a pretty good estimate I think.   I'm open to a better estimate if someone can think of a way to do it. &lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2020-02-09T11:22:35.053" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="19164" PostTypeId="1" CreationDate="2020-02-09T20:10:07.457" Score="3" ViewCount="262" Body="&lt;p&gt;Does anybody here have any experience with creating my own wrfchemi outputs from the emissions that are in different format, txt, netcdf and grib for instance? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I want to do, basically, is to use my own emissions inside the WRF/Chem model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have a netcdf and grib and txt of emissions of co2 and ch4 (gridded) with each grid having a value for the emissions.  I want to convert this to a readable format for the WRF/Chem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have read the emissions guide of the WRF/Chem, but it does not really expound on details about this especially about the following.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How to deal with the speciation (my data has co2 and ch4). Where exactly do I place this in the new emissions file (the wrfchemi) I want. There are many co2 and ch4 species there (like emi_co2, CO2FIRE, ppm, kg m**-2 s**-1). &lt;/p&gt;&#xA;" OwnerUserId="18881" LastEditorUserId="106" LastEditDate="2020-02-09T22:35:52.557" LastActivityDate="2020-02-09T22:35:52.557" Title="Create emission files by my data emission for wrf-chem" Tags="|wrf-chem|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19165" PostTypeId="2" ParentId="19134" CreationDate="2020-02-09T23:44:40.850" Score="6" Body="&lt;p&gt;This is a companion answer to both Erik's and tfb's answers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;tfb's answer assumes a uniform density throughout the Earth. This is highly inaccurate. Not to disparage tfb's answer; I've run across physics PhDs who thought that this was the correct model of gravitation inside the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem with this model is that the uniform density model is invalid for any object large enough to pull itself into a more or less spherical shape. In the case of our Earth, the mantle is significantly denser than is the crust, and the mantle's density increases with increasing depth due to increasing pressure. The core is much denser than is the mantle, by over a factor of two. The core's density increases with depth, and then jumps even a bit higher at the outer core / inner core boundary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Erik's answer (which is correct and should be the accepted answer) shows the flaws in this assumption. The uniform density assumption would suggest that gravitational acceleration at the core/mantle boundary should be a bit more than half of the gravitational acceleration at the surface. Erik's answer shows that it is in fact a bit over the gravitational acceleration at the surface. (No halfsies!) Rather than being roughly half the surface acceleration, gravitational acceleration reaches its maximum at the core/mantle boundary.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The graph in Erik's answer shows that in some places (e.g., the Earth's core) gravitational acceleration increases with increasing radial distance from the center of the Earth, but it decreases with increasing radial distance in other places. This answer addresses the conditions that make gravitational acceleration increase or decrease with increasing radial distance from the center of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll make the same assumption made in the Preliminary Reference Earth Model, which is that density inside the Earth depends only on radial distance from the center of the Earth. This means that Newton's shell theorem applies: The gravitational acceleration at some point inside the Earth depends only on the material closer to the center of the Earth than the point in question. Denoting &lt;span class=&quot;math-container&quot;&gt;$M(r)$&lt;/span&gt; as the mass of all of the material at a radial distance less than &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt;, then the gravitational acceleration at some point inside the Earth is &lt;span class=&quot;math-container&quot;&gt;$$g(r) = \frac{G M(r)}{r^2}\tag{1}$$&lt;/span&gt;&#xA;Differentiating with respect to &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; results in &lt;span class=&quot;math-container&quot;&gt;$$\frac{dg(r)}{dr} = \frac G{r^3}\left(r\frac{dM(r)}{dr} - 2M(r)\right)\tag{2}$$&lt;/span&gt;&#xA;One way to calculate &lt;span class=&quot;math-container&quot;&gt;$M(r)$&lt;/span&gt; is as a volume integral:&lt;span class=&quot;math-container&quot;&gt;$$M(r) = \int_0^r 4 \pi x^2 \rho(x) dx$$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$\rho(r)$&lt;/span&gt; is the local density at a radial distance &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; from the center of the Earth. Differentiating with respect to &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; results in &lt;span class=&quot;math-container&quot;&gt;$$\frac{dM(r)}{dr} = 4 \pi r^2 \rho(r)\tag{3}$$&lt;/span&gt;&#xA;Another way to express &lt;span class=&quot;math-container&quot;&gt;$M(r)$&lt;/span&gt; is via the average density &lt;span class=&quot;math-container&quot;&gt;$\bar\rho(r)$&lt;/span&gt; of all of the material at a radial distance less than &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt;:&lt;span class=&quot;math-container&quot;&gt;$$\bar \rho(r) \equiv \frac{M(r)}{V(r)} = \frac {M(r)}{\frac43 \pi r^3}$$&lt;/span&gt;&#xA;or &lt;span class=&quot;math-container&quot;&gt;$$M(r) = \frac43 \pi r^3 \bar \rho(r)\tag{4}$$&lt;/span&gt;&#xA;Applying equations (3) and (4) to (2) yields &lt;span class=&quot;math-container&quot;&gt;$$\frac{dg(r)}{dr} = 4 \pi G\left(\rho(r) - \frac23\bar\rho(r)\right)\tag{5}$$&lt;/span&gt;&#xA;In other words, gravitational acceleration increases with increasing distance from the center of a planet in regions where the local density is more than two thirds of the average density of all of the stuff at a lesser distance, but decreases with increasing distance in regions where the local density is less than this limit. In the case of a hypothetical uniform density planet, the local density is equal to the average density and thus gravitational acceleration increases from the center up to the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But in the case of the Earth, there's a very large drop in density at the core-mantle boundary, enough of a drop to make the local density less than the critical two thirds of the average density of all the stuff below. The core mantle boundary is where gravitational acceleration reaches a global maximum. Another marked drop in density occurs at the upper mantle-lower mantle boundary, making gravitational acceleration decrease from there to the surface. The upper mantle-lower mantle boundary is where gravitational acceleration achieves a local (but not global) maximum.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-02-09T23:44:40.850" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19166" PostTypeId="2" ParentId="19146" CreationDate="2020-02-10T03:42:37.447" Score="6" Body="&lt;p&gt;Above the asthenosphere is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Lithosphere&quot; rel=&quot;noreferrer&quot;&gt;lithosphere&lt;/a&gt;. The main constituent of the lower lithosphere is &lt;a href=&quot;https://en.wikipedia.org/wiki/Peridotite&quot; rel=&quot;noreferrer&quot;&gt;peridotite&lt;/a&gt;, a coarse-grained igneous rock containing the minerals &lt;a href=&quot;https://en.wikipedia.org/wiki/Olivine&quot; rel=&quot;noreferrer&quot;&gt;olivine&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Pyroxene&quot; rel=&quot;noreferrer&quot;&gt;pyroxene&lt;/a&gt;. Samples of peridotite can be found in the surface. Sections of ocean crust can be uplifted onto continental margins, forming &lt;a href=&quot;https://en.wikipedia.org/wiki/Ophiolite#Formation_and_emplacement&quot; rel=&quot;noreferrer&quot;&gt;ophiolites&lt;/a&gt; (perhaps the best-known example being the &lt;a href=&quot;https://en.wikipedia.org/wiki/Troodos_Ophiolite&quot; rel=&quot;noreferrer&quot;&gt;Troodos Ophiolite&lt;/a&gt;). They are also found as fragments in basalts and &lt;a href=&quot;https://en.wikipedia.org/wiki/Kimberlite&quot; rel=&quot;noreferrer&quot;&gt;kimberlites&lt;/a&gt;, the vertical intrusions that often contain diamonds. So there are lots of places on the surface where you can go and see what the upper mantle looks like! But in the meantime, a closeup of a peridotite is shown below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UpGIV.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UpGIV.jpg&quot; alt=&quot;Closeup of peridotite from Wikimedia Commons (https://commons.wikimedia.org/wiki/File:Peridotite_closeup.jpg)&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="10764" LastActivityDate="2020-02-10T03:42:37.447" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19167" PostTypeId="2" ParentId="19159" CreationDate="2020-02-10T04:54:46.617" Score="2" Body="&lt;p&gt;&quot;Principles of Igneous and Metamorphic Petrology&quot; by John D. Winter is a good book to get into when you get past the basics and want to learn more about petrology, as it also touches into concepts of density gradients of the earth and the creation of the galaxy. It is pretty pricey so if you found a used one for cheap or a PDF online I would recommend you read it as it gives most of the terminology you would be needing as a geologist. Agreeing with Universal_learner, Dana has great books to start out on and learn mineralogy and crystallography.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One of the things that I wish I took earlier on in my learning career was field geology because it really solidifies everything that you learned in class and read about in text by actually practicing the concepts. A little bit of advice for hands on labs is to actually take your time and exam your rock with a loupe, understanding the textures, and how that correlates with its formation.&lt;/p&gt;&#xA;" OwnerUserId="18859" LastActivityDate="2020-02-10T04:54:46.617" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19168" PostTypeId="2" ParentId="19152" CreationDate="2020-02-10T11:58:50.597" Score="10" Body="&lt;p&gt;The WMO report &lt;a href=&quot;https://extranet.wmo.int/pages/prog/www/IMOP/CIMO-Guide.html&quot; rel=&quot;noreferrer&quot;&gt;Instruments and Methods of Observation&lt;/a&gt; has a chapter on &lt;a href=&quot;http://library.wmo.int/opac/doc_num.php?explnum_id=3151&quot; rel=&quot;noreferrer&quot;&gt;Measurement of humidity&lt;/a&gt; and a separate chapter on &lt;a href=&quot;http://library.wmo.int/opac/doc_num.php?explnum_id=3158&quot; rel=&quot;noreferrer&quot;&gt;Measurement of upper-air pressure, temperature, humidity&lt;/a&gt;. The first deals with instruments used for surface measurements. The second deals with instruments used for measuring vertical profiles, which have to deal with a larger range of temperatures and pressures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the surface instruments they list:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Gravimetric: take an air sample, extract all the water and weigh it (typically  used for calibration);&lt;/li&gt;&#xA;&lt;li&gt;Chilled mirror: dewpoint or frostpoint: used for observations and for calibration;&lt;/li&gt;&#xA;&lt;li&gt;Salt-solution: matching vapour pressure of a salt solution to atmospheric vapour pressure: used in automated weather stations;&lt;/li&gt;&#xA;&lt;li&gt;Psychrometric: comparing wet or ice bulb temperature with actual temperature - used in observations and calibration;&lt;/li&gt;&#xA;&lt;li&gt;Sorption methods: using hair or an alternative which stretches when wet, or using a material with a electrical resistance or capacitance that changes when wet.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;In other words, the professionals use a lot of different methods.&lt;/p&gt;&#xA;" OwnerUserId="17518" LastActivityDate="2020-02-10T11:58:50.597" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19169" PostTypeId="2" ParentId="19146" CreationDate="2020-02-10T12:39:05.747" Score="5" Body="&lt;p&gt;To complete the first answer with bigger scale images, here are some pictures of well-known mantle outcrops in Italy and Corsica (figure 4 from &lt;a href=&quot;https://doi.org/10.1016/j.gsf.2018.11.001&quot; rel=&quot;noreferrer&quot;&gt;Rampone et al. 2020&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/C7JL8.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/C7JL8.jpg&quot; alt=&quot;mantle outcrops&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The caption reads:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;(a) Centimeter-thick pyroxenite layers embedded in the External Ligurides mantle peridotites (Northern Apennines). (b) Partially dissolved pyroxenite layers (substituted by olivine) in reactive spinel peridotites (Erro-Tobbio, Ligurian Alps). (c) Replacive dunite (including pyroxene relics) grading to harzburgite (Lanzo, Western Alps). (d) Spinel peridotite grading to impregnated plagioclase-bearing peridotite (Mt. Maggiore, Alpine Corsica). (e) Two parallel layers of partially dissolved spinel pyroxenites (substituted by olivine) embedded in spinel peridotites. Both peridotite and associate pyroxenites display subsequent plagioclase enrichment related to melt impregnation (see text for more explanation). (f) Plagioclase-rich iso-oriented veinlets in impregnated peridotite.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You can find similar pictures in &lt;a href=&quot;https://doi.org/10.1016/j.lithos.2006.07.002&quot; rel=&quot;noreferrer&quot;&gt;Piccardo et al. 2007&lt;/a&gt;, or in &lt;a href=&quot;https://doi.org/10.3809/jvirtex.2010.00219&quot; rel=&quot;noreferrer&quot;&gt;Piccardo 2010&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Wikipedia article &quot;Peridotite&quot; given in the other answer has some details about those different lithologies:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;Dunite: more than 90% olivine, typically with Mg/Fe ratio of about 9:1.&lt;/li&gt;&#xA;  &lt;li&gt;Wehrlite: mostly composed of olivine plus clinopyroxene.&lt;/li&gt;&#xA;  &lt;li&gt;Harzburgite: mostly composed of olivine plus orthopyroxene, and relatively low proportions of basaltic ingredients (because garnet and clinopyroxene are minor).&lt;/li&gt;&#xA;  &lt;li&gt;Lherzolite: most common form of peridotite, mostly composed of olivine, orthopyroxene (commonly enstatite), and clinopyroxene (diopside), and have relatively high proportions of basaltic ingredients (garnet and clinopyroxene). Partial fusion of lherzolite and extraction of the melt fraction can leave a solid residue of harzburgite.&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;To simplify, lherzolite is a &quot;fertile&quot; peridotite, i.e. a peridotite that can (partially) melts. When melt is extracted, it becomes a harzburgite and eventually a dunite, which are &quot;depleted&quot;, refractory peridotites. &lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-02-10T12:39:05.747" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19170" PostTypeId="1" CreationDate="2020-02-05T11:23:31.243" Score="5" ViewCount="196" Body="&lt;p&gt;With the increase in carbon dioxide and the warming of the Earth's surface, some surfaces change colour and reflect light differently. In general, there is a decrease in light areas and an increase in dark areas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can the measurement of the albedo show this difference, or is it too small?&lt;/p&gt;&#xA;" OwnerUserId="18909" OwnerDisplayName="Jean Dumont" LastEditorUserId="18909" LastEditDate="2020-02-11T12:06:38.857" LastActivityDate="2020-02-12T17:23:52.397" Title="Terrestrial albedo" Tags="|climate|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19171" PostTypeId="2" ParentId="19170" CreationDate="2020-02-05T13:22:12.077" Score="7" Body="&lt;p&gt;The two biggest changes are fairly straight forward.  Ice cover and Ocean area.   During the peak of the last ice age, ice extended over most of Canada, maybe half of Russia and parts of the Northern United States and snow probably extended well south of that during winter.   Ice has a high albedo.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As glaciers grow, ocean cover decreases.  The yellow on this map indicates loss of ocean cover and increase in land.   Oceans have low albedo, which means shrinking oceans also raises Earth's albedo.   As a rule, during glaciation periods, Earth's albedo is higher and more light gets reflected directly back into space, which fits with the planet getting colder.   This is one of the ice age feedback mechanisms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jeXVx.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jeXVx.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://atmos.washington.edu/~dennis/OCC_Final_961216.html&quot; rel=&quot;noreferrer&quot;&gt;Source of image&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other factors may be less predictable, like deserts have comparatively high albedo and forests, lower albedo and the Sahara, for example, becomes partially forested over depending on variations in weather patterns driven primarily by Milankovich cycles (not necessarily in sync with ice age cycles), but I suspect, compared to the ice and ocean surface area changes, desert to forest changes have less effect.   &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Today's global warming is expected to (and already has) decreased ice and show cover, which lowers albedo and this trend is expected to continue.   Over time, enough glacial ice might melt that oceans become measurably larger as well.   This ice melt and ocean expansion lowers albedo further and is one of the positive feedbacks that effects and is expected to continue to effect man made climate change.&lt;/p&gt;&#xA;" OwnerUserId="2717" OwnerDisplayName="userLTK" LastActivityDate="2020-02-05T13:49:25.733" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19172" PostTypeId="2" ParentId="19170" CreationDate="2020-02-10T21:40:09.703" Score="3" Body="&lt;p&gt;In addition to the other answer (which I think covers the really big effects), things like changes in vegetation type and amount, which can happen as a result of change in temperature (as well as because, for instance, humans both cultivate crops and remove or even plant forests) change the albedo.  However this change is complicated: vegetation typically lowers albedo, but it also increases evaporation of water (known as 'evapotranspiration' which tends to cool the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These changes are certainly modelled in some earth system models (see for instance &lt;a href=&quot;https://ukesm.ac.uk/&quot; rel=&quot;nofollow noreferrer&quot;&gt;UKESM&lt;/a&gt;), and things like vegetation cover and type is the sort of thing that can be observed by satellites: see &lt;a href=&quot;https://earthobservatory.nasa.gov/features/MeasuringVegetation/measuring_vegetation_4.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;this NASA page&lt;/a&gt; for instance.  Additionally albedo can be measured directly: see for instance &lt;a href=&quot;https://earthobservatory.nasa.gov/images/84499/measuring-earths-albedo&quot; rel=&quot;nofollow noreferrer&quot;&gt;this page&lt;/a&gt; (also NASA).  So these changes certainly do change albedo measurably, although I suspect to a smaller extent than large-scale changes in ice cover.&lt;/p&gt;&#xA;" OwnerDisplayName="user18801" LastEditorDisplayName="user18801" LastEditDate="2020-02-12T17:23:52.397" LastActivityDate="2020-02-12T17:23:52.397" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19173" PostTypeId="1" CreationDate="2020-02-10T22:59:52.543" Score="3" ViewCount="117" Body="&lt;p&gt;Probability aside regarding their visibility (I did read on Neil Davies Aurora watcher's handbook that probability is highest in the middle of their latitude range called aurora oval, lowering both north and south of it), do they show the same visual effects all along their latitude range?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it just the angle compared to the viewer that would change (closer to the middle of their range one would be seeing them overhead, farther from the middle range one would be seeing them across the horizon)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, during a geomagnetic storm that NOAA classifies as 3 (Kp=7), what would be the visual difference between a viewer located at the limiting visibility latitude of Kp=5 and Kp=3?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Would the visibility oval shift southward instead of increasing in width and hence also shift the middle of its visibility latitude range southwards? Animations I have seen on NOAA 30 minutes forecast seem to support the latter, however it was just eyeballed and not quantitatively assessed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Weather conditions all the same, is the best viewing line in the middle of the latitude range or is it simply the most probable line in which it'd be visible? Or would it have added benefits other than probability?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/bBqwk.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="18904" LastEditorUserId="39" LastEditDate="2020-02-11T10:25:55.777" LastActivityDate="2020-02-11T10:25:55.777" Title="Do northern lights (aurora borealis) show the same visual activity all along their visible latitude range?" Tags="|geophysics|sun|auroras|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19174" PostTypeId="1" CreationDate="2020-02-11T10:03:50.323" Score="4" ViewCount="645" Body="&lt;p&gt;It appears that all GHGs are first translated into Carbon Dioxide Equivalents (CDEs) and that calculation is fairly straight forward. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many report in tonnes of Carbon instead of tonnes CDE. I am unsure how this is calculated:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Actually count the carbon atoms in each species&lt;/li&gt;&#xA;&lt;li&gt;Pretend that they really Carbon Dioxide, and simply apply 12/44 to tonnes of CDE to get a CDE carbon content. For example, nitric oxide has a CDE value but no actual carbon, but you can come up with a carbon mass using this approach.&lt;/li&gt;&#xA;&lt;li&gt;Some other method&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Is there a prescribed approach or standard basis?&lt;/p&gt;&#xA;" OwnerUserId="18906" LastEditorUserId="6" LastEditDate="2020-02-12T11:53:40.867" LastActivityDate="2020-02-17T16:20:51.823" Title="Which method is used to calculate tonnes carbon from tonnes CO$_2$ equivalents of GHGs?" Tags="|climate-change|greenhouse-gases|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19175" PostTypeId="1" CreationDate="2020-02-11T10:37:14.780" Score="1" ViewCount="80" Body="&lt;p&gt;Does anyone know how to calculate the vertical integrated moisture flux using NCL or Grads if you share a NCL script I'm very thankful to you.&lt;/p&gt;&#xA;" OwnerUserId="18908" LastActivityDate="2020-02-11T10:37:14.780" Title="vertical integrated moisture flux" Tags="|meteorology|atmosphere|models|atmosphere-modelling|" AnswerCount="0" CommentCount="1" ClosedDate="2020-02-11T14:59:49.930" ContentLicense="CC BY-SA 4.0" />
  <row Id="19176" PostTypeId="2" ParentId="19006" CreationDate="2020-02-11T10:50:44.533" Score="5" Body="&lt;p&gt;You need to use the following line in your model setup:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;COORDINATES SPHERICAL&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Otherwise SWAN will try to calculate wave properties on a curvilinear grid with coordinates provided in meters. In your present case, the computational area is 0.47 m x 0.24 m instead of degrees longitude and latitude.&lt;/p&gt;&#xA;" OwnerUserId="18907" LastActivityDate="2020-02-11T10:50:44.533" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19177" PostTypeId="1" CreationDate="2020-02-11T12:51:56.273" Score="3" ViewCount="131" Body="&lt;p&gt;At the moment around mexico we can find the leftovers of the Chicxulub impactor which could have extincted most dinosaurs. But 66 million years ago was after the breakdown of Gondwana. So back to those days where did exactly (probably approximately) hit the meteorite. Was it far from Yucatan?&lt;/p&gt;&#xA;" OwnerUserId="5372" LastEditorUserId="5372" LastEditDate="2020-02-11T15:49:36.810" LastActivityDate="2020-02-11T15:49:36.810" Title="What were the geometric coordinates of the Chicxulub impactor 66 million years ago?" Tags="|plate-tectonics|earth-history|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19178" PostTypeId="1" AcceptedAnswerId="19186" CreationDate="2020-02-11T14:21:41.197" Score="6" ViewCount="726" Body="&lt;p&gt;Anyone who has studied ice ages would know that during the last two-and-a-half million years of Earth's history, there have been periods where there was enough ice to suck up a lot of water. As a result, sea levels fell by an average of 100 meters. Among the most famous examples of this sort of drop is Beringia, the landmass that connected North America to Asia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, that doesn't seem to be the only way to reduce sea levels.  On the image below is how much North America changed in only less than ten million years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Gi2UP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Gi2UP.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the left is what North America looked like 75 million years ago.  On the right is North America at the time the dinosaur empire fell nine million years later.  It's not just North America that experienced this drop.  As a matter of fact, the whole world was undergoing the same process (it's just that I couldn't find one compatible enough to post in this SE.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The big deal with that is that unlike in the Ordovician, Carboniferous, Permian or Quaternary periods, this marine regression was not because of ice, as its extent (therefore its influence) was barely minimal--&lt;strong&gt;&lt;em&gt;alpine&lt;/em&gt;&lt;/strong&gt; at the very best.  There was no massive pileup of polar ice as was the case in the other periods listed last sentence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;So if ice weren't the cause of the sea levels dropping during the latest Cretaceous age, then what else could cause the same thing to happen?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="4985" LastEditorUserId="4985" LastEditDate="2020-02-13T10:36:01.617" LastActivityDate="2020-02-13T10:36:01.617" Title="What Caused The Sea Levels to Drop During the Maastrichtian Epoch?" Tags="|earth-history|sea-level|paleogeography|cretaceous|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19179" PostTypeId="2" ParentId="19177" CreationDate="2020-02-11T15:33:23.037" Score="1" Body="&lt;p&gt;Sixty six million years ago the Chicxulub meteorite struck the Yucatan peninsular in the same place as the crater is today. The peninsular hasn't moved very far since then, though some of the continents have, India for example. South America was already well adrift from Africa. At the time, most of Yucatan was probably under a shallow sea, too shallow to slow the impact to any great extent. Struck at that speed (about 55 km per sec), water is as solid as stone, but 50 feet of stone would have done little to slow the speed of such a large bolide. The water and much of the rock beneath it was vaporised.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-02-11T15:33:23.037" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19181" PostTypeId="2" ParentId="6981" CreationDate="2020-02-11T22:24:30.127" Score="0" Body="&lt;p&gt;My guess would be that the temperature of seawater has something to do with it. In the wintertime and in the early spring the seawater is colder in the northern hemispere and can absorb more carbon dioxide. In the summertime and fall the water is warmer and will release some CO2. This will explain the seasonal pattern of stations in the northern hemisphere. The further north you come the difference between summer and winter temperature will increase and therefore the amplitude of the seasonal cycles. &lt;/p&gt;&#xA;" OwnerUserId="18912" LastActivityDate="2020-02-11T22:24:30.127" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19182" PostTypeId="1" CreationDate="2020-02-12T01:04:37.400" Score="7" ViewCount="273" Body="&lt;p&gt;How much heat was released from the 2019-2020 Australian bush fires? And is that likely to have a measurable impact on global atmospheric heat content?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe as a secondary question: How much impact will the CO2 released by the fires have? And (maybe a bit to hard to answer) how much will regrowth draw down?&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2020-02-18T01:18:43.837" Title="How much heat was released from the 2019-2020 Australian bush fires?" Tags="|climate-change|co2|wildfire|fire|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19184" PostTypeId="2" ParentId="19174" CreationDate="2020-02-12T09:10:57.647" Score="8" Body="&lt;p&gt;OK it depends a lot on what exactly you mean. There is a known problem with people talking about &quot;carbon&quot; / &quot;atmospheric carbon&quot; / &quot;Carbon Dioxide&quot; and using the terms imprecisely - so there is often a confusion about which exact chemical species is being discussed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Tonnes of C to CO&lt;sub&gt;2&lt;/sub&gt; is (as you correctly stated) a conversion based on molecular mass, but this doesn't really help us if we're talking about something like methane which contains carbon, but has a dramatically different effect in terms of global warming. It is even more complicated when you take into account the change in lifespan of these different species (methane degrades in the atmosphere &lt;em&gt;much&lt;/em&gt; more quickly than CO&lt;sub&gt;2&lt;/sub&gt; for example)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The usual method to deal with this is to calculate &lt;a href=&quot;https://en.wikipedia.org/wiki/Global_warming_potential&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Warming Potential&lt;/a&gt; (GWP). This compares the actual radiative forcing over time (the change in the earth's energy balance) to a fixed time horizon (usually 100 years) when compared with CO&lt;sub&gt;2&lt;/sub&gt;. We can therefore compare the actual equivalent effects of releasing a number of different gasses in units of CO&lt;sub&gt;2&lt;/sub&gt; equivalent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The details of how it's calculated and why the time horizons are where they are is in the &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/07/WGI_AR5.Chap_.8_SM.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC AR5 WG1 CH8 technical supplement&lt;/a&gt; (8.SM.11.1 Equations for the Global Warming Potential)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this helps&lt;/p&gt;&#xA;" OwnerUserId="18621" LastEditorUserId="18621" LastEditDate="2020-02-17T16:20:51.823" LastActivityDate="2020-02-17T16:20:51.823" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19185" PostTypeId="2" ParentId="19182" CreationDate="2020-02-12T09:49:57.067" Score="9" Body="&lt;p&gt;Right. We can make some estimates of the scale of the problem, but they will come with a healthy margin of error.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;If we assume that wood has a calorific value of 18.5 GJ/t (from the &lt;a href=&quot;https://phyllis.nl/Browse/Standard/ECN-Phyllis&quot; rel=&quot;nofollow noreferrer&quot;&gt;phyllis2&lt;/a&gt; database)&lt;/li&gt;&#xA;&lt;li&gt;The area burned is 18.6 Mha (from Wikipedia &lt;a href=&quot;https://en.wikipedia.org/wiki/2019%E2%80%9320_Australian_bushfire_season&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;The standing volume of material is circa 1500 m&lt;sup&gt;3&lt;/sup&gt;/ha (an educated guess based on Eucalyptus values in &lt;a href=&quot;https://www.forestresearch.gov.uk/tools-and-resources/forest-yield/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Forest Yield&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;The density of timber is circa 0.5t per dry m&lt;sup&gt;3&lt;/sup&gt; (from &lt;a href=&quot;https://www.forestresearch.gov.uk/research/forest-mensuration-a-handbook-for-practitioners/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Forest mensuration handbook&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;and only 90% of that material actually burns (a guess)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Then:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's around 675 tonnes of material burned per ha releasing 12,150 GJ of energy which is equal to 225,990,000 TJ for the total area or 3,587,143 Hiroshima bombs (at &lt;a href=&quot;https://en.wikipedia.org/wiki/Little_Boy&quot; rel=&quot;nofollow noreferrer&quot;&gt;63 TJ each&lt;/a&gt;)...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is a (very) rough calculation, but it gives a scale of the amount of heat released. This is about 10 day's worth of &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_constant&quot; rel=&quot;nofollow noreferrer&quot;&gt;solar constant&lt;/a&gt; radiation over the same area, so it might appear in local temperature readings, but bear in mind that 1) there was already unusually high temperatures in the area, and 2) fires like this produce a lot of smoke which will have had an effect on the local radiation budget.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In terms of all that CO&lt;sub&gt;2&lt;/sub&gt;, you can expect it to be reabsorbed by the surrounding biosphere which is described in the impulse response function described in the IPCC AR5 WG1 CH8 technical supplement (&lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/07/WGI_AR5.Chap_.8_SM.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;8.SM.11.1 Equations for the Global Warming Potential&lt;/a&gt;). You can also expect the burned areas to regrow - which will absorb CO&lt;sub&gt;2&lt;/sub&gt; as well. Depending on rates of growth, I would expect this to take several decades. - but there is a &lt;em&gt;lot&lt;/em&gt; of very complex processes, so this is open to a lot of discussion!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this helps.&lt;/p&gt;&#xA;" OwnerUserId="18621" LastEditorUserId="5282" LastEditDate="2020-02-17T16:17:32.630" LastActivityDate="2020-02-17T16:17:32.630" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="19186" PostTypeId="2" ParentId="19178" CreationDate="2020-02-12T10:19:42.040" Score="6" Body="&lt;p&gt;Tectonic activity can change the volume of oceanic basins and hence, modify the sea level, ice not involved.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Firstly let's explain the left picture. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At Cretaceous the tectonic activity was high. The flux of material from mantle to ocean ridges and plateaux reduced the volume of ocean basins, wich produced a global high sea-level observed in differents parts of the globe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During Campanian and Mastrichtian global transgressions are recognized in several stratigraphic sections of the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Z. Dubicka and D. Peryt (2012) studied a stratigraphic sequence in Poland wich also showed transgression phases on Mastrichtian. They correlated them with other strata of the age.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This sea-level rise, recorded in south-eastern Poland, can be&#xA;  correlated with the transgressive peak recognized by Hancock (1993);&#xA;  this corresponds to the Craise Graise (¼ Vijlen Member) exposed in the&#xA;  CPL quarry at Halembaye in Belgium, which in turn corresponds to the&#xA;  lower Belemnitella junior Zone, i.e., earliest Late Maastrichtian.&#xA;  Hancock (1993) suggested that this peak may occur globally. He&#xA;  correlated it with the Prairie Bluff Chalk on the northern margin of&#xA;  the Gulf of Mexico and with strata that lie a little above the base of&#xA;  the Tinton Greensand on the Atlantic coastal plain. The transgressive&#xA;  peak in the earliest Late Maastrichtian was also documented in the&#xA;  Sopelana section in the Basque Arc Domain in Spain (Gómez-Alday et&#xA;  al., 2004), which coincides with the inoceramid extinction, the&#xA;  informal definition of the Lower/Upper Maastrichtian boundary.&#xA;  Moreover, a marked transgression in the middle Maastrichtian was&#xA;  reported from the Southern Hemisphere by Huber and Watkins (1992) who&#xA;  noted a higher diversity of keeled foraminifera, which they&#xA;  interpreted as reflecting a possible transgression.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Then let's focus in your question about the sea level drop. It is pretty obvious a regression happened, at least at North America.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sea level drop appears to be global too, according to Matsumoto (2002) and associated to a slowing down of global tectonic activity. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Tectono-eustasy may have been the main cause of the phenomena of&#xA;  transgression-regression, but certain kinds of other tectonic&#xA;  movements which affected even the so-called stable platforms were also&#xA;  responsible for the phenomena. The combined effects of various causes&#xA;  may have been unusual in the Cretaceous, since it was a period of&#xA;  global tectonic activity. The slowing down of this activity followed&#xA;  by readjustments may have been the cause of the global regression at&#xA;  the end of the Cretaceous.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Zofia Dubicka, Danuta Peryt (2012): &quot;Latest Campanian and Maastrichtian palaeoenvironmental changes: Implications from an epicontinental sea (SE Poland and western Ukraine)&quot;, Cretaceous Research&#xA;Volume 37, October 2012, Pages 272-284.&#xA;&lt;a href=&quot;https://doi.org/10.1016/j.cretres.2012.04.009&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/j.cretres.2012.04.009&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;T.Matsumoto (2002): &quot;Inter-regional correlation of transgressions and regressions in the Cretaceous period&quot;, Palaeogeography, Palaeoclimatology, Palaeoecology. Volume 187, Issues 1–2, 1 November 2002, Pages 35-60&#xA;&lt;a href=&quot;https://doi.org/10.1016/S0031-0182(02)00504-7&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/S0031-0182(02)00504-7&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user18590" LastEditorDisplayName="user18590" LastEditDate="2020-02-12T13:46:06.093" LastActivityDate="2020-02-12T13:46:06.093" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19187" PostTypeId="1" CreationDate="2020-02-12T14:45:10.273" Score="1" ViewCount="77" Body="&lt;p&gt;I am writing an essay about &lt;a href=&quot;https://en.wikipedia.org/wiki/Whakaari_/_White_Island#2019_eruption&quot; rel=&quot;nofollow noreferrer&quot;&gt;White Island’s 2019 eruption&lt;/a&gt;, and I need to know if the eruption was directly triggered by people. Is it possible that it was? Whether it being quarrying, too much tourism etc.?&lt;/p&gt;&#xA;" OwnerUserId="18917" LastEditorUserId="595" LastEditDate="2020-02-12T16:08:59.223" LastActivityDate="2020-02-12T16:08:59.223" Title="Did people trigger the White Island 2019 eruption?" Tags="|volcanology|geography|" AnswerCount="0" CommentCount="0" ClosedDate="2020-02-14T12:18:50.053" ContentLicense="CC BY-SA 4.0" />
  <row Id="19188" PostTypeId="1" CreationDate="2020-02-13T01:06:31.483" Score="8" ViewCount="340" Body="&lt;p&gt;I am looking for any studies or maps detailing the average salinity and temperature for areas of the Earth's oceans. As an extra if anyone has data or maps on areas with large amounts of in-trained silts or aggressive sea life (muscles/barnacles) that would be a huge help. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Purpose: I would like to write a paper for Navy engineers on specific world areas of concern for equipment operation utilizing seawater cooling systems. That way we can gear our preventive maintenance to account for these problems. &lt;/p&gt;&#xA;" OwnerUserId="18923" LastEditorUserId="2470" LastEditDate="2020-02-13T19:54:58.400" LastActivityDate="2020-02-14T17:02:36.107" Title="Most corrosive seawater areas in world" Tags="|oceanography|geochemistry|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19189" PostTypeId="1" AcceptedAnswerId="19222" CreationDate="2020-02-13T02:59:39.240" Score="5" ViewCount="380" Body="&lt;p&gt;In an episode of History Channel's &lt;em&gt;How the Earth Was Made&lt;/em&gt;, there was a remark when India left the rest of Gondwana 80 million years ago only to collide with mainland Asia 50.5 million years ago.  The remark was, &quot;very fast in geological time.&quot;  Afterwards, it was said that &quot;as with any smash, the faster the collision, the bigger the wreck.&quot;  In the episode, those remarks were written as an explanation for the Himalayas' &quot;unique size&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But is this true?  Could the speed in which one plate collides with another REALLY affect the size of a mountain range?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastEditorUserId="6" LastEditDate="2020-04-11T11:53:24.240" LastActivityDate="2020-04-11T11:53:24.240" Title="Could the speed in which the plate is moving affect how quickly mountains rise?" Tags="|plate-tectonics|mountains|mountain-building|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19190" PostTypeId="2" ParentId="19182" CreationDate="2020-02-13T03:37:16.983" Score="4" Body="&lt;p&gt;&lt;strong&gt;EDIT&lt;/strong&gt;: As pointed out by Jean-Marie Prival and klanomath in the comments, I originally misread the specific heat of wood as per tonne, rather than per kilogram, and also used the wrong conversion between TWh and TJ.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are my rough calculations, based on CO2-release estimates from NASA:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;306 MtCO2 (&lt;a href=&quot;https://en.wikipedia.org/wiki/2019%E2%80%9320_Australian_bushfire_season#Environmental_effects&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;Wood spec energy = 4.50 kWh/kg (&lt;a href=&quot;https://www.engineeringtoolbox.com/co2-emission-fuels-d_1085.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;engineeringtoolbox.com&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;Wood spec CO2 = 1.83 kg CO2/kg fuel (&lt;a href=&quot;https://www.engineeringtoolbox.com/co2-emission-fuels-d_1085.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;engineeringtoolbox.com&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$\Rightarrow$&lt;/span&gt; wood burnt = 167.2 Mt = &lt;span class=&quot;math-container&quot;&gt;$1.67\times10^{11}$&lt;/span&gt; kg&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$\Rightarrow$&lt;/span&gt; energy released &lt;span class=&quot;math-container&quot;&gt;$\approx 7.525\times10^{11}$&lt;/span&gt; kWh&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;1KWh = &lt;span class=&quot;math-container&quot;&gt;$3.6\times 10^{-6}$&lt;/span&gt; TJ&lt;/li&gt;&#xA;&lt;li&gt;= &lt;span class=&quot;math-container&quot;&gt;$2.708\times10^{6}$&lt;/span&gt; TJ&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;Hiroshima = 54-75 TJ (&lt;a href=&quot;https://www.engineeringtoolbox.com/co2-emission-fuels-d_1085.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$\Rightarrow$&lt;/span&gt; Aus Bushfires &lt;span class=&quot;math-container&quot;&gt;$\approx$&lt;/span&gt; 36k-50k Hiroshima bombs worth of heat.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;According to the &lt;a href=&quot;https://nypost.com/2020/01/15/ocean-is-warming-at-rate-of-5-hiroshima-nukes-a-second/&quot; rel=&quot;nofollow noreferrer&quot;&gt;New York post&lt;/a&gt;, the ocean (which accounts for 90% of the earth's warming budget) is warming at a rate of around 5 Hiroshimas a second, which would suggest that the &lt;strong&gt;total heat from the bushfires would be eclipsed by global warming forcing in around 3 hours&lt;/strong&gt;.&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="56" LastEditDate="2020-02-18T01:18:43.837" LastActivityDate="2020-02-18T01:18:43.837" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="19191" PostTypeId="1" AcceptedAnswerId="19193" CreationDate="2020-02-13T09:08:33.817" Score="14" ViewCount="6385" Body="&lt;p&gt;Waves are mostly caused by &lt;strong&gt;Friction of wind on surface of water&lt;/strong&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Wind blows from &lt;strong&gt;sea to land in day&lt;/strong&gt; and &lt;strong&gt;land to sea in night&lt;/strong&gt; due to pressure and temperature difference.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So it is intuitive why there are waves towards shore in day, but even in night there are waves towards shore. Sometimes even stronger than waves during the day.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is that?&lt;/p&gt;&#xA;" OwnerUserId="18322" LastEditorDisplayName="user1066" LastEditDate="2020-02-13T10:33:29.667" LastActivityDate="2020-02-16T16:17:34.060" Title="Why are there waves in seas towards shore - even in night?" Tags="|meteorology|oceanography|wind|waves|scale|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19192" PostTypeId="2" ParentId="16589" CreationDate="2020-02-13T12:51:20.057" Score="3" Body="&lt;p&gt;I spotted that a scientific paper [1] uses the &amp;quot;lead time&amp;quot; term, and then its definition [2] was found from the Glossary of Meteorology by the American Meteorological Society.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;forecast lead time&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;The length of time between the issuance of a forecast and the&#xA;occurrence of the phenomena that were predicted.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;[1] &lt;a href=&quot;https://link.springer.com/article/10.3103/S106837391405001X&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://link.springer.com/article/10.3103/S106837391405001X&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;[2] &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Forecast_lead_time&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://glossary.ametsoc.org/wiki/Forecast_lead_time&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15528" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-02-13T12:51:20.057" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19193" PostTypeId="2" ParentId="19191" CreationDate="2020-02-13T12:58:03.540" Score="23" Body="&lt;p&gt;Ocean waves (and also in mediterranean type seas and larger lakes, but on a smaller scale) are generated by two processes:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;locally generated waves (&quot;wind waves&quot;), which follow the direction of the wind;&lt;/li&gt;&#xA;&lt;li&gt;waves generated further out in the sea (i.e. &quot;swell waves&quot;), which do not necessarily follow the direction of the wind.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;During the night, you are probably seeing swell waves. Of course, some wave energy is generated also in the opposite direction by the wind blowing offshore, but one can only &quot;see&quot; these waves further out in the sea if the wind is strong enough (see the definition of &lt;a href=&quot;https://www.britannica.com/science/fetch&quot; rel=&quot;noreferrer&quot;&gt;fetch&lt;/a&gt;). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also check the Figure [1] below for clarification on how swell is generated (the longer period wave energy travels faster than the energy of the shorter period waves, so the initial &quot;random&quot; wave field disintegrates into regular swell). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZFiiQ.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZFiiQ.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Shallow water wave processes like diffraction and refraction will curve the paths of the waves that start reaching the coast and &quot;feeling the bottom&quot;. The waves appear to be heading almost perpendicular when they reach the coast, even if 1 km out to sea they're moving almost parallel to the long distance coast.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How the waves appear at the coast to the observer depends on the direction of the local wind. Generally, if the local wind blows in the same direction as the waves (i.e. onshore wind), the waves appear &quot;mushy&quot; as the wind helps to break the waves (see example &lt;a href=&quot;https://kimasurf.com/blog/wp-content/uploads/2015/01/23012015.jpg&quot; rel=&quot;noreferrer&quot;&gt;image&lt;/a&gt;). If the local wind blows in the opposite direction of the incoming waves (i.e. offshore wind), the waves maintain their shape due to opposing wind and they break later (see example &lt;a href=&quot;https://live.staticflickr.com/3176/3072941457_33c55c22a1_b.jpg&quot; rel=&quot;noreferrer&quot;&gt;image&lt;/a&gt;). These conditions are favourable to surfers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1] Holthuijsen, L. H. Waves in oceanic and coastal waters. Cambridge University press, 2010.&lt;/p&gt;&#xA;" OwnerUserId="18907" LastEditorUserId="18907" LastEditDate="2020-02-14T07:23:17.263" LastActivityDate="2020-02-14T07:23:17.263" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="19194" PostTypeId="1" CreationDate="2020-02-13T15:44:03.350" Score="1" ViewCount="72" Body="&lt;p&gt;Why isn't the acceleration of an object in Earth's gravity related to the object's mass? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please, try to explain this effect without physical formulas, but using only logical formulation.&lt;/p&gt;&#xA;" OwnerUserId="18928" LastEditorUserId="-1" LastEditDate="2020-02-14T07:00:25.207" LastActivityDate="2020-02-14T07:00:25.207" Title="Why isn't the acceleration of an object in Earth's gravity related to the object's mass?" Tags="|gravity|" AnswerCount="1" CommentCount="3" ClosedDate="2020-02-14T15:54:36.870" ContentLicense="CC BY-SA 4.0" />
  <row Id="19195" PostTypeId="1" CreationDate="2020-02-13T16:15:50.017" Score="9" ViewCount="113" Body="&lt;p&gt;The New York Times obituary &lt;a href=&quot;https://www.nytimes.com/2015/10/23/science/earth/robert-m-white-meteorologist-who-revolutionized-weather-forecasts-dies-at-92.html&quot; rel=&quot;noreferrer&quot;&gt;Robert M. White, Who Revolutionized Weather Forecasts, Dies at 92&lt;/a&gt; shows the image below. It looks like it might be a model of the Earth but I can't tell for sure.&lt;/p&gt;&#xA;&lt;p&gt;Can the sphere be identified, and if so, is it related to weather forecasting?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/D6BP7.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/D6BP7.jpg&quot; alt=&quot;Robert White in 1967&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;click for full size&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Robert White in 1967. He led the federal government’s weather agencies through five presidencies in the 1960s and ’70s.Credit...Francis Miller/The LIFE Picture Collection/Getty Images&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Robert M. White, a meteorologist who revolutionized the nation’s weather forecasting system, &lt;strong&gt;was the first to lead the National Oceanic and Atmospheric Administration and warned of climate change long before it was widely recognized&lt;/strong&gt;, died on Oct. 14 (2015) at his home in Chevy Chase, Md. He was 92.&lt;/p&gt;&#xA;&lt;p&gt;[...] &lt;strong&gt;As the chairman of the First World Climate Conference in 1979, Dr. White gave a keynote speech that projected the possible consequences of human-induced warming of the planet. The speech, Dr. Baker said, was a turning point in the effort to promote global awareness of climate change.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-02-13T16:59:38.327" Title="Was this spherical device used in weather forecasting in the 1960's?" Tags="|meteorology|weather-forecasting|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19196" PostTypeId="1" CreationDate="2020-02-13T17:19:35.667" Score="1" ViewCount="225" Body="&lt;p&gt;I am trying to get Gallup to do a scientific poll of published climatologists to greatly strengthen the credibility of the 97% consensus. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This must start with very excellent formal definitions of these two key terms: &quot;published&quot; and &quot;climatologist&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The end result of this process is intended to be an exhaustively comprehensive list of: &quot;published climatologists&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the best process for deriving the definition of these two key terms to maximize the plausibility of their specification? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am shooting to actually directly ask all of the world's published climatologists using a very high quality (comparable to Gallup polls) survey that has only true/false or multiple choice answers. &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;The current best guess of the definition of a published climatologist (based on all the feedback) requires three factors:&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;(1) They must have at least one published paper directly pertaining to climate change. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) This must have been in a peer reviewed academic journal directly related to climatology or meteorology. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(3) They must have a PhD degree in climatology or meteorology. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This will screen out many very well qualified individuals because we cannot afford to have any unqualified individuals in this set. &lt;/p&gt;&#xA;" OwnerUserId="17970" LastEditorUserId="17970" LastEditDate="2020-02-17T22:42:57.953" LastActivityDate="2020-02-17T22:42:57.953" Title="What exactly is a published climatologist?" Tags="|climate-change|climate|climatology|" AnswerCount="4" CommentCount="12" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19197" PostTypeId="2" ParentId="19194" CreationDate="2020-02-13T19:19:45.393" Score="3" Body="&lt;p&gt;This is clearly related to &lt;a href=&quot;https://en.wikipedia.org/wiki/Newton%27s_laws_of_motion#Newton&amp;#39;s_second_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Newton's 2nd law&lt;/a&gt;, but since you have asked about the phenomenon rather than the formulas, a &lt;a href=&quot;https://physics.stackexchange.com/a/349423/168121&quot;&gt;Physics SE user explained much better than I can possibly can&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;(..) the gravitational force is different on different masses. Half&#xA;  the mass only has half the weight, so it is also only pulled in half&#xA;  as much by gravity.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;What gravity does is to pull in every single &quot;particle&quot; equally. If&#xA;  there are double as many &quot;particles&quot;, then the pull in each is still&#xA;  the same and each accelerates the same amount.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="18931" LastActivityDate="2020-02-13T19:19:45.393" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19198" PostTypeId="2" ParentId="19196" CreationDate="2020-02-13T19:29:29.203" Score="5" Body="&lt;p&gt;&lt;strong&gt;Regarding Publications&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Published in an accredited scientific journal on climatology would seem to meet the spec. Published on some blog about the weather would seem to fail to meet this spec.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I would agree with this, but respected scientific journals such as &lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Nature_(journal)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nature&lt;/a&gt;&lt;/em&gt; (&lt;a href=&quot;https://www.nature.com/nature/about/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ref 2&lt;/a&gt;) and &lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Scientific_American&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scientific American&lt;/a&gt;&lt;/em&gt; (&lt;a href=&quot;https://www.scientificamerican.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ref 2&lt;/a&gt;) would also meet specification.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Publishing a scientific article/paper is not always straight forward. Sometimes there is an element of &quot;flavor of the month&quot; with some some journals. That may have published papers about a particular aspect of science and now what to publish something else. In such situations an author may have to seek publication in a second or third journal of choice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Regarding the Author&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Two things are import here: the author's qualifications and their publishing history.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A PhD in climatology would meet the spec, A bachelor's degree in meteorology may also seem to meet the spec, how do we decide where to draw the line?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Someone with a PhD may be a specialist in an aspect of a field. A person with a bachelor degree may be a generalist. The author's experience is also import. Someone with a bachelor's degree may have many years of work experience in their field but never bothered to seek higher academic qualifications.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Someone with a history of publishing &quot;quality&quot; papers in respected journals will have greater respect amongst their peers than some who has published very few papers, lesser quality papers or in lesser quality publications.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2020-02-13T19:41:43.100" LastActivityDate="2020-02-13T19:41:43.100" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19199" PostTypeId="2" ParentId="19124" CreationDate="2020-02-13T23:40:29.213" Score="1" Body="&lt;p&gt;I would agree that not all hydro-meteorological hazards are directly related to extreme events if you look at the whole hydrological cycle. In particular, vadose zone and groundwater processes damp out extreme events in the subsurface but can produce hazards. A few examples:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Slope failure induced by saturation of the sediments. The conditions leading to the failure can take years to develop and the failure process can be very slow. For example, recently slope movement above Union Gap in Washington State caused closure of the roads and evacuation of houses until enough data were collected to determine it had stabilized for now&lt;/li&gt;&#xA;&lt;li&gt;Soil salinisation in Australia. When land was cleared for farming the trees were replaced by grasses which lead to greater infiltration and recharge of groundwater. Over years, this caused the watertable to rise to the surface in some places. Since the groundwater is often saline, the result was salt scalds killing the grass, erosion, and higher salt loads in the rivers&lt;/li&gt;&#xA;&lt;li&gt;Groundwater dependent ecosystems get much of their water from the subsurface. Long term changes in the flow system, often exacerbated by pumping or land use change, can cause water table declines that either directly affect the terrestrial ecosystem (eg wetlands) or reduce baseflow to rivers&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;There are also hazards associated with weather events that are not particularly extreme. If it snows, there will be car accidents. The focus on hazards from extreme events is more because they are unusual and tend to affect what events we consider &lt;em&gt;extreme&lt;/em&gt;.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2020-02-13T23:40:29.213" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19200" PostTypeId="2" ParentId="19062" CreationDate="2020-02-13T23:54:35.823" Score="1" Body="&lt;p&gt;Solved&#xA;After more investigation, and help from the PVLIB community, I learned that SWGDN is same as GHI.&lt;/p&gt;&#xA;" OwnerUserId="18376" LastActivityDate="2020-02-13T23:54:35.823" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19201" PostTypeId="2" ParentId="19191" CreationDate="2020-02-14T10:34:35.067" Score="3" Body="&lt;p&gt;I'm making my comment an answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Waves are ubiquitous, except on land ;-). Waves in the open sea are a mix &amp;mdash; a superposition &amp;mdash; of waves in different directions.&lt;sup&gt;1&lt;/sup&gt; The &lt;em&gt;dominating&lt;/em&gt; direction of large waves is, after a while, the wind direction; but that's not absolute. You have some omnidirectional background &quot;noise&quot; of chaotic movement as well as waves which have traveled a long distance and have nothing to do with local conditions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What you see at the shore is the part of the waves on sea which run towards the shore. That's of course less when the wind is off-land, but it is not zero. In addition you have refraction on the coast line; the waves &quot;bend around&quot; the coast line. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In essence, that you see a dominating wave direction towards the land at any wind direction is a result of zero waves emanating from the land.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;hr&gt;&#xA;&lt;sup&gt;1&lt;/sup&gt; In &lt;a href=&quot;https://www.mdpi.com/2073-4433/10/9/562/htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;this study&lt;/a&gt; there is a nice image of the directional spectrum of wind generated waves in &lt;a href=&quot;https://www.mdpi.com/atmosphere/atmosphere-10-00562/article_deploy/html/images/atmosphere-10-00562-g016-550.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Figure 16&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="5396" LastEditorUserId="5396" LastEditDate="2020-02-14T11:44:12.410" LastActivityDate="2020-02-14T11:44:12.410" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="19202" PostTypeId="2" ParentId="9089" CreationDate="2020-02-14T12:06:34.060" Score="3" Body="&lt;p&gt;When a forest is used for sustainable fuel, there is a range of age classes in the forest, some old, some middle aged and so on. Wood harvest takes the oldest trees leaving young trees to take their place. Young trees growing vigorously consume more CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; than the old ones. In such a forest, old trees not used for fuel will decompose over time producing some CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; and a smaller amount of methane. An even smaller amount of carbon will be left in the soil.&lt;/p&gt;&#xA;" OwnerUserId="18934" LastEditorUserId="18081" LastEditDate="2020-02-14T12:20:56.313" LastActivityDate="2020-02-14T12:20:56.313" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19204" PostTypeId="1" CreationDate="2020-02-14T15:56:17.270" Score="3" ViewCount="41" Body="&lt;p&gt;Can you please guide me as to what is the intensity of earth's magnetic and electric fields in different regions of earth.&#xA;Also, specifically in case of hilly or mountainious regions.&lt;/p&gt;&#xA;" OwnerUserId="18939" LastActivityDate="2020-02-14T15:56:17.270" Title="Earth's magnetic and electric field in Hilly Areas" Tags="|earth-observation|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19205" PostTypeId="2" ParentId="19196" CreationDate="2020-02-14T16:14:12.900" Score="6" Body="&lt;p&gt;Not answering the question asked, but the underlying motivation:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The level of consensus hasn't been verified by a poll. The way the 97% figure has been arrived at, AIUI, is by going through every single peer-reviewed and published paper on the topic of anthropogenic climate change and looking at whether says that it does or does not exist, and then assigning these views to the authors of the papers. Why bother with a sampled poll when you already have studies using the entire literature? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want more detail on the methods used, the various studies that came up with the 97% and similar figures are themselves peer-reviewed and published. &lt;a href=&quot;https://iopscience.iop.org/article/10.1088/1748-9326/11/4/048002&quot; rel=&quot;noreferrer&quot;&gt;This&lt;/a&gt; is a review paper looking at them.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2020-02-14T16:14:12.900" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="19207" PostTypeId="2" ParentId="19188" CreationDate="2020-02-14T17:02:36.107" Score="3" Body="&lt;p&gt;Sea water is all very corrosive; the precise composition is not significant. Steel structures are cathodically protected with impressed current and/or sacrificial anodes, usually aluminum. For equipment to be cooled with seawater there are a few choices ;However, for the Navy where reliability is more important than the cost , titanium would be the material of choice ( Type 2 , but types 1 and 3 or the Pt alloy - forgot the number- are also good).The variables for sea water corrosion are : temperature, velocity, sediment, and marine growth, not composition. Inco/Huntington probably evaluated every possibility for sea water corrosion at the La Que labs in Wrightsville Beach NC. Work done before Harvard MBAs' in management eliminated &quot;research&quot; from &quot;research and development&quot;. Papers will be published under &quot;Seahorse Institute&quot; and NACE ( National Association of Corrosion Engineers). NACE will have various current publications available for sea water corrosion ( located in Houston TX). Most of this R &amp;amp; D was done before the internet so it won't be available on-line.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2020-02-14T17:02:36.107" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19209" PostTypeId="2" ParentId="19191" CreationDate="2020-02-15T09:01:31.547" Score="3" Body="&lt;p&gt;&lt;em&gt;Wind blows from sea to land in day and land to sea in night due to pressure and temperature difference.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not so much. This is common in the Mediterranean in summer, for example, where the area sits under a stable area of high pressure and there is little wind caused by the weather system. Go to the Med in winter though, and you'll find the weather systems are completely different as the weather systems which create the Meltemi kick in. If you go elsewhere in the world - Britain, for example - you'll find that the wind at the coast is generally dominated by changeable weather systems blowing across the country, and not by coastal winds. And it should be obvious that you can go somewhere without a coast - say, Kansas - and still experience winds, and see waves on the surface of lakes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other answers have already covered the mechanics of waves better - but I thought this additional misunderstanding in the question was worth clearing up. &lt;/p&gt;&#xA;" OwnerUserId="14995" LastActivityDate="2020-02-15T09:01:31.547" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19210" PostTypeId="1" CreationDate="2020-02-15T09:31:11.130" Score="2" ViewCount="36" Body="&lt;p&gt;If you are viewing the world map on globe, where should you place the center of visible hemisphere so that the maximum land mass is visible. I think this should be somewhere near the &lt;a href=&quot;https://en.wikipedia.org/wiki/Pole_of_inaccessibility#Eurasia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Eurasian point of inaccessibility&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="18949" LastActivityDate="2020-02-15T09:31:11.130" Title="How to orient a globe of the earth so that maximum land mass is visible?" Tags="|continent|" AnswerCount="0" CommentCount="2" ClosedDate="2020-02-24T12:31:29.097" ContentLicense="CC BY-SA 4.0" />
  <row Id="19211" PostTypeId="1" AcceptedAnswerId="19218" CreationDate="2020-02-15T14:13:23.323" Score="2" ViewCount="876" Body="&lt;ol&gt;&#xA;&lt;li&gt;We have one mass extinction that seperates Trias from Jurassic, roughly huge volcanims over a long period of time, and Pangea starting to divide. &lt;/li&gt;&#xA;&lt;li&gt;Another mass extinction that marks the end of Cretaceous period, linked to the fall of an asteroid.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;However there is no mass extinction between the two:&#xA;What are the crucial elements for defining the limit between Jurassic and Cretaceous?&lt;/p&gt;&#xA;" OwnerUserId="18952" LastEditorUserId="18952" LastEditDate="2020-02-16T13:51:55.193" LastActivityDate="2020-02-16T13:51:55.193" Title="What are the key elements defining the separation between Jurassic and Cretaceous?" Tags="|geology|paleontology|stratigraphy|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19212" PostTypeId="1" CreationDate="2020-02-15T16:02:24.957" Score="3" ViewCount="67" Body="&lt;p&gt;I am confused between a Planetary Reflectance and the Relative Spectral Response (RSR). What I know/guess is that RSR is a response/function of an Instrument band's reflectance against a spectral range. Isn't that reflectance the Planetary Reflectance?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am trying to solve this problem: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;If the soil spectra was obtained at 10:20 am in January 5, 2005 at 14°&#xA;  20’ N 121° 13’ E, compute for the spectral radiance of soil at a) sea&#xA;  level, b) extra-terrestrial level. On this day, the Landsat ETM+&#xA;  satellite passed over the area. Neglecting atmospheric effects, what&#xA;  is the possible radiance detected by the sensor in the four bands?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I am given with:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Solar Irradiance values in a) Sea Level and b) Extra-Terrestrial Level which is also a response/function against a range of wavelength.&lt;/li&gt;&#xA;&lt;li&gt;RSR for Landsat-7 ETM+&lt;/li&gt;&#xA;&lt;li&gt;Spectral Signature of soil which is also a reflectance function/response against a spectral range.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Using the reference below, I need to compute for the Spectral Radiance &lt;em&gt;Lλ&lt;/em&gt;.&#xA;I can use the RSR and and Solar Irradiance to compute for Mean Solar Exoatmospheric Irradiance, &lt;em&gt;Esunλ&lt;/em&gt;. The Earth-Sun distance &lt;em&gt;d&lt;/em&gt; has a Julian Calendar table while the Solar zenith angle &lt;em&gt;θs&lt;/em&gt; can be computed using the given date and time in the question. Where can I get the Planetary Reflectance to solve this problem? Is it the reflectance for a wavelength in the RSR?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reference:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://apollomapping.com/wp-content/user_uploads/2011/09/IKONOS_Esun_Calculations.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;IKONOS Planetary Reflectance and Mean Solar Exoatmospheric Irradiance&lt;/a&gt; &lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="18953" LastActivityDate="2020-02-15T16:02:24.957" Title="Planetary Reflectance vs Relative Spectral Response" Tags="|remote-sensing|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19214" PostTypeId="1" CreationDate="2020-02-15T19:30:16.570" Score="3" ViewCount="49" Body="&lt;p&gt;I was reading this on realclimate.org.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question on the below is this. Physics can tell you the radiative forcing of CO&lt;sub&gt;2&lt;/sub&gt;, which is &lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{5.35ln(Cnew/Cpreindustrial)}$&lt;/span&gt;. This tells you how much radiative forcing to expect for an increase of CO&lt;sub&gt;2&lt;/sub&gt; (=&lt;span class=&quot;math-container&quot;&gt;$\small\mathsf{C_{new})}$&lt;/span&gt; over pre-industrial levels (C preindustrial, usually 280 ppm). This formula provides an unambiguous answer of radiative forcing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But... there is a question that then arises about what warming is associated with this particular level of radiative forcing. This &lt;em&gt;appears&lt;/em&gt; to be an empirical matter, looking at past fluctuations of CO&lt;sub&gt;2&lt;/sub&gt; and associated temperatures. This is the climate sensitivity. There are lots of studies on this, with a now-accepted range of 1.5-4.5 °C. But the reason there is some disagreement about this is that it is an empirical question, not so much a physics one, right? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's the realclimate piece:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Blockquote&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As the name suggests, climate sensitivity is an estimate of how sensitive the climate is to an increase in a radiative forcing. The climate sensitivity value tells us how much the planet will warm or cool in response to a given radiative forcing change. As you might guess, the temperature change is proportional to the change in the amount of energy reaching the Earth's surface (the radiative forcing), and the climate sensitivity is the coefficient of proportionality:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;dT = λ*dF&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where 'dT' is the change in the Earth's average surface temperature, 'λ' is the climate sensitivity, usually with units in Kelvin or degrees Celsius per Watts per square meter (°C/[W/m&lt;sup&gt;2&lt;/sup&gt;]), and 'dF' is the radiative forcing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So now to calculate the change in temperature, we just need to know the climate sensitivity. Studies have given a possible range of values of 2-4.5 °C warming for a doubling of CO&lt;sub&gt;2&lt;/sub&gt; (IPCC 2007). Using these values it's a simple task to put the climate sensitivity into the units we need, using the formulas above:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;λ = dT/dF = dT/(5.35 * ln[2])= [2 to 4.5 °C]/3.7 = 0.54 to 1.2 °C/(W/m&lt;sup&gt;2&lt;/sup&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using this range of possible climate sensitivity values, we can plug λ into the formulas above and calculate the expected temperature change. The atmospheric CO&lt;sub&gt;2&lt;/sub&gt; concentration as of 2010 is about 390 ppmv. This gives us the value for 'C', and for 'C&lt;sub&gt;0&lt;/sub&gt;' we'll use the pre-industrial value of 280 ppmv.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;dT = λ*dF = λ * 5.35 * ln(390/280) = 1.8 * λ&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Plugging in our possible climate sensitivity values, this gives us an expected surface temperature change of about 1–2.2 °C of global warming, with a most likely value of 1.4 °C. However, this tells us the equilibrium temperature. In reality it takes a long time to heat up the oceans due to their thermal inertia. For this reason there is currently a planetary energy imbalance, and the surface has only warmed about 0.8 °C. In other words, even if we were to immediately stop adding CO&lt;sub&gt;2&lt;/sub&gt; to the atmosphere, the planet would warm another ~0.6 °C until it reached this new equilibrium state (confirmed by Hansen 2005). This is referred to as the 'warming in the pipeline'.&lt;/p&gt;&#xA;" OwnerUserId="18938" LastEditorUserId="2470" LastEditDate="2020-02-16T12:33:03.660" LastActivityDate="2020-02-16T12:33:03.660" Title="Help in understanding this. Is this just an empirical observation on climate sensitivity?" Tags="|climate-change|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19215" PostTypeId="1" CreationDate="2020-02-15T20:02:03.690" Score="4" ViewCount="45" Body="&lt;p&gt;I have collect several data sets for a small region in Germany called Hessisches Ried (about 90 km²) from different sources for a time period from 2015 to 2019. Daily &lt;a href=&quot;https://www.dwd.de/DE/leistungen/radolan/radolan.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;rainfall amount&lt;/a&gt; &amp;amp; daily evapotranspiration and for irregular time steps &lt;a href=&quot;https://nsidc.org/data/SPL2SMAP_S/versions/2&quot; rel=&quot;nofollow noreferrer&quot;&gt;soil moisture&lt;/a&gt; data from radar satellite imagery. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My goal is to apply an unsupervised classification of at least the soil moisture data (better with all these parameters) to derive a soil property map. The ability to store moisture over time depends mainly on the amount of sand, silt, clay in the soil. So the idea is that different kinds of soil shown different pattern in soil moisture behavior.  But here I am stuck. I can't find any module in python that deals with unsupervised multivariate time series classification or clustering. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data currently stored in a &lt;a href=&quot;http://xarray.pydata.org/en/stable/data-structures.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;xarray&lt;/a&gt; gridded dataset with dimension (latitude, longtitude, time) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What kind of method can you recommend for such a task? Somebody recommends the &lt;a href=&quot;https://s3.amazonaws.com/academia.edu.documents/49455712/s0034-4257_2800_2900144-920161008-28105-gqrac7.pdf?response-content-disposition=inline%3B%20filename%3DEstimation_of_Soil_Physical_Properties_U.pdf&amp;amp;X-Amz-Algorithm=AWS4-HMAC-SHA256&amp;amp;X-Amz-Credential=AKIAIWOWYYGZ2Y53UL3A%2F20200215%2Fus-east-1%2Fs3%2Faws4_request&amp;amp;X-Amz-Date=20200215T093547Z&amp;amp;X-Amz-Expires=3600&amp;amp;X-Amz-SignedHeaders=host&amp;amp;X-Amz-Signature=256bf5348d12274b720d273679993fb38488ba26a9564f6009b6e75809f4195c&quot; rel=&quot;nofollow noreferrer&quot;&gt;SOFM&lt;/a&gt; algorithms - Self organized Feature Mapping. But I am only able to deal with python modules. I don't have the ability to implement such techniques by myself.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT :&lt;/strong&gt;&lt;br&gt;&#xA; I find this module called &lt;a href=&quot;https://tslearn.readthedocs.io/en/latest/variablelength.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;tslearn&lt;/a&gt;. I will try it out and let you know if I am able to do some classification or clustering with it.&lt;/p&gt;&#xA;" OwnerUserId="18950" LastEditorUserId="18950" LastEditDate="2020-02-16T12:49:58.473" LastActivityDate="2020-02-16T12:49:58.473" Title="Which unsupervised classification method for non linear multivariate time series earth observation data in python" Tags="|earth-observation|soil-science|python|soil-moisture|grid-spacing|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19216" PostTypeId="2" ParentId="18964" CreationDate="2020-02-15T20:03:39.793" Score="2" Body="&lt;p&gt;The wording of the question suggests that it is asking about what climate scientists refer to as a run-away feedback. There are, and always have been, positive feed-backs in the climate system, but these are balanced by the major stabilizing effect of emitted infra-red radiation: the simple fact that the Earth emits more heat to space when it is warmer, and this tends to counter-act and heating effect. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hence, our climate behaves like a benign, self-stabilizing system, not one that spirals out of control as soon as it is perturbed. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For instance, a 1 degree Celcius warming will increase the amount of water vapor in the atmosphere by about 6-7% (because hotter air can carry more water -- see, for examnple, &lt;a href=&quot;https://skepticalscience.com/print.php?r=44&quot; rel=&quot;nofollow noreferrer&quot;&gt;skeptical science&lt;/a&gt;). Water vapor is a greenhouse gas, so this extra water vapor will create extra heating of around 2.2 W m-2 (&lt;a href=&quot;https://phys.org/news/2014-03-effect-vapor-climate.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;AGU Report&lt;/a&gt;). At the same time, an extra degree of Celcius means that the Earth is radiating more heat to space. This can be estimated from the Stephan-Boltzman law (maths omitted) and it turns out that 1 degree Celcius of warming results in roughly an additional 6 W m-2 being emitted to space. The extra cooling effect (6 W m-2) is greater than the feedback effect  (2.2 W m-2) so the net effect is that when the Earth's climate is subjected to a temporary warming it will cool back to its equilibrium.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;The reason why we see exponential warming now is not because of a vicious feedback, it is because we are applying an exponentially increasing forcing.&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, there is no absolute physical law which says that the stabilizing effect of emitted infrared radiation always has to win over the feed-backs. There is a concern that rising temperatures might strengthen the feed-backs so much that they overwhelm the stabilizing effects, leading to an unstoppable run-away feedback which could well wipe out all mammals, us included. That would be vicious. It has to be said, of course, that there are no credible predictions of a run-away feedback anytime soon -- the debate there is whether our models would be able to spot one before it happened. &lt;/p&gt;&#xA;" OwnerUserId="17518" LastActivityDate="2020-02-15T20:03:39.793" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19218" PostTypeId="2" ParentId="19211" CreationDate="2020-02-16T02:00:09.317" Score="3" Body="&lt;p&gt;Short answer, there isn't one. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The J-K boundary does not have a well defined fingerprint or marker, because of this it is in flux with different studies constantly offering to tweek or redefine its date based on their own criteria.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/019566719190001S&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/019566719190001S&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://ui.adsabs.harvard.edu/abs/2017EGUGA..1912252L/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://ui.adsabs.harvard.edu/abs/2017EGUGA..1912252L/abstract&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.researchgate.net/publication/236003223_Fixing_a_basal_Berriasian_and_Jurassic-Cretaceous_J-K_boundary-_perhaps_there_is_some_light_at_the_end_of_the_tunnel&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/publication/236003223_Fixing_a_basal_Berriasian_and_Jurassic-Cretaceous_J-K_boundary-_perhaps_there_is_some_light_at_the_end_of_the_tunnel&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2020-02-16T02:00:09.317" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19219" PostTypeId="1" CreationDate="2020-02-16T04:19:17.663" Score="5" ViewCount="291" Body="&lt;p&gt;I'd like help to understand these charts. They are charts of Sea Ice Volume. One is drawn with linear decline, the other has all sorts of curves fitted onto it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XLM80.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XLM80.png&quot; alt=&quot;From PIOMAS site&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GnHfI.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GnHfI.png&quot; alt=&quot;From Wipneus Artische Penguin site&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why do we have these different line fits and which is true ?&lt;/p&gt;&#xA;" OwnerUserId="11238" LastEditorUserId="2470" LastEditDate="2020-02-16T12:43:20.967" LastActivityDate="2020-02-17T17:11:48.893" Title="Is the Arctic sea ice disappearing in a linear or non-linear way?" Tags="|sea-ice|arctic|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19220" PostTypeId="2" ParentId="19211" CreationDate="2020-02-16T05:51:02.263" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;No great extinction or burst of diversity separated the Cretaceous&#xA;  from the Jurassic Period that had preceded it.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;If there are no strong elements, some key feature are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;flower plants&lt;/li&gt;&#xA;&lt;li&gt;diatoms in the oceans&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Perhaps the most important of these events, at least for terrestrial&#xA;  life, was the first appearance of the flowering plants, also called&#xA;  the angiosperms or Anthophyta. First appearing in the Lower Cretaceous&#xA;  around 125 million years ago, the flowering plants first radiated in&#xA;  the middle Cretaceous, about 100 million years ago.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://ucmp.berkeley.edu/mesozoic/cretaceous/cretaceous.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt; article also states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Early angiosperms did not develop shrub- or tree-like morphologies,&#xA;  but by the close of the Cretaceous, a number of forms had evolved that&#xA;  any modern botanist would recognize. The angiosperms thrived in a&#xA;  variety of environments such as areas with damper climates, habitats&#xA;  favored by cycads and cycadeoids, and riparian zones. High southern&#xA;  latitudes were not invaded by angiosperms until the end of the&#xA;  Cretaceous. Ferns dominated open, dry and/or low-nutrient lands.&#xA;  Typical Jurassic vegetation, including conifers, cycads, and other&#xA;  gymnosperms, continued on into the Lower Cretaceous without&#xA;  significant changes. At the beginning of this period, conifer&#xA;  diversity was fairly low in the higher latitudes of the Northern&#xA;  Hemisphere, but by the middle of the period, species diversification&#xA;  was increasing exponentially. Swamps were dominated by conifers and&#xA;  angiosperm dicots.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="18952" LastActivityDate="2020-02-16T05:51:02.263" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19221" PostTypeId="2" ParentId="19219" CreationDate="2020-02-16T06:02:48.377" Score="3" Body="&lt;p&gt;There are no &quot;True&quot; curves in the extent that there is no theory or physical laws that link the number of years with the disappearing of arctic ice. (These several curves are only interpolation models, they give a trend: only additional measure points would give us a more accurate fit.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Based on other variables, we could imagine such a law depending on : CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; concentration in the air + surface with average albedo of ice sheets versus ice-free lands/ocean in arctic areas + average earth temperature. Time also would still have an influence, probably due to the accumulation of energy in matter over time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many parameters that could strongly suggest that the disappearing of arctic sea is non linear. &lt;/p&gt;&#xA;" OwnerUserId="18952" LastEditorUserId="18952" LastEditDate="2020-02-17T17:11:48.893" LastActivityDate="2020-02-17T17:11:48.893" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19222" PostTypeId="2" ParentId="19189" CreationDate="2020-02-16T07:48:53.407" Score="11" Body="&lt;h1&gt;The height of the Himalayas&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Like Keith McClary says in his answer, there really are two factors in creating growing/shrinking mountains.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Mountain_formation&quot; rel=&quot;noreferrer&quot;&gt;Mountains grow&lt;/a&gt; due to various reasons. In the case of the Himalayas it's like you must've seen in the documentary: the collision between the Indian and Eurasian continental plates. The material has to go somewhere and thus goes up (simplifying the geology a bit; I think that concepts like buoyancy these days also give some nuance to the subject, but the general picture stays the same). In the Himalayas, the two plates have moved into each other for at least 2500 km, so that's a lot of ground to move!&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bbgFL.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bbgFL.gif&quot; alt=&quot;mountain_formation&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;If that was the only process at play, there would be &lt;em&gt;way&lt;/em&gt; higher mountains. I couldn't find a corresponding figure for the Himalayas, so consider instead the following present-day profile through Switzerland, running roughly north (left) to south (right).&#xA;&lt;a href=&quot;https://i.stack.imgur.com/WJTGQ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WJTGQ.jpg&quot; alt=&quot;Alps-north-south-profile&quot;&gt;&lt;/a&gt;&#xA;You can see that the present-day Alps are at maximum 4 km high. Compare that against a reconstruction of the geology that &lt;em&gt;should be&lt;/em&gt; present, running along basically the same profile:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/U9V7V.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/U9V7V.jpg&quot; alt=&quot;Alps-full-geology&quot;&gt;&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;You can see that the mountains could be as much as 20 km high! You can appreciate just how much mountain has disappeared, for another very young mountain range! So, the reason that mountains aren't as big as they could/should have been, is that they are cut down by &lt;a href=&quot;https://en.wikipedia.org/wiki/Erosion&quot; rel=&quot;noreferrer&quot;&gt;erosion&lt;/a&gt;. Rain, snow, wind, temperature, all break down mountainous rocks into smaller broken pieces. Those pieces are transported away from the mountains as &lt;em&gt;sediment&lt;/em&gt; in rivers (such as the Yangtze for the Himalayas).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, the height of the Himalayas is very much controlled by the relative size of the two effects: how fast does the mountain range grow, and how fast does erosion break it down again. If the two are in equilibrium, the mountain doesn't shrink or grow. If erosion dominates, the mountain will slowly disappear over time. But in the case of the Himalayas, the mountain building generally outpaced the erosion, leading to the unique heights of the Himalayas. In this case, the speed of the collision is definitely the main factor!&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;The size of the Tibetan Plateau&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/upnIS.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/upnIS.gif&quot; alt=&quot;Himalayas-geology&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/VgIZY.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VgIZY.jpg&quot; alt=&quot;convergence&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now if your question was also about why the Tibetan Plateau is so &lt;em&gt;wide&lt;/em&gt; (rather than the Himalayas so &lt;em&gt;high&lt;/em&gt;), I recommend you read &lt;a href=&quot;https://oak.ucc.nau.edu/wittke/Tibet/Plateau.html&quot; rel=&quot;noreferrer&quot;&gt;https://oak.ucc.nau.edu/wittke/Tibet/Plateau.html&lt;/a&gt; , a very well-written summary of the three main hypotheses:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The speed of the collision has lead to a very step-wise straight faults toppling over each other, rather than folding over, which could lead to very long faulted sections. &quot;&lt;em&gt;Crust is thickened by the faulting and subsequent movement of large masses of rock, which are stacked one on top of another like cordwood.&lt;/em&gt;&quot;&lt;/li&gt;&#xA;&lt;li&gt;When India hit the Eurasian plate it still had a heavy oceanic plate that was going under ('subducting') under the Eurasian plate. Now the oceanic plate has disappeared, and now the continental plate is being pulled underneath the Eurasian plate. &quot;&lt;em&gt;This process is reminiscent of taking a block of ice and pushing it beneath another ice slab, causing the latter to rise upwards. However, it is difficult to imagine how the buoyant Indian crust could be kept deep enough to get far beneath the plateau before bobbing to the surface. Perhaps the great speed at which India is colliding to Eurasia allowed this to happen.&lt;/em&gt;&quot;&lt;/li&gt;&#xA;&lt;li&gt;The last hypothesis is simply that the continental collision puts a lot of heat below the plateau. &quot;&lt;em&gt;Like a hot-air balloon, the heated crust is buoyant and rises with the addition of light granitic material at the bottom of the Eurasian crust increasing the height of the Plateau.&lt;/em&gt;&quot;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;This picture shows all those three hypotheses. 1=distributed shortening, 2=underthrusting, 3=lower crustal flow. In each case, a plateau is formed relatively far away from the actual collision between the two plates.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/fjU4f.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fjU4f.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is likely that, really, all three hypotheses together are at play. As explained on the website, at least the first two hypotheses are thought to be related to the speed of the collision.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, yes, both the height and the width of the Himalayas are thought to be linked to the speed of the collision/relative plate movement!&lt;/p&gt;&#xA;" OwnerUserId="12155" LastEditorUserId="12155" LastEditDate="2020-02-16T16:09:13.737" LastActivityDate="2020-02-16T16:09:13.737" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19223" PostTypeId="2" ParentId="16172" CreationDate="2020-02-16T08:04:47.157" Score="0" Body="&lt;p&gt;To calculate the minimum and maximum relative humidity you will need to measure temperature and specific humidity all through the day (the more often you measure, the more accurate it will be), calculate the value of the relative humidity for every measurement, and then choose the lowest and highest values.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the specific humidity is not changing much (stable weather conditions), you will get the maximum relative humidity when the temperature is lowest and the minimum relative humidity when the temperature is highest. This is because the relative humidity is the specific humidity divided by the saturation humidity, and the saturation humidity increases with increasing temperature following the &lt;a href=&quot;https://en.wikipedia.org/wiki/Clausius%E2%80%93Clapeyron_relation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Clausius-Clapeyron&lt;/a&gt; relationship. Hence, you can get an estimate of the minimum and maximum relative humidity from your measurements: you need to switch  the values and everything will make sense: maximum 80%, minimum 50%.&lt;/p&gt;&#xA;" OwnerUserId="17518" LastActivityDate="2020-02-16T08:04:47.157" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19224" PostTypeId="1" AcceptedAnswerId="19247" CreationDate="2020-02-16T08:11:20.963" Score="5" ViewCount="114" Body="&lt;p&gt;CH&lt;sub&gt;4&lt;/sub&gt; and CO&lt;sub&gt;2&lt;/sub&gt; levels show correlation throughout the Pleistocene:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KDvy9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KDvy9.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://trustyetverify.wordpress.com/2018/04/08/the-good-old-times-when-carbon-dioxide-and-methane-levels-as-well-as-temperatures-were-low/&quot; rel=&quot;nofollow noreferrer&quot;&gt;trustyetverify.wordpress.com&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What are the reasons of this coupling?&lt;/p&gt;&#xA;" OwnerDisplayName="user18590" LastEditorDisplayName="user18590" LastEditDate="2020-02-16T12:26:24.940" LastActivityDate="2020-02-18T22:21:05.850" Title="Why are $\small\sf{CH_4}$ and $\small\sf{CO_2}$ levels coupled during the Pleistocene?" Tags="|earth-history|atmospheric-chemistry|co2|methane|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19225" PostTypeId="2" ParentId="19219" CreationDate="2020-02-16T13:08:02.277" Score="4" Body="&lt;p&gt;The box in the lower left of the bottom chart is key to understanding what is presented. Five attempts of a line of best fit have been presented. From the chart, the linear fit (yellow line) is the least best fit, so the loss of Arctic ice not a linear relationship. The other lines are different modeling scenarios the author has attempted. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When testing for lines of best fit, one is trying to find a mathematical equation that will neatly describe something - in this case Arctic ice loss over time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The other four lines of best fit that were considered were: the exponential curve, Gompertz fit, logarithmic fit and a second order polynomial fit. Visual examination of these curves shows they are very close in describing the data and are close to each other.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The important thing to consider in such curve fits is the value of &lt;em&gt;R&lt;sup&gt;2&lt;/sup&gt;&lt;/em&gt;, sometime denoted as &lt;em&gt;r&lt;sup&gt;2&lt;/sup&gt;&lt;/em&gt;. A value of 1 means a perfect fit and a value of zero means absolutely not fit.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All four curved lines have a fit greater or equal to 0.902. That is a good result.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Gompertz fit has an &lt;em&gt;R&lt;sup&gt;2&lt;/sup&gt;&lt;/em&gt; of 0.917 which is the highest value of the options presented. It means that for the data analyzed and evaluated in this study the Gompertz fit is the one that best describes the data. However, given the closeness of &lt;em&gt;R&lt;sup&gt;2&lt;/sup&gt;&lt;/em&gt; values, the other options also give good results, but not as good as the Gompertz fit.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-02-16T13:08:02.277" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19226" PostTypeId="2" ParentId="19191" CreationDate="2020-02-16T16:17:34.060" Score="0" Body="&lt;p&gt;I am not a wave expert, but i thought waves were caused by the gravitational pull of the  moon and sun ? As the ocean is pulled up and down every night and the bulge from the pull being dragged across the ocean and then released sets the waves in motion and the reason they always go towards the shore is because the mass of the ocean and its shape. Once the waves comes in and then underneath it is cycled back out because the top wave has more mass and is the dominate one. The wind just adds to motion or partially cancels out the motion of the wave depending on its direction. I know this is a old thread but i thought it was very interesting. Here is some citation i found while replying and it seems both gravitational pull and wind both cause the wave direction&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://oceanservice.noaa.gov/facts/wavesinocean.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://oceanservice.noaa.gov/facts/wavesinocean.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18960" LastActivityDate="2020-02-16T16:17:34.060" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19227" PostTypeId="1" AcceptedAnswerId="19228" CreationDate="2020-02-16T19:37:20.563" Score="3" ViewCount="172" Body="&lt;p&gt;I was wondering is the sunlight reaching from the general direction east? I came to this conclusion because the image is so dark on the west side however I am not 100% sure.&lt;a href=&quot;https://i.stack.imgur.com/gPCmO.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gPCmO.jpg&quot; alt=&quot;GOES16 imagery&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18961" LastActivityDate="2020-02-18T19:35:15.263" Title="Is the sunlight on the GOES-16 Imagery reaching from the east?" Tags="|meteorology|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="19228" PostTypeId="2" ParentId="19227" CreationDate="2020-02-16T22:28:29.297" Score="5" Body="&lt;p&gt;Yes. The time stamp says that the image is taken at 13:45Z, which means the sun is overhead in the Eastern Atlantic (&lt;a href=&quot;https://www.timeanddate.com/time/map/&quot; rel=&quot;nofollow noreferrer&quot;&gt;12:45 PM local time in Cabo Verde and the Azores&lt;/a&gt;). In Winnepeg, near the upper arrow, it is 7:45 AM and still in darkness.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Being winter in the NH, places that are more southerly like Louisiana and east Texas in the US have light while places at the same longitude further north do not.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can tell that the image is taken in winter from the south-west to north-east slope of the terminator (i.e. the line separating the light and dark areas, see discussion &lt;a href=&quot;https://en.wikipedia.org/wiki/Season&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="17518" LastEditorUserId="17518" LastEditDate="2020-02-18T19:35:15.263" LastActivityDate="2020-02-18T19:35:15.263" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19229" PostTypeId="1" CreationDate="2020-02-17T05:50:34.957" Score="1" ViewCount="79" Body="&lt;h1&gt;Quantifying climate change mitigation urgency seems to have three aspects:&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;(1) Green House Gas reduction targets required to meet a specific goal such as 2C.&lt;/strong&gt;&lt;br&gt;&#xA;The first guesstimate seems to be zero net emissions by 2050. **&lt;br&gt; &#xA;**Until we actually have fully scalable carbon reduction technology we must assume zero emissions. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;(2) Consequences to human society and the rest of life on Earth of exceeding the 2C goal.&lt;/strong&gt;&lt;br&gt;&#xA;The IPCC estimated impacts to crop yields seems quite significant. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;(3) Estimates of the point of no return (tipping point) from feed back loops:&lt;/strong&gt; &lt;br&gt;How much longer can we wait to begin climate change mitigation action before things such as the melting permafrost make climate change mitigation action infeasible? &lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Hypothetical answers to make the question more clear:&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;(1) If there is a consensus of agreement that we must achieve zero GHG emissions by 2050 this precisely quantifies one key aspect of the degree of urgency. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(2) If there is a consensus of agreement that business as usual for 80 years would probably cause 5C of global heating this is another quantified measure of urgency. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(3) If there is a consensus of agreement that 5C of global heating would very likely cause very significantly increased risk to things such as crop production yet another quantified measure of urgency. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;(4) If we are 50 PPM of CO2 away from a key tipping point feedback loop such that the melting of the permafrost cannot be stopped this would provide another quantified measure of urgency. &lt;/p&gt;&#xA;" OwnerUserId="17970" LastEditorUserId="17970" LastEditDate="2020-02-17T17:23:11.867" LastActivityDate="2020-02-17T17:23:11.867" Title="How can we best objectively quantify climate change mitigation urgency?" Tags="|climate-change|climate|climate-models|climatology|greenhouse-gases|" AnswerCount="0" CommentCount="4" ClosedDate="2020-02-23T17:16:27.217" ContentLicense="CC BY-SA 4.0" />
  <row Id="19230" PostTypeId="1" CreationDate="2020-02-17T11:06:36.697" Score="13" ViewCount="4010" Body="&lt;p&gt;The question &lt;a href=&quot;https://earthscience.stackexchange.com/q/19227/6031&quot;&gt;Is the sunlight on the GOES-16 Imagery reaching from the east?&lt;/a&gt; shows a visible light image and so in the night areas the Earth appears dark and in the day areas the Earth is a bit brighter and the clouds are the brightest.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can have 24 hour imaging of clouds and weather in thermal infrared satellite images. Below is a a thermal infrared image at about mid day in Japan and Australia. I'd expect the tops of the clouds to be cold and the outback to be hot, and yet it's just the opposite!&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The clouds are nearly white&lt;/li&gt;&#xA;&lt;li&gt;Central Australia is nearly black&lt;/li&gt;&#xA;&lt;li&gt;The ocean and all of the Asian continent are dull, almost featureless gray; if there weren't a superimposed outline it might be hard to even tell where the water ends and the land begins in some places.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Why is this? What's going on?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Himawari-8 IR1 image from &lt;a href=&quot;https://www.cwb.gov.tw/V8/E/W/OBS_Sat.html&quot; rel=&quot;noreferrer&quot;&gt;Central Weather Bureau&lt;/a&gt; click for full size&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wm8ih.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wm8ih.jpg&quot; alt=&quot;infrared satellite image from Himawari-8 at about 12:00 PM Taiwan time&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2020-02-17T11:12:33.710" LastActivityDate="2020-02-17T15:06:19.993" Title="Why are the clouds white and Australia black in weather satellite infrared images?" Tags="|meteorology|temperature|clouds|weather-satellites|radiative-transfer|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19231" PostTypeId="2" ParentId="19230" CreationDate="2020-02-17T13:02:13.843" Score="11" Body="&lt;p&gt;It is likely because there is already a conversion from the raw data to the grayscale image posted on the CWB website. From &lt;a href=&quot;https://www.e-education.psu.edu/meteo3/l5_p5.html&quot; rel=&quot;noreferrer&quot;&gt;this online course&lt;/a&gt; (emphasis mine):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;[...] using the mathematics behind the laws of radiation, computers can convert the amount of infrared radiation received by the satellite to a temperature (formally called a &quot;brightness temperature&quot; even though it has nothing to do with how bright an object looks to human eyes). Finally, these temperatures are converted to a shade of gray or white (or a color, as you're about to see), to create an infrared satellite image. &lt;em&gt;Conventionally, lower temperatures are represented by brighter shades of gray and white, while higher temperatures are represented by darker shades of gray&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Note that the images you're probably thinking about, where hot = bright and cold = dark (like the first image on the right in the course), also use an arbitrary color scale called &lt;a href=&quot;https://en.wikipedia.org/wiki/False_color#Pseudocolor&quot; rel=&quot;noreferrer&quot;&gt;pseudo-color&lt;/a&gt;. These colors do not correspond to any physical parameter, they are just a representation of temperature made easy for the human eye.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now I guess the question becomes: Why were these conventions chosen, when they go against each other? This I don't know...&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-02-17T13:02:13.843" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19232" PostTypeId="2" ParentId="19230" CreationDate="2020-02-17T13:48:20.377" Score="12" Body="&lt;p&gt;I had a very similar question in a job interview!  The only difference is that it was an image from SEVIRI on Meteosat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The imager on HIMAWARI is called the Advanced Himawari Imager (AHI).  The &lt;a href=&quot;https://www.data.jma.go.jp/mscweb/en/himawari89/space_segment/spsg_ahi.html&quot; rel=&quot;noreferrer&quot;&gt;AHI IR1 channel&lt;/a&gt; is actually channel 13 with a central wavelength of 10.4 µm, which is in the window region (apparently it's called IR1 in reference to an older satellite).  The clear-sky atmosphere is mostly transparent in this region of the electromagnetic spectrum, so we can see the surface or clouds mostly unobstructed by water vapour, ozone, or other gases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In an infrared image such as this one, high clouds are cold.  Forecasters who look at such images for a living like to see clouds as white.  I'm a physicist and I prefer to map values of high intensity to white, which would make clouds black, but forecasters are the most important users so they get their way.  :)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To display cold areas as white, hot areas must logically be displayed as black.  So what we are seeing in this image:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Central Australia is hot.  This is expected, because it is a hot desert with high emissivity.  &lt;s&gt;The image is apparently taken at 12:00Z, which should be between 20:00 and 22:00 legal standard time in mainland Australia, so it's not long after sunset, when the land is still hot.  Australia should appear less &quot;black&quot; at an image taken 8 hours later.&lt;/s&gt;  The image is apparently taken at 12:00 &quot;local&quot; (140°E) time (03:00 UTC).  It's February and summer in Australia, and the northern hemisphere looks a lot less hot (it's also earlier in the morning there, compared to sunrise).&lt;/li&gt;&#xA;&lt;li&gt;Cloud tops are cold.  This is expected, because they are in the upper troposphere.  Those white clouds are ice clouds.&lt;/li&gt;&#xA;&lt;li&gt;There are grey-ish clouds too with little contrast to the ocean.  Those are lower, liquid clouds, they are warmer.  The lowest clouds may be difficult to identify in infrared images, which is why (for example) night time fog detection from satellites is difficult. &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;(I got the job!)&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2020-02-17T15:06:19.993" LastActivityDate="2020-02-17T15:06:19.993" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19233" PostTypeId="1" AcceptedAnswerId="19234" CreationDate="2020-02-17T14:19:28.877" Score="7" ViewCount="623" Body="&lt;p&gt;I came across a narrow streak of clouds in Asia when playing with Google Earth.&#xA;Does anyone know what that is?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1Dxuz.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1Dxuz.jpg&quot; alt=&quot;The clouds&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18964" LastEditorUserId="6298" LastEditDate="2022-02-06T17:24:28.897" LastActivityDate="2022-02-06T17:24:28.897" Title="What is this narrow band of clouds?" Tags="|clouds|earth-observation|satellites|satellite-oddities|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19234" PostTypeId="2" ParentId="19233" CreationDate="2020-02-17T16:34:34.960" Score="12" Body="&lt;p&gt;Given the weather patterns, it looks like Google Earth is generating those cloud overlays from some recent (i.e., the current day) satellite images.  That line is suspiciously close to the edge of disc line for Meteosat 8, which is located over the equator at 41.5 °E.  &lt;strong&gt;I suspect that it's just an artefact of how they're stitching together the various images from geostationary satellites&lt;/strong&gt;.  The satellite zenith angle and data uncertainty get very large towards the edge of the disc, so most products for forecasting and research are clipped to exclude that region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ga9id.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ga9id.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;Image from EUMETSAT: &lt;a href=&quot;https://eumetview.eumetsat.int/mapviewer/?product=EO:EUM:DAT:MSG:CLM-IODC&quot; rel=&quot;noreferrer&quot;&gt;https://eumetview.eumetsat.int/mapviewer/?product=EO:EUM:DAT:MSG:CLM-IODC&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2020-02-17T16:34:34.960" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19235" PostTypeId="1" CreationDate="2020-02-17T16:58:58.863" Score="3" ViewCount="269" Body="&lt;p&gt;Is there popular open-source project on Earth Model for climate change assessment or global earth simulation ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Best regards,&#xA;Adrien&lt;/p&gt;&#xA;" OwnerUserId="18965" LastActivityDate="2020-02-24T07:43:51.777" Title="Open-source earth model for climate change" Tags="|climate|simulation|" AnswerCount="1" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="19236" PostTypeId="1" CreationDate="2020-02-17T19:27:48.883" Score="4" ViewCount="119" Body="&lt;p&gt;It's very long, I know. But please, don't be discouraged from going through this question if you can help me. The question is at the second to the last paragraph, but you need to read through to understand where I am coming from. Thank you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am currently doing some simulations in digital rock physics (using Comsol Multiphysics software). The compression energy density in the solid can be calculated from &lt;span class=&quot;math-container&quot;&gt;$\frac{1}{2}K\Delta^2$&lt;/span&gt;; where &lt;span class=&quot;math-container&quot;&gt;$\Delta$&lt;/span&gt; is the total dilatation (or fractional change in volume), and &lt;span class=&quot;math-container&quot;&gt;$K$&lt;/span&gt; is the bulk modulus parameter of the solid. When I integrate this equation over the volume of the solid, I get the energy. And when I divide the result by the total volume, I get the energy density. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Naturally, if the total volume is changed, the result of the energy density should remain the same, provided the porosity and the material parameters (like the bulk and shear moduli) are the same for both rock volumes. However, I find that this is not so with my models. I have tried using simple 3D models; e.g. I built concentric spheres having the inner sphere as the fluid region and the outer sphere as the solid region. Then I ran the simulation and compared the energy density result with that of another model, which I set up in the same way, but having a different volume. Mind you, these two models both have the same porosity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question then is, why am I not getting the same result? Is my energy density equation wrong in the first place (although I doubt that, as that has been of old from Hooke's law for isotropic media).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you for your time. And, if you can, please suggest possible solutions I can try in order to fix this. I have tried everything in my knowledge base.&lt;/p&gt;&#xA;" OwnerUserId="18967" LastEditorUserId="18081" LastEditDate="2020-02-18T09:44:56.737" LastActivityDate="2020-02-19T01:56:27.603" Title="Energy Density of Porous Rocks" Tags="|geophysics|models|rocks|simulation|stress|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19237" PostTypeId="2" ParentId="19196" CreationDate="2020-02-17T19:56:47.230" Score="0" Body="&lt;p&gt;Just a few comments:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The 97% consensus might be as low as 90% depending on which paper you look at: &lt;a href=&quot;https://www.theguardian.com/environment/climate-consensus-97-per-cent/2016/apr/13/its-settled-90100-of-climate-experts-agree-on-human-caused-global-warming&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.theguardian.com/environment/climate-consensus-97-per-cent/2016/apr/13/its-settled-90100-of-climate-experts-agree-on-human-caused-global-warming&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The 97% consensus appears to count papers, not authors. Quoting the above (emphasis added):&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Our latest paper was written in response to a critique published by&#xA;  Richard Tol in Environmental Research Letters, commenting on the 2013&#xA;  paper published in the same journal by John Cook, myself, and&#xA;  colleagues finding a 97% consensus on human-caused global warming in&#xA;  the peer-reviewed &lt;strong&gt;literature.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Other portions of the article also support that this number counts papers, not authors.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Some consensus papers consider a paper &quot;pro&quot; AGW if it doesn't explicitly state otherwise in the abstract. Quoting the article above:&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Powell evaluated the percentage of papers that don't explicitly reject&#xA;  human-caused global warming in their abstracts&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Not directly relevant, but if we accept that other scientists have some general understanding of climate, the figure drops to &quot;82% among all Earth scientists&quot;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;In my moderator-deleted answer to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2155/who-are-the-3-in-the-often-cited-97-of-climate-scientists&quot;&gt;Who are the 3% in the often cited &amp;quot;97% of climate scientists&amp;quot;?&lt;/a&gt; (which I realize you can't read), I point out that many of these consensus studies search for words like &quot;global warming&quot; instead of more neutral or opposite words like &quot;global temperature trend&quot;, &quot;global cooling&quot;, &quot;global climate outlook&quot;, etc. Thus, the studies themselves are questionable&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerDisplayName="user967" LastActivityDate="2020-02-17T19:56:47.230" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19238" PostTypeId="1" AcceptedAnswerId="19248" CreationDate="2020-02-17T20:09:31.323" Score="4" ViewCount="243" Body="&lt;p&gt;The oceans have dissolved gases as N&lt;sub&gt;2&lt;/sub&gt; or O&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Henry%27s_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Henry's law&lt;/a&gt; establishes there is an equilibrium between the atmospheric concentration of a gas and its concentration in the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The atmosphere has H&lt;sub&gt;2&lt;/sub&gt;O(g).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there H&lt;sub&gt;2&lt;/sub&gt;O(g) dissolved in the oceans or Henry's law does not apply because the water is also H&lt;sub&gt;2&lt;/sub&gt;O?&lt;/p&gt;&#xA;" OwnerDisplayName="user18590" LastEditorUserId="1242" LastEditDate="2020-02-21T00:06:16.147" LastActivityDate="2020-02-21T00:10:52.383" Title="Have the oceans dissolved water vapour?" Tags="|oceanography|atmospheric-chemistry|" AnswerCount="4" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="19239" PostTypeId="2" ParentId="19196" CreationDate="2020-02-17T22:00:37.150" Score="2" Body="&lt;p&gt;A lot of good points are already made in other  answers, but here's a few more thoughts.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The person must have a PhD in Climatology or Meteorology and have at least one paper directly related to climatology...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Some of the most experienced climate scientists I know (IPCC authors, etc) have either worked in national labs all their careers without getting a PhD, or got PhDs in other subjects (e.g, mathematics, particle physics, chemistry) before moving into climate research.  Your list would need to capture those people too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It would be a lot of work to categorise PhD theses as “climatology” or “not climatology”.  In my experience, universities don’t award PhDs &lt;em&gt;in&lt;/em&gt; a particular subject like they do for bachelor degrees, you’re awarded a more general degree of Doctor of Philosophy for your individual thesis.  That’s a UK perspective, the details almost certainly differ from country to country.  On the other hand, it’s unusual for someone with a climatology-related PhD to have not also published at least one climatology-related journal paper, so a journal search should catch most of these people anyway.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...published in a peer reviewed academic journal of climatology or meteorology.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That’s a reasonable place to start.  Originally you mentioned climatology only and I was going to comment that there would be a lot of devil in the detail of separating meteorology from climatology.  You also mentioned “accredited” journals, but “&lt;a href=&quot;https://mjl.clarivate.com/home&quot; rel=&quot;nofollow noreferrer&quot;&gt;ISI listed&lt;/a&gt;”  is probably a better target.  As pointed out by Fred, you’ll have to include the more generalist journals (e.g., &lt;em&gt;Geophysical Research Letters&lt;/em&gt;) and the less immediately obvious specialist ones (e.g., &lt;em&gt;Global Biogeochemical Cycles&lt;/em&gt;, &lt;em&gt;Global Change Biology&lt;/em&gt;).  You’ll also need to decide things like whether you’re using lead author only or all authors, and whether they need to be actively publishing on climate (in which case, what’s the cut off date for inactive?).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All these subjective decisions will affect the exact list you end up with, and you’ll always be able to add in another journal and get a few more names, but with diminishing returns.  In other words, there isn’t a single definitive list of people.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I’m curious, do you have a rough idea how long you expect this list to be once compiled?&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2020-02-17T22:00:37.150" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19240" PostTypeId="2" ParentId="19124" CreationDate="2020-02-17T22:43:07.577" Score="4" Body="&lt;p&gt;The UN International Strategy for Disaster Reduction gives a good definition of a &quot;hydrometeorological hazard&quot;: &lt;a href=&quot;https://www.unisdr.org/2004/wcdr-dialogue/terminology.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Natural processes or phenomena of atmospheric, hydrological or oceanographic nature, which may cause the loss of life or injury, property damage, social and economic disruption or environmental degradation.&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The IPCC define and &quot;Extreme weather event&quot; as follows: &quot;&lt;a href=&quot;https://archive.ipcc.ch/publications_and_data/ar4/wg1/en/annex1sglossary-e-o.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;An extreme weather event is an event that is rare at a particular place and time of year&lt;/a&gt;&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The debate around extremes is strongly focused on extremes which are of interest to society because of their harmful effect (extreme wind, extreme heat, extreme cold, etc), but the term itself could be interpreted as having a broader meaning. We might, for instance, experience extremes of the surface pressure difference between the Azores and Iceland (a statistic which is studied by climatologist because changes in this statistic have interesting links to weather patterns in Europe) -- but this pressure difference is not usually considered as a hazard. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;An earlier answer by haresfur has given several examples of hydro-meteorological hazards which are not climate extremes. To these I would like to add:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Coastal erosion: this is a continuous process caused by tides and storms. It is hazardous for anyone living in a coastal region;&lt;/li&gt;&#xA;&lt;li&gt;Lightning strikes: thunderstorms always pose a hazard. You could, of course, call every thunderstorm &quot;extreme&quot;, but this is not the common usage. Thunderstorms can be common in a given region, but still be a hazard.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Hence, though the bulk of public and scientific debate occurs at the intersection of extremes and hazards, there can be hazards which are not extreme and extremes which are not hazardous.&lt;/p&gt;&#xA;" OwnerUserId="17518" LastActivityDate="2020-02-17T22:43:07.577" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19241" PostTypeId="1" AcceptedAnswerId="19246" CreationDate="2020-02-18T06:17:04.590" Score="5" ViewCount="148" Body="&lt;p&gt;According to IPCC:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Climate change can be a significant driver of desertification and land&#xA;  degradation and can affect food production, thereby, influencing food&#xA;  security.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Source: &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/07/sr2_background_report_final.pdf&quot; rel=&quot;noreferrer&quot;&gt;IPCC&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My concern is if greenhouse gasses increase the temperature, there is more evaporation, so more clouds, so more rainfall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why does climate change generate desertification instead?&lt;/p&gt;&#xA;" OwnerDisplayName="user18590" LastActivityDate="2020-02-18T22:13:33.580" Title="Why does climate change generate desertification?" Tags="|climate-change|desertification|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19242" PostTypeId="2" ParentId="19224" CreationDate="2020-02-18T08:43:51.107" Score="1" Body="&lt;p&gt;Just a guess, not a specialist on the topic. Pleistocene was characterised by multiple glaciations and interglacial periods. The increase in CO2 concentration and the increase in temperature normally leads to thawing of large ares of permafrost and formation of swamp areas in its place. These swamps release methane in the same way they do today. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously, the reduction in CO2 levels and subsequent drop in temperature would lead to the opposite process of swamps freezing over and release of CH4 in the atmosphere stops.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These charts in the original post make it hard to confirm this, but with better resolution I'd expect CH4 levels to be lagging slightly behind CO2 and temperature graphs. &lt;/p&gt;&#xA;" OwnerUserId="18158" LastActivityDate="2020-02-18T08:43:51.107" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19243" PostTypeId="2" ParentId="19238" CreationDate="2020-02-18T09:24:23.230" Score="2" Body="&lt;p&gt;I'm not a chemist, but I'm prepared to take a punt at the answer:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No, there is no water dissolved in the oceans. The water &lt;em&gt;is&lt;/em&gt; the oceans.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2020-02-18T09:24:23.230" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19244" PostTypeId="2" ParentId="19238" CreationDate="2020-02-18T14:46:52.063" Score="2" Body="&lt;p&gt;The answer to your question is yes and no.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You will not find dissolved H2O in water but water can have dissolved O2 and you can find dissolved hydrogen in water i do not know how common it is in nature but it is possible to dissolve hydrogen in water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And it looks like hydrogenated water is a thing &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydrogen_water&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Hydrogen_water&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6258" LastEditDate="2020-02-18T14:57:16.300" LastActivityDate="2020-02-18T14:57:16.300" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19245" PostTypeId="2" ParentId="19238" CreationDate="2020-02-18T19:23:51.990" Score="7" Body="&lt;p&gt;The answer is no, yes and then, perhaps, no.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;No: water vapour is not &quot;dissolved&quot; in the oceans, rather it becomes part of the oceans through a phase change from vapour to liquid (possibly via an intermediary stage as ice). The process of &quot;dissolving&quot; refers to a substance entering a &quot;solution&quot;, which is defined as stable mixture of two or more substances in which the state of the solution is determined, generally, by the solvent (the liquid water in this case). For example, see the wikipedia article on &quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Solution&quot; rel=&quot;nofollow noreferrer&quot;&gt;solution&lt;/a&gt;&quot;. When water vapour enters the ocean, it is just adding to the volume of liquid water. Water vapour bubbles suspended in the ocean is another issue. When a gas is dissolved in a liquid, it ceases to be a gas. So we do not have &quot;O2 gas&quot; dissolved in the ocean, we have O2, which is a gas in the atmosphere, present in the ocean as a solute.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes: on the other hand, there is continuous exchange of water between the atmosphere and the ocean: sometimes water passes from the atmosphere to the ocean, sometimes the other way around, depending on the weather conditions. This is nothing to do the the process of being &quot;dissolved&quot;, but, if the question is motivated by an interest in the exchange of compounds between the atmosphere and the ocean, this cycling of water between the two, which is described more below, will be of interest.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, perhaps, no: the water vapour in the atmosphere is not in equilibrium with liquid water in the ocean (see &lt;a href=&quot;https://en.wikipedia.org/wiki/Vapor_pressure&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipeadia&lt;/a&gt; foe discussion of equilibrium between liquid and gas phases). Generally speaking, the partial pressure of water vapour above the ocean will be below equilibrium, so there will be an evaporative flux of water from the ocean into the atmosphere. The steady evaporation of water from the surface of the oceans is balanced by precipitation (rain, sleet and snow) out of the atmosphere which falls on the oceans or falls on land and then drains into the oceans (see &lt;a href=&quot;https://www.usgs.gov/special-topic/water-science-school/science/fundamentals-water-cycle?qt-science_center_objects=0#qt-science_center_objects&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Fundamentals of the Water Cycle&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="17518" LastEditorUserId="17518" LastEditDate="2020-02-19T07:58:14.113" LastActivityDate="2020-02-19T07:58:14.113" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19246" PostTypeId="2" ParentId="19241" CreationDate="2020-02-18T22:13:33.580" Score="3" Body="&lt;p&gt;Most arid and semi-arid regions are normally far inland. Often those also have terrain features that don't allow for the moist air to reach, such as mountain ranges, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So now if global temperatures increase, the evaporation in semi-arid regions increase as well, reducing the amount of water available for plants. At the same time moisture coming from the ocean still precipitates as rain before reaching those regions. &lt;/p&gt;&#xA;" OwnerUserId="18158" LastActivityDate="2020-02-18T22:13:33.580" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19247" PostTypeId="2" ParentId="19224" CreationDate="2020-02-18T22:21:05.850" Score="2" Body="&lt;p&gt;This question is addressed in a Nature paper on &quot;&lt;a href=&quot;https://www.nature.com/articles/ncomms14383&quot; rel=&quot;nofollow noreferrer&quot;&gt;Understanding the glacial methane cycle&lt;/a&gt;&quot; (Hopcroft et al. 2017).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There conclusion is that changes in methane concentrations are driven by changes in the biosphere associated with the global temperature changes. The dominant factor is the reduction in methane emissions from wetlands in a colder climate. There is also a reduction in emissions associated with forest fires in the cold phases (colder climate means less forest fires; warmer climate means more forest fires).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that the model used by Hopcroft et al. has the CO2 levels prescribed. In this situation the temperature changes in response to the CO2, and then the methane changes in response to the temperature. &lt;/p&gt;&#xA;" OwnerUserId="17518" LastActivityDate="2020-02-18T22:21:05.850" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19248" PostTypeId="2" ParentId="19238" CreationDate="2020-02-19T01:45:51.140" Score="5" Body="&lt;p&gt;TL;DR: Henry's law describes an ideal linear relationship between the equilibrium amount of a low-concentration solute in a solution and the partial pressure of the solute in the gas phase above the solution. Raoult's Law describes the ideal linear relationship between the concentration of the dominant solvent in a solution and the partial pressure of the solvent in the gas phase above the mixture. Since water is the dominant solvent in the oceans, Henry's law does not apply to it. Any water vapour from the atmosphere that dissolves in the oceans simply adds to the solvent.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Henry's law describes the behaviour of solutes in a pure solvent. I will quote parts of &lt;a href=&quot;https://en.wikipedia.org/wiki/Henry%27s_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;the WikiPedia article you cited&lt;/a&gt; to bring out some relevant points.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Henry's law is a gas law that states that the amount of dissolved gas&#xA;  in a liquid is proportional to its partial pressure above the liquid.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;One point neglected in the article is that it is assumed that the gas phase is an ideal mixture of different gases - that is that they follow the ideal gas law. This is a very good approximation for the earth's atmosphere. For ideal gases, the concentration in solution then is related to the concentration in air by the Henry's law constant. The value of the constant depends on how the equation is written and the concentration units used. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Henry's law has been shown to apply to a wide range of solutes in the&#xA;  limit of infinite dilution (x → 0), including non-volatile substances&#xA;  such as sucrose. In these cases, it is necessary to state the law in&#xA;  terms of chemical potentials. For a solute in an ideal dilute&#xA;  solution, the chemical potential depends only on the concentration.&#xA;  For non-ideal solutions, the activity coefficients of the components&#xA;  must be taken into account&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Henry's law becomes exact at very low concentrations of the solute. At higher concentrations, there is deviation from ideality due to interactions between the dissolved species. This means Henry's law is only used for low-concentration solutes. At the other end, Raoult's law applies. So for H&lt;sub&gt;2&lt;/sub&gt;O in the oceans the water is nearly pure so it behaves as an ideal liquid. In thermodynamic terms the ratio between the water partial pressure at equilibrium in air above the solution (the ocean) and the water partial pressure above pure water times the mole fraction of water in the ocean (the mole fraction is the number of moles of water divided by the total number of moles of the solution - so close to 1 because the ocean is mostly water).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If there was absolutely complete ideal mixing between two solutes, say ethanol and water, then Raoult's law would be followed for all mixtures between the two. This is the same as saying the Henry's law constant would be 1 if the concentrations are given in mole fractions. That is not usually the case and the slope of the linear Henry's law region is different. Here is a figure for ethanol water from a more rigorous answer to a &lt;a href=&quot;https://chemistry.stackexchange.com/questions/89872/what-are-the-key-differences-between-raoult-s-law-and-henry-s-law/90771&quot;&gt;question in chemistry stack exchange&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eylPd.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eylPd.png&quot; alt=&quot;https://chemistry.stackexchange.com/questions/89872/what-are-the-key-differences-between-raoult-s-law-and-henry-s-law/90771&quot;&gt;&lt;/a&gt;  &lt;/p&gt;&#xA;" OwnerUserId="1242" LastEditorUserId="1242" LastEditDate="2020-02-21T00:10:52.383" LastActivityDate="2020-02-21T00:10:52.383" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19249" PostTypeId="2" ParentId="19236" CreationDate="2020-02-19T01:56:27.603" Score="2" Body="&lt;p&gt;Eureka! I and my prof figured it out. We found something interesting - that the energy density actually depends on a number of internal variables, namely, the displacements of the outer and inner walls, and porosity (which we already knew). So, when we specified the outer displacement to always be a fraction of the radius of the outer sphere, that seemed to fix the problem.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks to all who attempted to help me out! :)&lt;/p&gt;&#xA;" OwnerUserId="18967" LastActivityDate="2020-02-19T01:56:27.603" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19250" PostTypeId="1" CreationDate="2020-02-20T04:50:19.583" Score="4" ViewCount="256" Body="&lt;p&gt;In Talley et al.'s &lt;a href=&quot;https://www.sciencedirect.com/book/9780750645522/descriptive-physical-oceanography&quot; rel=&quot;nofollow noreferrer&quot;&gt;Descriptive Physical Oceanography&lt;/a&gt;, figure S7.4, it seems that vertical Eddy diffusivity increases with depth between 0 and 30 degrees latitude. Why is this? I thought that diffusivity increases with increasing temperature, but here the opposite seems to be true.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DcEXC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DcEXC.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18974" LastEditorUserId="6031" LastEditDate="2020-02-21T03:33:42.280" LastActivityDate="2020-04-01T21:19:50.153" Title="Why does vertical diffusivity increase with depth in the ocean?" Tags="|oceanography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19251" PostTypeId="1" AcceptedAnswerId="19254" CreationDate="2020-02-20T09:11:23.110" Score="4" ViewCount="192" Body="&lt;p&gt;CO2, methane and other gases contribute to the greenhouse effect.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But most of the greenhouse effect is caused by water vapour in the atmosphere. There is always a lot average moisture present, but it is limited by precipitation. It causes most of the total greenhouse effect, without it, the surface would just radiate heat away from Earth. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If there were no moisture in the air, that should make the average surface temperature much lower. (It is not physically possible, of course.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;What would that temperature be?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="321" LastActivityDate="2020-02-20T16:54:44.917" Title="What would the average temperature be if there were no greenhouse effect from water vapor?" Tags="|climate-change|temperature|climate-models|solar-terrestrial-physics|insolation|" AnswerCount="1" CommentCount="4" ClosedDate="2020-02-22T09:01:56.523" ContentLicense="CC BY-SA 4.0" />
  <row Id="19252" PostTypeId="1" CreationDate="2020-02-20T10:06:27.070" Score="1" ViewCount="92" Body="&lt;p&gt;What causes the large and very long lasting magma plumes which rise up from the mantle and create a hot spot such as the ones which built the island chains of Hawaii and Galapagos? The volcanic islands erupt in chains when oceanic plate slowly moves over the hot spot in the course of many millions of years, but what causes these magma plumes to rise in the first place, in other words what initiates them, and is their location purely random?&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorDisplayName="user18590" LastEditDate="2020-02-21T13:26:46.983" LastActivityDate="2020-02-21T13:26:46.983" Title="What initiates the plumes which create oceanic hot spots?" Tags="|volcanology|plate-tectonics|mantle-plumes|islands|" AnswerCount="0" CommentCount="2" ClosedDate="2020-02-24T08:36:03.137" ContentLicense="CC BY-SA 4.0" />
  <row Id="19253" PostTypeId="1" CreationDate="2020-02-20T12:44:49.533" Score="3" ViewCount="28" Body="&lt;p&gt;I am currently working with sonic measurements in the wells and there is an observation, that velocities are faster in shales over the deviated parts of the well. So, when the relative dip between the well and bedding is high the velocity in shale is faster than in the case when the relative dip is small.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have found some papers stating the same fact, but majority of them describe how to correct for that. However, I am looking for what is the reason?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it the way the measurement is done? Is it the Snell's law? Fermat's principle or anything else?&lt;/p&gt;&#xA;" OwnerUserId="17651" LastActivityDate="2020-02-20T12:44:49.533" Title="Faster shale velocities in deviated wells" Tags="|geology|rocks|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19254" PostTypeId="2" ParentId="19251" CreationDate="2020-02-20T16:54:44.917" Score="3" Body="&lt;p&gt;As was pointed out in the question comments, there is no way to know what Earth's average temperature would do without water vapor in the atmosphere.  However, we can estimate the effects of the water, and remove them.  What follows is a rough approximation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If there were no greenhouse effect, the average temperature of Earth would be about 0F (-18C) instead of 59F (15C). (&lt;a href=&quot;https://www.giss.nasa.gov/research/briefs/ma_01/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.giss.nasa.gov/research/briefs/ma_01/&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Water vapor roughly doubles the warming caused by carbon dioxide. (&lt;a href=&quot;https://www.nasa.gov/topics/earth/features/vapor_warming.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nasa.gov/topics/earth/features/vapor_warming.html&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore I estimate that without water vapor, the average temperature would be about 30F (-1C). &lt;/p&gt;&#xA;" OwnerUserId="18975" LastActivityDate="2020-02-20T16:54:44.917" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19255" PostTypeId="1" AcceptedAnswerId="19263" CreationDate="2020-02-20T21:38:32.087" Score="4" ViewCount="134" Body="&lt;p&gt;&lt;a href=&quot;http://www.stratigraphy.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;International Commission on Stratigraphy&lt;/a&gt; defines the limits of geological ages and they create this chart:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YuU9Q.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YuU9Q.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Click on image for full view&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Acording to Wikipedia:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The standard stratigraphic nomenclature is a chronostratigraphic&#xA;system based on palaeontological intervals of time defined by&#xA;recognised fossil assemblages.&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Chronostratigraphy&quot; rel=&quot;nofollow noreferrer&quot;&gt;chronostratigraphy, Wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;However, until Cambrian, there are not fossils (except chemical traces of unicells).&lt;/p&gt;&#xA;&lt;p&gt;How are the limits between units defined at Precambrian?&lt;/p&gt;&#xA;" OwnerDisplayName="user18590" LastEditorUserId="-1" LastEditorDisplayName="user18590" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-02-21T12:35:21.683" Title="How are stratigraphic limits defined before the Phanerozoic?" Tags="|geology|stratigraphy|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19258" PostTypeId="1" AcceptedAnswerId="19298" CreationDate="2020-02-21T10:17:08.857" Score="4" ViewCount="125" Body="&lt;p&gt;I need to know to which time the &lt;a href=&quot;https://smap.jpl.nasa.gov/mission/description/&quot; rel=&quot;nofollow noreferrer&quot;&gt;SMAP&lt;/a&gt; Satellite passes over a certain location in the future.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I believe this is called acquisition plan, but I'm not sure. Here for example the sentinel 1 &lt;a href=&quot;https://sentinels.copernicus.eu/web/sentinel/missions/sentinel-1/observation-scenario/archive&quot; rel=&quot;nofollow noreferrer&quot;&gt;acquisition plan&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found this &lt;a href=&quot;https://www.n2yo.com/satellite/?s=40376&quot; rel=&quot;nofollow noreferrer&quot;&gt;web page&lt;/a&gt; where you can track the actual position of SMAP and get a 10day prediction but I need a more official source. &lt;/p&gt;&#xA;" OwnerUserId="18950" LastActivityDate="2020-02-25T00:15:03.377" Title="How to find SMAP Satellite acquisiton plan?" Tags="|satellites|nasa|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19261" PostTypeId="1" AcceptedAnswerId="19291" CreationDate="2020-02-21T11:40:33.940" Score="7" ViewCount="316" Body="&lt;p&gt;In animations that show the location / drift of the continents over the aeons, it seems that the continents (or &lt;a href=&quot;https://en.wikipedia.org/wiki/Craton&quot; rel=&quot;nofollow noreferrer&quot;&gt;cratons?&lt;/a&gt;) are just floating / drifting around, sometimes fusing or splitting, but having almost non-changing cumulative surface area over time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This rises the question how that asymmetry between continents and oceans originally formed.  Of course continental crust is less dense than oceanic crust, and once formed the lighter one would just float around on the denser one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there scientific theories how and when this originally started?  Like in liquid, hot, early Earth, the lighter stuff would just form a less-dense layer covering the whole planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And then?  Was it a smooth process of accumulating / clumping continental stuff over time, and after accumulation they just keep drifting around? Or was it some cataclysmic event like early Earth being hit by a Mars-sized object that formed the Moon, and that impact lead to a since-then persisting asymmetry in continents vs. oceans because some of the layers where ripped off locally?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;note:&lt;/strong&gt; Answers to &lt;a href=&quot;https://earthscience.stackexchange.com/q/7888/6031&quot;&gt;What do continents  &quot;lay&quot; on?&lt;/a&gt; do not answer my question because they don't even mention continent genesis. &lt;/p&gt;&#xA;" OwnerUserId="18920" LastEditorUserId="6031" LastEditDate="2020-02-23T07:15:48.863" LastActivityDate="2020-02-24T02:58:30.970" Title="Where did the continents come from?" Tags="|earth-history|continental-rifting|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19262" PostTypeId="1" CreationDate="2020-02-21T12:25:22.943" Score="7" ViewCount="520" Body="&lt;p&gt;During the Carboniferous, vast deposits of coal (or peat at that time) were created because – as far as I understand – decomposition of wood (&lt;a href=&quot;https://en.wikipedia.org/wiki/Wood-decay_fungus#White_rot&quot; rel=&quot;nofollow noreferrer&quot;&gt;white rot&lt;/a&gt;?) was not yet &quot;invented&quot; at that time.  This means CO&lt;sub&gt;2&lt;/sub&gt; and finally carbon was being removed from the atmosphere by photosynthesis and hence removed from the carbon cycle.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This must have led to a depletion of CO&lt;sub&gt;2&lt;/sub&gt; in the Carboniferous atmosphere because the deposition of peat lasted for quite some time.  And even today &lt;em&gt;with&lt;/em&gt; wood decomposition, in the north summer the levels of CO&lt;sub&gt;2&lt;/sub&gt; are dropping as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Keeling_Curve&quot; rel=&quot;nofollow noreferrer&quot;&gt;Keeling curve&lt;/a&gt; is showing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Was there enough CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere to support peat deposition over such a long time?  Or was there some refuel mechanism like vulcanism or some other process(es)?&lt;/p&gt;&#xA;" OwnerUserId="18920" LastEditorUserId="18920" LastEditDate="2020-05-04T22:13:37.720" LastActivityDate="2020-05-07T03:02:46.397" Title="Where did all the CO₂ come from that was deposited as coal during the Carboniferous?" Tags="|atmosphere|carbon-cycle|paleobotany|coal|paleoclimate|" AnswerCount="4" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="19263" PostTypeId="2" ParentId="19255" CreationDate="2020-02-21T12:35:21.683" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The standard stratigraphic nomenclature is a chronostratigraphic system based on palaeontological intervals of time defined by recognised fossil assemblages.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That's wikipedia for you. This is incorrect. The point of a Global Boundary Stratotype Section and Point (GSSP) is to identify a global boundary with a very specific archetypical example. While a recognizable and global fossil assemblage is preferred, sometimes there are better choices and sometimes such assemblages don't exist.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, the stratigraphic boundary that marks the start of the Cenozoic Era, (and the Paleogene System, Paleocene Series and Danian Stage) is a &lt;a href=&quot;http://www.stratigraphy.org/GSSP/Danian.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;millimeter thick layer of fossil-free clay&lt;/a&gt; near El Kef, Tunisia. This clay layer was laid down about 66 million years ago and can be found in many places around the world. This layer is distinct, unique, and occurs worldwide. That clay layer contains the remnants of the dinosaur killer asteroid.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;How are stratigraphic limits defined before the Phanerozoic?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Getting to point of the question, the &lt;a href=&quot;http://www.stratigraphy.org/GSSP/Ediacaran.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;base of the Ediacaran&lt;/a&gt; &quot;is defined as the base of the Marinoan cap carbonate (Nuccaleena Formation) in the Enorama Creek Section of the central Flinders Ranges, Adelaide Rift Complex, South Australia.&quot; The GSSP is the archetype, but as with that thin layer of red clay, this layer of cap carbonate can be found in many places around the world. That layer of cap carbonate represents when a worldwide glaciation event ended.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All of the International Commission on Stratigraphy boundaries that predate the base of the Ediacaran are currently defined in terms of time called Global Standard Stratigraphic Ages (GSSAs). That's a fancy name for a rather arbitrary point in time.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-02-21T12:35:21.683" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19264" PostTypeId="2" ParentId="19262" CreationDate="2020-02-21T18:45:36.820" Score="-8" Body="&lt;p&gt;The CO2 which formed the Carboniferous coal deposits came from the atmosphere. That's the only place it could have come from. Wood rotting organisms were in existence at the time, but the various vegetable matter which formed coal, mainly wood, formed a kind of peat which preserved it in anoxic and slightly acidic conditions. This is why you get well preserved human bodies thousands of years old in European peat bogs. Tollund Man, from Denmark, and Pete Marsh, from England, are well known examples.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This peat layer from dead trees built up over many centuries to form a peat marsh many metres thick. This was then buried and compressed by sediments and under great pressure over millions of years became coal. Coal and hydrocarbons were not the only things that devoured CO2 in vast quantities. The carbonate rocks, mainly calcium carbonate (limestone) did so too. So yes, there was enough CO2 in the atmosphere to support peat deposition over millions of years, with plenty to spare for limestone deposition as well.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-02-21T18:45:36.820" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="19266" PostTypeId="1" CreationDate="2020-02-22T01:24:59.643" Score="9" ViewCount="879" Body="&lt;p&gt;The announcement &lt;a href=&quot;https://www.arianespace.com/press-release/ariane-5-success-va252/&quot; rel=&quot;noreferrer&quot;&gt;Arianespace orbits two satellites – JCSAT-17 and GEO-KOMPSAT-2B – to support connectivity and environmental monitoring in Asia&lt;/a&gt; mentions &lt;a href=&quot;https://www.wmo-sat.info/oscar/satellites/view/35&quot; rel=&quot;noreferrer&quot;&gt;GEO-KOMPSAT-2B&lt;/a&gt; which hosts the &lt;a href=&quot;https://www.wmo-sat.info/oscar/instruments/view/145&quot; rel=&quot;noreferrer&quot;&gt;Geostationary Environmental Monitoring Spectrometer&lt;/a&gt; or GEMS UV/Vis (300-500 nm) imaging spectrometer for hyperspectral imaging of Earth's atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The instrument's &lt;strong&gt;purpose&lt;/strong&gt; is given as&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Ozone profile and total-column or gross profile of other species. Tracked species: BrO, NO&lt;sub&gt;2&lt;/sub&gt;, O&lt;sub&gt;3&lt;/sub&gt;, OClO, SO&lt;sub&gt;2&lt;/sub&gt; and aerosol&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and its &lt;strong&gt;primary mission objectives&lt;/strong&gt; are listed as&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;BrO Mole Fraction&lt;/li&gt;&#xA;&lt;li&gt;ClO Mole Fraction&lt;/li&gt;&#xA;&lt;li&gt;H&lt;sub&gt;2&lt;/sub&gt;O Mole Fraction&lt;/li&gt;&#xA;&lt;li&gt;HC&lt;sub&gt;3&lt;/sub&gt;Br Mole Fraction&lt;/li&gt;&#xA;&lt;li&gt;HCHO Mole Fraction&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;with the following as other mission objectives&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;HCHO Total Column&lt;/li&gt;&#xA;&lt;li&gt;NO Mole Fraction&lt;/li&gt;&#xA;&lt;li&gt;NO&lt;sub&gt;2&lt;/sub&gt; Total Column&lt;/li&gt;&#xA;&lt;li&gt;NO&lt;sub&gt;2&lt;/sub&gt; Mole Fraction&lt;/li&gt;&#xA;&lt;li&gt;O&lt;sub&gt;3&lt;/sub&gt; Mole Fraction&lt;/li&gt;&#xA;&lt;li&gt;O&lt;sub&gt;3&lt;/sub&gt; Total Column&lt;/li&gt;&#xA;&lt;li&gt;SO&lt;sub&gt;2&lt;/sub&gt; Mole Fraction&lt;/li&gt;&#xA;&lt;li&gt;SO&lt;sub&gt;2&lt;/sub&gt; Total Column&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I think that &quot;Mole fraction&quot; is a relative concentration and &quot;Total column&quot; is absolute? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I see that some of the species listed in the instrument's purpose are not in its primary objectives, but oh well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Why exactly are atmospheric BrO and ClO so important to measure, and measure by satellite, and what is the difference between ClO in the &quot;objectives&quot; and OClO in the &quot;purpose&quot;?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="2470" LastEditDate="2020-02-22T06:18:01.950" LastActivityDate="2020-02-23T18:53:34.397" Title="Why are atmospheric BrO and ClO important to measure by satellite?" Tags="|atmosphere|atmospheric-chemistry|satellites|upper-atmosphere|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19267" PostTypeId="2" ParentId="19266" CreationDate="2020-02-22T06:42:37.143" Score="11" Body="&lt;p&gt;BrO and ClO significantly deplete ozone from the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Researchers at &lt;a href=&quot;https://www.arp.harvard.edu/research/climate-change-atmospheric-chemistry&quot; rel=&quot;noreferrer&quot;&gt;Harvard University&lt;/a&gt; state:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It is a remarkable fact that perhaps the most important observation coupling climate forcing to UV dosage levels at the surface at mid-latitudes is the observation of high (e.g. &gt; 10 ppmv) water vapor and low temperatures (&amp;lt; 210 K) with the simultaneous determination of BrO and ClO in the lower stratosphere at mid-latitudes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Similarly, &lt;a href=&quot;https://science.sciencemag.org/content/266/5184/398.abstract&quot; rel=&quot;noreferrer&quot;&gt;Science magazine&lt;/a&gt; states:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Halogen-radical chemistry was responsible for approximately one-third of the photochemical removal of O&lt;sub&gt;3&lt;/sub&gt;; reactions involving BrO account for one-half of this loss. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/halogen&quot; rel=&quot;noreferrer&quot;&gt;Additonally&lt;/a&gt;,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... where the chlorine and bromine thus released participate in the catalytic destruction of ozone.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://core.ac.uk/display/18454995?source=3&quot; rel=&quot;noreferrer&quot;&gt;Kinetic studies of the BrO plus ClO cross-reaction over the range T=246-314 K&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-02-22T06:42:37.143" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19268" PostTypeId="1" AcceptedAnswerId="19272" CreationDate="2020-02-22T10:07:34.860" Score="4" ViewCount="92" Body="&lt;p&gt;With reference to this image...:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SSP51.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SSP51.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;...from &lt;a href=&quot;https://twitter.com/severeweatherEU/status/1231126515057864704&quot; rel=&quot;nofollow noreferrer&quot;&gt;this recent tweet&lt;/a&gt;, I was wondering to what extent would Mediterranean regions be affected by the large desert areas to its South?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;Affected&quot;, here meaning that there would be higher correlation between temperature measurements between the Sahara and Malta (for example), than Malta and Iceland. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I suppose that measurements are correlated but that this correlation reduces with distance to some lower value (but not zero). The question here is, how quickly does this correlation tend to its lower value and is the distance between the &quot;centroid&quot; (?) of the Sahara desert to points in the Mediterranean short enough so that it can be considered an &quot;influence&quot;?&lt;/p&gt;&#xA;" OwnerUserId="18989" LastActivityDate="2020-02-22T20:47:52.367" Title="Extent of desert area influence in local climate" Tags="|temperature|measurements|correlation|pressure|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="19269" PostTypeId="2" ParentId="19268" CreationDate="2020-02-22T10:40:23.370" Score="-2" Body="&lt;p&gt;The proximity of the Sahara certainly does influence the Mediterranean climate, but how much varies according to which way the wind is blowing. The presence of the Sahara has a warming effect and a desiccating effect. Winds also carry large quantities of dust to the Med and to much more distant places like Latin America. Not often, but it does happen. It isn't all that rare for southerly winds from the Sahara to bring unusually warm temperatures to Britain, and to deposit dust on our motorcars. I live here, so I should know.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-02-22T10:40:23.370" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19270" PostTypeId="1" CreationDate="2020-02-22T12:58:52.453" Score="3" ViewCount="382" Body="&lt;p&gt;So Indian peninsula has v shaped mountain ranges. Western ghats and Eastern ghats as shown in the picture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/c5lF0m.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/c5lF0m.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;During Summer Monsoon, the wind flows from Indian ocean to land mass, and due to Coriolis force it bends right, and hits western ghats almost perpendicularly, and Kerala, Southern most west coast state gets orographic rain in windward side of the Western Ghats. The eastern coast however does not get rainfall, as the winds direction is parallel to eastern ghats. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5qWp5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5qWp5.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was wondering that if theoretically if we build artificial mountains (annotated in red), we should be able to get orographic rains along east coasts? I am not sure how much of the South West monsoon wind flows over the landmass of southern India and how moist it is?, as it is likely the western ghats block them significantly. Where and how can I find and interpret the wind data?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/46fi1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/46fi1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18322" LastEditorUserId="18322" LastEditDate="2020-02-22T17:00:26.613" LastActivityDate="2020-02-22T17:00:26.613" Title="Asian South West Monsoon - Rainfall in South East Coast of India" Tags="|climate|wind|rain|monsoon|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="19271" PostTypeId="2" ParentId="19266" CreationDate="2020-02-22T17:45:26.273" Score="5" Body="&lt;p&gt;&lt;em&gt;pretext:&lt;/em&gt; Seeing this question on the list of network questions caught my interest to the site.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I agree with the arguments put forward in the answer by Fred, gravitating on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Radical_(chemistry)&quot; rel=&quot;noreferrer&quot;&gt;radical&lt;/a&gt; character of halogene oxides listed (e.g., BrO, ClO), where unpaired electrons contribute to reactivity to the specis.  Some of them are created &lt;em&gt;in situ&lt;/em&gt; under light radiation and hence may interfere in the constant generation and decomposition of ozone in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ozone-oxygen_cycle&quot; rel=&quot;noreferrer&quot;&gt;Chapman cycle&lt;/a&gt;.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To expand the picture, there is a large «family» of chlorine oxydes, for some of them the structural formulae are given below (each containing a dot already is a radical in a chemical sense) and &lt;a href=&quot;https://en.wikipedia.org/wiki/Chlorine_oxide&quot; rel=&quot;noreferrer&quot;&gt;individual details&lt;/a&gt; (chlorine oxides), and &lt;a href=&quot;https://en.wikipedia.org/wiki/Bromine_dioxide&quot; rel=&quot;noreferrer&quot;&gt;bromine dioxide&lt;/a&gt; in addition:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Z2kiI.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Z2kiI.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;https://de.wikipedia.org/wiki/Chloroxide&quot; rel=&quot;noreferrer&quot;&gt;image credit&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I would point out that the original listing on OSCAR about GEMS' mission as-such &lt;em&gt;accidentally may&lt;/em&gt; contain errors as it lists &lt;code&gt;HC3Br Mole Fraction&lt;/code&gt;.  For one, there isn't such a compound as a stable one you could store in a bottle like copper sulfate.  Indeed I speculate, in analogy to &lt;a href=&quot;https://en.wikipedia.org/wiki/Chlorofluorocarbon&quot; rel=&quot;noreferrer&quot;&gt;CFCs&lt;/a&gt; like &lt;a href=&quot;https://en.wikipedia.org/wiki/Dichloromethane&quot; rel=&quot;noreferrer&quot;&gt;methylene chloride&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Chloroform&quot; rel=&quot;noreferrer&quot;&gt;chloroform&lt;/a&gt;, their target is &lt;a href=&quot;https://en.wikipedia.org/wiki/Bromoform&quot; rel=&quot;noreferrer&quot;&gt;bromoform&lt;/a&gt;, &lt;span class=&quot;math-container&quot;&gt;$\ce{CHBr3}$&lt;/span&gt; which has natural sources, and is relevant to atmospheric ozone, too.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;side note:&lt;/em&gt;&#xA;Similar to the putative chemical error here, &lt;em&gt;some&lt;/em&gt; elder data entries in crystallographic databases erroneously state a symmetry in &lt;span class=&quot;math-container&quot;&gt;$P1$&lt;/span&gt;. While initially submitted by the authors as &lt;span class=&quot;math-container&quot;&gt;$P\bar{1}$&lt;/span&gt;, the bar sometimes was lost during the processing (mentioned, for example, by Hofman &lt;a href=&quot;https://link.springer.com/chapter/10.1007/978-3-642-04759-6_4&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;), like the first &lt;a href=&quot;https://en.wikipedia.org/wiki/Second-harmonic_generation&quot; rel=&quot;noreferrer&quot;&gt;SHG signal&lt;/a&gt; described by &lt;a href=&quot;https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.7.118&quot; rel=&quot;noreferrer&quot;&gt;Franken &lt;em&gt;et al.&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18990" LastActivityDate="2020-02-22T17:45:26.273" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19272" PostTypeId="2" ParentId="19268" CreationDate="2020-02-22T19:05:58.170" Score="2" Body="&lt;p&gt;The mediterranian do in a way create its own climate and is partly protected from the north saharan desert by the dominating wind direction in the area.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The dominating wind direction is from west and northwest,The wind blows into the saharan desert in the direction of the equator in the winter,This creates the mild winters the mediterranian is known for.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the summer more warm and dry air moves from the north saharan desert and into the mediterranian area,this creates the dry summer climate the mediterranan is known for.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the north saharan desert have the strongest influence on the mediterranian climate in the summer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;you can read about it here &lt;a href=&quot;https://en.wikipedia.org/wiki/Hadley_cell&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Hadley_cell&lt;/a&gt; if you click on the animation you can see how the precipitation changes over the year and thereby also the temparature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and here &lt;a href=&quot;https://en.wikipedia.org/wiki/Mediterranean_climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Mediterranean_climate&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="6258" LastEditDate="2020-02-22T20:47:52.367" LastActivityDate="2020-02-22T20:47:52.367" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19274" PostTypeId="1" CreationDate="2020-02-23T00:57:32.883" Score="4" ViewCount="147" Body="&lt;p&gt;I like to naively think of Earth's natural atmosphere as nitrogen, oxygen, argon, water, carbon dioxide and okay, some nitrogen and sulfur oxides, and again okay, &lt;a href=&quot;https://biology.stackexchange.com/q/80302/27918&quot;&gt;a little hydrogen&lt;/a&gt; and methane from microorganisms. Everything else is pollution and shouldn't be there.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just because I like to naively think that way doesn't meant it's so.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The excellent answers to &lt;a href=&quot;https://earthscience.stackexchange.com/q/19266/6031&quot;&gt;Why are atmospheric BrO and ClO important to measure by satellite?&lt;/a&gt; talk about halogen oxides.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are they a natural component of Earth's atmosphere, purely pollution, or a mixed bag?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2020-02-23T18:29:29.690" Title="Are atmospheric halogen oxides &quot;supposed to be&quot; in the atmosphere? Where do they come from?" Tags="|atmosphere|atmospheric-chemistry|air-pollution|upper-atmosphere|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19275" PostTypeId="1" CreationDate="2020-02-23T04:06:29.717" Score="1" ViewCount="99" Body="&lt;p&gt;I have layer stacked Landsat 8 image, how can I calculate &lt;a href=&quot;https://en.wikipedia.org/wiki/Normalized_difference_water_index&quot; rel=&quot;nofollow noreferrer&quot;&gt;Normalized difference water index&lt;/a&gt; (NDWI) from it? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would have been able to calculate it easily using the raster calculator, if I had the green and NIR bands individually.&lt;/p&gt;&#xA;" OwnerUserId="14152" LastEditorUserId="6031" LastEditDate="2020-02-23T07:09:16.597" LastActivityDate="2020-02-23T07:09:16.597" Title="NDWI from Landsat 8" Tags="|remote-sensing|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19277" PostTypeId="1" CreationDate="2020-02-23T07:36:10.373" Score="2" ViewCount="52" Body="&lt;p&gt;I’ve often thought there were three ways to define the seasons. I’ll use spring as an example. The first are the astronomical seasons, which is what calendars show and in my example would be the date of the spring equinox. The second is the meteorological seasons, which where I live says spring are the months of March, April, and May. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I’ve always said there was a third way to define spring (and other seasons), it’s spring when it starts to look and feel like spring. For example I like to watch for the first crocus or tree buds. While I’m not being precise, is this in general what would be meant by a phenological season?&lt;/p&gt;&#xA;" OwnerUserId="16872" LastEditorUserId="6031" LastEditDate="2020-02-23T11:36:31.203" LastActivityDate="2020-02-23T22:00:03.787" Title="Is this what is meant by a phenological season?" Tags="|meteorology|seasons|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19278" PostTypeId="2" ParentId="19258" CreationDate="2020-02-23T07:55:51.897" Score="3" Body="&lt;p&gt;This is not a satellite acquisition plan, but it may be something to get you started. I've used the Python package &lt;a href=&quot;https://rhodesmill.org/skyfield/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Skyfield&lt;/a&gt; to get the subsatellite point of SMAP based on the most recent &lt;a href=&quot;https://en.wikipedia.org/wiki/Two-line_element_set&quot; rel=&quot;nofollow noreferrer&quot;&gt;two line element set&lt;/a&gt; from &lt;a href=&quot;https://celestrak.org/NORAD/elements/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Celestrak&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Please feel feel free to leave comments with questions if a tweak is needed!&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;I'm not an expert on dates and times in Python, the &lt;code&gt;times&lt;/code&gt; object has several conversion and formatting methods if you want to make a table.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NWC8t.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NWC8t.png&quot; alt=&quot;map of SMAP's subsatellite points on Earth for 24-Feb-2020&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;#!/usr/bin/env python&#xA;# -*- coding: utf-8 -*-&#xA;&#xA;from skyfield.api import Topos, load&#xA;import numpy as np&#xA;import matplotlib.pyplot as plt&#xA;&#xA;# mostly from https://rhodesmill.org/skyfield/earth-satellites.html&#xA;resource_satellites_url = 'https://celestrak.org/NORAD/elements/resource.txt'&#xA;resource_satellites = load.tle(resource_satellites_url)&#xA;SMAP = resource_satellites['SMAP']&#xA;print(SMAP)&#xA;print('epoch of the SMAP TLE found: ', SMAP.epoch.utc_jpl())&#xA;&#xA;ts = load.timescale()&#xA;&#xA;days = ts.now() - SMAP.epoch&#xA;print('{:.3f} days away from epoch'.format(days))&#xA;&#xA;# still from that example:&#xA;bluffton = Topos('40.8939 N', '83.8917 W')&#xA;t0 = ts.utc(2020, 2, 23)&#xA;t1 = ts.utc(2020, 2, 24)&#xA;t, events = SMAP.find_events(bluffton, t0, t1, altitude_degrees=30.0)&#xA;for ti, event in zip(t, events):&#xA;    name = ('rise above 30°', 'culminate', 'set below 30°')[event]&#xA;    print(ti.utc_jpl(), name)&#xA;&#xA;# WARNING I've hard coded a date here, if you run this later the TLE retrieved&#xA;# will be newer and so will be less accurate. You'd like the TLE you use to be within&#xA;# a few weeks (if not a few days) of your date for best accuracy.&#xA;&#xA;minutes = range(24*60+1)&#xA;times = ts.utc(2020, 2, 24, 0, minutes, 0) # Example; every minute for 24-feb-2020&#xA;&#xA;subsat_pts = SMAP.at(times).subpoint()&#xA;lat, lon = subsat_pts.latitude.degrees, subsat_pts.longitude.degrees&#xA;&#xA;subsat_pts_now = SMAP.at(ts.now()).subpoint()&#xA;lat_now, lon_now = subsat_pts_now.latitude.degrees, subsat_pts_now.longitude.degrees&#xA;&#xA;# fudging around to keep the plot from wrapping arond the Earth &#xA;breakpoints = lon[1:] - lon[:-1] &amp;gt; 10. # for SMAP this means that longitude has wrapped&#xA;lat, lon = lat[:-1], lon[:-1]&#xA;lon[breakpoints] = np.nan&#xA;&#xA;if True:&#xA;    plt.figure()&#xA;    plt.plot(lon, lat)&#xA;    plt.title('SMAP map every minute for 24-feb-2020, dot is for ts.now()')&#xA;    plt.xlabel('longitude (degs)')&#xA;    plt.ylabel('latitude (degs)')&#xA;    plt.plot([lon_now], [lat_now], 'ok') # put a dot for right now&#xA;    plt.show()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2022-09-27T22:28:57.327" LastActivityDate="2020-02-23T07:55:51.897" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19279" PostTypeId="2" ParentId="19274" CreationDate="2020-02-23T09:51:36.187" Score="-4" Body="&lt;p&gt;Bromine and chlorine are very reactive, so are always found as compounds. They are fairly common elements, mainly in the oceans but also in the Earth's crust. Both have industrial uses, and both damage the Earth's ozone layer. They are evaporated from the ocean by strong sunlight in the form of oxides (BrO and ClO), and in trace amounts are natural constituents of the atmosphere. Very small amounts of these atmospheric halogens are anthropogenic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As strong sunlight is the motive force for evaporating these halogens from the sea (and also from salt evaporite deposits on land), most of the troublesome halogens come from tropical or subtropical seas, and a lesser amount from temperate seas. Measures have already been taken to reduce the anthropogenic component, but there seems to be nothing we can do about naturally produced halogen oxides. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the Earth has managed quite well for billions of years despite this problem, which is responsible for the so-called ozone hole over Antarctica, which waxes and wanes, it doesn't seem like something we should worry about unduly, though of course our efforts to reduce the anthropogenic component should continue.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-02-23T09:51:36.187" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19280" PostTypeId="2" ParentId="19274" CreationDate="2020-02-23T14:24:11.693" Score="5" Body="&lt;p&gt;Classifying the presence of halogen oxides in the atmosphere as either natural, pollution or mixed bag, would result in mixed bag.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Natural sources of halogen oxides include the ocean and volcanoes. &lt;a href=&quot;https://ui.adsabs.harvard.edu/abs/2003TrGeo...4...21V/abstract&quot; rel=&quot;noreferrer&quot;&gt;In 1963, Duce et al&lt;/a&gt;, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;showed that bromine, like chlorine, was lost from the sea salt particles&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2018GL079245&quot; rel=&quot;noreferrer&quot;&gt;Volcanoes&lt;/a&gt; are another source of halogen oxides,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Halogens are emitted from volcanoes primarily as hydrogen halides (HCl, HF, HBr, and HI). Upon mixing with the atmosphere, chlorine and bromine species are partially converted to the halogen oxides OClO and BrO.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.pnas.org/content/107/15/6594&quot; rel=&quot;noreferrer&quot;&gt;and&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Traditionally, emissions of volcanoes were regarded to be mainly of importance for the atmospheric sulfur cycle, acid deposition, and stratospheric effects from explosive eruptions. This view changed recently, mainly because of the observation of very high concentrations of bromine oxide, BrO, in the tropospheric, nonexplosive plume of Soufrière Hills, Montserrat. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The Sun is a requirement for the ocean source of &lt;a href=&quot;https://www.nature.com/articles/4531195a&quot; rel=&quot;noreferrer&quot;&gt;halogen oxides&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Salt lakes, such as the &lt;a href=&quot;http://people.atmos.ucla.edu/jochen/publications/Stutz%20et%20al,%202002,%20Atmospheric%20reactive%20chlorine.pdf&quot; rel=&quot;noreferrer&quot;&gt;Great Salt Lake in Utah&lt;/a&gt; are also sources of halogen oxides.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Forest fires can be a source of &lt;a href=&quot;http://www.apis.ac.uk/overview/pollutants/overview_halogens.htm&quot; rel=&quot;noreferrer&quot;&gt;fluorine&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pollution sources of halogen oxides includes: steel production, phosphate fertilizer production, burning coal, the manufacture of glass and ceramics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Bromine and chlorine are used in cleaning products which are another source. Fire fighting chemicals such as &lt;a href=&quot;https://www.circonomist.com/general/should-we-reconsider-our-love-for-indestructible-organic-halogen-compounds/&quot; rel=&quot;noreferrer&quot;&gt;PFAS&lt;/a&gt; (PolyFluoroAlkyl Substances) are another source.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-02-23T14:24:11.693" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19281" PostTypeId="1" CreationDate="2020-02-23T15:05:38.067" Score="1" ViewCount="27" Body="&lt;p&gt;The question is the following:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to understand the sources and sinks of greenhouse gases we need to understand their transport, both vertically and horizontally.  It takes _______ time for a gas to travel from Boston to Tokyo, Japan than from Boston to just over the equator.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;with the options being more/less/same. I think the answer should be more since the distance is less (by quite a bit apparently). However, I'm not sure if my reasoning is correct there. &lt;/p&gt;&#xA;" OwnerUserId="18999" LastEditorUserId="18999" LastEditDate="2020-02-23T15:29:45.977" LastActivityDate="2020-02-23T15:29:45.977" Title="Time it takes for a gas to go to the equator" Tags="|greenhouse-gases|transportation|" AnswerCount="0" CommentCount="5" ClosedDate="2020-02-24T15:09:45.320" ContentLicense="CC BY-SA 4.0" />
  <row Id="19283" PostTypeId="1" CreationDate="2020-02-23T16:40:24.230" Score="2" ViewCount="146" Body="&lt;p&gt;One thing that still blows my mind about dinosaurs is the massive timeline.  Relevant to this question are &lt;a href=&quot;https://www.activewild.com/dinosaur-periods/&quot; rel=&quot;nofollow noreferrer&quot;&gt;the time periods&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Triassic Period (252.17 to 201.3 million years ago)&lt;/li&gt;&#xA;&lt;li&gt;Cretaceous Period (145 – 66 million years ago)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Triassic-period dinosaur fossils are 50+ million years older than Cretaceous-period dinosaur fossils.  I would thus predict a massive difference in fossil quality.  However, I'm unsure because perhaps any fossil that's able to last say 1 million years can just as easily last say 100 million years.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question&lt;/strong&gt;: Is there a massive drop in quality of Cretaceous vs. Triassic dinosaur fossils?&lt;/p&gt;&#xA;" OwnerUserId="18754" LastActivityDate="2020-07-26T23:12:17.753" Title="Is there a massive drop in quality of Cretaceous vs. Triassic dinosaur fossils?" Tags="|paleontology|fossils|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19284" PostTypeId="2" ParentId="19274" CreationDate="2020-02-23T18:29:29.690" Score="3" Body="&lt;p&gt;As an expansion of Fred's anwer:&#xA;Some of these oxides in question are well recognized and intentionally used.  Thus&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;some of them are used to desinfect water replacing &lt;em&gt;elementary&lt;/em&gt; chlorine gas. They and their derivatives are not very stable (e.g., &lt;a href=&quot;https://en.wikipedia.org/wiki/Dichlorine_monoxide&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{ClO2}$&lt;/span&gt;&lt;/a&gt;, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Hypochlorous_acid&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{HClO}$&lt;/span&gt;&lt;/a&gt;) because during their decomposition organic matter degrades.  Take, for example, &lt;a href=&quot;https://en.wikipedia.org/wiki/Sodium_hypochlorite&quot; rel=&quot;nofollow noreferrer&quot;&gt;sodium hypochlorite&lt;/a&gt; found in many bleaches which in acidic media decomposes into chlorine gas, then with a stronger oxidizing action than chlorine gas itself.  What is the typical application?  John Doe vents the room where it is used, releasing it to the environment.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, the concentration they are used to desinfect water is kept low in swimming pools or drinking water.  Note their low boiling point (e.g., &lt;span class=&quot;math-container&quot;&gt;$2\,^\circ\mathrm{C}$&lt;/span&gt; for &lt;span class=&quot;math-container&quot;&gt;$\ce{ClO2}$&lt;/span&gt; (&lt;a href=&quot;https://en.wikipedia.org/wiki/Dichlorine_monoxide&quot; rel=&quot;nofollow noreferrer&quot;&gt;reference&lt;/a&gt;)).  Balance the low concentration per litre / per gallon with the volume of water engaged.  (Water treatment, e.g. with UV light &lt;em&gt;instead&lt;/em&gt; often may be an alternative, cf. &lt;a href=&quot;https://www.espwaterproducts.com/understanding-uv/&quot; rel=&quot;nofollow noreferrer&quot;&gt;an example&lt;/a&gt;.)&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Let's not forget &lt;em&gt;large&lt;/em&gt; amounts of wood-based paper is &lt;a href=&quot;https://en.wikipedia.org/wiki/Bleaching_of_wood_pulp&quot; rel=&quot;nofollow noreferrer&quot;&gt;bleached&lt;/a&gt;; basically again chopping organic matter (e.g., lignine) into pieces.  Many print-houses advertise that their paper used either is recycled, or is elemental chlorine free.  But guess what is used instead -- often, again it is chlorine dioxide.  The diagram below depicts the worldwide pulp-production, classifying bleach with chlorine gas (&lt;span class=&quot;math-container&quot;&gt;$\ce{Cl2}$&lt;/span&gt;), using chlorine oxide (ECT), or methods skipping chlorine altogether (TCF).  So again, a large &lt;em&gt;potential&lt;/em&gt; artificial source for &lt;span class=&quot;math-container&quot;&gt;$\ce{ClO2}$&lt;/span&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Zpdxe.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Zpdxe.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(&lt;a href=&quot;https://en.wikipedia.org/wiki/Bleaching_of_wood_pulp#Environmental_considerations&quot; rel=&quot;nofollow noreferrer&quot;&gt;image credit&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="18990" LastActivityDate="2020-02-23T18:29:29.690" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19285" PostTypeId="2" ParentId="19266" CreationDate="2020-02-23T18:53:34.397" Score="3" Body="&lt;p&gt;Regarding the Geostationary Environmental Monitoring Spectrometer (GEMS) itself:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The instrument's purpose is given as&lt;/p&gt;&#xA;  &#xA;  &lt;blockquote&gt;&#xA;    &lt;p&gt;Ozone profile and total-column or gross profile of other species. Tracked species: BrO, NO2, O3, OClO, SO2 and aerosol&lt;/p&gt;&#xA;  &lt;/blockquote&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That is rather inaccurate and misleading. GEMS does not track BrO or OClO (or ClO). It does track ozone, but the target is tropospheric rather than stratospheric ozone. GEMS is a satellite instrument whose primary goal is tropospheric air quality monitoring rather than stratospheric chemistry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I think that &quot;Mole fraction&quot; is a relative concentration and &quot;Total column&quot; is absolute?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Mole fraction is the relative concentration of some atmospheric component as a function of altitude. Converting this relative concentration to an absolute quantity (e.g., number of moles, or mass) and integrating from the bottom of the atmosphere to the top yields the &quot;total column&quot; quantity for that component.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Why are atmospheric BrO and ClO important to measure by satellite?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is the question raised in the title of the question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A large number of halogenated hydrocarbons indirectly contribute to ozone depletion. Those halogenated hydrocarbons by themselves are not ozone-depleting substances. But if those compounds reach the upper stratosphere, sunlight can split a halogen atom off of those components. Split-off fluorine atoms tend to bind rather quickly with hydrogen and form an extremely stable hydrogen fluoride molecule. Fluorine barely registers as an ozone-depleting substance because hydrogen fluoride is so stable. Stratospheric hydrogen fluoride eventually diffuses into the troposphere, where it gets dissolved by water and falls as rain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Split-off chlorine and bromine atoms have a different fate. Hydrogen chloride and hydrogen bromide aren't nearly as stable as is hydrogen fluoride. Chlorine and bromine instead alternate between reservoirs such as HCl and hBr and atomic/oxide forms that catalytically deplete ozone. The key reason it is important to monitor these halogens is that most (about 80%) of the chlorine and almost half (40-50%) of the bromine in the stratosphere is anthropogenic.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;References:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://science.sciencemag.org/content/238/4831/1253.short&quot; rel=&quot;nofollow noreferrer&quot;&gt;Molina, Mario J., et al. &quot;Antarctic stratospheric chemistry of chlorine nitrate, hydrogen chloride, and ice: Release of active chlorine.&quot; Science 238.4831 (1987): 1253-1257.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/92GL00781&quot; rel=&quot;nofollow noreferrer&quot;&gt;Poulet, Gilles, et al. &quot;Role of the BrO+ HO2 reaction in the stratospheric chemistry of bromine.&quot; Geophysical research letters 19.23 (1992): 2305-2308.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.spiedigitallibrary.org/journals/Introducing-the-geostationary-environment-monitoring-spectrometer/volume-12/issue-04/044005/Introducing-the-geostationary-environment-monitoring-spectrometer/10.1117/1.JRS.12.044005.full?webSyncID=9a0ce46e-9e6e-c7a4-9dab-6a0cbad05932&amp;amp;sessionGUID=9ad883c9-d902-bc99-93ce-d268bead49a2&amp;amp;SSO=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Choi, Won Jun, et al. &quot;Introducing the geostationary environment monitoring spectrometer.&quot; Journal of Applied Remote Sensing 12.4 (2018): 044005.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-18-0013.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kim, Jhoon, et al. &quot;New era of air quality monitoring from space: Geostationary Environment Monitoring Spectrometer (GEMS).&quot; Bulletin of the American Meteorological Society 2019 (2019): 00.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In addition to the above scientific articles, there are many web pages on stratospheric chemistry. For example, &lt;a href=&quot;https://personal.ems.psu.edu/~brune/m532/meteo532_ch7_stratospheric_chemistry.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://personal.ems.psu.edu/~brune/m532/meteo532_ch7_stratospheric_chemistry.htm&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-02-23T18:53:34.397" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19286" PostTypeId="1" CreationDate="2020-02-23T19:01:01.053" Score="1" ViewCount="193" Body="&lt;p&gt;It's thought that, shortly after Earth was done being &lt;s&gt;refurbished&lt;/s&gt; resurfaced during the &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Late_Heavy_Bombardment&quot; rel=&quot;nofollow noreferrer&quot;&gt;Late Heavy Bombardment&lt;/a&gt;, life abio-generated almost as soon as it was able to. The short delay led to speculation that: in the right conditions, life arises fairly easily; and, under that assumption, many &quot;lifeforms&quot; arose alongside one another, perhaps some &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Shadow_biosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;subsisting even today&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Earth, to the standards of the lifeform(s) that won out, is pretty hospitable--perhaps because life made it that way, altering the chemical properties of the atmosphere and terrain. Life thrives in nearly every remote nook and cranny of the planet. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there any thinking out there into why abiogenesis may have stopped? Is the process expected/hypothesized to be ongoing concurrently, in the present day? If life came to be so rapidly, why isn't it still coming, especially given Earth's apparent suitability?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;(Perhaps our form of life, by its pervasion and alterations to Earth's condition, truly &quot;won out,&quot; monopolizing on Earthly resources in such a way that bars newcomers from developing to compete and bars us from detecting their remnants, should they exist?)&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="15419" LastActivityDate="2020-03-25T14:48:24.413" Title="Is Earth inhospitable?" Tags="|earth-history|" AnswerCount="2" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="19287" PostTypeId="2" ParentId="19283" CreationDate="2020-02-23T19:19:31.587" Score="1" Body="&lt;p&gt;No, there is no massive difference in fossil quality due to the extra 200 million years or so that the oldest dinosaur fossils have spent in the ground compared to the most recent ones at the end of the Cretaceous. Once fossils are properly fossilised, they remain unchanged unless something happens to the rocks. This could be weathering, which damages or destroys many valuable fossils, including recent ones like hominids, or it could be metamorphism, which damages or destroys them with heat.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have seen a photo of a one-billion-year-old fossil from the late Precambrian of a marine algae reliably dated by the new Rhenium 187 - Osmium 187 method, and it was in an excellent state of preservation. Likewise with fossils preserved in amber, some of which are tens of millions of years old but look as fresh as if they had only died yesterday.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-02-23T19:19:31.587" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19288" PostTypeId="2" ParentId="19286" CreationDate="2020-02-23T20:12:50.717" Score="0" Body="&lt;p&gt;The Earth was friendly to abiogenesis a little over 4 billion years ago because a) it was chemically different and b) there were no predators to consume whatever virus-like life forms were spontaneously generated. The chemistry of the early atmosphere (methane, ammonia, CO2 etc) lent itself to Urey and Miller type experiments on a massive scale, forming various versions of what is known as 'primeval soup' like the residues in Urey and Miller's laboratory flasks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These conditions soon vanished, and don't exist anywhere today so far as we know, but if  they did, the organic molecules generated would be consumed by micro-organisms. One of those first life forms managed to survive, and over the course of billions of years evolved into the countless life forms which we have today and the equally countless life forms which have become extinct along the way.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-02-23T20:12:50.717" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19289" PostTypeId="2" ParentId="19277" CreationDate="2020-02-23T22:00:03.787" Score="1" Body="&lt;p&gt;The seasons used by &lt;a href=&quot;https://en.wikipedia.org/wiki/Indigenous_Australian_seasons&quot; rel=&quot;nofollow noreferrer&quot;&gt;indigenous Australians&lt;/a&gt; could be classified as a &lt;a href=&quot;https://en.wikipedia.org/wiki/Phenology&quot; rel=&quot;nofollow noreferrer&quot;&gt;phenological season system&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Depending on the &quot;home range&quot; of each grouping, the year is divided into three to six seasons which are defined by weather and activity by flora and fauna - ecological knowledge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The CSIRO in Australia has more extensive information about &lt;a href=&quot;https://www.csiro.au/en/Research/Environment/Land-management/Indigenous/Indigenous-calendars/About-the-calendars&quot; rel=&quot;nofollow noreferrer&quot;&gt;indigenous seasons&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.visitvictoria.com/things-to-do/aboriginal-victoria/aboriginal-seasons-of-victoria&quot; rel=&quot;nofollow noreferrer&quot;&gt;indigenous seasons in the State of Victoria&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.abc.net.au/btn/classroom/indigenous-seasons/10522128&quot; rel=&quot;nofollow noreferrer&quot;&gt;A useful video&lt;/a&gt; giving a limited explanation of the some the complexity of the season recognized by different indigenous groups.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://parksaustralia.gov.au/kakadu/discover/nature/seasons/&quot; rel=&quot;nofollow noreferrer&quot;&gt;six seasons&lt;/a&gt; of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Kakadu_National_Park&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kakadu region&lt;/a&gt; and &lt;a href=&quot;https://theconversation.com/explainer-the-seasonal-calendars-of-indigenous-australia-88471&quot; rel=&quot;nofollow noreferrer&quot;&gt;seasonal ‘calendars’ of Indigenous Australia&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-02-23T22:00:03.787" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19290" PostTypeId="1" CreationDate="2020-02-24T01:21:49.047" Score="8" ViewCount="46" Body="&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/c/c8/Spider_in_amber_%281%29.jpg/296px-Spider_in_amber_%281%29.jpg&quot;&gt;&lt;br&gt;&#xA;&lt;sub&gt;Image source: &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/c/c8/Spider_in_amber_%281%29.jpg/296px-Spider_in_amber_%281%29.jpg&quot; rel=&quot;noreferrer&quot;&gt;Wikimedia&lt;/a&gt;.&lt;/sub&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There seems to be a few places in the world where &lt;a href=&quot;https://www.britannica.com/science/amber&quot; rel=&quot;noreferrer&quot;&gt;amber&lt;/a&gt; (fossilized tree resin) can be found in large quantities:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Amber can be found in many places around the world including Northern Myanmar (Burma), Mexico and the Dominican Republic, but 90% of the worlds supply comes from the Baltic Region.&lt;br&gt;&#xA;  &lt;sub&gt;&lt;a href=&quot;https://www.fossilera.com/fossils-for-sale/amber&quot; rel=&quot;noreferrer&quot;&gt;Amber for Sale&lt;/a&gt; (commercial site)&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I'm curious about what aspects of these sites give rise to so much amber, unlike most places in the world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question&lt;/strong&gt;: What geographical features facilitate amber fossilization?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would guess there were certain resin-producing trees in those areas, while in other areas the trees didn't produce (a sufficient amount of) resin.  However, there seems to be more to the story: given that &lt;a href=&quot;https://list-of-birthstones.com/Amber.html&quot; rel=&quot;noreferrer&quot;&gt;exposed amber degrades&lt;/a&gt;, the amber would need to be prevented from degrading.&lt;/p&gt;&#xA;" OwnerUserId="18754" LastActivityDate="2020-02-24T01:21:49.047" Title="What geographical features facilitate amber fossilization?" Tags="|fossils|paleogeography|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19291" PostTypeId="2" ParentId="19261" CreationDate="2020-02-24T02:58:30.970" Score="5" Body="&lt;p&gt;The answer is that we don't know. I could give you a list of all the considerations that go into evaluating that question, but it will probably be incomplete and outdated very soon. There were several important papers &lt;a href=&quot;https://scholar.google.com/scholar?as_ylo=2016&amp;amp;q=growth%20of%20continental%20crust&quot; rel=&quot;noreferrer&quot;&gt;published in the recent years&lt;/a&gt;, including some very readable reviews that you might be interested in (&lt;a href=&quot;https://doi.org/10.1016/j.gsf.2018.02.004&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt; &lt;a href=&quot;https://doi.org/10.1016/j.earscirev.2017.07.013&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt; &lt;a href=&quot;https://doi.org/10.1098/rsta.2017.0403&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;). But, there isn't a consensus. A friend just had a paper accepted in which she shows Yet-Another-Breakthrough™ in this field.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the general idea is that most of the continental lithosphere formed early on (Hadean to Archean) and since then the rate has slowed down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Continental crust forms, as you said, by formation of &quot;lighter stuff&quot;. Melting ultramafic mantle rocks leads to formation of basalt, and further melting of basalt leads to granites (and other related rocks) which are indeed lighter in colour, and also lighter in density so they end up at the top, and then &quot;float&quot; as the continental lithosphere on top of the mantle. The problem is that you can also remelt over and over again the continental lithosphere, recycling the already buoyant rocks and not increasing the net volume of the continents. It's this balance which is unknown. How much lithosphere is &quot;juvenile&quot; (i.e. formed by melting of mantle) and how much is recycled.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To make matters worse, continental lithosphere can also be destroyed. The most obvious case is erosion from the continents which then settles as a thin sedimentary cover on the oceanic crust and then lost to the mantle during subduction. Another process is delamination. Some rocks such as basalt are normally less dense than the mantle rocks. However, when metamorphosed at high pressure to become eclogite, they paradoxically become denser than the mantle, leading to the bottom part of the lithosphere to be &quot;ripped off&quot; and sink down into the mantle, thus destroying the continental lithosphere from the bottom. Here's a nice visualisation of this process:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cNyZS.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cNyZS.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;http://geologylearn.blogspot.com/2016/03/mountain-topography.html&quot; rel=&quot;noreferrer&quot;&gt;Source for the image.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-02-24T02:58:30.970" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19292" PostTypeId="2" ParentId="19119" CreationDate="2020-02-24T03:34:31.497" Score="4" Body="&lt;p&gt;Depends on what exactly you are looking for.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mountains contain material which is much older, some &lt;a href=&quot;https://doi.org/10.1029/2005TC001830&quot; rel=&quot;nofollow noreferrer&quot;&gt;as old as the Permian&lt;/a&gt;. This material is hosted in detrital sandstones, so obviously that area was not a mountain back then.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The deformation of that area, is indeed &lt;a href=&quot;https://doi.org/10.1134/S0016852118060055&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cretaceous&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The early stage of deformations dated as 160 Ma, the main stage dated as from 70 to 90 Ma.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So to answer your question, the mountains formed throughout the entire Cretaceous duration, but mostly in later (younger) times.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-02-24T03:34:31.497" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19293" PostTypeId="2" ParentId="18582" CreationDate="2020-02-24T03:51:18.257" Score="2" Body="&lt;p&gt;The answer to your question is probably the second:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Or do REEs only &lt;em&gt;modify the color&lt;/em&gt; of their fluorescence, but not necessarily cause it?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I will give an example of apatite. Here's a cathodoluminescence (luminescence excited by electrons) energy spectrum of a natural apatite. &lt;a href=&quot;https://doi.org/10.3749/canmin.1800021&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PYzYK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PYzYK.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can see several different rare earths triggering the luminescence, but there's also manganese. Apatites from granites usually have lots of manganese, and very little rare earths. So their luminescence would be dominated by the 2.1 eV range, which would be &lt;a href=&quot;https://www.wolframalpha.com/input/?i=2.1%20eV%20to%20photon%20wavelength&quot; rel=&quot;nofollow noreferrer&quot;&gt;yellow&lt;/a&gt;. In contrast, apatite from REE deposits would be dominated by Ce, giving a &lt;a href=&quot;https://www.wolframalpha.com/input/?i=3.0%20eV%20to%20photon%20wavelength&quot; rel=&quot;nofollow noreferrer&quot;&gt;blue-violet&lt;/a&gt; colour. They will also have lots of Nd, but that does not help us because it's in the infra-red range.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-02-24T03:51:18.257" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19294" PostTypeId="2" ParentId="18927" CreationDate="2020-02-24T04:01:30.843" Score="4" Body="&lt;p&gt;This is because of historical inertia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, you are correct that &quot;mass&quot; is technically more correct than &quot;weight&quot;. However, because these are percentages, it does not matter. There are no units. A rock that has 50 weight% SiO2 also has 50 mass% SiO2, regardless of the planet (i.e. &lt;em&gt;g&lt;/em&gt;) you are in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding using &quot;ma%&quot; - I have never seen it and it would be confusing, especially since &quot;ma&quot; will probably be interpreted as the unit &quot;milliannum&quot; which is weird. Using &quot;mass%&quot; would be better, but &quot;wt%&quot; is only 3 characters compared to 5 so there's the issue of laziness. I have seen papers using &quot;mass%&quot; and that's fine, and I wouldn't object to such usage if I were to review a paper.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That said, geologist often weigh rocks. Yes, the numbers are mass. But the action itself is &quot;weigh&quot;. Go figure.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-02-24T04:01:30.843" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19296" PostTypeId="2" ParentId="4874" CreationDate="2020-02-24T07:21:50.647" Score="5" Body="&lt;p&gt;The Meteorological Institute of the University of Hamburg, Germany, provides and simple model called &lt;a href=&quot;https://www.mi.uni-hamburg.de/en/arbeitsgruppen/theoretische-meteorologie/modelle/plasim.html&quot; rel=&quot;noreferrer&quot;&gt;&lt;strong&gt;&quot;Planet Simulator&quot; (PlaSim)&lt;/strong&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Planet Simulator is mainly made for educational purposes and runs on personal computers. However, it is also parallalized and can be run on HPC clusters. There exists an &lt;a href=&quot;https://www.mi.uni-hamburg.de/en/arbeitsgruppen/theoretische-meteorologie/modelle/sources/psusersguide.pdf&quot; rel=&quot;noreferrer&quot;&gt;Documentation&lt;/a&gt; and the source code is said to be well commented. The whole source code is open source. The programming language is Fortran. One should be able to compile it with &lt;code&gt;gfortran&lt;/code&gt; under Linux.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Planet Simulator offers a GUI (after compiling successfully) to set up da model simulation and run it. There is code for postprocessing included. Thus, there is not need for additional postprocessing software. If you write out the output as &lt;code&gt;netCDF&lt;/code&gt;, which is the quasi-standard output format of climate models, it might be practical to install &lt;a href=&quot;http://meteora.ucsd.edu/~pierce/ncview_home_page.html&quot; rel=&quot;noreferrer&quot;&gt;&lt;code&gt;ncview&lt;/code&gt;&lt;/a&gt; or &lt;a href=&quot;https://www.giss.nasa.gov/tools/panoply/&quot; rel=&quot;noreferrer&quot;&gt;&lt;code&gt;Panoply&lt;/code&gt;&lt;/a&gt; because these are common netCDF viewers with which you can look directly into the output files.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2020-02-24T07:21:50.647" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19297" PostTypeId="2" ParentId="19235" CreationDate="2020-02-24T07:43:51.777" Score="5" Body="&lt;h1&gt;NOAA-GDFL model system for CMIP6&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The &lt;em&gt;Geophysical Fluid Dynamics Laboratory&lt;/em&gt; (GDFL) of the &lt;em&gt;National Oceanic and Atmospheric Administration&lt;/em&gt; (NOAA) uses an coupled open source modeling system for their contribution to CMIP6. CMIP6 is the &lt;em&gt;6th Coupled Model Intercomparion Project&lt;/em&gt; (CMIP6) on which basis the &lt;a href=&quot;https://www.ipcc.ch/assessment-report/ar6/&quot; rel=&quot;noreferrer&quot;&gt;Sixth Assessment Report of the IPCC&lt;/a&gt; (the upcoming report) will be partly based on. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The model system of the GDFL consists of several components that have to be compiled invidually and couled to each other. The ocean is represented by the &lt;a href=&quot;https://github.com/NOAA-GFDL/MOM6&quot; rel=&quot;noreferrer&quot;&gt;Modular Ocean Model v6 (MOM)&lt;/a&gt; and the atmosphere is represented by their &lt;a href=&quot;https://github.com/NOAA-GFDL/AM4&quot; rel=&quot;noreferrer&quot;&gt;Atmosphere Model v4.5 (AM)&lt;/a&gt;. Both models are open source. But, I am not sure under which licence they are published. There are further components needed for the proper climate model system setup. Have a look in &lt;a href=&quot;https://github.com/WCRP-CMIP/CMIP6_CVs/blob/master/CMIP6_experiment_id.json&quot; rel=&quot;noreferrer&quot;&gt;this json file&lt;/a&gt; for possible combinations.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Educational climate model: Planet Simulator&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;This text section was already posted by me as an &lt;a href=&quot;https://earthscience.stackexchange.com/a/19296/5594&quot;&gt;answer&lt;/a&gt; to the question &lt;a href=&quot;https://earthscience.stackexchange.com/q/4874/5594&quot;&gt;Simple Climate Models that Predict Climate Change&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Meteorological Institute of the University of Hamburg, Germany, provides and simple model called &lt;a href=&quot;https://www.mi.uni-hamburg.de/en/arbeitsgruppen/theoretische-meteorologie/modelle/plasim.html&quot; rel=&quot;noreferrer&quot;&gt;&lt;strong&gt;&quot;Planet Simulator&quot; (PlaSim)&lt;/strong&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Planet Simulator is mainly made for educational purposes and runs on personal computers. However, it is also parallalized and can be run on HPC clusters. There exists an &lt;a href=&quot;https://www.mi.uni-hamburg.de/en/arbeitsgruppen/theoretische-meteorologie/modelle/sources/psusersguide.pdf&quot; rel=&quot;noreferrer&quot;&gt;Documentation&lt;/a&gt; and the source code is said to be well commented. The whole source code is open source. The programming language is Fortran. One should be able to compile it with &lt;code&gt;gfortran&lt;/code&gt; under Linux.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Planet Simulator offers a GUI (after compiling successfully) to set up da model simulation and run it. There is code for postprocessing included. Thus, there is not need for additional postprocessing software. If you write out the output as &lt;code&gt;netCDF&lt;/code&gt;, which is the quasi-standard output format of climate models, it might be practical to install &lt;a href=&quot;http://meteora.ucsd.edu/~pierce/ncview_home_page.html&quot; rel=&quot;noreferrer&quot;&gt;&lt;code&gt;ncview&lt;/code&gt;&lt;/a&gt; or &lt;a href=&quot;https://www.giss.nasa.gov/tools/panoply/&quot; rel=&quot;noreferrer&quot;&gt;&lt;code&gt;Panoply&lt;/code&gt;&lt;/a&gt; because these are common netCDF viewers with which you can look directly into the output files.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2020-02-24T07:43:51.777" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19298" PostTypeId="2" ParentId="19258" CreationDate="2020-02-24T08:18:55.977" Score="6" Body="&lt;p&gt;As @gerrit pointed out, the Pytroll project has a couple of package which could be useful.&#xA;To answer your question and get the next overpasses for the next twelve hours above a given location, you can use Pyorbital (&lt;a href=&quot;https://github.com/pytroll/pyorbital&quot; rel=&quot;noreferrer&quot;&gt;https://github.com/pytroll/pyorbital&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;from pyorbital.orbital import Orbital&#xA;from datetime import datetime&#xA;orb = Orbital(&quot;SMAP&quot;)&#xA;orb.get_next_passes(datetime.now(), length=12, lon=16, lat=55, alt=0.05)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;with length in hours, lon and lat in degrees, alt in km. And this will display (at the time of writing this):&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;[(datetime.datetime(2020, 2, 24, 13, 14, 54, 147587),&#xA;  datetime.datetime(2020, 2, 24, 13, 23, 23, 955297),&#xA;  datetime.datetime(2020, 2, 24, 13, 19, 8, 924860)),&#xA; (datetime.datetime(2020, 2, 24, 14, 48, 41, 249324),&#xA;  datetime.datetime(2020, 2, 24, 15, 1, 24, 171709),&#xA;  datetime.datetime(2020, 2, 24, 14, 55, 1, 725148)),&#xA; (datetime.datetime(2020, 2, 24, 16, 25, 14, 798347),&#xA;  datetime.datetime(2020, 2, 24, 16, 39, 0, 109628),&#xA;  datetime.datetime(2020, 2, 24, 16, 32, 5, 434271)),&#xA; (datetime.datetime(2020, 2, 24, 18, 5, 14, 617775),&#xA;  datetime.datetime(2020, 2, 24, 18, 15, 43, 280401),&#xA;  datetime.datetime(2020, 2, 24, 18, 10, 27, 671621))]&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Each tuple is &lt;code&gt;(rise, fall, highest point)&lt;/code&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now we also have the pytroll-schedule package, in case you need to make a full acquisition plan, that will allow you for example to put priorities on satellites:&#xA;&lt;a href=&quot;https://github.com/pytroll/pytroll-schedule&quot; rel=&quot;noreferrer&quot;&gt;https://github.com/pytroll/pytroll-schedule&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="19004" LastActivityDate="2020-02-24T08:18:55.977" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19299" PostTypeId="1" AcceptedAnswerId="19308" CreationDate="2020-02-24T10:42:19.757" Score="3" ViewCount="205" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WiqZo.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WiqZo.jpg&quot; alt=&quot;polished sample of mineral-rich rock&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following image is of polished sample of mineral-rich rock. There are two major portions we can see that is ore minerals and rest the grayish material is &lt;a href=&quot;https://en.wikipedia.org/wiki/Gangue&quot; rel=&quot;nofollow noreferrer&quot;&gt;gangue&lt;/a&gt;. The photo was taken with an ore microscope.&lt;/p&gt;&#xA;" OwnerUserId="13748" LastEditorUserId="6031" LastEditDate="2020-02-24T12:12:21.090" LastActivityDate="2020-02-25T08:22:24.040" Title="What ore minerals are likely to be found in a thin section like this? What can we deduce from the structure?" Tags="|geology|rocks|ore|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19300" PostTypeId="1" CreationDate="2020-02-24T14:07:00.270" Score="3" ViewCount="64" Body="&lt;p&gt;What are the current research areas of Earth Science in which there is no absolute consensus of agreement on something?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the current status of the Raymo &amp;amp; Ruddiman hypothesis that the uplift of the Tibetan Plateau during the Cenozoic cooled the Earth, initiating the Quaternary?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you could suggest areas where there are debates involving different schools of thought which have comparable &quot;strength&quot; to their arguments, that would be great.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kind regards&lt;/p&gt;&#xA;" OwnerUserId="19006" LastActivityDate="2020-02-24T14:07:00.270" Title="Current debates in Earth Science?" Tags="|landscape|" AnswerCount="0" CommentCount="3" ClosedDate="2020-02-24T17:55:58.053" ContentLicense="CC BY-SA 4.0" />
  <row Id="19301" PostTypeId="2" ParentId="18927" CreationDate="2020-02-24T16:37:56.777" Score="2" Body="&lt;p&gt;Conventions, whether set by standards or by common usage, are not always in line with the most intuitive or the &quot;most accurate&quot; approach. Would for example that the electrical engineers would stop writing that current flow is in the direction of motion of positive charges rather than that of electrons, we will all be &quot;more accurate&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As has been noted, the relative values of weight percent are the same as those for mass percent. I would add, this is true whether we are on earth, on the moon, or on Jupiter. Only when we are in a non-inertial frame (no &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; for the conversion), do we have any reason to question the truth of the convention.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The term wt% is used in a diverse number of communities beyond the area of your focus (geology), including especially chemistry, chemical engineering, and materials science/engineering. The term is strongly ingrained in those communities. The convention is only &quot;not accurate&quot; in the sense of corrupting the semantics, not in the sense of corrupting the accuracy of any calculations we do with the numbers. Staying with the convention of wt% will make your reports readable across the larger communities. Indeed, switching to your own preferred convention of ma%, essentially just for the purity of semantics, may cause more confusion or aggravation for others in your own community as well as in the outside communities. They will have to &quot;think twice&quot; to translate the new notation to their own.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Otherwise, you are almost akin to a lone wolf crying in a big forest on this one. Allow the terminology to evolve on its own. Alternatively, become active in professional societies such as IUPAC or ASME or ... where such decisions start to take root to action, make your voice heard, and see what you learn at that level.&lt;/p&gt;&#xA;" OwnerUserId="13534" LastEditorUserId="13534" LastEditDate="2020-02-25T15:00:38.803" LastActivityDate="2020-02-25T15:00:38.803" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19302" PostTypeId="1" CreationDate="2020-02-24T19:07:42.957" Score="4" ViewCount="53" Body="&lt;p&gt;In which well known amber location did trees produce amber for the longest continuous period of time, roughly how long was it, and was it long enough to see signs of evolution at work in any of the species trapped in the amber?&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-02-24T19:07:42.957" Title="Continuous production of amber by trees in one location" Tags="|fossils|evolution|amber|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19303" PostTypeId="1" AcceptedAnswerId="19345" CreationDate="2020-02-25T03:57:02.373" Score="8" ViewCount="804" Body="&lt;p&gt;Reading &lt;a href=&quot;https://gizmodo.com/solar-storms-could-confuse-whales-and-cause-mass-strand-1841891375&quot; rel=&quot;nofollow noreferrer&quot;&gt;Solar Storms Could Confuse Whales and Cause Mass Strandings&lt;/a&gt; and the linked open access paper in Current Biology &lt;a href=&quot;https://www.cell.com/current-biology/fulltext/S0960-9822(20)30028-2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gray whales strand more often on days with increased levels of atmospheric radio-frequency noise&lt;/a&gt; I see that there is a significant correlation between the strandings and certain kinds of electromagnetic disturbances, but not a significant correlation with perturbations of the Earth's &amp;quot;DC&amp;quot; or static geomagnetic field alone.&lt;/p&gt;&#xA;&lt;p&gt;That led me to wonder if the direction of the magnetic field that I would see on a compass or some instrument that averages over seconds or longer would show any significant deflection during a &lt;a href=&quot;https://en.wikipedia.org/wiki/Geomagnetic_storm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geomagnetic storm&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Can there be deflections of say 1 degree or more? Or would I have to use a microscope or put a small mirror on the needle and bounce a laser pointer off of it and on to a wall to see the deflection?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-29T13:59:42.797" LastActivityDate="2020-06-29T13:59:42.797" Title="Does a geomagnetic storm visibly deflect a compass?" Tags="|geomagnetism|solar-terrestrial-physics|electromagnetism|magnetosphere|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19304" PostTypeId="1" CreationDate="2020-02-25T05:02:54.780" Score="26" ViewCount="9614" Body="&lt;p&gt;The Washington Post's &lt;a href=&quot;https://www.washingtonpost.com/weather/2020/02/24/antarctic-heat-wave-melted-20-percent-an-islands-snow-cover-days-caused-melt-ponds-proliferate/&quot; rel=&quot;noreferrer&quot;&gt;Antarctic heat wave melted 20 percent of an island’s snow cover in days, caused melt ponds to proliferate&lt;/a&gt; includes the figure below of meltwater ponds on top of snow/ice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The article is a good read, but my question is one of optics, namely what makes a pond of meltwater (essentially pure water) on top of something so white become so dark? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;It increases sunlight absorption and heating, which in this case is &quot;bad&quot; but what's the physics or phenomena behind this that makes these so dark in the first place?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I understand correctly, even shallow ponds or puddles of water can significantly reduce albedo, increase absorption and induce further melting, sometimes in a &quot;runaway&quot; manner. So I don't think it's bulk absorption by the water or contaminants, I think there's something more interesting going on.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4neoK.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4neoK.jpg&quot; alt=&quot;Washington Post: Melt ponds on the Antarctic Peninsula’s George VI Ice Shelf on Jan. 19, 2020. (NASA)&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Melt ponds on the Antarctic Peninsula’s George VI Ice Shelf on Jan. 19, 2020. (NASA)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2020-02-25T13:46:12.417" LastActivityDate="2020-02-28T12:36:45.660" Title="Antarctic and arctic meltwater is &quot;bad&quot; because it's dark, but why is transparent liquid on white stuff so dark?" Tags="|water|antarctic|ice|arctic|radiative-transfer|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19305" PostTypeId="2" ParentId="19304" CreationDate="2020-02-25T05:32:48.503" Score="38" Body="&lt;p&gt;Water has lowest EM absorption in the blue part of light spectrum and increases rapidly  towards both UV and red parts of spectrum. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0kzJx.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0kzJx.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a result in visible light water is blue. Same goes for the ice as it has very similar absorption spectrum. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;While there is a lot of white in the picture, all of it is a thin snow cover on top of blue ice. Once the snow melts you get a blue water on top of thick layer of transparent blue ice that combined absorb most of the light making ponds looks exceptionally dark. Water would be so much lighter in colour if, for example, instead of transparent ice, you'd have sand on the bottom.&lt;/p&gt;&#xA;" OwnerUserId="18158" LastActivityDate="2020-02-25T05:32:48.503" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="19306" PostTypeId="1" CreationDate="2020-02-25T07:34:08.907" Score="2" ViewCount="101" Body="&lt;p&gt;I am working on a geoengineering/space infrastructure project and part of that includes the possibility of using oxygen mined from the moon (specifically lunar regolith) to cause ballistic objects to spin spreading particles in a loose shield to reflect sunlight. The material would all be collected back on the moon which would intercept the orbit of the material. However, as ozone is just 3 oxygen atoms that connect together in the presence of sunlight, would releasing clouds of oxygen in a way that pushes the clouds together allow the formation of O&lt;span class=&quot;math-container&quot;&gt;$_3$&lt;/span&gt;, even temporarily?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this would work, would O&lt;span class=&quot;math-container&quot;&gt;$_3$&lt;/span&gt; free-floating in very loose clouds in space help deflect solar radiation at all?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is part of a larger project to create targeted shading effects to produce a limited risk effect on the earth like regrowing ice sheets. There are a lot of reasons for people to find this project silly but all the research I have done continues to support it in new and interesting ways and any concerns people have raised so far have theoretical solutions. So please don't take time to simply criticize without providing meaningful feedback.  &lt;/p&gt;&#xA;" OwnerUserId="18851" LastEditorUserId="18081" LastEditDate="2020-02-25T08:21:35.727" LastActivityDate="2020-02-25T13:13:55.887" Title="Can Ozone (O$_3$) form in a vacuum and if so can it deflect solar radiation" Tags="|ozone|geoengineering|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19307" PostTypeId="2" ParentId="19306" CreationDate="2020-02-25T08:18:44.960" Score="-1" Body="&lt;p&gt;I think mining oxygen from the moon in vast quantities would be a very expensive project and would deplete the ice believed to be present in some lunar craters at the poles. This would be better used to provide drinking water for astronauts. Obtaining oxygen by other methods would be even more expensive and difficult.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ballistic objects will spin without the aid of oxygen. A shell is made to spin by the rifling in the barrel of the cannon which fires it, and this would also happen if the cannon was fired on the moon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you could release vast clouds of O2 on the moon, solar radiation would ionise it to O3 just as happens in the upper atmosphere of Earth, but to form a protective barrier which could intercept ultraviolet radiation would require unrealistically large quantities of O2 which could never be obtained. Whether you mean a protective barrier for the moon or an additional protective barrier for the Earth, it is not feasible that enough oxygen could be obtained to give a useful result.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-02-25T08:18:44.960" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19308" PostTypeId="2" ParentId="19299" CreationDate="2020-02-25T08:22:24.040" Score="3" Body="&lt;p&gt;Sulfide ore petrography is reflected light is even harder than transmitted light. Unlike transmitted light, colour is actually a very important characteristic feature. But the perception of colour can vary between different light sources, quality and time since polish, microscope lens, and cameras. Therefore, from an image like that it is extremely challenging to tell what the minerals are.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In my opinion you have two of either chalcopyrite, pyrite, pentlandite, pyrrhotite. It is very hard to tell. My guess would be pyrite (the bright one) and chalcopyrite/pentlandite (the golden one).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In cases like this, as a way to move forward, do one or both of the following:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Have thin sections where you know the identity of the minerals so you can compare with your unknown, on exactly the same analytical conditions.&lt;/li&gt;&#xA;&lt;li&gt;Get access to an EDS-SEM system. I know it's easier said than done, but nowadays these instruments are extremely common in almost every research institution, and once you're experienced it takes literally minutes to identify the minerals.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-02-25T08:22:24.040" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19309" PostTypeId="1" CreationDate="2020-02-25T08:50:16.793" Score="2" ViewCount="60" Body="&lt;p&gt;I'm confused about how increased CO2 concentration in the atmosphere affects the pH of the ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The increase in CO2 concentration means the pH of the ocean will decrease (by several chemical rxns). However, as there is more CO2 in the atmosphere, ocean temperatures will rise meaning the ocean will absorb less CO2, likely increasing the pH of the ocean...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short, the rise in CO2 seems to have two contrasting effects on the pH of the ocean... am I interpreting this correctly? If yes, why is the pH of the ocean forecasted to decrease so much in the future? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For reference, here is the article I read: &lt;a href=&quot;https://www.nature.com/scitable/knowledge/library/ocean-acidification-25822734/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/scitable/knowledge/library/ocean-acidification-25822734/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="19009" LastActivityDate="2020-02-25T08:50:16.793" Title="Ocean Acidification - The effect of CO2 concentration on the pH of the ocean" Tags="|atmosphere|oceanography|carbon-cycle|ecology|" AnswerCount="0" CommentCount="4" ClosedDate="2020-02-26T02:42:28.797" ContentLicense="CC BY-SA 4.0" />
  <row Id="19310" PostTypeId="2" ParentId="19306" CreationDate="2020-02-25T12:10:04.587" Score="8" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;If this would work, would &lt;span class=&quot;math-container&quot;&gt;$O_3$&lt;/span&gt; free-floating in very loose clouds in space help deflect solar radiation at all?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No, for many reasons:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Your cloud will disperse. That's what gases do in vacuum.&lt;/li&gt;&#xA;&lt;li&gt;And then the dispersed cloud will get swept away by &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiation_pressure&quot; rel=&quot;noreferrer&quot;&gt;radiation pressure&lt;/a&gt; and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_wind&quot; rel=&quot;noreferrer&quot;&gt;solar wind&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;So you'll have to be constantly replenishing your loose cloud.&lt;/li&gt;&#xA;&lt;li&gt;There are &lt;a href=&quot;https://ozonewatch.gsfc.nasa.gov/facts/SH.html&quot; rel=&quot;noreferrer&quot;&gt;3 billion metric tons&lt;/a&gt; of ozone in the Earth's atmosphere.&lt;/li&gt;&#xA;&lt;li&gt;Compare that huge quantity with the 380.95 kilograms of lunar rock brought back by the six Apollo missions that landed on the Moon, or the 0.401 kilograms retrieved by Russia's unmanned Luna missions.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The engineering feat you are proposing is more than six orders of magnitude larger than anything humankind has done with regard to space. The Apollo program peak cost was a bit less than 5% of the total US federal budget. A factor of ten (one order of magnitude) larger scope would be far beyond the capabilities of the US government. Even with the entire world pitching in, a two order of magnitude increase would be nearly impossible. A six order of magnitude increase &lt;strong&gt;is&lt;/strong&gt; economically impossible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The worst part: Even if successful, your cloud won't do much. Oxygen in all its forms (atomic oxygen, molecular oxygen, and ozone) is nicely transparent in the frequency range where sunlight is at its peak. Evidence: You can see the stars on a clear night.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-02-25T12:10:04.587" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19311" PostTypeId="2" ParentId="19306" CreationDate="2020-02-25T13:13:55.887" Score="6" Body="&lt;p&gt;How exactly are you planning to mine the lunar regolith for oxygen? The oxygen is chemically bonded to metallic cations and it is &lt;em&gt;very&lt;/em&gt; energy intensive to extract as molecular oxygen. You might as well not block the sunlight and use solar panels as an energy source for the separation of oxygen. Mining in itself is a very dusty endeavour, and given that the Moon's gravity is pretty low, just disturbing the regolith can be enough to agitate some dust to shield from solar radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even then, ozone is highly unstable. It is an oxidiser, and will quickly react by:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{2O_3 -&amp;gt; 3O_2}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To simple molecular oxygen. Why ozone anyway? I really don't understand what you're trying to do here.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-02-25T13:13:55.887" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="19312" PostTypeId="2" ParentId="19304" CreationDate="2020-02-25T15:44:45.543" Score="17" Body="&lt;p&gt;&quot;Transparent&quot; is not the same as &quot;white&quot; : white bodies reflect most of the light while transparent bodies let the light though. Once the light enters into water, it may need to travel a long way before it has a chance to go out, and that long travel path provides more opportunities for absorption.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Water absorbs light by itself much more than snow, but contamination makes the situation even worse. If there's a dirt particle in the snow, it has to be located within the top few centimetres to get any significant energy from sunlight: &lt;a href=&quot;https://www.researchgate.net/publication/260867990_Influence_of_grain_shape_on_light_penetration_in_snow&quot; rel=&quot;noreferrer&quot;&gt;only 20% of light penetrate snow deeper than 5 cm &lt;/a&gt;. In clear water, light penetrates much deeper (&lt;a href=&quot;http://bioaqua.vn/en/light-penetration-in-water/&quot; rel=&quot;noreferrer&quot;&gt;25% of energy at 10 m depth&lt;/a&gt;), so all dirt particles within that volume will readily dissipate heat when exposed to sunlight.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you wonder &lt;em&gt;why&lt;/em&gt; snow is white, consider this: dry snow is a mix of ice (refractive index 1.31) and air (refractive index 1), so there's a lot of possible angles at which light will be reflected from the boundary (partially or totally), and a lot of boundaries as well. Wet snow is a mix of ice (refractive index 1.31) and water (refractive index 1.33), so those boundaries barely affect passing light. Solid ice or water have a single boundary with air and no internal boundaries at all.&lt;/p&gt;&#xA;" OwnerUserId="6715" LastEditorUserId="5416" LastEditDate="2020-02-27T10:58:57.393" LastActivityDate="2020-02-27T10:58:57.393" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19313" PostTypeId="2" ParentId="18927" CreationDate="2020-02-25T16:26:11.540" Score="0" Body="&lt;p&gt;(I'm posting this as an answer because it's too long for a comment.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/19301&quot;&gt;Jeffrey's answer&lt;/a&gt; got me looking at the recommendations of the International Union of Pure and Applied Chemistry (IUPAC), &quot;the world authority on chemical nomenclature, terminology [...].&quot; They published &lt;em&gt;&lt;a href=&quot;https://iupac.org/wp-content/uploads/2019/05/IUPAC-GB3-2012-2ndPrinting-PDFsearchable.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Quantities, Units and Symbols in Physical Chemistry&lt;/a&gt;&lt;/em&gt;, AKA the &quot;Green Book&quot;. Section 3.10.1 (page 97) reads:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Fractions such as relative uncertainty, amount-of-substance fraction &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; (also called amount fraction), mass fraction &lt;span class=&quot;math-container&quot;&gt;$w$&lt;/span&gt;, and volume fraction &lt;span class=&quot;math-container&quot;&gt;$\varphi$&lt;/span&gt; (see Section 2.10, p. 47 for all these quantities), are sometimes expressed in terms of the symbols in the table below. [...] These multiples of the unit one are not part of the SI and ISO recommends that these symbols should never be used. [...] Even then, the use of an appropriate SI unit ratio may be preferred. Examples: The mass fraction &lt;span class=&quot;math-container&quot;&gt;$w$&lt;/span&gt; = 1.5 &lt;span class=&quot;math-container&quot;&gt;$\times$&lt;/span&gt; 10&lt;span class=&quot;math-container&quot;&gt;$^{−6}$&lt;/span&gt; = 1.5 mg/kg.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, I guess we should not write a rock has a SiO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; content of 64.2 wt%, but rather that the SiO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; content is 0.642, or better 642 g/kg, which looks weird. I've never seen this written anywhere. The funny thing is that on the next page (p. 98), there is another table which says that ppm, ppb... are deprecated and should be replaced by µmol/mol and equivalents. Again, I've never seen this written anywhere, all papers use ppm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I guess the conclusion of this is: there are conventions, and then there is common usage, and sometimes usage goes against convention. I'm OK to follow the common usage, but I feel bad for the commissions working hard on proper terminology, publishing entire books about it, if nobody follows them in the end...&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-02-25T16:26:11.540" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19314" PostTypeId="1" CreationDate="2020-02-25T03:39:05.703" Score="6" ViewCount="3612" Body="&lt;p&gt;I'm confused about how increased &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; concentration in the atmosphere affects the pH of the ocean. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The increase in &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; concentration means the pH of the ocean will decrease (by several chemical reactions). However, as there is more &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; in the atmosphere, ocean temperatures will rise meaning the ocean will absorb less &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt;, likely slowing down ocean acidification.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In short, the rise in &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; seems to have two contrasting effects on the pH of the ocean. Am I interpreting this correctly? If so, how is ocean acidification a problem? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For reference, the article I read is &lt;a href=&quot;https://www.nature.com/scitable/knowledge/library/ocean-acidification-25822734/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Barker and Ridgwell (2012)&lt;/a&gt;, Ocean Acidification, &lt;em&gt;Nature Education Knowledge&lt;/em&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="awehpionv" LastEditorUserId="106" LastEditDate="2020-05-07T11:26:49.167" LastActivityDate="2020-05-07T13:39:02.497" Title="The effect of CO2 concentration on the pH of the ocean" Tags="|oceanography|geochemistry|co2|carbon-cycle|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19315" PostTypeId="2" ParentId="19314" CreationDate="2020-02-25T18:29:36.510" Score="4" Body="&lt;p&gt;Increasing CO&lt;sub&gt;2&lt;/sub&gt; concentration in the atmosphere is leading to an increasing concentration of dissolved CO&lt;sub&gt;2&lt;/sub&gt; in sea-water. The dissolved CO&lt;sub&gt;2&lt;/sub&gt; then reacts with the water to create &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonic_acid&quot; rel=&quot;nofollow noreferrer&quot;&gt;carbonic acid&lt;/a&gt;, decreasing the pH as recognised in the question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The solubility of CO&lt;sub&gt;2&lt;/sub&gt; in water does decrease with increasing temperatures, so the maximum amount of CO&lt;sub&gt;2&lt;/sub&gt; that can be dissolved is being decreased as global temperatures rise, but the oceans are not yet saturated. There is a some further discussion and references om this page by NASA: &lt;a href=&quot;https://earthobservatory.nasa.gov/features/OceanCarbon&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Oceans Carbon Balance&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Should global temperatures reach a point at which the oceans are saturated and start to release CO&lt;sub&gt;2&lt;/sub&gt; that they have been absorbing since the start of the industrial revolution, there would be very serious consequences for us all. This is, naturally, the subject of much ongoing research, e.g. &lt;a href=&quot;https://sos.noaa.gov/datasets/ocean-atmosphere-co2-exchange/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ocean-Atmosphere CO&lt;sub&gt;2&lt;/sub&gt; Exchange&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="17518" LastEditorUserId="2470" LastEditDate="2020-05-07T13:39:02.497" LastActivityDate="2020-05-07T13:39:02.497" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19316" PostTypeId="1" CreationDate="2020-02-25T19:43:36.233" Score="4" ViewCount="195" Body="&lt;p&gt;I am trying to perform the calculation that Luis Alvarez used to establish the size of the K-T impactor. I used the following information:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Assume that the clay layer with iridium was uniformly distributed around Earth by the impact.&lt;/li&gt;&#xA;&lt;li&gt;On average, the layer had a concentration of iridium of 10 parts per billion (ppb) by weight.&lt;/li&gt;&#xA;&lt;li&gt;On average, the layer was 4 cm thick.&lt;/li&gt;&#xA;&lt;li&gt;The density of the layer was 2.5 g/cm&lt;sup&gt;3&lt;/sup&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Assume the meteor was spherical, with a density of 6.0 g/cm&lt;sup&gt;3&lt;/sup&gt;, and an iridium content of 0.5 parts per million (ppm) by weight.&lt;/li&gt;&#xA;&lt;li&gt;The radius of Earth is 6378 km.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;What is the diameter of the meteorite? The answer isn't exactly 10 km, as stated. By how much would you have to change the assumed thickness of the iridium layer to arrive at an asteroid diameter of exactly 10 km? &lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;My attempt:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$m_{layer} = \pi(2.5 g/cm^3)((6378 \cdot 10^5)^4 - (6378 \cdot 10^5 - 4)^4) = 3.26 \cdot 10^{28} g$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$m_{iridiuminlayer} = (3.26 \cdot 10^{28})(10^{-8}) = 3.26\cdot 10^{20} g$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is where I get stuck. It seems there is not sufficient information to calculate the radius of the meteor, as D = m/V, and we are given density and a mass ratio. I tried doing the second portion, in which you assume the diameter of the asteroid is 10 km, calculating the mass of the meteor, the iridium in the meteor, and the average iridium distribution over Earth's surface. I would be able to solve the rest of the question if I knew how to calculate the Volume/mass of the meteor. Please help!&lt;/p&gt;&#xA;" OwnerUserId="19014" LastEditorUserId="2470" LastEditDate="2020-02-26T00:15:48.620" LastActivityDate="2020-02-27T20:27:21.397" Title="Luis Alvarez's K-T Impactor Calculation" Tags="|geology|meteorite|earth-system|impacts|asteroids|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19317" PostTypeId="1" CreationDate="2020-02-25T19:44:58.317" Score="6" ViewCount="134" Body="&lt;p&gt;I am currently working on a project with my university and ran into trouble. I am building an application for indoor localization and am currently trying to benchmark our implementation. To do this I use some data sets with reference values which contain the latitude and longitude of a scanned point, but I can't figure out, how to interpret these kind of coordinates:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Latitude: 4864889.6629166845&lt;br&gt;&#xA;Longitude: -7515.916799399859&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://archive.ics.uci.edu/ml/datasets/ujiindoorloc#&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; is the link to the data sheet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Maybe one of you guys has some experience with this and can help me out, thanks for your help!&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Per request in comments, here's some of the data and explanation &lt;s&gt;in case&lt;/s&gt; when the link rots (they always do!):&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Attribute Information:&#xA;&#xA;Attribute 001 (WAP001): Intensity value for WAP001. Negative integer values from -104 to 0 and +100. Positive value 100 used if WAP001 was not detected.&#xA;....&#xA;Attribute 520 (WAP520): Intensity value for WAP520. Negative integer values from -104 to 0 and +100. Positive Vvalue 100 used if WAP520 was not detected.&#xA;Attribute 521 (Longitude): Longitude. Negative real values from -7695.9387549299299000 to -7299.786516730871000&#xA;Attribute 522 (Latitude): Latitude. Positive real values from 4864745.7450159714 to 4865017.3646842018.&#xA;Attribute 523 (Floor): Altitude in floors inside the building. Integer values from 0 to 4.&#xA;Attribute 524 (BuildingID): ID to identify the building. Measures were taken in three different buildings. Categorical integer values from 0 to 2.&#xA;Attribute 525 (SpaceID): Internal ID number to identify the Space (office, corridor, classroom) where the capture was taken. Categorical integer values.&#xA;Attribute 526 (RelativePosition): Relative position with respect to the Space (1 - Inside, 2 - Outside in Front of the door). Categorical integer values.&#xA;Attribute 527 (UserID): User identifier (see below). Categorical integer values.&#xA;Attribute 528 (PhoneID): Android device identifier (see below). Categorical integer values.&#xA;Attribute 529 (Timestamp): UNIX Time when the capture was taken. Integer value.&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Data Set Information:&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Many real world applications need to know the localization of a user in the world to provide their services. Therefore, automatic user localization has been a hot research topic in the last years. Automatic user localization consists of estimating the position of the user (latitude, longitude and altitude) by using an electronic device, usually a mobile phone. Outdoor localization problem can be solved very accurately thanks to the inclusion of GPS sensors into the mobile devices. However, indoor localization is still an open problem mainly due to the loss of GPS signal in indoor environments. Although, there are some indoor positioning technologies and methodologies, this database is focused on WLAN fingerprint-based ones (also know as WiFi Fingerprinting).&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Although there are many papers in the literature trying to solve the indoor localization problem using a WLAN fingerprint-based method, there still exists one important drawback in this field which is the lack of a common database for comparison purposes. So, UJIIndoorLoc database is presented to overcome this gap. We expect that the proposed database will become the reference database to compare different indoor localization methodologies based on WiFi fingerprinting.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The UJIIndoorLoc database covers three buildings of Universitat Jaume I with 4 or more floors and almost 110.000m2. It can be used for classification, e.g. actual building and floor identification, or regression, e.g. actual longitude and latitude estimation. It was created in 2013 by means of more than 20 different users and 25 Android devices. The database consists of 19937 training/reference records (trainingData.csv file) and 1111 validation/test records (validationData.csv file).&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The 529 attributes contain the WiFi fingerprint, the coordinates where it was taken, and other useful information.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Each WiFi fingerprint can be characterized by the detected Wireless Access Points (WAPs) and the corresponding Received Signal Strength Intensity (RSSI). The intensity values are represented as negative integer values ranging -104dBm (extremely poor signal) to 0dbM. The positive value 100 is used to denote when a WAP was not detected. During the database creation, 520 different WAPs were detected. Thus, the WiFi fingerprint is composed by 520 intensity values.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Then the coordinates (latitude, longitude, floor) and Building ID are provided as the attributes to be predicted.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Additional information has been provided.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The particular space (offices, labs, etc.) and the relative position (inside/outside the space) where the capture was taken have been recorded. Outside means that the capture was taken in front of the door of the space.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Information about who (user), how (android device &amp;amp; version) and when (timestamp) WiFi capture was taken is also recorded.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="19015" LastEditorUserId="6031" LastEditDate="2020-02-26T01:28:31.867" LastActivityDate="2021-09-10T03:10:36.820" Title="How to interpret these kind of coordinates?" Tags="|geography|data-formats|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19318" PostTypeId="2" ParentId="19317" CreationDate="2020-02-25T20:58:44.287" Score="8" Body="&lt;p&gt;After quite some research it turns out these are EPSG:3857 WGS 84 / Pseudo-Mercator coordinates.&lt;br&gt;&#xA;I found this out by visiting &lt;a href=&quot;https://epsg.io&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt; website where you can transform coordinates from different systems. &lt;/p&gt;&#xA;" OwnerUserId="19015" LastEditorUserId="19015" LastEditDate="2020-02-25T21:12:39.213" LastActivityDate="2020-02-25T21:12:39.213" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19319" PostTypeId="1" AcceptedAnswerId="19320" CreationDate="2020-02-26T00:23:34.323" Score="3" ViewCount="90" Body="&lt;p&gt;I am learning about geology and mining concepts.&#xA;Can someone please explain me what does &quot;Spatial Continuity&quot; is only applied on spatial variables like some data on spatial area OR it can as well be applied on say data from crushing mills, or rock processing units or any streaming data?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks &lt;/p&gt;&#xA;" OwnerUserId="19018" LastActivityDate="2020-02-26T01:11:13.493" Title="Spatial continuity" Tags="|mining|geospatial|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19320" PostTypeId="2" ParentId="19319" CreationDate="2020-02-26T01:11:13.493" Score="2" Body="&lt;p&gt;With reference to geology and mining, spatial continuity applies to the grades of the commodity of interest, insitu in the ground - grams per tonne of gold or percent of iron, copper or zinc. Grades (sample assays) within a sample hole are compared with each other and with grades from nearby holes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Spatial continuity is important when &lt;a href=&quot;https://en.wikipedia.org/wiki/Geostatistics&quot; rel=&quot;nofollow noreferrer&quot;&gt;geostatistics&lt;/a&gt; is used when estimating resources and reserves for a deposit.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The spatial continuity of the random variables is described by a model of spatial continuity that can be either a parametric function in the case of variogram-based geostatistics, or have a non-parametric form when using other methods such as multiple-point simulation or pseudo-genetic techniques.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In mining, spatial continuity only applies to geology models. It does not apply to processing plant or anything associated with the processing plant.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The processing plant receives broken ore, which by the time it has reached by the processing plant is so mixed up there is no mathematical correlation between batches of ore. This is particularly true when ore is sourced from multiple areas within a deposit, or from multiple deposits, for either blending purposes or because the processing plant must receive a certain quantity of ore on a daily basis.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-02-26T01:11:13.493" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19321" PostTypeId="1" CreationDate="2020-02-26T01:46:19.880" Score="4" ViewCount="368" Body="&lt;p&gt;I have data like this of rocks from 3 blast holes:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yRJDw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yRJDw.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are the rock properties of each blast hole of a mining site. The rock properties come from the Block model of that mining site.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I want to calculate the spatial continuity of these blast holes with up to V(X+12) for having 12 r square values. I am trying to program this in python.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone help me with the logic of how do we go about calculating that for such data?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="19018" LastActivityDate="2020-02-26T02:24:47.390" Title="Spatial Continuity in python" Tags="|rocks|statistics|mining|geospatial|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19322" PostTypeId="1" CreationDate="2020-02-26T02:17:20.997" Score="5" ViewCount="137" Body="&lt;p&gt;I have a bunch of semi-precious stones here, but I am not very learned in geology etc and I would like to have some way to know what kind of stones they are. As far as I understand question about stone identification are considered off-topic here. Is there such a reliable source so I can identify the stones by myself? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;" OwnerUserId="19019" LastEditorUserId="6031" LastEditDate="2020-02-26T07:15:29.973" LastActivityDate="2020-03-22T01:07:19.923" Title="Sources or strategies for stone identification" Tags="|geology|rocks|terminology|crystals|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19323" PostTypeId="2" ParentId="19321" CreationDate="2020-02-26T02:24:47.390" Score="5" Body="&lt;p&gt;Your last question was easy to answer, this one is more difficult. You could look at &lt;a href=&quot;https://en.wikipedia.org/wiki/Correlation_and_dependence&quot; rel=&quot;noreferrer&quot;&gt;correlation and dependence&lt;/a&gt;, but you'd be better off looking at &lt;a href=&quot;https://en.wikipedia.org/wiki/Variogram&quot; rel=&quot;noreferrer&quot;&gt;variography&lt;/a&gt;. That's the easier part of this question dealt with.  Most resource geologists do not deal with correlation &amp;amp; dependence, they do variography studies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are dealing with a small data set to familiarize yourself with the concept of spatial continuity then writing code in any suitable computer language is okay. If however, you are analyzing a large or complex data set use a package which has been created to analyze such data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To analyze a large or complex data set, the data will first have to be declustered so that data points are fairly uniformly distributed throughout the data set. The other thing that will then need to be done is to establish a three dimension search ellipsoid so that only data within the 3D ellipsoid is considered with each calculation of the variance - the 3D ellipsoid will be similar in shape to a rugby football or an Australian Rules football. The 3D ellipsoid will also have to be able to orientated in a specified search direction. It will then have to be positioned on each declustered data point and geostatistical variances determined for each point - note, the mathematical expression for geostatistical variance is slightly different to the one used by mathematicians - you can blame &lt;a href=&quot;https://en.wikipedia.org/wiki/Georges_Matheron&quot; rel=&quot;noreferrer&quot;&gt;George Matheron&lt;/a&gt; for that. &lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-02-26T02:24:47.390" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19324" PostTypeId="1" CreationDate="2020-02-26T04:52:52.643" Score="5" ViewCount="80" Body="&lt;p&gt;24-Feb-2020 NASA News item &lt;a href=&quot;https://mars.nasa.gov/news/8613/a-year-of-surprising-science-from-nasas-insight-mars-mission/&quot; rel=&quot;nofollow noreferrer&quot;&gt;A Year of Surprising Science From NASA's InSight Mars Mission&lt;/a&gt; says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A new understanding of Mars is beginning to emerge, thanks to the first year of NASA's InSight lander mission. Findings described in a set of six papers published today reveal a planet alive with quakes, dust devils &lt;strong&gt;and strange magnetic pulses.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and later:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In addition, scientists are intrigued by how these signals change over time. The measurements vary by day and night; &lt;strong&gt;they also tend to pulse around midnight. Theories are still being formed as to what causes such changes, but one possibility is that they're related to the solar wind interacting with the Martian atmosphere.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Okay that's one possibility, but what are &lt;em&gt;any&lt;/em&gt; of the others that have been considered? Or is this actually the only known possible explanation?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Possibly helpful:&lt;/strong&gt; &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021JA030238&quot; rel=&quot;nofollow noreferrer&quot;&gt;Discrete Aurora at Mars: Dependence on Upstream Solar Wind Conditions&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2022-05-21T22:26:16.350" LastActivityDate="2022-05-21T22:26:16.350" Title="Mars' strange magnetic pulses at midnight; besides the solar wind what are other possible causes?" Tags="|planetary-science|geomagnetism|solar-terrestrial-physics|mars|magnetosphere|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19325" PostTypeId="1" CreationDate="2020-02-26T04:57:55.130" Score="5" ViewCount="99" Body="&lt;p&gt;24-Feb-2020 NASA News item &lt;a href=&quot;https://mars.nasa.gov/news/8613/a-year-of-surprising-science-from-nasas-insight-mars-mission/&quot; rel=&quot;nofollow noreferrer&quot;&gt;A Year of Surprising Science From NASA's InSight Mars Mission&lt;/a&gt; says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A new understanding of Mars is beginning to emerge, thanks to the first year of NASA's InSight lander mission. Findings described in a set of six papers published today reveal a planet alive with quakes, dust devils &lt;strong&gt;and strange magnetic pulses.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and later:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In addition, scientists are intrigued by how these signals change over time. The measurements vary by day and night; &lt;strong&gt;they also tend to pulse around midnight. Theories are still being formed as to what causes such changes, but one possibility is that they're related to the solar wind interacting with the Martian atmosphere.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Okay, how could the solar wind cause magnetic pulses &lt;strong&gt;at midnight&lt;/strong&gt;, when the Sun is on the opposite side of the planet?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Possibly helpful:&lt;/strong&gt; &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021JA030238&quot; rel=&quot;nofollow noreferrer&quot;&gt;Discrete Aurora at Mars: Dependence on Upstream Solar Wind Conditions&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2022-05-21T22:25:58.433" LastActivityDate="2022-05-21T22:25:58.433" Title="How could the solar wind cause strange magnetic pulses on Mars at midnight?" Tags="|planetary-science|geomagnetism|sun|solar-terrestrial-physics|mars|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19326" PostTypeId="1" AcceptedAnswerId="19346" CreationDate="2020-02-26T09:09:40.200" Score="5" ViewCount="308" Body="&lt;p&gt;I frequently read &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; have a spatially constant concentration sadly rising and at 415ppm at present. That concentration do not vary a lot spatially I think. You will find ~415ppm at Argentina or at Taiwan.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However this is not the case for &lt;span class=&quot;math-container&quot;&gt;$\ce{H2O}$&lt;/span&gt;; some regions are dry, some others are wet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can you explain to someone not trained in atmospheric sciences what makes &lt;span class=&quot;math-container&quot;&gt;$\ce{H2O}$&lt;/span&gt; especial?&lt;/p&gt;&#xA;" OwnerDisplayName="user18590" LastActivityDate="2020-02-28T20:02:33.230" Title="Why isn't $\ce{H2O}$ evenly distributed in Earth's atmosphere?" Tags="|atmosphere|atmospheric-chemistry|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19327" PostTypeId="2" ParentId="19322" CreationDate="2020-02-26T10:07:10.993" Score="2" Body="&lt;p&gt;Are your stones raw or are they cut &amp;amp; polished as they would appear if mounted in jewellery pieces? There are tests such as streak &amp;amp; hardness which can be done to raw stones but not to polished stones because these test would damage the polished surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are a number of websites that can be used, such as:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.thoughtco.com/rock-identification-tables-1441174&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rock Identification Made Easy&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://geology.com/rocks/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rocks: Igneous, Metamorphic and Sedimentary&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Tests that should be done include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Color&lt;/li&gt;&#xA;&lt;li&gt;Luster&lt;/li&gt;&#xA;&lt;li&gt;Hardness - usually involves testing with the blade of a pocket knife&#xA;or similar&lt;/li&gt;&#xA;&lt;li&gt;Grain size - the size of mineral grains in the stones. If no mineral&#xA;grains are obvious the stone may be &quot;glassy&quot;&lt;/li&gt;&#xA;&lt;li&gt;Streak - the color left on a piece of white ceramic when the stone is&#xA;rubbed on the ceramic.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-02-26T10:07:10.993" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19328" PostTypeId="2" ParentId="19304" CreationDate="2020-02-26T10:39:29.840" Score="3" Body="&lt;p&gt;Water (solid or liquid) has some absorbtion. It is rather low for pure water for visible or near-visible light and that's why water it is considered transparent. But only to an extent - few meters of water look blue and few hundred meters look black, esp. if you are UNDER those few hundred meters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then we have snow. Snow has an abundance of optical boundaries in all directions, so it scatters the light well. The light passes only few milimeters water in total before it gets reflected or refracted out of the snow mass. You don't absorb much light in a few mm of water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you compress or melt the snow, optical boundaries disappear and the light is allowed to go deep in the water body where it gets chance to be absorbed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;p.s. Water is not the only substance that looks white when powdered. Most powdered substances tend to look white-ish, even if in their solid form they are pretty much not white and just partially transparent. See sulfur, copper sulfate and so on.&lt;/p&gt;&#xA;" OwnerUserId="18660" LastActivityDate="2020-02-26T10:39:29.840" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19329" PostTypeId="2" ParentId="19326" CreationDate="2020-02-26T12:46:49.013" Score="0" Body="&lt;p&gt;The influence of the sun is greatest at the equator. The sun causes air to rise in three main cells or bands around the Earth north of the equator,with a similar arrangement south of the equator. The Hadley cells which rise up closest to the equator, both north and south, are by far the most important.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the air rises it cools and the pressure becomes lower, so it sheds its moisture as rain over an equatorial region which used to be covered in rain forest and where, despite the depredations of man, there is still a lot of rainforest left. These Hadley cells are the main reason why moisture and rainfall are unevenly distributed. Mountains and plateaus are another cause.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Having shed most of its moisture and moved north, in the northern hemisphere the Hadley cell descends over the Sahel and other desert and semi-desert areas around the globe. They are deserts, of course, because the dry air of the descending cell creates high pressure, so very little rainfall.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A similar state of affairs exists in the southern hemisphere, but as there is less land and more ocean to the south, there are fewer deserts than in the north.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-02-26T12:46:49.013" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19330" PostTypeId="2" ParentId="19326" CreationDate="2020-02-26T14:18:59.300" Score="8" Body="&lt;p&gt;The brief answer is 'the water cycle' I think.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A longer answer is that water can exist in many states on and above the surface: at least snow, ice and liquid water on and below the surface and water vapour (gas) and aerosols of liquid water or ice (clouds) in the atmosphere. On the other hand &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; can only exist in one: gas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What that means is that &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; is as well-mixed as any other long-lived gaseous component of the atmosphere over time, which is 'pretty well'.  Components of the atmosphere, such as &lt;span class=&quot;math-container&quot;&gt;$\mathrm{SO_2}$&lt;/span&gt;, which are not long-lived don't get mixed so well because they don't have time to be. For water the situation is even more complicated because there are complicated phase transitions going on within the atmosphere, and because the distribution of liquid water is extremely dependent on topography, and in particular it can move large distances from where it originates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The phase transitions of water in the atmosphere are driven by temperature and pressure conditions in the atmosphere, and in turn alter those conditions, and the whole system is chaotic of course.  The result of some of these phase transitions is water leaving the atmosphere as precipitation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How much water gets &lt;em&gt;into&lt;/em&gt; the atmosphere depends on conditions on the surface and in the atmosphere, and also on where water &lt;em&gt;is&lt;/em&gt; on the surface, which is extremely non-uniform (see above).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All of these transitions are driven by energy from the Sun which varies over the planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the end result of all that is that&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;water vapour is not long-lived in the atmosphere as a result of all this, so it doesn't have time to become well-mixed;&lt;/li&gt;&#xA;&lt;li&gt;water is not evenly-distributed on and below the surface because it's mostly liquid (and because snow &amp;amp; ice is only stable in some parts of the surface);&lt;/li&gt;&#xA;&lt;li&gt;the behaviour of water entering, moving within, and leaving the atmosphere is extremely complex and chaotic (or 'there is weather'), resulting in large variations over a range of scales in distribution of the various states of water which can live in the atmosphere, and large variations in how much water leaves the atmosphere over various scales.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerDisplayName="user18801" LastEditorDisplayName="user18801" LastEditDate="2020-02-26T14:39:26.857" LastActivityDate="2020-02-26T14:39:26.857" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19331" PostTypeId="1" CreationDate="2020-02-26T14:58:20.867" Score="1" ViewCount="64" Body="&lt;p&gt;Favourable condition for the formation of porphyry copper deposits is :&#xA;1. Extremely low oxygen fugacity in initial magma&#xA;2. High water content in initial magma&#xA;3. Crystallization of magama at deep crustal level&#xA;4. Crystallization of magama at earth's surface&lt;/p&gt;&#xA;" OwnerUserId="18747" LastActivityDate="2020-02-26T14:58:20.867" Title="What are the favourable conditions for the formation of porphyry copper deposits?" Tags="|geology|geochemistry|economic-geology|ore|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19332" PostTypeId="1" CreationDate="2020-02-26T19:57:44.860" Score="5" ViewCount="143" Body="&lt;p&gt;I'm no expert and barely have any idea about this. But I want to know if the methods in calculating the Local Magnitude can only be done manually? I mean manually by first reading a seismograph, identifying the distance of the epicenter using the distance between P-S waves, and then measuring the height of the highest amplitude. Or are there software, APIs, and etc that can do this automatically by just providing the seismograph data. Or there's no way to calculate the Local Magnitude without a human input?&lt;/p&gt;&#xA;" OwnerUserId="19024" LastEditorDisplayName="user967" LastEditDate="2020-02-26T20:00:04.080" LastActivityDate="2020-11-24T02:02:00.160" Title="What are today's methods in calculating the Local Magnitude of earthquakes?" Tags="|seismology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19333" PostTypeId="2" ParentId="19316" CreationDate="2020-02-26T20:47:19.853" Score="4" Body="&lt;p&gt;The volume of a sphere is &lt;span class=&quot;math-container&quot;&gt;$\small\sf{\frac4 3\pi R^3}$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$\small\sf{R}$&lt;/span&gt; is the radius.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The volume of Earth with the 4 cm deep iridium rich layer is,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\small\sf{V_{Ei} = \frac 4 3\pi (6.378\cdot10^6)^3}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\small\sf{m^3}$&lt;/span&gt; = &lt;span class=&quot;math-container&quot;&gt;$\small\sf{1.086 \ 781 \cdot 10^{21}}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\small\sf{m^3}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The volume of the 4 cm deep iridium rich layer is,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\small\sf{V_i = \frac 4 3\pi (6.378\cdot10^6)^3} -\frac 4 3\pi (6.378\cdot10^6 - 0.04)^3 $&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\small\sf{m^3}$&lt;/span&gt; = &lt;span class=&quot;math-container&quot;&gt;$\small\sf{2.044 \cdot 10^{13}}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\small\sf{m^3}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, density is mass divided by volume, &lt;span class=&quot;math-container&quot;&gt;$\small\sf{\rho = m/v}$&lt;/span&gt;, thus the mass of the iridium rich layer is,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\small\sf{m_i = 2.5 \cdot 2.044 \cdot 10^{13} = 5.110 \cdot 10^{13}}$&lt;/span&gt; tonnes&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The proportion of iridium in the layer is 10 ppb, therefore the mass of iridium within the layer is,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\small\sf{5.110 \cdot 10^{13} \cdot 10 \cdot 10^{-9}} = 511 \ 000$&lt;/span&gt; tonnes&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, the proportion of iridium in the meteor was 0.5 ppm, therefore the mass of the meteor was,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\small\sf{511 \ 000 / (0.5 \cdot 10^{-6}) = 1.0220 \cdot 10^{12}}$&lt;/span&gt; tonnes&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The density of the meteor was  &lt;span class=&quot;math-container&quot;&gt;$\small\sf{6.0 \ g/cm^3}$&lt;/span&gt;, which is the same as &lt;span class=&quot;math-container&quot;&gt;$\small\sf{6.0 \ t/m^3}$&lt;/span&gt;, therefore, the volume of the meteor was,&#xA;&lt;span class=&quot;math-container&quot;&gt;$\small\sf{1.0220 \cdot 10^{12}/6.0} = 1.703 \ 333 \cdot 10^{11} m^3$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using this and the equation for the volume of a sphere, the radius of the meteor was,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\small\sf{\sqrt[3](\frac 3{4\pi} \cdot 1.703 \ 333 \cdot 10^{11})} = 3438.774 \ m$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and the diameter of the meteor was 6877.5 m or 6.878 km&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not the 10 km you wanted.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;To get the thickness you want for a 10 km diameter meteor, do the calculation in reverse.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For diameter of 10 000 m, the volume of a spherical meteor would have been,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\small\sf{\frac 4 3 \cdot \pi \cdot 5000^3} = 523.598 \ 776 \cdot 10^9 \ m^3$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With a density of &lt;span class=&quot;math-container&quot;&gt;$\small\sf{6 \ t/m^3}$&lt;/span&gt;, the mass of meteor would have been,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\small\sf{6(523.598 \ 776 \cdot 10^9)} = 3.141 \ 592 \ 6 \cdot 10^{12} t$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;with a metal grade of 0.5 ppm of iridium, the mass of iridium in the meteor would have been,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\small\sf{3.141 \ 592 \ 6 \cdot 10^{12} \cdot 0.5 \cdot 10^{-6} = 1 \ 570 \ 796 \ t}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The metal grade of iridium in the layer on the Earth is 10 ppb, therefore the mass of the iridium layer is,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\small\sf{(1 \ 570 \ 796)/ (10 \cdot 10^{-9}) = 1.570 \ 796\ 327 \cdot 10 ^{14} \ t}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With a density of &lt;span class=&quot;math-container&quot;&gt;$\small\sf{2.5\  t/m^3}$&lt;/span&gt;, the volume of the layer is,&#xA;&lt;span class=&quot;math-container&quot;&gt;$\small\sf{(1.570 \ 796\ 327 \cdot 10 ^{14})/2.5 = 6.283 \ 185 \cdot 10^{13} \ m^3}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the previous calculation, the volume of layer is,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\small\sf{6.283 \ 185 \cdot 10^{13} = \frac 4 3\pi (6.378\cdot10^6)^3} -\frac 4 3\pi (6.378\cdot10^6 - x)^3 $&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\small\sf{m^3}$&lt;/span&gt; = &lt;span class=&quot;math-container&quot;&gt;$\small\sf{2.044 \cdot 10^{13}}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\small\sf{m^3}$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Solving for &lt;span class=&quot;math-container&quot;&gt;$\small\sf{x}$&lt;/span&gt;, which is the thickness of the layer, gives &lt;span class=&quot;math-container&quot;&gt;$\small\sf{x} = 0.123\ m\ or\ 12.3\ cm$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2020-02-27T20:27:21.397" LastActivityDate="2020-02-27T20:27:21.397" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19334" PostTypeId="1" CreationDate="2020-02-26T21:20:17.830" Score="4" ViewCount="906" Body="&lt;p&gt;It is readily apparent from the fossil record that the first limestone was laid down hundreds of millions of years ago, but how long ago was the very first limestone formed? It could be approximately dated by its fossils, but what if it was in the Precambrian and contained no fossils - how could it be accurately dated then?&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2022-03-10T23:17:54.307" Title="How long ago was the first limestone formed?" Tags="|earth-history|fossils|limestone|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19336" PostTypeId="1" CreationDate="2020-02-27T01:25:55.437" Score="4" ViewCount="49" Body="&lt;p&gt;On Earth or an Earth-like planet, how long does it take for a molten surface to solidify into planetary crust, and how long does it take for that crust to develop into tectonic plates?&lt;/p&gt;&#xA;" OwnerUserId="19026" LastActivityDate="2020-02-27T01:25:55.437" Title="How long for tectonic plates to develop from a planetary, molten planetary surface?" Tags="|geophysics|plate-tectonics|planetary-science|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19337" PostTypeId="1" CreationDate="2020-02-27T14:06:09.330" Score="5" ViewCount="651" Body="&lt;p&gt;I usually read &lt;a href=&quot;https://eprints.ucm.es/57547/&quot; rel=&quot;noreferrer&quot;&gt;that Iberia is a subplate&lt;/a&gt;, while India is a plate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But it was a plate at the beginning of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Alpine_orogeny&quot; rel=&quot;noreferrer&quot;&gt;Alpine Orogeny&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Tectonic_map_Mediterranean_EN.svg&quot; rel=&quot;noreferrer&quot;&gt;wikimedia.org&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Ua42k.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ua42k.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;sub&gt;&lt;em&gt;Description: Tectonic map of southern Europe, North Africa and&#xA;  the Middle East, showing tectonic structures of the western Alpide&#xA;  mountain belt. Only Alpine (tertiary) structures are shown.&lt;/em&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Both were plates that collided with the Eurasian Plate, forming respectively Himalaya and Pyrenees chains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What makes Iberia a subplate and not a plate like that of India?&lt;/p&gt;&#xA;" OwnerDisplayName="user18590" LastEditorDisplayName="user18590" LastEditDate="2020-02-27T14:33:52.637" LastActivityDate="2021-01-17T13:00:25.183" Title="Why isn't Iberia a tectonic plate?" Tags="|geology|plate-tectonics|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19339" PostTypeId="2" ParentId="19337" CreationDate="2020-02-27T15:04:26.407" Score="1" Body="&lt;p&gt;The Iberian plate may have been a sub-plate once-upon-a-time, but in modern maps it is usually shown as part of the Eurasian plate, and the next plate to it is the African plate. The same thing applies to the so-called Indian plate. Prior to 43 million years ago it was indeed a separate plate, but then it fused with the Australian plate and there is no longer a plate boundary between India and Australia. The resulting plate is therefore usually referred to as the Indo-Australian plate. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A lot can happen in tens of millions of years, and one of the things that can happen is a change in plate boundaries. There is no longer a plate boundary between what was the Iberian plate and the Eurasian plate. If you are referring to events which happened tens of millions of years ago, it might make sense to refer to them a separate plates, which is why the article you quote refers to an Iberian sub-plate.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-02-27T15:04:26.407" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19340" PostTypeId="1" CreationDate="2020-02-27T18:24:21.123" Score="3" ViewCount="101" Body="&lt;p&gt;Sicily is a geologically complex island which seems to have been extensively studied geologically and from a tectonically point of view. There are an overwhelming number of papers dealing with the strata and when they were formed but remarkably little information of the dichotomy between emergent and submerged Sicily and the extent of the former since the Messinian Salinity crisis (5.33 Ma).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Actually, when dealing with this cornerstone moment in the history of the Mediterranean, most papers represent a modern-looking Sicily and Italy even if there is multiple evidence they didn't at all look like they do now, mostly because of the intensive tectonics that opened the Tyrrhenian basin, formed the Sicilian strait and accreted the Peloritan block onto Adria and the African plate, forming Sicily as we know now.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is known that this Peloritan block (including the Kabylies, Calabria and the eastern tip of Sicily) moved NW-SE during the last 20 Ma converging with Africa and Adria, and its parts rotating in a clockwise motion into nowadays Sicily but not a single work depicts these as islands or makes the move to recreate emerged land through time. This would be ideal for reconstructions of the movement of biota through the Mediterranean through time. &lt;/p&gt;&#xA;" OwnerUserId="19032" LastEditorUserId="19032" LastEditDate="2020-02-28T18:49:14.173" LastActivityDate="2020-02-28T18:49:14.173" Title="Where and how big was Sicily between 5 and 1 Ma ago?" Tags="|geology|plate-tectonics|tectonics|mediterranean|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19341" PostTypeId="2" ParentId="19332" CreationDate="2020-02-28T00:32:48.517" Score="1" Body="&lt;p&gt;According to the equation for local magnitude calculation I give my answer: Of course there is a lot of algorithms for auto-picking, in fact, the magnitude value that you see in the first report (immediately) after an earthquake is (almost always) an automatic calculation. &lt;a href=&quot;https://academic.oup.com/gji/article/199/1/368/731808&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://academic.oup.com/gji/article/199/1/368/731808&lt;/a&gt;. However, the P and S picked time is checked but humans in order to improve the accuracy. I think the human verification is always necessary and obligatory, because some earthquake are complex signals. &lt;img src=&quot;https://i.stack.imgur.com/YQBD7.jpg&quot; alt=&quot;seismogram showing some complex earthquake signal logs in Colombia&quot;&gt;!. Moreover, the point here is not the human-based method, I thing it should be focused on the quality control system. &lt;/p&gt;&#xA;" OwnerUserId="8507" LastActivityDate="2020-02-28T00:32:48.517" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19345" PostTypeId="2" ParentId="19303" CreationDate="2020-02-28T16:54:34.630" Score="10" Body="&lt;p&gt;You can definitely see a large geomagnetic storm with a compass, if you have the timing to catch one and the patience to sit and stare for a few minutes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you look at &lt;a href=&quot;https://www.intermagnet.org/data-donnee/dataplot-1-eng.php?year=2003&amp;amp;month=10&amp;amp;day=29&amp;amp;start_hour=0&amp;amp;end_hour=24&amp;amp;filter_region%5B%5D=America&amp;amp;filter_region%5B%5D=Asia&amp;amp;filter_region%5B%5D=Europe&amp;amp;filter_region%5B%5D=Pacific&amp;amp;filter_region%5B%5D=Africa&amp;amp;filter_lat%5B%5D=NH&amp;amp;filter_lat%5B%5D=NM&amp;amp;filter_lat%5B%5D=E&amp;amp;filter_lat%5B%5D=SM&amp;amp;filter_lat%5B%5D=SH&amp;amp;sort=iaga&amp;amp;iaga_code=LER&amp;amp;type=dif&amp;amp;fixed_scale=0&amp;amp;format=png&quot; rel=&quot;nofollow noreferrer&quot;&gt;these minutely measurements from Lerwick observatory&lt;/a&gt; for one of the more recent large storms (the 2003 Halloween storm), you can see a roughly 4.5 degree swing in declination (labelled &quot;D&quot;, the horizontal magnetic field angle to geographic North) over about 15 minutes at about 07:00. &quot;I&quot; is inclination, vertical field angle to the horizontal plane, &quot;F&quot; is total intensity of the field.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XIWAM.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XIWAM.png&quot; alt=&quot;Lerwick (LER) based on 1-minute definitive data 2003-10-29&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Lerwick (LER) based on 1-minute definitive data &lt;code&gt;2003-10-29&lt;/code&gt; shows plots for D and I in degrees and F in nT. D shows a dip to -2 degrees in the hour before &lt;code&gt;07:00&lt;/code&gt; UT and then a sudden rise to about +1.5  degrees at about &lt;code&gt;07:00&lt;/code&gt; with spikes to +2 degrees.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;It will depend on where you are as to how big this change in the magnetic field is, and how big the storm is. For this storm, the UK geomagnetic observatory network gives a good idea of how the effect seen depends on where you are.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Gh0kx.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Gh0kx.jpg&quot; alt=&quot;BGS 1-minute definitive observatory data across UK for 2003 Halloween Storm&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Compass angles (positive West, negative East) measured at BGS Lerwick, Eskdalemuir and Hartland observatories during &lt;code&gt;2003-10-29&lt;/code&gt; and &lt;code&gt;2003-10-30&lt;/code&gt;. The the biggest change is seen at Lerwick, a smaller change is seen at Eskdalemuir further to the south (further away from the auroral zone where the field changes are occurring), and a smaller change still at Hartland.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="14123" LastEditorUserId="14123" LastEditDate="2020-03-02T11:19:25.397" LastActivityDate="2020-03-02T11:19:25.397" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19346" PostTypeId="2" ParentId="19326" CreationDate="2020-02-28T20:02:33.230" Score="4" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;I frequently read CO&lt;sub&gt;2&lt;/sub&gt; has a spatially constant concentration sadly rising and at 415ppm at present. That concentration do not vary a lot spatially I think. You will find ~415ppm at Argentina or at Taiwan.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Your reading sources are overly simplistic. Carbon dioxide concentrations are not spatially constant, and the increase is not monotonic.  They instead vary by several percent over the course of a year and over the globe. This is particularly the case in the Northern Hemisphere, where CO&lt;sub&gt;2&lt;/sub&gt; concentrations increase during the winter when land plants are dormant but decrease during the summer when land plants draw down CO&lt;sub&gt;2&lt;/sub&gt; levels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The next two images portray these seasonal effects. The first image portrays CO&lt;sub&gt;2&lt;/sub&gt; concentrations over the world on 22 March 2105 while the second portrays concentrations five months later. Note that CO&lt;sub&gt;2&lt;/sub&gt; concentrations in the Northern Hemisphere dropped during this five month interval. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nRQxo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nRQxo.png&quot; alt=&quot;Free troposphere CO2 molar concentration, in parts per million (micromoles per mole), on 22 March 2015. Concentrations exceed 400 ppm through the northern hemisphere, and are nearly 410 ppm in isolated parts of the far north. Concentrations in the Southern Hemisphere are more uniform, and are almost uniformly below 400 ppm.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2rxKS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2rxKS.png&quot; alt=&quot;Free troposphere CO2 molar concentration, in parts per million (micromoles per mole), on 22 August 2015. Concentrations have dropped below 400 ppm over much of the northern hemisphere, and are at 390 ppm or less over broad swaths of the far north. Concentrations in the Southern Hemisphere are more uniform, but are a bit higher than they were five months earlier.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&#xA;The net change over the course of decades is, sadly, upward, as portrayed in the graph that follows. This graph portrays CO&lt;sub&gt;2&lt;/sub&gt; concentrations as directly measured at the observatory at the top of Mauna Loa. These measurements represent the longest continuous record of direct atmospheric CO&lt;sub&gt;2&lt;/sub&gt; concentration readings. The red curve shows the monthly averages. This curve exhibits a sinusoid-like curve atop a ramp. The black curve has the seasonal variations removed, making it much closer to a monotonic ramp.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JLf1B.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JLf1B.png&quot; alt=&quot;Atmospheric CO2 as measured at the Mauna Loa Observatory, from 1958 to 2019. This constitutes the longest record of direct measurements of CO2 in the atmosphere. Two curves are shown, a red curve that represents monthly averages, and a black curve that has seasonal variations removed.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Can you explain to someone not trained in atmospheric sciences what makes H&lt;sub&gt;2&lt;/sub&gt;O special?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Water is &lt;strong&gt;the&lt;/strong&gt; only common substance on Earth that exists as a solid, a liquid, and as a gas in the Earth's atmosphere. While some alcohols, some oils, and elemental bromine have somewhat similar melting points and boiling points, none of these is as stable chemically as is water, and none is anywhere as close to common as is water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Carbon dioxide remains in its gaseous state throughout all temperature and pressure ranges experienced in the Earth's atmosphere. (Aside: if CO&lt;sub&gt;2&lt;/sub&gt; levels were 2000 times what they are now, CO&lt;sub&gt;2&lt;/sub&gt; might well precipitate as CO&lt;sub&gt;2&lt;/sub&gt; snow at the Vostok Station. But that ridiculously high concentration level is not the case; CO&lt;sub&gt;2&lt;/sub&gt; will remain in its gaseous state throughout all temperature and pressure ranges experienced in the Earth's atmosphere.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Assuming that CO&lt;sub&gt;2&lt;/sub&gt; levels remain less than 2000 times higher than present means that CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere will always be in the gaseous state, which in turn means the CO&lt;sub&gt;2&lt;/sub&gt;-bearing capacity of the atmosphere is effectively infinite. On the other hand, the water-bearing capacity of the atmosphere depends very strongly on temperature. Air at 35°C at sea level can hold about 37 grams of water per kilogram of dry air before the water vapor starts to precipitate as rain. That's over 60 times the current CO&lt;sub&gt;2&lt;/sub&gt; molar concentration level. Air at -35°C can hold less than 0.2 grams of water per kilogram of dry air before the water vapor starts to precipitate as snow, which is less than the current CO&lt;sub&gt;2&lt;/sub&gt; molar concentration level.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The following graphic portrays the huge variations (&quot;huge&quot; compared to the several percent variations in CO&lt;sub&gt;2&lt;/sub&gt; concentration levels) in water concentration levels. The graph in question shows the monthly average total precipitable water vapor levels for May 2009.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yB5A2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yB5A2.jpg&quot; alt=&quot;Map showing total precipitable water vapor in the atmosphere in May 2009. Water vapor is highest near the equator, low in polar regions, and not even shown in the Antarctic.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-02-28T20:02:33.230" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19347" PostTypeId="1" CreationDate="2020-02-29T11:24:10.173" Score="7" ViewCount="1737" Body="&lt;p&gt;Hot springs in non-volcanic areas are attributed to the interaction of water with hot rocks deep in the earth's crust:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In non-volcanic areas, the temperature of rocks within the Earth also increases with depth—this temperature increase is known as the Geothermal Gradient. &lt;strong&gt;If water percolates deeply enough into the crust, it comes into contact with hot rocks and can circulate to the surface to form hot springs&lt;/strong&gt;.&lt;br&gt;&#xA;  &lt;sub&gt;&lt;a href=&quot;https://www.nps.gov/subjects/geology/hot-springs.htm&quot; rel=&quot;noreferrer&quot;&gt;Hot Springs/Geothermal Features&lt;/a&gt;, National Park Service&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;If I understand correctly, this heat comes from the decay of radioactive isotopes:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;... the vast majority of the heat in Earth's interior—up to 90 percent—is fueled by the decaying of radioactive isotopes like Potassium 40, Uranium 238, 235, and Thorium 232 contained within the mantle.&lt;br&gt;&#xA;  &lt;sub&gt;&lt;a href=&quot;https://phys.org/news/2006-03-probing-earth-core.html&quot; rel=&quot;noreferrer&quot;&gt;Probing Question: What heats the earth's core?&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Hence...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question&lt;/strong&gt;: Are hot springs in non-volcanic areas radioactive?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm guessing the answer is either &quot;no&quot; or &quot;yes, but not very&quot;, because people swim in them.  But it seems like radioactive isotopes should be seeping into the water.&lt;/p&gt;&#xA;" OwnerUserId="18754" LastActivityDate="2020-02-29T18:04:06.037" Title="Are hot springs in non-volcanic areas radioactive?" Tags="|geothermal-heat|geodynamics|radioactivity|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19348" PostTypeId="2" ParentId="19347" CreationDate="2020-02-29T18:04:06.037" Score="-3" Body="&lt;p&gt;The answer is contained within your own question. Virtually everything is radioactive, including your own body, the air you breathe, and everything you eat. The radioactivity is usually beta radiation (emission of energetic electrons), which is the least harmful form of radioactivity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Radon gas, which is emitted from granite rocks containing uranium, sometimes builds up to dangerous levels in our homes and is an alpha emitter. Alpha radiation is very ionising and dangerous, but needs to be ingested into the body to cause serious harm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer to your question, therefore, is yes, hot springs are radioactive, but so are cold springs. As hot springs are more likely to have passed through granite rocks, they are probably on average more radioactive than cold springs, but neither are radioactive enough to cause concern. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The radioactivity which is dangerous enough to cause concern is radon gas, which varies from place to place according to the underlying rocks. Maps of radon hotspots can be obtained from the internet. If you happen to live in a hotspot, you need to keep your house well ventilated, otherwise the radon will build up to dangerous levels, sometimes levels which would not be tolerated in a nuclear power station or research establishment.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-02-29T18:04:06.037" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19349" PostTypeId="1" CreationDate="2020-02-29T19:13:37.870" Score="5" ViewCount="77" Body="&lt;p&gt;This question s titled according to of one of the Nikola Tesla's patents. There he stated that lightning generates electric waves in Earth.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;In the course of certain investigations which I carried on for the&#xA;  purpose of studying the effects of lightning discharges upon the&#xA;  electrical condition of the earth I observed that sensitive receiving&#xA;  instruments arranged so as to be capable of responding to electrical&#xA;  disturbances created by the discharges at times failed to respond when&#xA;  they should have done so, and upon inquiring into the causes of this&#xA;  unexpected behavior I discovered it to be due to the character of the&#xA;  electrical waves which were produced in the earth by the lightning&#xA;  discharges and which had nodal regions fo&lt;em&gt;llowing at definite distances&#xA;  the shifting source of the disturbances. From data obtained in a large&#xA;  number of observations of the maxima and minima of these waves I found&#xA;  their length to vary approximately from twenty-live to seventy&#xA;  kilometers, and these results and certain theoretical,deductions led&#xA;  me to the conclusion that waves of this kind may be propagated in all&#xA;  directions over the globe&lt;/em&gt; and that they may be of still more widely&#xA;  differing lengths,the extreme limits being imposed by the physical&#xA;  dimensions and properties of the earth. &lt;em&gt;Recognizing in the existence&#xA;  of these waves an unmistakable evidence that the disturbances created&#xA;  had been conducted from their origin to the most remote portions of&#xA;  the globe and had been thence reflected,&lt;/em&gt; I conceived the idea of&#xA;  producing such waves in the earth by artificial means with the object&#xA;  of utilizing them for many useful purposes for which they are or might&#xA;  be found applicable. -- &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_Nikola_Tesla_patents#Patents_#51%E2%80%93#100&quot; rel=&quot;noreferrer&quot;&gt;U.S. Patent 787,412&lt;/a&gt;&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Does Earth shows such properties? How does the Earth responds to lightning discharges? &lt;/p&gt;&#xA;" OwnerUserId="19041" LastActivityDate="2020-02-29T19:13:37.870" Title="Earth's Electricity" Tags="|earth-observation|lightning|thunderstorm|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19350" PostTypeId="1" CreationDate="2020-03-01T03:43:00.620" Score="10" ViewCount="377" Body="&lt;p&gt;Except for &lt;a href=&quot;https://www.reddit.com/r/askscience/comments/27jvt3/is_it_true_that_water_is_the_only_substance_on/&quot; rel=&quot;noreferrer&quot;&gt;ice, acetic acid, bismuth and gallium&lt;/a&gt; and a few other things materials generally shrink when they cool and solidify, so I'm pretty sure Earth has as well.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It probably wouldn't be measurable over a period of years, but models of the Earth's current and historic rates of heat flow can probably be used to estimate a rate of change of Earth's average size and possibly oblateness.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Right now &lt;a href=&quot;https://en.wikipedia.org/wiki/World_Geodetic_System#A_new_World_Geodetic_System:_WGS_84&quot; rel=&quot;noreferrer&quot;&gt;WGS84 uses&lt;/a&gt; 6378137.0 meters for Earth's equatorial radius and a flattening at the poles of about 1/298.257222. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How fast might those change over any given million years?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2021-02-26T23:52:03.523" LastActivityDate="2021-02-27T08:03:42.997" Title="How quickly is the Earth shrinking?" Tags="|geophysics|models|earth-history|thermodynamics|" AnswerCount="1" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="19351" PostTypeId="1" CreationDate="2020-03-01T12:02:58.423" Score="3" ViewCount="42" Body="&lt;p&gt;Radiolaria are microscopic marine protozoans commonly found as fossils in rocks dating as far back as the early Cambrian. Their silica skeletons are damaged by high levels of CO2, so is it possible to use this damage to assess the CO2 levels present at the time when the dead radiolarians sank into the ooze on the ocean floor?&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-03-01T12:02:58.423" Title="Use of radiolarian fossils to assess CO2 levels in early geological periods" Tags="|oceanography|rocks|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19352" PostTypeId="1" CreationDate="2020-03-01T18:03:33.067" Score="1" ViewCount="56" Body="&lt;p&gt;How can I determine the rainfall depth for an event over the watershed, if I just have two stations, S1 and S2, that are outside the catchment?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Methods I have thought of were to take the average of S1 &amp;amp; S2 or just to use the Theissen polygon method. If anyone has another idea or previous experience with this situation your help would be appreciated.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/VPKlv.jpg&quot; alt=&quot;How i can determine the rainfall depth for an event over the watershed ? If just i have S1 and S2 stations (two stations) outside the catchment.&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="19046" LastEditorUserId="2470" LastEditDate="2020-03-01T21:07:58.813" LastActivityDate="2020-03-01T21:07:58.813" Title="Rainfall guage stations outside the watershed" Tags="|hydrology|rainfall|storms|watershed|runoff|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19353" PostTypeId="2" ParentId="19334" CreationDate="2020-03-02T09:01:15.410" Score="1" Body="&lt;p&gt;Perhaps some of the oldest limestones are the banded Espanola Formation from 2.3 billion years ago. The Oxygenation of the environment happened 2.4 billion years ago. I'll find some references and chemistry info when my web connection works, here are &lt;a href=&quot;https://www.google.com/search?q=%22Espanola%20Formation%22%20limestone&amp;amp;tbm=isch&amp;amp;ved=2ahUKEwjjsvOrtfvnAhXSwYUKHdCWDkwQ2-cCegQIABAA&quot; rel=&quot;nofollow noreferrer&quot;&gt;some starter pages&lt;/a&gt;. &lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2020-03-02T10:54:08.713" LastActivityDate="2020-03-02T10:54:08.713" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19354" PostTypeId="2" ParentId="19334" CreationDate="2020-03-02T09:01:30.093" Score="4" Body="&lt;p&gt;Probably at the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hadean&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hadean&lt;/a&gt; or at the beginning of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Archean&quot; rel=&quot;nofollow noreferrer&quot;&gt;Archean&lt;/a&gt;, but there is no geological registry.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The mechanism that can lead to inorganic limestone formation is weathering of magmatic &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonatite&quot; rel=&quot;nofollow noreferrer&quot;&gt;carbonatite&lt;/a&gt; rocks. I found &lt;a href=&quot;https://www-sciencedirect-com.ezproxy.uned.es/science/article/pii/B9780124104389000133&quot; rel=&quot;nofollow noreferrer&quot;&gt;Siilinjärvi carbonatite complex&lt;/a&gt; in &lt;a href=&quot;https://en.wikipedia.org/wiki/Fennoscandia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fennoscandia&lt;/a&gt; is dated 2.6Ga (Tichomirowa et al, 2013), so Archean. It is the oldest one I found.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another mechanism that could produce limestones in ancient eons is described by user @BillDOe &lt;a href=&quot;https://earthscience.stackexchange.com/a/14357/18590&quot;&gt;in this related answer&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Once life evolved in the world's oceans, the vast majority of&#xA;  limestone formation has been through the organic process. However,&#xA;  before life did evolve, limestone formed through an inorganic process&#xA;  where rain water falling through a CO2-rich atmosphere reacted to form&#xA;  a weak carbonic acid solution that then reacted with&#xA;  calcium-containing minerals to form calcites. This then washed into&#xA;  the world's oceans to form limestone deposits.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The premise comes from &lt;a href=&quot;https://news.stanford.edu/news/2004/june2/lowegeo-62.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this stanford.edu work&lt;/a&gt; and is a bit controversial because there are no proofs limestones formed by this mechanism.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YuU9Q.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;International Stratigraphic Chart image&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;M. Tichomirowa, M.J. Whitehouse, A. Gerdes, J. Götze, B. Schulz, B.V. Belyatsky (2013): &quot;Different zircon recrystallization types in carbonatites caused by magma mixing: Evidence from U–Pb dating, trace element and isotope composition (Hf and O) of zircons from two Precambrian carbonatites from Fennoscandia&quot;, Chemical Geology, Volume 353, Pages 173-198, ISSN 0009-2541.&#xA;&lt;a href=&quot;https://doi.org/10.1016/j.chemgeo.2012.11.004&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/j.chemgeo.2012.11.004&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user18590" LastEditorDisplayName="user18590" LastEditDate="2020-03-02T19:25:09.097" LastActivityDate="2020-03-02T19:25:09.097" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="19355" PostTypeId="2" ParentId="17667" CreationDate="2020-03-02T11:59:12.157" Score="3" Body="&lt;p&gt;The region where the Earth's internal magnetic field is weakest is known as the South Atlantic Anomaly (SAA). In this region at Earth's surface, the field is approximately one third the strength of the region of maximum strength (near the North and South magnetic dip poles), so roughly 20,000nanoTesla versus 60,000nanoTesla.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The weaker field seen at Earth's surface is caused by opposite polarity field at the surface of Earth's outer core (inwards instead of outwards like in the rest of the Southern hemisphere). It allows the radiation belts closer to Earth's surface, and allows charged particles to penetrate lower into Earth's atmosphere, increasing the risk to satellites flying through the region.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oCGe2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oCGe2.png&quot; alt=&quot;The inner radiation belt is closest to Earth&amp;#39;s surface over the SAA&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:South_Atlantic_Anomaly.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source: NASA, via wikimedia&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://epod.typepad.com/.a/6a0105371bb32c970b0120a55b6770970c-pi&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://epod.typepad.com/.a/6a0105371bb32c970b0120a55b6770970c-pi&quot; alt=&quot;Electrical upsets of TOPEX/Poseidon satellite, clustered around SAA&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;a href=&quot;https://epod.usra.edu/blog/2002/06/south-atlantic-anomaly.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source: USRA&lt;/a&gt; The weaker region of field over the SAA allows the radiation belts closer to the surface, so increases the occurrence of electrical upsets (yellow dots in the image) on satellites flying through the region, here the TOPEX/Poseidon satellite. The contours are magnetic field intensity in nanoTesla.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="14123" LastEditorUserId="14123" LastEditDate="2020-03-03T17:02:54.763" LastActivityDate="2020-03-03T17:02:54.763" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19356" PostTypeId="1" AcceptedAnswerId="19364" CreationDate="2020-03-02T12:32:43.483" Score="3" ViewCount="1063" Body="&lt;p&gt;The points which, instantaneously, receive the least radiation during daylight hours must be (I assume) those that lie tangent to the Sun rays. These points rotate, so there's a whole circle of them surrounding each geographical pole. These points are not colder than the poles because (again, I assume) the radiation they receive is higher on average, although (instantaneously, during the day) the lowest anywhere on Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, the points on Earth that receive the least radiation on average must be within those circles. Which are they; are they the poles?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I should perhaps add that I am interested in the version of the problem that idealizes away from complications having to do with cloud cover or other atmospheric effects.&lt;/p&gt;&#xA;" OwnerUserId="19051" LastActivityDate="2020-03-03T09:37:54.440" Title="Which are the points on Earth that receive the least solar radiation on average?" Tags="|insolation|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19358" PostTypeId="1" CreationDate="2020-03-02T19:12:20.617" Score="4" ViewCount="105" Body="&lt;p&gt;Is there long historical data (at least a few centuries back), at the world level, of forest area? I've only found data by the FAO starting in 1990 (see &lt;a href=&quot;http://www.fao.org/state-of-forests/en/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;). There is some older evidence for a few regions and countries but no aggregate measure (for instance, see &lt;a href=&quot;https://ourworldindata.org/forests#changes-in-forest-cover-by-world-region&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;). Any help is appreciated.&lt;/p&gt;&#xA;" OwnerUserId="13541" LastActivityDate="2020-03-03T15:17:47.623" Title="Historical data on world's forest area" Tags="|forest|database|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19360" PostTypeId="1" CreationDate="2020-03-02T23:31:08.683" Score="1" ViewCount="50" Body="&lt;p&gt;If the sea level was 30000 feet, all land would be submerged and no beaches would exist.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the sea level was -30000 feet, no sea would exist and there would also be no beaches.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The beach area maximizing sea level must be between  these values. What is it?&lt;/p&gt;&#xA;" OwnerUserId="19053" LastActivityDate="2020-03-03T07:09:52.693" Title="At what sea level would beach area be maximized?" Tags="|geography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19362" PostTypeId="2" ParentId="19360" CreationDate="2020-03-03T07:00:06.290" Score="1" Body="&lt;p&gt;There are multiple ways one can look into this. For example, one simple way of increasing the length of coastline and, thus the beach area, would be to expose all of &lt;a href=&quot;https://en.wikipedia.org/wiki/Continental_shelf&quot; rel=&quot;nofollow noreferrer&quot;&gt;continental shelf&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The shelf break, where the continental shelf ends is pretty uniform globally and is in most cases at a depth of 140 m. As such, lowering water level by this amount will produce a large increase in beach areas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Alternatively, it might be possible to increase the overall length of the coast by increasing the water level by ~100 m. While here we lose a substantial amount of coast due to flooding of low-lying areas of continents, there will be substantial gains as well. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Such an increase firstly will create a lot of new inlets resulting in minor increase of coastal areas, but most importantly this will cause the water level to reach bases of several mountain ranges - Alps, Himalayas, Caucasus to name a few. This will create an extremely rugged coastline with ridiculous amount of fjords and bring huge increase to the coastline length.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The issue with the latter option is that I'm not sure how likely you are to have a 'beach' in a fjord environment or what exactly we should consider a 'beach' for the purposes of your question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In reality it's a pretty complicated question and it can only be solved by sitting down with modelling of coastline length at different water levels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT&lt;/strong&gt;: Another interesting option is to reduce water level by ~3-4 km. This will maximize the land area while maintaining water in the deep oceanic basins and at the same time the longest mountain range in the world - the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mid-ocean_ridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;mid-ocean ridge&lt;/a&gt; - will get exposed above sea level adding on to the overall coastal length.&lt;/p&gt;&#xA;" OwnerUserId="18158" LastEditorUserId="18158" LastEditDate="2020-03-03T07:09:52.693" LastActivityDate="2020-03-03T07:09:52.693" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19363" PostTypeId="1" AcceptedAnswerId="19365" CreationDate="2020-03-03T08:06:41.830" Score="3" ViewCount="694" Body="&lt;p&gt;Because I understand the mechanism of sea erosion as to take earth away from shorelines (and scatter it deep into the sea floor) and also to derive from climate crisis, I ask the following question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is sea erosion the opposite of sea level rising (or rather, an adjacent phenomenon)?&lt;/p&gt;&#xA;" OwnerDisplayName="user19055" LastEditorDisplayName="user19055" LastEditDate="2020-03-03T09:19:49.707" LastActivityDate="2020-03-03T12:29:47.790" Title="Is sea erosion the opposite of sea level rising (or rather, an adjacent phenomenon)?" Tags="|climate-change|sea-level|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19364" PostTypeId="2" ParentId="19356" CreationDate="2020-03-03T09:17:53.820" Score="9" Body="&lt;p&gt;On an average those would be the poles. As you correctly pointed out, due to the tilt of the Earth's axis, there are large areas that receive very little and sometimes no sunlight at all and those change throughout the year. But on an average, poles are the ones that get the least amount of solar radiation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example, see &lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/insolation&quot; rel=&quot;noreferrer&quot;&gt;this paper&lt;/a&gt; and in particular have a look at figures 2.6 and 2.7. The last of the two figures, which I will link here shows the graph of annual mean insolation as a function of latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fPrPX.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fPrPX.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here it's obvious that poles do receive the least amount of radiation on an average. But this is the idealized case, i.e. insolation at the top of atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the other hand, if you do take prevailing atmospheric conditions into account then it's a competition between the area between Spitzbergen and Iceland in the North and areas just off the coast of Antarctica in the South. Taken from Wikipedia article on &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_irradiance&quot; rel=&quot;noreferrer&quot;&gt;Solar Irradiance&lt;/a&gt; the top picture shows top of the atmosphere insolation and the bottom one - ground-level insolation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/th47H.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/th47H.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18158" LastEditorUserId="18158" LastEditDate="2020-03-03T09:37:54.440" LastActivityDate="2020-03-03T09:37:54.440" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19365" PostTypeId="2" ParentId="19363" CreationDate="2020-03-03T09:24:02.830" Score="5" Body="&lt;p&gt;A paper about this was published yesterday in Nature Climate Change: &lt;a href=&quot;https://doi.org/10.1038/s41558-020-0697-0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sandy coastlines under threat of erosion&lt;/a&gt; (Vousdoukas et al. 2020).&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;While shoreline change can be the combined result of a wide range of potentially erosive or accretive factors, there is a clear cause and effect relationship between increasing sea levels and shoreline retreat, pointing to increased coastal erosion issues. Climate change will also affect waves and storm surges, which are important drivers of coastal morphology.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The study computes projections of shoreline retreat. They computed four projections: two for 2050, and two for 2100, depending on climate change scenarios (RCP 4.5 and RCP 8.5). Here are the results:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Assuming that there are no physical limits in potential coastal retreat, by mid-century we project a probable (5th–95th percentile) global average long-term shoreline change, ranging from –78.1 to –1.1 m and –98.1 to 0.3 m, under RCP 4.5 and RCP 8.5, respectively (negative values express erosion). By the end of the century the erosive trend becomes even more dominant and we project a probable range from –164.2 to –14.8 m and –240 to –35.3 m under RCP 4.5 and RCP 8.5, respectively.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;And here is how it looks on a map (their figure 1):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tOrsL.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tOrsL.png&quot; alt=&quot;Vousdoukas 2020 figure 1&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The caption reads: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Projected long-term shoreline changes. a–d, Projected shoreline&#xA;  changes by the years 2050 (a,c) and 2100 (b,d) under RCP 4.5 (a,b) and&#xA;  RCP 8.5 (c,d). Values represent the median change and&#xA;  positive/negative values, respectively, express accretion/erosion in&#xA;  metres, relative to 2010. The global average median change is shown in&#xA;  the inset text for each case, along with the 5th–95th percentile&#xA;  range.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Note that this projected retreat is a combination of two factors: the ambient shoreline change (AC) driven by geological, anthropogenic and other physical factors, and the shoreline retreat due to sea level rise (R). But R is the dominant factor, with a worldwide contribution of 82 % to the total retreat (with regional variations, see their figure 2).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In summary, climate change leads to sea level rise, which in turns leads to coastline erosion. &lt;strong&gt;Sea erosion is not the opposite of sea level rising, it is a direct consequence of it&lt;/strong&gt;.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2020-03-03T12:25:45.593" LastActivityDate="2020-03-03T12:25:45.593" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19366" PostTypeId="2" ParentId="19363" CreationDate="2020-03-03T12:29:47.790" Score="0" Body="&lt;p&gt;There are a few facts I would like to bring to your attention. Sometimes a rising shoreline is due not only to rising sea levels but also to the land sinking. Southern England is very gradually sinking due to a seesaw effect caused by the rise of Scotland after the ice sheets melted. There are other phenomena which sometimes cause the land to rise, usually phenomena of a volcanic nature. Land has been rising around Vesuvius, for example. Earthquakes can cause it to sink. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;When land sinks or sea level rises, a new area of land is exposed to coastal erosion. In most places it would have to be a very large rise to allow the sea to go far inland. Coastal erosion is not always loss. While some of the rocks and sediments are dragged into deep water and lost, it is often the case that substantial quantities are moved further along the coast, where the current slows down and deposits it, building up new land. This happens in Britain and no doubt in other countries too.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-03-03T12:29:47.790" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19367" PostTypeId="1" CreationDate="2020-03-03T14:33:33.270" Score="2" ViewCount="102" Body="&lt;p&gt;Something that I've wondered for a while now - When continents collide, how much of the landmass gets distorted by the collision before it settles?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To perhaps give a clearer idea of what I'm talking about, I'll use an example - How much of the Indian Plate is still intact, and how much is now either driven under the Eurasian Plate or contorted into a different shape i.e. the Himalayas?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any answers would be greatly appreciated&lt;/p&gt;&#xA;" OwnerUserId="14814" LastEditorUserId="2470" LastEditDate="2020-03-08T05:56:35.313" LastActivityDate="2020-03-08T05:56:35.313" Title="Amount of Distortion at Continental Collisions" Tags="|plate-tectonics|continental-crust|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19368" PostTypeId="2" ParentId="19358" CreationDate="2020-03-03T15:17:47.623" Score="6" Body="&lt;p&gt;When I need data about past and future projected land use change, I usually refer to the global dataset that was developed for the global climate simulations CMIP6. &#xA;The dataset is the Land Use Harmonization V.2 &lt;a href=&quot;https://luh.umd.edu/&quot; rel=&quot;noreferrer&quot;&gt;LUHv2&lt;/a&gt; and it was developed by researchers at the &lt;a href=&quot;https://geog.umd.edu/facultyprofile/hurtt/george&quot; rel=&quot;noreferrer&quot;&gt;University of Maryland&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reading the &lt;a href=&quot;https://gsweb1vh2.umd.edu/LUH2/LUH2_v2h_README.pdf&quot; rel=&quot;noreferrer&quot;&gt;supporting document&lt;/a&gt; of the dataset, among others, the following characteristics are reported:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;ul&gt;&#xA;  &lt;li&gt;global domain;&lt;/li&gt;&#xA;  &lt;li&gt;850­‐2100 annual land-use states, transitions, and gridded mgt layers;&lt;/li&gt;&#xA;  &lt;li&gt;0.25 x 0.25 degree spatial resolution;&lt;/li&gt;&#xA;  &lt;li&gt;12 possible land-­use states including separation of Primary and Secondary natural  vegetation into Forest and Non‐forest sub-­types,&#xA;  Pasture into Managed Pasture and  Rangeland, and Cropland into&#xA;  multiple crop functional types&lt;/li&gt;&#xA;  &lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The dataset is composed of a set of simulations using different land surface models:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;These datasets are being developed as a contribution of the Land-Use&#xA;  Model Intercomparison Project (&lt;a href=&quot;http://www.cesm.ucar.edu/projects/CMIP6/LUMIP/&quot; rel=&quot;noreferrer&quot;&gt;LUMIP&lt;/a&gt;) to the Forcing Group for CMIP6&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Data can be downloaded from &lt;a href=&quot;https://luh.umd.edu/data.shtml&quot; rel=&quot;noreferrer&quot;&gt;this page&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, the layers you find here are &quot;just&quot; models' results, but as much as past observations made a good calibration possible, the variations reported are likely be the most accurate information about the evolution of the world forested areas currently available.&lt;/p&gt;&#xA;" OwnerUserId="8087" LastActivityDate="2020-03-03T15:17:47.623" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19369" PostTypeId="1" AcceptedAnswerId="19370" CreationDate="2020-03-03T18:48:27.697" Score="24" ViewCount="4116" Body="&lt;p&gt;I was using this website for weather conditions around the world called Ventusky (&lt;a href=&quot;https://www.ventusky.com/&quot; rel=&quot;noreferrer&quot;&gt;https://www.ventusky.com/&lt;/a&gt;) and one of its features allows you to view SO&lt;sub&gt;2&lt;/sub&gt; concentration. I stumbled upon this high concentration of SO&lt;sub&gt;2&lt;/sub&gt; near Zhezkazgan in Kazakhstan (&lt;a href=&quot;https://www.ventusky.com/?p=47.47;65.97;6&amp;amp;l=so2&quot; rel=&quot;noreferrer&quot;&gt;https://www.ventusky.com/?p=47.47;65.97;6&amp;amp;l=so2&lt;/a&gt;). I googled it but couldn't find anything. Satellite images show desert and mountains. Any ideas what could this be?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Images:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xP20z.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xP20z.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jyNUw.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jyNUw.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="19057" LastEditorUserId="595" LastEditDate="2020-03-04T09:48:33.777" LastActivityDate="2020-03-04T09:48:33.777" Title="What's causing this high SO2 concentrations in Kazakhstan?" Tags="|air-pollution|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19370" PostTypeId="2" ParentId="19369" CreationDate="2020-03-03T19:59:56.330" Score="29" Body="&lt;p&gt;The source of SO&lt;sub&gt;2&lt;/sub&gt; is the smelter associated with the &lt;a href=&quot;https://en.wikipedia.org/wiki/Jezkazgan&quot; rel=&quot;noreferrer&quot;&gt;Jezkazgan&lt;/a&gt; (Zhezkazgan, Жезказган) &lt;a href=&quot;https://www.australianmining.com.au/features/the-possibilities-of-applying-the-technology-of-ore-caving-in-caved-in-deposits/&quot; rel=&quot;noreferrer&quot;&gt;copper mine&lt;/a&gt;, mined by &lt;a href=&quot;http://russiamining.com/mining-company-directory/KAZminerals&quot; rel=&quot;noreferrer&quot;&gt;Kaz Minerals&lt;/a&gt;. The &lt;a href=&quot;https://www.google.com/maps/place/Bozshakol+Copper+Mine/@51.8448413,74.2762165,3921m/data=!3m1!1e3!4m12!1m6!3m5!1s0x4257527d1c508407:0xcead45e101ef71b1!2sKaz+Minerals+Bozshakol+Copper+mine!8m2!3d51.8103229!4d74.2907172!3m4!1s0x42574db94835460d:0xee5b22335ffe85b1!8m2!3d51.8469867!4d74.291372&quot; rel=&quot;noreferrer&quot;&gt;complex&lt;/a&gt; also &lt;a href=&quot;http://www.sulphuric-acid.com/sulphuric-acid-on-the-web/Acid%20Plants/JSC%20Kazakhmys%20-%20Zhezkazgan.htm&quot; rel=&quot;noreferrer&quot;&gt;produces sulfuric acid&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you check for the other atmospheric pollutants with ventusky.com, you will see associated particulate matter - PM 2.5 and PM 10.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="543" LastEditDate="2020-03-04T00:46:19.547" LastActivityDate="2020-03-04T00:46:19.547" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19371" PostTypeId="2" ParentId="19367" CreationDate="2020-03-03T21:24:59.753" Score="-1" Body="&lt;p&gt;I think of the plates not as icebergs floating around in a sea but as pieces of porridge skin on the surface of gently simmering porridge, moved about by convection forces from below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Indian plate became fused with the Australian plate about 43 million years ago, so now there is only one plate, the Indo-Australian plate. Since then, the whole mass has been moving north at about 4 cm per year. A relatively small amount, perhaps a quarter of what was once the Indian plate, has crumpled against the Eurasian plate to form the Himalayas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know what the total mass of the Indo-Australian plate is, but it must be many trillions of tons. Imagine the momentum of many trillions of tons of rock moving at 3 mm per month, in addition to which there are convection forces from the mantle pushing it along! Bulldozing the Himalayas must have slowed it down a little, so 43 million years ago it was moving even faster.    &lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="6" LastEditDate="2020-03-05T09:26:26.403" LastActivityDate="2020-03-05T09:26:26.403" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19372" PostTypeId="1" AcceptedAnswerId="19374" CreationDate="2020-03-04T11:43:49.963" Score="4" ViewCount="628" Body="&lt;p&gt;I'm sorry if that is stupid question. Geology is not my thing, but I'm curios about this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let's assume that mankind has never extracted fossil fuels (or existed in the first place) and for millions of years fossil fuels just stacked up in the earth's crust. &#xA;Then, let's fast forward time absurdly huge amount of time ahead, assuming there's no astronomical catastrophes.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What will happen with the pockets of fossil fuels when they grow absurdly huge? &#xA;Would they surface earth to form seas of oil or release all the gas into atmosphere?&#xA;Or would they grow in opposite direction - to the center of earth, then what would it become?&lt;/p&gt;&#xA;" OwnerUserId="19061" LastActivityDate="2023-03-24T13:39:53.473" Title="What would happend in distant future if we didn't extract fossil fuels" Tags="|crust|gas|fossil-fuel|oil-reserves|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19374" PostTypeId="2" ParentId="19372" CreationDate="2020-03-04T14:55:47.733" Score="0" Body="&lt;p&gt;Obviously if all fossil fuels had been left in the Earth it would greatly lessen the climate warming problem. You ask what would happen to these fossil fuels in the course of time if we left them alone. The coal would remain inert and fairly well behaved; some would be exposed by erosion, but would do no harm. Some would be buried even deeper as new deposits of sediment were laid on top of them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most of the oil would remain buried out of harm's way, but some would be exposed by erosion and geological faults to form tar pits or asphalt lakes (which are both much the same thing). Oil seepages are a nuisance, because they pollute the sea and fresh water on land. Fortunately they do not occur very often. On land, the volatile fraction evaporates quickly and leaves a thick, sticky residue called tar or asphalt, the latter being slightly thicker.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Well known examples are the La Brea tar pits in Los Angeles, famous for the fossils of extinct animals trapped by the tar, and the asphalt lake in Trinidad which has long been mined for surfacing roads etc. There are several other tar pits in California, and a large asphalt lake in Venezuela.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Looking into the future, a few more oil reservoirs would be caused to leak in the course of time by geological faults, but most would stay safely in the ground. Meanwhile the old processes would be at work, transforming vegetable matter into peat, peat and wood into lignite, and lignite into coal. Plankton and vegetable matter in the ocean would form more oil reservoirs. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Present fossil fuel deposits will become buried more and more deeply in the course of millions of years, when man has vanished from the scene, with new layers of sediment and new fossil fuels laid down on top of them, but they will never be buried deep enough to reach the asthenosphere, never mind the centre of the Earth. They will just, in some cases, have another kilometre or two of rock placed on top of them.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-03-04T14:55:47.733" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19375" PostTypeId="1" CreationDate="2020-03-04T15:34:42.690" Score="1" ViewCount="396" Body="&lt;p&gt;La Brea tar pits in California are the result of ancient oil seepages and famous for the fossils of extinct animals which were trapped in the tar. The asphalt lakes in Trinidad and Venezuela are also the result of ancient oil seepages. Have fossils of any kind been found in either of them, and if not, why not?&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2020-03-04T20:13:49.943" LastActivityDate="2020-03-04T20:13:49.943" Title="Have fossils ever been found in the asphalt lakes of Trinidad and Venezuela?" Tags="|geology|minerals|fossils|asphalt-lakes|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19376" PostTypeId="2" ParentId="19375" CreationDate="2020-03-04T16:04:40.877" Score="5" Body="&lt;h3&gt;Trinidad&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;Quote from &lt;a href=&quot;https://www.smithsonianmag.com/travel/trinidad-and-tobago-nature-and-scientific-wonders-18329129/&quot; rel=&quot;noreferrer&quot;&gt;https://www.smithsonianmag.com/travel/trinidad-and-tobago-nature-and-scientific-wonders-18329129/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Quite an oddity sits in La Brea in South Trinidad—the world's largest asphalt lake. Pitch Lake, while perhaps not the most beautiful of nature's creations, is certainly an intriguing one. The 100-acre lake is believed to be 250 feet deep in the center and contains some 10 million tons of pitch. As the lake replenishes itself and turns over, artifacts both peculiar and historically significant such as a mastodon tooth, fossil remains of the giant sloth, and Amerindian artifacts have been uncovered. Mineral pools on the lake are purported to have healing properties because of their high sulphur content.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;h3&gt;Venezuela&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;One example from &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6097493/&quot; rel=&quot;noreferrer&quot;&gt;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6097493/&lt;/a&gt; is an article with the title&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Fossil snakes (Squamata, Serpentes) from the tar pits of Venezuela: taxonomic, palaeoenvironmental, and palaeobiogeographical implications for the North of South America during the Cenozoic/Quaternary boundary&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;h3&gt;Summary:&lt;/h3&gt;&#xA;&#xA;&lt;p&gt;yes, fossils have been found&lt;/p&gt;&#xA;" OwnerUserId="17730" LastActivityDate="2020-03-04T16:04:40.877" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19377" PostTypeId="1" CreationDate="2020-03-04T21:02:53.810" Score="2" ViewCount="81" Body="&lt;p&gt;It is possible to store &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; geologically similar to natural burial. But at the rate that it needs to be buried, how do we know it is economic enough that more fossil fuels wouldn't have to be burned than what can be buried at an effective rate?&lt;/p&gt;&#xA;" OwnerUserId="19066" LastActivityDate="2020-03-04T22:30:20.327" Title="CO2 Storage, it's possible, but what about" Tags="|climate|carbon|geoengineering|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19378" PostTypeId="2" ParentId="19377" CreationDate="2020-03-04T21:40:00.487" Score="1" Body="&lt;p&gt;Of course ,but it would be very expensive and there would be the earthquakes. Consider that many blame fracking for earthquakes ; fracking lasts a matter of days then pressure is released and water/oil is pumped out. To sequester CO2 would involve pumping into the same or similar formations for years, so presumably cause earthquakes. There would be some good locations where CO2 could be pumped into an oil/gas formation as the oil/gas is removed . And there are some locations where that has been done for years ( CO2 and water pumped into the formation to &quot;push&quot; out the oil).There are many possibilities but any involving the large quantities of CO2 I guess you mean, would be expensive and some groups would object to.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2020-03-04T21:40:00.487" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19379" PostTypeId="2" ParentId="19377" CreationDate="2020-03-04T22:30:20.327" Score="2" Body="&lt;p&gt;It is possible and there are several demonstration projects running. In Europe, the &lt;a href=&quot;https://www.carbfix.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;carbfix&lt;/a&gt; project quotes a price of $24.8/ton for carbon sequestration. Geothermal power is used to pump the CO2 underground, so no energy from fossil fuel is required. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are concerns about the available capacity for storage using these mechanisms, and the pumping process does trigger seismic activity (e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_sequestration&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is likely that carbon buried in geological formations will be sequestered more reliably and for longer that carbon which is simply absorbed by trees ... but there is no guarantee on that there will not be some leakage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because of these concerns, and because generating electricity from sustainable sources is cheaper than burning fossil fuels and then trying to manage the pollution, the main focus of dealing with global warming should be reduction of fossil fuel use to near zero.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There may well still be a significant role for carbon sequestration in dealing with some CO2 emissions which are difficult to avoid.&lt;/p&gt;&#xA;" OwnerUserId="17518" LastActivityDate="2020-03-04T22:30:20.327" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19380" PostTypeId="1" CreationDate="2020-03-05T00:45:36.320" Score="5" ViewCount="583" Body="&lt;p&gt;LACMA (the &lt;a href=&quot;https://en.wikipedia.org/wiki/Los_Angeles_County_Museum_of_Art&quot; rel=&quot;noreferrer&quot;&gt;Los Angeles County Museum of Art&lt;/a&gt;) is built right next to the famous La Brea Tar Pits and that keeps me up at night&lt;sup&gt;†&lt;/sup&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What is the subsurface structure like adjacent to the Lake Pit? I'm wondering if the LA County Museum of Art and other buildings near the Lake Pit could actually fall in some day. Is the museum built on bedrock and the tar pit next to it is just a small hole in it, or if &quot;the big one&quot; comes (major earthquake) could soil shift and the art museum end up submersed in tar? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;†&lt;/sup&gt;no it doesn't, drinking too much coffee keeps me up at night.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Google Maps of La Brea Tar Pit and LACMA&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0zx15.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0zx15.jpg&quot; alt=&quot;Google Maps of La Brea Tar Pit and LACMA&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ground truth: LA/Hollywood, so plastic dinosaur...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DsE3A.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DsE3A.jpg&quot; alt=&quot;Google Maps of La Brea Tar Pit and LACMA&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Jh6zF.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Jh6zF.png&quot; alt=&quot;Google Maps of La Brea Tar Pit&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2021-02-26T23:51:38.240" LastActivityDate="2021-02-26T23:51:38.240" Title="Could the LA County Museum of Art fall into the LaBrea Tar pit during an earthquake?" Tags="|structural-geology|bedrock|asphalt-lakes|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="19381" PostTypeId="1" CreationDate="2020-03-05T02:18:41.040" Score="5" ViewCount="131" Body="&lt;p&gt;I've downloaded the &lt;strong&gt;all10g&lt;/strong&gt; data from &lt;a href=&quot;https://www.ngdc.noaa.gov/mgg/topo/gltiles.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ngdc.noaa.gov/mgg/topo/gltiles.html&lt;/a&gt; &lt;br&gt;&#xA;and also the &lt;strong&gt;globedocumentationmanual.pdf&lt;/strong&gt; from the &quot;The Globe Project Report&quot; link on that page.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only relevant format info I see there is on pages#82 (the 90th page) through 85.&lt;br&gt;&#xA;Are there any other relevant pages in that manual I'm overlooking, or,&lt;br&gt;&#xA;better yet, some other more comprehensive description of the data format elsewhere?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As far as pages#82-85 is concerned...&lt;br&gt;&#xA; &amp;nbsp; &amp;nbsp; Firstly, the 16-bit little-endian stuff is no problem at all.&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&amp;nbsp; &amp;nbsp; As best I can determine, the data is organized as follows:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;   +--------------------------------------------+&#xA;   |   &amp;lt;-- 10800 cols for 90deg longitude --&amp;gt;   | ^&#xA;   |       = 30 arcsec per col resolution       | | 4800rows&#xA;   |                                      ^     | | for 40deg lat,&#xA;   |       and 4800/40 or 6000/50 is also |     | | or 6000 for 50&#xA;   |       = 30 arcsec per row resolution |     | v&#xA;   +--------------------------------------v-----+&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Is this correct? Or are we talking about some other kind of projection (e.g., mercator) of the Earth's surface onto a plane rectangular grid? And am I correct in assuming that the 10800 longitude cols, even at high latitudes, is simply a waste of space (presumably for simplicity/consistency of format)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, exactly how do you stitch the tiles together at their boundaries? For example, if you wanted to represent 0-to-90 degrees in one-degree intervals, you'd need 91 points, not 90, in order to cover both the 0 and the 90 boundary points. So the page#83 &quot;Table 3. Tile Definitions&quot;, e.g.,&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;A10G   min lat=50 max=90   min lon=-180 max=-90   &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;presumably isn't covering &lt;strong&gt;both&lt;/strong&gt; the 50 and 90 lat min/max boundary points. So which one? Or what, exactly?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt;&lt;strong&gt;Aside:&lt;/strong&gt; while rummaging through the open data sites for elevation data, I also came across&#xA;&lt;a href=&quot;https://lpdaac.usgs.gov/product_search/?keyword=Elevation&amp;amp;view=cards&amp;amp;sort=title&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://lpdaac.usgs.gov/product_search/?keyword=Elevation&amp;amp;view=cards&amp;amp;sort=title&lt;/a&gt;&#xA;(then choose NASADEM_HGT v001), which seems to be in this pretty-widely-used netcdf (or variants like netcdf4) format, which I hadn't heard of before. Its format seems to be somewhat discussed at, e.g., &lt;a href=&quot;https://www.researchgate.net/post/Extracting_data_from_a_netCDF_file&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/post/Extracting_data_from_a_netCDF_file&lt;/a&gt; (and several similar), but I haven't been able to google a nice, concise, meant-for-programmers discussion. Can you point me to one? Thanks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt; &lt;strong&gt;&amp;nbsp; &amp;nbsp; E d i t&lt;/strong&gt; &lt;br&gt; &lt;strong&gt;--------------&lt;/strong&gt; &lt;br&gt;&#xA;In response to @gerrit's reply below, I already looked over the netcdf format info, as best I could, and will maybe eventually study it more carefully. But that will clearly take lots more time (at least for me) than just dealing with the NOAA format, as discussed above.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My programming is in &lt;strong&gt;C&lt;/strong&gt;, and I've already pretty much dealt with that format, as illustrated by the gif below,&#xA;&lt;a href=&quot;https://i.stack.imgur.com/XNusz.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XNusz.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;created directly from the f10g file, just as a test.&#xA;The temporary test colors are&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;  /* --- colorkey --- */&#xA;  int colorkey[99] = {&#xA;          0*256 +  4,           /* sea surface and below is 4=blue */&#xA;        100*256 + 11,           /* up to 100m is 11=green */&#xA;        250*256 +  5,           /* up to 250m is yellow */&#xA;        500*256 + 10,           /*  500 maroon */&#xA;       1000*256 +  2,           /* 1000 red */&#xA;       2500*256 +  8,           /* 2500 gray */&#xA;      10000*256 +  9,           /* rest silver */&#xA;                  -1 };&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The eventual goal, which really isn't that much more complicated,&lt;br&gt;&#xA;is to generate a gif animation, where each successive frame shows&#xA;what happens when sea level rises, say, another foot.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In any case, a quick glance at the gif suggests that my naive interpretation of the data's lat,lon grid is, in all likelihood, generally more-or-less correct. And I probably don't need anything more accurate/precise for the intended purpose. But it would be nice (and I'd still like) to have more thorough documentation than what's cited above. Anybody have that info, or just a link to it would be great. Thanks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;br&gt; &lt;strong&gt;&amp;nbsp; &amp;nbsp; E d i t # 2&lt;/strong&gt; &lt;br&gt; &lt;strong&gt;------------------&lt;/strong&gt; &lt;br&gt;&#xA;Just to illustrate the intended use, below's an animation, focusing on the Florida region of the f10g tile. Each successive frame raises sea level (actually, lowers the elevation of each land pixel, leaving ocean unchanged) by one meter. The first frame is raw data, and there are 30 frames in all, and then repeat. Of course, one meter times 30 is kind of extreme, but the NOAA data's in meters, so I don't immediately have any finer vertical resolution available. And it's just a prototype illustration (but I know where I'm buying my retirement home:).&#xA;&lt;a href=&quot;https://i.stack.imgur.com/X5QIB.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/X5QIB.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;The colortable/colorkey is also different than the first gif above,&#xA;with light_green--&gt;dark_green for the first twelve meters, and then yellow up to 100 meters, as follows&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;  int colorkey2[99] = {&#xA;          0*256 +  0,           /* sea surface and below is 0=blue */&#xA;          1*256 +  1,           /* 1-12 meters are shades of green */&#xA;          2*256 +  2,           /*  &quot;  */&#xA;          3*256 +  3,           /*  &quot;  */&#xA;          4*256 +  4,           /*  &quot;  */&#xA;          5*256 +  5,           /*  &quot;  */&#xA;          6*256 +  6,           /*  &quot;  */&#xA;          7*256 +  7,           /*  &quot;  */&#xA;          8*256 +  8,           /*  &quot;  */&#xA;          9*256 +  9,           /*  &quot;  */&#xA;         10*256 + 10,           /*  &quot;  */&#xA;         11*256 + 11,           /*  &quot;  */&#xA;         12*256 + 12,           /*  &quot;  */&#xA;        100*256 + 13,           /*  yellow up to 100 meters */&#xA;        500*256 + 14,           /*  red 500 */&#xA;      99999*256 + 15,           /*  silver higher */&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="13783" LastEditorUserId="13783" LastEditDate="2020-03-06T13:08:04.610" LastActivityDate="2020-03-06T13:08:04.610" Title="Format/interpretation of NOAA Elevation Data" Tags="|open-data|data-formats|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19383" PostTypeId="2" ParentId="19381" CreationDate="2020-03-05T09:04:20.467" Score="4" Body="&lt;p&gt;If you can find a &lt;a href=&quot;https://en.wikipedia.org/wiki/NetCDF&quot; rel=&quot;nofollow noreferrer&quot;&gt;NetCDF&lt;/a&gt; file, I would recommend using it.  NetCDF is a very common self-documenting format with libraries widely available for any language that is suitable for scientific data analysis.  Global elevation data is commonly used and easily available. I've used the &lt;a href=&quot;https://www.ngdc.noaa.gov/mgg/global/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA ETOPO&lt;/a&gt; dataset, available as NetCDF or geotiff.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are using Python, I would recommend using &lt;a href=&quot;http://xarray.pydata.org/en/stable/&quot; rel=&quot;nofollow noreferrer&quot;&gt;xarray&lt;/a&gt;, but the lower level &lt;a href=&quot;https://unidata.github.io/netcdf4-python/netCDF4/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;netCDF4&lt;/a&gt; is also quite good.  There is also interactive software to visualise NetCDF, such as &lt;a href=&quot;https://www.giss.nasa.gov/tools/panoply/&quot; rel=&quot;nofollow noreferrer&quot;&gt;panoply&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2020-03-05T12:09:21.723" LastActivityDate="2020-03-05T12:09:21.723" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19384" PostTypeId="1" AcceptedAnswerId="19386" CreationDate="2020-03-05T09:23:27.110" Score="19" ViewCount="6065" Body="&lt;p&gt;I read the IPCC reports, I know global warming is happening and is man-made.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But as any skeptic should do periodically, I went to a few climate deniers websites and stumbled upon this peer-reviewed scientific paper, published in &quot;Journal of Atmospheric and Solar-Terrestrial Physics&quot;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S1364682618305030&quot; rel=&quot;noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/abs/pii/S1364682618305030&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The paper is coming from Costas Varotsos, a Greek physicist known from his contribution to the global climate-dynamics research and remote sensing.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The full paper is here:&#xA;&lt;a href=&quot;https://sci-hub.tw/https://doi.org/10.1016/j.jastp.2018.10.020&quot; rel=&quot;noreferrer&quot;&gt;https://sci-hub.tw/https://doi.org/10.1016/j.jastp.2018.10.020&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's too technical for me to point what the mistakes could have been made in that paper.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The only counter-argument I found on the web is a comment about it on the skepticalscience website:&#xA;&lt;a href=&quot;https://skepticalscience.com/news.php?p=3&amp;amp;t=103&amp;amp;&amp;amp;n=292#131401&quot; rel=&quot;noreferrer&quot;&gt;https://skepticalscience.com/news.php?p=3&amp;amp;t=103&amp;amp;&amp;amp;n=292#131401&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could anyone translate that comment in less technical terms for me ?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/dejsY.png&quot; alt=&quot;comment on the paper&quot;&gt;&lt;/p&gt;&#xA;" OwnerUserId="19071" LastEditorUserId="6" LastEditDate="2020-03-05T22:43:33.110" LastActivityDate="2020-03-05T22:43:33.110" Title="Debunking scientific paper &quot;Has global warming already arrived?&quot;" Tags="|climate-change|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19385" PostTypeId="1" CreationDate="2020-03-05T09:33:12.823" Score="1" ViewCount="934" Body="&lt;p&gt;Can anyone to help me?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am trying to use this command to interpolate my &lt;em&gt;netcdf&lt;/em&gt; data into my &lt;em&gt;wrfinput_d01&lt;/em&gt; .&#xA;I have used this:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;cdo remapbil,NEW_GRID_DEF old-file.nc new-file.nc&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;but I receive this massage:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;[****Warning (cdf_scan_var_attr) : Time must be the first dimension! &#xA;Unsupported array structure, skipped variable wetland_CH4_emissions!&#xA;Warning (cdf_set_var) : Inconsistent variable definition for wetland_CH4_emissions!&#xA;cdo remapbil (Abort): No remappable grid found!****][1]&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;What shall I do?&lt;/p&gt;&#xA;" OwnerUserId="18881" LastEditorUserId="5594" LastEditDate="2020-03-05T17:15:46.073" LastActivityDate="2020-03-05T17:15:46.073" Title="How can I do cdo remapbil" Tags="|meteorology|atmosphere-modelling|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19386" PostTypeId="2" ParentId="19384" CreationDate="2020-03-05T09:50:52.663" Score="35" Body="&lt;p&gt;The comment is saying that the authors are making a fallacy as follows:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Temperature increase will be associated with an increase in tropopause height.&lt;/li&gt;&#xA;&lt;li&gt;Using instrument/dataset X, we fail to measure a tropopause height increase.&lt;/li&gt;&#xA;&lt;li&gt;Therefore, there is no temperature increase.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;The fallacy here is that instrument/dataset X is not suitable to measure tropopause height, therefore one should not expect it can measure a tropopause height increase.&lt;/p&gt;&#xA;&lt;p&gt;The comment is referring to the &lt;a href=&quot;https://en.wikipedia.org/wiki/UAH_satellite_temperature_dataset&quot; rel=&quot;noreferrer&quot;&gt;University of Alabama in Huntsville temperature dataset&lt;/a&gt;.  This is derived from satellite microwave temperature sounders¹.  From the Wikipedia article, this dataset provides:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;UAH provide data on three broad levels of the atmosphere.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The Lower troposphere - TLT (originally called T2LT).&lt;/li&gt;&#xA;&lt;li&gt;The mid troposphere - TMT&lt;/li&gt;&#xA;&lt;li&gt;The lower stratosphere - TLS&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropopause&quot; rel=&quot;noreferrer&quot;&gt;tropopause&lt;/a&gt; is the boundary between troposphere and stratosphere.  It can be defined in various ways, but to measure tropopause height you generally need to measure the temperature in the vicinity to the tropopause.  As this is apparently not provided by the dataset, it is impossible to use the dataset to measure tropopause height.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;¹From personal experience, I can tell you that it is &lt;strong&gt;difficult&lt;/strong&gt; to determine long-term temperature triends from satellite data.  Polar-orbiting satellites in sun-synchronous orbits experience a drift over time, which means that their local time ascending node changes; in lay terms, this means that when they previously always passed at 14:00 over a certain spot, 2 years later this may be at 16:00.  Even if that time wouldn't change, instruments degrade over time and get replaced by new instruments.  You need to be very careful to make sure you're detecting a trend in the temperature and not in the instrument itself!  I've worked on this in the &lt;a href=&quot;https://www.fiduceo.eu&quot; rel=&quot;noreferrer&quot;&gt;FIDUCEO project&lt;/a&gt;, I was doing infrared temperature sounders and colleagues from Hamburg were doing microwave humidity sounders, but microwave temperature sounders were out of scope because none of us had the depth of expertise needed.  Even with the expertise, we underestimated the difficulty of the problem and ran out of time before we could properly declare we had delivered what had been promised to the funding agency, although we learned a lot.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-03-05T22:42:52.357" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19387" PostTypeId="2" ParentId="19380" CreationDate="2020-03-05T15:45:16.427" Score="3" Body="&lt;p&gt;The two geological faults that may be responsible of large earthquake in proximity of the museum are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Hollywood fault;&lt;/li&gt;&#xA;&lt;li&gt;Santa Monica fault (actually many branches, but they all go together as Santa Monica fault).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The museum seems to be enough far away from the fault trace (the surface expression of the fault itself), so it is unlikely that there will be a major shift in the soil. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the museum may sink in the soil due to the earthquake mobilizing the soil, especially if composed of loose sand.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The phenomena responsible of the museum &quot;falling in the soil during an earthquake&quot; is liquefaction. The geological service of California provides you an interactive map to check if a certain address may be under liquefaction hazard &lt;a href=&quot;https://www.americangeosciences.org/critical-issues/maps/interactive-map-california-earthquake-hazard-zones&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.americangeosciences.org/critical-issues/maps/interactive-map-california-earthquake-hazard-zones&lt;/a&gt; and ...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;at the moment the interactive map is not accesible to me. Sorry :) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If liquefaction is possible, either the tar may quickly move and sputter on/in the museum, or the museum may sink in and later tar may infiltrate slowly in the building.&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2020-03-05T15:45:16.427" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19388" PostTypeId="1" CreationDate="2020-03-05T16:09:42.383" Score="4" ViewCount="91" Body="&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/19363&quot;&gt;This question&lt;/a&gt; made me wonder: &lt;strong&gt;how much mass (or volume) of material is eroded by the sea each year? Of this mass, how much is deposited in the oceans?&lt;/strong&gt; (As Michael pointed out in his answer, part of the eroded material can be redeposited on another part of the shoreline.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The bottom line is: I wonder if the increase in sea level (and subsequent increase in coastal erosion) could lead to a positive feedback because of Archimedes principle. I'd like to calculate if the volume of material deposited in the oceans is enough to make the sea level rise, or if this effect is negligible.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-06-15T12:08:23.340" Title="Mass budget of coastal erosion and ocean deposion" Tags="|sea-level|sedimentology|erosion|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19389" PostTypeId="1" AcceptedAnswerId="19399" CreationDate="2020-03-05T21:40:33.963" Score="5" ViewCount="128" Body="&lt;p&gt;In the short BBC video &lt;a href=&quot;https://www.bbc.com/reel/video/p085k026/spain-s-otherworldly-red-river&quot; rel=&quot;nofollow noreferrer&quot;&gt;Spain's otherworldly red river&lt;/a&gt;, Ricardo Amils, a researcher in Spain's &lt;a href=&quot;https://en.wikipedia.org/wiki/Spanish_Astrobiology_Center&quot; rel=&quot;nofollow noreferrer&quot;&gt;Astrobiology Center&lt;/a&gt; says the following (amateur transcription):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Río Tinto is a peculiar place in our planet that has many similarities with Mars. The most important one is iron. Mars is red because of its iron, and Río Tinto is the red river.&lt;/p&gt;&#xA;&lt;p&gt;The river’s singular red colour comes from ferric ion, iron oxidised due to the river’s acidity...&lt;/p&gt;&#xA;&lt;p&gt;Considering the similar geochemistry and minerology, this place is a good analogue to Mars. Life on Mars would probably look like life here.&lt;/p&gt;&#xA;&lt;p&gt;During his trips to South America, Charles Darwin found life in extreme saline conditions. He then predicted that we would find life in the subsoil. It took us 200 years to prove him right.  If there is life on Mars, as some of us believe, it has to be in the subsoil.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;What definitely equialised Río Tinto and Mars was the discovery of jarosite in Mars.&lt;/strong&gt; This iron and potassium sulphate is produced in great quantities in Río Tinto.&lt;/p&gt;&#xA;&lt;p&gt;Upon drilling the river’s subsoil, scientists found a great variety of bacteria and microorganisms. These could thrive in extreme conditions, and need no oxygen.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Is it possible to better explain the connection (if any) between jarosite and subsoil biological activity that's hinted at by the video?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;The BBC's news videos don't always remain viewable indefinitely, so here are some screen shots for background and context. click for full size&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9NtgE.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9NtgEm.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/58FgH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/58FgHm.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/7F3k3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7F3k3m.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/PqXyx.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PqXyxm.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/74uy9.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/74uy9m.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/NsgJp.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NsgJpm.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/EzRAN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EzRANm.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/qlcE6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qlcE6m.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-03-07T09:24:02.527" Title="What is the connection (if any) between jarosite and subsoil biological activity near Spain's Río Tinto?" Tags="|mineralogy|soil|soil-science|geobiology|astrobiology|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="19390" PostTypeId="2" ParentId="19389" CreationDate="2020-03-05T23:34:22.000" Score="-4" Body="&lt;p&gt;Jarosite is formed from iron ore deposits by the oxidation of iron sulphides. It has nothing to do with the presence of life, but it forms an extreme environment that can only be tolerated by extremophiles. That is the only connection jarosite has with biological activity. The discovery of jarosite on Mars does not mean that there are likely to be microbes of any kind associated with it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Extremophiles are microbes which enjoy extreme environments: extremely cold, extremely hot, extremely acid, extremely salty, extremely radioactive and so on. Most of them don't need oxygen and many metabolise sulphur to make a living. Some like the dark ocean depths and pressures in the vicinity of black smokers (deep sea fumaroles).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some extremophiles are methanogens, that is to say their metabolism generates methane, which is why the detection of short-lived methane emissions on Mars attracted a lot of interest. A common methanogen on Earth lives in anoxic marshes, usually in woodland, where it generates marsh gas (methane). Microbes are ubiquitous on Earth, you can't get away from them. They are even found in rocks hundreds of metres below the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Today you can't really find Mars-like conditions on Earth. The two atmospheres are very different in composition, the pressure is very different, average temperatures on Mars are far colder, but four billion years ago Earth and Mars were very similar. Both had seas, a dense atmosphere composed mainly of CO2, and Mars was a lot warmer, but we don't know for sure whether life was spontaneously generated there as it was here on Earth. Probably it wasn't.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These Earth-like conditions on Mars vanished within a billion years or so, and any possibility of spontaneous generation of life from inert materials vanished with them. Meanwhile Earth's atmosphere has been greatly modified by biological activity, while that of Mars has stayed much the same except for a reduction in pressure caused by losses into space and the freezing out of some CO2 at the poles, mainly the south pole. &lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2020-03-07T09:24:02.527" LastActivityDate="2020-03-07T09:24:02.527" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19391" PostTypeId="1" AcceptedAnswerId="19392" CreationDate="2020-03-06T00:06:11.420" Score="7" ViewCount="3490" Body="&lt;p&gt;&lt;strong&gt;Sentinel-5P&lt;/strong&gt; satellite provides &lt;a href=&quot;https://sentinels.copernicus.eu/web/sentinel/technical-guides/sentinel-5p/products-algorithms&quot; rel=&quot;noreferrer&quot;&gt;high-resolution data products&lt;/a&gt; on concentration levels for several atmospheric trace gases (NO&lt;sub&gt;2&lt;/sub&gt;, SO&lt;sub&gt;2&lt;/sub&gt;, O&lt;sub&gt;3&lt;/sub&gt;&#xA;, and others), which are measured in &lt;strong&gt;mol/m&lt;sup&gt;2&lt;/sup&gt;&lt;/strong&gt; within the total or tropospheric column. Is it possible to deduce concentrations for a specific slice of the troposphere?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Namely, I'm interested to get NO&lt;sub&gt;2&lt;/sub&gt; raster to work in GIS, where each pixel of it will contain NO&lt;sub&gt;2&lt;/sub&gt; level in &lt;strong&gt;μg/m&lt;sup&gt;3&lt;/sup&gt;&lt;/strong&gt;, 0–50 meters above the ground. I've already read &lt;em&gt;Product User Information&lt;/em&gt;, &lt;em&gt;Algorithm Theoretical Basis Document&lt;/em&gt;, and &lt;em&gt;Input Output Data Definition&lt;/em&gt; related to the corresponding Sentinel-5 NO&lt;sub&gt;2&lt;/sub&gt; product. However, it didn't give me an idea of how to get μg/m&lt;sup&gt;3&lt;/sup&gt; for the near-ground level. Is it feasible at all? I guess it is, as in the &lt;a href=&quot;https://regional.atmosphere.copernicus.eu&quot; rel=&quot;noreferrer&quot;&gt;Copernicus European air quality portal&lt;/a&gt;, which uses Sentinel-5P data for the air pollution forecast, I see that they show NO&lt;sub&gt;2&lt;/sub&gt; concentrations in μg/m3.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Is there some workflow to do it?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;A screenshot from the Copernicus European air quality portal:&lt;/em&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/J79rd.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/J79rd.png&quot; alt=&quot;A screenshot from the Copernicus European air quality portal&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;P.S. I have good experience in remote sensing of land surface and geographic information systems, but I've never worked with weather/atmosphere data before.&lt;/p&gt;&#xA;" OwnerUserId="19023" LastEditorUserId="2470" LastEditDate="2020-03-06T05:41:52.190" LastActivityDate="2022-01-26T22:38:14.387" Title="Convert NO2 concentration in Sentinel-5P data from mol/m2 to μg/m3 on the ground level" Tags="|atmosphere|atmospheric-chemistry|air-pollution|satellites|weatherdata|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19392" PostTypeId="2" ParentId="19391" CreationDate="2020-03-06T09:10:27.937" Score="8" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;...measured in mol/m² within the total or tropospheric column. Is it possible to deduce concentrations for a specific slice of the troposphere?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Not really, since you have a crucial bit of information missing: the vertical distribution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Your alternatives are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Combine satellite data with a model to estimate near-surface NO₂.  The model may be able to estimate what surface conditions may be associated with what total column conditions, depending on other factors.&lt;/li&gt;&#xA;&lt;li&gt;Stick with total column data.&lt;/li&gt;&#xA;&lt;li&gt;Use a different data source, preferably ground-based measurements.  Although a limb sounder does a much better job at getting a high vertical resolution (at expense of horizontal resolution), below 50 metre is too close to the surface.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Measuring the vertical distribution with a down-looking sensor is difficult.  You can get some information with vertical sounding by having many closely-spaced channels along a spectral line, but the vertical resolution is going to be very poor, &lt;em&gt;in particular&lt;/em&gt; from space.  Vertical sounding is common practice for temperature and water vapour, but if you search for NO₂ vertical sounding, you will find mostly, probably exclusively, ground-based measurements.  I've tried to do CH₄ sounding and you're lucky if you can get 2 degrees of freedom of signal (DOFS), meaning a rough split in &quot;lower half&quot; or &quot;upper half&quot;, but usually you get much less than that:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1sFuf.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1sFuf.png&quot; alt=&quot;information content&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;em&gt;Source: &lt;a href=&quot;https://www.atmos-meas-tech.net/9/1961/2016/&quot; rel=&quot;noreferrer&quot;&gt;Holl et al., (2016)&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;TANSO-FTS is a spectrometer carried on a satellite, PEARL-FTS is a ground-based instrument looking up.  Now this was for CH₄ (not NO₂) and for a station in the Arctic at night.  Hopefully you're not trying to do this in the Arctic and not at night, so if you try to retrieve profiles from a spectrometer (AIRS, IASI, CrIS) you can do a better job, but near-surface, probably not.  Looking up, such as PEARL-FTS does, tends to be easier than looking down because you don't have a background surface to deal with.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are plenty of  &lt;a href=&quot;https://www.wmo-sat.info/oscar/gapanalyses?variable=106&quot; rel=&quot;noreferrer&quot;&gt;instruments that can retrieve NO₂ total column&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3WTRV.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3WTRV.png&quot; alt=&quot;total column from WMO Oscar&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;em&gt;Source: &lt;a href=&quot;https://www.wmo-sat.info/oscar/gapanalyses?variable=106&quot; rel=&quot;noreferrer&quot;&gt;WMO Oscar&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, to get a good quality profile from space you need a limb sounder, &lt;a href=&quot;https://www.wmo-sat.info/oscar/gapanalyses?mission=25&quot; rel=&quot;noreferrer&quot;&gt;such as these&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/drTRB.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/drTRB.png&quot; alt=&quot;limb sounders, WMO oscar&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;em&gt;Source: &lt;a href=&quot;https://www.wmo-sat.info/oscar/gapanalyses?mission=25&quot; rel=&quot;noreferrer&quot;&gt;WMO Oscar&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A limb sounder gets a much better vertical resolution, but a much worse horizontal and temporal resolution (there are no geostationary limb sounders, and the concept wouldn't make much sense).  You can find &lt;a href=&quot;https://www.researchgate.net/figure/Limb-viewing-geometry-for-a-limb-sounder-The-instrument-measures-the-radiance-emitted-by_fig9_261013184)&quot; rel=&quot;noreferrer&quot;&gt;a limb viewing geometry illustration here&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mpz17.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mpz17.png&quot; alt=&quot;limb geometry&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;em&gt;Source: &lt;a href=&quot;https://www.researchgate.net/figure/Limb-viewing-geometry-for-a-limb-sounder-The-instrument-measures-the-radiance-emitted-by_fig9_261013184)&quot; rel=&quot;noreferrer&quot;&gt;Riese et al. (2014)&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The best signal to noise ratio are from solar occultation limb sounders such as &lt;a href=&quot;https://www.wmo-sat.info/oscar/instruments/view/6&quot; rel=&quot;noreferrer&quot;&gt;ACE-FTS&lt;/a&gt;, but those can only measure at sunrise and sunset.  And close to the surface is difficult with any limb sounder, solar occultation or not, so it is unlikely that a limb sounder would even work in your case of measurements within 50 metre from the surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Depending on your scientific background, I would either look for model data or use ground-based measurements.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.atmos-meas-tech.net/9/1961/2016/&quot; rel=&quot;noreferrer&quot;&gt;Holl&lt;/a&gt;, G., Walker, K. A., Conway, S., Saitoh, N., Boone, C. D., Strong, K., &amp;amp; Drummond, J. R. (2016). Methane cross-validation between three Fourier transform spectrometers: SCISAT ACE-FTS, GOSAT TANSO-FTS, and ground-based FTS measurements in the Canadian high Arctic. Atmospheric Measurement Techniques, 9(5), 1961-1980. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Riese, M. &amp;amp; Oelhaf, H. &amp;amp; Preusse, P. &amp;amp; Blank, Joerg &amp;amp; Ern, M. &amp;amp; Friedl-Vallon, Felix &amp;amp; Fischer, H. &amp;amp; Guggenmoser, Tobias &amp;amp; Höpfner, Michael &amp;amp; Hoor, Peter &amp;amp; Kaufmann, M. &amp;amp; Orphal, Johannes &amp;amp; Ploeger, Felix &amp;amp; Spang, Reinhold &amp;amp; Suminska-Ebersoldt, O. &amp;amp; Ungermann, Jörn &amp;amp; Vogel, B. &amp;amp; Woiwode, W.. (2014). Gimballed Limb Observer for Radiance Imaging of the Atmosphere (GLORIA) scientific objectives. Atmospheric Measurement Techniques. 7. 1915-1928. 10.5194/amt-7-1915-2014. &lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2020-03-06T12:34:43.350" LastActivityDate="2020-03-06T12:34:43.350" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19393" PostTypeId="1" CreationDate="2020-03-06T12:37:07.990" Score="1" ViewCount="38" Body="&lt;p&gt;For my thesis, I model flash floods in urban areas. A book with recommended practices says to use events with a recurrence interval of 30 and 50 years. Regarding the duration of the precipitation event, it says to use a &quot;relevant duration&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now I'm wondering what &quot;relevant&quot; means, and can't find information so far. What rainfall duration should be used in urban areas, and why? In papers many use 1h events, but there is no explanation for the chosen duration. Sometimes I read 15min, sometimes 6h.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Perhaps someone can give me ideas in what situations what rainfall duration is &quot;relevant&quot;.&lt;/p&gt;&#xA;" OwnerUserId="18169" LastEditorUserId="18081" LastEditDate="2020-03-06T12:52:49.467" LastActivityDate="2020-03-06T12:52:49.467" Title="How to choose &quot;relevant&quot; precipitation durations for flash flood modelling?" Tags="|hydrology|models|rainfall|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19394" PostTypeId="1" CreationDate="2020-03-06T19:36:47.320" Score="2" ViewCount="48" Body="&lt;p&gt;Like some biodiversity indices that account for species evenness (whether it is dominated by a few species), I am wondering do meteorologists use an index to describe how even a temporal rainfall distribution is? (whether most precipitation are dominated by just a few days over a long time span). Thank you.&lt;/p&gt;&#xA;" OwnerUserId="3241" LastActivityDate="2020-03-17T12:36:37.963" Title="Is there an index that evaluate how even temporal rainfall distribution is?" Tags="|precipitation|rainfall|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19395" PostTypeId="1" CreationDate="2020-03-06T22:04:27.377" Score="1" ViewCount="186" Body="&lt;p&gt;I am working by WRF-ouput files (wrfout_d01_2016-01-16_00:00:00).&#xA;I  extracted and printed latitude and longitude data from the &quot;&lt;code&gt;wrfout_d01_2016-01-16_00:00:00&lt;/code&gt;&quot;, using the R tool.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone know why latitude and longitude data do not have a particular order and are always increasing and decreasing in ascending order?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As shown, the latitude or longitude increased and decreased? and have no regular trend?&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;[1] 12.82095 12.88860 12.95492 13.01984 13.08341 13.14562 13.20647 13.26591&#xA;13.32399 13.38069 13.43599 13.48991 13.54243 13.59355 13.64328 13.69160&#xA; [17] 13.73850 13.78400 13.82807 13.87075 13.91199 13.95181 13.99023 14.02719&#xA; [25] 14.06274 14.09683 14.12950 14.16074 14.19053 14.21889 14.24580 14.27127&#xA; [33] 14.29530 14.31786 14.33900 14.35867 14.37688 14.39365 14.40897 14.42283&#xA; [41] 14.43523 14.44618 14.45567 14.46369 14.47025 14.47537 14.47903 14.48121&#xA; [49] 14.48193 14.48121 14.47903 14.47537 14.47025 14.46369 14.45567 14.44618&#xA; [57] 14.43523 14.42283 14.40897 14.39365 14.37688 14.35867 14.33900 14.31786&#xA; [65] 14.29530 14.27127 14.24580 14.21889 14.19053 14.16074 14.12950 14.09683&#xA; [73] 14.06274 14.02719 13.99023 13.95181 13.91199 13.87075 13.82807 13.78400&#xA; [81] 1**3.73850 13.69160 13.64328 13.59355 13.54243 13.48991 13.43599 13.38069&#xA; [89] 13.32399 13.26591 13.20647 13.14562 13.08341 13.01984** 1**2.95492 12.88860&#xA; [97] 12.82095** 1**3.19722 13.26527 13.33195 13.39727 13.46122 13.52379 13.58498**&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="18881" LastEditorUserId="2470" LastEditDate="2020-03-07T02:24:35.970" LastActivityDate="2020-03-07T03:41:04.990" Title="Longitudes and latitudes are not regular in WRF-out files" Tags="|meteorology|wrf|wrf-chem|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19396" PostTypeId="1" CreationDate="2020-03-06T22:22:40.590" Score="1" ViewCount="650" Body="&lt;p&gt;What are some good ways to distinguish between Iguanodon and Maisaura fossils, or even just pictures of the two dinosaurs?&lt;/p&gt;&#xA;" OwnerUserId="19091" LastActivityDate="2020-03-06T23:47:24.200" Title="Identification of Iguanodon and Maiasaura" Tags="|fossils|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19397" PostTypeId="2" ParentId="19396" CreationDate="2020-03-06T23:47:24.200" Score="-1" Body="&lt;p&gt;The easiest way to distinguish iguanodon from maiasaura is to look for iguanodon's hands, which are very peculiar indeed. The hand has five digits. The thumb has a large, prominent spike on it for defensive purposes. The three middle fingers are fused and end in hoof-like nails for walking on all fours. The fifth digit corresponding to our little finger sticks out at an angle from the others and is flexible. It is believed that this enabled it to gather food. It is apparent from these strange forefeet or hands that iguanodon, a herbivore, often stood upright like a biped.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-03-06T23:47:24.200" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19398" PostTypeId="2" ParentId="19395" CreationDate="2020-03-07T03:41:04.990" Score="4" Body="&lt;p&gt;I am not sure about your R code or your snippet of data.  However, you could do an ncdump on the file and direct the output to text to get it &quot;from the horses mouth&quot; so to speak. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In general, the lat/long export of the WRF grid will not have a linear pattern.  WRF uses a spatially projected grid, likely an equal area lambert method or something similar. The curvature of the Earth creates non-linear grid values in geographic coordinates, but the projected grid coordinates (which you can also export) are linear. See the example WRF domain below plotted in geographic coordinates.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Thha5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Thha5.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;&lt;em&gt;image credit: &lt;a href=&quot;https://www.researchgate.net/publication/233409970_An_Improved_Dynamical_Downscaling_Method_with_GCM_Bias_Corrections_and_Its_Validation_with_30_Years_of_Climate_Simulations&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zhongfeng Xu and Zong-Liang Yang&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2020-03-07T03:41:04.990" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19399" PostTypeId="2" ParentId="19389" CreationDate="2020-03-07T04:13:04.880" Score="3" Body="&lt;p&gt;From what I've read so far, it appears jarosite may not be a prerequisite for the formation of certain life forms, instead that it is &lt;a href=&quot;https://www.sigmaaldrich.com/catalog/papers/23425574&quot; rel=&quot;nofollow noreferrer&quot;&gt;produced by certain organisms&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Río Tinto (Huelva, southwestern Spain) is an extreme environment with a remarkably constant acidic pH and a high concentration of heavy metals, conditions generated by the metabolic activity of chemolithotrophic microorganisms thriving in the rich complex sulfides of the Iberian Pyrite Belt (IPB). Fungal strains isolated from the Tinto basin were characterized morphologically and phylogenetically. The strain identified as Purpureocillium lilacinum specifically induced the formation of a yellow-ocher precipitate, identified as hydronium-jarosite, an iron sulfate mineral which appears in abundance on the banks of Río Tinto. The biomineral was characterized by X-ray diffraction (XRD) and its formation was observed with high-resolution transmission electron microscopy (TEM) and scanning electron microscopy (SEM) coupled to energy-dispersive X-ray spectroscopy (EDX) microanalysis. Jarosite began to nucleate on the fungal cell wall, associated to the EPS, due to a local increase in the Fe(3+) /Fe(2+) ratio which generated supersaturation. Its formation has been also observed in non-viable cells, although with much less efficiency. The occurrence of P. lilacinum in an ecosystem with high concentrations of ferric iron and sulfates such as Río Tinto suggests that it could participate in the process of jarosite precipitation, helping to shape and control the geochemical properties of this environment.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.astrobio.net/mars/unlocking-martian-rocks/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Another reference&lt;/a&gt;, states that&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;But there is something else about jarosite that makes it interesting. One of the steps in its formation involves combining pyrite (ferrous sulfide) with oxygen. This oxidation reaction can be performed by certain &quot;rock-eating&quot; microorganisms.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;... And yet, there remains the tantalizing possibility that martian jarosite owes its existence to the martian version of rock-eating microbes. If so, remnants of these organisms may be locked in the mineral.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;... This is because jarosite on Earth is known to let all sorts of foreign elements incorporate into its crystal structure.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;including, &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;amino acids, the basic components of proteins&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5954147/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fate of Lipid Biosignatures in a Mars-Analogue Sulfur Stream&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://rruff.info/uploads/CM19_429.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Formation of Rubidium Jarosite During the Microbiological Oxidation of Ferrous Iron at Room Temperature&lt;/a&gt; &lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-03-07T04:13:04.880" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19400" PostTypeId="1" CreationDate="2020-03-07T07:37:47.587" Score="4" ViewCount="1168" Body="&lt;p&gt;I have read that the islands of Sumatra &amp;amp; Java have resulted from the subduction of oceanic crust of the Indo-Australian plate beneath the Sunda plate. I want to know whether this boundary is ocean-ocean convergence or ocean-continent convergence.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are islands of Sumatra and Java like Mariana Islands which result from the subduction of the oceanic Pacific Plate beneath the oceanic Mariana plate? Or are they like the Andean volcanic continental Arc which results from the subduction of the oceanic Nazca plate beneath the South American plate.&lt;/p&gt;&#xA;" OwnerUserId="18396" LastEditorUserId="2470" LastEditDate="2020-03-07T11:48:23.290" LastActivityDate="2021-05-03T15:05:15.560" Title="What sort of a plate is the Sunda plate?" Tags="|plate-tectonics|geomorphology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19401" PostTypeId="2" ParentId="19400" CreationDate="2020-03-07T11:19:35.300" Score="-4" Body="&lt;p&gt;The convergence of the Indo-Australian plate with the Sunda plate is an oceanic-continental convergence. The Sunda plate carries some major land masses: much of SE Asia including half of Vietnam, and Borneo (which is itself three times the size of Great Britain).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The islands of Sumatra and Java are part of what is known as the Malay Archipelago, though they belong to Indonesia, as do the Lesser Sundas to the south. They are part of the original land mass of the Sunda Plate and were once connected before sea level rise separated them. They have numerous volcanoes caused by the subducting Indo-Australian plate. Arguably, these volcanoes are gradually making them larger, which also applies to the Lesser Sundas to the south. In 1815 Tambora, on the island of Sumbawa, was the site of the largest volcanic eruption in recorded history. An even larger eruption occurred at Lake Toba on Sumatra, some 75,000 years ago.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-03-07T11:19:35.300" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19402" PostTypeId="1" AcceptedAnswerId="19406" CreationDate="2020-03-07T22:36:12.460" Score="2" ViewCount="800" Body="&lt;p&gt;I need to calculate the gps coordinates of a point &quot;North 52° West 2.67 chains&quot; from a known location. What's the process to make this calculation? If possible, start with 37N-91W.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's an answer to this on &lt;a href=&quot;https://math.stackexchange.com/questions/604324/find-a-point-n-distance-away-from-a-specified-point-in-a-given-direction&quot;&gt;Mathematics&lt;/a&gt; on a plane. That answer, plus knowing degrees/meter around my location will provide a sufficiently accurate answer for the short distances in my case. Given that, this question is probably a good candidate to be closed. &lt;/p&gt;&#xA;" OwnerUserId="13510" LastEditorUserId="13510" LastEditDate="2020-03-08T13:20:31.547" LastActivityDate="2020-03-08T18:19:11.933" Title="How to calculate gps location based on direction and distance?" Tags="|gps|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19403" PostTypeId="1" CreationDate="2020-03-08T02:29:45.787" Score="2" ViewCount="165" Body="&lt;p&gt;Wired.com's &lt;a href=&quot;https://www.wired.com/story/space-photos-of-the-week-perfectly-safe-celestial-coronas/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Space Photos of the Week: Perfectly Safe Celestial Coronas&lt;/a&gt; includes radar images of the surface of Venus taken from spacecraft in orbit around it. One of them shown below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What causes this peculiar cracking? It reminds me of ice somehow.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sczvk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sczvk.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VltUi.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VltUi.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;In 1991 NASA’s Magellan spacecraft captured the cracks and corona on the surface of Venus. You can see some younger impact craters, as well as cracks from plate tectonics; that main circular feature is a corona created by past volcanic activity.PHOTOGRAPH: NASA/JPL&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="2470" LastEditDate="2020-03-08T05:53:37.110" LastActivityDate="2020-03-09T12:05:20.477" Title="Why is Venus so cracked?" Tags="|planetary-science|structural-geology|planetary-formation|radar|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19404" PostTypeId="1" CreationDate="2020-03-08T11:32:51.570" Score="2" ViewCount="245" Body="&lt;p&gt;What proportion of Earth's internal heat is generated by tidal flexion as a result of the orbiting moon, and would it have been significantly greater four billion years ago when the moon was closer? Has it ever been enough to affect surface temperature to an easily measurable extent?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;note:&lt;/strong&gt; This is not a duplicate of the following because there are no clear, quantitative answers specifically about heat &lt;em&gt;generated by tidal flexion.&lt;/em&gt; Instead those answers focus on heat produced in the oceans.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/9816/6031&quot;&gt;Is the Earth heated up by the tides?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/17363/6031&quot;&gt;How much energy does the Moon transfer to the Earth, does this affect the Earth&amp;#39;s surface temperature?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="6031" LastEditDate="2020-03-09T12:07:05.150" LastActivityDate="2020-03-11T15:29:49.527" Title="What has been the influence of the moon on Earth's temperature?" Tags="|temperature|earth-history|tides|moon|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19405" PostTypeId="2" ParentId="8318" CreationDate="2020-03-08T13:03:02.457" Score="4" Body="&lt;p&gt;The returned energy which is measured by the radar is given by the so-called &amp;quot;radar equation&amp;quot; which states that:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$P_r=\frac{CK_w^2}{r^2}\sum_{i=1}^Nn_iD_i^6$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; is &amp;quot;just&amp;quot; some antenna characteristics and &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; is the distance from the radar.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$K_w$&lt;/span&gt; is the dielectric constant, which differs for rain and snow. For rain it is approximately 0.93. For snow, &lt;span class=&quot;math-container&quot;&gt;$K_w$&lt;/span&gt; varies much more depending on type of snow i.e. wet or dry snow. So that is the first thing that complicates things when it comes to snow.&lt;/p&gt;&#xA;&lt;p&gt;Secondly, the last term, which is the reflectivity factor &lt;span class=&quot;math-container&quot;&gt;$Z=\sum_{i=1}^Nn_iD_i^6$&lt;/span&gt; also cause some trouble.&lt;/p&gt;&#xA;&lt;p&gt;There is a well known empirical formula for the relation between the reflectivity factor and the precipitation rate, &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt;, given as:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$Z=aR^b$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$a$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$b$&lt;/span&gt; are constants determined empirically. However, these are not very well determined. Fujiwara (1965) found that &lt;span class=&quot;math-container&quot;&gt;$a=450$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$b=1.48$&lt;/span&gt; for stratiform rain and &lt;span class=&quot;math-container&quot;&gt;$a=300$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$b=1.37$&lt;/span&gt; for rain showers. These &amp;quot;constants&amp;quot; are even less well-defined for snow and the many varieties that exist.&lt;/p&gt;&#xA;&lt;p&gt;To conclude I would say that while estimating the intensity of snowfall can be done, the estimation is much more uncertain than in the case of rainfall, probably making it practically useless. The main reasons are the dielectric constant and &lt;span class=&quot;math-container&quot;&gt;$a$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$b$&lt;/span&gt; in the above formula.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;And for fun:&lt;/em&gt; Plugging in numbers in the radar equation, one can see that 729 drops with a diameter of 1mm have the same reflectivity as 1 drop with a diameter of 3mm!&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Battan, L. J., &lt;em&gt;Radar observation of the atmosphere&lt;/em&gt;, p. 44-85. The University of Chicago Press, 1973.&lt;/p&gt;&#xA;&lt;p&gt;Fujiwara, M. &lt;em&gt;Raindrop-size distribution from Individual Storms&lt;/em&gt;. Journal of the atmospheric Sciences, 1965.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="17522" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-03-08T13:03:02.457" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19406" PostTypeId="2" ParentId="19402" CreationDate="2020-03-08T17:35:35.707" Score="4" Body="&lt;p&gt;The answer in a plane you linked works rather well in a sphere provided that the distance you want to measure is tiny compared with both the radius of Earth and the distance to the nearest pole - and 2.67 chains is that tiny.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For the remaining of the answer I'll be assuming that the Earth is an sphere, which quite accurate unless you need great accuracy - that is, enough accurate for nearly anything except for surveying.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The first step is to convert your distance and direction to easting and northing distances - as the linked answer tells. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The second step is to convert those two distances to degrees latitude and longitude, and you only need to know that one degree latitude measures &lt;span class=&quot;math-container&quot;&gt;$R_{Earth}\cdot\frac{\pi}{180}$&lt;/span&gt; and a degree longitude measures &lt;span class=&quot;math-container&quot;&gt;$R_{Earth}\cdot\frac{\pi}{180}\cdot cos(latitude)$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As a final step, you just need to sum those angles to the latitude and longitude of your position.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;With your data:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;&amp;gt; # Earth radius in chains&#xA;&amp;gt; (r &amp;lt;- 3958.8*80)&#xA;[1] 316704&#xA;&amp;gt; &#xA;&amp;gt; #bearing, latitude and longitude in radians&#xA;&amp;gt; (br &amp;lt;- -52/180*pi)&#xA;[1] -0.907571211&#xA;&amp;gt; (latr &amp;lt;- 37/180*pi)&#xA;[1] 0.6457718232&#xA;&amp;gt; (lonr &amp;lt;- -91/180*pi)&#xA;[1] -1.588249619&#xA;&amp;gt; &#xA;&amp;gt; #1 Distance to North and East in chains&#xA;&amp;gt; (east &amp;lt;- sin(br)*2.67)&#xA;[1] -2.103988712&#xA;&amp;gt; (north &amp;lt;- cos(br)*2.67)&#xA;[1] 1.643816139&#xA;&amp;gt; &#xA;&amp;gt; #One degree in chains&#xA;&amp;gt; (deglat &amp;lt;- r*pi/180)&#xA;[1] 5527.527554&#xA;&amp;gt; (deglon &amp;lt;- r*pi/180*cos(latr))&#xA;[1] 4414.479788&#xA;&amp;gt; &#xA;&amp;gt; #2 distance in degrees&#xA;&amp;gt; (dlat &amp;lt;- north/deglat)&#xA;[1] 0.0002973872356&#xA;&amp;gt; (dlon &amp;lt;- east/deglon)&#xA;[1] -0.000476610793&#xA;&amp;gt; &#xA;&amp;gt; #3 arriving point (GPS coordinates)&#xA;&amp;gt; (lat &amp;lt;- 37+dlat)&#xA;[1] 37.00029739&#xA;&amp;gt; (lon &amp;lt;- -91+dlon)&#xA;[1] -91.00047661&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="6550" LastEditorUserId="6550" LastEditDate="2020-03-08T18:19:11.933" LastActivityDate="2020-03-08T18:19:11.933" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19407" PostTypeId="2" ParentId="19038" CreationDate="2020-03-09T05:09:39.887" Score="6" Body="&lt;p&gt;The problem with the cancelling you suggested is that it is imposed globally for the PDE and not locally (just on the thin layer).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Usually when we talk about vertically layered media we use a plane wave &lt;span class=&quot;math-container&quot;&gt;$\exp(i(\mathbf{k}\cdot\mathbf{x}-wt))$&lt;/span&gt; trial solution (you can plug this in to confirm that it satisfies the PDE) and match boundary conditions at the interface of two layers to determine reflection and transmission coefficients. If you are not familiar with this, Aki and Richards (1980) is a good reference. See also the Zoeppritz equations &lt;a href=&quot;https://en.wikipedia.org/wiki/Zoeppritz_equations&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Zoeppritz_equations&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Introducing a very thin, stiff layer is equivalent to placing a 0 displacement (Dirichlet) boundary condition at the location of the layer. Physically, this models an infinite impedance reflector and will generate a total reflection. Waves on a string with both ends fixed are modeled in the same way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Setting vertical derivatives in displacement to 0 is imposing a Neumann B.C. on the location of the thin layer. This is exactly how the free surface is modeled. Physically, this models vanishing vertical tractions at the boundary location. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, if you want to model seismic wave propagation with an extremely stiff layer, then use the Dirichelet 0 displacement boundary condition. If the thin layer is only 'very stiff', use the reflection and transmission coefficients provided by the Zoeppritz equations. If you want tractions to disappear, use the Neumann boundary conditions. But, beware; this doesn't make physical sense if the thin layer is sandwiched between two other layers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this helps. &#xA;-D&lt;/p&gt;&#xA;" OwnerUserId="18386" LastActivityDate="2020-03-09T05:09:39.887" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19408" PostTypeId="1" CreationDate="2020-03-09T07:01:28.550" Score="5" ViewCount="756" Body="&lt;p&gt;I am trying to do &lt;a href=&quot;https://wiki.seg.org/wiki/Ambient_noise_tomography&quot; rel=&quot;noreferrer&quot;&gt;ambient noise tomography&lt;/a&gt; and I am quite confused on how to perform time-frequency analysis (FTAN) as shown in &lt;a href=&quot;https://oup.silverchair-cdn.com/oup/backfile/Content_public/Journal/gji/169/3/10.1111/j.1365-246X.2007.03374.x/3/169-3-1239-fig013.jpeg?Expires=1586760927&amp;amp;Signature=SO0ezeObA7uf0Eiq5cC0BEYXh~p1YePuwnwNXOH9De-HgSe7NesNsxk-rAGHsMOpPJ9cfH9QisyQv47kkQnE0SnEpiR3Ukq3uigpo4BhKpSwAduFX4aLnjDhEeCbpEpjxkMYQu1-dEsJRHWQg~1V8GDNHqadL8rSoGX0zVYUe2K02z-mrw0xTKaSiffs-~1uR21gUjsENiDwFtinLKHIowG84nG3fmeQB5Ys-H01YUAkIx0IJ9dio3mXgfZ9AcG10WYzcrE-TaeB~F4huYhJsLErCLNOHzuPjG-ikXHXRh~xvmGcTS6Dfek0mPIrhRWlJg6kGZ118EbcGFJM4LdXJg__&amp;amp;Key-Pair-Id=APKAIE5G5CRDK6RD3PGA&quot; rel=&quot;noreferrer&quot;&gt;figure 13b and 13d&lt;/a&gt; of &lt;a href=&quot;https://academic.oup.com/gji/article/169/3/1239/626431&quot; rel=&quot;noreferrer&quot;&gt;this paper by Bensen et al.&lt;/a&gt;. I am using Python and Obspy to do analysis. The closest I can find is &lt;a href=&quot;https://docs.obspy.org/packages/autogen/obspy.signal.tf_misfit.plot_tfr.html#obspy.signal.tf_misfit.plot_tfr&quot; rel=&quot;noreferrer&quot;&gt;time-frequency representation&lt;/a&gt; from Obspy but I'm not sure if they show the same thing. My question is how can I make similars FTAN figures from a signal?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any help would be appreciated. Thank you.&lt;/p&gt;&#xA;" OwnerUserId="19096" LastActivityDate="2021-06-30T15:58:42.490" Title="Performing time-frequency analysis (FTAN)" Tags="|geophysics|seismology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19409" PostTypeId="2" ParentId="8188" CreationDate="2020-03-09T09:40:54.833" Score="1" Body="&lt;p&gt;According to the WMO, your answer is as follows. (Note that you can use the width of your little finger held at arms length to estimate one degree and the width of three  fingers held together at arms length to estimate five degrees.) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Altocumulus is distinguished from Stratocumulus by: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Most of the regularly arranged elements having, when observed at an&#xA;  angle of more than 30° above the horizon, an apparent width between 1&#xA;  and 5°&lt;br&gt;&#xA;  Absence of any precipitation; Stratocumulus can have weak falls&#xA;  of rain, snow or snow pellets&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Or...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Stratocumulus is distinguished from Altocumulus by:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Most of the regularly arranged elements having, when observed at an&#xA;  angle of more than 30° above the horizon, an apparent width greater&#xA;  than 5°&lt;br&gt;&#xA;  Possible precipitation in the form of weak falls of rain or&#xA;  snow&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="15338" LastEditorUserId="18081" LastEditDate="2020-03-09T10:41:24.100" LastActivityDate="2020-03-09T10:41:24.100" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19410" PostTypeId="2" ParentId="19403" CreationDate="2020-03-09T11:46:43.080" Score="2" Body="&lt;p&gt;I found the picture with a small write up &lt;a href=&quot;https://www2.jpl.nasa.gov/magellan/image15.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;on a JPL site&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It's a picture of the Aine Corona with pancake domes.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;P-38340 MGN-48&#xA;  5/21/91 &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;This Magellan radar image shows a region approximately 300 kilometers (180 miles) across, centered on 59 degrees south latitude, 164 degrees east longitude and located in a vast plain to the south of Aphrodite Terra. The data for this image were obtained in January 1991.The large circular structure near the center of the image is a corona, approximately 200 kilometers in diameter and provisionally named Aine Corona. Just north of Aine Corona is one of the flat-topped volcanic constructs known as &quot;pancake&quot; domes for their shape and flap-jack appearance. This pancake dome is about 35 kilometer (21 miles) in diameter and is thought to have formed by the eruption of an extremely viscous lava. Another pancake dome is located inside the western part of the annulus of the corona fractures. Complex fracture patterns like the one in the upper right of the image are often observed in association with coronae and various volcanic features. They are thought to form because magma beneath the surface follows pre-existing fracture patterns. When eruptions or other movements of the magma occur, the magma drains from the fractures and the overlying surface rock collapses. Other volcanic features associated with Aine Corona include a set of small domes, each less than 10 kilometers (6 miles) across, located along the southern portion of the annulus of fractures, and a smooth, flat region in the center of the corona, probably a relatively young lava flow. The range of volcanic features associated with coronae suggests that volcanism plays a significant role in the formation of coronae. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.astronomynotes.com/solarsys/s8b.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Apparently&lt;/a&gt;, pan cake domes are on &lt;a href=&quot;https://en.wikipedia.org/wiki/Pancake_dome&quot; rel=&quot;nofollow noreferrer&quot;&gt;found on Venus&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2020-03-09T12:05:20.477" LastActivityDate="2020-03-09T12:05:20.477" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19412" PostTypeId="1" AcceptedAnswerId="19478" CreationDate="2020-03-09T19:18:55.410" Score="5" ViewCount="2215" Body="&lt;p&gt;Radar is a common tool in remote sensing, it is a so-called active instrument, hence it emits and receives energy.  Modern Syntethic Aperture Radar (SAR) systems are capable of both transmitting and receiving polarized waves. The most common polarizations are horizontal &lt;span class=&quot;math-container&quot;&gt;$(H)$&lt;/span&gt; and vertical &lt;span class=&quot;math-container&quot;&gt;$(V)$&lt;/span&gt; polarization, although other ones exist. Using H and V leads to 4 possible combinations of emitting and receiving signals: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$HH, VV, HV, VH,$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;which is read as transmitted first, received later (i.e. &lt;span class=&quot;math-container&quot;&gt;$HV$&lt;/span&gt; means transmitting horizontally polarized waves and receiving only vertical polarized waves).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I can relatively easily imagine the use of the &lt;span class=&quot;math-container&quot;&gt;$HH$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$VV$&lt;/span&gt; copolarized waves. They should be easier reflected by object that have a longish geometric structure. Large &lt;span class=&quot;math-container&quot;&gt;$VV$&lt;/span&gt; and small &lt;span class=&quot;math-container&quot;&gt;$HH$&lt;/span&gt; would probably indicate tower-like structures and small &lt;span class=&quot;math-container&quot;&gt;$VV$&lt;/span&gt; and large &lt;span class=&quot;math-container&quot;&gt;$HH$&lt;/span&gt; should indicate bridge-like structures.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However it is not obvious to me what structure would reflect a cross-polarized wave &lt;span class=&quot;math-container&quot;&gt;$HV$&lt;/span&gt; or &lt;span class=&quot;math-container&quot;&gt;$VH$&lt;/span&gt; stronger than &lt;span class=&quot;math-container&quot;&gt;$HH$&lt;/span&gt; or &lt;span class=&quot;math-container&quot;&gt;$VV$&lt;/span&gt;? Furthermore, what is the difference between an object that reflects &lt;span class=&quot;math-container&quot;&gt;$VH$&lt;/span&gt; and an object that reflects &lt;span class=&quot;math-container&quot;&gt;$HV$&lt;/span&gt;?&lt;/p&gt;&#xA;" OwnerUserId="19098" LastEditorUserId="19098" LastEditDate="2020-03-17T23:36:01.983" LastActivityDate="2020-03-21T04:06:00.697" Title="What is the use of HV or VH polarization in Radar?" Tags="|remote-sensing|earth-observation|satellites|radar|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19413" PostTypeId="2" ParentId="19404" CreationDate="2020-03-09T21:49:43.077" Score="6" Body="&lt;p&gt;The complications of calculating the moon's contributions to earth's heat budget are touched on in &lt;a href=&quot;https://link.springer.com/article/10.1007%2Fs11214-007-9225-z&quot; rel=&quot;noreferrer&quot;&gt;Emergence of a Habitable Planet (2007) by Zahnle, et.al. in Space Science Reviews&lt;/a&gt;, a paper trying to determine   when in earth's history the planet's surface would become cool enough to support life. The portion of the paper that relates to tidal heating suggests that the early moon contributed substantially to the interior heat of the earth system for about 1.2 million years, but as the moon's orbit widened, the earth cooled and solidified, and water condensed into oceans, the moon's contributions gradually became minimal.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Viscous damping of tidal motions generates heat. Therefore tidal&#xA;  heating occurs most strongly in materials that are solid but close to&#xA;  melting. This introduces the possibility of a governing feedback that&#xA;  works through the dependence of viscosity on temperature. If tidal&#xA;  dissipation exceeds what the atmosphere can radiate, the excess heat&#xA;  raises the temperature, which lowers the viscosity, which in turn&#xA;  lowers the rate of tidal dissipation. This looks like a stable&#xA;  feedback. It follows that, while tidal dissipation was important, the&#xA;  base of the mantle was solid but the rest of it was fluid, and tidal&#xA;  heating generated almost all of the thermal energy radiated to space.&#xA;  In the limit of an asymptotically thick steam atmosphere, tidal&#xA;  dissipation would have been regulated to generating heat at the&#xA;  runaway greenhouse limit of &lt;strong&gt;∼140 W/m2.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In a caption for a figure the authors also note:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Tidal heating plays an important role in prolonging the magma ocean.&#xA;  Tidal forcing wanes as the Moon evolves away from the Earth.&#xA;  Thereafter heat flow is controlled by convection of the solid mantle.&#xA;  By 4.4 Ga the global average heat flow would have been ∼0.5 W/m2.&#xA;  Later in the Hadean typical heat flows would have been 0.2–0.3 W/m2,&#xA;  not enormously larger than what they are now. For comparison heat flow&#xA;  today is 0.065 W/m2 through the continents and 0.1 W/m2 through the&#xA;  ocean crust.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2020-03-09T21:49:43.077" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19414" PostTypeId="1" CreationDate="2020-03-09T23:37:23.673" Score="3" ViewCount="305" Body="&lt;p&gt;I want to know how to calculate the number of days since an event in Earth's past, and am using the Cambrian explosion as an example.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I define a day to be one rotation of Earth with respect to the sun. The key point is that Earth's rotation has been slowing down over millions of years, so it will not be as simple as multiplying the time in years by 365.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a formula for the number of days x years ago that I can simply integrate to find the answer? Or some other way to approximate?&lt;/p&gt;&#xA;" OwnerUserId="19099" LastActivityDate="2021-08-16T08:51:09.347" Title="How many days has it been since the Cambrian explosion?" Tags="|geophysics|earth-history|measurements|mathematics|" AnswerCount="3" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="19415" PostTypeId="1" CreationDate="2020-03-10T00:03:05.380" Score="4" ViewCount="52" Body="&lt;p&gt;This winter in UK has been wet and windy but rarely below freezing. Last winter was colder with snow but less rain and wind. My storage heating seems to need to be set higher this year. I suspect the wet external walls of the building are chilled more with the wind. Or maybe more evaporation of wet external walls chills the building. Or maybe more cloud cover means less solar radiation heating the building. It's timber frame brick clad building with what I assume is reasonably ok cavity insulation.&lt;/p&gt;&#xA;" OwnerUserId="19101" LastActivityDate="2020-03-10T18:05:18.710" Title="can wet winters require more home heating than colder winters, in same place?" Tags="|meteorology|evaporation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19417" PostTypeId="2" ParentId="7033" CreationDate="2020-03-10T09:44:22.923" Score="2" Body="&lt;p&gt;Crossline coverage is 1/2 the spread width. A survey is usually designed to deliver perfectly abutted crossline coverage (overlapping the spreads as the previous correspondent said). Common midpoint (CMP) bin width is 1/2 the cable spacing and is sampled by one source-to-receiver ray path so crossline fold by definition is one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Easiest thing is to draw a diagram for yourself of a boat and spread sailing away from your page and then towards...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For example we had a recent survey with 13 cables at 75 m separation = 975 m spread width, so crossline coverage was 487.5 m and CMP bin width 37.5 m.&lt;/p&gt;&#xA;" OwnerUserId="19105" LastEditorUserId="18081" LastEditDate="2020-03-10T10:09:21.933" LastActivityDate="2020-03-10T10:09:21.933" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19418" PostTypeId="2" ParentId="19414" CreationDate="2020-03-10T11:00:31.340" Score="3" Body="&lt;p&gt;As a very rough approximation, one could start with equation (9) from Arbab (2009), &lt;a href=&quot;https://arxiv.org/abs/physics/0304093&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://arxiv.org/abs/physics/0304093&lt;/a&gt; to get the effective number of days per year:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$T_{\text{eff.}} = T_0 \left(\frac{t_0-t}{t_0} \right)^{-2.6}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;with &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt; the time difference between now and then&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$T_0 = 365.25$&lt;/span&gt; the current number of days per year &lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$t_0=(13.799 \pm 0.021) \cdot 10^9$&lt;/span&gt; the present age of the universe (from Planck Collaboration et al. (2015), &lt;a href=&quot;https://arxiv.org/abs/1502.01589&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://arxiv.org/abs/1502.01589&lt;/a&gt; )&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Assuming the Cambrian explosion happened about &lt;span class=&quot;math-container&quot;&gt;$t_c =(541 \pm 0.13) \cdot 10^6$&lt;/span&gt; years ago (from Bowring et al. (2007), &lt;a href=&quot;https://core.ac.uk/download/pdf/62875.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://core.ac.uk/download/pdf/62875.pdf&lt;/a&gt;), then the number of days since &lt;a href=&quot;https://www.wolframalpha.com/input/?i=evaluate+%E2%88%AB_0%5Ec+365.25*%281-t%2Fa%29%5E%28-2.6%29dt++at+c%3D%28541*10%5E6%29%2C+a%3D%2813.77*10%5E9%29&quot; rel=&quot;nofollow noreferrer&quot;&gt;can be approximated as&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$n = \int\limits_0^{t_c} T_0 \left(1 - \frac{t}{t_0} \right)^{-2.6} \mathrm{d}t  = \left[0.625 \cdot T_0 t_0 \left(1-\frac{t}{t_0}\right)^{-\frac{8}{5}} \right]_0^{t_c} \approx 2.1 \cdot 10^{11}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(of course one has to keep in mind that the error on this value is rather large, but to have some ballpark figure it should be good enough)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For comparison &lt;span class=&quot;math-container&quot;&gt;$t_c \cdot 365.25 = 1.98 \cdot 10^{11}$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="17730" LastEditorUserId="17730" LastEditDate="2020-03-10T17:30:27.763" LastActivityDate="2020-03-10T17:30:27.763" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19420" PostTypeId="2" ParentId="19414" CreationDate="2020-03-10T14:37:37.487" Score="5" Body="&lt;p&gt;From &lt;a href=&quot;https://physics.stackexchange.com/a/112339&quot;&gt;this answer&lt;/a&gt; a modern day is 1,7ms longer than a century ago. The data is taken from wikipedia, but it is sourced to &lt;a href=&quot;https://books.google.es/books?id=fjFVW3-LGigC&amp;amp;redir_esc=y&quot; rel=&quot;nofollow noreferrer&quot;&gt;this book&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Asuming the slowing down on earth's rotation has been constant since Cambrian, and that the sideral year duration has been constant too, it can be aproximated with a script:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;#Constants&#xA;yearsSinceCambrian = 541000000&#xA;slowDownSecondsDayEachYear = 0.000017&#xA;daysPerYearPresent = 365.25&#xA;secondsDayPresent = 86400&#xA;#Initiallizate the variable&#xA;daysSinceCambrianExplosion = 0&#xA;&#xA;#Calculate the number of days of each year&#xA;def sumYearDays(year):      &#xA;    secondsDay = secondsDayPresent - slowDownSecondsDayEachYear*year&#xA;    hoursDay = secondsDay/3600&#xA;    daysYear = daysPerYearPresent*24/hoursDay&#xA;    return daysYear&#xA;#Sum all days from Cambrian Explosion to year 0&#xA;for i in range (0,yearsSinceCambrian):&#xA;    daysSinceCambrianExplosion += sumYearDays(i)&#xA;&#xA;#Sum days since year zero&#xA;daysSinceYearZero = 737875&#xA;daysSinceCambrianExplosion += daysSinceYearZero&#xA;&#xA;#Print the result&#xA;print (str(daysSinceCambrianExplosion) + &quot; days approximately since life explosion.&quot;)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Output&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;208929424039.7131 days approximately since life explosion.&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;Said &lt;span class=&quot;math-container&quot;&gt;$2.09 \cdot 10^{11}$&lt;/span&gt; days.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know the moon has moved away since Cambrian, so I assume as a constant wich is not. There are some extra days not summed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I calculated the days the year had 510 my ago on my script and I got 406 days. In &lt;a href=&quot;https://spacemath.gsfc.nasa.gov/earth/6Page58.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this publication from NASA&lt;/a&gt; 510 million years ago the year had 424 days, apparently; 18 more days. I think they know it because of fossils. I must say if paleontologists are rigth, if you examine the table published the slowing down ratio has not been constant. Ocean basins and tectonic should influence. So I can't be sure to use 1,7ms/century is accurated for the hole serie. In the past it migth have been 1,8 or 1,9 ms/century who knows.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To estimate the epsylon of the script, you can multiply the half of the 18 extra days on Cambrian for the total years of the serie.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$9 * 541000000 = 4.9*10^9$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That would give a total of &lt;span class=&quot;math-container&quot;&gt;$2.14 \cdot 10^{11}$&lt;/span&gt; days. This is not very far from what the script calculates, so you can use it to calculate from other events, knowing it is an aproximation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The exact number of days can't be calculated, but there is not neither a exact known day when Phanerozoic started. Nobody can say the Phanerozoic started a 1st january 541002020 years ago, as assumed in the script.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I will say so &lt;a href=&quot;https://earthscience.stackexchange.com/a/19418/18590&quot;&gt;@samcarter_is_at_topanswers.xyz calcs&lt;/a&gt; should be correct and approximately &lt;span class=&quot;math-container&quot;&gt;$2.1 \cdot 10^{11}$&lt;/span&gt; days ago.&lt;/p&gt;&#xA;" OwnerDisplayName="user18590" LastEditorDisplayName="user18590" LastEditDate="2020-03-12T12:32:22.620" LastActivityDate="2020-03-12T12:32:22.620" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="19421" PostTypeId="1" CreationDate="2020-03-10T15:21:08.260" Score="4" ViewCount="318" Body="&lt;p&gt;We all know that the earth rotates every 24 hours, that it is tilted 23.5 degrees, that it circles the sun every 365 days, and that it is located approximately 148,600,000 km (92,333,000 miles) from the Sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We also know that we have 5 major circles of latitude, from north to South: the Arctic circle at 66.5 degrees north, the Tropic of Cancer at 23.5 north; the Equator at 0: the Tropic of Capricorn at 23.5 south, and the Antarctic Circle at 66.5 south.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have read previous answers regarding questions similar to mine but feel that the question(s) were perhaps misinterpreted as to meaning why isn't Earths side opposite the sun illuminated given the sun's size, so I want to be more specific.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Why isn't the side of the earth facing the sun completely illuminated by sunlight from the north to the south pole every day of the year?&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Because if the The Earths diameter is 12,740 km (7,917 miles) and the Sun's is 1,392,700 km (865,370 miles), or about 109 times greater, it would seem logical that the sun's rays would provide sunlight on the face of the Earth pointed towards the Sun, completely from the North Pole to the South Pole, and yet we know that it doesn't...  Why so? &lt;/p&gt;&#xA;" OwnerUserId="19108" LastEditorUserId="18081" LastEditDate="2020-03-10T15:58:51.113" LastActivityDate="2020-03-12T09:47:04.340" Title="Why isn't the side of the earth facing the sun completely illuminated by sunlight from the north to the south pole every day of the year?" Tags="|seasons|astronomy|" AnswerCount="4" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19422" PostTypeId="2" ParentId="19421" CreationDate="2020-03-10T16:50:28.577" Score="2" Body="&lt;p&gt;You give the answer in your question when you say the earth is tilted (on its axis). Because of this tilt, in winter the northern hemisphere is tilted away from the sun, so for a short while the north pole experiences complete darkness, while at the south pole the sun is in the sky for 24 hours a day and it is summer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the southern winter you have the same situation in reverse, and it is the north pole on which the sun never sets. That's why it's summer in the north. Because of the Earth's tilt, the south  pole is pointing away from the sun at that time of year. That is why you can't have sunshine from pole to pole every day of the year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't see what the sun's diameter has got to do with it. As seen from Earth, its diameter is tiny, regardless of the fact that it is over 860,000 miles across.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2020-03-10T23:57:12.327" LastActivityDate="2020-03-10T23:57:12.327" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19423" PostTypeId="2" ParentId="19415" CreationDate="2020-03-10T18:05:18.710" Score="1" Body="&lt;p&gt;This probably has less to do with the rain and more to do with the wind. The wind helps move the colder air that is outside into your house more easily because there is more force being exerted on your exterior walls and therefore cooler air can work its way through any small cracks. Sorta similar to the wind chill being colder on windier days. The lessened amount of sun also comes into play as even in the dead of winter it helps warm surfaces, even just a tiny amount.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Welcome to the Earth Science exchange!&lt;/p&gt;&#xA;" OwnerUserId="13660" LastActivityDate="2020-03-10T18:05:18.710" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19426" PostTypeId="1" CreationDate="2020-03-11T01:44:22.667" Score="2" ViewCount="842" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wdlDZ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wdlDZ.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;The the meta data text file that comes with Landsat scenes, contains an acquisition date and a scene center time in successive lines. I wanted to know if the image is recorded at the scene center time on the date of aquisition.&lt;/p&gt;&#xA;" OwnerUserId="14152" LastEditorUserId="14152" LastEditDate="2020-03-11T16:08:51.113" LastActivityDate="2020-12-07T15:06:55.773" Title="Landsat 8 acquisition time and date" Tags="|remote-sensing|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19427" PostTypeId="2" ParentId="19421" CreationDate="2020-03-11T02:05:18.300" Score="1" Body="&lt;p&gt;The sun does actually illuminate the earth with a disk a bit larger than if it would be a point light source. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But that extra Halo which is generated by say a ray coming off the most easterly point on the sun's apparent disk to the most westerly point on the earth lit disk and same for other points on the perimeter of the sun hitting the surface of the earth diagonally is very small, it is half of the sun's apparent angle which is near 32&quot; arcseconds.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If sun were big enough to lite up the entire face of the Earth from North Pole to South Pole it needed to be as big as to occupy a vast area in the sky as big as almost a quarter of the visible sky. 23+23=46 degrees apparent angle of view.&lt;/p&gt;&#xA;" OwnerUserId="5697" LastActivityDate="2020-03-11T02:05:18.300" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19428" PostTypeId="1" AcceptedAnswerId="19431" CreationDate="2020-03-11T03:43:22.303" Score="3" ViewCount="127" Body="&lt;p&gt;Phys.org's &lt;a href=&quot;https://phys.org/news/2020-03-earth-moon-identical-oxygen-twins.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Study suggests Earth and Moon not identical oxygen twins&lt;/a&gt; says&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;They found that the oxygen isotopic composition varied depending on the type of rock tested. This may be due to the degree of mixing between the molten Moon and vapor atmosphere following the impact. &lt;strong&gt;Oxygen isotopes from samples taken from the deep lunar mantle were the most different to oxygen isotopes from Earth&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;This data suggests that the deep lunar mantle may have experienced the least mixing and is most representative of the impactor Theia,&amp;quot; said Sharp. &amp;quot;Based on the results from our isotopic analysis, Theia would have an origin farther out from the Sun relative to Earth and shows that Theia's distinct oxygen isotope composition was not completely lost through homogenization during the giant impact.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and links to Erick J. Cano et al, &lt;a href=&quot;https://www.nature.com/articles/s41561-020-0550-0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Distinct oxygen isotope compositions of the Earth and Moon&lt;/a&gt;, Nature Geoscience (2020) which is paywalled. The abstract says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Here we present high-precision oxygen isotope analyses of a range of lunar lithologies and show that the Earth and Moon in fact have distinctly different oxygen isotope compositions.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;but &amp;quot;lithologies&amp;quot; sounds like it refers to &lt;a href=&quot;https://en.wikipedia.org/wiki/Lithosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;lithosphere&lt;/a&gt; which doesn't sound like it includes the &amp;quot;deep mantle&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; How exactly do they &lt;em&gt;take deep mantle samples from the Moon&lt;/em&gt; and get them to Earth? How deep does one have to go to reach the deep mantle? From what I remember the Apollo astronauts either simply walked around and picked rocks up, or hammered off some bits, or occasionally did some hand-drilling. They loaded about 100 kg up each time and flew them back to Earth made possible by &lt;a href=&quot;https://space.stackexchange.com/q/21293/12102&quot;&gt;throwing life-support equipment out the door&lt;/a&gt; as well as &lt;a href=&quot;https://space.stackexchange.com/a/33502/12102&quot;&gt;other less necessary items&lt;/a&gt; before takeoff. The deep mantle sounds pretty-much out of reach&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-03-11T05:18:56.297" Title="How do they get &quot;deep lunar mantle&quot; samples?" Tags="|planetary-science|mantle|moon|isotopic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19429" PostTypeId="1" CreationDate="2020-03-11T04:21:29.777" Score="2" ViewCount="52" Body="&lt;p&gt;What was the total damage of the 2019-2020 bushfires/wildfires in Australia?&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-07-28T09:42:17.243" Title="The effect of the 2019-2020 bushfires/wildfires in Australia" Tags="|atmosphere|air-pollution|wildfire|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19430" PostTypeId="2" ParentId="19429" CreationDate="2020-03-11T04:21:29.777" Score="3" Body="&lt;p&gt;The total area burned was &lt;a href=&quot;https://www.abc.net.au/news/science/2020-03-05/bushfire-crisis-five-big-numbers/12007716&quot; rel=&quot;nofollow noreferrer&quot;&gt;12.6 million hectares&lt;/a&gt;, or 126,000 square kilometers. This is equivalent to:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The US state of &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_U.S._states_and_territories_by_area&quot; rel=&quot;nofollow noreferrer&quot;&gt;North Carolina&lt;/a&gt; (125,920 sq km)&lt;/li&gt;&#xA;&lt;li&gt;The US state of New York (122,057 sq km)&lt;/li&gt;&#xA;&lt;li&gt;The US state of Mississippi (121,531 sq km)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://world.bymap.org/LandArea.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;North Korea&lt;/a&gt; (120, 408 sq km)&lt;/li&gt;&#xA;&lt;li&gt;96% of Greece (130,647 sq km)&lt;/li&gt;&#xA;&lt;li&gt;52% of the United Kingdom (241,930)&lt;/li&gt;&#xA;&lt;li&gt;36% of Germany (348,672 sq km)&lt;/li&gt;&#xA;&lt;li&gt;22% of France (549,970 sq km)&lt;/li&gt;&#xA;&lt;li&gt;45% of Ecuador (276,841 sq km)&lt;/li&gt;&#xA;&lt;li&gt;10% of South Africa (1,214,470 sq km)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.thejakartapost.com/news/2020/02/24/bushfires-burned-a-fifth-of-australias-forest-study.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;20% of Australia’s forests&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.weforum.org/agenda/2020/01/australia-bushfires-size-impact-wildlife-emissions/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nearly twice&lt;/a&gt; the size of the 2019 fires in Siberia&lt;/li&gt;&#xA;&lt;li&gt;5.5 times the size of the 2019 Amazon fires&lt;/li&gt;&#xA;&lt;li&gt;6 times the size of the 2018 California fires&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The amount of &lt;a href=&quot;https://atmosphere.copernicus.eu/wildfires-continue-rage-australia&quot; rel=&quot;nofollow noreferrer&quot;&gt;carbon dioxide emitted&lt;/a&gt; was 434 million tonnes. This equated to over three-quarters of the 532 million tonnes Australian industry emitted in 2018-19. Air quality during the fires was up to &lt;a href=&quot;https://www.canberratimes.com.au/story/6562383/air-quality-in-parts-of-canberra-20-times-above-hazardous-level/&quot; rel=&quot;nofollow noreferrer&quot;&gt;20 times higher than hazardous levels&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The smoke encircled the Earth and discolored the &lt;a href=&quot;https://www.washingtonpost.com/weather/2020/01/02/ash-covered-glaciers-toxic-amber-skies-australia-bushfire-smoke-spills-over-new-zealand/&quot; rel=&quot;nofollow noreferrer&quot;&gt;snow on the alpine regions of New Zealand leaving it caramel colored&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The number of people affected by smoke for the fires was 11.3 million, or 57 percent of the population of Australia.&lt;/p&gt;&#xA;&lt;p&gt;The estimated number of animal killed by the fires is &lt;a href=&quot;https://www.abc.net.au/news/2020-07-28/3-billion-animals-killed-displaced-in-fires-wwf-study/12497976&quot; rel=&quot;nofollow noreferrer&quot;&gt;3 billion&lt;/a&gt; (revised on 28 July 2020, from 1 billion animals, when updated information was available). The breakdown by animal type is:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;143 million mammals&lt;/li&gt;&#xA;&lt;li&gt;2.46 billion reptiles&lt;/li&gt;&#xA;&lt;li&gt;180 million birds&lt;/li&gt;&#xA;&lt;li&gt;51 million frogs&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;em&gt;28 July 2020&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Substantial summary of the fires in &lt;a href=&quot;https://en.wikipedia.org/wiki/2019%E2%80%9320_Australian_bushfire_season&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2020-07-28T09:42:17.243" LastActivityDate="2020-07-28T09:42:17.243" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19431" PostTypeId="2" ParentId="19428" CreationDate="2020-03-11T05:18:56.297" Score="2" Body="&lt;p&gt;There are three ways samples of the mantle could arrive on the surface of the Moon.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Drilling deep holes into the mantle, take a sample and send to the&#xA;surface.&lt;/li&gt;&#xA;&lt;li&gt;As ejecta from a large deep impact crater, particularly where the&#xA;crust is thin.&lt;/li&gt;&#xA;&lt;li&gt;During volcanic eruptions, the upward moving magma tears of chunks&#xA;of mantle from the walls of the volcanic &amp;quot;vent&amp;quot; and ejects pieces of&#xA;mantle embedded in the resulting lava as &lt;a href=&quot;https://en.wikipedia.org/wiki/Xenolith&quot; rel=&quot;nofollow noreferrer&quot;&gt;xenoliths&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;We know the Apollo astronauts only drilled down about 20 cm into the regolith, so there are no drilled samples of the Moon's mantle. This means that the only way we might have a sample of the mantle is by serendipitously picking up a sample from the surface after it was ejected by the other two methods.&lt;/p&gt;&#xA;&lt;p&gt;The Chinese rover Yutu, on the far side of the Moon, in the &lt;a href=&quot;https://asiatimes.com/2019/05/chinese-lunar-rover-reveals-moons-mantle/&quot; rel=&quot;nofollow noreferrer&quot;&gt;South Pole Aitken Basin&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;... which was formed by a celestial collision over four billion years ago. With a diameter of 2,500 km and a depth of about 13 km, the basin is the moon’s oldest and largest impact crater. Very large impact craters can potentially penetrate through the crust and enable probes to sample the lunar mantle.&lt;/p&gt;&#xA;&lt;p&gt;... the lunar soil at the landing area contained a large amount of olivine, low-calcium pyroxene and a small trace of high-calcium pyroxene, which are very likely from the lunar mantle.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Notice the term &amp;quot;very likely&amp;quot; near the end of that quote.&lt;/p&gt;&#xA;&lt;p&gt;If no one has ever seen it, how do we know what the lunar mantle looks like?&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The properties and composition of planetary interiors are inferred by indirect evidence.  Seismometers left on the surface by Apollo crews measured the velocity of seismic waves inside the Moon, an indirect measure of the density of the deep interior.  The density of the mantle is high enough so that common surface rocks cannot make up a significant portion of it; the rocks must contain large amounts of the minerals olivine and pyroxene.  In addition, the mantle rocks were partially melted to make the mare basalts that cover the surface in places.  The chemical composition of these lavas show they were made by melting a rock rich in magnesium and iron.  Finally, xenoliths of the Earth’s mantle are sometimes found entrained in lavas – these pieces are made up of the olivine-pyroxene rock peridotite (after the mineral olivine (the gem form is peridot) that makes up most of it.)  So the idea that the rocks of the mantle are olivine-rich is a well-grounded concept for which we have abundant independent evidence.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Concerning the &lt;a href=&quot;https://www.airspacemag.com/daily-planet/searching-for-the-moons-mantle-155803143/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Apollo samples&lt;/a&gt;,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Despite an exhaustive search of the Apollo samples, no samples of the mantle have been found, either as a fragment of basin ejecta or as a xenolith in the mare basalts.&lt;/p&gt;&#xA;&lt;p&gt;... Data from the orbiting Japanese Kaguya mission shows that olivine is present in the surface deposits of some lunar craters.&lt;/p&gt;&#xA;&lt;p&gt;... they mapped out the occurrences of these olivine deposits and found that many of them occur within the rims of large impact basins.  Based on models produced from gravity mapping, the crust of the Moon is thought to be thin here and the mantle is close to the surface.  Thus, these large impact basins could have excavated chunks of the mantle, throwing them out onto the surface of the Moon.&lt;/p&gt;&#xA;&lt;p&gt;... Why is the mineral olivine important?  Olivine is a silicate mineral rich in magnesium and iron; it forms one of the basic, silicate building blocks of the rocky planets.  In magma (liquid rock), olivine crystallizes first and its composition is a key indicator of the composition of the magma.&lt;/p&gt;&#xA;&lt;p&gt;... Being dense, crystallizing olivine would sink in the liquid magma, slowly accumulating deep in the Moon.  As the entire Moon solidified, these “cumulate” layers of olivine and other iron-rich minerals would make up the mantle.&lt;/p&gt;&#xA;&lt;p&gt;... Olivine is a very common mineral and abundant in the lunar crust.  A curious fact is that olivine grains in lunar highland rocks tend to have high amounts of calcium, a minor element but a key diagnostic of the crystallization environment.  In Earth rocks, olivine formed at depth has very low concentrations of calcium.&lt;/p&gt;&#xA;&lt;p&gt;the olivine crystals in dunite (a rock made up almost completely of olivine) from the Apollo 17 site – a sample proposed as a piece of the lunar mantle – likely came from the accumulation of crystals at a depth of only a few kilometers, far shallower than the tens of kilometers depth to the mantle.&lt;/p&gt;&#xA;&lt;p&gt;... Because the Kaguya spectral mapper is detecting only the presence of olivine, we cannot distinguish between pure olivine and olivine crystallized with plagioclase, what lunar scientists call troctolite.  Troctolite is common in the Apollo highland samples, but is a relatively rare rock on Earth.  It consists of (more or less) equal parts olivine and plagioclase, a calcium- and sodium-rich silicate mineral.  Troctolites make up some of the most deeply derived rocks found in the Apollo collections, but all studied to date seem to be of crustal, not mantle, provenance.  There is no objective evidence that the olivine seen by Kaguya is not derived from troctolites and/or dunites of crustal (not mantle) origin.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In short, the sample tested most likely wasn't from the mantle but because of mineralogical similarities it is being used as an analogue for a mantle sample.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-03-11T05:18:56.297" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19432" PostTypeId="1" AcceptedAnswerId="19435" CreationDate="2020-03-11T08:59:44.543" Score="6" ViewCount="290" Body="&lt;p&gt;I was studying a satellite map of Iceland and came across an interesting, but unnamed feature located between Vatnajökull glacier and Trölladyngja volcano (between 64°50'35&quot;N, 17°11'21&quot;W and 64°48'33&quot;N, 17°04'25&quot;W ; &lt;a href=&quot;https://www.google.com/maps/@64.8319456,-17.1420462,6217m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;link to google maps&lt;/a&gt;). It is a distinct, bright patch of land, around 6.5km across with an indentation in the center. Its color and texture are different than these of the lava field next to it and the indentation looks (to my untrained eye) more like a collapsed lava bubble than a caldera.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it a volcano or something else?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sU400.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sU400.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="19118" LastEditorUserId="2470" LastEditDate="2020-03-12T05:22:01.723" LastActivityDate="2020-03-12T05:22:01.723" Title="Geomorphological feature identification" Tags="|volcanology|geomorphology|identification-request|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19433" PostTypeId="1" CreationDate="2020-03-11T09:27:27.320" Score="1" ViewCount="102" Body="&lt;p&gt;Given that: 1) Four billion years ago Saturn was hotter and radiated strongly in the infra-red.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;. . . . . . . . . 2) Like Earth's moon, Titan was then closer to its planet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;. . . . . . . . . 3) Like Earth, Venus and Mars, Titan's atmosphere was then full of greenhouse gases.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;. . . . . . . . . 4) Like Earth, Saturn and its satellites were then closer to the sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;. . . . . . . . . 5) Like Earth, Titan was warmed by tidal forces causing flexion of the lithosphere,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;is it feasible that Titan once had seas and lakes of liquid water and Earth-like volcanoes?&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="18081" LastEditDate="2020-03-11T10:35:55.427" LastActivityDate="2020-03-11T10:35:55.427" Title="Earth-like conditions on Titan: is it feasible that Titan once had seas and lakes of liquid water?" Tags="|atmosphere|earth-history|planetary-science|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19434" PostTypeId="2" ParentId="19432" CreationDate="2020-03-11T09:56:17.773" Score="3" Body="&lt;p&gt;According to this &lt;a href=&quot;http://jardfraedikort.is/index_enska.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;geological map of iceland&lt;/a&gt; it is the Urðarháls, an interglacial shield, i.e. a &lt;strike&gt;dolomite&lt;/strike&gt; shield volcano that got scraped by glacial activity The hole in the middle is the pit crater.&#xA;You can find some cool pictures of it if you google the name with the correct icelandic letters.&lt;/p&gt;&#xA;" OwnerUserId="19119" LastEditorUserId="19119" LastEditDate="2020-03-11T10:26:48.250" LastActivityDate="2020-03-11T10:26:48.250" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19435" PostTypeId="2" ParentId="19432" CreationDate="2020-03-11T10:07:33.577" Score="6" Body="&lt;p&gt;The place is called Urðarháls. I could not find much information about it in the scientific literature... It is mentioned in &lt;a href=&quot;https://timarit.is/page/7011459#page/n15/mode/2up&quot; rel=&quot;noreferrer&quot;&gt;Sigmarsson &amp;amp; Halldórsson (2015)&lt;/a&gt;: they say it's an interglacial basaltic shield volcano, possibly associated with the Askja volcanic system. The fact that the volcano was eroded by glaciers probably explains the colour difference with the surrounding &quot;fresh&quot;, postglacial lavas.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The crater looks like a pit crater to me: it probably collapsed when lava was drained somewhere else, leaving an empty chamber beneath it. Another good example of pit crater is the Dolomieu, on Piton de la Fournaise, which collapsed in 2007. Look at &lt;a href=&quot;https://doi.org/10.1016/j.jvolgeores.2008.11.005&quot; rel=&quot;noreferrer&quot;&gt;Staudacher et al. (2009)&lt;/a&gt;: compare figure 3, before the collapse, and figure 11, after.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that the authors use the term &quot;caldera&quot;, which is loosely defined... What Wikipedia calls a &lt;a href=&quot;https://en.wikipedia.org/wiki/Caldera#Non-explosive_calderas&quot; rel=&quot;noreferrer&quot;&gt;non-explosive caldera&lt;/a&gt; would be referred to as a pit crater by some. I guess the two terms kind of overlap.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2020-03-11T10:14:42.657" LastActivityDate="2020-03-11T10:14:42.657" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19436" PostTypeId="2" ParentId="19404" CreationDate="2020-03-11T15:29:49.527" Score="2" Body="&lt;p&gt;Jeffronicus's answer appears to be a good one re the influence of lunar tidal heating on the early Earth. To answer the other question that has emerged in comments, as to what proportion of total heating is from tidal effects now, we can turn to &lt;a href=&quot;http://www.sciencedirect.com/science/article/pii/S0967063798000703&quot; rel=&quot;nofollow noreferrer&quot;&gt;Munk &amp;amp; Wunsch 1998&lt;/a&gt;. They tell us that the lunar tidal power going into earth tides (as opposed to into the sea or atmosphere) is about 170 GW.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The same paper reports that the total heat flow from the earth's interior to the surface is about 30 TW, so the proportion that comes from the moon's influence now is perhaps around half a percent.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2020-03-11T15:29:49.527" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19437" PostTypeId="1" CreationDate="2020-03-11T15:32:55.813" Score="5" ViewCount="1007" Body="&lt;p&gt;I'm trying to plot a windrose but I don't know how to get the variables ws and wd. Is there any variable in the wrf output that can be used to make a windrose?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I tried with 'wspd' et 'wdir' but I coudn't make my figure.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is my code:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt; # Open the NetCDF file&#xA;ncfile = Dataset(&quot;wrfout_d03_2017-06-17_15:00:00&quot;)&#xA;&#xA;&#xA;# Extract the pressure, geopotential height, and wind variables&#xA;&#xA;&#xA;p = getvar(ncfile, &quot;pressure&quot;)&#xA;z = getvar(ncfile, &quot;z&quot;, units=&quot;m&quot;)&#xA;u = getvar(ncfile, &quot;ua&quot;, units=&quot;m s-1&quot;)&#xA;v = getvar(ncfile, &quot;va&quot;, units=&quot;m s-1&quot;)&#xA;#wspd = getvar(ncfile, &quot;wspd_wdir&quot;, units=&quot;m s-1&quot;)[0,:]&#xA;&#xA;&#xA;&#xA;ws = getvar(ncfile, &quot;wspd&quot;)[:]&#xA;wd = getvar(ncfile, &quot;wdir&quot;)[:]&#xA;&#xA;&#xA;fig=plt.figure()&#xA;&#xA;ax = WindroseAxes.from_ax()&#xA;ax.bar(ws, wd, normed=True, opening=0.8, edgecolor='white')&#xA;ax.set_legend()&#xA;&#xA;&#xA;plt.show()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;h1&gt;This is the header of the netCDF file:&lt;/h1&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;netcdf wrfout_d03_2017-06-17_19\:05\:00 {&#xA;dimensions:&#xA;    Time = UNLIMITED ; // (1 currently)&#xA;    DateStrLen = 19 ;&#xA;    west_east = 486 ;&#xA;    south_north = 429 ;&#xA;    bottom_top = 47 ;&#xA;    bottom_top_stag = 48 ;&#xA;    soil_layers_stag = 4 ;&#xA;    west_east_stag = 487 ;&#xA;    south_north_stag = 430 ;&#xA;variables:&#xA;    char Times(Time, DateStrLen) ;&#xA;    float XLAT(Time, south_north, west_east) ;&#xA;        XLAT:FieldType = 104 ;&#xA;        XLAT:MemoryOrder = &quot;XY &quot; ;&#xA;        XLAT:description = &quot;LATITUDE, SOUTH IS NEGATIVE&quot; ;&#xA;        XLAT:units = &quot;degree_north&quot; ;&#xA;        XLAT:stagger = &quot;&quot; ;&#xA;        XLAT:coordinates = &quot;XLONG XLAT&quot; ;&#xA;    float XLONG(Time, south_north, west_east) ;&#xA;        XLONG:FieldType = 104 ;&#xA;        XLONG:MemoryOrder = &quot;XY &quot; ;&#xA;        XLONG:description = &quot;LONGITUDE, WEST IS NEGATIVE&quot; ;&#xA;        XLONG:units = &quot;degree_east&quot; ;&#xA;        XLONG:stagger = &quot;&quot; ;&#xA;        XLONG:coordinates = &quot;XLONG XLAT&quot; ;&#xA;    float LU_INDEX(Time, south_north, west_east) ;&#xA;        LU_INDEX:FieldType = 104 ;&#xA;        LU_INDEX:MemoryOrder = &quot;XY &quot; ;&#xA;        LU_INDEX:description = &quot;LAND USE CATEGORY&quot; ;&#xA;        LU_INDEX:units = &quot;&quot; ;&#xA;        LU_INDEX:stagger = &quot;&quot; ;&#xA;        LU_INDEX:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float ZNU(Time, bottom_top) ;&#xA;        ZNU:FieldType = 104 ;&#xA;        ZNU:MemoryOrder = &quot;Z  &quot; ;&#xA;        ZNU:description = &quot;eta values on half (mass) levels&quot; ;&#xA;        ZNU:units = &quot;&quot; ;&#xA;        ZNU:stagger = &quot;&quot; ;&#xA;    float ZNW(Time, bottom_top_stag) ;&#xA;        ZNW:FieldType = 104 ;&#xA;        ZNW:MemoryOrder = &quot;Z  &quot; ;&#xA;        ZNW:description = &quot;eta values on full (w) levels&quot; ;&#xA;        ZNW:units = &quot;&quot; ;&#xA;        ZNW:stagger = &quot;Z&quot; ;&#xA;    float ZS(Time, soil_layers_stag) ;&#xA;        ZS:FieldType = 104 ;&#xA;        ZS:MemoryOrder = &quot;Z  &quot; ;&#xA;        ZS:description = &quot;DEPTHS OF CENTERS OF SOIL LAYERS&quot; ;&#xA;        ZS:units = &quot;m&quot; ;&#xA;        ZS:stagger = &quot;Z&quot; ;&#xA;    float DZS(Time, soil_layers_stag) ;&#xA;        DZS:FieldType = 104 ;&#xA;        DZS:MemoryOrder = &quot;Z  &quot; ;&#xA;        DZS:description = &quot;THICKNESSES OF SOIL LAYERS&quot; ;&#xA;        DZS:units = &quot;m&quot; ;&#xA;        DZS:stagger = &quot;Z&quot; ;&#xA;    float VAR_SSO(Time, south_north, west_east) ;&#xA;        VAR_SSO:FieldType = 104 ;&#xA;        VAR_SSO:MemoryOrder = &quot;XY &quot; ;&#xA;        VAR_SSO:description = &quot;variance of subgrid-scale orography&quot; ;&#xA;        VAR_SSO:units = &quot;m2&quot; ;&#xA;        VAR_SSO:stagger = &quot;&quot; ;&#xA;        VAR_SSO:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float U(Time, bottom_top, south_north, west_east_stag) ;&#xA;        U:FieldType = 104 ;&#xA;        U:MemoryOrder = &quot;XYZ&quot; ;&#xA;        U:description = &quot;x-wind component&quot; ;&#xA;        U:units = &quot;m s-1&quot; ;&#xA;        U:stagger = &quot;X&quot; ;&#xA;        U:coordinates = &quot;XLONG_U XLAT_U XTIME&quot; ;&#xA;    float V(Time, bottom_top, south_north_stag, west_east) ;&#xA;        V:FieldType = 104 ;&#xA;        V:MemoryOrder = &quot;XYZ&quot; ;&#xA;        V:description = &quot;y-wind component&quot; ;&#xA;        V:units = &quot;m s-1&quot; ;&#xA;        V:stagger = &quot;Y&quot; ;&#xA;        V:coordinates = &quot;XLONG_V XLAT_V XTIME&quot; ;&#xA;    float W(Time, bottom_top_stag, south_north, west_east) ;&#xA;        W:FieldType = 104 ;&#xA;        W:MemoryOrder = &quot;XYZ&quot; ;&#xA;        W:description = &quot;z-wind component&quot; ;&#xA;        W:units = &quot;m s-1&quot; ;&#xA;        W:stagger = &quot;Z&quot; ;&#xA;        W:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float PH(Time, bottom_top_stag, south_north, west_east) ;&#xA;        PH:FieldType = 104 ;&#xA;        PH:MemoryOrder = &quot;XYZ&quot; ;&#xA;        PH:description = &quot;perturbation geopotential&quot; ;&#xA;        PH:units = &quot;m2 s-2&quot; ;&#xA;        PH:stagger = &quot;Z&quot; ;&#xA;        PH:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float PHB(Time, bottom_top_stag, south_north, west_east) ;&#xA;        PHB:FieldType = 104 ;&#xA;        PHB:MemoryOrder = &quot;XYZ&quot; ;&#xA;        PHB:description = &quot;base-state geopotential&quot; ;&#xA;        PHB:units = &quot;m2 s-2&quot; ;&#xA;        PHB:stagger = &quot;Z&quot; ;&#xA;        PHB:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float T(Time, bottom_top, south_north, west_east) ;&#xA;        T:FieldType = 104 ;&#xA;        T:MemoryOrder = &quot;XYZ&quot; ;&#xA;        T:description = &quot;perturbation potential temperature (theta-t0)&quot; ;&#xA;        T:units = &quot;K&quot; ;&#xA;        T:stagger = &quot;&quot; ;&#xA;        T:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float HFX_FORCE(Time) ;&#xA;        HFX_FORCE:FieldType = 104 ;&#xA;        HFX_FORCE:MemoryOrder = &quot;0  &quot; ;&#xA;        HFX_FORCE:description = &quot;SCM ideal surface sensible heat flux&quot; ;&#xA;        HFX_FORCE:units = &quot;W m-2&quot; ;&#xA;        HFX_FORCE:stagger = &quot;&quot; ;&#xA;    float LH_FORCE(Time) ;&#xA;        LH_FORCE:FieldType = 104 ;&#xA;        LH_FORCE:MemoryOrder = &quot;0  &quot; ;&#xA;        LH_FORCE:description = &quot;SCM ideal surface latent heat flux&quot; ;&#xA;        LH_FORCE:units = &quot;W m-2&quot; ;&#xA;        LH_FORCE:stagger = &quot;&quot; ;&#xA;    float TSK_FORCE(Time) ;&#xA;        TSK_FORCE:FieldType = 104 ;&#xA;        TSK_FORCE:MemoryOrder = &quot;0  &quot; ;&#xA;        TSK_FORCE:description = &quot;SCM ideal surface skin temperature&quot; ;&#xA;        TSK_FORCE:units = &quot;W m-2&quot; ;&#xA;        TSK_FORCE:stagger = &quot;&quot; ;&#xA;    float HFX_FORCE_TEND(Time) ;&#xA;        HFX_FORCE_TEND:FieldType = 104 ;&#xA;        HFX_FORCE_TEND:MemoryOrder = &quot;0  &quot; ;&#xA;        HFX_FORCE_TEND:description = &quot;SCM ideal surface sensible heat flux tendency&quot; ;&#xA;        HFX_FORCE_TEND:units = &quot;W m-2 s-1&quot; ;&#xA;        HFX_FORCE_TEND:stagger = &quot;&quot; ;&#xA;    float LH_FORCE_TEND(Time) ;&#xA;        LH_FORCE_TEND:FieldType = 104 ;&#xA;        LH_FORCE_TEND:MemoryOrder = &quot;0  &quot; ;&#xA;        LH_FORCE_TEND:description = &quot;SCM ideal surface latent heat flux tendency&quot; ;&#xA;        LH_FORCE_TEND:units = &quot;W m-2 s-1&quot; ;&#xA;        LH_FORCE_TEND:stagger = &quot;&quot; ;&#xA;    float TSK_FORCE_TEND(Time) ;&#xA;        TSK_FORCE_TEND:FieldType = 104 ;&#xA;        TSK_FORCE_TEND:MemoryOrder = &quot;0  &quot; ;&#xA;        TSK_FORCE_TEND:description = &quot;SCM ideal surface skin temperature tendency&quot; ;&#xA;        TSK_FORCE_TEND:units = &quot;W m-2 s-1&quot; ;&#xA;        TSK_FORCE_TEND:stagger = &quot;&quot; ;&#xA;    float MU(Time, south_north, west_east) ;&#xA;        MU:FieldType = 104 ;&#xA;        MU:MemoryOrder = &quot;XY &quot; ;&#xA;        MU:description = &quot;perturbation dry air mass in column&quot; ;&#xA;        MU:units = &quot;Pa&quot; ;&#xA;        MU:stagger = &quot;&quot; ;&#xA;        MU:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float MUB(Time, south_north, west_east) ;&#xA;        MUB:FieldType = 104 ;&#xA;        MUB:MemoryOrder = &quot;XY &quot; ;&#xA;        MUB:description = &quot;base state dry air mass in column&quot; ;&#xA;        MUB:units = &quot;Pa&quot; ;&#xA;        MUB:stagger = &quot;&quot; ;&#xA;        MUB:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float NEST_POS(Time, south_north, west_east) ;&#xA;        NEST_POS:FieldType = 104 ;&#xA;        NEST_POS:MemoryOrder = &quot;XY &quot; ;&#xA;        NEST_POS:description = &quot;-&quot; ;&#xA;        NEST_POS:units = &quot;-&quot; ;&#xA;        NEST_POS:stagger = &quot;&quot; ;&#xA;        NEST_POS:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float P(Time, bottom_top, south_north, west_east) ;&#xA;        P:FieldType = 104 ;&#xA;        P:MemoryOrder = &quot;XYZ&quot; ;&#xA;        P:description = &quot;perturbation pressure&quot; ;&#xA;        P:units = &quot;Pa&quot; ;&#xA;        P:stagger = &quot;&quot; ;&#xA;        P:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float PB(Time, bottom_top, south_north, west_east) ;&#xA;        PB:FieldType = 104 ;&#xA;        PB:MemoryOrder = &quot;XYZ&quot; ;&#xA;        PB:description = &quot;BASE STATE PRESSURE&quot; ;&#xA;        PB:units = &quot;Pa&quot; ;&#xA;        PB:stagger = &quot;&quot; ;&#xA;        PB:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float FNM(Time, bottom_top) ;&#xA;        FNM:FieldType = 104 ;&#xA;        FNM:MemoryOrder = &quot;Z  &quot; ;&#xA;        FNM:description = &quot;upper weight for vertical stretching&quot; ;&#xA;        FNM:units = &quot;&quot; ;&#xA;        FNM:stagger = &quot;&quot; ;&#xA;    float FNP(Time, bottom_top) ;&#xA;        FNP:FieldType = 104 ;&#xA;        FNP:MemoryOrder = &quot;Z  &quot; ;&#xA;        FNP:description = &quot;lower weight for vertical stretching&quot; ;&#xA;        FNP:units = &quot;&quot; ;&#xA;        FNP:stagger = &quot;&quot; ;&#xA;    float RDNW(Time, bottom_top) ;&#xA;        RDNW:FieldType = 104 ;&#xA;        RDNW:MemoryOrder = &quot;Z  &quot; ;&#xA;        RDNW:description = &quot;inverse d(eta) values between full (w) levels&quot; ;&#xA;        RDNW:units = &quot;&quot; ;&#xA;        RDNW:stagger = &quot;&quot; ;&#xA;    float RDN(Time, bottom_top) ;&#xA;        RDN:FieldType = 104 ;&#xA;        RDN:MemoryOrder = &quot;Z  &quot; ;&#xA;        RDN:description = &quot;inverse d(eta) values between half (mass) levels&quot; ;&#xA;        RDN:units = &quot;&quot; ;&#xA;        RDN:stagger = &quot;&quot; ;&#xA;    float DNW(Time, bottom_top) ;&#xA;        DNW:FieldType = 104 ;&#xA;        DNW:MemoryOrder = &quot;Z  &quot; ;&#xA;        DNW:description = &quot;d(eta) values between full (w) levels&quot; ;&#xA;        DNW:units = &quot;&quot; ;&#xA;        DNW:stagger = &quot;&quot; ;&#xA;    float DN(Time, bottom_top) ;&#xA;        DN:FieldType = 104 ;&#xA;        DN:MemoryOrder = &quot;Z  &quot; ;&#xA;        DN:description = &quot;d(eta) values between half (mass) levels&quot; ;&#xA;        DN:units = &quot;&quot; ;&#xA;        DN:stagger = &quot;&quot; ;&#xA;    float CFN(Time) ;&#xA;        CFN:FieldType = 104 ;&#xA;        CFN:MemoryOrder = &quot;0  &quot; ;&#xA;        CFN:description = &quot;extrapolation constant&quot; ;&#xA;        CFN:units = &quot;&quot; ;&#xA;        CFN:stagger = &quot;&quot; ;&#xA;    float CFN1(Time) ;&#xA;        CFN1:FieldType = 104 ;&#xA;        CFN1:MemoryOrder = &quot;0  &quot; ;&#xA;        CFN1:description = &quot;extrapolation constant&quot; ;&#xA;        CFN1:units = &quot;&quot; ;&#xA;        CFN1:stagger = &quot;&quot; ;&#xA;    int THIS_IS_AN_IDEAL_RUN(Time) ;&#xA;        THIS_IS_AN_IDEAL_RUN:FieldType = 106 ;&#xA;        THIS_IS_AN_IDEAL_RUN:MemoryOrder = &quot;0  &quot; ;&#xA;        THIS_IS_AN_IDEAL_RUN:description = &quot;T/F flag: this is an ARW ideal simulation&quot; ;&#xA;        THIS_IS_AN_IDEAL_RUN:units = &quot;-&quot; ;&#xA;        THIS_IS_AN_IDEAL_RUN:stagger = &quot;&quot; ;&#xA;    float P_HYD(Time, bottom_top, south_north, west_east) ;&#xA;        P_HYD:FieldType = 104 ;&#xA;        P_HYD:MemoryOrder = &quot;XYZ&quot; ;&#xA;        P_HYD:description = &quot;hydrostatic pressure&quot; ;&#xA;        P_HYD:units = &quot;Pa&quot; ;&#xA;        P_HYD:stagger = &quot;&quot; ;&#xA;        P_HYD:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float Q2(Time, south_north, west_east) ;&#xA;        Q2:FieldType = 104 ;&#xA;        Q2:MemoryOrder = &quot;XY &quot; ;&#xA;        Q2:description = &quot;QV at 2 M&quot; ;&#xA;        Q2:units = &quot;kg kg-1&quot; ;&#xA;        Q2:stagger = &quot;&quot; ;&#xA;        Q2:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float T2(Time, south_north, west_east) ;&#xA;        T2:FieldType = 104 ;&#xA;        T2:MemoryOrder = &quot;XY &quot; ;&#xA;        T2:description = &quot;TEMP at 2 M&quot; ;&#xA;        T2:units = &quot;K&quot; ;&#xA;        T2:stagger = &quot;&quot; ;&#xA;        T2:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float TH2(Time, south_north, west_east) ;&#xA;        TH2:FieldType = 104 ;&#xA;        TH2:MemoryOrder = &quot;XY &quot; ;&#xA;        TH2:description = &quot;POT TEMP at 2 M&quot; ;&#xA;        TH2:units = &quot;K&quot; ;&#xA;        TH2:stagger = &quot;&quot; ;&#xA;        TH2:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float PSFC(Time, south_north, west_east) ;&#xA;        PSFC:FieldType = 104 ;&#xA;        PSFC:MemoryOrder = &quot;XY &quot; ;&#xA;        PSFC:description = &quot;SFC PRESSURE&quot; ;&#xA;        PSFC:units = &quot;Pa&quot; ;&#xA;        PSFC:stagger = &quot;&quot; ;&#xA;        PSFC:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float U10(Time, south_north, west_east) ;&#xA;        U10:FieldType = 104 ;&#xA;        U10:MemoryOrder = &quot;XY &quot; ;&#xA;        U10:description = &quot;U at 10 M&quot; ;&#xA;        U10:units = &quot;m s-1&quot; ;&#xA;        U10:stagger = &quot;&quot; ;&#xA;        U10:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float V10(Time, south_north, west_east) ;&#xA;        V10:FieldType = 104 ;&#xA;        V10:MemoryOrder = &quot;XY &quot; ;&#xA;        V10:description = &quot;V at 10 M&quot; ;&#xA;        V10:units = &quot;m s-1&quot; ;&#xA;        V10:stagger = &quot;&quot; ;&#xA;        V10:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float RDX(Time) ;&#xA;        RDX:FieldType = 104 ;&#xA;        RDX:MemoryOrder = &quot;0  &quot; ;&#xA;        RDX:description = &quot;INVERSE X GRID LENGTH&quot; ;&#xA;        RDX:units = &quot;&quot; ;&#xA;        RDX:stagger = &quot;&quot; ;&#xA;    float RDY(Time) ;&#xA;        RDY:FieldType = 104 ;&#xA;        RDY:MemoryOrder = &quot;0  &quot; ;&#xA;        RDY:description = &quot;INVERSE Y GRID LENGTH&quot; ;&#xA;        RDY:units = &quot;&quot; ;&#xA;        RDY:stagger = &quot;&quot; ;&#xA;    float RESM(Time) ;&#xA;        RESM:FieldType = 104 ;&#xA;        RESM:MemoryOrder = &quot;0  &quot; ;&#xA;        RESM:description = &quot;TIME WEIGHT CONSTANT FOR SMALL STEPS&quot; ;&#xA;        RESM:units = &quot;&quot; ;&#xA;        RESM:stagger = &quot;&quot; ;&#xA;    float ZETATOP(Time) ;&#xA;        ZETATOP:FieldType = 104 ;&#xA;        ZETATOP:MemoryOrder = &quot;0  &quot; ;&#xA;        ZETATOP:description = &quot;ZETA AT MODEL TOP&quot; ;&#xA;        ZETATOP:units = &quot;&quot; ;&#xA;        ZETATOP:stagger = &quot;&quot; ;&#xA;    float CF1(Time) ;&#xA;        CF1:FieldType = 104 ;&#xA;        CF1:MemoryOrder = &quot;0  &quot; ;&#xA;        CF1:description = &quot;2nd order extrapolation constant&quot; ;&#xA;        CF1:units = &quot;&quot; ;&#xA;        CF1:stagger = &quot;&quot; ;&#xA;    float CF2(Time) ;&#xA;        CF2:FieldType = 104 ;&#xA;        CF2:MemoryOrder = &quot;0  &quot; ;&#xA;        CF2:description = &quot;2nd order extrapolation constant&quot; ;&#xA;        CF2:units = &quot;&quot; ;&#xA;        CF2:stagger = &quot;&quot; ;&#xA;    float CF3(Time) ;&#xA;        CF3:FieldType = 104 ;&#xA;        CF3:MemoryOrder = &quot;0  &quot; ;&#xA;        CF3:description = &quot;2nd order extrapolation constant&quot; ;&#xA;        CF3:units = &quot;&quot; ;&#xA;        CF3:stagger = &quot;&quot; ;&#xA;    int ITIMESTEP(Time) ;&#xA;        ITIMESTEP:FieldType = 106 ;&#xA;        ITIMESTEP:MemoryOrder = &quot;0  &quot; ;&#xA;        ITIMESTEP:description = &quot;&quot; ;&#xA;        ITIMESTEP:units = &quot;&quot; ;&#xA;        ITIMESTEP:stagger = &quot;&quot; ;&#xA;    float XTIME(Time) ;&#xA;        XTIME:FieldType = 104 ;&#xA;        XTIME:MemoryOrder = &quot;0  &quot; ;&#xA;        XTIME:description = &quot;minutes since 2017-06-17 00:00:00&quot; ;&#xA;        XTIME:units = &quot;minutes since 2017-06-17 00:00:00&quot; ;&#xA;        XTIME:stagger = &quot;&quot; ;&#xA;    float QVAPOR(Time, bottom_top, south_north, west_east) ;&#xA;        QVAPOR:FieldType = 104 ;&#xA;        QVAPOR:MemoryOrder = &quot;XYZ&quot; ;&#xA;        QVAPOR:description = &quot;Water vapor mixing ratio&quot; ;&#xA;        QVAPOR:units = &quot;kg kg-1&quot; ;&#xA;        QVAPOR:stagger = &quot;&quot; ;&#xA;        QVAPOR:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float QCLOUD(Time, bottom_top, south_north, west_east) ;&#xA;        QCLOUD:FieldType = 104 ;&#xA;        QCLOUD:MemoryOrder = &quot;XYZ&quot; ;&#xA;        QCLOUD:description = &quot;Cloud water mixing ratio&quot; ;&#xA;        QCLOUD:units = &quot;kg kg-1&quot; ;&#xA;        QCLOUD:stagger = &quot;&quot; ;&#xA;        QCLOUD:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float QRAIN(Time, bottom_top, south_north, west_east) ;&#xA;        QRAIN:FieldType = 104 ;&#xA;        QRAIN:MemoryOrder = &quot;XYZ&quot; ;&#xA;        QRAIN:description = &quot;Rain water mixing ratio&quot; ;&#xA;        QRAIN:units = &quot;kg kg-1&quot; ;&#xA;        QRAIN:stagger = &quot;&quot; ;&#xA;        QRAIN:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float QICE(Time, bottom_top, south_north, west_east) ;&#xA;        QICE:FieldType = 104 ;&#xA;        QICE:MemoryOrder = &quot;XYZ&quot; ;&#xA;        QICE:description = &quot;Ice mixing ratio&quot; ;&#xA;        QICE:units = &quot;kg kg-1&quot; ;&#xA;        QICE:stagger = &quot;&quot; ;&#xA;        QICE:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float QSNOW(Time, bottom_top, south_north, west_east) ;&#xA;        QSNOW:FieldType = 104 ;&#xA;        QSNOW:MemoryOrder = &quot;XYZ&quot; ;&#xA;        QSNOW:description = &quot;Snow mixing ratio&quot; ;&#xA;        QSNOW:units = &quot;kg kg-1&quot; ;&#xA;        QSNOW:stagger = &quot;&quot; ;&#xA;        QSNOW:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float QGRAUP(Time, bottom_top, south_north, west_east) ;&#xA;        QGRAUP:FieldType = 104 ;&#xA;        QGRAUP:MemoryOrder = &quot;XYZ&quot; ;&#xA;        QGRAUP:description = &quot;Graupel mixing ratio&quot; ;&#xA;        QGRAUP:units = &quot;kg kg-1&quot; ;&#xA;        QGRAUP:stagger = &quot;&quot; ;&#xA;        QGRAUP:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float QNICE(Time, bottom_top, south_north, west_east) ;&#xA;        QNICE:FieldType = 104 ;&#xA;        QNICE:MemoryOrder = &quot;XYZ&quot; ;&#xA;        QNICE:description = &quot;Ice Number concentration&quot; ;&#xA;        QNICE:units = &quot;  kg-1&quot; ;&#xA;        QNICE:stagger = &quot;&quot; ;&#xA;        QNICE:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float QNRAIN(Time, bottom_top, south_north, west_east) ;&#xA;        QNRAIN:FieldType = 104 ;&#xA;        QNRAIN:MemoryOrder = &quot;XYZ&quot; ;&#xA;        QNRAIN:description = &quot;Rain Number concentration&quot; ;&#xA;        QNRAIN:units = &quot;  kg(-1)&quot; ;&#xA;        QNRAIN:stagger = &quot;&quot; ;&#xA;        QNRAIN:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float SHDMAX(Time, south_north, west_east) ;&#xA;        SHDMAX:FieldType = 104 ;&#xA;        SHDMAX:MemoryOrder = &quot;XY &quot; ;&#xA;        SHDMAX:description = &quot;ANNUAL MAX VEG FRACTION&quot; ;&#xA;        SHDMAX:units = &quot;&quot; ;&#xA;        SHDMAX:stagger = &quot;&quot; ;&#xA;        SHDMAX:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float SHDMIN(Time, south_north, west_east) ;&#xA;        SHDMIN:FieldType = 104 ;&#xA;        SHDMIN:MemoryOrder = &quot;XY &quot; ;&#xA;        SHDMIN:description = &quot;ANNUAL MIN VEG FRACTION&quot; ;&#xA;        SHDMIN:units = &quot;&quot; ;&#xA;        SHDMIN:stagger = &quot;&quot; ;&#xA;        SHDMIN:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float SNOALB(Time, south_north, west_east) ;&#xA;        SNOALB:FieldType = 104 ;&#xA;        SNOALB:MemoryOrder = &quot;XY &quot; ;&#xA;        SNOALB:description = &quot;ANNUAL MAX SNOW ALBEDO IN FRACTION&quot; ;&#xA;        SNOALB:units = &quot;&quot; ;&#xA;        SNOALB:stagger = &quot;&quot; ;&#xA;        SNOALB:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float TSLB(Time, soil_layers_stag, south_north, west_east) ;&#xA;        TSLB:FieldType = 104 ;&#xA;        TSLB:MemoryOrder = &quot;XYZ&quot; ;&#xA;        TSLB:description = &quot;SOIL TEMPERATURE&quot; ;&#xA;        TSLB:units = &quot;K&quot; ;&#xA;        TSLB:stagger = &quot;Z&quot; ;&#xA;        TSLB:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float SMOIS(Time, soil_layers_stag, south_north, west_east) ;&#xA;        SMOIS:FieldType = 104 ;&#xA;        SMOIS:MemoryOrder = &quot;XYZ&quot; ;&#xA;        SMOIS:description = &quot;SOIL MOISTURE&quot; ;&#xA;        SMOIS:units = &quot;m3 m-3&quot; ;&#xA;        SMOIS:stagger = &quot;Z&quot; ;&#xA;        SMOIS:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float SH2O(Time, soil_layers_stag, south_north, west_east) ;&#xA;        SH2O:FieldType = 104 ;&#xA;        SH2O:MemoryOrder = &quot;XYZ&quot; ;&#xA;        SH2O:description = &quot;SOIL LIQUID WATER&quot; ;&#xA;        SH2O:units = &quot;m3 m-3&quot; ;&#xA;        SH2O:stagger = &quot;Z&quot; ;&#xA;        SH2O:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float SMCREL(Time, soil_layers_stag, south_north, west_east) ;&#xA;        SMCREL:FieldType = 104 ;&#xA;        SMCREL:MemoryOrder = &quot;XYZ&quot; ;&#xA;        SMCREL:description = &quot;RELATIVE SOIL MOISTURE&quot; ;&#xA;        SMCREL:units = &quot;&quot; ;&#xA;        SMCREL:stagger = &quot;Z&quot; ;&#xA;        SMCREL:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float SEAICE(Time, south_north, west_east) ;&#xA;        SEAICE:FieldType = 104 ;&#xA;        SEAICE:MemoryOrder = &quot;XY &quot; ;&#xA;        SEAICE:description = &quot;SEA ICE FLAG&quot; ;&#xA;        SEAICE:units = &quot;&quot; ;&#xA;        SEAICE:stagger = &quot;&quot; ;&#xA;        SEAICE:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float XICEM(Time, south_north, west_east) ;&#xA;        XICEM:FieldType = 104 ;&#xA;        XICEM:MemoryOrder = &quot;XY &quot; ;&#xA;        XICEM:description = &quot;SEA ICE FLAG (PREVIOUS STEP)&quot; ;&#xA;        XICEM:units = &quot;&quot; ;&#xA;        XICEM:stagger = &quot;&quot; ;&#xA;        XICEM:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float SFROFF(Time, south_north, west_east) ;&#xA;        SFROFF:FieldType = 104 ;&#xA;        SFROFF:MemoryOrder = &quot;XY &quot; ;&#xA;        SFROFF:description = &quot;SURFACE RUNOFF&quot; ;&#xA;        SFROFF:units = &quot;mm&quot; ;&#xA;        SFROFF:stagger = &quot;&quot; ;&#xA;        SFROFF:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float UDROFF(Time, south_north, west_east) ;&#xA;        UDROFF:FieldType = 104 ;&#xA;        UDROFF:MemoryOrder = &quot;XY &quot; ;&#xA;        UDROFF:description = &quot;UNDERGROUND RUNOFF&quot; ;&#xA;        UDROFF:units = &quot;mm&quot; ;&#xA;        UDROFF:stagger = &quot;&quot; ;&#xA;        UDROFF:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    int IVGTYP(Time, south_north, west_east) ;&#xA;        IVGTYP:FieldType = 106 ;&#xA;        IVGTYP:MemoryOrder = &quot;XY &quot; ;&#xA;        IVGTYP:description = &quot;DOMINANT VEGETATION CATEGORY&quot; ;&#xA;        IVGTYP:units = &quot;&quot; ;&#xA;        IVGTYP:stagger = &quot;&quot; ;&#xA;        IVGTYP:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    int ISLTYP(Time, south_north, west_east) ;&#xA;        ISLTYP:FieldType = 106 ;&#xA;        ISLTYP:MemoryOrder = &quot;XY &quot; ;&#xA;        ISLTYP:description = &quot;DOMINANT SOIL CATEGORY&quot; ;&#xA;        ISLTYP:units = &quot;&quot; ;&#xA;        ISLTYP:stagger = &quot;&quot; ;&#xA;        ISLTYP:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float VEGFRA(Time, south_north, west_east) ;&#xA;        VEGFRA:FieldType = 104 ;&#xA;        VEGFRA:MemoryOrder = &quot;XY &quot; ;&#xA;        VEGFRA:description = &quot;VEGETATION FRACTION&quot; ;&#xA;        VEGFRA:units = &quot;&quot; ;&#xA;        VEGFRA:stagger = &quot;&quot; ;&#xA;        VEGFRA:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float GRDFLX(Time, south_north, west_east) ;&#xA;        GRDFLX:FieldType = 104 ;&#xA;        GRDFLX:MemoryOrder = &quot;XY &quot; ;&#xA;        GRDFLX:description = &quot;GROUND HEAT FLUX&quot; ;&#xA;        GRDFLX:units = &quot;W m-2&quot; ;&#xA;        GRDFLX:stagger = &quot;&quot; ;&#xA;        GRDFLX:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float ACGRDFLX(Time, south_north, west_east) ;&#xA;        ACGRDFLX:FieldType = 104 ;&#xA;        ACGRDFLX:MemoryOrder = &quot;XY &quot; ;&#xA;        ACGRDFLX:description = &quot;ACCUMULATED GROUND HEAT FLUX&quot; ;&#xA;        ACGRDFLX:units = &quot;J m-2&quot; ;&#xA;        ACGRDFLX:stagger = &quot;&quot; ;&#xA;        ACGRDFLX:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float ACSNOM(Time, south_north, west_east) ;&#xA;        ACSNOM:FieldType = 104 ;&#xA;        ACSNOM:MemoryOrder = &quot;XY &quot; ;&#xA;        ACSNOM:description = &quot;ACCUMULATED MELTED SNOW&quot; ;&#xA;        ACSNOM:units = &quot;kg m-2&quot; ;&#xA;        ACSNOM:stagger = &quot;&quot; ;&#xA;        ACSNOM:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float SNOW(Time, south_north, west_east) ;&#xA;        SNOW:FieldType = 104 ;&#xA;        SNOW:MemoryOrder = &quot;XY &quot; ;&#xA;        SNOW:description = &quot;SNOW WATER EQUIVALENT&quot; ;&#xA;        SNOW:units = &quot;kg m-2&quot; ;&#xA;        SNOW:stagger = &quot;&quot; ;&#xA;        SNOW:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float SNOWH(Time, south_north, west_east) ;&#xA;        SNOWH:FieldType = 104 ;&#xA;        SNOWH:MemoryOrder = &quot;XY &quot; ;&#xA;        SNOWH:description = &quot;PHYSICAL SNOW DEPTH&quot; ;&#xA;        SNOWH:units = &quot;m&quot; ;&#xA;        SNOWH:stagger = &quot;&quot; ;&#xA;        SNOWH:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float CANWAT(Time, south_north, west_east) ;&#xA;        CANWAT:FieldType = 104 ;&#xA;        CANWAT:MemoryOrder = &quot;XY &quot; ;&#xA;        CANWAT:description = &quot;CANOPY WATER&quot; ;&#xA;        CANWAT:units = &quot;kg m-2&quot; ;&#xA;        CANWAT:stagger = &quot;&quot; ;&#xA;        CANWAT:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float SSTSK(Time, south_north, west_east) ;&#xA;        SSTSK:FieldType = 104 ;&#xA;        SSTSK:MemoryOrder = &quot;XY &quot; ;&#xA;        SSTSK:description = &quot;SKIN SEA SURFACE TEMPERATURE&quot; ;&#xA;        SSTSK:units = &quot;K&quot; ;&#xA;        SSTSK:stagger = &quot;&quot; ;&#xA;        SSTSK:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float COSZEN(Time, south_north, west_east) ;&#xA;        COSZEN:FieldType = 104 ;&#xA;        COSZEN:MemoryOrder = &quot;XY &quot; ;&#xA;        COSZEN:description = &quot;COS of SOLAR ZENITH ANGLE&quot; ;&#xA;        COSZEN:units = &quot;dimensionless&quot; ;&#xA;        COSZEN:stagger = &quot;&quot; ;&#xA;        COSZEN:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float LAI(Time, south_north, west_east) ;&#xA;        LAI:FieldType = 104 ;&#xA;        LAI:MemoryOrder = &quot;XY &quot; ;&#xA;        LAI:description = &quot;LEAF AREA INDEX&quot; ;&#xA;        LAI:units = &quot;m-2/m-2&quot; ;&#xA;        LAI:stagger = &quot;&quot; ;&#xA;        LAI:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float VAR(Time, south_north, west_east) ;&#xA;        VAR:FieldType = 104 ;&#xA;        VAR:MemoryOrder = &quot;XY &quot; ;&#xA;        VAR:description = &quot;OROGRAPHIC VARIANCE&quot; ;&#xA;        VAR:units = &quot;&quot; ;&#xA;        VAR:stagger = &quot;&quot; ;&#xA;        VAR:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float MAPFAC_M(Time, south_north, west_east) ;&#xA;        MAPFAC_M:FieldType = 104 ;&#xA;        MAPFAC_M:MemoryOrder = &quot;XY &quot; ;&#xA;        MAPFAC_M:description = &quot;Map scale factor on mass grid&quot; ;&#xA;        MAPFAC_M:units = &quot;&quot; ;&#xA;        MAPFAC_M:stagger = &quot;&quot; ;&#xA;        MAPFAC_M:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float MAPFAC_U(Time, south_north, west_east_stag) ;&#xA;        MAPFAC_U:FieldType = 104 ;&#xA;        MAPFAC_U:MemoryOrder = &quot;XY &quot; ;&#xA;        MAPFAC_U:description = &quot;Map scale factor on u-grid&quot; ;&#xA;        MAPFAC_U:units = &quot;&quot; ;&#xA;        MAPFAC_U:stagger = &quot;X&quot; ;&#xA;        MAPFAC_U:coordinates = &quot;XLONG_U XLAT_U XTIME&quot; ;&#xA;    float MAPFAC_V(Time, south_north_stag, west_east) ;&#xA;        MAPFAC_V:FieldType = 104 ;&#xA;        MAPFAC_V:MemoryOrder = &quot;XY &quot; ;&#xA;        MAPFAC_V:description = &quot;Map scale factor on v-grid&quot; ;&#xA;        MAPFAC_V:units = &quot;&quot; ;&#xA;        MAPFAC_V:stagger = &quot;Y&quot; ;&#xA;        MAPFAC_V:coordinates = &quot;XLONG_V XLAT_V XTIME&quot; ;&#xA;    float MAPFAC_MX(Time, south_north, west_east) ;&#xA;        MAPFAC_MX:FieldType = 104 ;&#xA;        MAPFAC_MX:MemoryOrder = &quot;XY &quot; ;&#xA;        MAPFAC_MX:description = &quot;Map scale factor on mass grid, x direction&quot; ;&#xA;        MAPFAC_MX:units = &quot;&quot; ;&#xA;        MAPFAC_MX:stagger = &quot;&quot; ;&#xA;        MAPFAC_MX:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float MAPFAC_MY(Time, south_north, west_east) ;&#xA;        MAPFAC_MY:FieldType = 104 ;&#xA;        MAPFAC_MY:MemoryOrder = &quot;XY &quot; ;&#xA;        MAPFAC_MY:description = &quot;Map scale factor on mass grid, y direction&quot; ;&#xA;        MAPFAC_MY:units = &quot;&quot; ;&#xA;        MAPFAC_MY:stagger = &quot;&quot; ;&#xA;        MAPFAC_MY:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float MAPFAC_UX(Time, south_north, west_east_stag) ;&#xA;        MAPFAC_UX:FieldType = 104 ;&#xA;        MAPFAC_UX:MemoryOrder = &quot;XY &quot; ;&#xA;        MAPFAC_UX:description = &quot;Map scale factor on u-grid, x direction&quot; ;&#xA;        MAPFAC_UX:units = &quot;&quot; ;&#xA;        MAPFAC_UX:stagger = &quot;X&quot; ;&#xA;        MAPFAC_UX:coordinates = &quot;XLONG_U XLAT_U XTIME&quot; ;&#xA;    float MAPFAC_UY(Time, south_north, west_east_stag) ;&#xA;        MAPFAC_UY:FieldType = 104 ;&#xA;        MAPFAC_UY:MemoryOrder = &quot;XY &quot; ;&#xA;        MAPFAC_UY:description = &quot;Map scale factor on u-grid, y direction&quot; ;&#xA;        MAPFAC_UY:units = &quot;&quot; ;&#xA;        MAPFAC_UY:stagger = &quot;X&quot; ;&#xA;        MAPFAC_UY:coordinates = &quot;XLONG_U XLAT_U XTIME&quot; ;&#xA;    float MAPFAC_VX(Time, south_north_stag, west_east) ;&#xA;        MAPFAC_VX:FieldType = 104 ;&#xA;        MAPFAC_VX:MemoryOrder = &quot;XY &quot; ;&#xA;        MAPFAC_VX:description = &quot;Map scale factor on v-grid, x direction&quot; ;&#xA;        MAPFAC_VX:units = &quot;&quot; ;&#xA;        MAPFAC_VX:stagger = &quot;Y&quot; ;&#xA;        MAPFAC_VX:coordinates = &quot;XLONG_V XLAT_V XTIME&quot; ;&#xA;    float MF_VX_INV(Time, south_north_stag, west_east) ;&#xA;        MF_VX_INV:FieldType = 104 ;&#xA;        MF_VX_INV:MemoryOrder = &quot;XY &quot; ;&#xA;        MF_VX_INV:description = &quot;Inverse map scale factor on v-grid, x direction&quot; ;&#xA;        MF_VX_INV:units = &quot;&quot; ;&#xA;        MF_VX_INV:stagger = &quot;Y&quot; ;&#xA;        MF_VX_INV:coordinates = &quot;XLONG_V XLAT_V XTIME&quot; ;&#xA;    float MAPFAC_VY(Time, south_north_stag, west_east) ;&#xA;        MAPFAC_VY:FieldType = 104 ;&#xA;        MAPFAC_VY:MemoryOrder = &quot;XY &quot; ;&#xA;        MAPFAC_VY:description = &quot;Map scale factor on v-grid, y direction&quot; ;&#xA;        MAPFAC_VY:units = &quot;&quot; ;&#xA;        MAPFAC_VY:stagger = &quot;Y&quot; ;&#xA;        MAPFAC_VY:coordinates = &quot;XLONG_V XLAT_V XTIME&quot; ;&#xA;    float F(Time, south_north, west_east) ;&#xA;        F:FieldType = 104 ;&#xA;        F:MemoryOrder = &quot;XY &quot; ;&#xA;        F:description = &quot;Coriolis sine latitude term&quot; ;&#xA;        F:units = &quot;s-1&quot; ;&#xA;        F:stagger = &quot;&quot; ;&#xA;        F:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float E(Time, south_north, west_east) ;&#xA;        E:FieldType = 104 ;&#xA;        E:MemoryOrder = &quot;XY &quot; ;&#xA;        E:description = &quot;Coriolis cosine latitude term&quot; ;&#xA;        E:units = &quot;s-1&quot; ;&#xA;        E:stagger = &quot;&quot; ;&#xA;        E:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float SINALPHA(Time, south_north, west_east) ;&#xA;        SINALPHA:FieldType = 104 ;&#xA;        SINALPHA:MemoryOrder = &quot;XY &quot; ;&#xA;        SINALPHA:description = &quot;Local sine of map rotation&quot; ;&#xA;        SINALPHA:units = &quot;&quot; ;&#xA;        SINALPHA:stagger = &quot;&quot; ;&#xA;        SINALPHA:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float COSALPHA(Time, south_north, west_east) ;&#xA;        COSALPHA:FieldType = 104 ;&#xA;        COSALPHA:MemoryOrder = &quot;XY &quot; ;&#xA;        COSALPHA:description = &quot;Local cosine of map rotation&quot; ;&#xA;        COSALPHA:units = &quot;&quot; ;&#xA;        COSALPHA:stagger = &quot;&quot; ;&#xA;        COSALPHA:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float HGT(Time, south_north, west_east) ;&#xA;        HGT:FieldType = 104 ;&#xA;        HGT:MemoryOrder = &quot;XY &quot; ;&#xA;        HGT:description = &quot;Terrain Height&quot; ;&#xA;        HGT:units = &quot;m&quot; ;&#xA;        HGT:stagger = &quot;&quot; ;&#xA;        HGT:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float TSK(Time, south_north, west_east) ;&#xA;        TSK:FieldType = 104 ;&#xA;        TSK:MemoryOrder = &quot;XY &quot; ;&#xA;        TSK:description = &quot;SURFACE SKIN TEMPERATURE&quot; ;&#xA;        TSK:units = &quot;K&quot; ;&#xA;        TSK:stagger = &quot;&quot; ;&#xA;        TSK:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float P_TOP(Time) ;&#xA;        P_TOP:FieldType = 104 ;&#xA;        P_TOP:MemoryOrder = &quot;0  &quot; ;&#xA;        P_TOP:description = &quot;PRESSURE TOP OF THE MODEL&quot; ;&#xA;        P_TOP:units = &quot;Pa&quot; ;&#xA;        P_TOP:stagger = &quot;&quot; ;&#xA;    float T00(Time) ;&#xA;        T00:FieldType = 104 ;&#xA;        T00:MemoryOrder = &quot;0  &quot; ;&#xA;        T00:description = &quot;BASE STATE TEMPERATURE&quot; ;&#xA;        T00:units = &quot;K&quot; ;&#xA;        T00:stagger = &quot;&quot; ;&#xA;    float P00(Time) ;&#xA;        P00:FieldType = 104 ;&#xA;        P00:MemoryOrder = &quot;0  &quot; ;&#xA;        P00:description = &quot;BASE STATE PRESURE&quot; ;&#xA;        P00:units = &quot;Pa&quot; ;&#xA;        P00:stagger = &quot;&quot; ;&#xA;    float TLP(Time) ;&#xA;        TLP:FieldType = 104 ;&#xA;        TLP:MemoryOrder = &quot;0  &quot; ;&#xA;        TLP:description = &quot;BASE STATE LAPSE RATE&quot; ;&#xA;        TLP:units = &quot;&quot; ;&#xA;        TLP:stagger = &quot;&quot; ;&#xA;    float TISO(Time) ;&#xA;        TISO:FieldType = 104 ;&#xA;        TISO:MemoryOrder = &quot;0  &quot; ;&#xA;        TISO:description = &quot;TEMP AT WHICH THE BASE T TURNS CONST&quot; ;&#xA;        TISO:units = &quot;K&quot; ;&#xA;        TISO:stagger = &quot;&quot; ;&#xA;    float TLP_STRAT(Time) ;&#xA;        TLP_STRAT:FieldType = 104 ;&#xA;        TLP_STRAT:MemoryOrder = &quot;0  &quot; ;&#xA;        TLP_STRAT:description = &quot;BASE STATE LAPSE RATE (DT/D(LN(P)) IN STRATOSPHERE&quot; ;&#xA;        TLP_STRAT:units = &quot;K&quot; ;&#xA;        TLP_STRAT:stagger = &quot;&quot; ;&#xA;    float P_STRAT(Time) ;&#xA;        P_STRAT:FieldType = 104 ;&#xA;        P_STRAT:MemoryOrder = &quot;0  &quot; ;&#xA;        P_STRAT:description = &quot;BASE STATE PRESSURE AT BOTTOM OF STRATOSPHERE&quot; ;&#xA;        P_STRAT:units = &quot;Pa&quot; ;&#xA;        P_STRAT:stagger = &quot;&quot; ;&#xA;    float MAX_MSTFX(Time) ;&#xA;        MAX_MSTFX:FieldType = 104 ;&#xA;        MAX_MSTFX:MemoryOrder = &quot;0  &quot; ;&#xA;        MAX_MSTFX:description = &quot;Max map factor in domain&quot; ;&#xA;        MAX_MSTFX:units = &quot;&quot; ;&#xA;        MAX_MSTFX:stagger = &quot;&quot; ;&#xA;    float MAX_MSTFY(Time) ;&#xA;        MAX_MSTFY:FieldType = 104 ;&#xA;        MAX_MSTFY:MemoryOrder = &quot;0  &quot; ;&#xA;        MAX_MSTFY:description = &quot;Max map factor in domain&quot; ;&#xA;        MAX_MSTFY:units = &quot;&quot; ;&#xA;        MAX_MSTFY:stagger = &quot;&quot; ;&#xA;    float RAINC(Time, south_north, west_east) ;&#xA;        RAINC:FieldType = 104 ;&#xA;        RAINC:MemoryOrder = &quot;XY &quot; ;&#xA;        RAINC:description = &quot;ACCUMULATED TOTAL CUMULUS PRECIPITATION&quot; ;&#xA;        RAINC:units = &quot;mm&quot; ;&#xA;        RAINC:stagger = &quot;&quot; ;&#xA;        RAINC:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;    float RAINSH(Time, south_north, west_east) ;&#xA;        RAINSH:FieldType = 104 ;&#xA;        RAINSH:MemoryOrder = &quot;XY &quot; ;&#xA;        RAINSH:description = &quot;ACCUMULATED SHALLOW CUMULUS&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="19120" LastEditorUserId="106" LastEditDate="2020-03-20T16:30:24.983" LastActivityDate="2020-03-20T16:30:24.983" Title="Wind rose WRF-PYTHON" Tags="|wind|wrf|python|simulation|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19438" PostTypeId="2" ParentId="19421" CreationDate="2020-03-11T15:40:44.093" Score="1" Body="&lt;p&gt;Michael Walsby's answer is correct, but I thought I'd try putting it another way:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The sun &lt;em&gt;does&lt;/em&gt; illuminate the side of the earth that faces it, not just every day of the year but every moment of the year.[1]&#xA;But, because of the tilt that you have mentioned, the &quot;side&quot; facing the sun does not usually correspond to a hemisphere that starts and ends at the north and south poles.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[1] except during eclipses&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2020-03-11T15:40:44.093" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19439" PostTypeId="1" CreationDate="2020-03-11T16:25:41.203" Score="6" ViewCount="273" Body="&lt;p&gt;I find that when ever I learn of a new fossil, the age of said fossil is always mentioned. This perplexes me given how intuitively rare it seems to have radioactive material to date a formation. I know that Paleontologists also use other fossils in the formation to date a new fossils however surely there have been cases where we have found new fossils that we have no way of knowing the age?&lt;/p&gt;&#xA;" OwnerUserId="19121" LastActivityDate="2022-07-22T15:20:10.153" Title="Has there ever been a case where we have found what appears to be a prehistoric fossil but have no way of dating it?" Tags="|geology|fossils|paleontology|dating|" AnswerCount="4" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19440" PostTypeId="2" ParentId="19439" CreationDate="2020-03-11T19:45:48.727" Score="0" Body="&lt;p&gt;There is always some way of dating a fossil. The problem is not so much in finding a way as in finding an accurate way. Laboratories usually have to deal with incredibly small amounts of material. Take the potassium - argon method for instance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A volcanic tuff will not be pure potassium, it will only contain a trace. Only about one potassium atom in a thousand is the radioactive potassium 40 (half life 1,3000,000,000 years). It is therefore only useful in dating something millions of years old, no good for dating Neanderthal fossils, for example. The difficulties don't end there. Only 11% of K40 decays in a very unusual way to become Ar40, the rest decays by normal beta decay to become calcium 40.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So you can see that the procedures are so delicate and sensitive because of the minute quantities scientists have to work with that it is a wonder they get useful results at all. Such dating is often contentious as not surprisingly, like all radiometric dating, it is subject to error. Similar problems exist with regard to carbon 14, which is suited to more recent fossils like Neanderthal man.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For dating fossils as far back as the late Precambrian a new dating method called the rhenium - osmium method has recently been used, and is much more accurate for that period than previous methods, being capable of reliably dating fossils a billion years old. Previous inaccurate datings were rendered obsolete.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fossils found in limestone cave accretions such as Raymond Dart's Taung child (a gracile australopithecine from S. Africa) are notoriously difficult to date because of the lack of stratigraphy and suitable radioactive elements.&lt;/p&gt;&#xA;" OwnerUserId="17166" LastActivityDate="2020-03-11T19:45:48.727" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19441" PostTypeId="2" ParentId="19421" CreationDate="2020-03-11T20:42:10.027" Score="3" Body="&lt;p&gt;If the diameter of the Sun is &lt;span class=&quot;math-container&quot;&gt;$R_S$&lt;/span&gt;, the diameter of the Earth is &lt;span class=&quot;math-container&quot;&gt;$R_E$&lt;/span&gt;, and the orbital radius of the Earth is &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt;, as in the drawing below (sorry about the quality),  then you can do some geometry and compute &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt;, which is the angle at which the light from the edge of the Sun's disk as seen from Earth is tangent to the Earth's surface referenced to a line between the centres of the Sun and the Earth.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cKo48.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cKo48.jpg&quot; alt=&quot;Sun, Earth&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The expression for &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; comes out to be&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\theta = \sin^{-1}\left(\frac{R_S - R_E}{r}\right)$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(You get this by extending the tangent line and the line connecting the centres, realising that this makes two similar right triangles with the angle at the tip being &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt;, and the base of the larger one being &lt;span class=&quot;math-container&quot;&gt;$R_S$&lt;/span&gt;, then working out what the hypotenuse of the larger triangle is, which gives you &lt;span class=&quot;math-container&quot;&gt;$\sin\theta$&lt;/span&gt;.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; is small we can just say &lt;span class=&quot;math-container&quot;&gt;$\sin \theta = \theta$&lt;/span&gt; in the usual way, and plugging in values we get &lt;span class=&quot;math-container&quot;&gt;$\theta \approx 0.0046\,\mathrm{rad}$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the angle at which the Earth's rotation axis is tilted is more than &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt;, then there will be a period of the year during which the poles are not illuminated as the point at which the Sun's light is tangent to the Earth's surface is sunward of the pole.  Well, the angle of tilt is &lt;span class=&quot;math-container&quot;&gt;$23.5^\circ \approx 0.41\,\mathrm{rad}$&lt;/span&gt;, which is about &lt;span class=&quot;math-container&quot;&gt;$90\theta$&lt;/span&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user18801" LastEditorDisplayName="user18801" LastEditDate="2020-03-12T09:47:04.340" LastActivityDate="2020-03-12T09:47:04.340" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19442" PostTypeId="1" AcceptedAnswerId="19455" CreationDate="2020-03-12T06:54:52.910" Score="4" ViewCount="187" Body="&lt;p&gt;Some days I can smell bad smelling exhaust 50 meters or more away from the bus stop. I think the air is usually moist those days. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does exhaust gases linger longer if the air is moist near the ground? Is it smog I am smelling those days?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On morning 12 march it was about&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Temperature: 4°C&lt;/li&gt;&#xA;&lt;li&gt;Humidity:93%&lt;/li&gt;&#xA;&lt;li&gt;Barometer:978 mbar&lt;/li&gt;&#xA;&lt;li&gt;Wind:10 m/s&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Looking at the data from earth.nullschool.net at a few hours before that morning I saw surface temperature of 5.1°C and 5.8°C at 1000hPa.&lt;/p&gt;&#xA;" OwnerUserId="19124" LastEditorUserId="19124" LastEditDate="2020-03-14T08:41:03.510" LastActivityDate="2020-03-14T08:41:03.510" Title="Why does exhaust smells linger some days?" Tags="|meteorology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19443" PostTypeId="2" ParentId="19426" CreationDate="2020-03-12T12:36:05.340" Score="1" Body="&lt;p&gt;According to page 43 of the &lt;a href=&quot;https://earth.esa.int/documents/10174/679851/LANDSAT_Products_Description_Document.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Landsat Products Description Document&lt;/a&gt; the acquisition time is GMT when there is a &quot;Z&quot; behind the time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SXhP8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SXhP8.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14194" LastActivityDate="2020-03-12T12:36:05.340" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19444" PostTypeId="1" CreationDate="2020-03-12T14:39:24.683" Score="7" ViewCount="2805" Body="&lt;p&gt;I want to calculate the total &lt;span class=&quot;math-container&quot;&gt;$\rm{NO_2}$&lt;/span&gt; amount in a year using satellite &lt;a href=&quot;https://developers.google.com/earth-engine/datasets/catalog/COPERNICUS_S5P_OFFL_L3_NO2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sentinel-5p NO2 dataset&lt;/a&gt;. But the problem is sentinel satellite data stored in &lt;span class=&quot;math-container&quot;&gt;$\rm\frac{mol}{m^2}$&lt;/span&gt; unit. But I have to compare it to &lt;code&gt;lb&lt;/code&gt; or &lt;code&gt;ton&lt;/code&gt; or any other unit to compare &lt;span class=&quot;math-container&quot;&gt;$\rm{NO_2}$&lt;/span&gt; amount with ground-level &lt;span class=&quot;math-container&quot;&gt;$\rm{NO_2}$&lt;/span&gt; measurement. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;Example:&lt;/strong&gt; In our satellite dataset, we have &lt;strong&gt;tropospheric &lt;span class=&quot;math-container&quot;&gt;$\rm{NO_2}$&lt;/span&gt; column number density&lt;/strong&gt; which unit is &lt;span class=&quot;math-container&quot;&gt;$\rm\frac{mol}{m^2}$&lt;/span&gt;. We want to calculate&#xA;  the total yearly &lt;span class=&quot;math-container&quot;&gt;$\rm{NO_2}$&lt;/span&gt; of California. So we have summed all the year&#xA;  data of California. Then we get a total yearly &lt;span class=&quot;math-container&quot;&gt;$\rm{NO_2}$&lt;/span&gt; 4200 &lt;span class=&quot;math-container&quot;&gt;$\rm\frac{mol}{m^2}$&lt;/span&gt;. I&#xA;  want to convert this to &lt;code&gt;gram&lt;/code&gt; or &lt;code&gt;ton&lt;/code&gt; or &lt;code&gt;lb&lt;/code&gt;. For example, the&#xA;  total yearly &lt;span class=&quot;math-container&quot;&gt;$\rm{NO_2}$&lt;/span&gt; of California is 35000 ton.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Also, if I convert that &lt;span class=&quot;math-container&quot;&gt;$\rm\frac{mol}{m^2}$&lt;/span&gt; to &lt;span class=&quot;math-container&quot;&gt;$\rm\frac{molec}{cm^2}$&lt;/span&gt;, is it then possible to convert it to total &lt;code&gt;gram&lt;/code&gt; or &lt;code&gt;ton&lt;/code&gt;? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Research&lt;/strong&gt;: I have asked that question in &lt;a href=&quot;https://gis.stackexchange.com/questions/353368/correlating-mol-m2-with-ton-and-lb&quot;&gt;here&lt;/a&gt;. After getting answers, I thought I have found the solutions. But after some more research, it turns out not easy. Because in satellite data what we get is tropospheric vertical column number density and convert them to total mass like total &lt;span class=&quot;math-container&quot;&gt;$\rm{NO_2}$&lt;/span&gt; in gram or ton is not straightforward. These forum posts (&lt;a href=&quot;https://earthscience.stackexchange.com/questions/8860/convert-omi-no2-vertical-column-density-molecules-cm2-into-mixing-ratio-ppm&quot;&gt;#1&lt;/a&gt;, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/19391/convert-no2-concentration-in-sentinel-5p-data-from-mol-m2-to-%CE%BCg-m3-on-the-ground&quot;&gt;#2&lt;/a&gt;, &lt;a href=&quot;https://www.researchgate.net/post/How_can_I_convert_the_unit_from_molecules_cm2_to_ppm&quot; rel=&quot;nofollow noreferrer&quot;&gt;#3&lt;/a&gt;) also somewhat similar to mine, but I didn't get quite a solution to my problem. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT&lt;/strong&gt;: I know that we can easily multiply by area in &lt;span class=&quot;math-container&quot;&gt;$\rm m^2$&lt;/span&gt; to cancel out &lt;span class=&quot;math-container&quot;&gt;$\rm m^2$&lt;/span&gt; in the unit and multiple by &lt;span class=&quot;math-container&quot;&gt;$\rm{NO_2}$&lt;/span&gt; molar mass, but this is not a ground-based problem. We are talking about satellite imagery dataset especially &lt;strong&gt;tropospheric vertical column density&lt;/strong&gt;. &lt;a href=&quot;https://earthscience.stackexchange.com/questions/8860/convert-omi-no2-vertical-column-density-molecules-cm2-into-mixing-ratio-ppm&quot;&gt;#1&lt;/a&gt;, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/19391/convert-no2-concentration-in-sentinel-5p-data-from-mol-m2-to-%CE%BCg-m3-on-the-ground&quot;&gt;#2&lt;/a&gt;, &lt;a href=&quot;https://www.researchgate.net/post/How_can_I_convert_the_unit_from_molecules_cm2_to_ppm&quot; rel=&quot;nofollow noreferrer&quot;&gt;#3&lt;/a&gt; These posts shows why it is different for converting satellite imagery units to ground-based units. &lt;/p&gt;&#xA;" OwnerUserId="19125" LastEditorUserId="6016" LastEditDate="2020-03-12T18:17:38.617" LastActivityDate="2020-03-12T18:17:38.617" Title="How to convert mol/m^2 to total mass ( e.g gram, kg etc )?" Tags="|geophysics|geochemistry|remote-sensing|atmospheric-chemistry|satellites|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19445" PostTypeId="2" ParentId="19439" CreationDate="2020-03-12T15:00:14.587" Score="9" Body="&lt;p&gt;The short answer is no, because we always have some constraint of how old something is.  Sometimes we have fossils with large date error bars, and often we do not know for how long that species existed. A large date range constraint in some cases, like archeology, might not be useful. If the specimen is taken without noting the location it was taken from, then we have no context to date it, which is a big reason not to plunder paleontological sites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For dating a fossil, the context of the rock layer, other fossils, cross-cutting units, and location is key.  Geologists must use a combination of absolute and relative age dating techniques.  Geologists examine the rock layer from which the fossil was found and compare that to other rock layers that stratigraphically correlate to it.  They use basic relative dating approaches, including:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Principle of Superposition: older layers on bottom, younger layers on top&lt;/li&gt;&#xA;&lt;li&gt;Principle of Cross Cutting Relationships: if a feature (like igneous intrusions and faults) cuts through a layer, then that feature is younger than the layer&lt;/li&gt;&#xA;&lt;li&gt;Principle of Original Horizontality: Layers are deposited in a horizontal fashion&lt;/li&gt;&#xA;&lt;li&gt;Principle of Lateral Continuity: Layers are general deposited in a laterally continuous manner until they pinch out; if you see a canyon and similar layer on either side, you can assume it was previously continuous and the canyon is younger.&lt;/li&gt;&#xA;&lt;li&gt;Principle of Faunal Succession: The presence or absence groups of fossils can be used to hone in on the time period&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;There are a wide variety of absolute dating techniques, each with its own time and medium constraints. Radiometric dating, fission track dating, and paleomagnetic approaches are typically restricted to igneous rocks. For radiometric dating, only a small quantity of isotopes are needed for a measurable date. Igneous rocks contain usable quantities of minerals like zircon that are good at holding atoms of uranium and other elements useful in for the absolute age-dating technique. Geologists use absolute dates of rocks that can be dated in combination with relative dating techniques to constrain the age of a rock layer that cannot be dated with absolute techniques.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Fossil morphology must also be considered to determine if you are really looking at a new species or just a special case of a previously identified species. Sometimes, evolutionary approaches can be applied to help place the specimen into a timeline.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Figuring out the temporal extent of a species takes more time and multiple discoveries of samples of that species to better constrain that extent.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A combination of approaches and techniques can help paleontologists be detectives in determining the age of specimen. Like other sciences, geology is social in the sense that it relies on the culmination of the work of many, with multiple lines of complementary pieces of information, to come to a conclusive age. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here are some great articles related to your question:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;DiMaggio, E. and Tripathy-Lang, A., 2019, How Do Scientists Date Fossils?: Smithsonian Magazine, online: &lt;a href=&quot;https://www.smithsonianmag.com/smithsonian-institution/how-do-scientists-date-fossils-180972391/&quot; rel=&quot;noreferrer&quot;&gt;https://www.smithsonianmag.com/smithsonian-institution/how-do-scientists-date-fossils-180972391/&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Peppe, D. J. and Deino, A. L., 2013, Dating Rocks and Fossils Using Geologic Methods: Nature Education Knowledge vol. 4, no. 10:1, online: &lt;a href=&quot;https://www.nature.com/scitable/knowledge/library/dating-rocks-and-fossils-using-geologic-methods-107924044/&quot; rel=&quot;noreferrer&quot;&gt;https://www.nature.com/scitable/knowledge/library/dating-rocks-and-fossils-using-geologic-methods-107924044/&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Here is an example of an &quot;undatable&quot; fossil, where the age could &quot;only&quot; be constrained by 2 million years:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Yong, E., 2015, Why Don't We Know the Age of the New Ancient Human?: The Atlantic, online: &lt;a href=&quot;https://www.theatlantic.com/science/archive/2015/09/why-dont-we-know-the-age-of-the-new-human-ancestor-homo-naledi/405148/&quot; rel=&quot;noreferrer&quot;&gt;https://www.theatlantic.com/science/archive/2015/09/why-dont-we-know-the-age-of-the-new-human-ancestor-homo-naledi/405148/&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="510" LastEditorUserId="510" LastEditDate="2020-03-12T16:46:44.383" LastActivityDate="2020-03-12T16:46:44.383" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19446" PostTypeId="2" ParentId="19408" CreationDate="2020-03-12T15:27:45.533" Score="1" Body="&lt;p&gt;If you are flexible with your choice in software, I would strongly recommend using Bob Herrmann's Computer Programs in Seismology for this work. &lt;a href=&quot;http://www.eas.slu.edu/eqc/eqccps.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.eas.slu.edu/eqc/eqccps.html&lt;/a&gt;. This software package has nice workflows for doing ambient noise tomography and will save you a lot of time over python. For example, you can relatively quickly do group/phase velocity dispersion curve picks. It is also fairly easy to QC your data. Look at the documentation for 'Surface Wave Dispersion - Receiver Function Inversion' on &lt;a href=&quot;http://www.eas.slu.edu/eqc/eqc_cps/CPS/CPS330.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.eas.slu.edu/eqc/eqc_cps/CPS/CPS330.html&lt;/a&gt; for more details.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you must use python, I would suggest writing your own Time-Frequency code as obspy's implementation is not very thoroughly documented, and you still need to get from Obspy's representation to dispersion curves. This will take some time, especially if you want a nice GUI for picking. This is why I recommenced the aforementioned software.&lt;/p&gt;&#xA;" OwnerUserId="18386" LastActivityDate="2020-03-12T15:27:45.533" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19447" PostTypeId="2" ParentId="19444" CreationDate="2020-03-12T15:33:36.977" Score="7" Body="&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\rm \frac{mol}{m^2}$&lt;/span&gt; shows the amount of &lt;span class=&quot;math-container&quot;&gt;$\rm{NO_2}$&lt;/span&gt; in the atmosphere over a square meter of surface area - in mols.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The molar mass of the &lt;span class=&quot;math-container&quot;&gt;$\rm{NO_2}$&lt;/span&gt; is &lt;span class=&quot;math-container&quot;&gt;$14+2\cdot 16=46$&lt;/span&gt;. It means, the mass of 1 mol of &lt;span class=&quot;math-container&quot;&gt;$\rm{NO_2}$&lt;/span&gt; is &lt;span class=&quot;math-container&quot;&gt;$\rm{46g}$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The surface area of the Earth is 510million &lt;span class=&quot;math-container&quot;&gt;$\rm{km^2}$&lt;/span&gt;. Thus, 1 &lt;span class=&quot;math-container&quot;&gt;$\rm \frac{mol}{m^2} \rm{NO_2}$&lt;/span&gt; translates to &lt;span class=&quot;math-container&quot;&gt;$\rm{46 \frac{g}{m^2} \cdot 5.1 \cdot 10^8 km^2}$&lt;/span&gt;, what means a total mass of &lt;span class=&quot;math-container&quot;&gt;$23.46\cdot 10^9 \rm t$&lt;/span&gt; in the whole atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here we assumed a constant distribution of the &lt;span class=&quot;math-container&quot;&gt;$\rm {NO_2}$&lt;/span&gt; in the atmosphere, which is typically not the case in earth science-related problems. Also your research question is about the visualization of a highly non-level distribution. Here you need to integrate (or, considering your digital evironment, sum).&lt;/p&gt;&#xA;" OwnerUserId="6016" LastActivityDate="2020-03-12T15:33:36.977" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19448" PostTypeId="2" ParentId="18796" CreationDate="2020-03-12T16:25:20.183" Score="1" Body="&lt;p&gt;It depends on what purpose you need the data for. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This site &lt;a href=&quot;https://wiki.seg.org/wiki/Open_data&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://wiki.seg.org/wiki/Open_data&lt;/a&gt; gives several sources of data. If it must be land acquisition (as opposed to marine) data then the Poland 2D, Teapot dome 3D, or Stratton 3D surveys might be of interest. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;These free data sets are for pedagogical/research purposes, so if you'd like to 'strike-it-rich' these are not the droids you're looking for.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this helps, &#xA;-D&lt;/p&gt;&#xA;" OwnerUserId="18386" LastActivityDate="2020-03-12T16:25:20.183" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19450" PostTypeId="1" CreationDate="2020-03-12T18:41:49.690" Score="3" ViewCount="665" Body="&lt;p&gt;I understand that the slow and fast carbon cycles are involved in the transport and storing of carbon, but how much of an influence do each of these cycles have on climate change, and how?&lt;/p&gt;&#xA;" OwnerUserId="19127" LastActivityDate="2020-04-08T22:13:28.467" Title="How do the slow and fast carbon cycles influence climate change?" Tags="|climate-change|carbon-cycle|" AnswerCount="2" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19451" PostTypeId="2" ParentId="19450" CreationDate="2020-03-13T03:55:36.233" Score="2" Body="&lt;p&gt;One example of the slow carbon cycle: &lt;a href=&quot;https://pubs.geoscienceworld.org/geology/article-lookup/36/12/1003&quot; rel=&quot;nofollow noreferrer&quot;&gt;Surface uplift of Tibet and Cenozoic global cooling&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Continental weathering on a global scale influences ocean chemistry and imposes a net drawdown of atmospheric CO2 that modulates global climate ... . This observation, in addition to seawater Sr records that suggest an increase in continental weathering after ca. 40 Ma, led researchers to suggest that the uplift and erosion of the Himalayan-Tibetan orogen over the past 40 m.y. has drawn down atmospheric CO2 and cooled the globe, leading to the glacial climate that persists today &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2020-03-13T03:55:36.233" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19452" PostTypeId="1" CreationDate="2020-03-13T08:21:12.687" Score="1" ViewCount="379" Body="&lt;p&gt;I have a netCDF data file as my emmission data in netCDF format. I have interpolated it in my &lt;code&gt;wrfinput_d01&lt;/code&gt; resolution by using CDO. I can write my data to a netCDF file but, I would like to write it in netCDF file like &lt;code&gt;wrfinput_d01&lt;/code&gt;, and change the attributed file to my &lt;code&gt;wrfinput_d01&lt;/code&gt; (&lt;code&gt;time, datestrlen, zdim, ...&lt;/code&gt;), (of curse, I shold say that I have my data in &lt;strong&gt;first layer of wrf-model ,beacuse they are emissions and wouldn't like to be in 64 level.)...&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;How can I write netCDF file from my data, like &quot;wrfinput_d01 &quot; in R or matlab or python?&lt;/li&gt;&#xA;&lt;li&gt;Does any one know?&lt;/li&gt;&#xA;&lt;li&gt;I have my emission data in the &lt;code&gt;wrfinput&lt;/code&gt; resolution, but the netCDF file doesn't look like &lt;code&gt;wrfinput_d01&lt;/code&gt;? :(&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Thank you very much in deed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;my wrfinput file format:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;netcdf wrfinput_d01 {&#xA;dimensions:&#xA;        Time = UNLIMITED ; // (1 currently)&#xA;        **DateStrLen = 19 ;**      **???????**&#xA;        west_east = 173 ;       **??????**&#xA;        south_north = 124 ;        **???????**&#xA;        bottom_top = 64 ;&#xA;        bottom_top_stag = 65 ;&#xA;        soil_layers_stag = 4 ;&#xA;        west_east_stag = 174 ;&#xA;        south_north_stag = 125 ;&#xA;        DIM0009 = 5 ;&#xA;        land_cat_stag = 21 ;&#xA;        soil_cat_stag = 16 ;&#xA;        num_ext_model_couple_dom_stag = 1 ;&#xA;        dust_erosion_dimension = 3 ;&#xA;        klevs_for_fire = 1 ;&#xA;variables:&#xA;float TH2(Time, south_north, west_east) ;&#xA;                TH2:FieldType = 104 ;&#xA;                TH2:MemoryOrder = &quot;XY &quot; ;&#xA;                TH2:description = &quot;POT TEMP at 2 M&quot; ;&#xA;                TH2:units = &quot;K&quot; ;&#xA;                TH2:stagger = &quot;&quot; ;&#xA;                TH2:coordinates = &quot;XLONG XLAT XTIME&quot; ;&#xA;.&#xA;.&#xA;.&#xA;// **global attributes: ?????????????????????**&#xA;                :TITLE = &quot; OUTPUT FROM REAL_EM V3.9.1.1 PREPROCESSOR&quot; ;&#xA;                :START_DATE = &quot;2010-08-28_12:00:00&quot; ;&#xA;                :SIMULATION_START_DATE = &quot;2010-08-28_12:00:00&quot; ;&#xA;                :WEST-EAST_GRID_DIMENSION = 174 ;&#xA;                :SOUTH-NORTH_GRID_DIMENSION = 125 ;&#xA;                :BOTTOM-TOP_GRID_DIMENSION = 65 ;&#xA;                :DX = 30000.f ;&#xA;                :DY = 30000.f ;&#xA;                :GRIDTYPE = &quot;C&quot; ;&#xA;                :DIFF_OPT = 2 ;&#xA;                :KM_OPT = 4 ;&#xA;                :DAMP_OPT = 0 ;&#xA;                :DAMPCOEF = 0.2f ;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;///////////////////////////////my netcdf file:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;dimensions:&#xA;        Lon = 21452 ;&#xA;        Lat = 21452 ;&#xA;        Time = UNLIMITED ; // (1 currently)&#xA;variables:&#xA;        double Lon(Lon) ;&#xA;                Lon:units = &quot;degrees&quot; ;&#xA;                Lon:long_name = &quot;Lon&quot; ;&#xA;        double Lat(Lat) ;&#xA;                Lat:units = &quot;degrees&quot; ;&#xA;                Lat:long_name = &quot;Lat&quot; ;&#xA;        double Time(Time) ;&#xA;                Time:units = &quot;days since 2010-08-28&quot; ;&#xA;                Time:long_name = &quot;Time&quot; ;&#xA;        float E_CO2(Time, Lat, Lon) ;&#xA;                E_CO2:units = &quot;mol km**-2 hr**-1&quot; ;&#xA;                E_CO2:_FillValue = 1.e+30f ;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;/////////////////////////////////////////////////////////&lt;/p&gt;&#xA;&#xA;&lt;p&gt;it hasn't the same attribute  &lt;/p&gt;&#xA;" OwnerUserId="18881" OwnerDisplayName="sara" LastEditorUserId="5594" LastEditDate="2020-03-13T14:15:22.967" LastActivityDate="2020-03-13T14:15:22.967" Title="how can I write my netCDF file in my wrfinput_d01 format" Tags="|netcdf|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="19453" PostTypeId="1" CreationDate="2020-03-13T10:01:18.070" Score="1" ViewCount="315" Body="&lt;p&gt;What dating method was used to determine the beginning of the Cambrian, and what was its margin of error? Was only one fossil dated, or were a number of similar fossils used?&lt;/p&gt;&#xA;" OwnerUserId="17166" LastEditorUserId="17166" LastEditDate="2020-03-13T10:11:57.580" LastActivityDate="2020-06-17T13:02:07.640" Title="How was the onset of the Cambrian period dated?" Tags="|earth-history|fossils|stratigraphy|dating|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19454" PostTypeId="1" CreationDate="2020-03-14T01:51:47.327" Score="1" ViewCount="57" Body="&lt;p&gt;&lt;a href=&quot;https://ageofrocks.wordpress.com/2015/03/16/monday-minute-300-million-year-old-fossils-from-the-bellies-of-100-million-year-old-dragons/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; describes gastroliths (&quot;stomach stones&quot;). It says that gastroliths have been found inside the rib cages of fossilized creatures such as dinosaurs. It also says that gastroliths sometimes contain fossils of older organisms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Have any examples been found where both these things are true?&lt;/p&gt;&#xA;" OwnerUserId="18728" LastActivityDate="2020-03-14T01:51:47.327" Title="Have fossil-containing gastroliths been found inside other fossils?" Tags="|fossils|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19455" PostTypeId="2" ParentId="19442" CreationDate="2020-03-14T02:25:51.170" Score="6" Body="&lt;p&gt;You can see &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13391/where-do-bad-smells-eventually-go/13392#13392&quot;&gt;this post&lt;/a&gt; for a more detailed discussion, but the typical answer to your question is air stagnation.  When the atmosphere is stable, there is little mixing, and the air can stagnate.  Typically this coincides with low wind speeds and a low boundary layer.  The boundary layer holds air near the surface like a blanket. The boundary layer collapses overnight, becoming shallow, and grows when the sun heats the surface of the Earth.  So, in the morning, the shallow boundary layer allows less vertical mixing to occur.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You might be noticing that on cloudy days, when clouds are low, there is little wind and no solar heating.  Air pollution has no place to go, so it sticks around.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another aspect is that vehicles emit more emissions under cold-start conditions.  This is because vehicles get cold overnight and take a while to get up to normal temperature when they startup in the morning.  The cold vehicle will have a low combustion efficiency and catalytic converters won't work as well. &lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2020-03-14T02:25:51.170" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19456" PostTypeId="1" AcceptedAnswerId="19458" CreationDate="2020-03-14T05:19:34.647" Score="3" ViewCount="309" Body="&lt;p&gt;&lt;a href=&quot;https://astronomy.stackexchange.com/questions/34219/did-nobody-in-the-astronomy-community-think-12-000-new-satellites-in-leo-might-b?noredirect=1#comment68924_34219&quot;&gt;This comment&lt;/a&gt; to &lt;em&gt;Did nobody in the Astronomy community think 12,000 new satellites in LEO might be a problem?&lt;/em&gt; links to Phys.org's &lt;a href=&quot;https://phys.org/news/2020-03-eso-impact-satellite-constellations-astronomical.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;New ESO study evaluates impact of satellite constellations on astronomical observations&lt;/a&gt; which includes ESO's &lt;a href=&quot;https://www.eso.org/public/switzerland-it/images/eso2004a/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Areas of the sky most affected by satellite constellations&lt;/a&gt; shown below.&lt;/p&gt;&#xA;&lt;p&gt;It's a fisheye lens view (FOV wider than 180 degrees)looking straight up.&lt;/p&gt;&#xA;&lt;p&gt;There is an large arc that begins at the bottom of the image (where the elevations of 20 and 30 degrees are deonted) and extends upward and toward the left. It looks like it could be a circle about the anti-lunar point since the moon is also seen on the right side slightly above center.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What is happening here? Is this an atmospheric effect of scattered moonlight? If so, what causes such a sharp transition in the amount of scattered light? Does this have a name?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aZNZU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aZNZU.jpg&quot; alt=&quot;the night sky at ESO's Paranal Observatory around twilight, about 90 minutes before sunrise Crediti: ESO/Y. Beletsky/L. Calçada&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This annotated image shows the night sky at ESO's Paranal Observatory around twilight, about 90 minutes before sunrise. The blue lines mark degrees of elevation above the horizon.&lt;/p&gt;&#xA;&lt;p&gt;A new ESO study looking into the impact of satellite constellations on astronomical observations shows that up to about 100 satellites could be bright enough to be visible with the naked eye during twilight hours (magnitude 5–6 or brighter). The vast majority of these, their locations marked with small green circles in the image, would be low in the sky, below about 30 degrees elevation, and/or would be rather faint. Only a few satellites, their locations marked in red, would be above 30 degrees of the horizon — the part of the sky where most astronomical observations take place — and be relatively bright (magnitude of about 3–4). For comparison, Polaris, the North Star, has a magnitude of 2, which is 2.5 times brighter than an object of magnitude 3.&lt;/p&gt;&#xA;&lt;p&gt;The number of visible satellites plummets towards the middle of the night when more satellites fall into the shadow of the Earth, represented by the dark area on the left of the image. Satellites within the Earth's shadow are invisible.&lt;/p&gt;&#xA;&lt;p&gt;Crediti: ESO/Y. Beletsky/L. Calçada&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2023-08-29T12:30:18.887" Title="What causes this arc in the night sky where the background is brighter on one side than the other?" Tags="|atmosphere|astronomy|identification-request|atmospheric-optics|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="19457" PostTypeId="2" ParentId="9977" CreationDate="2020-03-14T05:36:37.520" Score="0" Body="&lt;p&gt;I feel that before tectonic plate movement Kali Gandaki was flowing northword in Tethys ocean which got separated in the form of Mansarovar sweet water of river, whereas Rakastal is pushed up waters of Tethys ocean which has to be salty.&lt;a href=&quot;https://i.stack.imgur.com/dyUDH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dyUDH.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="19135" LastEditorUserId="19135" LastEditDate="2020-03-21T05:27:41.647" LastActivityDate="2020-03-21T05:27:41.647" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19458" PostTypeId="2" ParentId="19456" CreationDate="2020-03-14T17:37:23.440" Score="4" Body="&lt;p&gt;What is happening here? Photoshop!&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The number of visible satellites plummets towards the middle of the night when more satellites fall into the shadow of the Earth, &lt;strong&gt;represented by the dark area on the left of the image&lt;/strong&gt;. (emphasis added)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="19137" LastActivityDate="2020-03-14T17:37:23.440" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19460" PostTypeId="1" CreationDate="2020-03-15T12:46:18.013" Score="1" ViewCount="37" Body="&lt;p&gt;Yesterday, I received my census questionnaire. So have many millions of other Americans, recently.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These bags are not labeled for recycling, but are they recyclable? Can I put them in the deposits at my local grocery store with other bags marked &quot;4?&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Allow me to officially protest manufacturers of plastic that don't label them for recycling)&lt;/p&gt;&#xA;" OwnerUserId="19140" LastActivityDate="2020-03-15T12:46:18.013" Title="Recycling census plastic bags" Tags="|plastic|" AnswerCount="0" CommentCount="3" ClosedDate="2020-03-15T17:55:18.267" ContentLicense="CC BY-SA 4.0" />
  <row Id="19461" PostTypeId="2" ParentId="19322" CreationDate="2020-03-15T14:17:05.310" Score="-1" Body="&lt;p&gt;mindat.org  - * my fav as an avid rockhound/gem junkie&lt;/p&gt;&#xA;&#xA;&lt;p&gt;USGS.gov&lt;/p&gt;&#xA;&#xA;&lt;p&gt;geology.com&lt;/p&gt;&#xA;&#xA;&lt;p&gt;TreasureNet   is cool - you send pic (good) in app and the guy returns PDQ&lt;/p&gt;&#xA;&#xA;&lt;p&gt;*p.s.   ---  dont forget    *specific gravity test&lt;/p&gt;&#xA;" OwnerUserId="19142" LastActivityDate="2020-03-15T14:17:05.310" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19462" PostTypeId="1" AcceptedAnswerId="19463" CreationDate="2020-03-15T21:09:54.603" Score="4" ViewCount="1250" Body="&lt;p&gt;I'm currently reading a university textbook on processes that result in rainfall events. In the current processes, I'm reading there is a cold front that basically pushes warm air upwards which results in pretty heavy rain. A little before that, the process that a warm front basically moves above cold air which results in winter rain with a long duration. In the textbook I find the following sentences: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Typically, cold fronts have relatively steep slopes, about 1 in 30 to 40, while warm fronts have slopes of 1 in 60 to 120; thus precipitation is usually more intense and areally more concentrated at cold fronts than at warm fronts. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What means &quot;1 in 30&quot;? Could it be 1/30 = 0.0333 = 3.3% ? 1 in 60 = 1/60 = 0.016666 = 1.7%. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;That would result in a steeper slope for cold fronts. Is my understanding correct? Is a 2-3% slope for warm air pushed by cold fronts realistic?&lt;/p&gt;&#xA;" OwnerUserId="18169" LastEditorUserId="2470" LastEditDate="2020-03-16T05:17:51.470" LastActivityDate="2020-03-16T05:17:51.470" Title="&quot;steep slope&quot; when cold fronts encounter warm fronts: Confusing sentence in textbook" Tags="|meteorology|climatology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19463" PostTypeId="2" ParentId="19462" CreationDate="2020-03-16T00:41:27.493" Score="7" Body="&lt;p&gt;The slope is the ratio of the vertical to horizontal distance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;http://ww2010.atmos.uiuc.edu/(Gh)/wwhlpr/front_hyd.rxml&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;Warm fronts have a gentler slope and generally move more slowly than cold fronts, so the rising motion along warm fronts is much more gradual.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;You can see the steep slope of a cold front visualized, &lt;a href=&quot;https://i.stack.imgur.com/y82XJ.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/y82XJ.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and a more gradual slope for the warm front:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tGZca.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tGZca.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But depending on the source, there seems to be varying definitions of what the slope value actually is.  It makes sense, given that the answer would be different depending on how deep you go into the front and there would be seasonal variability.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.e-education.psu.edu/meteo3/l7_p5.html&quot; rel=&quot;noreferrer&quot;&gt;This site&lt;/a&gt; has a nice example:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;The cold front is steepest in the lowest several hundred meters of the atmosphere with a slope of about 1/100, meaning that elevation increases about 1 kilometer for every 100 kilometers of horizontal distance from the surface front. Then the upward slant relaxes into a much more gentle slope (e.g. 1/300). All along the upward slant of the cold wedge, cold air abuts with warmer air, creating an upward-slanting boundary characterized by large temperature contrasts.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UjOEm.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UjOEm.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2020-03-16T00:41:27.493" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19464" PostTypeId="2" ParentId="18243" CreationDate="2020-03-16T09:05:13.613" Score="2" Body="&lt;p&gt;You can definitely try to use &lt;a href=&quot;http://www.earthstat.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earthstat.org&lt;/a&gt; and try to recalculate these spatial values with data from &lt;a href=&quot;http://www.fao.org/faostat/en/&quot; rel=&quot;nofollow noreferrer&quot;&gt;FAOSTAT&lt;/a&gt;. Other possible data source could be &lt;a href=&quot;http://www.fao.org/nr/gaez/en/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Agroecological zones&lt;/a&gt;. Hope that will help!&lt;/p&gt;&#xA;" OwnerUserId="18631" LastActivityDate="2020-03-16T09:05:13.613" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19465" PostTypeId="2" ParentId="18243" CreationDate="2020-03-16T10:02:47.660" Score="4" Body="&lt;p&gt;In case you cannot access official local data, I recommend the use of the IFPRI resource &lt;a href=&quot;https://www.mapspam.info/&quot; rel=&quot;nofollow noreferrer&quot;&gt;MapSPAM2010&lt;/a&gt;. &#xA;Quoting the description of the dataset: &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Using a variety of inputs, IFPRI's Spatial Production Allocation Model (SPAM) uses a cross-entropy approach to make plausible estimates of crop distribution within disaggregated units. Moving the data from coarser units such as countries and sub-national provinces, to finer units such as grid cells, reveals spatial patterns of crop performance, creating a global grid-scape at the confluence between geography and agricultural production systems. Improving spatial understanding of crop production systems allows policymakers and donors to better target agricultural and rural development policies and investments, increasing food security and growth with minimal environmental impacts.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The dataset makes available data about agricultural variables for 42 crops at 10km resolution for the whole world. More info are available in the &lt;a href=&quot;https://www.mapspam.info/data/&quot; rel=&quot;nofollow noreferrer&quot;&gt;MapSPAM website&lt;/a&gt;, while the full dataset is available &lt;a href=&quot;https://dataverse.harvard.edu/dataset.xhtml?persistentId=doi:10.7910/DVN/PRFF8V&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;: International Food Policy Research Institute, 2019, &quot;Global Spatially-Disaggregated Crop Production Statistics Data for 2010 Version 1.1&quot;, &lt;a href=&quot;https://doi.org/10.7910/DVN/PRFF8V&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.7910/DVN/PRFF8V&lt;/a&gt;, Harvard Dataverse, V3 &lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can download the global rasters and then clip the area you are interested in and make your own estimates regarding specific crops and production technologies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The information in this dataset, would help you to set up a relatively simple crop model, such as the &lt;a href=&quot;http://www.fao.org/aquacrop/en/&quot; rel=&quot;nofollow noreferrer&quot;&gt;FAO AquaCrop&lt;/a&gt;. This system, even with a approximative calibration, could help you to understand some of the impacts of the &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;meteorological factors on the agricultural yields.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="8087" LastEditorUserId="8087" LastEditDate="2020-03-16T13:50:26.753" LastActivityDate="2020-03-16T13:50:26.753" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19466" PostTypeId="2" ParentId="19322" CreationDate="2020-03-16T12:11:49.450" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is there such a reliable source so I can identify the stones by myself? &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Maybe.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Most semi-precious stones are various forms of quartz or silica (e.g., agate, citrine, etc). Quartz is very hard and will scratch glass. It is hard to scratch quartz. Therefore, this is a non-destructive way for identification of quartz. It usually takes a really good polish that lasts. Hardness is pretty much the best way to identify quartz and other varieties of silica, because they &lt;em&gt;visually look&lt;/em&gt; all so different.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apart from quartz, there are several things which are unmistakeable. Watermelon tourmaline, for example. But if you got something which is not quartz and is not obviously something else, it becomes extremely hard to teach yourself to identify it. Even experienced geologists will have a difficult time identifying the stone without resorting to (somewhat) destructive and expensive methods such as XRD, XRF, EDS, etc. The dealers often don't even know what they have. They bought it from someone who bought it from someone and who knows whether the miner actually knows what they're  mining.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-03-16T12:11:49.450" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19467" PostTypeId="2" ParentId="19394" CreationDate="2020-03-17T12:36:37.963" Score="1" Body="&lt;p&gt;Try to read something about Köppen climate classification. This classification among other things tries to distinguish between rainy and dry season for many areas. So, scientist needs to know the distribution of precipitation. Another possibility could be indices described in this &lt;a href=&quot;https://www.researchgate.net/publication/227316077_Appendix_A_critical_examination_of_rainfall_variability_measures_used_in_behavioral_ecology_studies&quot; rel=&quot;nofollow noreferrer&quot;&gt;scientific article&lt;/a&gt; on the ResearchGate.&lt;/p&gt;&#xA;" OwnerUserId="18631" LastActivityDate="2020-03-17T12:36:37.963" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19468" PostTypeId="2" ParentId="19453" CreationDate="2020-03-17T14:15:38.107" Score="4" Body="&lt;p&gt;Fossils are only in very rare cases dated directly, because they do not contain sufficient radioactive isotopes for dating.&#xA;Most geological periods are first and foremost defined by biostratigraphy- fossil assemblages, typically. &#xA;The Cambrian period starts with the Fortunian stage - this stage is defined by the appearance of a certain trace fossil in Fortuna peninsula, eastern Canada, but is correlable with similar formations world wide. The whole discussion on how this stage is defined is available &lt;a href=&quot;https://stratigraphy.org/gssps/fortunian&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&#xA;As outlined in this paper, in addition to fossils, the Fortunian stage hosts various volcanic rocks which contain zircons, which can be dated by U-Pb. The age of the actual boundary is then interpolated from these data.&lt;/p&gt;&#xA;" OwnerUserId="4783" LastEditorUserId="87" LastEditDate="2020-06-17T12:54:08.343" LastActivityDate="2020-06-17T12:54:08.343" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19469" PostTypeId="1" CreationDate="2020-03-17T14:41:03.460" Score="3" ViewCount="171" Body="&lt;p&gt;From a comment in another question here,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Oh, and a third factor: the added atmospheric CO2 does not magically&#xA;  go away once all the fossil fuels are burned. &lt;strong&gt;It will stay in the&#xA;  atmosphere for thousands of years, if not more, and will keep on&#xA;  heating things up&lt;/strong&gt;. Currently the ocean absorbs a lot of the increased&#xA;  heat, and since the circulation time to the deep ocean is 100 years or&#xA;  more, heating will keep on for quite a while.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/16163/how-much-could-earths-temperature-increase-by-the-time-we-run-out-of-oil-reserv&quot;&gt;How much could Earth's temperature increase by the time we run out of oil reserves?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But recent reports from ESA satellite and others says,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Air pollution over Italy is seeing a drop after the country introduced&#xA;  a nationwide lockdown in response to the novel coronavirus outbreak&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;New data from the European Space Agency’s (ESA) Copernicus Sentinel-5p&#xA;  satellite, which can measure &lt;strong&gt;concentrations of greenhouse gases and&#xA;  pollutants in the atmosphere&lt;/strong&gt;, shows that between Jan. 1 and March 11,&#xA;  concentrations of nitrogen dioxide over Italy fell dramatically&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;China has also shown a sharp &lt;strong&gt;reduction in pollution&lt;/strong&gt; and greenhouse gas&#xA;  emissions after travel bans and quarantines&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://thehill.com/changing-america/sustainability/environment/487808-italy-sees-drop-in-pollution-amid-coronavirus?fbclid=IwAR0iTa7VYP4kgA4rWIc5Mux6bR69dItGncBWSO4UZpQ3q793jDBwlb03Bok&quot; rel=&quot;nofollow noreferrer&quot;&gt;Italy sees drop in pollution&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now with this, you still could interpret that by reduction of pollution they only meant Nitrogen dioxide and excluded CO2, but from here,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.washingtonpost.com/climate-environment/2020/03/13/italy-emissions-coronavirus/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Italy emissions Coronavirus&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;This will have just a minor effect of global concentrations of CO2,&#xA;  &lt;strong&gt;unless it leads to a really long depression of the world economy&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Would pollution / greenhouse houses really take a lot of years to disappear from the atmosphere once people stop producing them?&lt;/p&gt;&#xA;" OwnerUserId="9635" LastEditorUserId="9635" LastEditDate="2020-03-17T19:08:44.663" LastActivityDate="2020-03-19T09:40:46.440" Title="Would pollution really take a lot of years to disappear from the atmosphere once people stop producing them?" Tags="|climate-change|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="19470" PostTypeId="2" ParentId="4513" CreationDate="2020-03-18T03:53:18.593" Score="1" Body="&lt;p&gt;Faults are everywhere, mostly sealed, active or not. The question is how do the hot fluid conduits stay open in some places and not others.  I am currently studying thermal (hot and others) spring distributions in many regions of the world, as well as fault zones, and hot spring conduits in fault zones. The fluid-rock interaction, and discrete flow channel maintenance is likely as important, if not more, than activity of faults.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Active fault's that slip do not necessarily create any more permeability in the whole fault zone in the upper few km depth. Fault activity changes over million years time scale, but we do not know how the permeability changes over that time scale.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We do not yet understand how the permeability structure or distribution in a fault zone evolves over time once the rock is fractured, and as the fault zone is exhumed to what is not outcrop or the upper 1km depth in the crust.  The damage zone did not form there.  In strike slip faults, it may have formed 100km away.  The damage, and permeability evolution is cumulative and not yet understood.  We only get glimpses.  Of the mapped Quaternary faults in USA and Japan, the number of test sites for permeability is about 0.1%, even if we generously give the &quot;tested segment&quot; 1km length.  Basically, we sampled only a very small number of faults and poorly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hot springs, and thermal springs in general, are very promising in giving more estimates of permeability in the upper crust, but more work is needed on this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have drilled several paleo-hot spring conduits that are still open, and hydrothermally altered fault zones that are 1km wide, and the flow channels appear to be dissolution macro-pore tubular type of channels within fairly wide mineral fills in former fractures, in faults that are mostly sealed.  Many hot spring orifices are not exactly or even near the faults that provide the main upflow of thermal plume, as flow can be along permeable strata, non-fault fracture zones (fractured dykes or along them - see Iceland), volcanic extensional fissures (not faults), smaller fault zones that intersect (many papers point to fault zone intersections as permeability maxima), and many other features.  The number of &quot;hot springs&quot; (at faults?) at the top of basement rock under sedimentary basins is likely large and unknown.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;We need to test more hot spring conduits, and faults, systematically, and combine this with detailed geophysical surveys, and get more unpublished data from the geothermal industry released to scientists.&lt;/p&gt;&#xA;" OwnerUserId="19150" LastActivityDate="2020-03-18T03:53:18.593" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19471" PostTypeId="1" AcceptedAnswerId="19651" CreationDate="2020-03-18T11:11:19.440" Score="3" ViewCount="1841" Body="&lt;p&gt;Just to give context, this was not my original question but one that I ended up stuck with while trying to find a cause for the following observation (which is almost universally true for temperate climates):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Places on the WEST coast of continents tend to have a higher precipitation in WINTER, while places on the EAST coast of continents have a higher precipitation in SUMMER &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To see this view the following maps &#xA;&lt;a href=&quot;http://www.city-data.com/forum/weather/2895681-driest-wettest-months-year-world-maps.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.city-data.com/forum/weather/2895681-driest-wettest-months-year-world-maps.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the region between 30 degrees and 60 degrees from the equator is the one that comes under the the influence of Westerlies, this is the relevant region to be considered on the map. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;To view just a couple examples of this phenomenon, see the precipitation pattern in&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/San_Francisco#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/San_Francisco#Climate&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Rabat#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Rabat#Climate&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;compared to&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Tallahassee,_Florida#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Tallahassee,_Florida#Climate&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Shanghai#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Shanghai#Climate&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The flow of moisture laden air is the primary determinant of precipitation. Due to the coriolis force, the air in the Northern hemisphere moves clockwise, and the air in the Southern hemisphere moves counter-clockwise. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As the main prevailing winds causing rainfall on the WEST coast of continents is coming from the WEST , it must have been moving polewards, then bent East due to the coriolis force (Westerlies)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus, there must be some reason why the Westerlies are stronger in Winter. The only possible explanation I could  think of is that the pressure over the poles is higher in Summer (causing weaker pleward westerlies) and lower in Winter (causing stronger poleward westerlies)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This claim is in fact true, as is substantiated by Wikipedia.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Westerlies&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Westerlies&lt;/a&gt; This page states that the pressure over the poles is lower during Winter causing stronger Westerlies:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&quot;The westerlies are strongest in the winter hemisphere and times when the pressure is lower over the poles, while they are weakest in the summer hemisphere and when pressures are higher over the poles.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the same wikipedia page, it states the claim I am asking an explanation for:&#xA;&quot; This occurs when the Arctic oscillation is positive, and during winter low pressure near the poles is stronger than it would be during the summer&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like an explanation of this phenomenon, ideally explaining why the polar pressure varies to such an extent...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, I would like to know if the logic I have used to reach these conclusion is valid&lt;/p&gt;&#xA;" OwnerUserId="19151" LastEditorUserId="19151" LastEditDate="2020-04-15T10:16:29.097" LastActivityDate="2020-04-29T16:23:43.197" Title="Why is the pressure on the poles higher in Summer and lower in Winter?" Tags="|meteorology|atmospheric-circulation|coriolis|jet-stream|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="19472" PostTypeId="1" AcceptedAnswerId="19476" CreationDate="2020-03-18T14:00:58.943" Score="4" ViewCount="64" Body="&lt;p&gt;Trying to verify the validity of a rumor. &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/eventpage/uu60363602/executive&quot; rel=&quot;noreferrer&quot;&gt;https://earthquake.usgs.gov/earthquakes/eventpage/uu60363602/executive&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="19154" LastEditorUserId="6031" LastEditDate="2020-03-18T15:41:35.300" LastActivityDate="2020-03-19T14:46:31.573" Title="Could the 5.7 earthquake in Utah be a precursor to a larger one?" Tags="|earthquakes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19473" PostTypeId="2" ParentId="19469" CreationDate="2020-03-18T16:27:25.660" Score="5" Body="&lt;p&gt;[I apologise for this long &amp;amp; somewhat scrappy answer.  It may contain significant errors, for which I apologise as well.]&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How long something persists in the atmosphere once it's there depends, obviously, on how it gets removed from the atmosphere and also if anything is adding it to the atmosphere.  Different things we might consider pollutants will have different lifetimes, often very different, and it's confusing to lump them together as 'pollution'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However there is a very important distinction to be made:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;one thing we could care about is 'how long do we expect an individual atom/molecule/particle of &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; to remain in the atmosphere before it leaves it?'&lt;/li&gt;&#xA;&lt;li&gt;another thing we might care about is 'how should we expect the concentration of &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; to behave in the atmosphere over time?'&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;These two things &lt;em&gt;are not the same&lt;/em&gt;.  They are not the same because, even considering only 'natural' processes (which we might define as 'processes not resulting from the burning of fossil fuels or industrial activity') absorption is not all that happens: emission &lt;em&gt;also&lt;/em&gt; happens.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The thing that is interesting to know is generally the second: 'how does the concentration of &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; go over time?'  That's because no-one actually cares whether a given unit of something stays in the atmosphere for long: they care about &lt;em&gt;how much of it there is in the atmosphere&lt;/em&gt;: I don't care whether I'm breathing some particular oxygen molecules, I care that there is enough oxygen in the atmosphere that I can breathe.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Removal mechanisms&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;There are at least three mechanisms for removing something from the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;It may not be stable in the atmosphere.  A good example of this is methane, which gets turned into other things over a few years.  If methane emissions (including natural ones) stopped it would essentially all disappear within a few decades at most.&lt;/li&gt;&#xA;&lt;li&gt;It may leave the atmosphere by falling out of it or by being involved in precipitation.  This is true for aerosols (particulates) in the atmosphere: aerosols with large particle sizes really fall out of the atmosphere, aerosols with very small particle sizes get removed by precipitation and intermediate size ones experience both processes.&lt;/li&gt;&#xA;&lt;li&gt;It may get actively absorbed by something on the surface.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;A fourth mechanism is 'it may escape to space' but this is not a significant process anything interesting here, so I'll ignore it.  There may be other mechanisms I have not remembered.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Addition mechanisms&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;There are, I think, two significant mechanisms for creating stuff in the atmosphere:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;it may be emitted by something on the surface;&lt;/li&gt;&#xA;&lt;li&gt;it may be created by some process in the atmosphere.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;(And again, it may arrive from space, but I'll ignore that.)&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;How long things persist in the atmosphere&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;So, now, how long things persist in the atmosphere depends on what they are: the term 'pollution' bundles together things which have radically different characteristics.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Human-generated aerosols (smoke, other aerosols) have relatively short lifetimes in the atmosphere and are not created by processes in the atmosphere, and so will fairly quickly decline in concentration once emission stops.&lt;/li&gt;&#xA;&lt;li&gt;Aerosols of water – clouds – &lt;em&gt;are&lt;/em&gt; created in the atmosphere, from water vapour which will continue to be emitted from the surface, and are also removed from the atmosphere as rain, but these processes balance out over time and so clouds will persist in the atmosphere.  Clouds are not a pollutant of course: I just wanted to add them as another type of aerosol with another lifecycle in the atmosphere.&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$\mathrm{NO_x}$&lt;/span&gt; has a relatively short lifetime in the atmosphere as it's not stable: its lifetime in the lower atmosphere is hours, and in the upper is not more than few weeks.  Some &lt;span class=&quot;math-container&quot;&gt;$\mathrm{NO_x}$&lt;/span&gt; is created in the atmosphere by lightning, but I think the quantities are rather small compared to the amounts created by human emissions.  So the amount in the atmosphere will decline pretty quickly once emission from the surface stops.&lt;/li&gt;&#xA;&lt;li&gt;and so on.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;h2&gt;The elephant in the room: &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt;&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt;:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;is pretty much chemically stable and so does not decay in the atmosphere (it does undergo processes of being dissolved in water droplets and then evaporating from them, and perhaps others);&lt;/li&gt;&#xA;&lt;li&gt;is not an aerosol and so does not leave the atmosphere by the mechanisms which affect aerosols, unless it is dissolved in aerosols of water;&lt;/li&gt;&#xA;&lt;li&gt;is absorbed by several processes on the surface;&lt;/li&gt;&#xA;&lt;li&gt;is also emitted by several natural processes on the surface.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The things which absorb &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; on the surface are, among others (not necessarily in order):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;plants, which absorb &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; and turn it into plant and oxygen;&lt;/li&gt;&#xA;&lt;li&gt;the oceans, which dissolve &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt;;&lt;/li&gt;&#xA;&lt;li&gt;rock weathering;&lt;/li&gt;&#xA;&lt;li&gt;other things.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The natural (see above definition!) processes which emit &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; are (not in order):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;plants and animals which respire;&lt;/li&gt;&#xA;&lt;li&gt;plants (and animals) which die &amp;amp; decay or catch fire, releasing &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; back to the atmosphere;&lt;/li&gt;&#xA;&lt;li&gt;the oceans, which release dissolved &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; back to the atmosphere;&lt;/li&gt;&#xA;&lt;li&gt;vulcanism;&lt;/li&gt;&#xA;&lt;li&gt;other things.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;So in order to know how &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; behaves over time we need to understand how the various processes work: how fast is &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; cycled through the atmosphere and how fast does the concentration change.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Understanding this is not simple, and it's why people write big climate and earth system models.  But it's possible to give ballpark numbers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer to the first question: 'how long does an individual &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; molecule spend in the atmosphere' is 'a few years'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The answer to the second question: 'how long would it take for &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; concentrations to decline to preindustrial levels if fossil-fuel burning stopped, is 'from a few hundred to a few thousand years'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason for the large difference between these numbers is that the natural processes that absorb and emit &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; are very close to being in balance.  This is easy to see because we know that the concentration of &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; in the atmosphere was not zero before we started burning fossil fuels.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Just to give some figures (these are not meant to be accurate):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;plants absorb about &lt;span class=&quot;math-container&quot;&gt;$120\,\mathrm{GtC/y}$&lt;/span&gt; through photosynthesis;&lt;/li&gt;&#xA;&lt;li&gt;plants emit about &lt;span class=&quot;math-container&quot;&gt;$60\,\mathrm{GtC/y}$&lt;/span&gt; through respiration;&lt;/li&gt;&#xA;&lt;li&gt;about &lt;span class=&quot;math-container&quot;&gt;$60\,\mathrm{GtC/y}$&lt;/span&gt; is emitted from decay of plant matter;&lt;/li&gt;&#xA;&lt;li&gt;the oceans absorb about &lt;span class=&quot;math-container&quot;&gt;$90\,\mathrm{GtC/y}$&lt;/span&gt;;&lt;/li&gt;&#xA;&lt;li&gt;the oceans emit about &lt;span class=&quot;math-container&quot;&gt;$90\,\mathrm{GtC/y}$&lt;/span&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;As it stands this is completely balanced.  Well, these figures are approximate, and there are other processes both of absorption and emission.  But it's close to being in balance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is why the concentration of &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; would fall only rather slowly if fossil-fuel burning stopped.&lt;/p&gt;&#xA;" OwnerDisplayName="user18801" LastEditorDisplayName="user18801" LastEditDate="2020-03-19T09:40:46.440" LastActivityDate="2020-03-19T09:40:46.440" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19476" PostTypeId="2" ParentId="19472" CreationDate="2020-03-19T14:46:31.573" Score="6" Body="&lt;p&gt;Short answer: Yes, but the odds are small.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The USGS page that you linked to also links to a &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/eventpage/uu60363602/oaf/commentary&quot; rel=&quot;noreferrer&quot;&gt;forecast&lt;/a&gt;: &quot;According to our forecast, over the next 1 Week there is a 1 % chance of one or more aftershocks that are larger than magnitude 5.7.&quot; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;USGS also notes:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;No one can predict the exact time or place of any earthquake,&#xA;  including aftershocks. Our earthquake forecasts give us an&#xA;  understanding of the chances of having more earthquakes within a given&#xA;  time period in the affected area. We calculate this earthquake&#xA;  forecast using a statistical analysis based on past earthquakes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2020-03-19T14:46:31.573" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19477" PostTypeId="1" CreationDate="2020-03-19T18:55:19.577" Score="5" ViewCount="105" Body="&lt;p&gt;Many of the worlds oldest megaliths are aligned with the cardinal points like the Great Pyramid which is said to be within an accuracy of better than four minutes of arc, or one-fifteenth of one degree and other megaliths which were solar/lunar, equinox/solstice aligned when built, would these various  megalithic alignments show the actual movement of tectonic plates they sit upon?&#xA;If the African plate is estimated to move 6-7mm per year would not the alignment of the Great Pyramid be affected? Thus proving the rate of movement of the said plate? And still it is said that the pyramid is of the same accuracy as when first measured by researchers/explorers.&lt;/p&gt;&#xA;" OwnerUserId="19157" LastEditorUserId="2470" LastEditDate="2020-03-19T21:50:27.870" LastActivityDate="2020-03-19T21:50:27.870" Title="Given the movement of the tectonic plates in the past 5,000 years, how can the alignments of megaliths around the planet still be accurate?" Tags="|tectonics|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="19478" PostTypeId="2" ParentId="19412" CreationDate="2020-03-21T00:10:29.143" Score="4" Body="&lt;p&gt;In the case of a ground looking radar, the cross-polarized signals HV and VH generally increase with surface roughness. For example, dense vegetation is one of the more depolarizing surface types because the polarization orientation of the emitted beam is scrambled over the course of multiple scattering interactions within the canopy before returning to the detector. Smoother surfaces can be thought of as having fewer (often just one) interactions and the corresponding signals are thus reflected to the detector predominately in their initial orientation (i.e. as HH or VV).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The cross-polarized signal also increases as scatters suspended in the atmosphere become less spherical in shape. This is particularly applicable in the interpretation of meteorological radar observations where it is used to estimate raindrop size, distinguish between solid and liquid precipitation and differentiate biological scatterers (e.g. flocks of birds) from hydrometers. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a fixed target, the return signals HV and VH will have equal intensity. This is a direct result of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Helmholtz_reciprocity&quot; rel=&quot;nofollow noreferrer&quot;&gt;principle of reciprocity&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="908" LastEditorUserId="908" LastEditDate="2020-03-21T04:06:00.697" LastActivityDate="2020-03-21T04:06:00.697" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19479" PostTypeId="1" CreationDate="2020-03-21T01:55:41.100" Score="3" ViewCount="24" Body="&lt;p&gt;I live in the SF Bay Area where many, but not all, geological features are oriented parallel to the San Andreas Fault. I was wondering if there’s a type of map where ridges are colored by compass orientation, so perhaps N-S features are blue and E-W features are yellow, with lots of gradations in between. Seems like it would help identify features produced by the same forces (at least as a first guess). Does this type of map exist? If so, what’s it called? If not, would it actually be useful?&lt;/p&gt;&#xA;" OwnerUserId="4611" LastActivityDate="2020-03-21T01:55:41.100" Title="Coloring maps by feature orientation" Tags="|tectonics|mapping|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19480" PostTypeId="1" AcceptedAnswerId="19485" CreationDate="2020-03-21T07:08:35.747" Score="4" ViewCount="2659" Body="&lt;p&gt;I read that Morocco/Western Sahara has 75% of the world's known phosphate reserves, but I couldn't find an explanation of what mineral is responsible for it and how it all ended up there.&lt;/p&gt;&#xA;" OwnerUserId="19163" LastEditorUserId="2470" LastEditDate="2021-08-28T10:16:48.823" LastActivityDate="2021-08-28T10:16:48.823" Title="Why does Morocco have so much phosphate?" Tags="|geology|mining|economic-geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19483" PostTypeId="1" CreationDate="2020-03-21T18:18:50.423" Score="2" ViewCount="263" Body="&lt;p&gt;after the NMO application we have stretch for far offset , i read a lot of articles but i can't have a complete idea how this phenomena is really created ! any one have a rich explanation ? &lt;/p&gt;&#xA;" OwnerUserId="19164" LastActivityDate="2020-05-21T13:24:47.727" Title="stretch phenomena after NMO application on seismic data" Tags="|geophysics|seismic|data-analysis|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19485" PostTypeId="2" ParentId="19480" CreationDate="2020-03-21T21:48:14.030" Score="2" Body="&lt;p&gt;The Earth's crust &lt;a href=&quot;https://pubs.usgs.gov/bul/1252d/report.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;contains an average of 0.27 percent&lt;/a&gt; P&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;5&lt;/sub&gt;. Most of it in the mineral &lt;a href=&quot;https://en.wikipedia.org/wiki/Apatite&quot; rel=&quot;nofollow noreferrer&quot;&gt;apatite&lt;/a&gt; Ca&lt;sub&gt;10&lt;/sub&gt;(PO&lt;sub&gt;4&lt;/sub&gt;)&lt;sub&gt;6&lt;/sub&gt;(OH,F,Cl)&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Apatite is slowly soluble in neutral or alkaline waters, and its solubility increases with increasing acidity.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The PO&lt;sub&gt;4&lt;/sub&gt; content of most river and lake waters ranges from about 0.01 to 0.5 part per million (ppm), but may be much higher in soft acid waters and highly saline alkaline lakes. About one-sixth of the phosphate carried to the sea by runoff is in dissolved form. The ocean as a whole is nearly saturated with phosphate, but its distribution within the ocean is not uniform; deep cold waters contain nearly 0.3 ppm PO*, but warm surface waters contain only 0.01 ppm or less. Oceanic circulation brings phosphate- rich water to the surface in several environments, and phosphate may be precipitated either inorganically or biochemically, as the pH and temperature increase near the surface.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Most of the world's phosphate production comes from marine phosphorites, many of which are associated with black shale and chert. Secondary processes including diagenetic phosphatization of calcium carbonate and .interstitial precipitation, reworking by waves and currents, and weathering have often played a prominent part in forming deposits of mineable quality.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Common igneous rocks, such as granite, diorite, gabbro, and peridotite, contain only from about 0.005 to 0.4 percent P&lt;sub&gt;2&lt;/sub&gt;0&lt;sub&gt;5&lt;/sub&gt; ,  but some of the less common alkalic rocks, such as ijolite and turjaite, can contain more than 1  percent. Variations in phosphate content of igneous rocks generally parallel those of ilmenite and magnetite.Apatite is slowly soluble in neutral or alkaline waters, and its solubility increases with increasing acidity, decreasing hardness, and decreasing temperature.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Most phosphorus is carried to the sea as phosphate minerals or adsorbed on iron or aluminum hydroxides or clay.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Most of the world's phosphate production comes from marine phosphorites. The richest and largest of these form at low latitudes in areas of upwelling associated with divergence, chiefly along the west coasts of the continents or, in large mediterranean seas, along the equatorial side of the basin. Lesser but significant concentrations form along the west sides of poleward-moving warm currents along the eastern coasts of continents.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;In the &lt;a href=&quot;https://ui.adsabs.harvard.edu/abs/1972SedG....8....3S/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;Moroccan phosphate deposits&lt;/a&gt; however,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The unconsolidated sediments on the continental shelf and uppermost continental slope off Morocco and the Spanish Sahara are sands, silty sands, and silts. Their sand fraction is carbonate-rich and considered to be mainly relict from Pleistocene times when sea level was lower. This relict sand is mixed with, and locally buried by, Holocene detrital silts which are concentrated on the slope and the middle shelf. Phosphate is locally abundant in the form of sand-sized detrital grains. These were derived from Cretaceous and Tertiary phosphatic rocks cropping out on the shelf, by erosion during the Pleistocene. The sand-sized phosphatic detritus is concentrated in relict placer-type deposits near parent-rock outcrops. Longshore transport during the Pleistocene has contributed further concentrations of phosphatic sand along the shelf edge. These deposits are of low grade (&amp;lt; 8% P 2O 5) and are of no economic interest at present. No signs of Recent phosphate mineral formation were noted. Thus, the hypothesis that this phenomenon is linked with the upwelling of nutrient-rich water does not appear to apply, at this time, to the region studied. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-03-21T21:48:14.030" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19486" PostTypeId="2" ParentId="19322" CreationDate="2020-03-22T01:07:19.923" Score="0" Body="&lt;p&gt;As a student in petrology, I would say first you need to know if you gonna cut one thin slice out of this stone/rock, and this is usually how we identify an unknown rock. If so, you can refer to “A Key for Identification of Rock-Forming Minerals in Thin Section” by Andrew J. Barker to get a formal rock identification by observing thin section under optical microscope.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But if your stones are precious, then you might have to rely on observation of your raw samples. Key identifiers usually include :&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;color&lt;/li&gt;&#xA;&lt;li&gt;luster&lt;/li&gt;&#xA;&lt;li&gt;transparency,  &lt;/li&gt;&#xA;&lt;li&gt;hardness (using nail and knife)&lt;/li&gt;&#xA;&lt;li&gt;density (weighing by hand)&lt;/li&gt;&#xA;&lt;li&gt;cleavage (tendency to split along definite crystallographic structural planes)&lt;/li&gt;&#xA;&lt;li&gt;mineral fracture (a unique texture and shape of a rock's surface when fractured) &lt;/li&gt;&#xA;&lt;li&gt;mineral shape (sometimes related to crystallographic form, like large quartz&#xA;crystal)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The details should be easy to found in any textbook of Mineralogy and Petrology. Here is a book-list that I recommended for your reference: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://bookauthority.org/books/best-rock-identification-books&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://bookauthority.org/books/best-rock-identification-books&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="19167" LastActivityDate="2020-03-22T01:07:19.923" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19487" PostTypeId="1" AcceptedAnswerId="19489" CreationDate="2020-03-22T11:17:03.357" Score="26" ViewCount="5921" Body="&lt;p&gt;Is there a name for the great circle where latitude and longitude are equal? I have attempted a google search but only the equator and the prime meridian are defined in the sources I can find. ( It is of relevance in developing a map application which keeps track of latitude and longitude ).&lt;/p&gt;&#xA;" OwnerUserId="13314" LastActivityDate="2020-03-26T11:33:13.637" Title="Is there a name for the great circle where latitude and longitude are equal?" Tags="|geodesy|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19488" PostTypeId="1" AcceptedAnswerId="19491" CreationDate="2020-03-22T13:33:24.993" Score="4" ViewCount="64" Body="&lt;p&gt;This may be more of an age-dating question. When a meteorite travels through the Earth's atmosphere, I assume that it gets really hot.  Is the temperature of reentry hot enough to affect the radiometric dating process? Does heat influence the quality of radiometric dates, or does the rock have to completely melt to &amp;quot;reset to clock&amp;quot;?&lt;/p&gt;&#xA;&lt;p&gt;I have found similar questions on Earth Science:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/17965/how-can-radiometric-dating-of-meteorites-determine-the-age-of-the-earth-wouldn&quot;&gt;How can radiometric dating of meteorites determine the age of the earth? Wouldn&amp;#39;t this only determine the age of the decaying nuclide in each rock?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/2830/why-is-earths-age-given-by-dating-meteorites-rather-than-its-own-rocks&quot;&gt;Why is Earth&amp;#39;s age given by dating meteorites rather than its own rocks?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/2855/how-do-we-know-the-asteroids-formed-at-the-same-time-as-earth&quot;&gt;How do we know the asteroids formed at the same time as earth?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;But those don't quite answer the question I have.&lt;/p&gt;&#xA;" OwnerUserId="510" LastEditorUserId="510" LastEditDate="2021-07-22T17:26:42.660" LastActivityDate="2021-07-22T17:26:42.660" Title="Does the heat of reentry affect the reliability of radiometric dating of meteorites?" Tags="|meteorite|dating|age|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19489" PostTypeId="2" ParentId="19487" CreationDate="2020-03-22T13:54:00.183" Score="54" Body="&lt;p&gt;The curve where latitude and longitude are equal is not a great circle.  But as joe khool writes in his &lt;a href=&quot;https://earthscience.stackexchange.com/a/19502/18801&quot;&gt;excellent answer&lt;/a&gt;, it's called the &lt;strong&gt;curve of Viviani&lt;/strong&gt;!  It's easy to see that the curve is not a great circle, because, using naïve spherical coordinates (in radians) &lt;span class=&quot;math-container&quot;&gt;$(\phi,\lambda)$&lt;/span&gt; with &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt; being longitude and &lt;span class=&quot;math-container&quot;&gt;$\phi$&lt;/span&gt; being latitude (zero at equator), this curve passes through &lt;span class=&quot;math-container&quot;&gt;$(0,0)$&lt;/span&gt;, and also through &lt;span class=&quot;math-container&quot;&gt;$(\pi/2,\pi/2)$&lt;/span&gt; which is the north pole (&lt;span class=&quot;math-container&quot;&gt;$(\pi/2,\lambda)$&lt;/span&gt; is the north pole for any &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt;),  But it also passes through, say, &lt;span class=&quot;math-container&quot;&gt;$(1,1)$&lt;/span&gt; which is not on the great circle the between previous two points.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In fact the curve you get looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iF0y2.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iF0y2.png&quot; alt=&quot;not a great circle&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Note.&lt;/strong&gt; I plotted this by defining Cartesian coordinates in the obvious way:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\begin{align}&#xA; x &amp;amp;= R\cos\phi\cos\lambda\\&#xA; y &amp;amp;= R\cos\phi\sin\lambda\\&#xA; z &amp;amp;= R\sin\phi&#xA;\end{align}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and then plotting &lt;span class=&quot;math-container&quot;&gt;$(x,y,z)$&lt;/span&gt; for &lt;span class=&quot;math-container&quot;&gt;$\phi = \lambda$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\lambda\in[-\pi/2,\pi/2]$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An earlier version of this answer plotted &lt;span class=&quot;math-container&quot;&gt;$(x,y,z)$&lt;/span&gt; for &lt;span class=&quot;math-container&quot;&gt;$\phi = \lambda$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\lambda\in[-\pi,\pi]$&lt;/span&gt;.  This means that &lt;span class=&quot;math-container&quot;&gt;$\phi$&lt;/span&gt; takes values which are not in &lt;span class=&quot;math-container&quot;&gt;$[-\pi/2,\pi/2]$&lt;/span&gt; of course.  I had assumed that these points would end up around the back of the planet: that you'd get a kind of 'S' which wraps around the planet, but in fact it ends up around the front of it again:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/z34C2.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/z34C2.png&quot; alt=&quot;also not a great circle&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This surprised me!&lt;/p&gt;&#xA;" OwnerDisplayName="user18801" LastEditorUserId="19184" LastEditDate="2020-03-26T11:33:13.637" LastActivityDate="2020-03-26T11:33:13.637" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19490" PostTypeId="1" CreationDate="2020-03-22T18:13:37.243" Score="3" ViewCount="1222" Body="&lt;p&gt;My question pops-up from this question &amp;quot;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/580/why-does-lightning-strike-from-the-ground-up&quot;&gt;Why does lightning strike from the ground-up&lt;/a&gt;&amp;quot; which I consider partially unanswered.&lt;/p&gt;&#xA;&lt;p&gt;Why do I consider it partially unanswered?&lt;/p&gt;&#xA;&lt;p&gt;Because only one answer tried to explain why the difference of the several to one paths occur in this phenomenon.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Qp2PB.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Qp2PB.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;PS: there is another question that arises also&#xA;&lt;em&gt;&lt;strong&gt;Why does lightning strike from the ground up at this particular location in Earth and has it happened before (at the exact same location)?&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user19169" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-03-23T21:42:30.357" Title="Why does upwards lightning use only one path but downward lightning uses multiple paths?" Tags="|lightning|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19491" PostTypeId="2" ParentId="19488" CreationDate="2020-03-22T18:21:23.433" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://www.technologyreview.com/s/416009/do-nuclear-decay-rates-depend-on-temperature/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Current consensus&lt;/a&gt; says heat does not affect the rate of radioactive decay and if it does it is due to &lt;a href=&quot;https://physics.stackexchange.com/questions/400129/does-temperature-affect-nuclear-decay&quot;&gt;time dilation&lt;/a&gt;, the effect of whihc is very small. Thus the heating of meteorites as they enter Earth's atmosphere will not affect their radiometric dating.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-03-22T18:21:23.433" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19492" PostTypeId="2" ParentId="15558" CreationDate="2020-03-22T19:09:36.663" Score="1" Body="&lt;p&gt;for pipe, disk and fixed-block 8mm drives ,you need set param use_stdio=1&lt;/p&gt;&#xA;&#xA;&lt;p&gt;segdread tape=1.segd use_stdio=1 &gt; 1.su&lt;/p&gt;&#xA;" OwnerUserId="19170" LastActivityDate="2020-03-22T19:09:36.663" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19493" PostTypeId="1" CreationDate="2020-03-23T11:24:49.323" Score="4" ViewCount="81" Body="&lt;p&gt;The actions taken to contain the corona-virus epidemic is closing any form of human activities in the world. Schools are closed in most cities of the world, people are told to stay at home and it seems industries are also partially closed. So, chemical emissions from industries and cars will lower significantly. How does this affect the air quality, weather and climate?&lt;/p&gt;&#xA;" OwnerUserId="4877" LastActivityDate="2020-08-07T16:04:29.760" Title="How will air quality, weather and climate improve because of the containment, social distancing and lockdown during the COVID-19 outbreak?" Tags="|meteorology|atmosphere|climate|weather-forecasting|air-quality|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19494" PostTypeId="1" AcceptedAnswerId="19520" CreationDate="2020-03-23T11:35:00.477" Score="8" ViewCount="424" Body="&lt;p&gt;Browsing around Google Maps, I came across this off the south-west coast of Ireland&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/F9fWl.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/F9fWl.png&quot; alt=&quot;Continental shelf southwest of Ireland&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It looks very consistent with the shape rivers and their tributaries might make, but it has me puzzled since it's all underwater!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The main, most &quot;river-like&quot; one is in the middle-left of the picture but there are more (which look more like fjords) at the bottom.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What caused this feature?&lt;/p&gt;&#xA;" OwnerUserId="7682" LastEditorUserId="6298" LastEditDate="2022-02-06T17:29:51.990" LastActivityDate="2022-02-06T17:29:51.990" Title="What are these river/canyon-like carvings in the ocean?" Tags="|oceanography|rivers|satellite-oddities|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19495" PostTypeId="2" ParentId="19493" CreationDate="2020-03-23T13:32:51.710" Score="5" Body="&lt;p&gt;This is a topic of almost continual discussion in the South China Morning Post, scmp.com , an English language newspaper in Hong Kong. This is both because air quality is a major problem in China (but one to which they are paying a good deal of attention) and because massive economic interruptions are relatively frequent. The Olympics were a big one, national festivals like Spring Festival, 春节, Chūn jié, give readers a chance to mourn or hope, the current trade war modulates the scale of industry, and now we have Covid-19.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Obviously the virus crisis is bringing about great improvement in current air quality almost everywhere. I doubt that any climatic effects are known yet.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here's an article which introduces the topic in China -- which is, after all, the major live experiment going on: &lt;a href=&quot;https://www.scmp.com/news/china/society/article/3044747/beijings-air-quality-shows-significant-improvements-war&quot; rel=&quot;noreferrer&quot;&gt;https://www.scmp.com/news/china/society/article/3044747/beijings-air-quality-shows-significant-improvements-war&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="19176" LastActivityDate="2020-03-23T13:32:51.710" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19496" PostTypeId="1" CreationDate="2020-03-23T17:58:18.403" Score="1" ViewCount="85" Body="&lt;p&gt;in seismic data processing there is a step of calculating the absorption represented By Q value which is Q factor , how we can estimate it from VSP ! &#xA;thank you.&lt;/p&gt;&#xA;" OwnerUserId="19164" LastActivityDate="2021-06-30T15:52:37.460" Title="Q factor estimation from VSP" Tags="|geophysics|seismic|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19497" PostTypeId="2" ParentId="19490" CreationDate="2020-03-23T21:42:30.357" Score="3" Body="&lt;p&gt;Upwards stroke happens when the stepped leader and the traveling spark have already connected. This path then becomes much more conductive than any other paths where the connection hasn't happened yet—because the latter ones have gaps of non-ionized air inside them. This highly conductive path shunts all the remaining stepped leaders, lets the charges quickly cancel out, and thus basically stops propagation of the leaders.&lt;/p&gt;&#xA;" OwnerUserId="12360" LastActivityDate="2020-03-23T21:42:30.357" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19498" PostTypeId="2" ParentId="580" CreationDate="2020-03-23T22:38:19.967" Score="1" Body="&lt;p&gt;I won't repeat something provided in other answers. The only thing i would like to add is that &lt;strong&gt;&lt;em&gt;we don't see a Ground To Cloud Lightning&lt;/em&gt;&lt;/strong&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Theoretically speaking Ground To Cloud could be possible since lightning is a discharge between 2 points that have extreme voltage difference. So it is not a mystery &quot;why this happens&quot; as said in this &lt;a href=&quot;https://www.youtube.com/watch?v=RDDfkKEa2ls&quot; rel=&quot;nofollow noreferrer&quot;&gt;video&lt;/a&gt;, but 'how this happens&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it a case of Geology of the location (like &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Maracaibo&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Maracaibo&lt;/a&gt; or the lake of the thousand lightnings)? Yes and it is needed to examine more thoroughly since some effects do happen more frequently in certain geographical locations all it is needed to be understood is &lt;strong&gt;WHY&lt;/strong&gt; (and it could be not just one factor).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1Lpi1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1Lpi1.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;Map of average yearly lightning strikes per sq km from 1995 to 2013 (Credit: NASA)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;But to return to this picture&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Qp2PB.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Qp2PB.gif&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and please take a good look. Notice the bright flash on the top left corner at the beginning that spreads into several leaders reaching for the ground. No ground path been established until two of those leaders reach the ground. From those two paths one of them has less resistance leading to a momentary current path among the cloud and the ground. I do think that in this case we see a Cloud To Ground lightning but of these two types, &lt;a href=&quot;https://en.wikipedia.org/wiki/Lightning#Positive_and_negative_lightning&quot; rel=&quot;nofollow noreferrer&quot;&gt;positive and/or negative lightning&lt;/a&gt; on an already established path. The image is taken from an High Speed or Ultra High Speed Camera, capable of 10k-1m frames per second, what we see is very slow motion of a cloud discharge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Furthermore one thing you should have in mind is that lightning is not just a static electricity discharge. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&lt;strong&gt;&lt;em&gt;This discharge may produce a wide range of electromagnetic radiation,&#xA;  from very hot plasma created by the rapid movement of electrons to&#xA;  brilliant flashes of visible light in the form of black-body&#xA;  radiation. Lightning causes thunder, a sound from the shock wave which&#xA;  develops as gases in the vicinity of the discharge experience a sudden&#xA;  increase in pressure. Lightning occurs commonly during thunderstorms&#xA;  and other types of energetic weather systems, but volcanic lightning&#xA;  can also occur during volcanic eruptions.&lt;/em&gt;&lt;/strong&gt; &lt;a href=&quot;https://en.wikipedia.org/wiki/Lightning&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Above is written that the discharge itself may produce wide range of electromagnetic radiation.&#xA;The majority of that radiation should be produced once the Cloud To Ground path has been established. In case we do have a combination of positive and negative lightning on that path then perhaps a differently &lt;code&gt;filtered&lt;/code&gt;  view of this lightning (microwave, infrared, ultraviolet, or even X-ray range) would have been more &lt;code&gt;enlightening&lt;/code&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I actually don't think that all the radiation comes from the discharge itself as written above. &#xA;It should be a combination of static electricity and radiation even before the discharge, only to be amplified at the moment of discharge.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An even more peculiar case than Ground To Cloud lightning is also the case of &lt;a href=&quot;https://en.wikipedia.org/wiki/Ball_lightning&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ball Lightning&lt;/a&gt;. This &lt;a href=&quot;https://www.youtube.com/watch?v=cIB3NPTdwmc&quot; rel=&quot;nofollow noreferrer&quot;&gt;video&lt;/a&gt; shows something that could be identified as ball lightning. One of the theories on how ball lightning occur indicate that &lt;code&gt;Si&lt;/code&gt; element on soil could be a factor. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;EDIT&lt;/strong&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In order to prove my point on this optical illusion in the above image i add a link of another &lt;a href=&quot;https://www.youtube.com/watch?v=m6a2Qtu3728&quot; rel=&quot;nofollow noreferrer&quot;&gt;optical illusion&lt;/a&gt;, of course on that video the train has one and only course but we see it to have both, in cases like that the human brain finds other ways to determine the direction.&lt;/p&gt;&#xA;" OwnerDisplayName="user19169" LastEditorDisplayName="user19169" LastEditDate="2020-05-23T13:49:12.343" LastActivityDate="2020-05-23T13:49:12.343" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19499" PostTypeId="1" CreationDate="2020-03-23T23:55:59.777" Score="1" ViewCount="116" Body="&lt;p&gt;I want to use the evapotranspiration product, which one will be the suitable to show net evapotranspiration on large and arid area? Thanks&lt;/p&gt;&#xA;" OwnerUserId="19182" LastActivityDate="2020-04-06T14:24:39.887" Title="What is the difference between MOD16A2 and MOD16A2GF products?" Tags="|modis|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19502" PostTypeId="2" ParentId="19487" CreationDate="2020-03-24T07:16:00.810" Score="19" Body="&lt;p&gt;If the Earth was a sphere, then the curve in the last picture of tfb's answer is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Viviani%27s_curve#Parametric_representation&quot; rel=&quot;noreferrer&quot;&gt;curve of Viviani&lt;/a&gt;; otherwise, if you make the oblate spheroid assumption, you get a slightly distorted version of this curve.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;More generally, a &lt;a href=&quot;https://en.wikipedia.org/wiki/Cl%C3%A9lie&quot; rel=&quot;noreferrer&quot;&gt;&lt;em&gt;clélie&lt;/em&gt;&lt;/a&gt; is the name given to any spherical curve where the longitude &lt;span class=&quot;math-container&quot;&gt;$\varphi$&lt;/span&gt; and colatitude &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; have the relationship &lt;span class=&quot;math-container&quot;&gt;$\varphi=c\theta,\quad c&amp;gt;0$&lt;/span&gt;, and the curve of Viviani corresponds to the locus of a geosynchronous orbit, &lt;span class=&quot;math-container&quot;&gt;$c=1$&lt;/span&gt;.&lt;/p&gt;&#xA;" OwnerUserId="19184" LastEditorUserId="19184" LastEditDate="2020-03-24T07:22:38.587" LastActivityDate="2020-03-24T07:22:38.587" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19504" PostTypeId="2" ParentId="19483" CreationDate="2020-03-24T08:44:13.507" Score="4" Body="&lt;p&gt;My understanding is the following (NB: it could be wrong!). &lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The assumption is that on a common shot gather, your travel time follows a hyperbolic curve:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;f(x)=t^2=t_0^2 + \frac{x^2}{v^2},&#xA;$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$t_0$&lt;/span&gt; is the zero-offset travel time, &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; the offset and &lt;span class=&quot;math-container&quot;&gt;$v$&lt;/span&gt; the speed of the medium above the interface. The hyperbolic travel-times, for example, create gathers like the one shown in &lt;a href=&quot;https://wiki.seg.org/wiki/NMO_stretching#/media/File:Ch03_fig1-9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://wiki.seg.org/wiki/NMO_stretching#/media/File:Ch03_fig1-9.png&lt;/a&gt; (which is figure '(a)' below).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Furthermore, the recorded wavelet has the same shape along the time (&lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt;) direction, regardless of which offset (&lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt;) you recorded it. Hence, on the figure below, check that there is no discernible change in the wavelet shape in figure '(a)' below as you move along the hyperbolic curve.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Then, NMO correction essentially comes down to stretching the original data. In the figure '(a)' below, I put a red line close to the zero offset point, and a purple line at far offset. In figure '(b)', which is an NMO-corrected picture, I highlight that same lines, with identical colors. You see that the zero offset  (red line) hardly requires a change, but the far offset (purple line) needs to be stretched considerably to create a flat curve in the diagram! A neat feature is that at at ~90% of the offsets, you still see 2 events cross in both figures '(a)' and '(b)', to indeed confirm that we just stretch the traces with no real further magic behind it...&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;So, the wavelet shape is constant in the vertical direction everywhere in figure '(a)', but is seriously stretched out in figure '(b)'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From the &lt;a href=&quot;https://wiki.seg.org/wiki/NMO_stretching&quot; rel=&quot;nofollow noreferrer&quot;&gt;page of the linked figure&lt;/a&gt;: &quot;&lt;em&gt;Note that stretching is confined mainly to large offsets and shallow times. For example, a waveform with a 30-Hz dominant frequency at 2000-m offset and t0 = 0.25 s shifts to nearly 10 Hz after NMO correction. Because of the stretched waveform at large offsets, stacking the NMO-corrected CMP gather will severely damage the shallow events. This problem can be circumvented by muting the stretched zones in the gather.&lt;/em&gt;&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/L9DbZ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/L9DbZ.png&quot; alt=&quot;NMO example&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;tl;dr: because the red and purple line in figure '(a)' must become the red and purple line in figure '(b)', the wavelets of particularly the purple line are stretched.&lt;/p&gt;&#xA;" OwnerUserId="12155" LastActivityDate="2020-03-24T08:44:13.507" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19507" PostTypeId="2" ParentId="9642" CreationDate="2020-03-24T22:59:54.300" Score="1" Body="&lt;p&gt;Because longitudes run north south, I remember longitude with a rhyme of the first two letters of each: NoSoLo (&lt;strong&gt;No&lt;/strong&gt;rth &lt;strong&gt;So&lt;/strong&gt;uth &lt;strong&gt;Lo&lt;/strong&gt;ngitude).&lt;/p&gt;&#xA;" OwnerUserId="19197" LastEditorUserId="19197" LastEditDate="2020-03-24T23:18:24.963" LastActivityDate="2020-03-24T23:18:24.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19508" PostTypeId="2" ParentId="16881" CreationDate="2020-03-25T02:20:44.700" Score="2" Body="&lt;p&gt;Water has likely seeped in to the point of filling the hole up to sea level along with a high concentration of mineral deposits as a suspension of solids with the &lt;a href=&quot;https://www.atlasobscura.com/places/kola-superdeep-borehole?mc_cid=69025636df&amp;amp;mc_eid=34be11d5e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;180° Celsius bottom&lt;/a&gt; creating a lava lamp like movement of those solids as they cool near the surface. Also assuming they left the drill and shafts inside, a whole lot of rusting metal.&lt;/p&gt;&#xA;" OwnerUserId="19199" LastEditorUserId="27531" LastEditDate="2022-08-30T00:27:46.800" LastActivityDate="2022-08-30T00:27:46.800" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19510" PostTypeId="1" AcceptedAnswerId="19512" CreationDate="2020-03-25T08:14:49.713" Score="1" ViewCount="46" Body="&lt;p&gt;I am a beginner of learning Tropical Cyclone. I would like to represent the extratropical transition of a tropical cyclone. But I can't understand on what actually in need to focus.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a tropical cyclone, I can calculate time series of rainfall, maximum wind speed, minimum sea level pressure and discuss its features. Similarly, what are the quantities I should calculate to represent the extratropical transitions of the same tropical cyclone? and What actually I need to show? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it just simple discuss how a tropical cyclone changes its behavior when it moves toward the higher latitudes?&lt;/p&gt;&#xA;" OwnerUserId="3194" LastActivityDate="2020-03-25T18:09:56.370" Title="Extratropical transition of tropical cyclone" Tags="|tropical-cyclone|cyclone|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19511" PostTypeId="2" ParentId="19286" CreationDate="2020-03-25T14:48:24.413" Score="3" Body="&lt;p&gt;I think that your question is not really answerable.  But perhaps the reasons it's not answerable are themselves interesting.  There are two parts to this answer:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;why do we think abiogenisis is likely?&lt;/li&gt;&#xA;&lt;li&gt;is Earth, today, hospitable for organisms which originate through abiogenesis, if it is likely?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;My answer to the first part is, I think, more well-founded than my answer to the second (I'm a physicist not a biologist!).&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Is abiogenesis likely?&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Well, we have exactly one example of a planet we can study closely with life on it (indeed there is only one example of a planet that we know has life at all at present), and life has been there for such a long time and has modified the environment of that planet so extensively that I think speculation about how life originated on that planet is, well, speculation.  That doesn't mean it's not interesting or that there might not be plausible and attractive hypotheses.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an example it's tempting to argue that, because life originated on Earth almost as soon as it could, and disregarding panspermia, that abiogenesis must therefore be very common.  That argument is wrong.  There are a &lt;em&gt;huge&lt;/em&gt; number of potentially-earthlike planets: &lt;a href=&quot;http://dx.doi.org/10.3847/1538-3881/ab31ab&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; paper (&lt;a href=&quot;https://arxiv.org/abs/1902.01417&quot; rel=&quot;nofollow noreferrer&quot;&gt;arXiv version&lt;/a&gt;) claims that around 10% of stars may have a planet that is about the same size as Earth and gets around the same amount of sunlight as Earth.  There may be around &lt;span class=&quot;math-container&quot;&gt;$10^{24}$&lt;/span&gt; stars in the observable universe: based on &lt;a href=&quot;http://dx.doi.org/10.3847/0004-637X/830/2/83&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; paper (&lt;a href=&quot;https://arxiv.org/abs/1607.03909v2&quot; rel=&quot;nofollow noreferrer&quot;&gt;arXiv&lt;/a&gt;) there may be around &lt;span class=&quot;math-container&quot;&gt;$2\times 10^{12}$&lt;/span&gt; galaxies and assuming each galaxy has &lt;span class=&quot;math-container&quot;&gt;$10^{12}$&lt;/span&gt; stars we get &lt;span class=&quot;math-container&quot;&gt;$2\times 10^{23}$&lt;/span&gt; stars.  So this means perhaps &lt;span class=&quot;math-container&quot;&gt;$2\times 10^{22}$&lt;/span&gt; potentially-earthlike-planets.  All we know is that life originated on &lt;em&gt;one&lt;/em&gt; of those planets, somehow (and abiogenesis is only one of at least two options), and it did so rather early.  What does that tell us?  Well, statisticians can play games and those games are probably reasonable, but it doesn't tell us, for sure, that the chance of that happening is higher than &lt;span class=&quot;math-container&quot;&gt;$1/10^{22}$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This argument is related to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Anthropic%5C_principle&quot; rel=&quot;nofollow noreferrer&quot;&gt;anthropic principle&lt;/a&gt; which I find rather unappealing in terms of explanatory power: I find the idea that the fine-structure constant must be what it is because otherwise we would not be here to measure it unappealing for instance.  But the anthropic principle is nevertheless not an idea that can be ruled out in general: we know life evolved on Earth because we're here to observe it, but this doesn't, yet, tell us anything about the probability of life evolving elsewhere: the universe could have just thrown a &lt;span class=&quot;math-container&quot;&gt;$10^{22}$&lt;/span&gt;-sided dice &lt;span class=&quot;math-container&quot;&gt;$10^{22}$&lt;/span&gt; times and come up with the side that says 'life' once.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This doesn't mean that abiogenisis &lt;em&gt;can't&lt;/em&gt; be really common, or even that it not likely that it is, it just means that we don't &lt;em&gt;know&lt;/em&gt; that it is.  With luck this will change in the relatively near future, as we begin to be able to observe expolanets which convincingly have life.  Then we'll be able to use statistics in a more useful way.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;How hospitable is Earth, today?&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Well, let's assume abiogenisis &lt;em&gt;is&lt;/em&gt; common, what can we say about Earth's hospitability to new life generated that way?  Well, we know that organisms on Earth are continually under attack by other organisms and things which may be organisms (I'm not a biologist, I'm not sure if viruses count as organisms or not).  And we know that these attacks can be pretty successful: for instance when Cortés invaded what is now Mexico the population was around 25-30 million, 50 years later it was around 3 million, and most of this decline happened due to disease (&lt;a href=&quot;https://en.wikipedia.org/wiki/Native%5C_American%5C_disease%5C_and%5C_epidemics#Impact%5C_on%5C_population%5C_numbers&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So life on Earth exists in this continual arms-race: things try to attack organisms and organisms develop hugely sophisticated immune systems to deal with those attacks.  We're living, right now, through an example of what happens when an agent attacks us for which our immune system is not yet prepared: fortunately it's not going to kill that many of us.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So let's propose that abiogenesis happens on Earth, now.  There are really two options.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Whatever appears is, say, RNA-based, and as such is recognisable by the existing warring factions.  It has no defences and gets promptly attacked and eaten.&lt;/li&gt;&#xA;&lt;li&gt;Whatever appears is based on some significantly different chemistry.  But whatever it is, it's harvesting energy from somewhere and making it into itself.  As soon as it starts harvesting enough energy it becomes interesting to existing organisms who would be quite interested in getting that energy for themselves, who pretty quickly evolve to being able to do so and eat it.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The third option is that whatever it is turns out to be so efficient in some way that it wins the fight with the existing stuff.  I suspect, without any kind of proof, that this option is absurdly unlikely to happen.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I think what is more likely to happen is that, any time some new way of chemically stashing energy happens, it becomes attractive to existing organisms, who evolve to be able to harvest that energy and do so, long before whatever thing has happened could be described as 'alive'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In summary: Earth is almost certainly &lt;em&gt;not&lt;/em&gt; currently hospitable to newly-generated life, at all, because the existing life will eat it, one way or the other.&lt;/p&gt;&#xA;" OwnerDisplayName="user18801" LastActivityDate="2020-03-25T14:48:24.413" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19512" PostTypeId="2" ParentId="19510" CreationDate="2020-03-25T17:59:48.000" Score="2" Body="&lt;p&gt;No, it is not sufficient to just discuss the behavior as it moves into higher latitudes. ET occurs because of environmental reasons, not geographical reasons. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How much of a beginner are you? My answer below may be a bit over your head if you do not know much about tropical cyclones. If that is the case, I suggest looking back at the theory and &lt;a href=&quot;https://www.meted.ucar.edu/training_module.php?id=868#.XnubT4hKhPY&quot; rel=&quot;nofollow noreferrer&quot;&gt;basics&lt;/a&gt; of tropical cyclones (structure, maximum potential intensity, etc.) to get a good grasp of what separates tropical cyclones from extratropical cyclones. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you are specifically looking at quantities, I suggest looking at &lt;a href=&quot;https://journals.ametsoc.org/doi/full/10.1175/1520-0493%282003%29131%3C0585%3AACPSDF%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;cyclone phase space diagrams&lt;/a&gt;. The variables in these diagrams include the thermal wind for different levels, as well as baroclinicity. &lt;a href=&quot;http://moe.met.fsu.edu/cyclonephase/&quot; rel=&quot;nofollow noreferrer&quot;&gt;FSU has examples of cyclone phase space diagrams for different storms.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: I remembered two recent articles that review ET. They are &lt;a href=&quot;https://journals.ametsoc.org/doi/full/10.1175/MWR-D-17-0027.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Evans et al. (2017)&lt;/a&gt; and &lt;a href=&quot;https://journals.ametsoc.org/doi/full/10.1175/MWR-D-17-0329.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Keller et al. (2019)&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2020-03-25T18:09:56.370" LastActivityDate="2020-03-25T18:09:56.370" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19513" PostTypeId="1" AcceptedAnswerId="19522" CreationDate="2020-03-25T18:37:55.810" Score="2" ViewCount="94" Body="&lt;p&gt;I have a number of datasets that describe geological properties as intervals down a borehole (e.g. unit codes, sample results)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a database, or a flat ASCII file, I would describe these with a &lt;code&gt;from&lt;/code&gt; and a &lt;code&gt;to&lt;/code&gt; column, and then have a column for each observation type.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What (if any) is the guidance for storing this kind of data that represents an &lt;em&gt;interval&lt;/em&gt; within a netCDF. I've checked the &lt;a href=&quot;http://cfconventions.org/Data/cf-conventions/cf-conventions-1.8/cf-conventions.html#_description_of_the_data&quot; rel=&quot;nofollow noreferrer&quot;&gt;CF Conventions&lt;/a&gt;, notably the section on discrete sampling geometries but haven't been able to find anything. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The more I think about it, intuitively, it seems like the wrong file format but maybe I'm wrong.&lt;/p&gt;&#xA;" OwnerUserId="14348" LastActivityDate="2020-03-27T18:39:44.197" Title="Storing borehole interval data (logs) in netcdf" Tags="|geology|geography|data-formats|netcdf|" AnswerCount="1" CommentCount="3" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19514" PostTypeId="1" CreationDate="2020-03-25T21:17:42.800" Score="1" ViewCount="50" Body="&lt;p&gt;I am a staunch believer in the benefit of hand analyzing maps to get a good feel for the state of the atmosphere before getting into my forecast. With Covid-19 keeping us out of the office, one of the things I miss the most is being able to print out maps and hand analyze them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does anyone have any tips for analyzing maps without printing them out or alternatives to a hand analysis that you have had good experiences with?&lt;/p&gt;&#xA;" OwnerUserId="13660" LastActivityDate="2020-03-25T21:17:42.800" Title="Digital alternative to hand analyzed maps" Tags="|meteorology|weather-forecasting|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19515" PostTypeId="1" AcceptedAnswerId="19516" CreationDate="2020-03-26T00:44:28.283" Score="14" ViewCount="2577" Body="&lt;p&gt;Wikipedia's WikiNews' 2005 article &lt;a href=&quot;https://en.wikinews.org/wiki/Mars_Rover%E2%80%99s_Basketball-Shaped_Discovery_Stirs_Controversy&quot; rel=&quot;noreferrer&quot;&gt;Mars Rover’s Basketball-Shaped Discovery Stirs Controversy&lt;/a&gt; says:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The surface of the meteorite was found to be remarkably free of corrosion. Researchers are as yet unsure whether this means it arrived recently or that it has possibly been sandblasted thoroughly.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;and links to Space.com's &lt;a href=&quot;https://www.space.com/707-mars-rover-meteorite-discovery-triggers-questions.html&quot; rel=&quot;noreferrer&quot;&gt;Mars Rover's Meteorite Discovery Triggers Questions&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On earth we don't normally see clean, shiny iron surfaces because iron is easily oxidized in a short time even at room temperature by several oxidizing components of air. Some of these are present on Mars but of course at far lower in concentration, but there are other oxidizers including &lt;a href=&quot;https://en.wikipedia.org/wiki/Perchlorate&quot; rel=&quot;noreferrer&quot;&gt;perchlorate&lt;/a&gt;. Yet both iron meteorites discovered on Mars that I'm aware of (&lt;a href=&quot;https://en.wikipedia.org/wiki/Heat_Shield_Rock&quot; rel=&quot;noreferrer&quot;&gt;Heat Shield Rock&lt;/a&gt; and &lt;a href=&quot;https://skyandtelescope.org/astronomy-blogs/astronomy-space-david-dickinson/curiosity-examines-iron-meteorite-egg-rock/&quot; rel=&quot;noreferrer&quot;&gt;Egg Rock&lt;/a&gt;) look clean as do others shown in that Sky &amp;amp; Telescope article.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it known why? Have they landed so recently that oxidation hasn't had the time to make much change, or are they &lt;em&gt;sandblasted clean&lt;/em&gt; as &lt;a href=&quot;https://en.wikipedia.org/wiki/Karen_Steele&quot; rel=&quot;noreferrer&quot;&gt;Karen Steele&lt;/a&gt;'s character Eve McHuron told &lt;s&gt;Kirk&lt;/s&gt; one of the miners to do with a dirty cast-iron skillet&lt;sup&gt;†&lt;/sup&gt; on the storm-plagued planet Rigel XII.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Photos of these two meteorites taken by Curiosity can be seen in &lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://astronomy.stackexchange.com/a/31815/7982&quot;&gt;this answer&lt;/a&gt; to &lt;em&gt;What is the name of meteoroids which hit Moon, Mars, or pretty much anything that isn’t the Earth?&lt;/em&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://space.stackexchange.com/a/24660/12102&quot;&gt;this answer&lt;/a&gt; to &lt;em&gt;Who discovered “Egg Rock”? The Curiosity rover or people?&lt;/em&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Also see &lt;a href=&quot;https://mars.nasa.gov/resources/6433/curiosity-finds-iron-meteorite-on-mars/&quot; rel=&quot;noreferrer&quot;&gt;Curiosity Finds Iron Meteorite on Mars&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;sup&gt;†&lt;/sup&gt;from &lt;a href=&quot;https://scifi.stackexchange.com/a/229030/51174&quot;&gt;this answer&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LT9h0.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LT9h0m.jpg&quot; alt=&quot;dirty pans being sand-blasted clean on the storm-plagued planet Rigel XII.&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="2470" LastEditDate="2020-03-26T11:48:18.913" LastActivityDate="2020-03-26T11:58:35.123" Title="Why don't iron meteorites on Mars rust or oxidize? Why are they shiny?" Tags="|geochemistry|meteorite|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="19516" PostTypeId="2" ParentId="19515" CreationDate="2020-03-26T02:00:08.477" Score="12" Body="&lt;p&gt;&lt;strong&gt;tl;dr&lt;/strong&gt;: Compared to Earth, the atmosphere on Mars is very thin; in addition, it contains much less of oxygen and water (i.e., is very dry). It is much colder there. These conditions may slow down oxidation to an irrelevant rate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For an object of pure iron, note that according to the English Wikipedia about &lt;a href=&quot;https://en.wikipedia.org/wiki/Mars#Atmosphere&quot; rel=&quot;noreferrer&quot;&gt;Mars&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;The atmosphere of Mars consists of about 96% carbon dioxide, 1.93%&#xA;  argon and 1.89% nitrogen along with traces of oxygen and water.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This contributes as &lt;em&gt;plausible contribution&lt;/em&gt; for a lesser rate of oxidation than on earth because the concentration of an oxidizer (i.e., oxygen) is much lower (0.146 vol%, according to the side table, &lt;em&gt;ibid.&lt;/em&gt;)  if one assumes absence of processes splitting the &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; to yield oxygen.  To set these values into context (entry &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth#Atmosphere&quot; rel=&quot;noreferrer&quot;&gt;Earth&lt;/a&gt;):&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;&quot;A dry atmosphere is composed of 78.084% nitrogen, 20.946% oxygen,&#xA;  0.934% argon, and trace amounts of carbon dioxide and other gaseous molecules. [...] Water vapor content varies between 0.01% and 4% but averages about 1%.&quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Equally note that the reported surface temperatures on Mars (min 130 K, mean 210 K, max 308 K) are substantially lower, than on Earth (min 184 K, mean 287.16 K, max 330 K) -- &lt;em&gt;equally&lt;/em&gt; slowing oxidation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;About water and atmosphere humidity:  Provided the meteorites get water wetted, said perchlorates could start to work as oxidizer of iron.  In comparison to this, &lt;em&gt;dry&lt;/em&gt; perchlorate will remain inactive.  Again, Mars' atmosphere (0.0210 vol% of water vapour, &lt;em&gt;ibid.&lt;/em&gt;) seems to be considerably more conservative than Earth's.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can't have oxidation alone, it is a electrochemical process where some other material in contact with the one oxidized has to be reduced. Corrosion of the meteorites equally could occur if these simultaneously contain grains of metals / alloys differing in the their &lt;a href=&quot;https://en.wikipedia.org/wiki/Standard_electrode_potential&quot; rel=&quot;noreferrer&quot;&gt;electrode potential&lt;/a&gt; provided&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;these grains  were in close contact with each other, especially if their grain boundary were water wetted, &lt;em&gt;and&lt;/em&gt; &lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;if one of the metals / alloys -- relatively speaking -- would be «less noble», i.e. a material with a more negative reduction potential, than any other grain / material in contact.  The less noble grain than would become a &lt;a href=&quot;https://en.wikipedia.org/wiki/Galvanic_anode&quot; rel=&quot;noreferrer&quot;&gt;galvanic anode&lt;/a&gt; and eventually be &quot;eaten away&quot;, protecting the other, more noble one, to be oxidized.(&lt;a href=&quot;http://hyperphysics.phy-astr.gsu.edu/hbase/Tables/electpot.html&quot; rel=&quot;noreferrer&quot;&gt;table&lt;/a&gt;)  The formation of these little, local &lt;a href=&quot;https://en.wikipedia.org/wiki/Electrochemical_cell&quot; rel=&quot;noreferrer&quot;&gt;electrochemical cells&lt;/a&gt; could be even more important if there were &lt;em&gt;salty water&lt;/em&gt; droplets on the surface at room temperature and above accelerating corrosion.  (This, by the way, a reason why steel bridges and copper house roofs exposed to the climate and atmosphere of salty seas are more prone to &lt;a href=&quot;https://en.wikipedia.org/wiki/Galvanic_corrosion&quot; rel=&quot;noreferrer&quot;&gt;galvanic corrosion&lt;/a&gt; than similar constructions only exposed to fresh water.)  Presence of phosphates in said meteorites however could slow down the oxidation of the meteorites (&lt;a href=&quot;https://en.wikipedia.org/wiki/Passivation_(chemistry)&quot; rel=&quot;noreferrer&quot;&gt;passivation&lt;/a&gt;, as assumed for the &lt;a href=&quot;https://en.wikipedia.org/wiki/Iron_pillar_of_Delhi&quot; rel=&quot;noreferrer&quot;&gt;Iron pillar in Dehli&lt;/a&gt;).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Note:&lt;/em&gt; The initial answer assumed iron meteorites to contain discrete grains, occasionally altogether with grains of other metals.  A comment by&lt;code&gt;@KenFabian&lt;/code&gt; pointed out &lt;a href=&quot;https://en.wikipedia.org/wiki/Iron_meteorite&quot; rel=&quot;noreferrer&quot;&gt;iron meteorites&lt;/a&gt; however mainly consist of (Fe,Ni) &lt;em&gt;alloys&lt;/em&gt;.  Their electrochemical properties may be different to their components (e.g, &lt;a href=&quot;https://web.archive.org/web/20150516030826/http://www.corrosionist.com/Galvanic_Series_of_Metal_in_Seawater.htm&quot; rel=&quot;noreferrer&quot;&gt;table&lt;/a&gt;), which the edit aims to include.&lt;/p&gt;&#xA;" OwnerUserId="18990" LastEditorUserId="2470" LastEditDate="2020-03-26T11:58:35.123" LastActivityDate="2020-03-26T11:58:35.123" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="19517" PostTypeId="1" AcceptedAnswerId="19519" CreationDate="2020-03-26T12:20:31.877" Score="1" ViewCount="601" Body="&lt;p&gt;In chapter 13.1 in 'Mesoscale Meteorology in Midlatitudes' (Markowski and Richardson,2011) they use a Bernoulli equation and the hydrostatic equation and a lot of assumptions to derive an equation that predicts the height &lt;span class=&quot;math-container&quot;&gt;$z_{crit}$&lt;/span&gt; at where an air parcel with an initial height of &lt;span class=&quot;math-container&quot;&gt;$z_0$&lt;/span&gt; that is advected towards a barrier loses all horizontal velocity. In their argumentation they state the following identity&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\dfrac{\partial p}{\partial z}(x,z) = \rho(x,z)c_p\theta(x,z)\dfrac{\partial \pi}{\partial z} (x,z)\tag{1}\label{wanted}$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$\pi(x,z)=\left(\frac{p(x,z)}{p_0}\right)^{\frac{R}{c_p}}$&lt;/span&gt; is the Exner function with reference pressure &lt;span class=&quot;math-container&quot;&gt;$p_0\in\mathbb{R}_+$&lt;/span&gt; constant, &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; is pressure, &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; is potential temperature, &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; is density, and &lt;span class=&quot;math-container&quot;&gt;$c_p$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; are constant &lt;span class=&quot;math-container&quot;&gt;$\in \mathbb{R}_+$&lt;/span&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If I try to derive this equation by taking the partial derivative of &lt;span class=&quot;math-container&quot;&gt;$\pi$&lt;/span&gt; with respect to height &lt;span class=&quot;math-container&quot;&gt;$z$&lt;/span&gt; and use the identity &lt;span class=&quot;math-container&quot;&gt;$\pi(x,z)=\frac{T(x,z)}{\theta(x,z)}$&lt;/span&gt; as can be found for example on wikipedia (&lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; is temperature), then I end up with (suppressing arguments &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$z$&lt;/span&gt; in favour of readability)&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\dfrac{\partial \pi}{\partial z} =  \left(\frac{1}{p_0}\right)^{\frac{R}{c_p}}\dfrac{\partial}{\partial z}\exp\left(\frac{R}{c_p}\log(p)\right)=\left(\frac{1}{p_0}\right)^{\frac{R}{c_p}}* \frac{T}{\theta}*{\frac{R}{c_p}}*\frac{1}{p}*\dfrac{\partial p}{\partial z}.$$&lt;/span&gt;&#xA;Multiplying this by &lt;span class=&quot;math-container&quot;&gt;$\rho c_p\theta$&lt;/span&gt; we get &#xA;&lt;span class=&quot;math-container&quot;&gt;$$\rho c_p \theta \dfrac{\partial \pi}{\partial z} = \left(\frac{1}{p_0}\right)^{\frac{R}{c_p}} \frac{T R \rho}{p}*\dfrac{\partial p}{\partial z}$$&lt;/span&gt;&#xA;and because &lt;span class=&quot;math-container&quot;&gt;$\frac{T R \rho}{p}=1$&lt;/span&gt; by the ideal gas law we end up with &#xA;&lt;span class=&quot;math-container&quot;&gt;$$\rho c_p \theta \dfrac{\partial \pi}{\partial z} = \left(\frac{1}{p_0}\right)^{\frac{R}{c_p}}\dfrac{\partial p}{\partial z}.$$&lt;/span&gt;&#xA;This is almost what is stated in &lt;span class=&quot;math-container&quot;&gt;$\eqref{wanted}$&lt;/span&gt;, but not quite and I do not know how to get rid of the factor &lt;span class=&quot;math-container&quot;&gt;$\left(\frac{1}{p_0}\right)^{\frac{R}{c_p}}$&lt;/span&gt; resp. do not see why it remains unmentioned in the textbook. Any help is appreciated.&lt;/p&gt;&#xA;" OwnerUserId="18370" LastEditorUserId="18370" LastEditDate="2020-03-26T12:56:59.270" LastActivityDate="2020-03-30T06:50:42.503" Title="Derivative of Exner function" Tags="|wind|mesoscale-meteorology|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19518" PostTypeId="1" CreationDate="2020-03-26T13:44:16.763" Score="3" ViewCount="101" Body="&lt;p&gt;I'm new to hydrology and I have a question regarding the modeling of multiple reservoirs. I need to estimate the total water inflow to multiple reservoirs that will be observed tomorrow, conditional on the water inflow, temperatures and rainfalls in each reservoir today. What I have in mind is a model similar to&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ TotalInflow_{t} = \beta_0 + \sum_i \beta_i \cdot Inflow_{it-1} + \sum_i \gamma_i \cdot Temperature_{it-1} + \sum_i \phi_i \cdot   Rainfall_{it-1} + \epsilon_t,$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$i$&lt;/span&gt; denotes each single reservoirs, &lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt; denotes time and &lt;span class=&quot;math-container&quot;&gt;$\epsilon_t$&lt;/span&gt; is a random error. Of course, I plan to augment this simple model with lags variables and fixed effects. Importantly, the reservoirs in my data are not connected (e.g., a company owns multiple dams in different rivers). However, looking into the hydrology literature, I could only find paper dealing with a single reservoir rather than the sum of the total inflows across multiple reservoirs (e.g., Coulibalya et al., 2000). What is the common approach in hydrology for this problem (e.g., ARMA models? How many lags? Differencing?)? Do you have a specific reference?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Bibliography:&lt;/strong&gt;&#xA;Coulibaly, Paulin, François Anctil, and Bernard Bobée. &quot;Daily reservoir inflow forecasting using artificial neural networks with stopped training approach.&quot; Journal of Hydrology 230, no. 3-4 (2000): 244-257.&lt;/p&gt;&#xA;" OwnerUserId="19208" LastEditorUserId="19208" LastEditDate="2020-03-27T07:49:48.510" LastActivityDate="2020-03-28T17:19:46.737" Title="Modeling the total water inflow across multiple reservoirs" Tags="|hydrology|rivers|dams|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19519" PostTypeId="2" ParentId="19517" CreationDate="2020-03-26T13:55:31.540" Score="2" Body="&lt;p&gt;Start with the original equation. Let's first write the Hydrostatic equation: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial p}{\partial z}=-\rho g$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So let's prove that &lt;span class=&quot;math-container&quot;&gt;$$-g=c_p\theta\frac{\partial \pi}{\partial z}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we use the product rule, we observe &lt;span class=&quot;math-container&quot;&gt;$$-g=c_p(\frac{\partial \theta \pi}{\partial z}-\pi\frac{\partial \theta}{\partial z})$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since &lt;span class=&quot;math-container&quot;&gt;$\pi=\frac{T}{\theta}$&lt;/span&gt;, we can say that &lt;span class=&quot;math-container&quot;&gt;$T=\pi\theta$&lt;/span&gt;, which makes the above equation&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$-g=c_p(\frac{\partial T}{\partial z}-\pi\frac{\partial \theta}{\partial z})$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It can be shown that&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial \theta}{\partial z}=\frac{\theta}{T}(\frac{\partial T}{\partial z}+\frac{g}{c_p})$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;which can be rewritten as&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial \theta}{\partial z}=\frac{1}{\pi}(\frac{\partial T}{\partial z}+\frac{g}{c_p})$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Substituting this into my fourth equation&#xA;&lt;span class=&quot;math-container&quot;&gt;$$-g=c_p(\frac{\partial T}{\partial z}-\frac{\pi}{\pi}(\frac{\partial T}{\partial z}+\frac{g}{c_p}))$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From here I think you can figure it out. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Derivation for &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial \theta}{\partial z}$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\theta=T(\frac{p_0}{p})^\frac{R_d}{c_p}$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$log(\theta)=log(T)+\frac{R_d}{c_p}(log(p_0)-log(p))$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ \frac{1}{\theta}\frac{\partial \theta}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}-\frac{R_d}{c_p P}\frac{\partial P}{\partial z}$$&lt;/span&gt;&#xA;Utilizing hydrostatic equation&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ \frac{1}{\theta}\frac{\partial \theta}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}+\frac{R_d \rho g}{c_p P}$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ \frac{1}{\theta}\frac{\partial \theta}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}+\frac{g}{c_p T}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ \frac{\partial \theta}{\partial z}=\frac{\theta}{T}(\frac{\partial T}{\partial z}+\frac{g}{c_p })$$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2020-03-26T14:41:37.360" LastActivityDate="2020-03-26T14:41:37.360" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19520" PostTypeId="2" ParentId="19494" CreationDate="2020-03-26T14:38:12.810" Score="7" Body="&lt;p&gt;The carvings are submarine canyons, a part of the continental slope leading from the continental shelf to the continental rise and ultimately the Abyssal plains. They are a product of :&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;erosion through currents and &lt;/li&gt;&#xA;&lt;li&gt;slumping of the continental shelf&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Like other erosive or slumping effects, they can be self-reinforcing, leading to canyon-like structures. The highlighted canyon here is the Gollum Channel system, seen &lt;a href=&quot;https://en.wikipedia.org/wiki/Submarine_canyon#/media/File:Porcupine_Biscay_canyons.png&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="19119" LastActivityDate="2020-03-26T14:38:12.810" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19521" PostTypeId="1" CreationDate="2020-03-26T16:43:14.283" Score="1" ViewCount="51" Body="&lt;p&gt;I am working my way through this paper: &lt;a href=&quot;http://downloads.hindawi.com/journals/amete/2017/8707234.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://downloads.hindawi.com/journals/amete/2017/8707234.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Equations 10 and 11 require the ice water content.  I can't find it in the GFS grib2 file variables.  Did I miss it, or is possible to derive it from the available information.  Right now I have pressure, temperature, and relative humidity.&lt;/p&gt;&#xA;" OwnerUserId="18975" LastActivityDate="2020-03-29T21:19:00.167" Title="Ice Water Content from GFS file" Tags="|meteorology|clouds|weather-forecasting|gfs|cloud-microphysics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19522" PostTypeId="2" ParentId="19513" CreationDate="2020-03-27T18:39:44.197" Score="2" Body="&lt;h1&gt;tl;dr&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;I would suggest considering the borehole measurements as a vertical profile. In terms of the CF Convention it would be a &lt;code&gt;featureType&lt;/code&gt; &lt;a href=&quot;http://cfconventions.org/Data/cf-conventions/cf-conventions-1.8/cf-conventions.html#profile-data&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;code&gt;profile&lt;/code&gt;&lt;/a&gt;, which is described in the &lt;a href=&quot;http://cfconventions.org/Data/cf-conventions/cf-conventions-1.8/cf-conventions.html#discrete-sampling-geometries&quot; rel=&quot;nofollow noreferrer&quot;&gt;discrete sampling geometries section&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I didn't include all reference to the relevant sections in the CF Conventions below. Just comment if import things are missing.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Example netCDF&lt;/h1&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;netcdf borehole_01 {&#xA;dimensions:&#xA;      z = 8 ;&#xA;      profile = 1 ;&#xA;      nv = 2 ;&#xA;&#xA;variables:&#xA;    int profile(profile) ;&#xA;          profile:cf_role = &quot;profile_id&quot;;&#xA;    double time(profile);&#xA;        time:standard_name = &quot;time&quot;;&#xA;        time:long_name = &quot;time&quot; ;&#xA;        time:units = &quot;days since 1970-01-01 00:00:00&quot; ;&#xA;    float lon(profile);&#xA;        lon:standard_name = &quot;longitude&quot;;&#xA;        lon:long_name = &quot;longitude&quot; ;&#xA;        lon:units = &quot;degrees_east&quot; ;&#xA;    float lat(profile);&#xA;        lat:standard_name = &quot;latitude&quot;;&#xA;        lat:long_name = &quot;latitude&quot; ;&#xA;        lat:units = &quot;degrees_north&quot; ;&#xA;    float z(z) ;&#xA;        z:standard_name = &quot;depth&quot;;&#xA;        z:long_name = &quot;depth below ...&quot; ;&#xA;        z:units = &quot;m&quot; ;&#xA;        z:positive = &quot;down&quot; ;&#xA;        z:axis = &quot;Z&quot; ;&#xA;        z:bounds = &quot;z_bnds&quot; ;&#xA;    float z_bnds(z, nv) ;&#xA;    float temp(profile, z) ;&#xA;        temp:standard_name = &quot;soil_temperature&quot; ;&#xA;        temp:long_name = &quot;soil_temperature&quot; ;&#xA;        temp:units = &quot;K&quot; ;&#xA;        temp:coordinates = &quot;time lon lat z&quot; ;&#xA;        temp:cell_methods = &quot;z: mean&quot; ;&#xA;&#xA;// global attributes:&#xA;        :featureType = &quot;profile&quot;;&#xA;&#xA;data:&#xA;&#xA; z = 5, 15, 25, 45, 55, 70, 90, 150 ;&#xA;&#xA; z_bnds = &#xA;  0, 10,&#xA;  10, 20,&#xA;  20, 30,&#xA;  40, 50,&#xA;  50, 60, &#xA;  60, 80,&#xA;  80, 100,&#xA;  100, 200 ;&#xA;&#xA; temp = 279.4, 278.8, 278.3, 277.0, 277.1, 276.9, 277.0, 279.2 ;&#xA;}&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;h1&gt;Explanation&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;The variable &lt;code&gt;temp&lt;/code&gt; is an example for a data variable in the file.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Basic depth information&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Please see CF Conventions section &lt;a href=&quot;http://cfconventions.org/Data/cf-conventions/cf-conventions-1.8/cf-conventions.html#cell-boundaries&quot; rel=&quot;nofollow noreferrer&quot;&gt;7.1 Cell Boundaries&lt;/a&gt; for details&lt;/em&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;code&gt;z_bnds&lt;/code&gt; provides the boundaries of intervals over which the temperature is averaged. The attribute &lt;code&gt;bounds&lt;/code&gt; of variable &lt;code&gt;z&lt;/code&gt; points to these boundary data. In this example, I wrote the average depth of each interval into the &lt;code&gt;z&lt;/code&gt; variable. However, this is no requirement (as far as I know). It might be also the upper or lower depth of each interval or another depth in between. &lt;code&gt;z_bnds&lt;/code&gt; automatically inherits all relevant attributs from &lt;code&gt;z&lt;/code&gt;. Therefore, it has no own &lt;code&gt;units&lt;/code&gt; and &lt;code&gt;standard_name&lt;/code&gt; attributes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;As you can see in the data for &lt;code&gt;z_bnds&lt;/code&gt; (or in the table below), it is possible to skip depth ranges (between depth invertal 3 and 4) and to have differently spaced intervals (e.g. interval 6 compared to previous intervals).&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;| **depth interval** | **minimum** | **maximum** |&#xA;|--------------------|-------------|-------------|&#xA;| 1                  | 0           | 10          |&#xA;| 2                  | 10          | 20          |&#xA;| 3                  | 20          | *30*        |&#xA;| 4                  | *40*        | 50          |&#xA;| 5                  | 50          | 60          |&#xA;| 6                  | *60*        | *80*        |&#xA;| 7                  | 80          | 100         |&#xA;| 8                  | 100         | 200         |&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;h2&gt;Connecting data variables proberly to the vertical coordinate&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Please see CF Conventions section &lt;a href=&quot;http://cfconventions.org/Data/cf-conventions/cf-conventions-1.8/cf-conventions.html#cell-methods&quot; rel=&quot;nofollow noreferrer&quot;&gt;7.3 Cell Methods&lt;/a&gt; for details on the first paragraph and section &lt;a href=&quot;http://cfconventions.org/Data/cf-conventions/cf-conventions-1.8/cf-conventions.html#_two_dimensional_latitude_longitude_coordinate_variables&quot; rel=&quot;nofollow noreferrer&quot;&gt;5.2 Two-Dimensional Latitude, Longitude, Coordinate Variables&lt;/a&gt; for details on the second paragraph.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The value &lt;code&gt;z: mean&lt;/code&gt; of the attribute &lt;code&gt;cell_methods&lt;/code&gt; of variable &lt;code&gt;temp&lt;/code&gt; tells us that the temperature is an average value in z-direction over the interval provided in &lt;code&gt;z_bnds&lt;/code&gt;. The latter (&lt;em&gt;over the interval provided in &lt;code&gt;z_bnds&lt;/code&gt;&lt;/em&gt;) is implicitely assumed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The value &lt;code&gt;time lon lat z&lt;/code&gt; of the &lt;code&gt;coordinates&lt;/code&gt; attribute of variable &lt;code&gt;temp&lt;/code&gt; indicates that the variables &lt;code&gt;time&lt;/code&gt;, &lt;code&gt;lon&lt;/code&gt;, &lt;code&gt;lat&lt;/code&gt; and &lt;code&gt;z&lt;/code&gt; provided temporal and spatial dimensions to each value of &lt;code&gt;temp&lt;/code&gt;. Really proper software should be able to map each value of &lt;code&gt;temp&lt;/code&gt; a the correspondinc &lt;code&gt;time&lt;/code&gt;, &lt;code&gt;lat&lt;/code&gt; and &lt;code&gt;lon&lt;/code&gt; values via the dimension &lt;code&gt;profile&lt;/code&gt;. However, implementing this properly is hard work. Therefore, most software package won't recognize it or might even have issues with it. I your software package throws errors, one first step should be to remove the attribute &lt;code&gt;coordinates&lt;/code&gt;.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Setting global attributes&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Please see CF Conventions section &lt;a href=&quot;http://cfconventions.org/Data/cf-conventions/cf-conventions-1.8/cf-conventions.html#_features_and_feature_types&quot; rel=&quot;nofollow noreferrer&quot;&gt;Features and feature types&lt;/a&gt; for details&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The global attribute &lt;code&gt;featureType&lt;/code&gt; is mandatory when we have a discret sampling geometry.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;Several boreholes with different depth intervals&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;For details on &lt;code&gt;coordinate variables&lt;/code&gt; and &lt;code&gt;auxiliary coordinate variables&lt;/code&gt; please have a look into sections &lt;a href=&quot;http://cfconventions.org/Data/cf-conventions/cf-conventions-1.8/cf-conventions.html#terminology&quot; rel=&quot;nofollow noreferrer&quot;&gt;1.2 Terminology&lt;/a&gt; and &lt;a href=&quot;http://cfconventions.org/Data/cf-conventions/cf-conventions-1.8/cf-conventions.html#coordinate-system&quot; rel=&quot;nofollow noreferrer&quot;&gt;5 Coordinate System&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Via the dimension &lt;code&gt;profile&lt;/code&gt; we could save several boreholes in one file. In the current situation, the samplings depths of each borehole would be the same. One could make the variable &lt;code&gt;z&lt;/code&gt; and &lt;code&gt;z_bnds&lt;/code&gt; dependent on &lt;code&gt;profile&lt;/code&gt; to provide depth intervals for each borehole. However, then we needed to rename the variables &lt;code&gt;z&lt;/code&gt; and &lt;code&gt;z_bnds&lt;/code&gt; because a variable might only have the same name of a dimension, if the variable is onedimensional and only depends on this dimension (a &lt;code&gt;coordiante variable&lt;/code&gt;). When a variable like the depth depends on two dimensions, it becomes and auxiliary coordinate variable and has to have a different names. Thus, we would have &lt;code&gt;double depth(profile, z)&lt;/code&gt; instead of &lt;code&gt;z(z)&lt;/code&gt; and &lt;code&gt;double depth_bnds(profile, z, nv)&lt;/code&gt; instead of &lt;code&gt;z_bnds(z, nv)&lt;/code&gt;. The &lt;code&gt;temp:coordiantes&lt;/code&gt; would have a value of &lt;code&gt;time lat lon depth&lt;/code&gt; (because &lt;code&gt;depth&lt;/code&gt; is the vertical coordinates) but &lt;code&gt;temp:cell_methods&lt;/code&gt; would remain &lt;code&gt;z: mean&lt;/code&gt; (because we calculate average in z-direction).&lt;/p&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2020-03-27T18:39:44.197" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19523" PostTypeId="1" AcceptedAnswerId="20229" CreationDate="2020-03-28T10:10:03.363" Score="3" ViewCount="382" Body="&lt;p&gt;There is much known about Earth's core from painstaking analysis of seismic data, and from detailed magnetic field maps and trends over time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any other measurements that have contributed to current understanding of Earth's core besides these two?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2020-09-20T23:23:07.020" Title="Do we know anything about the nature of Earth's core that hasn't come from magnetic or seismic measurements?" Tags="|seismology|planetary-science|geomagnetism|core|" AnswerCount="4" CommentCount="15" ContentLicense="CC BY-SA 4.0" />
  <row Id="19524" PostTypeId="2" ParentId="19517" CreationDate="2020-03-28T16:46:11.040" Score="0" Body="&lt;p&gt;The mistake is hidden in the identity &lt;span class=&quot;math-container&quot;&gt;${\partial \over \partial z} \log (p) = {1\over p} {\partial p \over \partial z}$&lt;/span&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This formula looks harmless and would be correct if &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; was a real valued function of &lt;span class=&quot;math-container&quot;&gt;$z$&lt;/span&gt;, but &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; is actually a pressure value and so &lt;span class=&quot;math-container&quot;&gt;$\log(p)$&lt;/span&gt; is undefined. Instead, let &lt;span class=&quot;math-container&quot;&gt;$p^*=p/p_0$&lt;/span&gt; be a non-dimensional pressure, and then:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;{\partial \over \partial z} \log(p^*) = {1\over p^*} {\partial p^*\over \partial z} = {1\over p} {\partial p\over \partial z}.&#xA;$$&lt;/span&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Put this in your derivation and the spurious &lt;span class=&quot;math-container&quot;&gt;$\left( 1 \over p_0 \right)^{R\over c_p}$&lt;/span&gt; will disappear.&lt;/p&gt;&#xA;" OwnerUserId="17518" LastActivityDate="2020-03-28T16:46:11.040" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19525" PostTypeId="2" ParentId="19523" CreationDate="2020-03-28T21:49:26.980" Score="4" Body="&lt;p&gt;Short answer: yes, most of our knowledge is not from seismics and geomagnetism, but from experiment and measurements, deductions from geochemistry and -physics, material science and physics in general (besides the already mentioned measurements of earth's gravity, but the variations are rather connected to mantle convection, water storage, etc. than the core). But all in all those weigh much more than &quot;painstaking&quot; seismics and geomagnetism.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One experiment to replicate pressure/temperature (p/t) conditions is the diamond anvil cell and its cascaded version in combination with laser heating of the probe, to obtain data about mineral and cristalline phases and transitions under conditions in a planet's core.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Wikipedia: &lt;a href=&quot;https://en.wikipedia.org/wiki/Diamond_anvil_cell&quot; rel=&quot;nofollow noreferrer&quot;&gt;Diamond Anvil Cell&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Teaching Mineralogy; Topical Resources &lt;a href=&quot;https://serc.carleton.edu/NAGTWorkshops/mineralogy/mineral_physics/diamond_anvil.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Diamond Anvil Cell (DAC)&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;And some random links on the outcome of the matter:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Reviews of Geophyics: &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/1998RG000053&quot; rel=&quot;nofollow noreferrer&quot;&gt;High-Pressure Experiments and the Phase Diagram of Lower Mantle and Core Materials&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Nature Communications: &lt;a href=&quot;https://www.nature.com/articles/ncomms2160&quot; rel=&quot;nofollow noreferrer&quot;&gt;Implementation of micro-ball nanodiamond anvils for high-pressure studies above 6 Mbar&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Earth and Planetary Science Letters: &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0012821X13002355&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Earth's core composition from high pressure density measurements of liquid iron alloys&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Geophysical Research Letters: &lt;a href=&quot;https://ui.adsabs.harvard.edu/abs/2002GeoRL..29.1471L/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iron-Nickel alloy in the Earth's core&lt;/a&gt;&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Laser pulses is a developing technique to reach very high p/t conditions, higher than diamond anvil cells can, but they do not last that long&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Science Advances: &lt;a href=&quot;https://advances.sciencemag.org/content/4/4/eaao5864&quot; rel=&quot;nofollow noreferrer&quot;&gt;Crystal structure and equation of state of Fe-Si alloys at super-Earth core conditions&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-03-29T16:18:53.490" LastActivityDate="2020-03-29T16:18:53.490" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19527" PostTypeId="1" CreationDate="2020-03-29T14:14:06.533" Score="3" ViewCount="46" Body="&lt;p&gt;I have a hydrodynamic model to simulate flash floods. This model expects roughness data in the Strickler coefficient format (kst) in the unit m&lt;sup&gt;1/3&lt;/sup&gt; per second.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I got a table with roughness values I'm supposed to use. However the values in the table are in the format mm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I checked for kst tables online but found different values for the same surface or value ranges like 10 - 15 or highly specific values like &quot;high grass, low grass, pasture&quot;. But in the table I got there is just one value for 'grass'. Thus, I would like to use the table I got. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is, how do I transfer the roughness values from mm to m&lt;sup&gt;1/3&lt;/sup&gt; per second?  &lt;/p&gt;&#xA;" OwnerUserId="18169" LastEditorUserId="2470" LastEditDate="2020-03-29T17:28:30.247" LastActivityDate="2020-03-29T17:28:30.247" Title="How to transfer surface roughness from the unit mm into Strickler coefficient m1/3 per second" Tags="|hydrology|models|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19528" PostTypeId="2" ParentId="19521" CreationDate="2020-03-29T21:19:00.167" Score="1" Body="&lt;p&gt;There is a parameter &lt;code&gt;ice water mixing ratio&lt;/code&gt; in the &lt;code&gt;gfs.t&amp;lt;hour&amp;gt;z.pgrb2.0p25.f&amp;lt;step&amp;gt;&lt;/code&gt; file given at isobaric levels. &lt;/p&gt;&#xA;" OwnerUserId="3385" LastActivityDate="2020-03-29T21:19:00.167" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19530" PostTypeId="2" ParentId="19517" CreationDate="2020-03-30T06:50:42.503" Score="1" Body="&lt;p&gt;After looking back into this I found my error to lie in the long equation &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\dfrac{\partial \pi}{\partial z}=\left(\frac{1}{p_0}\right)^{\frac{R}{c_p}}\dfrac{\partial}{\partial z}\exp\left(\frac{R}{c_p}\log(p)\right)=\left(\frac{1}{p_0}\right)^{\frac{R}{c_p}}* \frac{T}{\theta}*{\frac{R}{c_p}}*\frac{1}{p}*\dfrac{\partial p}{\partial z}$&lt;/span&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was wrong, because &lt;span class=&quot;math-container&quot;&gt;$$\dfrac{\partial}{\partial z}\exp\left(\frac{R}{c_p}\log(p)\right)\neq \frac{T}{\theta}*{\frac{R}{c_p}}*\frac{1}{p}*\dfrac{\partial p}{\partial z},$$&lt;/span&gt; but rather &lt;span class=&quot;math-container&quot;&gt;$$\dfrac{\partial}{\partial z}\exp\left(\frac{R}{c_p}\log(p)\right) =\left(p\right)^{\frac{R}{c_p}}*{\frac{R}{c_p}}*\frac{1}{p}*\dfrac{\partial p}{\partial z}.$$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="18370" LastActivityDate="2020-03-30T06:50:42.503" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19531" PostTypeId="2" ParentId="19107" CreationDate="2020-03-30T09:54:57.047" Score="5" Body="&lt;p&gt;These are transform faults that result from differential spreading rates of the middle ocean ridge. As such they are part of the plate boundary. Possible causes are different production rates of magma, thermal differences of the sea floor, differences of relative plate movement.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Transform_fault&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Transform_fault&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Mid-ocean_ridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Mid-ocean_ridge&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Paywalled:&#xA;&lt;a href=&quot;https://science.sciencemag.org/content/329/5995/1047.full&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dynamical Instability Produces Transform Faults at Mid-Ocean Ridges&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And:&#xA;Wilson, 1965: &lt;a href=&quot;https://www.nature.com/articles/207343a0&quot; rel=&quot;nofollow noreferrer&quot;&gt;A New Class of Faults and their Bearing on Continental Drift&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Inactive transform faults extending beyond the spreading zone are sometimes generally named &quot;fracture zone&quot;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But transform faults can also reach all the way to the next subduction zone (e.g. Azores-Gibraltar fault zone) and be responsible for devastating &lt;a href=&quot;https://en.wikipedia.org/wiki/1755_Lisbon_earthquake&quot; rel=&quot;nofollow noreferrer&quot;&gt;earthquakes&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-03-30T18:17:43.890" LastActivityDate="2020-03-30T18:17:43.890" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="19532" PostTypeId="1" CreationDate="2020-03-30T18:28:27.307" Score="6" ViewCount="165" Body="&lt;p&gt;new student of Oceanography here! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm studying Earth Science right now, and I found conflicting reporting re: the formation of the Grand Canyon; whether it was formed singularly by the Colorado River over millions of years, or if it was formed by other processes with the river only filling into it relatively recently. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a consensus yet in geology with regard to the Grand Canyon's geologic history? If so, could you share resources that help explain it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thank you so much!&lt;/p&gt;&#xA;" OwnerUserId="20221" LastEditorDisplayName="user20559" LastEditDate="2021-03-25T15:36:46.673" LastActivityDate="2021-03-26T06:50:02.463" Title="Has a scientific consensus been reached concerning the formation of the Grand Canyon?" Tags="|geology|earth-history|rivers|stratigraphy|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19533" PostTypeId="1" CreationDate="2020-03-31T05:33:19.100" Score="1" ViewCount="867" Body="&lt;p&gt;I'm trying to create figures in MatLab and am a reasonably new user, I'm wondering if there is a good way to make plots that use a common x-axis and then vertically stacked and alternating y-axes as in the picture below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So far I have been using the subplot function and it's not really doing the trick for me.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/x9z4z.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/x9z4z.png&quot; alt=&quot;Example plot&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20223" LastActivityDate="2020-03-31T05:33:19.100" Title="MATLAB - How to plot multiple timeseries (paleoclimate) with a common x axis and multiple stacked y axes?" Tags="|geochemistry|matlab|paleoclimate|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19534" PostTypeId="1" CreationDate="2020-03-31T12:50:54.457" Score="1" ViewCount="235" Body="&lt;p&gt;I need to plot bathymetry map of my study region and need to convert the .srtm to .xyz or .grd format to use GMT. I tried to do this with grdraster and xyz2grd, but got wrong results. I found that there is srtm2grd command in Linux but I do not have it in my commands. the data are in the following address: &lt;a href=&quot;ftp://topex.ucsd.edu/pub/srtm30_plus/srtm30/data/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ftp://topex.ucsd.edu/pub/srtm30_plus/srtm30/data/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20228" LastActivityDate="2020-04-05T07:25:39.350" Title="convert .srtm to xyz ord grd" Tags="|mapping|gis|" AnswerCount="3" CommentCount="7" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19536" PostTypeId="2" ParentId="19262" CreationDate="2020-04-01T06:38:14.037" Score="-4" Body="&lt;p&gt;Starting from the beginning, the universe started with an explosion which generated, as the initial plasma cooled, mainly hydrogen and helium (&lt;a href=&quot;https://bbanglm.weebly.com/hydrogen-and-helium.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;The creation of hydrogen and helium&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The heavier elements such as carbon and oxygen were created later, as the first generation of stars collapsed and exploded in supernovae. It is thought that our Sun is a 3rd generation star (see &quot;&lt;a href=&quot;https://www.physlink.com/Education/AskExperts/ae465.cfm&quot; rel=&quot;nofollow noreferrer&quot;&gt;What is meant by the theory that the sun is a third generation star?&lt;/a&gt;&quot;). Hence, we can say that the presence of carbon and oxygen in the solar system is caused by the stellar explosions which came before the formation of our Sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When the planets formed around the Sun, carbon and oxygen were part of the mix of elements that came together. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The processes leading to the formation of the early atmosphere, before life started on Earth are unclear, though it is certain that there were frequent meteor impacts and volcanic eruptions in this period (because the solar system was much more crowded and the Earth's core was much hotter -- see for example &lt;a href=&quot;https://www.iflscience.com/space/earth-s-primordial-atmosphere-lost-due-relentless-small-impacts/&quot; rel=&quot;nofollow noreferrer&quot;&gt;IFL Science&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we look at nearby planets, we see that Mars has an atmosphere of 95% carbon dioxide, and Venus has 96%. On Earth it makes up only 0.04% of our atmosphere (&lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atmosphere of the Earth&lt;/a&gt;). The difference is due to life on Earth, which has taken CO2 out of the atmosphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Coal deposits were laid down in the Carboniferous, as stated in the question. At the time, atmospheric CO2 was at much higher concentrations, so the growth may have been denser, which could (I don't have a reference for this) have contributed to the fact that material got buried before it could rot (see &quot;&lt;a href=&quot;https://forces.si.edu/atmosphere/02_02_06.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Age of Oxygen&lt;/a&gt;&quot; for some discussion).&lt;/p&gt;&#xA;" OwnerUserId="17518" LastActivityDate="2020-04-01T06:38:14.037" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19538" PostTypeId="2" ParentId="19262" CreationDate="2020-04-01T11:59:21.827" Score="1" Body="&lt;p&gt;&lt;a href=&quot;https://www.bbc.co.uk/bitesize/guides/zt6g87h/revision/4&quot; rel=&quot;nofollow noreferrer&quot;&gt;Prior to the carboniferous period&lt;/a&gt;, and until the human industrial era, the &lt;a href=&quot;https://sciencing.com/earths-first-atmosphere-contained-gases-2034.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;majority of carbon dioxide&lt;/a&gt; in the &lt;a href=&quot;http://volcano.oregonstate.edu/origin-atmosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;atmosphere&lt;/a&gt; was &lt;a href=&quot;https://www.forbes.com/sites/startswithabang/2017/06/06/how-much-co2-does-a-single-volcano-emit/#3a3d71195cbf&quot; rel=&quot;nofollow noreferrer&quot;&gt;due to volcanoes&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;For billions of years, geological processes like volcanic eruptions controlled the carbon concentration in the atmosphere, as volcanism is the major way that carbon rises from the mantle into the atmosphere. Most of the carbon stored in the mantle is in the form of carbonate (a salt of carbonic acid), but there are also huge stores of actual carbon dioxide sequestered deep within the mantle as a dissolved gas within the liquid rock. &lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;We can measure the degassing of Mt. Etna extremely well, and find that it adds about 16,000 tons of CO2 to the atmosphere each day, or 5.8 million tons per year. This might not sound impressive, but it's only one volcano. Interestingly, it's not just smoking, actively erupting volcanoes that emit CO2, but seemingly inactive volcanoes around arcs and rift zones. Persistent degassing still occurs around a great number of volcanoes worldwide, on a continuous basis.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-04-01T11:59:21.827" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19539" PostTypeId="2" ParentId="19534" CreationDate="2020-04-01T14:57:31.193" Score="3" Body="&lt;p&gt;&lt;strong&gt;NOTE:&lt;/strong&gt; &lt;em&gt;This is not the solution to the question in the title &lt;strong&gt;but it solves the problem described in the question's text&lt;/strong&gt;.&lt;/em&gt;&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Alternative solution&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;I would download the &lt;code&gt;netCDF&lt;/code&gt; files from the &lt;code&gt;grd&lt;/code&gt; directory instead of the &lt;code&gt;srtm&lt;/code&gt; files from the &lt;code&gt;data&lt;/code&gt; directory on the FTP server. The &lt;code&gt;netCDF&lt;/code&gt; files can directly be plotted by GMT.&lt;/p&gt;&#xA;&#xA;&lt;h1&gt;Example&lt;/h1&gt;&#xA;&#xA;&lt;p&gt;Based on this file: &lt;a href=&quot;ftp://topex.ucsd.edu/pub/srtm30_plus/srtm30/grd/e020n40.nc&quot; rel=&quot;nofollow noreferrer&quot;&gt;e020n40.nc&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;#!/bin/bash&#xA;&#xA;outfile=pic.ps&#xA;infile=e020n40.nc&#xA;invar=z&#xA;colorfile=colors.cpt&#xA;&#xA;gmt makecpt -Cviridis -D -T-5200/2400/400 &amp;gt; ${colorfile}&#xA;&#xA;gmt psbasemap -R20/60/-10/40 -JM18 -B4/4&quot;NSEW&quot; -X+1.5c -P -K &amp;gt; &lt;span class=&quot;math-container&quot;&gt;${outfile}&#xA;gmt grdimage $&lt;/span&gt;{infile}?&lt;span class=&quot;math-container&quot;&gt;${invar} -R -J -C$&lt;/span&gt;{colorfile} -O -K &amp;gt;&amp;gt; &lt;span class=&quot;math-container&quot;&gt;${outfile}&#xA;gmt pscoast -J -R -Di -W1,black -O &amp;gt;&amp;gt; $&lt;/span&gt;{outfile}&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;output (&lt;code&gt;pic.ps&lt;/code&gt; imported into GIMP v2.8.22 in 60 dpi resolution and with strong antialiasing):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/L894w.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/L894w.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5594" LastActivityDate="2020-04-01T14:57:31.193" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19540" PostTypeId="1" AcceptedAnswerId="19541" CreationDate="2020-04-01T17:11:29.467" Score="1" ViewCount="229" Body="&lt;p&gt;The NCEP website describes the file naming format of the GFS forecast data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nco.ncep.noaa.gov/pmb/products/gfs/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nco.ncep.noaa.gov/pmb/products/gfs/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What does &quot;forecast hour of product&quot; mean? &lt;/p&gt;&#xA;" OwnerUserId="18975" LastActivityDate="2020-04-01T18:16:01.190" Title="What is the &quot;forecast hour of product&quot;" Tags="|meteorology|weather-forecasting|gfs|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19541" PostTypeId="2" ParentId="19540" CreationDate="2020-04-01T18:16:01.190" Score="3" Body="&lt;p&gt;The forecast hour of the product is the hour after the model cycle runtime that the forecast is valid at. For example, if the the cycle runtime is 12Z and the forecast hour is 9, then the the forecast is valid for 21Z. If the cycle runtime is 6Z and the forecast hour is 48, then the forecast is valid at 6Z two days later. &lt;/p&gt;&#xA;" OwnerUserId="11269" LastActivityDate="2020-04-01T18:16:01.190" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19542" PostTypeId="1" CreationDate="2020-04-01T19:41:33.857" Score="1" ViewCount="1955" Body="&lt;p&gt;I have a 2d xarray dataset and I am having several nan values in the dataset. These nan values need to be filled with the nearest non-nan values in the 2d array. How do I do this? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am trying to make my data consistent with the grid_spec file that the earth system model reads. And there are inconsistencies on what the land points are in the forcing data and grid_spec file leading to the blowing up of model.&lt;/p&gt;&#xA;" OwnerUserId="18076" LastActivityDate="2020-04-05T06:51:03.663" Title="How to search for the nearest non nan value in 2d xarray dataset" Tags="|meteorology|atmosphere-modelling|atmospheric-circulation|python|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19543" PostTypeId="2" ParentId="19250" CreationDate="2020-04-01T21:19:50.153" Score="1" Body="&lt;p&gt;I think you are confusing eddy diffusivity with molecular diffusivity. Whereas the latter increases with temperature, for the former there is no such relationship. Eddy diffusivity describes momentum transport due to eddies. The strength of the eddy diffusivity increases with decreasing buoyancy frequency, which is the case, when moving from the bottom of the mixed layer further downwards in the ocean. &lt;/p&gt;&#xA;" OwnerUserId="13524" LastActivityDate="2020-04-01T21:19:50.153" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19544" PostTypeId="2" ParentId="19542" CreationDate="2020-04-02T09:51:41.897" Score="2" Body="&lt;p&gt;If I were you, I would exclude the NaN values and then perform gridding on the resulting irregularly spaced data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are already the tools to perform this in Python and using the library SciPy&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://scipy-cookbook.readthedocs.io/items/Matplotlib_Gridding_irregularly_spaced_data.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://scipy-cookbook.readthedocs.io/items/Matplotlib_Gridding_irregularly_spaced_data.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But please document exactly what step you are doing and why. Excluding data is always ... interpreting the data.&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2020-04-02T09:51:41.897" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19545" PostTypeId="2" ParentId="17915" CreationDate="2020-04-02T13:24:13.867" Score="2" Body="&lt;p&gt;Up to now, we constrained the (relative) plate movements mostly with seismic slip measurments. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since 10-20 years, with the diffusion of GPS measurments, it has been possible to have a more granular distribution of movements and a more precise estimation of the rotation pole for a given plate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Roughly speaking, then, you should look for the work of authors like these:&#xA;&lt;a href=&quot;https://meetingorganizer.copernicus.org/EGU2017/EGU2017-14816-1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://meetingorganizer.copernicus.org/EGU2017/EGU2017-14816-1.pdf&lt;/a&gt; (just a random &quot;scientific&quot; google result for the search)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The end product (an accurate determination of rotation poles) should help in estabilishing the seismic hazard, by observing gaps and differential displacements, possibly representing loading of the fault, in a very primitive Reid (1910) way of thinking:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wGPB0.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wGPB0.gif&quot; alt=&quot;https://earthquake.usgs.gov/earthquakes/events/1906calif/18april/reid.php USGS image &quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/events/1906calif/18april/images/ElasticRebound.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earthquake.usgs.gov/earthquakes/events/1906calif/18april/images/ElasticRebound.gif&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have no right on the image, it comes from the USGS site.&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2020-04-02T13:24:13.867" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19546" PostTypeId="2" ParentId="19523" CreationDate="2020-04-03T00:28:41.517" Score="1" Body="&lt;p&gt;The comments to the other question have already alluded to some physical answers that also come out of the lab: One might think that the heaviest elements in primordial Earth should have all sunk into the core by now. But that's not actually the case: For example, uranium with a density 2.5 times that of iron (19.1 vs 7.9 g/cm&lt;sup&gt;3&lt;/sup&gt;) has an abundance of about 4 ppm in the mantle, whereas in the core its abundance &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4798/what-percent-of-the-earths-core-is-uranium&quot;&gt;is believed to be essentially zero&lt;/a&gt;. How do we know this? We can make experiments about how easily uranium dissolves in rocky materials vs in iron melts -- and it turns out that if it has a choice, uranium very much prefers to associate itself with rocks and not with iron.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastEditorUserId="2470" LastEditDate="2020-04-03T04:03:20.273" LastActivityDate="2020-04-03T04:03:20.273" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19548" PostTypeId="1" CreationDate="2020-04-03T09:12:38.187" Score="11" ViewCount="676" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;The World Meteorological Organization (WMO) is concerned about the impact of the COVID-19 pandemic on the quantity and quality of weather observations and forecasts, as well as atmospheric and climate monitoring.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://public.wmo.int/en/media/press-release/wmo-concerned-about-impact-of-covid-19-observing-system&quot; rel=&quot;noreferrer&quot;&gt;https://public.wmo.int/en/media/press-release/wmo-concerned-about-impact-of-covid-19-observing-system&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apparently, meteorological data sent by aircrafts play a big role in establishing weather forecasts. Due to SARS-CoV-2, fewer airplanes than usual are up in the sky, therefore less data is available.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The chart on that page shows a significant decrease in AMDAR data, however, is there any data available on how much this actually increases the prediction error of weather forecasts?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a project that tracks and publishes data regarding weather prediction errors on a regular basis that would help with analyzing the correlation between incoming data and prediction error?&lt;/p&gt;&#xA;" OwnerUserId="20240" LastActivityDate="2020-04-06T07:09:51.090" Title="How much does COVID-19 affect weather forecasts?" Tags="|meteorology|measurements|statistics|weatherdata|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19549" PostTypeId="2" ParentId="19548" CreationDate="2020-04-03T12:45:52.687" Score="3" Body="&lt;p&gt;Welcome to Earth Science SE! &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given that the crisis is still ongoing, I doubt we know the full extent of the impact (forecasting the weather is hard enough, forecasting the impact of a pandemic is outside my expertise). But, at least one conference  was supposed t&#xA;o go to was cancelled. And I know the lack of airplane obs is impacting data assimilation. Beyond that, I am not sure. Some hypotheses perhaps include:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Is the change in the quality of life may be impacting forecaster accuracy?&lt;/li&gt;&#xA;&lt;li&gt;What impact does the delay in communication of scientific research have on forecast accuracy?&lt;/li&gt;&#xA;&lt;li&gt;How does this impact the future science budget?&lt;/li&gt;&#xA;&lt;li&gt;How does the absence of airplane data degrade forecasts (could be evaluated using a &lt;a href=&quot;https://gmao.gsfc.nasa.gov/observing_sys_science/OSSE/&quot; rel=&quot;nofollow noreferrer&quot;&gt;OSSE experiment&lt;/a&gt;)? On a related note, how &lt;/li&gt;&#xA;&lt;li&gt;How is the communication of weather forecasts by in-studio meteorologists compare to meteorologists that are in self-quarantine?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;How this ordeal has affected weather forecasts may be a good cross-disciplinary study for the future.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To fully answer your question, you can look at &lt;a href=&quot;https://journals.ametsoc.org/doi/full/10.1175/2009MWR3097.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Benjamin et al. (2006)&lt;/a&gt; to evaluate the relative impacts of different observational systems. Certainly there have been some changes since then, but this can give a cursory idea of what we might be looking at.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2020-04-03T12:51:57.383" LastActivityDate="2020-04-03T12:51:57.383" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19550" PostTypeId="1" CreationDate="2020-04-04T02:33:05.407" Score="1" ViewCount="941" Body="&lt;p&gt;Wikipedia's &lt;a href=&quot;https://en.wikipedia.org/wiki/Seismic_wave&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seismic wave&lt;/a&gt; includes the plot below of the speed of S and P waves as a function of depth in the Earth. In the region of the outer core the speed of S-waves or shear waves is shown to be zero but really they are evanescent and so the velocity is probably complex.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then at the inner core boundary the speed of S-waves is shown again down to the center of the Earth, fairly flat near 4 km/sec.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the speed of shear waves in the Earth's inner core a &lt;em&gt;measured quantity&lt;/em&gt; or is this just deduced? If it's measured, how do these shear waves get to the core if they can not propagate through the outer core? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FWhdB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FWhdB.png&quot; alt=&quot;Speeds of seismic waves.PNG&quot;&gt;&lt;/a&gt; &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Speeds_of_seismic_waves.PNG&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2020-04-04T08:51:05.330" Title="How do we know the speed of S-waves (shear waves) in the Earth's inner core? Has this been measured?" Tags="|seismology|measurements|seismic|core|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19551" PostTypeId="1" CreationDate="2020-04-04T03:58:43.070" Score="1" ViewCount="151" Body="&lt;p&gt;Danube is 2850 km long and yet Rhine (1233 km) is considered the longest River in Germany.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Likewise,the confusion between Yenisei and Volga in Russia.&lt;/p&gt;&#xA;" OwnerUserId="20246" LastActivityDate="2020-04-04T03:58:43.070" Title="Which is the longest River in Germany and Russia?" Tags="|geography|rivers|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19552" PostTypeId="2" ParentId="19550" CreationDate="2020-04-04T07:05:11.510" Score="3" Body="&lt;p&gt;If waves would travel only &lt;em&gt;through&lt;/em&gt; a medium while keeping their form (i.e., P-waves remain P-waves and S-waves remain S-waves), you would obtain something a bit like this video: &lt;a href=&quot;https://www.youtube.com/watch?v=YctV5crEXyM&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=YctV5crEXyM&lt;/a&gt; . &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, standard models for wave propagation are more complicated than that. Upon hitting an interface, P-waves both &lt;em&gt;reflect off&lt;/em&gt; and &lt;em&gt;refract into&lt;/em&gt; the other material. And if this happens at a bit of an angle, it even generates a &lt;em&gt;reflected&lt;/em&gt; and a &lt;em&gt;refracted&lt;/em&gt; S-wave (if the material allows it!). Something like this image:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tvgsRm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tvgsRm.jpg&quot; alt=&quot;P-S wave interface plot&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What you see is a P-wave that comes towards an interface between two different media (Vp=P-wave velocity, Vs=S-wave velocity, \rho=density). After hitting the interface, it creates 4 new waves! Two P-waves, two S-waves. A similar figure can be made for an S-wave hitting an interface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So we can follow a hypothetical wave-path as follows:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;There is a P-wave generated at the Earth's surface that travels down from the crust to the mantle (creating 4 new wave modes as in the figure above; &lt;strong&gt;we follow the transmitted P-wave that goes down&lt;/strong&gt;), &lt;/li&gt;&#xA;&lt;li&gt;That wavefront travels from the mantle to the outer core (which creates 3 wave modes because there is no &lt;em&gt;transmitted&lt;/em&gt; S-wave! &lt;strong&gt;We follow the transmitted P-wave the goes down&lt;/strong&gt;). &lt;/li&gt;&#xA;&lt;li&gt;That wavefront travels from the outer core into the inner core (which creates 3 wave modes, because there is no &lt;em&gt;reflected&lt;/em&gt; S-wave; &lt;strong&gt;We follow the transmitted S-wave that goes down&lt;/strong&gt;).&lt;/li&gt;&#xA;&lt;li&gt;The S-wave travels through the center of the Earth back up to the interface between inner core and outer core (creating 3 wave modes, because there is no transmitted S-wave; &lt;strong&gt;We follow the P-wave that goes up&lt;/strong&gt;).&lt;/li&gt;&#xA;&lt;li&gt;The P-wave travels through the outer core and hits the interface with the mantle (which creates 3 wave modes because there is no reflected S-wave; &lt;strong&gt;We follow the P-wave that goes up&lt;/strong&gt;).&lt;/li&gt;&#xA;&lt;li&gt;This P-wave further travels to the Earth's crust and surface (creating more wave-modes in the process), and is measured there.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;You can see some of these effects in this nice video: &lt;a href=&quot;https://www.youtube.com/watch?v=j7eoxizmC1I&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=j7eoxizmC1I&lt;/a&gt; that I put in the comments also. It shows P-waves in green and S-waves in red. You can see how complicated the total wavefield becomes because every interface creates new waves...so it'll be a bit hard to see the particular wavefront I described above, but you can see the general picture.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/49s9f.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/49s9f.jpg&quot; alt=&quot;P-wave creates S-wave in inner core&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On this snapshot you see the P-wave (in green) generating an S-wave (in red) in the inner core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So -- S-waves can exist in the inner core even when the outer core doesn't support them (because waves modes &lt;em&gt;convert&lt;/em&gt;, as it's called, at interfaces), and their presence can be measured at the surface. I think that answers your question mostly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then, of course, there is still the question of how you'd measure the speed of the S-waves in the inner core, which is rather complicated. These days, it is done by assuming some seismic model of the earth (choosing V_p, V_s, and \rho everywhere within the Earth), and modeling seismic events such as on the linked YouTube video. Then you compare real recordings against your modeled data. If there are particular misfits, you create a new model and you iterate this procedure until your model fits the recorded data 'well'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So is the shear-wave in the inner core a measured quantity or a deduced quantity? That requires a very careful definition of those terms, so I won't answer that question! Regardless, there &lt;em&gt;exists&lt;/em&gt; a shear-wave velocity for the inner core that describes and explains recorded data very well.&lt;/p&gt;&#xA;" OwnerUserId="12155" LastEditorUserId="12155" LastEditDate="2020-04-04T08:51:05.330" LastActivityDate="2020-04-04T08:51:05.330" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19554" PostTypeId="2" ParentId="19450" CreationDate="2020-04-04T15:14:45.163" Score="0" Body="&lt;p&gt;According to &lt;a href=&quot;https://earthobservatory.nasa.gov/features/CarbonCycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;this NASA documentation&lt;/a&gt;, &#xA;the &lt;strong&gt;fast carbon cycle&lt;/strong&gt;, before anthropogenic climate change had started, had these main characters:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;8 big &lt;strong&gt;carbon reservoirs&lt;/strong&gt; (places &quot;where the carbon stays&quot;), indicated with the following &quot;storage units&quot;:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;deep ocean reservoir (37,000)&lt;/li&gt;&#xA;&lt;li&gt;fossil carbon reservoir (10,000)&lt;/li&gt;&#xA;&lt;li&gt;reactive sediments reservoir (6,000)&lt;/li&gt;&#xA;&lt;li&gt;soil carbon reservoir (2,300)&lt;/li&gt;&#xA;&lt;li&gt;surface ocean reservoir (1,000)&lt;/li&gt;&#xA;&lt;li&gt;atmosphere reservoir (800)&lt;/li&gt;&#xA;&lt;li&gt;plant biomass reservoir (550)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;7 big &lt;strong&gt;carbon fluxes&lt;/strong&gt; (&quot;transitions of carbon&quot;), indicated with the following &quot;flux units&quot; (storage units per amount of time):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Air-sea gas exchange flux - 1° component (90) [ surface ocean reservoir -&gt; athmosphere reservoir ]&lt;/li&gt;&#xA;&lt;li&gt;Air-sea gas exchange flux - 2° component (90) [ athmosphere reservoir -&gt; surface ocean reservoir ]&#xA;&lt;br&gt;&lt;br&gt;&lt;/li&gt;&#xA;&lt;li&gt;Photosynthesis (120) &#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;1° component (???) [ athmosphere reservoir -&gt; plant mass reservoir ]&lt;/li&gt;&#xA;&lt;li&gt;2° component (???) [ athmosphere reservoir -&gt; soil carbon reservoir ]&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;Plant transpiration flux (60) [ plant mass reservoir -&gt; atmosphere reservoir ]&lt;/li&gt;&#xA;&lt;li&gt;Microbial respiration and decomposition flux (60) [ soil carbon reservoir -&gt; atmosphere reservoir ]&#xA;&lt;br&gt;&lt;br&gt;&lt;/li&gt;&#xA;&lt;li&gt;Ocean sediment flux (2) [ surface ocean sorage -&gt; deep ocean reservoir ]&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Please note that without human interaction, the three big environments, that are air, earth and water, are in perfect balance (only inside the water environment, the carbon in surface ocean tends to slowly accumulate in deep ocean).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now here is how fluxes have rearranged after almost 2 centuries that humankind operates its activities on the planet:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;7+1&lt;/strong&gt; big &lt;strong&gt;carbon fluxes&lt;/strong&gt; (&quot;transitions of carbon&quot;), indicated with the following &quot;flux units&quot; (reservoir units per amount of time):&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Antropogenic-alterated&lt;/strong&gt; Air-sea gas exchange flux - 1° component (&lt;strong&gt;90+2&lt;/strong&gt;) [ athmosphere reservoir -&gt; surface ocean reservoir ]&lt;/li&gt;&#xA;&lt;li&gt;Air-sea gas exchange flux - 2° component (90) [ surface ocean reservoir -&gt; athmosphere reservoir ]&#xA;&lt;br&gt;&lt;br&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Antropogenic-alterated&lt;/strong&gt; Photosynthesis (&lt;strong&gt;120+3&lt;/strong&gt;) &#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;1° component (???) [ athmosphere reservoir -&gt; plant mass reservoir ]&lt;/li&gt;&#xA;&lt;li&gt;2° component (???) [ athmosphere reservoir -&gt; soil carbon reservoir ]&lt;/li&gt;&#xA;&lt;/ul&gt;&lt;/li&gt;&#xA;&lt;li&gt;Plant transpiration flux (60) [ plant mass reservoir -&gt; atmosphere reservoir ]&lt;/li&gt;&#xA;&lt;li&gt;Microbial respiration and decomposition flux (60) [ soil carbon reservoir -&gt; atmosphere reservoir ]&#xA;&lt;br&gt;&lt;br&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Human emissions flux (9) [ ??? -&gt; atmosphere reservoir ]&lt;/strong&gt;&#xA;&lt;br&gt;&lt;br&gt;&lt;/li&gt;&#xA;&lt;li&gt;Ocean sediment flux (2) [ surface ocean sorage -&gt; deep ocean reservoir ]&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;h2&gt;Conclusions:&lt;/h2&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;4 carbon [storage unit/time unit] are accumulating in the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;&lt;h2&gt;Notes:&lt;/h2&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Pay special attention on the fact that in this schema we know that human emissions flux unit is 9, and that the flux is only directed to the atmosphere, but we cannot estimate correctly which are the reservoirs feeding those 9 units flux.&lt;br&gt;&#xA;This is because human activities altering the carbon cycle comprehends more than extracting fossil fuels from the deep soil, but also deforesting, waste management, biodiversity reduction and many other &quot;little&quot; activities have an impact on natural fluxes, and the sum effect is that 9 flux units.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also note that in this schema we cannot estimate correctly how carbon amounts in reservoirs have rearranged.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please note that reservoir numbers and flux numbers have different units of measurement and that so they are not mixable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am quite sure that the storage units are Billions of tonnes of carbon (Bt), while It should be irrelevant which are the flux units as long as they are [any mass unit]/[any time unit].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qPoz6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qPoz6.jpg&quot; alt=&quot;Source: https://earthobservatory.nasa.gov/features/CarbonCycle&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20247" LastEditorUserId="5282" LastEditDate="2020-04-08T22:13:28.467" LastActivityDate="2020-04-08T22:13:28.467" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19555" PostTypeId="2" ParentId="2753" CreationDate="2020-04-04T17:13:03.603" Score="1" Body="&lt;p&gt;&lt;strong&gt;Shortly:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Yes, stopping extracting fossil fuels from the deep soil and starting pumping carbon into the deep soil is a feasible and relatively easy solution to stop global warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Full explanation:&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;By assuming that anthropogenic global warming is caused by the rise of greenhouse gases concentration in the atmosphere (let's say mainly CO&lt;sub&gt;2&lt;/sub&gt;), &lt;br&gt;&#xA;in order to stop it, it is necessary to reset it from its actual value (about 415 ppm in February 2020) to the one it was before industrial revolution (around 250 ppm).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This leads to the fact that greenhouse gases emissions related to anthropogenic activities must not just stops, but it has to turn negative, in order to remove the excess of greenhouse gases from the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Given the fact that we can identify &lt;a href=&quot;https://earthscience.stackexchange.com/questions/19450/how-do-the-slow-and-fast-carbon-cycles-influence-climate-change/19554#19554&quot;&gt;8 big carbon reservoirs on our planet and 7 big carbon fluxes&lt;/a&gt; among these reservoirs,&lt;br&gt;&#xA;every activity that contributes to redistribute the fluxes so that, globally, more carbon is drained from the atmosphere and transferred into another reservoir until the atmosphere greenhouse gases concentration reaches 250 ppm, it is a potential solution to global warming.&lt;/p&gt;&#xA;" OwnerUserId="20247" LastEditorUserId="2470" LastEditDate="2020-04-05T03:41:34.560" LastActivityDate="2020-04-05T03:41:34.560" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19556" PostTypeId="2" ParentId="19534" CreationDate="2020-04-04T20:57:51.633" Score="1" Body="&lt;p&gt;QGIS does it easily.&#xA;open the NETCDF (or whatever format the SRTM sits in) by add raster&#xA;right click on the menu item and select export&#xA;choose the file format as .xyz&lt;/p&gt;&#xA;&#xA;&lt;p&gt;DONE!&lt;/p&gt;&#xA;" OwnerUserId="20249" LastActivityDate="2020-04-04T20:57:51.633" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19557" PostTypeId="1" AcceptedAnswerId="19586" CreationDate="2020-04-04T21:07:52.057" Score="2" ViewCount="354" Body="&lt;p&gt;For teaching purposes I am looking for an atmospheric model that can be easily installed and the input data can be easily read and prepared. &#xA;Preferably I would like to run a global low resolution simulation of ~5 years. Naturally, I know this model will not have high forecasting accuracy.&#xA;Is there a model that suits this criteria?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks for the help!&lt;/p&gt;&#xA;" OwnerUserId="20249" LastActivityDate="2020-04-11T19:16:47.413" Title="What is the simplest meteorological model to operate?" Tags="|geophysics|models|weather-forecasting|fluid-dynamics|" AnswerCount="2" CommentCount="4" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19559" PostTypeId="2" ParentId="19542" CreationDate="2020-04-05T06:51:03.663" Score="-1" Body="&lt;p&gt;I was able to do this by the following functions&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;def fill_mismatch(ds_grid_spec, ds_data):&#xA;    ds_data_o = ds_data.copy()&#xA;    count = 0.0&#xA;    for i in range(ds_grid_spec.shape[0]):&#xA;        for j in range(ds_grid_spec.shape[1]):&#xA;            if ds_grid_spec[i,j].values &amp;gt; 0.0 and (not ds_data[i,j] &amp;gt; 0.0):&#xA;                count = count + 1.0&#xA;                fill_miss2d(ds_data_o, i, j)&#xA;            if ds_grid_spec[i,j].values == 0.0 and (not ds_data[i,j].values == 0.0):&#xA;                count = count + 1.0&#xA;                ds_data_o[i,j] = 0.0&#xA;    return ds_data_o&#xA;&#xA;def fill_miss2d(ds, lat_i, lon_j):&#xA;# fist cycle&#xA;    cycle = 1&#xA;&#xA;    while True:&#xA;        bl_i, bl_j = lat_i - cycle, lon_j - cycle&#xA;        tr_i, tr_j = lat_i + cycle, lon_j + cycle&#xA;        # Bottom left i&#xA;        if bl_i &amp;lt; 0:&#xA;            bl_i = 0&#xA;        # Bottom left j&#xA;        if bl_j &amp;lt; 0:&#xA;            bl_j = 0&#xA;        # Top right i&#xA;        if tr_i &amp;gt; ds.lat.shape[0]-1:&#xA;            tr_i = ds.lat.shape[0]-1&#xA;        # Top right j&#xA;        if tr_j &amp;gt; ds.lon.shape[0]-1:&#xA;            tr_j = ds.lon.shape[0]-1&#xA;&#xA;        lats_i = np.arange(bl_i,tr_i)&#xA;        lons_j = np.arange(bl_j,tr_j)&#xA;        for lats_i_idx in lats_i:&#xA;            for lons_j_idx in lons_j:&#xA;                if ds[lats_i_idx, lons_j_idx]&amp;gt;0.0:&#xA;                    ds[lat_i, lon_j] = ds[lats_i_idx, lons_j_idx]&#xA;                    return&#xA;        cycle = cycle + 1&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;The grid_spec (which is the most commonly used grid exchange file for Modular Ocean Model MOM) had a variable AREA_LND and the file soiltype.nc had a variable soiltype. Both these variables had 0.0 at the grid points classified as ocean. Hence we dont need to use fill_miss2d where a mismatch occurs and ocean is encountered in grid_spec, but land is there in soiltype. Rather we directly fill the soiltype grid point with 0.0&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The complete notebook can be found at &lt;a href=&quot;https://github.com/manmeet3591/python_class/blob/master/xarray_tutorial/grid_soiltype.ipynb&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://github.com/manmeet3591/python_class/blob/master/xarray_tutorial/grid_soiltype.ipynb&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18076" LastActivityDate="2020-04-05T06:51:03.663" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19560" PostTypeId="2" ParentId="19534" CreationDate="2020-04-05T07:25:39.350" Score="0" Body="&lt;p&gt;thanks everybody for your comments and reply&#xA;I used the  &lt;em&gt;grdconvert&lt;/em&gt; command  in GMT to convert the mentioned .srtm to .grd format. &lt;/p&gt;&#xA;" OwnerUserId="20228" LastActivityDate="2020-04-05T07:25:39.350" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19561" PostTypeId="2" ParentId="19523" CreationDate="2020-04-05T07:51:01.407" Score="3" Body="&lt;p&gt;I think the answer is 'no', in the sense that 'seismology (i.e., the study of waves propagating within the Earth) tells us the details in a far superior way'. See this paper for an informative treatise: &lt;a href=&quot;https://aapt.scitation.org/doi/citedby/10.1119/1.12026&quot; rel=&quot;nofollow noreferrer&quot;&gt;Brush, S. G. (1980). Discovery of the Earth’s core. &lt;em&gt;American Journal of Physics, 48&lt;/em&gt;, 705-724&lt;/a&gt;, and these lecture notes &lt;a href=&quot;http://www.geo.uu.nl/~berg/geodynamics/lecturenotes.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.geo.uu.nl/~berg/geodynamics/lecturenotes.pdf&lt;/a&gt; on Geodynamics.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Interesting additional tools that you'll find in these works are:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Figuring out the &lt;strong&gt;mass of the Earth&lt;/strong&gt; (using Newton's laws). People found that the average density of the Earth had to be &lt;span class=&quot;math-container&quot;&gt;$5500$&lt;/span&gt; kg/m&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt;, while rocks at the surface only had a density of about &lt;span class=&quot;math-container&quot;&gt;$2700$&lt;/span&gt; kg/m&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt;, so the interior of the Earth had to be of higher density. Under the assumption that pressure alone cannot be responsible for the increase in density, the high densities had to come from chemical changes such as the presence of metals, particularly because of the Earth's magnetic field. Under the assumption that the pressure &lt;em&gt;was&lt;/em&gt; responsible for the high density, the Earth's interior could be gaseous, for example, plain air is more compressible than just rocks, so the Earth's interior could be air (as proposed by Benjamin Franklin in the US!).&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;A second clue that the Earth had to have a radially varying density came from the &lt;strong&gt;Earth's moment of inertia&lt;/strong&gt; (which was a known quantity, based on astronomical measurements such as the &lt;strong&gt;Earth's axial precession&lt;/strong&gt;), which makes it possible to create models that relate density and radius. Of course, with neither quantity well-known, you couldn't do too much with this. But assuming an iron core (with known density, and responsible for the Earth's magnetic field) overlaying a mantle (with density close to that of the Earth's surface), the first radial profiles could be made.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Models could be made that concerned themselves with the rigidity/deformation of the Earth under forces, such as the response to &lt;strong&gt;ocean tides&lt;/strong&gt;, &lt;strong&gt;terrestrial tides&lt;/strong&gt; and the &lt;strong&gt;Chandler wobble&lt;/strong&gt;. These could be used to even construct some radial profiles of some approximate elastic properties. Only in the 1960s, after seismology was a firmly established technique, people additionally found additional non-seismic evidence of the &lt;strong&gt;Earth's eigenvibrations/free oscillations&lt;/strong&gt; where the Earth (as a whole) rings like a bell, which was a very useful independent tool to verify layered profiles of the Earth's elastic properties, and which were important in the discovery of, e.g., the solid inner core.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The rigidity (from the previous point, and mentioned in the first point) can be linked to densities using (thermodynamical) &lt;strong&gt;equations of state&lt;/strong&gt;. Hence, figuring out the appropriate relations between density/pressure/rigidity was of large importance.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Similarly, with the assumption that the Earth was made with the rest of the solar system, it was possible from the &lt;strong&gt;spectral lines of the sun&lt;/strong&gt; and the &lt;strong&gt;chemical makeup of meteorites&lt;/strong&gt; to figure out the likely bulk chemical composition of the Earth (&lt;a href=&quot;https://en.wikipedia.org/wiki/Chondritic_uniform_reservoir&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Chondritic_uniform_reservoir&lt;/a&gt;). If you additionally know the pressure, density and rigidity information, you can make relatively informed guesses about &lt;em&gt;candidate materials&lt;/em&gt; that must be present. That is, similar to the answer by a_donda, one must still test how materials really behave in these strange pressure and temperature regimes, which is mostly laboratory work using, e.g., a &lt;strong&gt;Diamond Anvil Cell&lt;/strong&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Similarly, these lab experiments can tell us that for a given pressure on a given material, what the expected temperatures can be.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;But if you want very solid answers about the 'nature' of the Earth's core, all the most direct answers come straight from seismology. That is the best method to actually constrain the &lt;em&gt;location&lt;/em&gt; of the (elastic) properties within the Earth, at a much higher accuracy than any of the other methods can. As secondary consequences, we can use these measurements to make chemical hypotheses about the makeup of the core etc., but those are entirely based on the assumption that the seismic data is correct....so they're not an 'independent' kind of measurement/model!&lt;/p&gt;&#xA;" OwnerUserId="12155" LastEditorUserId="12155" LastEditDate="2020-04-05T14:51:02.743" LastActivityDate="2020-04-05T14:51:02.743" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19562" PostTypeId="2" ParentId="19548" CreationDate="2020-04-05T07:53:18.403" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Is there a project that tracks and publishes data regarding weather prediction errors on a regular basis that would help with analyzing the correlation between incoming data and prediction error?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The World Meteorological Organization has several initiatives that track forecast performance. See for example &lt;a href=&quot;https://confluence.ecmwf.int//display/WLD&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. The data is a bit delayed, as of today (Apr 5, 2020) the latest month available is February, which was before the strong decrease in AMDAR data.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For assessing forecast performance, one will need to find a forecast field for plotting and a certain metric. As forecast field I like to look at the 500 hPa geopotential height, since this is linked to the atmospheric flow, which itself largely determines surface weather. A suitable metric is the Anomaly Correlation Coefficient (ACC) which basically describes how well the predicted field correlates with the field as it was observed later on at the time for which the prediction was valid.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An intuitive way then to visualize these results, is to look at the forecast lead time at which the forecast reaches a certain threshold of ACC. In the example below this threshold is chosen to be 80%. So one could read the chart as 'how far the model was able to predict ahead', or in short 'predictability'.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The figure below (source: &lt;a href=&quot;https://www.ecmwf.int/en/forecasts/charts/catalogue/plwww_m_hr_ccafreach_ts_hs?facets=Range,Medium%20(15%20days)%3BType,Verification&amp;amp;time=2020031100&amp;amp;area=NHem%20Extratropics&quot; rel=&quot;nofollow noreferrer&quot;&gt;ECMWF&lt;/a&gt;) shows monthly means for this 'Day where ACC=80% is reached' over the Northern Hemisphere. Note the strong seasonal cycle with predictability being much higher in winter compared to summer for the Northern Hemisphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3rVys.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3rVys.png&quot; alt=&quot;ECMWF ACC&quot;&gt;&lt;/a&gt;&#xA;The large seasonality, strong year-to-year variability and in addition overall increases of forecast performance over time (with the model itself being improved over time as well!) will likely make it difficult to attribute any changes of the performance over time to the lower AMDAR coverage.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, there have been several studies analyzing the relevance of different input data (including AMDAR) to the forecast models. I found for example &lt;a href=&quot;https://www.wmo.int/pages/prog/www/OSY/Meetings/NWP5_Sedona2012/2b3_Petersen.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this presentation&lt;/a&gt;. Although this is no conclusive answer to your question, I hope I provided some useful resources.&lt;/p&gt;&#xA;" OwnerUserId="13524" LastActivityDate="2020-04-05T07:53:18.403" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19563" PostTypeId="1" AcceptedAnswerId="19568" CreationDate="2020-04-05T17:48:57.957" Score="0" ViewCount="61" Body="&lt;p&gt;I'm new to the community and this is my first question, I would appreciate in advance your patience and your time to read this post.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm currently processing some oceanographic data such as salinity, oxigen concentration and conductivity, using SeaDataNet's NEMO software, version 1.6.7. I don't know if anybody has used previously NEMO, but I'll describe some basic steps in order to get to the step in which I'm stuck.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The original data file that I'm using is written in CNV format (not CSV), I provide this screenshot &lt;a href=&quot;https://i.stack.imgur.com/IxfAJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IxfAJ.png&quot; alt=&quot;this screenshot&quot;&gt;&lt;/a&gt; and this one &lt;a href=&quot;https://i.stack.imgur.com/wkSYV.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wkSYV.png&quot; alt=&quot;this one&quot;&gt;&lt;/a&gt; since I can't upload any data file.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This file won't work so that I've given exactly the same data but formatted in another way, this is the other one &lt;a href=&quot;https://i.stack.imgur.com/rZeLT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rZeLT.png&quot; alt=&quot;this is the other one&quot;&gt;&lt;/a&gt;, with this data &lt;a href=&quot;https://i.stack.imgur.com/cxurN.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cxurN.png&quot; alt=&quot;with this data&quot;&gt;&lt;/a&gt; The first file's header contains some information written in Spanish, since the institution for which I work is &lt;em&gt;Instituto Español de Oceanografía&lt;/em&gt;. I'm using the latter file.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll skip right to the &lt;em&gt;data&lt;/em&gt; tab, since the question might get too long and I haven't had any problem in validating every previous step.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In &lt;em&gt;data&lt;/em&gt; tab, in the table below in &lt;a href=&quot;https://i.stack.imgur.com/eqCrV.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eqCrV.png&quot; alt=&quot;this image&quot;&gt;&lt;/a&gt;  I select all necessary parameters: pressure (PRES), temperature (TEMP), conductivity (CNDC), oxigen concentration (DOX1) and salinity (PSAL). Data starts at line 35.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;After that I go with pressure data: I select the first line of the pressure data (1.0 in this image) &lt;a href=&quot;https://i.stack.imgur.com/I4Ui0.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/I4Ui0.png&quot; alt=&quot;this image&quot;&gt;&lt;/a&gt; and then right clicking choose the &lt;em&gt;start/end&lt;/em&gt; option so that NEMO stores the position of that data on that line. Units and format are automatically stored because there is already information about them on the new data file. I repeat the process with &lt;em&gt;output def.value&lt;/em&gt; choosing the -999.9 value at the bottom, like this:[&lt;img src=&quot;https://i.stack.imgur.com/QI56u.png&quot; alt=&quot;like this [7]&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do the same with the rest of the parameters. Now in order to validate this step, I first have to test every value and for that I choose the &lt;em&gt;update test&lt;/em&gt; option, so in principle in the &lt;em&gt;test&lt;/em&gt; column (next to &lt;em&gt;conversion&lt;/em&gt; column) those first parameter values should appear according to the output format (&lt;em&gt;format&lt;/em&gt; column).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem is that nothing appears in the &lt;em&gt;test&lt;/em&gt; column. I've tried several times repeating the process from scratch without getting any error message when validating steps, but every time I get to the data tab, choose parameters, select the right start/end and try to update test, it continues appearing nothing. Besides, if I try anyway to validate the step, I get no error or succes message in the log tab at the bottom of the program screen. At this step the program doesn't let me change nothing else.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Am I doing something wrong though I don't get error messages? I have read several times the manual, and there is no any troubleshooting tip about this issue. Apart from that, is there any program to accomodate data so that I convert data as on image 2 to that appearing in image 4?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Any help would be greatly appreciated as I really need to go on. Thank you again for your patience and for taking your time to read the whole post.&lt;/p&gt;&#xA;" OwnerUserId="20255" LastEditorUserId="20255" LastEditDate="2020-04-06T10:38:07.530" LastActivityDate="2020-04-06T13:00:11.370" Title="SeaDataNet's NEMO software, stuck on data validation?" Tags="|oceanography|data-analysis|software|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19564" PostTypeId="1" CreationDate="2020-04-05T22:49:43.653" Score="4" ViewCount="1296" Body="&lt;p&gt;I'm pulling air temperature and other weather stats from various APIs. There's this concept called &quot;feels like temperature&quot;, separate from &quot;actual temperature&quot;. Apparently, this is the temperature that it &lt;em&gt;feels&lt;/em&gt; like to a human, depending on the wind speed and other factors.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this determined, as the name suggests, by a human who &quot;feels&quot; it? Or is it mathematically calculated based on the other data such as the wind speed, so that it isn't actually &quot;felt&quot; by a human at all, but rather is a scientific estimation of how a human probably &quot;will feel&quot; the temperature?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Personally, I have no idea how anyone can &quot;feel&quot; the temperature in specific terms; to me, it's either &quot;freezing&quot;, &quot;cold&quot;, &quot;chilly&quot;, &quot;OK&quot;, &quot;warm&quot;, &quot;hot&quot; and &quot;unbearable&quot; -- any guess I would make about what temperature it &quot;feels like&quot; would vary with each time you asked me and not be accurate whatsoever.&lt;/p&gt;&#xA;" OwnerUserId="20256" LastActivityDate="2023-12-19T14:09:19.930" Title="How do they determine the &quot;feels like&quot; temperatures for weather data?" Tags="|meteorology|weather-forecasting|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19565" PostTypeId="2" ParentId="19564" CreationDate="2020-04-06T03:16:57.597" Score="1" Body="&lt;p&gt;The &quot;feels like&quot; value is calculated based on temperature, but altered depending on wind (cold temperatures) or humidity (hot temperatures).  Think of it this way:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) if it's freezing cold outside, the wind will make if seem even colder because any body heat you have will be blown away quickly.&lt;br&gt;&#xA;2) if it's hot outside, high humidity will make it seem even hotter because your sweat won't easily evaporate.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From &lt;a href=&quot;https://www.wunderground.com/maps/temperature/feels-like&quot; rel=&quot;nofollow noreferrer&quot;&gt;wunderground&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Feels Like Temperatures map show what the outdoor temperature will feel like for the current day. Feels Like Index is a factored mixture of the Wind Chill Factor and the Heat Index. The combination of the heat index and the wind chill factor are denoted collectively by the single terms apparent temperature or relative outdoor temperature or simply Feels Like.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Wind Chill&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Wind chill is the apparent temperature felt on exposed skin, which is a function of the air temperature and wind speed. The wind chill temperature (often popularly called the wind chill factor) is always lower than the air temperature, except at higher temperatures where wind chill is considered less important. In cases where the apparent temperature is higher than the air temperature, the heat index is used instead.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Heat Index&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The heat index (HI) is an index that combines air temperature and dew point in an attempt to determine the human-perceived equivalent temperature — how hot it feels, termed the felt air temperature. The human body normally cools itself by perspiration, or sweating, which evaporates and carries heat away from the body. However, when the relative humidity is high the evaporation rate is reduced, so heat is removed from the body at a lower rate causing it to retain more heat than it would in dry air. Measurements have been taken based on subjective descriptions of how hot subjects feel for a given temperature and humidity, allowing an index to be made which corresponds a temperature and humidity combination to a higher temperature in dry air.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The heat index is derived from work carried out by R. G. Steadman. Like the wind chill index, the heat index contains assumptions about the human body mass and height, clothing, and the wind speed. Significant deviations from these will result in heat index values which do not accurately reflect the perceived temperature.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastActivityDate="2020-04-06T03:16:57.597" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19566" PostTypeId="1" CreationDate="2020-04-06T05:18:13.723" Score="6" ViewCount="837" Body="&lt;p&gt;The Space SE question &lt;a href=&quot;https://space.stackexchange.com/q/43273/12102&quot;&gt;How much does it cost to land on a lunar mascon?&lt;/a&gt; includes the background information below. I am sure it's not too hard to find a link where spherical harmonic coefficients for some model of the Moon's gravity can be found, but the hard part is to turn them into an actual vector force field in units of m/s&lt;sup&gt;2&lt;/sup&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Likely the coefficients will be for the gravitational potential, and there will be some method to take the gradient to obtain a field, but I have never been able to make sense of this kind of data. For example see:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://space.stackexchange.com/q/27689/12102&quot;&gt;Ceres gravity from spherical harmonics from Dawn, how to get the coefficients, definitions and potential?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://space.stackexchange.com/q/27779/12102&quot;&gt;How can I verify my reconstructed gravity field of Ceres from spherical harmonics?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CEllE.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CEllE.jpg&quot; alt=&quot;These maps of the moon show gravity anomalies measured by NASA's GRAIL mission. (Image credit: NASA/JPL-Caltech/CSM) &quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;These maps of the moon show gravity anomalies measured by NASA's GRAIL mission. (Image credit: NASA/JPL-Caltech/CSM)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;From Space.com's &lt;a href=&quot;https://www.space.com/21364-moon-gravity-mascons-mystery.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mystery of Moon's Lumpy Gravity Explained&lt;/a&gt;, click for full size.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Bouguer_anomaly&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bouguer anomaly plots&lt;/a&gt; show elevated gravity as much as about 600 mGal. Wikipedia's &lt;a href=&quot;https://en.wikipedia.org/wiki/Gal_(unit)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gal (unit)&lt;/a&gt; explains what this means; 0.6 Gal is 0.006 m/s&lt;sup&gt;2&lt;/sup&gt; or almost a half of a percent of the Moon's average gravity, and they extend over quite large distances.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The gal (symbol: Gal), sometimes called galileo after Galileo Galilei, is a unit of acceleration used extensively in the science of gravimetry. The gal is defined as 1 centimeter per second squared (1 cm/s&lt;sup&gt;2&lt;/sup&gt;). The milligal (mGal) and microgal (µGal) are respectively one thousandth and one millionth of a gal.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="2470" LastEditDate="2022-02-03T09:36:26.600" LastActivityDate="2022-02-18T02:52:18.020" Title="How to make a Python function return the Moon's gravitational force (acceleration) to calculate orbits?" Tags="|open-data|moon|gravity|" AnswerCount="1" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="19567" PostTypeId="2" ParentId="19548" CreationDate="2020-04-06T07:09:51.090" Score="2" Body="&lt;p&gt;The ECMWF (European Centre for Medium-Range Weather Forecasts) has published an article about the topic on 24 March 2020:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;By 23 March there was a reduction of 65% in [European aircraft] reports received compared to 3 March. Globally the reduction was about 42%. [...]&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;In 2019 a test was run: a series of forecasts &lt;strong&gt;without using aircraft reports&lt;/strong&gt; (but with all other data) [...], compared to using all data (i.e. including aircraft reports). [...]&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&lt;strong&gt;12-hour temperature forecasts&lt;/strong&gt; in the northern hemisphere are more than &lt;strong&gt;9% worse at cruise levels&lt;/strong&gt;. [...]&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;&quot;Removing half the aircraft reports would be expected to give slightly less than half the impact of removing all aircraft,&quot; says ECMWF scientist Bruce Ingleby. [...]&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;In summary, the number of aircraft observations has gone down significantly over the last couple of weeks both over Europe and globally. In the coming days and weeks, we expect a further decrease in numbers, which will have &lt;strong&gt;some impact&lt;/strong&gt; on forecast quality &lt;strong&gt;in the short range&lt;/strong&gt;, particularly around the polar jet stream level (&lt;strong&gt;10-12 km altitude&lt;/strong&gt;).&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Sensitivity studies at ECMWF have shown that removing all aircraft data &lt;strong&gt;degrades&lt;/strong&gt; the &lt;strong&gt;short-range wind and temperature forecasts at those levels by up to 15%&lt;/strong&gt;, with significant degradations at all forecast ranges up to seven days. There is a smaller, but still statistically significant, &lt;strong&gt;impact on near-surface fields, up to 3%&lt;/strong&gt; on surface pressure.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;Other types of observations are likely to be less affected by the COVID-19 disruption than aircraft reports, and there may be some additional radiosonde launches to try to mitigate the lack of aircraft data.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;(emphasis mine)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.ecmwf.int/en/about/media-centre/news/2020/drop-aircraft-observations-could-have-impact-weather-forecasts&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ecmwf.int/en/about/media-centre/news/2020/drop-aircraft-observations-could-have-impact-weather-forecasts&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20240" LastActivityDate="2020-04-06T07:09:51.090" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19568" PostTypeId="2" ParentId="19563" CreationDate="2020-04-06T13:00:11.370" Score="0" Body="&lt;p&gt;You are having an issue with a specific software developed/mantained by a certain institution. You may be luckier in directly contacting people responsible for the software at that institution.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Please check this presentation to find relevant persons to your issue.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://archimer.ifremer.fr/doc/00454/56547/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://archimer.ifremer.fr/doc/00454/56547/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;or contacting the official NEMO's email sdn-userdesk@seadatanet.org and/or ask about this person &lt;a href=&quot;https://annuaire.ifremer.fr/cv/16035/en/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://annuaire.ifremer.fr/cv/16035/en/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Finally, there is some &quot;program to accomodate data so that I convert data as on image 2 to that appearing in image 4&quot;: what you want to do is to manipulate ascii-data, there are tons of tools.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would use either perl or python, even notepad++ may be helpful, but it is not exactly clear what you would like to get accomplished (it is not clear which one are images 2 and 4, sorry, your post&amp;amp;figures are clogging us with too much information in an unclear way, try at least to crop the picture, to show only the relevant piece of information we need) &lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2020-04-06T13:00:11.370" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19570" PostTypeId="1" CreationDate="2020-04-06T23:10:00.663" Score="1" ViewCount="83" Body="&lt;p&gt;Note the use of the term removed instead of melted—as in, any excess water is moved to where it can't cause trouble, either through the use of advanced technology (space elevators, et cetera) or for the sake of having a simplistic model.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Almost exactly 1 year ago, I asked &lt;a href=&quot;https://www.quora.com/If-the-Antarctic-ice-sheet-were-removed-under-modern-climatic-conditions-assuming-the-excess-water-is-somehow-moved-off-world-so-theres-no-net-sea-level-change-how-would-the-climate-of-Antarctica-and-the-world-at/&quot; rel=&quot;nofollow noreferrer&quot;&gt;a very similar question on Quora&lt;/a&gt;, to which I got only &lt;a href=&quot;https://www.quora.com/If-the-Antarctic-ice-sheet-were-removed-under-modern-climatic-conditions-assuming-the-excess-water-is-somehow-moved-off-world-so-theres-no-net-sea-level-change-how-would-the-climate-of-Antarctica-and-the-world-at/answer/Barry-Lewis-6/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this answer&lt;/a&gt;, which I vigorously disagreed with &lt;a href=&quot;https://www.quora.com/If-the-Antarctic-ice-sheet-were-removed-under-modern-climatic-conditions-assuming-the-excess-water-is-somehow-moved-off-world-so-theres-no-net-sea-level-change-how-would-the-climate-of-Antarctica-and-the-world-at/answer/Barry-Lewis-6/comment/91840662&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. Nevertheless, the use of the term &quot;under present climatic conditions&quot; may have led him to assume the climate is also somehow held constant rather than being influenced by the changes (just not by anthropogenic greenhouse gases), and the massive scope of the question probably discouraged more people from answering. I hope this wording will be more clear.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That answer assumed a rapid and catastrophic re-attainment of the status quo. My disagreement comes from several factors that would act in tandem to warm its climate:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;strong&gt;Lower elevation within the troposphere.&lt;/strong&gt; The lapse rates described in the paper &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/1999GL900536&quot; rel=&quot;nofollow noreferrer&quot;&gt;Altitude dependence on the ice sheet surface climate&lt;/a&gt; imply that &lt;em&gt;ignoring other factors&lt;/em&gt;, Vostok Station would be 23.6–26.5 °C warmer without the elevation of the ice depending on the season and assumptions made, while the temperature at Amundsen–Scott would increase by 17.7–21.5 °C. This effect would be less the closer the glacial surface is to the subglacial terrain or sea level.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Greater solar heating.&lt;/strong&gt; Ice can reflect 90% or more of its incident solar energy, while bare rock typically has a far lower albedo, with around 10–40% of solar energy reflected, with the rest absorbed to heat up itself and the air. Open water has an extremely low albedo, with only ~6% of solar energy reflected. Even at the South Pole, provided skies are clear and atmospheric conditions are ideal, solar heating alone can sustain liquid water for about 84 days†. The actual decrease in (year-round average) albedo wouldn't be as significant due to seasonal snow/ice cover, but as solar energy is massively concentrated in the summer at Antarctic latitudes, the effective albedo would still be much less.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Topography and other effects allowing warm ocean currents and air masses to move southward.&lt;/strong&gt; The general warming of the Antarctic would cause the maximum-density Antarctic Circumpolar Current to move southward, with subtropical currents such as the Brazil, Agulhas, and East Australian currents pushing southward and providing a Gulf Steam-like influence. The lower elevation of the interior would also allow (warm) weather fronts from lower latitudes to penetrate deep into the continent.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;As implied all throughout this, there would be negative feedbacks causing reglaciation, and said glaciation would stop at some point, but the point of contention is when and where, i.e. how negative the second derivative of glacial area is. So, with all the factors taken into account, what would be the answer? Is Barry Lewis correct or not?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;†This was roughly calculated by combining solar angle with the Stefan-Boltzmann law at the albedo of open water, with an estimate of the atmospheric absorption and reflection given absolutely ideal atmospheric conditions adjusted by angle.&lt;/p&gt;&#xA;" OwnerUserId="17317" LastEditorUserId="2470" LastEditDate="2021-07-06T06:56:19.590" LastActivityDate="2021-07-06T06:56:19.590" Title="If its ice sheet were removed under modern atmospheric conditions, what climatic and ice-sheet equilibrium would be re-established over Antarctica?" Tags="|meteorology|climate|glaciology|hypothetical|antarctica|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19571" PostTypeId="1" CreationDate="2020-04-07T10:19:56.200" Score="3" ViewCount="359" Body="&lt;p&gt;Taking a sounding prediction from GFS 1° horizontal resolution(from ready.arl.noaa.gov) with &lt;strong&gt;normal pressure&lt;/strong&gt; levels looks like this:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;PRESS HGT(MSL) TEMP DEW PT  WND DIR  WND SPD&#xA; hPa       m      C     C       DEG     m/s  &#xA; E = Estimated Surface Height&#xA;&#xA;  969.   438.    6.7    5.4   358.8     3.3&#xA;  950.   586.    5.1    4.4     1.8     5.0&#xA;  925.   803.    3.6    3.0    14.6     5.5&#xA;  900.  1025.    2.2    1.7    28.8     6.6&#xA;  850.  1485.   -0.2   -0.4    48.6     9.7&#xA;  800.  1970.   -2.2   -2.5    60.6    11.1&#xA;  750.  2480.   -4.6   -4.9    66.1    11.3&#xA;  700.  3020.   -7.0   -7.3    65.0    11.0&#xA;  650.  3597.   -8.9   -9.4    63.7    11.5&#xA;  600.  4215.  -10.9  -13.8    72.1    11.7&#xA;  550.  4878.  -15.3  -20.1    76.3     9.3&#xA;  500.  5591.  -20.6  -22.6    87.2     7.3&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;But doing the same with GFS 0.25° horizontal resolution that is given only in &lt;strong&gt;Hybrid-sigma pressure&lt;/strong&gt; levels seems like this (for the same area and time and GFS run):&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;&#xA;    PRESS HGT(MSL) TEMP DEW PT  WND DIR  WND SPD&#xA;     hPa       m      C     C       DEG     m/s  &#xA;     E = Estimated Surface Height&#xA;    &#xA;      998.   186.E&#xA;      995.   213.E   7.6    5.9    34.7     2.1&#xA;      990.   287.E   7.5    5.5    33.3     3.1&#xA;      983.   369.E   7.0    5.0    35.3     3.6&#xA;      975.   475.E   6.6    4.4    34.1     4.3&#xA;      967.   575.E   6.1    3.8    31.6     4.8&#xA;      958.   686.E   5.6    3.4    31.9     5.2&#xA;      948.   828.E   5.1    2.9    29.9     5.6&#xA;      936.   982.E   4.4    2.3    33.9     6.0&#xA;      923.  1147.E   3.8    1.9    36.5     6.7&#xA;      908.  1355.E   3.0    1.5    41.6     8.0&#xA;      893.  1572.E   2.2    1.2    46.3     9.4&#xA;      875.  1827.E   1.2    0.7    51.2    10.7&#xA;      856.  2111.E   0.3   -0.1    55.3    11.5&#xA;      835.  2426.E  -0.5   -0.9    59.1    11.9&#xA;      811.  2795.E  -1.5   -1.8    61.9    11.7&#xA;      786.  3189.E  -2.5   -2.8    64.3    11.2&#xA;      760.  3610.E  -3.9   -4.3    65.7    11.1&#xA;      731.  4093.E  -5.2   -5.6    65.7    11.1&#xA;      701.  4608.E  -7.7   -8.1    65.6    11.4&#xA;      670.  5168.E  -8.5   -8.9    67.9    12.2&#xA;      637.  5789.E  -9.2   -9.9    67.0    13.0&#xA;      603.  6443.E -11.1  -12.6    64.4    13.0&#xA;      568.  7135.E -14.0  -15.4    64.4    11.0&#xA;      533.  7863.E -17.6  -19.2    82.7     8.0&#xA;      498.  8582.E -20.8  -25.2    98.2     8.0&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;First normal sounding says that GFS's prediction about where 500 hPa would lie is 5591 meters geopotential height. Which is a normal value. But, the 2nd sounding with hybrid-sigma pressure levels says 498≈500 hPa level is on 8582 meters which is absurd.&lt;/p&gt;&#xA;&lt;p&gt;So my question is how to convert geopotential heights of the hybrid-sigma pressure levels to normal in order to know where the real height of e.g 850 hPa is? Since I can find from the 1st sounding at which heights 850 hPa lies, but from the 2nd I can't.&lt;/p&gt;&#xA;&lt;p&gt;Or, how to convert hybrid-sigma pressure levels to normal pressure levels?&lt;/p&gt;&#xA;&lt;p&gt;Ready.ARL.NOAA has a guide(&lt;a href=&quot;https://ready.arl.noaa.gov/READYmetdata.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://ready.arl.noaa.gov/READYmetdata.php&lt;/a&gt;) of what hybrid-sigma-levels correspond to GFS, but it doesn't seem to provide a way of doing anything of what i want.&lt;/p&gt;&#xA;" OwnerUserId="20257" LastEditorUserId="2470" LastEditDate="2022-11-11T17:27:19.303" LastActivityDate="2022-11-11T17:27:19.303" Title="Hybrid-Sigma pressure levels and geopotential heights" Tags="|pressure|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19573" PostTypeId="1" AcceptedAnswerId="19574" CreationDate="2020-04-08T16:05:31.853" Score="-1" ViewCount="574" Body="&lt;p&gt;&lt;strong&gt;How has the increase in global CO2 been attributed to an anthropogenic cause?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;It would seem to me that this could be definitively determined on the basis of placing gas spectrometers on the exhausts of a stratified random sample of exhaust pipes: (a) Motor vehicles, (b) Aircraft (c) smoke stacks of factories. et cetera.  Has this been done or are we just guessing?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;There is a very great answer show below that essentially says from:&lt;/strong&gt;&lt;br&gt;&#xA;(a) The known GHG emissions of the fossil fuels &lt;br&gt;&#xA;(b) The known fossil fuel consumption for last year&lt;br&gt;&#xA;(c) The known increase in atmospheric GHG last year&lt;br&gt;&#xA;we can use simple arithmetic to determine how much of this emission has an anthropogenic cause.&lt;/p&gt;&#xA;&lt;p&gt;Because the ocean is such a powerful GHG sink, I would expect that the above process might account for more than 100% of the increase of atmospheric GHG.&lt;/p&gt;&#xA;&lt;h1&gt;I am still trying to find the data to quantify the above&lt;/h1&gt;&#xA;&lt;p&gt;&lt;strong&gt;The EPA relied on the IPCC assessment:&lt;/strong&gt; &lt;br&gt;&#xA;Human activities are responsible for almost all of the increase in greenhouse gases in the atmosphere over the last 150 years.1&#xA;&lt;a href=&quot;https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions&lt;/a&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;IPCC (2007). Summary for Policymakers. In: Climate Change 2007: The Physical Science Basis.&lt;br&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;h1&gt;This graph shows all CO2 emissions and how much goes into the atmosphere, thus proving that humans cause much more than all of the increase of CO2 in the atmosphere.&lt;/h1&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kVgZd.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kVgZd.png&quot; alt=&quot;https://www.carbonbrief.org/what-global-co2-emissions-2016-mean-climate-change&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.carbonbrief.org/wp-content/uploads/2016/11/GlobalCarbonBudget_3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.carbonbrief.org/wp-content/uploads/2016/11/GlobalCarbonBudget_3.png&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17970" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-04-13T14:55:00.057" Title="How has the increase in global CO2 been attributed to an anthropogenic cause?" Tags="|climate-change|co2|greenhouse-gases|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19574" PostTypeId="2" ParentId="19573" CreationDate="2020-04-08T16:55:01.520" Score="1" Body="&lt;p&gt;There are multiple ways of determining this, but the simplest, which doesn't require any high-tech monitoring devices on exhaust pipes and the like, is simply to determine how much fossil fuel (coal, oil, &amp;amp;c) is mined each year.  This economic data is readily available from for instance the CIA World Factbook: &lt;a href=&quot;https://www.cia.gov/library/publications/the-world-factbook/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.cia.gov/library/publications/the-world-factbook/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From this, you do a bit of simple chemistry, e.g. every 12 tons of coal burned produces 44 tons of CO2.  Compare the amount produced with the measured increase in CO2, and you'll find they match.  QED&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2020-04-08T16:55:01.520" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19575" PostTypeId="1" CreationDate="2020-04-08T18:43:35.180" Score="1" ViewCount="21" Body="&lt;p&gt;The grib2 format has a field listed under table 4.212 giving the land use code.  Does anyone know where I can download data containing this field?&lt;/p&gt;&#xA;" OwnerUserId="18975" LastActivityDate="2020-04-08T18:43:35.180" Title="Land Use grib2 Table 4.212 download?" Tags="|land-surface|gfs|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19576" PostTypeId="2" ParentId="19573" CreationDate="2020-04-08T21:36:29.267" Score="1" Body="&lt;p&gt;The question is too generic to be specifically answered in few lines.&lt;br&gt;&#xA;The answer to this question is the history of climate change science itself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can find a good essay here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/03/ar4-wg1-chapter1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Historical Overview of Climate Change Science&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But to understand it, you probably need to start from here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/02/ar4-wg1-chapter9-1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Understanding and Attributing Climate Change&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;IMHO even in these essays you won't find a quick and short answer to your answer.&lt;br&gt;&#xA;These whole essays represent a part of the answer to your question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also note that climate change is not just linked to gases emissions, but to anthropic-induced changes in the natural carbon cycles. This means that also land use change (intensive agriculture, intensive farming, deforestation) is responsible for climate change, even if &quot;there is no chimney&quot;.&lt;/p&gt;&#xA;" OwnerUserId="20247" LastEditorUserId="20247" LastEditDate="2020-04-08T21:48:05.277" LastActivityDate="2020-04-08T21:48:05.277" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19577" PostTypeId="1" AcceptedAnswerId="19582" CreationDate="2020-04-09T12:22:25.250" Score="1" ViewCount="257" Body="&lt;p&gt;The report's respective ratio of 1 passenger car vs one long haul plane are 40% versus 110%: &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image 1 (DEFRA):&lt;br&gt;&#xA;car = 171 plane  = 195 (110%) &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Image 2 (EPA):&lt;br&gt;&#xA;car = 4096 plane = 1760 (40%)  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the us uses petrol, it should be the other way around if anything&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A car exhaust is at 50cm altitude, versus a plane at 10km altitude. The atmospheric lifetimes of the heavy fumes should therefore be different in the EPA's 100 year atmospheric lifetime indices.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why do the reports have a ratio of 40% vs 110 % GWP CO2 equivalent for a car vs a plane?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IHrrO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IHrrO.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;EPA source:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mDsEh.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mDsEh.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2020-04-09T18:58:16.263" LastActivityDate="2020-04-10T16:49:38.220" Title="USA and UK government report on plane emissions: 200% difference... which is right?" Tags="|atmosphere|climate-change|greenhouse-gases|emissions|" AnswerCount="2" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="19578" PostTypeId="2" ParentId="19577" CreationDate="2020-04-09T14:43:19.603" Score="4" Body="&lt;p&gt;&lt;strong&gt;The unit is different.&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The British data is in gram per passenger per &lt;em&gt;kilometer&lt;/em&gt; travelled, while the US data is in gram per passenger per &lt;em&gt;mile&lt;/em&gt; traveled.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;1 mile = 1.609 km&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;So if you take the long haul flight, 102 g/km (UK) = 164 g/mi, which is almost similar to the US figure of 166 g/mi.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-04-09T14:43:19.603" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19579" PostTypeId="1" CreationDate="2020-04-09T23:25:09.267" Score="6" ViewCount="337" Body="&lt;p&gt;I frequently see lines like this (the red arrows in the image below point to what I am referring to) on doppler radars. They are usually propagating outward from a line of thunderstorms.&lt;/p&gt;&#xA;&lt;p&gt;What are they, what do they indicate, and how do they form?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JOlxI.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JOlxI.png&quot; alt=&quot;Doppler Radar Image&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20274" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-06-10T19:03:55.360" Title="What are these lines that I frequently see on doppler radar?" Tags="|meteorology|radar|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19580" PostTypeId="1" AcceptedAnswerId="20913" CreationDate="2020-04-10T00:03:06.040" Score="3" ViewCount="109" Body="&lt;p&gt;The April 9, 2020 NASA press release &lt;a href=&quot;https://www.nasa.gov/press-release/nasa-astronaut-chris-cassidy-crewmates-arrive-safely-at-space-station&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA Astronaut Chris Cassidy, Crewmates Arrive Safely at Space Station&lt;/a&gt; mentions:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;It is the third spaceflight for Cassidy and Ivanishin and the first for Vagner, who are scheduled to return to Earth in October after a mission of more than six months during which they will conduct about 160 &lt;a href=&quot;https://www.nasa.gov/mission_pages/station/research/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;science investigations&lt;/a&gt; in fields such as, biology, &lt;strong&gt;Earth science&lt;/strong&gt;, human research, physical sciences, and technology development. Work on the unique microgravity laboratory advances scientific knowledge and demonstrates new technologies, making research breakthroughs that will enable long-duration human and robotic exploration of the Moon and Mars.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;What scientific investigations into Earth Science will these three astronauts do between now and their return to Earth in October?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2021-02-26T23:50:55.807" LastActivityDate="2021-02-27T09:16:33.430" Title="What Earth Science research will be done from the International Space Station?" Tags="|earth-observation|reference-request|orbit|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19582" PostTypeId="2" ParentId="19577" CreationDate="2020-04-10T16:49:38.220" Score="5" Body="&lt;p&gt;I've looked into this briefly and noticed a few things that are worth pointing out.  First, your EPA table looks like it was based on Table 8 of this EPA pdf:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.epa.gov/sites/production/files/2018-03/documents/emission-factors_mar_2018_0.pdf&quot; rel=&quot;noreferrer&quot;&gt;https://www.epa.gov/sites/production/files/2018-03/documents/emission-factors_mar_2018_0.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There’s a note in the table that,&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Air Travel factors from 2017 Guidelines to Defra / DECC's GHG&#xA;  Conversion Factors for Company Reporting. Version 1.0 August 2017.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;So, with a lovely bit of irony, &lt;strong&gt;those EPA air travel numbers are taken from the UK/DECC/Defra&lt;/strong&gt;, which are available here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2017&quot; rel=&quot;noreferrer&quot;&gt;https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2017&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that they’ve translated the names of the air travel distance categories so they make sense in the US market:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;US short-haul (&amp;lt; 300 mi) = UK domestic (UK to UK)&lt;/li&gt;&#xA;&lt;li&gt;US medium-haul (300 - 2300 mi) = UK short-haul (&amp;lt; 3700 km)&lt;/li&gt;&#xA;&lt;li&gt;US long-haul (&gt; 2300 mi) = UK long-haul (&gt; 3700 km)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Taking some numbers from US short-haul/UK domestic as an example, the CO2 emissions are,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;0.14002 kgCO2e/pass km = 140.02 gCO2e/pass km = 225.3 gCO2e/pass mi&lt;/p&gt;&#xA;&#xA;&lt;p&gt;which is just basic units conversion and agrees with your EPA table and the EPA pdf.  The same is true for the CO2 emissions in the other distance categories.  Note that &lt;strong&gt;the EPA are using the numbers for the CO2e emissions without radiative forcing feedbacks&lt;/strong&gt; from water vapor, contrails, NOx, etc., which is the dark blue portion of the bars in your plot from the BBC.  You should be comparing that portion of the emissions, not the full bar including the light blue.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There's a further problem with the CH4 and N2O values in your EPA table.  Taking the same example as above but for CH4 emissions,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;0.00006 kgCO2e/pass km = 0.06 gCO2e/pass km = 0.097 gCO2e/pass mi = 0.0039 gCH4/pass mi&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is correct in the EPA pdf, but &lt;strong&gt;has been mis-transcribed in your EPA table&lt;/strong&gt; as 3.9 gCH4/pass mi.  Oops! someone got confused between grams and kilograms, and they've made the same mistake in the CH4 and N2O entries for all modes of transport.  They’ve then used this to calculate the overall GWP column, so their values are oversensitive to CH4 and N2O:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;GWP = 225*1 + 3.9*25 + 7.2*298 = 2468.1&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The correct calculation is,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;GWP = 225*1 + 3.9e-3*25 + 7.2e-3*298 = 227&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The bottom line is that I think the GWP column in your EPA table is nonsense and the aircraft emissions factors have the same source (albeit the BBC are probably using more recent UK emission factors).  The respective CO2 emissions for cars in the sources I've linked to aren't wildly different (297 gCO2/mi in UK, 343 gCO2/mi in US) and for motorcycles are almost identical (183 gCO2/mi in UK, 189 gCO2/mi in US).&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2020-04-10T16:49:38.220" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19583" PostTypeId="2" ParentId="19557" CreationDate="2020-04-11T10:09:39.700" Score="2" Body="&lt;p&gt;Weather forecasting (meteorology) is not climate modelling. As such, a meteorological model to forecast temperatures over years is not the right tool for the job.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But there is indeed a very, very simple climate &quot;model&quot; that only accounts for CO&lt;sub&gt;2&lt;/sub&gt; and temperature.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You find it here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://scied.ucar.edu/simple-climate-model&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://scied.ucar.edu/simple-climate-model&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;with a little guide:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://scied.ucar.edu/activity/very-very-simple-climate-model-activity&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://scied.ucar.edu/activity/very-very-simple-climate-model-activity&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and more info here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.windows2universe.org/?page=/teacher_resources/teach_climatemodel.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.windows2universe.org/?page=/teacher_resources/teach_climatemodel.html&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The question was &quot;simple&quot;, and this is simple. It only shows a single dependency but may be useful to demonstrate a relationship. Of course &quot;real&quot; quantitative modelling depends on ridiculously much more and is constantly improved and updated.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorUserId="2470" LastEditDate="2020-04-11T18:39:52.520" LastActivityDate="2020-04-11T18:39:52.520" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19584" PostTypeId="2" ParentId="9588" CreationDate="2020-04-11T12:20:12.900" Score="2" Body="&lt;p&gt;Here's one actual example of a marine ecosystem releasing a huge amount of CO&lt;sub&gt;2&lt;/sub&gt; because of a marine heat wave, i.e. where climate change leads to more CO&lt;sub&gt;2&lt;/sub&gt; release:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Arias-Ortiz et.a. &lt;a href=&quot;https://www.nature.com/articles/s41558-018-0096-y&quot; rel=&quot;nofollow noreferrer&quot;&gt;A marine heatwave drives massive losses from the world’s largest seagrass carbon stocks&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;On the basis of field studies and satellite imagery, we estimate that 36% of Shark Bay’s seagrass meadows were damaged following a marine heatwave in 2010/2011. Assuming that 10 to 50% of the seagrass sediment C stock was exposed to oxic conditions after disturbance, between 2 and 9 Tg CO&lt;sub&gt;2&lt;/sub&gt; could have been released to the atmosphere during the following three years, increasing emissions from land-use change in Australia by 4–21% per annum.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This also is an example of the shrinking ability of the ocean to serve as a carbon sink because of global warming. And it shows that small changes in the ocean's CO&lt;sub&gt;2&lt;/sub&gt; concentration can make huge changes in the atmospheric concentration of CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorUserId="2470" LastEditDate="2020-04-12T05:48:59.430" LastActivityDate="2020-04-12T05:48:59.430" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19585" PostTypeId="1" CreationDate="2020-04-11T18:06:42.900" Score="1" ViewCount="43" Body="&lt;p&gt;In Diagram 1 of the following &quot;&lt;a href=&quot;https://www.ciwf.org.uk/media/5235024/The-life-of-laying-hens.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ciwf.org.uk/media/5235024/The-life-of-laying-hens.pdf&lt;/a&gt;&quot;, it explains how laying hens are produced. Realistically I imagine it's more complex than this simple flow chart. Are multiplication units used to produce other multiplication units? Or, do the multiplication units solely come from breeding chickens and solely produce laying hen?&lt;/p&gt;&#xA;" OwnerUserId="20281" LastActivityDate="2020-04-11T18:06:42.900" Title="Are laying hens used as multiplication units?" Tags="|agriculture|farm|" AnswerCount="0" CommentCount="3" ClosedDate="2020-04-12T13:25:45.397" ContentLicense="CC BY-SA 4.0" />
  <row Id="19586" PostTypeId="2" ParentId="19557" CreationDate="2020-04-11T19:16:47.413" Score="4" Body="&lt;p&gt;I think you are asking a question with a variety of different constraints. I'll tackle a couple of them.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What is the simplest atmospheric model to operate?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That would be the &lt;a href=&quot;https://math.nyu.edu/faculty/kleeman/zero_dim_ebm.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zero-dimensional energy balance model&lt;/a&gt;. It has almost zero resolution and no temporal capacity.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What is an atmospheric model that can be easily installed and run?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The &lt;a href=&quot;https://github.com/wrf-model/WRF&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weather Research and Forecasting (WRF) model&lt;/a&gt; is a very flexible, limited area model. &lt;a href=&quot;https://www.forbes.com/sites/marshallshepherd/2020/02/24/a-professor-ran-a-weather-prediction-model-on-a-50-computer/#43bfce0e5f65&quot; rel=&quot;nofollow noreferrer&quot;&gt;This model has successfully been run on what amounts to a child's toy.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;What is a global atmospheric model that can be run for a long period of time, but can easily be run?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;While I have never run it myself, it sounds like you may be looking for &lt;a href=&quot;https://www.ictp.it/research/esp/models/speedy.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;SPEEDY&lt;/a&gt;. I have not heard it is the most numerically stable model, and I cannot attest to how easy it is to run. From the documentation, it seems like it can be run one year at a time, but I was once told that it is typically stable in the range of months or even days.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Atmospheric models are not like a game you can just install and run like MS Word or a game. With almost any atmospheric model, a knowledge of programming in a Linux/Unix framework is paramount.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-04-11T19:16:47.413" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19587" PostTypeId="2" ParentId="9588" CreationDate="2020-04-11T22:35:05.573" Score="1" Body="&lt;p&gt;Warming climate conditions can cause carbon sinks, notably permafrost, to release carbon dioxide and that is in addition to the CO&lt;sub&gt;2&lt;/sub&gt; from fossil burning that induced the warming and causes additional warming as well, &lt;em&gt;so yes, climate change causes CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere to increase&lt;/em&gt;. This is an example of a carbon feedback or &lt;em&gt;&lt;a href=&quot;https://royalsocietypublishing.org/doi/10.1098/rsta.2017.0263&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth system feedback&lt;/a&gt;.&lt;/em&gt; Others include methane emissions from wetlands, where warming causes release of a greenhouse gas that makes warming stronger. There is also feed back that offsets warming, such as warming shortening the time for methane to break down.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What we do not have is any evidence of naturally occurring global warming sufficient to cause all or even most of the raised CO&lt;sub&gt;2&lt;/sub&gt; levels we are currently experiencing. Most of the CO&lt;sub&gt;2&lt;/sub&gt; rise is attributable to fossil fuel burning and land use changes, with an additional component from all forms of carbon feedback.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="2470" LastEditDate="2020-04-12T05:53:21.323" LastActivityDate="2020-04-12T05:53:21.323" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19588" PostTypeId="1" CreationDate="2020-04-12T18:47:00.323" Score="1" ViewCount="105" Body="&lt;p&gt;What is our current understanding between the ratio of Earth's interior heat between the downward pressure and atomic decay?&lt;/p&gt;&#xA;" OwnerUserId="20289" LastActivityDate="2020-04-13T11:07:49.413" Title="Earth's interior heat ratio between pressure and atomic decay" Tags="|geology|geothermal-heat|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19589" PostTypeId="2" ParentId="19588" CreationDate="2020-04-13T11:07:49.413" Score="1" Body="&lt;p&gt;There is no heat caused by pressure. Heat increases with depth, like pressure, so the two show a correlation, but this does not imply causality.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The two main sources of Earth's internal heat are radiogenic heat (as you said) and primordial heat, that is the kinetic energy turned into thermal energy during the accretion of the planet. There are also minor sources, like tidal heat caused by the Moon, and latent heat caused by crystallization of the liquid core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The total heat budget of the Earth is pretty well constrained: we can just measure the heat flow coming out at the surface (in W/m&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt;) and multiply this by the Earth's area. The current estimate is ~47 TW (&lt;a href=&quot;https://doi.org/10.5194/se-1-5-2010&quot; rel=&quot;nofollow noreferrer&quot;&gt;Davies &amp;amp; Davies, 2010&lt;/a&gt;). Getting ratios between sources, however, is more difficult, and rely mostly on modelling. See for instance the work of &lt;a href=&quot;https://doi.org/10.1029/2012RG000400&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dye (2012)&lt;/a&gt;, who proposed a radiogenic heating of 15–41 TW, while other authors (referenced by Dye) proposed 12–30 TW of primordial (&quot;fossil&quot;) heat. As you can see, the uncertainty is still quite high...&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-04-13T11:07:49.413" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19591" PostTypeId="2" ParentId="10149" CreationDate="2020-04-14T01:37:52.173" Score="1" Body="&lt;p&gt;Drumlins: elongated egg-shaped hills&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Kames: dumpling shaped hills&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Eskers: long sinuous hills, snake shaped&lt;/p&gt;&#xA;" OwnerUserId="20297" LastActivityDate="2020-04-14T01:37:52.173" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19592" PostTypeId="1" CreationDate="2020-04-14T17:23:38.300" Score="4" ViewCount="98" Body="&lt;p&gt;According to &lt;a href=&quot;https://en.wikipedia.org/wiki/Geography_of_the_Netherlands#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;*, April is the driest month in the Netherlands, with only 41.6mm rainfall on average, as opposed to neighbouring months March (57.8mm) and May (59.3mm). This difference (about 40% more) cannot be explained by the extra day; that's only about 3%. The same thing happens (I suppose) for Belgium; the &lt;a href=&quot;https://en.wikipedia.org/wiki/Brussels#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;monthly averages for Brussels&lt;/a&gt; are 69.5 (March), 51.3 (April) and 65.1 (May). April is also the driest month in &lt;a href=&quot;https://en.wikipedia.org/wiki/Luxembourg_City#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Luxembourg&lt;/a&gt; but not by that much.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;*: you have to click the 'show' link next to &lt;strong&gt;Climate data for De Bilt (1981–2010 averages), all KNMI locations (1901–2019 extremes), snowy days: (1971–2000 averages).&lt;/strong&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;While there must be a month in the year with the lowest rainfall, I wouldn't expect such a dip; all other months in the first half of the year are in the 60-70mm range (when February is adjusted for its short length). A possible reason for April to be the lowest is that sea and land temperatures are about equal, but somewhere in the fall that happens too, and that's the rainiest period of the year here.&lt;/p&gt;&#xA;&lt;p&gt;As for other areas in western Europe: for &lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_of_the_United_Kingdom#England&quot; rel=&quot;nofollow noreferrer&quot;&gt;England&lt;/a&gt;, April and May are about equal (56.1 vs 57.2). &lt;a href=&quot;https://en.wikipedia.org/wiki/Hamburg#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hamburg, Germany&lt;/a&gt; exhibits the same behaviour as the Benelux.&lt;/p&gt;&#xA;" OwnerUserId="2958" LastEditorUserId="2958" LastEditDate="2023-07-04T18:08:29.740" LastActivityDate="2023-07-04T18:24:21.213" Title="Why is April the driest month (by far) in the Benelux?" Tags="|climate|precipitation|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19593" PostTypeId="1" CreationDate="2020-04-14T19:05:57.920" Score="3" ViewCount="101" Body="&lt;p&gt;I am looking at Bernoulli's equation formulated in two dimensions, which reads&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{v^2}{2}+c_p\theta_0\pi+gz \equiv \mathrm{const.}$$&lt;/span&gt;&#xA;along a given streamline &lt;span class=&quot;math-container&quot;&gt;$\gamma$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$v=|\mathrm{v}|$&lt;/span&gt; for the flow field &lt;span class=&quot;math-container&quot;&gt;$\mathrm{v}(x,z)$&lt;/span&gt; which is in steady state (i.e. &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial\mathrm{v}}{\partial t}\equiv 0$&lt;/span&gt;) and &lt;span class=&quot;math-container&quot;&gt;$\pi=\left(\frac{p}{p_0}\right)^\frac{R}{c_p}$&lt;/span&gt; is the Exner function. The potential temperature &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; is assumed to be constant equal to &lt;span class=&quot;math-container&quot;&gt;$\theta_0$&lt;/span&gt; along &lt;span class=&quot;math-container&quot;&gt;$\gamma$&lt;/span&gt;. Now if we assume &lt;span class=&quot;math-container&quot;&gt;$\pi$&lt;/span&gt; to be constant along &lt;span class=&quot;math-container&quot;&gt;$\gamma$&lt;/span&gt; as well, we end up with an upper bound to the maximum upward displacement an air parcel with initial velocity &lt;span class=&quot;math-container&quot;&gt;$v_0$&lt;/span&gt; and initial height &lt;span class=&quot;math-container&quot;&gt;$z_0$&lt;/span&gt; can attain, namely&#xA;&lt;span class=&quot;math-container&quot;&gt;$$z_{crit}= z_0+\frac{v_0^2}{2g},$$&lt;/span&gt;&#xA;since &#xA;&lt;span class=&quot;math-container&quot;&gt;$$v^2=0 \text{ if and only if } z-z_0=\frac{v_0^2}{2g}.$$&lt;/span&gt;&#xA;But is the assumption that &lt;span class=&quot;math-container&quot;&gt;$\pi$&lt;/span&gt; is constant along &lt;span class=&quot;math-container&quot;&gt;$\gamma$&lt;/span&gt; a physically useful one? I cannot find a discussion concerning this in any textbook on meteorology I currently posses, neither in internet resources. Any advice/resource would be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="18370" LastActivityDate="2020-04-15T14:57:57.030" Title="Is it meaningful to assume static pressure to be constant along a streamline?" Tags="|meteorology|wind|fluid-dynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19594" PostTypeId="2" ParentId="19593" CreationDate="2020-04-15T03:33:17.090" Score="2" Body="&lt;p&gt;If you assume both hydrostatic and pure geostrophic balance, that is a valid assumption.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In Einstein notation, &lt;span class=&quot;math-container&quot;&gt;$$u_i=-\frac{1}{f \rho}\frac{\partial P}{\partial x_j}\epsilon_{ij3}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If we look at the equation for the streamline:&lt;span class=&quot;math-container&quot;&gt;$$u_i=-\frac{\partial \psi}{\partial x_j}\epsilon_{ij3}$$&lt;/span&gt;, then we can see that &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$-\frac{\partial \psi}{\partial x_j}\epsilon_{ij3}=-\frac{1}{f \rho}\frac{\partial P}{\partial x_j}\epsilon_{ij3}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;which simplifies down to &lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial \psi}{\partial x_j}=\frac{1}{f \rho}\frac{\partial P}{\partial x_j}$$&lt;/span&gt;. Thus, for isochoric (incompressible) geostrophic flow on an f-plane, the streamfunction only depends solely on pressure.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2020-04-15T14:57:57.030" LastActivityDate="2020-04-15T14:57:57.030" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19598" PostTypeId="1" AcceptedAnswerId="19599" CreationDate="2020-04-16T01:25:54.960" Score="1" ViewCount="84" Body="&lt;p&gt;By looking at the attenuation of cosmic ray muons passing through pyramids as a function of their direction, it seems it is possible to &quot;look inside&quot; by mapping their 3D density distributions.&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Washington Post: &lt;a href=&quot;https://www.washingtonpost.com/news/speaking-of-science/wp/2017/11/02/cosmic-rays-reveal-mysterious-void-in-egypts-great-pyramid/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cosmic rays reveal mysterious void in Egypt’s Great Pyramid&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Nature: &lt;a href=&quot;https://www.nature.com/news/cosmic-ray-particles-reveal-secret-chamber-in-egypt-s-great-pyramid-1.22939&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cosmic-ray particles reveal secret chamber in Egypt's Great Pyramid&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;arXiv: &lt;a href=&quot;https://arxiv.org/abs/1712.08590&quot; rel=&quot;nofollow noreferrer&quot;&gt;The secret chambers in the Chephren Pyramid&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Digital Trends: &lt;a href=&quot;https://www.digitaltrends.com/cool-tech/great-pyramid-muon-tomography/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Meet the tech that revealed a hidden chamber inside Egypt’s Great Pyramid&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Have cosmic ray muons or solar neutrinos been used to probe structures of the Earth, or to deduce or confirm any aspects of its structure in any way?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2020-04-16T01:32:42.983" LastActivityDate="2020-04-16T02:17:09.243" Title="Have cosmic ray muons or solar neutrinos been used to probe inside the Earth?" Tags="|earth-observation|structural-geology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19599" PostTypeId="2" ParentId="19598" CreationDate="2020-04-16T01:51:46.500" Score="1" Body="&lt;p&gt;In November 2008 &lt;a href=&quot;https://www.geographyrealm.com/measuring-the-neutrino-tomography-of-earth/&quot; rel=&quot;nofollow noreferrer&quot;&gt;neutrino tomography was used to measure Earth's mass&lt;/a&gt;. &lt;a href=&quot;https://arxiv.org/pdf/1803.05901.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;A paper&lt;/a&gt; was published in journal &lt;a href=&quot;https://www.nature.com/articles/s41567-018-0319-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nature&lt;/a&gt;. The data was &lt;a href=&quot;https://en.wikipedia.org/wiki/IceCube_Neutrino_Observatory&quot; rel=&quot;nofollow noreferrer&quot;&gt;captured by the South Pole’s&lt;/a&gt; &lt;a href=&quot;https://icecube.wisc.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;IceCube Neutrino Observatory&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In November 2013 IceCube announced it had discovered 28 neutrinos that likely originated outside the Solar System.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The neutrinos that the IceCube detector had “caught” came from different angles because they probed different layers of Earth. By measuring how many neutrinos came from different angles, the scientific team was able to measure the densities of various Earth’s segments, and from that – the total mass of Earth.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The neutrino tomography confirmed the traditional measurements on Earth’s mass, based on gravitational calculations and seismological data. That is especially interesting because neutrino tomography is a conceptually different and independent method – it doesn’t rely on gravity, but purely on weak interactions and the nucleon masses.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;While nothing new was discovered, the fact that a new technique has proven the old calculation right is exciting in its own terms.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Also, from the &lt;a href=&quot;https://www.ub.edu/web/ub/en/menu_eines/noticies/2018/11/009.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;University of Barcelona&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In 2006 there was a proposal with Harvard University to establish a network of ten detectors to enable &lt;a href=&quot;https://ui.adsabs.harvard.edu/abs/2006EM%26P...99..193D/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;tomography of the Earth via antineutrinos&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Not related to the question, but interesting. CERN has a proposal to &lt;a href=&quot;http://cms.cern/content/homeland-security&quot; rel=&quot;nofollow noreferrer&quot;&gt;detect nuclear contraband using cosmic ray muon tomography&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2020-04-16T02:17:09.243" LastActivityDate="2020-04-16T02:17:09.243" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19601" PostTypeId="1" AcceptedAnswerId="19602" CreationDate="2020-04-16T04:30:31.987" Score="2" ViewCount="2384" Body="&lt;p&gt;I've been reading about the Bergeron process, a process that generates much of the precipitation in the middle latitudes by generating ice crystals at the expense of water droplets. The part I don't understand is the supersaturation with respect to ice versus with respect to water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From Earth Science by Tarbuck, Lutgens, and Tasa:&#xA;&quot;When air is saturated with respect to water, it is supersaturated with respect to ice . . . Thus, ice crystals cannot coexist with water droplets because the air always 'appears' supersaturated to the ice crystals. Hence, the ice crystals begin to consume the 'excess' water vapor . . .&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't exactly understand what supersaturation relative to water and ice mean, even though they've attempted to explain it. My first thought is that maybe on the ice surface, the affinity for water vapor molecules is higher than in air, so water vapor molecules are more likely to be deposited on the surface, hence why the relative humidity with respect to the ice is higher. However, in my thinking, &quot;with respect to&quot; would mean which surface the water vapor is getting deposited on, when clearly the statement says the thing being deposited (&quot;with respect to water&quot;). Can someone explain this clearly for me?&lt;/p&gt;&#xA;" OwnerUserId="20309" LastActivityDate="2020-04-17T23:00:11.057" Title="What does supersaturation with respect to ice mean?" Tags="|precipitation|humidity|water-vapour|" AnswerCount="2" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19602" PostTypeId="2" ParentId="19601" CreationDate="2020-04-16T08:17:49.513" Score="2" Body="&lt;p&gt;The &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Saturation_vapor_pressure&quot; rel=&quot;nofollow noreferrer&quot;&gt;saturation vapour pressure&lt;/a&gt; defined by the American Meteorological Society:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The vapor pressure of a system, at a given temperature, for which the vapor of a substance is in equilibrium with a plane surface of that substance's pure liquid or solid phase; that is, the vapor pressure of a system that has attained saturation but not supersaturation.&lt;/p&gt;&#xA;&lt;p&gt;The saturation vapor pressure of any pure substance, with respect to a specified parent phase, is an intrinsic property of that substance, and is a function of temperature alone. For water vapor, the saturation pressure over supercooled liquid differs appreciably from that over ice.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;When water vapour exists over a body of supercooled liquid water, water is constantly exchanged between the liquid form and the water vapour form.  When this reaches equilibrium, there is equal phase change in both directions.  If the air becomes saturated, no more water vapour can be added to it, for it will condensate to the liquid form immediately.  At this temperature, the vapour pressure is the saturation vapour pressure with respect to water.  Remember that water can exist well below 0°C — clouds are typically not completely frozen until temperatures drop to around -40°C, although it depends on many factors and the details are subject to ongoing research.&lt;/p&gt;&#xA;&lt;p&gt;When water vapour exists over a body of ice, there is a phase exchange.  At a certain temperature and pressure, the air is saturated, any water added will precipitate as ice.  At this temperature, the vapour pressure is the saturation vapour pressure with respect to ice.&lt;/p&gt;&#xA;&lt;p&gt;By &amp;quot;Body of&amp;quot; you should probably not so much think of a frozen lake or liquid ocean but rather of small cloud droplets or ice particles.&lt;/p&gt;&#xA;&lt;p&gt;This graph from Vermont State College shows the saturation vapour pressure over water or ice:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9xzTF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9xzTF.png&quot; alt=&quot;Saturation vapour pressure&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;em&gt;Source: &lt;a href=&quot;http://apollo.lsc.vsc.edu/classes/met130/notes/chapter7/eswgtesi.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Vermont State College&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;As your source stated, this difference is important for meteorology as it affects the formation of clouds and precipitation.&lt;/p&gt;&#xA;&lt;p&gt;Now as to &lt;strong&gt;why&lt;/strong&gt; the saturation vapour pressure is different with respect to water than with respect to ice is another question.  You may find more expertise for that on Chemistry Stack Exchange than here on Earth Science.  My atmospheric science textbooks in any case don't go into detail there.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-04-16T08:25:18.550" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19603" PostTypeId="1" CreationDate="2020-04-16T10:23:15.320" Score="3" ViewCount="156" Body="&lt;p&gt;Is there a meridian that has exactly as much emerged land area 180° on its East than 180° on its West (on the assumption that it could exist...)? If there is no meridian, is there any other great circle with that property?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: Since David Hammen proved that such a median exists, which one is it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And what is the latitude that has as much emerged land on its North than on its South (that one necessarily exists)? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I found this &lt;a href=&quot;https://en.wikipedia.org/wiki/Hemispheres_of_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia article&lt;/a&gt; but it doesn't really answers the question.&lt;/p&gt;&#xA;" OwnerUserId="20310" LastEditorUserId="20310" LastEditDate="2020-04-16T17:41:07.940" LastActivityDate="2020-04-16T17:41:07.940" Title="Splitting the Earth's emerged land in two equal parts" Tags="|geography|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="19604" PostTypeId="2" ParentId="19603" CreationDate="2020-04-16T16:51:33.567" Score="2" Body="&lt;p&gt;TL;DR: It depends on how one defines land area. With a sensible definition, such a meridian (along with its completion on the other side of the globe) must necessarily exist by virtue of the intermediate value theorem. The same goes for the line of latitude.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Defining the functions&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\operatorname{A}_{\text{E}}(\lambda)$&lt;/span&gt; is the area of the land projected onto the reference ellipsoid of the hemisphere to the east of the line of longitude &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\operatorname{A}_{\text{W}}(\lambda)$&lt;/span&gt; is the area of the land projected onto the reference ellipsoid of the hemisphere to the west of the line of longitude &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\operatorname{\Delta A}_{\text{lon}}(\lambda)$&lt;/span&gt; is the difference between &lt;span class=&quot;math-container&quot;&gt;$\operatorname{A}_{\text{E}}(\lambda)$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\operatorname{A}_{\text{W}}(\lambda)$&lt;/span&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\operatorname{A}_{\text{N}}(\phi)$&lt;/span&gt; is the area of the land projected onto the reference ellipsoid of the hemisphere to the north of the line of latitude &lt;span class=&quot;math-container&quot;&gt;$\phi$&lt;/span&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\operatorname{A}_{\text{S}}(\phi)$&lt;/span&gt; is the area of the land projected onto the reference ellipsoid of the hemisphere to the west of the line of longitude &lt;span class=&quot;math-container&quot;&gt;$\phi$&lt;/span&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\operatorname{\Delta A}_{\text{lat}}(\phi)$&lt;/span&gt; is the difference between &lt;span class=&quot;math-container&quot;&gt;$\operatorname{A}_{\text{N}}(\phi)$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\operatorname{A}_{\text{S}}(\phi)$&lt;/span&gt;.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;My definitions make each of these functions continuous. Note well: Other definitions of land area might result in non-continuous functions. Imagine a perfectly vertical cliff that runs north to south. If the area of that cliff face counted as land area then &lt;span class=&quot;math-container&quot;&gt;$\operatorname{\Delta A}_{\text{lon}}(\lambda)$&lt;/span&gt; will not be continuous. The same goes for &lt;span class=&quot;math-container&quot;&gt;$\operatorname{\Delta A}_{\text{lat}}(\phi)$&lt;/span&gt; for a perfectly vertical cliff that run east to west.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Proving that the latitude line must exist is easy, so I'll do that first. All of the Earth's land area is north of 90° south latitude, making &lt;span class=&quot;math-container&quot;&gt;$\operatorname{\Delta A}_{\text{lat}}(-90)$&lt;/span&gt; a large positive number. All of the Earth's land area is south of 90° north latitude, making &lt;span class=&quot;math-container&quot;&gt;$\operatorname{\Delta A}_{\text{lat}}(90)$&lt;/span&gt; a large negative number. Because zero is between this large negative number and large positive number, and because &lt;span class=&quot;math-container&quot;&gt;$\operatorname{\Delta A}_{\text{lat}}(\phi)$&lt;/span&gt; is continuous, there must necessarily exist at least one line of latitude &lt;span class=&quot;math-container&quot;&gt;$\phi$&lt;/span&gt; for which &lt;span class=&quot;math-container&quot;&gt;$\operatorname{\Delta A}_{\text{lat}}(\phi)$&lt;/span&gt; is zero.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Regarding longitude, Pick an arbitrary longitude &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt;. If &lt;span class=&quot;math-container&quot;&gt;$\operatorname{\Delta A}_{\text{lon}}(\lambda)$&lt;/span&gt; is zero we have a winner. If it's not zero, then since &lt;span class=&quot;math-container&quot;&gt;$\operatorname{\Delta A}_{\text{lon}}(\lambda +180°) = -\operatorname{\Delta A}_{\text{lon}}(\lambda)$&lt;/span&gt;, there exists at least one longitude &lt;span class=&quot;math-container&quot;&gt;$\lambda_0$&lt;/span&gt; between &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\lambda+180°$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$\operatorname{\Delta A}_{\text{lon}}(\lambda_0)$&lt;/span&gt; is zero.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-04-16T16:51:33.567" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19605" PostTypeId="1" CreationDate="2020-04-16T23:00:24.850" Score="6" ViewCount="104" Body="&lt;p&gt;So, I understand that during much of the year, Panama gets regular rain due to moist air being carried in by the trade winds from the Caribbean. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, the country also has a &quot;dry season&quot; from roughly December to March, and I haven't been able to find information on why that happens, given that the trade winds are supposed to be blowing year-round. Is there some climatic process in the Caribbean that weakens them or directs them northwards during this time of the year? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;EDIT: Ah, this must be related to the seasonal movement of the intertropical convergence zone, right? Is that that the trade wind effect is present year round, but just doesn't produce a lot of precipitation in Panama on its own, until the ITCZ adds majorly to it during the northern summer?&lt;/p&gt;&#xA;" OwnerUserId="20315" LastEditorUserId="20315" LastEditDate="2020-04-16T23:10:54.283" LastActivityDate="2020-04-16T23:10:54.283" Title="Why does Panama have a dry season?" Tags="|meteorology|climate|precipitation|climatology|seasons|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19606" PostTypeId="2" ParentId="15083" CreationDate="2020-04-17T10:13:42.977" Score="1" Body="&lt;p&gt;Although the temperature and climatic conditions for the formation of laterite as well as peaty soil is same but what causes variation in their humus content is high humidity and a thick vegetation cover (in particular fauna) present in peaty soil.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;A thick vegetation of fauna will eventually increase the accumulation of a large dead organic matter, hence giving a rich humus and organic content to the peaty soil.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Humidity refers to the addition of water molecules in the atmosphere. As temperature increases, humidity also increases, which eventually gives rise to bacteria and fungi, that thrives well in high temperature. These microorganisms will further increase the humus content through the process of decomposition.&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="20319" LastEditorUserId="6016" LastEditDate="2020-04-17T18:36:19.543" LastActivityDate="2020-04-17T18:36:19.543" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19608" PostTypeId="1" AcceptedAnswerId="19613" CreationDate="2020-04-17T22:42:35.193" Score="3" ViewCount="75" Body="&lt;p&gt;I am trying to make sure I have done my due diligence in researching the literature when it comes to a particular topic in oceanography and/or atmospheric science.  My specialization is in a different subject altogether, where we have one website in particular that has a collection of abstracts and titles for nearly all papers that have ever been published (pre- and post-internet era) in this particular area.  Those of us in the field can search the one website for certain keywords, and once you have done this with some variations on said keywords and then combed the relevant citing/cited literature, it's pretty safe to say you've done your due diligence to comb the literature.  Is there a similar website for the areas of oceanography and/or atmospheric science or does one usually use Google Scholar?  Any help would be much appreciated, thanks!&lt;/p&gt;&#xA;" OwnerUserId="20322" LastActivityDate="2020-04-18T15:01:42.667" Title="Soft Question: How Best to Thoroughly Exhaust the Literature" Tags="|literature-request|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19609" PostTypeId="2" ParentId="19601" CreationDate="2020-04-17T22:53:13.000" Score="2" Body="&lt;p&gt;I can identify two parts of how this may be confusing. The first is vapor pressure with respect to ice, and the second is supersaturation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;First, let's look over the equation for phase transitions. The saturation vapor pressure can be described by the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Clausius-clapeyron_equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Clausius Clapeyeron equation&lt;/a&gt;. Solving that equation explicitly (i.e. not using Bolton's formula used in the link), we find that &lt;span class=&quot;math-container&quot;&gt;$$e_s(T)=e_s(T_0)\exp(\frac{L}{R_v}[\frac{1}{T_0}-\frac{1}{T}])$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$e_s$&lt;/span&gt; is the saturation vapor pressure, &lt;span class=&quot;math-container&quot;&gt;$T_0$&lt;/span&gt; is a given temperature (usually 273 K), &lt;span class=&quot;math-container&quot;&gt;$L$&lt;/span&gt; is the latent heat of transformation, and &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; is temperature. Note that I said latent heat of transformation, so it could be from one phase to another. Thus we can make a phase space diagram shown below using &lt;span class=&quot;math-container&quot;&gt;$L_f$&lt;/span&gt; (latent heat of fusion), &lt;span class=&quot;math-container&quot;&gt;$L_v$&lt;/span&gt; (latent heat of vaporization), and &lt;span class=&quot;math-container&quot;&gt;$L_s$&lt;/span&gt; (latent heat of sublimation, gas to solid). The values for these can be found &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Latent_heat&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/p6ZdY.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/p6ZdY.png&quot; alt=&quot;Phase diagram&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where all three meet is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Triple_point&quot; rel=&quot;nofollow noreferrer&quot;&gt;triple point&lt;/a&gt;, but is more commonly referred to as the freezing temperature of water. Notice that the below it is where the liquid does not exist. Instead the gas goes directly into solid (&lt;a href=&quot;https://en.wikipedia.org/wiki/Deposition_(phase_transition)&quot; rel=&quot;nofollow noreferrer&quot;&gt;deposition&lt;/a&gt;). In reality, liquid water can exist below this temperature (&lt;a href=&quot;https://en.wikipedia.org/wiki/Supercooling&quot; rel=&quot;nofollow noreferrer&quot;&gt;supercooled water&lt;/a&gt;), but it will eventually turn into a gas or ice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I made a graph (below), similar to the phase diagram above, but does not clip off the clausius clapeyeron curve. Notice that below 273 K, the saturation pressure of vapor w.r.t. (with respect to) ice is lower than water. This basically says that it will first turn into ice before it turns into water. Then, above 273 K, the vapor saturation curve wrt water is less than ice- meaning it is easier to turn into liquid water above 273 K than it is for ice.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/88wqR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/88wqR.png&quot; alt=&quot; Custom Clausius Clapeyeron curve&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Next is the concept of supersaturation. Supersaturation generically refers to a state that is above saturation. In this sense, supersaturation can be identified by having a relative humidity over 100%. While some websites may give a different definition, I think of relative humidity as being the ratio of water entering the liquid (or solid phase), to water becoming a gas. So supersaturation means that there is enough water vapor in the air, at that temperature, to form a cloud.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I should note, that the process of making a cloud can be a bit more convoluted than this answer. For that, I recommend looking at &lt;a href=&quot;https://earthscience.stackexchange.com/questions/5047/at-what-humidity-does-it-start-to-rain/5048#5048&quot;&gt;this answer&lt;/a&gt; where I discuss &lt;a href=&quot;https://en.wikipedia.org/wiki/K%C3%B6hler_theory&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kohler theory&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the short answer is, there is sufficient water vapor in the air to form a cloud.  But because it is below freezing, the cloud is formed via deposition, much like how &lt;a href=&quot;https://en.wikipedia.org/wiki/Frost&quot; rel=&quot;nofollow noreferrer&quot;&gt;frost&lt;/a&gt; is formed.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2020-04-17T23:00:11.057" LastActivityDate="2020-04-17T23:00:11.057" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19610" PostTypeId="1" CreationDate="2020-04-18T06:40:57.543" Score="2" ViewCount="149" Body="&lt;p&gt;It does not &lt;a href=&quot;https://aqicn.org/city/paris/&quot; rel=&quot;nofollow noreferrer&quot;&gt;seem&lt;/a&gt; that the air pollution level is getting any lower in Paris during the current shutdown due to COVID-19.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Why is that?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are fewer cars. Are they only a small part of Paris' air pollution?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Where is the pollution coming from? &lt;/p&gt;&#xA;" OwnerUserId="20323" LastEditorUserId="725" LastEditDate="2020-04-28T04:42:54.590" LastActivityDate="2020-05-01T20:05:02.323" Title="Why is Paris still polluted during the Covid-19 shutdown?" Tags="|climate|air-pollution|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19611" PostTypeId="2" ParentId="19608" CreationDate="2020-04-18T07:05:49.467" Score="1" Body="&lt;p&gt;I would suggest combing &lt;strong&gt;Google Scholar&lt;/strong&gt; with the following methods:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Search keywords just as you've mentioned.   &lt;/li&gt;&#xA;&lt;li&gt;When you hit on a semi-relevant paper, check the citations for relevant information.&lt;/li&gt;&#xA;&lt;li&gt;Additionally check the collected works of the authors of said papers.  &lt;/li&gt;&#xA;&lt;li&gt;Search specifically for review papers or graduate-level textbooks for context on a subject and more citations.  &lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;The perk of interdisciplinary Earth Science is that everything connects.  The downside of interdisciplinary Earth Science is that information is dispersed.  Good luck.&lt;/p&gt;&#xA;" OwnerUserId="20324" LastActivityDate="2020-04-18T07:05:49.467" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19613" PostTypeId="2" ParentId="19608" CreationDate="2020-04-18T15:01:42.667" Score="1" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;...one website in particular that has a collection of abstracts and titles for nearly all papers that have ever been published (pre- and post-internet era) in this particular area.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;For as long as I can remember (okay, since 2002) the standard source of this type has been the &lt;a href=&quot;https://webofknowledge.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Web of Science&lt;/a&gt;.  It covers all sciences (and engineering, social science) so you have to restrict your search with sensible combinations of keywords, categories, and journal names, but it's the closest thing to a neutral database that we have.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't find Google Scholar to be a good substitute.  It doesn't have a very good signal to noise, you'll often get multiple hits to entries of the same article in different databases, but direct links to the actual journal article can appear quite low down on the list.  I know this has been a problem for EGU/Copernicus journal articles, which appear much lower down than social network (e.g., ResearchGate) links.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The problem with both of those tools though is the sheer volume of articles.  So much is published these days that it's simply not possible for anyone to exhaust the search.  My lab often recruits post-docs into Earth science positions from other disciplines (e.g., maths, physics) and knowing where to start or finish with the literature can be intimidating for them.  What they need is for some experienced researchers in the field to filter the literature for them, which is why I normally recommend reading recent &lt;em&gt;review articles&lt;/em&gt; as a way of gauging the knowledge boundaries.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are journals dedicated to review articles, e.g.,&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.sciencedirect.com/journal/earth-science-reviews&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth Science Reviews&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/journal/19449208&quot; rel=&quot;nofollow noreferrer&quot;&gt;Review of Geophysics&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.nature.com/natrevearthenviron&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nature Reviews Earth &amp;amp; Environment&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://encyclopedia-of-geosciences.net/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Encyclopedia of Geosciences&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;and doubtlessly there are more than I've forgotten.  Some publishers also curate collections of important articles from across their journals, e.g.,&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.nature.com/collections/bfihgidbhc&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nature Collections&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/toc/10.1002/(ISSN)1944-9208.GRANDCHAL1&quot; rel=&quot;nofollow noreferrer&quot;&gt;AGU Grand Challenges&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Read the references you find in those and maybe go one level deeper and then you'll have done your due diligence.  I still stumble across seams of papers I've missed in fields that I've worked in for years and it's never been a problem; no one expects you to be exhaustive in your search.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2020-04-18T15:01:42.667" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19614" PostTypeId="1" AcceptedAnswerId="19615" CreationDate="2020-04-18T15:17:56.297" Score="1" ViewCount="511" Body="&lt;p&gt;You have object A of hardness 4 and glass B of hardness 6.&#xA;Is this information alone enough to determine that, under any circumstances object A will never be able to scratch glass B?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For a more practical example, does this mean that it doesn't matter how hard you press, how fine the point of the object is, how long you keep scratching on B's surface, etc. a cat claw for example will never leave a scratch on a hardness 5 phone glass?&#xA;Or is it just like un-noticeable/negligible?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This doesn't seem to make sense on an atomic scale, since both A and B should be losing loose atoms from their interaction.&lt;/p&gt;&#xA;" OwnerUserId="20326" LastActivityDate="2020-04-20T21:43:36.227" Title="Does higher hardness means that A cannot scratch B regardless of any other variable?" Tags="|mineralogy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19615" PostTypeId="2" ParentId="19614" CreationDate="2020-04-18T16:06:46.687" Score="2" Body="&lt;p&gt;Welcome.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You're referring to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardness&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mohs hardness scale&lt;/a&gt;, a qualitative scale to quickly determine, in the field, whether something scratches (carves a mark into) something else. It states nothing about the opposite direction. Of course, given enough pressure or kinetic energy the scraper can experience deformation as well, but that's not the meaning of the exercise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;One can pretty well scratch Gypsum with the finger nail and feldspar with a steel nail. You don't hammer things and do not scratch over and again or with more force than necessary. It's more like, for instance, cutting wood with a pocket knife. No molecules are counted and no microscopic traces investigated, it is just a superficial visual inspection for use in the field. Laboratory work comes later.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://geology.com/minerals/mohs-hardness-scale.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://geology.com/minerals/mohs-hardness-scale.shtml&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardness&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Mohs_scale_of_mineral_hardness&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nps.gov/articles/mohs-hardness-scale.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nps.gov/articles/mohs-hardness-scale.htm&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Edit: To make some sciency disport out of this, &lt;a href=&quot;https://blogs.plos.org/everyone/2013/09/20/the-power-of-the-claw-not-your-average-soft-material/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here's a work&lt;/a&gt; that deals with the force of a large cat's claws and muscles against the bones of its prey.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even though the claw, being made of keratin (same as horn, hoove, nail, ...), only has a Mohs hardness of 2.5, it can do considerable damage to a bone of hardness 5. That's because of the kinetic energy induced by the sweep of a paw and the chain of muscles at whose end it sits.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The field test based on Mohs hardness is not affected by the application of kinetic energy.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-04-20T21:43:36.227" LastActivityDate="2020-04-20T21:43:36.227" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19617" PostTypeId="1" AcceptedAnswerId="19618" CreationDate="2020-04-18T18:22:56.680" Score="1" ViewCount="59" Body="&lt;p&gt;Bear with me if this is a wrong place to ask this question. I aksed this question on Physics at StackExchange and was told it will be more on topic here.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recent news show a fire has started close to the former nuclear plant in Chernobyl because someone was burning grass. Ukrainian State Scientific and Technical Center for Nuclear and Radiation Safety &lt;a href=&quot;https://sstc.ua/news/rozrahunkovi-trayektoriyi-rozpovsyudzhennya-potencijno-zabrudnenogo-povitrya-na-osnovi-onovlenih-danih&quot; rel=&quot;nofollow noreferrer&quot;&gt;explained&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;the fire in the exclusion zone has been extinguished. [...] The updated modeling results indicate that the potential maximum concentrations of Cs-137 in the surface layer in Kyiv were lower than 0.1 mBq/m3. The forecasted concentrations are less than those observed previously and more than 1000 times lower than the acceptable levels established by NRBU-97. They do not pose any harm to the health of the population.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The information has been &lt;a href=&quot;https://www.paa.gov.pl/aktualnosc-546-komunikat_paa_w_zwiazku_z_pojawiajacymi.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;confirmed&lt;/a&gt; (translation mine) by Polish National Atomic Energy Agency:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;With regard to false information appearing in public space about the alleged occurrence of radioactive contamination in Poland, the National Atomic Energy Agency strongly denies this type of information. The radiation situation in the territory of the Republic of Poland remains normal. There is no threat to the health and life of the population in the country.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;On the other hand, we have received contradicting information from several friends, family and &quot;trusted&quot; sources that there was a threat to our safety and we should stay at home for two days and close the doors and windows to avoid contamination. I consider this fake news, but I am also aware that sometimes governmental agencies delay notifying the public because of political or other reasons. For instance, when there was Chernobyl disaster in 1986, some scientist at one of Polish physics institute had access to Geiger counter. They started to carry over their own measurements of contamination but they were told to stop doing that by the institute authorities that there connected to the Communist Party at that time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There used to be a similar problem with smog air pollution in my and other European countries. There were some governmental measurements of air pollution but there was also some controversy how they measured air pollution, how frequently they reported it and how they defined safety thresholds. In a response to that problem multiple companies started to produce low-cost devices that you can install at your home to measure air pollution. This provides a source of information independent from governmental agencies.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there similar initiative, agencies, companies, etc. that measure radiation pollution in Europe?&lt;/p&gt;&#xA;" OwnerUserId="20328" LastEditorUserId="20328" LastEditDate="2020-04-18T18:48:40.180" LastActivityDate="2020-04-18T20:22:56.177" Title="Independent sources of information on radiation pollution in Europe" Tags="|air-pollution|pollution|radioactivity|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19618" PostTypeId="2" ParentId="19617" CreationDate="2020-04-18T20:11:21.387" Score="1" Body="&lt;p&gt;Two websites I've come across that might be of interest are:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://remon.jrc.ec.europa.eu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Radioactivity Environmental Monitoring Joint Research Centre&lt;/a&gt;, for Europe.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://radmon.org/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Radmon.org&lt;/a&gt; which provides radiation information from number of&#xA;global station.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2020-04-18T20:22:56.177" LastActivityDate="2020-04-18T20:22:56.177" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19620" PostTypeId="2" ParentId="8806" CreationDate="2020-04-19T23:46:07.233" Score="0" Body="&lt;p&gt;The Salt Fork of the Arkansas River in Oklahoma and the Dirty Devil River in Utah are two more rivers which have considerable salinity,&lt;/p&gt;&#xA;" OwnerUserId="20333" LastActivityDate="2020-04-19T23:46:07.233" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19621" PostTypeId="2" ParentId="18986" CreationDate="2020-04-20T02:53:34.757" Score="0" Body="&lt;p&gt;I would like to address what appears to be an over-generalization of your premise.  You seem to be simplifying the radiative heat from the Earth.  Yes, if you take an average temperature and an average atmosphere, the present amount of CO2 is almost completely maxing out the sides of the absorption bands and an increase in CO2 gets you almost no additional absorption.  However, that is an average.  Keep in mind that the majority of warming that is currently happening is at high latitudes and high altitudes, where infrared from the Earth is far below average.  The increase in global CO2 has a larger affect in these colder regions because there is greater sensitivity to the increase in CO2, affecting those fringes of the absorption bands. &lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2020-04-20T02:53:34.757" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19622" PostTypeId="1" AcceptedAnswerId="19650" CreationDate="2020-04-20T13:49:46.337" Score="5" ViewCount="99" Body="&lt;p&gt;So according to this,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.drroyspencer.com/2020/04/uah-global-temperature-update-for-march-2020-0-48-deg-c/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global temperature update&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Last month, the lower tropospheric temperature dropped 0.28 &lt;span class=&quot;math-container&quot;&gt;$\sf^\circ$&lt;/span&gt;C from February to March, which seems like a huge drop even if it's due to seasonal reasons.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A former NASA employee in that link conjectures it's not related to Coronavirus reduced CO&lt;sub&gt;2&lt;/sub&gt; emissions, but it might be related to Coronavirus reduced jet contrails.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is, is lower tropospheric temperature relevant to measuring global warming? Is there a relationship between lower tropospheric temperature and land-ocean level temperature, that seems to be the temperature we care about when measuring the impact on life on the planet? &lt;/p&gt;&#xA;" OwnerUserId="9635" LastEditorUserId="9635" LastEditDate="2020-04-20T16:39:44.300" LastActivityDate="2020-04-29T13:16:12.887" Title="Is lower tropospheric temperature relevant to measure global warming?" Tags="|climate-change|temperature|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19624" PostTypeId="1" AcceptedAnswerId="19629" CreationDate="2020-04-20T20:55:38.020" Score="2" ViewCount="81" Body="&lt;p&gt;I am a physics graduate and trying to understand one of the assumptions made for isochron dating of rocks: at crystallization time of the rock, &lt;span class=&quot;math-container&quot;&gt;$t=0$&lt;/span&gt;, the ratio of the parent isotope to a stable reference daughter isotope was variable for different parts/minerals of the rock (&lt;span class=&quot;math-container&quot;&gt;$P/D_{ref}\neq const$&lt;/span&gt;), but the ratio of the radiogenic daughter isotope to the stable reference daughter isotope was constant (&lt;span class=&quot;math-container&quot;&gt;$D*/D_{ref}=const$&lt;/span&gt;). See for that the figure below taken from &lt;a href=&quot;https://en.wikipedia.org/wiki/Isochron_dating&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; :&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ozIdg.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ozIdg.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question: &lt;strong&gt;Why is the one ratio constant, but the other not?&lt;/strong&gt; I taught &lt;span class=&quot;math-container&quot;&gt;$D*/D_{ref}=const$&lt;/span&gt; holds, because just before &lt;span class=&quot;math-container&quot;&gt;$t=0$&lt;/span&gt; the rock is still molten and components are well mixed, but then why shouldn't &lt;span class=&quot;math-container&quot;&gt;$P$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$D_{ref}$&lt;/span&gt; be also homogeneously mixed and uniformly distributed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Additional question: In the figure below, taken from &lt;a href=&quot;https://debunkingdenialism.com/2011/08/12/refuting-radiometric-dating-methods-makes-untenable-assumptions/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, I get that the linear function is the isochron, but what is the logarithmic function and how does it help in the dating process/what is its contribution? Thanks&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8NEMD.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8NEMD.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20337" LastActivityDate="2020-04-22T08:37:01.600" Title="In radiometric isochron dating why is at t=0 D*/Dref=const but P/Dref not?" Tags="|rocks|dating|radioactivity|isotopic|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19625" PostTypeId="2" ParentId="18986" CreationDate="2020-04-21T01:20:18.080" Score="0" Body="&lt;p&gt;A complimentary article to the one written by Spencer Weart and recommended by Dikran Marsupial is this other article from September 2019 written by Jason West, Professor of Environmental Sciences and Engineering, University of North Carolina at Chapel Hill.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://theconversation.com/climate-explained-why-carbon-dioxide-has-such-outsized-influence-on-earths-climate-123064&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate explained: why carbon dioxide has such outsized influence on Earth’s climate&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It underpins what has been said here that what matters most is the height that the carbon dioxide layer can reach at the upper atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;In the article is said that carbon dioxide is important for climate despite the fact that water vapor absorbs more infrared radiation and the two gases absorb at several of the same wavelengths.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The reason is that Earth’s upper atmosphere controls the radiation that escapes to space. The upper atmosphere is much less dense and contains much less water vapor than near the ground, which means that adding more carbon dioxide significantly influences how much infrared radiation escapes to space.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The article also re-states information given by by Spencer Weart about the role of carbon dioxide in climate change:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The scientists who first identified carbon dioxide’s importance for climate in the 1850s were also surprised by its influence. Working separately, John Tyndall in England and Eunice Foote in the United States found that carbon dioxide, water vapor and methane all absorbed heat, while more abundant gases did not.&lt;/p&gt;&#xA;&lt;p&gt;Tyndall and Foote showed that nitrogen and oxygen, which together account for 99% of the atmosphere, had essentially no influence on Earth’s temperature because they did not absorb heat. Rather, they found that gases present in much smaller concentrations were entirely responsible for maintaining temperatures that made the Earth habitable, by trapping heat to create a natural greenhouse effect.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The reason why carbon dioxide has a much more importance in warming the planet while much more abundant gases like nitrogen and oxygen do not play an important role is related to its molecular structure:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Carbon dioxide and other heat-trapping gases have molecular structures that enable them to absorb infrared radiation. Carbon dioxide and other heat-trapping gases have three or more atoms and frequencies that correspond to infrared radiation emitted by Earth. Oxygen and nitrogen, with just two atoms in their molecules, do not absorb infrared radiation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The article provides important pre-historic information about the concentration of carbon dioxide in the atmosphere and its correlation with the concentration of water vapor in the atmosphere and the consequences for the climate.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The influence of carbon dioxide can be seen in past changes in climate. Ice cores from over the past million years have shown that carbon dioxide concentrations were high during warm periods – about 0.028%. During ice ages, when the Earth was roughly 7 to 13 F (4-7 C) cooler than in the 20th century, carbon dioxide made up only about 0.018% of the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;Even though water vapor is more important for the natural greenhouse effect, changes in carbon dioxide have driven past temperature changes. In contrast, water vapor levels in the atmosphere respond to temperature. As Earth becomes warmer, its atmosphere can hold more water vapor, which amplifies the initial warming in a process called the “water vapor feedback.” Variations in carbon dioxide have therefore been the controlling influence on past climate changes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It finishes explaining why it is foolhardy not to diminish the carbon dioxide emissions to prevent big effect on Earths climate:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Today the level of carbon dioxide is higher than at any time in human history. Scientists widely agree that Earth’s average surface temperature has already increased by about 2 F (1 C) since the 1880s, and that human-caused increases in carbon dioxide and other heat-trapping gases are extremely likely to be responsible.&lt;/p&gt;&#xA;&lt;p&gt;Without action to control emissions, carbon dioxide might reach 0.1% of the atmosphere by 2100, more than triple the level before the Industrial Revolution. This would be a faster change than transitions in Earth’s past that had huge consequences. Without action, this little sliver of the atmosphere will cause big problems.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FG0xN.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FG0xN.png&quot; alt=&quot;Carbon dioxide concentration in the atmosphere from 1958 to 2019&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20335" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-04-21T01:20:18.080" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19626" PostTypeId="2" ParentId="4769" CreationDate="2020-04-21T05:29:06.003" Score="-1" Body="&lt;p&gt;Lava pushes the plates apart at midocean ridges with 5000 bars. This is how mountains are built. Slab pull and gravity ridge push cannot build the observed mountains. In addition, they cannot drive tectonics, externally energy is required. &lt;/p&gt;&#xA;" OwnerUserId="20340" LastActivityDate="2020-04-21T05:29:06.003" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19628" PostTypeId="2" ParentId="7244" CreationDate="2020-04-21T19:21:59.693" Score="0" Body="&lt;p&gt;I was looking at this as well.  It looks to me like a sedimentary formation created from the southerly flows potentially off the glaciers in the north at the end of the younger dryas. Follow the St.Lawrence seaway and look at the shape of the Adirondacks, its almost like an island formed in a torrent of waters suddenly released.  There was a recent find in Greenland of a large impact on the ice sheet called Hiawatha. If that was the case I would postulate that sudden melt-flows would careen down the left side of the Appalachian mountains along with an incredible amount of debris and sediment.  At some point it would have found a delta area or created a debris mount that might create a sedimentary lake.  It shows in the natural geology to have a sharp incline on one side and a gradual one to the north.  This would line up with a depositing location along an older impact crater, mountain rise or sweep in the natural geology of the area. It looks HUGE. &lt;/p&gt;&#xA;" OwnerUserId="20346" LastActivityDate="2020-04-21T19:21:59.693" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19629" PostTypeId="2" ParentId="19624" CreationDate="2020-04-22T07:07:01.920" Score="5" Body="&lt;p&gt;1) D* (radiogenic isotope) and D&lt;sub&gt;ref&lt;/sub&gt; (stable reference isotope) are two isotopes of the same element. P is the radioactive parent of D*, and is a different element. Chemical fractionation between P and D&lt;sub&gt;ref&lt;/sub&gt; occurs as the rock solidifies because different elements are preferentially incorporated in different minerals depending on how well their ionic radii and valences are compatible with the mineral's crystalline lattice. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Although there can be some mass-fractionation of isotopes of a same element, it is usually very small (IE negligible) relative to the chemical fractionation.&#xA;Often, for making such isochrons, geologists choose different mineral species with very different P concentrations (and thus varying P/D&lt;sub&gt;ref&lt;/sub&gt;) to provide spread along the isochron line; this allows for more precise regression and determination of the slope / age.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) The second diagram you show is a concordia plot, not an isochron. There is no common isotope on the ratio denominator. Rather, this plot shows two different isotope systems each with their own decay chain (&lt;Sup&gt;238&lt;/sup&gt;U-&gt;&lt;sup&gt;206&lt;/sup&gt;Pb and &lt;sup&gt;235&lt;/sup&gt;U-&gt;&lt;Sup&gt;207&lt;/sup&gt;Pb), these two Uranium decay chains have different half lives. The curved line is the &quot;concordia&quot; curve, which is the expected result if the sample exhibits closed-system behaviour (IE Pb has not diffused out of the crystal). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In this case a mineral (probably a zircon) was formed at 2.6 Ga and had open system behaviour at around 0.4 Ga. (IE the radiometric clock was partially reset). The straight line is called a &quot;discordia line&quot; and is a mixing line between the two time points on the concordia curve.&lt;/p&gt;&#xA;" OwnerUserId="4783" LastEditorUserId="2470" LastEditDate="2020-04-22T08:37:01.600" LastActivityDate="2020-04-22T08:37:01.600" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19630" PostTypeId="1" CreationDate="2020-04-23T09:31:21.783" Score="5" ViewCount="75" Body="&lt;p&gt;The lockdown imposed in China and other countries in response to the COVID 19 pandemic has resulted in a dramatic change in air quality. Factories and transport systems have shut or continue at greatly reduced capacity, so that emissions of many atmospheric pollutants are greatly reduced. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Studies of climate change have shown that atmospheric pollutants emitted by human activities contribute to anomalous cloud conditions which result in a net negative radiative forcing. Results from &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_SPM_FINAL.pdf&quot; rel=&quot;noreferrer&quot; title=&quot;WG1 Summary for Policy Makers&quot;&gt;IPCC 2013&lt;/a&gt; (see also &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiative_forcing&quot; rel=&quot;noreferrer&quot;&gt;the wikipedia page&lt;/a&gt; for the key IPCC results) gives an estimate of -0.82 W m-2, which offsets the positive contributions estimated at 3.18 W m-2, leading to a net forcing (in 2011) of 2.29 W m-2 (with substantial uncertainty on all terms). Removing the negative effects of the short-lived atmospheric pollutants would, based on these 2011 results, give a 39% increase in radiative forcing (as a best estimate -- with large uncertainties).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The questions: (1) have we, in the last few months, seen an increase in net anthropogenic radiative forcing of close to 40%? and (2) what are or could be the consequences of such a change both in the short term? &lt;/p&gt;&#xA;" OwnerUserId="17518" LastActivityDate="2020-04-23T09:31:21.783" Title="What is the radiative forcing change associated with the Chinese 2020 COVID lockdown, and how does this affect the circulation?" Tags="|atmosphere|climate-change|radiation-balance|aerosol|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19631" PostTypeId="1" AcceptedAnswerId="19971" CreationDate="2020-04-23T10:44:05.973" Score="2" ViewCount="59" Body="&lt;p&gt;I want to use an rainfall-runoff model for pluvial flash floods and need to choose for my synthetic rain event the appropriate duration. In the literature it often says that the chosen duration should be as long or twice as long as the runoff time from the beginning of the runoff until out of the catchment. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How do I estimate the runoff time? Perhaps somehow by considering the catchment area or the topography?&lt;/p&gt;&#xA;" OwnerUserId="18169" LastEditorUserId="2470" LastEditDate="2020-04-23T19:04:16.487" LastActivityDate="2020-07-24T19:31:37.777" Title="How to estimate the runoff time for my area?" Tags="|hydrology|models|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19633" PostTypeId="1" CreationDate="2020-04-26T09:15:19.000" Score="1" ViewCount="70" Body="&lt;p&gt;Currently there is a pond in one acre of land which is of 4 feet depth. If the pond is filled with water it is expected that some percent of the water will be absorbed by the ground under the pond. To what depth will the water will be absorbed by the ground? The type of soil is clay type.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The reason for asking the question is, there is a shrimp pond which is infected with a virus and it has been observed that in next few days the adjacent pond is infected with the virus and like that whole area is infected which is causing huge loss for the farmers. We are looking for the option to restrict the transmit of water from the adjacent ponds by placing a plastic/HDPE boundary kind of the thing for x feet depth so that our pond water doesn't get make contact with adjacent pond's water.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am interested to know the depth water can sink to the ground, to ask my query in a different way.. take a 4 ft dry pond and let's assume water is fully filled and the pond is kept ideal for a week. After a week how much depth the water would have sinked, can it be 20 ft or 30 ft or 40 ft or..?&lt;/p&gt;&#xA;" OwnerUserId="20344" LastEditorUserId="20344" LastEditDate="2020-04-27T05:26:50.147" LastActivityDate="2020-04-27T05:26:50.147" Title="What will be the depth that water can sink to the ground?" Tags="|soil-science|" AnswerCount="1" CommentCount="5" ClosedDate="2020-04-29T15:02:57.117" ContentLicense="CC BY-SA 4.0" />
  <row Id="19634" PostTypeId="1" CreationDate="2020-04-26T15:43:14.043" Score="1" ViewCount="314" Body="&lt;p&gt;I'm trying to understand the Richards equation that can be used to compute the flow of water in soil. In a textbook I found the following:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sQ7UF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sQ7UF.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Unfortunately, the textbook doesn't really explain what the pressure gradient actually is. Is it the matrix potential? Are the soil pores actually pulling water from the surface into the soil? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Or is it maybe the groundwater? The large the difference between surface and groundwatertable the higher the &quot;pressure gradient&quot;?&lt;/p&gt;&#xA;" OwnerUserId="18169" LastActivityDate="2020-04-26T20:52:22.173" Title="What is the &quot;pressure gradient&quot; within the richards equation" Tags="|hydrology|soil-science|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19635" PostTypeId="2" ParentId="19634" CreationDate="2020-04-26T20:52:22.173" Score="1" Body="&lt;p&gt;The pressure as measured at a point z+dz (dz infinitesimally small) and z.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the surface, pressure is the atmospheric pressure. Just below the surface, let's say at 1 cm depth, pressure is atmospheric pressure + whatever weight of the water column (taking into account saturation and so on).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the pressure gradient is in equilibrium with the gravity, you will have no flow (water in a glass do not mix, although at the top of the glass the pressure is lower than at the bottom, the water at the bottom feels a little push upwards equal and contrary to the push downward it receives from the weight of the water just above)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Think about this: you are at the bottom of a water reservoir (bottom not sealed). Pressure is the atmospheric pressure + depth of the reservoir. This is enough to induce a flow of water outwards from the reservoir, seeping below/through the dam.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/cBUp3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cBUp3.jpg&quot; alt=&quot;Nice figure from Olsen and Stephens (2016) https://www.researchgate.net/publication/319206472_RELEARNING_HOW_TO_LOOK_AT_PIEZOMETRIC_DATA_FOR_SEEPAGE_EVALUATION &quot;&gt;&lt;/a&gt;&#xA;Figure is not my own work, it is from a publication of Olsen and Stephens (2016) that can be found at this URL &lt;a href=&quot;https://www.researchgate.net/publication/319206472_RELEARNING_HOW_TO_LOOK_AT_PIEZOMETRIC_DATA_FOR_SEEPAGE_EVALUATION&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/publication/319206472_RELEARNING_HOW_TO_LOOK_AT_PIEZOMETRIC_DATA_FOR_SEEPAGE_EVALUATION&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2020-04-26T20:52:22.173" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19636" PostTypeId="2" ParentId="19633" CreationDate="2020-04-26T21:03:13.507" Score="0" Body="&lt;p&gt;One quick and dirty solution may be to lower the virus-pond level and raise the new-pond level ... so the flow should be from the new-pond to the virus-pond.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Soil being clay may mean the flow is happening below the soil ... if the virus-pond is in contact with the unit below the clay you may already have widespread contamination.&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2020-04-26T21:03:13.507" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19637" PostTypeId="2" ParentId="19610" CreationDate="2020-04-26T21:11:26.050" Score="2" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;There are fewer cars. Are they only a small part of Paris' air&#xA;  pollution?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Recent evolution of European standard on emissions for private vehicle means that the average car is polluting orders of magnitude less than the average gasoline-burning heater. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Even for a city plagued by the widespread use of huge, inefficent cars (New York), the heating systems (heat and hot water) may account for &gt;40% of the emissions &lt;a href=&quot;https://blogs.ei.columbia.edu/2019/01/15/heat-pumps-home-heating/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://blogs.ei.columbia.edu/2019/01/15/heat-pumps-home-heating/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A couple of emissions pie-charts for PM10 and PM2.5 for Paris in 2012 (from the report Inventaire régional des émissions en Ile-de-France Année de référence 2012 - éléments synthétiques Edition mai 2016 )&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vIsGn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vIsGn.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;and&#xA;&lt;a href=&quot;https://i.stack.imgur.com/dFoas.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dFoas.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5887" LastEditorUserId="5887" LastEditDate="2020-04-26T21:42:54.337" LastActivityDate="2020-04-26T21:42:54.337" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="19639" PostTypeId="2" ParentId="15423" CreationDate="2020-04-27T05:10:58.003" Score="1" Body="&lt;p&gt;Tipping point events have occurred throughout earth's history and parts of the earth system are currently being monitored for signs of abrupt change. Past earth system tipping points include &lt;em&gt;The Great Oxygenation&lt;/em&gt; which brought molecular oxygen (O&lt;sub&gt;2&lt;/sub&gt;) into the atmosphere and &lt;em&gt;Snowball Earth&lt;/em&gt; events where the earth's surface became ice-covered. Tipping points can occur on a planetary scale, as in the previous examples. These events can also occur on a regional  scale. For example, the West Antarctic Ice Sheet is a regional feature that is currently being monitored for signs of collapse.&lt;/p&gt;&#xA;" OwnerUserId="20365" LastActivityDate="2020-04-27T05:10:58.003" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19640" PostTypeId="1" CreationDate="2020-04-27T10:31:17.390" Score="3" ViewCount="98" Body="&lt;p&gt;I am trying to find out what forests were the largest in Western and Central Europe, around 600 BC. I understand that accounts dating that far back may be difficult to find, but I hope other sciences can tell us the extent of Classical forests in Europe.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I hope asking for two forests is not too much. If it is, I will change the question to the largest forest in modern-day France or Germany.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My best guess and research would lead me to believe the Black Forest was the largest in the period, and after that I'm not sure what the second largest would be. Today, the Landes Forest is the largest in France, but as far as I know that forest was planted in the 19th century.&lt;/p&gt;&#xA;" OwnerUserId="20379" LastActivityDate="2020-04-27T10:31:17.390" Title="What were the Two Largest Forests of Western and Central Europe (circa 600 BC)" Tags="|geography|earth-history|forest|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="19644" PostTypeId="1" CreationDate="2020-04-27T21:36:00.740" Score="2" ViewCount="103" Body="&lt;p&gt;Southern California is currently in the midst of a heat wave, which is an unwelcome stress for stay-at-home laws during the Covid-19 pandemic. Indeed, the California coast sees its warmest temperatures in well into the fall, peaking in September-November, often with a secondary peak through April-May. This is also the peak of the wildfire season. Go north about 300-600 miles to Washington or Oregon (and southwestern BC) and the warmest times of the year (plus the peak of the wildfire season) are smack dab in the middle of early July through to mid-August, like in most of the CONUS excluding the Desert Southwest. NOAA's map of when the average &quot;warmest day of the year&quot; is in the CONUS shows this difference quite clearly. Why the difference? I know that the California coast is Csa/Csb while Washington and Oregon and BC are Cfb, but I don't think that explains everything.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/t8A0C.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/t8A0C.jpg&quot; alt=&quot;NOAA warmest day of the year in CONUS&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2020-04-28T13:09:26.607" Title="Why do some parts of the West Coast of North America get hot later in the year than others?" Tags="|climate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19645" PostTypeId="2" ParentId="19644" CreationDate="2020-04-28T13:09:26.607" Score="1" Body="&lt;p&gt;I am not an expert, but ...&lt;/p&gt;&#xA;&#xA;&lt;p&gt;the pacific ocean has seasonal patterns:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0LGYM.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0LGYM.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;You can think of the water coming from the North being colder, the one from the South warmer.&#xA;On top of that, then you have associated rainfall etc. that will affect the climate (it can work both ways, warmer water may mean more rain, then more cloud coverage so less solar radiation so slightly colder days).&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2020-04-28T13:09:26.607" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19646" PostTypeId="1" CreationDate="2020-04-28T21:11:07.710" Score="4" ViewCount="714" Body="&lt;p&gt;I understand that trees capture CO&lt;sub&gt;2&lt;/sub&gt; from the air and use that carbon to grow. As trees reach mature height, do they begin to capture less CO2 as they would only need carbon for &quot;maintenance&quot; as opposed to &quot;growing taller&quot;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am trying to understand how to model expected CO&lt;sub&gt;2&lt;/sub&gt; capture for a given tree (my background is in math, not biology). I'm pretty sure my logic is flawed but not sure where...&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Trees capture CO&lt;sub&gt;2&lt;/sub&gt; primarily to get carbon for growth and maintenance.&lt;/li&gt;&#xA;&lt;li&gt;Therefore, trees need less carbon once mature.&lt;/li&gt;&#xA;&lt;li&gt;Therefore, mature trees capture less CO&lt;sub&gt;2&lt;/sub&gt; from the atmosphere.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="20387" LastEditorUserId="725" LastEditDate="2020-04-29T05:21:36.897" LastActivityDate="2020-04-29T19:30:06.250" Title="Do trees capture more CO2 during a fast growth stage?" Tags="|models|co2|forest|biogeochemistry|biomass|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19649" PostTypeId="2" ParentId="19646" CreationDate="2020-04-29T08:15:48.047" Score="5" Body="&lt;p&gt;Right, there are a lot of misconceptions about this. They are mostly to do with the difference between the magnitude of carbon &lt;em&gt;storage&lt;/em&gt; and the &lt;em&gt;rate&lt;/em&gt; of carbon uptake, and also the difference between whole site carbon storage and above ground biomass carbon storage. There is also ongoing research taking place which (as you might imagine) takes a &lt;em&gt;very&lt;/em&gt; long time because of the life expectancy of most tree species.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The standard forester's response is: a hectare of new forest will tend to grow on a Sigmoid / logistic curve (well described by &lt;a href=&quot;https://besjournals.onlinelibrary.wiley.com/doi/full/10.1111/j.2041-210X.2011.00155.x&quot; rel=&quot;noreferrer&quot;&gt;Paine et al. 2011&lt;/a&gt;) which looks like this:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yXEQe.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yXEQe.png&quot; alt=&quot;A Sigmoid growth curve for Sitka Spruce in the UK&quot;&gt;&lt;/a&gt;&#xA;This is based on an even aged stand (so, multiple trees, planted at the same time).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Interpreting this, we can see that the greatest &lt;em&gt;rate&lt;/em&gt; of carbon uptake is between years 25 and 75 (for this site, species, etc.) but the greatest level of carbon &lt;em&gt;storage&lt;/em&gt; is not really achieved until year 150+. You can read more about this in the infamous &lt;a href=&quot;https://www.forestresearch.gov.uk/research/forest-mensuration-a-handbook-for-practitioners/&quot; rel=&quot;noreferrer&quot;&gt;&quot;Blue Book&quot; by  Forest Research&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Based on this alone, we would assume that mature forests do not sequester much more additional carbon per ha per year, &lt;em&gt;but&lt;/em&gt; they do store a lot more than if we simply felled the forest to maximise carbon uptake. However... &lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Below ground carbon (soil carbon, roots, stumps etc.) doesn't follow the same rules. Carbon can remain sequestered in soils (particularly peat) for very long periods and can continue to be laid down (depending on site conditions) more or less indefinitely. When soils are disturbed (for example by felling operations or drainage) they release carbon. So any forest disturbance will tend to release soil carbon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) It doesn't scale well to individual trees as pointed out in in &lt;a href=&quot;https://www.nature.com/articles/nature12914&quot; rel=&quot;noreferrer&quot;&gt;Stephenson et al. (2014)&lt;/a&gt;. This is because the total tree population per ha is of a variable size (tree mortality and thinning means that there are fewer trees per ha over time). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This means we end up with a trade off between storing the carbon we have already sequestered and drawing down new carbon into the system. The degree to which the carbon sequestration rate decreases over time depends a lot on the forest soil, climate, species, and other local conditions. There is an academic discussion taking place over the difference between a simple measurement of above ground woody biomass (as shown above) and a whole-site carbon balance.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It can get quite complicated, and how you look at it can result in different results. Do you definitely want to model individual trees? Or are you thinking about forests in general?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hope this helps.&lt;/p&gt;&#xA;" OwnerUserId="18621" LastEditorUserId="18621" LastEditDate="2020-04-29T09:08:58.357" LastActivityDate="2020-04-29T09:08:58.357" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19650" PostTypeId="2" ParentId="19622" CreationDate="2020-04-29T13:08:54.293" Score="5" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Last month, the lower tropospheric temperature dropped 0.28°C from February to March, which seems like a huge drop even if it's due to seasonal reasons.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;That is not what the linked article says. It instead says that the monthly lower tropospheric temperature UAH anomaly dropped by 0.28°C from February to March. The monthly temperature anomaly is the difference between the worldwide average temperature for that month in some year and the worldwide average temperature for that month over a baseline set of years, 1981 to 2010 in the case of the UAH temperature anomaly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seasonal temperature variations tend to be much stronger over land than over ocean. The other is that the Northern Hemisphere contains significantly more land than does the Southern Hemisphere. The combination of these two effects make worldwide temperatures exhibit a seasonal variation that reflects seasons in the Northern Hemisphere. February to March marks the transition from meteorological winter to meteorological spring (which starts on March 1 rather than March 22). One would expect March to be warmer than February, worldwide.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is exactly what the GISTEMP records show:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KT85Z.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KT85Z.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;source: &lt;a href=&quot;https://data.giss.nasa.gov/gistemp/graphs_v4&quot; rel=&quot;noreferrer&quot;&gt;https://data.giss.nasa.gov/gistemp/graphs_v4&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Two key things can be extracted from the above graph: (1) There has been a general trend of warming since 1880, and (2) March 2020 was warmer than February 2020. What about monthly temperature anomalies, which is one of the topics in the question? The graph below portrays monthly GISTEMP temperature anomalies for recent years:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rzZR5.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rzZR5.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;source: Same as above&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The key relevant features from the above graphs is that while the monthly GISTEMP temperature for March 2020 was 0.62°C higher than that for February 2020, the monthly GISTEMP temperature anomaly for March 2020 was 0.06°C lower than that for February 2020.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thus GISTEMP, which is based on temperature measurements near the surface, may have seen a muted version of the effect observed in the UAH data, which are based on satellite observations. I used &quot;may have&quot; because the 0.06°C drop seen by the GISTEMP model is barely above the 0.05°C uncertainty claimed for that model. The UAH model claims the same uncertainty (0.05°C), so their reported 0.28°C drop was apparently real.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;My question is, is lower tropospheric temperature relevant to measuring global warming?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The graph below compares surface-based measures (MET office, NASA, and NOAA) with satellite-based estimates (RSS and UAH). The MET office data starts in 1850 while the satellite data (UAH and RSS) don't start until 1981.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/m161S.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/m161S.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;br&gt;&#xA;&lt;sup&gt;source: &lt;a href=&quot;https://www.carbonbrief.org/explainer-how-surface-and-satellite-temperature-records-compare&quot; rel=&quot;noreferrer&quot;&gt;https://www.carbonbrief.org/explainer-how-surface-and-satellite-temperature-records-compare&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All five datasets see the same general picture, which is temperatures generally rising, but with noisy peaks and troughs. Sometimes the satellite-based observations show variations that are not seen in the surface-based measurements, and other times it's the other way around. But in general, both see warming.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The satellites do not carry tethered thermometers that measure temperature at various heights in the atmosphere. They instead measure the intensities of electromagnetic radiation at various frequencies. The frequencies of interest for the UAH and RSS models are those at which the atmosphere is opaque.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are issues with this approach. Excessive cloudiness (or the lack of clouds) can confuse the algorithms used to translate observations to temperatures. The instruments that measure the data degrade, and degrade unequally. To counteract this latter effect, radiosondes that do measure temperature are regularly launched to coincide with satellite passes so that the satellite instruments and algorithms can be recalibrated. Finally, while the satellite data do show a recent sharp climb (recent meaning the last six years or so), it's not nearly as steep as the increase observed near the surface by weather stations that actually do use thermometers.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2020-04-29T13:16:12.887" LastActivityDate="2020-04-29T13:16:12.887" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19651" PostTypeId="2" ParentId="19471" CreationDate="2020-04-29T16:23:43.197" Score="4" Body="&lt;p&gt;My answer will only relate to the question in the title: Why is pressure on the poles higher in summer and lower in winter?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Due to the axis tilt of the earth the winter hemisphere gets less heated by solar radiation. This leads to a high temperature gradient from equator to the winter hemisphere pole (strong baroclinicity). In contrast we have a low temperature gradient from equator to the summer hemisphere pole. &#xA;The missing solar heating in the winter hemisphere additionally leads to descending air at the pole leading to &lt;strong&gt;low&lt;/strong&gt; pressure at jet stream level (around 300 hPa). On a non rotating planet the air would of course directly flow from the high pressure (equator) to the low pressure (pole) to remove the pressure gradient. As warm air would flow to the cold pole air, this would also weaken the temperature gradient. But due to the rotation of the earth, air flows around the area of low pressure. This flow gets increasingly stronger as the meridional temperature gradient strengthens. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;This maybe seen from thermal wind balance, which tells us that the geostrophic wind &lt;span class=&quot;math-container&quot;&gt;$V_g$&lt;/span&gt; is related to the temperature gradient &lt;span class=&quot;math-container&quot;&gt;$\nabla T$&lt;/span&gt; by&#xA;&lt;span class=&quot;math-container&quot;&gt;$\frac{\partial V_g}{\partial \ln p} = -\frac{R}{f}k \times \nabla T$&lt;/span&gt;.&#xA;Here &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; is pressure, &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; is the gas constant for dry air, &lt;span class=&quot;math-container&quot;&gt;$f$&lt;/span&gt; is the Coriolis parameter and &lt;span class=&quot;math-container&quot;&gt;$k$&lt;/span&gt; is vertical unit vector. Assuming there is no zonal temperature gradient, we can conclude that a strong meridional temperature gradient leads to an increasing change of &lt;span class=&quot;math-container&quot;&gt;$V_g$&lt;/span&gt; with height. We can observe this strong wind as the strong/weak jet stream in the winter/summer hemisphere. What does all of this have to with the pressure?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The jet stream acts as a barrier, dividing the warm and cold air masses. The Temperature will keep getting lower which will also increase the pressure and temperature gradient. In return the barrier (jet stream) gets stronger. This positive feedback mechanism remains until after winter solstice. Then the radiation reaching the pole will increase again, warming the air masses. Which will then lead to a weakening of the gradients.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So summarizing the above one could say, the missing radiation cools the air leading to a low pressure system at jet stream level. The jet stream itself gets stronger as the temperature gradient increases and acts as a barrier for warm and cold air masses and therefore maintains the pressure difference. &lt;/p&gt;&#xA;" OwnerUserId="18833" LastActivityDate="2020-04-29T16:23:43.197" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="19652" PostTypeId="1" CreationDate="2020-04-29T16:29:49.520" Score="1" ViewCount="49" Body="&lt;p&gt;Are the c.1500 year cyclical climate cycles called bond cycles or Dansgaard-Oeschger event(s)? I thought the Dansgaard-Oeschger event(s)? occur on much longer timescales. If so, why are they also called bond cycles? What is the correct terminology? Thank you.&lt;/p&gt;&#xA;" OwnerUserId="20391" LastActivityDate="2020-04-29T16:29:49.520" Title="Are Bond cycles Dansgaard-Oeschger event(s)?" Tags="|climate|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19653" PostTypeId="2" ParentId="18607" CreationDate="2020-04-29T19:06:12.070" Score="3" Body="&lt;p&gt;The species is &lt;a href=&quot;https://cloudatlas.wmo.int/en/varieties-stratocumulus-undulatus-sc-un.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stratocumuls undulatus&lt;/a&gt; Sc un.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They can form for example when cold, dry air moves over a warmer ground layer. A sharp wind shear at the boundary layer blows these waves. (&lt;a href=&quot;https://en.wikipedia.org/wiki/Stratocumulus_cloud&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia on Sc&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They are not to be confused with &lt;a href=&quot;http://Stratocumulus%20radiatus&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sc radiatus&lt;/a&gt; or yet another form, the so-called &quot;cloud streets&quot;, which form along the wind direction.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-04-29T19:49:39.120" LastActivityDate="2020-04-29T19:49:39.120" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19654" PostTypeId="2" ParentId="12149" CreationDate="2020-04-30T08:41:05.433" Score="1" Body="&lt;p&gt;This is a partial answer because I'm not an expert and because I don't know what the dynamic range of 137 dB means. Hopefully you can add a little more information.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;tl;dr:&lt;/strong&gt; if 137 dB is the dynamic range in power, then it's 68.5 dB in voltage and velocity which sounds more plausible, and makes the velocity sensitivity well below 1 micron per second. However we don't yet know what the noise and bandwidth of your signal are yet so we can't evaluate that.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;I have a few specs from the datasheet...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;The more information you share from the data sheet the better&lt;/em&gt; although I've now just noticed that the question is about three years old.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Also, there may be some helpful insight at &lt;a href=&quot;https://earthscience.stackexchange.com/q/16178/6031&quot;&gt;How sensitive are typical seismometers?&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;137 dB is a factor of &lt;span class=&quot;math-container&quot;&gt;$10^{-137/10} = 10^{-13.7} =$&lt;/span&gt; 2E-14.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Let's assume&lt;/strong&gt; &lt;strong&gt;&lt;em&gt;just for a moment&lt;/em&gt;&lt;/strong&gt; that the dynamic range applies to voltage and velocity, rather than power.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the full scale is 20 Volts then the minimum resolution (ignoring noise) is 4E-13 Volts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the sensitivity is 2400 V per m/s then it's &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{4 \times 10^{-13} \text{ V}}{2400 \text{V per m/s}} \approx 1.7 \times 10^{-16} \text{m/s} $$&lt;/span&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;which is &lt;span class=&quot;math-container&quot;&gt;$1 \times 10^{-10}$&lt;/span&gt; microns per second, and absurdly low number.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;On the other hand if the 137 dB is power&lt;/strong&gt; then we multiply the 20 V by &lt;span class=&quot;math-container&quot;&gt;$10^{-137/\mathbf{20}} = 10^{-6.85} =$&lt;/span&gt; 1.4E-7 to get a minimum resolution (again ignoring noise) is 2.8E-6 Volts, and&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{2.8 \times 10^{-6} \text{ V}}{2400 \text{V per m/s}} \approx 1.2 \times 10^{-9} \text{m/s} $$&lt;/span&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;which is &lt;span class=&quot;math-container&quot;&gt;$1.2 \times 10^{-3}$&lt;/span&gt; microns per second or about 1 nanometer per second, which is indeed a realistic number for some &lt;a href=&quot;https://en.wikipedia.org/wiki/Capacitive_displacement_sensor#Precision_positioning&quot; rel=&quot;nofollow noreferrer&quot;&gt;capacitive&lt;/a&gt; and &lt;a href=&quot;https://electronics.stackexchange.com/a/460877/102305&quot;&gt;optical&lt;/a&gt; displacement sensors. It sounds &lt;em&gt;plausible&lt;/em&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2020-04-30T08:47:43.673" LastActivityDate="2020-04-30T08:47:43.673" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19655" PostTypeId="1" CreationDate="2020-04-30T12:43:30.100" Score="5" ViewCount="1568" Body="&lt;p&gt;This seems like a really simple question, but I have been struggling for a couple of days to find an answer online or in the ERA documentation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I am using ERA5 and ERA Interim reanalyses to get atmospheric profiles for a model I am running.&#xA;However, the model requires values to be given at fixed values of altitude (above sea level) (it is a rectangular grid 60x60x60 km).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data I get from ERA (downloaded using the python script API they suggest) gives me data on either pressure level or model level. I can get geopotential as a variable, but there is no option for 'real-world' height.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So my question is how do I calculate the 'real' altitude of each level?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I initially tried dividing geopotential by 9.81, but I'm not sure that's quite right, as geopotential is an integral of g.&#xA;Alternatively should I be using the values in the tables &lt;a href=&quot;https://www.ecmwf.int/en/forecasts/documentation-and-support/60-model-levels&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;, and if so why are they not provided as an option of a variable or coordinate when downloading the data?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Apologies in advance if this is a silly question with a simple answer and thanks for your help.&lt;/p&gt;&#xA;" OwnerUserId="20395" LastActivityDate="2020-10-12T15:51:31.980" Title="How to calculate 'real-world' geometric height from ERA reanalysis data" Tags="|reanalysis|era|coordinate-system|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19656" PostTypeId="2" ParentId="18758" CreationDate="2020-05-01T17:27:53.187" Score="2" Body="&lt;p&gt;Actually, you probably shouldn't install it. If you're comfortable using Linux, then you would be better advised to use the docker container instead, with it already installed. That way your system stays clean and you can have someone else maintain it for you.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Check docker hub for different versions and find the one you like (&lt;a href=&quot;https://hub.docker.com/search?q=esmf&amp;amp;type=image&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Install docker using: &lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;curl -LSs get.docker.com | sh&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&#xA;&lt;p&gt;There are plenty of simple docker tutorials that will help you work out how to use it.&lt;/p&gt;&#xA;" OwnerUserId="18362" LastActivityDate="2020-05-01T17:27:53.187" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19657" PostTypeId="1" CreationDate="2020-05-01T18:06:42.200" Score="1" ViewCount="37" Body="&lt;p&gt;I'm trying to understand at a high level the relationship of aerosols to the global temperature and I'm new to these concepts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have Stratoshperic mean global AOD data from:&lt;br/&gt;&#xA;&lt;a href=&quot;https://data.giss.nasa.gov/modelforce/strataer/tau.line_2012.12.txt&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://data.giss.nasa.gov/modelforce/strataer/tau.line_2012.12.txt&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Global temperature anomaly from here:&lt;br/&gt;&#xA;&lt;a href=&quot;https://data.giss.nasa.gov/gistemp/graphs/graph_data/Global_Mean_Estimates_based_on_Land_and_Ocean_Data/graph.txt&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://data.giss.nasa.gov/gistemp/graphs/graph_data/Global_Mean_Estimates_based_on_Land_and_Ocean_Data/graph.txt&lt;/a&gt;&#xA;&lt;br/&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the scatterplot for the non-smoothed global mean temperature anomaly and AOD:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OfmJ7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OfmJ7.png&quot; alt=&quot;Annual Mean Temperature&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/GGF0R.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GGF0R.png&quot; alt=&quot;Global AOD&quot;&gt;&lt;/a&gt;&#xA;&lt;br&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My understanding is that the Aerosols decreases the temperature and it has short term effects. So the negative sign seems ok to me but is the magnitude here makes sense? i.e. the Aerosol has a weak relationship with the global temperature?&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;      Temp       aod&#xA;Temp  1.0       -0.113206&#xA;aod  -0.113206   1.000000&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="20396" LastEditorUserId="20396" LastEditDate="2020-05-02T14:23:41.733" LastActivityDate="2020-05-02T14:23:41.733" Title="Correlation of Global Stratospheric AOD with Global Mean Temperature Anomaly" Tags="|climate-change|climate|aerosol|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19658" PostTypeId="2" ParentId="19610" CreationDate="2020-05-01T19:59:27.513" Score="1" Body="&lt;h2&gt;1&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Your linked report contradicts this &lt;a href=&quot;https://phys.org/news/2020-03-virus-lockdown-big-dent-paris.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;one reported on phys.org&lt;/a&gt; that suggests a huge increase in air-quality in Paris. This matches &lt;a href=&quot;https://phys.org/news/2020-04-air-quality-cities-action-covid-.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;similar reports&lt;/a&gt; from the rest of the world that lockdown has improved air-quality. That I can easily find studies that contradict your reference makes me doubt the veracity of the information it is presenting (and the evidence in the articles I have referenced).&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;2&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Measuring air-quality is a relatively new discipline that is still rapidly developing (&lt;a href=&quot;https://phys.org/news/2020-03-first-time-proof-chemical-reactions-particulates.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;, &lt;a href=&quot;https://phys.org/news/2020-03-ammonia-portraying-air-pollution-impacts.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;, &lt;a href=&quot;https://phys.org/news/2020-04-air-quality-busy-australian-roads.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;), and many more). It is not likely that any individual measurement is actually accurate. In science, it is usually the case that consensus must be built over time, statistically, before anything is accepted as actually true. This suggests that before we believe a result we should confirm it. The lack of maturity in this field makes me doubt the veracity of the claims in your link, and the claims in my link too. In fact, our default position should be to doubt everything until there is a sufficient weight of evidence that gives us enough confidence to believe it.&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;3&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Logically, if you reduce a major pollutant for a significant period of time it seems very likely that pollution will fall. If you observer something different from that you must be suspicious of your results and attempt to verify them through a different set of observations performed using different techniques. This argument also makes me doubt the veracity of the claims in your link (and again, in mine).&lt;/p&gt;&#xA;&#xA;&lt;h2&gt;4&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Ultimately, there is little strong evidence from these testing organisations to come to a conclusion on whether air quality has improved or not. There is the logical argument however that suggests that it should have improved, so we should weigh our opinions with that. Given this, it seems more likely that air-quality has improved, and given a lack of scientific consensus we should lean towards a belief that it has improved, rather than stayed the same.&lt;/p&gt;&#xA;" OwnerUserId="18362" LastEditorUserId="18362" LastEditDate="2020-05-01T20:05:02.323" LastActivityDate="2020-05-01T20:05:02.323" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19659" PostTypeId="1" AcceptedAnswerId="19661" CreationDate="2020-05-02T10:30:38.110" Score="7" ViewCount="116" Body="&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/2883/20404&quot;&gt;Weather balloons&lt;/a&gt;, as well as &lt;a href=&quot;https://en.wikipedia.org/wiki/Weather_reconnaissance#Aircraft&quot; rel=&quot;noreferrer&quot;&gt;specially prepared aircrafts&lt;/a&gt;, are used to retrieve several atmosphere parameters at different altitudes that are latter used to feed &lt;a href=&quot;https://earthscience.stackexchange.com/q/19/20404&quot;&gt;mathematical models&lt;/a&gt; for weather prediction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Nowadays airliners are already fitted with multiples sensors (static pressure, temperature, weather radar,..). Those airliners are flying almost all over the world continuously, and are thus able to provide tons of weather data. In many regions (inside &lt;a href=&quot;https://en.wikipedia.org/wiki/Terminal_control_area&quot; rel=&quot;noreferrer&quot;&gt;TMA&lt;/a&gt; and above) data can be retrieve from ground level to 12000m above mean sea level. Those data won't be as complete as data collected by weather balloons, but can be considered as additional data.&#xA;Yet, airliners are operated by private company and exchanging such data can be subjected to commercial contracts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are airliners, whose primary mission is not to collect weather data but to transport cargo or passengers, used to retrieve additional data to feed mathematical weather prediction models on a daily basis?&lt;/p&gt;&#xA;" OwnerUserId="20404" LastActivityDate="2020-05-02T22:27:10.007" Title="Are airliners sensors used to feed weather prediction models?" Tags="|weather-forecasting|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19660" PostTypeId="2" ParentId="19659" CreationDate="2020-05-02T20:40:31.210" Score="6" Body="&lt;p&gt;Besides other data like satellites, radar, radiosondes, etc. data from commercial airliners are collected and included in the assembly as well. As an example, here's the description of the &lt;a href=&quot;https://www.dwd.de/EN/research/weatherforecasting/num_modelling/01_num_weather_prediction_modells/icon_description.html&quot; rel=&quot;noreferrer&quot;&gt;ICON&lt;/a&gt; model from the DWD (German met office).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the chapter &quot;&lt;a href=&quot;https://www.dwd.de/EN/research/weatherforecasting/num_modelling/02_data_assimilation/data_assimilation.html;jsessionid=05F978C9141E9FC00B600E796595BA14.live11041?nn=484268&quot; rel=&quot;noreferrer&quot;&gt;Data Assimilation&lt;/a&gt;&quot; they write:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Direct measurements of classical atmospheric variables are also carried out by commercial airplanes. Thus, we obtain a high quantity of measurements in a whole atmospheric column from the ground to about 12km height close to airports, as well as regular measurements along typical flight routes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I would assume that other national or international services use the same datasets for their models.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastActivityDate="2020-05-02T20:40:31.210" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19661" PostTypeId="2" ParentId="19659" CreationDate="2020-05-02T22:27:10.007" Score="10" Body="&lt;p&gt;Indeed, airlines are equipped to measure atmospheric data and then put into weather models. The WorldMeteorological Organization's program is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Aircraft_Meteorological_Data_Relay&quot; rel=&quot;noreferrer&quot;&gt;AMDAR&lt;/a&gt;. Several articles highlight the impact that the lack of flights have had on the initialization of weather models.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.npr.org/sections/coronavirus-live-updates/2020/04/03/826848818/one-more-coronavirus-problem-accurate-weather-forecasts&quot; rel=&quot;noreferrer&quot;&gt;https://www.npr.org/sections/coronavirus-live-updates/2020/04/03/826848818/one-more-coronavirus-problem-accurate-weather-forecasts&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.boston25news.com/news/local/covid-19-forecast-how-grounded-flights-are-impacting-weather-forecasting-data/RB7HY6G5ONGE3EHROUKSKT4SB4/&quot; rel=&quot;noreferrer&quot;&gt;https://www.boston25news.com/news/local/covid-19-forecast-how-grounded-flights-are-impacting-weather-forecasting-data/RB7HY6G5ONGE3EHROUKSKT4SB4/&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are a few papers that explore the impact that aircraft data has on initialization:&#xA;&lt;a href=&quot;https://journals.ametsoc.org/doi/full/10.1175/MWR-D-17-0380.1&quot; rel=&quot;noreferrer&quot;&gt;https://journals.ametsoc.org/doi/full/10.1175/MWR-D-17-0380.1&lt;/a&gt;&#xA;&lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-14-00055.1&quot; rel=&quot;noreferrer&quot;&gt;https://journals.ametsoc.org/doi/pdf/10.1175/BAMS-D-14-00055.1&lt;/a&gt;&#xA;&lt;a href=&quot;https://journals.ametsoc.org/doi/pdf/10.1175/2009WAF2222321.1&quot; rel=&quot;noreferrer&quot;&gt;https://journals.ametsoc.org/doi/pdf/10.1175/2009WAF2222321.1&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-05-02T22:27:10.007" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19662" PostTypeId="1" CreationDate="2020-05-03T04:52:18.857" Score="5" ViewCount="81" Body="&lt;p&gt;I am trying to filter my Bouguer anomaly data to remove the short wavelength features. I have created a lowpass filter to achieve this, but I am wondering how I can more objectively choose my cutoff wavelength(s).  This filtering is done in the Fourier domain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The filtering technique is similar to what is described in this &lt;a href=&quot;https://www.researchgate.net/publication/266079150_A_Methodology_for_Filtering_and_Inversion_of_Gravity_Data_An_Example_of_Application_to_the_Determination_of_the_Moho_Undulation_in_Morocco&quot; rel=&quot;noreferrer&quot;&gt;paper&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Currently, I am just very loosely basing the wavelengths off of my elastic plate thickness, and comparing (via observation and RMSE) the resulting Bouguer anomaly to my predicted model.&lt;/p&gt;&#xA;" OwnerUserId="20377" LastActivityDate="2020-05-03T04:52:18.857" Title="How do you choose appropriate parameters for a lowpass filter when filtering a Bouguer anomaly?" Tags="|geology|geophysics|models|gravity|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19664" PostTypeId="1" CreationDate="2020-05-04T10:38:47.940" Score="4" ViewCount="974" Body="&lt;p&gt;I know that the best possible approximation of the shape of earth is an oblate sphere. But people also call it as geo-spherical shape of the Earth. What is the meaning of geospherical shape? Does this mean that the shape of Earth itself is unique and hence a word geospherical is used to define that shape but for mathematical calculations we use oblate as the closest approximation.&lt;/p&gt;&#xA;" OwnerUserId="20412" LastEditorUserId="6016" LastEditDate="2020-05-05T11:33:21.757" LastActivityDate="2022-01-09T16:01:40.163" Title="Geo-Spherical shape of Earth" Tags="|geology|geophysics|earth-history|planetary-science|planets|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19665" PostTypeId="1" AcceptedAnswerId="19681" CreationDate="2020-05-04T17:03:06.450" Score="1" ViewCount="84" Body="&lt;p&gt;I am just wondering what is the real impact of Precision agriculture. I came across Airbus Intelligence and their Earth Observation services (Agriculture, forestry, environment) - It seems nice and attractive - however What is the real impact of using it? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;PS: You can link me even French articles or topics (I am curious about French agriculture)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thanks!   &lt;/p&gt;&#xA;" OwnerUserId="18631" LastEditorUserId="18631" LastEditDate="2020-05-05T15:15:44.757" LastActivityDate="2020-05-06T19:51:13.287" Title="What is real impact of Precision Agriculture?" Tags="|agriculture|satellites|weather-satellites|" AnswerCount="1" CommentCount="10" ClosedDate="2020-05-06T04:26:52.733" ContentLicense="CC BY-SA 4.0" />
  <row Id="19666" PostTypeId="1" CreationDate="2020-05-04T20:38:28.860" Score="3" ViewCount="274" Body="&lt;p&gt;Due to thermohaline circulation, the Pacific water is more 'aged' so there is a higher amount of total dissolved inorganic carbon (e.g. CO&lt;sub&gt;2&lt;/sub&gt;) in the deep Pacific when compared to the Atlantic. However, I don't know how this affects the relative &lt;sup&gt;13&lt;/sup&gt;C/&lt;sup&gt;12&lt;/sup&gt;C enrichment of the Pacific.&#xA;Factors I've thought about:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Oxic respiration of buried organic matter is the source of CO&lt;sub&gt;2&lt;/sub&gt; in the deep ocean.&lt;/li&gt;&#xA;&lt;li&gt;Deep Pacific water has accumulated more respired CO&lt;sub&gt;2&lt;/sub&gt; since the Pacific is at the end of the deep circulation.&lt;/li&gt;&#xA;&lt;li&gt;Algae and microbes fractionate against &lt;sup&gt;13&lt;/sup&gt;C in favour of &lt;sup&gt;12&lt;/sup&gt;C.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="20414" LastEditorUserId="2470" LastEditDate="2020-05-05T04:14:11.810" LastActivityDate="2020-05-06T09:23:03.260" Title="Is CO2 in the Pacific Ocean depleted or enriched in Carbon-13 compared to the Atlantic, and why?" Tags="|geochemistry|co2|carbon-cycle|thermohaline-circulation|pacific|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19667" PostTypeId="1" CreationDate="2020-05-04T20:57:38.447" Score="4" ViewCount="502" Body="&lt;p&gt;My understanding is that the Hawaiian islands were produced as the Pacific plate moved over a stationary hot spot, which sent magma burning up through the plate as it passed over, forming a trail of volcanic islands on top.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But why dots instead of a line? In other words, why did that process produce islands instead of a continuous piece of land? Does the rising magma start and stop periodically?&lt;/p&gt;&#xA;" OwnerUserId="18728" LastActivityDate="2022-03-16T04:55:36.163" Title="Why aren't the Hawaiian islands a continuous strip of land?" Tags="|plate-tectonics|hotspot|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19668" PostTypeId="1" CreationDate="2020-05-05T03:07:14.993" Score="1" ViewCount="27" Body="&lt;p&gt;Was dinosaur blood really red? Was the vegitation really green?Can that filter be used today?&lt;/p&gt;&#xA;" OwnerUserId="20416" LastActivityDate="2020-05-05T04:03:45.867" Title="Filtered pressured oxygen 80 miilion years ago" Tags="|human-influence|oxygen|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19669" PostTypeId="2" ParentId="2415" CreationDate="2020-05-05T04:00:24.880" Score="2" Body="&lt;p&gt;If I look at Google Earth imagery, it is not just the Hawaii Emperor Seamount Chain, but also those of Louisville Hotspot Chain and Society or Pitcairn Hotspot Chains show a slight bend , the Louisville Chain shows a more 'graceful' bend like a gradual 30° bend and Society or Pitcairn somewhere like 40° bend and the Hawaii emperor seamount chain shows a more abrupt bend - like almost 60°. This I suspect could be due to relative changes in the expansion rate of  the southernmost (Pact plate+ Antarctic Plate) and eastern sections (Pac Plate+Nazca) of the East Pacific rise after disappearance of the former Phoenix plate (underneath East Antarctica) , as well as a failure of the Indo Australian ridge spreading at 90 East ridge somewhere 45 to 43 Mya, after which Australia started moving northward instead of Eastward so the vector product of the 2 plate motions now has a different direction which has direct bearing on the hotspot track vector.&lt;/p&gt;&#xA;&lt;p&gt;The northern segment of Farallon Plate has subducted under North America , and the oldest remnants of Emperor Hotspot track are undergoing flat slab subduction at the cusp of Aleutian and Kuril Kamchatka trenches in the vicinity of Kommandor and Attu Island - this accounts for the cessation or relative 'inactivity' of volcanism in this segment of the otherwise volatile Pacific ring of fire as less seepage of ocean water into trench and formation of accretionary prism from the volcanic rocks on track guyots.&lt;/p&gt;&#xA;&lt;p&gt;Consider that in the absence of West to East stresses from the breakup of Indo-Australian plate over the East west spreading 90 East ridge , the Galapagos rise E-W spreading center in the Pacific is able to make its impact felt on the E-W spreading direction and the resultant vector product of pacific plate movement is now oriented in a east-north easterly direction instead of being north by north east directed and no longer driven exclusively from the pacific antarctic ridge  . The impact of this is attenuated the further south you get so Louisville hotspot chain is less impacted , but nevertheless shows a bend .&lt;/p&gt;&#xA;&lt;p&gt;Contrary to the mainstream thought, subduction does not drive plate tectonics, rather its seafloor spreading or rifting that does. Subduction is just a terminal effect of forces acting from the spreading centre. Mantle Current intensity at spreading ridges drives subduction at distal ends .  Another thing I strongly suspect is that modern East And West Antarctica were different continental cratons that fused after a small ocean that separated them closed and this suture is now marked by the Mid Antarctic mountain system. In fact a total ice melt of Antarctica may still reveal a tiny oceanic waterway remnant. So it is highly likely the seafloor spread rate between Pacific and Nazca plates increased substantially after 45 - 40 Mya.&lt;/p&gt;&#xA;&lt;p&gt;Primary Ref :&#xA;&lt;a href=&quot;https://www.nature.com/articles/ncomms15660&quot; rel=&quot;nofollow noreferrer&quot;&gt;Torsvik, T., Doubrovine, P., Steinberger, B. et al. Pacific plate motion change caused the Hawaiian-Emperor Bend. Nat Commun 8, 15660 (2017).&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.com/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=&amp;amp;ved=2ahUKEwi1gOiblvvvAhXSGs0KHRtzA34QFjACegQIBBAD&amp;amp;url=http%3A%2F%2Fwww.earthdynamics.org%2Fsteinberger%2Fpapers%2Fi0091-7613-35-5-407.pdf&amp;amp;usg=AOvVaw3xndyiSein-bxcRHKJqhL6&quot; rel=&quot;nofollow noreferrer&quot;&gt;Plate-tectonic reconstructions predict part of the Hawaiian hotspot&#xA;track to be preserved in the Bering Sea&#xA;Bernhard Steinberger; Carmen Gaina :&#xA;Center for Geodynamics, Geological Survey of Norway, Leiv Eirikssons vei 39,N-7491 Trondheim, Norway &lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;And more useful background info here on Panthalassa.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/ngeo1401&quot; rel=&quot;nofollow noreferrer&quot;&gt;Intra-Panthalassa Ocean subduction zones revealed by fossil arcs and mantle structure&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://arstechnica.com/science/2012/03/before-the-pacific-putting-ancient-islands-back-on-the-map/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Before the Pacific: finding the lost islands of a Pangea-era ocean&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Ninety_East_Ridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ninety East ridge-Wiki&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://drs.nio.org/drs/bitstream/handle/2264/3723/Geophys_Res_Lett_37_L17304a.pdf;jsessionid=461CB977F758BA6481C26138CB4EA5FD?sequence=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sager, W. W.; Paul, C.F.; Krishna, K.S.; Pringle, M.S.; Eisin, A.E.; Frey, F.A.; Rao, D.G.; Levchenko, O.V. (September 2010). &amp;quot;Large fault fabric of the Ninetyeast Ridge implies near-spreading ridge formation&amp;quot; (PDF).&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20417" LastEditorUserId="20417" LastEditDate="2021-04-13T12:09:34.903" LastActivityDate="2021-04-13T12:09:34.903" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19670" PostTypeId="2" ParentId="19668" CreationDate="2020-05-05T04:03:45.867" Score="1" Body="&lt;p&gt;What filter?  Modern vertebrate blood is always red (with just one exception AFAIK: &lt;a href=&quot;https://en.wikipedia.org/wiki/Channichthyidae&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Channichthyidae&lt;/a&gt; ) because it is based on hemoglobin.  Given that birds, which descend from one branch of the dinosaurs, have red blood, it's likely that the dinosaurs did as well.  Likewise plants are mostly green due to the chlorophyll used for photosynthesis, another thing that would be strongly conserved by evolution.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2020-05-05T04:03:45.867" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19671" PostTypeId="2" ParentId="19667" CreationDate="2020-05-05T09:36:15.507" Score="6" Body="&lt;p&gt;Don't be mislead by the subaerial part, it is actually &lt;a href=&quot;https://pubs.usgs.gov/gip/dynamic/Hawaiian.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;a ridge&lt;/a&gt; on a large scale but neither the lava &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2003JB002559&quot; rel=&quot;nofollow noreferrer&quot;&gt;production rate&lt;/a&gt; nor erosion rates are constants. That leaves the ridge with higher and lower parts, as well as gaps. Furthermore reef building biocenoses change shape and appearance of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Evolution_of_Hawaiian_volcanoes&quot; rel=&quot;nofollow noreferrer&quot;&gt;eroding volcanic edifices&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Hawaiian (and other like for instance the Canarian) volcanoes go through &lt;a href=&quot;http://volcano.oregonstate.edu/book/export/html/113&quot; rel=&quot;nofollow noreferrer&quot;&gt;stages&lt;/a&gt; during their lifetime with different production rates and magma composition. Connections to the &lt;a href=&quot;https://hilo.hawaii.edu/~kenhon/GEOL205/Ascent/default.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;magma chamber(s)&lt;/a&gt; may remain in place for some time while the volcanic edifice moves relative to the magma source(*), until it has moved so far away that rising magma seeks new ascent channels to rise and deformation forms new dykes and cracks and so it may erupt from different vents, and that from a possible complex and subdivided magma chamber(s) fed by the plume underneath.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;That process may leave an appearance of single detached volcanoes like e.g. M. Loa and M. Kea, but they are just similar things at different stages. Many volcanoes never reach a subaerial state and remain submerged, contributing to the appearance of detached islands.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(*) i would say, whether it is the plate that moves or the plume or the connections between plume and magma chambers is mostly irrelevant. Base argument is that the rate is not constant and eruptions may seek different paths during time. As to the exact why and how, that's ongoing discussion.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-05-13T09:05:32.373" LastActivityDate="2020-05-13T09:05:32.373" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19672" PostTypeId="5" CreationDate="2020-05-05T13:07:13.863" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2020-05-05T13:07:13.863" LastActivityDate="2020-05-05T13:07:13.863" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19673" PostTypeId="4" CreationDate="2020-05-05T13:07:13.863" Score="0" Body="The flow of air with respect to the ground. On the surface of the Earth, wind consists of the bulk movement of air." OwnerUserId="6016" LastEditorUserId="6016" LastEditDate="2020-05-05T20:20:41.537" LastActivityDate="2020-05-05T20:20:41.537" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19674" PostTypeId="5" CreationDate="2020-05-05T13:09:36.753" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2020-05-05T13:09:36.753" LastActivityDate="2020-05-05T13:09:36.753" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19675" PostTypeId="4" CreationDate="2020-05-05T13:09:36.753" Score="0" Body="For questions relating to the liquid phase of water (H₂O), specifically its structure, properties, and uses in meteorology and Earth Science." OwnerUserId="6016" LastEditorUserId="81" LastEditDate="2020-05-06T17:59:15.407" LastActivityDate="2020-05-06T17:59:15.407" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19676" PostTypeId="5" CreationDate="2020-05-05T13:14:17.507" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2020-05-05T13:14:17.507" LastActivityDate="2020-05-05T13:14:17.507" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19677" PostTypeId="4" CreationDate="2020-05-05T13:14:17.507" Score="0" Body="For questions about the outermost layer of the surface of the Earth. The soil is saturated with organic remains and rock particles." OwnerUserId="6016" LastEditorUserId="6016" LastEditDate="2020-05-05T20:20:22.073" LastActivityDate="2020-05-05T20:20:22.073" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19678" PostTypeId="1" CreationDate="2020-05-05T15:42:05.463" Score="1" ViewCount="50" Body="&lt;p&gt;Cross-posted in &lt;a href=&quot;https://worldbuilding.stackexchange.com/q/175614/75041&quot;&gt;Worldbuilding&lt;/a&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Curious what the affects on daily temperatures and climate would be if the Earth had a slower rotation, say 84 hours of light and 84 hours of darkness. How extreme would the daily highs/lows be? Would there be a significant increase in storms? When would they occur (dawn/dusk)?&lt;/p&gt;&#xA;" OwnerUserId="20420" LastActivityDate="2020-05-05T15:42:05.463" Title="Effect on climate of the Earth’s rotation was a week instead of 24 hours" Tags="|meteorology|climate|temperature|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19680" PostTypeId="2" ParentId="18718" CreationDate="2020-05-05T23:49:28.983" Score="0" Body="&lt;p&gt;You are likely to reference Statistical Methods in the Atmospheric Sciences, by Wilks in your thesis.&#xA;Also this &lt;a href=&quot;https://www.cawcr.gov.au/projects/verification/&quot; rel=&quot;nofollow noreferrer&quot;&gt;webpage&lt;/a&gt; concerning different aspects of many metrics used in verifying forecasts.&lt;/p&gt;&#xA;" OwnerUserId="20423" LastActivityDate="2020-05-05T23:49:28.983" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19681" PostTypeId="2" ParentId="19665" CreationDate="2020-05-05T23:54:12.017" Score="1" Body="&lt;p&gt;This is a placeholder answer in anticipation of (1) the question being closed before I can write a valid answer, and (2) I will replace this placeholder with a valid answer.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have now partially filled in the placeholder, but what I wrote obviously still needs references.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;The hope is that precision agriculture will be the basis for the next Green Revolution. The first Green Revolution started in the late 1950s and picked up steam during the 1960s. These techniques, now 50 to 60 years old, drastically changed farming in many developing countries, and even turned some of those countries from net food importers to net food exporters. The gains from those now dated techniques have plateaued in many places as of late; in some places productivity has even begun declining.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The goals of precision agriculture are to integrate many aspects of the earth and agricultural sciences with late 20th / early 21st century technology (modern direct sensing, remote sensing, internet of things, big data, ...)  so as to identify on a very precise scale exactly which land areas are in need of enhanced irrigation, fertilization, insecticides, herbicides, etc., -- and which areas are just fine as-is. The hopes are that this will reduce the overall need for irrigation, etc., thereby reducing stress on the land, and that this will be largely automated, thereby reducing the workload on farm workers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These are the aims and hopes. The concepts do appear to be working in highly developed areas. But whether they can work well in the developing world is a bit suspect, let alone whether they can work at all in undeveloped areas of the world.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The bigger problem is that many estimates indicate the Earth's human population will increase by almost thirty per cent in just thirty years (from a bit over 7.5 billion to almost 10 billion) -- and that increase will be happening while the first Green Revolution is plateauing / declining. Something has to be done lest many parts of the world fall into famine. Precision agriculture might be one way address this bigger problem. Or it might not.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2020-05-06T19:51:13.287" LastActivityDate="2020-05-06T19:51:13.287" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19682" PostTypeId="1" AcceptedAnswerId="19712" CreationDate="2020-05-06T09:17:23.497" Score="4" ViewCount="871" Body="&lt;p&gt;Intuitively if the Earth were to rotate fast enough from west to east, the average sea level would be noticeably higher on the west edge of the oceans. Does Earth's rotation cause this effect in reality?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I ask as in Bill Bryson's book 'A Short History of Nearly Everything' on p.334 ch.18, he says&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The Pacific is about a foot and a half [~46cm] higher along its western edge - a consequence of the centrifugal force created by the Earth's spin.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;No source is mentioned in the notes section and I found no exact source with a Google search. The closest I found was&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://oceanservice.noaa.gov/facts/globalsl.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Is sea level the same all across the ocean? - National Ocean Service&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is the &lt;em&gt;change&lt;/em&gt; in sea level from 1993 to I assume 2019 (when the article was last updated). The data shows an &lt;em&gt;increase&lt;/em&gt; in sea level on the Pacific's west side (and not the east side) but of course this is not exactly what Bryson stated in his book. Maybe there has been a mix up?&lt;/p&gt;&#xA;" OwnerDisplayName="user20424" LastActivityDate="2020-05-08T06:37:27.277" Title="Does Earth's rotation cause sea levels to increase from east to west?" Tags="|oceanography|sea-level|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="19683" PostTypeId="2" ParentId="19666" CreationDate="2020-05-06T09:23:03.260" Score="1" Body="&lt;p&gt;&quot;The decrease in &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C as water flows from the Atlantic to the North Pacific is due mainly to the addition of organically produced material and its subsequent oxidation as it falls through the water column. Marine organic carbon has a &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C of near -25&lt;sup&gt;0&lt;/sup&gt;/&lt;sub&gt;00&lt;/sub&gt;, hence the addition of this material decreases the &amp;delta;&lt;sup&gt;13&lt;/sup&gt;C of the &amp;Sigma;CO&lt;sub&gt;2&lt;/sub&gt;.&quot; (from conclusion)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;P. M. Kroopnick, &lt;em&gt;Deep-Sea Research Part a-Oceanographic Research Papers&lt;/em&gt;, 1985, &lt;strong&gt;32&lt;/strong&gt;, 57-84.&#xA;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/0198014985900172&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/0198014985900172&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20415" LastActivityDate="2020-05-06T09:23:03.260" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19684" PostTypeId="5" CreationDate="2020-05-06T10:48:09.940" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2020-05-06T10:48:09.940" LastActivityDate="2020-05-06T10:48:09.940" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19685" PostTypeId="4" CreationDate="2020-05-06T10:48:09.940" Score="0" Body="The center of our solar system. Questions in regards to sunlight or solar related questions. " OwnerUserId="6016" LastEditorUserId="6016" LastEditDate="2020-05-06T17:57:10.893" LastActivityDate="2020-05-06T17:57:10.893" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19686" PostTypeId="5" CreationDate="2020-05-06T10:50:01.847" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2020-05-06T10:50:01.847" LastActivityDate="2020-05-06T10:50:01.847" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19687" PostTypeId="4" CreationDate="2020-05-06T10:50:01.847" Score="0" Body="Questions related to the solid phase of water." OwnerUserId="6016" LastEditorUserId="81" LastEditDate="2020-05-06T17:58:27.083" LastActivityDate="2020-05-06T17:58:27.083" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19688" PostTypeId="5" CreationDate="2020-05-06T10:55:05.217" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2020-05-06T10:55:05.217" LastActivityDate="2020-05-06T10:55:05.217" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19689" PostTypeId="4" CreationDate="2020-05-06T10:55:05.217" Score="0" Body="Questions about the processes, theories and evidence for the formation of planetary bodies, mostly the Earth. " OwnerUserId="6016" LastEditorUserId="6016" LastEditDate="2020-05-06T17:57:06.053" LastActivityDate="2020-05-06T17:57:06.053" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19690" PostTypeId="1" CreationDate="2020-05-06T17:20:43.147" Score="3" ViewCount="78" Body="&lt;p&gt;I recall that after 9/11, when all US flights were canceled, there was a statistically detectable bump in average temperature. Something about jet contrails disappearing for 4 days. Has anything like that happened during the recent COVID-19 drop in US air traffic? Sorry I don't have the reference to the 9/11 data/story.&lt;/p&gt;&#xA;" OwnerUserId="20427" LastActivityDate="2021-03-26T02:24:56.620" Title="Has recent drop in airline flights over the US had a measurable warming effect as was found after 9/11?" Tags="|climate-change|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19691" PostTypeId="1" CreationDate="2020-05-06T17:49:28.317" Score="1" ViewCount="292" Body="&lt;p&gt;I have a doubt regarding a step in the derivation of the momentum equation in spherical coordinates. I am referring to the textbook &quot;Fundamentals of Atmospheric Modeling&quot; by Mark Jacobson, 2nd Edition, Chapter 4, Page 86. The change in unit vector in the x direction, delta i, is described using geometry. The text describes the angle between delta i and Re (The radius of Earth) as phi, the latitude. I do not understand how this can be so. Only after understanding this can I proceed to the expression for delta i in vector form. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can anyone help please?&lt;a href=&quot;https://i.stack.imgur.com/1cqQ9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1cqQ9.png&quot; alt=&quot;The coordinates&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6QMfn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6QMfn.png&quot; alt=&quot;The geometrical description&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KsQne.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KsQne.png&quot; alt=&quot;The equations, the one labelled 4.7 is what I do not understand&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20428" LastActivityDate="2020-05-06T17:49:28.317" Title="Derivative of the Unit Vector in Spherical Coordinate system" Tags="|atmosphere-modelling|coordinate-system|" AnswerCount="0" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19692" PostTypeId="5" CreationDate="2020-05-06T18:00:06.343" Score="0" Body="" OwnerUserId="81" LastEditorUserId="81" LastEditDate="2020-05-06T18:00:06.343" LastActivityDate="2020-05-06T18:00:06.343" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19693" PostTypeId="4" CreationDate="2020-05-06T18:00:06.343" Score="0" Body="Questions concerning the gaseous phase of water" OwnerUserId="81" LastEditorUserId="81" LastEditDate="2020-05-06T18:00:06.343" LastActivityDate="2020-05-06T18:00:06.343" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19694" PostTypeId="2" ParentId="19690" CreationDate="2020-05-06T20:53:06.120" Score="0" Body="&lt;p&gt;I had to look at Mauna Loa data myself for the heck of it. No change to the roughly 2 ppm increase each year, presently at 416.6 ppm. I am somewhat surprised , not because of the reduced air traffic, but the reduced auto traffic which is the significantly greater amount of CO 2 . &lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2020-05-06T20:53:06.120" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19695" PostTypeId="2" ParentId="19690" CreationDate="2020-05-06T22:46:45.593" Score="2" Body="&lt;p&gt;It's not clear yet; this is an area of active research which it itself hampered by COVID-19 social distancing requirements, according to this report on &lt;a href=&quot;https://www.climatechangenews.com/2020/04/09/coronavirus-plane-free-skies-spur-research-warming-impact-aviation/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate Change News&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Scientists with Nasa and European research groups hope to use clear&#xA;  skies to narrow down massive uncertainties about the warming effect of&#xA;  condensation trails – the wispy white lines that criss-cross the skies&#xA;  in the wake of jets engines.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;“The air traffic system has not been diminished to the current levels&#xA;  since the days following 9/11,” said Patrick Minnis of Nasa Langley&#xA;  Research Center, who is joining a research effort to study&#xA;  high-altitude clouds.&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;“Flight groundings at the scales initiated in response to the&#xA;  coronavirus pandemic are a significant opportunity to better quantify&#xA;  the impact of air traffic on cloud cover via contrail formation.”&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;As to the post-9/11 effect:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;The new research builds on studies after the 9/11 suicide hijackings&#xA;  in the US grounded flights for a few days. One study, for instance,&#xA;  found that the plane-free skies had an impact on temperature&#xA;  variations in the United States, but some researchers say the findings&#xA;  might have been caused by natural variations.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2020-05-06T22:46:45.593" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19696" PostTypeId="1" CreationDate="2020-05-07T02:58:55.437" Score="3" ViewCount="216" Body="&lt;p&gt;IFL Science's &lt;a href=&quot;https://www.iflscience.com/environment/earths-north-magnetic-pole-is-heading-towards-siberia-and-scientists-now-know-why/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth's North Magnetic Pole Is Heading Towards Siberia – And Scientists Now Know Why&lt;/a&gt; explains that the motion of Earth's north magnetic pole can be understood as follows:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;A new study, published this week in the journal &lt;a href=&quot;https://www.nature.com/articles/s41561-020-0570-9&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nature Geoscience&lt;/a&gt;, argues the changes could be explained by the to-ing and fro-ing between two magnetic &quot;blobs&quot; of molten material in the planet's interior, causing a titanic shift of its magnetic field.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;See also The BBC's &lt;a href=&quot;https://www.bbc.com/news/science-environment-52550973&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scientists explain magnetic pole's wanderings&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are these blobs sufficiently distinct to describe their locations somehow, perhaps with spherical coordinates like latitude, longitude and distance from the center from the Earth, or some cartesian scheme?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;em&gt;Where are they?&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6258" LastEditDate="2020-05-25T05:10:27.953" LastActivityDate="2020-05-28T12:39:18.013" Title="What &quot;blobs&quot; of molten material in Earth's interior are responsible for the rapidly moving north pole? Where are these blobs exactly?" Tags="|geomagnetism|convection|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="19697" PostTypeId="2" ParentId="19262" CreationDate="2020-05-07T03:02:46.397" Score="0" Body="&lt;p&gt;&quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth%27s_atmosphere#Current_concentration&quot; rel=&quot;nofollow noreferrer&quot;&gt;Each part per million by volume of &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; in the atmosphere represents approximately 2.13 gigatonnes of carbon&lt;/a&gt;&quot;. Per a_donda's comment,&quot;During the carboniferous, atmospheric &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; sank from ~1500 to ~250ppm&quot;, so, about 2.7 trillion tonnes. &quot;&lt;a href=&quot;https://www.worldcoal.org/coal/where-coal-found&quot; rel=&quot;nofollow noreferrer&quot;&gt;There are an estimated 1.1 trillion tonnes of proven coal reserves worldwide.&lt;/a&gt;&quot; The latter number does not include coal already burnt, so the quantities are comparable.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, there are other contributions:&lt;br&gt;&#xA;1) Dissolved &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; would come out of the oceans.&lt;br&gt;&#xA;2) Volcanos emit &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; over millions of years.&lt;br&gt;&#xA;3) Coal &quot;reserves&quot; is defined as what can be mined. Unmineable quantities may be 20 times greater.&lt;br&gt;&#xA;...&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2020-05-07T03:02:46.397" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19698" PostTypeId="5" CreationDate="2020-05-07T09:52:33.800" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2020-05-07T09:52:33.800" LastActivityDate="2020-05-07T09:52:33.800" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19699" PostTypeId="4" CreationDate="2020-05-07T09:52:33.800" Score="0" Body="For questions related specifically to the Python dynamic programming language." OwnerUserId="6016" LastEditorUserId="6016" LastEditDate="2020-05-07T11:32:01.487" LastActivityDate="2020-05-07T11:32:01.487" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19700" PostTypeId="5" CreationDate="2020-05-07T09:54:45.323" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2020-05-07T09:54:45.323" LastActivityDate="2020-05-07T09:54:45.323" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19701" PostTypeId="4" CreationDate="2020-05-07T09:54:45.323" Score="0" Body="Questions related to an organized collection of a large amount of persistent data." OwnerUserId="6016" LastEditorUserId="6016" LastEditDate="2020-05-07T11:28:11.003" LastActivityDate="2020-05-07T11:28:11.003" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19702" PostTypeId="5" CreationDate="2020-05-07T09:57:13.187" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2020-05-07T09:57:13.187" LastActivityDate="2020-05-07T09:57:13.187" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19703" PostTypeId="4" CreationDate="2020-05-07T09:57:13.187" Score="0" Body="The theory of the electric and magnetic fields, both in the static and dynamic case, in relation of the Earth." OwnerUserId="6016" LastEditorUserId="6016" LastEditDate="2020-05-07T11:30:29.987" LastActivityDate="2020-05-07T11:30:29.987" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19704" PostTypeId="5" CreationDate="2020-05-07T09:59:14.700" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2020-05-07T09:59:14.700" LastActivityDate="2020-05-07T09:59:14.700" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19705" PostTypeId="4" CreationDate="2020-05-07T09:59:14.700" Score="0" Body="Questions regarding the 8th chemical element, a main component of the athmosphere and of the crust." OwnerUserId="6016" LastEditorUserId="6016" LastEditDate="2020-05-07T11:29:55.307" LastActivityDate="2020-05-07T11:29:55.307" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19706" PostTypeId="5" CreationDate="2020-05-07T10:02:24.750" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2020-05-07T10:02:24.750" LastActivityDate="2020-05-07T10:02:24.750" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19707" PostTypeId="4" CreationDate="2020-05-07T10:02:24.750" Score="0" Body="An allotrope of oxygen with the general formula $\rm{O_3}$. The ozone layer in the atmosphere plays an essential part to protect Earth from the ultraviolet radiation of the Sun." OwnerUserId="6016" LastEditorUserId="6016" LastEditDate="2020-05-07T11:30:45.680" LastActivityDate="2020-05-07T11:30:45.680" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19708" PostTypeId="2" ParentId="19682" CreationDate="2020-05-07T11:44:21.960" Score="0" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;I ask as in Bill Bryson's book 'A Short History of Nearly Everything' on p.334 ch.18, he says&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Pacific is about a foot and a half [~46cm] higher along its western edge - a consequence of the centrifugal force created by the Earth's spin.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Bryson is right in the sense that in places there is a difference in height between the eastern Pacific and western Atlantic, at least in some places. He is however wrong about the magnitude of that height difference and wrong about the cause. From the &lt;a href=&quot;https://www.psmsl.org/train_and_info/faqs/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Permanent Service for Mean Sea Level&lt;/a&gt;,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Sea level is about 20 cm higher on the Pacific side [of the Panama Canal] than the Atlantic due to the water being less dense on the Pacific side, on average, and due to the prevailing weather and ocean conditions. Such sea level differences are common across many short sections of land dividing ocean basins.&lt;/p&gt;&#xA;&lt;p&gt;The 20 cm difference is determined by geodetic levelling from one side to the other. This levelling follows a 'level' surface which will be parallel to the geoid (see FAQ #1). The 20 cm difference at Panama is not unique. There are similar 'jumps' elsewhere e.g. Skagerrak, Indonesian straits.&lt;/p&gt;&#xA;&lt;p&gt;If the canal was open sea and did not contain locks, i.e. if somehow a deep open cutting had been made rather than the canal system over the mountains, then there would be a current flowing from the Pacific to the Atlantic. An analogy, though imperfect because there are many other factors, is a comparison between Panama and the Drake Passage off the south tip of Chile, which has a west-east flow. (The flow in the Drake Passage is primarily wind-driven, but Pacific-Atlantic density must play some role.)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="239" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-05-07T11:44:21.960" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19709" PostTypeId="2" ParentId="16744" CreationDate="2020-05-07T12:13:31.730" Score="5" Body="&lt;p&gt;From the comments:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;And indeed, after browsing trough a few sections they seem to assume that &amp;quot;Liquid metal separates rapidly from liquid silicate&amp;quot;, like oil and water, and they don't mix later. Very interesting. I wonder what's @Gimelist opinion about this.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You are very correct.&lt;/p&gt;&#xA;&lt;p&gt;The answer is simple: the core and mantle are immiscible. The core doesn't dissolve into the mantle because it's not soluble in the mantle.&lt;/p&gt;&#xA;&lt;p&gt;This is precisely why we have the core and mantle to begin with.&lt;/p&gt;&#xA;&lt;p&gt;My answer here is very relevant: &lt;a href=&quot;https://worldbuilding.stackexchange.com/a/123951/39999&quot;&gt;https://worldbuilding.stackexchange.com/a/123951/39999&lt;/a&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Let's take a hypothetical very simple core and mantle composition:&lt;/p&gt;&#xA;&lt;p&gt;The core is made of pure iron (&lt;span class=&quot;math-container&quot;&gt;$\ce{Fe}$&lt;/span&gt;), and the mantle is fayalite (&lt;span class=&quot;math-container&quot;&gt;$\ce{Fe2SiO4}$&lt;/span&gt;).&lt;/p&gt;&#xA;&lt;p&gt;What happens when you chemically react the two by &lt;span class=&quot;math-container&quot;&gt;$\ce{Fe + Fe2SiO4}$&lt;/span&gt;? Absolutely nothing. There is no intermediate &lt;span class=&quot;math-container&quot;&gt;$\ce{Fe3SiO4}$&lt;/span&gt;. Does not exist. So they just stay as separate iron and fayalite. And because iron is much denser than fayalite, it stays down at the core, whereas the fayalite is the mantle above it.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Edit:&lt;/p&gt;&#xA;&lt;p&gt;Here's a recent paper describing the overall redox conditions of Earth compared to its neighbours:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1038/s41467-020-15757-0&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1038/s41467-020-15757-0&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;May be of relevance.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2020-06-23T11:40:16.900" LastActivityDate="2020-06-23T11:40:16.900" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19710" PostTypeId="5" CreationDate="2020-05-08T06:18:37.663" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2020-05-08T06:18:37.663" LastActivityDate="2020-05-08T06:18:37.663" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19711" PostTypeId="4" CreationDate="2020-05-08T06:18:37.663" Score="0" Body="Asphalt lakes are tar pits that form when a type of petroleum called bitumen is forced from underground up to the Earth's surface. Usually occurring along fault lines, the bitumen pools at the surface and the lighter elements vaporize, leaving a pool of natural asphalt." OwnerUserId="6129" LastEditorUserId="6129" LastEditDate="2020-05-08T08:30:58.450" LastActivityDate="2020-05-08T08:30:58.450" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19712" PostTypeId="2" ParentId="19682" CreationDate="2020-05-08T06:37:27.277" Score="0" Body="&lt;p&gt;The centrifugal effect of the Earth's rotation causes both sea-level and the &quot;solid&quot; Earth to bulge at the Equator, so that the radius at the Equator is about 22km greater than the radius at the pole &lt;a href=&quot;https://en.wikipedia.org/wiki/Equatorial_bulge?wprov=srpw1_0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia: Equatorial Bulge&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The direct dynamical effect of rotation does not cause any East-West variation in sea-level. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There are two more effects to take into account. The Earth is not a homogeneous sphere, but has significant density variations. Because of these density variations the shape of the geoid (&lt;a href=&quot;https://en.wikipedia.org/wiki/Geoid&quot; rel=&quot;nofollow noreferrer&quot;&gt;&quot;the shape that the ocean surface would take under the influence of the gravity and rotation of Earth alone&quot;&lt;/a&gt;). The structure of these density variations caused the Pacific to be &quot;higher&quot; (i.e. further from centre of the Earth) in the West (&lt;a href=&quot;https://www.esri.com/news/arcuser/0703/geoid1of3.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mean Sea Level, GPS, and the Geoid&lt;/a&gt;). This appears to the main cause of the difference that Bill Bryson refers to.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Discussion of the &quot;height&quot; of sea-level can be confusing, because scientists often talk about the height relative to the geoid. Winds and ocean currents affect level of the ocean so that it does not match the shape of the geoid exactly. In fact, the prevailing winds tend to create a positive height relative to the geoid on the Eastern edge of the Pacific (&lt;a href=&quot;https://manoa.hawaii.edu/exploringourfluidearth/physical/atmospheric-effects/effect-surface-currents&quot; rel=&quot;nofollow noreferrer&quot;&gt;Effect of Surface Currents&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="17518" LastActivityDate="2020-05-08T06:37:27.277" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19713" PostTypeId="2" ParentId="17707" CreationDate="2020-05-08T06:47:29.107" Score="1" Body="&lt;p&gt;Andesite can present very large vugs, unconnected massive pores, then it may explain a mass density &amp;lt; 2 kg/m&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt;.&#xA;Since the pores may not be connected, you may have porosity of 16%, while the pore space in reality is much bigger, up to 75%.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If it is basaltic andesite it may be very hard, with the the added Si content, if it &lt;em&gt;just&lt;/em&gt; andesite it is relatively hard to drill. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If drilling in such environment, the proper diamond drill bit is a must. I am not aware if you can have backhoe with diamond teeth.&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2020-05-08T06:47:29.107" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19716" PostTypeId="1" CreationDate="2020-05-08T20:38:22.427" Score="2" ViewCount="160" Body="&lt;p&gt;I believe, Earth could be approximated by a molten, metallic, non-magnetic sphere, with a molten stony sphere around it. However,&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;As far I know, the magnetic properties of the lava in the crust, in its temperature and pressure, is not very well known.&lt;/li&gt;&#xA;&lt;li&gt;The case is the same, for a greater extent, to the core. As far I know, the core is mostly a mix of different elements, with a large part of iron, so the amount and ratio of the non-ironic part might affect significantly the permeability.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;I believe, getting the answer to this question could be better answered experimentally. However, in its naive form (getting a current around the equator) it seems unfeasible.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Corresponding this, I found nothing by google. Maybe lesser direct measurements are possible (like the interaction of the Earth's magnetic field to some external one?)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it known? How was it calculated?&lt;/p&gt;&#xA;" OwnerUserId="6016" LastActivityDate="2020-05-08T20:38:22.427" Title="What is the relative (magnetic) permeability of the Earth? How could it be measured?" Tags="|geomagnetism|electromagnetism|paleomagnetism|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19717" PostTypeId="1" AcceptedAnswerId="19718" CreationDate="2020-05-09T09:24:02.780" Score="1" ViewCount="140" Body="&lt;p&gt;Providing there are low wind conditions and a clear sky, will the 1 km x 1 km black surface create an upward convention?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let’s say I were to do this at 60&lt;span class=&quot;math-container&quot;&gt;$^\circ$&lt;/span&gt; N longitude in march month, the elevation of the site to be at 2000 feet, by just building a surface of 1 km x 1 km and painted in black, how high would the convection go? What other side effects will it cause? My goes to have air going up to 7000 feet constantly.&lt;/p&gt;&#xA;" OwnerUserId="20435" LastEditorUserId="2470" LastEditDate="2020-05-09T12:50:05.427" LastActivityDate="2020-05-10T09:37:37.190" Title="If I build a concrete surface on a 1km x 1km area and painted it black, will I create convection (updraft from ground)?" Tags="|meteorology|atmosphere|atmospheric-radiation|convection|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19718" PostTypeId="2" ParentId="19717" CreationDate="2020-05-09T11:48:56.623" Score="2" Body="&lt;p&gt;In principle: yes. But i won't give exact numbers for a mere km², though i'd expect a skilled paraglider under optimal atmopsheric conditions to be able to make some use of it ;-)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Actually, gliders use industrialized areas exactly because of this, a &lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Albedo&quot; rel=&quot;nofollow noreferrer&quot;&gt;low albedo&lt;/a&gt;&lt;/em&gt; created by asphalt, concrete, dense construction/building.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How high and strong the resulting &lt;em&gt;thermal convection&lt;/em&gt; will be depends on the weather, atmospheric layering, solar irradiation, wind, cloud cover, temperature and moisture. The ability of the ground to store heat (e.g. street canyons, or heat strored in the air of a high grown cornfield) also influences the triggering of convection. In some cases a rising thermal is visualized by a &lt;em&gt;dust devil&lt;/em&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Thermal convection can be calculated/estimated and predicted from &lt;em&gt;atmospheric soundings&lt;/em&gt;, instrumented weather balloons to measure the state of the atmopshere from ground to tropopause. The results are visualized in &lt;a href=&quot;https://en.wikipedia.org/wiki/Skew-T_log-P_diagram&quot; rel=&quot;nofollow noreferrer&quot;&gt;Skew-T&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/St%C3%BCve_diagram&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stüve&lt;/a&gt; diagrams.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.csun.edu/~hmc60533/CSUN_103/weather_exercises/soundings/smog_and_inversions/Understanding%20Stuve_v3.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reading and interpreting&lt;/a&gt; them is an art. But they can tell when the &lt;em&gt;trigger temperature&lt;/em&gt; for thermals will be reached, how high they go, if there will be clouds and at which level their base is, etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Side effects of this are called &lt;a href=&quot;https://scied.ucar.edu/longcontent/urban-heat-islands&quot; rel=&quot;nofollow noreferrer&quot;&gt;urban heat islands&lt;/a&gt; or generally heat islands due to low albedo ground. They can cause local low pressure due to the rising air over the hotter ground, which can result in showers or even thunderstorms in the evening/afternoon.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Quite obviously, these effects can also be triggered by naturally occurring differences in ground albedo and plant cover. They are a driving force for local weather phenomena.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-05-10T09:37:37.190" LastActivityDate="2020-05-10T09:37:37.190" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19719" PostTypeId="2" ParentId="14558" CreationDate="2020-05-09T18:26:19.253" Score="-1" Body="&lt;p&gt;UVvertical Index = UVdirect Index + UVdiffuse&lt;/p&gt;&#xA;&#xA;&lt;p&gt;UVdirect Index (vertical) = cos(altitude angle)*(UVhorizontal Index)/(sin(altitude angle)+coefReflection)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;UVdiffuse (vertical) = (UVhorizontal Index)/(sin(altitude angle)+coefReflection)*coefReflection*0,55+0,437*cos(altitude angle)&lt;em&gt;cos(45)+0,313&lt;/em&gt;(cos(altitude angle)*cos(45))^2&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Reflection Coefficient varies during the year, its average value is 0.1.&lt;/p&gt;&#xA;" OwnerUserId="19165" LastActivityDate="2020-05-09T18:26:19.253" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19721" PostTypeId="2" ParentId="19717" CreationDate="2020-05-10T04:42:22.410" Score="2" Body="&lt;p&gt;Yes.  You don't even need concrete or black paint, just a plowed field will do, or grass vs forest, a south facing slope...  (Ask anyone who's done much sailplane flying.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How high the convection will reach depends on a lot of factors.  Hereabouts (east side of the Sierra Nevada) you can easily thermal to 14,000 ft (~4500 m) or more. (Going higher requires you to use supplemental oxygen.)  If there is the proper amount of moisture in the air, it will reach a height at which the moisture starts to condense and form clouds.  These can be simple cumulus clouds &lt;a href=&quot;https://en.wikipedia.org/wiki/Cumulus_cloud&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Cumulus_cloud&lt;/a&gt; or they can develop into cumulonimbus, which can reach heights of 69K ft/21K m) or more.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastActivityDate="2020-05-10T04:42:22.410" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19723" PostTypeId="2" ParentId="19579" CreationDate="2020-05-11T18:43:18.943" Score="3" Body="&lt;p&gt;If they propagate outward from thunderstorms, they are outflow boundaries. Cold air flows down from the thunderstorm with precipitation and spreads outward upon hitting the ground. This air moves ahead of the storm and forces warmer air upward, suspending clouds and other particles. That's what is visible on radar.&#xA;More: &lt;a href=&quot;https://en.wikipedia.org/wiki/Outflow_boundary&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Outflow_boundary&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18303" LastActivityDate="2020-05-11T18:43:18.943" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19724" PostTypeId="2" ParentId="13922" CreationDate="2020-05-11T18:59:12.100" Score="4" Body="&lt;p&gt;Neither hurricanes nor tornadoes burn out because they get &quot;too strong&quot;. Their strength is dependent on how supportive the atmospheric conditions are. If a hurricane stays in the same place for too long, moves over land, or moves over colder water, it will weaken. Likewise, a tornado will weaken if its parent storm moves into less favorable conditions and weakens.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;All storms operate at &quot;maximum strength&quot; - they always are using all the energy that is available to them.&lt;/p&gt;&#xA;" OwnerUserId="18303" LastActivityDate="2020-05-11T18:59:12.100" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19725" PostTypeId="2" ParentId="13052" CreationDate="2020-05-11T19:17:09.257" Score="1" Body="&lt;p&gt;When a parcel of dry air with a given initial temperature rises, it cools at a specific rate - the dry adiabatic lapse rate. If the surrounding environment cools at a slower rate with height than the parcel, the parcel will eventually be colder than the environment and sink. On the other hand, if the environment cools faster than the parcel does, the parcel remains warmer than the environment and rises freely.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So for a parcel of dry air to continue to rise, the environmental lapse rate needs to be greater than the dry adiabatic lapse rate. Surface heating does a really efficient job of increasing low-level environmental lapse rates, which is why dust devils are more common when there's more sun.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm not a scientist, so I can't tell you an exact number, but the dry adiabatic lapse rate is 9.8 degrees Celsius per kilometer, or 3.3 degrees Fahrenheit per 1,000 ft. So if the environment cools at over 1 degree C per 100 meters, it will likely be conducive to dust devils.&lt;/p&gt;&#xA;" OwnerUserId="18303" LastActivityDate="2020-05-11T19:17:09.257" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19726" PostTypeId="2" ParentId="2300" CreationDate="2020-05-12T06:04:09.600" Score="1" Body="&lt;p&gt;It is possible to change a storm a tiny bit by harvesting some of the wind energy atleast localy by using wind mills.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The energy of even the weakest storm is multiple gigawatts and in a strong storm the energy can reach into the range of terrawatts,unless we can harvest a significant part of this it will be impossible to change a storms force or direction in a significant way.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In a city large buildings will weaken the wind but only localy,the problem with cities is they are heat islands so the rising heat can start the wind blowing and in theory start the formation of a storm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Cloud seeding is only effective for limiting the wind in a small area,as far as i know cloud seeding have been tried on storms before with very limited effect on the windspeed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the answer to your question is no it is not possible to change the force or direction of a storm in a significant way.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastActivityDate="2020-05-12T06:04:09.600" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19727" PostTypeId="1" CreationDate="2020-05-12T15:22:52.490" Score="1" ViewCount="17" Body="&lt;p&gt;I'm trying to look into relationships between juvenile Hogfish which recruit in sea grass habitats to adult abundance data that move to deeper offshore reef and hard bottom habitat. I have data from both areas but on different scales. The juvenile data is local and regional, the adult data is the entire west Florida shelf. There are some scaling issues there and I was wondering if anyone knows of any studies that are similar to this, especially if they used trawl data? The data I'm looking at has about 87% zeros. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've found studies that  cover ZIP and staged analysis such as: &lt;code&gt;Yogita S. Wagh &amp;amp; Kirtee K. Kamalja (2018) Zero-inflated models and estimation in zero-inflated Poisson distribution, Communications in Statistics - Simulation and Computation, 47:8, 2248-2265, DOI: 10.1080/03610918.2017.1341526&lt;/code&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What I can't seem to find is anyone comparing juvenile abundance and year class data to adult abundance using similar but different size gears in different environments and/or at different scales. I've found something close here: &lt;code&gt;Ali Arab, Mark L. Wildhaber, Christopher K. Wikle &amp;amp; Casey N. Gentry (2008) Zero-Inflated Modeling of Fish Catch per Unit Area Resulting from Multiple Gears: Application to Channel Catfish and Shovelnose Sturgeon in the Missouri River, North American Journal of Fisheries Management, 28:4, 1044-1058, DOI: 10.1577/M06-250.1&lt;/code&gt;&lt;/p&gt;&#xA;" OwnerUserId="20444" LastActivityDate="2020-05-12T15:22:52.490" Title="Does anyone know of any studies comparing juvenile and adult abundance data for an ontogenetic reef fish?" Tags="|oceanography|models|literature-request|estuary|" AnswerCount="0" CommentCount="0" ClosedDate="2020-05-20T00:55:47.693" ContentLicense="CC BY-SA 4.0" />
  <row Id="19728" PostTypeId="2" ParentId="2300" CreationDate="2020-05-12T21:16:11.167" Score="-2" Body="&lt;p&gt;Clap your hands ... this is the human equivalent of a &lt;a href=&quot;https://en.wikipedia.org/wiki/Butterfly_effect&quot; rel=&quot;nofollow noreferrer&quot;&gt;butterfly effect&lt;/a&gt;. Storm systems are chaotic, so tiny perturbations to the atmosphere grow rapidly and, eventually, alter the trajectory of future systems. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The drawback of this approach is that it is impossible to predict the magnitude or direction of the influence you have on any given system. Clapping your hands will not affect the path of an approaching storm, but, according to Lorenz's theory of chaos, it will eventually affect the path of storms -- perhaps a few months later. Alter storm intensity or direction in a controlled way is much harder.&lt;/p&gt;&#xA;" OwnerUserId="17518" LastEditorUserId="17518" LastEditDate="2020-05-12T21:22:12.233" LastActivityDate="2020-05-12T21:22:12.233" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19729" PostTypeId="1" AcceptedAnswerId="19731" CreationDate="2020-05-12T21:42:27.850" Score="7" ViewCount="643" Body="&lt;p&gt;If we had access to a totally new kind of rock (maybe a new meteorite), is it possible to tell what the rock is composed of without touching it / drilling into it?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm thinking of something like firing sound waves or some kind of electromagnetic radiation at it and seeing what emerges from the other side.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Are there any techniques like this in geology? &lt;/p&gt;&#xA;" OwnerUserId="20446" LastEditorUserId="725" LastEditDate="2020-05-13T23:20:12.783" LastActivityDate="2020-05-13T23:20:12.783" Title="Non-invasive techniques to find rock composition" Tags="|geochemistry|rocks|economic-geology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19730" PostTypeId="2" ParentId="2300" CreationDate="2020-05-12T23:20:56.860" Score="3" Body="&lt;p&gt;There are numerous ways. Arguably, some we are already doing, but are not intended (such as urbanization and the emission of different pollutants). But I'll suppose you are wondering about intentional modifications. Moreover, this is perhaps too general of a question, as there are a variety of different types of storms, of varying sizes. I'll tackle what I can, in a reasonable fashion. And for the sake of argument, I'll just ignore the downsides.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Let me repeat that, I will ignore the downsides. This may yield a comedic effect.&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Extratropical cyclones.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Being that these take the energy from baroclinicity, a good way of disrupting the intensity of these storms is to warm the cold area and cool the warm area. You can do whatever you want to do to accomplish that, be it drop a couple megaton nuclear bombs in the cold region, etc. &lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;Tornadoes&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;One thing you need to know about tornadoes is that the storms that generate these rely on stability/buoyancy and shear. Leveling everything should reduce the shear. Covering the surface with ice should also promote a more stable atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;Hurricanes&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Hurricanes derive much of their energy from the temperature and entropy difference between the surface and the tropopause. Also, increasing the drag can reduce the wind speed. &lt;a href=&quot;https://www.aoml.noaa.gov/hrd/hrd_sub/modification.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Different ways to do these can be found in NOAA.&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Certainly these aren't all the ways that the weather can be modified. But these are just some. Of course, anything we do may backfire. Extratropical cyclones serve a purpose-transporting energy and momentum. Even hurricanes move water vapor towards the poles. And to that, I'll quote Jeff Goldblum:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...[Y]our scientists were so preoccupied with whether or not they could that they didn't stop to think if they should.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-05-12T23:20:56.860" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19731" PostTypeId="2" ParentId="19729" CreationDate="2020-05-12T23:41:48.303" Score="11" Body="&lt;p&gt;You are looking for a &lt;a href=&quot;https://duckduckgo.com/?q=portable%20xrf&amp;amp;iar=images&amp;amp;iax=images&amp;amp;ia=images&quot; rel=&quot;noreferrer&quot;&gt;portable XRF&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Ydpxi.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ydpxi.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It does (almost) exactly what you said. It sends electromagnetic radiation to the rock (X-rays), which excites electrons in the atoms and when they bounce back they return X-ray of different energies which are detected by the instrument. It looks like this, for example:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ftFx9.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ftFx9.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Using the different peaks you can figure out what the rock is made of.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is not as good as lab-based XRF, but it's so easy to use it's now standard practice for exploration and mining geologists to use it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that this will only give you surface information. It analyses what it can see. If you want to know what is inside the rock, you have to drill or break it.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If you want to know what is inside the rock without breaking it, you can use a CT scanner, but it only gives information on density. Inferring what the material is based on its density can be a challenging task and it is made easier if you have pre-existing information on what it could be. There are no portable CT scanners however (at least not hand-held). They can me mounted on trucks though.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;There are other methods, such as infrared, Raman, LIBS, etc etc.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The Mars Curiosity Rover has quite a lot of those &lt;a href=&quot;https://en.wikipedia.org/wiki/Curiosity_%28rover%29#Instruments&quot; rel=&quot;noreferrer&quot;&gt;instruments&lt;/a&gt; on board. It is essentially a semi-automated geologist exploring another planet.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-05-12T23:41:48.303" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19733" PostTypeId="1" CreationDate="2020-05-13T08:36:24.753" Score="3" ViewCount="167" Body="&lt;p&gt;I am new to climate science and have been learning the basic picture of the intertropical convergence zone (ITCZ) and how this leads to the predominant easterly &quot;trade winds&quot;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The picture that I have learned is the following. As the ITCZ is a belt of low surface pressure along the equator, air is drawn in from the north in the northern hemisphere and from the south in the southern hemisphere. Due to the coriolis effect, the southward winds in the northern hemisphere are deflected westward and the northward winds in the southern hemisphere are also deflected westward, with respect to the earth's reference frame. Thus the winds along the ITCZ blow westwards (i.e. Easterly winds). &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I also know that the ITCZ is not a perfect circle, and also moves around with the seasons, so that in the northern hemisphere summer it is predominantly in the northern hemisphere, and in the southern hemisphere summer it is predominantly in the southern hemisphere, and on an average day you might find parts of the belt in the northern hemisphere and parts in the southern hemisphere. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But then my basic picture breaks down. Indeed, if the ITCZ lies north of the equator, then the winds approaching from the north are deflected westwards, whilst winds approaching from the south are deflected &lt;em&gt;eastwards&lt;/em&gt;. So the trade winds just south of the ITCZ are now westerlies rather than traditional easterlies, and winds are converging at the ITCZ with opposing directions (and presumably rubbing against one another creating friction). A mirror situation holds with the ITCZ south of the equator.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My questions are:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1) Is my above reasoning correct / applicable to the atmosphere?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2) If so, what effects does this have on the properties of the ITCZ, and what are some examples of these effects on weather patterns? I am very happy for explanations as well as references to appropriate texts.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Many thanks!&lt;/p&gt;&#xA;&#xA;&lt;p&gt;A. &lt;/p&gt;&#xA;" OwnerUserId="20448" LastEditorUserId="20448" LastEditDate="2020-05-13T09:20:49.633" LastActivityDate="2021-02-10T09:08:40.607" Title="How does the changing seasons affect the large scale easterly flow of the ITCZ?" Tags="|meteorology|geophysics|climate|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="19734" PostTypeId="2" ParentId="19729" CreationDate="2020-05-13T14:34:54.160" Score="3" Body="&lt;p&gt;To piggyback on Gimelist's answer:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another important tool X-ray diffraction. XRD is used to determine crystalline structures. Specifically, XRD sees the dimensions of different crystals (and most &quot;rocks&quot; are crystalline). When used with the information that XRF or other elemental analyses produce, skilled operators can identify what &lt;em&gt;specific&lt;/em&gt; materials are present in the rock by comparing the XRD diffratograms to those of lab-grown pure crystals. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some applications of these analyses include identifying rock origins. XRF will tell you how much iron the rock has. But XRD will tell you if it's got Olivine or Pyrite in it; the implication being that Olivine implies volcanic origin and Pyrite suggests biological origin (and maybe there's coal or oil in the area). &lt;/p&gt;&#xA;" OwnerUserId="18763" LastActivityDate="2020-05-13T14:34:54.160" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19735" PostTypeId="1" CreationDate="2020-05-13T19:03:06.283" Score="4" ViewCount="371" Body="&lt;p&gt;Do some rocks, soils, sands or waters exist that contain fewer than one atom of gold per cubic meter or tonne of their mass?&lt;/p&gt;&#xA;" OwnerUserId="20454" LastEditorUserId="725" LastEditDate="2020-05-13T23:19:32.430" LastActivityDate="2020-06-14T13:01:20.113" Title="Are the precious metals (silver, gold, platinum) present everywhere throughout the Earth's crust at least in the trace quantities?" Tags="|geology|geochemistry|crust|economic-geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19736" PostTypeId="1" CreationDate="2020-05-13T22:05:42.970" Score="1" ViewCount="98" Body="&lt;p&gt;At &lt;a href=&quot;https://redd.it/gh282b&quot; rel=&quot;nofollow noreferrer&quot;&gt;r/rbi&lt;/a&gt;, u/A11edge asked&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Can anyone determine an hour when the photo was taken?&lt;/p&gt;&#xA;&lt;p&gt;The author of the photo is suspected of spraying pesticides during daytime (which is illegal because it causes death of thousands of bees).&lt;/p&gt;&#xA;&lt;p&gt;Location: somewhere in Poland&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aT5dQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aT5dQ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;XauManKib answered&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Judging by the photo, I can see three main aspects: the flowers, the shadows and the upper reflection of the Sun.&lt;/p&gt;&#xA;&lt;p&gt;Considering the colour of the sky and the overall light, this is the afternoon.&lt;/p&gt;&#xA;&lt;p&gt;The flowers in the picture are Cruciferae, and I thinks is white mustard, common in East Europe, that is flowering between April and May, this means that the sunset in Poland, is around 1930 hours and 2020 hours in that period.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Supported by the shadows, the angulation of the Sun is clear in the reflection present in the photo, that is raffigurating [I looked up on &lt;a href=&quot;https://en.wiktionary.org/wiki/raffigurare#Italian&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wiktionary&lt;/a&gt;], except flares, the Sun as [typo for &amp;quot;is&amp;quot;] 15 degrees over the horizon, or about 40 minutes before the sunset.&lt;/strong&gt;&#xA;The time in the photo is between 1850 and 1940 hours.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;I never visited Poland and don't know anything on it. But can someone explain boldened paragraph like I'm 5 in Simple English? How  deduce all this?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;There are &amp;quot;&lt;strong&gt;flares&lt;/strong&gt;&amp;quot;?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&amp;quot;&lt;strong&gt;the angulation of the Sun is clear in the reflection present in the photo&lt;/strong&gt;&amp;quot;? Can someone draw on the picture to indicate this?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;How deduce the Sun is 15 degrees over the horizon?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;How deduce &amp;quot;&lt;strong&gt;40 minutes before the sunset&lt;/strong&gt;&amp;quot;?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerDisplayName="user17042" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-10-11T08:04:45.470" Title="[How deduce from shadows, the angulation of the Sun that the Sun is 15 degrees over horizon?" Tags="|sun|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19737" PostTypeId="2" ParentId="19735" CreationDate="2020-05-13T23:19:13.117" Score="1" Body="&lt;p&gt;The average concentration of gold in Earth's crust is about 2 ppb (±0.5, depending who you're asking). This is about 2 milligrams Au per tonne of rock. It's not much, but it still equals about 6×10&lt;sup&gt;18&lt;/sup&gt; atoms, or 6 billion billion atoms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Seawater has on average 0.004 ppb of gold. This equals 4 micrograms Au per tonne of seawater. Much less, but still about 1×10&lt;sup&gt;16&lt;/sup&gt; atoms of gold, or 10 million billion atoms.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So to answer your question:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;...contain fewer than one atom of gold per cubic meter or tonne of&#xA;  their mass&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;The answer is a clear no.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Edit&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These seemingly huge numbers do not mean that there is a lot of gold in the rock. That 0.004 ppb of gold which means 10 million billion atoms, is still only 0.0000000004% of the rock. This is clearly a completely insignificant amount of gold. Nonetheless, this insanely tiny amount of gold still an insanely large amount of atoms of gold. There are a lot of atoms out there.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2020-05-15T12:56:13.507" LastActivityDate="2020-05-15T12:56:13.507" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19739" PostTypeId="2" ParentId="19736" CreationDate="2020-05-14T06:33:07.400" Score="1" Body="&lt;p&gt;If you look at the shadow of the tractor on the right side of the exhaust pipe you can see that this picture is taken in the early morning or a fairly short time before sunset.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is not possible to give you a good estimate of what time the picture is taken as this depends on the time of year.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the picture is taken in early april it is more than one hour before sunset and more than one hour after sunrise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the picture is taken in the middle of may it might be whitin one hour before sunset or one hour after sunrise.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastActivityDate="2020-05-14T06:33:07.400" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19740" PostTypeId="1" AcceptedAnswerId="19750" CreationDate="2020-05-14T07:24:52.090" Score="4" ViewCount="829" Body="&lt;p&gt;I can find several examples of Rossby waves, mainly atmospheric, moving towards East. Is it possible that they also move towards West?&lt;/p&gt;&#xA;" OwnerUserId="8396" LastActivityDate="2020-06-17T11:05:13.997" Title="How can oceanic Rossby waves move from East to West?" Tags="|oceanography|waves|dynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19741" PostTypeId="1" CreationDate="2020-05-15T04:53:29.443" Score="0" ViewCount="65" Body="&lt;p&gt;Am new to this. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I was reading &lt;em&gt;New Geopolitics of natural gas&lt;/em&gt; by Agnia and came across this paragraph : &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;because gas historically had been supplied primarily by land-based&#xA;  pipeline monopolies rather than by competing ship tankers moving in&#xA;  any direction across the seas, gas-importing countries have had to&#xA;  rely on a limited number of suppliers. As a result, until recently,&#xA;  many countries, especially in Central and Eastern Europe and the&#xA;  Caucasus, have been 100 percent dependent on a single gas pipeline, a&#xA;  single gas-producing country, and even a single company, such as the&#xA;  Russian gas giant Gazprom. Meanwhile, gas-producing countries such as&#xA;  Russia have likewise been dependent on a fixed set of pipeline export&#xA;  routes and consumers. Then, too, with other states serving as transit&#xA;  territories for the pipelines carrying gas from producing to importing&#xA;  countries, these territorially driven gas trade relationships have&#xA;  impacted national, regional, and international politics.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;Why are pipeline export routes considered fixed? Are they expensive? Does its erection damage the land in ways relevant to new routes or something? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the same time, I also wondered why don't gas producers make their own shippers instead of being depend on transite states? Because of the benefits of specialisation? Are they the exception; were they simply fast enough. &lt;/p&gt;&#xA;" OwnerUserId="20464" LastEditorUserId="14194" LastEditDate="2020-05-15T13:05:03.830" LastActivityDate="2020-05-15T14:53:56.143" Title="What does it mean that &quot;gas-producing countries such as Russia have likewise been dependent on a fixed set of pipeline export routes&quot;?" Tags="|oil-reserves|" AnswerCount="2" CommentCount="2" ClosedDate="2020-05-15T19:39:42.437" ContentLicense="CC BY-SA 4.0" />
  <row Id="19742" PostTypeId="2" ParentId="19741" CreationDate="2020-05-15T06:00:55.337" Score="2" Body="&lt;p&gt;Building a pipeline simply is an expensive undertaking. In Eastern Germany e.g. there's one built right now, the EUGAL-pipeline. It will be about 480 km long (check the English &lt;a href=&quot;https://www.eugal.de/fileadmin/downloads_eugal/factsheets/EUGAL_Factsheet_en_181206.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;fact sheet&lt;/a&gt;) and, according to the &lt;a href=&quot;https://www.bmwi.de/Redaktion/DE/Parlamentarische-Anfragen/2018/05-327-328.pdf?__blob=publicationFile&amp;amp;v=4&quot; rel=&quot;nofollow noreferrer&quot;&gt;governments response&lt;/a&gt; to a question by a member of parliament from May 2018 (in German only) those 480 km cost about 2,276 million Euro (see top of page 2 in the PDF). So, one kilometer of pipeline costs about 4.7 million Euros - yes, pipelines are expensive.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To be fair, labour cost in Germany is rather high, and if you check the following image you'll see that the pipeline is buried which I suppose increases the cost significantly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fVjdW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fVjdW.jpg&quot; alt=&quot;cranes lifting the pipeline into the trench&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.eugal.de/en/disclaimer/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Copyright 2015, GASCADE Gastransport GmbH&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Still, building a pipeline is not cheap - moneywise, timewise and when it comes to environmental impact.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Furthermore, a pipeline can have political implications. E.g. the &lt;a href=&quot;https://www.nord-stream.com/the-project/pipeline/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nord Stream 1 and 2&lt;/a&gt; pipelines which run from northwestern Russia (close to St. Petersburg) to northeastern Germany even made the US intervene. The old pipelines from Russia to Central Europe run through the Eastern European countries, most notably the Ukraine - and currently politics between Russia and the Ukraine are rather sour. So bypassing transit countries enforces the Russian position - which in turn &lt;a href=&quot;https://www.bbc.com/news/world-europe-50247793&quot; rel=&quot;nofollow noreferrer&quot;&gt;angered the US&lt;/a&gt; since they want to reduce Russian influence on Europe (and sell their own shale gas, but that's another issue).&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;To summarize: Pipelines are very expensive, and it also takes a great deal of negotiation (politically and environmentally) to build one. So yes, they are rather fixed.&lt;/p&gt;&#xA;" OwnerUserId="14194" LastActivityDate="2020-05-15T06:00:55.337" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19743" PostTypeId="2" ParentId="19741" CreationDate="2020-05-15T14:53:56.143" Score="0" Body="&lt;p&gt;In addition to answer #1 : Even in the US where there are not obstructions of international politics, There are always some protest groups who object to every possible pipeline route. One example, Aleska pipeline across Alaska, basically no towns or people involved, but it was delayed years by protests. The new pipe laid on the ground for over 3 years waiting on permits ;A whole new technology was developed to recondition the new pipe for construction. And shipping by the only other ( quantity) possibility , LNG tanker is more expensive , limited availability, and a relatively recent development .&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2020-05-15T14:53:56.143" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19744" PostTypeId="1" AcceptedAnswerId="19745" CreationDate="2020-05-15T23:51:22.017" Score="1" ViewCount="532" Body="&lt;p&gt;When a volcanic island first surfaces, I assume no vegetation can grow, as it probably only consists of volcanic rock.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;How would a volcanic island like Iceland that is far from any continent grow to have soil, and enough of it to grow forests?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it formed through hydraulic erosion?&lt;br&gt;&#xA;Is it brought from the ocean floor with the currents?&lt;br&gt;&#xA;Do aerial currents and birds bring it with them?&#xA;If it's something that only reaches the shore, how does it move inland?&lt;/p&gt;&#xA;" OwnerUserId="14561" LastEditorUserId="5259" LastEditDate="2020-05-18T22:35:07.613" LastActivityDate="2020-05-18T22:35:07.613" Title="How does fertile soil reach newborn volcanic islands?" Tags="|volcanology|soil|islands|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19745" PostTypeId="2" ParentId="19744" CreationDate="2020-05-16T10:04:16.750" Score="6" Body="&lt;p&gt;This image may serve as a base to illustrate the points from the question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;img src=&quot;https://eoimages.gsfc.nasa.gov/images/imagerecords/8000/8827/ISS017-E-06820_lrg.jpg&quot; alt=&quot;La Palma&quot;&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/La_Palma&quot; rel=&quot;noreferrer&quot;&gt;La Palma&lt;/a&gt;, Aridane Valley and Cumbre Vieja volcano:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On the left (north) one sees the incisions of erosion at the flank of Bejenado volcano. It formed between ~500 and ~400 ky ago. Volcanic activity has ceased and it is now slowly weathering down. In the center and right one sees the Aridane Valley and the Cumbre Vieja whith its picturesque cones. The Aridane Valley is an erosional structure formed by a series of landslides slightly earlier than the Bejenado. Cumbre Vieja is an active volcano, last eruption is Teneguia 1971 in the south, just out of the right of the image.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;On can distinguish several lava flows from historic and modern times by their darker colour. They are between ~70 and several hundred years old, but the whole island is built of such lavaflows, layer by layer (simplifying here). Wind, weather, insects and birds bring on pollen and seeds. Even on a fresh layer, after just a few months to years, pioneer plants like lichen will start to settle. Once exposed and solidified, the basalt starts to weather and erode. These processes form clay minerals, which release the nutrients to grow more and more plants and biocenoses, and so on. And basalt weathers quickly, releasing a lot of nutrients in relatively short time.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, yes, your asumptions are in principle on the right track. I'm not sure about the direct role of ocean currents here, and &lt;strong&gt;soil is not brought in by the wind&lt;/strong&gt; (at least not in decisive amounts, more or less dust from a nearby continent will allways be in the air), &lt;strong&gt;it forms through weathering&lt;/strong&gt; of the basalt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Weathering and erosion are very complex. Obviously, chemical and physical processes play an initial role; once plants have settled, their roots cause physical changes, bacteria from decay amplify chemical processes, and so on.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This is mostly textbook knowledge of the general process. For more specific information about the processes one can read up more on basalt weathering, chemical and physical erosion, &lt;a href=&quot;https://en.wikipedia.org/wiki/Pioneer_species&quot; rel=&quot;noreferrer&quot;&gt;pioneer plants&lt;/a&gt;, and so on.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-05-16T18:42:11.440" LastActivityDate="2020-05-16T18:42:11.440" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19749" PostTypeId="1" CreationDate="2020-05-17T17:37:49.963" Score="1" ViewCount="41" Body="&lt;p&gt;I'm looking for a &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; measuring probe (analog current output, digital out: RS232/485 - probe will be connected and transferring real time data to the data logger) that would operate up to 150 °C (hot air sucked out from the heated column which is highly concentrated by &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt;).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Another &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; probe should measure (rather control) trace amount of &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; after it's separated from the exhaust gas (small scale experimental boiler burning coal) - operating temp. approx. 75 °C.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have found tons of probes, but all of them measure up to + 60/65 °C. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Do you have any experiences with such probes?&lt;/p&gt;&#xA;" OwnerUserId="20469" LastActivityDate="2020-05-17T17:37:49.963" Title="CO2 probe measuring at temperatures up to 150 °C" Tags="|co2|carbon-cycle|" AnswerCount="0" CommentCount="7" ClosedDate="2020-05-19T11:29:33.073" ContentLicense="CC BY-SA 4.0" />
  <row Id="19750" PostTypeId="2" ParentId="19740" CreationDate="2020-05-17T18:01:52.233" Score="6" Body="&lt;p&gt;Yes it is. In fact Rossby waves always move westward in the absence of a zonal mean flow. Before going into detail lets try to explain this qualitatively. In a barotropic fluid the absolute vorticity is conserved. The absolute vorticity is composed of the relative vorticity &lt;span class=&quot;math-container&quot;&gt;$\zeta$&lt;/span&gt; and the planetary vorticity &lt;span class=&quot;math-container&quot;&gt;$f$&lt;/span&gt; (&lt;span class=&quot;math-container&quot;&gt;$f$&lt;/span&gt; is also called the Coriolis parameter). &lt;span class=&quot;math-container&quot;&gt;$\zeta$&lt;/span&gt; is the rotation of the fluid as you would observe on earth. &lt;span class=&quot;math-container&quot;&gt;$\zeta + f$&lt;/span&gt; is the rotation of the fluid as someone from space would observe. Conservation means that the sum &lt;span class=&quot;math-container&quot;&gt;$\zeta + f$&lt;/span&gt; must always stay the same no matter where a fluid parcel moves. I.e. &lt;span class=&quot;math-container&quot;&gt;$D(\zeta + f)/D t = 0.$&lt;/span&gt; Notice that &lt;span class=&quot;math-container&quot;&gt;$f = 2 \Omega \sin \varphi$&lt;/span&gt; increases the further we move away from the equator. &lt;span class=&quot;math-container&quot;&gt;$\Omega$&lt;/span&gt; is earths angular frequency and &lt;span class=&quot;math-container&quot;&gt;$\varphi$&lt;/span&gt; is the latitude.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now imagine a line of connected fluid parcels that is initially at rest (horizontal line in the figure below). Lets say on the northern hemisphere at a line of constant latitude. If we displace the parcels to the sine like line, the following happens: If we move northwards to the pole the planetary vorticity increases (&lt;span class=&quot;math-container&quot;&gt;$f$&lt;/span&gt; increases), but if absolute vorticity is conserved, &lt;span class=&quot;math-container&quot;&gt;$\zeta$&lt;/span&gt; must decrease. If the parcels were initially at rest (as observed by someone standing on earth) &lt;span class=&quot;math-container&quot;&gt;$\zeta$&lt;/span&gt; is now negative - inducing a clockwise rotation. If we displace parcels southward the converse happens. &lt;span class=&quot;math-container&quot;&gt;$f$&lt;/span&gt; decreses and &lt;span class=&quot;math-container&quot;&gt;$\zeta$&lt;/span&gt; increases, inducing an anti-clockwise rotation. If we move even further in time the rotation induced before will translate the wave to the sine like dashed wave. Think of the arrows in the figure as &quot;pushing&quot; the solid sine like line to the dashed sine like line. This describes a motion of the wave from east to west! &lt;a href=&quot;https://i.stack.imgur.com/BVU1M.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BVU1M.png&quot; alt=&quot;Rossby waves as a consequence of absolute vorticity conservation&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is needed to make the wave move eastward? Imagine the horizontal line moves towards the east (i.e. we have a zonal flow), the wave itself will move eastward if the zonal flow is faster than than the westward movement of the phase which I described above. The details are a little more complicated but I will state them below.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Lets take a look at the details. Maybe the simplest setting to study Rossby waves is based on the barotropic vorticity equation (BVE) which describes the flow of incompressible, non-divergent, constant density flow on a rotating sphere. If you are not interested in the derivation here just take a look at the part denoted &quot;&lt;strong&gt;Dispersion relation&lt;/strong&gt;&quot;, which will describe the phenomenon.  The relative vorticity &lt;span class=&quot;math-container&quot;&gt;$\zeta$&lt;/span&gt; is given by &lt;span class=&quot;math-container&quot;&gt;$\zeta = \partial v / \partial x - \partial u/ \partial y$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$v$&lt;/span&gt; is the the northward component of the velocity and &lt;span class=&quot;math-container&quot;&gt;$u$&lt;/span&gt; is the eastward component of the velocity. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The equation of motion (BVE) is given by:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\left( \frac{\partial }{\partial t} + u \frac{\partial }{\partial x} + v \frac{\partial}{\partial y}\right)\zeta + \beta v = 0.$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This equation is equivalent to &lt;span class=&quot;math-container&quot;&gt;$D(\zeta + f)/D t = 0$&lt;/span&gt; as described above. The first term (&lt;span class=&quot;math-container&quot;&gt;$\partial \zeta/\partial t$&lt;/span&gt;) is the local change of relative vorticity, followed the advection of relative vorticity and finally there is the advection of planetary vorticity &lt;span class=&quot;math-container&quot;&gt;$v\beta$&lt;/span&gt; (&lt;span class=&quot;math-container&quot;&gt;$\beta = \partial f / \partial y$&lt;/span&gt;), which is the contribution to the rotation of the fluid by the earth itself. Solutions to this equation can be interpreted as Rossby waves. However to admit solutions including zonal flow we must linearize the equation about a basic state plus perturbations. We do this by letting &lt;span class=&quot;math-container&quot;&gt;$u = \overline{u} + u'$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$v = v'$&lt;/span&gt;. So we have a zonal mean flow &lt;span class=&quot;math-container&quot;&gt;$\overline{u}$&lt;/span&gt; and perturbations &lt;span class=&quot;math-container&quot;&gt;$u'$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$v'$&lt;/span&gt;. The perturbation vorticity is then &lt;span class=&quot;math-container&quot;&gt;$\zeta' = \partial v' / \partial x - \partial u'/ \partial y $&lt;/span&gt;. Introducing a stream function &lt;span class=&quot;math-container&quot;&gt;$\psi$&lt;/span&gt; that is related to the relative vorticity by &lt;span class=&quot;math-container&quot;&gt;$\nabla^2 \psi = \zeta'$&lt;/span&gt; we can write the linearized BVE as &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\left(\frac{\partial}{\partial t} + \overline{u} \frac{\partial }{\partial x} \right) \nabla^2 \psi + \beta \frac{\partial \psi}{\partial x} = 0.$&lt;/span&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the equation above terms involving products of perturbation (e.g. &lt;span class=&quot;math-container&quot;&gt;$u'v'$&lt;/span&gt;) where neglected because they are assumed to be small (something small squared is even smaller).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Dispersion relation&lt;/strong&gt;:&#xA;A wave like solution to the perturbed BVE is given by &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\psi = Re(\psi_0 e^{i \phi})$&lt;/span&gt;,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$\psi_0$&lt;/span&gt; determines the maximum amplitude and the phase &lt;span class=&quot;math-container&quot;&gt;$\phi = kx + ly - \nu t $&lt;/span&gt;. &lt;span class=&quot;math-container&quot;&gt;$k,l$&lt;/span&gt; are zonal, meridional wavevectors and &lt;span class=&quot;math-container&quot;&gt;$\nu$&lt;/span&gt; is the frequency of the wave. Substituting the proposed solution into the perturbed BVE yields the &lt;strong&gt;dispersion relation&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\nu = \overline{u}k - \frac{\beta k}{k^2+l^2}$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Recall from elementary physics that the zonal phase speed is given by&lt;span class=&quot;math-container&quot;&gt;$ c = \nu/k$&lt;/span&gt;. This allows to write the dispersion relation in the desired form, answering your question:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$c = \overline{u}- \frac{\beta}{k^2+l^2}$&lt;/span&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Notice that &lt;span class=&quot;math-container&quot;&gt;$c$&lt;/span&gt; determines whether the Rossby wave moves eastward (c&gt;0) or westward (c&amp;lt;0). In the case of &lt;span class=&quot;math-container&quot;&gt;$\overline{u} = 0$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$c$&lt;/span&gt; is negative and therefore, the wave moves from east to west. In fact a Rossby wave can only travel from west to east in the presence of a zonal flow that is also directed eastward. More precisely if &lt;span class=&quot;math-container&quot;&gt;$\overline{u}&amp;gt;\beta/(k^2+l^2)$&lt;/span&gt;. This also explains the answer of gansub: long waves have small wave numbers, therefore &lt;span class=&quot;math-container&quot;&gt;$\beta/(k^2+l^2)$&lt;/span&gt; is greater compared to smaller waves. Thus, it is more likely for the waves to travel westward.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My answer can be found almost identically in Holton, Hakim - Dynamic Meteorology, 5th edition, page 161 onwards. So credit the book rather than me.&lt;/p&gt;&#xA;" OwnerUserId="18833" LastEditorUserId="18833" LastEditDate="2020-06-17T11:05:13.997" LastActivityDate="2020-06-17T11:05:13.997" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19751" PostTypeId="1" CreationDate="2020-05-17T21:23:27.190" Score="1" ViewCount="67" Body="&lt;p&gt;While looking at this photo of a 24-hour clock: &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/6/61/Greenwich_clock_1-manipulated.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://upload.wikimedia.org/wikipedia/commons/6/61/Greenwich_clock_1-manipulated.jpg&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;... it struck me that, maybe, it could be seen as a visual representation of how the sun &quot;travels&quot; (from our perspective) &quot;around&quot; the Earth, here seen &quot;from the side&quot; from space.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But I'm not sure it holds up. Is this accurate? I can almost swear that I've seen clocks where the &quot;hour dial&quot; is a sun, which would further hint at this.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this is the case, I find it very fascinating and it will make me look at clocks in a whole new way. (Sadly, all the ones I've ever seen in real life have been 12-hour ones, so this visual representation cannot hold up for those.)&lt;/p&gt;&#xA;" OwnerUserId="20471" LastActivityDate="2020-05-17T21:23:27.190" Title="Does the hour thingie on a 24-hour clock represent the apparent &quot;motion&quot; of the Sun &quot;around&quot; the Earth?" Tags="|sun|time|" AnswerCount="0" CommentCount="8" ClosedDate="2020-05-18T12:42:07.850" ContentLicense="CC BY-SA 4.0" />
  <row Id="19752" PostTypeId="1" CreationDate="2020-05-18T03:06:49.207" Score="3" ViewCount="331" Body="&lt;p&gt;Good afternoon. Inside the creation of the synthetic seismogram some softwares have the option to run what is called &quot;sonic calibration&quot; or &quot;checkshot calibration&quot;. I have some questions:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1)why some softwares consider that the sonic should be calibrated while others consider the checkshot should be calibrated?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2)what is the interpretation of a positive drift curve and a negative drift curve?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;3)According to my research, in order to apply drift correction, you should apply a smoothing to the drift curve. In the case of the softwares that apply checkshot calibration, the idea is to use the sonic data points to infill the checkshot. Also you have 3 curves in one log track:the original sonic log, the original checkshot and the calibrated checkshot. You then have another track with two drift curves: a fixed one, that represent the difference, in time value,between the original  checkshot and the original sonic log a a movable drift curve. In this curve,if apply a lot of smoothing, the corrected checkshot curve will be more similar to the original sonic curve. If you apply a small smoothing, the calibrated checkshot curve will be more similar to the original checkshot curve.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is the idea that the calibrated curve to make it more similar to the original sonic curve, the original checkshot curve or something in between?why?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;4)Similar to question 3, how does this apply in case you do a sonic calibration?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;5)Are there big consequences of not doing checkshot/sonic calibration?which ones?&lt;/p&gt;&#xA;" OwnerUserId="20473" LastActivityDate="2021-07-30T16:00:45.040" Title="Construction of a drift curve in the well tie calibration and how to interpret it?. Sonic calibration vs checkshot calibration" Tags="|geophysics|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19754" PostTypeId="1" AcceptedAnswerId="19755" CreationDate="2020-05-20T18:45:30.597" Score="6" ViewCount="1362" Body="&lt;p&gt;I am trying to understand how prevailing winds and jet stream currents are formed and how they are varying in speed and direction.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When looking at different wind speeds at different altitudes on &lt;a href=&quot;https://earth.nullschool.net&quot; rel=&quot;noreferrer&quot;&gt;earth.nullschool.net&lt;/a&gt; I noticed that the height is expressed in hectoPascals (10hPa, 70hPa, 250hPa, 1000hPa) instead of feets or meters . &lt;/p&gt;&#xA;&#xA;&lt;p&gt;What is the explanation of choosing pressure for expresing height instead of another unit of length ?&lt;/p&gt;&#xA;" OwnerUserId="20490" LastActivityDate="2020-12-08T14:44:49.363" Title="What is the explanation of using pressure units (hPa) to express height when dealing with wind speeds?" Tags="|meteorology|atmosphere|wind|pressure|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19755" PostTypeId="2" ParentId="19754" CreationDate="2020-05-20T22:38:24.920" Score="14" Body="&lt;p&gt;There are several reasons. From the theoretical point of view it is beneficial to use isobaric coordinates, due to the vanishing density in the equations of motion. While in cartesian coordinates the wind is determined by the pressure gradient in isobaric coordinates the wind is determined by the geopotential gradient. The geopotential is defined by &lt;span class=&quot;math-container&quot;&gt;$\Phi = gz$&lt;/span&gt;. In the hydrostatic relation &lt;span class=&quot;math-container&quot;&gt;$p = \rho g z$&lt;/span&gt; we can relpace &lt;span class=&quot;math-container&quot;&gt;$gz = \Phi$&lt;/span&gt; and therefore any term containing &lt;span class=&quot;math-container&quot;&gt;$p/\rho = \Phi$&lt;/span&gt;. The geostrophic wind relation for example differ as follows:&lt;/p&gt;&#xA;&lt;p&gt;Pressure coordinates: &lt;span class=&quot;math-container&quot;&gt;$\vec{V_g} = \frac{1}{f} \vec{k} \times \nabla \Phi$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Cartesian coordinates: &lt;span class=&quot;math-container&quot;&gt;$\vec{V_g} = \frac{1}{\rho f} \vec{k} \times \nabla p$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Notice the density as an additional variable in the latter formula.&lt;/p&gt;&#xA;&lt;p&gt;Another reason arises historically. The vertical structure of the atmosphere could only be measured using balloons or radiosondes until around the seventies when satellites became an additional source of information. Until today radiosondes provide the most detailed profile of a vertical slice in the atmosphere. Radiosondes can not measure height in meter or feet but they can measure pressure. Also GPS is not be the best alternative. While it is quite accurate regarding the horizontal position it lacks accuracy in the vertical compared to pressure measurements.&lt;/p&gt;&#xA;&lt;p&gt;Edit:&#xA;I forgot one of the most important aspects: Looking at pressure surfaces also allows us to compare heights in a more meaningful way. What we experience as weather happens to 99% within the troposphere. However, height of the tropopause varies a lot from poles (~9km) to equator (~16km). Looking at a pressure level allows us to make sure the mass of air above that level is approximately the same everywhere and thus makes variables comparable. Note that comparing what happens at 12 km altitude in the tropics to 12 km altitude at the poles does not make sense at all, because at the poles we are already dealing with the stratosphere, while in the tropics we are still way below the tropopause. Staying on a pressure level ensures that we take these differences into account.&lt;/p&gt;&#xA;" OwnerUserId="18833" LastEditorUserId="18833" LastEditDate="2020-12-08T14:44:49.363" LastActivityDate="2020-12-08T14:44:49.363" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19756" PostTypeId="1" AcceptedAnswerId="19758" CreationDate="2020-05-21T04:05:13.023" Score="3" ViewCount="2197" Body="&lt;p&gt;In many articles online, geologists and geographers have described and depicted the theorized locations of all our continental plates with great detail and illustration, providing pictures, time-lapse videos, etc. as per Wegener's theory. But nowhere have I found online any article, paper, illustration, picture, or even a single comment, mention, or note talking about our continents' positions 10000 years ago, AKA, when the last ice age was just getting over. So please can someone answer this?&lt;/p&gt;&#xA;" OwnerUserId="20493" LastActivityDate="2020-05-21T05:45:51.490" Title="What was the Earth's continent's positions 10000 years ago, or 11700 years ago, AKA when the late Pleistocene epoch was coming to an end?" Tags="|geology|plate-tectonics|crust|continent|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19757" PostTypeId="2" ParentId="17779" CreationDate="2020-05-21T05:25:17.723" Score="1" Body="&lt;p&gt;I think what you are asking is there a way to do a research project that would look for a correlation between number of dust devils and tornadoes.  Dust devils, being very local phenomena, are not tracked (as far as I know).  So finding the data would be your first challenge.  Even if you could get a dataset of dust devil occurrence you would have the challenge of demonstrating that you do not have a &lt;a href=&quot;https://www.tylervigen.com/spurious-correlations&quot; rel=&quot;nofollow noreferrer&quot;&gt;spurious correlation&lt;/a&gt;.  This would be especially hard since to most observers these are completely different with one being found only in deserts and the other being associated with thunderstorms that are the result of convection currents moving water vapor up into higher levels of the atmosphere.  Don't look to statistics to test your hypothesis. I think you need to go deeper into both phenomena. Find a mechanism that explains why they would be linked. Then do research to see how often the proposed mechanism is found when tornadoes (or dust devils) are found.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2020-05-21T05:25:17.723" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19758" PostTypeId="2" ParentId="19756" CreationDate="2020-05-21T05:45:51.490" Score="7" Body="&lt;p&gt;The reason that you have not seen any diagram showing the position of the continents 10K years before present (ybp) is that the plates move so slowly that there would not be a perceptual difference on the scale of a world map. The Atlantic is &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007GC001743&quot; rel=&quot;noreferrer&quot;&gt;spreading&lt;/a&gt; about a half centimeter per year. So 10,000 years will have moved Europe away from North America by 5000 cm, or 50 meters.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;An additional reason is that most models of continental drift have the sub-oceanic magnetic banding due to &lt;a href=&quot;https://en.wikipedia.org/wiki/Geomagnetic_reversal&quot; rel=&quot;noreferrer&quot;&gt;geomagnetic reversals&lt;/a&gt; as their guide for &quot;recent&quot; positions of the plates.  The latest geomagnetic reversal, the Brunhes–Matuyama reversal, occurred 780K ybp.  This is long before your 10K ybp point of interest and so any interpolated data would be suspect.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2020-05-21T05:45:51.490" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19759" PostTypeId="2" ParentId="19483" CreationDate="2020-05-21T08:09:21.363" Score="0" Body="&lt;p&gt;NMO stretch and associated mathematical relation &#xA;i.e. &lt;span class=&quot;math-container&quot;&gt;$$ \frac{\Delta f}{f} = \frac{\Delta T_{NMO}}{T_0}  $$&lt;/span&gt;&#xA;are precisely explained in the book- &lt;a href=&quot;https://wiki.seg.org/wiki/Seismic_Data_Analysis&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seismic Data Analysis by Yilmaz&lt;/a&gt;. &#xA;Mathematical part can be found in &lt;a href=&quot;https://wiki.seg.org/wiki/Topics_in_moveout_and_statics_corrections&quot; rel=&quot;nofollow noreferrer&quot;&gt;Appendix C2&lt;/a&gt; &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The book is freely available.!&lt;/p&gt;&#xA;" OwnerUserId="5413" LastActivityDate="2020-05-21T08:09:21.363" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19761" PostTypeId="2" ParentId="19483" CreationDate="2020-05-21T13:24:47.727" Score="0" Body="&lt;p&gt;This is an important question - however, it has been asked and answered (with different content compared to above) &lt;a href=&quot;https://earthscience.stackexchange.com/questions/12635/what-is-seismic-stretch-in-geophysical-method/15591#15591&quot;&gt;here&lt;/a&gt;. Be that as it may, I think you should certainly compare what's been provided here to the link (and other resources too!).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'll further supplement everything you can find with some insight that's helped me understand what happens with the apparent &quot;stretch&quot; when NMO-correction is applied to CDP(common depth point), CMP(common midpoint), and/or CIP(common image point) gathers (beyond the scope of this question).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;When you see the classic equation and image referenced by @Eric, think to yourself: &quot;What happens to the &lt;em&gt;t&lt;/em&gt; term as &lt;em&gt;x&lt;/em&gt; (geophones/hydrophones apart from and further away from the first sensor) increases?&quot; You can play with this idea with different variables and constants, sample-by-sample. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Remember, that both the &lt;em&gt;t&lt;/em&gt;&lt;sub&gt;0&lt;/sub&gt; and &lt;em&gt;v&lt;/em&gt; should remain constant for a correct stacking velocity for a single-impedance model (i.e. 2 layers). This becomes slightly more complicated with more layering, dipping horizons, and anisotropy. Don't let the latter part of this paragraph distract you from the main and simple idea you've posed though. The more complicated, real-world stuff can be handled later!&lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2020-05-21T13:24:47.727" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19763" PostTypeId="1" CreationDate="2020-05-23T16:47:09.463" Score="2" ViewCount="377" Body="&lt;p&gt;The reason behind the non- formation of dewdrops on a cloudy night is the non-attainment of below dew point temperatures. It happens as the outgoing longwave radiation (OLR) is not allowed to escape due to cloud cover. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is: How the clouds do this, exactly? Do they absorb OLR or they just reflect it back to earth therby not allowing the earth temperature to go below dew point? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;My second question is about the formation of dew drops on a clear night. Why do the greenhouse gases that are implicated for global warming allow OLR to pass through to space?  Do the greenhouse gases somehow become transparent to OLR during nighttime on clear nights?&lt;/p&gt;&#xA;" OwnerUserId="18396" LastEditorUserId="6467" LastEditDate="2020-05-23T21:00:06.100" LastActivityDate="2020-05-25T07:06:27.423" Title="Why don't dewdrops form on a cloudy night?" Tags="|atmosphere|greenhouse-gases|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19764" PostTypeId="1" CreationDate="2020-05-24T10:46:16.493" Score="2" ViewCount="82" Body="&lt;p&gt;These limestone-clay rocks are very common in the Alps, they come from weather changes. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;How many years does it take to make one of the rock bands? 7 years, equivalent to an el-nino type event? 1000 years? 20,000 years? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xQmMR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xQmMR.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&#xA;From the wiki page which is only in French: &lt;a href=&quot;https://fr.wikipedia.org/wiki/Formation_marno-calcaire&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://fr.wikipedia.org/wiki/Formation_marno-calcaire&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3315" LastActivityDate="2021-01-20T07:47:13.173" Title="What is the time period of these chalk/clay layers?" Tags="|rocks|fossils|stratigraphy|limestone|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19765" PostTypeId="2" ParentId="19764" CreationDate="2020-05-24T10:54:12.180" Score="2" Body="&lt;p&gt;The layers correspond to thousands of years, i.e. 23,000 years in the Danien timeline: &lt;a href=&quot;https://i.stack.imgur.com/Rzaen.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Rzaen.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The page sais that there is a variation of 23,000 for precession of the equinoxes and 100,000 for variation of ellipticity. &lt;a href=&quot;https://planet-terre.ens-lyon.fr/image-de-la-semaine/Img421-2013-04-15.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://planet-terre.ens-lyon.fr/image-de-la-semaine/Img421-2013-04-15.xml&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2021-01-20T07:47:13.173" LastActivityDate="2021-01-20T07:47:13.173" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19766" PostTypeId="2" ParentId="19763" CreationDate="2020-05-24T16:40:41.440" Score="1" Body="&lt;p&gt;Water vapor is an extremely potent greenhouse gas. But, like all greenhouse gases, water vapor is transparent to some portions of the thermal infrared, and even where absorptivity is relatively high, a thick column of water vapor is needed to absorb almost all of the incoming thermal radiation. Liquid water and ice are much better, and much less selective absorbers of thermal radiation. The following graph shows the absorption coefficient for water vapor (green), liquid water (red) and ice (blue), from 667 nm to 200 μm.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;[&lt;img src=&quot;https://i.stack.imgur.com/sWCyf.gif&quot; alt=&quot;Graph of water sorption coefficient for water vapor (green), liquid water (red) and ice (blue), from 667 nm to 200 μm.[1]&quot;&gt;&#xA;&lt;sup&gt;Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Water_infrared_absorption_coefficient_large.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/File:Water_infrared_absorption_coefficient_large.gif&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that at around 10 μm (the peak of 290 kelvin thermal radiation), liquid water and ice are much stronger absorbers than is water vapor. The absorption coefficient for liquid water and for water ice is about 70000 reciprocal meters. This means that a typical cloud droplet (10 to 15 micrometers across) absorbs one half to two thirds of incoming infrared radiation that impinges upon the droplet. While clouds are mostly air and water vapor, the tiny portion of a cloud that is in the form of small droplets of liquid or small ice particles makes clouds a very potent thermal blanket.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-05-24T16:40:41.440" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19767" PostTypeId="1" CreationDate="2020-05-24T21:40:32.207" Score="1" ViewCount="345" Body="&lt;p&gt;I am working on CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; by WRF-CHEM, for providing my anthropogenic emission from Edgar data base, I'm going to use the Prep_chem_source App.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I would like to use Edgar data emission (as my anthropogenic emission) for CO&lt;sub&gt;2&lt;/sub&gt;-CH&lt;sub&gt;4&lt;/sub&gt; and simulate these gasses by WRF-CHEM.&#xA;due to the Prep_chem_source instruction, I have done bellow steps:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;I consider chem_opt=0 and run the &lt;code&gt;./real.exe&lt;/code&gt;&lt;/li&gt;&#xA;&lt;li&gt;Run &lt;code&gt;./prep_chem_source.exe&lt;/code&gt;&lt;/li&gt;&#xA;&lt;li&gt;Link the output of files of step 2, to my em_real&#xA;directory (emissopt3_d01,...)&lt;/li&gt;&#xA;&lt;li&gt;Change namelist.input  chem_opt in to 17, chem_opt=17&lt;/li&gt;&#xA;&lt;li&gt;Run &lt;code&gt;./convert_emiss.exe&lt;/code&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;But &lt;code&gt;./convert&lt;/code&gt; doesn't make wrfchemi_d01 ,wrffirechemi_d02,...&#xA;what shall I do to have E_CO2, E_CH4,...as my anthropogenic emission from Edgar, using prep_source?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It is a part of my name list:&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;&amp;amp;time_control&#xA;run_days                 = 0,&#xA;run_hours                = 30,&#xA;run_minutes              = 0,&#xA;run_seconds              = 0,&#xA;start_year               = 2007, 2007,&#xA;start_month              = 08, 08,&#xA;start_day                = 1,  1,&#xA;start_hour               = 18,       18,&#xA;start_minute             = 00,       00,&#xA;start_second             = 00,       00,&#xA;end_year                 = 2010, 2010,&#xA;end_month                = 08, 08,&#xA;end_day                  = 03, 03,&#xA;end_hour                 = 00,      00,&#xA;end_minute               = 00,       00,&#xA;end_second               = 00,       00,&#xA;input_from_file          = .true.,   .true.,&#xA;interval_seconds         = 21600,&#xA;history_outname          = &quot;wrfout&amp;lt;domain&amp;gt;_&amp;lt;date&amp;gt;&quot;,&#xA;frames_per_auxinput5     = 2,    2,&#xA;auxinput5_inname         = &quot;wrfchemi_d&amp;lt;domain&amp;gt;_&amp;lt;date&amp;gt;&quot;,&#xA;auxinput5_interval_m     = 1440,  1440,&#xA;io_form_auxinput5        = 2,&#xA;frames_per_auxinput7     = 2,    2,&#xA;auxinput7_inname         = &quot;wrffirechemi_d&amp;lt;domain&amp;gt;_&amp;lt;date&amp;gt;&quot;,&#xA;auxinput7_interval_m     = 1440,  1440,&#xA;io_form_auxinput7        = 2,&#xA;history_interval         = 60,      60,&#xA;frames_per_outfile       = 1000,     1000,&#xA;restart                  = .false.,&#xA;write_hist_at_0h_rst     = .true.,&#xA;restart_interval         = 360,&#xA;io_form_history          = 2,&#xA;io_form_restart          = 2,&#xA;io_form_input            = 2,&#xA;io_form_boundary         = 2,&#xA;debug_level              = 0,&#xA;/&#xA;&amp;amp;physics&#xA;mp_physics               = 10,        10,  ! 3,        3,&#xA;ra_lw_physics            = 1,        1,&#xA;ra_sw_physics            = 1,        1,&#xA;radt                     = 30,       2,&#xA;sf_sfclay_physics        = 1,        1,&#xA;sf_surface_physics       = 2,        2,&#xA;bl_pbl_physics           = 8,        8,  ! 1,        1,&#xA;bldt                     = 0,        0,&#xA;cu_physics               = 3,        3,  ! 3,        3,&#xA;cudt                     = 0,        0,  ! 5,        5,&#xA;isfflx                   = 1,&#xA;ifsnow                   = 1,&#xA;icloud                   = 1,&#xA;surface_input_source     = 1,&#xA;num_soil_layers          = 4,&#xA;! sf_urban_physics       = 0,    0,&#xA;cu_diag                  = 1,  1,&#xA;cugd_avedx               = 1,    !  3,&#xA;cu_rad_feedback          = .true.,   .true.,&#xA;maxiens                  = 1,&#xA;maxens                   = 3,&#xA;maxens2                  = 3,&#xA;maxens3                  = 16,&#xA;ensdim                   = 144,&#xA;/&#xA;&#xA;&amp;amp;chem&#xA; chem_opt                            = 17,  17,&#xA; vertmix_onoff                       = 1,  1,&#xA; have_bcs_chem                       = .true., .true.,&#xA;!! have_bcs_tracer                     = .false., .false.,&#xA; chem_in_opt                         = 0,  0,&#xA; term_opt                            = &quot;CH4_termite_OW&quot;, &quot;CH4_termite_OW&quot;,&#xA; emiss_inpt_opt                      = 16,  16,&#xA; emiss_opt                           = 17, 17,&#xA; chem_conv_tr  &#xA;! bb_opt_ghg                          = 0, 0,&#xA; biomass_burn_opt                    = 5,   5, ! 0,  0,&#xA; !plumerisefire_frq                   = 60, 60,&#xA; io_style_emissions                  = 2,&#xA; kemit                               = 1,&#xA; bioemdt                             = 30, 30,&#xA; photdt                              = 30,  30,&#xA; chemdt                              = 1.,  1.,&#xA; phot_opt                            = 0,   0,&#xA; bio_emiss_opt                       = 1,   1,&#xA; conv_tr_wetscav                     = 0,   0,&#xA; gas_bc_opt                          = 0,   0,&#xA; gas_ic_opt                          = 0,   0,&#xA; aer_bc_opt                          = 0,   0,&#xA; aer_ic_opt                          = 0,   0,&#xA; gaschem_onoff                       = 0,   0,&#xA; aerchem_onoff                       = 0,   0,&#xA; wetscav_onoff                       = 0,   0,&#xA; cldchem_onoff                       = 0,   0,&#xA; aer_ra_feedback                     = 0,   0,&#xA; vprm_opt                            = &quot;VPRM_table_TROPICS&quot;, &quot;VPRM_table_TROPICS&quot;,&#xA; gas_drydep_opt                      = 0,   0,&#xA;/&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="18881" LastEditorUserId="18881" LastEditDate="2020-05-25T07:39:04.663" LastActivityDate="2021-05-07T03:13:35.057" Title="Providing Edgar emission using prep_chem_source for tracers (CO2-CH4)" Tags="|meteorology|climate-change|climate-models|wrf|wrf-chem|" AnswerCount="0" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="19768" PostTypeId="2" ParentId="19763" CreationDate="2020-05-25T07:06:27.423" Score="2" Body="&lt;p&gt;Clouds absorb thermal radiation and re-emit it, so that some of it comes back towards the Earth (&lt;a href=&quot;https://www.wave3.com/2019/09/27/behind-forecast-how-clouds-affect-temperatures/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Behind the Forecast: How clouds affect temperatures&lt;/a&gt;). During the day this warming effect is balanced by the cooling effect of blocking out the sunlight. They don't strictly speaking stop the formation of dew, but they make it less likely.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;In the words of NASA's Climate for Kids pages, &quot;&lt;a href=&quot;https://climatekids.nasa.gov/cloud-climate/&quot; rel=&quot;nofollow noreferrer&quot;&gt;It’s sort of like clouds are wrapping Earth in a big, warm blanket&lt;/a&gt;.&quot;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The 2nd question is about the effectiveness of greenhouse gases, and why we still get dew at night with all the extra greenhouse gases (GHGs) in the atmosphere. There are two parts to this. Firstly, the GHGs are not as effective as clouds when it comes to blocking the transmission of thermal radiation to space: they absorb in spectral bands related to the vibrational modes of the molecules in the gases, and there are gaps in these bands (&quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Infrared_window&quot; rel=&quot;nofollow noreferrer&quot;&gt;windows&lt;/a&gt;&quot;) which allow radiation to escape to space. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Secondly, dew formation depends not only on the temperature at night, but also on the near-surface humidity. The increase is GHGs is, as we know, warming the Earth and this also leads to an increase in the amount of water vapour in the atmosphere, because warmer air can carry more water. To get dew formation we need a change in the temperature between night and day -- and GHGs don't contribute directly to this. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;There is an indirect effect which we see in &lt;a href=&quot;https://www.sciencedaily.com/releases/2016/03/160310080530.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;nights getting warmer faster than days&lt;/a&gt;. There are several recent studies looking at the vapour pressure deficit (VPD) and showing an increase due to GHGs (e.g. &lt;a href=&quot;https://www.scopus.com/record/display.uri?eid=2-s2.0-85013250186&amp;amp;origin=inward&amp;amp;txGid=f37d9022f0b4947e9f26a55528f6735f&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ficklin and Novick&lt;/a&gt;) -- VPD is a measure of the dryness of the air and an increases means less dew (though I have not found a reference that give direct evidence of reductions in the amount of dew). This drying of the night-time may also contribute to reduced harvests (&lt;a href=&quot;https://reader.elsevier.com/reader/sd/pii/S1360138520300522&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sadok and Jagadish&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="17518" LastActivityDate="2020-05-25T07:06:27.423" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19769" PostTypeId="2" ParentId="19696" CreationDate="2020-05-25T15:56:36.180" Score="5" Body="&lt;p&gt;The &quot;blobs&quot; referred to in the IFLS article are, more correctly, areas of strong magnetic flux at the Earth's surface. The term &quot;blob&quot; is not scientifically significant, it just refers to a region where the magnetic field coming from Earth's core is stronger than elsewhere. Often we'd depict the magnetic field with a contour map of field strength, giving peaks and troughs of strong and weak field the appearance of &quot;blobs&quot; or patches, like this summary image from &lt;a href=&quot;https://www.nature.com/articles/s41561-020-0570-9&quot; rel=&quot;nofollow noreferrer&quot;&gt;the publication in question&lt;/a&gt;:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JconW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JconW.jpg&quot; alt=&quot;Radial magnetic flux at Earth&amp;#39;s surface. Copyright P. Livermore, from ESA http://www.esa.int/Applications/Observing_the_Earth/Swarm/Magnetic_north_and_the_elongating_blob&quot;&gt;&lt;/a&gt;&#xA;(source: P. Livermore, via ESA: &lt;a href=&quot;http://www.esa.int/Applications/Observing_the_Earth/Swarm/Magnetic_north_and_the_elongating_blob&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.esa.int/Applications/Observing_the_Earth/Swarm/Magnetic_north_and_the_elongating_blob&lt;/a&gt;)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The maps show the radial magnetic field strength at Earth's surface in 1999, and then the field in 2019, this time with a trail showing the movement of the North magnetic dip pole (the star) since 1999. The two &quot;blobs&quot; of stronger field can be seen to change, the one over Siberia gets bigger and pulls the pole towards it, away from the now smaller Canadian one.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;These &quot;blobs&quot; of strong field on the maps aren't &quot;molten material in Earth's interior&quot;, but we can infer from maps like this what the field would look like at the surface of the outer core, and then from there what the movement of the material within the outer core might have been in order to generate the magnetic field we've observed. This is thanks to &lt;a href=&quot;https://en.wikipedia.org/wiki/Alfv%C3%A9n%27s_theorem&quot; rel=&quot;nofollow noreferrer&quot;&gt;(math heavy :( ) frozen-flux theorem&lt;/a&gt;, that essentially says magnetic field is &quot;frozen&quot; into the iron-rich fluid at the surface of the Earth's outer core, so acts like a tracer for the fluid movement at the top of the outer core.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;For an idea of what the flow (labelled &quot;|U|&quot;) of material at the surface of the core might look like during the last 20 years to produce the field (labelled &quot;Br&quot;, note the flipped color scheme), here are stills from the same model cited by the publication's authors of the field and flow at the core surface in 1999 and 2017. The Canadian &quot;blob&quot; gets stretched out and weaker relative to a strengthening Siberian &quot;blob&quot;, as the flow speeds up under Canada:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Cmul8m.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Cmul8m.gif&quot; alt=&quot;Magnetic field and flow at the core surface 1999&quot;&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/BkzHtm.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BkzHtm.gif&quot; alt=&quot;Magnetic field and flow at the core surface 2017&quot;&gt;&lt;/a&gt;&#xA;(Source: &lt;a href=&quot;https://geodyn.univ-grenoble-alpes.fr/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://geodyn.univ-grenoble-alpes.fr/&lt;/a&gt;, play with the great visualisations, but the animations are enormous files!)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So yes, you can map the distinct location of these &quot;blobs&quot; of strong field (though only &lt;em&gt;outside&lt;/em&gt; the core), but bear in mind the maps are plotted with largely irrelevant choices of contour levels -- the field is continuous and varies smoothly, it's been drawn like this to highlight the &quot;blobs&quot; more clearly.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Edit: added images of field and flow at the core surface to clarify, and make this answer a bit long...)&lt;/p&gt;&#xA;" OwnerUserId="14123" LastEditorUserId="14123" LastEditDate="2020-05-28T12:39:18.013" LastActivityDate="2020-05-28T12:39:18.013" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19770" PostTypeId="2" ParentId="16366" CreationDate="2020-05-26T14:57:31.723" Score="-1" Body="&lt;p&gt;In the Zambretti's documentation on Winter the Z number falling is lower by 1 unit, and the Summer Rising improves the prospect to 1 unit, therefore we have to adjust:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Winter Z=Z+1&#xA;Summer Z=Z-1&lt;/p&gt;&#xA;&#xA;&lt;p&gt;To compensate the derivation.&lt;/p&gt;&#xA;" OwnerUserId="20508" LastActivityDate="2020-05-26T14:57:31.723" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19771" PostTypeId="1" CreationDate="2020-05-26T21:46:37.627" Score="1" ViewCount="68" Body="&lt;p&gt;In the 1950s in England in an otherwise cloudless blue sky in summer a very small dense cloud appeared overhead around midday which looked like cumulus and for about 5 minutes we had torrential rain. The cloud dissipated and the rest of the day remained cloudless. A truly odd experience that I can’t explain.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What could have happened, what could have caused it?&lt;/p&gt;&#xA;" OwnerUserId="20511" LastEditorUserId="6016" LastEditDate="2020-05-27T15:17:26.163" LastActivityDate="2020-05-27T15:17:26.163" Title="Torrential rain from a tiny cloud in otherwise blue sky" Tags="|meteorology|" AnswerCount="0" CommentCount="7" ClosedDate="2020-05-27T15:17:16.590" ContentLicense="CC BY-SA 4.0" />
  <row Id="19772" PostTypeId="1" CreationDate="2020-05-28T03:17:47.660" Score="1" ViewCount="64" Body="&lt;p&gt;I took a photo of an amazing sight I had never seen outside my home ( southern india ) but I could not tell if it was a rainbow type thing or an aurora borealis. Also if it was to be a sun dog , shouldn’t it have some curvature and symmetry .Can someone tell what this is and it’s reason of occurrence &lt;a href=&quot;https://i.stack.imgur.com/9pFgG.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9pFgG.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20518" LastEditorUserId="6258" LastEditDate="2020-05-28T05:25:03.070" LastActivityDate="2020-05-28T10:25:10.570" Title="Rainbowish phenomenon outside my home" Tags="|meteorology|atmosphere|geophysics|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19773" PostTypeId="2" ParentId="15684" CreationDate="2020-05-28T04:21:55.003" Score="1" Body="&lt;p&gt;Dust would not have to be chemically poisonous to render air unbreathable but a big impact would first of all release a blast of hot plasma that nothing nearby will survive with accompanying air blast. Dust would be mostly from Earth material and that will vary in chemistry according to what is locally present; the &lt;a href=&quot;https://www.lpi.usra.edu/science/kring/Chicxulub/global-effects/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chicxulub&lt;/a&gt; (dinosaur killer) impact hit where abundant calcium sulphate minerals were present and those were thought to have caused acid rain (as well as releasing a lot of CO2 that, along with massive wildfires, caused later global warming). I suspect those kinds of dusts at high levels would be poisonous but the heat alone from material thrown into the air and lower space was thought to cause spontaneous wildfires over large areas around the planet - making the dust superfluous for rendering air unbreathable.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2020-05-28T04:21:55.003" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19775" PostTypeId="2" ParentId="19772" CreationDate="2020-05-28T10:25:10.570" Score="1" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Sun_dog&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sun dogs&lt;/a&gt; are bright spots to one or both sides of the sun. They are a form of halo created by ice crystals in the atmosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What you saw was most likely &lt;a href=&quot;https://en.wikipedia.org/wiki/Cloud_iridescence&quot; rel=&quot;nofollow noreferrer&quot;&gt;cloud iridescence&lt;/a&gt;, which is a phenomenon that occurs closed to either the moon of the sun. The iridescence is caused by diffraction created by water droplets or small ice crystals individually scattering light. Large crystals produce a halo, not iridescence. &lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-05-28T10:25:10.570" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19778" PostTypeId="2" ParentId="6723" CreationDate="2020-05-28T17:15:18.127" Score="-2" Body="&lt;p&gt;Nastapoca Arc is the result of a multi-pivot oblique delta impact dating back ca. 3.7 Ga. The other other related and simultaneous impacts are these:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Canda NW territories, crushing Nunavut into its current islands.&lt;/li&gt;&#xA;&lt;li&gt;Hudson bay south, the dent forming the southern most point.&lt;/li&gt;&#xA;&lt;li&gt;Gulf of Saint Lawrence.&lt;/li&gt;&#xA;&lt;li&gt;Greenland (its hollow centre) knocking it off from mainland Canada, rotating 90% clock wise.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;We know its impactor.&lt;/p&gt;&#xA;" OwnerUserId="20524" LastEditorUserId="6016" LastEditDate="2020-05-28T19:41:06.440" LastActivityDate="2020-05-28T19:41:06.440" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19780" PostTypeId="1" AcceptedAnswerId="19834" CreationDate="2020-05-29T11:20:51.763" Score="5" ViewCount="4907" Body="&lt;p&gt;I am curious how do mountain springs get their water. The water flowing from them eventually forms rivers.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is it only from rain and snow? Or does water also come from underground-below the mountain (if so, then how does it &quot;climb&quot; to the spring which is at a high altitude)?&lt;/p&gt;&#xA;" OwnerUserId="20527" LastActivityDate="2022-06-10T23:50:22.590" Title="How do mountain springs get their water?" Tags="|water|mountains|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19781" PostTypeId="1" CreationDate="2020-05-30T06:03:57.793" Score="1" ViewCount="90" Body="&lt;p&gt;It is true that there are multiple definitions of a continent. But it is also true that Europe fails to satisfy any of them. One of the boundaries between Europe and Asia was chose arbitrarily(the Ural mountains)by Peter The Great and before that, it was the Russian border(a line in the sand). It is not even a subcontinent like India and Arabia.The separation between Europe and Asia was a hypothesis of ancient Greek cartographers; who discovered that both Europe and Asia were part of a single landmass. So can we assume that this is just political on the part of Europeans who like feeling special?&lt;/p&gt;&#xA;" OwnerUserId="17742" LastActivityDate="2020-05-30T06:03:57.793" Title="Why is Europe still considered a continent(along with Asia)?" Tags="|plate-tectonics|geography|continent|" AnswerCount="0" CommentCount="3" ClosedDate="2020-05-31T00:42:56.687" ContentLicense="CC BY-SA 4.0" />
  <row Id="19782" PostTypeId="1" CreationDate="2020-05-30T07:04:19.013" Score="1" ViewCount="54" Body="&lt;p&gt;When looking at the earth wind map, some lines clearly distinguish themselve and act as &quot;frontier&quot; between stream of wind. I was wondering what it was and what was causing them? Thanks.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ursxH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ursxH.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20532" LastActivityDate="2020-05-30T07:04:19.013" Title="Why some area in the ocean seems to have like &quot;wind barrier&quot;?" Tags="|meteorology|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="19783" PostTypeId="1" AcceptedAnswerId="19784" CreationDate="2020-05-30T16:27:56.257" Score="1" ViewCount="103" Body="&lt;p&gt;I am comparing NO2 and PM2.5 levels in the pre-2020 Jan-April and 2020 Jan-April (representing air quality during lockdown and under no-lockdown conditions).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The data was from the aqicn website (&lt;a href=&quot;https://aqicn.org/data-platform/covid19/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://aqicn.org/data-platform/covid19/&lt;/a&gt;). The data is not raw concentrations, it is converted into the US EPA standard, which I &lt;strong&gt;believe&lt;/strong&gt; is represented as AQI values.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Can someone please explain why with PM2.5, the data reaches from 'Good' to 'Hazardous', whereas the NO2 is only within the 'Good' bracket. &#xA;I'm hoping it is because PM2.5 is more  harmful than NO2? &lt;/p&gt;&#xA;&#xA;&lt;p&gt;But if it is because I should be using a different scale for NO2 (e.g., 0-10 = Good, 10-20 = Moderate, etc.) I'd like to know - I haven't been able to find different AQI scales for different pollutants.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xRayd.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xRayd.jpg&quot; alt=&quot;PM2.5&quot;&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/e4pMq.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/e4pMq.jpg&quot; alt=&quot;NO2&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20535" LastActivityDate="2020-05-31T18:48:42.647" Title="How is Air Quality Index relevant to both PM2.5 and NO2" Tags="|air-quality|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19784" PostTypeId="2" ParentId="19783" CreationDate="2020-05-30T19:03:39.990" Score="2" Body="&lt;p&gt;Most locations in the US don't see high concentrations of pollutants like NO&lt;sub&gt;2&lt;/sub&gt; and CO anymore.  They are largely no longer an air quality problem and air is &quot;Good&quot; in regards to those pollutants.  Especially during &quot;lockdown&quot;, when traffic is light.  This is largely thanks to tailpipe emissions standards for vehicles and a much more fuel efficient fleet. On the other hand, PM2.5 has multiple sources that cause high concentrations, and we are much more likely to see the AQI vary beyond &quot;Good&quot; PM2.5 (e.g. outdoor fires, wood-stoves, secondary aerosol formation).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The AQI is based on health-based evidence, with a different concentration threshold for each pollutant.  These are all put onto the AQI scale for simple communication to the public. If concentrations of NO2 had reached levels of the NAAQS, then you would see your graph plot into those AQI levels (note NO&lt;sub&gt;2&lt;/sub&gt; doesn't go as far up in &quot;AQI&quot; values as PM2.5 on your graph because those NO&lt;sub&gt;2&lt;/sub&gt; concentrations were never detected by the monitor).  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The National Ambient Air Quality Standard (NAAQS) for nitrogen dioxide (NO&lt;sub&gt;2&lt;/sub&gt;) is a 1-hour NO&lt;sub&gt;2&lt;/sub&gt; standard of 100 parts per billion (ppb). See &lt;a href=&quot;https://www3.epa.gov/airnow/no2.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www3.epa.gov/airnow/no2.pdf&lt;/a&gt; and page 2 here: &lt;a href=&quot;http://njaqinow.net/App_Files/2016/AQI%202016.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://njaqinow.net/App_Files/2016/AQI%202016.pdf&lt;/a&gt; which has the break levels for each pollutant, shown below:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HP4Ez.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HP4Ez.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="2470" LastEditDate="2020-05-31T18:48:42.647" LastActivityDate="2020-05-31T18:48:42.647" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19785" PostTypeId="1" CreationDate="2020-05-30T20:37:27.140" Score="1" ViewCount="161" Body="&lt;p&gt;While studying about atmospheric waves, I found a passage in my book in which a equation involved the term  &lt;span class=&quot;math-container&quot;&gt;$$ \frac{1}{\alpha }\frac{\partial \alpha }{\partial z}$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt; is the specific volume of air , which was replaced by &lt;span class=&quot;math-container&quot;&gt;$$ \frac{1}{\theta }\frac{\partial \theta }{\partial z}$$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; is the potential temperature, but with no details on how this was done. I tried to find a relationship between specific volume and potential temperature that would give me this equivalence, but with no success. How can I prove this?&lt;/p&gt;&#xA;" OwnerUserId="20538" LastActivityDate="2020-05-31T01:12:45.117" Title="What is the relationship between the derivatives of specific volume and potential temperature with height?" Tags="|meteorology|thermodynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19786" PostTypeId="2" ParentId="19785" CreationDate="2020-05-31T01:12:45.117" Score="3" Body="&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\theta=T\left(\frac{P_0}{P}\right)^\frac{R_d}{c_p} \tag{1}$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\alpha=R_d T P^{-1} \tag{2}$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial P}{\partial z}=-\rho g \tag{3}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/19517/derivative-of-exner-function/19519#19519&quot;&gt;It can be shown that &lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial \theta}{\partial z}=\frac{\theta}{T}(\frac{\partial T}{\partial z}+\frac{g}{c_p }) \tag{4}$$&lt;/span&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Therefore &lt;span class=&quot;math-container&quot;&gt;$$\frac{1}{\theta}\frac{\partial \theta}{\partial z}=\frac{1}{T}(\frac{\partial T}{\partial z}+\frac{g}{c_p })\tag{5}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So if we take &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial \alpha}{\partial z}$&lt;/span&gt;, we find &lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial \alpha}{\partial z}=R_dP^{-1}\frac{\partial T}{\partial z}-R_dTP^{-2}\frac{\partial P}{\partial z}\tag{6}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Then we can rewrite (6) using (2):&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial \alpha}{\partial z}=\frac{\alpha}{T}\frac{\partial T}{\partial z}-\alpha P^{-1}\frac{\partial P}{\partial z}\tag{7}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Divide by &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$$\frac{1}{\alpha}\frac{\partial \alpha}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}- P^{-1}\frac{\partial P}{\partial z}\tag{8}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Employing (3) &lt;span class=&quot;math-container&quot;&gt;$$\frac{1}{\alpha}\frac{\partial \alpha}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}+ P^{-1}\rho g\tag{9}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Which is the equivalent of &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Employing (3) &lt;span class=&quot;math-container&quot;&gt;$$\frac{1}{\alpha}\frac{\partial \alpha}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}+ P^{-1}\alpha^{-1} g\tag{10}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, it may get a little sketchy in this derivation. But we're close. Assuming an adiabatic transformation (&lt;span class=&quot;math-container&quot;&gt;$dH=c_p dT-Pd\alpha=0$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$H-H_0=c_pT-P\alpha$&lt;/span&gt;), we can rewrite (10) to look a little funky&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{1}{\alpha}\frac{\partial \alpha}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}+ \frac{g}{H-H_0-P\alpha}\tag{11}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since enthalpy is conserved, &lt;span class=&quot;math-container&quot;&gt;$H=H_0$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{1}{\alpha}\frac{\partial \alpha}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}+ \frac{g}{c_p T}\tag{12}$$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;And finally,&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\therefore \frac{1}{\alpha}\frac{\partial \alpha}{\partial z}=\frac{1}{T}\left(\frac{\partial \alpha}{\partial z}=\frac{1}{T}\frac{\partial T}{\partial z}+ \frac{g}{c_p}\right)=\frac{1}{\theta}\frac{\partial \theta}{\partial z}$$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-05-31T01:12:45.117" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19787" PostTypeId="1" CreationDate="2020-05-31T15:11:48.717" Score="3" ViewCount="485" Body="&lt;p&gt;Today I saw a rainbow after almost a decade. I live in Noida (a city) in India. Most people I know believe that: &lt;strong&gt;we don't see rainbows nowadays because of pollution&lt;/strong&gt; and now after nearly 3 months since the COVID lock-down, the pollution must have come down and the rainbow was visible. Is this the reason why rainbows have become so rare or is it a false belief?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Here is news about the rainbow I saw &lt;a href=&quot;https://inshorts.com/m/en/amp_news/double-rainbow-spotted-in-delhincr-parts-of-haryana-after-rainfall-pics-surface-1590932520797&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;(so you can see the photos)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;According to this site &lt;a href=&quot;https://aqicn.org/map/delhi/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://aqicn.org/map/delhi/&lt;/a&gt; PM2.5 in Delhi(very close to Noida) today is &lt;span class=&quot;math-container&quot;&gt;$74$&lt;/span&gt; and last year in 2019 on this day was &lt;span class=&quot;math-container&quot;&gt;$151$&lt;/span&gt;. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the answer is yes, how does pollution impact rainbows? &lt;/p&gt;&#xA;" OwnerUserId="20544" LastEditorUserId="20544" LastEditDate="2020-05-31T20:10:48.210" LastActivityDate="2020-05-31T20:10:48.210" Title="Is pollution the reason why rainbows are so rare nowadays?" Tags="|meteorology|air-pollution|rain|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19788" PostTypeId="1" CreationDate="2020-05-31T16:58:21.080" Score="3" ViewCount="34" Body="&lt;p&gt;I have been taught that the changes in current were caused primarily by climate change but upon reading the conclusion of the paper named: &quot;Observed decline of the Atlantic meridional overturning circulation 2004–2012&quot; I am left baffled if climate change caused the change in the currents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Citation for the paper : Smeed, D. A., McCarthy, G. D., Cunningham, S. A., Frajka-Williams, E., Rayner, D., Johns, W. E., Meinen, C. S., Baringer, M. O., Moat, B. I., Duchez, A., and Bryden, H. L.: Observed decline of the Atlantic meridional overturning circulation 2004–2012, Ocean Sci., 10, 29–38, &lt;a href=&quot;https://doi.org/10.5194/os-10-29-2014&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.5194/os-10-29-2014&lt;/a&gt;, 2014.&lt;/p&gt;&#xA;" OwnerUserId="20545" LastEditorUserId="6467" LastEditDate="2020-05-31T18:21:05.393" LastActivityDate="2020-05-31T18:21:05.393" Title="Is the slowing down of the Atlantic meridional overturning circulation a response to climate change?" Tags="|oceanography|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19789" PostTypeId="1" AcceptedAnswerId="19791" CreationDate="2020-06-01T02:51:56.427" Score="1" ViewCount="606" Body="&lt;p&gt;Magnesium represents 0.07 % of the composition of the Sun's photosphere while aluminum represents 0.006 %. Therefore, there is much more magnesium than aluminum in the Sun's photosphere.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;But the same does not happen in the Earth's crust, where magnesium represents 2.9 % of its composition and aluminum represents 8.1 %.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is there a particular reason why this is so?&lt;/p&gt;&#xA;" OwnerUserId="18551" LastEditorUserId="18551" LastEditDate="2020-06-04T05:56:02.050" LastActivityDate="2023-12-23T03:49:09.993" Title="Why does the Earth's crust have more aluminum than magnesium while the Sun has more magnesium than aluminum?" Tags="|planetary-science|crust|planetary-formation|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19790" PostTypeId="1" CreationDate="2020-06-01T10:44:58.853" Score="8" ViewCount="195" Body="&lt;p&gt;I've always thought that the process of planetary accretion was energetic enough to keep the proto-Earth entirely molten, and the subsequent evolution of the planet (the formation of the crust, etc...) was simply centered on its cooling by gradual liberation of the trapped heat (from those planetesimal collisions and radioactive decay).&lt;/p&gt;&#xA;&lt;p&gt;But recently I've read that there was a particular event called core-mantle differentiation, or the &amp;quot;Iron Catastrophe&amp;quot;, that occurred after the formation of Earth (and before he formation of the Moon), which transformed &lt;a href=&quot;http://astro.hopkinsschools.org/course_documents/earth_moon/earth/geologic_time/iron_catastrophe.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;&amp;quot;an undifferentiated mass of solid rock&amp;quot;&lt;/a&gt; into a magma ocean.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Does this means that previous to the core-mantle differentiation, the Earth had a primitive solid surface? That this surface was turned into a magma ocean because of the feedback loop of core-mantle differentiation and then, when things cooled down, a second generation crust formed (which was later destroyed by Theia's giant impact)?&lt;/li&gt;&#xA;&lt;li&gt;Does the process of rapid accretion of planetary embryos trapped so little heat inside Earth that the additional heat from radioactive decay was needed to build up enough temperature to melt the iron afterwards? Does this mean that each of the planetesimal impacts melted only part of the embryo (I guess that if they could yield enough energy to melt the entire object they would have made possible Earth's differentiation way before the core-mantle differentiation)? Does these impacts were infrequent enough that the embryo could have solidified and cooled down before the next accreting event? How can accretion form an undifferentiated Earth before the core-mantle differentiation at all?&lt;/li&gt;&#xA;&lt;li&gt;If a planet is accreted only from non-radioactive material, should we expect an Earth-size planet with no differentiated interior? Since radioactive decay was apparently needed for the &amp;quot;Iron Catastrophe&amp;quot;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="18279" LastEditorUserId="6298" LastEditDate="2021-08-16T08:07:56.943" LastActivityDate="2021-08-16T08:07:56.943" Title="Wasn't Earth a magma ocean before core-mantle differentiation?" Tags="|planetary-science|geothermal-heat|planetary-formation|iron|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="19791" PostTypeId="2" ParentId="19789" CreationDate="2020-06-01T11:20:29.430" Score="4" Body="&lt;p&gt;On the earth as a whole, there is much more magnesium than aluminium.&lt;/p&gt;&#xA;&lt;p&gt;Your question is why, specifically in the crust, there is more aluminium than magnesium.&lt;/p&gt;&#xA;&lt;p&gt;The reason is that Mg is a &lt;em&gt;compatible&lt;/em&gt; element whereas Al is an &lt;em&gt;incompatible&lt;/em&gt; element. There were several questions here that addressed some aspects of this topic, for example:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/2950/725&quot;&gt;What are the high field strength and large ion lithophile (HFS or HFSE &amp;amp; LIL or LILE) elements?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/6893/725&quot;&gt;What was the likely composition of Earth&amp;#39;s early crust (how did crustal composition evolve)?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/7760/725&quot;&gt;Why silicon is abundant in earth surface?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/174/725&quot;&gt;Why do felsic materials have lower melting points than mafic?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;h1&gt;Why is there more Al than Mg in the crust?&lt;/h1&gt;&#xA;&lt;p&gt;In earth's (upper) mantle, most Mg is inside the mineral olivine, with some in other minerals such as clinopyroxene and orthopyroxene. In contrast, most Al is in the minerals plagioclase, spinel, and garnet. There could be a tiny amount of Al in the pyroxenes as well.&lt;/p&gt;&#xA;&lt;p&gt;When you melt the solid mantle rock that is composed of all of the minerals I listed above, some minerals melt at lower temperatures than the others. So the magma composition that is formed more closely resembles those minerals that melted.&lt;/p&gt;&#xA;&lt;p&gt;As you can guess, the Mg-rich minerals are &lt;em&gt;refractory&lt;/em&gt; (that is, they are harder to melt). The Al-rich minerals are usually very easy to melt. So whenever you have magma that comes from the mantle into the crust, it will have more Al than Mg. Over the billions of years of Earth's crustal evolution, quite a lot of Al (along with Na, K, Fe, Ca, and Si) accumulated in the crust, relative to the amount that was in the parental mantle.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-06-02T00:26:38.230" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19792" PostTypeId="1" CreationDate="2020-06-01T21:35:15.530" Score="1" ViewCount="158" Body="&lt;p&gt;This is a follow-up to my question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/19570/if-its-ice-sheet-were-removed-under-modern-atmospheric-conditions-what-climatic&quot;&gt;If its ice sheet were removed under modern atmospheric conditions, what climatic and ice-sheet equilibrium would be re-established over Antarctica?&lt;/a&gt;. As it has received no answers so far, I have decided to attempt to figure out an answer by simulating the scenario myself.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Specifically, the simulations would have these atmospheric and orbital starting conditions:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Last Glacial Maximum&lt;/li&gt;&#xA;&lt;li&gt;1913 (The absolute last year of the Little Ice Age if I were to pick one, due to the disappearance of glaciers from the Spanish Sierra Nevada)&lt;/li&gt;&#xA;&lt;li&gt;Current (2020)&lt;/li&gt;&#xA;&lt;li&gt;RCP-2.6&lt;/li&gt;&#xA;&lt;li&gt;RCP-8.5&lt;/li&gt;&#xA;&lt;li&gt;Fuck it, let's just burn &lt;em&gt;all&lt;/em&gt; the fossil fuels&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Given the very low albedo of the rock and open ocean, (in the latter 5 scenarios) the matching of the Southern Hemisphere summer with perihelion, the adiabatic lapse rate, and the greater incursion of warm lower-latitude air masses all working together to warm its climate, I have wondered since 2012 what equilibrium would be reached with ice cover on Antarctica given subsequent feedbacks, and how this would affect the climate of the rest of the world. Again, though I don't presume it will be very important with regards to the actual process of setting up the simulation, note that I don't just mean melted away, I mean removed from the Earth's surface (and preferably with any glacial accumulation, re-added to maintain a constant sea level). Where it ends up and how it ends up there is not important.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have BEDMAP 2 (the most authoritative Antarctic subglacial topographic map set) in addition to ETOPO1 and BedMachine 3 (Greenlandic equivalents—I plan on also doing this for Greenland), and have heard of some reasonable public climate models (the low-res GUI-based EdGCM and the more-advanced CSCM, for example), but don't know how to proceed from there.&lt;/p&gt;&#xA;" OwnerUserId="17317" LastActivityDate="2020-08-18T22:06:45.747" Title="How would I simulate the effects of the Antarctic ice sheet being deleted on Earth's climate?" Tags="|climate-change|climate|climate-models|glaciology|hypothetical|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="19793" PostTypeId="1" CreationDate="2020-06-02T05:27:08.897" Score="4" ViewCount="215" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nuWkO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nuWkO.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The plot above is about the concentration of siderophile elements in the terrestrial mantle.&#xA;From the logarithmic plot, we can deduce that the concentration of highly siderophile elements is quite uniform.&#xA;Why ?&lt;/p&gt;&#xA;" OwnerUserId="18200" LastEditorUserId="18081" LastEditDate="2020-06-17T15:49:57.920" LastActivityDate="2020-06-17T15:49:57.920" Title="Why is the concentration of highly siderophile elements so uniform in the mantle?" Tags="|geochemistry|mantle|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19794" PostTypeId="2" ParentId="19793" CreationDate="2020-06-02T13:26:42.367" Score="6" Body="&lt;p&gt;First, note that this plot is normalized to a reference, here the composition of CI chondrites (your version lacks the Y axis label, it's figure 2.1 from &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6376203/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Walker 2016&lt;/a&gt;). So if the concentration of highly siderophile elements (HSE) seems uniform, it's partly because it is a &lt;em&gt;relative&lt;/em&gt; concentration, not an absolute one. If you look at the raw data (Table 1.1), you'll see that the absolute concentrations vary by more than one order of magnitude depending on the element (from 0.35 ppb for Re to 7.6 for Pt). Also, as you noted the scale is logarithmic, which tends to flatten the differences.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now, why do HSE have the same relative abundance in the mantle compared to chondrites? Because elements from the same family show the same behavior—actually it's why they form a family in the first place. HSE all are, well, &lt;em&gt;highly siderophile&lt;/em&gt;, so they all went into the core during the core segregation, and now they all are highly depleted in the mantle compared to chondrites.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that despite this depletion, HSE are actually still too abundant in the mantle: there should be even less of them. Geochemists have long debated this issue. This nice paper (&lt;a href=&quot;https://doi.org/10.1016/j.chemer.2008.10.001&quot; rel=&quot;nofollow noreferrer&quot;&gt;Walker 2009&lt;/a&gt;) reviews the different hypotheses that might explain this HSE &quot;enrichment&quot;: incomplete core segregation, lower metal/silicate partitioning, late accretion of chondritic material after core segregation...&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2020-06-17T15:43:53.987" LastActivityDate="2020-06-17T15:43:53.987" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19797" PostTypeId="1" AcceptedAnswerId="19800" CreationDate="2020-06-03T19:54:45.520" Score="2" ViewCount="59" Body="&lt;p&gt;I'm interested in knowing what features can still be discerned.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've been struggling find any image of a thin section of a rock under a regular light microscope, or a petrographic microscope with the polarizer and analyzer removed.&lt;/p&gt;&#xA;" OwnerUserId="20556" LastEditorUserId="725" LastEditDate="2020-06-04T09:14:25.977" LastActivityDate="2020-06-04T09:14:25.977" Title="What would a rock thin section look like without any polarizers?" Tags="|geology|petrography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19798" PostTypeId="1" CreationDate="2020-06-03T23:56:20.547" Score="1" ViewCount="426" Body="&lt;p&gt;Only in later years have I understood anything about how our planet moves around itself and around the Sun, and how it therefore appears to always &quot;rise in the East&quot; and &quot;set in the West&quot;, apparently &quot;traveling across the sky&quot; (but it's actually our planet that is traveling and spinning at the same time while the Sun is fixed in the centre). At least I'm &lt;em&gt;pretty&lt;/em&gt; sure that there are no exceptions to this rule, but I wouldn't be surprised if things are different in other positions on Earth's surface.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Anyway, Japan is called the &quot;land of the rising sun&quot;, supposedly because it is... far to the... East? But the Earth is spherical, so this has no meaning, does it? Yes, North is &quot;up&quot;, but East... there is nowhere you can say that East &quot;ends&quot; because the most extreme East position on a 2D world map is just next to where the &quot;West&quot; is beginning. So is the idea that just because (some?) world maps have Japan to the right, and thus &quot;East&quot; in some misleading sense, then Japan is the &quot;land of the rising sun&quot;?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This confuses me. Does the sunrise and sunset have something particular about it when you are watching it from Japan, as opposed to central Europe or North America or anywhere else? Is this just a reference to semi-recent &quot;Western&quot; world maps? I'm pretty sure that Asian world maps place themselves in the centre rather than in the &quot;far East&quot;?&lt;/p&gt;&#xA;" OwnerUserId="20557" LastActivityDate="2020-06-04T00:18:47.440" Title="What exactly does it mean that Japan is the &quot;land of the rising sun&quot;?" Tags="|sun|" AnswerCount="1" CommentCount="1" ClosedDate="2020-06-05T00:28:02.040" ContentLicense="CC BY-SA 4.0" />
  <row Id="19799" PostTypeId="2" ParentId="19798" CreationDate="2020-06-04T00:18:47.440" Score="3" Body="&lt;p&gt;Nippon means &quot;sun origin&quot; or &quot;land of the rising sun&quot;. From the direction and point of view of the older, larger civilisation of the continent to the West - China - the island of Japan were in the general direction of where the sun rises, with no known lands further East beyond them.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;China was a powerful cultural influence for Japan. Nihon/Nippon was a nicer, more poetic name than the Chinese name of &quot;Wa&quot; - which was Chinese for &quot;Dwarf&quot;; Nihon/Nippon (&quot;sun origin&quot;) was used, possibly intentionally, to supplant it within Japan. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I don't know if Japanese or Chinese historically understood that Earth was a globe but suspect it was largely irrelevant to that naming.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2020-06-04T00:18:47.440" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19800" PostTypeId="2" ParentId="19797" CreationDate="2020-06-04T09:14:17.633" Score="3" Body="&lt;p&gt;It would look almost identical to the image obtained using plane-polarised light.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Some minerals would look darker, especially those with strong pleochroism such as biotites and amphiboles, because all light is now transmitted or blocked regardless of orientation.&#xA;Minerals with large relief differences such as carbonates (e.g. calcite) would cease to have the differences and would just have high relief.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;From a static image it could actually be hard to tell that there is no polariser. A careful and experienced observer might deduce it from small hints, given some prior knowledge on what the rock contains.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-06-04T09:14:17.633" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19801" PostTypeId="1" CreationDate="2020-06-05T09:41:19.333" Score="3" ViewCount="164" Body="&lt;p&gt;The local derivative is linked to the total derivative by:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\frac{\partial T}{\partial t} = \frac{DT}{Dt} - \mathbf{U} \cdot \nabla T$&lt;/span&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;and the -&lt;span class=&quot;math-container&quot;&gt;$ \mathbf{U} \cdot \nabla T$&lt;/span&gt; term represent the change by advection.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, for example cold air blowing in a region of warm temperatures will bring cold advection and it will contribute negatively to the local derivative.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have trouble interpreting the &lt;span class=&quot;math-container&quot;&gt;$\frac{DT}{Dt}$&lt;/span&gt; term. If it represents how the temperature is changing withing the flow regardless of the flow moving to cooler/warmer regions, what could this be caused by ? Say expansion and consequent cooling of the air parcels ?&lt;/p&gt;&#xA;" OwnerUserId="20566" LastActivityDate="2020-07-10T15:50:04.507" Title="Total differentiation" Tags="|meteorology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19802" PostTypeId="2" ParentId="19801" CreationDate="2020-06-05T15:04:10.137" Score="2" Body="&lt;p&gt;As far as the question &quot;What can be causing this?,&quot; there are a variety of reasons. Let's look at the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/First_law_of_thermodynamics&quot; rel=&quot;nofollow noreferrer&quot;&gt;First law of Thermodynamics&lt;/a&gt; (including molecular diffusion): &lt;span class=&quot;math-container&quot;&gt;$$\frac{DU}{Dt}=c_p\frac{DT}{Dt}=Q-p\frac{D\alpha}{Dt}+\nu \nabla^2 U$$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$U$&lt;/span&gt; is the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Internal_energy&quot; rel=&quot;nofollow noreferrer&quot;&gt;internal energy&lt;/a&gt; of the ideal gas, &lt;span class=&quot;math-container&quot;&gt;$Q$&lt;/span&gt; is diabatic heating, &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; is pressure, and &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt; is the specific volume, &lt;span class=&quot;math-container&quot;&gt;$\nu$&lt;/span&gt; is the molecular diffusivity, and &lt;span class=&quot;math-container&quot;&gt;$c_p$&lt;/span&gt; is the isobaric specific heat capacity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So, without diabatic heating, one way is to change the volume or pressure, which varies the most with changes in altitude (you can rewrite the &lt;span class=&quot;math-container&quot;&gt;$-p\frac{D\alpha}{Dt}$&lt;/span&gt; term as &lt;span class=&quot;math-container&quot;&gt;$\alpha \frac{Dp}{Dt}\approx \alpha \frac{\partial p}{\partial z}\approx\alpha\rho g=g=-\Gamma_d c_p$&lt;/span&gt;, &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Dry-adiabatic_lapse_rate&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;span class=&quot;math-container&quot;&gt;$\Gamma_d$&lt;/span&gt; is the dry adiabatic lapse rate&lt;/a&gt;). Using that relationship, (1) may be rewritten as &lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial T}{\partial t}=\frac{Q}{c_p}+\nu\nabla^2T-\frac{g}{c_p}-\Gamma_d- \vec{u} \cdot\nabla T$$&lt;/span&gt; Another way is through molecular heat exchange, which is so small it is usually neglected, unless it is in a micrometeorological context. And then there is diabatic heating, perhaps the most loaded term of the equation.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Diabatic heating is any heating source that requires entropy to change. This includes latent heat exchange, radiative heating, etc. Turbulent mixing may arguably be considered in this for large scales, but not small scales. &lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-06-05T15:04:10.137" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19805" PostTypeId="2" ParentId="11973" CreationDate="2020-06-06T18:08:06.323" Score="1" Body="&lt;p&gt;Sorry to be un-arty but you should be able to measure scattered light intensity at the coast versus inland. My guess is that it is brighter at the coast which also probably also means it gets lighter in the morning and light lasts longer into the evening.&#xA;Land in the place I live is covered in green and is quite absorbent of light, i.e. dark. It's pretty, but the sea is usually lighter than er.. a forest or farmland. In the desert this may well be different.&#xA;So my guess is that the light is special at the seaside or more special on a peninsula because there is more of it - more light and more light time at dawn and dusk. How prosaic.&#xA;The light should still be measured. An explanation is good only if it fits the facts. &lt;/p&gt;&#xA;" OwnerUserId="20571" LastActivityDate="2020-06-06T18:08:06.323" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19808" PostTypeId="1" CreationDate="2020-06-07T17:32:21.297" Score="1" ViewCount="37" Body="&lt;p&gt;I have my views and you have yours, so I ask a question, what was the average sea level in Athens, Greece 2,720 years ago? What was the average sea level in ancient Rome 2,420 years ago? &lt;a href=&quot;https://en.wikipedia.org/wiki/History_of_theatre&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/History_of_theatre&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Ancient towns have been found that were built thousands of years ago when the towns were above sea level. My bet is the average sea level was at its lowers 2,720 years ago when most of the planet was covered in ice. The sea will continue to rise until the ice caps melt.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Will New York be under water then? When the caps/glaciers melt, what will the average world sea level be considering the volume of the known ice caps/glacier smelt?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;At the rising rate of the seas, when will New York, Miami, and other coastal lined cities be underwater---- Anyone care to calculate the year when NY will be completely submerged?&#xA;&lt;a href=&quot;https://www.nationalgeographic.com/news/2010/3/100304-snowball-earth-ice-global-warming/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nationalgeographic.com/news/2010/3/100304-snowball-earth-ice-global-warming/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20575" LastEditorUserId="2470" LastEditDate="2020-06-07T18:50:00.843" LastActivityDate="2020-06-07T18:50:00.843" Title="What will the sea level be when the ice caps/glaciers melt?" Tags="|oceanography|sea-level|" AnswerCount="0" CommentCount="8" ClosedDate="2020-06-08T13:40:29.213" ContentLicense="CC BY-SA 4.0" />
  <row Id="19809" PostTypeId="1" CreationDate="2020-06-07T18:00:43.637" Score="1" ViewCount="48" Body="&lt;p&gt;I'm having a water well drilled on my property. The drilling crew has been working since Wednesday. They are using an airlift rig with a 6in bore. They are at 300ft and only have 4gpm. I would really like to determine what formation this well is in before I make a decision Monday on whether they should continue drilling. I really need to get ~15gpm from this well, but 30+ would be ideal. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;The well is in the fall line hills area of Alabama. Specifically, it is here: 32.9672430, -86.8522270. That roughly corresponds to &lt;a href=&quot;https://i.stack.imgur.com/Sp0ID.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;this location on the physiographic map of Alabama.&lt;/a&gt; The bore went through a few feet of topsoil, then about 30ft of brown/white/yellow clay then 60ft of grey/black clay. At 90ft he hit consolidated rock, a grey/black shale that produces &lt;a href=&quot;https://i.imgur.com/w3m9IZ3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;rock fragments&lt;/a&gt; and a &lt;a href=&quot;https://i.stack.imgur.com/wak4W.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;clay-like substance when pulverized.&lt;/a&gt; The well is cased to 100ft. At 260ft we hit water and the well was producing 4gpm. At 300ft the rate remained unchanged. The well driller has told me that the material alternates between hard and soft layers and that he has hit a few pockets of limestone. The shale fragments are scratched by steel, copper, and aluminum. There is no distinct odor from the shale. There are sparse fragments of quartz. I haven't seen any pyrite. The shale does not burn, even under a propane torch. The location has an outcropping of what I believe is &lt;a href=&quot;https://i.stack.imgur.com/cV03S.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;sandstone with a good bit of quartz.&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Since the bedding is shale, I think this well is in the Valley and Ridge formations. I think it is in the Coosa River valley formation, although the land drains into the Cahaba. The well driller has told me that the rock is Chattanooga Shale, but I'm not sure that is correct because it doesn't have any smell, doesn't seem to contain any pyrite, doesn't combust, and would have to be 200ft thick. From what I understand the Chattanooga Shale formation isn't that thick.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If this well is in Chattanooga Shale I may be out of luck because it's an aquiclude. That is unless I could drill through it and get into another formation within 450ft or so.&lt;/p&gt;&#xA;" OwnerUserId="20574" LastActivityDate="2020-06-07T18:00:43.637" Title="What local formation am I drilling?" Tags="|geology|structural-geology|hydrogeology|regional-geology|geologic-layers|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19810" PostTypeId="1" CreationDate="2020-06-07T19:57:02.610" Score="2" ViewCount="88" Body="&lt;p&gt;Does that mean that the Earth gained the classification of a planet that long ago rather than some other celestial body? How did they determine that this happened that long ago? How discrete is the period of non planet to planet?&lt;/p&gt;&#xA;" OwnerUserId="20576" LastActivityDate="2020-06-07T19:57:02.610" Title="What do scientists mean when they say the Earth formed 4.56 billion years ago?" Tags="|geology|earth-history|" AnswerCount="0" CommentCount="3" ClosedDate="2020-06-20T19:35:03.517" ContentLicense="CC BY-SA 4.0" />
  <row Id="19811" PostTypeId="1" CreationDate="2020-06-07T21:09:07.007" Score="5" ViewCount="311" Body="&lt;p&gt;I find Ꞓ such an odd-looking symbol. What's the historical significance, etc, of that symbol? &lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Latin letter C with bar&#xA;  &lt;a href=&quot;https://i.stack.imgur.com/7FCgD.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7FCgD.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;My understanding is, C was the Carboniferous, K for Cretaceous... why not just use a different letter?&lt;/p&gt;&#xA;" OwnerUserId="20578" LastEditorUserId="6535" LastEditDate="2020-06-10T03:28:30.283" LastActivityDate="2020-06-10T03:28:30.283" Title="Why is Cambrian denoted with such a weird symbol?" Tags="|geology|time|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19814" PostTypeId="1" CreationDate="2020-06-09T08:35:45.250" Score="1" ViewCount="80" Body="&lt;p&gt;Costs related to space exploration are well documented. &#xA;However, what about the costs of Earth projects like dam/mines/tunnels? &#xA;What has been the most expensive projects? I know that nuclear power plants construction costs may reach the 10 billions of dollars/eur, but what about other projects?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;As an example, how much did cost to set up the Ghawar oil field in Saudi Arabia?&#xA; How expensive was the South Deep gold mine in South Africa?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;My question is triggered by the expected costs related to deep geological disposal of radioactive waste, it should be on the order of 50/100 billions USD/EUR, so I would like to compare apples and oranges to understand how credible is that estimate.&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2020-06-09T08:35:45.250" Title="What is the most expensive project related to Earth's geology and/or to engineering geology on the Earth?" Tags="|geology|economic-geology|world-building|energy|" AnswerCount="0" CommentCount="11" ClosedDate="2020-06-09T13:18:57.847" ContentLicense="CC BY-SA 4.0" />
  <row Id="19815" PostTypeId="1" CreationDate="2020-06-09T09:30:37.973" Score="1" ViewCount="43" Body="&lt;p&gt;Since I use OTHER as a pollutant ID, are there some parameters I could specify in order to get better results for dispersion of substance I am trying to model? eg. molecular weight or density?&lt;/p&gt;&#xA;" OwnerUserId="20583" LastActivityDate="2021-03-21T08:47:40.660" Title="How can I specifiy a substance in AERMOD?" Tags="|models|air-pollution|pollution|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19816" PostTypeId="1" CreationDate="2020-06-09T19:38:17.300" Score="4" ViewCount="127" Body="&lt;p&gt;Why does the pressure increase only by 0,3-0,4bar per km in stone but 1bar per 10m in water while stone has the higher density?&lt;/p&gt;&#xA;" OwnerUserId="20587" LastActivityDate="2020-06-11T11:12:14.843" Title="Pressure Increase in stone and in water" Tags="|geology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19817" PostTypeId="1" CreationDate="2020-06-10T04:28:32.163" Score="1" ViewCount="47" Body="&lt;p&gt;&lt;a href=&quot;https://phys.org/news/2020-06-marine-microfibres-plastic.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Marine microfibres: less plastic than predicted&lt;/a&gt; (Phys.org)&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Microfibers are fine strands of thread used to make clothing, carpeting and household items like mops. They are found in the air we breathe, the water we drink, and throughout the world's oceans. Natural, rather than synthetic, microfibers, though, make up the majority of those found in the ocean's surface waters—despite the fact that currently two-thirds of all human-produced fibers are synthetic.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;This is based on the paper: &lt;a href=&quot;https://advances.sciencemag.org/content/6/23/eaay8493&quot; rel=&quot;nofollow noreferrer&quot;&gt;Microfibers in oceanic surface waters: A global characterization&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;They seem to assume that all the &quot;natural&quot; fibres (wool, cotton) are &quot;anthropogenic&quot; (e.g. clothing, carpeting).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Do they consider the possibility that some of the &quot;natural&quot; fibres may come from plants or animals without human intervention?&lt;/strong&gt; E.g., animals shedding hair or plant fibres washed into rivers.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2020-06-10T08:15:38.413" Title="Marine microfibres: less plastic than predicted" Tags="|human-influence|pollution|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19818" PostTypeId="1" CreationDate="2020-06-10T05:48:36.277" Score="1" ViewCount="92" Body="&lt;p&gt;One part of my garden has a heavy, dark clay soil. It is now waterlogged with a lot of surface water that does not shift at all even after a day of waiting. When pressed into a 4mm thick ribbon, it breaks under its own weight after about 10 or 15cm. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I do not have a photo to hand, but may try to upload later.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I took a large handful of the material and compressed into a ball. I rolled it around until smooth and left it on my outside windowsill to dry. When I came back to it late the next day, it was completely solid, like a little cannon ball. It is not quite as heavy as an iron ball, but it has that same dark faded metallic grey iron colour, though much less metallic, more like slightly reflective but matt. Knocking it on the wall, it doesn't flake, chip or crack. It's solid as a stone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Is this normal for clay? I was under the impression it needed to be fired to become solid like that. The reason I ask is I have a partly demolished wall that I would like to restore, and I am thinking that perhaps I could just excavate this area of the garden to use as a building material, rather than try to solve my drainage problem. If this is not normal for clay, how could I identify what it might be, and if/how to use it as a building material? If I can make a cob from this, would that be suitable for an outdoor wall?&lt;/p&gt;&#xA;" OwnerUserId="20590" LastEditorUserId="20590" LastEditDate="2020-06-10T05:55:50.027" LastActivityDate="2020-06-10T05:55:50.027" Title="Is it normal for clay soil to solidify into a very hard, but not brittle, material in air, and if not what might this soil be?" Tags="|soil|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="19819" PostTypeId="2" ParentId="19817" CreationDate="2020-06-10T07:58:44.563" Score="1" Body="&lt;p&gt;They don't mention it explicitly. But they don't classify further than &quot;natural&quot; and &quot;synthetic&quot;. And, may I say, animal husbandry as well as agricultural use of the producers of such natural fibres (e.g. jute, wool) are under human control as well. They are introduced into the ocean via waste-water, rivers, wash from the continents.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The study used samples from surface waters, if I understand it correctly from reading superficially. They say that too many fibres are prematurely seen as &quot;microplastic&quot; while they may actually be natural. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Other studies have come to the conclusion that the missing plastic-fibre in surface waters rests &lt;a href=&quot;https://science.sciencemag.org/content/368/6495/1140&quot; rel=&quot;nofollow noreferrer&quot;&gt;deeper&lt;/a&gt; in the water column, or may come in small(er) &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0269749120310253#!&quot; rel=&quot;nofollow noreferrer&quot;&gt;sizes&lt;/a&gt; than sampled.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-06-10T08:15:38.413" LastActivityDate="2020-06-10T08:15:38.413" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19820" PostTypeId="1" CreationDate="2020-06-10T14:07:21.083" Score="1" ViewCount="208" Body="&lt;p&gt;I have read the various answers to this question provided by people with a higher intellect than me, however I am still confused. Even from the ISS your view is to the horizon some 1,435 miles in all directions. Is the view not the same as being on a very small island in the middle of the sea on earth but just covering a larger area?&lt;/p&gt;&#xA;" OwnerUserId="20593" LastActivityDate="2020-06-10T14:07:21.083" Title="How high must one be to see the curvatue of the earth with the naked eye?" Tags="|earth-observation|" AnswerCount="0" CommentCount="3" ClosedDate="2020-06-10T14:52:28.020" ContentLicense="CC BY-SA 4.0" />
  <row Id="19821" PostTypeId="1" CreationDate="2020-06-11T04:54:54.920" Score="2" ViewCount="107" Body="&lt;p&gt;I found a very cool video here:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Draining Earth's oceans, revealing the two-thirds of Earth's surface we don't get to see&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=-uOwv_Krqk8&amp;amp;feature=emb_logo&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=-uOwv_Krqk8&amp;amp;feature=emb_logo&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, I am looking for a video that demonstrates the sea-level goes up. I think there'd be many of them because it's a result of the Global warming. But I can't find any. Can someone post one?&lt;/p&gt;&#xA;" OwnerUserId="20595" LastActivityDate="2020-06-12T00:02:15.187" Title="Is there any animation to demonstrate if the sea level rise up?" Tags="|climate-change|sea-level|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19822" PostTypeId="2" ParentId="19816" CreationDate="2020-06-11T11:12:14.843" Score="3" Body="&lt;blockquote&gt;&#xA;  &lt;p&gt;Why does the pressure increase only by 0,3-0,4bar per km in stone but 1bar per 10m in water while stone has the higher density?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;h2&gt;Because it doesn't!&lt;/h2&gt;&#xA;&#xA;&lt;p&gt;Plots in &lt;a href=&quot;https://physics.stackexchange.com/a/184039/83380&quot;&gt;this Physics SE answer&lt;/a&gt; and &lt;a href=&quot;https://www.researchgate.net/figure/The-pressure-at-different-depths-in-the-Earths-interior_fig12_228377528&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;https://www.researchgate.net/figure/The-pressure-inside-the-Earth-as-a-function-of-depth-The-data-are-taken-from-the_fig2_320302392&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; show about 0.4 or 0.5 &lt;span class=&quot;math-container&quot;&gt;$\times 10^6$&lt;/span&gt; bar at 1000 km depth, which is 0.4 or 0.5 bar &lt;em&gt;per meter&lt;/em&gt; compared to your 0.1 bar per meter for water. If rock is 4 to 5 times denser than water, then all is well.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2020-06-11T11:12:14.843" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19823" PostTypeId="1" CreationDate="2020-06-11T23:52:31.177" Score="1" ViewCount="51" Body="&lt;p&gt;When Earth formed &lt;span class=&quot;math-container&quot;&gt;$\approx 4.5 \times 10^9$&lt;/span&gt; years ago, Earth's surface rocks emitted more radiation because they had more unstable isotopes. All short half-life isotopes decayed long ago, and the amount of long half-life isotopes has decreased. How much radiation did rocks emit &lt;span class=&quot;math-container&quot;&gt;$\approx 4.5 \times 10^9$&lt;/span&gt; years ago?&lt;/p&gt;&#xA;" OwnerUserId="20598" LastEditorUserId="6467" LastEditDate="2020-06-12T23:00:42.503" LastActivityDate="2020-06-12T23:00:42.503" Title="When Earth formed 4.5 × 10⁹ years ago, how much radiation did surface rocks emit?" Tags="|rocks|radioactivity|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19824" PostTypeId="2" ParentId="19821" CreationDate="2020-06-12T00:02:15.187" Score="1" Body="&lt;p&gt;There is this NASA animation showing 12-13 years between 2002 and 2015. It is interesting for showing the counter-intuitive lowering of sea levels nearest to land based ice mass losses, especially around Greenland and Pacific Alaska. This is due to local gravitational effects, ie less ice mass reduces the pull on ocean water near where the ice melts, so water levels actually fall in such places, whilst places furthest from them experience the greatest sea level rise.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;(Any tips for embedding this video?)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://youtu.be/VY_SeZiBcM4&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://youtu.be/VY_SeZiBcM4&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2020-06-12T00:02:15.187" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19826" PostTypeId="1" CreationDate="2020-06-12T11:23:19.850" Score="2" ViewCount="122" Body="&lt;p&gt;I have recently stumbled across &lt;a href=&quot;https://youtu.be/_v9ssqsSwrE?t=30&quot; rel=&quot;nofollow noreferrer&quot;&gt;this video on Youtube&lt;/a&gt;, where quite a magnificient building is carved into the soil with simple tools like a shovel and hoe. The location is somewhere in South America, according to the channel description.&lt;/p&gt;&#xA;&lt;p&gt;The rock seems to be (easily) workable, but also stable enough to maintain smooth surfaces and carved shapes.&lt;/p&gt;&#xA;&lt;p&gt;See this picture for reference:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/V4qsr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/V4qsr.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;What kind of soil/rock is this?&lt;/p&gt;&#xA;&lt;p&gt;Edit: There is no need to watch the whole video. The reference image pretty much sums up what is going on, and what's the basis of my question respectively, at least in my opinion.&lt;/p&gt;&#xA;&lt;p&gt;Edit 2: As &lt;em&gt;John&lt;/em&gt; pointed out in the comments, at one point the soil is mixed with water to make a clay plaster.&lt;/p&gt;&#xA;" OwnerUserId="20601" LastEditorUserId="20601" LastEditDate="2020-06-21T09:34:09.657" LastActivityDate="2020-06-21T09:34:09.657" Title="What kind of soil is being worked in this video?" Tags="|geology|sedimentology|soil|" AnswerCount="0" CommentCount="15" ClosedDate="2020-06-16T06:21:28.460" ContentLicense="CC BY-SA 4.0" />
  <row Id="19827" PostTypeId="1" CreationDate="2020-06-11T19:55:44.367" Score="1" ViewCount="30" Body="&lt;p&gt;Specifically I'm looking for climate data (average temperature, precipitation) for the summer months of 2018 in Belgium and of 2019 in Japan. Ideally of high spatial resolution, because my areas of study are limited to a transect of a few kilometers in each country.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've come across other sites such as WorldClim and Prism, but they are always historical data not covering the time intervals I'm looking for, and/or limited to the USA.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I'm trying to examine a possible link between litter decomposition rate and climate at these sites. The decomposition experiment was only conducted over a a timespan of approximately 3 months. Hence I would prefer the climate data of these exact time intervals, and not historical averages or the data collected by nearby weather stations which may record quite different temperatures if they are located in an urban setting. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;However, if I need to choose between historical averages that are spatially accurate versus climate data of the exact interval but not spatially accurate (from the nearest weather station), what should I choose for a meaningful comparison between my two sample locations in Belgium and Japan?&lt;/p&gt;&#xA;" OwnerDisplayName="Bantha" LastActivityDate="2020-06-13T10:10:37.367" Title="Database of monthly climate data 2018 - 2019" Tags="|ecology|database|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19828" PostTypeId="1" CreationDate="2020-06-14T11:54:53.273" Score="1" ViewCount="223" Body="&lt;p&gt;In &lt;a href=&quot;https://www.asa3.org/ASA/resources/Wiens.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Radiometric Dating: A Christian Perspective&lt;/a&gt;, the author argues (persuasively, I think) in favor of the mainstream interpretation of radiometric dating (as opposed to the claims of young earth creationists). He says the fact that short-lives isotopes are generally not found on Earth is evidence showing that the Earth is billions of years old.&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;Just about the only radioisotopes found naturally are those with very long half-lives of close to a billion years or longer.... The only isotopes present with shorter half-lives are those that have a source constantly replenishing them...&lt;/p&gt;&#xA;  &#xA;  &lt;p&gt;The Earth is old enough that radioactive isotopes with half-lives less than half a billion years decayed away, but not so old that radioactive isotopes with longer half-lives are gone.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I would guess that some of these shorter-lived elements still exist in minute amounts because a decay curve has a long tail, but &lt;strong&gt;is the basic statement correct - that shorter-lived, non-replenished radioactive isotopes are absent (or nearly so) from Earth?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Where can I read more about this?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;&lt;strong&gt;Clarification&lt;/strong&gt;: I didn't make it clear enough, but I'm specifically asking about the relative abundance of &lt;strong&gt;non-replenished&lt;/strong&gt; radioisotopes - those that are not produced on Earth by natural processes. Eg, excluding carbon-14 (produced in the atmosphere by cosmic rays), excluding thorium-230 (produced by the decay of uranium-234), etc.&lt;/p&gt;&#xA;" OwnerUserId="18728" LastEditorUserId="18728" LastEditDate="2020-06-15T02:09:07.757" LastActivityDate="2020-06-20T17:13:42.350" Title="Does the relative abundance of radioactive isotopes reflect their half-lives?" Tags="|radioactivity|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="19830" PostTypeId="2" ParentId="19828" CreationDate="2020-06-14T18:14:01.250" Score="1" Body="&lt;p&gt;While a long half-life, hundreds or millions of years or more, favors a radioisotope being relatively common or even occurring in nature at all, it is not the only consideration.  Whether and how effectively the isotope can be regenerated also figures in.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.m.wikipedia.org/wiki/Isotopes_of_niobium&quot; rel=&quot;nofollow noreferrer&quot;&gt;Niobium&lt;/a&gt;.   occurs as only one isotope, &lt;span class=&quot;math-container&quot;&gt;$_{41}^{93}\text{Nb}$&lt;/span&gt;.  All other isotopes decay away much too quickly, including &lt;span class=&quot;math-container&quot;&gt;$_{41}^{94}\text{Nb}$&lt;/span&gt; with a half-life of only about 20,300 years -- not enough to survive in the billions of years since primordial times when the Earth formed.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Now look at carbon.  The radioisotope carbon-14, &lt;span class=&quot;math-container&quot;&gt;$_{6}^{14}\text{C}$&lt;/span&gt;, has a half-life of only 5730 years so surely it, too, is all gone, meeting the same end as &lt;span class=&quot;math-container&quot;&gt;$_{41}^{94}\text{Nb}$&lt;/span&gt;.  In fact, as many readers know, carbon-14 is still with us (even if it's only trace amounts) and in use as a probe for dating organic matter.  The difference, of course, is there is a readily available mechanism for regenerating this isotope through &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Cosmogenic_nuclide&quot; rel=&quot;nofollow noreferrer&quot;&gt;the action of cosmic rays high above Earth&lt;/a&gt;.  The availability of this mechanism means carbon-14 need not have enough half-life to survive billions of years since the Earth's formation, only enough to survive weeks of circulation time to get to the ground.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;We can correlate half-life to abundance only when comparing isotopes that are &lt;strong&gt;formed by similar mechanisms.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2020-06-14T18:21:02.233" LastActivityDate="2020-06-14T18:21:02.233" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19831" PostTypeId="1" CreationDate="2020-06-14T21:50:52.087" Score="2" ViewCount="134" Body="&lt;p&gt;I've not come up against clear explanations when trying to think about a situation where an ice sheet is advancing and comes up against a cliff. &lt;strong&gt;What happens next? How does the ice sheet cross the cliff? Does the base get stuck?&lt;/strong&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Does it create some landforms into the original cliff-face? The forcing that would apply should be very strong (and perhaps it will continue to apply over a very long time period). Also, how does the flow of the glacier happen in these locations? Will the cliff-face be exposed to liquid water flow throughout the period that the ice sheet has covered it, and won't this cause very rapid erosion of the cliff-surface?&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;From a geologic perspective, this would have been happening across the &lt;a href=&quot;https://en.wikipedia.org/wiki/Baltic_Klint&quot; rel=&quot;nofollow noreferrer&quot;&gt;Baltic Clint&lt;/a&gt; though most of these cliffs are in the range of 15–25 meters—in other words, relatively small for an ice sheet to cross. However, there are also some exposed (presently above-water) parts which are slightly higher.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I've put a small map (20m DEM; generally one front of cliffs by the modern coastline and then occasional ones further inland) below which illustrates where this would have been happening during the last glaciation period based on the example of Tallinn, Estonia, though by no means is this the only place where such a situation would have occurred. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YIEBM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YIEBM.jpg&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Of course, the DEM has further problems, including that ~20k years of isostatic uplift has raised these a fair bit since so the actual obstacle that the ice sheets met should have been smaller (perhaps was: are the remnant limestone mounds the part that didn't get washed away?).&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I also find the sentence (from the above Wikipedia page) weird:&lt;/p&gt;&#xA;&#xA;&lt;blockquote&gt;&#xA;  &lt;p&gt;However it is not known to which degree the Baltic Klint originated in postglacial time or if it evolved from cliff-like forms sculpted by the Fennoscandian Ice Sheet. In Gotland 20th century cliff retreat rates have been estimated at 0.15 to 0.78 cm/year.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&#xA;&lt;p&gt;I don't see how the ice sheet's advance/retreat could have caused such a cliff if the limestone plateau did not exist there beforehand.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;I'm not expecting an answer based on this location specifically, but rather perhaps there are some imaged cliff-faces in Greenland/Antarctica where this behaviour has been recorded presently? I tried some searches and found &lt;a href=&quot;https://ui.adsabs.harvard.edu/abs/2017AGUFM.C33D1226P/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; which seems relevant but I wasn't able to access the full text.&lt;/p&gt;&#xA;" OwnerUserId="8425" LastEditorUserId="8425" LastEditDate="2020-06-16T10:55:24.740" LastActivityDate="2020-06-17T15:53:44.110" Title="What behaviour does an ice sheet exhibit in crossing a cliff?" Tags="|glaciology|" AnswerCount="1" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="19833" PostTypeId="1" AcceptedAnswerId="19835" CreationDate="2020-06-15T21:35:19.830" Score="5" ViewCount="295" Body="&lt;p&gt;I am seeking information on how weather models use randomness (if at all). From what I can gather daily weather forecasting uses partial differential equations with initial and boundary conditions plugged in from data. Do they use randomness to vary the initial conditions (to account for uncertainty)? Or is there some point in the modeling process where randomness is inserted (e.g. drawing from a normal distribution)? Or are weather models completely deterministic?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I read a thread on EarthScienceSE for probability of precipitation (PoP), and it still isn't clear to me if there is any randomness at all in the model and how its output is averaged over a given area. How are the &quot;confidence in any precipitation&quot; and &quot;coverage area&quot; generated (which are multiplied to get the overall PoP)?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I know that &quot;chance of rain&quot; is a very specific example, but I am interested more generally where randomness is used in common weather models. E.g. &quot;this model uses the normal distribution to estimate this quantity&quot; etc. Specific information is especially appreciated, e.g. name of model and where it uses random numbers. Any help is appreciated!&lt;/p&gt;&#xA;" OwnerUserId="20613" LastActivityDate="2020-06-16T10:00:21.953" Title="How/where is randomness/stochasticity used in weather prediction" Tags="|meteorology|models|weather-forecasting|" AnswerCount="1" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19834" PostTypeId="2" ParentId="19780" CreationDate="2020-06-15T21:51:08.320" Score="2" Body="&lt;p&gt;Ultimately, it comes from precipitation.  Ordinarily we think of rain as coming from low-level clouds, but Putkonen[&lt;a href=&quot;https://doi.org/10.1657/15230430(2004)036[0244:CSARDA]2.0.CO;2&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;] has compiled rainfall data in the Himalayas showing significant rains up to several thousand meters altitude, covering the range where practically everyone lives.  It is this precipitation that fills the underground tables mentioned by Jean-Marie Prival in a comment to the question.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Such a source is subject to the effects of climate change, which accordingly has led to significant environmental issues.  See Ref [&lt;a href=&quot;https://doi.org/10.1659/MRD-JOURNAL-D-11-00079.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;].&lt;/p&gt;&#xA;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;1.&#xA;Jaakko K. Putkonen, &quot;Continuous Snow and Rain Data at 500 to 4400 m Altitude near Annapurna, Nepal, 1999–2001&quot;, &lt;em&gt;Arctic, Antarctic, and Alpine Research&lt;/em&gt;, 36:2, 244-248 (2004)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;2.&#xA;Sandeep Tambe, Ghanashyam Kharel, ML Arrawatia, Himanshu Kulkarni, Kaustubh Mahamuni, Anil K Ganeriwala,&#xA;&quot;Reviving dying springs: climate change adaptation experiments from the Sikkim Himalaya&quot;,&#xA;&lt;em&gt;Mountain Research and Development&lt;/em&gt; 32 (1), 62-72 (2012)&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2020-06-15T21:51:08.320" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19835" PostTypeId="2" ParentId="19833" CreationDate="2020-06-15T23:04:48.663" Score="7" Body="&lt;p&gt;Probability is used in weather forecasting. I will only highlight some examples due to my lack of knowledge in some areas.&lt;/p&gt;&#xA;&lt;p&gt;Before initializing a forecast model the data needs to be assimilated. That means we need to somehow put measurements from ground based stations, satellites etc. into the model and fit this data to the grid. We then have an &amp;quot;atmospheric state estimate&amp;quot;. This usually involves the minimization of cost functions. Typically the uncertainty of this &amp;quot;atmospheric state estimate&amp;quot; is used in the process of &lt;strong&gt;ensemble forecasting&lt;/strong&gt;. An introduction to data assimilation can be found &lt;a href=&quot;https://www.ecmwf.int/assets/elearning/da/da1/story_html5.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here at ECMWF&lt;/a&gt;. Every operational weather forecasting model has to do this data assimilation process. Since you specifically asked for names, here are a few: Global Forecasting System (GFS, probably the model you weather app uses), ECMWF model (European Center for Medium Range Weather Forecasts), Icosaheadral Nonhydrostatic Model (ICON, operational model of german weather service),High Resolution Local Area Modelling for numerical weather prediction (HIRLAM, operational model of some Scandinavian countries).&lt;/p&gt;&#xA;&lt;p&gt;In an ensemble forecast the equations are solved as you stated in the question. However, there are certain aspects of the model that are varied to account for uncertainties. These aspects can include the initial conditions (including time, sometimes time-lag is used), variations of parameterizations (and there are a lot of them, basically for every process that can not be resolved by the model grid) and sometimes even multi-model ensembles. The model is then initiated many times to obtain multiple and different forecasts. Again, there is a nice introduction &lt;a href=&quot;https://www.ecmwf.int/en/about/media-centre/fact-sheet-ensemble-weather-forecasting&quot; rel=&quot;nofollow noreferrer&quot;&gt;at ECMWF&lt;/a&gt;. Some ideas on how to visualize ensemble forecasts can be found &lt;a href=&quot;https://www.in.tum.de/fileadmin/w00bws/cg/Research/Publications/2016/TimeHierarchicalClustering/timeclus_preprint.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;All of the above focussed on probability in the course of initializing a model. However, even if no ensemble is used and if we'd know the state of the atmosphere without error - we'd still have to rely on probability due to sub grid scale processes. A prominent example is cloud cover. Suppose we have a mean humidity &lt;span class=&quot;math-container&quot;&gt;$q$&lt;/span&gt; in a grid cell (which is what the model gives us). Clouds will only form if &lt;span class=&quot;math-container&quot;&gt;$q &amp;gt; q_s$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$q_s$&lt;/span&gt; is the saturation humidity. Depending on other parameters like temperature a probability density function &lt;span class=&quot;math-container&quot;&gt;$Q(T,...)$&lt;/span&gt; is assumed. A possible parameterization for cloud cover could be that the fraction of &lt;span class=&quot;math-container&quot;&gt;$Q(T,...)$&lt;/span&gt; larger than &lt;span class=&quot;math-container&quot;&gt;$q_s$&lt;/span&gt; defines cloud cover. I will not give examples for typical distributions used, since this is an active area of research. Once more I'd like to refer to &lt;a href=&quot;https://www.ecmwf.int/sites/default/files/elibrary/2005/16958-parametrization-cloud-cover.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;ECMWF&lt;/a&gt; if you wish to see some details and examples of pdf's used.&lt;/p&gt;&#xA;&lt;p&gt;Finally, I'd like to add that a main source of uncertainty in models (there is not necessarily probability used) is the parameterization of of convection (shallow and deep). Precipitation is highly related to humidity and convection and therefore large errors are often the result of parameterization.&lt;/p&gt;&#xA;&lt;p&gt;I hope this helps somewhat.&lt;/p&gt;&#xA;&lt;p&gt;Edit: Regarding the precipitation problem. What you see at google or the typical weather app is based on model simulations but most certainly not a model output. If google tells you &amp;quot;30% rain probability at your place&amp;quot; then this will most likely refer to a 30% chance that precipitation in an (by google unspecified) area exceeds a certain threshold. The certainty is&#xA;is generated by looking at the ensemble. The threshold is exceeded in 30% of the simulations. This is also the reason why a high resolution model is less accurate. It is easier to predict that it's raining 0.1 l somewhere in New York tomorrow than to predict that it rains 0.1 l in the central park tomorrow.&lt;/p&gt;&#xA;" OwnerUserId="18833" LastEditorUserId="-1" LastEditDate="2020-06-18T08:25:19.090" LastActivityDate="2020-06-16T10:00:21.953" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19837" PostTypeId="1" CreationDate="2020-06-16T14:42:24.753" Score="3" ViewCount="160" Body="&lt;p&gt;Apologies if this is a poorly written question, I'm writing this on my phone.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;I noticed that there were a lot of rather long rivers in the region in question, and I began to wonder just how connected they are. I came up with the following path:&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Start in Mobile, Alabama, and head north along the Tombigbee River past the Mississippi-Alabama border and into Mississippi. It seems to go through some name changes, but near the Tennessee-Alabama-Mississippi border, it connects with the Tennessee River. Follow the Tennessee River north through Kentucky and Kentucky Lake, where it will eventually meet the Ohio River. That, in turn, feeds into the Mississippi River, which flows back to the Gulf of Mexico.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It seems to me that it makes the region enclosed an island, since it is impossible to reach it without crossing a body of water. But is this significant in any other way? I can tell that not all the rivers flow in the same direction, and it's possible that some portions of the water around it were artificially created, is there anything else that comes as a result of this?&lt;/p&gt;&#xA;" OwnerUserId="20618" LastActivityDate="2020-06-17T07:02:41.547" Title="Is Mississippi and parts of Alabama, Tennessee, and Kentucky one giant island?" Tags="|geography|islands|" AnswerCount="2" CommentCount="9" ClosedDate="2020-06-17T12:17:32.900" ContentLicense="CC BY-SA 4.0" />
  <row Id="19838" PostTypeId="2" ParentId="19837" CreationDate="2020-06-16T17:16:09.300" Score="2" Body="&lt;p&gt;It is possible to travel up the Tombigbee River to the Tennessee River. This is because parts of the Tombigbee River are man made.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Tennessee%E2%80%93Tombigbee_Waterway#Locks_and_dams&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Tennessee%E2%80%93Tombigbee_Waterway#Locks_and_dams&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The key part seems to be the &quot;Divide Cut,&quot; a canal linking the Tennessee and Tombigbee Rivers.&lt;/p&gt;&#xA;" OwnerUserId="11269" LastActivityDate="2020-06-16T17:16:09.300" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19839" PostTypeId="2" ParentId="19837" CreationDate="2020-06-17T05:18:13.127" Score="5" Body="&lt;p&gt;Rhetorical questions:&lt;/p&gt;&#xA;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Does the Erie Canal, which connects the Hudson River with Lake Erie make northern New York, southern Quebec, all of New England, all of New Brunswick, and the non-island parts of Nova Scotia an island?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Does the Chicago Sanitary and Ship Canal make all of the eastern part of the US an island?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Does Russia's Unified Deep Water System make Finland, Scandinavia, and Estonia an island, and mainland Europe another island?&lt;/p&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&#xA;&lt;p&gt;Humankind has learned to connect waterways with canals, locks, and dams. The sudden appearance of those canals, locks, and dams does not suddenly make those now disconnected lands into islands. The connection between the Tombigbee and the Tennessee rivers involves manmade canyons, manmade canals, and several manmade locks and dams.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;What about naturally narrow waterway connections? As an extreme example, consider the Committee's Punch Bowl in Alberta, Canada. This little lake has two little outlets. One of the outlets eventually joins the MacKenzie River, which flows into the Arctic Ocean. The other eventually joins the Columbia River, which flows into the Pacific Ocean.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;This leads to one last rhetorical question: Does the natural existence of the Committee's Punch Bowl make most of Washington state, most of British Columbia, almost all of the Yukon, and all of mainland Alaska into a very large &quot;island&quot;? Most geographers would say no.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="18081" LastEditDate="2020-06-17T07:02:41.547" LastActivityDate="2020-06-17T07:02:41.547" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19840" PostTypeId="2" ParentId="19453" CreationDate="2020-06-17T13:02:07.640" Score="0" Body="&lt;p&gt;Just to give some complementary informations from the other answer: the base of the Fortunian is indeed defined in eastern Canada on the basis of a &lt;strong&gt;trace&lt;/strong&gt; fossil (which obviously cannot be itself dated since it is just an imprint), &lt;em&gt;Trichophycus pedum&lt;/em&gt;. This trace fossil however being spread worldwide help correlating various sections throughout the world. One of such section is the  Birba-5 well in Oman where the radiometric age was actually measured (at least the one currently considered as the proper age of the base of the Cambrian): volcanic ash bed BB5 could be dated using &lt;span class=&quot;math-container&quot;&gt;$\ce{^{206}Pb/^{238}U}$&lt;/span&gt; radiometric dating at 541 +/- 0.63Ma, based on the analysis of 8 different zircon grains.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;It also corresponds to a negative carbon isotope excursion.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;See the Cambrian chapter and the Appendix 2 on radiometric ages in &lt;a href=&quot;https://www.sciencedirect.com/book/9780444594259/the-geologic-time-scale&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gradstein et al. 2012&lt;/a&gt;. Or &lt;a href=&quot;http://nora.nerc.ac.uk/id/eprint/3262/1/Bowring_et_al_AJS_2007.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bowring et al. 2007&lt;/a&gt; for the original data.&lt;/p&gt;&#xA;" OwnerUserId="87" LastActivityDate="2020-06-17T13:02:07.640" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19841" PostTypeId="2" ParentId="19831" CreationDate="2020-06-17T15:53:44.110" Score="1" Body="&lt;p&gt;This depends on a few things.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the cliff is small but widespread or the glacier is a huge, the glacier flows uphill until the cliff is gone. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;If the cliff is large the glacier flows around it, is diverted by it, or piles up behind it depending on the land around it.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Glaciers are pushed along by back pressure, like toothpaste out of a tube. As long as there is enough accumulation the toe of a glacier can be driven uphill, but like anything else glaciers take the path of least resistance so if it can be diverted by the cliff it will. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Note that the forces on the cliff will be huge, and exactly the forces rock is weak against, so the cliff is over topped it will be stripped away very quickly. &lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/16Tye.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/16Tye.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aFGIG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aFGIG.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2020-06-17T15:53:44.110" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19843" PostTypeId="1" CreationDate="2020-06-17T22:30:59.427" Score="1" ViewCount="151" Body="&lt;p&gt;My question relates to the fact that 1- the human population is continually increasing, and 2- everybody is constantly 'doing more stuff' (or causing more to be done). So doesn't 'more people doing more stuff' heat the environment correspondingly more and contribute directly to 'global heating'? Yet I have never heard of this argument, only that of increased greenhouse gas emissions blocking the dissipation of solar heat. I leave out the fact that, as people age, at some point they do a lot less stuff. (However, could they still cause overall even more stuff to be done, e.g. when they get sick and need intensive infrastructure -- care, transport, medicines, operations etc.)&lt;/p&gt;&#xA;&#xA;&lt;p&gt;There seems to be the general perception, or claim, that everything is 'getting more efficient', so we are thereby using less energy (and heat production, in my above model?). But some comentators say that this just leads us to use a lot more of the new, more efficient technology, so that overall energy consumption and heating increases. Could telephone use today per capita (and over some unit of time) actually consume &lt;em&gt;less&lt;/em&gt; energy than it did in, say, 1960? Offhand, it seems unlikely, especially since the definition of 'telephoning' today is much broader than the 1960s' activity.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could increasing direct heating of the earth by human activity perhaps not explain why, at present, we are seeing consistently higher global warming measurements than were only recently predicted? (Today's Guardian headline: 'Climate crisis: alarm at record-breaking heatwave in Siberia -- Unusually high temperatures in region linked to wildfires, oil spill and moth swarms'.) (Just consider how much 'new heat' is caused indirectly and directly by one more rocket launch. And of course there isn't 'just one more', but many more.) To be sure, a lot of this heat dissipates with time into space by natural processes. But isn't the global warming argument that the sun's heating of the earth is being accumulated in the greenhouse effect, so why shouldn't the 'direct' heat from human activity, released into the environment, also be captured and add to the overall effect? (Apologies to the experts here who may find my proposal much too simplistic, but I would be interested to hear why.)&lt;/p&gt;&#xA;" OwnerDisplayName="user20616" LastActivityDate="2020-06-18T02:14:57.710" Title="Doesn't increased human activity add to heating the atmosphere directly?" Tags="|climate-change|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19844" PostTypeId="2" ParentId="19843" CreationDate="2020-06-18T02:14:57.710" Score="3" Body="&lt;p&gt;It does, but globally it's negligible compared to other heat flux densities.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Simply do the math:&lt;/p&gt;&#xA;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;World wide primary energy consumption: 162,494 TWh (2018)&lt;/li&gt;&#xA;&lt;li&gt;Hours/year (2018): 8760 h&lt;/li&gt;&#xA;&lt;li&gt;Earth surface: 510,100,000,000,000 m²&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&#xA;&lt;p&gt;Assuming all this energy is transformed to atmospheric heating, this is an average heat flux (&lt;sub&gt;q&lt;/sub&gt;=E/&lt;sub&gt;t*A&lt;/sub&gt;) of 0.036 W/m². Locally this varies widely depending on climate (and the necessity to heat or cool buidlings), the degree of industrialisation, the population density etc. One figure I've found in Wikipedia for Germany: 1.2 W/m², Antarctica obviously: more or less 0.0 W/m², Hongkong (2018) 40.2 W/m² (calculated myself). BTW the average geothermal heat flux is 0.087 W/m².&lt;/p&gt;&#xA;&#xA;&lt;p&gt;Compare this to the solar contant: 1361 W/m². Considering albedo, day &amp;amp; night etc. the average (solar short wave) flux density on Earth's surface is ~ 175 W/m². The atmospheric back radiation is ~ 300 W/m².&lt;/p&gt;&#xA;&#xA;&lt;p&gt;So the average solar short wave flux density on Earth's surface alone is ~ 4,850 larger than the heat flux density &lt;strong&gt;directly&lt;/strong&gt; induced by human energy consumption.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The heat flux density &lt;strong&gt;indirectly&lt;/strong&gt; induced by human energy consumption (CO₂-, CH₄-, N₂O- etc. accumulation in the atmosphere) currently adds up to netto ~ 2.3 W/m² additional back radiation, which is roughly 60 times larger than the directly induced heat flux density.&lt;/p&gt;&#xA;&#xA;&lt;hr&gt;&#xA;&#xA;&lt;p&gt;Conclusion: direct heating of the atmosphere caused by energy consumption is almost insignificant compared to other effects.&lt;/p&gt;&#xA;" OwnerUserId="5282" LastActivityDate="2020-06-18T02:14:57.710" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19845" PostTypeId="1" AcceptedAnswerId="19867" CreationDate="2020-06-18T04:43:59.253" Score="2" ViewCount="395" Body="&lt;p&gt;I'm trying to reproject GRIB data from NOAA forecasts onto other data using Python and the pygrib and proj packages (among many others). What is the proper Proj string for GFS GRIBs?&lt;/p&gt;&#xA;&#xA;&lt;p&gt;The projection should come from the GRIB file and I assumed GFS uses Mercator, but pygrib &lt;code&gt;grib.projparams()&lt;/code&gt; returns&#xA;&lt;code&gt;{'a': 6371229, 'b': 6371229, 'proj': 'cyl'}&lt;/code&gt;. 'cyl' is not a legal proj CRS and other cylindrical projections (Central Cylindrical, Plate Carree) don't have a or b parameters. I assume that a &amp;amp; b are defining the earth as a sphere with radius 6371229m.&lt;/p&gt;&#xA;&#xA;&lt;p&gt;&lt;code&gt;grib.projparams()&lt;/code&gt; with an HRRR GRIB returns&#xA;&lt;code&gt;{'a': 6371229, 'b': 6371229, 'proj': 'lcc', 'lon_0': 262.5, 'lat_0': 38.5, 'lat_1': 38.5, 'lat_2': 38.5}&lt;/code&gt;&lt;/p&gt;&#xA;&#xA;&lt;p&gt;which is perfectly legal in the eyes of Proj and reprojects data accurately.&lt;/p&gt;&#xA;" OwnerUserId="20621" LastEditorUserId="20621" LastEditDate="2020-06-18T04:52:20.100" LastActivityDate="2020-06-26T07:55:10.267" Title="What CRS does GFS use?" Tags="|meteorology|python|gfs|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19848" PostTypeId="1" CreationDate="2020-06-19T06:12:47.040" Score="2" ViewCount="98" Body="&lt;p&gt;We need more batteries, to store renewable. But why don't they just pull down big balloons in the ocean and let them go up when they need the power?&lt;/p&gt;&#xA;" OwnerDisplayName="user20626" LastEditorUserId="6467" LastEditDate="2020-06-19T12:43:22.200" LastActivityDate="2020-06-19T12:43:22.200" Title="Why don't they use balloons in ocean as battery?" Tags="|climate-change|geoengineering|" AnswerCount="0" CommentCount="12" ClosedDate="2020-06-19T11:20:55.643" ContentLicense="CC BY-SA 4.0" />
  <row Id="19849" PostTypeId="1" CreationDate="2020-06-19T10:01:53.420" Score="5" ViewCount="266" Body="&lt;p&gt;I am aware that it's a bit general a question, and petroleum geology (or petrology ;-)) has never been a field of interest to me. A superficial search using related keywords brings up only economic figures about percentages here and there.&lt;/p&gt;&#xA;&lt;p&gt;From a geoscience point-of-view is there any chance to give an estimate, however rough it may be, of how much was ever produced in the biospehere (and abiogenic if that plays a role and can be set in number), and how much of that made it into reservoirs ?&lt;/p&gt;&#xA;&lt;p&gt;I am very well aware that there is &lt;em&gt;a lot&lt;/em&gt; of uncertainty, concerning formation processes, mobility in the crust, amount of current storage, past conditions favourable for the formation, etc, but maybe petroleum geology has once thought about it, and knows a rough number.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorUserId="2470" LastEditorDisplayName="user20217" LastEditDate="2021-04-23T05:30:09.227" LastActivityDate="2024-01-08T11:04:20.490" Title="How much of the petroleum ever formed has made it into reservoir rocks?" Tags="|earth-history|carbon-cycle|carbon|petroleum|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19851" PostTypeId="2" ParentId="19849" CreationDate="2020-06-19T22:15:23.107" Score="0" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;In its 1995 assessment of total world oil supplies, the U.S. Geological Survey (USGS) estimated that about 3 trillion barrels of recoverable oil originally existed on Earth and that about 710 billion barrels of that amount had been consumed by 1995.&lt;br /&gt;&#xA;&lt;a href=&quot;https://www.britannica.com/science/petroleum/Status-of-the-world-oil-supply&quot; rel=&quot;nofollow noreferrer&quot;&gt;Britannica&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;There may be much larger quantities that are not &amp;quot;recoverable&amp;quot;, depending on technology and economics.&lt;/p&gt;&#xA;&lt;p&gt;Also, for example, &lt;a href=&quot;https://gulfresearchinitiative.org/study-describes-oil-slick-differences-natural-seeps-deepwater-horizon/&quot; rel=&quot;nofollow noreferrer&quot;&gt;914 persistent natural seeps across the Gulf of Mexico collectively discharged about 500,000 barrels of oil per year&lt;/a&gt;. If that has been seeping for millions of years, that is a lot of oil that is not in reservoirs.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2020-06-19T22:15:23.107" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19852" PostTypeId="2" ParentId="10625" CreationDate="2020-06-20T15:35:25.250" Score="1" Body="&lt;p&gt;My guess is that it may be related to the currents, yes.&#xA;I suppose that the change in color, is due to a slightly different viscosity of the waters at the lanes, which may affect the reflecting light.&#xA;I think that if you could catch up swimming inside the lane, you would feel colder water.&lt;/p&gt;&#xA;" OwnerUserId="20632" LastActivityDate="2020-06-20T15:35:25.250" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19853" PostTypeId="2" ParentId="19828" CreationDate="2020-06-20T17:13:42.350" Score="2" Body="&lt;p&gt;Yes, the general idea you have is correct: isotopes with relatively short half-lives are found in quantities so minute as to be marginally detectable, and then only if they are being produced by something else: either as decay products of some long-lived isotope, or by cosmic-ray bombardment.&lt;/p&gt;&#xA;&lt;p&gt;An example is &lt;a href=&quot;https://en.wikipedia.org/wiki/Isotopes_of_gadolinium&quot; rel=&quot;nofollow noreferrer&quot;&gt;gadolinium-150&lt;/a&gt;. This has a half-life of about 1.8 million years, and I believe simply does not occur naturally at all.  Gadolinium-152, with a half-life of about &lt;span class=&quot;math-container&quot;&gt;$10^{14}$&lt;/span&gt; years, does occur naturally.&lt;/p&gt;&#xA;&lt;p&gt;So whatever primordial gadolinium-150 there was has gone (in 4 billion years, you get a decrease of a factor of about &lt;span class=&quot;math-container&quot;&gt;$10^{669}$&lt;/span&gt;: the Earth contains around &lt;span class=&quot;math-container&quot;&gt;$10^{50}$&lt;/span&gt; atoms, so there is a chance of &lt;span class=&quot;math-container&quot;&gt;$1/10^{619}$&lt;/span&gt; of finding an atom of it on Earth).  Unfortunately in order to know how much there was you would need to understand nucleosynthesis in supernovae in considerable detail (gadolinium is heavier than iron and so originated mostly or entirely in supernovae), and I don't.  But I think it's safe to say that they probably made at least some, on the grounds that anything we do in the way of crashing particles into things to make isotopes (which we have done to make &lt;span class=&quot;math-container&quot;&gt;$^{150}\mathrm{Gd}$&lt;/span&gt;) supernovae also do, except much, much more.  If we assume the Earth was only a million years old, then about &lt;span class=&quot;math-container&quot;&gt;$68\%$&lt;/span&gt; of the primordial &lt;span class=&quot;math-container&quot;&gt;$^{150}\mathrm{Gd}$&lt;/span&gt; would still be here: we'd find it.&lt;/p&gt;&#xA;&lt;p&gt;Now of course, there are two catches here:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;perhaps the &lt;span class=&quot;math-container&quot;&gt;$^{150}\mathrm{Gd}$&lt;/span&gt; has all gone somewhere secret where we can't find it;&lt;/li&gt;&#xA;&lt;li&gt;this all rests on the idea of supernova nucleosynthesis.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;So to answer the first: if this was true it would be utterly extraordinary.  In particular we spend a lot of time (really a lot of time) trying to isolate different isotopes of elements: people go to really enormous efforts to distinguish between different isotopes of uranium for instance.  This is something you can't do chemically, because the different isotopes have the same chemical properties.  Instead you have to do things like spin them in &lt;a href=&quot;https://en.wikipedia.org/wiki/Gas_centrifuge&quot; rel=&quot;nofollow noreferrer&quot;&gt;very high-speed centrifuges&lt;/a&gt;, or use mass spectrometers.  These things just don't exist naturally on Earth, so, since we do find other isotopes of gadolinium (including &lt;span class=&quot;math-container&quot;&gt;${}{150}\mathrm{Gd}$&lt;/span&gt;, which is not stable), how come we don't find this one?  Well, we don't find it because it's not there, of course.&lt;/p&gt;&#xA;&lt;p&gt;The second problem is perhaps more severe: people who believe the Earth is a million years old probably have no truck with supernovae at all, or are happy to just argue that, well, supernovae don't produce some isotopes because they just don't.  I don't think there's a useful argument against that.&lt;/p&gt;&#xA;" OwnerDisplayName="user18801" LastActivityDate="2020-06-20T17:13:42.350" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19854" PostTypeId="1" AcceptedAnswerId="19860" CreationDate="2020-06-21T09:33:39.027" Score="3" ViewCount="226" Body="&lt;p&gt;I came across an infrared weather map like this&#xA;&lt;a href=&quot;https://i.stack.imgur.com/oAS7I.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oAS7I.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I couldn't find any legend on the colorbar's color convention. Initially, I thought that might be the&#xA;color for reflected light's wavelength, but there was no way to find out.&#xA;This image is obtained from &lt;a href=&quot;https://mausam.imd.gov.in/imd_latest/contents/satellite.php#&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://mausam.imd.gov.in/imd_latest/contents/satellite.php#&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="20633" LastActivityDate="2020-06-22T23:46:24.617" Title="Understanding the color coding of a weather map" Tags="|meteorology|weather-satellites|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19855" PostTypeId="2" ParentId="19854" CreationDate="2020-06-21T10:03:19.630" Score="0" Body="&lt;p&gt;Op: You have posted an infrared image, but your question and the link with its the legend is about visible light images. Though similar rules apply, the outcome is fundamentally different, e.g. dark sea and light landmass on visible, vice versa on infrared during day.&lt;/p&gt;&#xA;&lt;p&gt;To the link: it is a visible light and not an infrared image. Though it is close to near infrared, it does not show a temperature equivalent, but from the legend one can take that the scale is (most probably) based on the amount of &lt;a href=&quot;https://en.wikipedia.org/wiki/Albedo&quot; rel=&quot;nofollow noreferrer&quot;&gt;diffuse reflected light&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;To teh image posted in the question: that'S an infrared image. Both show different things. I suggest you tell them apart, and decide if you want information about infrared or visible light.&lt;/p&gt;&#xA;&lt;p&gt;The linked wiki article illustrates the reflectivity of different surfaces (visible light), cumulus clouds are very bright, stratus and cirrus gather around the middle of the diagram, while water surfaces reflect much less and so appear darker.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-06-22T23:46:24.617" LastActivityDate="2020-06-22T23:46:24.617" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19857" PostTypeId="1" CreationDate="2020-06-22T08:01:10.483" Score="1" ViewCount="59" Body="&lt;p&gt;I read in a paper that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Interpretation of 2-D seismic lines shows the lower to middle&#xA;Patchawarra Formation onlapping onto paleostructural highs at&#xA;approximately 270 Ma and again at 273 Ma, suggesting two periods of&#xA;uplift.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Can someone please explain to me how uplift leads to onlapping?&lt;/p&gt;&#xA;" OwnerUserId="20637" LastEditorUserId="11430" LastEditDate="2020-06-30T08:01:04.407" LastActivityDate="2020-06-30T08:01:04.407" Title="How does uplift lead to onlapping?" Tags="|geology|seismic|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19858" PostTypeId="1" CreationDate="2020-06-22T10:24:40.633" Score="3" ViewCount="46" Body="&lt;p&gt;I have found this very long book from weather.gov (free access)  &lt;a href=&quot;https://www.weather.gov/media/epz/mesonet/CWOP-WMO8.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Guide to Meteorological Instruments and Methods of Observation&lt;/a&gt; which might be a bit too in-depth for what I'm looking for, so I was wondering which other resources are available (bonus points for the ones with free access).&lt;/p&gt;&#xA;" OwnerUserId="20566" LastActivityDate="2020-06-22T10:24:40.633" Title="Books / resources on measurement methods in atmospheric sciences" Tags="|meteorology|measurements|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19860" PostTypeId="2" ParentId="19854" CreationDate="2020-06-22T17:26:23.460" Score="2" Body="&lt;p&gt;Unfortunately it's common for satellite data services to show these types of images qualitatively, omitting the units or even a colorbar.&lt;/p&gt;&#xA;&lt;p&gt;This is an infrared image from the 10.8 micron channel (TIR1) of INSAT-3D.  That website you link to is a bit misleading because (for me at least) following the link puts the text describing the 0.65 micron visible channel under the image.  If you click &amp;quot;Infrared&amp;quot; in the sidebar of that page the text is replaced with the correct text about the 10.8 micron channel.&lt;/p&gt;&#xA;&lt;p&gt;Given that TIR1 records are stored as 10-bit values (i.e., in the range 0 to 1023) and the color scale maxes out at 939, I suspect that they are just plotting the raw count data.  This is normally transformed into radiances by applying a linear scale and offset to put the data in physical units.&lt;/p&gt;&#xA;&lt;p&gt;I had a quick look at the equivalent 10.8 micron image from Meteosat over the Indian Ocean (see below) and I get a similar count range and a similar image when I apply their color scale.  I also suspect that they've inverted their data, e.g., plotted &lt;code&gt;count_inv = 1024 - count&lt;/code&gt;, to fit with the viewers' expectation that cold clouds appear white.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YemYG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YemYG.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2020-06-22T17:26:23.460" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19862" PostTypeId="1" CreationDate="2020-06-23T04:09:37.710" Score="1" ViewCount="549" Body="&lt;p&gt;So Earth has an axial tilt and that creates weather regions. For example, approximately 23 degrees north and south, approximately the same as the planet's axial tilt, will give you the tropics. This creates a band around the Earth of warm wet climate. But then there are these climate cells as well. The Hadley cell occurs at 30 degrees north and south. This apparently creates low pressure and high pressure zones of hot air rising, condensing with rain, falling and cooling, etc.&lt;/p&gt;&#xA;&lt;p&gt;So what is the difference between the 23 degrees and the 30 degrees? I thought that the tropics are created because of the 23 degrees of tilt which also causes seasons? But then the tropics are also created because of Hadley cells?? They seem to have the same result with 2 completely different causes. Why are there both?  And what happens between 23 and 30 degrees?&lt;/p&gt;&#xA;" OwnerUserId="20642" LastEditorUserId="6298" LastEditDate="2021-07-24T03:05:49.903" LastActivityDate="2021-07-25T23:43:58.367" Title="How are climate regions caused by both axial tilt and also by climate circulation cells?" Tags="|meteorology|climate|climate-models|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19866" PostTypeId="1" CreationDate="2020-06-23T18:21:30.987" Score="1" ViewCount="53" Body="&lt;p&gt;I am aware that iron is a magnetic mineral and through the process of thermoremanent magnetization it can store a record to the state of magnetization it formed in.&lt;/p&gt;&#xA;&lt;p&gt;I wanted to ask if there are any phenomena or explanations to a negative correlation between the iron concentration and the magnetic field, i.e when the iron concentration increases the observed magnetic field from orbit decreases.&lt;/p&gt;&#xA;" OwnerUserId="18103" LastEditorUserId="2470" LastEditDate="2020-06-23T19:56:26.833" LastActivityDate="2020-06-23T19:56:26.833" Title="More iron = Less remanent magnetic field" Tags="|geomagnetism|paleomagnetism|rock-magnetism|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19867" PostTypeId="2" ParentId="19845" CreationDate="2020-06-24T20:03:52.283" Score="3" Body="&lt;p&gt;My ansatz for what &lt;code&gt;cyl&lt;/code&gt; means is likely Equidistant Cylindrical Projection, because &lt;a href=&quot;https://matplotlib.org/basemap/users/cyl.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;in the older Basemap module, &lt;code&gt;'cyl'&lt;/code&gt; was the shortname for that projection&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;But the reality is that since the GFS is a global spectral model with a latitude-longitude grid, it likely does not require a CRS. That is, it presupposes a sphere, where a CRS projects the spherical coordinates (latitude, longitude) onto a shape (such as a cone).&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorDisplayName="user1066" LastEditDate="2020-06-26T07:55:10.267" LastActivityDate="2020-06-26T07:55:10.267" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19868" PostTypeId="1" CreationDate="2020-06-24T20:20:38.030" Score="3" ViewCount="27" Body="&lt;p&gt;I'm exploring different places on the countryside and would like to compare their different annual temperatures. The options that I've seen are either too coarse (NASA, NOAA, arcgis (free online version)) or I need to pay (open weather)&lt;/p&gt;&#xA;&lt;p&gt;It seems google earth had this feature at some point with an alliance with the Weather Company &lt;a href=&quot;https://medium.com/google-earth/temperature-radar-wind-speed-explore-weather-data-in-google-earth-a7610e8c8eae&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://medium.com/google-earth/temperature-radar-wind-speed-explore-weather-data-in-google-earth-a7610e8c8eae&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20653" LastActivityDate="2020-06-24T20:20:38.030" Title="Is there a site where I could get a high resolution global annual temperature map?" Tags="|climate|temperature|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19870" PostTypeId="1" CreationDate="2020-06-25T05:59:15.593" Score="3" ViewCount="60" Body="&lt;p&gt;I am looking for observed sub-daily weather data (as 1d time series) which must include temperature, humidity, solar radiation and wind speed for a any location on earth. Currently I am aware of &lt;a href=&quot;https://www.bgc-jena.mpg.de/wetter/Weatherstation.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Jena city&lt;/a&gt; data which is available as open source. Can anyone mention another source?&lt;/p&gt;&#xA;" OwnerUserId="5557" LastEditorUserId="5557" LastEditDate="2020-06-26T00:30:07.533" LastActivityDate="2020-06-26T00:30:07.533" Title="Any open source sub-daily weather data other than Jena?" Tags="|open-data|evaporation|weatherdata|" AnswerCount="0" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="19871" PostTypeId="2" ParentId="19862" CreationDate="2020-06-25T09:24:10.960" Score="0" Body="&lt;p&gt;Generally speaking, the tropics are a geographical term. It's the area on the surface of the planet where at least once a year the Sun passes directly overhead.&lt;/p&gt;&#xA;&lt;p&gt;It has relation to climate, but even then within the tropical region you have a variety of climate zones from rain-forests all the way to savannas and deserts. Being in tropical region only ensures that it's generally warm all year round, other parameters define the actual climate type. Take a look &lt;a href=&quot;https://en.wikipedia.org/wiki/K%C3%B6ppen_climate_classification&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; at the range of climate types available in the tropics.&lt;/p&gt;&#xA;&lt;p&gt;Now, coming to Hadley cells and how they relate to tropics - they are not directly related to one another, i.e. one of them is not used to define the other.&lt;/p&gt;&#xA;&lt;p&gt;In &lt;a href=&quot;https://en.wikipedia.org/wiki/Hadley_cell&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hadley cell&lt;/a&gt; the humid air rises and moves north or south depending whether it started north or south of the equator and then sinks to the surface at around 30 degrees north and south of equator. So they are both dependent on the same factors, namely the simple fact that it's generally hot in the tropical region.&lt;/p&gt;&#xA;&lt;p&gt;What happens between 23 and 30 degrees really depends on where in the world you are. If you're between 23 and 30 degrees in North Africa, it's very unpleasant, because Sahara is right there. Other places are different depending on their own geographical and climate parameters.&lt;/p&gt;&#xA;" OwnerUserId="18158" LastActivityDate="2020-06-25T09:24:10.960" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19875" PostTypeId="2" ParentId="18611" CreationDate="2020-06-25T23:41:51.590" Score="1" Body="&lt;p&gt;Much of the methyl mercury that enters the atmosphere may be &lt;strong&gt;dimethyl mercury&lt;/strong&gt;, &lt;span class=&quot;math-container&quot;&gt;$\text{(CH}_3\text{)}_2\text{Hg}$&lt;/span&gt;.  This is a very volatile compound which, if it were pure, would have &lt;a href=&quot;https://www.osha.gov/dts/hib/hib_data/hib19980309.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;50 mm mercury or more&lt;/a&gt; vapor pressure at 20°C.  Complexes involving more electronegative ligands, such as the chloride &lt;span class=&quot;math-container&quot;&gt;$\text{CH}_3\text{HgCl}$&lt;/span&gt;, are significantly less volatile, but still have more vapor pressure than purely inorganic mercury compounds.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2020-06-25T23:41:51.590" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19876" PostTypeId="1" CreationDate="2020-06-26T07:51:42.790" Score="1" ViewCount="250" Body="&lt;p&gt;Some textbooks say that atmosphere extends up to 1600 km, but exosphere is more than  9000 km thick.&lt;br /&gt;&#xA;Where is the mistake?&lt;/p&gt;&#xA;" OwnerDisplayName="George carlin" LastEditorUserId="18081" LastEditDate="2020-06-26T08:40:06.783" LastActivityDate="2020-06-27T15:16:12.970" Title="Is Earth's atmosphere 1600 km thick?" Tags="|atmosphere|earth-system|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19877" PostTypeId="1" CreationDate="2020-06-26T10:14:09.340" Score="1" ViewCount="172" Body="&lt;p&gt;I live in Hong Kong. As a nature lover, I often spend time visiting the south-eastern coasts of Sai Kung Peninsular - a local nature reserve.&lt;/p&gt;&#xA;&lt;p&gt;The area's famous feature is the coastal erosion landscape. Sea arches and caves are present on almost every island off the coast. See the map below for the locations of major sea arches in the area.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/djdss.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/djdss.jpg&quot; alt=&quot;map&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;A point to note is that the entire area was once a super volcano 140 millions years ago, and most of the rocks found in the area are basalt. There are several locations where basalt columns reaches over 50 meter tall, and over 2 meters in diameter. One example is Po Pin Island - technically a sea stack - with a basalt column cliff cut so deep that it almost look like someone cut the island in half with a knife.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7cvoH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7cvoH.jpg&quot; alt=&quot;Po Pin Island&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;All the sea arches, sea caves and cliffs are semi-submerged. One can row a boat through some of these sea arches. Below are some images of these sea arches for your better understanding of their scale and the adjacent environment.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/90PUg.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/90PUg.jpg&quot; alt=&quot;Sea Arch 1&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/XKR6Z.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XKR6Z.jpg&quot; alt=&quot;Sea Arch 2&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/wmH7T.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wmH7T.jpg&quot; alt=&quot;Sea Arch 3&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/GZexV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GZexV.jpg&quot; alt=&quot;Sea Arch 4&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Note that despite the erosion of coastline, the mountain above the affected area are quite smooth and have retained enough soil to support plant growth. It appears that wind erosion has much less effect on these rocks compare to oceanic erosion.&lt;/p&gt;&#xA;&lt;p&gt;It is only reasonable to assume that these sea arches and caves are formed under the strong erosion forces from the ocean. However, to form such a large opening in basalt rocks takes time. While I cannot find any study on the estimated time required for such landscapes to form, I assume it will take tens of thousands of years.&lt;/p&gt;&#xA;&lt;p&gt;Now comes the problem - the sea level was no where near its current level in the past. Currently, even at several kilometres away from the coastline, the sea floor is merely 30-40 meters deep, where it could have been land ten thousand years ago. In fact, there are evidence that there existed some stone age primitive villages within Mirs Bay (see the location on the map above). It is then washed away or submerged when the sea level rises to current level.&lt;/p&gt;&#xA;&lt;p&gt;Given this record on sea level changes, the current coastline, including the sea arches and caves, has only around 10000 years to evolve from a relatively smooth mountain ridge into the state we see today. This is a very short time in geological scale. It is baffling that such significant erosion can manifest within just 10000 years.&lt;/p&gt;&#xA;&lt;p&gt;Grateful if any professionals can look into this question and explain how could this happen.&lt;/p&gt;&#xA;" OwnerUserId="20659" LastActivityDate="2020-06-26T10:14:09.340" Title="The seemingly impossible formation time for the local sea arches and caves" Tags="|sea-level|erosion|weathering|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19878" PostTypeId="1" AcceptedAnswerId="19882" CreationDate="2020-06-26T14:02:15.357" Score="3" ViewCount="163" Body="&lt;p&gt;I recently learn about &amp;quot;global stilling&amp;quot;, i.e. the fact that surface wind speed tends to decrease since the 80s. It was in &lt;a href=&quot;https://doi.org/10.1038/ngeo979&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt;, but it's from 2010. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Global_terrestrial_stilling&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia page&lt;/a&gt; also seems a bit outdated, as it mentions the STILLING project as &amp;quot;current&amp;quot; (it ended in 2018). Said project has only &lt;a href=&quot;https://cordis.europa.eu/project/id/703733/results&quot; rel=&quot;nofollow noreferrer&quot;&gt;one publication&lt;/a&gt;, although interesting (it suggests that part of the trend is an artefact from anemometers not ageing well!). So I was wondering what were the latest developments in this field? Do we now have a better idea of what could cause this phenomenon?&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-06-26T17:23:43.883" Title="What are the latest developments about global stilling?" Tags="|climate|wind|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19879" PostTypeId="1" CreationDate="2020-06-26T14:29:20.077" Score="2" ViewCount="2712" Body="&lt;p&gt;At standard conditions, one liter of air, 0.21 L of oxygen gas, contains 0.0094 moles of &lt;span class=&quot;math-container&quot;&gt;$\rm O_2$&lt;/span&gt;. What is the total quantity of oxygen gas molecules in the atmosphere?&lt;/p&gt;&#xA;" OwnerUserId="20661" LastEditorUserId="20661" LastEditDate="2020-06-26T16:06:02.963" LastActivityDate="2020-12-28T13:17:04.847" Title="How many mole of oxygen gas is there in the atmosphere?" Tags="|atmosphere|oxygen|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19880" PostTypeId="2" ParentId="19879" CreationDate="2020-06-26T16:03:31.327" Score="0" Body="&lt;p&gt;&lt;a href=&quot;https://www.newscientist.com/article/mg15020308-500-the-last-word/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.newscientist.com/article/mg15020308-500-the-last-word/&lt;/a&gt; says the atmosphere weighs 5 × 10^21 grams. The molar weight of oxygen gas is 32 gram per mole. Based on that estimate for the weight of atmosphere, the total quantity of O2 in atmosphere is around 5*10^21/32 = 1.5625e+20 mole.&lt;/p&gt;&#xA;" OwnerUserId="20661" LastActivityDate="2020-06-26T16:03:31.327" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19881" PostTypeId="2" ParentId="19879" CreationDate="2020-06-26T16:17:37.640" Score="2" Body="&lt;p&gt;It is easier to calculate:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The pressure of air on the ocean level is &lt;span class=&quot;math-container&quot;&gt;$\approx 100 \rm {kPa}$&lt;/span&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Thus, its weight is &lt;span class=&quot;math-container&quot;&gt;$\approx$&lt;/span&gt; 100000N over &lt;span class=&quot;math-container&quot;&gt;$1 \rm m^2$&lt;/span&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Considering that the overwhelming majority of the atmosphere is below some km over the surface of the Earth, we can ignore the decrease of the gravity with height.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Now calculate the mass of the air above a square meter (ten tons). And multiple it with the surface of the Earth (in square meters). Then, divide it with the mean molar mass of air and multiple with the partial pressure of &lt;span class=&quot;math-container&quot;&gt;$\ce{O2}$&lt;/span&gt; in it (&lt;span class=&quot;math-container&quot;&gt;$\approx$&lt;/span&gt; 29%).&lt;/p&gt;&#xA;" OwnerUserId="6016" LastEditorUserId="6016" LastEditDate="2020-12-28T13:17:04.847" LastActivityDate="2020-12-28T13:17:04.847" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19882" PostTypeId="2" ParentId="19878" CreationDate="2020-06-26T17:07:39.607" Score="2" Body="&lt;p&gt;It seems to be a thing of the past. Apparently around 2010 the 30 years calming trend reversed. Since then, wind speeds and wave heights are picking up quickly, possibly in a decadal variation pattern.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://science.sciencemag.org/content/332/6028/451&quot; rel=&quot;nofollow noreferrer&quot;&gt;Young et. al. 2010 Global Trends in Wind Speed and Wave Height&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Possible application for the planning of wind turbines:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/s41558-019-0622-6&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zhenzhong Zeng et.al. 2019 A reversal in global terrestrial stilling and its implications for wind energy production&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;From the abstract of the latter:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;... we use wind data from in situ stations worldwide to show that the stilling reversed around 2010 and that global wind speeds over land have recovered. We illustrate that decadal-scale variations of near-surface wind are probably determined by internal decadal ocean–atmosphere oscillations, rather than by vegetation growth and/or urbanization as hypothesized previously. ...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Similar observations of an increasing trend over ocean surfaces, overlapping with the period of global stilling over land.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0964569116300850&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ching Wei Zheng et.al. 2016 Global oceanic wind speed trends&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Can only read the abstract of the latter. Would be interesting to investigate further the reason for the differing observation and modelling of sea- and land-wind speeds during the term.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-06-26T17:23:43.883" LastActivityDate="2020-06-26T17:23:43.883" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19884" PostTypeId="1" AcceptedAnswerId="19890" CreationDate="2020-06-27T12:42:07.487" Score="4" ViewCount="231" Body="&lt;p&gt;&lt;a href=&quot;https://books.google.co.in/books?id=WA9ST5S_2v0C&amp;amp;printsec=frontcover&amp;amp;dq=An+Introduction+to+Our+Dynamic+Planet&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=2ahUKEwiOwOmggKLqAhVH4zgGHW_pCYoQ6AEwAHoECAAQAg#v=onepage&amp;amp;q=An%20Introduction%20to%20Our%20Dynamic%20Planet&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;An Introduction to Our Dynamic Planet&lt;/a&gt; under section 2.4 &amp;quot;The origins of the atmosphere and hydrosphere&amp;quot;(Page 80) says on the topic of gases escaping from our atmosphere as:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Different gases have different molecular masses, so their average velocities are&#xA;different at a given temperature. In order for a planetary body to retain a particular&#xA;gas in its atmosphere for a period of time of the same order as the age of the Solar&#xA;System, the average velocity of the molecules in the gas should be less than about&#xA;one-sixth of the escape velocity. (If the average velocity exceeds one-sixth of the&#xA;escape velocity, a significant proportion of molecules will be moving faster, and will&#xA;be lost.) This condition is achieved on only a few planets and satellites.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I didn't really understand where did this &amp;quot; one-sixth of the escape velocity&amp;quot; figure come up from. Is there some rigorous mathematical derivation or physical significance of this figure? In the previous page, the book had introduced the concept of how the velocities of molecules for a gas follow the &lt;a href=&quot;https://en.wikipedia.org/wiki/Normal_distribution&quot; rel=&quot;nofollow noreferrer&quot;&gt;normal distribution&lt;/a&gt;, and only those molecules which have velocities greater than or equal to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Escape_velocity&quot; rel=&quot;nofollow noreferrer&quot;&gt;escape velocity&lt;/a&gt; of a planet can leave the surface(the formula for which was also shown). But I wasn't able to link this with the paragraph mentioned above. Any derivation/logic for this one-sixth figure would be welcome&lt;/p&gt;&#xA;" OwnerUserId="20668" LastActivityDate="2020-06-29T08:40:57.550" Title="Relation between molecular mass and retention of a gas on a planet" Tags="|atmosphere|geochemistry|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19885" PostTypeId="2" ParentId="19876" CreationDate="2020-06-27T12:42:41.363" Score="3" Body="&lt;p&gt;I agree with the comments; some upfront research would be good here, even at a basic level.  A good place to start is &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;this Wikipedia article&lt;/a&gt;, which gives not only atmospheric heights but also other characteristics such as composition and the behavior of molecules.&lt;/p&gt;&#xA;&lt;p&gt;In terms of heights the Wikipedia article suggests 700 km for the lower boundary of the exosphere, versus 1600 km in the question. Neither figure is really wrong because, of course, when you're dealing with atmospheres there is no hard and fast boundary between layers.&#xA;Similarly, the 10,000 km altitude given for the top of the exosphere, where it merges with the solar wind, is not hard and fast either; it depends on how you decide where the solar wind becomes dominant over the molecules bound by Earth's gravity.&lt;/p&gt;&#xA;&lt;p&gt;Moreover, the outer boundary of the exosphere, however you define it, should not really be considered spherical.  The solar wind moves outwards from the Sun, so the exosphere is compressed on the side facing the Sun and pulled out like the tail of a comet on the opposite side.  The same effect is seen with our (and other planets') &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnetosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;magnetosphere&lt;/a&gt;, because the solar wind also contains electrically charged particles.&lt;/p&gt;&#xA;&lt;p&gt;I hope I've whetted your appetite for more in-depth exploration.  Good luck!&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2020-06-27T15:16:12.970" LastActivityDate="2020-06-27T15:16:12.970" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19886" PostTypeId="1" AcceptedAnswerId="19887" CreationDate="2020-06-28T02:09:25.850" Score="4" ViewCount="77" Body="&lt;p&gt;Phosphate has a major role in biology and the biosphere. In its &amp;quot;abiotic&amp;quot; form, floating around in the oceans, lets say marine oceans to be specific, does it tend to be in the Na&lt;sub&gt;3&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt; form? If for example a cell floating around in the oceans were to absorb a phosphate from the oceans, would it be the acidic phase (bonded with hydrogen ions, like H&lt;sub&gt;3&lt;/sub&gt;PO&lt;sub&gt;4&lt;/sub&gt;) or, a sodium-phosphate (the completely disassociated anion phase seems unlikely.. )&lt;/p&gt;&#xA;" OwnerUserId="20661" LastEditorUserId="2470" LastEditDate="2020-06-28T07:32:21.133" LastActivityDate="2020-06-28T16:32:23.960" Title="Phosphate in the oceans, does it tend to bond with sodium?" Tags="|geochemistry|geobiology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19887" PostTypeId="2" ParentId="19886" CreationDate="2020-06-28T16:32:23.960" Score="1" Body="&lt;p&gt;The pH of ocean water is currently &lt;a href=&quot;https://www.epa.gov/ocean-acidification/understanding-science-ocean-and-coastal-acidification&quot; rel=&quot;nofollow noreferrer&quot;&gt;about 8.1&lt;/a&gt;, which lies between the second and third dissociation constants (&lt;a href=&quot;https://en.wikipedia.org/wiki/Phosphoric_acid&quot; rel=&quot;nofollow noreferrer&quot;&gt;7.20 and 12.37, respectively&lt;/a&gt;).  So most of the phosphate inthe ocean in its twice-dissociared form, as &lt;span class=&quot;math-container&quot;&gt;$\text {HPO}_4^{2-}$&lt;/span&gt;.  For comparison, our own blood is around pH &lt;a href=&quot;https://www.healthline.com/health/ph-of-blood&quot; rel=&quot;nofollow noreferrer&quot;&gt;7.4&lt;/a&gt;, so phosphate in our blood would be a mixture of &lt;span class=&quot;math-container&quot;&gt;$\text {HPO}_4^{2-}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\text {H}_2\text{PO}_4^-$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;In the EPA reference above, it is noted that the slightly lower pH today versus in the relatively past implies a larger increase in hydrogen ion concentration.  But it's worse than that.  Because of the way &lt;a href=&quot;https://en.wikipedia.org/wiki/Buffer_solution&quot; rel=&quot;nofollow noreferrer&quot;&gt;changing pH is coupled with changing dissociation of acids&lt;/a&gt; including phosphoric acid, a seemingly small change in pH could mean a lot more potentially acidic material (in the case of phosphate, &lt;span class=&quot;math-container&quot;&gt;$\text {H}_2\text{PO}_4^-$&lt;/span&gt; versus &lt;span class=&quot;math-container&quot;&gt;$\text {HPO}_4^{2-}$&lt;/span&gt;) in the oceans.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2020-06-28T16:32:23.960" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19890" PostTypeId="2" ParentId="19884" CreationDate="2020-06-29T08:40:57.550" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;I didn't really understand where did this &amp;quot;one-sixth of the escape velocity&amp;quot; figure come up from.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The &amp;quot;one-sixth of the escape velocity&amp;quot; a ballpark number. As a general rule, three sigma events (events that are three standard deviations from the mean) happen all the time, while twelve sigma events are so very, very rare that they can essentially be ruled out. Six sigma events are rare but do happen. In a logarithmic sense, six is halfway between three and twelve.&lt;/p&gt;&#xA;&lt;p&gt;A bit less hand-waving, &lt;a href=&quot;http://geosci.uchicago.edu/%7Ekite/doc/Catling_and_Kasting_ch_5.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;it can be shown&lt;/a&gt; that the Jean's escape flux (which is what your text is addressing) is proportional to &lt;span class=&quot;math-container&quot;&gt;$v_s \, (1+\left(v_e/v_s\right)^2)\,\exp\left({-\,\left(v_e/v_s\right)^2}\right)$&lt;/span&gt; , where &lt;span class=&quot;math-container&quot;&gt;$v_s$&lt;/span&gt; is the expected value of the magnitude of the three-dimensional velocity of the gas at the top of the exobase and &lt;span class=&quot;math-container&quot;&gt;$v_e$&lt;/span&gt; is the escape velocity at the top of the exobase. That factor of &lt;span class=&quot;math-container&quot;&gt;$\exp\left({-\,\left(v_e/v_s\right)^2}\right)$&lt;/span&gt; means that Jean's escape is extremely sensitive to changes in &lt;span class=&quot;math-container&quot;&gt;$v_s$&lt;/span&gt;.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-06-29T08:40:57.550" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19893" PostTypeId="1" CreationDate="2020-06-30T06:37:12.870" Score="4" ViewCount="145" Body="&lt;p&gt;According to this &lt;a href=&quot;https://www.dw.com/en/scotlands-whisky-industry-neer-a-drop-to-drink/a-53922633&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;, it is claimed that (emphasis is mine)&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;At Arbikie Distillery in Angus, scientists claim to have developed the world's first &amp;quot;climate positive&amp;quot; gin. By using garden peas instead of wheat, the company has eliminated the need for carbon-intensive fertilizers and can produce animal feed from the leftover material. Taken together, this gives the drink &lt;strong&gt;a negative carbon footprint&lt;/strong&gt;, Arbikie says.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I am having trouble understanding how the act of producing animal feed from the leftovers of a process results in a negative carbon footprint.&lt;/p&gt;&#xA;" OwnerUserId="13363" LastEditorUserId="6129" LastEditDate="2020-06-30T18:24:35.073" LastActivityDate="2020-07-01T08:24:29.887" Title="How does the act of producing animal feed from the leftovers of a process result in a negative carbon footprint?" Tags="|climate-change|climate|carbon-cycle|agriculture|" AnswerCount="1" CommentCount="7" ClosedDate="2020-07-03T01:53:12.993" ContentLicense="CC BY-SA 4.0" />
  <row Id="19894" PostTypeId="1" AcceptedAnswerId="19897" CreationDate="2020-06-30T16:13:03.843" Score="1" ViewCount="224" Body="&lt;p&gt;More specifically, can it be argued that satellite data are more reliable because they are direct measurements of physical quantities, while reanalysis data depend on the processing and merging of different datasets ?&lt;/p&gt;&#xA;" OwnerUserId="20566" LastActivityDate="2020-07-01T17:13:14.900" Title="In meteorology, are satellite data &quot;better&quot; than reanalysis data?" Tags="|meteorology|satellites|reanalysis|weather-satellites|research|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19895" PostTypeId="2" ParentId="19893" CreationDate="2020-07-01T02:21:40.957" Score="1" Body="&lt;p&gt;Its only marketing, not a science equation... It's saying that their gin gives back CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; from other gin which uses fertiliser, and saves a bit of crop space for livestock food. Overall, any crops tend deprive a region of carbon sinks and biodiversity.&lt;/p&gt;&#xA;&lt;p&gt;Cropland has reduced the worlds total CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; sinks by 50+ percent, so using 1 crop for 2 things saves CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; sinks, fertilizer and fossil fuel. Animal stock is intrinsically a climate change accelerator too, especially mammal stocks, which occupy forest space and produce methane and use forest space for hay bales and food crops. Saving surplus foods slightly reduces their impact, its reduces the CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; budget compared to non surplus feeds.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="18081" LastEditDate="2020-07-01T08:24:29.887" LastActivityDate="2020-07-01T08:24:29.887" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19896" PostTypeId="1" CreationDate="2020-07-01T05:52:02.463" Score="4" ViewCount="470" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Will increased level of ocean acidity lead to more frequent acid rain?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I searched on google and it says acid rain will have minor impact on ocean acidity, but I am not sure if increased ocean acidity will increase frequency.&lt;/p&gt;&#xA;" OwnerUserId="20684" LastActivityDate="2023-01-04T17:49:23.700" Title="Will increased level of ocean acidity lead to more frequent acid rain?" Tags="|oceanography|environmental-protection|acid-rain|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19897" PostTypeId="2" ParentId="19894" CreationDate="2020-07-01T17:13:14.900" Score="4" Body="&lt;p&gt;Unfortunately, your question has no answer. Both have errors. Both can be unreliable. Your choice really depends on how you plan on using them.&lt;/p&gt;&#xA;&lt;p&gt;Satellites instrument contain sources of error, such as bad observations (wildfires in the NIR), mapping problems (especially near the poles), and representation error. Don't underestimate those sources of error- &lt;a href=&quot;https://rmets.onlinelibrary.wiley.com/doi/full/10.1002/qj.830&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geer and Bauer found that representation error can result in errors in brightness temperature larger than 20 K&lt;/a&gt;. Reanalysis combines both observation errors and model errors. A good reanalysis will reduce the influence of both errors, but it is still ingrained into the product. Satellites still report back observations.&lt;/p&gt;&#xA;&lt;p&gt;Reanalyses can be unreliable. For example, &lt;a href=&quot;https://rmets.onlinelibrary.wiley.com/doi/10.1002/joc.5670&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper shows that TRMM and PERSIANN‐CDR were more reliable than CFSR or ERA-interim&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Maybe more significantly, they both actually report entirely different things. Satellites measure radiances which can be converted into more sensible variables, while reanalyses use a mathematical representation of the atmosphere and observations. So comparing these are a lot like comparing apples and oranges.&lt;/p&gt;&#xA;&lt;p&gt;Some other thoughts you may want to consider:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Is balance more important than truth? Reanalyses tend to be more meteorologically complete, therefore balanced. Satellites actually observe the earth system, so they will be more grounded in reality.&lt;/li&gt;&#xA;&lt;li&gt;What temporal resolution do you want? Reanalysis outputs are usually once every few hours, while the temporal resolution of satellites vary a large amount, in both number of observations per hour and when observations are taken (such as geostationary vs polar orbiting).&lt;/li&gt;&#xA;&lt;li&gt;What horizontal resolution do you want? Satellites may have a horizontal resolution modelers can only dream of (metaphorically speaking), but at the cost of the number of regions (for polar orbiting satellites) or consistency (for geostationary satellites).&lt;/li&gt;&#xA;&lt;li&gt;For what amount of time do you want data? The &lt;a href=&quot;https://rda.ucar.edu/datasets/ds626.0/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ERA-20C dataset&lt;/a&gt; can go back to 1900 and &lt;a href=&quot;https://rda.ucar.edu/datasets/ds131.2/&quot; rel=&quot;nofollow noreferrer&quot;&gt;the NOAA/CIRES dataset goes back to 1850&lt;/a&gt;, while &lt;a href=&quot;https://whyfiles.org/2010/how-long-have-satellites-been-used-to-study-earths-weather/index.html#:%7E:text=The%20first%20successful%20meteorological%20experiment,that%20measured%20Earth%27s%20heat%20balance.&quot; rel=&quot;nofollow noreferrer&quot;&gt;the first meteorological satellite was put up in 1959&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-07-01T17:13:14.900" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19898" PostTypeId="2" ParentId="19896" CreationDate="2020-07-01T22:45:22.823" Score="3" Body="&lt;p&gt;More likely, it works the other way: increased acid-forming compounds in the atmosphere are the cause of more ocean acidification.&lt;/p&gt;&#xA;&lt;p&gt;Pio et al. [&lt;a href=&quot;https://doi.org/10.1016/1352-2310(96)00059-3&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;] report measurements of sulfur and nitrogen compounds in air masses that they traced to either continental or oceanic origins.  They report that the lowest levels of these compounds were from ocean-origin air masses, indicating that the ocean is absorbing acid-rain causing pollutants such as sulfur dioxide.  Even so, levels of these compounds over the oceans has increased in recent years, likely from increased pollution on land.&lt;/p&gt;&#xA;&lt;p&gt;In &lt;a href=&quot;https://earthscience.stackexchange.com/a/19887/20607&quot;&gt;this answer&lt;/a&gt; it is noted that increasing acidity can alter the salt composition of the ocean, producing more acidic species (such as &lt;span class=&quot;math-container&quot;&gt;$\text{H}_2\text{PO}_4^-$&lt;/span&gt; ions).  However, these tend to remain dissolved in the water rather than evaporate into the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;Reference&lt;/p&gt;&#xA;&lt;p&gt;1.&#xA;Casimiro A. Pio, Mário A.Cerqueira, Luis M.Castro, Maria L.Salgueiro, &amp;quot;Sulphur and nitrogen compounds in variable marine/continental air masses at the southwest European coast&amp;quot;, Atmospheric Environment&#xA;Volume 30, Issue 18, September 1996, Pages 3115-3127.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2020-11-30T11:34:45.267" LastActivityDate="2020-11-30T11:34:45.267" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19900" PostTypeId="1" CreationDate="2020-07-02T18:09:13.550" Score="3" ViewCount="60" Body="&lt;p&gt;I'm interested in the visualization of the formation process of &amp;quot;strange&amp;quot; objects like &lt;a href=&quot;https://en.wikipedia.org/wiki/Wave_Rock&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wave Rock&lt;/a&gt; (flared slope). I've found articles describing hypotheses of the rock formation but I cannot find mathematical modeling (computer simulation) of it. Aren't modeling approaches of rocks popular in geomorphology because of complexity, long time periods to cover, and a lot of factors to take into account?&lt;/p&gt;&#xA;" OwnerUserId="20693" LastEditorUserId="20693" LastEditDate="2020-07-05T06:45:26.523" LastActivityDate="2020-07-05T06:45:26.523" Title="Is there a modelling of Wave Rock (Hyden Rock) formation?" Tags="|rocks|geomorphology|numerical-modelling|simulation|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19901" PostTypeId="1" AcceptedAnswerId="23805" CreationDate="2020-07-02T18:16:29.730" Score="7" ViewCount="283" Body="&lt;p&gt;I am following the paper to calculate UTCI using ERA5 meteorological variables.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://link.springer.com/article/10.1007/s00484-020-01900-5?shared-article-renderer&quot; rel=&quot;noreferrer&quot;&gt;https://link.springer.com/article/10.1007/s00484-020-01900-5?shared-article-renderer&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;In the paper, the authors have mentioned that they are using ERA5 product. And specifically mentioned to use the direct and diffuse component of shortwave (SW) radiation.&lt;/p&gt;&#xA;&lt;p&gt;The problem is, ERA5 data does not provide the direct and diffuse SW separately. Rather it only provides Surface solar radiation downwards which includes both the direct and diffuse component.&lt;/p&gt;&#xA;&lt;p&gt;My question would be, is there a way to calculate the direct and diffuse component of SW from ERA5. The dataset I have is similar to ERA5 and has the Downward SW and Net SW. I have no problem in obtaining the Long waves BTW.&lt;/p&gt;&#xA;&lt;p&gt;Any help would be much appreciated. TIA&lt;/p&gt;&#xA;" OwnerUserId="20694" LastActivityDate="2022-05-12T16:43:23.627" Title="Direct and Diffused component of shortwave radiation in ERA5 data" Tags="|atmosphere|atmospheric-radiation|era|energy-balance|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19902" PostTypeId="2" ParentId="19896" CreationDate="2020-07-03T09:35:43.700" Score="2" Body="&lt;p&gt;Essentially no. Acid rain was especially a problem when coal and other industries let up vast amount of sulphur which made strong sulphuric acid rain which could kill trees. Volcanoes can also have similar effects, and some industrial regions still create acid rain. There are maps available.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/2CE3M.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2CE3M.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So, as the energy industry becomes solar/wind based, there will be less acid rain.&lt;/p&gt;&#xA;&lt;p&gt;There is another source of acid in the rain, which is not due to the oceans: CO&lt;sub&gt;2&lt;/sub&gt; ... it causes the rain to wear down the mountains and it causes erosion. The rocks and alkaline minerals are one of the carbon sinks that bind to atmospheric CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Current CO&lt;sub&gt;2&lt;/sub&gt; emissions are around 40 billion tons a year; natural weathering absorbs roughly 1.1 billion tons.&lt;/p&gt;&#xA;&lt;p&gt;Higher CO&lt;sub&gt;2&lt;/sub&gt; in the air does make the rain more acid, it just dissolves alkaline rocks i.e. limestone a lot more efficiently.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="2470" LastEditDate="2023-01-04T17:49:23.700" LastActivityDate="2023-01-04T17:49:23.700" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19903" PostTypeId="2" ParentId="14342" CreationDate="2020-07-03T15:21:32.840" Score="2" Body="&lt;p&gt;In a sense, the full structure of a cumulus cloud extends all the way to the ground.  The cloud is formed from the convection of air rising off the ground.  The rising column becomes visible as a cloud when the atmospheric temperature becomes cold enough to condense water vapor, and the level where that occurs is the base we see.  From &lt;a href=&quot;https://en.wikipedia.org/wiki/Cumulus_cloud&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Cumulus clouds form via atmospheric convection as air warmed by the surface begins to rise. As the air rises, the temperature drops (following the lapse rate), causing the relative humidity (RH) to rise. If convection reaches a certain level the RH reaches one hundred percent, and the &amp;quot;wet-adiabatic&amp;quot; phase begins. At this point a positive feedback ensues: since the RH is above 100%, water vapor condenses, releasing latent heat, warming the air and spurring further convection.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In this phase, water vapor condenses on various nuclei present in the air, forming the cumulus cloud. This creates the characteristic flat-bottomed puffy shape associated with cumulus clouds.[1][&lt;a href=&quot;https://doi.org/10.1175%2F1520-0469%281947%29004%3C0091%3AEOAIAC%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;] The height of the cloud (from its bottom to its top) depends on the temperature profile of the atmosphere and the presence of any inversions.[&lt;a href=&quot;https://doi.org/10.1126%2Fscience.186.4164.632&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Cited References:&lt;/p&gt;&#xA;&lt;p&gt;1.&#xA;&amp;quot;Cumulus clouds&amp;quot;. Weather. 16 October 2005. Retrieved 16 October 2012.&lt;/p&gt;&#xA;&lt;p&gt;2.&#xA;Stommel, Harry (June 1947). &amp;quot;Entrainment of Air Into a Cumulus Cloud&amp;quot;. Journal of Meteorology. 4 (3): 91–94.&lt;/p&gt;&#xA;&lt;p&gt;3.&#xA;Mossop, S. C.; Hallett, J. (November 1974). &amp;quot;Ice Crystal Concentration in Cumulus Clouds: Influence of the Drop Spectrum&amp;quot;. Science Magazine. 186 (4164): 632–634.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2020-07-03T15:21:32.840" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19904" PostTypeId="2" ParentId="14342" CreationDate="2020-07-03T18:38:43.923" Score="3" Body="&lt;p&gt;I know this question has an answer confirmed, but I'll add my own comments for posterity's sake. There are different types of clouds. Buoyancy-driven (cumulus-type) clouds are the types that have the most definitive bases and ceilings.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The cloud base is approximately the &lt;a href=&quot;https://en.wikipedia.org/wiki/Lifted_condensation_level#:%7E:text=The%20lifted%20condensation%20level%20or,cooled%20by%20dry%20adiabatic%20lifting.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lifted Condensation Level&lt;/a&gt;, which is the height that the air near the surface would have to rise to to saturate.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;If the parcel of air can get to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Level_of_free_convection&quot; rel=&quot;nofollow noreferrer&quot;&gt;Level of Free Convection&lt;/a&gt;, then the parcel will continue to rise and accelerate until the parcel encounters more stable air. It then starts to decelerate.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The level where the parcel stops moving is called the &lt;a href=&quot;https://en.wikipedia.org/wiki/Equilibrium_level#:%7E:text=In%20meteorology%2C%20the%20equilibrium%20level,same%20temperature%20as%20its%20environment.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Equalibrium Level&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;There are other types of clouds with other formation mechanisms. Cirrus clouds, for example, occur when the clouds in the above process go so high that they reach freezing temperatures and are moved into other regions. Stratus clouds form in the above process when the parcel never reaches step 2. Fog may form from either &lt;a href=&quot;https://www.theweatherprediction.com/habyhints2/435/#:%7E:text=Advection%20fog%20is%20fog%20produced,even%20when%20it%20is%20windy.&quot; rel=&quot;nofollow noreferrer&quot;&gt;advection&lt;/a&gt; or &lt;a href=&quot;https://www.weather.gov/safety/fog-radiation#:%7E:text=Radiation%20fog%20is%20a%20very,reach%20saturation%2C%20fog%20will%20form.&quot; rel=&quot;nofollow noreferrer&quot;&gt;the air diabatically cools to reach saturation&lt;/a&gt;. &lt;a href=&quot;https://en.wikipedia.org/wiki/Kelvin%E2%80%93Helmholtz_instability&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kelvin-Helmholtz clouds form due to inertial instability.&lt;/a&gt; &lt;a href=&quot;https://en.wikipedia.org/wiki/Contrail&quot; rel=&quot;nofollow noreferrer&quot;&gt;Contrails&lt;/a&gt; form from the hot moist exhaust mixing with the cool, relatively dry atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-07-03T18:38:43.923" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19905" PostTypeId="1" CreationDate="2020-07-03T19:09:55.690" Score="1" ViewCount="24" Body="&lt;p&gt;From the measured values below, which ones are the most important factors that affect the amount of streamflow? (For short, mid, and long term)&#xA;Which ones are more important?&#xA;(Can give me some references to study?)&#xA;I am trying to build a climatic model.&lt;/p&gt;&#xA;&lt;p&gt;Temperature&#xA;Precipitation&#xA;humidity&#xA;wind speed&#xA;downward surface shortwave radiation&lt;/p&gt;&#xA;" OwnerUserId="20699" LastActivityDate="2020-07-03T19:09:55.690" Title="What are the most important climatic measurements to predict streamflow and water for short term, midterm and long term prediction?" Tags="|climate-models|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19907" PostTypeId="1" CreationDate="2020-07-03T20:48:50.127" Score="1" ViewCount="119" Body="&lt;p&gt;I am reading a book that argues that the Ancestral Puebloans settled along the rincons, or nooks, along the canyon walls, because that was where water was reliable. I can't understand the argument, as I think the canyon floor would be the place where water from every rincon flowed, and therefore would be far more reliable than getting water from just one nook along the canyon wall. Is there some validity to the author's argument?&lt;/p&gt;&#xA;" OwnerUserId="17645" LastEditorUserId="6467" LastEditDate="2020-07-10T14:57:33.070" LastActivityDate="2020-07-10T14:57:33.070" Title="Why would a rincon provide more reliable water?" Tags="|hydrology|water|" AnswerCount="0" CommentCount="2" ClosedDate="2020-07-14T18:15:04.917" ContentLicense="CC BY-SA 4.0" />
  <row Id="19908" PostTypeId="1" AcceptedAnswerId="19912" CreationDate="2020-07-03T20:53:02.277" Score="3" ViewCount="665" Body="&lt;p&gt;I am wondering if there is long term (10 year, 7 year, 20 year)  periodic patterns Similar to short term seasonal and periodic patterns in weather such as sea/land wind, monsoon, ENSO, ocean sea-saw, etc.&#xA;&lt;br&gt;&#xA;&lt;strong&gt;Specifically related to drought&lt;/strong&gt;&lt;br&gt;&#xA;I am trying to predict the rainfall using the weather data, I was wondering if different patterns that happen in weather changes through time are periodic?&#xA;Is there a periodic pattern in the pattern of weather changes?&#xA;Is there a general periodic pattern that may happen every 10 years or more? If so, how long is the window of this period?&#xA;Or a similar question can be: the weather measurements of how far ago can affect today's weather measurements?&#xA;Does the weather forget about the weather events of long time ago? If so, how long is that window?&lt;/p&gt;&#xA;&lt;p&gt;If there is a &lt;strong&gt;journal paper&lt;/strong&gt; or material that I can study please tell me. Thanks&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Additional Explanation:&lt;/strong&gt;&#xA;I am a data scientist trying to predict rainfall using weather data. So I do not have earth science knowledge. So after I read @Fred's comment, I understood that what I have in mind is called 'Cycle' in earth sciences.&#xA;&lt;br&gt;&#xA;&lt;strong&gt;edited question:&lt;/strong&gt; &lt;em&gt;What is the length of the cycles for rainfall patterns? (If I want to predict rainfall, how long is the length for cycles that affect rainfall? Or how many years of data I should use?! )&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="20699" LastEditorUserId="20699" LastEditDate="2020-07-04T14:56:53.223" LastActivityDate="2020-07-06T18:27:50.513" Title="Are weather changes periodic? (Do the same weather patterns repeat over years?) (Cycles) (Journal paper suggestion)" Tags="|weather-forecasting|precipitation|rainfall|" AnswerCount="1" CommentCount="10" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19909" PostTypeId="1" AcceptedAnswerId="19910" CreationDate="2020-07-05T04:26:26.163" Score="1" ViewCount="94" Body="&lt;p&gt;Alert, in Qikiqtaaluk Region, Nunavut, Canada, is northernmost permanently inhabited place in world.&lt;/p&gt;&#xA;&lt;p&gt;The site was first visited by Sir George Nares, who commanded HMS Alert in 1875-76, the first vessel to land on the shores of northern Ellesmere Island.&lt;/p&gt;&#xA;&lt;p&gt;Is Alert a harbor/port? (I've read a few papers about Alert, but I haven't found the answer.)&lt;/p&gt;&#xA;" OwnerUserId="20701" LastActivityDate="2020-07-07T19:57:58.453" Title="Is Alert (in Canada) a harbor/port?" Tags="|arctic|coastal|canada|transportation|" AnswerCount="1" CommentCount="3" ClosedDate="2020-07-23T04:44:25.297" ContentLicense="CC BY-SA 4.0" />
  <row Id="19910" PostTypeId="2" ParentId="19909" CreationDate="2020-07-05T20:45:11.670" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_ports_and_harbors_of_the_Arctic_Ocean&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; does not include Alert as a port.  As the comments suggest, there is too much sea ice at that latitude to merit the infrastructure required of a port.  The northernmost port in the world is identified &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_ports_and_harbors_of_the_Arctic_Ocean&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; as Dikson, Russia, at 73°30' N.&lt;/p&gt;&#xA;&lt;p&gt;Supplies to Alert are delivered by air; the settlement does include an &lt;em&gt;air&lt;/em&gt; port.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="6467" LastEditDate="2020-07-07T19:57:58.453" LastActivityDate="2020-07-07T19:57:58.453" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19912" PostTypeId="2" ParentId="19908" CreationDate="2020-07-06T18:27:50.513" Score="0" Body="&lt;p&gt;I'll address this part of the question first:&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Or a similar question can be: the weather measurements of how far ago can affect today's weather measurements? Does the weather forget about the weather events of long time ago? If so, how long is that window?&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;The answer is &amp;quot;approximately two weeks&amp;quot;. Even with &lt;em&gt;nearly perfect&lt;/em&gt; knowledge of the atmospheric state (the distribution of pressure, moisture, aerosols, etc), the chaotic nature of fluids means that beyond two weeks, one would be better of predicting the weather from a climatological estimate (i.e, the average of the weather on that date for the last ~30 years). Research into this very question was foundational for the field of Chaos theory (Lorenz, 1963 is a famous example). This isn't just an artifact of the predictive models, but the natural system itself. The weather has effectively 'forgotten' what it was doing a few weeks before.&lt;/p&gt;&#xA;&lt;p&gt;While the atmosphere has a short 'memory', other parts of the Earth have longer 'memories'. Notable examples are the Oceans and the Landsurface. A warm anomaly in the Ocean will stick around for a while, since ocean currents are much slower than air for mixing things around (and diffusing out the anomaly). The atmosphere is very influenced by what happens on the surface, so the warm/cool anomaly can affects the weather in various ways. This is what happens in the case of ENSO that you have mentioned. The land can also have an impact. The amount of saturation in the soil can have quite a big impact on weather, especially for things like thunderstorms and monsoon systems. Continental snow cover extent may also impact atmospheric predictability. Stratosphere/troposphere coupling mechanisms might also be a source of longer term predictability.&lt;/p&gt;&#xA;&lt;p&gt;And this part:&#xA;&amp;quot;I am wondering if there is long term (10 year, 7 year, 20 year) periodic patterns Similar to short term seasonal and periodic patterns in weather such as sea/land wind, monsoon, ENSO, ocean sea-saw, etc.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;The most well known ~10 year climate oscillation is the Pacific Decadal Oscillation.&lt;/p&gt;&#xA;" OwnerUserId="6735" LastActivityDate="2020-07-06T18:27:50.513" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19913" PostTypeId="1" AcceptedAnswerId="19914" CreationDate="2020-07-06T23:07:49.077" Score="1" ViewCount="149" Body="&lt;p&gt;I am relatively new to Python, and I am having trouble plotting some data. Specifically, I am plotting wind speed data on a 2-D plot that I grabbed from the Weather Research &amp;amp; Forecasting (WRF) weather model. Though I'm able to generate a plot, there are noticeable gaps in plot, particularly as the model height increases. The purpose of generating these plots is to compare WRF model data to observations collected from dropsondes during a field campaign. Below is the code that I've been working with as well as the plot that was generated.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import numpy as np&#xA;from netCDF4 import Dataset&#xA;import wrf&#xA;from wrf import getvar&#xA;import glob&#xA;import pandas as pd&#xA;import matplotlib.pyplot as plt&#xA;&#xA;dir = glob.glob('~/wrfout_d04_2017-05-27_20:00:00')&#xA;dir.sort()&#xA;nf = range(0,len(dir),6)&#xA;&#xA;for n in nf:&#xA;  data = Dataset(dir[n], 'r')&#xA;  windspeed = wrf.getvar(data, 'uvmet_wspd_wdir', meta = False)[0,:]&#xA;  winddir = wrf.getvar(data, 'wdir', meta = False)&#xA;  altitude = wrf.getvar(data, 'z', meta = False)&#xA;  lat = wrf.getvar(data, 'lat', meta = False)&#xA;  lon = wrf.getvar(data, 'lon', meta = False)&#xA;&#xA;  for i in range(len(windspeed)):&#xA;    fig = plt.figure&#xA;    plt.plot(windspeed[i], altitude[i], color = 'blue')&#xA;    plt.axis('tight')&#xA;    plt.xlabel('Wind speed (m/s)')&#xA;    plt.ylabel('Height (m)')&#xA;    plt.title('Wind speed and model height for\nwrfout_d04_2017-05-27_20:00:00')&#xA;  i+=1&#xA;  plt.show()&#xA;  plt.savefig('wrf_windspeed.png')&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/y9cQa.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/y9cQa.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I've tried checking to see if the WRF output file 'wrfout_d04_2017-05-27_20:00:00' contains masked data using ncdump -h wrfout_d04_2017-05-27_20:00:00, but I'm not seeing anything there. I really appreciate anyone taking the time to read this post and any recommendations would be greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="20707" LastActivityDate="2020-07-08T02:52:47.583" Title="Wind speed data plot contains blank gaps" Tags="|meteorology|wrf|python|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19914" PostTypeId="2" ParentId="19913" CreationDate="2020-07-08T02:52:47.583" Score="2" Body="&lt;p&gt;The answer is actually pretty easy. The WRF model lies on a grid. The vertical component of the grid is unevenly spaced, though you can manually space it. The vertical coordinate of WRF uses a sigma vertical coordinate (even though the namelist calls them eta): &lt;span class=&quot;math-container&quot;&gt;$$\sigma=\frac{P-P_{surface}}{P_{top}-P_{surface}}$$&lt;/span&gt;. So the values of sigma are specified (or just resorted to the default values). So when you get altitude levels for WRF, there is a space between the levels. You would probably find something similar if you change the y-axis to west-east or south-north.&lt;/p&gt;&#xA;&lt;p&gt;The default vertical spacing for WRF has higher resolution near the surface, which is useful for convection and PBL modeling.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-07-08T02:52:47.583" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19916" PostTypeId="1" CreationDate="2020-07-08T13:57:03.403" Score="1" ViewCount="49" Body="&lt;p&gt;I have an 8 foot diameter weather balloon and I plan to launch it into near space. I was hoping someone out there in this community would know about weather balloons. My payload will problably weigh around 3 pounds. How much helium should I put in for maximum bursting point? Here’s a link to the balloon: &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/B004I45LX0&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weather balloon link&lt;/a&gt;. Thanks in advance!&lt;/p&gt;&#xA;&lt;p&gt;(I also asked this question on the space exploration community, in case anybody there has done this before.)&lt;/p&gt;&#xA;" OwnerUserId="20714" LastActivityDate="2020-07-08T13:57:03.403" Title="How much helium should I put in a weather balloon?" Tags="|meteorology|" AnswerCount="0" CommentCount="5" ClosedDate="2020-07-11T13:44:43.943" ContentLicense="CC BY-SA 4.0" />
  <row Id="19917" PostTypeId="1" AcceptedAnswerId="19922" CreationDate="2020-07-08T15:44:23.930" Score="1" ViewCount="2685" Body="&lt;p&gt;Given 6-hour rainfal data with units in meters(m), how can one convert the &lt;code&gt;6-hourly&lt;/code&gt; rainfall depth in &lt;code&gt;meters(m)&lt;/code&gt; to &lt;code&gt;1-hourly rainfall intensity or rate&lt;/code&gt; in &lt;code&gt;kg/m^2/s&lt;/code&gt;?&lt;/p&gt;&#xA;&lt;p&gt;Below is a sample data value to convert.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;rainfall depth (m)= 0.0014061&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;This is what I have tried but not sure it is correct:&lt;/p&gt;&#xA;&lt;p&gt;To convert the &lt;code&gt;6h&lt;/code&gt; value to the &lt;code&gt;hourly rate&lt;/code&gt;, I applied a multiplicative factor:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;factor=0.046296296 kg/m2/s&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;based on the reasoning that the equivalent to:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;m (in 6 hours) to mm/s = 1000/21600 (i.e. 0.0462963)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;How do I use the multiplicative factor (&lt;code&gt;0.046296296 kg/m2/s&lt;/code&gt;) to convert &lt;code&gt;6-hour rainfall depth to hourly&lt;/code&gt;?&lt;/p&gt;&#xA;&lt;p&gt;Maybe I am thinking too much here.&lt;/p&gt;&#xA;&lt;p&gt;Any thoughts?&lt;/p&gt;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="20715" LastActivityDate="2020-07-09T15:12:50.907" Title="Rainfall units conversion from depth to rate/intensity" Tags="|rainfall|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19919" PostTypeId="1" CreationDate="2020-07-09T04:40:45.780" Score="2" ViewCount="83" Body="&lt;p&gt;2020 is predicted to be an unusually warm year and we are already seeing a lot of unusual temperatures. I was wondering, how much of an impact the reduction of aerosol emission from the global lockdown had on this.&#xA;I am not a climate scientist, but as far as I understand it: Aerosols are a short lived byproduct of our industries which increases atmospheric reflectivity. Because of this less sunlight reaches the surface of the earth -&amp;gt; less warmth is created in the first place. Because they are so short-lived shutting down industries should result in an almost immediate reduction in atmospheric reflectivity -&amp;gt; more sunlight reaches the earth's surface -&amp;gt; more warmth is created.&#xA;That sounds like it makes sense in theory, but does it in praxis?&lt;/p&gt;&#xA;" OwnerUserId="20717" LastActivityDate="2020-07-09T12:56:18.257" Title="Is the lack of aerosols increasing temperatures in 2020?" Tags="|atmosphere|aerosol|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19920" PostTypeId="2" ParentId="19919" CreationDate="2020-07-09T09:08:33.263" Score="3" Body="&lt;p&gt;Depending on type and size of aerosol there can be scattering, (Mie- and Rayleigh- scattering), atmospheric windows filter radiation, we have absorption, transmission and transformation of wavelengths which all influence the amount of energy that's trapped or reflected back.&lt;/p&gt;&#xA;&lt;p&gt;The lockdown has led to a significant reduction of aerosols and drastic improvement of air quality in some regions (meaning not everywhere), but reliable studies seem to be rare atm. Evaluation is underway, but i think we must wait until a season has passed and activity has returned. A huge effect on temperature has afaik not yet been observed and described and if, it was towards a local decrease in temperature, not an increase. Anyway, the positive effects of lower economic activity are ceasing as no or little attempts are being made to use the reset for a transition to more sustainability.&lt;/p&gt;&#xA;&lt;p&gt;Two examples I found, so far:&lt;/p&gt;&#xA;&lt;p&gt;South-East Asia from satellite observation&#xA;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0048969720331788&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/S0048969720331788&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;... enforced lockdown at different degrees to contain the spread of the disease, which has brought some positive effects on natural environment.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Morocco, a slight (-0.3°C) reduction in temperaure, but higher variablity &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0048969720330588&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/S0048969720330588&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;... not much for day temperatures for beyond 40°C in the area.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;... the emissions from vehicle exhaust and industrial production were significantly reduced, which contribute to the decrease in the concentrations of the studied pollutants ... local emission reductions related to the lockdown were overwhelmed by the contribution of long-range transported aerosols outside areas.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;tl, dr:&#xA;No, probably not, it may locally temporarily lower the temperature by a tiny bit, but overall this effect seems to be shadowed. But future work will show, it is too early to be definitive because the story still develops.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-07-09T12:56:18.257" LastActivityDate="2020-07-09T12:56:18.257" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19921" PostTypeId="1" CreationDate="2020-07-09T14:02:41.927" Score="2" ViewCount="166" Body="&lt;p&gt;A recent &lt;a href=&quot;https://www.theguardian.com/environment/2020/jul/08/spreading-rock-dust-on-fields-could-remove-vast-amounts-of-co2-from-air?CMP=Share_iOSApp_Other&quot; rel=&quot;nofollow noreferrer&quot;&gt;Guardian article&lt;/a&gt; &amp;quot;Spreading rock dust on fields could remove vast amounts of CO&lt;sub&gt;2&lt;/sub&gt; from air&amp;quot; has gotten some attention in the nongovernmental and UN organizations working in the Sahel who are desperate to combat the adverse effects of climate change in the region. This article is based on a &lt;a href=&quot;https://www.nature.com/articles/s41586-020-2448-9&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nature&lt;/a&gt; publication on enhanced rock weathering (ERW).&lt;/p&gt;&#xA;&lt;p&gt;Let's pretend a large international organization has tasked a newly employed software developer to look into the feasibility of performing ERW in the Sahel. Now this let's say this software developer, who has no geological background whatsoever, is trying to figure out what it would take to run a ERW pilot in the Sahel and decided to investigate &lt;a href=&quot;https://www.google.com/maps/place/Bol,+Chad/@13.4694221,14.7031953,4529m/data=!3m2!1e3!4b1!4m8!1m2!2m1!1sKablewa+IDP!3m4!1s0x1110bf7f2511383b:0x9489d58a5875503c!8m2!3d13.4590796!4d14.71138&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bol, Chad&lt;/a&gt; to have a specific place to focus on.&lt;/p&gt;&#xA;&lt;p&gt;Ideally, this pilot would seek to test two things (i) is ERW feasible to perform in the region of conflict, (ii) does the crushed basalt or silicate, which is added to the soil, increase crop yield?&lt;/p&gt;&#xA;&lt;p&gt;In order to determine if this pilot is feasible to even consider I think the following should be investigated:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Current farming methods in the region&lt;/li&gt;&#xA;&lt;li&gt;Feasibility of acquiring and transporting crushed basalt or silicate&lt;/li&gt;&#xA;&lt;li&gt;Method for applying the basalt or silicate to the soil&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;What else should I look at?&lt;/p&gt;&#xA;&lt;p&gt;If you were given this (completely hypothetical) task where would you start?&lt;/p&gt;&#xA;&lt;p&gt;Is there any giant red flag I am missing which would be enough of a reason not to move forward with a pilot?&lt;/p&gt;&#xA;" OwnerUserId="20721" LastEditorUserId="2470" LastEditDate="2020-07-10T01:19:01.833" LastActivityDate="2020-07-21T09:30:42.327" Title="Using Enhanced Rock Weathering in the Sahel Region of Africa" Tags="|geology|climate-change|rocks|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19922" PostTypeId="2" ParentId="19917" CreationDate="2020-07-09T15:12:50.907" Score="4" Body="&lt;p&gt;Your 6-hour rainfall data represent the depth of water fallen in 6 hours. In order to have the average rainfall intensity in m/s corresponding to that interval of time, you have to divide the rainfall depth for the number of seconds in the time interval or for mm/s you multiply for 1000/21600. If you want the intensity in m/h you divide for 6 hours.&lt;/p&gt;&#xA;&lt;p&gt;You have only the cumulative rainfall in 6 hours so you can estimate the intensity dividing equally the volume of rainfall over the 6 hours. The information remains the same. The real intensity was not constant over the 6 hours, obviously. You cannot, therefore, obtain the real 1-hour rainfall depth for each hours from 6-hours rainfall depth but only an average value that assumes it constant in each hour. If you have the measured 1-hour rainfall depth data in meter and you calculate the intensity in m/s from that data the results will be different.&lt;/p&gt;&#xA;&lt;p&gt;I hope to have correctly understood your doubts and that this made things clearer.&lt;/p&gt;&#xA;" OwnerUserId="20722" LastActivityDate="2020-07-09T15:12:50.907" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19923" PostTypeId="2" ParentId="19921" CreationDate="2020-07-10T10:39:53.887" Score="3" Body="&lt;p&gt;OK I did a &lt;a href=&quot;https://drive.google.com/file/d/1fkL-H4DzDITdvy6yygTZqsz8ROee1f10/view?usp=sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt; on mitigating climate change by enhanced weathering of rock on agricultural land for my masters (2014) it's not brilliant, but it does include some useful references if you want to research this further.&lt;/p&gt;&#xA;&lt;p&gt;I would imagine the main limiting factor in the Sahel region would be that the process needs to be wet. So you're possibly only talking about being able to add material to irrigated areas. There are also the limitations you've already discussed of getting the material on site. In terms of crop yield, I would suggest that it will only increase plant growth in areas which do not already have alkaline geology (and I have no idea what the geology looks like in the Sahel, I'm afraid) and adding too much to soils may well actually &lt;em&gt;decrease&lt;/em&gt; site fertility without the addition of something else (manure is the traditional amendment)&lt;/p&gt;&#xA;&lt;p&gt;As far as I'm aware, enhanced weathering is perfectly technologically feasible, but it does have a limited application - due to the sheer quantity of it we'd need.&lt;/p&gt;&#xA;&lt;p&gt;Hope this helps.&lt;/p&gt;&#xA;" OwnerUserId="18621" LastActivityDate="2020-07-10T10:39:53.887" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19924" PostTypeId="2" ParentId="19801" CreationDate="2020-07-10T15:50:04.507" Score="0" Body="&lt;p&gt;I would rewrite your equation in a more natural order, at least to me:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{DT}{Dt} = \frac{\partial T}{\partial t} + \mathbf{U} \cdot \nabla T $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The term &lt;span class=&quot;math-container&quot;&gt;$\frac{DT}{Dt} $&lt;/span&gt; is the total derivative of &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; with respect to time, i.e. how temperature changes (in one particular place on Earth) with time passing, which can have different reasons. The term &lt;span class=&quot;math-container&quot;&gt;$\mathbf{U} \cdot \nabla T$&lt;/span&gt;, as you point out, is the advective term. It expresses that winds can bring warmer or cooler air onto this place, making it cooler or warmer there, such as cold fronts.&lt;/p&gt;&#xA;&lt;p&gt;The term  &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial T}{\partial t} $&lt;/span&gt; expresses the &lt;span class=&quot;math-container&quot;&gt;$local$&lt;/span&gt; change of temperature with time. If no winds are blowing, temperature may change as well, for example due to insolation (cooler at night, warmer during the day), seasonality and so on.&lt;/p&gt;&#xA;&lt;p&gt;Therefore, the term &lt;span class=&quot;math-container&quot;&gt;$\frac{DT}{Dt}$&lt;/span&gt; on the left-hand side of the equation makes it maybe it more clear. It is not a component of the derivate, it is &lt;strong&gt;the total&lt;/strong&gt; derivative, decomposed in local and advective terms. So advection &lt;strong&gt;is&lt;/strong&gt; one of the components of &lt;span class=&quot;math-container&quot;&gt;$\frac{DT}{Dt}$&lt;/span&gt;.&lt;/p&gt;&#xA;" OwnerUserId="8396" LastActivityDate="2020-07-10T15:50:04.507" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19925" PostTypeId="1" CreationDate="2020-07-11T21:26:43.137" Score="1" ViewCount="264" Body="&lt;p&gt;During hot weather, it is uncommon for there to be rain without lightning and thunder if the weather is hot. I find that the general rule of thumb is that if it is raining while it is 70 degrees or higher, it is usually accompanied with lightning and thunder but still sometimes can happen at colder temperatures too like during the spring. However is it possible for there to be 85 to 90 degrees F without any lightning and thunder?&lt;/p&gt;&#xA;" OwnerUserId="17923" LastActivityDate="2020-07-11T21:26:43.137" Title="Rain during Hot Weather" Tags="|rain|thunderstorm|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19927" PostTypeId="1" CreationDate="2020-07-14T02:34:41.200" Score="1" ViewCount="125" Body="&lt;p&gt;I see from a news report that the all-time high temperature, anywhere on Earth, is 129 F. But temperatures within 10 degrees of that record are not rare, and temperatures within 20 degrees are pretty widespread. Why does there seem to be a ceiling on the high temperature, such that a lot of places approach that temperature and don't exceed it? A related question -- why isn't the high temperature much higher, such as, I don't know, 150 degrees?&lt;/p&gt;&#xA;&lt;p&gt;In contrast, the coldest temperature is -129 F, and few places ever get anywhere near that. Why is there such a disparity between high temperatures and low temperatures in that way?&lt;/p&gt;&#xA;&lt;p&gt;EDIT: By the way, I apologize for the US-centric temperature measurements. I hope I got the point across nonetheless.&lt;/p&gt;&#xA;" OwnerUserId="20735" LastActivityDate="2020-07-15T03:27:48.903" Title="Why are temperatures within a few degrees of the all-time high actually pretty common?" Tags="|meteorology|temperature|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19928" PostTypeId="1" AcceptedAnswerId="19929" CreationDate="2020-07-14T04:51:47.020" Score="3" ViewCount="69" Body="&lt;p&gt;I've noticed that in many &lt;a href=&quot;https://doi.org/10.1029/2018JD030092&quot; rel=&quot;nofollow noreferrer&quot;&gt;papers&lt;/a&gt; it's common to assume the (daily or longer averaged)  vertically integrated radiative heating can be expressed &lt;span class=&quot;math-container&quot;&gt;$F_z(\text{TOA})-F_z(\text{SURF})$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$F_z$&lt;/span&gt; is the vertical component of radiative flux, and &lt;span class=&quot;math-container&quot;&gt;$\text{TOA}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\text{SURF}$&lt;/span&gt; denote the top of atmosphere and surface respectively, with &amp;quot;top of atmosphere&amp;quot; usually either taken as &lt;span class=&quot;math-container&quot;&gt;$z\to \infty$&lt;/span&gt;, or as the tropopause height, depending on the context.&lt;/p&gt;&#xA;&lt;p&gt;I assume this basically reflects the fact that if we express radiative heating &lt;span class=&quot;math-container&quot;&gt;$Q$&lt;/span&gt; as a flux divergence &lt;span class=&quot;math-container&quot;&gt;$Q=\nabla \cdot (F_x,F_y,F_z)$&lt;/span&gt;, vertical integration gives&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{align}&#xA;\int_\text{SURF}^\text{TOA} Q \,dz &amp;amp;= \int_\text{SURF}^\text{TOA} \nabla_H \cdot (F_x, F_y) \,dz + \int_\text{SURF}^\text{TOA} \frac{\partial F_z}{\partial z} \,dz \\ &#xA;&amp;amp;= \int_\text{SURF}^\text{TOA} \nabla_H \cdot (F_x, F_y) \,dz + F_z(\text{TOA})-F_z(\text{SURF}).&#xA;\end{align}&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;It seems natural to assume the &lt;span class=&quot;math-container&quot;&gt;$\int_\text{SURF}^\text{TOA} \nabla_H \cdot (F_x, F_y) \,dz$&lt;/span&gt; term, which is the net horizontal flux divergence out of the column, will be small compared to the &lt;span class=&quot;math-container&quot;&gt;$F_z(\text{TOA})-F_z(\text{SURF})$&lt;/span&gt; term, but does anyone know &lt;em&gt;just how much smaller&lt;/em&gt;? What are some reasonable scale estimates for these terms? Are there situations in atmospheric science where net horizontal radiative flux divergence can't be neglected?&lt;/p&gt;&#xA;&lt;p&gt;For example, I'm imagining a column with a single spherical cloud in it, and the sun directly overhead, but no clouds in any other nearby columns. In such a situation, wouldn't there be a horizontal radiative flux divergence, i.e. a net horizontal radiative flux out of the column? Would this effect still have a negligible impact on net column heating, or does nothing like this occur in real atmospheres?&lt;/p&gt;&#xA;" OwnerUserId="4587" LastActivityDate="2020-07-14T15:05:41.073" Title="Can Horizontal Radiation Fluxes Contribute to Net Column Heating?" Tags="|atmospheric-radiation|energy-balance|radiation-balance|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19929" PostTypeId="2" ParentId="19928" CreationDate="2020-07-14T15:05:41.073" Score="1" Body="&lt;p&gt;Yes, there are horizontal radiation fluxes. &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JD094iD13p16277&quot; rel=&quot;nofollow noreferrer&quot;&gt;These can change the heating rate by 10-40 K hr&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt;.&lt;/a&gt; &lt;a href=&quot;https://journals.ametsoc.org/jas/article/62/8/2939/26087/The-Impact-of-Model-Resolution-on-Differences&quot; rel=&quot;nofollow noreferrer&quot;&gt;They also change depending on the extent of the atmosphere you may be considering&lt;/a&gt;. One can also imagine that they are a bit stronger during the sunrise and sunset, when the sun is not directly overhead and the beam has a larger horizontal path length.&lt;/p&gt;&#xA;&lt;p&gt;There is work, such as the &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0022407315002964&quot; rel=&quot;nofollow noreferrer&quot;&gt;Neighboring Column Approximation&lt;/a&gt; which tries to get around that. There's another paper, but I can't find it right now that also tries to resolve this issue.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-07-14T15:05:41.073" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19930" PostTypeId="1" CreationDate="2020-07-15T03:25:35.520" Score="4" ViewCount="1251" Body="&lt;p&gt;Milankovitch cycles consist of three orbital parameters: eccentricity, obliquity, and precession of equinoxes.&lt;/p&gt;&#xA;&lt;p&gt;According to Milutin Milankovitch, the most recent glacial period ended nearly 11,000 years ago, when combination of eccentricity, obliquity, and precession at that time strongly favored deglaciation in the northern high latitudes. Specifically, eccentricity, moving on cycles of 100,000 years, was slightly larger than it is today, and Earth was slightly elliptical than it is today. Obliquity, moving between 22.1 and 24.5 degrees, was nearly at its maximum 11,000 years ago. And precession was pointing at Vega.&lt;/p&gt;&#xA;&lt;p&gt;It then goes that this combination of orbital parameters enabled the northern hemisphere to experience its summer solstice at the perihelion, which gave the northern hemisphere the largest possible solar radiation on any summer solstice positions. And obliquity was at its maximum, significantly reducing the size of polar regions shielded from solar radiation between the spring and fall equinoxes in the northern hemisphere. So the northern high latitudes experienced a high volume of incoming solar radiation that allowed snow accumulation rate to fall below that of snow melting. Thus, the most recent glacial period started to end.&lt;/p&gt;&#xA;&lt;p&gt;But now, 11,000 years after the last glacial period, the combination of orbital parameters changed a lot. Eccentricity is near its lowest, making the total solar radiation on Earth at perihelion and aphelion closer than ever. Obliquity is midway between the maximum and the minimum, shielding a significant area of the polar regions from incoming summer sunlight. And precession is now pointing at the Polaris, the exact opposite of Vega. This combination allows the northern hemisphere to experience its summer solstice at the aphelion, and winter solstice at the perihelion, which significantly curtails the amount solar radiation in the northern hemisphere. The northern high latitudes now are shielded more from solar radiation between the spring and fall equinoxes. These new changes seem to make Earth go in the direction of another glacial period, because snow melting seems to be slowing in the northern high latitudes and snow accumulation quickening.&lt;/p&gt;&#xA;&lt;p&gt;Throughout geological history, Earth has seen far lengthier and more widespread glacials than interglacials. Indeed, interglacials are just short blips in the geological history. It thus seems reasonable to say we are entering another Ice Age according to Milankovitch cycles.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jmkpi.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jmkpi.jpg&quot; alt=&quot;Glacials and Interglacials in Earth's History&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Some of you may cite the current anthropogenic climate change as a rebuttal, but for the question's sake, just ignore it.&lt;/p&gt;&#xA;" OwnerUserId="20732" LastActivityDate="2021-05-18T08:57:20.257" Title="Are we entering a new Ice Age according to Milankovitch cycles?" Tags="|climate|earth-history|milankovitch-cycles|axial-obliquity|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19931" PostTypeId="2" ParentId="19927" CreationDate="2020-07-15T03:27:48.903" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;the coldest temperature is -129 F, and few places ever get anywhere near that.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is at high altitudes in Antarctica. There are very few places with weather stations (geographically) near there.&lt;/p&gt;&#xA;&lt;p&gt;There are more places with weather stations near the hottest places, so (because mathematical statistics theorem) there are more record max readings near the global max.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2020-07-15T03:27:48.903" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19933" PostTypeId="2" ParentId="19930" CreationDate="2020-07-15T10:31:49.907" Score="4" Body="&lt;p&gt;Orbital cycles doubtlessly play a role in the &lt;a href=&quot;https://climate.nasa.gov/news/2948/milankovitch-orbital-cycles-and-their-role-in-earths-climate/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Quaternary climate record&lt;/a&gt;, together with other effects like &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016GL071307&quot; rel=&quot;nofollow noreferrer&quot;&gt;ice sheet dynamics&lt;/a&gt;, but their effect is dwarfed by speed and amount of the current climate change. Even if we were in for a new glaciation from orbital parameters alone (which is not the case), there'd be &lt;a href=&quot;https://climate.nasa.gov/blog/2949/why-milankovitch-orbital-cycles-cant-explain-earths-current-warming/&quot; rel=&quot;nofollow noreferrer&quot;&gt;no use counting on it&lt;/a&gt; because they work on longer timescales, reaching from 10s of thousands to &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4611626/&quot; rel=&quot;nofollow noreferrer&quot;&gt;millions of years&lt;/a&gt;. An answer can, of course, be fleshed out endlessly simply because of the complexity of the processes at work and the increasing knowledge base. Isolating one effect, here M. cycles, likely leeds to misconceptions.&lt;/p&gt;&#xA;&lt;p&gt;Tl; dr, and to answer the question:&lt;/p&gt;&#xA;&lt;p&gt;No, we are not due for a new glaciation (not a new &amp;quot;Ice Age&amp;quot;, we are in an ice age) from orbital forcing alone.&lt;/p&gt;&#xA;&lt;p&gt;Citing &lt;a href=&quot;https://www.nature.com/articles/nature16494&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ganopolski et. al. Critical insolation–CO2 relation for diagnosing past and future glacial inception&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Additionally, our analysis suggests that even in the absence of human perturbations no substantial build-up of ice sheets would occur within the next several thousand years and that the current interglacial would probably last for another 50,000 years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-07-15T20:32:52.647" LastActivityDate="2020-07-15T20:32:52.647" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19934" PostTypeId="2" ParentId="16172" CreationDate="2020-07-15T16:42:21.050" Score="2" Body="&lt;p&gt;I think you might be getting confused. There is relative humidity. If you put in different values, you will get different results. For instance, if you replace the variable names of one of your functions (say replace Min with Max), you will have the same exact function.&lt;/p&gt;&#xA;&lt;p&gt;Relative humidity is a ratio of the amount of water vapor in the air to the amount of water vapor that could be in the air (saturation vapor pressure &lt;span class=&quot;math-container&quot;&gt;$e_s$&lt;/span&gt;): &lt;span class=&quot;math-container&quot;&gt;$$RH=100\%\times\frac{e}{e_s}$$&lt;/span&gt; Since the saturation vapor pressure decreases with increasing temperature (&lt;a href=&quot;https://en.wikipedia.org/wiki/Clausius%E2%80%93Clapeyron_relation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Clausius Clapeyeron equation&lt;/a&gt;):&lt;span class=&quot;math-container&quot;&gt;$$e_s=611 \exp\left(\frac{L_v}{R_v}\left[\frac{1}{273.15}-\frac{1}{T}\right]\right)$$&lt;/span&gt; it is conceivable, and also not uncommon, for the maximum relative humidity to occur when the temperature and specific humidity is at a minimum.&lt;/p&gt;&#xA;&lt;p&gt;So can the minimum relative humidity be greater than the maximum relative humidity? By definition of minimum and maximum, no. But the times that the minimum and maximum relative humidity occur are often counter-intuitive.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-07-15T16:42:21.050" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19935" PostTypeId="2" ParentId="19930" CreationDate="2020-07-15T16:42:43.500" Score="8" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;It thus seems reasonable to say we are entering another Ice Age according to Milankovitch cycles.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Some of the Milankovitch conditions would appear to make the Earth ripe for a new glacial epoch starting now, or perhaps a few hundred years ago. In particular, aphelion occurs in early July, and obliquity is low. Both of these make for mild northern hemisphere summers, a key condition needed for snowfall from the previous seasons to linger into fall.&lt;/p&gt;&#xA;&lt;p&gt;But one other key Milankovitch condition needed to make snowfall linger, orbital eccentricity, argues against a new glacial epoch starting now. The low (and decreasing) eccentricity makes the current dip in summertime insolation at high northern latitudes too small of a dip to trigger the onset of an glacial epoch. Look at the graph you posted in your question. Glacial epochs start when summertime insolation at high northern latitudes drops to very low values. The current local minimum is not low enough to enable widespread accumulation of snow and ice over the summer.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Some of you may cite the current anthropogenic climate change as a rebuttal, but for the question's sake, just ignore it.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Even without anthropogenic help, the current interglacial is likely to last for 50,000 years [Berger and Loutre]. With anthropogenic help, the current interglacial may even last indefinitely [Steffen].&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Throughout geological history, Earth has seen far lengthier and more widespread glacials than interglacials. Indeed, interglacials are just short blips in the geological history.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;That is true only for last 2.58 million years, possibly the last 34 million years. The Earth has been ice-free for most of the last 550 million years. Ice ages (periods during which ice can form, intermittently, are just short blips.&lt;/p&gt;&#xA;&lt;br&gt;&#xA;References:&#xA;&lt;br&gt;Berger, André, and Marie-France Loutre. &quot;An exceptionally long interglacial ahead?.&quot; Science 297.5585 (2002): 1287-1288.&#xA;&lt;br&gt;&#xA;&lt;br&gt;&#xA;Steffen, Will, et al. &quot;Trajectories of the Earth System in the Anthropocene.&quot; Proceedings of the National Academy of Sciences 115.33 (2018): 8252-8259.&#xA;" OwnerUserId="239" LastActivityDate="2020-07-15T16:42:43.500" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19936" PostTypeId="1" AcceptedAnswerId="19938" CreationDate="2020-07-15T19:30:14.433" Score="1" ViewCount="70" Body="&lt;p&gt;&lt;strong&gt;How far downwind of a covid-19 emitter has a 1000-fold reduction in PPM?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Assuming that covid-19 (0.12μm diameter) particles have the aerodynamic properties of a gas:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Particles &amp;lt; 20 μm behave same as gas – Low settling velocity&#xA;&lt;a href=&quot;http://home.engineering.iastate.edu/%7Eleeuwen/CE%20524/Presentations/Dispersion_Handout.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://home.engineering.iastate.edu/~leeuwen/CE%20524/Presentations/Dispersion_Handout.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;How far would someone have to be downwind of a covid-19 particle emitter for an at least 1000-fold reduction in PPM?&lt;/p&gt;&#xA;" OwnerUserId="17970" LastActivityDate="2020-07-15T21:39:01.810" Title="How far downwind of a covid-19 emitter has a 1000-fold reduction in PPM?" Tags="|atmosphere|turbulence|aerosol|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19937" PostTypeId="2" ParentId="19921" CreationDate="2020-07-15T19:34:49.930" Score="1" Body="&lt;p&gt;Note that the sahel is a lost cause for the rainfall/CO2 absorption side of the equation. Heat tends to mineralize soil and reduce its organic content, so the sahel may be too hot. For fertiliser, rock dust is economically significant.&lt;/p&gt;&#xA;&lt;p&gt;The program should be quantified:&lt;/p&gt;&#xA;&lt;p&gt;Available budget for the project.&lt;/p&gt;&#xA;&lt;p&gt;KG mass of rock:&lt;/p&gt;&#xA;&lt;p&gt;Quarry cost. Transport cost. Truck+Fuel cost. Crushing machine cost. Energy cost. Dissemination labour organization. Training schemes to instruct dust dissemination. Dissemination machines. Rain window period. Maximium rock load for a given precipitation rate, i.e. 10g/m2 per 1cm of rain.&lt;/p&gt;&#xA;&lt;p&gt;Using planes to lift 100 tonnes of dust per day may be cheaper than using trucks (a 747 can lift 112 metric tonnes).&lt;/p&gt;&#xA;" OwnerUserId="3315" LastActivityDate="2020-07-15T19:34:49.930" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19938" PostTypeId="2" ParentId="19936" CreationDate="2020-07-15T21:39:01.810" Score="3" Body="&lt;p&gt;As I said in my comment, viruses aren't my area (concerning units). But the answer is actually unitless. The exact answer you seek is dependent on a couple of different variables:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The speed of the exhalation (cough or breathing)+speed of wind&lt;/li&gt;&#xA;&lt;li&gt;The atmospheric stability&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Of course, the viral load of the exhalation is also important, but since you're asking for a ratio, I won't list that.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;http://courses.washington.edu/cewa567/Plumes.PDF&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gaussian Plume model&lt;/a&gt; can be used to describe pollutants. The Gaussian Plume model is: &lt;span class=&quot;math-container&quot;&gt;$$\frac{C}{Q}=\frac{1}{2\pi U \sigma_y \sigma_z}\exp\left(-\frac{1}{2}\left[\frac{y}{\sigma_y}\right]^2-\frac{1}{2}\left[\frac{z-H}{\sigma_z}\right]^2\right)$$&lt;/span&gt;,&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; is the concentration, &lt;span class=&quot;math-container&quot;&gt;$Q$&lt;/span&gt; is the emission rate, &lt;span class=&quot;math-container&quot;&gt;$U$&lt;/span&gt; is the wind speed (or worst case-scenario is cough speed), &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; is the downwind distance, &lt;span class=&quot;math-container&quot;&gt;$z$&lt;/span&gt; is the distance from the ground, and &lt;span class=&quot;math-container&quot;&gt;$\sigma_x, \sigma_z$&lt;/span&gt; are the horizontal and vertical diffusion constants.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\sigma_y, \sigma_z$&lt;/span&gt; are functions of stability and wind speed. The actual formulas are... iffy. Theoretically they can be described as &lt;span class=&quot;math-container&quot;&gt;$$\sigma_{y,z}=\sqrt{\frac{2K_{y,z}x}{U}}$$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$K$&lt;/span&gt; is the eddy viscosity. &lt;a href=&quot;http://courses.washington.edu/cee490/DISPCOEF4WP.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;There are empirical formulas based on stability classifications too.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Lets assume that the receiver is directly downwind and at the same height (z=H and y=0). Therefore the equation collapses to: &lt;span class=&quot;math-container&quot;&gt;$$\frac{C}{Q}=\frac{1}{2\pi U \sigma_y \sigma_z}$$&lt;/span&gt;. Since the distance downwind is expressed only by &lt;span class=&quot;math-container&quot;&gt;$\sigma_{y,z}$&lt;/span&gt;, then to answer your question, we need to isolate &lt;span class=&quot;math-container&quot;&gt;$\sigma_{y,z}$&lt;/span&gt;. &lt;span class=&quot;math-container&quot;&gt;$$\sigma_y \sigma_z=\frac{1000}{2\pi U}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Let's just say, for the sake of argument, consider two different scenarios:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Empirical &lt;span class=&quot;math-container&quot;&gt;$\sigma_{y,z}$&lt;/span&gt; (refer to &lt;a href=&quot;http://courses.washington.edu/cee490/DISPCOEF4WP.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; for values of constants)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$(ax^b)\times (cx^d+f)=acx^{b+d}+afx^b=\frac{1000}{2\pi U}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;And this is complicated to solve. So I'll leave solving for &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; as an exercise to the reader.&lt;/p&gt;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;Constant &lt;span class=&quot;math-container&quot;&gt;$K_{y,z}$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\sqrt{\frac{2K_{z}x}{U}}\sqrt{\frac{2K_{y}x}{U}}=\frac{1000}{2\pi U}$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{4K_{z}K_{y}x^2}{U^2}=\left(\frac{1000}{2\pi U}\right)^2=\frac{10^6}{4\pi^2U^2}$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$x=\sqrt{\frac{10^6 K_{z}K_{y}}{16\pi^2}}$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$x=\frac{10^3}{4\pi}\sqrt{K_{z}K_{y}}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;If we assume that &lt;span class=&quot;math-container&quot;&gt;$K_z=K_y=K$&lt;/span&gt;, then the equation simplifies further. &lt;span class=&quot;math-container&quot;&gt;$$x=\frac{K10^3}{4\pi}$$&lt;/span&gt;&#xA;There are many ways on how to calculate &lt;span class=&quot;math-container&quot;&gt;$K$&lt;/span&gt;. One simple formula for &lt;span class=&quot;math-container&quot;&gt;$K$&lt;/span&gt; can be used if mixing length theory is invoked&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$K=\frac{ku_*z}{\phi(\frac{z}{L})}$$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$k$&lt;/span&gt; is the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Von_k%C3%A1rm%C3%A1n%27s_constant&quot; rel=&quot;nofollow noreferrer&quot;&gt;von-Karman constant&lt;/a&gt;, &lt;span class=&quot;math-container&quot;&gt;$u_*$&lt;/span&gt; is the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Friction_velocity&quot; rel=&quot;nofollow noreferrer&quot;&gt;friction velocity&lt;/a&gt;, &lt;span class=&quot;math-container&quot;&gt;$\phi_M(\frac{z}{L})$&lt;/span&gt; is the &lt;a href=&quot;https://gibbs.science/efd/handouts/dyer_1974.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Businger-Dyer function&lt;/a&gt; for momentum, and &lt;span class=&quot;math-container&quot;&gt;$L$&lt;/span&gt; is the Monin-Obukhov length. If we assume neutral atmospheric stability,&lt;span class=&quot;math-container&quot;&gt;$\phi_M(\frac{z}{L})=1$&lt;/span&gt; and the resultant equation can be written as:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$x=\frac{ku_*z10^3}{4\pi}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;More assumptions! Let's assume z=1.5 m and &lt;span class=&quot;math-container&quot;&gt;$u_*=1.11$&lt;/span&gt; m s&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt; &lt;a href=&quot;https://en.wikipedia.org/wiki/Log_wind_profile&quot; rel=&quot;nofollow noreferrer&quot;&gt;(corresponds to a 5 kt wind speed at 10 m with a roughness length of 0.1 m under neutral stability)&lt;/a&gt;. Plugging those numbers in gets&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$x=35$&lt;/span&gt; m&lt;/p&gt;&#xA;&lt;p&gt;Of course, there were a LOT of assumptions to get to this point. But this is what I have to offer.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-07-15T21:39:01.810" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="19939" PostTypeId="1" AcceptedAnswerId="19940" CreationDate="2020-07-16T03:18:06.720" Score="6" ViewCount="1490" Body="&lt;p&gt;Last night was pretty chilly here in South East Queensland, Australia.&lt;/p&gt;&#xA;&lt;p&gt;We woke this morning to condensation on the bedroom windows but noticed something curious.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GiEXf.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GiEXf.jpg&quot; alt=&quot;Condensation on window&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where a small branch was touching the window there was no condensation.  What caused this?&lt;/p&gt;&#xA;" OwnerUserId="20742" LastActivityDate="2020-07-19T06:30:23.430" Title="Why did a branch against a window prevent condensation?" Tags="|meteorology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19940" PostTypeId="2" ParentId="19939" CreationDate="2020-07-16T04:28:19.857" Score="9" Body="&lt;p&gt;The branch block outgoing infrared radiation and reflect some of it back to the window this will keep the temperature slightly above the condensation point.&lt;/p&gt;&#xA;&lt;p&gt;Infrared radiation is the same as heat radiation.&lt;/p&gt;&#xA;&lt;p&gt;Most objects will block and reflect infrared radiation and this is why dew does not form under a tree or under different types of roofs and objects partially covering the ground.&lt;/p&gt;&#xA;&lt;p&gt;The CO&lt;sub&gt;2&lt;/sub&gt; in our atmosphere has a similar effect,absorbing and re emitting the infrared radiation keeping earth warm at night,had it not been for the different greenhouse gasses the temperature changes during the day night cycles had been a lot larger.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="2470" LastEditDate="2020-07-16T05:16:45.133" LastActivityDate="2020-07-16T05:16:45.133" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19942" PostTypeId="1" CreationDate="2020-07-17T07:20:12.347" Score="1" ViewCount="36" Body="&lt;p&gt;I've been reading papers on convective self-aggregation, such as &lt;a href=&quot;https://doi.org/10.1175/JAS3614.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bretherton (2005)&lt;/a&gt; and &lt;a href=&quot;https://doi.org/10.1175/1520-0469(2003)060%3C0607:CRMOTA%3E2.0.CO;2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Khairoutdinov (2003)&lt;/a&gt;, and it's not clear to me why (or whether) self-aggregation depends on the model being initialised from radiative convective equilibrium (RCE). Are there any papers that show self-aggregation can occur in homogenous, no-shear, non-RCE conditions?&lt;/p&gt;&#xA;&lt;p&gt;It's possible I'm missing the point of these studies. It may be the idea is more that it's &lt;em&gt;surprising&lt;/em&gt; aggregation occurs &lt;em&gt;despite&lt;/em&gt; RCE, because RCE is supposed to represent a balanced equilibrium state. Would this mean aggregation disrupts RCE, and that RCE is actually an &amp;quot;unstable&amp;quot; equilibrium?&lt;/p&gt;&#xA;" OwnerUserId="4587" LastEditorUserId="4587" LastEditDate="2020-07-24T07:12:50.640" LastActivityDate="2020-07-24T07:12:50.640" Title="Do Self-Aggregation Simulations Depend Crucially on Radiative-Convective Equilibrium (RCE) Initial Conditions?" Tags="|climate|convection|radiative-transfer|radiation-balance|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19943" PostTypeId="1" CreationDate="2020-07-18T04:28:01.373" Score="0" ViewCount="209" Body="&lt;p&gt;Estimates &lt;a href=&quot;https://www.space.com/37627-total-solar-eclipse-earth-moon-alignment-future.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;put the last solar eclipse at 600 million years&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The question then becomes how much time is left on Earth?  Stephen Hawking believes we have less then a &lt;a href=&quot;https://qz.com/1229008/stephen-hawking-warned-that-we-have-100-years-left-on-earth-but-he-was-an-optimist-about-humanity/&quot; rel=&quot;nofollow noreferrer&quot;&gt;100 years left&lt;/a&gt; on Earth but that seems like an underestimate.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In &lt;a href=&quot;https://en.wikipedia.org/wiki/Future_of_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;about 600 million years from now&lt;/a&gt;, the level of carbon dioxide will fall below the level needed to sustain C3 carbon fixation photosynthesis used by trees.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="18108" LastActivityDate="2020-07-24T16:52:23.033" Title="Will life still be sustainable on earth when solar eclipses stop?" Tags="|climate-change|climate-models|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="19944" PostTypeId="2" ParentId="19943" CreationDate="2020-07-18T13:13:20.923" Score="4" Body="&lt;p&gt;Stephen Hawking believed so because of technolgical reasons unrelated to geoscience, that technology and engineering will end the human existence.&lt;/p&gt;&#xA;&lt;p&gt;Yes, if all goes well and only looking at the limiting elements &amp;quot;solar evolution&amp;quot; and &amp;quot;plate tectonics&amp;quot; life will still be there in ~600 million years. Though complexity may be drastically reduced and it will probably be limited to extremophiles in a few niches. The time of life on earth will eventually run out in the far future, but the timing is not of specifical scientific interest. Thoughts range from 500My to 1.5By, afaik.&lt;/p&gt;&#xA;&lt;p&gt;The outline in the wikipedia article shows the principles, though I'd be careful taking such details as CO2 concentration in 600 million years too serious. Anyway, over these timescales, the sun will get hotter and plate tectonics (a transient thing anyway) will slow down and stop, interrupting regenerative and climate regulating cycles.&lt;/p&gt;&#xA;&lt;p&gt;Statements concerning the future are, of course, highly speculative and because of that I leave it be to search for geo-scientifically relevant links on the matter. A lot of things with fundamental influence can happen much earlier (like in the coming decades).&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-07-19T12:57:35.840" LastActivityDate="2020-07-19T12:57:35.840" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19945" PostTypeId="1" CreationDate="2020-07-18T18:01:32.693" Score="1" ViewCount="157" Body="&lt;p&gt;I will be starting a Master's program in data science soon and my eventual hope/goal is to do climate-related data science work. I did an independent study for one semester in college on the mathematics of climate and it inspired me to want to learn more and possibly pursue climate research as a career path. The two main textbooks I used for that class were &lt;a href=&quot;https://epubs.siam.org/doi/book/10.1137/1.9781611972610?mobileUi=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mathematics of Climate&lt;/a&gt; (Hans Kaper and Hans Engler) and &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/0125586914&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atmosphere, Ocean, and Climate Dynamics&lt;/a&gt; (John Marshall and R. Alan Plumb). My undergrad major was applied math, so my knowledge is limited mainly to content in those two books. In hopes of obtaining more background knowledge on environmental and climate sciences, I'm wondering if anyone can recommend textbooks that I could self-study before I start the program, so that I could potentially do a climate-related final project. I'm hoping to gain as wide a range of knowledge as I can during the next couple of months, so I welcome suggestions on anything (whether textbooks or other resources) that might be useful or just plain interesting! I will also mention that any books that include data assimilation would be superb. Thank you!&lt;/p&gt;&#xA;" OwnerUserId="16748" LastEditorUserId="18081" LastEditDate="2022-08-04T09:09:06.100" LastActivityDate="2022-08-04T09:09:06.100" Title="Seeking climate and related sciences textbook recommendations" Tags="|climate|climate-models|data-analysis|reference-request|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19946" PostTypeId="2" ParentId="19945" CreationDate="2020-07-19T01:34:11.783" Score="2" Body="&lt;p&gt;There are loads of books. I will refer you to one of &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13696/can-anyone-recommend-a-good-college-level-meteorology-textbook/13698#13698&quot;&gt;my previous answers&lt;/a&gt; which can apply to the meteorological aspects of climate. An additional classic for climate is &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/0883187124&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Physics of Climate by Peixoto and Oort&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-07-19T01:34:11.783" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19947" PostTypeId="2" ParentId="19939" CreationDate="2020-07-19T06:30:23.430" Score="3" Body="&lt;p&gt;The glass will be receiving heat from the inside and transferring it outside via several mechanisms, both radiant heat in the infrared and conduction/convection by its contact with the warm indoor air and cold outdoor air.&lt;/p&gt;&#xA;&lt;p&gt;It's difficult to say for sure which loss mechanism is most important in this case, but &lt;a href=&quot;https://earthscience.stackexchange.com/a/19940/6031&quot;&gt;the other answer&lt;/a&gt; only mentions radiation and as suggested in comments there it's hard to believe that the reduced motion of the air around the branch isn't contributing significantly.&lt;/p&gt;&#xA;&lt;p&gt;It's also important to point out that lateral heat flow within the glass from the warmer to the colder areas of the glass is also important. If the window were made of the fictitious &amp;quot;transparent aluminum&amp;quot; with high thermal conductivity, it would be a uniform temperature. It's only because the conductivity of the glass is so low that it can support a thermal gradient.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2020-07-19T06:30:23.430" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19948" PostTypeId="1" AcceptedAnswerId="19949" CreationDate="2020-07-19T13:16:25.650" Score="1" ViewCount="32" Body="&lt;p&gt;I am a very beginning in planting three.&lt;/p&gt;&#xA;&lt;p&gt;I sent a ground sample for analysis and one of the results is the pH value of&lt;/p&gt;&#xA;&lt;p&gt;pH &lt;strong&gt;6.2&lt;/strong&gt; in &lt;code&gt;water&lt;/code&gt; solution and&lt;br /&gt;&#xA;pH &lt;strong&gt;4.75&lt;/strong&gt; in &lt;code&gt;KCl&lt;/code&gt; solution.&lt;/p&gt;&#xA;&lt;p&gt;I am planning to seed walnut tree which likes most alkaline ground rather than acidic.&lt;/p&gt;&#xA;&lt;p&gt;One of the solutions for fixing Ph value is to put limestone in the ground but this needs at least 2 years to finish part of the process and also can affect microelements in the ground like Iron or Boron.&lt;/p&gt;&#xA;&lt;p&gt;Assuming that current pH value is ok to start with planting&lt;br /&gt;&#xA;I would like to ask if there is some plant that can make ground alkaline and also Walnut friendly.&lt;/p&gt;&#xA;&lt;p&gt;Or in other words, is there a combination of plants with Walnut that can help each other to use the best from the ground without artificial ground fixing?&lt;/p&gt;&#xA;" OwnerUserId="20755" LastActivityDate="2020-07-19T16:22:55.233" Title="Fix pH Value ongoing with right plant" Tags="|agriculture|plant|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19949" PostTypeId="2" ParentId="19948" CreationDate="2020-07-19T16:22:55.233" Score="1" Body="&lt;p&gt;A pH of 6.2 is pretty acidic for soil . A more obvious method to lower acid would be limestone as gravel. And for a fast start ,add lime powder, available at any agriculture supply. Rototilling would be good ,but just sprinkling on the surface would be some help.  You can measure soil pH yourself easily. Put a soil sample in distilled water and shake in a sealed container ( to avoid CO 2 from the atmosphere ) .Then get pH indicator solution from a pet shop ( bromthymol blue ?) and test the water after the soil settles. Aquarium water is routinely tested with this indicator.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2020-07-19T16:22:55.233" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19951" PostTypeId="1" CreationDate="2020-07-20T00:25:57.307" Score="1" ViewCount="159" Body="&lt;p&gt;I know how to compute an n-vector given the latitude and longitude of a location. I want to compute the ECEF (Earth-centered, Earth-fixed) vector of two positions so that I can subtract those vectors to obtain a vector between the two positions (I know somewhere out there there's a formula for finding this more directly, however for my uses I need to calculate it as a difference of two ECEF vectors). How is this done?&lt;/p&gt;&#xA;" OwnerUserId="20759" LastActivityDate="2020-07-20T00:25:57.307" Title="How does one compute an ECEF vector?" Tags="|mathematics|geodesy|geometry|" AnswerCount="0" CommentCount="1" ClosedDate="2020-07-21T06:32:17.507" ContentLicense="CC BY-SA 4.0" />
  <row Id="19952" PostTypeId="1" CreationDate="2020-05-27T05:41:16.510" Score="1" ViewCount="209" Body="&lt;p&gt;I have some data from a radar to process in order to find the moments and in turn the wind speeds. I have no prior knowledge in signal processing so it's giving me a hard time to estimate the noise level from this spectrum.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;A sample power spectra for a range bin (height level) is depicted in the following image:&lt;br&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Dpn2L.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Dpn2L.png&quot; alt=&quot;enter image description here&quot;&gt;&lt;/a&gt;  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;I have already done windowing (another question might be needed whether I did it correctly or not) using a hamming window (by the scipy.signal.hamming function) and FFT is applied (using scipy.fft.fft function). Now I want to estimate the noise level using the &lt;a href=&quot;https://journals.ametsoc.org/doi/abs/10.1175/1520-0450%281974%29013%3C0808%3AODOTNL%3E2.0.CO%3B2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hildebrand &amp;amp; Sekhon&lt;/a&gt; method, and this is where I have got stuck.&#xA;Understanding it without some backgroud in signal processesing has proven to be quite difficult for me to implement the noise level estimation.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Could anybody explain how can I estimate the noise level in this spectrum using the Hildebrand &amp;amp; Sekhon method.  &lt;/p&gt;&#xA;&#xA;&lt;p&gt;Notes:&lt;br&gt;&#xA;There's 1024 NFFT points in the spectrum.&lt;/p&gt;&#xA;" OwnerUserId="9633" OwnerDisplayName="RogUE" LastEditorUserId="9633" LastEditDate="2020-07-22T05:21:28.113" LastActivityDate="2020-07-22T05:21:28.113" Title="Noise level estimation using Hildebrand &amp; Sekhon method" Tags="|meteorology|python|radar|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19954" PostTypeId="2" ParentId="19921" CreationDate="2020-07-21T08:26:37.120" Score="-1" Body="&lt;p&gt;More information on ERW here:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/s41477-018-0108-y.epdf?author_access_token=w1xYBFb3g3BwKnjkBD1cJtRgN0jAjWel9jnR3ZoTv0NSaZpth7Zz94N6_lHXNgths4xErTsML30mZS8Ql0FCuzY9k6ePi5nMsoEvmCXoU5g65l-c0C09tp3iWQMGMdfvbuwlRhm5_snv9tqy8Kc6ig%3D%3D&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/s41477-018-0108-y.epdf?author_access_token=w1xYBFb3g3BwKnjkBD1cJtRgN0jAjWel9jnR3ZoTv0NSaZpth7Zz94N6_lHXNgths4xErTsML30mZS8Ql0FCuzY9k6ePi5nMsoEvmCXoU5g65l-c0C09tp3iWQMGMdfvbuwlRhm5_snv9tqy8Kc6ig%3D%3D&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/s41477-018-0108-y.epdf?author_access_token=w1xYBFb3g3BwKnjkBD1cJtRgN0jAjWel9jnR3ZoTv0NSaZpth7Zz94N6_lHXNgths4xErTsML30mZS8Ql0FCuzY9k6ePi5nMsoEvmCXoU5g65l-c0C09tp3iWQMGMdfvbuwlRhm5_snv9tqy8Kc6ig%3D%3D&quot; rel=&quot;nofollow noreferrer&quot;&gt;Farming with crops and rocks to address global climate, food and soil security&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Hot climates are good for ERW -- the kinetics of weathering are temperature dependent. But as noted above you need water too.&lt;/p&gt;&#xA;" OwnerUserId="20767" LastEditorUserId="2470" LastEditDate="2020-07-21T09:30:42.327" LastActivityDate="2020-07-21T09:30:42.327" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19955" PostTypeId="1" CreationDate="2020-07-21T08:49:27.510" Score="4" ViewCount="107" Body="&lt;p&gt;The law describes several modes of lawn care like&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;type        max height, cm     cut height, cm   cuts per season      watering per season&#xA;parterre    5                  2 ~ 4            15 ~ 18              30&#xA;usual       10                 3 ~ 5            10 ~ 14              16&#xA;meadow      20                 3 ~ 5             2 ~ 5                0&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Climate in south-eastern Ukraine is +30C all the summer, almost no rains.&lt;/p&gt;&#xA;&lt;p&gt;Housing maintenance organizations usually have no any means to water the lawns, no money, no equipment for watering at all.&lt;/p&gt;&#xA;&lt;p&gt;Last 50 years most lawns were kept in meadow mode, that means that they were cut about twice a year without any watering.&#xA;The grass was very healthy, high and very diverse.&lt;/p&gt;&#xA;&lt;p&gt;About 3 years ago all urban areas were switched to the &amp;quot;usual&amp;quot; mode ( tick and ragweed control )&#xA;In fact that means that the lawns are cut to zero several times per season without any watering.&lt;/p&gt;&#xA;&lt;p&gt;As a result many lawns are yellow and dead for a long time and I see the gradual turf degradation.&lt;/p&gt;&#xA;&lt;p&gt;You can see it at two photos made in the almost the same date ( end of April, start of March ) with three years interval:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EG0rt.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EG0rt.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/asO6F.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/asO6F.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Also we have the mass death of the birches in the areas where the grass is regularly cut under them.&lt;/p&gt;&#xA;&lt;p&gt;The officials say that they just follow the instructions to fight tick and ragweed and the grass will regrow later when we will have more rain.&lt;/p&gt;&#xA;&lt;p&gt;I want to ask you to give your opinion about my understanding of the situation.&lt;/p&gt;&#xA;&lt;p&gt;I described my understanding in several theses below.&#xA;Please write me where I am right or wrong.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The surface of the grass is the catalyst of the dew.&lt;/li&gt;&#xA;&lt;li&gt;The higher the grass the more dew it will produce&lt;/li&gt;&#xA;&lt;li&gt;The dew evaporates during the day decreasing the temperature and increasing the humidity&lt;/li&gt;&#xA;&lt;li&gt;The dew is daily precipitation that is important for all plants including the trees&lt;/li&gt;&#xA;&lt;li&gt;The death of the birches could be caused by the absence of the high grass and the absence of the dew.&lt;/li&gt;&#xA;&lt;li&gt;The turf degradation will continue if the grass is cut to zero several times per season without any watering.&lt;/li&gt;&#xA;&lt;li&gt;The turf degradation will cause the desertification in several years and eventually the death of most trees because level of evaporation will be higher and the amount of the dew will be zero.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;( Also I will be very obliged if somebody could help me to contact the expert in the area of overgrazing and desertification.)&lt;/p&gt;&#xA;" OwnerUserId="20766" LastActivityDate="2020-07-21T08:49:27.510" Title="Can the frequent mowing without watering cause the total desertification in arid climate?" Tags="|ecology|desertification|" AnswerCount="0" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="19956" PostTypeId="2" ParentId="8446" CreationDate="2020-07-21T10:04:10.550" Score="1" Body="&lt;p&gt;I would  say, that given the same temperature humidity index and wind. It would be that person's perception. Un less you are out on a boat, or under a tree or surrounded by buildings and such. Other that that, I say we all come back here with some science.&lt;/p&gt;&#xA;" OwnerUserId="17367" LastActivityDate="2020-07-21T10:04:10.550" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19963" PostTypeId="1" CreationDate="2020-07-22T12:41:16.567" Score="-2" ViewCount="120" Body="&lt;p&gt;In my studies, Ive dropped a limestone or porous stone into water, with salt and sugar.&#xA;The results where an impressive light show of color flashes.&#xA;With the Earths natural release of gas, these colors of gas would rise up causing a dome shape and the pressure caused by the moisture hold it in one spot till it evaporates.&#xA;The sun beams enhancing the show of color.&#xA;Perhaps the reason Israel only shows 4 parts of the colors and not all 7.&#xA;Depending on Location, surface material.&#xA;-Just sharing a new way to look at Rainbows.&lt;/p&gt;&#xA;" OwnerDisplayName="user20769" LastEditorDisplayName="user20769" LastEditDate="2020-07-22T12:54:43.860" LastActivityDate="2020-07-22T13:23:33.163" Title="Are rainbows a reaction from earths natural release of gas after a rain?" Tags="|meteorology|weather-forecasting|carbon-cycle|" AnswerCount="1" CommentCount="0" ClosedDate="2020-07-26T20:06:20.003" ContentLicense="CC BY-SA 4.0" />
  <row Id="19964" PostTypeId="2" ParentId="19963" CreationDate="2020-07-22T13:23:33.163" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Rainbow&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rainbows&lt;/a&gt; are the result of water droplets in the atmosphere reflecting, refracting and dispersing light resulting in a spectrum of light in an arched shape in the sky.&lt;/p&gt;&#xA;&lt;p&gt;The water droplets in the atmosphere act the same way prisms do when they split white light into its component colors, hence the spectrum of light.&lt;/p&gt;&#xA;&lt;p&gt;The fact that the phenomenon is called a rainbow is due to rainbows generally appearing after certain rainfall events, when the atmosphere contains water droplets.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-07-22T13:23:33.163" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19967" PostTypeId="2" ParentId="8523" CreationDate="2020-07-23T18:08:28.163" Score="1" Body="&lt;p&gt;I'm from a place that &lt;em&gt;never&lt;/em&gt; has earthquakes and just about two years ago, I moved to San Jose, Costa Rica which experiences minor earthquakes daily &lt;a href=&quot;https://www.volcanodiscovery.com/earthquakes/costarica.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;. Since I've moved, I've experienced strong episodes of vertigo due to even the minor earthquakes.&lt;/p&gt;&#xA;&lt;p&gt;I have been trying to research this topic without any success. From what I've found the evidence is usually about the after affects that occur after &lt;strong&gt;major&lt;/strong&gt; earthquakes &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3475992/&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt; or they speak mainly upon how &amp;quot;earthquake sensitive people&amp;quot; try to predict earthquakes.&lt;/p&gt;&#xA;&lt;p&gt;For months now I've been experiencing vertigo symptoms &amp;quot;randomly&amp;quot; even when I, and the people around me, haven't felt any sort of earthquake movement at all; however, when I look up whether there has been an earthquake or not, the answer is always yes. Whether it was a strong earthquake that occurred in Mexico or a very mild one that occurred close by but not strong enough or close enough to feel, I can &amp;quot;feel&amp;quot; it just by how my body reacts. I seem to be extra sensitive than anyone around me, I've even felt small earthquakes that other people don't seem to feel.&lt;/p&gt;&#xA;&lt;p&gt;Just now some time around 6pm Costa Rican time while laying in bed, I felt a strong nauseas feeling which made me think it might've been because I hadn't eaten in a few hours, so I eat but I don't seem to get better, so I started thinking maybe I had low blood pressure or low blood sugar. Both of which were incorrect because I had eaten a bit of sugar during my meal and my BP was at a normal 110/70. So then I decided to look up if there had been any earthquakes and lo and behold, the was a 3.1 magnitud earthquake at 6:23pm about 15km from me, however it wasn't even strong enough for me or my roommates to feel.&lt;/p&gt;&#xA;" OwnerUserId="20779" LastActivityDate="2020-07-23T18:08:28.163" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19968" PostTypeId="2" ParentId="19283" CreationDate="2020-07-23T23:35:09.997" Score="0" Body="&lt;p&gt;This proably cannot be answered in a scientifically valid way at this time. There are hundreds of thousands of fossils across that span of time and no one has looked at all of them, &amp;quot;quality&amp;quot; is not something that is measured routinely. Worse there is a massive confounding factor, different formations have drastically different preservational quality. For instance the Solnhafen is a much earlier formation than the Lance formation but has drastically better preservation amd detail just becasue of the drastically different environments.&lt;/p&gt;&#xA;&lt;p&gt;Even trying to study this question would be swamped with problems just due to how drastically different the quantity of fossils are from each time period. Quality for fossils is strongly influenced by the local formation conditions (chemistry, grain size, burial speed, ect.) so it may be nearly impossible to answer without doing a specific study( it would be very expensive study). I am aware of no such study ever having been done and I know of no generally recognized difference but this is just one paleontologists experience.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2020-07-26T23:12:17.753" LastActivityDate="2020-07-26T23:12:17.753" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19970" PostTypeId="2" ParentId="19943" CreationDate="2020-07-24T16:52:23.033" Score="1" Body="&lt;p&gt;You have 3 completely unrelated dates in your question.&lt;/p&gt;&#xA;&lt;p&gt;Stephen Hawking suggested that humanity could kill itself in 100 years.  He's not the first to make that suggestion.   He's especially concerned about global warming and artificial intelligence (by the article).   Pandemic is obviously an issue today.  Overpopulation.  Nuclear war, asteroid strike, super-volcano, dubstep - all serious threats.&lt;/p&gt;&#xA;&lt;p&gt;Not to get all doom and gloom but there are reasons to be concerned for humanity over the next 100 years or so.  Hawking certainly has a point though I lean towards the idea of extinction being less likely, some non-extinction bumps on the road are certainly possible.&lt;/p&gt;&#xA;&lt;p&gt;The expanding sun (and no more eclipses cause the Sun is too big), will happen, slowly.  The sun increases in luminosity about 1% per 100 billion years and in diameter, maybe 1% every 200 million years.  In several hundred million years our sun might be too big for Earth and Earth could start dying.&lt;/p&gt;&#xA;&lt;p&gt;The counter-argument to this.   A sun-shield wouldn't be all that hard to build.  It's even being discussed today as a possible solution to climate change.    Not cheap, but not impossible, especially if we have a few hundred million years to get it done.&lt;/p&gt;&#xA;&lt;p&gt;The loss of CO2 probably will happen too though Earth's CO2 doesn't just go down neatly, it's more like an up and down with an overall downward trend.    If this continues, then in maybe 100 million years (a reasonably short time), we could face as CO2 shortage.   I know your article says 600 million - neither estimate is precise, but yes, a CO2 decline is probably going to happen at some point in the far future.&lt;/p&gt;&#xA;&lt;p&gt;The good news - we know how to fix that.   Burn coal.  Problem solved,  When we run out of coal, burn carbonate rock of other kinds.  There's billions and billions of tons of carbonate rock on Earth.   We can make CO2.  It's not that hard.    If we run out of carbonate rock (unlikely but possible) - toss some small comets rich in methane and CO2 into the ocean or onto unpopulated regions of Earth.  The comet idea might not be practical but it's certainly possible and many comets are rich in CO2 and CH4.&lt;/p&gt;&#xA;&lt;p&gt;Fun estimate.  Halley's comet has a mass of about 220 trillion kg.   At 280 PPM, the CO2 in the atmosphere has a mass of about 10 Halley's comets.    If Halley's comet is about 25% carbon compounds, 50% water, 25% other stuff - not the worst estimate and the CH4 yields more CO2 per mass, then all you'd need is maybe 2-4 Halley's comet equivalents every 10 million years or so to maintain CO2 on Earth.&lt;/p&gt;&#xA;&lt;p&gt;Halley's comet itself is too large but smaller comets could be tossed into unpopulated regions or into the ocean without much harm - and again, CO2 problem solved.   Not impossible.&lt;/p&gt;&#xA;&lt;p&gt;So, I think the trick is surviving Hawking's 100 year warning because the other problems are solvable with technology, at least for a time.   Likely beyond 600 million years.&lt;/p&gt;&#xA;" OwnerUserId="2717" LastActivityDate="2020-07-24T16:52:23.033" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="19971" PostTypeId="2" ParentId="19631" CreationDate="2020-07-24T19:31:37.777" Score="2" Body="&lt;p&gt;The suggestion above to check historical data to get an idea of the time to peak/ time of concentration, and a get sense of the general storm response time is a good one. There are also empirical methods to relate the catchment slope, runoff coefficient, etc. to the time to peak/ time of concentration, which sounds like what you are looking for. You can find examples of them in the &lt;a href=&quot;http://www.mto.gov.on.ca/english/publications/drainage/hydrology/section10.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;MTO Computational Methods&lt;/a&gt; webpage, more localized ones might exist wherever you are located. Look for the section on time to peak, although you may need other definitions in there to determine your inputs to that calculation (such as catchment slope).&lt;/p&gt;&#xA;&lt;p&gt;Keep in mind that 'runoff time' is not a specific term, and that the 'runoff time' for a full response may be extremely long, as nature tends to follow exponential responses trends with long tails in recession. However, the time to peak and time of concentration are more specific terms with definitions you can find and apply.&lt;/p&gt;&#xA;&lt;p&gt;In terms of how long to run the simulation, depends again based on what you are doing. For a real storm, there may be subsequest rainfall events before the full response is seen. If you just need the peak, then 2-3x the estimated time to peak from the methods above would likely be fine, depending on how flashy the catchment is. If you are running a hydrologic model of sorts, then run it for a long time to see the full response to check the response hydrograph, and compare that to real data to help validate your model.&lt;/p&gt;&#xA;" OwnerUserId="8440" LastActivityDate="2020-07-24T19:31:37.777" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19972" PostTypeId="2" ParentId="2813" CreationDate="2020-07-24T19:38:57.187" Score="2" Body="&lt;p&gt;For the data files themselves, NetCDF is extremely popular &lt;strong&gt;file format&lt;/strong&gt; for meteorological data which is typically associated with one or more standards like the &lt;a href=&quot;http://cfconventions.org/Data/cf-conventions/cf-conventions-1.8/cf-conventions.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;CF conventions&lt;/a&gt;, or &lt;a href=&quot;https://www.esipfed.org/student-fellow-blog/what-is-acdd&quot; rel=&quot;nofollow noreferrer&quot;&gt;ACDD&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;There are also standards in the sense of &lt;em&gt;transport standards&lt;/em&gt; for data as a service which is what I think you mean. The OGC standards have been mentioned above, and are examples of this (although you might also consider adding OGC SOS or Sensorthings to the list).&lt;/p&gt;&#xA;&lt;p&gt;The previous answer mentions THREDDS and NetCDF, but I would argue that OPeNDAP is more comparable to the OGC standards as a &lt;em&gt;data transport&lt;/em&gt; standard, whereas THREDDS / ERDDAP / Hyrax are the software that can communicate using that standard (ERDDAP can also serve out WMS for instance)&lt;/p&gt;&#xA;&lt;p&gt;The OPeNDAP standard, which is tightly connected to the NetCDF file format, is used extensively by a number of large national or international meteorological organizations including &lt;a href=&quot;https://gcw.met.no/sites/gcw.met.no/files/gcw-dm-guidelines-v0p5_0.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;WMO/GCW&lt;/a&gt; and &lt;a href=&quot;https://psl.noaa.gov/data/gridded/using_dods.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA&lt;/a&gt;,&lt;/p&gt;&#xA;&lt;p&gt;Depending on how broadly you define &amp;quot;Meteorlogical Data&amp;quot;, but you could also consider that IOOS and CIOOS use a mix of OGC SOS and OPeNDAP.&lt;/p&gt;&#xA;" OwnerUserId="14348" LastActivityDate="2020-07-24T19:38:57.187" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19973" PostTypeId="1" CreationDate="2020-07-24T19:58:17.070" Score="1" ViewCount="27" Body="&lt;p&gt;Cleaning data and turning it into a useable format that can be integrated with other datasets is a time-consuming task that earth scientists face when using sensor data. Most sensors output data in a highly idiosyncratic format that must typically be restructured before it can be meaningfully analyzed or imported into a database&lt;/p&gt;&#xA;&lt;p&gt;What software, libraries, frameworks, or tools do you use to perform these tasks? I'm most interested in things that handle time-series data from sensors, but I welcome answers that provide solutions for any field data processing and cleaning tasks&lt;/p&gt;&#xA;&lt;p&gt;I will compile answers below, starting with several that I have found:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Libraries&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://models.slf.ch/p/meteoio/&quot; rel=&quot;nofollow noreferrer&quot;&gt;MeteoIO&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Python&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://github.com/PermaData/DIT&quot; rel=&quot;nofollow noreferrer&quot;&gt;DIT&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14348" LastActivityDate="2020-07-24T19:58:17.070" Title="What software libraries, tools or frameworks do you use for turning tabular sensor data from the field into cleaned data files" Tags="|data-analysis|software|field-measurements|environmental-sensors|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19974" PostTypeId="2" ParentId="19337" CreationDate="2020-07-26T18:52:33.473" Score="0" Body="&lt;p&gt;I think because it shares a long geological history with the European plate, and the history of movement has been more or less rotational in-situ, and not as an independent plate with a distinct geological history. Take as an analogy the Anatolian plate, which is often considered a part of the Eurasian plate, &amp;quot;In some references, the Anatolian Plate is referred to as a &amp;quot;block&amp;quot; of continental crust still coupled to the Eurasian Plate. But studies of the North Anatolian Fault indicate that Anatolia is de-coupled from the Eurasian Plate.&amp;quot; Which would suggest the physical difference would rely on being decoupled from the parent plate. However it strikes me also that this can be a linguistic matter for ease of communication, it may just be a matter of convenience or description of Earth history, much in the same way you might talk about the Avalonia plate, or Baltica plate.&lt;/p&gt;&#xA;&lt;p&gt;So I think Iberia is a sub-plate or block, because of the shared Geological history with the Eurasian plate, rather then the independent history (Gondwana and India separately) seen within the geological history of the Indian plate.&lt;/p&gt;&#xA;" OwnerUserId="140" LastActivityDate="2020-07-26T18:52:33.473" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19976" PostTypeId="1" CreationDate="2020-07-26T20:48:34.933" Score="4" ViewCount="217" Body="&lt;p&gt;So after reading alot of literature on source localization, I found out that FK analysis is one of the most widely used methods to determine source location without explicitly calculating the difference in between the S and P phase arrivals. I had two questions regarding the same.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The output of the FK analysis algorithm is the Slowness,the back-azimuth and the corresponding power. This tells us the angle at which the source is present taking the center of the array geometry as the origin and the velocity of the wave which was received on site. My question is that, how to convert the Slowness vs Backazimuth plot to a  X distance vs Y distance graph.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Where do we use the information that there are surface waves too since we only look at the vertical components and not the radial ones of the seismometer?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Any help, clarification or resource provision would be highly appreciated! Forgive me for my insufficient knowledge about the topic since this isn't my major.&lt;/p&gt;&#xA;&lt;p&gt;Thank you :).&lt;/p&gt;&#xA;" OwnerUserId="20791" LastActivityDate="2020-07-26T20:48:34.933" Title="Beam forming FK analysis of a seismic wave" Tags="|seismology|seismic|data-analysis|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="19978" PostTypeId="1" CreationDate="2020-07-26T23:59:34.140" Score="2" ViewCount="81" Body="&lt;p&gt;I am a developer with a oceanographic side project.&#xA;I did some ML on wave &amp;amp; tide data and thought of publishing it in a paper. What are some good journals to send it to? Any recommendations?&lt;/p&gt;&#xA;&lt;p&gt;Thanks&#xA;El&lt;/p&gt;&#xA;" OwnerUserId="14963" LastEditorUserId="18081" LastEditDate="2022-08-04T09:08:54.683" LastActivityDate="2022-08-04T09:08:54.683" Title="What are good oceanographic journals" Tags="|oceanography|waves|tides|reference-request|wave-modeling|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19979" PostTypeId="1" AcceptedAnswerId="19996" CreationDate="2020-07-27T02:14:51.657" Score="5" ViewCount="531" Body="&lt;p&gt;It's possible to predict tide at a given location and at a given time reasonably well (e.g. &lt;a href=&quot;https://earthscience.stackexchange.com/questions/15313/predicting-low-tide&quot;&gt;predicting low tide&lt;/a&gt;). And there are tools available that make it possible to do this calculation for any location on earth at any time, such as &lt;a href=&quot;https://www.tpxo.net/otps&quot; rel=&quot;nofollow noreferrer&quot;&gt;OTPS&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Given that, it's possible calculate the annual maximum tide by calculating (sub)hourly data, and then taking the maximum. However, this is a pretty expensive way to do things - you're calculating 8.7k heights just to calculate a single maximum, and the calculations themselves are not particularly cheap. This quickly becomes a problem if you want to calculate a lot of locations.&lt;/p&gt;&#xA;&lt;p&gt;Annual maximum tide is not the same year to year, and from memory, the tides have a long-term cyclic nature of around 18 years (that is the lowest common multiple of the periods of all of the cyclic components).&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Is there a way of either analytically calculate the maximum tide height on a given day, or for a given year; or to calculate/estimate the &lt;em&gt;time&lt;/em&gt; of that maximum (from which it would be possible to calculate the height)?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I'm only interested in the long-term predictable component of tides - astronomical tides (and perhaps other things, like local orographic effects?). Not interested in storm surge or wave effects, or other things that are hard to predict in the long term.&lt;/p&gt;&#xA;" OwnerUserId="56" LastEditorUserId="56" LastEditDate="2020-07-27T14:45:19.960" LastActivityDate="2020-07-30T01:05:41.203" Title="Is it possible to predict the maximum daily/annual tide height without calculating hourly heights?" Tags="|tides|predictability|spectral-analysis|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19980" PostTypeId="2" ParentId="19979" CreationDate="2020-07-27T08:58:26.753" Score="6" Body="&lt;p&gt;Tidal tables are regularly calculated by several oceanographic institutes worldwide and handed out e.g. for navigation. Influencing factors (superficially spoken) are positions of celestial bodies like Sun, Moon, Venus, Mars, Jupiter and others, modelling of the propagation of the tidal bulges over the ocean basins, and topography and coastal features to calculate individual heights and, equally important, strength and timing of currents. These calculations are done for certain points of interest, like ports or coastal features or areas that could pose a risk to navigation. It is calculated and published for a year in advance.&lt;/p&gt;&#xA;&lt;p&gt;Modern electronic equipment displays values directly, else one would have to do it old style and search in the tables for adjacent places and a time interval and do a little interpolation manually.&lt;/p&gt;&#xA;&lt;p&gt;The tables are usually to the minute, to the tenth of a knot in current, and a decimeter in height, but of course small scale local features and meteorology and weather can have huge influence and significally alter the precomputed values. But weather prediciton has its limits which are days.&lt;/p&gt;&#xA;&lt;p&gt;Examples for tide tables:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.linz.govt.nz/sea/tides/tide-predictions/how-calculate-tide-times-heights&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.linz.govt.nz/sea/tides/tide-predictions/how-calculate-tide-times-heights&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.admiralty.co.uk/digital-services/admiralty-digital-publications/admiralty-totaltide&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.admiralty.co.uk/digital-services/admiralty-digital-publications/admiralty-totaltide&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;You can check tidal figures for individual times and places yourself with the help of a nautical chart viewer (e.g. navionics.com chartviewer, the red diamonds with a T inside), or by buying the &lt;a href=&quot;https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/330616/Format_1__ATT_4_Months_pp_.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;tables&lt;/a&gt; if one needs a copy, e.g. the ATT. I fear they cost a little something.&lt;/p&gt;&#xA;&lt;p&gt;All that said, there is the concept of the &amp;quot;&lt;a href=&quot;https://www.ausmarinescience.com/marine-science-basics/tides/highest-astronomical-tide/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Highest Astronomical Tide&lt;/a&gt;&amp;quot; HAT, which is part of the calculations. Simply spoken the highest possible tide if all the celestial bodies pull in the same direction. But meteorological influences (e.g. a storm) cannot be calculated beyond a few days.&lt;/p&gt;&#xA;&lt;p&gt;So, generally, this can not be done with exactness because of unforeseeable meteorological influences. If we ignore these (not advisable for nautical purposes) and for average meteorological conditions, the highest (or lowest) tide for a time and place can be taken from these tables.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-07-27T18:43:47.447" LastActivityDate="2020-07-27T18:43:47.447" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19981" PostTypeId="1" CreationDate="2020-07-27T09:23:29.573" Score="-1" ViewCount="314" Body="&lt;p&gt;I also see that weather forecast sites show temperatures decreasing starting from 3 to 4 pm, but the thermometer shows that it starts droping at sunset.&lt;/p&gt;&#xA;" OwnerUserId="20795" LastEditorUserId="6467" LastEditDate="2020-07-29T22:22:57.200" LastActivityDate="2020-07-29T22:22:57.200" Title="Why do the highest temperature levels occur at midday?" Tags="|meteorology|weather-forecasting|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="19982" PostTypeId="2" ParentId="19979" CreationDate="2020-07-27T13:38:07.927" Score="3" Body="&lt;p&gt;It depends on what you are trying to achieve.&lt;/p&gt;&#xA;&lt;p&gt;If you need exact figures for the maximum tidal height each day/year at a given location, there are no simple analytical solutions due to the complex nature of tides.&lt;/p&gt;&#xA;&lt;p&gt;If you are interested in ballpark figures (which are good enough for most recreational, but also some engineering applications), the maximum annual tidal height can be approximated by tidal datums, either the Mean High Water Springs (MHWS) or Mean Higher High Water (MHHW) depending on the tidal regime. If you would want to be extremely conservative, you could use Highest Astronomical Tide (HAT). Also taking the mean of MHWS/MHHW and HAT could be an option. This approximation would be suitable for 'regular' coastal and offshore locations. Complex bathymetry (e.g. funnel-shaped estuary) is trickier.&lt;/p&gt;&#xA;&lt;p&gt;This could potentially help you save some of the computational effort, as you would need to calculate the tidal datums once per location (rather than once per year per location).&lt;/p&gt;&#xA;" OwnerUserId="18907" LastActivityDate="2020-07-27T13:38:07.927" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19983" PostTypeId="1" CreationDate="2020-07-27T18:54:40.073" Score="2" ViewCount="213" Body="&lt;p&gt;In a Swedish Facebook group for &amp;quot;climate change skeptics&amp;quot; &lt;a href=&quot;https://www.facebook.com/erik.larsen.31586&quot; rel=&quot;nofollow noreferrer&quot;&gt;Erik Larsen&lt;/a&gt; has &lt;a href=&quot;https://www.facebook.com/groups/271018473802726/permalink/587771972127373/&quot; rel=&quot;nofollow noreferrer&quot;&gt;shared his calculation&lt;/a&gt; of how big part of temperature change can be attributed to human emissions of carbon dioxide. His reasoning goes as follows:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Temperature has raised by 1 °C since 1850.&lt;/li&gt;&#xA;&lt;li&gt;Carbon dioxide has raised by 30%.&lt;/li&gt;&#xA;&lt;li&gt;Carbon dioxide only constitute 4% of the greenhouse gases (the main part consists of water vapor).&lt;/li&gt;&#xA;&lt;li&gt;Carbon dioxide is only 1/4 as efficient as water vapor per molecule as a greenhouse gas.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;From this he concludes that the temperature raise from carbon dioxide is only 1 °C × 0.30 × 0.04 × 1/4 = &lt;strong&gt;0.003 °C&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I have &lt;a href=&quot;https://www.facebook.com/groups/271018473802726/?post_id=587771972127373&amp;amp;comment_id=587854978785739&quot; rel=&quot;nofollow noreferrer&quot;&gt;tried to explain&lt;/a&gt; (in Swedish) that this calculation is not correct, but of course he refuses to accept that and writes that my objections are not logical. Today I wrote that it's lucky for him that his calculation is not peer-reviewed and suggested that I could share it in a physics and/or mathematics group for review. He complied. So here it is.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;What do you think of his calculation?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="20799" LastEditorUserId="18081" LastEditDate="2020-07-28T07:17:03.543" LastActivityDate="2020-07-29T04:37:46.180" Title="Review of calculation of CO$_2$ contribution to warming" Tags="|climate-change|co2|human-influence|" AnswerCount="4" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="19984" PostTypeId="2" ParentId="19983" CreationDate="2020-07-27T21:38:48.440" Score="5" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;From this he concludes that the temperature raise from carbon dioxide is only 1 °C × 0.30 × 0.04 × 1/4 = &lt;strong&gt;0.003° C&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;His number for the amount of CO&lt;sub&gt;2&lt;/sub&gt; is high. A better value is 0.027 rather than 0.04. That does not mean that the correct answer is 0.002° C. This argument is completely fallacious. The author of this calculation is playing numerological games. There is zero justification for multiplying these numbers.&lt;/p&gt;&#xA;&lt;p&gt;Artificially adding carbon dioxide to the Earth's atmosphere is a forcing agent. Doing so increases the Earth's average temperature, which has a side effect of increasing evaporation. This forced feedback is a rather nasty side effect.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, artificially adding water vapor to the Earth's atmosphere is not a forcing agent. Doing so would merely increase the local chance of precipitation. Excess water vapor very quickly rains itself out of the atmosphere. Excess carbon dioxide does not rain itself out of the atmosphere. Plants and rocks take a long time to absorb excess carbon dioxide.&lt;/p&gt;&#xA;&lt;p&gt;As the internet gives these people influence that far exceed their numbers, it is important to rebut their arguments. As I already mentioned, there is zero justification for multiplying the numbers in the way the author of this argument did. This is what science deniers do: They create completely fallacious arguments.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-07-27T21:38:48.440" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19985" PostTypeId="2" ParentId="19983" CreationDate="2020-07-28T00:58:13.400" Score="9" Body="&lt;p&gt;This reminds me of using Bjørn Lomborg's book in statistics, as examples how not to do statistics, his calculations never make any sense or just make unfounded leaps to conclusions.&lt;/p&gt;&#xA;&lt;p&gt;Erik seems to have the same problem he just throws numbers together with no rhyme or reason.&lt;/p&gt;&#xA;&lt;p&gt;Let's just break down his calculation.&lt;/p&gt;&#xA;&lt;p&gt;1 °C × 0.30 × 0.04 &lt;strong&gt;× 1/4&lt;/strong&gt; = 0.003 °C.&lt;/p&gt;&#xA;&lt;p&gt;Why are we multiplying by 0.25, he says CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; is only 25% as good as water, but water is nowhere in this calculation, there is no reason for this to even be here much less to be multiplied. Also why can't he solve 1/4?&lt;/p&gt;&#xA;&lt;p&gt;1 °C × 0.30 &lt;strong&gt;× 0.04&lt;/strong&gt; = ??&lt;/p&gt;&#xA;&lt;p&gt;This is just plain wrong, CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; comprises 0.04% of total gas and ~93% of trace gasses, even more of greenhouse gasses, unless he is arguing some undiscovered change in nitrogen or argon is acting as a greenhouse gas, this has no place in the calculation. Also again why is he multiplying by the increase in CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;? Does he think ALL gasses in the atmosphere increased by 30% that the atmosphere got 30% heavier in 150 years?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;1 °C × 0.30&lt;/strong&gt; = ??&lt;/p&gt;&#xA;&lt;p&gt;What is this calculation meant to do? One times anything is always whatever you multiply it by, so all you are calculating is units, but units are ignored in the calculation, and what purpose does multiplying degrees of change times percentage of increase do?&lt;/p&gt;&#xA;&lt;p&gt;There is no point arguing with Larsen, either he does not understand math (in which case you are wasting your time) or he is purposefully being misleading (and it just gives him attention). Either way there is no benefit to arguing with him. Your best case is he does not understand math otherwise he is just using a completely unjustified string of numbers to have something that looks scientific because it has a equation in it counting on the fact most people who read it don't know enough about math to see the problem.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2020-07-28T17:37:22.100" LastActivityDate="2020-07-28T17:37:22.100" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19986" PostTypeId="2" ParentId="19983" CreationDate="2020-07-28T09:25:20.193" Score="3" Body="&lt;p&gt;&lt;strong&gt;&lt;em&gt;tl;dr&lt;/em&gt;–&lt;/strong&gt; This sounds like silliness through-and-through.  Addressing it as though it were a real scientific calculation would seem to be missing the forest for the trees.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Temperature has raised by 1 °C since 1850.&lt;/li&gt;&#xA;&lt;li&gt;Carbon dioxide has raised by 30%.&lt;/li&gt;&#xA;&lt;li&gt;Carbon dioxide only constitute 4% of the greenhouse gases (the main part consists of water vapor).&lt;/li&gt;&#xA;&lt;li&gt;Carbon dioxide is only 1/4 as efficient as water vapor per molecule as a greenhouse gas.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;From this he concludes that the temperature raise from carbon dioxide is only 1 °C × 0.30 × 0.04 × 1/4 = &lt;strong&gt;0.003 °C&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This doesn't make any sense.  Someone's just started with a number, stringing together random multiplication factors.  Presumably they could just keep multiplying by other numbers, basically at random, if they wanted.&lt;/p&gt;&#xA;&lt;p&gt;How do you fix this?  You don't.  &lt;a href=&quot;https://en.wikipedia.org/wiki/Not_even_wrong&quot; rel=&quot;nofollow noreferrer&quot;&gt;There aren't any errors to be fixed.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;By analogy, if someone rips a piece of paper, you might be able to tape it back together.  But if someone incinerates a piece of paper, then it's not really productive to see it as &amp;quot;&lt;em&gt;paper&lt;/em&gt;&amp;quot; anymore.  Likewise, this isn't a &amp;quot;&lt;em&gt;logical argument&lt;/em&gt;&amp;quot; to be fixed; you can't &amp;quot;&lt;em&gt;fix&lt;/em&gt;&amp;quot; this because there's not enough of something there to be &amp;quot;&lt;em&gt;fixed&lt;/em&gt;&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;I'd speculate that you know this.  Presumably it's just that &lt;a href=&quot;https://xkcd.com/386/&quot; rel=&quot;nofollow noreferrer&quot;&gt;someone's wrong on teh interwebz and you'd wanted to fix it&lt;/a&gt;.  But I doubt that you'll manage to identify a subtle mistake in their logical analysis as I doubt that there was any logical analysis in the first place.&lt;/p&gt;&#xA;" OwnerUserId="10840" LastActivityDate="2020-07-28T09:25:20.193" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19987" PostTypeId="2" ParentId="19981" CreationDate="2020-07-28T10:04:56.133" Score="2" Body="&lt;p&gt;The highest temperature of the day typically occurs well before sunset but well after local noon (which in summertime is about 1:00 PM in areas that use daylight savings time). The reason for the lag between noon and the time at which temperature reaches a maximum is because is that the Sun continues to warm the ground, water, and air well after noon has passed. It's only when the Sun gets low enough on the horizon that radiational cooling to space exceeds the diminishing radiational heating from the Sun.&lt;/p&gt;&#xA;&lt;p&gt;There's a similar four to six week lag between the longest day of the year and the hottest days of the year. Just as the Sun continues to provide warmth during the day well after local noon, the Sun continues to provide warmth during the year well after the summer solstice.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-07-28T10:04:56.133" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19988" PostTypeId="2" ParentId="19978" CreationDate="2020-07-28T13:41:43.637" Score="3" Body="&lt;p&gt;When searching for a place to publish Earth Science stuff, have a look at the two big continental scientific societies: the American Geophysical Union (AGU) and the European Geosciences Union (EGU). Both have a wide array of publications in the various fields of geosciences. AGU has &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/journal/21699291&quot; rel=&quot;nofollow noreferrer&quot;&gt;JGR Oceans&lt;/a&gt;, while EGU has &lt;a href=&quot;https://www.ocean-science.net/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ocean Science&lt;/a&gt; (open access). If you want to reach a broader, less specialized audience, you could also aim for &lt;a href=&quot;https://www.frontiersin.org/journals/earth-science#&quot; rel=&quot;nofollow noreferrer&quot;&gt;Frontiers in Earth Science&lt;/a&gt; (open access): they have a Hydrosphere section.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-07-28T13:41:43.637" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19989" PostTypeId="2" ParentId="19983" CreationDate="2020-07-28T22:11:02.947" Score="1" Body="&lt;p&gt;The &amp;quot;calculation&amp;quot; - 1 °C × 0.30 × 0.04 × 1/4 = 0.003 °C is meaningless. Rather than attempt to show that directly my response would be to ask &amp;quot;if the contribution of CO2 to 1 °C of warming &lt;em&gt;really were&lt;/em&gt; only 0.003 °C then &lt;em&gt;what caused the other 0.997 °C of warming&lt;/em&gt;?&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;Seems clear that water vapour, even if having 4 times the greenhouse potential of CO2 does not - and if there are other factors at work what are they and why are those omitted?&lt;/p&gt;&#xA;&lt;p&gt;Ultimately the question of how much CO2 contributed to 1 °C of surface air temperature rise that has taken place must be answered through understanding the climate processes that are at work, including the Greenhouse Effect as climate science understands it.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="18145" LastEditDate="2020-07-28T22:48:29.670" LastActivityDate="2020-07-28T22:48:29.670" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19990" PostTypeId="2" ParentId="19350" CreationDate="2020-07-28T22:28:05.300" Score="2" Body="&lt;p&gt;(Related to answers to the question &lt;a href=&quot;https://earthscience.stackexchange.com/questions/18534/thermal-expansion-of-earth&quot;&gt;Thermal expansion of Earth&lt;/a&gt;, which I only realized after having saved this answer. So, in principle, a double post, but I was asked to undelete :-))&lt;/p&gt;&#xA;&lt;p&gt;Earth's thermal history may give some hints -- not sure if this is an actual answer to the question. It seems like Earth's radius depends on the layering of mantle convection, and that though there were significant changes during the Archean Eon and earlier, the current and recent (since the late Archean) shrinking rate is slow (a reduction of 12km in radius in 2.5Gy).&lt;/p&gt;&#xA;&lt;p&gt;Source:&#xA;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S167498711200148X&quot; rel=&quot;nofollow noreferrer&quot;&gt;Expanding-contracting Earth by Tsuchiya et al. 2013&lt;/a&gt; in Geoscience Frontiers&lt;/p&gt;&#xA;&lt;hr&gt;&#xA;&lt;p&gt;&lt;em&gt;Questions that remain:&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;What about the core ?&lt;/p&gt;&#xA;&lt;p&gt;And is mass loss or gain from astronomical processes significant enough ?&lt;/p&gt;&#xA;&lt;p&gt;I would like to add that WGS 84 is a reference ellipsoid, and height values can be (are) given as positive or negative numbers. They can be updated every now and then by satellite. Also, I would assume that tectonic processes or local anomalies may by far outweigh any signal from thermal shrinking over the course of next centuries or even millennia (speculation).&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorUserId="6298" LastEditorDisplayName="user20217" LastEditDate="2021-02-27T08:03:42.997" LastActivityDate="2021-02-27T08:03:42.997" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19992" PostTypeId="1" AcceptedAnswerId="19994" CreationDate="2020-07-29T13:27:52.657" Score="3" ViewCount="207" Body="&lt;p&gt;With all the COVID-19 stuff going on, I feel the usage of alcohol-based hand sanitizers has increased many fold.&#xA;I wonder what happens to all that evaporated alcohol in the atmosphere.&#xA;How soon does alcohol react in environment and what other substances are formed?&lt;/p&gt;&#xA;" OwnerUserId="20805" LastEditorUserId="6467" LastEditDate="2020-07-29T22:27:05.573" LastActivityDate="2022-11-12T20:39:20.073" Title="Does evaporated hand sanitizer pollute the environment?" Tags="|atmosphere|atmospheric-chemistry|evaporation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="19993" PostTypeId="1" CreationDate="2020-07-29T15:59:41.730" Score="1" ViewCount="88" Body="&lt;p&gt;Would you please let me know where I can find/download reliable snowfall rate datasets?&lt;/p&gt;&#xA;&lt;p&gt;I am looking for multiple weather stations (in different regions) or field measured data, that contain both solid/liquid precipitation data.&lt;/p&gt;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="20807" LastEditorUserId="20807" LastEditDate="2020-08-02T16:50:37.047" LastActivityDate="2020-08-03T19:52:08.447" Title="Where to find reliable snowfall rate data?" Tags="|hydrology|precipitation|earth-observation|snow|weatherdata|" AnswerCount="1" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19994" PostTypeId="2" ParentId="19992" CreationDate="2020-07-29T17:59:45.640" Score="7" Body="&lt;p&gt;Assuming you are talking about ethanol: it is a common chemical substance, generated naturally from e.g. rotting fruits. So any pollution from hand sanitizers should be negligible.&lt;/p&gt;&#xA;&lt;p&gt;What happens to the alcohol in the atmosphere is an interesting sequence of reactions. I took the info below from an article (see link below).&lt;/p&gt;&#xA;&lt;p&gt;In the air, ethanol is oxidized quickly (half-life is a few days) into &lt;a href=&quot;https://en.wikipedia.org/wiki/Acetaldehyde&quot; rel=&quot;noreferrer&quot;&gt;acetaldehyde&lt;/a&gt; &lt;span class=&quot;math-container&quot;&gt;$CH_3CHO$&lt;/span&gt;, which is further oxidized into other compounds, most of which are harmless. However, if the air contains nitrogen dioxide &lt;span class=&quot;math-container&quot;&gt;$NO_2$&lt;/span&gt;, it can form &lt;a href=&quot;https://en.wikipedia.org/wiki/Peroxyacetyl_nitrate&quot; rel=&quot;noreferrer&quot;&gt;peroxyacetyl nitrate&lt;/a&gt; &lt;span class=&quot;math-container&quot;&gt;$CH_3C(O)OONO_2$&lt;/span&gt;, which is dangerous.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.scielo.br/pdf/jbchs/v8n5/a02v08n5.pdf&quot; rel=&quot;noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20809" LastActivityDate="2020-07-29T17:59:45.640" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="19995" PostTypeId="1" CreationDate="2020-07-29T21:04:47.920" Score="4" ViewCount="826" Body="&lt;p&gt;According to &lt;a href=&quot;https://iopscience.iop.org/article/10.1088/1748-9326/aa8390&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Accounting for water formation from hydrocarbon fuel combustion in life cycle analyses&lt;/em&gt;&lt;/a&gt;, water is &lt;em&gt;created&lt;/em&gt; by burning hydrocarbon fuels. It seems like a major thing to exclude from &amp;quot;reasons the sea levels are increasing&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;From the paper:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The annual global formation of water from combustion of hydrocarbon&#xA;fuels from 2005–2015 amounted to an average of &lt;span class=&quot;math-container&quot;&gt;$1.2 \times 10^{13} kg⋅yr^{-1}$&lt;/span&gt;, as&#xA;shown in figure 1. By comparison, the atmosphere is estimated to hold&#xA;on average approximately &lt;span class=&quot;math-container&quot;&gt;$1.3 \times 10^{16}$&lt;/span&gt; kg of water, while the global&#xA;rates of irrigation-induced and natural evaporation are on the orders&#xA;of &lt;span class=&quot;math-container&quot;&gt;$10^{15}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$10^{17} kg⋅yr^{-1}$&lt;/span&gt;, respectively.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I understand from the figures, the amount of water introduced into the atmosphere is small compared to irrigation and natural evaporation, but that is only dealing with water that is already there.  This paper details that we are essentially pulling hydrogen out of the earth, combining it with atmosphere oxygen and creating water.&lt;/p&gt;&#xA;&lt;p&gt;Water vapor is already listed as a GHG, so maybe it is just being swept along with that term?&lt;/p&gt;&#xA;&lt;p&gt;I have to be making a connection that doesn't exist, right? Otherwise it would be noticed by someone / anyone else.&lt;/p&gt;&#xA;&lt;p&gt;Make me understand why I am wrong to think that the creation of water by burning hydrocarbon fuels is adding to the amount of water in the oceans.&lt;/p&gt;&#xA;&lt;p&gt;Thank you,&lt;/p&gt;&#xA;" OwnerUserId="20806" LastEditorUserId="18088" LastEditDate="2024-02-17T13:12:20.030" LastActivityDate="2024-02-17T13:12:20.030" Title="Why is the creation of water from the combustion of hydrocarbons not listed as a cause for rising sea levels?" Tags="|atmosphere|climate-change|sea-level|fossil-fuel|" AnswerCount="2" CommentCount="17" ContentLicense="CC BY-SA 4.0" />
  <row Id="19996" PostTypeId="2" ParentId="19979" CreationDate="2020-07-30T01:05:41.203" Score="2" Body="&lt;p&gt;You are looking for an easy solution to the local maxima of&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\sum_i a_i \sin(\theta_i+\omega_i t)$$&lt;/span&gt;&#xA;This means solving for solutions to&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\sum_i a_i \omega_i \cos(\theta_i+\omega_i t) = 0$$&lt;/span&gt;&#xA;This is a transcendental equation with multiple terms with different frequencies. While there are many ways to find such maxima that vary in computational complexity and computational cost, there typically is no nice and easy way to find such maxima.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-07-30T01:05:41.203" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="19997" PostTypeId="1" CreationDate="2020-07-30T02:41:43.673" Score="4" ViewCount="92" Body="&lt;p&gt;I am trying to formulate a research topic centered around the environmental effects of general aviation's continued use of leaded gasoline (containing tetraethyllead) to power piston aircraft. In particular I am interested in studying the extent to which lead levels may or may not be elevated around airports that serve such small piston aircraft.&lt;/p&gt;&#xA;&lt;p&gt;Are there any extant remote sensing techniques for detecting the presence of lead particulate in the atmosphere or soil? Can spectroscopy be used to detect lead in the same way as satellites do for other pollutants, like CO2 and methane?&lt;/p&gt;&#xA;&lt;p&gt;If such remote sensing capability exists -- whether through satellites or something more small-scale -- does anyone know if NASA has any equipment capable of collecting such data?&lt;/p&gt;&#xA;" OwnerUserId="20810" LastActivityDate="2020-07-30T02:41:43.673" Title="Lead remote sensing?" Tags="|remote-sensing|satellites|spectral-analysis|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="19998" PostTypeId="2" ParentId="19995" CreationDate="2020-07-30T07:53:14.837" Score="11" Body="&lt;p&gt;1.2 x 10^13 kg equals 12,000,000,000,000 l water. One liter equals 0.001 m³, while one km³ equals one billion (1 x 10^9) m³. So we're supposedly adding 12 km³ water to the atmosphere per year.&lt;/p&gt;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://en.wikipedia.org/wiki/Ocean#Oceanic_divisions&quot; rel=&quot;noreferrer&quot;&gt;wikipedia&lt;/a&gt; the total oceanic surface is about 361,900,000 km². If we spread the added amount of water over all the oceans, we end up with a sea level rise of 0,03316 mm per year. The &lt;a href=&quot;https://de.wikipedia.org/wiki/Meeresspiegelanstieg_seit_1850#Ursachen&quot; rel=&quot;noreferrer&quot;&gt;german wikipedia page on sea level rise&lt;/a&gt; claims - based on the  5th chapter of the Fourth Assessment Report by the IPCC from 2007 - that the annual sea level rise between 1993 and 2003 due to thermal expansion was about 1,6 ± 0,50 mm.&lt;/p&gt;&#xA;&lt;p&gt;Since we didn't take into account sinking surface above oceanic hydrocarbon sources or the increased atmospheric capacity for water vapour due to heating, which both are connected to the effect you are interested in, I'd estimate there is an existing, but almost negligible contribution to sea level rise. Other effects contribute way more - and all of them will likely peter out, once we reduce fossil fuel consumption significantly.&lt;/p&gt;&#xA;" OwnerUserId="14194" LastEditorUserId="14194" LastEditDate="2020-07-31T06:36:24.687" LastActivityDate="2020-07-31T06:36:24.687" CommentCount="19" ContentLicense="CC BY-SA 4.0" />
  <row Id="19999" PostTypeId="1" CreationDate="2020-07-30T15:48:26.630" Score="1" ViewCount="191" Body="&lt;p&gt;I heard that hot weather in the summer makes the pastel colors of the sunset sky more vivid and more red? Is this true? But I also heard that in the winter, the colors of the sunset sky are brighter and more pronounced. How could both of these be true?&lt;/p&gt;&#xA;" OwnerUserId="17923" LastActivityDate="2020-08-03T00:02:31.507" Title="Color of Sunsets" Tags="|meteorology|atmosphere|sun|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20000" PostTypeId="1" CreationDate="2020-07-30T16:07:27.923" Score="1" ViewCount="126" Body="&lt;p&gt;The question might be in an opinion-based grey zone. If it is, I apologize.&lt;/p&gt;&#xA;&lt;p&gt;My wife and I want to get informed about climate change.&#xA;We want to read a book (no online course etc.) and it should be either in English or available in Portuguese and German. It is supposed to &amp;quot;start from the beginning&amp;quot; e.g. treating us as people that almost don't know anything about it.&#xA;We wish a rather scientific approach (for example with references to papers) and it should of course talk about the strongest evidences of the existence of the climate problem and its causes.&lt;/p&gt;&#xA;&lt;p&gt;After some short internet research we thought of &amp;quot;&lt;a href=&quot;https://www.goodreads.com/book/show/10541833-the-rough-guide-to-climate-change&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Rough Guide to Climate Change of Robert Henson&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The question is: Would this be a good choice?&#xA;Does it fulfill our requirements? And since it is (at least) 9 years old, is it maybe too old?&#xA;Maybe some significant findings were added in this time.&#xA;And if it isn't a good choice can you recommend other books?&lt;/p&gt;&#xA;&lt;p&gt;Thanks in advance&lt;/p&gt;&#xA;" OwnerUserId="18779" LastActivityDate="2020-07-31T21:02:42.430" Title="Book Introduction to Climate Change" Tags="|climate-change|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20001" PostTypeId="2" ParentId="19999" CreationDate="2020-07-30T17:24:57.110" Score="1" Body="&lt;p&gt;A complex interplay of scattering (Rayleigh-scattering for particles smaller than the wavelength, and Mye-scattering for larger particles), sun angle and attenuation of light on it's path thorugh the atmopshere determine the sky&#xA;colour.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Rayleigh_scattering&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Rayleigh_scattering&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(Linked in a similar question here)&#xA;&lt;a href=&quot;http://www.severewx.com/Radiation/scattering.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.severewx.com/Radiation/scattering.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://gsp.humboldt.edu/OLM/Courses/GSP_216_Online/lesson2-1/scatter.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://gsp.humboldt.edu/OLM/Courses/GSP_216_Online/lesson2-1/scatter.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So, bringing it all together, it is not the absolute temperature that determines the colour of the sky, but generally the state of the atmopshere at your place with its aerosols and moisture, be it winter or summer.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastActivityDate="2020-07-30T17:24:57.110" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20002" PostTypeId="2" ParentId="20000" CreationDate="2020-07-31T04:02:53.037" Score="0" Body="&lt;p&gt;Here is a free (at least until tomorrow) download:&lt;br /&gt;&#xA;&lt;a href=&quot;https://link.springer.com/book/10.1007%2F978-94-007-5757-8&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate Change Science: A Modern Synthesis&lt;br /&gt;&#xA;Volume 1 - The Physical Climate&lt;br /&gt;&#xA;G. Thomas FarmerJohn Cook&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2020-07-31T04:02:53.037" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20003" PostTypeId="2" ParentId="20000" CreationDate="2020-07-31T06:46:03.980" Score="0" Body="&lt;p&gt;Since German books are ok with you, I definitely can recommend&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Klimawandel und Klimadynamik&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;by Mojib Latif.&lt;/p&gt;&#xA;&lt;p&gt;It costs about 10 € and covers all the basics on climate change and dynamics, though it is 11 years old. Still, the author is one of the leading scientists on climate in Germany and teaches excellent courses for Bachelor students.&lt;/p&gt;&#xA;" OwnerUserId="14194" LastActivityDate="2020-07-31T06:46:03.980" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20004" PostTypeId="1" AcceptedAnswerId="20006" CreationDate="2020-07-31T14:53:16.180" Score="2" ViewCount="85" Body="&lt;p&gt;I'm kind new to this hole thing of dinosaurs that I'm really interested in, are there any good books/websites/webpages to study the biology of pre-historic creatures? Dinosaurs, mammals, fishes, anything that is not alive anymore. Also, any good books about the history of how these species evolved and the history behind them would be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="20814" LastActivityDate="2020-08-01T09:18:05.217" Title="How to start studying dinosaurs and pre-historic mammals/sea creatures" Tags="|paleontology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20005" PostTypeId="1" AcceptedAnswerId="20009" CreationDate="2020-07-31T16:07:35.697" Score="1" ViewCount="56" Body="&lt;p&gt;Every year I see &lt;a href=&quot;https://weather.com/en-IN/india/monsoon/news/2020-07-31-assam-flood-situation-improves-12-lakh-people-remain-distressed&quot; rel=&quot;nofollow noreferrer&quot;&gt;these&lt;/a&gt; sort of news articles where states are flooded particularly due to their geographical location and vicinity to flood prone areas, however year after year there is no improvement in the same. Every year lots of lives are lost, properties destroyed, and people displaces and this made me wonder is there no good plan that such an area can follow?&lt;/p&gt;&#xA;&lt;p&gt;Is there nothing the Government can do for the remainder of the year so that they can prevent and minimize damage? Are there places like this which have successfully minimized damage over the years?&lt;/p&gt;&#xA;&lt;p&gt;I believe the loss of life and property is too high and happens every year or so hence investing in solutions must be a good choice still we don't see it happening at a large enough scale to make a difference is it due to unwillingness of the bureaucracy?&lt;/p&gt;&#xA;" OwnerUserId="20815" LastEditorUserId="20815" LastEditDate="2020-07-31T23:58:21.033" LastActivityDate="2020-08-02T10:57:13.157" Title="How to curb losses during annual heavy rainfalls" Tags="|rain|natural-disasters|flooding|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20006" PostTypeId="2" ParentId="20004" CreationDate="2020-07-31T16:24:52.550" Score="2" Body="&lt;p&gt;Here's what it takes to really &lt;em&gt;study&lt;/em&gt; this: you need to go through the whole bachelor program for geoscientists, that includes fundamental geodynamics like plate tectonics, magmatism, volcanism, volcanic and metamorphic rocks and generally the cycles that make up &lt;em&gt;earth's internal dynamics&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Then there is the huge field of external factors, like sediment geology (that's really complicated stuff), weathering and transport and how soils come to being, diagenesis and the structures sediments can form and their classifications. Role of the ocean (that's where it starts, before all) and the atmosphere, of course.&lt;/p&gt;&#xA;&lt;p&gt;When through that, usually 4 semesters or so, you can start to specialize. For paleontolgy you need knowledge of earth history, of course, it's subdivision, and the conditions at certain times as far as they are known. Once that's done, then comes real paleontology: Animals (invertebrates and vertebrates), plants, and their development, biological evolution (that's frequently underrated, I find), taphonomy, ... For a sturdy base count another 2-4 semesters.&lt;/p&gt;&#xA;&lt;p&gt;You may see that even a bunch of websites, maybe all of them together, cannot replace actual study. I am not aware of any site that even gives a reasonable overview of the field. Geoscience, and thus paleontology, touch many fields of natural science.&lt;/p&gt;&#xA;&lt;p&gt;That said, when asked &amp;quot;How to learn about animal paleontology ?&amp;quot; I allways mention &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/1118406842&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Micheal Benton, Vertebrate Paleontology&lt;/a&gt;. It needs a basic understanding of geoscience, evolution and skeleton anatomy. Functional morphology, phylogeny and an overview over sediment geology and earth history also won't harm, but you could give it a try. Some things are explained in between.&lt;/p&gt;&#xA;&lt;p&gt;I'd recommend to at least get a good introduction and overview into geology, in form of one or two books on the matter. Maybe a colleague knows other good books on the subject. Actually, I'd like to update my bookshelf myself :-)&lt;/p&gt;&#xA;&lt;p&gt;Also, Museums of Natural History have publications that could interest you, but best would probably to sacrifice some time, visit them and then browse their book shops. Depending on your time and where you are.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-08-01T09:18:05.217" LastActivityDate="2020-08-01T09:18:05.217" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20007" PostTypeId="2" ParentId="20000" CreationDate="2020-07-31T21:02:42.430" Score="2" Body="&lt;p&gt;I highly recommend &lt;em&gt;Climate: A Very Short Introduction&lt;/em&gt; and &lt;em&gt;Climate Change: A Very Short Introduction&lt;/em&gt;, both by Mark Maslin and published through Oxford U Press's highly-regarded VSI series. I use both books when teaching college-level classes where an understanding of climate and climate change are important to the subject matter but are not the sole focus of the class.&lt;/p&gt;&#xA;" OwnerUserId="18595" LastActivityDate="2020-07-31T21:02:42.430" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20009" PostTypeId="2" ParentId="20005" CreationDate="2020-08-01T03:29:58.587" Score="2" Body="&lt;p&gt;Flood control measures largely depend on:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The amount of money available to create flood control measures&lt;/li&gt;&#xA;&lt;li&gt;The availability of raw materials that could be used to create such&#xA;measures&lt;/li&gt;&#xA;&lt;li&gt;The locality of the potentially flood affected region&lt;/li&gt;&#xA;&lt;li&gt;The source of potential flooding  and its relation to the region that&#xA;could be flooded.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;One extreme example is &lt;a href=&quot;https://en.wikipedia.org/wiki/Bangladesh&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bangladesh&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Most of Bangladesh is located within the &lt;a href=&quot;https://en.wikipedia.org/wiki/River_delta&quot; rel=&quot;nofollow noreferrer&quot;&gt;delta region&lt;/a&gt; of the Ganges and Brahmaputra Rivers; that is where the two rivers meet the ocean.&lt;/p&gt;&#xA;&lt;p&gt;The region is flat and devoid of easily accessible sources of natural rock. Elsewhere, competent rock, such a basalt, can be located, extracted and crushed to form aggregate  that can be used as a construction material. Because Bangladesh lacks such rock sources it needs to bake clay to create a form of aggregate.&lt;/p&gt;&#xA;&lt;p&gt;Being positioned at the tail end of two major rivers, the government of Bangladesh does not have control of significant reaches of the rivers to create flood control structures further upstream.&lt;/p&gt;&#xA;&lt;p&gt;Politically and religiously, flood control measures on either of these rivers could cause a lot Hindus to become very upset.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Economy_of_Bangladesh&quot; rel=&quot;nofollow noreferrer&quot;&gt;Financially&lt;/a&gt;, Bangladesh is a poor country with a population of 162 million people. If it were able to construct flood control devices on the two rivers, it would also need to construct flood prevention devices along its coast as the combination of flood waters from the rivers and high tides from the ocean can exacerbate flooding and its effects on the country.&lt;/p&gt;&#xA;&lt;p&gt;Finally, rising sea levels from climate change are only going to make matters worse for Bangladesh, because it is a very low lying country.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Edit 2 August 2020&lt;/p&gt;&#xA;&lt;p&gt;Concerning successful flood control measures, two quickly come to mind, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Thames_Barrier&quot; rel=&quot;nofollow noreferrer&quot;&gt;Thames Barrier&lt;/a&gt; in London, England and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Aswan_Dam&quot; rel=&quot;nofollow noreferrer&quot;&gt;Aswan Dam&lt;/a&gt; in Egypt, particularly the Aswan High Dam.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Thames Barrier is a movable barrier system that is designed to prevent the floodplain of most of Greater London from being flooded by exceptionally high tides and storm surges moving up from the North Sea. It has been operational since 1982. When needed, it is closed (raised) during high tide; at low tide, it can be opened to restore the river's flow towards the sea.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Based on the success of the Low Dam, then at its maximum utilization, construction of the High Dam became a key objective of the government following the Egyptian Revolution of 1952; with its ability to better control flooding, provide increased water storage for irrigation and generate hydroelectricity the dam was seen as pivotal to Egypt's planned industrialization. Like the earlier implementation, the High Dam has had a significant effect on the economy and culture of Egypt.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2020-08-02T10:57:13.157" LastActivityDate="2020-08-02T10:57:13.157" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20012" PostTypeId="1" CreationDate="2020-08-02T01:48:10.317" Score="1" ViewCount="67" Body="&lt;p&gt;Why is it that some years have significantly more thunderstorms than others while other years have significantly less? For example, in 2008, there were 15 thunderstorm days in Asheville but above 40 in recent years. Why is this?&lt;/p&gt;&#xA;" OwnerUserId="17923" LastActivityDate="2020-08-02T01:48:10.317" Title="Thunderstorm Frequency Depending on the Year" Tags="|meteorology|climate-change|thunderstorm|storms|" AnswerCount="0" CommentCount="3" ClosedDate="2020-08-02T11:34:51.003" ContentLicense="CC BY-SA 4.0" />
  <row Id="20015" PostTypeId="2" ParentId="19999" CreationDate="2020-08-02T23:35:31.917" Score="0" Body="&lt;p&gt;In addition to the atmospheric color effects described by a_donda, there can also be color variations in the sun itself during a single sunrise or sunset, which are again caused by atmospheric effects.  Here too, gradients on temperature and density are more important than an overall hot or cold temperature.  These gradients cause refraction effects that may magnify the ordinarily tiny separation of sunlight into its different colors, causing green or even blue colors to briefly appear in the rising or setting sun.  Sunsets over water are a common setting for viewing such &lt;strong&gt;green flashes&lt;/strong&gt;, but I have seen them at &lt;em&gt;sunrise&lt;/em&gt; over Lake Michigan from Chicago.&lt;/p&gt;&#xA;&lt;p&gt;The most common form of such a green flash involves a setting where cooler air is atop a warmer surface, which produces an &lt;a href=&quot;https://www.eoas.ubc.ca/courses/atsc113/sailing/met_concepts/10-met-local-conditions/10f-optical-phenomena/&quot; rel=&quot;nofollow noreferrer&quot;&gt;inferior mirage&lt;/a&gt; like we commonly see in a desert or on a roadway.  In this case, however, we are basically looking along the reflection plane where the mirage produces magnification and therefore makes the green flash visible.&lt;/p&gt;&#xA;&lt;p&gt;The reader can learn more about green flashes &lt;a href=&quot;https://aty.sdsu.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2020-08-03T00:02:31.507" LastActivityDate="2020-08-03T00:02:31.507" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20017" PostTypeId="2" ParentId="19993" CreationDate="2020-08-03T02:14:04.953" Score="2" Body="&lt;p&gt;Unfortunately, what you want may not be actually available. &lt;a href=&quot;https://www.weather.gov/media/coop/Snow_Measurement_Guidelines-2014.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;It is standard to make measurements of snow every 24 hours.&lt;/a&gt; This is because it is well known that &lt;a href=&quot;http://www.lakecountyskywarn.org/education/guides/snowfall.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;frequent observations of snowfall will exceed the total accumulated snowfall.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The total accumulation of snow is not equal to the sum of the accumulated rate of the integral. That is, &lt;span class=&quot;math-container&quot;&gt;$$\Delta S \ne\int_{t_0}^{t_1}Rdt$$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$\Delta S$&lt;/span&gt; is the change in snow depth and &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; is the snowfall rate. This is because compaction and melting both occur, changing snow depth.&lt;/p&gt;&#xA;&lt;p&gt;That being said, you can make an approximation using daily snowfall depth observations. In the U.S., there are two systems that spring to mind. The first is the &lt;a href=&quot;https://mesonet.agron.iastate.edu/COOP/&quot; rel=&quot;nofollow noreferrer&quot;&gt;U.S. Cooperative Observation Program&lt;/a&gt;, which uses the standard in-situ observations of snow depth. The second is the NOHRSC, which has an analysis product (use &lt;a href=&quot;https://www.nohrsc.noaa.gov/snowfall/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this link&lt;/a&gt; for archived numerical data or &lt;a href=&quot;https://www.nohrsc.noaa.gov/interactive/html/map.html?var=snowfall_24_h&amp;amp;snap=1&amp;amp;bgvar=dem&amp;amp;shdvar=shading&amp;amp;o9=1&amp;amp;o13=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;this link&lt;/a&gt; for a graphical product).&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2020-08-03T19:52:08.447" LastActivityDate="2020-08-03T19:52:08.447" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20018" PostTypeId="1" CreationDate="2020-08-03T02:16:34.433" Score="1" ViewCount="24" Body="&lt;p&gt;I have been trying to find literature values for reflectance of soybean for different dates along the growing season (I am specifically interested in 30, 60 and ~120 days after planting - so the V3/V4 stage, R3/R4 stage and R8 stage) but all the spectral response graphs (there's only graphs - I haven't seen a table) that show up in my literature search have &amp;quot;Average Spectral Response&amp;quot; and no date indicated. There is a &lt;a href=&quot;https://ntrs.nasa.gov/search.jsp?R=19860003273&quot; rel=&quot;nofollow noreferrer&quot;&gt;1984 dataset&lt;/a&gt; on the NASA website which has measurement dates mentioned - but no mention of planting date, and the reflectance data doesn't mention the measurement dates either.&lt;/p&gt;&#xA;&lt;p&gt;Is there a paper or some other resource where I could find such data? I should add that this is for remote-sensing work, hence why I want data for different dates - I want the presence of soil to be accounted for in the reflectances reported.&lt;/p&gt;&#xA;" OwnerUserId="20828" LastActivityDate="2020-08-03T02:16:34.433" Title="Where can I find canopy reflectance data for crops (soybean in particular) for different dates across the growing season" Tags="|remote-sensing|agriculture|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20019" PostTypeId="1" AcceptedAnswerId="20038" CreationDate="2020-08-04T16:56:54.203" Score="2" ViewCount="117" Body="&lt;p&gt;Would you please let me know if the following is accurate as an answer to the question:&lt;/p&gt;&#xA;&lt;p&gt;Suppose we have sensors which measure the volumetric soil water content of a soil layer for a long period (more than 6 months). Could I attribute the maximum (percentage) in this dataset to the saturation point?&lt;/p&gt;&#xA;&lt;p&gt;I understand that we do need to have a lengthy rainfall event to have a saturated soil condition. How long the event should be so that the above proposal works?&lt;/p&gt;&#xA;&lt;p&gt;And if there is any other way that I can get to the saturation point of a soil layer from the volumetric soil water content data/sensors, please let me know.&lt;/p&gt;&#xA;&lt;p&gt;Mostly focused on the topsoil and preferably only using the dataset.&lt;/p&gt;&#xA;&lt;p&gt;Thank you all.&lt;/p&gt;&#xA;" OwnerUserId="20807" LastEditorUserId="20807" LastEditDate="2020-08-06T19:58:56.937" LastActivityDate="2020-08-06T19:58:56.937" Title="How to obtain the saturation point of a soil layer from the volumetric soil water content data?" Tags="|hydrology|earth-observation|hydrogeology|soil-science|soil-moisture|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20020" PostTypeId="2" ParentId="19995" CreationDate="2020-08-04T17:22:32.833" Score="-2" Body="&lt;p&gt;The current popular view is that the total quantity of water on the planet is a constant value. This appears to be an &lt;em&gt;assumption&lt;/em&gt;.  There has not been enough study and information published on this subject to prove or disprove that burning hydrocarbons fuels can contribute to rising sea levels.&lt;/p&gt;&#xA;&lt;p&gt;Thank you to those who have provided comments and an answer. This has been a good learning experience.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Water_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;Water Cycle&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.applet-magic.com/watervapor01.htm#:%7E:text=Therefore%20one%20gallon%20of%20gasoline,a%20volume%20of%201.033%20gallons.&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Role of Anthropogenic&#xA;Water Vapor in Earth's Climate&lt;/a&gt; provides a &lt;em&gt;review&lt;/em&gt; of the positions taken by various organization concerned with climate about the role of water vapor in the Earth's climate system. I encourage you to review / read this yourself.&lt;/p&gt;&#xA;&lt;p&gt;Some key items from that review to consider:&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;the burning of one gallon of gasoline produces 3,914.6 grams of water. This is equal to 8.6 pounds of water, which has a volume of 1.033 gallons&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;There was about 22 trillion cubic feet of natural gas burned in the United States in 2006...so the water vapor proburninduced (sic) in a year from burning natural gas is 263.4 billion gallons of water. This is per year; per day the figure is 722.4 million gallons.&amp;quot;&lt;/p&gt;&#xA;" OwnerUserId="20806" LastActivityDate="2020-08-04T17:22:32.833" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20021" PostTypeId="1" CreationDate="2020-08-04T17:26:38.630" Score="35" ViewCount="11492" Body="&lt;p&gt;Do you know any example of a river that does not flow into sea or lake? For example, if water rises from the underground spring and forms a river but water vaporises in hot climate before it reaches any larger body of water. Or if there is a valley with very moderate precipitation and many little creeks flow out of the valley and the water from them is absorbed by the soil.&lt;/p&gt;&#xA;" OwnerUserId="20833" LastActivityDate="2024-04-03T09:18:44.027" Title="Is there any river that does not discharge into larger body of water?" Tags="|hydrology|geography|rivers|hydrogeology|" AnswerCount="9" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="20022" PostTypeId="2" ParentId="20021" CreationDate="2020-08-04T18:25:28.770" Score="26" Body="&lt;p&gt;There are rivers that don't flow into seas or lakes if you consider influent rivers. Which are rivers that loose water to the ground (seeps into aquifers). For example &amp;quot;big lost river&amp;quot; of Idaho, which feeds into the Snake river aquifer.&lt;/p&gt;&#xA;&lt;p&gt;In regards to evaporation, it depends on what you consider a river. Because water flowing through a tiny little rill or gully wouldn't necessarily reach a lake. But do you consider that a river? Wadis or ramblas are river beds in arid or semiarid areas, thus, dry. But when it does rain, they normally reach the sea. But if it rains a little bit, then it wouldn't reach.&lt;/p&gt;&#xA;&lt;p&gt;From Wikipedia's &lt;a href=&quot;https://en.wikipedia.org/wiki/Lost_streams_of_Idaho&quot; rel=&quot;noreferrer&quot;&gt;Lost streams of Idaho&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;There are two rivers in Idaho named &amp;quot;Lost&amp;quot;, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Big_Lost_River&quot; rel=&quot;noreferrer&quot;&gt;Big Lost River&lt;/a&gt; and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Little_Lost_River&quot; rel=&quot;noreferrer&quot;&gt;Little Lost River&lt;/a&gt;. They are often considered separate streams, but both flow into the same depression and become subterranean, feeding the Snake River Aquifer. The rivers are located in Custer County and Butte County, in Idaho in the United States. Via the aquifer and numerous springs, they are tributaries of the Snake River.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="20834" LastEditorUserId="6031" LastEditDate="2020-08-05T05:09:43.257" LastActivityDate="2020-08-05T05:09:43.257" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20023" PostTypeId="2" ParentId="20021" CreationDate="2020-08-04T19:12:33.873" Score="46" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Okavango_River&quot; rel=&quot;noreferrer&quot;&gt;Okavango River&lt;/a&gt; is a good example of this. It drains into a swampy delta in the middle of the Kalahari desert:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/7/74/A_view_down_into_the_Okavango_Delta.jpg/640px-A_view_down_into_the_Okavango_Delta.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&#xA;The Okavango Delta, &lt;a href=&quot;https://creativecommons.org/licenses/by/2.0/deed.en&quot; rel=&quot;noreferrer&quot;&gt;CC BY&lt;/a&gt; Justin Hall.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2020-08-05T07:10:34.583" LastActivityDate="2020-08-05T07:10:34.583" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20024" PostTypeId="2" ParentId="20021" CreationDate="2020-08-04T20:18:07.820" Score="36" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Colorado_River&quot; rel=&quot;noreferrer&quot;&gt;Colorado River&lt;/a&gt; frequently fails to reach the Gulf of California, mostly due to diversion to agricultural and metropolitan uses upstream.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://blog.nationalgeographic.org/2014/05/19/a-sacred-reunion-the-colorado-river-returns-to-the-sea/#:%7E:text=the%20salty%20sea.-,It%20is%20the%20first%20time%20in%20sixteen%20years%20that%20the,reached%20its%20final%2C%20natural%20destination.&quot; rel=&quot;noreferrer&quot;&gt;This National Geographic post from 2014&lt;/a&gt; elaborates on the Colorado River reaching the sea for the first time in 16 years:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This reunion between river and sea is due to an agreement between&#xA;Mexico and the United States, known as Minute 319, to advance the&#xA;restoration of the Colorado Delta by releasing a pulse flow and&#xA;sustaining base flows in a five-year experiment.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/QzEg9.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QzEg9.jpg&quot; alt=&quot;The river mingles with the tidal channels of the estuary. Photo credit: Francisco Zamora, Sonoran Institute, with aerial support from LightHawk.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7314" LastEditorUserId="7314" LastEditDate="2020-08-05T14:37:54.237" LastActivityDate="2020-08-05T14:37:54.237" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20026" PostTypeId="2" ParentId="20021" CreationDate="2020-08-05T12:14:14.573" Score="28" Body="&lt;p&gt;The concepts you are looking for are two categories of drainage basins, endhoreic basins and cryptorheic basins.&lt;/p&gt;&#xA;&lt;p&gt;Endhoreic basins are drainage basins that do not drain to the oceans, either above ground or below. The rivers in an endhoreic basin flow toward a local low spot. In some places these low spots are permanently covered by water. Examples includes the Caspian Sea, the Dead Sea, and the Great Salt Lake. I suspect you would not count these rivers as the bodies of water into which they flow are permanent.&lt;/p&gt;&#xA;&lt;p&gt;But in other endhoreic basin the bodies of water are only occasionally wet. These dry lake beds become short-lived lakes in the rare case of exceptionally high precipitation. The Amargosa River, for example, occasionally experiences high flow rates and turns the normally bone dry Badwater Basin in Death Valley in California into a lake. This lake doesn't last very long at all.&lt;/p&gt;&#xA;&lt;p&gt;Another example is Lake Eyre in South Australia. Lake Eyre is dry most of the time, but occasionally it does get visibly wet, and very rarely it gets quite wet and then takes a couple of years to dry. There are several rivers in the Lake Eyre Basin that occasionally feed the lake. One of them is the Fincke River, one of oldest rivers in the world. The Fincke River is typically dry. On the rare occasion when water runs through it, the flowing water usually sink into the ground before going very far. But every once in a while, sufficient rainfall falls to enable the Fincke to flow all the way to Lake Eyre.&lt;/p&gt;&#xA;&lt;p&gt;Yet another example is Okavango River, as mentioned by Jean-Marie Prival. In the aftermath of the wet season, the Okavango Delta drains into the Thamalakane River, which in turn drains into the Boteti River, which in turn drains into the Ntwetwe Pan. The Ntwetwe Pan is typically a very dry and nearly lifeless salt pan. The Boteti usually dries up before it reaches the Ntwetwe Pan.&lt;/p&gt;&#xA;&lt;p&gt;There are many other examples of endhoreic basins in the world where the lowest spot is a salt pan that is only occasionally covered with water.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;The other category I mentioned are cryptorheic basins. These are typically associated with karst. Karst topography oftentimes results where the surface rock is made of easily dissolved limestone. Much of the drainage in cryptorheic basins is hidden because it occurs underground, hence the &lt;em&gt;crypto&lt;/em&gt; prefix.&lt;/p&gt;&#xA;&lt;p&gt;The upper Danube provides a nice example. It eventually runs dry almost half of the year because its waters sink into the Danube Sinkhole. This sinking happens all year round, but at times the above ground flow remains sufficient to keep the upper Danube flowing. The underground flow eventually merges to form the Radolfzeller Aach, which is a tributary of the Rhine. The underground flow drains to the North Sea while the above ground flow drains to the Black Sea.&lt;/p&gt;&#xA;&lt;p&gt;There are many other losing streams (streams that lose rather than gain water) in the world. Another example is the Lost River in West Virginia. It disappears under Sandy Ridge and reemerges a couple of miles (three kilometers) away on the other side of the mountain as the headwaters of the Cacapon River. There are several other streams named Lost River in the US.&lt;/p&gt;&#xA;&lt;p&gt;Eastern Australia also has many disappearing rivers. The Great Artesian Basin is a large cryptorheic basin that ultimately empties to the ocean. Some of the rivers in eastern Australia disappear, not because of evaporation, but because their waters sink to replenish the Great Artesian Basin.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2020-08-05T12:21:43.557" LastActivityDate="2020-08-05T12:21:43.557" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20027" PostTypeId="1" CreationDate="2020-08-05T13:34:44.887" Score="1" ViewCount="37" Body="&lt;p&gt;I had this albedo conversion written down:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\alpha = 0.53\alpha_{VIS}+0.47\alpha_{NIR}$$&lt;/span&gt;&#xA;I had on my notes that this equation was form Collins et al (2002).&#xA;However, I cannot find where this came from at all.&#xA;Hope you guys can help me out!&lt;/p&gt;&#xA;" OwnerUserId="20844" LastEditorUserId="20844" LastEditDate="2020-08-06T13:42:46.617" LastActivityDate="2020-08-06T13:42:46.617" Title="Broadband Albedo Conversion Scheme" Tags="|geophysics|data-analysis|reference-request|research|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20029" PostTypeId="2" ParentId="20021" CreationDate="2020-08-05T17:01:12.147" Score="5" Body="&lt;p&gt;The Luni River of India does not meet any sea, ocean, lake, or any other body of water. Most Indian rivers meet larger rivers or flow into the Bay of Bengal or the Arabian sea. This river starts at an elevation of 772 meters from the Naga Hills of Aravalli in the Ajmer district of Rajasthan. The distance covers about 495 km, and the river meets its end in Barine. The water from the river drains on a shallow bed, leading to its termination, without flowing into any water body. The hot temperature and lack of rainfall is the reason for the supply of the voluminous water. The river is shallow enough to evaporate at its mouth, and the water turns saline because of the salt rich surface in Barmer. It is also very strange because some parts of the river resembles a lake and an ocean with waves.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/d4med.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/d4med.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20848" LastEditorUserId="18932" LastEditDate="2020-08-07T13:10:10.440" LastActivityDate="2020-08-07T13:10:10.440" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20030" PostTypeId="2" ParentId="12454" CreationDate="2020-08-05T17:45:33.763" Score="2" Body="&lt;p&gt;Pretty much, because the joining of the Americas caused a shift in the circulation of the oceans. Because before, there was no antarctic circumpolar current (ACC), but there was a current (maybe more) going north to south, distributing heat to the Antarctic. The closing of the isthmus caused that current to disappear, and create the ACC and the Weddel current. Thus making the Antarctic cold.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.whoi.edu/oceanus/feature/how-the-isthmus-of-panama-put-ice-in-the-arctic/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.whoi.edu/oceanus/feature/how-the-isthmus-of-panama-put-ice-in-the-arctic/&lt;/a&gt; (it's old this article but still..)&lt;/p&gt;&#xA;" OwnerUserId="20834" LastActivityDate="2020-08-05T17:45:33.763" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20031" PostTypeId="2" ParentId="20021" CreationDate="2020-08-05T17:46:19.937" Score="8" Body="&lt;p&gt;Just locally to me, there are the Carson and Humboldt rivers, which drain into sinks of those names - the &lt;a href=&quot;https://en.wikipedia.org/wiki/Carson_Sink&quot; rel=&quot;noreferrer&quot;&gt;Carson Sink&lt;/a&gt; and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Humboldt_Sink&quot; rel=&quot;noreferrer&quot;&gt;Humboldt Sink&lt;/a&gt;. There's also the &lt;a href=&quot;https://en.wikipedia.org/wiki/Quinn_River&quot; rel=&quot;noreferrer&quot;&gt;Quinn River&lt;/a&gt;, which drains into the Black Rock desert when it has water in it, which it doesn't always.&lt;/p&gt;&#xA;&lt;p&gt;There are many smaller rivers &amp;amp; creeks that do this.  For instance, a lot of smaller creeks on the east slope of the Sierra will (seasonally) disappear when they reach the talus slopes at the foot of the mountains.&lt;/p&gt;&#xA;" OwnerUserId="1401" LastEditorUserId="18932" LastEditDate="2020-08-06T20:32:00.580" LastActivityDate="2020-08-06T20:32:00.580" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20032" PostTypeId="2" ParentId="20021" CreationDate="2020-08-05T17:53:38.647" Score="6" Body="&lt;p&gt;A must-to-mention is &lt;a href=&quot;https://en.wikipedia.org/wiki/Amu_Darya&quot; rel=&quot;noreferrer&quot;&gt;Amu Darya&lt;/a&gt;. It was once flowing to Aral sea, but since ~1950s the water has been used for irrigation, and now its waters do not reach the sea. (And as a result, there it little that remains of the sea.)&lt;/p&gt;&#xA;" OwnerUserId="20849" LastActivityDate="2020-08-05T17:53:38.647" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20033" PostTypeId="1" CreationDate="2020-08-05T19:30:45.313" Score="1" ViewCount="49" Body="&lt;p&gt;I know there were settlements in South Georgia in the past, but they were all abandoned. Is there any environmental reason why a new settlement could not be made? Especially with global warming, the climate has gotten warmer.&lt;/p&gt;&#xA;" OwnerUserId="20850" LastActivityDate="2020-08-05T19:30:45.313" Title="South Georgia Island and Settlement" Tags="|climate-change|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20034" PostTypeId="2" ParentId="12454" CreationDate="2020-08-05T21:16:42.493" Score="4" Body="&lt;p&gt;The closing of the Isthmus of Panama alone did not trigger the beginning of the Ice Age, but it is a potentially decisive step on the way of ice shield build up in the north.&lt;/p&gt;&#xA;&lt;p&gt;The development that leads to the current Ice Age, per definition a phase in earth's history were polar and continental ice shield build up, starts much earlier. Cooling began after a greenhouse phase already 60 million years ago at the end of the Cretaceous, possibly because of &lt;a href=&quot;https://www.nature.com/articles/ncomms5194&quot; rel=&quot;nofollow noreferrer&quot;&gt;declining atmospheric CO2 levels&lt;/a&gt;. Intense volcanism (flood basalts) and the Chicxulub impact surely have contributed to peak cooling at that time.&lt;/p&gt;&#xA;&lt;p&gt;During the late Paleogene and Neogene, Around ~40 - 30 Million years ago Antarctica and Australia separated and the Drake Passage opened, enabling an Antarctic circumpolar current (ACC) that isolated Antarctica from global circulation. Though the role of the current is &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0967064507001786&quot; rel=&quot;nofollow noreferrer&quot;&gt;debated&lt;/a&gt;, it &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0012821X05002712&quot; rel=&quot;nofollow noreferrer&quot;&gt;coincides at least partly&lt;/a&gt; with ice shield buildup in Antarctica, but declining CO2 may have played an equal or &lt;a href=&quot;https://www.nature.com/articles/nature01290&quot; rel=&quot;nofollow noreferrer&quot;&gt;even bigger role&lt;/a&gt;. The &lt;a href=&quot;https://link.springer.com/content/pdf/10.1007%2Fs11434-013-5987-8.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;uplift of the Tibetian plateau&lt;/a&gt; may have contributed to cooling by chaning continental circulation patterns. Reason for the CO2 carbon decline in the late Paleogene/early Neogene may be &lt;a href=&quot;https://pubs.geoscienceworld.org/gsa/geology/article/45/8/763/350516/Silicate-weathering-volcanic-degassing-and-the&quot; rel=&quot;nofollow noreferrer&quot;&gt;increased silicate weathering&lt;/a&gt; in the course of the Himalayas and the Alpine orogeny.&lt;/p&gt;&#xA;&lt;p&gt;So, when the Isthmus of Panama closed (&lt;a href=&quot;https://www.nature.com/articles/31447&quot; rel=&quot;nofollow noreferrer&quot;&gt;exact&lt;/a&gt; &lt;a href=&quot;https://advances.sciencemag.org/content/2/8/e1600883&quot; rel=&quot;nofollow noreferrer&quot;&gt;date&lt;/a&gt; &lt;a href=&quot;https://advances.sciencemag.org/content/3/6/e1602321&quot; rel=&quot;nofollow noreferrer&quot;&gt;debated&lt;/a&gt;), it was already pretty cold compared to the Cretaceous and an ice shield covered Antarctica. The closing is hypothesized to have steered the gulf stream farther north, enabling the &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0012821X05004048&quot; rel=&quot;nofollow noreferrer&quot;&gt;transport of moisture and warm air&lt;/a&gt; to the north and thus ice shield build up there.&lt;/p&gt;&#xA;&lt;p&gt;We also should keep in mind generally ice shield buildup has a feedback in itself by rising the albedo, thus reflecting more energy back to space.&lt;/p&gt;&#xA;&lt;p&gt;It is a complicated path to the current Ice Age with a lot of facets, starting in the late Cretaceous.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-08-06T08:49:23.637" LastActivityDate="2020-08-06T08:49:23.637" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20035" PostTypeId="2" ParentId="20021" CreationDate="2020-08-05T22:42:33.897" Score="1" Body="&lt;p&gt;Does a river emptying into another river count?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Roe_River&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Roe_River&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Roe River runs from Giant Springs to the Missouri River near Great Falls, Montana, United States. The Roe River is only 201 feet (61 m) long at its longest constant point&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="20851" LastActivityDate="2020-08-05T22:42:33.897" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20036" PostTypeId="1" CreationDate="2020-08-06T01:20:49.093" Score="1" ViewCount="256" Body="&lt;p&gt;This is somewhat of a follow up to some interesting discussion &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4276/nuclear-testing-and-the-anthropocene-a-chemostratigraphic-link/4278#4278&quot;&gt;here&lt;/a&gt; about using synthetic radioisotopes to define the start of the anthropocene. It is also sort of related to a question asked &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9061/could-evidence-of-a-signal-from-an-exocivilization-be-found-in-the-geologic-reco&quot;&gt;here&lt;/a&gt;, but with some additional thought put into it that I hope merits its own response. My question is simply:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Has there been any serious thought put into the search for ancient industrialised civilisations that would generate a signal comparable to human civilisation in the sediment record?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;As a complete layman, it seems at least possible that paleontological (archaeological?) record may be incomplete enough that we have completely missed or misinterpreted evidence of an ancient civilisation. I would imagine that not a lot of human structures/artifacts would survive weathering over millions of years. It would stand to reason that there would not be a whole lot left from this hypothetical ancient civilisation.&lt;/p&gt;&#xA;&lt;p&gt;Given the discussion in the question I linked above, what &lt;em&gt;would&lt;/em&gt; last a long time would be evidence of our atmospheric nuclear explosions/accidents. One could imagine that isotopes that are not normally naturally present, such as long lived fission products like I-129, unused nuclear fuel like U-235, or their decay products such as U-236 from the alpha decay of Pu-240 could be present in a thin layer in the sediment record. In addition, one could also look for a spike of naturally present isotopes that would result from the incorporation of radioisotopes by living organisms (for example spikes in Zr-90 from the incorporation of Sr-90 replacing calcium in foraminifera). Given the types of isotopes present, one might even be able to guess at their origin (e.g. nuclear detonation, reactor accident, or breach of waste storage)&lt;/p&gt;&#xA;&lt;p&gt;Moving away from the radioisotopes, this hypothetical civilisation might also have used fossil fuels, resulting in global warming similar to what we see today. Intriguingly, from my reading it seems that there are events that produced abrupt warming (e.g. Paleocene–Eocene Thermal Maximum) whose cause and/or trigger is poorly understood, though I won't speculate too much about this as it's not my area.&lt;/p&gt;&#xA;&lt;p&gt;I think there are probably other signals that one could look for, for example evidence of industrial pollution or agriculture. However, I think these might be trickier to see than the radioisotope signal, as they are chemical and therefore might be difficult to distinguish from a sudden natural process. Nevertheless, it seems like the combination several of these types of signals with an abrupt onset and end in the sediment records would be pretty convincing evidence for an ancient civilisation. Perhaps more exciting, it seems like these could be tested with existing methods or even existing samples.&lt;/p&gt;&#xA;&lt;p&gt;I don't want to come off as a total crackpot, but I hope that this has shown why this seem like an interesting and accessible line of inquiry to a non-geologist, even if I don't think the hypothesis of an ancient civilisation is particularly likely. What I will jokingly call SATI (Search for Ancient Terrestial Intelligence) seems to me equally significant to the much more well known SETI, and is much more likely to give some kind of result, whether positive or negative. Genuinely curious if this sort of thing has been seriously thought about and researched, or if there is something that I'm not understanding that would make this not as clear-cut as I'm making it out to be.&lt;/p&gt;&#xA;" OwnerUserId="20852" LastActivityDate="2022-11-03T17:29:30.460" Title="Have we looked for human-like signals in the geological record?" Tags="|sedimentology|paleoclimatology|stratigraphy|radioactivity|" AnswerCount="2" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="20037" PostTypeId="2" ParentId="20021" CreationDate="2020-08-06T05:05:19.580" Score="2" Body="&lt;p&gt;Locally to me, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Little_Stour&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nailbourne&lt;/a&gt; rises at a spring in the small town of Lyminge, in the Kent Downs, and then sinks back into the ground shortly after passing through the village of Elham (except in a very wet winter when groundwater levels rise enough for it to stay above ground). You might choose to disqualify it because it does resurface lower down the watercourse and eventually joins the River Stour which drains into the sea.&lt;/p&gt;&#xA;" OwnerUserId="2577" LastActivityDate="2020-08-06T05:05:19.580" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20038" PostTypeId="2" ParentId="20019" CreationDate="2020-08-06T07:17:50.610" Score="4" Body="&lt;p&gt;I assume you mean sensors that measure volumetric soil &lt;strong&gt;water&lt;/strong&gt; content. The answer will depend on the amount of precipitation and the permeability of the soil. Soils don't reach full saturation in some climates - especially coarse texture soils. I would say that if the soil water content reaches a maximum value that persists for a period of time after large rainfalls (giving a flat top) and ideally reaches the same maximum level during multiple wetting-drying cycles that it is reasonable to infer that is the saturation value.&lt;/p&gt;&#xA;&lt;p&gt;Ideally you would collect undisturbed soil samples of known volume (e.g in by driving a cylinder into the soil (gently as possible) to determine the pore volume and saturated water content.&lt;/p&gt;&#xA;&lt;p&gt;Also be aware that many soil moisture sensors give readings that are dependent on soil properties and are not linear up to 100% saturation so they may not give good values at high water contents. It is best to calibrate those types on your soils.&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2020-08-06T07:17:50.610" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20039" PostTypeId="2" ParentId="19400" CreationDate="2020-08-06T12:57:02.137" Score="1" Body="&lt;p&gt;Well, in short, it's mainly continental, (oceanic-continental convergence).&lt;/p&gt;&#xA;&lt;p&gt;But in regards to the &amp;quot;type of plate&amp;quot; that the Sunda plate is, is minor plate or tertiary plate. Meaning it's not very big etc. Because 1 tectonic plate can have both oceanic or continental crust. Tectonic plate and crust are slightly different concepts. So, The Sunda plate is mainly comprised of continental crust. There might be a bit of oceanic crust, but less.&lt;/p&gt;&#xA;&lt;p&gt;Map of oceanic crust on earth: &lt;a href=&quot;https://www.ngdc.noaa.gov/mgg/ocean_age/data/2008/ngdc-generated_images/whole_world/2008_age_of_oceans_plates.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ngdc.noaa.gov/mgg/ocean_age/data/2008/ngdc-generated_images/whole_world/2008_age_of_oceans_plates.jpg&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20834" LastActivityDate="2020-08-06T12:57:02.137" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20040" PostTypeId="1" CreationDate="2020-08-06T13:36:06.563" Score="1" ViewCount="1700" Body="&lt;p&gt;According to wikipedia &amp;quot;The Phalgu or Falgu, a river that flows past Gaya, India in the Indian state of Bihar, is a sacred river for Hindus and Buddhists. Lord Vishnu's Temple Vishnupad Mandir is situated on the bank of Phalgu river.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;My question is &amp;quot;Why is this river subterranean?&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;I know that according to Hindu mythology it is believed that &amp;quot;During their exile, Rama and Sita decided to rest for a while on the Falgu's sandy banks. When it was time for pind-daan, the offering of food to ancestors to enable them to have peace, Rama went to secure the necessary provisions while Sita waited on the banks. While he was still away, Rama's ancestors appeared in front of her and requested that the ceremony be conducted without delay. Rather than wait for the offerings of food, she performed the ceremony offering sand to the ancestors instead, thereby granting them salvation.&lt;/p&gt;&#xA;&lt;p&gt;Fearful that her husband would not believe her, she asked the sacrificial fire, a cow, the Falgu, a brahman and a tree to stand witness for her act. Sadly, when Rama arrived on the scene and questioned the witnesses, they all turned false. The hope of a second round of offerings if Rama conducted the ceremony one more time, prompted all the witnesses other than the tree to say that Sita was lying. Enraged, she cursed all the witnesses but the faithful tree. Thus, the Falgu was condemned to run below the ground hiding her head in shame, for all time.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;But I want to know what's the scientific geological reason behind it.&lt;/p&gt;&#xA;&lt;p&gt;Thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="20857" LastActivityDate="2020-08-06T13:36:06.563" Title="What is the scientific reason for Falgu river being subterranean?" Tags="|geology|hydrology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20041" PostTypeId="2" ParentId="6495" CreationDate="2020-08-06T13:55:14.110" Score="1" Body="&lt;p&gt;I'm digging up this question, because since it was asked there were &lt;a href=&quot;http://pluto.jhuapl.edu/Mission/Publications.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;many publications&lt;/a&gt; about New Horizons findings, proposing at least two other processes (not mentioned in the previous answer) for resurfacing Pluto.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Sublimation&lt;/strong&gt;. &lt;a href=&quot;https://doi.org/10.1016/j.icarus.2016.08.025&quot; rel=&quot;nofollow noreferrer&quot;&gt;Moore et al.&lt;/a&gt; (2017) showed how sublimation of nitrogen ice could lead to the formation of the pit fields observed in some icy plains. This is somewhat similar to the formation of &lt;a href=&quot;https://en.wikipedia.org/wiki/Penitente_(snow_formation)&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;penitentes&lt;/em&gt;&lt;/a&gt; on Earth.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Dunes&lt;/strong&gt;. Although the previous study states that &amp;quot;there are no unambiguous aeolian landforms (e.g., dunes) observed on Pluto, which is consistent with either a lack of sand sized particles, and/or surface winds [...] capable of transporting them&amp;quot;, &lt;a href=&quot;https://doi.org/10.1126/science.aao2975&quot; rel=&quot;nofollow noreferrer&quot;&gt;Telfer et al.&lt;/a&gt; (2017) think otherwise. They interpreted some features as methane ice dunes. Sublimation actually provides a nice mechanism for lofting the ice grains.&lt;/p&gt;&#xA;&lt;p&gt;These two precesses do not need internal heat to explain the recycling of the surface, but you could say that Pluto is at least &amp;quot;glaciologically&amp;quot; active!&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-08-06T13:55:14.110" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20042" PostTypeId="2" ParentId="20036" CreationDate="2020-08-06T16:22:48.340" Score="1" Body="&lt;p&gt;Any nuclear activity would be visible in the changes of the isotope ratios far longer than the existence of our Universe. Nothing was found until now, &lt;a href=&quot;https://en.wikipedia.org/wiki/Natural_nuclear_fission_reactor&quot; rel=&quot;nofollow noreferrer&quot;&gt;except one in Gabon&lt;/a&gt;. It was natural phenomenon: at the time, 2billion years ago, there was far more &lt;span class=&quot;math-container&quot;&gt;${}^{235} \rm U$&lt;/span&gt; and the ground water could moderate uranium ore, if it was enough rich.&lt;/p&gt;&#xA;&lt;p&gt;Except that, nothing was found until now.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;Offtopic, but the case is same for radio signals. If any Earth-like civilization would exist in 100 light years away, we would see their radio signals. There is radio silence.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="6016" LastActivityDate="2020-08-06T16:22:48.340" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20043" PostTypeId="1" AcceptedAnswerId="20056" CreationDate="2020-08-06T23:21:40.473" Score="3" ViewCount="238" Body="&lt;p&gt;I link below to questions on another kind of Mars pulse) Phys.org's &lt;a href=&quot;https://phys.org/news/2020-08-nasa-maven-martian-night-sky.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA's Maven observes Martian night sky pulsing in ultraviolet light&lt;/a&gt; links to the new paper &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/2019JA027318&quot; rel=&quot;nofollow noreferrer&quot;&gt;Imaging of Martian Circulation Patterns and Atmospheric Tides Through MAVEN/IUVS Nightglow Observations&lt;/a&gt; in Journal of Geophysical Research: Space Physics.&lt;/p&gt;&#xA;&lt;p&gt;This seems to be related to long period of waves in Mars' atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;Question:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Is it possible to explain in simple terms what makes these waves happen?&lt;/li&gt;&#xA;&lt;li&gt;Is a analogous or at least related &lt;strong&gt;wave&lt;/strong&gt; phenomenon detectable in Earth's atmosphere?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;A different (and currently unanswered) question about a different periodic behavior in Mars' atmosphere:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/19325/6031&quot;&gt;How could the solar wind cause strange magnetic pulses on Mars at midnight?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2022-05-21T22:27:51.657" LastActivityDate="2022-05-21T22:27:51.657" Title="Now Mars is pulsing 3 times per night in the UV, can anyone explain these waves in simple terms? Do these waves have analogies on Earth?" Tags="|planetary-science|atmospheric-chemistry|satellites|solar-terrestrial-physics|upper-atmosphere|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20044" PostTypeId="2" ParentId="20043" CreationDate="2020-08-07T01:01:27.670" Score="3" Body="&lt;p&gt;The Martian nightglow comes from molecules in the atmosphere that react with solar radiation, carry it over to the night side, and give off the energy they gained as ultraviolet light as they free-form stable compounds.  From &lt;a href=&quot;https://www.nasa.gov/press-release/goddard/2020/mars-nightglow&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nasa.gov/press-release/goddard/2020/mars-nightglow&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/oGe69.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The diagram explains the cause of Mars’ glowing nightside atmosphere. On Mars’ dayside, molecules are torn apart by energetic solar photons. Global circulation patterns carry the atomic fragments to the nightside, where downward winds increase the reaction rate for the atoms to reform molecules. The downwards winds occur near the poles at some seasons and in the equatorial regions at others. The new molecules hold extra energy which they emit as ultraviolet light.&#xA;Credits: NASA/MAVEN/Goddard Space Flight Center/CU/LASP&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The Martian nightglow has been used to trace atmospheric circulation on Mars.&lt;/p&gt;&#xA;&lt;p&gt;As for a similar phenomenon on Earth, and for that matter on planets generally, the above NASA reference goes on to say:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Many planets including Earth have nightglow, but MAVEN is the first mission to collect so many images of another planet’s nightglow.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2020-08-07T01:01:27.670" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20045" PostTypeId="1" AcceptedAnswerId="20046" CreationDate="2020-08-07T09:25:49.427" Score="3" ViewCount="960" Body="&lt;p&gt;I have done a bit of research on this topic already and the easiest way seems to be the &lt;a href=&quot;https://en.wikipedia.org/wiki/Eratosthenes#Earth%27s_circumference&quot; rel=&quot;nofollow noreferrer&quot;&gt;experiment by Eratosthenes&lt;/a&gt;. We pick two locations on the same latitude (of which we know the distance) and then measure the length of the shadow of a vertical stick at solar noon to get two angles. We can then figure out the difference between these angles and plug it into the formula:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;\begin{align}&#xA;\frac{\text{angle}}{360°}&amp;amp;=\frac{\text{distance}}{\text{circumference of the earth}}\\[3mm]&#xA;\text{circumference of the earth}&amp;amp;=\frac{360°}{\text{angle}}\times\text{distance}\\&#xA;\end{align}&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now I would like to do a similar experiment. My family has friends who live 1260km west (and a little south) from us. Is there a way for us take a measurement at the same time and calculate the circumference of the earth? Obviously the formula above does no longer apply since we never have the same solar noon.&lt;/p&gt;&#xA;" OwnerUserId="20865" LastActivityDate="2021-09-15T21:34:06.257" Title="Measuring the circumference of the earth - revisited" Tags="|measurements|earth-observation|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20046" PostTypeId="2" ParentId="20045" CreationDate="2020-08-07T10:03:34.587" Score="6" Body="&lt;p&gt;You can use the fact that the Earth's rotation period is known.  Then divide that period (use the solar day of 24 hrs 00 minutes instead of the sidereal day of 23 hrs 56 minutes) by the actual amount of time between your two solar noons and multiply the resulting factor by your 1260 km distance.&lt;/p&gt;&#xA;&lt;p&gt;The result is the circumference ... of your latitude circle.  To get the circumference of a great circle and thus the Earth, you need to divide the calculated number above by the cosine of your latitude.  To get the latitude perform your experiment on an equinox and measure the shadow angle at solar noon.&lt;/p&gt;&#xA;&lt;p&gt;Have fun, good luck!&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2020-08-07T10:03:34.587" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20047" PostTypeId="2" ParentId="19493" CreationDate="2020-08-07T15:31:15.327" Score="2" Body="&lt;p&gt;This study suggests that the effect on climate change will be neglible:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/s41558-020-0883-0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Forster et. al. (2020)&lt;/a&gt;: Current and future global climate impacts resulting from COVID-19&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;[...] As a result, we estimate that the direct effect of the pandemic-driven response will be negligible, with a cooling of around 0.01 ± 0.005 °C by 2030 compared to a baseline scenario that follows current national policies. [...]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In other words, if there are no changes to the economy, there will be no positive effect on climate change.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-08-07T16:04:29.760" LastActivityDate="2020-08-07T16:04:29.760" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20049" PostTypeId="1" CreationDate="2020-08-08T06:27:32.103" Score="1" ViewCount="41" Body="&lt;p&gt;The North Indian Ocean basin which consists of Bay of Bengal and Arabian Sea witnesses mainly two tropical cyclone seasons: pre-monsoon and post-monsoon.&#xA;My question is that what is it that causes the formation of tropical cyclones in this basin in post-monsoon season especially in the months of November and December. At that time of the year, sun's apparent position is near the Tropic of Capricorn in the southern hemisphere. Also the cyclones formed in this season are more destructive. What could be the reason behind this?&lt;/p&gt;&#xA;" OwnerUserId="18396" LastActivityDate="2020-08-08T06:27:32.103" Title="Tropical cyclones in North Indian Ocean in winter" Tags="|meteorology|tropical-cyclone|cyclone|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20051" PostTypeId="1" CreationDate="2020-08-09T17:17:37.490" Score="4" ViewCount="40" Body="&lt;p&gt;Do you know of any good animations, videos, or GIFs of petrification/permineralization? For some students verbal and written explanations don’t work, they don't always visualize well. So it’d be better to visually show minerals coming in &amp;amp; taking the place of organic molecules.&#xA;It would be great to see a representation of a fossil, and the zoom to a close up of a bone... then zoom in to show molecules. (They don't even have to be atomically correct. Just colorful and distinct.) Then show molecules of some other shape/color come in, and slowly displace the previous ones.&lt;/p&gt;&#xA;" OwnerUserId="20879" LastActivityDate="2020-08-09T17:17:37.490" Title="Looking for videos/GIFs of petrification/permineralization" Tags="|geology|minerals|fossils|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20052" PostTypeId="1" AcceptedAnswerId="20097" CreationDate="2020-08-10T13:40:39.647" Score="1" ViewCount="106" Body="&lt;p&gt;By some poorly understood series of events, I have managed to convince my 7 year old daughter that she wants to be a geologist when she's older. Of course I'm aware that this likely won't be the case, but I thought I'd try to seize on the moment and get her a book on geology.&lt;/p&gt;&#xA;&lt;p&gt;So I am looking for any recommendations for a children's book on geology, perhaps with facts/experiments about stuff that she can find in the garden/in her local area. We live in a reasonably urban part of the world (Surrey).&lt;/p&gt;&#xA;" OwnerUserId="20881" LastActivityDate="2020-08-22T09:47:40.123" Title="Book recommendation for 7 year old" Tags="|geology|teaching|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20053" PostTypeId="1" CreationDate="2020-08-10T22:05:41.673" Score="1" ViewCount="42" Body="&lt;p&gt;I've been looking at a lot of charts of Arctic Sea Ice lately, wondering when it will be gone, and whether the more extreme predictions are credible.&#xA;When scientists come up with a chart that points to around 2040 for sea ice going, do their models include events like the Siberian heat wave ?&#xA;Could such a thing render 2040 estimates useless ?&#xA;Thanks.&lt;/p&gt;&#xA;" OwnerUserId="11238" LastActivityDate="2020-08-10T22:05:41.673" Title="Are events like the Siberian heat wave factored into models of sea ice decline?" Tags="|climate-change|arctic|sea-ice|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="20054" PostTypeId="1" CreationDate="2020-08-11T00:31:09.123" Score="1" ViewCount="59" Body="&lt;p&gt;While driving behind the back side of an intense thunderstorm, I saw a lightning phenomenon I haven't seen before - just a bright blueish light at high speed, following an erratic path, just like the path a cloud-to-cloud bolt would trace. There was light ahead and before it for a short distance, trailing off in intensity.&lt;/p&gt;&#xA;&lt;p&gt;Does this fall into the category of ball lightning, or is it something else?&lt;/p&gt;&#xA;" OwnerUserId="13510" LastActivityDate="2020-08-11T00:31:09.123" Title="Lightning categorization of a high-speed &quot;ball&quot; of light" Tags="|meteorology|lightning|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20055" PostTypeId="1" CreationDate="2020-08-11T15:01:53.153" Score="7" ViewCount="88" Body="&lt;p&gt;Today, this XKCD popped up in a &lt;a href=&quot;https://chat.meta.stackexchange.com/rooms/89&quot;&gt;chatroom&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://xkcd.com/2344/&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://imgs.xkcd.com/comics/26_second_pulse.png&quot; alt=&quot;&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;em&gt;comic &lt;a href=&quot;https://creativecommons.org/licenses/by-nc/2.5/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CC BY-NC 2.5&lt;/a&gt; linked to the source&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;User &lt;a href=&quot;https://chat.meta.stackexchange.com/transcript/message/8512724#8512724&quot;&gt;Rob&lt;/a&gt; mentioned that (as usual with XKCD) this is based on the findings in a research paper.&lt;/p&gt;&#xA;&lt;p&gt;In &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2006GL027010&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source location of the 26 sec microseism from cross‐correlations of ambient seismic noise&lt;/a&gt; by N. M. Shapiro,  M. H. Ritzwoller  and G. D. Bensen the method to determine the location of microseism with a period of 26 seconds is described. While the hypocenter is indicated in latitude and longitude I couldn't find in that paper at what depth the microseism takes place.&lt;/p&gt;&#xA;&lt;p&gt;Living in a country known for its seismic activity I'm used to pinpoint accuracy:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://knmi.nl/nederland-nu/seismologie/aardbevingen&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jAEqN.png&quot; alt=&quot;&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;em&gt;map from KNMI, image links to live map&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;To take two examples from the above map, &lt;a href=&quot;https://knmi.nl/nederland-nu/seismologie/aardbevingen/detail_beving_2?eventid=knmi2020okqn&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weert&lt;/a&gt; and &lt;a href=&quot;https://knmi.nl/nederland-nu/seismologie/aardbevingen/detail_beving_14?eventid=knmi2020mdxc&quot; rel=&quot;nofollow noreferrer&quot;&gt;Farmsum&lt;/a&gt; I learn the hypocenter of one is tectonic and one is induced. Both have a precise location, different magnitudes (1.1 vs 0.2) and a depth (12 vs 3 km).&lt;/p&gt;&#xA;&lt;p&gt;What condition(s) need to be met to be able to determine the depth of a hypocenter of a microseism?&lt;/p&gt;&#xA;&lt;p&gt;I'm not an Earth scientist and although I'm not scared of scientific details I appreciate if an answer comes with subtitles in layman terms.&lt;/p&gt;&#xA;" OwnerUserId="125" LastEditorUserId="20867" LastEditDate="2020-08-21T06:28:19.557" LastActivityDate="2020-08-21T06:28:19.557" Title="What condition(s) need to be met to be able to determine the hypocenter of a microseism?" Tags="|seismology|microseism|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20056" PostTypeId="2" ParentId="20043" CreationDate="2020-08-11T20:28:38.213" Score="4" Body="&lt;p&gt;I will try to keep it a simple and short answer.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Is it possible to explain in simple terms what makes these waves happen?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The combination of solar activity (solar wind), Mars atmosphere and what is left of Mars magnetosphere.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;Is a similar or at least related phenomenon detectable in Earth's atmosphere?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Yes actually there is one called &lt;a href=&quot;https://en.wikipedia.org/wiki/Aurora&quot; rel=&quot;nofollow noreferrer&quot;&gt;Aurora Borealis&lt;/a&gt; or Northern lights.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In addition ask yourself another question since the Mars effect is in the UV zone thus above the visible (by humans) EM spectrum.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;How would Earth look like under the &lt;em&gt;&amp;quot;eyes&amp;quot;&lt;/em&gt; of an &lt;strong&gt;Ultraviolet Imaging&#xA;Spectrograph&lt;/strong&gt;?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I have not found any images related to that question, so i would say that i would expect to see something in the UV zone in Earth also.&lt;/p&gt;&#xA;&lt;p&gt;Furthermore i think you will find interesting that there is also a similar effect in Saturn. One of the many findings of &lt;a href=&quot;https://solarsystem.nasa.gov/missions/cassini/mission/spacecraft/cassini-orbiter/ultraviolet-imaging-spectrograph/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cassini's mission&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;EDIT&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Trying to answer the following question that became for me more clear after a relative comment.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;Why Mars has this behavior and is pulsing 3 exactly times per night?&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I have a theory for that phenomenon which i don't know if you will find it accepted as an answer. So here goes...&lt;/p&gt;&#xA;&lt;p&gt;I think the atmosphere in Mars acts like a giant capacitor that discharges at regular times at the UV spectrum area. How is this possible? Some facts to base the theory:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Mars atmosphere is thin.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The atmosphere of Mars is about 100 times thinner than Earth's (source: &lt;a href=&quot;https://www.space.com/16903-mars-atmosphere-climate-weather.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;space.co&lt;/a&gt;m), and it&#xA;is 95 percent carbon dioxide. Here's a breakdown of its composition,&#xA;according to a &lt;a href=&quot;https://nssdc.gsfc.nasa.gov/planetary/factsheet/marsfact.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA fact sheet&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Carbon dioxide: 95.32 percent&lt;/li&gt;&#xA;&lt;li&gt;Nitrogen: 2.7 percent&lt;/li&gt;&#xA;&lt;li&gt;Argon: 1.6 percent&lt;/li&gt;&#xA;&lt;li&gt;Oxygen: 0.13 percent&lt;/li&gt;&#xA;&lt;li&gt;Carbon monoxide: 0.08 percent&lt;/li&gt;&#xA;&lt;li&gt;Also, minor amounts  of: water, nitrogen oxide, neon, hydrogen-deuterium-oxygen, krypton and xenon&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;At this point we have to insert into our logic the term &lt;a href=&quot;https://en.wikipedia.org/wiki/Dynamic_equilibrium&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;code&gt;Dynamic Equilibrium&lt;/code&gt;&lt;/a&gt;. The most common example of a &lt;code&gt;Dynamic Equilibrium&lt;/code&gt; is something that happens in a closed can of soda. What is that? The balance between the following reactions per second:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;H&lt;sub&gt;2&lt;/sub&gt;CO&lt;sub&gt;3&lt;/sub&gt; → CO&lt;sub&gt;2&lt;/sub&gt; + H&lt;sub&gt;2&lt;/sub&gt;O&lt;/li&gt;&#xA;&lt;li&gt;CO&lt;sub&gt;2&lt;/sub&gt; + H&lt;sub&gt;2&lt;/sub&gt;O → H&lt;sub&gt;2&lt;/sub&gt;CO&lt;sub&gt;3&lt;/sub&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The above facts indicate that there is not much material to recycle in the chain presented in the image below:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oGe69.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oGe69.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;And in order to keep the &lt;code&gt;Dynamic Equilibrium&lt;/code&gt; between the gases in the Martian atmosphere there must be a reaction of NO becoming back to NO&lt;sub&gt;2&lt;/sub&gt;, that occurs at the same time in some other part of the planet,  such as this one:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;2 NO + O&lt;sub&gt;2&lt;/sub&gt; → 2 NO&lt;sub&gt;2&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;em&gt;(just remember 0.13% O&lt;sub&gt;2&lt;/sub&gt;, 2.7% N&lt;sub&gt;2&lt;/sub&gt; exist in Martian atmosphere, Oxygen found in Martian Fe&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt; AKA &lt;code&gt;rust&lt;/code&gt; is not counted - but it is a good clue that Mars had once Oxygen and Iron at surface levels)&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Last but not least Mars magnetosphere could be one of the reasons. Why? First of all a &lt;em&gt;Geographical map of the Martian crustal magnetic fields based on the spherical harmonics model by Morschhauser et al. [2014] at 200 km altitude, created from MGS MAG/ER data. The map is centered on the antimeridian with labels showing east longitude for a uniformly spaced 30 • grid. Contours show zero altitude relative the areoid&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.researchgate.net/figure/Geographical-map-of-the-Martian-crustal-magnetic-fields-based-on-the-spherical_fig12_322552368&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://www.researchgate.net/profile/Robin_Ramstad/publication/322552368/figure/fig12/AS:669384909549593@1536605207831/Geographical-map-of-the-Martian-crustal-magnetic-fields-based-on-the-spherical.jpg&quot; alt=&quot;9: Geographical map of the Martian crustal magnetic fields based on the spherical harmonics model by Morschhauser et al. [2014] at 200 km altitude, created from MGS MAG/ER data. The map is centered on the antimeridian with labels showing east longitude for a uniformly spaced 30 • grid. Contours show zero altitude relative the areoid.&quot;/&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Despite the fact that Mars no longer has an internal dynamo capable of&#xA;generating a large global magnetic field as on Earth, there is&#xA;evidence to suggest that Mars may once have had such a dynamo. This is&#xA;mainly supported by observations from the American satellite mission&#xA;MGS (Mars Global Surveyor), which from 1997 to 2006 measured the&#xA;magnetic field of Mars using a small magnetometer from an altitude of&#xA;100-400 km above the planet’s surface. These measurements showed the&#xA;existence of powerful magnetic crustal fields on the planet’s surface,&#xA;far more powerful than those found on Earth.&lt;/p&gt;&#xA;&lt;p&gt;The presence of these crustal fields gives rise to local&#xA;mini-magnetospheres, i.e. small areas where the lines of the magnetic&#xA;field locally protect the planet surface from electrically charged&#xA;particles. Mini-magnetospheres occur when a magnetic field line is&#xA;connected to two different points on the Martian surface, thus&#xA;creating a kind of bubble. Between these ‘bubbles’, one end of the&#xA;magnetic field lines can be connected to the planet and the other to&#xA;the interplanetary magnetic field (IMF). (source: &lt;a href=&quot;https://www.space.dtu.dk/english/Research/Universe_and_Solar_System/magnetic_field&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mars’ magnetic field&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;If all off the above are correct (i hope i did not forget to mention anything more) then this phenomenon could occur periodically (3 times per night) and at certain geographical regions, simply because it is following a cycle of events&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user19169" LastEditorDisplayName="user19169" LastEditDate="2020-08-15T10:10:32.923" LastActivityDate="2020-08-15T10:10:32.923" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="20057" PostTypeId="2" ParentId="2760" CreationDate="2020-08-12T05:04:33.970" Score="2" Body="&lt;p&gt;Another good historical perspective from this blog:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://lablemminglounge.blogspot.com/2006/09/iridium-anomaly-as-historical-artifact.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://lablemminglounge.blogspot.com/2006/09/iridium-anomaly-as-historical-artifact.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;h3&gt;Iridium anomaly as historical artifact&lt;/h3&gt;&#xA;&lt;p&gt;Everybody knows that way back in 1980, Alvarez et al. showed that&#xA;Italian sediments deposited on the Cretaceous / Tertiary boundary (and&#xA;NOT the Cretaceous / Paleogene boundary, I might add) are enriched in&#xA;the element iridium. The term “Iridium anomaly” was thus coined as a&#xA;quick and dirty way to identify extra-terrestrial impactors.&lt;/p&gt;&#xA;&lt;p&gt;The idea is simple: when the Earth differentiated into core and&#xA;mantle, the PGE elements (Ru, Rh, Pd, Os, Ir, and Pt) partitioned into&#xA;the core, since they are soluble in metallic iron, but excluded from&#xA;silicates. Thus, undifferentiated material has a much higher PGE&#xA;content than the silicate Earth, allowing anomalously high&#xA;concentrations of these elements to be used as an indicator of&#xA;undifferentiated material.&lt;/p&gt;&#xA;&lt;p&gt;What this idea does not explain, though, is the following:&lt;/p&gt;&#xA;&lt;p&gt;Why Iridium? Why don’t we all learn about a platinum anomaly or a&#xA;ruthenium anomaly in first-year geology?&lt;/p&gt;&#xA;&lt;p&gt;The answer to that question is actually quite simple, but it involves&#xA;nuclear physics, not geology. Iridium was the PGE detected by the&#xA;Alvarez study because it is the only PGE that can be identified in&#xA;sub-ppb concentrations using neutron activation. Prior to the&#xA;refinement of ICP mass spectrometry in the 90’s, neutron activation&#xA;analysis was the most sensitive analytical technique available to&#xA;geologists. But because it is a nuclear, and not a chemical or ionic&#xA;technique, its applicability depends on whether or not any isotopes of&#xA;a given element happen to have high cross-sections that capture&#xA;neutrons to form unstable, gamma-emitting products.&lt;/p&gt;&#xA;&lt;p&gt;It just so happens that the two naturally occurring iridium isotopes&#xA;have relatively large cross sections, and form short-lived,&#xA;gamma-emitting products. The other PGE’s do not. So the iridium&#xA;anomaly was detected simply because it was the most detectable, using&#xA;the technology available at the time.&lt;/p&gt;&#xA;&lt;p&gt;Here in the 21st century, it is generally cheaper, easier, and safer&#xA;to dissolve a sample and run solution ICPMS to get all six PGE’s.&#xA;Unless, of course, you give yourself osmium poisoning from mishandling&#xA;your spike.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-08-12T05:04:33.970" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20058" PostTypeId="1" CreationDate="2020-08-12T09:08:28.207" Score="1" ViewCount="84" Body="&lt;p&gt;This site&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://grillo.io/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://grillo.io/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;and here&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://github.com/openeew/openeew/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://github.com/openeew/openeew/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;advertises such a system. But from the make-up of the site and no geo-science related work that they link to (at least what I could find) I assume it is just an advertisement for the internet of things (IoT) and economic interests outweigh a scientific usefulness.&lt;/p&gt;&#xA;&lt;p&gt;But opinion aside, does a denser (home made) sensor network than the status quo of earthquake watchers in the hot spots and ODAS buoys really shorten warning times? Hasn't this been worked on in the wake of the 2004 Indian Ocean tsunami?&lt;/p&gt;&#xA;&lt;p&gt;It would be interesting to know if home made sensors and IoT really could contribute to shorten warning times from official sensor networks.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-08-24T12:28:14.763" LastActivityDate="2020-08-24T12:28:14.763" Title="OpenEEW - earthquake early warning by everyone?" Tags="|earthquakes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20059" PostTypeId="1" CreationDate="2020-08-12T11:25:39.753" Score="1" ViewCount="45" Body="&lt;p&gt;I want to use the spei() function in the SPEI package on a waterbalance dataset from 2015-2020 of 99 locations. The waterbalance is calculated out of MODIS PET values (8-day summed to monthly) and CHIRPS precipitation values (daily summed to monthly). MODIS PET returns NA's for several weeks in the year, and because the water balance is cumulative I return every month containing NA's as NA.&#xA;The input data thus is formatted as follows: &lt;a href=&quot;https://drive.google.com/file/d/1oDoY9JzuAy4EefKre22FUMzbTo_zehq-/view?usp=sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://drive.google.com/file/d/1oDoY9JzuAy4EefKre22FUMzbTo_zehq-/view?usp=sharing&lt;/a&gt;&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt; head(data)&#xA;  year month_num      AN01      AN02      AN03     AN04     AN05     AN06      AN07      AN08      AN09     AN10     AN11     AN12     AN13     AN14     AN15&#xA;1 2015         1        NA        NA        NA 140.6656 140.6656 140.6656 140.22344 140.22344 140.22344 140.6656 140.6656 140.6656 139.7125 139.7125 139.7125&#xA;2 2015         2 119.66563 119.66563 119.66563 121.3547 121.3547 121.3547 119.82969 119.82969 119.82969 121.3547 121.3547 121.3547 118.0609 118.0609 118.0609&#xA;3 2015         3        NA        NA        NA       NA       NA       NA        NA        NA        NA       NA       NA       NA       NA       NA       NA&#xA;4 2015         4        NA        NA        NA       NA       NA       NA        NA        NA        NA       NA       NA       NA       NA       NA       NA&#xA;5 2015         5 153.68281 153.68281 153.68281 153.4719 153.4719 153.4719        NA        NA        NA 153.4719 153.4719 153.4719 153.8500 153.8500 153.8500&#xA;6 2015         6  18.00313  18.00313  18.00313       NA       NA       NA  17.79688  17.79688  17.79688       NA       NA       NA  18.2000  18.2000  18.2000&#xA;       CA01      CA02      CA03      CA04      CA05      CA06      CA07      CA08      CA09      CA10      CA11      CA12      CA13      CA14      CA15&#xA;1        NA        NA        NA        NA        NA        NA        NA        NA        NA 122.91406 122.91406 122.91406        NA        NA        NA&#xA;2        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA&#xA;3        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA  81.07344  81.07344  81.07344&#xA;4        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA&#xA;5 110.16875 110.05156 110.05156 104.26406 104.26406 104.26406 110.14531 110.19219 110.19219 117.41250 117.41250 117.41250 117.30469 117.30469 117.30469&#xA;6  14.29219  14.18594  14.18594  13.42969  13.42969  13.42969  14.40312  14.42188  14.42188  19.60312  19.60312  19.60312  19.40469  19.40469  19.40469&#xA;       CA16      CA17      CA18      CA19      CA20      CA21      CA22      CA23      CA24      CA25      CA26      CA27      CA28     CA29     CA30      NU01&#xA;1 121.86875 121.86875 121.86875        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA       NA       NA        NA&#xA;2        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA       NA       NA        NA&#xA;3        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA  96.53281  96.53281        NA       NA       NA  92.86562&#xA;4        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA       NA       NA        NA&#xA;5 117.31562 117.31562 117.31562 110.19375 110.19375 110.19375 110.10781 110.10781 110.10781 110.15625 110.20469 110.20469 117.14687 117.1125 117.1125 150.16406&#xA;6  19.52656  19.52656  19.52656  14.30937  14.30937  14.30937  14.29531  14.29531  14.29531  14.35469  14.36875  14.36875  19.27656  19.3000  19.3000  19.27656&#xA;       NU02      NU03      NU04      NU05      NU06      NU10      NU11      NU12      NU13      NU14      NU15      NU16      NU17      NU18      NU19&#xA;1        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA 121.43906 121.43906 121.43906        NA&#xA;2        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA 103.69688&#xA;3  92.86562  92.86562  91.94844  91.94844  91.94844        NA        NA        NA  92.86562  92.86562  92.86562        NA        NA        NA  92.45312&#xA;4        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA&#xA;5 150.16406 150.16406 150.05781 150.05781 150.05781 150.18750 150.18750 150.18750 150.16406 150.16406 150.16406 150.50156 150.50156 150.50156 150.14062&#xA;6  19.27656  19.27656  19.24687  19.24687  19.24687  19.40781  19.40781  19.40781  19.27656  19.27656  19.27656  19.67813  19.67813  19.67813  19.34219&#xA;       NU20      NU21      NU22      NU23      NU24      NU25      NU26      NU27      PU01      PU02      PU03      PU04      PU05      PU06      PU07&#xA;1        NA        NA        NA        NA        NA 121.50938 121.50938 121.50938        NA        NA        NA        NA        NA        NA 133.13594&#xA;2 103.69688 103.69688 101.83594 101.83594 101.83594 101.92656 101.92656 101.92656        NA        NA        NA        NA        NA        NA 111.66719&#xA;3  92.45312  92.45312  92.87812  92.87812  92.87812  92.93281  92.93281  92.93281        NA  87.29688  87.29688        NA        NA        NA        NA&#xA;4        NA        NA        NA        NA        NA 148.44375 148.44375 148.44375        NA        NA        NA        NA        NA        NA 150.31250&#xA;5 150.14062 150.14062 150.27656 150.27656 150.27656 150.16563 150.16563 150.16563 113.30312 113.21875 113.21875 155.24844 155.24844 155.24844        NA&#xA;6  19.34219  19.34219  19.43750  19.43750  19.43750  19.40156  19.40156  19.40156  12.38281  12.37187  12.37187  24.44531  24.44531  24.44531  24.56719&#xA;       PU08      PU09     PU10     PU11     PU12      PU13      PU14      PU15      PU16      PU17      PU18      PU19      PU20      PU21      PU22      PU23&#xA;1 133.13594 133.13594       NA       NA       NA        NA        NA        NA        NA        NA        NA 109.91250        NA 110.00781 132.42812 132.42812&#xA;2 111.66719 111.66719       NA       NA       NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA&#xA;3        NA        NA       NA       NA       NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA&#xA;4 150.31250 150.31250       NA       NA       NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA        NA&#xA;5        NA        NA 113.1641 113.1641 113.1641 113.08125 113.08125 113.08125 106.19062 155.17656 106.19062 106.11875 106.16875 106.10625        NA        NA&#xA;6  24.56719  24.56719  12.4000  12.4000  12.4000  12.30625  12.30625  12.30625  10.29688  24.40938  10.29688  10.27656  10.31719  10.31406  24.49531  24.49531&#xA;       PU24      PU25     PU26     PU27      PU28      PU29      PU30&#xA;1 132.42812        NA       NA       NA        NA        NA        NA&#xA;2        NA        NA       NA       NA        NA        NA        NA&#xA;3        NA        NA       NA       NA        NA        NA        NA&#xA;4        NA        NA       NA       NA        NA        NA        NA&#xA;5        NA 113.07812       NA       NA 113.00625 113.00625 113.00625&#xA;6  24.49531  12.39844 12.35938 12.35938  12.39531  12.39531  12.39531&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Now I want to calculate the SPEI for different timeframes (1,3,6,12), so I apply the SPEI function on my dataset, but when I for instance apply SPEI-1, I get:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;&amp;gt; spei1all &amp;lt;- spei(data, 1, na.rm = TRUE)&#xA;&amp;gt; head(spei1all$fitted)&#xA;     year month_num        AN01        AN02        AN03 AN04 AN05 AN06 AN07 AN08 AN09 AN10 AN11 AN12        AN13        AN14        AN15       CA01       CA02&#xA;[1,]   NA        NA          NA          NA          NA   NA   NA   NA   NA   NA   NA   NA   NA   NA          NA          NA          NA         NA         NA&#xA;[2,]   NA        NA          NA          NA          NA   NA   NA   NA   NA   NA   NA   NA   NA   NA          NA          NA          NA         NA         NA&#xA;[3,]   NA        NA          NA          NA          NA   NA   NA   NA   NA   NA   NA   NA   NA   NA          NA          NA          NA         NA         NA&#xA;[4,]   NA        NA          NA          NA          NA   NA   NA   NA   NA   NA   NA   NA   NA   NA          NA          NA          NA         NA         NA&#xA;[5,]   NA        NA -0.04473888 -0.04473888 -0.04473888   NA   NA   NA   NA   NA   NA   NA   NA   NA -0.04556608 -0.04556608 -0.04556608 -0.1440235 -0.1437865&#xA;[6,]   NA        NA          NA          NA          NA   NA   NA   NA   NA   NA   NA   NA   NA   NA          NA          NA          NA  0.1270792  0.1252743&#xA;           CA03       CA04       CA05       CA06       CA07       CA08       CA09        CA10        CA11        CA12        CA13        CA14        CA15&#xA;[1,]         NA         NA         NA         NA         NA         NA         NA          NA          NA          NA          NA          NA          NA&#xA;[2,]         NA         NA         NA         NA         NA         NA         NA          NA          NA          NA          NA          NA          NA&#xA;[3,]         NA         NA         NA         NA         NA         NA         NA          NA          NA          NA          NA          NA          NA&#xA;[4,]         NA         NA         NA         NA         NA         NA         NA          NA          NA          NA          NA          NA          NA&#xA;[5,] -0.1437865 -0.2131104 -0.2131104 -0.2131104 -0.1439872 -0.1443327 -0.1443327 -0.09725626 -0.09725626 -0.09725626 -0.09712531 -0.09712531 -0.09712531&#xA;[6,]  0.1252743  0.1821326  0.1821326  0.1821326  0.1347416  0.1379326  0.1379326  0.12373387  0.12373387  0.12373387  0.12174635  0.12174635  0.12174635&#xA;          CA16      CA17      CA18       CA19       CA20       CA21       CA22       CA23       CA24       CA25       CA26       CA27        CA28       CA29&#xA;[1,]        NA        NA        NA         NA         NA         NA         NA         NA         NA         NA         NA         NA          NA         NA&#xA;[2,]        NA        NA        NA         NA         NA         NA         NA         NA         NA         NA         NA         NA          NA         NA&#xA;[3,]        NA        NA        NA         NA         NA         NA         NA         NA         NA         NA         NA         NA          NA         NA&#xA;[4,]        NA        NA        NA         NA         NA         NA         NA         NA         NA         NA         NA         NA          NA         NA&#xA;[5,]        NA        NA        NA -0.1435276 -0.1435276 -0.1435276 -0.1433653 -0.1433653 -0.1433653 -0.1435422 -0.1427202 -0.1427202 -0.09792318 -0.0985231&#xA;[6,] 0.1241692 0.1241692 0.1241692  0.1258252  0.1258252  0.1258252  0.1325940  0.1325940  0.1325940  0.1315080  0.1344834  0.1344834  0.12496444  0.1167191&#xA;           CA30 NU01 NU02 NU03        NU04        NU05        NU06        NU10        NU11        NU12 NU13 NU14 NU15      NU16      NU17      NU18        NU19&#xA;[1,]         NA   NA   NA   NA          NA          NA          NA          NA          NA          NA   NA   NA   NA        NA        NA        NA          NA&#xA;[2,]         NA   NA   NA   NA          NA          NA          NA          NA          NA          NA   NA   NA   NA        NA        NA        NA          NA&#xA;[3,]         NA   NA   NA   NA          NA          NA          NA          NA          NA          NA   NA   NA   NA        NA        NA        NA          NA&#xA;[4,]         NA   NA   NA   NA          NA          NA          NA          NA          NA          NA   NA   NA   NA        NA        NA        NA          NA&#xA;[5,] -0.0985231   NA   NA   NA -0.02117332 -0.02117332 -0.02117332 -0.02190537 -0.02190537 -0.02190537   NA   NA   NA        NA        NA        NA -0.02135286&#xA;[6,]  0.1167191   NA   NA   NA  0.61505613  0.61505613  0.61505613  0.61339831  0.61339831  0.61339831   NA   NA   NA 0.6261692 0.6261692 0.6261692          NA&#xA;            NU20        NU21      NU22      NU23      NU24     NU25     NU26     NU27         PU01      PU02      PU03      PU04      PU05      PU06      PU07&#xA;[1,]          NA          NA        NA        NA        NA       NA       NA       NA           NA        NA        NA        NA        NA        NA        NA&#xA;[2,]          NA          NA        NA        NA        NA       NA       NA       NA           NA        NA        NA        NA        NA        NA        NA&#xA;[3,]          NA          NA        NA        NA        NA       NA       NA       NA           NA        NA        NA        NA        NA        NA        NA&#xA;[4,]          NA          NA        NA        NA        NA 1.111417 1.111417 1.111417           NA        NA        NA        NA        NA        NA        NA&#xA;[5,] -0.02135286 -0.02135286        NA        NA        NA       NA       NA       NA -0.004715343        NA        NA 0.1010535 0.1010535 0.1010535        NA&#xA;[6,]          NA          NA 0.6152473 0.6152473 0.6152473       NA       NA       NA  0.701645612 0.7026218 0.7026218        NA        NA        NA 0.7763708&#xA;          PU08      PU09         PU10         PU11         PU12         PU13         PU14         PU15      PU16      PU17      PU18       PU19       PU20&#xA;[1,]        NA        NA           NA           NA           NA           NA           NA           NA        NA        NA        NA         NA         NA&#xA;[2,]        NA        NA           NA           NA           NA           NA           NA           NA        NA        NA        NA         NA         NA&#xA;[3,]        NA        NA           NA           NA           NA           NA           NA           NA        NA        NA        NA         NA         NA&#xA;[4,]        NA        NA           NA           NA           NA           NA           NA           NA        NA        NA        NA         NA         NA&#xA;[5,]        NA        NA -0.005900812 -0.005900812 -0.005900812 -0.005597071 -0.005597071 -0.005597071        NA 0.1011388        NA -0.1207526 -0.1210379&#xA;[6,] 0.7763708 0.7763708  0.702357629  0.702357629  0.702357629  0.700751150  0.700751150  0.700751150 0.3631265 0.7692896 0.3631265  0.3722869         NA&#xA;           PU21 PU22 PU23 PU24         PU25      PU26      PU27         PU28         PU29         PU30&#xA;[1,]         NA   NA   NA   NA           NA        NA        NA           NA           NA           NA&#xA;[2,]         NA   NA   NA   NA           NA        NA        NA           NA           NA           NA&#xA;[3,]         NA   NA   NA   NA           NA        NA        NA           NA           NA           NA&#xA;[4,]         NA   NA   NA   NA           NA        NA        NA           NA           NA           NA&#xA;[5,] -0.1216638   NA   NA   NA -0.004863862        NA        NA -0.007700107 -0.007700107 -0.007700107&#xA;[6,]  0.3728449   NA   NA   NA           NA 0.6935715 0.6935715  0.699429193  0.699429193  0.699429193&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Even though I apply &lt;code&gt;na.rm = TRUE&lt;/code&gt; the SPEI returns NA's or values at unexpected places. It seems like there is something wrong with how I format my dataframe?&lt;/p&gt;&#xA;" OwnerUserId="20889" LastEditorUserId="20889" LastEditDate="2020-10-03T17:54:05.080" LastActivityDate="2020-10-03T17:54:05.080" Title="R SPEI package on waterbalance timeseries for multiple locations with NA's: unexpected data output distribution" Tags="|climate|precipitation|statistics|drought|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20060" PostTypeId="1" AcceptedAnswerId="20061" CreationDate="2020-08-12T12:26:05.500" Score="3" ViewCount="174" Body="&lt;p&gt;New data about Ceres has just been released. &lt;a href=&quot;https://doi.org/10.1038/s41550-020-1168-2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Raymond et al. (2020)&lt;/a&gt; show the existence of gravity anomalies interpreted as low density pockets of brine under the crust. They show how impacts can trigger eruption of this brine onto the surface.&lt;/p&gt;&#xA;&lt;p&gt;I understand how a low density layer can &lt;em&gt;remain trapped&lt;/em&gt; under a higher density layer by lack of pores and/or fractures to rise through by buoyancy. However, I cannot figure how it &lt;em&gt;got trapped&lt;/em&gt; there in the first place? For subsurface oceans under an icy crust (like Europa), I can imagine a simple freezing mechanism, but Ceres has a &lt;em&gt;rocky&lt;/em&gt; crust.&lt;/p&gt;&#xA;&lt;p&gt;Wikipedia's &lt;a href=&quot;https://en.wikipedia.org/wiki/Ocean_world#Formation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ocean World - Formation&lt;/a&gt; goes:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Since water is highly soluble in magma, a large fraction of the&#xA;planet's water content will initially be trapped in the mantle. As the&#xA;planet cools and the mantle begins to solidify from the bottom up,&#xA;large amounts of water (between 60% and 99% of the total amount in the&#xA;mantle) are exsolved to form a steam atmosphere, which may eventually&#xA;condense to form an ocean.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;But it doesn't really help as it applies to surface oceans only. Neither does &lt;a href=&quot;https://en.wikipedia.org/wiki/Ocean#Extraterrestrial_oceans&quot; rel=&quot;nofollow noreferrer&quot;&gt;Extraterrestrial oceans&lt;/a&gt; on that particular matter.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;How do subsurface oceans form under a rocky crust?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-12-04T17:41:07.157" Title="How do subsurface oceans form under a rocky crust?" Tags="|planetary-science|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20061" PostTypeId="2" ParentId="20060" CreationDate="2020-08-13T13:02:27.397" Score="3" Body="&lt;p&gt;As Jean-Marie Prival comments, Ceres doesn't have a rocky crust.  It has an icy crust in which rocky matter is embedded from asteroid impacts.  I'd rather see this comment turned into an answer than reinvent the wheel on that dwarf planet.  In case they &amp;quot;die&amp;quot;, the relevant comments are quoted below the main body of the answer..&lt;/p&gt;&#xA;&lt;p&gt;Instead, here I consider a celestial body closer at hand.  Earth does not have a subterranean ocean but it can produce water deep in the mantle, extracted from rock.  As described in &lt;a href=&quot;https://space.stackexchange.com/a/33570/28871&quot;&gt;this answer&lt;/a&gt; from Space Exploration Stack Exchange, a high-pressure solid phase of water, Ice VII, has been identified as inclusions in diamonds; the presence of these inclusions implies that water exists in the molecular state (&lt;span class=&quot;math-container&quot;&gt;$\text{H}_2\text{O}$&lt;/span&gt;) as distinct from hydroxyl groups in minerals.  The water is first trapped as a supercritical fluid as the diamonds form deep in the mantle, then condenses to Ice VII as the diamonds cool at the surface but retain mantle-level pressures internally.&lt;/p&gt;&#xA;&lt;p&gt;Water in Earth's mantle likely does not come directly from surface oceans, but from hydroxide-bearing minerals in the rock.  When the rock is cycled downwards by plate tectonics, it becomes hot enough to decompose the hydroxides (hydroxides of silicon, aluminum, iron, calcium, and magnesium, the elements to which hydroxyl groups are most likely to be bound in crustal rocks, all decompose well below 1000°C), thus generating the subterranean water.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;Previous comments&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;There seems to be a whole bunch of publications on the matter: nature.com/articles/s41550-020-1146-8, nature.com/articles/s41550-020-1019-1, nature.com/articles/s41561-020-0581-6. I don't have access to all of them (too expensive ...). Maybe there's some useful information on the matter. – user20217 Aug 12 at 12:59&lt;/p&gt;&#xA;&lt;p&gt;Interesting! The first one states that &amp;quot;the interior of Ceres consists of (1) a thin lag deposit (regolith) layer, (2) an icy crust that contains the bulk of an origin ocean [...]&amp;quot;. That would explain a lot, the rocky layer being created on top of the icy surface by impacts. What got me was this passage in doi.org/10.1038/s41467-020-15973-8 : &amp;quot;Ceres [...] is partially differentiated into a rocky interior and a comparatively more volatile-rich crust, which is composed of rock, salts, clathrates, and ≤ 40% water ice.&amp;quot; Looks like the crust might not be so &amp;quot;rocky&amp;quot; after all... – Jean-Marie Prival Aug 12 at 14:10&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2020-12-04T17:41:07.157" LastActivityDate="2020-12-04T17:41:07.157" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="20062" PostTypeId="1" CreationDate="2020-08-14T04:36:54.513" Score="1" ViewCount="365" Body="&lt;p&gt;Every ten minutes, I make an API call to the SMHI's API with the GPS coordinates less than 1 km from here (which cannot possibly matter for accuracy, but does for privacy). SMHI is the Swedish weather forecast &amp;quot;ministry&amp;quot; or however one would translate it. They've been collecting weather stats since the mid-1700s, so you'd think they would be pretty skilled by now. I think they have some of the oldest weather data in the world, but don't quote me on that.&lt;/p&gt;&#xA;&lt;p&gt;I don't really care about the temperatures, but I do look out for rain. In fact, I automatically clear and update my little &amp;quot;calendar&amp;quot; in my &amp;quot;control panel&amp;quot; with little icons for when this API claims that it will rain in the next 7 days, so that I constantly know how long it's left until the next time it rains. In theory.&lt;/p&gt;&#xA;&lt;p&gt;I love rain.&lt;/p&gt;&#xA;&lt;p&gt;Well, yesterday, my calendar was full of those sweet rain icons. I rubbed my hands and started looking forward to a nice week full of wonderful rain, yet now when I wake up, it has updated to be six full days left until the next time it rains again. And this is far from the first time. In fact, it happens all the time. They basically seem to have no idea whatsoever when it's going to rain, until just before it starts.&lt;/p&gt;&#xA;&lt;p&gt;Are modern weather forecasts this inaccurate? Are they just particularly incompetent over at SMHI? I did integrate another, international API. I guess I should write some mechanism to compare their data with SMHI's. However, I suspect that the international API might well just use SMHI's data for coordinates within Sweden, and I'm not exactly eager to figure out how to make such a comparison.&lt;/p&gt;&#xA;&lt;p&gt;Is rain forecasting really this inaccurate still? Isn't one week a pretty reasonable window to expect accurate weather data?&lt;/p&gt;&#xA;&lt;p&gt;This makes me really wonder how accurate those &amp;quot;farmer's calendar&amp;quot; predictions were. It would interest me to see how right they have been compared to modern &amp;quot;scientific&amp;quot; weather forecasting.&lt;/p&gt;&#xA;" OwnerUserId="20897" LastActivityDate="2020-08-14T15:22:24.447" Title="Can they still not predict rain even one week in advance?" Tags="|meteorology|weather-forecasting|rainfall|rain|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20063" PostTypeId="1" CreationDate="2020-08-14T07:11:26.523" Score="3" ViewCount="6227" Body="&lt;p&gt;According to the &lt;a href=&quot;https://www.grc.nasa.gov/www/k-12/VirtualAero/BottleRocket/airplane/atmos.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;GRC NASA website&lt;/a&gt;, Earth's atmosphere is a thin sheet of air extending from the surface of the Earth to the edge of space. Some videos on youtube also point out that if the Earth is the size of an apple, its atmosphere is just as thick as the apple's skin. But when we look at some diagrams, Earth's atmosphere is thick. For instance, when someone says that the atmosphere is a thin sheet of air, does he/she take in to account the thick layer thermosphere or exosphere? Or is it just that the diagrams we commonly see have inaccurate visual representation?&lt;/p&gt;&#xA;" OwnerUserId="20898" LastEditorUserId="-1" LastEditDate="2020-08-15T21:14:28.533" LastActivityDate="2023-08-25T05:46:26.967" Title="How thin is our atmosphere relative to the size of Earth?" Tags="|meteorology|atmosphere|atmosphere-modelling|" AnswerCount="4" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20064" PostTypeId="2" ParentId="20063" CreationDate="2020-08-14T10:10:06.947" Score="7" Body="&lt;p&gt;The answer to your question depends on where one defines the edge of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Earth&quot; rel=&quot;noreferrer&quot;&gt;atmosphere&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The Earth's atmosphere is layered. The thickness, density of composition of each layer varies. The five layers are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Exosphere: 700 to 10,000 km (440 to 6,200 miles)&lt;/li&gt;&#xA;&lt;li&gt;Thermosphere: 80 to 700 km (50 to 440 miles)&lt;/li&gt;&#xA;&lt;li&gt;Mesosphere: 50 to 80 km (31 to 50 miles)&lt;/li&gt;&#xA;&lt;li&gt;Stratosphere: 12 to 50 km (7 to 31 miles)&lt;/li&gt;&#xA;&lt;li&gt;Troposphere: 0 to 12 km (0 to 7 miles)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Being the outermost layer, the exosphere is the layer with the most nebulous upper boundary. It is also the layer with the lowest density and it is primarily composed of very low density hydrogen and helium, particularly in the outer/upper reaches.&lt;/p&gt;&#xA;&lt;p&gt;Because of the low density of the exosphere and also because the &lt;a href=&quot;https://en.wikipedia.org/wiki/K%C3%A1rm%C3%A1n_line&quot; rel=&quot;noreferrer&quot;&gt;Karman Line&lt;/a&gt;, which is 100 km above the Earth, which the line designated where Earth ends and outer space begins, the exosphere is sometimes ignored.&lt;/p&gt;&#xA;&lt;p&gt;So if one accepts the top of the Thermosphere as being the &lt;strong&gt;effective&lt;/strong&gt; upper boundary of the atmosphere the effective thickness of the atmosphere is only 700 km compared the &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth_radius&quot; rel=&quot;noreferrer&quot;&gt;radius of the Earth&lt;/a&gt;, which is 6370 km.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2020-08-21T21:37:45.343" LastActivityDate="2020-08-21T21:37:45.343" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20067" PostTypeId="2" ParentId="20062" CreationDate="2020-08-14T15:22:24.447" Score="2" Body="&lt;p&gt;I am going to pause and say I don't know anything about SMHI. Therefore I can't comment on their competency. But I am sure they don't appreciate being called incompetent. If you are so passionate about rain, have you considered looking at weather prediction, and trying to beat them?&lt;/p&gt;&#xA;&lt;p&gt;It is well known that &lt;a href=&quot;https://www.sciencedaily.com/releases/2019/04/190415154722.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;the limit for predictability of weather is 2 weeks&lt;/a&gt;. Past that, climatology is just as accurate as modern forecasts in the grand scheme of things. Individual events may have more or less predictability. Precipitation is very hard to forecast, for various reasons including the lack of quality water vapor observations, the complexity of microphysics, and the interaction with other atmospheric physics.&lt;/p&gt;&#xA;&lt;p&gt;It really depends on the mechanism for rainfall. Different mechanisms have different amounts of predictability. For example, &lt;a href=&quot;https://www.nhc.noaa.gov/verification/verify5.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;a 5-day forecast of a hurricane is off by an average of 200 miles (321 km)&lt;/a&gt;. Thunderstorms, especially individual cells, are hard to predict without probability. Extratropical cyclones are a bit easier predicted.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.cnn.com/2016/08/15/health/old-farmers-almanac-weather-prediction-accuracy/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Farmers almanacs are notoriously inaccurate&lt;/a&gt;. Moreover, their &amp;quot;predictions&amp;quot; are fuzzy. You'll find better accuracy with actual forecasts.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-08-14T15:22:24.447" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20068" PostTypeId="1" CreationDate="2020-08-14T17:41:56.600" Score="2" ViewCount="152" Body="&lt;p&gt;I've been writing a 2D interpolation scheme for use on the globe which utilizes lat/lon values.  Once I try to use values closer to the poles, latitude distortion becomes an issue.  For example:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;270,-86 ---------- 0, -90          This looks like an ordinary square on the globe&#xA;        |        |                  but when these values are projected to a plane,&#xA;        |        |                  they create a shape that's unworkable.&#xA;        |        |                  Note that opposite corners have the same latitude.&#xA;225,-84 ---------- 180,-86 &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;I've been converting from spherical to cartesian coordinates in an attempt to create a 2D plane but there's still the issue of these planes existing in three dimensions and I've had difficulty &amp;quot;flattening&amp;quot; them.  Surely there must be a common method for dealing with the latitude distortion near the poles but I don't know what it is.  Any help would be much appreciated.&lt;/p&gt;&#xA;&lt;p&gt;Thanks.&lt;/p&gt;&#xA;" OwnerUserId="20900" LastActivityDate="2020-08-19T18:03:17.390" Title="Difficulty interpolating near poles using lat/lons" Tags="|coordinate-system|interpolation|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20072" PostTypeId="2" ParentId="20063" CreationDate="2020-08-15T15:22:15.763" Score="3" Body="&lt;p&gt;The referenced website claims that &amp;quot;The Earth's atmosphere is an extremely thin sheet of air extending from the surface of the Earth to the edge of space. If the Earth were the size of a basketball, a tightly held pillowcase would represent the thickness of the atmosphere.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;The website apparently is using the altitude at which the US awards someone Astronaut Wings as &amp;quot;the edge of space&amp;quot; -- 50 miles, or about 80 kilometers. Shrinking the Earth to the size of a basketball would shrink 80 kilometers to 1.5 millimeters, which is about the thickness of a pillowcase. Things can orbit the Earth and have orbited the Earth at 85 kilometers altitude (for a few orbits). Since about 99.998% of the mass of the atmosphere is at an altitude of 85 kilometers or less, that usage is not unreasonable.&lt;/p&gt;&#xA;&lt;p&gt;The remaining 0.002% of the atmosphere's mass gets thinner and thinner with increasing altitude, but the atmosphere arguably continues to at least half of the way to the Moon. In that sense, claiming that the Earth has a thin atmosphere is incorrect. But that is a thin claim (pun intended).&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-08-15T15:22:15.763" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20073" PostTypeId="1" CreationDate="2020-08-16T00:12:37.713" Score="1" ViewCount="52" Body="&lt;p&gt;According to many articles around the web as well as the SpaceX official website (&lt;a href=&quot;https://www.spacex.com/human-spaceflight/earth/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.spacex.com/human-spaceflight/earth/index.html&lt;/a&gt;), Elon Musk plans to replace intercontinental flights with rockets traveling in a low Earth trajectory to send people to anywhere in the world in 30 minutes or less.  What I want to know is: Would sending people between continents on rockets produce more, the same, or less carbon emissions per person than intercontinental flights, assuming as little fuel as possible per person is burned when sending&#xA;the people into their low Earth trajectory?&lt;/p&gt;&#xA;" OwnerUserId="20911" LastActivityDate="2020-08-16T00:12:37.713" Title="What is the carbon footprint of Spacex's plan for earth-to-earth transport plan compared to commercial aviation?" Tags="|co2|environmental-protection|transportation|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20074" PostTypeId="2" ParentId="20068" CreationDate="2020-08-16T13:43:18.183" Score="1" Body="&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\color{blue}{\text{The answer here presumes that Earth is a sphere.}}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\color{blue}{\text{This is not fully true, but the question seems to build in that assumption.}}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\color{blue}{\text{That should be clarified to determine if this answer is relevant.}}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Do not use a 2D-plane which does not generally exist for four points.  Use a tetrahedron.  You can interpolate inside the tetrahedron and then project the interpolated point (which will be inside the globe) radially onto the globe's surface.&lt;/p&gt;&#xA;&lt;p&gt;Say you pick the South Pole, S, and three points A, B, C at 60° south latitude and longitude 0°, 90° east, 90° west.  Converting these coordinates to Cartesian form with the South Pole at &lt;span class=&quot;math-container&quot;&gt;$(0,0,-1)$&lt;/span&gt; prime meridian passing through &lt;span class=&quot;math-container&quot;&gt;$(1,0,0)$&lt;/span&gt;, we get the coordinates&lt;/p&gt;&#xA;&lt;p&gt;South Pole = &lt;span class=&quot;math-container&quot;&gt;$(0,0,-1)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;A = &lt;span class=&quot;math-container&quot;&gt;$(1/2,0,-\sqrt3/2)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;B = &lt;span class=&quot;math-container&quot;&gt;$(0,1/2,-\sqrt3/2)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;C = &lt;span class=&quot;math-container&quot;&gt;$(0,-1/2,-\sqrt3/2)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now suppose you want to interpolate with a weight of 1/2 for S and 1/6 for each of the other three points.  Take the linear combinations of the above coordinates with those coefficients to get a point P inside the tetrahedron:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$P=(1/2)(0,0,-1)+(1/6)(1/2,0,-\sqrt3/2)+(1/6)(0,1/2,-\sqrt3/2)+(1/6)(0,-1/2,-\sqrt3/2)=(1/12,0,-(2+\sqrt3)/4)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Point P has the following physical significance:  if you draw the smaller tetrahedron PABC, opposite S, then this tetrahedron has 1/2 the volume of the big tetrahedron ABCS, where 1/2 is the coefficient you put in for S.  For this choice of P the corresponding tetrahedra opposite A,B,C will each have 1/6 the volume of the big one.&lt;/p&gt;&#xA;&lt;p&gt;Now we need to project this point onto the surface ofthe globe.  Work out its distance &lt;span class=&quot;math-container&quot;&gt;$d$&lt;/span&gt; to the origin:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$d^2=(1/12)^2+0^2+((2+\sqrt3)/4)^2=(16+9\sqrt3)/36\approx 0.8775, d\approx 0.9367$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Note that &lt;span class=&quot;math-container&quot;&gt;$d&amp;lt;1$&lt;/span&gt;. Divide this &lt;span class=&quot;math-container&quot;&gt;$d$&lt;/span&gt; into the coordinates of P getting the approximate result&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$P'\approx (0.0890, 0, -0.9960)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Converting back to spherical coordinates then gives a latitude of &lt;span class=&quot;math-container&quot;&gt;$\approx 84.90°=84°54'$&lt;/span&gt; south and longitude zero, the latter due to equally weighting the eastern and western hemispheres in this example.  The interpolated point is more than halfway from the 60° south latitude circle to the South Pole because we interpolated from a distribution of points along this circle rather than a single point; the centroid of of this distribution ( &lt;span class=&quot;math-container&quot;&gt;$\triangle ABC$&lt;/span&gt;) is at more than 60° south latitide.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2020-08-19T18:03:17.390" LastActivityDate="2020-08-19T18:03:17.390" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20075" PostTypeId="1" CreationDate="2020-08-17T00:04:56.350" Score="5" ViewCount="122" Body="&lt;p&gt;The site &lt;a href=&quot;https://spaceweather.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://spaceweather.com/&lt;/a&gt; has a section called Space Weather Balloon Data which shows the image below and says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The data points in the graph above correspond to the peak of the Regener-Pfotzer maximum, which lies about 67,000 feet above central California.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aoHS5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aoHS5.png&quot; alt=&quot;The data points in the graph above correspond to the peak of the Regener-Pfotzer maximum, which lies about 67,000 feet above central California&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Questions:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;What is the Regener-Pfotzer maximum?&lt;/li&gt;&#xA;&lt;li&gt;Why does it occur at 67,000 feet &lt;em&gt;above central California?&lt;/em&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;I have heard of the &lt;a href=&quot;https://space.stackexchange.com/q/20421/12102&quot;&gt;South Atlantic Anomaly&lt;/a&gt; and the &lt;a href=&quot;https://space.stackexchange.com/q/21399/12102&quot;&gt;Equatorial Anomaly&lt;/a&gt; but is there really a radiation anomaly over central California?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2021-04-14T01:28:58.127" LastActivityDate="2021-04-14T01:28:58.127" Title="Why is the Regener-Pfotzer maximum (radiation in upper atmosphere) above central California?" Tags="|earth-observation|atmospheric-radiation|upper-atmosphere|ionizing-radiation|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20076" PostTypeId="1" CreationDate="2020-08-16T20:25:38.000" Score="12" ViewCount="5032" Body="&lt;p&gt;(Please excuse my English)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OLbsP.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OLbsP.gif&quot; alt=&quot;Earth without water&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The picture above is an image of the Earth without water. We know that the picture above is a very exaggerated one. If the Earth were to shrink to the size of the picture above, it would look like a very smooth and round sphere.&lt;/p&gt;&#xA;&lt;p&gt;I wonder what it would look like if the Earth were reduced to the size of a basketball. I think the basketball-sized Earth will have a smoother surface than actual basketball. But I don't know how smooth the surface of the basketball-sized Earth will be.&lt;/p&gt;&#xA;&lt;p&gt;What would the basketball-sized Earth look like? Will it look like a marble ball with shinning smooth surface?&lt;/p&gt;&#xA;" OwnerUserId="20914" OwnerDisplayName="pdh0710" LastEditorUserId="20914" LastEditDate="2020-08-17T15:11:52.407" LastActivityDate="2024-03-06T04:29:56.590" Title="Comparing the Earth with a basketball?" Tags="|earth-observation|" AnswerCount="3" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="20078" PostTypeId="2" ParentId="20076" CreationDate="2020-08-17T00:37:17.667" Score="38" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;The picture above is an image of the Earth without water. We know that the picture above is a very exaggerated one.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;About the image&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;The image shown in the question is very widely claimed to show an image of the Earth without water. A google image search for that image comes up with the nice logo &amp;quot;earth form without water&amp;quot;. This image pops up on the internet again and again. This image does not show an Earth without water, even greatly exaggerated.&lt;/p&gt;&#xA;&lt;p&gt;Note that the image in the question has a fuzzed out title and legend. All of the images on the internet that claim this is an image of the Earth without water have a fuzzed out title and legend. A non-spinning version of that image with the correct title and legend is below. (I do not like reading around animated gifs.)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/m5eh9.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/m5eh9.png&quot; alt=&quot;Exaggerated image of the Earth's geoid height, with legend&quot; /&gt;&lt;/a&gt;&#xA;&lt;sup&gt;Source: Bezděk, Aleš, and Josef Sebera. &amp;quot;Matlab script for 3D visualizing geodata on a rotating globe.&amp;quot; Computers &amp;amp; Geosciences 56 (2013): 127-130.&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;The above image is by the author of the image. The title says what the image shows, which is the geoid height. The legend shows that the variation from the highest to lowest geoid height is less than 200 meters. Compare that with the 19.777 km altitude difference between the highest mountain above sea level and the deepest trench below sea level. The image shows the Tibetan plateau as below the reference ellipsoid and shows the Java trench (not visible in the above) as above the reference ellipsoid. This is not a world without oceans.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;So what does the image show?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;What the image does show is the geoid height, greatly exaggerated. A geoid is the surface of constant gravitational plus centrifugal potential that is the best fit in a least squares sense to mean sea level. In other words, the geoid portrays the Earth's gravitational field. A simpler model of mean sea level is an oblate ellipsoid. The geoid height at some point is the altitude difference between corresponding points on the geoid and on the reference ellipsoid. Red areas in the image (positive geoid height) show where the geoid is above the reference ellipsoid while blue areas (negative geoid height) show where the geoid is below the reference ellipsoid.&lt;/p&gt;&#xA;&lt;p&gt;Look at the Tibet Plateau in the rotating image. It is blue, which means the geoid there is below the reference ellipsoid. Look at the Java Trench. It is the very deepest red, which means the geoid there is above the reference ellipsoid. The Rocky Mountains are white, no different than the rest of the northern North America. The Alps are reddish, but not as red as is the eastern North Atlantic.&lt;/p&gt;&#xA;&lt;p&gt;The Tibet Plateau shows up as a depression in this image instead of as a large elevated land mass because it is are very large blob of rock that has less than average density. The rock near the Java Trench is very dense basalt.&lt;/p&gt;&#xA;&lt;p&gt;The image does not represent anything close to what many say it represents. The image does represent what the author intended it to represent. The image is interesting to those who know what the image portrays. The problem is that the image is so often described incorrectly.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;An image of the Earth without water&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;An image of the Earth without water, slightly exaggerated, is shown below.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Mo0hC.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Mo0hC.jpg&quot; alt=&quot;An image of the Earth with all of it waters gathered into a ball about 1365 km across hovering over the western US&quot; /&gt;&lt;/a&gt;&#xA;&lt;sup&gt;Source: : Jack Cook, Woods Hole Oceanographic Institution, Howard Perlman, USGS, &lt;a href=&quot;https://apod.nasa.gov/apod/ap120515.html&quot; rel=&quot;noreferrer&quot;&gt;Astronomy Picture of the Day 2012 May 15&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;The Earth is round rather than lumpy. For portrayal purposes, a ball of water about 1365 km across hovers over the western US. That ball represents all of the Earth's surface waters.&lt;/p&gt;&#xA;&lt;br&gt;&#xA;&lt;p&gt;&lt;strong&gt;Comparison to a basketball&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;The difference between the Earth's equatorial  and polar radii is about 21.385 km. The difference between the height of the highest mountain on the Earth above sea level and the Earth's deepest trench below sea level is about 19.777 km.&lt;/p&gt;&#xA;&lt;p&gt;Shrinking these down to the size of a basketball with a circumference of 29.5 inches (I used US units because that is what NBA regulations specify) shrinks the 21.385 km difference between the equatorial and polar radii to a mere 0.4 millimeters, shrinks the height of Mount Everest above sea level to 0.165 millimeters, and shrinks the depth Challenger Deep below sea level to 0.204 millimeters.&lt;/p&gt;&#xA;&lt;p&gt;A basketball is supposed to be round(ish). That the Earth's polar radius is 99.66% of its equatorial radius makes the Earth fairly &amp;quot;roundish&amp;quot;. The roundness of the Earth is in line with the roundness of a billiard ball, and probably for a basketball. (While I did find roundness requirements for a billiard ball, I was unsuccessful in finding roundness requirements for a basketball.)&lt;/p&gt;&#xA;&lt;p&gt;What about smoothness? Basketballs are not smooth. They are intentionally designed with stipples (pebbles) and channels so as to make basketballs easier to handle. There are patents galore regarding the size, shape, and placement of those pebbles and channels. The pebbles are a bit higher than 0.17 millimeters and the channels are significantly deeper than 0.2 millimeters. The Earth is smoother than a basketball because basketballs are unsmooth by design.&lt;/p&gt;&#xA;" OwnerUserId="239" OwnerDisplayName="David Hammen" LastEditorUserId="239" LastEditDate="2020-08-20T04:35:09.073" LastActivityDate="2020-08-20T04:35:09.073" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="20079" PostTypeId="2" ParentId="20076" CreationDate="2020-08-17T07:45:54.460" Score="6" Body="&lt;p&gt;The deviations of Earth from a sphere are of order 20 km. This approximates both the difference between equatorial and polar radii (defining an ellipsoid) and the difference between the highest and lowest points (Mount Everest and Mariana Trench) relative to the ellipsoid. A basketball is about 50 million times smaller than Earth, and the corresponding deviations on a basketball would be 0.4 mm.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.productplayoffs.com/best-indoor-basketball/&quot; rel=&quot;noreferrer&quot;&gt;depth&lt;/a&gt; of the main grooves or &amp;quot;ribs&amp;quot; on a real basketball is about 2 mm. I am unable to find a source for the thickness of the numerous bumps or &amp;quot;pebbles&amp;quot; on a real basketball, but it is plausibly close to 0.4 mm. Thus, the bumps that cover the ball are somewhat to scale with the largest 20 km features of Earth, though of course Earth does not have such density of 20 km features.&lt;/p&gt;&#xA;" OwnerUserId="20921" OwnerDisplayName="nanoman" LastActivityDate="2020-08-17T07:45:54.460" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20080" PostTypeId="1" AcceptedAnswerId="20082" CreationDate="2020-08-17T12:44:08.427" Score="1" ViewCount="121" Body="&lt;p&gt;Recently in travelling back to New England I discovered ditches in the lowlands/wetlands of the shoreline on Google Maps satellite view.  They are clearly man-made, but even with all the agriculture and fishing in the area, I cannot figure out the purpose of these.  I have discovered that they seem to be all over New England, but sometimes it's not a.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;What is the purpose of the man-made lines that appear in all these satellite images?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;An example image is below, but it is not very high resolution.  Here are some links that show the phenomenon:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.com/maps/@41.2900598,-72.3288612,2787m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Great Island near Old Lyme, CT&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.com/maps/@41.3351587,-71.8639886,1070m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Near Stonington, CT&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.com/maps/@41.377469,-71.5025261,380m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Marsh near Narraganset, RI&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.com/maps/@41.3360844,-72.3483576,17.23z&quot; rel=&quot;nofollow noreferrer&quot;&gt;Goose Island near Old Saybrook, CT (maps view, not satellite, helps make the lines clear)&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.com/maps/@41.6808413,-70.7616928,590m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Near Marion, MA&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IgGnd.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IgGnd.jpg&quot; alt=&quot;Great Island near Old Lyme CT&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20915" LastActivityDate="2020-08-17T14:12:08.100" Title="Manmade ditches in lowlands of New England" Tags="|geography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20081" PostTypeId="2" ParentId="20063" CreationDate="2020-08-17T13:11:35.733" Score="5" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;But when we look at some diagrams, Earth's atmosphere is thick. For instance, when someone says that the atmosphere is a thin sheet of air, does he/she take in to account the thick layer thermosphere or exosphere? Or is it just that the diagrams we commonly see have inaccurate visual representation?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You are probably referring to diagrams such as this one, dramatically not to scale, yet &lt;a href=&quot;https://www.esa.int/ESA_Multimedia/Images/2018/08/Layers_of_Earth_s_atmosphere&quot; rel=&quot;noreferrer&quot;&gt;from a reputable source&lt;/a&gt; (the European Space Agency):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tWY36.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tWY36.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The only reason these diagrams are not to scale is the sake of readability. They could never fit those fancy planes, balloons and satellites if the diagram was at scale. I've tried: I traced &lt;a href=&quot;https://svgshare.com/i/Nnw.svg&quot; rel=&quot;noreferrer&quot;&gt;this diagram&lt;/a&gt; with Inkscape, using &lt;a href=&quot;https://earthscience.stackexchange.com/a/20064/18081&quot;&gt;Fred's answer&lt;/a&gt; numbers and a 1:100,000,000 scale (on my diagram the Earth has a 6.37 cm radius). I purposely forgot the troposphere line so we could see better. So, from the centre outwards, you have:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Earth's surface.&lt;/li&gt;&#xA;&lt;li&gt;A thick line which represents the top of both the stratosphere and the mesosphere (at 1 pt thickness they are too close to be able to distinguish them).&lt;/li&gt;&#xA;&lt;li&gt;The top of the thermosphere. If you consider this to be the limit then yes, the Earth is like a thick-skinned fruit (grapefruit maybe?).&lt;/li&gt;&#xA;&lt;li&gt;The top of the exosphere.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;It would be pretty hard to squeeze a fancy plane in there, or even a caption to label the layers!&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-08-17T13:11:35.733" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20082" PostTypeId="2" ParentId="20080" CreationDate="2020-08-17T14:12:08.100" Score="3" Body="&lt;p&gt;they are drainage ditches intended to drain salt marshes.&lt;/p&gt;&#xA;&lt;p&gt;They may be old and no longer maintained, it is impossible to tell for certain from satellite but it seems likely.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://qsr.waddensea-worldheritage.org/reports/salt-marshes&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://qsr.waddensea-worldheritage.org/reports/salt-marshes&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2020-08-17T14:12:08.100" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20083" PostTypeId="1" AcceptedAnswerId="20084" CreationDate="2020-08-17T17:23:31.597" Score="1" ViewCount="186" Body="&lt;p&gt;As far as I know, heat waves form when a high-pressure system builds up over an area. This forms a sort of &amp;quot;cap&amp;quot; over the affected area which prevents air from rising and cooling and then coming back to the surface. This results in a continuous buildup of heat leading to a heatwave. When a heatwave ends, I'm assuming that means the high-pressure system mixes with another low-pressure system. When two systems like these mix and there is moisture I believe thunderstorms are likely to form.&lt;/p&gt;&#xA;&lt;p&gt;My question is if this reasoning is correct and if thunderstorms are common after a heatwave ends in areas where there is some moisture in the air at the end of the heatwave.&lt;/p&gt;&#xA;&lt;p&gt;In other words, what exactly happens in the atmosphere when a heatwave needs and would this lead to increased chance of thunderstorms in areas where the air has some moisture?&lt;/p&gt;&#xA;" OwnerUserId="20918" LastActivityDate="2020-08-18T17:35:56.757" Title="Are thunderstorms normal at the end of a heat wave?" Tags="|meteorology|thunderstorm|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20084" PostTypeId="2" ParentId="20083" CreationDate="2020-08-17T19:25:16.953" Score="5" Body="&lt;p&gt;Ingredients necessary for the formation of thunderstorms are&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;... moisture, rising unstable air (air that keeps rising when given a nudge), and a lifting mechanism to provide the “nudge.” (&lt;a href=&quot;https://www.nssl.noaa.gov/education/svrwx101/thunderstorms/&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;as well as&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;... MOISTURE, INSTABILITY, and LIFTING. Additionally, there is a fourth ingredient (WIND SHEAR) ... (&lt;a href=&quot;https://www.weather.gov/source/zhu/ZHU_Training_Page/thunderstorm_stuff/Thunderstorms/thunderstorms.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and they depend on the local, regional or overregional weather situation, can have seasonal aspects, may be be bound to one or more circulation patterns or just depend on the weather ;-)&lt;/p&gt;&#xA;&lt;p&gt;Thunderstorms can form &lt;em&gt;isolated&lt;/em&gt;, e.g. in the afternoon when during the day the conditions have built up and &lt;em&gt;labilization&lt;/em&gt; took place from different ground types, orography, sunshine duration/intensity/angle or &amp;quot;drops&amp;quot; of cold air high up in the troposphere. These are &lt;a href=&quot;https://scied.ucar.edu/learning-zone/storms/thunderstorms&quot; rel=&quot;nofollow noreferrer&quot;&gt;Orograhic thunderstorms or air mass thunderstorms&lt;/a&gt;. They are usually (but not always) short lived (hours), local and occur in the afternoon and last until the early night.&lt;/p&gt;&#xA;&lt;p&gt;Or thunderstorms can form along a &lt;em&gt;frontal line&lt;/em&gt; that separates cold from warm air mass and that moves into the warm, moist air, causing it to rise to great height where it starts to condensate. This phenomenon is called a &lt;a href=&quot;https://en.wikipedia.org/wiki/Cold_front&quot; rel=&quot;nofollow noreferrer&quot;&gt;cold front&lt;/a&gt; or in a special form a squall line (&lt;a href=&quot;https://www.nssl.noaa.gov/education/svrwx101/thunderstorms/types/&quot; rel=&quot;nofollow noreferrer&quot;&gt;radar image&lt;/a&gt;) and labilization is here the result of the difference in air temperature and moisture on a relatively narrow frontal line. Frontal system have considerable length (100s or rarely thousands of km) and moves swiftly over long distances. These frontal systems can be part of the cylones in the temperate zones (not the tropical cyclones, those are different and I leave them out here, though they house embedded thunderstorms as well) and move with the prevailing western drift there. Such a frontal passage usually doesn't last long, comes with a significant drop in air temperature when passing overhead and a significant weather change and veering wind, on the northern hemisphere.&lt;/p&gt;&#xA;&lt;p&gt;All these forms are expressions of &lt;a href=&quot;https://www.metoffice.gov.uk/weather/learn-about/weather/how-weather-works/what-is-convection&quot; rel=&quot;nofollow noreferrer&quot;&gt;convective&lt;/a&gt; weather, vertical movement of air caused by labilization.&lt;/p&gt;&#xA;&lt;p&gt;Otoh, heat waves are frequently simply the result of dry and hot air being transported by &lt;a href=&quot;https://www.weatheronline.co.uk/reports/wxfacts/Advection.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;advection&lt;/a&gt;, which is not bound to a local scale alone. For example the Sahara air to central Europe. This air is hot and very dry, and it simply lasts until the weather situation changes and different airmasses come along, e.g. of Atlantic origin. There won't be thunderstorms, then, because there's not enough moisture. Such a weather situation frequently happens on the Canaries (just as an example), it leads to a hot and extremely dry atmosphere until great height, with a cool layer underneath, for example 23°C at sea level, ~30° at 500m ASL with an inversion in between, and 35°C around the summits between 2,000 and 2,500m ASL. This is absolutely stable and not even slightly conducive for the formation of convection or any kind of precipitation (except sand :-/).&lt;/p&gt;&#xA;&lt;p&gt;tl.dr: No, it is not normal, but it can happen. There is no general rule and it is not the absolute temperature that causes thunderstorms, but differences in temperature and moisture that cause labilization and thus convection.&lt;/p&gt;&#xA;" OwnerDisplayName="user20217" LastEditorDisplayName="user20217" LastEditDate="2020-08-18T08:38:29.553" LastActivityDate="2020-08-18T08:38:29.553" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20085" PostTypeId="1" AcceptedAnswerId="20098" CreationDate="2020-08-17T19:46:36.687" Score="1" ViewCount="75" Body="&lt;p&gt;From what I read all over the web and articles, drainage density is a parameter that is defined for a catchment.&lt;/p&gt;&#xA;&lt;p&gt;I want to use a hydrological model to simulate the percolation from the bottom of a soil column, therefore my spatial scale is point-scale.&lt;/p&gt;&#xA;&lt;p&gt;This model both works in point-scale mode and distributed mode. In the point-scale, I still need to choose a value for the drainage density (DD).&lt;/p&gt;&#xA;&lt;p&gt;As described in this &lt;a href=&quot;https://onlinelibrary.wiley.com/doi/full/10.1002/esp.3884&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt; :&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ DD = \dfrac{1}{2 HL} ,$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$HL$&lt;/span&gt; is the length of hillslope.&lt;/p&gt;&#xA;&lt;p&gt;Any idea how to calculate &lt;span class=&quot;math-container&quot;&gt;$HL$&lt;/span&gt; for a soil column?&lt;/p&gt;&#xA;&lt;p&gt;Can I say &lt;span class=&quot;math-container&quot;&gt;$HL$&lt;/span&gt; is equal to the depth of the soil column (surface to the seepage face)?&lt;/p&gt;&#xA;&lt;p&gt;Or it doesn't make sense to define DD in the point-scale?&lt;/p&gt;&#xA;&lt;p&gt;In this model, DD affects the ratio of &lt;span class=&quot;math-container&quot;&gt;$\dfrac{lateral flow}{percolation}$&lt;/span&gt;. As for the lateral flow in the soil column, beside the topographical slope and soil textures, is there any other parameters that is important to consider?&lt;/p&gt;&#xA;&lt;p&gt;Please let me know if I did not explain my question clearly.&lt;/p&gt;&#xA;" OwnerUserId="20807" LastEditorUserId="20807" LastEditDate="2020-08-17T19:54:18.457" LastActivityDate="2020-09-19T16:05:25.500" Title="Can we define &quot;drainage density&quot; for a soil column (point-scale)?" Tags="|hydrology|hydrogeology|land-surface|soil-science|land-surface-models|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20086" PostTypeId="2" ParentId="20076" CreationDate="2020-08-18T00:13:08.463" Score="1" Body="&lt;p&gt;A basketball is a &lt;em&gt;&lt;strong&gt;sphere&lt;/strong&gt;&lt;/em&gt; while Earth is an &lt;em&gt;&lt;strong&gt;oblate spheroid&lt;/strong&gt;&lt;/em&gt;, meaning Earth's equatorial radius is larger than its polar radius (as mentioned already in &lt;a href=&quot;https://earthscience.stackexchange.com/a/20078/18946&quot;&gt;David Hammen's answer&lt;/a&gt; and &lt;a href=&quot;https://earthscience.stackexchange.com/a/20079/18946&quot;&gt;nanoman's answer&lt;/a&gt;, I have just introduced the &lt;em&gt;name&lt;/em&gt; for this phenomenon).&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;What exactly is an &lt;a href=&quot;https://en.wikipedia.org/wiki/Spheroid&quot; rel=&quot;nofollow noreferrer&quot;&gt;oblate spheroid&lt;/a&gt;?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;If you take an ellipse and rotate it around its major (longer) axis you get a prolate spheroid, much like an Australian football:&lt;/p&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/E0rG2.png&quot; height=&quot;150&quot;&gt;&#xA;&lt;p&gt;If you rotate the ellipse around its minor (shorter) axis, you get an oblate spheroid, more like a lentil, M&amp;amp;M chocolate, or mandarin fruit:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/j4qQI.png&quot; height=&quot;200&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dFd4z.png&quot; height=&quot;200&quot;&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here are the oblate and prolate spheroids side-by-side:&lt;/p&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/3kjAS.png&quot; width=&quot;500&quot;&gt;&#xA;&lt;p&gt;This is a sphere:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/v6YIr.png&quot; width=&quot;250&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uIyrU.png&quot; width=&quot;300&quot;&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Earth is an oblate spheroid, so a basketball is not the best model. A mandarin fruit is better.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="18946" LastActivityDate="2020-08-18T00:13:08.463" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="20087" PostTypeId="2" ParentId="20083" CreationDate="2020-08-18T17:35:56.757" Score="1" Body="&lt;p&gt;Q: Are thunderstorms normal at the end of a heatwave?&lt;/p&gt;&#xA;&lt;p&gt;Depends on how quickly cooler weather moves in and how moist it is.&lt;/p&gt;&#xA;&lt;p&gt;If it's hot and a cooler damper mass of air moves in quickly (over a couple of hours) - yeeha! thunderstorms.&lt;/p&gt;&#xA;&lt;p&gt;if it's hot and cooler weather moves in over multiple days - probably not.&lt;/p&gt;&#xA;&lt;p&gt;:)&lt;/p&gt;&#xA;" OwnerUserId="20871" LastActivityDate="2020-08-18T17:35:56.757" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20088" PostTypeId="1" CreationDate="2020-08-18T17:45:28.290" Score="1" ViewCount="314" Body="&lt;p&gt;Imagine two points, one directly above the other.&#xA;&lt;br&gt;Point A - 10,000 feet (PA)&#xA;&lt;br&gt;Point B - 20,000 feet (PB)&lt;/p&gt;&#xA;&lt;p&gt;Imagine there's voltage potential between those two points.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Questions&lt;/strong&gt;:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;How could you measure the voltage between those to points?&lt;/li&gt;&#xA;&lt;li&gt;What if the points were at the same altitude, but 10 miles away from&#xA;each other. How could you measure the voltage potential? (i.e. PA is&#xA;in Ohio at 10k feet and PB is in Indiana at 20k feet altitude -&#xA;ground distance between the two points is 10 miles)&lt;/li&gt;&#xA;&lt;li&gt;How could you determine if the potential was oscillating?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="20871" LastEditorUserId="21206" LastEditDate="2023-01-07T11:46:22.277" LastActivityDate="2023-10-04T13:07:05.880" Title="How to measure voltage differential across different altitudes" Tags="|meteorology|atmosphere|lightning|electromagnetism|stratosphere|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20089" PostTypeId="2" ParentId="20088" CreationDate="2020-08-18T20:54:48.797" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;How could you measure the voltage between those to points?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I imagine you could measure the potential difference using weather balloons. Send one balloon up to 10,000 ft (Balloon A) and one to 20,000 ft (Balloon B) with wires connecting them to a voltmeter. The challenge here is to account for the wire resistance, which, if the potential difference is low, will in all likelihood interfere with the measurement. If the difference is too low to be measured, you would have to amplify the voltage and then account for the amplification and wire resistance.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;What if the points were at the same altitude, but 10 miles away from each other. How could you measure the voltage potential? (i.e. PA is in Ohio at 10k feet and PB is in Indiana at 20k feet altitude - ground distance between the two points is 10 miles)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I would try using weather balloons again, but obviously Balloon A and Balloon B would be at the same altitude but 10 miles apart from each other.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;How could you determine if the potential was oscillating?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Instead of a voltmeter measure with an oscilloscope. There's going to be noise no matter what; what oscillations are produced by noise and what is actual oscillations is a judgment call. I would say that truly oscillating potential difference is likely to be low frequency, so to filter out high frequency noise connect the circuit to a low-pass filter before processing with the oscilloscope.&lt;/p&gt;&#xA;&lt;p&gt;Another way to determine oscillations is to measure the voltage with a data logger and post-process with computer software; any programming language that can easily manipulate large amounts of data would be sufficient, even excel would work. Plot the voltage vs time using a linear regression model to smooth the noise out. As an example, python's numpy has a regression function called polyfit. With a linear regression model and a moving window you will truncate the beginning and end of the dataset, but that shouldn't matter if you have a lot of data.&lt;/p&gt;&#xA;" OwnerUserId="20928" LastEditorUserId="21206" LastEditDate="2023-01-07T11:46:13.670" LastActivityDate="2023-01-07T11:46:13.670" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20090" PostTypeId="1" AcceptedAnswerId="20091" CreationDate="2020-08-19T16:34:37.110" Score="1" ViewCount="413" Body="&lt;p&gt;I have bought this &lt;a href=&quot;https://proto-pic.co.uk/product/weather-meter-kit-sparkfun-sen-15901/&quot; rel=&quot;nofollow noreferrer&quot;&gt;cheap rain gauge&lt;/a&gt; (only the rain gauge, not the other parts) for measuring rainfall with a Raspberry Pi. It works as far as I can tell, every bucket swing will result in an interrupt that I can further process.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://cdn.sparkfun.com/assets/d/1/e/0/6/DS-15901-Weather_Meter.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;datasheet&lt;/a&gt; is located here and this is where my questions begin:&lt;/p&gt;&#xA;&lt;p&gt;I have calibrated the device and found that around 1.2-1.3 mL will tip the bucket. Now rainfall is usually measured in mm/m², so the datasheet also covers this: &lt;code&gt;0.2794mm&lt;/code&gt; per contact. Now how do I get this to a measurement in mm/m²? The area of the rain gauge is about ~0.0055m² (11x5cm). Is it safe to assume that the rainfall is the same in this m²? So if I measure 5mm of rainfall, then it's also 5mm per m²?&lt;/p&gt;&#xA;&lt;p&gt;Hope that was not too complicated in my explanation.&lt;/p&gt;&#xA;" OwnerUserId="20932" LastEditorUserId="20932" LastEditDate="2020-08-19T16:41:22.037" LastActivityDate="2020-08-19T23:11:58.787" Title="Tipping bucket rain gauge measurement, normalizing" Tags="|measurements|rainfall|rain|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20091" PostTypeId="2" ParentId="20090" CreationDate="2020-08-19T18:47:08.463" Score="1" Body="&lt;p&gt;mm per square meter is a measurement of volume, it's not really a depth divided by an area. You can tell as much because if you have 1 mm per square meter and you increase the coverage area to 2 square meters, the depth doesn't change---the volume increases. You just need to convert your volume measurement.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;1.2 mL = 1.2 cm^{3}&#xA;$$&lt;/span&gt;&#xA;1.2 cubic centimeters is equivalent to a 1.2 cm depth over an area of 1 square cm.&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;1.2 cm = 12 mm&#xA;$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;1 cm^{2} * \frac{1 m^{2}}{100^{2} cm^{2}} = 0.0001m^{2}&#xA;$$&lt;/span&gt;&#xA;12mm per 0.0001 square meters is not a useful metric. You have to obviously make the square meters 1 square meter, but you have to be careful. When you increase the area, the depth will necessarily decrease (because the volume has to be equivalent). Multiplying the area by 10,000 square meters per square meter will give you 1 square meter; subsequently, the depth must be divided by the same amount.&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\frac{12mm}{10,000} = 0.0012 mm&#xA;$$&lt;/span&gt;&#xA;So you have 0.0012 mm per square meter with each tip of the rain gauge. We can check our work by converting it back to a normal volume.&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;0.0012 mm * 1 m^{2} * \frac{1000^{2} mm^{2}}{1 m^{2}} = 1200 mm^{3} = 1.2 mL&#xA;$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;As a side note, here is a useful tool provided by the United States Geological Survey for converting depth per area measurements to equivalent volumes:&#xA;&lt;a href=&quot;https://water.usgs.gov/edu/activity-howmuchrain-metric.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://water.usgs.gov/edu/activity-howmuchrain-metric.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Going back to the depth given by the data sheet, I ran the numbers and&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;(0.2794mm)/(1000mm/m)*(0.0055m^2) \approx 1.54 mL&#xA;$$&lt;/span&gt;&#xA;which about matches the volume you have. So if you want the depth for one square meter, you just have to multiply the area by the factor of &lt;span class=&quot;math-container&quot;&gt;$\frac{1m^{2}}{0.0055m^{2}}$&lt;/span&gt; and divide the depth by the same factor. So essentially you want to multiply the depth by the catchment area of the gauge.&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;(0.2794 mm) * (0.0055 m^2/m^2) = 0.00154 mm&#xA;$$&lt;/span&gt;&#xA;as the depth for 1 square meter.&lt;/p&gt;&#xA;" OwnerUserId="20928" LastEditorUserId="20928" LastEditDate="2020-08-19T23:11:58.787" LastActivityDate="2020-08-19T23:11:58.787" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="20092" PostTypeId="1" CreationDate="2020-08-19T21:57:48.220" Score="1" ViewCount="138" Body="&lt;p&gt;What would be the phase shift and polarity of a seismic wave a) when it hit the free surface&#xA;b)when the free surface reflection goes down and hit a reflector and returned to the receiver placed on the surface.&lt;/p&gt;&#xA;" OwnerUserId="20935" LastActivityDate="2020-08-21T05:50:10.050" Title="What would be the phase shift and polarity of a seismic wave upon reflection" Tags="|geophysics|seismology|seismic|waves|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20097" PostTypeId="2" ParentId="20052" CreationDate="2020-08-20T11:44:11.313" Score="2" Body="&lt;p&gt;There are at least 2 books that come to mind:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/1426310382&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Geographic Readers: Rocks and Minerals (2012)&lt;/a&gt;, a richly illustrated guide for kids.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/1426323018&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ultimate Explorer Field Guide: Rocks and Minerals (2016)&lt;/a&gt; by Nancy Honovich, a guide focussed on getting kids outside, looking at rocks in their backyards and on the camping.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Considering you're in the UK, afterwards I'd start with some experiments about limestone. National Geographic used to have rock kits for kids, not sure who else sells them near you. With the keywords &amp;quot;rock kit kids uk&amp;quot; I get some results that may be worth a look at.&lt;/p&gt;&#xA;" OwnerUserId="1403" LastActivityDate="2020-08-20T11:44:11.313" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20098" PostTypeId="2" ParentId="20085" CreationDate="2020-08-20T15:13:56.930" Score="2" Body="&lt;p&gt;Fundamentally it doesn't make sense to describe the point scale model with hillslope length and drainage density. If you are looking to model a soil column, you could use Darcy's law or Richard's equation. If you are looking to model the catchment, the point scale is not appropriate, although you could always incorporate those point-scale appropriate equations into a more complete hydrologic model if you wish (something like HydroGeoSphere does), but that is still a catchment scale model.&lt;/p&gt;&#xA;&lt;p&gt;In either case, this comes back to 1) what is the purpose of your modelling exercise, and 2) making sure that your choice of model is appropriate for that purpose. A hydrologic model that uses hillslope length for a point scale is not an appropriate choice for what (I think) you are trying to do.&lt;/p&gt;&#xA;" OwnerUserId="8440" LastActivityDate="2020-08-20T15:13:56.930" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20099" PostTypeId="1" CreationDate="2020-08-21T02:44:12.197" Score="1" ViewCount="146" Body="&lt;p&gt;Given the differences in temperature, salinity and elevation between the Pacific &amp;amp; Atlantic oceans, what would happen to the Gulf Stream and thus the weather in western Europe and also the eastern seaboard of North America if the isthmus between North and South America were to no longer exist, for whatever reason?&lt;/p&gt;&#xA;" OwnerUserId="20937" LastEditorUserId="2470" LastEditDate="2020-08-21T10:51:58.227" LastActivityDate="2020-08-22T14:48:55.927" Title="If the Isthmus between North &amp; South America did not exist what would happen to the Gulfstream and thus the weather in Western Europe?" Tags="|weather-forecasting|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="20100" PostTypeId="2" ParentId="20092" CreationDate="2020-08-21T05:50:10.050" Score="1" Body="&lt;p&gt;In general, the answer is not simple as it depends on the angle of incidence of the wave and the properties of the medium.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Zoeppritz_equations&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zoeppritz equations&lt;/a&gt; are used to understand the behavior of seismic waves incident on reflectors (or the free surface). The solutions give the reflection and transmission coefficients for P and S waves, which depend on the densities and wave speeds of the lower and upper media as well as the angle upon which the wave is incident. In general, the coefficients are complex valued; the phase shift is encoded in the phase of the complex number.&lt;/p&gt;&#xA;&lt;p&gt;I have used the &lt;a href=&quot;https://www.crewes.org/ResearchLinks/ExplorerPrograms/ZE/ZEcrewes2_2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zeoppritz explorer program&lt;/a&gt; for this calculation.&lt;/p&gt;&#xA;" OwnerUserId="18386" LastActivityDate="2020-08-21T05:50:10.050" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20102" PostTypeId="1" CreationDate="2020-08-21T17:32:17.617" Score="0" ViewCount="198" Body="&lt;p&gt;I hear all the arguments one explains to a flat earther as to why the earth is Spherical and not flat. I am not a meteorologist, but I know enough Meteorology for me to fly safely as a pilot. Getting deeper, doesn't Meteorology rely on a spherical model? If yes, then why? I don't think a flat earth could maintain such an incredible, intricate system on a disc anyways.&lt;/p&gt;&#xA;&lt;p&gt;I point out only disc because we have people who believe in a flat earth. I've never heard anyone explain to a flat earther why or how important meteorlogy relies on a spherical model for weather to work. I, myself, is interested in the nitty-gritty of the very mechanism that runs our weather which happens to involve the shape of our world.&lt;/p&gt;&#xA;" OwnerUserId="20941" LastEditorUserId="20941" LastEditDate="2020-08-22T06:13:26.937" LastActivityDate="2020-08-22T06:13:26.937" Title="Why does Meteorology rely on a spherical model of the earth, rather than a flat earth, to function?" Tags="|meteorology|geophysics|geography|earth-rotation|earth-system|" AnswerCount="1" CommentCount="9" ClosedDate="2020-08-22T08:02:43.970" ContentLicense="CC BY-SA 4.0" />
  <row Id="20103" PostTypeId="2" ParentId="20102" CreationDate="2020-08-21T18:12:57.727" Score="6" Body="&lt;p&gt;Meteorology relies heavily on a spherical model of the earth. If you consider one of the major &amp;quot;forces,&amp;quot; the Coriolis force, it is derivable only from a spherical earth.&lt;/p&gt;&#xA;&lt;p&gt;Now, there are planar representations, where the earth's curvature has a negligible effect, such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Mesoscale_meteorology#:%7E:text=Mesoscale%20meteorology%20is%20the%20study,kilometers%20to%20several%20hundred%20kilometers.&quot; rel=&quot;noreferrer&quot;&gt;mesoscale&lt;/a&gt; meteorology or &lt;a href=&quot;https://en.wikipedia.org/wiki/Microscale_meteorology&quot; rel=&quot;noreferrer&quot;&gt;micrometeorology&lt;/a&gt;. A sphere also has modeling advantages for &lt;a href=&quot;https://www.e-education.psu.edu/worldofweather/node/2112#:%7E:text=It%20turns%20out%20there%20is,...%20a%20spectral%20model.&amp;amp;text=A%20spectral%20model%20first%20approximates,the%20%22sine%22%20are%20used.&quot; rel=&quot;noreferrer&quot;&gt;spectral models&lt;/a&gt;, since a wave is easily represented on the sphere as a &lt;a href=&quot;https://mathworld.wolfram.com/SphericalHarmonic.html&quot; rel=&quot;noreferrer&quot;&gt;spherical harmonic&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Now for mental models, sometimes it is useful to make an &lt;a href=&quot;https://en.wikipedia.org/wiki/F-plane#:%7E:text=In%20geophysical%20fluid%20dynamics%2C%20the,of%20highly%20idealized%20tropical%20cyclones.&quot; rel=&quot;noreferrer&quot;&gt;f-plane&lt;/a&gt; approximation or even a &lt;a href=&quot;https://en.wikipedia.org/wiki/Beta_plane&quot; rel=&quot;noreferrer&quot;&gt;beta plane approximation&lt;/a&gt;. But that only happens for dynamics. Moreover, the change in radiation with latitude is highly dependent on the angle on the face of the earth with respect to the sun.&lt;/p&gt;&#xA;&lt;p&gt;All of this to say is that the earth is technically an &lt;a href=&quot;https://en.wikipedia.org/wiki/Figure_of_the_Earth&quot; rel=&quot;noreferrer&quot;&gt;oblate elipsoid&lt;/a&gt;, a sphere is a sufficient approximation to reality. So we use what is closer to reality as to be meaningful, but abstract enough that differences from reality are confined to the very nitty gritty. A disk has no 3-D qualities to it- a relic of flat-earthers- and is not representative of reality.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-08-21T18:12:57.727" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20104" PostTypeId="2" ParentId="1092" CreationDate="2020-08-21T18:14:15.637" Score="3" Body="&lt;p&gt;ASOS data for all the airports in the world:&#xA;&lt;a href=&quot;https://mesonet.agron.iastate.edu/request/download.phtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://mesonet.agron.iastate.edu/request/download.phtml&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This website also has a lot of other meteorological data for the United States.&lt;/p&gt;&#xA;" OwnerUserId="15197" LastActivityDate="2020-08-21T18:14:15.637" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20105" PostTypeId="2" ParentId="20052" CreationDate="2020-08-22T08:22:46.747" Score="1" Body="&lt;p&gt;What a nice question! There is not a whole lot of literature on geology aimed at children but it is a great subject to get interested in (OK, I am biased). A quick Amazon search suggests &amp;quot;The Street beneath our Feet&amp;quot; by Charlotte Guillard is very well thought of as a starter - and she is an English author. Of more grown up books which could provide inspiration for a an enthusiastic kid I would suggest The Hidden Landscape by Richard Fortey, The Geology of Britain by Peter Toghill , The illustrated Guide to Rocks and minerals by John Farndon.&#xA;Mary Anning is of course the great british pioneering female role-model and well worth using to help inspire your daughter - not least since there are two films getting close to release based on her story. She has also inspired authors so there are plenty of books to choose from at different levels. Once you have learnt a bit you are perfectly placed to follow up by visiting the NHM in London to see specimens she collected and to visit Lyme Regis to start collecting your own. If you do then make sure to visit the Philpott Museum in Lyme and to go on a guided fossil hunting walk - the best ones are organised by the museum and by Charmouth Heritage centre. On the way back go to Kimmeridge to visit the amazing new museum of Steve Etches' fossils.&#xA;There is also a lot of good geology on your doorstep - The Weald is one of the best places to explore the relationship between landscape and geology. I don't think there are any good books for children but you can get copies of the Geological Survey handbook or the New Naturalist book (ancient but a classic) to research the basics (Chalk/Downs, Gault Clay/ Vale of Holmesdale, Greensand Ridge (eg Box Hill)/Lower Greensand, Low Weald/Weald Clay (dinosaurs), High Weald / Wealden Sandstone (e.g Ashdown Forest, Wellington Rocks in Tunbridge Wells) then drive south to explore it.&#xA;Finally don't forget the Isle of Wight.&lt;/p&gt;&#xA;" OwnerUserId="17018" LastActivityDate="2020-08-22T08:22:46.747" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20106" PostTypeId="2" ParentId="20052" CreationDate="2020-08-22T09:47:40.123" Score="0" Body="&lt;p&gt;I'd splash out and buy 50 A4 sized books on science and nature and history: Astronomy, Stars, Human body, Insects, Rocks, Gemstones, inventions, all for 6-12 year olds, with big pretty pictures and informative texts.&lt;/p&gt;&#xA;&lt;p&gt;Most of these books cost 1-2 dollars to buy and have plenty of reviews:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.amazon.co.uk/s?k=minerals&amp;amp;rh=n%3A69&amp;amp;ref=nb_sb_noss&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.amazon.co.uk/s?k=minerals&amp;amp;rh=n%3A69&amp;amp;ref=nb_sb_noss&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.amazon.co.uk/s?k=earth&amp;amp;rh=n%3A69&amp;amp;ref=nb_sb_noss&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.amazon.co.uk/s?k=earth&amp;amp;rh=n%3A69&amp;amp;ref=nb_sb_noss&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.amazon.co.uk/s?k=volcanos&amp;amp;rh=n%3A69&amp;amp;ref=nb_sb_noss&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.amazon.co.uk/s?k=volcanos&amp;amp;rh=n%3A69&amp;amp;ref=nb_sb_noss&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.amazon.co.uk/s?k=planet&amp;amp;rh=n%3A69&amp;amp;ref=nb_sb_noss&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.amazon.co.uk/s?k=planet&amp;amp;rh=n%3A69&amp;amp;ref=nb_sb_noss&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.amazon.co.uk/s?k=fossils&amp;amp;rh=n%3A69&amp;amp;ref=nb_sb_noss&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.amazon.co.uk/s?k=fossils&amp;amp;rh=n%3A69&amp;amp;ref=nb_sb_noss&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I don't think a kids home without 100 science and learning books would be fair on the kids. I'd devote 1 meter by 1 meter at least for it. She will probably change her mind and pick some other interests as a result! Make sure you get the big books for kids, little books are fiddly and made for travel.&lt;/p&gt;&#xA;&lt;p&gt;At my local flea market shop I think i can get 10 books for a 5er.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastActivityDate="2020-08-22T09:47:40.123" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20108" PostTypeId="1" CreationDate="2020-08-22T17:01:53.720" Score="3" ViewCount="898" Body="&lt;p&gt;I've been searching for a map depicting the age of each part of the crust for a long time. I'm not a geologist but I'm a physicist so I would like to know about the most up-to-date and accurate references possible.&lt;/p&gt;&#xA;&lt;p&gt;Since this is not my field I would like to know if these are &amp;quot;old models&amp;quot; now; &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007GC001743&quot; rel=&quot;nofollow noreferrer&quot;&gt;Müller et al. (2008)&lt;/a&gt; gave an age model for the oceanic crust and the relevant revised data &lt;a href=&quot;http://www.earthbyte.org/age-spreading-rates-and-spreading-asymmetry-of-the-worlds-ocean-crust/&quot; rel=&quot;nofollow noreferrer&quot;&gt;can be downloaded&lt;/a&gt; from earthbytes.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JSGWJ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JSGWJ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But models for the continental crust age seem to be less reliable (lower spatial resolution, less resolution in the time domain and less coherent sources blended toghether). I've found this one from &lt;a href=&quot;http://www.lithosphere.info/papers/2006-Tecto-Art-TC1-small.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Irina M. Artemieva (2005)&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VPhqQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VPhqQ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But there are two main problems with this map: 1) I'm unable to find the dataset anywhere and 2) between Müller's and Irina's maps there are missing parts (submerged continental crust like in Zelandia or the arctic) from which I would like to know the age also.&lt;/p&gt;&#xA;&lt;p&gt;In short:&#xA;I would like to know if there's a coherent global map of the age of the crust, with no regional gaps and up-to-date. It would be great if the data can be downloaded so I can visualize it myself with python or something similar. If there are no maps like that then I would like the best possible maps of the age of the continental crust so I can blend it with the Müller's map.&lt;/p&gt;&#xA;&lt;p&gt;Thank you in advance.&lt;/p&gt;&#xA;" OwnerUserId="18279" LastEditorUserId="18279" LastEditDate="2020-08-22T17:07:22.313" LastActivityDate="2022-04-02T06:37:12.480" Title="Crustal age global map" Tags="|geology|mapping|crust|paleogeography|age|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20110" PostTypeId="1" AcceptedAnswerId="20111" CreationDate="2020-08-23T12:34:38.117" Score="41" ViewCount="10487" Body="&lt;p&gt;I saw this graph about the global temperature, it goes back for 2000 years.&lt;/p&gt;&#xA;&lt;p&gt;How is it possible to measure temperature 2000 years back &lt;strong&gt;with such a precision&lt;/strong&gt; of like ~0.1 C?&lt;/p&gt;&#xA;&lt;p&gt;The image from &lt;a href=&quot;https://www.reddit.com/r/dataisbeautiful/comments/ickvfq/oc_two_thousand_years_of_global_temperatures_in/&quot; rel=&quot;noreferrer&quot;&gt;Reddit post&lt;/a&gt; I don't know the source of original data.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;What tools are used to measure it?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gilfy.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gilfy.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20947" LastEditorUserId="20947" LastEditDate="2020-08-24T23:29:03.570" LastActivityDate="2020-09-03T14:53:20.760" Title="How it's possible to measure temperature 2000 years ago with such precision?" Tags="|temperature|paleoclimatology|" AnswerCount="2" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="20111" PostTypeId="2" ParentId="20110" CreationDate="2020-08-23T14:43:48.303" Score="55" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;How it's possible to measure temperature 2000 years ago?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Sans the technology used by Bill and Ted (&amp;quot;Bill and Ted's Excellent Adventure&amp;quot;), it obviously is not possible to directly measure the temperature from yesterday, let alone 2000 years ago, or longer. What is used are &amp;quot;proxies&amp;quot;, things that can be measured today that serve as stand-ins for things such as temperature in the past.&lt;/p&gt;&#xA;&lt;p&gt;One example of a proxy is the amount of oxygen-18 in the ice in Greenland and Antarctica. Water with two hydrogen atoms and one oxygen-16 atom has a boiling point of about 100° C. Water with the oxygen-16 atom replaced by an oxygen-18 atom has a slightly higher boiling point. This means that heavy oxygen water evaporates less readily but precipitates more readily than does normal water.&lt;/p&gt;&#xA;&lt;p&gt;This in turn means that the fraction of oxygen 18 versus oxygen 16 in the water and air bubbles in the ancient ice in Greenland and Antarctica are indicative of the climate at the time that that ice and those air bubbles formed. Despite being a half a world apart, the ratios of oxygen-18 to oxygen-16 over time are highly consistent between Greenland and Antarctica. The consistency of these measures at half a world apart are almost universally taken as being a proxy for something else, and that something else is climate.&lt;/p&gt;&#xA;&lt;p&gt;There are many other proxies for past climate. There are other isotopes that serve as proxies. The amounts and kinds of pollen in mountain glaciers and ice sheets form yet another kind of proxy. The kinds of plants that do grow in some locales and how fast they do grow is highly temperature dependent. Like ice, buried muds in the oceans also show variations in various proxies. Climate scientists put these proxy measurements together to arrive at the temperatures from 2000 years ago, and even further into the past.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-08-23T14:43:48.303" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="20112" PostTypeId="2" ParentId="16577" CreationDate="2020-08-23T17:05:30.503" Score="2" Body="&lt;p&gt;Besides man-made sources, hydrogen can be produced naturally through a process called &lt;strong&gt;serpentization&lt;/strong&gt;.  Mafic and ultramafic rocks, which are rich in magnesium and iron silicates, react with water to produce a variety of breakdown products summarized in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Serpentinite#&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia article on serpentine&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Serpentinization is a geological low-temperature metamorphic process involving heat and water in which low-silica mafic and ultramafic rocks are oxidized (anaerobic oxidation of Fe&lt;sup&gt;2+&lt;/sup&gt; by the protons of water leading to the formation of H&lt;sub&gt;2&lt;/sub&gt;) and hydrolyzed with water into serpentinite. Peridotite, including dunite, at and near the seafloor and in mountain belts is converted to serpentine, brucite, magnetite, and other minerals — some rare, such as awaruite (Ni&lt;sub&gt;3&lt;/sub&gt;Fe), and even native iron. In the process large amounts of water are absorbed into the rock increasing the volume, reducing the density and destroying the structure.[1]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The density changes from 3.3 to 2.7 g/cm&lt;sup&gt;3&lt;/sup&gt; with a concurrent volume increase on the order of 30-40%. The reaction is highly exothermic and rock temperatures can be raised by about 260 °C (500 °F),[1] providing an energy source for formation of non-volcanic hydrothermal vents. The magnetite-forming chemical reactions produce hydrogen gas under anaerobic conditions prevailing deep in the mantle, far from the Earth's atmosphere. Carbonates and sulfates are subsequently reduced by hydrogen and form methane and hydrogen sulfide. The hydrogen, methane, and hydrogen sulfide provide energy sources for deep sea chemotroph microorganisms.[1]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Roughly speaking, the magnesium-bearing component of the mafic/ultramafic rock is basic and undergoes acid-base reactions with water, generating no hydrogen (but possibly producing magnesium hydroxide, which indicates said basic conditions).  The iron-bearing components, by contrast, are reducing, especially under the basic conditions associated with the magnesium compounds, and they do generate hydrogen:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Serpentine is the product of the reaction between water and fayalite's ferrous (Fe&lt;sup&gt;2+&lt;/sup&gt;) ions. The process is of interest because it generates hydrogen gas:[2][3]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$3 \text{Fe}_2\text{SiO}_4 + 2 \text{H}_2\text{O} → 2 \text{Fe}_3\text{O}_4 + 3 \text{SiO}_2 + 2 \text{H}_2$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The reaction can be viewed simplistically as follows:[4][5]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$6 \text{Fe(OH)}_2 → 2 \text{Fe}_3\text{O}_4 + 4 \text{H}_2\text{O} + 2 \text{H}_2$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In addition, in the presence of carbonates and sulfates the reduction process can also produce methane and hydrogen sulfide.  The references cited in this passage explore these processes as sources of raw material and chemically stored energy for undersea life both in Earth and in subterranean ocean worlds elsewhere in the Solar System.&lt;/p&gt;&#xA;&lt;p&gt;Cited references:&lt;/p&gt;&#xA;&lt;p&gt;1.&lt;br /&gt;&#xA;&amp;quot;Serpentinization: The Heat Engine at Lost City and Sponge of the Oceanic Crust&amp;quot;.  &lt;a href=&quot;http://www.lostcity.washington.edu/science/chemistry/serpentinization.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Link&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;2.&#xA;&amp;quot;Methane and hydrogen formation from rocks – Energy sources for life&amp;quot;. Retrieved 6 November 2011.  &lt;a href=&quot;http://www.lostcity.washington.edu/science/chemistry/methane.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Link&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;3.&#xA;Sleep, N.H.; A. Meibom, Th. Fridriksson, R.G. Coleman, D.K. Bird (2004). &amp;quot;H2-rich fluids from serpentinization: Geochemical and biotic implications&amp;quot;. Proceedings of the National Academy of Sciences of the United States of America. 101 (35): 12818–12823. Bibcode:2004PNAS..10112818S. &lt;a href=&quot;https://www.pnas.org/content/101/35/12818&quot; rel=&quot;nofollow noreferrer&quot;&gt;doi:10.1073/pnas.0405289101&lt;/a&gt;. PMC 516479. PMID 15326313.&lt;/p&gt;&#xA;&lt;p&gt;4.&#xA;Russell, M. J.; Hall, A. J.; Martin, W. (2010). &amp;quot;Serpentinization as a source of energy at the origin of life&amp;quot;. Geobiology. 8 (5): 355–371. &lt;a href=&quot;https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1472-4669.2010.00249.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;doi:10.1111/j.1472-4669.2010.00249.x.&lt;/a&gt; PMID 20572872.&lt;/p&gt;&#xA;&lt;p&gt;5.&#xA;Schrenk, M. O.; Brazelton, W. J.; Lang, S. Q. (2013). &amp;quot;Serpentinization, Carbon, and Deep Life&amp;quot;. Reviews in Mineralogy and Geochemistry. 75 (1): 575–606. Bibcode:2013RvMG...75..575S. &lt;a href=&quot;https://pubs.geoscienceworld.org/msa/rimg/article-abstract/75/1/575/140987/Serpentinization-Carbon-and-Deep-Life?redirectedFrom=fulltext&quot; rel=&quot;nofollow noreferrer&quot;&gt;doi:10.2138/rmg.2013.75.18.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2020-08-25T00:17:16.567" LastActivityDate="2020-08-25T00:17:16.567" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20114" PostTypeId="1" CreationDate="2020-08-23T19:54:03.097" Score="5" ViewCount="123" Body="&lt;p&gt;While walking in a state park yesterday in the Chattanooga, TN area we came across a rock that looked like this. Is it some kind of holdfast or washout from cement work? (There is an old reservoir nearby.) The rock layers in the area are Pennsylvanian.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GfnLA.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GfnLA.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MlMcw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MlMcw.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20949" LastEditorUserId="6016" LastEditDate="2020-08-28T12:01:34.030" LastActivityDate="2020-08-28T12:01:34.030" Title="What is this fossil?" Tags="|fossils|" AnswerCount="0" CommentCount="4" ClosedDate="2020-08-24T04:45:00.947" ContentLicense="CC BY-SA 4.0" />
  <row Id="20117" PostTypeId="1" CreationDate="2020-08-23T23:50:18.703" Score="3" ViewCount="189" Body="&lt;p&gt;In my study, I found that in volcanoes when the magma is going up it formed different types of rocks. There are basic, acidic and ultrabasic.&lt;/p&gt;&#xA;&lt;p&gt;My question is why isn't there ultra acid igneous rocks formed?&lt;/p&gt;&#xA;" OwnerUserId="20951" LastEditorUserId="2470" LastEditDate="2020-08-24T00:28:26.530" LastActivityDate="2022-10-31T17:12:02.620" Title="Why aren't there ultra acid igneous rocks?" Tags="|plate-tectonics|volcanology|rocks|igneous|volcanic-eruption|" AnswerCount="2" CommentCount="3" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20118" PostTypeId="1" AcceptedAnswerId="20121" CreationDate="2020-08-24T09:23:53.987" Score="2" ViewCount="613" Body="&lt;p&gt;Can someone please provides me with the recursion relations of Associated Legendre Polynomials when using Schmidt quasi-normalization? I need that in the context of Geomagnetism to obtain the Spherical Harmonics coefficients g and h.&lt;/p&gt;&#xA;" OwnerUserId="20950" LastActivityDate="2020-08-24T22:47:07.703" Title="Recursion relations of Associated Legendre Polynomials with Schmidt Semi-normalization" Tags="|geomagnetism|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20119" PostTypeId="2" ParentId="20058" CreationDate="2020-08-24T12:02:59.817" Score="2" Body="&lt;p&gt;In fact it is possible, the early warning system is not something more than a series of accelerometers (seismometers). There is always an epicenter for an earthquake. closer sensors to the epicenter shorten the time for occurrence announcement and more time for far locations to get ready.&lt;/p&gt;&#xA;&lt;p&gt;There are even some efforts to use personal cellphones accelerometer sensors as a part of broad early warning system. for example &lt;a href=&quot;https://www.theverge.com/2020/8/11/21362370/android-earthquake-detection-seismometer-epicenter-shakealert-google&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;https://www.rms.com/blog/2019/10/21/myshake-new-app-unveiled-for-california-earthquake-early-warning?gclid=CjwKCAjwyo36BRAXEiwA24CwGTbUnIdJJ8ozJtGjzs6IP5JtJjHrI4JhjoS4xtjlsEHQKsplgcx8KRoCRdIQAvD_BwE&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; . &lt;a href=&quot;https://raspberryshake.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;RaspberryShake&lt;/a&gt; home sensors can also contribute in a global effort to shorten seismic events announcements. you can follow some live data shared by this home instruments in &lt;a href=&quot;https://www.iris.edu/hq/jamaseis/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iris jamaseis software,&lt;/a&gt; freely.&#xA;This should be noted that all these efforts are still in early stages. Currently some seismically active cities are equipped with early warning systems but not based on home sensors but on seismic networks.&lt;/p&gt;&#xA;" OwnerUserId="20956" LastActivityDate="2020-08-24T12:02:59.817" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20120" PostTypeId="1" CreationDate="2020-08-24T13:38:46.790" Score="1" ViewCount="69" Body="&lt;p&gt;To calculate the anomaly of a variable (temperature, for example) I need the climatology (at least 30 years) of that variable. Which climatology data source should I use? Should I use the &amp;quot;climatology&amp;quot; of the weather forecasts? In this case, does the fact that the versions of the models have changed, and each model has a bias, interfere with the quality of the result? I have already read that it is not correct to use CFSR data to calculate the anomaly since 2011. I would like someone with experience in the area to explain the  best way to calculate the anomaly for (GFS/GFS) forecasts. And where it is possible to obtain the climatological data for this calculation.&#xA;Thank you very much in advance.&lt;/p&gt;&#xA;" OwnerUserId="20957" LastActivityDate="2020-08-24T13:38:46.790" Title="What is the best way to calculate anomaly of meteorological variables with the (GFS/GEFS) forecast" Tags="|meteorology|weather-forecasting|atmosphere-modelling|gfs|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20121" PostTypeId="2" ParentId="20118" CreationDate="2020-08-24T14:51:06.747" Score="2" Body="&lt;p&gt;FYI, the usual reference relied on for the equations used in geomagnetism is:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Langel, R. A. &amp;quot;Chapter four: Main field.&amp;quot; Geomagnetism, edited by JA Jacobs (1987).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;If it wasn't for lockdown I'd have copied from the book locked in my office to make sure I got it right...but until someone corrects me...&lt;/p&gt;&#xA;&lt;p&gt;The Schmidt quasi/semi-normalisations for the associated Legendre polynomials are given by these recursions, in the form you'd actually use for calculations typically:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://latex.codecogs.com/gif.latex?S_%7B0,0%7D=1&quot; title=&quot;S_{0,0}=1&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://latex.codecogs.com/gif.latex?S_%7Bn,0%7D=S_%7Bn-1,0%7D%5Cleft&amp;space;(&amp;space;%5Cfrac%7B2n-1%7D%7Bn%7D&amp;space;%5Cright&amp;space;)&quot; title=&quot;S_{n,0}=S_{n-1,0}\left ( \frac{2n-1}{n} \right )&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://latex.codecogs.com/gif.latex?S_%7Bn,m%7D=S_%7Bn,m-1%7D&amp;space;%5Csqrt%7B&amp;space;%5Cfrac%7B(n-m&amp;plus;1)(%5Cdelta_m%5E1&amp;plus;1)%7D%7Bn&amp;plus;m%7D&amp;space;%7D&quot; title=&quot;S_{n,m}=S_{n,m-1} \sqrt{ \frac{(n-m+1)(\delta_m^1+1)}{n+m} }&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;Note that if you use Schmidt normalisation of Legendre polynomials from a given software language to do calculations, you &lt;em&gt;do not&lt;/em&gt; want to include the Condon-Shortley phase factor of &lt;img src=&quot;https://latex.codecogs.com/gif.latex?(-1)%5E%7Bm%7D&quot; title=&quot;(-1)^{m}&quot; /&gt;. So check if it is included in the Legendre polynomial and/or normalisation formula.&lt;/p&gt;&#xA;&lt;p&gt;Edit: Some links to open source geomagnetism compatible software for calculating Schmidt normalised associated Legendre polynomials.&lt;/p&gt;&#xA;&lt;p&gt;Python: &lt;a href=&quot;https://github.com/ancklo/ChaosMagPy/blob/72c22e67dc844a71dcb678a1e81bdcde9f0c9627/chaosmagpy/model_utils.py#L665&quot; rel=&quot;nofollow noreferrer&quot;&gt;ChaosMagPy&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Python/Fortran-95: &lt;a href=&quot;https://github.com/SHTOOLS/SHTOOLS/blob/master/pyshtools/legendre/legendre_functions.py&quot; rel=&quot;nofollow noreferrer&quot;&gt;SHTools&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14123" LastEditorUserId="14123" LastEditDate="2020-08-24T22:47:07.703" LastActivityDate="2020-08-24T22:47:07.703" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="20122" PostTypeId="1" AcceptedAnswerId="20123" CreationDate="2020-08-25T01:42:44.533" Score="1" ViewCount="61" Body="&lt;p&gt;My location is India (this is to mention the context). The question I submit here is a common man's query (the level of this question and the expected answer).&lt;/p&gt;&#xA;&lt;p&gt;Water is essential for the growth of plants and trees. Why does then autumn follow the rainy season? When the rainy season brings so much water, which is essential for the growth of plants, why doesn't spring follow the rainy season?&lt;/p&gt;&#xA;" OwnerUserId="20962" LastActivityDate="2020-08-25T07:50:57.937" Title="Why autumn follows the rainy season" Tags="|vegetation|plant|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20123" PostTypeId="2" ParentId="20122" CreationDate="2020-08-25T05:04:49.977" Score="1" Body="&lt;p&gt;The precise reasons for leaf shedding after monsoon aren't well known and studied, but there are vague reasons like optimising use of light and warmth for max photosynthetic gain. So the tree has a heavy load of leaves to grow fast in monsoon, and it fast depletes the groundwater if it keeps the leaves in the dry season. read the conclusion here: &lt;a href=&quot;https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1466-8238.2006.00213.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1466-8238.2006.00213.x&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Trees need to store reserves to allow their survival during winter and for bud flush and leaf growth in the following spring.&lt;/p&gt;&#xA;&lt;p&gt;Generally it takes 2 weeks or a month for a deciduous tree to prepare dormancy/sleep time, to gather all the nitrogen, glucose and nutritive elements from their leaves.&#xA;If the plant keeps on growing when it's leaves are adapted to massive rainfall, it may lose the green leaves rather than gather useful elements and prepare for dormancy.&lt;/p&gt;&#xA;&lt;p&gt;i.e. from this image you can see the winter stored sugar being used to grow new leaves, for this tree the spring is in april: &lt;a href=&quot;https://i.stack.imgur.com/jfqDL.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jfqDL.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;There's some interesting facts about leaves here: &lt;a href=&quot;https://en.wikipedia.org/wiki/Autumn_leaf_color#Function_of_autumn_colors&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Autumn_leaf_color#Function_of_autumn_colors&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2020-08-25T07:50:57.937" LastActivityDate="2020-08-25T07:50:57.937" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20125" PostTypeId="2" ParentId="20117" CreationDate="2020-08-25T09:09:20.263" Score="5" Body="&lt;p&gt;Warning: not an igneous petrologist here, I'm more interested in what happens to magmas once they reach the surface than all the processes they might have encountered along the way...&lt;/p&gt;&#xA;&lt;p&gt;That being said, I think it has to do with the source of magmas, that is the mantle, which is itself mafic. Hence partial melting of the mantle generates mafic magmas. These magmas can then &lt;a href=&quot;https://en.wikipedia.org/wiki/Igneous_differentiation&quot; rel=&quot;nofollow noreferrer&quot;&gt;differentiate&lt;/a&gt; into more &amp;quot;evolved&amp;quot; (i.e., intermediate or felsic) ones. But there are limitations to these differentiation processes. With fractional crystallization you make mafic minerals, pumping Mg and Fe from the melt and leaving it silica-enriched, but you will never reach a 100 % silica melt (after all mafic minerals are still silicates, they need some Si in their structure). Same with crustal assimilation: the continental crust is only andesitic (intermediate) on average (&lt;a href=&quot;https://doi.org/10.1038/378571a0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rudnick 1995&lt;/a&gt;), and even with assimilation of more felsic (i.e., granitic) portions you would never reach a 100 % silica melt. The starting material is too mafic.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;On a more &amp;quot;philosophical&amp;quot; note, I would add that despite the absence of the term &amp;quot;ultrafelsic&amp;quot; in the literature, one could still consider some rocks as being ultrafelsic. If you look at the chemical classification of volcanic rocks (&lt;a href=&quot;https://doi.org/10.1017/CBO9780511535581&quot; rel=&quot;nofollow noreferrer&quot;&gt;Le Maître et al. 2002&lt;/a&gt;), the four fields are separated like this (silica content in wt%):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Ultramafic: SiO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; &amp;lt; 45&lt;/li&gt;&#xA;&lt;li&gt;Mafic: 45 &amp;lt; SiO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; &amp;lt; 52&lt;/li&gt;&#xA;&lt;li&gt;Intermediate: 52 &amp;lt; SiO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; &amp;lt; 63&lt;/li&gt;&#xA;&lt;li&gt;Felsic: SiO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; &amp;gt; 63&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;So everything above 63 wt% SiO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; is just &amp;quot;felsic&amp;quot;. But there are some rhyolites with more than 76 wt% SiO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; (some of the Mono Domes for instance, see Table 2 in &lt;a href=&quot;https://doi.org/10.1007/s00445-017-1123-y&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bray et al. 2017&lt;/a&gt;)! So there is no distinction between a low-silica dacite and a high-silica rhyolite: they all are just &amp;quot;felsic&amp;quot;. That doesn't mean they are not different, just that we never bothered making a fifth field. But those fields are just arbitrary, we could have split the silica spectrum into twelve fields, or just two.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2022-10-31T09:44:58.907" LastActivityDate="2022-10-31T09:44:58.907" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20131" PostTypeId="1" CreationDate="2020-08-28T11:25:57.660" Score="3" ViewCount="117" Body="&lt;p&gt;Can a cloud ever be &lt;strong&gt;stationary&lt;/strong&gt; with respect to the ground surface? For some reason (experience, logic?) it seems to me such case is not possible. I read that &lt;a href=&quot;https://en.wikipedia.org/wiki/Stationary_front&quot; rel=&quot;nofollow noreferrer&quot;&gt;stationary fronts&lt;/a&gt; are defined as two air masses such that&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;neither air mass is strong enough to advance into the other at least 5 knots (about 6 miles per hour or about 9 kilometers per hour) at the ground surface&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;But this is not referring directly to clouds' speed, nor discussing the particular case of speed equal to 0.&lt;/p&gt;&#xA;&lt;p&gt;There are the &lt;a href=&quot;https://en.wikipedia.org/wiki/Lenticular_cloud&quot; rel=&quot;nofollow noreferrer&quot;&gt;lenticular clouds&lt;/a&gt;, which are defined as stationary, but it is not clear to me whether such stationarity is strict (0 knots per hour) or rather a very low speed relative to &amp;quot;normal&amp;quot; clouds.&lt;/p&gt;&#xA;&lt;p&gt;Anyone can provide insights on this?&lt;/p&gt;&#xA;" OwnerUserId="13541" LastActivityDate="2020-08-28T11:25:57.660" Title="Do clouds always move?" Tags="|clouds|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20132" PostTypeId="1" AcceptedAnswerId="20133" CreationDate="2020-08-28T18:31:22.690" Score="10" ViewCount="2643" Body="&lt;p&gt;&lt;a href=&quot;https://ozonewatch.gsfc.nasa.gov/facts/dobson_SH.html&quot; rel=&quot;noreferrer&quot;&gt;It is said&lt;/a&gt; about ozone:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;a layer in the earth's stratosphere at an altitude of about 10 km (6.2 miles) containing a high concentration of ozone&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Over the Earth’s surface, the ozone layer’s &lt;em&gt;average&lt;/em&gt; thickness is about 300 Dobson Units or a layer that is 3 millimetres thick. (nasa)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So, how does the Ozone gas stays in that altitude without dissolving?&lt;/p&gt;&#xA;" OwnerUserId="20986" LastEditorUserId="6016" LastEditDate="2020-08-29T12:18:07.610" LastActivityDate="2020-08-29T19:54:04.263" Title="How does the ozone layer &quot;stay in place&quot;?" Tags="|ozone|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20133" PostTypeId="2" ParentId="20132" CreationDate="2020-08-28T20:04:37.763" Score="16" Body="&lt;p&gt;For the ozone layer to dissolve, it would need something to bind to. &lt;a href=&quot;https://en.wikipedia.org/wiki/Chlorofluorocarbon&quot; rel=&quot;noreferrer&quot;&gt;Chloroflurocarbons&lt;/a&gt; are one very notable thing that it can bind to, but that doesn't exactly answer the question.&lt;/p&gt;&#xA;&lt;p&gt;While the ozone layer would be 3 mm thick if it was compressed down to the pressure of earth's surface, since it is further up in the atmosphere, it can take up a larger volume (like 20 km thick). The ozone layer is maintained by the &lt;a href=&quot;http://glossary.ametsoc.org/wiki/Chapman_mechanism&quot; rel=&quot;noreferrer&quot;&gt;Chapman cycle&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;That is, the oxygen molecule (&lt;span class=&quot;math-container&quot;&gt;$\ce{O_2}$&lt;/span&gt;) is dissociated by UV radiation (photolysis) to oxygen atoms (&lt;span class=&quot;math-container&quot;&gt;$\ce{2O}$&lt;/span&gt;). Then the photolyzed oxygen atoms (&lt;span class=&quot;math-container&quot;&gt;$\ce{2O}$&lt;/span&gt;) can bond with two oxygen molecules (&lt;span class=&quot;math-container&quot;&gt;$\ce{2O_2}$&lt;/span&gt;) to make an two ozone molecules (&lt;span class=&quot;math-container&quot;&gt;$\ce{2O_3}$&lt;/span&gt;), provided another molecule can take away some excess energy.&lt;/p&gt;&#xA;&lt;p&gt;Since it is a cycle, there has to be a way for the ozone to return to oxygen. One ozone molecule (&lt;span class=&quot;math-container&quot;&gt;$\ce{O_3}$&lt;/span&gt;) can photolyze to make an oxygen atom (&lt;span class=&quot;math-container&quot;&gt;$\ce{O}$&lt;/span&gt;) and oxygen molecule (&lt;span class=&quot;math-container&quot;&gt;$\ce{O_2}$&lt;/span&gt;). The oxygen atom (&lt;span class=&quot;math-container&quot;&gt;$\ce{O}$&lt;/span&gt;) can react with another ozone molecule (&lt;span class=&quot;math-container&quot;&gt;$\ce{O_3}$&lt;/span&gt;) to make two oxygen molecules (&lt;span class=&quot;math-container&quot;&gt;$\ce{2O_2}$&lt;/span&gt;).&lt;/p&gt;&#xA;&lt;p&gt;To just answer your question directly, the ozone layer is replenished by the sun's UV energy reacting with the oxygen in the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-08-28T20:04:37.763" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20134" PostTypeId="1" CreationDate="2020-08-29T11:41:47.007" Score="4" ViewCount="73" Body="&lt;p&gt;The ozone layer has been weakened by humans over the last century, but is slowly recovering.  Can humanity help undo the damage faster by manufacturing and releasing ozone?&lt;/p&gt;&#xA;&lt;p&gt;Would it be enough to simply vent ozone at point of manufacture, or would it be better released at the 10 km height?&lt;/p&gt;&#xA;&lt;p&gt;Would the latitude of release have an effect?   IE, would ozone release be faster/more effective at the poles?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Inspired by &lt;a href=&quot;https://earthscience.stackexchange.com/questions/20132/how-does-the-ozone-layer-stay-in-place&quot;&gt;how does the ozone layer &amp;quot;stay in place&amp;quot;?&lt;/a&gt; which says (paraphrased) &amp;quot;the ozone layer is 10km thick at height which would be 3mm thick at sea level&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;and by &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4529/has-a-reduction-in-car-use-ever-had-an-effect-on-the-ozone-layer&quot;&gt;Has a reduction in car use ever had an effect on the ozone layer?&lt;/a&gt; which suggests total recovery is at least 30 years away for mid latitudes and longer for the antarctic hole.&lt;/p&gt;&#xA;" OwnerUserId="19210" LastActivityDate="2020-08-29T16:52:34.357" Title="Can humanity help reinforce the ozone layer?" Tags="|human-influence|ozone|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20135" PostTypeId="2" ParentId="20134" CreationDate="2020-08-29T16:52:34.357" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Would it be enough to simply vent ozone at point of manufacture, or would it be better released at the 10 km height?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Neither. The right answer is not to do it at all. Surface level ozone is deemed to be a pollutant. It is highly irritating to people. Ten kilometers is still in the troposphere. Ozone in the troposphere rarely makes its way to the stratosphere. Ozone is highly reactive, and there is plenty of stuff in the troposphere that ozone can readily oxidize. If this was to be done (which is a bad idea), the ozone would have to be released into the stratosphere. Ozone concentration peaks at about twenty kilometers altitude.&lt;/p&gt;&#xA;&lt;p&gt;Why not at all? There are three billion metric tons of ozone in the stratosphere. Think of how much effort augmenting that would take, and how much ozone depleting chemicals would be deposited into the stratosphere while doing so. Jet engine and rocket exhaust contain chemicals that deplete ozone.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-08-29T16:52:34.357" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20136" PostTypeId="1" AcceptedAnswerId="20139" CreationDate="2020-08-29T18:13:59.193" Score="3" ViewCount="145" Body="&lt;p&gt;Hi everybody who sees this post, I need urgent help for finding all official world wide standards of the manganese mining.&lt;/p&gt;&#xA;&lt;p&gt;Problem is that, many houses has been damaged in my village with manganese mining, mainly because of underground explosions. Company which runs this type of operations, does not make any information about standards public.&lt;/p&gt;&#xA;&lt;p&gt;so my questions are:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;where can I found OFFICIAL document which describes calculation formula about how far should the house be to consider it officially damaged, and can ask for compensation from the company.&lt;/li&gt;&#xA;&lt;li&gt;Is it possible for company to have it's own standard when it comes to damaging properties, I mean their custom formulas or something like that.&lt;/li&gt;&#xA;&lt;li&gt;Is their any websites which lists the countries which should follow worldwide standards of mining ?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="20989" LastEditorUserId="543" LastEditDate="2024-01-08T01:44:11.457" LastActivityDate="2024-01-08T01:44:11.457" Title="Where can I find worldwide standards of manganese mining?" Tags="|geology|atmosphere|air-pollution|mining|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20137" PostTypeId="2" ParentId="20132" CreationDate="2020-08-29T19:54:04.263" Score="4" Body="&lt;p&gt;Above accepted answer provide very good explanation to the question. I did some research on it and found some reasons &lt;em&gt;why&lt;/em&gt; Ozone layer stays there instead somewhere else.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;TL;DR :&lt;/strong&gt; Higher the altitude, higher the solar radiation energy. That makes &lt;span class=&quot;math-container&quot;&gt;${O_2}$&lt;/span&gt; more excited and easier to break &lt;span class=&quot;math-container&quot;&gt;${O-O}$&lt;/span&gt; bond. Also the concentration of oxygen need to be sufficient, but higher the altitude lower the oxygen as atmosphere become less dense. The equilibrium is where the Ozone layer is.&lt;/p&gt;&#xA;&lt;p&gt;Following image from &lt;a href=&quot;https://ozonewatch.gsfc.nasa.gov/facts/NH.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA Ozone Watch&lt;/a&gt; shows the &lt;span class=&quot;math-container&quot;&gt;$\ce{O_3}$&lt;/span&gt; concentration with altitude&#xA;&lt;a href=&quot;https://i.stack.imgur.com/LeHba.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LeHba.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Center for Coastal Physical Oceanography's &lt;a href=&quot;http://www.ccpo.odu.edu/SEES/ozone/class/Chap_5/5_2.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;website&lt;/a&gt; has some nice explanation why 40km altitude has highest &lt;span class=&quot;math-container&quot;&gt;$\ce{O_3}$&lt;/span&gt; concentration.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Ozone photochemistry is driven by the interaction of the Sun's&#xA;radiation with various gases in the atmosphere, particularly oxygen.&#xA;The understanding of the basics of ozone photochemistry began with&#xA;Chapman (1930), who hypothesized that UV radiation was responsible for&#xA;ozone production and proceeded to lay the foundation of stratospheric&#xA;photochemistry: the Chapman reactions. He proposed that atomic oxygen&#xA;is formed by the splitting (dissociation) of &lt;span class=&quot;math-container&quot;&gt;$\ce{O_2}$&lt;/span&gt; by high energy&#xA;ultraviolet photons (i.e., packets of light energy with wavelengths&#xA;shorter than 242 nanometers) via&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{O_2 + hc/\lambda -&amp;gt; O + O}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where h is the Planck constant, c is the&#xA;speed of light, and &lt;span class=&quot;math-container&quot;&gt;${\lambda}$&lt;/span&gt; is the wavelength of the photon, given in&#xA;nanometers (abbreviated nm, where 1 nm=10-9 meter). Collectively,&#xA;&lt;span class=&quot;math-container&quot;&gt;$\ce{hc/\lambda}$&lt;/span&gt; represents the photon of light that breaks up the &lt;span class=&quot;math-container&quot;&gt;$\ce{O_2}$&lt;/span&gt;&#xA;molecule. The top panel of Figure 5.01 displays the absorption cross&#xA;section for oxygen multiplied by 10,000. The cross-section is&#xA;proportional to the probability that a photon from the Sun will be&#xA;absorbed by an oxygen molecule. While this probability increases for&#xA;the shorter, more energetic photons, the amount of UV radiation with&#xA;wavelength shorter than 242nm reaching into the atmosphere falls&#xA;dramatically with decreasing altitude.&lt;/p&gt;&#xA;&lt;p&gt;The bottom of Figure 5.01 shows the amount of solar energy per unit&#xA;area (the flux) of different wavelengths reaching to three different&#xA;altitudes: the top of the atmosphere, 30 km, and the surface. The&#xA;amount of very energetic UV (&amp;lt; 242 nm) radiation falls off sharply.&#xA;Thus, the splitting apart or photolysis of oxygen molecules by solar&#xA;radiation is relatively slow in the lower and middle stratosphere&#xA;because the photons of sufficient energy have already been absorbed by&#xA;molecular oxygen in the upper stratosphere in the Chapman reaction&#xA;given above. Few such photons are able to penetrate deeply into the&#xA;atmosphere&lt;/p&gt;&#xA;&lt;p&gt;Figure 5.01 is below&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zEPhY.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zEPhY.jpg&quot; alt=&quot;Figure 5.01&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="20986" LastActivityDate="2020-08-29T19:54:04.263" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20138" PostTypeId="2" ParentId="16577" CreationDate="2020-08-29T20:29:49.437" Score="3" Body="&lt;p&gt;I've found two sources for molecular hydrogen.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The photolysis of formaldehyde (See &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/JD095iD10p16343&quot; rel=&quot;nofollow noreferrer&quot;&gt;chemical formula 10&lt;/a&gt; and see &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/1999JD900788&quot; rel=&quot;nofollow noreferrer&quot;&gt;Novelli et al. 1999&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.nature.com/articles/347743a0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Anthropogenic sources.&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;While it isn't a source I think I should mention the &lt;a href=&quot;https://en.wikipedia.org/wiki/Exosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;exosphere&lt;/a&gt;. The exosphere is not very dense, so hydrogen (probably) doesn't react with anything. Since it is the lightest element, it probably doesn't go anywhere except out of the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-08-29T20:29:49.437" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20139" PostTypeId="2" ParentId="20136" CreationDate="2020-08-30T00:06:23.123" Score="8" Body="&lt;p&gt;Your issue is an issue for all types of mining near residential or built up areas, not just manganese mining.&lt;/p&gt;&#xA;&lt;p&gt;The distance that mines should be from built up areas depends on&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the competency of the ground&lt;/li&gt;&#xA;&lt;li&gt;whether the ground is hard or soft&lt;/li&gt;&#xA;&lt;li&gt;the type of explosive used - more particularly the energy released by&#xA;the explosives used. This influences the blast vibrations produced.&#xA;Currently Australian and New Zealand recommendation is a &lt;a href=&quot;https://ballaratgoldmine.com.au/blasting-fact-sheet/&quot; rel=&quot;nofollow noreferrer&quot;&gt;maximum&#xA;blast vibration of 10 mm/s&lt;/a&gt; in residential areas, preferably less than 2.5 m/s.&lt;/li&gt;&#xA;&lt;li&gt;the amount of explosives detonated at a time. Many smaller blasts are&#xA;usually better than one very large blast.&lt;/li&gt;&#xA;&lt;li&gt;the presence of geological structures that may preferentially carry&#xA;and appear to amplify blast energy&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The trouble with laws and standards for such things is they vary between mining jurisdictions. Even within countries, such as the US, Canada and Australia they can vary between states or provinces. Such countries do not have national legislation for the operation of mines. Each state of province is responsible for such laws within its jurisdiction.&lt;/p&gt;&#xA;&lt;p&gt;In the 1980s, in the State of New South Wales in Australia, to protect lakes and dams from unexpected drainage and also to protect underground coal mines and the people that work in them from water inundation from lakes, dams or other such large stores of surface water a 45 degree angle rule was used.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;From the edge of the lake draw a 45 degree line downwards. Where that line intersects the horizontal, or near horizontal, coal seam that defines the closest proximity the mine was allowed to get near the surface lake or dam.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Because of the geometry of a 45 degree triangle both of the shorter sides are the same length. In the case of this rule the distance from the edge of the lake or dam is equal to the depth of mining.&lt;/p&gt;&#xA;&lt;p&gt;One of the problems with this rule is coal mines in Australia do not use explosives. Coal is mined using cutting machines via &lt;a href=&quot;https://en.wikipedia.org/wiki/Longwall_mining&quot; rel=&quot;nofollow noreferrer&quot;&gt;longwall mining&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;In the City of Ballarat, Australia, gold mining resumed in the 1990s, after the closure of mines during the 1914 to 1918 world war because of a labor shortage. The &lt;a href=&quot;https://ballaratgoldmine.com.au/mining-activities/&quot; rel=&quot;nofollow noreferrer&quot;&gt;mine operates underneath the city&lt;/a&gt; of 105 000 people.&lt;/p&gt;&#xA;&lt;p&gt;Under the license to operate, from the State Government of Victoria:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Our licence conditions state that the vibration limit for blasting is 10 mm/sec and that 95% of all blasts must be below 5 mm/sec.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The mine has a &lt;strong&gt;self imposed&lt;/strong&gt; limit of 2.5 mm/s.&lt;/p&gt;&#xA;&lt;p&gt;Existing underground mine development, in blue, as of July 2020.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GKi6U.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GKi6U.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Under a &lt;a href=&quot;https://ballaratgoldmine.com.au/exploration/&quot; rel=&quot;nofollow noreferrer&quot;&gt;proposed expansion to the mine&lt;/a&gt;, the newer region will be approximately 50 m below the surface. See the sectional diagram at the end of the webpage. The surface is at elevation RL 1205 and the top of the Nick O' Time Shoot is elevation RL 1150. I suspect this region will under fields or forest.&lt;/p&gt;&#xA;&lt;p&gt;Generally, for mines under urban environments 100 m is the closest that mines come to the foundations of buildings. This is not primarily due to blasting waves and seismic activity from blasting, but the requirement to maintain a thickness of competent rock beneath buildings to minimize potential for future subsidence.&lt;/p&gt;&#xA;&lt;p&gt;Factors that are considered in this thickness are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The strength and competency of the ground below the buildings&lt;/li&gt;&#xA;&lt;li&gt;The largest size of opening that will be developed underground&lt;/li&gt;&#xA;&lt;li&gt;Whether the stopes, the chambers from where ore is mined, are&#xA;backfilled once the ore has been mined.&lt;/li&gt;&#xA;&lt;li&gt;If the stopes are backfilled, with what will they be backfilled:&#xA;loose waste rock, cemented waste rock, loose sand, cemented sand or&#xA;paste fill (larger grained tailings from the processing plant that is&#xA;mixed with cement so it resembles toothpaste and is pumped into the&#xA;mined stopes).&lt;/li&gt;&#xA;&lt;li&gt;The degree to which the stopes will be backfilled. Except for the&#xA;placement of paste fill, stopes cannot be fully backfilled because of&#xA;operational restrictions when other methods are used. There is usually&#xA;an air gap of between 2 and 5 m in the top portion of the stope that&#xA;cannot be filled.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Backfill prevents the wall of the stopes from collapsing and it minimizes the amount of subsidence that can occur above the stopes.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0wDEw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0wDEw.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;In your situation, something else to be wary of is exposure to manganese dust from the mine or processing plant. The human body requires small amounts of &lt;a href=&quot;https://www.lenntech.com/periodic/elements/mn.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;manganese&lt;/a&gt;, but too much can be toxic. Excessive exposure can lead to heath problems with the respiratory tract and/or the brain.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Manganese effects occur mainly in the respiratory tract and in the brains. Symptoms of manganese poisoning are hallucinations, forgetfulness and nerve damage. Manganese can also cause Parkinson, lung embolism and bronchitis. When men are exposed to manganese for a longer period of time they may become impotent.&#xA;A syndrome that is caused by manganese has symptoms such as schizophrenia, dullness, weak muscles, headaches and insomnia.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Additional references concerning exposure to excessive amounts of manganese:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://ods.od.nih.gov/factsheets/manganese-healthprofessional/&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Institutes of Health&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166881/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Impact of open manganese mines on the health of children dwelling&#xA;in the surrounding area&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.cdc.gov/niosh/topics/manganese/default.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Centers for Disease Control and Prevention (USA)&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.euro.who.int/__data/assets/pdf_file/0003/123078/AQG2ndEd_6_8Manganese.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;World Health Organization&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit 5 September 2020&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;There is no formula, simple or complex, that will let you calculate how close an active underground mining region can be to buildings on the surface. The reasons for this are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Geology is complex: different rock types, strength of rock masses&#xA;laterally and at depth, geological structures such as&#xA;discontinuities, faults and folds.&lt;/li&gt;&#xA;&lt;li&gt;How the ground propagates blast energy.&lt;/li&gt;&#xA;&lt;li&gt;The magnitude of the blast energy produced during mining.&lt;/li&gt;&#xA;&lt;li&gt;Quality of construction of surface buildings: flexibility and&#xA;rigidity.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Unlike steel, rock is not uniform in its properties everywhere. Various types of steel are made according to a recipe: some much iron, so much carbon, so much nickel or chromium. Steel is also given different types of treatments when produced, such as hot or cold quenching, forging. All this affects the strength and other properties of various types of steel.&lt;/p&gt;&#xA;&lt;p&gt;When constantly made to the same recipe each type of steel can be tested to determine its properties. With this knowledge, structural and civil engineering can design a building, or any other structure, anywhere in the world with confidence knowing the steel will always behave the same way. Likewise for mechanical engineers when they design parts for machines.&lt;/p&gt;&#xA;&lt;p&gt;This cannot be said of geological material, such as rock. &lt;a href=&quot;https://en.wikipedia.org/wiki/Limestone&quot; rel=&quot;nofollow noreferrer&quot;&gt;Limestone&lt;/a&gt; behaves differently to &lt;a href=&quot;https://en.wikipedia.org/wiki/Sandstone&quot; rel=&quot;nofollow noreferrer&quot;&gt;sandstone&lt;/a&gt;, which behaves differently to &lt;a href=&quot;https://en.wikipedia.org/wiki/Basalt&quot; rel=&quot;nofollow noreferrer&quot;&gt;basalt&lt;/a&gt;, which behaves differently to &lt;a href=&quot;https://en.wikipedia.org/wiki/Komatiite&quot; rel=&quot;nofollow noreferrer&quot;&gt;komatiite&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Granite&quot; rel=&quot;nofollow noreferrer&quot;&gt;granite&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Even the same type of rock can behave different in different locations. &lt;a href=&quot;https://en.wikipedia.org/wiki/Discontinuity_(geotechnical_engineering)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Discontinuities&lt;/a&gt; within rock, oxidation, &lt;a href=&quot;https://en.wikipedia.org/wiki/Weathering&quot; rel=&quot;nofollow noreferrer&quot;&gt;weathering&lt;/a&gt;, the effect of water over prolonged periods of time, the effect of ground stresses can all change how a type of rock will behave in different locations.&lt;/p&gt;&#xA;&lt;p&gt;Unlike structural and mechanical engineers, mining engineers cannot have the same level of confidence in the properties of the materials (different rock types) they use. With experience they know that a certain type of rock will behave in certain way, but that may not be totally applicable elsewhere.&lt;/p&gt;&#xA;&lt;p&gt;Because of this, it is not possible to create a formula that can be used everywhere that will state how far an active underground mining region must be from surface buildings.&lt;/p&gt;&#xA;&lt;p&gt;The other factor which would need to considered is the manner of construction of the buildings near the mine. Buildings that are rigid, made of rock or brick will generally experience more damage, if only just cracked walls, than flexible building made of timber or bamboo.&lt;/p&gt;&#xA;&lt;p&gt;Flexible buildings can move to certain degree, through swaying,  when subjected to forces such as blasting energy, seismic shocks from natural earthquakes and very strong winds. This movement can absorb some of the disruptive energy and the building remains intact.&lt;/p&gt;&#xA;&lt;p&gt;Rigid buildings have less opportunity to move when subjected to disruptive forces so they have to absorb more of the disruptive energies and in doing so they are more likely to crack and collapse. This is why buildings in earthquake prone regions (such as Italy), or cyclone/hurricane prone regions (such as northern Australia) are now built according to an &lt;a href=&quot;https://www.fema.gov/emergency-managers/risk-management/building-science/building-codes/earthquakes&quot; rel=&quot;nofollow noreferrer&quot;&gt;earthquake&lt;/a&gt; or cyclone/&lt;a href=&quot;https://en.wikipedia.org/wiki/Hurricane-proof_building&quot; rel=&quot;nofollow noreferrer&quot;&gt;hurricane&lt;/a&gt; code where reinforcing steel is utilized to increase flexibility of the building, when completed.&lt;/p&gt;&#xA;&lt;p&gt;From personnel experience I have seen newer, rigidly made, houses such as the one pictured below,&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vihyK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vihyK.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;experience clacked walls and other damage from underground mine blasting where the house was 2.5 km laterally from a mine and the blast was 500 m below the surface. The active mining zone was 1.5 km laterally from the house.&lt;/p&gt;&#xA;&lt;p&gt;An older, more flexible house, shown below, was only 1 km from the mine and it experienced no damage.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/i0Len.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/i0Len.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;Edit 8 January 2024&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Additional information is available in my answer to the question, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/25451/how-far-should-a-manganese-processing-plant-be-built-from-a-city&quot;&gt;&lt;em&gt;&lt;strong&gt;How far should a Manganese processing plant be built from a city?&lt;/strong&gt;&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2024-01-07T23:36:23.487" LastActivityDate="2024-01-07T23:36:23.487" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20140" PostTypeId="1" AcceptedAnswerId="20143" CreationDate="2020-08-30T15:39:09.910" Score="15" ViewCount="5063" Body="&lt;p&gt;Hurricanes seem to run out of steam when they make landfall.&lt;/p&gt;&#xA;&lt;p&gt;If our planet were entirely covered by ocean, would hurricanes continue indefinitely?  Would they keep gathering energy and increasing in intensity until...?&lt;/p&gt;&#xA;" OwnerUserId="20991" LastActivityDate="2020-09-01T07:28:12.737" Title="Would hurricanes on an ocean planet continue indefinitely?" Tags="|oceanography|tropical-cyclone|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20141" PostTypeId="2" ParentId="20140" CreationDate="2020-08-30T16:24:44.180" Score="15" Body="&lt;p&gt;What is possible in a low-friction world is illustrated by &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Great_Red_Spot#:%7E:text=The%20Great%20Red%20Spot%20is,been%20continuously%20observed%20since%201878.&quot; rel=&quot;noreferrer&quot;&gt;the Great Red Spot on Jupiter&lt;/a&gt;, an anticyclonic storm that has has been continuously observed that fluid planet's surface at least since 1878 (142 years).  Though it has shrunk a bit from its biggest size, it's still big enough to cover the Earth.  The Great Red Spot may have had a longer history, possibly going back another two centuries:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Great Red Spot may have existed since before 1665, but the present spot was first seen only after 1830, and well-studied only after a prominent apparition in 1879. The storm that was seen in the 17th century may have been different than the storm that exists today.[1]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Our own planet is too small for that, but a storm covering a similar fraction of Earth's surface would be as large as the contiguous 48 United States.&lt;/p&gt;&#xA;&lt;p&gt;Cited reference:&lt;/p&gt;&#xA;&lt;p&gt;1.&#xA;Karl Hille (2015-08-04). &amp;quot;Jupiter's Great Red Spot: A Swirling Mystery&amp;quot;. NASA. Retrieved 2017-11-18. &lt;a href=&quot;https://www.nasa.gov/feature/goddard/jupiter-s-great-red-spot-a-swirling-mystery&quot; rel=&quot;noreferrer&quot;&gt;Link&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2020-08-30T16:37:23.190" LastActivityDate="2020-08-30T16:37:23.190" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20142" PostTypeId="1" CreationDate="2020-08-30T17:05:50.440" Score="1" ViewCount="51" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6ZGFr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6ZGFr.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;I was taking photos of a storm moving through the area, Southwest of Fort Worth, Texas and caught this image in one of the series. The photography is a hobby. I was using my IPhone 6. I researched meteorological optical phenomena, rings, circles, halos, compared pictures I found and did not find anything similar. 6:45 in the evening. The angle of the phone was probably 60-70*;SSE sky with sun beginning to set in the West and the moon is visible low in the photo. Thanks.&lt;/p&gt;&#xA;" OwnerUserId="20992" LastEditorUserId="20992" LastEditDate="2020-08-30T17:45:08.003" LastActivityDate="2020-08-30T17:45:08.003" Title="Unusual small bright ring in storm cloud" Tags="|atmospheric-optics|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20143" PostTypeId="2" ParentId="20140" CreationDate="2020-08-30T20:01:22.690" Score="21" Body="&lt;p&gt;No. As it is, many hurricanes never make landfall. In an oceanic world I could see three fates happening:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Hurricanes that dissipate due to dynamical features or climatological features.&lt;/p&gt;&#xA;&lt;p&gt;By dynamical features, I mean things like two hurricanes that shear each other out or produce an environment that can't be sustained. An example of the latter is &lt;a href=&quot;https://www.alabamawx.com/?p=174525&quot; rel=&quot;noreferrer&quot;&gt;upwelling&lt;/a&gt;, which generates cooler water that saps the energy from the hurricane. A climatological feature that might prevent a hurricane from developing indefinitely might be the Azores high. As it is, there are places that hurricanes don't seem to go.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hWF8P.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hWF8P.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Hurricanes that undergo extratropical transition.&lt;/p&gt;&#xA;&lt;p&gt;Notice in the figure above, the hurricanes just disappear near the poles? As they come closer to the poles, the temperature difference becomes larger. Eventually they no longer look like tropical cyclones/hurricanes (little to no temperature difference), but rather look like an extratropical cyclone (see &lt;a href=&quot;https://www.alabamawx.com/?p=195936&quot; rel=&quot;noreferrer&quot;&gt;this link&lt;/a&gt; for some differences). This process is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Extratropical_cyclone#Extratropical_transition&quot; rel=&quot;noreferrer&quot;&gt;Extratropical transition&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://journals.ametsoc.org/jas/article/76/8/2257/343816/Dynamical-Aquaplanet-Experiments-with-Uniform&quot; rel=&quot;noreferrer&quot;&gt;Chavas and Reed (2019)&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;While looking up papers for this question, I stumbled upon this paper. It implies that we would get longer lived hurricanes spreading the entire planet. I'd be a little skeptical of this result though, since it ignores the fact that the earth is heated unevenly, which drives most of the climate.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;On a side note, such simulations do exist. These are called Aquaplanet simulations. Some studies I found include:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1002/jame.20020&quot; rel=&quot;noreferrer&quot;&gt;Li et al. (2011)&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://link.springer.com/article/10.1007/s40641-019-00133-y&quot; rel=&quot;noreferrer&quot;&gt;Merlis and Held (2019)&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://journals.ametsoc.org/jas/article/76/8/2257/343816/Dynamical-Aquaplanet-Experiments-with-Uniform&quot; rel=&quot;noreferrer&quot;&gt;Chavas and Reed (2019)&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016MS000785&quot; rel=&quot;noreferrer&quot;&gt;Viale and Merlis (2017)&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;And for kicks and giggles, if you want to consider what the worst-case scenario for a hurricane could be, such a thing has been named a &amp;quot;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/epdf/10.1029/95JD01368&quot; rel=&quot;noreferrer&quot;&gt;Hypercane&lt;/a&gt;&amp;quot; (see &lt;a href=&quot;https://en.wikipedia.org/wiki/Hypercane#:%7E:text=A%20hypercane%20is%20a%20hypothetical,warmest%20ocean%20temperature%20ever%20recorded.&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;, too).&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="-1" LastEditDate="2020-09-01T07:28:12.737" LastActivityDate="2020-09-01T07:28:12.737" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20145" PostTypeId="1" CreationDate="2020-08-30T20:47:55.973" Score="3" ViewCount="364" Body="&lt;p&gt;I am a little bit confused on the two concepts in structural geology, i.e., what is the relationship of anticline and four-way closure. My understanding is that anticline belongs to four-way closure. Is that right? I did not find any materials that discusses the relationship of these two concept. In the context of seismic image, are there distinguished features that can single out four-way closure?&lt;/p&gt;&#xA;" OwnerUserId="20994" LastActivityDate="2022-09-27T04:22:51.837" Title="regarding four-way closure in structural geology" Tags="|geology|petrology|structural-geology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20146" PostTypeId="1" AcceptedAnswerId="20148" CreationDate="2020-08-28T19:28:15.767" Score="1" ViewCount="111" Body="&lt;p&gt;Obviously, we can look at where continental plates are currently moving, and extrapolate both forwards and backwards in time...&lt;/p&gt;&#xA;&lt;p&gt;But there have (allegedly) been more than supercontinent in the past... What lines of evidence could give such precise maps of pre-Pangeae supercontinent as I have seen in various places?&lt;/p&gt;&#xA;" OwnerUserId="20985" OwnerDisplayName="Kurt Hikes" LastActivityDate="2020-08-31T22:55:20.207" Title="How do scientists know the precise location, etc. of the earliest supercontinents? Or their configurations far, far into the future?" Tags="|geophysics|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20147" PostTypeId="2" ParentId="20146" CreationDate="2020-08-30T21:17:15.973" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;How do scientists know the precise location, etc. of the earliest supercontinents? Or their configurations far, far into the future?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;They don't know, particularly with respect to precise location.&lt;/p&gt;&#xA;&lt;p&gt;There are clues in the rock that give some indication regarding latitude. There are clues in the rock, the shapes of the continents, and extant species and fossils that indicate that regions currently separated by ocean were once very close to one another. There is almost no doubt that Pangea existed between 335 million years ago and 175 million years ago. The precise shape that Pangea took is a bit less understood. Evidence for previous supercontinents fades with time, and is even more suspect.&lt;/p&gt;&#xA;&lt;p&gt;Precise location also requires a concept of longitude. How does one define longitude on a planet whose continents are constantly moving about? Greenwich, England as zero degrees longitude? Keep in mind that the rock underlying Greenwich formed a few hundred million years ago.&lt;/p&gt;&#xA;&lt;p&gt;With regard to the future, it's conjecture. When, where, in what shape, and even if the next supercontinent forms is unknown. Whether the Pacific continues to close and The Atlantic continues to expand is unknown.&lt;/p&gt;&#xA;" OwnerUserId="239" OwnerDisplayName="David Hammen" LastActivityDate="2020-08-30T21:17:15.973" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20148" PostTypeId="2" ParentId="20146" CreationDate="2020-08-30T21:46:54.920" Score="4" Body="&lt;p&gt;Please take a look at &lt;a href=&quot;http://www.scotese.com/Default.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;this website&lt;/a&gt;, Dr Scotese explains what methods we use to determine how the earth was in the past, and indeed, what it might do in the future. We can never be sure however. He has also posted numerous videos on You Tube.&lt;/p&gt;&#xA;&lt;p&gt;From Dr Scotese's website :&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The past positions of the continents can be determined using the&#xA;following five lines of evidence: paleomagnetism, linear magnetic&#xA;anomalies, paleobiogeography, paleoclimatology, and geologic history.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Paleomagnetism&lt;/strong&gt; is the study of the record of the Earth's magnetic field in rocks, sediment, or archeological materials. Magnetic minerals in rocks can lock-in a record of the direction and intensity of the magnetic field when they form. This record provides information on the past behavior of Earth's magnetic field and the past location of tectonic plates. The record of geomagnetic reversals preserved in volcanic and sedimentary rock sequences (magnetostratigraphy) provides a time-scale that is used as a geochronologic tool. By measuring the remanent magnetic field often&#xA;preserved in iron-bearing rock formations, paleomagnetic analysis can&#xA;determine whether a rock was magnetized near the Pole or near the&#xA;Equator. Paleomagnetism provides direct evidence of a continent's N-S&#xA;(latitudinal) position, but does not constrain its E-W (longitudinal)&#xA;position.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Linear Magnetic Anomalies.&lt;/strong&gt; The Earth's magnetic field has another&#xA;important property. Like the Sun's magnetic field, the Earth's&#xA;magnetic field &amp;quot;flips&amp;quot; or reverses polarity. Fluctuations, or&#xA;&amp;quot;anomalies&amp;quot;, in the intensity of the magnetic field, occur at the&#xA;boundaries between normally magnetized sea floor, and sea floor&#xA;magnetized in the &amp;quot;reverse&amp;quot; direction. The age of these linear&#xA;magnetic anomalies can be determined using fossil evidence and&#xA;radiometric age determinations. Because these magnetic anomalies form&#xA;at the mid-ocean ridges, they tend to be long, linear features (hence&#xA;the name &amp;quot;linear magnetic anomalies&amp;quot;) that are symmetrically disposed&#xA;about the ridges axes. The past positions of the continents during the&#xA;last 150 million years can be directly reconstructed by superimposing&#xA;linear magnetic anomalies of the same age.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Paleobiogeography.&lt;/strong&gt; The past distribution of plants and animals can&#xA;give important clues concerning the latitudinal position of the&#xA;continents as well as their relative positions. Cold-water faunas can&#xA;aften be distinguished from warm-water faunas, and ancient floras both&#xA;reflect paleo-temperature and paleo-rainfall. The similarity or&#xA;dissimilarity of faunas and floras on different continents can be used&#xA;to estimate their geographic proximity. In addition, the evolutionary&#xA;history of groups of plants and animals on different continents can&#xA;reveal when these continents were connected or isolated from each&#xA;other.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Paleoclimatology.&lt;/strong&gt; The Earth's climate is primarily a result of the&#xA;redistribution of the Sun's energy across the surface of the globe. It&#xA;is warm near the Equator and cool near the Poles. Wetness, or&#xA;rainfall, also varies systematically from the equator to the pole. It&#xA;is wet near the equator, dry in the subtropics, wet in the temperate&#xA;belts and dry near the poles. Certain kinds of rocks form under&#xA;specific climatic conditions. For example coals occur where it is wet,&#xA;bauxite occurs where it is warm and wet, evaporites and calcretes&#xA;occur where it is warm and dry, and tillites occur where it is wet and&#xA;cool. The ancient distribution of these, and other, rock types can&#xA;tell us how the global climate has changed through time and how the&#xA;continents have travelled across climatic belts.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Geologic and Tectonic History.&lt;/strong&gt; In order to reconstruct the past&#xA;positions of the continents it is necessary to understand the&#xA;development of the plate tectonic boundaries that separate continents&#xA;and bring them back together again. Only by understanding the regional&#xA;geological and tectonic evolution of an area can you determine the&#xA;location and timing of rifting, subduction, continental collision and&#xA;other major plate tectonic events.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="21003" OwnerDisplayName="Raffles" LastActivityDate="2020-08-31T22:21:38.570" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20149" PostTypeId="1" CreationDate="2020-09-01T13:17:24.720" Score="3" ViewCount="216" Body="&lt;p&gt;Oxygen molecules absorb UV Rays and are converted to elemental oxygen atoms. These elemental oxygen atoms combine with molecular oxygen to go give ozone .&lt;/p&gt;&#xA;&lt;p&gt;When there is so much oxygen present in atmosphere how will UV Rays reach us? Are we concerned about oxygen being depleted?&lt;/p&gt;&#xA;" OwnerUserId="21004" LastActivityDate="2020-09-01T14:40:28.057" Title="Why is ozone layer so important when oxygen atoms absorb UV Rays?" Tags="|ozone|stratosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20150" PostTypeId="2" ParentId="20149" CreationDate="2020-09-01T14:10:38.310" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Why is ozone layer so important when oxygen atoms absorb UV Rays?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The cross section of ozone to UV radiation is many, many orders of magnitude higher than is the cross section of &lt;span class=&quot;math-container&quot;&gt;$\text O_2$&lt;/span&gt; to UV radiation, so very much higher that despite the paucity of ozone molecules compared to diatomic oxygen molecules even in the stratosphere, it is the ozone molecules that tend to absorb incoming UV radiation.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;When there is so much oxygen present in atmosphere how will UV Rays reach us?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Oxygen has a low cross section to UV radiation. It absorbs some, but not very much.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Are we concerned about oxygen being depleted?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Not at all. Suppose the ozone content did become rather high compared to nominal. This would increase the rate at which ozone combines with monatomic oxygen to form to diatomic oxygen molecules. Ozone is a transient component of the atmosphere. It is constantly being created but is also constantly being destroyed.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2020-09-01T14:40:28.057" LastActivityDate="2020-09-01T14:40:28.057" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20151" PostTypeId="1" CreationDate="2020-09-01T17:53:33.147" Score="1" ViewCount="32" Body="&lt;p&gt;If two cyclones come together and orbit each other as per the &lt;a href=&quot;https://www.thoughtco.com/the-fujiwhara-effect-3443929&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fujiwhara Effect&lt;/a&gt;is there a way to calculate the change in pressure gradient that each will face?  If not, are there at least pressure gradient charts showing some previous cyclones that come together so that I could make an estimate of the changes?&lt;/p&gt;&#xA;" OwnerUserId="21006" LastActivityDate="2020-09-01T17:53:33.147" Title="Can we calculate the pressure gradient impact on two cyclones with the Fujiwhara effect?" Tags="|cyclone|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20156" PostTypeId="1" AcceptedAnswerId="20439" CreationDate="2020-09-03T02:16:55.540" Score="5" ViewCount="284" Body="&lt;p&gt;Understanding the behavior of particulates in the atmosphere is important for modeling climate, weather and public health. They can be nucleation sites for rain, fog and smog, they can have thermal impact due to absorption of sunlight and possibly radiation in thermal infrared, and the smallest can deposit chemicals deep inside our lungs.&lt;/p&gt;&#xA;&lt;p&gt;Their behavior can be characterized by their &lt;a href=&quot;https://en.wikipedia.org/wiki/Aerosol#Aerodynamic_diameter&quot; rel=&quot;nofollow noreferrer&quot;&gt;particulate aerodynamic diameter&lt;/a&gt;, one way to characterize their size according to their aerodynamic behavior.&lt;/p&gt;&#xA;&lt;p&gt;The rate at which particulate matter deposited in the atmosphere settle to the ground is a strong function of size. Throw a handful of sand into the air and it returns to the ground within second, create soot with fire and it rises in the column of hot air produced and may take weeks, months or even years before it returns to Earth.&lt;/p&gt;&#xA;&lt;p&gt;Of possible interest:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.nature.com/news/high-flying-bacteria-spark-interest-in-possible-climate-effects-1.12310&quot; rel=&quot;nofollow noreferrer&quot;&gt;High-flying bacteria spark interest in possible climate effects&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.sciencemag.org/news/2013/01/microbes-survive-and-maybe-thrive-high-atmosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;Microbes Survive, and Maybe Thrive, High in the Atmosphere&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.smithsonianmag.com/science-nature/living-bacteria-are-riding-earths-air-currents-180957734/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Living Bacteria Are Riding Earth’s Air Currents&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Is there any way to estimate at least approximately as a function of size the time it takes airborne particulates found high in the atmosphere to return to Earth, and which ones return due to gravity and which due to formation of precipitation? I know it's a complex topic and it may depend strongly on the altitude at which they start. Perhaps some rules-of-thumb or examples might be sufficient to get an idea of what's involved in such estimates. That may be helpful in order to formulate more specific follow-up questions.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2020-10-04T00:11:35.827" LastActivityDate="2020-11-05T02:49:26.947" Title="How to estimate the settling time of atmospheric particulates as a function of aerodynamic size?" Tags="|atmosphere|atmosphere-modelling|particulates|aerosol|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20157" PostTypeId="1" CreationDate="2020-09-03T08:38:56.800" Score="10" ViewCount="3699" Body="&lt;p&gt;This is obviously an imaginary question, but it seems like something computable (which I don't have the mathematical ability to do so unfortunately). P.S. I do not have in-depth knowledge about comet/asteroid/meteoroid/even any space object at all, so please correct me if I made any mistakes. Also, please answer the question considering the current state of the Earth, not a super-heated Earth.&lt;/p&gt;&#xA;&lt;p&gt;Some propositions:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The asteroid/comet is sizable, cold to the core, and is made up of materials with high heat capacity&lt;/li&gt;&#xA;&lt;li&gt;The asteroid/comet &amp;quot;strikes&amp;quot; the Earth at low speed&lt;/li&gt;&#xA;&lt;li&gt;The asteroid/comet strikes the Ocean&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Related: &lt;a href=&quot;https://astronomy.stackexchange.com/questions/8707/how-gently-could-a-comet-asteroid-meteorite-hit-earth&quot;&gt;How gently could a comet/asteroid/meteorite “hit” Earth?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3241" LastActivityDate="2020-09-07T11:54:35.787" Title="Could an icy/extremely-cold asteroid/comet ever strike and cool the Earth?" Tags="|climate-change|meteorite|asteroids|" AnswerCount="8" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20158" PostTypeId="2" ParentId="20157" CreationDate="2020-09-03T09:23:20.173" Score="13" Body="&lt;p&gt;No, it's not possible to cool the Earth with an asteroid impact.&lt;/p&gt;&#xA;&lt;p&gt;The mass of any asteroid that could hit the Earth is far too small to be a heat sink.  The &lt;a href=&quot;https://en.wikipedia.org/wiki/Chicxulub_impactor&quot; rel=&quot;noreferrer&quot;&gt;asteroid that killed the dinosaurs&lt;/a&gt; had a mass of around &lt;span class=&quot;math-container&quot;&gt;$10^{16}$&lt;/span&gt; kg.  The Earth has a mass of &lt;span class=&quot;math-container&quot;&gt;$10^{24}$&lt;/span&gt; kg, or a 100 million times more.  And no matter how cold an asteroid is, the kinetic energy released upon impact will be largely converted into heat.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2020-09-03T14:08:04.657" LastActivityDate="2020-09-03T14:08:04.657" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20159" PostTypeId="2" ParentId="20157" CreationDate="2020-09-03T09:25:25.277" Score="5" Body="&lt;p&gt;One asteroid or comet, no.&lt;/p&gt;&#xA;&lt;p&gt;Even it it was huge you might get a planetary extinction event like the meteorite that crashed into the Yucatan region resulting in the dinosaurs dying out. That would be due to the amount of dust and soil etc. that would be thrown into the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;The other thing, as the asteroid/comet/meteorite entered the Earth's atmosphere is would immediately start to heat up due to friction with the air. Some of the asteroid would be lost in the process.&lt;/p&gt;&#xA;&lt;p&gt;If the asteroid were to be made of&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;materials with high heat capacity&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;which might protect it against heating up while entering the atmosphere then the same material, acting as an excellent thermal insulator, would prevent the cold from the core of the asteroid from being released quickly. So no instant cooling.&lt;/p&gt;&#xA;&lt;p&gt;If the asteroid hit the ocean, water has a high thermal capacity. It is not going to rapidly freeze because a potentially very large super cold rock plopped into the ocean. There would be some localized short term cooling which would regain lost temperature fairly quickly.&lt;/p&gt;&#xA;&lt;p&gt;If an entire blizzard load of super cold rocks hit the Earth at the same time, the Earth's problem won't be with dealing with any cold it will be in dealing with all the dust raised into the atmosphere and the seismic shocks created by the rocks impacting the ground.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-09-03T09:25:25.277" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20160" PostTypeId="2" ParentId="20157" CreationDate="2020-09-03T09:33:53.653" Score="22" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Could an icy/extremely-cold asteroid/comet ever strike and cool the Earth?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;No.&lt;/p&gt;&#xA;&lt;p&gt;The smallest possible velocity is about 11 km/s velocity, and that would require a near miracle. For that to happen, the object would have to enter the vicinity of the Earth through a very small keyhole near the Sun-Earth L1 or L2 point with a very small velocity (a comet will not have that very small velocity), then be nearly ballistically captured by the Moon, and then fall to Earth. A comet would be more likely to hit the Earth at 40 km/s, or larger.&lt;/p&gt;&#xA;&lt;p&gt;And that means that it does not matter how cold or how hot the object was prior to impact. The kinetic energy of the impact will dwarf whatever thermal energy the object had prior to the impact.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-09-03T09:33:53.653" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20161" PostTypeId="2" ParentId="20157" CreationDate="2020-09-03T12:01:36.843" Score="21" Body="&lt;p&gt;I'm gonna sail against the wind and say &amp;quot;yes&amp;quot;, &lt;em&gt;indirectly&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Although you don't need a cold asteroid, a &amp;quot;normal&amp;quot; one would suffice. When striking the Earth, asteroids eject a large amount of dust into the atmosphere, blocking the Sun radiations, thus cooling the planet. The phenomenon is known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Impact_winter&quot; rel=&quot;noreferrer&quot;&gt;impact winter&lt;/a&gt; and is similar to volcanic and nuclear winters.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-09-03T12:01:36.843" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="20162" PostTypeId="2" ParentId="20110" CreationDate="2020-09-03T14:53:20.760" Score="3" Body="&lt;p&gt;Your graphic shows temperature anomalies. That is, an average temperature is calculated over a large time frame, say 15 ° C. Then each value on the graphic is the CHANGE from that average. Anomalies are nice because &amp;quot;inaccurate&amp;quot; measurement instruments (proxies) can be used. An absolute reading can be off but the reading to reading change will be much more accurate, and other inaccurate instruments can be combined.&#xA;Regarding precision and uncertainty. What your graphic is showing is an expected value, which can be as &amp;quot;precise&amp;quot; as you want it to be. It is only an expected value. Consider a pair of dice. The expected value is 7, but the roll of the dice can be anywhere from 2 to 12. Of more importance is uncertainty. This is not shown in your graphic. We &amp;quot;expect&amp;quot; a certain value but we are unsure as to exactly what we will measure each time. And now we get into probabilities and distributions. Another key to low uncertainty data is a lot of measurements or a lot of proxies.&#xA;Some examples of graphics with associated uncertainties are Marcott 2013, Loehle 2008, and Kaufman 2020. I believe Marcott uses 75 or so proxies. Of course present global temperature data use thousands of measurements, which drives down the uncertainty.&lt;/p&gt;&#xA;" OwnerUserId="21018" LastActivityDate="2020-09-03T14:53:20.760" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20163" PostTypeId="1" CreationDate="2020-09-03T16:50:49.910" Score="5" ViewCount="88" Body="&lt;p&gt;During the last years I have taken many pictures of obviously retreating glaciers and empty moraines in Greenland - just like this one. Looks devastating, actually.&#xA;In my understanding, the current retreat of the glaciers is due to anthropogenic climate change.&lt;/p&gt;&#xA;&lt;p&gt;(Picture taken about 500 km north of the polar circle on the Nussuaq peninsular, Greenland, August 2019)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WWBNk.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WWBNk.jpg&quot; alt=&quot;A Glacier in Greenland, Nussuaq peninsular, August 2019&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;When I have a look at the satellite image (screenshot from google earth) of 2016, the size of the glacier tongues seems plausible.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VpSBN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VpSBN.jpg&quot; alt=&quot;Screenshot 2016&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Looking at the satellite image from 1984 (it's also a screenshot from google earth), it irritates me that the differences in glacier extent in the satellite images seem to be relatively small.&#xA;Of course I know that the loss of mass of the ice is not only reflected in the shrinking area but also in the reduced thickness of the ice. What still irritates me is the fact that a massive retreat of the ice must have taken place before 1984.&lt;/p&gt;&#xA;&lt;p&gt;Local Greenlandic people told me that only a few generations ago, these glacier tongues were driven by dog sleds to go from valley to valley in winter when the sea was frozen over. That would not be possible today.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/buWgS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/buWgS.jpg&quot; alt=&quot;Screenshot 1984&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now I ask myself:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;are the satellite images from 1984 faulty?&lt;/li&gt;&#xA;&lt;li&gt;Did the essential retreat of the ice take place in the years of industrialization before 1984?&lt;/li&gt;&#xA;&lt;li&gt;Or did this retreat take place over a longer period of time in the history of the earth (&amp;quot;since the last ice age&amp;quot;)?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Thank you in advance for sharing your thoughts on this!&lt;/p&gt;&#xA;&lt;p&gt;PS: I've discovered the picture from 1984 via this time-travel function in Google Earth (Pro). I think the month (12) isn't correct because in winter there should be more snow visible. Maybe the month just isn't specified because all older pictures seem to default to December.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Uv1iu.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Uv1iu.png&quot; alt=&quot;Explanation 1984&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21020" LastEditorUserId="21020" LastEditDate="2020-09-04T04:47:54.463" LastActivityDate="2020-09-04T04:47:54.463" Title="Dynamic of glacier retreat? (here: in Greenland)" Tags="|climate-change|glaciology|arctic|greenland|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20165" PostTypeId="2" ParentId="20157" CreationDate="2020-09-03T20:38:24.090" Score="4" Body="&lt;h1&gt;Thermodynamically No&lt;/h1&gt;&#xA;&lt;p&gt;Jean-Marie gives a good answer about aerosol effects.  Others observe that impacts add energy to the planet.  I would simply like to look at the energy budget.&lt;/p&gt;&#xA;&lt;p&gt;The sun dumps on the order of &lt;a href=&quot;https://phys.org/news/2011-10-vast-amounts-solar-energy-earth.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;173 petawatts&lt;/a&gt; on the earth, nonstop.  Now, asteroids have a &lt;a href=&quot;https://www.lpi.usra.edu/meetings/lpsc2012/pdf/2626.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;heat capacity&lt;/a&gt; on the order of &lt;span class=&quot;math-container&quot;&gt;$10^{18} - 10^{24} J/K$&lt;/span&gt;, depending on size.  Note that a petawatt is &lt;span class=&quot;math-container&quot;&gt;$10^{15} J/s$&lt;/span&gt;.  Also note that the sun dumps &lt;span class=&quot;math-container&quot;&gt;$10^{18} W$&lt;/span&gt; on the planet every 5.8 s or so.&lt;/p&gt;&#xA;&lt;p&gt;Now, let's imagine we find an asteroid floating around interstellar space at a chilly 3 K (or colder or warmer...the exact number doesn't matter).  Let's further suppose we can chuck it at the earth and land it without any significant addition of energy (we use an alien tractor beam to gently lower it to the surface).  This asteroid will &amp;quot;cool&amp;quot; the earth by heating itself up.  So...how much cooling should we expect?&lt;/p&gt;&#xA;&lt;p&gt;Instead of pretending that the earth is a lone ice box floating in space, and calculating what happens when we drop a large ice cube into it, I think it's more useful to simply ask: &amp;quot;How quickly will the sun melt our ice cube?&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;The sun will contribute enough energy to warm the asteroid by 1 K every 6s or so, for a small asteroid.  To raise the asteroid from 3 K to earth mean surface temperature of 288 K will take somewhat less than 1800 s, or about 30 minutes.  That's about how long an ice cube would last in a chilled beverage on a not particularly warm day.&lt;/p&gt;&#xA;&lt;p&gt;Now, that is roughly equivalent to turning off the sun for 30 minutes.  That would have a noticeable effect on global weather, but I doubt it would remain noticeable even a few days after.  Over the course of a year, this blip would amount to a solar energy reduction of 0.005%.  Hardly enough to detect in the climate record.&lt;/p&gt;&#xA;&lt;p&gt;Of course, we picked the smallest asteroid for the initial calculation.  If you go towards the large end, you can crank up all these numbers by a factor of a million, more or less.  Ceres, for instance, would suck up about 5000% of the sun's annual energy sent to earth.  That's 50 years of solar energy, and obviously a significant impact.  Given that it's round, we can debate whether Ceres counts as an &amp;quot;asteroid&amp;quot; or not.  &lt;a href=&quot;https://en.wikipedia.org/wiki/44_Nysa&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nysa&lt;/a&gt; is more &amp;quot;asteroid-shaped&amp;quot;, but only has about 100x the heat capacity of our initial calculations.  So, a solar dip of 0.5% over the course of a year might be enough to notice, but likely not enough to cause attributable long-term climate effects (given that the Milankovitch cycles produce larger variance).&lt;/p&gt;&#xA;&lt;p&gt;Note that if you start with a more typical asteroid temperature of about 200 K, you would reduce all the energy budget numbers to about 1/3 of their value (meaning, the smallest ice cube would melt in ~10 minutes).&lt;/p&gt;&#xA;" OwnerUserId="21024" LastActivityDate="2020-09-03T20:38:24.090" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20166" PostTypeId="2" ParentId="20157" CreationDate="2020-09-03T21:21:29.240" Score="12" Body="&lt;p&gt;For your purpose (energy in the entire system) it doesn't matter if the asteroid lands gently or not because energy is conserved: If the asteroid slows through some kind of atmospheric braking, then the energy goes into the atmosphere as heat. If it slows through running into the ocean at full tilt then the energy goes into the ocean as heat. If the energy goes into the asteroid but it raises the temperature to higher than the atmospheric temperature, the asteroid will radiate the extra heat away into the atmosphere over time anyway.&lt;/p&gt;&#xA;&lt;p&gt;Let's say the asteroid starts off as cold as it's possible to get, 0 degrees Kelvin, and the average global temperature is just about 285K. We will leave the material as a question mark for now, but call the specific heat capacity c. The energy that our asteroid can absorb before it becomes warmer than the average atmospheric temperature is (in Joules):&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$m \cdot \Delta t \cdot c = m\, \mathrm{kg} \cdot 285\, \mathrm{K} \cdot c\,\mathrm{J}\,\mathrm{kg}^{-1}\mathrm{K}^{-1}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Since the escape velocity of Earth is 11 km/s (11000 m/s) the total energy coming in (in kg m^2/s^2 aka Joules) will be:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{1}{2}mv^2 = \frac{1}{2}  m \mathrm{kg} \cdot 11000^2 \,\mathrm{m^2}\mathrm{s^{-2}}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;We want our asteroid to be capable of absorbing more energy than the energy it has from falling:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$m \mathrm{kg} \cdot 285 \mathrm{K} \cdot c\mathrm{J}\,\mathrm{kg}^{-1}\mathrm{K}^{-1} &amp;gt; \frac{1}{2} m \mathrm{kg} \cdot 11000^2 \,\mathrm{m^2}\mathrm{s^{-2}}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Mass cancels out immediately and after some arithmetic, we end up with (rounding quite a bit) c &amp;gt; 200,000 J/kg K.&lt;/p&gt;&#xA;&lt;p&gt;Unfortunately, the material with the highest specific heat is hydrogen, with a specific heat of about 14,000 J/kg K, which is nowhere near what we need.&lt;/p&gt;&#xA;&lt;p&gt;Short answer: No.&lt;/p&gt;&#xA;" OwnerUserId="13310" LastEditorUserId="9563" LastEditDate="2020-09-07T11:54:35.787" LastActivityDate="2020-09-07T11:54:35.787" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20167" PostTypeId="2" ParentId="20157" CreationDate="2020-09-04T03:32:02.363" Score="0" Body="&lt;p&gt;While comets are cold out in space they dissipate as they get closer to the sun and earth. Upon contact with the atmosphere they burn up. If a comet is large enough bolide they may possess the same climatological concerns as the Cretaceous asteroid impact&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-09-04T03:32:02.363" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20168" PostTypeId="2" ParentId="18854" CreationDate="2020-09-04T03:38:43.633" Score="1" Body="&lt;p&gt;The Accumulation of organic detritus begins when a structure is abandoned or poorly maintained. Plants that thrive without soil (epiphytes, lithophytes) are often the first generation of plants. As they die, new ones take their place and the first layer of accumulated biomass builds to accommodate more sophisticated plants grow in this medium&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-09-04T03:38:43.633" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20169" PostTypeId="2" ParentId="15580" CreationDate="2020-09-04T03:58:40.923" Score="0" Body="&lt;p&gt;One book &amp;quot;Introduction to Wildland fire&amp;quot;  by Stephen J. Andrews&lt;/p&gt;&#xA;&lt;p&gt;The area burned in California has declined over 80% since Europeans arrived. And that’s not necessarily a good thing.&lt;/p&gt;&#xA;&lt;p&gt;Prehistoric annual average acres burned: 4,447,897. 2010-2019 average acres burned: 775,325.&#xA;Xeric climate ecosystems that depend on periodic fires are essential to regenerating those environments.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The smoke of the fire bakes cones and seed pods to finally release their seeds or stimulate seeds to germinate&lt;/li&gt;&#xA;&lt;li&gt;the fire produces ethylene gas which stimulates growth of new plants&lt;/li&gt;&#xA;&lt;li&gt;the fire itself cleared weedy competition permitting fire tolerant plants that normally survive, to continue&lt;/li&gt;&#xA;&lt;li&gt;The ashes provide a soluable nutrient rich dressing. In dryer forests decomposition is a slower process.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="21028" LastEditorUserId="21028" LastEditDate="2020-09-05T01:46:34.577" LastActivityDate="2020-09-05T01:46:34.577" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20171" PostTypeId="1" CreationDate="2020-09-05T05:51:52.347" Score="4" ViewCount="13255" Body="&lt;p&gt;Why does the same temperature feel hotter at night? For example, 70 degrees literally feels hot at night when outside but during the day 70 degrees feels just mild when outside. Why is that? And another example is that it feels hotter at night in your house during the summer than during the day and why is that when it is hotter outside during the day and cooler at night but the opposite when inside your house?&lt;/p&gt;&#xA;" OwnerUserId="17923" LastEditorUserId="6467" LastEditDate="2023-02-01T14:41:17.107" LastActivityDate="2023-02-03T02:33:43.980" Title="Why does it feel hotter at night?" Tags="|temperature|geothermal-heat|" AnswerCount="5" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20173" PostTypeId="2" ParentId="20157" CreationDate="2020-09-06T04:30:01.050" Score="1" Body="&lt;p&gt;Impacts typically occur at a range of 20 to 70 km/s.&lt;/p&gt;&#xA;&lt;p&gt;Let's look at the 20 km/s one.&lt;/p&gt;&#xA;&lt;p&gt;1 kg of mass at 20 km/s = 1kg * 20,000 m/s * 20,000m/s /2 = 200 million joules.&lt;/p&gt;&#xA;&lt;p&gt;To bring ice from absolute zero to melting point requires 1000 * 273 * 0.5 = 136 thousand joules.  Yes, melting it will take energy and so will vapourization, but this is VERY small potatoes compared to the kinetic energy.  (Water ice is the largest part of comet ice.  Ammonia has a somewhat higher specific heat, methane, far lower.)&lt;/p&gt;&#xA;&lt;p&gt;So as a source of coolth, a comet impact doesn't rate.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;So let's instead, invite Archanangel Gabriel to come down and gently lay the comet down to melt and chill the area.&lt;/p&gt;&#xA;&lt;p&gt;Large comet 20 km diameter.  Assume solid ice for the sake of simplicity.  20 km sphere is  4/3 * pi * 10^3  = about 4200 cubic km of ice.&lt;/p&gt;&#xA;&lt;p&gt;Wow.  Lots of ice cubes for my martini!&lt;/p&gt;&#xA;&lt;p&gt;Comparison:  Canada has an area of 10 million km2.   If you had 1/10 of a meter of ice (4 inches...) you would have 1/10,000 of a km * 10 million km = 1000 km3.  So your comet has about the four times the chilling effect as spring in Canada. (Ok, 10 cm is arbitrary.)&lt;/p&gt;&#xA;&lt;p&gt;Or the same as 40 cm of ice on Canada.&lt;/p&gt;&#xA;&lt;p&gt;Now a square meter with 40 cm of ice would be about 400 kg. (Please, do NOT muddle the waters with the different density of water and ice.  This is a BOTE calc.)&lt;/p&gt;&#xA;&lt;p&gt;1 kg of ice takes about 500 kJ to melt, assuming it's starting from close to absolute zero.  400 kg takes 200,000 kJ&lt;/p&gt;&#xA;&lt;p&gt;Solar constant is about 1 kW/m2 at noon.  (Yes this is variable depending on latitude, time of year, cloud cover, and things that otherwise were thought only to affect the flavour of pizza) So 200,000 seconds of noonday sun would melt the ice.  About 55 hours.&lt;/p&gt;&#xA;&lt;p&gt;Which would be about 200 hours due to night, and low angles.  8 days.  Ish.&lt;/p&gt;&#xA;&lt;p&gt;However Canada isn't the whole world.  Only about 1/50 of it.  so 8/50 or about 4 hours sunlight over the earth to melt the comet.&lt;/p&gt;&#xA;&lt;p&gt;Like throwing an ice cube from your drink into a campfire.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;You're left with nuclear winter possibilities.  Others have addressed that.&lt;/p&gt;&#xA;" OwnerUserId="13145" LastActivityDate="2020-09-06T04:30:01.050" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20174" PostTypeId="2" ParentId="20145" CreationDate="2020-09-06T17:38:25.710" Score="0" Body="&lt;p&gt;I understand the term &amp;quot;four-way closure&amp;quot; to be a dome (structural). If that is what you mean...&lt;/p&gt;&#xA;&lt;p&gt;In that case the 2 structures are similar, but domes are rather symmetrical, whiles anticlines are very asymmetrical, to the extend that we only consider them having to limbs. Although technically speaking anticlines have four, just like domes. Those limbs are called periclines. It's all just convention, both four-way closures and anticlines are folded structures that have an &amp;quot;ending&amp;quot; at some point, it's just that four-way closures are more symmetrical.&lt;/p&gt;&#xA;" OwnerUserId="20834" LastActivityDate="2020-09-06T17:38:25.710" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20175" PostTypeId="1" CreationDate="2020-09-07T03:54:07.187" Score="4" ViewCount="82" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;It was so cold that frost formed inside trees in the middle of summer.&#xA;Traces of this have been found in Russia, among other places. It is very rare for trees to freeze internally during the summer.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://sciencenorway.no/archaeology-climate-cultural-history/the-long-harsh-fimbul-winter-is-not-a-myth/1613223&quot; rel=&quot;nofollow noreferrer&quot;&gt;The long, harsh Fimbul winter is not a myth&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;How would this freezing leave a &amp;quot;trace&amp;quot;?&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2020-10-18T09:06:40.547" Title="Frost in trees in the middle of summer (of 536)" Tags="|volcanology|paleoclimatology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20176" PostTypeId="1" CreationDate="2020-09-07T04:24:29.953" Score="3" ViewCount="656" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;The Major Lunar Standstill, as the cycle is called, has been followed by serious starwatchers since the Babylonians. Like clockwork every 18.6 years, it triggers severe tide spikes, swells, and floods, especially in the tropics. Now, the charts showed that the Standstill was messing with Jakarta. Around Nov. 26 or 27, just a few months away, Brinkman told Abidin and Andreas, Jakarta appeared all but certain to experience a devastating new flood — a surge that would send a half foot of seawater or more over the wall and into the city.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://gen.medium.com/the-fastest-sinking-city-in-the-world-has-a-plan-to-save-itself-5f3ce623bd45&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Radical Plan to Save the Fastest Sinking City in the World&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Wikipedia has a &lt;a href=&quot;https://en.wikipedia.org/wiki/Lunar_standstill#:%7E:text=One%20major%2C%20or%20one%20minor,and%20moonset%2C%20reaches%20a%20maximum.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lunar Standstill&lt;/a&gt; article but it does not mention tides, and I cannot find (good quality) &lt;a href=&quot;http://google.com/search?q=%22Major%20Lunar%20Standstill%22%20tide&quot; rel=&quot;nofollow noreferrer&quot;&gt;pages that make this connection&lt;/a&gt; .&lt;/p&gt;&#xA;&lt;p&gt;Can a &amp;quot;Major Lunar Standstill&amp;quot; cause one-day high tides as described in the Jakarta article?&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2020-09-08T06:28:38.157" Title="&quot;Major Lunar Standstill&quot; causing high tides?" Tags="|tides|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20178" PostTypeId="2" ParentId="20117" CreationDate="2020-09-08T00:23:43.097" Score="5" Body="&lt;p&gt;As mentioned in a comment to another answer, the terms &amp;quot;basic&amp;quot; and &amp;quot;acid&amp;quot; in relation to igneous rocks are outdated and stem from an incomplete understanding of rock chemistry in the past.&lt;/p&gt;&#xA;&lt;p&gt;Better terms are &amp;quot;ultramafic&amp;quot;, &amp;quot;mafic&amp;quot;, &amp;quot;felsic&amp;quot;, etc.&#xA;As to your question - why aren't there &amp;quot;ultrafelsic&amp;quot; rocks? Let's put it into more quantitative numbers.&lt;/p&gt;&#xA;&lt;p&gt;Felsic rocks (or acid, in the old terminology) are rocks with high SiO&lt;sub&gt;2&lt;/sub&gt; content, usually higher than 60% or 65%. Your hypothetical &amp;quot;ultrafelsic&amp;quot; rocks would then have maybe 85% or 90% SiO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The reason rocks like that form is because crystals with low SiO&lt;sub&gt;2&lt;/sub&gt; contents are removed from the melt, enriching the residual melt in SiO&lt;sub&gt;2&lt;/sub&gt; and push them to the &amp;quot;felsic&amp;quot; field.&lt;/p&gt;&#xA;&lt;p&gt;At some point, the melt is sufficiently rich in SiO&lt;sub&gt;2&lt;/sub&gt; and quartz becomes a mineral that forms from the melt. Quartz is 100% SiO&lt;sub&gt;2&lt;/sub&gt;, so it stops the melt from becoming richer in SiO&lt;sub&gt;2&lt;/sub&gt;. If by some act of magic the melt reaches 90% SiO&lt;sub&gt;2&lt;/sub&gt;, it simply crystallises more solid quartz, removing the excess SiO&lt;sub&gt;2&lt;/sub&gt; from the melt, and lowering it to more reasonable ~75%.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="2470" LastEditDate="2022-10-31T17:12:02.620" LastActivityDate="2022-10-31T17:12:02.620" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20179" PostTypeId="2" ParentId="20176" CreationDate="2020-09-08T06:28:38.157" Score="4" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Can a &amp;quot;Major Lunar Standstill&amp;quot; cause one-day high tides as described in the Jakarta article?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Possibly &amp;quot;fake news&amp;quot;, but very possibly yes.&lt;/p&gt;&#xA;&lt;p&gt;The possibly &amp;quot;fake news&amp;quot; part first: The next major lunar standstill will be in late 2024 / early 2025. The most recent minor lunar standstill was in 2015. There is no lunar standstill, major or minor, in 2020.&lt;/p&gt;&#xA;&lt;br&gt;&#xA;Now for the possibly yes part. The Moon and the Sun excite tides in the Earth's oceans at a variety of frequencies. The dominant frequency in most places is the M&lt;sub&gt;2&lt;/sub&gt; tidal component with a frequency of 12 hours and 25.2 minutes. This is due to the Moon, whose tidal influence is over twice that of the Sun. There are many other components to the tides. The longest modeled term, the lunar nodal tidal cycle, has a period of 18.61 years.&#xA;&lt;p&gt;Each of those exciting frequencies results in a set of &lt;a href=&quot;https://www.e-education.psu.edu/earth540/content/c6_p1.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;amphidromic systems&lt;/a&gt;. (Note: The linked site discusses the response to the M&lt;sub&gt;2&lt;/sub&gt; tidal component. Every tidal component results in its own set of amphidromic systems.) The 18.61 year period lunar nodal tidal cycle results in rather weak tides in general, typically less than a centimeter.&lt;/p&gt;&#xA;&lt;p&gt;That said, the very long frequency means that this generally small tide can add insult to injury when shorter frequency tides line up to create very high spring tides. Moreover, the shape of continents and the depths of the oceans can make what are normally small tidal influences have locally magnified significance. Miami, for example, experiences annual &lt;a href=&quot;https://www.miamigov.com/Government/ClimateChange/King-Tides&quot; rel=&quot;nofollow noreferrer&quot;&gt;king tides that flood low-lying parts of the city&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;More to the point, &lt;a href=&quot;https://noc.ac.uk/news/highest-tides-186-years&quot; rel=&quot;nofollow noreferrer&quot;&gt;many places along the UK coastline experienced the highest tide for 18.6 years between the 19th and 30th of September&lt;/a&gt;. Even more to the point, &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018JC014695&quot; rel=&quot;nofollow noreferrer&quot;&gt;tide gauge records have shown that the 18.61 year period lunar nodal tidal cycle can change high water levels by up to 30 cm&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;What about the fact that there is no lunar standstill in 2020? There are a few places experience the M&lt;sub&gt;2&lt;/sub&gt; appears to be exactly in sync with the Moon in that high tide happens when the Moon is at zenith / underfoot, low tide when the Moon is at the horizon. But it's the other way around in other places: High tide happens when the Moon is at the horizon. In yet other places, high tide happens when the Moon is halfway up in the sky.&lt;/p&gt;&#xA;&lt;p&gt;The amphidromic systems that result from tidal forcings result in rotating waves about amphidromic points. Places do not in general experience high tide when the Moon is at zenith. Every place instead experiences a phase shift from when one would naively expect high tide to occur. With the 18.613 year lunar nodal tidal cycle, that phase shift could be as much as ±9.31 years. A peak lunar nodal tidal four years before a major lunar standstill is well within the realm of the possible.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-09-08T06:28:38.157" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20180" PostTypeId="1" AcceptedAnswerId="20182" CreationDate="2020-09-08T08:53:46.043" Score="1" ViewCount="685" Body="&lt;p&gt;I refer to this question, I asked recently in the physics board:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://physics.stackexchange.com/questions/578308/doesnt-increase-of-potential-temperature-with-height-contradict-adiabatic-natur&quot;&gt;https://physics.stackexchange.com/questions/578308/doesnt-increase-of-potential-temperature-with-height-contradict-adiabatic-natur&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It doesn't make sense to type it again, so I link to it.&#xA;Maybe the question can be answered here.&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2020-09-08T11:19:08.233" LastActivityDate="2020-09-08T15:51:44.277" Title="Doesn't Increase of Potential Temperature with Height contradict Adiabatic Nature of Processes within Troposphere?" Tags="|atmosphere|temperature|atmosphere-modelling|troposphere|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20181" PostTypeId="2" ParentId="20180" CreationDate="2020-09-08T13:57:27.563" Score="4" Body="&lt;p&gt;If we'd be living in a dry atmosphere your reasoning is indeed correct. Air would rise adiabatically and air would loose about 9.8 °C/km (dry adiabatic lapse rate). This means constant potential temperature. However, Earths atmosphere isn't dry. As soon as a rising, moist air parcel reaches saturation, it will rise with a moist adiabatic lapse rate (6-7 °C/km). Potential temperature will rise (because if the parcel falls down again it will be warmer at the same level - see below). This causes clouds and sometimes rain and thus, reduces the overall water content in an air parcel.&lt;/p&gt;&#xA;&lt;p&gt;If such a parcel is now going to fall again it will gain temperature according to the dry adiabatic lapse rate (because it lost water during ascension). Lets say initially a parcel starts rising with moist adiabatic lapse rate with temperature &lt;span class=&quot;math-container&quot;&gt;$T(t=0)$&lt;/span&gt; and then falls down again and reaches the same level at &lt;span class=&quot;math-container&quot;&gt;$t=1$&lt;/span&gt;. You will then observe that &lt;span class=&quot;math-container&quot;&gt;$T(t=0)&amp;lt; T(t=1)$&lt;/span&gt;. Thus, potential temperature must have increased as the parcel was rising.&lt;/p&gt;&#xA;" OwnerUserId="18833" LastEditorUserId="18833" LastEditDate="2020-09-08T15:47:38.420" LastActivityDate="2020-09-08T15:47:38.420" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20182" PostTypeId="2" ParentId="20180" CreationDate="2020-09-08T15:51:44.277" Score="4" Body="&lt;p&gt;You may be forgetting that pressure also decreases with height (exponentially). Also, because &lt;span class=&quot;math-container&quot;&gt;$P=\rho R T$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\frac{dP}{dT}=\rho R$&lt;/span&gt; (that is, &lt;span class=&quot;math-container&quot;&gt;$c_p$&lt;/span&gt; does not appear). But I digress in answering your question.&lt;/p&gt;&#xA;&lt;p&gt;Let's break down why potential temperature increases with height. Let's start with the equation: &lt;span class=&quot;math-container&quot;&gt;$$\theta=T\left(\frac{P_0}{P}\right)^{\frac{R_d}{c_p}}\tag{1}$$&lt;/span&gt; Now, if we want to ask why &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; increases with height, let's rephrase &lt;span class=&quot;math-container&quot;&gt;$(1)$&lt;/span&gt; as a function of height:  &lt;span class=&quot;math-container&quot;&gt;$$\theta(z)=T(z)\left[\frac{P_0}{P(z)}\right]^{\frac{R_d}{c_p}}\tag{2}$$&lt;/span&gt; Now if you follow &lt;a href=&quot;https://earthscience.stackexchange.com/questions/19517/derivative-of-exner-function/19519#19519&quot;&gt;my derivation&lt;/a&gt; for finding &lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial \theta}{\partial z}=\frac{\theta}{T}\left(\frac{\partial T}{\partial z}+\frac{g}{c_p}\right)$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;You may note that the &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial\theta}{\partial z}=0$&lt;/span&gt; iff. &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial T}{\partial z}=-\frac{g}{c_p}=-9.8 \textrm{ K km}^{-1}$&lt;/span&gt; (dry adiabatic lapse rate). If &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial T}{\partial z}&amp;gt;-\frac{g}{c_p}$&lt;/span&gt; then &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial \theta}{\partial z}&amp;gt;0$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;This does not mean that the parcel is not adiabatic, though. For a parcel to be truly adiabatic, &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial \theta}{\partial t}+u\frac{\partial \theta}{\partial x}+v\frac{\partial \theta}{\partial y}+w\frac{\partial \theta}{\partial z}=0$&lt;/span&gt; Therefore, the only time a certain location can be considered adiabatic and have &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial \theta}{\partial z}=0$&lt;/span&gt; is when there is no heating (&lt;span class=&quot;math-container&quot;&gt;$\frac{\partial \theta}{\partial t}=0$&lt;/span&gt;), and no horizontal advection of &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; (&lt;span class=&quot;math-container&quot;&gt;$u\frac{\partial \theta}{\partial x}+v\frac{\partial \theta}{\partial y}=0$&lt;/span&gt;). Note, I did not exclude vertical advection of &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt;, because that is implied in the condition that &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial \theta}{\partial z}=0$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I'll also take pause here and list a few diabatic processes, and why there may be some justification to ignore them for your mental image.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Radiation: with the exception of greenhouse gases, the atmosphere is mostly transparent.&lt;/li&gt;&#xA;&lt;li&gt;Surface heating/ turbulent transport: more important near the surface (note that &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; is a minimum at the surface).&lt;/li&gt;&#xA;&lt;li&gt;Clouds/microphysical processes: discrete and are never everywhere all the time and moisture is a completely separate variable that varies all the time. There is a way around that (to some extent- the &lt;a href=&quot;https://en.wikipedia.org/wiki/Equivalent_potential_temperature#:%7E:text=%2C%20is%20a%20quantity%20that%20is,condenses%20during%20that%20pressure%20change.&quot; rel=&quot;nofollow noreferrer&quot;&gt;equivalent potential temperature&lt;/a&gt;, for latent heat exchange).&lt;/li&gt;&#xA;&lt;li&gt;Chemical processes: See below about how I remember &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; increases with height.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;hr&gt;&#xA;&lt;p&gt;If you want a good reminder of why &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; increases with height, it might be easier to remember that  &lt;span class=&quot;math-container&quot;&gt;$sgn \left( \frac{\partial \theta}{\partial z}\right)$&lt;/span&gt; is a good indicator of static stability. And thunderstorms need to stop at some point, even if that is the tropopause (where &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial \theta}{\partial z}&amp;gt;0$&lt;/span&gt; due to ozone heating).&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-09-08T15:51:44.277" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20183" PostTypeId="2" ParentId="14476" CreationDate="2020-09-08T22:01:45.793" Score="1" Body="&lt;p&gt;A solid to solid transition can occur between two enantiotropically related polymorphs without going through a melt. Whereas for monotropes conversion can only take place once the material has melted.  In other words the transition temperature between enantiotropically related polymorphs is below the melt of the lower temperature melting polymorph whereas for monotropically related polymorphs the transition temperature is above it.&lt;/p&gt;&#xA;" OwnerUserId="21050" LastActivityDate="2020-09-08T22:01:45.793" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20184" PostTypeId="1" CreationDate="2020-09-08T22:03:15.550" Score="3" ViewCount="63" Body="&lt;p&gt;I'm looking for the climate classification among the many different climate classification systems covering my absolute favorite form of climate. If a classification for this doesn't exist, and you happen to know of some places with this form of climate, a few places would work great as well!&lt;/p&gt;&#xA;&lt;p&gt;By the way, I'm asking this here as I haven't found any places like this yet, but I'm really hoping to!&lt;/p&gt;&#xA;&lt;p&gt;Conditions:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Snowy winters (1-5 m or 3-15 ft of snow) averaging between -5°C and 10°C (20°F to 50°F)&lt;/li&gt;&#xA;&lt;li&gt;Low-humidity summers averaging between 10°C and 35°C (50°F to 95°F)&lt;/li&gt;&#xA;&lt;li&gt;Decent amount of rain (but preferably not in winter), meaning no extended dry season&lt;/li&gt;&#xA;&lt;li&gt;Coastal, ideally along an ocean, but along a very large lake works too&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;With the exception of the last condition, which only makes sense if someone happens to have places in mind instead of climate classifications, I've looked into all of these with existing climate classification systems and struggled to find a category that really captures them all:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Holdridge life zones&lt;/strong&gt; put this somewhere between &lt;em&gt;boreal moist forest&lt;/em&gt;, &lt;em&gt;boreal wet forest&lt;/em&gt;, &lt;em&gt;cool temperature moist forest&lt;/em&gt;, &lt;em&gt;cool temperate wet forest&lt;/em&gt;, &lt;em&gt;warm temperature moist forest&lt;/em&gt;, and &lt;em&gt;wet temperature wet forest&lt;/em&gt; but don't really capture the summer-winter gradient very well&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Trewartha climate classification&lt;/strong&gt; seems to have a few options that could cover this climate. &lt;em&gt;Cs&lt;/em&gt;, &lt;em&gt;Do&lt;/em&gt;, and &lt;em&gt;Dca&lt;/em&gt; seem to fit best, with optional &lt;em&gt;ak&lt;/em&gt;, &lt;em&gt;ao&lt;/em&gt;, &lt;em&gt;bk&lt;/em&gt;, or &lt;em&gt;bo&lt;/em&gt; suffixes for the universal thermal scale&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Köppen climate classification&lt;/strong&gt; puts this somewhere in &lt;em&gt;Cfa&lt;/em&gt;, &lt;em&gt;Cfb&lt;/em&gt;, &lt;em&gt;Csa&lt;/em&gt;, &lt;em&gt;Dfa&lt;/em&gt;, &lt;em&gt;Dfb&lt;/em&gt;, &lt;em&gt;Dsa&lt;/em&gt;, and &lt;em&gt;Dsb&lt;/em&gt;, but again it doesn't seem like all the nuance is captured. It probably doesn't help that I'm the least familiar with this system, and after spending a solid half hour looking into the various classifications and their criteria I ended up with a list covering about a quarter of all possible classifications under this system&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;h3&gt;Edit&lt;/h3&gt;&#xA;&lt;p&gt;I was a little unclear in explaining the temperature ranges above. To clarify, I'm looking for &lt;em&gt;average&lt;/em&gt; winter temperatures between around -5°C and 10°C, and &lt;em&gt;average&lt;/em&gt; summer temperatures between around 10°C and 35°C. I didn't mean for those to be interpreted as absolute bounds on possible temperatures, which would be fairly difficult to find given the small winter range and large summer range. To prevent future misinterpretation, I've added the word &lt;em&gt;averaging&lt;/em&gt; to the first two bullet points above.&lt;/p&gt;&#xA;" OwnerUserId="7287" LastEditorUserId="7287" LastEditDate="2020-09-10T13:40:03.070" LastActivityDate="2020-09-10T13:40:03.070" Title="Looking for the climate classification for a particular climate" Tags="|climate|temperature|models|geography|precipitation|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="20185" PostTypeId="1" CreationDate="2020-09-09T07:59:28.397" Score="2" ViewCount="81" Body="&lt;p&gt;So let's take the tropical rainforests of Earth for an example. The Congo, Amazon, Indonesia, Malaysia, and wherever else it may grow. Are all these aforementioned places considered parts of one biome, the tropical rainforest? Or are the Amazon Congo and etc. all just considered their own biomes which just happen to share the same biome type (in this case the tropical rainforest)?&lt;/p&gt;&#xA;" OwnerUserId="21052" LastActivityDate="2021-02-07T11:07:40.797" Title="What exactly are singular biomes as units?" Tags="|ecology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20186" PostTypeId="1" CreationDate="2020-09-10T04:27:16.353" Score="7" ViewCount="325" Body="&lt;p&gt;Looking at different world maps, I noticed that there is considerable variety in how the coastline of Antarctica is depicted (even when taking the different map projections into consideration).&lt;/p&gt;&#xA;&lt;p&gt;Are these discrepancies caused by the fact that the coastline of Antarctica has not been precisely mapped because the ice sheet obscures it in satellite and aerial photography? Do we have the technology to look through the ice sheet and locate the bedrock and has it been used on every part of Antarctica's coastline, or does map data still contain some guess work and interpolation?&lt;/p&gt;&#xA;&lt;p&gt;Or are there perhaps competing ideas about how a coastline covered in ice should be outlined on a map? I noticed e.g. that Google Maps displays &lt;a href=&quot;https://en.wikipedia.org/wiki/Berkner_Island&quot; rel=&quot;noreferrer&quot;&gt;Berkner Island&lt;/a&gt; while Wikipedia claims that the island's bedrock is completely below sea-level.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Examples: Google Maps has a very different outline for the islands under the Filchner-Ronne ice shelf than other sources:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yAQ9P.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yAQ9P.png&quot; alt=&quot;Google Maps&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;example 1: from Google Maps&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BkAKX.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BkAKX.png&quot; alt=&quot;Other Map&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;example 2: from an example using the D3-Geo-Projection code library (not sure where the dataset is from)&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PNxDT.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PNxDT.png&quot; alt=&quot;from Wikipedia's Antarctica article&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;example 3: from Wikipedia's Antarctica article (similar to example 2, but using a very different projection)&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="21059" LastEditorUserId="21059" LastEditDate="2020-09-10T05:37:04.713" LastActivityDate="2021-03-12T07:22:34.673" Title="Has Antarctica's coastline been completely mapped? (map discrepancies)" Tags="|geography|mapping|ice-sheets|antarctica|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20187" PostTypeId="2" ParentId="20185" CreationDate="2020-09-10T10:42:01.370" Score="1" Body="&lt;p&gt;I guess it depends on which biome classification you use (there are several), but yes, usually tropical forests of Amazonia, Africa &amp;amp; Asia are classified within the same biome. For instance if you take the WWF classification made by &lt;a href=&quot;https://doi.org/10.1641/0006-3568(2001)051%5B0933:TEOTWA%5D2.0.CO;2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Olson et al. (2001)&lt;/a&gt;, which has 14 terrestrial biomes, they all fall in the &amp;quot;Tropical and subtropical moist broadleaf forests&amp;quot; biome, in green in their figure 1:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ayykw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ayykw.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The ecoregions are categorized within 14 biomes and eight biogeographic realms to facilitate representation analyses.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It means they share some global characteristics in terms of climate, vegetation... (described &lt;a href=&quot;https://www.worldwildlife.org/biomes/tropical-and-subtropical-moist-broadleaf-forests&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;), but they also have some differences. To see these differences, you have to go to a lower level than biomes: ecoregions. The same study divided the world into 867 ecoregions, that are mostly based on the distribution of species.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-09-10T10:42:01.370" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20188" PostTypeId="2" ParentId="20186" CreationDate="2020-09-10T13:32:37.937" Score="-2" Body="&lt;p&gt;What you are seeing is mostly different projections. Look at the last two images. The penultimate image has latitude lines that are straight and parallel to one another, longitude lines that are straight and parallel to one another, and the latitude and longitude are orthogonal to one another. The latitude lines are curved in the last image. The longitude lines, which aren't shown in the latter image, would not be parallel in this protection.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-09-10T13:32:37.937" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20189" PostTypeId="1" AcceptedAnswerId="20194" CreationDate="2020-09-10T20:49:56.463" Score="1" ViewCount="74" Body="&lt;p&gt;I see lots U.S. wildfires on &lt;a href=&quot;https://zoom.earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zoom Earth&lt;/a&gt;, and lots news about them. Is this amount of wildfires normal? Or is this average? If over average, why?&lt;/p&gt;&#xA;" OwnerDisplayName="user17042" LastActivityDate="2020-09-12T04:58:56.287" Title="Does US have more forest fires in Sep 2020 than average?" Tags="|wildfire|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20191" PostTypeId="2" ParentId="20171" CreationDate="2020-09-10T23:50:48.123" Score="2" Body="&lt;p&gt;During the day, the sunlight is kept out of your house by the roof (assuming you don't have a glass ceiling or windows on your roof). At night, the sun sets and the outside atmosphere is allowed to emit infrared radiation. If there are clouds out, they emit infrared radiation back down to the surface. The atmosphere, itself, also emits radiation back (greenhouse effect), so the surface doesn't get too cold.&lt;/p&gt;&#xA;&lt;p&gt;Now let's compare what happens at night in your house. Presumably, your roof and house absorbs a lot of radiation during the day. During the night, your house emits radiation, but more than outside, since it is hotter (&lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stefan-Boltzmann equation&lt;/a&gt;). Your roof/ceiling emits radiation both inside and outside the house. This keeps the radiation &amp;quot;trapped&amp;quot; inside the house.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-09-10T23:50:48.123" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20193" PostTypeId="1" CreationDate="2020-09-11T08:10:19.733" Score="2" ViewCount="165" Body="&lt;p&gt;Record fires are blazing in the west coast, huge even compared to California's notorious summers.&lt;/p&gt;&#xA;&lt;p&gt;Dead plants and debris are crucial to get a fire started. This debris could be collected, carbonized, and buried, say as &lt;a href=&quot;https://en.wikipedia.org/wiki/Terra_preta&quot; rel=&quot;nofollow noreferrer&quot;&gt;terra preta&lt;/a&gt;.  &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2649247/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Biochar burial&lt;/a&gt; has been considered as a way to mitigate climate change.&lt;/p&gt;&#xA;&lt;p&gt;Cleaning up thousands of square miles of brush would be a massive undertaking. But we would avoid the &lt;a href=&quot;https://www.kron4.com/news/bay-area/new-record-23-consecutive-spare-the-air-alerts-worry-bay-area-officials/&quot; rel=&quot;nofollow noreferrer&quot;&gt;pervasive and persistent loss of air quality&lt;/a&gt; on top of an &lt;a href=&quot;https://www.usnews.com/news/national-news/articles/2019-04-08/100-000-americans-die-from-air-pollution-study-finds&quot; rel=&quot;nofollow noreferrer&quot;&gt;already high health cost&lt;/a&gt; as well as &lt;a href=&quot;https://www.accuweather.com/en/weather-news/california-wildfires-will-cost-tens-of-billions-accuweather-estimates/612548#:%7E:text=AccuWeather%20now%20estimates%20the%20total,AccuWeather%20Founder%20and%20CEO%20Dr.&amp;amp;text=AccuWeather%20estimates%20the%20total%20damage,and%20%2485%20billion%20in%202017.&quot; rel=&quot;nofollow noreferrer&quot;&gt;tens to hundreds of billions of dollars&lt;/a&gt; from property damage, economic disruption i.e. evacuations, and other costs such as &lt;a href=&quot;https://www.statista.com/chart/19807/california-wildfire-emergency-fund-expenditure/&quot; rel=&quot;nofollow noreferrer&quot;&gt;fighting fires&lt;/a&gt;. Would the combined benefit to cost ratio be competitive compared to the &amp;quot;typical&amp;quot; climate, health, or economic program?&lt;/p&gt;&#xA;" OwnerUserId="8476" LastEditorUserId="8476" LastEditDate="2020-09-11T08:51:31.207" LastActivityDate="2023-05-30T01:04:55.573" Title="Forest fuel biochar burial" Tags="|climate-change|carbon-cycle|wildfire|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20194" PostTypeId="2" ParentId="20189" CreationDate="2020-09-11T10:19:02.730" Score="3" Body="&lt;p&gt;For now it seems to be average, at least compared to the last decade. The National Interagency Fire Center has &lt;a href=&quot;https://www.nifc.gov/fireInfo/nfn.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;a page&lt;/a&gt; with a year-to-date statistics table. You can see that so far, the values for 2020 are pretty similar (even slightly below) to the 10-year average, both in terms of number of fires and burned acres.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;2020        |   Fires: 41,599   |   Acres: 5,288,247&#xA;2010-2019   |   Fires: 44,177   |   Acres: 5,761,034&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Now if you go &lt;a href=&quot;https://www.nifc.gov/fireInfo/fireInfo_stats_totalFires.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;further back in time&lt;/a&gt;, there seems to be an upward trend. I did not compute the means, but just by looking at the numbers you can guess that there were less fires in the 80's and 90's, and about the same amount as today from the 2000's.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-09-11T10:19:02.730" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20195" PostTypeId="1" AcceptedAnswerId="20200" CreationDate="2020-09-11T08:59:09.870" Score="0" ViewCount="212" Body="&lt;p&gt;Climate is a high order nonlinear dynamic system and as such:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;is complex to study&lt;/li&gt;&#xA;&lt;li&gt;is not controllable via linear input as in &lt;code&gt;we pollute less -&amp;gt; temperature drops&lt;/code&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I have observed various sources claiming that &amp;quot;assuming greenhouse gasses continue accumulating there will be a point where even if humanity and it's industry magically disappears, global temperatures are going to continue rising significantly&amp;quot;. I accept that as a proven fact by now.&lt;/p&gt;&#xA;&lt;p&gt;The associated big question is &lt;strong&gt;When?&lt;/strong&gt;. Follow a couple of sources which claim &amp;quot;5 years ago&amp;quot; and a couple of sources saying &amp;quot;perhaps some day&amp;quot;.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.nature.com/articles/s43247-020-0001-2#Fig3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dynamic ice loss from the Greenland Ice Sheet driven by sustained glacier retreat&lt;/a&gt; (the journal is classified as &lt;a href=&quot;https://mediabiasfactcheck.com/nature/&quot; rel=&quot;nofollow noreferrer&quot;&gt;reliable&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.forbes.com/sites/scottsnowden/2020/08/14/greenlands-melting-ice-sheets/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Melting Of Greenland’s Ice Sheets Has Passed The Point Of No Return, Scientists Say&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.nasa.gov/feature/goddard/nasa-study-mass-gains-of-antarctic-ice-sheet-greater-than-losses&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA Study: Mass Gains of Antarctic Ice Sheet Greater than Losses&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.pnas.org/content/116/29/14414&quot; rel=&quot;nofollow noreferrer&quot;&gt;A 40-y record reveals gradual Antarctic sea ice increases followed by decreases at rates far exceeding the rates seen in the Arctic&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="21219" OwnerDisplayName="Vorac" LastEditorUserId="21219" LastEditDate="2020-11-21T13:46:35.523" LastActivityDate="2020-11-21T13:46:35.523" Title="Has irreversible global warming already begun?" Tags="|climate-change|" AnswerCount="1" CommentCount="6" ClosedDate="2020-09-13T17:38:36.243" ContentLicense="CC BY-SA 4.0" />
  <row Id="20198" PostTypeId="2" ParentId="20189" CreationDate="2020-09-12T04:58:56.287" Score="3" Body="&lt;p&gt;For now the destruction of the US Pacific wild fires is &lt;a href=&quot;https://earthscience.stackexchange.com/questions/20189/does-us-have-more-forest-fires-in-sep-2020-than-average&quot;&gt;well above average&lt;/a&gt;. As of 11 September 2020,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;the fires have &lt;a href=&quot;https://time.com/5886622/record-wildfires-california-climate-change/&quot; rel=&quot;nofollow noreferrer&quot;&gt;obliterated California’s record&lt;/a&gt; for the number of acres burned in a year. Six of the top 20 largest fires in state history have occurred in 2020, according to Cal Fire.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The reasons for the fires are,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Lightning initially triggered many of the fires, but it was unusual and extreme meteorological conditions that turned some of them into the worst conflagrations in the region in decades. Record-breaking air temperatures, periods of unusually dry air, and blasts of fierce winds—on top of serious drought in some areas—led fires to ravage forests and loft vast plumes of smoke to rarely seen heights.&lt;/p&gt;&#xA;&lt;p&gt;... a perfect storm of meteorological factors come together that encouraged extreme burning ...&lt;/p&gt;&#xA;&lt;p&gt;... on top of shifting climate patterns—a long term drying and warming of both the air and vegetation—that is contributing to the growing trend we are seeing toward larger, higher-intensity fires in the U.S. West.&lt;/p&gt;&#xA;&lt;p&gt;The buildup of fuels may be another relevant factor. Human efforts to extinguish most fires over the past 120 years has led to an increase in old, overgrown forests in the West that burn intensely when they catch fire.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-09-12T04:58:56.287" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20200" PostTypeId="2" ParentId="20195" CreationDate="2020-09-12T22:03:10.220" Score="1" Body="&lt;p&gt;Yes and no. From a pedantic point of view, the question is ill-posed: the concept of reversibility does not make sense in a chaotic system.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, it is an idea that is widely discussed, and most people have a rough idea of what is meant.&lt;/p&gt;&#xA;&lt;p&gt;There are three possible interpretations of the question that I can think of:&lt;/p&gt;&#xA;&lt;p&gt;(1) If the abundance of greenhouse gasses in the atmosphere is returned to pre-industrial levels in the next hundred years, has there been irreversible change which will stop the climate returning to its pre-industrial state at the same time, at least as far as the global mean temperature is concerned?&lt;/p&gt;&#xA;&lt;p&gt;Answer: no, at least not much. There will be differences because of changes in albedo arising from changes in vegetation and ice cover. Some of the changes in ice cover will be irreversible, at least on the time scale of millenia. This is because the Greenland ice-sheet was formed during the last ice age, and won't recover the mass it is loosing until the next ice age. There will also be a lag in the recovery of the Ocean temperature.&lt;/p&gt;&#xA;&lt;p&gt;(2) A second possible interpretation of the question is: if we stop burning fossil fuel, and start extracting CO2 from the atmosphere, will the warming trend continue?&lt;/p&gt;&#xA;&lt;p&gt;Answer: no, probably, if we do it soon enough, but it is possible. The difficulty here is removing enough CO2 to make a difference. If we leave it too late, there is a risk that natural feedbacks (e.g. increased frequency of forest fires, methane emission from permafrost) will release greenhouse gasses faster than we can remove them. I'm not aware of anybody making even a rough quantitative estimate of the risk of a run-away warming feedback, but the risk exists and grows as the temperature rises. If you are of a nervous disposition, events such as the raging fires in Australia last year look very ominous. When it comes to forest fires, however, it is, however, very difficult to disentangle impacts of rising temperature from changes in forest management, but there are a number of studies, e.g. &lt;a href=&quot;https://nhess.copernicus.org/preprints/nhess-2019-206/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://nhess.copernicus.org/preprints/nhess-2019-206/&lt;/a&gt;, linking climate change to an increase in fire activity.&lt;/p&gt;&#xA;&lt;p&gt;(3) If the question is about irreversible melting of ice, rather than irreversible temperature change, then the answer is most likely yes -- in many areas ice volume will not recover. There are changes to the surface albedo of Greenland which make it likely that it will continue melting. The Greenland ice sheet is a fossil ice sheet, meaning that it only exists because it was formed in the ice age: there is no mechanism to grow it back in the inter-glacial period.&lt;/p&gt;&#xA;" OwnerUserId="17518" LastActivityDate="2020-09-12T22:03:10.220" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20202" PostTypeId="2" ParentId="14187" CreationDate="2020-09-13T06:56:54.463" Score="0" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/noNa8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/noNa8.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;Almost 20 galactic years (each galactic year = 230 million solar years) have passed since birth of our sun, and three galactic years have passed since the remarkable formation of life on Earth when atmospheric oxygen concentration significantly increased (during the time period, we have orbited the Milky Way galaxy three times).&lt;/p&gt;&#xA;&lt;p&gt;Depending on the concentration of oxygen in the atmosphere and changes in life on Earth, each galactic year can be divided into almost regular &amp;quot;three seasons&amp;quot; each year, with oxygen increasing at different slopes in the first and second seasons and decreasing in the third.&lt;/p&gt;&#xA;&lt;p&gt;As the Sun orbits the Milky Way, it enters and exits the galactic arms at some specific times, which may be the &amp;quot;probable&amp;quot; cause of these near-regular events of massive extinctions and changes in the concentration of atmospheric gases on Earth in each galactic year, due to significant increase in flux of incoming cosmic rays.&lt;/p&gt;&#xA;&lt;p&gt;There are some main arms of milky way galaxy that sun goes through as travels around the center of the galaxy. When earth enters a galaxy arm, the constant heavy rain of cosmic rays (high-powered) hit our planet's atmosphere at nearly the speed of light. The very high energy cosmic rays break the strands of DNA molecules, damage genes and kill cells (resulting in cell mutations, death and extinction).&lt;/p&gt;&#xA;&lt;p&gt;The cosmic rays also shatter air molecules high in our atmosphere, collide with atoms and molecules (mainly oxygen and nitrogen) or even split the molecules, and send atomic and subatomic particles showering down on Earth, so-called air shower secondary radiation.&lt;/p&gt;&#xA;&lt;p&gt;The incoming cosmic rays by colliding with nitrogen molecules, the process replaces one of the 7 protons nitrogen contains with an extra neutron. The resulting atom, now containing 6 protons and 8 neutrons, is one of carbon 14. As result, nitrogen in the atmosphere changes to Carbon-14 by cosmic rays.The generated Carbon-14 (radioactive) then reacts with oxygen in the atmosphere and forms CO2 (as result of this process also, concentration of oxygen is reduced). The CO2 from Carbon-14 is then absorbed by the plants.&lt;/p&gt;&#xA;&lt;p&gt;In addition, earth temperature may have also rised by increased flux of incoming cosmic rays, increasing water evaporation from oceans into atmosphere (air) that results in higher number of water molecules being spilt by the cosmic rays.&lt;/p&gt;&#xA;&lt;p&gt;All these events changed the atmospheric gases concentration and life conditions on earth during traveling of sun into each arm of the galaxy.&lt;/p&gt;&#xA;&lt;p&gt;However, future research will provide a more accurate answer to this question.&lt;/p&gt;&#xA;&lt;p&gt;More information can be found here:&#xA;1- &lt;a href=&quot;https://www.researchgate.net/publication/256762257_Mass_Extinction_And_The_Structure_Of_The_Milky_Way&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/publication/256762257_Mass_Extinction_And_The_Structure_Of_The_Milky_Way&lt;/a&gt;&#xA;2- &lt;a href=&quot;https://www.space.com/19915-milky-way-galaxy.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.space.com/19915-milky-way-galaxy.html&lt;/a&gt;&#xA;3- &lt;a href=&quot;https://www.radioactivity.eu.com/site/pages/RadioCarbon.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.radioactivity.eu.com/site/pages/RadioCarbon.htm&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21075" LastEditorUserId="21075" LastEditDate="2020-09-13T13:21:10.477" LastActivityDate="2020-09-13T13:21:10.477" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20203" PostTypeId="2" ParentId="13217" CreationDate="2020-09-14T13:49:15.130" Score="1" Body="&lt;p&gt;A Graben/Rift valley is more attuned to divergent plate environment where as a Trench is mostly used and accepted when convergent plate activities is under discussion, other wise the two portray the same geological features/meaning.&lt;/p&gt;&#xA;&lt;p&gt;The German term for a graben is Graben (literally &amp;quot;trench&amp;quot;).&lt;/p&gt;&#xA;" OwnerUserId="21080" LastEditorUserId="23261" LastEditDate="2021-08-14T00:31:58.540" LastActivityDate="2021-08-14T00:31:58.540" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20204" PostTypeId="1" CreationDate="2020-09-14T15:09:50.030" Score="1" ViewCount="22" Body="&lt;p&gt;On 8th September 2020 there was a &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/eventpage/us7000bjlf/region-info&quot; rel=&quot;nofollow noreferrer&quot;&gt;magnitude 3.9 earthquake here in the UK&lt;/a&gt; at &lt;a href=&quot;https://www.google.com/maps/place/51%C2%B049%2701.2%22N+0%C2%B039%2754.0%22W/@51.817,-0.7350432,12z/data=!4m5!3m4!1s0x0:0x0!8m2!3d51.817!4d-0.665&quot; rel=&quot;nofollow noreferrer&quot;&gt;51.817°N 0.665°W&lt;/a&gt; which is approx. 10km/6.2miles east of Aylesbury or roughly 50km/31miles east of Oxford.&lt;/p&gt;&#xA;&lt;p&gt;This got me wondering how the epicentre could be right there when there are no tectonic plate edges there.  The UK sits within the Eurasian Tectonic Plate, not on the edge.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4gnlh.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4gnlh.png&quot; alt=&quot;The Eurasian Tectonic Plate&quot; /&gt;&lt;/a&gt;&#xA;&lt;sub&gt;Image courtesy of &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:EurasianPlate.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;WikiMedia Commons&lt;/a&gt; and under creative commons licence &lt;a href=&quot;https://creativecommons.org/licenses/by-sa/4.0/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CC BY-SA 4.0&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;So how could an earthquake occur in the UK and what kind of earthquake would it be? The depth of this quake was at &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/eventpage/us7000bjlf/origin/detail&quot; rel=&quot;nofollow noreferrer&quot;&gt;10km ± 2km&lt;/a&gt; so was it a &lt;a href=&quot;https://en.wikipedia.org/wiki/Subduction&quot; rel=&quot;nofollow noreferrer&quot;&gt;subduction quake&lt;/a&gt;? If so the subduction plate boundary would be huge.&lt;/p&gt;&#xA;" OwnerUserId="21081" LastEditorUserId="21081" LastEditDate="2020-09-14T15:19:50.020" LastActivityDate="2020-09-14T15:19:50.020" Title="Seismic activity in the UK" Tags="|plate-tectonics|earthquakes|" AnswerCount="0" CommentCount="1" ClosedDate="2020-09-14T19:06:26.307" ContentLicense="CC BY-SA 4.0" />
  <row Id="20205" PostTypeId="1" AcceptedAnswerId="20208" CreationDate="2020-09-14T15:14:19.840" Score="4" ViewCount="984" Body="&lt;p&gt;Tsunamis can be caused by underwater earthquakes, like the 2004 tsunami in the Indian Ocean. The precise value will likely depend on where the earthquake is relative to the coast. But what is the time range between the moment the earthquake is detected and the moment a tsunami hits the coast? Is it minutes? Hours?&lt;/p&gt;&#xA;" OwnerUserId="18434" LastActivityDate="2020-09-16T21:37:05.620" Title="How much time is there between an underwater earthquake and the moment a tsunami hits the coast?" Tags="|earthquakes|tsunami|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20206" PostTypeId="1" CreationDate="2020-09-14T17:09:30.133" Score="1" ViewCount="145" Body="&lt;p&gt;I creat wrfchemi file for my wrf-chem, my wrfchemi file has 30 time step,&#xA;&lt;strong&gt;frames_per_auxinput5&lt;/strong&gt;     = &lt;strong&gt;30,   30,&lt;/strong&gt;&#xA;auxinput5_inname         = &amp;quot;wrfchemi_d&lt;em&gt;&amp;quot;,&#xA;auxinput5_interval_m     = &lt;strong&gt;60,  60,&lt;/strong&gt;&#xA;&lt;strong&gt;frames_per_auxinput7&lt;/strong&gt;     = &lt;strong&gt;30,    30,&lt;/strong&gt;&#xA;io_form_auxinput5        = 2,&#xA;auxinput7_inname         = &amp;quot;wrffirechemi_d&lt;/em&gt;&amp;quot;,&#xA;auxinput7_interval_m     = &lt;strong&gt;60,  60,&lt;/strong&gt;&#xA;io_form_auxinput7       = 2,&lt;/p&gt;&#xA;&lt;p&gt;when I run ./wrf.exe, I face with this error:&lt;/p&gt;&#xA;&lt;p&gt;3  input_wrf: wrf_get_next_time current_date: 2010-07-16_18:00:00 Status =          -11&#xA;At line 1008 of file input_wrf.f90&#xA;Fortran runtime error: End of record&#xA;my name list.input:&#xA;&lt;a href=&quot;https://drive.google.com/file/d/18vePBFOk-zrq761ex1siJ7KDF1x8CGif/view?usp=sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://drive.google.com/file/d/18vePBFOk-zrq761ex1siJ7KDF1x8CGif/view?usp=sharing&lt;/a&gt;&#xA;my rsl.error:&#xA;&lt;a href=&quot;https://drive.google.com/file/d/129FuD4f7g8FIRhVykfrRm5BY-dDrDEWo/view?usp=sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://drive.google.com/file/d/129FuD4f7g8FIRhVykfrRm5BY-dDrDEWo/view?usp=sharing&lt;/a&gt;&#xA;my wrfchemifile:&#xA;&lt;a href=&quot;https://drive.google.com/file/d/1dDJ8JheDhyRnBHDOX5Xzqg5vb2quVO3F/view?usp=sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://drive.google.com/file/d/1dDJ8JheDhyRnBHDOX5Xzqg5vb2quVO3F/view?usp=sharing&lt;/a&gt;&#xA;could you please help me to sole this error and run the mode?&#xA;thank you very much in deed&lt;/p&gt;&#xA;" OwnerUserId="18881" LastActivityDate="2020-09-14T17:09:30.133" Title="wrf_chemi file with 30 time steps" Tags="|meteorology|atmosphere-modelling|numerical-modelling|wrf|wrf-chem|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="20207" PostTypeId="2" ParentId="14654" CreationDate="2020-09-14T19:44:23.897" Score="4" Body="&lt;p&gt;Chances are you do not have presences of fuel in your water. This sounds like you could have a few different things happening.&lt;/p&gt;&#xA;&lt;p&gt;First off, iron reducing bacteria can lead to significant corrosion. These are bacteria that feed on iron both in the water and also in plumbing systems. They also can put off a smell.&lt;/p&gt;&#xA;&lt;p&gt;The second one is manganese. If you notice this smell after rain, etc. then this is a possibility. Manganese can make the water blackish and smell like fuel oil. While mostly harmless, it can cause issues with staining, etc.&lt;/p&gt;&#xA;&lt;p&gt;If you have a private well and live in a hard water area, both of these could be occurring simultaneously. Correlation is not always causation. What the smell is vs. what is causing the corrosion could be separate issues.&lt;/p&gt;&#xA;&lt;p&gt;Lastly, if the pH is off in the water, too acidic or too base then this can also eat away at your pipes. Typically though, many water quality smell and plumbing issues come from bacterial issues. Check this first and then move on if negative.&lt;/p&gt;&#xA;" OwnerUserId="21082" LastActivityDate="2020-09-14T19:44:23.897" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20208" PostTypeId="2" ParentId="20205" CreationDate="2020-09-15T00:35:57.473" Score="5" Body="&lt;p&gt;As a general guideline, the time between the actual earthquake and the time the tsunami arrives is on the order of minutes to hours.&lt;/p&gt;&#xA;&lt;p&gt;Tsunamis out in the deep ocean travel very fast -- around 500 mph -- which means that they cross ocean basins in about as much time as it takes a plane to fly across. So an earthquake in Japan gives Hawaii and the US West Coast many many hours of warning.&lt;/p&gt;&#xA;&lt;p&gt;Close to shore, tsunamis are much slower, but of course the distances are also shorter. For a place where earthquakes happen close to shore because of a subduction zone, say in Japan, this only gives you a few or a few tens or minutes of advance warning. If you take the 2011 tsunami in Japan, warnings were sounded quite quickly, and that allowed a large number of people to get to higher ground and will have saved tens of thousands of lives. But at the same time, it was not enough time to actually go door to door, put people onto buses, and get them out of harm's way if either they did not hear the warning, or refused for whatever reason to immediately evacuate.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastEditorUserId="5259" LastEditDate="2020-09-16T21:37:05.620" LastActivityDate="2020-09-16T21:37:05.620" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20209" PostTypeId="2" ParentId="42" CreationDate="2020-09-15T17:32:30.923" Score="1" Body="&lt;p&gt;Monsoons are caused by ITCZ changing between the months. This means that because the earth tilts 23.5 degrees north each year, maximum solar insolation varies, causing low pressure to gather. Hence the monsoons.&lt;a href=&quot;https://i.stack.imgur.com/pgK1I.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pgK1I.png&quot; alt=&quot;ITCZ at northern and southern hemisphere summers.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21089" LastEditorUserId="21089" LastEditDate="2020-09-15T18:13:25.363" LastActivityDate="2020-09-15T18:13:25.363" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20213" PostTypeId="1" CreationDate="2020-09-17T09:43:06.697" Score="1" ViewCount="36" Body="&lt;p&gt;Some basic differences are needed for children to understand only. The language should be simple enough so that any age understands for 5 to 99 or maybe 100.&lt;/p&gt;&#xA;" OwnerUserId="21099" LastActivityDate="2020-09-17T09:43:06.697" Title="difference between climatology and meteorology only" Tags="|meteorology|climatology|" AnswerCount="0" CommentCount="4" ClosedDate="2020-09-20T16:23:15.910" ContentLicense="CC BY-SA 4.0" />
  <row Id="20215" PostTypeId="2" ParentId="10746" CreationDate="2020-09-17T14:45:39.817" Score="0" Body="&lt;p&gt;I'd like to add something to the (otherwise nice) &lt;a href=&quot;https://earthscience.stackexchange.com/a/10748/18081&quot;&gt;answer&lt;/a&gt; of @BarocliniCplusplus. Although climatology used to be focused solely on the atmosphere, now it integrates other components of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_system&quot; rel=&quot;nofollow noreferrer&quot;&gt;climate system&lt;/a&gt;, such as the oceans, the vegetation, and even the crust. In that sense, one could say that &amp;quot;atmospheric science&amp;quot; focuses on one aspect of climatology (probably the main one, to be honest), but that &amp;quot;climatology&amp;quot; is not restricted to the atmosphere: you can be a climatologist and study ocean circulation.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-09-17T14:45:39.817" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20216" PostTypeId="1" AcceptedAnswerId="20220" CreationDate="2020-09-17T19:49:52.857" Score="3" ViewCount="69" Body="&lt;p&gt;I need an administrative division map of england for a motivation for some scientific workshop. I don't want to cite wikipedia for this. Sadly I can't find any official resources and I don't really know what sites are generally trusted or scientific.&lt;/p&gt;&#xA;&lt;p&gt;Any tips? I hope this is the correct forum for this answer.&lt;/p&gt;&#xA;" OwnerUserId="21104" LastActivityDate="2020-09-18T07:56:29.783" Title="Resource for scientific maps?" Tags="|geography|mapping|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20217" PostTypeId="2" ParentId="20175" CreationDate="2020-09-17T20:52:50.973" Score="1" Body="&lt;p&gt;Frost leaves a record by damaging the cell structure, creating a &amp;quot;frost ring&amp;quot;. &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S2212094719301811&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hadd et al&lt;/a&gt; discuss data on frost rings in N. American trees.&lt;/p&gt;&#xA;&lt;p&gt;There is specific discussion of the Fimbul event (in AD 536) in this paper by &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0277379118308357&quot; rel=&quot;nofollow noreferrer&quot;&gt;Helama et al. 2019&lt;/a&gt; (unfortunately with a pay wall). There is also discussion that there may have been a similar event in 1627 BC.&lt;/p&gt;&#xA;&lt;p&gt;If the data is good enough, it may be possible to get an estimate of the time of year at which the damage occurred by looking at the structure of the damaged cells and seeing how it fits with what is known about the annual cycle of cell growth. This requires more detailed analysis than the widely used approach of measuring ring thickness to estimate annual mean (or growing season mean) temperature.&lt;/p&gt;&#xA;&lt;p&gt;There is more recent information on ultra-cold summers in the Northern hemisphere, the &amp;quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Year_Without_a_Summer&quot; rel=&quot;nofollow noreferrer&quot;&gt;year without winter&lt;/a&gt;&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="17518" LastEditorUserId="17518" LastEditDate="2020-09-18T07:51:18.550" LastActivityDate="2020-09-18T07:51:18.550" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20219" PostTypeId="2" ParentId="20216" CreationDate="2020-09-18T04:08:49.313" Score="3" Body="&lt;p&gt;Most maps of Great Britain derive from the maps published by &lt;a href=&quot;https://en.wikipedia.org/wiki/Ordnance_Survey&quot; rel=&quot;nofollow noreferrer&quot;&gt;Her Majesty's Ordnance Survey&lt;/a&gt;.  The official website is &lt;a href=&quot;https://www.ordnancesurvey.co.uk/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ordnancesurvey.co.uk/&lt;/a&gt; and the &lt;a href=&quot;https://shop.ordnancesurvey.co.uk/apps/os-maps/&quot; rel=&quot;nofollow noreferrer&quot;&gt;sales page&lt;/a&gt; says that for £23.99 you can get a 1 year subscription to a digital app that gives you the ability to export in the &lt;a href=&quot;https://en.wikipedia.org/wiki/GPS_Exchange_Format&quot; rel=&quot;nofollow noreferrer&quot;&gt;GPX&lt;/a&gt; digital format.&lt;/p&gt;&#xA;&lt;p&gt;A crowd sourced version working on a map of the world is &lt;a href=&quot;https://www.openstreetmap.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Open Street Map&lt;/a&gt; Project.  This is equivalent to your rejected option of Wikipedia but I mention it for others that may land on this question.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastEditorUserId="8513" LastEditDate="2020-09-18T04:17:31.407" LastActivityDate="2020-09-18T04:17:31.407" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20220" PostTypeId="2" ParentId="20216" CreationDate="2020-09-18T07:56:29.783" Score="3" Body="&lt;p&gt;I usually refer to two free of charge sources for administrative division maps:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;for Europe, as in your case (I hope they still hold the maps of UK even after Brexit...) you can use the official NUTS - Nomenclature of territorial units for statistics maps from EUROSTAT available &lt;a href=&quot;https://ec.europa.eu/eurostat/web/nuts/nuts-maps&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;;&lt;/li&gt;&#xA;&lt;li&gt;EUROSTAT has also a regularly updated dataset of the official boundaries for the whole world &lt;a href=&quot;https://ec.europa.eu/eurostat/web/gisco/geodata/reference-data/administrative-units-statistical-units/countries&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; (latest update 2020, but I don't remember how down to the finer statistical territorial units they get with this);&lt;/li&gt;&#xA;&lt;li&gt;DIVA GIS repository: administrative maps of every country in the world (not sure how updated this is), available &lt;a href=&quot;https://www.diva-gis.org/gdata&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I'm sure there will be more datasets like these, but these should fit your purposes.&lt;/p&gt;&#xA;" OwnerUserId="8087" LastActivityDate="2020-09-18T07:56:29.783" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20221" PostTypeId="1" AcceptedAnswerId="20223" CreationDate="2020-09-18T15:44:18.647" Score="1" ViewCount="302" Body="&lt;p&gt;I've seen some videos of people scooping up some water from a natural body of it, adding some sand and a few plants, and soon enough, they have a (near) self-sustaining aquarium. I've always wanted to do this, but I'm not exactly sure how. There's a river in a small ravine (about 20 ft. deep) behind my house, and a nearby pond, so I think I might be able to manage this, but before I do, is there anything I need to know, or any suggestions on how to pull this off? Thanks in advance!&lt;/p&gt;&#xA;&lt;p&gt;P.S. I don't want to take any animals (such as frogs), and trap them is a confined space. All I really want is some organisms that are just large enough to see, and I think I'd be good. If I do take anything from the wild, though, I want to return it, and I want to make it a pretty darn good habitat, so it doesn't feel trapped.&lt;/p&gt;&#xA;" OwnerUserId="20714" LastActivityDate="2020-09-25T03:56:24.643" Title="Self-sustaining aquarium in a jar?" Tags="|water|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20222" PostTypeId="1" CreationDate="2020-09-18T17:17:15.380" Score="4" ViewCount="63" Body="&lt;p&gt;In the 2005 Atlantic Hurricane Season, we got all the way to Tropical Storm Zeta, which is the current record. This year we may very well surpass that. However, right after Zeta come Eta and then Theta. This means that potentially there could be three concurrent storms all having rhyming names. Due to the possible public confusion, is it likely the WMO will revisit the convention of using the Greek alphabet in order as an auxiliary list?&lt;/p&gt;&#xA;" OwnerUserId="21105" LastActivityDate="2020-09-18T17:17:15.380" Title="In the future, is the World Meteorological Organization going to allow Hurricanes Zeta, Eta, and Theta to exist simultaneously?" Tags="|meteorology|tropical-cyclone|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20223" PostTypeId="2" ParentId="20221" CreationDate="2020-09-18T19:39:25.270" Score="1" Body="&lt;p&gt;It is called an aquarium, put what ever you want in it. With natural waters you have a good chance of collecting dragonfly larva , which will eat about anything else you catch including small fish. Chances of mosquito larva are low in my experience. I don't know why you would not want frog or toad tadpoles ; I have a couple very small feral ponds in my yard and various frogs and toads  deposit uncountable numbers of eggs &amp;gt; tadpoles. Some years I have taken thousands of tadpoles to nearby lakes and dumped them . When I don't do that most get eaten by siblings. You are unlikely to find suitable native plants other than duckweed, so I suggest buying Hornwort at a pet shop -pretty bullet proof.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2020-09-18T19:39:25.270" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20224" PostTypeId="1" CreationDate="2020-09-19T10:44:33.220" Score="3" ViewCount="154" Body="&lt;p&gt;The traditional list of hurricane names for the year goes from A to W, and, in the very rare occurrence that the W storm has formed and there is another tropical storm out there, then the Greek letter names (Alpha, Beta, Gamma, etc. to Omega) are used (e.g., &lt;a href=&quot;https://en.wikipedia.org/wiki/2005_Atlantic_hurricane_season&quot; rel=&quot;nofollow noreferrer&quot;&gt;2005 Atlantic hurricane season&lt;/a&gt;). Considering the activity so far (September 2020) of the &lt;a href=&quot;https://en.wikipedia.org/wiki/2020_Atlantic_hurricane_season&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atlantic hurricane season&lt;/a&gt;, and that we still have two months of season (i.e., &lt;a href=&quot;https://earthscience.stackexchange.com/questions/811/why-is-the-atlantic-hurricane-season-defined-as-being-between-june-1-and-novembe&quot;&gt;until November 30&lt;/a&gt;), what is the next naming list coming from (if there even is one)?&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2020-09-19T10:44:33.220" Title="What will happen if the Greek letter names were exhausted for naming tropical storms?" Tags="|meteorology|tropical-cyclone|storms|atlantic|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="20225" PostTypeId="1" CreationDate="2020-09-20T02:24:34.000" Score="1" ViewCount="89" Body="&lt;p&gt;Take a look at this picture.&lt;a href=&quot;https://i.stack.imgur.com/nwCvh.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nwCvh.png&quot; alt=&quot;Mesocyclone beginning&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Moist updrafts interact with highly-sheared upper-level winds, which sets up a horizontal vortex. But &lt;em&gt;why?&lt;/em&gt; What causes the air to be forced downward and to the right, then continue rising (also to the right)?&lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2020-09-20T02:24:34.000" Title="In a mesocyclone, why does wind shear create a horizontal axis of spinning air?" Tags="|meteorology|severe-weather|mesoscale-meteorology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20226" PostTypeId="1" AcceptedAnswerId="20299" CreationDate="2020-09-20T02:33:51.303" Score="2" ViewCount="172" Body="&lt;p&gt;Take something like the Bermuda High, for instance. I drew a crude illustration of it. &lt;a href=&quot;https://i.stack.imgur.com/7ly1y.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7ly1y.png&quot; alt=&quot;crude illustration&quot; /&gt;&lt;/a&gt;It steers hot, humid air from the Gulf of Mexico towards the east coast of North America. But upper level winds are far away from the surface winds/mid-level winds, so how do they manage to influence them?&lt;/p&gt;&#xA;&lt;p&gt;Same with a midlatitude cyclone. On the lower left quadrant (at least in the Northern Hemisphere), it will steer cold, dry northwesterlies at the surface. The end result can range from sunny, low-humidity conditions (such as after a tornado outbreak in the Mid-South) to bitter cold. How is this possible?&lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2020-10-08T08:57:20.583" Title="How do upper-level cyclones and anticyclones affect surface level winds?" Tags="|meteorology|mesoscale-meteorology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20227" PostTypeId="1" CreationDate="2020-09-20T10:27:38.297" Score="1" ViewCount="75" Body="&lt;p&gt;Why are there no giant nickel porphyry deposits like those of copper, or SEDEX deposits, like those of zinc? Why is all the nickel found in direct magmatic intrusions from the mantle to the surface? Why isn't more nickel found from epithermal deposits in which water runs down to a deep seated magmatic intrusion, picks up the metals, and deposits them on the surface?&#xA;Also, as I understand it, the copper found in the Andean deposits are from water going down and picking up metal from the melting continental crust sitting above the subducting oceanic crust. It's not coming from any mantle rocks. Is that correct, and if so, why don't we get nickel deposits in the Andes too?&lt;/p&gt;&#xA;" OwnerUserId="21109" LastActivityDate="2020-09-20T10:27:38.297" Title="Nickel question - non geologist me" Tags="|plate-tectonics|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="20229" PostTypeId="2" ParentId="19523" CreationDate="2020-09-20T22:38:47.410" Score="3" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Are there any other measurements that have contributed to current understanding of Earth's core besides these two?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The answer is of course &amp;quot;yes&amp;quot;. Other answers have already alluded to laboratory experiments that attempt to re-create conditions similar to those well inside the Earth.&lt;/p&gt;&#xA;&lt;p&gt;I'll provide two others; there are many more.&lt;/p&gt;&#xA;&lt;p&gt;One is radio astronomy. Determining the apparent locations of quasars has drastically increased the accuracy of the Earth's orientation. Doing this in conjunction with modern communication techniques results in Very Long Baseline Interferometry. The combination of the two has reduced the uncertainties in the Earth's orientation to well under a milliarcsecond. This gives deep insight (pun intended) into the nature of the Earth's core. The Earth's Chandler wobble does not behave quite like that of a rigid body. How this varies over time gives insights into the nature of the Earth's core. The Earth's &lt;a href=&quot;https://www.aanda.org/articles/aa/pdf/2013/07/aa21585-13.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;free core nutation&lt;/a&gt; is also observable from the precise Earth orientation parameters.&lt;/p&gt;&#xA;&lt;p&gt;Another is precise gravity models of the Earth. These too give insights into the Earth's core, including the Earth's moment of inertia, the Chandler wobble, and the free core nutation. Going beyond the Earth, gravity models provide one of the key observational techniques for studying the interior of the Moon, Mars, and Jupiter. Scientists know that the &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0019103516300720&quot; rel=&quot;nofollow noreferrer&quot;&gt;Moon&lt;/a&gt; and &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0032063309000178&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mars&lt;/a&gt; have partially molten cores thanks to gravity models developed from precise orbit determination based on the many satellites that have orbited the Moon and Mars. Scientists know that &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017GL073160&quot; rel=&quot;nofollow noreferrer&quot;&gt;Jupiter has a diffuse core&lt;/a&gt; thanks to precise orbit determination of the Juno spacecraft's orbit about the planet.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2020-09-20T23:23:07.020" LastActivityDate="2020-09-20T23:23:07.020" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20230" PostTypeId="1" CreationDate="2020-09-21T00:45:53.360" Score="1" ViewCount="2179" Body="&lt;p&gt;I have some set of recorded data in dip direction/dip format. I wish to transform then to strike/dip.&lt;/p&gt;&#xA;&lt;p&gt;I am currently having a hard time imagining how to convert from dip direction to strike direction. However, it is easier for me to convert from strike direction to dip direction. I am currently using the right hand rule (British), but it seems not to be working well for me. Generally, I have used the index finger as my dip direction and thumb finger as the strike direction.&lt;/p&gt;&#xA;&lt;p&gt;For example, if I have my strike and dip written as 183/54W, I can conveniently transform this to dip direction and dip using the right hand rule. My thumb will point towards 183 degrees, and then I will position my index to be towards the west of it, this way I can measure the azimuth and record the dip direction to be 273.  So, this will be written as 273/54. The nice thing here is that I can transform 273/54 back to 183/54W, by simply putting my index finger back to 273, and my thumb will be 90 degrees away from it, thereby, making it 183.&lt;/p&gt;&#xA;&lt;p&gt;In the second case, I have a data reading 126/33NE in the strike dip format. I have transformed this to dip direction and dip format by putting my thumb finger towards 126 degrees, and by making my index finger to be towards E (This was in an awkward way, because I had to place my index over my thumb in a 90 degree manner). In this way, I will subtract 90 from 126, and get 36 degrees. This will then be written as 036/33. However, if I do try to revert from 036/33, assuming that I had no prior knowledge of the original 126/33NE and using the right hand rule appropriately, I will have my thumb pointing toward 306 degrees. Then, the result will be written as 306/33NE. There has been a 180 degree shift in the recorded value.&lt;/p&gt;&#xA;&lt;p&gt;What could I be doing wrong? If there a better way to make this conversion? Thanks a lot in advance for your response.&lt;/p&gt;&#xA;" OwnerUserId="21113" LastEditorUserId="2470" LastEditDate="2020-09-21T03:22:55.720" LastActivityDate="2020-09-21T03:22:55.720" Title="Is there a way to convert from Dip direction to Strike direction?" Tags="|geology|geophysics|structural-geology|coordinate-system|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20231" PostTypeId="1" AcceptedAnswerId="20232" CreationDate="2020-09-19T14:15:02.113" Score="4" ViewCount="969" Body="&lt;p&gt;&lt;strong&gt;How do scientists confirm iron core at the centre of the earth?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;We know scientists couldn’t yet drill to the core of our planet earth. Yet we know they confirmed there is a core of iron at the centre of it. How did they confirm that? Is it yet in hypothetical state or it’s already confirmed? What are the test approaches we know?&lt;/p&gt;&#xA;" OwnerDisplayName="Sazzad Hissain Khan" LastActivityDate="2020-09-21T12:08:50.830" Title="How do scientists confirm iron core at the centre of the earth?" Tags="|core|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20232" PostTypeId="2" ParentId="20231" CreationDate="2020-09-19T16:18:28.143" Score="8" Body="&lt;p&gt;This is more a geophysics than an astronomy question—and thus the available methods of investigation are greatly increased. An Earth model also is not a one-person-show based on one measurement, but requires many different measurements from different fields with greatly different methods which form a unique picture which leaves only few possibile explanations which fit all observations.&lt;/p&gt;&#xA;&lt;p&gt;One of the easiest methods to investigate the interior of the Earth is seismic sounding. Investigations of the deep interior of the Earth use teleseismic, which means we scan the seismic velocity of Earth by using the seismic waves generated by an Earthquake. The time-of-arrival of the different direct but also reflected waves at the different seismometers all over the world—or the absence of any arrival at all—allows to get a &lt;a href=&quot;https://www.geophysik.uni-muenchen.de/%7Eigel/Lectures/Sedi/sedi_inter.pdf&quot; rel=&quot;noreferrer&quot;&gt;quite detailed mapping&lt;/a&gt; of the interior structure in terms of seismic velocities as function of depth and also whether the material is liquid or not. This already gives you the principle structure of Earth with a mantle with many of its different layers and the existence of an outer, liquid core and an inner solid core, e.g. see the 40 year old &lt;a href=&quot;http://ds.iris.edu/spud/earthmodel/9991844&quot; rel=&quot;noreferrer&quot;&gt;preliminary Earth reference model&lt;/a&gt;. See also the &lt;a href=&quot;https://earthscience.stackexchange.com/questions/19550/how-do-we-know-the-speed-of-s-waves-shear-waves-in-the-earths-inner-core-has&quot;&gt;outstanding answer&lt;/a&gt; to this question about seismics and the &lt;a href=&quot;https://www.youtube.com/watch?v=j7eoxizmC1I&quot; rel=&quot;noreferrer&quot;&gt;video&lt;/a&gt; by the answerer or a &lt;a href=&quot;https://www.youtube.com/watch?v=vZ80K3i4t3w&quot; rel=&quot;noreferrer&quot;&gt;newerver version of it&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Measuring density is much more complicated and needs a detailed analysis of Earth's rotation, deriving the moments of inertia to as many degrees as you can get. However from that you get a good indication that the center has to be much denser than the crust and mantle. There's a lot of work on that, as a random paper the one by &lt;a href=&quot;https://academic.oup.com/gji/article/132/2/374/673083&quot; rel=&quot;noreferrer&quot;&gt;Kennet (1998)&lt;/a&gt; might give some overview.&lt;/p&gt;&#xA;&lt;p&gt;This paragraph is now extremely abridged, yet still: With knowledge about density and seismic velocity you already have a very good handle and constraint on the mineralogy or chemistry. Especially with some knowledge about equations-of-state of the materials the choice becomes very limited. In laboratory setups you can create high-pressure and high-temperature configurations and measure the properties of the materials—including their seismic velocity, be that directly or indirectly via their Young modulus and poisson number etc (some links in &lt;a href=&quot;https://earthscience.stackexchange.com/questions/19523/do-we-know-anything-about-the-nature-of-earths-core-that-hasnt-come-from-magne&quot;&gt;this answer by user20217 to a similar question&lt;/a&gt;). Assuming that the whole solar system formed from one primordal cloud, the chemistry should be pretty uniform—and that also means that iron is missing in the materials on the Crust and mantle—and iron incidentially fits magnetic observations (we have a magnetic field!) and the requirement for a heavy core very nicely. It also is logical as heavy elements tend to sediment towards the centre in a differentiated body.&lt;/p&gt;&#xA;&lt;p&gt;As such to answer your question: it's not a hypothesis, it's a well-established theory backed by a multitude of greatly different observations which require the existence of a a liquid outer core and a solid inner core, which both consist of a iron with some nickel and traces of other heavy elements mixed into it.&lt;/p&gt;&#xA;" OwnerUserId="18918" OwnerDisplayName="planetmaker" LastActivityDate="2020-09-20T06:29:45.307" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20233" PostTypeId="1" AcceptedAnswerId="20235" CreationDate="2020-09-21T18:27:16.760" Score="1" ViewCount="782" Body="&lt;p&gt;I am exploring FLUXNET sites for actual evapotranspiration (ETP) data (I convert the energy balance closure-corrected latent heat to ETP).&lt;/p&gt;&#xA;&lt;p&gt;I am interested in the half-hourly data. During the night we see negative values. I would like to know the reason or physical process behind this.&lt;/p&gt;&#xA;&lt;p&gt;Can physically-based hydrological models handle this situation? (: estimating negative half-hourly ETPs)&lt;/p&gt;&#xA;&lt;p&gt;There are some discussion in web about how to handle the negative values of potential ETP, but not easy to find a solid discussion about the actual ETP in this case.&lt;/p&gt;&#xA;" OwnerUserId="20807" LastActivityDate="2021-01-28T09:22:58.937" Title="How to interpret the negative (actual) evapotranspiration values?" Tags="|meteorology|hydrology|evaporation|water-vapour|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20234" PostTypeId="1" CreationDate="2020-09-21T20:49:07.997" Score="1" ViewCount="46" Body="&lt;p&gt;I have been fascinated by photos of these for a while, and I would like to ask how megaspherulites grow so large, when spherulites are normally quite small?&lt;/p&gt;&#xA;&lt;p&gt;I also noticed that all papers about the formation of megaspherulites I could find (such as &lt;a href=&quot;https://www.researchgate.net/publication/23822404_Growth_of_Megaspherulites_In_a_Rhyolitic_Vitrophyre&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; one) seem to say that they form in rhyolitic vitrophyre.&lt;/p&gt;&#xA;&lt;p&gt;Why do they only form in rhyolitic vitrophyre?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Yiaxb.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Yiaxb.jpg&quot; alt=&quot;megaspherulite photo&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21102" LastEditorUserId="21102" LastEditDate="2020-09-22T00:12:47.910" LastActivityDate="2020-09-22T00:12:47.910" Title="Megaspherulite growth" Tags="|geology|rocks|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20235" PostTypeId="2" ParentId="20233" CreationDate="2020-09-22T07:21:02.357" Score="5" Body="&lt;p&gt;Negative values for the ET, both potential and actual, usually refer to &lt;a href=&quot;https://en.wikipedia.org/wiki/Condensation&quot; rel=&quot;noreferrer&quot;&gt;condensation&lt;/a&gt;.&#xA;See also &amp;quot;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/17839/era5-mean-evaporation-rates-data-why-is-that-negative/17854#17854&quot;&gt;ERA5 mean evaporation rates data - Why is that negative?&lt;/a&gt;&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;Regarding the ability of the physically-based hydrological models to handle condensation, I'd say that it's difficult to give you a general answer: it will depend on the specific math behind the model, but my general guess would be that they do.&#xA;Even a simple &lt;a href=&quot;https://en.wikipedia.org/wiki/File:Tank_Model.jpg&quot; rel=&quot;noreferrer&quot;&gt;Bucket Model&lt;/a&gt;, would integrate condensation in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Water_balance&quot; rel=&quot;noreferrer&quot;&gt;water balance equation&lt;/a&gt;. While a more sophisticate Earth System Model would probably process it in the soil moisture and/or canopy component, in order to better represent these dynamics in the water-energy balance of the specific system. See for instance &lt;a href=&quot;https://gmd.copernicus.org/articles/12/4309/2019/gmd-12-4309-2019.pdf&quot; rel=&quot;noreferrer&quot;&gt;Longo et al 2019&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="8087" LastActivityDate="2020-09-22T07:21:02.357" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20236" PostTypeId="1" CreationDate="2020-09-22T17:38:19.853" Score="2" ViewCount="58" Body="&lt;p&gt;Many algorithms in remote sensing take one or more different datasets as inputs and return some output. An example might be computing the amount of sulfur dioxide (SO2) injected into the stratosphere after a volcanic eruption, having two main input datasets: 1) the SO2 amount and layer altitude (e.g., Eumetsat IASI Level-2 SO2 data) and 2) the altitude of the tropopause (e.g. NCEP/NCAR reanalysis data). Even though each input dataset contains multiple fields which are used in the computation, there are only two sources of data.&lt;/p&gt;&#xA;&lt;p&gt;I am working on a remote sensing tool that uses only one input dataset (containing multiple fields) which accomplishes a task that has previously required more than one dataset with quite a bit of uncertainty coming from the other datasets. I think that's kind of novel.&lt;/p&gt;&#xA;&lt;p&gt;Consequently, I am wondering if there is an existing name for an algorithm which uses only one dataset that distinguishes it from previous algorithms using multiple input sets?&lt;/p&gt;&#xA;&lt;p&gt;My instincts (read: &amp;quot;love of coffee&amp;quot;) tell me to refer to it as a &amp;quot;single-origin&amp;quot; algorithm, but surely there must be a name for this already.&lt;/p&gt;&#xA;&lt;p&gt;Any insight is greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="21121" LastActivityDate="2020-10-23T02:03:10.320" Title="Is there a name for a type of algorithm or processing which uses only one source of data as input?" Tags="|remote-sensing|data-analysis|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20237" PostTypeId="1" CreationDate="2020-09-22T18:53:04.657" Score="4" ViewCount="92" Body="&lt;p&gt;I noticed that Paulette (2020) is still a named storm and is now approaching northern Africa and Spain.  It is forecast to begin moving west again in the coming week.  Has a hurricane / tropical storm ever came back after making the trip back to the eastern Atlantic?&lt;/p&gt;&#xA;" OwnerUserId="21122" LastActivityDate="2020-09-22T18:53:04.657" Title="Has a hurricane ever crossed the Atlantic Ocean more than once?" Tags="|meteorology|weather-forecasting|severe-weather|extreme-weather|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20238" PostTypeId="1" CreationDate="2020-09-22T20:22:37.453" Score="2" ViewCount="99" Body="&lt;p&gt;A hot molten core is important for making the Earth geologically active. I believe most of the heat is from the time of the planet formation, and the high pressures due to everything pushing down to the core. How much of this can be attributed to radioactivity? How can we know it for sure, considering the pressure and temperature make it in accessible? Research show that radioactive potassium plays a role in it, but if it is true the how can a light element such as potassium sink to the core where it can generate heat by radioactive decay?&lt;/p&gt;&#xA;" OwnerUserId="21123" LastActivityDate="2020-09-23T01:49:37.120" Title="How much role does radioactivity play in making Earth geologically active" Tags="|geology|core|radioactivity|" AnswerCount="1" CommentCount="2" ClosedDate="2020-09-24T04:51:19.170" ContentLicense="CC BY-SA 4.0" />
  <row Id="20239" PostTypeId="2" ParentId="20238" CreationDate="2020-09-23T01:49:37.120" Score="1" Body="&lt;p&gt;The idea that the heat of the earth is from the time of its formation dates back to the late 1800s before radioactivity was known.  Unfortunately for that theory it was shown that an initial blob of molten rock would cool to a solid chunk, radiating its heat into space, in a few tens of millions of years.&lt;/p&gt;&#xA;&lt;p&gt;When radioactivity was discovered it was seen as a way out of the problem but the known radioactive elements were sufficiently rare in the earth's makeup that they couldn't provide enough heat.  Finally in the fifties the bulk composition  of the earth and the occurrence of radioactive isotopes were well enough known that it was shown that there is enough radioactive potassium, with a long enough half life, to provide the observed heat flux from the earth's interior.  Most of the heat is generated in the mantle, not the core since, as you point out, that is where the potassium is.  The mantle is also the layer that has convection currents in it to release that heat and drive plate tectonics.&lt;/p&gt;&#xA;&lt;p&gt;The outer core is liquid because, at the pressure it is under,  being a liquid is the thermodynamically stable state of the heavy core minerals.  The ice under a skater's blade turns into a thin layer of water under the passing skater's pressure, lubricating the passage of the skate.  The water does not warm up much, it is still below freezing, but it is not stable as a solid under the pressure of the skate. As soon as the pressure is released the water returns to ice which is the stable state of H2O at atmospheric pressure and sub-freezing temperatures.  Similarly the outer core is liquid because that is its stable state given the pressure and temperature at that depth.&lt;/p&gt;&#xA;&lt;p&gt;Increase the pressure more, as happens as you go deeper, and the stable state of the core material is a solid.  This explains the reason the inner core is solid.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2020-09-23T01:49:37.120" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20240" PostTypeId="2" ParentId="20236" CreationDate="2020-09-23T01:58:12.470" Score="1" Body="&lt;p&gt;I think you are thinking of an &lt;a href=&quot;https://en.wikipedia.org/wiki/Injective_function&quot; rel=&quot;nofollow noreferrer&quot;&gt;injective function&lt;/a&gt;  or mapping.&lt;/p&gt;&#xA;&lt;p&gt;However this work you are doing sounds sort of suspect.  Usually adding additional data (with appropriate cleaning) reduces uncertainty.  If the additional data is adding to the uncertainty that might indicate that the original data set is noisy or unreliable.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2020-09-23T01:58:12.470" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20241" PostTypeId="1" AcceptedAnswerId="20244" CreationDate="2020-09-23T04:41:51.260" Score="1" ViewCount="22" Body="&lt;p&gt;I was working with SO2 column data product from &lt;a href=&quot;https://disc.gsfc.nasa.gov/datasets/OMSO2_003/summary?keywords=OMI%20Total%20Column%201-Orbit%20L2%20Swath&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://disc.gsfc.nasa.gov/datasets/OMSO2_003/summary?keywords=OMI%20Total%20Column%201-Orbit%20L2%20Swath&lt;/a&gt;&#xA;I wanted to know, is the cloudfraction data in SO2 column an accurate measure of the Sulphur Dioxide present in an area?&lt;/p&gt;&#xA;" OwnerUserId="21124" LastActivityDate="2020-09-23T22:17:15.627" Title="Is cloudfraction a proper measure of gaseous data expanse?" Tags="|weather-satellites|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20242" PostTypeId="1" AcceptedAnswerId="20243" CreationDate="2020-09-23T11:05:26.650" Score="26" ViewCount="5851" Body="&lt;p&gt;Why is it that the volcanoes found in the Tharsis Montes region near the Martian equator, (one of which is Olympus Mons) so much larger than those found on Earth. In comparison, Hawaii's Mauna Loa, the tallest volcano on Earth, only rises 10 km above the sea floor. Olympus Mons rises three times higher than Earth's highest mountain peak, Mount Everest. What makes these volcanoes rise to such enormous heights in Mars, when comparing to those found on Earth and the rest of the Solar System?&lt;/p&gt;&#xA;" OwnerUserId="21123" LastActivityDate="2022-03-14T11:10:28.320" Title="Why is Olympus Mons the largest volcano in the whole solar system?" Tags="|volcanology|mountains|mars|mountain-building|" AnswerCount="3" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="20243" PostTypeId="2" ParentId="20242" CreationDate="2020-09-23T12:20:12.597" Score="50" Body="&lt;p&gt;This is mostly due to the fact that &lt;strong&gt;Mars does not have plate tectonics. Therefore the plate stays above the hotspot without moving, allowing magma to rise and pile up at the same place&lt;/strong&gt; for millions and millions of years. Above the Hawaii hotspot, the oceanic plate is moving, so volcanism tends to drift away with time (actually the volcanism happens at the exact same place from a mantle point a view, but its surface expression moves with the plate). It's why rocks of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hawaiian%E2%80%93Emperor_seamount_chain&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hawaiian-Emperor seamount chain&lt;/a&gt; are older in the West and younger in the East. This is true even at the scale of Hawaii island itself, where Kohala and Mauna Kea are extinct, while volcanism&lt;span class=&quot;math-container&quot;&gt;$-$&lt;/span&gt;or rather the plate&lt;span class=&quot;math-container&quot;&gt;$-$&lt;/span&gt;has shifted to Mauna Loa, Kīlauea and Kamaʻehuakanaloa.&lt;/p&gt;&#xA;&lt;p&gt;Imagine if all the magma comprising these islands had piled up at the same place, it could have built a gigantic volcano like Olympus Mons! Well... not really. There is another parameter to account for: a theoretical limit to how high a mountain can possibly get, because of compressive strength of rock (or glacial erosion in some theories). See for instance answers in these questions:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/9745/18081&quot;&gt;How high can a mountain possibly get?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/5407/18081&quot;&gt;Why is Mauna Kea taller than the maximum height possible on Earth?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;On Earth the limit is ~10 km. So even if magma kept piling up at the same place, the resulting mountain would start to laterally spread or collapse. But on Mars gravitational acceleration is lower, making the limit much higher.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2022-03-14T11:10:28.320" LastActivityDate="2022-03-14T11:10:28.320" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="20244" PostTypeId="2" ParentId="20241" CreationDate="2020-09-23T22:17:15.627" Score="2" Body="&lt;p&gt;No, cloud fraction is not a good measure of &lt;span class=&quot;math-container&quot;&gt;$\ce{SO_2}$&lt;/span&gt;. Clouds are functions of moisture, temperature, and cloud condensation nuclei. Som of the other variables, such as (but not limited to) &lt;code&gt;ColumnAmountSO2&lt;/code&gt; or &lt;code&gt;ColumnAmountSO2_TRL&lt;/code&gt;are better indicators.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-09-23T22:17:15.627" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20245" PostTypeId="1" AcceptedAnswerId="20248" CreationDate="2020-09-24T10:26:00.020" Score="2" ViewCount="88" Body="&lt;p&gt;I have been doing some DIYnamics with rotating water and non-rotating water. So I had a bucket filled with water on a rotating table, and waited for it to be in solid body rotation. I then dropped some droplets of fooddye in the water. I observed that the dye sank vertical to the bottom of the bucket without mixing with the water horizontally. I remember that my teather called this 2D turbulence. However, I can't find a reason for why the dye does not mix horizontally. What is so special with rotating water, that makes 2D tubulence occur and not 3D?&lt;/p&gt;&#xA;&lt;p&gt;After this experiment was done, we added more dye. But now we mixed it gently with a stroke of a pen, to make turbulence. I then see some spirals being formed, so the water must mix a bit horizontally now. But why? And how does the rotating water affect turbulence?&lt;/p&gt;&#xA;" OwnerUserId="21126" LastActivityDate="2020-09-24T17:13:08.790" Title="How does rotating water affect turbulence?" Tags="|geophysics|earth-rotation|turbulence|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20246" PostTypeId="1" CreationDate="2020-09-24T10:55:11.193" Score="1" ViewCount="319" Body="&lt;p&gt;When the Earth was at its warmest, and there were no ice caps at all, not even during the winter, and thermal expansion meant a certain amount of water took up more space, what ratio of Earth's surface was covered in water?&lt;/p&gt;&#xA;&lt;p&gt;Also, how much more expansive was water back then? 5% or so?&lt;/p&gt;&#xA;" OwnerUserId="20985" LastActivityDate="2020-10-25T02:01:15.113" Title="How much of the Earth's surface was covered with water during the Mesozoic?" Tags="|climate-change|climate|temperature|paleoclimatology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20248" PostTypeId="2" ParentId="20245" CreationDate="2020-09-24T17:13:08.790" Score="1" Body="&lt;p&gt;The dye diffuses vertically because it has a higher density. So when you put the dye in from the top, it wants to go to the bottom, albeit slowly. If it were more buoyant, it would float. It does diffuse horizontally, though much slower. This can be shown that, after a long time, the water will turn the color of the dye.&lt;/p&gt;&#xA;&lt;hr&gt;&#xA;&lt;p&gt;As far as rotation affecting the dye, that is complicated. If you start the rotation before you put the dye in, you can get &lt;a href=&quot;http://weathertank.mit.edu/links/projects/taylor-columns-introduction&quot; rel=&quot;nofollow noreferrer&quot;&gt;Taylor Columns&lt;/a&gt;. Throw in different variables/change different things about the tank, and you can find different phenomenon (see the &lt;a href=&quot;http://weathertank.mit.edu/links/projects&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weather in a tank experiments&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;What you see in your experiment is called &amp;quot;shear-induced diffusion.&amp;quot; The movement of your pen makes shear, and that shear increases the diffusion rate. I would also think that the eddies generated help diffuse the dye.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-09-24T17:13:08.790" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20249" PostTypeId="2" ParentId="20242" CreationDate="2020-09-24T19:46:19.213" Score="9" Body="&lt;p&gt;The other answer is already pretty good: No plate tectonics and no water erosion allows material to pile up in one place, and then stay put. Neither is the case on earth: The plate moves away from the hot spot, transporting built up rocks with it and causing the magma to find another outlet a few miles over. Hawaii also tends to be a place where you can see water erosion happen in a pretty spectacular way.&lt;/p&gt;&#xA;&lt;p&gt;There is one other reason, though: Earth's tectonic plates are not very thick -- oceanic plates, for example, are only 10-20 km thick. They bend down even just under an ice sheet like during the ice ages (or in Antarctica today). This process is called &amp;quot;isostatic adjustment&amp;quot;, and you can think of it as the plate just sinking down into the region below that consists of a (somewhat) liquid state of rock which just moves to the side. It's a bit like when you step onto an ice floe: it just sinks down a bit. If this already happens with an ice sheet 1000 meters thick, imagine what would happen if you piled 30 km of rocks on top of a plate: it would just keep sinking down. In essence, every time you'd erupt some more lava and put it on top, the plate along with the base of the mountain would sink down a bit further. Mountains don't tend to build up very high in this process.&lt;/p&gt;&#xA;&lt;p&gt;Why is this not happening on Mars? Because Mars is relatively small, and its interior has long cooled down to a degree where the crust (the solid part of the earth that on Earth consists of the tectonic plates) is vastly thicker: Many 100s of km thick, possibly all the way down to the core-mantle boundary. A result of this is that they can support vastly larger loads without crumbling or sinking into the more liquid layer beneath. As a result, they crust on Mars can support mountains that the plates on Earth could not.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastEditorUserId="5259" LastEditDate="2021-01-04T22:11:30.977" LastActivityDate="2021-01-04T22:11:30.977" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20250" PostTypeId="1" AcceptedAnswerId="20302" CreationDate="2020-09-24T19:47:03.247" Score="1" ViewCount="112" Body="&lt;p&gt;So the first problem I'm stuck on is this one:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;em&gt;An airmass is moving down a mountain from point A to B. At A the temperature is -10 Celsius and the pressure is 890hPa. At point B the pressure is 1010 hPa. What is the temperature to the air when reaching point B (assuming the airmass is isolated)?&lt;/em&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;So I thought about using the ideal gas law and &lt;span class=&quot;math-container&quot;&gt;$P_1/P_2=T_1/T_2$&lt;/span&gt;, but I'm not sure if that is correct. The numbers I get don't look right.&lt;/p&gt;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;&lt;em&gt;The pilot on an airplane thinks it's time to get some fresh air in the cabin. The airpressure outside is 350 hPa and the temperature is -40 Celsius, and the pressure needs to be increased to 850 hPa before being brought into the cabin. This is an adiabatic process. After being compressed what is the temperature of the air?&lt;/em&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;My teacher says that we need to use &lt;a href=&quot;https://atmos.washington.edu/%7Erobwood/teaching/ThermoHomework_WithAns_2014.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;the following t-skew diagram&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;But I don't understand how to use it in the problem, and which of the lines that represent an adiabatic process.&lt;/p&gt;&#xA;" OwnerUserId="21126" LastEditorUserId="2958" LastEditDate="2020-10-26T07:54:48.183" LastActivityDate="2020-10-26T07:54:48.183" Title="How do I find the temperature of the air mass, and how do I use a t-skew chart?" Tags="|meteorology|temperature|homework|thermodynamics|pressure|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20251" PostTypeId="2" ParentId="20246" CreationDate="2020-09-25T01:28:17.250" Score="2" Body="&lt;p&gt;At that time there were large areas of shallow seas, so small differences in elevation could lead to large differences in water area. I doubt that the elevations are well enough known to estimate the area precisely.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://dinosaurpictures.org/ancient-earth/#90&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://dinosaurpictures.org/ancient-earth/#90&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The coefficient of expansion of water is only &lt;span class=&quot;math-container&quot;&gt;$207 \times 10^{-6}/K$&lt;/span&gt;. 15 degrees would give 0.3%.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2020-09-25T01:28:17.250" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20252" PostTypeId="2" ParentId="5407" CreationDate="2020-09-25T03:38:39.667" Score="1" Body="&lt;p&gt;Basaltic rock is denser than granitic rock and that makes the difference. Also since 2/3 of the mountain is underwater thousands of feet of water are pressing against it to take yield of it's weight. it's like a 300 lb man, jumps in the pool, takes enormous weight pressure off.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-09-25T03:38:39.667" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20253" PostTypeId="2" ParentId="20221" CreationDate="2020-09-25T03:56:24.643" Score="0" Body="&lt;p&gt;It's doable &amp;quot;Ecospheres&amp;quot; is a self-sustaining ecosystem, you never have to feed the life within. Simply provide your EcoSphere with a source of indirect natural or artificial light. They use small sea worms, filamentous algae, shrimp and microbes.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-09-25T03:56:24.643" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20255" PostTypeId="2" ParentId="2535" CreationDate="2020-09-25T04:21:57.387" Score="0" Body="&lt;p&gt;Fire’s role in dry land ecology (especially of the US West) is well understood. It's fire suppression that led to the disasters we have now.&#xA;Fire fills an important niche in warmer ecosystems; It substitutes the role normally reserved for soil decomposers (Fungi/bacteria), but burning the woody debris and vegetation it frees up material and and soluable soil carbon thats essential to plant growth.&#xA;– it sweeps away weeds that choke the forest floor, allowing successor trees to continue to proliferate. Giant sequoia breeds this way&#xA;– eliminates competitive weeds/invasives&#xA;– reintroduces nutrients (ash) back into the soil, with dry ecology; wood doesn't decompose at a fast rate; so fire converts wood/plants into ash which is water soluable.&#xA;– produces ethylene gas (a natural plant growth booster)&#xA;– heat/smoke of the fire heats up cones in conifer trees to open and release their seeds&#xA;– triggers plants lying dormant in the soil&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-09-25T04:21:57.387" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20258" PostTypeId="2" ParentId="13055" CreationDate="2020-09-25T06:20:53.287" Score="2" Body="&lt;p&gt;The same thing that typically cause them,.... Lightning.&#xA;a very small percentage started by spontaneous combustion of dry fuel such as sawdust and leaves.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-09-25T06:20:53.287" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20259" PostTypeId="2" ParentId="14361" CreationDate="2020-09-25T06:36:04.690" Score="0" Body="&lt;p&gt;Fire has been apart of natural ecology for as long as land plants existed. The Silurian period(420 million years ago) high light the most examples of fossil charcoal indicating wild fire&#xA;Fire’s role in dry land ecology (especially of the US West) is well understood. It's fire suppression that led to the disasters we have now. Fire fills an important niche in warmer ecosystems like scrublands, grassland, chapparrals and dryer forests; It substitutes the role normally reserved for soil decomposers (Fungi/bacteria), but burning the woody debris and vegetation it frees up material and and soluble soil carbon that's essential to plant growth. – it sweeps away weeds that choke the forest floor, allowing successor trees to continue to proliferate. Giant sequoia breeds this way – eliminates competitive weeds/invasives – reintroduces nutrients (ash) back into the soil, with dry ecology; wood doesn't decompose at a fast rate; so fire converts wood/plants into ash which is water soluable. – produces ethylene gas (a natural plant growth booster) – heat/smoke of the fire heats up cones in conifer trees to open and release their seeds – triggers plants lying dormant in the soil&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-09-25T06:36:04.690" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20260" PostTypeId="1" AcceptedAnswerId="20274" CreationDate="2020-09-25T08:08:09.457" Score="2" ViewCount="139" Body="&lt;p&gt;While hiking Hyndman Peak in Idaho a couple weeks ago we noticed a rock slide that appeared to be formed by a glacier, however it was on the west side of the mountain. It was also strange that the downhill face was fairly sharp and was dirt/gravel instead of large rock. I only have a few smokey photos, and the satellite image is pretty poor, but just curious if anyone had any ideas.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.com/maps/@43.7396281,-114.1266807,14.5z/data=!5m1!1e4?hl=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;Location in google maps&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JkbAS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JkbAS.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xC1P8.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xC1P8.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/67F0b.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/67F0b.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/O7yIA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/O7yIA.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OrMNC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OrMNC.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21138" LastActivityDate="2020-09-30T21:15:23.177" Title="What formed this rock slide formation near Hyndman Peak Idaho (photos)?" Tags="|geology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20263" PostTypeId="2" ParentId="20260" CreationDate="2020-09-25T22:26:11.527" Score="0" Body="&lt;p&gt;Some kind of &amp;quot;rock glacier&amp;quot; or moraine?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ZRs9Z.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZRs9Z.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://sp.lyellcollection.org/content/320/1/85/tab-figures-data&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2020-09-28T01:40:53.960" LastActivityDate="2020-09-28T01:40:53.960" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20264" PostTypeId="2" ParentId="4326" CreationDate="2020-09-26T03:29:41.353" Score="0" Body="&lt;p&gt;Plants sweat. It's called transpiration.&#xA;. Nearly 90% of this water exits the tree in the form of vapor through small pores called stomata on leaves. Atmospheric circulation moves water vapor around the globe, but oceanic evaporation meets most of it. It accumulates and falls as rain, which plants absorb, in high heat, they plants release water to dispose of heat and it accumulates again. COllecting to afix new humidity which fall as rain once again.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/y1O5K.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/y1O5K.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-09-26T03:29:41.353" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20266" PostTypeId="1" AcceptedAnswerId="20267" CreationDate="2020-09-27T08:38:07.767" Score="1" ViewCount="78" Body="&lt;p&gt;I am trying to download transpiration and snow cover data from earth data but unable to figure out how to do that&lt;/p&gt;&#xA;" OwnerUserId="18076" LastActivityDate="2020-09-27T08:38:07.767" Title="How to download FLDAS data from earth data" Tags="|atmosphere|weatherdata|nasa|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20267" PostTypeId="2" ParentId="20266" CreationDate="2020-09-27T08:38:07.767" Score="1" Body="&lt;p&gt;To download the data from earth data, the following needs to be done&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Go to &lt;a href=&quot;https://urs.earthdata.nasa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://urs.earthdata.nasa.gov/&lt;/a&gt; and create an account. Note the username and password which will be used to download the data.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;In your linux root create a file .netrc and enter the following&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;machine urs.earthdata.nasa.gov login your_login password your_password&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Go to &lt;a href=&quot;https://disc.gsfc.nasa.gov/datasets&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://disc.gsfc.nasa.gov/datasets&lt;/a&gt; and search your dataset of interest and then click it&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;4.On the right hand side you will see a get data button, click that button.&lt;/p&gt;&#xA;&lt;p&gt;5.Now a dialog box will open, click get data&lt;/p&gt;&#xA;&lt;ol start=&quot;6&quot;&gt;&#xA;&lt;li&gt;&lt;p&gt;Now another dialog box will open, click download links list, a list of the files will get downloaded.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Now in the terminal fire the following command&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;wget --load-cookies ~/.urs_cookies --save-cookies ~/.urs_cookies --auth-no-challenge=on --keep-session-cookies --content-disposition -i &amp;lt;url.txt&amp;gt;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Meanwhile before step 7 two things need to be done. One, you need to just create this file ~/.urs_cookies and the second is that you have to authorize the data that you are downloading.&lt;/p&gt;&#xA;" OwnerUserId="18076" LastActivityDate="2020-09-27T08:38:07.767" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20268" PostTypeId="2" ParentId="14101" CreationDate="2020-09-28T05:21:48.317" Score="-1" Body="&lt;p&gt;What kind of forest, 45,000 acres of What?&#xA;If it's boreal forest it's a slow carbon sink&#xA;If its tropical, it'll be faster&lt;/p&gt;&#xA;&lt;p&gt;Forests are largely carbon neutral in terms of carbon emissions. In temperate forests they emit carbon when they go inert for the season.Trees are roughly 50% carbon (dry weight) by mass. Increases in standing timber are directly correlated with increases in bound carbon. But once those trees die they decompose to anerobic co2 again. To grow a pound of wood, a tree uses 1.47 pounds of carbon dioxide and gives off 1.07 pounds of oxygen. An acre of trees might grow 4,000 pounds of wood in a year, using 5,880 pounds of carbon dioxide and giving off 4,280 pounds of oxygen in the process. However deciduous temperate forests put out co2. Tree's with Long life spans and ideal growing conditions are however better carbon sinks, as they accumulate cellulose they sequester carbon. Once they're mature they slow down and become carbon neutral. Trees that largely never stop growing are good carbon sinks&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;Redwoods&#xA;Eucalyptus&#xA;douglas fir&#xA;Lawson cypress&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Tall Tropical specimens&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;Koompassia&#xA;Menara&#xA;Bertholletia (Brazil Nut)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-09-28T05:21:48.317" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20269" PostTypeId="1" CreationDate="2020-09-28T13:00:44.887" Score="3" ViewCount="392" Body="&lt;p&gt;I'm looking for a mathematical method to estimate the river width based on the basic topographic information of the specific sections of stream under consideration.&lt;/p&gt;&#xA;&lt;p&gt;Is there a formula to estimate the river width in a specific point based on the upstream contributing area (or any other relation with the geo-morphological characteristics of flow accumulation)?&#xA;Could you please also refer to the corresponding literature?&lt;/p&gt;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="8087" LastEditorUserId="8087" LastEditDate="2020-09-28T14:20:47.340" LastActivityDate="2020-09-28T21:26:44.640" Title="Calculation of river width in relation to contributing area" Tags="|hydrology|rivers|topography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20270" PostTypeId="2" ParentId="20269" CreationDate="2020-09-28T21:26:44.640" Score="3" Body="&lt;p&gt;It's a function of flow volume rather than catchment area. The flow rate can be vary by an order of 10 to 100 for the same catchment area, &lt;a href=&quot;https://www.google.com/search?q=average+river+width+based+on+flow+volume&amp;amp;tbm=isch&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.google.com/search?q=average+river+width+based+on+flow+volume&amp;amp;tbm=isch&lt;/a&gt; There's so many variables like flow speed, inclination, bedrock type, flow rate.&lt;/p&gt;&#xA;&lt;p&gt;This document includes the river width, it says there are too many variables.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/s41598-019-44347-4&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/s41598-019-44347-4&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://link.springer.com/article/10.1007/s11629-014-3265-0&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://link.springer.com/article/10.1007/s11629-014-3265-0&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;here's a cool reference:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL082027&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2019GL082027&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Did you know that a given type of rock gives mountains with all the same slope angles, i.e. there are mountains with ravines averaging 23 or 14 or 33 or 50% for the same mountain group, and screes inclines are rarely an irregular mix.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastActivityDate="2020-09-28T21:26:44.640" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20271" PostTypeId="1" CreationDate="2020-09-29T13:15:09.423" Score="1" ViewCount="34" Body="&lt;p&gt;I am looking for a database or api that stores historical data of very low visibility conditions. The data needs to be reliable and consistent without too many gaps and in an interval of 1 hour.&lt;/p&gt;&#xA;&lt;p&gt;The best sources I have found have a resolution of 1/4 mile (400m) or worse.&lt;/p&gt;&#xA;&lt;p&gt;Is there a source with better resolution? Perhaps 100m? Is it even possible to measure it in a higher resolution?&lt;/p&gt;&#xA;" OwnerUserId="21161" LastEditorUserId="6016" LastEditDate="2020-09-29T15:55:14.080" LastActivityDate="2020-09-29T15:55:14.080" Title="Weather data of very low visibility" Tags="|severe-weather|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20272" PostTypeId="1" CreationDate="2020-09-29T22:24:01.673" Score="1" ViewCount="59" Body="&lt;ol&gt;&#xA;&lt;li&gt;&lt;strong&gt;You are flying 2.5 km over the ground while your mates are flying up at 350 hPa. All the way between you there are clouds. If you measure that the temperature outside is 4 celsius, what temperature do they measure?&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Don't really know where to start, to be honest. I don't find an equations in my book that seem reasonable to solve this task.&lt;/p&gt;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;&lt;strong&gt;You are in an airplane 2.5 km above the ground. Assume that the atmosphere can be treated as a Standard Atmosphere. The temperature outside is 4 Celsius. You look down toward the ground and see no clouds. What is the expected temperature of the ground?&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Should I just use the adiabatic lapse rate?&lt;/p&gt;&#xA;" OwnerUserId="21126" LastActivityDate="2020-09-29T22:24:01.673" Title="How do I find the temperature measured at 350 hPa?" Tags="|geophysics|temperature|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20273" PostTypeId="1" CreationDate="2020-09-30T06:07:43.593" Score="1" ViewCount="2014" Body="&lt;p&gt;Two pieces of quartz people have given to me at different times have become gradually clear over the space of a few years. Previously they were very cloudy, translucent without any detail visible through them. Under a 10x hand lens they appeared to have numerous tiny inclusions or fracture scattered throughout. Now I am able to hold the specimens on a book and clearly read text through them.&lt;/p&gt;&#xA;&lt;p&gt;What was the nature of the visual obstructions and what is the mechanism by which the obstructions disappeared?&lt;/p&gt;&#xA;" OwnerUserId="21163" LastActivityDate="2022-11-12T02:50:20.890" Title="Why and how do quartz crystals change from cloudy/translucent to clear/transparent?" Tags="|mineralogy|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20274" PostTypeId="2" ParentId="20260" CreationDate="2020-09-30T12:11:13.940" Score="3" Body="&lt;p&gt;It is a normal rock slide, AKA a landslide, they happen all the time.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lAVLC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lAVLC.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;If a slope is not stable the rock collapses, landslides are very common and can be triggered by almost anything from rain, to imperceptible quakes, to simple erosion.&lt;/p&gt;&#xA;&lt;p&gt;It could be rotational or translational the two blur together anyway. Most likely just a shallow rotational landslide.&lt;/p&gt;&#xA;&lt;p&gt;The lower areas of a mountain being made of debris is extremely common, it is called a Scree slope. Where do you think all the rock that is eroded off the upper portions go?&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="2470" LastEditDate="2020-09-30T21:15:23.177" LastActivityDate="2020-09-30T21:15:23.177" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20276" PostTypeId="2" ParentId="17662" CreationDate="2020-09-30T17:19:20.560" Score="1" Body="&lt;p&gt;&lt;a href=&quot;https://crc806db.uni-koeln.de/dataset/show/lgm-paleoenvironment-of-europe--map1449850675/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This map&lt;/a&gt; should address at least part of your question&#xA;&lt;a href=&quot;https://i.stack.imgur.com/U54DP.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/U54DP.jpg&quot; alt=&quot;LGM Paleoenvironment of Europe&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The here documented GIS map and dataset contains a collection of Last&#xA;Glacial Maximum (LGM, ~21k yBP) paleoenvironmental data. It is the&#xA;first result of a project that aims to acquire, produce and publish&#xA;GIS datasets from non-GIS based sources such as analogous maps,&#xA;textual informations or figures of scientific publications for&#xA;prehistoric time slices. In combination with modelling results and&#xA;already available GIS-datasets related to the mentioned time frame, it&#xA;should enable other researchers and members from other projects to use&#xA;the maps in their work, properly cited and referenced. The map shows&#xA;LGM land ice sheets, paleo-stream networks and inland water in Europe,&#xA;a sea-level adapted (-120m) land mass and a Köppen-Geiger climate&#xA;classification derived from climate model data.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I know this is more broadly a field of active study and there is a relatively new method of analyzing &lt;a href=&quot;https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-6326-5_158-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;cosmogenic nuclides&lt;/a&gt; to determine for what duration a surface has been exposed to cosmic radiation.&lt;/p&gt;&#xA;&lt;p&gt;Broadly how this works is that surfaces exposed to cosmic radiation start to develop an isotopic signature, to the degree that you can tell how long a boulder has been exposed to the open sky (within a margin of error).&lt;/p&gt;&#xA;&lt;p&gt;Joerg M. Schaefer of Lamont-Doherty Earth Observatory explains in &lt;a href=&quot;https://link.springer.com/referenceworkentry/10.1007%2F978-94-007-6326-5_158-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Glacial Landscape (Cosmogenic Nuclide)&lt;/a&gt; in the Encyclopedia of Scientific Dating Methods:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;High-sensitivity cosmogenic nuclide techniques applied to the moraine&#xA;record now afford for &lt;strong&gt;precise reconstruction of past glacier&#xA;fluctuations with centennial resolution and on a time scale ranging&#xA;from decades to beyond 100,000 years.&lt;/strong&gt; It has been a long-standing&#xA;dream of geologists and climate scientists alike to precisely map land&#xA;ice change during the last ice age through the deglaciation period and&#xA;into the current interglacial, referred to as the Holocene.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2020-09-30T17:19:20.560" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20277" PostTypeId="1" CreationDate="2020-09-30T17:26:03.370" Score="3" ViewCount="64" Body="&lt;p&gt;Everyone has heard of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cascadia_subduction_zone&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cascadia Subduction Zone&lt;/a&gt; and the potential threat it poses. However, I have heard nothing about The Cocos Subduction Zone, even though it caused a &lt;a href=&quot;https://en.wikipedia.org/wiki/2017_Chiapas_earthquake&quot; rel=&quot;nofollow noreferrer&quot;&gt;devastating earthquake&lt;/a&gt; over 3 years ago. Does the Cocos Subduction zone pose the same threat to Mexico as the Cascadia Subduction zone to the US and Canada?&lt;/p&gt;&#xA;" OwnerUserId="21165" LastEditorUserId="6016" LastEditDate="2020-09-30T21:37:47.550" LastActivityDate="2020-09-30T21:37:47.550" Title="Is it possible for Mexico to have a magnitude 9 earthquake?" Tags="|geology|geophysics|plate-tectonics|earthquakes|seismology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20278" PostTypeId="1" CreationDate="2020-09-30T18:50:55.227" Score="2" ViewCount="170" Body="&lt;p&gt;California is one of the few places in the world that lie on a transform fault. My question is why considering the fact that North American Plate is moving westward shouldn't California be a subduction zone like the Entirety of the west coast of the Americas say for Canada. Why is that the North American plate is simply rubbing up against Pacific plate in here as well as Canada.&lt;/p&gt;&#xA;" OwnerUserId="21165" LastEditorDisplayName="user20559" LastEditDate="2021-05-19T10:45:31.637" LastActivityDate="2021-05-19T10:45:31.637" Title="Will California become a subduction zone in the distant future" Tags="|geology|geophysics|plate-tectonics|subduction|california|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20282" PostTypeId="2" ParentId="16459" CreationDate="2020-10-02T17:45:21.383" Score="1" Body="&lt;p&gt;NO, it's not a very major sink on our planet, red is the extra carbon from human activities: &lt;a href=&quot;https://jancovici.com/en/climate-change/ghg-and-carbon-cycle/wont-the-carbon-sinks-absorb-the-extra-co2/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://jancovici.com/en/climate-change/ghg-and-carbon-cycle/wont-the-carbon-sinks-absorb-the-extra-co2/&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/m78IJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/m78IJ.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Cool theory about Venus. It lacks a strong magnetosphere, so the solar wind carries away more light elements like hydrogen, and water vapor, the solar wind has carried away all the seas of venus since about 2 billion years ago, probably aided by the sun being 30% bigger and hotter there.&lt;/p&gt;&#xA;&lt;p&gt;So, if Venus had kept it's CO2 levels in check, it would probably have sunk them in limestone, and also weathering if there was tectonic activity. Weathering does account for 0.2 to 1 gigaton of CO2 sink every year, compared to 30 gigatons released every year from fossil fuels.&lt;/p&gt;&#xA;&lt;p&gt;The primary store of carbon in the earth's surface is in limestone, comprising about 60,000,000 gigatons of carbon, and coal and oil. the total amount of carbon near the surface of the earth is &lt;a href=&quot;https://undeerc.org/pcor/sequestration/cycle.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt; 120 million GtC. Life exists on our planet since about 3.8 billion years, so it could have survived in Venusian oceans until about 2 billion years ago. That's the same time that the first major limestone layers appear on earth about 2.4-2.8 billion years ago. &lt;a href=&quot;https://www.skepticalscience.com/weathering.html#significance&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.skepticalscience.com/weathering.html#significance&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2020-10-02T19:49:09.487" LastActivityDate="2020-10-02T19:49:09.487" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20283" PostTypeId="1" CreationDate="2020-10-04T13:18:52.847" Score="1" ViewCount="70" Body="&lt;p&gt;Observations&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;There is a higher level of PM2.5 pollution outside of the house. Readings are in the 80-150 range due to wildfires. (PM2.5 levels determined by sensors in PurpleAir.com's sensor network)&lt;/li&gt;&#xA;&lt;li&gt;Using a handheld air monitor that can measure PM2.5 readings were taken indoors.&lt;/li&gt;&#xA;&lt;li&gt;Most rooms in the house are reading +/- 40, but one room read 450&lt;/li&gt;&#xA;&lt;li&gt;smokey haze could be seen in the room during the highest readings (what alerted us to the problem)&lt;/li&gt;&#xA;&lt;li&gt;relative humidity outside is typically low (30-40%)&lt;/li&gt;&#xA;&lt;li&gt;the room with the high reading (450 PM2.5) has&#xA;&lt;ul&gt;&#xA;&lt;li&gt;high humidity (80-90%) to support tropical plants&lt;/li&gt;&#xA;&lt;li&gt;windows from the 1990s (older, don't seal well)&lt;/li&gt;&#xA;&lt;li&gt;an attic access panel that allows some air movement&lt;/li&gt;&#xA;&lt;li&gt;no fans that would draw in air from outside or push air outside&lt;/li&gt;&#xA;&lt;li&gt;room is long and skinny (40'x15') with windows along the long axis and has a door halfway down the 40' axis&lt;/li&gt;&#xA;&lt;li&gt;one end has higher humidity (where the humidifier is)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;putting 3 small HEPA filters in the room can reduce PM2.5 to 5 in about an hour. After about 10 hours, readings of PM2.5 are much higher 80-400&lt;/li&gt;&#xA;&lt;li&gt;if we reduce the PM2.5 to under 10 and close the door halfway along the 40' axis of the room, the lower humidity side of the door stays free of PM2.5 whereas the PM2.5 on the higher humidity side of the door continues to increase.&lt;/li&gt;&#xA;&lt;li&gt;there is no internal source of PM2.5 - this only started this week as smoke has blown into the area&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;Q:&lt;/strong&gt; what's the likelihood that the humidity differential between indoors and outdoors is &amp;quot;pumping&amp;quot; air and effectively pulling smoke indoors?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Q.&lt;/strong&gt; What's the likelihood of the humidity differential being able to concentrate the smoke indoors (there have been no readings outside that come close to the 450 PM2.5 that was seen indoors, could the humidity differential be &amp;quot;pumping&amp;quot; pollution indoors &lt;em&gt;and&lt;/em&gt; concentrating it)?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Q.&lt;/strong&gt; what else might be contributing or causing this?&lt;/p&gt;&#xA;" OwnerUserId="20871" LastEditorUserId="20871" LastEditDate="2020-10-04T13:27:39.780" LastActivityDate="2020-11-06T21:02:10.227" Title="Can a Humidity Differential move PM2.5 Pollution?" Tags="|meteorology|atmosphere|pressure|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20284" PostTypeId="1" CreationDate="2020-10-04T17:29:04.870" Score="1" ViewCount="35" Body="&lt;p&gt;In researching economic damage from various pollutants, I often find that it's very random sources that inform me of various pollutants I need to be mindful of in calculations. Is there any kind of overarching list of known problematic pollutants that one needs to consider in calculations for environmental factors?&lt;/p&gt;&#xA;&lt;p&gt;For instance, you might have pesticides, heavy metal aerosols, heavy metal colloids and solutions, fertilizer runoff, sewage, etc. But, how do I know there aren't more? There must be some kind of standard list, maybe the European Union or one of the environmental agencies in North America has a list of pollution categories that damage the environment.&lt;/p&gt;&#xA;" OwnerUserId="21180" LastActivityDate="2020-10-04T18:40:57.913" Title="Is there a conventional list of pollutants to consider for calculations? Or an updating one even?" Tags="|water|air-pollution|environmental-protection|pollution|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20285" PostTypeId="2" ParentId="20284" CreationDate="2020-10-04T18:40:57.913" Score="1" Body="&lt;p&gt;In the USA there are two classifications of airborne pollutants. They are&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.epa.gov/criteria-air-pollutants&quot; rel=&quot;nofollow noreferrer&quot;&gt;Criteria Air Pollutants&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;There are 6 separate air pollutants. These make the bulk of the regulation, especially for &lt;a href=&quot;https://www.epa.gov/laws-regulations/summary-clean-air-act&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Clean Air Act&lt;/a&gt;. Each pollutant has different standards to adhere to. Examples include lead, ozone, and particulate matter.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.epa.gov/haps/initial-list-hazardous-air-pollutants-modifications&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hazardous Air pollutants&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;This is a list of 187 pollutants. These are cancer-causing pollutants, but are usually in pretty low concentrations. Examples include asbestos, lead, and benzene.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-10-04T18:40:57.913" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20286" PostTypeId="1" CreationDate="2020-10-05T03:42:22.200" Score="2" ViewCount="123" Body="&lt;p&gt;I have an idea for a novel I want to turn into a reality, and I'm starting some research first to make my book at least plausible in very specific conditions. The main aspect of the story would be focused around the Northwest Coast of the US after an earthquake has completely demolished everything, turning it into a post-apocalyptic wasteland.&#xA;The main question I'm attempting to answer currently is if this is even possible. I know the Sand Andreas fault line is a major concern presently due to its high capability to release an exorbitant amount of energy in a single quake, but given all the conditions were perfect, is it possible that a single earthquake could cause enough damage to rip apart the entire West Coast? And if not in a single earthquake, can one quake, given it was powerful enough to trigger a series of seismic activity all along the West Coast, cause such a catastrophic, apocalyptic event?&#xA;Any advice would be greatly appreciated, and thank you all for your time!&lt;/p&gt;&#xA;" OwnerUserId="21181" LastActivityDate="2021-03-18T20:54:00.207" Title="Is an Earthquake Large Enough to Cripple the Entire West Coast of North America Possible?" Tags="|earthquakes|seismology|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20287" PostTypeId="2" ParentId="20286" CreationDate="2020-10-05T07:15:20.610" Score="2" Body="&lt;p&gt;Never say never, but it's unlikely.&lt;/p&gt;&#xA;&lt;p&gt;Every geological fault is not uniform. There are bumps and snags of varying size and strength along its three intentional surfaces. As once fault surface moves over the other some of the snags can break off resulting in localized quakes at the site of the breakages.&lt;/p&gt;&#xA;&lt;p&gt;Similarly, for very strong, robust snags (protuberances) which ride over the other surface as they suddenly hit a dimple in the other surface or simply just ride along another surface protuberance on the surface of the other side of the fault it slams into the other surface. This causes another form of localized earthquake.&lt;/p&gt;&#xA;&lt;p&gt;For an earthquake to hit the entire north west region of the US, these type of events would have to occurs along the entire length of the fault simultaneously.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-10-05T07:15:20.610" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20291" PostTypeId="1" AcceptedAnswerId="20292" CreationDate="2020-10-06T21:56:07.897" Score="1" ViewCount="67" Body="&lt;p&gt;The USGS maps of coastal California label alluvial deposits as Qyf and Qof — the “younger” and “older” fans of coarse sediments. But in areas of the earth that never saw Quaternary glaciation (like California), does that distinction make any sense?&lt;/p&gt;&#xA;&lt;p&gt;More generally, in lower latitudes, how is “younger,” meaning Holocene, any different geologically from “Older,” meaning Pleistocene?&lt;/p&gt;&#xA;" OwnerUserId="21190" LastActivityDate="2020-10-07T08:17:58.980" Title="How are Quaternary alluvial deposits differentiated in subglacial latitudes?" Tags="|geology|glaciation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20292" PostTypeId="2" ParentId="20291" CreationDate="2020-10-07T08:17:58.980" Score="1" Body="&lt;p&gt;They seem to be differentiated according to their morphology, Qof deposits being highly dissected and more consolidated than Qyf, thus older. From &lt;a href=&quot;https://pubs.usgs.gov/of/2018/1024/ofr20181024_pamphlet.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;a random pamphlet&lt;/a&gt; of the map series:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Qyf&lt;/strong&gt; Alluvial fan deposits (Holocene)—Unconsolidated, heterogeneous layers of sand, silt, and gravel; relatively undissected; deposited by streams emanating from canyons onto alluvial plains; identified primarily by fan morphology and topographic expression. Internal contacts delineate individual alluvial fans&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Qof&lt;/strong&gt; Alluvial fan deposits (Pleistocene)—Discontinuous or highly dissected deposits of semiconsolidated, moderately to poorly sorted layers of silty clay, silt, sand, and gravel&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The pamphlet also states that &amp;quot;unit ages [...] reflect local stratigraphic relations&amp;quot;, so they are relative ages, not absolute dating.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-10-07T08:17:58.980" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20293" PostTypeId="2" ParentId="17104" CreationDate="2020-10-07T09:53:55.677" Score="3" Body="&lt;p&gt;Assuming the earth to be a perfect blackbody, the radiated power is given by:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\rm{P = A \cdot \sigma \cdot T^4}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where T is the blackbody temperature and sigma is the Stefan Boltzman constant.&lt;/p&gt;&#xA;&lt;p&gt;If the sun disappears, then the Earth's core supplies the heat. The flux of this heat is estimated at &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_internal_heat_budget&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;span class=&quot;math-container&quot;&gt;$91.6 \rm{\frac{mW}{m^2}}$&lt;/span&gt;&lt;/a&gt;.&#xA;Equating the two, we have&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\rm{91.6\frac{mW}{m^2} \cdot A = A \cdot \sigma T^4}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Which gives &lt;span class=&quot;math-container&quot;&gt;$\rm{T = 35.65 K}$&lt;/span&gt; at the surface.&lt;/p&gt;&#xA;&lt;p&gt;However, the temperature would increase as you go down to the core, the source of the radioactive decay. It's 4-6k deg C in the core, so there will always be a spot inside the Earth which is toasty.&lt;/p&gt;&#xA;" OwnerUserId="21109" LastEditorUserId="6016" LastEditDate="2020-10-09T05:24:08.070" LastActivityDate="2020-10-09T05:24:08.070" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20294" PostTypeId="2" ParentId="20286" CreationDate="2020-10-07T19:51:23.640" Score="1" Body="&lt;p&gt;The west coast has had 25 years of preparation to plan for a possible 9.0 above richter scale event. Earthquakes in the industrialized world are not as substantial a deal despite the potential of infrastructure for damage. In the third world where building standards are poor, potential for catastrophic physical damage and deaths in the thousands is more problematic.&#xA;The most lethal recent quake in US was the 1964 Alaska &amp;quot;Good Friday&amp;quot; Quake which killed 140+ people. Japans 1995 quake killed six thousand!&#xA;But yes such a quake though possible is statiscally very unlikely. The biggest damage is structures built on land made of silt and sand.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-10-07T19:51:23.640" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20295" PostTypeId="2" ParentId="20283" CreationDate="2020-10-07T20:08:26.913" Score="-3" Body="&lt;p&gt;Humidity or recent rain plays a huge difference in air pollution. Seattle has less air pollution, because the effect of heavy rain and water accumulating on particles 'wash&amp;quot; the air. In hotter, drier Los Angeles the pollution stays in the air longer because there's less moisture to weigh it down. Mold, spores, dust and allergens do thrive in humidity but those aren't Pollutants in the classical industrial sense.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-10-07T20:08:26.913" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20296" PostTypeId="2" ParentId="20193" CreationDate="2020-10-07T21:00:03.190" Score="-2" Body="&lt;p&gt;There's No real evidence Biochar helps to sequester co2. Turning bioenergy crops into buried charcoal to sequester carbon does not work.&#xA;The biofuels ‘scam’ has already proven to be a dud. From corn to ethanol, algae experiments, etc and tropical crop related fuels. All they do is speed up deforestation and peatland destruction, deplete water and soil for agricultural sustained fuel production, and increased the use of farm-chemicals to meet quotas. Above all, it has generated  land grab, land conflicts, human rights abuses, labour abuses, starvation and food insecurity.&#xA;Worse Biochar according to research is a notorious oxygen sink.&#xA;&lt;a href=&quot;https://www.permaculturenews.org/2010/11/18/beware-the-biochar-initiative/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.permaculturenews.org/2010/11/18/beware-the-biochar-initiative/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastEditorUserId="21028" LastEditDate="2020-10-08T06:51:13.713" LastActivityDate="2020-10-08T06:51:13.713" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20297" PostTypeId="2" ParentId="20286" CreationDate="2020-10-08T03:04:53.553" Score="1" Body="&lt;p&gt;If you need a plausible west coast disaster, consider a fraction km meteor about 1500 km off shore.  This would do two things:&lt;/p&gt;&#xA;&lt;p&gt;A:  The Tsunami would hit most of the coast over a span of 4-6 hours.&lt;/p&gt;&#xA;&lt;p&gt;B:  It would rain sea water initially from the splash,killing a lot of vegetation.&lt;/p&gt;&#xA;&lt;p&gt;C:  It would wreck (or at least sharply reduce) crops throughout the northern hemisphere for a year or two. No one would have the resources to help the coastal victims.&lt;/p&gt;&#xA;&lt;p&gt;Note:  You may want to check out the worldbuilding SE for more of this kind of thing.&lt;/p&gt;&#xA;" OwnerUserId="13145" LastEditorUserId="13145" LastEditDate="2021-03-18T20:54:00.207" LastActivityDate="2021-03-18T20:54:00.207" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20299" PostTypeId="2" ParentId="20226" CreationDate="2020-10-08T07:52:19.830" Score="3" Body="&lt;p&gt;High pressures and low pressures at any height do not exist in isolation.  Had to remind myself a lot of this (so anyone feel free to correct), but the first thing worth highlighting is that the Bermuda High is a warm core high pressure and so extends a great depth through the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;This image is a fairly typical cross section of the atmosphere at 35 North in June:&lt;br /&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/9nOu5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9nOu5.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;sub&gt;&lt;sup&gt;Source: &lt;a href=&quot;https://psl.noaa.gov/data/gridded/data.ncep.reanalysis.derived.pressure.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCEP/NCAR Reanalysis Monthly Means&lt;/a&gt;&lt;/sup&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;The left of the two dashed lines is the center of the Bermuda High\Ridge.  Note how it it is very upright and strong through a large height... so the winds at low levels tend to be aligned to the winds at higher levels.  The high at each level has the same cause... being a favored area for the consistent sinking air caused by the Hadley Circulation [i.e. the necessity of poleward moving air to return to the Equator once it reaches certain velocities]&lt;/p&gt;&#xA;&lt;p&gt;On the other hand the blue trough\low (the dashed line further to the right) is tilted.  This is the typical structure of midlatitude cyclones (i.e. cold core lows).  The starting upper level feature causes the surface low to develop ahead of it (downstream) because the air moving out of the upper trough sparks rising motion below it due to divergence\positive vorticity advection increasing with height.&lt;/p&gt;&#xA;&lt;p&gt;The result (in the NH) is there will tend to be northwesterly winds at the ground locations &lt;a href=&quot;http://www.atmo.arizona.edu/students/courselinks/fall12/atmo336/lectures/sec1/cyclogenesis1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;near where the axis of the trough is passing over (and so southwest of the surface low\northeast of the surface high)&lt;/a&gt;.  Such northwesterly winds will tend to bring cooler air and lower relative humidities in most places, but it just how cold or dry the air will be depends upon the source region of the airmass the northwest winds are blowing in (which itself relates in large part back to the strength and larger history of the trough itself).&lt;/p&gt;&#xA;&lt;p&gt;Overall, fundamental cause of connections between motion\pressures at different atmospheric heights is the fact mass continuity must occur (if air rises, it must be replaced, and it must eventually sink somewhere else to maintain the weight-density to prevent continuing mass buildup/loss), and works out to clearer relationships such as &lt;a href=&quot;https://www.youtube.com/watch?v=oFjdvoTIZpw&quot; rel=&quot;nofollow noreferrer&quot;&gt;thermal wind&lt;/a&gt; (the reality that different winds at different height levels is a direct consequence\identity of temperature advection in the layer between the levels) and the fact the two main terms that cause vertical motion in the &lt;a href=&quot;http://williamsgj.people.cofc.edu/qg_theory_prediction.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;quasigeostrophic approximation&lt;/a&gt; are differential vorticity advection with height (i.e. different spin changes at different levels causes vertical movement) and maxima of temperature advection below (plus two other terms on friction and external heat).&lt;/p&gt;&#xA;&lt;p&gt;In a sense, the fact pressure at one elevation induces changes\motion in another elevation maybe shouldn't seem any less weird than the fact that a low-level low pressure system can affect the wind and weather hundreds of miles away from it horizontally.  This isn't &lt;a href=&quot;https://en.wikipedia.org/wiki/Action_at_a_distance&quot; rel=&quot;nofollow noreferrer&quot;&gt;spooky action at a distance&lt;/a&gt;, this is a continuous fluid where changes to one part of it causes impacts on another part.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2020-10-08T08:57:20.583" LastActivityDate="2020-10-08T08:57:20.583" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="20301" PostTypeId="2" ParentId="20193" CreationDate="2020-10-08T15:26:48.617" Score="1" Body="&lt;p&gt;The effects of biochar burial in California would be so minuscule they might be a net negative once you include the CO2 production of the labor involved. Biochar is a very labor intensive process. Consider carbon in fossil fuels was accumulated of millions of years of what is essentially the same process, even industrializing the process will still take comparable amounts of time to resequester that carbon using what is basically the same method. keep in mind fire is a normal part of many of these environmental cycles they are bad because humans kept preventing the normal fire cycles allowing fuels to build up for decades. Normally that fuel would be cleared by the natural fire cycles. Drought is a trigger not the cause.&lt;/p&gt;&#xA;&lt;p&gt;Large impact estimates assume we would have to be converting land to biochar production, which has many many downsides and still would not be very effective.&lt;/p&gt;&#xA;&lt;p&gt;It can be particularly confusing since &amp;quot;&lt;strong&gt;Bio-char&lt;/strong&gt;&amp;quot; can mean two different things, the most touted use of biochar (fertilizer) will have no real carbon sequestration effect but can be a way to offset industrial fertilizers. Burial would sequester some carbon, but would also deplete soils and biodiversity. You have to check and see which use of biochar a source is referring to.&lt;/p&gt;&#xA;&lt;p&gt;A better idea would be to burn the material as fuel, instead of fossil fuels, which would at least be carbon neutral.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nrdc.org/sites/default/files/biochar_paper.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2020-10-08T15:26:48.617" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20302" PostTypeId="2" ParentId="20250" CreationDate="2020-10-08T17:52:59.140" Score="3" Body="&lt;p&gt;I don't want to answer your question explicitly because it will ruin your education. Instead, I will guide you by asking three questions:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Where on the Skew-T are you?&lt;/li&gt;&#xA;&lt;li&gt;Where on the Skew-T do you want to go?&lt;/li&gt;&#xA;&lt;li&gt;What type of process do you want to undergo to get there? If it is dry and adiabatic, follow the dry adiabat (&lt;span class=&quot;math-container&quot;&gt;$\theta=T\left(\frac{P_0}{P}\right)^{\frac{R_d}{c_p}}$&lt;/span&gt;)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;I recommend drawing the process out. Does the result make sense?&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-10-08T17:52:59.140" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20303" PostTypeId="1" CreationDate="2020-10-09T04:34:21.897" Score="1" ViewCount="50" Body="&lt;p&gt;The RMM values are sometimes quite different. Can I average the values of RMM1 and RMM2 and use it as an index for MJO?&lt;/p&gt;&#xA;" OwnerUserId="21195" LastActivityDate="2020-10-09T16:00:08.090" Title="Can I average the two RMM values?" Tags="|meteorology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20304" PostTypeId="1" CreationDate="2020-10-09T08:18:26.700" Score="1" ViewCount="59" Body="&lt;p&gt;I'm a maize farmer and I'm almost ready for harvest.&lt;/p&gt;&#xA;&lt;p&gt;I'm planning to store my harvest for some time.&lt;/p&gt;&#xA;&lt;p&gt;Below are my questions:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;How long can I store my harvest?&lt;/li&gt;&#xA;&lt;li&gt;Can I sun dry my harvest with husk and kernel intact?&lt;/li&gt;&#xA;&lt;li&gt;Can I store this sun-dried harvest with husk and kernel intact?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="21200" LastActivityDate="2020-10-10T15:23:38.787" Title="Can we store maize along with husk and kernal?" Tags="|agriculture|plant|" AnswerCount="1" CommentCount="4" ClosedDate="2020-10-11T17:22:08.670" ContentLicense="CC BY-SA 4.0" />
  <row Id="20305" PostTypeId="2" ParentId="20303" CreationDate="2020-10-09T16:00:08.090" Score="1" Body="&lt;p&gt;&lt;strong&gt;CAN&lt;/strong&gt; you? Sure, nobody on here is stopping you.&lt;/p&gt;&#xA;&lt;p&gt;Is it meaningful? Not really.&lt;/p&gt;&#xA;&lt;p&gt;The RMM indices are two separate metrics corresponding to the phase (interpretable using a phase space diagram)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bscgl.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bscgl.png&quot; alt=&quot;MJO Phase Space Diagram&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(Example from &lt;a href=&quot;https://www.cpc.ncep.noaa.gov/products/precip/CWlink/MJO/forca.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;CPC&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;If you want a more meaningful way to interpret the MJO, you can try &lt;span class=&quot;math-container&quot;&gt;$$\sqrt{RMM_1^2+RMM_2^2}$$&lt;/span&gt; which should be the strength of the MJO, or the angle between &lt;span class=&quot;math-container&quot;&gt;$RMM_1$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$RMM_2$&lt;/span&gt; (probably using something like &lt;code&gt;atan2&lt;/code&gt; in your preferred programming language.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-10-09T16:00:08.090" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20306" PostTypeId="1" AcceptedAnswerId="20320" CreationDate="2020-10-09T18:58:30.457" Score="5" ViewCount="495" Body="&lt;p&gt;As I understand it, radioactive dating measures time by what portion of a radioactive isotope has decayed. Weren't all the natural radioactive isotopes created during the formation of the solar system? So how does radioactive dating age a specific rock, instead of just the number of years since the formation of the solar system?&lt;/p&gt;&#xA;" OwnerUserId="21203" LastActivityDate="2020-10-12T14:34:47.897" Title="Why does radioactive dating work on specific rocks?" Tags="|rocks|radioactivity|dating|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20308" PostTypeId="2" ParentId="20306" CreationDate="2020-10-09T20:04:03.713" Score="4" Body="&lt;p&gt;There are other, mostly chemical processes which alter the isotope ratios. Isotope dating uses a combination of them. This is why it can not be used always, for any radioactive isotopes, only in special circumstances. It also requires very sensitive measurements (below in the second example, close to induvidually count lead atoms in microscopic zircon crystals).&lt;/p&gt;&#xA;&lt;p&gt;For example, in carbon dating, C14 is continuously generated in the atmosphere due to the cosmic radiation, and builds in the biosphere, where it decays. If a plant stops accumulating carbon ( = it dies), its C14 ratio starts to decay.&lt;/p&gt;&#xA;&lt;p&gt;Another example, this time about isotopes which were created really with the Solar System. The mineral zircon (&lt;span class=&quot;math-container&quot;&gt;$\rm{ZrSiO_4}$&lt;/span&gt;) accumulates uranium and thorium atoms in it crystal structure, but strongly rejects lead. This rejection can happen as it freezes. After it is solid, the lead atoms created by U/Th decay do not go away any more. Thus, all the lead in the zircon crystals of the soil of Moon, were created since it frozen. This makes possible to know, when did that zircon solidify (&lt;span class=&quot;math-container&quot;&gt;$\approx$&lt;/span&gt; when formed the crust of the Moon).&lt;/p&gt;&#xA;" OwnerUserId="6016" LastEditorUserId="6016" LastEditDate="2020-10-10T13:54:42.147" LastActivityDate="2020-10-10T13:54:42.147" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20309" PostTypeId="2" ParentId="20306" CreationDate="2020-10-10T07:01:59.893" Score="2" Body="&lt;p&gt;Radioactive dating works on specific isotopes we use for specific time frames.&#xA;Rubidium–strontium dating methods (because this substance has a half life of 50 billion years) to date extremely old geological samples as well as space samples like lunar rocks.&lt;/p&gt;&#xA;&lt;p&gt;Another issue is the quantity of synthetic isotopes in varying samples. Alot of these isotopes do not occur in nature or don't occur in any sufficient amount capable of being used. Thus the only sources are manmade radioactive isotopes; such as the atomic bomb blasts such as Plutonium-238, Americium-241, etc, thus any high concentration found in an artifact or rock/soil is indicitive of atomic tests, steel/iron contaminated with these nuclides are a tell tale sign of any steel/alloy made after 1945. radioactive trace elements in teeth, bones and remains also let us know if a person even deceased was born Before or after Post WWII.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-10-10T07:01:59.893" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20310" PostTypeId="2" ParentId="20304" CreationDate="2020-10-10T15:23:38.787" Score="3" Body="&lt;p&gt;For the (1) you can store your whole maize for 8 - 12 years or 18 - 36 months if the maize is ground or chopped. Moreover the less moisture the maize has the more it can be stored. If you want to store your harvest for a long period of time then the maximum moisture  percentage is 13.5%.&lt;/p&gt;&#xA;" OwnerUserId="21202" LastActivityDate="2020-10-10T15:23:38.787" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20311" PostTypeId="2" ParentId="10289" CreationDate="2020-10-10T18:25:31.150" Score="0" Body="&lt;p&gt;There's no reliable evidence indicating hydroponics are less nutritious than soil grown crops. Because organic and inorganic techniques are applicable for hydroponics, any attempt to dismiss nutritional value requires analysis of the individual plant and the methods grown. Second Hydroponics isn't widely adopted agricultural method; it is however adopted where soil quality or outdoor temperature do not permit conventional crops desired from being grown; so ask what's the nutritional quality of a crop they never had to begin with.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-10-10T18:25:31.150" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20312" PostTypeId="2" ParentId="7054" CreationDate="2020-10-10T18:26:39.310" Score="2" Body="&lt;p&gt;There's No way to ascertain the level of soil reclamation since the 1930's the Soil Conservation service keeps track which I assume you can learn online if they have their data. Agronomic libraries May keep track of it. For one keeping tabs on something that affected over 200 million acres is spotty at best. The dust bowl occurred in six states, Texas, Oklahoma, New Mexico, Colorado, Nebraska and Kansas.  In environments dominated by a mild or temperate climate, it takes roughly 200-400 years to form half an inch of top soil. in wet tropical areas soil formation is substantially faster, it takes 200 years However tropical plants gobble up nutrients at record pace. It's been 80 years since the dust bowl, so far top soil hasn't regenerated at a recognizable rate. We use fertilizers to keep the soil productive.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-10-10T18:26:39.310" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20313" PostTypeId="1" CreationDate="2020-10-11T14:08:35.220" Score="1" ViewCount="230" Body="&lt;p&gt;I understand that from the hypsometric equation, in a cold core low the pressure gradient must increase with height, because in the center the isobars will be closer together:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5pKlW.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5pKlW.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;sub&gt;&lt;sup&gt;quente = hot, frio = cold&lt;/sup&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;What I don't understand is why in practice the low slopes towards the cold air with height:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4Meyz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4Meyz.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Also, I wonder how I can show mathematically (I guess from the thermal wind relationship + the hypsometric equation?), that in a cold core low, the wind must increase with height.&lt;/p&gt;&#xA;" OwnerUserId="20538" LastEditorUserId="6298" LastEditDate="2020-10-12T11:06:06.860" LastActivityDate="2020-10-12T15:38:17.063" Title="Why do cold-core lows slope towards the cold air with heigth? How to show mathematically that wind intensifies with height in this case?" Tags="|meteorology|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="20315" PostTypeId="2" ParentId="19655" CreationDate="2020-10-11T23:26:58.093" Score="1" Body="&lt;p&gt;If I understood the question right:&#xA;&lt;a href=&quot;https://code.mpimet.mpg.de/projects/cdo/embedded/index.html#x1-6630002.12.10&quot; rel=&quot;nofollow noreferrer&quot;&gt;CDO&lt;/a&gt; can interpolate from model level to height level with the operator&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;ml2hl infile.nc outfile.nc&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;additionally, for the lower atmospheric levels, you can add an extrapolation option.&#xA;BUT I don't recommend it since its extrapolation performance is questionable.&lt;/p&gt;&#xA;" OwnerUserId="20685" LastActivityDate="2020-10-11T23:26:58.093" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20317" PostTypeId="1" CreationDate="2020-10-12T03:34:01.517" Score="1" ViewCount="1415" Body="&lt;p&gt;I've looked this up as best as I could and couldn't find a clear answer. I've seen for example articles on the age of several rivers as being the oldest ones, but nothing regarding the opposite. Could you enlighten this for me?&lt;/p&gt;&#xA;" OwnerUserId="21211" LastActivityDate="2020-10-12T03:34:01.517" Title="How many years does it take for rivers to form?" Tags="|geology|rivers|age|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20318" PostTypeId="1" CreationDate="2020-10-12T08:32:35.367" Score="1" ViewCount="45" Body="&lt;p&gt;I'm collecting examples and inspiration of how existing software products or applications of any kind - non-profit or commercial - &lt;em&gt;directly&lt;/em&gt; help solving or preventing environmental problems like GHG emissions, deforestation, environmental degradation, pollution, resource depletion and others.&#xA;Of course the &lt;em&gt;directly&lt;/em&gt; part is very debatable, so here are some good examples of direct and clear impact I have until now:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;AI that detects sounds of chainsaw and monitors on-site deforestation (Rainforest Connection (RFCx))&lt;/li&gt;&#xA;&lt;li&gt;web platform that allows people to find food/meals in their city to buy that would be otherwise get thrown away (by restaurants, hotels, supermarkets - Too Good To Go&lt;/li&gt;&#xA;&lt;li&gt;optimising software libraries to be significantly smaller in size and thus make servers delivering them to have smaller carbon footprint (one unspecified Wordpress plugin)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="21213" LastActivityDate="2020-10-12T08:32:35.367" Title="What are good examples of how software helps solving today's environmental problems?" Tags="|environmental-protection|pollution|software|emissions|deforestation|" AnswerCount="0" CommentCount="4" ClosedDate="2020-10-13T07:27:33.297" ContentLicense="CC BY-SA 4.0" />
  <row Id="20319" PostTypeId="2" ParentId="3115" CreationDate="2020-10-12T09:23:41.390" Score="1" Body="&lt;p&gt;Chile has sedimentary deposits (gravels) about 12 Ma, in Atacama desert.&lt;/p&gt;&#xA;" OwnerUserId="21214" LastActivityDate="2020-10-12T09:23:41.390" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20320" PostTypeId="2" ParentId="20306" CreationDate="2020-10-12T14:34:47.897" Score="3" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Weren't all the natural radioactive isotopes created during the formation of the solar system?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The half life of carbon 14 is 5730 years, orders of magnitude less than the age of the solar system. Carbon 14 is constantly being created in the upper atmosphere by neutron bombardment of nitrogen 14. On the other hand, the other isotopes used in radioactive dating were created in the end stages of the life of a star, well before the solar system formed. The formation of the solar system did not create radioactive isotopes.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;So how does radioactive dating age a specific rock, instead of just the number of years since the formation of the solar system?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Carbon dating is perhaps the easiest to understand because this technique only looks at the ratio of carbon 14 to the stable isotopes of carbon. Plants take up carbon 14, along with carbon 12 and carbon 13, as they grow. Herbivores eat plants, and carnivores eat herbivore. The carbon 14 decays, leaving less and less of it as time passes.&lt;/p&gt;&#xA;&lt;p&gt;One problem with carbon dating is that the amount of carbon 14 in the atmosphere is not constant. Fortunately, there are trees that are almost 5000 years old; the varying amounts carbon 14 captured in their rings provides a direct calibration. Humans have used wood for construction for a long, long time, enabling calibrations to go back even further in time. Even older chunks of wood enable calibrations to go back 50000 years.&lt;/p&gt;&#xA;&lt;p&gt;Another form of radioactive dating is uranium-lead dating. This relies on the very different chemistries of uranium and lead. Lead does not combine chemically nearly as readily as does uranium with other elements. Uranium's chemistry is similar to that of zirconium, enabling uranium to replace zirconium in zircons. Lead is instead chemically rejected when zircons form. This means zircons have essentially no lead content when they form. The lead content in a zircon indicates how long ago the zircon formed.&lt;/p&gt;&#xA;&lt;p&gt;Other forms of radioactive dating rely on similar concepts. The different chemistries of parent and daughter isotopes is key in many of those techniques.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-10-12T14:34:47.897" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20321" PostTypeId="2" ParentId="20313" CreationDate="2020-10-12T15:38:17.063" Score="1" Body="&lt;p&gt;I've managed to show why wind speed increases with height in a cold core low, as follows. Considering low is in the Southern Hemisphere, the wind blows clockwise around the low. In natural coordinates, the normal vector points outwards. Since the center is colder than the surroundings, we have&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ \frac{\partial T}{\partial n}&amp;gt; 0 $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;from the thermal wind relationship,&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial  V_g}{\partial ln p}\boldsymbol{\widehat{t}}= \frac{-R}{f}\boldsymbol{\widehat{k}} \times\nabla_p{T}=\frac{-R}{f}\boldsymbol{\widehat{k}} \times\frac{\partial T}{\partial n}\boldsymbol{\widehat{n}}=\frac{R}{f}\frac{\partial T}{\partial n}\boldsymbol{\widehat{t}} $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where &lt;span class=&quot;math-container&quot;&gt;$\boldsymbol{\widehat{t}}$&lt;/span&gt;,&lt;span class=&quot;math-container&quot;&gt;$\boldsymbol{\widehat{n}}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$ \boldsymbol{\widehat{k}}$&lt;/span&gt; are the tangent, normal (in the horizontal plane) and vertical unit vectors.&lt;/p&gt;&#xA;&lt;p&gt;Since &lt;span class=&quot;math-container&quot;&gt;$ f &amp;lt; 0$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$ \frac{\partial T}{\partial n} &amp;gt; 0 $&lt;/span&gt;, we have &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial  V_g}{\partial ln p} &amp;lt; 0$&lt;/span&gt;, which implies &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial  V_g}{\partial z} &amp;gt; 0$&lt;/span&gt;, i.e., wind intensifies with height in a cold low.&lt;/p&gt;&#xA;&lt;p&gt;I still have not understood why the low is displaced towards cold air with height. Since the wind intensifies with height, I would expect the low to be further ahead at higher levels than at the surface.&lt;/p&gt;&#xA;" OwnerUserId="20538" LastActivityDate="2020-10-12T15:38:17.063" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20322" PostTypeId="2" ParentId="19655" CreationDate="2020-10-12T15:51:31.980" Score="1" Body="&lt;p&gt;I have two solutions.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Use &lt;a href=&quot;https://unidata.github.io/MetPy/latest/api/generated/metpy.calc.geopotential_to_height.html?highlight=height#metpy.calc.geopotential_to_height&quot; rel=&quot;nofollow noreferrer&quot;&gt;MetPy&lt;/a&gt; to calculate the height from the geopotential height.&lt;/li&gt;&#xA;&lt;li&gt;Use the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hypsometric_equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;hypsometric equation&lt;/a&gt;, averaging the temperature below the level.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-10-12T15:51:31.980" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20323" PostTypeId="2" ParentId="19050" CreationDate="2020-10-12T17:53:18.773" Score="1" Body="&lt;p&gt;aWhere Inc. &lt;a href=&quot;http://www.awhere.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;www.awhere.com&lt;/a&gt;   provides daily min and max temperature, precip, solar, wind for the agricultural earth (basically 60S-60N) at a resolution of 5 arc min or about 9km at the equator (1/12 degree)&lt;/p&gt;&#xA;" OwnerUserId="21216" LastActivityDate="2020-10-12T17:53:18.773" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20325" PostTypeId="1" CreationDate="2020-10-13T10:42:10.883" Score="3" ViewCount="757" Body="&lt;p&gt;I'm tidying my citations for my thesis, and I'm facing the task of sorting out the references for the IPCC reports (all of which have &lt;strong&gt;very&lt;/strong&gt; long lists of authors).&lt;/p&gt;&#xA;&lt;p&gt;Does anybody know where there are any existing online .bib files or similar for these references? I'd really prefer to avoid adding them all manually if I can help it. For some reason the IPCC doesn't seem to do this as standard, which seems kind of odd.&lt;/p&gt;&#xA;&lt;p&gt;Edit. OK I clearly didn't describe this very well. I'm after the references for chapters within the reports (as many as I can) not the references for information cited in the chapters. So AR5 WG1 CH1, Ch2 etc. etc.&lt;/p&gt;&#xA;" OwnerUserId="18621" LastEditorUserId="2958" LastEditDate="2021-04-25T16:05:31.610" LastActivityDate="2021-04-25T16:05:31.610" Title="IPCC digital references" Tags="|climate-change|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20326" PostTypeId="2" ParentId="20325" CreationDate="2020-10-13T11:48:26.513" Score="-1" Body="&lt;p&gt;You can copy-paste your reference from the instructions written on the frontpage of each report. For example, copy-pasted from the 2014 report:&lt;/p&gt;&#xA;&lt;p&gt;Referencing this report IPCC,  2014:&lt;br /&gt;&#xA;Climate  Change  2014:  Synthesis  Report. Contribution  of  Working  Groups  I,  II  and  III  to  the  Fifth  Assessment  Report  of  the  Intergovernmental Panel on Climate Change [Core Writing Team, R.K. Pachauri and L.A. Meyer (eds.)]. IPCC, Geneva, Switzerland, 151 pp.&lt;/p&gt;&#xA;" OwnerUserId="4551" LastActivityDate="2020-10-13T11:48:26.513" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20327" PostTypeId="2" ParentId="20325" CreationDate="2020-10-13T14:56:06.607" Score="3" Body="&lt;p&gt;Some of the IPCC AR5 reports were written in LaTeX, some in MS Word. You will not be able to get the .bib files for those reports written using MS Word because Word does not use BibTeX.&lt;/p&gt;&#xA;&lt;p&gt;Working Group I did use LaTeX, and you can get the .bib files for their report, on a chapter by chapter basis, &lt;a href=&quot;http://www.climatechange2013.org/report/full-report/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Working Group II apparently used Word, but they have released a set of bibliographies in both .csv and .xml format. I used &amp;quot;apparently&amp;quot; because I am getting errors galore for any page under ipcc-wg2.org. Apparently IPCC Working Group II has not updated their subscription, and some expletive deleted online gambling company has bought rights to that domain.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2020-10-13T15:29:04.870" LastActivityDate="2020-10-13T15:29:04.870" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20332" PostTypeId="1" CreationDate="2020-10-14T13:06:49.697" Score="3" ViewCount="263" Body="&lt;p&gt;Every electrical device consumes electric energy and almost every one of them I can think of produces heat as a byproduct. This also applies on every kind of machine powered vehicle. Even our bodies produce a small amount of heat. Almost everything produces a small or high amount of heat. This only gets more and more with more people on this planet and continuing industrialization. Just think of all the giant production around the world and all the means of transportation - they all produce a massive amount of heat.&lt;/p&gt;&#xA;&lt;p&gt;If you put hundred cups of hot tea into one room the room temperature rises as the tea cools, right? This is heat transfer.&lt;/p&gt;&#xA;&lt;p&gt;I asked myself wether we would still have a negative effect on the climate even when we (could) reduce our carbon footprint down to zero today or not. We would still produce a lot of heat with almost everything we do.&lt;/p&gt;&#xA;&lt;p&gt;To what extent has heat production a negative effect on the climate compared to co2 emission?&lt;/p&gt;&#xA;&lt;p&gt;And why is heat production never payed attention to?&lt;/p&gt;&#xA;" OwnerUserId="21225" LastActivityDate="2020-10-15T19:39:41.160" Title="Would the climate still rise when we reduce our carbon footprint down to zero?" Tags="|climate-change|climate|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20333" PostTypeId="2" ParentId="20332" CreationDate="2020-10-14T14:50:12.170" Score="5" Body="&lt;p&gt;While I can't comment on whether the global temperature would still rise if humanity's carbon footprint were reduced to zero, I do know that the heat our machines produce would not contribute any net warming effect. The issue is not the amount of heat which is entering the atmosphere -- it's where and &lt;em&gt;when&lt;/em&gt; that heat came from.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Assuming that we are successful in reaching &lt;a href=&quot;https://web.stanford.edu/group/efmh/jacobson/Articles/I/100Pct-WWS-Papers.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;100% wind, water, and solar energy&lt;/a&gt;, the energy consumed at the end use would be from only seconds to at most a year ago:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Seconds: Solar power from photovoltaic panels is collected, converted to electricity, transmitted to the grid, and used almost instantaneously&lt;/li&gt;&#xA;&lt;li&gt;Hours to days: Wind is primarily generated by daily fluctuations in surface temperature caused by the sun&lt;/li&gt;&#xA;&lt;li&gt;Months: The water in rivers which power hydroelectric dams is generated by seasonal patterns in precipitation, which is a function of changes in solar intensity over the course of the year&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;In contrast, the energy we're using today from fossil fuels is tens to hundreds of millions of years old, containing energy harvested from the sun over a period of over a hundred million years&lt;/strong&gt; (&lt;a href=&quot;https://energyeducation.ca/encyclopedia/Oil_formation&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;The energy from wind, water, and solar sources is being added to our atmosphere anyway -- we just convert it into different forms to use it for other purposes in between its transit from the sun to the planet.&lt;/p&gt;&#xA;&lt;p&gt;By contrast, the energy from fossil fuels had been locked away, safely stored for 100 million years or more. Until we started drilling and mining, it was no longer having any significant impact on the planet.&lt;/p&gt;&#xA;&lt;p&gt;This also applies to the food we consume -- the energy that fruits and vegetables store is at most a year old -- for animal products, it's at most two to three years old.&lt;/p&gt;&#xA;" OwnerUserId="7741" LastEditorUserId="7741" LastEditDate="2020-10-15T16:33:14.963" LastActivityDate="2020-10-15T16:33:14.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20334" PostTypeId="2" ParentId="20332" CreationDate="2020-10-14T15:42:42.150" Score="-6" Body="&lt;p&gt;Uh yeah, slightly because a cessation of co2 emissions isn't removing the centuries worth of prior emissions, however that's a while from now. The temps been rising since 1750's before the industrial revolution. But CO2 on Earth has been steadily declining, we're in the midst of a coldhouse period and a carbon drought which is perpetual. When humanity unleashed fossil fuels they put Co2 back in the atmosphere, we've been regenerating the biosphere with carbon, the building block for life. More co2 means more bioproductivity. Greenhouse growers understood this decades ago&#xA;&lt;a href=&quot;https://i.stack.imgur.com/wHcLb.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wHcLb.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Even ocean life, contrary to popular claim the oceans get more acidic, in co2 enrichment, more carbon means more building blocks for shelled creatures. Experiments show bubbling more co2 means they creatures get Bigger.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/NugjB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NugjB.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-10-14T15:42:42.150" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20336" PostTypeId="1" CreationDate="2020-10-14T19:15:32.553" Score="3" ViewCount="103" Body="&lt;p&gt;MUNICH is the Model of Urban Network of Intersecting Canyons and Highways (MUNICH) (Kim et al., 2018) and VEIN is the Vehicular Emissions INventory model (Ibarra-Espinosa et al, 2018), an &lt;a href=&quot;https://atmoschem.github.io/vein/&quot; rel=&quot;nofollow noreferrer&quot;&gt;R package&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;VEIN estimates vehicular emissions at street level, generating useful inputs for the MUNICH model, however, some pre-processing is necessary. Therefore, the model &lt;a href=&quot;https://atmoschem.github.io/eixport/&quot; rel=&quot;nofollow noreferrer&quot;&gt;eixport&lt;/a&gt; was created to help in this processing.&lt;/p&gt;&#xA;&lt;p&gt;As a maintainer I receive many emails asking how to generate inputs for the MUNICH model&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Kim, Y., Wu, Y., Seigneur, C., and Roustan, Y.: Multi-scale modeling of urban air pollution: development and application of a Street-in-Grid model (v1.0) by coupling MUNICH (v1.0) and Polair3D (v1.8.1), Geosci. Model Dev., 11, 611-629, &lt;a href=&quot;https://doi.org/10.5194/gmd-11-611-2018&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.5194/gmd-11-611-2018&lt;/a&gt;, 2018.&lt;/li&gt;&#xA;&lt;li&gt;Ibarra-Espinosa, S., Ynoue, R., O'Sullivan, S., Pebesma, E., Andrade, M. D. F., and Osses, M.: VEIN v0.2.2: an R package for bottom–up vehicular emissions inventories, Geosci. Model Dev., 11, 2209–2229, &lt;a href=&quot;https://doi.org/10.5194/gmd-11-2209-2018&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.5194/gmd-11-2209-2018&lt;/a&gt;, 2018.&lt;/li&gt;&#xA;&lt;li&gt;Ibarra-Espinosa et al., (2018b). eixport: An R package to export emissions to atmospheric models. Journal of Open Source Software, 3(24), 607, &lt;a href=&quot;https://doi.org/10.21105/joss.00607&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.21105/joss.00607&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6489" LastEditorUserId="2470" LastEditDate="2021-04-22T10:44:43.533" LastActivityDate="2022-01-17T12:03:25.273" Title="How to generate inputs for the MUNICH model from the VEIN model" Tags="|air-pollution|air-quality|emissions|r|vein-r-package|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20337" PostTypeId="2" ParentId="20336" CreationDate="2020-10-14T19:15:32.553" Score="1" Body="&lt;p&gt;First, download a project with vein and estimate vehicular emissions.&#xA;Some projects are here: &lt;a href=&quot;https://atmoschem.github.io/vein/reference/get_project.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://atmoschem.github.io/vein/reference/get_project.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;library(vein)&#xA;get_project(directory = &amp;quot;awesomecity&amp;quot;)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Then open the file main.Rproj with Rstudio and source the file main.R&lt;/p&gt;&#xA;&lt;p&gt;Then, run the following code&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;library(data.table)&#xA;library(eixport)&#xA;library(sf)&#xA;#&amp;gt; Linking to GEOS 3.8.0, GDAL 3.0.4, PROJ 6.3.1&#xA;library(writexl)&#xA;library(vein)&#xA;library(units)&#xA;#&amp;gt; udunits system database from /usr/share/xml/udunits&#xA;# epsg 31983, projected UTM&#xA;co &amp;lt;- readRDS(&amp;quot;post/streets/CO.rds&amp;quot;)&#xA;st_crs(co)&#xA;#&amp;gt; Coordinate Reference System:&#xA;#&amp;gt;   User input: EPSG:31983 &#xA;#&amp;gt;   wkt:&#xA;#&amp;gt; PROJCS[&amp;quot;SIRGAS 2000 / UTM zone 23S&amp;quot;,&#xA;#&amp;gt;     GEOGCS[&amp;quot;SIRGAS 2000&amp;quot;,&#xA;#&amp;gt;         DATUM[&amp;quot;Sistema_de_Referencia_Geocentrico_para_las_AmericaS_2000&amp;quot;,&#xA;#&amp;gt;             SPHEROID[&amp;quot;GRS 1980&amp;quot;,6378137,298.257222101,&#xA;#&amp;gt;                 AUTHORITY[&amp;quot;EPSG&amp;quot;,&amp;quot;7019&amp;quot;]],&#xA;#&amp;gt;             TOWGS84[0,0,0,0,0,0,0],&#xA;#&amp;gt;             AUTHORITY[&amp;quot;EPSG&amp;quot;,&amp;quot;6674&amp;quot;]],&#xA;#&amp;gt;         PRIMEM[&amp;quot;Greenwich&amp;quot;,0,&#xA;#&amp;gt;             AUTHORITY[&amp;quot;EPSG&amp;quot;,&amp;quot;8901&amp;quot;]],&#xA;#&amp;gt;         UNIT[&amp;quot;degree&amp;quot;,0.0174532925199433,&#xA;#&amp;gt;             AUTHORITY[&amp;quot;EPSG&amp;quot;,&amp;quot;9122&amp;quot;]],&#xA;#&amp;gt;         AUTHORITY[&amp;quot;EPSG&amp;quot;,&amp;quot;4674&amp;quot;]],&#xA;#&amp;gt;     PROJECTION[&amp;quot;Transverse_Mercator&amp;quot;],&#xA;#&amp;gt;     PARAMETER[&amp;quot;latitude_of_origin&amp;quot;,0],&#xA;#&amp;gt;     PARAMETER[&amp;quot;central_meridian&amp;quot;,-45],&#xA;#&amp;gt;     PARAMETER[&amp;quot;scale_factor&amp;quot;,0.9996],&#xA;#&amp;gt;     PARAMETER[&amp;quot;false_easting&amp;quot;,500000],&#xA;#&amp;gt;     PARAMETER[&amp;quot;false_northing&amp;quot;,10000000],&#xA;#&amp;gt;     UNIT[&amp;quot;metre&amp;quot;,1,&#xA;#&amp;gt;         AUTHORITY[&amp;quot;EPSG&amp;quot;,&amp;quot;9001&amp;quot;]],&#xA;#&amp;gt;     AXIS[&amp;quot;Easting&amp;quot;,EAST],&#xA;#&amp;gt;     AXIS[&amp;quot;Northing&amp;quot;,NORTH],&#xA;#&amp;gt;     AUTHORITY[&amp;quot;EPSG&amp;quot;,&amp;quot;31983&amp;quot;]]&#xA;head(co, 1) # units g/h&#xA;#&amp;gt; Simple feature collection with 1 feature and 25 fields&#xA;#&amp;gt; geometry type:  LINESTRING&#xA;#&amp;gt; dimension:      XY&#xA;#&amp;gt; bbox:           xmin: 328001.4 ymin: 7391129 xmax: 328036.5 ymax: 7391204&#xA;#&amp;gt; projected CRS:  SIRGAS 2000 / UTM zone 23S&#xA;#&amp;gt;        id            V1             V2             V3             V4&#xA;#&amp;gt; 1 1 [1/h] 275.088 [g/h] 140.0241 [g/h] 84.63286 [g/h] 86.81989 [g/h]&#xA;#&amp;gt;               V5             V6             V7         V8             V9&#xA;#&amp;gt; 1 195.8425 [g/h] 680.7458 [g/h] 1423.767 [g/h] 1719 [g/h] 1723.265 [g/h]&#xA;#&amp;gt;              V10            V11            V12            V13          V14&#xA;#&amp;gt; 1 1748.996 [g/h] 1600.077 [g/h] 1448.586 [g/h] 1378.825 [g/h] 1551.5 [g/h]&#xA;#&amp;gt;              V15            V16            V17            V18            V19&#xA;#&amp;gt; 1 1556.648 [g/h] 1538.186 [g/h] 1698.133 [g/h] 1655.548 [g/h] 1601.138 [g/h]&#xA;#&amp;gt;              V20            V21            V22            V23            V24&#xA;#&amp;gt; 1 1398.703 [g/h] 941.4398 [g/h] 709.3241 [g/h] 581.2601 [g/h] 407.1127 [g/h]&#xA;#&amp;gt;                         geometry&#xA;#&amp;gt; 1 LINESTRING (328001.4 739120...&#xA;&#xA;# example of  polygon as buffer at center&#xA;st_bbox(co) %&amp;gt;%&#xA;  st_as_sfc() %&amp;gt;%&#xA;  st_centroid() %&amp;gt;%&#xA;  st_buffer(dist = 2000) -&amp;gt; polygon&#xA;&#xA;# if you have another polygon, read it&#xA;# polygon &amp;lt;- st_read(&amp;quot;/path/to/polygon.gpkg&amp;quot;)&#xA;&#xA;cob &amp;lt;- st_intersection(co, polygon)&#xA;#&amp;gt; Warning: attribute variables are assumed to be spatially constant throughout all&#xA;#&amp;gt; geometries&#xA;&#xA;# Remove ID&#xA;co$id &amp;lt;- NULL&#xA;&#xA;# split on vertex conserving mass&#xA;cos &amp;lt;- st_explode(cob)&#xA;#&amp;gt; Sum: 16542955.31&#xA;dim(cos)&#xA;#&amp;gt; [1] 372  27&#xA;# it adds length LKM and LKM2&#xA;# Should we remove streets shorter than 10 mts?&#xA;cos &amp;lt;- cos[as.numeric(cos$LKM2) &amp;gt; 10, ]&#xA;&#xA;# remove LKM and LKM2&#xA;cos&lt;span class=&quot;math-container&quot;&gt;$LKM &amp;lt;- cos$&lt;/span&gt;LKM2 &amp;lt;- NULL&#xA;&#xA;# We need to add units back, g/h&#xA;cos &amp;lt;- vein::Emissions(cos, time = &amp;quot;1/h&amp;quot;)&#xA;head(cos, 1)&#xA;#&amp;gt; Simple feature collection with 1 feature and 24 fields&#xA;#&amp;gt; geometry type:  LINESTRING&#xA;#&amp;gt; dimension:      XY&#xA;#&amp;gt; bbox:           xmin: 331916.3 ymin: 7385767 xmax: 331922.9 ymax: 7385775&#xA;#&amp;gt; projected CRS:  SIRGAS 2000 / UTM zone 23S&#xA;#&amp;gt;               V1             V2             V3             V4             V5&#xA;#&amp;gt; 1 59.38562 [g/h] 30.22821 [g/h] 18.27042 [g/h] 18.74256 [g/h] 42.27821 [g/h]&#xA;#&amp;gt;               V6             V7             V8             V9            V10&#xA;#&amp;gt; 1 146.9585 [g/h] 307.3609 [g/h] 371.0953 [g/h] 372.0159 [g/h] 377.5708 [g/h]&#xA;#&amp;gt;              V11            V12            V13            V14            V15&#xA;#&amp;gt; 1 345.4224 [g/h] 312.7188 [g/h] 297.6588 [g/h] 334.9356 [g/h] 336.0469 [g/h]&#xA;#&amp;gt;              V16            V17            V18            V19          V20&#xA;#&amp;gt; 1 332.0614 [g/h] 366.5907 [g/h] 357.3973 [g/h] 345.6514 [g/h] 301.95 [g/h]&#xA;#&amp;gt;              V21            V22            V23            V24&#xA;#&amp;gt; 1 203.2367 [g/h] 153.1279 [g/h] 125.4816 [g/h] 87.88691 [g/h]&#xA;#&amp;gt;                         geometry&#xA;#&amp;gt; 1 LINESTRING (331916.3 738577...&#xA;# now we transform for the REQUIRED UNITS FOR MUNICH&#xA;# ug/km/h&#xA;&#xA;# we have 24 hours in this case&#xA;hours &amp;lt;- paste0(&amp;quot;V&amp;quot;, 1:24)&#xA;&#xA;for (i in seq_along(hours)) {&#xA;  cos[[hours[i]]] &amp;lt;- set_units(cos[[hours[i]]], ug / h)&#xA;  cos[[hours[i]]] &amp;lt;- cos[[hours[i]]] / set_units(st_length(cos), km)&#xA;}&#xA;plot(cos[&amp;quot;V1&amp;quot;], axes = T)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/zQ2yO.png&quot; alt=&quot;&quot; /&gt;&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;etm &amp;lt;- to_munich(sdf = cos)&#xA;names(etm)&#xA;#&amp;gt; [1] &amp;quot;Emissions&amp;quot; &amp;quot;Street&amp;quot;&#xA;head(etm&lt;span class=&quot;math-container&quot;&gt;$Emissions, 1)&#xA;#&amp;gt;   i idbrin typo        xa        ya        xb        yb                   V1&#xA;#&amp;gt; 1 1      1    0 -46.64773 -23.62993 -46.64766 -23.63001 5462199660 [ug/h/km]&#xA;#&amp;gt;                     V2                   V3                   V4&#xA;#&amp;gt; 1 2780345076 [ug/h/km] 1680485867 [ug/h/km] 1723911918 [ug/h/km]&#xA;#&amp;gt;                     V5                    V6                    V7&#xA;#&amp;gt; 1 3888685780 [ug/h/km] 13517016236 [ug/h/km] 28270586844 [ug/h/km]&#xA;#&amp;gt;                      V8                    V9                   V10&#xA;#&amp;gt; 1 34132780053 [ug/h/km] 34217462106 [ug/h/km] 34728386913 [ug/h/km]&#xA;#&amp;gt;                     V11                   V12                   V13&#xA;#&amp;gt; 1 31771425772 [ug/h/km] 28763397272 [ug/h/km] 27378203813 [ug/h/km]&#xA;#&amp;gt;                     V14                   V15                   V16&#xA;#&amp;gt; 1 30806871891 [ug/h/km] 30909088139 [ug/h/km] 30542507720 [ug/h/km]&#xA;#&amp;gt;                     V17                   V18                   V19&#xA;#&amp;gt; 1 33718452534 [ug/h/km] 32872865695 [ug/h/km] 31792493506 [ug/h/km]&#xA;#&amp;gt;                     V20                   V21                   V22&#xA;#&amp;gt; 1 27772900557 [ug/h/km] 18693404826 [ug/h/km] 14084471885 [ug/h/km]&#xA;#&amp;gt;                     V23                  V24&#xA;#&amp;gt; 1 11541609851 [ug/h/km] 8083705065 [ug/h/km]&#xA;head(etm$&lt;/span&gt;Street, 1)&#xA;#&amp;gt;   i       length width height&#xA;#&amp;gt; 1 1 10.87211 [m]     0     30&#xA;&#xA;# to export to CSV which supports bit64&#xA;data.table::fwrite(&#xA;  etm&lt;span class=&quot;math-container&quot;&gt;$Emissions,&#xA;  paste0(basename(getwd()), &quot;_Emissions.csv&quot;)&#xA;)&#xA;data.table::fwrite(&#xA;  etm$&lt;/span&gt;Street,&#xA;  paste0(basename(getwd()), &amp;quot;_Streets.csv&amp;quot;)&#xA;)&#xA;&#xA;# to export to Excel&#xA;writexl::write_xlsx(&#xA;  x = etm&lt;span class=&quot;math-container&quot;&gt;$Emissions,&#xA;  path = paste0(basename(getwd()), &quot;_Emissions.xlsx&quot;)&#xA;)&#xA;writexl::write_xlsx(&#xA;  x = etm$&lt;/span&gt;Street,&#xA;  path = paste0(basename(getwd()), &amp;quot;_Streets.xlsx&amp;quot;)&#xA;)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;&lt;sup&gt;Created on 2020-10-14 by the &lt;a href=&quot;https://reprex.tidyverse.org&quot; rel=&quot;nofollow noreferrer&quot;&gt;reprex package&lt;/a&gt; (v0.3.0)&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="6489" LastEditorUserId="6489" LastEditDate="2020-10-14T19:38:51.053" LastActivityDate="2020-10-14T19:38:51.053" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20338" PostTypeId="5" CreationDate="2020-10-14T19:31:32.350" Score="0" Body="&lt;p&gt;This tag has been replaced by the &lt;code&gt;vein-r-package&lt;/code&gt; tag and should no longer be used.&lt;/p&gt;&#xA;" OwnerUserId="6489" LastEditorUserId="2470" LastEditDate="2021-04-22T10:50:40.040" LastActivityDate="2021-04-22T10:50:40.040" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20339" PostTypeId="4" CreationDate="2020-10-14T19:31:32.350" Score="0" Body="This tag has been replaced by the `vein-r-package` tag and should no longer be used." OwnerUserId="-1" LastEditorUserId="2470" LastEditDate="2021-04-22T10:50:40.040" LastActivityDate="2021-04-22T10:50:40.040" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20341" PostTypeId="2" ParentId="13373" CreationDate="2020-10-15T03:35:08.140" Score="2" Body="&lt;p&gt;I used the R package &lt;a href=&quot;https://atmoschem.github.io/eixport/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;eixport&lt;/a&gt; (Ibarra-Espinosa et al., 2018) to download EDGAR data (5 and spec voc 4.3.2) and then include several speciations for chemical mechanisms according to Carter (2015) and Lopez-Norena et al (2019).&lt;/p&gt;&#xA;&lt;p&gt;The functions to download EDGAR are commented. This means that you must download all NetCDF files before running &lt;a href=&quot;https://atmoschem.github.io/eixport/reference/chem_edgar.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;chem_edgar&lt;/a&gt;.&lt;/p&gt;&#xA;&#xA;&lt;pre&gt;&lt;code&gt;library(eixport)&#xA;library(rasterVis)&#xA;#&amp;gt; Loading required package: raster&#xA;#&amp;gt; Loading required package: sp&#xA;#&amp;gt; Loading required package: lattice&#xA;#&amp;gt; Loading required package: latticeExtra&#xA;library(cptcity)&#xA;# 1 Get EDGAR ####&#xA;# get_edgar(dataset = &amp;quot;v432_VOC_spec&amp;quot;,&#xA;#           destpath = &amp;quot;V50_432_AP/TOT/&amp;quot;,&#xA;#           sector = c( &amp;quot;TOTALS&amp;quot;),&#xA;#           type = &amp;quot;nc&amp;quot;,&#xA;#           year = 2012)&#xA;#&#xA;# get_edgar(dataset = &amp;quot;v50_AP&amp;quot;,&#xA;#           destpath = &amp;quot;V50_432_AP/TOT&amp;quot;,&#xA;#           sector = c( &amp;quot;TOTALS&amp;quot;),&#xA;#           type = &amp;quot;nc&amp;quot;,&#xA;#           year = 2014)&#xA;#&#xA;# get_edgar(dataset = &amp;quot;v432_VOC_spec&amp;quot;,&#xA;#           destpath = &amp;quot;V50_432_AP/TRO/&amp;quot;,&#xA;#           sector = c( &amp;quot;TRO&amp;quot;),&#xA;#           type = &amp;quot;nc&amp;quot;,&#xA;#           year = 2012, ask = F)&#xA;#&#xA;# get_edgar(dataset = &amp;quot;v50_AP&amp;quot;,&#xA;#           destpath = &amp;quot;V50_432_AP/TRO&amp;quot;,&#xA;#           sector = c( &amp;quot;TRO_RES&amp;quot;, &amp;quot;TRO_noRES&amp;quot;),&#xA;#           type = &amp;quot;nc&amp;quot;,&#xA;#           year = 2014)&#xA;#&#xA;# totals &amp;lt;- list.files(path = &amp;quot;V50_432_AP/TOT/&amp;quot;,&#xA;#                      full.names = TRUE,&#xA;#                      pattern = &amp;quot;.zip&amp;quot;)&#xA;# lapply(totals, unzip, exdir = &amp;quot;V50_432_AP/TOT//&amp;quot;)&#xA;#&#xA;#&#xA;# tros &amp;lt;- list.files(path = &amp;quot;V50_432_AP/TRO&amp;quot;,&#xA;#                      full.names = TRUE,&#xA;#                      pattern = &amp;quot;.zip&amp;quot;)&#xA;# lapply(tros, unzip, exdir = &amp;quot;V50_432_AP/TRO/&amp;quot;)&#xA;a &amp;lt;- chem_edgar(path = &amp;quot;EDGAR/V50_432_AP/TOT&amp;quot;, chem = &amp;quot;cbmz_mosaic&amp;quot;)&#xA;#&amp;gt; units:  kg m-2 s-1 &#xA;#&amp;gt; Detecting the following files:&#xA;#&amp;gt;                                                           lncs&#xA;#&amp;gt; voc1   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc1_2012.0.1x0.1.nc&#xA;#&amp;gt; voc2   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc2_2012.0.1x0.1.nc&#xA;#&amp;gt; voc3   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc3_2012.0.1x0.1.nc&#xA;#&amp;gt; voc4   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc4_2012.0.1x0.1.nc&#xA;#&amp;gt; voc5   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc5_2012.0.1x0.1.nc&#xA;#&amp;gt; voc6   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc6_2012.0.1x0.1.nc&#xA;#&amp;gt; voc7   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc7_2012.0.1x0.1.nc&#xA;#&amp;gt; voc8   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc8_2012.0.1x0.1.nc&#xA;#&amp;gt; voc9   EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc9_2012.0.1x0.1.nc&#xA;#&amp;gt; voc10 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc10_2012.0.1x0.1.nc&#xA;#&amp;gt; voc11 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc11_2012.0.1x0.1.nc&#xA;#&amp;gt; voc12 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc12_2012.0.1x0.1.nc&#xA;#&amp;gt; voc13 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc13_2012.0.1x0.1.nc&#xA;#&amp;gt; voc14 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc14_2012.0.1x0.1.nc&#xA;#&amp;gt; voc15 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc15_2012.0.1x0.1.nc&#xA;#&amp;gt; voc16 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc16_2012.0.1x0.1.nc&#xA;#&amp;gt; voc17 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc17_2012.0.1x0.1.nc&#xA;#&amp;gt; voc18 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc18_2012.0.1x0.1.nc&#xA;#&amp;gt; voc19 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc19_2012.0.1x0.1.nc&#xA;#&amp;gt; voc20 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc20_2012.0.1x0.1.nc&#xA;#&amp;gt; vpc21 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc21_2012.0.1x0.1.nc&#xA;#&amp;gt; voc22 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc22_2012.0.1x0.1.nc&#xA;#&amp;gt; voc23 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc23_2012.0.1x0.1.nc&#xA;#&amp;gt; voc24 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc24_2012.0.1x0.1.nc&#xA;#&amp;gt; voc25 EDGAR/V50_432_AP/TOT/v432_VOC_spec_voc25_2012.0.1x0.1.nc&#xA;#&amp;gt; co                 EDGAR/V50_432_AP/TOT/v50_CO_2014.0.1x0.1.nc&#xA;#&amp;gt; nox               EDGAR/V50_432_AP/TOT/v50_NOx_2014.0.1x0.1.nc&#xA;#&amp;gt; nmvoc           EDGAR/V50_432_AP/TOT/v50_NMVOC_2014.0.1x0.1.nc&#xA;#&amp;gt; so2               EDGAR/V50_432_AP/TOT/v50_SO2_2014.0.1x0.1.nc&#xA;#&amp;gt; nh3               EDGAR/V50_432_AP/TOT/v50_NH3_2014.0.1x0.1.nc&#xA;#&amp;gt; pm10             EDGAR/V50_432_AP/TOT/v50_PM10_2014.0.1x0.1.nc&#xA;#&amp;gt; pm25            EDGAR/V50_432_AP/TOT/v50_PM2.5_2014.0.1x0.1.nc&#xA;#&amp;gt; bc                 EDGAR/V50_432_AP/TOT/v50_BC_2014.0.1x0.1.nc&#xA;#&amp;gt; oc                 EDGAR/V50_432_AP/TOT/v50_OC_2014.0.1x0.1.nc&#xA;#&amp;gt; EDGAR data: voc1  voc2  voc3  voc4  voc5  voc6  voc7  voc8  voc9  voc10  voc11  voc12  voc13  voc14  voc15  voc16  voc17  voc18  voc19  voc20  voc21  voc22  voc23  voc24  voc25  co  nox  nmvoc  so2  nh3  pm10  pm2.5  bc  oc  units of gases: mol/km2/h&#xA;#&amp;gt; units of aerosols: ug/m2/s&#xA;# just for the plot, replaces 0 with NA&#xA;&#xA;a&lt;span class=&quot;math-container&quot;&gt;$E_CO[] &amp;lt;- ifelse(a$&lt;/span&gt;E_CO[] &amp;lt;= 0, NA, a&lt;span class=&quot;math-container&quot;&gt;$E_CO[])&#xA;colors &amp;lt;- c(cpt(pal = &quot;mpl_viridis&quot;, rev = F, n = 200), &#xA;            cpt(n = 100, rev = T))&#xA;levelplot(a$&lt;/span&gt;E_CO, &#xA;          col.regions = colors,&#xA;          zscaleLog = T)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/I7CZr.png&quot; alt=&quot;&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;Created on 2020-10-15 by the &lt;a href=&quot;https://reprex.tidyverse.org&quot; rel=&quot;nofollow noreferrer&quot;&gt;reprex package&lt;/a&gt; (v0.3.0)&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;Carter, W. P. (2015). Development of a database for chemical mechanism assignments for volatile organic emissions. Journal of the Air &amp;amp; Waste Management Association, 65(10), 1171-1184.&lt;/p&gt;&#xA;&lt;p&gt;Lopez-Norena, Ana and Fernandez, Rafael &amp;amp; Puliafito, SALVADOR. (2019). ESPECIACION DE INVENTARIOS DE EMISIONES DE AEROSOLES Y COMPUESTOS ORGANICOS VOLATILES PARA EL MODELO WRF-CHEM, APLICADO A LOS ESQUEMAS RADM-2, CBM-Z Y MOZART&lt;/p&gt;&#xA;&lt;p&gt;Ibarra-Espinosa et al., (2018). eixport: An R package to export emissions to atmospheric models. Journal of Open Source Software, 3(24), 607, &lt;a href=&quot;https://doi.org/10.21105/joss.00607&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.21105/joss.00607&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6489" LastActivityDate="2020-10-15T03:35:08.140" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20343" PostTypeId="1" CreationDate="2020-10-16T18:39:20.050" Score="1" ViewCount="45" Body="&lt;p&gt;For a long time, I've been trying to use Stellarium (simulation) and many visualizations and animations in order to get a good idea of how the Sun and Moon move across the sky, as seen by a human from the surface of Earth.&lt;/p&gt;&#xA;&lt;p&gt;It's surprisingly difficult to grasp this, at least for me.&lt;/p&gt;&#xA;&lt;p&gt;It &lt;strong&gt;seems&lt;/strong&gt; to me that the Sun always &amp;quot;rises&amp;quot; in the &amp;quot;East&amp;quot;, goes slowly up to &amp;quot;above our heads&amp;quot;, and then sets to the &amp;quot;West&amp;quot; in the same manner, making a kind of half-circular path. After that, after some unknown time, the Moon kind of &amp;quot;follows&amp;quot; the Sun in this (more or less) exact path, also coming up from the East and &amp;quot;setting&amp;quot; in the West.&lt;/p&gt;&#xA;&lt;p&gt;The fact that the Moon is orbiting around Earth, and Earth orbits around the Sun, and yet they move like this, makes no sense to my brain. It seems like the described path would only be true for the Sun, or the Moon, but not both.&lt;/p&gt;&#xA;&lt;p&gt;And is it always (roughly) the same? Or does this vary depending on where you stand on Earth, and what date/year it is? It was very difficult for me to make my own experiments in Stellarium. It seemed like it would vary a bit, but not too much.&lt;/p&gt;&#xA;&lt;p&gt;The reason I'm trying to figure this out is both because of general curiosity, and wanting to accurately describe the Sun and Moon in my story. In The Lord of the Rings, Tolkien frequently talks about the movement and look of these objects, which appear to follow the same rules as in our world. It's clear that he had very deep knowledge of how these things appear to move on the sky over the day, and I like such &amp;quot;details&amp;quot; to be accurate.&lt;/p&gt;&#xA;&lt;p&gt;Basically all the animations and illustrations I find of the movement of the Moon and Earth around the Sun are focused on a &amp;quot;space overview&amp;quot; rather than how it looks from Earth.&lt;/p&gt;&#xA;" OwnerUserId="21240" LastActivityDate="2020-10-16T19:36:14.127" Title="Does the Sun and Moon basically appear to &quot;move on the sky&quot; identically regardless of location and date?" Tags="|earth-observation|earth-rotation|sun|moon|earth-moon|" AnswerCount="1" CommentCount="3" ClosedDate="2020-10-18T02:26:07.187" ContentLicense="CC BY-SA 4.0" />
  <row Id="20344" PostTypeId="2" ParentId="20343" CreationDate="2020-10-16T19:36:14.127" Score="1" Body="&lt;p&gt;Like Fred said, this probably belongs on Astronomy SE, but I'll give my best answer anyways.&lt;/p&gt;&#xA;&lt;p&gt;No, the sun and moon do not take the same path each day. The key to understanding this is knowing that the earth is tilted 23.5&lt;span class=&quot;math-container&quot;&gt;$^\circ$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AB4JO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AB4JO.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Let's take an example- the arctic circle. On the summer solstice, the sun doesn't set- It goes around and around (&lt;a href=&quot;https://en.wikipedia.org/wiki/Midnight_sun&quot; rel=&quot;nofollow noreferrer&quot;&gt;called the midnight sun&lt;/a&gt;). In the winter solstice, the sun doesn't rise in the Arctic circle.&lt;/p&gt;&#xA;&lt;p&gt;I think a careful observation of mine might be useful for you. The word Mediterranean means &amp;quot;middle earth.&amp;quot; Tolkien is likely referring to the specific geography- specifically the area around the Mediterranean Sea. In fact, T&lt;a href=&quot;https://en.wikipedia.org/wiki/Middle-earth#Correspondence_with_the_geography_of_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;olkien does state that the Mediterranean is the place he envisioned&lt;/a&gt;, but &lt;a href=&quot;https://en.wikipedia.org/wiki/Middle-earth#Cosmology&quot; rel=&quot;nofollow noreferrer&quot;&gt;he does use a flat earth&lt;/a&gt;, so the cosmology doesn't really match up with reality. This is also another nail in the coffin for flat earthers.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-10-16T19:36:14.127" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20345" PostTypeId="1" CreationDate="2020-10-17T08:40:10.713" Score="1" ViewCount="477" Body="&lt;p&gt;I found rocks looking like this in my backyard but cant get to know what they are or how to find out. Below are pictures&lt;a href=&quot;https://i.stack.imgur.com/dKYvH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dKYvH.jpg&quot; alt=&quot;rock1&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/FdZIH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FdZIH.jpg&quot; alt=&quot;rock 2&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ajJAI.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ajJAI.jpg&quot; alt=&quot;rock 3&quot; /&gt;&lt;/a&gt;&#xA;I don’t know if there’s more info I should mention. If there’s anything please advise&lt;/p&gt;&#xA;" OwnerUserId="21242" LastEditorUserId="21242" LastEditDate="2020-10-17T15:04:34.883" LastActivityDate="2020-10-17T15:04:34.883" Title="What is this red glassy rock" Tags="|geology|rocks|" AnswerCount="1" CommentCount="7" ClosedDate="2020-10-17T16:29:13.187" ContentLicense="CC BY-SA 4.0" />
  <row Id="20346" PostTypeId="2" ParentId="20278" CreationDate="2020-10-17T10:15:34.330" Score="2" Body="&lt;p&gt;Before the transform process of the San Andreas Fault zone we know today, there was indeed a subduction zone event taking place in this same region near now coastal California during the late Jurassic to late Cretaceous periods.&lt;/p&gt;&#xA;&lt;p&gt;Today the city of San Francisco physically represents the aftermath of the ancient clash of mighty tectonic titans as the city and surrounding land and oceanic areas consist of and exists on several terranes and melanges which accreted, or formed, during this time, which make up the assemblage known as the Franciscan Complex. &lt;a href=&quot;https://i.stack.imgur.com/LjMCI.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LjMCI.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;These assemblages are an illustrative historical account of events that formed while the mighty Pacific Plate aggressively rammed its way in an easterly direction toward the equally colossal North American Plate. There was a key player who’s pretty much laid to rest now and that was the ancient tectonic Farallon Plate in this same region off of California before the - modern day, neverending, gorgeous, and ever-dynamic coastline. This ancient plate now rests somewhere underneath Utah or there about, theoretically. Although and obviously not as robust as either plate forcing it into its &lt;em&gt;“Malachi crunch”&lt;/em&gt; (uh oh, now I’m dating my own “&lt;em&gt;...Days&lt;/em&gt;”), it was sizable yet, so while it was forced to dive underneath the North American plate for as much as a mass apparently its size can be, until eventually becoming so plugged up and impeding its displacement from the ongoing movement of the Pacific Plate, forcing it to redirect its great energy force elsewhere. This systematic transition of backed up energy marks the birth of the famous, very active San Andreas transform fault! For more on SAF: &lt;a href=&quot;https://geo.libretexts.org/Bookshelves/Geography_(Physical)/Supplemental_Materials%3A_Physical_Geography_(Lenkeit-Meezan)/08%3A_Shaping_the_Lithosphere/8.03%3A_Orogenesis%2C_Faults_and_Earthquakes&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://geo.libretexts.org/Bookshelves/Geography_(Physical)/Supplemental_Materials%3A_Physical_Geography_(Lenkeit-Meezan)/08%3A_Shaping_the_Lithosphere/8.03%3A_Orogenesis%2C_Faults_and_Earthquakes&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Equally fascinating is that the subduction of the Farallon Plate formed the Sierra Mountain Range orogenesis by way of folding and uplift, while tensional stress of the orogeny stretched things out on both Eastern and Western locations of the Sierra’s and “simultaneously” formed the Great Valley which California’s Central Valley of today was/is vastly part of, as well as the creation of the Great Basin on the far eastern side of the Sierra Nevada Mtn. Range.&lt;/p&gt;&#xA;" OwnerUserId="21243" LastEditorUserId="21243" LastEditDate="2020-10-17T10:23:24.547" LastActivityDate="2020-10-17T10:23:24.547" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20347" PostTypeId="1" CreationDate="2020-10-17T14:39:38.083" Score="3" ViewCount="116" Body="&lt;p&gt;(Please excuse my English)&lt;/p&gt;&#xA;&lt;p&gt;A well known fact about Earth's rotation(around its axis) is that the rotation is slow down due to the tidal friction. And because of it, the length of Day is slowly increasing.&lt;br /&gt;&#xA;Originally, the definition of Second(time) was derived from the day length and Earth's rotation. The original definition of the second was 1 day / 24 / 60 / 60 = 1 day / 86400. However, the modern definition of the second is derived from the atom's oscillation period, for precise time keeping, independent of Earth's rotation, because of irregularity of Earth's rotation. Thus, compared to the original definition, the modern definition of the second has rigidly fixed value.&lt;/p&gt;&#xA;&lt;p&gt;My question is : Someday in future, the length of a day will be longer than 86400 atomic seconds. Then what should future human do?&lt;br /&gt;&#xA;Changing the definition of the second will lead to incredibly complex situations. Also changing the definition of the day will cause tremendous complex situation.&lt;/p&gt;&#xA;" OwnerUserId="20914" LastEditorUserId="20914" LastEditDate="2020-10-18T12:36:40.250" LastActivityDate="2020-10-18T12:36:40.250" Title="Will the definition of the second be changed?" Tags="|time|" AnswerCount="1" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="20348" PostTypeId="2" ParentId="20345" CreationDate="2020-10-17T14:56:12.160" Score="0" Body="&lt;p&gt;See &lt;a href=&quot;https://www.thoughtco.com/red-and-pink-minerals-1440941&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; for some ideas.  You may want to do some testing, at least for Mohs hardness.  But comparing your samples to the typical pictures shown in the referenced site I would guess an alkali feldspar (hardness = 6)  or perhaps rose quartz (hardness =7).  Note the hardnesses, a steel file falls in between at 6.5.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2020-10-17T14:56:12.160" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20350" PostTypeId="1" CreationDate="2020-10-18T00:32:43.870" Score="5" ViewCount="106" Body="&lt;p&gt;I know that, although rare, there are symmetric cold core cyclones (with a few of them even having a shallow cold core). They encompass some occluded extratropical cyclones, some dissipating tropical cyclones in the mid-latitudes, and lots of other groups of cyclones. Some of them can be found at any given time at &lt;a href=&quot;http://moe.met.fsu.edu/cyclonephase/gfs/fcst/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://moe.met.fsu.edu/cyclonephase/gfs/fcst/index.html&lt;/a&gt;. So, I wonder what kind of weather they produce (apart from what can be expected for a low pressure) and how it can be compared to asymmetric cold core cyclones and warm core cyclones, both symmetric and asymmetric.&lt;/p&gt;&#xA;" OwnerUserId="21247" LastEditorDisplayName="user1066" LastEditDate="2020-10-18T13:41:46.143" LastActivityDate="2020-10-18T13:41:46.143" Title="Weather produced by symmetric cold core cyclones" Tags="|meteorology|mesoscale-meteorology|synoptic|cyclone|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20351" PostTypeId="2" ParentId="20347" CreationDate="2020-10-18T02:38:15.840" Score="5" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Someday in future, the length of a day will be longer than 86400 atomic seconds. Then what should future human do?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Having a time standard that works well with the ever improving capabilities of physics and having a time standard that stays in sync with the Earth's rotation are at odds with one another. One solution is to continue to do what we do now.&lt;/p&gt;&#xA;&lt;p&gt;The length of a day is already longer than 86400 atomic seconds. Every once in a while a &lt;a href=&quot;https://en.wikipedia.org/wiki/Leap_second&quot; rel=&quot;nofollow noreferrer&quot;&gt;leap second&lt;/a&gt; is added to keep time as measured by the rotation of the Earth in sync with time as measured by an atomic clock. To date, 37 leap seconds have been added since 1972. This concept will continue to work, at least for the next few to several hundred years. Eventually the Earth's rotation rate will have slowed to such an extent that the leap second trick will no longer work.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Will the definition of the second be changed?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Almost certainly.&lt;/p&gt;&#xA;&lt;p&gt;Scientists will eventually find something that is even better than is the unperturbed ground-state hyperfine transition frequency of the cesium-133 atom as a timekeeping device. That science advances is what science does. It has already been proposed to use pulsars rather than atomic clocks as a more precise timekeeping drive. One thing is certain: The second will not be redefined to be 1/86400 of a day.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2020-10-18T09:20:27.427" LastActivityDate="2020-10-18T09:20:27.427" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20352" PostTypeId="1" AcceptedAnswerId="20354" CreationDate="2020-10-18T05:53:19.867" Score="2" ViewCount="125" Body="&lt;p&gt;Does anybody have any recommendations on books tackling Boundary layer Meteorology? I've seen the book by Roland Stull and Arya, but are there any other more updated ones that are as good as these two?&lt;/p&gt;&#xA;&lt;p&gt;Also, would anyone have a resource for the full solutions to Stull's book for BL Meteorology?&lt;/p&gt;&#xA;&lt;p&gt;Any help would be highly appreciated. Thanks!&lt;/p&gt;&#xA;" OwnerUserId="17926" LastEditorUserId="6298" LastEditDate="2020-10-18T07:18:24.517" LastActivityDate="2020-10-19T04:03:59.167" Title="Recommendations for books on boundary layer Meteorology?" Tags="|meteorology|reference-request|planetary-boundary-layer|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20353" PostTypeId="1" AcceptedAnswerId="20369" CreationDate="2020-10-19T02:17:48.693" Score="3" ViewCount="137" Body="&lt;p&gt;Given the question below, how would the kinematic momentum flux be at the surface layer?&lt;/p&gt;&#xA;&lt;p&gt;For letter a, why would it be that way (positive, negative, or 0)?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gM8Qb.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gM8Qb.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/OvUiP.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OvUiP.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Based on the answer below:&lt;/p&gt;&#xA;&lt;p&gt;I’m not sure if I’ve done it correctly, but this is how I answered it based in your comment below.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;First, I assumed that &lt;span class=&quot;math-container&quot;&gt;$\overline{u’w’}$&lt;/span&gt; = &lt;span class=&quot;math-container&quot;&gt;$\overline{w’u’}$&lt;/span&gt;. So is this something like the mixing of horizontal momentum into areas of lower wind speed (as is the case in the surface layer)?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/612z0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/612z0.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17926" LastEditorUserId="17926" LastEditDate="2020-10-26T01:14:00.653" LastActivityDate="2020-10-26T01:14:00.653" Title="Horizontal momentum flux in the surface layer" Tags="|meteorology|planetary-boundary-layer|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20354" PostTypeId="2" ParentId="20352" CreationDate="2020-10-19T04:03:59.167" Score="2" Body="&lt;p&gt;Is there any particular aspect of boundary layer meteorology? Or just something general?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;NOTE&lt;/strong&gt;: I have &lt;strong&gt;not&lt;/strong&gt; read all of these nor do I know anyone who has read these, but judging by the year published or level of detail, these may serve whatever purpose you want. I found these mostly by Googling. I recommend looking at the preview offered in each website.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/B01DM26POW&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Turbulence by John Wyngaard- published in 2010&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.google.com/books/edition/Fundamentals_of_Boundary_Layer_Meteorolo/u9IxDwAAQBAJ?hl=en&amp;amp;gbpv=0&amp;amp;kptab=overview&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fundamentals of Boundary-Layer Meteorology&lt;/a&gt; by Xuhui Lee was published in 2017, but from the brief look inside, I don't see a large difference from Stull or Arya.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.google.com/books/edition/Atmospheric_Boundary_Layer/QKVwCQAAQBAJ?hl=en&amp;amp;gbpv=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atmospheric Boundary Layer Integrating Air Chemistry and Land Interactions (2015)&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.google.com/books/edition/Turbulence_and_Dispersion_in_the_Planeta/_pUoDQAAQBAJ?hl=en&amp;amp;gbpv=0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Turbulence and Dispersion in the Planetary Boundary Layer By Francesco Tampieri · 2016&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-10-19T04:03:59.167" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20358" PostTypeId="2" ParentId="15754" CreationDate="2020-10-19T23:44:01.920" Score="1" Body="&lt;p&gt;Agricultural water is largely &lt;a href=&quot;https://en.wikipedia.org/wiki/Fossil_water&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fossil Water&lt;/a&gt;, which took tens of thousands of years to accumulate and industrial activities have used it in a century.&lt;br /&gt;&#xA;Saudi Arabia is &lt;a href=&quot;https://www.world-grain.com/articles/6275-saudi-arabia-ends-domestic-wheat-production-program&quot; rel=&quot;nofollow noreferrer&quot;&gt;abandoning programs to grow wheat&lt;/a&gt; that achieved self-sufficiency but depleted the desert kingdom's scarce water supplies. Going from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Agriculture_in_Saudi_Arabia&quot; rel=&quot;nofollow noreferrer&quot;&gt;6th largest exporter&lt;/a&gt; to NO more. Humanity derives water sources from mountain runoff, aquifers or lakes/rivers/ponds.........It must come from sources with much more rapid rain regeneration to be useful.&#xA;Water has to Percolate into the ground. That takes months or years and the aquifers in question........they've had 10,000 years of water accumulation. Artificial rainfall regeneration, water can be diverted after a storm to be partially filtered and allowed to flow thru gutters, culverts, trenches, etc and flow into retention basins where it'll percolate into dug wells.&#xA;The venetians used this technique as the city of Venice had no reliable water table to draw from. The water would fall thru dense layers of sand and come thru a cistern. And that was the pinnacle of water catchment technology for a millennia.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/hKNt4.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hKNt4.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;Another is the recharge pit used to regenerate abandoned wells that have been drained by prolonged use. The well's main pipe is dug 10 feet down and several feet out, then the bottom foot of the pipe is drilled to permit water to flow into it. Wrapped in a mesh/protective layer so water can flow but debris and particles cannot. Then the first 3 feet are lined with large rocks/boulders then the next 3 feet lined with smaller rocks and cobble. This is to press against the pit to keep it's inner wall from collapsing in on itself. often the next layer is a permeable filter fabric filled with activated charcoal then lined with course sand and regular fine compacted sand. Redirected rainwater entering the pit will slowly filter into the layers then fill the well. This discharge allows water wells long abandoned to be refilled using the rainy monsoon seasons water to sustain agricultural activity in the hotter dry season.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ivc87.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ivc87.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastEditorUserId="21028" LastEditDate="2020-11-06T03:38:56.353" LastActivityDate="2020-11-06T03:38:56.353" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20359" PostTypeId="2" ParentId="14346" CreationDate="2020-10-20T00:10:45.020" Score="0" Body="&lt;p&gt;Every thing in Yellow is the &amp;quot;Subtropical&amp;quot; zone. Mountains augment climate in many ways, one is the rainshadow effect when warm moist air rises it interacts and accumulates on the mountains. Ice/snow if the mountain is particiularly tall, at the lower altitudes rain is frequent. Vegetation often very adapted to bizarre temperature swings. Producing very exotic plant species.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/QOnrg.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QOnrg.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-10-20T00:10:45.020" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20361" PostTypeId="2" ParentId="17530" CreationDate="2020-10-20T00:14:07.370" Score="-1" Body="&lt;p&gt;Actually it does. But the thermo-haline cycle of cold water and upwelling mixes that water around. In stagnant stand, the salt will accumulate on the bottom. But ocean currents and the rise and fall of varying temperature water flushes that salt and moves it around.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-10-20T00:14:07.370" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20362" PostTypeId="1" CreationDate="2020-10-20T12:37:51.507" Score="1" ViewCount="158" Body="&lt;p&gt;Multiple websites state that the mountain, which is in Colorado, was formed by an intrusion of magma about 1.4 billion years ago, forming a batholith.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, the rocky mountains are said to have been formed only recently, perhaps 80 to 50 million years ago.&lt;/p&gt;&#xA;&lt;p&gt;What then were the major forces that shaped the mountain? Did the batholith 1.4 billion years ago start thrusting the ground upward like a dome mountain, or did it remain flush underground until tectonic plate movement formed all of the rocky mountains?&lt;/p&gt;&#xA;" OwnerUserId="21257" LastActivityDate="2020-10-27T04:53:22.170" Title="How did Mount Evans become a mountain?" Tags="|geology|mountains|mountain-building|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20363" PostTypeId="1" CreationDate="2020-10-20T13:45:53.747" Score="1" ViewCount="48" Body="&lt;p&gt;Assume that we're talking about a terraformed Venus with an Earth-like atmosphere so no risk of the water simply boiling away before being allowed to permeate the lithosphere.  Does this meet the sufficient criteria for plate tectonics, and would there be any factors may prevent it?&lt;/p&gt;&#xA;" OwnerUserId="21258" LastEditorUserId="6298" LastEditDate="2020-11-01T03:37:17.830" LastActivityDate="2020-11-01T03:37:17.830" Title="Does science suggest Venus would resume plate tectonics if surface water were somehow reintroduced and rotation sped up?" Tags="|geology|water|" AnswerCount="0" CommentCount="3" ClosedDate="2020-10-21T14:43:06.623" ContentLicense="CC BY-SA 4.0" />
  <row Id="20364" PostTypeId="1" CreationDate="2020-10-20T20:29:14.663" Score="2" ViewCount="374" Body="&lt;p&gt;By Hydrostatical Law, &lt;span class=&quot;math-container&quot;&gt;$p_a = \rho gh$&lt;/span&gt;, at a given &lt;span class=&quot;math-container&quot;&gt;$h$&lt;/span&gt;. However density varies with altitude and with temperature. Temperature varies by altitude. &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; constant varies with altitude.&lt;/p&gt;&#xA;&lt;p&gt;How to express the law of atmospheric pressure?&lt;/p&gt;&#xA;" OwnerUserId="21260" LastActivityDate="2020-10-21T13:19:14.463" Title="Variation of the atmospheric pressure" Tags="|atmosphere|geophysics|temperature|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20367" PostTypeId="2" ParentId="20364" CreationDate="2020-10-21T13:19:14.463" Score="3" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;By Hydrostatical Law, &lt;span class=&quot;math-container&quot;&gt;$p_a = \rho gh$&lt;/span&gt;, at a given &lt;span class=&quot;math-container&quot;&gt;$h$&lt;/span&gt;. However density varies with altitude and with temperature. Temperature varies by altitude. &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; constant varies with altitude.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;That expression is for water, which has more or less constant density, and it is for depth rather than height.&lt;/p&gt;&#xA;&lt;p&gt;Ynou need to change this to a differential equation. This is fairly easy: &lt;span class=&quot;math-container&quot;&gt;$$\frac{dP(h)}{dh} = -\rho g\tag{1}$$&lt;/span&gt;&#xA;This assumes the atmosphere is in hydrostatic equilibrium: Every layer of the atmosphere bears the weight of all of the mass above the layer.&lt;/p&gt;&#xA;&lt;p&gt;Another key equation is the ideal gas law, &lt;span class=&quot;math-container&quot;&gt;$PV=nRT$&lt;/span&gt;. This can be rewritten in terms of local density as &lt;span class=&quot;math-container&quot;&gt;$$P = \rho R_s T\tag{2}$$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$R_s$&lt;/span&gt; is the specific gas constant, the ideal gas constant divided by the mean molecular mass of the gas. Combining equations (1) and (2) yields &lt;span class=&quot;math-container&quot;&gt;$$\frac{dP}{dh} = -\frac{g}{R_s T} P\tag{3}$$&lt;/span&gt;&#xA;Assuming that all of the factors &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$R_s$&lt;/span&gt;, and &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; are constant results in an exponential: &lt;span class=&quot;math-container&quot;&gt;$$P(h) = P_0 \exp\left(-\frac{g}{R_s T}h\right) = P_0 \exp\left(-\frac{h}{H}\right)\tag{4}$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$P_0$&lt;/span&gt; is the pressure at the surface and &lt;span class=&quot;math-container&quot;&gt;$H$&lt;/span&gt; is the scale factor height, &lt;span class=&quot;math-container&quot;&gt;$H=R_s T / g$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The exponential atmosphere model assumes constant temperature. This is not a valid assumption. Temperature drops with increasing altitude in the troposphere, rises with increasing altitude in the stratosphere, and drops again with increasing altitude in the mesosphere. Above the mesosphere, the assumptions of a specific gas constant and constant gravitational acceleration also fail.&lt;/p&gt;&#xA;&lt;p&gt;The assumptions of a specific gas constant and constant gravitational acceleration are approximately valid in the troposphere. An approximate model for temperature in the troposphere is to assume a constant lapse rate &lt;span class=&quot;math-container&quot;&gt;$L$&lt;/span&gt;: &lt;span class=&quot;math-container&quot;&gt;$$T(h) = T_0 - L h\tag{5}$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$T_0$&lt;/span&gt; is the temperature at the surface and &lt;span class=&quot;math-container&quot;&gt;$L$&lt;/span&gt; is the lapse rate, the rate at which temperature decreases with altitude. Combining equations (3) and (5) results in a solvable first order differential equation, with solution &lt;span class=&quot;math-container&quot;&gt;$$P = P_0 \left(1-\frac{L}{T_0}h\right)^{\frac{g}{R_s L}}\tag{6}$$&lt;/span&gt;&#xA;This still assumes constant gravity and and constant atmospheric composition, and it assumes hydrostatic equilibrium (equation 1) and an ideal gas (equation 2). None of these are even approximately true above the mesosphere.&lt;/p&gt;&#xA;&lt;p&gt;Increasing accuracy means that atmosphere models become ever more empirical. The models are still tied to physics, but they are also tied to observations. Lower atmosphere weather models have to eliminate the assumptions that pressure, temperature, and atmospheric makeup are functions of elevation only. Upper atmosphere models have to account for variations in solar radiation. One solar flare can make the upper atmosphere expand by over an order of magnitude.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-10-21T13:19:14.463" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20368" PostTypeId="2" ParentId="14492" CreationDate="2020-10-21T15:11:03.590" Score="2" Body="&lt;p&gt;@Muze “What would the color be if all of the dirt on Earth was added equally to a palette?” The average color of dirt is Pantone Warm Grey #11C.&lt;img src=&quot;https://i.stack.imgur.com/oNeox.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;" OwnerUserId="21262" LastEditorUserId="21262" LastEditDate="2020-10-21T15:29:09.363" LastActivityDate="2020-10-21T15:29:09.363" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20369" PostTypeId="2" ParentId="20353" CreationDate="2020-10-21T17:47:05.853" Score="3" Body="&lt;p&gt;Instead of just giving you the answer to a textbook problem (which would make SE a version of Chegg that future students would use to cheat on homework), I'll guide you in getting an answer.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Which variable does &lt;span class=&quot;math-container&quot;&gt;$\overline{u'w'}$&lt;/span&gt; affect most?&lt;/li&gt;&#xA;&lt;li&gt;For that variable, identify the surface layer.&lt;/li&gt;&#xA;&lt;li&gt;Imagine that you are on the line. If you go straight up (that is, &lt;span class=&quot;math-container&quot;&gt;$w'&amp;gt;0$&lt;/span&gt;) what would the difference be between the &lt;span class=&quot;math-container&quot;&gt;$M$&lt;/span&gt; traced out and the graphed &lt;span class=&quot;math-container&quot;&gt;$M$&lt;/span&gt;? What is the sign of &lt;span class=&quot;math-container&quot;&gt;$w' \times u'$&lt;/span&gt;?&lt;/li&gt;&#xA;&lt;li&gt;Do the same as number 3, except start at the top and go down (&lt;span class=&quot;math-container&quot;&gt;$w'&amp;lt;0$&lt;/span&gt;).&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-10-21T17:47:05.853" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20370" PostTypeId="1" CreationDate="2020-10-21T21:51:21.680" Score="1" ViewCount="129" Body="&lt;p&gt;CO2 is heavier than air (1.51 while oxygen is 1.1 and nitrogen is 0.97), however when combusted, it will initially rise until it's temperature gets closer to that of air (about 1000 feet), then it will tend to fall. CO2 is a reluctant defusser and mixer, so how does it get from 1000 to 10,000 feet - what lifts CO2 up?&lt;/p&gt;&#xA;" OwnerUserId="21263" LastActivityDate="2020-11-21T01:35:20.483" Title="CO2's rise up into the atmosphere" Tags="|atmosphere|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20371" PostTypeId="1" AcceptedAnswerId="20389" CreationDate="2020-10-22T07:47:54.473" Score="6" ViewCount="234" Body="&lt;p&gt;Let's say at some point in the future we have an abundance of fresh water (for example because we have enough energy to power many desalination plants) and we can turn the Sahara into green land by supplying it with a lot of watter and nutrients&lt;/p&gt;&#xA;&lt;p&gt;What would happen once we stop the water supply? Could the green Sahara sustain itself?&lt;/p&gt;&#xA;" OwnerUserId="21268" LastEditorUserId="21268" LastEditDate="2020-10-26T07:38:22.640" LastActivityDate="2020-12-04T09:42:09.870" Title="If we could green the Sahara, would it be able to sustain itself?" Tags="|climate|desert|rain|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20372" PostTypeId="1" CreationDate="2020-10-22T12:50:30.983" Score="1" ViewCount="140" Body="&lt;p&gt;&lt;strong&gt;To save the Earth, the surface of the Earth has been covered by silver foil. The foil has a albedo of 0.9. What is the flux density emitted from the surface of the Earth (assume temperature of 50 deg C)?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;So I thought I could use Stefan Boltzmann law and just plugg in my values and got 569, but this is not correct. What I'm I missing?&lt;/p&gt;&#xA;" OwnerUserId="21126" LastActivityDate="2020-10-22T15:05:33.537" Title="Flux density and albedo" Tags="|atmospheric-radiation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20373" PostTypeId="2" ParentId="20372" CreationDate="2020-10-22T15:05:33.537" Score="2" Body="&lt;p&gt;In your calculation, did you use albedo correctly? Remember, &lt;a href=&quot;https://glossary.ametsoc.org/wiki/Albedo&quot; rel=&quot;nofollow noreferrer&quot;&gt;albedo is the ratio of reflected radiation to total radiation&lt;/a&gt;, and 1-albedo is the ratio of absorbed radiation to total radiation.&lt;/p&gt;&#xA;&lt;p&gt;Edit: Make sure you are plugging the numbers in correctly too.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-10-22T15:05:33.537" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20374" PostTypeId="1" CreationDate="2020-10-22T19:09:45.017" Score="1" ViewCount="15" Body="&lt;p&gt;I am looking for the full names of the lithology classifications SC7 and SC10. According to the &lt;a href=&quot;http://www.fao.org/3/a-a0541e.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;FAO's guidelines for soil description&lt;/a&gt; SC3 e.g. refers to &lt;em&gt;silt-, mud-, claystone&lt;/em&gt;. What do SC7 and SC10 refer to?&lt;/p&gt;&#xA;" OwnerUserId="21272" LastActivityDate="2020-10-22T19:09:45.017" Title="SC7 and SC10 Lithology Classifications" Tags="|geology|geography|sedimentology|soil|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20377" PostTypeId="1" CreationDate="2020-10-24T01:07:15.677" Score="1" ViewCount="71" Body="&lt;p&gt;Assuming that the divergence varies linearly with the pressure between the surface&#xA;(1000 hPa) and the tropopause (200 hPa). Can someone tell me how do we calculate the vertical speed on the pressure surface of 700 hPa if the maximum vertical speed in this column of air is 1 Pa/s?&lt;/p&gt;&#xA;" OwnerUserId="11400" LastActivityDate="2020-10-27T21:09:27.500" Title="Vertical air speed" Tags="|meteorology|atmospheric-circulation|fluid-dynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20378" PostTypeId="1" AcceptedAnswerId="20379" CreationDate="2020-10-24T06:11:52.280" Score="5" ViewCount="3258" Body="&lt;p&gt;The Kola drill went 'only' a third the way to the mantle, so its deepest point was still closer to the surface than to the mantle. Why did the drillers experience 180 °C when so deep, where did that heat come from? Logically I'd expect it would get colder the deeper you went into the crust (until about halfway to the mantle I guess where temperature started rising again), not hotter.&lt;/p&gt;&#xA;" OwnerUserId="21276" LastEditorUserId="725" LastEditDate="2021-09-23T01:25:34.857" LastActivityDate="2021-09-23T01:25:34.857" Title="What's the official reason why it became so hot in the Kola borehole?" Tags="|crust|mantle|drilling|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20379" PostTypeId="2" ParentId="20378" CreationDate="2020-10-24T09:11:36.380" Score="11" Body="&lt;p&gt;Unfortunately, you intuition about subterranean ground temperatures is incorrect.&lt;/p&gt;&#xA;&lt;p&gt;Basements and cellars do provide cooler conditions to store perishable items because the near surface rock insulates against surface heat.&lt;/p&gt;&#xA;&lt;p&gt;Go deeper however and temperature increases. Near the Earth's surface, within the crust, and away from tectonic boundaries, the rate of temperature increase, due to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Geothermal_gradient&quot; rel=&quot;noreferrer&quot;&gt;geothermal gradient&lt;/a&gt; is  25–30 °C/km. The geothermal gradient increases with depth.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EXH1X.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EXH1X.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Most of the heat is due to the decay of naturally radioactive elements,mostly within the mantle.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Heat flows constantly from its sources within Earth to the surface. Total heat loss from Earth is estimated at 44.2 TW.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-10-24T09:11:36.380" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="20380" PostTypeId="1" AcceptedAnswerId="20381" CreationDate="2020-10-24T18:14:43.203" Score="5" ViewCount="408" Body="&lt;p&gt;&lt;a href=&quot;https://www.grc.nasa.gov/WWW/K-12/airplane/atmosmet.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA's page about Earth atmosphere models&lt;/a&gt; gives a weird equation about temperature change in different atmospheric layers. One of the formulas looks like this:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/71Ioj.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/71Ioj.png&quot; alt=&quot;&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Can someone explain to me what this means?&lt;/p&gt;&#xA;" OwnerUserId="21280" LastEditorUserId="111" LastEditDate="2020-10-25T01:58:03.333" LastActivityDate="2020-10-25T18:00:36.100" Title="Temperature change in Earth atmosphere models?" Tags="|atmosphere|atmosphere-modelling|barometric-pressure|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20381" PostTypeId="2" ParentId="20380" CreationDate="2020-10-24T18:20:52.853" Score="11" Body="&lt;p&gt;There's some kind of explanation about the units under the picture. The formula is based off the &lt;a href=&quot;https://energyeducation.ca/encyclopedia/Temperature_of_the_Earth#cite_note-RE1-3&quot; rel=&quot;noreferrer&quot;&gt;average temperature in degrees Celsius (measured over the entire year, and the entire Earth)&lt;/a&gt;, which is 15.04 at sea level, and the temperature decreases by 0.00649 degrees every meter above sea level (the average &lt;a href=&quot;https://www.britannica.com/science/normal-lapse-rate&quot; rel=&quot;noreferrer&quot;&gt;lapse rate&lt;/a&gt;). The formula is 'valid' until 11 kilometers, where the troposphere ends.&lt;/p&gt;&#xA;&lt;p&gt;It's just a model of the average temperature; of course, at the poles it will be colder and at the equator it will be warmer. The lapse rate also varies, while the average of 6.5 °C per kilometer is quite well-known, it can vary between 9.8 °C when it's dry and about 5 °C when it's moist; see &lt;a href=&quot;https://en.wikipedia.org/wiki/Lapse_rate#Mathematics_of_the_adiabatic_lapse_rate&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt; for the derivation of these rates.&lt;/p&gt;&#xA;" OwnerUserId="2958" LastEditorUserId="2958" LastEditDate="2020-10-25T10:47:55.970" LastActivityDate="2020-10-25T10:47:55.970" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="20384" PostTypeId="1" CreationDate="2020-10-25T19:59:11.180" Score="2" ViewCount="159" Body="&lt;p&gt;how can I regrid my NetCDF file into another NetCDF file resolution?&#xA;change the file number 1 or 2 or 3 (file1.nc,file2.nc,file3.nc ) into resolution template file (wrfinput_d01.nc) . I have attached my files(number1,2,3 and template file)&#xA;wrfinput file:&#xA;&lt;a href=&quot;https://drive.google.com/file/d/1j6SrSOpbrkWXDl2_WK-MGwcm0zKOXV_x/view?usp=sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://drive.google.com/file/d/1j6SrSOpbrkWXDl2_WK-MGwcm0zKOXV_x/view?usp=sharing&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;my files 1,2:&#xA;&lt;a href=&quot;https://drive.google.com/file/d/1-o7TUcPmzsuOYhpry92ROHQuLA1Z5N-x/view?usp=sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://drive.google.com/file/d/1-o7TUcPmzsuOYhpry92ROHQuLA1Z5N-x/view?usp=sharing&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;cdo griddes wrfinput_d01.nc &amp;gt; NEW_GRID_DEF&#xA;cdo remapbil,NEW_GRID_DEF file1.nc output.nc&lt;/p&gt;&#xA;&lt;p&gt;I've done it by cdo, but it shows error&#xA;Error (cdfGetSliceSlapDescription): Internal error, variable evi has an unsupported array structure!&#xA;What shall I do to solvr this problem?&#xA;thank you!&lt;/p&gt;&#xA;" OwnerUserId="18881" LastActivityDate="2020-10-25T22:37:54.753" Title="regeride netcdf file to template netcdf file resoulution" Tags="|wrf|wrf-chem|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20385" PostTypeId="2" ParentId="20384" CreationDate="2020-10-25T22:37:54.753" Score="6" Body="&lt;p&gt;&lt;strong&gt;Disclaimer&lt;/strong&gt;: I have not looked at your particular files.&lt;/p&gt;&#xA;&lt;p&gt;You can regrid the data in Python using the &lt;a href=&quot;https://unidata.github.io/netcdf4-python/netCDF4/index.html&quot; rel=&quot;noreferrer&quot;&gt;NetCDF-4 module&lt;/a&gt;. If you want to interpolate vertically, you can use the &lt;a href=&quot;https://wrf-python.readthedocs.io/en/latest/user_api/index.html#interpolation-routines&quot; rel=&quot;noreferrer&quot;&gt;WRF&lt;/a&gt; module. And for horizontal interpolation, you can use the &lt;a href=&quot;https://docs.scipy.org/doc/scipy/reference/interpolate.html&quot; rel=&quot;noreferrer&quot;&gt;Scipy Interpolation&lt;/a&gt; module.&lt;/p&gt;&#xA;&lt;p&gt;Here is how you would go about this regridding.&lt;/p&gt;&#xA;&lt;p&gt;Let &lt;span class=&quot;math-container&quot;&gt;$(\psi_1,\phi_1)$&lt;/span&gt; be the  latitude and longitude of the original data and &lt;span class=&quot;math-container&quot;&gt;$(\psi_2,\phi_2)$&lt;/span&gt; of the regridded data. Let &lt;span class=&quot;math-container&quot;&gt;$y_1$&lt;/span&gt; be your original data, and &lt;span class=&quot;math-container&quot;&gt;$y_2$&lt;/span&gt; be the regridded data.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Open the original dataset.&lt;/li&gt;&#xA;&lt;li&gt;Create an interpolation function trained on your original data &lt;span class=&quot;math-container&quot;&gt;$f(\psi_1,\phi_1)$&lt;/span&gt; for the data you will regrid.&lt;/li&gt;&#xA;&lt;li&gt;Using the NetCDF module, declare the dimensions, variables, and necessary metadata for your regridded dataset.&lt;/li&gt;&#xA;&lt;li&gt;Use your interpolation function, so you get &lt;span class=&quot;math-container&quot;&gt;$y_2=f(\psi_2,\phi_2)$&lt;/span&gt;.&lt;/li&gt;&#xA;&lt;li&gt;If necessary, interpolate to your required vertical level.&lt;/li&gt;&#xA;&lt;li&gt;Repeat starting on step 2 for every time for every variable that you want, at every vertical level (if required).&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-10-25T22:37:54.753" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20386" PostTypeId="1" CreationDate="2020-10-26T03:17:10.727" Score="3" ViewCount="151" Body="&lt;p&gt;In deriving the prognostic equation for the mean quantity of pollutant C, as shown in my solution below:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Am I right in that I do not need to separate T (temperature) into its mean and turbulent parts (like &lt;span class=&quot;math-container&quot;&gt;$T = \overline{T}$&lt;/span&gt; + t’)? If I am right, is it because T does not depend on anything in this equation?&lt;/li&gt;&#xA;&lt;li&gt;When assuming horizontal homogeneity in the x-direction, this means that the change in c with respect to x (dc/dx = 0) is zero. So does that leave the final prognostic equation with no advective terms since I aligned U to be in X also?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iyr9w.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iyr9w.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Thanks for any help!&lt;/p&gt;&#xA;" OwnerUserId="17926" LastEditorUserId="17926" LastEditDate="2020-10-27T01:48:57.900" LastActivityDate="2022-03-21T05:06:25.610" Title="Question on the derivation of a prognostic equation for the mean concentration (Assume horizontal homogeneity in X)" Tags="|meteorology|planetary-boundary-layer|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20387" PostTypeId="1" CreationDate="2020-10-27T00:50:41.837" Score="3" ViewCount="117" Body="&lt;p&gt;Atmospheric potential gradient changes during the day, as different areas of lightning activity come under Sun.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/m1HcL.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/m1HcL.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This illustration from &amp;quot;The Carnegie Curve&amp;quot; by R. Giles Harrison shows contribution of different regions.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5BCnG.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5BCnG.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Why region curves are so narrow and high - about 6 hours wide if lightning storms go day and night? As I understand most of cloud energy is stored in latent steam heat, so why sunlight makes such big contribution?&lt;/p&gt;&#xA;" OwnerUserId="21286" LastActivityDate="2020-11-20T22:10:19.507" Title="Lightning activity day curve - why it has high and narrow peak?" Tags="|meteorology|lightning|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20388" PostTypeId="2" ParentId="20386" CreationDate="2020-10-27T01:56:11.050" Score="1" Body="&lt;p&gt;In the question, T was not specifically mentioned to be a constant. So by also expanding &lt;span class=&quot;math-container&quot;&gt;$T = \overline{T} + t’$&lt;/span&gt;, we end up with the following answer. Where, the covariance term containing &lt;span class=&quot;math-container&quot;&gt;$\overline{c’t’}$&lt;/span&gt; reflects that turbulence still plays a role in determining the mean quantity of C.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YZZAb.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YZZAb.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17926" LastEditorUserId="17926" LastEditDate="2020-10-27T02:03:12.147" LastActivityDate="2020-10-27T02:03:12.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20389" PostTypeId="2" ParentId="20371" CreationDate="2020-10-27T03:30:01.807" Score="5" Body="&lt;p&gt;The biggest detriment to keeping deserts green is of course water. With rainfall in the desert limited, afforestation is a tricky and potentially dangerous thing to do. &lt;a href=&quot;https://en.wikipedia.org/wiki/Afforestation#China&quot; rel=&quot;nofollow noreferrer&quot;&gt;China tried this for decades with afforestation efforts&lt;/a&gt;, planting billions of trees in steppe regions of China and Mongolia, only to later worsen because the trees consumed too much ground water and lowered the water table.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/StfnR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/StfnR.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, trees behave like humidifiers, the little moisture that accumulates at night may collect on the trees and fall as dew, replenishing some soil moisture. Reforestation campaigns in deserts are questionable efforts, without artificial watering or human maintenance they usually die. However active afforestation campaigns in semi-deserts bear some merit. However, there's no evidence of artificially planted forest sustaining itself in such an arid environment without human intervention.&lt;/p&gt;&#xA;&lt;p&gt;Another example are drought tolerant trees, like acacias, planted in the Sahara. These may very well sustain themselves with their ability to settle and accumulate more water.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/E3NLC.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/E3NLC.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;They provide shade and so prevent the surface soil from overheating, which has several benefits&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;With cooler soil, the little soil moisture that falls here can percolate into the ground without evaporating&lt;/li&gt;&#xA;&lt;li&gt;It shades wildlife from extreme heat (who in turn produce fertilzer i.e. manure/urine)&lt;/li&gt;&#xA;&lt;li&gt;The areas under trees become attractive nesting sites for birds who nest in winter&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;For more examples of greened ecosystems, there's the Hawaiian island of &lt;a href=&quot;https://en.wikipedia.org/wiki/Ni%CA%BBihau&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ni'ihau&lt;/a&gt;. This is privately owned and very arid because of the rainshadow effect. The owners planted tens of thousands of trees a year for decades. As a result, the trees act as a humidifier to collect what little atmospheric moisture accumulates at night when it's cooler.&lt;/p&gt;&#xA;&lt;p&gt;Another example is &lt;a href=&quot;https://en.wikipedia.org/wiki/Ascension_Island&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ascension Island&lt;/a&gt;. In the 1850s, botanists (under encouragement by Charles Darwin) started shipping trees to the island. In mere decades, the peak of the island became a cloud forest.&lt;a href=&quot;https://i.stack.imgur.com/cZ0me.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cZ0me.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;I don't know if such examples are self sustaining. I can only say it's &amp;quot;Plausible&amp;quot;. Ascension Island is not well developed, therefore little maintenance is done on the forest above, and it's a national park.&#xA;In more arid regions, it's possible but don't expect a full blown forest. You might see a semi-arid scrub forest.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/8cI1N.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8cI1N.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastEditorUserId="21448" LastEditDate="2020-12-04T09:42:09.870" LastActivityDate="2020-12-04T09:42:09.870" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20391" PostTypeId="2" ParentId="20362" CreationDate="2020-10-27T04:53:22.170" Score="1" Body="&lt;p&gt;Just to elaborate on David Hammen's correct comment:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The granite is old. The mountain is fairly young. There is no&#xA;contradiction&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Mountain belts like the Rockies are built by tectonic forces. Two plate collide, and mountains rise in between. The material that makes up the mountain does not have to form during the collision (although it sometime does).&lt;/p&gt;&#xA;&lt;p&gt;A &amp;quot;batholith&amp;quot; is just a collection of many granite intrusions, which are mostly underground. They do not have to be mountainous. In most cases they are covered by sedimentary rocks and you don't even know they're there. They only become mountains when you &amp;quot;fold&amp;quot; them. When you fold a piece of paper and it wrinkles, you have to separate the formation of the wrinkles (which happened now) from the manufacturing of the paper (which was in a paper factory, in the past).&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-10-27T04:53:22.170" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20392" PostTypeId="2" ParentId="2176" CreationDate="2020-10-27T07:06:54.853" Score="0" Body="&lt;p&gt;Land use patterns affect desertification in the short run. However increase in temperature along with more Carbon dioxide will Green the desert with more applicable vegetation. Right before the 8.2 kiloyear event the Sahara wasn't a desert but a grassland and tree dominant area, much like the savanna. Some simulations of global warming and increased carbon dioxide concentrations have shown a substantial increase in precipitation in the Sahel/Sahara. Because atmospheric humidity from the Atlantic and Mediterranean Sea and Indian oceans will provide More humidity. Using NOAA AVHRR NDVI-data from 1982 to 1999 the Sahel region below the desert has been greening.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/gaU01.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gaU01.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-10-27T07:06:54.853" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20393" PostTypeId="2" ParentId="20377" CreationDate="2020-10-27T21:09:27.500" Score="1" Body="&lt;p&gt;That's... a pretty specific question.&lt;/p&gt;&#xA;&lt;p&gt;Well, we start with making assumptions. Let's write the continuity equation with the Boussinesq approximation: &lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial \omega}{\partial P}=-\frac{\partial u}{\partial x}-\frac{\partial v}{\partial y}=D\tag{1}$$&lt;/span&gt;. If we assume a priori that the divergence varies linearly with pressure, then we can write divergence in point-slope form: &lt;span class=&quot;math-container&quot;&gt;$$D(P)=\frac{D(1000 \text{ hPa})-D(200 \text{ hPa})}{1000 \text{ hPa}-200 \text{ hPa}}\left(P-200 \text{ hPa}\right)+D(200\text{ hPa})=mP+b \tag{2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Let's combine (1) and (2): &lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial \omega}{\partial P}=mP+b$$&lt;/span&gt;. Integrating over P yields &lt;span class=&quot;math-container&quot;&gt;$$\omega(P)=\frac{1}{2}mP^2+bP+P_0+\omega(P_0)$$&lt;/span&gt;. I'll let you plug in your numbers.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-10-27T21:09:27.500" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20394" PostTypeId="2" ParentId="20387" CreationDate="2020-10-28T12:30:24.603" Score="3" Body="&lt;p&gt;I think the simple answer to your question is that sunlight widens the potential area for storms by producing a better convective environment, whereas nocturnal storms are highly localized based on climatological factors.&lt;/p&gt;&#xA;&lt;p&gt;While a minority of storms do occur overnight due to local mesoscale features such as nocturnal low-level jets, the majority of storms will occur because of convective forcing. To have a convective environment, you have to have a parcel of air that is warmer than that of the environment it is traveling through, and that is what gives you lift. The easiest way for that to happen is to have parcels rise up from the ground at the peak heating of the day while the ground is much warmer than the air above it.&lt;/p&gt;&#xA;&lt;p&gt;In an older (and still infinitely useful) thought process of meteorology, there is a temperature known as the &amp;quot;convective temperature&amp;quot; that can be gotten from a Skew-T diagram. It takes into account the dewpoint and vertical temperature profile of the atmosphere and produces a temperature at which the surface level has to get to in order to set off thunderstorms. The best way to get to and beyond that temperature is through the heating of the sun. Additionally, when the air is warmed through heating from the sun it makes the environment ripe for convective initiation through triggers such as fronts.&lt;/p&gt;&#xA;" OwnerUserId="13660" LastActivityDate="2020-10-28T12:30:24.603" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20395" PostTypeId="1" CreationDate="2020-10-28T14:37:18.267" Score="4" ViewCount="53" Body="&lt;p&gt;Zeke Hausfather &lt;a href=&quot;https://twitter.com/hausfath/status/1321154927440195584&quot; rel=&quot;nofollow noreferrer&quot;&gt;tweets&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Just six years ago many in the scientific community were obsessing&#xA;over the apparent &amp;quot;pause&amp;quot; or &amp;quot;hiatus&amp;quot; in surface temperatures. It&#xA;famously made it into the 2013 IPCC report in Box 9.2, which featured&#xA;this 15-yr comparison with climate models.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xjUEL.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xjUEL.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Clearly a lot of research was performed on the subject of the pause/hiatus (as demonstrated by it featuring in the IPCC report), but my question is what were the significant changes to our understanding of the &lt;em&gt;apparent&lt;/em&gt; (1) pause/hiatus adding/overturning the explanation given by &lt;a href=&quot;https://iopscience.iop.org/article/10.1088/1748-9326/6/4/044022/meta&quot; rel=&quot;nofollow noreferrer&quot;&gt;Foster and Rahmstorf&lt;/a&gt; in 2011 (largely ENSO, volcanic forcing and solar variation).&lt;/p&gt;&#xA;&lt;p&gt;Obviously some of the research was on like-for-like comparison of models and observations and biases in the observations, but I am more interested in our understanding of internal climate variability.&lt;/p&gt;&#xA;&lt;p&gt;(1) &amp;quot;Apparent&amp;quot; as there was no statistically significant evidence for the existence of a change in the underlying rate of warming, and as Hausfather &lt;a href=&quot;https://twitter.com/hausfath/status/1321154930640519168&quot; rel=&quot;nofollow noreferrer&quot;&gt;points out&lt;/a&gt;, a careful analysis of the last fifteen years worth of data tells the opposite story.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Wgn5x.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Wgn5x.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="624" LastActivityDate="2020-10-28T14:37:18.267" Title="Has the research into the apparent &quot;Pause&quot; in GMSTs produced a substantially better explanation?" Tags="|climate-change|climate|climate-models|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20396" PostTypeId="2" ParentId="15260" CreationDate="2020-10-28T18:50:36.777" Score="1" Body="&lt;p&gt;Some desal plants takes brackish water from under ground and treat it. YES it does cause problems with salinity, though the water used is often pumped back underground to be used again.&#xA;But desalination plants that take water from the sea have no effect on ground water, if anything they can be used to regenerate ground water by agreeing to donate certain percentage of the water produced for ground water replenishment.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-10-28T18:50:36.777" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20397" PostTypeId="2" ParentId="8392" CreationDate="2020-10-28T18:59:47.097" Score="0" Body="&lt;p&gt;Currently estimates show desalination plants there are 22,000 plants worldwide which produce about 142 million cubic meters (37+ Billion gallons) of fresh water per day. That has negligible impact on weather.&lt;/p&gt;&#xA;&lt;p&gt;The biggest detriment to desalination is ENERGY USE. Because Pumping water into the great Basin, The Great Basin and deserts of California are anywhere from 4000-6000 FEET above Sea level.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/0g6hC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0g6hC.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;A typical water pump's wattage can vary between 250 watts to 1,100 watts.&#xA;University of California Agriculture and natural resources dept; it takes an average (depending on pump efficiency) about two kilowatt-hours to pump an Acre-foot of water (325,851 gallons) one foot in elevation. But a Kilowatt hours worth of electricity in California costs 18 cents average. Sounds efficient? But that's 18,102 gallons per cent, NOW add elevation the &amp;quot;Great Basin&amp;quot; is over 6000 feet above sea level. NOW it takes six Megawatt-hours or 1,080 dollars worth of electricity to pump one Acre foot. The Carlsbad desalination plant in San diego county produces 150 Acre feet of water per day. Or 300 dollars per acre foot. California farmers pay an average of $70 per acre-foot to irrigate. It makes NO sense financially. California uses 38 Billion gallons of water per day....... Pumping sea water UP hill to accommodate weather modification would be so ridiculously expensive.&lt;/p&gt;&#xA;&lt;p&gt;If you really want to &amp;quot;humidify&amp;quot; California, BUILD nuclear plants, they use millions of gallons of water and emit millions of gallons in steam a day.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-10-28T18:59:47.097" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20398" PostTypeId="1" CreationDate="2020-10-28T23:54:20.610" Score="1" ViewCount="163" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/River_engineering#Channelization&quot; rel=&quot;nofollow noreferrer&quot;&gt;Channelization&lt;/a&gt; is when you straighten a river to make a shorter path from A to B. This makes the water flow faster, since the path is shorter but the volumetric flow rate of water must be the same (because it's receiving the same rate of water from the watershed).&lt;/p&gt;&#xA;&lt;p&gt;However, that wikipedia article also says,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Channelization has several predictable and negative effects. One of them is loss of wetlands.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;No citation and no explanation. I don't get it. Why would nearby wetlands be lost from this process? How could that happen?&lt;/p&gt;&#xA;" OwnerUserId="2733" LastActivityDate="2021-01-18T04:07:59.463" Title="Why would channelizing a river reduce any nearby wetlands?" Tags="|hydrology|rivers|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20399" PostTypeId="2" ParentId="20398" CreationDate="2020-10-29T01:58:02.363" Score="0" Body="&lt;p&gt;Length of Rivers determines rate of flow. When you straighten a river you increase it's flow rate and make it MORE prone to flooding downstream. Cities try to curb this by turning their rivers into huge drainage swaths (LA river) but ultimately it's pointless. Winding rivers desposit sediments and silt (and nutrients) on lands, those feed wetlands necessary soil amendments they otherwise could not obtain&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-10-29T01:58:02.363" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20401" PostTypeId="1" AcceptedAnswerId="20407" CreationDate="2020-10-29T13:28:12.247" Score="5" ViewCount="139" Body="&lt;p&gt;It is widely known (to the general audience, I'm not a climatologist) that global warming will let the desert climates migrate further away from the equator towards the poles, such that the South of Europe is becoming more and more desert-ish. (see e.g. &lt;a href=&quot;https://www.independent.co.uk/news/world/europe/global-warming-turning-europe-desert-2100-mediterranean-spain-portugal-italy-sicily-turkey-syria-fossil-fuels-a7383931.html&quot; rel=&quot;noreferrer&quot;&gt;this article&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;Now my question is: if the desert climates migrate; will the tropical climates also migrate / expand to a broader belt around the equator? Often, it is possible to live quite comfortably as a human in such a region.&lt;/p&gt;&#xA;" OwnerUserId="21293" LastActivityDate="2020-10-30T19:03:25.167" Title="Will global warming expand the tropical zone" Tags="|climate-change|desertification|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20402" PostTypeId="1" CreationDate="2020-10-29T19:41:02.867" Score="3" ViewCount="47" Body="&lt;p&gt;The two CF standard names platform_id and platform_name strike me as being redundantly similar. From their definition in the CF standard name table:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;platform_id:&lt;/strong&gt;&lt;br /&gt;&#xA;&lt;em&gt;alias&lt;/em&gt;: station_wmo_id&lt;br /&gt;&#xA;A variable with the standard name of platform_id contains strings which help to identify the platform from which an observation was made.&lt;br /&gt;&#xA;For example, this may be a WMO station identification number.&lt;br /&gt;&#xA;A &amp;quot;platform&amp;quot; is a structure or vehicle that serves as a base for mounting sensors. Platforms include, but are not limited to, satellites, aeroplanes, ships, buoys, instruments, ground stations, and masts.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;platform_name:&lt;/strong&gt;&lt;br /&gt;&#xA;&lt;em&gt;alias&lt;/em&gt;: station_description&lt;br /&gt;&#xA;A variable with the standard name of platform_name contains strings which help to identify the platform from which an observation was made.&lt;br /&gt;&#xA;For example, this may be a geographical place name such as &amp;quot;South Pole&amp;quot; or the name of a meteorological observing station.&lt;br /&gt;&#xA;A &amp;quot;platform&amp;quot; is a structure or vehicle that serves as a base for mounting sensors. Platforms include, but are not limited to, satellites, aeroplanes, ships, buoys, instruments, ground stations, and masts.&lt;/p&gt;&#xA;&lt;p&gt;Are there contexts where these are used interchangeably? Or conversely, where the distinction between them is quite distinct?&lt;/p&gt;&#xA;" OwnerUserId="14348" LastActivityDate="2020-10-29T19:41:02.867" Title="What is the difference between the CF standard_names `platform_id` and `platform_name`" Tags="|data-formats|netcdf|cf-metadata|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20403" PostTypeId="1" CreationDate="2020-10-30T05:39:59.770" Score="1" ViewCount="53" Body="&lt;p&gt;I am looking for a book or an article where I can find the Lamé parameters of Granite, any help would be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="21299" LastActivityDate="2020-10-30T05:39:59.770" Title="Lamé parameters of granite and similar rocks" Tags="|rocks|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20405" PostTypeId="1" AcceptedAnswerId="20408" CreationDate="2020-10-30T17:30:02.340" Score="2" ViewCount="50" Body="&lt;p&gt;What is the difference between a free forecast and a cycled model run?  &lt;a href=&quot;https://github.com/NOAA-EMC/global-workflow/wiki/Run-Global-Workflow#run-setup-scripts-to-generate-experiment&quot; rel=&quot;nofollow noreferrer&quot;&gt;This GFS wiki&lt;/a&gt; mentions both, but does not define them.&lt;/p&gt;&#xA;" OwnerUserId="12334" LastEditorUserId="12334" LastEditDate="2020-10-30T20:22:18.350" LastActivityDate="2020-10-30T20:39:38.703" Title="Free forecast vs cycled model runs" Tags="|models|atmosphere-modelling|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20406" PostTypeId="1" CreationDate="2020-10-30T16:46:52.127" Score="3" ViewCount="522" Body="&lt;p&gt;Silicon is often touted as the second most abundant element in the Earth's crust. However, this can be misleading when looking at the abundance of high purity silica needed for manufacturing semiconductor wafers.&lt;/p&gt;&#xA;&lt;p&gt;What purity level is required in naturally occurring silica in order to be used for manufacturing semiconductors? How abundant is it in the earth's crust?&lt;/p&gt;&#xA;" OwnerUserId="21304" OwnerDisplayName="gstudent" LastEditorUserId="2958" LastEditDate="2020-11-01T23:38:21.343" LastActivityDate="2021-10-01T20:15:42.527" Title="How abundant is high purity silica?" Tags="|geochemistry|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20407" PostTypeId="2" ParentId="20401" CreationDate="2020-10-30T19:03:25.167" Score="4" Body="&lt;p&gt;It depends on how you define the tropics. Strictly speaking, the tropics can be defined as the area between the tropic of capricorn and the tropic of cancer (23.5&lt;span class=&quot;math-container&quot;&gt;$^\circ$&lt;/span&gt;N/S respectively). This is because of the earth's axial tilt of 23.5&lt;span class=&quot;math-container&quot;&gt;$^\circ$&lt;/span&gt;. Since I don't think that the climate change will affect the axial tilt too much, I doubt it.&lt;/p&gt;&#xA;&lt;p&gt;However, if you define the tropics in terms of climate, probably. Since the &lt;a href=&quot;https://journals.ametsoc.org/jas/article/68/4/769/26993/Response-of-the-Hadley-Circulation-to-Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hadley cell is expected to expand with more greenhouse gases&lt;/a&gt;, it follows that the tropical weather that accompanies the Hadley cell should expand with it.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-10-30T19:03:25.167" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20408" PostTypeId="2" ParentId="20405" CreationDate="2020-10-30T20:39:38.703" Score="2" Body="&lt;p&gt;Cool, didn't realize that the GFS was on Github.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://github.com/NOAA-EMC/global-workflow/wiki/Run-Global-Workflow#view-experiment-output&quot; rel=&quot;nofollow noreferrer&quot;&gt;Looking on down the wiki&lt;/a&gt;, it seems like the &amp;quot;free-forecast&amp;quot; is associated with the deterministic model, while the &amp;quot;cycled&amp;quot; is associated with the Ensemble Kalman Filter. That is, the free-forecast is not constrained by data assimilation algorithms- it can just start from a restart file and go. A cycled run, however, needs multiple runs, as well as data.&lt;/p&gt;&#xA;&lt;p&gt;This is all speculation based on naming conventions. If you really want an answer, perhaps &lt;a href=&quot;https://github.com/NOAA-EMC/global-workflow/wiki&quot; rel=&quot;nofollow noreferrer&quot;&gt;asking the code developer&lt;/a&gt;?&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-10-30T20:39:38.703" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20411" PostTypeId="1" CreationDate="2020-10-31T19:57:11.240" Score="4" ViewCount="241" Body="&lt;p&gt;Often the graphs depicting the earth's historical temperature, the time axis extends well over couple of centuries. Also there are few that extends over thousands of years.&lt;/p&gt;&#xA;&lt;p&gt;I wonder to what degree the measurement inaccuracies are taken into account while using these charts to communicate the ongoing climate change. Its a valid question that older temperature measurement suffer a higher error compared to modern day's methods.&lt;/p&gt;&#xA;&lt;p&gt;Even the feared 2.5°C temperature rise over the industrial revolution time is a minute variation over centuries. To what degree has the climate models taken into account these measurement errors into account? (In short, the question is basically from a climate change sceptic that goes like - &amp;quot;Thermometers have gotten better and we are just measuring the true temperature and it's not that the world is warming up. So how can we accept climate change/global warming?&amp;quot;)&lt;/p&gt;&#xA;" OwnerUserId="21307" LastActivityDate="2020-11-02T14:45:04.170" Title="To what degree does historical measurement inaccuracies contribute to climate change models?" Tags="|climate-change|temperature|measurements|climate-models|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20412" PostTypeId="2" ParentId="20411" CreationDate="2020-10-31T20:32:36.560" Score="4" Body="&lt;p&gt;I would estimate 0%, as long as we are considering the same types of models. See, climate models and in the regard that you may think of observations. Climate models aren't really initialized on observations of the system, but rather on inputs/forcings and mean state.&lt;/p&gt;&#xA;&lt;p&gt;Observations of today's climate may validate the accuracy/tuneness of a climate model, but the types of observations used to run climate models may be different from what you expect. &lt;a href=&quot;https://en.wikipedia.org/wiki/Thermometer#History&quot; rel=&quot;nofollow noreferrer&quot;&gt;For example, the thermometer was invented either near 10 AD or in the 17th century&lt;/a&gt;, so it was obviously not a widespread invention then. Usually, those temperature measurements are taken as proxies, &lt;a href=&quot;https://en.wikipedia.org/wiki/Proxy_(climate)&quot; rel=&quot;nofollow noreferrer&quot;&gt;such as the amount of oxygen isotope or atmospheric composition in ice cores&lt;/a&gt;. So the answer to the climate skeptic is that it isn't just the temperature itself, but the modern day observations of temperature proxies that show past warming.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-10-31T20:32:36.560" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20413" PostTypeId="1" CreationDate="2020-11-01T02:14:46.223" Score="1" ViewCount="841" Body="&lt;p&gt;I've been thinking about how difficult it is to eliminate toxic chemical waste -- it usually needs high temperatures and pressures. So: would it be feasible (and maybe cheaper) to send it into the mantle or core of the world? &lt;br/&gt;&#xA;I thought about grinding &amp;amp; liquifying our junk and pumping it into a subduction zone off the California coast. But I don't know if that would work; after a million years it might pop up in a California hot springs.&lt;/p&gt;&#xA;&lt;p&gt;Edit: Instead of pumping junk &lt;em&gt;into&lt;/em&gt; a subduction zone, why not just drop the junk &lt;em&gt;onto&lt;/em&gt; the sea floor at a subduction zone? It would have to be resistant to ocean water, but other than that it would gradually be pulled below the crust. And presumably be neutralized by the hot high pressure.&lt;/p&gt;&#xA;" OwnerUserId="21308" LastEditorUserId="21308" LastEditDate="2020-12-06T04:19:46.273" LastActivityDate="2021-10-25T08:57:31.240" Title="Can garbage be sent into the (near-)center of the world?" Tags="|plate-tectonics|ecology|economic-geology|subduction|" AnswerCount="4" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20415" PostTypeId="2" ParentId="10614" CreationDate="2020-11-01T18:47:26.100" Score="0" Body="&lt;p&gt;All soil starts off as rock. Temperature, precipitation and wind affect it's rate of breakddown. And biological activity is what contributes to major soil building. Plants that thrive without soil (epiphytes, lithophytes) are often the first generation of plants. As they die, new ones take their place and the first layer of accumulated biomass builds to accommodate more sophisticated plants grow in this medium. Nitrogen fixing plants take advantage of atmospheric nitrogen; thus never deprived of an available source.&#xA;Atmosphere contributes WIND which can cause soil erosion if little plants exist to secure it.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-11-01T18:47:26.100" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20416" PostTypeId="2" ParentId="8838" CreationDate="2020-11-01T20:33:14.013" Score="-2" Body="&lt;p&gt;6000 years ago during the Holocene Climatic Optimum the Sahara desert was covered in lakes and vegetation. All this went away when the world cooled.&lt;a href=&quot;https://i.stack.imgur.com/ZgECS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZgECS.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-11-01T20:33:14.013" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20417" PostTypeId="1" CreationDate="2020-11-02T07:38:54.403" Score="1" ViewCount="26" Body="&lt;p&gt;I would like to know if there exist any python codes to generate a piper plot with trends such as pH, Hardness plotted inside the plots to see how the chemistry of the sample corresponds to such parameters.&#xA;Thank you in advance&lt;/p&gt;&#xA;" OwnerUserId="21311" LastEditorUserId="725" LastEditDate="2020-11-16T10:05:08.813" LastActivityDate="2020-11-16T10:05:19.177" Title="How to incorporate trends within a ternary diagram?" Tags="|software|python|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20419" PostTypeId="2" ParentId="20411" CreationDate="2020-11-02T10:10:09.733" Score="0" Body="&lt;p&gt;The graphs you mention, with temperatures extending for centuries or even millennia, are actually not measurements from thermometers. They are based on &lt;a href=&quot;https://en.wikipedia.org/wiki/Proxy_(climate)&quot; rel=&quot;nofollow noreferrer&quot;&gt;proxies&lt;/a&gt; such as tree rings or ice cores, from which temperature is &lt;em&gt;estimated&lt;/em&gt;, not &lt;em&gt;measured&lt;/em&gt;. Of course this estimate is based on some measurable variable (tree ring width, for example), which itself has an uncertainty, but this uncertainty does not vary with time. If you analyse tree rings from a 1000 years old tree, measurements of width (or wood density) will be as accurate on the oldest rings than on the more recent ones, as all will be accomplished with the same, modern method.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-11-02T10:10:09.733" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20420" PostTypeId="1" CreationDate="2020-11-02T11:27:46.903" Score="3" ViewCount="103" Body="&lt;p&gt;I should point out first that I don't know the first thing about environmental science, I study mathematics, and the reason I am asking this question is because I want to understand the processes behind climate change better. And, after hearing that methane is such a powerful greenhouse gas, it sounded weird to me that it was also produced during the process of producing biogas, so I basically want to understand how that process works and why the production of methane in it isn't harmful.&lt;/p&gt;&#xA;" OwnerUserId="21313" LastActivityDate="2020-11-03T02:58:35.020" Title="What part does methane play in the process of producing biogas?" Tags="|climate-change|greenhouse-gases|methane|biomass|energy|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20421" PostTypeId="1" AcceptedAnswerId="20441" CreationDate="2020-11-02T14:24:50.920" Score="1" ViewCount="63" Body="&lt;p&gt;From reading about &lt;a href=&quot;https://en.wikipedia.org/wiki/Cay&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cays on Wikipedia&lt;/a&gt; it seems they are formed from coral reefs covered with sand or gravel.  There are however some cays scattered around the world which are hundreds of feet off of sea level at high tide.  How did these cays form, or are they mis-classified islands?&lt;/p&gt;&#xA;" OwnerUserId="21314" LastEditorUserId="6" LastEditDate="2020-11-04T10:13:00.387" LastActivityDate="2020-11-05T03:40:44.340" Title="How are tall cays formed?" Tags="|geology|geography|geomorphology|islands|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20422" PostTypeId="2" ParentId="20411" CreationDate="2020-11-02T14:45:04.170" Score="2" Body="&lt;p&gt;&amp;quot;In short, the question is basically from a climate change sceptic that goes like - &amp;quot;Thermometers have gotten better and we are just measuring the true temperature and it's not that the world is warming up. So how can we accept climate change/global warming?&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;You could point them to the satellite datasets, which show that there has been significant warming since the late 1970s.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iTi8n.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iTi8n.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;(&lt;a href=&quot;https://www.woodfortrees.org/plot/rss/plot/uah5/plot/uah6/plot/none&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;You could point out that instrumental record has error bars that are published with the data that reflect the decrease in uncertainty over time, e.g.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QPB1K.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QPB1K.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;which makes it clear that the warming we have observed cannot be explained by the uncertainty.  The best group provide code and papers allowing any skeptic to check their methodology (although I can't find the link just at the moment).&lt;/p&gt;&#xA;&lt;p&gt;Similarly, the uncertainties of paleoclimate proxy reconstructions are not able to explain the current warming either (especially the rate at which it is happening).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QEDfP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QEDfP.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Often the diagrams shown in the media do not include the uncertainty, but generally the uncertainties are stated in the original data sources.&lt;/p&gt;&#xA;" OwnerUserId="624" LastActivityDate="2020-11-02T14:45:04.170" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20423" PostTypeId="2" ParentId="20420" CreationDate="2020-11-02T23:25:34.967" Score="1" Body="&lt;p&gt;As Jean-Marie Prival commented, methane &lt;em&gt;is&lt;/em&gt; the biogas (after removing impurites such as &lt;span class=&quot;math-container&quot;&gt;$H_2S$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt;).&lt;/p&gt;&#xA;&lt;p&gt;Biogas is renewable because &lt;a href=&quot;https://en.wikipedia.org/wiki/Biogas&quot; rel=&quot;nofollow noreferrer&quot;&gt;&amp;quot;From a carbon perspective, as much carbon dioxide is absorbed from the atmosphere in the growth of the primary bio-resource as is released, when the material is ultimately converted to energy.&amp;quot;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2020-11-02T23:25:34.967" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20424" PostTypeId="2" ParentId="20420" CreationDate="2020-11-03T02:58:35.020" Score="2" Body="&lt;p&gt;When you say produced, do you mean chemically made from another substance, or you do mean released into the atmosphere, or do you mean captured and stored?&lt;/p&gt;&#xA;&lt;p&gt;Methane, or CH4, is a biogas as it is gas biologically created by organisms. Methane is created in natural processes from which it may be immediately released into the atmosphere or on much slower time scales, such as millennia and more. Methane is also released in some artificial processes, such as the flaring on oil wells. Likewise, in petroleum processing facilities, methane can leak out in other ways than is intended. So, that is how it gets out, or is &amp;quot;produced&amp;quot; as a free gas.&lt;/p&gt;&#xA;&lt;p&gt;However, if you are asking if CH4 is produced chemically as a product of processing OTHER gases, then the answer is only a mild &amp;quot;sort of&amp;quot;. When natural gas from within the Earth is removed from the ground, it contains methane, propane and other gases that are separated into their components. However, most of the nat gas IS methane to begin with. So, saying it is &amp;quot;produced&amp;quot; is sort of true and easily misunderstood.&lt;/p&gt;&#xA;" OwnerUserId="7800" LastActivityDate="2020-11-03T02:58:35.020" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20425" PostTypeId="2" ParentId="8838" CreationDate="2020-11-03T03:05:22.780" Score="0" Body="&lt;p&gt;We should not expect to see expect to see historic examples of destructive climate warming. Volcanic eruptions can cause rapid, short lived regional and global cooling by introducing sulphate aerosols to the upper atmosphere and blocking and reflecting sunlight but there are no equivalent phenomena that trigger rapid, short lived warming.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2020-11-03T03:05:22.780" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20426" PostTypeId="2" ParentId="20413" CreationDate="2020-11-03T03:10:19.650" Score="8" Body="&lt;p&gt;No. In fact, I don't know why David Hammen didn't say that instead of commenting.&lt;/p&gt;&#xA;&lt;p&gt;The deepest hole that mankind ever dug was barely a scratch on the Earth's surface when you look at its size. They didn't even reach the mantle. The hole is only 12km deep, took about 20 years to create, and is still only 1/3 of the way to the mantle! Also, the hole is nothing through which you could dump garbage. It's only NINE inches in diameter.&lt;/p&gt;&#xA;&lt;p&gt;Have you wondered what it means to dump trash into the Earth? Trash takes up space. There are no known voids in the deep Earth. It is very dense. To make room for trash, first you would have to dig the IMMENSELY expensive hole. Doing this also wastes energy. Then, you would need to invent technology to dig out a massive space, working from inside a nine-inch hole that goes over 7 miles into the Earth's surface. How expensive would that be? Is it even possible to carve out a space in the Earth under that much pressure without it collapsing? Given that scientists have only managed to keep open a nine-inch hole, you can bet we currently don't have available technology to build any kind of void for trash, let alone a void big enough to hold enough trash to make more room on the surface.&lt;/p&gt;&#xA;&lt;p&gt;[Edit: Added 10/25/2021]&#xA;Just reviewing my comments on this site, I realized I had not mentioned that putting waster quite deep in the Earth may not be viable, but putting waste in a place where the Earth itself will drag the waste away from the surface is an option. In other words, put the waste into a subduction zone. Serious studies have been done on this. Unfortunately, even if the science and engineering for the idea seem sound, people are wary of this method because (a) whoever executes the plan could make mistakes and (b) the plan itself could be flawed, regardless of how many experts designed and vetted it&lt;/p&gt;&#xA;" OwnerUserId="7800" LastEditorUserId="7800" LastEditDate="2021-10-25T06:12:56.063" LastActivityDate="2021-10-25T06:12:56.063" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20427" PostTypeId="2" ParentId="20387" CreationDate="2020-11-03T03:42:18.063" Score="0" Body="&lt;p&gt;Your graph VALIDATES your perception of lightning happening at all times of the day. The graph ALSO shows that average frequency of lightning (well, thunder) is simply HIGHER during the mid-to-late afternoon. If you think that your local observations are contrary to this data, you would first need to diligently and accurately keep observing records. First, track thunder, not lighting. Lightning is perceived more easily at night. That is one key part.&lt;/p&gt;&#xA;&lt;p&gt;Now, since thunder is produced by lightning, the graph is effectively showing that lightning goes on day and night. Your question implies the graph somehow disagrees with the idea that lightning is occurring throughout the day and night. It does not, it only highlights the frequency changes.&lt;/p&gt;&#xA;&lt;p&gt;Second, you might have a biased memory. If you want to challenge this data, take accurate observations on your own. You might be surprised that what you thought you were observing was not actually what was happening. :-) Your local storms might not produce as much thunder (and thus lightning) as you think. Consider that massive tropical thunderstorms can produce more lightning than you can imagine, and this can happen day after day in the tropics. In the US, you can also get mesoscale systems that are blasting frequent lighting, but those don't occur as often as you may think. Sure, you might see thunderstorms every night for two weeks at some point in the summer if you live in the Deep South, but you won't see the same frequency of lightning day-after-day that you will see in some tropical storms. Consider that a complex that generates 800 lightning bolts is equivalent to TEN daily storms with 80 strikes. Then recall, the strikes you see at night don't count. You're counting thunder, so you can eliminate the bias of lightning being more visible at night.&lt;/p&gt;&#xA;&lt;p&gt;In the end, the sunlight is clearly a dominant factor in timing, as confirmed by the data.  Of course, the thunder is generally more frequent when the sun is providing the most energy for thundercloud development. Some days that energy is not utilized well (it is reflected by cloud cover, there is a massive inversion, the air is too dry, etc.). On average, though, that is when the greatest amount of lightning-generating cloud development will occur.&lt;/p&gt;&#xA;" OwnerUserId="7800" LastEditorUserId="7800" LastEditDate="2020-11-20T22:10:19.507" LastActivityDate="2020-11-20T22:10:19.507" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20428" PostTypeId="2" ParentId="20378" CreationDate="2020-11-03T04:45:36.357" Score="2" Body="&lt;p&gt;The currently most popular answer here completely fails to mention that your assumption would be impossible, as it would violate laws of thermodynamics, so I will offer my own answer.&lt;/p&gt;&#xA;&lt;p&gt;To the questioner, your assumption is that there would be a subterranean minimum of temperature, with the surface and the deep Earth being warmer. However, this &amp;quot;heat sandwich&amp;quot; cannot exist as it violate some pretty basic principles about energy transfer (thermodynamics).&lt;/p&gt;&#xA;&lt;p&gt;As you may know, when warmer matter is exposed to cooler matter, heat will conduct from the warmer matter to the cooler matter. This is in accordance with the 2nd law of Thermodynamics. So, the cool part of the &amp;quot;heat sandwich&amp;quot; would immediately start to warm up as it absorbed heat from the layers above it and below it. It would not be &amp;quot;in thermal equilibrium&amp;quot; with the other layers and eventually it would disappear. So, were you thinking there is a TEMPORARILY cool layer in the sandwich or were you thinking it has been there since the Earth formed? I assure you, based on heat conduction physics, any cool layer within the Earth would have warmed up long ago during the 4-1/2 BILLION years that the planet has existed. So, your assumption could only be right if the layer was recently put there. Is there a way that you propose to create a cool subterranean layer where none had existed?&lt;/p&gt;&#xA;&lt;p&gt;The ONLY way that cool layer could be created (or persist from the beginning of the Earth) is if it was somehow able to convert thermal energy into another form of energy. Thus, heat coming in from the outer layers of the sandwich (from above and below) would have to be continually converted into another form of energy (such as a change of chemistry or phase of matter). This process would technically not violate the law of conservation of energy, and it would still be a &amp;quot;sink&amp;quot; of heat energy. It would allow your cool layer to persist. HOWEVER...&lt;/p&gt;&#xA;&lt;p&gt;There is basically no such massive heat sink down where you thought this cool layer exists. So, unless you knew there was a subterranean cooling system in place, your own assumption of a cool layer was just that - an assumption without a robust physical basis. Did you have some reason to assume there was a subterranean cool layer in the Earth? Maybe you're thinking of how on a warm spring summer day, an excavator can dig into the Earth and expose some cool soil. If so, those temperature variations change daily and seasonally, but they don't show up in subterranean rock 100 feet below the soil.&lt;/p&gt;&#xA;&lt;p&gt;It is a fact that every exposed part of the planet fluctuates in temperature. So, on a microscale, when the surface warms, then technically there is a cooler layer below. However, that layer is temporary and will not be that deep. The surface can change temperature quickly due to effects of light radiation (heating), loss of heat due to infrared radiation (after sundown), evaporation or condensation of dew or frost, or conduction into any air or water that is contacting the surface. (FWIW, convection is not such a surface heat transfer mechanism, as it can only transport heat within a mobile phase of matter, not at the fixed soil interface.)&lt;/p&gt;&#xA;&lt;p&gt;There is one more mechanism affecting soil and even some rock temperatures, and that is the transport of heat energy (positive OR negative) due to the flow of liquid within the soil or rock. For example, cold rain water draining into a subterranean river can cool th rock it passed through. Still, in general, the Earth's surface typically changes temperature very slowly over time once you get roughly 10-50 feet down, depending on where you are and how much water is percolating through. The temperature profile below that depth remains steady, heating up as you go deeper.&lt;/p&gt;&#xA;&lt;p&gt;By the way, the reason the Earth is so warm in the interior, after having 4-1/2 billion years to cool off since it's formation, is that uranium in the Earth is decaying. This atomic decay releases heat. The atomic energy release is basically the same mechanism as in a nuclear fission reactor, but the reactions are going MUCH more slowly. Since the core of the Earth probably has extremely little uranium, that means the Earth's core is not generating heat through fission. However, core of the earth keeps as warm as it nowhere to LOSE its heat. (Technically, there are a couple of relatively very minor heat sources and sinks in the core, but I won't raise address them here.)&lt;/p&gt;&#xA;&lt;p&gt;Here is a graph of how soil and rock temperatures might change at a site:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://www.builditsolar.com/Projects/Cooling/amplitude-vs-depth.gif&quot; alt=&quot;graph of how soil and rock temperatures might change at a site.&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;(source: &lt;a href=&quot;https://www.builditsolar.com/Projects/Cooling/EarthTemperatures.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.builditsolar.com/Projects/Cooling/EarthTemperatures.htm&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="7800" LastEditorUserId="7800" LastEditDate="2020-11-03T04:52:46.680" LastActivityDate="2020-11-03T04:52:46.680" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20429" PostTypeId="2" ParentId="15754" CreationDate="2020-11-03T05:15:46.460" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Where am I wrong in my assumption about natural water distillation (i.e. is rain water not as clean as it should be in theory)?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Generally, rain water is pretty clean. That is not an issue. Plus, we treat ground water and reservoir/lake/river water, so we could easily treat rain water. What you really fail to miss is that ground water and reservoir/lake/river IS just rain water. It is the water from a LOT of rain. When it comes to water use, humanity is taking water faster out of the ground than the ground can collect it. Now, if the ground can't collect water fast enough, and the ground covers nearly all of the land (except buildings and bodies of water), then obviously we humans can't practically collect anymore rain water than the ground. So, as long we use up more ground water than the ground can &amp;quot;collect&amp;quot; due to rain fall, we're going to run out of water. Now, there are some technical ways we could collect water better than the ground (e.g., don't let it evaporate, don't let it runoff into unused rivers). However, there is no way we could get as much water as all the land on Earth collects!&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;Why don't we collect rain water (at least for plant watering, if it is not suitable for drinking)?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;We do collect rainwater. We normally collect rainwater when it is easier to collect it locally than to get it from where it naturally flows to. If you count dams, we hold back water and collect water that way so it doesn't flow too quickly to the ocean, where it becomes too salty to drink or use for irrigation. Some people also collect rainwater from their roof, while others just leave out an open barrel (that's not much of surface area for collecting rain).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;Theoretically: after an animal consumed some amount of water, say a glass, how long will it take, given that animal just urinated on the ground, for that water to go through water cycle and become ready for drinking again?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;That depends on if the urine is going eventually into a river, shallow groundwater only 50 feet (or less), or a subterranean aquifer a few thousand feet down. It can evaporate immediately from the ground or flow into a river and evaporate the same day. On the other hand, some groundwater percolates far down into the Earth into &amp;quot;aquifers&amp;quot;. We remove water from those using wells, and we say those aquifers &amp;quot;recharge&amp;quot; when more water moves into them.&lt;/p&gt;&#xA;&lt;p&gt;The famous Oglalla aquifer recharges at a rate of about 0.85 inches per year. That is, if we draw it down an inch in a year, it won't even fill up to where it was in the next year. How long it takes water to get to a specific level from the surface is affected by porosity and the amount of water already in the rock. Water can't flow when it is blocked by water, right? Also, much water also moves horizontally as well as vertically. So, asking how long it takes for water to go from X to Y directly below it would assume that water even follows that path. It might be that Y only gets water from a far-away location Z. So, I will pass on the &amp;quot;how long&amp;quot; part of the question. I will add, though, that some groundwater is tens of thousands of years old. There are 12,000 inches per thousand feet. If an aquifer is 3,000 feet below the surface, it is 36,000 inches down. If the aquifer recharges at 1 in/yr, then dividing the distance (36,000) by the speed (the average flow of 1 in/yr) give you the time of travel -&amp;gt; 36,000 years. Again, that is an idealized vertical drainage with no feedback mechanisms and constant flow rate. The situation is more complex than that, but that's how you can think about it. :-)&lt;/p&gt;&#xA;" OwnerUserId="7800" LastEditorUserId="7800" LastEditDate="2020-11-20T22:03:32.523" LastActivityDate="2020-11-20T22:03:32.523" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20430" PostTypeId="1" CreationDate="2020-11-03T09:41:48.263" Score="1" ViewCount="137" Body="&lt;p&gt;it's my first time to ask question here, thank you for your answer(if any:)&lt;/p&gt;&#xA;&lt;p&gt;So I need to download the ERA5 land daily data, and as I try to download it from the website, the progress bar always shows 0.0/26.2G. And as I tried to use the API code, the python shows error with   raise Exception(error)&lt;/p&gt;&#xA;&lt;p&gt;Exception:&lt;/p&gt;&#xA; &#xA;401 Authorization Required&#xA;&lt;h1&gt;401 Authorization Required&lt;/h1&gt;&#xA;&lt;hr&gt;nginx/1.16.1&#xA;&lt;p&gt;As I am using the MAC pro and the CONDA system, can anyone tells me how to solve this issue?&lt;/p&gt;&#xA;&lt;p&gt;Many thanks:)&lt;/p&gt;&#xA;" OwnerUserId="21316" LastActivityDate="2020-11-03T09:41:48.263" Title="Problem in downloading ERA5 data" Tags="|geophysics|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20432" PostTypeId="1" AcceptedAnswerId="20434" CreationDate="2020-11-03T12:14:45.943" Score="9" ViewCount="1006" Body="&lt;p&gt;The sea wasn't always salty. It's been getting saltier over millions of years as minerals dissolve.&lt;/p&gt;&#xA;&lt;p&gt;Is there a natural limit to this process, or the will the sea keep getting saltier forever?&lt;/p&gt;&#xA;&lt;p&gt;Is there a natural process which removes salt from the sea at a significant rate?&lt;/p&gt;&#xA;&lt;p&gt;How long would it take for the sea to get too salty to support life as we know it?&lt;/p&gt;&#xA;" OwnerUserId="770" LastActivityDate="2020-11-05T09:02:07.253" Title="Will the sea get saltier forever?" Tags="|geology|oceanography|geochemistry|mineralogy|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20433" PostTypeId="2" ParentId="20370" CreationDate="2020-11-03T18:25:33.150" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;...so how does it get from 1000 to 10,000 feet - what lifts CO2 up?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Hmm... how does it get to the mid-troposphere and higher?&lt;/p&gt;&#xA;&lt;p&gt;Well, first, to understand that one may find some helpful information in comments below the question. Second, it always helps to review our own assumptions.&lt;/p&gt;&#xA;&lt;p&gt;In the question, there's an implicit assumption that CO2 does not mix with the rest of the atmosphere at the molecular level. As it turns out, &lt;em&gt;it does!&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Also, the primary mixing mechanism in the troposphere takes place through &lt;em&gt;eddy diffusion, not molecular diffusion&lt;/em&gt;, and that's an important distinction. Storms and jet streams, convection, and turbulence (from storms and clouds down to the nearly molecular size) all contribute to mixing.&lt;/p&gt;&#xA;&lt;p&gt;As one goes higher in the atmosphere, the balance between the magnitude of eddy diffusion and molecular diffusion shifts. This happens above the tropopause.&lt;/p&gt;&#xA;" OwnerUserId="7800" LastEditorUserId="6031" LastEditDate="2020-11-21T01:35:20.483" LastActivityDate="2020-11-21T01:35:20.483" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20434" PostTypeId="2" ParentId="20432" CreationDate="2020-11-04T03:59:38.473" Score="5" Body="&lt;p&gt;No there are natural processes that remove salt as well.&lt;/p&gt;&#xA;&lt;p&gt;as sea level changes water gets trapped in basins and evaporates leaving the salt behind, this is where many of the salt formation on earth came from. whenever sea levels fall the salinity of the ocean drops. Tectonically isolated basin can remove salt in the same way. The process can even happen repeatedly in the same basin as sea level changes.&lt;/p&gt;&#xA;&lt;p&gt;There are biological processes that remove it as well the formation of shells and limestone remove some of the ocean salts.&lt;/p&gt;&#xA;&lt;p&gt;Can it increase yes, but it can also decrease, over earths history there have been saltier and less salty periods.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2020-11-05T03:20:36.487" LastActivityDate="2020-11-05T03:20:36.487" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20435" PostTypeId="1" CreationDate="2020-11-04T13:19:24.607" Score="1" ViewCount="63" Body="&lt;p&gt;As you might be aware, &lt;a href=&quot;https://www.goes-r.gov&quot; rel=&quot;nofollow noreferrer&quot;&gt;GOES-R&lt;/a&gt; is a very rich satellite system that delivers near real-time weather information for the globe. There are at least 16 channels reported (&lt;a href=&quot;https://www.star.nesdis.noaa.gov/GOES/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;this site&lt;/a&gt; is great for monitoring them).&lt;/p&gt;&#xA;&lt;p&gt;I am looking for an introductory course on satellite image for amateur weather analysis, ideally based on GOES-R. The training offered in &lt;a href=&quot;https://www.goes-r.gov/users/training/gsm.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;GOES-R website&lt;/a&gt; seems directed to practitioners. There are some guides around (NOAA site above, for instance, offers a &amp;quot;Quick Guide&amp;quot; for every channel, e.g. &lt;a href=&quot;https://www.star.nesdis.noaa.gov/GOES/documents/ABIQuickGuide_Band13.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Channel 13&lt;/a&gt; but that seems also too advanced for a novice to understand).&lt;/p&gt;&#xA;&lt;p&gt;Is anyone aware of an introductory course on satellite image interpretation? Naturally, I am looking for an online course, ideally free of charge. If based on GOES-R, the better.&lt;/p&gt;&#xA;" OwnerUserId="13541" LastActivityDate="2020-11-04T16:40:18.813" Title="Introductory course on interpreting GOES-R satellite images?" Tags="|weather-satellites|reference-request|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20436" PostTypeId="2" ParentId="20435" CreationDate="2020-11-04T16:40:18.813" Score="4" Body="&lt;p&gt;There are numerous short modules offered by UCAR's COMET/METED website: &lt;a href=&quot;https://www.meted.ucar.edu/training_detail.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.meted.ucar.edu/training_detail.php&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Modules specific to GOES-R include (but aren't limited to):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;GOES-R/JPSS test cases for &lt;a href=&quot;https://www.meted.ucar.edu/training_module.php?id=10041#.X6LYnIhKhqM&quot; rel=&quot;nofollow noreferrer&quot;&gt;convection initiation&lt;/a&gt; and &lt;a href=&quot;https://www.meted.ucar.edu/training_module.php?id=10034&quot; rel=&quot;nofollow noreferrer&quot;&gt;wildfires&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.meted.ucar.edu/training_module.php?id=1325#.X6LY_IhKhqM&quot; rel=&quot;nofollow noreferrer&quot;&gt;Advanced Baseline imager&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://meted.ucar.edu/training_module.php?id=1301#.X6LZJ4hKhqM&quot; rel=&quot;nofollow noreferrer&quot;&gt;A satellite foundational course&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;There are 19 courses with GOES-R in the title.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-11-04T16:40:18.813" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20437" PostTypeId="1" AcceptedAnswerId="20438" CreationDate="2020-11-04T22:09:38.450" Score="11" ViewCount="647" Body="&lt;p&gt;I've been researching Atmospheric Rossby waves but from the multiple sources I used they all seem to be in conflict. Some say Rossby waves are parcels of air moving from east to west due to the coriolis effect (which seems like a description for a jet stream) while others sources say it's the curving of the jet streams. I have a hard time understanding Atmospheric Rossby waves and how they affect the weather and climate.&lt;/p&gt;&#xA;" OwnerUserId="21320" LastActivityDate="2022-11-13T12:34:13.187" Title="What are Atmospheric Rossby Waves and how do they affect the weather?" Tags="|meteorology|atmosphere|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20438" PostTypeId="2" ParentId="20437" CreationDate="2020-11-04T23:18:38.670" Score="11" Body="&lt;p&gt;Where to start....&lt;/p&gt;&#xA;&lt;p&gt;If you take a look at midlatitude weather on any given day, you will find a pattern of upper tropospheric winds that look like this (source: &lt;a href=&quot;https://www.weather.gov/jetstream/longshort&quot; rel=&quot;noreferrer&quot;&gt;NWS&lt;/a&gt;):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EQJmw.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EQJmw.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Notice how it looks like a wave? These are called Rossby waves. You may imagine that the jet stream is imbedded in the ups and downs of these pressure contours. If we take a look at a typical winter storm (here is a &lt;a href=&quot;http://mp1.met.psu.edu/%7Efxg1/NARR/2003/us0301.php&quot; rel=&quot;noreferrer&quot;&gt;random storm from 2003&lt;/a&gt;): &lt;a href=&quot;https://i.stack.imgur.com/ZDAVj.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZDAVj.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Notice how wavy the 500 mb heights are? Don't they resemble the first figure?&lt;/p&gt;&#xA;&lt;p&gt;Now you might say &amp;quot;I've seen those things and they definitely move west to east.&amp;quot; This is true. That is because the prevailing wind is westerly (in the above examples). This can be shown in a &lt;a href=&quot;https://en.wikipedia.org/wiki/Rossby_wave#Mathematical_definitions&quot; rel=&quot;noreferrer&quot;&gt;mathematical analysis&lt;/a&gt;, though it should be noted that baroclinic Rossby waves (mostly in the midlatitudes) propagate slower than barotropic Rossby waves, which is what this analysis works on.&lt;/p&gt;&#xA;&lt;p&gt;I can probably into more extensive detail about Rossby waves, but I'll just end here.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-11-04T23:18:38.670" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20439" PostTypeId="2" ParentId="20156" CreationDate="2020-11-05T02:32:05.553" Score="3" Body="&lt;p&gt;I took a class once, and we had an approximate equation for an particle (&lt;a href=&quot;https://www.me.psu.edu/cimbala/me433/Exams/Equation_Sheet_ME433.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;equation sheet is still up&lt;/a&gt;):&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{d\vec{v}}{dt}=\frac{\rho_{particle}-\rho_{air}}{\rho_{particle}}\vec{g}-\frac{3\rho_{air}C_D}{4\rho_{particle}CD_{particle}}\vec{v}|\vec{v}|$$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; is density, &lt;span class=&quot;math-container&quot;&gt;$\vec{g}$&lt;/span&gt; is the gravity vector (usually &lt;span class=&quot;math-container&quot;&gt;$=g\hat{k}$&lt;/span&gt; but can be changed if the particle has a charge), &lt;span class=&quot;math-container&quot;&gt;$C_D$&lt;/span&gt; is the surface drag coefficient, &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; is the Cunningham correction factor, &lt;span class=&quot;math-container&quot;&gt;$\vec{v}$&lt;/span&gt; is the particle velocity, and &lt;span class=&quot;math-container&quot;&gt;$D_{particle}$&lt;/span&gt; is the aerodynamic diameter of the particle.&lt;/p&gt;&#xA;&lt;p&gt;Solving for &lt;span class=&quot;math-container&quot;&gt;$\frac{d\vec{v}}{dt}=0$&lt;/span&gt; to get the terminal velocity is one option. I can't remember if the above equation considers environmental motion. You can work through the other equations in the equation sheet and see that even getting a terminal velocity is complicated and requires an iterative method since &lt;span class=&quot;math-container&quot;&gt;$C_D=C_D(\vec{v})$&lt;/span&gt;. This might work for engineering purposes, but may not practical for atmospheric modeling.&lt;/p&gt;&#xA;&lt;p&gt;There is another take on this issue of deposition. One parameterization for dry deposition is the &lt;a href=&quot;http://www.smhi.se/sgn0106/if/biblioteket/rapporter_pdf/RMK_100.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;(see pgs. 6-9)&lt;/a&gt;: &lt;span class=&quot;math-container&quot;&gt;$$v_{deposition}=\frac{1}{r_a+r_b+r_a r_b v_s}+v_s$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$r_a=\frac{1}{ku_*}\left[\ln\left(\frac{z-d}{z_0}\right)-\Psi_h\left(\frac{z}{L}\right)\right]$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$v_s=\frac{D_p\rho_{particle}g}{18C\mu}$$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$v_s$&lt;/span&gt; is the settling velocity, &lt;span class=&quot;math-container&quot;&gt;$\mu$&lt;/span&gt; is the dynamic viscosity, &lt;span class=&quot;math-container&quot;&gt;$L$&lt;/span&gt; is the Monin-Obukhov length, &lt;span class=&quot;math-container&quot;&gt;$\Psi_h$&lt;/span&gt; is the integrated similarity/Businger-Dyer function for heat, &lt;span class=&quot;math-container&quot;&gt;$k$&lt;/span&gt; is the von-Karman constant, &lt;span class=&quot;math-container&quot;&gt;$z_0$&lt;/span&gt; is the roughness length, &lt;span class=&quot;math-container&quot;&gt;$d$&lt;/span&gt; is the displacement height, &lt;span class=&quot;math-container&quot;&gt;$u_*$&lt;/span&gt;  is the friction velocity, and &lt;span class=&quot;math-container&quot;&gt;$r_b$&lt;/span&gt; is the viscous  sub-layer resistance.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2020-11-05T02:49:26.947" LastActivityDate="2020-11-05T02:49:26.947" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20440" PostTypeId="1" AcceptedAnswerId="20537" CreationDate="2020-11-05T02:48:49.127" Score="3" ViewCount="212" Body="&lt;p&gt;The NASA Goddard science education page answer to &lt;a href=&quot;http://teacherlink.ed.usu.edu/tlnasa/reference/imaginedvd/files/imagine/docs/ask_astro/answers/980403c.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reading about Mars, I noticed that it has .03% of water vapor in it's atmosphere, and my question was if it has water vapor why doesn't it have precipitation?&lt;/a&gt; says&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Mars does have precipitation.&lt;/p&gt;&#xA;&lt;p&gt;[...]&lt;strong&gt;However, this precipitation most likely takes the form of frost, rather than rain or snow.&lt;/strong&gt; The ground is likely to be colder than the air (especially on cold clear nights), and so air hitting the ground cools and the water freezes to the ground as frost. Viking II (a Mars lander in the 1970's) saw frost on the ground some mornings.&lt;/p&gt;&#xA;&lt;p&gt;A part of the polar ice caps of Mars is made of precipitated water ice (the rest is made of carbon dioxide as 'dry ice').&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;However another educational page &lt;a href=&quot;https://www.scholastic.com/teachers/articles/teaching-content/precipitation-weather/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Precipitation (Weather)&lt;/a&gt; says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Precipitation in meteorology refers to all forms of liquid or solid water particles that form in the atmosphere and then fall to the earth's surface. Types of precipitation include hail, sleet, snow, rain, and drizzle. &lt;strong&gt;Frost and dew are not classified as precipitation because they form directly on solid surfaces.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Mars has polar ice caps and a 25.19° inclination similar to that of Earth's. We see the polar caps shrink and grow regularly with the seasons each year.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Questions:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Can we say that the changes in the polar ice caps is due to &amp;quot;frost&amp;quot;?&lt;/li&gt;&#xA;&lt;li&gt;Can we say that the changes in the polar ice caps is due to &amp;quot;precipitation&amp;quot;?&lt;/li&gt;&#xA;&lt;li&gt;Is there really precipitation on Mars? Does frost count?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2020-11-05T02:58:22.273" LastActivityDate="2021-03-17T00:09:09.923" Title="Is there really precipitation on Mars? Does frost count?" Tags="|precipitation|terminology|mars|water-vapour|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="20441" PostTypeId="2" ParentId="20421" CreationDate="2020-11-05T03:34:35.620" Score="2" Body="&lt;p&gt;its the same way atolls form, sea level changes and tectonic plates move while the corals keep growing up as the land sinks. Any spot high enough for coral to survive can slowly grow in this way. they can end up hundreds of meters above the sea floor by the slow gradual process of growing coral.&lt;/p&gt;&#xA;&lt;p&gt;I find a simple &lt;a href=&quot;https://www.youtube.com/watch?v=vrD1O5hex6Y&quot; rel=&quot;nofollow noreferrer&quot;&gt;animation&lt;/a&gt; makes it easier to follow.&lt;/p&gt;&#xA;&lt;p&gt;Cays are just trapped sand in the coral reef, the sand can come from the erosion of nearby  islands, volcanic, or even erosion of the coral itself. This is why most cays occur near other land masses or in volcanically active areas.&lt;/p&gt;&#xA;&lt;p&gt;Just as land can sink it can also rise, pushing those deposits high above the waterline, note these cays are very rare. Also note the parts far above the water are dead ancient corals not living ones, although there may be leaving coral around the base. there are ancient fossil corals in the Himalayas after all.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2020-11-05T03:40:44.340" LastActivityDate="2020-11-05T03:40:44.340" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20442" PostTypeId="2" ParentId="20432" CreationDate="2020-11-05T09:02:07.253" Score="4" Body="&lt;p&gt;@John has answered to the second question: &amp;quot;Is there a natural process which removes salt from the sea at a significant rate?&amp;quot; This is an answer to the first one: &amp;quot;Is there a natural limit to this process, or the will the sea keep getting saltier forever?&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Yes, there is a limit, sea water cannot keep getting saltier forever.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Sea water is a solution of water and salt, i.e., the salt is dissolved in the water. But solubility, the ability of a material to dissolve in another, has a limit called saturation. Once this limit is reached, the material cannot dissolve anymore and precipitate.&lt;/p&gt;&#xA;&lt;p&gt;Saturation of salt in water is &lt;a href=&quot;https://en.wikipedia.org/wiki/Saline_water&quot; rel=&quot;nofollow noreferrer&quot;&gt;357 g L&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt;&lt;/a&gt; (at 20 °C, it depends on temperature), about 10 times the current salinity of seawater. If you keep adding more salt to such water, it will not longer be able to dissolve but will instead precipitate at the bottom of the sea.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-11-05T09:02:07.253" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20443" PostTypeId="1" AcceptedAnswerId="20444" CreationDate="2020-11-05T23:29:04.217" Score="1" ViewCount="1262" Body="&lt;p&gt;Why does the annual temperature range get bigger where latitude is higher?&#xA;Is it because of the ocean currents?&#xA;Or is there any other factor that causes this situation?&lt;/p&gt;&#xA;" OwnerUserId="21325" LastActivityDate="2020-11-06T05:06:07.740" Title="Why does the annual temperature range get bigger where latitude is higher?" Tags="|meteorology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20444" PostTypeId="2" ParentId="20443" CreationDate="2020-11-06T05:06:07.740" Score="7" Body="&lt;p&gt;Welcome to the Earth Science Stack Exchange!&lt;/p&gt;&#xA;&lt;p&gt;The bigger temperature range is because of the wide difference in the length of daylight seen in the higher latitudes. Depending on how high you are talking about, there can times where there is no sun for a month and vice versa with constant sun. Because of this there will therefore be more time for warmth and cooling as the Sun (or lack thereof) is what drives the diurnal temperature change the most.&lt;/p&gt;&#xA;" OwnerUserId="13660" LastActivityDate="2020-11-06T05:06:07.740" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20445" PostTypeId="1" CreationDate="2020-11-07T21:33:56.947" Score="1" ViewCount="36" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eZbLY.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eZbLY.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Map 4 shows two dykes that have been offset by a vertical fault. In different coloured pencils, draw strike lines on each dyke.&#xA;(a) On a blank sheet of paper, use the strike lines that you have drawn to construct a fault plane (juxtaposition)&#xA;section that illustrates the movement on the fault. Take care to annotate the section fully.&#xA;(b) What is the magnitude of the slip vector? Your answer must agree with the section to get the marks.&#xA;(c) What is the magnitude and sense (sinistral or dextral) of the strike-slip component of the slip vector? The&#xA;magnitude must agree with the section to get the marks.&#xA;(d) What is the magnitude and sense (down to the east or down to the west) of the dip-slip component of the slip&#xA;vector? Your answer must agree with the section to get the marks.&#xA;(e) What is the plunge/plunge direction of the slip vector?&lt;/p&gt;&#xA;" OwnerUserId="21331" LastActivityDate="2020-11-07T21:33:56.947" Title="Structural geology" Tags="|geology|geography|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20446" PostTypeId="1" CreationDate="2020-11-08T00:09:11.683" Score="2" ViewCount="78" Body="&lt;p&gt;My understanding is that soapstone is talc (hydrated magnesium silicate) which has been metamorphically transformed. However, it is not clear to me how this transformation affects the talc.&lt;/p&gt;&#xA;&lt;p&gt;What is the difference between talc and soapstone?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2020-11-16T09:41:01.610" Title="How does metamorphism change talc into soapstone?" Tags="|mineralogy|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20448" PostTypeId="1" CreationDate="2020-11-08T13:00:58.017" Score="3" ViewCount="61" Body="&lt;p&gt;With minimal knowledge of meteorology I understand how a high pressure system might lead to an inversion that builds as a high becomes more established, but why doesn’t the subsidence layer ever reach the ground?&lt;/p&gt;&#xA;" OwnerUserId="21336" LastActivityDate="2020-11-08T13:00:58.017" Title="Subsidence Inversion" Tags="|meteorology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20452" PostTypeId="1" CreationDate="2020-11-09T07:08:39.110" Score="4" ViewCount="2711" Body="&lt;p&gt;The answer to &lt;a href=&quot;https://earthscience.stackexchange.com/a/2642/21139&quot;&gt;How many trees would I have to plant to solve Global Warming?&lt;/a&gt; demonstrates how unviable it would be to simply plant trees to counter climate change (we'd need to plant ~60 millions km&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt; of trees - that's 6 times the area of Australia!)&lt;/p&gt;&#xA;&lt;p&gt;But it's based on the assumption of trees absorbing just 5.9 kg of carbon dioxide per year, but after a quick google there seems to be other estimates many times higher than that.&lt;/p&gt;&#xA;&lt;p&gt;Question: how high can CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; absorption go - that is, what species of plant (or combination of species) absorbs the most CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; per square km, and what is that figure approximately?&lt;/p&gt;&#xA;&lt;p&gt;Assumptions:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Assume favourable circumstances i.e. the conditions the plant(s) most prefer&lt;/li&gt;&#xA;&lt;li&gt;If possible, assume &lt;em&gt;&lt;strong&gt;net&lt;/strong&gt;&lt;/em&gt; average absorption over the life of the plant to take into account differing absorption rates as the plant grows, as well as the 'net' part handling for &lt;a href=&quot;http://scienceline.ucsb.edu/getkey.php?key=826#:%7E:text=During%20their%20lifetimes%2C%20plants%20generally,released%20again%20into%20the%20atmosphere.&quot; rel=&quot;nofollow noreferrer&quot;&gt;plants releasing some carbon&lt;/a&gt; as they grow&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="21139" LastEditorUserId="21139" LastEditDate="2020-11-11T06:24:31.727" LastActivityDate="2023-11-22T19:07:43.167" Title="Which type of plant absorbs the most net carbon dioxide per year per square km?" Tags="|climate-change|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20454" PostTypeId="1" CreationDate="2020-11-09T16:17:13.687" Score="5" ViewCount="189" Body="&lt;p&gt;I am attempting to download the 2m temperature forecast from the GFS forecasts archived by AWS's open dataset archive. I am having some issues figuring out the feature name to search for in the file names in order to get the correct data. I am filtering for grib2 files and am getting file names such as &amp;quot;gfs.20201030/18/gfs.t18z.gtg.0p25.f003.grib2&amp;quot; but none of them contain any containing a temperature feature name? What feature name should I be looking for, or am I just doing this all wrong? I appreciate any help on this newbie issue, as I have spent a couple of days trying to figure it out coming from the GEFS Reforecasts and am still stumped.&lt;/p&gt;&#xA;" OwnerUserId="21342" LastActivityDate="2020-11-09T16:17:13.687" Title="How to download the GFS 2m Temperature data?" Tags="|weather-forecasting|gfs|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20455" PostTypeId="2" ParentId="2639" CreationDate="2020-11-09T17:34:12.500" Score="-1" Body="&lt;p&gt;None, except tropical young trees. Overall, trees are carbon neutral. Wood/biomass has to be geologically sequestered to store carbon in the long term. That requires a tree with&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;a long life span (sequoia, cypress, etc)&lt;/li&gt;&#xA;&lt;li&gt;and growing in swampy conditions (to hold the remnants in sediment)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="21028" LastEditorUserId="21448" LastEditDate="2020-12-04T09:53:38.617" LastActivityDate="2020-12-04T09:53:38.617" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20456" PostTypeId="1" CreationDate="2020-11-10T10:48:23.733" Score="4" ViewCount="54" Body="&lt;p&gt;In my specific case, I have worked with a data set from 2001 to 2018 which had to be split up in 2012 due to major updates in the data. Therefore, I am now dealing with a data set of 12 years (2001 to 2012) and a data set of 7 years (2012 to 2018). I have to predict how the climate in the given area is changing in the future (I have 17 models prepared).&lt;/p&gt;&#xA;&lt;p&gt;I used a pattern scaling approach to superpose changes in daily climate variables to North American Regional Re-analysis (NARR) aka. my data points. That means I would only use 7 years in the future to predict the climate changes for the latter part of my data set. Hence, not really climate as we normally would discard 7 years of weather data as being nothing near climate data.&lt;/p&gt;&#xA;&lt;p&gt;Now, the question is then, how would you compare future climate with the current climate on a temporal scale of only 12 years, let alone 7 years?&#xA;Can you somehow account for this?&lt;/p&gt;&#xA;&lt;p&gt;EDIT&#xA;I am looking into wildfire ignitions in western America based on so-called fire weather indices (Canadian fire weather indices (FWI)). I have previously been able to predict these with logistic regression for 2001-2012 and 2012-2018. Now, I would like to see, how this may be in future climate.&lt;/p&gt;&#xA;&lt;p&gt;Therefore, I gathered future predictions of FWI from 17 models at a 2.5-degree resolution. I then found the daily mean difference between the past (2001-2018) and the future (e.g. 2082-2099). I superposed these changes to the NARR, 0.5-degree resolution and assigned them to my ignitions. E.g. if the daily mean diff in temperature is 5 Kelvin for one pixel at day 150, and two ignitions occurred within this pixel on that given day, I would add the 5 K to the original temperature measured. Thereby, I have the structure of the NARR but with the mean difference of 17 models.&lt;/p&gt;&#xA;&lt;p&gt;This would be fairly easy if I would look into the 18 years as a whole. But, due to the major revision in 2012, I have now two datasets split as mentioned before.&lt;/p&gt;&#xA;" OwnerUserId="21345" LastEditorUserId="21345" LastEditDate="2020-11-10T13:03:45.010" LastActivityDate="2020-11-10T13:03:45.010" Title="How would you predict the future climate with only 7 years of interest?" Tags="|climate-change|models|geography|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20458" PostTypeId="2" ParentId="20452" CreationDate="2020-11-11T07:13:44.620" Score="3" Body="&lt;p&gt;I have no personal expertise in this matter, but performed a quick search of recent literature. From what I can tell, the interest in fast-growing plants is motivated primarily by the desire to maximize bioenergy production, &lt;strong&gt;not&lt;/strong&gt; as a means of carbon sequestration. The typical goal is therefore multiple harvests per year in favorable conditions, meaning any carbon removed from the atmosphere by these plants is returned back to the atmosphere in a matter of months. Two plants commonly mentioned are eucalyptus trees and elephant grass.&lt;/p&gt;&#xA;&lt;p&gt;Humbertode Jesus Eufrade Junior, et al., &amp;quot;Sustainable use of eucalypt biomass grown on short rotation coppice for bioenergy&amp;quot;, &lt;em&gt;Biomass and Bioenergy&lt;/em&gt;, Vol. 90, July 2016, pp. 15-21&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;According to the results obtained, the density planting and fertilization levels have a greater influence on the dry matter yield, energy yield, and nutrient exports. The higher density planting reaches mean values of 30.9 tonnes of dry matter per hectare&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Rafael Fiusa de Morais, et al., &amp;quot;Elephant grass genotypes for bioenergy production by direct biomass combustion&amp;quot;, &lt;em&gt;Pesq. agropec. bras.&lt;/em&gt;, Vol. 44, No.2, Feb. 2009&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The objective of this work was to evaluate elephant grass (&lt;em&gt;Pennisetum purpureum Schum.&lt;/em&gt;) genotypes for bioenergy production by direct biomass combustion. Five elephant grass genotypes grown in two different soil types, both of low fertility, were evaluated. [...] The dry matter yields ranged from 45 to 67 Mg ha&lt;sup&gt;-1&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;There are 100 hectares in a square kilometer, and one Mg is one metric ton (tonne), so the reported annual yields correspond to 3090 tonnes per square kilometer for eucalyptus, and up to 6700 tonnes per square kilometer for elephant grass. Obviously the dry mass of plants is not just composed of carbon. The &lt;a href=&quot;http://www.fao.org/forestry/17111/en/&quot; rel=&quot;nofollow noreferrer&quot;&gt;FAO&lt;/a&gt; provides this helpful data:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The carbon content of vegetation is surprisingly constant across a wide variety of tissue types and species. Schlesinger (1991) noted that carbon content of biomass is almost always found to be between 45 and 50% (by oven-dry mass).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Assuming 45% carbon content, this means eucalyptus trees can bind 1390 tonnes of carbon / km&lt;sup&gt;2&lt;/sup&gt; / year and elephant grass can bind 3015 tonnes of carbon / km&lt;sup&gt;2&lt;/sup&gt; / year. A CO&lt;sub&gt;2&lt;/sub&gt; molecule has atomic weight 44 while carbon has atomic weight 12, so the CO&lt;sub&gt;2&lt;/sub&gt; tonnage is the 3.66-fold of these numbers, that is ~5100 tonnes and ~11000 tonnes, respectively.&lt;/p&gt;&#xA;" OwnerUserId="5255" LastEditorUserId="2470" LastEditDate="2023-11-22T19:07:43.167" LastActivityDate="2023-11-22T19:07:43.167" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20459" PostTypeId="1" CreationDate="2020-11-11T07:41:35.777" Score="4" ViewCount="34" Body="&lt;p&gt;We're interested in purchasing a vacation lake house in the piedmont/foothills of North Carolina. In earlier summers there, when driving from the mountains home to lower (sub-1000ft) elevations,  I've noticed that one has a very distinct sense of descending into a noticeably &amp;quot;yucky&amp;quot; layer of elevated heat, humidity, and haze.  (It's actually visible from the right vantage, much as it sometimes is when landing in an airplane).&lt;/p&gt;&#xA;&lt;p&gt;I think it'd be very desirable for this vacation home to be above this layer. But I don't know how to figure out what the typical elevation of the top of the layer is.  I'm not even sure how to define the layer.&lt;/p&gt;&#xA;&lt;p&gt;So I seek advice on how to quantify what I mean by this &amp;quot;yucky&amp;quot; lower layer of the summer atmosphere, as well as how to determine what its elevation is.&lt;/p&gt;&#xA;" OwnerUserId="21351" LastActivityDate="2020-11-11T07:41:35.777" Title="what elevation is top of southeastern US summer humidity/haze layer?" Tags="|meteorology|atmosphere|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20460" PostTypeId="1" CreationDate="2020-11-11T10:41:51.523" Score="4" ViewCount="157" Body="&lt;p&gt;Good Day. We Received this map as practice for our Geology university module and I have no idea how to draw the strike lines where the different heights intersect the different rock types in order to draw the cross section as there are many different directions for the lines. Can anyone possibly assist in this regard?&lt;a href=&quot;https://i.stack.imgur.com/Gbqow.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Gbqow.png&quot; alt=&quot;The Map we received in here as a picture&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21352" LastEditorUserId="21352" LastEditDate="2020-11-11T11:11:28.613" LastActivityDate="2020-11-11T11:11:28.613" Title="How would one go about drawing the contour lines for this map in order to draw the cross section?" Tags="|geology|rocks|mapping|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20461" PostTypeId="1" CreationDate="2020-11-11T23:16:56.527" Score="3" ViewCount="73" Body="&lt;p&gt;Free-air gravity anomaly measurements from &lt;a href=&quot;https://www.nasa.gov/mission_pages/icebridge/instruments/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Operation Icebridge&lt;/a&gt; aircraft are described in &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0012821X20305914?via%3Dihub&quot; rel=&quot;nofollow noreferrer&quot;&gt;A fault-bounded palaeo-lake basin preserved beneath the Greenland Ice Sheet&lt;/a&gt; (open access).&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; These appear to be at least smooth to 1 mGal if not less. Standard gravity is nearly one million &lt;s&gt;Gal&lt;/s&gt; mGal, so these are part-per-million type acceleration measurements made inside an airplane. How does one do this? &lt;em&gt;How are mGal-smooth free-air gravity anomaly measurements made exactly on a presumably bumpy airplane ride?&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;A heck of a lot of averaging or damping and GPS and/or lidar/radar reconstruction of average height?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Fig. 7. Gravity and magnetic anomalies... (b) Gravity anomaly modelling. The open circles mark free-air gravity anomaly measurements along the profile (&lt;strong&gt;the gap at ∼50 km reflects a turn in the flight line, where gravity data are unavailable&lt;/strong&gt;), and the coloured lines denote the calculated gravity effect associated with the interfaces in our crustal model (panel c). The gravity effect of the topography contains a signal from both the ice surface and bed interfaces.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SlCtk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SlCtk.png&quot; alt=&quot;Fig. 7. Gravity and magnetic anomalies... from A fault-bounded palaeo-lake basin preserved beneath the Greenland Ice Sheet&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Popular press linking to this paper:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.sciencealert.com/ancient-lake-discovered-under-greenland-may-be-millions-of-years-old-scientists-say&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ancient Lake Discovered Under Greenland May Be Millions of Years Old, Scientists Say&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.livescience.com/ancient-lake-under-greenland-ice.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Primeval Greenland lake found buried beneath a mile-thick slab of ice&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2020-11-12T00:36:24.077" LastActivityDate="2021-01-17T04:09:44.757" Title="How are mGal-smooth free-air gravity anomaly measurements made exactly? (tiny variations of acceleration on a bumpy airplane ride)" Tags="|gravity|ice-sheets|topography|greenland|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="20462" PostTypeId="1" CreationDate="2020-11-12T02:36:53.140" Score="1" ViewCount="63" Body="&lt;p&gt;We are very confused by this water body. This is called &amp;quot;Carolina Lake&amp;quot; however other suggests that it is not a Lake but a cove. Other say it is a tidal creek for it is influenced by tide. It was already explored beneath and found to have spring underneath (head of the sperm-like channel). It flows to the ocean 9 km away. What are your thoughts? It is a lake, cove or spring or tidal creek?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gqn9T.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gqn9T.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21355" LastActivityDate="2020-11-12T20:18:02.123" Title="Is it a Lake, Cove, Tidal Creek or a Spring?" Tags="|geology|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20463" PostTypeId="1" AcceptedAnswerId="20469" CreationDate="2020-11-12T18:52:41.893" Score="10" ViewCount="400" Body="&lt;p&gt;Dear earth science community,&lt;/p&gt;&#xA;&lt;p&gt;I am seeking a language to modernize a large Fortran project that works with geospatial NetCDF files.&#xA;The requirements for this language include:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A rock-solid NetCDF library (we do not want to reinvent the wheel).&lt;/li&gt;&#xA;&lt;li&gt;Excellent support for vectors and matrices (e.g. via operator overloading or something similar).&lt;/li&gt;&#xA;&lt;li&gt;Native performance is needed (compiled or JIT-compiled).&lt;/li&gt;&#xA;&lt;li&gt;Must be open-source.&lt;/li&gt;&#xA;&lt;li&gt;Ideally, simple bindings with Fortran (not a strict requirement).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;code&gt;Python&lt;/code&gt; +&lt;code&gt;numpy&lt;/code&gt; isn't really an option because of customized number-crunching with native performance.&#xA;Even if &lt;code&gt;numpy&lt;/code&gt; is implemented in C, the project includes custom algorithms that operate on matrices, and we do not want to write those in C.&#xA;I know that Python &lt;em&gt;could&lt;/em&gt; be optimized by calling into C or Fortran, but I just don't think that such optimization is going to happen with our team. Therefore, I am seeking a language that is &amp;quot;fast by default&amp;quot;. &lt;code&gt;Julia&lt;/code&gt; seems to deliver much better on this &amp;quot;fast by default&amp;quot; promise, whereas Python is more like &amp;quot;fast if you have the right optimizations in place&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;Matlab&lt;/code&gt; is a non-starter because of its proprietary license.&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;C&lt;/code&gt; is a non-starter because it does almost nothing to &amp;quot;modernize&amp;quot; a Fortran codebase.&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;Go&lt;/code&gt; is probably not sufficiently well-established for scientific computing?&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;Julia&lt;/code&gt; could be a promising option because it combines the ease of Python with native performance.&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;Kotlin&lt;/code&gt; might be interesting because it combines the strength of the JVM with the possibility to compile to native code.&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;Swift&lt;/code&gt; would be a great language, but I am not sure whether it is sufficiently mature for my targeted domain.&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;C++20&lt;/code&gt; and &lt;code&gt;Rust&lt;/code&gt; are additional options that might be interesting, but I fear the complexity of those languages (remember that this is for earth scientists, not computer scientists).&lt;/p&gt;&#xA;&lt;p&gt;Which options would you prefer for a gradual Fortran replacement with NetCDF files?&lt;/p&gt;&#xA;" OwnerUserId="21358" LastEditorUserId="725" LastEditDate="2020-11-16T09:43:24.063" LastActivityDate="2023-09-22T19:54:54.613" Title="Language to modernize a scientific Fortran codebase" Tags="|software|netcdf|" AnswerCount="4" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="20465" PostTypeId="2" ParentId="20463" CreationDate="2020-11-12T22:14:15.680" Score="1" Body="&lt;p&gt;Right now, I think that &lt;code&gt;Julia&lt;/code&gt; makes the cut, because it provides a great tradeoff between &amp;quot;fast scripting&amp;quot; and &amp;quot;high-performance scientific computing&amp;quot;.&#xA;But I am willing to hear other people's opinions, perhaps I have overlooked something.&lt;/p&gt;&#xA;" OwnerUserId="21358" LastActivityDate="2020-11-12T22:14:15.680" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20466" PostTypeId="2" ParentId="20463" CreationDate="2020-11-12T22:51:43.337" Score="8" Body="&lt;p&gt;As a former Fortran programmer I did a small online review several weeks ago into current trends for scientific programming.&lt;/p&gt;&#xA;&lt;p&gt;To begin with, despite its age and its sometimes archaic style of programming, because of its huge legacy, Fortran isn't being directed to the trash can in a hurry. It's going to be used for a long time to come.&lt;/p&gt;&#xA;&lt;p&gt;Like you, others have been looking for an alternative to start the move away from Fortran.&lt;/p&gt;&#xA;&lt;p&gt;Though very popular, Python is very &lt;strong&gt;slow&lt;/strong&gt; when executing programs. The speed of Fortran is another reason why it is still being used.&lt;/p&gt;&#xA;&lt;p&gt;For astronomical and physics applications, I've seen a number of references state a preference for initially teaching students Fortran but when they get more experienced in their field exposing them to C++.&lt;/p&gt;&#xA;&lt;p&gt;This comment from 2013, from a &lt;a href=&quot;https://www.physicsforums.com/threads/best-programming-language-for-physics.719723/&quot; rel=&quot;noreferrer&quot;&gt;Physics forum&lt;/a&gt; encapsulates the general ideas I seen:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The older guys use fortran and c++. The younger people use python,java,and c++.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;As with your answer, I think if Julia was more widely used it could have the potential to replace Fortran and possibly Python for scientific computing.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-11-12T22:51:43.337" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20467" PostTypeId="2" ParentId="20446" CreationDate="2020-11-13T00:47:57.647" Score="4" Body="&lt;p&gt;Soapstone is a form of talc. It is basically talc plus other minerals, such as micas, chlorite and amphiboles, depending on the initial rocks that were metamorphosed. Soapstone is also called a &lt;a href=&quot;https://geologyscience.com/rocks/soapstone/&quot; rel=&quot;nofollow noreferrer&quot;&gt;talc-schist&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Soapstone&quot; rel=&quot;nofollow noreferrer&quot;&gt;Soapstone&lt;/a&gt; is formed by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Metamorphism&quot; rel=&quot;nofollow noreferrer&quot;&gt;metamorphism&lt;/a&gt; of &lt;a href=&quot;https://en.wikipedia.org/wiki/Ultramafic_rock&quot; rel=&quot;nofollow noreferrer&quot;&gt;ultramafic&lt;/a&gt; protoliths, such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Dunite&quot; rel=&quot;nofollow noreferrer&quot;&gt;dunite&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Serpentinite&quot; rel=&quot;nofollow noreferrer&quot;&gt;serpentinite&lt;/a&gt; and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Metasomatism&quot; rel=&quot;nofollow noreferrer&quot;&gt;metasomatism&lt;/a&gt; of siliceous &lt;a href=&quot;https://en.wikipedia.org/wiki/Dolomite_(rock)&quot; rel=&quot;nofollow noreferrer&quot;&gt;dolomites&lt;/a&gt;. The metamorphism occurs in the regions where tectonic plates are present, where the rocks are subjected to heat and pressure, with flowing liquids, but without melting. &lt;a href=&quot;https://www.thoughtco.com/metamorphic-rock-types-4122981&quot; rel=&quot;nofollow noreferrer&quot;&gt;Soapstone&lt;/a&gt; is derived from &lt;a href=&quot;https://geologyscience.com/applied-geology/mining-geology/hydrothermal-alteration/&quot; rel=&quot;nofollow noreferrer&quot;&gt;hydrothemal alteration&lt;/a&gt; of &lt;a href=&quot;https://en.wikipedia.org/wiki/Peridotite&quot; rel=&quot;nofollow noreferrer&quot;&gt;peridotite&lt;/a&gt; and related ultramafic rocks.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-11-13T00:47:57.647" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20468" PostTypeId="1" CreationDate="2020-11-13T22:38:15.807" Score="1" ViewCount="66" Body="&lt;p&gt;I am trying to read in a file from &lt;code&gt;https://nomads.ncep.noaa.gov&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;I can read all multigrid files like &lt;a href=&quot;https://nomads.ncep.noaa.gov/pub/data/nccf/com/wave/prod/multi_1.20201113/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;but my script fails to read files from other links that are supposed to be Grib files&#xA;such as files from &lt;a href=&quot;https://nomads.ncep.noaa.gov/pub/data/nccf/com/estofs/prod/estofs_pac.20201113/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;&#xA;and fails with the error below&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;Exception has occurred: exceptions.ValueError&#xA;no matches found&#xA;  File &amp;quot;/buio/buio/pygrib.pyx&amp;quot;, line 610, in pygrib.open.select&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;or from &lt;a href=&quot;http://www.globalmarinenet.com/free-grib-file-downloads/#download&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I use &lt;a href=&quot;https://polar.ncep.noaa.gov/waves/examples/usingpython.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; python script to read the files.&#xA;I guess the format must be different?&lt;/p&gt;&#xA;" OwnerUserId="14963" LastActivityDate="2020-11-13T22:38:15.807" Title="Can not open Grib files from Nomands" Tags="|oceanography|python|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20469" PostTypeId="2" ParentId="20463" CreationDate="2020-11-14T02:50:59.073" Score="12" Body="&lt;p&gt;The modern language you are looking for is called modern Fortran 2018. Fortran 2008 and 2018 have everything a numerical computing project would need and so many features that many other languages mentioned here lack (including extremely pleasant array-syntax which has inspired all other languages such as MATLAB, Python, R, Julia, ..., even C++ numerical libraries). It is the only language that has native built-in parallelism and is the only language, along with C, for which the official MPI parallelism standard is released. It has also excellent vendor support for GPU parallel computing and as I heard in SC18, some vendors like NVIDIA/PGI have already started implementing the native parallelism features of Fortran via GPUs.&lt;/p&gt;&#xA;&lt;p&gt;Modern Fortran is a high-level language comparable to MATLAB and Python, yet 100-500 times faster than both (&lt;a href=&quot;https://modelingguru.nasa.gov/docs/DOC-2783&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://modelingguru.nasa.gov/docs/DOC-2783&lt;/a&gt;). Using Coarray Fortran you can seamlessly parallelize your code with minimal effort to run it from your laptop to the largest supercomputers in the world. No other language has such capability at the moment. Fortran is also the only language that has all levels of parallelism, from instruction level to vectorized, concurrent, and coarray-distributed parallel computing. If such features are not considered &amp;quot;modern&amp;quot;, perhaps &amp;quot;post-modern&amp;quot; would be a better description.&lt;/p&gt;&#xA;&lt;p&gt;Fortran has been a reliable lasting language for almost 3 quarters of a century and has excellent highly-optimized compiler support (Intel, GNU, NAG, IBM, PGI/NVIDIA, ...). If you want to write code that lasts decades, then port your FORTRAN77 code to modern Fortran with minimal effort and save yourself time, energy, money, and computational power.&lt;/p&gt;&#xA;&lt;p&gt;A good start with modern parallel object-oriented Fortran is &amp;quot;Modern Fortran Explained: Incorporating Fortran 2018&amp;quot; by Metcalf et al.&lt;/p&gt;&#xA;&lt;p&gt;If you decide to port your code effortlessly to modern Fortran, you can also get help from the official Fortran language website &lt;a href=&quot;https://fortran-lang.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://fortran-lang.org/&lt;/a&gt; and the community of programmers on Fortran discourse: &lt;a href=&quot;https://fortran-lang.discourse.group/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://fortran-lang.discourse.group/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Update Nov 17, 2020&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Just yesterday &lt;a href=&quot;https://developer.nvidia.com/blog/accelerating-fortran-do-concurrent-with-gpus-and-the-nvidia-hpc-sdk/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NVIDIA released a news post&lt;/a&gt; on its GPU implementation of the concurrent features of Fortran 2008 / 2018. Users can now write code in pure modern Fortran and let the compiler automatically offload it to GPUs for thousands-way parallelism.&lt;/p&gt;&#xA;&lt;p&gt;What is the relevance and importance of this achievement? The &lt;strong&gt;same Fortran code&lt;/strong&gt; that a user writes can now be parallelized via GPUs, distributed CPUs, OpenMP threads, or auto-parallelization features of the Fortran compiler depending on the user's platform and compiler choice. All of that complexity is hidden from the user. No need for preprocessing and conditional compilations anymore. This further enhances the excellent existing portability of Fortran programs across platforms and architectures.&lt;/p&gt;&#xA;" OwnerUserId="21361" LastEditorUserId="21361" LastEditDate="2020-11-18T04:29:46.157" LastActivityDate="2020-11-18T04:29:46.157" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20470" PostTypeId="2" ParentId="16977" CreationDate="2020-11-14T06:56:06.293" Score="0" Body="&lt;p&gt;Styrofoam maybe better for the environment than even paper.&lt;/p&gt;&#xA;&lt;p&gt;Plastic uses many chemical to create and recycling plastic causes more emissions as it is trucked then shipped to third world countries then more energy is used to recycle it.&lt;/p&gt;&#xA;&lt;p&gt;Even paper cups or plates use more energy as most are coated with a thin layer of plastic as well paper products in most cases use chemicals to make into pulp and then bleach to make them white.&lt;/p&gt;&#xA;&lt;p&gt;Styrofoam might even be less harmful than reusable porcelain or glass dishes from resourcing materials and shipping  they also need to be washed using chemicals and hot water.&lt;/p&gt;&#xA;&lt;p&gt;Styrofoam on the other hand saves energy as an insulator for hot coffee instead of double cupping a paper cup and also when it is put into the land fill it will not produce methane gas like paper and can be locally disposed of actually helping the environment.&lt;/p&gt;&#xA;&lt;p&gt;Also Styrofoam can actually be recycled and turned back into oils though there is just not enough programs to manage recycling Styrofoam also recycling anything causes energy to be used again polluting the environment.&lt;/p&gt;&#xA;&lt;p&gt;So what is the answer of what to do ?&lt;/p&gt;&#xA;&lt;p&gt;Easy just blame all the problems on single use products like Styrofoam and plastic straws instead of on human consumption and the uncontrolled population explosion of uneducated morons having morons.&lt;/p&gt;&#xA;" OwnerUserId="21363" LastEditorUserId="21363" LastEditDate="2020-11-14T07:01:07.360" LastActivityDate="2020-11-14T07:01:07.360" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20471" PostTypeId="1" CreationDate="2020-11-14T19:57:28.790" Score="1" ViewCount="50" Body="&lt;p&gt;I'm doing a project and looking at one of my scholarly resources, it says that&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The carbon footprint per kilogram protein of plant-based&#xA;substitutes was found in the range of 6–17 carbon dioxide equivalent (CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;-eq) kg&lt;span class=&quot;math-container&quot;&gt;$^{−1}$&lt;/span&gt;...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I want to compare it to the greenhouse gas emissions to a typical passenger vehicle, which is about 4.6 metric tons of carbon dioxide per year according to the &lt;a href=&quot;https://www.epa.gov/greenvehicles/greenhouse-gas-emissions-typical-passenger-vehicle&quot; rel=&quot;nofollow noreferrer&quot;&gt;EPA&lt;/a&gt;. But I have no idea what (CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;-eq) kg&lt;span class=&quot;math-container&quot;&gt;$^{−1}$&lt;/span&gt; means.&lt;/p&gt;&#xA;" OwnerUserId="21365" LastActivityDate="2020-11-14T19:57:28.790" Title="How would I compare (CO$_2$-eq) kg$^{−1}$ with metric tons?" Tags="|measurements|co2|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20474" PostTypeId="2" ParentId="2592" CreationDate="2020-11-15T17:42:55.740" Score="0" Body="&lt;p&gt;Bayesloc, according to the keywords &lt;strong&gt;nuclear explosion monitoring&lt;/strong&gt; in its URL &lt;a href=&quot;https://www-gs.llnl.gov/nuclear-threat-reduction/nuclear-explosion-monitoring/bayesloc&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www-gs.llnl.gov/nuclear-threat-reduction/nuclear-explosion-monitoring/bayesloc&lt;/a&gt;, seems exactly the software you can use to get an estimation of the uncertainties in the location of the event.&lt;/p&gt;&#xA;&lt;p&gt;You can find a review of available software in this article:&lt;/p&gt;&#xA;&lt;p&gt;KARASÖZEN, Ezgi and KARASÖZEN, Bülent. &lt;em&gt;Earthquake location methods.&lt;/em&gt; GEM - International Journal on Geomathematics. December 2020. Vol. 11, no. 1, p. 13.&lt;/p&gt;&#xA;" OwnerUserId="7545" LastActivityDate="2020-11-15T17:42:55.740" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20475" PostTypeId="1" AcceptedAnswerId="20479" CreationDate="2020-11-15T19:42:02.117" Score="4" ViewCount="186" Body="&lt;p&gt;Are any instruments today or at the time of the creation of the Panama canal capable of detecting a reduction in sea level from the creation of it? Given the size of the canal in comparison to the ocean I'm not sure that we have anything with the precision needed to measure this but I was curious if it was recorded or when the second and third lanes were added if it was recorded.&lt;/p&gt;&#xA;" OwnerUserId="21368" LastActivityDate="2020-11-18T04:52:00.077" Title="Did we ever record a reduction in sea level when the Panama canal was constructed?" Tags="|sea-level|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20476" PostTypeId="2" ParentId="20475" CreationDate="2020-11-16T09:38:52.317" Score="3" Body="&lt;p&gt;Since the Panama Canal isn't directly connected to the ocean and the water is overwhelmingly above the ocean sea surface, there was no reduction in sea level. See diagram:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WWDDb.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WWDDb.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-11-16T09:38:52.317" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20477" PostTypeId="2" ParentId="20446" CreationDate="2020-11-16T09:41:01.610" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;My understanding is that soapstone is talc (hydrated magnesium silicate) which has been metamorphically transformed&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Not quite. Soapstone is talc-rich rock. The way you put, you had talc to begin with, then it was metamorphosed, and something happened to the talc to transform it into soapstone. This is not accurate.&lt;/p&gt;&#xA;&lt;p&gt;You had something else to begin with (see Fred's answer), and it was transformed into talc-containing soapstone during metamorphism.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-11-16T09:41:01.610" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20478" PostTypeId="2" ParentId="20406" CreationDate="2020-11-16T10:17:44.403" Score="3" Body="&lt;p&gt;Quoting from this paper: Haus R., Prinz S., Priess C. (2012) Assessment of High Purity Quartz Resources. In: Götze J., Möckel R. (eds) Quartz: Deposits, Mineralogy and Analytics. Springer Geology. Springer, Berlin, Heidelberg. &lt;a href=&quot;https://doi.org/10.1007/978-3-642-22161-3_2&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1007/978-3-642-22161-3_2&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;What purity level is required in naturally occurring silica in order to be used for manufacturing semiconductors?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;As high as possible.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;...high purity quartz with total impurity levels less than 20 ppm...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;20 ppm means that the silica has to be 99.998% pure. It is extremely hard to find silica that pure in nature.&lt;/p&gt;&#xA;&lt;p&gt;More specifically:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Specific requirements as to tolerable limiting values differ from&#xA;industry to industry. In the lamp tubing and optics industries&#xA;aluminium content in the refined quartz concentrate should not exceed&#xA;20 ppm, other metals should be less than 1 ppm, and total impurities&#xA;less than 30 ppm. For semiconductor base materials and crucibles&#xA;aluminium content should be even lower, specified to less than 10 ppm,&#xA;other metals less than 0.1 ppm, and total impurities not to exceed 15&#xA;ppm.&lt;/p&gt;&#xA;&lt;p&gt;Feedstock for solar silicon used in the photovoltaic industry should&#xA;generally have boron and phosphorus contents in the sub-ppm range&#xA;since these elements are most difficult to remove and negatively&#xA;affect the performance of the solar cells (Geerligs et al. 2002).&lt;/p&gt;&#xA;&lt;p&gt;For microelectronics applications, e.g. in epoxy moulding compounds,&#xA;uranium and thorium, both responsible for soft errors by alpha&#xA;radiation, should be less than 2 ppb, and in low alpha applications,&#xA;even less than 0.5 ppb.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-11-16T10:17:44.403" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20479" PostTypeId="2" ParentId="20475" CreationDate="2020-11-16T19:11:47.590" Score="6" Body="&lt;p&gt;It's important to note that major man-made navigational canals &lt;a href=&quot;https://www.britannica.com/technology/canal-waterway/United-States#ref72494&quot; rel=&quot;nofollow noreferrer&quot;&gt;often&lt;/a&gt; are often routed so that only a smaller bit of new waterways is dug; they are typically made by connecting existing waterways with smaller cut\cuts across higher mountainous areas, plus shortcuts in any place where straightening the route saves significantly.&lt;/p&gt;&#xA;&lt;p&gt;It seems hard to find detailed construction maps (unfortunate!)  But here is a map of the area before the canal was made from the &lt;a href=&quot;https://etc.usf.edu/maps/galleries/us/panamacanalzone/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;USF historic maps archive&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vchKn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vchKn.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Comparing that to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Panama_Canal&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; map of the Canal shows two main areas of new waterway creation&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8RtRB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8RtRB.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, the largest creation on the map appears to be the expanse of &lt;a href=&quot;https://en.wikipedia.org/wiki/Gatun_Lake&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gatun Lake&lt;/a&gt; created by damming the river to create a wider channel (with other connected benefits like power and water storage).  Damming rivers is of course a widespread practice around the world for purposes including water regulation, power generation and agriculture.&lt;/p&gt;&#xA;&lt;p&gt;Looking at rough estimates of water changes (hopefully with no errors!):&lt;br /&gt;&#xA;&lt;sup&gt;&lt;sub&gt;Note these use the US\UK &lt;a href=&quot;https://en.wikipedia.org/wiki/Billion&quot; rel=&quot;nofollow noreferrer&quot;&gt;definitions&lt;/a&gt; of billion as &lt;span class=&quot;math-container&quot;&gt;$10^9$&lt;/span&gt; and trillion as &lt;span class=&quot;math-container&quot;&gt;$10^{12}$&lt;/span&gt;.  Replace billion with millard and trillion with billion in other regions.&lt;/sub&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Culebra_Cut&quot; rel=&quot;nofollow noreferrer&quot;&gt;Culebra Cut&lt;/a&gt; &amp;quot;has an average depth of about 43 feet (13 metres) and extends some 8 miles (13 km) to the Pedro Miguel Locks&amp;quot; and &amp;quot;throughout its length the canal has a minimum bottom width of 500 feet (150 metres)&amp;quot; &lt;a href=&quot;http://Throughout%20its%20length%20the%20canal%20has%20a%20minimum%20bottom%20width%20of%20500%20feet%20(150%20metres)&quot; rel=&quot;nofollow noreferrer&quot;&gt;[Brittanica]&lt;/a&gt;.&lt;br /&gt;&#xA;So that would be about &lt;strong&gt;&lt;a href=&quot;https://www.wolframalpha.com/input/?i=%2843%20ft%20*8%20miles%20*%20500%20feet%29%20to%20gallons&amp;amp;wal=header&quot; rel=&quot;nofollow noreferrer&quot;&gt;7 billion gallons&lt;/a&gt; (26 billion liters)&lt;/strong&gt;.&lt;/li&gt;&#xA;&lt;li&gt;The Wikipedia articles lists Gatun Lake as 4.2 million acre*feet.&lt;br /&gt;&#xA;That's &lt;strong&gt;&lt;a href=&quot;https://www.wolframalpha.com/input/?i=%284%2C200%2C000%20acre%E2%8B%85ft%29%20to%20gallons&quot; rel=&quot;nofollow noreferrer&quot;&gt;1.4 trillion gallons&lt;/a&gt; (5.2 trillion liters)&lt;/strong&gt;.&lt;br /&gt;&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Alajuela&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Alajuela&lt;/a&gt; is another &lt;a href=&quot;https://www.wolframalpha.com/input/?i=%28600%20hm%5E3%29%20to%20gallons&quot; rel=&quot;nofollow noreferrer&quot;&gt;150 billion gallons&lt;/a&gt; (600 billion liters).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Given that the lakes are the significant amounts of water, 2 trillion gallons (8 trillion liters) would seem an extremely generous estimate for the amount of additional water impounded by the entire system (including widening the river and the water in the Gatun, Pedro Migual, and Miraflores Locks). If assumed all of that ends up being removed from the ocean, averaged over the 140 million square miles (362 million square km) of &lt;a href=&quot;https://www.google.com/search?q=surface%20area%20of%20ocean&quot; rel=&quot;nofollow noreferrer&quot;&gt;ocean surface area&lt;/a&gt;, that would be roughly &lt;strong&gt;&lt;a href=&quot;https://www.wolframalpha.com/input/?i=%282%20trillion%20gallons%20%2F%20140%20million%20square%20miles%29%20to%20micrometers&quot; rel=&quot;nofollow noreferrer&quot;&gt;20 micrometers of depth&lt;/a&gt; (less than 1/1000th of an inch)&lt;/strong&gt;, comparable to &lt;strong&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Hair%27s_breadth&quot; rel=&quot;nofollow noreferrer&quot;&gt;the width of a human hair&lt;/a&gt;&lt;/strong&gt;.  Again, remember that's a very generous estimate.&lt;/p&gt;&#xA;&lt;p&gt;Given that Wikipedia lists &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_reservoirs_by_volume&quot; rel=&quot;nofollow noreferrer&quot;&gt;48 reservoirs around the world&lt;/a&gt; that each are &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_reservoirs_by_volume&quot; rel=&quot;nofollow noreferrer&quot;&gt;more than twice the amount&lt;/a&gt; of the water estimated above, it would seem more significant to ask how much those remove in total from ocean.  Still, all those combined would seem only to be on the order of perhaps centimeters of depth lost in aggregate.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2020-11-18T04:52:00.077" LastActivityDate="2020-11-18T04:52:00.077" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20480" PostTypeId="1" AcceptedAnswerId="20505" CreationDate="2020-11-16T21:18:13.993" Score="2" ViewCount="276" Body="&lt;p&gt;I was looking into these specific minerals: arsenopyrite, pyrite, chalcopyrite, barite, calcite, dolomite. I investigate issues with tellurides not showing expected gold concentrations.&lt;/p&gt;&#xA;&lt;p&gt;There is gold predicted at the site where these samples are. We tried to prove the presence of gold through aqua regia tests, but the resulting gold concentrations are low. My suspicion is that the majority of the gold resides as an inclusion in these minerals, and the aqua regia test won't be able to show that because of its inability to dissolve the host.&lt;/p&gt;&#xA;" OwnerUserId="21374" LastEditorUserId="2470" LastEditDate="2021-08-28T10:08:14.947" LastActivityDate="2021-08-28T11:20:52.297" Title="Are there any sulphides, sulphates, carbonates that cannot be dissolved by aqua regia?" Tags="|geochemistry|mineralogy|minerals|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20481" PostTypeId="2" ParentId="20475" CreationDate="2020-11-17T09:57:38.117" Score="4" Body="&lt;p&gt;Another way to look at this is to consider that everything that was dug out was then filled by sea water. Based on this (non realistic, see below) hypothesis, we need the amount of excavated rocks as a proxy for water volume. The Panama Canal Museum &amp;quot;&lt;a href=&quot;https://cms.uflib.ufl.edu/pcm/facts.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;interesting facts&lt;/a&gt;&amp;quot; webpage has:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Excavation by French useful to present Canal (cubic yards)  29,908,000&lt;/li&gt;&#xA;&lt;li&gt;Amount of excavation by Americans in cubic yards 232,353,000&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Yielding a total of 262 261 000 cubic yards, or &lt;span class=&quot;math-container&quot;&gt;$\sim$&lt;/span&gt;0.2 km&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt; of excavated material. Now if you take this volume of water from the 362 million square kilometers area of the World Ocean, you get a depth of:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\frac{0.2}{362000000} = 5.5 \times 10^{-10}$&lt;/span&gt; km, or 0.55 microns.&lt;/p&gt;&#xA;&lt;p&gt;However, the premise is false because most of the canal is filled with fresh water, not sea water. The Gatún Lake mentioned in @JeopardyTempest's answer is fed by a river.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-11-17T09:57:38.117" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20482" PostTypeId="2" ParentId="8222" CreationDate="2020-11-17T21:11:42.367" Score="4" Body="&lt;p&gt;While it is true that, at least over time, Earth will equilibrate so the mountain sinks down, displacing the denser material below, this would also mean that the material just beside the mountain is less dense, and thus there is a similar reduction in g due to this when standing beside it.&lt;/p&gt;&#xA;&lt;p&gt;And while the increased mass is quite small relative to Earth, you are also a lot closer to it. So you need to consider both factors.&lt;/p&gt;&#xA;&lt;p&gt;If we do a first order approximation for the change in gravity due to the height of the mountain, we get;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;dg=\frac{2 G M h}{R^3}&#xA;$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; is the radius of Earth, &lt;span class=&quot;math-container&quot;&gt;$M$&lt;/span&gt; is the mass of Earth and &lt;span class=&quot;math-container&quot;&gt;$h$&lt;/span&gt; is the height of the mountain.&lt;/p&gt;&#xA;&lt;p&gt;If we treat the mountain as a sphere with a diameter of &lt;span class=&quot;math-container&quot;&gt;$h$&lt;/span&gt; and a density of &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt;, then the acceleration due to gravity when standing on top of it is:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;a=\frac{G \rho (4/3) \pi (h/2)^3}{(h/2)^2}&#xA;=\frac{2 G \pi \rho h}{3}&#xA;$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;And with that we end up with a ratio of the 2 forces dependent upon the density of the mountain (as both are linearly dependent upon the height)&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\frac{a}{dg}=\frac{\pi \rho R^3}{3M}&#xA;$$&lt;/span&gt;&#xA;So for a spherical mountain you need a density of roughly 22000 kg/m^3, e.g. a mountain of osmium, to have the gravity due to the mountain increase your weight more than the extra height decreases it.&lt;/p&gt;&#xA;&lt;p&gt;Having mass in addition to that sphere (without taking away from that sphere) would reduce that density requirement.&#xA;But even if you modelled it as a cylinder where h=d to calculate the mass, and overestimated the force due to gravity by treating it as a sphere/point mass, you end up needing a density of roughly 15000 kg/m^3.&lt;/p&gt;&#xA;&lt;p&gt;However the effect is much greater than the 0.2% suggested by userLTK. With a specific gravity of 2.7, the effect of the mass of the spherical mountain is 12% that of the effect of the increased distance from Earth.&lt;/p&gt;&#xA;" OwnerUserId="21381" LastActivityDate="2020-11-17T21:11:42.367" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20483" PostTypeId="1" AcceptedAnswerId="20766" CreationDate="2020-11-17T23:26:10.763" Score="4" ViewCount="174" Body="&lt;p&gt;What amount of average sea level rise (in meters above 2020 levels) would be associated with a 25% increase in total ocean volume?&lt;/p&gt;&#xA;&lt;p&gt;The reason I ask is because of &lt;a href=&quot;https://sciencenordic.com/chemistry-climate-denmark/the-earth-has-lost-a-quarter-of-its-water/1462713&quot; rel=&quot;noreferrer&quot;&gt;this study&lt;/a&gt; that indicates Earth has lost appx. 25% of its water to space via methanogenesis process splitting the hydrogen molecules off of H2O, then the hydrogen escaping into space.&lt;/p&gt;&#xA;&lt;p&gt;Regardless of whether this study is accurate, it has made me wonder what the Earth would have looked like with 25% more water. How much of a sea-level rise would that represent?&lt;/p&gt;&#xA;&lt;p&gt;Obviously this would be a fairly complex equation since terrain is not uniform in contour. Less land is displacing every new layer of water you ade, compared to a lower layer of water. So (in addition to any changes from the radius of the sphere increasing) there should be a decreasing amount of average sea level increase per unit of water volume, until all land is covered.&lt;/p&gt;&#xA;&lt;p&gt;I've looked to &lt;a href=&quot;https://www.floodmap.net/&quot; rel=&quot;noreferrer&quot;&gt;FloodMap.net&lt;/a&gt; for an answer, but they don't seem to provide the amount of water volume, at least, not to free users.&lt;/p&gt;&#xA;&lt;p&gt;Curious if there is an open source code library that can handle this kind of calculation, or if there is a simple formula that would get us within a reasonable margin of error (i.e. it would provide a sea level that could be plugged into FloodMap to show what shorelines would look like under 25% more water, given today's continents).&lt;/p&gt;&#xA;" OwnerUserId="21382" LastActivityDate="2021-02-07T04:10:19.950" Title="How far would average sea level rise from a 25% increase in total ocean volume?" Tags="|climate-change|oceanography|earth-history|sea-level|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20484" PostTypeId="1" CreationDate="2020-11-18T02:57:32.983" Score="3" ViewCount="129" Body="&lt;p&gt;The Washington Post article &lt;a href=&quot;https://www.washingtonpost.com/weather/2020/11/17/greek-letter-hurricane-names-retire/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hurricanes Eta and Iota brought disaster to Central America. Officials can’t retire their names.&lt;/a&gt; describes a complicated situation, aspects of which are:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Eta roared ashore in northern Nicaragua on Nov. 3, followed by Iota exactly 13 days later and just 15 miles to the south. Both were Category 4 hurricanes at landfall, though Iota had attained Category 5 status offshore. The pair brought flood disasters across Central America, in addition to extreme wind and storm surge near the coast.&lt;/p&gt;&#xA;&lt;p&gt;They’re the textbook candidates for having their names axed from the Hurricane Center’s six-year rotating name list. Just as Katrina was replaced by Katia, Michael with Milton, and Sandy with Sara, there would ordinarily be little question that the name of a deadly and destructive Category 4 hurricane would be retired. But in the case of the Greek alphabet, there’s no easy replacement.&lt;/p&gt;&#xA;&lt;p&gt;“The Committee … agreed that it was not practical to ‘retire into hurricane history’ a letter in the Greek Alphabet,” read a news release from the World Meteorological Organization, which oversees hurricane naming across the world’s oceans.&lt;/p&gt;&#xA;&lt;p&gt;Instead of removing a letter from the list, Greek letters can only be symbolically retired. Under the current policy, “Eta 2020” and “Iota 2020” would be listed as retired storms if the WMO voted accordingly, but the names Eta and Iota would remain in circulation for future storms. &lt;strong&gt;Some meteorologists fear this defeats the purpose of retiring names, while others find that assigning Greek letters to storms is impractical to begin with.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Why exactly were Greek letters used as names for Hurricanes in the first place, despite the fairly obvious and predictable impracticalities? Certainly this exact problem was brought up, how was it dismissed?&lt;/p&gt;&#xA;&lt;p&gt;Related but different (because the current question is backward-looking), and also in need of answers:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/20222/6031&quot;&gt;In the future, is the World Meteorological Organization going to allow Hurricanes Zeta, Eta, and Theta to exist simultaneously?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/20224/6031&quot;&gt;What will happen if the Greek letter names were exhausted for naming tropical storms?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2020-11-18T21:16:15.353" Title="Why exactly did the use of Greek letters as names for Hurricanes happen the first place, despite the fairly obvious and predictable impracticalities?" Tags="|meteorology|tropical-cyclone|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="20485" PostTypeId="1" CreationDate="2020-11-18T08:02:10.880" Score="4" ViewCount="131" Body="&lt;p&gt;It is known that the earth has a magnetic field and gravitational field around it, I wish to ask to what degree is the chemistry on the planet is influenced by these fields? How would the chemical reactions seen everyday on earth be different if the strengths of these fields were different?&lt;/p&gt;&#xA;" OwnerDisplayName="user21385" LastActivityDate="2020-12-18T13:37:52.043" Title="How much does the gravitational and magnetic fields of a planet effect the chemistry in it?" Tags="|geochemistry|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20487" PostTypeId="1" AcceptedAnswerId="20488" CreationDate="2020-11-17T23:57:33.353" Score="1" ViewCount="71" Body="&lt;p&gt;&lt;a href=&quot;https://9gag.com/gag/aBme0M2&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://9gag.com/gag/aBme0M2&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This one says it is&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oHwBE.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oHwBE.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I am not sure whether to ask this in geology or biology.&lt;/p&gt;&#xA;&lt;p&gt;How does marine fossils show up in mountains?&lt;/p&gt;&#xA;" OwnerDisplayName="user4951" LastEditorUserId="18081" LastEditDate="2020-11-18T13:04:28.300" LastActivityDate="2020-11-18T18:30:38.107" Title="Are marine fossils in the mountain happens due to lower sea levels?" Tags="|sea-level|mountains|fossils|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20488" PostTypeId="2" ParentId="20487" CreationDate="2020-11-18T00:19:14.687" Score="1" Body="&lt;p&gt;&lt;strong&gt;Update&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Note that this answer was given when this question was on biology.stackexchange.com. @jamesqf has IMO a better, more informed, more helpful answer below. I don't pretend to know much of anything about geology!&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Original answer&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I'd say that Geology is the better venue, but nonetheless here is an answer.&lt;/p&gt;&#xA;&lt;p&gt;Note that there are lots of reasons why elevation changes in geology. The structure of the Earth's crust is itself constantly in motion, such that new plateaus and mountains can be &amp;quot;born&amp;quot; from the sea's floor and thrown up by volcanism, temperature changes, plate friction, etc.&lt;/p&gt;&#xA;&lt;p&gt;This seems to be pretty old work in geology, see e.g. &lt;a href=&quot;https://science.sciencemag.org/content/os-2/46/206.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="21386" OwnerDisplayName="Maximilian Press" LastEditorUserId="21386" LastEditDate="2020-11-18T18:30:38.107" LastActivityDate="2020-11-18T18:30:38.107" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20489" PostTypeId="2" ParentId="20487" CreationDate="2020-11-18T02:48:57.093" Score="6" Body="&lt;p&gt;Leonardo was wrong about this.  It is not due to sea level dropping (except in very isolated cases), it's due to the land rising.  Sedimentary rocks that form in sea beds are often uplifted by tectonic processes to form mountains and plateaus.  See e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Sedimentary_rock&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Sedimentary_rock&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1401" OwnerDisplayName="jamesqf" LastActivityDate="2020-11-18T02:48:57.093" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20490" PostTypeId="2" ParentId="20484" CreationDate="2020-11-18T21:16:15.353" Score="5" Body="&lt;p&gt;Well for one major reason, the assumption was that seasons with so numerous hurricanes were rare. Canonically, tropical cyclones typically follow a &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/JZ065i001p00213&quot; rel=&quot;noreferrer&quot;&gt;Poisson Distribution&lt;/a&gt;. If you consider that, of the English alphabet, only 21 of 26 letters are used for names, and if you assume that the average number of hurricanes from the past decade were to stay unchanged compared to this decade &lt;a href=&quot;https://en.wikipedia.org/wiki/Atlantic_hurricane_season#2010s&quot; rel=&quot;noreferrer&quot;&gt;(155 tropical storms/10 years= 15.5 tropical storms per year)&lt;/a&gt;, then the probability of going over 21 tropical cyclones is about 6.96%. &lt;a href=&quot;https://public.wmo.int/en/media/news/2020-hurricane-season-exhausts-regular-list-of-names&quot; rel=&quot;noreferrer&quot;&gt;Such a view is backed up by the World Meteorological Organization&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;But if you say, &amp;quot;aren't the number of tropical cyclones supposed to increase under climate change?&amp;quot; to challenge my assumption of constant tropical cyclones per decade, I will argue that canonically, &lt;a href=&quot;https://www.noaa.gov/news/study-climate-change-has-been-influencing-where-tropical-cyclones-rage&quot; rel=&quot;noreferrer&quot;&gt;the frequency that tropical cyclones form should decrease, but the intensity should increase&lt;/a&gt;. So the assumption doesn't actually hold, but should actually overestimate the probability of more hurricanes in the long term.&lt;/p&gt;&#xA;&lt;p&gt;So why use Greek letters? Well, to be consistent, something has to be used to draw attention to the storm. Cycling back to the A's sends the wrong message. And &lt;a href=&quot;https://www.fox23.com/news/science/2020-hurricane-season-could-use-greek-alphabet-only-second-time-ever/2K2GBUHGDRD2ZG5HEFW4P37DRM/&quot; rel=&quot;noreferrer&quot;&gt;the Greek alphabet was used previously, without major consequence&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Arguably, it may be easier to only name storms that make hurricane strength. However, that would be inconsistent, and may miss strong, rain-heavy storms. For example, &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_Storm_Allison&quot; rel=&quot;noreferrer&quot;&gt;Tropical Storm Allison was retired without making the hurricane wind requirement&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-11-18T21:16:15.353" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20491" PostTypeId="1" CreationDate="2020-11-18T22:26:15.357" Score="3" ViewCount="68" Body="&lt;p&gt;I recently came across &lt;a href=&quot;https://cleantechnica.com/2020/11/15/oil-and-gas-drilling-technology-district-heating-feasible/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; outlining the use of our advancements in oil and gas drilling to implement &amp;quot;district heating&amp;quot; (or geothermal heating for our buildings/cities as a whole) by pumping water underground to be heated by the mantle, then pumped back up to the surface. I like the premise and it sounds great, but what are the effects? This seems like alcohol expanding our capillaries, we feel warmer but as a whole are getting colder as heat is lost more rapidly on the surface.&lt;/p&gt;&#xA;&lt;p&gt;If accomplished globally would there be a significant decrease in the temperature of the mantle?&lt;/p&gt;&#xA;&lt;p&gt;Would areas of high use cool the mantle there, forcing a deeper crust at those locations? Or is the amount of energy used so minuscule in comparison there'd be no discernible difference? What about after a millennia of use?&lt;/p&gt;&#xA;&lt;p&gt;Hopefully helpful diagram for reference? Maybe redundant in this SE, I just joined so lmk&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OMDYf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OMDYf.png&quot; alt=&quot;crust-mantle-core-diagram&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(&lt;a href=&quot;https://handygeography.wordpress.com/gcse/the-restless-earth-revision-materials/structure-of-the-earth/&quot; rel=&quot;nofollow noreferrer&quot;&gt;image credit&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;I know I asked a few questions, but those all stem from the title &amp;quot;How would district heating affect the temperature of the earth's mantle/core?&amp;quot;&lt;/p&gt;&#xA;" OwnerUserId="21388" LastActivityDate="2020-11-18T22:26:15.357" Title="How would district heating affect the temperature of the earth's mantle/core?" Tags="|geothermal-heat|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20493" PostTypeId="2" ParentId="14267" CreationDate="2020-11-19T15:40:12.260" Score="3" Body="&lt;p&gt;Annum and year are not the exact same thing. The exact length of a year depends on what exactly you are measuring, whether distance between perihelions, distance between solstices, etc. It also varies because of the gravitation of other planets. These effects are minor, but enough that measuring units of years is tricky. So an annum is defined as 31,557,600 seconds exactly.&lt;/p&gt;&#xA;" OwnerUserId="21390" LastActivityDate="2020-11-19T15:40:12.260" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20494" PostTypeId="1" CreationDate="2020-11-19T16:58:11.560" Score="1" ViewCount="29" Body="&lt;p&gt;I am trying to estimate wood volume for forest stands I have field-inventoried using a variable plot sample method, measuring species, DBH, and height of each tree counted 'in' using a BAF-10 prism. In my area, International-1/4 log rule is used to estimate volumes. I found &lt;a href=&quot;http://www.uky.edu/%7Ejmlhot2/bdft_tables/table_5.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;a table for that&lt;/a&gt; in general but not specific to species. In any case, it also seems very tedious to lookup each volume based on DBH &amp;amp; height I recorded, since there are about 220 measures trees over 21 plots for a ~50 acre forest.&lt;/p&gt;&#xA;&lt;p&gt;How do professionals efficiently apply DBH and height to estimate volumes? I imagine there is a digital lookup table of volumes, ideally per species, and there is a way to programmatically (in a spreadsheet) lookup the volume based on row corresponding with DBH and column corresponding with height. I have not been able to find digital lookup tables for species however (only PDF or paper ones), or a method for that kind of row-col lookup in Excel.&lt;/p&gt;&#xA;&lt;p&gt;I am in NY, USA, with majority species being eastern hemlock, red maple, yellow birch, black cherry, red spruce, and balsam fir.&lt;/p&gt;&#xA;" OwnerUserId="4789" LastActivityDate="2020-11-19T16:58:11.560" Title="How to efficiently estimate merchentable volume for timber inventory using species, DBH, and merchentable heights?" Tags="|measurements|agriculture|data-analysis|forest|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20496" PostTypeId="2" ParentId="20406" CreationDate="2020-11-20T00:49:54.823" Score="0" Body="&lt;p&gt;Silica is Silicon dioxide, Sand being it's most abundant availability source. &amp;quot;Fossil Sand&amp;quot; contains various other rocks and crushed fossils, etc.&#xA;The Two most abundant rocks on earth, Granite and Basalt.&#xA;But quartz is it's most abundant source with an overall purity of 90+ percent.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-11-20T00:49:54.823" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20498" PostTypeId="1" CreationDate="2020-11-20T06:56:55.187" Score="5" ViewCount="729" Body="&lt;p&gt;I recently read a &lt;a href=&quot;https://fanf.dreamwidth.org/133823.html?fbclid=IwAR1O5awjNok30m30PjbuoHuqhDIYTx1z2xcgHEDfzsKKZ85bTZuS1iNuTpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;blog entry&lt;/a&gt; from a leap-second expert explaining that in near term (i.e. last 3 years) the Earth has been spinning ever so slightly faster, delaying the need to insert a leap-second (that accounts for the Earth spinning at a different speed than once per 24 * 60 * 60 seconds).&lt;/p&gt;&#xA;&lt;p&gt;That got me wondering what effect Climate Change might have had on the spin of the Earth over the last century, and into the next.&lt;/p&gt;&#xA;&lt;p&gt;I reasoned that melting ice caps would bring mass closer to the centre, lowering the moment of inertia and speeding up the spin (which was a silly thought - see comments).&lt;/p&gt;&#xA;&lt;p&gt;But then I reasoned that warming oceans would lower the density of water, pushing the mass away.&lt;/p&gt;&#xA;&lt;p&gt;Then I realised I had no idea what effect of the changing atmosphere might have.&lt;/p&gt;&#xA;&lt;p&gt;I came away knowing I had a very poor understanding of the problem.&lt;/p&gt;&#xA;&lt;p&gt;What predictions do the scientific models make about the effect of climate change on the previous rate of gradual slowing of the Earth's spin?&lt;/p&gt;&#xA;&lt;p&gt;[Note: This is an idle curiosity question from a non-expert. Please tailor your answering efforts appropriately.]&lt;/p&gt;&#xA;" OwnerUserId="2976" LastEditorUserId="2976" LastEditDate="2020-11-20T19:45:58.513" LastActivityDate="2021-01-11T23:10:38.467" Title="What effect does climate change have on the Earth's rotation?" Tags="|climate-change|planetary-science|earth-rotation|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="20499" PostTypeId="1" AcceptedAnswerId="20670" CreationDate="2020-11-21T08:32:08.243" Score="1" ViewCount="50" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;In the Himalayan-Tibetan plateau, both normal and thrust faults are observed. Geological&#xA;age dating suggests thrust faults are older (before 18-20 Ma) than the normal faults (after 18-20&#xA;Ma). &lt;strong&gt;Explain this observation.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Why is this the case? I'm unable to explain this using whatever I have learned so far. I am a beginner in the field of Earth Sciences, and I would appreciate a detailed answer (or any helpful pointers) so I can better understand these concepts!&lt;/p&gt;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;&lt;p&gt;P.S. I'm also new to this website, so pardon me if my question isn't in line with any of the guidelines. Let me know how I can improve it.&lt;/p&gt;&#xA;" OwnerUserId="21396" LastActivityDate="2021-01-11T12:08:15.550" Title="Why are thrust faults older than normal faults in the Himalayan-Tibetan plateau?" Tags="|dating|tibetan-plateau|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20500" PostTypeId="2" ParentId="20485" CreationDate="2020-11-21T11:38:46.437" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;How would the chemical reactions seen everyday on earth be different if the strengths of these fields were different?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Depends. If you're just talking about higher &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; (i.e &lt;span class=&quot;math-container&quot;&gt;$g&amp;gt;9.8\ \rm{m/s}^2$&lt;/span&gt;) but the same atmospheric pressure, than not much will change &lt;em&gt;on&lt;/em&gt; the surface of the earth.&lt;/p&gt;&#xA;&lt;p&gt;If the atmospheric pressure changes, there could be changes to chemical reactions. There are several factors controlling chemical reactions. One being, obviously, the identity of the reactants. The other one is temperature. But also important is pressure. Because pressure on the surface of the earth is always 1 atm, no one really thinks or cares about pressure. No one, until it changes. That said, for any substantial change in chemistry, pressure has to change quite a lot, which would make earth uninhabitable for humans, so there would be no one to see that chemistry changed.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-11-21T11:38:46.437" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20501" PostTypeId="1" CreationDate="2020-11-21T12:23:19.373" Score="4" ViewCount="56" Body="&lt;p&gt;I am a student in industrial engineering, and I am doing a business plan related to exploiting Messina Strait current for electrical energy.&#xA;Does anyone have a tidal stream chart (either with velocity or energy), that I could use? Thank you to everyone&lt;/p&gt;&#xA;" OwnerUserId="13846" LastActivityDate="2020-11-21T12:23:19.373" Title="Tidal current energy chart - Messina Strait" Tags="|waves|mediterranean|energy|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20502" PostTypeId="1" AcceptedAnswerId="20510" CreationDate="2020-11-21T13:18:55.257" Score="6" ViewCount="189" Body="&lt;p&gt;I am interested in getting a better overview of the full history of the Earth and the evolution of life. Therefore I am looking for a book that goes through the different geological time scales of the Earth and discusses major changes that took place. I am not an Earth scientist or a biologist, so I don't want it to be too formal. However, I do like it to be quite informative and with rich illustrations if possible.&lt;/p&gt;&#xA;&lt;p&gt;Does anyone have any recommendations on good titles?&lt;/p&gt;&#xA;" OwnerUserId="21372" LastEditorUserId="18081" LastEditDate="2022-08-04T09:08:25.057" LastActivityDate="2022-08-04T09:08:25.057" Title="Book on the history of Earth and life on Earth" Tags="|earth-history|paleontology|reference-request|evolution|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20504" PostTypeId="1" AcceptedAnswerId="20509" CreationDate="2020-11-22T12:41:45.733" Score="1" ViewCount="93" Body="&lt;p&gt;As a beginner for &lt;strong&gt;CFD modelling of plate subduction&lt;/strong&gt;, I heard comsol to be a good software. Can anybody suggests alternatives and the demerits of using &lt;em&gt;COMSOL Multiphysics&lt;/em&gt;? Thank you.&lt;/p&gt;&#xA;" OwnerUserId="21399" LastEditorUserId="18081" LastEditDate="2020-11-23T09:57:36.190" LastActivityDate="2020-11-23T21:29:27.363" Title="Is COMSOL Multiphysics good for subduction CFD modelling? Are there alternatives?" Tags="|geophysics|plate-tectonics|models|fluid-dynamics|subduction|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20505" PostTypeId="2" ParentId="20480" CreationDate="2020-11-22T15:43:21.900" Score="3" Body="&lt;p&gt;This was also asked in Chemistry Stack Exchange, where it was noted that barium sulfate is insoluble in water and generally insoluble in acids.  A quick check reveals that indeed the other minerals can be dissolved in nitric acid and so should yield to aqua regia.  Thus barite is the troublemaker.&lt;/p&gt;&#xA;&lt;p&gt;Barite can be dissolved in hot alkaline chelating solutions, as described &lt;a href=&quot;https://jpst.ripi.ir/article_707.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here[1]&lt;/a&gt;.  This, of course, is not compatible with the acidic solvent you intend to use to dissolve and measure the gold.  It is not clear from the reference whether a pretreatment with such a chelating agent to remove the barite before placing in aqua regia would work when the barite is intermixed with the alkali-insoluble sulfides listed in the question.&lt;/p&gt;&#xA;&lt;p&gt;Reference&lt;/p&gt;&#xA;&lt;p&gt;1.&#xA;Bader Salem Ba Geri, Mohamed A. Mahmoud, Reyad A. Shawabkeh,  Abdulazeez Abdulraheem, &amp;quot;Evaluation of Barium Sulfate (Barite) Solubility Using Different Chelating Agents at a High Temperature&amp;quot;, &lt;em&gt;Journal of Petroleum Science and Technology&lt;/em&gt; &lt;strong&gt;7&lt;/strong&gt;(2017), 1, 42-56.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2021-08-28T11:20:52.297" LastActivityDate="2021-08-28T11:20:52.297" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20507" PostTypeId="1" CreationDate="2020-11-23T14:17:38.013" Score="3" ViewCount="39" Body="&lt;p&gt;Now I am working on a Tropical Cyclone project, and want to figure out the SST status when a TC passes by. I've been searching for SST products, yet there only show up to daily SST. My question is does there exist four-times daily SST, and if no, why is that?&lt;/p&gt;&#xA;" OwnerUserId="14147" LastActivityDate="2020-11-23T17:38:58.200" Title="Are there four-times daily sea surface temperature (SST) data product for Tropical Cyclone research?" Tags="|oceanography|tropical-cyclone|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20508" PostTypeId="2" ParentId="20507" CreationDate="2020-11-23T17:38:58.200" Score="1" Body="&lt;p&gt;The issue with satellite &lt;a href=&quot;http://www2.hawaii.edu/%7Ejmaurer/sst&quot; rel=&quot;nofollow noreferrer&quot;&gt;SST&lt;/a&gt; is that in most cases it is captured via infrared radiometers. Those sensors can't see through clouds. Daily products are used to try to remove the cloud effects. Alternatively, passive microwave radiation can be used (e.g., TMI, AMSR2, AMSR-E). &lt;a href=&quot;http://remss.com/measurements/sea-surface-temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;It is not affected by cloud cover, but has lower horizontal resolution&lt;/a&gt; (~25km, vs 1-5km from IR).  You can try to get the individual passes of each satellite and deal with gaps: &lt;a href=&quot;https://images.remss.com/amsr/amsr2_data_daily.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;For instance&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2020-11-23T17:38:58.200" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20509" PostTypeId="2" ParentId="20504" CreationDate="2020-11-23T21:29:27.363" Score="2" Body="&lt;p&gt;numerical modelling is a vast field and the tool to address your problem depends strongly on ... your problem and your approach!&lt;/p&gt;&#xA;&lt;p&gt;Are you a master student? a PhD student with very short time to wrap up your thesis? A plumber with an intelectual interest in plate tectonics?&lt;/p&gt;&#xA;&lt;p&gt;In short: Comsol may be an adequate tool. However, with large displacements (larger than the element volumes), you may want to avoid Finite Element method and probably better to have a look at other methods.&#xA;You can find a nice description of alternative methods in the book &amp;quot;Introduction to Numerical Geodynamic Modelling&amp;quot; from Professor Taras Gerya. He sugests to use Matlab, but you can probably follow all the book simply with Python.&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2020-11-23T21:29:27.363" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20510" PostTypeId="2" ParentId="20502" CreationDate="2020-11-24T04:48:33.210" Score="7" Body="&lt;h2&gt;Cowen's History of Life&lt;/h2&gt;&#xA;&lt;p&gt;Your best bet is  &lt;em&gt;Cowen's History of Life&lt;/em&gt;, it is an excellent introductory textbooks for paleontology well laid out and clearly written with introductory students in mind so a laymen will be fine. It covers the entire breadth of the life. Check the edition though there are six of them now and the older ones are pretty outdated and not laid out as well. if it wasn't so expensive I would buy it to give to people.&lt;/p&gt;&#xA;&lt;p&gt;I can recommend a few more specialized texts, to dig deeper [pun intended]&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Terrestrial Ecosystems Through Time: Evolutionary Paleoecology of Terrestrial Plants and Animals&lt;/em&gt; which is an excellent review of terrestiral life.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Invertebrate Palaeontology &amp;amp; Evolution&lt;/em&gt;&#xA;by Clarkson which is a beautiful textbook yet still accessible to the laymen since it is written for undergraduates.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Introduction to Paleobiology and the Fossil Record&lt;/em&gt; by Benton and Harper is the best introduction to paleontology in general you can get, and may be worth a look if you are having trouble with the other books make.&lt;/p&gt;&#xA;&lt;p&gt;A lot of searches will point you to &lt;em&gt;Life: A Natural History of the First Four Billion Years of Life on Earth&lt;/em&gt; It is OK but the author very much has their storytelling hat on. Great for making it a more enjoyable read, bad if you want information. It reads more like a biography.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2020-11-24T04:48:33.210" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20511" PostTypeId="1" CreationDate="2020-11-25T17:06:14.540" Score="1" ViewCount="17" Body="&lt;p&gt;I'm wanting to know where/if I can find 2019 records of hourly rainfall  in New Zealand particularly for November in Greymouth South Island&lt;/p&gt;&#xA;" OwnerUserId="21414" LastActivityDate="2020-11-25T17:06:14.540" Title="Historical detailed rainfall recordings New Zealand" Tags="|meteorology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20512" PostTypeId="1" CreationDate="2020-11-25T17:51:09.857" Score="2" ViewCount="105" Body="&lt;p&gt;I want to do a project with very high resolution temperature data from a city (any city) with very high resolution (&amp;lt;10 m), in an attempt to create an animated 3D microclimate map for that city.&lt;/p&gt;&#xA;&lt;p&gt;The data would probably have to be raster data and it should be a time series of any kind (could be hourly but could also daily, the goal here is to test the 3D animated presentation). Where could I get such data?&lt;/p&gt;&#xA;" OwnerUserId="14690" LastActivityDate="2020-12-31T18:08:20.870" Title="Where do I get hourly temperature data for cities with a high resolution?" Tags="|temperature|open-data|urban-climate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20513" PostTypeId="1" CreationDate="2020-11-27T10:50:05.440" Score="1" ViewCount="128" Body="&lt;p&gt;There are empty lowlands in Australia and Iran like Dasht-e Lut. If we fill these lands with ocean water then could we reduce the global sea level and save coastal cities like venice?&lt;/p&gt;&#xA;" OwnerUserId="21425" LastActivityDate="2021-02-12T03:09:13.210" Title="It is possible to reduce global sea level via filling empty lowlands with ocean water?" Tags="|climate-change|sea-level|" AnswerCount="1" CommentCount="7" ClosedDate="2021-02-13T09:45:25.310" ContentLicense="CC BY-SA 4.0" />
  <row Id="20514" PostTypeId="1" CreationDate="2020-11-27T13:20:26.357" Score="1" ViewCount="44" Body="&lt;p&gt;Weather providers, such as GFS and ECMWF usually provide their data in 3-6 hour intervals.&lt;/p&gt;&#xA;&lt;p&gt;What would be the best method to interpolate between the intervals to get a good intermediate wind model?&lt;/p&gt;&#xA;&lt;p&gt;I found &lt;a href=&quot;https://esrl.noaa.gov/gsd/eds/gfesuite/pubs/Interpolating-Between-Grids-of-Meteorological-Data-for-AFPS.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt; - it suggests interpolating speed and wind direction separately, but this still seems a bit simplistic to me...&lt;/p&gt;&#xA;" OwnerUserId="21426" LastActivityDate="2020-11-27T13:20:26.357" Title="What are the leading methods for temporally interpolating wind data?" Tags="|meteorology|weather-forecasting|extreme-weather|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20515" PostTypeId="2" ParentId="7136" CreationDate="2020-11-27T17:22:13.790" Score="1" Body="&lt;p&gt;It can't be done. That is my guess. I think you would need a pressure suit or cabin.&lt;/p&gt;&#xA;&lt;p&gt;I am a former USAF weather officer with flight experience. I have a Masters Degree in Meteorology and a BS in Space Physics. I have working experience in analyzing the jet stream and also using data for vertical airspeed (or omega, as some call it). That does not give me magic powers or even make me generally correct at any time, but I think it provides me with a rough familiarity to review the question and mention the key issues it raises. I ask for your trust in my meteorology and flight experience when I say that you should not assume you have good reason to trust in your idea just because some of the answers got a lot of thumbs up or seem like they good answers. Based on my training and experience, none of the answers that predate mine have justified your idea. The point of that is to keep you skeptical, not to conduct ad hominem attacks to support my own answer. I don't care if I get one up vote.&lt;/p&gt;&#xA;&lt;p&gt;I think with a pressurized suit of some sort and a massive soaring aircraft, some day a circumnavigation will be completed. It's almost inevitable, but how and when is the question.&lt;/p&gt;&#xA;&lt;p&gt;I think your idea won't work unless you use dynamic soaring. Period. You seem to be under the impression a trip might succeed using the vertical velocity of the atmosphere for lift. However, across broad areas where lift would be needed, the atmosphere would rise at only a few cm/s. For scale analysis, let's pick a number and say 3 cm/s. As the air would be rising and bringing your craft with it, your kite would only maintain altitude with a descent rate not exceeding 3 cm/s.  (In reality, due to other issues, probably MUCH less than 3 cm/s would be required!). How achievable is a 3 cm/s descent rate? Well, let's look at a glide slope ratio analysis and compare the result to existing soaring aircraft.&lt;/p&gt;&#xA;&lt;p&gt;Slope Analysis:&#xA;If your kite is extremely efficient, you will probably not have a very fast forward air speed. After all, the aircraft's drag goes up with the square of velocity (assuming constant drag coefficient) so you would probably travel with low air speed. Let's say you are traveling forward at just 60 knots, which is close to 30 m/s. That is also 3000 cm/s forward air speed. If you had a descent rate of 3 cm/s, your ratio of forward speed to vertical speed would be 3000 cm/s to 3 cm/s, or 1000:1. How does that glide ratio compare to world-class sailplanes?  Well, an extremely efficient open-class glider might have a glide ratio of 70:1, so your design would have to get FOURTEEN times more distance out of the glide slope of the best aircraft. Put another way, you are trying to be FOURTEEN TIMES MORE EFFICIENT at utilizing energy. That may be possible, but you are talking about a massive change in design technology.&lt;/p&gt;&#xA;&lt;p&gt;All of this scale analysis assumes you are always in an area of robust uplift. Unfortunately, the atmosphere is not like that, not even on the south side of &amp;quot;THE&amp;quot; jet stream. In fact, where the jet stream speeds up, those sections are called &amp;quot;jet streaks&amp;quot; and they have descending air in two of the four quadrants that surround them (and likewise for jet sinks). So, it's not some easy picture as a simplified schematic suggests. Your aircraft would constantly go through places of descending air as well. So, it seems to me that your aircraft would need tens of times better glide slope than an efficient glider. That's not a very easy path to success.&lt;/p&gt;&#xA;&lt;p&gt;Instead of using rising air, I think you would need to copy the technique of countless seabirds who use dynamic soaring. They are able to travel much farther and more quickly than birds that only depend on updrafts. It's a simple analysis, but nature seems to be pointing the way!&lt;/p&gt;&#xA;&lt;p&gt;Dynamic soaring around the globe would require a nearly continuous trail of highly differential shear. Where the continuity is broken, you would be losing altitude until you found another location of differential shear. Above the tropopause, perhaps that is possible with a sufficiently advanced aircraft. I doubt it is possible below the tropopause, where areas of no lift and occasional turbulence would both be enemies of your kite. So, I leave a scale analysis for dynamic soaring possibilities to someone else. I suspect it would be a more likely path to success, but still it would require massive improvement in soaring efficiency as well as highly detailed knowledge of where the differential shear is located.&lt;/p&gt;&#xA;&lt;p&gt;Also, I think you would definitely need pressurization or else you would need a lot of specialized breathing training and still take on a lot of risk to your life and limb.&#xA;Without cabin or full suit pressurization, you would need to breathe pressurized oxygen, which means forcibly breathing out against HIGH positive pressure on EVERY breath for days on end. Your mask would be crushed against your face. Goodness knows how your eyeballs and other body parts would eventually react. I have done some of the positive pressure breathing in a USAF pressure chamber (Peterson AFB). It didn't seem sustainable. I have seen videos of this positive pressure breathing in actual aircrew exercises. It looks quite challenging! And that is only at altitudes that might not be high enough for your kite idea to succeed.&lt;/p&gt;&#xA;&lt;p&gt;Breathing out against this pressure for long periods of time causes health problems and is exhausting. I even wonder if such a long period of positive-pressure breathing could kill you through embolism or some other form of respiratory-related injury. Even with sufficiemt positive pressure to drive up the partial pressure of oxygen in your blood, if you got too far above the tropopause, no amount of positive pressure would even keep you alive. So, your flight would be limited to areas below 40,000 feet, which means you could not circumnavigate close to the equator where the tropopause exceeds that altitude.&lt;/p&gt;&#xA;&lt;p&gt;As for your general understanding of a physical path to gliding 'round the globe, &amp;quot;THE&amp;quot; jet stream is ALWAYS just a term for RELATIVE velocity distribution. What looks like a continuous jet stream around the world might be a stream with 300 knots over Alaska but then only 60 knots over the Atlantic! That's why looking at numbers and not just colors and lines is important. Likewise, the horizontal and vertical gradients of the &amp;quot;horizontal&amp;quot; velocity would vary widely, as would vertical velocity. I can definitively say that in all my of days doing manual analysis of the jet stream (before computers were left to do it alone), I found it unusual to find a continuous jet across the Western Northern hemisphere, let alone fully around the globe in either the Northern OR Southern Hemisphere. Now imagine looking for a jet stream AND significant differential shear along the jet. It would be quite an endeavor. It may be possible, but the idea would require in-depth study of the wind patterns, not just for theoretical feasibility but likelihood it would be feasible to find necessary and sustained conditions on the special day an aircraft would be ready for launch.&lt;/p&gt;&#xA;&lt;p&gt;The idea of circumnavigation by natural power alone is an old one. However, there is always room for more achievement. I think someday someone might circumnavigate the globe in a special gliding craft, but I do think they will use a pressure suit or cabin.&lt;/p&gt;&#xA;" OwnerUserId="7800" LastEditorUserId="7800" LastEditDate="2021-10-25T16:50:16.630" LastActivityDate="2021-10-25T16:50:16.630" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20516" PostTypeId="2" ParentId="14915" CreationDate="2020-11-27T17:41:24.480" Score="2" Body="&lt;p&gt;It seems your question was more like a thinking exercise rather than a question.&lt;/p&gt;&#xA;&lt;p&gt;I cannot answer your question with robust confidence in the current state of knowledge. The fact is, I have always shared your skepticism on the matter, particularly when being taught this subject matter in graduate classes by the experts who work in the field!&lt;/p&gt;&#xA;&lt;p&gt;What I can offer is a partial answer. Regarding how the magnetic field helps, the magnetic field lines can cause incoming solar wind particles to travel a LONGER path to get down lower into the atmosphere. They don't just have to veer poleward, adding more distance. Rather, in addition to that, the particles spiral instead of taking a direct path. This allows for energy loss through various mechanisms including synchrotron radiation (which occurs due to continuous angular acceleration of the charged particles). That alone reduces the energy available for kicking out our own atmospheric molecules into space. Whether or not the scale is significant is another question. In the end, questions like this are really only settled by observations. So, until we have more observations of escape rates for ionized and neutral atmospheric constituents, we won't have a sufficiently reliable answer. The seemingly most robust theory in the world can be wrong due to missing data, since theories are initially based on that very same data.&#xA;So, let's get those satellites up there! :-)&lt;/p&gt;&#xA;" OwnerUserId="7800" LastEditorUserId="6298" LastEditDate="2020-11-28T17:50:05.600" LastActivityDate="2020-11-28T17:50:05.600" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20517" PostTypeId="1" CreationDate="2020-11-27T20:31:06.213" Score="3" ViewCount="82" Body="&lt;p&gt;Given the prominence of the climate crisis, it's important to get some estimates of how much wind power is available in Britain as part of a renewably energised future.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Q. What is yearly average of wind energy available on the landmass on Britain.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;And how much does this work per metre squared?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;More, given that for some they can be unsightly, how much yearly wind energy is available on the island shelf around Britain, say up to 30 km; and again what is the average per square metre? How does this compare with the yearly energy consumption in Britain?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="21427" LastEditorUserId="21427" LastEditDate="2020-12-01T17:48:44.560" LastActivityDate="2020-12-10T08:21:48.223" Title="How much wind power is there roughly in Britain and its surrounding?" Tags="|climate-change|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20519" PostTypeId="1" CreationDate="2020-11-28T23:54:36.113" Score="1" ViewCount="1770" Body="&lt;p&gt;Good afternoon,&lt;/p&gt;&#xA;&lt;p&gt;I'm working on an application makes calls to a weather API for different coordinates across the United States.&lt;/p&gt;&#xA;&lt;p&gt;Instead of getting the weather at each and every point, I'm planning on clustering coordinates together based on how close they are to each other. That way, I can take an average of coordinates and get a single weather forecast that is representative for the group.&lt;/p&gt;&#xA;&lt;p&gt;This raises the question, how close do these points need to be? Would a cluster of radius 50 Miles be sufficient? What about 250?&lt;/p&gt;&#xA;&lt;p&gt;I'm really only gathering these features from my Weather source:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Temperature&lt;/li&gt;&#xA;&lt;li&gt;Category (Rain, Cloudy, Hail, etc.)&lt;/li&gt;&#xA;&lt;li&gt;Visibility&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I don't really need a high degree of precision. In fact, the coordinates I'm using are going to have a  25-50 mile variation from their &amp;quot;true position.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;I'm not a climate scientist, so I apologize if this question is a little rudimentary. I just wanted a second opinion on the topic so I can balance the trade-off between number of API Calls and fidelity to regional weather.&lt;/p&gt;&#xA;" OwnerUserId="21428" LastActivityDate="2020-12-06T06:02:53.927" Title="Over what distance can weather be assumed to be constant?" Tags="|meteorology|weather-forecasting|" AnswerCount="3" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20520" PostTypeId="1" AcceptedAnswerId="20584" CreationDate="2020-11-29T01:32:21.780" Score="1" ViewCount="309" Body="&lt;p&gt;I am not able to upload the map as the file is too large, but I have a map which states there is an over thrust fault. It has two ticks on it indicating downthrow to the NE. The downthrow is pointing towards younger beds. The strike of the fault is parallel to the strike of the surrounding rock units (a fold).&lt;/p&gt;&#xA;&lt;p&gt;What evidence on this map indicates that this is a thrust fault other than the label itself? Should I be thinking/looking at other evidence?&lt;/p&gt;&#xA;" OwnerUserId="21432" LastActivityDate="2020-12-16T16:05:18.147" Title="Identifying thrust faults on a geologic map" Tags="|geology|mapping|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20521" PostTypeId="1" AcceptedAnswerId="20525" CreationDate="2020-11-29T12:34:14.670" Score="4" ViewCount="125" Body="&lt;p&gt;In the past, the Earth's ecosystem has experienced catastrophic mass extinctions as a result of large-scale volcanic eruptions. One example is the event known as the &amp;quot;Great Dying&amp;quot;, 252 million years ago. According to a &lt;a href=&quot;https://nyti.ms/38RIk4M&quot; rel=&quot;nofollow noreferrer&quot;&gt;New York Times article&lt;/a&gt;, massive volcanic eruptions in Siberia ignited fossil fuel deposits. The released CO&lt;sub&gt;2&lt;/sub&gt; led to a warmer climate and acidic oceans, triggering the mass extinction.&lt;/p&gt;&#xA;&lt;p&gt;252 million years is not &lt;em&gt;that&lt;/em&gt; long ago in the overall history of the Earth; it's only 5.6% of the 4.5 billion years Earth has been around.&lt;/p&gt;&#xA;&lt;p&gt;Hence my question: Is the Earth geological much calmer today than 250 million years ago, or are such events simply rare enough that higher mammals and humanity could evolve during one of the lucky lulls?&lt;/p&gt;&#xA;" OwnerUserId="5396" LastActivityDate="2020-11-30T11:29:11.580" Title="Has Earth's geological activity calmed down in the past 250 million years?" Tags="|earth-history|mass-extinction|volcanic-hazard|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20523" PostTypeId="2" ParentId="20519" CreationDate="2020-11-29T19:01:04.637" Score="3" Body="&lt;p&gt;I’m a pilot and deal with meteorology on a day to day basis and have just started to write my first App, albeit with very slow progress -so this is a really interesting question. I’m not sure if you’re aware but virtually all weather observations come from airports and this collective data along with computer modelling forms the basis of all weather reports and forecasts. It will be this data that your API is based on. If you wish to present ‘actual’ conditions your data points need to be close to where the observations are being made for obvious reasons. If your app is for a forecast area then the data points can be much further apart perhaps 30 to 50 miles with any error being time related not necessarily weather. You are most unlikely to be able to cover local effects so some users of your app may be disappointed. If you are interested in gaining specific weather information either actual or forecast in a specific area just type the nearest airport followed by TAF into google. This will give you the forecast, it will also bring up a METAR which are the actual conditions updated hourly.&lt;/p&gt;&#xA;" OwnerUserId="21336" LastActivityDate="2020-11-29T19:01:04.637" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20524" PostTypeId="1" CreationDate="2020-11-30T06:47:57.670" Score="1" ViewCount="20" Body="&lt;p&gt;So there is a company called &lt;a href=&quot;https://www.arcaspace.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Arcaspace&lt;/a&gt; whose launch vehicle gimmick is that by replacing the first stage boosters, which are generally either solid/cryogenic propellants with water/steam propulsion. They do this based on the idea that it's less polluting and cheaper. However from what I'm aware, water is also a &lt;a href=&quot;https://www.nasa.gov/topics/earth/features/vapor_warming.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;greenhouse gas&lt;/a&gt;, meaning that it should count as polluting. And you generally need a lot more water compared to traditional propulsion because of low ISP. While solids and kerolox cycles emit other problematic chemicals, for this question the focus will be specifically on greenhouse gasses.&lt;/p&gt;&#xA;&lt;p&gt;Would the greenhouse emissions of Arca water rocket be better/worse when compared to more traditional rockets?&lt;/p&gt;&#xA;" OwnerUserId="21436" LastActivityDate="2020-11-30T06:47:57.670" Title="Would a water rocket be better/worse for greenhouse effect compared to more standard methalox/kerolox cycles?" Tags="|greenhouse-gases|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20525" PostTypeId="2" ParentId="20521" CreationDate="2020-11-30T11:29:11.580" Score="2" Body="&lt;p&gt;The large-scale volcanic eruptions you mention are called Large Igneous Provinces (LIPs) and are probably linked to mantle plumes. They have been investigated for quite some time now. &lt;a href=&quot;https://doi.org/10.1016/S0264-3707(02)00025-X&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ernst &amp;amp; Buchan (2001)&lt;/a&gt; built a database of 300+ LIPs and used it to analyse their temporal distribution, among other things. Here is the age spectrum they obtained:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FtIfZ.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FtIfZ.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;... ‘well-established’ and ‘probable’ plume head events occur&#xA;throughout the geological record since at least 3500 Ma, and probably&#xA;since 3800 Ma, with no plume-free intervals greater than about 200 Myr&#xA;since 3500 Ma. Plume head arrival does not follow any obvious&#xA;periodicity...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;If you look at the cumulative frequency diagram, there seems to be a increase in event frequency over the last 150 Ma:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Bg8xk.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Bg8xk.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;There are periods when plume activity appears to be more intense than&#xA;at other times. These intervals are identified by steeper slopes on a&#xA;cumulative plot of LIP frequency. The most prominent are at&#xA;2800–2700, 2200–1800, 150–0 Ma and more speculatively at 1300–1100 Ma.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;But as the authors explain, this is a bias due to the fact that the recent record preserves both oceanic and continental LIPs. However, the oceanic crust is consistently recycled (it's nowhere older than ~200 Ma), thus older events are continental LIPs only. If corrected to include only continental LIPs in the recent (&amp;lt; 150 Ma) record, the trend seems &amp;quot;normal&amp;quot; (dotted line).&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2020-11-30T11:29:11.580" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20526" PostTypeId="2" ParentId="20519" CreationDate="2020-11-30T23:31:23.060" Score="-1" Body="&lt;p&gt;It very much depends on what you are modelling. For example, it's well known that tornados require much more precise modelling than say rainfall.&lt;/p&gt;&#xA;&lt;p&gt;In fact, good data on tornado formation is scarce given that they are unpredictable and highly localised phenomena.&lt;/p&gt;&#xA;&lt;p&gt;Even the nationwide scan in the USA that does a scan every five minutes is problematic. Artifacts from this dataset has suggested that they are top down formed whereas recent data from a highly mobile monitoring  equipment has suggested it is exactly the opposite - they are formed bottom-up.&lt;/p&gt;&#xA;" OwnerUserId="21427" LastEditorUserId="21427" LastEditDate="2020-12-06T06:02:53.927" LastActivityDate="2020-12-06T06:02:53.927" CommentCount="16" ContentLicense="CC BY-SA 4.0" />
  <row Id="20527" PostTypeId="2" ParentId="20463" CreationDate="2020-12-01T00:37:29.230" Score="0" Body="&lt;p&gt;You could try Haskell, a modern functional language. It's straight forward to use but perhaps its lack of familiarity may a little intimidating for the uninitiated. It now comes with an extensive library.&lt;/p&gt;&#xA;" OwnerUserId="21427" LastActivityDate="2020-12-01T00:37:29.230" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20528" PostTypeId="2" ParentId="20517" CreationDate="2020-12-01T15:03:12.603" Score="4" Body="&lt;p&gt;&lt;strong&gt;2.2TWe&lt;/strong&gt; on average in the seas...&lt;/p&gt;&#xA;&lt;p&gt;The uk uses less than 350 Gigawatts every year, so the sea can provide about 6 times the current UK energy consumption:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;80 GW in shallow waters (0-25 m)&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;270 GW in seas of depth 25-50m&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;(up to there is sufficient to meet all of the UK's 2016 energy consumption)... There is also:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;790GW in seas of 50-100m&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;1030GW at 100m-700m&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://claverton-energy.com/two-terawatts-average-power-output-the-uk-offshore-wind-resource.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://claverton-energy.com/two-terawatts-average-power-output-the-uk-offshore-wind-resource.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.statista.com/statistics/323381/total-demand-for-electricity-in-the-united-kingdom-uk/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.statista.com/statistics/323381/total-demand-for-electricity-in-the-united-kingdom-uk/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;For onshore resources, you can add another 100GWh.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2020-12-02T03:47:51.153" LastActivityDate="2020-12-02T03:47:51.153" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20529" PostTypeId="1" CreationDate="2020-12-01T16:38:02.487" Score="1" ViewCount="50" Body="&lt;p&gt;I was researching more into the studies done by Kjaer and his team ( &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6235527/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6235527/&lt;/a&gt; ) concerning the hypothesis about the Younger Dryas impact crater named Hiawatha in Greenland and its dating. Another study by Pino et al. ( &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6416299/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6416299/&lt;/a&gt; ) proposes that some of the Younger Dryas Boundary located in Chile could potentially be associated with the impact of Hiawatha and travel of impact ejecta.&lt;/p&gt;&#xA;&lt;p&gt;Regardless of the pending measurements of the exact age of the meteoric rock located under the Ice Sheet to confirm age, my question is this: did the ejecta travel through the atmospheric circulation, which I find to be a possibility due to the polar vortex air currents carrying it over the North Pole, or was it simply from the explosive force which the meteorite was theorized to fall with? I know that with eruptions like St. Helens volcanic ash can circulate far and wide through the atmosphere, but with the amount found in Chile would this more line up with a blanketing of ejecta or just trace amounts finding its way there?&lt;/p&gt;&#xA;&lt;p&gt;Kjær KH, Larsen NK, Binder T, Bjørk AA, Eisen O, Fahnestock MA, Funder S, Garde AA, Haack H, Helm V, Houmark-Nielsen M, Kjeldsen KK, Khan SA, Machguth H, McDonald I, Morlighem M, Mouginot J, Paden JD, Waight TE, Weikusat C, Willerslev E, MacGregor JA. (2018). A large impact crater beneath Hiawatha Glacier in northwest Greenland. Sci Adv. 2018 Nov 14;4(11):eaar8173. doi: 10.1126/sciadv.aar8173.&lt;/p&gt;&#xA;&lt;p&gt;Pino, M., Abarzúa, A. M., Astorga, G., Martel-Cea, A., Cossio-Montecinos, N., Navarro, R. X., Lira, M. P., Labarca, R., LeCompte, M. A., Adedeji, V., Moore, C. R., Bunch, T. E., Mooney, C., Wolbach, W. S., West, A., &amp;amp; Kennett, J. P. (2019). Sedimentary record from Patagonia, southern Chile supports cosmic-impact triggering of biomass burning, climate change, and megafaunal extinctions at 12.8 ka. Scientific reports, 9(1), 4413. &lt;a href=&quot;https://doi.org/10.1038/s41598-018-38089-y&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1038/s41598-018-38089-y&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21439" LastActivityDate="2020-12-08T03:42:00.280" Title="Question Concerning Meteorite Ejecta Travel" Tags="|geology|atmosphere|geochemistry|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20530" PostTypeId="2" ParentId="20512" CreationDate="2020-12-01T16:46:57.763" Score="1" Body="&lt;p&gt;We used this site in one of the projects I did in a geoscience class. &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncdc.noaa.gov/data-access&lt;/a&gt; The current site lists that there is a problem accessing information, but from what I recall the information can be obtained from any weather station across the globe under your parameters, and is compiled in a Microsoft Xcel spreadsheet that was easy to convert to ArcGIS, so would most likely be compatible in open-sourced ones if that is what you are using. Hope this helps.&lt;/p&gt;&#xA;" OwnerUserId="21439" LastActivityDate="2020-12-01T16:46:57.763" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20531" PostTypeId="1" AcceptedAnswerId="20533" CreationDate="2020-12-02T06:22:37.030" Score="1" ViewCount="959" Body="&lt;p&gt;I am working with a program that I want to inform the atmospheric pressure level at &lt;code&gt;atm&lt;/code&gt; and if the pressure is &lt;code&gt;high&lt;/code&gt;, &lt;code&gt;low&lt;/code&gt; or &lt;code&gt;average&lt;/code&gt; in a certain location, but I have not found anywhere on the internet that can give me an idea of how to calculate this. Could anyone tell me &lt;strong&gt;at what level of atmospheric pressure it can be considered low or high?&lt;/strong&gt; is there any specific point? Do I need some more information to calculate this?&lt;/p&gt;&#xA;" OwnerUserId="21440" LastEditorUserId="2470" LastEditDate="2020-12-02T14:21:05.597" LastActivityDate="2020-12-02T17:10:05.447" Title="At what point is the atmospheric pressure considered to be high or low?" Tags="|barometric-pressure|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20532" PostTypeId="1" AcceptedAnswerId="20656" CreationDate="2020-12-02T09:12:08.480" Score="4" ViewCount="131" Body="&lt;p&gt;I work for a local council in the UK. We want to include climate change as a mandatory consideration in all of our decision making. This would require project managers to look at the risk (what adaptation measures we need to consider) and impact (how the project would affect our emissions budget) of any large decisions.&lt;/p&gt;&#xA;&lt;p&gt;I expect that this has been done before, but I can't find a guide or discussion of it anywhere. Please can you suggest sources of information / existing implementations?&lt;/p&gt;&#xA;&lt;p&gt;Sorry if this isn't the most appropriate place to post this, if anybody knows of a more appropriate forum, I'd be happy to go there instead!&lt;/p&gt;&#xA;" OwnerUserId="21441" LastActivityDate="2021-01-07T11:03:27.973" Title="Climate change impact / risk assessment" Tags="|climate-change|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20533" PostTypeId="2" ParentId="20531" CreationDate="2020-12-02T17:10:05.447" Score="3" Body="&lt;p&gt;Usually when you hear someone say &amp;quot;high&amp;quot; or &amp;quot;low&amp;quot; pressure, it is an abbreviated way of saying &amp;quot;local maxima&amp;quot; or &amp;quot;local minima.&amp;quot; And usually that pressure is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_pressure#Mean_sea-level_pressure&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mean Sea Level Pressure&lt;/a&gt;. By that definition, it is a singular point. But if you want to cover an area, you can probably reference a gridded dataset and plot the isobars. Then you can categorize the isobars as &lt;a href=&quot;http://tornado.sfsu.edu/geosciences/classes/m835/TornadoExamples/BasicTornadoStructure/Balanced_flow.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;cyclonic (low pressure in Northern Hemisphere) or anticyclonic (high pressure in Northern Hemisphere)&lt;/a&gt;. Then you can say if the location is enclosed in either, then it is in the respective area. You can make it however complex you want.&lt;/p&gt;&#xA;&lt;p&gt;But if you want to create your own &amp;quot;pressure climatology&amp;quot; then you can probably do what you want to do.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-12-02T17:10:05.447" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20534" PostTypeId="1" CreationDate="2020-12-02T17:11:59.267" Score="3" ViewCount="39" Body="&lt;p&gt;If there had been a La Niña rather than an El Niño in 1991-92, would the sulfur aerosol veil caused by the release of 17-20 megatons of sulfur dioxide during the Pinatubo eruption of June 1991 have caused an even greater amount of global cooling - and with much more social/economic disruption - than it actually did?&lt;/p&gt;&#xA;&lt;p&gt;(It's just because I've read that the global cooling effects of Pinatubo were quite possibly mitigated by the El Niño that followed the eruption - and that the eruption and the El Niño were coincidental and not cause-and-effect.)&lt;/p&gt;&#xA;" OwnerUserId="21442" LastEditorUserId="21442" LastEditDate="2020-12-02T19:02:31.900" LastActivityDate="2020-12-02T19:02:31.900" Title="What if Pinatubo's eruption in 1991 had been followed by a La Niña rather than an El Niño?" Tags="|atmosphere|climate|volcanology|enso|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20535" PostTypeId="2" ParentId="20519" CreationDate="2020-12-03T01:36:51.597" Score="4" Body="&lt;p&gt;Weather is subject to &lt;a href=&quot;https://en.wikipedia.org/wiki/Tobler%27s_first_law_of_geography#:%7E:text=The%20First%20Law%20of%20Geography,specifically%20for%20the%20inverse%20distance&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tobler's First Law of Geography&lt;/a&gt;: Everything is related to everything else, but near things are more related than distant things.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Temperature&lt;/strong&gt;- this changes not only by the feature, but also the day of the year. The winter months, as well as the fall and spring, will have much more drastic temperature changes. This may be due to things like fronts, but is ultimately caused by heating differences from the sun. However, a few miles can yield quite a drastic change. Things become even more complicated when elevation is involved.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Precipitation&lt;/strong&gt;- This is even more variable. Snow can be happening on a mountain, but have rain in a valley. &lt;a href=&quot;https://en.wikipedia.org/wiki/Precipitation#Orographic_effects&quot; rel=&quot;nofollow noreferrer&quot;&gt;Even the side of a mountain can influence how much rain is seen&lt;/a&gt;. I have seen it rain on one side of a building, but not the other. Precipitation is a tricky thing to forecast.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Visibility&lt;/strong&gt; There are several factors that influence visibility. Fog and precipitation are probably the most common meteorological factors. &lt;a href=&quot;https://www.howitworksdaily.com/what-is-the-maximum-distance-the-human-eye-can-see-if-unobstructed-2/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Elevation can really influence your line of sight.&lt;/a&gt; Obviously, visibility is also influenced by the presence of &lt;a href=&quot;https://link.springer.com/chapter/10.1007/978-1-4939-2565-0_61&quot; rel=&quot;nofollow noreferrer&quot;&gt;smoke&lt;/a&gt; as well as &lt;a href=&quot;https://www.weather.gov/safety/wind-dust-storm&quot; rel=&quot;nofollow noreferrer&quot;&gt;dust&lt;/a&gt;.The smaller the particle, the more likely it will obscure vision. And snow tends to be more reflective than rain. Something else that may influence visibility is wind speed, as aforementioned particles can be kicked up from the surface. So visibility will change depending on how all of these change. It may even change depending on the direction you look.&lt;/p&gt;&#xA;&lt;hr&gt;&#xA;&lt;p&gt;All of this to say is that it really depends and there is rule of thumb.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-12-03T01:36:51.597" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20537" PostTypeId="2" ParentId="20440" CreationDate="2020-12-03T19:48:37.563" Score="2" Body="&lt;p&gt;See &lt;a href=&quot;https://space.stackexchange.com/a/39090/28871&quot;&gt;this answer&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Actually &lt;a href=&quot;https://www.space.com/16235-mars-snowflakes-tiny-snow.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;already snows on Mars&lt;/a&gt;. The snow, made of carbon dioxide, has been observed and studied by orbiting spacecraft. Aside from the different chemical composition from the stuff we shovel on Earth, Martian &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; snow also is very finely divided, microscopic in size in fact; likely this is related to the low density of available material and the very fine nature of the dust on which the snowflakes nucleate. In fact studying the snow could provide clues about the atmospheric Martian dust on which it nucleates.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Details are published in the &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016JE005040&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Journal of Geophysical Research&lt;/em&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In addition:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Indirect evidence for water ice snow has also been found. According to an article published in &lt;a href=&quot;https://www.nature.com/articles/ngeo3008&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Nature&lt;/em&gt;&lt;/a&gt;, mixing layers have been identified from orbiting spacecraft and water-ice precipitation signatures have been found by the Phoenix lander. Simulations show that such signatures are consistent with snow formation, with the water-ice snow expected to fall at night (as temperatures cool and the atmosphere can retain less water vapor). The arcticle does not claim any direct detection of water-ice snow.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2021-03-17T00:09:09.923" LastActivityDate="2021-03-17T00:09:09.923" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20538" PostTypeId="2" ParentId="19110" CreationDate="2020-12-03T23:31:46.440" Score="0" Body="&lt;p&gt;The facile answer is &amp;quot;Venus's  atmosphere has many times the mass of Earth's atmosphere because it has many times the amount of gas&amp;quot;. Which makes us ask wonder why &lt;em&gt;that&lt;/em&gt; is.&lt;/p&gt;&#xA;&lt;p&gt;Many planetary scientists have interpreted the relatively even distribuion of impact craters on the surface of Venus as a sign that the planet was resurfaced in some catastrophic event 500-700 million years ago:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;From the craters visible in Magellan's Venus maps, scientists believe they are looking at a relatively young planetary surface, perhaps about 500 million years old. Since Venus formed at the same time as Earth 4.6 billion years ago, some event or events 500 million years ago must have resurfaced the planet. Scientists believe that this may have been the work of massive outpourings of lava from planet-wide volcanic eruptions.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;-NASA, &lt;a href=&quot;https://www2.jpl.nasa.gov/magellan/fact1.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Magellan Summary Sheet&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The initial estimate of 500 million years has since been pushed back to a bit older, around 700 million years. (Earth was in a snowball phase about this time).&lt;/p&gt;&#xA;&lt;p&gt;Whether the event on Venus was purely volcanic or the result of an impact &lt;a href=&quot;https://image.gsfc.nasa.gov/poetry/venus/q1443.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;is still an issue of debate&lt;/a&gt;. Regardless, this was a volcanic event many orders of magnitude greater than the Siberian Traps whose gases caused the end-Permian extinction on Earth.&lt;/p&gt;&#xA;&lt;p&gt;Earth's atmosphere is replenished from volcanic outgassing. We can speculate that the catastrophe released an enormous amount of gas into Venus's atmosphere.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Between 700 and 750 million years ago, a near-global resurfacing event triggered the release of carbon dioxide from rock on the planet, which transformed its climate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;(Wikipedia: &lt;a href=&quot;https://en.wikipedia.org/wiki/Life_on_Venus&quot; rel=&quot;nofollow noreferrer&quot;&gt;Life on Venus&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2020-12-03T23:39:54.817" LastActivityDate="2020-12-03T23:39:54.817" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20539" PostTypeId="1" CreationDate="2020-12-03T23:48:05.387" Score="6" ViewCount="368" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Desert_greening&quot; rel=&quot;noreferrer&quot;&gt;Desert greening&lt;/a&gt; is the conversion of deserts into moister environments with more vegetation. This could be used to combat desertification and (by sequestering CO2) climate change, and also to increase the amount of arable land.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Lzd4j.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Lzd4j.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;(Image from the Wikipedia article on desert greening; credit to Mike Baird)&lt;/p&gt;&#xA;&lt;p&gt;This obviously requires a water source. One potential water source (mentioned in the previously linked page under the &amp;quot;Water&amp;quot; section) is seawater (or other saltwater, e.g. from saltwater aquifers), which can be used directly by halophytic plants. &lt;a href=&quot;https://en.wikipedia.org/wiki/Water_distribution_on_Earth&quot; rel=&quot;noreferrer&quot;&gt;97.5% of Earth's water is saltwater&lt;/a&gt;, making this more abundant by far than freshwater. Using saltwater for irrigation is already being done in &lt;a href=&quot;https://www.salineagricultureworldwide.com/saline-agriculture&quot; rel=&quot;noreferrer&quot;&gt;saline agriculture&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;This method would avoid conflicts with use of freshwater (&lt;a href=&quot;https://en.wikipedia.org/wiki/Water_scarcity&quot; rel=&quot;noreferrer&quot;&gt;an increasingly scarce resource&lt;/a&gt;) and would be cheaper and less energy-consuming than using desalinated water. &lt;a href=&quot;https://envirotecmagazine.com/2019/03/07/coastal-wetlands-capture-more-carbon-as-seas-rise/&quot; rel=&quot;noreferrer&quot;&gt;Mangroves and saltmarshes are more effective at sequestering CO2&lt;/a&gt; than other types of ecosystems. And this would also have economic benefits if the plant species used have useful products like food, fibre etc.&lt;/p&gt;&#xA;&lt;p&gt;How feasible is this idea? What challenges would this face? One challenge I can think of is the limited number of plant species able to grow on saltwater.&lt;/p&gt;&#xA;" OwnerUserId="21448" LastActivityDate="2022-04-29T07:03:25.317" Title="Could saltwater be useful for greening deserts and sequestering CO2?" Tags="|water|desert|geoengineering|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20540" PostTypeId="2" ParentId="20539" CreationDate="2020-12-04T13:15:39.823" Score="0" Body="&lt;p&gt;May the right aproach is, improve the process to turn saltwater into fresh water cause the only thing that i know which can be food and has salt tolerance is palm tree, mangrooves demmand a highly amount of seawater meeting a river&lt;/p&gt;&#xA;" OwnerUserId="21449" LastActivityDate="2020-12-04T13:15:39.823" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20541" PostTypeId="2" ParentId="20539" CreationDate="2020-12-05T03:59:48.620" Score="1" Body="&lt;p&gt;The biggest detriment to keeping deserts green is of course water. With rainfall in the desert limited, afforestation is a tricky and potentially dangerous thing to do. China tried this for decades with afforestation efforts, planting billions of trees in steppe regions of China and Mongolia, only to later worsen because the trees consumed too much ground water and lowered the water table.&#xA;&lt;a href=&quot;https://www.researchgate.net/publication/5442299_Why_Large-Scale_Afforestation_Efforts_in_China_Have_Failed_To_Solve_the_Desertification_Problem&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/publication/5442299_Why_Large-Scale_Afforestation_Efforts_in_China_Have_Failed_To_Solve_the_Desertification_Problem&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It's possible you could harvest ocean water as a source of humidity, the water evaporating would generate atmospheric moisture but where it will land? is the question.&#xA;Seawater humidifiers could do it. Basically a greenhouse or solar still. The difference is you direct the humidity downward where it percolates into the soil.&lt;a href=&quot;https://i.stack.imgur.com/H9O3c.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/H9O3c.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Another example are drought tolerant trees, like acacias, planted in the Sahara. These may very well sustain themselves with their ability to settle and accumulate more water. They provide shade and so prevent the surface soil from overheating, which has several benefits...&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;With cooler soil, the little soil moisture that falls here can percolate into the ground without evaporating&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;It shades wildlife  (wintering birds) from extreme heat (who in turn produce fertilzer i.e. guano)&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Expands wintering bird habitat&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Produces edible fruit's&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-12-05T03:59:48.620" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20542" PostTypeId="1" CreationDate="2020-12-05T15:57:00.017" Score="1" ViewCount="280" Body="&lt;p&gt;I'm aware that oceanic crust always sub-ducts to continental crust, but surely the geologic forces pushing the ridge apart in the first place isn't just going to turn off, right?&lt;/p&gt;&#xA;&lt;p&gt;Any answers would be greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="14814" LastActivityDate="2020-12-05T19:19:30.187" Title="What happens when a mid-ocean ridge sub-ducts underneath continental crust?" Tags="|geology|plate-tectonics|volcanology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20543" PostTypeId="2" ParentId="20542" CreationDate="2020-12-05T19:19:30.187" Score="1" Body="&lt;p&gt;We probably can't say that any one thing will happen in every instance.  The particular effects of any one such subduction will probably depend on the event's geometry and the continental rocks doing the subducting.&lt;/p&gt;&#xA;&lt;p&gt;That said, we can talk about a famous instance of this, when parts of the East Pacific Rise (between the Pacific and &lt;a href=&quot;https://en.wikipedia.org/wiki/Farallon_Plate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Farallon&lt;/a&gt; plates) first started going under North America about 30 Ma ago.&lt;/p&gt;&#xA;&lt;p&gt;Subduction itself is a destructive process: oceanic sediments and water lower the melting point of the crust being subducted, so the subducted plate melts.&lt;/p&gt;&#xA;&lt;p&gt;So, for the most part, the Pacific-Farallon rifting centers were just swallowed up, and we don't consider the Farallon plate to exist anymore, just its remnants, such as the Juan de Fuca and Cocos plates.  A large transform fault, the San Andreas Fault, formed in the gap.&lt;/p&gt;&#xA;&lt;p&gt;However, the tendency to rift is still there: A bunch of previously North American continental crust was rifted off onto the underlying Pacific Plate oceanic crust, forming Baja California, and the San Andreas Fault adjusted itself to meet the rift. This was more likely a recent extension of the rift north from the Rivera triple junction than remnant Farallon slab pull under North America.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/boY8Q.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/boY8Q.jpg&quot; alt=&quot;Farallon subduction&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: USGS via Wikimedia Commons - Public Domain&lt;/p&gt;&#xA;" OwnerUserId="6467" LastActivityDate="2020-12-05T19:19:30.187" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20545" PostTypeId="1" AcceptedAnswerId="20552" CreationDate="2020-12-06T03:27:00.517" Score="1" ViewCount="51" Body="&lt;p&gt;CNN's &lt;a href=&quot;https://edition.cnn.com/2020/12/03/asia/china-weather-modification-cloud-seeding-intl-hnk/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;China to expand weather modification program to cover area larger than India&lt;/a&gt; ends with the following sentence:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;While China has not yet shown signs of 'unilaterally' deploying geoengineering projects on the ground, the scale of its weather modification and other massive engineering projects, including mega-dam projects (such as the Three Gorges), suggests China is willing to deploy large-scale geoengineering schemes to tackle the impacts of climate change and achieve its Paris targets.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and the scope of my question is limited to the Earth Science aspects of geoengineering projects that could &amp;quot;..tackle the impacts of climate change and achieve... Paris (agreement) targets&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;To my knowledge the &lt;a href=&quot;https://en.wikipedia.org/wiki/Paris_Agreement&quot; rel=&quot;nofollow noreferrer&quot;&gt;Paris Agreement&lt;/a&gt; primarily focuses on the &lt;em&gt;reduction of greenhouse gas emission&lt;/em&gt; itself, so I would think that geoengineering solutions might involve removing gases already emitted in the form of new biomass or as gas in geological sequestration sites, or by producing energy with a technology having a lower greenhouse emission rate.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Is that so? If so, what are specific examples?&lt;/li&gt;&#xA;&lt;li&gt;Since the same article discusses both cloud seeding for precipitation induction and the dispersal of reflective particles to reduce global warming earlier, could there be some atmospheric dispersal technology that could help a country &amp;quot;...achieve its Paris targets&amp;quot;?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2020-12-08T02:33:51.467" Title="What potential geoengineering technologies could help a country &quot;achieve its Paris (agreement) targets&quot;?" Tags="|climate-change|co2|greenhouse-gases|geoengineering|methane|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20546" PostTypeId="1" CreationDate="2020-12-06T08:12:40.510" Score="4" ViewCount="453" Body="&lt;p&gt;With the disclaimer than I am not a scientist, my understanding is that the earth developed a surplus of atmospheric oxygen over the eons because a small percentage of photosynthetic organisms were fossilized instead of decomposing (therefore releasing a net production of oxygen). The oxygen produced by forests is a zero gain, since the forests consume their own oxygen through forest fires and decomposition.  When we burn fossil fuels, we lose these net oxygen molecules. Does that imply that the world is at risk of running out of atmospheric oxygen? Aside for other environmental concerns, can the continued use of fossil fuels create an oxygen crisis?&#xA;Put in other words, do the oceans produce enough oxygen to account for our current use of fossil fuels and population growth?&lt;/p&gt;&#xA;" OwnerUserId="21456" LastActivityDate="2020-12-10T23:30:41.867" Title="Are we consuming more oxygen than the world is producing due to fossil fuels?" Tags="|fossil-fuel|oxygen|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20547" PostTypeId="2" ParentId="20529" CreationDate="2020-12-06T10:10:39.027" Score="1" Body="&lt;p&gt;The research doesn't provide enough information to specify the displacement process of a 0.1mm spherule over 12,000 kilometers from North Greenland to Chile.&lt;/p&gt;&#xA;&lt;p&gt;If the suggested impact was from Greenland, the space rock would have hit 800 to 1200 meters of ice at perhaps 10km/s which is the average for that kind of event.&lt;/p&gt;&#xA;&lt;p&gt;Mount St Helens was about 0.25 km&lt;sup&gt;3&lt;/sup&gt; of ejecta, and the Greenland impact was a lot higher, i.e. &lt;a href=&quot;https://advances.sciencemag.org/content/4/11/eaar8173&quot; rel=&quot;nofollow noreferrer&quot;&gt;20km&lt;sup&gt;3&lt;/sup&gt; of vaporized rock&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Volcanoes send the energy out over many hours, whereas a YD meteorite would convert the energy relatively fast, perhaps mostly in the first 2 seconds. The thermal energy would have been very high, and the ejecta would have reached every level of the stratosphere, and the earthquakes would have emptied some lakes out in North America and left some major destruction fields in North America.&lt;/p&gt;&#xA;&lt;p&gt;The same atmospheric displacement effects for all kinds of recent volcanoes would have been out measured considerably by a YT event.&lt;/p&gt;&#xA;&lt;p&gt;Perhaps further studies will change the impactor site from the Greenland one which is perhaps 200k years old, to one in the Southern Hemisphere. At the moment, the evidence is so fleeting that the Nature article you gave has only generated a few lines of text on Wiki.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="2470" LastEditDate="2020-12-08T03:42:00.280" LastActivityDate="2020-12-08T03:42:00.280" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20548" PostTypeId="1" CreationDate="2020-12-06T22:57:28.517" Score="1" ViewCount="95" Body="&lt;p&gt;I’ve asked this on Worldbuilding, but can anyone find/make me a formula that can be used to predict the mean temperature of a planet, while factoring in greenhouse effect?&lt;/p&gt;&#xA;" OwnerUserId="21461" LastActivityDate="2020-12-07T01:26:38.610" Title="Find planetary temperature" Tags="|climate|temperature|greenhouse-gases|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20549" PostTypeId="2" ParentId="20548" CreationDate="2020-12-07T01:26:38.610" Score="3" Body="&lt;p&gt;What you are looking for is called a &lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_model#Zero-dimensional_models&quot; rel=&quot;nofollow noreferrer&quot;&gt;zero-dimensional climate model&lt;/a&gt;. The equation without the Greenhouse effect is simple, though with a lot of simplifications, &lt;a href=&quot;https://www.e-education.psu.edu/meteo469/node/137#:%7E:text=In%20this%20very%20simple%20model,model%20as%20%27zero%20dimensional%27.&quot; rel=&quot;nofollow noreferrer&quot;&gt;one with a very crude, linearized, Greenhouse effect is possible.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-12-07T01:26:38.610" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20550" PostTypeId="1" CreationDate="2020-12-07T18:34:05.020" Score="5" ViewCount="167" Body="&lt;p&gt;&lt;strong&gt;Question&lt;/strong&gt;: &lt;br /&gt;&#xA;Is there scientific consensus on the existence of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Iris_hypothesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iris Effect&lt;/a&gt; and whether it is a positive or negative feedback mechanism? If so, can you refer to a recent publication?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Background&lt;/strong&gt;: &lt;br /&gt;&#xA;In 2001 Lindzen et. al. published this: &lt;a href=&quot;https://journals.ametsoc.org/view/journals/bams/82/3/1520-0477_2001_082_0417_dtehaa_2_3_co_2.xml?tab_body=fulltext-display&quot; rel=&quot;nofollow noreferrer&quot;&gt;Does the Earth Have an Adaptive Infrared Iris?&lt;/a&gt;&#xA;They propose that current climate models (back in 2001) may underestimate the influence of a negative cloud feedback which today is called the iris effect (negative feedback: feedback that reduces an initial warming).&lt;/p&gt;&#xA;&lt;p&gt;In brief, the iris effect is proposed to work as follows: A global warming will lead to an enhanced tropical circulation and thus lead to more subsiding air in the subtropics. The subsiding air will lead to fewer (cirrus) clouds and thus, allows outgoing long wave radiation to evade to space. Therefore, temperatures will decrease.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Own findings&lt;/strong&gt;: &lt;br /&gt;&#xA;I did a little research myself which leads me to think that there is no consensus whether the feedback is positive or negative but there are many studies that at least hint the existence of the iris effect. For example I found this: &amp;quot;The decrease of anvil coverage with warming can be associated with both an increase in the outgoing long-wave radiation and a decrease in planetary albedo.&amp;quot; - &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GL089059&quot; rel=&quot;nofollow noreferrer&quot;&gt;Saint-Lu et. al., 2020&lt;/a&gt;,&lt;br /&gt;&#xA;and this: &lt;a href=&quot;https://www.nature.com/articles/ngeo2414&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mauritsen, Stevens, 2015&lt;/a&gt;.&lt;br /&gt;&#xA;My hope is, however, that there is someone with more detailed knowledge who can help me. Sorry in advance if this question is too broad and &amp;quot;unspecific&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Please keep in mind that my question addresses the iris effect only. I'm aware that the effect of clouds on radiation is a highly active are of research. See e.g. &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter07_FINAL-1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC on clouds and aerosols&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="18833" LastEditorDisplayName="user1066" LastEditDate="2020-12-09T02:12:55.783" LastActivityDate="2020-12-09T02:12:55.783" Title="Is there scientific consensus on the existence of the iris effect" Tags="|climate-change|climate|clouds|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20551" PostTypeId="2" ParentId="20413" CreationDate="2020-12-08T01:55:26.250" Score="3" Body="&lt;p&gt;One of the flaws with using subduction zones as dumps for toxic chemicals so they can be broken down by heat and pressure at depth is the rate of sinking of the subducting plate.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.worldatlas.com/articles/what-is-the-process-of-subduction.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Subduction&lt;/a&gt; is a very slow process, generally between 2 and 8 centimeters per year. Any toxic material is going to hang around the interface for a very long time, with the potential to contaminate the sea bed and farther beyond, through transportation via submarine currents, for a very long time.&lt;/p&gt;&#xA;&lt;p&gt;Also, depending on the subduction zone used, the toxic material may resurface relatively quickly, particularly where &lt;a href=&quot;https://en.wikipedia.org/wiki/Island_arc&quot; rel=&quot;nofollow noreferrer&quot;&gt;island arcs&lt;/a&gt; are created. This would contaminate the islands made in such environments.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-12-08T01:55:26.250" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20552" PostTypeId="2" ParentId="20545" CreationDate="2020-12-08T02:33:51.467" Score="1" Body="&lt;p&gt;I think the third paragraph of the article hints at what might be the thinking.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In the next five years, the total area covered by artificial rain or snowfall will reach 5.5 million sq km, while over 580,000 sq km (224,000 sq miles) will be covered by hail suppression technologies. The statement added that the program will help with disaster relief, agricultural production, emergency responses to forest and grassland fires, and dealing with unusually high temperatures or droughts.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Firstly, rain will absorb some CO&lt;sub&gt;2&lt;/sub&gt; by creating small amounts of &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonic_acid&quot; rel=&quot;nofollow noreferrer&quot;&gt;carbonic acid&lt;/a&gt; (H&lt;sub&gt;2&lt;/sub&gt;CO&lt;sub&gt;3&lt;/sub&gt;). Agricultural production would remove some CO&lt;sub&gt;2&lt;/sub&gt;. Reduction of CO&lt;sub&gt;2&lt;/sub&gt; production via the possible prevention of grass &amp;amp; forest fires. This would also be aided by the supposed reduction of temperatures and droughts. With sufficient rain to ensure the Three Gorges Dam is always full, potentially consistently reliable hydroelectricity could be achieved, thus reducing the amount of CO&lt;sub&gt;2&lt;/sub&gt; producing energy sources used for energy production.&lt;/p&gt;&#xA;&lt;p&gt;Finally, hail suppression technologies were mentioned. By eliminating hail one eliminates the potential for damaging hail to occur thus reducing the need to manufacture building products to repair buildings damaged by hail. It also prevents crop damage by hail thus eliminating the need to plant replacement crops.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-12-08T02:33:51.467" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20554" PostTypeId="1" CreationDate="2020-12-08T22:59:27.630" Score="4" ViewCount="187" Body="&lt;p&gt;If somehow we were to move the Earth's axis of rotation to, say, Mexico, making some spot in Mexico  effectively the North Pole, would this change how the continental plates drift over time, thereby changing the shape of a World Map a hundred million years from now (as compared to how that map would look had we not changed the axis)?&lt;/p&gt;&#xA;&lt;p&gt;I'm wondering about the effects of so called centrifugal forces and so on, or any other effects I might not be thinking of.&lt;/p&gt;&#xA;" OwnerUserId="21468" LastEditorUserId="21468" LastEditDate="2020-12-09T03:32:23.957" LastActivityDate="2020-12-21T02:21:11.380" Title="Does the position of the Earth's axis affect the position and shape of its continents?" Tags="|mapping|continent|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20556" PostTypeId="2" ParentId="20517" CreationDate="2020-12-09T14:47:19.573" Score="0" Body="&lt;p&gt;Regarding renewable energies, there is a great book freely available:&#xA;&lt;a href=&quot;https://www.withouthotair.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.withouthotair.com/&lt;/a&gt;&#xA;written by David MacKay. At the time he was the Regius Professor of Engineering at the University of Cambridge.&lt;/p&gt;&#xA;&lt;p&gt;He estimated that onshore you can produce (realistically)&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;if we covered the windiest 10% of the country with windmills&#xA;(delivering 2 W/m2), we would be able to generate 20 kWh/d per person,&#xA;which is half of the power used by driving an average fossil-fuel car&#xA;50 km per day.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;(see &lt;a href=&quot;https://www.withouthotair.com/c4/page_32.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.withouthotair.com/c4/page_32.shtml&lt;/a&gt; and following pages)&lt;/p&gt;&#xA;&lt;p&gt;Consumption in the UK was, at the time (2009), on average 195 kWh per day per person.&lt;/p&gt;&#xA;" OwnerUserId="5887" LastEditorUserId="5887" LastEditDate="2020-12-10T08:21:48.223" LastActivityDate="2020-12-10T08:21:48.223" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20557" PostTypeId="2" ParentId="20546" CreationDate="2020-12-10T23:11:49.190" Score="2" Body="&lt;p&gt;Yes, atmospheric oxygen is being depleted by fossil fuel burning.&lt;/p&gt;&#xA;&lt;p&gt;From &lt;a href=&quot;https://cdiac.ess-dive.lbl.gov/trends/oxygen/modern_records.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://cdiac.ess-dive.lbl.gov/trends/oxygen/modern_records.html&lt;/a&gt; -&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Oxygen concentrations are currently declining at roughly 19 per meg&#xA;per year, or about 4 ppm per year. One &amp;quot;per meg&amp;quot; indicates one&#xA;molecule out of 1,000,000 oxygen molecules, or roughly one molecule in&#xA;4.8 million molecules of air.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;And -&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;fossil fuel burning is depleting atmospheric oxygen at a rate of almost 1000 tons per second. There are about 32 million seconds in a&#xA;year, so that somewhere around 30 billion tons of O2 are being&#xA;converted to CO2 annually.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Because the quantities of O2 are very large the reduction is small in comparison. From same source -&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;There are about 1,200,000 billion metric tons of O2 in the atmosphere,&#xA;so we can keep burning fossil fuels at the present rate for 40,000&#xA;years before we run out of oxygen. By then, all of the world's fossil&#xA;fuel supply will have long since been exhausted.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2020-12-10T23:11:49.190" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20558" PostTypeId="2" ParentId="20546" CreationDate="2020-12-10T23:30:41.867" Score="1" Body="&lt;p&gt;Since pre-industrial times &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; has increased from 280 to 415 ppm. Considering only carbon (ignoring the hydrogen in hydrocarbons), atmospheric &lt;span class=&quot;math-container&quot;&gt;$O_2$&lt;/span&gt; decreased by the same amount, 135 ppm. The remaining FF are not much more than what has been burned, so the &lt;span class=&quot;math-container&quot;&gt;$O_2$&lt;/span&gt; consumed will only be a tiny fraction of atmospheric &lt;span class=&quot;math-container&quot;&gt;$O_2$&lt;/span&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Oil will end by 2052   – 30 years time&lt;br /&gt;&#xA;Gas will end by 2060  – 40 years time&lt;br /&gt;&#xA;Coal will last till 2090 –   70 years time&lt;br /&gt;&#xA;&lt;a href=&quot;https://mahb.stanford.edu/library-item/fossil-fuels-run/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://mahb.stanford.edu/library-item/fossil-fuels-run/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I think that most fossil carbon is not in concentrated deposits that could be mined, so it is not included in the above estimates.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2020-12-10T23:30:41.867" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20559" PostTypeId="1" CreationDate="2020-12-09T22:41:04.310" Score="1" ViewCount="67" Body="&lt;p&gt;I know that earth magnetic field is like a shield for Coronal particles. But it will generate magnetic induction&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qkr7b.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qkr7b.jpg&quot; alt=&quot;Geomagnetic Storm&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Is my eMMC Storage vulnerable?&lt;br /&gt;&#xA;Will aluminium foil protect my data?&lt;/p&gt;&#xA;" OwnerDisplayName="alecxs" LastEditorUserId="2958" LastEditDate="2020-12-13T19:29:58.590" LastActivityDate="2020-12-13T19:29:58.590" Title="Does Coronal Mass Ejection (CME) affect my eMMC Storage?" Tags="|electromagnetism|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20561" PostTypeId="2" ParentId="20554" CreationDate="2020-12-11T13:48:21.277" Score="1" Body="&lt;p&gt;This is an idea that we can consider &amp;quot;wild&amp;quot;.&#xA;Or even better, &lt;em&gt;untamed&lt;/em&gt;. Every then and now there are researchers trying to address the questions, but the proof have not been conclusive up to now (as far as I know).&lt;/p&gt;&#xA;&lt;p&gt;If you have sufficient knowledge, you may try to go through this peer-reviewed paper&#xA;Riguzzi et al, (2009) &lt;em&gt;Can Earth's rotation and tidal despinning drive plate tectonics?&lt;/em&gt;&#xA;&lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0040195109003321#&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/abs/pii/S0040195109003321#&lt;/a&gt;!&lt;/p&gt;&#xA;&lt;p&gt;It has been cited 67 times, which is a small number, but not negligible.&#xA;I would say your question at the moment has only a possible answer: &lt;strong&gt;maybe.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;But it is a good question and maybe someone can provide a better answer!&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2020-12-11T13:48:21.277" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20562" PostTypeId="2" ParentId="20413" CreationDate="2020-12-11T13:56:13.107" Score="1" Body="&lt;p&gt;Your idea may seem weird, but it is what has been done for decades in the US and elsewhere.&lt;/p&gt;&#xA;&lt;p&gt;You do not need to reach the centre of the earth. 3 to 4 km may suffice (Terms and Conditions apply ...)&lt;/p&gt;&#xA;&lt;p&gt;Have a look for example at the Rocky Mountain Arsenal disposal experience in Colorado USA). In the 60s, the US military had to dispose tons of chemical and batteriological byproducts from their production.&#xA;You may find details about the site here &lt;a href=&quot;https://en.wikipedia.org/wiki/Rocky_Mountain_Arsenal&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Rocky_Mountain_Arsenal&lt;/a&gt;&#xA;but what makes it interesting regarding your question is that the deep disposal of fluids led to ... earthquakes.&#xA;See relevant publication from USGS archives:&#xA;&lt;a href=&quot;https://earthquake.usgs.gov/static/lfs/research/induced/Healy-et-al-1968-Science-(New-York-NY).pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earthquake.usgs.gov/static/lfs/research/induced/Healy-et-al-1968-Science-(New-York-NY).pdf&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Denver area was (and still is) expected to be tectonically quiet, with no earthquakes, and there are convincing proof that the disposal of fluids (toxic, heavy metals, batteriological byproducts, who know what they did dispose) induced some strong earthquakes up there.&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2020-12-11T13:56:13.107" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20563" PostTypeId="2" ParentId="20499" CreationDate="2020-12-12T08:50:06.973" Score="0" Body="&lt;p&gt;Among all continents, during the Pangea separation, India traveled the maximum distance. At&#xA;the beginning the convergence velocity of India was very high (&lt;span class=&quot;math-container&quot;&gt;$100-125$&lt;/span&gt; mm/yr, from &lt;span class=&quot;math-container&quot;&gt;$70$&lt;/span&gt; to &lt;span class=&quot;math-container&quot;&gt;$55$&lt;/span&gt;Ma).&#xA;The velocity slowed down to &lt;span class=&quot;math-container&quot;&gt;$70-75$&lt;/span&gt;mm/yr after the collision (&lt;span class=&quot;math-container&quot;&gt;$55-20$&lt;/span&gt;Ma). In this time (&lt;span class=&quot;math-container&quot;&gt;$55-20$&lt;/span&gt;Ma) most&#xA;thrust faults in Himalaya developed due to extreme compression. The convergence velocity reduced to&#xA;about &lt;span class=&quot;math-container&quot;&gt;$40-50$&lt;/span&gt;mm/yr after &lt;span class=&quot;math-container&quot;&gt;$20$&lt;/span&gt; Ma. Since &lt;span class=&quot;math-container&quot;&gt;$20$&lt;/span&gt; Ma, the mantle-convection below the Indian Plate, that dragged India (from ~&lt;span class=&quot;math-container&quot;&gt;$70-20$&lt;/span&gt; Ma) to form Himalaya, could not drag the Indian plate further due to (i)&#xA;the collision and (ii) the fact that the Tibetan asthenosphere acted as a buttress. The mantle rocks&#xA;below the Indian plate, being elastic-viscous in terms of rheology, started relaxing (viscous relaxation),&#xA;which significantly reduced the compressive force. The relaxing nature of the Mantle below the Indian&#xA;plate also transmitted to the crust, expression of which is the formation of normal faults after &lt;span class=&quot;math-container&quot;&gt;$20$&lt;/span&gt; Ma.&lt;/p&gt;&#xA;&lt;p&gt;The ages could be &lt;span class=&quot;math-container&quot;&gt;$\pm 5$&lt;/span&gt; Ma.&lt;/p&gt;&#xA;" OwnerUserId="21396" LastActivityDate="2020-12-12T08:50:06.973" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20565" PostTypeId="1" CreationDate="2020-12-13T13:07:10.067" Score="4" ViewCount="568" Body="&lt;p&gt;Plenty of answers answer the question &lt;em&gt;that&lt;/em&gt; it happens but I can't find a good answer as to &lt;em&gt;why&lt;/em&gt; the wind shifts during the passing of a front.&#xA;For an extreme example see:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/gE2hc.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gE2hc.png&quot; alt=&quot;a graph of an abrubt wind shift&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(in Dutch, x is hours and y is wind direction in degrees)&lt;br /&gt;&#xA;Where a passing cold front moved the wind directon from south to northwest.&lt;/p&gt;&#xA;&lt;p&gt;The other question provides a very broad answer as to why wind changes &lt;em&gt;in general&lt;/em&gt; and the answers there are applicable &lt;em&gt;in general&lt;/em&gt;. My question is about the specific circumstances of a thermal front and what causes the change in the balance of forces to suddenly allow or force the direction of the wind to change direction.&lt;/p&gt;&#xA;" OwnerUserId="21485" LastEditorUserId="21485" LastEditDate="2020-12-15T21:23:36.853" LastActivityDate="2020-12-15T21:23:36.853" Title="Why does wind direction change in a front?" Tags="|meteorology|wind|" AnswerCount="1" CommentCount="6" ClosedDate="2020-12-15T20:08:26.203" ContentLicense="CC BY-SA 4.0" />
  <row Id="20566" PostTypeId="2" ParentId="20485" CreationDate="2020-12-13T13:53:34.427" Score="1" Body="&lt;p&gt;In the case of gravity, it depends on where you look, literally.  On the surface of a typical planet gravitational fields have hardly any effect on chemistry.  But if the planet is big and massive enough so that the pressure built up by gravity throughout the mass pushes it into a rounded shape, chances are that pressure is also affecting the chemistry of its rocks.&lt;/p&gt;&#xA;&lt;p&gt;In the case of Earth, this shows up as the formation of &lt;a href=&quot;http://www.spring8.or.jp/en/news_publications/publications/scientific_results/earth_science/topic21&quot; rel=&quot;nofollow noreferrer&quot;&gt;silicate phases in the mantle that would not appear naturally on the surface&lt;/a&gt;, chief among them the &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Silicate_perovskite&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;silicate perovskites&lt;/strong&gt;&lt;/a&gt; in which each silicon atom is bonded to six oxygen atoms instead of four.  The illustration below shows how the silicate rocks change from the from olivine (which has the &amp;quot;normal&amp;quot; silicate bonding) into perovskite and other phases where the silicon has become bonded to the additional oxygen neighbors.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/XOGcY.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&#xA;&lt;a href=&quot;http://www.spring8.or.jp/en/news_publications/publications/scientific_results/earth_science/topic21&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Silicates are not the only phases affected by the gravitationally generated pressure inside Earth.  Carbon is affected too, leading to the (natural) formation of diamonds -- which often have inclusions of those high-pressure silicate phases trapped inside, thus providing verification of these gravity/pressure-induced phases.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2020-12-18T13:37:52.043" LastActivityDate="2020-12-18T13:37:52.043" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20567" PostTypeId="1" AcceptedAnswerId="20568" CreationDate="2020-12-13T18:58:03.147" Score="2" ViewCount="59" Body="&lt;p&gt;I study about fluvial terraces. However, resources related to this topic are limited. When I searched fluvial terraces in geomorphology books, I cannot find anything, but I find river terraces. My English is not good, so I am not sure fluvial terraces and river terraces are same. Do these two terms represent the same topic, please help me?&lt;/p&gt;&#xA;" OwnerUserId="21486" LastEditorUserId="2470" LastEditDate="2020-12-13T19:33:17.463" LastActivityDate="2020-12-13T20:12:29.937" Title="Are Fluvial and River Terraces the same?" Tags="|geology|rivers|geomorphology|lakes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20568" PostTypeId="2" ParentId="20567" CreationDate="2020-12-13T20:12:29.937" Score="4" Body="&lt;p&gt;In English, the word &lt;a href=&quot;https://www.thefreedictionary.com/fluvial&quot; rel=&quot;nofollow noreferrer&quot;&gt;fluvial&lt;/a&gt; comes from the Latin word for river.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Fluvial_processes&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fluvial processes&lt;/a&gt; are processes associated with rivers or streams and the deposits and forms created by them.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/River_terraces_(tectonic%E2%80%93climatic_interaction)&quot; rel=&quot;nofollow noreferrer&quot;&gt;River terraces&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Fluvial_terrace&quot; rel=&quot;nofollow noreferrer&quot;&gt;fluvial terraces&lt;/a&gt; are the same thing.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-12-13T20:12:29.937" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20570" PostTypeId="1" AcceptedAnswerId="20575" CreationDate="2020-12-14T05:20:01.527" Score="19" ViewCount="4317" Body="&lt;p&gt;I originally thought that you can only find certain things like iron, copper, and other things in certain places in the world and deep in mines but I saw in a few YouTube videos that you can find iron in rocks just laying on the ground. I searched for where copper comes from and it seems that, even though a lot of it comes from Chile, it can be found everywhere in smaller amounts. Is this true? Could I walk out into the woods right now anywhere in the world and find copper and iron?&lt;/p&gt;&#xA;" OwnerUserId="21488" LastEditorUserId="725" LastEditDate="2020-12-14T12:27:16.660" LastActivityDate="2020-12-16T08:02:02.697" Title="Are metals and other elements in every continent?" Tags="|geology|economic-geology|ore|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20572" PostTypeId="1" CreationDate="2020-12-14T07:15:40.543" Score="1" ViewCount="92" Body="&lt;p&gt;Is there any solution to deal with the overpopulation of our species at the same time protect the natural environment of ours? (other than finding a inhabitable planet?)&lt;/p&gt;&#xA;" OwnerUserId="17581" LastActivityDate="2020-12-14T22:13:20.537" Title="Solution for the coexistence of overpopulated human species with nature" Tags="|climate|earth-history|environmental-protection|" AnswerCount="2" CommentCount="1" ClosedDate="2020-12-15T10:12:15.537" ContentLicense="CC BY-SA 4.0" />
  <row Id="20573" PostTypeId="2" ParentId="20565" CreationDate="2020-12-14T07:53:49.067" Score="2" Body="&lt;p&gt;An answer I got on Reddit which seems to make sense is that fronts are usually accompanied by a pressure change which locally reinforces the &amp;quot;normal&amp;quot; &lt;a href=&quot;https://en.wikipedia.org/wiki/Geostrophic_wind&quot; rel=&quot;nofollow noreferrer&quot;&gt;geostrophic wind&lt;/a&gt; which changes the wind direction.&lt;/p&gt;&#xA;&lt;p&gt;If anyone has a more in depth answer I'd love to hear it.&lt;/p&gt;&#xA;" OwnerUserId="21485" LastActivityDate="2020-12-14T07:53:49.067" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20574" PostTypeId="2" ParentId="20572" CreationDate="2020-12-14T08:18:36.170" Score="2" Body="&lt;p&gt;Measures to control human population that have been tried so far have been unpalatable and very unpopular. Everyone want's their own &amp;quot;tribe&amp;quot; to survive.&lt;/p&gt;&#xA;&lt;p&gt;Wars and other significant conflicts caused millions of deaths &amp;amp; the world is still in a precarious situation. &lt;a href=&quot;https://www.positivenegativeeffects.com/world-war-2&quot; rel=&quot;nofollow noreferrer&quot;&gt;World War 2&lt;/a&gt; resulted in the &lt;a href=&quot;https://www.thebalance.com/world-war-ii-economic-impact-4570917&quot; rel=&quot;nofollow noreferrer&quot;&gt;death&lt;/a&gt; of 75 million people. It had a particularly devastating effect on the &lt;a href=&quot;https://en.wikipedia.org/wiki/World_War_II_casualties_of_the_Soviet_Union&quot; rel=&quot;nofollow noreferrer&quot;&gt;population&lt;/a&gt; of &lt;a href=&quot;https://web.williams.edu/Economics/faculty/brainerd-rfwomen.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Russia&lt;/a&gt; and its economy has suffered since. Deaths resulting from &lt;a href=&quot;https://www.warhistoryonline.com/world-war-ii/10-facts-stalins-great-purge.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stalin's purges&lt;/a&gt; and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Holodomor&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ukraine Famine&lt;/a&gt; added to the devastating result.&lt;/p&gt;&#xA;&lt;p&gt;During the 1970s, the &lt;a href=&quot;https://en.wikipedia.org/wiki/The_Emergency_(India)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Emergency in India&lt;/a&gt;, lead to nearly 11 million people being sterilized, mostly forcibly sterilized. A 1970 law lead to the &lt;a href=&quot;https://time.com/5737080/native-american-sterilization-history/&quot; rel=&quot;nofollow noreferrer&quot;&gt;mass sterilization of native American women&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;In 1980, China introduced its &lt;a href=&quot;https://en.wikipedia.org/wiki/One-child_policy&quot; rel=&quot;nofollow noreferrer&quot;&gt;One Child policy&lt;/a&gt;, the results of which are &lt;a href=&quot;https://theconversation.com/africa/topics/one-child-policy-4536&quot; rel=&quot;nofollow noreferrer&quot;&gt;still being felt&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-12-14T08:18:36.170" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20575" PostTypeId="2" ParentId="20570" CreationDate="2020-12-14T08:41:41.163" Score="25" Body="&lt;p&gt;Metals occur on every continent . The issue is whether or not they occur in sufficiently large deposits for them to be mined economically.&lt;/p&gt;&#xA;&lt;p&gt;The difference between a mineral deposit and an ore body is economics: can it be mined for a profit?&lt;/p&gt;&#xA;&lt;p&gt;One of the issues with mineral resources is that once they've been mined, they're gone.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Mining_in_Cornwall_and_Devon&quot; rel=&quot;noreferrer&quot;&gt;Cornwall and Devon&lt;/a&gt;, in the UK, were once a significant producer of tin and copper.&lt;/p&gt;&#xA;&lt;p&gt;Spain is major source of metals in Europe. Some of its mines were started by the ancient Romans. &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_mines_in_Poland&quot; rel=&quot;noreferrer&quot;&gt;Poland&lt;/a&gt; too, has a active mining industry, as does &lt;a href=&quot;https://en.wikipedia.org/wiki/Mining_in_Sweden&quot; rel=&quot;noreferrer&quot;&gt;Sweden&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Chile and Peru are major sources of copper, but &lt;a href=&quot;https://www.thoughtco.com/the-world-s-20-largest-copper-mines-2014-2339745&quot; rel=&quot;noreferrer&quot;&gt;copper&lt;/a&gt; is also mined in the US, Zambia, Australia and Russia.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Mineral_industry_of_Africa&quot; rel=&quot;noreferrer&quot;&gt;Africa&lt;/a&gt; has a well established mining industry that mines many metals: gold, copper, iron, lead, zinc and platinum.&lt;/p&gt;&#xA;&lt;p&gt;Metal mining in &lt;a href=&quot;https://en.wikipedia.org/wiki/Mining_in_Australia&quot; rel=&quot;noreferrer&quot;&gt;Australia&lt;/a&gt; and Canada provide both countries with significant sources of export income.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.intechopen.com/books/iron-ores-and-iron-oxide-materials/the-chinese-iron-ore-deposits-and-ore-production&quot; rel=&quot;noreferrer&quot;&gt;China has iron ore deposits&lt;/a&gt; that grade between 25 and 40 percent iron, but it prefers to buy higher grade iron ore, grading 65 to 70 percent iron, from elsewhere, mostly from Brazil, Australia and South Africa, because it is cheaper to produce steel from higher grade ore.&lt;/p&gt;&#xA;&lt;p&gt;However, mineable quantities of some metals, such as lithium, platinum and rare earth metals tend to be concentrated in specific locations.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="13675" LastEditDate="2020-12-16T08:02:02.697" LastActivityDate="2020-12-16T08:02:02.697" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20576" PostTypeId="2" ParentId="20570" CreationDate="2020-12-14T12:27:04.367" Score="16" Body="&lt;p&gt;All stable elements (and the radioactive U and Th) exist everywhere on Earth. They're in the sand underneath your feet, they're in your bones, they're in the dust in the air, they're in the ocean. The question is how much.&lt;/p&gt;&#xA;&lt;p&gt;There are some estimates on the concentration of each element, and there's a nice table that lists all of them in Wikipedia article &lt;a href=&quot;https://en.wikipedia.org/wiki/Abundance_of_elements_in_Earth%27s_crust&quot; rel=&quot;noreferrer&quot;&gt;Abundance of elements in Earth's crust&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;I searched for where copper comes from and it seems that, even though&#xA;a lot of it comes from Chile, it can be found everywhere in smaller&#xA;amounts. Is this true?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Yes, this is very  true. If you look up the table, you can see that estimates for  copper are between 50 and 100 parts per million. This equals to 0.005% to 0.01%. This leads to your next question:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Could I walk out into the woods right now anywhere in the world and&#xA;find copper and iron?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Yes, you will find copper. But assuming it's just an average rock, copper will only be 0.01%. This is very unremarkable and useless. You will probably not even be able to see it or detect it  unless you have  specialised instruments. Other than copper, it will have much more of  many other  elements.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;This leads to the discussion of ore deposits. What is special about places like Chile, where in certain places you can have 1% of copper, instead of 0.01%? This is hundred times more abundant than in the average crust, and there's enough copper in there so its sale value covers for the cost of mining it, and leads to additional profit. The answer is in the exciting field of ore deposit geology, which employs many people in governments, industry, and academia.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-12-14T12:27:04.367" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20577" PostTypeId="1" AcceptedAnswerId="20578" CreationDate="2020-12-14T15:31:50.453" Score="8" ViewCount="1408" Body="&lt;p&gt;I would like to find a formula to approximate RH based on known &lt;em&gt;air temperature&lt;/em&gt; and &lt;em&gt;dew point&lt;/em&gt;. I need the approximation to be valid at least between -20...+40 degrees Celsius. I read the accepted answer on &lt;a href=&quot;https://earthscience.stackexchange.com/questions/16570/how-to-calculate-relative-humidity-from-temperature-dew-point-and-pressure&quot;&gt;this question&lt;/a&gt;, but unfortunately&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the link for the document where the tabulated values were retrieved from is no longer working&lt;/li&gt;&#xA;&lt;li&gt;using those values yield weird results. I tried it (the RH formula with the constants in the first row of the table) with T = 16.15 and TD (dew point) = -4.45, and it gives 215% RH (could it be &lt;span class=&quot;math-container&quot;&gt;$100^{m*...}$&lt;/span&gt; instead of &lt;span class=&quot;math-container&quot;&gt;$100 *10^{m*...}$&lt;/span&gt;?...)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Any help would be appreciated. Thanks.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Thanks @BarocliniCplusplus for his answer. If anyone reading this needs an implementation in Python to approximate the RH, here is one:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;RH = 100*(math.exp((17.625*TD)/(243.04+TD))/math.exp((17.625*T)/(243.04+T)))&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;where T is the temperature in Celsius, and TD the dew point in Celsius. This approximation is derived from the &amp;quot;Conclusions&amp;quot; section of &lt;a href=&quot;https://journals.ametsoc.org/view/journals/apme/35/4/1520-0450_1996_035_0601_imfaos_2_0_co_2.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; and is suggested to have relative error of 0.384% or less when used between -40°C and 50°C.&lt;/p&gt;&#xA;" OwnerUserId="21492" LastEditorUserId="21492" LastEditDate="2021-10-16T09:46:17.747" LastActivityDate="2021-10-16T09:46:17.747" Title="Relative Humidity approximation from Dew Point and Temperature" Tags="|meteorology|atmosphere|temperature|humidity|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20578" PostTypeId="2" ParentId="20577" CreationDate="2020-12-14T16:54:38.980" Score="8" Body="&lt;p&gt;The equation for relative humidity is &lt;span class=&quot;math-container&quot;&gt;$$RH=100\times \frac{e}{e_s(T)}=100\times \frac{e_s(T_d)}{e_s(T)} \tag{1}$$&lt;/span&gt;&#xA;Where &lt;span class=&quot;math-container&quot;&gt;$T_d$&lt;/span&gt; is the dewpoint temperature and &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; is the temperature, &lt;span class=&quot;math-container&quot;&gt;$e$&lt;/span&gt; is the water vapor pressure, and &lt;span class=&quot;math-container&quot;&gt;$e_s$&lt;/span&gt; is the saturation vapor pressure, which is also known as the &lt;a href=&quot;https://glossary.ametsoc.org/wiki/Clausius-clapeyron_equation&quot; rel=&quot;noreferrer&quot;&gt;Clausius Clapeyeron equation.&lt;/a&gt; While the previous link has a decent definition and equation, my preferred equation (particularly because it is derivable) is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Clausius%E2%80%93Clapeyron_relation#Ideal_gas_approximation_at_low_temperatures&quot; rel=&quot;noreferrer&quot;&gt;low temperature approximation&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$e_s(T)= e_s(273 \mathrm{K})\exp\left[\frac{L_v}{R_v}\left(273.15^{-1}-T^{-2}\right)\right] \tag{2}$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; is the temperature or dewpoint temperature &lt;strong&gt;in Kelvin&lt;/strong&gt;, &lt;span class=&quot;math-container&quot;&gt;$L_v$&lt;/span&gt; is the &lt;a href=&quot;https://glossary.ametsoc.org/wiki/Latent_heat&quot; rel=&quot;noreferrer&quot;&gt;latent heat of vaporization&lt;/a&gt;,&lt;span class=&quot;math-container&quot;&gt;$e_s(273 \mathrm{K})=6.11 hPa$&lt;/span&gt;, and &lt;span class=&quot;math-container&quot;&gt;$R_v$&lt;/span&gt; is the &lt;a href=&quot;https://glossary.ametsoc.org/wiki/Gas_constant&quot; rel=&quot;noreferrer&quot;&gt;specific gas constant for water vapor&lt;/a&gt;. Note that &lt;span class=&quot;math-container&quot;&gt;$(2)$&lt;/span&gt; is for liquid water. You may be able to replace &lt;span class=&quot;math-container&quot;&gt;$L_v$&lt;/span&gt; for &lt;span class=&quot;math-container&quot;&gt;$L_s$&lt;/span&gt; for sublimation/deposition. Also note, that this is the &amp;quot;pure&amp;quot; form of the relative humidity equation. &lt;a href=&quot;https://en.wikipedia.org/wiki/Raoult%27s_law&quot; rel=&quot;noreferrer&quot;&gt;The presence of solutes&lt;/a&gt; (&lt;a href=&quot;https://en.wikipedia.org/wiki/Cloud_condensation_nuclei&quot; rel=&quot;noreferrer&quot;&gt;Cloud condensation nuclei&lt;/a&gt;) may lower the saturation vapor pressure, increasing the actual relative humidity. I'll let combining &lt;span class=&quot;math-container&quot;&gt;$(1)$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$(2)$&lt;/span&gt; be an exercise left for the reader.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2020-12-14T16:54:38.980" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20579" PostTypeId="2" ParentId="20572" CreationDate="2020-12-14T22:13:20.537" Score="3" Body="&lt;p&gt;It's important to understand that this problem is a bit more nuanced.&lt;/p&gt;&#xA;&lt;p&gt;Population growth in every species is exponential (as much as exponential growth can exist, in reality almost nothing is proven to grow infinitely, therefore at some point stops growing exponentially).&lt;/p&gt;&#xA;&lt;p&gt;Check out this for a description of carrying capacity. In a lot of ways it shows that human population growth is not much different than any other species... but we do it on such a grand scale, and that is something to consider. &lt;a href=&quot;https://en.wikipedia.org/wiki/Carrying_capacity#:%7E:text=The%20carrying%20capacity%20of%20an,water%2C%20and%20other%20resources%20available&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Carrying_capacity#:~:text=The%20carrying%20capacity%20of%20an,water%2C%20and%20other%20resources%20available&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The biggest problem in the future may not be our exponential growth, but our increase in carrying capacity for our specific environment (which for humans is the entire Earth). The most significant cause of this is the Green Revolution (agricultural improvements, not environment).&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Green_Revolution&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Green_Revolution&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;We certainly don't want to see that carrying capacity drop.&lt;/p&gt;&#xA;" OwnerUserId="4461" LastActivityDate="2020-12-14T22:13:20.537" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20582" PostTypeId="2" ParentId="20570" CreationDate="2020-12-15T21:28:13.343" Score="4" Body="&lt;p&gt;Part of the problem is in the question itself. In the title, you ask about &amp;quot;in every continent&amp;quot; while in the text, you imply that you are talking about smaller areas.&lt;/p&gt;&#xA;&lt;p&gt;One premise we can safely assume is that most elements are distributed &lt;em&gt;unevenly&lt;/em&gt;. That is a far more relaxed question than you are asking, though.&lt;/p&gt;&#xA;&lt;p&gt;For an example, look at hydrogen.&lt;/p&gt;&#xA;&lt;p&gt;You will find a lot more hydrogen in a cubic meter of ocean water than in the same amount of Sahara sand away from the Nile river (but not zero - there still is water in even the driest parts of the Sahara, and hydrogen could also be part of some of other chemical compounds found there).&lt;/p&gt;&#xA;&lt;p&gt;But there are lakes and waterfalls on the same continent as the Sahara desert, so the &lt;em&gt;continent&lt;/em&gt; of Africa contains a lot more hydrogen than the Sahara desert.&lt;/p&gt;&#xA;&lt;p&gt;You can apply similar reasoning to most elements.&lt;/p&gt;&#xA;&lt;p&gt;So if you are truly asking about continents, the answer is likely: &amp;quot;pretty much every element will be found &lt;em&gt;somewhere&lt;/em&gt; on each continent&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;As you get more granular, it becomes more difficult to answer. It is &lt;em&gt;theoretically&lt;/em&gt; conceivable that there might be one cubic meter of earth surface that is missing some elements. In the spirit of your question, I don't think we should go more granular than that. And I'm also only looking at &amp;quot;stuff&amp;quot; near or above the surface of the earth, say, within range of mining or drilling.&lt;/p&gt;&#xA;&lt;p&gt;The next part of the question is, which elements are candidates for missing completely?&lt;/p&gt;&#xA;&lt;p&gt;If an element (or a compound containing it) is water-soluble, odds are that after 4 billion years, it has distributed through nearly all water (with the possible exception of rain water, which has been distilled and only picked up materials suspended in the atmosphere). And since water is pretty much everywhere on earth, anything that is water soluble probably found its way, in minute quantities, in every crevice.&lt;/p&gt;&#xA;&lt;p&gt;The best candidates for insolubility would probably be noble gases and certain metals. But even those are, to a small extent, soluble. I am not aware of any element that is absolutely insoluble in water in any form.&lt;/p&gt;&#xA;&lt;p&gt;So the answer to your question is likely: while it is theoretically possible that there are a few spots (of more than one cubic meter) that do not contain &lt;em&gt;any&lt;/em&gt; of a particular non-radioactive element, it is exceedingly unlikely. Materials on earth just have been too thoroughly mixed.&lt;/p&gt;&#xA;" OwnerUserId="4868" LastActivityDate="2020-12-15T21:28:13.343" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20583" PostTypeId="1" CreationDate="2020-12-16T12:38:01.423" Score="5" ViewCount="200" Body="&lt;p&gt;I decided to remove the tiles in my front courtyard and turn it into a garden of succulents.  After removing a couple of rows of tiles then digging into the soil, I started seeing a strange thick white clay like substance like melted marshmallows. I figured it was obviously clay.  But the deeper I dug, I started to see lots of very vivid colours: very dark red, almost purple, yellows, oranges greys, pinks, blood reds + some dark green. I know sandstones have all sorts of colours due to its make-up of quartz etc - but this was very different.&lt;/p&gt;&#xA;&lt;p&gt;I started to think there was some sort of large animal buried there as that's what it looked like especially with all the reds and pinks and the white substance which there was loads of.&lt;/p&gt;&#xA;&lt;p&gt;I kept seeing long stringy &amp;quot;fibres&amp;quot; thinking it was from a tarpaulin or plastic bag.  BUT.. no.  then I thought it was very fine roots from old plants. NO. there also appears to be 100s if not 1000s of tiny microscopic &amp;quot;white worm&amp;quot; things.&lt;/p&gt;&#xA;&lt;p&gt;What could do this to sandstones or any rock? Turning big sandstones into a very thick stretchy heavy substance which is almost impossible to get off your shovel or gloves or any tool? And there's an enormous amount of this.&lt;/p&gt;&#xA;&lt;p&gt;There's also a large number of tiny black things embedded into the gooey sandstone.&lt;/p&gt;&#xA;&lt;p&gt;I am very concerned about what's happening.  I bought my place in June 2019. Moved in December 2019.  So been here just on a year.&lt;/p&gt;&#xA;&lt;p&gt;I live very close to the city of Sydney. I don't think its the Rock Eating Worm/Shipworm- but I don't know.&lt;/p&gt;&#xA;&lt;p&gt;Any help is greatly appreciated.&lt;/p&gt;&#xA;&lt;p&gt;Thank You&lt;/p&gt;&#xA;&lt;p&gt;Miss Fifi Jones&lt;/p&gt;&#xA;&lt;p&gt;***Shame you can't add a video.  that shows it all best.&lt;/p&gt;&#xA;&lt;p&gt;Sandstone now marshmallow diff colours white soft + gooey:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ALMwS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ALMwS.jpg&quot; alt=&quot;1&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/khPyh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/khPyh.jpg&quot; alt=&quot;2&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fXOAg.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fXOAg.jpg&quot; alt=&quot;3&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/s0vUk.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/s0vUk.jpg&quot; alt=&quot;4&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qeudu.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qeudu.jpg&quot; alt=&quot;5&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6SOCm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6SOCm.jpg&quot; alt=&quot;6&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/M1kr9.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/M1kr9.jpg&quot; alt=&quot;7&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21504" LastEditorUserId="6298" LastEditDate="2020-12-22T10:27:03.147" LastActivityDate="2020-12-22T10:27:03.147" Title="What's eating this sandstone" Tags="|rocks|" AnswerCount="0" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="20584" PostTypeId="2" ParentId="20520" CreationDate="2020-12-16T16:05:18.147" Score="0" Body="&lt;p&gt;Geological maps are the interpretation by a number of geologists and are generally the synthesis of extensive field work. The only place with the real evidence is the field (including geophysical work and drillholes, if available obviously). In many countries geological maps are accompanied with a guide discussing certain interpretations, especially regarding faults, which are quite often up for discussion. Maybe you can find the author of the map and ask them if such a guide is available, or even directly ask on what base the fault was drawn? I think you'd find many geologists willing to discuss their interpretation.&lt;/p&gt;&#xA;&lt;p&gt;Other indications (&amp;quot;evidence&amp;quot; is a bit strong) for thrust faults can include an unexpected contact between two layers, a sudden change in orientation and/or thickness of the layer(s).&lt;/p&gt;&#xA;&lt;p&gt;If you're really sceptical, try to sketch a small geological profile and see if you can make a different interpretation.&lt;/p&gt;&#xA;" OwnerUserId="21508" LastActivityDate="2020-12-16T16:05:18.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20585" PostTypeId="1" CreationDate="2020-12-16T18:34:48.133" Score="1" ViewCount="27" Body="&lt;p&gt;I'm doing a project in junior year chemistry where I get to choose what I investigate as long as it covers course content. I'm interested in exploring how quantitative (ig. incremental) change in an independent variable of soil would change some dependent variable -- particularly through experimentation.&lt;/p&gt;&#xA;&lt;p&gt;I was thinking of seeing how changes in soil pH affect soil fertility, with specifically focusing on phosphate content to measure soil fertility for simplicity + it's the easiest (i think) to do an experiment over. However I'm not sure if there's correlation between these two variables (which wouldn't look good).&lt;/p&gt;&#xA;&lt;p&gt;Any recommendations for independent/dependent variables with correlation + a useful for real-world application of soil chemistry to look into, where a high school level experiment could produce useful observations, would be super appreciated. That's if you think my original phosphate x pH idea wouldn't make sense.&lt;/p&gt;&#xA;" OwnerUserId="21509" LastActivityDate="2020-12-16T18:34:48.133" Title="Looking for variables to compare against pH of soil" Tags="|soil|soil-science|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="20586" PostTypeId="1" AcceptedAnswerId="20587" CreationDate="2020-12-16T22:04:53.570" Score="3" ViewCount="65" Body="&lt;p&gt;Would climate change result in an increase in seismic activities?&lt;/p&gt;&#xA;&lt;p&gt;I can see two potential forces acting:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Temperature dilation of the Earth's surface.&lt;/li&gt;&#xA;&lt;li&gt;A change in the distribution of water mass, fewer glaciers, stronger precipitation.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Is any of this possible?&lt;/p&gt;&#xA;" OwnerUserId="21510" LastEditorUserId="2470" LastEditDate="2020-12-17T07:05:36.703" LastActivityDate="2020-12-17T08:32:25.963" Title="Would climate change result in an increase in seismic activities?" Tags="|climate-change|seismology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20587" PostTypeId="2" ParentId="20586" CreationDate="2020-12-17T07:34:51.520" Score="4" Body="&lt;p&gt;Dilation of the Earth's surface due to atmospheric temperature changes will be negligible due to the amount of temperature increase.&lt;/p&gt;&#xA;&lt;p&gt;Stronger precipitation will not directly lead to an increase in seismic activity. The force of the raindrops will be too small, even over a prolonged periods of time. If stronger precipitation were to occur, the most likely result will be an increase in &lt;a href=&quot;https://en.wikipedia.org/wiki/Soil_erosion&quot; rel=&quot;nofollow noreferrer&quot;&gt;soil erosion&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Landslide&quot; rel=&quot;nofollow noreferrer&quot;&gt;landslides&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The reduction in glacial mass and the increase in water depth will change ground surface stresses. Where there will be an increase in the depth of water there will an increase in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Overburden_pressure&quot; rel=&quot;nofollow noreferrer&quot;&gt;overburden pressure&lt;/a&gt; produced by the water. This may cause an increase in localized seismic activity in some areas.&lt;/p&gt;&#xA;&lt;p&gt;The loss of glacial mass will lead to &lt;a href=&quot;https://en.wikipedia.org/wiki/Post-glacial_rebound&quot; rel=&quot;nofollow noreferrer&quot;&gt;post-glacial rebound&lt;/a&gt; in affected areas, predominantly: Antarctica, Greenland, Canada, Alaska. As the affected areas adjust to the lack, or reduction, of overbearing (overburden) pressure previously supplied by the glacial ice there will be an increase in seismic activity in those regions.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-12-17T07:34:51.520" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20588" PostTypeId="2" ParentId="20586" CreationDate="2020-12-17T08:20:58.940" Score="2" Body="&lt;p&gt;Water can perhaps change the timing of second order seismic activity, although it's not expected to change the amplitude. Activities like fracking and putting water into stress faults have a greater demonstrable effect.&lt;/p&gt;&#xA;&lt;p&gt;The glass-rubber transition temperature of the rocks is above 1000'C, so the rock itself won't undergo a major change in behavior and rocks accumulate stresses at the same rate due to internal convection of the mantle, and so the seismic activity timing can be a bit different, but it's amplitude won't be noticeably higher, and no studies have radically proven an effect of water on seismic activity amplitudes.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://climate.nasa.gov/news/2926/can-climate-affect-earthquakes-or-are-the-connections-shaky/#:%7E:text=Scientists%20know%20earthquakes%20can%20be,But%20there%27s%20a%20catch&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://climate.nasa.gov/news/2926/can-climate-affect-earthquakes-or-are-the-connections-shaky/#:~:text=Scientists%20know%20earthquakes%20can%20be,But%20there's%20a%20catch&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;About 47 TeraWAtts of energy arrives at the surface from the mantle, and 173,000 TeraWatts comes from the sun.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EiXvx.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EiXvx.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;above image from &lt;a href=&quot;https://www.mpg.de/6348886/W005_Environment-climate_070-077.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.mpg.de/6348886/W005_Environment-climate_070-077.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LvMvs.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LvMvs.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;from wiki.&lt;/p&gt;&#xA;&lt;p&gt;Your question has taught me that Aristotle stated earthquakes can be due to air being released from underground caves.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2020-12-17T08:32:25.963" LastActivityDate="2020-12-17T08:32:25.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20590" PostTypeId="1" CreationDate="2020-12-17T21:27:50.427" Score="3" ViewCount="34" Body="&lt;p&gt;I am interested in which year has the best representation of average weather across a large area, the contiguous USA. This is challenging since what was average in the Midwest might have been unusual in the Southeast at that time. Still I think there is a year that is closest to 'normal' for the largest portion of the USA compared to other years.&lt;/p&gt;&#xA;&lt;p&gt;Am I wrong to think one year could represent an average for such a large area? If needing to pick a year most representative across the contiguous USA, how would one identify the best year, say from 1990-2020? Is there an easy place to lookup this kind of climate information, or what calculations would need to be done?&lt;/p&gt;&#xA;" OwnerUserId="4789" LastActivityDate="2020-12-17T21:27:50.427" Title="Is there an average year of weather across the United States?" Tags="|meteorology|climate|united-states|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20593" PostTypeId="2" ParentId="14514" CreationDate="2020-12-18T22:23:11.410" Score="2" Body="&lt;p&gt;You all got it wrong!&#xA;Coriolis force has nothing to do with the centrifugal force.&lt;/p&gt;&#xA;&lt;p&gt;The main answer to the question why Coriolis doesn't apply in the East-West direction is that East-West direction is not a straight line, so they are already curved themselves.&lt;/p&gt;&#xA;&lt;p&gt;No object on Earth can travel dead East or dead West when shot from a source if there is a constant turn applied to it  The parallels of the Earth are not straight lines, only the equator is.&lt;/p&gt;&#xA;&lt;p&gt;The Coriolis Effect only has to do with geometry and actually doesn't even care about North, South, East or West: it works by the same amount in all directions. You can take a pencil out and see how it works purely geometrically.&lt;/p&gt;&#xA;&lt;p&gt;Also the &amp;quot;vertical&amp;quot; component of the Coriolis effect is there (Eotvos effect), but it is not needed to explain this question nor to explain the formation of depressions as it is so small that it plays no part in this.&lt;/p&gt;&#xA;" OwnerUserId="21528" LastEditorUserId="2470" LastEditDate="2020-12-19T02:20:38.297" LastActivityDate="2020-12-19T02:20:38.297" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20594" PostTypeId="2" ParentId="4346" CreationDate="2020-12-19T20:47:52.833" Score="0" Body="&lt;p&gt;More trees have been planted than ever before with the Arbor Society. Oxygen is the biproduce as plants need carbon dioxide to live(photosynthasis.) Volcanic, platelet fishers and forest fires account for natural carbon dioxide in the atmosphere. Man made fossil fuels are only a small % of carbon dioxide. They do contribute to the % level though.&lt;/p&gt;&#xA;" OwnerUserId="21530" LastActivityDate="2020-12-19T20:47:52.833" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20595" PostTypeId="1" AcceptedAnswerId="20603" CreationDate="2020-12-20T13:27:19.550" Score="2" ViewCount="665" Body="&lt;p&gt;Someone, who does not believe climate change asked me today --&lt;/p&gt;&#xA;&lt;p&gt;How is it possible for us to conclude that the past five years are the hottest five years since record begun, since&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;There are only a limited number of locations where we measure temperature.&lt;/li&gt;&#xA;&lt;li&gt;There is a wide range of difference in temperature even in a small area.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;How would a meteorologist answer these questions?&lt;/p&gt;&#xA;" OwnerUserId="21532" LastActivityDate="2020-12-26T13:58:41.083" Title="What are the evidences that the earth climate is getting warmer?" Tags="|climate-change|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20596" PostTypeId="1" AcceptedAnswerId="20600" CreationDate="2020-12-20T16:31:27.597" Score="4" ViewCount="374" Body="&lt;p&gt;people always talk about global temperature (such as the global temperature goal of 1,5 K) - but how is this value achieved? It seems to me that it clearly depends on where the measuring stations are, how far they are apart and how one weighs them. Has anyone got any paper/report at hand that declares how this is done (at the moment)?&lt;/p&gt;&#xA;&lt;p&gt;Thank you very much!&lt;/p&gt;&#xA;" OwnerUserId="21534" LastActivityDate="2020-12-22T13:41:02.260" Title="How to measure global temperature?" Tags="|meteorology|climate-change|geophysics|temperature|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20598" PostTypeId="1" CreationDate="2020-12-20T23:02:30.797" Score="4" ViewCount="703" Body="&lt;p&gt;(Note: this is from U.S. point of view)&lt;/p&gt;&#xA;&lt;p&gt;I keep hearing how the glaciers &amp;quot;moved South&amp;quot; during the last ice age. But I thought glaciers moved downhill.&lt;/p&gt;&#xA;&lt;p&gt;I can see that the glaciers &lt;em&gt;formed&lt;/em&gt; farther and farther south as the temperature fell. But then they presumably moved downhill, following the landscape beneath them.&lt;/p&gt;&#xA;&lt;p&gt;However: assuming the glaciers were much thicker to the North, then the (hydrostatic?) pressure beneath them would be higher than the Southern glaciers; maybe that pushed everything South.&lt;/p&gt;&#xA;" OwnerUserId="21308" LastActivityDate="2020-12-28T06:37:10.400" Title="Last ice age: did glaciers move South or move downhill?" Tags="|ice-age|ice-sheets|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20599" PostTypeId="2" ParentId="20554" CreationDate="2020-12-21T02:15:02.853" Score="0" Body="&lt;p&gt;Changes in axial tilt on out planet occur but during a very large time-frame.&lt;/p&gt;&#xA;&lt;p&gt;What you are referring to is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cataclysmic_pole_shift_hypothesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pole Shift Hypothesis&lt;/a&gt; and it is very improbable to happen (very wild scenario) in the near and not so near future.&lt;/p&gt;&#xA;&lt;p&gt;But to answer your question, in case of a sudden event of axial tilt, tectonic movement would occur (and not only).&lt;/p&gt;&#xA;&lt;p&gt;It would probably be a most catastrophic event that would include:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;large cracks in Earth's crust&lt;/li&gt;&#xA;&lt;li&gt;tectonic movement that would create:&#xA;&lt;ul&gt;&#xA;&lt;li&gt;vast volcanic eruptions&lt;/li&gt;&#xA;&lt;li&gt;extremely powerful earthquakes&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerDisplayName="user19169" LastEditorDisplayName="user19169" LastEditDate="2020-12-21T02:21:11.380" LastActivityDate="2020-12-21T02:21:11.380" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20600" PostTypeId="2" ParentId="20596" CreationDate="2020-12-21T14:10:13.990" Score="0" Body="&lt;p&gt;Measuring stations are used, but to fill in the gaps that are inherently there. Satellite observations of surface level temperatures are used to smooth out the data (and gather information about the oceans) to create a full look at the global temperature.&lt;/p&gt;&#xA;&lt;p&gt;Then the observed temperatures are compared to averages from recorded history and hot and cold spots are determined. Then finally the temperature deviations are added and subtracted respectively from each other until all deviations have been accounted for and a determination of above or below average is determined.&lt;/p&gt;&#xA;&lt;p&gt;ECMWF uses their Copernicus satellites for this type of research which is documented in &lt;a href=&quot;https://www.ecmwf.int/sites/default/files/elibrary/2014/14665-use-satellite-data-reanalysis.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this presentation&lt;/a&gt;. The data is available through their ERA5 database.&lt;/p&gt;&#xA;" OwnerUserId="13660" LastEditorUserId="13660" LastEditDate="2020-12-22T13:41:02.260" LastActivityDate="2020-12-22T13:41:02.260" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20601" PostTypeId="1" AcceptedAnswerId="20633" CreationDate="2020-12-19T05:56:33.483" Score="9" ViewCount="392" Body="&lt;p&gt;Why is the density of particles in Earth's atmosphere above surface-level so much less than ground and below? Why, instead, isn't Earth simply a ball of swirling gasses / liquids, which become progressively denser as you approach the core (since gravitational pull is stronger closer to the core)?&lt;/p&gt;&#xA;" OwnerUserId="21581" OwnerDisplayName="Nikhil Kokra" LastActivityDate="2021-01-13T14:14:38.833" Title="Why is Earth's density gradient a step-function, rather than smooth?" Tags="|atmosphere|geology|" AnswerCount="4" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20602" PostTypeId="2" ParentId="20601" CreationDate="2020-12-21T16:38:59.160" Score="1" Body="&lt;p&gt;Atoms also interact electromagnetically, and this changes their behaviour.  In particular, iron will form metallic bonds, while silcon will bond covalently with oxygen forming massive solid structures.  On the other hand, Nitrogen will bond to itself forming small molecules that don't link to other molecules. As a result, the iron and silicates will form a solid with much higher density than Nitrogen.  The iron and silicates will then fall together with the nitrogen floating above, and there will be a sharp step change in density as you move from the region where there is Nitrogen (and other gases) to the region where there are silicates (and other minerals)&lt;/p&gt;&#xA;&lt;p&gt;If Electromagnetic forces didn't do this there would be only a galaxy-sized blob of Hydrogen and Helium nuclei, as we see with the dark matter halo (which interacts gravitationally but not electromagnetically)&lt;/p&gt;&#xA;&lt;p&gt;It is the electromagnetic interactions that form chemical bonds, and the different types of interaction between different chemical species, that explain why there is a sharp change in density at the boundary between crust and atmosphere, or between ocean and atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;Similar step changes also exist between ocean and crust, and within the Earth, between the mantle and the core.&lt;/p&gt;&#xA;" OwnerUserId="9563" LastActivityDate="2020-12-21T16:38:59.160" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20603" PostTypeId="2" ParentId="20595" CreationDate="2020-12-22T02:09:56.407" Score="4" Body="&lt;p&gt;Besides rising surface air temperatures other indicators of global warming include -&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;ocean surface temperatures rising&lt;/li&gt;&#xA;&lt;li&gt;ocean temperature at varying depths rising&lt;/li&gt;&#xA;&lt;li&gt;global average sea level rising&lt;/li&gt;&#xA;&lt;li&gt;Arctic sea ice extent decreasing&lt;/li&gt;&#xA;&lt;li&gt;Arctic sea ice thickness and average age decreasing&lt;/li&gt;&#xA;&lt;li&gt;Glacier retreat&lt;/li&gt;&#xA;&lt;li&gt;Earlier Spring snow melt&lt;/li&gt;&#xA;&lt;li&gt;Borehole temperatures rising&lt;/li&gt;&#xA;&lt;li&gt;Earlier budding time of various plants&lt;/li&gt;&#xA;&lt;li&gt;Less new record low temperatures&lt;/li&gt;&#xA;&lt;li&gt;More new record high temperatures&lt;/li&gt;&#xA;&lt;li&gt;Greenland losing ice mass&lt;/li&gt;&#xA;&lt;li&gt;Antarctica losing ice mass&lt;/li&gt;&#xA;&lt;li&gt;and etc&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Every possible way we can observe and measure the changes we should expect with global warming shows results consistent with actual global warming.&lt;/p&gt;&#xA;&lt;p&gt;Global Average Temperature as the go to single simple measure is a statistical construct, derived mostly from about 7,000 long running and up to 30,000 current weather stations recording daily minimum and maximums. It is a way to reduce complex change to a single simple number, for convenience. That metric may be a construct but it is constructed to show the extent of change to those recorded temperatures. In one sense it isn't a direct measurement of &amp;quot;something&amp;quot;, yet we can confidently expect this average to rise if the climate system is warming - and not rise if it is not.&lt;/p&gt;&#xA;&lt;p&gt;These weather records allow other kinds of examination besides getting a global average temperature - mapping of regional changes, geographic ones and all the way down to the conditions at individual sites, including their suitability for inclusion in global temperature record calculations. Badly sited ones can be excluded, step temperature changes from changing location or changes to existing location can be adjusted for to achieve better accuracy.&lt;/p&gt;&#xA;&lt;p&gt;These records don't exist in isolation - there is a broad understanding of climate and weather processes that goes with them. They are also supported by satellite data, such as microwave sounding that allow remote estimation of atmospheric temperatures; whilst they tend to show higher response to El Nino Southern Oscillation, the rates of warming are broadly consistent with weather station records.&lt;/p&gt;&#xA;&lt;p&gt;It is a reliable observation that in between nearby weather stations sharing similar geography there are similar weather conditions, including similar maximum and minimum temperatures. Consistently different conditions in the spaces between would be noticed and we cannot expect such differences to be confined only in those between spaces; if there were significant variations in the temperatures and rates of change over time in the spaces between locations &lt;em&gt;it would be happening at those locations as well&lt;/em&gt; and that would show up in the weather station records. What we find in those records is consistent with global warming.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2020-12-22T02:09:56.407" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20606" PostTypeId="1" CreationDate="2020-12-23T09:30:09.077" Score="6" ViewCount="70" Body="&lt;p&gt;I reside in Bangkok where the local press have reported several times these two last months November-December about high levels of smog. A similar phenomenon occurred last year in this period (end of the tropical cold season); both this year and last year, when this smog was very evident I felt colder than in other days of the year.&lt;/p&gt;&#xA;&lt;p&gt;Why does air pollution comes with cold weather in tropical areas?&lt;/p&gt;&#xA;" OwnerUserId="21546" LastActivityDate="2020-12-28T08:29:41.823" Title="Why does air pollution comes with cold weather in tropical areas?" Tags="|air-pollution|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20607" PostTypeId="2" ParentId="20606" CreationDate="2020-12-23T15:01:27.963" Score="0" Body="&lt;p&gt;I do not know about the specifics of Air Quality in Thailand and honestly most of my intuition comes from experience of moderate climates.&lt;/p&gt;&#xA;&lt;p&gt;I would guess that the main reason for increase in frequency of pollution episodes is the slowing down of ground level atmospheric convection due to cooling of the air. This is a natural reason and probably the most important one.&lt;/p&gt;&#xA;&lt;p&gt;However there is also an anthropogenic factor, namely an increase in fuel burning for heating. This definitely applies to Northern India and Central Asia and I would guess might apply to Thailand.&lt;/p&gt;&#xA;" OwnerUserId="2511" LastActivityDate="2020-12-23T15:01:27.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20608" PostTypeId="1" CreationDate="2020-12-23T15:28:26.197" Score="5" ViewCount="166" Body="&lt;p&gt;Where can I find a free Python API that provides historical weather data (temperature, rainfall)? I'd need data of an Italian city, at least with hourly granularity.&lt;/p&gt;&#xA;" OwnerUserId="21548" LastActivityDate="2020-12-23T15:28:26.197" Title="Free historical weather data API" Tags="|meteorology|rainfall|python|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20610" PostTypeId="2" ParentId="20606" CreationDate="2020-12-24T01:23:50.530" Score="2" Body="&lt;p&gt;Crop burning is a major cause.  Crops are burnt Lal across Thailand between December and march and air movements bring large concentrations south to Bangkok.  Even today islands as remote as Koh Phangan are 135 on AQI.  Can't imagine tourism can work with crop burning.&lt;/p&gt;&#xA;" OwnerUserId="21549" LastActivityDate="2020-12-24T01:23:50.530" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20612" PostTypeId="1" CreationDate="2020-12-25T23:02:34.970" Score="2" ViewCount="2194" Body="&lt;p&gt;San Francisco has around 5 months a year of intermittent rain. San Jose, just 50 miles south and nestled between mountains instead of between waters, has perhaps only 1 month of rain. San Francisco also has notably colder winters and summers than San Jose, to a fairly shocking degree.&lt;/p&gt;&#xA;&lt;p&gt;Geographical differences are three, primarily. First of all, San Francisco is further north, and closer to the Pacific Northwest, but only by 50 miles, or 80 kilometers. Second, San Francisco is surrounded by water, with the San Francisco Bay to the east and the Pacific Ocean to the West, while San Jose is isolated from the Pacific by the Santa Cruz mountains. Third, San Francisco has a far higher population density, with more smog and greenhouse gases as a result, which may or may not be a significant contributor to rain (nucleation sites?).&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Why do these two so proximate cities have such different climates?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/z3vao.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/z3vao.jpg&quot; alt=&quot;Topographical map of San Fransisco and San Jose&quot; /&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/1LQx4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1LQx4.png&quot; alt=&quot;Climate comparison between San Francisco and San Jose&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7287" LastEditorUserId="6298" LastEditDate="2021-01-08T23:30:28.400" LastActivityDate="2021-01-14T10:39:42.377" Title="Why is the weather in San Francisco so different from that in San Jose?" Tags="|meteorology|geography|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20615" PostTypeId="2" ParentId="20612" CreationDate="2020-12-26T03:17:46.123" Score="8" Body="&lt;p&gt;San Francisco is more exposed the maritime westerly weather, whereas San Jose is in a &lt;a href=&quot;https://en.wikipedia.org/wiki/Rain_shadow&quot; rel=&quot;noreferrer&quot;&gt;rain shadow&lt;/a&gt; region with a mountain range between it and the Pacific Ocean.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;San Jose, California, and adjacent cities are usually drier than the rest of the San Francisco Bay Area because of the rain shadow cast by the highest part of the Santa Cruz Mountains.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The exposure of &lt;a href=&quot;https://en.wikipedia.org/wiki/San_Francisco_Bay_Area#Geography&quot; rel=&quot;noreferrer&quot;&gt;San Francisco&lt;/a&gt; to westerly maritime weather and being surrounded by water on three sides are significant reasons why it has a milder climate. It's climate is largely influenced by the cold California Current.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Due to the Bay Area's diverse topography, the result of the clashing tectonic plates, the region is home to numerous microclimates that lead to pronounced differences in climate and temperature over short distances.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/San_Jose,_California#Geography&quot; rel=&quot;noreferrer&quot;&gt;San Jose&lt;/a&gt; however is slightly inland and is surround by mountains of three sides, has less rain and an average of 301 sunshine days each year.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2020-12-26T03:17:46.123" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20618" PostTypeId="2" ParentId="20595" CreationDate="2020-12-26T13:58:41.083" Score="1" Body="&lt;p&gt;Since I asked this question, I have been reading this topic. My conclusion is that the method used in estimating global average temperature is very rigorous, and that all challenges to such estimations are very superficial. A good source of information is this website --&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://skepticalscience.com/argument.php?f=taxonomy&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://skepticalscience.com/argument.php?f=taxonomy&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;You can also look at NASA's recent paper on this topic.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://pubs.giss.nasa.gov/abs/le05800h.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://pubs.giss.nasa.gov/abs/le05800h.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here's an FAQ by NOAA about how they global temperature data&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ncdc.noaa.gov/monitoring-references/faq/anomalies.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncdc.noaa.gov/monitoring-references/faq/anomalies.php&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21532" LastActivityDate="2020-12-26T13:58:41.083" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20619" PostTypeId="1" CreationDate="2020-12-26T15:43:27.437" Score="1" ViewCount="227" Body="&lt;p&gt;I came across this review on Amazon. The cold drink was placed on top of the agate stone and the dye bled and left a permanent mark on the table.&lt;/p&gt;&#xA;&lt;p&gt;Why does this happen? Is it because of the condensation as mentioned by the customer? Can regular warm water also cause the same effect?&lt;/p&gt;&#xA;&lt;p&gt;I just want to know why dyes work, and what makes them bleed.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/e6tmj.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/e6tmj.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21557" LastEditorUserId="2470" LastEditDate="2020-12-26T19:43:00.600" LastActivityDate="2021-01-16T21:36:10.197" Title="What causes dye to bleed from an agate stone?" Tags="|mineralogy|rocks|minerals|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20620" PostTypeId="2" ParentId="20598" CreationDate="2020-12-26T21:24:04.597" Score="5" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Did glaciers move South or move downhill?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You are posing this as an either-or question. The answer is &amp;quot;Yes.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;The highest points above sea level in Manitoba, Minnesota, Ontario, Michigan, Wisconsin, Iowa, and Illinois are respectively 832 meters, 701 meters, 693 meters, 603 meters, 595 meters, 509 meters, and 376 meters. Central Canada and the United State's upper midwest are very flat.&lt;/p&gt;&#xA;&lt;p&gt;Even the eastern parts of the US and Canada are relatively flat compared to the huge ~4000 meter thick ice dome centered roughly on Hudson Bay. &lt;strong&gt;Every&lt;/strong&gt; direction was downhill from the peak of this ice dome. The ice flowed to the west to meet ice streams from the Rocky Mountains (and then turn north or south), to the north toward the Arctic Ocean, to the east toward the Atlantic Ocean, and to the south to meet warmer temperatures. The ice at the southern edges was much thinner, but it still was a downhill flow.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2020-12-26T21:24:04.597" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20621" PostTypeId="2" ParentId="13564" CreationDate="2020-12-27T06:02:53.357" Score="2" Body="&lt;p&gt;ANSWER:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$h={\Delta}t/{\Delta}l$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$h=$&lt;/span&gt; height of LCL (unit depends on unit height of lapse rates)&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;${\Delta}t=T-T_d$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;${\Delta}l=l_t-l_d$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; is surface temp (deg)&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$T_d$&lt;/span&gt; is surface dewpoint temp (deg)&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;${\Delta}l=$&lt;/span&gt; difference between lapse rates (deg)&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$l_t=$&lt;/span&gt; dry adiabatic lapse rate of temperature (deg/unit height)&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$l_d=$&lt;/span&gt; lapse rate of the saturation mixing ratio corresponding to the surface dewpoint (deg/unit height)&lt;/p&gt;&#xA;" OwnerUserId="21560" LastEditorUserId="6298" LastEditDate="2020-12-28T17:25:52.917" LastActivityDate="2020-12-28T17:25:52.917" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20623" PostTypeId="1" CreationDate="2020-12-27T12:53:23.987" Score="3" ViewCount="43" Body="&lt;p&gt;I'm working with a dataset of river flow from NOAA and the locations of the measurements are indicated with a comID.&lt;/p&gt;&#xA;&lt;p&gt;From what I gathered these comIDs are rooted from a dataset called NHD, although I have not found any meaningful information or mapping on them.&lt;/p&gt;&#xA;" OwnerUserId="21562" LastActivityDate="2020-12-27T12:53:23.987" Title="How to map a comID to latitude/longitude?" Tags="|hydrology|rivers|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20624" PostTypeId="2" ParentId="20598" CreationDate="2020-12-27T16:10:59.827" Score="2" Body="&lt;p&gt;Glaciers flow downhill and outwards.  Outwards means if you form a glacier on flat (or with a round body, gravitationally equipotential) ground, then its weight will eventually push it outwards in all directions on the ground; to stop this movement in any direction you need an uphill slope to oppose the outward push from the mass of ice.&lt;/p&gt;&#xA;&lt;p&gt;To the extent that glaciers flow outwards those in the Northern Hemisphere also flow southwards (in the Southern Hemisphere it would be northwards) on a hemispherical scale, as this would be outwards from the pole.  But another factor also contributes to the southward/northward advance in the Northern/Southern Hemisphere.  If the glaciers are growing because of overall cooling around the globe (or at least around the hemisphere) then the region in which ice can accumulate over time instead of all melting each spring advances to lower latitudes.  Thus the glacial area grows into lower latitudes as the global or hemispherical climate cools through precipitation as well as through the hemisphere-wide outward flow.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2020-12-27T16:10:59.827" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20625" PostTypeId="2" ParentId="20598" CreationDate="2020-12-28T06:37:10.400" Score="1" Body="&lt;p&gt;I think that it’s a language issue.&lt;/p&gt;&#xA;&lt;p&gt;When people talk about glaciers “moving south”, they don’t mean that any specific glacier literally moved south. They mean that the general area in which glaciers exist used to extend more south than it used to.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2020-12-28T06:37:10.400" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20626" PostTypeId="2" ParentId="20606" CreationDate="2020-12-28T08:20:23.960" Score="0" Body="&lt;p&gt;For many locations this is typical.&lt;br /&gt;&#xA;This is because the coldest weather in most places is typically caused by cold fronts, intrusions of cooler air from more poleward areas during the cool season.&lt;/p&gt;&#xA;&lt;p&gt;If a cold front (which is an area of lower pressure) passes through, then high pressure will build in behind it.  High pressure tends to cause vertical setups called inversions, where air is cooler near than the surface than higher up in the atmosphere, preventing air from rising (see &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9302/why-are-inversion-layers-so-important-in-meteorology/9305#9305&quot;&gt;Why Are Inversion Layers So Important In Meteorology&lt;/a&gt;).  And near high pressures also tends to have lower pressure gradients, which means lower wind speeds.&#xA;Without any ability to rise or disperse outwards, pollution continues to build up until the weather pattern changes.&lt;/p&gt;&#xA;&lt;p&gt;In these cold high pressures lower wind speeds and temperatures (plus the pleasant weather to work in, as well as the fact such cool periods can often be preceded by rain from the frontal passage) also tend to make good days for intentional burning (see &lt;a href=&quot;https://www.auburn.edu/academic/forestry_wildlife/fire/weather_elements.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;this University of Auburn webpage&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;Plus in much of the world the cool season also brings falling debris from &lt;a href=&quot;https://en.wikipedia.org/wiki/Deciduous&quot; rel=&quot;nofollow noreferrer&quot;&gt;deciduous&lt;/a&gt; plants and leftover fields from harvests in the fall meaning it's a time when more people want to burn to clear out unwanted plants.&lt;br /&gt;&#xA;Plus people may burn to keep warm.&lt;/p&gt;&#xA;&lt;p&gt;So cool periods bring more benefits to burning, good conditions to do so, and weather conditions that cause the resulting pollution to build up.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;The question is: does Bangkok see such cold fronts ever?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;My familiarity is really only with weather patterns nearer the United States.  From that area, I might have guessed no, because the amount of fronts per year decreases as you get into areas like south Florida and parts of central America, which are at greater latitude than Bangkok.  But articles like &lt;a href=&quot;https://www.thaipbsworld.com/cold-weather-has-arrived-with-temperatures-set-to-fall-further-in-coming-days/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cold weather has arrived with temperatures set to fall further in coming days&lt;/a&gt; and &lt;a href=&quot;https://www.thestar.com.my/news/nation/2019/12/16/chilly-mornings-to-continue-as-north-east-monsoon-brings-a-cold-front-says-met-dept&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chilly mornings to continue as north-east monsoon brings a cold front, says Met dept&lt;/a&gt; suggest it's a possibility.  It depends how properly the term cold front is being used in such articles, and what the exact meteorological circumstances are in them.&lt;/p&gt;&#xA;&lt;p&gt;But perhaps the Himalayas\monsoon pattern indeed work together to allow cold air intrusions further south in some areas.  Someone more experienced with Malay\south Asian geography would need to give a more definitive word on this to have confidence.  But it appears, at the very least, cool enough conditions may occur to encourage burning and develop temperature inversions, which would lead to the same stagnant air much of the world sees when under high pressure.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2020-12-28T08:29:41.823" LastActivityDate="2020-12-28T08:29:41.823" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20627" PostTypeId="1" CreationDate="2020-12-28T09:28:18.443" Score="1" ViewCount="78" Body="&lt;p&gt;Mark Shepard in his book &amp;quot;Restoration Agriculture&amp;quot; proclaims&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;[...] small-scale backyard gardening which has shown in study after study to produce more food per acre than broadscale grain farming.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Unfortunately, he doesn't cite any studies or goes into more detail. Is the main point here that grain farming is particularly low on biomass production, or is there a reason why backyard gardening can in generally have higher yields than industrial farming? References would be very welcome!&lt;/p&gt;&#xA;" OwnerUserId="21567" LastEditorUserId="2470" LastEditDate="2020-12-28T10:12:53.227" LastActivityDate="2021-01-29T08:04:00.370" Title="Can small-scale backyard gardening produce more food per acre than broadscale [grain] farming?" Tags="|agriculture|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20628" PostTypeId="1" CreationDate="2020-12-28T16:42:36.850" Score="5" ViewCount="303" Body="&lt;p&gt;Numerous sources repeat that, apart from slowing down the rotation of the globe, the Three Gorges Dam caused the geographic pole to shift by 2 cm. For example:    &lt;a href=&quot;https://blog.prv-engineering.co.uk/engineering-three-gorges-dam/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://blog.prv-engineering.co.uk/engineering-three-gorges-dam/&lt;/a&gt;&#xA;&amp;quot;The secret behind this phenomenon is called inertia and occurs as a result of Newton’s First Law Of Motion. According to NASA scientist, a shift in mass that size does affect the Earth. Raising 42 billion tons of water 180 meters above sea level increases the Earth’s moment of inertia which slows its rotation. It increases the length of a day by 0.06 microseconds while &lt;strong&gt;shifting the pole position by about 2 cm (0.8 inch)&lt;/strong&gt;.&#xA;I'm curious, how did they calculated above mentioned &amp;quot;2cm&amp;quot;?,&lt;/p&gt;&#xA;" OwnerUserId="21561" LastEditorUserId="6129" LastEditDate="2021-01-24T18:52:11.287" LastActivityDate="2021-01-24T18:52:11.287" Title="Did the Three Gorges Dam shift the North Pole by 2 cm?" Tags="|geophysics|water|earth-rotation|dams|" AnswerCount="0" CommentCount="4" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20630" PostTypeId="1" AcceptedAnswerId="20637" CreationDate="2020-12-28T18:59:33.113" Score="1" ViewCount="69" Body="&lt;p&gt;&lt;strong&gt;Link to the original image:&lt;/strong&gt; &lt;a href=&quot;https://postimg.cc/v4bRqxxR&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://postimg.cc/v4bRqxxR&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I believe this image represents two folds which are overturned and plunging. I would like to analyse these folds on a stereonet, but I am unsure how to split the data.&lt;/p&gt;&#xA;&lt;p&gt;I have annotated the image (link below) to show my thoughts on splitting the data into domains. What I am finding confusing is the relation of the data in the &amp;quot;northern domain&amp;quot; to the &amp;quot;southern domain&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Link to annotated image&lt;/strong&gt;: &lt;a href=&quot;https://postimg.cc/Wtc7JBD3&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://postimg.cc/Wtc7JBD3&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Any advise on how to split the data into domains would be helpful and reassuring in my understanding.&lt;/p&gt;&#xA;" OwnerUserId="21432" LastEditorUserId="21432" LastEditDate="2020-12-28T19:06:28.263" LastActivityDate="2020-12-31T01:05:45.760" Title="What is the best way to split strike and dip data on the image provided into &quot;domains&quot; in order to interpret folding on a stereonet?" Tags="|geology|mapping|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20632" PostTypeId="1" AcceptedAnswerId="20635" CreationDate="2020-12-29T17:33:25.877" Score="6" ViewCount="116" Body="&lt;p&gt;I am new to having a PWS (Personal Weather Station). I have not found any answers explaining why this sometimes occurs aside from explanations given factors that were not variables in my case (winds, cloud cover etc). While I had a minor gust (&amp;lt; 1 mph), no change in direction from what it's been all week (directly north). No change in cloud cover, fog, mist etc. Steady barometric pressure rise (overall slight) all night at 30.12 In to 30.26. Every once in a while I see a massive spike in temperature like this with no easily discernable factors and would like to understand why. Furthermore, I checked 5 other weather stations in the valley floor. It looks identical/exact same affects in a 30 mile range. However, as soon as we rise below the valley floor maybe 500 - 1000 ft, we see a steady decrease all night with a slight flattening during this time, but no increase.&lt;/p&gt;&#xA;&lt;p&gt;Details of my location:&#xA;Northwest Montana, mountain surround valley, river bottom, low/lowest point in the valley 1/2 mile from river edge. Station is 6ft above ground, clear from any buildings, trees, structures by at least 200ft in all directions.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pUsqK.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pUsqK.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21572" LastEditorUserId="21572" LastEditDate="2020-12-29T18:46:12.083" LastActivityDate="2020-12-30T06:31:01.387" Title="What factor(s) could cause this sort of temperature increase, mid-night/early morning?" Tags="|meteorology|temperature|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20633" PostTypeId="2" ParentId="20601" CreationDate="2020-12-29T22:53:52.300" Score="13" Body="&lt;p&gt;Roughly put, it's the same thing that makes a density step function when you try to combine oil and water:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/I4hXJ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;a href=&quot;https://www.thoughtco.com/why-oil-and-water-dont-mix-609193&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The components do not mix with or dissolve into each other, so gravity makes the denser material -- water -- settle to the bottom.  The density as a function of height jumps up from the oil density to the water density when you go below the interface.&lt;/p&gt;&#xA;&lt;p&gt;In the case of Earth, there are several progressively denser phases that do not mix.  The biggest step in the density gradient is when the rock phases (olivine, spinel, perovskites, and ferropericlase which is not shown in the illustration below) give way to the much denser core.  In the illustration below, this boundary is where the bottom part of the rocky mantle, the D&amp;quot; layer, meets the predominantly iron core.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/LPYC8.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;a href=&quot;http://www.spring8.or.jp/en/news_publications/publications/scientific_results/earth_science/topic21&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;One major difference between the interior of Earth and the oil-water combination in the first picture is that much of Earth's interior is solid, so it takes a lot of heat and pressure -- both generated by gravity -- to make the materials yield and flow to their equilibrium positions.  The same is true of other predominantly solid celestial bodies, so only relatively large and massive ones have enough gravitational power to enable separation of different density phases.  Planetary scientists call this process &lt;strong&gt;differentiation&lt;/strong&gt;.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2021-01-11T21:16:53.230" LastActivityDate="2021-01-11T21:16:53.230" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20635" PostTypeId="2" ParentId="20632" CreationDate="2020-12-30T06:23:27.317" Score="4" Body="&lt;p&gt;Temperature swings opposite from those expected by the diurnal radiation pattern (warming during the day, cooling at night) are typically due to air coming in from other locations.  Synoptic (large-scale) fronts can bring such rapid shifts, but often tend to be more sharp (rather than gradual) and in one direction (as the front passes).  However occasionally there can be interesting oscillations near more stationary fronts, such as this event from Oklahoma in February 2018:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sC0e4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sC0e4.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;More often, smaller nighttime fluctuations have to do with more mesoscale (local) features.  Different regions cool differently, and the pressure differences caused by the resulting differences in density move the air around... two common causes of such shifts can be circulations around oceans or other large water bodies (probably not pertinent to you!) and terrain-induced circulations (probably much more pertinent!).  The ones that are probably most impactful at night are downslope winds, which are caused by more rapid cooling on the mountain than the air around it, and downvalley winds, caused when enough air builds up from downsloping.  This lecture from &lt;a href=&quot;https://climate.evsc.virginia.edu/EVSC1300/PowerPoint/EVSC1300_guest_lecture_2017.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stephan De Wekker&lt;/a&gt; gives some more details on some of these features and other terrain flows.&lt;br /&gt;&#xA;Often slight shifts in larger-scale wind direction and the varying temperatures over different degrees of mountains and valleys can lead to quite a complicated set of rises and falls in temperature through the night.&lt;/p&gt;&#xA;&lt;p&gt;It's also not impossible that are some issues with your station, I was initially concerned with a few things:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The winds in particular seemed odd -- due north the entire time is always suspicious, and less than 1 mph for an entire night and early morning, while certainly not impossible, makes it a bit more questionable as to whether significant temperature advection could occur.&lt;/li&gt;&#xA;&lt;li&gt;Plus it's also rare to see temperature and dewpoint changing almost 100% exactly in step over long periods of changes -- moisture tends to be slower to alter except around sharper fronts (and on nights when the temperature nudges lower while the air is saturated [&lt;span class=&quot;math-container&quot;&gt;$T=T_d$&lt;/span&gt;]).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;But a look at observations across the region for the time period:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tWI86.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tWI86.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;does show perhaps your data isn't impossible.  The meteograms from Libby [KS59] and Missoula [KMSO] below do show very weak/calm winds and fairly similar temperature/dewpoints movement.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MvSqR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MvSqR.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Still, there's no north winds (except when calm, which is a placeholder when there is no wind), and a slight bit more fluctuation between temperature and dewpoint, so it wouldn't hurt to check whether the station is properly observing.&lt;/p&gt;&#xA;&lt;p&gt;I believe typically flows down a local mountain tend to be cooling at night, as the densest air (coldest) collects along the river.  Other features driven by forced air movement can bring warm air to valleys, like &lt;a href=&quot;https://en.wikipedia.org/wiki/Foehn_wind&quot; rel=&quot;nofollow noreferrer&quot;&gt;foehns&lt;/a&gt; and large-scale downsloping, but those tend to bring drier air in.&lt;br /&gt;&#xA;So assuming it's a valid feature, it appears to be something complex.  It can take years of observations to really understand the flows around complex topographic areas.  But I would posit a guess that maybe a slight wind shift gradually pushed the pooled dense valley air away from you far enough to get you into slightly warmer air away from the river valley bottom.  Or maybe winds become enough to mix down warmer air above.  Differences in snowcover/&lt;a href=&quot;https://boston.cbslocal.com/2015/03/25/ask-eric-why-does-humid-air-melt-snow-faster/&quot; rel=&quot;nofollow noreferrer&quot;&gt;melting effects&lt;/a&gt; or clouds/precipitation might also play a part in what you experienced.  But in that part of the world, I'd expect you'll see many more peculiar local temperature fluctuations over your time observing!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2020-12-30T06:31:01.387" LastActivityDate="2020-12-30T06:31:01.387" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20636" PostTypeId="2" ParentId="20627" CreationDate="2020-12-30T07:48:31.497" Score="1" Body="&lt;p&gt;Efficacy of food production per square foot/acre differs from soil quality and rate of regeneration. It's also a case of if you can produce year round. Some permaculture specialists, monitored one case in an article of &amp;quot;Green America&amp;quot; A 500 sq foot garden producing 300 lbs of produce per year. Among other's. Soil nutrient recycling is a key aspect of producing food year round, along with temperature (Green houses).&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Composting&lt;/li&gt;&#xA;&lt;li&gt;Soil/air temp&lt;/li&gt;&#xA;&lt;li&gt;Growth rate of produce involved&#xA;So the answer is &amp;quot;Yes&amp;quot; if dedication is involved.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2020-12-30T07:48:31.497" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20637" PostTypeId="2" ParentId="20630" CreationDate="2020-12-31T01:05:45.760" Score="1" Body="&lt;p&gt;I think you may have more than 2 domain based on satellite image. Maybe you have three limbs of folds (green) and a fault (red). Please consider this interpretation carefully, I don't know where your study area is, what are its geologic units and structures and plutonic intrusions may deform other rocks (sedimentary, metamorphic and vulcanic), which its satelite images will look like your area, specially in old terrain (Archean ones as part of Brazil, Australia, Canada, United States, Russia, Sweden, among others).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/m4RBG.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/m4RBG.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I recommend:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Try to draw the morphostructural lineaments in the topographic raster of your area. You should use the shadow relief to help you in this task. Then, based on its directions, you can have a ideia about the spacial distribution of the domains.&lt;/li&gt;&#xA;&lt;li&gt;The relief texture (I don't know if these are right words) can also be used to define domains. The roughness of the mountain terrain is the highest in your area.&lt;/li&gt;&#xA;&lt;li&gt;The units with similar ages as Paleoproterozoic ones and Neoproterozoic ones define two domains, at least. It can also improve or subdivided your domains.&lt;/li&gt;&#xA;&lt;li&gt;Plot all data of a specific structure* in some stereogram program as &lt;a href=&quot;https://www.rickallmendinger.net/stereonet&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stereonet&lt;/a&gt;, &lt;a href=&quot;http://igc.usp.br/openstereo/download/&quot; rel=&quot;nofollow noreferrer&quot;&gt;OpenStereo&lt;/a&gt; or &lt;a href=&quot;https://www.holcombe.net.au/software/georient.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Georient&lt;/a&gt;. The Georient has an advantage, you can enter the data by clipboard. The similar structures will be plotted nearby. Based on the clustering, you may improve the domain boundaries.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;*Please, do not plot foliation (Sn) and bedding (S0) in the same stereogram. Each structure should be interpretate individually.&lt;/p&gt;&#xA;&lt;p&gt;About stereogram interpretation, you should see the book of Marshak &amp;amp; Mitra (1988) that show excelent description about this.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Marshak, S. &amp;amp; Mitra, G. 1988. Basic Methods of Structural Geology. Enlewwod Cliffs, Prentice Hall&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;However, the best way is observed the relationship between foliations of different order (Sn and Sn+1) and/or foliation and bedding (Sn X S0) in field. This relationship will indicate the &lt;a href=&quot;https://www.see.leeds.ac.uk/structure/folds/describing/vergence/vergence1.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;vergence&lt;/a&gt;. And then, you must proceed to the interpretation of stereogram.&lt;/p&gt;&#xA;&lt;p&gt;I don't think there are easy way to split. You should to do this manually. I commonly import the data to Excel and classify by domains following the dip direction (or strike), location and, more important, vergence.&lt;/p&gt;&#xA;&lt;p&gt;And, please, read about the geology of your area before you start. This help a lot. I hope that I could help you. I have listen what I wrote to you several times from my teachers during my graduation :). Best luck in your studies.&lt;/p&gt;&#xA;" OwnerUserId="21580" LastActivityDate="2020-12-31T01:05:45.760" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20638" PostTypeId="1" CreationDate="2021-01-02T10:00:19.900" Score="7" ViewCount="930" Body="&lt;p&gt;Which part of solar radiation (visible light vs. infrared radiation) plays main part in keeping Earth's surface warm?&lt;/p&gt;&#xA;" OwnerUserId="18490" LastActivityDate="2021-06-08T03:03:30.293" Title="Which part of solar radiation (VIS, NIR) keeps Earth warm?" Tags="|climate-models|climatology|solar-terrestrial-physics|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20639" PostTypeId="1" CreationDate="2021-01-02T16:13:24.380" Score="4" ViewCount="349" Body="&lt;p&gt;More specifically, I would like to know how the rocks in these pictures have formed:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qIrvL.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qIrvL.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/xgTvd.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xgTvd.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/n6Gkp.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/n6Gkp.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;If this is because magma has melted and trapped the other rocks inside, do they have a different melting point then?&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Images are from St. Blaize Trail in Mossel Bay, South Africa&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="21587" LastEditorUserId="21587" LastEditDate="2021-01-04T08:25:28.283" LastActivityDate="2021-01-07T19:06:11.757" Title="How is it possible for rocks to be trapped within another type of rock?" Tags="|rocks|minerals|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20640" PostTypeId="2" ParentId="20638" CreationDate="2021-01-02T17:18:00.570" Score="-4" Body="&lt;p&gt;&lt;strong&gt;Edit&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I asked an AI your question, and got the following response.  I then analyzed / researched / verified it in the following sections.&lt;/p&gt;&#xA;&lt;p&gt;Short answer - Infrared radiation is what heats the Earth the most, followed closely by visible light, though all frequencies do somewhat heat the earth.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;AI generated answer to the question &amp;quot;Which part of solar radiation (visible light vs. infrared radiation) plays main part in keeping Earth's surface warm?&amp;quot;:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The AI correctly responded with high confidence &amp;quot;Infrared Radiation&amp;quot;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;My own human analysis of the AI's response:&lt;/strong&gt;&#xA;This is produced by the Dragon AI in AI Dungeon, which is likely correct because infrared light has more of a heating effect than visible light.  This is correct per the data I researched below as well:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Researched answer:&lt;/strong&gt; &lt;a href=&quot;https://ag.tennessee.edu/solar/Pages/What%20Is%20Solar%20Energy/Sunlight.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://ag.tennessee.edu/solar/Pages/What%20Is%20Solar%20Energy/Sunlight.aspx&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Much of the energy from the Sun arrives on Earth in the form of infrared radiation. Sunlight in space at the top of Earth's atmosphere at a power of 1366 watts/m2 is composed (by total energy) of about 50% infrared light, 40% visible light, and 10% ultraviolet light[1]. At ground level, this decreases to about 1120-1000 watts/m2, and consists of 44% visible light, 3% ultraviolet (with the Sun at the zenith (directly overhead), but less at other angles), and the remainder infrared. Thus, sunlight's composition at ground level, per square meter, with the sun at the zenith, is about 527 watts of infrared radiation, 445 watts of visible light, and 32 watts of ultraviolet radiation. The balance between absorbed and emitted infrared radiation has a critical effect on the Earth's climate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;If anyone can come up with another reference to strengthen this (or if anything contradicts this), please comment.  I was not able to find anything beyond this link online.&lt;/p&gt;&#xA;" OwnerUserId="11017" LastEditorUserId="11017" LastEditDate="2021-01-09T01:31:48.003" LastActivityDate="2021-01-09T01:31:48.003" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20641" PostTypeId="1" CreationDate="2021-01-02T18:17:27.500" Score="4" ViewCount="54" Body="&lt;p&gt;Good Day All,&lt;/p&gt;&#xA;&lt;p&gt;I have quandary that I am unable to find an answer for.&lt;/p&gt;&#xA;&lt;p&gt;I live in Ontario, Canada.  Then home I reside on is directly on a lakefront.  It makes for beautiful views and wonderful times in the summer with the kids.  In the winter time (currently January) it usually makes for wonderful ice skating and Funtime opportunities.&lt;/p&gt;&#xA;&lt;p&gt;Here is my current issue/quandary.&lt;/p&gt;&#xA;&lt;p&gt;The entire lake is frozen.  There are fishing huts setup, snowmobiles and ATV's are zooming by. Up until a week ago all the ice on our shoreline was frozen more than 8&amp;quot; thick.  Now, currently, all the other properties ice is solid... except mine.  It appears that directly in front of our concrete dock/shoreline, we have water in a liquid state.  The neighbours are skating on their rinks on either side of us...&lt;/p&gt;&#xA;&lt;p&gt;Heres some geography for your own musings...  We reside on the Mississipi Lake just west of Ottawa, Ontario.  We've had cold and warm temperatures with some melting and rain in the past two weeks.  Again, that's the whole area, so all the ice went through the same treatment as everywhere else here.  Yet, directly in front of our home, it has thawed and is no longer freezing...&lt;/p&gt;&#xA;" OwnerUserId="21588" LastActivityDate="2021-01-02T18:17:27.500" Title="Water Freezing Quandary" Tags="|hydrology|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20642" PostTypeId="1" AcceptedAnswerId="20697" CreationDate="2021-01-02T21:21:29.010" Score="1" ViewCount="74" Body="&lt;p&gt;Here is a schematic of a cross section which should represent an anticline:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://postimg.cc/4HcmmZ26&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://postimg.cc/4HcmmZ26&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Below sea level, I have inferred what the units might look like with the dashed lines. As I have interpreted this to be an anticline, it was quite straightforward to understand the possible shape, and by working out true thickness I would represent uniform thickness.&lt;/p&gt;&#xA;&lt;p&gt;Here is another example of a cross section which should represent a thrust fault system (I may have added these faults at a strange angle, but hopefully this gets my point across):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://postimg.cc/CRkXJ2Xc&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://postimg.cc/CRkXJ2Xc&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Would I assume these beds are uniformly dipping? How deep should units be represented?&lt;/p&gt;&#xA;" OwnerUserId="21432" LastActivityDate="2021-01-19T00:38:09.973" Title="How do you infer what a cross section might look like below sea level?" Tags="|geology|mapping|education|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20645" PostTypeId="2" ParentId="20639" CreationDate="2021-01-04T06:54:25.293" Score="3" Body="&lt;p&gt;The rock appears to be a sedimentary rock!&#xA;The sub-angular nature of the clasts indicate that the rock is a breccia. Based on the color of the matrix, I would suggest that these clasts are bound by a cherty (a form of SiO2) cement.&lt;/p&gt;&#xA;&lt;p&gt;More about Breccia here:&#xA;&lt;a href=&quot;https://geology.com/rocks/breccia.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://geology.com/rocks/breccia.shtml&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It'd be helpful if you could mention the location of the photograph.&lt;/p&gt;&#xA;&lt;p&gt;Edit:&#xA;Mossel Bay, South Africa contains rocks that are a part of the Buffelskloof Formation containing these breccias, conglomerates and sandstones/quartzites. But the color of the rock is possibly because of the iron-oxide cement and not chert as I previously thought!&lt;/p&gt;&#xA;" OwnerUserId="20826" LastEditorUserId="20826" LastEditDate="2021-01-05T11:45:21.953" LastActivityDate="2021-01-05T11:45:21.953" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20646" PostTypeId="2" ParentId="20639" CreationDate="2021-01-04T11:09:10.727" Score="6" Body="&lt;p&gt;There are three major types of geological formations that contain or are composed of various rocks:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Breccia&quot; rel=&quot;noreferrer&quot;&gt;breccia&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Conglomerate_(geology)&quot; rel=&quot;noreferrer&quot;&gt;conglomerate&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Xenolith&quot; rel=&quot;noreferrer&quot;&gt;xenoliths&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;Breccia&lt;/strong&gt;&#xA;The word breccia comes from the Italian word for rubble. There are various forms of breccia:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;sedimentary&lt;/li&gt;&#xA;&lt;li&gt;tectonic&lt;/li&gt;&#xA;&lt;li&gt;igneous&lt;/li&gt;&#xA;&lt;li&gt;impact&lt;/li&gt;&#xA;&lt;li&gt;hydrothermal&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The clast (rock fragments) within breccia are angular in shape and generally randomly orientated, a opposed to a conglomerate which is composed of rounded fragments.&lt;/p&gt;&#xA;&lt;p&gt;Sedimentary beccia generally formed in ancient stream beds. Igneous breccia forms as a result of rocks being torn away during volcanic eruptions. Impact beccia results from the impact of meteorites. Hydrothermal breccia results from fissure opening up due to seismic or volcanic activity &amp;amp; hydrothermal fluids (hot water) entering the fissure causing the sides of the fissure to collapse inwards.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Conglomerate&lt;/strong&gt;&#xA;Conglomerates contain rounded rocks bound within a sedimentary unit. They form either within ancient stream systems or in marine environments. They can also form as a result of glacial activity.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Xenolith&lt;/strong&gt;&#xA;Xenoliths are fragments of rock contained with igneous rocks. Their spacing with the host rock is much greater than that of beccia or conglomerate - they are more isolated. They generally result from volcanic eruptions.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-01-04T11:09:10.727" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20647" PostTypeId="1" CreationDate="2021-01-04T12:34:48.180" Score="1" ViewCount="36" Body="&lt;p&gt;Can we use radiometric dating techniques on recent skeletons from, say, around the year 2000 and so on and get the same result as the recorded date of death of the owner of the skeleton? If yes (or no), why?&lt;/p&gt;&#xA;" OwnerUserId="21597" LastActivityDate="2021-01-04T12:34:48.180" Title="Dating recent skeletons with radiometric dating techniques" Tags="|fossils|dating|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20648" PostTypeId="2" ParentId="7212" CreationDate="2021-01-05T15:28:24.663" Score="3" Body="&lt;p&gt;The air temperature is 5 degrees. The water temperature is not.  Same reason a bowl of soup or cup of coffee stays hotter than room temperature for some time before it cools down to room temperature.  Take that bowl or cup and expand it to the size of a lake.&lt;/p&gt;&#xA;" OwnerUserId="21607" LastActivityDate="2021-01-05T15:28:24.663" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20649" PostTypeId="1" CreationDate="2021-01-05T23:10:23.093" Score="1" ViewCount="361" Body="&lt;p&gt;I've been to Lagos and it rains a lot sometimes overflooding but it's pretty sunny. I'm aware that it rains a lot too in Miami. Is the climate the same apart from Lagos being near Equator and ITCZ region?&lt;/p&gt;&#xA;" OwnerUserId="21072" LastActivityDate="2021-01-23T01:38:39.577" Title="Is the weather of Miami, Florida and the weather of Lagos, Nigeria the same" Tags="|meteorology|climate|clouds|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20652" PostTypeId="2" ParentId="20242" CreationDate="2021-01-06T04:27:09.810" Score="0" Body="&lt;p&gt;Because, Mars inferior mass to Earth, less gravity means oregeny (mountain building) was easier on Mars. With 1/3 the gravity, rocks aren't weighed down by their own mass. This allowed the massive buildup of huge mountains. Also mountains on Earth were slowly eroded by natural forces, namely freezing water and rain, two factors that don't apply to Mars anymore. Though wind is substantially fast, the air pressure on Mars is so low, wind erosion is far less a problem. Another factor that affects erosion is biological activity........which isn't an issue on Mars for probably billions of years.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-01-06T04:27:09.810" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20653" PostTypeId="2" ParentId="20638" CreationDate="2021-01-06T05:14:55.370" Score="-1" Body="&lt;p&gt;Electromagnetic radiation converts based on frequency and exposure. Visible light and Infrared waves are the predominant energy sources that can penetrate the atmosphere. Higher energy wavelengths (UV and above) do interact but are often bounced by significant portions. Those radiations interact with atmospheric gases; emit infrared waves in the process.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-01-06T05:14:55.370" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20654" PostTypeId="1" CreationDate="2021-01-06T21:29:27.443" Score="3" ViewCount="94" Body="&lt;p&gt;This is regarding the Correction due to 'Curvature of the drop' made by Lord Kelvin to the Clausius-Clapeyron Equation.&lt;/p&gt;&#xA;&lt;p&gt;So, the idea is that, during large scale nucleation of water vapour into cloud droplets, the equilibrium vapour pressure over a droplet of radius r, is given by&#xA;&lt;span class=&quot;math-container&quot;&gt;$$e_s^{\ curved}(r) = e_s(\infty)*e^{\frac{2\sigma}{\rho_w R_vTr}}$$&lt;/span&gt;&#xA;where, T = temperature, &lt;span class=&quot;math-container&quot;&gt;$R_v$&lt;/span&gt; is gas constant for water vapour, &lt;span class=&quot;math-container&quot;&gt;$\rho_w$&lt;/span&gt; is density of drop, &lt;span class=&quot;math-container&quot;&gt;$\sigma$&lt;/span&gt; is Surface tension, and &lt;span class=&quot;math-container&quot;&gt;$e_s(\infty)$&lt;/span&gt; is the equilibrium vapour pressure over a plain surface at temp T.&lt;/p&gt;&#xA;&lt;p&gt;In order to derive this equation, we used the Gibbs Free Energy, and calculated that for this drop formation process, &lt;span class=&quot;math-container&quot;&gt;$\Delta G = - R_v T ln(\frac{e}{e_s}) \rho_w \frac{4}{3} \pi r^3 + \sigma 4 \pi r^2$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now, when &lt;span class=&quot;math-container&quot;&gt;$e&amp;gt;e_s$&lt;/span&gt;, then the graph of &lt;strong&gt;&lt;span class=&quot;math-container&quot;&gt;$\Delta G$&lt;/span&gt;&lt;/strong&gt; vs r, initially increases up to a critical radius R and then decreases as shown:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MTVxb.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MTVxb.png&quot; alt=&quot;The Curve for &lt;span class=&quot;math-container&quot;&gt;$\Delta G$&lt;/span&gt; vs r, S=e/e_s&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Then, to find the equilibrium condition, we said that &lt;em&gt;The drop is in equilibrium with the surrounding when the radius = R, since the slope of &lt;span class=&quot;math-container&quot;&gt;$\Delta G$&lt;/span&gt; wrt r is 0 at r = R&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, I feel that the equilibrium condition arises for the radius r, for which, &lt;span class=&quot;math-container&quot;&gt;$\Delta G$&lt;/span&gt; = 0. This interpretation does affect the final formula much. It just replaces the &amp;quot;2&amp;quot; with a &amp;quot;3&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Q: Which one of these interpretations is correct and why? Why is the other interpretation incorrect?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Kelvin_equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kelvin's Equation&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sjsu.edu/faculty/watkins/Kelvin2.htm#:%7E:text=%3D%20RwT.ln&quot; rel=&quot;nofollow noreferrer&quot;&gt;A sample Derivation&lt;/a&gt; - A similar derivation is seen in the book &amp;quot;Atmospheric Science - by Wallace and Hobbs&amp;quot;&lt;/p&gt;&#xA;" OwnerUserId="20555" LastActivityDate="2021-01-06T21:29:27.443" Title="Equilibrium condition for Kelvin's Vapor Pressure-curvature equation" Tags="|atmosphere|clouds|thermodynamics|cloud-microphysics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20655" PostTypeId="2" ParentId="20639" CreationDate="2021-01-06T22:53:02.877" Score="2" Body="&lt;p&gt;without detailed photographs, I'm in doubt between:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Breccia of tectonic origin, probably due to an old cemented fault. The cement looks to me rich in iron, hence the colour.&lt;/li&gt;&#xA;&lt;li&gt;High energy conglomerate, so the hardened sediments of a mass movement (something like a landslide).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Nevertheless, I believe it's the second option. There are few blocks that seem too big for a tectonic breccia (at this scale), and I can't see any alignment of the blocks, which would be expected. For a conglomerate of high energy, alignment isn't needed. Besides, a cement rich in iron would imply that the rock has been subject to the action of hydrothermal fluids, which would mean that has been affected by two not-so-common processes.&lt;/p&gt;&#xA;&lt;p&gt;So, just with these photos, I think it's a conglomerate.&lt;/p&gt;&#xA;&lt;p&gt;Answering your last sentence, it can happen, but I've never seen it in that volume. Usually are small (and scarce) pieces - xenoliths - amongst the igneous mass.&lt;/p&gt;&#xA;" OwnerUserId="21611" LastEditorUserId="725" LastEditDate="2021-01-07T05:24:26.720" LastActivityDate="2021-01-07T05:24:26.720" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20656" PostTypeId="2" ParentId="20532" CreationDate="2021-01-07T11:03:27.973" Score="2" Body="&lt;p&gt;The UK Government already publishes information on this at the national level, which may be a useful guide for how to proceed at the local government level.&lt;/p&gt;&#xA;&lt;p&gt;The last UK Climate Change Risk Assessment was &lt;a href=&quot;https://www.gov.uk/government/publications/uk-climate-change-risk-assessment-2017&quot; rel=&quot;nofollow noreferrer&quot;&gt;published in 2017&lt;/a&gt; and the next one is &lt;a href=&quot;https://www.ukclimaterisk.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;imminent in mid-2021&lt;/a&gt;.  They follow risk assessment methods set out in things like the &lt;a href=&quot;https://www.gov.uk/government/publications/the-green-book-appraisal-and-evaluation-in-central-governent&quot; rel=&quot;nofollow noreferrer&quot;&gt;HM Treasury Green Book&lt;/a&gt;, which, despite the name, is not about environmental assessment specifically (there are Orange, Aqua and Magenta Books too).  The Green Book&#xA;has a shorter, &lt;a href=&quot;https://www.gov.uk/government/publications/green-book-supplementary-guidance-environment&quot; rel=&quot;nofollow noreferrer&quot;&gt;climate-specific supplement&lt;/a&gt; that may be a good place to start.  In particular, Annex B of the supplement has lots of links to other resources and tools for doing the assessment.&lt;/p&gt;&#xA;&lt;p&gt;There’s also a &lt;a href=&quot;https://www.local.gov.uk/our-support/climate-change/climate-action-council-plans&quot; rel=&quot;nofollow noreferrer&quot;&gt;local government website&lt;/a&gt; that hosts a slightly random selection of plans that various regions have put together over the last few years.&lt;/p&gt;&#xA;&lt;p&gt;This all looks like a daunting amount of paperwork to a scientist like me, so good luck!&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2021-01-07T11:03:27.973" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20657" PostTypeId="2" ParentId="20639" CreationDate="2021-01-07T19:06:11.757" Score="-1" Body="&lt;p&gt;Conglomerate rocks of non sedimentary nature, are debris from other rocks mixed often with fresh lava pouring over it.&#xA;Another facet is that certain minerals have differing melting points, however subtle, cooling at differing time, creating bumpy pieces.&#xA;during various glacial advances, they carried small rocks over different rock strata where sedimentary processes made these amalgamations&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-01-07T19:06:11.757" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20658" PostTypeId="1" CreationDate="2021-01-08T09:13:26.390" Score="4" ViewCount="189" Body="&lt;p&gt;On Wikipedia's page for apatite, the crystal cleavage is listed as [0001] or [0101], which I assume are Miller indices....&lt;/p&gt;&#xA;&lt;p&gt;But how can there be four numbers/digits instead of two, like there usually are?&lt;/p&gt;&#xA;" OwnerUserId="20985" LastActivityDate="2021-01-16T19:39:50.647" Title="How can the 'crystal cleavage' of apatite have a four-digit number?" Tags="|geology|mineralogy|minerals|crystallography|crystals|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20659" PostTypeId="1" CreationDate="2021-01-08T09:55:31.690" Score="2" ViewCount="185" Body="&lt;p&gt;I am only doing gross calculations here, but...&lt;/p&gt;&#xA;&lt;p&gt;If the Earth has warmed by about one degree Celsius in the last century or so, and the thermal expansion coefficient of water is about .0002085, then the (admittedly salty) ocean should have expanded in volume by about .02%, or 1 part in 5000.  Right?&lt;/p&gt;&#xA;&lt;p&gt;Well, the average depth of the ocean is about 10,000 feet, and if the water has (mostly) nowhere to go but up, shouldn't the seas have risen by about 2 feet, not .75 feet?&lt;/p&gt;&#xA;&lt;p&gt;Ummm, I just thought of something...  Has the ocean not warmed as much as the atmosphere?&lt;/p&gt;&#xA;" OwnerUserId="20985" LastActivityDate="2021-01-28T06:20:39.243" Title="Why has the Earth's average sea level risen 'only' by nine inches after one degree C increase in temperature?" Tags="|climate-change|oceanography|water|climatology|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20660" PostTypeId="1" CreationDate="2021-01-08T10:20:28.073" Score="7" ViewCount="161" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;Consumption-based emissions reflect the consumption and lifestyle&#xA;choices of a country’s citizens.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Via this article &lt;a href=&quot;https://ourworldindata.org/consumption-based-co2&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://ourworldindata.org/consumption-based-co2&lt;/a&gt; I see that Belgium's &lt;strong&gt;consumption-based CO&lt;sub&gt;2&lt;/sub&gt; emissions per capita&lt;/strong&gt; in 2018 is still above the level of 1990.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vKCOw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vKCOw.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I wonder why?&lt;/p&gt;&#xA;&lt;p&gt;Why are Belgium, Luxembourg, Switzerland, Austria, Norway still above their CO&lt;sub&gt;2&lt;/sub&gt; consumption levels, while many other neighbouring countries such as the Netherlands, France, Germany, Italy, Denmark, Poland, Sweden, Ireland, ... did manage to get their levels down?&lt;/p&gt;&#xA;&lt;p&gt;Further more, I am wondering how they can correctly estimate the CO&lt;sub&gt;2&lt;/sub&gt; of all consumption? I believe this is not known for all brands/products?&lt;/p&gt;&#xA;&lt;p&gt;P.S.: In 'Sources' we can read:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Consumption-based emissions are national or regional emissions which&#xA;have been adjusted for trade (i.e. territorial/production emissions&#xA;minus emissions embedded in exports, plus emissions embedded in&#xA;imports). If a country's consumption-based emissions are higher than&#xA;its production emissions it is a net importer of carbon dioxide.&lt;/p&gt;&#xA;&lt;p&gt;The underlying source is an updated version of the paper by &amp;quot;Peters et&#xA;al. (2011). Growth in emission transfers via international trade from&#xA;1990 to 2008.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;► (Updated to 2014) Peters, GP, Minx, JC, Weber, CL and Edenhofer, O 2011. Growth in emission transfers via international trade from 1990 to 2008. Proceedings of the National Academy of Sciences 108, 8903-8908: &lt;a href=&quot;https://bg.copernicus.org/articles/9/3247/2012/bg-9-3247-2012.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://bg.copernicus.org/articles/9/3247/2012/bg-9-3247-2012.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This updated data is available in the latest version of&#xA;the Global Carbon Budget.&lt;/p&gt;&#xA;&lt;p&gt;► &lt;a href=&quot;https://www.icos-cp.eu/science-and-impact/global-carbon-budget/2019&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.icos-cp.eu/science-and-impact/global-carbon-budget/2019&lt;/a&gt; via &lt;a href=&quot;https://www.icos-cp.eu/science-and-impact/global-carbon-budget&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.icos-cp.eu/science-and-impact/global-carbon-budget&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Our World in Data has calculated several additional metrics based on&#xA;the following metrics:&lt;/p&gt;&#xA;&lt;p&gt;► Energy consumption data from BP Statistical Review of World Energy: &lt;a href=&quot;https://www.bp.com/en/global/corporate/energy-economics/statistical-review-of-world-energy.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.bp.com/en/global/corporate/energy-economics/statistical-review-of-world-energy.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;► Long-term GDP data from Maddison Project Database: &lt;a href=&quot;https://www.rug.nl/ggdc/historicaldevelopment/maddison/releases/maddison-project-database-2018&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.rug.nl/ggdc/historicaldevelopment/maddison/releases/maddison-project-database-2018&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;► Population data from the UN World Population Prospects and&#xA;Gapminder: &lt;a href=&quot;https://www.gapminder.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.gapminder.org/&lt;/a&gt; &lt;a href=&quot;https://population.un.org/wpp/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://population.un.org/wpp/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7767" LastEditorUserId="2470" LastEditDate="2021-02-13T06:25:10.587" LastActivityDate="2021-07-13T08:07:20.750" Title="Why is Belgium (and Luxembourg, Switzerland, Austria, Norway) still above consumption CO2 levels per capita of 1990? While many others did go down" Tags="|co2|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20661" PostTypeId="2" ParentId="20612" CreationDate="2021-01-08T12:00:16.087" Score="4" Body="&lt;p&gt;I would submit this as a comment rather than an answer, but I don't have enough reputation yet.&lt;/p&gt;&#xA;&lt;p&gt;Could the geography around San Jose make it more susceptible to descending air from further inland? This could give it drier weather than slightly further north, in addition to the rain shadow effect already mentioned by Fred. &lt;a href=&quot;https://en.wikipedia.org/wiki/Diablo_wind&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Diablo_wind&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The more traditional example of this is the Santa Ana winds in southern California: &lt;a href=&quot;https://en.wikipedia.org/wiki/Santa_Ana_winds&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Santa_Ana_winds&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20542" LastEditorUserId="20542" LastEditDate="2021-01-14T10:39:42.377" LastActivityDate="2021-01-14T10:39:42.377" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20664" PostTypeId="2" ParentId="20660" CreationDate="2021-01-09T19:50:30.973" Score="-9" Body="&lt;p&gt;Because Europe's infinite wisdom. Jokes aside,&#xA;Their anti co2 nonsense has revoked utilization of cheap and clean natural gas.&#xA;Instead Europe to satiate it's energy demands now burns wood and trash.&#xA;Before coal became widely available, wood was used not just for heating homes but also for industrial processes; it was the prdominant energy source for humanity. Even if half the land surface of Britain had been covered with woodland we could have made 1.25 million tonnes of bar iron a year (a fraction of current consumption) and nothing else. Even with a much lower population than today's, manufactured goods in the land-based economy were the preserve of the elite. Deep green energy production – decentralised, based on the products of the land – is far more damaging to humanity than nuclear meltdown. If Europe shuts down their nuclear plants it will not be water, wind or sun, but fossil fuel and imported wood chips to run their industrial society.&lt;/p&gt;&#xA;&lt;p&gt;Nuclear's biggest advantage besides the fact it doesn't atmospherically pollute. A kilowatt-hour worth of coal fired electricity produces about 2.07 lbs of CO2 or over a million tons per terawatt-hour. The nuclear plant in my home state produces 14.9 Terawatt-hours per year; preventing over 15 million tons of CO2 per year or over half a billion tons over the last 40 years. The US nuclear industry keeps 830 million tons of CO2 out of the air annually. The other thing is the power density and 24/7 reliability a Nuclear reactor takes up a few acres of land and on it's size produces about 10-20 terawatt-hours per year; a wind farm or solar farm covers hundreds of thousands of acres. Were 7 billion people; were gonna be 9 billion by 2050 and they're moving to cities from the villages, the world is now 50% urban, up from 14% in 1900, it's gonna be 60% urban people by 2030, and 80% urban by 2050 that's 7 BILLION people living in cities and with it a appetite for city living means 24/7 power demand And they cant rely on combustion for heating, cooking, light and transportation they'll need electric power and that's either gonna come from FOSSIL or Nuclear. Your choice. A GRAM of uranium produces 17 times more energy than a ton of wood.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastEditorUserId="21028" LastEditDate="2021-01-10T08:49:50.657" LastActivityDate="2021-01-10T08:49:50.657" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20666" PostTypeId="2" ParentId="20658" CreationDate="2021-01-10T11:11:01.123" Score="7" Body="&lt;p&gt;This is not a four- digit number but four separare numbers called &lt;strong&gt;Bravais-Miller indices&lt;/strong&gt;.  Bravais-Miller indices descrive the orientation of a crystal plane relative to the symmetry axes of a crystal, as described in &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Miller_index&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;.  Put very briefly, a zero index means the plane is parallel to that axis, while nonzero indices encode the relative values of the intercepts on axes to which the plane is not parallel.  These pieces of information about parallel and nonparallel axes, together, specify the orientation of any plane that passes through the lattice points of a crystal.&lt;/p&gt;&#xA;&lt;p&gt;In cubic crystals there are three principal, fourfold axes and thus you render three (not two) numbers for the Bravais-Miller indices of a plane; this is adapted to most other crystal systems.  But, exceptionally for hexagonal and rhombohedral systems, there are four symmetry axes; three of them in the hexagonally packed basal plane and the fourth perpendicular to them along the sixfold or theefold rotational axis.  Thus four indices are commonly used for that case.  The illustration below (&lt;a href=&quot;https://www.researchgate.net/figure/a-Single-crystal-X-ray-diffractometer-results-of-Al-2-O-3-surfaces-with-miller-indices_fig6_303392726&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;) gives some commonly encountered planes in hexagonal crystals.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/eWmyP.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;Putting the first three axes into the same plane means the intercept designations on these axes must be dependent on each other; in fact those three numbers should add up to zero.  Thus &lt;span class=&quot;math-container&quot;&gt;$[1010]$&lt;/span&gt; is not correct; it should be &lt;span class=&quot;math-container&quot;&gt;$[10(-1)0]$&lt;/span&gt; or using the more common notation for a negative index, &lt;span class=&quot;math-container&quot;&gt;$[10\overline10]$&lt;/span&gt;.  As shown in the above illustration, physically this corresponds to the lateral face of a hexagonal prism.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2021-01-16T19:39:50.647" LastActivityDate="2021-01-16T19:39:50.647" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20667" PostTypeId="2" ParentId="17727" CreationDate="2021-01-10T11:56:03.683" Score="3" Body="&lt;p&gt;&lt;strong&gt;The storm and basics:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here is an animation I got from &lt;a href=&quot;https://twitter.com/NOAASatellites/status/903356742104489986&quot; rel=&quot;nofollow noreferrer&quot;&gt;this NOAA Tweet&lt;/a&gt; of the lightning in Harvey hours before landfall:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SaODd.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SaODd.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This &lt;a href=&quot;https://mashable.com/article/harvey-weather-satellite-maps-lightning&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt;, where I found the imagery, offers some basic thoughts, including the key concept that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;As with most hurricanes, you'll notice that the most active area of lightning production is well away from the center of the storm.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This may well explain the reason you experienced more lightning if you are in a location nearer Houston, as it was quite far from the hurricane.  Landfall was about 180 miles SW of Houston, and by the time the storm made it near the Houston metro, it was much weaker; maximum sustained winds around the metro were generally only 25-40 mph (&lt;a href=&quot;https://www.nhc.noaa.gov/data/tcr/AL092017_Harvey.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;see table starting on page 30&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;hr&gt;  &#xA;&lt;p&gt;&lt;strong&gt;Deeper Look At Causes of Lightning in Tropical Cyclones:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I don't think I've come across horizontal wind shear used as an explanation for the reduced lightning in hurricanes, though that doesn't mean it isn't.  But upon more consideration, I really don't think horizontal wind shear in hurricanes is actually particularly extreme.  Certainly there are higher overall wind speeds than many weather features, but the horizontal gradient generally occurs over the scale of 10s of miles (10s of km) or much more in most of the storm.  Whereas in typical summer thunderstorms, there can quite often be like a 50 mph (75 kph) gradient over just a mile (or even km).  I guess the horizontal shear can be quite big right near the outer and especially inner eyewall edge... but these are such small geographic areas to explain the lack of lightning in the large part of a hurricane.  (Looking at figures 3 and 5 from &lt;a href=&quot;https://journals.ametsoc.org/view/journals/atsc/72/11/jas-d-14-0374.1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper looking at Hurricanes Ivan and Dennis&lt;/a&gt;, it looks like the broad horizontal shear only peaks at like 10 m/s over a distance of 5 km, or about 7 mph per mile in Ivan, and less in Dennis.  I don't think that's a big amount really?)&#xA;And you may know that hurricanes tend to have &lt;a href=&quot;https://www.youtube.com/watch?t=19&amp;amp;v=YwyWp5QV5_U&quot; rel=&quot;nofollow noreferrer&quot;&gt;low vertical wind shear&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;So what &lt;strong&gt;is&lt;/strong&gt; the cause of reduced lightning in hurricanes?&lt;/p&gt;&#xA;&lt;p&gt;The paper &lt;a href=&quot;https://journals.ametsoc.org/view/journals/mwre/130/4/1520-0493_2002_130_0769_risalc_2.0.co_2.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reflectivity, Ice Scattering, and Lightning Characteristics of Hurricane Eyewalls and Rainbands. Part I: Quantitative Description by Cecil et al.&lt;/a&gt; from 2002 summarized it as:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Despite extreme horizontal wind speeds, the vertical motions&#xA;encountered in tropical cyclones are typically rather modest&#xA;(Jorgensen et al. 1985; Black et al. 1996), with magnitudes similar to&#xA;those found in ordinary tropical oceanic convection. Convective&#xA;systems over the tropical oceans produce weaker vertical motions than&#xA;their continental counterparts (LeMone and Zipser 1980; Jorgensen and&#xA;LeMone 1989; Lucas et al. 1994; Igau et al. 1999). These vertical&#xA;motions are normally too weak to suspend large ice particles or&#xA;supercooled raindrops above the melting level.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://ffden-2.phys.uaf.edu/211_fall2010.web.dir/Levi_Cowan/lightning.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;This summary of how lightning forms&lt;/a&gt; on a course website by Dr. David Newman at University of Alaska and &lt;a href=&quot;https://www.weather.gov/safety/lightning-science-electrification&quot; rel=&quot;nofollow noreferrer&quot;&gt;this NOAA page&lt;/a&gt; help explain the main theory on lightning formation.  And &lt;a href=&quot;https://journals.ametsoc.org/view/journals/atsc/43/8/1520-0469_1986_043_0802_ootdoi_2_0_co_2.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Observations of the Distribution of Ice in Hurricanes by Black and Hallett&lt;/a&gt; from 1985 helps indicate what is missing in hurricanes.&lt;/p&gt;&#xA;&lt;p&gt;Basically it looks like with a weaker updraft, when moisture reaches the height of freezing, it &amp;quot;gathers&amp;quot; into the larger ice (graupel and hail) that falls relatively shortly up more, since it rises so slowly.&lt;br /&gt;&#xA;And so you there isn't much supercooled water (and the smaller hail\graupel grows more slowly when it collides and so falls more slowly as well)&#xA;Whereas with a stronger updraft, the more rapid rising motion means the moisture gets higher up before attaining hail/graupel... and so leaving a larger layer with just supercooled water\ice crystals below.  And that supercooled water is the vital thing, causing the heat release when freezing to falling ice.  And so you have different particles with different charges.&lt;/p&gt;&#xA;&lt;p&gt;So only areas of stronger rising motion can form those better depths of &amp;quot;unglaciated&amp;quot; areas with supercooled water.  How do you get more rising motion?&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Pockets of more unstable air (hotter moist air near the ground or cooler air aloft).  These will typically only be found at far extents from the storm, as nearer the center you tend to have moistened and well mixed the entire region.  Sometimes well placed dry air intrusions into a storm may offer a bit of help.&lt;/li&gt;&#xA;&lt;li&gt;Additional forced rising by converging air below... this can be big features like eyewall replacement cycles, shear tilting, or &lt;a href=&quot;https://www.theweatherprediction.com/habyhints3/844/&quot; rel=&quot;nofollow noreferrer&quot;&gt;frictional convergence as a storm makes landfall&lt;/a&gt; or more &lt;a href=&quot;https://journals.ametsoc.org/view/journals/mwre/122/8/1520-0493_1994_122_1897_oolics_2_0_co_2.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;localized embedded supercells&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;The answer for Harvey is probably all of the above.&lt;/strong&gt;  Places like Houston were first in the further extents of the storm the early days and so were able to see the more typical fluctuations of strong rising updrafts and stronger sinking downdrafts more typical of normal thunderstorm convection and the outer rainbands in tropical cyclones.  And then had a storm seeing important structural changes by the time it moved nearer Houston (as marked by the &lt;a href=&quot;https://www.ustornadoes.com/2017/08/30/hurricane-harveys-tornado-action/&quot; rel=&quot;nofollow noreferrer&quot;&gt;significant tornado outbreak&lt;/a&gt;)&#xA;And areas nearer the center of Harvey saw rapid intensification (indicating there was more instability nearer the storm center still), &lt;a href=&quot;https://twitter.com/bmcnoldy/status/901179954150486019?lang=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;eyewall replacement&lt;/a&gt;, plus the usual frictional convergence at landfall all favoring a bit of an uptick in lightning.  Harvey may well have not been too different from most landfalling hurricanes, but had the benefit of rapid intensification to help lightning production some... and it was dark so it could be seen more!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="2958" LastEditDate="2022-07-03T13:11:58.983" LastActivityDate="2022-07-03T13:11:58.983" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20668" PostTypeId="1" CreationDate="2021-01-10T20:58:49.873" Score="2" ViewCount="89" Body="&lt;p&gt;I have a list of geological data.&#xA;The data is for 3 variables: member, level and L+/-&lt;/p&gt;&#xA;&lt;p&gt;These variables correspond to a particular position on a stratigraphic column/chart.&lt;/p&gt;&#xA;&lt;p&gt;I would like help with precisely knowing which level -3 refers to?  Is it the level 3 units from the bottom of the column upwards, or from the top of the column downwards?  Thank you.&lt;/p&gt;&#xA;" OwnerUserId="21623" LastActivityDate="2021-01-10T20:58:49.873" Title="How to read stratigraphy data?" Tags="|geology|" AnswerCount="0" CommentCount="1" ClosedDate="2021-05-16T12:57:45.950" ContentLicense="CC BY-SA 4.0" />
  <row Id="20669" PostTypeId="2" ParentId="20660" CreationDate="2021-01-11T08:26:03.163" Score="-1" Body="&lt;p&gt;My answer will not be complete, but consider one factor: population.&lt;/p&gt;&#xA;&lt;p&gt;Belgium population per year:&lt;/p&gt;&#xA;&lt;p&gt;1990    9,967,000&lt;/p&gt;&#xA;&lt;p&gt;2000    10,251,000 (+10.2%)&lt;/p&gt;&#xA;&lt;p&gt;2009    10,796,000 (+5.3%)&lt;/p&gt;&#xA;&lt;p&gt;2018    11,376,070 (+5.4%)&lt;/p&gt;&#xA;&lt;p&gt;On top of that, you are considering countries with relatively small population increasing significantly (Belgium, Austria, the Netherlands). Most of the population increase is from immigration and high fertility rate of the new population (see the CO2eq impact of &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0959378008001003&quot; rel=&quot;nofollow noreferrer&quot;&gt;about 9tons per capita on the parents due to a new born&lt;/a&gt;), with industrial powerhouses like Germany and Italy where a lot of the production has been delocalized in the same time period (check CO2 of Romania or Spain)&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2021-01-11T08:26:03.163" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20670" PostTypeId="2" ParentId="20499" CreationDate="2021-01-11T12:08:15.550" Score="1" Body="&lt;p&gt;In line with what strawberry-sunshine has answered, and to put it into more layman terms, after a compressive episode there's a distensive one.&lt;/p&gt;&#xA;&lt;p&gt;Imagine you have a volume of sand, and you are compressing it horizontally in one direction, it is confined in the other horizontal direction and the only force acting vertically is gravity.&lt;/p&gt;&#xA;&lt;p&gt;During compression, the sand will reorder itself in response to the applied stress: this reorganization are the equivalent of the thrust faults. You keep applying force until movement is negligible. Then you stop applying it althogether. The weight of the sand will force a second reorganization to adapt to the new conditions. This is the equivalent of a distensive period, and the displacements inside the sand mass are the equivalent of the normal faults developed in the second stage of the orogen.&lt;/p&gt;&#xA;&lt;p&gt;Although reality is more complicated that that, I hope this example helps you understanding why normal faults can be younger than thrust faults.&lt;/p&gt;&#xA;&lt;p&gt;Best regards&lt;/p&gt;&#xA;" OwnerUserId="21611" LastActivityDate="2021-01-11T12:08:15.550" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20671" PostTypeId="2" ParentId="20498" CreationDate="2021-01-11T12:33:24.090" Score="3" Body="&lt;p&gt;The only answer I can come up with is related to &lt;a href=&quot;https://sealevel.colorado.edu/presentation/what-glacial-isostatic-adjustment-gia-and-why-do-you-correct-it&quot; rel=&quot;nofollow noreferrer&quot;&gt;isostasy&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;1 - Poles melt, so there's more water in the oceans.&#xA;2 - As there's more water in the oceans, there's more weight on the oceanic crusts, so they bend, &lt;a href=&quot;https://sealevel.colorado.edu/presentation/what-glacial-isostatic-adjustment-gia-and-why-do-you-correct-it&quot; rel=&quot;nofollow noreferrer&quot;&gt;making deeper some parts of the oceans.&lt;/a&gt;&#xA;3 - The parts of the ocean that are deeper are in the centre of the oceans, far from continental crust. It should be mainly the Pacific Ocean, Indic and Atlantic, but not near Antarctica, as this area is continental crust (lighter) and will be also unloaded from ice.&#xA;4 - As a result, the shape of the Earth crust becomes a bit longer in N-S direction.&#xA;5 - As the mass of the Earth is closer to the rotation axis, it accelerates the spin.&lt;/p&gt;&#xA;&lt;p&gt;Lithospheric density is &lt;a href=&quot;https://en.wikipedia.org/wiki/Isostasy&quot; rel=&quot;nofollow noreferrer&quot;&gt;approximately 2.5 times that of water&lt;/a&gt;, so amount of water in the ocean isn't as important as crust flexion.&lt;/p&gt;&#xA;" OwnerUserId="21611" LastEditorUserId="21611" LastEditDate="2021-01-11T23:10:38.467" LastActivityDate="2021-01-11T23:10:38.467" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20672" PostTypeId="2" ParentId="20659" CreationDate="2021-01-11T12:48:15.803" Score="-1" Body="&lt;p&gt;You should take into account isostasy. As there's more water in the oceans, the crust underneath bends under the weight, creating more room for it. At the same time, continental crust heaves above the oceanic, hence the small value.&lt;/p&gt;&#xA;&lt;p&gt;A question here to be careful about is where the location of the measuring point, as it very well may not be stable.&lt;/p&gt;&#xA;" OwnerUserId="21611" LastActivityDate="2021-01-11T12:48:15.803" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20673" PostTypeId="1" CreationDate="2021-01-10T05:50:29.903" Score="6" ViewCount="91" Body="&lt;p&gt;As titled. How does the hole fell specifically on that region of the stratosphere above the Antarctic and why?&lt;/p&gt;&#xA;" OwnerDisplayName="LamWonders" LastActivityDate="2021-01-21T11:05:30.597" Title="Why is Ozone hole above single area of earth? Why that area?" Tags="|atmosphere|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20674" PostTypeId="1" CreationDate="2021-01-11T19:07:52.093" Score="1" ViewCount="67" Body="&lt;p&gt;I have done some rough calculations of how long it might take humanity: approx 80,000 years (that's taking Earth's population as 7.5 billion, 11,000 litres a day of breathing per person, the weight of 1 litre of air at sea level at 1.225 grams, and the total weight of the atmosphere at 5140 trillion tonnes)&lt;/p&gt;&#xA;&lt;p&gt;Please let me know if my calculations are massively out!&lt;/p&gt;&#xA;&lt;p&gt;My question now is - how long would it take all animal species combined to breathe the equivalent sum total weight of the atmosphere.... and how long would it take all life combined??&lt;/p&gt;&#xA;" OwnerUserId="5381" LastEditorUserId="5381" LastEditDate="2021-01-11T20:09:59.133" LastActivityDate="2021-01-11T20:09:59.133" Title="How long to breathe (the equivalent) of all of the atmosphere?" Tags="|atmosphere|gas|oxygen|troposphere|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20675" PostTypeId="2" ParentId="20498" CreationDate="2021-01-11T19:40:15.677" Score="2" Body="&lt;p&gt;This study seems to suggest that global warming will change oceanic circulation and transfer a net increase of mass to the poles, closer to the axis of rotation, therefore speeding up the spin.&lt;/p&gt;&#xA;&lt;p&gt;article: &lt;a href=&quot;https://www.newscientist.com/article/dn11555-global-warming-will-make-earth-spin-faster/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.newscientist.com/article/dn11555-global-warming-will-make-earth-spin-faster/&lt;/a&gt;&#xA;study: &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2006GL029106&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2006GL029106&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Much of this transfer of mass seems to be to do with water flooding low-lying areas in the northern hemisphere, and I assume that adding to this effect will be lower density frozen water being replaced by higher density liquid water around the poles.&lt;/p&gt;&#xA;" OwnerUserId="5381" LastEditorUserId="5381" LastEditDate="2021-01-11T19:53:39.333" LastActivityDate="2021-01-11T19:53:39.333" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20676" PostTypeId="1" AcceptedAnswerId="20686" CreationDate="2021-01-12T08:03:40.390" Score="3" ViewCount="137" Body="&lt;p&gt;I need to work with historical weather data (temperature and precipitation), we use meteoblue.com.&lt;/p&gt;&#xA;&lt;p&gt;There (&lt;a href=&quot;https://docs.meteoblue.com/en/meteo/data-sources/data-sources#data-sources&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://docs.meteoblue.com/en/meteo/data-sources/data-sources#data-sources&lt;/a&gt;) they write about three different types of models:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;weather reanalysis models&lt;/li&gt;&#xA;&lt;li&gt;weather simulation models&lt;/li&gt;&#xA;&lt;li&gt;satellite (observation) data&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Comparing ERA5 (reanalysis) vs NEMS (simulation):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;daily mean temperature is almost the same in both models&lt;/li&gt;&#xA;&lt;li&gt;ERA often gives 2-4 times higher amounts for total monthly precipitation, which is just too big difference (it's for Europe, I'm interested in past 20 years)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I tried to read about the models, but couldn't find any comparison. Also don't really understand how such big differences might occur and which model shall I use.&lt;/p&gt;&#xA;" OwnerUserId="21631" LastEditorUserId="21631" LastEditDate="2021-01-12T10:01:52.617" LastActivityDate="2021-01-15T15:03:21.340" Title="difference between different meteorological models" Tags="|meteorology|climate-models|era|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20677" PostTypeId="2" ParentId="20601" CreationDate="2021-01-12T11:40:14.440" Score="2" Body="&lt;p&gt;Planets in our solar system have strikingly different chemical compositions - the four rocks closest to the  sun (Mercury, Venus, Earth, Mars) have most of their mass made up of rocky and metallic elements (the centre of the Earth is mainly nickel and iron), whereas the gas giants of Jupiter and Saturn are made up of much lighter and simpler elements (mainly Hydrogen and Helium)&lt;/p&gt;&#xA;&lt;p&gt;Jupiter has hydrogen all the way to its core, where pressures are so intense that a form of 'metallic hydrogen' is thought to exist there. So yes, there are &lt;em&gt;less&lt;/em&gt; step-changes in elemental composition and therefore less step-changes in density - however, density step-changes still do exist where matter (even the same elements) exists in different states under different conditions - e.g. gas, liquid and possibly metallic hydrogen at different pressures and temperatures. That is a feature of chemistry.&lt;/p&gt;&#xA;&lt;p&gt;The reason for the elemental difference in the planets is partly due to the make-up and distribution within the accretion disk, the swirl of elements that existed when our solar system formed. Also, planets that are as big as Jupiter have such a strong gravitational pull that they are able to hold onto (and pull in more) of the lighter elements like hydrogen and helium, which are the most abundant in the universe. Jupiter is actually like a half-there star, sometimes referred to as a 'failed star'.&lt;/p&gt;&#xA;&lt;p&gt;However, the Earth is still large enough and has a protective magnetic shield generated by its iron core that allows its atmosphere not to be blasted away by the solar wind. This means we have both a stable gaseous atmosphere as well as a metallic and rocky interior, meaning a step-change in densities between solids and gases.&lt;/p&gt;&#xA;&lt;p&gt;It is also worth noting though that our gaseous atmosphere is only 60 miles thick, whereas the Earth's radius is about 4,000 miles. The planet is much more of a homogenous solid than you might think, being as we are atmosphere dwellers.&lt;/p&gt;&#xA;" OwnerUserId="5381" LastEditorUserId="5381" LastEditDate="2021-01-12T11:56:30.707" LastActivityDate="2021-01-12T11:56:30.707" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20678" PostTypeId="2" ParentId="20601" CreationDate="2021-01-12T17:21:22.837" Score="1" Body="&lt;p&gt;World is about 4.5 billion years old. At the beginning its density function is linear. Since the beginning world mass loosing its heat. The heat of the earth is high enough to cause convection currents. Convection currents works like an elevator from center to the surface. This convection currents makes the mass inside earth to move upwards, then downwards nonstoppingly, since its formation. This movement center to edge has average 1 mm/year velocity. For 4.5 billion years, thousands of times this tour completed. The action takes place by partial melting. Large ion/charge elements are unwanted in crystal structure and they leave the crystal first during melting. They are transferred to crust via this melt.&#xA;Due to this repeatingly mass translation earth has been developing its layered structure with characterised by step function. The process is called differentiation and time is an element of this function.&lt;/p&gt;&#xA;&lt;p&gt;The differentiation phenomemon is also responsible for plate tectonics; formation of continents, earthquakes, life.&lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="15195" LastEditDate="2021-01-13T14:14:38.833" LastActivityDate="2021-01-13T14:14:38.833" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20679" PostTypeId="1" CreationDate="2021-01-12T21:01:25.667" Score="1" ViewCount="59" Body="&lt;p&gt;Normally, here in New England we consider our weather to somewhat parallel Korea's weather. However, this year it seems to be much colder in Korea. They are having record lows while we are having a relatively mild winter so far.&lt;/p&gt;&#xA;&lt;p&gt;Why would there be such a divergence?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2021-01-12T21:01:25.667" Title="Korea a lot colder than New England this year" Tags="|meteorology|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20680" PostTypeId="2" ParentId="18483" CreationDate="2021-01-13T09:09:03.027" Score="1" Body="&lt;p&gt;Temparate rainforests are characterized by two factors&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Non-Freezing weather (thou still cold) Average temperatures 39-55 degrees Fahrenheit (Warm oceanic currents omit any periodic freeze)&lt;/li&gt;&#xA;&lt;li&gt;Rain exceeding 55+ inches a year.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The Geographic factors that influence them, Mountains on one side and a large body of water where warm currents may flow.&#xA;Temperate rainforests in Appalachia, are influenced by the Great Lakes.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-01-13T09:09:03.027" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20681" PostTypeId="2" ParentId="8222" CreationDate="2021-01-13T18:04:24.477" Score="3" Body="&lt;p&gt;A map of measurements can be found &lt;a href=&quot;https://en.wikipedia.org/wiki/Gravity_of_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;This appears to show that some of the highest values are found in the Andes and in parts of the Hymalayas.&lt;/p&gt;&#xA;&lt;p&gt;I find this more than unexpected, so I suspect that this is the gravity referenced to some fixed height above sea-level rather than the surface gravity.&lt;/p&gt;&#xA;&lt;p&gt;Jack Black's answer using a small sphere outside the surface seemed to me too extreme to establish the maximal case for real hills. It seems to me that an extreme model that looked at the maximum effect of a non-equilibrium covering be more definitive. So I have looked at the effect of a &amp;quot;mountain&amp;quot; that was so wide that it could be treated as a covering of uniform thickness across the entire globe.&lt;/p&gt;&#xA;&lt;p&gt;Taking the field of the Earth at height h above the surface, and without covering we have&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$g_0 = 5510 \cdot G \cdot \frac{4 \pi}{3} \frac{R^3}{(R+h)^2} \ \ \ \ \ \ \ \ \ \ \ \frac{m}{s^2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;(5510 &lt;span class=&quot;math-container&quot;&gt;$\frac{kg}{m^3}$&lt;/span&gt; being the mean density of the Earth, other symbols taking their usual meanings). The rate of change just above the surface is &lt;span class=&quot;math-container&quot;&gt;$$-2 \cdot 5510 \cdot G \cdot \frac{4 \pi}{3} \ \ \ \ \ \ \ \ \ \ \frac{m}{s^2m}$$&lt;/span&gt; The rate of change of g at the surface of sphere with covering density &lt;span class=&quot;math-container&quot;&gt;$ \rho$&lt;/span&gt; must then be &lt;span class=&quot;math-container&quot;&gt;$$3 \cdot \rho \cdot G \cdot \frac{4 \pi}{3} \ \ \ \ \ \ \ \ \ \frac{m}{s^2m}$$&lt;/span&gt;&#xA;It seems that the uniform surface covering must have a density more than 2/3 of the mean density of the Earth beneath it if gravity is to increase. This would be a rock with specific gravity of more than 3.67 if there is to be any chance that the gravity at the top of the &amp;quot;mountain&amp;quot; exceeds that at the bottom.  The S.G. of the densest basalt is less than 3.1, and granite is even lighter (below 2.8).&lt;/p&gt;&#xA;&lt;p&gt;This means that there is no realistic chance that a mountainous coating could result in an increase in gravity.&lt;/p&gt;&#xA;&lt;p&gt;So the situation where hills/mountains might provide gravitational increases would be where we have steep inclines rising out of deep sea, as these provide an increase in density at levels below the sea-level surface. They would still not provide increases above standard gravity unless the total crust thickness in the region was less than average.&lt;/p&gt;&#xA;" OwnerUserId="21640" LastEditorUserId="21640" LastEditDate="2021-01-14T23:25:09.443" LastActivityDate="2021-01-14T23:25:09.443" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20683" PostTypeId="2" ParentId="8222" CreationDate="2021-01-13T22:08:13.750" Score="5" Body="&lt;p&gt;According to the gravity map below from NASA's GRACE, the mountains you'd want to try for this experiment would be the Andes - they have the highest positive gravity anomaly with sea level quite nearby.&lt;/p&gt;&#xA;&lt;p&gt;However, lets do a bit of calculation based on this data: The map shows that the coast near the Andes is approximately -20 miligal (a unit of gravitational acceleration) and the centre of the Andes mountain range is around +70 miligal - an overall differential of +90 miligal at the middle of the mountains.&lt;/p&gt;&#xA;&lt;p&gt;The high point on the Andes is about 7000 metres from sea level. The standard value used in geodesy (from a physics stack exchange answer, link below) is a reduction of 0.3086 miligals per meter of increased altitude. At 7000 metres, that gives us a value of -2160 miligal, or -2.16 gal, which is equivalent to a change of -0.0216m/s/s - significantly outstripping the gravity anomaly on the map (which is modelled on a theorised homogenous spherical earth)&lt;/p&gt;&#xA;&lt;p&gt;So the answer to your question is no- the mountain tops in areas with highest gravity anomalies will still have (very slightly!) lower gravity than nearby sea level areas&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/8Uqgg.jpg&quot; alt=&quot;GRACE gravity anomaly map&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;image source: &lt;a href=&quot;https://www.jpl.nasa.gov/images/new-views-of-earths-gravity-field-from-grace/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.jpl.nasa.gov/images/new-views-of-earths-gravity-field-from-grace/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;gravity calculation: &lt;a href=&quot;https://physics.stackexchange.com/questions/232878/do-we-feel-0-4-less-body-weight-on-mount-everest#:%7E:text=That%27s%20a%20reduction%20of%200.28,Everest&quot;&gt;https://physics.stackexchange.com/questions/232878/do-we-feel-0-4-less-body-weight-on-mount-everest#:~:text=That's%20a%20reduction%20of%200.28,Everest&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="5381" LastEditorUserId="5381" LastEditDate="2021-01-14T08:22:44.187" LastActivityDate="2021-01-14T08:22:44.187" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20684" PostTypeId="1" AcceptedAnswerId="20736" CreationDate="2021-01-14T07:11:28.647" Score="2" ViewCount="315" Body="&lt;p&gt;The Great Pyramid of Giza is made from blocks of limestone quarried from the Giza plateau. The pyramid is composed up of about 200 layers, with individual  blocks varying in thickness from 20 to 60 inches.  How feasible would it be to identify which layers of limestone in the quarry were used in the various layers of the pyramid? For example, if a core sample were taken from the quarry could individual blocks from the pyramid be matched to a position along the core?&lt;/p&gt;&#xA;" OwnerUserId="21651" LastActivityDate="2024-01-27T23:37:01.263" Title="Stratigraphy of limestone applied to the Great Pyramid of Giza" Tags="|geology|geochemistry|stratigraphy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20685" PostTypeId="1" CreationDate="2021-01-14T21:40:34.283" Score="3" ViewCount="153" Body="&lt;p&gt;I posted this question on Engineering Stack Exchange as well. I'm not sure if here or there is the better place. There is no agriculture stack exchange (much as I wish there was) so I am posting there as well as here.&lt;/p&gt;&#xA;&lt;p&gt;I need to choose where to drill an agricultural well. I am trying to get as much water as possible (at least 100 gpm).&lt;/p&gt;&#xA;&lt;p&gt;I am considering hiring a guy who claims to be able to find water using a device called an ABEM WADI. My understanding is that this devices uses VLF signals from far away transmitters to identify fractures in the ground. He says he walks in a straight line in a candidate area for well drilling, and looks for fractures noted on the screen of the WADI. He claims that areas with a certain type of fracture (I think he said 45° fractures were the best) are more likely to yield a lot of water.&lt;/p&gt;&#xA;&lt;p&gt;To what extent is this method scientifically valid? It sounds legit, but methods of &amp;quot;dousing&amp;quot; or &amp;quot;witching&amp;quot; for water are often little more than divination, so I'm skeptical. I googled around and found some scientific papers about VLF-EM scanning, but I lack the science/engineering chops to interpret them.&lt;/p&gt;&#xA;" OwnerUserId="19194" LastEditorUserId="2470" LastEditDate="2021-08-28T10:05:42.933" LastActivityDate="2021-08-28T10:05:42.933" Title="Is VLF-EM scanning for fractures a valid way to find groundwater for a well?" Tags="|hydrology|water|groundwater|drilling|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20686" PostTypeId="2" ParentId="20676" CreationDate="2021-01-15T15:03:21.340" Score="8" Body="&lt;p&gt;In general, the relation between the three datasets is as follows:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The simulation model is initiated with a set of boundary and initial conditions, and will on the long-term provide good mean conditions. However, depending on the frequency of data assimilation, the results on short-term time spans can deviate from the observations, due to internal variability of the model. Besides, models aren't perfect and sometimes have biases for some variables.&lt;/li&gt;&#xA;&lt;li&gt;In contrast, the satellite data provides observations. These are of course limited by technical aspects, but as indicated by the table in Section 3 of the link you provided, the quality of the precipitation measurements is very good. However, satellites often have a poorer temporal/spatial resolution than models (a satellite can't be everywhere at once and depending on the type, cannot measure at a very high resolution).&lt;/li&gt;&#xA;&lt;li&gt;The reanalysis is a combination of the model simulation and the observations, where both sets are merged (via data assimilation) to provide a coherent dataset. This provides a dataset that can be considered 'pseudo-observations' (they are often used as continental-scale or global scale 'observation' datasets in climate studies), but without the poor spatial/temporal resolution of satellite observations. The biases in the reanalyses should be lower than in the original weather simulation, but may still be present.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Concerning the difference between temperature and precipitation: temperature is much easier to correctly simulate than precipitation (e.g. because of the dry/wet-day transition). As such, on a monthly scale, precipitation biases might be already quite large. For more information on precipitation biases, this paper might be relevant: &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2010jd014532&quot; rel=&quot;noreferrer&quot;&gt;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2010jd014532&lt;/a&gt; (Stephens et al. (2010): The dreary state of precipitation in global models)&lt;/p&gt;&#xA;&lt;p&gt;In essence, the dataset you want to use should depend on your needs. If spatial/temporal coverage and historical data is the most important, the reanalysis is probably your best choice. If you want to know more about this dataset and its biases, this article is a good starting point: &lt;a href=&quot;https://hess.copernicus.org/articles/24/2527/2020/&quot; rel=&quot;noreferrer&quot;&gt;https://hess.copernicus.org/articles/24/2527/2020/&lt;/a&gt; (Tarek et al. (2020): Evaluation of the ERA5 reanalysis as a potential reference dataset for hydrological modelling over North America). Or, if your goal is impact assessment, you might immediately check this one: &lt;a href=&quot;https://essd.copernicus.org/articles/12/2097/2020/&quot; rel=&quot;noreferrer&quot;&gt;https://essd.copernicus.org/articles/12/2097/2020/&lt;/a&gt; (Cucchi et al. (2020): WFDE5: bias-adjusted ERA5 reanalysis data for impact studies)&lt;/p&gt;&#xA;" OwnerUserId="15226" LastActivityDate="2021-01-15T15:03:21.340" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20687" PostTypeId="2" ParentId="20619" CreationDate="2021-01-16T21:36:10.197" Score="3" Body="&lt;p&gt;Dyeing agate is a common practice- the stone is real, but it's been cosmetically altered. The stone gets soaked in a chemical solution, which is absorbed into the microscopic pores in the stone.  Whatever dye the person who made these coasters used must have been water-soluble.  So, yes, cold water would also cause the pigments to bleed.&lt;/p&gt;&#xA;" OwnerUserId="21662" LastActivityDate="2021-01-16T21:36:10.197" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20688" PostTypeId="2" ParentId="8222" CreationDate="2021-01-17T01:11:00.720" Score="0" Body="&lt;p&gt;The gravitational acceleration decreases with altitude. A person for example; flying at an altitudde of 30,000 feet; above sea level over say............ mountains will feel more gravity than someone at the same elevation but over the sea. On the other hand, a person standing on the Earth's surface feels less gravity when the elevation is higher than say Gravitational acceleration at height above sea level. Though minute, the further from the Earth's center of mass.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-01-17T01:11:00.720" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20689" PostTypeId="2" ParentId="20398" CreationDate="2021-01-17T01:36:39.630" Score="2" Body="&lt;p&gt;Channelizing a river keeps it from overflowing its banks as often, which prevents flooding.  However, wetlands need a certain degree of said flooding to function as a biome.&lt;/p&gt;&#xA;" OwnerUserId="21662" LastActivityDate="2021-01-17T01:36:39.630" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20690" PostTypeId="1" AcceptedAnswerId="20696" CreationDate="2021-01-17T02:16:06.557" Score="2" ViewCount="484" Body="&lt;p&gt;I started thinking about this after seeing several articles about falling trees, in particular a few articles about very large trees falling in Los Angeles and New York City. Plus, just thinking about all the wildfires in the Western United States started by trees falling on electrical wires. Although I haven't done extensive research, I did some searching and found the following:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.tum.de/nc/en/about-tum/news/press-releases/details/34892/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Trees and climate change: Faster growth, lighter wood&lt;/a&gt;. This article discusses how &amp;quot;wood density of European trees decreasing continuously since 1870.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;So is this a current concern and a global phenomena? Are trees growing faster, but are less strong. Combining this thought with the fact that &lt;a href=&quot;https://www.scientificamerican.com/article/the-worlds-winds-are-speeding-up/&quot; rel=&quot;nofollow noreferrer&quot;&gt;winds are getting stronger&lt;/a&gt; in North America seems very unsettling.&lt;/p&gt;&#xA;" OwnerDisplayName="user21648" LastEditorDisplayName="user21648" LastEditDate="2021-01-17T02:24:33.157" LastActivityDate="2021-01-19T05:17:19.287" Title="Is a hotter climate making trees grow faster and have lighter wood?" Tags="|meteorology|climate-change|soil-science|" AnswerCount="3" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="20691" PostTypeId="2" ParentId="20690" CreationDate="2021-01-17T16:09:41.530" Score="1" Body="&lt;p&gt;Nothing to do with climate change . Faster growth produces somewhat lower density and strength. There are strength tables for wood written more than 50 years ago that have separate listings for &amp;quot;new &amp;quot; growth and &amp;quot;old&amp;quot; growth. &amp;quot;New &amp;quot; growth being trees growing faster in clear cut areas with less competition for water, light and nutrients. Old is trees in areas that not previously been harvested and grew slower in crowded conditions.  Power line failure is related to the increase in numbers of power lines in expanding populated areas, and to how much money utilities spend trimming trees near the power lines.  When I drove in western Europe  in the 80's , I was impressed by how many of the forests had been &amp;quot;managed&amp;quot;. Large old trees had been planted in regularly spaced straight lines ,maximizing growth speed = lower density . As silviculture is a minor hobby of mine I expect I noticed things others would not.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2021-01-17T16:09:41.530" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20692" PostTypeId="2" ParentId="20398" CreationDate="2021-01-18T04:07:59.463" Score="0" Body="&lt;p&gt;What is the purpose of channeling a river, to make it move water more quickly. Moving water more quickly is also called draining water more effectively, If it draining water more quickly the land around it gets drier.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2021-01-18T04:07:59.463" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20693" PostTypeId="1" CreationDate="2021-01-18T02:32:11.933" Score="1" ViewCount="159" Body="&lt;p&gt;I am doing soil related calculations for moisture content and the soil characteristics I need (among others) is the content of the soil as a percentage for:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;sand&lt;/li&gt;&#xA;&lt;li&gt;clay&lt;/li&gt;&#xA;&lt;li&gt;organic matter&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I am thinking I take the the sand content (in g) divide by 1000 to get sand percentage content and like wise for clay (except use the clay content value in g). For organic matter do I take the soil organic content they provide in dc/kg and divide by 10000? It seems some areas will have a very high organic material content then. I would expect somewhere between 1% and 6% but some areas if I use that method would be like 44%.&lt;/p&gt;&#xA;" OwnerDisplayName="Eric Laukonen" LastActivityDate="2021-01-20T21:27:43.130" Title="What method do I use to derive the organic material content (as a percentage) per layer in SoilGrids" Tags="|soil|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20694" PostTypeId="2" ParentId="10245" CreationDate="2021-01-18T20:54:31.683" Score="1" Body="&lt;p&gt;Answer #43 above is absolutely correct. Unless water molecules are split (disintegrate) into hydrogen and oxygen, they almost never leave Earth into space. We have practically the same amount of water on Earth as it had when first created.  After evaporation, it returns as rain. Every time. Every place. This is why I become crazy when government officials tell us that we are running out of water. This is absurd. We can't run out of water. But it certainly can be mismanaged -- but then, that's the government's job. Isn't it?&lt;/p&gt;&#xA;" OwnerUserId="21668" LastEditorUserId="6016" LastEditDate="2021-01-19T21:51:34.030" LastActivityDate="2021-01-19T21:51:34.030" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20695" PostTypeId="2" ParentId="20693" CreationDate="2021-01-18T21:05:09.953" Score="1" Body="&lt;p&gt;All weight percentages are calculated using the same formula:&lt;/p&gt;&#xA;&lt;p&gt;Mass Fraction/Total Sample Mass&lt;/p&gt;&#xA;&lt;p&gt;There are two different values for organic material in a soil and they're derived by different techniques:&lt;/p&gt;&#xA;&lt;p&gt;If you want to know how much bioavailable organic material is in the soil I was taught to use a chemical reagent to oxidise and strip organic carbon from the soil, saturated soil samples are weighed before and after the test to estimate the weight of organic matter so removed or a titration can be performed on the soil leachate to determine the exact amount of carbon oxidised.&lt;/p&gt;&#xA;&lt;p&gt;If you want the total soil carbon weigh a dried sample then crush it and put it in a crucible over a Bunsen Burner until it stops smoking, the sample also darkens as it starts to burn and then turns pale once all the carbon has been burned out of it, and reweigh it the difference is all the soil carbon.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2021-01-18T21:05:09.953" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20696" PostTypeId="2" ParentId="20690" CreationDate="2021-01-18T21:36:29.377" Score="1" Body="&lt;p&gt;Many tree species do grow faster in climates that are warmer than their native range, especially where the added heat is combined with moist conditions, and faster growth is generally associated with lower density wood. This is why a lot of New Zealand's plantation pine is only good for paper pulp, the warmer wetter climate means that the trees grow fast and have wet low density wood that doesn't have good structural performance. But this doesn't really account for most of the changes seen in European forests over the last 150 years; trees also grow faster, and therefore have &amp;quot;lighter&amp;quot; wood when grown in lower density stands. In managed forests trees are separated at intervals convenient to human maintenance staff and their equipment and are thus considerably farther apart than they would be if they had grown from seed in a wild setting and as tree farm mechanisation has increased so has tree spacing in plantation stands. Climate change could alter wood densities in the long run but at this stage we aren't seeing those effects in timber yet, it may be effecting young stands right now but we won't see the results for a number of years.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2021-01-18T21:36:29.377" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20697" PostTypeId="2" ParentId="20642" CreationDate="2021-01-19T00:38:09.973" Score="0" Body="&lt;p&gt;I would say it's reasonable to infer that the strata stay at roughly the same dip angle and thickness in areas not directly visible on the chart you're using.&lt;/p&gt;&#xA;" OwnerUserId="21662" LastActivityDate="2021-01-19T00:38:09.973" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20698" PostTypeId="2" ParentId="20690" CreationDate="2021-01-19T05:17:19.287" Score="-1" Body="&lt;p&gt;A one degree rise in temperature is barely a noticeable change. The biggest change is additional atmospheric carbon dioxide leads to sustained growth and longer growing seasons. CO2 availability is prime indicator for sustained plant growth. Alot of the tree's in LA and New York........ Are old. Some 2-3 centuries, which is why some are falling or dying.&#xA;But faster growth rates do yield less wood density because tree rings. When faced with stressful or unfavorable conditions, a tree might hardly grow at all. Even in ideal climates Trees have to Compete for sunlight, water and nutrients. Overall a warmer climate certainly benefits tree growth; certainly not kill it.  &lt;a href=&quot;https://i.stack.imgur.com/je3dr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/je3dr.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-01-19T05:17:19.287" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20699" PostTypeId="2" ParentId="20693" CreationDate="2021-01-19T08:58:41.743" Score="1" Body="&lt;p&gt;If you are not in the position of following the steps suggested in Ash's answer, I'd suggest you to rely on existing data, as the ISRIC dataset &amp;quot;WISE derived soil properties on a 30 by 30 arc-seconds global grid&amp;quot;, developed at Wageningen university and available &lt;a href=&quot;https://data.isric.org/geonetwork/srv/eng/catalog.search#/metadata/dc7b283a-8f19-45e1-aaed-e9bd515119bc&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. This dataset is originally based on the FAO-Unesco Soil Map of the World (DSMW). Of course, the 5 arc-minutes resolution (about 9.2 km at the equator) might be a little coarse if you are conducting a specific site project, but it could be a useful reference if your domain is broader.&lt;/p&gt;&#xA;&lt;p&gt;Additional information about the project available &lt;a href=&quot;https://www.isric.org/projects/world-inventory-soil-emission-potentials-wise&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Methodology and main variables described &lt;a href=&quot;https://library.wur.nl/WebQuery/wurpubs/fulltext/400244&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="8087" LastActivityDate="2021-01-19T08:58:41.743" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20700" PostTypeId="1" AcceptedAnswerId="20701" CreationDate="2021-01-19T15:23:47.953" Score="1" ViewCount="54" Body="&lt;p&gt;my first time here!&lt;/p&gt;&#xA;&lt;p&gt;I was going down the rabbit hole after watching a video on YouTube that made me want to read about it on Wikipedia.&lt;/p&gt;&#xA;&lt;p&gt;It led me to this Picture:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vDliJ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vDliJ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;(&lt;a href=&quot;https://en.wikipedia.org/wiki/File:Varandha_ghad.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;View from Varandha Pass near Mahad in Maharashtra, with numerous waterfalls&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;I'm guessing that those lines are not natural, but I know very little about this so I thought to come and ask the experts!&#xA;It looks like a kind of terracing to me, but I've no idea how big they are from the angle of the Photo and the Wiki article doesn't appear to explain it, either.&#xA;I can't find a tag for it, and can't create one, but this is part of a mountain range that is parallel to the west coast of the Indian peninsula, they are, apparently the &lt;a href=&quot;https://www.wikiwand.com/en/Western_Ghats&quot; rel=&quot;nofollow noreferrer&quot;&gt;Western Ghats&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Can anyone help me out and tell me what's going on here?&lt;/p&gt;&#xA;&lt;p&gt;Thank you very much indeed!&lt;/p&gt;&#xA;" OwnerUserId="21671" LastEditorUserId="6298" LastEditDate="2021-01-20T07:04:12.943" LastActivityDate="2021-01-24T23:43:04.077" Title="Terracing in Mahad" Tags="|geography|mountains|structural-geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20701" PostTypeId="2" ParentId="20700" CreationDate="2021-01-19T17:29:18.277" Score="8" Body="&lt;p&gt;The Deccan Traps are the geological formation that make up the Western Ghats in India. They were formed by massive volcanic eruptions that formed flood basalts.  These are layers of lava that are extruded from fissures and spread over wide areas of relatively flat ground or over flat sea floor.&lt;/p&gt;&#xA;&lt;p&gt;The terracing is natural. Each of the layers that you see in the picture represents a single eruptive event. When the lava spreads out out the top and bottom of the flow cool rapidly and the rapid cooling breaks up the rock. The middle of the flow cools slower, cracks less and doesn't erode as easily.&lt;/p&gt;&#xA;&lt;p&gt;The total thickness of flows in the Deccan Traps may be up to 2000 metres, with individual flows between 5 and 50 metres thick.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Deccan_Traps&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Deccan_Traps&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21672" LastEditorUserId="6467" LastEditDate="2021-01-24T23:43:04.077" LastActivityDate="2021-01-24T23:43:04.077" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20702" PostTypeId="2" ParentId="20685" CreationDate="2021-01-19T17:40:49.257" Score="1" Body="&lt;p&gt;VLF-EM is a perfectly valid technique for helping an expert decide where best to locate wells in geological environments where water is largely flowing in fractures. Typically it is a useful technique in fractured bedrock where a successful water well needs to intercept connected fractures or fissures. In other geologies, for instance porous sandstones, it would be much less useful. Drilling for water in fractured terrains is always a slightly risky proposition; geophysical techniques help site wells to intercept fractures but they can't guarantee yields, which will depend on how large the fractures are and how interconnected they are. A reputable contractor should be prepared to provide references from satisfied clients and that is a good starting point.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastEditorUserId="21672" LastEditDate="2021-01-29T11:26:24.283" LastActivityDate="2021-01-29T11:26:24.283" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20703" PostTypeId="2" ParentId="13366" CreationDate="2021-01-19T20:23:54.540" Score="-1" Body="&lt;p&gt;The loss of liquid water on Mars was also due to the planet losing its magnetosphere. During the Hesperian period (about 3500 mya) the iron core stopped rotating fast enough to create a planet-wide magnetic field of the type Earth has. Because of this, the Martian atmosphere was no longer protected from solar wind, which caused it to erode away to its current (very low) density. Without enough gases in the atmosphere to generate a greenhouse effect, Mars became much colder and drier. This is why there's no liquid water on its surface at present.&lt;/p&gt;&#xA;" OwnerUserId="21662" LastActivityDate="2021-01-19T20:23:54.540" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20704" PostTypeId="1" AcceptedAnswerId="20705" CreationDate="2021-01-20T06:15:34.553" Score="5" ViewCount="139" Body="&lt;p&gt;In my understanding, in Global Chemical Transport Models,  initial conditions are provided by spinning up the model or through previous simulation.  But, can I use the same initial condition that I prepared for baseline simulation for sensitivity analysis too?&lt;/p&gt;&#xA;&lt;p&gt;For example:&#xA;I am trying to  see the changes in the surface ozone for the year 2010. I conducted baseline simulation from beginning of 2009  till the end of 2010 with 2009 taken as spin-up period.&lt;/p&gt;&#xA;&lt;p&gt;Then, to see the changes from anthropogenic emission, I turned off anthropogenic emission sources and would like to simulate it for the year 2010. In this case can I use the initial condition values that I prepared from the baseline simulation or do I have to spin-up from the beginning?&lt;/p&gt;&#xA;" OwnerUserId="20906" LastEditorUserId="20906" LastEditDate="2021-01-20T07:59:20.677" LastActivityDate="2021-01-21T16:26:45.800" Title="Correct way to spin-up for sensitivity analysis in a Global Chemical Transport Models" Tags="|atmosphere|atmosphere-modelling|atmospheric-chemistry|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20705" PostTypeId="2" ParentId="20704" CreationDate="2021-01-20T08:18:01.663" Score="2" Body="&lt;p&gt;welcome to ES.&lt;/p&gt;&#xA;&lt;p&gt;I'm not experienced in Chemical Transport Model, so my reply will be more on &amp;quot;general terms&amp;quot; and I'd be more than happy to see more specific answers.&lt;/p&gt;&#xA;&lt;p&gt;That being told, in my experience with land surface and hydrological models, the spin-up period is heavily model- and application- specific. In some applications, for hydrological analysis of complex large basins, the spin up period of the model could require also some years of simulation. This is needed to stabilize all the &amp;quot;reservoirs&amp;quot; that the model uses to simulate the complex interactions between surface and subsurface hydrology. Using a &amp;quot;too short&amp;quot; spin-up period would seriously affect your results, but what is &amp;quot;too short&amp;quot; depends on your model.&lt;/p&gt;&#xA;&lt;p&gt;The sort answer to your question would therefore be: &amp;quot;the longer the better&amp;quot;, but this would also depend on the complexity of your model and the computing time that you need to dedicate to the spin-up period (i.e., if your model takes a week to simulate a month, then I would not suggest you to take a spin-up period of a year...).&lt;/p&gt;&#xA;&lt;p&gt;So if this is not the case, and your model is pretty fast, I'd replicate the data that you prepared for the year 2009 as input for a &amp;quot;fake&amp;quot; 2008 and run the simulation from 2008 to 2010. Looking at the outputs of your model, then, you will see if there are weird trends that you could attribute to the spin-up going beyond the &amp;quot;fake&amp;quot; 2008. If this is not enough, you could use the same data also for 2007, and so on.&lt;/p&gt;&#xA;&lt;p&gt;Additional info also &lt;a href=&quot;https://www.researchgate.net/post/What-does-one-mean-by-Model-Spin-Up-Time&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;EDIT: I'm just realizing that yesterday I replied only to part of your question. My apologies.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I'll try to respond here to the question you made in your comment:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;So that means even if I take the initial condition form year 2009, I&#xA;still need to spin up the model, if I do some other analysis (such as&#xA;sensitivity)? can't I directly use the initial condition from 2009&#xA;from baseline simulation in sensitivity simulation instead of spinning&#xA;up again, especially if the spin up time is very long and I would want&#xA;to save computation time?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This really depends on the inertia of the system that you are analyzing. It is very unlikely (at least, to me, and remember that I'm not familiar with these models) that you could get a system that is going to stabilize to different conditions (like removing the anthropogenic emissions) simulating just one year.&lt;/p&gt;&#xA;&lt;p&gt;Look for instance at this example that comes from the User Guide of an open access hydrological model (LISFLOOD documentation, &lt;a href=&quot;https://ec-jrc.github.io/lisflood-code/3_step5_model-initialisation/&quot; rel=&quot;nofollow noreferrer&quot;&gt;taken from here&lt;/a&gt;):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;To better understand the impact of the initial model state on the&#xA;results of a simulation, let’s start with a simple example. The Figure&#xA;below shows 3 LISFLOOD simulations of soil moisture for the upper soil&#xA;layer. In the first simulation, it was assumed that the soil is&#xA;initially completely saturated. In the second one, the soil was&#xA;assumed to be completely dry (i.e. at residual moisture content).&#xA;Finally, a third simulation was done where the initial soil moisture&#xA;content was assumed to be in between these two extremes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Yryfo.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Yryfo.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So, this part of the system (top layer soil moisture), is apparently stabilizing in about 150-200 days. After this period, the initial conditions (with and without spin-up) are basically irrelevant.&lt;/p&gt;&#xA;&lt;p&gt;If you go to analyze other variables instead:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/M2DCL.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/M2DCL.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This part of the system, instead, takes about 2000 days to stabilize. This means that a proper initialization of this particular model in this particular application is crucial to get reliable results in &amp;quot;short&amp;quot; (&amp;lt;2000 days in this case) simulations.&lt;/p&gt;&#xA;&lt;p&gt;Now, imagine that your system has a certain inertia to stabilize after a shock in the emission level (from the example you made in your question): if your situation is similar to the one in the first figure, one year spin-up would be enough and the comparison of the second year with and without anthropogenic emissions would give you something more or less informative. If your system has a slow response as the one in the second figure, then your results would be completely wrong even with the spin-up that you proposed.&lt;/p&gt;&#xA;" OwnerUserId="8087" LastEditorUserId="8087" LastEditDate="2021-01-21T16:26:45.800" LastActivityDate="2021-01-21T16:26:45.800" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20706" PostTypeId="1" AcceptedAnswerId="20718" CreationDate="2021-01-20T21:16:20.230" Score="3" ViewCount="224" Body="&lt;p&gt;I'm reading about the derivation of shallow water equations, and I have a hard time understanding why&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ w(\eta) = \frac{D\eta}{Dt}$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$w$&lt;/span&gt; is the vertical velocity, &lt;span class=&quot;math-container&quot;&gt;$\eta$&lt;/span&gt; is the (top or bottom) vertical boundary of the layer and &lt;span class=&quot;math-container&quot;&gt;$D/Dt$&lt;/span&gt; is the material derivative.&lt;/p&gt;&#xA;&lt;p&gt;In Atmospheric and Oceanic Fluid Dynamics (2nd ed. 2017, chapter 3.1.2), Vallis gives the following explanation:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;At the top the vertical velocity is the material derivative of the&#xA;position of a particular fluid element. But the position of the fluid&#xA;at the top is just &lt;span class=&quot;math-container&quot;&gt;$\eta$&lt;/span&gt;, and therefore&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ w(\eta) = \frac{D\eta}{Dt}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Why is the vertical velocity at the top the material derivative?&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Edit:&lt;/em&gt; Added a schematic illustration of the shallow layer. As you see, &lt;span class=&quot;math-container&quot;&gt;$\eta$&lt;/span&gt; is not assumed to be constant. &lt;a href=&quot;https://i.stack.imgur.com/WyYWR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WyYWR.png&quot; alt=&quot;Shallow layer&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21677" LastEditorUserId="21677" LastEditDate="2021-01-21T17:03:56.583" LastActivityDate="2021-01-22T14:49:56.833" Title="Deriving shallow water equations: why is the vertical velocity equal to the material derivative of the surface level?" Tags="|oceanography|fluid-dynamics|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20708" PostTypeId="1" CreationDate="2021-01-21T00:30:46.663" Score="1" ViewCount="41" Body="&lt;p&gt;Whats the difference between Kenorland and Arctica? Is it believed that both existed or is it a matter of choosing one or the other?&lt;/p&gt;&#xA;&lt;p&gt;Both consist of Laurentia, Baltica, and Ur.&#xA;But Kenorland includes Kalaharia while Arctica includes the Siberian Craton.&lt;/p&gt;&#xA;" OwnerUserId="6615" LastActivityDate="2021-01-21T00:30:46.663" Title="Difference between Kenorland and Arctica" Tags="|paleogeography|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20709" PostTypeId="2" ParentId="20706" CreationDate="2021-01-21T01:11:35.973" Score="2" Body="&lt;p&gt;As a refresher, let's refer back to the definition of the material derivative: &lt;span class=&quot;math-container&quot;&gt;$$\frac{D}{Dt}=\frac{\partial}{\partial t}+u\frac{\partial}{\partial x}+v\frac{\partial}{\partial y}+w\frac{\partial}{\partial z}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;If we apply it to &lt;span class=&quot;math-container&quot;&gt;$\eta$&lt;/span&gt;, then we get:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{D \eta}{Dt}=\frac{\partial \eta}{\partial t}+u\frac{\partial\eta}{\partial x}+v\frac{\partial\eta}{\partial y}+w\frac{\partial\eta}{\partial z}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Let's, for a second, consider that &lt;span class=&quot;math-container&quot;&gt;$\eta$&lt;/span&gt; is the height of the fluid. We can replace &lt;span class=&quot;math-container&quot;&gt;$\eta$&lt;/span&gt; with &lt;span class=&quot;math-container&quot;&gt;$z$&lt;/span&gt; evaluated at the fluid level. Thus, we get &lt;span class=&quot;math-container&quot;&gt;$$\frac{Dz}{Dt}|^{fluid}=\frac{\partial z}{\partial t}|^{fluid}+u\frac{\partial z}{\partial x}|^{fluid}+v\frac{\partial z}{\partial y}|^{fluid}+w\frac{\partial z}{\partial z}|^{fluid}$$&lt;/span&gt;&#xA;Since there is only one Eulerian derivative that is dependent on &lt;span class=&quot;math-container&quot;&gt;$z$&lt;/span&gt;, it follows&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{D\eta}{Dt}=\frac{Dz}{Dt}|^{fluid}=w\frac{\partial z}{\partial z}|^{fluid}=w|^{fluid}=w(\eta)$$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-01-21T01:11:35.973" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20710" PostTypeId="2" ParentId="19159" CreationDate="2021-01-21T02:52:29.973" Score="1" Body="&lt;p&gt;I highly recommend &amp;quot;The Story of Earth&amp;quot;, by Robert M. Hazen.  The title sounds like a children's book, but it's actually a very good starting place for learning about historical geology, which is essential for understanding other aspects of earth science. It's a very accessible look at how planets form, and it won't cost you nearly as much as the average geology textbook.&lt;/p&gt;&#xA;" OwnerUserId="21662" LastActivityDate="2021-01-21T02:52:29.973" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20711" PostTypeId="2" ParentId="9505" CreationDate="2021-01-21T03:12:43.923" Score="4" Body="&lt;p&gt;Although the Martian crust has a similar set of the most-abundant elements as Earth's -- for instance, on both planets oxygen is #1 and silicon #2 -- there are some differences.  Compared with Earth's crust, the Martian version has more iron and magnesium, and less aluminum, calcium, and alkali metals.  The top five elements on Mars are shown &lt;a href=&quot;https://www.lpi.usra.edu/education/IYPT/Mars.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;:  oxygen, silicon, &lt;strong&gt;iron&lt;/strong&gt;, aluminum, &lt;strong&gt;magnesium&lt;/strong&gt; where the elements in bold rank above their placements in the Earthly crust composition.  Calcium and the alkali metals sodium and potassium are further down the list, lower-ranked on Mars than on Earth.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Looking for America (and Eurasia, Africa, ...)&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Except for mermaids, mermen (their masculine counterparts), and maybe some islanders, we all do not just live on Earth's crust.  We live on &lt;em&gt;continental&lt;/em&gt; crust, with its granite-rich rock composition.  This is distinguished from the ocean crusts based primarily on basalt and other mafic rocks.&lt;/p&gt;&#xA;&lt;p&gt;Mars, despite probably once being a wet world, shows no evidence of any similar continental crust formation [1].  A study of rocks from Gale Crater suggests that apparently granite-like material is not from a continental crust but from a localized fractionation process, and Mars more generally has a primarily basaltic crust.  Similarly, McSween et al. [2] report in their abstract:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Surface rocks on Mars are dominantly tholeiitic basalts formed by extensive partial melting and are not highly weathered. Siliceous or calc-alkaline rocks produced by melting and/or fractional crystallization of hydrated, recycled mantle sources, and silica-poor rocks produced by limited melting of alkali-rich mantle sources, are uncommon or absent.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Cream rises to the top&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;The presence or absence of continental crust impacts crustal composition because, while ocean crust is primarily mafic, granite-rich continental crust is primarily felsic, meaning its igneous rock components are mostly minerals rich in aluminum and alkali metals.  This is in contrast with mafic rock which contains more calcium, iron and magnesium.  Felsic rock is less dense than mafic rock, and geological processes on Earth concentrated the felsic rock at the outer surface of Earth.  Calcium-rich mafic rock, which is less dense than rock containing higher amounts of magnesium and iron (which are generally mixed together in igneous-rock minerals), would also rise to the top.  Thus on Earth, calcium, aluminum and alkali metals have been enriched by forming a continental component in our crust; while on Mars these geologic processes were apparently lacking and the crust remained closer to the heavy, mafic, iron- and magnesium-rich composition of the bulk of the planet's rock.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Arya Udry, Esteban Gazel, and Harry Y. McSween Jr., &amp;quot;Formation of&#xA;Evolved Rocks at Gale Crater by Crystal Fractionation and&#xA;Implications for Mars Crustal Composition&amp;quot;, Journal of Geophysical&#xA;Research: Planets &lt;strong&gt;123&lt;/strong&gt; (2018), Issue 6, pp. 1525-1540.&#xA;&lt;a href=&quot;https://doi.org/10.1029/2018JE005602&quot; rel=&quot;nofollow noreferrer&quot;&gt;Link&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Harry Y. McSween Jr.1,G. Jeffrey Taylor, and Michael B. Wyatt,&#xA;&amp;quot;Elemental Composition of the Martian Crust&amp;quot;, &lt;em&gt;Science&lt;/em&gt; &lt;strong&gt;324&lt;/strong&gt;&#xA;(2009), Issue 5928, pp. 736-739.&#xA;&lt;a href=&quot;https://science.sciencemag.org/content/324/5928/736&quot; rel=&quot;nofollow noreferrer&quot;&gt;Link&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="2470" LastEditDate="2022-05-28T03:47:15.490" LastActivityDate="2022-05-28T03:47:15.490" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20712" PostTypeId="1" CreationDate="2021-01-21T04:18:44.713" Score="1" ViewCount="114" Body="&lt;p&gt;I'm Ocean Engineering Master Student. I have some problems with my research. When I plot the result &lt;a href=&quot;https://i.stack.imgur.com/QASZG.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QASZG.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt; it is rotated. The color blue one is land. This my script, what should I do to fix the problem?&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;    PROJECT 'tesis' 's2'&#xA;    &#xA;    $Input Data&#xA;    SET LEVEL 0.0 depmin 0.1 maxerr=1 inrhog=1 NAUT  &#xA;    MODE NONSTAT TWOD&#xA;    COORD SPHE &#xA;    &#xA;    $Domain Model&#xA;    CGRID REG 78 -15.5 0.0 83 23 415 115 &amp;amp;&#xA;        CIRCLE 36 flow=0.04 fhigh=1&#xA;    &#xA;    $Bathymetri Input-&#xA;    INPGRID BOT REGular 77.4 -15.56 0.0 20207 5949 0.004167 0.004167 &amp;amp;&#xA;        EXCEPT -9999&#xA;    READINP BOTTOM -1.0 '1.txt' 2 0 FREE &#xA;    &#xA;    $Wind Input&#xA;    INPGRID WIND REGular 78 -15.5 0.0 337 93 0.25 0.25 &amp;amp;&#xA;        NONSTAT 20190201.000000 6 HR 20190201.180000&#xA;    READINP WIND 1.00 'Feb1uv.txt' 2 0 FREE&#xA;    &#xA;    $Boundary Setting&#xA;    BOUND SHAP PM &#xA;    &#xA;    $Initial Condition&#xA;    INITIAL DEFAULT&#xA;    &#xA;    $Paramater Setting&#xA;    GEN3 KOMEN AGROW&#xA;    WCAP &#xA;    QUAD&#xA;    TRIAD&#xA;    BREAKING&#xA;    DIFFRAC&#xA;    FRICTION&#xA;    &#xA;    $ NUMERICAL CALCULATION&#xA;    &#xA;    PROP BSBT&#xA;    NUM ACCUR npnts=95. STAT mxitst=15&#xA;&#xA; &lt;span class=&quot;math-container&quot;&gt;$_________________ OUTPUT DISPLAY ______________________________________&#xA;BLOCK 'COMPGRID' NOHEAD 'coba1.mat' LAY 1 XP YP WIND HSIGN DIR PTHSIGN PTDIR OUT 20190201.000000 6 HR &#xA;$&lt;/span&gt;end&#xA;COMP NONSTAT 20190201.000000 6 HR 20190201.180000&#xA;STOP &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="21680" LastEditorUserId="2470" LastEditDate="2021-01-21T06:49:47.810" LastActivityDate="2021-01-23T22:58:19.970" Title="SWAN WAVE model: Strange result" Tags="|oceanography|wind|waves|wave-modeling|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20713" PostTypeId="2" ParentId="20673" CreationDate="2021-01-21T11:05:30.597" Score="1" Body="&lt;p&gt;Mostly temperature, leakage of CFCs(&lt;a href=&quot;https://en.wikipedia.org/wiki/Chlorofluorocarbon&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chlorofluorocarbons&lt;/a&gt;), produced for early model refrigeration units thinned the ozone layer a bit all over the world but in Antarctica, and to a lesser extent over Scandinavia, CFCs were frozen into winter snowfall rather than effecting the ozone layer equally year round. Small amounts of ozone damage regenerated reasonably quickly, I understand the reaction is self catalysing but I'm not sure of that, but the flood of CFCs evaporating with the summer thaw in colder climates overwhelmed the natural increase and thus the massive hole down south. The Arctic isn't as badly effected due to the combination of fact that much of the melting ice turns to water which absorbs much of the CFC burden, continental Antarctica sees more ablation in summer months than melting, and the fact that global air currents concentrated much of the pollutant matter south of the equator in the first place.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2021-01-21T11:05:30.597" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20715" PostTypeId="2" ParentId="12096" CreationDate="2021-01-21T23:49:14.357" Score="2" Body="&lt;p&gt;A complicating factor will be the change in density with temperature. So for this I will assume a constant density of water.&lt;/p&gt;&#xA;&lt;p&gt;As the thickness of the water layer is quite small compared to the size of Earth (given as 2.6 km by the answer to the other question) I think an approximation with a constant &lt;em&gt;g&lt;/em&gt; at any particular location should give a fairly reasonable answer.&lt;/p&gt;&#xA;&lt;p&gt;Water naturally finds its level based upon pressure. So if we have a constant pressure at the top of the surface, the pressure at the bottom must also be constant. And this should work as a reasonable approximation for any number of layers.&lt;/p&gt;&#xA;&lt;p&gt;Noting that for any column of water, the pressure increase will be given by:&lt;br&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$P=\rho \cdot g \cdot h$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Taking the values of &lt;em&gt;g&lt;/em&gt; from &lt;a href=&quot;https://en.wikipedia.org/wiki/Gravity_of_Earth#Latitude&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;At the equator, &lt;em&gt;g&lt;/em&gt;, due to Earth being an oblate spheroid and rotating is ~&lt;span class=&quot;math-container&quot;&gt;$9.78 \frac{\mathrm{m}}{\mathrm{s}^2}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;At the poles, &lt;em&gt;g&lt;/em&gt; is ~&lt;span class=&quot;math-container&quot;&gt;$9.83 \frac{\mathrm{m}}{\mathrm{s}^2}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Equating the 2 we end up with:&#xA;&lt;span class=&quot;math-container&quot;&gt;$P=\rho \cdot 9.78 \frac{\mathrm{m}}{\mathrm{s}^2} \cdot h_e=\rho \cdot 9.83 \frac{\mathrm{m}}{\mathrm{s}^2} \cdot h_p$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Factoring out common terms leaves us with:&#xA;&lt;span class=&quot;math-container&quot;&gt;$h_e = \frac{9.83}{9.78} h_p$&lt;/span&gt;&#xA;So the equator will have water that is roughly 0.5% deeper than the poles.&lt;/p&gt;&#xA;&lt;p&gt;For 2.6 km, that works out to be roughly 13 m.&lt;/p&gt;&#xA;" OwnerUserId="21381" LastEditorUserId="21381" LastEditDate="2021-01-22T03:29:32.503" LastActivityDate="2021-01-22T03:29:32.503" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20718" PostTypeId="2" ParentId="20706" CreationDate="2021-01-22T09:27:20.120" Score="4" Body="&lt;p&gt;This is a statement of the kinematic free surface boundary condition: there can be no normal flow through the boundary, only tangential flow along it. Equivalently, the normal velocity (relative to the interface) of the free surface position is the same as the velocity of the fluid.&lt;/p&gt;&#xA;&lt;p&gt;Defining the position of the free surface as&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ z = \eta(x,y,t) $$&lt;/span&gt;&#xA;then taking the material derivative&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial z}{\partial t} + &#xA;u\frac{\partial z}{\partial x} +&#xA;v\frac{\partial z}{\partial y} +&#xA;w\frac{\partial z}{\partial z} =&#xA;\frac{D\eta}{Dt} &#xA;$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Every term on the LHS besides &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial z}{\partial z}=1$&lt;/span&gt; goes to &lt;span class=&quot;math-container&quot;&gt;$0$&lt;/span&gt; due to the fact that &lt;span class=&quot;math-container&quot;&gt;$z$&lt;/span&gt; is an independent coordinate (see this &lt;a href=&quot;https://math.stackexchange.com/a/3067984&quot;&gt;answer&lt;/a&gt; for reference), leaving us with&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$w(z=\eta) = \frac{D\eta}{Dt}$$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="21649" LastEditorUserId="21649" LastEditDate="2021-01-22T14:49:56.833" LastActivityDate="2021-01-22T14:49:56.833" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20720" PostTypeId="2" ParentId="20649" CreationDate="2021-01-23T01:38:39.577" Score="1" Body="&lt;p&gt;Lagos experiences a &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_savanna_climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;tropical savanna&lt;/em&gt;&lt;/a&gt; and Miami a &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_monsoon_climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;tropical monsoon&lt;/em&gt;&lt;/a&gt; climate. Rainfall and temperature are indeed not too different in the two cities but - as their different climate classifications imply - the annual cycles as well as the underlying drivers in these respects do differ (Figs. 1,2).&lt;/p&gt;&#xA;&lt;p&gt;Although located in the Northern Hemisphere, temperature in Lagos is lowest in summer when the Intertropical Convergent Zone (ITCZ) migrates over the region and the associated cloud cover effectively blocks sunlight (&lt;a href=&quot;https://en.wikipedia.org/wiki/Geography_of_Nigeria#Temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Geography_of_Nigeria#Temperature&lt;/a&gt;). The rainfall annual cycle is again dictated by the seasonal evolution and latitudinal migrations of the ITCZ.&lt;/p&gt;&#xA;&lt;p&gt;A more typical temperature annual cycle is evident in Miami with a maximum in summer. Rainfall in Miami exhibits peaks in June and September (as in Lagos; interestingly) mostly associated with the formation of thunderstorms that are driven by large summer insolation (leading to unstable air), moisture supply, and the favorable interaction between the subtropical high and the local sea breezes (&lt;a href=&quot;https://www.weather.gov/tbw/Thunderstorm_Climatology&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.weather.gov/tbw/Thunderstorm_Climatology&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PJc49.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PJc49.png&quot; alt=&quot;Climate of Lagos, Nigeria (https://worldweather.wmo.int/en/city.html?cityId=258) &quot; /&gt;&lt;/a&gt;&#xA;&lt;em&gt;Fig. 1: Annual cycle of rainfall (bars) and daily min/max temperature (blue/red lines) in Lagos, Nigeria (&lt;a href=&quot;https://worldweather.wmo.int/en/city.html?cityId=258&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://worldweather.wmo.int/en/city.html?cityId=258&lt;/a&gt;)&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8bZ0T.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8bZ0T.png&quot; alt=&quot;Climate of Miami, USA (https://worldweather.wmo.int/en/city.html?cityId=267)&quot; /&gt;&lt;/a&gt;&#xA;&lt;em&gt;Fig. 2: As in Fig. 1, but for Miami, USA (&lt;a href=&quot;https://worldweather.wmo.int/en/city.html?cityId=267&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://worldweather.wmo.int/en/city.html?cityId=267&lt;/a&gt;)&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="21690" LastActivityDate="2021-01-23T01:38:39.577" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20724" PostTypeId="1" CreationDate="2021-01-23T23:41:31.470" Score="1" ViewCount="29" Body="&lt;p&gt;I'm Ocean Engineering Master Student. I'm not an expert in SWAN. I have some problem with it. Previously my result like rotated so I take another option to make grids using GridBuilder but SWAN doesn't work. This is my script. The error is Severe error: At least, FLOW and FHIGH or MSC must be given! I think the FLOW and FHIGH already exist. What should I do? Thanks&lt;/p&gt;&#xA;&lt;p&gt;Best Regards&#xA;Rahmadimi&lt;/p&gt;&#xA;&lt;p&gt;PROJECT 'tesis' 's2'&lt;/p&gt;&#xA;&lt;p&gt;$Input Data&#xA;SET LEVEL 0.0 depmin 0.1 maxerr=2 inrhog=1 NAUT&lt;br /&gt;&#xA;MODE NONSTAT TWOD&#xA;COORD SPHE&lt;/p&gt;&#xA;&lt;p&gt;$grid input&#xA;CGRID CURVILINEAR 114 414 EXC -9999 CIRCLE 36 flow=0.04 fhigh=1 40&#xA;READGRID COORDINATES 1 'test2.grd' 4 0 0 FREE&lt;/p&gt;&#xA;&lt;p&gt;$Bathymetri Input-&#xA;INPGRID BOTTOM CURVILINEAR 0 0 114 414 EXC -9999&#xA;READINP BOTTOM 1 'test2.bot' 4 0 FREE&lt;/p&gt;&#xA;&lt;p&gt;$Wind Input&#xA;INPGRID WIND REGular 78 -15.5 0.0 337 93 0.25 0.25 &amp;amp;&#xA;NONSTAT 20190201.000000 6 HR 20190201.180000&#xA;READINP WIND 1.00 'Feb1uv.txt' 2 0 FREE&lt;/p&gt;&#xA;&lt;p&gt;$Boundary Setting&#xA;BOUND SHAP PM&lt;/p&gt;&#xA;&lt;p&gt;$Initial Condition&#xA;INITIAL DEFAULT&lt;/p&gt;&#xA;&lt;p&gt;$Paramater Setting&#xA;GEN3 KOMEN AGROW&#xA;WCAP&#xA;QUAD&#xA;TRIAD&#xA;BREAKING&#xA;DIFFRAC&#xA;FRICTION&lt;/p&gt;&#xA;&lt;p&gt;$ NUMERICAL CALCULATION&lt;/p&gt;&#xA;&lt;p&gt;PROP BSBT&#xA;NUM ACCUR npnts=95. STAT mxitst=15&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$ _________________ OUTPUT DISPLAY ______________________________________&#xA;BLOCK 'COMPGRID' NOHEAD 'Feb19-1-1.mat' LAY 3 XP YP FRAME WIND HSIGN DIR PTHSIGN PTDIR OUT 20190201.000000 6 HR &#xA;$&lt;/span&gt;end&#xA;COMP NONSTAT 20190201.000000 6 HR 20190201.180000&#xA;STOP&lt;/p&gt;&#xA;" OwnerUserId="21680" LastActivityDate="2021-01-23T23:41:31.470" Title="SWAN doesn't run" Tags="|oceanography|wind|waves|wave-modeling|" AnswerCount="0" CommentCount="1" ClosedDate="2021-01-26T13:41:33.120" ContentLicense="CC BY-SA 4.0" />
  <row Id="20725" PostTypeId="1" AcceptedAnswerId="20726" CreationDate="2021-01-24T09:59:46.113" Score="2" ViewCount="119" Body="&lt;p&gt;From &lt;a href=&quot;https://en.wikipedia.org/wiki/Iceberg&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;Iceberg - Wikipedia&quot;&gt;Iceberg - Wikipedia&lt;/a&gt;, the closest mountain-shaped iceberg seem to be dome iceberg:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/6/61/Types_of_Icebergs.svg&quot; alt=&quot;&quot; /&gt;&#xA;Different shapes of icebergs. 1: Tabular; 2: Wedge; 3: Dome; 4: Drydock; 5: Pinnacled; 6: Blocky.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;However, dome icebergs seem to be like two mountains attached to their bases, not a single mountain one:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/3/3d/Iceberg_in_the_Arctic_with_its_underside_exposed.jpg&quot; alt=&quot;&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;Is there an iceberg that is simply gradually larger to the bottom, even when passing the water surface?&lt;/p&gt;&#xA;" OwnerUserId="4945" LastActivityDate="2021-01-25T22:25:00.043" Title="Is there a mountain-shaped iceberg?" Tags="|glaciology|glaciation|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20726" PostTypeId="2" ParentId="20725" CreationDate="2021-01-25T22:25:00.043" Score="5" Body="&lt;p&gt;Ice being less dense than water, icebergs float to the degree they displace water, with about 1/8 of their mass above the surface. Icebergs are also dynamic, melting from exposure to sunlight, warm air and water, eroding, and fracturing, and pushed by both wind and waves. (Notably the descriptions used in the Wikipedia article generally apply to the shape of that small portion of an iceberg visible above the surface, not the gross geometry of the whole berg.)&lt;/p&gt;&#xA;&lt;p&gt;Geophysicist Henry Pollack explored the potential stable positions of icebergs in &lt;a href=&quot;https://physicstoday.scitation.org/doi/10.1063/PT.3.4373&quot; rel=&quot;noreferrer&quot;&gt;a Physics Today article titled &amp;quot;Tip of the Iceberg&amp;quot;&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;When a totally submerged lower-density body is released, the buoyancy&#xA;force causes it to rise until it reaches a floating equilibrium. The&#xA;tip then rests above the surface and the root below it, with the mass&#xA;of each determined by the density contrast between the floating solid&#xA;and the surrounding fluid.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;A floating object is only stable to the extent that its center of gravity is aligned above its center of buoyancy, Pollack writes, &amp;quot;...ice cylinders floating in water will stabilize in only two orientations—with the cylindrical axis either perpendicular or parallel to the water surface;&amp;quot; With an idealized ice-like cylinder 9/10 the density of water, the mass can't be stable if it's taller than it is wide.&lt;/p&gt;&#xA;&lt;p&gt;The geometry won't be much different using an idealized cone shape -- a cylinder widening along its length -- for your mountain. It can only be short and squat,  and if it's at all unbalanced at any point in its life, it'll flip to a new stable equilibrium, on its side or upside-down.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2021-01-25T22:25:00.043" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="20728" PostTypeId="1" CreationDate="2021-01-27T02:24:56.690" Score="4" ViewCount="114" Body="&lt;p&gt;I'm not asking about the history of the line, nor am I asking about the tectonic plates underneath. If you look at the gif below, you will see that when panning very close to the earth on Google Earth, the Prime Meridian line (in yellow) seems to shift depending on where you pan. Is this a flaw in Google Earth? I would assume that the line should stay in place, like the other longitude lines.&lt;/p&gt;&#xA;&lt;p&gt;What am I missing?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rQ5P4.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://i.stack.imgur.com/rQ5P4.jpg&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;PS. Not sure if this is the correct stack exchange site for this question. Please comment if there is a better site.&lt;/p&gt;&#xA;" OwnerUserId="21713" LastActivityDate="2021-01-27T02:24:56.690" Title="Why does the Prime Meridian line shift in Google Earth when panning?" Tags="|geography|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20730" PostTypeId="2" ParentId="236" CreationDate="2021-01-28T04:18:16.270" Score="0" Body="&lt;p&gt;No not really, because the earth will be engulfed by the sun as a red giant at which point it might accrete mass or fall into the sun, still rotating at 50hrs/day... we d be talking well above 20/50 Gya.&#xA;It's alse enough time for the solar system to be disrupted by galactic events like local supernova destruction and being captured by a passing star which migh render it into multiple fragments.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2o62i.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2o62i.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2021-01-28T04:30:04.250" LastActivityDate="2021-01-28T04:30:04.250" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20731" PostTypeId="2" ParentId="20659" CreationDate="2021-01-28T06:20:39.243" Score="-1" Body="&lt;p&gt;Firstly, the simple way to calculate a length change from a volumetric expansion coefficient is to divide that coefficient by 3 to get it for length. So with a volumetric expansion coefficient of 0.0002085, you have a linear expansion coefficient of roughly 0.0000695.&#xA;Multiplying that by the average depth of 10 000 ft, you end up with a change of roughly 0.695 feet.&lt;/p&gt;&#xA;&lt;p&gt;However, there are a multitude of factors at play. The simplest is that it is the surface temperature that has risen. It will take considerable time to heat all of the ocean.&lt;/p&gt;&#xA;&lt;p&gt;Another factor is evaporation. Hotter air is capable of holding more moisture, and hotter temperatures result in a faster rate of evaporation. This means as the temperature of the air increases, you would expect more moisture to be in the air. This increase in water content of air reduces the amount in the ocean.&lt;/p&gt;&#xA;" OwnerUserId="21381" LastActivityDate="2021-01-28T06:20:39.243" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20733" PostTypeId="1" AcceptedAnswerId="22964" CreationDate="2021-01-28T09:28:30.147" Score="7" ViewCount="3776" Body="&lt;p&gt;Can we convert latent heat flux to actual evapotranspiration using simply this conversion rate: 2.45 MJ m&lt;sup&gt;-2&lt;/sup&gt; day&lt;sup&gt;-1&lt;/sup&gt; = 1 mm day&lt;sup&gt;-1&lt;/sup&gt; (Allen, 1998)?&lt;/p&gt;&#xA;" OwnerUserId="21719" LastEditorUserId="24481" LastEditDate="2021-10-11T07:54:44.330" LastActivityDate="2021-10-11T09:27:29.790" Title="FLUXNET15 - how to convert latent heat flux to actual evapotranspiration?" Tags="|evaporation|energy-balance|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20734" PostTypeId="2" ParentId="13265" CreationDate="2021-01-28T09:40:40.587" Score="7" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;How can the air in the Earth's shadow scatter blue light if it doesn't get any direct illumination, and any indirect illumination getting back there should be VERY depleted in blue (i.e. mostly red light)?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You're completely right. If you simulate light scattering only, you'll get exactly this result: a sandy-colored sky, with a bit redder belt of Venus, and a gray shadow of the Earth:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3FOmY.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3FOmY.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But our stratosphere contains a small amount of ozone, which absorbs in the orange region of the spectrum in what is known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Chappuis_absorption&quot; rel=&quot;noreferrer&quot;&gt;Chappuis band&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/RrEhx.png&quot; alt=&quot;Chappuis band spectrum&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;At daytime the solar light propagates at a small angle to the atmosphere, crossing a low amount of ozone, so the color of the sky is not affected (see also the question at Chemistry.SE: &lt;a href=&quot;https://chemistry.stackexchange.com/q/111389/2133&quot;&gt;What exact color does ozone gas have?&lt;/a&gt;). But at twilight the sunlight goes through a large layer of atmosphere horizontally, thus the Chappuis absorption is very prominent.&lt;/p&gt;&#xA;&lt;p&gt;The same simulation as above, but with ozone included (and with a bit higher exposure), will look like this:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bdp5H.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bdp5H.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Why is the shadow more blue (less orange) than the other parts of the sky? It's because in the shadow, there's no light from the single scattering: a ray from the Sun must be scattered at least twice to get to the earthly observer. This makes the Rayleigh scattering multiplier &lt;span class=&quot;math-container&quot;&gt;$\propto\lambda^{-4}$&lt;/span&gt; apply twice, thus increasing the blue component of the inscattered light relatively to the red component. OTOH, the other atmosphere parts being not in the shadow, means that they do have contribution from the light scattered once, which has only a first power of this multiplier.&lt;/p&gt;&#xA;" OwnerUserId="12360" LastActivityDate="2021-01-28T09:40:40.587" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="20735" PostTypeId="1" CreationDate="2021-01-29T17:37:05.830" Score="6" ViewCount="112" Body="&lt;p&gt;I can't think of a possible explanation, there's no volcanic activity in the area, and it gets destroyed every time a hurricane passes through. How did it get there?&lt;/p&gt;&#xA;" OwnerUserId="21729" LastActivityDate="2021-02-04T19:24:57.150" Title="How do long, thin, island chains such as North Carolina's outer banks, form?" Tags="|geology|oceanography|islands|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20736" PostTypeId="2" ParentId="20684" CreationDate="2021-01-29T18:35:45.170" Score="3" Body="&lt;p&gt;Theoretically? Maybe! Practically? No. Identifying the general quarry site by comparing lithology is often possible. It might be possible to identify a block as coming from a particular level in a quarry by detailed characterisation of micro-fossil assemblages. Geochemical analyses could assist. However the practical problems are almost certainly insurmountable:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The limestone rocks used in the pyramids were deposited in a marine reef environment, so deposition rates could be quite high. This means that with small age differences between the top and bottom there may be negligible variation in the micro-fossils.&lt;/li&gt;&#xA;&lt;li&gt;The parts of the quarry from which rock was taken are, by definition, not there to be sampled. You would have to take your comparison core from the edge of the quarry and you would presumably be looking at the stratigraphy of the layer on the outside of the pyramid which may have come from the centre of the quarry. Reef limestones can change their characteristics significantly over short distances.&lt;/li&gt;&#xA;&lt;li&gt;The exposed limestone blocks will have been altered by weathering - so would probably need destructive sampling by coring to gather material for comparison.&lt;/li&gt;&#xA;&lt;li&gt;As an analogy, matching individual blocks to layers in a quarry would be like trying to match sawn wood to individual tree stumps in a forest. Conceptually possible, but would take an awful lot of work and even more luck.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2021-01-29T18:35:45.170" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20739" PostTypeId="2" ParentId="13654" CreationDate="2021-01-30T18:24:33.793" Score="1" Body="&lt;p&gt;We have TONS OF water. question is ..&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Is it potable&lt;/li&gt;&#xA;&lt;li&gt;does withdraw rate of water capable of being sustained by periodic recharge (Rain/percolation)&#xA;Because storage capacity&lt;/li&gt;&#xA;&lt;li&gt;How much water do you need/society&#xA;Industry/agriculture are the largest water users...... human personal needs (drinking/bathing) surprisingly low.&#xA;Africa, has been predicted to have 75 to 250 million inhabitants lacking access to fresh water and where available mostly is unsuitable to drink without boiling which is why waterborne diseases are so ubiquitous... In the US diarrhea is an annoyance, in Africa diarrhea kills a million a year.&#xA;Another aspect is infrastructure that makes water safe to access (plumbing, home connecting)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-01-30T18:24:33.793" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20740" PostTypeId="1" CreationDate="2021-01-30T19:30:46.657" Score="4" ViewCount="39" Body="&lt;p&gt;I am currently working on a set of geochemical data representing calc-alkaline igneous intrusions from central Canada.  The samples were analyzed in ~2013-2014.  These samples have been tested for LOI wt%, but not H&lt;sub&gt;2&lt;/sub&gt;O, CO&lt;sub&gt;2&lt;/sub&gt;...etc.  Historical sampling from the same area representing the same suite of rocks (but different sample locations) have results for H&lt;sub&gt;2&lt;/sub&gt;O and CO&lt;sub&gt;2&lt;/sub&gt; wt%.  I need H&lt;sub&gt;2&lt;/sub&gt;O wt% values for my samples in order to complete a calculation for viscosity of the intrusions, but I won't be doing any more testing.  Am I able to estimate H&lt;sub&gt;2&lt;/sub&gt;O in my samples using the historical data, and if so, how would I go about doing that?  Also, how would I correct for (if possible) the difference in quality of the measurements due to more advanced and accurate/precise instrumentation?&lt;/p&gt;&#xA;" OwnerUserId="21733" LastEditorUserId="2470" LastEditDate="2022-07-03T23:02:48.300" LastActivityDate="2022-07-03T23:02:48.300" Title="Calculating/estimating volatiles based on other representative samples" Tags="|geochemistry|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20743" PostTypeId="1" AcceptedAnswerId="20745" CreationDate="2021-01-31T17:20:55.547" Score="1" ViewCount="907" Body="&lt;p&gt;Not sure if this is the right stack for this but:&lt;/p&gt;&#xA;&lt;p&gt;I have been arguing with friends on overpopulation, several are convinced that Earth cannot sustain the current population.  Without getting into all of the ways that we are destroying various ecosystems and polluting, I believe that if we were actively working to optimize the environment and how we use resources, Earth could easily handle many, &lt;em&gt;many&lt;/em&gt; more humans.&lt;/p&gt;&#xA;&lt;p&gt;Such as renewable energy, reducing waste, committing to reversing desertification, and so much more.  But regardless of the behaviors we specifically change, looking at the raw chemistry of the planet, i.e. how much water, oxygen, carbon, plant life, and so on, there is some maximum amount of humans that can live healthy lives.&lt;/p&gt;&#xA;" OwnerUserId="21738" LastActivityDate="2021-02-06T01:43:55.520" Title="Is the maximum human population carrying capacity of Earth higher or lower than the current total human population?" Tags="|environmental-protection|human-influence|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20745" PostTypeId="2" ParentId="20743" CreationDate="2021-02-01T11:55:29.477" Score="4" Body="&lt;p&gt;The FAO estimate that we use 11% of the Earth's surface area for agriculture,  and that that represents approximately a third of the land that 'could' be used (&lt;a href=&quot;http://www.fao.org/3/y4252e/y4252e06.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.fao.org/3/y4252e/y4252e06.htm&lt;/a&gt;). If we accept that current agricultural production is at a level that allows the current population to live healthy lives that implies that we could triple our population and not starve.&lt;/p&gt;&#xA;&lt;p&gt;In this very simplistic view I am ignoring the very real questions of inequity in distribution, what constitutes 'healthy' and the potential of changing efficiency in agriculture or transitioning populations away from expensive meat based diets.&lt;/p&gt;&#xA;&lt;p&gt;However, and it's a really big however, you couldn't make that sort of increase in the area of globe used for agriculture without destroying natural ecosystems, and it's arguable that already much of global agriculture is unsustainable in it's present form, as aquifers are overexploited and soil quality degrades.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastEditorUserId="21672" LastEditDate="2021-02-03T17:55:22.177" LastActivityDate="2021-02-03T17:55:22.177" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20746" PostTypeId="2" ParentId="20740" CreationDate="2021-02-01T13:01:04.297" Score="3" Body="&lt;p&gt;If you are sure that the samples for which you have H&lt;sub&gt;2&lt;/sub&gt;O data are from the same intrusion than yours, then I don't see a problem for using these values for viscosity modelling, as long as it is clearly mentioned in the paper. After all, a sample is supposed to &lt;em&gt;representative&lt;/em&gt; of the rock unit, and science is done by standing on the shoulders of giants!&lt;/p&gt;&#xA;&lt;p&gt;If you have several historical samples with different H&lt;sub&gt;2&lt;/sub&gt;O contents, this gives you a range of water contents. Do you intend to use a model like &lt;a href=&quot;https://doi.org/10.1016/j.epsl.2008.03.038&quot; rel=&quot;nofollow noreferrer&quot;&gt;Giordano et al. (2008)&lt;/a&gt; ? If so, you also need a temperature estimate, which you may have by geothermometry. These temperature estimates have an uncertainty, see &lt;a href=&quot;https://doi.org/10.2138/rmg.2008.69.3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Putirka (2008)&lt;/a&gt; for a review. For example, if you use the two-feldspar thermometer, it gives you &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; to &lt;span class=&quot;math-container&quot;&gt;$\pm$&lt;/span&gt;30 °C.&lt;/p&gt;&#xA;&lt;p&gt;So, what you could do is to model two scenarios: one &amp;quot;cool and dry&amp;quot;, with the lowest &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; and H&lt;sub&gt;2&lt;/sub&gt;O content, which gives you the highest viscosity; and one &amp;quot;hot and wet&amp;quot;, with the highest &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; and H&lt;sub&gt;2&lt;/sub&gt;O content, which gives you the lowest viscosity. This way you can be quite confident that the viscosity was somewhere between these two values. Usually a &lt;span class=&quot;math-container&quot;&gt;$\pm$&lt;/span&gt;30 °C interval will change your result by half a log unit, and a &lt;span class=&quot;math-container&quot;&gt;$\pm$&lt;/span&gt;0.2 wt% H&lt;sub&gt;2&lt;/sub&gt;O interval will change it by one log unit, so you'd get something like &lt;span class=&quot;math-container&quot;&gt;$\log \eta = X \pm 0.75$&lt;/span&gt; Pa s, which is not that bad.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="2958" LastEditDate="2022-07-03T13:07:09.907" LastActivityDate="2022-07-03T13:07:09.907" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20747" PostTypeId="1" CreationDate="2021-02-01T17:32:49.667" Score="1" ViewCount="40" Body="&lt;p&gt;I am a P.h.D student working on effects of Evaporation duct on radio propagation. Pandemic is successfully stopping me from obtaining my own measurements for my thesis, but I would like to compare the model I am working on with some real-world data. What I require is data for Atmospheric Pressure, temperature and relative humidity measured in one location at different altitudes. The University of Wyoming has published such a set of data (Available &lt;a href=&quot;http://weather.uwyo.edu/upperair/sounding.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/BtGcm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BtGcm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;While their data are perfectly fine, the fast ascend in altitudes where data are measured at is not ideal for me. What I require are the heights between 0 and 200 metres. Perhaps any of you know of a place where such data can be found?&lt;/p&gt;&#xA;" OwnerUserId="17607" LastActivityDate="2021-02-01T17:32:49.667" Title="A database with measurments of meteorological parameters at various altitudes" Tags="|meteorology|open-data|database|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20748" PostTypeId="1" AcceptedAnswerId="20750" CreationDate="2021-02-02T02:14:30.840" Score="1" ViewCount="316" Body="&lt;p&gt;The ocean has some of the deepest locations on earth, typically caused by subduction zones. Why are there no subduction trenches on land?&lt;/p&gt;&#xA;" OwnerUserId="21749" LastActivityDate="2021-02-03T23:32:49.500" Title="Why are there no subduction trenches on continental land?" Tags="|plate-tectonics|subduction|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20749" PostTypeId="2" ParentId="20743" CreationDate="2021-02-02T07:06:25.353" Score="-2" Body="&lt;h2&gt;The population is degradatively and unsustainably overconsuming&lt;/h2&gt;&#xA;&lt;p&gt;Everyone truthful agrees the above statement.&lt;/p&gt;&#xA;&lt;p&gt;The keywords are &lt;em&gt;degradatively&lt;/em&gt; and &lt;em&gt;destructively&lt;/em&gt; for people and crowds. Few people deny that.&lt;/p&gt;&#xA;&lt;p&gt;The seas are already being overfished with many species collapsed to low volume stocks, the land is intensely overfarmed with cocktails of chemicals and pesticides, the rivers near industrial farms also absorb nitrogen and pesticides, the sky is destabilized, deforestation is impissible to control. Dolphins tigers rhinos birds insects etc are now extinct, and 80 percent of the world population want to increase resource consumption to 500% of current levels, i.e. young Africans want playstations, SUVs... in a reasonable compromise we cant responsibly manage current overpopulation, its very poor on average, so from a responsible point of view, having children are being born in poor megacities, uneducated and thirsty to have a house garden and car. Its destructively overpopulated without and end to the degradation predicted.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2021-02-03T07:27:24.390" LastActivityDate="2021-02-03T07:27:24.390" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20750" PostTypeId="2" ParentId="20748" CreationDate="2021-02-02T15:10:36.703" Score="5" Body="&lt;p&gt;Continental crust is thick and relatively buoyant.  Ocean crust is much thinner, and relatively dense.&lt;/p&gt;&#xA;&lt;p&gt;Hence ocean crust &amp;quot;goes down&amp;quot; more easily, and the density can even help pull the ocean slab due to metamorphism.&lt;/p&gt;&#xA;&lt;p&gt;In contrast, the continents are almost like floating scum which won't go down! When they collide, you get faulting and folding, and the building up of very thick continental crust. Tibet is the best example today. Yes the Tibetan Plateau is high, but the crust is over 100km thick! (think of an iceberg, most of it is below)&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2021-02-02T15:10:36.703" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20751" PostTypeId="1" CreationDate="2021-02-03T18:30:14.943" Score="4" ViewCount="122" Body="&lt;p&gt;I am seeing two different formulas for the mixing ratio, which differ by a factor 1000. To be more specific:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$w = 0.622 \cdot (e/p)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$w = 1000 \cdot 0.622 \cdot (e/p)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$e$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; are the water vapour pressure and the atmospheric pressure, respectively.&lt;/p&gt;&#xA;&lt;p&gt;I assume the factor 1000 has to do with the fact that the mixing ratio is theoretically a ratio of masses, so probably the numerator can be expressed in grams and has to be converted to kilograms, but I'm confused because I don't see masses in these formulas.&lt;/p&gt;&#xA;&lt;p&gt;What's the difference between the two ?&lt;/p&gt;&#xA;" OwnerUserId="20566" LastEditorUserId="20566" LastEditDate="2021-02-04T08:54:11.620" LastActivityDate="2021-02-04T08:54:11.620" Title="Factor 1000 in mixing ratio formula" Tags="|atmosphere|geophysics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20752" PostTypeId="2" ParentId="20751" CreationDate="2021-02-03T18:54:13.330" Score="5" Body="&lt;p&gt;The factor of 1000 may be related to the expected units. The mass 'units' can be found in the derivation.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.e-education.psu.edu/meteo300/node/519#:%7E:text=The%20water%20vapor%20mixing%20ratio,to%20within%20a%20few%20percent.&quot; rel=&quot;noreferrer&quot;&gt;The full derivation&lt;/a&gt; of mixing ratio goes like this&#xA;&lt;span class=&quot;math-container&quot;&gt;$$w=\epsilon\frac{e}{P}$$&lt;/span&gt;&#xA;since, by the ideal gas law,&#xA;&lt;span class=&quot;math-container&quot;&gt;$$e=\rho_vR_vT$$&lt;/span&gt;&#xA;and&#xA;&lt;span class=&quot;math-container&quot;&gt;$$P_d=\rho_dR_dT$$&lt;/span&gt;&#xA;then the mixing ratio is expressed as&#xA;&lt;span class=&quot;math-container&quot;&gt;$$w=\epsilon\frac{\rho_vR_vT}{\rho_dR_dT}=\epsilon\frac{\rho_vR_v}{\rho_dR_d}$$&lt;/span&gt;&#xA;Since &lt;span class=&quot;math-container&quot;&gt;$\epsilon=\frac{R_d}{R_v}=0.622$&lt;/span&gt; (see above hyperlink),&#xA;&lt;span class=&quot;math-container&quot;&gt;$$w=\frac{\rho_v}{\rho_d}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;To return back to the question 'what is the difference between your two equations?' The units reported are &lt;span class=&quot;math-container&quot;&gt;$g/g$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$g/kg$&lt;/span&gt; for the first and second equations, respectively.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-02-03T18:54:13.330" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20753" PostTypeId="2" ParentId="20748" CreationDate="2021-02-03T23:32:49.500" Score="4" Body="&lt;p&gt;As mentioned in another answer:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Continental crust is thick and relatively buoyant. Ocean crust is much thinner, and relatively dense.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Let's look at a simulation of what might happen. Here's a figure from &amp;quot;&lt;a href=&quot;https://doi.org/10.1016/j.epsl.2010.11.035&quot; rel=&quot;nofollow noreferrer&quot;&gt;Continental collision and slab break-off: A comparison of 3-D numerical models with observations&lt;/a&gt;&amp;quot;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zuUtQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zuUtQ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Let's look at this in detail.&lt;/p&gt;&#xA;&lt;p&gt;You start by having a lithospheric plate consisting of oceanic and continental crust, going to the right, and forming a subduction zone under another lithosphere plate carrying continental crust:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QJmZ5.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QJmZ5.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Then the oceanic crust keeps going under into the mantle, eventually reaching a stage where both continental crusts are now in contact:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HxdjR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HxdjR.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Finally, the oceanic crust tears or breaks off the continental crust part, and sinks into the mantle, with the surrounding asthenospheric mantle filling up the space. There's no dense oceanic crust to pull everything down to form a trench now, so instead you have mountain ranges and the two plates are amalgamated.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-02-03T23:32:49.500" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20754" PostTypeId="2" ParentId="20740" CreationDate="2021-02-03T23:45:42.250" Score="2" Body="&lt;p&gt;There are several problems with what you're trying to do.&lt;/p&gt;&#xA;&lt;p&gt;First, you are looking at the H&lt;sub&gt;2&lt;/sub&gt;O and CO&lt;sub&gt;2&lt;/sub&gt; contents of the rock as they are &lt;em&gt;today&lt;/em&gt;. It is ignoring the fact that H&lt;sub&gt;2&lt;/sub&gt;O and CO&lt;sub&gt;2&lt;/sub&gt; &lt;em&gt;are&lt;/em&gt; lost during rising and cooling of the magma. They can also be gained during subsolidus alteration, which I suspect happened in your case because the solubility of CO&lt;sub&gt;2&lt;/sub&gt; in granitic magma is extremely low, and it should not contain any carbonate minerals. Therefore, late addition of alteration minerals such as calcite would change the values.&lt;/p&gt;&#xA;&lt;p&gt;Second, the viscosity depends on the ratio between the crystal and melt load in the magma mush. Figuring out what was solid and what was liquid and at what stage, after it has all solidified, isn't easy. What if your H&lt;sub&gt;2&lt;/sub&gt;O was all in wet amphibole phenocrysts? Or was it all in the melt? These are things you need to take into consideration.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-02-03T23:45:42.250" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20755" PostTypeId="2" ParentId="20735" CreationDate="2021-02-04T19:24:57.150" Score="3" Body="&lt;p&gt;The outer banks are, literally, a textbook example of what are known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Barrier_island&quot; rel=&quot;nofollow noreferrer&quot;&gt;Barrier Islands&lt;/a&gt;. They are thought to be formed through interactions between sediment undergoing longshore drift, coastal currents and seabed irregularities, but to spite a number of theories being put forward since the 19th Century we really don't understand their formation.&lt;/p&gt;&#xA;&lt;p&gt;We do know that their ongoing behaviour makes them analogous to underwater sand dune systems in that:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;the material in them is constantly on the move.&lt;/li&gt;&#xA;&lt;li&gt;their form is controlled by the prevailing conditions.&lt;/li&gt;&#xA;&lt;li&gt;they offer a degree of protection to the landscape on their inland side.&#xA;and&lt;/li&gt;&#xA;&lt;li&gt;they are vulnerable to drastic alteration during extreme events such as storms or tsunamis.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2021-02-04T19:24:57.150" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20756" PostTypeId="2" ParentId="18305" CreationDate="2021-02-05T04:01:33.567" Score="1" Body="&lt;p&gt;I don't know how to get it in JSON format, but you can probably write a simple webscraping script for &lt;a href=&quot;https://www.wunderground.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weather Underground&lt;/a&gt;. For example, if you want to make a calendar for your best friend in Greenland, you can use &lt;a href=&quot;https://www.wunderground.com/history/monthly/gl/kangerlussuaq/BGSF&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.wunderground.com/history/monthly/gl/kangerlussuaq/BGSF&lt;/a&gt;. Or, in HTML terms, &lt;a href=&quot;https://www.wunderground.com/history/monthly/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.wunderground.com/history/monthly/&lt;/a&gt;&amp;lt;country&amp;gt;/&amp;lt;city&amp;gt;/&amp;lt;ICAO&amp;gt;/. Of course, I would recommend going to the Weather underground website and exploring a bit to avoid unexpected behavior.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-02-05T04:01:33.567" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20757" PostTypeId="1" CreationDate="2021-02-05T14:24:55.860" Score="4" ViewCount="2286" Body="&lt;p&gt;I know Earth once had this amount in the past, but if we got the former atmosphere with around 20% of CO&lt;sub&gt;2&lt;/sub&gt;, how much the temperature will rise? assuming the atmosphere is still dominated by 78% nitrogen and 2% of other gasses.&lt;/p&gt;&#xA;&lt;p&gt;Would it go runaway greenhouse effect?&lt;/p&gt;&#xA;&lt;p&gt;And what about if Earth has the same atmosphere that we have today but with 0% CO&lt;sub&gt;2&lt;/sub&gt;, how cold it will be? assuming other greenhouse gasses aren't changed and still affecting the planet.&lt;/p&gt;&#xA;&lt;p&gt;And I know that neither the temperature nor the atmosphere will be friendly, at least not to us.&lt;/p&gt;&#xA;&lt;p&gt;I don't want to know what will happen to life or if the Earth will still livable because it's obvious. (Edited)&lt;/p&gt;&#xA;" OwnerUserId="21766" LastEditorUserId="2470" LastEditDate="2021-02-13T06:27:22.880" LastActivityDate="2022-09-19T21:02:21.053" Title="How hot the earth will be if we have 20% CO2 in the atmosphere instead of ~0.04? and how cold would it be if doesn't have any CO2?" Tags="|atmosphere|co2|greenhouse-gases|" AnswerCount="5" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20758" PostTypeId="1" CreationDate="2021-02-05T16:33:50.257" Score="5" ViewCount="694" Body="&lt;p&gt;What does the term &amp;quot;topology&amp;quot; mean in geological sciences? Is there an agreed upon distinction between the two terms &amp;quot;topography&amp;quot; and &amp;quot;topology&amp;quot;?&lt;/p&gt;&#xA;&lt;p&gt;When trying to answer this question, I came across the article &amp;quot;On the topology of topography: a review&amp;quot; by Keith Clarke and Boleslo E. Romero, however from reading the abstract of this article it seems like they use the mathematical definition of topology. On the other hand, in &lt;a href=&quot;https://earthscience.stackexchange.com/a/2641/21767&quot;&gt;this&lt;/a&gt; answer, the term &amp;quot;topology&amp;quot; seems to be used as a synonym to topography.&lt;/p&gt;&#xA;" OwnerUserId="21767" LastActivityDate="2021-03-08T09:03:10.233" Title="What does the term &quot;topology&quot; mean in geology?" Tags="|terminology|topography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20759" PostTypeId="2" ParentId="20743" CreationDate="2021-02-06T01:43:55.520" Score="-1" Body="&lt;p&gt;Welcome to Earth Science SE! I actually think this belongs on the &lt;a href=&quot;https://sustainability.stackexchange.com/&quot;&gt;Sustainability SE&lt;/a&gt; more than the Earth Science SE. But, in the spirit of giving an answer, I'll try to answer it (probably more my opinion, but I have sources and reasoning to back it up).&lt;/p&gt;&#xA;&lt;p&gt;I think it really depends on what you mean by capacity. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Malthusianism&quot; rel=&quot;nofollow noreferrer&quot;&gt;discredited Malthusian ideas&lt;/a&gt; still have many proponents (which may make my answer a bit unpopular). Even if you think that it is not a discredited idea, &lt;a href=&quot;https://www.vox.com/the-big-idea/2017/12/12/16766872/overpopulation-exaggerated-concern-climate-change-world-population&quot; rel=&quot;nofollow noreferrer&quot;&gt;it is still a bit overstated.&lt;/a&gt; However, idealists from all over the political spectrum (from &lt;a href=&quot;https://mises.org/library/malthus-and-assault-population&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mises&lt;/a&gt; to &lt;a href=&quot;https://journals.sagepub.com/doi/abs/10.1177/0921810698114010&quot; rel=&quot;nofollow noreferrer&quot;&gt;Marx&lt;/a&gt;) disagree with Malthus. Still, a lot of ideas stem from the idea of &lt;a href=&quot;https://en.wikipedia.org/wiki/Human_overpopulation&quot; rel=&quot;nofollow noreferrer&quot;&gt;overpopulation&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Let's think about what would cause a drastic population collapse? The dystopians, when they talk about capacity, often think about the amount of food. But the reality is that &lt;a href=&quot;https://theconversation.com/famines-in-the-21st-century-its-not-for-lack-of-food-73587&quot; rel=&quot;nofollow noreferrer&quot;&gt;most famines are human generated&lt;/a&gt; (by economics, war, etc.), though climate does have an impact. &lt;a href=&quot;https://www.bloomberg.com/news/articles/2020-06-25/a-fifth-of-food-output-is-wasted-in-famine-threatened-venezuela&quot; rel=&quot;nofollow noreferrer&quot;&gt;A recent example of a modern famine is Venezuela, where inflation and price controls have made food unpurchaseable&lt;/a&gt;. Barring desertification (caused by changes in the Hadley cell), war and &lt;a href=&quot;https://www.history.com/news/ukrainian-famine-stalin&quot; rel=&quot;nofollow noreferrer&quot;&gt;political/economic factors&lt;/a&gt;, the food supply generally doesn't collapse all at once. Even when it does (such as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Dust_Bowl&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dust Bowl&lt;/a&gt;, where &lt;a href=&quot;https://www.quora.com/Did-7-million-Americans-starve-to-death-during-the-Great-Depression#:%7E:text=It%27s%20possible%20that%207%20million,being%20added%20to%20the%20population.&quot; rel=&quot;nofollow noreferrer&quot;&gt;few died directly from starvation&lt;/a&gt;, but from the dust), people often resort to other food sources.&lt;/p&gt;&#xA;&lt;p&gt;One of the common assumptions for Malthusianism is that humans are a peaceful lot. &lt;a href=&quot;https://en.wikipedia.org/wiki/War&quot; rel=&quot;nofollow noreferrer&quot;&gt;We are not&lt;/a&gt;. This creates a negative feedback mechanism. &lt;a href=&quot;https://ourworldindata.org/grapher/battle-related-deaths-in-state-based-conflicts-since-1946&quot; rel=&quot;nofollow noreferrer&quot;&gt;Until 1945&lt;/a&gt;, the &lt;a href=&quot;https://ourworldindata.org/war-and-peace&quot; rel=&quot;nofollow noreferrer&quot;&gt;number of deaths from wars was increasing,&lt;/a&gt; which &lt;a href=&quot;https://ourworldindata.org/grapher/world-population-1750-2015-and-un-projection-until-2100?time=1900..2100&quot; rel=&quot;nofollow noreferrer&quot;&gt;I think is part of the reason the population has exploded&lt;/a&gt; (granted, I will admit I am not an expert on such matters).&lt;/p&gt;&#xA;&lt;p&gt;But let's for a second, consider 'what if they are right?' Then it becomes a utilitarian problem. How would they choose to solve it? &lt;a href=&quot;https://www.imdb.com/title/tt4154756/&quot; rel=&quot;nofollow noreferrer&quot;&gt;A movie&lt;/a&gt; pondered the solution to be effective genocide. &lt;a href=&quot;http://www.spunk.org/texts/places/germany/sp001630/peter.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;But such thinking could justify actual genocide&lt;/a&gt;, and &lt;a href=&quot;https://www.jstor.org/stable/4048133?seq=1#metadata_info_tab_contents&quot; rel=&quot;nofollow noreferrer&quot;&gt;it has been entwined as a a motivation for eugenics.&lt;/a&gt; Even if the genocide isn't intentional, &lt;a href=&quot;https://en.wikipedia.org/wiki/Cambodian_genocide&quot; rel=&quot;nofollow noreferrer&quot;&gt;the force required for collective action to convert to an agrarian society can be catastrophic in its own right&lt;/a&gt;. Perhaps the biggest danger to the hypothesized 'capacity' is the risks associated with nuclear technology, since it has been shown to &lt;a href=&quot;https://www.nationalgeographic.com/culture/topics/reference/chernobyl-disaster/&quot; rel=&quot;nofollow noreferrer&quot;&gt;render areas uninhabitable for millennia&lt;/a&gt;, though &lt;a href=&quot;https://www.ucsusa.org/energy/nuclear-power&quot; rel=&quot;nofollow noreferrer&quot;&gt;some argue that it is necessary in order to prevent Malthusian collapse&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;And perhaps the biggest piece of evidence (for me) is &lt;a href=&quot;https://ourworldindata.org/urbanization#:%7E:text=Urbanization%20is%20a%20trend%20unique,areas%20as%20they%20become%20richer.&quot; rel=&quot;nofollow noreferrer&quot;&gt;the increase in urbanization&lt;/a&gt; and &lt;a href=&quot;https://www.cnbc.com/2019/04/11/census-of-agriculture-shows-continued-decline-in-number-of-us-farms.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;the decrease in agriculture&lt;/a&gt;, despite &lt;a href=&quot;https://www.nbcnews.com/news/us-news/covid-19-crisis-heaps-pressure-nation-s-food-banks-n1178731&quot; rel=&quot;nofollow noreferrer&quot;&gt;claims of excess food demand&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-02-06T01:43:55.520" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20760" PostTypeId="1" AcceptedAnswerId="20768" CreationDate="2021-02-06T07:57:13.953" Score="1" ViewCount="138" Body="&lt;p&gt;I would like to know how the resolution of a Numerical Weather Prediction model conceptually works.&lt;/p&gt;&#xA;&lt;p&gt;i.e.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Global Forecast System's forecasts with 0.5° horizontal spatial resolution&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;NCEP’s reforecast is based on the Global Ensemble Forecast System (GEFS), which has horizontal grid increments of approximately 1°.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;Are these two sentences talking about the same thing? In this case, GFS has more resolution, doesn't it?&lt;/p&gt;&#xA;" OwnerUserId="17200" LastActivityDate="2021-02-07T14:02:59.537" Title="How spatial resolution of a NWP model works?" Tags="|atmosphere|models|nwp|gfs|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20761" PostTypeId="2" ParentId="20758" CreationDate="2021-02-06T08:55:02.647" Score="2" Body="&lt;p&gt;Topology is a study of deformable shapes and connectivity. Topography is a study of more or less non-deformable shapes. A coffee cup that has an intact handle and a donut with a hole in the middle are equivalent shapes topologically, but obviously are not equivalent shapes topographically.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2021-02-06T08:55:02.647" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20762" PostTypeId="2" ParentId="20757" CreationDate="2021-02-06T09:33:24.857" Score="2" Body="&lt;p&gt;The concentration of CO&lt;sub&gt;2&lt;/sub&gt; in the Earth's atmosphere has remained less than 1% in the past 470 million years when land plants first appeared--long before mammals, and long before humans graced the earth.&lt;/p&gt;&#xA;&lt;p&gt;If we are talking about having a biosphere comparable to the one we know, we need to be talking about CO&lt;sub&gt;2&lt;/sub&gt; and global average temperatures that are comparable to levels during the relatively stable Holocene epoch of the past 11,000+ years.  Those are the conditions that support life, with the current overshoot beyond 350 ppm being brief (in terms of geological time).&lt;/p&gt;&#xA;&lt;p&gt;As for 0% CO&lt;sub&gt;2&lt;/sub&gt; concentration in the Earth's atmosphere, that would remove warming that essential for life on the planet. The goal is to have CO&lt;sub&gt;2&lt;/sub&gt; levels that are stable and also at a level which provides the warming for which life in the biosphere is accustomed to--which is less than 350 and probably even less than 325 ppm.  An accepted scientific paper is: &lt;a href=&quot;https://arxiv.org/pdf/0804.1126.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Target Atmospheric CO&lt;sub&gt;2&lt;/sub&gt;: Where should humanity aim?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This discussion should also switch from the concentration of CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere to global emissions from a few human activities (roughly 90% being combustion of fossil fuels). The question to ask is how much do those human emissions need to change for the current annual increases in CO&lt;sub&gt;2&lt;/sub&gt; concentrations to stop rising?  They need to return to emission levels that were essentially zero as they were prior to the Industrial Revolution.  That is when natural global emissions and absorption (aka sinks) cancelled one another out to keep levels stable.  However, cutting global human CO&lt;sub&gt;2&lt;/sub&gt; emissions by half (or let's say 60% to be safe) will stop the rise in CO&lt;sub&gt;2&lt;/sub&gt; levels for a few years.  If cuts do not go further within the decade toward 100%, CO&lt;sub&gt;2&lt;/sub&gt; levels in the atmosphere will start to rise again.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://archive.ipcc.ch/publications_and_data/ar4/wg1/en/faq-10-3.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reference: IPCC AR4 FAQ 10.3&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21769" LastEditorDisplayName="user20559" LastEditDate="2021-10-11T12:30:43.077" LastActivityDate="2021-10-11T12:30:43.077" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20763" PostTypeId="1" CreationDate="2021-02-06T14:45:53.790" Score="1" ViewCount="25" Body="&lt;p&gt;I am going to search  and finding some subsoil data, (vanGenuchten Parameters, specific storage, Hydraulic conductivity, porosity, Manning coefficient and humidity of root zone) I have no idea about it and want to know if there any sites about this data that one can downloaded them? is there any other way or guide? maybe someone have same problem like me and know about tips that are helping.&#xA;Thanks a lot&lt;/p&gt;&#xA;" OwnerUserId="21770" LastActivityDate="2021-02-07T14:14:01.353" Title="sub soil data finding" Tags="|soil|soil-science|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20764" PostTypeId="2" ParentId="20757" CreationDate="2021-02-06T20:08:02.860" Score="2" Body="&lt;p&gt;There are other greenhouse gasses besides carbon dioxide (in particular water vapor) but in order to give a definite answer, let's pretend the atmosphere is completely free of them.  In this case, it's easy to calculate the average temperature of the earth by holding the incoming shortwave heat flux at its present value and assuming that it is balanced by outgoing blackbody radiation from the surface.&lt;/p&gt;&#xA;&lt;p&gt;Similarly, rather than deal with your 20% carbon dioxide atmosphere explicitly, let's just say the atmosphere provides a &amp;quot;perfect&amp;quot; single-layer greenhouse blanket: an isothermal one that allows shortwave radiation through in the same way the existent one does, but absorbs all the outgoing longwave radiation (I don't think anywhere close to 20% concentration of carbon dioxide would be required to approach this limit). This greenhouse blanket reaches a temperature such that it radiates the same amount of heat to space as is coming in from the sun.  Since it radiates equally upward and downward (and we assume all of the downward longwave radiation is absorbed), this means the total energy absorbed (and therefore, in equilibrium, radiated) at the surface is doubled relative to what it would be with no greenhouse blanket.  Note that a larger warming effect is possible if the “blanket” is allowed to stratify so that the bottom surface is hotter than the top.&lt;/p&gt;&#xA;&lt;p&gt;So, with no greenhouse gasses in the atmosphere: &lt;span class=&quot;math-container&quot;&gt;$$F_{sun}=\sigma T^4,$$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$F_{sun}$&lt;/span&gt; is the average, over the whole surface of the earth, of the heat flux absorbed from the sun (roughly &lt;span class=&quot;math-container&quot;&gt;$240 W/m^2$&lt;/span&gt;), &lt;span class=&quot;math-container&quot;&gt;$\sigma$&lt;/span&gt; is the Stefan-Boltzmann constant, &lt;span class=&quot;math-container&quot;&gt;$5.67 \times 10^{-8}Wm^{-2}K^{-4}$&lt;/span&gt;, and T is the average temperature of the earth's surface. This results in &lt;span class=&quot;math-container&quot;&gt;$T=255K=-18^{\circ}C$&lt;/span&gt;.  Pretty chilly.&lt;/p&gt;&#xA;&lt;p&gt;With a &amp;quot;perfect&amp;quot; greenhouse atmosphere, &lt;span class=&quot;math-container&quot;&gt;$$2F_{sun}=\sigma T^4,$$&lt;/span&gt; which results in &lt;span class=&quot;math-container&quot;&gt;$T=303K=30^{\circ}C$&lt;/span&gt;, about 15 degrees warmer than the present average.  You could reach a slightly higher average surface temperature--perhaps a couple of degrees--by assuming that the ice caps melt, lowering the albedo.&lt;/p&gt;&#xA;" OwnerUserId="12008" LastEditorUserId="12008" LastEditDate="2021-02-07T17:23:00.763" LastActivityDate="2021-02-07T17:23:00.763" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20765" PostTypeId="2" ParentId="8587" CreationDate="2021-02-06T20:46:49.130" Score="-2" Body="&lt;p&gt;&lt;a href=&quot;https://products.kitsapsun.com/archive/1998/11-19/0016_extinction__piece_of_dinosaur-kil.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://products.kitsapsun.com/archive/1998/11-19/0016_extinction__piece_of_dinosaur-kil.html&lt;/a&gt;&#xA;Here you go. Its amazing to see what happened to Earth, at the end of the Mesazoic.&lt;/p&gt;&#xA;" OwnerUserId="21772" LastActivityDate="2021-02-06T20:46:49.130" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20766" PostTypeId="2" ParentId="20483" CreationDate="2021-02-07T04:10:19.950" Score="3" Body="&lt;p&gt;It is not hard to do this calculation if you have global topography. Using a version with &lt;span class=&quot;math-container&quot;&gt;$\frac{1}{6}$&lt;/span&gt;- degree resolution and a sea level rise of 1027 m, the result is @Erik's value of 445 million cubic km. Here's the bit of MATLAB code:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;H = 1027;   % sea level rise (m)&#xA;topo(topo&amp;lt;0) = 0;   % change all ocean depths to zero&#xA;topo(topo&amp;gt;H) = H;   % level off all land at a height of H&#xA;topo = topo.*(cosd(lat')*ones(1,2160)); % land volume per grid cell&#xA;land = sum(topo(:))*18.5^2/1000; % total land volume in km^3&#xA;water = sum(cosd(lat))*2160*18.5^2*H/1000 - land; % added water volume&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Greenland and Antarctica fare ok, but Europe and Australia are basically gone:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/iuKle.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iuKle.png&quot; alt=&quot;world map with 1027m sea level rise&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12008" LastActivityDate="2021-02-07T04:10:19.950" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20768" PostTypeId="2" ParentId="20760" CreationDate="2021-02-07T14:02:59.537" Score="2" Body="&lt;p&gt;Yes, the deterministic GFS model (one model) has higher spatial resolution than the GEFS models (31 models). That is, that the latitude and longitude of the entire world is incremented by 0.25° in the GFS and 0.5° in the GEFS &lt;a href=&quot;https://nomads.ncep.noaa.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;(they upgraded both in the past two years)&lt;/a&gt;. When people say &amp;quot;high resolution,&amp;quot; think of it like &amp;quot;more pixels&amp;quot; on a video (like &lt;a href=&quot;https://en.wikipedia.org/wiki/1080p&quot; rel=&quot;nofollow noreferrer&quot;&gt;1080p&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;On a more technical note, &lt;a href=&quot;https://www.e-education.psu.edu/worldofweather/node/2112&quot; rel=&quot;nofollow noreferrer&quot;&gt;the GFS's (internal) resolution&lt;/a&gt; was once described as T-numbers, which counts the number of waves that can be fitted. The GFS could fit &lt;a href=&quot;https://vlab.ncep.noaa.gov/web/gfs/documentation&quot; rel=&quot;nofollow noreferrer&quot;&gt;1534 waves&lt;/a&gt;. However, since the upgrade in the dynamical core, the resolution has taken a different number. I don't exactly know the physical interpretation of the C-number, but the &lt;a href=&quot;https://www.emc.ncep.noaa.gov/emc/pages/numerical_forecast_systems/gefs.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;GEFS's C-number is currently C384&lt;/a&gt; (my guess is that it is the number of cubes on one face of the cubed sphere).&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-02-07T14:02:59.537" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20769" PostTypeId="2" ParentId="20763" CreationDate="2021-02-07T14:14:01.353" Score="1" Body="&lt;p&gt;The United States Geological survey might have some data on soil&#xA;As should the US Dept of Agriculture.&#xA;More to it, Universities with Agriculture departments&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-02-07T14:14:01.353" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20771" PostTypeId="2" ParentId="20757" CreationDate="2021-02-07T14:49:38.210" Score="-3" Body="&lt;p&gt;Without CO&lt;sub&gt;2&lt;/sub&gt;, Earth would be as cold as Mars or the outer planets between 200-250 Kelvin (-73 °C to -23 °C or -100 °F to -10 °F).&lt;/p&gt;&#xA;&lt;p&gt;As for more, a 20% gain in current CO&lt;sub&gt;2&lt;/sub&gt; would be 504 Parts per million in Atmosphere. That's impossible without a century time frame. But temperature predictions have failed to coalesce. Namely computer models that fail to predict actual temp increases.&lt;/p&gt;&#xA;&lt;p&gt;Google John Tyndall.&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/John_Tyndall&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/John_Tyndall&lt;/a&gt;&#xA;He measured the radiative properties of CO&lt;sub&gt;2&lt;/sub&gt; and other “greenhouse gases”  in the late 1850s&#xA;if you want a longer time-frame for human CO&lt;sub&gt;2&lt;/sub&gt; emissions this should do. Note temperature curve failed to obey CO&lt;sub&gt;2&lt;/sub&gt; curve. Also note, humanity built it's first civilizations where it's constantly warm....Mesopotamia, Egypt, Minoans....&lt;a href=&quot;https://i.stack.imgur.com/2MYko.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2MYko.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Overall CO&lt;sub&gt;2&lt;/sub&gt; input's have to be logarithmic. IN other words you want another degree of warming you need to double CO&lt;sub&gt;2&lt;/sub&gt; rates.&#xA;800 ppm&#xA;1600 ppm&#xA;3200 ppm&lt;/p&gt;&#xA;&lt;p&gt;You say 20%, that's 200,000 ppm, Impossible amount and a partially toxic atmosphere. CO&lt;sub&gt;2&lt;/sub&gt; begins to become toxic at around 10,000 ppm.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastEditorUserId="2470" LastEditDate="2021-10-10T04:40:11.430" LastActivityDate="2021-10-10T04:40:11.430" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20772" PostTypeId="2" ParentId="2755" CreationDate="2021-02-07T16:21:21.747" Score="1" Body="&lt;p&gt;Depiction of global carbon in gigatons (Billions of tons)&#xA;&lt;a href=&quot;https://i.stack.imgur.com/06q7n.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/06q7n.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.researchgate.net/figure/Depiction-of-the-global-carbon-budget-in-gigatons-billions-of-tons-of-carbon-Values-in_fig1_330383444&quot; rel=&quot;nofollow noreferrer&quot;&gt;Origin&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastEditorUserId="1079" LastEditDate="2021-02-09T10:58:20.943" LastActivityDate="2021-02-09T10:58:20.943" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20773" PostTypeId="2" ParentId="14903" CreationDate="2021-02-07T17:57:34.653" Score="1" Body="&lt;p&gt;The enzymes from maggots bred on plastic allowed ground up larva paste to also digest. I believe they were able to isolate and synthetically generate the enzymes.&#xA;Seemed like they can really just apply and let sit, but they probably narrowed down thermal and pressure conditions for maximum enzyme effectiveness.&lt;/p&gt;&#xA;" OwnerUserId="21781" LastActivityDate="2021-02-07T17:57:34.653" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20774" PostTypeId="1" CreationDate="2021-02-08T00:57:55.527" Score="19" ViewCount="8124" Body="&lt;p&gt;Several people have independently mentioned to me that all trees break at the same wind speed. This phenomenon is independent of type and size of the tree. Supposedly, Galileo already had described this phenomenon in one of &lt;a href=&quot;https://en.wikipedia.org/wiki/Two_New_Sciences&quot; rel=&quot;noreferrer&quot;&gt;his books&lt;/a&gt;. I think the wind speed was something like 150 km/h. I just do not understand what can cause such behavior to be valid for all size and types of trees.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2021-02-13T11:55:21.377" LastActivityDate="2021-02-13T11:55:21.377" Title="Why do trees break at the same wind speed?" Tags="|wind|forest|storms|hazardous|" AnswerCount="5" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="20775" PostTypeId="2" ParentId="20186" CreationDate="2021-02-08T01:17:14.310" Score="1" Body="&lt;p&gt;The key sentence here is&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;(not sure where the dataset is from)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Every cartographer has to decide what level of detail to use. Mathematicians discovered the &lt;a href=&quot;https://en.wikipedia.org/wiki/Coastline_paradox&quot; rel=&quot;nofollow noreferrer&quot;&gt;Coastline paradox&lt;/a&gt; for themselves &lt;a href=&quot;https://en.wikipedia.org/wiki/How_Long_Is_the_Coast_of_Britain%3F_Statistical_Self-Similarity_and_Fractional_Dimension&quot; rel=&quot;nofollow noreferrer&quot;&gt;in the 1960's&lt;/a&gt;, but it has always been a fundamental part of cartography.&lt;/p&gt;&#xA;&lt;p&gt;Different sources of data will come out of different methods of data collection, digitization, and storage.&lt;/p&gt;&#xA;&lt;p&gt;Regardless of the method used, somewhere there has to be a cutoff. You can't represent a detail smaller than the pen you (or computers) draw it with. The cutoff may be a concsious decision of the cartographer based on the purpose of the map, or an effect of the software used. Or just carelessness.&lt;/p&gt;&#xA;&lt;p&gt;But this means that different datasets and choices of representation will result in a radically different appearance of the map.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2021-03-11T15:05:34.833" LastActivityDate="2021-03-11T15:05:34.833" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20776" PostTypeId="2" ParentId="20774" CreationDate="2021-02-08T07:32:54.327" Score="37" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Why do trees break at the same wind speed?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/a31pA.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/a31pA.jpg&quot; alt=&quot;Damage caused by storm Klaus on the Landes forest&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;Image source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:St_Pierre_du_Mont_Klaus_3.JPG&quot; rel=&quot;noreferrer&quot;&gt;Wikimedia Commons&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Note that in the above image, that almost all of the trees had their tops snapped off. This claim is about tree's being snapped in two and is not about trees falling over or being uprooted.&lt;/p&gt;&#xA;&lt;p&gt;This claim is approximately valid for many species of trees. Apparently oaks can withstand slightly higher wind speeds than can pines. This claim does not apply to non-woody trees such as palms. It also is not true for species of woody trees that have evolved to live in areas where winds occasionally exceed 42 m/s (the equivalent of a category two hurricane).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;I just do not understand what can cause such behavior to be valid for all size and types of trees.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The authors of a recent paper on this subject attribute it to evolution. While winds frequently exceed 30 m/s (126 km/h), they very rarely exceed 50 m/s (180 km/h) in most places. The sweet spot in a tree's ability to sustain winds is between these limits. A tree that is too flimsy will be snapped by a heavy gale, won't live to maturity, and won't spawn offspring. A tree that is too sturdy is wasting precious energy building unneeded structure.&lt;/p&gt;&#xA;&lt;p&gt;As for why and how, it's a matter of allometry. Trees grow in girth as the age and add to their canopy. Tree allometry investigates the relationship between tree girth at chest height and other features of trees such as height and canopy area. The relationship between girth and canopy area is close to linear.&lt;/p&gt;&#xA;&lt;p&gt;Another factor is defects, which are places where a tree is most likely to snap in two. The extent of these defects also scales with size. Young trees lose tiny branches; the young tree eventually grows around these, leaving the small defect buried deep inside the tree as it ages. Older trees lose larger branches, leaving behind a potentially larger defect.&lt;/p&gt;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://journals.aps.org/pre/abstract/10.1103/PhysRevE.93.023001&quot; rel=&quot;noreferrer&quot;&gt;Critical wind speed at which trees break.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencemag.org/news/2016/02/trees-regardless-size-all-break-same-wind-speed-here-s-why&quot; rel=&quot;noreferrer&quot;&gt;Trees, regardless of size, all break at the same wind speed. Here’s why.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.fs.fed.us/psw/publications/documents/psw_gtr253/psw_gtr_253.pdf&quot; rel=&quot;noreferrer&quot;&gt;Urban Tree Database and Allometric Equations.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2021-02-09T08:21:42.563" LastActivityDate="2021-02-09T08:21:42.563" CommentCount="16" ContentLicense="CC BY-SA 4.0" />
  <row Id="20777" PostTypeId="2" ParentId="20774" CreationDate="2021-02-08T14:49:10.123" Score="9" Body="&lt;p&gt;As the other answer points out, this is very likely an evolutionary adaptation that balances sturdiness with unnecessary overengineering. From a physics perspective, the relatively constant breaking strength of a tree is related to &lt;em&gt;allometry&lt;/em&gt;, which is the relationship among the tree's proportions as it grows. A young tree is short and thin, with relatively little breaking strength, but it does not need to withstand very large wind shear due to its small size. As the tree's canopy grows larger, it must withstand greater forces from high winds, but is able to do so because of its thicker trunk/limbs. Because a tree's strength grows with the magnitude of forces it needs to withstand, it turns out that the windspeed required to break a tree is more or less constant across trees of different sizes/types. A tree that's twice as large might feel twice the wind shear, but it's also twice as strong.&lt;/p&gt;&#xA;" OwnerUserId="4971" LastActivityDate="2021-02-08T14:49:10.123" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="20778" PostTypeId="2" ParentId="20757" CreationDate="2021-02-08T17:28:40.053" Score="2" Body="&lt;p&gt;Looking at other planets in the solar system is a good way to get an indication of the role extreme variations of CO&lt;sub&gt;2&lt;/sub&gt; has. Mercury is closest to the sun, and has a high maximum temperature (449 centigrade) but a very low minimum (-170 centigrade). It has practically no atmosphere, and virtually no CO&lt;sub&gt;2&lt;/sub&gt;. Venus, on the other hand - the planet between the Earth and Mercury - has a minimum temperature that is higher than Mercury's maximum (!) at 465 centigrade.... and also the same temperature for the maximum. It has 96% CO&lt;sub&gt;2&lt;/sub&gt; in its thick atmosphere, keeping the planet very hot all of the time.&lt;/p&gt;&#xA;&lt;p&gt;Temperatures from: &lt;a href=&quot;http://earthguide.ucsd.edu/eoc/special_topics/teach/sp_climate_change/p_planet_temp.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://earthguide.ucsd.edu/eoc/special_topics/teach/sp_climate_change/p_planet_temp.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5381" LastEditorUserId="2470" LastEditDate="2021-02-16T01:43:31.783" LastActivityDate="2021-02-16T01:43:31.783" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20779" PostTypeId="2" ParentId="20774" CreationDate="2021-02-08T19:42:15.623" Score="3" Body="&lt;p&gt;One important additional factor is that the stress (and damage) isn't linear.  A very basic idea is that energy is velocity squared.  But &lt;a href=&quot;https://core.ac.uk/download/pdf/205734013.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Prahl et. al. 2008&lt;/a&gt; included some review of the theories on damage from winds and the two typical theories:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;wind loads, which are approximately proportional to the exerted pressure and, hence, to the square of the wind speed (e.g. Simiu and&#xA;Scanlan, 1996);&lt;/li&gt;&#xA;&lt;li&gt;the concept of proportionality between structural damage and the dissipation rate of the wind kinetic energy that scales with the third&#xA;power of wind speed (recently: Emanuel, 2005; Powell and Reinhold,&#xA;2007; Kantha, 2008).&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Then added that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In particular, the notion of a cubic relationship is backed by&#xA;empirical analysis of insurance records, which appear to exhibit cubic&#xA;or quartic behaviour depending on the storms under scrutiny (Munich&#xA;Re, 1993, 2001). However, recent literature provides evidence for a&#xA;much stronger increase of insured storm loss with wind gust speed&#xA;(Huang et al., 2001; Heneka and Ruck, 2008). For the insurance data&#xA;set that we employ here, Prahl et al. (2012) found a power law with&#xA;regionally varying exponents that approximately range between 8 and&#xA;12.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So whatever the exact relationship, there clearly are fundamental physical reasons that the impact ramps up so much more rapidly than the direct numbers themselves hint at, and so thinking of 150 kph (93 mph) vs 140 kph (85 mph) as the same as 100 kph (62 mph) vs 90 kph (56 mph) is a flaw we often face... and it makes more sense there'd be a relatively narrow tipping point, much like there is, for example, with a disease outbreak, as we've seen with COVID infection comparisons from different regions\countries.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2021-02-08T19:42:15.623" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="20780" PostTypeId="2" ParentId="20774" CreationDate="2021-02-08T21:13:08.947" Score="8" Body="&lt;p&gt;The general claim seems to be incorrect:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This phenomenon is independent of type and size of the tree.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Based on other answers, the claims around this appear to be that the scale of the tree doesn't matter.  For example the sciencemag.org article referenced in David Hammon's answer talks about experiments around different thicknesses of wood:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;As one might intuit, they found that for a fixed length, increasing the diameter made the rods stronger ... which explain the relationship of tree size parameters such as diameter and height&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So the size of the tree tends to not matter.  However, that article says nothing about the  composition of the wood which would require a different type of experiment altogether.  In addition the main claim is this:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Trees, regardless of their diameter, height, or elastic properties, don’t tend to break until wind speeds reach about 42 m/s (94 mph).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Note that this doesn't say there are no trees that can tolerate speeds above that without snapping, just that this is the lower bound.&lt;/p&gt;&#xA;&lt;p&gt;This &lt;a href=&quot;https://pamela-crawford.com/wind-tolerance-trees-palm-beach-landscape/&quot; rel=&quot;nofollow noreferrer&quot;&gt;landscaping website&lt;/a&gt; for a company based in Palm Beach Florida has an extensive list of tree species and their tolerance to high winds.  It has an long list of references but mentions this particular study frequently: &lt;a href=&quot;http://joa.isa-arbor.com/request.asp?JournalID=1&amp;amp;ArticleID=2708&amp;amp;Type=2&quot; rel=&quot;nofollow noreferrer&quot;&gt;WIND AND TREES: A SURVEY OF HOMEOWNERS&#xA;AFTER HURRICANE ANDREW&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;In this there are a number of confirmed cases of trees that survived wind speeds above 94MPH.  Some are documented to have survived wind speeds as high as 150MPH.  Note that while survival is different than having the trunk snapped, I think we can safely assume that if a tree survived, its trunk was not snapped.  Unless someone can produce evidence that this university study was somehow flawed, I think we can pretty well say that different species of trees have different snapping tolerances for wind.&lt;/p&gt;&#xA;&lt;p&gt;It may be true that in temperate regions where high wind speeds are very rare that all trees can tolerate roughly the same speed and that the size of the tree doesn't really matter.  But if you look to regions where hurricane-level winds are more common and the native plants that have adapted to those storms, this claim seems to fall apart in the face of evidence.&lt;/p&gt;&#xA;&lt;p&gt;Here are specific excerpts of the study mentioned above that explicitly contradict the claim that all species of trees have their trunks snapped by winds of 94MPH:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Trees along streets, in parks, in backyards were stripped of branches, uprooted or broken off by the &lt;strong&gt;145 mph sustained winds&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;[emphasis mine]&lt;/p&gt;&#xA;&lt;p&gt;I think we can all agree that a sustained wind speed of 145MPH is not approximately 94MPH.  It's not even remotely close.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Native Trees. Native tree species survived the hurricane better than exotics; chi-square analysis showed that 34% of exotic trees were still standing&#xA;after the hurricane while 66% of native trees were standing (n21/1 p&amp;lt;0.0001)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The paper also qualifies what standing/fallen means:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;How Did Trees Fall? When trees fell, they were either uprooted, broken at he trunk or both (Table 2).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;From which I conclude 'standing' means 'not broken at the trunk'.  This seems to be confirmed by following note about live oaks in particular:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Live oak was placed at the top of wind-resistance lists developed after hurricanes such as Camille (1969) and Frederick (1979) (1,6). Live oaks are well known to have exceedingly strong and resilient wood (1). In our study the few live oaks that failed we[r]e uprooted and &lt;strong&gt;not broken at the stem.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;[emphasis mine]&lt;/p&gt;&#xA;&lt;p&gt;It even calls into question the assertion that size is not a factor and notes this has been found in other studies:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Larger trees within a species were more likely to fall than samller trees. For example, the average height of fallen royal Palms was 15 m while the height of standing royal palms was 10 m. Fallen slash pines averaged 20 m high and 53 cm in diameter while standing pines were 17m and 45 cm. Few exceptions to this size failure relationship we[r]e live oak and pink trumpet. Other studies in forests have shown that three with larger diameters and heights were more likely&#xA;to be damaged by hurricane winds&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Lastly the paper gives an hypothesis for why some trees can tolerated higher wind speeds:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Native dicots were more tolerant of high winds than exotics. This is not surprising since South Florida native trees have long been subjected to hurricanes, providing a natural selection for wind resistance.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="18929" LastEditorUserId="18929" LastEditDate="2021-02-10T17:53:17.837" LastActivityDate="2021-02-10T17:53:17.837" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20782" PostTypeId="1" CreationDate="2021-02-09T14:07:49.463" Score="1" ViewCount="65" Body="&lt;p&gt;Any recommendations for a good online lecture series on Metamorphic Petrology?&lt;/p&gt;&#xA;&lt;p&gt;Thank you in advance.&lt;/p&gt;&#xA;" OwnerUserId="21799" LastActivityDate="2022-07-21T16:02:40.207" Title="Any recommendations for a good online lecture series on Metamorphic Petrology" Tags="|reference-request|metamorphism|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20783" PostTypeId="1" AcceptedAnswerId="20784" CreationDate="2021-02-09T16:38:05.927" Score="4" ViewCount="188" Body="&lt;p&gt;In one of Lorenz’s paper (I mean the meteorologists Edward Lorenz), he stated that the total potential energy of the whole atmosphere &lt;span class=&quot;math-container&quot;&gt;$P + I$&lt;/span&gt; (means the sum of potential energy and internal energy) is&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;P + I = c_p p_{00}^{-x} \int p^x \Theta dM&#xA;\end{equation}&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; is pressure, &lt;span class=&quot;math-container&quot;&gt;$p_{00}$&lt;/span&gt; is a standard pressure, and &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; is the ratio &lt;span class=&quot;math-container&quot;&gt;$(c_p - c_v)/c_p$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$c_v$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$c_p$&lt;/span&gt; are the specific heats of air,&lt;span class=&quot;math-container&quot;&gt;$\Theta$&lt;/span&gt; is the temperature and M is the mass.&lt;/p&gt;&#xA;&lt;p&gt;Based on my knowledge, the internal energy should be a simple form that&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;I = \int c_v T dM&#xA;\end{equation}&lt;/span&gt;&#xA;and the potential energy is actually the gravitational potential energy, which is&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;P = \int g h dM&#xA;\end{equation}&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; is the gravitational acceleration and &lt;span class=&quot;math-container&quot;&gt;$h$&lt;/span&gt; is the height. So my question is how did Lorenz derived his form of the total potential energy of the atmosphere? The original paper is &lt;em&gt;Energy and numerical weather prediction&lt;/em&gt;&lt;a href=&quot;https://www.tandfonline.com/doi/pdf/10.3402/tellusa.v12i4.9420&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lorenz 1960&lt;/a&gt;, and this equation was the first equation in the paper.&lt;/p&gt;&#xA;" OwnerUserId="21802" LastActivityDate="2021-02-09T17:57:00.620" Title="How to derive the total potential energy of the atmosphere?" Tags="|atmosphere|atmosphere-modelling|atmospheric-chemistry|atmospheric-radiation|atmospheric-circulation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20784" PostTypeId="2" ParentId="20783" CreationDate="2021-02-09T17:57:00.620" Score="3" Body="&lt;p&gt;First, let's acknowledge this fact: &lt;span class=&quot;math-container&quot;&gt;$$c_p=R+c_v \tag{1}$$&lt;/span&gt;,&#xA;where &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; is the specific gas constant.&lt;/p&gt;&#xA;&lt;p&gt;This means that &lt;span class=&quot;math-container&quot;&gt;$x=R/c_p$&lt;/span&gt;.&#xA;Rearranging the equation, we can see that &lt;span class=&quot;math-container&quot;&gt;$$P+I=\int{c_p\left(\frac{P}{P_{00}}\right)^{R/c_p}\Theta dM}\tag{2}$$&lt;/span&gt;&#xA;Notice that &lt;span class=&quot;math-container&quot;&gt;$\left(\frac{P}{P_{00}}\right)^{R/c_p}$&lt;/span&gt; is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Exner_function&quot; rel=&quot;nofollow noreferrer&quot;&gt;Exner function&lt;/a&gt;. By extension,&lt;span class=&quot;math-container&quot;&gt;$$P+I=\int{c_p T dM}\tag{3}$$&lt;/span&gt; If we rearrange (1) we can get&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$P+I=\int{c_v T+RT dM}\tag{4}$$&lt;/span&gt;.&#xA;You observed correctly that &lt;span class=&quot;math-container&quot;&gt;$I=\int{c_v T}dM$&lt;/span&gt;. This leaves &lt;span class=&quot;math-container&quot;&gt;$$P=\int{RT dM}\tag{5}$$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Using the ideal gas law,&lt;span class=&quot;math-container&quot;&gt;$$P=\int{P\alpha dM}$$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt; is specific volume. This makes (4) look like &lt;span class=&quot;math-container&quot;&gt;$$P+I=\int{c_v T+P\alpha dM}\tag{4}$$&lt;/span&gt; which is just a restatement of the first law of thermodynamics: &lt;span class=&quot;math-container&quot;&gt;$\delta q = c_v dT + p d\alpha$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-02-09T17:57:00.620" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="20785" PostTypeId="2" ParentId="20774" CreationDate="2021-02-09T19:41:04.083" Score="5" Body="&lt;p&gt;Some excellent answers are already available, but they are all examining a single tree in isolation, as if putting a tree to a wind tunnel to see whether it snaps or not.  That's not how every trees species handles winds.&lt;/p&gt;&#xA;&lt;p&gt;At the latitudes I'm used to, which is the temperate climate of Europe, the fastest winds blow over elevated terrain which is often continuously forested.  And the trees in the forest protect each other against the effects of the wind; massive clearings or other unnatural edges of the forest can act as vulnerabilities.&lt;/p&gt;&#xA;&lt;p&gt;The impact of the wind certainly depends not just on wind speed, but also on wind direction relative to terrain features and to various vulnerabilities including clearings, unsuitable tree varieties man-planted to higher elevations than where they evolved, or perhaps some calamitous diseases.  The exceptionally fast winds that can snap any trees aren't steady at all and I'm not aware of any meaningful research into the gust speeds which actually start the snapping within a forest; we just know the general wind speeds during the area in the hours during which a forest was destroyed.&lt;/p&gt;&#xA;&lt;p&gt;My point is: &lt;strong&gt;once many trees start snapping for any reason, other nearby trees, and also any downwind trees, start losing their usual physical protection from the wind&lt;/strong&gt;.  This means locally faster wind gusts, gradually extending to destruction of a large forest area.  Some exceptionally strong trees may survive, but if the tree species is well adapted to dense forests, it will rarely survive destruction of the said forest through a 100-years strong gale.&lt;/p&gt;&#xA;&lt;p&gt;There are differences between tree species.  Scrub pines can survive wind speeds that are unthinkable for any uprights.&lt;/p&gt;&#xA;&lt;p&gt;Some of you can perform an experiment.  Plant a line of apple trees and a line of spruces on a more or less exposed garden and count the snapped trees over the next 100 years.  Replace any trees that die from age or disease as you go.  (Spruces prefer the protection of a forest.  Apple trees prefer a lot of sunlight.  The suggested experiment is biased against spruces from the start; but spruces will also quickly outgrow the apple trees, gaining more exposition to the wind, biasing the experiment even further.)  Preliminary results that I have, although I haven't completed the first 100 years yet, nor reached any level of statistical significance, suggest that exposed spruces seem to snap more often than exposed apple trees.&lt;/p&gt;&#xA;&lt;p&gt;And the unnaturalness of this experiment brings me to this conclusion.  Trees develop in conditions where they are generally able to withstand the winds throughout their lifetime.  If that takes a forest, fine, they will thrive in forests.  If an occasional exceptional wind takes down the entire forest, the tree species can eventually repopulate the area, but only as long as their competitors have been taken down as well, so it pays off to stay within some proximity to the durability of those competitors.&lt;/p&gt;&#xA;" OwnerUserId="12117" LastActivityDate="2021-02-09T19:41:04.083" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20787" PostTypeId="2" ParentId="19733" CreationDate="2021-02-10T09:08:40.607" Score="2" Body="&lt;p&gt;I hope I can explain this well! I will focus my answer on the ITCZ in the Pacific Ocean. The first point is that the Coriolis force is zero at the equator and maximum at the poles &lt;a href=&quot;https://en.wikipedia.org/wiki/Coriolis_force&quot; rel=&quot;nofollow noreferrer&quot;&gt;(1)&lt;/a&gt;. So, another factor comes into play &lt;a href=&quot;https://en.wikipedia.org/wiki/Walker_circulation&quot; rel=&quot;nofollow noreferrer&quot;&gt;&amp;quot;the walker circulation&lt;/a&gt; which is strongly tied to &lt;a href=&quot;https://en.wikipedia.org/wiki/El_Ni%C3%B1o%E2%80%93Southern_Oscillation&quot; rel=&quot;nofollow noreferrer&quot;&gt;El Niño–Southern Oscillation (ENSO)&lt;/a&gt;. ENSO states are 3: normal conditions, La Niña, and El Niño.&lt;/p&gt;&#xA;&lt;p&gt;Given that Coriolis force is minimal around the equator, other wind drivers are more important. El Niño (La Niña) occurs when the tropical Sea surface Temperature (SST) in the central and eastern Pacific ocean is warmer (cooler) than the multi-decadal climate average. During normal conditions, higher pressure over the southeastern Pacific and lower pressure over the western Pacific drive easterly trade winds along the equator (known as Walker circulation), resulting in cold water upwelling and dry weather in the eastern Pacific. When the easterly trades are exceptionally strong, the eastern Pacific becomes colder and drier, resulting in La Niña conditions. The last case, El Niño occurs if the pressure over the eastern Pacific decreases: then easterly winds weaken or reverse direction, leading to a stronger ocean countercurrent that carries warm water into the eastern Pacific beside wetter weather conditions (&lt;a href=&quot;https://books.google.de/books/about/Meteorology_Today.html?id=8xWQPwAACAAJ&amp;amp;source=kp_book_description&amp;amp;redir_esc=y&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ahrens, 2009&lt;/a&gt;; &lt;a href=&quot;https://books.google.de/books?id=sjVfAAAACAAJ&amp;amp;dq=stull%20practical%20meteorology&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=2ahUKEwjC4f6g-t7uAhWM0eAKHfvUB-wQ6AEwAHoECAEQAg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stull, 2018&lt;/a&gt;). So during El Niño events, the winds are not always easterlies( heading west) in the western Pacific they are westerlies, and in the eastern Pacific are easterlies. And keep in mind that the ITCZ is &lt;a href=&quot;https://journals.ametsoc.org/view/journals/clim/24/1/2010jcli3716.1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;strongly linked to warm SST&lt;/a&gt;. That is why the ITCZ reaches the northernmost location in September (same as warm SST), although the Solar insolation peak in mid boreal summer (July).&lt;/p&gt;&#xA;&lt;p&gt;I hope this answers the question. late better than never ;-)&lt;/p&gt;&#xA;" OwnerUserId="20685" LastActivityDate="2021-02-10T09:08:40.607" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20788" PostTypeId="1" AcceptedAnswerId="20789" CreationDate="2021-02-10T18:11:10.063" Score="3" ViewCount="169" Body="&lt;p&gt;A tree while alive converts CO&lt;sub&gt;2&lt;/sub&gt; + water -&amp;gt; carbohydrates + O&lt;sub&gt;2&lt;/sub&gt;. However, once the tree dies, it decays, releasing CO&lt;sub&gt;2&lt;/sub&gt; back into the atmosphere. My question is, over an individual tree's overall existence, does a tree actually contribute to a reduction in atmospheric CO&lt;sub&gt;2&lt;/sub&gt;?&lt;/p&gt;&#xA;&lt;p&gt;I'm aware there's other pathways a tree could end up as a more long term carbon store (carbonaceous rocks), but mostly interested in if a tree were to die and fall in a forest, decay in 50-150 years, would it have contributed to a net reduction in CO&lt;sub&gt;2&lt;/sub&gt;, or does a tree typically act as more of a temporary 100+ year store of CO&lt;sub&gt;2&lt;/sub&gt;?&lt;/p&gt;&#xA;" OwnerUserId="14087" LastEditorUserId="2470" LastEditDate="2021-02-13T06:23:25.573" LastActivityDate="2021-02-13T06:23:25.573" Title="For a tree over its entire existence, does it actually have a net negative effect on atmospheric CO2?" Tags="|atmosphere|carbon-cycle|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20789" PostTypeId="2" ParentId="20788" CreationDate="2021-02-11T01:00:13.220" Score="3" Body="&lt;p&gt;A brief review of recent non-paywalled available literature indicates that such an effect likely exists but that it is difficult to quantify based on currently available data.&lt;/p&gt;&#xA;&lt;p&gt;Some amount of carbon from trees can be sequestered in the soil for periods time significantly longer than the typical above-ground decomposition time of organic matter, potentially for millennia. This clearly lengthens the carbon cycle time, but it is not clear to me whether this represents carbon &lt;em&gt;storage&lt;/em&gt;, as there does not seem to be a well established minimum cut-off time for this. The primary source for soil-sequestered carbon are tree roots, with leaf litter constituting a secondary source.&lt;/p&gt;&#xA;&lt;p&gt;The following paper (&lt;a href=&quot;https://hal.archives-ouvertes.fr/hal-01234833/file/13593_2014_Article_212.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;preprint online&lt;/a&gt;) addresses the question in the specific context of agroforestry, i.e. cropland interspersed with trees. The paper notes multiple times that the processes involved in soil sequestration are not well understood and that quantitative measurements and estimates vary widely, as one would expect based on differences in climatic and soil condition. Note on units: A Mg corresponds to a metric ton.&lt;/p&gt;&#xA;&lt;p&gt;Klaus Lorenz and Rattan Lala, &amp;quot;Soil organic carbon sequestration in agroforestry systems. A review.&amp;quot; &lt;em&gt;Agronomy for Sustainable Development&lt;/em&gt;, Vol. 34, No. 2, April 2014, pp. 443-454.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The soil organic carbon (SOC) pool, in particular, is the only terrestrial pool storing some carbon (C) for millennia which can be deliberately enhanced by agroforestry practices. [...] The SOC storage in agroforestry systems is also uncertain and may amount up to 300 Mg C ha&lt;sup&gt;−1&lt;/sup&gt; to 1 m depth.&#xA;[...] Further, between 30 and 300 Mg C ha&lt;sup&gt;−1&lt;/sup&gt; may be stored in agroforestry soils up to 1-m depth [...] The SOC sequestration depends primarily on the soil C input and soil stabilization processes. Plant root and rhizosphere inputs, in particular, make a large contribution to SOC [...] Litter fall and in turn SOC sequestration may be affected by stand-density management as, for example, higher stocking levels of trees enhance the vegetation C pool.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Another &lt;a href=&quot;https://www.fs.usda.gov/treesearch/pubs/download/15521.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt; that deals specifically with &lt;em&gt;urban&lt;/em&gt; trees mentions in passing that the soil accounts for a significant part of the carbon sequestered in &lt;em&gt;non-urban&lt;/em&gt; forests (presumably both naturally growing and human-managed):&lt;/p&gt;&#xA;&lt;p&gt;David J. Nowak and Daniel E. Crane, &amp;quot;Carbon storage and sequestration by urban trees in the USA&amp;quot;. &lt;em&gt;Environmental Pollution&lt;/em&gt; 116 (2002) 381–389&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Another area of the urban forest carbon cycle that this paper does not analyze is urban soils. Sixty-one percent of the total carbon in non-urban forest ecosystems&#xA;in the USA is stored in the soil environment (Birdsey and Heath, 1995). The amount of carbon from trees that is retained in urban soils, its residence time, and the amount of carbon currently stored in these soils remains to be investigated. It is likely, however, that urban soils contain less carbon per hectare than forest soils due to lower carbon inputs and increased soil decomposition rates due to warmer air and soil temperatures (e.g. Pouyat et al., 1997).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="5255" LastActivityDate="2021-02-11T01:00:13.220" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20790" PostTypeId="2" ParentId="20513" CreationDate="2021-02-11T18:22:35.450" Score="1" Body="&lt;p&gt;Based on calculations of the effect of melting ice on sea level, we know that to effect a 1 mm change in global sea level requires around 360 km3 water. The largest lake by volume, &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Baikal&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Baikal&lt;/a&gt;, contains just under 24,000 km3 of water. So if you created an equivalent lake you would lower sea level by 66 mm. At current rates of global sea level rise that would offset less than 20 years of melting ice and thermal expansion.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastEditorUserId="18990" LastEditDate="2021-02-12T03:09:13.210" LastActivityDate="2021-02-12T03:09:13.210" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20791" PostTypeId="1" CreationDate="2021-02-11T22:58:50.580" Score="1" ViewCount="54" Body="&lt;p&gt;This question is a result of recent news that Earth had a &amp;quot;boring billion&amp;quot; years in which mountains ceased to grow, and subsequently hindered life evolution.&lt;/p&gt;&#xA;&lt;p&gt;The article went on to give extraordinary details the scientists have provided.&#xA;They know that the Earth's mountains were not growing anymore, the crust was then thinning, and the ocean life couldn't get nutrients to help evolution.&lt;/p&gt;&#xA;&lt;p&gt;There was also a recent animation of Earth's tectonic plates over their lifetime and how the continents shaped into what they are now.&lt;/p&gt;&#xA;&lt;p&gt;How did they know all that stuff?  How did they know the tectonic plate moved from here to here a few billion years ago? Or how mountains no longer grow, or, or, or...&lt;/p&gt;&#xA;&lt;p&gt;I understand the concept of carbon-dating, and that's about it. Are there are any other crazy methods that enable them to make these mind-blowing measurements?&lt;/p&gt;&#xA;&lt;p&gt;I don't mind a detailed, jargon-filled explanation, but hopefully it can still make sense to someone generally interested in Science like myself.&lt;/p&gt;&#xA;" OwnerUserId="17326" LastActivityDate="2021-02-26T12:54:21.400" Title="How on &quot;Earth&quot; can you make all those measurements of Earth forming?" Tags="|plate-tectonics|measurements|evolution|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20792" PostTypeId="1" CreationDate="2021-02-12T01:17:34.417" Score="7" ViewCount="404" Body="&lt;p&gt;Inside the entire Earth as a whole, and throughout our Solar System and galaxy, etc., magnesium is at least 14 times (or more) as common as calcium, atom-per-atom.&lt;/p&gt;&#xA;&lt;p&gt;But, on Earth's crust and oceans, calcium is at least as abundant, atom-per-atom, as magnesium....&lt;/p&gt;&#xA;&lt;p&gt;Why is this?    Calcium IS denser/heavier....  They're both Group-2....&lt;/p&gt;&#xA;" OwnerUserId="20985" LastActivityDate="2021-02-15T21:13:44.627" Title="Why is calcium so much more abundant in/on Earth's crust (and oceans) than it is elsewhere? (relatively speaking...)" Tags="|oceanography|geochemistry|crust|continental-crust|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20793" PostTypeId="1" CreationDate="2021-02-12T09:21:59.713" Score="1" ViewCount="26" Body="&lt;p&gt;I am currently attempting to read the article &amp;quot;Footwall topographic development during continental extension&amp;quot;. The article and its abstract can be found &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2003JF000115&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;When reading the abstract, I have trouble comprehending some of the sentences. The highlighted phrases below are the ones I have the most trouble understanding:&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;We show that patterns of catchment area, footwall relief, and catchment outlet spacing vary predictably and are related to the &lt;strong&gt;growth of the range‐bounding normal fault array&lt;/strong&gt;. In this semiarid region, &lt;strong&gt;full parsing&lt;/strong&gt; of footwall drainage area and removal of antecedent topography do not occur &lt;strong&gt;until fault arrays grow beyond two crustal‐scale segments&lt;/strong&gt;.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Is &amp;quot;growth of the range‐bounding normal fault array&amp;quot; related to the amount of displacement, i.e. do they mean that these things depend on the amount of displacement?&lt;/p&gt;&#xA;&lt;p&gt;I do not really understand what &amp;quot;growth of a fault array&amp;quot; means. Are we talking about fault linkage, or displacement increase?&lt;/p&gt;&#xA;&lt;p&gt;By &amp;quot;full parsing&amp;quot;, do they mean breaching of the barrier made by the footwall, i.e. creation of drainage channels?&lt;/p&gt;&#xA;&lt;p&gt;I have no idea what they mean by &amp;quot;two crustal-scale segments&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="21767" LastActivityDate="2021-02-12T09:21:59.713" Title="Understanding certain phrases in the article &quot;Footwall topographic development during continental extension&quot;" Tags="|terminology|tectonics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20794" PostTypeId="1" CreationDate="2021-02-12T16:21:56.613" Score="3" ViewCount="222" Body="&lt;p&gt;In areas of very cold temperatures (-20°C and below), it is not uncommon for small streams to freeze completely (as in, from top to bottom) and larger rivers to develop thick ice covers. However, there is usually still water flowing beneath the ice cover of the larger rivers. This situation can easily persist for weeks or months.&lt;/p&gt;&#xA;&lt;p&gt;Which leads me to my question - where does the water in the big river come from? Big rivers are fed by smaller rivers, which are fed by large streams, which in turn are fed by small streams. At some point, we get to streams that are frozen solid, and consequently will no longer feed water into the system. Yet, as the big rivers keep flowing into the sea, water is still removed from the system. At this point, I would expect that, after a few days, all water is drained from the system, and the flow stops, but that doesn't seem to be what happens. Where does the water that keeps flowing into the sea come from?&lt;/p&gt;&#xA;&lt;p&gt;(This is obviously not a big logical issue in rivers flowing towards the poles, but rivers flowing towards the equator, or parallel to it, should have this problem.)&lt;/p&gt;&#xA;" OwnerUserId="21818" LastEditorUserId="21818" LastEditDate="2021-02-12T16:53:15.087" LastActivityDate="2021-02-12T16:53:15.087" Title="As small streams freeze solid, how can big rivers continue to carry water?" Tags="|water|rivers|ice|winter|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20795" PostTypeId="2" ParentId="9593" CreationDate="2021-02-12T17:35:38.657" Score="0" Body="&lt;p&gt;Convection also plays an important part in making the eruption column rise further than it would just from its initial upward velocity alone.&lt;/p&gt;&#xA;" OwnerUserId="21819" LastActivityDate="2021-02-12T17:35:38.657" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20798" PostTypeId="2" ParentId="20792" CreationDate="2021-02-12T22:07:10.883" Score="2" Body="&lt;p&gt;Two factors need to be considered here.  Magnesium ions are smaller, thus forming more compact formula units, and they are also often mixed with iron ions which make the formula unit weight heavier than you expect.  Magnesium-rich mafic rock, being also iron-bearing and with compact ions, literally packs on the pounds and tends to sink deeper into the crust and the mantle compared with rock (even mafic rock) containing more calcium.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;A false bargain&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Magnesium may form lighter atoms than calcium, but it also forms smaller atoms--especially when the metal forms cations as in the most common minerals where the metal is bonded to oxygen.  So the magnesium compounds have less formula weight but pack that mass into less volume.  If we compare densities of corresponding calcium and magnesium compounds we see that these effects almost cancel out.  Data for these examples are taken from Wikipedia:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\text{CaO}$&lt;/span&gt;:  &lt;a href=&quot;https://en.wikipedia.org/wiki/Calcium_oxide&quot; rel=&quot;nofollow noreferrer&quot;&gt;3.34 g/cm³&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\text{MgO}$&lt;/span&gt;:  &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnesium_oxide&quot; rel=&quot;nofollow noreferrer&quot;&gt;3.6 g/cm³&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\text{Ca}_2\text{SiO}_4$&lt;/span&gt;:  &lt;a href=&quot;https://en.wikipedia.org/wiki/Larnite&quot; rel=&quot;nofollow noreferrer&quot;&gt;3.28-3.33 g/cm³&lt;/a&gt; (larnite)&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\text{Mg}_2\text{SiO}_4$&lt;/span&gt;:  &lt;a href=&quot;https://en.wikipedia.org/wiki/Larnite&quot; rel=&quot;nofollow noreferrer&quot;&gt;3.21-3.33 g/cm³&lt;/a&gt; (forsterite)&lt;/p&gt;&#xA;&lt;p&gt;So there is only a little density difference overall -- in a world where mafic rocks do not contain iron.  Ah, but they do.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Going green, but packing heavy&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Why is jade usually green?  The most common jade mineral is &lt;strong&gt;nephrite&lt;/strong&gt;, which is mainly a slightly hydrated calcium-magnesium silicate -- with a little iron mixed in to get that green color, at least at low levels of iron.  The &lt;a href=&quot;https://en.wikipedia.org/wiki/Nephrite&quot; rel=&quot;nofollow noreferrer&quot;&gt;formula for this mineral&lt;/a&gt; is a mouthful:  &lt;span class=&quot;math-container&quot;&gt;$\text{Ca}_2\color{green}{\text{(Mg,Fe)}}_5\text{Si}_8\text{O}_{22}\text{(OH)}_2$&lt;/span&gt;.  As indicated by the text in that suitable green color, the iron is intermixed with the magnesium, not with the calcium.  The same holds true with the simpler, and also green-colored, &lt;a href=&quot;https://en.wikipedia.org/wiki/Olivine&quot; rel=&quot;nofollow noreferrer&quot;&gt;olivine&lt;/a&gt;, &lt;span class=&quot;math-container&quot;&gt;$\text{(Mg,Fe)}_2\text{SiO}_{4}$&lt;/span&gt;, except that olivine can contain more iron than is usually found in nephrite.&lt;/p&gt;&#xA;&lt;p&gt;Magnesium and calcium both lie in Group 2 and both form ions with +2 charges.  But that alone does not mean they are intermixed in mineral structures.  To fit nicely into the precise, tightly packed solid phase ions must not only have consistent charges at a lattice site, they must also have consistent sizes.  Calcium ions, with an ionic radius of 114 pm (ionic radius data from &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Ionic_radius&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;), are simply too big to fit where there should be magnesium ions with a radius of 86 pm.  Iron with +2 charge in its high-spin state (oxides of transition metals usually have high-spin ions) comes in at 92 pm, not perfect but a much more acceptable charge/size doppelganger for magnesium.  While nephrite in green jade has only a little iron, olivine can have a full range of iron/magnesium ratio from forsterite (&lt;span class=&quot;math-container&quot;&gt;$\text{Mg}_2\text{SiO}_4$&lt;/span&gt;) to the dark fayalite &lt;span class=&quot;math-container&quot;&gt;$\text{Fe}_2\text{SiO}_4$&lt;/span&gt;, with &lt;a href=&quot;https://en.wikipedia.org/wiki/Olivine&quot; rel=&quot;nofollow noreferrer&quot;&gt;a wide range of densities to match&lt;/a&gt; -- all the way from 3.2 to 4.5 g/cm³.  This range overwhelms the small difference we saw earlier between calcium and magnesium compounds without iron noted earlier.&lt;/p&gt;&#xA;&lt;p&gt;So the combination of a common, small ionic size for iron and magnesium with a relatively heavy atomic weight for iron makes magnesium-rich rocks sufficiently iron-rich and closely-packed to weigh them down.  Calcium adds extra bulk from its own ions and remains iron free in its lattice sites of mineral lattices, so calcium-bearing minerals are less dense and tend to float into the crust (and even continental crust).&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Earth's Cream of the Crop&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;This answer may be compared with the one &lt;a href=&quot;https://earthscience.stackexchange.com/a/20711/20607&quot;&gt;here&lt;/a&gt; regarding the Martian crust.  There, we find more magnesium relative to calcium.  While the calcium vs magnesium/iron differentiation described above occurs there, lack of a specific continental crust means the differentiation is less.  Accordingly, the composition of the Martian crust is closer to that of the magnesium- and iron-rich mantle than that of the terrestrial crust.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2021-02-15T21:13:44.627" LastActivityDate="2021-02-15T21:13:44.627" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20799" PostTypeId="1" CreationDate="2021-02-13T09:59:46.000" Score="11" ViewCount="1991" Body="&lt;p&gt;Take our world and look at its surface geography: we have continents and oceans, mountains ridges and canyons, and so on. To my knowledge, most of it has been shaped by tectonic activity (&lt;em&gt;feel free to correct me&lt;/em&gt;).&lt;/p&gt;&#xA;&lt;p&gt;I'm looking into other things that would &lt;strong&gt;reshape a world on a large scale&lt;/strong&gt;. It can be natural phenomena or artificial activities, it can occur over millions of years or in a matter of hours or days, and so on. Anything you can think of, which realistically would be able to change a worlds geography.&lt;/p&gt;&#xA;&lt;p&gt;To be clear, I'm not looking for &amp;quot;small&amp;quot; regional changes (Mount St. Helen comes to mind), I'm looking for something that would at least reshape a big chunk of a continent, if not more.&#xA;At the same time, I don't want it to be so extreme to completely destroy the world (eg. Earth's early days meteor shower, which pretty much melted its entire surface, or worse).&lt;/p&gt;&#xA;&lt;p&gt;Hope it makes sense...&lt;/p&gt;&#xA;&lt;p&gt;EDIT: I've read some interesting replies so far. I'd like to point out that the changes I'm referring to would be noticeable on a world map.&#xA;For example, the creation of new landmasses (eg. volcanic islands), their disappearance, or their movement. Seas and oceans, mountain ridges, stuff like that.&#xA;Is there something that could explain the sea level lowering permanently, leading to new lands emerging? Other than volcanoes (and tectonic activity), are there other ways for mountains to form? Is there something that would explain a huge (as in the sized of a large nation like the US or China) depression to appear? Stuff like that...&lt;/p&gt;&#xA;" OwnerUserId="21836" OwnerDisplayName="Mr_Bober" LastEditorUserId="21836" LastEditDate="2021-02-14T21:48:14.533" LastActivityDate="2021-02-21T00:52:29.487" Title="Other than tectonic activity, what can reshape a world's surface?" Tags="|geography|" AnswerCount="10" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20800" PostTypeId="2" ParentId="20799" CreationDate="2021-02-13T14:01:22.963" Score="17" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Glacier&quot; rel=&quot;nofollow noreferrer&quot;&gt;Glaciers&lt;/a&gt; come to mind.  Their movements over hundreds or thousands of years can&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;abrade rock and debris from their substrate to create landforms such as cirques [enclosed valleys from which the glacier scooped up earth], moraines [accumulations of this earth deposited elsewhere], or fjords [narrow inlets surrounded by steep cliffs].&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Gone fishing&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;If you ever fished in the Great Lakes and reeled 8n some perch or walleye, thank the glaciers from the last Ice Age.  The Lakes are basically large versions of cirques that became filled with water.  From &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Great_Lakes&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Great Lakes began to form at the end of the Last Glacial Period around 14,000 years ago, as retreating ice sheets exposed the basins they had carved into the land, which then filled with meltwater.[1]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The Great Lakes basin is limited in size because it tends to be walled off by the surrounding moraines from those same glaciers, but the waters in that region flow directly into the Atlantic Ocean without passing through Hudson Bay or the Gulf id Mexico as they otherwise might have done.  Thus we have an example of the glaciers affecting a natural process across a continent.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Cited reference&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;1.&#xA;Cordell, Linda S.; Lightfoot, Kent; McManamon, Francis; Milner, George (2008). &lt;em&gt;Archaeology in America: An Encyclopedia: An Encyclopedia&lt;/em&gt;. ABC-CLIO. p. 1. ISBN 978-0-313-02189-3.  &lt;a href=&quot;https://books.google.com/books?id=arfWRW5OFVgC&amp;amp;pg=RA1-PA25#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;Link&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2021-02-19T01:14:39.187" LastActivityDate="2021-02-19T01:14:39.187" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20801" PostTypeId="1" AcceptedAnswerId="20817" CreationDate="2021-02-13T14:03:59.263" Score="2" ViewCount="243" Body="&lt;p&gt;I'm currently doing some analysis using atmospheric sounding data available at &lt;a href=&quot;http://www.weather.uwyo.edu/upperair/sounding.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;University of Wyoming&lt;/a&gt; (I assume these are from the GTS network).&lt;br /&gt;&#xA;But, the vertical resolution of the sounding data available at University of Wyoming is very low for my use case. Except for the low vertical resolution, this data is perfect for my analysis.&lt;/p&gt;&#xA;&lt;p&gt;Is there an atmospheric sounding dateset that has higher vertical resolution that I could use?&lt;/p&gt;&#xA;" OwnerUserId="9633" LastActivityDate="2021-02-15T19:15:17.217" Title="High vertical resolution atmospheric sounding data" Tags="|meteorology|open-data|radiosounding|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20802" PostTypeId="2" ParentId="20799" CreationDate="2021-02-13T15:07:55.583" Score="19" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Erosion&quot; rel=&quot;noreferrer&quot;&gt;Erosion&lt;/a&gt; is a powerful but slow and time consuming process that can make dramatic changes. The best example of this is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Grand_Canyon&quot; rel=&quot;noreferrer&quot;&gt;Grand Canyon&lt;/a&gt;. Carved by a river over at least 17 million years, 5000 to 10,000 feet deep, 277 miles long and 18 miles wide.&lt;/p&gt;&#xA;&lt;p&gt;Erosion, whether it be due to wind, rain, water flow in rivers, glaciers is a major cause of geology, in the form of mineral grains, boulders and rocks to be mobilized and dispersed over a wide region.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Weathering&quot; rel=&quot;noreferrer&quot;&gt;Weathering&lt;/a&gt; is another force that reshapes the surface of the Earth. Australia is a perfect example of this. Weathering results in the physical breakdown of the of the surface geology due to weather, thermal stresses, frost, crystal formations and decomposition, oxidation, biological activity, alternating patterns of hydration and dehydration over a very prolonged period of time. The difference between erosion and weathering is erosion causes movement of material, weathering happens  in situ.&lt;/p&gt;&#xA;&lt;p&gt;Fire tolerant plants such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Eucalyptus&quot; rel=&quot;noreferrer&quot;&gt;eucalyptus&lt;/a&gt; and fire as a result of natural forms of ignition, such as  lightening  can change the botany of a large region, again see Australia. Eucalyptus has been described as a weedy tree that came to dominate a landscape when less fire tolerant plants became extinct.&lt;/p&gt;&#xA;&lt;p&gt;Persistent fire or drought over a prolonged period can lead to permanent loss of flora resulting in desertification. Similarly, excessive rain due to climate change can lead to landslides and excessive erosion.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-02-13T15:07:55.583" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="20803" PostTypeId="2" ParentId="20801" CreationDate="2021-02-13T17:20:59.647" Score="3" Body="&lt;p&gt;Looking for similar for another recent question, I stumbled across &lt;a href=&quot;https://www.sparc-climate.org/data-centre/data-access/fisaps/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sparc-climate.org/data-centre/data-access/fisaps/&lt;/a&gt; which lists quite a few options on HVRRD (high vertical resolution radiosonde data)&lt;/p&gt;&#xA;&lt;p&gt;Looks like a lot to sift through, but if your project can work for past data over the US, I found that from &lt;a href=&quot;ftp://ftp.ncdc.noaa.gov/pub/data/ua/rrs-data/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ftp://ftp.ncdc.noaa.gov/pub/data/ua/rrs-data/&lt;/a&gt; I was able to download the files and extract them using their software, resulting in data every second, typically about 5-10 meters apart... here's a clipped view with a rough idea of the type of data it has (also has v-wnd):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fSuqr.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fSuqr.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Perhaps that fits your needs?&lt;/p&gt;&#xA;&lt;p&gt;If not, and you can't find any useful data from the first link, maybe also try looking around &lt;a href=&quot;https://madis-data.ncep.noaa.gov/madisPublic1/data/point/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://madis-data.ncep.noaa.gov/madisPublic1/data/point/&lt;/a&gt; ... there's things like ACARS (commercial aircraft sounding data), MADIS data (satellite), radio profilers, etc.  Though less confident you'll find a resolution you want, never hurts to try.&lt;/p&gt;&#xA;&lt;p&gt;But hopeful you'll find what you need with the HVRRD stuff!&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2021-02-13T17:20:59.647" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20804" PostTypeId="1" AcceptedAnswerId="20806" CreationDate="2021-02-13T19:26:55.450" Score="1" ViewCount="28" Body="&lt;p&gt;Pardon my naive question. But I heard this argument quite sometimes.&lt;/p&gt;&#xA;&lt;p&gt;One can find at the Schlumberger careers page the particularly interesting FAQ:&lt;/p&gt;&#xA;&lt;p&gt;“We are often told that oil is running out. Why should I join an aging industry?”&lt;/p&gt;&#xA;&lt;p&gt;The answer is:&#xA;Far from joining a dying industry, technology is ensuring that hydrocarbon resources will be extended, that the amounts recovered will increase and the challenges the technology represents will remain as exciting as ever.&lt;/p&gt;&#xA;&lt;p&gt;My question is what exactly is meant by “hydrocarbon resources will be extended”? Is the oil refilling somehow?&lt;/p&gt;&#xA;" OwnerUserId="21826" LastActivityDate="2021-02-14T08:30:38.307" Title="Hydrocarbon resources extension. How?" Tags="|geology|mineralogy|fossil-fuel|oil-reserves|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20805" PostTypeId="2" ParentId="20799" CreationDate="2021-02-13T20:10:31.917" Score="18" Body="&lt;p&gt;Asteroid strikes.  Anything from a smallish crater to re-liquefying the surface of the planet.&lt;/p&gt;&#xA;" OwnerUserId="21827" LastActivityDate="2021-02-13T20:10:31.917" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20806" PostTypeId="2" ParentId="20804" CreationDate="2021-02-13T20:20:49.100" Score="1" Body="&lt;p&gt;The quantities of oil in a deposit are listed under two categories: resources and reserves.&lt;/p&gt;&#xA;&lt;p&gt;Resources are deposits that could be converted to reserves if economic factors, prices and costs, were favorable.&lt;/p&gt;&#xA;&lt;p&gt;Reserves are deposits that can be extracted for a profit.&lt;/p&gt;&#xA;&lt;p&gt;What makes a deposit profitable involves many things:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The size of the deposit&lt;/li&gt;&#xA;&lt;li&gt;The quality of the deposit - the type of hydrocarbons in the deposit,&#xA;is it lighter fractions of oil or heavier or a mixture of the two. It&#xA;also depends on the amount of undesirable contaminants in the oil&#xA;such as sulfur.&lt;/li&gt;&#xA;&lt;li&gt;The depth of the deposit&lt;/li&gt;&#xA;&lt;li&gt;Ease or difficulty in accessing the deposit&lt;/li&gt;&#xA;&lt;li&gt;The flow rate achievable from the deposit: the number of barrels of&#xA;oil per day that can be extracted.&lt;/li&gt;&#xA;&lt;li&gt;How much gas is associated with the deposit and the type of gas&lt;/li&gt;&#xA;&lt;li&gt;Ease of getting the oil to a refinery&lt;/li&gt;&#xA;&lt;li&gt;How much of the total oil in the ground can eventually be extracted.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The amount of oil that can be extracted is heavily reliant on the technology used to extract it. With the introduction and use of technologies not previously available more oil might be able to be extracted from the deposit, or oil from deposits not previous considered for extraction could be converted to reserve status and become available to be extracted. When this happens the hydrocarbon resources have become extended.&lt;/p&gt;&#xA;&lt;p&gt;Similarly, new technology might make oil in different types of deposits capable of being extracted. This is what happened with oil shale deposits when fracking was developing. Until then oil shale deposit were largely untouched.&lt;/p&gt;&#xA;&lt;p&gt;By being able to extract oil from such new sources also extends the hydrocarbon resource.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-02-14T08:30:38.307" LastActivityDate="2021-02-14T08:30:38.307" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20807" PostTypeId="2" ParentId="20799" CreationDate="2021-02-14T04:33:18.927" Score="5" Body="&lt;p&gt;Another answer that hasn't yet been stated is &lt;strong&gt;life&lt;/strong&gt;. Land plants totally changed weathering patterns. And of course humans have radically altered the world at a global scale, from direct impact (mining, river redirection), to weather patterns from deforestation, to acidification of ocean and sea level rise from climate change.&lt;/p&gt;&#xA;&lt;p&gt;Edit: Another thing is &lt;strong&gt;volcanic activity&lt;/strong&gt;. Some volcanos aren't associated with tectonics (for example, the hawaiian islands are thought to be caused by hotspots in the mantle). While volcanos can contribute to local changes via eruptions, large enough eruptions can drastically alter the global weather for years at a time, for example via spewing out huge amounts of ash that changes how much sunlight can reach the Earth's surface.&lt;/p&gt;&#xA;" OwnerUserId="9578" LastActivityDate="2021-02-14T04:33:18.927" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20808" PostTypeId="1" CreationDate="2021-02-14T10:16:05.300" Score="3" ViewCount="185" Body="&lt;p&gt;I read coal form in all geologic times but what is oldest know coal source?&lt;/p&gt;&#xA;" OwnerUserId="20598" LastActivityDate="2021-02-14T11:03:59.077" Title="What is oldest known coal source?" Tags="|paleontology|mining|coal|energy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20810" PostTypeId="2" ParentId="20808" CreationDate="2021-02-14T11:03:59.077" Score="3" Body="&lt;p&gt;The first coal deposits were laid during the &lt;a href=&quot;https://en.wikipedia.org/wiki/Carboniferous&quot; rel=&quot;nofollow noreferrer&quot;&gt;Carboniferous period&lt;/a&gt;, between 358.9 million years ago and 298.9 million years ago.&lt;/p&gt;&#xA;&lt;p&gt;Within this period, the early &lt;a href=&quot;http://www.gondwanaresearch.com/hp/paleo2.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mississippian&lt;/a&gt; period from 358.9 to 346.7 Mya, was when the first coal deposits were being laid. During this period, coal was being laid in what is now eastern North America, specifically the &lt;a href=&quot;http://www.uky.edu/KGS/fossils/fossil-region-Mississippian-period.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kentucky&lt;/a&gt; region.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-02-14T11:03:59.077" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20811" PostTypeId="2" ParentId="20799" CreationDate="2021-02-14T11:35:09.757" Score="2" Body="&lt;p&gt;In the history of our planet there were a handful of volcanic events which shaped parts of continents (specifically, covered them in lava) and are linked to mass extinction events. &lt;a href=&quot;https://www.nature.com/news/earth-s-lost-history-of-planet-altering-eruptions-revealed-1.21630&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nature  had an article&lt;/a&gt; in 2017.&lt;/p&gt;&#xA;" OwnerUserId="5396" LastActivityDate="2021-02-14T11:35:09.757" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20813" PostTypeId="2" ParentId="20799" CreationDate="2021-02-15T09:36:58.913" Score="2" Body="&lt;p&gt;Slightly smaller than perhaps what your looking for but does fall under &amp;quot;noticeable on a world map&amp;quot;, Nuclear explosions. Specifically there have been plans for &amp;quot;civilian usage&amp;quot; in making ports, canals, tunnels though mountains etc. &lt;a href=&quot;https://en.wikipedia.org/wiki/Project_Plowshare#Proposals&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Project_Plowshare#Proposals&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The plans covered pretty much anything where you need to make a big hole. A new Panama canal though Nicaragua would thus seem to fit the bill for &amp;quot;noticeable&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="21837" LastActivityDate="2021-02-15T09:36:58.913" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20814" PostTypeId="2" ParentId="20799" CreationDate="2021-02-15T14:32:56.040" Score="4" Body="&lt;p&gt;The Netherlands reclaimed land from the sea and built huge dikes to keep back the water.&lt;/p&gt;&#xA;&lt;p&gt;So human activity consisting of moving dirt also reshapes the world's surface.&lt;/p&gt;&#xA;&lt;p&gt;Here's a randomly googled youtube video explaining what that consists of:&#xA;&lt;a href=&quot;https://www.youtube.com/watch?v=i6DRRHXt-PA&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=i6DRRHXt-PA&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18134" LastActivityDate="2021-02-15T14:32:56.040" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20815" PostTypeId="2" ParentId="20799" CreationDate="2021-02-15T16:35:42.600" Score="3" Body="&lt;h3&gt;Temperature changes&lt;/h3&gt;&#xA;&lt;p&gt;Lots of possible reasons for that (variation in solar output, variation in the composition of the atmosphere, changes in orbit, rotation or angle of the planet...).&lt;/p&gt;&#xA;&lt;p&gt;If it goes up, oceans expand (due to melting of ice caps and glaciers and expansion of water), and continents shrink. Inner seas and lakes may on the other hand shrink due to lower precipitations.&lt;/p&gt;&#xA;&lt;p&gt;It it goes down, the opposite happens.&lt;/p&gt;&#xA;&lt;p&gt;Also affects weather patterns, which may change forests to deserts. Won't necessarily change the &lt;strong&gt;shape&lt;/strong&gt; of a continent, but will definitely change what it looks like.&lt;/p&gt;&#xA;&lt;h3&gt;Erosion and deposition&lt;/h3&gt;&#xA;&lt;p&gt;Takes matter from one place (erosion) and moves it somewhere else (sedimentary deposits). In extreme cases, this can affect paths of rivers which may switch their output from a sea to an ocean and make that sea shrink or disappear.&lt;/p&gt;&#xA;&lt;h3&gt;Asteroids&lt;/h3&gt;&#xA;&lt;p&gt;See the Moon, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Vredefort_crater&quot; rel=&quot;nofollow noreferrer&quot;&gt;300 km-wide Vredefort Crater&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_impact_craters_on_Earth#10_Ma_or_more&quot; rel=&quot;nofollow noreferrer&quot;&gt;many others&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;h3&gt;Non-tectonic volcanoes&lt;/h3&gt;&#xA;&lt;p&gt;Create islands or mountains, expand land surfaces. Make create tsunamis which may have impacts on land features.&lt;/p&gt;&#xA;&lt;h3&gt;Humans via:&lt;/h3&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Land_reclamation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Land reclamation&lt;/a&gt;. Total area reclaimed currently exceeds &lt;span class=&quot;math-container&quot;&gt;$20,000 km^2$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Global warming (see temperature changes).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Creation of dams (and thus lakes), rerouting of rivers, irrigation (which may divert output from inner seas/lakes and dry them up)...&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Deforestation. Affects erosion (see above), irrigation, weather patterns, albedo...&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="5197" LastActivityDate="2021-02-15T16:35:42.600" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20817" PostTypeId="2" ParentId="20801" CreationDate="2021-02-15T19:15:17.217" Score="1" Body="&lt;p&gt;I have contacted Dr. Larry Oolman, who is in-charge of the weather data provided at &lt;a href=&quot;http://www.weather.uwyo.edu/upperair/sounding.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.weather.uwyo.edu/upperair/sounding.html&lt;/a&gt;, regarding this issue and he has informed me that several countries have started using a new binary format which usually contains higher resolution data.&lt;br /&gt;&#xA;He further added that there is a new site for these new sounding data, at &lt;a href=&quot;http://www.weather.uwyo.edu/upperair/bufrraob.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.weather.uwyo.edu/upperair/bufrraob.shtml&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;A sample sounding data from the new site is given below:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/lCwOv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lCwOv.png&quot; alt=&quot;Sample sounding data&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Which shows a vertical resolution of around 5 meters. If we assume an ascent rate of 5m/s, this means that the data is retrieved every second. Note that not all of the countries still not provide high vertical resolution data.&lt;/p&gt;&#xA;&lt;p&gt;As for me, the new site does not give any data over Indian region. I have talked with an Indian Meteorological Department (IMD) staff and he has told me that they are still supplying the data in ASCII format, which must be why there's no data over India in the new site.&lt;/p&gt;&#xA;" OwnerUserId="9633" LastActivityDate="2021-02-15T19:15:17.217" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20818" PostTypeId="1" AcceptedAnswerId="20825" CreationDate="2021-02-15T21:55:02.843" Score="1" ViewCount="198" Body="&lt;p&gt;If I look at an Earth's map, the Arctic/North Pole always appears just like water. Evidently this is actually covered by ice, with an area depending on the time of the year. If this area is bigger than than the United States and there have been very few expeditions, how do we know there are not any (big) islands beneath the ice, like a hidden mini continent?&lt;/p&gt;&#xA;&lt;p&gt;My guess is that submarines may have been able to map all out but it is a very wide area and submarines haven't been around for that long.&lt;/p&gt;&#xA;" OwnerUserId="21842" LastEditorUserId="2470" LastEditDate="2021-02-16T10:37:53.027" LastActivityDate="2021-02-23T06:48:03.173" Title="How do we know the Arctic is just ice?" Tags="|oceanography|geography|mapping|sea-ice|continent|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20821" PostTypeId="1" AcceptedAnswerId="20828" CreationDate="2021-02-16T04:04:14.900" Score="7" ViewCount="227" Body="&lt;p&gt;The Phys.org article &lt;a href=&quot;https://phys.org/news/2021-02-co2-dip-dinosaurs-south-america.html&quot; rel=&quot;noreferrer&quot;&gt;CO2 dip may have helped dinosaurs walk from South America to Greenland&lt;/a&gt; quotes Dennis Kent, &amp;quot;adjunct research scientist at Columbia University's Lamont-Doherty Earth Observatory&amp;quot; in the following:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;On Earth, areas around the equator are hot and humid, while adjacent areas in low latitudes tend to be very dry. Kent and Clemmensen say that on a planet supercharged with CO2, the differences between those climatic belts may have been extreme—perhaps too extreme for the sauropodomorph dinosaurs to cross.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;&amp;quot;We know that with higher CO2, the dry gets drier and the wet gets wetter,&amp;quot;&lt;/strong&gt; said Kent. 230 million years ago, the high CO2 conditions could have made the arid belts too dry to support the movements of large herbivores that need to eat a lot of vegetation to survive. The tropics, too, may have been locked into rainy, monsoon-like conditions that may not have been ideal for sauropodomorphs. There is little evidence they ventured forth from the temperate, mid-latitude habitats they were adapted to in Argentina and Brazil.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The article references Dennis V. Kent el al., &amp;quot;Northward dispersal of dinosaurs from Gondwana to Greenland at the mid-Norian (215–212 Ma, Late Triassic) dip in atmospheric pCO2,&amp;quot; PNAS (2021). &lt;a href=&quot;https://www.pnas.org/cgi/doi/10.1073/pnas.2020778118&quot; rel=&quot;noreferrer&quot;&gt;https://www.pnas.org/cgi/doi/10.1073/pnas.2020778118&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;but currently the link to the article is not working; perhaps it's not actually been published yet.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Why is it that &amp;quot;With higher CO2, the dry gets drier and the wet gets wetter&amp;quot;? Does this adage come from modeling, from data, or from both? Is it a well-accepted rule of thumb?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2021-04-18T23:46:35.580" Title="Why is it that &quot;With higher CO2, the dry gets drier and the wet gets wetter&quot;?" Tags="|climate-change|climate|models|climate-models|paleoclimatology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20822" PostTypeId="2" ParentId="20799" CreationDate="2021-02-16T04:06:15.790" Score="1" Body="&lt;p&gt;Some I don't see mentioned here.&lt;/p&gt;&#xA;&lt;p&gt;Gravity, esp. the gravity the moon exerts on the ocean, creating tides.&lt;/p&gt;&#xA;&lt;p&gt;Radiation, esp. solar radiation.&lt;/p&gt;&#xA;&lt;p&gt;Earth axial tilt, which causes seasons and affects biomes.&lt;/p&gt;&#xA;" OwnerUserId="21845" LastActivityDate="2021-02-16T04:06:15.790" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20823" PostTypeId="2" ParentId="20799" CreationDate="2021-02-16T07:09:37.730" Score="4" Body="&lt;p&gt;How about corals?&#xA;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Barrier_Reef&quot; rel=&quot;nofollow noreferrer&quot;&gt;Great barrier Reef&lt;/a&gt; is already quite noticable from space.&lt;/p&gt;&#xA;" OwnerUserId="21847" LastActivityDate="2021-02-16T07:09:37.730" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20824" PostTypeId="1" CreationDate="2021-02-16T10:47:04.460" Score="1" ViewCount="30" Body="&lt;p&gt;I read &lt;a href=&quot;https://www.climate.gov/news-features/climate-qa/which-emits-more-carbon-dioxide-volcanoes-or-human-activities&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; that volcanoes release about &amp;quot;0.6 billion metric tons of carbon dioxide per year&amp;quot;. I wonder though, how scientists can estimate the emissions from large regions with geological features that release carbon dioxide and methane. For example, here in the Czech Republic, we have countless springs with carbonated water. Some have only a few bubbles while others shoot out like a freshly opened bottle of sparkling wine. Since the Czech republic has an area of 78 870km² it seems impossible that geologists could ever count and measure the output from all these springs, especially since the vast majority of them probably seep their carbon into underground caves, which then leak into the surface soil and eventually the atmosphere. It seems to me, that there is probably carbon seeping into the atmosphere from every m² of land in the country, and at wildly varying rates. What kind of methods to geologist use to get even a rough estimate? Do they try like covering the ground with 100m² tarps and try gathering the carbon that comes up? I'm just guessing here...&lt;/p&gt;&#xA;" OwnerUserId="21848" LastActivityDate="2021-02-16T13:17:51.237" Title="How do geologists measure green house gass emmissions from large regions" Tags="|geology|climate-change|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20825" PostTypeId="2" ParentId="20818" CreationDate="2021-02-16T10:59:35.247" Score="3" Body="&lt;p&gt;The sea floor has been mapped using sonar from ships &lt;a href=&quot;https://2001-2009.state.gov/r/pa/ei/pix/b/sat/93321.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;as shown here&lt;/a&gt;, and radar. But the fact was first discovered long before these technologies existed by sailors who got stuck in the ice. The entire ice sheet is floating and spinning at a relatively high rate of speed. When they got stuck, they could see, from the stars, that they were moving. I cannot find it now, but I remember reading on project gutenburg a terrifying historic first hand account of being stuck up there, and seeing that they were moving away from Europe and civilization and could not move their ship.&lt;/p&gt;&#xA;" OwnerUserId="21848" LastActivityDate="2021-02-16T10:59:35.247" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20826" PostTypeId="2" ParentId="20818" CreationDate="2021-02-16T11:15:33.053" Score="3" Body="&lt;p&gt;The Arctic has already been &lt;a href=&quot;https://en.wikipedia.org/wiki/Arctic_exploration&quot; rel=&quot;nofollow noreferrer&quot;&gt;explored&lt;/a&gt; extensively by people traversing over the ice, by air and by naval submarines.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;On August 3, 1958, the American submarine &lt;a href=&quot;https://en.wikipedia.org/wiki/USS_Nautilus_(SSN-571)&quot; rel=&quot;nofollow noreferrer&quot;&gt;USS Nautilus (SSN-571)&lt;/a&gt; reached the North Pole without surfacing. It then proceeded to travel under the entire Polar ice cap. On March 17, 1959, the USS Skate (SSN-578) surfaced on the North Pole and dispersed the ashes of explorer Sir Hubert Wilkins. These journeys were part of military explorations stimulated by the Cold War context.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The USS Nautilus was part of the the US Navy &lt;a href=&quot;https://en.wikipedia.org/wiki/Arctic_Submarine_Laboratory&quot; rel=&quot;nofollow noreferrer&quot;&gt;Arctic Submarine Laboratory&lt;/a&gt;, which undertook numerous submariner explorations of the Arctic.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The research culminated in the transpolar submerged voyage of USS Nautilus in 1958 and included scores of under-ice cruises to gain scientific knowledge essential to Arctic submarine operations.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The Soviet Union did a similar exercise to the USS Nautilus expedition &lt;a href=&quot;https://en.wikipedia.org/wiki/Northern_Fleet&quot; rel=&quot;nofollow noreferrer&quot;&gt;in 1962&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Following the 1958 voyage of USS Nautilus, the Leninskiy Komsomol (named for Vladimir Lenin's Komsomol) traveled under the Arctic ice and surfaced at the North Pole on 17 July 1962.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;US submarine activity is &lt;a href=&quot;https://www.arctictoday.com/u-s-navy-submarines-surface-near-the-north-pole-as-icex-2020-gets-underway/&quot; rel=&quot;nofollow noreferrer&quot;&gt;still on going&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Two U.S. Navy fast-attack submarines will surface near the North Pole over the course of the exercise (see video below of the first of these, the USS Toledo, surfacing on March 4, 2020). The submarines will also conduct several transits through the region.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.express.co.uk/news/world/1151654/arctic-sea-nuclear-submarine-north-pole-us-navy-russia-spt&quot; rel=&quot;nofollow noreferrer&quot;&gt;The US is not the only country to have submarines in the Arctic&lt;/a&gt;, it's also part of &lt;a href=&quot;https://principia-scientific.com/why-russia-is-sending-robotic-submarines-to-the-arctic/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Russia's backyard&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.techexplorist.com/detailed-submarine-map-arctic-ocean/34098/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Non-military organizations are also exploring the Arctic&lt;/a&gt;,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Since 1997, the International Bathymetric Chart of the Arctic Ocean (IBCAO) has been the authoritative source of bathymetry for the Arctic Ocean.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-02-16T11:20:46.643" LastActivityDate="2021-02-16T11:20:46.643" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20827" PostTypeId="2" ParentId="20824" CreationDate="2021-02-16T13:17:51.237" Score="1" Body="&lt;p&gt;Tracking atmospheric species over the entire planet really is comparatively easy via satellites, compared to plastering entire swathes of land with measurement stations.&lt;/p&gt;&#xA;&lt;p&gt;You make one infrared image from an imaging satellite at the right wavelength and you got the entire country covered. The right wavelength to choose has to be&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;originating from the molecule in emission at the right altitude and&lt;/li&gt;&#xA;&lt;li&gt;be optically thin. If you know your emission is optically thin, the flux in your image is directly proportional to the mass that is emitting this flux. If it's not optically thin, complications apply, but the idea is the same.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;An example of the observational fleet that NASA has in orbit can be found &lt;a href=&quot;https://eospso.nasa.gov/content/nasas-earth-observing-system-project-science-office&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; (scroll down the page). There it also becomes clear, that various instruments are needed to cover the entire range of interesting atmospheric species, which necessitates a number of observation platforms/satellites.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2021-02-16T13:17:51.237" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20828" PostTypeId="2" ParentId="20821" CreationDate="2021-02-16T14:46:21.307" Score="7" Body="&lt;p&gt;To my best knowledge, the paper by &lt;a href=&quot;https://journals.ametsoc.org/view/journals/clim/19/21/jcli3990.1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Held &amp;amp; Soden (2006)&lt;/a&gt; is the first paper that discussed the concept of the rich get richer. They used the climate change experiments generated for the Fourth Assessment of the intergovernmental panel on Climate Change or in other words, climate projections using climate models forced with different CO2 scenarios.&lt;/p&gt;&#xA;&lt;p&gt;One of their findings is that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Assuming that the lower-tropospheric relative humidity is unchanged&#xA;and that the flow is un-changed, the poleward vapor transport and the&#xA;pattern of evaporation minus precipitation (E - P) increases&#xA;proportionally to the lower-tropospheric vapor, and in this sense wet&#xA;regions get wetter and dry regions drier.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;To explain, assuming warming earth leads to more evaporation and an increase in the air capacity to carry water vapor, therefore, relative humidity can be assumed unchanged in the &lt;a href=&quot;https://scied.ucar.edu/learning-zone/atmosphere/troposphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;lower-tropospheric&lt;/a&gt;. Simoustanly, with warmer mid and higher latitudes the act of the atmosphere (through General Circulation) to redistribute the heat is reduced. Thus, more water vapor remains in the regions of evaporation leading to wet regions get wetter and dry regions drier.&lt;/p&gt;&#xA;&lt;p&gt;Yes, this result is widely accepted in the community.&lt;/p&gt;&#xA;" OwnerUserId="20685" LastEditorUserId="725" LastEditDate="2021-04-18T23:46:35.580" LastActivityDate="2021-04-18T23:46:35.580" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20829" PostTypeId="1" CreationDate="2021-02-16T15:10:02.427" Score="1" ViewCount="187" Body="&lt;p&gt;The temperature of a planetary body in space varies with the fourth-root of the power incident upon it, this is derived from the Stefan-Boltzmann Law.&lt;/p&gt;&#xA;&lt;p&gt;This is understandable when applied to a black body in space. However, when applied to certain pressure levels (like 1 bar) at planets with a thick atmosphere the outcome is the same&lt;/p&gt;&#xA;&lt;p&gt;Meaning that the temperature of Venus at 1atm (Tv) should be the fourth-root of 1.91 times the temperature on Earth at 1atm (Te). Venus receives 1.91 times the solar insolation of Earth.&lt;/p&gt;&#xA;&lt;p&gt;Venus Tv=∜1.91 x Te&lt;/p&gt;&#xA;&lt;p&gt;Tv = 1.176 x 288&lt;/p&gt;&#xA;&lt;p&gt;Tv = 339 Kelvin&lt;/p&gt;&#xA;&lt;p&gt;For Titan, the temperature of a planetary body in space varies with the fourth-root of the power incident upon it, meaning that the temperature of Titan at 1atm (Tt) should be the fourth-root of 0.01089 times the temperature on Earth at 1atm (Te). Titan receives 0.01089 times the solar insolation of Earth.&lt;/p&gt;&#xA;&lt;p&gt;Titan Tt=∜0.01089 x Te&lt;/p&gt;&#xA;&lt;p&gt;Tt = 0.323 x 288&lt;/p&gt;&#xA;&lt;p&gt;Tt = 93 Kelvin&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th&gt;Planet&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Measured Temp 1atm&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Relative Solar Insolation&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;4th Root&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Calculated Temp&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Earth&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;~288 Kelvin&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;1.00&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;1.000&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;288 Kelvin&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Venus&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;~340 Kelvin&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;1.91&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;1.176&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;339 Kelvin&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Titan&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;~90 Kelvin&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;0.01089&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;0.316&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;93 Kelvin&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;" OwnerUserId="21841" LastEditorUserId="21841" LastEditDate="2021-02-16T17:11:01.070" LastActivityDate="2021-02-17T02:44:02.297" Title="Why is the average 1 Bar temperature on planets with a thick atmosphere proportional to the distance of the sun?" Tags="|atmosphere|geophysics|climate|thermodynamics|astronomy|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="20830" PostTypeId="2" ParentId="9593" CreationDate="2021-02-16T15:29:13.337" Score="7" Body="&lt;p&gt;You and @jeffronicus are right in saying that it is the exsolving gas that drives the eruption of magma at the surface and gives it momentum. However, I'd like to point out that in order for the gas to exsolve from the magma, it first needs to reach a certain depth in the conduit. See for instance the solubility curve for water, the most common volcanic gas:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/h55pE.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/h55pE.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;H&lt;sub&gt;2&lt;/sub&gt;O solubility in basaltic and rhyolitic melts at typical magmatic temperatures based on experimental data. From &lt;a href=&quot;https://doi.org/10.1016/C2015-0-00175-7&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Encyclopedia of Volcanoes (2nd edition, 2015)&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;It shows that if you take a rhyolitic magma with a typical, initial content of 4 wt% H&lt;sub&gt;2&lt;/sub&gt;O at depth (i.e., in the chamber), you need to rise it to ~4 km (1 kbar) to reach the saturation curve, thus to begin water exsolution. Which means that &lt;strong&gt;gas exsolution usually happens in the conduit, while the magma has already started ascending&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;So, your question actually leads to another: Why does magma start ascending from the chamber in the first place? Magma can stay for decades in its chamber, at equilibrium with the surrounding country rock (we speak of &amp;quot;lithostatic&amp;quot; pressure rather than hydrostatic, but it's the same thing with a different density). So why does it decide to start ascending one day? It is indeed a matter of &lt;strong&gt;overpressure, although not from above but from below&lt;/strong&gt;. Crustal magma reservoirs are sometimes recharged by inputs of &amp;quot;fresh&amp;quot; magma from deeper, generating an overpressure in the chamber that triggers the eruption. Some examples of this:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://doi.org/10.1007/s004450050274&quot; rel=&quot;nofollow noreferrer&quot;&gt;Effusive eruption of viscous silicic magma triggered and driven by recharge: a case study of the Cerro Chascon-Runtu Jarita Dome Complex in Southwest Bolivia&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://doi.org/10.1130/0-8137-2375-2.175&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mafic magma injection triggers eruption at Ilopango Caldera, El Salvador, Central America&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://doi.org/10.1130/G37333.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Magma reservoir response to transient recharge events: The case of Santorini volcano (Greece)&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="2958" LastEditDate="2022-07-08T16:06:42.010" LastActivityDate="2022-07-08T16:06:42.010" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20833" PostTypeId="1" CreationDate="2021-02-16T20:59:39.907" Score="1" ViewCount="56" Body="&lt;p&gt;I’m designing a fictional world setting for a game, and I would like to know whether it has a relative coherence based on science. (Don’t mind if it is an almost improbable scenario).&lt;/p&gt;&#xA;&lt;p&gt;Would it be possible, from the earth’s creation or during its various geomorphological changes, for all the following hypotheses to be probable?&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Earth has multiple natural satellites which create new natural phenomena (ex. extreme tides and tidal currents)&lt;/li&gt;&#xA;&lt;li&gt;Earth temperature is higher enough to melt the ice so that humans can sail through the north and south pole, but also low enough for people to survive.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;My thoughts: I was thinking maybe multiple asteroids colliding and some of them (big enough) entered the earth’s orbit and became natural satellites, while others crashed into the earth’s surface to reshape the landscape etc.&#xA;Alternatively, if there could be a whole different planet similar to earth which had multiple moons since it's creation.&lt;/p&gt;&#xA;" OwnerUserId="21851" LastActivityDate="2021-02-17T17:08:24.297" Title="Would it be possible, from the earth’s creation or during its various geomorphological changes, for all the following hypotheses to be probable?" Tags="|geophysics|oceanography|earth-history|satellites|tides|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20835" PostTypeId="2" ParentId="20829" CreationDate="2021-02-16T23:36:09.897" Score="-1" Body="&lt;p&gt;I will throw out 2 hypothesises to answer the why of the question. Not saying it is true, just saying that it may be valid hypothesises. And both hypothesises don't discount the internal properties of greenhouse gasses.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Somehow positive and negative feedback forces level each other out in the 1 bar thick atmosphere sytems on all 3 planets&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;There is another overruling equilibrium mechanism, as proposed by Dr. Ronan Connolly &amp;amp; Dr. Michael Connolly, who studied all the weather balloon data.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://youtu.be/XfRBr7PEawY?t=2506&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://youtu.be/XfRBr7PEawY?t=2506&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21841" LastEditorUserId="21841" LastEditDate="2021-02-17T02:44:02.297" LastActivityDate="2021-02-17T02:44:02.297" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20836" PostTypeId="1" CreationDate="2021-02-17T02:19:10.903" Score="1" ViewCount="31" Body="&lt;p&gt;I used to live in an are with a large factory that processes timber then uses the splinters to create OSB and other wood composites. They also have a formaldehyde factory for producing their own adhesives. Since they came to the area, there are extremely weird smells that are hard to identify using only human sensors. Sometimes it smells like wood, sometimes like some weird steamy smell, sometimes like a sharp smell, sometimes like burned wood etc. I asked the local Environmental Agency and they say that their measurements show okay values for Formaldehyde, but they don't really have continuous measurements, so I find it hard to trust them. They also mentioned that Terpenes might be the reason why people smell different smells.&lt;/p&gt;&#xA;&lt;p&gt;Now... I know this is a very complicated subject, but I was wondering what kind of substances could there be around? I would like to buy some measuring devices, but I don't really know what kind of instrument to get. Formaldehyde would be one of the compounds to measure, VOC's (which is actually a very broad term, as far as I can understand), but what else? What kind of substances might be generated by such a factory?&lt;/p&gt;&#xA;" OwnerUserId="21858" LastActivityDate="2021-02-17T02:19:10.903" Title="What pollutants can be next to a wood processing plant with formaldehyde factory?" Tags="|air-pollution|pollution|air-quality|environmental-sensors|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20837" PostTypeId="1" CreationDate="2021-02-17T13:36:04.437" Score="3" ViewCount="46" Body="&lt;p&gt;The RT video &lt;a href=&quot;https://youtu.be/jc-FFhdNG9A?t=840&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Permafrost Mystery: scientists explore giant Yamal Sinkhole&lt;/a&gt; (with English subtitles) shows scientists exploring the formation. In one scene after about &lt;code&gt;14:00&lt;/code&gt; two scientists are deploying a device made of two perhaps 30 meter or more long wires(?) separated by about 1.2 meters, held apart by a rigid brace. One scientist holds some electronic equipment with a cable going down to one side of the brace.&lt;/p&gt;&#xA;&lt;p&gt;Two screenshots are shown below. I can't tell if these long green wires go down into the hole as well or if those are something different, but I think they do, eventually.&lt;/p&gt;&#xA;&lt;p&gt;Can anyone identify this instrument and what it measures, or at least provide some insightful educated speculation?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Potentially related &lt;a href=&quot;https://www.mdpi.com/2076-3263/11/1/21&quot; rel=&quot;nofollow noreferrer&quot;&gt;Detecting and Mapping Gas Emission Craters on the Yamal and Gydan Peninsulas, Western Siberia&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wjfWi.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wjfWi.jpg&quot; alt=&quot;screenshot from the RT video &amp;quot;The Permafrost Mystery: scientists explore giant Yamal Sinkhole&amp;quot;&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/djhlP.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/djhlP.jpg&quot; alt=&quot;screenshot from the RT video &amp;quot;The Permafrost Mystery: scientists explore giant Yamal Sinkhole&amp;quot;&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2021-02-17T13:48:10.893" LastActivityDate="2021-02-17T15:04:00.977" Title="What instrumentation and/or measurement is likely being shown in this video of giant Siberian craters/sinkholes?" Tags="|measurements|instrumentation|field-measurements|identify-this-object|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20838" PostTypeId="2" ParentId="20837" CreationDate="2021-02-17T15:04:00.977" Score="1" Body="&lt;p&gt;It looks like a geophysical method. But a wide variety of such methods have been applied to the Yamal crater by &lt;a href=&quot;http://izdatgeo.ru/pdf/earth_cryo/2015-4/84_eng.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Olenchenko et al. (2015)&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The complex of geophysical survey techniques included electrical resistivity tomography (ERT), near-field transient electromagnetic sounding (Transient Electro Magnetic (TEM) sounding), magnetic survey, and radioactivity survey.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I'd say it looks like the first one (ERT), but it's just an &amp;quot;educated speculation&amp;quot;! :)&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2021-02-17T15:04:00.977" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20839" PostTypeId="2" ParentId="20833" CreationDate="2021-02-17T17:08:24.297" Score="1" Body="&lt;p&gt;The second part of the question is easy to answer - given that the Arctic has been ice free in relatively recent geological history, e.g. in the Mesozoic, and it is expected to be ice free in summer within a few decades as a result of global warming, positing a habitable planet where polar oceans are navigable, at least in summer seems fairly safe.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2021-02-17T17:08:24.297" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20840" PostTypeId="1" CreationDate="2021-02-17T19:42:09.413" Score="1" ViewCount="444" Body="&lt;p&gt;I'm interested about this rock formation in Arabian desert. The rock looks like melting chocolate.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/61zP2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/61zP2.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BOMiB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BOMiB.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;Not sure where the exact Location, the source says it around Al-Ula, Saudi Arabia. Here the image source: &lt;a href=&quot;https://www.instagram.com/p/CKAGbRcoa1r&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.instagram.com/p/CKAGbRcoa1r&lt;/a&gt; / &lt;a href=&quot;https://www.instagram.com/p/CKAZR1yohtM&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.instagram.com/p/CKAZR1yohtM&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;What this formation called?&#xA;what is the cause and how was this rock formed?&lt;/p&gt;&#xA;&lt;p&gt;I made a little research on google, some says this was fomed by water and/or wind. I know, there was water and rarely snowfall in Arabian desert (obviously wind too). My presumptuous opinion, it doesn't look like was formed by fast flowing water like river or flood or wind. Sorry for that, i'm not geologist.&lt;/p&gt;&#xA;&lt;p&gt;If the rock was eroded by water, how was it? By flood, river Or by glacial snow?&lt;/p&gt;&#xA;&lt;p&gt;I need more scientific detail from the people in geology field. Can somebody please explain to me and provide me some scientific literature about this rock formation. Thank you..&lt;/p&gt;&#xA;&lt;p&gt;Regards.&lt;/p&gt;&#xA;" OwnerDisplayName="user21860" LastEditorDisplayName="user21860" LastEditDate="2021-02-17T20:47:13.367" LastActivityDate="2021-02-22T05:29:07.597" Title="Arabian Desert rock formation" Tags="|geology|rocks|desert|erosion|weathering|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20842" PostTypeId="2" ParentId="4358" CreationDate="2021-02-17T21:37:01.680" Score="0" Body="&lt;p&gt;A completely frozen river is equivalent to a glacier&lt;/p&gt;&#xA;&lt;p&gt;There are glaciers that move, and there are glaciers that are static over periods of time.&lt;/p&gt;&#xA;&lt;p&gt;So the answer is yes&lt;/p&gt;&#xA;&lt;p&gt;However. Could play a definition of words in time and space game with this question. When the river is completely frozen it is not a river anymore.&lt;/p&gt;&#xA;&lt;p&gt;In that case the answer is no&lt;/p&gt;&#xA;" OwnerUserId="21841" LastEditorUserId="21841" LastEditDate="2021-02-17T22:55:56.503" LastActivityDate="2021-02-17T22:55:56.503" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20843" PostTypeId="1" CreationDate="2021-02-17T23:04:38.783" Score="1" ViewCount="119" Body="&lt;p&gt;I am an enthusiast in this area and reading some scientific articles on precipitation forecasting and solar irradiation, I was wondering if these two variables have any direct correlation or relationship.&lt;/p&gt;&#xA;&lt;p&gt;I have no experience to start a discussion and would appreciate some insights.&lt;/p&gt;&#xA;&lt;p&gt;Something like: Is it possible to determine a specific location that gives us both precipitation and solar irradiation, for example, to have a household self-sufficient in drinking water via PV?&lt;/p&gt;&#xA;&lt;p&gt;Regards!&lt;/p&gt;&#xA;" OwnerUserId="21862" LastActivityDate="2021-02-20T19:48:24.080" Title="Relationship between rainwater and solar radiation" Tags="|meteorology|rainfall|atmospheric-radiation|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20844" PostTypeId="2" ParentId="20843" CreationDate="2021-02-17T23:31:38.877" Score="0" Body="&lt;p&gt;The Hadley cell is a giant machine made of air. At the business end at the equator the solar zenith tracks by every day at supersonic speed, and heats the surface layer of the atmosphere while it races by. Here there is no issue of planetary rotation induced Coriolis force to contend with, so the heated and moisture rich air increases in volume and falls in density. Eventually it explodes upward in a giant set of daily convection thunderstorms that reach to the stratosphere. Violent storms that jet liner pilots sensibly avoid.&lt;/p&gt;&#xA;&lt;p&gt;As the moist air rises in the convection cell, it cools by adiabatic conversion of KE to PE and the precipitation process kicks in (it rains a lot) so the rising air dries out. At the tropopause the air has a problem, it cannot easily go back down because on ascent as it dried out it gained Latent Heat (both of vapour condensation, and for good measure also that of ice crystal fusion). Furthermore, the water that gave it that Latent Heat is now back on the ground, so while the air cooled at the moist adiabat on ascent, it is forced to warm at the dry adiabat on descent. So, guess what? Descending dry air gets to be warmer than descending moist air when falling through the same distance.&lt;/p&gt;&#xA;&lt;p&gt;So how does the air get back to the ground? Well, the only way to go is sideways, so it sets off on a long journey across the upper atmosphere towards the pole. Except it never gets there. Thanks to the Earth’s rapid rate of daily rotation the dry air is forced to track eastwards and eventually, in the Horse Latitudes it cannot go any further pole-ward, and so it is forced to descend.&lt;/p&gt;&#xA;&lt;p&gt;On forced descent the dry air will maintain a clear atmosphere, and so sunlight will be able to reach the ground more easily. At the surface the descended air creates a zone of high pressure before it sets off back to the equator as the surface Trade Winds. On crossing over the ocean, the Trade Winds pick up moisture from the water by forced evaporation of moving air, and eventually the now moisture rich air arrives back at the equator. Here in the Doldrums, it is now ready for the next daily passage of the solar zenith. It is then set off on its journey once again and forever through the cycle strokes of the giant Hadley cell convection machine.&lt;/p&gt;&#xA;" OwnerUserId="21841" LastEditorUserId="21841" LastEditDate="2021-02-18T16:32:24.977" LastActivityDate="2021-02-18T16:32:24.977" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20850" PostTypeId="1" AcceptedAnswerId="20864" CreationDate="2021-02-19T02:29:02.013" Score="2" ViewCount="281" Body="&lt;p&gt;As the title says, I'd like to know what the O&lt;sub&gt;2&lt;/sub&gt; concentration was during the late Miocene period. I've tried to look this up but I'm having a hard time finding any conclusive data on it, or even any graphs of oxygen concentration on a scale smaller that 100 million years. From what I can tell it should be lower than today, although I can't tell by how much.&lt;/p&gt;&#xA;" OwnerUserId="21866" LastEditorUserId="2470" LastEditDate="2021-02-19T08:26:28.320" LastActivityDate="2021-02-22T04:37:55.483" Title="What was the oxygen concentration in the air during the late miocene period?" Tags="|climate|earth-history|oxygen|air|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20851" PostTypeId="2" ParentId="7056" CreationDate="2021-02-19T21:54:30.327" Score="5" Body="&lt;p&gt;Major problems with sunlight\energy\temperatures for the &amp;quot;southern Hemisphere&amp;quot;.  &lt;a href=&quot;https://wiki.tfes.org/Flat_Earth_-_Frequently_Asked_Questions&quot; rel=&quot;noreferrer&quot;&gt;The Flat Earth Society&lt;/a&gt; offers this suggested map of a flat Earth and a rough idea of how seasons would work:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/psMQem.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/psMQem.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/fwEANm.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fwEANm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But because of the larger radius of the SH Summer circle, the sun would have to move faster to complete a circle in 24 hours during December.  That would mean less sunlight per area in the southern hemisphere (or putting it another way, the same amount of solar energy is given onto a larger area in the southern hemisphere, meaning less energy per location).   And that means colder temperatures.&lt;/p&gt;&#xA;&lt;p&gt;For that matter, that larger circle should mean the sun moving through the sky more quickly there, and thus shorter days despite being nearer to the central path?&lt;/p&gt;&#xA;&lt;p&gt;The one option to keep seasonal temperatures balanced would be moving the sun closer to give more heat, but that would mean even shorter daytimes.  And either would cause more asymmetry in seasons, day length, etc at the Equator and between the summer and winter comparisons.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2021-02-19T21:54:30.327" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20853" PostTypeId="1" CreationDate="2021-02-20T15:48:48.543" Score="1" ViewCount="51" Body="&lt;p&gt;A Geology proffessor recently told me that around 200,000 years ago, when homo sapiens emerged, that &lt;em&gt;&amp;quot;...all of civilisation can now fit on the width of a single strand of human hair.&amp;quot;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;I am perplexed! What did he mean by this?&lt;/p&gt;&#xA;" OwnerUserId="21871" LastActivityDate="2021-02-20T15:48:48.543" Title="puzzling statement on earth history!" Tags="|geology|earth-history|evolution|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20854" PostTypeId="1" CreationDate="2021-02-20T14:03:50.513" Score="4" ViewCount="132" Body="&lt;p&gt;A lot of misinformation about earth and it being a sink is spread everywhere, including what I was taught in school, I hope you well-informed folk can help me out.&lt;/p&gt;&#xA;&lt;p&gt;A &lt;em&gt;sort of&lt;/em&gt; side-note, if anyone has a book recommendation explaining these kinds of concepts and everything related to them, please do let me know. It seems as if most books on electrodynamics don't really examine these assumptions we usually make. Examples: why earth is a 'sink' for electrons?; how, when grounding houses -- does a ground connection act as a wire which connects back to the same circuit, even when it's a &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/7/7d/HomeEarthRodAustralia1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;single wire&lt;/a&gt; (taken from &lt;a href=&quot;https://en.wikipedia.org/wiki/Ground_(electricity)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ground&lt;/a&gt; wikipedia page) connected to ground?&#xA;And the list goes on.&lt;/p&gt;&#xA;&lt;p&gt;To quote my last question, I found it here: &lt;a href=&quot;https://electronics.stackexchange.com/a/148684&quot;&gt;https://electronics.stackexchange.com/a/148684&lt;/a&gt;&lt;br /&gt;&#xA;Quote:&#xA;&amp;quot;Current never ever ever ever flows &lt;em&gt;to&lt;/em&gt; earth. It only ever flows &lt;em&gt;through&lt;/em&gt; earth. Earth is just another wire - albeit a planet sized one. Electrons have to flow from one side of the power source back to the other. They can never flow out and never return.&amp;quot; – Majenko&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Moving on, the original question&lt;/strong&gt;:&#xA;Why aren't objects close to the surface polarized?&lt;br /&gt;&#xA;We know that by static inductance, when you rub two of the right materials together, one becomes negatively charged, and the other positively charged. Let's take one and get a neutrally charged material next to it, bringing it closer, we can see that it becomes polarized.&lt;/p&gt;&#xA;&lt;p&gt;I've read that earth's surface is negatively charged, -500,000 coulombs, to be sure. So bringing a neutrally charged object close to it would make it polarized, is what I think is logical.&lt;/p&gt;&#xA;&lt;p&gt;So why is my conclusion wrong, if it is wrong (doesn't seem right)? And why is it that earth is charged negatively?&lt;/p&gt;&#xA;" OwnerUserId="21884" OwnerDisplayName="Nizar K" LastEditorUserId="2958" LastEditDate="2021-02-28T18:14:02.003" LastActivityDate="2021-02-28T18:14:02.003" Title="If the earth's surface is negatively charged, why aren't objects close to the surface polarized?" Tags="|electromagnetism|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20855" PostTypeId="2" ParentId="20854" CreationDate="2021-02-20T14:40:21.747" Score="0" Body="&lt;p&gt;Yes, &lt;a href=&quot;https://hypertextbook.com/facts/1998/TreshaEdwards.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;the earth has a field strength.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;That page quotes field strength numbers of 300V/m or 150 newtons per coulomb. I've not bothered to do the equation for -0.5MC charge across the surface of the earth, but I expect it would line up with that.&lt;/p&gt;&#xA;&lt;p&gt;The next question is why we don't notice this. I believe it's dominated by other effects; regular tribocharging can build up multiple-kilovolt charges on an ordinary human, and they don't notice until they touch a grounded object and get a small zap.&lt;/p&gt;&#xA;" OwnerUserId="22277" OwnerDisplayName="pjc50" LastActivityDate="2021-02-20T14:40:21.747" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20856" PostTypeId="1" CreationDate="2021-02-20T19:07:24.260" Score="2" ViewCount="225" Body="&lt;p&gt;Is there a good chart of the geothermal gradient but near the surface? I haven't been able to find one because they are primarily studied at larger depths, but I would like to know the equilibria at different depths within 1 kilometer.&lt;/p&gt;&#xA;" OwnerUserId="21873" LastActivityDate="2021-02-21T09:28:48.117" Title="Geothermal gradient near surface?" Tags="|geothermal-heat|reference-request|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20857" PostTypeId="2" ParentId="20843" CreationDate="2021-02-20T19:48:24.080" Score="2" Body="&lt;p&gt;Any relationship or correlation? That is quite a broad standard. Invoking &lt;a href=&quot;https://en.wikipedia.org/wiki/Tobler%27s_first_law_of_geography#:%7E:text=The%20First%20Law%20of%20Geography,specifically%20for%20the%20inverse%20distance&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tobler's first law of geography&lt;/a&gt;, there is a relationship. I would question if there is such a thing universally, but there are some instances that we can see an overlap. For example, many deserts receive plenty of sunlight, but observe little rain.&lt;/p&gt;&#xA;&lt;p&gt;One of the first things that comes to mind are instances where these overlap. A plant needs both water and radiation to grow.&lt;/p&gt;&#xA;&lt;p&gt;Another thing that comes to mind is the investigation of &lt;a href=&quot;http://www.coupling-metrics.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;land-atmosphere coupling metrics&lt;/a&gt;. &lt;a href=&quot;http://cola.gmu.edu/dirmeyer/Coupling_metrics.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;There are plenty of metrics that try a variety of methods capturing a plethora of different dynamics.&lt;/a&gt; These are indirectly associated with sunshine, as the surface fluxes are driven by solar radiation.&lt;/p&gt;&#xA;&lt;p&gt;As far as finding a specific spot for self-sufficient drinking water, I am afraid that any relationship you get will not be one that will yield such a desired result. &lt;a href=&quot;https://insurify.com/blog/home-insurance/well-vs-city-water/&quot; rel=&quot;nofollow noreferrer&quot;&gt;If you want an environmentally friendly, generally reliable way of attaining water, try well water.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-02-20T19:48:24.080" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20860" PostTypeId="2" ParentId="20856" CreationDate="2021-02-21T09:28:48.117" Score="3" Body="&lt;p&gt;The trouble with geothermal gradients is they are not the same everywhere. It is generally accepted that the geothermal gradient is 25-30 °C/km but there can be local variations. In &lt;a href=&quot;https://energymining.sa.gov.au/geothermal/exploration_and_development/What_is_Geothermal_Energy&quot; rel=&quot;nofollow noreferrer&quot;&gt;South Australia&lt;/a&gt; the gradient is generally 30° C/km, but in the deeper parts of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cooper_Basin&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cooper Basin&lt;/a&gt; the gradient is 55-60 °C/km. &lt;a href=&quot;https://www.ablison.com/what-is-the-geothermal-gradient/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Elsewhere&lt;/a&gt;, at a depth of 200 ft the temp is 11 C. &lt;a href=&quot;http://www.geoelec.eu/wp-content/uploads/2011/09/UK-deep-geothermal-resources_JBusby.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;In the UK&lt;/a&gt; the average geothermal gradient is 26 °C/km, but locally it can be in excess of 35°C/km.&lt;/p&gt;&#xA;&lt;p&gt;With near surface depths, the &lt;a href=&quot;https://pubs.usgs.gov/bul/1172/report.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;ground temperature will vary with depth according to the time of day&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NIbWM.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NIbWM.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So to get an accurate geothermal map for your region would require localized data.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-02-21T09:28:48.117" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20862" PostTypeId="2" ParentId="4872" CreationDate="2021-02-21T16:59:31.470" Score="0" Body="&lt;p&gt;Satellite measurements have been done and the sea floor is sinking relative to the continental crust so sea level SHOULD be falling. In some places the continental rise is quite extreme, the places were loss of ice has changed the isostatic balance of the continent.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://Satellite%20measurements%20have%20been%20done%20and%20the%20sea%20floor%20is%20sinking%20relative%20to%20the%20continental%20crust%20so%20sea%20level%20SHOULD%20be%20falling.%20there%20are%20places%20where%20continental%20crust%20is%20rising,%20the%20places%20were%20there%20is%20suddenly%20far%20less%20weight%20from%20ice%20sheets.%20sciencedirect.com/science/article/abs/pii/S027737910200080X&quot; rel=&quot;nofollow noreferrer&quot;&gt;sciencedirect.com/science/article/abs/pii/S027737910200080X&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://climate.nasa.gov/blog/3002/sea-level-101-part-two-all-sea-level-is-local/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://climate.nasa.gov/blog/3002/sea-level-101-part-two-all-sea-level-is-local/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2021-02-21T16:59:31.470" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20863" PostTypeId="2" ParentId="20854" CreationDate="2021-02-21T19:39:40.377" Score="2" Body="&lt;p&gt;Think of the electric current as a fluid, and a battery or some other source of current as a pump. Change the earth for the ocean.&lt;/p&gt;&#xA;&lt;p&gt;I don't know about the negatively charged earth's surface, but those -500,000 coulombs are an absolute measure of charge. That charge is distributed over some surface, and the earth's surface is pretty big.&lt;/p&gt;&#xA;" OwnerUserId="21881" LastActivityDate="2021-02-21T19:39:40.377" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20864" PostTypeId="2" ParentId="20850" CreationDate="2021-02-22T04:37:55.483" Score="1" Body="&lt;p&gt;&lt;a href=&quot;https://www.researchgate.net/publication/256655103_Stable_carbon_isotopes_of_C3_plant_resins_and_ambers_record_changes_in_atmospheric_oxygen_since_the_Triassic&quot; rel=&quot;nofollow noreferrer&quot;&gt;R. Tappert et al (2013)&lt;/a&gt; used carbon isotopes in ambers as proxies for atmospheric oxygen concentrations. Their work indicates an initial Miocene O2 concentration of 16% and rising to about 20% at the end:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/XDbWu.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XDbWu.jpg&quot; alt=&quot;Comparison of predicted atmospheric pO2 from this study with previously proposed models that are based on mass balance calculations...&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It's pretty remarkable how different their results look from other models. Some think that some inferred upward trend in O2 levels since the Eocene gave rise to the mammals, or at least bigger brains in mammals.&lt;/p&gt;&#xA;&lt;p&gt;Hope this helps!&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2021-02-22T04:37:55.483" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20865" PostTypeId="2" ParentId="19044" CreationDate="2021-02-22T05:10:27.963" Score="1" Body="&lt;p&gt;You are referring to shale &amp;quot;boudins&amp;quot;: sausage-like structures that form when rock layers are compacted, break apart, and are pinched at the ends by differential compaction stresses:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/pg5fg.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pg5fg.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Their formation has nothing in common with how salt is deformed by stress. Salt is deformed by stress induced erosion and re-mineralization at grain boundary edges. It has more in common with the formation of marble and quartzite (though at far lower PT conditions).&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2021-02-22T05:10:27.963" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20866" PostTypeId="2" ParentId="20840" CreationDate="2021-02-22T05:29:07.597" Score="1" Body="&lt;p&gt;There are two water-related erosional process at work here:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The exhumation of main sandstone blocks caused by heavy rainfall, incising channels and carrying away the loose debris for deposition elsewhere as &amp;quot;sand&amp;quot;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Formation of weather resistant surfaces caused by dissolution and re-precipation of iron-rich minerals.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;You often see this process at work in any desert environment bearing iron-rich sandstones. The morphology, however, will differ based on the internal structure of the rock. Where high winds can carry sand, these iron-rich surfaces can become highly polished into a varnish-like surface.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2021-02-22T05:29:07.597" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20867" PostTypeId="2" ParentId="20818" CreationDate="2021-02-22T08:32:42.840" Score="2" Body="&lt;p&gt;You can study the &lt;a href=&quot;https://www.google.com/search?q=mapping%20arctic%20undersea%20relief&amp;amp;client=tablet-android-samsung&amp;amp;prmd=isnv&amp;amp;sxsrf=ALeKk01qqP6N8XjZ7iH40tEZHYMaZRSZkg:1613981579098&amp;amp;source=lnms&amp;amp;tbm=isch&amp;amp;sa=X&amp;amp;ved=2ahUKEwi5wcj1hf3uAhVUA2MBHXCBBhMQ_AUoAXoECAUQAQ&amp;amp;cshid=1613982829274&amp;amp;biw=768&amp;amp;bih=1024#imgrc=RvPh-ZnMBoY5QM&quot; rel=&quot;nofollow noreferrer&quot;&gt;many maps,&lt;/a&gt; it seems there is a giant ridge foming but the ice grinds it faster than it rises. Icebergs are grinding the arctic deeper than sea level, like 300/400 meters deep, also considering the glacial maxima when the sea level is lower and there is more ice, whatever mountains are rising in the arctic are weathered far below the sea level. The ice drifts dozens of meters every year.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/SRWIT.jpg&quot; alt=&quot;enter image description here&quot; /&gt;]&lt;a href=&quot;https://i.stack.imgur.com/SRWIT.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;5&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Many satellites fly over the arctic that can measure it's &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2017JC013697&quot; rel=&quot;nofollow noreferrer&quot;&gt;drift&lt;/a&gt; speed and ice depth.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Ugvmh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ugvmh.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here are some of the journeys of sonar craft measuring the seafloor&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mdxz2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mdxz2.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/s41597-020-0520-9/figures/3&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/s41597-020-0520-9/figures/3&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.com/search?q=arctic%20sonar&amp;amp;client=tablet-android-samsung&amp;amp;prmd=isvn&amp;amp;sxsrf=ALeKk03iSoViEbmdgk44GnLT3DIISqjKpg:1613982352492&amp;amp;source=lnms&amp;amp;tbm=isch&amp;amp;sa=X&amp;amp;ved=2ahUKEwi50KzmiP3uAhVcAmMBHW_sA5EQ_AUoAXoECAUQAQ&amp;amp;biw=768&amp;amp;bih=1024&amp;amp;dpr=2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Images of sonar equipment&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2021-02-23T06:48:03.173" LastActivityDate="2021-02-23T06:48:03.173" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20868" PostTypeId="2" ParentId="565" CreationDate="2021-02-22T13:18:43.203" Score="1" Body="&lt;p&gt;Whether it's an organism, it's alive, etc. are just labels commonly used when this issue is discussed among biologists or Earth scientists. However, a broader perspective leads to the notion of an emergent system.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&amp;quot;Emergence occurs when an entity is observed to have properties its parts do not have on their own, properties or behaviors which emerge only when the parts interact in a wider whole&amp;quot;&lt;/em&gt; (&lt;a href=&quot;https://en.wikipedia.org/wiki/Emergence&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Emergence&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;The properties that we often associate with life are not specific to life, but to complex systems with emergent properties. Therefore, exhibiting specific properties commonly associated with life doesn't imply the Earth is alive (although it does not deny it). Whether it fits into the definition of an organism, it's again just a matter of definition. There's, however, no doubt that the Earth is yet another example of a complex system giving rise to emergent properties, which is why it allows us to refer to it as an organism or as an alive entity sometimes.&lt;/p&gt;&#xA;&lt;p&gt;See also: &lt;a href=&quot;https://en.wikipedia.org/wiki/Self-organization&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Self-organization&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Complexity&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Complexity&lt;/a&gt;. Again these concepts are commonly associated with alive organisms but are not exclusive to them. I think the problem here might be that, although these properties are not only of alive organisms, they are many times among the characteristics that we use to define what life is. Again, this is mostly a matter of definition.&lt;/p&gt;&#xA;" OwnerUserId="21881" LastActivityDate="2021-02-22T13:18:43.203" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20870" PostTypeId="1" CreationDate="2021-02-23T12:30:58.777" Score="3" ViewCount="814" Body="&lt;p&gt;What is the difference between 3-dimensional cleavage and cubic cleavage?&lt;/p&gt;&#xA;&lt;p&gt;I think, they are the same, but I am not sure about if I was right or not.&lt;/p&gt;&#xA;" OwnerUserId="21901" LastEditorUserId="6016" LastEditDate="2021-02-23T13:45:41.363" LastActivityDate="2021-02-24T21:26:33.020" Title="Cleavage of minerals" Tags="|geology|mineralogy|minerals|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20871" PostTypeId="1" CreationDate="2021-02-23T16:13:20.230" Score="3" ViewCount="1138" Body="&lt;p&gt;I am using ERA5 data to drive the land surface model. One of the forcing required by LSM is specific humidity. We want to use the 2-m specific humidity. So how can I calculate the specific humidity based on dew point at 2 meters, surface pressure at 2 meters and temperature at 2 meters? I saw in ERA5 documentation we can calculate the 'saturated specific humidity' by some equations (&lt;a href=&quot;https://confluence.ecmwf.int/display/CKB/ERA5%3A+data+documentation#ERA5:datadocumentation-Computationofnear-surfacehumidityandsnowcover&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://confluence.ecmwf.int/display/CKB/ERA5%3A+data+documentation#ERA5:datadocumentation-Computationofnear-surfacehumidityandsnowcover&lt;/a&gt;).&#xA;&lt;a href=&quot;https://i.stack.imgur.com/qPpwO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qPpwO.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;But how can I get the specific humidity?&lt;/p&gt;&#xA;&lt;p&gt;Thanks and hope for your early reply!&lt;/p&gt;&#xA;" OwnerUserId="14056" LastActivityDate="2021-06-05T11:48:25.163" Title="How to calculate the specific humidity based on the saturated specific humidity?" Tags="|meteorology|climate-models|humidity|land-surface|land-surface-models|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20872" PostTypeId="2" ParentId="20871" CreationDate="2021-02-23T16:37:05.837" Score="1" Body="&lt;p&gt;The answer is easy. Replace &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; with &lt;span class=&quot;math-container&quot;&gt;$T_d$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$T_d$&lt;/span&gt; is the dewpoint temperature.&lt;/p&gt;&#xA;&lt;p&gt;I will say I am not all that familiar with those equations, but that is besides the point.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-02-23T16:37:05.837" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20873" PostTypeId="1" AcceptedAnswerId="20874" CreationDate="2021-02-23T17:37:05.993" Score="2" ViewCount="102" Body="&lt;p&gt;I am a scuba diver, with a big idea that would require me to map various dive sites as I went to them and dove in them. The typical size and other implications of sonar technology would essentially render this impossible.&lt;/p&gt;&#xA;&lt;p&gt;So I thought, would it be possible to use ultrasound instead? This would theoretically require a device that could, instead of seeing through the warm gel that hospitals use, see through cold ocean water. I've done some research but have not gotten a definitive answer, which is understandable since no one has asked the question.&lt;/p&gt;&#xA;&lt;p&gt;And, secondly, if ultrasound is not possible, what else is typically (or not typically) used in oceanography besides sonar?&lt;/p&gt;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;" OwnerUserId="21903" LastActivityDate="2021-02-25T14:51:42.477" Title="Would ultrasound be a valid method of mapping ocean floors given the perceived &quot;gel&quot; is ocean water?" Tags="|oceanography|models|water|mapping|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20874" PostTypeId="2" ParentId="20873" CreationDate="2021-02-23T18:56:48.477" Score="2" Body="&lt;p&gt;It seems that &lt;a href=&quot;http://resource.npl.co.uk/acoustics/techguides/seaabsorption/&quot; rel=&quot;nofollow noreferrer&quot;&gt;attenuation is much greater at ultrasound frequencies&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;50 khz   12-15 dB/km&#xA;0.5khz   0.024 dB/km&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;It depends on what distance and resolution you need.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2021-02-23T18:56:48.477" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20875" PostTypeId="1" AcceptedAnswerId="20882" CreationDate="2021-02-23T22:59:12.527" Score="1" ViewCount="123" Body="&lt;p&gt;Phase change of water at different pressures and temperatures tell us that with no atmospheric pressure 200 Kelvin (minus 73 Celcius) is enough to turn ice into vapor directly&lt;/p&gt;&#xA;&lt;p&gt;Wouldn't that suggest that solar insolation at the distance of earth to the sun heating potential is enough to kickstart the hypothetical ice planet to a waterworld with an atmosphere? Even when averaging day/night?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/91JS8.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/91JS8.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21841" LastEditorUserId="21841" LastEditDate="2021-02-24T14:01:01.897" LastActivityDate="2021-02-24T23:27:30.933" Title="Is it possible to kickstart an hypothetical frozen earth with 0.6 ice albedo to an earth with an atmosphere, with just the sun at current distance?" Tags="|climate-change|geophysics|climate|climatology|thermodynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20876" PostTypeId="1" AcceptedAnswerId="22350" CreationDate="2021-02-24T04:44:54.670" Score="3" ViewCount="152" Body="&lt;p&gt;Suppose you have a wave heading towards the beach, and under the water the surface rises suddenly then drops again back to the typical average slope of the coastline, does this have a muting affect on the water even if the rise in terrain under the wave is completely submerged?&lt;/p&gt;&#xA;&lt;p&gt;A crude drawing of what I mean:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HmUHO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HmUHO.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Would this obstacle cause the wave to increase in height or have a dampening affect on the wave? Would it have to penetrate the surface in order to have any affect on the wave's energy and momentum in this case?&lt;/p&gt;&#xA;" OwnerUserId="21907" LastActivityDate="2021-06-05T11:13:18.393" Title="Are ocean waves diminished, enhanced or unaffected by underwater obstacles" Tags="|oceanography|waves|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20877" PostTypeId="1" AcceptedAnswerId="20879" CreationDate="2021-02-24T15:42:49.613" Score="4" ViewCount="3847" Body="&lt;p&gt;My question deals with the northern hemisphere only, obviously. It seems to me that January and February are the coldest months of the year. Water temperature is even more 'retarded': the seas are coldest in February and March. Since 21 December is the shortest day of the year, why isn't (the end of) December the coldest time of the year, both in air and water temperature?&lt;/p&gt;&#xA;" OwnerUserId="21916" LastActivityDate="2021-02-25T03:20:26.263" Title="Why are January and February the coldest months although 21 December is the shortest day?" Tags="|meteorology|climate|temperature|water|" AnswerCount="3" CommentCount="5" ClosedDate="2021-02-25T06:46:28.910" ContentLicense="CC BY-SA 4.0" />
  <row Id="20878" PostTypeId="2" ParentId="20877" CreationDate="2021-02-24T15:52:41.553" Score="7" Body="&lt;p&gt;Short answer: air, land and water take a while to cool down (or rise in temperature; we see the same thing happening with July and August being the warmest months on average – not June, while June 21st is the longest day). In December, the fall just ended, and everything is relatively warm.&lt;/p&gt;&#xA;&lt;p&gt;Also, depending on how far North you go, the difference between day length in December, January and February isn't that much. See this graph from &lt;a href=&quot;https://en.wikipedia.org/wiki/Daytime#/media/File:Hours_of_daylight_vs_latitude_vs_day_of_year_cmglee.svg&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://svgshare.com/i/URQ.svg&quot; alt=&quot;&quot; /&gt;&lt;/p&gt;&#xA;" OwnerUserId="2958" LastEditorUserId="2958" LastEditDate="2021-02-24T16:01:30.707" LastActivityDate="2021-02-24T16:01:30.707" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20879" PostTypeId="2" ParentId="20877" CreationDate="2021-02-24T17:55:16.670" Score="5" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Why are January and February the coldest months although 21 December is the shortest day?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;For the same reasons that the warmest part of the day generally occurs hours after noon. The daytime temperature only can start decreasing after the outgoing thermal radiation exceeds the incoming solar radiation. Another reason is that water, ground, and even the atmosphere have significant thermal mass.&lt;/p&gt;&#xA;&lt;p&gt;During winter, the Earth continues cooling after December 21 because the average outgoing thermal radiation remains greater than the incoming solar radiation. The huge thermal mass means that winter is centered around mid to late January rather than around December 21. The thermal mass results in a lag in the response of the system.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2021-02-24T17:55:16.670" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20880" PostTypeId="2" ParentId="20870" CreationDate="2021-02-24T21:26:33.020" Score="1" Body="&lt;p&gt;The short answer: &lt;em&gt;cubic cleavage&lt;/em&gt; is a specific example of &lt;em&gt;3D cleavage&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;A cleavage plane is a direction along a crystal splits &lt;em&gt;preferentially&lt;/em&gt; when exposed to mechanical stress.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;3D crystals are objects where the spatial arrangement of atoms is described in  a parallelepiped (a unitcell) with three outer dimensions &lt;span class=&quot;math-container&quot;&gt;$\vec{a}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\vec{b}$&lt;/span&gt;, and &lt;span class=&quot;math-container&quot;&gt;$\vec{c}$&lt;/span&gt;.  The crystal literally builds by translating this unit cell along &lt;span class=&quot;math-container&quot;&gt;$\vec{a}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\vec{b}$&lt;/span&gt;, and &lt;span class=&quot;math-container&quot;&gt;$\vec{c}$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The relative lengths of &lt;span class=&quot;math-container&quot;&gt;$\vec{a}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\vec{b}$&lt;/span&gt;, and &lt;span class=&quot;math-container&quot;&gt;$\vec{c}$&lt;/span&gt; and the angles these vectors enclose define the outer symmetry of this unit cell.  Any of the following seven crystal classes is possible: triclinic, monoclinic, orthorhombic, tetragonal, rhombohedral, hexagonal, and cubic.  In this set, starting from triclinic and moving to cubic, the inherent symmetry increases.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;With &lt;span class=&quot;math-container&quot;&gt;$\vec{a}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\vec{b}$&lt;/span&gt;, and &lt;span class=&quot;math-container&quot;&gt;$\vec{c}$&lt;/span&gt;, equally crystallographic planes may be defined; &lt;em&gt;some&lt;/em&gt; of them parallel to / coincide with the cleavage planes observed at macroscopic scale.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Thus, as listed e.g., in &lt;a href=&quot;https://en.wikipedia.org/wiki/Cleavage_(crystal)#Types_of_cleavage&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; you may discern:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Basal or pinacoidal cleavage occurs when there is only one cleavage plane. Graphite has basal cleavage. Mica (like muscovite or biotite) also has basal cleavage; this is why mica can be peeled into thin sheets.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Cubic cleavage occurs when there are three cleavage planes intersecting at 90 degrees. Halite (or salt) has cubic cleavage, and therefore, when halite crystals are broken, they will form more cubes.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Octahedral cleavage occurs when there are four cleavage planes in a crystal. Fluorite exhibits perfect octahedral cleavage. Octahedral cleavage is common for semiconductors. Diamond also has octahedral cleavage.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Rhombohedral cleavage occurs when there are three cleavage planes intersecting at angles that are not 90 degrees. Calcite has rhombohedral cleavage.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Prismatic cleavage occurs when there are two cleavage planes in a crystal. Spodumene exhibits prismatic cleavage.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Dodecahedral cleavage occurs when there are six cleavage planes in a crystal. Sphalerite has dodecahedral cleavage.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Intentionally, the description above was constrained to 3D crystals which eventually are (typically) described in one of 230 3D space groups. Note, there equally are seven &lt;a href=&quot;https://www.iucr.org/education/pamphlets/21/supplement&quot; rel=&quot;nofollow noreferrer&quot;&gt;planar space groups&lt;/a&gt;, and a growing body of work about &lt;a href=&quot;https://journals.iucr.org/d/issues/2000/10/00/ba0045/&quot; rel=&quot;nofollow noreferrer&quot;&gt;2D crystals&lt;/a&gt;, too.&lt;/p&gt;&#xA;" OwnerUserId="18990" LastActivityDate="2021-02-24T21:26:33.020" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20882" PostTypeId="2" ParentId="20875" CreationDate="2021-02-24T23:27:30.933" Score="2" Body="&lt;p&gt;The answer is &lt;strong&gt;no&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Explanation&lt;/strong&gt;:&lt;/p&gt;&#xA;&lt;p&gt;No atmosphere is equivalent to all molecules being able to evade to space (This happens on planets with low gravitational force). Thus also &lt;span class=&quot;math-container&quot;&gt;$H_2O$&lt;/span&gt; molecules will evade and I guess that many molecules already evaded during the frozen state of the planet due to &lt;a href=&quot;https://en.wikipedia.org/wiki/Sublimation_(phase_transition)&quot; rel=&quot;nofollow noreferrer&quot;&gt;sublimation&lt;/a&gt;. So this could be the end of this answer.&lt;/p&gt;&#xA;&lt;p&gt;But let's suppose for a moment, even if it is not realistic, that an atmosphere could form. Top of atmosphere power received from the sun is around &lt;span class=&quot;math-container&quot;&gt;$S_0 = 1368 \, \frac{\text{W}}{\text{m}^2} $&lt;/span&gt; (&lt;span class=&quot;math-container&quot;&gt;$S_0$&lt;/span&gt; being the solar constant). Assuming earth is a blackbody we can equate power received from the sun and power radiated from the hypothetical earth (see also &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stefan-Boltzmann law&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$S_0(1-\alpha) \pi r^2 = \sigma T^4 4 \pi r^2$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\alpha = 0.6$&lt;/span&gt; is the albedo, &lt;span class=&quot;math-container&quot;&gt;$\sigma = 5.67 \cdot 10^{-8}$&lt;/span&gt; is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_constant&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stefan-Boltzmann constant&lt;/a&gt;, &lt;span class=&quot;math-container&quot;&gt;$\pi = 3.1415$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; is earths surface temperature and &lt;span class=&quot;math-container&quot;&gt;$r = 6371 \, \text{km}$&lt;/span&gt; is earths radius. Simplifying and rearranging yields&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$T = \left(\frac{S_0(1-\alpha)}{4\sigma}\right)^{\frac{1}{4}} \approx 222 \, \text{K} = -51.15°\text{C}$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Taking a look at the phase diagram you provided, we see that at &lt;span class=&quot;math-container&quot;&gt;$222 \, \text{K}$&lt;/span&gt; and low pressure water naturally occurs as gas. Given the assumption that an atmosphere could indeed form (for some magical reason someone increases gravtiy) the answer is &lt;strong&gt;yes&lt;/strong&gt; an atmosphere could form.&lt;/p&gt;&#xA;" OwnerUserId="18833" LastActivityDate="2021-02-24T23:27:30.933" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20883" PostTypeId="2" ParentId="7097" CreationDate="2021-02-24T23:57:50.493" Score="1" Body="&lt;p&gt;Global average temperatures are a convenient metric for finding evidence of global climate change, mostly based on examination of weather station and shipboard temperature records. If global climate is warming or cooling we can confidently expect that global average temperature to show change - with the amount of temperature change a reliable indicator of how much the overall heat balance of the world changes. It does not exist in isolation but relies on wider ranging observation and understanding of climate and weather processes.&lt;/p&gt;&#xA;&lt;p&gt;But other methods are used, such as microwave sounding from satellites, from which temperatures in the atmosphere at various depths can be calculated; MSU derived global average temperatures give very nearly the same warming trend as from weather station based temperatures, but with a stronger response to el Nino Southern Oscillation (ENSO), ie higher temperatures during el Nino events and lower temperature during la Nina events than thermometer based measurement.&lt;/p&gt;&#xA;&lt;p&gt;To get a global average first the placement and reliability of each station is considered; where evidence of inappropriate placement or other problems are found (subject to urban heat, changing locations, changes to surrounds at locations, missing records), those records are omitted and only reliable station data is used. The intent is that the stations used should be representative of the conditions of that location and region, neither exaggerating nor disguising them.&lt;/p&gt;&#xA;&lt;p&gt;Temperatures - usually daily maximum and daily minimum - are averaged for each station and the difference between each daily temperature record and that long term average (anomaly) is found. Usually the globe is divided into smaller, multiple, equal sized areas and the temperature records within each are averaged; this is done so that having a lot of weather stations in some parts of the world and few in other places won't effect results. The averages of all those areas are combined in turn into a single global average.&lt;/p&gt;&#xA;&lt;p&gt;The question of whether the weather in between the stations could be significantly different to what the stations record is a question of wider observation and understanding of weather and climate processes - we do not normally observe weather systems that create big temperature differences in nearby similar places with similar geography. And if great variability were occurring we would not see the regional consistency of temperatures that we do. The greater the number of stations and greater the global coverage, the more reliable a global average will be.&lt;/p&gt;&#xA;&lt;p&gt;Too few sites can distort an average, especially if the conditions at those sites is not typical, but global temperature averages use more than 30,000 station and assuring they are reliable is part of the process. And satellite data, using entirely different methods show essentially the same results.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="18145" LastEditDate="2021-02-26T02:56:40.153" LastActivityDate="2021-02-26T02:56:40.153" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20884" PostTypeId="1" CreationDate="2021-02-25T01:57:46.543" Score="1" ViewCount="287" Body="&lt;p&gt;Coarse grains in a sample of Rhyolite suggest that it formed by ……&#xA;&lt;br&gt;&#xA;A-rapid cooling of molten rock materials at the Earth’s surface.&#xA;&lt;br&gt;&#xA;B-slow cooling of molten rock materials at the Earth’s surface.&#xA;&lt;br&gt;&#xA;C-rapid cooling of molten rock materials below the Earth’s surface.&#xA;&lt;br&gt;&#xA;D-slow cooling of molten rock materials below the Earth’s surface.&lt;/p&gt;&#xA;" OwnerUserId="21901" LastEditorUserId="2470" LastEditDate="2021-02-25T03:16:35.790" LastActivityDate="2023-05-31T06:14:30.137" Title="Coarse grains in a sample of Rhyolite suggest that it formed by" Tags="|geology|igneous|" AnswerCount="2" CommentCount="1" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20885" PostTypeId="2" ParentId="20877" CreationDate="2021-02-25T03:20:26.263" Score="3" Body="&lt;p&gt;I hope this thread is not noticed by our good friends in Australia, who might point out that in their frame of reference January and February are not noted for their coldness!&lt;/p&gt;&#xA;&lt;p&gt;You might be interested to know that there is an astronomical effect which the other answers have overlooked: on about January 6th, the Earth passes through the perihelion point in its orbit -- the point at which the planet's orbit is closest to the Sun.&lt;/p&gt;&#xA;&lt;p&gt;This means that the solar radiation reaching the Earth is at its greatest, per square yard, on that date. This has the effect of increasing the average daily temperature at that time of the year, causing the summer in Australia to be slightly warmer than would otherwise be the case, and the winter in North America and the UK to be slightly less cold than it would otherwise be.&lt;/p&gt;&#xA;&lt;p&gt;The converse is of course true: aphelion occurs in July, when the Earth is at the point in its orbit which is furthest from the Sun. So the Northern hemisphere summer is less warm than it would otherwise be, due to a reduction in the quantity of solar radiation per square yard at that time of year.&lt;/p&gt;&#xA;&lt;p&gt;It seems to be pure chance that the perihelion and aphelion points in the Earth's orbit coincide fairly closely with the dates of the winter solstice and summer solstice, which are due to the Earth's axial tilt. One could speculate that this is not mere chance, and that the events are in fact related; but, for practical purposes, the Earth's orbit is insufficiently eccentric for the difference between perihelion and aphelion to compensate for the axial tilt.&lt;/p&gt;&#xA;&lt;p&gt;Axial tilt determines the amount of heat energy reaching the surface: which is maximised when the surface is at 90 degrees to the incoming solar radiation (orthogonal); and when the radiation has least atmosphere to traverse (which absorbs the energy), due to the Sun being higher above the horizon; and when the hours of daylight are greatest.&lt;/p&gt;&#xA;" OwnerUserId="21921" LastActivityDate="2021-02-25T03:20:26.263" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20886" PostTypeId="1" AcceptedAnswerId="20888" CreationDate="2021-02-25T03:24:39.610" Score="3" ViewCount="564" Body="&lt;p&gt;The Wikipedia &lt;em&gt;disambiguation page&lt;/em&gt; &lt;a href=&quot;https://en.wikipedia.org/wiki/Horseshoe_Lake&quot; rel=&quot;nofollow noreferrer&quot;&gt;Horseshoe lake&lt;/a&gt; lists 31 of them, of which 27 are in the US.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Why are there so many &amp;quot;horseshoe lakes&amp;quot;? Are they usually horseshoe-shaped, (or full of horseshoes)?&lt;/li&gt;&#xA;&lt;li&gt;Are they really mostly in the US? For geological reasons, or are they everywhere but not necessarily named as such (I've made attempts to search google translated &amp;quot;horseshoe lake&amp;quot; in Spanish and Chinese but did not find many)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2021-02-25T16:45:13.340" Title="Why are there so many &quot;horseshoe lakes&quot;, and are they really mostly in the US?" Tags="|terminology|lakes|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20887" PostTypeId="2" ParentId="7097" CreationDate="2021-02-25T09:40:33.190" Score="0" Body="&lt;p&gt;It's the same as if you had to average the temperature of your kitchen comprising a hot oven on one side and a cold window on another, you'd have to divide the kitchen into a grid and get a laser measurement for every square. Check images for Gistemp v4, hadCRUT3, and OMM:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/r0s9L.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/r0s9L.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So it's just an average of weather stations on land and sea, i.e. NASA's program states:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The GISS Surface Temperature Analysis v4 is an estimate of global surface temperature change. Graphs and tables are updated around the middle of every month using current data files from NOAA GHCN v4 (meteorological stations) and ERSST v5 (ocean areas), combined as described in our publications Hansen et al. (2010) and Lenssen et al. (2019). These updated files incorporate reports for the previous month and also late reports and corrections for earlier months.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;i.e. UK's MET office program: &lt;a href=&quot;https://en.wikipedia.org/wiki/HadCRUT&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/HadCRUT&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;i.e. The swiss based OMM, Organisation Météorologique Mondiale, &lt;a href=&quot;https://library.wmo.int/doc_num.php?explnum_id=4220&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://library.wmo.int/doc_num.php?explnum_id=4220&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3315" LastActivityDate="2021-02-25T09:40:33.190" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20888" PostTypeId="2" ParentId="20886" CreationDate="2021-02-25T11:39:59.677" Score="4" Body="&lt;p&gt;Let's get rid of a red herring from the Wikipedia page linked to in the question!&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;Horseshoe Lake, Arizona&lt;/strong&gt;&lt;/em&gt; - is a reservoir created by the Horseshoe dam. Nothing to do with actual horseshoe lakes.&lt;/p&gt;&#xA;&lt;p&gt;The other's lakes listed might be genuine horseshoe lakes, but there are no aerial photographs of them.&lt;/p&gt;&#xA;&lt;p&gt;Generally, horseshoe lakes are &lt;a href=&quot;https://en.wikipedia.org/wiki/Oxbow_lake&quot; rel=&quot;nofollow noreferrer&quot;&gt;oxbow lakes&lt;/a&gt; which is&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;a U-shaped lake that forms when a wide meander of a river is cut off, creating a free-standing body of water. In south Texas, oxbows left by the Rio Grande are called &lt;a href=&quot;https://en.wikipedia.org/wiki/Resaca_(channel)&quot; rel=&quot;nofollow noreferrer&quot;&gt;resacas&lt;/a&gt;. In Australia, oxbow lakes are called &lt;a href=&quot;https://en.wikipedia.org/wiki/Billabong&quot; rel=&quot;nofollow noreferrer&quot;&gt;billabongs&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;A resacas is a&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;former channels of the Rio Grande and are naturally cut off from the river, having no inlet or outlet&lt;/p&gt;&#xA;&lt;p&gt;The Rio Grande's water moves from Colorado to the Gulf of Mexico. Every year during spring, melted snow would flow into the Rio Grande, bringing seasonal flood waters to the most southern tip of Texas.&lt;a href=&quot;https://en.wikipedia.org/wiki/Billabong&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt; Given the overflow of the river's main and distributary channel banks, the Rio Grande would carve new river channels, resacas. When the seasonal flooding ended and the river retreated, the newly formed oxbow lakes remained, creating resacas all throughout the Rio Grande Valley.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In Australia, billabongs are&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;an isolated pond left behind after a river changes course. Billabongs are usually formed when the path of a creek or river changes, leaving the former branch with a dead end. As a result of the arid Australian climate in which these &amp;quot;dead rivers&amp;quot; are often found, billabongs fill with water seasonally but can be dry for a greater part of the year.&lt;/p&gt;&#xA;&lt;p&gt;Billabongs were significant because they held water longer than parts of rivers; it was important for people to identify and name these areas.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In general,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;An oxbow lake forms when a river creates a meander, due to the river's eroding bank. After a long period of time, the meander becomes very curved, and eventually the neck of the meander becomes narrower and the river cuts through the neck, cutting off the meander and forming an oxbow lake.&lt;/p&gt;&#xA;&lt;p&gt;When a river reaches a low-lying plain, often in its final course to the sea or a lake, it meanders widely. In the vicinity of a river bend, deposition occurs on the convex bank (the bank with the smaller radius). In contrast, both lateral erosion and undercutting occur on the cut bank or concave bank (the bank with the greater radius). Continuous deposition on the convex bank and erosion of the concave bank of a meandering river cause the formation of a very pronounced meander with two concave banks getting closer. The narrow neck of land between the two neighboring concave banks is finally cut through, either by lateral erosion of the two concave banks or by the strong currents of a flood. When this happens a new, straighter river channel develops—and an abandoned meander loop, called a cutoff, forms. When deposition finally seals off the cutoff from the river channel, an oxbow lake forms. This process can occur over a time from a few years to several decades, and may sometimes become essentially static.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The naming of oxbow lakes as horseshoe lakes might just be American terminology. When such lakes were being &amp;quot;discovered&amp;quot; and &amp;quot;mapped&amp;quot; most people would have known about horseshoes, but maybe not oxbows so they got named after what they knew.&lt;/p&gt;&#xA;&lt;p&gt;Oxbow lakes do exist elsewhere, they're just not named as horseshoe lakes.&lt;/p&gt;&#xA;&lt;p&gt;The Kanwar Lake Bird Sanctuary in India is one of the largest oxbow lakes in Asia. In the United Kingdom they also occur in the Gower Peninsular of southwest Wales and there is also the Bole and Burton Round in Nottinghamshire.&lt;/p&gt;&#xA;&lt;p&gt;Celestially, there has also been a possible oxbow lake postulated in Saraswati Flumen near &lt;a href=&quot;https://en.wikipedia.org/wiki/Ontario_Lacus&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ontario Lacus&lt;/a&gt; on Saturn's moon Titan.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-02-25T16:45:13.340" LastActivityDate="2021-02-25T16:45:13.340" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20889" PostTypeId="1" AcceptedAnswerId="20916" CreationDate="2021-02-25T11:53:00.433" Score="2" ViewCount="467" Body="&lt;p&gt;The Average Surface Temperature of the Earth is calculated by the following equation:&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\sigma T_s^4=\frac{(1-A)\Omega}{4}+\Delta E$$&lt;/span&gt;&#xA;where,&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$\sigma$&lt;/span&gt;= &lt;em&gt;Stefan-Boltzmann Constant&lt;/em&gt;&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$T_s$&lt;/span&gt;= &lt;em&gt;Average Surface Temperature of Earth&lt;/em&gt;&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt;= &lt;em&gt;Global Albido&lt;/em&gt;&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$\Omega$&lt;/span&gt;= &lt;em&gt;Total Solar Irradiance&lt;/em&gt;&lt;br /&gt;&#xA;And, &lt;span class=&quot;math-container&quot;&gt;$\Delta E$&lt;/span&gt;= &lt;em&gt;Magnitude of Greenhouse Effect&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;The observed average surface temperature of Earth is about &lt;span class=&quot;math-container&quot;&gt;$288K$&lt;/span&gt;, Global Albido as seen by satellites is about &lt;span class=&quot;math-container&quot;&gt;$0.3$&lt;/span&gt; and the total solar irradiance is about &lt;span class=&quot;math-container&quot;&gt;$1370W/m²$&lt;/span&gt;. Putting these values in the above equation, &lt;span class=&quot;math-container&quot;&gt;$\Delta E$&lt;/span&gt; comes out to be about &lt;span class=&quot;math-container&quot;&gt;$150W/m²$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Now, according to &lt;a href=&quot;https://web.viu.ca/krogh/chem302/CHEM%20302%20Practise%20Questions%208%20scanned%20solns.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;&#xA;PDF I found online, the concentration of &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; is related to &lt;span class=&quot;math-container&quot;&gt;$\Delta E$&lt;/span&gt; by the following equation:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\Delta E=133.26+0.044[CO_2]$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;When we put &lt;span class=&quot;math-container&quot;&gt;$\Delta E=150$&lt;/span&gt;, we get the &lt;span class=&quot;math-container&quot;&gt;$[CO_2]=380$&lt;/span&gt; which is the actual concentration of &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; in the atmosphere according to some online sources in ppm. So the above relation seems correct.&lt;/p&gt;&#xA;&lt;p&gt;How was this relation calculated? And, how to calculate such relations for other Greenhouse gases, such as &lt;span class=&quot;math-container&quot;&gt;$H_2O$&lt;/span&gt;?&lt;/p&gt;&#xA;&lt;p&gt;In other words, given the Equation:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\Delta E=x+y[H_2O]$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Find x and y.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;What I noticed&lt;/em&gt;: The coefficient of &lt;span class=&quot;math-container&quot;&gt;$[CO_2]$&lt;/span&gt; in the above mentioned equation is &lt;span class=&quot;math-container&quot;&gt;$0.044$&lt;/span&gt;. And, the molecular mass of &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; is &lt;span class=&quot;math-container&quot;&gt;$44.01 amu $&lt;/span&gt;. So, Molecular mass might be involved in the calculation of &lt;span class=&quot;math-container&quot;&gt;$y$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;My approach&lt;/em&gt;: I focused on finding &lt;span class=&quot;math-container&quot;&gt;$y$&lt;/span&gt; as &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; can be calculated later from the same equation since &lt;span class=&quot;math-container&quot;&gt;$\Delta E$&lt;/span&gt; is known and concentration of &lt;span class=&quot;math-container&quot;&gt;$H_2O$&lt;/span&gt; should be available online. According to my understanding of the Greenhouse effect, &lt;span class=&quot;math-container&quot;&gt;$y$&lt;/span&gt; represents how much energy per unit area does &lt;span class=&quot;math-container&quot;&gt;$1$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$ppm$&lt;/span&gt; of a &lt;span class=&quot;math-container&quot;&gt;$GHG$&lt;/span&gt; can trap and transmit down to Earth. I tried searching online for some data on the same, but could find none.&lt;/p&gt;&#xA;&lt;p&gt;Please throw some light on the topic.&lt;/p&gt;&#xA;&lt;p&gt;Thank You.&lt;/p&gt;&#xA;" OwnerUserId="21924" LastEditorUserId="21924" LastEditDate="2021-02-25T11:58:51.570" LastActivityDate="2021-02-27T11:09:43.107" Title="Relation between Magnitude of Greenhouse Effect and the Concentration of GHGs like $CO_2$" Tags="|meteorology|atmosphere|temperature|homework|greenhouse-gases|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20890" PostTypeId="2" ParentId="565" CreationDate="2021-02-25T13:55:22.653" Score="1" Body="&lt;h1&gt;No&lt;/h1&gt;&#xA;&lt;p&gt;The Earth is not a living thing and therefore not an &lt;a href=&quot;https://www.google.com/search?q=organism&amp;amp;rlz=1CAJIKU_enUS931&amp;amp;oq=Orga&amp;amp;aqs=chrome.1.69i57j0i433l5j69i60l2.3113j1j7&amp;amp;sourceid=chrome&amp;amp;ie=UTF-8&amp;amp;safe=active&amp;amp;ssui=on&amp;amp;surl=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;organism.&lt;/a&gt; Life is defined by several things:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Growth&lt;/li&gt;&#xA;&lt;li&gt;Reproduction&lt;/li&gt;&#xA;&lt;li&gt;DNA/RNA&lt;/li&gt;&#xA;&lt;li&gt;Oxygen Exchange (Except for some organisms)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;It is valid to say that earth is giant habitat for life. Earth can be described as a huge magnet and a hot rock orbiting a giant sun that will one day wipe out life on Earth. All human life is projected to be extinct between 5,100 and 7.8 million years from now &lt;a href=&quot;https://www.google.com/search?q=when%20will%20humans%20go%20extinct&amp;amp;rlz=1CAJIKU_enUS931&amp;amp;oq=when%20will%20hu&amp;amp;aqs=chrome.1.69i57j0l3j0i131i433j0l5.6631j0j7&amp;amp;sourceid=chrome&amp;amp;ie=UTF-8&amp;amp;safe=active&amp;amp;ssui=on&amp;amp;surl=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21926" LastEditorUserId="21926" LastEditDate="2021-02-25T19:00:45.723" LastActivityDate="2021-02-25T19:00:45.723" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20891" PostTypeId="2" ParentId="20873" CreationDate="2021-02-25T14:51:42.477" Score="1" Body="&lt;p&gt;Optical LIDAR systems for marine use are being developed and are being used for accurate mapping of archaeological remains under water. See &lt;a href=&quot;https://optics.org/news/8/3/26&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://optics.org/news/8/3/26&lt;/a&gt;. However if a sonar is too big and impractical, I imagine oceanographic LIDAR is similarly out of scope.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2021-02-25T14:51:42.477" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20899" PostTypeId="1" AcceptedAnswerId="20903" CreationDate="2021-02-25T23:55:30.567" Score="1" ViewCount="935" Body="&lt;p&gt;Correct me if I'm wrong, but most rivers lie where &lt;strong&gt;the water table protrudes into open air.&lt;/strong&gt; In other words, the water table level is exactly the same as the river water level. (&lt;a href=&quot;https://en.wikipedia.org/wiki/Water_table&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; has a good diagram.)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jvY5r.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jvY5r.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So now the question is, what happens if you channelize the river with impermeable walls and bed? E.g., &lt;a href=&quot;https://en.wikipedia.org/wiki/Los_Angeles_River&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Los Angeles River&lt;/a&gt;, which has concrete walls.&lt;/p&gt;&#xA;&lt;p&gt;What happens to the isolated water table now? It is no longer free to drain into the river, so where does it go? Does it drain away more into the ground? Does it stay more saturated than normal until evaporation? And doesn't this produce dangerous ground conditions and bad environmental effects?&lt;/p&gt;&#xA;&lt;p&gt;Water needs to follow some cycle, or it will just fill up more and more till the whole region is a flooded lake or ocean. So I'm trying to understand the water cycle in this case.&lt;/p&gt;&#xA;" OwnerUserId="2733" LastEditorUserId="6258" LastEditDate="2021-02-26T07:26:23.443" LastActivityDate="2021-02-26T14:00:14.003" Title="What effect does river channelization have on the surrounding water table?" Tags="|hydrology|rivers|water-table|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20902" PostTypeId="1" CreationDate="2021-02-26T11:19:57.663" Score="3" ViewCount="185" Body="&lt;p&gt;I understand that 40% rel. hum. at 0 °C is less absolute humidity than 40% at 20 °C. However, assume that we have 2&lt;span class=&quot;math-container&quot;&gt;$~m^3$&lt;/span&gt; of air. Both are 40% humid at 20 °C. Now we exchange 1&lt;span class=&quot;math-container&quot;&gt;$~m^3$&lt;/span&gt; with air that is 40% humid at 0°C. Then according to &lt;a href=&quot;https://wiki.unece.org/download/attachments/23101992/image2014-5-19%2010%3A38%3A41.png?version=1&amp;amp;modificationDate=1400488842518&amp;amp;api=v2&quot; rel=&quot;nofollow noreferrer&quot;&gt;this picture&lt;/a&gt; we should get 7&lt;span class=&quot;math-container&quot;&gt;$~g\, m^{-3}$&lt;/span&gt; and 2&lt;span class=&quot;math-container&quot;&gt;$~g\, m^{-3}$&lt;/span&gt; of absolute humidity for each part. So that's 4.5&lt;span class=&quot;math-container&quot;&gt;$~g\, m^{-3}$&lt;/span&gt; on average. Now the temperature should be 10 °C (right?). Then, 4.5&lt;span class=&quot;math-container&quot;&gt;$~g\, m^{-3}$&lt;/span&gt; means a relative humidity of around 50%! So why does relative humidity drop in reality? Is it because the temperature would actually be higher somehow?&lt;/p&gt;&#xA;" OwnerUserId="21933" LastEditorUserId="106" LastEditDate="2021-02-27T13:07:38.570" LastActivityDate="2021-04-01T18:56:03.400" Title="Why does relative humidity drop if I open the window in winter? What about the temperature drop?" Tags="|temperature|humidity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20903" PostTypeId="2" ParentId="20899" CreationDate="2021-02-26T11:53:25.263" Score="3" Body="&lt;p&gt;The concept of rivers being the outcrop of an aquifer at the surface is a useful generalization, but tends to simplify the real world.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The water level in a river can be higher than the water table in an aquifer. We would describe the river as 'losing' water and it would recharge the aquifer. So in that case channelization would reduce aquifer recharge and potentially lower the water table. As an example irrigation canals in arid areas are often quite leaky. Projects to line the canals to reduce leakage have frequently had the unintended consequence of cutting off local recharge to aquifers used by farmers adjacent to the canal.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;If the water level in the aquifer is higher than the river we describe it as a 'gaining' river. Channelization would reduce river flow and lead to higher water tables in the aquifer. The consequence of the higher water tables might be increased spring or river flow in another part of the aquifer - or in the worst case emergence of water adjacent to the channelized section waterlogging the ground. The extreme case of filling up a whole region is improbable, as once levels rise enough the water will just flow back into the channel, or further rise will be balanced by evaporation from open water.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Stretches of river may change from losing to gaining, and vice versa, seasonally, or in response to changes in geology or topography over quite short distances. Natural river beds are often not seamlessly connected to the aquifers they run over; muds and silts on the river bed can reduce permeability and effectively cause natural channelization. Equally artificial channelization is rarely 100% effective and leak proof.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="21672" LastEditorUserId="21672" LastEditDate="2021-02-26T14:00:14.003" LastActivityDate="2021-02-26T14:00:14.003" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20904" PostTypeId="2" ParentId="20791" CreationDate="2021-02-26T12:54:21.400" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;How on “Earth” can you make all those measurements of Earth forming?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;One word: Zircons.&lt;/p&gt;&#xA;&lt;p&gt;Zircons rank very high amongst the techniques used to measure the age of the Earth, and the age at which the Earth later cooled down. One of the key elements in zircons is zirconium. There are other elements that have similar chemical characteristics to zirconium. One of these is uranium. Both uranium 235 and uranium 238 eventually decay to lead. Lead is extremely incompatible with zirconium from a chemical perspective. All of the lead in a zircon could only have resulted from radioactive decay.&lt;/p&gt;&#xA;&lt;p&gt;The question focuses on the &amp;quot;boring billion&amp;quot; years in the Earth's history that occurred well after the Earth formed (over three billion years after the Earth formed). Zircons were key in that analysis as well. There are other elements other than uranium that are chemically compatible with zirconium. One of these is europium. The presence or absence of europium in zircons indicates whether or not mountains were eroding at the time those zircons formed. The ratio of uranium to lead in those zircons indicates how old those zircons are.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2021-02-26T12:54:21.400" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20905" PostTypeId="2" ParentId="20782" CreationDate="2021-02-26T13:29:53.850" Score="1" Body="&lt;p&gt;&lt;strong&gt;&lt;a href=&quot;https://www.classcentral.com/course/swayam-metamorphic-petrology-thermodynamics-14197&quot; rel=&quot;nofollow noreferrer&quot;&gt;ClassCentral.com&lt;/a&gt;, &lt;a href=&quot;https://www.southalabama.edu/geography/allison/gy303/GY303Lectures.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;SouthAlabama.Edu&lt;/a&gt;, &lt;a href=&quot;https://www.ndsu.edu/pubweb/%7Esainieid/pet/pet-links.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ndsu.com&lt;/a&gt;, &lt;a href=&quot;https://ocw.mit.edu/courses/earth-atmospheric-and-planetary-sciences/12-109-petrology-fall-2005/lecture-notes/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ocw.mit.edu&lt;/a&gt;&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;You can learn a lot from these sites.&lt;/p&gt;&#xA;" OwnerUserId="21926" LastActivityDate="2021-02-26T13:29:53.850" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20907" PostTypeId="1" CreationDate="2021-02-26T15:08:02.583" Score="1" ViewCount="228" Body="&lt;p&gt;I am working on a seismology assignment and it starts with the fundamentals of seismology such as the wave equation, the slowness... such as the question below:&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;write an equation describing the horizontal slowness (reciprocal of the velocity). This becomes a vector quantity for propagation in multiple directions.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;I haven't fully grasped these concepts yet. And I looked around for lecture notes and this is what I found:&#xA;&lt;a href=&quot;https://ocw.mit.edu/courses/earth-atmospheric-and-planetary-sciences/12-510-introduction-to-seismology-spring-2010/lecture-notes/lec5.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;MIT-introduction to seismology&lt;/a&gt; and &lt;a href=&quot;https://i.stack.imgur.com/7obCU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7obCU.png&quot; alt=&quot;continuum mechanics lecture notes&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I am not sure which one is the answer to this question or what is even the difference between the two because they both seem to represent the slowness&lt;/p&gt;&#xA;" OwnerUserId="21934" LastActivityDate="2021-02-26T15:08:02.583" Title="Horizontal slowness in seismology" Tags="|seismology|waves|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20908" PostTypeId="1" AcceptedAnswerId="20909" CreationDate="2021-02-26T15:21:59.703" Score="-1" ViewCount="68" Body="&lt;p&gt;Can wind/air that is moving at average speeds be slowed down by the cause of &lt;strong&gt;Friction&lt;/strong&gt;? Also, Can Air bubbles in water be slowed down because of Friction? &lt;em&gt;Please cite your sources.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="21926" LastActivityDate="2021-02-26T20:54:57.033" Title="Can air be slowed down by Fricton?" Tags="|hydrology|water|wind|fluid-dynamics|" AnswerCount="1" CommentCount="4" ClosedDate="2021-02-27T11:15:16.233" ContentLicense="CC BY-SA 4.0" />
  <row Id="20909" PostTypeId="2" ParentId="20908" CreationDate="2021-02-26T20:54:57.033" Score="2" Body="&lt;p&gt;Air is affected by friction. &lt;a href=&quot;https://journals.ametsoc.org/search?q1=friction&amp;amp;searchBtn=&quot; rel=&quot;nofollow noreferrer&quot;&gt;A brief search of AMS journals shows over 14,000 times friction is mentioned.&lt;/a&gt; How it is manifested in the equations that describe the atmosphere is complicated.&lt;/p&gt;&#xA;&lt;p&gt;Let's think of wind as 'air moving' or perhaps space moving which air occupies. At some point, &lt;a href=&quot;https://glossary.ametsoc.org/wiki/Aerodynamic_roughness_length&quot; rel=&quot;nofollow noreferrer&quot;&gt;called the roughness length&lt;/a&gt;, the wind is 0 m/s (or knots or mph). If such a thing does not exist, then the earth would move with the wind (which is legitimate thing with blowing dust/snow). Concerning this, &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S1674984716300301&quot; rel=&quot;nofollow noreferrer&quot;&gt;the atmosphere produces a frictional torque&lt;/a&gt; on the earth, and vice-versa. A metric to gauge the influence of friction is the friction velocity. Perhaps, most notably, friction is a major cause on why &lt;a href=&quot;http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/fric.rxml&quot; rel=&quot;nofollow noreferrer&quot;&gt;the surface wind and geostrophic wind are not the same.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Regarding air bubbles in water, I would say it has &lt;em&gt;some&lt;/em&gt; effect, but is probably not the dominant effect. That is, unless you consider viscosity to be a manifestation of friction (&lt;a href=&quot;http://galileo.phys.virginia.edu/classes/152.mf1i.spring02/Viscosity.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;which it is&lt;/a&gt;). If you consider viscosity to be a form of friction, then air has friction within itself. Viscosity is often considered to be so small that it is ignorable, unless you are dealing with micrometeorology or ocean dynamics (see &lt;a href=&quot;https://en.wikipedia.org/wiki/Ekman_transport&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ekman transport&lt;/a&gt;). But even in micrometeorology, the few times true viscosity (not eddy viscosity) is not ignorable is within the &lt;a href=&quot;https://en.wikipedia.org/wiki/Turbulence_kinetic_energy&quot; rel=&quot;nofollow noreferrer&quot;&gt;dissipation of turbulent kinetic energy.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-02-26T20:54:57.033" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20910" PostTypeId="1" AcceptedAnswerId="20912" CreationDate="2021-02-26T22:34:49.400" Score="5" ViewCount="229" Body="&lt;p&gt;Maybe a simple question, but if sulfur hexafluoride is 6 times heavier than air then how does it get into the high atmosphere. All be it in low quantities now, but there is a large stock of the stuff in potentially vulnerable and prevalent infrastructure such as substations of the electricity grid. If there was a much larger leak of the chemical than is now observed would we expect it to reach the upper atmosphere to become a dangerous greenhouse gas at that position in the atmosphere... as i understand potent ghg's induce greater warming when high in the atmosphere. Anyone know more about this? its mode of transport there, what activities are getting it up there? Ive done some research on existing and past growing concentrations but wonder if its Global warming potential is dangerous unless it can actually accumulate significantly high in the atmosphere?&lt;/p&gt;&#xA;" OwnerUserId="21231" LastActivityDate="2021-02-27T02:19:12.763" Title="sulfur hexafluroide as a greenhouse gas and its atmospheric journey" Tags="|greenhouse-gases|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20911" PostTypeId="1" CreationDate="2021-02-27T00:37:26.710" Score="5" ViewCount="234" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MJgwH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MJgwH.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;CO&lt;sub&gt;2&lt;/sub&gt; absorbs around the 15 microns wavelenght or wavenumber 650, and radiates in the same but also a somewhat wider range.&lt;/p&gt;&#xA;&lt;p&gt;However, the top layer of the oceans seem to also convert that spectrum range. According to a paper I found there is some increased absorbance of infrared in water around the 650 wave number.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.acamedia.info/sciences/J_G/envrad/microwaves/Water_absorption_spectrum.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.acamedia.info/sciences/J_G/envrad/microwaves/Water_absorption_spectrum.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Can it in a substantial way contribute to a conversion of that spectrum range to other spectra?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Added text for asked clarification.&lt;/p&gt;&#xA;&lt;p&gt;We know co2 radiation is somewhat wider than absorption. I am asking if that is the same in the first few microns depth in water (few molecules of the top layer). Absorption of infrared in water does the same? And the total (combined with co2) is substantial enough to explain the missing gap around 15 microns wavelenght in the outgoing radiation of the earth?&lt;/p&gt;&#xA;" OwnerUserId="21841" LastEditorUserId="21841" LastEditDate="2021-03-08T00:51:53.413" LastActivityDate="2021-03-08T00:51:53.413" Title="Can the absorbtion of infrared around the 650 wavenumber in water be a substantial cause of converting that spectrum range into other spectra?" Tags="|atmosphere|climate|co2|climatology|atmospheric-radiation|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="20912" PostTypeId="2" ParentId="20910" CreationDate="2021-02-27T02:19:12.763" Score="2" Body="&lt;p&gt;Carbon dioxide is heavier than air but is found in nearly equal proportions throughout the well-mixed portion of the atmosphere. Xenon is much heavier than air, almost as heavy as sulfur hexaflouride, but it too is found in nearly equal proportions throughout the well-mixed portion of the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;Turbulence is what makes the well-mixed portion of the atmosphere be well-mixed. It is only in the uppermost layers of the atmosphere, where the air is very thin, that turbulence fails to keep things well-mixed. The turbopause, which marks the border between the well-mixed lower portions of the atmosphere and heterogenous upper portions of the atmosphere, is about 100 km above the surface. The stratosphere is only 10 to 50 km above the surface, so it is well within the well-mixed portion of the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2021-02-27T02:19:12.763" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20913" PostTypeId="2" ParentId="19580" CreationDate="2021-02-27T09:16:33.430" Score="5" Body="&lt;p&gt;NASA &lt;a href=&quot;https://www.nasa.gov/mission_pages/station/research/experiments/explorer/index.html&quot; rel=&quot;noreferrer&quot;&gt;Space Station Research Explorer&lt;/a&gt; allows to filter experiments by expedition and category. A &lt;a href=&quot;https://www.nasa.gov/mission_pages/station/research/experiments/explorer/search.html?#q=&amp;amp;i=63&amp;amp;p=&amp;amp;c=Earth&amp;amp;g=Investigation&amp;amp;s=&quot; rel=&quot;noreferrer&quot;&gt;query&lt;/a&gt; for expedition 63 and the &amp;quot;Earth and space science&amp;quot; category yields the following 17 results (as of 27 February 2021):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;AMS-02 (Alpha Magnetic Spectrometer - 02)&lt;/li&gt;&#xA;&lt;li&gt;ASIM (Atmosphere-Space Interactions Monitor)&lt;/li&gt;&#xA;&lt;li&gt;ISS-CREAM (Cosmic Ray Energetics and Mass for the International Space Station)&lt;/li&gt;&#xA;&lt;li&gt;CEO (Crew Earth Observations)&lt;/li&gt;&#xA;&lt;li&gt;iSIM (Demonstration of integrated Standard Imager for Microsatellites)&lt;/li&gt;&#xA;&lt;li&gt;ECOSTRESS (ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station)&lt;/li&gt;&#xA;&lt;li&gt;Tanpopo-2 (ExHAM-Astrobiology Japan-2)&lt;/li&gt;&#xA;&lt;li&gt;GEDI (Global Ecosystem Dynamics Investigation)&lt;/li&gt;&#xA;&lt;li&gt;HISUI (Hyper-Spectral Imager Suite)&lt;/li&gt;&#xA;&lt;li&gt;NICER (Neutron Star Interior Composition Explorer)&lt;/li&gt;&#xA;&lt;li&gt;OCO-3 (Orbiting Carbon Observatory-3)&lt;/li&gt;&#xA;&lt;li&gt;STP-H6-NIRAC (Space Test Program-Houston 6-Near InfraRed Airglow Camera)&lt;/li&gt;&#xA;&lt;li&gt;STP-H5 FPS (STP-H5-Fabry Perot Spectrometer for Methane)&lt;/li&gt;&#xA;&lt;li&gt;STP-H5 LIS (STP-H5-Lightning Imaging Sensor)&lt;/li&gt;&#xA;&lt;li&gt;SAGE III-ISS (Stratospheric Aerosol and Gas Experiment III-ISS)&lt;/li&gt;&#xA;&lt;li&gt;SPOC (The Spectral Ocean Color (SPOC) Satellite)&lt;/li&gt;&#xA;&lt;li&gt;Total &amp;amp; Spectral Solar Irradiance Sensor (TSIS) (Total and Spectral Solar Irradiance Sensor)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2021-02-27T09:16:33.430" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="20914" PostTypeId="2" ParentId="4822" CreationDate="2021-02-27T09:24:59.493" Score="-1" Body="&lt;p&gt;Present distribution of land masses have occurred due to the movement of tectonic plates. The real reason of the movement of plates is not precisely known, but it is perhaps related with the events that are occurring inside the Earth's interior, there is molten lava where several circles of waves are in continuous movement. There are several cells of such waves. There are two types of areas, one where waves converge, while another where up-moving waves diverge in opposite direction below the crust. In the areas where waves converge, the land mass is concentrated over there. While in areas with diverging waves below, the crust moves away  from there.&lt;/p&gt;&#xA;&lt;p&gt;Land masses have converged around North pole, probably because of these converging waves. This phenomena is geophysically very complex and needs extensive and deep research.&lt;/p&gt;&#xA;" OwnerUserId="21937" LastEditorUserId="2470" LastEditDate="2021-02-27T10:35:20.153" LastActivityDate="2021-02-27T10:35:20.153" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20915" PostTypeId="1" CreationDate="2021-02-27T09:29:32.600" Score="2" ViewCount="105" Body="&lt;p&gt;Wherever I look, I find &amp;quot;Temperature Anamolies&amp;quot; which I assume is an annual temperature change relative to the previous year.&lt;/p&gt;&#xA;&lt;p&gt;If I wanted to find the exact temperatures (based on NASA's accurate forecasts and estimates), can I get them somewhere?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://data.giss.nasa.gov/gistemp/graphs/graph_data/Global_Mean_Estimates_based_on_Land_and_Ocean_Data/graph.txt&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://data.giss.nasa.gov/gistemp/graphs/graph_data/Global_Mean_Estimates_based_on_Land_and_Ocean_Data/graph.txt&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The above link shows the temperature change but if I add them up, the current global temperature comes out somewhere near 21 degrees as opposed to 14 degrees figure I often see everywhere..&lt;/p&gt;&#xA;" OwnerUserId="21938" LastActivityDate="2021-02-27T18:28:24.823" Title="How to get the exact temperature from 1880 to 2020?" Tags="|climate-change|temperature|" AnswerCount="1" CommentCount="15" ClosedDate="2021-02-28T06:31:23.290" ContentLicense="CC BY-SA 4.0" />
  <row Id="20916" PostTypeId="2" ParentId="20889" CreationDate="2021-02-27T11:09:43.107" Score="4" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Δ=133.26+0.044[2]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It’s just a numerical coincidence that the 0.044 looks like the molar mass of CO2.  That equation gives 0.044 * 380 = 16 W/m2, which is the reduction in surface downwelling IR if you remove all the CO2 from the present day atmosphere (e.g., see Table 1 of Zhong and Haigh, 2013, Weather, &lt;a href=&quot;https://doi.org/10.1002/wea.2072&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1002/wea.2072&lt;/a&gt;, &lt;a href=&quot;https://courses.seas.harvard.edu/climate/eli/Courses/global-change-debates/Sources/CO2-saturation/more/Zhong-Haigh-2013.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;pdf&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;Looking at water vapour in the same way exposes some of the limits of the model they’ve set up for this tutorial, which was presumably kept simple just to teach some concepts to their students.  To do the same thing for water vapour as was done for CO2 would require removing 208 W/m2 of greenhouse effect (again, see Table 1 of that article), more than the total greenhouse effect of 150 W/m2 in their model.  The discrepancy is because they have too much solar radiation in the surface energy budget, so the diagnosed greenhouse effect doesn’t have to do as much work to balance a 288 K surface temperature.&lt;/p&gt;&#xA;&lt;p&gt;A more realistic model would exclude the 80 W/m2 of solar radiation absorbed by the atmosphere, leaving an absorbed solar flux at the surface of 160 W/m2.  The balance is then &lt;span class=&quot;math-container&quot;&gt;$390 = 160 + \Delta E$&lt;/span&gt;, so &lt;span class=&quot;math-container&quot;&gt;$\Delta E = 230$&lt;/span&gt; W/m2 and the revised perturbation equation for CO2 is,&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\Delta E = 214 + 0.044[CO2]$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The difficulty with H20 is that, unlike CO2, the concentration of water vapour is highly variable in space and time, so the equivalent equation will depend a lot on what you chose as present-day H2O concentration.  A ball-park figure for mean H2O concentration is 4000 ppm, which leads to the equation,&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\Delta E = 22 + 0.052[H2O]$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;I should emphasise that this model isn’t intended for any serious calculation.  It’s just a tool to get students used to quantifying parts of the Earth system and how they can trade off against each other.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2021-02-27T11:09:43.107" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20917" PostTypeId="2" ParentId="20902" CreationDate="2021-02-27T11:33:04.020" Score="4" Body="&lt;p&gt;Let's do this with accurate equations. We know how to calculate the saturated water vapour pressure for temperature &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$e_s(T)=e_{s0}e^{\frac{h_i}{R_w}(\frac{1}{T_{s0}}-\frac{1}{T})}=610\text{ Pa} \times e^{5423(\frac{1}{273\text{ K}}-\frac{1}{T})}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$e_s$&lt;/span&gt; is saturated water vapour pressure as function of &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; in Pascals&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; is the temperature in Kelvins&lt;/p&gt;&#xA;&lt;p&gt;So, the saturated water vapour pressure at &lt;span class=&quot;math-container&quot;&gt;$T=0°C=273K$&lt;/span&gt; is equal to &lt;span class=&quot;math-container&quot;&gt;$e_s(273K)=610 Pa$&lt;/span&gt;. Similarly, &lt;span class=&quot;math-container&quot;&gt;$e_s(293K)=2360Pa$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$e_s(283K)=1230Pa$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;So we have two parcels of air: 1. 20°C, 40% and 2. 0°C, 40%. What are the masses of the water vapour in both parcels?&#xA;&lt;span class=&quot;math-container&quot;&gt;$$e=f\times e_s(T)$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$f$&lt;/span&gt; is relative humidity, &lt;span class=&quot;math-container&quot;&gt;$e$&lt;/span&gt; is the water vapour pressure&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$m(T)=\frac{eV}{R_w T}=\frac{f\times e_s(T)\times V}{R_w\times T}=\frac{fe_s(T)V}{461\frac{J}{kg}T}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$m(293K)=0.0070kg$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$m(273K)=0.0019kg$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The next step is to combine these two masses:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$M=m(293K)+m(273K)=0.0089kg$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;So the density is &lt;span class=&quot;math-container&quot;&gt;$\rho=\frac{M}{V}=0.0045\frac{kg}{m^3}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The water vapour pressure is given by:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$e=\rho RT=587Pa$$&lt;/span&gt;&#xA;The relative humidity is then:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$f=\frac{e}{e_s(283K)}=0.477$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;So this is around 48% of the relative humidity.&lt;/p&gt;&#xA;&lt;p&gt;Why did I put here so many equations? Simple! These equations hold on high degree of accuracy, so they can't be wrong. Why would the relative humidity drop in reality?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Also, for Skew-T Log-P lovers:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/xqtpj.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xqtpj.png&quot; alt=&quot;Skew-T Log-P solution&quot; /&gt;&lt;/a&gt;&#xA;This solution is even more concise and less error prone.&lt;/p&gt;&#xA;" OwnerUserId="19122" LastEditorUserId="19122" LastEditDate="2021-04-01T18:56:03.400" LastActivityDate="2021-04-01T18:56:03.400" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20919" PostTypeId="2" ParentId="20915" CreationDate="2021-02-27T18:28:24.823" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;I assume is an annual temperature change relative to the previous year.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;No, that would be called the rate of change. &amp;quot;Anomaly&amp;quot; means the difference from some reference temperature.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2021-02-27T18:28:24.823" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20920" PostTypeId="1" CreationDate="2021-02-28T20:55:35.940" Score="1" ViewCount="53" Body="&lt;p&gt;I am trying to get time series data for a specific place (latitude and longitude) for different weather elements from the CDS datapool. Therefore, I am using the cdsapi package and can run queries such as:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import cdsapi&#xA;import xarray as xr&#xA;&#xA;# settings&#xA;filename = &amp;quot;here.nc&amp;quot;&#xA;&#xA;# request&#xA;c = cdsapi.Client()&#xA;res = c.retrieve(&#xA;    &amp;quot;reanalysis-era5-single-levels&amp;quot;,&#xA;    {&#xA;        &amp;quot;product_type&amp;quot;: &amp;quot;reanalysis&amp;quot;,&#xA;        &amp;quot;variable&amp;quot;: &amp;quot;2m_temperature&amp;quot;,&#xA;        &amp;quot;year&amp;quot;: &amp;quot;2019&amp;quot;,&#xA;        &amp;quot;month&amp;quot;: &amp;quot;01&amp;quot;,&#xA;        &amp;quot;day&amp;quot;: &amp;quot;01&amp;quot;,&#xA;        &amp;quot;time&amp;quot;: [&#xA;            &amp;quot;00:00&amp;quot;,&#xA;        ],&#xA;        &amp;quot;format&amp;quot;: &amp;quot;netcdf&amp;quot;,&#xA;    },&#xA;    filename,&#xA;)&#xA;&#xA;nc = xr.open_dataset(filename, decode_cf=False)&#xA;df = nc.to_dataframe().reset_index(drop=False)&#xA;print(df)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;This can easily be extended to more time points, but not as easily to places (even the returned latitude and longitude coordinates sometimes do are unreasonable).  If I understand correctly the netcdf data is already interpolated, but there is no parameter to specify a distinct place (only area and grid). Because I have to query several places all over the world and want to go a few years back with hourly/daily resolution, querying large grids will not work.&lt;/p&gt;&#xA;&lt;p&gt;Does anybody have an idea how to get the data for a specific place? If possible, I would like to keep my tooling Python only, but happy to use other packages or try other solutions.&lt;/p&gt;&#xA;" OwnerUserId="21942" LastActivityDate="2021-02-28T20:55:35.940" Title="How to specify a certain place in a (CDS) weather data query?" Tags="|meteorology|reanalysis|python|era|netcdf|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20921" PostTypeId="1" CreationDate="2021-03-01T10:16:19.763" Score="2" ViewCount="120" Body="&lt;p&gt;I have an odd map projection requirement, but I would like a world map projection where even very small countries, like Luxembourg or Belgium are still visible when also showing China and Canada on the same map. The idea is to use this map to show reach and engagement with the hue and therefore a map projection that minimises the area differences would be great as it maximises visibility for small countries for a given map size. Obviously angles, area and distances would be distorted, but as long as the country is recognisable (so not like some maps used in electoral mapping) that is fine. I guess rectangular maps would be great and the highest latitudes can be cut. Any ideas?&lt;/p&gt;&#xA;" OwnerUserId="21948" LastActivityDate="2024-01-20T20:39:37.900" Title="map projections that minimises differences" Tags="|mapping|projection|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20922" PostTypeId="2" ParentId="18121" CreationDate="2021-03-01T12:11:28.573" Score="1" Body="&lt;p&gt;Yes, the wind cells are just a toy model, where we can suppose that the homogenity of the Earth and other things. But there &lt;em&gt;are&lt;/em&gt; other things and Earth isn't same on the all points, so the instantaneous winds don't follow their cells. Of course, it is possible (by pure statistics) that sometimes in the Earth history, the majority of the winds was aligned with their cells. But the cells are just averaged over the period of more decades and centuries.&lt;/p&gt;&#xA;" OwnerUserId="19122" LastActivityDate="2021-03-01T12:11:28.573" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20923" PostTypeId="2" ParentId="20921" CreationDate="2021-03-01T21:53:05.603" Score="1" Body="&lt;p&gt;I am sorry, but this type of &lt;em&gt;linear&lt;/em&gt; map can't exist. You said that you want to minimize differences, so you want to make small countries bigger. But unfortunately, big countries become bigger too (because of linear transformation), so that's not the solution.&lt;/p&gt;&#xA;&lt;p&gt;I can only think of scaling individual portions of some standard projection. For example, you could scale Europe a little bit because of many small countries. You could also just scale the islands in the Oceania, but not the distances between them. Oops, it seems like we got too far into cheating, but as long as scaling countries to minimize differences is the only thing you want to do, there is no problem. Of course, your decision is the last.&lt;/p&gt;&#xA;&lt;p&gt;As &lt;a href=&quot;https://earthscience.stackexchange.com/users/6535/keith-mcclary&quot;&gt;@KeithMcClary&lt;/a&gt; pointed out in his comment, this type of map is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Cartogram&quot; rel=&quot;nofollow noreferrer&quot;&gt;cartogram&lt;/a&gt;. Thank you for this useful piece of information!&lt;/p&gt;&#xA;" OwnerUserId="19122" LastEditorUserId="19122" LastEditDate="2021-03-02T19:38:17.017" LastActivityDate="2021-03-02T19:38:17.017" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20924" PostTypeId="1" CreationDate="2021-03-02T02:59:46.520" Score="3" ViewCount="633" Body="&lt;p&gt;I'm confused about how to distinguish the two. Prior to making this question. I've read the &lt;a href=&quot;https://en.wikipedia.org/wiki/Transverse_valley&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia entry on the subject&lt;/a&gt; but it mentions that for example a transverse valley makes 90 degrees with that of the main mountain chain.&lt;/p&gt;&#xA;&lt;p&gt;I'm not savvy with terrain profiles, so this clue about angles makes me confused. So could someone help me with an adequate diagram or picture on how to distinguish it from a longitudinal valley?&lt;/p&gt;&#xA;&lt;p&gt;The same entry mentions about Val de Travers which it warns that despite of its name is a longitudinal valley. But I don't know why does it make this claim.&lt;/p&gt;&#xA;&lt;p&gt;Because none of the articles do properly explain this with some sort of picture other than a photo I can't exactly tell at which difference is being talked about. Thus an arrow or some sort of marker or indicator over the photo or a diagram would be of much help for better identification.&lt;/p&gt;&#xA;" OwnerUserId="21574" LastActivityDate="2021-03-02T09:17:27.343" Title="How to properly distinguish a transversal valley from a longitudinal valley?" Tags="|geography|rivers|mountains|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20925" PostTypeId="2" ParentId="20924" CreationDate="2021-03-02T09:17:27.343" Score="1" Body="&lt;p&gt;I think that the simplest way is to just look at the map for these two valleys in the Switzerland:&lt;/p&gt;&#xA;&lt;p&gt;Longitudinal valley:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/G8w4Bl.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G8w4Bl.jpg&quot; alt=&quot;longitudinal valley&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;You can see that this is perfect example on the map: we can easily see the direction of the ridges and the valley is pointed in the same direction. This type of valley was not made by river, but it was made with compressing of tectonic plates.&lt;/p&gt;&#xA;&lt;p&gt;Transversal valley:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/sJtUhl.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sJtUhl.jpg&quot; alt=&quot;transversal valley&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;You can see here that some river got through the ridge (then they built the road because the river made all work). It doesn't go parallel ridges like the longitudinal valley. This type of valley requires a lot of work for the river so transversal valley are typically pretty short.&lt;/p&gt;&#xA;" OwnerUserId="19122" LastActivityDate="2021-03-02T09:17:27.343" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20926" PostTypeId="1" CreationDate="2021-03-02T15:50:22.313" Score="1" ViewCount="46" Body="&lt;p&gt;I am reading a fantasy novel where there is a mountain range where the average mountain height is 10 miles, so some higher some lower, but all &lt;em&gt;extremely&lt;/em&gt; high.&lt;/p&gt;&#xA;&lt;p&gt;This got me wondering if such a mountain range is possible on earth. Mount Everest is just under 5 1/2 miles, so there is no mountains even close to 10 miles here on earth. But I am wondering if that is because it is impossible for that to occur, or if it just hasn't happened but possibly could.&lt;/p&gt;&#xA;" OwnerUserId="21957" LastActivityDate="2021-03-02T15:50:22.313" Title="Is there a physical limit to the heights of mountains?" Tags="|mountains|" AnswerCount="0" CommentCount="2" ClosedDate="2021-03-02T17:10:18.403" ContentLicense="CC BY-SA 4.0" />
  <row Id="20928" PostTypeId="1" CreationDate="2021-03-03T16:56:07.270" Score="1" ViewCount="24" Body="&lt;p&gt;Where can I find non-country specific, general or most strict set of rules that would pass in most countries, about allowed content of waste water that is allowed to be released into the environment, in most cases?&lt;/p&gt;&#xA;&lt;p&gt;Excluding special cases like ships or particular factories or some countries that are particularly forgiving, or nature reserve rules that are particularly strict.&lt;/p&gt;&#xA;&lt;p&gt;For example, about compounds with C, Fe, Zn, Al, Na, Ca, S, Cl, P, Si, O, H as ions or particles (per particle size), pH&lt;/p&gt;&#xA;&lt;p&gt;Preferably not in a form of 800 pages book that just lists what is prohibited in each specific case.&lt;/p&gt;&#xA;" OwnerUserId="21962" LastEditorUserId="2470" LastEditDate="2021-03-04T00:09:45.900" LastActivityDate="2021-03-04T00:09:45.900" Title="Discharge waste water - content allowed, most strict, universal rule set" Tags="|water|environmental-protection|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20929" PostTypeId="1" CreationDate="2021-03-04T11:00:29.400" Score="2" ViewCount="246" Body="&lt;p&gt;With plate tectonics, supercontinents split up into smaller continents, and then the smaller continents get mashed up together to form a new supercontinent. There used to be a single supercontinent Pangea, and before that there was Rodinia. How many times in the past have all the continents been smashed up together into a single supercontinent?&lt;/p&gt;&#xA;" OwnerUserId="18434" LastActivityDate="2021-03-04T12:21:23.327" Title="How many supercontinents have there been?" Tags="|plate-tectonics|" AnswerCount="1" CommentCount="0" ClosedDate="2021-03-07T05:30:35.913" ContentLicense="CC BY-SA 4.0" />
  <row Id="20930" PostTypeId="2" ParentId="20929" CreationDate="2021-03-04T12:21:23.327" Score="1" Body="&lt;p&gt;There's a fairly decent Wikipedia page about this: &lt;a href=&quot;https://en.wikipedia.org/wiki/Supercontinent&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Supercontinent&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;In short, though, the question of &amp;quot;how many times has this happened?&amp;quot; is very difficult to answer because the further you go back in Earth's history, the less evidence is still left today from that time. Not everything can or will ever be reconstructed with certainty.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2021-03-04T12:21:23.327" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20931" PostTypeId="1" CreationDate="2021-03-04T20:03:41.883" Score="4" ViewCount="122" Body="&lt;p&gt;There is a company called &lt;a href=&quot;https://www.planet.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Planet Labs&lt;/a&gt; which sells daily satellite imagery covering the whole globe that can be used for various research  like agriculture, forestry etc. I wonder if there is a free equivalent of Planet Labs that offers periodically captured satellite or aerial imagery with decent resolution possibly on global scale or at least on regional scale (whole country). Do maybe NASA or ESA offer something periodical with decent coverage and resolution?&lt;/p&gt;&#xA;" OwnerUserId="5762" LastActivityDate="2021-03-06T16:46:39.397" Title="Free periodical satellite/aerial imagery" Tags="|remote-sensing|agriculture|satellites|forest|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20932" PostTypeId="1" CreationDate="2021-03-05T06:15:28.977" Score="4" ViewCount="60" Body="&lt;p&gt;The video in &lt;a href=&quot;https://twitter.com/MichaelMorrah/status/1367608986585862147&quot; rel=&quot;nofollow noreferrer&quot;&gt;this tweet&lt;/a&gt; shows the small wave produced at Tokomaru Bay in New Zealand following the  &lt;a href=&quot;https://earthquake.usgs.gov/earthquakes/eventpage/us7000dflf/executive&quot; rel=&quot;nofollow noreferrer&quot;&gt;M 8.1 - Kermadec Islands, New Zealand 2021-03-04 19:28:31 (UTC)&lt;/a&gt; event. These are so far the only thing I've seen in terms of &amp;quot;data&amp;quot; on waves produced by the quake.&lt;/p&gt;&#xA;&lt;p&gt;Warnings went out and people did rapidly evacuate low elevation coastal areas as a precaution.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Are there any potential measurements of any transient sea-level changes via buoys or perhaps even satellite (e.g. radar, laser), either likely very small ones out at sea or larger ones nearby the coast where the height would be amplified?&lt;/p&gt;&#xA;&lt;p&gt;Or is all information going to be basically anecdotal?&lt;/p&gt;&#xA;&lt;p&gt;The data doesn't necessarily have to be available yet, I'm just curious about what measurement capability exists.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2021-03-05T15:42:35.147" Title="Is there any information on the height of waves near New Zealand resulting from today's M 8.1 Kermadec Islands earthquake?" Tags="|earthquakes|measurements|waves|tsunami|solitary-waves|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20933" PostTypeId="1" CreationDate="2021-03-05T10:10:22.997" Score="2" ViewCount="230" Body="&lt;p&gt;I am having a problem reading in my low version map.&#xA;Besides, any tips on where I can find &amp;quot;free&amp;quot; maps?&lt;/p&gt;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;" OwnerUserId="20981" LastEditorUserId="2470" LastEditDate="2021-03-05T11:19:47.787" LastActivityDate="2021-03-08T10:25:13.737" Title="Does anyone have a geological map 1 / 1 000 000 or 1 / 50k of Morocco in HD?" Tags="|mapping|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20934" PostTypeId="2" ParentId="20932" CreationDate="2021-03-05T15:19:23.347" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Norfolk_Island&quot; rel=&quot;nofollow noreferrer&quot;&gt;Norfolk Island&lt;/a&gt; experienced a &lt;a href=&quot;https://www.smh.com.au/world/oceania/tsunami-warning-after-major-earthquake-strikes-new-zealand-20210305-p577z1.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;tsunami wave 64 cm tall&lt;/a&gt;. In Australia the tsunami wave was 10 cm at &lt;a href=&quot;https://en.wikipedia.org/wiki/Tweed_Heads%2C_New_South_Wales&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tweed Heads&lt;/a&gt; and 9 cm at &lt;a href=&quot;https://en.wikipedia.org/wiki/Port_Kembla%2C_New_South_Wales&quot; rel=&quot;nofollow noreferrer&quot;&gt;Port Kembla&lt;/a&gt;. In Vanuatu the height was 32 cm and in Fiji 13 cm  and 8 cm in Tonga.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.bom.gov.au/tsunami/national.shtml#nationalBulletin0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Australian Burea of Meteorology report&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;TSUNAMI DETAILS:&#xA;The following sea level gauges have observed a tsunami, heights refer to wave&#xA;amplitudes (positive wave values):&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;Name                  Country       Lat     Lon      Height (m)  Time (UTC)&#xA;East Cape             NEW ZEALAND   37.50S  178.17E  0.15        04 MAR 2210&#xA;Nuku'Alofa            TONGA         21.10S  175.20W  0.06        04 MAR 2115&#xA;Suva Viti Levu        FIJI          18.10S  178.42E  0.13        04 MAR 2200&#xA;Rarotonga Wharf       COOK ISLAND   21.20S  159.79W  0.08        04 MAR 2200&#xA;Kaingaroa Chatham Is  PACIFIC OCEA  43.70S  176.27W  0.22        04 MAR 2320&#xA;Norfolk Island.       AUSTRALIA     29.10S  167.95E  0.64        04 MAR 2245&#xA;Port Villa            VANUATU       17.80S  168.31E  0.32        04 MAR 2320&#xA;Ouinne                NEW CALEDONI  22.00S  166.83E  0.2         04 MAR 2320&#xA;Tubuai                FRENCH POLYN  23.30S  149.48W  0.06        04 MAR 2305&#xA;Port Kembla           AUSTRALIA     34.50S  151.00E  0.15        05 MAR 0205&#xA;Mare                  NEW CALEDONI                   0.15        04 MAR 2330&#xA;North Cape            NEW ZEALAND                    0.15        04 MAR 2130&#xA;Great Barrier Island  NEW ZEALAND                    0.20        04 MAR 2240&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;See also &lt;a href=&quot;https://www.abc.net.au/news/2021-03-05/new-zealand-earthquake-tsunami-warning-for-north-island/13218542&quot; rel=&quot;nofollow noreferrer&quot;&gt;[1]&lt;/a&gt;, &lt;a href=&quot;https://www.nzherald.co.nz/nz/earthquake-swarm-north-island-tsunami-warning-lifted-after-81-shake-evacuees-return-home/OOON3VQ4G75ENH7VASABKYUTBM/&quot; rel=&quot;nofollow noreferrer&quot;&gt;[2]&lt;/a&gt; &amp;amp; &lt;a href=&quot;https://www.geonet.org.nz/tsunami&quot; rel=&quot;nofollow noreferrer&quot;&gt;[3]&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-03-05T15:42:35.147" LastActivityDate="2021-03-05T15:42:35.147" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20935" PostTypeId="1" CreationDate="2021-03-05T16:25:27.757" Score="3" ViewCount="204" Body="&lt;p&gt;Different learning resources categorise quartz differently. Strictly speaking, is quartz a silicate mineral or an oxide mineral?&lt;/p&gt;&#xA;" OwnerUserId="21871" LastActivityDate="2021-03-25T08:36:04.630" Title="Quartz mineral category" Tags="|geology|mineralogy|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20936" PostTypeId="2" ParentId="20935" CreationDate="2021-03-05T18:49:03.693" Score="4" Body="&lt;p&gt;Quartz is a silicate at the most used Dana and Strunz classifications of minerals.&lt;/p&gt;&#xA;&lt;p&gt;Several &lt;a href=&quot;http://webmineral.com/data/Quartz.shtml#.YEJ8Y-CCEzQ&quot; rel=&quot;nofollow noreferrer&quot;&gt;websites&lt;/a&gt; and mineralogists classify it as silicate.&lt;/p&gt;&#xA;&lt;p&gt;The structure of quartz is similar to other silicates with Si-O tetrahedres.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/pJkUc.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;Quartz structure. &lt;a href=&quot;http://www.quartzpage.de/gen_struct.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;quartzpage.de&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-03-25T08:36:04.630" LastActivityDate="2021-03-25T08:36:04.630" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20937" PostTypeId="1" CreationDate="2021-03-05T20:01:11.193" Score="7" ViewCount="2488" Body="&lt;p&gt;From &lt;a href=&quot;https://www.nature.com/scitable/knowledge/library/the-global-climate-system-74649049/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nature&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;We divide by &lt;span class=&quot;math-container&quot;&gt;$4$&lt;/span&gt; since the solar energy is spread over the surface of the planetary sphere. The Earth intercepts a circular area of incoming sunlight, and this area is spread over a sphere with the same radius as the circle (area of circle / area of sphere of same radius = &lt;span class=&quot;math-container&quot;&gt;$0.25$&lt;/span&gt;).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;It would seem by dividing by 4 it results in the sun's energy being evenly distributed over the entire globe at the same time as if the earth was flat, and weakening the actual energy required to create a climate. I don't see any logical reason to do this as we know this doesn't physically happen.&lt;/p&gt;&#xA;&lt;p&gt;What is the explanation? Why do you need to average out the sun's energy over the whole planet at the same time when that's not what actually happens?&lt;/p&gt;&#xA;" OwnerUserId="21853" LastEditorUserId="6129" LastEditDate="2021-03-06T13:38:36.897" LastActivityDate="2021-03-06T17:48:24.627" Title="Why divide total insolation by $4$?" Tags="|climate-change|climate|insolation|" AnswerCount="3" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="20938" PostTypeId="2" ParentId="20937" CreationDate="2021-03-05T21:34:06.457" Score="8" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Why does climate science divide total insolation by 4?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;For two reasons, each of which halves the effects of insolation:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;At any point in time, only half of the Earth is illuminated by the Sun. Another name for this factor is &amp;quot;daytime&amp;quot; versus &amp;quot;nighttime&amp;quot;.&lt;/li&gt;&#xA;&lt;li&gt;At any point in time, the surface area of the Earth's hemisphere that is illuminated by the Sun is about &lt;span class=&quot;math-container&quot;&gt;$2\pi r^2$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; is the radius of the Earth. But the cross section of that hemisphere to solar radiation is the area of a circle of radius &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt;, which is &lt;span class=&quot;math-container&quot;&gt;$\pi r^2$&lt;/span&gt;, half of the area of that hemisphere.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;? Why do you need to average out the sun's energy over the whole planet at the same time when that's not what actually happens?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The Earth rotates fairly quickly, so that &lt;strong&gt;is&lt;/strong&gt; what happens. If the Earth was tidally locked with the Sun, there would be one side of the Earth that would be very hot and one side of the Earth that would be very cold. That is not what happens.&lt;/p&gt;&#xA;&lt;p&gt;If the Earth rotated once per month (which is what our Moon does do), the sunlit side would eventually come close to being in thermal equilibrium with the incoming sunlight while the dark side would cool to much colder temperatures than are experienced anywhere on the face of the Earth. That also is not what happens. Even the sunlit Sahara does not get as hot as do equatorial regions of the Moon, and even South Pole does not get as cold as do portions of the Moon.&lt;/p&gt;&#xA;&lt;p&gt;The periods of daytime heating by sunlight and periods of nighttime cooling by the lack of sunlight are both far too brief to bring those portions of the Earth into thermal equilibrium with the sunlight at daytime or with the 2.7K cosmic microwave background radiation at nighttime.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2021-03-05T21:56:18.217" LastActivityDate="2021-03-05T21:56:18.217" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20939" PostTypeId="2" ParentId="20937" CreationDate="2021-03-05T21:44:06.360" Score="1" Body="&lt;p&gt;Climate science studies the processes on the Earth over the course of many centuries. The rotation of the Earth is so small compared to many centuries.&lt;/p&gt;&#xA;&lt;p&gt;Imagine that we roast the chicken. We can approximate &lt;a href=&quot;https://en.wikipedia.org/wiki/Spherical_cow&quot; rel=&quot;nofollow noreferrer&quot;&gt;the chicken as a sphere&lt;/a&gt;. The sphere (or chicken) is continuously revolving, thus the source of heat is changing the hemisphere that is being roasted. At the instant of time, only one hemisphere is being roasted. But imagine that the chicken spins at 1000 revolutions per second. (Of course, roasting chicken on a drill is not recommended.) You see, that the effects cancel out, and the total heat is equal to half of the instantenous heat.&lt;/p&gt;&#xA;&lt;p&gt;Now the calculations: How much is the instantenous heat?&#xA;&lt;span class=&quot;math-container&quot;&gt;$$(1-a)\Omega\pi r^2$$&lt;/span&gt;&#xA;But this heat is divided evenly to the whole hemisphere, so:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{(1-a)\Omega\pi r^2}{2\pi r^2}=\frac{(1-a)\Omega}{2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;But we said the the average heat is just a half of that, so we get wanted:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{(1-a)\Omega}{4}$$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="19122" LastActivityDate="2021-03-05T21:44:06.360" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20940" PostTypeId="2" ParentId="20933" CreationDate="2021-03-05T21:46:52.310" Score="3" Body="&lt;p&gt;It is not so evident if you look for the big picture (grammar school's project?), or detail and specific region.  Because even today, the geological mapping of Morocco is not complete (&lt;a href=&quot;https://www.mem.gov.ma/en/Pages/secteur.aspx?e=8&quot; rel=&quot;nofollow noreferrer&quot;&gt;gouvernmental reference&lt;/a&gt;), the 19 already digitized geological maps about Morocco  on &lt;a href=&quot;https://gallica.bnf.fr/services/engine/search/sru?operation=searchRetrieve&amp;amp;version=1.2&amp;amp;startRecord=0&amp;amp;maximumRecords=15&amp;amp;page=1&amp;amp;query=(gallica%20all%20%22maroc%20geologie%22)&amp;amp;filter=dc.type%20all%20%22carte%22&quot; rel=&quot;nofollow noreferrer&quot;&gt;gallica.fr&lt;/a&gt; may be an interesting entry for you.  The GUI interface is more helpful for books, than for maps (selection of the page, export as .pdf / .jpeg), but there is a zoom and pan option to see some details on the maps pretty well.&lt;/p&gt;&#xA;&lt;p&gt;E.g., a more general one by Brumnich (1936, 1:500'000) &lt;a href=&quot;https://gallica.bnf.fr/ark:/12148/btv1b53121384p/f1.item.r=maroc%20geologie%20carte.zoom&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, or one with stratigraphic / petrographic details about central Morocco by Termier (1932, 1:200'000) &lt;a href=&quot;https://gallica.bnf.fr/ark:/12148/btv1b530668257/f1.item.r=maroc%20geologie.zoom&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="18990" LastEditorUserId="2470" LastEditDate="2021-03-06T13:42:08.950" LastActivityDate="2021-03-06T13:42:08.950" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20943" PostTypeId="2" ParentId="20931" CreationDate="2021-03-06T16:46:39.397" Score="4" Body="&lt;p&gt;There are a wide ranging of publically available satellite images with different spatial and temporal resolutions. Notably Landsat (&lt;code&gt;https://earthexplorer.usgs.gov/&lt;/code&gt;) and Sentinel (&lt;code&gt;https://scihub.copernicus.eu/dhus/#/home&lt;/code&gt;) come to mind.&#xA;If you are interested in analysing remote sensing products at a global or regional scale, Google Earth Engine (&lt;code&gt;https://developers.google.com/earth-engine&lt;/code&gt;) may be a useful tool for you. GEE can directly access Landsat and Sentinel products at no cost to the user.&lt;/p&gt;&#xA;&lt;p&gt;I hope this information is of use to you.&lt;/p&gt;&#xA;" OwnerDisplayName="user21973" LastActivityDate="2021-03-06T16:46:39.397" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20944" PostTypeId="2" ParentId="20937" CreationDate="2021-03-06T17:30:03.520" Score="4" Body="&lt;p&gt;My answer is mainly here to give some quantitative reasoning, but for the sake of completeness I'll also answer what my predecessors already answered.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Why do we divide by 4?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Imagine you see earth from the perspective of the sun. What you see is a disc. The area of this disc is &lt;span class=&quot;math-container&quot;&gt;$\pi r^2$&lt;/span&gt; and therefore the total energy earth received from the sun is &lt;span class=&quot;math-container&quot;&gt;$S_0 \pi r^2 (1-\alpha)$&lt;/span&gt;, where the &lt;span class=&quot;math-container&quot;&gt;$(1-\alpha)$&lt;/span&gt; takes into account that the solar radiation is &lt;a href=&quot;https://en.wikipedia.org/wiki/Albedo&quot; rel=&quot;nofollow noreferrer&quot;&gt;partly reflected&lt;/a&gt;. As stated in the other answers,  the idea is to distribute the energy over the whole surface of earth &lt;span class=&quot;math-container&quot;&gt;$4\pi r^2$&lt;/span&gt;. Thus, energy received per &lt;span class=&quot;math-container&quot;&gt;$m^2$&lt;/span&gt; is &lt;span class=&quot;math-container&quot;&gt;$\frac{S_0 (1-\alpha)}{4}$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Why is it reasonable to assume that the energy is distributed evenly over the whole globe at an instant?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;The short answer is:&#xA;If we use this assumption we are usually dealing with timescales much longer than a full rotation of the earth. Thus, daily variations are negligible.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;A quantitative example&lt;/strong&gt;:&lt;/p&gt;&#xA;&lt;p&gt;Let's compare the time it takes the atmosphere to adjust to an imbalance &lt;span class=&quot;math-container&quot;&gt;$N$&lt;/span&gt; to the time it takes the earth to rotate once. A full rotation takes approximately &lt;span class=&quot;math-container&quot;&gt;$t_{rot} \approx 60\times60\times24s = 86400s$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The imbalance problem requires a few explanations up front. Suppose we double &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; in the atmosphere. This causes a &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiative_forcing&quot; rel=&quot;nofollow noreferrer&quot;&gt;forcing&lt;/a&gt; of &lt;span class=&quot;math-container&quot;&gt;$F_{2 \times CO_2} \approx 3.7 \frac{W}{m^2}$&lt;/span&gt; according to &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/03/TAR-06.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC&lt;/a&gt;. We now want to know how long it takes the atmosphere to adjust to this forcing.&lt;/p&gt;&#xA;&lt;p&gt;Let's setup a model: Following &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2003GL018747&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gregory et. al.&lt;/a&gt; we model the imbalance linearly as&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$N = F_{2 \times CO_2} + \lambda T$&lt;/span&gt;,&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; is the temperature relative to some reference &lt;span class=&quot;math-container&quot;&gt;$T_0$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt; is the (negative) &lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_change_feedback&quot; rel=&quot;nofollow noreferrer&quot;&gt;feedback parameter&lt;/a&gt; with units &lt;span class=&quot;math-container&quot;&gt;$\frac{W}{m^2 K}$&lt;/span&gt;. Thus an increase in temperature reduces the imbalance. Additionally we assume that the imbalance will lead to an increase in temperature over time (as done e.g. &lt;a href=&quot;https://link.springer.com/article/10.1007/s00382-019-04686-4&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$N = C\frac{\text{d}T}{\text{d}t}$&lt;/span&gt;,&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt; is time and &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; is the heat capacity of the atmosphere. Combining the two equations above we find&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$C\frac{\text{d}T}{\text{d}t} = F_{2 \times CO_2} + \lambda T$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The solution to the differential equation above is&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$T(t) = \frac{-F_{2\times CO_2}}{\lambda} \left(1 - e^{\frac{\lambda}{C}t} \right)$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;We can see the adjustment process takes an infinite time, however two thirds of the process are done within the &lt;span class=&quot;math-container&quot;&gt;$e$&lt;/span&gt;-folding time &lt;span class=&quot;math-container&quot;&gt;$\tau$&lt;/span&gt; (when the term in the exponent is &lt;span class=&quot;math-container&quot;&gt;$-1$&lt;/span&gt;). The exponent is &lt;span class=&quot;math-container&quot;&gt;$-1$&lt;/span&gt; if &lt;span class=&quot;math-container&quot;&gt;$t = \tau = \frac{-C}{\lambda}$&lt;/span&gt;.&#xA;Note that if &lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt; is approaching infinity we have &lt;span class=&quot;math-container&quot;&gt;$T(\infty) = \frac{-F_{2\times CO_2}}{\lambda}$&lt;/span&gt; (This is called Equilibrium climate sensitivity in the case of doubling &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt;).&lt;/p&gt;&#xA;&lt;p&gt;What's left to do is estimating &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt;. We can estimate the heat capacity of the atmosphere (just a column) to be&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$C = c_p \frac{p_s}{g} = \frac{1005 \frac{J}{K kg} 10^5 Pa }{9.81 \frac{m}{s^2}} = 1.02 \times 10^7 \frac{J}{m^2 K}$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_TS_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC tells us&lt;/a&gt; that &lt;span class=&quot;math-container&quot;&gt;$T(\infty)$&lt;/span&gt; is likely to be between &lt;span class=&quot;math-container&quot;&gt;$1.5°C - 4.5°C$&lt;/span&gt;. Let's set &lt;span class=&quot;math-container&quot;&gt;$T(\infty) = 3°C$&lt;/span&gt; and calculate&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\lambda = -\frac{3.7 \frac{W}{m^2}}{3 K} = -1.23 \frac{W}{m^2 K}$&lt;/span&gt;. Finally we find&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\tau = - \frac{1.02 \times 10^7 \frac{J}{m^2 K}}{-1.23 \frac{W}{m^2 K}} \approx 8.7 \times 10^6 s \approx 100\times t_{rot} $&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Caution&lt;/strong&gt;&#xA;In reality the time scales differ a lot more. The oceans heat capacity is much higher than the atmospheres. However, the calculations above should convince you that even if all forcing changes atmosphere only time scales differ by at least &lt;span class=&quot;math-container&quot;&gt;$\mathcal{O}(2)$&lt;/span&gt;.&lt;/p&gt;&#xA;" OwnerUserId="18833" LastEditorUserId="18833" LastEditDate="2021-03-06T17:48:24.627" LastActivityDate="2021-03-06T17:48:24.627" CommentCount="16" ContentLicense="CC BY-SA 4.0" />
  <row Id="20945" PostTypeId="2" ParentId="7537" CreationDate="2021-03-07T15:52:26.283" Score="2" Body="&lt;p&gt;These are not pure satellite images.&lt;/p&gt;&#xA;&lt;p&gt;On the images shown in the question, one can see bathymetry in the oceans that cannot be seen from a satellite image.  Rather, those images use a static image background (the land may be from a satellite mosaic, but not the ocean) along with a calculated cloud mask, then show the satellite image only where there are clouds (probably an infrared image where cold clouds are white).  The differences between the two satellite images therefore have less to do with instrument differences than with differences in post-processing.&lt;/p&gt;&#xA;&lt;p&gt;From &lt;a href=&quot;https://worldview.earthdata.nasa.gov/?v=-29.883444587778115,-40.68694904216132,209.57694531542052,73.68033092723095&amp;amp;l=VIIRS_CrIS_SNPP_BT_Band33_Fusion_Day,VIIRS_CrIS_SNPP_BT_Band33_Fusion_Night(hidden),Reference_Labels(hidden),Reference_Features(hidden),Coastlines,VIIRS_NOAA20_CorrectedReflectance_TrueColor,VIIRS_SNPP_CorrectedReflectance_TrueColor(hidden),MODIS_Aqua_CorrectedReflectance_TrueColor(hidden),MODIS_Terra_CorrectedReflectance_TrueColor(hidden)&amp;amp;lg=true&amp;amp;t=2016-02-20-T15%3A47%3A38Z&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA WorldView&lt;/a&gt; we can see what an actual infrared satellite image at this time looks like (again with cold clouds white, hot surfaces black), in this case from VIIRS on the polar orbiter Suomi NPP at a wavelength of 13.3 µm (I didn't immediately have IODC/Seviri images at hand, I may check mack later for those):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/f4ubM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/f4ubM.jpg&quot; alt=&quot;VIIRS&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;em&gt;Source: NASA Worldview, imagery from VIIRS&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2021-03-08T09:33:50.963" LastActivityDate="2021-03-08T09:33:50.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20948" PostTypeId="1" CreationDate="2021-03-08T16:39:14.490" Score="5" ViewCount="427" Body="&lt;p&gt;New oceanic crust is formed at mid-ocean ridges, then destroyed during subduction. Continental crust can be destroyed with erosion, or when the crust gets too thick (under mountains) and starts to melt at the base, but how does it form? Or is the continental crust slowly disappearing?&lt;/p&gt;&#xA;" OwnerUserId="18434" LastActivityDate="2021-03-25T12:48:06.770" Title="How does new continental crust form?" Tags="|continental-crust|" AnswerCount="1" CommentCount="5" ClosedDate="2021-03-29T05:01:39.050" ContentLicense="CC BY-SA 4.0" />
  <row Id="20949" PostTypeId="1" CreationDate="2021-03-08T16:40:57.983" Score="4" ViewCount="121" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/s2Jkd.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/s2Jkd.jpg&quot; alt=&quot;rock classification&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;From the chart, I would say that plagioclase feldspar is more abundant in coarse-grained igneous rocks than alkali feldspar, as it is found in all three listed, whereas alkali feldspar is only present in diorite and granite.&lt;/p&gt;&#xA;&lt;p&gt;Apparently I am wrong, can anyone please explain to me why?&lt;/p&gt;&#xA;" OwnerUserId="21871" LastActivityDate="2021-03-14T09:04:40.593" Title="Feldspar content of coarse-grained igneous rocks" Tags="|geology|mineralogy|rocks|igneous|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20950" PostTypeId="2" ParentId="20949" CreationDate="2021-03-08T22:13:42.333" Score="2" Body="&lt;p&gt;You can't really generalize like that for all igneous rock ranges.  The chart actually tells you what the type and (approximate) mineral composition of a rock are as functions of the chemical composition, specifically silica content.  You should be looking at how the minerals are distributed as a function of silica content.&lt;/p&gt;&#xA;&lt;p&gt;To understand this diagram fully, note the following:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The horizontal axis is actually a continuous variable, typically the silica content you would obtain if you were to separate all the individual oxide components.  This diagram seems to go roughly from 50% to 70% from left to right; the one quoted &lt;a href=&quot;https://space.stackexchange.com/a/50611/28871&quot;&gt;here&lt;/a&gt; which includes rocks found predominantly in the mantle goes down to 40%.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The rocks are classified according to silica content and crystal or grain size; thus granite and rhyolite are similar in silica content and are regarded in the diagram as having similar mineral compositions; only the grain size is really different.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Thus the curved lines define how much of each mineral is typically in a rock having some level of silica content, which varies across the chart as indicated in point (1).  When we have a high silica content more than about 65% (felsic rocks) in a granite or rhyolite, there can be more alkali feldspar than plagioclase feldspar (the alkali feldspar composition range is higher in silica).  In contrast, a low-silica (mafic) rock won't have any alkali feldspar and even the more flexible plagioclase feldspar is limited; mafic rocks are higher in other minerals such as pyroxenes.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2021-03-09T10:14:28.290" LastActivityDate="2021-03-09T10:14:28.290" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20951" PostTypeId="2" ParentId="10625" CreationDate="2021-03-09T02:07:40.290" Score="3" Body="&lt;p&gt;I have gone over these in a fishing boat many times. I often use this as a fish locator with some shoaling fish around the Uk. One side to the other does show a difference in water temps on the temp sensors fitted to the hull.  It is my belief that these lanes are caused by differing temperature of water columns and an upwelling on the surface, between the 2 differing density of water. One being warmer than the other causes a density + temp fluctuation and the upwelling on collision. This upwelling caused the flat spots or lanes that can go for miles on times or maybe just a few hundred feet depending on the area at sea. Fish do tend to sit on one side or the other of these marks on the surface that appear dead flat and like river streams, flat on the sea surface apposed to the ripped water - They can be as wide as 20ft or more but often are no more than 10ft or less but are quite long and often going in one direction and then another.  So i would say this is more to do with Currents - tidal movements of water and differing water temp columns.&#xA;I would like to add - That salinity could also be part to play as many river pour into bay areas and i have overserved the flats spots during different stages of a tidal hight. Usually around top water when the water flows slow down some.&lt;/p&gt;&#xA;" OwnerUserId="21980" LastEditorUserId="21980" LastEditDate="2021-03-09T02:15:17.340" LastActivityDate="2021-03-09T02:15:17.340" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20952" PostTypeId="1" CreationDate="2021-03-09T19:26:10.863" Score="2" ViewCount="56" Body="&lt;p&gt;I am currently reading &amp;quot;Introduction to seismology second edition, and I can't wrap my head around earthquake sources, especially equivalent body force.&lt;/p&gt;&#xA;&lt;p&gt;What is an “equivalent body force” and how is it justified? Are there any examples of force&#xA;systems that are frequently used to interpret seismograms and their real-world&#xA;equivalents. How the force systems are defined, how they operate and how they are mathematically represented??&lt;/p&gt;&#xA;" OwnerUserId="21934" LastActivityDate="2021-03-09T19:26:10.863" Title="equivalent body force" Tags="|seismology|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20953" PostTypeId="1" CreationDate="2021-03-10T16:17:36.243" Score="4" ViewCount="94" Body="&lt;p&gt;I understand that since the rise of the Soviet Union the Aral sea has dried up more and more due to irrigation from rivers diverting its water to other areas for the sake of agriculture.&lt;/p&gt;&#xA;&lt;p&gt;But is it possible that a drying process started long before the Soviet Union?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/15720/before-the-artificial-changes-of-the-aral-sea-what-was-its-average-depth-and-sa&quot;&gt;This question&lt;/a&gt; gives some input on believed depth and salinity in the past.&#xA;But what, allegedly, was the size of Aral sea in like the year 1000 CE (or even before that), and what information leads to that conclusion?&lt;/p&gt;&#xA;" OwnerUserId="21991" LastEditorUserId="6298" LastEditDate="2021-03-11T04:21:34.443" LastActivityDate="2021-03-18T16:00:18.967" Title="What was the size of the Aral sea in year 1000 CE?" Tags="|geography|water|human-influence|lakes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20955" PostTypeId="2" ParentId="20186" CreationDate="2021-03-11T16:39:36.680" Score="2" Body="&lt;p&gt;To complement the other answers: it is also true that the coastline in that region hasn't been fully documented yet, primarily because a large amount of it is covered by glaciers.&lt;/p&gt;&#xA;&lt;p&gt;As an example, Sif Island (arguably of moderate size but still) was only &lt;a href=&quot;https://www.livescience.com/uncharted-island-discovered-antarctica.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;discovered last year&lt;/a&gt; in the Amundsen Sea embayment (at the left end of your second map) by the THOR expedition when the glacier melted enough for them to see it.&lt;/p&gt;&#xA;" OwnerUserId="87" LastEditorUserId="87" LastEditDate="2021-03-12T07:22:34.673" LastActivityDate="2021-03-12T07:22:34.673" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20956" PostTypeId="1" AcceptedAnswerId="22410" CreationDate="2021-03-11T16:39:52.897" Score="9" ViewCount="3771" Body="&lt;p&gt;Most deserts are a result of the rainshadow effect, cold currents, the subtropical ridges, or a combination of those. Knowing this, how is the Somali desert caused?&lt;/p&gt;&#xA;&lt;p&gt;It is notable since it has a desert climate close to the equator, which is known for being wet. Furthermore, it is on the East Coast of Africa, and Eastern Coasts within 0 to 45 degrees latitude are almost always wet.&lt;/p&gt;&#xA;&lt;p&gt;I've searched and read about the rainshadow effect of the Ethiopian highlands causing the rainshadow effect. However, the trade winds go towards the East, which should make Somalia even wetter. I've read about the monsoon effect, which would explain the rainshadow effect... for the summer. In the winter, however, the wind should bring moist air back to Somalia. So if anything, Somalia should be a tropical Mediterranean climate. Reports say that entire years can go by without rain though.&lt;/p&gt;&#xA;&lt;p&gt;In summary, my question asks for the cause(s) of the Somali desert being so dry and why it isn't a Mediterranean climate.&lt;/p&gt;&#xA;" OwnerUserId="21997" LastEditorDisplayName="user1066" LastEditDate="2021-06-18T15:33:30.720" LastActivityDate="2021-10-11T10:41:46.117" Title="Why is Somalia so dry?" Tags="|climate|ocean-currents|monsoon|coastal-desert|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20958" PostTypeId="1" AcceptedAnswerId="20967" CreationDate="2021-03-12T15:33:10.137" Score="3" ViewCount="1456" Body="&lt;p&gt;I have been given the following data:&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th&gt;Month&lt;/th&gt;&#xA;&lt;th&gt;N&lt;/th&gt;&#xA;&lt;th&gt;T (degrees C)&lt;/th&gt;&#xA;&lt;th&gt;Monthly Rainfall (mm)&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;1&lt;/td&gt;&#xA;&lt;td&gt;0.68&lt;/td&gt;&#xA;&lt;td&gt;1.12&lt;/td&gt;&#xA;&lt;td&gt;391.1&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;2&lt;/td&gt;&#xA;&lt;td&gt;0.82&lt;/td&gt;&#xA;&lt;td&gt;1.40&lt;/td&gt;&#xA;&lt;td&gt;163.1&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;3&lt;/td&gt;&#xA;&lt;td&gt;0.98&lt;/td&gt;&#xA;&lt;td&gt;3.04&lt;/td&gt;&#xA;&lt;td&gt;296.5&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;4&lt;/td&gt;&#xA;&lt;td&gt;1.15&lt;/td&gt;&#xA;&lt;td&gt;4.77&lt;/td&gt;&#xA;&lt;td&gt;157.7&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;&#xA;&lt;p&gt;The list goes on.&#xA;From this and using the Thornthwaite Equation, I calculated both I and Ep&#xA;(Where Ep = monthly potential evaporation (mm), N = relative day length, T = average monthly temperature in celcius, I = monthly heat index)&#xA;(3 d.p.)&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th&gt;Month&lt;/th&gt;&#xA;&lt;th&gt;I&lt;/th&gt;&#xA;&lt;th&gt;Ep&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;1&lt;/td&gt;&#xA;&lt;td&gt;0.106&lt;/td&gt;&#xA;&lt;td&gt;114.941&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;2&lt;/td&gt;&#xA;&lt;td&gt;0.148&lt;/td&gt;&#xA;&lt;td&gt;123.972&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;3&lt;/td&gt;&#xA;&lt;td&gt;0.474&lt;/td&gt;&#xA;&lt;td&gt;100.546&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;4&lt;/td&gt;&#xA;&lt;td&gt;0.932&lt;/td&gt;&#xA;&lt;td&gt;94.192&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;&#xA;&lt;p&gt;The list goes on.&lt;/p&gt;&#xA;&lt;p&gt;From this I need to calculate riverflow/streamflow given as monthly rain - Ep.&#xA;Thus:&#xA;(3 d.p.)&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th&gt;Month&lt;/th&gt;&#xA;&lt;th&gt;Riverflow&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;1&lt;/td&gt;&#xA;&lt;td&gt;276.159&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;2&lt;/td&gt;&#xA;&lt;td&gt;39.128&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;3&lt;/td&gt;&#xA;&lt;td&gt;195.954&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;4&lt;/td&gt;&#xA;&lt;td&gt;63.508&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;&#xA;&lt;p&gt;The list goes on.&lt;/p&gt;&#xA;&lt;p&gt;However, I have been asked for 2 reasons why the flow I have predicted would be inaccurate. In other words, to more accurately predict riverflow what extra data would I need?&lt;/p&gt;&#xA;" OwnerUserId="22000" LastActivityDate="2021-03-18T21:17:17.277" Title="Calculating Stream Flow from Rainfall Data" Tags="|hydrology|rivers|rainfall|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20960" PostTypeId="2" ParentId="20949" CreationDate="2021-03-14T09:04:40.593" Score="2" Body="&lt;p&gt;Let me just add to the other answer:&lt;/p&gt;&#xA;&lt;p&gt;Plagioclase feldspar is the most common mineral in the Earth's crust. You will find it in most rocks plutonic rocks, and it is also a very common mineral in volcanic rocks. You will find it in gabbros, diorites, andesites, most basalts, most granites, some  rhyolites, all monzonites, some peridotites, and list goes on and on.&lt;/p&gt;&#xA;&lt;p&gt;Alkali-feldspar isn't as common. The only common rocks which contain alkali-feldspar are most granites and their volcanic chemical equivalent, rhyolites. Other than that, you will find alkali-feldspar only is more rare rocks such as syenites and other weird rocks that  you will probably never see or hear about.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-03-14T09:04:40.593" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20961" PostTypeId="2" ParentId="20935" CreationDate="2021-03-14T09:06:50.933" Score="3" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;quartz a silicate mineral or an oxide mineral&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Both. The two are not mutually exclusive.&lt;/p&gt;&#xA;&lt;p&gt;Quartz is an oxide, because it is an oxide of the element silicon.&lt;/p&gt;&#xA;&lt;p&gt;Quartz is also a silicate, because it is composed of a framework of silicate tetrahedra.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-03-14T09:06:50.933" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20962" PostTypeId="1" CreationDate="2021-03-14T12:04:23.017" Score="4" ViewCount="149" Body="&lt;p&gt;Italy’s relatively straight, parallel coastlines in the main part of the “boot” seem surprising given how the Apennines snake through it, from one side to the other and back. Don’t coastlines usually parallel mountain ranges more closely? Is there a good account of the geological forces shaping Italy’s coastlines?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/E5yqV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/E5yqV.jpg&quot; alt=&quot;relief map of Italy&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4611" LastActivityDate="2021-03-25T12:40:18.497" Title="Why the difference between Italian coastlines and mountain ranges?" Tags="|mountains|orogeny|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20963" PostTypeId="1" CreationDate="2021-03-14T22:18:33.720" Score="2" ViewCount="32" Body="&lt;p&gt;I need to understand more about thematic 4D mapping. I would roughly classify it as a method of cartography. In particular I want to do research on what software is being used to create thematic 4D maps or other 4D maps (like 4D maps in city planning). Also I want to find out what some general aspects of thematic 4D maps are.&lt;/p&gt;&#xA;&lt;p&gt;Since this is kind of a special field, I'll probably have to look in more specialized literature database, other then Google Scholar and the like. The number of results I get on the broader literature databases are very limited.&lt;/p&gt;&#xA;&lt;p&gt;What literature databases come to your mind where I might find anything about this topic?&lt;/p&gt;&#xA;&lt;p&gt;To get an idea what thematic 4D mapping is all about, here is probably the most recognized paper on the subject: &lt;a href=&quot;https://www.tandfonline.com/doi/full/10.1179/1743277413Y.0000000062&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.tandfonline.com/doi/full/10.1179/1743277413Y.0000000062&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14690" LastActivityDate="2021-03-14T22:18:33.720" Title="Literature on thematic 4D maps" Tags="|mapping|gis|cartography|literature-request|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20964" PostTypeId="1" CreationDate="2021-03-15T03:49:15.857" Score="3" ViewCount="164" Body="&lt;p&gt;Visiting Google Maps, I came across this long, sinuous, while pretty regular mark undersea that looks like an ancient river, when the sea was way lower, or a big (big!) boulder that could have rolled down to the bottom (?).&lt;/p&gt;&#xA;&lt;p&gt;Given the location (ring of fire), it could also be a &amp;quot;crack&amp;quot; made during a major (and ancient) earthquake that, with time, has been filled with sediments.&lt;/p&gt;&#xA;&lt;p&gt;This looks like &lt;a href=&quot;https://earthscience.stackexchange.com/questions/5189/undersea-riverbeds&quot;&gt;this question&lt;/a&gt;, but the shape is very different, and much less sinuous than the one in Japan.&lt;/p&gt;&#xA;&lt;p&gt;The mark:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/c7eFp.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/c7eFp.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The location:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pscvf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pscvf.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22030" LastEditorUserId="6298" LastEditDate="2023-10-12T10:24:06.007" LastActivityDate="2023-10-12T10:24:06.007" Title="What is this long mark undersea" Tags="|geology|earthquakes|satellite-oddities|sea-floor|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20965" PostTypeId="1" CreationDate="2021-03-15T17:07:55.240" Score="6" ViewCount="68" Body="&lt;p&gt;Consider air pollutants like carbon monoxide and nitrogen dioxide for which we use their chemical formulas, &lt;span class=&quot;math-container&quot;&gt;$\ce{CO}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\ce{NO2}$&lt;/span&gt; respectively, as a way to compactly refer to them when writing reports or academic papers. However there are some pollutants for which this notation does not correspond to a chemical formula, &lt;em&gt;e.g.&lt;/em&gt; particulate matter which we also represent like this: &lt;span class=&quot;math-container&quot;&gt;$\ce{PM10}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\ce{PM_{2.5}}$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Considering this, it feels that calling this notation a &amp;quot;chemical formula&amp;quot; is not appropriate. So what is the right name for this notation?&lt;/p&gt;&#xA;" OwnerUserId="22032" LastEditorUserId="22032" LastEditDate="2023-01-31T00:57:53.310" LastActivityDate="2023-01-31T00:57:53.310" Title="What is the appropriate name for air pollutant chemical formula like notation?" Tags="|air-pollution|air-quality|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="20966" PostTypeId="2" ParentId="4505" CreationDate="2021-03-15T20:11:03.753" Score="0" Body="&lt;p&gt;If you speak on calendar seasons base then spring is definitely colder than autumn. March is similar to December (slightly warmer) when September is similar to June (slightly cooler). If you go on astronomical seasons base then things will be different. March is similar to the period of year November 20 - December 20.&lt;/p&gt;&#xA;" OwnerUserId="22036" LastActivityDate="2021-03-15T20:11:03.753" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20967" PostTypeId="2" ParentId="20958" CreationDate="2021-03-15T21:49:53.640" Score="2" Body="&lt;p&gt;Calculating river flow from rainfall - evaporation is a simplification. Firstly you are assuming that you can accurately measure rainfall, then that theoretical estimates of evaporation are correct which, given how much land cover and vegetation vary, is unlikely.&lt;/p&gt;&#xA;&lt;p&gt;Next consider the pathway from raindrop hitting the soil to the river. It's clearly not instantaneous. That raindrop can evaporate directly, run off over the ground surface or soak into soil. In the soil it can be taken up by vegetation or infiltrate and become groundwater recharge. Depending on soil and aquifer characteristics this introduces a delay in the conversion of rainfall to runoff. In the real world this delay could be weeks, months or even years. In your example it's also worth thinking about low temperatures. Is rain falling as rain or is it snow?&lt;/p&gt;&#xA;&lt;p&gt;Thirdly consider how water can get diverted from its pathway to a river. Is water abstracted from the pathway (i.e. from an aquifer),  or from the river directly?  Conversely reservoirs may regulate flows, either up or down depending on management.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastEditorUserId="21672" LastEditDate="2021-03-16T09:21:37.643" LastActivityDate="2021-03-16T09:21:37.643" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20969" PostTypeId="1" AcceptedAnswerId="20997" CreationDate="2021-03-16T14:04:53.543" Score="2" ViewCount="63" Body="&lt;p&gt;What type of ore deposit does this rock best represent?&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A rock with a porphyritic texture is cross cut by a stockwork of&#xA;quartz veins.  Bordering the veins is extensive alteration of the host&#xA;rock. The vein contains fine-grained (~1mm) chalcopyrite and&#xA;molybdenite.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I believe it to be a hydrothermal ore deposit as porphyry ore formation, stockwork and the Cu-Mo-Au element list indicates.&lt;/p&gt;&#xA;&lt;p&gt;Is this a correct line of thinking and if so is it specific enough, do you think?&lt;/p&gt;&#xA;" OwnerUserId="22000" LastEditorUserId="725" LastEditDate="2021-03-24T12:40:53.247" LastActivityDate="2021-03-24T12:43:34.930" Title="Ore Deposit Identification" Tags="|geology|mineralogy|rocks|minerals|economic-geology|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20972" PostTypeId="2" ParentId="20964" CreationDate="2021-03-17T06:19:12.633" Score="3" Body="&lt;p&gt;It looks like a submarine canyon incised into the seafloor and shelf by repeated sediment &amp;quot;flushing&amp;quot;. Given the location, earthquakes probably flush huge quantities of sediments from the low angle plains to the north, through the canyons, and into the abyssal plain to the south. You might find these canyons in any tectonically active seafloor that sees heavy sediment loading from, say, a mountainous tropical region. This one's not that big, compared to &lt;a href=&quot;https://advances.sciencemag.org/content/4/3/eaar3748?rss=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;New Zealand's Hikurangi Channel&lt;/a&gt;, at nearly 700 km.&lt;/p&gt;&#xA;&lt;p&gt;There's another one off the &lt;a href=&quot;https://www.google.com/maps/place/42%C2%B057%2717.6%22N+144%C2%B018%2753.3%22E/@42.6301358,144.4863875,93039m/data=!3m1!1e3!4m5!3m4!1s0x0:0x0!8m2!3d42.9548889!4d144.3148056&quot; rel=&quot;nofollow noreferrer&quot;&gt;SE coast of Hokkaido Island&lt;/a&gt;. What, precisely, locally controls the formation of these canyons is an interesting question.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastEditorUserId="2470" LastEditDate="2021-03-17T07:57:49.480" LastActivityDate="2021-03-17T07:57:49.480" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="20975" PostTypeId="1" AcceptedAnswerId="20976" CreationDate="2021-03-18T06:03:32.960" Score="2" ViewCount="75" Body="&lt;p&gt;It seems that Europe and the Mediterranean Sea have had high seismic activity in last six months. Major events which I remember are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;2020 Aegean Sea earthquake, magnitude of 7.0  Mww&lt;/li&gt;&#xA;&lt;li&gt;29 December 2020:  Petrinja, Croatia, magnitude 6.4 earthquake&lt;/li&gt;&#xA;&lt;li&gt;Many Etna volcano eruptions&lt;/li&gt;&#xA;&lt;li&gt;3 March 2021: Týrnavos, Greece  6.3  Mww&lt;/li&gt;&#xA;&lt;li&gt;Many earthquakes in recent weeks in Iceland and an alert for volcanic eruption&lt;/li&gt;&#xA;&lt;li&gt;Today (18 March 2021): 6.0 Mww earthquake in souther Mediterranean Sea, near Béjaïa, Algeria&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;What could this high seismic activity across Europe tell us?&lt;/p&gt;&#xA;" OwnerUserId="22053" LastEditorUserId="2470" LastEditDate="2021-03-18T08:43:37.203" LastActivityDate="2021-03-18T10:30:02.717" Title="Recent high seismic activity in Europe" Tags="|earthquakes|seismic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20976" PostTypeId="2" ParentId="20975" CreationDate="2021-03-18T10:30:02.717" Score="2" Body="&lt;p&gt;There is a nice tracker for global earthquake activity at &lt;a href=&quot;https://www.volcanodiscovery.com/earthquakes/global-seismic-activity-level.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.volcanodiscovery.com/earthquakes/global-seismic-activity-level.html&lt;/a&gt;, although it doesn't conveniently allow you to look at regional statistics, as opposed to global or national records.&lt;/p&gt;&#xA;&lt;p&gt;At a global level there doesn't seem to be any particular increase in events , although in a quasi random series clustering in time and space isn't unexpected.&lt;/p&gt;&#xA;&lt;p&gt;The perception that there might be an increase is probably a reflection of human and media behaviour; when one event occurs it heightens our interest and the likelihood of noticing other events. The media are far more likely to report a small earthquake occurring in the immediate aftermath of a large earthquake elsewhere in the world, than they would have if it had occurred in isolation.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2021-03-18T10:30:02.717" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20977" PostTypeId="2" ParentId="20953" CreationDate="2021-03-18T16:00:18.967" Score="2" Body="&lt;p&gt;Before the 1960s, the size of the Aral Sea was relatively consistent. However, the Aral Sea went through some &amp;quot;dry spells&amp;quot; during the 1st and 3rd centuries BCE. Going even further back, the Aral Sea dried up during the Early Pleistocene and was &amp;quot;refilled&amp;quot; during the Early Holocene. In other words, the Aral Sea probably looked the same in 1000 as it did in 1950. (Encyclopædia Brittanica)&lt;/p&gt;&#xA;" OwnerUserId="22055" LastActivityDate="2021-03-18T16:00:18.967" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20978" PostTypeId="2" ParentId="18078" CreationDate="2021-03-18T16:33:41.047" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;If an ice shelf collapses, the backpressure disappears. The glaciers that fed into the ice shelf speed up, flowing more quickly out to sea. Glaciers and ice sheets rest on land, so once they flow into the ocean, they contribute to sea-level rise.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;(source: &lt;a href=&quot;https://nsidc.org/cryosphere/quickfacts/iceshelves.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NSIDC&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="22055" LastEditorUserId="2958" LastEditDate="2021-03-19T02:27:56.527" LastActivityDate="2021-03-19T02:27:56.527" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20981" PostTypeId="2" ParentId="20958" CreationDate="2021-03-18T21:17:17.277" Score="1" Body="&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;What is the current capacity of the soil and overburden.  This will depend on the history of rainfall for the previous year or six.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;How fast can that surface absorb water?  If you get 7 inches of rain in one hour (near my brother's house in N.M.) you get a lot more run off than if you get that same 7 inches in 7 days.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;I'm not sure how evaporation potential is determined.  If it's calculated from temperature and relative humidity, it will seriously underestimate actual evaporation.  You would need to model wind and ground level convection.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Time of day of precip is going to matter too.  A small rainfall event on warm earth will mostly evaporate, where the same rain at dawn will soak into the soil.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Vegetation types will matter too: Plants like clover will quickly absorb rainfall and store it internally.  Most trees on the other hand will not absorb moisture through their leaves, and so all of that will evaporate again.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Steep hills will shed water into channels much faster than plains.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Certain rocks (limestone, sandstone) can make a region that there is no surface runoff at all.  (See karst landscape)&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Shape of river channel will make a difference.  If you have lakes and pools, these act as 'spreaders' changing a 3 day deluge into a month of high water.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;When I went canoeing in Northern Saskatchewan every year, I came up with a set of rules for checking routes:&lt;/p&gt;&#xA;&lt;p&gt;200 km2 of water shed:  The canoe would float, but I had to walk.&#xA;1000 km2 of water shed: I could paddle, but I'd be getting in and out a lot.&#xA;5000 km2 of water shed.  I only worried about the places where the river constricted.&lt;/p&gt;&#xA;&lt;p&gt;BUT:  That was empirical observation of one part of the world, one month of the year (trips were in June) with most of the geology being bog and granite. (Laurentian Shield)&lt;/p&gt;&#xA;&lt;p&gt;This is why gauge stations are important.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;" OwnerUserId="13145" LastActivityDate="2021-03-18T21:17:17.277" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20982" PostTypeId="2" ParentId="19815" CreationDate="2021-03-19T02:35:03.780" Score="2" Body="&lt;p&gt;The &lt;code&gt;POLLUTID&lt;/code&gt; key is used to specify some regular options.&lt;/p&gt;&#xA;&lt;p&gt;Some examples:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;code&gt;PM2.5&lt;/code&gt; can only evaluate averages greater than 24 hours (if you try to generate hourly averages it throws an error).&lt;/li&gt;&#xA;&lt;li&gt;&lt;code&gt;NO2&lt;/code&gt; forces the use of options to simulate the conversion of NO&lt;sub&gt;x&lt;/sub&gt; to NO&lt;sub&gt;2&lt;/sub&gt;.&lt;/li&gt;&#xA;&lt;li&gt;&lt;code&gt;SO2&lt;/code&gt; triggers the use of a 4-hour half-life for SO&lt;sub&gt;2&lt;/sub&gt; decay in urban zones.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;All pollutants (gases and particles) are treated similarly, regardless of their weight or molecular density.&lt;/p&gt;&#xA;" OwnerUserId="17863" LastEditorUserId="2470" LastEditDate="2021-03-21T08:47:40.660" LastActivityDate="2021-03-21T08:47:40.660" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20983" PostTypeId="1" CreationDate="2021-03-19T15:19:09.843" Score="5" ViewCount="142" Body="&lt;p&gt;I am a writer, not a scientist of any kind. I live in the SW AZ desert (USA), so we get earthquakes from time to time.  I grew up in southern CA, right next to the San Andreas fault, so I have a cursory &amp;quot;high school geology&amp;quot; understanding of tectonic plates and earthquake forces.  (The schools made sure we understood what was going on and how to prepare for The Big One.)&lt;/p&gt;&#xA;&lt;p&gt;In doing some more research for a writing project, I came across some web sites that showed the progressive subduction of the Farallon plate (for instance: &lt;a href=&quot;https://pubs.usgs.gov/gip/dynamic/Farallon.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://pubs.usgs.gov/gip/dynamic/Farallon.html&lt;/a&gt;).  I'd never known about that one!  These show that all that remains is the Juan de Fuca plate at the north end, and the Rivera and Cocos plates at the south.&lt;/p&gt;&#xA;&lt;p&gt;So now I'm wondering what has happened to the middle?  One web site (and I'm sorry I can't find the link right now) suggested it &amp;quot;folded&amp;quot; and was pushed edge-downward toward the center core.  Other sources seem to suggest it broke apart and the remnants fused with the North American plate.&lt;/p&gt;&#xA;&lt;p&gt;Al of this is in concert with the idea of &amp;quot;the next big one&amp;quot; on the West Coast, where over a hundred years of pent-up friction suddenly releases and the North American and Pacific plates move up to 20 feet.  (Common theories bantered about, based on about 2 inches of movement per year, but unable to move that much for over a hundred years. Feel free to correct, please!!)&lt;/p&gt;&#xA;&lt;p&gt;If the Farallon plate was still solid underneath the NA plate, would it also push the Juan de Fuca, Rivera, and Cocos plates as well?  If the three remnant plates are indeed separate and now caught in between the two larger plates moving opposite directions, would they shear apart?  Or just individually subduct more (which in itself would be quite a violent movement)?&lt;/p&gt;&#xA;&lt;p&gt;If the answers are too complex and what I really need is a better basic understanding of the dynamics of plate movements, I would appreciate any resources you can point me towards.&lt;/p&gt;&#xA;&lt;p&gt;(One terminology question: I keep seeing references to a fault causing earthquakes.  It's actually the other way around, isn't it?  Plate movement causes earthquakes, which creates faults in the crust up where we are?)&lt;/p&gt;&#xA;&lt;p&gt;Thank you!!&lt;/p&gt;&#xA;" OwnerUserId="22062" LastEditorUserId="22062" LastEditDate="2021-03-20T23:08:01.823" LastActivityDate="2023-09-14T03:04:20.677" Title="Farallon plate subducting under North American plate: is it a factor in &quot;the next big one&quot;?" Tags="|plate-tectonics|earthquakes|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20984" PostTypeId="1" CreationDate="2021-03-21T07:17:44.550" Score="1" ViewCount="31" Body="&lt;p&gt;On a barley farm, there are yellow and brown spots on leaf tips.&lt;/p&gt;&#xA;&lt;p&gt;Possible causes:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Some kind of parasite&lt;/li&gt;&#xA;&lt;li&gt;Weather condition&lt;/li&gt;&#xA;&lt;li&gt;Bad seed&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Looks like some farms using the same seed are affected&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;What might be the actual cause? What could be the solution?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kbzpg.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kbzpg.jpg&quot; alt=&quot;leaf&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WjNNs.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WjNNs.jpg&quot; alt=&quot;leaf&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wWypJ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wWypJ.jpg&quot; alt=&quot;leaf&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GOpkY.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GOpkY.jpg&quot; alt=&quot;leaf&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kHAFw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kHAFw.jpg&quot; alt=&quot;leaf&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22068" LastActivityDate="2021-03-21T07:38:11.253" Title="Yellow and brown spots on leaf tip" Tags="|agriculture|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20985" PostTypeId="2" ParentId="20984" CreationDate="2021-03-21T07:38:11.253" Score="2" Body="&lt;p&gt;I would suggest you contact your local government agricultural authority.&lt;/p&gt;&#xA;&lt;p&gt;It looks like the barley crop might be infected with a pathogen, such as a fungus.&lt;/p&gt;&#xA;&lt;p&gt;It could be a form of &lt;a href=&quot;https://agriculture.vic.gov.au/biosecurity/plant-diseases/grain-pulses-and-cereal-diseases/rusts-of-barley&quot; rel=&quot;nofollow noreferrer&quot;&gt;barley rust&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Different regions of the world have different &lt;a href=&quot;https://grdc.com.au/resources-and-publications/groundcover/ground-cover-issue-105-july-august-2013/barley-rust-diseases-in-focus&quot; rel=&quot;nofollow noreferrer&quot;&gt;forms of rust&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Your local agricultural authority should be notified in case the outbreak poses a bio security risk in your region.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-03-21T07:38:11.253" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20986" PostTypeId="1" AcceptedAnswerId="20988" CreationDate="2021-03-21T15:24:06.393" Score="2" ViewCount="73" Body="&lt;p&gt;Suppose a violent, dangerous composite volcano whose eruptions destroy the nearby countryside exists. Would it be possible for this volcano to change such that future eruptions are less violent, and less dangerous to anyone living nearby?&lt;/p&gt;&#xA;&lt;p&gt;Alternatively, would it be possible to terraform the volcano to make its eruptions less dangerous?&lt;/p&gt;&#xA;" OwnerUserId="22069" LastEditorUserId="725" LastEditDate="2021-03-24T12:36:32.003" LastActivityDate="2021-03-24T19:57:52.920" Title="Is it possible for an active volcano to become less violent over time?" Tags="|volcanology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20987" PostTypeId="1" AcceptedAnswerId="20989" CreationDate="2021-03-22T02:08:34.277" Score="2" ViewCount="250" Body="&lt;p&gt;Japan seems to get a surprising amount of snow in winter, compared to other places that are as cold or colder.&lt;/p&gt;&#xA;&lt;p&gt;The snow seems to be concentrated on the west side of the country, which suggests the lake effect, only with the sea instead of a lake; the prevailing wind from the west brings air that has picked up moisture going over the sea, and the moisture freezes and falls as snow.&lt;/p&gt;&#xA;&lt;p&gt;But why then do places like Oregon and Ireland not get so much snow, despite being similarly on the receiving end of moist air?&lt;/p&gt;&#xA;&lt;p&gt;Those places have an entire ocean to the west, as opposed to Japan which has a narrow sea and then a continent. Conjecture: it's the combination that does the trick. Air blowing over the continent becomes very cold, then blows over the narrow sea and picks up moisture, which then freezes out. So to get maximum snow, you need a continent and then a narrow sea or lake, followed by the land which is to receive the snow.&lt;/p&gt;&#xA;&lt;p&gt;Is that conjecture correct? Or if not, what is the reason for the amount of snow?&lt;/p&gt;&#xA;" OwnerUserId="7911" LastActivityDate="2021-03-23T07:56:46.980" Title="Why does Japan get so much snow?" Tags="|meteorology|precipitation|snow|japan|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20988" PostTypeId="2" ParentId="20986" CreationDate="2021-03-22T03:40:53.090" Score="4" Body="&lt;p&gt;The ultimate fate of all active volcanos is to become extinct volcanos, and eventually, objects that are barely recognizable (or not recognizable at all) as extinct volcanos.&lt;/p&gt;&#xA;&lt;p&gt;This process from pre-volcano to active volcano to extinct volcano to barely recognizable extinct volcano takes a long time, even by geological standards of &amp;quot;a long time&amp;quot;. The oldest elements of the Hawaiian–Emperor seamount chain predate the Chicxulub crater, and even those oldest elements are easily recognizable as extinct volcanos. Active volcanos are active for only short periods of time (short by geological standards), a few hundred thousand years at most. That of course is a very, very long period of time by human standards.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Alternatively, would it be possible to terraform the volcano to make its eruptions less dangerous?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Consider the follow hypothetical doctor-patient conversation: &amp;quot;Doctor, it hurts when I do this!&amp;quot; (The patient then bonk himself on the head.) The doctor's response is simple: &amp;quot;Don't do that then.&amp;quot; The easiest way to do this with regard to active volcanos is to stop having humans live near active volcanos. What is feasible is to vastly improve the ability to predict when volcanos will erupt. The state of the art in this regard is rather lousy (the state of the practice is lousier still),&lt;/p&gt;&#xA;&lt;p&gt;That is not feasible; there are too many humans who already live near active volcanos. Terraforming also is not feasible. While the amount of energy released by volcanos per year is a lot less (orders of magnitude less) than the amount of energy the Earth receives from the Sun, it is still orders of magnitude higher than the amount of energy consumed by humanity. To make matters worse, that human consumption is widely dispersed while volcanic energy is concentrated in a few places.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2021-03-22T03:40:53.090" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20989" PostTypeId="2" ParentId="20987" CreationDate="2021-03-22T10:43:22.773" Score="2" Body="&lt;p&gt;From my understanding, you are thinking along the right lines but also need to take mountains into account.&lt;/p&gt;&#xA;&lt;p&gt;Ireland's mountains are lower than Japans. I &lt;em&gt;think&lt;/em&gt; that Japan's mountains are a similar height to Oregon's but the high mountains are closer to the coast in Japan. (I don't know either area well, so this statement could be wrong.)&lt;/p&gt;&#xA;&lt;p&gt;Another thing to consider is that in winter, &lt;a href=&quot;https://www.eumetsat.int/winter-convection-over-uk-snowy-european-mountains&quot; rel=&quot;nofollow noreferrer&quot;&gt;convective showers are common over the sea&lt;/a&gt;. A longer sea track will have more showers and therefore more mixing of the atmosphere, raising the temperature of the air mass.&lt;/p&gt;&#xA;&lt;p&gt;Winter convection cuts off over land, but showers can penetrate inland a little with the momentum they already have. The closeness of the mountains to the coast in Japan, as well as their height, will give more &lt;a href=&quot;https://en.wikipedia.org/wiki/Orography#Orographic_precipitation&quot; rel=&quot;nofollow noreferrer&quot;&gt;orographic enhancement&lt;/a&gt; to the amount of precipitation as well as possibly reinvigorating the unstable convection by forcing it to rise. Ireland's lower lying status won't have this effect as much.&lt;/p&gt;&#xA;&lt;p&gt;Oregon has two ranges of mountains, the lower Coastal Range (&amp;lt;1000m) and the higher but 150km inland Cascades (~3000m). The Coastal Range has a similar height to the Irish mountains but are longer in their extent. The orographic enhancement of the Coastal Range will be much less than in Japan. The Cascades will then be in a rain shadow as the air will be less humid downwind of the Coastal Range. While the Cascades still cause orographic enhancement, this is nowhere near as much as if the Cascades were by the coast, which in Japan they effectively are. You can see this effect on the annual average precipitation map of Oregon:&#xA;&lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/8/80/Oregon_Average_Annual_Precipitation_%281961-1990%29_Map.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oWQ4n.png&quot; width=&quot;450&quot; alt=&quot;Average Annual Precipitation map of Oregon showing higher rates in the Coastal Range than further inland in the Cascades.&quot;/&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As an aside, I had wondered if the Sea of Japan might be warmer than around Oregon and Ireland; this would provide more heat, moisture and instability to the air reaching Japan. I had a quick look at &lt;a href=&quot;https://iridl.ldeo.columbia.edu/maproom/Global/Ocean_Temp/Monthly_Temp.html?T=Feb%202019&quot; rel=&quot;nofollow noreferrer&quot;&gt;February sea surface temperatures&lt;/a&gt;, and they seem broadly comparable to the other areas, at least for the past three years, so this enhancement mechanism seems unlikely. February appears to be the &lt;a href=&quot;https://www.japan-guide.com/e/e2265.html#:%7E:text=The%20snow%20season%20in%20Japan,the%20peak%20being%20in%20February.&quot; rel=&quot;nofollow noreferrer&quot;&gt;month that Japan gets the most snow&lt;/a&gt;, although I'm not sure if that's talking about peak snowfall or peak accumulation.&lt;/p&gt;&#xA;&lt;p&gt;I found a few articles about Japan's snow online:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.nationalgeographic.com/science/article/worlds-snowiest-place-northwestern-japan-melting-climate-change#:%7E:text=Source%20of%20the%20Snow&amp;amp;text=The%20coastal%20mountains%20in%20Japan,bury%20even%20Tokyo%20in%20snow.&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Geographic: The world's snowiest place is starting to melt&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.ski.com/blog/why-is-there-so-much-snow-in-japan/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ski.com: Why is there so much snow in Japan?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="20542" LastEditorUserId="20542" LastEditDate="2021-03-23T07:56:46.980" LastActivityDate="2021-03-23T07:56:46.980" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="20990" PostTypeId="2" ParentId="18078" CreationDate="2021-03-22T12:56:03.017" Score="4" Body="&lt;p&gt;The word collapse is not appropriate in the case of a &lt;em&gt;hanging glacier&lt;/em&gt; such as the one you mention in your question. A hanging glacier is a glacier that terminates at a cliff edge. Since glacier ice is constantly moving towards the cliff, the terminus will occasionally lose sufficient support and detach from the glacier causing an &lt;em&gt;ice avalanche&lt;/em&gt;. As long as the glacier feeds ice to the cliff edge ice avalanches will continue to occur. How often will largely depend on the ice velocity moving ice towards the cliff edge. This is thus a natural behaviour and not a collapse, or at least not named collapse in glaciology.&lt;/p&gt;&#xA;&lt;p&gt;The word collapse is not a scientific term and does not have a unique definition in glaciology. In the case of an ice shelf that suddenly breaks apart such as the Larsen B (Rott et al. 1996) the term collapse has been used in articles. In this case the event was sudden and the entire ice shelf broke up and was lost during a few months. At the same time collapse is commonly used to describe other phenomena such as the loss of an ice sheet or part of an ice sheet (for example, Brendryen et al., 2020). Such a process is much slower than the ice shelf collapse, perhaps lasting many hundreds or thousands of years. But the word is used because it describes an irreversible event or development.&lt;/p&gt;&#xA;&lt;p&gt;So coming back to the hanging glacier, its avalanches is an ongoing process and the word collapse gives the wrong impression. The glacier is not collapsing. Given climate warming the glacier will likely decrease in size and the avalanching change, possibly stop depending on the bedrock morphology on which the glacier sits. If the climate warming causes the glacier to completely melt away, then that could be considered a collapse of that glacier. But when you read different scientific articles on glaciers you will see the word used in many different ways so a tricky word to use in a good and consistent way.&lt;/p&gt;&#xA;&lt;p&gt;References&lt;/p&gt;&#xA;&lt;p&gt;Helmut Rott, Pedro Skvarca, Thomas Nagler, 1996 &lt;a href=&quot;https://doi.org/10.1126/science.271.5250.788&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rapid Collapse of Northern Larsen Ice Shelf, Antarctica&lt;/a&gt;. Science, 271 (5250) 788-792&lt;/p&gt;&#xA;&lt;p&gt;Brendryen, J., Haflidason, H., Yokoyama, Y. et al. 2020 &lt;a href=&quot;https://doi.org/10.1038/s41561-020-0567-4&quot; rel=&quot;nofollow noreferrer&quot;&gt;Eurasian Ice Sheet collapse was a major source of Meltwater Pulse 1A 14,600 years ago&lt;/a&gt;. Nat. Geosci. 13, 363–368.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="725" LastEditDate="2021-03-29T04:46:28.657" LastActivityDate="2021-03-29T04:46:28.657" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20991" PostTypeId="1" CreationDate="2021-03-22T14:36:20.413" Score="2" ViewCount="151" Body="&lt;p&gt;If you want to know what the actual emissivity of water is (which is terribly important to even get an idea what size the GHE has!), you can google. Regrettably you will get all kinds of results, so that you are not getting any smarter. So I had to explore the question myself.&lt;/p&gt;&#xA;&lt;p&gt;I used the &lt;a href=&quot;https://en.wikipedia.org/wiki/Fresnel_equations#Power_(intensity)_reflection_and_transmission_coefficients&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fresnel equation&lt;/a&gt; from Wikipedia (and &amp;quot;translated&amp;quot; it into Excel):&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;Rs=(($B$1*COS(C5)-$B$2*(1-($B$1/$B$2*SIN(C5))^2)^0.5)/($B$1*COS(C5)+$B$2*(1-($B$1/$B$2*SIN(C5))^2)^0.5))^2&#xA;Rp=(($B$1*(1-($B$1/$B$2*SIN(C5))^2)^0.5-$B$2*COS(C5))/($B$1*(1-($B$1/$B$2*SIN(C5))^2)^0.5+$B$2*COS(C5)))^2&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;With&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;$B$1 = N1&#xA;$B$2 = N2&#xA;C5, C6.. = the respective angle /180 * PI()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;And then there is &lt;a href=&quot;https://refractiveindex.info/?shelf=main&amp;amp;book=H2O&amp;amp;page=Hale&quot; rel=&quot;nofollow noreferrer&quot;&gt;this very useful site&lt;/a&gt; that gives you information on the optical properties of water.&lt;/p&gt;&#xA;&lt;p&gt;Now if I enter a wavelength of &amp;quot;1&amp;quot; I get a refractive index of n = 1.327. In my calculation I use this as N2 = 1.327 with N1 = 1 (for air). If you scroll down on this page there is a section called &amp;quot;Reflection calculator&amp;quot; that gives you the calculated result of light reflected on the surface of water, at the given wavelength for any given angle.&lt;/p&gt;&#xA;&lt;p&gt;The great thing is, that when I compare these results (those in my excel sheet and those on this site) they perfectly match, for every angle, for at least 6 digits. Naturally that gave me the confidence that I did everything right.&lt;/p&gt;&#xA;&lt;p&gt;Just recently I stumbled over a problem. For instance I can enter a wavelength of 16.039, which incidentally also has a refractive index of n = 1.327. In my excel sheet the outcome will be the same, as the refractive index is the only relevant input. But now the &amp;quot;Reflection calculator&amp;quot; gives me a very different result which does not match my excel results.&lt;/p&gt;&#xA;&lt;p&gt;So the logic suggests the formula they use there is after all different the formula I described above and includes another parameter. I assume that parameter might be the &amp;quot;extinction coefficient&amp;quot; k, which is very small at a wavelength of 1, but quite substantial at 16.039.&lt;/p&gt;&#xA;&lt;p&gt;Do you have any idea what the formula used on this site might actually look like?&lt;/p&gt;&#xA;" OwnerUserId="22075" LastEditorUserId="2958" LastEditDate="2021-03-24T14:35:01.977" LastActivityDate="2021-03-24T14:35:01.977" Title="Fresnel equations &amp; emissivity of water" Tags="|solar-terrestrial-physics|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="20992" PostTypeId="1" CreationDate="2021-03-22T16:34:31.240" Score="1" ViewCount="76" Body="&lt;p&gt;I am a high school senior studying in a local school in Bangladesh. My passion is to study oceans &amp;amp; marine life. The drive of getting higher education in Oceanography has turned into ardent compassion for me. I am, therefore, seeking insightful &amp;amp; important pieces of information regarding which universities would be best for higher education in Oceanography.&#xA;Your guidance &amp;amp; help is much wanted &amp;amp; would be highly appreciated.&#xA;&amp;lt;3&lt;/p&gt;&#xA;" OwnerUserId="22078" LastActivityDate="2021-03-23T15:30:36.023" Title="Which universities are best for studying Oceanography as an undergrad?" Tags="|oceanography|" AnswerCount="1" CommentCount="1" ClosedDate="2021-03-24T05:50:49.013" ContentLicense="CC BY-SA 4.0" />
  <row Id="20993" PostTypeId="1" AcceptedAnswerId="20998" CreationDate="2021-03-22T17:13:54.207" Score="4" ViewCount="508" Body="&lt;p&gt;Because there is so much pressure in the earth's core, the inner core is solid but what happens if you manage to add some water in the inner core or near it. Does the pressure make the water solid or does it evaporate? do iron and nickel only turn solid under pressure?&lt;/p&gt;&#xA;" OwnerUserId="21926" LastActivityDate="2021-03-29T19:21:57.057" Title="Can there be ice in the core because of pressure?" Tags="|core|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20994" PostTypeId="2" ParentId="20992" CreationDate="2021-03-23T15:30:36.023" Score="3" Body="&lt;p&gt;I noticed that there is a push to close the question, and I get why. But I do think that guidance towards a university is still important, even if it does not fit the Earth Science SE guidelines. So here is my answer (as someone who does not study oceanography, rather as a meteorologist): It depends.&lt;/p&gt;&#xA;&lt;p&gt;What I have found is that the question you should ask is not 'what is the best,' rather 'what is the best &lt;em&gt;for me&lt;/em&gt;?' You may want to learn from the best, but you might end up miserable. What can you afford? How far are you willing to travel for your degree? What aspects of oceanography are you interested in -- chemistry, climatology, biology, geology, etc.? Presumably, different universities will emphasize different specialties. Look at what the faculty research, and you will find what&lt;/p&gt;&#xA;&lt;p&gt;Knowledge is knowledge. With solid reading skill and good resources, you can probably teach yourself enough without needing a degree. If it is just a passion, I would recommend that route. If it is what you want as a career, go to university and get the degree.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-03-23T15:30:36.023" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="20996" PostTypeId="2" ParentId="18078" CreationDate="2021-03-24T11:24:34.407" Score="-2" Body="&lt;p&gt;Glacier collapse means that the temperature of the Earth is gradually increasing due to global warming, due to which the glaciers are also melting slowly, in the last 100 years, the temperature of the Earth has increased by about 1 °.  By the end of this century, the temperature will increase by 5 °.  And only about 20% of the polar ice will survive.&lt;/p&gt;&#xA;" OwnerUserId="22089" LastEditorUserId="2958" LastEditDate="2021-03-24T13:58:20.890" LastActivityDate="2021-03-24T13:58:20.890" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="20997" PostTypeId="2" ParentId="20969" CreationDate="2021-03-24T12:43:34.930" Score="2" Body="&lt;p&gt;This is the classic description of a porphyry copper-molybdenum deposit.&lt;/p&gt;&#xA;&lt;p&gt;What happens is that there is a magmatic intrusion (the porphyry), which then solidifies. When it solidifies, it expels acidic hydrothermal fluids which carry metals in them - most often copper (represented by chalcopyrite) but also sometimes molybdenum (represented by molybdenite).&lt;/p&gt;&#xA;&lt;p&gt;Once the fluids hit solid rocks, they react with it, and become neutralised. The carrying capacity of the fluids diminish, and they deposit the metals into the minerals you observe. The solid rocks can be pretty much anything. It can be the porphyry itself, another porphyry that happened to be around, sedimentary rocks, or whatever.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-03-24T12:43:34.930" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20998" PostTypeId="2" ParentId="20993" CreationDate="2021-03-24T13:02:24.990" Score="7" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;what happens if you manage to add some water in the inner core or near it.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It will probably react with the solid iron to form iron (oxy)hydride:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Our observations indicate that H2O is likely introduced into the deep Earth through reaction between iron and water during the accretion and separation of the metallic core. Additionally, reaction between Fe and H2O would occur at the core‐mantle boundary, given water released from hydrous subducting slabs that intersect with the metallic core. Accumulation of volatile‐bearing iron compounds may provide new insights into the enigmatic seismic structures observed at the base of the lower mantle.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;(source: &lt;a href=&quot;https://doi.org/10.1002/2017GL075720&quot; rel=&quot;noreferrer&quot;&gt;https://doi.org/10.1002/2017GL075720&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;In other words, the question of whether the water would be ice, liquid, or vapour is a non-question because water as molecules of H&lt;sub&gt;2&lt;/sub&gt;O would cease to exist.&lt;/p&gt;&#xA;&lt;p&gt;You don't need the core for this. Take water, put it on a piece of iron, and the water would be absorbed into the iron in the form of rust:&#xA;&lt;span class=&quot;math-container&quot;&gt;$\ce{Fe + 0.5H2O + 0.5O2 = FeOOH}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Regarding the question of what would happen to just water if you would put it in core-like pressures and temperatures, the answer is simple: we don't know. I don't think anyone attempted that experimentally. It will probably not be a gas - pressures are way too high for that. Since the melting point of H&lt;sub&gt;2&lt;/sub&gt;O is much lower than that of iron, I suspect it will be a liquid.&lt;/p&gt;&#xA;&lt;p&gt;Something from the comments:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;On quora, they said that high pressure would lower the melting point of ice, not as expected, probably making it vapor&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is only relevant at relatively low temperatures because of the anomalous crystal structure of ice. For most compounds, you need greater temperature to melt something which is at pressure. It's actually opposite for water, and closely related to the fact that ice floats on water (which is very counter-intuitive - usually solids are denser than liquids). But at high temperatures, of hundreds and thousands of degrees, water starts to behave normally under high pressure.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-03-24T13:02:24.990" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="20999" PostTypeId="2" ParentId="20993" CreationDate="2021-03-24T17:17:44.147" Score="1" Body="&lt;p&gt;To find an answer to this question, we need to look back at the formation process of the Earth's Core. Simply put, the Layered structure of Earth is a result of density stratification. Denser metallic elements which could not form complexes sunk to the center to form the core of the Earth. Hydrogen being the lightest element, it won't be practically available in the Earth's core to form water. We can convincingly say that there is no water in the Earth's core which rules out the possibility of water being present as a solid, liquid or vapor state.&lt;/p&gt;&#xA;&lt;p&gt;Even, if we suppose water is present in the core somehow. It will possibly in the supercritical state or it would have formed complexes with other metalic elements.&lt;/p&gt;&#xA;" OwnerUserId="22092" LastActivityDate="2021-03-24T17:17:44.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21000" PostTypeId="2" ParentId="20986" CreationDate="2021-03-24T17:53:23.383" Score="1" Body="&lt;p&gt;I'm gonna answer this part of the question.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Alternatively, &lt;strong&gt;would it be possible to terraform the volcano to make its eruptions less dangerous?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;If there was the infrastructure and if we are smart enough. Take for example then-president &lt;a href=&quot;https://www.axios.com/trump-nuclear-bombs-hurricanes-97231f38-2394-4120-a3fa-8c9cf0e3f51c.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Trump suggesting nuking the eye of Hurricanes&lt;/a&gt;, but the nuclear fallout would move with the remaining Hurricane, which could cause devastating consequences. We should not apply the same thinking and terminology, that President Trump thought in slowing eruptions or making them safer.&lt;/p&gt;&#xA;&lt;p&gt;Bombing the center of an active volcano erupting from a logical Perspective would seem workable and cool, hey but if you actually do this with a normal bomb or missile this could make the eruption worse (Hence, the bomb will explode with the volcano spreading more projectiles magma or ash)&lt;/p&gt;&#xA;&lt;h2&gt;Terraforming the Volcano&lt;/h2&gt;&#xA;&lt;p&gt;Before an eruption occurs, we could &amp;quot;terraform&amp;quot; the volcano to slow the progression of Lava or possibly reduce the explosion intensity. we could build sturdy, barricaded walls with materials with high melting points, we could order an evacuation.&lt;/p&gt;&#xA;&lt;p&gt;We cant simply use water to extinguish and solidify the water because magma below the stone-looking lava can Bulldoze around, destroying everything.&lt;/p&gt;&#xA;" OwnerUserId="21926" LastEditorUserId="21926" LastEditDate="2021-03-24T19:57:52.920" LastActivityDate="2021-03-24T19:57:52.920" CommentCount="5" CommunityOwnedDate="2021-03-24T19:57:52.920" ContentLicense="CC BY-SA 4.0" />
  <row Id="21001" PostTypeId="1" AcceptedAnswerId="21004" CreationDate="2021-03-24T17:59:46.797" Score="1" ViewCount="48" Body="&lt;p&gt;What are the different ways permeability of a core specimen can be determined accurately for fluids with different viscosities and their mixtures?&lt;/p&gt;&#xA;" OwnerUserId="22092" LastActivityDate="2021-03-25T09:59:40.600" Title="Permeability test" Tags="|geology|sedimentology|geoengineering|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21003" PostTypeId="1" CreationDate="2021-03-25T09:54:09.643" Score="5" ViewCount="358" Body="&lt;p&gt;Was Zealandia above sea level during the last ice age? Like how Sahul or Sundaland were?&lt;/p&gt;&#xA;" OwnerUserId="22103" LastActivityDate="2021-03-26T06:07:56.667" Title="Was Zealandia above water during the last Ice age?" Tags="|sea-level|ice-age|continental-crust|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21004" PostTypeId="2" ParentId="21001" CreationDate="2021-03-25T09:59:40.600" Score="0" Body="&lt;p&gt;Strictly defined, permeability is an intrinsic property of a rock or soil, and is thus independent of the viscosity of the gas or liquid that is flowing through. Hydraulic conductivity is the equivalent measure that takes into account viscosity and fluid density. So if you have measured permeability you can calculate hydraulic conductivity for, in concept at least, any liquid.&lt;/p&gt;&#xA;&lt;p&gt;Laboratory measurements of permeability involve passing a gas or fluid through a sample and measuring the pressure drop across the sample and the rate of flow. The characteristics of the gas or fluid are used to back calculate permeability from the measured hydraulic conductivity. Gas or fluid characteristics do influence testing - and a range of empirical corrections would be applied to account for these) (&lt;a href=&quot;https://petrowiki.spe.org/Corrections_to_core_measurements_of_permeability&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://petrowiki.spe.org/Corrections_to_core_measurements_of_permeability&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2021-03-25T09:59:40.600" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21006" PostTypeId="2" ParentId="19532" CreationDate="2021-03-25T12:12:57.813" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;I'm studying Earth Science right now, and I found conflicting reporting re: the formation of the Grand Canyon; whether it was formed singularly by the Colorado River over millions of years, or if it was formed by other processes with the river only filling into it relatively recently.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Yes, it was formed by other processes with the river only excavating into it relatively recently.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.nps.gov/grca/index.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Grand Canyon National Park Service&lt;/a&gt; describe the events involved in the formation of the Grand Canyon widely. The sequence of events was as follows:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Emplacement of an igneous and metamorphic body.&lt;/li&gt;&#xA;&lt;li&gt;Sedimentation over the igneous and metamorphic body.&lt;/li&gt;&#xA;&lt;li&gt;Uptlift of the complex by tectonic forces forming Colorado Plateau.&lt;/li&gt;&#xA;&lt;li&gt;Excavation of the Plateau by Colorado River.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nps.gov/grca/learn/nature/grca-geology.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Read full explanation at Grand Canyon National Park website&lt;/strong&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-03-26T06:50:02.463" LastActivityDate="2021-03-26T06:50:02.463" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21008" PostTypeId="2" ParentId="20948" CreationDate="2021-03-25T12:48:06.770" Score="0" Body="&lt;p&gt;&lt;strong&gt;Continental Crust&lt;/strong&gt; forms because of continual volcanic magma flow and pressure, erosion takes over a period of hundreds to millions of years to completely weather some object. Along with that, tectonic plates can smash into each other to form a continental crust and do land-building (The Himalayas is an exemple)&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;As with oceanic crust, continental crust is created by plate tectonics. At convergent plate boundaries, where tectonic plates crash into each other, continental crust is thrust up in the process of orogeny, or mountain-building. For this reason, the thickest parts of continental crust are at the world’s tallest mountain ranges. Like icebergs, the tall peaks of the Himalayas and the Andes are only part of the region’s continental crust—the crust extends unevenly below the Earth as well as soaring into the atmosphere.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;“Crust” describes  the outermost shell of a terrestrial planet. Our planet’s thin, 40-kilometer (25-mile) deep crust—just 1% of Earth’s mass—contains all known life in the universe.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Earth has three layers: the crust, the mantle, and the core. The crust is made of solid rocks and minerals. Beneath the crust is the mantle, which is also mostly solid rocks and minerals, but punctuated by malleable areas of semi-solid magma. At the center of the Earth is a hot, dense metal core.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Earth’s layers constantly interact with each other, and the crust and upper portion of the mantle are part of a single geologic unit called the lithosphere. The lithosphere’s depth varies, and the Mohorovicic discontinuity (the Moho)—the boundary between the mantle and crust—does not exist at a uniform depth. Isostasy describes the physical, chemical, and mechanical differences between the mantle and crust that allow the crust to “float” on the more malleable mantle. Not all regions of Earth are balanced in isostatic equilibrium. Isostatic equilibrium depends on the density and thickness of the crust, and the dynamic forces at work in the mantle.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Just as the depth of the crust varies, so does its temperature. The upper crust withstands the ambient temperature of the atmosphere or ocean—hot in arid deserts and freezing in ocean trenches. Near the Moho, the temperature of the crust ranges from 200° Celsius (392° Fahrenheit) to 400° Celsius (752° Fahrenheit).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Crafting the Crust&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Billions of years ago, the planetary blob that would become the Earth started out as a hot, viscous ball of rock. The heaviest material, mostly iron and nickel, sank to the center of the new planet and became its core. The molten material that surrounded the core was the early mantle.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Over millions of years, the mantle cooled. Water trapped inside minerals erupted with lava, a process called “outgassing.” As more water was outgassed, the mantle solidified. Materials that initially stayed in their liquid phase during this process, called “incompatible elements,” ultimately became Earth’s brittle crust.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="21926" LastActivityDate="2021-03-25T12:48:06.770" CommentCount="1" CommunityOwnedDate="2021-03-25T12:48:06.770" ContentLicense="CC BY-SA 4.0" />
  <row Id="21009" PostTypeId="1" AcceptedAnswerId="21011" CreationDate="2021-03-25T13:37:07.410" Score="2" ViewCount="36" Body="&lt;p&gt;We have an Axioscope microscope and planning to install a Nikon D5300 camera on top of it. The software I looked up, is DigiCam Control. The downside is we cannot add scale by default. The scale has to be calibrated for each slide. We capture lots of photos, so calibrating the scale each time we change the sample is waste of time. Does anybody have any idea regarding this issue?&lt;/p&gt;&#xA;" OwnerUserId="21399" LastActivityDate="2021-03-25T21:20:41.067" Title="How to add scale in DSLR plus microscope set up by default?" Tags="|geology|measurements|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21011" PostTypeId="2" ParentId="21009" CreationDate="2021-03-25T21:20:41.067" Score="4" Body="&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Select the objectives you want to use on your microscope altogether with your camera.  If the camera is not a permanent installation, ensure that the mount reliably establishes again and again the same position and alignment in respect to the optical axis of the microscope.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;See if your group has a stage micrometer, a slide with fine regular markings:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/J8Z92.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/J8Z92.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.microscopy-uk.org.uk/mag/indexmag.html?http://www.microscopy-uk.org.uk/mag/artoct15/dw-micrometer.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;credit&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;If not purchased altogether with the microscope (&lt;a href=&quot;https://www.gtvision.co.uk/Micrometer-Glass-Slide-for-Microscope-Calibration-1mm-Horizontal-Scale-100-divisions-10um-intervals&quot; rel=&quot;nofollow noreferrer&quot;&gt;one other source&lt;/a&gt;), or lost during a move of the group you work in, see if an other group in your school active in microscopy may lend you one.  It may be in geology, but equally in (analytical) chemistry, biology, histology, (laser) physics / optics, etc.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Identify a reliable protocol to get hold of the images recorded by your camera to be fed into a suitable software e.g., &lt;a href=&quot;https://imagej.net/Welcome&quot; rel=&quot;nofollow noreferrer&quot;&gt;ImageJ&lt;/a&gt; / &lt;a href=&quot;https://fiji.sc/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fiji&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Take a good photograph with your camera mounted on the microscope observing the micrometer plate, starting with a low magnification.  For once, you have to count the pixels to &lt;em&gt;calibrate profiles&lt;/em&gt; for a given combination of objective, inner optics, and mounted sensor / camera. But today, you may get assistance by the software's plugin (&lt;a href=&quot;https://github.com/demisjohn/Microscope-Measurement-Tools&quot; rel=&quot;nofollow noreferrer&quot;&gt;example&lt;/a&gt;, &lt;a href=&quot;https://github.com/demisjohn/Microscope-Measurement-Tools/blob/master/Microscope%20Meas.%20-%20Calibration%20instructions.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;documentation&lt;/a&gt;, &lt;a href=&quot;https://www.youtube.com/watch?v=6dGAFawBDMU&quot; rel=&quot;nofollow noreferrer&quot;&gt;tutorial video&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="18990" LastActivityDate="2021-03-25T21:20:41.067" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21012" PostTypeId="2" ParentId="19690" CreationDate="2021-03-26T02:24:56.620" Score="0" Body="&lt;p&gt;No! There was never a claim that temperatures rose after 9/11. The suggestion was only about an increased temperature spread, which is definitely true. Not that it could be told from post 9/11 observation for sure, but there is more research on the subject which shows contrails reduce the daily temperature spread. As to be expected anyway.&lt;/p&gt;&#xA;&lt;p&gt;However the overall effect of contrails, according to the IPCC, is positive! So contrails are warming Earth. Yet it must be said, that the IPCC rates this effect as minimal (+0.01W/m2 in 2004 for linear contrails). If that is true (and I doubt it is), a reduction in contrails would cause non-detectable cooling.&lt;/p&gt;&#xA;" OwnerUserId="22075" LastActivityDate="2021-03-26T02:24:56.620" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21013" PostTypeId="2" ParentId="18953" CreationDate="2021-03-26T02:57:18.490" Score="0" Body="&lt;p&gt;I am doing some calculations on this question myself. The atmospheric lapse rate is about 6.5K/1000m. The adiabatic lapse rate is 9.8K/1000 and the dry lapse rate of the naturally unstable atmosphere of Earth should even be 10.8 K. So arguably the constant transport of latent heat by vapor from the surface into the atmosphere is reducing the lapse rate by some 4.3K/1000m. Without a doubt the GHE would be much larger if it was not for the latent heat provided by vapor.&lt;/p&gt;&#xA;&lt;p&gt;The GHE itself is a function of the emission temperature, which again is a function of the emission altitude. Vapor increases this emission altitude, which is why it is considered a GHG, the most significant one actually.&lt;/p&gt;&#xA;&lt;p&gt;We need to ask what size GHE has (not 33 K, but less), what bigger size it counterfactually had without latent heat and a lapse rate of 10.8 K, determine the share of vapor in this case, and compare it to the (negative) effect of latent heat. Depending on what is bigger, vapor is either a GHG or an anti-GHG. From all the modelling so far I get definitely the latter result.&lt;/p&gt;&#xA;" OwnerUserId="22075" LastEditorUserId="2470" LastEditDate="2021-12-22T23:12:22.913" LastActivityDate="2021-12-22T23:12:22.913" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21015" PostTypeId="2" ParentId="21003" CreationDate="2021-03-26T06:07:56.667" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Was Zealandia above water during the last Ice age?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;For the most part, no.&lt;/p&gt;&#xA;&lt;p&gt;New Zealand's North and South Islands likely would have been connected, New Caledonia and other currently existing islands would have been larger, and some now-submerged areas would have been isolated islands that barely poked above the lower sea level at the time of peak glaciation. However, the vast majority of Zealandia is currently over a kilometer beneath the current sea level, which means that it was over 800 meters below sea level during the peak of the most recent glaciation.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2021-03-26T06:07:56.667" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21016" PostTypeId="1" CreationDate="2021-03-26T06:36:34.453" Score="2" ViewCount="67" Body="&lt;p&gt;I need to install ESMF-5.2.0rp3 version. I have downloaded it from &lt;a href=&quot;https://github.com/esmf-org/esmf/releases/tag/ESMF_5_2_0rp3&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://github.com/esmf-org/esmf/releases/tag/ESMF_5_2_0rp3&lt;/a&gt;. Also I installed the following prerequisites: Fortran95, GCC &amp;amp; C++ 7.5.0, netcdf-bin, libnetcdf-dev, libnetcdff-dev, Open MPI 3.1.1, LAPACK 3.9.0, Perl v5.26.1 and GNU Make 4.1.&lt;/p&gt;&#xA;&lt;p&gt;Building of ESMF using &lt;code&gt;make all&lt;/code&gt; failing and shows the following error in terminal&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;/home/user/esmf-ESMF_5_2_0rp3/src/Superstructure/WebServices/src/ESMCI_WebServNetEsmfServer.C:1798:31: error: no match for ‘operator==’ (operand types are ‘std::fstream {aka std::basic_fstream&amp;lt;char&amp;gt;}’ and ‘long int’)&#xA;  if ((fin == NULL)  ||  (fout == NULL))&#xA;                               ^&#xA;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;The output of &lt;code&gt;make all&lt;/code&gt; is large so I can't paste it here. Finally the building interrupted by showing the following last lines&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;/usr/include/c++/7/bits/stl_iterator.h:302:5: note:   template argument deduction/substitution failed:&#xA;In file included from /usr/include/rpc/netdb.h:42:0,&#xA;                 from /usr/include/netdb.h:32,&#xA;                 from /home/user/esmf-ESMF_5_2_0rp3/src/Superstructure/WebServices/src/ESMCI_WebServNetEsmfServer.C:31:&#xA;/home/user/esmf-ESMF_5_2_0rp3/src/Superstructure/WebServices/src/ESMCI_WebServNetEsmfServer.C:1798:34: note:   ‘std::fstream {aka std::basic_fstream&amp;lt;char&amp;gt;}’ is not derived from ‘const std::reverse_iterator&amp;lt;_Iterator&amp;gt;’&#xA;  if ((fin == NULL)  ||  (fout == NULL))&#xA;                                  ^&#xA;In file included from /usr/include/c++/7/bits/stl_algobase.h:64:0,&#xA;                 from /usr/include/c++/7/bits/char_traits.h:39,&#xA;                 from /usr/include/c++/7/string:40,&#xA;                 from /home/user/esmf-ESMF_5_2_0rp3/src/include/ESMCI_Util.h:25,&#xA;                 from /home/user/esmf-ESMF_5_2_0rp3/src/include/ESMCI_LogErr.h:34,&#xA;                 from /home/user/esmf-ESMF_5_2_0rp3/src/include/ESMCI_Comp.h:33,&#xA;                 from /home/user/esmf-ESMF_5_2_0rp3/src/Superstructure/WebServices/src/../include/ESMCI_WebServNetEsmfServer.h:23,&#xA;                 from /home/user/esmf-ESMF_5_2_0rp3/src/Superstructure/WebServices/src/ESMCI_WebServNetEsmfServer.C:28:&#xA;/usr/include/c++/7/bits/stl_pair.h:448:5: note: candidate: template&amp;lt;class _T1, class _T2&amp;gt; constexpr bool std::operator==(const std::pair&amp;lt;_T1, _T2&amp;gt;&amp;amp;, const std::pair&amp;lt;_T1, _T2&amp;gt;&amp;amp;)&#xA;     operator==(const pair&amp;lt;_T1, _T2&amp;gt;&amp;amp; __x, const pair&amp;lt;_T1, _T2&amp;gt;&amp;amp; __y)&#xA;     ^~~~~~~~&#xA;/usr/include/c++/7/bits/stl_pair.h:448:5: note:   template argument deduction/substitution failed:&#xA;In file included from /usr/include/rpc/netdb.h:42:0,&#xA;                 from /usr/include/netdb.h:32,&#xA;                 from /home/user/esmf-ESMF_5_2_0rp3/src/Superstructure/WebServices/src/ESMCI_WebServNetEsmfServer.C:31:&#xA;/home/user/esmf-ESMF_5_2_0rp3/src/Superstructure/WebServices/src/ESMCI_WebServNetEsmfServer.C:1798:34: note:   ‘std::fstream {aka std::basic_fstream&amp;lt;char&amp;gt;}’ is not derived from ‘const std::pair&amp;lt;_T1, _T2&amp;gt;’&#xA;  if ((fin == NULL)  ||  (fout == NULL))&#xA;                                  ^&#xA;/home/user/esmf-ESMF_5_2_0rp3/build/common.mk:2994: recipe for target '/home/user/esmf-ESMF_5_2_0rp3/obj/objO/Linux.gfortran.64.openmpi.default/ESMCI_WebServNetEsmfServer.o' failed&#xA;make[8]: *** [/home/user/esmf-ESMF_5_2_0rp3/obj/objO/Linux.gfortran.64.openmpi.default/ESMCI_WebServNetEsmfServer.o] Error 1&#xA;make[8]: Leaving directory '/home/user/esmf-ESMF_5_2_0rp3/mod/modO/Linux.gfortran.64.openmpi.default'&#xA;/home/user/esmf-ESMF_5_2_0rp3/build/common.mk:1528: recipe for target 'esmflib' failed&#xA;make[7]: *** [esmflib] Error 2&#xA;make[7]: Leaving directory '/home/user/esmf-ESMF_5_2_0rp3/mod/modO/Linux.gfortran.64.openmpi.default'&#xA;/home/user/esmf-ESMF_5_2_0rp3/build/common.mk:1524: recipe for target 'tree_lib' failed&#xA;make[6]: *** [tree_lib] Error 2&#xA;make[6]: Leaving directory '/home/user/esmf-ESMF_5_2_0rp3/src/Superstructure/WebServices/src'&#xA;/home/user/esmf-ESMF_5_2_0rp3/build/common.mk:2922: recipe for target 'tree' failed&#xA;make[5]: *** [tree] Error 1&#xA;make[5]: Leaving directory '/home/user/esmf-ESMF_5_2_0rp3/src/Superstructure/WebServices'&#xA;/home/user/esmf-ESMF_5_2_0rp3/build/common.mk:2922: recipe for target 'tree' failed&#xA;make[4]: *** [tree] Error 1&#xA;make[4]: Leaving directory '/home/user/esmf-ESMF_5_2_0rp3/src/Superstructure'&#xA;/home/user/esmf-ESMF_5_2_0rp3/build/common.mk:2922: recipe for target 'tree' failed&#xA;make[3]: *** [tree] Error 1&#xA;make[3]: Leaving directory '/home/user/esmf-ESMF_5_2_0rp3/src'&#xA;/home/user/esmf-ESMF_5_2_0rp3/build/common.mk:2922: recipe for target 'tree' failed&#xA;make[2]: *** [tree] Error 1&#xA;make[2]: Leaving directory '/home/user/esmf-ESMF_5_2_0rp3'&#xA;/home/user/esmf-ESMF_5_2_0rp3/build/common.mk:1501: recipe for target 'build_libs' failed&#xA;make[1]: *** [build_libs] Error 2&#xA;make[1]: Leaving directory '/home/user/esmf-ESMF_5_2_0rp3'&#xA;/home/user/esmf-ESMF_5_2_0rp3/build/common.mk:1494: recipe for target 'lib' failed&#xA;make: *** [lib] Error 2&#xA;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Where is my mistake? Am I missing anything in the building procedure? I have also tried to install ESMF using GCC&amp;amp;G++-8.1.0, but the same error came up. If somebody reccomend a solution for this problem it will be a great help. Thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="22108" LastActivityDate="2021-03-26T06:36:34.453" Title="ESMF installation error &quot;error: no match for ‘operator==’ &quot;" Tags="|numerical-modelling|ocean-models|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21017" PostTypeId="1" CreationDate="2021-03-26T07:44:39.223" Score="3" ViewCount="71" Body="&lt;p&gt;How can we tell the difference between a seismograph of a local earthquake and that of a distant earthquake?&lt;/p&gt;&#xA;" OwnerUserId="21934" LastActivityDate="2021-03-26T16:11:26.220" Title="Difference between Earthquake Seismographs" Tags="|earthquakes|seismology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21019" PostTypeId="1" CreationDate="2021-03-26T09:12:17.333" Score="2" ViewCount="42" Body="&lt;p&gt;I'm trying to acquire an understanding of how the difficulty of prospecting for useful ore has increased over historical timescales.&lt;/p&gt;&#xA;&lt;p&gt;Intuitively, I would expect that centuries or millennia ago, you could find deposits, at least of common things like iron and copper, just by walking around looking at rock formations, whereas nowadays those have all been discovered, and to find anything new would take a team of experts carefully analyzing subtle clues from geological maps, perhaps with the aid of exotic instruments like gamma-ray spectrometers.&lt;/p&gt;&#xA;&lt;p&gt;Is this general intuition correct? If so, are there any available numbers, even plausible estimates, for how much the difficulty has increased in quantitative terms? Anything like 'in preindustrial times, the average prospecting effort to find an iron ore deposit was X months; by 1800 it had increased to Y months'?&lt;/p&gt;&#xA;" OwnerUserId="7911" LastActivityDate="2021-03-26T09:12:17.333" Title="Ore prospecting and the low-hanging fruit effect" Tags="|geology|minerals|economic-geology|ore|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21020" PostTypeId="1" CreationDate="2021-03-26T11:59:11.937" Score="3" ViewCount="478" Body="&lt;p&gt;The deepest borehole ever drilled is just 12km.&lt;/p&gt;&#xA;&lt;p&gt;Consider this as a possibility. A small self-propelled probe is created, its approximately the size of a football, and is very strong, made of materials with a melting point of a few thousand K. If this was dropped into one of the planet's various volcanic lava lakes, how far down could it travel? Or does the viscosity of the molten rock increase with depth limiting it to a few 100m only?&lt;/p&gt;&#xA;" OwnerUserId="22110" LastActivityDate="2021-03-31T06:43:35.583" Title="It is possible to send a probe deep within the Earth?" Tags="|volcanology|" AnswerCount="5" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21021" PostTypeId="2" ParentId="21020" CreationDate="2021-03-26T14:24:41.340" Score="1" Body="&lt;p&gt;I'd say it could reach, at the very best, the base of the continental crust (usually around 30 km depth). Even getting there could be tricky: the probe would have to travel what we call the &amp;quot;plumbing system&amp;quot; of the volcano, made of interconnected &lt;a href=&quot;https://en.wikipedia.org/wiki/Dike_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;dykes&lt;/a&gt; (which can be quite narrow: only a few centimeters in some cases) and reservoirs, where convection and crystal mush would make its life hard... But assuming the probe would find its way through this maze, it would eventually reach a big magma chamber under the continental crust. Getting deeper would require drilling: the mantle is solid but not brittle, so it does not fracture to let magma ascend (like with dykes). Instead, it is generally considered that magma migrates through the mantle using grain boundaries, i.e., the small spaces between crystals of the mantle rock (peridotite). These are way too small for any probe to travel through.&lt;/p&gt;&#xA;&lt;p&gt;On another note, you mentioned materials with a high melting point, but you'd also need something able to resist very high pressures... And finally, how would you get the data back? I can't imagine a way for the probe to transmit data back to the surface, so even if it managed to get down there, you won't know its findings...&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2021-03-26T14:24:41.340" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21022" PostTypeId="2" ParentId="21020" CreationDate="2021-03-26T15:18:11.290" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Consider this as a possibility. &lt;strong&gt;A small self-propelled probe is created, its approximately the size of a football, and is very strong, made of materials with a melting point of a few thousand K. If this was dropped into one of the planet's various volcanic lava lakes, how far down could it travel? Or does the viscosity of the molten&lt;/strong&gt; rock increase with a depth limiting it to a few 100m only?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;em&gt;This question could be answered on Worldbuilding SE, I'm just going to answer the part where the user asks how far it could travel and the materials that could possibly survive the probing mission.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;First off I will start with listing Materials with high-melting points.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;h2&gt;Tantalum Hafnium Carbide Alloy (3990℃)&lt;/h2&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Tantalum hafnium carbide alloy takes the 1st place in our list of the materials with the highest melting point.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Tantalum hafnium carbide alloy (Ta4HfC5) actually refers to tantalum and hafnium pentacarbonate compound, which has the highest melting point among known compounds. It can be considered to be composed of two binary compounds, tantalum carbide (melting point 3983 ℃) and hafnium carbide (melting point 3928℃).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Tantalum hafnium carbide alloys are &lt;strong&gt;used as heat resistant and high strength materials for rocket and jet engines, as well as parts for control and adjustment equipment.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.refractorymetal.org/list-of-metals-that-can-withstand-high-temperatures/&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Source&lt;/em&gt;&lt;/a&gt;. The article listed that tantalum Hafnium carbon alloy, &amp;quot;used as heat resistant and high strength materials for rocket and jet engines, as well as parts for control and adjustment equipment.&amp;quot; So you could incorporate this material into you're probe&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;h2&gt;2. Graphite (3652 ℃)&lt;/h2&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Graphite ranks 2nd in our list of the materials with the highest melting point in the world.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Graphite is an allotrope of carbon, where three other carbon atoms (arranged in a honeycomb of hexagons) are covalently linked to each other to form covalent molecules. Due to its special structure, it has high-temperature resistance, electrical and thermal conductivity, lubricity, chemical stability, plasticity and so on.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Traditional graphite can be used as a refractory material, the &lt;strong&gt;conductive material, wear-resistant, and lubricating material casting,&lt;/strong&gt; sand, die and high-temperature metallurgy material, while new graphite used as &lt;strong&gt;flexible graphite sealing material,&lt;/strong&gt; &lt;strong&gt;car battery, new composite material, etc.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Graphite has a high melting point and can be used for many purposes, I recommend incorporating this into your probe.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;h2&gt;3. Diamond (3550 ℃)&lt;/h2&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Diamond is another material that has very high melting points. Diamond is atomic crystal, while graphite is mixed crystal. The melting point of graphite crystal is higher than that of the diamond, which seems incredible.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;However, the bond length of covalent bonds in the flake layer of graphite crystal is 1.42×10-10m, and the bond length of covalent bonds in the diamond crystal is 1.55×10-10m. Covalent bonds, the smaller the bond, the bigger the bond energy, the stronger the bond, the harder it is to break, the more energy you have to provide, so the melting point should be higher.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Diamond is used for cutting tools in arts and crafts and industry, such as drawing die, turning tool, thread cutter, durometer head, geological and petroleum drill bit, grinding wheel cutter, glass cutter, diamond pen, dresser knife, and abrasive material.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Although Diamonds have high melting points, they have limited purposes. I recommend using this to build your probe or using it as a shield for your probe.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;I listed the top three in the article list. If you want to see more of the top ten check out this link: &lt;a href=&quot;https://www.refractorymetal.org/list-of-metals-that-can-withstand-high-temperatures/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.refractorymetal.org/list-of-metals-that-can-withstand-high-temperatures/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;h1&gt;How to put your probe in the earth&lt;/h1&gt;&#xA;&lt;p&gt;Say, you have at least the top 3 or top 2 materials with the high melting points, you use expensive and futuristic technology and you have much research funding, but there is 1 thing in our way: How to put the probe into the earth.&lt;/p&gt;&#xA;&lt;h3&gt;&lt;em&gt;The text you are about to read is based almost entirely on my observations&lt;/em&gt;&lt;/h3&gt;&#xA;&lt;p&gt;If your probe is the size of the football (Like you noted in your question), then I recommend digging a huge hole in a dormant or not-to-active volcanic geography after you do this (Do it extremely close to a dormant volcano, wearing a volcano suit), get a huge and long metal bar. hit the bar on the bottom of the hole. If you find extremely hot rock or magma/lava try a few more hits to molten or weak it further.&lt;/p&gt;&#xA;&lt;p&gt;Once it's at the point of smoke or steam going out of the hole you made, I suggest using a non-electrical powered long shovel to dig further to make sure there is a lava flow &amp;quot;pipe&amp;quot; running in the crust, either carefully push ur probe under the lava once the lava is sinking back into the hole or simply throw your probe in a dormant volcano.&lt;/p&gt;&#xA;&lt;p&gt;It's best the probe is scripted and computed to stay in the upper-middle mantle (For Data and safe exploration for your probe)&lt;/p&gt;&#xA;" OwnerUserId="21926" LastActivityDate="2021-03-26T15:18:11.290" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="21023" PostTypeId="2" ParentId="21017" CreationDate="2021-03-26T16:11:26.220" Score="3" Body="&lt;p&gt;An earthquake generates waves that move through the earth in different ways. Two of the principle waves are the compressional P wave and the shear S wave.  P waves move faster than S waves, so by timing the difference in arrival time of the two waveforms we can estimate the distance to the epicentre.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/C3DCe.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/C3DCe.png&quot; alt=&quot;A seismograph showing the interval between P and S waves&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.bgs.ac.uk/discovering-geology/earth-hazards/earthquakes/how-are-earthquakes-detected/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.bgs.ac.uk/discovering-geology/earth-hazards/earthquakes/how-are-earthquakes-detected/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2021-03-26T16:11:26.220" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21024" PostTypeId="1" CreationDate="2021-03-27T15:49:41.087" Score="4" ViewCount="75" Body="&lt;p&gt;I have a number of arrays describing both forecasts and observations of geospatial data (e.g. precipitation intensity, cloud fields...). Included are four animated gifs, each looping back and forth between an observation (of precipitation) &amp;amp; a forecast covering the period of the observation. The four forecasts vary markedly in quality (from extremely good in the first case to terrible in the fourth).&lt;/p&gt;&#xA;&lt;p&gt;I would like to have some way of systematically quantifying the similarity between two such arrays (e.g. between an observation and its associated forecast). I don't really know any more sophisticated way than to simply take the difference between two arrays (normalized somehow, e.g. by dividing by the mean of one of the first).&lt;/p&gt;&#xA;&lt;p&gt;The problem is that 'scoring' the forecasts in this way gives case #3 &amp;amp; #4 equally bad marks - even though from visual inspection case #3 appears substantially better than #4. Clouds which are in slightly the wrong place (e.g. the ones in central Germany, or in Switzerland &amp;amp; Western Austria, in case #3) score equally poorly to those which are in &lt;em&gt;entirely&lt;/em&gt; the wrong place, or simply absent.&lt;/p&gt;&#xA;&lt;p&gt;Ideally, I'd like some measure of the minimum amount by which one image needs to be 'deformed' to yield another one, but I have no idea how to approach that in anything like a systematic manner.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CHRwP.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CHRwP.gif&quot; alt=&quot;An animated gif comparing observed precipitation to a forecast covering the same period&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/WFQzZ.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WFQzZ.gif&quot; alt=&quot;n animated gif comparing observed precipitation to a forecast covering the same period&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/IYl5d.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IYl5d.gif&quot; alt=&quot;n animated gif comparing observed precipitation to a forecast covering the same period&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ImPx6.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ImPx6.gif&quot; alt=&quot;n animated gif comparing observed precipitation to a forecast covering the same period&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22116" LastActivityDate="2021-03-30T17:49:26.357" Title="Comparing 2D fields - how do you quantify similarity?" Tags="|data-analysis|weatherdata|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21025" PostTypeId="1" CreationDate="2021-03-27T16:46:54.490" Score="2" ViewCount="594" Body="&lt;p&gt;I am trying to understand the actual meaning of the &lt;a href=&quot;https://www.ecmwf.int/en/forecasts/documentation-and-support/137-model-levels&quot; rel=&quot;nofollow noreferrer&quot;&gt;ECMWF L137 model levels&lt;/a&gt;. In the link I provided, both pressures (in hPa) and heights (in m)  are given for every level. But which actually &lt;em&gt;defines&lt;/em&gt; the model level, and which is merely included as an indicative value?&lt;/p&gt;&#xA;" OwnerUserId="22116" LastActivityDate="2021-03-28T05:14:22.663" Title="Meaning of ECMWF model levels" Tags="|atmosphere-modelling|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21026" PostTypeId="1" CreationDate="2021-03-27T17:09:57.193" Score="3" ViewCount="90" Body="&lt;p&gt;Some types of used plastics are very stable.&lt;br /&gt;&#xA;They also contain a significant amount of carbon.&lt;br /&gt;&#xA;An example is polyethylene (PE).&lt;/p&gt;&#xA;&lt;p&gt;When waste is collected for recycling, not every plastic part can be reused. There is a fraction that is usually burned, creating CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&lt;p&gt;We want to avoid accumulating CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere, and look for methods to store carbon under ground.&lt;/p&gt;&#xA;&lt;p&gt;Why don't we store used plastics under ground, in a long term stable way?&lt;/p&gt;&#xA;&lt;p&gt;I am not sure how normal mixed waste dumps behave in the long term, but they have drawbacks. For example they can leak substances from the other parts of the mixed waste and they can burn.&lt;/p&gt;&#xA;&lt;p&gt;But other methods seem stable to me: Solid PE blocks of standard pallet size, stacked underground in abandoned mines should be long term stable, I think. But it is not about the specific place of storage, a mine is only an illustration to argue that it is possible.&lt;/p&gt;&#xA;" OwnerUserId="321" LastEditorUserId="321" LastEditDate="2021-03-28T16:59:36.863" LastActivityDate="2021-03-28T16:59:36.863" Title="Why don't we store carbon by storing used plastics under ground?" Tags="|co2|carbon|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21027" PostTypeId="2" ParentId="21025" CreationDate="2021-03-27T20:47:30.517" Score="2" Body="&lt;p&gt;Since it discusses the pressure values setup first, then says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Also &lt;em&gt;&lt;strong&gt;provided&lt;/strong&gt;&lt;/em&gt; are the Geopotential and Geometric heights, the&#xA;temperature and density of the level &lt;strong&gt;based on&lt;/strong&gt; the 1976 version of the&#xA;International Civil Aviation Organization (ICAO) Standard Atmosphere...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I would take that to indicate that the vertical coordinates are defined by pressure, which is how I've always believed it to be.  And then the other values are just estimates from the standard atmosphere approximation.&lt;/p&gt;&#xA;&lt;p&gt;In addition &lt;a href=&quot;https://rda.ucar.edu/datasets/ds115.4/docs/levels.hybrid.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://rda.ucar.edu/datasets/ds115.4/docs/levels.hybrid.html&lt;/a&gt; looks to give more details on the vertical setup...&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The vertical coordinate parameters &lt;strong&gt;define&lt;/strong&gt; the edges of the atmospheric&#xA;layers &lt;strong&gt;in terms of the surface pressure&lt;/strong&gt; (in Pascals). The parameters&#xA;can be considered as being true at the mid-point (in pressure) of a&#xA;layer for each point. The formula to use to determine edges of the&#xA;layers is &lt;span class=&quot;math-container&quot;&gt;$P_{k+1/2} = A_{k+1/2} + B_{k+1/2}P_s$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$P_s$&lt;/span&gt; is the surface pressure and &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$B$&lt;/span&gt; are defined in the table.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So others who work on modeling may be able to offer further input on the setup, but from my casual understanding, it looks to definitely be based on pressure :-)&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2021-03-28T05:14:22.663" LastActivityDate="2021-03-28T05:14:22.663" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21028" PostTypeId="1" CreationDate="2021-03-27T22:25:18.260" Score="5" ViewCount="96" Body="&lt;p&gt;According to Mann and Kump (2015),&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Geologic proxies are characteristics of sedimentary rocks that we can&#xA;use to infer ancient environmental conditions. Climate scientists&#xA;study proxies because there are no thermometer records or samples of&#xA;ancient air from the geologic past. Proxies may even include the pores&#xA;on fossil leaves: when atmospheric CO&lt;sub&gt;2&lt;/sub&gt; levels are low, plants need&#xA;more pores to bring in more CO&lt;sub&gt;2&lt;/sub&gt;. Under the microscope, well-preserved&#xA;fossils reveal the number of pores; comparing this pore density to&#xA;that of living plants allows scientists to establish CO&lt;sub&gt;2&lt;/sub&gt; levels in the&#xA;geologic past.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;However, in order to use this comparison to make inferences about CO&lt;sub&gt;2&lt;/sub&gt; levels, it seems to me that this would require establishing that everything else is held equal. If this is not established, it seems to me that this would not allow one to use plant pores as proxies for past CO&lt;sub&gt;2&lt;/sub&gt; levels and thus climate change. Therefore, my question is, how do researchers attempt to hold all else equal when comparing the pore density of fossilized plants to living plants to establish a causal relation between past CO&lt;sub&gt;2&lt;/sub&gt; levels and plant pores density?&lt;/p&gt;&#xA;&lt;p&gt;Reference:&lt;/p&gt;&#xA;&lt;p&gt;Mann, M. E. and L. R. Kump (2015). Dire Predictions: Understanding Climate Change 2nd Edition. DK Publishing.&lt;/p&gt;&#xA;" OwnerUserId="22117" LastEditorDisplayName="user20559" LastEditDate="2021-10-31T19:13:14.240" LastActivityDate="2021-10-31T19:13:14.240" Title="How is causality between past CO$_2$ levels and fossilized plant pores proxies established?" Tags="|climate-change|co2|plant|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21029" PostTypeId="2" ParentId="21026" CreationDate="2021-03-28T02:24:38.447" Score="1" Body="&lt;p&gt;Some locations don't have the available space to dump rubbish underground and those that do are running out of suitable dump locations.&lt;/p&gt;&#xA;&lt;p&gt;Similarly, the location of abandoned mines and the available dumping space is also limited. Prior to using abandoned mines, many will need to be made safe by implementing ground control measures to prevent injuring from falling rock and to prevent cave in.&lt;/p&gt;&#xA;&lt;p&gt;Some mines, particularly coal mines have been mined to subside shortly after coal has been removed, making such mines unusable.&lt;/p&gt;&#xA;&lt;p&gt;Some mines were constructed underneath the water table and are now flooded. Such mines would need to be de-watered and made safe. The water would need to be dumped somewhere, which and may need to be treated prior to dumping because of metals that may have leached into the water from minerals in the abandoned mine.&lt;/p&gt;&#xA;&lt;p&gt;Once such mines have been backfilled the ground water will again flood the mine. The question of how any plastics would behave when submerged needs to be investigated to mitigate against deleterious environmental effects.&lt;/p&gt;&#xA;&lt;p&gt;Some old mines were established using manual methods and have short height and narrow width tunnels which would require a lot of manual handling to make the mines safe and to dump plastics in them. Alternatively, the tunnels may need to be enlarged to allow the used of heavy machinery in dumping the plastics. This would be expensive and may not be practical in some cases.&lt;/p&gt;&#xA;&lt;p&gt;The location of some mines is far from population centers which would required expensive haulage to the mines.&lt;/p&gt;&#xA;&lt;p&gt;It would be to reuse plastics in another way, if possible, or to stop using them or significantly reduce their usage.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-03-28T02:24:38.447" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21030" PostTypeId="2" ParentId="21024" CreationDate="2021-03-28T11:55:28.137" Score="0" Body="&lt;p&gt;You are looking to do some sort of &lt;a href=&quot;https://en.wikipedia.org/wiki/Regression_validation&quot; rel=&quot;nofollow noreferrer&quot;&gt;regression analysis&lt;/a&gt; on two-dimensional data. The &lt;span class=&quot;math-container&quot;&gt;$r^2$&lt;/span&gt; &lt;a href=&quot;https://en.wikipedia.org/wiki/Coefficient_of_determination&quot; rel=&quot;nofollow noreferrer&quot;&gt;coefficient of determination&lt;/a&gt; value is often used for one dimensional data. &lt;span class=&quot;math-container&quot;&gt;$r^2=1$&lt;/span&gt; means a perfect match and &lt;span class=&quot;math-container&quot;&gt;$r^2=0$&lt;/span&gt; means no correlation. &lt;span class=&quot;math-container&quot;&gt;$r^2$&lt;/span&gt; may be used for two-dimensional data as well; I don't know. Another example is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Kolmogorov%E2%80%93Smirnov_test&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kolmogorov–Smirnov test&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Neither of these are, unfortunately, something I know much about but hopefully this will point you in the right direction. What I do know is that this sort of analysis is regularly used for just this situation to assess model output.&lt;/p&gt;&#xA;&lt;p&gt;I found a &lt;a href=&quot;https://aip.scitation.org/doi/pdf/10.1063/1.4822753&quot; rel=&quot;nofollow noreferrer&quot;&gt;1988 scientific paper&lt;/a&gt; by William H. Press and Saul A. Teukolsky entitled &lt;em&gt;Kolmogorov-Smirnov Test For Two-Dimensional Data: How to tell whether a set of (x,y) data points are consistent with a particular probability distribution, or with another data set&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;The paper gives a Numerical Method, basically an algorithm, to apply this to your data. It's not in a modern programming language but you should be able to write the equivalent based on what is described. The &lt;code&gt;R&lt;/code&gt; programming language may even come with an inbuilt solution.&lt;/p&gt;&#xA;&lt;p&gt;The answer in that paper should do what you want but whether it is the &lt;em&gt;best&lt;/em&gt; way of doing it, I have no idea.&lt;/p&gt;&#xA;" OwnerUserId="20542" LastEditorUserId="20542" LastEditDate="2021-03-30T17:49:26.357" LastActivityDate="2021-03-30T17:49:26.357" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21031" PostTypeId="2" ParentId="3122" CreationDate="2021-03-28T22:02:43.183" Score="2" Body="&lt;p&gt;Quite a few cities were built overtop of ore deposits. They often started out as a series of small workings and larger, deeper deposits were found as the cities grew up to support the mining.&lt;/p&gt;&#xA;&lt;p&gt;An example is Bendigo Australia where there were mines under the centre of town&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1WKII.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1WKII.png&quot; alt=&quot;&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.bendigoadvertiser.com.au/story/3863770/mining-set-to-resume-in-bendigo/#slide=3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mining has continued off and on with the most recent activity using a decline for trucks to reach the the ore at a depth of ~ 1km&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KHaR0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KHaR0.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1242" LastActivityDate="2021-03-28T22:02:43.183" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21032" PostTypeId="2" ParentId="20993" CreationDate="2021-03-29T01:20:14.107" Score="5" Body="&lt;p&gt;The answer is maybe -- if you are looking deep in the mantle rather than in the core, and if you are prepared to accept &amp;quot;superionic&amp;quot; ice in which the molecular structure of water has broken down and instead, you have mobile protons embedded in an oxide-ion lattice.  In the core itself the water reacts with the hot iron under pressure, actually forming a metal hydride.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Fire and ice&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Deep inside the Earth, where pressures reach GPa levels and temperatures exceed 2000 K, water may exist in two forms, neither of which is anything like the material we are familiar with at the surface.  One of these is a supercritical fluid in which the temperature and pressure are not only too high to allow vapor-liquid equilibrium, but also high enough to turn the protons into highly mobile species in this fluid, which is therefore chock full of ionic species.  The second of these forms is a &amp;quot;solid&amp;quot; in the sense that it contains a rigid lattice of oxide ions, but the hydrogen ions move among them as if they were still liquid.  This is the long-sought and now (since 2019) verified &lt;a href=&quot;https://en.wikipedia.org/wiki/Superionic_water&quot; rel=&quot;nofollow noreferrer&quot;&gt;superionic ice&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The University of Arizona [&lt;a href=&quot;https://www.geo.arizona.edu/xtal/geos306/geos306-13.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;] shows a calculated temperature-pressure relation as one proceeds deep into the Earth, given in the figure below.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/f2OGL.gif&quot; alt=&quot;enter image description here&quot; /&gt;&#xA;From Ref. [1].&lt;/p&gt;&#xA;&lt;p&gt;The sharp rise in temperature in the middle of the chart corresponds to the boundary between the mantle and the core.  We see that just short of this boundary the pressure is about 100 GPa and the temperature about 3000 K.&lt;/p&gt;&#xA;&lt;p&gt;Under these conditions, some calculations such as that from Millot et al. [&lt;a href=&quot;https://www.researchgate.net/publication/332961479_Nanosecond_X-ray_diffraction_of_shock-compressed_superionic_water_ice&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;] indicates that the water may turn into the superionic ice state at this boundary.  In the figure below, the point at 100 GPa and 3000 K lies in the white border region where, according to the authors' calculations, the water may be an ionic supercritical fluid or superionic ice.  At lower depths, however, the temperature and pressure are more firmly in the green ionic fluid range.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/MI8F3.png&quot; alt=&quot;enter image description here&quot; /&gt;&#xA;From Ref. [2].  &lt;a href=&quot;https://www.researchgate.net/figure/Phase-diagram-of-H2O-Pressure-temperature-conditions-of-the-XRD-measurements-in-the_fig4_332961479&quot; rel=&quot;nofollow noreferrer&quot;&gt;Figure link&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;And then there was none&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Water vapor is well known to react with iron and steel in industrial processes, forming iron oxide and hydrogen (we usually limit the water vapor content and add hydrogen to the atmosphere to halt this reaction).  Such a reaction also occurs under the high pressure and temperature of the core [&lt;a href=&quot;https://academic.oup.com/nsr/article/4/6/870/4107791&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;], although it takes a different course.  Instead of evolving as gas, the hydrogen from the water forms a layer of iron hydride, a material which, as a pure compound, is unstable under normal conditions.  This acts as a source of hydrogen that may reduce material in the overlying mantle.  See the figure below.&lt;/p&gt;&#xA;&lt;p&gt;From Ref. [3].  &lt;a href=&quot;https://www.researchgate.net/figure/Schematic-diagram-of-ORP-in-the-DLM-Hydrous-minerals-in-the-subducting-slab-blue-carry_fig3_321123868&quot; rel=&quot;nofollow noreferrer&quot;&gt;Figure source&lt;/a&gt;&lt;img src=&quot;https://i.stack.imgur.com/HmU2w.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;1.&#xA;Educational material from the University of Arizona.&lt;/p&gt;&#xA;&lt;p&gt;2.&#xA;Marius Millot, Federica Coppari, J. Ryan Rygg, Antonio Correa Barrios, Sebastien Hamel, Damian C Swift, J. H. Eggert, &amp;quot;Nanosecond X-ray diffraction of shock-compressed superionic water ice&amp;quot;, &lt;em&gt;Nature&lt;/em&gt; &lt;strong&gt;569&lt;/strong&gt;(7755):251-255 (May 2019).&#xA;DOI: 10.1038/s41586-019-1114-6&lt;/p&gt;&#xA;&lt;p&gt;3.&#xA;Ho-Kwang Mao, Qingyang Hu, Liuxiang Yang, Jin Liu, Duck Young Kim, Yuanku Meng, Li Zhang, Vitali B. Prakapenka, Wenge Yang, Wendy L. Mao, &amp;quot;When water meets iron at Earth's core mantle boundary&amp;quot;, National Science Review &lt;strong&gt;4&lt;/strong&gt;(6), 109 (Sept. 2017).&#xA;DOI: 10.1093/nsr/nwx109&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2021-03-29T19:21:57.057" LastActivityDate="2021-03-29T19:21:57.057" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21033" PostTypeId="1" CreationDate="2021-03-29T03:38:18.060" Score="3" ViewCount="161" Body="&lt;p&gt;About the Caspian sea area today:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The south is very lush with the subtropical forests of the Iranian provinces of &lt;a href=&quot;https://en.wikipedia.org/wiki/Northern_Iran&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gilan, Mazandaran and Golestan&lt;/a&gt; (although less &amp;quot;tropical&amp;quot; in Golestan)&lt;/li&gt;&#xA;&lt;li&gt;The west tends to be lush with subtropical (?) thicket and also forests around &lt;a href=&quot;https://en.wikipedia.org/wiki/Baku&quot; rel=&quot;nofollow noreferrer&quot;&gt;Baku&lt;/a&gt; and lots of thicket at least up to &lt;a href=&quot;https://en.wikipedia.org/wiki/Derbent&quot; rel=&quot;nofollow noreferrer&quot;&gt;Derbent&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;The north is pretty much part of the Euroasian Steppe but might not have been until the rise of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Khazars&quot; rel=&quot;nofollow noreferrer&quot;&gt;Khazar empire&lt;/a&gt; or earlier --- &lt;a href=&quot;https://en.wikipedia.org/wiki/Scythians&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scythian empire&lt;/a&gt; in the region which might have caused significant deforestation although still has some rich thicket/grove areas left today&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;And yet, the eastern coast of the Caspian sea seemed to me from almost any image as a dry &amp;quot;wasteland&amp;quot;, with almost no thicket and certainly nothing I would name &amp;quot;a forest&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Why are the south, the west and the north of the Caspian sea lush but its east completely dry?&lt;/p&gt;&#xA;" OwnerUserId="22128" LastEditorUserId="22128" LastEditDate="2021-03-29T12:32:59.233" LastActivityDate="2021-03-29T16:26:02.023" Title="Why are the south, the west and the north of the Caspian sea lush but its east completely dry?" Tags="|earth-history|sea-level|topography|deforestation|desertification|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21034" PostTypeId="1" CreationDate="2021-03-29T11:03:21.577" Score="4" ViewCount="607" Body="&lt;p&gt;Does a stream require a certain width or volume before it can be classified as a river, and if so, what is it?&lt;/p&gt;&#xA;" OwnerUserId="21871" LastActivityDate="2021-03-30T01:13:59.007" Title="When does a stream become a river?" Tags="|rivers|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21035" PostTypeId="2" ParentId="21033" CreationDate="2021-03-29T16:10:08.080" Score="3" Body="&lt;p&gt;The mountains.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ICmkRl.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ICmkRl.png&quot; alt=&quot;Caspian see&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The south has a steep relief, as well as the west. That means that there is much precipitation. The clouds throw every drop on these mountains, so almost nothing is left. The east is pretty low, so the remaining clouds (not much left) just fly over. In fact, deserts are generally not steep and they are usually behind the mountains. That is right what happens here. On the north, the effects of the west are still felt, so it isn't so dry, but it is pretty low, too. Also, I wouldn't say that it's lush : )&lt;/p&gt;&#xA;" OwnerUserId="19122" LastEditorUserId="19122" LastEditDate="2021-03-29T16:26:02.023" LastActivityDate="2021-03-29T16:26:02.023" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21036" PostTypeId="1" AcceptedAnswerId="21044" CreationDate="2021-03-29T19:51:28.193" Score="6" ViewCount="2070" Body="&lt;p&gt;The Persian Gulf, today, looks like this.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IZQf6.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IZQf6.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But about 4,000 years ago, it looked like this.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pb4rZ.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pb4rZ.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This extended to the point where Ur, currently an inland city, was a coastal city. During this era, no other coastlines that I am aware of have had such a dramatic change. The research I've done has not yielded many results. I do believe that a while ago, I read something saying a flood of the Tigris and Euphrates rivers deposited sediment lower down. I was unable to find this again.&lt;/p&gt;&#xA;&lt;p&gt;So my question is, what were the cause(s) of the change of coastline?&lt;/p&gt;&#xA;" OwnerUserId="21997" LastEditorUserId="21997" LastEditDate="2021-03-29T20:22:27.037" LastActivityDate="2021-04-01T07:09:14.593" Title="Why did the Persian Gulf shrink during the influence of Ancient Mesopotamia?" Tags="|coastal|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21037" PostTypeId="2" ParentId="21020" CreationDate="2021-03-30T00:06:54.440" Score="7" Body="&lt;p&gt;First, read these three very relevant questions and answers:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/16730/725&quot;&gt;Why the &amp;quot;Mission to Earth’s core&amp;quot; proposal suggests using liquid iron instead of lead?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/246/725&quot;&gt;Can we really travel through earth&amp;#39;s core?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/2468/725&quot;&gt;Hypothetically, what would happen to the earth if a large hole was drilled through the center?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;It is possible to send a probe deep within the Earth?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;h1&gt;No.&lt;/h1&gt;&#xA;&lt;h2&gt;Here's why:&lt;/h2&gt;&#xA;&lt;p&gt;First, there is a very common misconception that there's some sort of magma ocean underneath the crust. No - there isn't. The Earth's mantle is overwhelmingly solid rock. There are very small and localised places where you have melting, and that's where you have volcanoes (if it reaches the surface - most often it doesn't).&lt;/p&gt;&#xA;&lt;p&gt;Second, even if you go to a volcano and drop your probe there, there is no simple tube that goes down. A volcano &amp;quot;plumbing&amp;quot; system is more like a maze with bifurcations, bends, kinks, and all of that. Not only that, you are going against the flow. You've probably seen videos of erupting lava flows (&lt;a href=&quot;https://youtu.be/scDy7gt4YEo&quot; rel=&quot;noreferrer&quot;&gt;one&lt;/a&gt;, &lt;a href=&quot;https://youtu.be/L4qDgsyFw7M&quot; rel=&quot;noreferrer&quot;&gt;two&lt;/a&gt;). These things are massive and fast. Your probe will have to go against the flow in that thing. It will be worse than trying to go upstream in &lt;a href=&quot;https://youtu.be/DXFehwLKO6I&quot; rel=&quot;noreferrer&quot;&gt;river rapids&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Third, even if you somehow manage to make a probe that autonomously navigates upstream in thin underground lava corridors with surprise bends, you have to remember the underground magma chambers are not 100% liquid. They are what we call &amp;quot;crystal mushes&amp;quot;, which is a pile of small crystals (i.e., bits of rock) with liquid in between. Think more like wet sand, than pure liquid. So you're not swimming in something with no resistance, you also actively have more solids out of your way.&lt;/p&gt;&#xA;&lt;p&gt;Fourth, molten rocks are &lt;strong&gt;extremely&lt;/strong&gt; corrosive. You were talking about materials with high melting points. That's not your problem. Even the hottest lavas only get to about 1400 °C. We have relatively cheap materials that will melt at much higher temperatures. The issue is the reaction between the magma and the materials into making new materials, or dissolving completely in the magma. As an illustration, consider sodium chloride. Salt. The point at which it &lt;a href=&quot;https://www.youtube.com/results?search_query=melting%20sodium%20chloride&quot; rel=&quot;noreferrer&quot;&gt;melts&lt;/a&gt;, if you stick it into a furnace is around 800 °C. Surely, that's much above the temperature of let's say an ocean, and it might be a good idea to make submarines out of salt! Clearly, bad idea. Because the salt will just dissolve into the ocean. Whether it melts or not is irrelevant. So that's the big problem with your probes - the magma will simply dissolve it.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;So to sum up, you need your probe to be able to navigate in the dark and propel itself upstream in magma, be able to dig and clear space up front so it can move forward, and made of a material which is inert to the magma. Sorry - not happening. But a fun thought experiment nonetheless.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2021-03-30T10:46:22.273" LastActivityDate="2021-03-30T10:46:22.273" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="21038" PostTypeId="2" ParentId="21034" CreationDate="2021-03-30T01:13:59.007" Score="2" Body="&lt;p&gt;There's no official distinction between a river and a creek, both of which are categories of streams. As an example, consider &lt;a href=&quot;https://en.wikipedia.org/wiki/Pine_Creek_(Pennsylvania)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pine Creek in Pennsylvania&lt;/a&gt; and &lt;a href=&quot;https://us.geoview.info/po_river,37946879w&quot; rel=&quot;nofollow noreferrer&quot;&gt;Po River in Spotsylvania County, Virginia&lt;/a&gt;. Pine Creek is 87.2 miles long and has a flow rate that ranges between &lt;a href=&quot;https://waterdata.usgs.gov/monitoring-location/01549700/#parameterCode=00060&amp;amp;period=P3650D&quot; rel=&quot;nofollow noreferrer&quot;&gt;40 to 30000 cubic feet per second&lt;/a&gt;. Po River on the other hand is 1.9 miles long and has a row rate that ranges between &lt;a href=&quot;https://waterdata.usgs.gov/monitoring-location/01673800/#parameterCode=00060&amp;amp;period=P3650D&quot; rel=&quot;nofollow noreferrer&quot;&gt;less than 2 to 4000 cubic feet per second&lt;/a&gt;. The longer and larger one is called a creek while the shorter and smaller one is called a river.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2021-03-30T01:13:59.007" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21039" PostTypeId="1" CreationDate="2021-03-30T11:12:40.233" Score="5" ViewCount="66" Body="&lt;p&gt;Could &lt;a href=&quot;https://en.wikipedia.org/wiki/Gas_hydrate_pingo&quot; rel=&quot;nofollow noreferrer&quot;&gt;gas hydrate pingos&lt;/a&gt; erupt? If so, how quickly? And how much CH&lt;sub&gt;4&lt;/sub&gt; could they release?&lt;/p&gt;&#xA;&lt;p&gt;I'm sorry if the questions sounds silly. I'm new here and I don't know much about gas hydrates and oceanography. I made a few questions earlier this month but I didn't know much about how this site works and I couldn't specify my questions. &lt;a href=&quot;https://cage.uit.no/frontpage/news-archive&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; is where I got the information about the pingos.&lt;/p&gt;&#xA;&lt;p&gt;I just don't know how quickly (or if) they could erupt. This worries me because I don't know much about the subject and the media being alarmist about it doesn't help.&lt;/p&gt;&#xA;" OwnerUserId="22045" LastEditorUserId="2470" LastEditDate="2021-04-01T07:15:12.170" LastActivityDate="2021-04-01T07:15:12.170" Title="Hypothetically, in the near future, could gas hydrate pingos erupt?" Tags="|geology|geophysics|oceanography|glaciology|methane|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="21040" PostTypeId="2" ParentId="21024" CreationDate="2021-03-30T17:44:54.520" Score="2" Body="&lt;p&gt;Model data seta can vary in several ways from a reference data set. Taylor diagrams visually compare multiple datasets output to a reference dataset (e.g., model experiments to observations). This is done by exploiting the geometric relationship between centered RMS, correlation, and standard deviation when computing differences between datasets. Several software packages exist to produce Taylor diagrams.&lt;/p&gt;&#xA;&lt;p&gt;wiki: &lt;a href=&quot;https://en.wikipedia.org/wiki/Taylor_diagram&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Taylor_diagram&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;publication: &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2000JD900719&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2000JD900719&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;python, e.g.: &lt;a href=&quot;https://pypi.org/project/SkillMetrics/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://pypi.org/project/SkillMetrics/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11269" LastActivityDate="2021-03-30T17:44:54.520" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21041" PostTypeId="2" ParentId="21020" CreationDate="2021-03-31T01:20:14.633" Score="0" Body="&lt;p&gt;For power, it would need about 50 times the power output of a space satellite. You'd need &amp;gt;1000w to drill a football sized object through bread-dough consistency rock faster than the flow rate. It requires a currently non existent energy source.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2021-03-31T06:43:35.583" LastActivityDate="2021-03-31T06:43:35.583" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21042" PostTypeId="2" ParentId="21020" CreationDate="2021-03-31T02:05:54.533" Score="0" Body="&lt;p&gt;Temperature and pressure get worse as you get deeper and there's Very few materials that can withstand BOTH.&#xA;Another thing is as you go deeper rock behaves like plastic rather than solid, even if you drill a hole, it'll quickly heal much like poking your finger into some foam. Consecutive drilling would require a sleeve of some sort of material that can withstand immense pressure tha would crush it. At 1 kilometer, pressures of 1100 psi are common, as are temps above 50-60 degrees Celsius. Geostatic Pressure is the stress exerted by the overlying rock or mass above a depth or formation of interest. It is usually at about 1.0 psi per feet although the value can vary depending on the specific area. At 2 kilometers deep, you're already at the Crushing forces beyond even deep sea submersibles.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-03-31T02:05:54.533" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21044" PostTypeId="2" ParentId="21036" CreationDate="2021-03-31T11:28:47.347" Score="5" Body="&lt;p&gt;There has been lots of works trying to reconstruct the evolution of the Gulf shoreline through time. They do not agree on the exact same dates (see this review by &lt;a href=&quot;https://www.researchgate.net/publication/340066759_Sea_Level_Changes_in_the_Mesopotamian_Plain_and_Limits_of_the_Arabian_Gulf_A_Critical_Review&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sissakian et al. 2020&lt;/a&gt;), but they generally agree that there was first a transgression (sea level rise) episode following the last ice age, then a regression (sea level drop). Reasons invoked to explain the regression are (not mutually exclusive):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Change in climate&lt;/strong&gt;. The sea level peaked around the post-glacial climatic optimum. After that, the climate got cooler, which means more ice at the poles and less water in the seas.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Sediment filling&lt;/strong&gt; of the Mesopotamian delta. The Euphrates and the Tigris carry a lot a sediments, which progressively accumulate in the lowlands, making the Gulf shoreline advance (seaward).&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Neotectonics&lt;/strong&gt;. There are evidence for anticline growth under the area, which could have contributed to its rise above sea level. This activity also changed river paths, which could have promoted point 2.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2021-04-01T07:09:14.593" LastActivityDate="2021-04-01T07:09:14.593" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="21045" PostTypeId="2" ParentId="17407" CreationDate="2021-03-31T13:10:05.590" Score="2" Body="&lt;p&gt;Metpy 1.0 has a &lt;a href=&quot;https://unidata.github.io/MetPy/latest/api/generated/metpy.calc.lifted_index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;lifted_index&lt;/a&gt; function, which requires a profile temperature parameter, which in turn can be calculated using the &lt;a href=&quot;https://unidata.github.io/MetPy/latest/api/generated/metpy.calc.parcel_profile.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;parcel_profile&lt;/a&gt; function. That requires having the dew point temperature, which you would either have to have directly, or calculate from another moisture content variable. I'm not sure what your &lt;code&gt;r&lt;/code&gt; variable is, so I'm not sure whether that could help you with such a calculation. Also, rather than using numpy arrays, using &lt;a href=&quot;http://xarray.pydata.org/en/stable/&quot; rel=&quot;nofollow noreferrer&quot;&gt;xarray&lt;/a&gt; for working with netcdf input variables tends to be easier and more efficient.&lt;/p&gt;&#xA;" OwnerUserId="22143" LastActivityDate="2021-03-31T13:10:05.590" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21046" PostTypeId="1" CreationDate="2021-04-01T01:54:40.353" Score="1" ViewCount="82" Body="&lt;p&gt;I have a rainfall data set from a weather station where the data was collected at 20 minutes intervals for 10 years. I would like to peak up the high frequency rainfall cases.&lt;/p&gt;&#xA;&lt;p&gt;What are such rainfalls? How to know them from a data set?&lt;/p&gt;&#xA;" OwnerUserId="3194" LastEditorUserId="2470" LastEditDate="2021-04-01T07:10:52.610" LastActivityDate="2021-04-01T07:10:52.610" Title="How to define high frequency rainfall?" Tags="|rainfall|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21047" PostTypeId="1" CreationDate="2021-04-01T04:44:36.917" Score="2" ViewCount="29" Body="&lt;p&gt;The natural flux of carbon into the atmosphere is about 90 Gt per year. Humans are adding additional carbon dioxide each by burning fossil fuels. Some of it is absorbed by the oceans. The residence time of carbon in the surface ocean with respect to input is about 11 years. How much carbon in the surface ocean?&lt;/p&gt;&#xA;" OwnerUserId="22145" LastEditorUserId="2470" LastEditDate="2021-04-01T07:07:37.427" LastActivityDate="2021-04-01T07:07:37.427" Title="How much carbon in the surface ocean" Tags="|science-fair-project|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21050" PostTypeId="1" CreationDate="2021-04-01T18:23:18.303" Score="3" ViewCount="165" Body="&lt;p&gt;I am interested in identifying the properties of rocks. For example, black opal is shiny and can emit 5 different colors based on different lighting conditions. Is there a way for an amateur to be able to find out the crystal structure and understand why these different lights are being emitted?&lt;/p&gt;&#xA;&lt;p&gt;Also is there a way to guess the chemical property of rocks based on just knowing their composition? If yes, is there something an amateur can self-learn to analyze these?&lt;/p&gt;&#xA;&lt;p&gt;If it requires certain equipment, and I can't theoretically analyze it, I might be able to ask for permission from the chemistry department, so is there something I can do there? Although it'd be great not needing to use that instrument since getting perm is hard.&lt;/p&gt;&#xA;&lt;p&gt;Thanks a lot!&lt;/p&gt;&#xA;" OwnerUserId="22151" LastEditorUserId="6031" LastEditDate="2021-04-03T04:18:46.700" LastActivityDate="2021-04-03T04:54:37.650" Title="How to identify chemical property and structure of rocks?" Tags="|mineralogy|rocks|minerals|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21051" PostTypeId="2" ParentId="21050" CreationDate="2021-04-03T04:54:37.650" Score="2" Body="&lt;p&gt;What you are asking about is &lt;a href=&quot;https://en.wikipedia.org/wiki/Mineralogy&quot; rel=&quot;nofollow noreferrer&quot;&gt;mineralogy&lt;/a&gt;,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;a subject of geology specializing in the scientific study of the chemistry, crystal structure, and physical (including optical) properties of minerals and mineralized artifacts. Specific studies within mineralogy include the processes of mineral origin and formation, classification of minerals, their geographical distribution, as well as their utilization.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It is an &lt;strong&gt;essential&lt;/strong&gt; part of all geology courses. Allied to this is study of how rocks form, &lt;a href=&quot;https://en.wikipedia.org/wiki/Petrology&quot; rel=&quot;nofollow noreferrer&quot;&gt;petrology&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;There is a lot to learn within mineralogy and mineralogists are a specilized group of geologists.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-04-03T04:54:37.650" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21052" PostTypeId="1" AcceptedAnswerId="21053" CreationDate="2021-04-03T10:32:41.883" Score="1" ViewCount="195" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Pleistocene&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pleistocene&lt;/a&gt; shows a switch between &lt;a href=&quot;https://en.wikipedia.org/wiki/Glacial_period&quot; rel=&quot;nofollow noreferrer&quot;&gt;glacial&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Interglacial&quot; rel=&quot;nofollow noreferrer&quot;&gt;interglacial&lt;/a&gt; ages.&lt;/p&gt;&#xA;&lt;p&gt;However, humanity is burning fossil fuels and increasing atmosphere's &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; content.&lt;/p&gt;&#xA;&lt;p&gt;Should we expect a new glacial age after this interglacial or humans will avoid it and &lt;a href=&quot;https://en.wikipedia.org/wiki/Holocene&quot; rel=&quot;nofollow noreferrer&quot;&gt;Holocene&lt;/a&gt; will become a new climatic epoch?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-09-23T06:48:59.483" LastActivityDate="2021-09-23T06:48:59.483" Title="Will a new glacial age take place on Earth or Holocene will become a new climatic epoch?" Tags="|climate-change|climate|paleoclimatology|stratigraphy|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21053" PostTypeId="2" ParentId="21052" CreationDate="2021-04-03T14:56:51.150" Score="2" Body="&lt;p&gt;The reason the Holocene began about 12000 years ago was because that was when Northern Hemisphere summers were hot but short. Those hot summers started a melting process.&lt;/p&gt;&#xA;&lt;p&gt;Right now, July is when the Earth is furthest from the Sun. This makes Northern Hemisphere summers long but mild. That is one of the key conditions that enables a glaciation to start. In particular, glaciations start when summers at high northern latitudes are so mild that all of the snow that accumulated during the previous winter doesn't melt. This triggers a runaway effect by increasing the Earth's albedo. This means the next summer will be even cooler and even more snow and ice will accumulate. Even though we're right about when a glaciation would nominally start, that hasn't happened this time around because of a combination of a lowish eccentricity of the Earth's orbit and a lowish axial tilt (obliquity) of the Earth's orientation, and possibly because of human-generated CO&lt;sub&gt;2&lt;/sub&gt; concentrations in the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;The Earth dodged a glaciation bullet this time around. The next chance for that bullet to hit (aphelion in late June / early July) will be 23 to 26 thousand years from now, and the next one after that, roughly 50 or so thousand years for now. From what I've read, eccentricity and obliquity conditions won't be quite conducive to see the onset of a glaciation the next time around, so the Earth will have to wait 50 or so thousand years to see the possibility of another glaciation.&lt;/p&gt;&#xA;&lt;p&gt;While that isn't our problem, we can help our children's children's children's children's ... children (about 2000 generations worth) survive that potential glaciation threat 50 or so thousand years from now by leaving them with lots of carbon-containing resources to burn. They might well need those hydrocarbons to prevent a glaciation. As a double bonus, stopping burning those hydrocarbons now will make for a much better life for our current generation of children, for their children's children, and for their children's children's children (which brings us to about 2100).&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2021-04-04T22:52:00.447" LastActivityDate="2021-04-04T22:52:00.447" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21054" PostTypeId="1" CreationDate="2021-04-03T15:51:56.957" Score="1" ViewCount="37" Body="&lt;p&gt;Im trying to find out when each of the reports from working groups 1,2 and 3 will be published due to the delay due to covid19. Does anyone have any up to date information about these dates as opposed to reported delays given a year ago?&lt;/p&gt;&#xA;" OwnerUserId="21231" LastActivityDate="2021-04-03T15:51:56.957" Title="When are the IPCC AR6 reports going to be published?" Tags="|climate|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21055" PostTypeId="1" CreationDate="2021-04-03T17:08:54.773" Score="3" ViewCount="1863" Body="&lt;p&gt;I am trying to make sense of the mining process of minerals or metals.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;I found two measures related to waste: the stripping ratio (which is usually larger than 3:1 for copper, i.e. 3 tonnes of waste for one tonne of copper ore) and the ore grade (which is &amp;lt;5% for copper, i.e. out of a tonne of copper, you can extract only 50kg copper). Is my interpretation correct?&lt;/li&gt;&#xA;&lt;li&gt;How do they stack up in the mining process? Using a 1% ore grade and 3:1 stripping ratio, does that mean that to get 1 tonne of copper, we need to move 400 tonnes of earth, as we need 100 copper ore that comes along with 300 tonnes of waste?&lt;/li&gt;&#xA;&lt;li&gt;Does the same logic apply to rare earth mining as well? I found the following numbers for the Bayan Obo mining district in China (see [1]):&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Neodymium content: 18.5%&lt;/li&gt;&#xA;&lt;li&gt;REO(rare earth oxide) grade: 4.1%&lt;/li&gt;&#xA;&lt;li&gt;Recovery rate: 50%&lt;/li&gt;&#xA;&lt;li&gt;Tonne mined/tonne REO: 49&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;So according to my understanding, to get one tonne of neodymium, we need 49/(18.5%*4.1%*50%) = 12920 tonnes. Is that correct? That would be a lot of mining for a tonne of neodymium.&lt;/p&gt;&#xA;&lt;p&gt;Ultimately, I am interested in the amount of earth that has to be moved/mined to get one tonne of copper/other metals (which of course depend of course on the mine and the ore grade).&lt;/p&gt;&#xA;&lt;p&gt;Thanks a lot :-). I am trying to make sense of the numbers to get a better understanding of the footprint of certain technologies (e.g. given that there are 2 tonnes of neodymium in a modern wind generator, we need to remove 26,000 tonnes of earth to get the neodymium for this (if my numbers are correct).&lt;/p&gt;&#xA;&lt;p&gt;Best regards,&#xA;ProGeologist.&lt;/p&gt;&#xA;&lt;p&gt;[1] Rare Earth mining: &lt;a href=&quot;https://ui.adsabs.harvard.edu/abs/2013JOM....65j1327T/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://ui.adsabs.harvard.edu/abs/2013JOM....65j1327T/abstract&lt;/a&gt; - tables on page 1329 and 1331&lt;/p&gt;&#xA;" OwnerUserId="22161" LastActivityDate="2021-04-05T10:52:42.760" Title="How much earth has to be moved to get one tonne of copper" Tags="|geology|mining|rare-earth|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21057" PostTypeId="2" ParentId="21055" CreationDate="2021-04-03T19:27:14.650" Score="0" Body="&lt;p&gt;You need to be specific. In the US , I think copper content of ore is typically 0.03 %. Overburden is irrelevant as the open pit mines do not open new areas. In some areas of the old Belgian Congo ( Zaire ?) copper content is 4 % on the surface of rich ore bodies. They are not generally mined because of political instability. I searched Bagdad ( AZ ) copper mine and found various numbers for copper content. The 0.03 % is probably the poorest ore ; better deposits may be up to 0.5 %.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastEditorUserId="8409" LastEditDate="2021-04-03T19:50:15.243" LastActivityDate="2021-04-03T19:50:15.243" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21058" PostTypeId="2" ParentId="21055" CreationDate="2021-04-04T06:15:33.843" Score="2" Body="&lt;p&gt;Your questions regarding stripping ratio only apply to open pit mines. They produce much more waste rock than underground mines. Typically they mine more waste rock than ore.&lt;/p&gt;&#xA;&lt;p&gt;Underground mines are more surgical and depending on circumstances some of the waste rock they produce is used as backfill in mined out &lt;a href=&quot;https://www.britannica.com/technology/stope&quot; rel=&quot;nofollow noreferrer&quot;&gt;stopes&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;the stripping ratio (which is usually larger than 3:1 for copper, i.e. 3 tonnes of waste for one tonne of copper ore) and the ore grade (which is &amp;lt;5% for copper, i.e. out of a tonne of copper, you can extract only 50kg copper). Is my interpretation correct?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You are partially correct. In this scenario the amount of copper that would be delivered to the processing plant (also known as a mill or concentrator) in mined ore is 50 kg, i.e the amount of metal in the mill feed is 50 kg.&lt;/p&gt;&#xA;&lt;p&gt;To get usable copper metal from the ore, after mining, it needs to treated in a processing plant to concentrate the copper bearing minerals and to remove the &lt;a href=&quot;https://en.wikipedia.org/wiki/Gangue&quot; rel=&quot;nofollow noreferrer&quot;&gt;gangue&lt;/a&gt; minerals. The copper concentrate is then sent to a smelter to produce copper metal. The waste from the concentrator is sent to the tailings dam/pond/storage-facility.&lt;/p&gt;&#xA;&lt;p&gt;If you account for the recoveries of these two processes, typically 80% for concentrating and 90% for smelting, the amount of copper metal produced from 50 kg of copper in mill feed would be 36 kg (50 x 0.8 x 0.9).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;How do they stack up in the mining process? Using a 1% ore grade and 3:1 stripping ratio, does that mean that to get 1 tonne of copper, we need to move 400 tonnes of earth, as we need 100 tonnes copper ore that comes along with 300 tonnes of waste?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Yes. Such a scenario would give you 1 tonne of copper &lt;em&gt;in mill feed&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Unfortunately, the paper you refer to was most likely written by primary metallurgists, or possibly chemical engineers, and not mining engineers. The emphasis of the authors is on the amount of metal recovered from mining and the amount of energy required to produce usable metal from various mining projects, not the overall quantities of material mined.&lt;/p&gt;&#xA;&lt;p&gt;Regarding your question about the Bayan Obo mining district in China your calculations are not correct. Also, from the paper you refer to you cannot obtain the total amount of earth mined, ore and waste, because there is no reference to stripping ratio.&lt;/p&gt;&#xA;&lt;p&gt;As you state, from Table I of your reference, the proportion of neodymium in REM (REM being rare earth metal)is 18.5%. Table II states Tonnes mined/Tonnes REM is 59. This usually refers to the tonnes of &lt;em&gt;&lt;strong&gt;ore&lt;/strong&gt;&lt;/em&gt; mined and supplied to the mill, not the total tonnes of earth mined (ore and waste). Additionally, as stated in Table II and reiterated in Table IX, the recovery from the primary processing plant is 50%.&lt;/p&gt;&#xA;&lt;p&gt;Now, 1 tonne of REM supplied to the mill contains 0.185 t (185 kg) of neodymium. With 59 tonnes of ore mined per tonne of REM, the amount of ore mined and supplied to the mill to get 1 tonne of neodymium is 59/0.185 = 318.9 tonnes.&lt;/p&gt;&#xA;&lt;p&gt;The mill only recovers 50% of the metal supplied to it. Therefore, for the mill to recover 1 tonne of neodymium 637.8 (318.9/0.5) tonnes of ore must be supplied to the mill.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-04-05T10:52:42.760" LastActivityDate="2021-04-05T10:52:42.760" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21060" PostTypeId="1" CreationDate="2021-04-04T12:55:47.350" Score="8" ViewCount="218" Body="&lt;p&gt;So, I just discovered &lt;a href=&quot;https://en.wikipedia.org/wiki/Preliminary_reference_Earth_model&quot; rel=&quot;noreferrer&quot;&gt;PREM (the Preliminary reference Earth model)&lt;/a&gt; which models the density distribution of matter inside the Earth to any depth.&lt;/p&gt;&#xA;&lt;p&gt;The PREM is very convenient but since it only depends on the depth I see that is an isotropic model, meaning that it deoesn't matter from which surface coordinates we are digging, it only accounts for radial variations in density from the core. I know that Earth's interior is not distributed in perfect spherical symmetry since there are things like &lt;a href=&quot;https://en.wikipedia.org/wiki/Large_low-shear-velocity_provinces&quot; rel=&quot;noreferrer&quot;&gt;Large low-shear velocity provinces&lt;/a&gt; and giant &lt;a href=&quot;https://science.sciencemag.org/content/363/6428/736&quot; rel=&quot;noreferrer&quot;&gt;slabs of solid crust floating in the mantle&lt;/a&gt; revealed by &lt;a href=&quot;http://dagik.org/misc/gst/GAP_P4/index.html&quot; rel=&quot;noreferrer&quot;&gt;seismic tomography&lt;/a&gt;, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Gravity_anomaly&quot; rel=&quot;noreferrer&quot;&gt;gravitational anomalies&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I was wondering if there is a much more accurate model for the density distribution of Earth that accounts for the aforementioned asymmetries, and where can I download that data?&lt;/p&gt;&#xA;" OwnerUserId="18279" LastEditorUserId="11430" LastEditDate="2021-05-09T11:44:22.137" LastActivityDate="2024-03-31T02:07:30.863" Title="Where can I find an anisotropic PREM-like model for Earth's interior?" Tags="|geophysics|seismology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21061" PostTypeId="2" ParentId="18768" CreationDate="2021-04-05T02:20:29.023" Score="1" Body="&lt;p&gt;The best chance if the oxydation process leaves a hollow shell which can become a mold for another mineral. The trouble is that ferrous oxide cakes up so the boundary of the original object is chemically and physically blurry.&lt;/p&gt;&#xA;&lt;p&gt;If you have alloys and zinc coatings and paint, that can aid against the blurring effect of rust, so a zinc or vanadium steel will give the mud and sand more time to become a fixed barrier against the steel.&lt;/p&gt;&#xA;&lt;p&gt;There has to be a process which sends dissolved iron away from the steel object while sending a cementing chemical into the steel object. Some micro-organisms can perhaps cement the sediment around the steel fast enough that the steel can completely vanish after a million years and be replaced by iron pyrite/limestone. Ferrihydrite is also good for transporting iron away from the mold.&lt;/p&gt;&#xA;&lt;p&gt;If there is lots of sulphur so that the bacteria can create iron-pyrite inside a sediment/plastic paint shell, then perhaps there will be a bacterial mat that can strongly photograph the steel.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2021-04-05T06:05:35.657" LastActivityDate="2021-04-05T06:05:35.657" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21062" PostTypeId="1" CreationDate="2021-04-05T03:11:42.683" Score="4" ViewCount="67" Body="&lt;p&gt;A fold is composed of stratigraphy that is symmetric and repeated. Cyclic sediments (also called rhythmic sediments) are sequences of sedimentary rocks that are characterised by repetitive patterns of different rock types (strata) or facies within the sequence (wiki). A cycle of sendimentation is usually composed of transgressive and regressive deposition, so the sequences can be also likely symmetric.&lt;/p&gt;&#xA;&lt;p&gt;One method to distinguish them, I think, is the stratigraphic occurrence. Is there other methods that can help distinguish them on a remote sensing image? Thank you.&lt;/p&gt;&#xA;" OwnerUserId="11924" LastEditorDisplayName="user20559" LastEditDate="2021-04-05T13:03:49.263" LastActivityDate="2021-04-05T15:53:26.233" Title="How can we distinguish fold and cycle of sedimentation on a remote sensing image or in the field?" Tags="|geology|remote-sensing|tectonics|structural-geology|stratigraphy|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21064" PostTypeId="1" AcceptedAnswerId="21071" CreationDate="2021-04-06T06:27:04.587" Score="4" ViewCount="3667" Body="&lt;p&gt;Is there a difference between the pollution levels at higher vs lower floors in a high rise building?&lt;/p&gt;&#xA;" OwnerUserId="22169" LastActivityDate="2021-04-09T17:26:03.440" Title="In cities, is the pollution level higher on higher floors?" Tags="|atmosphere|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="21066" PostTypeId="1" AcceptedAnswerId="21070" CreationDate="2021-04-07T00:50:03.457" Score="3" ViewCount="127" Body="&lt;p&gt;In the book, &lt;em&gt;Story of Earth-The First 4.5 Billion Years, From Stardust to Living Planet&lt;/em&gt;, by Robert Hazen, Chapter 3: He discusses the changing mineral composition of the early Earth's crust from continuous heating, cooling, sinking, and remelting. From mafic magnesium rich dunite, anorthite, pyroxene, peridotite, on to today's predominant more felsic silicon enriched basalt and granite/rhyolite.&lt;/p&gt;&#xA;&lt;p&gt;As a book directed at laymen, like myself, he does not mention a term for this process of decomposition of the Earth's early crust.&lt;/p&gt;&#xA;&lt;p&gt;My question then is: What is the term for the process of the early Earth's crust to change its mineral composition over many cycles of melting, rising, cooling and sinking?&lt;/p&gt;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="21875" LastEditorUserId="21875" LastEditDate="2021-05-11T09:24:21.593" LastActivityDate="2021-05-11T09:24:21.593" Title="Term for the Process of the Early Earth's Crust's Changing Mineral Composition" Tags="|geology|minerals|crust|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21067" PostTypeId="1" AcceptedAnswerId="21127" CreationDate="2021-04-07T15:09:47.643" Score="7" ViewCount="734" Body="&lt;p&gt;In 1970, the USSR began drilling at the Kola Super-deep Borehole. The target depth was 15,000 meters;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The stated areas of study were the deep structure of the Baltic Shield, seismic discontinuities and the thermal regime in the Earth's crust, the physical and chemical composition of the deep crust and the transition from upper to lower crust, lithospheric geophysics, and to create and develop technologies for deep geophysical study,&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;according to &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Kola_Superdeep_Borehole&quot; rel=&quot;noreferrer&quot;&gt;its Wikipedia entry.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Data obtained from previous seismic experiments had been interpreted to indicate a transition, which was supposed to be from granite above to basalt below about 7,000 meters. However, one of the surprising findings of the experiment was that there was no such change of kind of rock; the difference was metamorphic, now said to be a result of the changing pressure. Also,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;...the rock at that depth had been thoroughly fractured and was saturated with water, which was surprising. This water, unlike surface water, must have come from deep-crust minerals and had been unable to reach the surface because of a layer of impermeable rock.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The source for this entry is &lt;a href=&quot;https://www.damninteresting.com/the-deepest-hole/&quot; rel=&quot;noreferrer&quot;&gt;Allen Bellows at damninteresting.com&lt;/a&gt; (which coincidentally places the supposed granite-basalt transition at &amp;quot;3-6 km&amp;quot;):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Because free water should not be found at those depths, scientists theorize that the water is comprised of hydrogen and oxygen atoms which were squeezed out of the surrounding rocks due to the incredible pressure.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So, why should water not be found at those depths? Based on what assumptions were people surprised to find water there? Or was it only journalists who were surprised?&lt;/p&gt;&#xA;&lt;p&gt;I'm sorry I don't have more initial research; the truth is I don't know where to start looking. Online searches only give me results like &lt;a href=&quot;https://www.sciencemag.org/news/2018/03/pockets-water-may-lay-deep-below-earth-s-surface&quot; rel=&quot;noreferrer&quot;&gt;this article at Science Magazine&lt;/a&gt;, which is related only because in its case, too, water is supposed to be &amp;quot;squeezed out&amp;quot; of rock, synthesized, as it were from its chemical components. (I asked this question at Codidact.physics, but it seems to need the broader context of geology)&lt;/p&gt;&#xA;&lt;p&gt;Related: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7888/what-do-continents-lay-on&quot;&gt;What do continents &amp;quot;lay&amp;quot; on?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22186" LastEditorUserId="2958" LastEditDate="2021-04-08T17:23:13.647" LastActivityDate="2023-01-25T23:36:09.830" Title="Why should there not be water deep (e.g. below 6 kms) in the Earth's crust?" Tags="|oceanography|water|groundwater|crust|pressure|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="21068" PostTypeId="1" CreationDate="2021-04-07T16:31:21.867" Score="2" ViewCount="214" Body="&lt;p&gt;Looking at the index files in &lt;code&gt;https://ftp.ncep.noaa.gov/data/nccf/com/gfs/prod/&lt;/code&gt;, there's no probability of precipitation (POP) data provided. (There is a probability of frozen precipitation.)&lt;/p&gt;&#xA;&lt;p&gt;Is there a way to derive a POP (using the NWS 0.01 inch standard, or some other standard) from the other values provided like the precipitation rate (PRATE) value?&lt;/p&gt;&#xA;&lt;p&gt;The model output statistics in the GFS data provides POP values for a number of domestic airports, but I'm interested in worldwide, hourly POP.&lt;/p&gt;&#xA;" OwnerUserId="22188" LastEditorUserId="2958" LastEditDate="2021-04-09T03:45:27.360" LastActivityDate="2021-04-09T03:45:27.360" Title="Determining probability of precipitation from GFS data" Tags="|meteorology|gfs|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21069" PostTypeId="1" CreationDate="2021-04-07T18:16:42.473" Score="1" ViewCount="50" Body="&lt;p&gt;Apologies for the vagueness of this query, but generally, would it be plausible to state that the prevalence of 'sub-rounded'* beach fabric is more common at the foreshore than 'sub-angular'* beach fabric? This is in the context of a completely hypothetical scenario.&lt;/p&gt;&#xA;&lt;p&gt;(These descriptions denoted by '*' are referenced the Power's Angularity Index of Smoothness)&lt;/p&gt;&#xA;" OwnerUserId="7924" LastEditorUserId="2958" LastEditDate="2021-04-10T07:19:38.080" LastActivityDate="2021-04-10T07:19:38.080" Title="Prevalence of 'well-rounded' beach fabric on the Foreshore" Tags="|rocks|data-analysis|erosion|coastal|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21070" PostTypeId="2" ParentId="21066" CreationDate="2021-04-08T06:28:38.847" Score="1" Body="&lt;p&gt;The term you are searching for is differentiation. In Early Earth the Crust was mafic. Remelting cycles created an enrichment in silica and alkali elements, forming basalts and granites.&lt;/p&gt;&#xA;&lt;p&gt;As it happens on Continental Crust it is commonly referred as Differentiation of the Continental Crust.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Hacker, B.R. et al (2011):&lt;/strong&gt; &amp;quot;Differentiation of the continental crust by relamination&amp;quot;,&#xA;&lt;em&gt;Earth and Planetary Science Letters&lt;/em&gt;, Volume 307, Issues 3â€“4, Pages 501-516, ISSN 0012-821X, &lt;a href=&quot;https://doi.org/10.1016/j.epsl.2011.05.024&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/j.epsl.2011.05.024&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-04-08T09:59:52.790" LastActivityDate="2021-04-08T09:59:52.790" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21071" PostTypeId="2" ParentId="21064" CreationDate="2021-04-09T09:35:49.130" Score="2" Body="&lt;p&gt;Yes, the higher floors will have less pollution than the street level.&lt;/p&gt;&#xA;&lt;p&gt;The wind rises as a function of altitude, so the street will have less new air coming in, on average:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Dd5d8.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Dd5d8.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Some of the pollutants are lighter than air, i.e. Ozone, and some are heavier, i.e. particulate matter, they tend to rise or fall very slowly, so they can be slightly different gradients at different floors of the building.&lt;/p&gt;&#xA;&lt;p&gt;The pollutants are diffuse clouds that rely on ambient air currents for dispersion.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="3315" LastEditDate="2021-04-09T17:26:03.440" LastActivityDate="2021-04-09T17:26:03.440" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21072" PostTypeId="1" AcceptedAnswerId="21135" CreationDate="2021-04-09T15:16:36.840" Score="4" ViewCount="58" Body="&lt;p&gt;In many sources (&lt;a href=&quot;https://glossary.ametsoc.org/wiki/Bulk_richardson_number&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://glossary.ametsoc.org/wiki/Bulk_richardson_number&lt;/a&gt;), bulk Richardson number is defined as an approximation to gradient Richardson number. The prior only approaches the ladder when layer thickness, &lt;span class=&quot;math-container&quot;&gt;$\Delta z$&lt;/span&gt; becomes &amp;quot;small&amp;quot;. What is small defined as? For example, comparison of simulation domain to &lt;span class=&quot;math-container&quot;&gt;$\Delta z$&lt;/span&gt;, overall length &lt;span class=&quot;math-container&quot;&gt;$\Delta z$&lt;/span&gt; approaches 0, or etc?&lt;/p&gt;&#xA;" OwnerUserId="18151" LastEditorUserId="6" LastEditDate="2021-04-21T19:21:14.180" LastActivityDate="2021-04-21T19:21:14.180" Title="What is &quot;small layer thickness&quot; defined as in terms of bulk Richardson number approaching gradient Richardson number?" Tags="|meteorology|atmosphere|fluid-dynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21073" PostTypeId="1" CreationDate="2021-04-10T10:01:08.190" Score="2" ViewCount="35" Body="&lt;p&gt;It is possible to evaluate the geological structure of a basin based on gravimetric data. But if one doesn't have gravimetric data, how can one learn the geological structure and properties of a certain horizon in the basin according to the density of rocks?&lt;/p&gt;&#xA;" OwnerUserId="22150" LastEditorUserId="2470" LastEditDate="2021-04-10T16:01:57.630" LastActivityDate="2021-04-10T16:01:57.630" Title="Learn geological properties of the horizon through density of the rocks" Tags="|tectonics|gravity|horizon|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21074" PostTypeId="1" CreationDate="2021-04-10T12:59:15.507" Score="1" ViewCount="47" Body="&lt;p&gt;There are so many websites giving numbers for 'average' lifetimes of global-warming or ozone-depleting chemicals in the atmosphere, yet they are rarely explicit in their definition(s)...&lt;/p&gt;&#xA;&lt;p&gt;For instance, methane is usually stated to last 12.4 years....  But is this half-life (of a large amount) or mean lifetime (of a single molecule)?&lt;/p&gt;&#xA;" OwnerUserId="20985" LastActivityDate="2021-04-10T12:59:15.507" Title="When it comes the average lifetime of chemicals in the atmosphere, is the mean lifetime ~1.4427 times the half-life? As with radioactivity?" Tags="|atmosphere|climate-change|atmospheric-chemistry|global-weirding|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21075" PostTypeId="1" CreationDate="2021-04-10T20:56:39.837" Score="6" ViewCount="409" Body="&lt;p&gt;I read online that it is scientifically proven that pollen particles can trigger cloud formation&#xA;&amp;quot;is that true&amp;quot;?&#xA;if true ,does it mean that no clouds can be formed without pollen particles' role?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Is it scientifically proven that some clouds can be formed without a pollen particle's role?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="22212" LastActivityDate="2021-04-11T19:26:13.837" Title="Can clouds be formed without a pollen particle's role?" Tags="|atmosphere|climate|clouds|rain|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21076" PostTypeId="2" ParentId="21075" CreationDate="2021-04-11T03:35:59.410" Score="9" Body="&lt;p&gt;Pollen is one of many types of &lt;a href=&quot;https://en.wikipedia.org/wiki/Cloud_condensation_nuclei&quot; rel=&quot;noreferrer&quot;&gt;cloud condensation nuclei&lt;/a&gt; (CCN). So can you make clouds without pollen? Yes, but you still need other sources of CC. Don’t fall into the false dilemma that pollen is a requirement for cloud formation. The more soluble the CCN is, the easier it is to form a cloud (&lt;a href=&quot;https://en.wikipedia.org/wiki/K%C3%B6hler_theory&quot; rel=&quot;noreferrer&quot;&gt;see Koehler theory&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;Can a cloud be formed without CCN? I saw it once calculated that it would take longer than the age of the universe for something like that to occur.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-04-11T03:35:59.410" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21077" PostTypeId="1" AcceptedAnswerId="21096" CreationDate="2021-04-11T10:18:24.333" Score="2" ViewCount="165" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_engineering#Proposed_strategies&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia page for geoengineering entry&lt;/a&gt; list a lot of proposals to decrease global temperature:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Solar radiation management&lt;/strong&gt; methods[5] may include:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Surface-based: for example, surface-based mirror infrastructures,[29]    protecting or expanding polar sea ice and&#xA;glaciers, including the use    of insulating blankets or artificial&#xA;snow,[30][31] using pale-colors    for roofing materials and other&#xA;man-made surfaces (i.e. roadways and    exterior paints), attempting&#xA;to change the oceans' brightness,    growing high-albedo crops, or by&#xA;distributing hollow glass beads in    selected areas to increase ice&#xA;coverage and lower temperatures.[32]&lt;/li&gt;&#xA;&lt;li&gt;Troposphere-based: for example, marine cloud brightening, which would    spray fine sea water to whiten clouds and thus increase cloud&#xA;reflectivity.&lt;/li&gt;&#xA;&lt;li&gt;Upper atmosphere-based: creating reflective aerosols,    such as    stratospheric sulfate aerosols, specifically designed&lt;br /&gt;&#xA;self-levitating aerosols,[33] or other substances.&lt;/li&gt;&#xA;&lt;li&gt;Space-based: space    sunshade – obstructing solar radiation with    space-based mirrors,    dust,[34] etc.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;Carbon dioxide removal&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Creating biochar (i.e. in biomass-fired thermal power plants), for    mixing into the soil to create terra preta&lt;/li&gt;&#xA;&lt;li&gt;Bio-energy with carbon capture and storage to sequester carbon and    simultaneously provide energy Carbon air capture to remove carbon&lt;br /&gt;&#xA;dioxide from ambient air&lt;/li&gt;&#xA;&lt;li&gt;Afforestation, reforestation and forest restoration to absorb carbon    dioxide&lt;/li&gt;&#xA;&lt;li&gt;Ocean afforestation and ocean fertilization (which includes iron    fertilization of the oceans)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Why have none of these methods been implemented?&lt;/p&gt;&#xA;&lt;p&gt;What are the risks of developing geoengineering?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-09-22T12:53:11.560" LastActivityDate="2021-09-22T12:53:11.560" Title="What are the risks of developing geoengineering?" Tags="|climate-change|carbon-cycle|forest|geoengineering|light|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21078" PostTypeId="1" AcceptedAnswerId="21080" CreationDate="2021-04-11T15:07:55.673" Score="3" ViewCount="205" Body="&lt;p&gt;Outside my window it's snowing.&lt;/p&gt;&#xA;&lt;p&gt;This isn't so strange, even for the South of England in mid-April. What is surprising is that the ambient air temperatures (according to the Met-Office) are about 7 or 8 degrees. Normally one would expect any snowflakes that formed in the clouds to have melted long before they reached the ground. Normally if the air temperature is more than 1 or 2 degrees, we get rain.&lt;/p&gt;&#xA;&lt;p&gt;So what conditions can combine to allow for snow at temperatures above 5 degrees?&lt;/p&gt;&#xA;&lt;p&gt;Conversely what conditions normally allow for rain at temperatures a little over freezing.&lt;/p&gt;&#xA;&lt;p&gt;I note that there has been a steady northerly airflow for several days, and temperatures are well below normal (we would expect about 14 degrees at this time of year).  The clouds are Cumulus mediocris, and the snow is falling in very short showers of light intensity. The cloud base appears relatively high (but hard to estimate) The humidity is low (40%) and pressure is high at about 1020 mBa (Met Office values), and the snow melts rapidly when it reaches the ground.&lt;/p&gt;&#xA;&lt;p&gt;I'm aware that a temperature inversion can result in freezing rain.  Is snow on relatively warm days caused by a very high lapse rate, and so extreme cold temperatures at cloud level?&lt;/p&gt;&#xA;" OwnerUserId="9563" LastActivityDate="2021-04-15T03:55:47.677" Title="Snow on a relatively warm day" Tags="|meteorology|snow|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21080" PostTypeId="2" ParentId="21078" CreationDate="2021-04-11T20:45:34.480" Score="5" Body="&lt;p&gt;Not being a winter precipitation expert by any stretch (we avoid such silliness in Florida!), I think a significant key may be the &amp;quot;&lt;strong&gt;the humidity is low (40%)&lt;/strong&gt;&amp;quot; part.&lt;/p&gt;&#xA;&lt;p&gt;When winter precipitation falls through warm air, it certainly gets heated by the air.  But if the air is dry, some of the outer fringes of the precipitation will melt\sublimate, taking away energy and thereby cooling the flake, helping it to survive longer.  &lt;a href=&quot;http://www.sciencebits.com/SnowAboveFreezing&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.sciencebits.com/SnowAboveFreezing&lt;/a&gt; looks to have a pretty great detailed page about the nitty gritty of it.&lt;/p&gt;&#xA;&lt;p&gt;Certainly precipitation starting at colder temperatures gives the particle a little reserve.  The low conductivity and high specific heat capacity of water\ice are also notable.  But the latent heat of sublimation is over 10 times as great as the specific heat capacity, showing that losing a little ice on the surface can really counteract quite a bit of warming.&lt;/p&gt;&#xA;&lt;hr&gt;&#xA;&lt;p&gt;But it's important to note that at the values you gave, the &lt;a href=&quot;http://www.sciencebits.com/SnowProbCalc?calc=yes&quot; rel=&quot;nofollow noreferrer&quot;&gt;ScienceBits calculator&lt;/a&gt; doesn't give any hopes of snow.  So what's going on?&lt;/p&gt;&#xA;&lt;p&gt;First, it's important to impart that the temp\humidity values aren't far off (try RH=30% and T=7°C or RH=40% and T=6°C and you'll start to get values).&lt;/p&gt;&#xA;&lt;p&gt;So I am indeed convinced that your local values were off by around that amount.&lt;/p&gt;&#xA;&lt;p&gt;You can reasonably expect that the temperature that an app or website gives typically has error of a few degrees (with similar errors in most other variables) unless you happen to be right at the location of a reporting site.&lt;/p&gt;&#xA;&lt;p&gt;This is due to variations over space and time.&lt;br /&gt;&#xA;Even small elevation changes  &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9038/why-is-it-colder-in-the-mountains-than-at-sea-level&quot;&gt;cause significant impact on temperatures&lt;/a&gt;, and &lt;a href=&quot;https://www.njweather.org/maps/mapviewer?mapname=temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;the current data&lt;/a&gt; for a relatively flat place like New Jersey shows how other microscale effects (like surface color, roughness, wind blocking, and water\plant moisture) typically lead to at least a degree or two variation between even well-sited representative locations (not even broaching the bigger changes things like concrete, buildings, trees, rock formations, etc cause).&lt;br /&gt;&#xA;In addition, most weather sites only give full reports once per hour... and we certainly know how things can change in an hour, especially in the morning\evening or near fronts.&lt;/p&gt;&#xA;&lt;p&gt;In addition, there are three ways your app\website will give you the temperature and other variables:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;They just give the reading at the closest official weather reporting station.  For instance &lt;a href=&quot;http://weather.gov&quot; rel=&quot;nofollow noreferrer&quot;&gt;weather.gov&lt;/a&gt;, the US Weather Service page, will do this.  Full &lt;a href=&quot;https://www.ncdc.noaa.gov/news/picture-climate-automated-surface-observing-system-ASOS&quot; rel=&quot;nofollow noreferrer&quot;&gt;ASOS reporting stations&lt;/a&gt; are about &lt;a href=&quot;https://www.wolframalpha.com/input/?i=sqrt%28%28area%20contiguous%20us%29%2F900%29&quot; rel=&quot;nofollow noreferrer&quot;&gt;60 miles apart on average&lt;/a&gt; in the contiguous US.  You can peruse &lt;a href=&quot;http://meteocentre.com/analysis/map-surface.php?lang=en&amp;amp;area=uk&quot; rel=&quot;nofollow noreferrer&quot;&gt;this site&lt;/a&gt; to see the stations in the UK or other parts of the world, but in general they're reasonably far apart.  Mesonets and private weather stations offer more options, but are usually not available to apps\weather service use, and often inconsistently calibrated\sited.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Some websites give a weighted average of nearby values... but this still won't generally include elevation effects at all.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;And some use &lt;a href=&quot;https://www.pivotalweather.com/model.php?fh=loop&amp;amp;dpdt=&amp;amp;mc=&amp;amp;r=uk&amp;amp;p=sfct_b&amp;amp;m=gfs&quot; rel=&quot;nofollow noreferrer&quot;&gt;weather models&lt;/a&gt; to fill in the gaps and estimate to a higher degree for your location, properly incorporating some elevation data along with the fundamental meteorological equations.  However the resolution (and initial data) is often still poor enough that it doesn't match reality.  I believe the highest resolution forecast\analysis models right now is only 3km, and those are only in limited spots like the US (&lt;a href=&quot;https://www.weathernerds.org/models/hrrr.html?&amp;amp;inittype=zoom&amp;amp;initfield=Temperature_Surface&amp;amp;initcycle=determine&amp;amp;initfhour=000&amp;amp;initimdimx=1050&amp;amp;initimdimy=630&amp;amp;initrange=55.000000000000:230.000000000000:20.000000000000:300.000000000000&amp;amp;initcx1=0&amp;amp;initcy1=0&amp;amp;initcx2=0&amp;amp;initcy2=0&amp;amp;initcross=False&amp;amp;initsound=False&amp;amp;initsoundx=1&amp;amp;initsoundy=1&amp;amp;initloop=False&amp;amp;initoverlay=False&amp;amp;initlstart=000&amp;amp;initlend=048&amp;amp;initlint=1&amp;amp;initol1=Temperature_Surface&amp;amp;initol2=null&amp;amp;initol3=null&amp;amp;initol4=null&amp;amp;initol5=null&amp;amp;initcities=On&amp;amp;inithgwys=On&amp;amp;initunits=On&amp;amp;initlatlon=Off&quot; rel=&quot;nofollow noreferrer&quot;&gt;HRRR&lt;/a&gt;, &lt;a href=&quot;https://www.weathernerds.org/models/nam3km.html?&amp;amp;inittype=zoom&amp;amp;initfield=Temperature_Surface&amp;amp;initcycle=determine&amp;amp;initfhour=003&amp;amp;initimdimx=1050&amp;amp;initimdimy=630&amp;amp;initrange=55.000000000000:230.000000000000:20.000000000000:300.000000000000&amp;amp;initcx1=0&amp;amp;initcy1=0&amp;amp;initcx2=0&amp;amp;initcy2=0&amp;amp;initcross=False&amp;amp;initsound=False&amp;amp;initsoundx=1&amp;amp;initsoundy=1&amp;amp;initloop=False&amp;amp;initoverlay=False&amp;amp;initlstart=000&amp;amp;initlend=060&amp;amp;initlint=3&amp;amp;initol1=Temperature_Surface&amp;amp;initol2=null&amp;amp;initol3=null&amp;amp;initol4=null&amp;amp;initol5=null&amp;amp;initcities=On&amp;amp;inithgwys=On&amp;amp;initunits=On&amp;amp;initlatlon=Off&quot; rel=&quot;nofollow noreferrer&quot;&gt;NAM)&lt;/a&gt;).  Most models only offer values three hours apart as well, and are only run every 6-12 hours, so the data is far from precise.  Here is the Global Forecast System model forecast for 4 PM BDT (1500 UTC):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/3PeYWm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3PeYWm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;You can see some hints of the terrain in a few spots, but nearly the fine variation reality has.&lt;br /&gt;&#xA;This model only has a 10 km resolution, so many of the smaller hills around your area aren't included at all.&lt;br /&gt;&#xA;Here's a topography image for a similar scale model, the &lt;a href=&quot;https://www.dwd.de/EN/research/weatherforecasting/num_modelling/01_num_weather_prediction_modells/icon_description.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;European ICON model&lt;/a&gt; (13 km res):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gUcYjm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gUcYjm.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;You can see the North Downs fairly well, and certainly some hint of the hills and valleys around your area.  But they likely aren't well enough represented to truly incorporate the differences in weather in such complex areas.&lt;/p&gt;&#xA;&lt;p&gt;Likewise it looks like your closest site on Met Office's &lt;a href=&quot;https://www.metoffice.gov.uk/public/weather/observation/map#?map=Temperature&amp;amp;zoom=8&amp;amp;lon=-0.68&amp;amp;lat=51.22&amp;amp;fcTime=1618225200&quot; rel=&quot;nofollow noreferrer&quot;&gt;observation map&lt;/a&gt; is Charlwood (though an &lt;a href=&quot;http://weather.rap.ucar.edu/surface/stations.txt&quot; rel=&quot;nofollow noreferrer&quot;&gt;international list&lt;/a&gt; suggests siting at Gatwick... perhaps they're really the same site?)&#xA;Remarkably the &lt;a href=&quot;https://www.wunderground.com/history/daily/gb/gatwick-airport/EGKK/date/2021-4-11&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gatwick observations&lt;/a&gt; from that day actually indicated 9°C at 1600 BST.  Still it's a good 6+ miles away.  And there's also about &lt;a href=&quot;https://en-ca.topographic-map.com/maps/ob23/Sussex/&quot; rel=&quot;nofollow noreferrer&quot;&gt;70 meters elevation difference&lt;/a&gt; between East Grinstead and Gatwick\Charlwood.  It's worth noting that in confirmation at Gatwick there were only rain reports until it got down to freezing after midnight.&lt;/p&gt;&#xA;&lt;hr&gt;&#xA;&lt;p&gt;Finally as you asked about the vertical profile, here is the model forecast sounding from about that time:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3vTmP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3vTmP.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Additionally you can get the SkewT or a table of the actual UK data from the Camborne launch site from 12Z (1 PM BST) at &lt;a href=&quot;http://weather.uwyo.edu/upperair/sounding.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this website&lt;/a&gt; to compare. [&lt;a href=&quot;http://www.theweatherprediction.com/thermo/skewt/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's a site&lt;/a&gt; with a bit of info on reading such diagrams].&lt;br /&gt;&#xA;I originally opined that I didn't think a high lapse rate should be likely since those tend more towards deep convection\thunderstorms.  However the data shows I'm sufficiently wrong... looks like over the lowest km, there's a remarkable 11.2°C decrease, &lt;a href=&quot;http://www.theweatherprediction.com/habyhints/31/&quot; rel=&quot;nofollow noreferrer&quot;&gt;the rare superadiabatic lapse rate&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Still, even that profile only leads to an LCL temperature of around -5°C (&lt;a href=&quot;http://www.csgnetwork.com/lclcalc.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;calculated&lt;/a&gt; as -4.5°C on the Camford sounding, -6.2°C on the GFS sounding using Gatwick surface pressure), which represents the cloud base of a lifted surface-based parcel at those locations (obs at Gatwick are similar).  However with such a lapse rate, by the time the parcel tops out near equilibrium level (which is a rough idea of the maximum cloud top height for a surface parcel)... it's nearer -20°C.  Certainly colder, though perhaps not what I'd think of as extreme.&lt;/p&gt;&#xA;&lt;p&gt;But you were clearly right to think that the lapse right could be high... in retrospect it makes sense as for surface air to rise air enough for precipitation to fall despite a stout T\Td spread it'd need to rise a fair bit, likely needing decent lapse rates.  My mistake was that the instability (a rough proxy of the rate air would rise at freely [so not including the impacts of the dynamical lift of the storm system]) such great lapse rates produce is tiny (only a few J/kg on this sounding, compared to hundreds or thousands in severe thunderstorms typically)... this is because such cold air doesn't hold nearly as much moisture.&lt;/p&gt;&#xA;&lt;p&gt;So it's quite possible to indeed get big lapse rates in cold weather and get the types of clouds you saw.  That just may not mean cloud temperatures are particularly extreme, in part because cold weather clouds tend to be more shallow due to the reduction in moist adiabat temperature gains.&lt;/p&gt;&#xA;&lt;hr&gt;&#xA;&lt;p&gt;In the end, I really believe the temperature was likely a few degrees lower in East Grinstead than in those surrounding areas.  Not only because of the resolution of data... but also in particular because of the weather: a persistent decent northwest wind most of the day, which flows roughly into the sharpest larger-scale terrain gradient in your area.  That would tend to force a lot of ascent, likely developing initial clouds which gradually precipitated down but not reaching to the surface... evaporating fully, but at the same time reducing the air temperature and increasing the dew point below (a process called wet bulbing), until the low-level values became more reasonable for precipitation around the hills.  I'd expect you know this type of pattern very well from the many foggy rainy days that are likely near moors like yours.  That localized process, coupled with the fairly cool temperatures deeper within the cloud, likely were enough to get the sporadic snow showers.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2021-04-15T03:55:47.677" LastActivityDate="2021-04-15T03:55:47.677" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="21081" PostTypeId="1" CreationDate="2021-04-12T14:06:29.590" Score="2" ViewCount="60" Body="&lt;p&gt;In this video of &lt;a href=&quot;https://youtu.be/rr6DDKd26QE?t=74&quot; rel=&quot;nofollow noreferrer&quot;&gt;sunrise at Cadillac Mountain, Maine&lt;/a&gt;, the landscape closer to the horizon appears to brighten sooner than the foreground. It makes sense to me, the terrain at the horizon is experiencing the sunrise before the terrain at the water level in the foreground. I'm wondering what is the minimum height someone would have to be see the difference in the brightness on the ground in the distance to the brightness on the ground nearby.&lt;/p&gt;&#xA;&lt;p&gt;For example, if from 200' high one can see at least 15 miles to the horizon, and the sun rises over a minute earlier 15 miles away from the observer, would the observer be able to see a difference in the brightness of the two locations?&lt;/p&gt;&#xA;&lt;p&gt;I'm assuming a latitude of 50°N.&lt;/p&gt;&#xA;" OwnerUserId="14986" LastEditorUserId="14986" LastEditDate="2021-04-13T04:48:05.253" LastActivityDate="2021-04-13T04:48:05.253" Title="Seeing a varied change in brightness across the landscape during sunrise?" Tags="|sun|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21082" PostTypeId="2" ParentId="21078" CreationDate="2021-04-12T17:54:05.643" Score="3" Body="&lt;p&gt;In short: You may think about &lt;a href=&quot;https://en.wikipedia.org/wiki/Hail&quot; rel=&quot;nofollow noreferrer&quot;&gt;hail&lt;/a&gt; and the smaller grains of &lt;a href=&quot;https://en.wikipedia.org/wiki/Graupel&quot; rel=&quot;nofollow noreferrer&quot;&gt;graupel&lt;/a&gt; like super cooled frozen bits of solid water ice which fall this fast to the earth's surface that there is not enough time to reach it liquid, as rain.&lt;/p&gt;&#xA;&lt;p&gt;Here, &lt;em&gt;fast&lt;/em&gt;  does not necessarily refer to their velocity approaching the earth's surface.   But it takes time that the temperature gradient between the surrounding atmosphere and the inner of the ice core flattens, and ambient temperature above &lt;span class=&quot;math-container&quot;&gt;$\pu{0 ^\circ{}C}$&lt;/span&gt; penetrates the whole body of the ice core.  If you apply the heat equation (quite similar to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Fick%27s_laws_of_diffusion#Fick%27s_second_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;second law of diffusion)&lt;/a&gt;, using the illustration below, the inner of such an ice particle would be solid ice (on the right hand side, &lt;span class=&quot;math-container&quot;&gt;$x = 1$&lt;/span&gt;) as long as the temperature has not risen to &lt;span class=&quot;math-container&quot;&gt;$u = 0.5$&lt;/span&gt;.  (The limitation of the illustration is that the outer temperature at &lt;span class=&quot;math-container&quot;&gt;$x = 0$&lt;/span&gt; may stay greater than the particle's inner temperature when the particle approaches the earth's surface):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QGGvw.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QGGvw.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(&lt;a href=&quot;https://en.wikipedia.org/wiki/Heat_equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;credit&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;Which is why the abovementioned wikipedia article may depict a picture about hail in Sydney, Australia, April 2015, too.&lt;/p&gt;&#xA;" OwnerUserId="18990" LastActivityDate="2021-04-12T17:54:05.643" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21083" PostTypeId="1" CreationDate="2021-04-12T22:27:12.643" Score="6" ViewCount="8913" Body="&lt;p&gt;I have never heard an explanation as to what  traps GHGs. What holds them in place? Has research been conducted to assess the efficacy of say triggering a change in their chemical composition into a compound that would render them inert or less impactful or 'setting them free' so to speak?&lt;/p&gt;&#xA;" OwnerUserId="22257" LastActivityDate="2021-04-13T14:18:34.423" Title="Why don't green house gases escape into space?" Tags="|climate|greenhouse-gases|" AnswerCount="4" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="21084" PostTypeId="2" ParentId="21083" CreationDate="2021-04-12T22:45:20.497" Score="26" Body="&lt;p&gt;The reason the atmosphere (including GHGs) stays attached to the earth is gravity. This is called the &lt;a href=&quot;https://www.e-education.psu.edu/meteo300/node/7&quot; rel=&quot;noreferrer&quot;&gt;Hydrostatic Equilibrium&lt;/a&gt;. There is one GHG that this does not fully apply to: water vapor. While water vapor can be considered to be in hydrostatic balance, the fact that it undergoes a phase change (&lt;a href=&quot;https://www.quora.com/How-much-water-is-lost-into-space-each-day&quot; rel=&quot;noreferrer&quot;&gt;and becomes dissociated if it reaches too far up&lt;/a&gt;) prevents it from being more evenly distributed vertically like &lt;span class=&quot;math-container&quot;&gt;$\ce{CO_2}$&lt;/span&gt; or &lt;span class=&quot;math-container&quot;&gt;$\ce{CH_4}$&lt;/span&gt;.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-04-12T22:45:20.497" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21085" PostTypeId="2" ParentId="21083" CreationDate="2021-04-12T22:51:55.500" Score="14" Body="&lt;p&gt;Trapping compounds and changing composition are two very different things.&lt;/p&gt;&#xA;&lt;p&gt;The composition of an atmosphere is set by equilibrium chemistry. Equilibrium chemistry can be understood as mapping of a set of input atoms into molecules and remaining atoms. For example, at the given numbers of N, O, C, H... and given temperature and pressure, one will always find the same amount of GHG, e.g. &lt;span class=&quot;math-container&quot;&gt;$\rm CO_2$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\rm CH_4$&lt;/span&gt;, etc.&#xA;Hence, changing the amount of GHG would require to remove atoms first, i.e. split molecules in the first place. The latter requires some kind of large-scale chemical or photoionization processes.&lt;/p&gt;&#xA;&lt;p&gt;The actual trapping in Earth's gravitational well, just as Venus', is due to the high molecular weight of GHG's, keeping most of the GHG gas in the troposphere. There is some upwards loss to space however. This process is strongest in a planets early history when the light hydrogen carries the heavier GHGs along. Nowadays the upwards loss is controlled via upwards diffusion, limited by 'cold traps' in atmospheres.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2021-04-12T22:51:55.500" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="21086" PostTypeId="2" ParentId="21081" CreationDate="2021-04-13T02:40:26.350" Score="1" Body="&lt;p&gt;TL;DR: It certainly is possible from a geosynchronous orbit, an altitude of 35786 km. It is also possible from a very high altitude weather balloon.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;A key issue is that the terminator is not a line. Thanks to the Earth's atmosphere, the terminator is instead a band that is about 1000 km across that gradually transitions from sunlit to dark. At most latitudes sunlight notably  starts to decrease at least 10 minutes before sunset, but one can continue with outdoor activities for a half hour or more  after sunset. (The reverse is true for sunrise.) That 40 minute period or longer time span corresponds to a very wide band. Even an SR-71 could barely have seen that ~1000 km wide band that transitioned from sunlit to dark.&lt;/p&gt;&#xA;&lt;p&gt;In addition to barely being high enough, another issue with an SR-71 was that they moved so fast. Something that flies even higher than did an SR-71 but flies much, much slower than an SR-71 is needed. That would be a high altitude weather balloon. A high altitude weather balloon (30 km or higher) could see both the bright and bright sides of that 1000 km band, and it could see that band slowly moving.&lt;/p&gt;&#xA;&lt;p&gt;Even higher up (much higher up), that widish band doesn't look at that wide from the perspective of a geostationary satellite. Now it does looks a bit like a line. Just as is the case with a geostationary high altitude weather balloon, a geostationary satellite would be able to see the terminator (now a line rather than a band) move over the more or less stationary Earth.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2021-04-13T02:49:47.693" LastActivityDate="2021-04-13T02:49:47.693" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21087" PostTypeId="1" CreationDate="2021-04-13T12:10:35.427" Score="4" ViewCount="52" Body="&lt;p&gt;Today in the news Japan has announced it will discharge water from Fukushima.&#xA;All news sites I have looked at covering this give very little detail, only that about 1.4M Tonnes of water will be discharged, that it contains tritium, and that various groups and countries protest.&#xA;e.g &lt;a href=&quot;https://www.theguardian.com/environment/2021/apr/13/fukushima-japan-to-start-dumping-contaminated-water-pacific-ocean&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.theguardian.com/environment/2021/apr/13/fukushima-japan-to-start-dumping-contaminated-water-pacific-ocean&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The IAEA themselves support the discharge, but their latest press release also contains no real data.&#xA;&lt;a href=&quot;https://www.iaea.org/newscenter/pressreleases/iaea-ready-to-support-japan-on-fukushima-water-disposal-director-general-grossi-says&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.iaea.org/newscenter/pressreleases/iaea-ready-to-support-japan-on-fukushima-water-disposal-director-general-grossi-says&lt;/a&gt;&#xA;In the video attached there, they say the IAEA will help with the implementation of a plan, without being clear if the plan exists.&lt;/p&gt;&#xA;&lt;p&gt;I assume a thorough analysis will include all radio nucleides in the water, a discharge plan that keeps all of these within certain limits in the sea water. I expect it to address issue like: What is initial discharge process? What monitoring is done? How will this feedback into the discharge process? Must discharge follow certain tidal flows? Might it be halted under storm conditions, or take into account seasonal variation in sea-life?&lt;/p&gt;&#xA;&lt;p&gt;Has such an analysis been published?&lt;/p&gt;&#xA;" OwnerUserId="22274" LastActivityDate="2021-04-13T12:10:35.427" Title="Is there open scientific analysis of the proposed discharge of water from Fukushima?" Tags="|environmental-protection|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21088" PostTypeId="2" ParentId="21083" CreationDate="2021-04-13T13:39:18.407" Score="1" Body="&lt;p&gt;Simplest explanation I can think of (hopefully no logical mistakes in it): &lt;strong&gt;gases&lt;/strong&gt;, just like liquids, &lt;strong&gt;are &lt;em&gt;fluids&lt;/em&gt;&lt;/strong&gt;; bound to the same physics laws. Lighter gases &amp;quot;rise up&amp;quot;, above heavier ones which &amp;quot;sink down&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Between all these, there's gravity, which attracts them all.&lt;/p&gt;&#xA;" OwnerUserId="22275" LastActivityDate="2021-04-13T13:39:18.407" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21089" PostTypeId="1" AcceptedAnswerId="21092" CreationDate="2021-04-13T14:08:24.160" Score="2" ViewCount="129" Body="&lt;p&gt;I hiked the Lanikai Pillbox trail (&lt;a href=&quot;https://www.google.com/maps/place/Lanikai+Pillbox/@21.3893391,-157.716528,16.75z/data=!4m13!1m7!3m6!1s0x7c0014f892682f7f:0xec50e2c96a16e2b1!2sLanikai+Beach!3b1!8m2!3d21.3925378!4d-157.7151208!3m4!1s0x7c0014f7ab4d2761:0xc586727ccfefbd4a!8m2!3d21.3855953!4d-157.7166534&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oahu, HI&lt;/a&gt;). I noticed eroded concentric rings in the igneous rock with a hard center. I'm unable to find the geologic cause of these rings. Are they Liesegang rings? There were several instances (~20) I observed on the hike.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OvPtt.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OvPtt.jpg&quot; alt=&quot;Concentric rings in igneous rock in Oahu, HI hike.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22276" LastEditorDisplayName="user20559" LastEditDate="2021-05-10T11:20:09.973" LastActivityDate="2021-05-10T11:20:09.973" Title="Are these igneous Liesegang rings on a popular Oahu, Hawaii hike?" Tags="|geology|petrology|igneous|weathering|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21090" PostTypeId="2" ParentId="21083" CreationDate="2021-04-13T14:18:34.423" Score="3" Body="&lt;p&gt;Carbon dioxide has the same components as an oxygen molecule, plus a carbon atom, so the forces that keep oxygen from escaping the atmosphere apply even more to CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The escape velocity of the Earth is about 11 km/s, and the speed of sound is 300 m/s. So a molecule would have to be traveling at more than Mach 30 to have escape velocity. That's not a complete answer (that would require discussing Boltzmann distributions and such), but it should be enough to give an intuitive idea why the Earth doesn't lose its atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="11501" LastActivityDate="2021-04-13T14:18:34.423" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21091" PostTypeId="2" ParentId="13449" CreationDate="2021-04-13T18:08:56.793" Score="0" Body="&lt;p&gt;Groundhog day doesn't have anything to do with science. It's based on a pagan festival called Imbolc. It's their traditional start of spring and known to Christians as Candlemas.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Imbolc&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Imbolc&lt;/a&gt;&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Groundhog_Day&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Groundhog_Day&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22228" LastActivityDate="2021-04-13T18:08:56.793" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21092" PostTypeId="2" ParentId="21089" CreationDate="2021-04-13T20:24:00.230" Score="2" Body="&lt;p&gt;Not knowing the setting and judging from the image alone in this trampled environment, I think we're looking at a form of chemical weathering called &amp;quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Spheroidal_weathering&quot; rel=&quot;nofollow noreferrer&quot;&gt;spheroidal weathering&lt;/a&gt;&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;The gist is this (from the linked wiki page):&#xA;Penetrating water alters the bed-rock &lt;a href=&quot;https://www.geo.fu-berlin.de/en/v/geolearning/mountain_building/weathering/weathering2/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;along cracks or joints&lt;/a&gt;, causing volume changes between altered and unaltered parts. These differences result in the formation of spheroidal layers that are removed by erosion (or trampling), leaving a central relatively unaltered boulder/pebble.&lt;/p&gt;&#xA;&lt;p&gt;Liesegang rings are somewhat enigmatic, not sure if the term is applicable here.&lt;/p&gt;&#xA;" OwnerDisplayName="user22279" LastEditorDisplayName="user22279" LastEditDate="2021-04-14T12:59:54.783" LastActivityDate="2021-04-14T12:59:54.783" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21093" PostTypeId="1" CreationDate="2021-04-13T21:29:12.660" Score="2" ViewCount="26" Body="&lt;p&gt;This was asked in aviation stack exchange and the best answer (credit:ymb1) was:&lt;/p&gt;&#xA;&lt;p&gt;The westerly index is the Trenberth Z1 index (Trenberth 1976), which is the departure of the monthly mean pressure difference between Auckland and Christchurch (near 44°S) from its mean over the 1961–90 period.&lt;/p&gt;&#xA;&lt;p&gt;Can anyone expand on that? And explain how it is calculated?&lt;/p&gt;&#xA;" OwnerUserId="22281" LastActivityDate="2021-04-13T21:29:12.660" Title="What is the westerly index?" Tags="|wind|pressure|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21094" PostTypeId="1" CreationDate="2021-04-13T21:35:23.320" Score="4" ViewCount="86" Body="&lt;p&gt;Coming from the aviation site: &lt;a href=&quot;https://aviation.stackexchange.com/q/86529/14897&quot;&gt;What is the westerly index?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The &lt;em&gt;westerly index&lt;/em&gt; is:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;... the Trenberth Z1 index (&lt;a href=&quot;https://scholar.google.com/scholar_lookup?title=Fluctuations%20and%20trends%20in%20indices%20of%20the%20Southern%20Hemisphere%20circulation.&amp;amp;author=K.%20E.%20Trenberth&amp;amp;publication_year=1976&amp;amp;volume=102&amp;amp;pages=65-75&quot; rel=&quot;nofollow noreferrer&quot;&gt;Trenberth 1976&lt;/a&gt;), which is the departure of the monthly mean pressure difference between Auckland and Christchurch (near 44°S) from its mean over the 1961–90 period.&lt;/p&gt;&#xA;&lt;p&gt;— &lt;a href=&quot;https://journals.ametsoc.org/view/journals/apme/46/5/jam2491.1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;journals.ametsoc.org&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Those two places are ~750 km apart (not a small distance), and &lt;a href=&quot;https://www.aviationweather.gov/metar/data?ids=nzaa,nzch&amp;amp;format=raw&amp;amp;hours=0&amp;amp;taf=off&amp;amp;layout=on&quot; rel=&quot;nofollow noreferrer&quot;&gt;judging by the METAR reports&lt;/a&gt;, the QNH difference in the past 72 hours varies from 4 to 7 millibars or so. Is that unusual? What's the significance of that index?&lt;/p&gt;&#xA;" OwnerUserId="13092" LastActivityDate="2021-04-13T21:35:23.320" Title="What does a change in the mean pressure across 750 km indicate/signify?" Tags="|meteorology|climate|barometric-pressure|pacific|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21096" PostTypeId="2" ParentId="21077" CreationDate="2021-04-14T01:56:54.557" Score="2" Body="&lt;h2&gt;We don't know, and that's why we have to develop it.&lt;/h2&gt;&#xA;&lt;p&gt;that's the thing about undeveloped sciences &lt;strong&gt;we don't know what many of the risks are&lt;/strong&gt;, Its a case of knowing what we don't know. Which is one big reason to develop it, so we don't cause harm accidentally.&lt;/p&gt;&#xA;&lt;p&gt;Lets be clear &lt;strong&gt;we already are geoengineering&lt;/strong&gt; right now, by driving cars, changing the landscape, polluting the air,  we are just doing it blind. We have to research things to understand the risks, and geoengineering has barely be scratched.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2021-04-14T01:56:54.557" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21098" PostTypeId="1" CreationDate="2021-04-13T16:16:02.983" Score="7" ViewCount="378" Body="&lt;p&gt;Not sure if here or physics is the best place for this question, but if there was a meteor that had gold in it, what happens to that metal during entry of the Earth's atmosphere?  Since gold melts at 1948° F (1046°C) and boils at 5378° F (2970°C), and Space.com says a meteor reaches about 3000° F (1650 °C) on average, even if that's just the surface temp, some gold would liquify (I think).  I'm guessing depending on the angle of entry, it could retain enough velocity to leave the atmosphere, but I think at least it some cases, it could rain down as either liquid or solid gold and would be gold meteorites.&lt;/p&gt;&#xA;" OwnerDisplayName="user22308" LastEditorUserId="6" LastEditDate="2021-04-21T19:10:43.897" LastActivityDate="2021-04-21T19:10:43.897" Title="Would a gold-containing meteor cause it to &quot;rain&quot; gold?" Tags="|meteorite|asteroids|" AnswerCount="2" CommentCount="19" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21099" PostTypeId="1" AcceptedAnswerId="21284" CreationDate="2021-04-14T16:53:20.413" Score="2" ViewCount="100" Body="&lt;p&gt;The inner core is solid only because of the very high pressure of the outer core and mantle &lt;em&gt;. Say, if the inner core moved a teeny tiny bit would some of it liquify and melt? Or does it stay solid?&lt;/em&gt;&#xA;Also if the Inner core bulged would a bump about 1/8 of the size of the mantle occur on the inner core because of space taken up?&lt;/p&gt;&#xA;" OwnerUserId="21926" LastEditorUserId="11430" LastEditDate="2021-05-09T04:42:06.737" LastActivityDate="2021-05-20T17:48:46.367" Title="What would happen if the inner core bulged and moved a tiny bit?" Tags="|geophysics|core|pressure|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21100" PostTypeId="1" AcceptedAnswerId="21108" CreationDate="2021-04-14T17:09:38.113" Score="2" ViewCount="192" Body="&lt;p&gt;I starting a weather project where I'm using ERA5 hourly dataset (ref: &lt;a href=&quot;https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-era5-single-levels?tab=form&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-era5-single-levels?tab=form&lt;/a&gt;). Using this dataset in python, I have now a dataframe as below.&lt;/p&gt;&#xA;&lt;p&gt;As you can see, for one State I have n observations considering latitude|longitude and Time of observation. So, now I would like to aggregate this dataset daily, considering Admin2 and Admin1, in order to have Max Temp, Min Temp and Total precipitation. Is there a right way to do this aggregation or is this simple the max / min values from 2m temp and sum of precipitation?&#xA;As you can see, by the content of my question, I'm not a meterologist. I'm just trying to build a reliable database for past historical weather data from some cities around the world.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hftyM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hftyM.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22289" LastActivityDate="2021-04-15T03:42:32.027" Title="What is the correct way to report historical daily Max / Min / Avg Temperature by City?" Tags="|temperature|data-analysis|database|era|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21101" PostTypeId="1" CreationDate="2021-04-14T17:51:51.827" Score="4" ViewCount="227" Body="&lt;p&gt;Sorry if this is the wrong place...&lt;/p&gt;&#xA;&lt;p&gt;I have been camping a lot recently and I couldn't help but notice some of the campgrounds I am in are acres and acres of mostly pine trees. These trees have very little greenery on them as opposed to most other species. Does that make, say an Oak a better tree for cleaning the air and/or as a carbon sink than a pine?  If I wanted to plant a native species of tree on my land with the intent of helping to clean the air the most, is there research that exist for that? Or is there a reasoning of 10 pines in the same space of one oak is better?&lt;/p&gt;&#xA;" OwnerUserId="22291" LastEditorUserId="6298" LastEditDate="2021-12-06T14:50:39.740" LastActivityDate="2021-12-06T16:14:28.383" Title="Which types of trees clean the air best?" Tags="|climate-change|air-quality|plant|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21102" PostTypeId="2" ParentId="13449" CreationDate="2021-04-14T18:30:48.347" Score="2" Body="&lt;p&gt;It is a myth. To say that it is unscientific is perhaps not the best phrasing, but &lt;a href=&quot;https://www.livescience.com/32974-punxsutawney-phil-weather-prediction-accuracy.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Groundhog day isn't the most accurate prognostication method around&lt;/a&gt;. For something to be scientific, &lt;a href=&quot;https://www.livescience.com/20896-science-scientific-method.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;it needs to follow the scientific method&lt;/a&gt;. Given that Groundhog day follows the myth that:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A groundhog that sees it's shadow will become frightened, seeking shelter from the upcoming chill of 6 more weeks of winter, or&lt;/li&gt;&#xA;&lt;li&gt;A groundhog that doesn't see it's shadow is certain that a chill is not on its way&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;, the implication &lt;a href=&quot;https://www.groundhog.org/legend-and-lore&quot; rel=&quot;nofollow noreferrer&quot;&gt;derived from a poem&lt;/a&gt; being that nice weather now means bad weather later and vice-versa. Without defining 'winter' or 'spring' I question the testability of the hypothesis. In reality, &lt;a href=&quot;https://www.timeanddate.com/date/durationresult.html?m1=02&amp;amp;d1=02&amp;amp;y1=2021&amp;amp;m2=03&amp;amp;d2=20&amp;amp;y2=2021&quot; rel=&quot;nofollow noreferrer&quot;&gt;astronomical spring occurs 6 weeks and 4 days after Groundhog day&lt;/a&gt;, making the distinction between the groundhog's &amp;quot;definition&amp;quot; of spring entirely subjective. But translating a subjective metric into an objective criteria, &lt;a href=&quot;https://en.wikipedia.org/wiki/Farmers%27_Almanac#Accuracy&quot; rel=&quot;nofollow noreferrer&quot;&gt;it is less accurate than the Farmer's Almanac of 50%&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;If you want a more likely explanation on why a groundhog might behave the way it does, one need not look much farther than a picture from Punxsutawney, PA on groundhog day:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wkrGo.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wkrGo.jpg&quot; alt=&quot;Groundhog day, 2020 in Punxatawney PA, source: PennLive.com&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Given such a crowd, will an animal react more about the crowd or the upcoming weather? My guess is that if you saw such a crazed crowd show up to your house at 7:25 AM, you would want to crawl into a hole too. A groundhog must go into it's hole at some point, and I don't know of a part of the myth that says that the groundhog must immediately go back into its hole. Doing a groundhog day tradition with so much festivity, scientifically (not necessarily rationally though), be a contaminating factor to any sort of experiment. That is, even slight deviations in how such a thing is conducted (and given that groundhogs like Phil basically &lt;a href=&quot;https://www.washingtonpost.com/nation/2020/01/29/groundhog-peta-punxsutawney/&quot; rel=&quot;nofollow noreferrer&quot;&gt;live like royalty in comparison to groundhogs in their natural state&lt;/a&gt;) make any rigorous evaluation of Phil's prognostication ability questionable.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-04-14T18:30:48.347" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21103" PostTypeId="2" ParentId="21098" CreationDate="2021-04-14T18:46:19.037" Score="4" Body="&lt;p&gt;As it melted, it would be broken up into a spray or even a mist by the airstream. The droplets would quickly slow down to their terminal velocity and solidify, so you would get a fine gold dust imperceptibly falling over a wide area.&lt;/p&gt;&#xA;&lt;p&gt;I am basing this on my admittedly incomplete understanding of meteors that do not contain gold. When the one in Russia some years ago exploded, it didn't &lt;em&gt;vaporize&lt;/em&gt;, but only so many pieces were found.&lt;/p&gt;&#xA;" OwnerUserId="22292" LastActivityDate="2021-04-14T18:46:19.037" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21104" PostTypeId="2" ParentId="21101" CreationDate="2021-04-14T20:04:12.567" Score="3" Body="&lt;p&gt;Evergreen trees grow faster than most hardwood deciduous trees, so their absorption and oxygen emission is greater.&lt;/p&gt;&#xA;&lt;p&gt;Note that trees do not &amp;quot;clean&amp;quot; air. Plants emit oxygen which is why air in a house with lots of plants will seem more fresh. In the global environment algae and other primitive organics are primarily responsible for converting CO&lt;sub&gt;2&lt;/sub&gt; to oxygen, not trees.&lt;/p&gt;&#xA;&lt;p&gt;Particulate pollutants and some compounds with good water solubility, like sulfur dioxide and ammonia, are removed from air by moisture which condenses and falls to earth bringing the particulates with it.&lt;/p&gt;&#xA;" OwnerUserId="2491" LastEditorUserId="2470" LastEditDate="2021-04-15T04:50:14.290" LastActivityDate="2021-04-15T04:50:14.290" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21105" PostTypeId="2" ParentId="21100" CreationDate="2021-04-14T20:16:57.767" Score="1" Body="&lt;p&gt;Yes, daily minima, maxima and precipitation totals are calculated simply as you suggested in your question. Take care that there aren't missing values,, but that's more of an issue calculating means. Also check whether the reported values for precipitation are in fact a null value, it's unlikely that it could be measured in such small units.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2021-04-14T20:16:57.767" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21106" PostTypeId="2" ParentId="12464" CreationDate="2021-04-15T01:24:06.380" Score="-1" Body="&lt;p&gt;Unless your house has a comprehensive HVAC system with air filtration the air inside the house will be just a polluted as the air outside of it.&lt;/p&gt;&#xA;&lt;p&gt;Breathing rarified smoke is not dangerous. Remember that before ovens and stoves people heated their houses with fireplaces and breathed smoke all day long, every day--way more smoke than you would ever be exposed to by a distant forest fire.&lt;/p&gt;&#xA;&lt;p&gt;The air inside your house is probably way more polluted than the air outside of it because of all the toxic shit you bring into the house and release, such as: bathroom cleaners, window cleaners, &amp;quot;air fresheners&amp;quot;, toilet cleaners, waxes, polishes, nail polish, perfume, deodorants, the car, hair spray, etc. Also, there are lots of things in your house that outgas highly toxic, carcinogenic substances including: computers, phones, audio equipment, anything rubber, anything with volatile oils and lubricants like motors, anything made out of fabric treated with fire retardent (upholstery, clothing, rugs, curtains, etc). Then, of course, if you have a modern house it is made of drywall, so you are constantly breathing gypsum dust (calcium sulfate), and if the house is insulated, then you are also  breathing particles of fiberglass. Get the picture?&lt;/p&gt;&#xA;&lt;p&gt;The government tells you to stay inside because they want to control you.&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2021-04-15T01:24:06.380" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21107" PostTypeId="1" CreationDate="2021-04-15T02:11:50.303" Score="4" ViewCount="264" Body="&lt;p&gt;There seems to be a general consensus that the Earth is in radiative imbalance, i.e., it is absorbing more solar energy than it radiates.  One figure I've seen bandied about for this imbalance is that it is about +0.6 W/m&lt;sup&gt;2&lt;/sup&gt; averaged over Earth's surface.&lt;/p&gt;&#xA;&lt;p&gt;We also have a fairly good grasp of the various radiative forcings influencing Earth's climate, with a sum total of something like 2.2 watts per square meter.  These forcings are measured relative to 1750, i.e., the Earth is effectively receiving 2.2 W/m&lt;sup&gt;2&lt;/sup&gt; more than it was in 1750 due to these effects.&lt;/p&gt;&#xA;&lt;p&gt;Does this mean that the Earth was losing net energy in 1750, at a rate of 0.6 W/m&lt;sup&gt;2&lt;/sup&gt; - 2.2 W/m&lt;sup&gt;2&lt;/sup&gt; ≈ -1.6 W/m&lt;sup&gt;2&lt;/sup&gt;?  If so, does this imply that the Earth was not in radiative equilibrium in pre-industrial times?  Was it cooling off?&lt;/p&gt;&#xA;&lt;p&gt;Or have I misunderstood some important ideas in here, and this this is too simplistic of a way to look at things?&lt;/p&gt;&#xA;" OwnerUserId="4837" LastActivityDate="2021-04-17T05:13:05.733" Title="Connection between radiative imbalance and radiative forcing" Tags="|climate-change|radiative-transfer|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21108" PostTypeId="2" ParentId="21100" CreationDate="2021-04-15T03:42:32.027" Score="1" Body="&lt;p&gt;I don't know if ERA5 data has some weird format, as I'm really not familiar with working with such data directly.  But it's vital to realize that the greatest hourly temp is rarely the daily max, and the same idea with mins.  &lt;a href=&quot;https://w1.weather.gov/data/obhistory/KMCO.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Orlando's&lt;/a&gt; data today:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/h1OR9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/h1OR9.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The max today was 87°F and the min 63°F (found from this using the 6 hour max\mins... there can be rare issues with this when those don't fall at midnight... station reports or metars give 24 hour max\min midnight to midnight... though it's only an issue when a max or min is near midnight, which is rare, typically only during airmass changes)&lt;/p&gt;&#xA;&lt;p&gt;Whereas the top hourly was 86°F and the bottom one was 65°F.  And that's a fairly typical thing to occur... they only match when the extreme temperatures happen to occur near the end of the hour (values are typically taken about 7 minutes before the hour in the US, and I believe that standard varies a bit internationally)&lt;/p&gt;&#xA;&lt;p&gt;So I'd certainly question any work that tried to derive daily actual max\min values or compare to them using such hourly results, unless it turns out ERA5 does something unique.  It's tough to imagine it's valid given it you only get one hourly value.&lt;/p&gt;&#xA;&lt;p&gt;Precipitation measurements on the other hand are over a time period, so those values should be hourly values, and summing them should give the results for the day.&lt;/p&gt;&#xA;&lt;p&gt;When it comes to temperature (assuming ERA5 isn't somehow strangely taking care of the discontinuity), you could try to apply some sort of rough multiplier to give a very crude better guess... but thinking you won't be able to get legitimate daily max\mins without looking for actual site data, which are for example available &lt;a href=&quot;https://sercc.com/noaa-online-weather/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; for basic US historic or recent data searches, or at &lt;a href=&quot;https://www.ncdc.noaa.gov/cdo-web/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCDC&lt;/a&gt;.  Of course those are only going to work for places they have observation sites.  But it doesn't seem that you can directly compare the ERA5 maxima results to actual station maxima easily.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2021-04-15T03:42:32.027" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21109" PostTypeId="2" ParentId="21098" CreationDate="2021-04-15T08:54:17.143" Score="3" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Would a gold-containing meteor cause it to “rain” gold?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;h2&gt;No.&lt;/h2&gt;&#xA;&lt;p&gt;First, it is a bit unclear what do you mean by &amp;quot;gold-containing meteor&amp;quot;. All solar system bodies have gold, the question is how much. For this answer I will assume that you mean a meteorite with chunks of visible gold nuggets in it, nothing that this is a hypothetical concept as no such meteorites are known or expected.&lt;/p&gt;&#xA;&lt;p&gt;Meteors, when in space, are very very &lt;strong&gt;very &lt;em&gt;very&lt;/em&gt;&lt;/strong&gt; cold. Their travel duration in Earth's atmosphere is very short, just a couple of seconds. Actual melting only occurs at the very most outer layer of the meteorite. This is not sufficient to heat up the interior of the meteorite to any significant degree. In fact, some meteorite falls have found to have frost on them when found soon after landing, because they condense the moisture in the air around them! Some meteorites still contain organic material which would be destroyed at much lower temperature than the melting point of gold.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-04-15T08:54:17.143" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="21110" PostTypeId="1" CreationDate="2021-04-15T11:54:40.923" Score="2" ViewCount="67" Body="&lt;p&gt;I find it difficult to teach college students about using the triangular facet on remote sensing images to judge the dip direction of sedimentary formations. Is there any intuitive way that can help?&lt;/p&gt;&#xA;" OwnerUserId="11924" LastEditorUserId="2470" LastEditDate="2021-04-16T05:23:29.377" LastActivityDate="2021-04-16T05:23:29.377" Title="Is there any intuitive and easily understandable way to help students understand the triangular facet of outcropted stratigraphy?" Tags="|geology|remote-sensing|structural-geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21111" PostTypeId="2" ParentId="19945" CreationDate="2021-04-15T14:26:25.747" Score="1" Body="&lt;p&gt;&lt;a href=&quot;https://www.wiley.com/en-gb/The+Warming+Papers%3A+The+Scientific+Foundation+for+the+Climate+Change+Forecast-p-9781405196161&quot; rel=&quot;nofollow noreferrer&quot;&gt;&amp;quot;The Warming Papers&amp;quot;&lt;/a&gt; edited by David Archer and Raymond Pierrehumbert is good for historical context.  It is basically a collection of classic journal papers, starting with Fourier and Tyndall, but it also covers key papers on climate modelling, ice cores and the carbon cycle etc.&lt;/p&gt;&#xA;" OwnerUserId="624" LastActivityDate="2021-04-15T14:26:25.747" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21112" PostTypeId="1" AcceptedAnswerId="21122" CreationDate="2021-04-15T17:38:24.187" Score="2" ViewCount="302" Body="&lt;p&gt;I am interested in knowing what kind of fossils we would find if we were to drill horizontally through the mountain and what we would find if we were to drill vertically. Would we find anything interesting other than the fossils?&lt;/p&gt;&#xA;" OwnerUserId="22302" LastActivityDate="2021-04-17T19:09:16.363" Title="What would people drilling through Mount Everest find?" Tags="|fossils|drilling|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="21113" PostTypeId="2" ParentId="21112" CreationDate="2021-04-15T17:55:36.740" Score="0" Body="&lt;p&gt;Mount Everest is a Mountain Made from the Indian Subcontinent Colliding into the Asian Continental Plates, You are most likely NOT to find fossils because there was not a mount Everest during the Dinosaurs but Maybe some fossils could have gotten lifted by the collision but would be torn apart and scattered. according to &lt;a href=&quot;http://pubs.usgs.gov/gip/dynamic/himalaya.html#:%7E:text=This%20immense%20mountain%20range%20began,be%20subducted%20under%20the%20other.&quot; rel=&quot;nofollow noreferrer&quot;&gt;[Source]&lt;/a&gt;, The Himilayas formed 40 and 50 Million years ago, &lt;em&gt;Which was around the end of the cretaceous period, which ended some 65 million years ago.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;You will find Material and metals brought up from the bedrock of the Continental Crust, The Himalayas would eventually start getting weathered which would expose some metals.&lt;/p&gt;&#xA;" OwnerUserId="21926" LastEditorUserId="21926" LastEditDate="2021-04-15T18:48:24.483" LastActivityDate="2021-04-15T18:48:24.483" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21114" PostTypeId="1" CreationDate="2021-04-15T19:51:09.697" Score="1" ViewCount="65" Body="&lt;p&gt;Temperatures are 5-7 degrees Celsius above average in southwestern British Columbia, and it's surreal for it to be so warm and sunny when the deciduous trees are still mostly barren.&lt;/p&gt;&#xA;" OwnerUserId="6816" LastEditorUserId="2470" LastEditDate="2021-04-16T05:29:39.933" LastActivityDate="2021-04-16T05:29:39.933" Title="Why is it so warm in the Pacific Northwest of North America right now - mid April 2021?" Tags="|meteorology|weather-forecasting|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="21115" PostTypeId="2" ParentId="21112" CreationDate="2021-04-15T20:35:01.150" Score="3" Body="&lt;p&gt;The summit of the mountain is made up of 400 million year old sedimentary rocks laid down long before the uplift 50 million years ago.  These rocks contain marine fossils including Trilobites and Crinoids. If you drilled down from the summit you would then encounter older metamorphic rocks,  the upper parts of which contain traces of fossils, and then in to gneisses and granites.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://all-geo.org/metageologist/2012/06/the-geology-of-mount-everest/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://all-geo.org/metageologist/2012/06/the-geology-of-mount-everest/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21672" LastEditorUserId="21672" LastEditDate="2021-04-16T14:15:14.630" LastActivityDate="2021-04-16T14:15:14.630" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21117" PostTypeId="1" CreationDate="2021-04-15T21:19:08.377" Score="1" ViewCount="30" Body="&lt;p&gt;My understanding is that positive CG flashes are more common on the leading edge or tail end of a storm, and can be associated with weakening storms. Shouldn't the most powerful lightning strikes (+CG flashes can have a peak current of 500 kA) occur in the most powerful part of the storm, and signify a strengthening storm?&lt;/p&gt;&#xA;&lt;p&gt;The only exception I've read in the literature was the Spencer, SD F4 on May 30, 1998. The precip core of the supercell spit out +CG flashes as the tornado levelled the town.&lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2021-04-15T21:19:08.377" Title="Why aren't positive cloud-to-ground lightning strikes associated with the precipitation core of a storm?" Tags="|lightning|thunderstorm|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21118" PostTypeId="2" ParentId="21067" CreationDate="2021-04-16T00:37:44.887" Score="3" Body="&lt;p&gt;Nothing really prevents water from existing deep inside Earth.  We have direct evidence that it does, even in the mantle.&lt;/p&gt;&#xA;&lt;p&gt;Evidence for such water may be found in Ice VII inclusions in diamonds[&lt;a href=&quot;https://science.sciencemag.org/content/359/6380/1136&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;].  Because of their great mechanical strength, diamonds formed in the mantle retain GPa-level pressure within their lattice, so when they come to the surface and cool off any water trapped in them condenses into the high-pressure Ice VII phase instead of the ordinary Ice I&lt;span class=&quot;math-container&quot;&gt;$_{\text{h}}$&lt;/span&gt; or liquid phase.&lt;/p&gt;&#xA;&lt;p&gt;Such a phase with the formula &lt;span class=&quot;math-container&quot;&gt;$\text{H}_2\text{O}$&lt;/span&gt; would have to come from uncombined water as distinct from hydroxyl groups in rocky matter.  From the abstract:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The [Ice VII] inclusions suggest that local aqueous pockets form at the transition zone boundary [between the upper mantle and lower mantle] owing to the release of chemically bound water as rock cycles in and out of this region.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://space.stackexchange.com/a/33570/28871&quot;&gt;This answer&lt;/a&gt; from Space Exploration Stack Exchange describes the finding of diamond-borne Ice VII in more detail and suggests the possibility of finding other high-pressure ices in outer-planet moons through seismic measurements.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;1.&#xA;O. Tschauner, S. Huang, E. Greenberg, V. B. Prakapenka, C. Ma, G. R. Rossman, A. H. Shen, D. Zhang, M. Newville, A. Lanzirotti, K. Tait, &amp;quot;Ice-VII inclusions in diamonds: Evidence for aqueous fluid in Earth’s deep mantle&amp;quot;, &lt;em&gt;Science&lt;/em&gt;  09 Mar 2018: &lt;strong&gt;359&lt;/strong&gt;, Issue 6380, pp. 1136-1139. &lt;a href=&quot;https://doi.org/10.1126/science.aao3030&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1126/science.aao3030&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2023-01-25T23:36:09.830" LastActivityDate="2023-01-25T23:36:09.830" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21119" PostTypeId="2" ParentId="21110" CreationDate="2021-04-16T01:34:44.597" Score="3" Body="&lt;p&gt;This is a tale of two three dimensional coordinate systems. You may need to take a bit of a side track if your students are not already familiar with the concepts of three dimensional coordinate systems, three dimensional vectors, the three dimensional dot and cross products, and transformations between coordinate systems. The image below portrays two such coordinate systems, with axes in blue and red,&#xA;&lt;a href=&quot;https://i.stack.imgur.com/wBsBC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wBsBC.png&quot; alt=&quot;Two sets of three dimensional orthogonal axes&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I'll denote one of those coordinate systems as the East, North, Up coordinate system (ENU for short), with unit vectors &lt;span class=&quot;math-container&quot;&gt;$\hat E$&lt;/span&gt; (East), &lt;span class=&quot;math-container&quot;&gt;$\hat N$&lt;/span&gt; (North), and &lt;span class=&quot;math-container&quot;&gt;$\hat U$&lt;/span&gt; (Up), and the other as the dip, strike and outward normal coordinate system (dsn for short), with unit vectors &lt;span class=&quot;math-container&quot;&gt;$\hat d$&lt;/span&gt; (dip), &lt;span class=&quot;math-container&quot;&gt;$\hat s$&lt;/span&gt; (strike), and &lt;span class=&quot;math-container&quot;&gt;$\hat n$&lt;/span&gt; ((outward) normal). In terms of the above diagram, imagine the trio of blue vectors corresponding to East, North, and Up while the trio of red vectors corresponding to dip, strike, and (outward) normal. As an instructor, you might well want to create a better diagram, with labels.&lt;/p&gt;&#xA;&lt;p&gt;There are singularity issues with both of these sets of coordinate systems. East/North/Up doesn't make sense at the Earth's poles as all horizontal directions are south at the North Pole and north at the South Pole. The dip/strike/normal doesn't make sense wherever the surface is flat. I'll ignore those issues. (Bonus question for your students: Address those singularities.)&lt;/p&gt;&#xA;&lt;p&gt;One way to define local ENU coordinate system for a point on the surface of the Earth is to use the Earth's reference ellipsoid. The &amp;quot;up&amp;quot; unit vector is normal to the ellipsoid, with &amp;quot;up&amp;quot; pointing outward. The east unit vector is orthogonal to the &lt;span class=&quot;math-container&quot;&gt;$\hat U$&lt;/span&gt; unit vector and the Earth's rotation axis. Use the cross product and divide by the norm. The north unit vector is the cross product of the up and east unit vectors.&lt;/p&gt;&#xA;&lt;p&gt;Regarding the dip/strike/normal coordinate system, one direction, the outward normal, can be determined from the coordinates of the three points in a triangle in a vector-based triangular network digital elevation model. The coordinates of the three points in a triangle (&lt;span class=&quot;math-container&quot;&gt;$\vec A$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\vec B$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\vec C$&lt;/span&gt;) are supposed to be arranged such that &lt;span class=&quot;math-container&quot;&gt;$(\vec B - \vec A)\times (\vec C - \vec B)$&lt;/span&gt; points outward. This points in the direction of &lt;span class=&quot;math-container&quot;&gt;$\hat n$&lt;/span&gt;: &lt;span class=&quot;math-container&quot;&gt;$\hat n = \frac{(\vec B - \vec A)\times (\vec C - \vec B)}{||(\vec B - \vec A)\times (\vec C - \vec B)||}$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Aside: This is not always the case; there are DEMs that do not follow this rule. Those are DEMs one should toss in the nearest digital trashcan.)There are also some DEMs that do follow this rule but occasionally have triangles whose outward normal has a downward rather than upward component. An example is an extremely detailed DEM that models not only the topside but also the underside of an overhang. Satellite-based DEMS typically don't do this as satellites cannot see the underside of an overhang. (Extra credit: Have your students address such cases!)&lt;/p&gt;&#xA;&lt;p&gt;We're looking for &lt;span class=&quot;math-container&quot;&gt;$\hat s$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\hat d$&lt;/span&gt;, the unit vectors that point in the strike and dip direction. Both of these vectors lie in the plane of the triangle formed by &lt;span class=&quot;math-container&quot;&gt;$\vec A$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\vec B$&lt;/span&gt;, and &lt;span class=&quot;math-container&quot;&gt;$\vec C$&lt;/span&gt;. This means that both &lt;span class=&quot;math-container&quot;&gt;$\hat s$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\hat d$&lt;/span&gt; are normal to the outward normal &lt;span class=&quot;math-container&quot;&gt;$\hat o$&lt;/span&gt;. The strike vector is horizontal, which means that it is also normal to the unit upward normal. To find &lt;span class=&quot;math-container&quot;&gt;$\hat s$&lt;/span&gt;, compute the cross product of &lt;span class=&quot;math-container&quot;&gt;$\hat U$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\hat n$&lt;/span&gt; and normalize. (Note: Normalization is impossible if &lt;span class=&quot;math-container&quot;&gt;$\hat U \times \hat n \equiv 0$&lt;/span&gt;. This only happens if &lt;span class=&quot;math-container&quot;&gt;$\hat n$&lt;/span&gt; is parallel or antiparallel to &lt;span class=&quot;math-container&quot;&gt;$\hat U$&lt;/span&gt;, in which case strike and dip are not well-defined.) Finally, the dip unit vector, which is what we're after, is the cross product of the strike and outward normal unit vectors: &lt;span class=&quot;math-container&quot;&gt;$\hat d = \vec s \times \vec n$&lt;/span&gt;. Bonus: Ask your students to show that if &lt;span class=&quot;math-container&quot;&gt;$\hat d$&lt;/span&gt; exists, it always has a downward component.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2021-04-16T01:34:44.597" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21122" PostTypeId="2" ParentId="21112" CreationDate="2021-04-16T10:43:22.490" Score="2" Body="&lt;p&gt;Looks like some basic hints are necessary (as a complement to @AndyM's answer):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;stratigraphy &lt;em&gt;usually&lt;/em&gt; goes from younger to older when going down.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;there'll be little chance to find any macrofossils in rocks that formed before sufficiently complex life was around.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;there'll be little chance to find fossils in rocks that underwent metamorphism, that is have been in pressure/temperature regimes that aren't conducive for their preservation, even if they initially were present in the pre existing rocks.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;'trace fossils' are not small remains of fossils but fossilized traces ('footprints'). Very rare thing.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;it may be possible to find fossils in overlaying, younger sediments that formed during or after the uplift or were trapped or transported in depressions, but that's not the point of the question I think.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;So, below the uppermost formations around the summit you'll likely find nothing of interest &lt;em&gt;in the sense of the question&lt;/em&gt; when drilling down.&lt;/p&gt;&#xA;&lt;p&gt;Will provide sources on &lt;em&gt;specificically focussed&lt;/em&gt; request, but this isn't top notch geoscience.&lt;/p&gt;&#xA;" OwnerDisplayName="user22279" LastEditorDisplayName="user22279" LastEditDate="2021-04-17T19:09:16.363" LastActivityDate="2021-04-17T19:09:16.363" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="21123" PostTypeId="1" AcceptedAnswerId="21125" CreationDate="2021-04-16T12:16:59.117" Score="4" ViewCount="1863" Body="&lt;p&gt;What will happen if the Indian Plate is done sliding under the Eurasian plate? I hypothesied some possible answers. Tell me the answer and if my hypothesis is not correct.&lt;/p&gt;&#xA;&lt;p&gt;Most likely to least.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;It will become part of the Eurasian Plate?&#xA;It will slide back out of Siberia?&#xA;It will get pushed into the mantle?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I know it is funny to think that the Indian Plate would find its way out of Siberia. I would also want to know what would happen to Mount Everest and the Himalayas.&lt;/p&gt;&#xA;" OwnerUserId="21926" LastEditorDisplayName="user20559" LastEditDate="2021-04-16T13:38:57.513" LastActivityDate="2021-04-17T05:42:59.437" Title="What will happen to the Indian plate after it slides under the Eurasian Plate?" Tags="|plate-tectonics|mountains|tectonics|mantle|erosion|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21125" PostTypeId="2" ParentId="21123" CreationDate="2021-04-16T15:56:30.100" Score="10" Body="&lt;p&gt;It is a continent-continent collision following subduction, no subduction is taking place at the moment. The ocean floor that was attached to it has vanished into the mantle or got wedged into the thickened crust. The collision builds up immense stress, resulting in deformation, faulting, folding, crustal shortening and uplift of the Tibetan plateau.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.files.ethz.ch/structuralgeology/jpb/files/English/Asiaeng.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.files.ethz.ch/structuralgeology/jpb/files/English/Asiaeng.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;Will it become part of the Eurasian Plate?&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;That's a question of definition of plate boundaries, fault lines, sutures ...&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;Will it slide back out of Siberia?&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Of course not. How could rocks even be preserved in such a process? In the process of shortening the crust is near completely consumed.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;Will it get pushed into the mantle?&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;No. Continental crust doesn't subduct. Both sides have approximately equal density and the mantle is much denser, so they just push and shove each other. Maybe parts get pushed to greater depths (~100km) in the dynamic process and exhumed again. Shortening will continue, uplift, faulting, folding and erosion in equilibrium, and when and where uplift stops erosion will take over.&lt;/p&gt;&#xA;&lt;p&gt;Afterwards there may probably be something like the Appalachians, an older result of a continent-continent collision and a very thick continental crust. Pop-science link depicting the principle: &lt;a href=&quot;https://www.nps.gov/subjects/geology/plate-tectonics-collisional-mountain-ranges.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nps.gov/subjects/geology/plate-tectonics-collisional-mountain-ranges.htm&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user22279" LastEditorUserId="2470" LastEditDate="2021-04-17T05:42:59.437" LastActivityDate="2021-04-17T05:42:59.437" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21126" PostTypeId="2" ParentId="21107" CreationDate="2021-04-16T15:58:31.053" Score="4" Body="&lt;p&gt;That +2.2 W/m&lt;sup&gt;2&lt;/sup&gt; is the effective radiative forcing, which is the difference in net top of atmosphere radiation in response to a changed set of conditions (e.g., greenhouse gas and aerosol concentrations, land use) after allowing fast system feedbacks to equilibrate (e.g., tropospheric humidity, stratospheric cooling) but not allowing for slow system feedbacks (ocean heat uptake, land- and sea-ice change).  That latter point is important because relatively little energy is stored in the atmosphere and land, so it’s the slow components that would adjust the system state to remove any net radiative imbalance.&lt;/p&gt;&#xA;&lt;p&gt;But note that it’s a theoretical, diagnostic property of the system; +2.2 W/m&lt;sup&gt;2&lt;/sup&gt; is not an energy imbalance that was ever actually expressed between the pre-industrial period and the present.  In reality, the forcing conditions and radiation imbalance occurred gradually, and the system responded gradually along with them, mainly by storing heat in the ocean and increasing the ocean surface temperature.  That has kept the expressed, measurable imbalance down to much lower values, giving us the +0.6 W/m&lt;sup&gt;2&lt;/sup&gt; that we have today.&lt;/p&gt;&#xA;&lt;p&gt;As for the pre-industrial imbalance, well, to quote &lt;a href=&quot;https://www.nature.com/articles/s41558-020-0696-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Andrews and Forster (2020)&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Since heat uptake was not observed in the nineteenth century, climate and energy balance models must be used to infer the pre-industrial energy imbalance. Forster summarized this to be around 0.10 W/m&lt;sup&gt;2&lt;/sup&gt; …&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;My experience from climate models is that 0.1 W/m&lt;sup&gt;2&lt;/sup&gt; is the typical variability in the decadal mean radiation balance in pre-industrial control simulations, so that observed estimate is probably not distinguishable from noise for a system that’s basically in radiative balance.  In the absence of any solid evidence to the contrary, we normally use a target of radiative balance and no drift in long term model state when spinning-up pre-industrial model climates.&lt;/p&gt;&#xA;" OwnerUserId="106" LastEditorUserId="2470" LastEditDate="2021-04-17T05:13:05.733" LastActivityDate="2021-04-17T05:13:05.733" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21127" PostTypeId="2" ParentId="21067" CreationDate="2021-04-17T13:52:41.807" Score="4" Body="&lt;p&gt;There are two reasons for this surprising finding:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Compaction. Once you have high pressures at depth, the less dense material goes up. Take a bucket of water, put sand in it, and squeeze the sand really hard. Water goes up. Then, you'd expect no water at depth of several kilometres.&lt;/li&gt;&#xA;&lt;li&gt;Even if you somehow had free water at these depths, the expectation is that they would form hydrous but solid minerals. For example, adding water to diopside, enstatite, and quartz leads to the formation of hydrous, but solid, tremolite:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\ce{2CaMgSi2O6 + 3MgSiO3 + SiO2 + H2O = Ca2Mg5Si8O22(OH)2}$$&lt;/span&gt;&#xA;or, adding water to quartz and corundum leads to the formation of kaolinite:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\ce{Al2O3 + 2SiO2 + 2H2O = Al2Si2O5(OH)4}$$&lt;/span&gt;&#xA;Increasing pressure leads to the equilibrium in these reactions shifting to the products, i.e. the solid hydrous phases without any free water.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;As to why the water was actually found there, there's still some debate in the scientific community. One of the explanations (&amp;quot;&lt;em&gt;...must have come from deep-crust minerals and had been unable to reach the surface because of a layer of impermeable rock&lt;/em&gt;&amp;quot;) is definitely reasonable. The other (&amp;quot;&lt;em&gt;scientists theorize that the water is comprised of hydrogen and oxygen atoms which were squeezed out of the surrounding rocks due to the incredible pressure.&lt;/em&gt;&amp;quot;) is probably incorrect.&lt;/p&gt;&#xA;&lt;p&gt;This (paywalled) paper provides an overview in a very accessible language: &lt;a href=&quot;https://doi.org/10.2138/gselements.16.6.381&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.2138/gselements.16.6.381&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-04-17T13:52:41.807" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21128" PostTypeId="1" CreationDate="2021-04-17T14:51:18.127" Score="4" ViewCount="842" Body="&lt;p&gt;Here I have a remote sensing dataset with many bands (e.g., blue, green, red, ...), and I use the blue, green and red bands to get a true color image. I want to know if I can get a panchromatic band based on this true color image?&lt;/p&gt;&#xA;&lt;p&gt;I guess it can be done by displaying the true color image as a grayscale image, then this grayscale image can be seen as a panchromatic image. Or I can convert the RGB format image to HIS format, then the insensity component can be seen as the panchromatic image. I am not sure whether it is right.&lt;/p&gt;&#xA;" OwnerUserId="11924" LastEditorUserId="725" LastEditDate="2022-01-14T03:10:27.787" LastActivityDate="2022-01-14T03:10:27.787" Title="Can I regard the grayscale of a RGB color image as a panchromatic image?" Tags="|geology|geography|remote-sensing|software|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21129" PostTypeId="1" AcceptedAnswerId="21131" CreationDate="2021-04-17T17:10:25.120" Score="3" ViewCount="511" Body="&lt;p&gt;My father, in his younger years, was a stone mason in Cincinnati Ohio. A couple of decades ago he was building a wall of some kind. He would fetch rock from a creek bed, haul it to the construction site, then shape it with what he calls a brick hammer.&lt;/p&gt;&#xA;&lt;p&gt;After giving one rock a good whack, he found that it contained a smooth gray stone about the size of a child's fist. One side of the stone is a little darker than the other. When cracked open the stone appears fairly homogeneous.&lt;/p&gt;&#xA;&lt;p&gt;How did this stone find its way inside the larger rock?&lt;/p&gt;&#xA;&lt;p&gt;EDIT: Removed my speculation (cited by one answer) and other clutter. Added example of stone used for the wall.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xkrpX.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xkrpXm.jpg&quot; alt=&quot;Whole Rock&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/i1fds.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/i1fdsm.jpg&quot; alt=&quot;Cracked Rock&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/e4CbB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/e4CbB.jpg&quot; alt=&quot;Wall Example&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(click to enlarge)&lt;/p&gt;&#xA;" OwnerUserId="22313" LastEditorDisplayName="user20559" LastEditDate="2021-05-10T11:21:16.127" LastActivityDate="2021-05-10T11:21:16.127" Title="How did this stone become encased within different rock?" Tags="|geology|rocks|petrology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21130" PostTypeId="2" ParentId="17574" CreationDate="2021-04-17T21:51:57.613" Score="3" Body="&lt;p&gt;The law that governs the pressure of gas &lt;em&gt;at equilibrium&lt;/em&gt; over a dissolved liquid is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Henry%27s_law#:%7E:text=In%20physical%20chemistry%2C%20Henry%27s%20law,is%20called%20Henry%27s%20law%20constant.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Henry's Law.&lt;/a&gt; Note, the equilibrium assumption, as there is some time dependence. That is, if you start with no dissolved gas in pure water, then in a relatively short amount of time, the amount of dissolved gas will be less than equilibrium.&lt;/p&gt;&#xA;&lt;p&gt;Let's talk in abstractions. &lt;a href=&quot;https://en.wikipedia.org/wiki/Henry%27s_law#Temperature_dependence&quot; rel=&quot;nofollow noreferrer&quot;&gt;Henry's law's temperature dependence&lt;/a&gt; resembles the &lt;a href=&quot;https://en.wikipedia.org/wiki/Clausius%E2%80%93Clapeyron_relation#Ideal_gas_approximation_at_low_temperatures&quot; rel=&quot;nofollow noreferrer&quot;&gt;Clausius-Clapeyeron equation&lt;/a&gt;, so we can draw some parallels. From the Wikipedia link, for a given gas, the Henry's law constant is &lt;span class=&quot;math-container&quot;&gt;$$H(T)=H(T_0)\exp\left[-\frac{\Delta K}{R}\left(T^{-1}-T_0^{-1}\right)\right]$$&lt;/span&gt; .&lt;span class=&quot;math-container&quot;&gt;$-\frac{\Delta K}{R}$&lt;/span&gt; is Wikipedia's version of &lt;span class=&quot;math-container&quot;&gt;$-\frac{\Delta_{sol} H}{R}$&lt;/span&gt;, but I used &lt;span class=&quot;math-container&quot;&gt;$K$&lt;/span&gt; to not cause confusion. For pure water, &lt;a href=&quot;https://www.engineeringtoolbox.com/gases-solubility-water-d_1148.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this link&lt;/a&gt; shows the solubility of different gases at different temperatures, but most relevant is the temperature at 0&lt;span class=&quot;math-container&quot;&gt;$^\circ$&lt;/span&gt;C (that is, it gives &lt;span class=&quot;math-container&quot;&gt;$H(T_0)$&lt;/span&gt;).&lt;/p&gt;&#xA;&lt;p&gt;But all of this doesn't answer the two questions that your question boils down to.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://courses.lumenlearning.com/cheminter/chapter/how-temperature-influences-solubility/#:%7E:text=As%20the%20kinetic%20energy%20of,decreases%20as%20the%20temperature%20increases.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Raising the temperature decreases the solubility of a gas.&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;If the pressure increases, then the amount of gas that can be dissolved increases per &lt;a href=&quot;https://en.wikipedia.org/wiki/Dalton%27s_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dalton's Law&lt;/a&gt;. If the system is not in equilibrium, then the amount of solute will increase in proportion to Henry's Law.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-04-17T21:51:57.613" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21131" PostTypeId="2" ParentId="21129" CreationDate="2021-04-18T04:14:02.913" Score="5" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;it was simply an older stone smoothed by water that had fallen into sediment.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is exactly what happened. There's a name for that: a &lt;a href=&quot;https://geology.com/rocks/conglomerate.shtml&quot; rel=&quot;noreferrer&quot;&gt;conglomerate&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-04-18T04:14:02.913" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21132" PostTypeId="1" CreationDate="2021-04-18T07:55:16.327" Score="2" ViewCount="92" Body="&lt;p&gt;A few years ago in Venezuela, parque nacional de Cainama, the tourist guide found and gave me this rocks, he told us that a geologist told him that those could be radioactive but no one believed him. Nowadays I'm very curious of what kind of rock it may be.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eu4gN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eu4gN.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22314" LastEditorUserId="22314" LastEditDate="2021-04-18T09:05:38.433" LastActivityDate="2021-04-18T09:05:38.433" Title="What kind of rock is this?" Tags="|geology|mineralogy|rocks|radioactivity|" AnswerCount="0" CommentCount="1" ClosedDate="2021-04-18T21:12:29.857" ContentLicense="CC BY-SA 4.0" />
  <row Id="21133" PostTypeId="1" CreationDate="2021-04-18T09:23:22.397" Score="4" ViewCount="193" Body="&lt;p&gt;In the region where I live, there is a trend that conservation organizations are advocating the conservation and re-valuation of wetlands.&lt;/p&gt;&#xA;&lt;p&gt;Aside from boosting biodiversity and providing other ecological services, the conservationists argue that wetlands capture a lot of carbon.&lt;/p&gt;&#xA;&lt;p&gt;I know however that wetlands are notorious for steady state methane emission [&lt;a href=&quot;https://ec.europa.eu/jrc/en/news/climate-change-projected-set-substantial-rise-methane-emissions-wetlands&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;][&lt;a href=&quot;https://en.wikipedia.org/wiki/Wetland_methane_emissions&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;], so it sounds dubious whether a single-time carbon-capture or carbon-release can compensate a significant steady-state emission of a potent greenhouse gas.&lt;/p&gt;&#xA;&lt;p&gt;Are there cost-benefit-analyses out there regarding the effect of wetlands on climate? What is your take?&lt;/p&gt;&#xA;" OwnerUserId="22315" LastActivityDate="2021-04-23T10:31:02.030" Title="Are wetlands effective against climate change?" Tags="|climate-change|co2|methane|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21134" PostTypeId="2" ParentId="21133" CreationDate="2021-04-18T10:43:24.110" Score="1" Body="&lt;p&gt;There's a misinterpretation in the &amp;quot;steady state&amp;quot; part, that's not what the linked paper says. It clearly states the figures are temperature dependent, and it says that in response to global warming wetlands are going to release more Methane and tries to quantify the amount. It &lt;a href=&quot;https://ec.europa.eu/jrc/en/publication/observation-constrained-assessment-climate-sensitivity-and-future-trajectories-wetland-methane&quot; rel=&quot;nofollow noreferrer&quot;&gt;concludes&lt;/a&gt; that&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This finding highlights the importance of limiting global warming below 2°C to avoid substantial climate feedbacks driven by methane emissions from natural wetlands.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;'&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017RG000559&quot; rel=&quot;nofollow noreferrer&quot;&gt;Feedback&lt;/a&gt;' is the keyword here. Such a feedback is an accelerated response of a system to global warming. Grossly simplifying, in case of small shallow wetlands CH&lt;sub&gt;4&lt;/sub&gt; release is connected to the level of oxic and anoxic conditions, the latter expanding not only in the table of a local 'puddle' but also geographically from lower to higher latitudes with temperature and so releasing more CH&lt;sub&gt;4&lt;/sub&gt; in a warmer climate, which warms the climate and so on. But the ability of these ecosystems to bind carbon from the atmosphere drops with rising temperature, and the amount of released carbon rises.&lt;/p&gt;&#xA;&lt;p&gt;That is by no means an argument against the conservationists who are advocating conservation and re-valuation to help &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0925857417303658&quot; rel=&quot;nofollow noreferrer&quot;&gt;sequester carbon&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This analysis can help inform practitioners and landscape managers [...] foster the worldwide implementation of wetland restoration, creation, and conservation projects for sustainable development and climate change mitigation and adaptation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So, yes, for now wetlands are effective against climate change as long as anthropogenic global warming is limited.&lt;/p&gt;&#xA;" OwnerDisplayName="user22279" LastEditorUserId="2470" LastEditDate="2021-04-23T10:21:57.237" LastActivityDate="2021-04-23T10:21:57.237" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="21135" PostTypeId="2" ParentId="21072" CreationDate="2021-04-18T20:53:05.970" Score="2" Body="&lt;p&gt;Strictly speaking, &lt;span class=&quot;math-container&quot;&gt;$\lim_{\Delta z \to 0} Ri=Ri_b$&lt;/span&gt;. This is because the &lt;a href=&quot;https://glossary.ametsoc.org/wiki/Gradient_richardson_number&quot; rel=&quot;nofollow noreferrer&quot;&gt;gradient Richardson number&lt;/a&gt;: &lt;span class=&quot;math-container&quot;&gt;$$Ri=\frac{\frac{g}{T_v}\frac{\partial \theta_v}{\partial z}}{\left(\frac{\partial U}{\partial z}\right)^2++\left(\frac{\partial V}{\partial z}\right)^2}$$&lt;/span&gt; can be approximated as &lt;span class=&quot;math-container&quot;&gt;$$Ri \approx\frac{\frac{g}{T_v}\frac{\Delta \theta_e}{\Delta z}}{\left(\frac{\Delta U}{\Delta z}\right)^2++\left(\frac{\Delta V}{\Delta z}\right)^2} \tag{1}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;which can be rewritten as the &lt;a href=&quot;https://glossary.ametsoc.org/wiki/Bulk_richardson_number&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bulk Richardson Number&lt;/a&gt;: &lt;span class=&quot;math-container&quot;&gt;$$Ri_b=\frac{\frac{g\Delta z \Delta \theta_v}{T_v}}{(\Delta U)^2+(\Delta V)^2} \tag{2}$$&lt;/span&gt;. The derivation of (2) from (1) is left as an exercise for the reader.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-04-18T20:53:05.970" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21136" PostTypeId="1" AcceptedAnswerId="21139" CreationDate="2021-04-19T00:03:23.687" Score="4" ViewCount="582" Body="&lt;p&gt;As a person living in Russia, I always had mixed feelings when hearing appeals to fight global warming. On the one hand, I completely understand that it is going to be a disaster for lots of people. On the other hand (a more egoistic one), it seems like it would be good for my country if the temperature would rise by a few degrees. The average temperature will become more comfortable for living in most Russian cities and Siberia may become more habitable. However, I might be overlooking some effects like coastal area flooding, damage to infrastructure or changes in flora or fauna.&lt;/p&gt;&#xA;&lt;p&gt;This makes me wonder, &lt;strong&gt;who might actually win from the global warming?&lt;/strong&gt; Is it just all cold countries (Russia, Canada, Scandinavian states, Iceland, etc.), or only part of them, or maybe everyone will lose?&lt;/p&gt;&#xA;" OwnerUserId="22316" LastActivityDate="2022-11-06T18:52:07.433" Title="Who are winners from the global warming? Are there any?" Tags="|climate-change|" AnswerCount="6" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="21137" PostTypeId="2" ParentId="21128" CreationDate="2021-04-19T01:11:27.010" Score="2" Body="&lt;p&gt;The workflow of fusing RGB true color image and panchromatic grayscale image can help understand this question. After converting RGB color space to the IHS space, the intensity component is replaced with the (high-resolutional) panchromatic image, and then the new intensity, hue, saturation combination as IHS are converted back to the original RGB space.&lt;/p&gt;&#xA;" OwnerUserId="11924" LastActivityDate="2021-04-19T01:11:27.010" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21138" PostTypeId="1" CreationDate="2021-04-19T07:55:12.100" Score="3" ViewCount="211" Body="&lt;p&gt;Given A is upper limit of sand stone, B is the lower limit of the planes that are equal in distance and dip. Dip angle is 29 degrees.&lt;/p&gt;&#xA;&lt;p&gt;Complete the outcrop of this map.&lt;/p&gt;&#xA;&lt;p&gt;—————————————————————————-&lt;/p&gt;&#xA;&lt;p&gt;Now I know that strike lines should go in height 400&lt;/p&gt;&#xA;&lt;p&gt;But there are 3 points so how could that even be possible.&lt;/p&gt;&#xA;&lt;p&gt;2 of these points are on strike line but what about the third?&lt;/p&gt;&#xA;&lt;p&gt;I really don’t know how to approach this question&lt;/p&gt;&#xA;&lt;p&gt;Also from dip angle I can easily find the distance from each strike line but that is for later&#xA;&lt;a href=&quot;https://i.stack.imgur.com/oEfTk.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oEfTk.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22318" LastEditorDisplayName="user20559" LastEditDate="2021-05-10T11:20:24.793" LastActivityDate="2021-05-10T11:20:24.793" Title="Complete missing outcrop problem" Tags="|geology|homework|mapping|topography|cartography|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21139" PostTypeId="2" ParentId="21136" CreationDate="2021-04-19T14:15:31.610" Score="10" Body="&lt;p&gt;Global economic costs of natural disasters:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In the period 1998-2017, disaster-hit countries reported direct&#xA;economic losses of 2,908 billion dolars of which climate-related disasters&#xA;accounted for 2,245 billion dolars or 77% of the total.&lt;/p&gt;&#xA;&lt;p&gt;This compares with total reported losses for the period 1978-1997 of 1,313 billion dolars of which climate-related disasters accounted for 895 billion dolars or 68%.&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.undrr.org/news/un-20-year-review-earthquakes-and-tsunamis-kill-more-people-while-climate-change-driving&quot; rel=&quot;noreferrer&quot;&gt;undrr.org&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The economic figures are frightening and climate change has been shown to increase these events all over the world. It is difficult to claim for specific countries winning anything at all with global warming after this introduction.&lt;/p&gt;&#xA;&lt;p&gt;Your assumption &amp;quot;...Siberia may become more habitable.&amp;quot; is proven false. Science find more extrem winters in East Asia and Europe after CC, even the average temperature raises and winters become shorter (emphasis mine):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Our simulations with the ECHAM5 general circulation model demonstrate that lower‐troposphere heating over the B‐K seas in the Eastern Arctic caused by the sea ice reduction may result in strong anticyclonic anomaly over the Polar Ocean and anomalous easterly advection over northern continents. This causes a continental‐scale winter cooling reaching −1.5°C, with more than 3 times increased probability of cold winter extremes over large areas including Europe. &lt;strong&gt;Our results imply that several recent severe winters do not conflict the global warming picture but rather supplement it&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Source&lt;/strong&gt;: &lt;a href=&quot;https://doi.org/10.1029/2009JD013568&quot; rel=&quot;noreferrer&quot;&gt;A link between reduced Barents‐Kara sea ice and cold winter extremes over northern continents&amp;quot;, &lt;em&gt;Climate and Dynamics&lt;/em&gt;&lt;/a&gt;, cited in &lt;a href=&quot;https://www.independent.co.uk/climate-change/news/expect-more-extreme-winters-thanks-to-global-warming-say-scientists-2168418.html&quot; rel=&quot;noreferrer&quot;&gt;Expect more extreme winters thanks to Global Warming, say scientists, Independent&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It could be debated the global beneficts of the opening of sea routes if the Arctic melts, but the costs all over the globe would exced the beneficts if we arrive to that scenario (economic looses due to floods in coastal cities among others).&lt;/p&gt;&#xA;&lt;p&gt;At a regional and local scale some industries may benefict from CC:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Places where summer heat atract new tourists.&lt;/li&gt;&#xA;&lt;li&gt;New agricultural products adapted to heat.&lt;/li&gt;&#xA;&lt;li&gt;....&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;But the costs for the region again far outweigh the benefits.&lt;/p&gt;&#xA;&lt;p&gt;In the first case the region will encounter problems as desertification, availability of water, biodiversity loss, ....&lt;/p&gt;&#xA;&lt;p&gt;The second case imply the ruling agriculturists loose their crops; as an example imagine what Bordeaux can win planting oranges instead of his known red wine despite some opportunistic individual may do fortune with it (...).&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-04-22T08:24:13.570" LastActivityDate="2021-04-22T08:24:13.570" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21142" PostTypeId="2" ParentId="21138" CreationDate="2021-04-19T23:49:41.723" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aJyy5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aJyy5.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;First step - draw a strike line where line A intersects the 400 m line.&lt;/p&gt;&#xA;&lt;p&gt;Second step - you know that the sandstone layer is of equal thickness and dip, so you can draw a parallel line at the place with line B intersects the 400 m line. This will give you the thickness, as expressed on a horizontal surface. You know what the dip angle is, so getting the real thickness is simple trigonometry.&lt;/p&gt;&#xA;&lt;p&gt;This should get you started.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-04-19T23:49:41.723" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="21144" PostTypeId="1" CreationDate="2021-04-20T17:38:43.867" Score="5" ViewCount="187" Body="&lt;p&gt;&lt;a href=&quot;https://www.usgs.gov/special-topic/water-science-school/science/raindrops-are-different-sizes?qt-science_center_objects=0#qt-science_center_objects&quot; rel=&quot;noreferrer&quot;&gt;This USGS article&lt;/a&gt;: &amp;quot;Raindrops are Different Sizes&amp;quot; assures:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;We can call the growing droplet a raindrop as soon as it reaches the size of 0.5mm in diameter or bigger. If it gets any larger than 4 millimeters, however, it will usually split into two separate drops.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;However, &lt;a href=&quot;https://elpais.com/ciencia/2021-04-20/las-gotas-de-lluvia-extraterrestre-son-como-las-de-la-tierra.html&quot; rel=&quot;noreferrer&quot;&gt;this article&lt;/a&gt; in the spanish newspaper El Pais: &amp;quot;Alien raindrops are like those on Earth&amp;quot; is contradictory:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The average diameter that a raindrop can have on Earth is 11.18 millimeters&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;A commenter on the news article says the article is wrong, but he says a raindrop can reach 6 milimeters and not 4.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The data for the average size of the raindrops on earth is wrong, since they rarely exceed 6 mm in diameter (equivalent). From this size, the drops become unstable and tend to divide into a pair of smaller drops.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;What is the maximum size that a drop of rainwater can reach before spliting into two separated drops?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-04-20T18:08:30.963" LastActivityDate="2021-04-20T18:08:30.963" Title="What is the maximum size that a drop of rainwater can reach?" Tags="|atmosphere|water|rain|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21147" PostTypeId="1" AcceptedAnswerId="21150" CreationDate="2021-04-21T14:06:43.143" Score="5" ViewCount="854" Body="&lt;p&gt;I have some data about PM10, PM2.5, i.e, how much is generated per day (in kilotonnes) by some sector, say from vehicular emissions. It can be converted to micrograms but I don't know how standard procedures/appliances calculate these values per cubic meter. Is it the mass divided by the volume of the region for which these components are to determined? If yes, then how is it possible in an open space? The area of a city makes sense, but volume doesn't.&lt;/p&gt;&#xA;" OwnerUserId="22335" LastEditorUserId="22335" LastEditDate="2021-05-03T17:58:45.340" LastActivityDate="2021-05-03T17:58:45.340" Title="How is the concentration of particulate matter calculated per cubic meter" Tags="|air-pollution|air-quality|particulates|pm2.5|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21148" PostTypeId="1" AcceptedAnswerId="21149" CreationDate="2021-04-21T18:26:52.883" Score="3" ViewCount="1297" Body="&lt;p&gt;As far as I know, the &lt;em&gt;EF-3&lt;/em&gt; El Reno tornado is by far the largest tornado since meteorologists have started observing them. Tornadoes also have eyes, like hurricanes, but are way too small compared to hurricanes. The El Reno tornado should make an exception, as it was 2.6 miles (4.2 kilometers) in diameter. But what about it’s eye? Can it be compared to a small hurricane, like Tropical Storm Marco? Even as the smallest hurricane, it’s still about 3.5 times the size of El Reno, so would their eyes have about the same ratio, or maybe a completely different ratio?&lt;/p&gt;&#xA;&lt;p&gt;P.S. A cyclone, a hurricane, and a typhoon are pretty much the same thing. I just use hurricane because I live in America.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;This is my fist question, so Im a little nervous :)&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="22338" LastEditorUserId="22338" LastEditDate="2021-04-21T19:22:59.693" LastActivityDate="2022-11-17T18:26:00.437" Title="How big was the eye of the El Reno tornado?" Tags="|meteorology|weather-forecasting|tornado|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21149" PostTypeId="2" ParentId="21148" CreationDate="2021-04-22T08:43:19.817" Score="2" Body="&lt;p&gt;There is no eye in the centre of a tornado's funnel, if we see the eye as a near circular cloudless area from bottom to tropopause, surrounded by a wall of towering clouds. Some interpretational leeway may lie in the &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2392/do-tornadoes-have-eyes&quot;&gt;low angular windspeed&lt;/a&gt; in the centre of the vortex, but that is not comparable to a &lt;a href=&quot;https://www.weather.gov/jetstream/tc_structure&quot; rel=&quot;nofollow noreferrer&quot;&gt;hurricane's eye&lt;/a&gt;. Force of the central updraft is still strong enough to keep debris in suspension.&lt;/p&gt;&#xA;&lt;p&gt;A vortex forms from updraft, warm air including 'macroscopic particles' is sucked into the cloud, while a hurricane's eye forms because of sinking air in the centre of a much larger and longer lasting storm system. There may, though, be water spouts under the individual thunderstorms of a hurricane's eyewall. Cause for rotation of a hurricane is coriolis force, while the vortex rotation is thought to be caused by vertical windsheer in the horizontal inflow. Hurricanes gain their energy from warm sea water, while thunderstorms are caused by vertical labilization of the atmosphere along a frontal line.&lt;/p&gt;&#xA;&lt;p&gt;Here's a &lt;a href=&quot;https://journals.ametsoc.org/view/journals/mwre/143/7/mwr-d-15-0034.1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;publication&lt;/a&gt; about the El Reno tornado. No structure that could be interpreted as an eye can be found in the interpretation of the radar data (Figure 15), and there's still a huge black thundercloud right above it.&lt;/p&gt;&#xA;&lt;p&gt;Thunderstorms with tornados and tropical storms like hurricanes and typhoons are fundamentally different in how they form and evolve, their size and structure, much information on both phenomena can be found on the internet.&lt;/p&gt;&#xA;&lt;p&gt;And, btw., TS Marco 2008 didn't have an eye either, I believe.&lt;/p&gt;&#xA;" OwnerDisplayName="user22279" LastEditorDisplayName="user22279" LastEditDate="2021-04-22T11:13:53.520" LastActivityDate="2021-04-22T11:13:53.520" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21150" PostTypeId="2" ParentId="21147" CreationDate="2021-04-22T09:45:45.887" Score="8" Body="&lt;p&gt;The data that you are having are called emission fluxes. If these data are available as global averages then one can calculate global mean concentration by multiplying the residence time of the species with emission flux.&lt;/p&gt;&#xA;&lt;p&gt;However, at the city or grid level, it is not straightforward to calculate concentration from emission fluxes. In order to calculate, concentration, one requires information of rate of dispersion in three dimensions as well as species amount brought-in by the wind. The dispersion is generally estimated using atmospheric transport models. See for example Gadhavi et al. (2015) have estimated concentration from emission fluxes for black carbon particles.&lt;/p&gt;&#xA;&lt;p&gt;Technically speaking, one can calculate concentration by first dividing the region where the concentration is needed in three dimensional grid-boxes and by calculating mass fluxes at each interface of the grid-boxes as well as chemical transformation within box. The chemical transformation for species like PM10 or PM2.5 may not be significant but it can be significant for species like SO2. The mass flux calculations will require knowledge on wind velocities across interfaces, diffusion mixing and turbulent mixing within the box as well as removal processes such as dry deposition and wet deposition.&lt;/p&gt;&#xA;&lt;p&gt;Here, a confusing issue is the size of grid-boxes. A different size may lead to a different concentration number. Though, there is no hard and fast rule about size of grid-boxes, the decision often depends on resolution of available flux and meteorological data as well as end purpose. Suppose, one is looking for comparing satellite based columnar concentration, he/she may take grid-box height that covers entire atmosphere but if one is planning to compare a surface mass concentration measurement typically obtained by air pollution monitoring stations, vertical height of grid-box should be as small as possible preferably less than boundary layer height.&lt;/p&gt;&#xA;&lt;p&gt;Most emission flux data or emission inventories are available for the emission near Earth's surface. They should be considered as emission flux across the bottom face of the lowest grid-box. The grid box that one but the lowest grid-box will have emission fluxes from top of the lowest grid-box dictated by meteorology and dispersion physics. And the gain of this grid-box will be losses (or negative flux) of the lowest grid box. Besides, losing mass to above, the lowest grid-boxes will also loose mass through process called dry deposition. If the grid-boxes covers the region with rain, then all the grid-boxes from cloud level to surface will also have wet deposition or wet removal. Same applies to mass fluxes in horizontal direction. The lowest grid-box gains mass from bottom face because of emissions but looses to neighboring boxes by horizontal wind. A balance between mass fluxes across all the faces will be concentration of given grid-box.&lt;/p&gt;&#xA;&lt;p&gt;A crude estimation of surface concentration can be obtained by making a certain assumptions, like by taking grid-box height equal to mixing layer height and assuming horizontally uniform emission fluxes across large region. Under this assumptions one can calculate concentration by multiplying emission fluxes with characteristic time period say 24 hour and dividing it by volume of grid-box. The scientific rational behind this assumption is that mixing height is the height of the atmosphere were turbulence is very high and the loss process becomes dominant only after this volume is filled. Also, when the emission region is sufficiently large, horizontal movement of mass will cancel out across opposing face of the grid-box.&lt;/p&gt;&#xA;&lt;h2&gt;Reference&lt;/h2&gt;&#xA;&lt;p&gt;Gadhavi, H. S., Renuka, K., Ravi Kiran, V., Jayaraman, A., Stohl, A., Klimont, Z., and Beig, G.: Evaluation of black carbon emission inventories using a Lagrangian dispersion model – a case study over southern India, Atmos. Chem. Phys., 15, 1447–1461, &lt;a href=&quot;https://doi.org/10.5194/acp-15-1447-2015&quot; rel=&quot;noreferrer&quot;&gt;https://doi.org/10.5194/acp-15-1447-2015&lt;/a&gt;, 2015.&lt;/p&gt;&#xA;&lt;p&gt;Chapter 2 Atmospheric Trace Constituents in Atmospheric Chemistry and Physics by Seinfeld and Pandis, 2006.&lt;/p&gt;&#xA;" OwnerUserId="10780" LastEditorUserId="10780" LastEditDate="2021-04-23T13:45:37.120" LastActivityDate="2021-04-23T13:45:37.120" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21151" PostTypeId="5" CreationDate="2021-04-22T10:35:20.087" Score="0" Body="&lt;p&gt;VEIN is an R package that currently has more than 17K downloads in the version 0.9.0.1on CRAN &lt;a href=&quot;https://cran.r-project.org/package=vein&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://cran.r-project.org/package=vein&lt;/a&gt;. VEIN includes emission factors for China, Europe, and Latin America, and soon the USA.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-04-22T10:35:20.087" LastActivityDate="2021-04-22T10:35:20.087" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21152" PostTypeId="4" CreationDate="2021-04-22T10:35:20.087" Score="0" Body="To be used for questions asking about vehicle emissions ( from internal combustion engines) when data is being analyzed by the VEIN R package." OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-04-22T10:35:20.087" LastActivityDate="2021-04-22T10:35:20.087" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21153" PostTypeId="5" CreationDate="2021-04-22T10:42:04.497" Score="0" Body="&lt;p&gt;A geological vein is a tabular or sheet-like body of minerals which has been intruded into a joint, fissure or system of joints and fissures in rocks. &lt;em&gt;Penguin Dictionary of Geology&lt;/em&gt;, 1979.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-04-22T10:42:04.497" LastActivityDate="2021-04-22T10:42:04.497" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21154" PostTypeId="4" CreationDate="2021-04-22T10:42:04.497" Score="0" Body="For questions about geological veins.&#xD;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-04-22T10:42:04.497" LastActivityDate="2021-04-22T10:42:04.497" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21156" PostTypeId="1" AcceptedAnswerId="21157" CreationDate="2021-04-22T16:52:08.210" Score="8" ViewCount="301" Body="&lt;p&gt;Taking a look at Google Earth the straits between the Caribbean Sea and the Atlantic Ocean are not very deep.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iSe1q.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iSe1q.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The sealevel during the last glaciation was 120 meters lower than the present level.&lt;/p&gt;&#xA;&lt;p&gt;Was the Caribbean Sea a closed or semi-closed sea during the last glaciation or the straits were deep enough to make it a connected sea?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-09-22T13:02:56.213" LastActivityDate="2021-09-22T16:40:58.697" Title="Was the Caribbean Sea a closed sea during the last glaciation?" Tags="|oceanography|stratigraphy|paleogeography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21157" PostTypeId="2" ParentId="21156" CreationDate="2021-04-22T17:53:44.930" Score="5" Body="&lt;p&gt;Thanks to @Eartworm I learned today I was totally incorrect: the straits are more than 2000 meters deep.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nmrih.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nmrih.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://webapp.navionics.com/?lang=en#boating@3&amp;amp;key=o%7BkwA%7CukyM&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tool to see bathymetry, navionics.com&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorUserId="2470" LastEditDate="2021-09-22T16:40:58.697" LastActivityDate="2021-09-22T16:40:58.697" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21158" PostTypeId="1" AcceptedAnswerId="21248" CreationDate="2021-04-22T18:24:39.530" Score="4" ViewCount="3482" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;The Gulf Stream is the fastest ocean current in the world with peak&#xA;velocities near 2m/s.&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://marine.coastal.edu/gulfstream/p2a.htm#:%7E:text=Gulf%20Stream%20Velocity,peak%20velocities%20near%202m%2Fs.&quot; rel=&quot;nofollow noreferrer&quot;&gt;marine.coastal.edu&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;What about deep currents, &lt;a href=&quot;https://en.wikipedia.org/wiki/North_Atlantic_Deep_Water&quot; rel=&quot;nofollow noreferrer&quot;&gt;North Atlantic Deep Water&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Antarctic_bottom_water&quot; rel=&quot;nofollow noreferrer&quot;&gt;Antarctic Bottom Water&lt;/a&gt;, etc?&lt;/p&gt;&#xA;&lt;p&gt;What is the fastest ocean deep current?&lt;/p&gt;&#xA;&lt;p&gt;My guess is Antarctic Bottom Water must be the fastest because Antarctic Circumpolar Current receives not salty water from ice melt, and salinity gradient moves deep currents.&lt;/p&gt;&#xA;&lt;p&gt;Is Antarctica Bottom Water the fastest?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-05-10T13:08:45.983" LastActivityDate="2021-05-10T13:39:48.933" Title="What is the fastest ocean deep current?" Tags="|oceanography|ocean-currents|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21160" PostTypeId="1" CreationDate="2021-04-22T19:04:11.793" Score="1" ViewCount="87" Body="&lt;p&gt;I want to make an app for smartphones that lists the mountain chains of the world.&lt;/p&gt;&#xA;&lt;p&gt;Where can I find a list of all mountain chains that are presently outspread on the Earth?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorUserId="2470" LastEditDate="2021-04-23T05:38:14.060" LastActivityDate="2021-04-23T05:38:14.060" Title="Where can I find a list of mountain chains on the Earth?" Tags="|geography|mountains|topography|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="21161" PostTypeId="1" AcceptedAnswerId="21164" CreationDate="2021-04-22T19:49:47.863" Score="15" ViewCount="3841" Body="&lt;p&gt;The Puget Sound region is wedged between the Pacific and the Cascades...you'd think with all that rain (and snowmelt in the warmer months), there would be catastrophic flash flooding in lowland areas, of the magnitude seen in Oklahoma (&lt;a href=&quot;https://www.weather.gov/oun/events-20130531-flooding&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;https://www.weather.gov/oun/events-20100614&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;, &lt;a href=&quot;https://www.weather.gov/tsa/1984may26_tulsamemorialdayflood&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;), Texas (&lt;a href=&quot;https://www.weather.gov/hgx/hurricaneharvey&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;https://www.hcfcd.org/Portals/62/Downloads/TS%20Imelda%20Flood%20Report/TS%20Imelda%20Flood%20Report-Final.pdf?ver=4JBzaMh-DydlHHx9_mlZgg%3D%3D&amp;amp;timestamp=1619119442827&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;, &lt;a href=&quot;http://aipg-tx.org/_docs/TaxDayFlood_HGS.pdf&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;, &lt;a href=&quot;http://hurricane.egr.uh.edu/sites/hurricane.egr.uh.edu/files/files/2015/1-2015-MEMORIAL-DAY-FLOOD-8-4-2015.pdf&quot; rel=&quot;noreferrer&quot;&gt;4&lt;/a&gt;) or Tennessee (&lt;a href=&quot;https://www.weather.gov/ohx/20210327&quot; rel=&quot;noreferrer&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;https://www.weather.gov/ohx/lateFebruary2019flooding&quot; rel=&quot;noreferrer&quot;&gt;2&lt;/a&gt;, &lt;a href=&quot;https://www.weather.gov/ohx/may2010flood&quot; rel=&quot;noreferrer&quot;&gt;3&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;On the contrary, western WA is actually subject to &lt;a href=&quot;https://1.bp.blogspot.com/-dtVzVuG-95Y/XV6PnEkANaI/AAAAAAAA3Vc/kAPFcCvfR3Q23SUyHUEIcL1h4CZysYNTgCEwYBhgL/s1600/20190820_WA_trd.png&quot; rel=&quot;noreferrer&quot;&gt;droughts&lt;/a&gt; and &lt;a href=&quot;https://static.seattletimes.com/wp-content/uploads/2017/08/08042017_moreseattlehaze_0645152-780x1170.jpg&quot; rel=&quot;noreferrer&quot;&gt;wildfires&lt;/a&gt;, not something you'd expect from such a wet region with rainforests.&lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2022-02-05T07:55:22.573" Title="With all the rain Seattle gets, why is widespread flooding relatively rare?" Tags="|meteorology|severe-weather|flooding|" AnswerCount="6" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21162" PostTypeId="2" ParentId="21161" CreationDate="2021-04-22T21:48:15.690" Score="4" Body="&lt;p&gt;&lt;strong&gt;Because soil drainage would be higher and the ground would take long to saturate&lt;/strong&gt; Floods don't always happen in Rainy weather all the time because first the soil needs to be saturated (the point where it filled up with water) then the rain needs to continue, Flash floods are mostly produced this way.&lt;/p&gt;&#xA;&lt;p&gt;So you would need lots of rain for a flood to occur in WA, I mean lots.&lt;/p&gt;&#xA;" OwnerUserId="21926" LastActivityDate="2021-04-22T21:48:15.690" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21163" PostTypeId="2" ParentId="21161" CreationDate="2021-04-22T22:19:12.233" Score="19" Body="&lt;p&gt;Catastrophic flash flooding is usually a sign of poor city/road planning in flat areas or due to torrential downfall of rain.   The reality is that all the terrain in Washington allows water to drain, rather than be left standing (which causes flash flooding).  And let's be clear, it doesn't rain hard in WA very often, it's usually not torrential downpour, but rather a slow methodical drizzle that can easily drain away down rivers and streams.  A lot of development in the mid-west ignores known flood plains.&lt;/p&gt;&#xA;&lt;p&gt;As for your comment about wildfires, WA gets its rain in the cold seasons.  So there is usually very dry weather in the summer when wildfires occur.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="7314" LastEditDate="2022-01-30T16:51:55.450" LastActivityDate="2022-01-30T16:51:55.450" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21164" PostTypeId="2" ParentId="21161" CreationDate="2021-04-22T22:27:00.290" Score="26" Body="&lt;p&gt;Regarding climate, it does not rain in Seattle as much as people think; Seattle is in the snow shadow of the Olympic Mountains. It doesn't rain much in summer at all. Seattle gets rather dry in July and August.&lt;/p&gt;&#xA;&lt;p&gt;Regarding flooding, the Skagit and Snohomish rivers north of Seattle flood regularly experience flooding. Some of the land in the flood plain is used for farming, and there are scattered households in the 100 year flood plain.&lt;/p&gt;&#xA;&lt;p&gt;Regarding drought, drought severity is relative to the amount of precipitation and soil moisture levels typical for a specific locale. This means that even a rainforest can suffer drought. Because it's a relative concept, the rainfall during a drought in a rainforest would be a rainfall bonanza in arid climates.&lt;/p&gt;&#xA;&lt;p&gt;Regarding forest fires, the Seattle area occasionally undergoes offshore flow. This occurs when the air pressure is lower in the Seattle area than it is east of the Cascades. This makes winds blow from the east, and if there's a forest fire east of the Cascades (which has a rather dry climate), that smoke can be carried westward toward the Seattle area by the offshore flow. That said, wildfires have occurred on the western slopes of the Cascades, and sometimes even in the temperate rainforest to the west of the Seattle area.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2021-04-23T20:35:57.957" LastActivityDate="2021-04-23T20:35:57.957" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="21165" PostTypeId="2" ParentId="21133" CreationDate="2021-04-23T01:09:41.953" Score="0" Body="&lt;p&gt;It seems that there is indeed a strong &amp;quot;climate-case&amp;quot; in favour of wetlands: Below follows a bullet-list of several facts and arguments, which among other things undermine the premises of my question (to a certain degree):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Currently, 3% of the land surface is covered by peat lands. But it is estimated that up to 1/3 of all terrestrial carbon is stored in those peat lands, giving a big edge in carbon sequestration/m&lt;sup&gt;2&lt;/sup&gt; over any other type of vegetation. Although these peat lands convert some of their intake of CO&lt;sub&gt;2&lt;/sub&gt; in the more potent greenhouse gas CH&lt;sub&gt;4&lt;/sub&gt;, it is clear that the remedy is certainly not to 'drain the swamp' in a short time-window in a way where all the carbon is injected in the atmosphere. Since the latter is exactly the threat posed to many wetlands nowadays, there is clear and in some cases perhaps decisive motivation and urgency for the conservation and protection of existing wetlands.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Organic methanogenesis appears strongly temperature-dependent: &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0034425718300178&quot; rel=&quot;nofollow noreferrer&quot;&gt;satellite data&lt;/a&gt; show the tropical regions as the main global sources. &lt;a href=&quot;https://academic.oup.com/femsec/article/22/3/207/559904&quot; rel=&quot;nofollow noreferrer&quot;&gt;Laboratory experiments roughly confirm that picture&lt;/a&gt;, although many questions remain unanswered and methanogenesis seems to depend on a wide range of variables. In any case, in temperate and boreal regions the wetland-contribution in CH&lt;sub&gt;4&lt;/sub&gt;-emission often pales in comparison to agricultural and industrial sources (in Flanders, agriculture contributes 20-fold the CH&lt;sub&gt;4&lt;/sub&gt; contribution from rivers and wetlands). Hence, in densely-populated temperate and boreal regions, the CH&lt;sub&gt;4&lt;/sub&gt;-emission-argument may be moot since there are more opportune alternative options for climate-change mitigation, with less collateral consequences (wetlands provide biodiversity, hydrological stability etc).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The argument that wetlands saturate and stop net intake of carbon may be partly false and largely irrelevant: A mature peatland may reach a depth varying from 2 to 20 meters, while &lt;a href=&quot;https://en.wikipedia.org/wiki/Peat&quot; rel=&quot;nofollow noreferrer&quot;&gt;a peatland's annual growth is typically of order 1 mm/ year&lt;/a&gt;. With some audacity, I propose to infer that a peatland then needs a time of order 10m/(10&lt;sup&gt;-3&lt;/sup&gt; m/year)= 10000 years to grow to maturity. During that time, it did absorb carbon to grow. Since 10000 years dwarfs the time-scale in which humanity is to overcome and adapt to climate change, the saturation-argument against reinstating or re-valuation of peatlands is irrelevant. The saturation-argument might be weakened even more if one includes in the calculation the depth of the &lt;a href=&quot;https://www.nationalgeographic.org/encyclopedia/coal/#:%7E:text=Under%20the%20right%20conditions%2C%20peat,(1%20foot)%20of%20coal!&quot; rel=&quot;nofollow noreferrer&quot;&gt;coal-seam which is often found below a mature peatland&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="22315" LastEditorUserId="2470" LastEditDate="2021-04-23T10:31:02.030" LastActivityDate="2021-04-23T10:31:02.030" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21166" PostTypeId="1" CreationDate="2021-04-23T03:31:34.197" Score="3" ViewCount="3450" Body="&lt;p&gt;Is it possible to reduce the level of carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;) in the atmosphere by converting it into a solid, thus reducing the level of greenhouse gases?&lt;/p&gt;&#xA;" OwnerUserId="22350" LastEditorUserId="6129" LastEditDate="2021-04-23T22:14:02.083" LastActivityDate="2021-04-23T22:14:02.083" Title="Is it possible to convert carbon dioxide into a solid at low cost?" Tags="|carbon-cycle|carbon|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21167" PostTypeId="2" ParentId="21166" CreationDate="2021-04-23T07:10:47.043" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://www.rmit.edu.au/news/all-news/2019/feb/carbon-dioxide-coal#:%7E:text=The%20CO%202%20slowly%20converts%20into%20solid%20flakes,produced%20could%20also%20be%20used%20as%20an%20electrode.&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; in the press cites CO&lt;sub&gt;2&lt;/sub&gt; has been converted  into Carbon at relative low temperature.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The research team led by RMIT University in Melbourne, Australia, have developed a new technique that can efficiently convert CO2 from a gas into solid particles of carbon.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;To date, CO2 has only been converted into a solid at extremely high temperatures, making it industrially unviable.&lt;/p&gt;&#xA;&lt;p&gt;By using liquid metals as a catalyst, we’ve shown it’s possible to turn the gas back into carbon at room temperature, in a process that’s efficient and scalable.&lt;/p&gt;&#xA;&lt;p&gt;While more research needs to be done, it’s a crucial first step to delivering solid storage of carbon.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The study &lt;a href=&quot;https://www.nature.com/articles/s41467-019-08824-8#&quot; rel=&quot;nofollow noreferrer&quot;&gt;is published in Nature Communications&lt;/a&gt;. They used cerium oxyde as catalyst to reduce the temperature of the reaction.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;... which facilitates the electrochemical reduction of CO2 to layered&#xA;solid carbonaceous species, at a low onset potential of −310 mV vs&#xA;CO2/C&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;All these CO&lt;sub&gt;2&lt;/sub&gt; sequestration issues are under investigation and will be implemented in the coming years by energy companies.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;Esrafilzadeh, D., Zavabeti, A., Jalili, R. et al. (2019)&lt;/strong&gt;: &amp;quot;Room temperature CO2 reduction to solid carbon species on liquid metals featuring atomically thin ceria interfaces.&amp;quot; &lt;em&gt;Nat Commun&lt;/em&gt; 10, 865. &lt;a href=&quot;https://doi.org/10.1038/s41467-019-08824-8&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1038/s41467-019-08824-8&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-04-23T07:35:49.500" LastActivityDate="2021-04-23T07:35:49.500" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21168" PostTypeId="1" AcceptedAnswerId="21267" CreationDate="2021-04-23T08:52:03.480" Score="4" ViewCount="437" Body="&lt;p&gt;I guess the Pacific Ocean evaporates the most water because of its size.&lt;/p&gt;&#xA;&lt;p&gt;But which of the major oceans evaporates the most water per square meter?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorUserId="2470" LastEditDate="2021-04-23T10:18:14.893" LastActivityDate="2021-05-16T21:37:15.637" Title="Which ocean evaporates the most water per surface area?" Tags="|atmosphere|oceanography|evaporation|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21169" PostTypeId="1" CreationDate="2021-04-23T10:09:31.180" Score="1" ViewCount="59" Body="&lt;p&gt;The article &lt;a href=&quot;https://pledgetimes.com/did-the-earths-magnetic-field-affect-our-evolution/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Did the Earth’s magnetic field affect our evolution?&lt;/a&gt; on Pledge Times cite &lt;a href=&quot;https://science.sciencemag.org/content/371/6531/811.abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;this Science paper&lt;/a&gt; to assert:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;These authors speculate that, in the Pleistocene, large mammals could have reached a natural limit of body size until the arrival of Laschamps, when the probability of cell mutation would increase at times of high ultraviolet ray flux. It would not be a catastrophic, instantaneous extinction, but rather an accumulation of mutations produced by radiation over multiple generations, over several thousand years, which is the duration of the minimum intensity of the geomagnetic field during geomagnetic inversions.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;My question is: Is there any study correlating other geomagnetic inversions with extinctions in fauna?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;Alan Cooper et al(2021)&lt;/strong&gt;: &amp;quot;A global environmental crisis 42,000 years ago.&amp;quot; &lt;em&gt;Science&lt;/em&gt;  19 Feb 2021. Vol. 371, Issue 6531, pp. 811-818&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastActivityDate="2021-04-23T10:09:31.180" Title="Extinctions and geomagnetic inversions" Tags="|geology|paleontology|geomagnetism|" AnswerCount="0" CommentCount="5" ClosedDate="2021-05-09T10:31:34.340" ContentLicense="CC BY-SA 4.0" />
  <row Id="21170" PostTypeId="1" AcceptedAnswerId="21172" CreationDate="2021-04-23T10:20:45.860" Score="3" ViewCount="107" Body="&lt;p&gt;Can someone help me identify &lt;a href=&quot;https://www.google.es/maps/@69.2125436,154.2942761,53057m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;this peculiar geographical feature I've noticed in satellite imagery&lt;/a&gt;?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QC1Cq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QC1Cq.png&quot; alt=&quot;Satellite image of northern Russia&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This particular screenshot is from satellite imagery of northern Russia, however this kind of geography appears extremely common in the northernmost latitudes of both Russia, Canada, and the United States.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.es/maps/@70.4076467,-153.5539541,50130m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;The below image is from Alaska&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/I8Mk1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/I8Mk1.png&quot; alt=&quot;Satellite image of northern Alaska&quot; /&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I've always wondered how this landscape would be described. Is this marshland, or swamps, or something else in particular?&#xA;Thank you!&lt;/p&gt;&#xA;" OwnerUserId="22352" LastEditorDisplayName="user20559" LastEditDate="2021-04-23T11:29:25.837" LastActivityDate="2021-04-23T13:41:03.393" Title="What is this geographical feature? (as seen in maps)" Tags="|groundwater|land-surface|landscape|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21171" PostTypeId="1" CreationDate="2021-04-23T13:06:48.463" Score="6" ViewCount="253" Body="&lt;p&gt;I have a question about planetology. I'm not sure if it belongs here, but the astronomy stack exchange seemed a bit odd, too.&lt;/p&gt;&#xA;&lt;p&gt;I would like to enhance my understanding of Love numbers. Love numbers quantify the deviation from equilibrium tides on a planet. For a homogeneous body, you can write, for example&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ k_2 = \frac{3}{2}\Big(1 + \frac{19}{2}\frac{\mu}{\rho gR}\Big)^{-1}$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$\mu$&lt;/span&gt; is the rigidity, &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; is the density, &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; is the radius of the planet and &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; is the gravity constant. I have been taught that for non-homogeneous bodies, e.g. planets with a core etc, there is no simple analytical expression and you need numerical techniques. I have been reading a &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2018JE005569&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt; about exactly that, but I don't see what equations are used to obtain &lt;span class=&quot;math-container&quot;&gt;$k_2$&lt;/span&gt;. In this article, the interior of the planet is described by Maxwell models and a pseudo-period Andrade model. These rheological models are used in conjunction with so called structural models for the interior. It's not clear to me what these are, either. I think they are equations for pressure and temperature. The article then says: &lt;em&gt;&amp;quot;Based on these, the tidal Love number &lt;span class=&quot;math-container&quot;&gt;$k_2$&lt;/span&gt; is calculated and compared against measurement.&amp;quot;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Does anyone know what equation needs to be solved to obtain the &lt;span class=&quot;math-container&quot;&gt;$k_2$&lt;/span&gt; Love number? Or what steps need to be taken to do such a calculation? Or if you know a relevant reference, anything is greatly appreciated, because I don't know where to start.&lt;/p&gt;&#xA;&lt;p&gt;EDIT: I found a calculation for planets in hydrostatic equilibrium (see my own answer below). If someone knows the equations for a terrestrial planet with viscoelastic behaviour, I would still be interested in that.&lt;/p&gt;&#xA;" OwnerUserId="22353" LastEditorUserId="22353" LastEditDate="2021-04-29T13:56:47.080" LastActivityDate="2021-04-29T13:56:47.080" Title="Calculating Love numbers (tidal deformation) for non-homogeneous planets" Tags="|planetary-science|numerical-modelling|tides|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21172" PostTypeId="2" ParentId="21170" CreationDate="2021-04-23T13:29:43.377" Score="3" Body="&lt;p&gt;The dark color of the water masses make me think they are &lt;a href=&quot;https://en.wikipedia.org/wiki/Mire&quot; rel=&quot;nofollow noreferrer&quot;&gt;peatlands&lt;/a&gt; in &lt;a href=&quot;https://en.wikipedia.org/wiki/Tundra&quot; rel=&quot;nofollow noreferrer&quot;&gt;tundra&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Peatland is a terrestrial wetland ecosystem in which the production of&#xA;organic matter exceeds its decomposition and a net accumulation of&#xA;peat results.&lt;/p&gt;&#xA;&lt;p&gt;The largest known concentrations of peatland are &lt;strong&gt;found in Canada and&#xA;Alaska, Northern Europe and Western Siberia&lt;/strong&gt;, Southeast Asia, and parts&#xA;of the Amazon basin, where more than 10% of the land area is covered&#xA;with peatlands.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://peatlands.org/peatlands/&quot; rel=&quot;nofollow noreferrer&quot;&gt;peatlands.org&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-04-23T13:41:03.393" LastActivityDate="2021-04-23T13:41:03.393" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21173" PostTypeId="2" ParentId="21161" CreationDate="2021-04-23T22:27:55.000" Score="7" Body="&lt;p&gt;We do get flooding in the Puget Sound lowlands, but it actually happens most often when a mid-winter warm front brings a moderate amount of rain to higher elevations, causing sudden, extensive snowmelt.&lt;/p&gt;&#xA;&lt;p&gt;Those weather systems, like one in February 2020 that caused quite a bit of flooding, suddenly raise temps by 15-20 degrees C (20-30 °F), and raise the snow/rain threshold up by 1000 meters (a few thousand feet) or more overnight.  Even though the rainfall totals in those storms are usually not that great by comparison with the major storms in the South or the Plains, 5 cm/day (1-2 inches per day), the net effect is that a huge amount of water enters waterways all at once.&lt;/p&gt;&#xA;&lt;p&gt;Even so, the steep slopes in the area generally mean that flooding is limited to a few river valleys.  Our elevation profile goes from 3000 meters (8000 feet) to sea level in about 50 km (30 miles), so that water heads downhill FAST.&lt;/p&gt;&#xA;" OwnerUserId="22359" LastEditorUserId="2470" LastEditDate="2021-04-25T04:48:52.233" LastActivityDate="2021-04-25T04:48:52.233" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21174" PostTypeId="1" CreationDate="2021-04-24T06:21:09.487" Score="3" ViewCount="56" Body="&lt;p&gt;Consider this : &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth_mass#Variation&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Earth_mass#Variation&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;To quote:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The main factor in mass gain is in-falling material, cosmic dust, meteors, etc. are the most significant contributors to Earth's increase in mass. The sum of material is estimated to be 37000 to 78000 tons annually&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I would like to know, if there is an estimate of chemical composition of mass. That is , I am looking for a categorization of this mass in x% Carbon, y% Silicon, etc.&lt;/p&gt;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="313" LastActivityDate="2021-04-24T06:21:09.487" Title="What is the typical chemical composition of Earth's mass gain" Tags="|meteorite|earth-system|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21175" PostTypeId="1" CreationDate="2021-04-24T08:45:47.977" Score="1" ViewCount="22" Body="&lt;p&gt;I am working on the conversion of CSF file from SonarWiz  into SEG-Y data. However, it comes back always related to the Sensor depth/altitude and never to the MSL.&#xA;I have tried changing the bytes from 61 to 69 to water depth info, I have tried editing the trace header and the EBCDIC Header.&#xA;But until now, I haven't managed to make it work.&lt;/p&gt;&#xA;&lt;p&gt;Does anyone know how I fix this on the data?&#xA;I tried reading the SEG-Y definition document and there was something about location data stanza, but is this the only way ? And if it is, how do I create this?&lt;/p&gt;&#xA;&lt;p&gt;PS: The data opens related to MSL in some softwares, but not in Seisee, which is where the client checks the data. Is there an explanation for this?&lt;/p&gt;&#xA;&lt;p&gt;Thank you for any help!!&lt;/p&gt;&#xA;" OwnerUserId="22362" LastActivityDate="2021-04-24T08:45:47.977" Title="Conversion of SEG-Y relative to MSL" Tags="|geophysics|seismic|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21176" PostTypeId="1" AcceptedAnswerId="21181" CreationDate="2021-04-24T12:15:16.907" Score="1" ViewCount="124" Body="&lt;p&gt;The Carboniferous was a period where CO&lt;sub&gt;2&lt;/sub&gt; levels fell drastically.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Vsouw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Vsouw.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0009254113004488?via%3Dihub&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geologic history of seawater: A MAGic approach to carbon chemistry and ocean ventilation&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I think the main reasons are tectonic settings and the formation of coal deposits with the arrival of lignite-rich plants that bacteria didn't know yet how to decompose.&lt;/p&gt;&#xA;&lt;p&gt;My question here is:&lt;/p&gt;&#xA;&lt;p&gt;Forgetting Carboniferous plants were efficient sequestrating CO&lt;sub&gt;2&lt;/sub&gt; forming coal deposits after dying, were &lt;strong&gt;living&lt;/strong&gt; Carboniferous plants more efficient sequestering CO&lt;sub&gt;2&lt;/sub&gt; than present plants?&lt;/p&gt;&#xA;&lt;p&gt;Meaning, would a Carboniferous forest be more efficient than present forests to sequestrate CO&lt;sub&gt;2&lt;/sub&gt; nowadays?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorUserId="2470" LastEditDate="2021-04-24T15:23:18.757" LastActivityDate="2021-04-24T18:23:09.093" Title="Were Carboniferous plants more efficient sequestering $\ce{CO2}$ than present plants?" Tags="|climate|paleoclimatology|plant|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="21177" PostTypeId="2" ParentId="21171" CreationDate="2021-04-24T14:42:50.650" Score="2" Body="&lt;p&gt;I actually just found an article that explains such a calculation in detail, using a matrix propagator method: &lt;a href=&quot;https://www.aanda.org/articles/aa/pdf/2018/12/aa34181-18.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Padovan et al. 2018&lt;/a&gt;&#xA;This is a calculation for gas giants or bodies in hydrostatic equilibrium. The calculation of the Love numbers for terrestrial planets that have viscoelastic behaviour requires the rheology (which includes models for the rigidity). I did not find the equations that need to be solved in that case, but a similar matrix propagator method can be used apparently.&lt;/p&gt;&#xA;&lt;p&gt;I will not repeat the matrix propagation method here, as it is quite well elaborated in the paper I just mentioned, except for the equation you have to start from, which is explained in another article, but looks a bit too complicated for me at this point.&lt;/p&gt;&#xA;" OwnerUserId="22353" LastEditorUserId="22353" LastEditDate="2021-04-29T13:54:12.497" LastActivityDate="2021-04-29T13:54:12.497" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21178" PostTypeId="1" CreationDate="2021-04-24T16:45:44.013" Score="1" ViewCount="926" Body="&lt;p&gt;The model I use needs the data of Air humidity and unit is 'mb' (there is no other explanations about this variable), but now I only have two datasets and there are Relative humidity (%) or Specific humidity (kg/kg).&#xA;(Specific humidity: This parameter is the mass of water vapour per kilogram of moist air. The total mass of moist air is the sum of the dry air, water vapour, cloud liquid, cloud ice, rain and falling snow)&lt;/p&gt;&#xA;&lt;p&gt;So how can I convert RH or SH to the humidity with unit 'mb'?&lt;/p&gt;&#xA;" OwnerUserId="22365" LastActivityDate="2021-09-23T20:01:30.177" Title="How to convert Relative humidity (%) or Specific humidity (kg/kg) to Air humidity (mb)?" Tags="|climatology|humidity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21179" PostTypeId="1" CreationDate="2021-04-24T17:51:31.030" Score="4" ViewCount="321" Body="&lt;p&gt;Disclaimer: I am not a scientist.&lt;/p&gt;&#xA;&lt;p&gt;I was wondering if there is a concern that the world will run out of breathable atmospheric oxygen as the number of dead zones in the ocean increases with global warming. This concern is based on the understanding that 60% (give or take) of our breathable oxygen is produced by phytoplankton. I have read a few peer reviewed articles to that effect, all by the same author, but haven't seen any articles that counter that concern.&lt;/p&gt;&#xA;" OwnerUserId="21456" LastActivityDate="2021-04-26T08:42:51.480" Title="As the number of ocean dead zones increases, is the world's primary source of atmospheric oxygen (phytoplankton) at risk?" Tags="|climate-change|oceanography|oxygen|geobiology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21181" PostTypeId="2" ParentId="21176" CreationDate="2021-04-24T18:23:09.093" Score="2" Body="&lt;p&gt;Probably not.&lt;/p&gt;&#xA;&lt;p&gt;The biological pathways to make lignin is the same in all plants so there is no reasons to believe they would be better. If anything modern trees as a whole may be better since they survive in  larger range of environments and very dense wooded trees exist. In addition without defenses against modern wood decomposers Carboniferous plants may have a hard time surviving in the modern world.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2021-04-24T18:23:09.093" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21182" PostTypeId="2" ParentId="21179" CreationDate="2021-04-24T18:57:51.983" Score="3" Body="&lt;p&gt;Yes, it is, though probably not immediately. Ocean and atmosphere deoxygenation is a thing, and many publications are out.&lt;/p&gt;&#xA;&lt;p&gt;In a larger context, deoxygenation is indeed inevitable even if we ignore anthropogenic warming. Increasing solar flux alone (the sun get's hotter over its lifespan) could reduce the atmospheric oxygen to 1% of present day level within around a billion years, says &lt;a href=&quot;https://www.nature.com/articles/s41561-021-00693-5&quot; rel=&quot;nofollow noreferrer&quot;&gt;this publication&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/s41467-021-22584-4&quot; rel=&quot;nofollow noreferrer&quot;&gt;This publication&lt;/a&gt; estimates that almost 80% of ocean deoxygenation under current day CO&lt;sub&gt;2&lt;/sub&gt; levels have not been realized yet, but they say that oceanic surface deoxygenation will stop once CO&lt;sub&gt;2&lt;/sub&gt; emissions stop, while the deep ocean oxygen levels will continue to decrease.&lt;/p&gt;&#xA;&lt;p&gt;A &lt;a href=&quot;http://link.springer.com/article/10.1007/s11538-015-0126-0&quot; rel=&quot;nofollow noreferrer&quot;&gt;global warming by 6°C&lt;/a&gt; (which is at the upper end of current projections until the end of this century) could tip the oxygen production by phytoplankton, cancelling the ocean's role as a main oxygen producer.&lt;/p&gt;&#xA;&lt;p&gt;Citing from the abstract:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;[...] If, in the course of time, the oxygen production rate becomes too low or too high, the system’s dynamics changes abruptly, resulting in the oxygen depletion and plankton extinction. Our results indicate that the depletion of atmospheric oxygen on global scale (which, if happens, obviously can kill most of life on Earth) is another possible catastrophic consequence of the global warming [...]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user22279" LastEditorDisplayName="user22279" LastEditDate="2021-04-26T08:42:51.480" LastActivityDate="2021-04-26T08:42:51.480" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21183" PostTypeId="1" CreationDate="2021-04-24T23:17:11.693" Score="4" ViewCount="79" Body="&lt;p&gt;I understand that without the solar wind, the Geomagnetic field would essentially be that of a dipole.&lt;/p&gt;&#xA;&lt;p&gt;With the presence of the solar wind, this field is distorted, as can be seen in many images that a quick online search will show.&lt;/p&gt;&#xA;&lt;p&gt;However, I am looking for the early mathematical descriptions of this model (with the solar wind distortion). I have found several papers from Tsyganenko (links attached below). I am curious to know if:&lt;/p&gt;&#xA;&lt;p&gt;a) this is the first attempt to describe this mathematically, or&lt;/p&gt;&#xA;&lt;p&gt;b) if not, is there any other information out there which would show how this model was developed?&lt;/p&gt;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;&lt;p&gt;Link to Tsyganenko material : &lt;a href=&quot;https://ccmc.gsfc.nasa.gov/modelweb/magnetos/tsygan.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://ccmc.gsfc.nasa.gov/modelweb/magnetos/tsygan.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22312" LastActivityDate="2021-06-03T13:05:25.570" Title="Derivation of Geomagnetic field lines (after interaction with solar wind)" Tags="|geomagnetism|magnetosphere|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21184" PostTypeId="2" ParentId="21161" CreationDate="2021-04-25T16:24:53.627" Score="5" Body="&lt;p&gt;To add some concrete data to some of the great answers already here:&lt;/p&gt;&#xA;&lt;p&gt;Seattle is actually not particularly rainy, especially compared to other parts of WA, but also compared to other cities in the US. According to &lt;a href=&quot;https://www.currentresults.com/Weather/US/average-annual-precipitation-by-city.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;this chart of the largest 51 US cities&lt;/a&gt;, Seattle is wetter than 18, drier than 31, and tied with 1. Yet, Seattle only has less rainy-days than 5 cities, and more rainy-days than 45 cities. This indicates that Seattle probably gets its rain as a constant drizzle (which seems confirmed from anecdotal evidence) which would allow for the area to store and drain water faster than it peaks.&lt;/p&gt;&#xA;&lt;p&gt;Interesting side-note:&lt;/p&gt;&#xA;&lt;p&gt;A unexpected city that does suffer from flash floods is Tucson, Arizona. It receives 11.6 inches (294.6 mm) of rain yearly and 2.4 inches (61 mm) in its peak month. It is, however, flat and apparently large parts of the city do not have storm sewers. Additionally, &lt;a href=&quot;https://www.azcentral.com/story/news/local/arizona/2014/08/21/12-news-arizona-desert-cant-absorb-water/14361963/&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Arizona habitat does not seem to naturally drain water very well&lt;/a&gt;. This shows the importance both of city planning and natural drainage, which I'm sure Seattle, a wet city, has both in plenty.&lt;/p&gt;&#xA;" OwnerUserId="22372" LastEditorUserId="7314" LastEditDate="2022-01-30T16:50:42.817" LastActivityDate="2022-01-30T16:50:42.817" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21186" PostTypeId="1" AcceptedAnswerId="21193" CreationDate="2021-04-26T07:08:30.280" Score="5" ViewCount="117" Body="&lt;p&gt;I would like to know how good the weather data coverage is on the surface of the world’s oceans, and how much it would improve climate research/models if weather observations from ocean-going vessels were made publicly available. As I understand the current situation, publicly available ocean weather data is mostly measured via stationary floats and satellites, where the satellites only measure temperature.&lt;/p&gt;&#xA;&lt;p&gt;Many ocean-going vessels measure sea temperature, air pressure + temperature and wind speed + direction. These vessels cover a fair bit of the ocean surface during their trips, and some vessels log these observations every hour or even more frequently.&lt;/p&gt;&#xA;&lt;p&gt;I have two questions relating to this:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Are there more publicly available sources of oceanic weather data&#xA;than the ones I list in the beginning?&lt;/li&gt;&#xA;&lt;li&gt;Would weather data from ocean-going vessels be beneficial to&#xA;climate research, by e.g. giving many additional calibration points for climate&#xA;models relating to ocean weather? Can you give examples of which specific&#xA;areas of research it would apply to? I’m thinking things like&#xA;ocean heat absorption and emission, hurricane formation and maybe&#xA;El Niño.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="22375" LastEditorUserId="22375" LastEditDate="2021-04-26T10:25:17.130" LastActivityDate="2021-04-27T16:08:24.360" Title="How much would weather data from ocean-going vessels improve climate research?" Tags="|meteorology|climate-change|climate-models|open-data|weatherdata|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21187" PostTypeId="2" ParentId="21178" CreationDate="2021-04-26T09:55:08.507" Score="1" Body="&lt;p&gt;I guess what you need is &lt;strong&gt;water vapour pressure&lt;/strong&gt; - that is one way of expressing humidity as the partial pressure of water vapour - in &lt;code&gt;mb&lt;/code&gt; or &lt;code&gt;hPa&lt;/code&gt; (they are equal).&lt;/p&gt;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://library.wmo.int/doc_num.php?explnum_id=10616&quot; rel=&quot;nofollow noreferrer&quot;&gt;World Meteorological Organization&lt;/a&gt; (&lt;em&gt;WMO No.8 Guide to Instruments and Methods of Observation, Vol 1 Measurement of Meteorological Variables, ANNEX 4.B. FORMULAE FOR THE COMPUTATION OF MEASURES OF HUMIDITY&lt;/em&gt;), saturation vapour pressure - &lt;code&gt;ews(t)&lt;/code&gt; - in &lt;strong&gt;hPa&lt;/strong&gt; may be derived by the following formula, where &lt;code&gt;t&lt;/code&gt; is temperature in &lt;strong&gt;degrees Celsius&lt;/strong&gt;:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;ews(t) = 6.112 exp [17.62 t/(243.12 + t)]   &#xA;&#xA;in hPa and degrees C, for liquid pure water (–45 °C to 60 °C)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;This is the &lt;strong&gt;saturation&lt;/strong&gt; water vapour pressure - a kind of &amp;quot;maximum&amp;quot; water vapour that can normally exist at a certain temperature &lt;code&gt;t&lt;/code&gt;.&lt;/p&gt;&#xA;&lt;p&gt;To know what the actual water vapour pressure - &lt;code&gt;ew(t)&lt;/code&gt; - is, you must multiply it by the relative humidity (&lt;strong&gt;Rh&lt;/strong&gt;) (and divide by 100 if &lt;code&gt;Rh&lt;/code&gt; is in percentage):&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;ew(t) = ews(t) * Rh(%) / 100&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;So,&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;ew(t) = 6.112 exp [17.62 t/(243.12 + t)] * Rh(%) / 100&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is your &amp;quot;humidity&amp;quot; in mb, if you use Celsius for &lt;strong&gt;t&lt;/strong&gt;.&lt;/p&gt;&#xA;" OwnerUserId="7916" LastEditorUserId="7916" LastEditDate="2021-04-26T19:01:12.220" LastActivityDate="2021-04-26T19:01:12.220" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21188" PostTypeId="1" CreationDate="2021-04-26T13:28:30.203" Score="1" ViewCount="219" Body="&lt;p&gt;Trying to truly understand high- and low-pressure systems, I find explanations contradicting.&#xA;&lt;strong&gt;The question is&lt;/strong&gt;: Where is the mistake in my line of thoughts?&lt;/p&gt;&#xA;&lt;p&gt;Looking from a surface point of view:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;More sun = more heat.&lt;/li&gt;&#xA;&lt;li&gt;More heat = higher ground pressure (just like heating a bottle)&lt;/li&gt;&#xA;&lt;li&gt;Higher ground pressure = Hot air wants to expend to all directions&lt;/li&gt;&#xA;&lt;li&gt;Expending air (also) the vertical axis = rising air, cloud formation.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;That is coherent with the notions&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;that high-pressure areas come from the equator while low-pressure areas come from the poles&lt;/li&gt;&#xA;&lt;li&gt;that there is a circulation of air rising around the equator and sinking at the poles.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;But it conflicts with the notion&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;that air sinks into high-pressure areas and&lt;/li&gt;&#xA;&lt;li&gt;hence high-pressure areas have fewer clouds than low-pressure areas.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;If I flip everything, that conflict is solved while suddenly global circulation and &amp;quot;H from Equator&amp;quot; doesn't fit into the picture.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, it seems that sometimes air sinks, creating the higher pressure underneath, and other times it starts with the high pressure and air rises. So I might assume that both high and low pressure can origin from both high and low temperatures, and at both, air can rise or fall. Or in other words: whatever, it's free-for-all.&lt;/p&gt;&#xA;&lt;p&gt;Where is my mistake?&lt;/p&gt;&#xA;" OwnerUserId="7774" LastActivityDate="2021-04-26T16:51:37.910" Title="Is surface temperature relevant for the creation of high- and low pressures areas?" Tags="|meteorology|pressure|cyclone|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21189" PostTypeId="1" CreationDate="2021-04-26T13:45:42.967" Score="1" ViewCount="102" Body="&lt;p&gt;How do you derive the components of the inertial advective wind in natural coordinates?&lt;/p&gt;&#xA;&lt;p&gt;The vector form of the inertial advective wind is:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Ec4LH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ec4LH.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I have been able to find the components in cartesian coordinates as shown here:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DNSkz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DNSkz.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I want to find the components in natural coordinates (such as shown below), but I have been unsuccessful so far.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3gpRu.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3gpRu.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Any help would be greatly appreciated! Thanks&lt;/p&gt;&#xA;" OwnerUserId="22378" LastActivityDate="2021-04-26T13:45:42.967" Title="How to find inertial advective component of ageostrophic wind in natural coordinates" Tags="|meteorology|wind|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21190" PostTypeId="2" ParentId="21188" CreationDate="2021-04-26T16:51:37.910" Score="1" Body="&lt;p&gt;Your logic is wrong. Do not think of the atmosphere as a closed system. Your analogy of heating a bottle is not appropriate.&lt;/p&gt;&#xA;&lt;p&gt;In uncomplicated terms, the Sun heats the ground, the ground radiates thermal energy heating the air just above the ground and the heated air rises. In rising, the air heated has less density than the surrounding air. By rising it exerts less pressure on the ground than the surrounding and thus has a lower pressure relative to the air surrounding it - it is a low pressure system.&lt;/p&gt;&#xA;&lt;p&gt;The rising air reaches the tropopause, around 10 to 15 km above sea level, where it is no longer buoyant. Forced by the continually rising air it travels away from the heated zone. As it moves at such elevations  the air cools, increases in density and falls to the ground. As it falls the pressure it exerts on the ground is higher than the air surrounding it and it forms a high pressure system.&lt;/p&gt;&#xA;&lt;p&gt;The system is best explained with &lt;a href=&quot;https://en.wikipedia.org/wiki/Hadley_cell&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hadley Cells&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Air tends to rise around the equator and at latitudes 60° north and south, where most of the low pressure systems are located. Air tends to fall around latitude 30° north and south and the poles, where most of the high pressure systems are located.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-04-26T16:51:37.910" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21192" PostTypeId="1" CreationDate="2021-04-27T15:18:55.960" Score="4" ViewCount="39" Body="&lt;p&gt;I found this image of an electron density profile.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;ftp://ftp.ngdc.noaa.gov/ionosonde/data/RO041/individual/2021/046/image/RO041_2021046113000_EDP.PNG&quot; rel=&quot;nofollow noreferrer&quot;&gt;ftp://ftp.ngdc.noaa.gov/ionosonde/data/RO041/individual/2021/046/image/RO041_2021046113000_EDP.PNG&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, the profile is expressed in terms of &amp;quot;plasma frequency&amp;quot; and not in terms of electron density which I assume would be something like electron/m&lt;sup&gt;3&lt;/sup&gt;.&#xA;Why is it so?&#xA;Is there a one to one relationship with electron density?&lt;/p&gt;&#xA;" OwnerUserId="21271" LastEditorUserId="2470" LastEditDate="2021-04-27T17:32:51.127" LastActivityDate="2021-04-27T17:32:51.127" Title="Ionosonde.Why are electron density profile expressed in plasma frequency?" Tags="|ionosphere|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21193" PostTypeId="2" ParentId="21186" CreationDate="2021-04-27T16:08:24.360" Score="5" Body="&lt;p&gt;&amp;quot;Ship of opportunity&amp;quot; weather observations have contributed to global data collection exercises since the dawn of meteorology as a science. There are many national and international initiatives that collect data and the data already inform weather forecasts and climate models. The practice is summarised in &lt;a href=&quot;https://www.frontiersin.org/articles/10.3389/fmars.2019.00434/full&quot; rel=&quot;noreferrer&quot;&gt;https://www.frontiersin.org/articles/10.3389/fmars.2019.00434/full&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;In recent years the number of ships contributing has declined, but over 2000 ships that do participate are collecting higher quality data.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2021-04-27T16:08:24.360" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21194" PostTypeId="2" ParentId="21147" CreationDate="2021-04-28T07:01:14.657" Score="3" Body="&lt;p&gt;You mention &amp;quot;volume&amp;quot; which is the crux of the problem: the surface mixing layer changes height throughout the day as solar heating influences the surface.  Consider that the same emission rate can cause different concentrations at different heights and at different times of day and year.  Meteorology drives all mixing and deposition, so whatever you use to parameterize meteorology will influence the numerical limits of your solution.  Applications for calculating concentrations from emissions rates vary in their methods considerably, depending on the purpose and spatiotemporal coverage of your input data.&lt;/p&gt;&#xA;&lt;p&gt;Here are some examples of applications that use vehicle emissions rates as inputs, to calculate atmospheric concentrations, going from smallest to largest spatial scale:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The basics - use a &lt;a href=&quot;https://www.sciencedirect.com/topics/engineering/box-model&quot; rel=&quot;nofollow noreferrer&quot;&gt;box model&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Roadway dispersion model such as &lt;a href=&quot;https://www.epa.gov/state-and-local-transportation/new-r-line-additions-aermod-19191-refined-transportation-projects&quot; rel=&quot;nofollow noreferrer&quot;&gt;AERMOD with RLINE&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Gridded chemical transport model, such as the &lt;a href=&quot;https://www.cmascenter.org/smoke/&quot; rel=&quot;nofollow noreferrer&quot;&gt;WRF/SMOKE/CMAQ&lt;/a&gt; suite (suitable for &amp;quot;city&amp;quot; predictions)&lt;/li&gt;&#xA;&lt;li&gt;Global chemical transport model, such as &lt;a href=&quot;http://acmg.seas.harvard.edu/geos/&quot; rel=&quot;nofollow noreferrer&quot;&gt;GEOS-CHEM&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="543" LastActivityDate="2021-04-28T07:01:14.657" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21195" PostTypeId="1" CreationDate="2021-04-29T01:17:02.813" Score="0" ViewCount="34" Body="&lt;p&gt;I want to see the anthropogenic influence of one region(source)  to another region(receptor). I would be conducting nested grid simulation. But,  the nested grid simulation will be limited to receptor region only. The boundary conditions will be given by a more coarser resolution.&lt;/p&gt;&#xA;&lt;p&gt;So what will be the difference in result if I turned of emission from source with source lying outside or inside the Nested grid domain when the boundary condition is from coarser resolution? How much of a difference will it make?&lt;/p&gt;&#xA;" OwnerUserId="20906" LastEditorUserId="20906" LastEditDate="2021-04-29T12:55:17.757" LastActivityDate="2021-04-29T12:55:17.757" Title="Difference in values if the source region lies outside or within the nested grid domain with boundary conditions from coarser resolution" Tags="|atmosphere-modelling|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21196" PostTypeId="1" CreationDate="2021-04-29T20:15:25.453" Score="5" ViewCount="153" Body="&lt;p&gt;Papers like &lt;a href=&quot;https://pubmed.ncbi.nlm.nih.gov/20970394/&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/0895717794901880&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;, etc. and the work of Axel Kleidon (e.g. &lt;a href=&quot;https://royalsocietypublishing.org/doi/10.1098/rspb.1987.0067&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;) suggest that the the biosphere increases the production of entropy of Earth but I'd like to know if we could quantify this in a simple way. What would the entropy production be without life? If we knew that then the difference between what it is estimated to be would be easy to calculate.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://royalsocietypublishing.org/doi/10.1098/rspb.1987.0067&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ulanowicz, R.E. and Hannon, B.M., 1987&lt;/a&gt;. Life and the production of entropy. Proceedings of the Royal society of London. Series B. Biological sciences, 232(1267), pp.181-192.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/0895717794901880&quot; rel=&quot;nofollow noreferrer&quot;&gt;Schneider, E.D. and Kay, J.J., 1994&lt;/a&gt;. Life as a manifestation of the second law of thermodynamics. Mathematical and computer modelling, 19(6-8), pp.25-48.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://pubmed.ncbi.nlm.nih.gov/20970394/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kleidon, A., 2010&lt;/a&gt;. Life, hierarchy, and the thermodynamic machinery of planet Earth. Physics of life reviews, 7(4), pp.424-460.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="22395" LastEditorUserId="-1" LastEditDate="2021-05-08T11:39:38.897" LastActivityDate="2021-05-08T11:39:38.897" Title="How much does the biosphere contribute to Earth's entropy production?" Tags="|planetary-science|earth-system|thermodynamics|energy-balance|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="21197" PostTypeId="1" CreationDate="2021-04-30T03:14:32.483" Score="4" ViewCount="263" Body="&lt;p&gt;This &lt;a href=&quot;https://earthscience.stackexchange.com/a/21109/6031&quot;&gt;answer to &lt;em&gt;Would a gold-containing meteor cause it to “rain” gold?&lt;/em&gt;&lt;/a&gt; says (in part):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Meteors, when in space, are very very &lt;strong&gt;very &lt;em&gt;very&lt;/em&gt;&lt;/strong&gt; cold. Their travel duration in Earth's atmosphere is very short, just a couple of seconds. Actual melting only occurs at the very most outer layer of the meteorite. This is not sufficient to heat up the interior of the meteorite to any significant degree. In fact, some meteorite falls have found to have frost on them when found soon after landing, because they condense the moisture in the air around them!&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The &amp;quot;very very &lt;strong&gt;very &lt;em&gt;very&lt;/em&gt;&lt;/strong&gt;&amp;quot; might be overstated, but let's see if they could be below the freezing point of water.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Planetary_equilibrium_temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;surface temperature of an asteroid&lt;/a&gt; can be applied to roughly spherical objects of arbitrary size, there's no scale in the derivation; it should work for centimeter-sized objects as well as it would for a planet sized rocky object &lt;em&gt;sans atmosphere&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$T^4 = \frac{L_0 (1-A)}{\epsilon \sigma 16 \pi a^2 }$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here &lt;span class=&quot;math-container&quot;&gt;$L_0$&lt;/span&gt; is the total &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_luminosity&quot; rel=&quot;nofollow noreferrer&quot;&gt;solar luminosity&lt;/a&gt; of 3.827×10&lt;sup&gt;26&lt;/sup&gt; W and &lt;span class=&quot;math-container&quot;&gt;$\sigma$&lt;/span&gt; is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_constant&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stefan-Boltsman constant&lt;/a&gt; 5.67×10&lt;sup&gt;-8&lt;/sup&gt; W/m&lt;sup&gt;2&lt;/sup&gt;/K&lt;sup&gt;4&lt;/sup&gt;. &lt;span class=&quot;math-container&quot;&gt;$a$&lt;/span&gt; is the distance from the Sun, let's assume that the meteor has been near 1 AU long enough (weeks) to reach equilibrium temperature. &lt;span class=&quot;math-container&quot;&gt;$\epsilon$&lt;/span&gt; is the asteroid's infra-red emissivity and a value of 0.9 is given as typical.&lt;/p&gt;&#xA;&lt;p&gt;The ~visible light average albedo &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; of asteroids is the big variable here. They are usually pretty dark but there is a lot of variation and measurements are often based on other assumptions. I'll calculate the equilibrium temperature for a few, but as one can guess 1 minus a small number is close to 1, and after you take the fourth root, it's very close to 1!&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;Albedo    Temperature&#xA;(vis)       K     C&#xA; 0.05     282     8&#xA; 0.10     278     5&#xA; 0.2      270    -3&#xA; 0.5      240    -33&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;So for a meteor to be &lt;em&gt;even barely below&lt;/em&gt; the freezing point of water it would have to have an &lt;em&gt;above-average albedo&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;It seems to me that after &lt;a href=&quot;https://astronomy.stackexchange.com/a/38912/7982&quot;&gt;tens of seconds to minutes&lt;/a&gt; there is not enough time for the transient heat pulse on the skin to do more than melt the surface, but the radiative heating from the plasma created for larger meteors can be quite intense, so they sometimes &amp;quot;explode&amp;quot; or breakup due to stress.&lt;/p&gt;&#xA;&lt;p&gt;Nonetheless the core temperatures of larger meteorites reaching the surface could very well reflect the temperature in space.&lt;/p&gt;&#xA;&lt;p&gt;So a meteorite becoming &amp;quot;frosty&amp;quot; soon after landing is plausible if it were of a higher than average albedo.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Have &amp;quot;frosty meteorites&amp;quot; ever been observed soon after landing? Are there photos?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Related:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://astronomy.stackexchange.com/q/38909/7982&quot;&gt;How long between the moment a meteor is first visible and the moment a meteorite hits the ground?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://astronomy.stackexchange.com/q/23615/7982&quot;&gt;How much time does it take for a meteor (shooting star) to touch the ground after its combustion?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://astronomy.stackexchange.com/q/35984/7982&quot;&gt;How complicated is the heating of meteors?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/127/6031&quot;&gt;What temperature do small meteorites have on impact&lt;/a&gt; there are answers posted but no temperatures... &lt;em&gt;yet!&lt;/em&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/14864/6031&quot;&gt;Is it possible to estimate the size of a meteorite from its remains?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/42qhl.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/42qhl.png&quot; alt=&quot;Asteroid albedos: graphs of data by Wm. Robert Johnston last updated 25 March 2017&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; From &lt;a href=&quot;http://www.johnstonsarchive.net/astro/astalbedo.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Asteroid albedos: graphs of data by Wm. Robert Johnston last updated 25 March 2017&lt;/a&gt; &lt;strong&gt;below:&lt;/strong&gt; From NYTimes' &lt;a href=&quot;https://www.nytimes.com/2021/04/29/science/meteorite-botswana-asteroid.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;A 22-Million-Year Journey From the Asteroid Belt to Botswana&lt;/a&gt; &amp;quot;A fragment of the asteroid 2018 LA, found in the Central Kalahari Game Reserve in Botswana in 2018.Credit...P. Jenniskens/SETI Institute&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;This is what got me thinking about this topic&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cUWcZ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cUWcZ.png&quot; alt=&quot;A fragment of the asteroid 2018 LA, found in the Central Kalahari Game Reserve in Botswana in 2018.Credit...P. Jenniskens/SETI Institute&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;For comparison:&lt;/strong&gt; from &lt;a href=&quot;https://space.stackexchange.com/a/24660/12102&quot;&gt;this answer to &lt;em&gt;Who discovered “Egg Rock”? The Curiosity rover or people?&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;...Cropped section of image of &amp;quot;Egg Rock&amp;quot; from &lt;a href=&quot;http://redplanet.asu.edu/?p=21047&quot; rel=&quot;nofollow noreferrer&quot;&gt;redplanet.asu.edu/?p=21047&lt;/a&gt; showing the spots where Curiosity's ChemCam laser has ablated material.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KJ2nK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KJ2nK.jpg&quot; alt=&quot;Egg rock on Mars showing the spots where Curiosity's ChemCam laser has ablated material.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Spoiler alert:&lt;/p&gt;&#xA;&lt;blockquote class=&quot;spoiler&quot;&gt;&#xA;&lt;p&gt; &lt;strong&gt;People did!&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2021-04-30T06:52:20.100" LastActivityDate="2021-04-30T06:52:20.100" Title="Have &quot;frosty meteorites&quot; ever been observed soon after landing? Are there photos?" Tags="|atmosphere|meteorite|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="21198" PostTypeId="1" CreationDate="2021-04-30T12:43:18.623" Score="2" ViewCount="534" Body="&lt;p&gt;Answers to my previous question &lt;a href=&quot;https://earthscience.stackexchange.com/q/19151/6031&quot;&gt;How is relative humidity determined from a wet and dry bulb readings?&lt;/a&gt; provide equations for converting the two temperature measurements to a relative humidity.&lt;/p&gt;&#xA;&lt;p&gt;In comments under &lt;a href=&quot;https://earthscience.stackexchange.com/q/21197/6031&quot;&gt;this question&lt;/a&gt; I have heard of a &lt;a href=&quot;https://www.preservationequipment.com/Catalogue/Instruments/Hygrometers/Whirling-Hygrometer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Whirling Hygrometer&lt;/a&gt; which seems to be the same basic beast (two thermometers, one with a wet bulb from a cotton sock and small reservoir) but like the name says, this one you have to &amp;quot;whirl&amp;quot; around for most of a minute; presumably the evaporation is more efficient in the blowing air.&lt;/p&gt;&#xA;&lt;p&gt;But I don't understand if that leads to a lower cold temperature and therefore requires a different equation, nor if the speed that it is whirled makes a difference. And I'm not sure &lt;em&gt;why&lt;/em&gt; whirling is used if the static non-whirled kind also can be used, without moving parts.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; How does a whirling hygrometer work, how does it differ from static dry/wet bulb thermometer, and how to obtain humidity from its readings?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Related:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/19152/6031&quot;&gt;How do the pros measure humidity?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/19145/6031&quot;&gt;What is the second thermometer in the image from the Esperanza Antarctic temperature record?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/15349/6031&quot;&gt;How is the specific heat of a wet bulb determined?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Yu941.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Yu941m.jpg&quot; alt=&quot;wet/dry bulb humidity measurement&quot; /&gt;&lt;/a&gt; click for larger&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2021-05-02T01:21:09.537" Title="How does a whirling hygrometer work, how does it differ from static dry/wet bulb thermometer, and how to obtain humidity from its readings?" Tags="|meteorology|measurements|humidity|instrumentation|field-measurements|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="21199" PostTypeId="2" ParentId="4320" CreationDate="2021-05-01T10:43:50.993" Score="2" Body="&lt;p&gt;The semi-enclosed body of water can probably be called a reef lagoon.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://link.springer.com/referenceworkentry/10.1007%2F3-540-31060-6_202&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://link.springer.com/referenceworkentry/10.1007%2F3-540-31060-6_202&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A coral reef lagoon is that body of water that lies within an atoll (annular) reef or within a barrier reef. It is generally assumed that an appreciable depth of water is maintained within the lagoon, say 5-50 meters. Those reef platforms which have some shallow pools a few feet deep that show up especially at low tide have sometimes been called pseudoatolls or pseudatolls, and their pools thus “pseudolagoons” or “miniature lagoons,” but these terms are not recommended. The miniature lagoon of a faro (q.v.) is termed a “velu.” The terms “moat” or “lagoonlet” are often used for pools on platform reefs.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.britannica.com/science/lagoon-geography#ref233794&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.britannica.com/science/lagoon-geography#ref233794&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Coral lagoons are restricted to tropical open seas that provide the conditions necessary for coral growth. They are best exemplified by the roughly circular quiet waters that are surrounded by warm-water coral atoll reefs. Coral lagoons occur widely in the western Pacific, in parts of the Indian Ocean, and in isolated places in the Caribbean, mainly within 25° latitude of the Equator. Coral lagoons are of great importance to many island communities in the Pacific, particularly where they provide the only quiet water for use as harbours, although the passage through the reef into the lagoon is often perilous.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="22400" LastEditorUserId="6031" LastEditDate="2021-05-02T02:07:27.610" LastActivityDate="2021-05-02T02:07:27.610" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21201" PostTypeId="2" ParentId="21198" CreationDate="2021-05-01T22:35:33.833" Score="3" Body="&lt;p&gt;Instead of «whirling thermometer» you probably refer to «&lt;a href=&quot;https://en.wikipedia.org/wiki/Hygrometer#Sling_psychrometer&quot; rel=&quot;nofollow noreferrer&quot;&gt;sling psychrometer&lt;/a&gt;» consisting of a dry-bulb thermometer and a wet-bulb thermometer.  Yet, different to a static wet-bulb thermometer shown in the question, the constant rotation of the two thermometers permits evaporation from the wet cloth around the web bulb thermometer to «pristine parts» of surrounding air.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/euwN4.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/euwN4.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(&lt;a href=&quot;https://automationforum.co/what-is-a-sling-psychrometer-limitations-application-working/&quot; rel=&quot;nofollow noreferrer&quot;&gt;credit&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;If the air around the wet-bulb thermometer is less than water saturated, the temperature of shown on the wet-bulb thermometer will be lower than the one read on the dry-bulb thermometer.  The swirling motion aims to expose the wet-bulb thermometer to air which was not yet in contact with the former.  Thus, both recordings allow you to report both (dry) temperature, dew temperature, and humidity of the air.&lt;/p&gt;&#xA;&lt;p&gt;A beginner's introduction is equally given &lt;a href=&quot;https://www.youtube.com/watch?v=OB0_yM8g0nM&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, a computation chart relating the temperature difference read (one for the Celsius, an other for the Fahrenheit scale) to the relative humidity &lt;a href=&quot;https://www.tqcsheen.com/en/product/sling-psychrometer-en/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Suggested by user &lt;code&gt;@uhoh&lt;/code&gt;, it is worth to set the quality of the readings obtained with this instrument into a context.&#xA;The 1993 edition of &lt;a href=&quot;https://www.nps.gov/museum/publications/conserveogram/03-01.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Conserve O Gram 3/1&lt;/a&gt; (accessed from the series' program &lt;a href=&quot;https://www.nps.gov/museum/publications/conserveogram/cons_toc.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;overview&lt;/a&gt;) mentions «These instruments are accurate to &lt;span class=&quot;math-container&quot;&gt;$\pm \pu{2\% RH}$&lt;/span&gt; when properly maintained and operated by trained and practiced users.»  Equally, the guide reminds to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Clausius%E2%80%93Clapeyron_relation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Clausius-Clapeyron relation&lt;/a&gt; when stating:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;«Psychrometers and psychrometric charts are intended for use within a certain range of atmospheric pressure. High altitude, above 900 m (approx. 3,000 ft), will directly affect the accuracy of the RH reading unless a pressure correction formula is applied or a psychrometric chart or slide rule for the appropriate pressure is used. For further information see Ann Hitchcock and Gordon C. Jacoby, “Measurement of Relative Humidity in Museums at High Altitude,” Studies in Conservation 25 (1980): pp. 78-86. (Copies are available to NPS sites from Curatorial Services Division, Harpers Ferry office.»&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;A study by &lt;a href=&quot;https://doi.org/10.1007/s10765-007-0293-9&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wang and Tang&lt;/a&gt; /  Singapore's metrology centre published by 2007 mentions:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;«... that although the psychrometer coefficient of a particular psychrometer can be quite consistent with long-term stability typically within the range of  ± 1% rh equivalent, there are larger variations (up to 4% rh equivalent) among different psychrometers even of the same type.»&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="18990" LastEditorUserId="18990" LastEditDate="2021-05-02T01:21:09.537" LastActivityDate="2021-05-02T01:21:09.537" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21203" PostTypeId="1" AcceptedAnswerId="21206" CreationDate="2021-05-02T14:32:31.350" Score="1" ViewCount="88" Body="&lt;p&gt;I read some articles and news from various sources that the Arctic ozone hole has recovered. Some people claim that less emission of harmful gases due to covid-19 made this happen. AFAIK, the past few decades regulating and banning emission of CFCs and other harmful gases should have contributed to this.&lt;/p&gt;&#xA;&lt;p&gt;But &lt;a href=&quot;https://public.wmo.int/en/media/news/arctic-ozone-depletion-reached-record-level&quot; rel=&quot;nofollow noreferrer&quot;&gt;Some articles&lt;/a&gt; says that polar vortexes contribute to the change of the Ozone layer. It is a fact that CFCs and other ozone-depleting gases react with the Ozone layer and damage it.&lt;/p&gt;&#xA;&lt;p&gt;My question is for the arctic/antarctic Ozone holes, do polar vortexes contribute more?&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;PS: &lt;a href=&quot;https://expolk.online/technology/%E0%B6%85%E0%B6%9A%E0%B7%8A%E0%B6%A7%E0%B7%92%E0%B6%9A%E0%B7%8A-%E0%B6%85%E0%B6%BB%E0%B7%8A%E0%B6%B0%E0%B6%BA%E0%B7%9A-%E0%B6%94%E0%B7%83%E0%B7%9D%E0%B6%B1%E0%B7%8A-%E0%B7%83%E0%B7%92%E0%B6%AF/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This&lt;/a&gt; article in the Sinhala language made me ask this question. If you like, translate and read.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="20986" LastEditorUserId="2470" LastEditDate="2021-05-03T05:05:03.160" LastActivityDate="2021-05-03T05:05:03.160" Title="Are the polar vortexes main cause of ozone hole?" Tags="|ozone|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21204" PostTypeId="2" ParentId="2715" CreationDate="2021-05-02T19:45:48.077" Score="2" Body="&lt;p&gt;Where all that nitrogen comes from.&#xA;The two terrestrial planets plus one moon, in order of the amount of Nitrogen that they possess in their atmospheres: are Venus, Titan, finally Earth. Our planet is last. Everyone seems to not understand the difference between quantity and percentage. Venus has an atmospheric pressure of 92 bars, unlike Earth's of one bar at sea level. This means that at 3.5 % Venus has at least more than double the amount of nitrogen than Earth in its atmosphere. Saturn's moon Titan has an atmosphere mainly of nitrogen with a hint of methane. Nasa reports that its atmosphere is four times as dense as ours and Wikipedia says Titan's surface pressure is 1.5 bar. Again, Titan has more nitrogen than Earth. What is startling is the non-effect of gravity on atmospheric density. What do all three have in common that Mars lacks? Magnetic protective fields. No Venus does not have an intrinsic magnetic field but the solar wind induces one in its atmosphere. Saturn does the same thing for Titan. I would suggest that ionized nitrogen from the solar wind or the magnetosphere of Saturn would be deposited on these two planets and a single planetoid. Once there and relatively protected from charged particles and radiation, nitrogen is enough of an inert gas to accumulate over time. Just as water does in the Plasma Water Theory on Earth. &lt;a href=&quot;https://www.researchgate.net/publication/349685226_plasma_water_theory&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/publication/349685226_plasma_water_theory&lt;/a&gt; I could definitely be wrong here, but I would love to know how.&lt;/p&gt;&#xA;" OwnerUserId="22406" LastActivityDate="2021-05-02T19:45:48.077" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21205" PostTypeId="1" AcceptedAnswerId="21209" CreationDate="2021-05-02T23:54:27.250" Score="2" ViewCount="749" Body="&lt;p&gt;I would like to get some &lt;a href=&quot;https://en.wikipedia.org/wiki/Trinitite&quot; rel=&quot;nofollow noreferrer&quot;&gt;trinitite&lt;/a&gt; for my rock and mineral collection. The problem is that there is apparently a lot of fake trinitite for sale in the internet.&lt;/p&gt;&#xA;&lt;p&gt;How do I avoid the fakes, and be sure I purchase real trinitite?&lt;/p&gt;&#xA;" OwnerUserId="18975" LastEditorUserId="18990" LastEditDate="2021-05-03T14:02:18.887" LastActivityDate="2021-05-04T04:46:02.227" Title="Avoiding fake trinitite" Tags="|mineralogy|minerals|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21206" PostTypeId="2" ParentId="21203" CreationDate="2021-05-03T01:58:41.520" Score="3" Body="&lt;p&gt;To blame ozone destruction on the polar vortex would be like blaming trees for surface ozone production downwind of cities. Yes, nature is involved in the process, but nature is not the source of the catalytic pollutant that caused large change in ozone concentrations.&lt;/p&gt;&#xA;&lt;p&gt;The polar vortex is a naturally occurring meteorological phenomena that has occurred for millions of years, and the ozone layer was fine.  The issue is man-made halogenated compounds that catalytically destroy ozone (e.g. CFCs) when polar stratospheric clouds (PSCs) form.  The stronger the polar vortex, the colder it is and the longer the PSCs stick around, allowing more destruction of ozone.  The continental ice sheet over the south pole allows extremely cold temperatures, and so PSCs have been more prevalent there. Typically the Antarctic circle is much colder than the Arctic, so ozone destruction has been more prevalent in the southern hemisphere.  However, polar stratospheric clouds are occurring with &lt;a href=&quot;https://www.nasa.gov/multimedia/imagegallery/image_feature_680.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;increasing frequency in the Arctic&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I suppose you could argue that if there were no polar vortices, the ozone layer would not be so susceptible to CFCs.  However, the polar vortex and associated PSCs is a natural phenomena we cannot avoid.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2021-05-03T02:51:36.497" LastActivityDate="2021-05-03T02:51:36.497" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21209" PostTypeId="2" ParentId="21205" CreationDate="2021-05-03T09:25:11.923" Score="4" Body="&lt;p&gt;You will probably never know for sure, but the only way to get any confidence is to have any potential specimens analyzed by a mineralogical laboratory that can do Gamma spectroscopy.&lt;/p&gt;&#xA;&lt;p&gt;Fake &lt;a href=&quot;https://en.wikipedia.org/wiki/Trinitite&quot; rel=&quot;nofollow noreferrer&quot;&gt;trinitite&lt;/a&gt;,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;use a variety of means to achieve the glassy green silica look as well as mild radioactivity; however, only trinitite from a nuclear explosion will contain certain neutron activation products that are not found in naturally radioactive ores and minerals. Gamma spectroscopy can narrow down the potential nuclear explosions from which the material formed.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.minresco.com/trinitite/trinpopup.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Also&lt;/a&gt;,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;If it's too green, too translucent or too inexpensive to be true, it probably isn't real Trinitite!  So how does the collector know if a specimen is authentic?  Well, usually the only means for the collector to eliminate the fake stuff is to use a sensitive dosimeter and take a reading to verify that residual induced radiation exists.  This will be very small, but it can be detected.  This will not rule out the possibility that clever fakers will not add some small amount of weakly radioactive material to their formula.  The only way to be 100% certain of authenticity is by means of nuclear energy spectroscopy.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;One of the radioactive elements to test for is Cesium 137,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This radionuclide has a half life of 30.2 years and is one of several unique byproducts of nuclear fission or atomic detonations.  It is present in all authentic Trinitite specimens.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;All radioactive elements have a half life. The radioactive elements produced by the Trinity Test on 16 July 1945 are also well know. To increase the confidence of testing, the amount of each radionuclide in each sample would need to be detected and compared with the expected amount that would be in true Trinitite given the elapsed time since 16 July 1945.&lt;/p&gt;&#xA;&lt;p&gt;If the specimens have a report from testing laboratory, get a copy of the report and verify it with the laboratory. Ideally, such reports should had a picture of the sample that was tested. If so, ensure it matches what is being offered for sale.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-05-04T04:46:02.227" LastActivityDate="2021-05-04T04:46:02.227" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="21211" PostTypeId="1" AcceptedAnswerId="21214" CreationDate="2021-05-04T05:40:17.343" Score="1" ViewCount="257" Body="&lt;p&gt;I am working on the global CO&lt;sub&gt;2&lt;/sub&gt; emission using a model dataset. The model provides the CO&lt;sub&gt;2&lt;/sub&gt; emission in mol m&lt;sup&gt;-2&lt;/sup&gt; s&lt;sup&gt;-1&lt;/sup&gt;. How to convert mol m&lt;sup&gt;-2&lt;/sup&gt; s&lt;sup&gt;-1&lt;/sup&gt; CO&lt;sub&gt;2&lt;/sub&gt; emission to Megaton day&lt;sup&gt;-1&lt;/sup&gt; (Mt per day)?&lt;/p&gt;&#xA;&lt;p&gt;Regards&lt;/p&gt;&#xA;" OwnerUserId="22420" LastEditorUserId="2470" LastEditDate="2021-05-04T09:01:20.077" LastActivityDate="2021-05-04T15:58:23.487" Title="How to convert mol m-2 s-1 CO2 emission to Megaton day-1 (MtCO2 per day)?" Tags="|climate-models|co2|greenhouse-gases|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21212" PostTypeId="2" ParentId="21183" CreationDate="2021-05-04T12:10:54.497" Score="2" Body="&lt;p&gt;Short answer: Tsyganenko was not the first to attempt an observation based mathematical model, and older purely theoretical models also exist.&lt;/p&gt;&#xA;&lt;p&gt;The first mathematical magnetic field model was created from measurements made on Earth's surface by Carl Friedrich Gauss in the 1830s, when he derived the mathematical techniques we still use. For the solar wind and interactions between the Earth's field and the solar wind, we're talking the advent of the space age when we were first able to make measurements out in space and begin to mathematically describe them, though the idea of the solar wind had been suggested (not by that name) in the early 1900s, and theoretical models exist from the 1960s at least.&lt;/p&gt;&#xA;&lt;p&gt;Wikipedia has a brief summary of the history of major &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnetosphere#History&quot; rel=&quot;nofollow noreferrer&quot;&gt;magnetospheric&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_wind#History&quot; rel=&quot;nofollow noreferrer&quot;&gt;solar wind&lt;/a&gt; discoveries, that suggests things kicked off with satellite measurements made in 1958/9. Tsyganenko cites a &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JA080i004p00523&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA study from 1975&lt;/a&gt; as the first empirical model of Earth's magnetosphere and its interaction with the solar wind, though direct measurements apparently weren't made in the magneto-tail until 1983 (from the first Wiki page).&lt;/p&gt;&#xA;&lt;p&gt;An aside for clarity: the dipolar nature of Earth's magnetic field isn't due to the interaction with the solar wind - the field generated by the geodynamo in Earth's outer core contributes the bulk of Earth's magnetosphere and has a more complicated shape when considered at the Earth's surface, for example.&lt;/p&gt;&#xA;&lt;p&gt;Magnetic fields have a strong dependence on distance from their source, and smaller spatial features attenuate more rapidly (think like with sound waves - you hear low frequencies far away, but the high frequencies attenuate more quickly), so the approximation as a dipole gets more accurate as you move further away from the source of the field.&lt;/p&gt;&#xA;&lt;p&gt;So when considering the interaction between the solar wind and Earth's field, which occurs at several Earth radii out in space (the exact distance changes as it depends on the strength of Earth's field pushing out, and the strength of the solar wind pushing back) the Earth's field is roughly dipolar, and then gets distorted with a squashed bow-shock and elongated magneto-tail by the action of the solar wind.&lt;/p&gt;&#xA;" OwnerUserId="14123" LastEditorUserId="14123" LastEditDate="2021-05-04T13:03:34.103" LastActivityDate="2021-05-04T13:03:34.103" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21213" PostTypeId="1" CreationDate="2021-05-04T13:35:28.690" Score="1" ViewCount="651" Body="&lt;p&gt;I was given a problem in a competitive exam from previous year:&lt;/p&gt;&#xA;&lt;p&gt;Calculate the rate of change of temperature of the Earth's troposphere with pressure (&lt;span class=&quot;math-container&quot;&gt;$\frac{dT}{dP}$&lt;/span&gt;), given&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Scale height, &lt;span class=&quot;math-container&quot;&gt;$H$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$P(\text{H}) = (\frac{1}{e}\cdot P_0) = 8\text{ km}$&lt;/span&gt; (the geopotential height where the pressure equals to &lt;span class=&quot;math-container&quot;&gt;$\frac{1}{e}$&lt;/span&gt; of the initial one)&lt;/li&gt;&#xA;&lt;li&gt;Lapse rate &lt;span class=&quot;math-container&quot;&gt;$= \gamma= 6.5 \frac{°C}{km}$&lt;/span&gt; (change of temperature with height)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I tried using potential temperature equation and pressure profile equation, but I am not able to connect it.&lt;/p&gt;&#xA;&lt;p&gt;Please help me or just give an advice. Thank you!&lt;/p&gt;&#xA;" OwnerUserId="22424" LastEditorUserId="6298" LastEditDate="2021-05-08T14:19:58.567" LastActivityDate="2021-08-08T21:41:16.910" Title="How to calculate rate of change of temperature with pressure in Earth's troposhere?" Tags="|meteorology|atmosphere|climate|temperature|pressure|" AnswerCount="1" CommentCount="16" ContentLicense="CC BY-SA 4.0" />
  <row Id="21214" PostTypeId="2" ParentId="21211" CreationDate="2021-05-04T14:42:16.257" Score="1" Body="&lt;p&gt;Do the calculation for 1 mol of CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;1 mol of CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; weighs 49 grammes = 0.0049 kg&lt;/p&gt;&#xA;&lt;p&gt;86400 seconds in a day, so 864000 * 0.0049 = 423.36 kg/day/m&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The surface area of the globe is 5.1 x 10&lt;span class=&quot;math-container&quot;&gt;$^{14}$&lt;/span&gt; m&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt; - so 423.6 * 5.1 x 10&lt;span class=&quot;math-container&quot;&gt;$^{14}$&lt;/span&gt; = 2.16 x 10&lt;span class=&quot;math-container&quot;&gt;$^{17}$&lt;/span&gt; kg/day&lt;/p&gt;&#xA;&lt;p&gt;Convert from kg to Megatons, 10&lt;span class=&quot;math-container&quot;&gt;$^9$&lt;/span&gt; kg in a Megaton  - so we get 1 mol CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;/m&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt;/second = 2.16 x 10&lt;span class=&quot;math-container&quot;&gt;$^8$&lt;/span&gt; Megatons/day&lt;/p&gt;&#xA;&lt;p&gt;This assumes, as farrenthorpe commented, that the molar emission rate represents a rate evenly distributed over the globe - if, for instance it only represented terrestrial emissions, or emissions in a particular region the calculation would need to take that into account.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastEditorUserId="21672" LastEditDate="2021-05-04T15:58:23.487" LastActivityDate="2021-05-04T15:58:23.487" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21215" PostTypeId="1" CreationDate="2021-05-04T20:12:58.553" Score="3" ViewCount="68" Body="&lt;p&gt;Should humans explore the deep ocean (1800meters or deeper) or is this the realm of AUVs (Autonomous Underwater Vehicles)?&lt;/p&gt;&#xA;&lt;p&gt;It seems that such deep ocean exploration is best done by AUVs. They are easier to build, cheaper to maintain, less expensive service life, longer bottom times.&lt;/p&gt;&#xA;&lt;p&gt;I'm curious how humans can best provide value to deep ocean exploration. That is to say, currently they seem like a liability, not an asset. How can we think differently to change this?&lt;/p&gt;&#xA;&lt;p&gt;Deep ocean exploration could be scientific or minerals exploration. Either field tends to be dominated by AUVs and I'm struggling to find reasons for humans to be that deep, so can someone help answer what reasons we need humans that deep? What jobs are human-specific?&lt;/p&gt;&#xA;&lt;p&gt;My first thought is that transit times are very great and surface ships are limited by weather. If there's a way to get humans closer to the site of interest then they can better maintain AUVs on site. But, this requires a substantial increase in bottom times from what currently exists. An increase by 2 to 3 orders of magnitude.&lt;/p&gt;&#xA;" OwnerUserId="22430" LastEditorUserId="22430" LastEditDate="2021-05-04T22:33:06.043" LastActivityDate="2021-05-04T22:33:06.043" Title="Deep Sea Exploration - Is there a purpose to human exploration?" Tags="|oceanography|" AnswerCount="0" CommentCount="6" ClosedDate="2021-05-10T08:27:34.963" ContentLicense="CC BY-SA 4.0" />
  <row Id="21216" PostTypeId="1" AcceptedAnswerId="21221" CreationDate="2021-05-05T13:22:24.847" Score="2" ViewCount="820" Body="&lt;p&gt;If I read around most of comments and articles on the Internet give two main reasons for the heat found in the depths of our planet :&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Super high pressure at the center of it&lt;/li&gt;&#xA;&lt;li&gt;Radioactive decay&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I need clarification on both points.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Pressure&lt;/strong&gt;: while it's pretty clear why pressure and temperature are bound in gas (*)  this becomes unclear when matter is in solid or liquid phase. &lt;strong&gt;Why pushing on a solid mass would cause its thermal agitation to raise?&lt;/strong&gt; It looks to me like most of the people takes for granted such point without proper analysis which of course involves more physics than geo-science.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Radioactivity&lt;/strong&gt;: if I put together radioactive matter it will produce heat by radioactive decay. That's fine. Nevertheless my assumption is that if I take 100kg of any matter here at Earth surface it should contain the same percentage of radioactive isotopes of 100kg of same matter taken from the center of Earth. If this is not the case, then I ask my self &lt;strong&gt;why we have higher percentage of radioactive isotopes in the center of Earth rather than in its surface?&lt;/strong&gt;&#xA;I've read somewhere that unstable isotopes are heavier and that explains why they accumulated at the center of Earth, just by gravity; but usually radioactive isotopes have just few neutrons more (or actually less!), and that make the element heavier than just 2 or 3 element next to them in the periodic table. For example Carbon-14 is lighter than Oxygen.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Can someone clarify if these two points are valid or not, and why?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;(*): even if with volume and mass constant I would say you can augment pressure by increasing temperature and not the other way round as you can't augment pressure under the constraint of having mass and volume constant&lt;/p&gt;&#xA;" OwnerUserId="22436" LastActivityDate="2021-05-07T08:21:27.183" Title="Source of heat in the center of Earth" Tags="|geothermal-heat|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21218" PostTypeId="2" ParentId="21216" CreationDate="2021-05-05T16:59:59.433" Score="1" Body="&lt;p&gt;&amp;quot;Why pushing on a solid mass would cause its thermal agitation to raise?&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;It doesn't.:&#xA;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/19588/earths-interior-heat-ratio-between-pressure-and-atomic-decay/19589#19589&quot;&gt;Earth&amp;#39;s interior heat ratio between pressure and atomic decay&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;why we have higher percentage of radioactive isotopes in the center of Earth rather than in its surface?&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;We don't know how exactly radioactive isotopes are distributed in the earth. Radiogenic heat in the core may be &lt;a href=&quot;https://ui.adsabs.harvard.edu/abs/2003AGUFM.T31G..01H/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;insignificant&lt;/a&gt;, also because the elements responsible for radiogenic heat are found rather in the Earth's bulk (mantle and eve more so crust) than in the core (&lt;a href=&quot;https://en.wikipedia.org/wiki/Goldschmidt_classification#Lithophile_elements&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lithophile elements&lt;/a&gt;). The core is mainly kept hot by primordial heat, sotosay left over heat from the release of gravitational energy during accretion and differentiation, tidal heating may also have a small part in it. &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2623/what-is-the-total-earths-interior-energy-budget/2646#2646&quot;&gt;What is the total Earth&amp;#39;s interior energy budget?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Mantle and crust store the most of earth's heat and host most of the radioactive isotopes that generate heat, specifically the crust. There's also this reasonable looking &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_internal_heat_budget&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia article&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user22279" LastEditorDisplayName="user22279" LastEditDate="2021-05-05T21:35:14.773" LastActivityDate="2021-05-05T21:35:14.773" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="21219" PostTypeId="1" CreationDate="2021-05-05T20:47:15.230" Score="1" ViewCount="48" Body="&lt;p&gt;A Deep Sea Vehicle (DSV) like Trieste or Limiting Factor or now Fundouzhe have control thrusters, ballast that has to be dumped, and other equipment to operate the DSVs.&lt;/p&gt;&#xA;&lt;p&gt;But the pressure hull is a solid sphere minus the porthole windows and a hatch?&lt;/p&gt;&#xA;&lt;p&gt;How does the pilot control these systems? Is there some conduits cut through the pressure hull? Optical penetrators could be used but how does this not compromise the integrity of the pressure hull? How else might it be done?&lt;/p&gt;&#xA;" OwnerUserId="22430" LastActivityDate="2021-05-05T20:47:15.230" Title="How do pilots of Deep Sea Vehicles operate the control surfaces and thrusters from inside a pressure hull?" Tags="|oceanography|" AnswerCount="0" CommentCount="5" ClosedDate="2021-05-07T21:19:48.950" ContentLicense="CC BY-SA 4.0" />
  <row Id="21220" PostTypeId="1" CreationDate="2021-05-05T22:36:18.817" Score="4" ViewCount="139" Body="&lt;p&gt;Co-Mn-Ni goes into some of the most efficient Lithium Ion battery chemistry. It is very convenient that Co-Mn-Ni is also readily available from the ocean seabed.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Polymetallic nodule contains various metals like copper, nickel, cobalt,&#xA;manganese, iron, lead, zinc, aluminum, etc. Of these, copper, nickel and&#xA;cobalt are of much importance and in great demand world over. In fact,&#xA;due to their extensive technological use these three metals are fast&#xA;depleting from the earth surface. Hence a world-wide research is&#xA;progressing on sea nodules as an alternative future source of these&#xA;metals&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://core.ac.uk/download/pdf/297714746.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://core.ac.uk/download/pdf/297714746.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So long as Lithium-ion remains a core battery technology, it seems that polymetallic mining from the seafloor is inevitable. Are there other sources of these elements that can be used other than the seafloor? Can recycling offset this issue?&lt;/p&gt;&#xA;" OwnerUserId="22430" LastActivityDate="2021-05-07T10:15:03.220" Title="Will Lithium batteries mean we have to exploit Co-Mn-Ni nodules from the seafloor?" Tags="|oceanography|mining|" AnswerCount="2" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="21221" PostTypeId="2" ParentId="21216" CreationDate="2021-05-06T05:09:08.150" Score="3" Body="&lt;p&gt;Geophysicists and geochemists agree on some issues, but agree to disagree on others.&lt;/p&gt;&#xA;&lt;p&gt;Where they agree is that much of the thermal energy in the Earth's core is primordial. A huge amount of heat resulting from the collisions of the myriad objects that collectively formed the Earth. Yet more heat resulted when the early Earth differentiated into an iron-heavy core and a silicon-heavy mantle and crust. The formation of a solid inner core is yet another source of heat upon which geophysicists and geochemists agree.&lt;/p&gt;&#xA;&lt;p&gt;Where they agree to disagree is that geophysicists want a large heat flux across the core-mantle boundary so as to explain the existence of the Earth's magnetic field (and to differentiate the Earth from Venus and Mars, which don't have a persistent dipole magnetic field). There is no viable source for such a large heat flux in the eyes of geochemists. Radioactive decay has been conjectured as a source of this heat.&lt;/p&gt;&#xA;&lt;p&gt;The problem with this conjecture is that the four long-lived isotopes appear to be chemically incompatible with sinking into the core. It's the other way around. They rise to the surface. Those four isotopes are isotopes of three elements, uranium, thorium, and potassium, each of which is chemically active and each of which is an &lt;a href=&quot;https://en.wikipedia.org/wiki/Incompatible_element&quot; rel=&quot;nofollow noreferrer&quot;&gt;incompatible element&lt;/a&gt;. This makes these elements more concentrated in the Earth's crust than in the mantle, and more concentrated in the mantle than in the core. The one exception might be potassium. Some studies show that potassium might change from a lithophile (&amp;quot;rock loving&amp;quot;) incompatible element to a sidereophile (&amp;quot;iron loving&amp;quot;) element at high temperature and pressure. Other studies don't show this. So once again, we're at the agree to disagree stage.&lt;/p&gt;&#xA;&lt;p&gt;The agree to disagree stage is what makes science &amp;quot;science&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2021-05-06T05:09:08.150" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21222" PostTypeId="1" AcceptedAnswerId="21225" CreationDate="2021-05-06T09:00:05.293" Score="6" ViewCount="3331" Body="&lt;p&gt;&lt;strong&gt;NOTE&lt;/strong&gt;: I first posted this question to the GIS StackOverflow site, but someone there said my question would be better suited to the Geography or Earth Science site. GIS seems the perfect place for the question to me, but in case that is correct I'm posting it here.&lt;/p&gt;&#xA;&lt;p&gt;I had asked a question (which has been answered) &lt;a href=&quot;https://gis.stackexchange.com/questions/395569/calculating-coordinates-for-halfway-around-world-from-given-location&quot;&gt;here&lt;/a&gt; about finding locations halfway around the world from a given location, in the example provided from Monterey, California.&lt;/p&gt;&#xA;&lt;p&gt;The east/west location (same latitude) is Birjand, Iran. This makes sense to me.&lt;/p&gt;&#xA;&lt;p&gt;But the north/south location is at a location north of the south pole which, even though it is a calculation I came up with and was verified there as being correct, doesn't make sense to me.&lt;/p&gt;&#xA;&lt;p&gt;The reason why my brain is having a meltdown is because it seems plain to me that the north pole to the south pole would be halfway around the world, whereas Monterey is well south of the north pole, and the location &amp;quot;agreed upon&amp;quot; as the halfway around the world point from there (from a north/south, same longitude standpoint) is in the South Pacific between New Zealand and the southern tip of South America, which is north of the South pole.&lt;/p&gt;&#xA;&lt;p&gt;It seems to me that the halfway point should be as far &amp;quot;down&amp;quot; from the south pole as Monterey is from the north pole.&lt;/p&gt;&#xA;&lt;p&gt;Am I wrong? If so, what is faulty with my logic?&lt;/p&gt;&#xA;&lt;p&gt;If I'm right, what is the halfway point, then, from Monterey?&lt;/p&gt;&#xA;&lt;h2&gt;UPDATE&lt;/h2&gt;&#xA;&lt;p&gt;I am obviously not a geographer/cartographer, but this is getting to confusinate/fascifuse me more all the time. Based on Earthworm's answer, the exit point after &amp;quot;drilling through the earth&amp;quot; from Monterey is in the Pacific Ocean as shown with pushpin #2 here (same longitude as Monterey, with the reverse latitude):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oOz5k.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oOz5k.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;However (there's almost always a &amp;quot;however&amp;quot;), based on Andy M's answer and the link he provided, these are the two points (#2 having both a different latitude AND a different longitude than Monterey, but the same longitude as Birjand, Iran):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yExJa.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yExJa.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The first antipodal point (Pacific Ocean) seems slightly more logical to me than the second one (Indian Ocean), but both differ from what my ungeometric brain was expecting before I delved into this, which was a point &amp;quot;south&amp;quot; (actually &amp;quot;negative north,&amp;quot; I guess*) of the South Pole, &amp;quot;beyond&amp;quot; Antarctica (if ya know whaddi mean).&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;As it is impossible to go &amp;quot;south&amp;quot; of the South Pole.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;h2&gt;UPDATE 2&lt;/h2&gt;&#xA;&lt;p&gt;I posted a substack article tangentially/partially about this &lt;a href=&quot;https://ramblingnotesofageezer.substack.com/p/how-to-use-map-o-matic-5-in-a-series&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="3166" LastEditorDisplayName="user20559" LastEditDate="2021-05-10T11:21:03.583" LastActivityDate="2021-05-10T11:21:03.583" Title="How can a starting point south of the north pole to an endpoint north of the south pole be halfway around the world?" Tags="|cartography|coordinate-system|" AnswerCount="6" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="21223" PostTypeId="2" ParentId="21222" CreationDate="2021-05-06T11:08:00.697" Score="12" Body="&lt;p&gt;It seems to me as if you are looking for the &lt;a href=&quot;https://en.wikipedia.org/wiki/Antipodes&quot; rel=&quot;noreferrer&quot;&gt;antipode&lt;/a&gt; of a point on earth's surface. Let's use our fingers (real life is a bit more complicated because Earth is not a sphere and different coordinate systems exist).&lt;/p&gt;&#xA;&lt;p&gt;You already have the antipode's longitude, which is your current longitude plus or minus 180°, clamped to plus/minus (or East/West) 180°, the one that lands you in Iran. From that antipodal longitude, just mirror on the equator (not a pole) Monterey's northern latitude to the southern hemisphere, so that 36°N become 36°S.&lt;/p&gt;&#xA;&lt;p&gt;That is equivalent to poking &lt;em&gt;straight through the earth's center&lt;/em&gt;, entering in Monterey and coming out on the other side.&lt;/p&gt;&#xA;&lt;p&gt;Goes without proof that the pole distances, the distances from Monterey to the north pole and from its antipode to the south pole, are the same in both cases, trivially calculated by subtracting latitude from 90°.&lt;/p&gt;&#xA;" OwnerDisplayName="user22279" LastEditorUserId="18888" LastEditDate="2021-05-07T20:44:29.423" LastActivityDate="2021-05-07T20:44:29.423" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21224" PostTypeId="2" ParentId="21222" CreationDate="2021-05-06T13:20:21.097" Score="5" Body="&lt;p&gt;There is a site that will show you the antipode for any location, and takes you through the calculation if you need it - &lt;a href=&quot;https://www.geodatos.net/en/antipodes/united-states/monterey&quot; rel=&quot;noreferrer&quot;&gt;https://www.geodatos.net/en/antipodes/united-states/monterey&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Looking at the question, and your own potential answer, that you originally posted on the GIS SE, you correctly calculated the longitude of the antipode, but you mistakenly calculated the latitude by subtracting your original latitude from 90 (the pole), when it should have been from 0 (the equator). This gave you a point further south than it should have been.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2021-05-06T13:20:21.097" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21225" PostTypeId="2" ParentId="21222" CreationDate="2021-05-06T19:27:09.130" Score="19" Body="&lt;p&gt;I think you are too into the numbers.   When talking about longitude and latitude they are two different things.  Longitude goes east and west from a point on the earth from 0 to 180 degrees east and 0 to 180 degrees west and describe semicircles of equal length running from the north pole to the south pole.  Latitude however is in degrees north or south of the equator and describe circular lines around the earth that get smaller as you get closer to the poles.  See this image:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/74ECJ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/74ECJ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Slicing along the lines of longitude would give you wedge shapes like when you think of orange slices.  Slicing along lines of latitude would give you circular slices of varying sizes.&lt;/p&gt;&#xA;&lt;p&gt;To get an 'opposite' longitude you spin the earth on it's axis 180 degrees.  The opposite of 1 degree east is 179 degrees west.  The opposite of 10 degrees east is 170 degrees west.  So in your example it will be from 121.895 degrees west (longitude -121.895) to 58.105 degrees east (longitude 58.105).&lt;/p&gt;&#xA;&lt;p&gt;The opposite latitude is also 180 degrees away.  However there are only 180 total degrees of latitude because their shapes are different.  Longitude goes from 0 to 180 degrees east and 0 to 180 degrees west giving a total of 360 degrees.  Since latitude represents a circle, there are only 180 degrees, from 0 to 90 degrees north and from 0 to 90 degrees south.  But you need to go a full 180 degrees.  The way it works is that it is just the same degrees,  just flip north and south.  Think about two points on opposite sides of the planet on the equator.  They are both at 0 degrees latitude.  If you move north 1 degree, the opposite will now be one degree south.  If you continue to 90 degrees north, the opposite is now 90 degrees south, which makes sense since the north and south pole are opposite.&lt;/p&gt;&#xA;&lt;p&gt;So let's take Monterey, CA at 36.6 (positive is north), -121.895 (negative is west).  You cannot get to the opposite side of the earth by walking along a line of latitude because all lines of latitude except for the equator are not the right size.  If you divided the earth at that line of latitude you would not get two equal halves.  You can however get to the opposite side of the earth by walking along lines of longitude.  So say you start walking north.  After 53.4 degrees of latitude you arrive at the north pole.  Keep going in a straight line and you will start walking south on longitude 58.105 (positive is east).  After you reach the equator you will have travelled 143.4 degrees.  You have 36.6 degrees of walking south to go before you end up at -36.6 degrees latitude (negative is south).  You've travelled 180 degrees in a straight line to get to the opposite side of the earth and now you're in the Indian Ocean.&lt;/p&gt;&#xA;" OwnerUserId="13537" LastEditorUserId="13537" LastEditDate="2021-05-09T06:25:32.880" LastActivityDate="2021-05-09T06:25:32.880" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21226" PostTypeId="2" ParentId="21222" CreationDate="2021-05-06T22:05:01.497" Score="3" Body="&lt;p&gt;It all depends on exactly what you mean by &amp;quot;halfway around the earth heading due north or south.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;One theoretical interpretation of that phrase is that, starting in Monterey, California, you start heading south, and you continue walking south until the distance that you've walked south is half the circumference of the earth. (Throughout this answer, I'm going to assume that the earth is a perfect sphere.)&lt;/p&gt;&#xA;&lt;p&gt;You are perfectly correct in thinking that theoretically, if you were to do that, then you would end up at some point south of the south pole.&lt;/p&gt;&#xA;&lt;p&gt;Obviously, however, you &lt;em&gt;can't&lt;/em&gt; go south of the south pole. Once you reach the south pole, it's impossible to continue walking south, because every direction is north.&lt;/p&gt;&#xA;&lt;p&gt;So with that interpretation, it's simply impossible to find a point which is &amp;quot;halfway around the earth heading due north or south.&amp;quot; (There are only two exceptions to this: the south pole is halfway around the earth heading south from the north pole, and likewise, the north pole is halfway around the earth heading north from the south pole.)&lt;/p&gt;&#xA;&lt;p&gt;However, there is another interpretation of the phrase that makes a lot more sense. We can instead interpret the phrase as meaning that, starting in Monterey, California, you start heading south, and then you continue walking &lt;em&gt;along a great circle of the earth&lt;/em&gt; until the distance that you've walked is half the circumference of the earth. If you do this, then you will walk south until you reach the south pole, and then after you pass the south pole, you will be walking north instead.&lt;/p&gt;&#xA;&lt;p&gt;If you do that, then you will end up at the antipode of Monterey, which is that point that you identified in the Indian Ocean southeast of Madagascar.&lt;/p&gt;&#xA;&lt;p&gt;It sounds like you've misunderstood &lt;a href=&quot;https://earthscience.stackexchange.com/a/21223/8120&quot;&gt;Earthworm's answer&lt;/a&gt; as stating that the halfway point is in the Pacific Ocean west of Chile. Actually, that answer gives the point in the Indian Ocean near Madagascar as the &amp;quot;halfway point.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;It wouldn't make any sense to me to designate the point in the Pacific Ocean west of Chile as the &amp;quot;halfway point.&amp;quot; After all, the distance from Monterey to that point is much, much less than half the circumference of the earth.&lt;/p&gt;&#xA;" OwnerUserId="8120" LastActivityDate="2021-05-06T22:05:01.497" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21228" PostTypeId="2" ParentId="21220" CreationDate="2021-05-07T04:50:38.633" Score="4" Body="&lt;p&gt;No it is not inevitable that the production and continued used of lithium batteries will mean the exploitation of cobalt, manganese and nickel nodules from the sea floor.&lt;/p&gt;&#xA;&lt;p&gt;Sufficient quantities of these metals are obtained from conventional land based mines.&lt;/p&gt;&#xA;&lt;h2&gt;Nickel&lt;/h2&gt;&#xA;&lt;p&gt;Two types of nickel mineralization are currently mined: sulphides and oxides (laterites).&lt;/p&gt;&#xA;&lt;p&gt;Sulphide nickel is easier to treat metallurgically than oxide nickels. Once mined nickel sulphides are initially processed using flotation plants. Nickel oxides usually need to be treated in autoclaves (high pressure cookers for minerals) and depending on secondary mineralization the autoclaves use either acid or ammonia.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.worldatlas.com/articles/top-nickel-producing-countries.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;top ten nickel producing countries&lt;/a&gt; are:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ipDkc.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ipDkc.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The major laterite producers are: Indonesia, Philippines, New Caledonia, Brazil and Cuba.&lt;/p&gt;&#xA;&lt;p&gt;The major sulphide producers are: Canada, Australia &amp;amp; Russia.&lt;/p&gt;&#xA;&lt;p&gt;Australia &lt;em&gt;also&lt;/em&gt; has significant reserves of nickel laterites (oxides).&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.mining.com/top-nickel-miners-ranked-2017-production/&quot; rel=&quot;nofollow noreferrer&quot;&gt;top nickel mining companies&lt;/a&gt; are:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EmrdR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EmrdR.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;There is plenty of land based nickel available before sea bed nodules need to be mined for nickel.&lt;/p&gt;&#xA;&lt;h2&gt;Manganese&lt;/h2&gt;&#xA;&lt;p&gt;Manganese is the &lt;a href=&quot;https://www.nsenergybusiness.com/features/manganese-producing-countries/&quot; rel=&quot;nofollow noreferrer&quot;&gt;12th most abundant element in the Earth’s crust&lt;/a&gt;. About 18.5 million tonnes of manganese are produced globally annually, from&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;South Africa   6.2 Mt&#xA;Australia      3.0 Mt&#xA;China          2.9 Mt&#xA;Gabon          1.8 Mt&#xA;Brazil         1.0 Mt&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;There are significant known resources of land based manganese for many years to come.&lt;/p&gt;&#xA;&lt;h2&gt;Cobalt&lt;/h2&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nsenergybusiness.com/features/top-cobalt-producing-countries/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cobalt&lt;/a&gt; is currently mined by eight countries, with the Congo being the main producer:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;Congo           100.0 kt&#xA;Russia            6.1 kt&#xA;Australia         5.1 kt&#xA;Philippines       4.6 kt&#xA;Cuba              3.5 kt&#xA;Madagascar        3.3 kt&#xA;Papua New Guinea  3.1 kt&#xA;Canada            3.0 kt&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Again, there is sufficient production and resources of land based Cobalt to not require the exploitation of sea bed nodules.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-05-07T10:15:03.220" LastActivityDate="2021-05-07T10:15:03.220" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21229" PostTypeId="2" ParentId="21220" CreationDate="2021-05-07T08:12:15.193" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Co-Mn-Ni goes into some of the most efficient Lithium Ion battery chemistry&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is correct.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;It is very convenient that Co-Mn-Ni is also readily available from the ocean seabed.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is less correct. Convenient from who? With resource extraction, there's no &amp;quot;convenient&amp;quot;. There's economic, or not economic.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;it seems that polymetallic mining from the seafloor is inevitable&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is incorrect.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Are there other sources of these elements that can be used other than the seafloor?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You're saying this as if we are currently mining seafloor deposits and nothing else.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;The other answer provides a comprehensive list of the current production of Ni, Co, and Mn. In short: There's plenty more Ni, Co, and Mn around and there is absolutely no shortage of us running out of that in the coming hundreds of years. On land. Not in the ocean. &lt;a href=&quot;http://elementsmagazine.org/past-issues/deep-ocean-mineral-deposits/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://elementsmagazine.org/past-issues/deep-ocean-mineral-deposits/&lt;/a&gt; Most of the stuff is paywalled, but finding the texts online isn't too hard.&lt;/p&gt;&#xA;&lt;p&gt;Specifically regarding seafloor mineral deposits, Elements Magazine published an issue two years ago outlining some of the prospects, issues, challenges, and promises in the field of seafloor mining.&lt;/p&gt;&#xA;&lt;p&gt;One of the greatest problems is the enormous environmental impact. If you're mining on land, the environmental impact is pretty much localised to where you are mining. Once you're in the oceans, you're disturbing many kilometre-squares of area. With environmentally conscious consumers and companies, there will be no market. Volvo, &lt;a href=&quot;https://www.volvogroup.com/en/sustainability/environmental-resources-efficiency.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;for example,&lt;/a&gt; are pledging for ethical sourcing of their metals. They will not buy anything produced from the seafloor. Others have followed, or will follow soon. In that case, if there's no market, there's no need for production.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-05-07T08:12:15.193" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21230" PostTypeId="2" ParentId="21216" CreationDate="2021-05-07T08:21:27.183" Score="4" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;depths of our planet&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;How deep? &amp;quot;Deep&amp;quot; is a relative thing. You can have 10 kilometres deep, or 5000 kilometres deep.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Super high pressure at the center of it&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It's not the pressure per se that's causing the heat, it was the process of getting to the pressure when the Earth's formed. Compression creates heat. That's easy to know - just touch a bicycle air pump after filling up. There's also the issue of gravitational potential energy converting into heat once Earth was accreted. The the pressure and heat are together the result of Earth's formation. It's not that pressure itself makes the heat.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Radioactive decay&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;According to what we know, the three modern heat producing elements (thorium, uranium and potassium) are actually concentrated in the mantle, with an even greater concentration in the crust, which is just the top few kilometres. It's still deep for us humans, but extremely shallow when compared to the core. There is still some debate on this (see the two other answers), but my own personal opinion is that it's safe to say there's very little U Th and K in the core.&lt;/p&gt;&#xA;&lt;p&gt;Also read my very relevant answer on the World Building website:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://worldbuilding.stackexchange.com/a/123951/39999&quot;&gt;https://worldbuilding.stackexchange.com/a/123951/39999&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-05-07T08:21:27.183" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="21231" PostTypeId="2" ParentId="18918" CreationDate="2021-05-07T13:09:49.487" Score="0" Body="&lt;p&gt;Taking water out of the sea does require energy to lift it even if it's destination will eventually be below sea level. The dam idea of retaining rain water would require energy and resources for the production of the dam and require the loss of usable land. That is not the best dam way to approach this solution.&lt;/p&gt;&#xA;&lt;p&gt;Removing water up stream, from say the Mississippi or Rio Grande, could be diverted to a lower elevation area via a pipeline or canal system. This too would require energy and resources to build, but the fresh water could at least be sent to areas that are currently unusable arid areas. This would result in a greening effect without the risk of contaminating water tables below. Another benifit would be the ability to increase the amount available farm land without the need of taking water from an already depleted ground water source. Also replenishment of water tables would occur, and your end goal of reducing the amount of water entering the ocean would be accomplished.&lt;/p&gt;&#xA;" OwnerUserId="22457" LastActivityDate="2021-05-07T13:09:49.487" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21232" PostTypeId="2" ParentId="21060" CreationDate="2021-05-07T19:44:59.357" Score="0" Body="&lt;p&gt;Here's an extensive list of Earth models, many of which are anisotropic. You'll probably want to focus on tomographic models rather than reference models.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://ds.iris.edu/spud/earthmodel&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://ds.iris.edu/spud/earthmodel&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11430" LastActivityDate="2021-05-07T19:44:59.357" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="21233" PostTypeId="1" CreationDate="2021-05-07T21:34:42.650" Score="1" ViewCount="47" Body="&lt;p&gt;I am interested in the development of scales to measure extreme weather.&lt;/p&gt;&#xA;&lt;p&gt;For example, the &lt;strong&gt;Enhanced Fujita Scale&lt;/strong&gt; for measuring the intensity of tornadoes, etc. How were they created? OK sure, I know someone, probably named Fujita, made a scale, but at what point and how did people just decide to go along with it?&lt;/p&gt;&#xA;" OwnerUserId="22462" LastActivityDate="2021-05-07T21:34:42.650" Title="How are weather intensity scales created?" Tags="|meteorology|severe-weather|tornado|mesoscale-meteorology|scale|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21234" PostTypeId="1" CreationDate="2021-05-08T12:15:44.473" Score="1" ViewCount="45" Body="&lt;p&gt;I have 2 data. A container data, 3 containers(A1,A2 and A3) all are the same height, but each have varying water volume, the table consist of change of water volume (hourly) for the weeks 1 and 2.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3DxB4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3DxB4.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;.. ..&#xA;Precipitation and rainfall intensity data (mm/hr), the range is weeks 3 and 4.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BLrmu.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BLrmu.png&quot; alt=&quot;Precipitation Data&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;..&#xA;I want to show(predict?) what will be the change of volume in the containers for weeks 3 and 4 due to precipitation. My goal is to present it using graphs or any other method applicable.&lt;/p&gt;&#xA;" OwnerUserId="22467" LastActivityDate="2021-05-08T12:15:44.473" Title="How to calculate change in volume of a container using rainfall data" Tags="|precipitation|rainfall|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21235" PostTypeId="2" ParentId="21222" CreationDate="2021-05-08T15:17:40.963" Score="3" Body="&lt;p&gt;You can travel in north-south direction to go around the world... but you can also travel east-west.  Going around the equator halfway will see no north-south change, but still be halfway around the world... so that should make clear that two antipodal points can be much less north-south change than between the North Pole to the South Pole.  They can even manage to be the same latitude.&lt;/p&gt;&#xA;&lt;p&gt;The Pacific Ocean point on your first map image can't be the right one if you look at a globe more.  Or perhaps it can help to consider an analogy of digging into a hill to kind of reflect upon the rough idea that the Earth is 3-D\curved... if you were to dig in at Monterrey and came out at the same longitude in the Pacific, it'd be quite akin to digging into your hill towards the center... and coming out on the same side you started on.  If you're going through the center, you need to come out on the opposite side, and looking at a globe, Monterrey and your SH Pacific point aren't really doing that.  Sort of like these crude diagrams:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TlXww.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TlXww.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/2XBZpm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2XBZpm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Likewise with digging through the Earth... there's a latitudinal component (north-south) and a longitudinal component (east-west) to all surface motion, and the ≈ 13,000 mile trip to get to the other side of the Earth will be some sort of combination of the two.  The North pole to south pole trip is the extreme case where all motion is latitudinal north-south.  The equator trip is the extreme case where all motion is longitudinal east-west.  All other cases will require some of each, in the right proportions to aim the line between them through the center.  Not unlike trying to cross from one side of a flat circular wall clock to the other.  On it, you must be on the &amp;quot;opposite side&amp;quot; of the center both &amp;quot;up-down&amp;quot; and &amp;quot;left-right&amp;quot; to have passed through that center.  So is the concept on the globe.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZW6MVm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZW6MVm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2021-05-08T15:25:05.913" LastActivityDate="2021-05-08T15:25:05.913" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21236" PostTypeId="1" CreationDate="2021-05-09T05:23:46.913" Score="4" ViewCount="307" Body="&lt;p&gt;Does the Earth exhibit measurable &lt;a href=&quot;https://en.wikipedia.org/wiki/Gravity_wave&quot; rel=&quot;noreferrer&quot;&gt;gravity waves&lt;/a&gt;? Note: I'm not asking about &lt;em&gt;gravitational waves&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Some recent experiments looking at low-frequency (3&lt;span class=&quot;math-container&quot;&gt;$\times 10^{-5}$&lt;/span&gt;Hz) accelerometer data are showing some features that might be explained by this. The signal that I and others have measured shows a signal at least 10 to 15 dB above the noise floor that appears to change somewhat based on local geology as determined between measurements in Japan, Hawaii, and the continental US.&lt;/p&gt;&#xA;&lt;p&gt;Any insight into crustal gravity waves with a period of roughly 9 hours, or other phenomena that might result in reproducible signals like this in accelerometers is appreciated.&lt;/p&gt;&#xA;&lt;p&gt;Any suggestions for further analysis that might differentiate among different possible explanations is also welcome!&lt;/p&gt;&#xA;" OwnerUserId="22471" LastEditorUserId="6031" LastEditDate="2021-05-15T22:44:32.597" LastActivityDate="2023-11-11T14:28:21.543" Title="Does the Earth produces measurable gravity waves?" Tags="|seismology|data-analysis|gravity|instrumentation|" AnswerCount="2" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="21237" PostTypeId="1" CreationDate="2021-05-09T10:07:13.533" Score="1" ViewCount="333" Body="&lt;p&gt;In tectonic geomorphology the Mountain front sinuosity index is one of the morphometric indexes.&lt;/p&gt;&#xA;&lt;p&gt;Smf = Lmf/Ls&lt;/p&gt;&#xA;&lt;p&gt;I have a DEM, so how do I use it to find the value?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lrILS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lrILS.jpg&quot; alt=&quot;&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;According to this diagram do I have to digitize all the mountain front?&lt;/p&gt;&#xA;" OwnerUserId="15238" LastActivityDate="2021-05-09T10:07:13.533" Title="How to calculate mountain front sinuosity index using DEM?" Tags="|geology|geomorphology|tectonics|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21238" PostTypeId="2" ParentId="21222" CreationDate="2021-05-09T11:25:14.843" Score="2" Body="&lt;p&gt;It's easy to get confused by &lt;a href=&quot;https://en.wikipedia.org/wiki/Great-circle_distance&quot; rel=&quot;nofollow noreferrer&quot;&gt;great circle distances&lt;/a&gt; when looking at a flat map.&lt;/p&gt;&#xA;&lt;p&gt;I find it much easier to understand the concept while looking at a &lt;a href=&quot;https://en.wikipedia.org/wiki/Globe&quot; rel=&quot;nofollow noreferrer&quot;&gt;globe&lt;/a&gt;, or if I don't have any, on Google Earth.&lt;/p&gt;&#xA;&lt;p&gt;The trick is to rotate the globe and redefine the north pole, so that Monterey is on &amp;quot;top&amp;quot; of the world.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FQI1i.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FQI1i.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;With our new definition:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Monterey is now the North Pole.&lt;/li&gt;&#xA;&lt;li&gt;Every direction is &amp;quot;South&amp;quot;.&lt;/li&gt;&#xA;&lt;li&gt;Starting from Monterey, every direction is a &lt;a href=&quot;https://en.wikipedia.org/wiki/Meridian_(geography)&quot; rel=&quot;nofollow noreferrer&quot;&gt;meridian&lt;/a&gt;, and a great circle.&lt;/li&gt;&#xA;&lt;li&gt;From any direction, if you keep walking ~20000km, you'll land on the South Pole (= the &lt;a href=&quot;https://en.wikipedia.org/wiki/Antipodes&quot; rel=&quot;nofollow noreferrer&quot;&gt;antipode&lt;/a&gt; of Monterey, as mentioned by others)&lt;/li&gt;&#xA;&lt;li&gt;Every point on the Equator is ~10000km away from Monterey&lt;/li&gt;&#xA;&lt;li&gt;For any given latitude, the points on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Latitude&quot; rel=&quot;nofollow noreferrer&quot;&gt;parallel&lt;/a&gt; will all have the same distance to Monterey.&lt;/li&gt;&#xA;&lt;li&gt;If you keep walking ~40000km, in any direction, you'll land back in Monterey.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Once you found an interesting place with this technique, you can use the original latitude/longitude grid to get the correct coordinates.&lt;/p&gt;&#xA;&lt;p&gt;In comparison, the newly defined &amp;quot;equator&amp;quot; looks like a sine curve on a flat map. The green area is the &amp;quot;northern hemisphere&amp;quot;, the white line represents every point 10000km away from Monterey:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FD56T.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FD56T.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12617" LastEditorUserId="12617" LastEditDate="2021-05-09T11:51:38.220" LastActivityDate="2021-05-09T11:51:38.220" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21239" PostTypeId="1" AcceptedAnswerId="21249" CreationDate="2021-05-09T14:24:06.493" Score="-2" ViewCount="384" Body="&lt;p&gt;This question is being redirected from the &lt;a href=&quot;https://chemistry.stackexchange.com/questions/151174/how-are-we-going-to-handle-oxygen-shortage-problem-arising-due-to-massive-usage?noredirect=1#comment308086_151174&quot;&gt;Chemistry&lt;/a&gt; Stack Exchange community.&lt;/p&gt;&#xA;&lt;p&gt;The current corona pandemic has created a situation where in order to save lives, there is a huge huge requirement for clinical oxygen (which is taken from the environment) all over the world. Now, there is a great hype about (and industrial migration towards) the hydrogen fuel cell tech which can replace the current polluting fossil fuel infrastructure. Which is great and I'm personally an enthusiast of this emerging field.&lt;/p&gt;&#xA;&lt;p&gt;Traditional hydrocarbons had their chemical reaction as:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;hydrocarbon + oxygen =&amp;gt; carbon (di/mono)oxide + other harmful residual gases&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Which is certainly polluting and is causing climate change and global warming. Whereas hydrogen fuel cell overall (both fuel cell anode and cathode) reaction is:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;hydrogen + oxygen =&amp;gt; water (vapor) + electricity&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Here we become relaxed as we know that water isn't toxic to the environment and some FCEV (fuel cell electric vehicle) manufacturers claim that the water from the exhaust of their vehicles is fit for drinking.&lt;/p&gt;&#xA;&lt;p&gt;But the common factor in both of the reactions is that the environmental oxygen is entrapped in either some oxide form or water, which will need a definite amount of external energy to again be in the form of oxygen molecule.&lt;/p&gt;&#xA;&lt;p&gt;The question is, who is going to spend that energy? Hydrogen production, storage and delivery is already a very energy and capital consumptive process and even the businesses that generate hydrogen through mass scale water electrolysis will use/sell the oxygen by product to add to their overall profits.&lt;/p&gt;&#xA;&lt;p&gt;Tree Plantation/Reforestation cannot compensate for these oxygen losses alone.&lt;/p&gt;&#xA;&lt;p&gt;It seems that we are not actually solving the whole of the problem and the part which is being ignored, can itself be the next crisis.&lt;/p&gt;&#xA;" OwnerUserId="22476" OwnerDisplayName="lousycoder" LastEditorDisplayName="user20559" LastEditDate="2021-05-10T11:19:23.043" LastActivityDate="2021-05-10T18:06:42.083" Title="How are we going to handle oxygen shortage problem arising due to massive usage of current fossil fuel combustion and future Hydrogen fuel cell tech?" Tags="|atmosphere|climate-change|geochemistry|energy|" AnswerCount="2" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="21240" PostTypeId="2" ParentId="21236" CreationDate="2021-05-09T17:44:02.583" Score="2" Body="&lt;p&gt;Edit: This answer refers to the first version of this question which asked about &amp;quot;gravitational waves&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Typically, the term &amp;quot;gravitational wave&amp;quot; is reserved for distortions (&amp;quot;strain&amp;quot;) in spacetime, in accordance with General Relativity. &lt;a href=&quot;https://en.wikipedia.org/wiki/Gravitational_wave&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gravitational waves&lt;/a&gt; are a property of spacetime and can thus propagate in empty space. In contrast, what you measure here are simply &lt;a href=&quot;https://en.wikipedia.org/wiki/Seismic_wave&quot; rel=&quot;nofollow noreferrer&quot;&gt;seismic waves&lt;/a&gt;, such as pressure waves propagating through Earth and your setup. In fact, seismic waves are the limiting noise that prevents gravitational wave detectors such as aLIGO to measure at lower frequencies, see e.g. &lt;a href=&quot;https://arxiv.org/abs/1604.00439&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt; for a discussion and plots.&lt;/p&gt;&#xA;" OwnerUserId="22477" LastEditorUserId="22477" LastEditDate="2021-05-16T12:46:48.027" LastActivityDate="2021-05-16T12:46:48.027" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="21241" PostTypeId="1" AcceptedAnswerId="21242" CreationDate="2021-05-09T18:53:59.130" Score="12" ViewCount="7490" Body="&lt;p&gt;In the morning, Google shows the temperature from four or five hours ago (around 2:00 a.m.). But then I update the report, and I get the temperature slightly lower than before.&lt;/p&gt;&#xA;&lt;p&gt;Why is the temperature at 2:00 a.m. higher than the temperature at 7:00 a.m.?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorUserId="19122" LastEditDate="2021-05-09T19:33:35.153" LastActivityDate="2021-05-12T03:39:11.387" Title="Why are mornings cooler than nights?" Tags="|meteorology|atmosphere|temperature|" AnswerCount="2" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="21242" PostTypeId="2" ParentId="21241" CreationDate="2021-05-09T19:08:24.137" Score="30" Body="&lt;p&gt;The Earth is always radiating heat to the space. But in the day the Sun delivers some heat. The net heat flux is then defined as the sum of those two factors. If the energy delivered by the Sun is bigger than the cooling rate, the Earth is net warming (positive net flux – we can imagine it like heat is travelling &amp;quot;to us&amp;quot;), as opposed to the opposite case (cooling; negative net flux – heat is travelling &amp;quot;away&amp;quot;).&lt;/p&gt;&#xA;&lt;p&gt;In the day, the Sun warms the ground until the evening. The Sun's heating rate is higher than the cooling rate, so the temperature is rising until it gets to a point where the heating rate is same as cooling rate. This happens in the evening, so the temperature is steady at that point. But the Sun goes even lower, so the net flux becomes negative. In the night there is only cooling of Earth, so the temperature is falling steadily until the Sun is high enough that it balances the cooling. This happens at a point of a minimum temperature.&lt;/p&gt;&#xA;&lt;p&gt;Of course, this is valid for most of the days, but we can have some other effects that can change the time of the minimum temperature (clouds, fronts or advection, for example).&lt;/p&gt;&#xA;&lt;p&gt;On graph:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9z4HAm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9z4HAm.png&quot; alt=&quot;T(t)&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So, the temperature is falling over night after the sunset, but rises again after the sunrise. Thus, the temperature is at its lowest point in the morning.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Appendix for all you loving calculations:&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Note: Simplified to toy model, no atmosphere&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;The cooling rate of the Earth is approximatelly given by the Stefan-Boltzmann equation:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$j_E=\sigma\cdot T^4=5.670  \cdot 10^{-8} \frac{W}{m^2 K^4} \cdot (288.15 K)^4 = 390 \frac{W}{m^2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The maximum heating rate of Sun in the zenith is &lt;span class=&quot;math-container&quot;&gt;$j_{\text{S max}}=1361 \frac{W}{m^2}$&lt;/span&gt;. So, the heating rate of Sun at altitude &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt; is:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$j_S=j_{\text{S max}}\cdot \sin{\alpha}=1361 \frac{W}{m^2}\cdot \sin{\alpha}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;When is the heating rate equal to zero?&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$0=j_S-j_E=1361 \frac{W}{m^2}\cdot \sin{\alpha} - 390 \frac{W}{m^2}$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$1361 \frac{W}{m^2}\cdot \sin{\alpha} = 390 \frac{W}{m^2}$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\alpha = 17 °$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;So, with our calculations, the minimum temperature is at the time when the altitude is equal to 17°.&lt;/p&gt;&#xA;" OwnerUserId="19122" LastEditorUserId="-1" LastEditDate="2021-05-11T17:21:46.237" LastActivityDate="2021-05-11T17:21:46.237" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="21243" PostTypeId="2" ParentId="21239" CreationDate="2021-05-10T06:07:40.043" Score="3" Body="&lt;p&gt;What oxygen shortage?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth's atmosphere&lt;/a&gt; contains 20.9 percent oxygen. There's a lot of oxygen in the atmosphere and its depletion rate from burning fossil fuels has been small. Humans have been burning fossil fuels on an industrial scale for a long time: coal fired power stations, internal combustion engines in cars, trucks, train locomotives, aircraft and ships, steam engines, oil and coal fired boilers for domestic heating, coal, oil and gas as sources of heat for industrial purposes, etc.&lt;/p&gt;&#xA;&lt;p&gt;The atmosphere has a mass of about 5.15×10&lt;sup&gt;18&lt;/sup&gt; kg, which means the amount of oxygen in the atmosphere is 1.07×10&lt;sup&gt;18&lt;/sup&gt; kg.&lt;/p&gt;&#xA;&lt;p&gt;Concerning hydrogen fuel cells and other forms of usage of hydrogen as an energy source, the hydrogen that would be used would be derived from electrolysis. Water molecules are split by applying electricity to them, hence the system makes both hydrogen and oxygen gas.&lt;/p&gt;&#xA;&lt;p&gt;All the proposals I have seen for industrial scaled electrolysis derived hydrogen plants intend to use either wind power or solar power as the source of electricity. Most of the proposals intend to use sea water.&lt;/p&gt;&#xA;&lt;p&gt;When hydrogen derived from splitting water is used in a fuel cell or burned by other means as a source of energy it will consume atmospheric oxygen, but any oxygen derived from splitting water, when used for medical purposes or otherwise means that that amount of atmospheric oxygen will &lt;em&gt;&lt;strong&gt;not&lt;/strong&gt;&lt;/em&gt; be used.&lt;/p&gt;&#xA;&lt;p&gt;My concerns about the use of hydrogen as an energy source are the safety aspects and the potential rise in localized humidity, particularly in warmer parts of the world. This would have implications concerning localized temperatures and the ability of people and animals to sweat and lose body heat when they need to if there was a lot water vapor produced from a high concentration of hydrogen consuming devices.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-05-10T10:27:29.123" LastActivityDate="2021-05-10T10:27:29.123" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21244" PostTypeId="2" ParentId="21158" CreationDate="2021-05-10T06:18:36.873" Score="-1" Body="&lt;p&gt;The gulf stream is the fastest under water ocean current inthe world ,with peak velocities 2 meters per second ,the gulf stream, at the straits of Florida and cape hatteras.&lt;a href=&quot;https://i.stack.imgur.com/X1qBF.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;enter image description here&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22483" LastActivityDate="2021-05-10T06:18:36.873" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="21245" PostTypeId="1" AcceptedAnswerId="21246" CreationDate="2021-05-10T11:37:27.263" Score="1" ViewCount="1437" Body="&lt;p&gt;Objects orbit the sun because of the sun's gravity, and Earth's gravity is weaker than the sun's gravitational pull.  So why does the moon orbit the Earth instead of the sun?&lt;/p&gt;&#xA;" OwnerUserId="22483" LastEditorUserId="6298" LastEditDate="2022-10-04T00:58:00.463" LastActivityDate="2022-10-04T00:58:00.463" Title="Why does the moon orbit the earth and not the sun instead?" Tags="|gravity|" AnswerCount="2" CommentCount="0" ClosedDate="2021-05-10T16:04:42.530" ContentLicense="CC BY-SA 4.0" />
  <row Id="21246" PostTypeId="2" ParentId="21245" CreationDate="2021-05-10T11:42:36.017" Score="7" Body="&lt;p&gt;The moon does orbit the sun but it also orbits the earth.  But your assertion that the earth's gravity is weaker than the sun's is not universally true.  If the sun's gravitational pull were greater than the earth's HERE on the earth, the sun would literally suck everything not attached to the earth's surface into itself.  Clearly that's not happening.&lt;/p&gt;&#xA;&lt;p&gt;Remember that Newton's Law of Gravitation says that the force is inversely proportional to the SQUARE of the distance.  So while the sun does have a stronger gravitational pull, the distance that both we and the moon are at makes the earth's field dominate.&lt;/p&gt;&#xA;" OwnerUserId="22489" LastActivityDate="2021-05-10T11:42:36.017" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21247" PostTypeId="2" ParentId="21245" CreationDate="2021-05-10T11:43:27.467" Score="2" Body="&lt;p&gt;The sun's gravity is strong but the the earth overwhelms the sun's gravity ,and the moon is in the in the place where the earth's gravity overwhelms the sun's, so in short the moon orbit the earth because it is in the place where earth's gravity overwhelms the sun's&lt;/p&gt;&#xA;" OwnerUserId="22483" LastActivityDate="2021-05-10T11:43:27.467" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21248" PostTypeId="2" ParentId="21158" CreationDate="2021-05-10T12:52:11.793" Score="1" Body="&lt;p&gt;&lt;a href=&quot;https://www.foxnews.com/science/fastest-ocean-current-ever-flows-beneath-antarctica&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; in Fox News points to &lt;a href=&quot;https://www.nature.com/articles/ngeo842#citeas&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt; and asserts that the fastest deep current measured is the Antarctic.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Rintoul, of the Antarctic Climate and Ecosystems Cooperative Research&#xA;Center in Hobart, said it proved to be the fastest deep ocean current&#xA;yet found, with an average speed of 7.9 inches a second (0.20 m/s).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I have no access to the paper, I can only read the abstract. I guess Fox News didn't lie this time as they are sourcing a scientifical paper of Nature Geoscience.&lt;/p&gt;&#xA;&lt;p&gt;Fukamachi, Y., Rintoul, S., Church, J. et al. Strong export of Antarctic Bottom Water east of the Kerguelen plateau. Nature Geosci 3, 327–331 (2010). &lt;a href=&quot;https://doi.org/10.1038/ngeo842&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1038/ngeo842&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-05-10T13:39:48.933" LastActivityDate="2021-05-10T13:39:48.933" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21249" PostTypeId="2" ParentId="21239" CreationDate="2021-05-10T18:06:42.083" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://scrippso2.ucsd.edu&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atmospheric oxygen levels have in fact been declining.&lt;/a&gt;  Current estimates indicate that the level is decreasing at a rate of approximately 19 parts per million per year.  This would mean that it would take approximately 500 years, at current rates of consumption, for the the oxygen concentration of the atmosphere to decrease by 1% relative to its current levels.  However, &lt;a href=&quot;https://ourworldindata.org/how-long-before-we-run-out-of-fossil-fuels&quot; rel=&quot;nofollow noreferrer&quot;&gt;best estimates indicate&lt;/a&gt; that if we continue burning fossil fuels at the current rate, we will exhaust the known reserves of coal in a little over 100 years, and oil and gas before that.  So even if we kept burning fossil fuels at today's rates (which seems increasingly unlikely), we would not be able to exhaust atmospheric oxygen via the combustion of fossil fuels.&lt;/p&gt;&#xA;&lt;p&gt;As far as the combustion of hydrogen in a hydrogen economy goes:  let's do a worst-case scenario analysis.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The current world energy consumption is around &lt;span class=&quot;math-container&quot;&gt;$5.7 \times 10^{20}$&lt;/span&gt; joules per year.  Let's imagine a future where it is 10 times larger, or &lt;span class=&quot;math-container&quot;&gt;$5.7 \times 10^{21}$&lt;/span&gt; joules per year.  Let's further imagine (and here's where it gets totally unrealistic) that the world's entire energy supply goes through hydrogen.&lt;/li&gt;&#xA;&lt;li&gt;One kilogram of hydrogen releases 142 MJ of energy when burned.  This means that this hypothetical world would need about &lt;span class=&quot;math-container&quot;&gt;$4 \times 10^{13}$&lt;/span&gt; kg of hydrogen each year.  Accounting for inefficiency losses, let's bump that up by a factor of 5, to a world hydrogen production of &lt;span class=&quot;math-container&quot;&gt;$2 \times 10^{14}$&lt;/span&gt; kg per year.&lt;/li&gt;&#xA;&lt;li&gt;Each &lt;span class=&quot;math-container&quot;&gt;$\text{H}_2$&lt;/span&gt; molecule, when formed from water, would also create one oxygen atom as a byproduct.  Let's assume that the hydrogen manufacturers sequester 100% of this oxygen somehow.  Since water is 8 parts oxygen to 2 parts hydrogen by weight, this would mean that &lt;span class=&quot;math-container&quot;&gt;$1.6 \times 10^{15}$&lt;/span&gt; kg of oxygen per year would be removed from the atmosphere.&lt;/li&gt;&#xA;&lt;li&gt;The atmosphere contains (per &lt;a href=&quot;https://earthscience.stackexchange.com/a/21243/4837&quot;&gt;Fred's answer&lt;/a&gt;) about &lt;span class=&quot;math-container&quot;&gt;$10^{18}$&lt;/span&gt; kg of oxygen.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Putting these numbers together, we find that it would take about 600 years to exhaust the atmosphere's oxygen supply.  So even under this worst-case scenario, it would not be a pressing concern.&lt;/p&gt;&#xA;&lt;p&gt;But here's the other question in a scenario like this:  what on Earth would humanity do with &lt;span class=&quot;math-container&quot;&gt;$1.6 \times 10^{15}$&lt;/span&gt; kg of oxygen per year?  In 2018, &lt;a href=&quot;https://www.globenewswire.com/news-release/2019/08/22/1905632/0/en/Global-Demand-for-Industrial-Oxygen-Likely-to-Rise-at-6-CAGR-through-2029-Future-Market-Insights.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;global sales of industrial oxygen&lt;/a&gt; were about 380 million tons, or about &lt;span class=&quot;math-container&quot;&gt;$4 \times 10^{11}$&lt;/span&gt; kg.  To believe in this scenario, you would have to believe that there would somehow be a market for &lt;em&gt;four thousand times&lt;/em&gt; more industrial and medical oxygen than we currently consume.  It seems likely that long before we got to a point like this, the price of oxygen would fall substantially, to the point where at least some producers would find it more economical to vent the oxygen back into the atmosphere rather than bother with storing and selling it.  Which would push the time-frame for this to become a problem even further into the future.&lt;/p&gt;&#xA;" OwnerUserId="4837" LastActivityDate="2021-05-10T18:06:42.083" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21250" PostTypeId="1" CreationDate="2021-05-11T01:21:59.413" Score="3" ViewCount="37" Body="&lt;p&gt;What is the environmental impact of masks and other personal protective equipment polluting the oceans?  The world is using billions of masks and gloves due to the COVID pandemic and they are being found amongst the trash in beach cleanups.&lt;/p&gt;&#xA;" OwnerUserId="18509" LastEditorUserId="543" LastEditDate="2021-05-11T03:02:16.717" LastActivityDate="2021-05-11T03:02:16.717" Title="What is the environmental effect of personal protective equipment on the ocean?" Tags="|oceanography|water|pollution|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21251" PostTypeId="2" ParentId="21241" CreationDate="2021-05-11T18:40:35.260" Score="-1" Body="&lt;p&gt;Your question is a bit ill-formed. There are more precise statements that we might take you as asking, for instance you might be claiming that the low takes place after sunrise, and be asking why that is. A very basic model of the temperature is that it is a sinusoidal function of time, and it is driven by the intensity of solar energy, also modelled as a sinusoidal function of time (that is, the net power, when the heat radiating from the Earth is subtracted from the heat coming from the Sun, is modelled as a sin function). If we had that the solar power is &lt;span class=&quot;math-container&quot;&gt;$P(t) = -\cos(t)$&lt;/span&gt; where midnight is considered to be both &lt;span class=&quot;math-container&quot;&gt;$0$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$2\pi$&lt;/span&gt;, and temperature is &lt;span class=&quot;math-container&quot;&gt;$T(t)$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$T'(t) = P(t)$&lt;/span&gt;, then we would actually have &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$P$&lt;/span&gt; being &lt;span class=&quot;math-container&quot;&gt;$\pi/2$&lt;/span&gt; (that is, six hours) out of phase with each other. That is, solving for &lt;span class=&quot;math-container&quot;&gt;$T(t)$&lt;/span&gt; gives us &lt;span class=&quot;math-container&quot;&gt;$\sin$&lt;/span&gt;, and &lt;span class=&quot;math-container&quot;&gt;$\sin(t)$&lt;/span&gt; is the same as &lt;span class=&quot;math-container&quot;&gt;$P(t-\pi/2)$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The actual equation will be much more complicated: solar power isn't a sine wave, there are heat reservoir effects, radiative cooling depends on the current temperature, etc. The actual displacement between the minima will depend on all of those factors, but the general principle that the &lt;a href=&quot;https://en.wikipedia.org/wiki/Forcing_function_(differential_equations)&quot; rel=&quot;nofollow noreferrer&quot;&gt;forcing function&lt;/a&gt; and the response function tend to be out of phase holds.&lt;/p&gt;&#xA;" OwnerUserId="11501" LastEditorUserId="11501" LastEditDate="2021-05-12T03:39:11.387" LastActivityDate="2021-05-12T03:39:11.387" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21252" PostTypeId="1" CreationDate="2021-05-11T19:20:27.313" Score="4" ViewCount="205" Body="&lt;p&gt;CO&lt;sub&gt;2&lt;/sub&gt; levels fell during the last interglacial-glacial transition until the &lt;a href=&quot;https://en.wikipedia.org/wiki/Last_Glacial_Maximum&quot; rel=&quot;nofollow noreferrer&quot;&gt;Last Glacial Maximum&lt;/a&gt; in the &lt;a href=&quot;https://www.britannica.com/science/Pleistocene-Epoch&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pleistocene&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sNu2g.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sNu2g.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I can think of two causes for the reduction of CO&lt;sub&gt;2&lt;/sub&gt;:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Ocean absorption&lt;/strong&gt;. The temperature dropped and the ocean began to absorb more CO&lt;sub&gt;2&lt;/sub&gt;, according to &lt;a href=&quot;https://en.wikipedia.org/wiki/Henry%27s_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Henry's law&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Biosphere absorption&lt;/strong&gt;. For example, fixed nitrogen is a limiting nutrient for algae in the low-latitude ocean, and its oceanic inventory may have been higher during the ice ages, thus helping to lower atmospheric CO&lt;sub&gt;2&lt;/sub&gt; during those intervals (Ren et al.,2009).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;What was the relative role (quantitatively) that both process played in the CO&lt;sub&gt;2&lt;/sub&gt; fall?&lt;/p&gt;&#xA;&lt;p&gt;Was the ocean the main CO&lt;sub&gt;2&lt;/sub&gt; sink and the biosphere absorption secondary? Or conversely both played a similar role (or even biosphere was a larger sink)?&lt;/p&gt;&#xA;&lt;p&gt;Are there other sinks than biosphere and oceans?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;H. Ren, D. M. Sigman1, A. N. Meckler, B. Plessen, R. S. Robinson, Y. Rosenthal, G. H. Haug (2009)&lt;/strong&gt;: &amp;quot;Foraminiferal isotope evidence of reduced nitrogen fixation in the ice age Atlantic Ocean&amp;quot; &lt;em&gt;Science&lt;/em&gt; 09 Jan 2009: Vol. 323, Issue 5911, pp. 244-248&#xA;DOI: 10.1126/science.1165787&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-10-15T10:52:15.920" LastActivityDate="2021-10-19T05:15:35.757" Title="Atmospheric $\ce{CO2}$ fell at a Pleistocene interglacial-glacial transition. Ocean absorption vs biosphere absorption" Tags="|oceanography|carbon-cycle|biogeochemistry|glaciation|biomass|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="21253" PostTypeId="1" CreationDate="2021-05-11T20:02:49.653" Score="2" ViewCount="493" Body="&lt;p&gt;I am working on WRF_Chem, I would like to calculate the concentration of CO2 just in the Planetary boundary layer(I mean, I want to calculate CO2 from surface to top of PBL).in WRF How can I calculate the level of PBL.&#xA;in WRF we have (PBLH: the height of PBL but it doesn't inform us what is the top level of PBL compare all level of the model?).&#xA;my model has a 37vertical levels.&#xA;If I Know the level of PBL, I will calculate the pressure weight of its level and calculate the contribution of PBL concentration.&#xA;how can I find the concentration Of CO2 in PBL height considering the weight of PBL layer?&#xA;thank you for all your guidance.&lt;/p&gt;&#xA;" OwnerUserId="18881" LastEditorUserId="543" LastEditDate="2021-05-12T04:52:45.960" LastActivityDate="2021-06-11T05:03:45.307" Title="How to find the top level of the planetary boundary layer in WRF?" Tags="|meteorology|weather-forecasting|wind|wrf|wrf-chem|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21254" PostTypeId="2" ParentId="21253" CreationDate="2021-05-11T20:28:38.090" Score="2" Body="&lt;p&gt;Well, the variable &lt;code&gt;PBLH&lt;/code&gt; should tell you the PBL height. If you want the level that the PBL is, I suggest modifying the &lt;a href=&quot;https://github.com/wrf-model/WRF/blob/master/Registry/Registry.EM_COMMON&quot; rel=&quot;nofollow noreferrer&quot;&gt;Registry.EM_COMMON&lt;/a&gt; file.&lt;/p&gt;&#xA;&lt;p&gt;Perhaps I can refer you to &lt;a href=&quot;https://wrf-python.readthedocs.io/en/latest/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;WRF-Python&lt;/a&gt; to help you with your calculation. For example, &lt;a href=&quot;https://wrf-python.readthedocs.io/en/latest/user_api/generated/wrf.interplevel.html#wrf.interplevel&quot; rel=&quot;nofollow noreferrer&quot;&gt;wrf.interplevel&lt;/a&gt; might be the function to use to interpolate to the PBL height. If you interpolate to fractions of the PBL height, &lt;a href=&quot;https://docs.scipy.org/doc/scipy/reference/integrate.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;you could one of the integration methods&lt;/a&gt; to sum up the number of fractions of the PBL height and get the average concentration of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; in the PBL (also, divide by the PBL height to actually get the average).&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-05-11T20:28:38.090" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21255" PostTypeId="1" AcceptedAnswerId="21257" CreationDate="2021-05-11T23:38:24.170" Score="4" ViewCount="192" Body="&lt;p&gt;While watching the Starlink 25 launch earlier this month, I noticed that the Florida peninsula seemed to be nicely outlined by clouds.  Pulling up satellite imagery from that time showed that my impression was correct: virtually the entire southeastern United States was covered with small, puffy clouds, neatly cut off at the coastline, with clear skies over the ocean.&lt;/p&gt;&#xA;&lt;p&gt;What causes this?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/j23pV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/j23pV.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2643" LastActivityDate="2021-05-12T08:36:19.987" Title="Why are clouds outlining the southeastern United States?" Tags="|meteorology|clouds|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21256" PostTypeId="1" CreationDate="2021-05-11T23:51:28.107" Score="3" ViewCount="68" Body="&lt;p&gt;As far as I am aware, there are two separate processes that cause Eastern Boundary Currents (EBCs) to have cold Sea Surface Temperatures (SSTs). One is offshore Ekman transport, which leads to coastal upwelling of cold subsurface waters. The other is simply equatorward advection of cold polar waters. But have there been quantitative studies of which process is dominant?&lt;/p&gt;&#xA;" OwnerUserId="11328" LastActivityDate="2021-05-11T23:51:28.107" Title="What makes Eastern Boundary Currents cold?" Tags="|atmosphere|oceanography|ocean-currents|coastal|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21257" PostTypeId="2" ParentId="21255" CreationDate="2021-05-12T08:36:19.987" Score="9" Body="&lt;p&gt;The small puffy clouds over Florida are cumulus clouds ('fair weather clouds' accompanying the launch). The sun heats the ground and the ground composition is not evenly distributed, where air is warmed more quickly it starts to rise until the moisture it contains condensates, forming clouds, while colder air in between sinks. This is called convection, in this case limited to the lower atmosphere over Florida.&lt;/p&gt;&#xA;&lt;p&gt;The ocean is mostly free of them because it isn't heated as much as the land and warming is more uniformly distributed, so that in that specific weather situation (high pressure it seems) no convection did develop over water.&lt;/p&gt;&#xA;" OwnerDisplayName="user22279" LastActivityDate="2021-05-12T08:36:19.987" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21258" PostTypeId="1" CreationDate="2021-05-13T19:10:32.487" Score="5" ViewCount="226" Body="&lt;p&gt;I'm interested in the limiting factors on the height of mountains. There is a very good explanation at &lt;a href=&quot;https://www.quora.com/How-tall-can-a-mountain-become-on-Earth-Neil-deGrasse-Tyson-says-Mount-Everest-is-about-as-tall-as-a-mountain-on-Earth-can-grow-%E2%80%9D-but-Mauna-Kea-is-significantly-taller-about-15-than-Everest&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.quora.com/How-tall-can-a-mountain-become-on-Earth-Neil-deGrasse-Tyson-says-Mount-Everest-is-about-as-tall-as-a-mountain-on-Earth-can-grow-%E2%80%9D-but-Mauna-Kea-is-significantly-taller-about-15-than-Everest&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The actual lithospheric limit to mountain height averages about half the height of Everest, which is why Fourteeners are so famous in Colorado. Mountains that exceed this limit have local geologic circumstances that make their height possible, e.g. stronger or denser rocks. In the case of Everest and the Himalayas, you have a geologic situation that is very rare in Earth history. The Indian plate is ramming into the Eurasian plate with such force that instead of just wrinkling the crust on either side into mountain ranges it has actually succeeded in lifting the Eurasian plate up on top. So the Himalayas have double the thickness of the average continental plate, thus double the mountain height that would be considered &amp;quot;normal&amp;quot;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;That seems to make perfect sense, providing a logical explanation for why the Himalayas and Rockies are both the height they are.&lt;/p&gt;&#xA;&lt;p&gt;But what about the Andes? Chimborazo 6268 m, Cotopaxi 5897 m, Aconcagua 6962 m, all considerably higher than the 14,000 feet (4270 m) suggested to be the normal limit. And this is not a case of two continental plates colliding. It's a continental plate and an oceanic plate, so the explanation that applies to the Himalayas cannot apply here.&lt;/p&gt;&#xA;&lt;p&gt;How do the Andes manage to be as tall as they are?&lt;/p&gt;&#xA;" OwnerUserId="7911" LastEditorDisplayName="user20559" LastEditDate="2021-05-14T11:46:01.063" LastActivityDate="2021-05-14T11:46:01.063" Title="How do the Andes get so high?" Tags="|geology|geophysics|plate-tectonics|mountains|mountain-building|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="21259" PostTypeId="1" CreationDate="2021-05-14T17:26:06.023" Score="3" ViewCount="144" Body="&lt;p&gt;The question came to me when pondering the Andes:&lt;/p&gt;&#xA;&lt;p&gt;Is a slab-breakoff always connected to the transition from subduction of oceanic crust to a continent/continent collision?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RKoYS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RKoYS.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Current understanding is that subduction, or quite general plate tectonics, is mainly driven &lt;a href=&quot;https://www.eurekalert.org/pub_releases/2019-09/scp-wdp090219.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;by the pull caused by the negative buoyancy of cold, dense oceanic crust&lt;/a&gt;, with other factors playing a minor role.&lt;/p&gt;&#xA;&lt;p&gt;Let's look at the destructive end: When the oceanic crust subducts under a continent it vanishes into the mantle, possibly dragging a less denser continental mass after it, until the ocean has closed and that dragged continent collides with the other one. We know that happened in the Himalayas, the European Alps and with the Appalachians (list not complete).&lt;/p&gt;&#xA;&lt;p&gt;It has been theorized that under the unwillingness of continental crust to subduct in a continent/continent collision, the pull forces can cause the dangling oceanic crust to &lt;a href=&quot;https://en.wikipedia.org/wiki/Slab_detachment&quot; rel=&quot;nofollow noreferrer&quot;&gt;detach&lt;/a&gt;. Such detached slabs of long since subducted ocean floor may still reside in the mantle, e.g. under the &lt;a href=&quot;https://pubs.geoscienceworld.org/gsa/geology/article-abstract/44/4/283/132040/Eocene-Neo-Tethyan-slab-breakoff-constrained-by-45&quot; rel=&quot;nofollow noreferrer&quot;&gt;Himalayas&lt;/a&gt;, in several stages in the &lt;a href=&quot;https://www.nature.com/articles/srep31010&quot; rel=&quot;nofollow noreferrer&quot;&gt;Alps&lt;/a&gt;, where the 'sudden' gain in buoyancy caused by the detachment may be one of the drivers for the uplift and orogeny.&lt;/p&gt;&#xA;&lt;p&gt;Though partly &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0012825217303641&quot; rel=&quot;nofollow noreferrer&quot;&gt;speculative&lt;/a&gt; and not good for an &amp;quot;ad-hoc&amp;quot; and general explanation for an orogeny, is that process assumed to be always connected to a continent/continent collision? I found no discussion or proposal in literature about the Andes (Nazca plate subduction), at least not when searching superficially.&lt;/p&gt;&#xA;" OwnerDisplayName="user22279" LastEditorDisplayName="user20559" LastEditDate="2021-05-26T14:05:51.170" LastActivityDate="2021-05-26T14:05:51.170" Title="Slab-breakoff - always connected to continent/continent collision?" Tags="|plate-tectonics|geodynamics|subduction|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21260" PostTypeId="2" ParentId="2189" CreationDate="2021-05-15T13:33:54.490" Score="3" Body="&lt;p&gt;No, generally one cannot determine the date when a rock was broken if there's no more context.&lt;/p&gt;&#xA;&lt;p&gt;But there are methods to determine&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;... the time since the last exposure to sunlight or intense heat. ...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;They are called &lt;a href=&quot;https://www.usgs.gov/centers/gecsc/labs/luminescence-dating-laboratory?qt-science_support_page_related_con=4#qt-science_support_page_related_con&quot; rel=&quot;nofollow noreferrer&quot;&gt;luminescense dating&lt;/a&gt; (source of the quote), are applicable for instance to sediment samples or pebbles that were exposed to fire. If they broke in the fire and were subsequently buried, e.g. in a fireplace of an archeological site, then that event could potentially be dated by OSL or TL.&lt;/p&gt;&#xA;&lt;p&gt;Luminescence methods have considerable uncertainties (~10%) and limits (up to 10 thousands to a few hundred thousands of years), but can be used when radiocarbon dating isn't possible (too old, no organic components in a sample) and other unstable isotope methods aren't applicable either.&lt;/p&gt;&#xA;&lt;p&gt;Be warned though, once exposed to daylight (or heat) the clock in a sample is reset in seconds.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Luminescence_dating&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Luminescence_dating&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user22279" LastActivityDate="2021-05-15T13:33:54.490" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21261" PostTypeId="1" CreationDate="2021-05-16T07:10:35.437" Score="3" ViewCount="470" Body="&lt;p&gt;I have an ODIAC Global CO&lt;sub&gt;2&lt;/sub&gt; emission dataset. The dataset is provided in netCDF (.nc) format and the resolution of the dataset is 1x1 degree. The unit of the dataset is gC/m&lt;sup&gt;2&lt;/sup&gt;/day. I need to convert it into Tonnes.&#xA;The approach I am following is as follows:&lt;/p&gt;&#xA;&lt;p&gt;Suppose we have 7 gC/m&lt;sup&gt;2&lt;/sup&gt;/day CO&lt;sub&gt;2&lt;/sub&gt; emission for a cell/pixel/grid unit. As the resolution of the cell is 1x1 degree we need to convert it to m&lt;sup&gt;2&lt;/sup&gt;.&lt;/p&gt;&#xA;&lt;p&gt;1x1 deg = 111000 × 111000 m&lt;sup&gt;2&lt;/sup&gt; = 1.232×10&lt;sup&gt;10&lt;/sup&gt; m&lt;sup&gt;2&lt;/sup&gt; (Approximately 1 deg = 111 km)&lt;/p&gt;&#xA;&lt;p&gt;7 gC/m&lt;sup&gt;2&lt;/sup&gt;/day = 7 × 1.232 × 10&lt;sup&gt;10&lt;/sup&gt; = 8.624 × 10&lt;sup&gt;10&lt;/sup&gt; gC/day = 8.624 × 10&lt;sup&gt;4&lt;/sup&gt; tonnes/day (1 Tonne = 10&lt;sup&gt;6&lt;/sup&gt; g)&lt;/p&gt;&#xA;&lt;p&gt;Is it correct approach? I am confused about how to deal with the time unit.&lt;/p&gt;&#xA;" OwnerUserId="22420" LastEditorUserId="2470" LastEditDate="2021-05-16T10:57:13.560" LastActivityDate="2021-05-16T10:57:13.560" Title="How to convert CO2 emission from gC/m2/day to Tonnes?" Tags="|climate-models|co2|greenhouse-gases|emissions|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21262" PostTypeId="1" CreationDate="2021-05-16T08:06:15.193" Score="5" ViewCount="184" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7BLho.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7BLho.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EKKEB.png%3Cbr%3E&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EKKEB.png%3Cbr%3E&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Whenever I look up the track of a cyclone on the map, I always notice that the cone of uncertainty bulges as it moves towards land/ target. I have inserted two images to show you what I mean, you could look up any other image but its always the same. Is there any specific reason for this phenomenon?&lt;/p&gt;&#xA;" OwnerUserId="22530" LastActivityDate="2021-05-16T10:46:34.890" Title="Cone of uncertainty in cyclones" Tags="|meteorology|cyclone|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21265" PostTypeId="2" ParentId="21262" CreationDate="2021-05-16T10:46:34.890" Score="2" Body="&lt;p&gt;As the name suggests it is a region of &lt;em&gt;uncertainty&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;There are many uncertainties when modeling and predicting weather systems.&lt;/p&gt;&#xA;&lt;p&gt;When meteorologists model the path of a cyclone/typhoon/hurricane they never know for certain where a cyclone will actually end up. At any point along its path a local variation may cause it speed up, slow down, rotate at a slightly different rate or slightly change its path, left or right.&lt;/p&gt;&#xA;&lt;p&gt;Meteorologists run several models for such cyclone systems on computers. Each uses either a different algorithm and/or different weather parameters. The results of all the models are then used to determine a region where the cyclone is &lt;em&gt;likely&lt;/em&gt; to be in with a given time frame.&lt;/p&gt;&#xA;&lt;p&gt;The greatest &lt;em&gt;certainty&lt;/em&gt; is closest to the cyclone. The further away the projected path is from a cyclone the greater is the &lt;strong&gt;un&lt;/strong&gt;certainty. This results in a larger spread of possible locations where the cyclone could eventually be. When drawn on a map this region looks like a cone.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-05-16T10:46:34.890" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21266" PostTypeId="1" CreationDate="2021-05-16T17:36:02.280" Score="1" ViewCount="49" Body="&lt;p&gt;I am not a geologist/geology student but I want to quickly know the influence of volcanic rock type to geothermal suitability. I have read read some journals and online articles but it seems there are a lot of ways different mappers/researchers name geologic unit. What I am trying to do is rank types of volcanic rocks ex. the legend on the image to most influential to less influential to the geothermal suitability. A direct answer is cool but also welcome articles or readings regarding this. Thanks!&lt;/p&gt;&#xA;&lt;p&gt;Legend:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Hz7uU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Hz7uU.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18953" LastActivityDate="2021-05-16T17:36:02.280" Title="Ranking volcanic rocks influence to geothermal suitability?" Tags="|geology|volcanology|geothermal-heat|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="21267" PostTypeId="2" ParentId="21168" CreationDate="2021-05-16T21:37:15.637" Score="1" Body="&lt;p&gt;When push comes to shove, the highest evaporation rate per unut area corresponds to the highest average temperature.&#xA;As this pair of illustrations from &lt;a href=&quot;https://svs.gsfc.nasa.gov/3652&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA&lt;/a&gt; shows, that would be the &lt;strong&gt;Indian Ocean.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Bh5HQ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/obxOO.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;Simply put, the Indian Ocean misses both polar regions and hits the tropical and subtropical latitudes squarely, so it is warmer overall.  Ergo more evaporation.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2021-05-16T21:37:15.637" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21268" PostTypeId="1" AcceptedAnswerId="21271" CreationDate="2021-05-16T22:53:49.697" Score="23" ViewCount="5891" Body="&lt;p&gt;The Democratic Republic of the Congo's Katanga Province contains almost 40% of the world's reserves of cobalt [1].&lt;/p&gt;&#xA;&lt;p&gt;Why are deposits concentrated so strongly in such a small portion of the earth?&lt;/p&gt;&#xA;&lt;p&gt;I would have thought that this is due to similar reasons to: &lt;a href=&quot;https://earthscience.stackexchange.com/q/2393&quot;&gt;Why do gold deposits form only in certain areas of the earth?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But the distribution of cobalt seems far more uneven than that of gold.&lt;/p&gt;&#xA;&lt;p&gt;Do the geological processes causing this uneven distribution significantly differ from those that cause the uneven distribution of gold?&lt;/p&gt;&#xA;&lt;p&gt;[1]: British geological survey, 2009&lt;/p&gt;&#xA;" OwnerUserId="22535" LastActivityDate="2021-05-18T19:22:45.780" Title="Why are cobalt deposits so unevenly distributed?" Tags="|geology|mining|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="21269" PostTypeId="2" ParentId="349" CreationDate="2021-05-17T03:41:34.357" Score="2" Body="&lt;p&gt;The definition I use is class is.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;A rock is a solid compound composed of one or more mineral or mineraloids.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;its the broadest but also the easiest definition, there are biotic, abiotic, and human created rocks.  To go to chemistry basically any solid is a rock. Sand is a pile of tiny rocks.&lt;/p&gt;&#xA;&lt;p&gt;Some argue that only naturally occurring compounds should count but the usage in literature is pretty obvious. Man made materials are called anthropic rocks in the literature. this has become nessisary ever since since humans started introducing artificial minerals. Fordite, slag, concrete, bricks, glass, ceramics, there are formations composed mostly of anthropic rock now. Some even argue there should be four rock types; metamorphic, sedimentary, igneous, and anthropic.&lt;/p&gt;&#xA;&lt;p&gt;The only real consideration I ever see is the exclusion of living matter (but not dead matter) This can lead you into a great discussion of how there are not real hard categories in nature. Any category humans come up with will get fuzzy around the edges because nature is a continuum not discreet.&lt;/p&gt;&#xA;&lt;p&gt;Of course &amp;quot;mineral or mineraloids&amp;quot; just means a solid of known chemical compositional which case you could shorten it to say, &amp;quot;&lt;strong&gt;a rock is any nonliving solid compound&lt;/strong&gt;&amp;quot;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2021-05-17T03:49:21.187" LastActivityDate="2021-05-17T03:49:21.187" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21270" PostTypeId="2" ParentId="21268" CreationDate="2021-05-17T04:07:00.387" Score="8" Body="&lt;p&gt;Its not that cobalt is less abundant or wide spread. What you are noticing is that &lt;strong&gt;gold has been mined for far longer than cobalt and is far more valuable&lt;/strong&gt;. Gold has been mined even in antiquity and even poor deposits are usually worth extracting, so most of the large easy deposits were mined out ages ago.&lt;/p&gt;&#xA;&lt;p&gt;Cobalt on the the other hand was only discovered in the early 1700's and has far less value. We still have big easy to mine deposits of cobalt and the lesser deposits are not worth mining, so we only mine the easiest places to extract it.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="-1" LastEditDate="2021-05-18T19:22:45.780" LastActivityDate="2021-05-18T19:22:45.780" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21271" PostTypeId="2" ParentId="21268" CreationDate="2021-05-17T05:51:12.113" Score="30" Body="&lt;h2&gt;Part 1&lt;/h2&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Democratic Republic of the Congo's Katanga Province contains&#xA;almost 40% of the world's reserves of cobalt [1].&lt;/p&gt;&#xA;&lt;p&gt;Why are deposits concentrated so strongly in such a small portion of&#xA;the earth?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Cobalt isn't as unevenly distributed as it seems. It is correct that most of the world's cobalt &lt;strong&gt;reserves&lt;/strong&gt; are in DRC, but most of the cobalt &lt;strong&gt;resources&lt;/strong&gt; are not in DRC. And this is a very important point.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Resources&lt;/strong&gt; are known and estimated quantities of economically extractable materials. &lt;strong&gt;Reserves&lt;/strong&gt; are resources for which detailed plans for extraction have been made. This means that to turn a resource into a reserve you need to have plans for the extraction and refining plants, have environmental approval, have the workforce figured out, have authorisation from the owners of the land, and more. As you can guess, making a resource into a reserve is a time consuming and expensive process.&lt;/p&gt;&#xA;&lt;p&gt;The reason why most of the Earth's reserves are in DRC is simply because it's easier and cheaper. The infrastructure already exists, and the expertise exists. At current technology levels and cobalt prices, the investment in defining a reserve from a resource elsewhere is simply not economical.&lt;/p&gt;&#xA;&lt;p&gt;This does not mean that DRC has most of the cobalt. It only means that getting cobalt out of the ground and making it into a product is cheaper in DRC than it is in other countries.&lt;/p&gt;&#xA;&lt;h2&gt;Part 2&lt;/h2&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Do the geological processes causing this uneven distribution significantly differ from those that cause the uneven distribution of gold?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The reasons are the same, in principle. Every element behaves differently and will separate from other elements and concentrate because of various geological processes. Cobalt tends to follow copper and nickel, and in most cases it is mined as a by-product of those elements. That's why cobalt is extracted from the African &lt;strong&gt;Copper&lt;/strong&gt;belt, and why it's extracted from nickel deposits in Australia. Not much point going into the chemistry and thermodynamics of why this happens, but the point is that elements which are concentrated by rare geological processes will be found in fewer places, and elements that are concentrated by common geological processes will be found in more places.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-05-17T05:51:12.113" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="21272" PostTypeId="2" ParentId="21259" CreationDate="2021-05-17T10:16:07.880" Score="1" Body="&lt;p&gt;Slab break off happens also during arc volcanic-continent collisions.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://onlinelibrary.wiley.com/doi/abs/10.1046/j.1365-3121.2002.00387.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;Andes is not an exception&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastActivityDate="2021-05-17T10:16:07.880" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21273" PostTypeId="1" CreationDate="2021-05-17T14:44:46.087" Score="3" ViewCount="68" Body="&lt;p&gt;Suppose, Venus becomes tidally locked. Will its dark side cool enough so that the CO&lt;sub&gt;2&lt;/sub&gt; from atmosphere to precipitate in liquid form to make an ocean?&lt;/p&gt;&#xA;" OwnerUserId="2819" LastEditorUserId="2470" LastEditDate="2021-05-18T05:14:26.707" LastActivityDate="2021-05-20T15:29:58.767" Title="Climate on Venus after it becomes tidally locked" Tags="|atmosphere|planetary-science|climate-models|atmosphere-modelling|climatology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21274" PostTypeId="1" AcceptedAnswerId="22412" CreationDate="2021-05-17T15:17:57.110" Score="4" ViewCount="129" Body="&lt;p&gt;I once learned in high school that the area where I used to live experiences the Coriolis effects of the air movement above the city. I never paid attention to this before, but I recently heard about it again, and I have no idea if it is true or not. There is absolutely no way I can validate that theory by using the wider definition of the Coriolis effect, but I do have access to a wind rose which looks like in the graph below:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/a1am6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/a1am6.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Is there any way to understand if there are any Coriolis-like winds by using this graph or a similar one? I found a nice sketch of this effect online, but I fail to understand how to correlate these two.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jitkN.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jitkN.png&quot; alt=&quot;http://www.pas.rochester.edu/~blackman/ast104/coriolis.html&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Is there anyone who could help me to understand if one can get this effect from a wind-rose?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="21858" LastEditorUserId="21858" LastEditDate="2021-05-17T15:46:41.133" LastActivityDate="2021-06-17T20:06:53.797" Title="Is it possible to detect Coriolis effect using a Wind Rose?" Tags="|meteorology|geography|wind|coriolis|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21276" PostTypeId="2" ParentId="21274" CreationDate="2021-05-17T15:48:28.450" Score="0" Body="&lt;p&gt;Yes, your figure is correct: in the mid-latitudes we have cyclones and anticyclones. They can't exist on equator because the Coriolis force there is too small to keep them stable. But the cyclones or anticyclones are present all around your country and their effects cancel each other. So, you can't determine the presence of Coriolis force on such micro scale. Otherwise, the effect of spining anticyclones and cyclones isn't specific to your country, but is (as previously stated) present over whole mid-latitudes. Also, the Coriolis effect isn't acting on microswirls because the Coriolis parameter is so small (due to too slow Earth's rotation).&lt;/p&gt;&#xA;" OwnerUserId="19122" LastEditorUserId="19122" LastEditDate="2021-06-17T07:27:41.033" LastActivityDate="2021-06-17T07:27:41.033" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21279" PostTypeId="2" ParentId="21273" CreationDate="2021-05-18T01:11:42.533" Score="2" Body="&lt;p&gt;While Venus is not tidally locked to the sun, it rotates slow enough that you might as well consider it tidally locked.&lt;/p&gt;&#xA;&lt;p&gt;However you have to disentangle the slow rotation from the superrotating atmospheric motion. The fast atmospheric rotation (as reaction of the atmospheric gases to the intense solar radiation) redistributes heat very efficiently in the upper atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;In the &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Venus#Troposphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;lower atmosphere,&lt;/a&gt; no significant winds are observed, but the atmosphere has a large density, which through heat conduction again makes redistribution of heat efficient.&lt;/p&gt;&#xA;&lt;p&gt;All in all, Venus' atmosphere has therefore a horizontally uniform temperature. Said differently, next to no dayside-nightside temperature gradients exist. Nothing will precipitate.&lt;/p&gt;&#xA;&lt;p&gt;Furthermore the &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; at the surface is superfluid due to the intense pressure, and this state doesn't seem to form droplets, it IS a sort of highly-viscous &lt;span class=&quot;math-container&quot;&gt;$CO_2 $&lt;/span&gt;-ocean.&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="2470" LastEditDate="2021-05-18T05:16:00.830" LastActivityDate="2021-05-18T05:16:00.830" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="21282" PostTypeId="2" ParentId="14558" CreationDate="2021-05-18T21:35:33.207" Score="5" Body="&lt;p&gt;According to &lt;a href=&quot;https://books.google.co.uk/books?hl=en&amp;amp;lr=&amp;amp;id=tF1-AV_bqDkC&amp;amp;oi=fnd&amp;amp;pg=PA8&amp;amp;ots=JCSNCY8WqR&amp;amp;sig=ZrryQEeWhymiOSashcjF2tCmoGs&amp;amp;redir_esc=y#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ultraviolet Radiation, Human Health, and the Urban Forest&lt;/a&gt; it would seem at least the general shape you obtained is correct:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/XpoxH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XpoxH.png&quot; alt=&quot;UVB irradiance on south-facing surfaces with clear skies at solar noon on the 21st of each month for the five cities listed in figure 5&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here they tracked the irradiance at noon over different months of the year not hours of the day, but the basic change is the same: high to low to high Solar Zenith Angle when irradiating a vertical surface leads to an irradiance graph with 2 &amp;quot;shoulders&amp;quot; on both sides of the maximum solar elevation point. The irradiance is lower at the central point because the direct rays are parallel to the target surface and the only contribution are the scattered and reflected rays from the environment and the rest of the sky, and then as the SZA progresses more and more toward 90 degrees (or elevation toward 0 degrees) the increasing atmospheric absorbance comes into play and reduces the irradiation long before the rays become exactly perpendicular to the target surface.&lt;/p&gt;&#xA;&lt;p&gt;But if the goal of the UV Index was to provide safety data for the general public, I would say it should've been measured assuming the absolute worst-case scenario of some unprotected skin being exposed to exactly perpendicular solar rays at &lt;em&gt;any&lt;/em&gt; hour of the day (this is possible because our bodies have complex surfaces and it's always possible to have at least a little skin that's perpendicular to almost any ray direction in all of 3D space). So they should've used a detector that is rotated to face the sun at all hours of the day, and the resulting graph I suspect would not look like the official daily UV Index graph but also not like the &amp;quot;2 shoulders&amp;quot; one we have here. It would probably look more like the &amp;quot;IND&amp;quot;, &amp;quot;SYR&amp;quot; and &amp;quot;INL&amp;quot; variants in the image above: a sort of &amp;quot;Gaussian with a wider top&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;LE: Here we go, it should look like the &lt;strong&gt;D&lt;/strong&gt;irect &lt;strong&gt;N&lt;/strong&gt;ormal &lt;strong&gt;I&lt;/strong&gt;rradiance curve, with no cosine correction for horizontal receiving surfaces: &lt;a href=&quot;https://www.researchgate.net/figure/Direct-normal-irradiance-vs-solar-time-at-Izana-Tenerife-Kaashidhoo-Maldives-and_fig1_236314638&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/figure/Direct-normal-irradiance-vs-solar-time-at-Izana-Tenerife-Kaashidhoo-Maldives-and_fig1_236314638&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22510" LastEditorUserId="22510" LastEditDate="2021-05-26T12:40:07.020" LastActivityDate="2021-05-26T12:40:07.020" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21283" PostTypeId="1" CreationDate="2021-05-19T18:26:05.110" Score="3" ViewCount="372" Body="&lt;p&gt;My 7 year old son found this fossil whilst cracking open flint in Deal, Kent.&#xA;The fossil (assuming it is) looks like scales/cells/shell and is chalky. The oblong lines are raised and well defined and tough to the touch. It certainly looks like a natural biological pattern.&#xA;It looks very a little smaller than a golf ball stuck in the flint. Its edges disappear under the flint with the appearance that it is a sphere.&#xA;Be glad if anyone has an idea. Thanks[![enter image description here][1]][1]&lt;/p&gt;&#xA;&lt;p&gt;[1]: &lt;a href=&quot;https://i.stack.imgur.com/ye4XU.jpg!%5Benter&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://i.stack.imgur.com/ye4XU.jpg![enter&lt;/a&gt; image description here](&lt;a href=&quot;https://i.stack.imgur.com/byNAu.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://i.stack.imgur.com/byNAu.jpg&lt;/a&gt;)&lt;img src=&quot;https://i.stack.imgur.com/btSdC.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;img src=&quot;https://i.stack.imgur.com/Y3sT3.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;img src=&quot;https://i.stack.imgur.com/JwK90.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;" OwnerUserId="22569" LastEditorUserId="22569" LastEditDate="2021-05-23T16:38:55.540" LastActivityDate="2021-06-30T18:13:42.980" Title="What is this fossil found in flint in Kent?" Tags="|rocks|fossils|paleontology|identification-request|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="21284" PostTypeId="2" ParentId="21099" CreationDate="2021-05-20T17:48:46.367" Score="1" Body="&lt;p&gt;The following paragraphs are reproduced from &lt;a href=&quot;https://www.nationalgeographic.org/encyclopedia/core/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nationalgeographic.org/encyclopedia/core/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Growth in the Inner Core&lt;/p&gt;&#xA;&lt;p&gt;As the entire Earth slowly cools, the inner core grows by about a millimeter every year. The inner core grows as bits of the liquid outer core solidify or crystallize. Another word for this is “freezing,” although it’s important to remember that iron’s freezing point more than 1,000° Celsius (1,832° Fahrenheit).&lt;/p&gt;&#xA;&lt;p&gt;The growth of the inner core is not uniform. It occurs in lumps and bunches, and is influenced by activity in the mantle.&lt;/p&gt;&#xA;&lt;p&gt;Growth is more concentrated around subduction zones—regions where tectonic plates are slipping from the lithosphere into the mantle, thousands of kilometers above the core. Subducted plates draw heat from the core and cool the surrounding area, causing increased instances of solidification.&lt;/p&gt;&#xA;&lt;p&gt;Growth is less concentrated around “superplumes” or LLSVPs. These ballooning masses of superheated mantle rock likely influence “hot spot” volcanism in the lithosphere, and contribute to a more liquid outer core.&lt;/p&gt;&#xA;&lt;p&gt;The core will never “freeze over.” The crystallization process is very slow, and the constant radioactive decay of Earth’s interior slows it even further. Scientists estimate it would take about 91 billion years for the core to completely solidify—but the sun will burn out in a fraction of that time (about 5 billion years).&amp;quot;&lt;/p&gt;&#xA;" OwnerUserId="22580" LastActivityDate="2021-05-20T17:48:46.367" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21285" PostTypeId="1" CreationDate="2021-05-20T19:06:44.550" Score="1" ViewCount="102" Body="&lt;p&gt;Note: I know this question sounds fit for aviation stack exchange, but other aspects of this question like cloud formation, atmospheric behavior, precipitation and overall water cycle can be better answered here.&lt;/p&gt;&#xA;&lt;p&gt;There are &lt;a href=&quot;https://www.airbus.com/newsroom/press-releases/en/2020/09/airbus-reveals-new-zeroemission-concept-aircraft.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;aviation&lt;/a&gt; manufacturers which are working towards bringing aircrafts fueled with Hydrogen that only/mostly release water vapor (&lt;em&gt;as the major exhaust component&lt;/em&gt;). Now, if it proves to be true and safe enough, is it possible to facilitate artificial precipitation in the areas above which the airplanes fly over a period of months, thereby creating enough cloud paths that eventually cause rains.&lt;/p&gt;&#xA;&lt;p&gt;Can we possibly make areas like Sahara Green using this methodology?&lt;/p&gt;&#xA;" OwnerUserId="22476" LastActivityDate="2021-05-21T16:51:58.973" Title="Hypothetical: Can we rehabilitate arid/desert landscapes through the artificial precipitation from exhausts of hydrogen powered airplanes?" Tags="|water|precipitation|desert|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21286" PostTypeId="2" ParentId="21285" CreationDate="2021-05-20T23:14:26.017" Score="0" Body="&lt;p&gt;Making the Sahara Green would be almost Impossible, The Sahara is naturally dry due to Rotation Patterns, In fact, the Sahara was once green, maybe the technique you presented would work for Small Deserts which are caused by Climate change.&lt;/p&gt;&#xA;&lt;p&gt;There are click-bait articles that disagree with me, &lt;a href=&quot;https://scoutmagazine.ca/2019/05/30/what-would-happen-if-we-attempted-to-terraform-the-sahara-desert/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This one talks about turning the Sahara into a rainforest which is laughable to me.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Otherwise, terraforming the Sahara is off the list. One comment on the article reads, &amp;quot;I think they should just move around those city’s then and do the rest of the Sahara and change it to a rain forest.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;@lousycoder but I think the methodology you presented is smart. The Sahara is huge, you would need a lot of planes and it will have a big price tag, and im sure some countries aren't interested in terraformation.&lt;/p&gt;&#xA;" OwnerUserId="21926" LastActivityDate="2021-05-20T23:14:26.017" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21287" PostTypeId="1" AcceptedAnswerId="21293" CreationDate="2021-05-21T00:52:25.900" Score="4" ViewCount="85" Body="&lt;p&gt;I am a lay person in meteorology, maybe this is not the right place for my question, but I would like to ask then.&lt;/p&gt;&#xA;&lt;p&gt;My question is simple: is there a website or institute that has integrated statistics on forecasting the occurrence of rainbows in different countries around the world?&lt;/p&gt;&#xA;" OwnerUserId="22582" LastActivityDate="2021-06-04T04:22:18.897" Title="Some website or institute with integrated statistics on forecasting the occurrence of rainbows" Tags="|meteorology|weather-forecasting|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21288" PostTypeId="2" ParentId="21285" CreationDate="2021-05-21T01:14:26.770" Score="1" Body="&lt;p&gt;Jet fuel is hydrocarbons, so their exhaust is partly water, which is responsible for the visible contrails. &lt;a href=&quot;https://e360.yale.edu/features/how-airplane-contrails-are-helping-make-the-planet-warmer&quot; rel=&quot;nofollow noreferrer&quot;&gt;How Airplane Contrails Are Helping Make the Planet Warmer&lt;/a&gt; suggests that the main climate effect is warming, not rain.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2021-05-21T01:14:26.770" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21289" PostTypeId="1" CreationDate="2021-05-21T13:41:23.230" Score="1" ViewCount="45" Body="&lt;p&gt;I'm sometimes frustrated by publicly available precipitation forecasts, such as those offered by the Met Office or Google. If I understand these forecasts correctly, they tell me:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The expected volume of rain (e.g. 5ml of rain)&lt;/li&gt;&#xA;&lt;li&gt;The overall likelihood of there being any rain (e.g. 50% chance of rain)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;This is generally a sufficient level of data, but sometimes it would be useful to see a more statistically nuanced prediction, which could let me know things like:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The 95% confidence interval of the expected volume of rain&lt;/li&gt;&#xA;&lt;li&gt;A probability-density of rainfall volume&lt;/li&gt;&#xA;&lt;li&gt;Maximum/minimum possible volume within a given interval of confidence&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Is there any rainfall data of that sort available for the UK?&lt;/p&gt;&#xA;" OwnerUserId="22584" LastActivityDate="2021-05-24T20:42:38.103" Title="Is there any open source, stochastic rain forecast data available for the UK?" Tags="|meteorology|weather-forecasting|precipitation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21290" PostTypeId="2" ParentId="21285" CreationDate="2021-05-21T16:51:58.973" Score="3" Body="&lt;p&gt;Rough calculations: A 747 burns about 10000 kg of fuel an hour. Assuming it burned hydrogen at the same rate it would produce about 100000 kg (or litres) of water an hour. Flying at 1000 km/hr that means it produces 100 litres of water per kilometre of flight, or 0.1 litre of water per metre.  Lets assume all of this water drops vertically below the plane in a path 100 metres wide. That means that we have 0.001 litres/m&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt; of water, equivalent to 0.001 millimeter of rainfall. The plane could then turn around and repeat the pass, so in a 10 hour working day we could have 0.01 mm of rainfall&lt;/p&gt;&#xA;&lt;p&gt;If we take a threshold of desert very conservatively at 200 mm rain per annum, and fly our plane backwards and forwards along a 1000 kilometre path for 10 hours a day, 5 days a week, it would only create 2 mm of rainfall a year. So to get 'non-desert' along our 100 metre wide strip of desert we would need to fly 100 planes every day!&lt;/p&gt;&#xA;&lt;p&gt;Looked at another way. The Aswan dam in Egypt irrigates an area of 300,000 square kilometres. The dam releases about 50 cubic kms of water per year. 50 cubic kms  is 5 x 10&lt;span class=&quot;math-container&quot;&gt;$^{13}$&lt;/span&gt; litres of water. Our plane produces 10&lt;span class=&quot;math-container&quot;&gt;$^5$&lt;/span&gt; litres per hour, so we would need 10&lt;span class=&quot;math-container&quot;&gt;$^8$&lt;/span&gt; , or 100 million, hours of flight to produce the same volume.  That would be 100,000 jumbo jets flying 24 hours a day, 365 days a year to irrigate an area equivalent to 3% of the area of the Sahara.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2021-05-21T16:51:58.973" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21293" PostTypeId="2" ParentId="21287" CreationDate="2021-05-22T04:33:57.590" Score="5" Body="&lt;p&gt;A rainbow is not a physical object that has a position.  It is an optical phenomena that depends on your location relative to the sun and rain.  If you are standing where your eyes can intercept the colored light, you are standing with your back to the sun and the sunlight is reflecting on raindrops in front of you.  Someone else standing in a different location would not necessarily see a rainbow if they looked up at the same part of the sky.&lt;/p&gt;&#xA;&lt;p&gt;From &lt;a href=&quot;http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/opt/wtr/rnbw/frm.rxml&quot; rel=&quot;nofollow noreferrer&quot;&gt;University of Illinois&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;According to Descartes' calculations using laws of optics, the three stage refraction-reflection-refraction pattern that light undergoes when passing through a raindrop produces a concentration of outgoing rays along a line that is 42 degrees above the head of an observer's shadow. This concentration of light rays is the rainbow that we see.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Also &lt;a href=&quot;https://www.nationalgeographic.org/encyclopedia/rainbow/print/#:%7E:text=In%20fact%2C%20no%20one%20sees,his%20or%20her%20own%20horizon.&quot; rel=&quot;nofollow noreferrer&quot;&gt;this National Geographic article&lt;/a&gt; has a nice description:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Viewers on the ground can only see the light reflected by raindrops above the horizon. Because each person's horizon is a little different, no one actually sees a full rainbow from the ground. In fact, no one sees the same rainbow—each person has a different antisolar point, each person has a different horizon. Someone who appears below or near the &amp;quot;end&amp;quot; of a rainbow to one viewer will see another rainbow, extending from his or her own horizon.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;What this means is that a rainbow is not really a meteorological occurrence that can be measured or catalogued, because you would get a different answer depending on your reference point.  Lightning, in contrast, is a physical phenomena that has a precise location which can be determined and verified from multiple points of reference.&lt;/p&gt;&#xA;&lt;p&gt;Rainbows are photographed and archived by enthusiasts, but it's really about artistic appreciation.  While I have not looked into rainbow forecast services, a quick search shows some interesting resources, such as &lt;a href=&quot;https://stephenbayphotography.com/blog/how-to-predict-rainbows-and-plan-photographs/&quot; rel=&quot;nofollow noreferrer&quot;&gt;How to Predict Rainbows and Plan Photographs&lt;/a&gt; which has a link to a &lt;a href=&quot;https://www.planitphoto.com/#feature&quot; rel=&quot;nofollow noreferrer&quot;&gt;photography app that can plan for rainbows&lt;/a&gt; and here is a &lt;a href=&quot;http://www.erikscarlson.com/project/chance-of-rainbow#:%7E:text=Creating%20an%20algorithm%20to%20predict,(if%20that%20is%20possible).&quot; rel=&quot;nofollow noreferrer&quot;&gt;rainbow app you can install&lt;/a&gt; on your phone.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.rebeccapaton.net/rainbows/formatn.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;How Rainbows Happen&lt;/a&gt; also has a nice description (shown below) and some other useful resources.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/GEDyn.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GEDyn.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2021-06-04T04:22:18.897" LastActivityDate="2021-06-04T04:22:18.897" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21294" PostTypeId="1" CreationDate="2021-05-22T10:55:44.073" Score="5" ViewCount="157" Body="&lt;p&gt;I found this fossil while doing my fieldwork in limestone area. Description below may help to identify it.&lt;/p&gt;&#xA;&lt;p&gt;Location: NW Perlis, Malaysia (Setul Formation). Hilly Area.&lt;/p&gt;&#xA;&lt;p&gt;My Observation:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Have a curly shape&lt;/li&gt;&#xA;&lt;li&gt;It have line and look like a suture&lt;/li&gt;&#xA;&lt;li&gt;Does not have visible feature of cephalopod like septa and chamber.&lt;/li&gt;&#xA;&lt;li&gt;It can be found between layer of stromatolite&lt;/li&gt;&#xA;&lt;li&gt;Other fossil found nearby: gastropod, cephalopod and brachiopod (most of this fossil already have been damage but the shape still good and can easily identify it.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Size of the coin: 2.2 cm.&lt;/p&gt;&#xA;&lt;p&gt;I hope this information is helping to identify the fossil. Thanks.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Rrenu.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Rrenu.jpg&quot; alt=&quot;Plan View of the fossil and its has curly shape&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vDXat.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vDXat.jpg&quot; alt=&quot;Look like a suture&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VrCcn.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VrCcn.jpg&quot; alt=&quot;The &amp;quot;suture&amp;quot; still can be seen from the inside&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20671" LastEditorUserId="20671" LastEditDate="2021-05-22T14:04:43.373" LastActivityDate="2021-07-25T01:51:24.893" Title="Fossil ID: possible fauna fossil, from Perlis, Malaysia" Tags="|geology|fossils|paleontology|carbonate|identification-request|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="21295" PostTypeId="1" CreationDate="2021-05-22T23:08:59.473" Score="3" ViewCount="80" Body="&lt;p&gt;I know this sounds basic but I've wondered about this for a long time and I'm &lt;em&gt;still&lt;/em&gt; confused.&lt;/p&gt;&#xA;&lt;p&gt;In aviation, air speed is ground speed minus wind speed. If wind speed is zero, air speed equals ground speed.&lt;/p&gt;&#xA;&lt;p&gt;But the earth is rotating 360 deg/day. At sea level this rotation imparts to you an eastward linear velocity of just over 400 m/s. The atmosphere is generally close to static at the surface, so the air moves at this speed also with the rest of us.&lt;/p&gt;&#xA;&lt;p&gt;But what happens at 25 km above ground? If all winds magically disappeared, would you find the air move eastward at &amp;gt;400 m/s (with a tiny correction for the increased elevation of 6360 + 25 km instead of just 6360 km at sea level)?&lt;/p&gt;&#xA;&lt;p&gt;This seems to be a requirement if air speed is to be calculated as ground speed + wind speed, since both speeds need to be relative to the same reference (the ground), so I want to say yes... but can someone confirm or dispute?&lt;/p&gt;&#xA;&lt;p&gt;Thanks! And apologies for littering with basic questions like this. I should know this, but I don't.&lt;/p&gt;&#xA;" OwnerDisplayName="user22590" LastActivityDate="2021-05-25T12:09:07.723" Title="Would the atmosphere move rigidly with ground if you ignored wind?" Tags="|wind|atmosphere-modelling|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21296" PostTypeId="1" AcceptedAnswerId="22369" CreationDate="2021-05-23T01:18:17.677" Score="5" ViewCount="183" Body="&lt;p&gt;&lt;a href=&quot;http://tao.cgu.org.tw/index.php/articles/archive/atmospheric-science/item/1171&quot; rel=&quot;noreferrer&quot;&gt;A 300-Year Typhoon Record in Taiwan and the Relationship with Solar Activity&lt;/a&gt; (also &lt;a href=&quot;http://140.112.66.168/tao/media/k2/attachments/v244-IIp737.pdf&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;) shows that about 30% of all typhoons in the western north pacific (WNP) affect Taiwan. (Author's &lt;a href=&quot;http://www1.geo.ntnu.edu.tw/%7Ecwhung/&quot; rel=&quot;noreferrer&quot;&gt;home page&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;I'm not sure how &amp;quot;affect&amp;quot; is defined there, but there are certainly a lot of them, and Taiwan depends on them. This spring there is a serious shortage of water in reservoirs &lt;strong&gt;due to an inadequate number of typhoons in the last year or two.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Why do 30% of all typhoons in the western north pacific (WNP) affect Taiwan? What is it that seems to focus typhoons towards Taiwan?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ishGF.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ishGF.png&quot; alt=&quot;Fig. 3. The ratio of the number of typhoons affecting Taiwan to the total number of typhoons over the WNP. &quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Fig. 3. The ratio of the number of typhoons affecting Taiwan to the total number of typhoons over the WNP. (a) The yearly values and the 11-year running means are shown as a bar and red line, respectively. (b) The 10-year accumulated ratio for (a). “std” refers to the standard deviations for the ratio.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XNI73.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XNI73.jpg&quot; alt=&quot;An Inventory of Tropical Cyclone Tracks https://www.ncei.noaa.gov/news/inventory-tropical-cyclone-tracks&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.ncei.noaa.gov/news/inventory-tropical-cyclone-tracks&quot; rel=&quot;noreferrer&quot;&gt;An Inventory of Tropical Cyclone Tracks&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2021-05-23T01:27:10.157" LastActivityDate="2021-06-11T04:38:06.760" Title="Why do 30% of all typhoons in the western north pacific (WNP) affect Taiwan?" Tags="|meteorology|tropical-cyclone|severe-weather|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="21297" PostTypeId="1" AcceptedAnswerId="21312" CreationDate="2021-05-23T02:18:47.417" Score="2" ViewCount="178" Body="&lt;p&gt;&lt;a href=&quot;https://astronomy.stackexchange.com/a/43899/7982&quot;&gt;This answer to &lt;em&gt;Why is the magnetic axis of Uranus and Neptune off center?&lt;/em&gt;&lt;/a&gt; in Astronomy SE perplexes me, partly because I can't understand the block quotes and partly because they constrast those planets with Earth and Earth's dipole &lt;a href=&quot;https://space.stackexchange.com/a/34696/12102&quot;&gt;is off center&lt;/a&gt; as well and it's field also flips back and forth.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Is it possible to write a simplified, plain-language summary of what this explanation for why Uranus and Neptune are different than Earth in having large offsets of their dipole field?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;From the linked answer, which is sourced from Nellis 2017 &lt;a href=&quot;https://iopscience.iop.org/article/10.1088/1742-6596/950/4/042046&quot; rel=&quot;nofollow noreferrer&quot;&gt;Magnetic fields of Uranus and Neptune: Metallic fluid hydrogen&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Earth's axisymmetric magnetic field&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;The most researched magnetic field in our Solar System is, of course, Earth. Nellis 2017 explains how coupling between the rotational motion and convective dynamo motions in the Earth's outer core cause the magnetic axis to drive towards alignment to the spin axis:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Because rotational motion (RM) of Earth is strongly coupled into convective dynamo (CD) motions of its fluid-Fe outer core, planetary RM stabilizes convective motions that generate a dipolar magnetic field. If a convective fluctuation occurs which tends to destabilize a given dipolar axis, then strong RM-CD coupling either drives convective motions that essentially restore the initial orientation or CD fluctuations that drive the initial magnetic axes out of orientational equilibrium are so strong that RM-CD coupling eventually drives the dipolar axis into an alignment anti-parallel to its initial one.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Uranus/Neptune non-axisymmetric magnetic fields&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;The magnetic generation near the surface, as well as the H-HE envelope (again according to Nellis) means that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;local convective dynamo motions of fluids that produce the magnetic fields are essentially decoupled from global rotational motions [...]. The dynamos of U/N would then be relatively free to wander as local convective fluctuations dictate.  Thus, tilt angles and center-offsets of their fields would vary slowly over the age of the Solar System.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2021-05-26T21:08:30.660" Title="Plain-language summary of why Uranus and Neptune are different than Earth in having large offsets of their dipole field?" Tags="|planetary-science|geomagnetism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21298" PostTypeId="1" AcceptedAnswerId="21299" CreationDate="2021-05-23T05:38:28.563" Score="3" ViewCount="344" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JsTmv.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JsTmv.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I see cirrocumulus fading away in the front and bunch of cirrostratus in the back. However, I was taught that cirrocumulus appear when the upper atmosphere is unstable while cirrostratus appear when the atmosphere is stable, so seeing both together is confusing.&lt;/p&gt;&#xA;" OwnerUserId="22031" LastEditorUserId="543" LastEditDate="2021-05-28T03:27:07.890" LastActivityDate="2021-05-28T03:27:07.890" Title="Can Cirrocumulus and Cirrostratus appear at the same time?" Tags="|meteorology|atmosphere|clouds|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21299" PostTypeId="2" ParentId="21298" CreationDate="2021-05-23T15:59:18.303" Score="3" Body="&lt;p&gt;Clouds don't really form in a fully stable atmosphere, so the distinction between &amp;quot;stable&amp;quot; and &amp;quot;unstable&amp;quot; is not real here. An approaching warm front in particular offers many types of clouds, and among other types one may well see high-altitude cirrus, cirrocumulus and cirrostratus clouds appearing together.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Beach weather approaching ... but first:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Warm_front&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia &lt;/a&gt; gives the following description of the wide variety of clouds that may appear in the case of an approaching warm front.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Cirrus, cirrostratus, altostratus, nimbostratus, then stratus. Other clouds can also often be seen, including cirrocumulus amongst the approaching cirrus, altocumulus with or instead of altostratus (particularly if the front is weak), and occasionally cumulonimbus along with or instead of nimbostratus in summer. Additionally, stratocumulus often appears underneath the main altostratus deck and stratus fractus typically forms in precipitation falling from the thick nimbostratus layer. Often in warm temperatures, rain bearing cumulus congestus clouds can appear under the cirrostratus, and more rarely altocumulus castellanus clouds if convection is sufficient. In cold humid conditions, low airmass stratus or fog may obscure the main frontal clouds.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;A picture from the article, showing the major cloud types:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/MR6mb.png&quot; alt=&quot;enter image description here&quot; /&gt;&#xA;Source: &lt;a href=&quot;https://commons.m.wikimedia.org/wiki/File:Warm_front.svg#mw-jump-to-license&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://commons.m.wikimedia.org/wiki/File:Warm_front.svg#mw-jump-to-license&lt;/a&gt;. By WP user Kelvinsong.  License in link.&lt;/p&gt;&#xA;&lt;p&gt;We see that the cirrus and cirtostratus clouds are adjacent, and from the table entry quoted above that cirrocumulus clouds can appear among the cirrus clouds.  Since in reality some overlap will occur between the different cloud regions, an approaching warm front is likely to produce a region where cirrus, cirrocumulus, and cirristratus clouds can be seen together.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2021-05-27T15:46:53.553" LastActivityDate="2021-05-27T15:46:53.553" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21301" PostTypeId="1" CreationDate="2021-05-23T21:02:43.130" Score="2" ViewCount="70" Body="&lt;p&gt;For example, sunlight captured by plants would count in the &amp;quot;arrived as sunlight&amp;quot; category, whilst heat energy in the core of the earth would count in the &amp;quot;kinetic energy during formation&amp;quot; category.&lt;/p&gt;&#xA;" OwnerUserId="22599" LastEditorUserId="22599" LastEditDate="2021-05-23T21:08:14.303" LastActivityDate="2021-05-26T17:32:47.463" Title="How much of all current energy on earth arrived as sunlight vs. as kinetic energy during formation?" Tags="|geophysics|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21303" PostTypeId="2" ParentId="21283" CreationDate="2021-05-24T04:44:21.457" Score="9" Body="&lt;p&gt;That is a sea urchin (echinoid) or at least part of one. the pattern of plates is fairly distinctive. 2 rows of small plates alternating with 2 rows of large plates. I am not familiar enough with urchin phylogeny to give you species but you might be able ot get it from the biology stack.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/g32qN.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/g32qN.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2021-05-24T04:49:50.647" LastActivityDate="2021-05-24T04:49:50.647" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21305" PostTypeId="1" CreationDate="2021-05-24T11:23:53.893" Score="1" ViewCount="70" Body="&lt;p&gt;I researched how mid lattitude cyclones form and found it has to do with the jet stream, which is above the polar front. The pressure difference between the warm and cold air causes a pressure gradient and is tilted to the right due to the coriolis effect.&lt;/p&gt;&#xA;&lt;p&gt;How does the jet stream affect weather (e.g. cyclones) in europe? How is it related to the divergence in the jet stream? Also, why is the divergence aloft created? Thanks a lot.&lt;/p&gt;&#xA;" OwnerUserId="21540" LastEditorUserId="543" LastEditDate="2021-05-27T15:44:28.427" LastActivityDate="2021-05-27T15:44:28.427" Title="How does the jet stream affect weather in Europe?" Tags="|meteorology|pressure|cyclone|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21306" PostTypeId="2" ParentId="21289" CreationDate="2021-05-24T20:42:38.103" Score="3" Body="&lt;p&gt;Well there is ensemble data that you can use. For the UK, you can probably use the &lt;a href=&quot;https://www.ecmwf.int/en/forecasts/dataset/atmospheric-model-ensemble-15-day-forecast#III-i-a&quot; rel=&quot;nofollow noreferrer&quot;&gt;ECMWF ensemble prediction system data&lt;/a&gt; or &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/model-data/model-datasets/global-ensemble-forecast-system-gefs&quot; rel=&quot;nofollow noreferrer&quot;&gt;GEFS&lt;/a&gt; from the US NWS. Both are global models, so they can be extended beyond their respective centers.&lt;/p&gt;&#xA;&lt;p&gt;These ensembles can be used as samples of the probability density function. Normally (pun unintended), with these types of ensembles, the pdf can be assumed to take the form of a Gaussian distribution per ensemble filters. Obviously, this is problematic, as it implies a probability that there is negative precipitation, which is unrealistic. However, if you want to be clever, you can probably fit a kernel to the data. Or you could choose your own distribution. The distribution that is most widely used is the &lt;a href=&quot;https://journals.ametsoc.org/view/journals/atsc/76/11/jas-d-18-0343.1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gamma distribution&lt;/a&gt;, though &lt;a href=&quot;https://hess.copernicus.org/articles/22/6519/2018/hess-22-6519-2018.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Pearson distribution has been shown to perform well too&lt;/a&gt;. &lt;a href=&quot;https://en.wikipedia.org/wiki/Kolmogorov%E2%80%93Smirnov_test&quot; rel=&quot;nofollow noreferrer&quot;&gt;Perhaps using the Kolmogorov-Smirnov test could help you determine which distribution is best.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-05-24T20:42:38.103" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21307" PostTypeId="2" ParentId="21301" CreationDate="2021-05-25T10:02:14.690" Score="1" Body="&lt;p&gt;We can try to compare sunlight energy arriving from the Sun and geothermic energy coming from the Earth's interior.&lt;/p&gt;&#xA;&lt;p&gt;The Earth gets about 340 W/m&lt;sup&gt;2&lt;/sup&gt; from the Sun&lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_energy_budget#/media/File:The-NASA-Earth%27s-Energy-Budget-Poster-Radiant-Energy-System-satellite-infrared-radiation-fluxes.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;(1)&lt;/a&gt; while the average geothermic flux is about 0.1 W/m&lt;sup&gt;2&lt;/sup&gt;.&lt;a href=&quot;https://en.wikipedia.org/wiki/Geothermal_power#Resources&quot; rel=&quot;nofollow noreferrer&quot;&gt;(2)&lt;/a&gt; Therefore, the current energy of sunlight is way larger than that from kinetic energy during Earth formation.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, it should be noted that a large part of geothermic energy doesn't come from Earth cooling by getting rid of its formation heat but from radioactive decay, making the comparison with sunlight even more one sided.&lt;/p&gt;&#xA;" OwnerUserId="6550" LastEditorUserId="6550" LastEditDate="2021-05-26T17:32:47.463" LastActivityDate="2021-05-26T17:32:47.463" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21308" PostTypeId="2" ParentId="21295" CreationDate="2021-05-25T12:09:07.723" Score="3" Body="&lt;p&gt;I think you’re mixing up frames of reference a bit here.  That ~400 m/s speed of the surface is relative to an absolute, non-rotating frame of reference in which an observer sees the Earth as spinning on its axis.  In meteorology we typically use a rotating frame of reference that spins with the Earth, in which an observer sees the surface as moving at 0 m/s.  When we talk about wind, we talk about air motion relative to this rotating frame.  You essentially say this in different words:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;… since both speeds need to be relative to the same reference (the ground)...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So, if all winds disappear (i.e., wind speed = 0 m/s) then all the air is moving with the rotating frame &lt;em&gt;by definition&lt;/em&gt;.  There’s no meteorology or fluid dynamics invoked here, this just falls out from our chosen coordinate system and definition of “wind”, so it would be the same at 2 m or 25 km altitude.&lt;/p&gt;&#xA;&lt;p&gt;NB Your definition of air speed changes from &amp;quot;minus&amp;quot; in the first para to &amp;quot;plus&amp;quot; in the last para; I've assumed that this was a typo.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2021-05-25T12:09:07.723" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21309" PostTypeId="6" CreationDate="2021-05-25T16:28:53.727" Score="0" Body="&lt;h1&gt;farrenthorpe is an air quality scientist that has been an active member of Earth Science StackExchange for 7 years. farrenthorpe appreciates this online community as a great place to share knowledge with others and explore interesting scientific concepts in a cooperative Q/A format.&lt;/h1&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2021-05-25T16:28:53.727" LastActivityDate="2021-05-25T16:28:53.727" CommentCount="0" CommunityOwnedDate="2021-05-25T16:28:53.727" ContentLicense="CC BY-SA 4.0" />
  <row Id="21310" PostTypeId="2" ParentId="21301" CreationDate="2021-05-25T23:49:27.180" Score="1" Body="&lt;p&gt;When the Earth first formed, it had a rotational speed of about 12 hours. The Moon has been slowly stealing rotational speed over that time.  &lt;a href=&quot;https://courses.lumenlearning.com/boundless-physics/chapter/rotational-kinetic-energy/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This site&lt;/a&gt; estimates Earth's kinetic energy from rotation at &lt;span class=&quot;math-container&quot;&gt;$2.138×10^{29} J$&lt;/span&gt;, and since this varies with the square of rotation speed, the energy was about &lt;span class=&quot;math-container&quot;&gt;$8.5×10^{29} J$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_energy&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia article on solar energy&lt;/a&gt; says&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The total solar energy absorbed by Earth's atmosphere, oceans and land masses is approximately 3,850,000 exajoules (EJ) per year.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is &lt;span class=&quot;math-container&quot;&gt;$3.8×10^{24} J$&lt;/span&gt; per year. Over 4.5 billion years, this would aggregate to about &lt;span class=&quot;math-container&quot;&gt;$10^{34} J$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Now, I'm going to have to be handwavey here. The Sun's production of energy, as well as the Earth's ability to capture that energy, have varied a lot over time.  But this isn't enough to overcome 4 orders of magnitude -- by the beginning of the Phanerozoic, about 600 million years ago, the Sun's brightness was 97% of its current value.&lt;/p&gt;&#xA;&lt;p&gt;The aggregate amount of solar energy received during the Precambrian (assuming 25% luminosity at the beginning) -&#xA;&lt;span class=&quot;math-container&quot;&gt;$$3.8×10^{24} J×4×10^9×.62 = 9.4×10^{29} J$$&lt;/span&gt;&#xA;already matches the initial kinetic energy, but the amount received during the Phanerozoic&#xA;&lt;span class=&quot;math-container&quot;&gt;$$3.8×10^{24} J×6×10^8×.98 = 2.2×10^{33} J$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;is at least 3 orders of magnitude greater.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="2470" LastEditDate="2021-05-26T05:31:20.863" LastActivityDate="2021-05-26T05:31:20.863" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21312" PostTypeId="2" ParentId="21297" CreationDate="2021-05-26T10:01:11.530" Score="3" Body="&lt;p&gt;Earth's rotation is an important factor in contributing to the generation of the field, and helping to stabilise the form of it. The rotation influences the flow of compositionally convecting material deep within the outer core, forming cylindrical rolls that align along the rotation axis (a Coriolis effect).&lt;/p&gt;&#xA;&lt;p&gt;While Earth's field polarity may reverse occasionally, it is to a good approximation (and we believe predominantly has always been) a &lt;em&gt;roughly&lt;/em&gt; centred dipole, aligned &lt;em&gt;roughly&lt;/em&gt; with the rotation axis of the Earth because of the influence of Earth's rotation.&lt;/p&gt;&#xA;&lt;p&gt;For Uranus and Neptune, this is not the case. The centre of their dipoles are significantly offset from their centres of mass, the axes of the dipoles are significantly offset from the rotation axes.&lt;/p&gt;&#xA;&lt;p&gt;For both Uranus and Neptune, magnetic field generation is believed to occur in flowing material much closer to the planets' surfaces (due to the very different composition of ice giants versus the terrestrial Earth). With flow constrained in a relatively thin layer near the surface, planet rotation does not have a strong influence on the form of the convective motion, so the field that results is not particularly tied to how the planet rotates.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/nature02376&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; gives a good idea of how the geometry of the convecting flow region can lead to Earth-like or Neptune/Uranus-like magnetic fields.&lt;/p&gt;&#xA;" OwnerUserId="14123" LastEditorUserId="14123" LastEditDate="2021-05-26T21:08:30.660" LastActivityDate="2021-05-26T21:08:30.660" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21313" PostTypeId="1" AcceptedAnswerId="21336" CreationDate="2021-05-26T13:39:34.747" Score="4" ViewCount="308" Body="&lt;p&gt;So I was reading &lt;a href=&quot;https://www.rasch.org/rn8.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; that Mohs scale is not transitive and therefore could not overcome the comparative phase in order to be turned into a measurement procedure.&#xA;As it is written in the webpage, &amp;quot;Mohs assumed that his relation of &amp;quot;scratches&amp;quot; was transitive and asymmetrical(...). This has been shown to be false. Some minerals (...) cannot scratch each other, and yet have different powers of scratching a third mineral&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;Now I've looked at the references given in the article but couldn't find which minerals these were and a Google search yielded no information either.&lt;/p&gt;&#xA;&lt;p&gt;So my question is what are these minerals. A reference would also be greatly appreciated.&#xA;Thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="22613" LastEditorUserId="543" LastEditDate="2021-06-02T04:02:44.427" LastActivityDate="2021-06-03T19:21:03.067" Title="Are there minerals that can't scratch each other but have different hardness on Mohs scale?" Tags="|minerals|reference-request|scale|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21314" PostTypeId="1" CreationDate="2021-05-26T21:54:52.543" Score="6" ViewCount="426" Body="&lt;p&gt;Stevens Canyon Road in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Santa_Cruz_Mountains&quot; rel=&quot;nofollow noreferrer&quot;&gt;Santa Cruz Mountains&lt;/a&gt; (near Cupertino, California) passes right next to a large rock formation that, to my untrained eye, reminds me of the inside of a limestone cave. Here's some photos I snapped from when I was there:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/LsJpW.jpg&quot; alt=&quot;Top of the formation&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/uPhv5.jpg&quot; alt=&quot;The full formation&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/aBSsp.jpg&quot; alt=&quot;Top of the rock formation&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Wb3G4.jpg&quot; alt=&quot;Toward the base&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is right off the road; you can see other pictures &lt;a href=&quot;https://www.google.com/maps/@37.2727724,-122.0819249,3a,62.3y,155.89h,101.39t/data=!3m6!1e1!3m4!1sFMVkgGLAIFl9VZQ6aAHHCQ!2e0!7i16384!8i8192&quot; rel=&quot;nofollow noreferrer&quot;&gt;here on Google Maps&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The rock surface usually has water dripping over it, even in the summer when nearby creeks are otherwise dry, and it's covered in rippled ridges that remind me of the inside of the few limestone caves I've visited. This spot is right at a bend in the road and has no markings indicating what it is.&lt;/p&gt;&#xA;&lt;p&gt;My current guess - based on absolutely no expert knowledge at all - is that there's a spring at the top of the rock that's slowly dripping over the surface and slowly depositing calcium carbonate when it lands. The mountains here have a bunch of old limestone kilns (and an active cement plant, and at least one active quarry), so it seems at least somewhat plausible that rainwater is dissolving the minerals and depositing them here.&lt;/p&gt;&#xA;&lt;p&gt;Any guesses as to what, geologically, is going on here? Is there a name for this sort of formation?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Update&lt;/strong&gt;: Based on the comments that this looks like travertine, I climbed up to the top of the formation. I found a small cave carved into a rock just above it that had a steady drip of water coming down. The water was cold and clearly had a bunch of red minerals dissolved in it. (Sorry about the quality - it was getting dark)&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/Yxefl.jpg&quot; alt=&quot;A cave!&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;There was a clear path the water from there was taking that produced the drip over the surface:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/g65F7.jpg&quot; alt=&quot;The path the water takes&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;And finally, I noticed some largish rocks pushed off to the side of the road. They look like this:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/2fhgh.jpg&quot; alt=&quot;Rocks near the side&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;I noticed that the rocks near the water path up top look a lot like these, and these look a lot like random pictures of travertine that I've been Googling for.&lt;/p&gt;&#xA;&lt;p&gt;So based on this, I'm going to make the educated guess that I'm looking at travertine that's deposited on the surface of the rock. I don't think there are any nearby hot springs, but maybe this is simply water flowing through the limestone in the rock above, dissolving the minerals, and slowly depositing them on the surface?&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;&lt;em&gt;I see that questions of the form &amp;quot;identify this rock&amp;quot; are off-topic here, and I'm not sure if this counts. If so, let me know where else I should ask this.&lt;/em&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="22617" LastEditorUserId="22617" LastEditDate="2021-05-28T03:44:47.767" LastActivityDate="2021-05-28T03:44:47.767" Title="What is this geological formation in the Santa Cruz mountains that looks like a cave interior?" Tags="|geology|identification-request|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21315" PostTypeId="2" ParentId="21213" CreationDate="2021-05-27T17:51:40.943" Score="1" Body="&lt;p&gt;Wow, @John came with a simple answer.&lt;/p&gt;&#xA;&lt;p&gt;Our goal is to find&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{dT}{dP}=\frac{dT}{dz}\cdot\frac{dz}{dP}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;By the equation for pressure lapse:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$P=P_0\cdot e^{-\frac{z}{H}}$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$H=8 km=8000 m$&lt;/span&gt; (scale height) and &lt;span class=&quot;math-container&quot;&gt;$z$&lt;/span&gt; is the height above the surface.&lt;/p&gt;&#xA;&lt;p&gt;We differentiate it once, to get:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{dP}{dz}=\frac{P_0}{H}e^{-\frac{z}{H}}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The inverse value is&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{dz}{dP}=\frac{H}{P_0\cdot e^{-\frac{z}{H}}}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;And what is &lt;span class=&quot;math-container&quot;&gt;$\frac{dT}{dz}$&lt;/span&gt;? It is simply the lapse rate &lt;span class=&quot;math-container&quot;&gt;$\gamma$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Using that we restate the above:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{dT}{dP}=\frac{dT}{dz}\cdot\frac{dz}{dP}=\frac{\gamma H}{P_0\cdot e^{-\frac{z}{H}}}$$&lt;/span&gt;&#xA;But not we have that misterious &lt;span class=&quot;math-container&quot;&gt;$z$&lt;/span&gt; variable which we don't want. So,&#xA;&lt;span class=&quot;math-container&quot;&gt;$$P=P_0 e^{-\frac{z}{H}}$$&lt;/span&gt;&#xA;and&#xA;&lt;span class=&quot;math-container&quot;&gt;$$z=-H\ln\frac{P}{P_0}$$&lt;/span&gt;&#xA;We insert that in the &lt;span class=&quot;math-container&quot;&gt;$\frac{dT}{dP}$&lt;/span&gt; equation and we get&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{dT}{dP}=\frac{\gamma H}{P}$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$H=8000\rm\,m$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\gamma=6.5\rm\,\frac{K}{km}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$P=100\rm\,kPa$&lt;/span&gt;. So,&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{dT}{dP}=0.052\rm\,\frac{K}{hPa}$$&lt;/span&gt;&#xA;And that is (I believe) close enough.&lt;/p&gt;&#xA;" OwnerUserId="19122" LastEditorUserId="19122" LastEditDate="2021-08-08T21:41:16.910" LastActivityDate="2021-08-08T21:41:16.910" CommentCount="18" ContentLicense="CC BY-SA 4.0" />
  <row Id="21316" PostTypeId="1" CreationDate="2021-05-27T19:03:01.807" Score="4" ViewCount="230" Body="&lt;p&gt;A week ago, I have seen something that I have never seen before, Nah it's not a flying dragon, but clouds that were flowing so near my roof (about 5-6 meters above my roof). These are the pictures, I have taken&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mKy01.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mKy01.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Some of the clouds were passing just above the tree. I just want to know if this is a natural scene that occurs very often. What's the reason for clouds to flow so close to the surface?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Edit: My current location is 25 degrees N and 80 degrees E. it's better to call fog but they weren't stationary they were flowing quite fast from east-north to south-west. I'm attaching a couple of pictures. In the picture, the clouds are passing through that tower. Few more things to add, I'm living in the middle of the city, not in the mountains where this scenery might be seen very often. What I want is an explanation of these clouds? How they are flowing so near?&lt;/p&gt;&#xA;" OwnerUserId="22625" LastEditorUserId="22625" LastEditDate="2021-06-06T09:51:49.087" LastActivityDate="2022-07-01T12:08:15.957" Title="Is it natural for clouds to flow near the surface?" Tags="|atmosphere|clouds|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21317" PostTypeId="2" ParentId="21314" CreationDate="2021-05-28T00:45:16.970" Score="3" Body="&lt;p&gt;Well given that travertine springs trail is right next door, in castle rocks state park I am going to guess travertine. Which is a calcium carbonate mineral deposited from geothermal springs, hot ground water brings up the dissolved travertine which is deposited as the hot water evaporates, but can also slowly be dissolved and redeposited by rain. Thy can form very quickly, on the span of years or decades. There are many travertine geothermal springs in the area. If you want more information try this link for a start.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Travertine_Hot_Springs&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Travertine_Hot_Springs&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2021-05-28T00:45:16.970" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21318" PostTypeId="1" CreationDate="2021-05-28T12:47:01.080" Score="1" ViewCount="101" Body="&lt;p&gt;I live in a coastal city myself and I know there are many measures taken to prevent harm for city buildings from sea waters. I'm not aware of all of them and I wonder if modern cities actually have a plan for constantly growing sea level? How long can dams hold the water? Probably groundwater is also a problem (I think sea level may affect amount of groundwater as well) and it slowly erodes everything underneath. Do modern buildings have any kind of protection from this? Were old buildings designed with this problem in mind? How likely is it that investment in real estate in these cities may turn into dust in not-that-distant future (~40 years)&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit&lt;/strong&gt;: as it was noted in the comments section, this situation will vary between cities and the question needs to be narrowed down to a single location. I live in &lt;strong&gt;St. Petersburg (Russia)&lt;/strong&gt;, so I'd happy to see analysis for this exact place. Thank you&lt;/p&gt;&#xA;" OwnerUserId="22627" LastEditorUserId="22627" LastEditDate="2021-05-29T09:20:56.643" LastActivityDate="2021-05-29T19:22:04.143" Title="How likely is it for coastal cities to survive next 40 years?" Tags="|climate-change|groundwater|coastal|" AnswerCount="1" CommentCount="3" ClosedDate="2021-05-29T14:09:49.883" ContentLicense="CC BY-SA 4.0" />
  <row Id="21319" PostTypeId="2" ParentId="21318" CreationDate="2021-05-29T03:21:16.963" Score="2" Body="&lt;p&gt;I also live on the coast and have been concerned about what to expect with regard to sea level rise in the near future. The following graph illustrates the observed rise in sea level over the last 30 years:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/HjQ6h.jpg&quot; alt=&quot;Satellite Sea Level Observations&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;As you can see from the image, satellite data indicates a linear increase in sea level rise of 3.3 mm per year for the last 30 years. If this trend continues for the next 40 years, we will see an increase in sea level of 133 mm. The real question is whether or not the linear trend will continue or will it accelerate as a result of climate change?&lt;/p&gt;&#xA;&lt;p&gt;One possible way to look at this is to compare what temperature has done over roughly the same time period to see if there is any indication that temperature change is accelerating. The following image shows three sets of data with regard to temperature:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/p4n26.jpg&quot; alt=&quot;Observed and Modeled Temperature Change&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;The data in this image represents observed temperature changes from balloons and satellites and temperature predictions from computer models. The interesting aspect of this image is the balloon and satellite observations track very close to each other while the model predictions of temperature change are roughly 3 times greater than the observations. Another interesting point is that while the temperature is trending upward for the overall duration, there are multiple periods where the temperature is getting cooler.&lt;/p&gt;&#xA;&lt;p&gt;There is no obvious sign of acceleration in the observed data, but the current climate orthodoxy would indicate otherwise as indicated by the climate models and as a result of increased CO2 in the atmosphere. So the next logical step is to see what the CO2 levels have done over roughly the same period of time.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/jLAQl.png&quot; alt=&quot;Atmospheric CO2&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;For the last 30 years the CO2 has increased linearly at about 2 parts per million (PPM) per year.&lt;/p&gt;&#xA;&lt;p&gt;Just looking at the data, it would appear the 133 mm increase in the next 40 years would be a good conclusion, but again the current climate orthodoxy disagrees because it is believed small temperature increases resulting from increased CO2 is amplified by the positive feedback caused by the additional water vapor in the atmosphere. Water vapor is the most powerful of all greenhouse gases according to the IPCC.&lt;/p&gt;&#xA;&lt;p&gt;The counter argument to the positive feedback hypothesis is the negative feedback provided by increased cirrus cloud cover when temperatures rise. There is also the issue of the diminishing global temperature effect of CO2 as described by the five studies in the following image:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/4OEV4.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;Although the numbers are different in each of the 5 studies, they all conclude the heat retention of CO2 decreases logarithmically as the concentration increases. Using the question's time period of 40 years, the CO2 will have increased by 80 PPM to approximately 490 PPM which falls within the first level of the above chart. Using the numbers from the last three columns, the increase in temperature from CO2 alone would range from  0.2 to 0.466 degrees centigrade.&lt;/p&gt;&#xA;&lt;p&gt;One interesting conclusion from this chart is these 5 studies do not agree in the magnitude of the change which would indicate the science is not settled. Another point to be made is while CO2 concentrations increased constantly, temperatures fluctuated up and down over the same time period which indicates there are other factors in play besides CO2. These differences along with the lack of understanding of the effect the negative feedback of clouds are possible explanations of why the computer models fail to accurately mimic the actual temperature observations.&lt;/p&gt;&#xA;&lt;p&gt;Since the computer models represent the gold standard upon which future temperature predictions are being made and coupled with the fact their predictions to date have been so wrong, it is reasonable to conclude the 133 mm rise is sea level is likely to be an accurate outcome over the next 40 years. If that is the case, then the action to be taken by various coastal cities would depend upon their specific circumstances. As for me, I do not intend to sell my coastal property based on the existing evidence.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Update&lt;/strong&gt;:&#xA;The lowest parts of St. Petersburg, Russia are about 4 m above sea level. If my estimate of 133 mm sea level rise over the next 40 years is correct, then St. Petersburg will not be much worse off than they already are. I would assume the portions of the city that are that low are already having flooding issues during storms or even during high tides.&lt;/p&gt;&#xA;" OwnerUserId="22622" LastEditorUserId="22622" LastEditDate="2021-05-29T19:22:04.143" LastActivityDate="2021-05-29T19:22:04.143" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21320" PostTypeId="2" ParentId="21316" CreationDate="2021-05-29T16:53:24.197" Score="1" Body="&lt;p&gt;I believe it had been raining before. The water had gone to the soil, but the moment you took that picture, it was already evaporating. The air was filling with such water coming from the soil, but air can hold only a limited quantity of gas water, so no more water could be in the form of gas (at so called &amp;quot;point of saturation&amp;quot;). Thus, it changed its state of matter from gas to liquid. But as we all now, liquid water can be seen (the &amp;quot;gas&amp;quot; above the boiling water that we can see is actually liquid water that rapidly cools down). Also, clouds are just such liquid water caught in the air, thus a cloud formed.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fhUE5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fhUE5.png&quot; alt=&quot;Diagram of process&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The other near surface clouds can also form near the sea, with orographic clouds, descending of cloud, or on a front.&lt;/p&gt;&#xA;" OwnerUserId="19122" LastEditorUserId="19122" LastEditDate="2021-06-05T21:52:28.147" LastActivityDate="2021-06-05T21:52:28.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21321" PostTypeId="2" ParentId="7627" CreationDate="2021-05-29T19:51:59.767" Score="-3" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Why don't they do it again?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Plant life on earth has already begun to adapt to increases in CO2.&lt;/p&gt;&#xA;&lt;p&gt;The following fragment of a transcription is from a talk given by Dr. William Happer of Princeton University on February 19, 2021 to the Hillsdale College National Leadership Seminar in Phoenix, Arizona.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/NOOHP.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Geophysical Research Letters Volume 40, Issue 12 p. 3031-3035&#xA;Regular Article Impact of CO2 fertilization on maximum foliage cover across the globe's warm, arid environments&#xA;Randall J. Donohue,Michael L. Roderick,Tim R. McVicar,Graham D. Farquhar&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is the greening of the Earth measured from satellites. This picture shows areas of the Earth that are getting greener over the 20-year period. What you notice is that everywhere, especially in arid areas of Sahel (you can see that just south of the Sahara) it is greening dramatically. The western United States is greening, western Australia is greening, western India is greening. This is almost certainly due to CO2, and the reason this happens is that CO2 allows plants to grow where 50 years ago it was too dry. Plants are now needing less water to grow than they did 50 or 100 years before.&lt;/p&gt;&#xA;&lt;p&gt;Let me show you another example of what more CO2 does in terms of making plants grow better.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/4s28l.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In June 1967, Dr. Idso began his 35-year career at the U.S. Water Conservation Laboratory in Phoenix, Arizona, where he worked as a research physicist in its Environmental and Plant Dynamics Research Unit within the purview of the Agriculture Research Service’s National Program for Global Change, with responsibilities to determine the nature and degree of potential global change, to assess the likely impacts of global change on natural and agricultural ecosystems, and to develop strategies for either preventing or adapting to the potential consequences of global change, the scope of which effort was extremely broad, encompassing interrelated physical, chemical, biological, and meteorological processes, with the overall goals of minimizing water losses in agriculture, improving crop water use efficiency, and increasing the global production of food and fiber. &lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is a picture of Dr. Sherwood Idso, and it was actually an experiment done here in Phoenix back in the 1980s. This pine tree, I believe, is a Mediterranean variety, the Eldarica pine. On the left is a pine tree growing in the current CO2 level at that time, which was about 380 parts per million, and on the right are pine trees growing in higher and higher CO2 concentrations. You can see that the more CO2 the pine trees have available, the faster they grow. You can do this with almost any plant. Corn, wheat, cotton—they all grow better with more CO2. This is the so-called pollutant that you hear about in connection with the climate “emergency.”&lt;/p&gt;&#xA;&lt;p&gt;So, let me explain the basics of why that works.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/GrSMA.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Cheng, L., Zhang, L., Wang, YP. et al. Recent increases in terrestrial carbon uptake at little cost to the water cycle. Nat Commun 8, 110 (2017). &lt;a href=&quot;https://doi.org/10.1038/s41467-017-00114-5&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1038/s41467-017-00114-5&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Take a low-power magnifying glass and you will see the leaf is full of little holes or “stomata.” The little holes are to let carbon dioxide diffuse from the air into the moist interior of the leaf, where the leaf, using the special enzyme called rubisco, (one of the most ancient enzymes in the world and the most abundant protein), combines CO2 with a water molecule, H2O, to make sugar. The energy to run this little chemical factory within the leaf is provided by sunlight. The problem with this is the need for holes in the leaf. Not only do CO2 molecules diffuse in from the air, but H2O molecules diffuse out through the same hole and dry out the leaf. For every CO2 molecule that diffuses into the leaf there can be a hundred water molecules that diffuse out. So, the plant has an engineering dilemma: it has to have holes in its leaf to get the CO2 that it needs to live. But those same holes desiccate it; they dry it out, and the plant needs water to live. But plants are not stupid. All over the world, they are growing leaves with fewer or smaller holes in them in response to increasing concentrations of atmospheric CO2. If there is more CO2 in the air outside, leaves do not need as many holes, and they do not leak as much water either. That is why you are seeing the greening of the earth. It is from the plants themselves taking advantage of CO2 coming back to more historically normal levels.&lt;/p&gt;&#xA;&lt;p&gt;There is a second important issue. The enzyme I mentioned, rubisco, is very ancient. It was probably invented, on the evolutionary scale, three and a half billion years ago. At that time, there was little oxygen in the air. So, rubisco was designed in a way that lets it be poisoned by oxygen. Plants today have a hard time when there is not enough CO2 in the air. When rubisco is charged with chemical energy to make sugar, but it cannot find a CO2 molecule, it grabs an oxygen molecule, O2, instead. It uses the oxygen to create hydrogen peroxide and other nasty oxidizing molecules. One reason for the antioxidants in your tea is to mitigate this problem. This mistaken use of an O2 molecule rather than a CO2 molecule is called photorespiration. Suppression of photorespiration is one reason plants grow better with more CO2. There is a special type of plant called C4 plant, which includes American corn and sugar cane, that has partially solved this problem. But as the CO2 levels increase, the old-fashioned C3 plants, without all the biochemical machinery to cope with photorespiration, out-compete C4 plants.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.independent.org/issues/article.asp?id=13458&quot; rel=&quot;nofollow noreferrer&quot;&gt;You can read the complete text of Dr. Happer's talk here&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22622" LastEditorUserId="22622" LastEditDate="2021-05-30T14:47:17.403" LastActivityDate="2021-05-30T14:47:17.403" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="21322" PostTypeId="1" CreationDate="2021-05-29T21:28:44.543" Score="3" ViewCount="116" Body="&lt;p&gt;I'm currently working on a (relatively-simple) fluid-dynamics model of the tidal resonance at the Bay of Fundy, a place which is known for his world-breaking tidal range (15 meters on average, while the historical record is 21.6 meters - at year 1869). After a lot of effort, I succeeded in calculating the &lt;span class=&quot;math-container&quot;&gt;$M2$&lt;/span&gt; periodic-component (semi-diurnal component) of the component of the horizontal tidal force along the north-east; from looking at maps of the Bay of Fundy, I gained the impression that the longitudinal axis of its body of water is directed approximately at 45 degrees north to the eastern direction, so it's in the north-east direction (which is 45 degrees to both the north and the east).&lt;/p&gt;&#xA;&lt;p&gt;In the process of calculation I took the following values for the relevant sizes:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Declination of the Moon's orbit relative to the ecliptic - &lt;span class=&quot;math-container&quot;&gt;$5$&lt;/span&gt; degrees.&lt;/li&gt;&#xA;&lt;li&gt;Declination of the Earth's axis relative to the perpendicular to the ecliptic - &lt;span class=&quot;math-container&quot;&gt;$23.5$&lt;/span&gt; degrees.&lt;/li&gt;&#xA;&lt;li&gt;Latitude of the Bay of Fundy - &lt;span class=&quot;math-container&quot;&gt;$45$&lt;/span&gt; degrees.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Taking into account only the lunar tidal force (without the solar), the result is:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$T_\text{NE}=\frac{3GM_\text{moon}R_\text{earth}}{2L^3}\cdot 0.473\cos(\frac{2\pi}{\Delta T_\text{tide}}t),$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$\Delta T_\text{tide} = 12 \text{h} 25 \text{m}$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Now, I wanted to estimate the horizontal movement of a vertical slice of water at the Bay of Fundy using the model of a forced harmonic oscillator with the northern-eastern tidal force as the forcing function. Under the assumption of negligible damping parameter, the result is supposed to be (on basis of the solution to the forced harmonic oscillator):&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\Delta x = \frac{\frac{3GM_\text{moon}R_\text{earth}}{2L^3}\cdot 0.473}{\omega^2_\text{tide}-\omega^2_\text{seiche}}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The horizontal translation of the water slice together with its depth and width at the entry to the bay determines the amount of water flowing into the bay, and together with the length of the bay enables one to get a rough approximation of the tidal range at the narrow part of the bay (where the tides reach their peak).&lt;/p&gt;&#xA;&lt;p&gt;My problem is about getting accurate data on the geometric dimensions of the bay as well as its resonance period - taking the estimate &lt;span class=&quot;math-container&quot;&gt;$\Delta T_\text{seich}= 12\text{h} 40 \text{m}$&lt;/span&gt; gives too low values for the the tidal range - it amounts to only about &lt;span class=&quot;math-container&quot;&gt;$3$&lt;/span&gt; meters! In addition, according to Wikipedia, in each tide cycle an amount of water of approximately &lt;span class=&quot;math-container&quot;&gt;$100,000,000,000\ m^3$&lt;/span&gt; flows into the bay; if we combine this with the depth of water at the entrance of the bay (&lt;span class=&quot;math-container&quot;&gt;$200\ m$&lt;/span&gt;) and the width of its mouth (&lt;span class=&quot;math-container&quot;&gt;$52\ \text{km}$&lt;/span&gt;) we can conclude that the horizontal movement of a vertical slice of water (which is twice the amplitude) is about &lt;span class=&quot;math-container&quot;&gt;$9.5\ \text{km}$&lt;/span&gt;, much more than the result of my formula. Also, the peak depth-averaged tidal current velocity at the bay (at its narrow part) is about &lt;span class=&quot;math-container&quot;&gt;$4.5\ m/s $&lt;/span&gt;, and if we compare it with &lt;span class=&quot;math-container&quot;&gt;$\Delta x \cdot \omega_{tide}$&lt;/span&gt; than it's about 50-60 times larger (and still significantly larger if we also take into account the fact that the channel becomes narrower and shallower).&lt;/p&gt;&#xA;&lt;p&gt;Therefore, as a first step  of checking this model, I'd like to get accurate data on the geometric dimensions of the Bay of Fundy:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;What is the exact length of the Bay of Fundy? I mean the length of that part of the bay with the resonant properties. I ask because there are inconsistencies between the different sources - Encyclopedia Britannica says it's 151 km long, another source states 220 km, another 290 km, and I even found a source claiming 400 km.&lt;/li&gt;&#xA;&lt;li&gt;What is the depth of water at the entrance to the bay? What is the average depth at the bay?&lt;/li&gt;&#xA;&lt;li&gt;I'm aware that this isn't an easy question to answer experimentally, but what is the resonance period (seiche period) at the bay? I'll be glad if anyone will redirect me to good sources on the resonance period.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Finally, if the problem isn't with the accuracy of the data available on web, I want to know what is the flaw in my model.&lt;/p&gt;&#xA;" OwnerUserId="17830" LastEditorUserId="2470" LastEditDate="2021-05-30T16:45:46.523" LastActivityDate="2021-05-30T16:45:46.523" Title="Questions about the validity of a certain model for tidal resonance at the Bay of Fundy" Tags="|oceanography|tides|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="21323" PostTypeId="1" AcceptedAnswerId="21324" CreationDate="2021-05-29T21:59:59.813" Score="2" ViewCount="44" Body="&lt;p&gt;I am writing a script for calculating a precipitation index using satellite imagery, and am wondering if it can be applied to an arbitrary area or if it should be constrained to a basin. My gut says that it should depend on your research question and the information you derive from the results, but it would be good to hear an expert's thoughts! To answer Earth science questions you'd probably want to isolate the basin, but for applications outside Earth science (e.g. questions about crop yields in an administrative area) I think it could be useful.&lt;/p&gt;&#xA;&lt;p&gt;P.S. I will post the application here when I'm done with it, the idea is to make this type of analysis accessible to people without this expertise.&lt;/p&gt;&#xA;" OwnerUserId="22631" LastActivityDate="2021-05-29T23:36:08.817" Title="When calculating a precipitation index, should it be constrained to a basin?" Tags="|precipitation|gis|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21324" PostTypeId="2" ParentId="21323" CreationDate="2021-05-29T23:36:08.817" Score="2" Body="&lt;p&gt;Normally you could calculate a precipitation index for any location with a long-term record.  A basin will have nearly the same index, regardless of which station location you use, so it can be appropriate to just calculate a single value for the whole basin, as you've suggested.  The project scope will determine what level of spatial variability you need, and sometimes political boundaries are good enough (e.g. counties). Applying this same idea to a satellite-derived product, you could use a simple ecoregion boundary (see &lt;a href=&quot;https://ecoregions2017.appspot.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;) to determine the spatial resolution.  You may also want to determine spatial boundaries baed on an environmental condition that can interfere with the accuracy of the satellite retrievals you are using (e.g. surface albedo or elevation).&lt;/p&gt;&#xA;&lt;p&gt;I'm intrigued by the prospect of calculating a precipitation index from satellite imagery (instead of ground stations) and wonder which instrument(s)/products you are planning to use, especially since the calculation involves a climatological component that is difficult to build without continuous records. I suppose it is possible to train your algorithm to give results consistent with ground stations, otherwise I would worry about accuracy.  Good luck!&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2021-05-29T23:36:08.817" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="21325" PostTypeId="1" CreationDate="2021-05-30T09:04:29.463" Score="1" ViewCount="74" Body="&lt;p&gt;I'm not sure whether it's the right SE for this question, so please redirect me if it's not.&lt;/p&gt;&#xA;&lt;p&gt;Are there any studies that show that heavy metals, for example from e-waste, can leak from landfills, into the groundwater, eventually into the human body and cause any harm to human health?&lt;/p&gt;&#xA;&lt;p&gt;You can easily find information about dangers that, say, mercury vapors poses for human health. There are studies that show a high concentration of toxic metals in bodily fluids of people who engage in e-waste dismantling operations in developing countries (they burn imported e-waste to obtain metals).&lt;/p&gt;&#xA;&lt;p&gt;There were experiments on animals that were exposed to mercury and then suffered from something or died. But it seems impossible to link a certain condition with heavy metals that escaped a landfill and were digested through running water. And yet, some researchers raise this issue of landfilled e-waste and heavy metals. They might say [1], &amp;quot;Heavy metals may escape landfills&amp;quot; and in another place, &amp;quot;Heavy metals may cause brain damage and neurological disorders&amp;quot;. The two may not be explicitly connected but it's implied that heavy metal-contaminated e-waste dumped in landfills is a health issue.&lt;/p&gt;&#xA;&lt;p&gt;Are there any grounds for that (given concentrations and everything)? Are those concentrations high enough for any long-term impact? And how far do those heavy metals travel through groundwater (maybe, soil filters it out at some point, idk). Please cite academic publications, if any are available.&lt;/p&gt;&#xA;&lt;p&gt;[1]: '&lt;em&gt;Electronic waste management approaches: An overview&lt;/em&gt;', Waste Management, no. 33.&lt;/p&gt;&#xA;" OwnerUserId="22632" LastEditorUserId="2470" LastEditDate="2021-05-30T09:31:25.677" LastActivityDate="2021-05-31T15:57:29.957" Title="Are there any studies that show that heavy metals escaped from landfills can cause any harm to human health?" Tags="|human-influence|pollution|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21326" PostTypeId="1" CreationDate="2021-05-30T10:29:25.263" Score="1" ViewCount="206" Body="&lt;p&gt;I am working on WRF_GHG, I would like to calculate dry and wet deposition in the dry and wet seasons for CO&lt;sub&gt;2&lt;/sub&gt; and CH&lt;sub&gt;4&lt;/sub&gt; gases. However, when I check the wrf output, I see that all the variables (DRY_DEP_FLUX and WET_DEP_FLUX) are zero in all the time steps.&lt;/p&gt;&#xA;&lt;p&gt;I've attached my namelist.input link too.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://drive.google.com/file/d/1JS6Y77EIk0XQ3BzwHXGDH2BRk9b5rwgV/view?usp=sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://drive.google.com/file/d/1JS6Y77EIk0XQ3BzwHXGDH2BRk9b5rwgV/view?usp=sharing&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;What causes my mistake?&lt;/p&gt;&#xA;&lt;p&gt;Could I possibly ask you to check it please? Do you know why I get the wrong zero values for two of those variables (DRY_DEP_FLUX and WET_DEP_FLUX)?&lt;/p&gt;&#xA;" OwnerUserId="18881" LastEditorUserId="2470" LastEditDate="2021-05-30T16:31:13.107" LastActivityDate="2021-10-28T15:01:25.120" Title="Why are all the variables ( DRY_DEP_FLUX and WET_DEP_FLUX) zero in a wrf model output in all the time steps" Tags="|meteorology|weather-forecasting|numerical-modelling|wrf|wrf-chem|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21327" PostTypeId="2" ParentId="21325" CreationDate="2021-05-31T10:43:11.477" Score="3" Body="&lt;p&gt;The assumption is that these contaminants will leach into the ground and reach a source of drinking water. Or they will enter the food chain, by accumulating in plants, eaten by herbivores, eaten by carnivores and/or humans. So the risk is ingestion of material X, with material X being able to affect humans health if its concentration is larger than Y.&lt;/p&gt;&#xA;&lt;p&gt;There are regulations in place, generally based on scientific data from previous exposure or from analog experiments on animals or on experimental evaluation about the toxicity of heavy metals. How they combine with&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;how far do those heavy metals travel through groundwater&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;At infinite distance, given infinite time. The real question is whether, when released in the environment, they are dispersed, spreading out and having concentrations deemed to be non-toxic, or if they concentrate at the bottom of the well where freshwater is drawn to be used for agricultural use or for drinking water.&lt;/p&gt;&#xA;&lt;p&gt;However, in our age of infinite memory and the computer screen being able to show more than 20 columns or 20 rows at a time, I think &lt;a href=&quot;https://www.degruyter.com/document/doi/10.1351/pac200274050793/&quot; rel=&quot;nofollow noreferrer&quot;&gt;we can agree&lt;/a&gt; on leaving the undefined, general term &amp;quot;heavy metal&amp;quot; to music and discussing the toxicity of each substance, one by one.&lt;/p&gt;&#xA;&lt;p&gt;Since you seems keen to read books, I suggest you have a look at the first 50/60 pages of &lt;a href=&quot;https://books.google.ch/books/about/Contaminant_Hydrogeology.html?id=5B1SAAAAMAAJ&amp;amp;source=kp_book_description&amp;amp;redir_esc=y&quot; rel=&quot;nofollow noreferrer&quot;&gt;this book:&lt;/a&gt;&#xA;&amp;quot;Contaminant Hydrogeology&amp;quot; by Fetter, 1999&#xA;for a quick overview of the topic.&lt;/p&gt;&#xA;" OwnerUserId="5887" LastEditorUserId="2470" LastEditDate="2021-05-31T15:57:29.957" LastActivityDate="2021-05-31T15:57:29.957" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21328" PostTypeId="1" CreationDate="2021-05-31T13:27:20.270" Score="3" ViewCount="530" Body="&lt;p&gt;When I was researching some materials (e.g. &lt;a href=&quot;https://www.scientificamerican.com/article/10-solutions-for-climate-change/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; article in Scientific American) regarding the possible ways to fight climate change, I noticed that almost all suggestions look not like the solutions to the problem, but rather the way to slow down the problem.&lt;/p&gt;&#xA;&lt;p&gt;I mean, the efficient light bulb still emits some non-zero heat, doesn't it? Moreover, judging by the following picture (&lt;a href=&quot;https://ourworldindata.org/emissions-by-sector&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&#xA;&lt;a href=&quot;https://i.stack.imgur.com/4RXN0.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4RXN0.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;it seems that there are some sources of greenhouse gases that aren't going anywhere (we theoretically may make all cars electric but greenhouse-emitting agriculture will still remain).&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;In theory, one of the possible solutions is just to reduce the total population or significantly change lifestyle, but because, firstly, this is unrealistic and secondly, this is not the subject of this forum, let's just assume that both will remain roughly the same.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Therefore, it seems like:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Even if humanity tries its best to reduce greenhouse gases and heat emissions, it will still emit some significant positive amount of them&lt;/li&gt;&#xA;&lt;li&gt;Humanity can't do anything significant to actually reduce (and not emit less) greenhouse gases in the atmosphere&lt;/li&gt;&#xA;&lt;li&gt;Therefore, slower or faster the amount of greenhouse gases will increase&lt;/li&gt;&#xA;&lt;li&gt;Therefore, slower or faster, the temperatures will rise&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;So, &lt;strong&gt;is the climate change inevitable (supposing that current population and lifestyle remains roughly the same)&lt;/strong&gt;, or am I missing something?&lt;/p&gt;&#xA;" OwnerUserId="22316" LastEditorUserId="2470" LastEditDate="2021-05-31T15:43:29.203" LastActivityDate="2021-06-01T13:34:12.580" Title="Is it possible to actually stop climate change, or the only thing we can do is to slow it down?" Tags="|climate-change|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="21329" PostTypeId="2" ParentId="21326" CreationDate="2021-05-31T14:11:11.137" Score="1" Body="&lt;p&gt;Well I can see one major reason the dry deposition is not working- the namelist variable for gas deposition (gas_drydep_opt) is turned off. I am not entirely sure how the wet deposition works, though my guess is that it only applies to aerosols, so you would need to turn on wet scavenging for non-zero values.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://ruc.noaa.gov/wrf/wrf-chem/Users_guide.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Some of the documentation&lt;/a&gt; implies that wet deposition only applies to certain chemical mechanisms and for certain chemicals. This is probably the reason you aren't getting any wet deposition.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-05-31T14:11:11.137" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21330" PostTypeId="1" CreationDate="2021-05-31T19:05:47.510" Score="7" ViewCount="142" Body="&lt;p&gt;Following recent develoments in geophysics (&lt;a href=&quot;https://science.sciencemag.org/content/344/6189/1265&quot; rel=&quot;noreferrer&quot;&gt;Schmidt et al. (2014)&lt;/a&gt;, and a &lt;a href=&quot;https://www.theguardian.com/science/2014/jun/13/earth-may-have-underground-ocean-three-times-that-on-surface&quot; rel=&quot;noreferrer&quot;&gt;popular summary&lt;/a&gt;), we now know there to be a significant reservoir of water in the mantle-transition of planet Earth, now often quoted as &amp;quot;additional 3 oceans worth of water in the mantle&amp;quot;. Here one ocean is being counted as &lt;span class=&quot;math-container&quot;&gt;$\sim 10^{23}\rm kg$&lt;/span&gt; of water.&lt;/p&gt;&#xA;&lt;p&gt;While a definitive answer to this is probably outstanding, I would be interested in knowing where this water was, prior to the onset of plate tectonics (e.g. &lt;a href=&quot;https://earthscience.stackexchange.com/questions/418/how-did-earths-plate-tectonics-start/18601#18601&quot;&gt;see this question&lt;/a&gt;) at probably &lt;span class=&quot;math-container&quot;&gt;$\sim 3\rm \,Ga$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Were the - in total - 4 oceans worth of water (ignoring loss of volatiles to space) delivered with the initially accreted solids, or did it come as a late veneer, cover the Earth first completely, before slowly diffusing into the mantle, starting tectonics and establishing re-/degassing equilibrium at 1 ocean on the surface? What geophysical data is out there to decide between those scenarios?&lt;/p&gt;&#xA;&lt;p&gt;A recent review on the topic by &lt;a href=&quot;https://progearthplanetsci.springeropen.com/track/pdf/10.1186/s40645-020-00379-3.pdf&quot; rel=&quot;noreferrer&quot;&gt;Karaki et al. (2020)&lt;/a&gt;, does not say much about the planet formation perspective on this, and the aim of my question points in the direction of deciding whether pebble accretion or planetesimal accretion would have been the main contributor for volatiles on our planet.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2021-06-11T04:37:10.797" Title="Was Earth completely covered in Oceans prior to the onset of plate tectonics?" Tags="|planetary-science|mantle|planetary-formation|" AnswerCount="1" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="21331" PostTypeId="2" ParentId="21313" CreationDate="2021-06-01T09:20:48.547" Score="3" Body="&lt;p&gt;It may be difficult to ascertain the hardness of a mineral relative to an other mineral in a Mohs streak test if one (or both) are not homogeneous. Already a small local grain of an impurity may put you off; you might remember the occasions of the sudden scratching sound of chalk on the green board.  Which is why pen-shaped &lt;a href=&quot;https://newgrind.com/how-to-use-your-mohs-hardness-pick-kit/&quot; rel=&quot;nofollow noreferrer&quot;&gt;hardness picks&lt;/a&gt; are advantageous: to use a tip made a (synthetic) alloy with reproducible hardness (except for #2 and #3 made of plastic, or copper) to aim right on your region of interest:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/34Le7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/34Le7.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(&lt;a href=&quot;https://geology.com/minerals/mohs-hardness-scale.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;credit&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;Equally, it is a question of technique (if adhering to &lt;em&gt;this&lt;/em&gt; protocol), too, as mentioned by, e.g.,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;«One must also use enough force to create the scratch (if you don't use enough force even diamond will not be able to scratch quartz - this is an area where &lt;em&gt;practice is important&lt;/em&gt;).»&lt;/p&gt;&#xA;&lt;p&gt;(credit to &lt;a href=&quot;http://www.minsocam.org/msa/collectors_corner/article/mohs.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mineralogical Society of America&lt;/a&gt;, emphasis added)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;or&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;«Don't be wimpy! This is a very common problem. Some people casually rub one specimen back and forth against another and then look for a mark. That is not how the test is done! It is done with a single, slow, determined motion, with firm pressure, with the goal of cutting a scratch.»&lt;/p&gt;&#xA;&lt;p&gt;(credit to &lt;a href=&quot;https://geology.com/minerals/mohs-hardness-scale.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;geology.com&lt;/a&gt;, compiling some potential pitfalls)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;while both a) the relative orientation of the mineral to be tested &lt;em&gt;.vs.&lt;/em&gt; a reference, and b) the origin of a mineral may yield different degrees of hardness.&lt;/p&gt;&#xA;&lt;p&gt;(Hardness by Mohs (and streak) isn't the only scale.  In materials science, there equally are hardness tests by indentation e.g., &lt;a href=&quot;https://en.wikipedia.org/wiki/Rockwell_scale&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rockwell&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Brinell_scale&quot; rel=&quot;nofollow noreferrer&quot;&gt;Brinell&lt;/a&gt;.)&lt;/p&gt;&#xA;" OwnerUserId="18990" LastActivityDate="2021-06-01T09:20:48.547" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21332" PostTypeId="2" ParentId="21328" CreationDate="2021-06-01T11:24:01.813" Score="1" Body="&lt;p&gt;Yes, it is possible to reverse climate change, at least technically, and it does not require absurd technology to do so.  (The political issues are entirely different and clearly off-topic, so I won't mention them further.)&lt;/p&gt;&#xA;&lt;p&gt;First of all something you say indicates a possible confusion: you said&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;the efficient light bulb still emits some non-zero heat, doesn't it?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;And the important thing here is that human energy production (which ends up as heat) is an absolutely negligible &lt;em&gt;direct&lt;/em&gt; cause of climate change.  It's possible to work out what it is but it's a tiny fraction of a degree.  It's also possible that in some future world it may start to be a direct problem, but it is not currently.  See &lt;a href=&quot;https://dothemath.ucsd.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tom Murphy's excellent blog (and now &lt;em&gt;free&lt;/em&gt; book!)&lt;/a&gt; for some calculations on this.&lt;/p&gt;&#xA;&lt;p&gt;Climate change is not caused by waste heat from human energy use: it's caused by processes which modulate the energy which arrives on Earth from the Sun, which is hugely greater (I did a simple-minded calculation based on &lt;a href=&quot;https://ourworldindata.org/energy-production-consumption&quot; rel=&quot;nofollow noreferrer&quot;&gt;this page&lt;/a&gt; and got a figure of about &lt;span class=&quot;math-container&quot;&gt;$11500$&lt;/span&gt; times more energy arriving at the top of the atmosphere from the Sun than human energy production).&lt;/p&gt;&#xA;&lt;p&gt;So, anthropogenic climate change is not driven by human waste heat: it's driven by gases we dump into the atmosphere which alter its characteristics in such a way that there is warming on the surface.  Mostly this means &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt;, which is a waste product of burning fossil fuels.  To reverse climate change we need to lower the concentration of &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; in the atmosphere (and other greenhouse gases but I'll just talk about &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; below).&lt;/p&gt;&#xA;&lt;p&gt;Before starting, it's important to realise that there are &lt;em&gt;natural&lt;/em&gt; processes which scavenge &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; from the atmosphere as well as ones which produce it: the concentration doesn't just endlessly increase.  Indeed the fossil fuels we are busily burning are the result of just such scavenging of &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt;: all that carbon was removed from the atmosphere by organisms over geological time and turned into coal, oil etc.  If such processes didn't exist we would simple not be here at all.&lt;/p&gt;&#xA;&lt;p&gt;So to reduce the concentration of &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; in the atmospere there are, really, two possible broad-brush approaches:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;we can reduce our emissions of &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; to a relatively small level, and wait until natural processes scavenge it from the atmosphere;&lt;/li&gt;&#xA;&lt;li&gt;or we can actively do things which scavenge it from the atmosphere ourselves.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;And we can do any combination of (1) &amp;amp; (2) of course.&lt;/p&gt;&#xA;&lt;p&gt;For (1) there are several things to say.  Firstly I don't know what the level which would eventually be reached is: there's no reason to believe it will be the same as the preindustrial level I think (and obviously the &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; level in the atmosphere is not long-term constant in any case: it just generally changes rather slowly over time compared to recent anthropogenic increase).  Secondly, this would take a long time, just because the natural scavenging processes are generally slow: there is a summary &lt;a href=&quot;http://geosci.uchicago.edu/%7Earcher/reprints/archer.2009.ann_rev_tail.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; (from a few years ago), but the timescales are hundreds of years I think.&lt;/p&gt;&#xA;&lt;p&gt;But one important thing about (1) is that 'a relatively small level' doesn't mean 'living in the 18th century': &lt;em&gt;more than half of the total anthropogenic &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; in the atmosphere has been put there since 1990&lt;/em&gt;.  Life was reasonably pleasant in 1990 (although it helped a lot if you lived in the first world).  [&lt;strong&gt;Edit&lt;/strong&gt; following a comment. The previous statement is misleading: &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; emissions need to be lower than they were in 1990 in the 1st world, and really quite a lot lower.  But they don't need to be 18th-century low, and we don't need to live 18th-century lifestyles.]&lt;/p&gt;&#xA;&lt;p&gt;To actually know what the options around (1) are you have to do hairy calculations which I'm not up to.&lt;/p&gt;&#xA;&lt;p&gt;For (2) we would need to scavenge &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; ourselves.  That doesn't have to mean building giant &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt;-scavenging machines.  For instance trees are machines which turn atmospheric &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; into, well, tree: a large tree can weigh tens of tonnes, and a great chunk of that mass is carbon, all of which came from atmospheric &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt;.  And that mass doesn't include all the leaves it has dropped over its life.  Obviously to actually understand what trees do in terms of &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; you need to look at what happens after they die as a bunch of the carbon then gets turned back into &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; as they rot, and again this involves hairy calculations (which people do).  But overall it's safe to say that trees are pretty heavily carbon-negative.&lt;/p&gt;&#xA;&lt;p&gt;So planting trees (and other green plants, but trees are pretty good I think) are one way that humans can, in fact, actively pull &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; out of the atmosphere over periods of tens of years.&lt;/p&gt;&#xA;&lt;p&gt;There are also all sorts of other approaches including the more high-tech fixes that a lot of people enthuse about.  For instance if we had unlimited very cheap power (say fusion which we'll likely have in due course, or cheap solar power which we already have) then it's easily possible to imagine a giant &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt;-o-tron machine which will pull &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; out of the atmosphere and turn it into, say, carbon and oxygen, driving the reaction backwards by pushing lots of energy into it.  This will produce a bunch of waste heat, but see above on the contribution of waste heat to climate change.&lt;/p&gt;&#xA;&lt;p&gt;There are a lot of other options here as well.  I don't want to (and can't) enumerate them all.  However I hope I have made the point that it certainly is the case that we can absolutely do things which would reduce the concentration of &lt;span class=&quot;math-container&quot;&gt;$\mathrm{CO_2}$&lt;/span&gt; in the atmosphere over periods as short as tens of years, and many of those things are not absurdly implausible.&lt;/p&gt;&#xA;" OwnerDisplayName="user18801" LastEditorDisplayName="user18801" LastEditDate="2021-06-01T13:34:12.580" LastActivityDate="2021-06-01T13:34:12.580" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21333" PostTypeId="1" AcceptedAnswerId="21334" CreationDate="2021-06-01T20:38:31.590" Score="-4" ViewCount="1654" Body="&lt;p&gt;Imagine a room of 10x10 feet in size with a 10 feet high ceiling. The air in the room consists of roughly 78 percent nitrogen and 21 percent oxygen. The windows are shut closed and the gap under the door is sealed. How much nitrogen would you need to add, in order to reduce the oxygen level to less than 5%? For the sake of simplicity lets assume that the pressure in the room should stay the same as before, and that the surplus air just escapes.&lt;/p&gt;&#xA;" OwnerUserId="22652" LastActivityDate="2021-06-02T16:07:15.453" Title="How much nitrogen would you need to replace all oxygen in a room of 1,000 cubic feet?" Tags="|oxygen|nitrogen|" AnswerCount="1" CommentCount="3" ClosedDate="2021-06-05T12:23:13.310" ContentLicense="CC BY-SA 4.0" />
  <row Id="21334" PostTypeId="2" ParentId="21333" CreationDate="2021-06-01T21:29:05.360" Score="3" Body="&lt;p&gt;Your assumption about constant pressure can't actually exist while everything is closed. I am not using this assumption here because it is more correct and a bit easier:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\pu{10 feet} = \pu{3.048 m}$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$(\pu{10 feet})^3 = \pu{28.3 m^3} = \pu{28300 L}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;We can calculate the amount of substance using ideal gas equation:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$pV = nRT$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$n = \frac{pV}{RT} = \frac{101.325\cdot 28300}{8.31\cdot 293.15}\text{ mol} = \pu{1177 mol}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;There is 78 percent nitrogen, 21 percent oxygen and 1 percent of other gases:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$n(\ce{N2}) = 0.78\cdot n = \pu{918.06 mol}$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$n(\ce{O2}) = 0.21\cdot n = \pu{247.17 mol}$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$n(\text{oth.}) = 0.01\cdot n = \pu{11.77 mol}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The amount of oxygen is constant, but we want to reach 5%. Thus, the total amount of substance after the insertion of nitrogen is:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$n'(\text{together}) = n'(\ce{N2}) + n'(\ce{O2}) + n'(\text{oth.}) = \frac{n'(\ce{O2})}{0.05} = \frac{n(\ce{O2})}{0.05} = \frac{\pu{247.17 mol}}{0.05} = \pu{4943.4 mol}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Also, &lt;span class=&quot;math-container&quot;&gt;$n'(\text{oth.}) = n(\text{oth.})$&lt;/span&gt;, thus:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$n'(\ce{N2}) = n'(\text{together}) - n'(\ce{O2}) - n'(\text{oth.}) = \pu{4943.4 mol} - \pu{247.17 mol} - \pu{11.77 mol} = \pu{4684.46  mol}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;So the solution is &lt;span class=&quot;math-container&quot;&gt;$\pu{4684 mol}$&lt;/span&gt;, but we can't imagine that easily. Mass of &lt;span class=&quot;math-container&quot;&gt;$\pu{4684 mol}$&lt;/span&gt; of nitrogen is:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$m'(\ce{N2}) = M(\ce{N2}) \cdot n'(\ce{N2}) = 2 \cdot 14.007 \cdot \pu{4684.46 g} = \pu{131.23 kg}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Also, the volume of such nitrogen at normal pressure is equal to:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$V'(\ce{N2}) = \frac{n'(\ce{N2})\cdot RT}{p} = \frac{4684.46\cdot 8.31\cdot 293.15}{101.325}\text{ L} = \pu{112600 L} = \pu{112.6 m^3}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Thus, we need to add &lt;span class=&quot;math-container&quot;&gt;$\pu{112.6 m^3}$&lt;/span&gt; of nitrogen to reach 5% concentration of oxygen. The answer seems reasonable because we need to add approximately 4 times of the original volume in order to lower the concentration 4 times.&lt;/p&gt;&#xA;" OwnerUserId="19122" LastEditorUserId="18990" LastEditDate="2021-06-02T16:07:15.453" LastActivityDate="2021-06-02T16:07:15.453" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="21336" PostTypeId="2" ParentId="21313" CreationDate="2021-06-02T05:46:01.170" Score="3" Body="&lt;p&gt;The idea discussed in the paper you reference is about transferability of Mohs ordinal scale to true hardness.  A mineral's ability to scratch is related to it's hardness, but only an indentation test measures absolute hardness (e.g. the Vickers scale). Mineral orientation relative to planar structure can change the result in a scratch test, and two minerals that can't scratch each other may actually differ in hardness. &lt;a href=&quot;https://www.thefreelibrary.com/The+sclerometer+and+the+determination+of+the+hardness+of+minerals.-a0115308712&quot; rel=&quot;nofollow noreferrer&quot;&gt;This page&lt;/a&gt; discusses scratch test problems and has a thorough narrative of the development of testing hardness of minerals.&lt;/p&gt;&#xA;&lt;p&gt;The table below (from &lt;a href=&quot;https://patents.google.com/patent/WO2013059334A1/en&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;) compares hardness scales for several minerals, some of which have the same number on the Moh's scale, but a big difference in the Vickers number.  This is an issue for Campbell in his theory of measurement, because Mohs is not an additive scale where mineral hardness goes up or down consistently.&lt;/p&gt;&#xA;&lt;p&gt;Using the table below you could postulate some issues with Mohs scale.  For example, rutile and pyrite would not scratch each other, but they would have different results when they were used to scratch chromite, since their rank is different across Mohs and Vickers.  However, I am not a geologist, so I welcome corrections to this assertion.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SdGqh.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SdGqh.png&quot; alt=&quot;mohs vs vickers&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2021-06-03T19:21:03.067" LastActivityDate="2021-06-03T19:21:03.067" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21337" PostTypeId="1" CreationDate="2021-06-02T07:20:47.647" Score="5" ViewCount="160" Body="&lt;p&gt;This is not exactly a pure Earth Science question but I'm not sure &lt;a href=&quot;https://gis.stackexchange.com/&quot;&gt;GIS SE&lt;/a&gt; is a suitable place either.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;The Google&amp;quot; suggested I watch CBS Sunday Morning's &lt;a href=&quot;https://www.youtube.com/watch?v=s6L9xben6ug&quot; rel=&quot;nofollow noreferrer&quot;&gt;The debate over the geographical center of North America&lt;/a&gt; and I complied.&lt;/p&gt;&#xA;&lt;p&gt;The video explains that &lt;strong&gt;Rugby North Dakota&lt;/strong&gt; (48.37 N, 99.99 W) was determined to be the &amp;quot;geographic center&amp;quot; of North America by &lt;strong&gt;balancing a cutout of the continent on a pin.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;This method weights each point by its vector to the center; a point twice as far will be weighted twice as much.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UdFrp.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UdFrpm.jpg&quot; alt=&quot;screenshot from CBS Sunday Morning's &amp;quot;The debate over the geographical center of North America: https://www.youtube.com/watch?v=s6L9xben6ug&quot; /&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/RCqMb.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RCqMbm.jpg&quot; alt=&quot;screenshot from CBS Sunday Morning's &amp;quot;The debate over the geographical center of North America: https://www.youtube.com/watch?v=s6L9xben6ug&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;The second determination was done in a bar by utilizing the well known &lt;strong&gt;standard string, globe and beer methodology&lt;/strong&gt;. It was found to be &lt;em&gt;inside Hanson's bar itself&lt;/em&gt; in &lt;strong&gt;Robinson North Dakota&lt;/strong&gt; (47.14 N 99.78 W).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ifl7H.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ifl7Hm.jpg&quot; alt=&quot;screenshot from CBS Sunday Morning's &amp;quot;The debate over the geographical center of North America: https://www.youtube.com/watch?v=s6L9xben6ug&quot; /&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/B8Wjm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/B8Wjmm.jpg&quot; alt=&quot;screenshot from CBS Sunday Morning's &amp;quot;The debate over the geographical center of North America: https://www.youtube.com/watch?v=s6L9xben6ug&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vU4GA.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vU4GAm.jpg&quot; alt=&quot;screenshot from CBS Sunday Morning's &amp;quot;The debate over the geographical center of North America: https://www.youtube.com/watch?v=s6L9xben6ug&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;The third determination was done using a &lt;strong&gt;personal computer and google maps&amp;gt; perimeter coordinates&lt;/strong&gt;&lt;sup&gt;2&lt;/sup&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Professor Peter Rogerson&lt;sup&gt;1&lt;/sup&gt; took latitudes and longitudes from all around the edges of North America, and plugged those coordinates into a special algorithm that he designed, to find the center.&lt;/p&gt;&#xA;&lt;p&gt;”You have to take into account that the Earth’s surface is curved, and you want to find that balance point in a proper way.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This turns out by &lt;em&gt;sheer coincidence&lt;/em&gt; to be near &lt;strong&gt;Center North Dakota&lt;/strong&gt; (47.12 N, 101.30 W)!&lt;/p&gt;&#xA;&lt;p&gt;So back to the balance point with it's vector distance from center weighting.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Bapys.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Bapysm.jpg&quot; alt=&quot;screenshot from CBS Sunday Morning's &amp;quot;The debate over the geographical center of North America: https://www.youtube.com/watch?v=s6L9xben6ug&quot; /&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/nwamo.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nwamom.jpg&quot; alt=&quot;screenshot from CBS Sunday Morning's &amp;quot;The debate over the geographical center of North America: https://www.youtube.com/watch?v=s6L9xben6ug&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;Questions:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;When finding the geographic center of a continent is balance point the accepted method?&lt;/li&gt;&#xA;&lt;li&gt;Is this mathematically equivalent to finding the centroid?&lt;/li&gt;&#xA;&lt;li&gt;&amp;quot;bonus points&amp;quot; how did Rogerson convert &lt;em&gt;a perimeter to a balance point?&lt;/em&gt; Has this been published?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt;&lt;a href=&quot;http://www.buffalo.edu/cas/geography/faculty/faculty_directory/peter-a--rogerson.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Peter A. Rogerson, Department of Geography&lt;/a&gt;, State University of New York Buffalo&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;2&lt;/sup&gt;hat tip to @EarlGray for their &lt;a href=&quot;https://earthscience.stackexchange.com/questions/21337/?noredirect=1#comment50499_21337&quot;&gt;very helpful comment&lt;/a&gt;!&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="22648" LastEditDate="2021-06-02T14:10:07.180" LastActivityDate="2023-02-17T21:27:19.137" Title="To Determine the Geographic center of a continent, is balance point the accepted method and is equivalent to finding the centroid?" Tags="|geography|terminology|continent|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21339" PostTypeId="1" CreationDate="2021-06-02T19:42:14.530" Score="4" ViewCount="66" Body="&lt;p&gt;From what I know so far, a slowdown/shutdown in the gulf stream would cause climate change to run counter to the way that it would normally progress (i.e. poles warming faster than the tropics.) Warm water would go around in circles near the tropics, rather than making its way past northern Europe to sink near Greenland, causing the heat content of the tropics to increase disproportionately more at the expense of warming in the arctic.&lt;/p&gt;&#xA;&lt;p&gt;It's easy to find material that describes how this would affect Europe. Europe would get cooler (or at least not warm as much) and would also get substantially drier. What's harder to find is information on what the effects would be on the weather systems of North America.&lt;/p&gt;&#xA;&lt;p&gt;What would the effects be on the climate of the gulf coast and eastern seaboard? Would places on the same latitude as Europe such as Newfoundland experience similar changes to the former i.e. cooler and drier?&lt;/p&gt;&#xA;&lt;p&gt;If I could hazard a guess, I might imagine sea surface temperatures going up substantially year round in the Gulf of Mexico. Bringing in strong blasts of moisture and humidity into the American southwest and  interior plains. Hurricanes would get far stronger, and the expansion of tropical koppen climates would extend further beyond the Florida peninsula.&lt;/p&gt;&#xA;&lt;p&gt;Are there any studies that look specifically into this question? What would be your educated guess as to what would happen to North America's climate?&lt;/p&gt;&#xA;" OwnerUserId="22656" LastEditorUserId="2470" LastEditDate="2021-06-03T05:11:28.133" LastActivityDate="2021-06-03T05:11:28.133" Title="What effect would a slowdown of the AMOC have in particular on North America's climate/weather?" Tags="|meteorology|climate-change|climate|oceanography|precipitation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="21341" PostTypeId="1" CreationDate="2021-06-03T09:21:06.830" Score="1" ViewCount="56" Body="&lt;p&gt;The city in which I live has a number of roads that are regularly above the legally allowed yearly average level of nitrogen dioxide permitted (40ug/m3).  One road is almost double that limit (77ug/m3) and another is 50% over (62ug/m3).  The levels have been similar for many years with only small reductions.&lt;/p&gt;&#xA;&lt;p&gt;The large number of double decker buses are a major cause of this pollution but we have been told they will not be going electric anytime soon.  The large number of cars is another.  The number of heating units in this densely populated city is another.  The council has not provided any reasonable solution for this and has made the situation worse in some locations by building housing in illegally polluted areas in a way that will inhibit pollution dispersal.&lt;/p&gt;&#xA;&lt;p&gt;This is a long standing issue and it seems no realistic solutions have been mentioned.  The poor air quality is leading to poor health and early death.&lt;/p&gt;&#xA;&lt;p&gt;I want my council to take the situation seriously.  I am considering an official question to my council and am about to ask them to declare the city a 'human made environmental disaster'.  Would this declaration be appropriate?  Is it an exageration of the situation?&lt;/p&gt;&#xA;" OwnerUserId="18003" LastActivityDate="2021-06-03T17:46:09.060" Title="Could the phrase 'human made environmental disaster' be applied to illegal and deadly city wide pollution?" Tags="|air-pollution|pollution|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="21342" PostTypeId="2" ParentId="21341" CreationDate="2021-06-03T17:46:09.060" Score="3" Body="&lt;p&gt;I think there is a bit to unpack in your question, starting with the definition of terms. Just starting off with the title question, yes - examples include &lt;a href=&quot;https://en.wikipedia.org/wiki/1948_Donora_smog&quot; rel=&quot;nofollow noreferrer&quot;&gt;the 1948 Donora Smog event&lt;/a&gt;, and the &lt;a href=&quot;https://www.theguardian.com/world/2016/nov/06/delhi-air-pollution-closes-schools-for-three-days&quot; rel=&quot;nofollow noreferrer&quot;&gt;2006 Delhi Smog event.&lt;/a&gt; The use of the word disaster is usually reserved for catastrophes, not exceedances.&lt;/p&gt;&#xA;&lt;p&gt;There are a couple of problems with just claiming that something is an environmental disaster. For one, there is the political problem. Claiming that the city is an environmental disaster could be a concession of defeat. This also could ward off prospective inhabitants or cause the diversion of other funds. The double decker buses are also public transit, and may produce less pollution as compared to individual cars.&lt;/p&gt;&#xA;&lt;p&gt;There is also a siting issue. Usually those regulations are applied to sites that are representative of the area at large. The distance from the source is an important consideration when looking at measurements of atmospheric chemicals. Individual sites may exceed the limit, but does the average of the sites exceed the limit? There is also a question of by what extent is the limit exceeded or why is the limit exceeded? Is it exceeded for an hourly limit, 24 hour averaged limit, or an 8-hour average limit? Sometimes, it is not unheard of to exceed the limit, but the people who set these limits set them more as goals- goals that keep getting pushed back as more places achieve them. When was the limit last changed?&lt;/p&gt;&#xA;&lt;p&gt;Here are a few questions that you might want to be prepared to answer if you bring this issue to council, based on how this question is phrased:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;How many people have died as a result of inaction? What evidence do you have of this increase in premature death? This is probably the biggest gauge for yourself whether or not this issue is exaggerated.&lt;/li&gt;&#xA;&lt;li&gt;Why does your governmental environmental agency seem less concerned than you are? Presumably, your governmental environmental agency's job is to monitor and reduce pollution. If your city council isn't being pushed by the governmental agency, perhaps there is more at work than what is being let on. Perhaps there is corruption, or perhaps the council's hands are tied.&lt;/li&gt;&#xA;&lt;li&gt;What reasonable solutions do you propose? And what public funds should be diverted to pay for those solutions? It is good to be idealistic, but every thing comes with a cost. Are people willing to pay that cost?&lt;/li&gt;&#xA;&lt;li&gt;Have you consulted an engineer to identify alternative structures that could provide for a similar number of housing units for a similar price? Usually the places built in areas with high pollution are more affordable, and the shape of the structures are meant to accommodate more people. Are you willing to be accused of promoting gentrification?&lt;/li&gt;&#xA;&lt;li&gt;How much does the pollution vary due to factors outside of the control of the city? Is the pollution being reported consistently, or is it heavily dependent on anomalous traffic patterns (holidays, sporting events) and weather?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-06-03T17:46:09.060" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="21343" PostTypeId="2" ParentId="4518" CreationDate="2021-06-04T00:08:44.323" Score="1" Body="&lt;p&gt;An epidemic-type aftershock sequence (ETAS) model is a marked point process model.&lt;/p&gt;&#xA;&lt;p&gt;Typically, a temporal model has the form (Ogata, 1988):&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ \lambda^*(t) = \mu + \sum k10^{\alpha(M_i-M_c)} (t_i+c)^{-p} $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where &lt;span class=&quot;math-container&quot;&gt;$\lambda^*(t)$&lt;/span&gt; is a conditional intensity function. If you are using no marks (e.g. earthquake magnitudes) you may be dealing with a Hawkse process.&lt;/p&gt;&#xA;&lt;p&gt;Then the likelihood of an event can be written as:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$f(t|\mathcal{H}_{t_n}) = \lambda^*(t)e^{-\int^t_{t_n}{\lambda^*(s) ds}} $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is in fact what is optimized in the maximum likelihood estimation, typically using the log likelihood of all the events:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ logL = \sum log\lambda^*(t_i) -\int_0^T \lambda^*(s)ds $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;If I understand the question correctly. The probabibily that an event does not occur in between the time of an event &lt;span class=&quot;math-container&quot;&gt;$t_i$&lt;/span&gt; and some time &lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt; can be written as &lt;span class=&quot;math-container&quot;&gt;$1-F(t)$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$F(t)$&lt;/span&gt; is the cumulative distribution of the event likelihood such that:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$1-F(t) = \exp\left(-\int_{t_n}^t \lambda^*(s)ds\right)$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;I do not know the exact form of the ETAS model you are using, but it should be reasonably straightforward to implement from here on end.&lt;/p&gt;&#xA;&lt;p&gt;Refer to this excellent note set for more:&#xA;&lt;a href=&quot;https://arxiv.org/pdf/1806.00221.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://arxiv.org/pdf/1806.00221.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6245" LastActivityDate="2021-06-04T00:08:44.323" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22343" PostTypeId="1" CreationDate="2021-06-04T05:05:32.683" Score="12" ViewCount="652" Body="&lt;p&gt;I’m a sailing captain in training and my community members asked about confidence in wind predictions. They were unhappy with the large variation between different wind predictions. The speed and directions from different sources were at times in agreement, but at other times they were completely opposite and with a large delta.&lt;/p&gt;&#xA;&lt;p&gt;I would like to explain that some of the confidence levels of individual wind speed predictions may be very low. Therefore it should be taken in consideration when comparing those wind predictions to other low confidence wind predictions and that both may be entirely wrong. I could not locate any documentation that showed were confidence levels or each individual wind prediction was being calculated or conveyed. Did I miss something?&lt;/p&gt;&#xA;&lt;p&gt;Wouldn’t it make sense to say something like: we think the wind at this latitude/longitude will be 8.5 knots in the N direction and we are 95% confident of this prediction? That confidence part seems to be missing. Or is it calculated and just not displayed to the end user? It could save a sailor’s life!&lt;/p&gt;&#xA;" OwnerUserId="22663" LastEditorUserId="502" LastEditDate="2021-06-07T10:42:16.550" LastActivityDate="2021-06-09T04:54:15.447" Title="Do wind predictions have confidence scores?" Tags="|meteorology|weather-forecasting|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22344" PostTypeId="1" CreationDate="2021-06-04T10:57:31.393" Score="3" ViewCount="38" Body="&lt;p&gt;As the title suggests, I am looking for the most reliable database(s) of parent-or bedrock chemistry, e.g. the concentration of nitrogen, phosphorus and some other metals (basically plant nutrients). Since I am not a researcher in this area, it is very hard for me to determine, I would really appreciate if someone can point me to a specific source or direction.&lt;/p&gt;&#xA;" OwnerUserId="3241" LastEditorUserId="2470" LastEditDate="2021-06-04T11:12:04.800" LastActivityDate="2021-06-09T11:08:54.950" Title="Spatially-explicit global database of parent rock chemistry?" Tags="|geochemistry|bedrock|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22345" PostTypeId="1" CreationDate="2021-06-04T14:19:29.483" Score="1" ViewCount="128" Body="&lt;p&gt;From the composition of soil air, we know that oxygen is much less than that of atmospheric air. On the other hand, carbon dioxide is higher in soil. However, nitrogen gas is very much similar in both cases. According to the chapter &lt;em&gt;Aeration&lt;/em&gt; in the book &lt;em&gt;Encyclopedia of Soils in the Environment (2005)&lt;/em&gt;,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Since nitrogen gas (N&lt;sub&gt;2&lt;/sub&gt;) is more abundant than other gases in the atmosphere (approx. 78%) and there are generally no sources or sinks for N&lt;sub&gt;2&lt;/sub&gt; in the soil (except N&lt;sub&gt;2&lt;/sub&gt; absorbed during nitrogen fixation or produced during denitrification), the concentration of N&lt;sub&gt;2&lt;/sub&gt; in the soil air will be similar to that in the atmosphere, varying only slightly depending on the production and consumption of other soil gases.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Is there a better explanation? Is this the only reason for the similarity? An explanation with references will be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="22648" LastEditorUserId="6467" LastEditDate="2021-06-04T22:38:30.510" LastActivityDate="2021-06-04T22:38:30.510" Title="Why is the concentration of nitrogen gas almost equal in soil air and the atmosphere?" Tags="|soil-science|nitrogen|air|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22346" PostTypeId="2" ParentId="22343" CreationDate="2021-06-04T16:37:04.197" Score="10" Body="&lt;p&gt;We've grown accustomed to seeing percentages for probability of precipitation.  Why don't they do this for wind?&lt;/p&gt;&#xA;&lt;p&gt;No single model simulation has confidence/uncertainty associated with it.  Confidence is determined after many model simulations are performed with different model configurations, known as an &amp;quot;ensemble&amp;quot;. The percentage reported is a probability of rain occurring, which is a binary event (yes vs no) &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4511/how-to-interpret-hourly-precipitation-forecast&quot;&gt;averaged across all ensemble members&lt;/a&gt;. The hourly percentage probability is not factoring in the amount of rain, it just has to be higher than 0.01&amp;quot; in the model.  Precipitation is cumulative and not really directional in nature, so calculating probability of a yes/no event is actually meaningful.  Wind, in contrast, is a vector that really isn't thought of as a binary event.  If the forecast said there was an 80% chance of wind over 1 m/s, that wouldn't help anyone.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Your example:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;8.5 knots in the N direction and we are 95% confident of this prediction?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;would really look more like:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;8.5 knots with standard deviation of 2 knots from NNW with standard deviation of 30 degrees&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Wind direction vs wind speed:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Predicting precise wind direction at the surface is extremely difficult, while upper atmosphere winds are less complex. Also consider that a highly confident wind direction prediction could be very inaccurate.  The &amp;quot;confidence&amp;quot; of wind direction can be calculated but the ensemble average of hourly wind direction at the surface is often of low accuracy.  Thus model &amp;quot;confidence&amp;quot; of wind direction probably isn't of much value to the public.  Sometimes surface wind direction predictions can be relatively confident and accurate due to terrain that channels flow in the same direction consistently.  However, at sea you have no such terrain to channel the flows into predictable patterns.&lt;/p&gt;&#xA;&lt;p&gt;Hourly wind direction can regularly be inaccurate for a few reasons:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;low wind speed conditions causes meandering influenced by localized conditions&lt;/li&gt;&#xA;&lt;li&gt;incorrect terrain parameterization can cause systematic bias in particular locations.&lt;/li&gt;&#xA;&lt;li&gt;the timing of shifting winds can be off due to small perturbations in the pressure systems not captured by the model&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;In contrast, the occurrence of high wind speeds at the surface can have a lot of confidence and accuracy, which is why weather agencies can issue &amp;quot;high wind alerts&amp;quot; (another binary yes/no event).  However, the timing of pressure system movement is not confident, and modeled hourly surface wind direction can vary greatly throughout the event.&lt;/p&gt;&#xA;&lt;p&gt;Ensembles provide a wealth of information but they are not easily digestible for the public.  Imagine looking at a spaghetti plot of wind direction at the surface; it wouldn't look pretty.  In general, that type of ensemble forecast analysis is done by the scientists who run the model, so they can asses 3D model performance. However, model performance is driven by the atmosphere aloft, so that is where ensemble analysis is useful (e.g. 850 mb, 500 mb, etc.).  See the spaghetti plots on the &lt;a href=&quot;https://psl.noaa.gov/map/images/ens/ens.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCEP ensemble weather model products&lt;/a&gt; as an example.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Visualization Tool at &lt;a href=&quot;http://www.windy.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;www.windy.com&lt;/a&gt;:&lt;/strong&gt;&lt;br /&gt;&#xA;You can do a quick comparison of winds for several different models by selecting the comparison forecast for a single location on the windy.com site (see example below). This can give an idea of how &amp;quot;confident&amp;quot; the wind predictions at the surface are, in a qualitative sense.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hkgch.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hkgch.png&quot; alt=&quot;windy.com Redding, CA forecast&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2021-06-09T04:54:15.447" LastActivityDate="2021-06-09T04:54:15.447" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="22347" PostTypeId="2" ParentId="22343" CreationDate="2021-06-04T20:37:34.593" Score="9" Body="&lt;p&gt;Following up on Farrenthrope's answer (which I think is worthy of acceptance more than this answer) I do want to add additional detail that may not be appropriate as a comment.&lt;/p&gt;&#xA;&lt;p&gt;There is a problem with how we communicate the wind speed and direction that does not fit with ensembles. Often ensembles rely on prior assumptions about the uncertainty distribution of variables like temperature and water vapor (usually the &lt;a href=&quot;https://en.wikipedia.org/wiki/Normal_distribution&quot; rel=&quot;noreferrer&quot;&gt;Gaussian distribution&lt;/a&gt; for the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ensemble_Kalman_filter&quot; rel=&quot;noreferrer&quot;&gt;Ensemble Kalman Filter&lt;/a&gt;). These distributions aren't guaranteed to be accurate, let alone translate across transformations. Things like wind speed and wind direction are applicable and sensible, but require some processing. Wind speed and direction aren't exactly the easiest things to express, but here is an example.&lt;/p&gt;&#xA;&lt;p&gt;Let's consider a wind vector that we are 100% confident to have a northerly component of 10 kts. But let's say that the east-west component has some uncertainty (let's say ± 5 kts. So the wind speed range would be between 10 and 11.2 kts(&lt;span class=&quot;math-container&quot;&gt;$&#xA;\approx\sqrt{(10 \text{ kts})^2+(\pm 5 \text{ kts})^2}$&lt;/span&gt;). Let's take a look at what the wind vector looks like on a compass (blue arrow is the middle with a wind speed of 10 kts and orange has 11.2 knots):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/dkKER.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dkKER.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;What is the range of the wind direction? It is between 297° and 63°. But is it the purple range or the yellow range? And this is for uncertainty in only one wind component, ignoring the uncertainty in the other component. Things become even more complicated with adding additional uncertainty. But let's move on to another problem with expressing uncertainty with wind forecasts: wind speed.&lt;/p&gt;&#xA;&lt;p&gt;Farrenthorpe's answer is good, but there is a flaw with reporting the standard deviation. Without reporting additional statistical moments (like &lt;a href=&quot;https://en.wikipedia.org/wiki/Skewness&quot; rel=&quot;noreferrer&quot;&gt;skewness&lt;/a&gt;) or making assumptions about the uncertainty distribution, the user may make an inference based on faulty assumptions. For example if the prediction is 8.5 knots with a standard deviation of 10 knots, then there could be a perception that the wind speed can be negative, which is unrealistic and unphysical.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-06-04T20:37:34.593" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="22348" PostTypeId="1" AcceptedAnswerId="22349" CreationDate="2021-06-04T21:56:22.150" Score="5" ViewCount="1049" Body="&lt;p&gt;I can't find a good way to say this but, if I had some info about an earthquake (i.e. magnitude 8, originating in water) and if I had a distance (i.e. 850 miles/ 1370 km) could I calculate what it would be if that specific location was the epicenter? So, maybe it would be like a 3 or 4 maybe?&lt;/p&gt;&#xA;&lt;p&gt;I'm looking for a formula or calculator. If it is not possible, please tell me! It is fine if it is rough.&lt;/p&gt;&#xA;" OwnerUserId="22673" OwnerDisplayName="Nikhil R." LastEditorUserId="7314" LastEditDate="2021-06-08T15:03:46.283" LastActivityDate="2021-06-08T15:03:46.283" Title="What Magnitude does it Feel Like when Far Away in an Earthquake?" Tags="|earthquakes|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22349" PostTypeId="2" ParentId="22348" CreationDate="2021-06-05T02:04:27.373" Score="7" Body="&lt;p&gt;The question doesn't really make sense.&lt;/p&gt;&#xA;&lt;p&gt;The Richter and other &lt;a href=&quot;https://en.wikipedia.org/wiki/Seismic_magnitude_scales&quot; rel=&quot;noreferrer&quot;&gt;seismic magnitude scales&lt;/a&gt; are measures of how much energy was released by an earthquake or how much work it did.  An earthquake doesn't &amp;quot;feel like&amp;quot; any particular magnitude at any given point; rather, magnitude is an inherent attribute of the earthquake itself.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Feels like&amp;quot; is measured on &lt;a href=&quot;https://en.wikipedia.org/wiki/Seismic_intensity_scales&quot; rel=&quot;noreferrer&quot;&gt;seismic intensity scales&lt;/a&gt; such as the Mercalli scale.  These measure the peak acceleration or velocity at a given point, or the damage done by the earthquake.  Intensity is influenced by many things, such as the depth of the earthquake, the distance to the ruptured section of the fault, and the local surface material.&lt;/p&gt;&#xA;&lt;p&gt;Translating between the two is difficult, and requires knowing the detailed geology of the area involved.  The picture below is a USGS map of two earthquakes of comparable magnitude, the &lt;a href=&quot;https://en.wikipedia.org/wiki/1994_Northridge_earthquake&quot; rel=&quot;noreferrer&quot;&gt;1994 Northridge earthquake&lt;/a&gt; and an 1895 earthquake on the &lt;a href=&quot;https://en.wikipedia.org/wiki/New_Madrid_Seismic_Zone#1812%E2%80%931900&quot; rel=&quot;noreferrer&quot;&gt;New Madrid Seismic Zone&lt;/a&gt;.  In both cases, the outer zone is an intensity of Mercalli II or above, while the inner zone is an intensity of Mercalli VI or above.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yP3vh.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yP3vh.jpg&quot; alt=&quot;A map of the United States, showing the effects of two earthquakes.  The 1994 Northridge earthquake affected an area consisting mostly of southern California, with a small damage area.  The 1895 New Madrid earthquake affected most of the eastern United States, with a damage area covering large parts of Tennessee, Kentucky, Ohio, Indiana, Illinois, and Missouri.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2643" LastActivityDate="2021-06-05T02:04:27.373" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22350" PostTypeId="2" ParentId="20876" CreationDate="2021-06-05T11:13:18.393" Score="5" Body="&lt;p&gt;Waves travel over the ocean surface with columns of water molecules moving in a circular motion, as seen here.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/e3KDB.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/e3KDB.png&quot; alt=&quot;rotating formation of water molecules under waves&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As you can see, when the waves reach shallow ground, the friction of the molecules over the seabed causes it to topple over and break.&#xA;If in your case there is a tall obstacle under the water instead of the gradual slope, the wave energy will but cut as the obstacle blocks the oncoming motion, causing it to break.&lt;/p&gt;&#xA;&lt;p&gt;If the obstacle ends and the beach returns to its original slope and the water deepens again, there will be a sort of conflict between the oncoming wave and a returning backwash (with it's loss of energy from travelling over the obstacle, the wave will not travel too fare before it runs out of energy completely, and gravity pulls the swash back.), creating a 'turbulence' at the base of the obstacle, disrupting any waves passing overhead.&lt;/p&gt;&#xA;&lt;p&gt;In layman's terms, the actual wave will be diminished rapidly, but due to the forced breaking, will appear to be enhanced.&lt;/p&gt;&#xA;" OwnerUserId="22670" LastActivityDate="2021-06-05T11:13:18.393" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22351" PostTypeId="2" ParentId="21316" CreationDate="2021-06-05T11:42:29.190" Score="0" Body="&lt;p&gt;Clouds are heavy. Clouds are a form of stored water, surfing the warm low pressure rising from the Earth's surface, if it weren't for the low pressure constantly rising above the denser high pressure, the clouds would naturally sink to the ground. This is what happens of foggy mornings, where there isn't sufficient low pressure to keep the clouds afloat.&lt;/p&gt;&#xA;&lt;p&gt;What you're witnessing is a sort of intermediary stage where there is an updraft of low pressure, but not enough to keep the clouds high in the sky, so they sink as low as they can to the ground.&lt;/p&gt;&#xA;" OwnerUserId="22670" LastActivityDate="2021-06-05T11:42:29.190" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22352" PostTypeId="2" ParentId="20871" CreationDate="2021-06-05T11:48:25.163" Score="1" Body="&lt;p&gt;Just in case it will save a great deal of time for others in the future, ill recommend the metpy package.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://unidata.github.io/MetPy/latest/api/generated/metpy.calc.specific_humidity_from_dewpoint.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://unidata.github.io/MetPy/latest/api/generated/metpy.calc.specific_humidity_from_dewpoint.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22671" LastActivityDate="2021-06-05T11:48:25.163" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22353" PostTypeId="1" AcceptedAnswerId="22356" CreationDate="2021-06-01T02:45:39.357" Score="2" ViewCount="100" Body="&lt;p&gt;Earth is a very special goldilocks planet which somehow maintains a useful thermal range for life.&lt;/p&gt;&#xA;&lt;p&gt;In order to do this, it must have some function of absorbing and releasing energy.  If it absorbed too much, it would get too hot.  If it released too much, it would get too cold.&lt;/p&gt;&#xA;&lt;p&gt;From what I can research, some of the major factors in keeping Earth from getting &amp;quot;too hot&amp;quot; are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the magnetic field diverting solar winds and charged particles (&lt;a href=&quot;https://earthscience.stackexchange.com/a/8730&quot;&gt;similar question&lt;/a&gt;, &lt;a href=&quot;https://ase.tufts.edu/cosmos/view_overview.asp?id=29#:%7E:text=The%20Earth%27s%20dipolar%20magnetic%20field,and%20protons%20around%20the%20Earth.&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA's Cosmos&lt;/a&gt;): without these &amp;quot;the earth would fry&amp;quot;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;seemingly, this is the most important one for stability (??)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;our distance from the sun (which is also a &amp;quot;not too cold&amp;quot; factor&amp;quot;)&lt;/li&gt;&#xA;&lt;li&gt;infrared emissions: basically molecules launching off photons.  any photon emission would work, but infrared is the most common on human inhabitable planets (??)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The &amp;quot;not too cold&amp;quot; factors are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;once again, our distance from the sun being amicable&lt;/li&gt;&#xA;&lt;li&gt;atmospheric absorption of greenhouse gasses (greenhouse effect)&lt;/li&gt;&#xA;&lt;li&gt;?? that's it that I know of&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Overall, it seems like things had to be just perfect to create a planet with a workable balance of magnetic fields, greenhouse gasses, and distance from the sun.  But this is just my layman's understanding.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;What other major vectors/inhibitors/regulators of energy transfer to/from Earth are there?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="22688" OwnerDisplayName="Seph Reed" LastEditorUserId="2958" LastEditDate="2021-06-15T20:11:19.160" LastActivityDate="2021-06-15T20:11:19.160" Title="What are the major factors of energy coming into and leaving the Earth?" Tags="|energy|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="22354" PostTypeId="1" CreationDate="2021-06-05T12:37:01.880" Score="1" ViewCount="39" Body="&lt;p&gt;I had a small quarrel about this on the physics site. A question was asked about what could cause a change in the rotation speed of the Earth. In addition to the answers given I proposed the possibility that if the liquid core would solidify this would result in an increasing rotation speed.&lt;/p&gt;&#xA;&lt;p&gt;I thought the same could happen if the matter currents giving rise to Earth's magnetic field changed direction, this would cause an increase in speed too. That is, if the currents have the right direction. The reversal of the currents' momentum (&lt;em&gt;if&lt;/em&gt; such currents exist but I don't see why not) could also &lt;em&gt;de&lt;/em&gt;crease the speed.&lt;/p&gt;&#xA;&lt;p&gt;So, are these scenarios realistic?&lt;/p&gt;&#xA;" OwnerUserId="5945" LastEditorUserId="2470" LastEditDate="2021-06-05T15:28:36.787" LastActivityDate="2021-06-05T15:28:36.787" Title="Can changing magnetic fields or a solidifying core cause the Earth to rotate faster?" Tags="|geomagnetism|earth-rotation|core|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="22355" PostTypeId="1" AcceptedAnswerId="22364" CreationDate="2021-06-05T18:51:42.370" Score="4" ViewCount="71" Body="&lt;p&gt;I just came across an interesting article which discusses a form of agriculture the authors call 'forest gardens': &lt;a href=&quot;https://nationalpost.com/news/canada/ancient-indigenous-forest-gardens-still-yield-bounty-150-years-later-study&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://nationalpost.com/news/canada/ancient-indigenous-forest-gardens-still-yield-bounty-150-years-later-study&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;While the authors' interest seems to be the persistence of the forest gardens even when untended for a long time, mine is in the tradeoffs involved with that form of agriculture; I'm used to the idea that you grow just one crop per field (perhaps rotating, but one at a time). Yet,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In coastal forest gardens, crabapple, hazelnut, wild cherry and plum trees provide a canopy, shielding plants such as cranberry, elderberry and hawthorn, wild ginger and wild rice root.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So why did those people mix the various trees, bushes, herbs and rice that way? Presumably there was some advantage in doing it like that, but the explanation cannot explain too much; it cannot be of the form '... so that's why it's the most efficient way in general', because that would incorrectly predict such mixed gardens in the rest of the world.&lt;/p&gt;&#xA;&lt;p&gt;The area in question seems to be around mid fifties latitude, and the article does casually use the word 'shielding', so my first thought was perhaps that far north, herbs and bushes gain more benefit from having trees around to block the freezing wind, than they lose from having some of the sunlight blocked. Except it's also on the coast, and apparently does not get much snow in winter. It presumably gets ocean storms, but so do coastal regions in general, and I'm not aware of any other coastal regions having mixed forest gardens.&lt;/p&gt;&#xA;&lt;p&gt;So what is the reason for that form of agriculture in that location?&lt;/p&gt;&#xA;" OwnerUserId="7911" LastEditorUserId="2470" LastEditDate="2021-09-16T15:45:13.167" LastActivityDate="2021-09-16T15:45:13.167" Title="Why are mixed crops cultivated in high latitude coastal environments?" Tags="|agriculture|coastal|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22356" PostTypeId="2" ParentId="22353" CreationDate="2021-06-05T22:24:24.450" Score="3" Body="&lt;p&gt;Depending on your definition of &amp;quot;major&amp;quot;, here are a few things I could think of that affect our &amp;quot;Goldilocks&amp;quot; temperature that humans are so fond of.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Your list:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the magnetic field&lt;/li&gt;&#xA;&lt;li&gt;distance from the sun&lt;/li&gt;&#xA;&lt;li&gt;the greenhouse effect:&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;em&gt;infrared radiation from atmosphere&lt;/em&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;em&gt;infrared absorption by the atmosphere from Earth/atmosphere.&lt;/em&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;Other stuff:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;geothermal energy (direct heat source, though small)&lt;/li&gt;&#xA;&lt;li&gt;radioactive decay (direct heat source, though small)&lt;/li&gt;&#xA;&lt;li&gt;intensity of the sun (this changes), which is coupled with distance to the sun&lt;/li&gt;&#xA;&lt;li&gt;spin rate of Earth (if it was too slow, solar heating would be extremely different)&lt;/li&gt;&#xA;&lt;li&gt;axial tilt of Earth (if it was too much, solar heating would be extremely different)&lt;/li&gt;&#xA;&lt;li&gt;fraction of Earth covered by water (affects albedo and ability of weather systems to form that act to regulate temperature over land)&lt;/li&gt;&#xA;&lt;li&gt;volcanic activity (more activity would lead to more particulate in atmosphere and blocking of sunlight)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I'm sure there are more... though I would say that all factors that have influence on temperature should be on both the hot and cold list.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2021-06-06T00:05:41.217" LastActivityDate="2021-06-06T00:05:41.217" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22357" PostTypeId="1" CreationDate="2021-06-06T07:12:54.493" Score="1" ViewCount="31" Body="&lt;p&gt;There are parts inside the Earth (near the core) that are liquid. Presumably causing the Earth's magnetic field (though there are celestial bodies that are completely solid while they have a magnetic field around them).&lt;/p&gt;&#xA;&lt;p&gt;In a comment to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/22354/can-changing-magnetic-fields-or-a-solidifying-core-cause-the-earth-to-rotate-fas&quot;&gt;another question&lt;/a&gt;, JeopardyTempest pointed out that solid iron and nickel (the main liquid stuff) has a density that is 15% higher than that of the liquid state. I can imagine that if this liquid stuff turns solid (though I'm not sure this will happen) this will affect the solid parts. But how?&lt;/p&gt;&#xA;" OwnerUserId="5945" LastEditorUserId="2470" LastEditDate="2021-06-06T09:18:45.217" LastActivityDate="2021-06-06T09:18:45.217" Title="If all liquid stuff inside the Earth turned solid, what would be the effect?" Tags="|geomagnetism|earth-rotation|crust|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22359" PostTypeId="1" CreationDate="2021-06-06T13:22:22.950" Score="5" ViewCount="225" Body="&lt;p&gt;This question is a continuation of my previous question: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/21322/questions-about-the-validity-of-a-certain-model-for-tidal-resonance-at-the-bay-o&quot;&gt;Questions about the validity of a certain model for tidal resonance at the Bay of Fundy&lt;/a&gt;. I need to answer this question in order to return to my previously posted question and test the validity of the model described there.&lt;/p&gt;&#xA;&lt;p&gt;As far as i understand, the northeastern part of the Gulf of Maine, also called the Bay of Fundy, is the only resonant part of the whole body of water in the Gulf of Maine (which means its natural period is very close to that of the M2 tide component). Therefore, it's logical to assume that the water level at its entrance is fixed to the Atlantic ocean water level, while the tidal range rises higher and higher as we go more and more into the bay; the water level inside the bay is a standing wave with a fixed end at its entrance and a free end at the coasts of its narrow part (this model is called &amp;quot;&lt;em&gt;&lt;strong&gt;open harbour&lt;/strong&gt;&lt;/em&gt;&amp;quot;). This description of the situation seems to fit all discussions of tidal resonance phenomenas that i found up to now.&lt;/p&gt;&#xA;&lt;p&gt;According to this rational, the tidal range at the bay entrance should be similar to that of other coasts near the Atlantic, which is &lt;span class=&quot;math-container&quot;&gt;$1-2$$\text{m}$&lt;/span&gt;. However, loooking into maps of the tidal range at the bay of fundy, like this one,&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4l7gw.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4l7gw.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;reveals that already at the entrance to the bay, the tidal range is about &lt;span class=&quot;math-container&quot;&gt;$5-6\text{m}$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Therefore, my questions are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;If the water level at the entrance to the bay of fundy is fixed to the Atlantic ocean water level, why is the tidal range there so large?&lt;/li&gt;&#xA;&lt;li&gt;What are, and this is a general question, the physical effects that govern the enhancement of tidal waves? and i mean other effects than tidal resonance. Is Green's law (which is often used to explain the wave shoaling of tsunamies and other shallow water waves), which might be applied to tidal waves (as they are shallow water waves), relevant here? and if the answer is yes, than why is it relevant only to the Gulf of Maine and not to other US/Canadian coasts?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="17830" LastActivityDate="2021-06-07T05:31:48.963" Title="Why is the tidal range at the entrance to the bay of fundy so high?" Tags="|oceanography|tides|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="22360" PostTypeId="2" ParentId="22359" CreationDate="2021-06-07T05:31:48.963" Score="-1" Body="&lt;p&gt;The Bay of Fundy is shaped like a funnel, which amplifies the tidal magnitude, as the water is &amp;quot;squashed&amp;quot; into the bay. There are several other funnel-shaped bays with a large tidal amplitude around the world, e.g. Bristol Channel in Wales, UK.&lt;/p&gt;&#xA;" OwnerUserId="18907" LastActivityDate="2021-06-07T05:31:48.963" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22361" PostTypeId="1" CreationDate="2021-06-07T21:49:06.233" Score="1" ViewCount="33" Body="&lt;p&gt;My understanding is that with the relatively recent discovery of many more volcanoes on the Mid-Atlantic Ocean Ridge (and perhaps other ocean ridges) and more deep trenches with thermal vents, that the estimates of the total thermal energy transfer (e.g., in Joules per year) into the oceans have increased significantly, to the point where this heat may need to be factored into climate models, (though still small), for future estimates of ocean temperatures.&lt;/p&gt;&#xA;" OwnerUserId="22690" LastActivityDate="2021-06-07T21:49:06.233" Title="What is the most current thinking on the amount of heat transferred into the oceans from underwater thermal vents and volcanoes?" Tags="|oceanography|volcanology|geothermal-heat|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22362" PostTypeId="1" CreationDate="2021-06-08T03:56:22.520" Score="2" ViewCount="183" Body="&lt;p&gt;In that the green house effect, as caused by various atmospheric gases (e.g., H&lt;sub&gt;2&lt;/sub&gt;O, CO&lt;sub&gt;2&lt;/sub&gt;, CH&lt;sub&gt;4&lt;/sub&gt;, etc), acts as an insulating layer which only retards the escape of heat from the planet, it would seem that the above statement is correct. Yet many commentaries on climate change seem to allow for the potential of much greater heating due to &amp;quot;run-away&amp;quot; feedback effects.&lt;/p&gt;&#xA;&lt;p&gt;Such &amp;quot;run-away&amp;quot; heating scenarios do seem to violate the Stephan-Boltzman Law, and the general laws of thermodynamics, even after allowing for the &amp;quot;back-radiation&amp;quot;, that effectively provides the &amp;quot;insulation&amp;quot; that slows the escape of the long-wave (i.e., infrared) radiation. While &amp;quot;greenhouse&amp;quot; gas insulation is the colder body (in daytime),  it cannot do a net transfer heat to the plant's surface, which is the hotter body. At night time, however, the greenhouse gas may be the hotter body -- for a while -- and thus transfer some heat back to surface, before morning sun rise.  This is how I see it. Is that wrong?&lt;/p&gt;&#xA;" OwnerUserId="22690" LastEditorUserId="2470" LastEditDate="2021-06-08T15:29:27.260" LastActivityDate="2021-06-15T00:05:52.033" Title="Can a planet be heated by the green house effect to a temperature higher than that created by its incident and net absorbed, peak external radiation?" Tags="|geophysics|climate|greenhouse-gases|radiation-balance|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22363" PostTypeId="2" ParentId="17431" CreationDate="2021-06-08T18:36:50.417" Score="3" Body="&lt;p&gt;It should be noted that NetCDF data just describes the format that the data is in. One dataset that I know of (&lt;a href=&quot;https://www.ncdc.noaa.gov/ibtracs/index.php?name=ib-v4-access&quot; rel=&quot;nofollow noreferrer&quot;&gt;IBTrACS&lt;/a&gt;) contains data that is not gridded data, and also contains a landmask. But this is besides your question.&lt;/p&gt;&#xA;&lt;p&gt;To rephrase your question: How can I determine the orientation of the coastline in a gridded dataset?&lt;/p&gt;&#xA;&lt;p&gt;Well, one way is using mathematics. Let's call the boolean landmask variable &lt;span class=&quot;math-container&quot;&gt;$L$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$L=\{^{0 \text{ if land}}_{1\text{ if water}}$&lt;/span&gt; Then the gradient is &lt;span class=&quot;math-container&quot;&gt;$$\nabla L =\{^{&amp;lt;\frac{\delta L}{\delta x},\frac{\delta L}{\delta y}&amp;gt; \text{ at the coastline}}_{\vec{0} \text{ not at the coastline}}$$&lt;/span&gt; Let's look at just the coastline. The angle is &lt;span class=&quot;math-container&quot;&gt;$\arctan2(\frac{\delta L}{\delta x},\frac{\delta L}{\delta y})$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Now if you want to find out the angle difference between the coast and the wind, then you can use the &lt;a href=&quot;https://en.wikipedia.org/wiki/Dot_product&quot; rel=&quot;nofollow noreferrer&quot;&gt;properties of the dot product&lt;/a&gt; to find the angle difference. That is &lt;span class=&quot;math-container&quot;&gt;$$\delta \phi=\arccos\left(\frac{\nabla L \cdot \vec{v}}{|\nabla L||\vec{v}|}\right)=\arccos\left(\frac{u\frac{\delta L}{\delta x}+v\frac{\delta L}{\delta y}}{\sqrt{u^2+v^2}\sqrt{\left(\frac{\delta L}{\delta x}\right)^2+\left(\frac{\delta L}{\delta y}\right)^2}}\right)$$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-06-08T18:36:50.417" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22364" PostTypeId="2" ParentId="22355" CreationDate="2021-06-09T03:21:45.323" Score="3" Body="&lt;p&gt;It is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Companion_planting&quot; rel=&quot;nofollow noreferrer&quot;&gt;Companion planting&lt;/a&gt;, and it is actually fairly common with hand tended fields. It does not work well with mechanized agriculture which is why you don't see it much in large scale farming. It is however, fairly common in gardens and non-industrial farming because they do work well. It has a variety of benefits depending on what exactly you are planting.&lt;/p&gt;&#xA;&lt;p&gt;The benefits here are fourfold at least. First is cramming many plants of differing heights into the same place. You also get the benefit that the large tree species provide a place for the ginger vine to grow. Some of these plants are nitrogen fixing so they help fertilize the soil, and may even share nitrogen directly via rhizome transport, basically crop rotation without the rotation. Finally ginger prefers shade to full sun.&lt;/p&gt;&#xA;&lt;p&gt;There may be other benefits in this case I am just not seeing, like pest control.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="2470" LastEditDate="2021-06-09T05:15:56.137" LastActivityDate="2021-06-09T05:15:56.137" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22365" PostTypeId="1" CreationDate="2021-06-09T08:56:52.577" Score="3" ViewCount="92" Body="&lt;p&gt;I am attempting to calculate wet bulb temperatures needed for agricultural curing processes. I am trying to do this by inferring the wet-bulb value from relative humidity and dry bulb temperature.&lt;/p&gt;&#xA;&lt;p&gt;The problem is this: My measured relative humidity using a shtetl 30 sensor is about 45% when, according to the 4 degree difference between dry (28 deg) and wet bulb (24 deg) , it should be reading 75%.&lt;/p&gt;&#xA;&lt;p&gt;What am I missing? Why is my relative humidity sensor getting it so wrong?&lt;/p&gt;&#xA;&lt;p&gt;I tried another sensor brand (albeit with the same RH method of measurement) and likewise got humidity in the region of 45% when it should have read 75%.&lt;/p&gt;&#xA;&lt;p&gt;Has anyone else experienced this issue? If so, how did you resolve it?&lt;/p&gt;&#xA;&lt;p&gt;Many thanks in advance!&lt;/p&gt;&#xA;" OwnerUserId="22689" LastEditorUserId="22689" LastEditDate="2021-06-09T14:53:48.223" LastActivityDate="2021-06-09T14:53:48.223" Title="Incorrect relative humidity with SHT30 when comparing to dry and wet bulb calculation" Tags="|humidity|environmental-sensors|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22366" PostTypeId="2" ParentId="22344" CreationDate="2021-06-09T11:08:54.950" Score="4" Body="&lt;p&gt;No such thing exists.&lt;/p&gt;&#xA;&lt;p&gt;Some of the data you're looking for may be available from government geological surveys.&lt;/p&gt;&#xA;&lt;p&gt;For example, the Australian state of New South Wales provides this in their online map tool:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://minview.geoscience.nsw.gov.au&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://minview.geoscience.nsw.gov.au&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Click &amp;quot;Add layer&amp;quot;, then &amp;quot;Geochemistry&amp;quot;, then &amp;quot;All surface geochemistry&amp;quot;. MinView from GSNSW is probably one of the better tools, anywhere in the world. Finding something like that on a global scale is impossible. You will be probably luckier with the more developed countries which invest quite a lot into this thing (like Australia and its states).&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-06-09T11:08:54.950" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22368" PostTypeId="1" CreationDate="2021-06-09T21:06:56.253" Score="4" ViewCount="398" Body="&lt;p&gt;I have been trying to implement the IGRF-13 geomagnetic model on my own in C code. I have followed the equations from the website below and I am getting correct results for the B&lt;span class=&quot;math-container&quot;&gt;$_{\phi}$&lt;/span&gt; and B&lt;sub&gt;r&lt;/sub&gt; magnetic field strength components.&lt;/p&gt;&#xA;&lt;p&gt;But right now I am completely stuck on the B&lt;span class=&quot;math-container&quot;&gt;$_{\theta}$&lt;/span&gt; component which requires calculating the Partial derivatives of the Schmidt Normalized Associated Legendre Polynomials with respect to theta according to equation 3b.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/AcGwh.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AcGwh.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now, how do I do that? The recursive equations 19 a, b, and c are not producing the correct results, and there is no information on the internet about this.&lt;/p&gt;&#xA;&lt;p&gt;I would really appreciate it if someone could provide a sample code that calculates the &amp;quot;Partial derivatives of the Associated Legendre Polynomials&amp;quot; or maybe provide the equations that will allow me to calculate them.&lt;/p&gt;&#xA;&lt;p&gt;Reference: &lt;a href=&quot;https://hanspeterschaub.info/Papers/UnderGradStudents/MagneticField.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mathematical Modeling of Earth’s Magnetic Field&lt;/a&gt; (PDF)&lt;/p&gt;&#xA;" OwnerUserId="22724" LastEditorUserId="18088" LastEditDate="2022-07-11T17:26:36.330" LastActivityDate="2022-07-11T17:26:36.330" Title="IGRF -13 Geomagnetic field, Calculating Partial Derivatives of Legendre Polynomials" Tags="|geophysics|geomagnetism|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22369" PostTypeId="2" ParentId="21296" CreationDate="2021-06-10T17:50:08.667" Score="4" Body="&lt;p&gt;Cyclone tracks are influenced by the environmental wind. These can include subtropical ridges, mid latitude upper level troughs , other tropical cyclones (Fujiwara effect) and other transient highs and lows. Specifically in the Western North Pacific there are two synoptic scale phenomena that can influence cyclone tracks - &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_upper_tropospheric_trough&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tropical Upper Tropospheric Trough&lt;/a&gt; and the western Pacific sub tropical  high ridge - &lt;a href=&quot;https://link.springer.com/article/10.1007/s00382-019-04705-4#:%7E:text=In%20both%20early%20and%20late,is%20stronger%20in%20late%20summer.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Subseasonal zonal variability of the western Pacific subtropical high in summer: climate impacts and underlying mechanisms&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;While the tropical upper tropsopheric trough is known to influence cyclone tracks as shown in this paper &lt;a href=&quot;https://journals.ametsoc.org/view/journals/wefo/24/5/2009waf2222181_1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;A Conceptual Model for the Influence of TUTT Cells on Tropical Cyclone Motion in the Northwest Pacific Ocean&lt;/a&gt; we are going to focus on the influence of the West Pacific Sub Tropical High as that is directly related to OP's question.&lt;/p&gt;&#xA;&lt;p&gt;A recent paper titled &lt;a href=&quot;https://www.mdpi.com/2073-4433/11/5/543&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Climatological Analysis of Typhoon Tracks, Steering Flow, and the Pacific Subtropical High in the Vicinity of Taiwan and the Western North Pacific&lt;/a&gt; details the impact of the subtropical west pacific ridge on the deep layer mean steering flow of tropical cyclones that make landfall on the Taiwan mainland .&lt;/p&gt;&#xA;&lt;p&gt;The West Pacific Sub Tropical High is a ridge that exhibits structure from 850 hPa to 500 hPa.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/K5tPD.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/K5tPD.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt; - Image taken from this paper - &lt;a href=&quot;https://www.mdpi.com/2073-4433/11/5/543&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Climatological Analysis of Typhoon Tracks, Steering Flow, and the Pacific Subtropical High in the Vicinity of Taiwan and the Western North Pacific&lt;/a&gt;. The image is the July August September 500 hPa geopotential  height climatological value over the western pacific.&lt;/p&gt;&#xA;&lt;p&gt;The above displayed image taken from the linked paper summarizes the flow of TCs in the vicinity of Taiwan. Assuming the subtropical ridge western extent is located between Taiwan and Kyushu(shown in blue dotted line)  the mean steering flow is such that it steers tropical cyclones towawrds the Taiwan coast. On the other hand if it shrinks further towards the east (shown in red dotted line) all cyclones generated at low latitudes will still be guided towards Taiwan but the steering flow at the edge of the ridge would allow the cyclone to recurve and go towards the islands of Japan.&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2021-06-11T04:38:06.760" LastActivityDate="2021-06-11T04:38:06.760" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="22370" PostTypeId="1" CreationDate="2021-06-10T18:50:59.673" Score="7" ViewCount="493" Body="&lt;p&gt;I am curious of the lower boundary of soil. Soil is formed after going through complex processes and it has been through coevolution with living organisms. According to the &lt;a href=&quot;https://www.nrcs.usda.gov/wps/portal/nrcs/detail/soils/edu/?cid=nrcs142p2_054280&quot; rel=&quot;nofollow noreferrer&quot;&gt;USDA&lt;/a&gt;, for soil classification, the lower boundary of soil is arbitrarily set at 2 m. So, this is obviously not the actual depth. Yost and Hartemink (2020), in a review article mentioned soil depth/thickness:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A general term for the vertical dimension of the soil. Some authors consider it includes only the solum, some others include the solum plus the C and the G horizons (whether they represent or&#xA;not the soil parent material), and some others consider it as equivalent to the root-restricting&#xA;depth.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Considering C horizon while calculating the soil depth is also stated in a research by Richter and Markewitz(1995). They have mentioned varying depth of soils from 20 m to 100 m depending on spatial variations in climatic features. So, till which distance from our earth's surface is soil? Is there any standard depth of soil?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;References:&lt;/strong&gt; &lt;br&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Yost, J.L., Hartemink, A.E. (2020). &lt;em&gt;How deep is the soil studied – an analysis of four soil science journals&lt;/em&gt;. Plant Soil 452, 5–18. &lt;a href=&quot;https://doi.org/10.1007/s11104-020-04550-z&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1007/s11104-020-04550-z&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Richter, D., &amp;amp; Markewitz, D. (1995). &lt;em&gt;How Deep Is Soil?&lt;/em&gt; BioScience, 45(9), 600-609. doi:10.2307/1312764&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="22648" LastEditorUserId="22648" LastEditDate="2021-09-09T06:04:48.813" LastActivityDate="2021-09-09T06:04:48.813" Title="How deep is soil?" Tags="|soil|soil-science|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22371" PostTypeId="1" AcceptedAnswerId="22378" CreationDate="2021-06-11T00:00:20.670" Score="11" ViewCount="5305" Body="&lt;p&gt;Desalinating ocean water takes seawater, separates the fresh water from the brine, and usually pumps the brine back into the ocean. But what if we &lt;em&gt;didn't&lt;/em&gt; pump the brine back into the ocean? (For example, if we left it out to dry in the sun and then buried the powder that's left.) If we did this long enough, would it eventually turn the world's oceans into freshwater and harm ocean life?&lt;/p&gt;&#xA;" OwnerUserId="22734" LastEditorUserId="6467" LastEditDate="2022-01-12T22:59:30.453" LastActivityDate="2022-01-12T22:59:30.453" Title="While desalinating ocean water, would it be bad if we didn't pump the brine back into the ocean?" Tags="|oceanography|water|geoengineering|salinity|" AnswerCount="7" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="22372" PostTypeId="2" ParentId="22371" CreationDate="2021-06-11T02:27:18.370" Score="1" Body="&lt;p&gt;Think of what happens with the fresh water that we extract via desalination. It's used for drinking, general water supply, farming and some other industries. In either case it will either eventually evaporate and eventually end up in the ocean or it is discharged back into the ocean.&lt;/p&gt;&#xA;&lt;p&gt;Some water is of course lost in the process, but it's a relatively small amount so overall should not affect ocean's salinity, likely to have a negligible effect compared to the existing trend of increasing salinity due to anthropogenic climate change. There are more details in the linked pdf - &lt;a href=&quot;https://www.mdpi.com/2077-1312/5/4/57/pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Regime Changes in Global Sea Surface Salinity Trend&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18158" LastEditorUserId="21672" LastEditDate="2021-06-11T11:37:57.747" LastActivityDate="2021-06-11T11:37:57.747" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22373" PostTypeId="2" ParentId="22362" CreationDate="2021-06-11T02:44:47.000" Score="1" Body="&lt;p&gt;We'll take an example of Venus as a poster child for runaway greenhouse effect.&lt;/p&gt;&#xA;&lt;p&gt;First of all, let's talk of day/night changes. At the surface level there is little to no change as Venus has an albedo of 0.77, i.e. its atmosphere reflects back 77% of light. Compare this to Earth's albedo of 0.3. So in the overall energy balance of Venusian atmosphere the amount of heat coming from the Sun plays a rather small role and most of it will affect only the upper layers of the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;And even what light is not immediately reflected back is mostly absorbed by the atmosphere and as a result the day/night temperature changes are practically nonexistent. The lower atmosphere has approximately the same temperature during day or night, at the equator or at the pole.&lt;/p&gt;&#xA;&lt;p&gt;At the same time, like most of terrestrial planets Venus continues to produce heat primarily as a result of decay of radioactive elements in the mantle. This heat replaces the amount that is lost from the atmosphere into space.&lt;/p&gt;&#xA;&lt;p&gt;What results is a stable system and really the only thing that can affect it at this stage is the gradual reduction of the nuclear decay heat over time.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;EDIT:&lt;/strong&gt;&#xA;Having a very long discussion in the comments so I figured I'll update the post to better explain what I meant in the post.&lt;/p&gt;&#xA;&lt;p&gt;A planet's atmosphere is a thermodynamic system that in the case of Venus appears to be in the state of equilibrium, i.e. heat received in the system equals heat lost to space primarily via IR radiation.&lt;/p&gt;&#xA;&lt;p&gt;The main parts of planetary energy balance are as follows: incoming solar radiation and geothermal heat as sources of income and loss is primarily radiative.&lt;/p&gt;&#xA;&lt;p&gt;Geothermal heat also consists of residual heat left over from planet's formation and additional heat generated by the decay of radionuclides. In the case of the Earth geothermal heat is &lt;a href=&quot;https://se.copernicus.org/articles/1/5/2010/&quot; rel=&quot;nofollow noreferrer&quot;&gt;estimated at some 47 TW&lt;/a&gt; about half of which is estimated to come from the residual heat and half - from radioactive decay. I couldn't find any reliable sources for Venus, but due to similarities in composition it's reasonable to say that it would exhibit similar energy flux but due to lover volume it's likely to be around 40 TW.&lt;/p&gt;&#xA;&lt;p&gt;So now the overall simplistic view at the components that result in constant atmospheric temperature of Venus:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Albedo of 0.77 limits the amount of solar radiation from an initial flux of &lt;span class=&quot;math-container&quot;&gt;$\approx 2601 W/m^2$&lt;/span&gt; to only about &lt;span class=&quot;math-container&quot;&gt;$157 W/m^2$&lt;/span&gt; &lt;a href=&quot;http://lasp.colorado.edu/%7Eespoclass/ASTR_5835_2015_Readings_Notes/Titov_Et_Al-EVTP.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;enter link description here&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Additional minor energy income comes from planet's interior as discussed above.&lt;/li&gt;&#xA;&lt;li&gt;Finally, heat escapes primarily via IR radiation.&lt;/li&gt;&#xA;&lt;li&gt;High density of atmosphere distributes energy more evenly.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="18158" LastEditorUserId="18158" LastEditDate="2021-06-15T00:05:52.033" LastActivityDate="2021-06-15T00:05:52.033" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="22374" PostTypeId="2" ParentId="22371" CreationDate="2021-06-11T04:25:45.077" Score="19" Body="&lt;p&gt;The residue dry powder you refer to is salt.&lt;/p&gt;&#xA;&lt;p&gt;Salt is toxic to most plants. The United Nations claims the world is already &lt;a href=&quot;https://unu.edu/media-relations/releases/world-losing-2000-hectares-of-farm-soil-daily-to-salt-induced-degradation.html&quot; rel=&quot;noreferrer&quot;&gt;losing 2000 hectares per day&lt;/a&gt; of farm land to salt-induced degradation. This is land that is used to feed people.&lt;/p&gt;&#xA;&lt;p&gt;In some situations, salt from affected lands can contaminate underground sources of drinking water, which will affect people, agriculture, wildlife and wilderness.&lt;/p&gt;&#xA;&lt;p&gt;Salt affected land can be &lt;a href=&quot;https://www.britannica.com/science/land-reclamation/Reclamation-of-salt-affected-soils&quot; rel=&quot;noreferrer&quot;&gt;reclaimed&lt;/a&gt;, but it involves leaching out the salt and depositing it elsewhere; usually into rivers that transport it to the ocean. Some of the salt from reclamation is used for industrial purposes.&lt;/p&gt;&#xA;&lt;p&gt;To store salt as you suggest would require the construction of water impervious basins, including the top, that would be unaffected by natural or human influences for perpetuity. Such influences would include: earthquake, ground movements, water inundation of the region either by rain or flooding, digging by animals or humans.&lt;/p&gt;&#xA;&lt;p&gt;In some parts of the world sea water is used to produce salt for human consumption and industrial purposes. Evaporation ponds are created on the coast and the ponds are flooded with sea water, the water evaporates , leaving the salt which is then collected.&lt;/p&gt;&#xA;&lt;p&gt;A smarter way to deal with the brine from desalination plants would be to send the brine to evaporation ponds and collect the salt for human or industrial purposes.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-06-11T04:25:45.077" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22375" PostTypeId="2" ParentId="21330" CreationDate="2021-06-11T04:26:22.967" Score="1" Body="&lt;p&gt;This all comes down to a single issue.&lt;/p&gt;&#xA;&lt;p&gt;Define plate tectonics.&lt;/p&gt;&#xA;&lt;p&gt;There are several ways it can be defined which is why estimates of when it started vary  by more than half the age of the planet. At the broadest definition plate tectonics predates liquid water by a decent margin, by the narrowest it may not even predate multicellular life.&lt;/p&gt;&#xA;&lt;p&gt;Like most process plate tectonics definition varies depending on what factors you consider essential to the process, because in many ways it is part of a continuum of processes, so it comes down to where you draw the artificial line. do you draw the line a the first mantle convection cell, the presence of layered convection cells, the first solid surface rock, A mantle convection speed similar to today, the formation of the moho? Each can give a drastically different date and some can be quite difficult to estimate a time for. Which is one reason the accepted answer to your linked question restates this problem.&lt;/p&gt;&#xA;&lt;p&gt;Importantly I don't know if even answering the question posted will help you with your underlying question, as liquid water could not occur until after the accreting body would be cool enough.&lt;/p&gt;&#xA;&lt;p&gt;I suggest asking your underlying question, &amp;quot;where did the water on earth come from&amp;quot;, it will provide far more constructive answers to your question. one thing we do know is that water would have been very abundant in the suns accretion disk and thus the forming planets, since hydrogen and oxygen are two of of the three most &lt;a href=&quot;https://ui.adsabs.harvard.edu/abs/2009ARA%26A..47..481A/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;abundant elements&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2021-06-11T04:37:10.797" LastActivityDate="2021-06-11T04:37:10.797" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22376" PostTypeId="2" ParentId="22371" CreationDate="2021-06-11T14:28:14.227" Score="34" Body="&lt;p&gt;&lt;strong&gt;What does it take to reduce the salinity?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;The salinity of sea water is around &lt;a href=&quot;https://en.wikipedia.org/wiki/Salinity&quot; rel=&quot;nofollow noreferrer&quot;&gt;35 g/kg&lt;/a&gt;. There are around &lt;a href=&quot;https://en.wikipedia.org/wiki/Ocean&quot; rel=&quot;nofollow noreferrer&quot;&gt;1,350,000,000 km³ of water&lt;/a&gt;, so roughly 1.3x10&lt;sup&gt;21&lt;/sup&gt; kg of seawater (1 kg/l, which is a bit off for saltwater of course, probably by 35 g). Which contains about 4.7x10&lt;sup&gt;19&lt;/sup&gt; kg of salt.&lt;/p&gt;&#xA;&lt;p&gt;To reduce the salinity to just 34 g/kg, you need to extract 1.4x10&lt;sup&gt;18&lt;/sup&gt; kg of salt and store it in a way that it doesn't end up in the oceans again.&lt;/p&gt;&#xA;&lt;p&gt;An estimate of the yearly produced salt is around &lt;a href=&quot;https://en.wikipedia.org/wiki/Salt#Production&quot; rel=&quot;nofollow noreferrer&quot;&gt;3.0x10&lt;sup&gt;11&lt;/sup&gt; kg/yr&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;So you could supply the whole world with salt from the ocean for close to 5 million years and have decreased the salinity only by 1 g/kg. And to get freshwater oceans you need roughly 150 million years at the current rate.&lt;/p&gt;&#xA;&lt;p&gt;I don't know how wildlife reacts to this change, I guess there are highly specialized species which cannot cope with this change, but considering the time frame it would take to desalinate all the oceans, they could evolve I guess.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;How big is a mountain made out of the whole salt?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;If we take sodium chloride (most of it is this) we have a volume of around 2.1x10&lt;sup&gt;7&lt;/sup&gt; km&lt;sup&gt;3&lt;/sup&gt; of salt. &lt;a href=&quot;https://en.wikipedia.org/wiki/Sodium_chloride&quot; rel=&quot;nofollow noreferrer&quot;&gt;(2.17 g/cm&lt;sup&gt;3&lt;/sup&gt; assumed)&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The Mount Everest is estimated with a volume of just around &lt;a href=&quot;https://weightofstuff.com/how-much-does-mount-everest-weigh/&quot; rel=&quot;nofollow noreferrer&quot;&gt;60 km&lt;sup&gt;3&lt;/sup&gt;&lt;/a&gt;. So you need to stow away 350,000 additional Mount Everests.&lt;/p&gt;&#xA;&lt;p&gt;If you dump it all on one spot and the cone would form in a way that the height is half of what the radius is (not sure if that is a reasonable assumption, but with a small amount of salt it looked that way). The resulting salt cone mountain would be 171 km in height.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;I really hope I haven't messed up the trillion and billion things. So stuff could be of by three or six orders of magnitude :-/&lt;/p&gt;&#xA;" OwnerUserId="3073" LastEditorUserId="3073" LastEditDate="2021-06-14T07:41:35.787" LastActivityDate="2021-06-14T07:41:35.787" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="22377" PostTypeId="1" CreationDate="2021-06-11T15:19:29.863" Score="3" ViewCount="205" Body="&lt;p&gt;I am talking to some students about how soil changes, and I've heard from soil samplers that the texture of the soil, i.e. whether it is sand, silt or clay, doesn't change in a human lifetime. It would be great to tell my students how long it does take, but I can't find this information anywhere. Is it something that isn't known? It must be a hard thing to determine?&lt;/p&gt;&#xA;&lt;p&gt;The closest I've come to a statistic is that it takes thousands of years for soil to form, or that only a millimetre of soil forms each year, which is vaguer than I want to be.&lt;/p&gt;&#xA;&lt;p&gt;Can soil chronosequences tell us the rate of weathering?&lt;/p&gt;&#xA;" OwnerUserId="22748" LastEditorUserId="2470" LastEditDate="2021-06-11T15:51:32.253" LastActivityDate="2021-06-11T15:51:32.253" Title="How fast does sand degrade into silt, and silt into clay?" Tags="|geology|soil|weathering|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22378" PostTypeId="2" ParentId="22371" CreationDate="2021-06-11T18:22:50.933" Score="9" Body="&lt;p&gt;The oceans are salty because the slightly acidic rainwater dissolves minerals from ores and rocks and runs into the sea. This is a continual process, a consequence of erosion. However, the salinity of the oceans has been stable for millions of years, indicating that there is an equilibrium between processes in both directions. Salt is removed from the oceans (buried in sediments, evaporation, reaction with basalt, etc.) at the same rate it is added. So if you &lt;em&gt;did&lt;/em&gt; manage to remove enough salt to affect the salinity (which as noted in other answers is infeasible), natural processes of erosion and sedimentation would gradually return it to normal over geological time.&lt;/p&gt;&#xA;" OwnerUserId="22753" LastActivityDate="2021-06-11T18:22:50.933" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22379" PostTypeId="1" CreationDate="2021-06-11T19:31:21.313" Score="4" ViewCount="320" Body="&lt;p&gt;Because of its high flow rate, why isn't the Amazon River one of the top rivers with  the highest potential for hydro electric power potential in the world?&lt;/p&gt;&#xA;" OwnerUserId="22755" LastEditorUserId="6467" LastEditDate="2021-06-13T23:25:25.457" LastActivityDate="2022-01-18T17:05:55.170" Title="Why isn't the Amazon River in the top for the highest hydropower potential" Tags="|hydrology|" AnswerCount="4" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22380" PostTypeId="2" ParentId="22379" CreationDate="2021-06-11T20:57:16.510" Score="3" Body="&lt;p&gt;Typically, a dam creates a stretched basin, not only wide, or / and deep, but long.  Between the point water enters this newly created container, and the exit gates of the dam, water will slow down, and any thing which was floating earlier has plenty time to settle.  While this sedimentation is wanted e.g., in waste water facilities past the biological treatment to remove the &lt;a href=&quot;https://en.wikipedia.org/wiki/Activated_sludge&quot; rel=&quot;nofollow noreferrer&quot;&gt;activated sludge&lt;/a&gt;, it is not good for dams because over time, this build-up of deposit reduces the water (intake) capacity of the dam. And apparently (&lt;a href=&quot;https://en.wikipedia.org/wiki/Amazon_River#Mouth&quot; rel=&quot;nofollow noreferrer&quot;&gt;reference&lt;/a&gt;), the Amazon river carries a lot of mud.&lt;/p&gt;&#xA;&lt;p&gt;In addition, the Amazon is an important route of transportation for goods, population as well as animals. Thus building such road blocks equally  demands the construction (and maintenance) of locks for ships, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Fish_ladder&quot; rel=&quot;nofollow noreferrer&quot;&gt;fish ladders&lt;/a&gt; to compensate at least a little for the impact of a dam.&lt;/p&gt;&#xA;" OwnerUserId="18990" LastActivityDate="2021-06-11T20:57:16.510" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22381" PostTypeId="2" ParentId="22379" CreationDate="2021-06-12T00:48:20.097" Score="11" Body="&lt;p&gt;It has exceptionally little elevation change. 2000 miles (3218 km) from the mouth to the Peru border there is only 300 feet (91 m) of elevation change; an average grade of 0.15 inch per mile (1 in 35200). Apparently that is why so much area if flooded in Brazil during the wet season , there is very little elevation to push the water down river. So although the volume of the &lt;a href=&quot;https://www.britannica.com/place/Amazon-River/Hydrology&quot; rel=&quot;noreferrer&quot;&gt;Amazon&lt;/a&gt; is huge there is no elevation to develop pressure to turn a turbine in a dam.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastEditorUserId="2470" LastEditDate="2021-06-12T09:04:56.687" LastActivityDate="2021-06-12T09:04:56.687" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22382" PostTypeId="2" ParentId="22371" CreationDate="2021-06-13T16:40:25.943" Score="2" Body="&lt;p&gt;Desalination of ocean water costs energy; beside fresh water, you gain salt.  With &lt;em&gt;some additional&lt;/em&gt; energy invested, you could purify this salt consisting  to large extent of sodium chloride (NaCl) which may be used as table salt.  In other places, you mine for rock salt from underground mines, and equally perform a purification of salt, yet without the generation of drinking water.  Thus, there &lt;em&gt;could&lt;/em&gt; be an economic and ecologic benefit to harvest and use both products &lt;em&gt;at once&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;If the purity of the sodium chloride does not pass food quality, nor is used to deice streets (which obviously has ecological implications on its own), then the NaCl isolated may be starting material to prepare other chemicals of large demand; e.g., sodium hydroxyde, hydrogen and chlorine gas by &lt;a href=&quot;https://en.wikipedia.org/wiki/Chloralkali_process&quot; rel=&quot;nofollow noreferrer&quot;&gt;electrolysis&lt;/a&gt; (a subsequent combustion of chlorine with hydrogen yields HCl, its dissolution in  water yields hydrochloric acid), or sodium carbonate in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Solvay_process&quot; rel=&quot;nofollow noreferrer&quot;&gt;Solvay process&lt;/a&gt; (used e.g., in the production of glass).  Depending on the scale of operation, perhaps other compounds than NaCl may be side-products of interest, too.&lt;/p&gt;&#xA;" OwnerUserId="18990" LastActivityDate="2021-06-13T16:40:25.943" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22383" PostTypeId="2" ParentId="20956" CreationDate="2021-06-13T16:52:49.407" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;The Somali Desert is in the rain shadow region of the Ethiopian&#xA;Highlands. This has contributed to the aridity of the region. The&#xA;diversion of moist air to the low-pressure regions in the South West&#xA;Monsoon of Asia.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is a paraphrased piece of text from Quora. It is Notable how dry Somali is, which I regularly notice when looking at maps, how the color changes from green to rust red on a map as you move to Somali&lt;/p&gt;&#xA;&lt;p&gt;The rain shadow effect is the reason of the cause of most deserts that were not victims of the Earth Rotational Adjustments for thousands of years.&lt;/p&gt;&#xA;&lt;p&gt;El Nino is also Contributing to the droughts in Somali according to Wikipedia also Human Conflicts and wars also contribute to droughts that help the desertification of Somali&lt;/p&gt;&#xA;" OwnerUserId="21926" LastActivityDate="2021-06-13T16:52:49.407" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22384" PostTypeId="2" ParentId="22379" CreationDate="2021-06-13T16:59:02.427" Score="-1" Body="&lt;p&gt;According to Worldatlas.com, the Amazon doesn't even make 4th onto the list of the deepest rivers in the world, it's not the longest, although closely trailing the Nile.&lt;/p&gt;&#xA;&lt;p&gt;@Buttonwoods Answer also provides good reasons for why the amazon is not the place for dams,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;In addition, the Amazon is an important route of transportation for&#xA;goods, population as well as animals. Thus building such road blocks&#xA;equally demands the construction (and maintenance) of locks for ships,&#xA;and fish ladders to compensate at least a little for the impact of a&#xA;dam.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="21926" LastActivityDate="2021-06-13T16:59:02.427" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22385" PostTypeId="1" AcceptedAnswerId="23280" CreationDate="2021-06-13T18:00:11.570" Score="4" ViewCount="933" Body="&lt;p&gt;I know that the forecast accuracy for individual days decreases exponentially past 7 days. But what about the ensemble forecasts that give you the general trend for the week after next? &lt;a href=&quot;https://www.cpc.ncep.noaa.gov/products/predictions/814day/interactive/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.cpc.ncep.noaa.gov/products/predictions/814day/interactive/index.php&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;For example, the 8 to 14 day forecast today shows Madison significantly above Normal:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0JKAk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0JKAk.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;What are the chances that the temperatures for the next week will actually will be below the &lt;a href=&quot;https://weatherspark.com/s/12796/3/Average-Winter-Weather-in-Madison-Wisconsin-United-States#Figures-Temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;50th percentile&lt;/a&gt; for that time of year?&lt;/p&gt;&#xA;&lt;p&gt;Bonus: Is there a chart showing how much 8 to 14 day weather forecasting has improved over the years?&lt;/p&gt;&#xA;" OwnerUserId="22387" LastEditorUserId="22387" LastEditDate="2021-12-09T17:40:12.340" LastActivityDate="2023-04-05T09:39:40.977" Title="How accurate is the National Weather Service 8 to 14 Day Outlook?" Tags="|weather-forecasting|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22387" PostTypeId="1" AcceptedAnswerId="22399" CreationDate="2021-06-14T01:59:22.127" Score="3" ViewCount="193" Body="&lt;p&gt;When I started exploring GOES satellite images of cloud cover (such as &lt;a href=&quot;https://www.star.nesdis.noaa.gov/GOES/sector_band.php?sat=G16&amp;amp;sector=gm&amp;amp;band=GEOCOLOR&amp;amp;length=240&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;), I noticed clouds could form from &amp;quot;plumes.&amp;quot; That is, large clouds could sometimes form by billowing up from one or more very small points. For example, this gif created from GOES-East GeoColor band data on June 13 2021:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZjQHv.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZjQHv.gif&quot; alt=&quot;image description: clouds rise from about 10-15 points across the state of Mississippi and begin to combine.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I haven't looked at a huge amount of data, but I have noticed this effect is pretty common and is often seen over the Southeast US, Central America, the Caribbean, and the Gulf Stream out to around the middle of the Atlantic. In other words, warm and wet places. :)&lt;/p&gt;&#xA;&lt;p&gt;My question is: when clouds form in this way, why don't they arise from larger areas -- what makes those specific &amp;quot;cloud source points&amp;quot; special? And when &amp;quot;cloud source points&amp;quot; &lt;em&gt;do&lt;/em&gt; form, what keeps them (usually) localized to small regions -- what keeps these small nucleation points (usually) stable against growth in area?&lt;/p&gt;&#xA;" OwnerUserId="22772" LastActivityDate="2021-06-16T01:01:05.100" Title="Why do clouds sometimes form in &quot;plumes&quot;?" Tags="|meteorology|clouds|mesoscale-meteorology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22388" PostTypeId="2" ParentId="22371" CreationDate="2021-06-14T07:49:42.887" Score="0" Body="&lt;p&gt;Just a rough estimation of your plan. The oceans contain approximately 1.3E9 cubic km of water --&amp;gt; 1,3E18 tonnes (1000kg) of salt water. In there there 3% of salt  --&amp;gt; 3,9E16 tonnes of salt, which would require 1,8E16 m^3 of dry storage. Assuming we make the mountain 3 km high, this would still require 6 million square kilometer of storage, which is almost twice India or 60% of the USA. Good luck on your project :)&lt;/p&gt;&#xA;" OwnerUserId="22774" LastActivityDate="2021-06-14T07:49:42.887" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22390" PostTypeId="1" CreationDate="2021-06-14T12:46:39.340" Score="3" ViewCount="289" Body="&lt;p&gt;Is there any recommended method for finding the optimum number and location of rain gauges over a region based on the data from existing rain gauges. There is one Isohyetal method that does not give the exact location.&lt;/p&gt;&#xA;" OwnerUserId="735" LastActivityDate="2021-10-22T15:29:39.007" Title="Find optimum number and location of rain gauges" Tags="|meteorology|precipitation|rainfall|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22391" PostTypeId="2" ParentId="22368" CreationDate="2021-06-14T19:37:17.677" Score="1" Body="&lt;p&gt;I don't have a specific reference that defines the recursion in the right form, but I've transcribed it from code I have that I've verified the output of. I think you want these, but please correct me if this doesn't give the result you expect:&lt;/p&gt;&#xA;&lt;p&gt;Where &lt;code&gt;P(n,m)&lt;/code&gt; is the Schmidt normalized associated Legendre polynomial of degree &lt;code&gt;n&lt;/code&gt; and order &lt;code&gt;m&lt;/code&gt;, and &lt;code&gt;dP(n,m)&lt;/code&gt; is the derivative with respect to co-latitude &lt;code&gt;theta&lt;/code&gt;.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;dP(0, 0) = 0&#xA;dP(1, 1) = cos(theta)&#xA;dP(n, n) = sqrt(1 - 1/(2n))*(sin(theta)*dP(n-1, n-1) + cos(theta)*P(n-1, n-1))&#xA;dP(n, m) = (2n - 1)/sqrt(n^2 - m^2)*(cos(theta)*dP(n-1, m) - sin(theta)*P(n-1, m)) - sqrt(((n-1)^2 - m^2)/(n^2 - m^2))*dP(n-2, m)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;I'm sure there is an IGRF implementation in C somewhere, but you can find C code for a different model that contains the required Legendre functionality &lt;a href=&quot;https://geomag.us/models/pomme11.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Also check the implementation of the Legendre polynomials you are using and whether they include the Condon-Shortley phase factor of &lt;code&gt;(-1)^m&lt;/code&gt;, if they do, the normalisations also need to include it, so that it ultimately cancels back out. It is standard in geomagnetism to not apply this factor.&lt;/p&gt;&#xA;" OwnerUserId="14123" LastEditorUserId="14123" LastEditDate="2021-06-15T09:23:50.650" LastActivityDate="2021-06-15T09:23:50.650" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22392" PostTypeId="1" CreationDate="2021-06-15T03:55:12.610" Score="1" ViewCount="64" Body="&lt;p&gt;Let's assume, humanity can decide to care more about the survival of our species, our duty to our descendants, than getting rich now. How long would it reasonably take to get to net-zero carbon emissions? How much longer with the planet continue to heat? Looking ahead 30, 50, or 100 years, what will the climate be in this best realistic-case scenario?&lt;/p&gt;&#xA;" OwnerUserId="22778" LastActivityDate="2021-06-15T03:55:12.610" Title="Best realistic-case scenario, what does our climate look like in 30 years...50 years...a 100 years?" Tags="|climate-change|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22393" PostTypeId="1" CreationDate="2021-06-15T04:36:28.640" Score="6" ViewCount="296" Body="&lt;p&gt;I have seen news reports saying that in recent years many more scientists think that humans first arrived in the Americas by boat, along coast of Alaska and Canada (before they were able to come through the Bering Strait land route). They would have done this ocean journey during the last ice age. Would this coast have been an ice cliff at that time? If so, such a long journey along such a coast must have been quite difficult. In other words, would early humans have had to follow along a coast that looked something like this picture below? Thank you in advance for any thoughts you can share on this.&lt;a href=&quot;https://i.stack.imgur.com/a8sE6.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/a8sE6.jpg&quot; alt=&quot;Iceberg&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22779" LastActivityDate="2023-08-11T17:32:47.740" Title="What did the water's edge look like on the Pacific coast of the Laurentide Ice Sheet?" Tags="|oceanography|glaciology|ice|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22395" PostTypeId="2" ParentId="22390" CreationDate="2021-06-15T16:09:11.047" Score="3" Body="&lt;p&gt;The answer, as is often the case for questions about optimums, depends on objectives and constraints.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;How accurately do you want to measure rainfall? The more gauges the more precision, but obviously at greater cost.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;How important is the spatial element, which in turn might depend on the objectives of monitoring? Is it more important to get accurate total volumes, or to identify variability and extremes?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Imagine two cases in the same region, with a hilly area, a hydroelectric dam and an agricultural lowland. The dam operators would want to accurately characterize inflow to their dam, while the farmers might want to measure dry season rainfall to schedule irrigation. A third agency might be satisfied with a single gauge that most closely represented a regional average. Their definitions of optimum would be rather different.&lt;/p&gt;&#xA;&lt;p&gt;With objectives determined the next question is where do you get data on existing rainfall and variability? Often it's the case that these questions of optimization are about rationalizing or refining existing networks. In this case you will have records from the existing network.&lt;/p&gt;&#xA;&lt;p&gt;While the detailed approach may vary, the basic principal is to compare the contribution, in terms of information, of each rain gauge to your quantitative objective. You can then eliminate the gauge that contributes the least information. This process can be repeated until a minimum network that meets the project objective is arrived at. Computationally refining this method to look at all possible combinations of subsamples is  usual. I.e. for a 10 gauge network you would look at all combinations of 9 gauges, then of 8 etc. until the objectives were met.&lt;/p&gt;&#xA;&lt;p&gt;A similar approach can be used to add gauges to a network, by looking at the correlations between adjacent rain gauges and siting gauges in areas of poor spatial correlation.&lt;/p&gt;&#xA;&lt;p&gt;«A New Approach for Optimizing Rain Gauge Networks: A Case Study in the Jinjiang Basin» by Wu &lt;em&gt;et al.&lt;/em&gt; is a good worked example of this process using geostatistics. Its reference list provides links to many other case studies.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Reference:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Wu, H.; Chen, Y.; Chen, X.; Liu, M.; Gao, L.; Deng, H. &lt;em&gt;Water&lt;/em&gt; &lt;strong&gt;2020&lt;/strong&gt;, &lt;em&gt;12&lt;/em&gt;, 2252; (&lt;a href=&quot;https://doi.org/10.3390/w12082252&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.3390/w12082252&lt;/a&gt;, open access).&lt;/p&gt;&#xA;" OwnerUserId="21672" LastEditorUserId="18990" LastEditDate="2021-06-16T04:29:27.067" LastActivityDate="2021-06-16T04:29:27.067" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22396" PostTypeId="1" CreationDate="2021-06-15T21:37:08.137" Score="2" ViewCount="53" Body="&lt;p&gt;I know lightning strikes ionise the air, but I'm looking into geology, specifically amethyst, and found that it gets its colour partially from trivalent iron, iron(III), Fe 3+, whatever you want to call it. Normally this happens by radiation during the formation of the amethyst, but I'm curious if a silica crystal with trace amounts of normal iron could be struck by lightning to ionise it and remove the additional electrons, thereby finalising the creation of amethyst, or am I missing some details about lightning and/or amethyst?&lt;/p&gt;&#xA;" OwnerUserId="22786" LastActivityDate="2021-06-17T03:07:28.160" Title="Can a lightning strike ionise the material it strikes?" Tags="|meteorology|geology|lightning|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22397" PostTypeId="1" AcceptedAnswerId="23539" CreationDate="2021-06-15T21:56:51.887" Score="4" ViewCount="156" Body="&lt;p&gt;By accident&lt;sup&gt;1&lt;/sup&gt; I ended up on the Bytes Daily page &lt;a href=&quot;http://bytesdaily.blogspot.com/2013/12/photographs-2013-part-1.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Photographs 2013, part 1&lt;/a&gt;. I saw an interesting image who's caption reads:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A white shelf cloud caps brownish dirt from a dust storm, or haboob, as it travels across the Indian Ocean near Onslow on the Western Australia coast in this handout image distributed by fishwrecked.com and taken January 9, 2013.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Haboob is described in Wikipedia as follows:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A haboob (Arabic: هَبوب‎, romanized: habūb, lit. 'blasting/drifting') is a type of intense dust storm carried on an atmospheric gravity current, also known as a weather front. &lt;strong&gt;Haboobs occur regularly in dry land area regions&lt;/strong&gt; throughout the world.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question(s):&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Is it rare or unusual for haboobs to travel across the Indian Ocean or other oceans?&lt;/li&gt;&#xA;&lt;li&gt;Is it rarer or more unusual still for shelf clouds to appear over them?&lt;/li&gt;&#xA;&lt;li&gt;What conditions are necessary to bring all of this about?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Video links from the Wikipedia article:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;YouTube: &lt;a href=&quot;https://www.youtube.com/watch?v=Ibpsxr71VVA&quot; rel=&quot;nofollow noreferrer&quot;&gt;Arizona Haboob!&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Vimeo: &lt;a href=&quot;https://vimeo.com/26045314&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Phoenix Haboob of July 5th, 2011&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt;I was doing a reverse image search looking for a larger size of the photo of Earth, Venus and Mars amidst the rings of Saturn when Cassini was in Saturn's shadow, and ended up on this page.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/br21t.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/br21t.jpg&quot; alt=&quot;Bytes Daily, 2013: A white shelf cloud caps brownish dirt from a dust storm, or haboob, as it travels across the Indian Ocean near Onslow on the Western Australia coast in this handout image distributed by fishwrecked.com and taken January 9, 2013.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2021-07-26T10:21:21.007" LastActivityDate="2022-02-16T15:19:35.047" Title="Is it unusual to see haboobs travel over the Indian Ocean with shelf clouds on top? What conditions can bring all of this about?" Tags="|clouds|atmospheric-dust|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22398" PostTypeId="2" ParentId="22390" CreationDate="2021-06-15T22:38:55.230" Score="1" Body="&lt;p&gt;Rainfall varies according to a lot of different factors, which include the location of mountains and hills, bodies of water, and vegetation.&lt;/p&gt;&#xA;&lt;p&gt;One approach is to collect data interactively with the environment. To do that keep placing rain gauges. If they are reading the same, separate them. So, by trial and error you determine a good distribution.&lt;/p&gt;&#xA;" OwnerUserId="2491" LastActivityDate="2021-06-15T22:38:55.230" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22399" PostTypeId="2" ParentId="22387" CreationDate="2021-06-16T01:01:05.100" Score="3" Body="&lt;p&gt;These look to be &lt;a href=&quot;https://en.wikipedia.org/wiki/Thermal&quot; rel=&quot;nofollow noreferrer&quot;&gt;Thermals &lt;/a&gt; to me . They form as a result of strong day time heating and vertical ascent in the lowest part of the planetary boundary layer. It's not clear what time of day the satellite image is but if it were around after 12 noon then that appears like cumulus clouds that have formed as a result of day time heating.&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastActivityDate="2021-06-16T01:01:05.100" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22400" PostTypeId="1" CreationDate="2021-06-16T12:32:18.227" Score="4" ViewCount="75" Body="&lt;p&gt;I came across several visual representation of the 1x5x9 pattern defined for block precedence computation in the ultimate pit limit problem. But I can't seem to understand fully how it is computed. I plan to code an algorithm for this pattern defined by Gilbert (1966). I already coded the 1x5 and 1x9 patterns suggested by Lerchs &amp;amp; Grossman.&lt;/p&gt;&#xA;&lt;p&gt;From the different papers that I found online, I sometimes see different visual representation of this specific 1x5x9 pattern. The first one that misleads me comes from the &lt;em&gt;&lt;a href=&quot;https://actamont.tuke.sk/pdf/2015/n4/1gilani.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;A new heuristic non-linear approach for modeling the variable slope angles in open pit mine planning algorithms (Seyed-Omid Gilani and Javad Sattarvand)&lt;/a&gt;&lt;/em&gt; research paper.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xsl6Q.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xsl6Q.png&quot; alt=&quot;1x5x9 pattern from Gilani &amp;amp; Sattarvand&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;And the second one, which is different from the previous one, but seems rather strange to me comes from the &lt;em&gt;&lt;a href=&quot;https://core.ac.uk/display/9554758&quot; rel=&quot;nofollow noreferrer&quot;&gt;Computer-Aided Optimal Open Pit Design With Variable Slope Angles (Reza Khalokakaie)&lt;/a&gt;&lt;/em&gt; research paper.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6TRui.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6TRui.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;From what I understand, this 1x5x9 precedence pattern is an alternated version of the 1x5 (for odd levels) and 1x9 (for even levels).&lt;/p&gt;&#xA;&lt;p&gt;Which one seems to be the perfectly defined one ?&lt;/p&gt;&#xA;" OwnerUserId="22790" LastEditorUserId="22790" LastEditDate="2021-06-16T22:30:06.837" LastActivityDate="2021-06-16T22:30:06.837" Title="Understanding 1x5x9 pattern for block precedence algorithm in open pit mining" Tags="|models|mining|grid-spacing|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22401" PostTypeId="1" CreationDate="2021-06-16T17:52:16.907" Score="1" ViewCount="13" Body="&lt;p&gt;I am not a geoscientist (I do computer graphics), however I am trying to render some geospatial data encoded as a WKT file.&lt;/p&gt;&#xA;&lt;p&gt;I have a &lt;code&gt;POLYGON&lt;/code&gt; with 2 coordinates per point, which seems to be representing latitude and longitude values (this is a guess on my end).&lt;/p&gt;&#xA;&lt;p&gt;I use spherical coordinates to map these points onto euclidean (x,y,z) points for rendering.&lt;/p&gt;&#xA;&lt;p&gt;The first problem I am having is, I am calculating latitude as an angle from the z axis (which matches the north pole) and latitude from the x axis (which seems to intersect with Greenwich meridian).&lt;/p&gt;&#xA;&lt;p&gt;To my understanding this should guarantee correct positioning, alas what I get is a very misplaced Canada. Moreover, even when I manage to place the border on the correct region, it is clear the border outline is highly deformed with regard to the earth sphere.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AFC0x.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AFC0x.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is the projection formula I am using to project the border:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;Eigen::Vector3d SphericalCoordinatesToEuclidean(const Eigen::Vector2d&amp;amp; point)&#xA;{&#xA;    const double longitude = (point.y()) * 2.f * M_PI / 360.f;&#xA;    const double latitude = (point.x()) * 2.f * M_PI / 360.f;&#xA;&#xA;    return {&#xA;        sin(latitude) * sin(longitude), sin(latitude) * cos(longitude), cos(latitude)};&#xA;}&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;The full data set is gigantic, this is just the section comprising the canadian border (every 2 values seem to be a point):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://gist.github.com/Makogan/1aec1ea701ae3c8cb3653506bc9d8873&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://gist.github.com/Makogan/1aec1ea701ae3c8cb3653506bc9d8873&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22792" LastActivityDate="2021-06-16T17:52:16.907" Title="Reading WKT data results in border deformations" Tags="|data-formats|projection|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22404" PostTypeId="2" ParentId="22396" CreationDate="2021-06-17T03:07:28.160" Score="2" Body="&lt;p&gt;There are &lt;a href=&quot;https://en.wikipedia.org/wiki/Fulgurite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fulgurites&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Fulgurites are formed when lightning strikes the ground, fusing and vitrifying mineral grains.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2021-06-17T03:07:28.160" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22405" PostTypeId="2" ParentId="22393" CreationDate="2021-06-17T03:27:16.887" Score="1" Body="&lt;p&gt;West of the Continental Divide it is the Cordilleran ice sheet.&lt;br /&gt;&#xA;I think the blue line &lt;a href=&quot;https://www.nature.com/articles/s41467-020-15579-0/figures/1&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; would have been ice shelves where it is in deep water. It also shows some ice-free land (note, sea level was 125 m lower).&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="2470" LastEditDate="2021-06-17T05:00:12.473" LastActivityDate="2021-06-17T05:00:12.473" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22406" PostTypeId="1" CreationDate="2021-06-17T07:39:43.933" Score="5" ViewCount="810" Body="&lt;p&gt;Why does some part of the ocean floor look so scratchy?&lt;/p&gt;&#xA;&lt;p&gt;If you look at Google Earth image of the Indian ocean floor, especially the area south-west of Sumatra, it looks like some cosmic beast scratched it with its sharp claws. The same thing can be seen near the Hawaiian islands. I know it has something to do with tectonic movements and stuff, but I don't know for sure.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KvubZm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KvubZm.jpg&quot; alt=&quot;The sea floor around Cocos Islands&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/b/b9/NinetyEastRidge.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;The sea floor around Cocos Islands&lt;/a&gt;&lt;br/&gt;&#xA;So what is the explanation for this?!&lt;/p&gt;&#xA;" OwnerUserId="22796" LastEditorUserId="18088" LastEditDate="2022-02-26T20:43:18.903" LastActivityDate="2022-02-26T20:43:18.903" Title="Why does the ocean floor look so scratchy?" Tags="|oceanography|plate-tectonics|ocean-ridge|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="22407" PostTypeId="2" ParentId="22406" CreationDate="2021-06-17T09:05:25.453" Score="2" Body="&lt;p&gt;If I am understanding the question correctly those straight lines may not actually be lines, they may be strips or bands and they are bands that are not actually there. The bands are a result of combining the available sea floor profile data into a single map and are bands of sea bottom that follow the course of ships that do such mapping - thus the straight part - at higher resolution than the areas around them. Zoom in close and the different resolutions within and outside those bands become easier to identify.&lt;/p&gt;&#xA;&lt;p&gt;Or else it is the patterning of ocean bottom accompanying the boundaries of tectonic plates that have histories of diverging. I'm not sure why such patterns emerge; someone better informed may be able to answer better.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="18145" LastEditDate="2021-06-17T09:16:36.527" LastActivityDate="2021-06-17T09:16:36.527" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22408" PostTypeId="1" CreationDate="2021-06-17T13:05:35.813" Score="1" ViewCount="34" Body="&lt;p&gt;The Santa Ana winds flow down mountain slopes, growing ever hotter as they descend.  To my amazement, &lt;a href=&quot;https://en.wikipedia.org/wiki/Santa_Ana_winds&quot; rel=&quot;nofollow noreferrer&quot;&gt;popular explanations&lt;/a&gt; of these winds even attribute them to specific mountain passes.  Suppose for a moment that a large government subsidy pumped as much free desalinated water all the way up from the coast up to these passes and the nearby slopes as farmers could spray on pistachios, almonds, tomatoes ... any water intensive crop they can think of to plant there.  Would the amount of water vapor released this way be sufficient to cause the winds to rise instead of falling, causing air to remain stagnant or come inward from the California coast rather than going out as Santa Ana wind?&lt;/p&gt;&#xA;" OwnerUserId="22797" LastActivityDate="2021-06-17T13:05:35.813" Title="Could irrigation stop the Santa Ana winds?" Tags="|wind|water-vapour|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22410" PostTypeId="2" ParentId="20956" CreationDate="2021-06-17T15:45:19.927" Score="9" Body="&lt;p&gt;Somalia's dryness despite it's proximity to the equator (which should provide ample opportunities for year round rainfall) has perplexed most meteorologists. In this following answer we will try to explore some of the reasons behind this paradox.&lt;/p&gt;&#xA;&lt;p&gt;There are three major airflows - the Congo Air(Part of the Congo Air Boundary ) that brings in westerly and south westerly flow to the region and the north east monsoon and the south east monsoon. The issue with both of the monsoons is that the flow is parallel to the shore.&lt;/p&gt;&#xA;&lt;p&gt;A plot of the climatology of the June- September monsoon(JJAS) shows the winds 850 winds flow parallel to the shore. The winds encounter what is known as a friction differential i.e. the friction over the land is greater than the friction of the ocean surface. Presuming the low pressure is over the land(during the day due to solar radiation) the resulting frictional difference causes the winds to diverge over the coastal areas. For details on this reference (4) explains the math behind it.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kO7Pw.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kO7Pw.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The following plot shows the 850 hPa streamfunction over East Africa and is a climatology. Positive values of the streamfunction in the northern hemisphere correspond to low level divergence(enhances subsidence) and negative values to low level wind convergence(enhances ascent). This low level divergence induces subsidence of the air and prevents precipitation.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ihjQV.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ihjQV.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The climatology of the lower level stream function is shown for the whole year but it does not change much if you take it for any of the two seasons (JJAS) or (NDJF) individually. There is only lower level wind divergence.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lFwrV.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lFwrV.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The contour lines are the isobars.&lt;/p&gt;&#xA;&lt;p&gt;I have made my version of Fig 2.29  in (3)(due to copyright) that shows off shore winds parallel to the shore and winds diverging onshore due to the frictional differential. This phenomenon of winds diverging at the coast is not unique to Sonalia but is present everwhere you have coastal deserts and winds flowing parallel to the shore. If the winds did approach the coastline either perpendicular or at an angle then there would be greater low level wind convergence (850 hPa level)as the air would &amp;quot;pile up&amp;quot; at the shore  promoting ascent of the air and precipitation. That would be reflected in the climatological 850 hPa wind  streamfunction values.&lt;/p&gt;&#xA;&lt;p&gt;The same off shore south easterly winds cause upwelling along the coast and bring in cooler SSTs. The phenomenon is reversed during the North East Monsoon (Oct - March) the NE winds flow parallel to the shore.&lt;/p&gt;&#xA;&lt;p&gt;Please note that the lower level wind divergence shown here is for large scale winds and Somalia may indeed get some rains due to a mesoscale phenomenon known as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Sea_breeze&quot; rel=&quot;noreferrer&quot;&gt;Sea Breeze front&lt;/a&gt; but that depends on whether the coastline is convex or concave over a short distance.&lt;/p&gt;&#xA;&lt;p&gt;Somalia does get some rains due to the westerly flow due to some  combination of mid latitude disturbances and tropical influences and these are known as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Somali_Flash_Floods&quot; rel=&quot;noreferrer&quot;&gt;Gu rains&lt;/a&gt;. The Ethopian  Highlands and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Rift_Valley&quot; rel=&quot;noreferrer&quot;&gt;East African Rift Valley&lt;/a&gt; act as a barrier for the westerly moist laden flow (and the Somalian region is the leeward region) but some amount of moisture does slip by through the transition period in between the two seasons.&lt;/p&gt;&#xA;&lt;p&gt;Finally reference (2) also talks of the Pacific Warm Pool extending into t he Indian Ocean and the Walker Cell due to the Indian Monsoon westerlies rising over the East Indian Ocean and causing subsidence over the Arabian Sea.&lt;/p&gt;&#xA;&lt;p&gt;References :&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Nicholson, S. E. (2011), Dryland Climatology, 516 pp., Cambridge Univ. Press, New York.&lt;a href=&quot;https://www.cambridge.org/core/books/dryland-climatology/AD650508A319ABA023FF3132D958F9F5&quot; rel=&quot;noreferrer&quot;&gt;Dryland Climatology&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Nicholson, S. E. (2017), Climate and climatic variability of rainfall over&#xA;eastern Africa, Rev. Geophys., 55,590–635,&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2016RG000544&quot; rel=&quot;noreferrer&quot;&gt;East African climate and rainfall &lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Warner, T. T., 2004: Desert Meteorology. Cambridge University Press,&#xA;Cambridge, 595 pp&#xA;&lt;a href=&quot;https://www.cambridge.org/core/books/desert-meteorology/830636E147078337D24957845F6A6855&quot; rel=&quot;noreferrer&quot;&gt;Desert Meteorology&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Bryson, R. A., and P. M. Kuhn, 1961: Stress-differential induced divergence with application to littoral precipitation. Erdkunde, 15,&#xA;287–294.&lt;a href=&quot;https://www.jstor.org/stable/25636783&quot; rel=&quot;noreferrer&quot;&gt;Friction Induced Differential&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2021-06-17T16:19:23.173" LastActivityDate="2021-06-17T16:19:23.173" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22411" PostTypeId="1" AcceptedAnswerId="22413" CreationDate="2021-06-17T19:33:47.683" Score="1" ViewCount="75" Body="&lt;p&gt;We have:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Reached a population of 8 billion&lt;/li&gt;&#xA;&lt;li&gt;Doubled greenhouse gases&lt;/li&gt;&#xA;&lt;li&gt;Extincted numerous species&lt;/li&gt;&#xA;&lt;li&gt;Filled the ocean floor with waste&lt;/li&gt;&#xA;&lt;li&gt;Contaminated the soil with petroleum derivatives&lt;/li&gt;&#xA;&lt;li&gt;Contaminated aquifers&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Could we be considered a plague? Do we have solution?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastActivityDate="2021-06-17T23:37:08.497" Title="Are humans a plague?" Tags="|ecology|" AnswerCount="1" CommentCount="3" ClosedDate="2021-06-18T08:18:02.520" ContentLicense="CC BY-SA 4.0" />
  <row Id="22412" PostTypeId="2" ParentId="21274" CreationDate="2021-06-17T20:06:53.797" Score="2" Body="&lt;p&gt;Like many of the other questions I answer on Earth Science SE, the answer is complicated. Based on the &lt;a href=&quot;http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/fw/geos.rxml&quot; rel=&quot;nofollow noreferrer&quot;&gt;principle of geostrophy&lt;/a&gt;, the Coriolis force will point to the right of the wind vector in the northern hemisphere (left in the southern hemisphere).&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Can you &lt;em&gt;validate&lt;/em&gt; the Coriolis force based on the wind rose?&lt;/strong&gt; No. You would need multiple simultaneous wind observations over a wide observation space. You can see this in weather maps that show wind direction. It becomes easier to see the Coriolis effect on upper air maps, as they aren't affect by the surface. It is also easier to see further from the equator, where the Coriolis is zero. &lt;a href=&quot;https://earth.nullschool.net/#current/wind/isobaric/500hPa/orthographic=-58.35,45.51,734&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth NullSchool has nifty maps that show worldwide winds&lt;/a&gt; that can help you see the Coriolis effect (the color is the mean sea level pressure):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dOVxg.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dOVxg.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ENs84.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ENs84.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;In your wind rose, you can approximate the Coriolis effect though, by turning it sideways.&lt;/p&gt;&#xA;&lt;p&gt;The Coriolis effect can be experienced beyond the realm of meteorology (and I am not referring to the toilet-bowl fallacy). Long before Gaspard Coriolis lived, &lt;a href=&quot;https://en.wikipedia.org/wiki/Giovanni_Battista_Riccioli#The_%22coriolis_effect%22_argument&quot; rel=&quot;nofollow noreferrer&quot;&gt;it was recognized that cannonballs were deflected by the Earth's rotation&lt;/a&gt;, though it did have some inaccuracies.&lt;/p&gt;&#xA;&lt;p&gt;One question I anticipate that I anticipate you might have is &amp;quot;How far would a something (wind or a cannonball) have to travel before the Coriolis effect would have a meaningful effect?&amp;quot; Projectiles are, in my opinion, the easiest way to show that this is a real thing. This &amp;quot;acceleration&amp;quot; is approximately &lt;span class=&quot;math-container&quot;&gt;$a_{cor}=fv$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$f$&lt;/span&gt; is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Coriolis_frequency&quot; rel=&quot;nofollow noreferrer&quot;&gt;latitudinally dependent Coriolis parameter&lt;/a&gt;. and &lt;span class=&quot;math-container&quot;&gt;$v$&lt;/span&gt; is the speed. &lt;a href=&quot;https://en.wikipedia.org/wiki/Coriolis_force#Ballistic_trajectories&quot; rel=&quot;nofollow noreferrer&quot;&gt;You can see how this impacts ballistics through this Wikipedia entry&lt;/a&gt;. Given various assumptions, like a constant latitude, ignoring drag, and ignoring the loss of forward momentum from the perpendicular acceleration, the distance one would be off  after firing a projectile would be: &lt;span class=&quot;math-container&quot;&gt;$$\Delta y = 2 \Omega \sin(\phi) (\Delta x)^2 u_0^{-1} $$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$\Omega$&lt;/span&gt; is the  angular velocity of the earth, &lt;span class=&quot;math-container&quot;&gt;$\phi$&lt;/span&gt; is the latitude, and &lt;span class=&quot;math-container&quot;&gt;$u$&lt;/span&gt; is the speed, and &lt;span class=&quot;math-container&quot;&gt;$\Delta x$&lt;/span&gt; is the distance to the target. So at say 45 degrees north and going 5 meters per second over a 100 meter distance, you would be off by 0.2 meters, &lt;a href=&quot;http://academickids.com/encyclopedia/index.php/Paris_Gun&quot; rel=&quot;nofollow noreferrer&quot;&gt;but if you are the Paris gun with a horizontal velocity of 1009.7 m/s, trying to bombard the city 120 km away at a latitude of 49 degrees north, you'll be 1.3 km off if you don't account for the Coriolis effect&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;And because I know I will get someone who wants me to show my work for the previous equation here it is: &lt;span class=&quot;math-container&quot;&gt;$$\frac{d\vec{v}}{dt}=-f\hat{k}\times\vec{v}$$&lt;/span&gt;. If we consider the initial conditions &lt;span class=&quot;math-container&quot;&gt;$\vec{v}(t=0)=u(t=0)\hat{i}+v(t=0)\hat{j}=u_0\hat{i}+0\hat{j}$&lt;/span&gt;, then we have the system &lt;span class=&quot;math-container&quot;&gt;$$\frac{du}{dt}=fv$$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$$\frac{dv}{dt}=-fu$$&lt;/span&gt;. Since I made the assumption that momentum along the trajectory is not altered by the Coriolis force, the system reduces to  &lt;span class=&quot;math-container&quot;&gt;$$\frac{du}{dt}=0$$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$$\frac{dv}{dt}=-fu$$&lt;/span&gt;. If we think that wind is the changing coordinates (&lt;span class=&quot;math-container&quot;&gt;$u=\frac{dx}{dt}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$v=\frac{dy}{dt}$&lt;/span&gt;), then the system can be represented as &lt;span class=&quot;math-container&quot;&gt;$$\frac{d^2x}{dt^2}=0$$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$$\frac{d^2y}{dt^2}=-fu=-fu_0$$&lt;/span&gt;. Therefore &lt;span class=&quot;math-container&quot;&gt;$$\Delta y= fu_0t^2$$&lt;/span&gt;. And since the projectile must travel distance &lt;span class=&quot;math-container&quot;&gt;$\Delta x$&lt;/span&gt; at velocity &lt;span class=&quot;math-container&quot;&gt;$u_0$&lt;/span&gt;, then &lt;span class=&quot;math-container&quot;&gt;$$t=\frac{\Delta x}{u_0}$$&lt;/span&gt; which makes  &lt;span class=&quot;math-container&quot;&gt;$$\Delta y = 2 \Omega \sin(\phi) (\Delta x)^2 u_0^{-1} $$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-06-17T20:06:53.797" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22413" PostTypeId="2" ParentId="22411" CreationDate="2021-06-17T23:37:08.497" Score="2" Body="&lt;p&gt;In some (Or most ways) Yes. Pollution, Poaching, littering  and etc Has hurt Biodiversity, lots of Animals who went extinct because of Humans wouldnt be familiar to an Average person, &lt;a href=&quot;https://alansfactoryoutlet.com/36-extinct-animals-lost-to-history-due-to-human-activity/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this link&lt;/a&gt; provides some insight into the animals that went extinct.&lt;/p&gt;&#xA;&lt;p&gt;Humans are the most adaptable Animals in the world, this degree of Adaptability causing tremendous Population growth, Urbanization  and etc. &lt;a href=&quot;https://support.worldwildlife.org/site/Donation2?df_id=14597&amp;amp;14597.donation=form1&amp;amp;s_src=AWE1800OQ18695A01430RX&amp;amp;msclkid=0003702630561c979cc710edec6f9e63&amp;amp;utm_source=bing&amp;amp;utm_medium=cpc&amp;amp;utm_campaign=Brand&amp;amp;utm_term=wwf.com&amp;amp;utm_content=WorldWildlife.Org&quot; rel=&quot;nofollow noreferrer&quot;&gt;However there is a way to solve this&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Denial and Politics has kept us doing this in the recent past, but yes, there is a way to fix this.&lt;/p&gt;&#xA;" OwnerUserId="21926" LastActivityDate="2021-06-17T23:37:08.497" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22414" PostTypeId="1" CreationDate="2021-06-18T00:12:26.160" Score="5" ViewCount="53" Body="&lt;p&gt;From my understanding, the formation of ores can be reduced to a simple three-step process of the removal of minerals from a source via some mechanism, the transportation of these minerals, and finally, the deposition of the mineral into some concentrated form (ore) that is able to be extracted.&lt;/p&gt;&#xA;&lt;p&gt;My question is (and I know this sounds ridiculous) but &lt;strong&gt;is it currently or theoretically possible to recreate the conditions under which ores are formed naturally, catalyze these reactions in some way (i.e. reduce the time span from potentially hundreds of millions of years), and extract a usable product?&lt;/strong&gt; To me, the only barrier (other than the potential physical impossibilities of which I am sure I will be informed of briefly) is some engineering.&lt;/p&gt;&#xA;&lt;p&gt;Is this done in some computational or experimental way by researchers who observe ore genesis? Or in other disciplines in geology who observe processes that occur over large intervals of time?&lt;/p&gt;&#xA;&lt;p&gt;I know that this (speeding up natural reactions) is sort of similar to the principle that salt brines operate under to create Lithium. Another example I suppose is carbon sequestration technology, but I am not too familiar with that.&lt;/p&gt;&#xA;" OwnerUserId="17398" LastActivityDate="2021-06-18T00:12:26.160" Title="Artifical Ore Genesis?" Tags="|geology|geochemistry|mineralogy|geomorphology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22415" PostTypeId="1" CreationDate="2021-06-18T01:33:36.203" Score="2" ViewCount="117" Body="&lt;p&gt;this is my first time posting in Earth Science, please be gentle to me.&lt;/p&gt;&#xA;&lt;p&gt;I am Science Enthusiast, though numbers are my enemies for now so I can't come up with formulas or any form of calculations. However, I do understand some of the facts and some laws became my common sense, that leads to this question.&lt;/p&gt;&#xA;&lt;p&gt;With our current technology, I believe we have the power to make devices that sends water into glaciers or ice.&#xA;In my opinion, those water will become ice, rebuilding cracks of glaciers (if any?), and reducing sea level at the same time.&lt;/p&gt;&#xA;&lt;p&gt;My question is, is this a good idea? will it helps global warming/climate change? or will it worsen the situation?&lt;/p&gt;&#xA;&lt;p&gt;I also thought of creating artificial rain via artificial clouds but I don't think it is a good idea.&lt;/p&gt;&#xA;&lt;p&gt;PS.&lt;/p&gt;&#xA;&lt;p&gt;I don't know much of this stuff, but I'm kinda desperate since Australia (and other countries) might be uninhabitable completely within this century.&lt;/p&gt;&#xA;" OwnerUserId="18655" LastEditorUserId="18081" LastEditDate="2021-06-18T10:21:46.623" LastActivityDate="2021-06-18T11:10:18.590" Title="If we send ocean waters into glacier of north pole/south pole to reduce sea level, will it help global warming?" Tags="|climate-change|sea-level|geoengineering|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22416" PostTypeId="1" CreationDate="2021-06-18T03:24:30.060" Score="6" ViewCount="329" Body="&lt;p&gt;Do CO&lt;sub&gt;2&lt;/sub&gt; hydrates exist in nature? If so, how much carbon could they contain?&lt;/p&gt;&#xA;" OwnerUserId="22045" LastEditorUserId="22648" LastEditDate="2021-06-23T03:17:31.183" LastActivityDate="2021-07-25T14:17:58.360" Title="Do carbon dioxide hydrates exist in nature?" Tags="|geology|geochemistry|co2|clathrates|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22417" PostTypeId="2" ParentId="22415" CreationDate="2021-06-18T11:10:18.590" Score="1" Body="&lt;p&gt;The problem faced by so many geo-engineering approaches is that the scale of the problem is so great. We are losing approximately 300 cubic kilometers of  ice  just in the Artic each year &lt;a href=&quot;http://psc.apl.uw.edu/wordpress/wp-content/uploads/schweiger/ice_volume/BPIOMASIceVolumeAnomalyCurrentV2.1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;(trends in Artic ice volume&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;300 cubic kilometres of ice is  3 x 10&lt;span class=&quot;math-container&quot;&gt;$^{11}$&lt;/span&gt; metric tons of water. Lets imagine a series of pumps that are placed at the North pole and raise sea water from under the ice. We will raise the water 10 metres to spread it over the ice. It takes 100 Mega Joules to raise a metric ton of water that height. So we need 3 x 10&lt;span class=&quot;math-container&quot;&gt;$^{13}$&lt;/span&gt; Mega Joules of energy to raise enough water to compensate for global warming induced ice loss.&lt;/p&gt;&#xA;&lt;p&gt;Allowing for pump efficiencies etc. we would need about 1.5 x 10&lt;span class=&quot;math-container&quot;&gt;$^{13}$&lt;/span&gt; Kilowatt Hours of electricity. This is 1.5 x 10&lt;span class=&quot;math-container&quot;&gt;$^{10}$&lt;/span&gt; Megawatt Hours. Current global annual electricity generation is about 2 x 10&lt;span class=&quot;math-container&quot;&gt;$^{10}$&lt;/span&gt; Megawatt Hours! So we would need to more or less double our current global energy production to address just a part of the problem, and this ignores both the engineering practicalities and the issues of whether pumped sea water would actually freeze and 'restore' the polar ice.&lt;/p&gt;&#xA;&lt;p&gt;And of course adding to sea ice wouldn't affect sea level rise - so actually pumping would have to be to much greater heights and use much more energy to build ice caps on land.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2021-06-18T11:10:18.590" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22418" PostTypeId="1" CreationDate="2021-06-18T11:39:57.087" Score="1" ViewCount="868" Body="&lt;p&gt;Deepest as in has had the most sediment above it. Obviously it has to be exposed to be found but it's still considered deep if its previously been covered by sediment. I should mention im not looking for cases where they've drilled holes deep in the earth and found microorganisms I mean situations where the fossil was once on the surface then got covered by sediment.&lt;/p&gt;&#xA;" OwnerUserId="19121" LastActivityDate="2021-06-18T11:39:57.087" Title="What is deepest fossil we have found?" Tags="|fossils|stratigraphy|geologic-layers|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22419" PostTypeId="2" ParentId="17530" CreationDate="2021-06-19T02:55:48.593" Score="1" Body="&lt;p&gt;The definition of a solute that is capable of dissolving in a solvent is that the force of attraction between the atoms in a solute are not strong enough to keep the molecule together when surrounded by the many negative and positive partial charges that make up the solvent. I don’t know exactly how many ion-dipole bonds Cl- and Na+ form with H(partial charge δ+) and O(partial charge δ-), respectively, but there are enough ion dipole bonds between these atoms that the bond between Na and Cl isn’t strong enough to keep it in solid form so it dissolves into its ions and forms ion dipole bonds with the water. At the bottom of the ocean these ion-dipole bonds are still in effect (I’m unsure how the pressure do to the weight of the water above it effects these ion dipole bonds however) but the density of the ocean water, as illustrated in this diagram I found on google, does appear to increase in density with depth but after 1000 m it seems that the salt water can’t be compressed anymore to increase its density. &lt;img src=&quot;https://i.stack.imgur.com/QjCpX.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;" OwnerUserId="22809" LastActivityDate="2021-06-19T02:55:48.593" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22420" PostTypeId="1" CreationDate="2021-06-19T05:42:16.273" Score="2" ViewCount="736" Body="&lt;p&gt;On Google Earth I noticed many straight lines. While looking for answers for their existence, I came across &lt;a href=&quot;https://www.quora.com/What-are-the-straight-lines-we-see-on-the-ocean-floor-in-Google-Earth-caused-by/answer/Kelly-Kochanski/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this Quora answer&lt;/a&gt;, which provided a good response for why there are converging lines to certain locations, like the ones marked in the image below in pink on Tahiti.&lt;/p&gt;&#xA;&lt;p&gt;The answer also mentioned the parallel lines (pink in that answer's image, yellow in mine). It says that these are not mapping anomalies, but natural features, which are created perpendicular to seafloor spreading ridges. If that is true what creates these parallel lines?&lt;/p&gt;&#xA;&lt;p&gt;It surprises me that they are thousands of kilometres long and almost parallel.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Bap3i.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Bap3i.jpg&quot; alt=&quot;Lines found on Google Earth satellite images&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22649" LastEditorUserId="22648" LastEditDate="2021-06-20T15:29:38.720" LastActivityDate="2021-06-20T17:33:40.870" Title="What are the parallel horizontal lines on Google's satellite images?" Tags="|topography|ocean-ridge|sea-floor|" AnswerCount="1" CommentCount="2" ClosedDate="2021-06-23T19:21:13.397" ContentLicense="CC BY-SA 4.0" />
  <row Id="22421" PostTypeId="1" AcceptedAnswerId="22424" CreationDate="2021-06-19T19:33:26.070" Score="4" ViewCount="139" Body="&lt;p&gt;My understanding of climate change is that a large increase in human-caused CO&lt;sub&gt;2&lt;/sub&gt; emissions is likely to lead to large change in the Earth's climate through a global warming effect. Scientific consensus appears to me to be that if we make similarly large reductions in CO&lt;sub&gt;2&lt;/sub&gt; emissions, we can reduce the magnitude of the consequent warming.&lt;/p&gt;&#xA;&lt;p&gt;I also understand the climate to have many non-linear mechanisms whereby the link between emission and warming isn't at all straightforward - and so we can only talk about broad averages and so forth, rather than make specific weather predictions.&lt;/p&gt;&#xA;&lt;p&gt;So is it always true that a reduction in emissions will - on average - cause a reduction in the global warming effect, however small?  Or does the existence of &lt;a href=&quot;https://en.wikipedia.org/wiki/Tipping_points_in_the_climate_system&quot; rel=&quot;nofollow noreferrer&quot;&gt;tipping points&lt;/a&gt; or any other factor mean that only large reductions can make a difference now and any lesser reduction will be pointless?&lt;/p&gt;&#xA;&lt;p&gt;My intuition says that smaller cuts in emissions should still be preferred to no cuts at all, as I imagine that they would reduce the peak warming and/or delay the peak for longer and/or reduce the eventual recovery time. Perhaps not by as much as we might prefer, but still better than nothing. But perhaps my intuition is off.&lt;/p&gt;&#xA;" OwnerUserId="22814" LastEditorUserId="22648" LastEditDate="2021-06-21T07:49:53.107" LastActivityDate="2021-06-21T07:49:53.107" Title="Are small reductions in CO2 emissions better than no reductions, in terms of mitigating climate change?" Tags="|climate-change|co2|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22422" PostTypeId="1" CreationDate="2021-06-19T19:57:09.477" Score="4" ViewCount="86" Body="&lt;p&gt;I am working on WRF_GHG, I would like to run WRF-VPRM and I've put the vprm input files in WRF folder(vprm_input_d01_2010-01-16_00:00:00,vprm_input_d01_2010-01-17_00:00:00).but when I run wrf(./wrf.exe) ,I can't have &lt;em&gt;EBIO_GEE&lt;/em&gt; and &lt;em&gt;EBIO_RES&lt;/em&gt; fluxes in my wrf-output files.I think maybe I compiled the model wrong, that is the reason that I can't have two of these parameters in my wrf_output files.&#xA;can you help me, please?&#xA;Thank you very much indeed&#xA;best regards&#xA;Sara&lt;/p&gt;&#xA;" OwnerUserId="18881" LastActivityDate="2021-10-23T12:27:51.897" Title="compile WRF-VPRM to have EBIO_GEE and EBIO_RES fluxes in your output" Tags="|wrf-chem|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22423" PostTypeId="1" CreationDate="2021-06-19T23:20:45.100" Score="2" ViewCount="51" Body="&lt;p&gt;I want to know how hard or strong typical speleothems are. For example, could an average man break off a small stalactite or soda straw? If they're very hard, how do they compare to bone?&lt;/p&gt;&#xA;" OwnerUserId="21105" LastActivityDate="2021-06-20T21:34:27.183" Title="How strong/hard are speleothems?" Tags="|geology|cavern|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22424" PostTypeId="2" ParentId="22421" CreationDate="2021-06-20T03:21:57.827" Score="9" Body="&lt;p&gt;Yes, because carbon emissions &lt;a href=&quot;https://en.wikipedia.org/wiki/Emissions_budget&quot; rel=&quot;noreferrer&quot;&gt;are like a budget&lt;/a&gt;. The Mercator Institute has one of the most commonly cited &lt;a href=&quot;https://www.mcc-berlin.net/en/research/co2-budget.html&quot; rel=&quot;noreferrer&quot;&gt;analyses of our carbon budget&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;the atmosphere can absorb, calculated from end-2017, no more than 420 gigatonnes (Gt) of CO&lt;sub&gt;2&lt;/sub&gt; if we are to stay below the 1.5°C threshold. Annual emissions of CO&lt;sub&gt;2&lt;/sub&gt; – from burning fossil fuels, industrial processes and land-use change – are estimated to be around 42 Gt per year, the equivalent of 1,332 tonnes per second. With emissions at a constant level, the budget would be expected to be used up in less than seven years from now. The budget for staying below the 2°C threshold, for its part, of approximately 1,170 Gt, would be exhausted in about 25 years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So, just like a household or business budget, small (but persistent) reductions in spending/emissions do make a difference in the long run.&lt;/p&gt;&#xA;" OwnerUserId="7741" LastActivityDate="2021-06-20T03:21:57.827" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22428" PostTypeId="1" AcceptedAnswerId="22432" CreationDate="2021-06-20T15:01:56.660" Score="8" ViewCount="279" Body="&lt;p&gt;What exactly is &amp;quot;Land-Use Change and Forestry&amp;quot; and why is it sometimes hugely positive (Indonesia) but sometimes hugely negative (China)? Isn't it supposed to be a type of source, not sink (you cut trees, you get more GHG)? See the data &lt;a href=&quot;https://www.climatewatchdata.org/data-explorer/historical-emissions&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="22632" LastEditorUserId="22632" LastEditDate="2022-10-17T22:12:42.850" LastActivityDate="2022-10-17T22:12:42.850" Title="What exactly is &quot;Land-Use Change and Forestry&quot;?" Tags="|climate-change|greenhouse-gases|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22429" PostTypeId="2" ParentId="22420" CreationDate="2021-06-20T17:33:40.870" Score="3" Body="&lt;p&gt;The yellow east-west trending lines (except possibly one) are &lt;a href=&quot;https://en.wikipedia.org/wiki/Transform_fault&quot; rel=&quot;nofollow noreferrer&quot;&gt;transcurrent fault&lt;/a&gt;s associated with mid-ocean ridges. They divide strips of ocean floor produced by segments of the ridge.&lt;/p&gt;&#xA;&lt;p&gt;A mid-ocean ridge is not a continuous line. Instead, it's a series of short segments offset from each other. Transform faults connect the offset spreading-center segments.&lt;/p&gt;&#xA;&lt;p&gt;In the section of fault between the two spreading segments, the strips of oceanic crust they produce are moving in opposite directions on different tectonic plates, but as the mid-ocean ridges make more oceanic crust over millions of years, the strips on the &amp;quot;same side&amp;quot; of the spreading center segments will come into contact with each other as part of the same plate. One strip's rock will be considerably older than on the strip next to it, and the line where they contact is a &amp;quot;transcurrent&amp;quot; fault that will last until that part of the plate is subducted. Some of these faults are more seismically active than others, due to the same stresses that caused the offsets in the first place.&lt;/p&gt;&#xA;&lt;p&gt;Look at this Google Earth screenshot of the northeast Pacific that I've marked up:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/MPena.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MPena.jpg&quot; alt=&quot;north pacific with faults highlighted&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Two of the lines you pointed out are highlighted in red. The spreading ridges are green and the transform faults are blue. This is an unusual circumstance because they are connected at one end by a long transform fault, the San Andreas Fault. When the North American Plate finished swallowing the Farallon Plate in this section 30 million years ago, the spreading centers of the East Pacific Rise adjusted themselves to the stresses along the SAF.&lt;/p&gt;&#xA;&lt;p&gt;Now, about the image and the one line that doesn't fiy. Google derives their seafloor map by combining several sources: Actual bathymetry from ship tracks (the dark streaks), gravity data (older seafloor is denser), maybe even a satellite radar map, and probably fills in the gaps with a computer model. The one line that's out of alignment is a ship track. You can tell by zooming in on it to spot a streak of higher-resolution image surrounded by fuzzier terrain:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/BJpm6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BJpm6.jpg&quot; alt=&quot;illustration of ship track&quot; /&gt;&lt;/a&gt;. When you zoom in on one of your lines, you still see the feature.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastActivityDate="2021-06-20T17:33:40.870" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22430" PostTypeId="2" ParentId="22423" CreationDate="2021-06-20T21:34:27.183" Score="2" Body="&lt;p&gt;The speleothems are made of calcite, so breaking one small stalactite is same as breaking one narrow &amp;quot;straw&amp;quot; of calcite. Calcite is not so strong, so it is pretty easy to break small stalactite. Bone is much much stronger than one stalactite. Of course, the big ones (1 meter diameter) are harder to break.&lt;/p&gt;&#xA;&lt;p&gt;I see that you asked this here because you don't want to try it in real life, and I approve that :)&lt;/p&gt;&#xA;" OwnerUserId="19122" LastActivityDate="2021-06-20T21:34:27.183" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22431" PostTypeId="1" CreationDate="2021-06-20T23:40:06.273" Score="4" ViewCount="45" Body="&lt;p&gt;I've noticed this during summers (lived here since birth). Sometimes there will be cloudless blue skies, other times when it gets warm there will be a layer of thin clouds, often with higher humidity levels and uncomfortably warm nights. I took a picture of what I mean on Friday.&lt;a href=&quot;https://i.stack.imgur.com/9VQvW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9VQvW.jpg&quot; alt=&quot;overcast&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;My guess is monsoonal flow that can't develop into thunderstorms due to high pressure aloft.&lt;/p&gt;&#xA;" OwnerUserId="6816" LastEditorUserId="6816" LastEditDate="2021-06-25T22:26:53.953" LastActivityDate="2021-06-25T22:26:53.953" Title="Why does the current warm spell in the Pacific Northwest include high, thin clouds?" Tags="|meteorology|weather-forecasting|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22432" PostTypeId="2" ParentId="22428" CreationDate="2021-06-21T06:32:42.123" Score="8" Body="&lt;p&gt;You are correct that normally you see a net positive value of GHGs from land use change.  However, if forests are grown or revegetated, it is considered a sink (and negative GHG value).  &lt;a href=&quot;https://www.researchgate.net/publication/309654565_Carbon_emissions_from_land-use_change_and_management_in_China_between_1990_and_2010&quot; rel=&quot;noreferrer&quot;&gt;This paper&lt;/a&gt; says that China has undergone a net increase in forest.&lt;br /&gt;&#xA;The results sections says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The land-use data derived from Landsat Thematic Mapper (TM) imagery from 1990 to 2010 were used to estimate the spatiotemporal dynamics of land-use and carbon storage change.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Between 1990 and 2010, China experienced a net increase in forestland, farmland, urban land, and other land (sandy land, gobi, saline-alkali land, swampland, bareland, rock and gravel, and other unused land; table S1). The magnitudes of these increases were 1.52 × 106ha (+0.7%), 1.48 × 106ha (+0.8%),6.87 × 106ha (+43.0%), and 11.74 × 106ha (+5.8%), respectively.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Over the last few decades, the Chinese government developed a number of afforestation programs to revert historically forested areas that had previously been converted into farmland back to forest. Programs, such as the Slope Land Conversion Project and the Natural Forest Protection Project, were responsible for the increases in the area of forest in most regions, except Northeast and Northwest China.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2021-06-21T06:38:02.800" LastActivityDate="2021-06-21T06:38:02.800" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22434" PostTypeId="1" CreationDate="2021-06-21T14:11:31.257" Score="3" ViewCount="24" Body="&lt;p&gt;I want to use the foliage to create compost for my farm.&#xA;What are the maximum foliage shedding tropical evergreen trees ?&lt;/p&gt;&#xA;" OwnerUserId="22831" LastActivityDate="2021-06-21T14:11:31.257" Title="Which tropical evergreen trees shed the maximum amount of foliage year-round?" Tags="|agriculture|plant|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22435" PostTypeId="1" CreationDate="2021-06-21T15:42:30.727" Score="3" ViewCount="621" Body="&lt;p&gt;The summer solstice is on June 21,2021, indicating the start of summer in the northern hemisphere.&lt;/p&gt;&#xA;&lt;p&gt;Why does the Indian subcontinent experience it's warmest weather in April and May followed by the start of the rainy season in June?  I would expect the warmest weather to occur during the summer.&lt;/p&gt;&#xA;" OwnerUserId="22832" LastEditorUserId="543" LastEditDate="2021-06-22T06:24:28.957" LastActivityDate="2021-06-23T06:33:05.277" Title="Why does the Indian subcontinent experience it's warmest weather in April and May?" Tags="|climate|seasons|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22436" PostTypeId="1" AcceptedAnswerId="22438" CreationDate="2021-06-21T17:23:47.470" Score="1" ViewCount="105" Body="&lt;p&gt;In Ireland, sea cliffs tend to be on the west coast, because it's exposed to waves coming across the full width of the Atlantic, and therefore gets a lot of erosion, whereas the east coast is only exposed to waves from the much smaller Irish Sea.&lt;/p&gt;&#xA;&lt;p&gt;When looking at the geography of Japan, I expected this to be flipped around: the east coast is exposed to waves from the full width of the Pacific, whereas the west coast is only exposed to waves from the much smaller Sea of Japan.&lt;/p&gt;&#xA;&lt;p&gt;Yet to my surprise, the west coast of Japan turns out to have cliffs like Tojinbo and Matengai that look just as spectacular as anything we have in Ireland.&lt;/p&gt;&#xA;&lt;p&gt;How is this possible? What am I missing?&lt;/p&gt;&#xA;" OwnerUserId="7911" LastEditorUserId="2470" LastEditDate="2021-06-22T10:33:37.343" LastActivityDate="2021-06-22T10:33:37.343" Title="How does the west coast of Japan have cliffs?" Tags="|geography|erosion|coastal|landscape|japan|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22437" PostTypeId="2" ParentId="22435" CreationDate="2021-06-22T07:00:49.817" Score="5" Body="&lt;p&gt;While India is in the northern hemisphere, keep in mind that tropical locations don't usually follow typical seasonal patterns experienced at higher latitudes.  Instead, the tropics often have a wet season and a dry season.  The tropics do not have extreme differences in winter/summer temperatures because the amount of sunlight everyday doesn't vary too much throughout the year.  This is in contrast to high latitudes that have large fluctuations in &amp;quot;length of the day&amp;quot;, since the Earth is tilted.&lt;/p&gt;&#xA;&lt;p&gt;The summer solstice is typically considered the first day of summer, but some people do consider the summer solstice (the &amp;quot;longest day&amp;quot;) to be the middle of summer, where summer is from May-July.  Tropical locations like India consider their hottest months to be &amp;quot;summer&amp;quot; in the local vernacular, but more accurately it would be the &amp;quot;pre-monsoonal&amp;quot; season.  India would be hotter in June and July, except the monsoon season is accompanied by a shift of wind-flow direction from continental to marine.  Marine air is cooler than hot continental air because the ocean absorbs and transfers a lot of heat away.&lt;/p&gt;&#xA;&lt;p&gt;The hottest days in India are before the rainy season, because of the way the climate works there.  There are several climatic zones in India, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_of_India&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; actually has a pretty decent synopsis.  The monsoon season is caused by:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;...southeast trade winds originating from a high-pressure mass centered over the southern Indian Ocean...&#xA;These inflows ultimately result from a northward shift of the local jet stream, which itself results from rising summer temperatures over Tibet and the Indian subcontinent. The void left by the jet stream, which switches from a route just south of the Himalayas to one tracking north of Tibet, then attracts warm, humid air. The main factor behind this shift is the high summer temperature difference between Central Asia and the Indian Ocean.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;More fun facts from the same wiki page:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The nation's climate is strongly influenced by the Himalayas and the Thar Desert. The Himalayas, along with the Hindu Kush mountains in Pakistan, prevent cold Central Asian katabatic winds from blowing in, keeping the bulk of the Indian subcontinent warmer than most locations at similar latitudes. Simultaneously, the Thar Desert plays a role in attracting moisture-laden southwest summer monsoon winds that, between June and October, provide the majority of India's rainfall.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Also see the diagram below from &lt;a href=&quot;https://scied.ucar.edu/learning-zone/storms/monsoons&quot; rel=&quot;nofollow noreferrer&quot;&gt;this UCAR page&lt;/a&gt;, which discusses seasonal difference of monsoons in that region.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oZwPY.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oZwPY.png&quot; alt=&quot;Seasonal monsoon winds&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2021-06-23T06:33:05.277" LastActivityDate="2021-06-23T06:33:05.277" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22438" PostTypeId="2" ParentId="22436" CreationDate="2021-06-22T10:25:59.670" Score="4" Body="&lt;p&gt;Why are waves from full width oceans critical for the formation of &lt;a href=&quot;https://en.wikipedia.org/wiki/Cliff&quot; rel=&quot;nofollow noreferrer&quot;&gt;cliffs&lt;/a&gt;? There are many cliffs in inland regions, particularly, mountainous regions &amp;amp; escarpments along rivers.&lt;/p&gt;&#xA;&lt;p&gt;The sides of &lt;a href=&quot;https://en.wikipedia.org/wiki/Table_Mountain&quot; rel=&quot;nofollow noreferrer&quot;&gt;Table Mountain&lt;/a&gt; in South Africa appear very much like a cliff, as do the sides of &lt;a href=&quot;https://en.wikipedia.org/wiki/Mesa&quot; rel=&quot;nofollow noreferrer&quot;&gt;mesas&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Escarpment cliffs usually occur along geological faults.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Some of the largest cliffs on Earth are found &lt;strong&gt;underwater&lt;/strong&gt;. For example, an 8,000 m drop over a 4,250 m span can be found at a ridge sitting inside the Kermadec Trench.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The highest cliff in the solar system may be Verona Rupes, an approximately 20 km (12 mi) high fault scarp on Miranda, &lt;strong&gt;a moon of Uranus&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;There is no ocean on the moon &lt;a href=&quot;https://en.wikipedia.org/wiki/Miranda_(moon)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Miranda&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-06-22T10:32:02.687" LastActivityDate="2021-06-22T10:32:02.687" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22440" PostTypeId="2" ParentId="10272" CreationDate="2021-06-22T13:09:14.683" Score="5" Body="&lt;p&gt;Citing from &lt;a href=&quot;https://en.wikipedia.org/wiki/Spherical_harmonics&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;: &lt;span class=&quot;math-container&quot;&gt;$Y_l^m$&lt;/span&gt; is called a spherical harmonic function of degree &lt;span class=&quot;math-container&quot;&gt;$l$&lt;/span&gt; and order &lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt;. If we take the real part of the spherical harmonics only, there is a nice visual explanation for order and degree.&lt;/p&gt;&#xA;&lt;p&gt;The order &lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt; is the zonal wave number, that is how many waves we count walking around the sphere at constant latitude. The degree is a little more difficult to interpret, because we need to take the order into account: &lt;span class=&quot;math-container&quot;&gt;$l-|m|$&lt;/span&gt; is the number of zero crossings if we walk from pole to pole.&lt;/p&gt;&#xA;&lt;p&gt;Below you can see an example for &lt;span class=&quot;math-container&quot;&gt;$l=3$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$0\leq m \leq 3$&lt;/span&gt; (keep in mind that in order to count the number of zonal waves you also have to walk around the &amp;quot;back&amp;quot; of the sphere which you can not see in the picture):&lt;a href=&quot;https://i.stack.imgur.com/1sGCD.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1sGCD.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18833" LastActivityDate="2021-06-22T13:09:14.683" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="22441" PostTypeId="1" CreationDate="2021-06-22T13:23:04.723" Score="4" ViewCount="38" Body="&lt;p&gt;I am making a watch app, where i need to know where there is currently sun, and where its not.&lt;/p&gt;&#xA;&lt;p&gt;I need to have some sort of formula/function to insert: date, time and longitude, and get back the latitude of the civil twilight.&lt;/p&gt;&#xA;&lt;p&gt;Can someone help me?&lt;/p&gt;&#xA;" OwnerUserId="22834" LastActivityDate="2021-06-22T13:23:04.723" Title="What is the formula to input date, time and longitude. Where i can get latitude of the civil twilight back?" Tags="|sun|astronomy|python|mathematics|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22442" PostTypeId="1" CreationDate="2021-06-22T15:22:10.383" Score="4" ViewCount="322" Body="&lt;p&gt;Chem Users!&lt;/p&gt;&#xA;&lt;p&gt;Is there any guide on how to run WRF-Chem with online VPRM calculations for implementing biogenic CO2 emissions? Recently I have run successfully VPRMpreproc using the WRF-VPRMpreproc manual and useful advices from the scientists of Max Planck Institute for Biogeochemistry. Now I am trying to find out how to implement the VPRMpreproc results (e.g. EVI, LSWI, VEG_FRA, etc.) to run the WRF-Chem with online VPRM calculation. I read through WRF-GHG and WRF-Chem User Guide but found only that the WRF_VPRM_input file has to include all VPRMpreproc fields. In addition, I prepared such file and set it as an auxinput15 in the WRF-Chem namelist.input (as well as corresponding chemistry options e.g. chem_opt=16, emiss_inpt_opt=16, emiss_opt=16). The WRF-Chem log tells that the file was read successfully. However there are no any changes in CO2_BIO filed.&#xA;Thank you very much indeed&lt;/p&gt;&#xA;" OwnerUserId="18881" LastActivityDate="2021-06-22T15:22:10.383" Title="How to run WRF-VPRM" Tags="|wrf-chem|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22445" PostTypeId="1" AcceptedAnswerId="22447" CreationDate="2021-06-24T09:44:33.177" Score="2" ViewCount="376" Body="&lt;p&gt;Petroleum is not considered a rock, but it is formed by a process, so it has an age.&lt;/p&gt;&#xA;&lt;p&gt;What methods do geologists employ to determine the age of a petroleum deposit?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-06-24T10:00:32.830" LastActivityDate="2021-06-24T20:00:42.940" Title="What methods do geologists employ to detemine the age of a petroleum deposit?" Tags="|geology|stratigraphy|petroleum|dating|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22446" PostTypeId="2" ParentId="22445" CreationDate="2021-06-24T15:53:40.650" Score="1" Body="&lt;p&gt;They microscopically examine drill debris to determine if they are in the target formation , typically coral/marine shells. This is not done for all wells but for exploratory and step-out wells ( expanding a field). Primary interests are gas/oil ratio, hydrocarbon/water ratio, sulfur level. Age is only of interest as it gives information of the other properties. They have a good idea of the formations and ages before they start drilling. Exploratory and in-fill wells would be handled very differently. Drillers may refer to infill wells as&#xA;&amp;quot;post holes&amp;quot;. I have been retired for awhile but a lot of progress was/is being made in &amp;quot;measurement while drilling &amp;quot; so they know where the bits are  and where it is going in real time so microscopic exam may no longer be as important&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2021-06-24T15:53:40.650" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22447" PostTypeId="2" ParentId="22445" CreationDate="2021-06-24T20:00:42.940" Score="2" Body="&lt;p&gt;Crude oil is a product of &lt;em&gt;partial&lt;/em&gt; degradation of organic matter, e.g. of plants that lived long time ago. During photosynthesis, they constantly incorporate carbon (from &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt;) to accumulate biomass.  But carbon is not uniform, it consists of different &lt;a href=&quot;https://en.wikipedia.org/wiki/Isotope&quot; rel=&quot;nofollow noreferrer&quot;&gt;isotopes&lt;/a&gt;, and a tiny fraction of radioactive &lt;span class=&quot;math-container&quot;&gt;$\ce{^{14}C}$&lt;/span&gt;.  Slowly, over time (with a half-life of &lt;span class=&quot;math-container&quot;&gt;$\pu{5730 y}$&lt;/span&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon&quot; rel=&quot;nofollow noreferrer&quot;&gt;ref.&lt;/a&gt;), &lt;span class=&quot;math-container&quot;&gt;$\ce{^{14}C}$&lt;/span&gt; decays and yields &lt;span class=&quot;math-container&quot;&gt;$\ce{^{14}N}$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;While alive, decaying &lt;span class=&quot;math-container&quot;&gt;$\ce{^{14}C}$&lt;/span&gt; is replenished constantly, but not so for dead plants buried in the mud. So &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiocarbon_dating&quot; rel=&quot;nofollow noreferrer&quot;&gt;radiocarbon dating&lt;/a&gt;, the determination of the relative amount of still present &lt;span class=&quot;math-container&quot;&gt;$\ce{^{14}C}$&lt;/span&gt; compared to the  isotopes &lt;span class=&quot;math-container&quot;&gt;$\ce{^{12}C}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\ce{^{13}C}$&lt;/span&gt; allows to compute the time interval since the plants died.  It may be by recording remaining radiation, or by &lt;a href=&quot;https://en.wikipedia.org/wiki/Mass_spectrometry&quot; rel=&quot;nofollow noreferrer&quot;&gt;mass spectroscopy&lt;/a&gt;; the two methods complement each other.&lt;/p&gt;&#xA;&lt;p&gt;Because other elements' isotopes equally undergo nuclear reactions with other half-life times, the analysis of isotopic composition for the sake of &lt;a href=&quot;https://en.wikipedia.org/wiki/Geochronology&quot; rel=&quot;nofollow noreferrer&quot;&gt;geochronology&lt;/a&gt; need not be restrained to carbon.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;As a side note, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Isotopic_signature&quot; rel=&quot;nofollow noreferrer&quot;&gt;isotopic fingerprint&lt;/a&gt; of a sample, not necessarily (only) on the radioactive isotopes, equally allows to assign the geographic origin of (in geological time scale) contemporary samples, too.  With applications in food science, forensics, jewelry (provenance of natural &lt;em&gt;vs.&lt;/em&gt; artificial gemstones [&lt;a href=&quot;https://doi.org/10.1016/S0584-8547(01)00185-9&quot; rel=&quot;nofollow noreferrer&quot;&gt;an elder example&lt;/a&gt;]), etc.&lt;/p&gt;&#xA;" OwnerUserId="18990" LastActivityDate="2021-06-24T20:00:42.940" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22448" PostTypeId="1" CreationDate="2021-06-24T20:35:30.077" Score="1" ViewCount="86" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eeFBW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eeFBW.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I have a problem with seismic data where the minimum offset of the shot is not centered at the nearest receiver, this shift can be for 3 traces 2 or one and maybe more in the two sides !!&#xA;So is there any solution for this problem ?&lt;/p&gt;&#xA;" OwnerUserId="19164" LastEditorUserId="2470" LastEditDate="2021-06-25T05:35:02.857" LastActivityDate="2021-06-25T05:35:02.857" Title="Quality control in Seismic Acquisition - shot offset shift" Tags="|geophysics|seismology|seismic|data-analysis|data-formats|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22449" PostTypeId="1" AcceptedAnswerId="22450" CreationDate="2021-06-24T20:55:23.880" Score="4" ViewCount="622" Body="&lt;p&gt;According to Ravindra Kumar's &lt;strong&gt;Historical Geology and Stratigraphy&lt;/strong&gt;, early lifeforms of Proterozoic time could not be preserved as fossils, since they were &lt;em&gt;devoid of hard parts&lt;/em&gt;. In addition to that, it was also stated by &lt;strong&gt;Kumar&lt;/strong&gt; that,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;em&gt;with the removal of toxic contents such as sulfur, hydrogen sulfide, and carbon-di-oxide, algae and other forms of life thrived in the Proterozoic sedimentary basin.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I have tried to look for any possible answer several times but couldn't find any satisfactory ones. If anyone has an idea about that question, please try to answer.&lt;/p&gt;&#xA;&lt;p&gt;Thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="22849" LastEditorUserId="6467" LastEditDate="2021-06-24T21:04:08.043" LastActivityDate="2023-08-08T15:32:21.760" Title="Why were the early lifeforms of Proterozoic formation of India devoid of hard parts?" Tags="|paleontology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22450" PostTypeId="2" ParentId="22449" CreationDate="2021-06-24T22:16:35.710" Score="12" Body="&lt;p&gt;Simply put, life hadn't evolved any 'hard parts' yet. This applies to the Proterozoic all over the world, not just in the part of &lt;a href=&quot;https://en.wikipedia.org/wiki/Gondwana&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gondwana&lt;/a&gt; that became India.&lt;/p&gt;&#xA;&lt;p&gt;'Hard parts' usually means tissue that is already mineralized. For example, (vertebrate) &lt;a href=&quot;https://en.wikipedia.org/wiki/Bone&quot; rel=&quot;nofollow noreferrer&quot;&gt;bone&lt;/a&gt;s or (mollusk or brachiopod) &lt;a href=&quot;https://en.wikipedia.org/wiki/Exoskeleton&quot; rel=&quot;nofollow noreferrer&quot;&gt;shell&lt;/a&gt;s are made of calcite or aragonite. This material is durable over geological time, so it has time to be &lt;a href=&quot;https://en.wikipedia.org/wiki/Permineralization&quot; rel=&quot;nofollow noreferrer&quot;&gt;replaced slowly by other minerals&lt;/a&gt;. Sponge &lt;a href=&quot;https://en.wikipedia.org/wiki/Sponge_spicule&quot; rel=&quot;nofollow noreferrer&quot;&gt;spicule&lt;/a&gt;s can be made of silica, and can survive unchanged.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Cambrian&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cambrian period&lt;/a&gt; is the earliest time we find fossils of animals with hard parts anywhere. The mineralized parts vary between different types of organisms, so the best explanation we have right now is that a number of organisms independently developed mineralized parts during the Cambrian.&lt;/p&gt;&#xA;&lt;p&gt;Fossils of soft tissue can be found, but since soft tissue decomposes rapidly, these fossils are preserved by different processes. Although they can often leave some of their original atoms behind as a &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Carbonaceous_film_(paleontology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;layer of carbon&lt;/a&gt;, it's often just an &lt;a href=&quot;https://ucmp.berkeley.edu/paleo/fossilsarchive/impres.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;impression&lt;/a&gt;.  Sometimes the presence of a lifeform has to be deduced from a &lt;a href=&quot;https://en.wikipedia.org/wiki/Trace_fossil&quot; rel=&quot;nofollow noreferrer&quot;&gt;trace fossil&lt;/a&gt; such as a worm burrow.&lt;/p&gt;&#xA;&lt;p&gt;Soft tissue fossils are typically only preserved in very fine-grained sediment such as mudstone. Think about how much better a picture looks on a high-resolution screen than a lower resolution one.&lt;/p&gt;&#xA;&lt;p&gt;As &lt;a href=&quot;https://en.wikipedia.org/wiki/Lagerst%C3%A4tte&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;These formations may have resulted from carcass burial in an anoxic environment with minimal bacteria, thus delaying the decomposition of both gross and fine biological features until long after a durable impression was created in the surrounding matrix.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;For most of the Proterozoic, all we find are &lt;a href=&quot;https://en.wikipedia.org/wiki/Stromatolite&quot; rel=&quot;nofollow noreferrer&quot;&gt;stromatolites&lt;/a&gt; caused by bacterial mats capturing particles of sediment. There are hints of multicellular life from the mid-Proterozoic usually interpreted as impressions of algae.  But the most unambiguous fossils of multicellular life appear in a period at the end of the Proterozoic called the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ediacaran&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ediacaran&lt;/a&gt; (or sometimes &lt;a href=&quot;https://ucmp.berkeley.edu/vendian/vendian.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Vendian&lt;/a&gt;) starting 650 million or so years ago.  These include the famous &lt;a href=&quot;https://en.wikipedia.org/wiki/Ediacaran_biota&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ediacaran biota&lt;/a&gt; from Australia, which give the period its name. But trace fossils and what appear to be early bilaterians appear as well.&lt;/p&gt;&#xA;&lt;p&gt;Anyway, none of them contain hard parts. &lt;a href=&quot;https://pubs.geoscienceworld.org/gsa/geology/article-abstract/40/4/307/130842/The-advent-of-hard-part-structural-support-among?redirectedFrom=PDF&quot; rel=&quot;nofollow noreferrer&quot;&gt;This paper&lt;/a&gt; hints that the evolution of hard parts similar to sponge spicules may have been starting in the Ediacaran biota, but it's unclear if any of those organisms are the ancestors of anything that came later.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2023-08-08T15:32:21.760" LastActivityDate="2023-08-08T15:32:21.760" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22451" PostTypeId="1" CreationDate="2021-06-25T09:11:32.923" Score="3" ViewCount="543" Body="&lt;p&gt;Mars lost its magnetic field 4.5 billion years ago according to &lt;a href=&quot;https://depts.washington.edu/astron/old_port/TJO/newsletter/spr-2016/xinyu.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Mars lost its global magnetic field during the time of this heightened activity. After 500 million years, the Martian atmosphere is substantially destroyed, all due to the disappearance of Mars global magnetic field.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;When will the Earth lose its magnetic field and atmosphere?&lt;/p&gt;&#xA;&lt;p&gt;I am wondering: how much time do we have to find another planet to live on?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorUserId="12509" LastEditDate="2021-06-25T10:05:50.420" LastActivityDate="2021-11-29T17:39:09.290" Title="When will the Earth lose its magnetic field?" Tags="|atmosphere|geophysics|planetary-science|geomagnetism|earth-system|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22452" PostTypeId="2" ParentId="17526" CreationDate="2021-06-25T13:43:47.167" Score="2" Body="&lt;p&gt;Specifically regarding the table in your question, the last column compares the emissions not by mass but by CO&lt;sub&gt;2&lt;/sub&gt;-Eqivalent mass. That means that the number already takes into account that the global warming potential of N&lt;sub&gt;2&lt;/sub&gt;O is much higher, so every emitted molecule of N&lt;sub&gt;2&lt;/sub&gt;O counts like 298 molecules of CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&lt;p&gt;In other words, when the table says 7.9% is N&lt;sub&gt;2&lt;/sub&gt;O, it doesn't mean 7.9% of the mass or the number of molecules. The actual fraction is much less.&lt;/p&gt;&#xA;" OwnerUserId="3163" LastEditorUserId="2470" LastEditDate="2021-06-25T15:36:18.980" LastActivityDate="2021-06-25T15:36:18.980" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22453" PostTypeId="1" AcceptedAnswerId="22454" CreationDate="2021-06-25T22:21:22.430" Score="3" ViewCount="120" Body="&lt;p&gt;This is going to blow the July 2009 heat out of the water and into geostationary orbit. Dew points will also be high, between 17-20 Celsius. This goes beyond Arizona-during-the-monsoon-heat and into East Coast heat dome territory. What is the synoptic setup that is causing this combination of deadly heat and oppressive humidity, considering that the Rockies block Gulf moisture from crossing into the West and raising dew points?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Q0s01.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Q0s01.png&quot; alt=&quot;ECMWF temperature forecast for June 27, 2021 at 4:00 pm PDT&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/O7ooq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/O7ooq.png&quot; alt=&quot;ECMWF dew point forecast for June 27, 2021 at 4:00 pm PDT&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2021-06-26T00:39:38.097" Title="The Pacific Northwest is about to endure the hottest temperatures in recorded history. What is the atmospheric setup causing it?" Tags="|meteorology|weather-forecasting|extreme-weather|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22454" PostTypeId="2" ParentId="22453" CreationDate="2021-06-26T00:39:38.097" Score="4" Body="&lt;p&gt;One might say it's a &amp;quot;perfect storm&amp;quot;, heat-wave version. High pressure aloft and wind patterns driven by a low-pressure trough on the ground conspire to raise surface temperatures.&lt;/p&gt;&#xA;&lt;p&gt;According to a summary from the &lt;a href=&quot;https://www.google.com/amp/s/www.washingtonpost.com/weather/2021/06/24/pacific-northwest-heat-wave-historic/%3foutputType=amp&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Washington Post&lt;/em&gt;&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The intensity of this heat dome, based on projected atmospheric pressure at high altitudes, “is forecast to be near the strongest on record at Quillayute, WA upper-air station,” tweeted the Oregon Climate Office.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Weather Service office in Seattle wrote: “temps aloft will warm to readings as warm as we ever see — even in mid summer.”&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;A look at the tweet:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/SAr3y.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;In other words, pressures above half the normal atmospheric pressure of about 1000 mb are climbing as high aloft as they have ever been.&lt;/p&gt;&#xA;&lt;p&gt;But wait, there's more from the &lt;em&gt;Post&lt;/em&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The heat’s intensity will be augmented by what’s known as a “thermal trough,” a zone of low pressure near the ground that increases air flow from east to west or land to sea, effectively cutting off any cooling sea breezes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So there is the second element of the heat wave, not only are overland temperatures raised by the pressure pattern aloft, but cooling breezes from the sea are blocked from competing with the overland heat dome.&lt;/p&gt;&#xA;&lt;p&gt;Perhaps the editors of the &lt;em&gt;Post&lt;/em&gt; could not resist making their opinion of climate change known given this weather situation:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Evidence suggests heat domes such as this are becoming more frequent and intense due to human-caused climate change and the buildup of heat-trapping greenhouse gases in the atmosphere.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;We'd like to see the evidence before pronouncing our own opinion on such a grand cause, but the pressure distribution is certainly there.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2021-06-26T00:39:38.097" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22455" PostTypeId="1" CreationDate="2021-06-26T02:04:07.153" Score="4" ViewCount="267" Body="&lt;p&gt;From the July, 2021 &lt;em&gt;Scientific American&lt;/em&gt;:&#xA;The Carbon rocks of Oman:&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;...&lt;em&gt;fertilizing the ocean would increase the growth of phytoplankton that naturally absorb CO&lt;sub&gt;2&lt;/sub&gt; through photosynthesis'&lt;/em&gt;.  (page 47)&lt;/p&gt;&#xA;&lt;p&gt;Yes, plants on the land or on/in the water breathe in carbon dioxide and release oxygen, but....&lt;/p&gt;&#xA;&lt;p&gt;They are eaten by other organisms, including bacteria, that consume oxygen and release carbon dioxide, ultimately LOWERING levels of oxygen in the water (creating dead zones) and RAISING levels of carbon dioxide in the air....&lt;/p&gt;&#xA;&lt;p&gt;I know this because I live in the greater Chesapeake Bay area, and have relatives in the lower Mississippi area.&lt;/p&gt;&#xA;&lt;p&gt;We are always being told to REDUCE fertilizer use, not increase it, because 'blooms' of algae, cyanobacteria, etc. ultimately REDUCE levels of oxygen in the water, creating dead zones, and increase levels of CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere....&lt;/p&gt;&#xA;" OwnerUserId="20985" LastEditorUserId="2470" LastEditDate="2021-06-29T15:38:32.617" LastActivityDate="2021-06-29T15:38:32.617" Title="Wouldn't 'fertilizing' the ocean to increase cyanobacteria, algae and other phytoplankton populations actually INCREASE CO2 levels in the air?" Tags="|climate-change|oceanography|geoengineering|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22456" PostTypeId="2" ParentId="22455" CreationDate="2021-06-26T06:17:44.670" Score="5" Body="&lt;p&gt;The arrival of plants can only reduce the total CO&lt;sub&gt;2&lt;/sub&gt; levels because they metabolize carbon and oxygen. Plants don't make CO&lt;sub&gt;2&lt;/sub&gt; appear which wasn't there, they only absorb and release ambient CO&lt;sub&gt;2&lt;/sub&gt;. Two ways that the ocean can absorb more CO&lt;sub&gt;2&lt;/sub&gt; through a higher atmosphere concentration, and through acidification of limestone which can dissolve the limestone. If an algal Bloom reduces the pH of the water where corals previously were, they may dissolve some limestone and raise the CO&lt;sub&gt;2&lt;/sub&gt; levels.&lt;/p&gt;&#xA;&lt;p&gt;Seeding algae is done in the middle of the ocean using iron which encourages green plants and photosynthesis rather than cyanobacteria, in zones where there is no limestone. So it can only reduce ambient CO&lt;sub&gt;2&lt;/sub&gt; levels.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="2470" LastEditDate="2021-06-26T07:51:20.017" LastActivityDate="2021-06-26T07:51:20.017" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22457" PostTypeId="1" CreationDate="2021-06-26T12:04:59.883" Score="4" ViewCount="59" Body="&lt;p&gt;In fields that have been cultivated with rice, frequent flood irrigation can lead to soil degradation.&lt;/p&gt;&#xA;&lt;p&gt;When this type of cultivation has been implemented for several decades, will the soil suffer from irreversible (or hardly reversible) changes (permanent at the human timescale)?&lt;/p&gt;&#xA;&lt;p&gt;I would like to hear your thoughts about physical, chemical, and biological degradation (loss of structure, compaction, nutrient losses and imbalances, biodiversity loss, etc.).&lt;/p&gt;&#xA;&lt;p&gt;And more specifically, as a sub-question, will the prolonged anaerobic conditions lead to detrimental changes, impeding crop production, such as the formation of certain minerals (immobilization of nutrients) or accumulation of toxic substances (iron, hydrogen sulfide, etc.)?&lt;/p&gt;&#xA;&lt;p&gt;Will the return of aerobic conditions through different management help the soil return to acceptable conditions? Can soil degradation be alleviated completely by draining and rebuilding soil structure, letting oxygen in?&lt;/p&gt;&#xA;" OwnerUserId="22871" LastEditorUserId="6467" LastEditDate="2021-07-01T02:34:37.777" LastActivityDate="2021-07-01T02:34:37.777" Title="Do long-term anaerobic conditions caused by flood-irrigation lead to irreversible soil degradation?" Tags="|soil|agriculture|soil-science|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22458" PostTypeId="1" CreationDate="2021-06-26T16:50:53.120" Score="4" ViewCount="97" Body="&lt;p&gt;In a magnitude 5 earthquake, the ground shakes violently and it's often impossible to stay upright. This is caused by about 50-120 cm of displacement of the ground. But how much would the ground move if a magnitude 11 earthquake were to happen? This is roughly equivalent to the shaking the dinosaurs would have felt right after the asteroid hit, and I'm well aware that the Earth isn't capable of generating quakes this powerful.&lt;/p&gt;&#xA;" OwnerUserId="22877" LastEditorUserId="22877" LastEditDate="2021-06-28T17:42:52.943" LastActivityDate="2021-06-28T17:42:52.943" Title="How much would the ground be displaced in a magnitude 11 earthquake?" Tags="|geology|geophysics|earthquakes|meteorite|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22459" PostTypeId="1" CreationDate="2021-06-27T20:21:53.177" Score="1" ViewCount="39" Body="&lt;p&gt;With the absence of flying rivers, the southeast will return to its natural state condemned by the latitude it occupies: desert&lt;/p&gt;&#xA;&lt;p&gt;In the latitude of southeastern Brazil is desert all over the world, Atacama in Chile, Kalahari in Africa and Outback in Australia. For a long time INPE tried to unravel what prevented the Brazilian southeast from following its natural desert course, then with the construction of the Amazon Tall Tower Observatory (which is the highest building in all of South America) it was possible to answer: the rivers Amazon flyers.&lt;/p&gt;&#xA;&lt;p&gt;Brazil is breaking the record for deforestation in the Amazon. With the growing deforestation in the Amazon, the rainfall cycle in the southeast (and not just the southeast) is affected immediately. If the Amazon ends today there is no rain as of today.&lt;/p&gt;&#xA;&lt;p&gt;Deforestation in the Amazon certainly contributes largely to global warming, but before that it impacts our rain immediately. For those who are deniers of global warming and for those who are insensitive to deforestation in the Amazon, is it a good idea to comment on flying rivers? Will Brazil really sink without this phenomenon? I would like an answer, thanks&lt;/p&gt;&#xA;" OwnerUserId="22798" LastActivityDate="2021-06-27T20:21:53.177" Title="Rainfall index and water crisis in Brazil" Tags="|climate|amazon|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22460" PostTypeId="1" CreationDate="2021-06-28T02:17:08.783" Score="3" ViewCount="125" Body="&lt;p&gt;For instance, are we able to see the microscopic accumulation of shale or limestone?&lt;/p&gt;&#xA;&lt;p&gt;Can anyone reference me to sandstone formation observation, that would have to occur more rapidly. I’ve heard it posited that moisture evaporation in the desert could form a thin sandstone layer. Anyone an expert on this stuff?&lt;/p&gt;&#xA;" OwnerUserId="22883" LastEditorDisplayName="user20559" LastEditDate="2021-06-29T15:36:29.393" LastActivityDate="2021-06-29T15:36:29.393" Title="Are we observing sedimentary rock formation today?" Tags="|geology|rocks|sedimentology|petrology|limestone|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22461" PostTypeId="1" AcceptedAnswerId="22488" CreationDate="2021-06-28T09:08:54.473" Score="3" ViewCount="150" Body="&lt;p&gt;The Gulf Stream is the fastest ocean current in the world with peak velocities near 2m/s, a surprisingly high figure.&lt;/p&gt;&#xA;&lt;p&gt;But I think that the speed is out in the open ocean, and it would be slower near shore. How fast is it, one kilometer from shore?&lt;/p&gt;&#xA;" OwnerUserId="7911" LastEditorUserId="22648" LastEditDate="2021-06-30T18:03:38.460" LastActivityDate="2021-07-03T07:02:11.537" Title="How fast is the Gulf Stream near shore?" Tags="|oceanography|ocean-currents|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22462" PostTypeId="1" CreationDate="2021-06-28T12:36:10.647" Score="2" ViewCount="2487" Body="&lt;p&gt;A certain land (urban area, forest etc.) is under water for a certain period. How can we distinguish that the area is flooded or waterlogged? What are the criteria?&lt;/p&gt;&#xA;" OwnerUserId="22648" LastEditorUserId="22648" LastEditDate="2021-10-05T06:26:54.620" LastActivityDate="2021-10-05T07:42:58.873" Title="What is the difference between waterlogging and flooding?" Tags="|flooding|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22463" PostTypeId="2" ParentId="22462" CreationDate="2021-06-28T15:14:41.237" Score="4" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Waterlogging_(agriculture)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Waterlogging&lt;/a&gt; is a situation were soil is either fully or near saturated most of the time, the air phase is restricted and aerobic conditions prevail. Waterlogged soil may appear dry on the surface. The soil does not need to be submerged to be waterlogged.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Flood&quot; rel=&quot;nofollow noreferrer&quot;&gt;Flooding&lt;/a&gt; is a temporary submersion of land by water. The duration of a flood may be very short, such as hours, or it may prolonged, such a weeks or months in flatter regions with poor drainage. Eventually flood waters recede and the soil may eventually dry out.&lt;/p&gt;&#xA;&lt;p&gt;A &lt;a href=&quot;https://en.wikipedia.org/wiki/Flash_flood&quot; rel=&quot;nofollow noreferrer&quot;&gt;flash flood&lt;/a&gt; is a very rapid flooding of low lying areas or dry waterways usually associated with sudden heavy rainfall or melt water from ice or snow.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-06-28T15:14:41.237" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22464" PostTypeId="2" ParentId="22460" CreationDate="2021-06-28T23:57:22.983" Score="7" Body="&lt;p&gt;The transformation of sand into sandstone per se cannot be directly witnessed, as it's happening deep in the earth. However, there are types of &lt;a href=&quot;https://en.wikipedia.org/wiki/Cementation_(geology)&quot; rel=&quot;noreferrer&quot;&gt;cementation&lt;/a&gt; that happen quickly and in plain view:&lt;/p&gt;&#xA;&lt;p&gt;A &lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/cementation&quot; rel=&quot;noreferrer&quot;&gt;ScienceDirect article on Cementation&lt;/a&gt; says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Cementation is the precipitation of a binding material around grains, thereby filling the pores of a sediment. Berner (1971, p. 97) states that “cementation by silica must be predominantly a phenomenon of later &lt;a href=&quot;https://en.wikipedia.org/wiki/Diagenesis&quot; rel=&quot;noreferrer&quot;&gt;diagenesis&lt;/a&gt; because almost no examples are found in recent marine sediments.” In contrast, cementation by &lt;a href=&quot;https://en.wikipedia.org/wiki/Calcium_carbonate&quot; rel=&quot;noreferrer&quot;&gt;calcium carbonate&lt;/a&gt; occur rapidly after deposition. A good example is &lt;a href=&quot;https://en.wikipedia.org/wiki/Beachrock&quot; rel=&quot;noreferrer&quot;&gt;beachrock&lt;/a&gt;, a mix of beach and intertidal sand (usually carbonate and skeletal fragments) cemented by CaCO3 in subtropical to tropical climates. The cement forms so rapidly that human artifacts only a few decades old are commonly found cemented into the beachrock.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;-- David R. Montgomery, ... Henri Spaltenstein,  &lt;em&gt;International Geophysics&lt;/em&gt;, 2000 quoted at sciencedirect.com&lt;/p&gt;&#xA;&lt;p&gt;I have witnessed an early stage of this personally. When I was a kid, my brother and I used to risk typhoid by visiting a stream a couple of blocks from our house. I'd walk out on a sandbar left behind by a recent flood and pick up a fist-sized quartz rock that looked collectible.&lt;/p&gt;&#xA;&lt;p&gt;But the underside of the rock sometimes had smaller pebbles and sand grains cemented to the underside. They couldn't be brushed off-some mineral had connected the grains to the larger rock. There were clumps of cemented sand grains and pebbles in the sandbar.&lt;/p&gt;&#xA;&lt;p&gt;This mineral might have been clay minerals derived from the feldspar that used to hold the quartz together, but in this urban environment, calcite leached from concrete and iron oxide were also possible.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2021-06-29T00:03:39.277" LastActivityDate="2021-06-29T00:03:39.277" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22465" PostTypeId="1" CreationDate="2021-06-28T23:11:21.570" Score="1" ViewCount="96" Body="&lt;p&gt;What is the brief description of Disease Stress Water Index (&lt;a href=&quot;https://www.indexdatabase.de/db/i-single.php?id=106&quot; rel=&quot;nofollow noreferrer&quot;&gt;DSWI&lt;/a&gt;)? According to the link, it has been defined as to detect water-stressed crops at a canopy level. I am looking for a bit more information on this index.&lt;/p&gt;&#xA;" OwnerUserId="22887" OwnerDisplayName="Arthur_Morgan" LastEditorUserId="22648" LastEditDate="2021-06-29T15:36:19.790" LastActivityDate="2021-06-29T15:36:19.790" Title="DSWI brief description" Tags="|water|agriculture|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22468" PostTypeId="1" AcceptedAnswerId="22550" CreationDate="2021-06-30T12:06:45.460" Score="7" ViewCount="1144" Body="&lt;p&gt;I am doing an study on Sentinel-5p TROPOMI images. I would like to convert the data from mole/m&lt;sup&gt;2&lt;/sup&gt; to μg/m&lt;sup&gt;3&lt;/sup&gt;, for this I know I need the height data of the measurements. I have looked for them and I have only found for tropospheric ozone (6 km), would you know for CO, SO&lt;sub&gt;2&lt;/sub&gt; and NO&lt;sub&gt;2&lt;/sub&gt; the height of the vertical column?&lt;/p&gt;&#xA;&lt;p&gt;Thank you very much,&#xA;Irene B.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;The Sentinel product gives you different layers, as you can see in the image, the NO2 gives a layer of tropospheric data and another of stratospheric data... by making this separation, shouldn't they be assuming a limit to the height of the column in which the data is separated by layers?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/nJpOJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nJpOJ.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;I understand that the height of the limit of these can vary, but I would like to arrive at an approximate average value.&lt;/p&gt;&#xA;" OwnerUserId="22895" LastEditorUserId="543" LastEditDate="2021-07-17T06:26:26.167" LastActivityDate="2021-07-18T04:41:28.033" Title="How do I convert Sentinel-5p / TROPOMI vertical column density to concentration?" Tags="|atmosphere|remote-sensing|air-quality|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22469" PostTypeId="2" ParentId="22468" CreationDate="2021-06-30T13:47:47.177" Score="7" Body="&lt;p&gt;The unit mole / m² has dimensions count per area; the unit µg / m³ has dimensions mass per volume.  To go from a quantity per area to a quantity per volume, you need to understand some properties of the instrument.&lt;/p&gt;&#xA;&lt;p&gt;The spectrometer on Sentinel-5P is TROPOMI.  TROPOMI is an imaging spectrometer, meaning it measures the spectrum of top-of-atmosphere electromagnetic radiation at various wavelengths.  Such a spectrum (the &amp;quot;level 1 data&amp;quot;) may look like this:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Ez6l1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ez6l1.png&quot; alt=&quot;simulated TROPOMI spectrum&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;em&gt;Source: Hu et al. (2016), DOI:10.5194/amt-2016-108, CC-BY 3.0&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Original caption:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Simulated TROPOMI spectra in the NIR and SWIR channels for a scenario from the global ensemble,&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;For most users, these spectra do not readily show what they are actually interested in.  However, from these spectra it is possible to calculate the atmospheric composition of various trace gases, because each gas has its own unique spectral signature.  How this works is too complicated to explain in a Stack Exchange answer, but is covered in text books and university courses.&lt;/p&gt;&#xA;&lt;p&gt;For a down-looking instrument like TROPOMI, it is difficult to resolve vertical information.  For some species (some trace gases) we may have a rough idea whether the quantities calculated are close to the surface or close to the top of the atmosphere, for others we really only have a clue about the total column amount (meaning the total amount between the surface and the satellite).  Therefore, when a data product reports a column integrated amount, it is not possible to assign this to a specific height.&lt;/p&gt;&#xA;&lt;p&gt;However, a retrieval may be more sensitive for some heights than for others.  Maybe it mostly sees the top part of the column, maybe mostly the bottom part.  One way to express this is by the averaging kernel.  The averaging kernel tells you to what height the total column measurement is most sensitive:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lkGbJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lkGbJ.png&quot; alt=&quot;example averaging kernel&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;em&gt;Source: Borsdorff et. al (2018), DOI:10.5194/amt-11-5507-2018, CC-BY 4.0&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Original caption:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;TROPOMI CO total column averaging kernels for 10 November 2017. The global average is shown for three different categories of cloudiness strict cloud clearing (black), clear-sky equivalent (yellow), and high optical thick clouds (blue). The standard deviation is indicated as error bars.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;What does this mean?  Firstly, the averaging kernel is situation dependent.  Maybe that's why you've been told you need the height of the inversion layer, but more likely people may use the height of the inversion layer to &lt;em&gt;model&lt;/em&gt; where certain species are likely to be located, using a model that simulates atmospheric chemistry and dynamics.  The figure shown here shows global averages for those averaging kernels for a single day (at least that what it claims; more likely it shows the average of all measurements, which is not strictly the same, as the instrument samples some places more than others).  Secondly, it's very broad.  The black line shows the case for clear-sky.  The averaging kernel is rather flat, meaning that CO at various heights contributes pretty much equally to the total column amount.  The blue line shows  more sensitivity to upper parts of the atmosphere, but that's because the lower part is obscured by clouds.&lt;/p&gt;&#xA;&lt;p&gt;In this case, there is no vertical height to convert from mole/m² to µg/m³.  I suppose you could estimate the mass of a column of atmosphere, but it's more conventional to report in mole/m², such as your source does.  Or you could use an atmospheric chemistry model that estimates what a likely vertical distribution looks like, based on various characteristics.  I'm not an atmospheric chemist so I can't say a lot about how well that works.&lt;/p&gt;&#xA;&lt;p&gt;Some averaging kernels look more narrow (NB: not TROPOMI).  I think this one is about simulated aerosol retrievals with different channels:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zfvRA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zfvRA.png&quot; alt=&quot;other averaging kernels&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;em&gt;Source: Colosimo et. al (2015), DOI:10.5194/amtd-8-11853-2015, CC-BY 3.0&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Original caption:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Example of averaging kernel vs. altitude. The simulation refers to a convolved spectrum of spectral resolution ∆ν = 0.01 cm −1 and FWHM = 0.05 cm −1 with a solar zenith angle SZA = 45 • and an instrument viewing angle of 30 • off-nadir. The AK are color coded for different altitude ranges. On the right, a zoom between 0 and 12 km is shown.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In this case, some vertically resolved information is available.&lt;/p&gt;&#xA;&lt;p&gt;To truly get vertically resolved information, you want to use a limb sounder.  Instead of looking down, a limb sounder looks at the horizon, scanning up and down.  Each measurement only sees a narrow vertical section of the atmosphere.  However, it has a poor horizontal resolution and worse temporal sampling.  In the special case of solar occultation, the signal to noise ratio gets very high, but any given location only has measurements about twice a year.  Comparing the three is possible.  From personal experience, I can tell you that this is a challenge for any scientist :)&lt;/p&gt;&#xA;&lt;h2 id=&quot;followup-question&quot;&gt;Followup question&lt;/h2&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Sentinel product gives you different layers, as you can see in the image, the NO2 gives a layer of tropospheric data and another of stratospheric data... by making this separation, shouldn't they be assuming a limit to the height of the column in which the data is separated by layers?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Yes, they should.  They have different channels that are sensitive to different heights, but this sensitivity is still rather broad.  For example, maybe they have a channel that's sensitive to 0-8 km, 2-10 km, 4-14 km, 6-16 km, 8-20 km, 10-30 km, then use a numerical method to estimate the partial column for 0-12 km and 12-30 km.  If I see such a claim, I would look closely at the papers describing the retrieval method to see how exactly they calculated what they call tropospheric and stratospheric data.  I haven't read those papers in case of TROPOMI, but as a downlooking spectrometer, it's not going to be a sharp cutoff.  Maybe the user guide has some information that can help with the vertical attribution?&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2021-07-14T13:31:35.073" LastActivityDate="2021-07-14T13:31:35.073" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="22471" PostTypeId="2" ParentId="19496" CreationDate="2021-06-30T15:52:37.460" Score="1" Body="&lt;p&gt;The simplest method is the spectral ratio method where the frequency spectra at two different depth levels in the VSP are computed and divided i.e. the ratio of the spectra. IN theory the slope of this spectral ratio is related to the attenaution factor Q. However, this method is not very robust and the data needs careful preconditioning to remove reflections, multiples, conversions etc. There are many others methods that have been developed and are described in the literature e.g. Geophysics.&lt;/p&gt;&#xA;" OwnerUserId="3104" LastActivityDate="2021-06-30T15:52:37.460" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22472" PostTypeId="2" ParentId="19408" CreationDate="2021-06-30T15:58:42.490" Score="0" Body="&lt;p&gt;The keyword that you are looking for is a spectrogram, this is the plot of a frequency time analysis. If you search for that term for can find many examples of what you are after e.g. &lt;a href=&quot;https://fairyonice.github.io/implement-the-spectrogram-from-scratch-in-python.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://fairyonice.github.io/implement-the-spectrogram-from-scratch-in-python.html&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;On a related note if you are interested in ambient noise tomography you might want to look at the MSnoise package &lt;a href=&quot;https://github.com/ROBelgium/MSNoise&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://github.com/ROBelgium/MSNoise&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3104" LastActivityDate="2021-06-30T15:58:42.490" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22473" PostTypeId="2" ParentId="21283" CreationDate="2021-06-30T18:13:42.980" Score="2" Body="&lt;p&gt;Definitely an echinoid (sea urchin) and they are often found in the flints in the chalk cliffs along the south coast of the UK. Seaford in Sussex is particularly well known for these types of fossils.&lt;/p&gt;&#xA;" OwnerUserId="3104" LastActivityDate="2021-06-30T18:13:42.980" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22475" PostTypeId="1" CreationDate="2021-07-01T10:28:46.410" Score="1" ViewCount="106" Body="&lt;p&gt;Good morning,&lt;/p&gt;&#xA;&lt;p&gt;I am working with &lt;strong&gt;Sentinel-5p products&lt;/strong&gt;, my final thesis is to establish a methodology for processing this type of images, from downloading to the implementation of a colour map with the different distributions according to concentrations.&#xA;Any help on this subject is of great help to me.&lt;/p&gt;&#xA;&lt;p&gt;I download the products from ''Sentinel-5p Pre-operations Data Hub'', but the L2, ozone and sulphur dioxide products do not open in SNAP(Sentinel Application Platform)  CO, NO and the aerosol index do open.&#xA;I have read other forums and they tell me that they are not compatible and that I should download toolboxes, but I don't know how to do it.&lt;/p&gt;&#xA;&lt;p&gt;I would be very grateful to anyone who has worked with me and would like to help me.&lt;/p&gt;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="22895" LastEditorUserId="2470" LastEditDate="2021-07-01T12:17:18.127" LastActivityDate="2021-07-01T12:17:18.127" Title="Why does SNAP let me open some Sentinel-5p products and not others?" Tags="|atmosphere|remote-sensing|air-quality|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="22476" PostTypeId="1" AcceptedAnswerId="22486" CreationDate="2021-07-01T21:57:55.523" Score="8" ViewCount="1185" Body="&lt;p&gt;So if dry air is just low humidity, meaning it has the capacity to hold more water vapour, it should make sense that the &lt;strong&gt;water&lt;/strong&gt; &lt;strong&gt;droplets&lt;/strong&gt; from the clouds will just evaporate and fill that dry air with the evaporated &lt;strong&gt;water vapour&lt;/strong&gt;. &lt;em&gt;Right&lt;/em&gt;?&lt;/p&gt;&#xA;&lt;p&gt;However, why does the dry air cause the &lt;strong&gt;water droplets&lt;/strong&gt; to evaporate in the first place, what provides the water molecules with enough energy to become a gas (water vapour)? Is there an intuitive way to understand this concept without any fancy equations?&lt;/p&gt;&#xA;&lt;p&gt;From what I have read this process is called &lt;a href=&quot;https://www.weather.gov/source/zhu/ZHU_Training_Page/clouds/clouds_dissipation/cloud_dissipation.htm#:%7E:text=the%20cloud%20mixing%20with%20drier%20air&quot; rel=&quot;noreferrer&quot;&gt;entrainment&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;In advance, thank you for your answers, I have been trying understand cloud formation and this part really got to me, can't wrap my head around the reason why clouds would dissipate (or &lt;em&gt;partially&lt;/em&gt; dissipate) when mixing with dryer air.&lt;/p&gt;&#xA;" OwnerUserId="22902" LastActivityDate="2024-03-21T01:03:11.593" Title="Why do clouds dissipate when mixing with dry air?" Tags="|meteorology|clouds|" AnswerCount="5" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="22477" PostTypeId="2" ParentId="22476" CreationDate="2021-07-02T06:42:10.000" Score="8" Body="&lt;p&gt;You may be assuming cloud droplets are in a &amp;quot;rest&amp;quot; state or some finite ordered state. Cloud droplets are actually growing/shrinking continuously as each molecule of water reacts to its environment and either condenses, evaporates, or remains in solution. Atmospheric pressure aloft is also low enough that the &amp;quot;boiling point&amp;quot; of water decreases, so it can &lt;a href=&quot;https://s3-us-west-2.amazonaws.com/courses-images-archive-read-only/wp-content/uploads/sites/53/2014/08/19212109/20140811155434493809.png&quot; rel=&quot;noreferrer&quot;&gt;exist as water vapor at lower temperatures&lt;/a&gt; than you might think.&lt;/p&gt;&#xA;&lt;p&gt;There is plenty of &amp;quot;energy&amp;quot; in the atmosphere to allow microdroplets to evaporate: mechanical, heat, and radiant energy. In general you should think of suspended water droplets more like &lt;a href=&quot;https://www.uae-nature.com/wp-content/uploads/2019/10/numerical_approach1-DNS_animation.gif&quot; rel=&quot;noreferrer&quot;&gt;a chaotic system&lt;/a&gt; and less like a &lt;a href=&quot;https://image4.slideserve.com/7319146/lecture-11-growth-of-cloud-droplet-in-warm-clouds-n.jpg&quot; rel=&quot;noreferrer&quot;&gt;collection of droplets&lt;/a&gt;. Cloud droplets are never isolated or steady-state.  Change in a cloud is being driven by the gradient of saturation, temperature, pressure, and the constant movement of the air. The droplets are also constantly impacting each other, which causes them to grow or break apart.  As drier air becomes part of that environment, the water molecules at the edges of the droplets have less of a chance of remaining in solution.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2021-07-02T06:42:10.000" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22478" PostTypeId="1" AcceptedAnswerId="22479" CreationDate="2021-07-02T10:48:16.390" Score="9" ViewCount="5480" Body="&lt;p&gt;Currently it is winter in Antarctica. According to news I read, Antarctica has set a new record high temperature, above 18 °C. How did this temperature records occur?&lt;/p&gt;&#xA;" OwnerUserId="2819" LastEditorUserId="2470" LastEditDate="2021-07-06T06:55:39.870" LastActivityDate="2021-07-06T06:55:39.870" Title="I just read news that Antarctica had set a new record high temperature, above 18 °C. How can this be the case if it is currently winter there?" Tags="|climate-change|climate|temperature|antarctica|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22479" PostTypeId="2" ParentId="22478" CreationDate="2021-07-02T12:08:40.200" Score="39" Body="&lt;p&gt;You just read the news too fast. WMO &lt;a href=&quot;https://public.wmo.int/en/media/press-release/wmo-verifies-one-temperature-record-antarctic-continent-and-rejects-another&quot; rel=&quot;noreferrer&quot;&gt;announced&lt;/a&gt; that, after evaluation by a committee, they have validated the 18.3°C temperature recorded &lt;em&gt;in February&lt;/em&gt; (i.e., in summer) last year:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;GENEVA, 1 July 2021 (WMO) - The World Meteorological Organization&#xA;(WMO) has recognized a new record high temperature for the Antarctic&#xA;continent of 18.3° Celsius on 6 February 2020 at the Esperanza station&#xA;(Argentina).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2021-07-02T12:08:40.200" CommentCount="16" ContentLicense="CC BY-SA 4.0" />
  <row Id="22480" PostTypeId="2" ParentId="22476" CreationDate="2021-07-02T12:18:02.590" Score="4" Body="&lt;p&gt;Clouds form in areas where the relative humidity exceeds 100%. Add enough dry air to a cloud and the relative humidity drops below 100%, making the cloud dissipate. It's that simple.&lt;/p&gt;&#xA;&lt;p&gt;Or almost that simple. Entrainment occurs because clouds are large. The dry air isn't instantaneously injected throughout the cloud. It instead erodes the cloud from the edges. The process of evaporation decreases the temperature thereby increasing the density. This in turn makes the cooled air mass sink, which allows more dry air to enter the cloud. The relative humidity decreases even more as the sinking cooled air warms.&lt;/p&gt;&#xA;&lt;p&gt;Or perhaps not that simple at all. Dry air can at times create clouds, very nasty clouds, called supercells. In the North American Great Plains, a large mass of very dry air can be flowing eastward from the Rocky Mountains and meet with a large mass of very moist air flowing to the northwest from the Gulf of Mexico. Because dry air is more dense than than moist air, the dry air at the boundary between the two air masses can slip underneath the moist air mass. This buoys the moist air upward, thereby creating clouds. This phenomenon of a dew point difference between the dry and moist air is known as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Dry_line&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dry Line&lt;/a&gt;.  If conditions are just right (or just wrong), those clouds can become very large and very tall. A &lt;a href=&quot;https://en.wikipedia.org/wiki/Supercell&quot; rel=&quot;nofollow noreferrer&quot;&gt;Supercell&lt;/a&gt; can result in large hail, and at times, tornadoes.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorDisplayName="user1066" LastEditDate="2021-07-04T07:37:05.763" LastActivityDate="2021-07-04T07:37:05.763" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22481" PostTypeId="1" CreationDate="2021-07-02T13:27:44.773" Score="5" ViewCount="369" Body="&lt;p&gt;A year or so ago, I finally implemented a little mechanism which, every five minutes, fetches weather data from SMHI (Swedish official organization, having kept track of temperatures and stuff since the mid-1700s) for a GPS coordinate quite close to my house. (Less than 1 km, for privacy.)&lt;/p&gt;&#xA;&lt;p&gt;Since I really love it when it rains, it then extracts all predictions of rain and puts them into my calendar which I constantly see on my screen, so that I can at a glance see exactly when rain is predicted for the current days and 13 more days into the future. (Obviously, each time, it deletes the old data first.)&lt;/p&gt;&#xA;&lt;p&gt;But this is where it gets weird. It might say right now that it's going to rain sometime tomorrow, but yesterday, or hours before, it was five days until the next rain. And the very same day, it might say that it's going to rain in 10 minutes, but then it increases to 20 minutes, then an hour left, then 3 hours left, then no rain at all for 3 days. Then no rain for 7 days. Then rain tomorrow. It seems to vary so wildly as to be completely unreliable and useless.&lt;/p&gt;&#xA;&lt;p&gt;It feels like I might as well just remove this mechanism as I could just as well just make my own random guesses and probably be as accurate.&lt;/p&gt;&#xA;&lt;p&gt;But why is this? I thought that weather predictions were extremely reliable at this point, with global, advanced models processing enormous amounts of information with powerful computers around the clock and whatnot. Yet they seem to have no clue? Is predicting rain especially difficult, perhaps? Are just SMHI specifically very incompetent?&lt;/p&gt;&#xA;" OwnerUserId="22904" LastEditorUserId="2470" LastEditDate="2021-07-02T14:27:11.490" LastActivityDate="2021-07-12T19:18:33.207" Title="Why are rain weather predictions (apparently) so unreliable still in the year 2021?" Tags="|weather-forecasting|rainfall|rain|predictability|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22482" PostTypeId="2" ParentId="22476" CreationDate="2021-07-02T13:55:24.973" Score="2" Body="&lt;p&gt;(English is not my first language, so be nice if the words are wrong)&lt;/p&gt;&#xA;&lt;p&gt;Basically it's kinetic energy of the water molecules (above 0 K, absolute zero); that energy isn't evenly distributed, so a few molecules have higher energy than others.&lt;/p&gt;&#xA;&lt;p&gt;Some have enough energy to &amp;quot;jump off&amp;quot;, becoming an isolated &amp;quot;gas molecule&amp;quot;, leaving the others behind with somewhat less kinetic energy (preservation of energy).&lt;/p&gt;&#xA;&lt;p&gt;So that's how sweating works: You dry and cool down at the same time.&lt;/p&gt;&#xA;&lt;p&gt;The mechanism also allows you to boil water; if it weren't like that then your water would be all 99.9°C hot, then suddenly all gone as vapor when it reached 100°C.&lt;/p&gt;&#xA;&lt;p&gt;When vapor rises to higher atmosphere, the air is colder (typically) and the air can hold less water, so it's condensing (fog, clouds).&#xA;If the process continues, drops of water may fall down.&#xA;That does not mean they actually hit the ground as they may evaporate again.&lt;/p&gt;&#xA;" OwnerUserId="22905" LastEditorUserId="2470" LastEditDate="2021-07-05T09:59:55.337" LastActivityDate="2021-07-05T09:59:55.337" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22483" PostTypeId="2" ParentId="22481" CreationDate="2021-07-02T15:48:16.767" Score="5" Body="&lt;p&gt;You are expecting too much. Weather forecasting has become quite reliable.&lt;/p&gt;&#xA;&lt;p&gt;There are exceptions. One exception is predicting what will happen more than seven days into the future. At ten days into the future, forecasts remain pretty much a random guess. The 1960s discovery that weather is chaotic (&lt;a href=&quot;https://earthscience.stackexchange.com/a/628/239&quot;&gt;Predictability: Does the flap of a butterfly's wings in Brazil set off a tornado in Texas?&lt;/a&gt;) remains a challenge, and acts as a limit to long-term weather forecast accuracy.&lt;/p&gt;&#xA;&lt;p&gt;Another exception is predicting what will happen in the next few hours. The various high precision weather models used by weather agencies are only run a few times a day. In between, lower precision heuristic algorithms are used to fill in the blanks. Those high precision models run on some of the world's largest supercomputers, and it can take hours to complete a run. For example, the European Centre for Medium-Range Weather Forecasts runs its high resolution Integrated Forecast System twice a day. The ECMWF is not going to make a special-purpose run because you want a forecast for the next ten minutes.&lt;/p&gt;&#xA;&lt;p&gt;Predicting when and where a little popup thundershower will occur remains highly challenging. For example, the ECMWF has a 9 km horizontal resolution. A popup thundershower might affect less than a square kilometer. Predicting when and where a squall line or a front will hit is a bit easier, and is much more important. The heuristics used for short term forecasts focus on the important things -- things that can cause damage. The little popup thundershowers that make your day or spoil someone's picnic does not qualify as such.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2021-07-02T15:48:16.767" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22485" PostTypeId="1" CreationDate="2021-07-03T04:17:12.653" Score="1" ViewCount="111" Body="&lt;p&gt;I am studying some maps of prehistoric cultures in North America, noting the relationship between their villages and the rivers they are near. I notice each civilization seems grouped around rivers that are constrained to a certain area. E.g. culture X has villages all along river A, river B, and river C. Culture Y, just over some mountain range, has villages all along river D and E, but no villages near the river used by culture X. Similarly, Culture Z isn't too far away, yet it has its own rivers entirely, having villages at the headwaters and all along its length.&lt;/p&gt;&#xA;&lt;p&gt;I'm trying to find if there is some geological connection between the rivers, e.g. A, B, and C are part of the same &amp;quot;watershed&amp;quot; or maybe same &amp;quot;river valley&amp;quot;, &amp;quot;river system&amp;quot; or something, but these terms don't seem to fit my searches. The term &amp;quot;river valley&amp;quot; seems closest, but I can't find people using this term in the same context, and also the rivers are 100-200 miles long, hardly seems a valley can be that big. These are rivers flowing into &amp;quot;dips&amp;quot; that are easily 100 miles wide.&lt;/p&gt;&#xA;&lt;p&gt;Is there any common term and way a geologist will find a connection between several rivers sharing a specific area?&lt;/p&gt;&#xA;" OwnerUserId="17645" LastActivityDate="2021-07-03T16:42:17.167" Title="What term to geologists use to refer to several rivers constrained to a particular area?" Tags="|rivers|terminology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22486" PostTypeId="2" ParentId="22476" CreationDate="2021-07-03T05:41:51.670" Score="2" Body="&lt;p&gt;Clouds are large masses of tiny liquid water droplets suspended in water vapor-saturated atmosphere (100% relative humidity). At a constant altitude and temperature, this system is in equilibrium: there's always some exchange of water molecules from the surface of these droplets into the surrounding saturated atmosphere and vice versa. Water droplets will not grow in size and neither will the size of the cloud; kinetic energy that exists at any gas/liquid interface controls this system and is fed by the sun (thermal energy) and wind (motion energy).&lt;/p&gt;&#xA;&lt;p&gt;Once the liquid water droplets find themselves in an atmosphere that is now, say, 20% relative humidity, the water molecules that spall off the surfaces of the droplets are no longer replaced by nearby water molecules and the droplets become smaller until they disappear entirely. This happens from the cloud edges and progresses inward until the cloud disappears.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2021-07-03T05:41:51.670" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22487" PostTypeId="2" ParentId="22485" CreationDate="2021-07-03T06:26:02.193" Score="1" Body="&lt;p&gt;Think about this backwards: instead of thinking that civilizations happen to live in specific watersheds, consider that it is the mountains that force them to live in these separate watersheds. Rivers, like many early cultures, are &amp;quot;orographically constrained&amp;quot;, topography will dictate how separate and distinct they become over time from one another.&lt;/p&gt;&#xA;&lt;p&gt;Sure, other factors come into play, like distance, weather, and food availability, but mountains, aka &amp;quot;orographic barriers&amp;quot; require significant material and energy resources to overcome. Even low hills present a challenge to a calorie-scarce community. An &amp;quot;orographic barrier&amp;quot; is an &amp;quot;energy barrier&amp;quot; in many different ways.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2021-07-03T06:26:02.193" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22488" PostTypeId="2" ParentId="22461" CreationDate="2021-07-03T07:02:11.537" Score="4" Body="&lt;p&gt;Along the eastern US coast, the Gulf Stream travels over broad, and shallow, continental shelf. On the western edge of this shelf, friction slows the Gulf Stream as does seasonally driven local convection and surface gyres. In many places along the east coast, local currents may be reversed well beyond 1km from shore, depending on the season. Check out this &lt;a href=&quot;https://svs.gsfc.nasa.gov/vis/a000000/a003800/a003827/perpetual_ocean_1080p30.mp4&quot; rel=&quot;nofollow noreferrer&quot;&gt;Perpetual Ocean visualization&lt;/a&gt; from Godard Space Center.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/n7YTi.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/n7YTi.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2021-07-03T07:02:11.537" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22489" PostTypeId="2" ParentId="22485" CreationDate="2021-07-03T16:42:17.167" Score="2" Body="&lt;h2&gt;Drainage basin or drainage system&lt;/h2&gt;&#xA;&lt;p&gt;Drainage basin are defined by drainage pattern, which is controlled by the underlying geology and landform.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WRiLF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WRiLF.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;more on what creates the pattern.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.wvca.us/envirothon/pdf/Drainage%20Patterns.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.wvca.us/envirothon/pdf/Drainage%20Patterns.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2021-07-03T16:42:17.167" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22490" PostTypeId="1" AcceptedAnswerId="22500" CreationDate="2021-07-03T19:38:05.933" Score="7" ViewCount="250" Body="&lt;p&gt;I am trying to understand the concrete process of how a meteorologist at a weather forecast office produces the different types of weather forecasts.&#xA;I understand how numerical weather models work, but I would like to learn how the model output is turned into a forecast and to what extend it is improved by a skilled meteorologist.&lt;/p&gt;&#xA;&lt;p&gt;I have found an older reference from 1993 that has some information on the workflow,&#xA;&lt;a href=&quot;https://esrl.noaa.gov/gsd/eds/gfesuite/pubs/AWIPS-Forecast-Preparation-System.pdf&quot; rel=&quot;noreferrer&quot;&gt;https://esrl.noaa.gov/gsd/eds/gfesuite/pubs/AWIPS-Forecast-Preparation-System.pdf&lt;/a&gt;&#xA;but this is probably outdated and doesn't talk about the meteorological side.&lt;/p&gt;&#xA;&lt;p&gt;There are a lot of different forecast products from text to graphical products, so my question might be an overly broad one, but I haven't found much information so far, so I don't want to be too restrictive.&lt;/p&gt;&#xA;&lt;p&gt;What concrete model outputs do forecasters look at and to what extend do they use local observations and experience?&lt;/p&gt;&#xA;" OwnerUserId="22910" LastEditorUserId="22910" LastEditDate="2021-07-03T20:42:02.233" LastActivityDate="2021-07-05T23:26:29.700" Title="How is a weather forecast really done?" Tags="|meteorology|weather-forecasting|united-states|" AnswerCount="2" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="22491" PostTypeId="2" ParentId="22478" CreationDate="2021-07-04T01:22:13.217" Score="6" Body="&lt;p&gt;Supplemental to &lt;a href=&quot;https://earthscience.stackexchange.com/a/22479/6031&quot;&gt;Jean-Marie Prival's answer&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;The February 2020 event was already discussed here in a question posted the same day this went public: &lt;a href=&quot;https://earthscience.stackexchange.com/q/19145/6031&quot;&gt;What is the second thermometer in the image from the Esperanza Antarctic temperature record?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://twitter.com/SMN_Argentina/status/1225455484259442691&quot; rel=&quot;nofollow noreferrer&quot;&gt;twitter.com&lt;/a&gt;&#xA;&lt;a href=&quot;https://public.wmo.int/en/media/news/new-record-antarctic-continent-reported&quot; rel=&quot;nofollow noreferrer&quot;&gt;wmo.int&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.bloomberg.com/news/articles/2020-02-07/it-s-t-shirt-weather-in-antarctica-as-temperature-breaks-record&quot; rel=&quot;nofollow noreferrer&quot;&gt;bloomberg.com&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.nytimes.com/aponline/2020/02/07/world/europe/ap-eu-switzerland-un-antarctica.html?searchResultPosition=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;nytimes.com&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.theguardian.com/world/2020/feb/07/antarctica-logs-hottest-temperature-on-record-with-a-reading-of-183c&quot; rel=&quot;nofollow noreferrer&quot;&gt;theguardian.com&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The tweet contained an image of a literal analogue thermometer which did show the 18.3°C... but curiously enough, also &lt;em&gt;another&lt;/em&gt; thermometer showing merely 10.0°C.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7XnXh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7XnXh.jpg&quot; alt=&quot;The image tweeted by SMN Argentina&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The answer to that question is that this pair forms a wet-dry bulb system for measuring humidity.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="-1" LastEditDate="2021-07-04T23:34:32.190" LastActivityDate="2021-07-04T23:34:32.190" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22492" PostTypeId="1" CreationDate="2021-07-04T01:31:05.063" Score="12" ViewCount="3947" Body="&lt;p&gt;Under &lt;a href=&quot;https://earthscience.stackexchange.com/a/22479/6031&quot;&gt;this answer&lt;/a&gt; there's a comment:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;I am not aware of any location having its hottest temperature in winter...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and for &lt;em&gt;mid-to-polar latitude folks specifically&lt;/em&gt; we first learn that our summer is the hottest and as we get older we learn that half of the planet has summer during our winter, and that folks near the equator may have more complex weather patterns than summer=hot, winter=cold.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Are there some places near &lt;em&gt;but not on&lt;/em&gt; the equator that are hottest in their winter and some that are hottest in their summer? Is there a map of this? Perhaps something indicating the hottest month of the year by color?&lt;/p&gt;&#xA;&lt;p&gt;I can imagine in the South it will be January and in the North it will be July (or similar, but near the equator I'm expecting a more complicated pattern, but have no idea what it would look like.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2021-07-05T21:47:20.513" Title="Are there some places near the equator that are hottest in their winter and some that are hottest in their summer? Is there a map of this?" Tags="|meteorology|seasons|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22493" PostTypeId="2" ParentId="22492" CreationDate="2021-07-04T03:39:36.040" Score="19" Body="&lt;p&gt;Tropical climates usually aren't subject to typical extratropical seasons and are instead characterized by rainy/dry seasons.  However, if you define the &amp;quot;summer&amp;quot; and &amp;quot;winter&amp;quot; using the typical nothern/southern hemisphere convention, rather than by local vernacular in the region, then the answer is yes.  According to the &lt;a href=&quot;https://www.ncdc.noaa.gov/data-access/land-based-station-data/land-based-datasets/global-historical-climatology-network-monthly-version-4&quot; rel=&quot;noreferrer&quot;&gt;Global Historical Climatology Network–monthly (GHCNm) dataset&lt;/a&gt;, a set of monthly climate summaries from thousands of weather stations around the world, there are areas in South America near the equator that appear to satisfy this condition. However, these places are really just warm all year long and have little difference in the hottest and coolest months.  See below images from &lt;a href=&quot;https://twitter.com/Climatologist49/&quot; rel=&quot;noreferrer&quot;&gt;Brian Brettschneider&lt;/a&gt;.  I think &lt;a href=&quot;https://en.wikipedia.org/wiki/Balsas,_Maranh%C3%A3o&quot; rel=&quot;noreferrer&quot;&gt;Balsas, Maranhao, Brazil&lt;/a&gt; is a good candidate:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UZ25W.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UZ25W.png&quot; alt=&quot;warmest day of year&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;...&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hFRhI.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hFRhI.png&quot; alt=&quot;coldest day of year&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2021-07-05T21:47:20.513" LastActivityDate="2021-07-05T21:47:20.513" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="22494" PostTypeId="1" AcceptedAnswerId="22495" CreationDate="2021-07-04T11:00:08.683" Score="1" ViewCount="82" Body="&lt;p&gt;I recently read about safe mud window - it states that the mud pressure in a wellbore should be high enough to prevent well collapse, and should not exceed the formation's fracture pressure. But consider deep mine tunnels - there is no &amp;quot;mud pressure&amp;quot; at all, just air. A mine's depth could exceed 3km, and its tunnels withstand this overburden rock mass. So why do wellbores collapse with a lack of pressure, but deep mines do not?&lt;/p&gt;&#xA;" OwnerUserId="22916" LastEditorUserId="22916" LastEditDate="2021-07-04T13:38:56.013" LastActivityDate="2021-07-04T15:46:57.180" Title="Why should wellbores be supported by pressure, but not mine tunnels?" Tags="|geophysics|mining|pressure|drilling|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22495" PostTypeId="2" ParentId="22494" CreationDate="2021-07-04T15:46:57.180" Score="1" Body="&lt;p&gt;Drilling mud is only used when drilling for fluids that are pressurized such as oil, gas and sometimes water. It is not used when drilling for minerals such as gold, iron ore, copper.&lt;/p&gt;&#xA;&lt;p&gt;Exploratory drilling minerals will use a combination of:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://www.drillpowerqld.com.au/Explain-to-me-What-is-air-rotary-drilling-and-why-do-we-use-it-bgp4166.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rotary air blast drilling&lt;/a&gt; (RAB) - where compressed air is forced&#xA;through the drill steel to flush drill cutting out of the hole&#xA;between the drill steel and the wall of the hole.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://castledrill.com/an-introduction-to-reverse-circulation-drilling/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reverse circulation&lt;/a&gt; drilling (RC) - where the air flow is&#xA;opposite to RAB holes. Compressed air is forced between the gap&#xA;between the drill steel and the wall of the hole. The drill cutting&#xA;exit the hole through the hollow center of the drill steel.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Exploration_diamond_drilling&quot; rel=&quot;nofollow noreferrer&quot;&gt;Diamond drilling&lt;/a&gt; - uses cylindrical drill bit with diamonds in&#xA;the cutting edge to collect a solid sample of rock from the drill&#xA;hole.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Because rock containing minerals rarely contains pressurized fluids, if the rock is competent the drill holes remain open.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://file:///C:/Users/User/Downloads/Documents/Chapter%206.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Drilling for oil and gas&lt;/a&gt; and sometimes water requires the drill steel to pierce rock that is pressurized by fluids. To counter the pressure of the fluids so the hole remains open, such holes require drilling mud.&lt;/p&gt;&#xA;&lt;p&gt;The other reasons for using mud when drilling for oil and gas are:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;•To lubricate the drill bit.&lt;/p&gt;&#xA;&lt;p&gt;•To remove drilled material away from the drill bit and transport them to the surface.&lt;/p&gt;&#xA;&lt;p&gt;•To counteract the fluid pressure in the rock.&lt;/p&gt;&#xA;&lt;p&gt;•Stabilize the wellbore&lt;/p&gt;&#xA;&lt;p&gt;If a well could be drilled without a drilling fluid, formation fluids, which are under their fluid pressure,would  spurt  out  of  the  borehole  (blow-out).  The  density  of  the  drilling  fluid  used  in  a  particular borehole is designed to generate a drilling mud pressure (due to the weight of the drilling mud in the borehole above a given depth) that counteracts the fluid pressure in the formation and prevent blow-outs. This is usually successful, but because sudden increases in over pressure can be encountered the drilling  mud  pressure  is  kept  higher  than  necessary  as  a  safety  feature.  When  the  mud  pressure  is greater than the formation fluid pressure, the well is said to be over-balanced.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Mine and civil engineering tunnels are not simply dug and left to stay as they have been excavated.&lt;/p&gt;&#xA;&lt;p&gt;Civil engineering tunnels can be lined with concrete, as can mine shafts. Mining tunnels tend not to be concrete lined due to the cost of the concrete. Instead they are reinforced by using &lt;a href=&quot;https://en.wikipedia.org/wiki/Rock_bolt&quot; rel=&quot;nofollow noreferrer&quot;&gt;rock bolts&lt;/a&gt;, &lt;a href=&quot;https://www.industrysearch.com.au/cable-bolt-mining/p/112340&quot; rel=&quot;nofollow noreferrer&quot;&gt;cable bolts&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Shotcrete&quot; rel=&quot;nofollow noreferrer&quot;&gt;shotcrete&lt;/a&gt;, as required.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-07-04T15:46:57.180" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22496" PostTypeId="2" ParentId="22481" CreationDate="2021-07-04T15:52:48.457" Score="3" Body="&lt;p&gt;Weather prediction has been (&lt;a href=&quot;https://www.ecmwf.int/en/newsletter/166/news/forecast-performance-2020&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ecmwf.int/en/newsletter/166/news/forecast-performance-2020&lt;/a&gt;) and will be getting better, but it can only get so good. Even if we build the perfect weather model and feed it with the perfect initial and boundary conditions (practically impossible at the moment), the forecasts will still be overshadowed by chaos and/or stochasticity at some spatial and temporal scales. Moist convection and precipitation are particularly prone to this, due to the involvement of a zoo of processes (inter)acting at scales from nanometres to kilometres and from seconds to days. Running the exact same model two times with slightly different initial conditions may produce two equally-plausible forecasts that disagree on whether it will rain or not in your neighborhood in 12 hours from now. The big forecast centres nowadays reflect on this inherent uncertainty by producing many forecasts at a time. In this regard, you are better off looking at probabilistic forecasts (e.g., 70% chance of rain) rather than deterministic (e.g., 25mm of rain) or categorical (e.g., rain vs no rain) ones. When you then assess the model performance, you should do that in a probabilistic sense as well (when the forecast says 70% chance of rain, does it actually rain 70% of the times?).&lt;/p&gt;&#xA;&lt;p&gt;Unfortunately, even probabilistic forecasts fail at times and produce a range of outcomes that is far from what was actually observed. Associated with that, one should keep in mind that not all regions in the globe and weather regimes are equally predictable. Rainfall associated with a (synoptic-scale) cyclone and its organised frontal systems is easier to predict than rainfall associated with (small-scale) isolated thunderstorms. Wind over a large plain is easier to predict than wind over a mountainous region.&lt;/p&gt;&#xA;&lt;p&gt;I am not sure about the SMHI model, but I suppose it is a competent high-resolution regional model focused on Scandinavia. If they do not issue probabilistic forecasts, you can look at global models like ECMWF, GFS, ICON. They are not tuned to Sweden, but this is not necessarily bad; an ensemble of forecasts (from a single or several models) will surely give you a better overview of the possible outcomes.&lt;/p&gt;&#xA;&lt;p&gt;Regarding the short-term predictions of the next 0-6 hours, we are in the nowcasting realm (&lt;a href=&quot;https://public.wmo.int/en/resources/bulletin/nowcasting-guidelines-%E2%80%93-summary&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://public.wmo.int/en/resources/bulletin/nowcasting-guidelines-–-summary&lt;/a&gt;). For this range, you should primarily look at real-time observations from radars, satellites, lightning networks, surface stations, etc; especially if there are enough of those near you. Some weather apps/services make a synthesis of these observations and extrapolate into the near future so that people know what actually comes their way.&lt;/p&gt;&#xA;" OwnerUserId="21690" LastActivityDate="2021-07-04T15:52:48.457" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22497" PostTypeId="2" ParentId="22492" CreationDate="2021-07-04T15:55:56.930" Score="6" Body="&lt;p&gt;The temperate concepts of winter and summer don't quite apply to the tropics, the region between the Tropic of Capricorn and the Tropic of Cancer. That region experiences two maxima and two minima per year in terms of top of the atmosphere (TOA) insolation. The solstices mark the times at which TOA insolation is at a minimum at the equator. The equinoxes are when TOA insolation is at a maximum at the equator. At or near the equator, it is cloudiness and rainfall (or lack thereof) that dictate when the coolest and warmest months occur.&lt;/p&gt;&#xA;&lt;p&gt;Cloudiness and rainfall can greatly reduce insolation and temperatures at the surface. The Intertropical Convergence Zone (ITCZ) provides a lot of cloudiness and rainfall in the tropics. The ITCZ moves north and south and back again over the course of a year. The northward motion of the ITCZ in Northern Hemisphere summer explains why the Sahel and Central America do not experience their highest temperatures in July or August.&lt;/p&gt;&#xA;&lt;p&gt;The ITCZ reaches its northernmost location in those months. Coupling this with the fact that TOA insolation is at a minimum on the June solstice at the equator, it should not be surprising that parts of Brazil that are south of the equator experience their warmest temperatures in July or August.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2021-07-04T15:55:56.930" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22498" PostTypeId="1" CreationDate="2021-07-04T16:11:33.847" Score="4" ViewCount="59" Body="&lt;p&gt;I teach a class on my state's history to middle school students. Our textbooks do not cover much historical geology, but its a subject students are fascinated in, and feel needs to be added.&lt;/p&gt;&#xA;&lt;p&gt;I want to present my students with a basic understanding of (1) how the state initially formed (2) the major geological changes that occurred since then, and then (3) show how these impacted climate, flaura, and fauna changes.&lt;/p&gt;&#xA;&lt;p&gt;I'm struggling to match up the information from the geologists, paleontologists, and archaeologists in this way. The paleontology books, for instance, speak of aquatic dinosaurs during the Triassic period, then I turn to geology books during that time, and there are no mention of water levels anywhere...and similar issues where the information doesn't seem to match, or at least, don't provide a comprehensive &amp;quot;big picture&amp;quot; of what is going on.&lt;/p&gt;&#xA;&lt;p&gt;This leads me to wonder if there is any source that presents a comprehensive view of changes to the World (or at least North America) across time? This could be an Atlas, detailed book of maps, on-line time line, or maybe even some software modelling and showing the changes, just something to help visualize what happened to a layperson.&lt;/p&gt;&#xA;" OwnerUserId="17645" LastActivityDate="2021-07-04T16:11:33.847" Title="Is there any source that shows all of Earth's terrain changes from Pangea to present?" Tags="|plate-tectonics|earth-history|resources|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22499" PostTypeId="2" ParentId="630" CreationDate="2021-07-05T04:02:49.453" Score="0" Body="&lt;p&gt;If it was produced over hundreds of millions of years, it must be at a very low rate, otherwise we would be up to our armpits in the stuff.&lt;/p&gt;&#xA;&lt;p&gt;Unless it was consumed by bacteria, in which case the atmosphere's oxygen would be used up.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2021-07-05T04:02:49.453" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22500" PostTypeId="2" ParentId="22490" CreationDate="2021-07-05T06:07:19.490" Score="6" Body="&lt;p&gt;The National Weather Service actually has a nice &lt;a href=&quot;https://www.weather.gov/about/forecast-process&quot; rel=&quot;noreferrer&quot;&gt;forecast summary page&lt;/a&gt; that answers your question:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Our scientists thoroughly review current observations using technology such as radar, satellite and data from an assortment of ground-based and airborne instruments to get a complete picture of current conditions. Forecasters often rely on computer programs to create what’s called an “analysis,” which is simply a graphical representation of current conditions. Once this assessment is complete and the analysis is created, forecasters use a wide variety of numerical models, statistical and conceptual models, and years of local experience to determine how the current conditions will change with time. Numerical modeling is fully ingrained in the forecast process, and our forecasters review the output of these models daily. Often, the models yield different results, and in these circumstances, forecasters will determine which models perform best for the given situation or seek a blended solution.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;They also have a good &amp;quot;&lt;a href=&quot;https://www.weather.gov/about/nws&quot; rel=&quot;noreferrer&quot;&gt;About Page&lt;/a&gt;&amp;quot; that discusses the regional offices and a &lt;a href=&quot;https://www.weather.gov/rah/virtualtourfcstcreation&quot; rel=&quot;noreferrer&quot;&gt;Virtual Tour of the Forecast Process&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2021-07-05T06:07:19.490" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22501" PostTypeId="2" ParentId="16596" CreationDate="2021-07-05T13:54:14.663" Score="2" Body="&lt;p&gt;I think Camilo Rada's answer is the one to follow if you want to do anything serious with the data.&lt;/p&gt;&#xA;&lt;p&gt;However, to answer the question a bit more directly, if you want to use actual equations then an alternative that should work just fine if you are looking at just the Holocene (maybe all of the Quaternary?) is to use the original tables from André Berger&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://journals.ametsoc.org/view/journals/atsc/35/12/1520-0469_1978_035_2362_ltvodi_2_0_co_2.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://journals.ametsoc.org/view/journals/atsc/35/12/1520-0469_1978_035_2362_ltvodi_2_0_co_2.xml&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The equations are described at the beginning and &amp;quot;decompose&amp;quot; the orbital mechanics into a sums of sinusoids:&lt;/p&gt;&#xA;&lt;p&gt;ε = ε* + ∑ Aicos(fit + δi)&#xA;e = e0 + ∑ Ei cos(λit + φi)&#xA;e sin( ω ) = ∑ Pi sin(αit + ζi)&lt;/p&gt;&#xA;&lt;p&gt;These values are read in from the tables provided in the paper. If you're just playing around, the even just summing the top 3 terms for each orbital parameter will give you nice looking results.&lt;/p&gt;&#xA;&lt;p&gt;However, as the other answer illustrates, even though the final result looks like a rather simple sinusoid, in reality is has a lot of secondary oscillating terms. You look at the tables and the first 5+ terms are of a &amp;quot;significant&amp;quot; amplitude. So the motion is not just a couple of dominant frequencies with some noise overlay.&lt;/p&gt;&#xA;&lt;p&gt;Again, this is all fun and educational, but if you're doing serious work then you probably want to get the full Laskar tables&lt;/p&gt;&#xA;" OwnerUserId="22874" LastActivityDate="2021-07-05T13:54:14.663" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22502" PostTypeId="1" CreationDate="2021-07-05T16:16:43.370" Score="6" ViewCount="333" Body="&lt;p&gt;I'm looking for a world map of wind gust climatology data, with the specific purpose of being used for coarse comparison of building design loads, with a consistent metric regardless of location.&lt;/p&gt;&#xA;&lt;p&gt;Ideally it would be very similar to what's used in building codes, such as &amp;quot;basic wind speed&amp;quot; in ASCE 7 for the US &amp;amp; International Building Code, and comparable codes for other regions:  a contour map or heat map of  the max value with a 50-year return period (or similar statistic, with various levels for different risk profiles).  See the US map &lt;a href=&quot;https://codes.iccsafe.org/content/IBC2018/chapter-16-structural-design#IBC2018_Ch16_Sec1609.3&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; and one for India (below, &lt;a href=&quot;https://skyciv.com/docs/tech-notes/loading/is-875-3-wind-load-calculation-example/&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;).&#xA;&lt;a href=&quot;https://i.stack.imgur.com/SGsVT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SGsVT.png&quot; alt=&quot;map of IS 875-3 wind loads&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I have found world maps of other climatology and extreme value data, but none for high-percentile gusts. Most of the global wind data maps are oriented towards power generation.  I'm not sure what resolution I need, probably 1- or 2- degree would be fine, but it would have to come from a higher-resolution source to capture local maxima.&lt;/p&gt;&#xA;&lt;p&gt;What I've already tried/considered:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The closest I've found is &lt;a href=&quot;https://www.dlubal.com/en-US/solutions/online-services/snow-load-wind-speed-and-seismic-load-maps&quot; rel=&quot;nofollow noreferrer&quot;&gt;this Dlubal seismic/wind/snow load map explorer&lt;/a&gt; - which is super useful and impressive, but doesn't fully serve my need because it's (a) a limited-click web app of a paid program, not a static map or set of maps, (b) does not have all countries, and (c) uses local codes which vary, making initial comparisons hard -although they would be needed eventually.&lt;/li&gt;&#xA;&lt;li&gt;I would make my own if I had more time to spend.  The data is there at a useful level in several climate re-analysis products, such as MERRA-2 and ERA-5.  In particular the Copernicus CDS not only lets you slice and download datasets, but even &lt;a href=&quot;https://cds.climate.copernicus.eu/cdsapp#!/toolbox&quot; rel=&quot;nofollow noreferrer&quot;&gt;do the analysis online&lt;/a&gt;.  I tried to use Panoply to create a view for a single timestep, but simply don't have the experience and time to efficiently do the 24 hr x 365 day x 30 year x 10&lt;sup&gt;6&lt;/sup&gt; gridpoints analysis.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Any pointers are welcome (including on this, my first StackExchange question). Thanks.&lt;/p&gt;&#xA;" OwnerUserId="22931" LastEditorUserId="24481" LastEditDate="2021-09-27T10:20:00.873" LastActivityDate="2021-09-27T10:20:00.873" Title="Is there a global map of wind design loads or wind gust climatology?" Tags="|climate|wind|mapping|data-analysis|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22503" PostTypeId="2" ParentId="22490" CreationDate="2021-07-05T23:26:29.700" Score="7" Body="&lt;p&gt;The Virtual tour is good, and I don't know why that wasn't an accepted answer. So I'll throw my answer into the ring. I'll recommend you try the &lt;a href=&quot;https://www.meted.ucar.edu/bom/intro_nwp/index.htm&quot; rel=&quot;noreferrer&quot;&gt;NWP and Forecasting Comet module&lt;/a&gt; (it's free if to get an account). That'll probably help more than my answer, which is based around the forecasting classes that I took and my experience as a forecaster in the university's student-run weather service.&lt;/p&gt;&#xA;&lt;p&gt;From the outside, the forecast process is a very mysterious thing. But in reality it is not. Though, it is highly a subjective task and is subject to some degree of variation per person (hence some people are better forecasters than others). It also takes a lot of time to do it right. Here is my pattern if I want to be rigorous.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Know where I am forecasting for.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Location is important. What do I know about the climatology. Climatology can give a &amp;quot;first guess&amp;quot; on the range of values that can be reasonably considered. The previous day's weather can also be a good first guess. If I am well acquainted with the area, then this becomes a shorter and shorter step.&lt;/p&gt;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;Start with observations.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;What is happening now? What is reality saying? The amount of space that is looked at needs to be proportionate to the forecast time.&lt;/p&gt;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;Make inferences on the current state and causes of weather features.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;What patterns are seen? Was map analysis done? Are there certain areas that are colder than others? Are there places that have clouds and others that don't have clouds? What does the radar say? Why, why why why why? If you know the mechanisms that are generating weather now, then you can understand how they might evolve.&lt;/p&gt;&#xA;&lt;ol start=&quot;4&quot;&gt;&#xA;&lt;li&gt;Examine how the weather models have started.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Before you use a weather model, you should understand it. Garbage in=garbage out, &lt;em&gt;sometimes&lt;/em&gt;. How well did the model do today? If it is overpredicting temperature right now, will it continue overpredicting the temperature? Will the errors that occurred upstream yesterday occur today?&lt;/p&gt;&#xA;&lt;ol start=&quot;5&quot;&gt;&#xA;&lt;li&gt;Look at how the weather models progress. Question if it aligns with my knowledge and experience.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Taking a model at face value might work for research purposes (unless you are researching the model itself), but shouldn't be done on a practical level or in a rush. What does Model Output Statistics (MOS) say?&lt;/p&gt;&#xA;&lt;ol start=&quot;6&quot;&gt;&#xA;&lt;li&gt;Choose the right numbers or features.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;This is probably the step that requires the least amount of explanation. Though the more intricate the type of forecast, the harder and harder this becomes. Does it actually require numbers, or is there some sort of GIS software (like for hurricane trajectory or lightning forecast)?&lt;/p&gt;&#xA;&lt;ol start=&quot;7&quot;&gt;&#xA;&lt;li&gt;Verify&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;This can't be stated enough. You must verify how well you did. Decisions need to be made on how the forecast will be verified. What data sources do you know of for verification? If I could move this up to number 1 and still have this make sense, I would. Because this is what you should start off with. This actually goes part and parcel with starting with observations, since observations are what you start a forecast with. Understand the processes of why your forecast was off. This will serve you in the future and in the next forecast.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-07-05T23:26:29.700" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22504" PostTypeId="1" CreationDate="2021-07-06T09:10:00.893" Score="3" ViewCount="308" Body="&lt;p&gt;I am a software developer, and I am testing a DateTime converter right now. I need to see if the conversion works when a timezone is transitioning from daylight saving time to its standard time at the last possible timeframe in the transition day, i. e 23:00 to 00:00 happens twice, the former with DST on, and the latter with ST on. Is there ever such an occurrence in the future or past? Is there such a dataset I can query this specifically?&lt;/p&gt;&#xA;" OwnerUserId="11876" LastEditorUserId="11876" LastEditDate="2021-07-06T15:05:27.400" LastActivityDate="2021-07-16T23:33:44.387" Title="Is there any DST to ST transition happening at the end of the day?" Tags="|time|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22505" PostTypeId="2" ParentId="22504" CreationDate="2021-07-06T14:51:58.313" Score="8" Body="&lt;p&gt;Per &lt;a href=&quot;https://en.wikipedia.org/wiki/Daylight_saving_time_by_country&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;, several countries switch to daylight savings time at midnight. Time jumps from midnight to 1:00 AM in these countries on the date of the switch to daylight savings time. Only Chile, Iran, Lebanon, Palestine, Paraguay, and Syria switch back to standard time at midnight. Time jumps from midnight to 11:00 PM in these countries on the date of the switch from daylight savings time to standard time.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="20607" LastEditDate="2021-07-16T23:33:44.387" LastActivityDate="2021-07-16T23:33:44.387" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22506" PostTypeId="1" CreationDate="2021-07-07T00:53:38.387" Score="8" ViewCount="1636" Body="&lt;p&gt;I am reading studies about the age of the earth and U-238 to Pb-206 comes up a lot.&lt;/p&gt;&#xA;&lt;p&gt;My question is:&lt;/p&gt;&#xA;&lt;p&gt;In meteorites, or really anywhere, is lead 206 natural or does it always come from radioactive decay?&lt;/p&gt;&#xA;&lt;p&gt;If it is natural is the potential quantity of that daughter isotope capable of skewing the results and predicted age? So if there was already some of that isotope there it would seem as if it had been decaying for longer and therefore thought to be older?&lt;/p&gt;&#xA;" OwnerUserId="22946" LastEditorUserId="22648" LastEditDate="2021-07-07T05:59:25.353" LastActivityDate="2021-07-07T05:59:25.353" Title="Do lead 206 and other daughter isotopes occur naturally?" Tags="|geochemistry|dating|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22507" PostTypeId="2" ParentId="22506" CreationDate="2021-07-07T02:13:21.417" Score="13" Body="&lt;p&gt;While lead 206 does occur naturally, unless a zircon (a zirconium silicate crystal) is contaminated with lead or has been around a long time, it will contain no lead. Zirconium, uranium, and thorium have similar chemistries. Lead has a dramatically distinct chemistry. The chemical reactions that form zircons can accommodate uranium or thorium replacing zirconium, but not lead.&lt;/p&gt;&#xA;&lt;p&gt;Assuming no contamination, all of the lead in a zircon could only have resulted from radioactive decay. This is an overly strong assumption. Researchers do have to address the issue of possible contamination. But the basic concept remains: Zircons cannot accommodate lead.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2021-07-07T02:13:21.417" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22508" PostTypeId="2" ParentId="22506" CreationDate="2021-07-07T05:33:12.877" Score="9" Body="&lt;p&gt;The four &lt;a href=&quot;https://en.wikipedia.org/wiki/Isotopes_of_lead#Lead-208&quot; rel=&quot;noreferrer&quot;&gt;stable isotopes of lead&lt;/a&gt; and their relative abundance on Earth are: &lt;sup&gt;204&lt;/sup&gt;Pb (1.4%), &lt;sup&gt;206&lt;/sup&gt;Pb (24.1%), &lt;sup&gt;207&lt;/sup&gt;Pb (22.1%) and &lt;sup&gt;208&lt;/sup&gt;Pb (52.4%). Lead-204 is a &lt;a href=&quot;https://en.wikipedia.org/wiki/Primordial_nuclide&quot; rel=&quot;noreferrer&quot;&gt;primordial nuclide&lt;/a&gt; and is not a &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiogenic_nuclide&quot; rel=&quot;noreferrer&quot;&gt;radiogenic nuclide&lt;/a&gt;.  &lt;sup&gt;206&lt;/sup&gt;Pb, &lt;sup&gt;207&lt;/sup&gt;Pb, and &lt;sup&gt;208&lt;/sup&gt;Pb form as part of the radioactive decay chains of Uranium and Thorium and they also occur as &lt;a href=&quot;https://en.wikipedia.org/wiki/Primordial_nuclide&quot; rel=&quot;noreferrer&quot;&gt;primordial nuclides&lt;/a&gt; that were made in supernovae.  As &lt;a href=&quot;https://earthscience.stackexchange.com/users/239/david-hammen&quot;&gt;David Hammen&lt;/a&gt; points out, &lt;a href=&quot;https://en.wikipedia.org/wiki/Uranium%E2%80%93lead_dating&quot; rel=&quot;noreferrer&quot;&gt;uranium-lead dating&lt;/a&gt; is done with &lt;a href=&quot;https://en.wikipedia.org/wiki/Zircon&quot; rel=&quot;noreferrer&quot;&gt;zircons&lt;/a&gt;, and they reject the inclusion of lead when forming.  So, usually any lead in a &lt;a href=&quot;https://en.wikipedia.org/wiki/Zircon&quot; rel=&quot;noreferrer&quot;&gt;zircon&lt;/a&gt; is from radioactive decay.  &lt;a href=&quot;https://en.wikipedia.org/wiki/Zircon&quot; rel=&quot;noreferrer&quot;&gt;Zircon&lt;/a&gt; is commonly found in igneous rocks, metamorphic rocks and sedimentary rocks.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="2470" LastEditDate="2021-07-07T05:50:19.967" LastActivityDate="2021-07-07T05:50:19.967" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22509" PostTypeId="1" CreationDate="2021-07-07T17:51:17.047" Score="5" ViewCount="211" Body="&lt;p&gt;I am making a global social media website for farmers and gardeners which can be used to share information about plant varieties. This sharing is done via so called garden journals.&#xA;In a garden journal different things related to growth and crop performance can be recorded such as the sow date, the time it took until the seeds germinated or the plant flowered and when the first moment of harvest was. The author of the garden journal can also record the bugs, diseases and animals that interacted with the plant(s).&lt;/p&gt;&#xA;&lt;p&gt;I would like people from different places in the world to use the garden journals of people who share the same soiltype as them. In order to make the search for these garden journals more easy i want to use a soil classification system. When starting a garden journal the author can enter the soiltype of the ground he or she will be growing the plants on. When the garden journal is finished other people who share the same soiltype can easily find this journal by performing a search based on that particular soiltype.&lt;/p&gt;&#xA;&lt;p&gt;There are two major soiltype classifications in the world, namely the one from USDA which has 12 major soiltypes and the one from FAO/UNESCO which consists of far more different soiltypes.&lt;/p&gt;&#xA;&lt;p&gt;I would like to hear your opinion about which of the two systems would be the best for my usecase. I would also like to know if the data of any of these 2 systems is accessible via an API. In other words, is there a website that allows me to find the soiltype of a  country, province or city/village via an API call?&lt;/p&gt;&#xA;" OwnerUserId="18140" LastActivityDate="2021-07-07T17:51:17.047" Title="USDA soil classification vs FAO/UNESCO soil classification" Tags="|soil|soil-science|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22512" PostTypeId="2" ParentId="15427" CreationDate="2021-07-08T21:52:20.433" Score="1" Body="&lt;p&gt;It took me a while to get it (and I'm not a geologist or petroleum engineer or anything, just someone who knows basic physics and has been reading a geology textbook), but I think I understand Erik's answer: It's based on buoyancy.&lt;/p&gt;&#xA;&lt;p&gt;Consider a column of permeable rock and soil that has a zone of aeration above a zone of saturation. (I'm gonna talk about water, but it would also work for oil or air or any other fluid less dense than the local rock/soil.) If any weight from the soil/rock were pushing down on the water in the zone of saturation, it would just push the water up and out of the way and raise the water table, while lowering some of the rock/soil. This is because the rock/soil is denser than water, so gravitational potential energy goes down when rock/soil goes down and pushes an equal volume of water up.&lt;/p&gt;&#xA;&lt;p&gt;Water with an impermeable layer above it can support some of the weight of the rock because the buoyancy force this would create can't push the water up through the impermeable layer. If a hole were made in said impermeable layer, displaced water could move up through that hole to allow the supported rock to settle a little lower (which is how artesian wells work).&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;If the water is supporting some of the weight of the rock, this fraction of that weight (this fraction of the lithostatic pressure) will have to be supported by pressure that is locally (approximately) hydrostatic (equal in all directions), because that's the only way stationary fluids can exert pressure. This means the water pressure can also push sideways, which seems like it should matter when strata are tilted or curved so that part of the permeable bed is open to the surface while the rest is overlied by an impermeable bed, as in a typical aquifer, and it does:&lt;/p&gt;&#xA;&lt;p&gt;As you move sideways (on a surface of constant gravitational potential(pot. energy÷mass)/geopotential) the hydrostatic pressure in the water must be stay constant; otherwise, the water would flow sideways to equalize it. (Actually, this isn't entirely true, as can be determined from my geology textbook, which notes that &amp;quot;pores ... provide resistance to flow&amp;quot;, related to permeability of the rock/soil and viscosity of the fluid I guess, and that &amp;quot;pressure is lost through fractures (leaks)&amp;quot;, presumably in the &amp;quot;imperable&amp;quot; layers, but it's a good starting approximation.) As you move down through the water, the pressure goes up according to how much more weight (weight of the water and possibly a bit of the rock) the water at that point needs to support. (Reverse as you go up.)&lt;/p&gt;&#xA;&lt;p&gt;Now, remember that the water at the top of the water table in the area with a zone of aeration above it, and atmosphere above that, cannot support any lithostatic pressure. As you go straight down from here, let's assume only the weight of the water above being supported by the water, not any rock/soil. (I think that's true, but I'm not sure. In any case, it doesn't significantly affect my point if not.) As you move sideways from a point below the permable zone of aeration to a point below an impermable bed, the height of water above you has to drop from the height of the water table to the height of the bottom of the impermable bed (whenever this gets lower than the water table under air). More importantly, this generally means there is less weight of (contiguous) water pushing down on the water where you are. (I'm just noticing that, since much or most of the volume underground is rock/soil, volume and therefore weight of water in a column is only proportional to height in rock/soil of constant porosity, but that approximation basically works within a single permable bed.) However, the hydrostatic pressure must stay (approximately) the same. The only way to accomplish this is for the water to push up some of the rock and support enough of the lithostatic pressure to (approximately) equal the weight of water lost. (Actually resistance to flow and leaks mean the pressure goes slightly down as you move further sideways away from an area below air, which is why the &amp;quot;artesian-pressure surface&amp;quot;/&amp;quot;potentiometric surface&amp;quot; above an aquifer slopes down as you move away from the &amp;quot;recharge area&amp;quot; rather than being flat.)&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;I imagine a little extra complexity is added when your dealing with gasses rather than liquids (so the density of the fluid is highly dependent on the hydrostatic pressure it's under), when fluids are in motion rather than stationary, or when you consider the permeability of rocks quantitatively rather than as just &amp;quot;permeable&amp;quot; and &amp;quot;impermeable&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="22960" LastEditorUserId="22960" LastEditDate="2021-07-09T00:10:34.940" LastActivityDate="2021-07-09T00:10:34.940" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22513" PostTypeId="1" CreationDate="2021-07-09T00:16:16.023" Score="4" ViewCount="384" Body="&lt;p&gt;I’m a new prospector who was given the task of learning a GEM GSM-19T Proton Magnetometer. I’ve learned how to set it up, take base readings, and take walking surveys. However when setting up a base reading, I’ve been given the prompt to change the Datum number. The last user had it set to 53113.00. According to the manual, the Datum represents the offset or shift imposed to the Diurnal Correction. I want to upload the survey data to a computer but I want to make sure that this number is correct before doing so. I don’t know how to find this Datum, and am wondering if there’s a way I can figure it out.&lt;/p&gt;&#xA;" OwnerUserId="22968" LastActivityDate="2022-04-30T20:24:38.063" Title="How do I find the Datum (Diurnal Correction) number for a Magnetometer" Tags="|geomagnetism|data-analysis|rock-magnetism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22514" PostTypeId="1" CreationDate="2021-07-09T00:46:19.683" Score="6" ViewCount="78" Body="&lt;p&gt;A lot of papers mention that Normalized Difference Vegetation Index (NDVI) is sensitive to soil background such as bare soil. My question is what is the exact reason behind the impact of soil on NDVI?&lt;/p&gt;&#xA;&lt;p&gt;For example, in case of semi-arid environments where there is a lot of bare soil and sparse vegetation, NDVI is not recommended as it is influenced by bare soil. And that is why indices such as the Modified Soil Adjusted Vegetation Index (MSAVI) is used for such landscapes.&lt;/p&gt;&#xA;&lt;p&gt;Reference&lt;/p&gt;&#xA;&lt;p&gt;Qi, J., Chehbouni, A., Huete, A. R., Kerr, Y. H., &amp;amp; Sorooshian, S. (1994). A modified soil adjusted vegetation index. Remote sensing of environment, 48(2), 119-126.&lt;/p&gt;&#xA;" OwnerUserId="22887" LastEditorUserId="22887" LastEditDate="2021-07-09T20:36:11.530" LastActivityDate="2021-07-09T20:36:11.530" Title="Normalized Difference Vegetation Index sensitivity to soil" Tags="|remote-sensing|soil|vegetation|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22515" PostTypeId="1" CreationDate="2021-07-10T01:41:54.543" Score="3" ViewCount="90" Body="&lt;p&gt;Some context: I row every morning, and due to my rowing club's proximity to a large lake, it is often very windy and rough (which builds character, according to the coaches). I noticed that as we row under bridges, the water seems to &amp;quot;speed up&amp;quot; and the waves grow in height. A similar effect is noted near the breakwaters close to shore, where an area of rough and fast waters seems to be created.&lt;/p&gt;&#xA;&lt;p&gt;I'm not sure if this is fitting in the Earth Science SE, or if this is too broad or elementary, but I would like to know what causes this!&lt;/p&gt;&#xA;&lt;p&gt;EDIT: The bridge in question has two rows of three pillars (similar to the below image, except closer together and made of steel) parallel to each other, we pass between the opening.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/F0YQw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/F0YQw.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17398" LastEditorUserId="17398" LastEditDate="2021-07-10T12:35:56.190" LastActivityDate="2021-07-15T03:28:40.210" Title="The effect of enclosed channels and breakwaters on wave height and velocity" Tags="|oceanography|waves|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22518" PostTypeId="2" ParentId="2566" CreationDate="2021-07-10T13:03:52.667" Score="6" Body="&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/s43247-020-00071-w&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; is a brand new (January 2021) study from Nature.&lt;/p&gt;&#xA;&lt;p&gt;It proposes that the Sahara has not been the main source of dust for the Amazon for the past 7,500 years of Holocene, but rather dust from North and South Africa, the Andes, and Southern South America.&lt;/p&gt;&#xA;" OwnerUserId="22976" LastEditorUserId="106" LastEditDate="2021-07-12T08:35:43.957" LastActivityDate="2021-07-12T08:35:43.957" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22519" PostTypeId="1" CreationDate="2021-07-11T21:32:58.940" Score="2" ViewCount="151" Body="&lt;p&gt;When radiometric dating, would water affect the measured age of old rocks ?&lt;/p&gt;&#xA;&lt;p&gt;Specifically would water affect &lt;strong&gt;Uranium-238&lt;/strong&gt; to &lt;strong&gt;Lead-206&lt;/strong&gt; dating of Zircon crystals?&lt;/p&gt;&#xA;&lt;p&gt;Would it affect the lead since it’s slightly soluble in water?&lt;/p&gt;&#xA;" OwnerUserId="22946" LastEditorUserId="22648" LastEditDate="2021-07-12T08:40:48.553" LastActivityDate="2021-07-14T10:52:35.840" Title="Does water affect radiometric dating?" Tags="|water|rocks|dating|geochronology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22521" PostTypeId="1" CreationDate="2021-07-12T14:15:30.743" Score="4" ViewCount="132" Body="&lt;p&gt;I am trying to understand climate tipping points better and I am looking for a place to ask the following question. If Earth Science SE isn't the right place, a recommendation of a better place would be welcome.&lt;/p&gt;&#xA;&lt;p&gt;Let me refer to the paper &lt;a href=&quot;https://arxiv.org/pdf/1805.00534.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Analysis and Predictability for Tipping Points with&#xA;Leading-Order Nonlinear Terms&lt;/a&gt; and consider the dynamical system described by this set of stochastic differential equations:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\dot{T} = f(C,\dot{C}) + \sigma(T)\cdot\dot{W}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\dot{C} = g(T) + \varepsilon$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;with &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; the mean global temperature, &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; the mean concentration of atmospheric carbondioxide, &lt;span class=&quot;math-container&quot;&gt;$\sigma$&lt;/span&gt; the &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt;-dependent noise level, &lt;span class=&quot;math-container&quot;&gt;$W$&lt;/span&gt; a one-dimensional Brownian motion, and &lt;span class=&quot;math-container&quot;&gt;$\varepsilon$&lt;/span&gt; the (small) anthropogenic increase of atmospheric carbondioxide.&lt;/p&gt;&#xA;&lt;p&gt;The function &lt;span class=&quot;math-container&quot;&gt;$f(C,\dot{C})$&lt;/span&gt; captures the increase of &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; by increasing &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt;. When doubling of &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; compared to &lt;span class=&quot;math-container&quot;&gt;$C_0 = 200\ \textsf{ppm}$&lt;/span&gt; in 1850 or so results in an increase of &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; by &lt;span class=&quot;math-container&quot;&gt;$3°C$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$f(C,\dot{C})$&lt;/span&gt; takes the form&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$f(C,\dot{C}) = 3\cdot\dot{C}/C$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The function &lt;span class=&quot;math-container&quot;&gt;$g(T)$&lt;/span&gt; captures the fact, that the oceans emit an increasing net amount of &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt;, depending on temperature. Let's assume that&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$g(T) = \gamma\cdot(T - T_0)$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;with &lt;span class=&quot;math-container&quot;&gt;$T_0$&lt;/span&gt; the mean global temperature in 1850 or so.&lt;/p&gt;&#xA;&lt;p&gt;The function &lt;span class=&quot;math-container&quot;&gt;$\sigma(T)$&lt;/span&gt; captures the stochastic variance of temperature by internal variability which itself depends on the temperature. It may be assumed as&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\sigma(T) = \sigma_0 + \sigma_1\cdot(T - T_0).$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Question 1: Is the given form of &lt;span class=&quot;math-container&quot;&gt;$f(C,\dot{C})$&lt;/span&gt; roughly correct? Which functions &lt;span class=&quot;math-container&quot;&gt;$g(T)$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\sigma(T)$&lt;/span&gt; would be more realistic?&lt;/p&gt;&#xA;&lt;p&gt;Question 2: What can be said about attractors and long-term behaviour of this system?&lt;/p&gt;&#xA;&lt;p&gt;Question 3: Can this dynamical system give rise to tipping points?&lt;/p&gt;&#xA;" OwnerUserId="17431" LastEditorUserId="2470" LastEditDate="2021-07-12T15:26:45.270" LastActivityDate="2021-07-14T04:55:47.050" Title="Simple model that exhibits a climate tipping point" Tags="|climate-change|climate|climate-models|mathematics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22522" PostTypeId="2" ParentId="22481" CreationDate="2021-07-12T19:18:33.207" Score="0" Body="&lt;p&gt;Fun fact about rain percentages. When it says there is a 70% chance of rain, it does not always mean there is a 70% chance that you personally will get rained on. Weather stations are divided into sections. Depending on what app you use some predictions can be interpreted differently. But most of the time the 70% chance of rain means that there is nearly a 100% chance of rain in 70% of the area covered by the station that you are looking at. If there is less that a 100% of rain in the 70% area of coverage, a more reliable app will calculate the new average. I don’t know if there is a way to see the coverage area of any given station, but I can say that watching the radar predictions and coming up with your own prediction based on your exact location is much more reliable, albeit more time consuming.&lt;/p&gt;&#xA;" OwnerUserId="22979" LastActivityDate="2021-07-12T19:18:33.207" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22523" PostTypeId="1" CreationDate="2021-07-12T21:32:03.310" Score="4" ViewCount="95" Body="&lt;p&gt;Anecdotally, where I live in northern Europe, the weather seems to be stormier in winter, and this seems to be backed up by hard data. For example, &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0078323411500193?via%3Dihub&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/S0078323411500193?via%3Dihub&lt;/a&gt; discusses the meteorology of the North Sea, confirms storms are more prevalent in winter because of stronger winds. And &lt;a href=&quot;https://journals.sagepub.com/doi/full/10.1177/0022526619886061&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://journals.sagepub.com/doi/full/10.1177/0022526619886061&lt;/a&gt; analyzes British coastal trade over the last few centuries, confirms this pattern historically.&lt;/p&gt;&#xA;&lt;p&gt;But looking at weather patterns in other temperate regions, I seem to be seeing different results; Virginia and Japan are both said to have peak storm season in late summer, August-September.&lt;/p&gt;&#xA;&lt;p&gt;What's the reason for this difference? I can think of a few possible explanations:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The seasonality of storms is different at latitudes 35-40 compared to 50-55.&lt;/li&gt;&#xA;&lt;li&gt;It's different if you're on the west side of a large continent versus the east side.&lt;/li&gt;&#xA;&lt;li&gt;It's influenced by quirks of local geography such as the layout of the North Sea versus the Sea of Japan.&lt;/li&gt;&#xA;&lt;li&gt;The sources are talking about different things. Virginia and Japan are indeed stormiest in winter just like northern Europe if you talk about midrange storms driven by local meteorology; the peak in August-September is not for those kind of storms at all, but for hurricanes that come up from the tropics.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;What is the explanation for the differing patterns?&lt;/p&gt;&#xA;" OwnerUserId="7911" LastEditorUserId="22648" LastEditDate="2021-07-15T18:17:39.360" LastActivityDate="2021-07-15T18:17:39.360" Title="Does storm seasonality vary with latitude?" Tags="|meteorology|geography|tropical-cyclone|seasons|mesoscale-meteorology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22525" PostTypeId="2" ParentId="22416" CreationDate="2021-07-13T00:51:58.220" Score="6" Body="&lt;p&gt;By far most naturally occurring hydrates are methane hydrates. However, &lt;a href=&quot;https://www.sciencedirect.com/topics/chemical-engineering/gas-hydrate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dillon[1]&lt;/a&gt; documents hydration of other gases including carbon dioxide in some places such as the Gulf of Mexico:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Many gas hydrates are stable in the deep ocean conditions, but methane hydrate is by far the dominant type, making up &amp;gt;99% of gas hydrate in the ocean floor. The methane is almost entirely derived from microbial methanogenesis, predominantly through the process of carbon dioxide reduction. In some areas, such as the Gulf of Mexico, gas hydrates are also created by other thermogenically formed hydrocarbon gases and other clathrate-forming gases such as hydrogen sulfide and carbon dioxide. Such gases escape from sediments at depth, rise along faults, and form gas hydrate at or just below the seafloor, but on a worldwide basis these are of minor volumetric importance compared to methane hydrate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;There is no evidence from this that the carbon dioxide is in a purely binary hydrate, and the point is made that methane hydrates are by far more common. But yes, to at least a small degree carbon dioxide is hydrated in nature.&lt;/p&gt;&#xA;&lt;p&gt;One factor behind the limited occurrence of naturally occurring hydrates of carbon dioxide (and other common gases besides methane) is the solubility of the gas in liquid water. Gas hydrates exist in equilibrium with solutions of the gas in liquid water, so more soluble gases require higher  concentrations to form the hydrate (which may be thought of as a precipitate). &lt;a href=&quot;http://www.wiredchemist.com/chemistry/data/solubilities-gases&quot; rel=&quot;nofollow noreferrer&quot;&gt;This table&lt;/a&gt; reveals that on a mass basis, carbon dioxide is over 70 times as soluble as methane in water under ambient conditions; even accounting for the heavier molecular weight of carbon dioxide this is still a molar ratio of over 25 to 1. For hydrogen sulfide, also specifically mentioned in Ref. [1], the corresponding molar ratio is about 80 to 1 over methane. Two-carbon hydrocarbons such as ethane can also form hydrates and their solubility is closer to that of methane (allowing hydrate formation at lower concentrations than carbon dioxide or hydrogen sulfide), but these are less abundant gases in nature.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_dioxide_clathrate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Carbon dioxide hydrates are expected to be more widespread on Mars&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;1.&#xA;W. P. Dillon, in Robert A. Meyers, &lt;em&gt;Encyclopedia of Physical Science and Technology&lt;/em&gt;, Third Edition (2001).&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2021-07-25T14:17:58.360" LastActivityDate="2021-07-25T14:17:58.360" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22527" PostTypeId="2" ParentId="22523" CreationDate="2021-07-14T00:03:02.473" Score="3" Body="&lt;p&gt;It really depends on how you define storms. For tropical storms, there are some regions where they are not usually a threat. Likewise, for extratropical storms, there are latitudes where such things are not a concern (such as the tropics). The key to understanding the seasonality to such storms is to understand what controls the seasonality of what drives each.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Convective_instability#:%7E:text=In%20meteorology%2C%20convective%20instability%20or,disturbances%20dampen%20out%20and%20disappear.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Thunderstorms (broadly speaking) rely on a warm air over cooler air&lt;/a&gt;. During spring and summer that is more likely to happen. More in the spring, as the land and air near the land responds pretty quickly to the increase in radiation, whereas the air  further away from the land takes some time to adjust. Air that moves over a cool ocean current will tend to be cooler, so less thunderstorms will usually occur where land is downstream of cool water.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Extratropical_cyclone#:%7E:text=Extratropical%20cyclones%2C%20sometimes%20called%20mid,over%20much%20of%20the%20Earth.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Extratropical cyclones&lt;/a&gt; rely on sharp changes in temperature, which is enhanced during winter. That is, the tropics maintain the amount of radiation that they get, while the higher latitudes get less incoming radiation (0 past the Ant/arctic circle). Large change in radiation means large change in temperature which means more extratropical storms in the winter.&lt;/p&gt;&#xA;&lt;p&gt;For tropical storms, there is an acronym that I memorized for the necessary (but not sufficient) ingredients for them to develop (the technical term is &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_cyclogenesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;tropical cyclogenesis&lt;/a&gt;): &lt;strong&gt;LIVERS&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;L&lt;/strong&gt;atitude- Needs to be small, but not 0&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;I&lt;/strong&gt;nstability- there needs to be a good amount of instability for convection&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;V&lt;/strong&gt;orticity - No vorticity= no spin&lt;/li&gt;&#xA;&lt;li&gt;(thermal) &lt;strong&gt;E&lt;/strong&gt;nergy - The water needs to be warm enough to sustain a tropical cyclone&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;R&lt;/strong&gt;elative Humidity - A (typical) tropical cyclone is moist. &lt;a href=&quot;https://journals.ametsoc.org/view/journals/atsc/68/8/2011jas3639.1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;While a dry tropical cyclone is theoretically possible&lt;/a&gt;, it is not common, and the barrier for formation is much smaller for a wet tropical cyclone.&lt;/li&gt;&#xA;&lt;li&gt;(little) &lt;strong&gt;S&lt;/strong&gt;hear - An ideal tropical cyclone is symmetrical. Shear disrupts the symmetry (among other issues). That being said, &lt;a href=&quot;https://journals.ametsoc.org/view/journals/mwre/146/11/mwr-d-18-0020.1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;it might be easy to overestimate the impact that shear has on weakening an already strengthened tropical cyclone.&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;If you consider all of the climate controls for those factors, then you will have a decent grasp of the seasonality of tropical cyclones.&lt;/p&gt;&#xA;&lt;p&gt;Certainly, storms that are unique to their own locale, such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Haboob&quot; rel=&quot;nofollow noreferrer&quot;&gt;haboobs&lt;/a&gt; or the &lt;a href=&quot;https://en.wikipedia.org/wiki/Meiyu_front&quot; rel=&quot;nofollow noreferrer&quot;&gt;Meiyu front&lt;/a&gt;, have their own causes and their own seasonality. But in general, if you understand what drives the weather systems, then you can generate how they fluctuate by the season and latitude. Of course, there are exceptions, &lt;a href=&quot;https://www.usatoday.com/story/news/world/2020/02/11/baghdad-iraq-snow-winter-storm/4722838002/&quot; rel=&quot;nofollow noreferrer&quot;&gt;such as the snowfall in Baghdad&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-07-14T00:03:02.473" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="22528" PostTypeId="2" ParentId="22523" CreationDate="2021-07-14T04:23:11.603" Score="1" Body="&lt;p&gt;Yes, In he tropics where humidity is more ubiquitous moist air currents feed systems that allow for storms. In temperate climates these storms proliferate where it's warm and humid and die off in winter.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-07-14T04:23:11.603" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22529" PostTypeId="2" ParentId="22521" CreationDate="2021-07-14T04:55:47.050" Score="-3" Body="&lt;p&gt;The Urban heat island effect offset's reliable temp data. Fact is, decades of computer models predicted temperature gains that never happened.&#xA;If you want an extrapolation of overall temp in relation to CO2 outputs here ya go (Below) Vs. model predictions.&#xA;Note the Temperature curve failed to Obey the CO2 curve. It's not to say CO2 doesn't have SOME factor in temp.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/G7rPI.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G7rPI.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-07-14T04:55:47.050" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22531" PostTypeId="2" ParentId="22519" CreationDate="2021-07-14T10:52:35.840" Score="3" Body="&lt;p&gt;No, not really. In simple terms, to be soluble in water, Pb must be in contact with it. But most of Pb is stored within the Zircon lattice, where water cannot diffuse through. For example, many zircons in metamorphic and magmatic-hydrothermal settings experience supercritical fluids, but preserve their U/Pb ratios (e.g. inherited cores in metasedimentary zircons). However, metamorphic events themselves can lead to Pb loss, which you can correct with a Tera-Wasserburg approach.&lt;/p&gt;&#xA;" OwnerUserId="20625" LastActivityDate="2021-07-14T10:52:35.840" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22532" PostTypeId="1" AcceptedAnswerId="22533" CreationDate="2021-07-14T11:45:10.767" Score="3" ViewCount="293" Body="&lt;p&gt;As part of the home dashboard I am developing, I get information about incoming rain. It is given in mm/min.&lt;/p&gt;&#xA;&lt;p&gt;Is there a consensus on the precipitation rate that is called &amp;quot;&lt;em&gt;light rain&lt;/em&gt;&amp;quot;, or &amp;quot;&lt;em&gt;heavy rain&lt;/em&gt;&amp;quot;? (I would like, if this is possible, to use some standardized naming)&lt;/p&gt;&#xA;" OwnerUserId="7288" LastActivityDate="2021-12-10T16:31:35.537" Title="Is there a consensus on the &quot;heaviness&quot; of rain?" Tags="|meteorology|weather-forecasting|rainfall|rain|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22533" PostTypeId="2" ParentId="22532" CreationDate="2021-07-14T12:09:57.660" Score="4" Body="&lt;p&gt;The German Weather Service (Deutscher Wetterdienst, DWD) provides the following definitions:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Heavy rain is defined as large amounts of precipitation during a fixed period of time. [...]&lt;/p&gt;&#xA;&lt;p&gt;The DWD issues warnings of heavy rain using three categories:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;heavy rain: 15 to 25 l/m² within 1 hour or 20 to 35 l/m² within 6 hours&lt;/li&gt;&#xA;&lt;li&gt;severly heavy rain: 25 to 40 l/m² within 1 hour or 35 to 60 l/m² within 6 hour&lt;/li&gt;&#xA;&lt;li&gt;extremely heavy rain: above 40 l/m² within 1 hour or above 60 l/m² within 6 hour&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.dwd.de/DE/service/lexikon/begriffe/S/Starkregen.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.dwd.de/DE/service/lexikon/begriffe/S/Starkregen.html&lt;/a&gt; and &lt;a href=&quot;https://www.dwd.de/DE/wetter/warnungen_aktuell/kriterien/warnkriterien.html?nn=508722#doc453962bodyText3&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.dwd.de/DE/wetter/warnungen_aktuell/kriterien/warnkriterien.html?nn=508722#doc453962bodyText3&lt;/a&gt;, translation my own.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Heavy rain is distinct from constant rain by the period of time, over which the rain falls, as well as the total amount of rain per m². Still, heavy rain events may be part of constant rain periods.&lt;/p&gt;&#xA;" OwnerUserId="14194" LastActivityDate="2021-07-14T12:09:57.660" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22534" PostTypeId="1" CreationDate="2021-07-14T12:36:30.263" Score="1" ViewCount="38" Body="&lt;p&gt;In &lt;a href=&quot;https://en.wikipedia.org/wiki/Ice_core&quot; rel=&quot;nofollow noreferrer&quot;&gt;ice cores&lt;/a&gt; a lot of data are measured and analyzed and can be plotted versus depth, for example&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;age of layers&lt;/li&gt;&#xA;&lt;li&gt;thickness of layers&lt;/li&gt;&#xA;&lt;li&gt;concentration of spurious gases&lt;/li&gt;&#xA;&lt;li&gt;concentration of solids&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/%CE%9418O&quot; rel=&quot;nofollow noreferrer&quot;&gt;delta signals&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I am looking for sources where I can find - ideally at one place - the curves that give the values of these quantities versus ice core depth, e.g. like this&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Q296C.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Q296C.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Is there possibly an interactive website where I can even zoom into such curves?&lt;/p&gt;&#xA;&lt;p&gt;Finally I'd like to know, if there is one set of &amp;quot;equations&amp;quot; which give the estimated (surface?) temperatures and CO&lt;sub&gt;2&lt;/sub&gt; concentrations as well as amount of precipitation as functions of the measured data. I imagine such equations must exist – or are they too complicated to write down? (The equations should also give the error range! Side question: Does the error range decrease with time (i.e. increase with depth)?)&lt;/p&gt;&#xA;" OwnerUserId="17431" LastEditorUserId="17431" LastEditDate="2021-07-15T08:17:42.673" LastActivityDate="2021-07-15T08:17:42.673" Title="From ice core analysis to temperature curves" Tags="|paleoclimatology|climatology|data-analysis|reference-request|ice-sheets|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22536" PostTypeId="1" CreationDate="2021-07-14T20:53:20.983" Score="9" ViewCount="2381" Body="&lt;p&gt;I am teaching a secondary school course on my state's local history. The textbook begins with the history of the first humans, yet I think it is unfair not to start back much earlier, introducing the geologic history.&lt;/p&gt;&#xA;&lt;p&gt;Students finished a lesson on the slow changes that took place over the past 4.5 billion years on Earth, gradually leading to the formation of our state. I want the students to understand these changes haven't stopped, just we maybe can't see everything happening, as it happens slowly.&lt;/p&gt;&#xA;&lt;p&gt;A later lesson will focus on human changes, but I want to first cover natural changes:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Earth's magnetic pole is moving.&lt;/li&gt;&#xA;&lt;li&gt;Moon slowly getting further away.&lt;/li&gt;&#xA;&lt;li&gt;Days are slowly getting longer.&lt;/li&gt;&#xA;&lt;li&gt;Tectonic plate slowly moving 1 inch west-southwest.&lt;/li&gt;&#xA;&lt;li&gt;Wind and rain slowly shaping landscape.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Without having a geology background, I'm quite concerned I overlooked some important changes. There are some locally specific features I identified (such as a slowly-splitting rift valley), but are there any other major changes I ought to include?&lt;/p&gt;&#xA;" OwnerUserId="17645" LastEditorUserId="2470" LastEditDate="2021-07-16T05:10:37.480" LastActivityDate="2021-07-17T23:15:04.947" Title="What significant factors influencing geological change are still occurring?" Tags="|geology|earth-history|" AnswerCount="4" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="22537" PostTypeId="2" ParentId="22536" CreationDate="2021-07-14T21:53:40.567" Score="15" Body="&lt;p&gt;The effects of Earth's past climate variations on the landscape, especially &lt;a href=&quot;https://en.wikipedia.org/wiki/Ice_age&quot; rel=&quot;nofollow noreferrer&quot;&gt;glaciation&lt;/a&gt;, cannot be underestimated.&lt;/p&gt;&#xA;&lt;p&gt;The multiple glacial advances and retreats over the last 4 million years or so have been a major (and sometimes the principal) force that shaped the current landscape. We're actually living in one of the temporary glacial minima - there will be more advances and retreats in the future.&lt;/p&gt;&#xA;&lt;p&gt;Some important effects include:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;mass removal and depostion of rock material (it's why the US has good soil that used to be in Canada). Also, some sizeable landmasses such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Long_Island&quot; rel=&quot;nofollow noreferrer&quot;&gt;Long Island&lt;/a&gt; consist of &lt;a href=&quot;https://en.wikipedia.org/wiki/Moraine&quot; rel=&quot;nofollow noreferrer&quot;&gt;moraine&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;major gouges in the landscape, such as the ones that hold the Great Lakes, or &lt;a href=&quot;https://en.wikipedia.org/wiki/U-shaped_valley&quot; rel=&quot;nofollow noreferrer&quot;&gt;U-shaped valley&lt;/a&gt;s in the mountains&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Post-glacial_rebound&quot; rel=&quot;nofollow noreferrer&quot;&gt;isostatic rebound&lt;/a&gt; affecting coasts to this day&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Estuary&quot; rel=&quot;nofollow noreferrer&quot;&gt;estuaries&lt;/a&gt; (drowned river valleys) and &lt;a href=&quot;https://en.wikipedia.org/wiki/Barrier_island&quot; rel=&quot;nofollow noreferrer&quot;&gt;barrier island&lt;/a&gt;s that result from sea level drop during a glacial maximum, followed by sea level rise as they melt. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Black_Sea&quot; rel=&quot;nofollow noreferrer&quot;&gt;Black Sea&lt;/a&gt; is a drowned freshwater lake.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;ancient &lt;a href=&quot;https://en.wikipedia.org/wiki/Glacial_lake&quot; rel=&quot;nofollow noreferrer&quot;&gt;glacial lake&lt;/a&gt;s &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Agassiz&quot; rel=&quot;nofollow noreferrer&quot;&gt;created by trapped meltwater&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Pluvial_lake&quot; rel=&quot;nofollow noreferrer&quot;&gt;increased rainfall&lt;/a&gt;, leaving &lt;a href=&quot;https://en.wikipedia.org/wiki/Varve&quot; rel=&quot;nofollow noreferrer&quot;&gt;lake bottom sediment&lt;/a&gt; in the soil and fossil shorelines. Sometimes the lakes drained catastrophically, leaving weird erosional features such as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Channeled_Scablands&quot; rel=&quot;nofollow noreferrer&quot;&gt;Channeled Scablands&lt;/a&gt;. Sometimes they never drained at all (the Great Lakes).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;aeolian (&lt;a href=&quot;https://en.wikipedia.org/wiki/Loess&quot; rel=&quot;nofollow noreferrer&quot;&gt;loess&lt;/a&gt;) deposits from dessicated areas near the ice front&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;And that's just what I could think of in 5 minutes.&lt;/p&gt;&#xA;&lt;p&gt;Not only that, major glaciations in the distant past have affected the geological record, such as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Snowball_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Snowball Earth&lt;/a&gt; episodes ~ 700 Ma ago that nearly eradicated a billion years of stratigraphy.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2021-07-17T23:15:04.947" LastActivityDate="2021-07-17T23:15:04.947" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22538" PostTypeId="2" ParentId="22515" CreationDate="2021-07-15T03:28:40.210" Score="1" Body="&lt;p&gt;Water velocity increasing near bridge pylons is literally the Bernoulli principle manifested. Mass balance on either side of a constriction requires that flow speed up within the constriction itself.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, since nothing confines water at the surface, it is free to rise (and fall as shear stresses dictate), creating local waves...hence fast moving rough water in narrow channels, under bridges, around jetties, and even over sand bars.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2021-07-15T03:28:40.210" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22539" PostTypeId="2" ParentId="22536" CreationDate="2021-07-15T07:37:37.110" Score="4" Body="&lt;p&gt;You could mention the fact that the solid Earth (i.e., not the atmosphere) is slowly cooling down, as the two main sources of heat, primordial and radioactive, are slowly decaying. Because of this, the planet may become tectonically dead at some point.&lt;/p&gt;&#xA;&lt;p&gt;Gradual change over long periods of time is known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Uniformitarianism&quot; rel=&quot;nofollow noreferrer&quot;&gt;uniformitarianism&lt;/a&gt;, and has been opposed to catastrophism in the 19th century. From a history of sciences point of view, it could be worth mentioning the dispute between the two theories (and the fact that the evolution of Earth is actually driven by a bit of both).&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2021-07-15T11:53:26.970" LastActivityDate="2021-07-15T11:53:26.970" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22540" PostTypeId="1" CreationDate="2021-07-15T08:37:54.663" Score="3" ViewCount="55" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gPlg4.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gPlg4.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Why does the number of components become 3 when calculating the phase rule of rocks consisting of MS and Chl.&lt;/p&gt;&#xA;&lt;p&gt;According to the &lt;em&gt;Goldschmidt's minimal phase&lt;/em&gt; rule, in most cases, the degree of freedom of rock in the field is 2.&lt;/p&gt;&#xA;&lt;p&gt;The component is the minimum number of components that allow the compositional mineral to form.&lt;/p&gt;&#xA;&lt;p&gt;What is the number of components of the rock? 2 or 3?&lt;/p&gt;&#xA;" OwnerUserId="22990" LastEditorUserId="22648" LastEditDate="2021-07-22T08:54:04.247" LastActivityDate="2021-07-22T08:54:04.247" Title="Phase rule for akf triangle diagram in the field of metamorphic rock lithography" Tags="|metamorphism|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22542" PostTypeId="1" CreationDate="2021-07-15T23:31:28.307" Score="5" ViewCount="126" Body="&lt;p&gt;The sites of ancient Mesopotamian civilizations tend to be very dry, unlike those of ancient Egypt. Looking at the areas via online maps also shows, that while the Nile river basin remains very green, the areas around the Tigris and Euphrates look pretty dry (admittedly this might not be the best metric).&lt;/p&gt;&#xA;&lt;p&gt;I tried to find more information on this, and while it seems that government programs in the last century contributed to desertification in Iraq, clearly the phenomenon is considerably older. Another statement I have seen repeated is that desertification occurred on account of soil salination “due to millennia of agricultural exploitation”. Admittedly Mesopotamia has seen large-scale agriculture before Egypt — but in total seems to have remained suited for agriculture for a shorter time.&lt;/p&gt;&#xA;&lt;p&gt;What's the difference then?&lt;/p&gt;&#xA;" OwnerUserId="22995" LastEditorUserId="22995" LastEditDate="2021-07-19T01:06:22.493" LastActivityDate="2021-07-19T17:28:39.223" Title="Why did the Tigris and Euphrates but not the Nile river basins experience desertification?" Tags="|earth-history|agriculture|desertification|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22543" PostTypeId="2" ParentId="22536" CreationDate="2021-07-16T05:29:09.487" Score="1" Body="&lt;p&gt;Major geologic changes occur during natural events.  Events like wildfire, floods, earthquakes, drought, volcanic eruptions, tsunamis, etc. can severely alter the landscape and allow new geologic processes to take place.  For instance, after a landscape is hit by wildfire, it is easily subject to flash flooding and you get soil loss.  This was not really &amp;quot;slow&amp;quot; on a geologic time scale, it was circumstantial.&lt;/p&gt;&#xA;&lt;p&gt;This biggest event of all is a meteor impact, which can cause tsunamis, fires, etc. and also introduce new material to Earth.&lt;/p&gt;&#xA;&lt;p&gt;Perhaps overlooked on your list is the affect that life has on geology:&#xA;from microorganisms and worms in the soil creating humus to &lt;a href=&quot;https://www.tandfonline.com/doi/abs/10.1080/15230430.1999.12003328#:%7E:text=Animals%20can%20exert%20a%20very,sediment%20transport%20in%20the%20alpine.&amp;amp;text=Animals%20exert%20a%20direct%20influence,needle%20ice%2C%20and%20wind%20erosion.&quot; rel=&quot;nofollow noreferrer&quot;&gt;larger animals&lt;/a&gt; that burrow and dig, to vegetation that can transform local soil, moisture, and temperature... plants and animals do make a difference.&lt;/p&gt;&#xA;&lt;p&gt;Finally, I know you said you will talk about people's influence later, but make sure they know we are in a new geologic epoch, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Anthropocene&quot; rel=&quot;nofollow noreferrer&quot;&gt;anthropocene&lt;/a&gt;.  And, while human influence on climate is very important, we are possibly causing a bigger geologic effect with plastic waste.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2021-07-16T05:29:09.487" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22544" PostTypeId="1" AcceptedAnswerId="23028" CreationDate="2021-07-16T11:15:27.987" Score="4" ViewCount="184" Body="&lt;p&gt;I'm working on a script for calculating the Rainfall Anomaly Index&lt;sup&gt;1&lt;/sup&gt; (RAI) for an area using satellite imagery to estimate precipitation. The context I have seen the RAI used in before is for weather station estimates, which essentially corresponds to a single pixel in my imagery. What I would like to do is calculate droughts using the imagery, but the RAI formula changes depending on if the difference in rainfall in the given time period is negative (drought) or positive (flood).&lt;/p&gt;&#xA;&lt;p&gt;So my scenario is that within the area I would like to calculate the RAI for I have some pixels that experience a drought, and some that technically experience flooding. My ideas to deal with this is to a) take an average for the entire area and based on that either use the positive or the negative formula or b) calculate the index for each pixel individually, then averaging the index at the end.&lt;/p&gt;&#xA;&lt;p&gt;Any suggestions as to how I should approach this problem?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt;The definition of RAI that I'm using is this from &lt;a href=&quot;https://www.semanticscholar.org/paper/Space-Time-Distribution-of-Rainfall-Anomaly-Index-Costa-Rodrigues/9ade87dfe6b27ab7afd33398303627cf7461e171&quot; rel=&quot;nofollow noreferrer&quot;&gt;Space-Time Distribution of Rainfall Anomaly Index (RAI) for the Salgado Basin, Ceará State - Brazil&lt;/a&gt; , which in turn cites&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;ROOY MP. van. A Rainfall Anomaly Index Independent of Time and Space. Notos. 1965; 14, 43p.&lt;/li&gt;&#xA;&lt;li&gt;FREITAS MAS. Um sistema de suporte à decisão para o monitoramento de secas meteorológicas em regiões semiáridas. Rev. Tecnol. 2005; (suppl 19): p. 84-95.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;For the time being I've decided to use a fairly simple index that only considers precipitation as an input to get my code to work.&lt;/p&gt;&#xA;" OwnerUserId="22631" LastEditorUserId="6031" LastEditDate="2021-07-21T00:34:32.197" LastActivityDate="2021-10-22T15:46:20.950" Title="Rainfall Anomaly Index using satellite data" Tags="|hydrology|precipitation|weather-satellites|gis|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22547" PostTypeId="2" ParentId="22536" CreationDate="2021-07-16T20:08:49.490" Score="1" Body="&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Carbon cycling through the mantle&lt;/strong&gt; is a hugely important geologic process. Carbon gets into the mantle when subducted continental arc materials bearing rich, organic runoff are carried to depth, then exuded through volcanism at plate boundaries. That rich organic runoff is created by rain which is deeply influenced by...&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Oceanic currents&lt;/strong&gt; which largely control planet-wide weather. These currents are influenced by plate tectonics, Milankovich Cycles, as well as global temperature.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Technically, #2 is an &amp;quot;oceanographic&amp;quot; process, but it's influence on crustal geologic processes is profound. Processes like the flipping of the poles, the distancing moon, wind erosion are interesting but play little part influencing the bigger geological picture.&lt;/p&gt;&#xA;&lt;p&gt;Your later lesson might include how human-caused global warming is affecting global ocean currents and disturbing stable processes reflected in the geochemistry at plate boundaries. You might tell your kids how 25 million years from now, a terrestrial-squid geology grad student may study the relationship between the sudden disappearance of carbon-rich andesites from the western South American plate and the anthropocene.&lt;/p&gt;&#xA;&lt;p&gt;Incidentally, if you'd like to show your students some riveting &amp;quot;future-geology&amp;quot;, I highly recommend the series &amp;quot;&lt;a href=&quot;https://www.thefutureiswild.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Future is Wild&lt;/a&gt;&amp;quot;, in which global geology (and evolution) is observed 5, 100, and 200 million years into the future.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2021-07-16T20:08:49.490" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22548" PostTypeId="1" AcceptedAnswerId="22575" CreationDate="2021-07-16T23:06:40.700" Score="1" ViewCount="107" Body="&lt;p&gt;I would like to compare NOAA GFS (Global Forecast System) geopotential height from ASL and GTOPO30.&lt;/p&gt;&#xA;&lt;p&gt;However, I cannot find vertical offset information in GFS geopotential height. Does anyone know where it is located?&lt;br /&gt;&#xA;(And, I assume that GTOPO30 is in the geometric height from ASL ... is that correct?)&lt;/p&gt;&#xA;" OwnerUserId="23001" LastActivityDate="2021-07-21T03:25:17.757" Title="What is the vertical offset of geopotential height from ellipsoidal height in GFS?" Tags="|gfs|coordinate-system|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22549" PostTypeId="1" CreationDate="2021-07-17T00:37:55.097" Score="7" ViewCount="190" Body="&lt;p&gt;In &lt;em&gt;Feynman Lectures on Physics Volume I&lt;/em&gt;, Feynman talks about the relation between Physics and Geology. He says “Mountains are no lower today, on the average, than they were in the past”.&lt;/p&gt;&#xA;&lt;p&gt;Through what methodology do we know what the past heights of mountains were?&lt;/p&gt;&#xA;" OwnerUserId="22037" LastActivityDate="2023-05-25T12:00:30.097" Title="How can we know the past height of mountains?" Tags="|geology|mountains|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22550" PostTypeId="2" ParentId="22468" CreationDate="2021-07-17T06:11:47.557" Score="3" Body="&lt;p&gt;What you are suggesting is possible in theory but futile for any practical purposes.  The concentrations of pollutants varies vertically throughout the atmosphere, so calculating a single value that represents the average concentration in the vertical slab is inherently flawed.  Attempting to pick a vertical height that just represents the boundary layer will also not work, since the satellite retrieval is sensitive to the free troposphere, not the surface. You also have the &amp;quot;below cloud&amp;quot; portion of the vertical column to deal with sometimes, which is completely based on model data.  If the TROPOMI VCD products could be easily converted to surface concentrations, they would've done it already and provided it as a product.&lt;/p&gt;&#xA;&lt;p&gt;As &lt;a href=&quot;https://so2.gsfc.nasa.gov/no2/FAQs.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA says&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Can satellites measure &amp;quot;nose-level&amp;quot; concentrations?&#xA;The short answer is &amp;quot;no&amp;quot; because the majority of satellite instruments that measure pollutants of interest to the AQ community are downward-looking, providing limited information on the vertical structure of the pollutant in the atmosphere. Satellite instruments that measure ozone, NO2, formaldehyde, and SO2 detect the number of molecules between the instrument and the Earth's surface (i.e., a Vertical Column Density or VCD).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You may be able to find SO2 and CO layers with some mixing ratio &amp;quot;profiles&amp;quot;, but it's really poor when compared to surface measurements.   However, you can integrate sonde measurements to get something comparable to a VCD, if you use the &lt;a href=&quot;https://sentinel.esa.int/documents/247904/2474726/Sentinel-5P-Level-2-Product-User-Manual-Nitrogen-Dioxide&quot; rel=&quot;nofollow noreferrer&quot;&gt;averaging kernels&lt;/a&gt;.  You can also calculate a modeled VCD (e.g. from CMAQ or other CTM) using the TROPOMI averaging kernels, which is then comparable to the satellite retrieval.&lt;/p&gt;&#xA;&lt;p&gt;The vertical concentration profile assumption is part of the algorithm that goes into the column retrieval.  So, any attempt to derive surface concentration from the VCD is inherently based on model data and is not sensitive to the actual surface concentrations.&lt;/p&gt;&#xA;&lt;p&gt;To complicate matters, your surface measurements will vary in time due to local sources (think neighborhood airshed), meteorology, and photochemistry.  Your VCD retrievals will be for one timestep per day over a large multi-km area which will vary depending on surface albedo, cloud cover, season, and which pixel on the detector was used, how old the detector is, etc. ... even if the column itself remained the same.  Another factor is sensitivity to a clean atmosphere, because if the atmosphere is not heavily polluted, the radiance signal will not be strong and you will basically be looking at noise.&lt;/p&gt;&#xA;&lt;p&gt;Take a look at these peer reviewed papers, where they compare to surface measurements but do not attempt to convert VCD to surface concentrations:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.researchgate.net/publication/346221881_Nitrogen_Dioxide_NO2_Pollution_Monitoring_with_Sentinel-5P_Satellite_Imagery_over_Europe_during_the_Coronavirus_Pandemic_Outbreak&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nitrogen Dioxide (NO2) Pollution Monitoring with Sentinel-5P Satellite Imagery over Europe during the Coronavirus Pandemic Outbreak&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://amt.copernicus.org/articles/13/205/2020/amt-13-205-2020.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Comparison of TROPOMI/Sentinel-5 Precursor NO2 observations&#xA;with ground-based measurements in Helsinki&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;And you can see this tangentially related post:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://atmosphere.copernicus.eu/flawed-estimates-effects-lockdown-measures-air-quality-derived-satellite-observations?q=flawed-estimates-effects-lockdown-measures-air-quality-satellite-observations&quot; rel=&quot;nofollow noreferrer&quot;&gt;Flawed estimates of the effects of lockdown measures on air quality derived from satellite observations&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;And if you really want to go down the rabbit hole, you can see this effort to use machine learning to estimate surface NO2 from TropOMI:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://elib.dlr.de/141411/1/remotesensing-13-00969-v2.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Estimation of Surface NO2 Concentrations over Germany from TROPOMI Satellite Observations Using a Machine Learning Method&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2021-07-18T04:41:28.033" LastActivityDate="2021-07-18T04:41:28.033" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22552" PostTypeId="1" CreationDate="2021-07-17T13:53:37.447" Score="3" ViewCount="452" Body="&lt;p&gt;&lt;strong&gt;If a popular website provides an hourly forecast, and it states at 12:00pm there will be a 20% chance of precipitation and 2.5 mm of rain...&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;What does the &amp;quot;2.5 mm of rain&amp;quot; mean?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;(A)&lt;/strong&gt; ... If it does rain, on average there will be 2.5 mm of rain.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;(   20% * 2.5mm   +   80% * 0.0mm   ) = 0.5 mm average rainfall &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;&lt;strong&gt;(B)&lt;/strong&gt; ... &amp;quot;2.5 mm of rain&amp;quot; is a &amp;quot;statistical prediction&amp;quot; which means that a huge storm could be coming and that if it does rain there will be about ~12.5 mm of rain for the hour but if the storm misses then there will be 0.0 mm of rain.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;(   20% * 12.5mm   +   80% * 0.0mm   ) = 2.5 mm average rainfall&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;&lt;strong&gt;How should a person interpret a weather forecast of 2.5 mm with a 20% probability? There is a big difference between potentially 2.5 mm of rain and 12.5 mm of heavy rain.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;In (A)&lt;/strong&gt;, a typical person reading may imagine how deep 2.5 mm is and not be worried as that is just a thin film of water. However if a site reported 12.5 mm, they may imagine puddles and hence be worried. Since a typical person is not mathematically inclined and unlikely to be knowledgeable in conditional probabilities, using (A) is potentially more useful for most people.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;In (B)&lt;/strong&gt;, a typical person reading imagines how deep 2.5 mm is and is not worried. That person will be very surprised if the storm hits. A statistical prediction is useful for science/math people and keeps the prediction independent of the PoP %. It is however very misleading for 95-99% of people that happen to be not versed in meteorology. I assume (B) is used but wanted to confirm.&lt;/p&gt;&#xA;" OwnerUserId="23005" LastEditorUserId="23005" LastEditDate="2021-07-18T03:11:18.577" LastActivityDate="2021-07-18T03:11:18.577" Title="Relationship between Probability of Precipitation and Predicted Amount of Rain" Tags="|precipitation|rainfall|rain|" AnswerCount="1" CommentCount="9" ClosedDate="2021-07-18T03:25:56.557" ContentLicense="CC BY-SA 4.0" />
  <row Id="22553" PostTypeId="2" ParentId="22552" CreationDate="2021-07-17T22:50:58.573" Score="1" Body="&lt;p&gt;A popular website (let us not give any names) may have a&#xA;a) computer generated forecast.&#xA;b) computer generated forecast interpreted by a man (meteorologist specialized in short-term or long-term forecasts).&#xA;In either case, &amp;quot;20% chance of rain&amp;quot; for a particular location is simply the full rain probability for a &amp;quot;prognosis area&amp;quot; times a probability to affect x% of the full prognosis area.&lt;/p&gt;&#xA;&lt;p&gt;From a document downloaded from weather.gov&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This point probability of precipitation is predetermined and arrived at by the forecaster by&#xA;multiplying two factors:&#xA;Forecaster certainty that precipitation will form or move into the area&#xA;X&#xA;Areal coverage of precipitation that is expected&#xA;(and then moving the decimal point two places to the left)&#xA;Using this, here are two examples giving the same statistical result:&#xA;(1) If the forecaster was 80% certain that rain would develop but only expected to cover 50% of&#xA;the forecast area, then the forecast would read &amp;quot;a 40% chance of rain&amp;quot; for any given location.&#xA;(2) If the forecaster expected a widespread area of precipitation with 100% coverage to&#xA;approach, but he/she was only 40% certain that it would reach the forecast area, this would, as&#xA;well, result in a &amp;quot;40% chance of rain&amp;quot; at any given location in the forecast area.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Moving to mm-s or in-s. The computer software predicts precipitation rates according to input parameters. 2,5 mm occuring in 2hrs time in Columbus OH means that the software used (GFS, for example) probed initial conditions of current/now wether from Columbus and vecinity of, let us say, 100 miles/160 kms and found that if rain clouds form directly above Columbus, or existing rain clouds in vecinity reach Columbus, 2,5 mm is the most likely pp quantity to be measured at a weather station's rain gauge.&lt;/p&gt;&#xA;" OwnerUserId="17033" LastActivityDate="2021-07-17T22:50:58.573" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22554" PostTypeId="2" ParentId="22532" CreationDate="2021-07-17T23:16:54.557" Score="6" Body="&lt;p&gt;If there was a worldwide standard, then WMO would have imposed it to its members. Here are the definitions in the American (NOAA/NWS) standard&lt;/p&gt;&#xA;&lt;p&gt;(&lt;a href=&quot;http://www.njweatherscan.com/definitions_of_precipitation.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;summarized at NJWeatherScan&lt;/a&gt;, initially from manuals like &lt;a href=&quot;https://www.faa.gov/documentLibrary/media/Order/Order_JO_7900.5E.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one (PDF page 66, page label 58)&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;Light rain: falling rate of less than 2.54 mm/h.  This would be &amp;lt; 0.042 mm/min.&lt;/p&gt;&#xA;&lt;p&gt;Moderate rain: falling rate of more than 2.8 mm/h, but less than 7.6 mm/h.  This would be 0.042 mm/min - 0.127 mm/min.&lt;/p&gt;&#xA;&lt;p&gt;Heavy rain: falling rate of more than 7.6 mm/h. This would be &amp;gt; 0.127 mm/min.&lt;/p&gt;&#xA;&lt;p&gt;So clearly different standards &lt;a href=&quot;https://earthscience.stackexchange.com/a/22533/6298&quot;&gt;compared to the DWD answer&lt;/a&gt; (note: 1 l/m² is equivalent to 1mm). Nowadays, automated weather stations use rain gauges with sensors, so a modern station with the computer inside has a clear and accurate computation of rain/snow falling rates. But there is no universal standards.&lt;/p&gt;&#xA;" OwnerUserId="17033" LastEditorUserId="6467" LastEditDate="2021-12-10T16:31:35.537" LastActivityDate="2021-12-10T16:31:35.537" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22555" PostTypeId="1" CreationDate="2021-07-18T02:49:59.297" Score="17" ViewCount="5386" Body="&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/22532/6031&quot;&gt;Is there a consensus on the &amp;quot;heaviness&amp;quot; of rain?&lt;/a&gt; and &lt;a href=&quot;https://earthscience.stackexchange.com/q/22552/6031&quot;&gt;Relationship between Probability of Precipitation and Predicted Amount of Rain&lt;/a&gt; remind me of a gedankenexperiment of mine. I like to imagine a home project Arduino or Raspberry Pi-based weather monitor that lets me know the precipitation situation outside.&lt;/p&gt;&#xA;&lt;p&gt;The &amp;quot;state of the art&amp;quot; for electronic hobbyists is the interdigitated electrode sensor, which is the way it is because it's easy to mass produce cheaply as a printed circuit board, not because it's a good idea.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/G49do.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G49do.gif&quot; alt=&quot;lame puddle detector&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: Last Minute Engineers' &lt;a href=&quot;https://lastminuteengineers.com/rain-sensor-arduino-tutorial/&quot; rel=&quot;noreferrer&quot;&gt;How Rain Sensor Works and Interface it with Arduino&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This resistance is inversely proportional to the amount of water:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The more water on the surface means better conductivity and will result in a lower resistance.&lt;/li&gt;&#xA;&lt;li&gt;The less water on the surface means poor conductivity and will result in a higher resistance.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The sensor produces an output voltage according to the resistance, which by measuring we can determine whether it’s raining or not.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Earth scientists, amateur and professionals alike will tear out their hair since 1) a puddle may tell you if it has rained, &lt;em&gt;but not if it's raining&lt;/em&gt; and 2) conductivity of rainwater varies dramatically, so conductivity is will not correlate directly to amount or area covered.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What are ways to make a &amp;quot;How hard is it raining?&amp;quot; detector for personal use?&lt;/p&gt;&#xA;&lt;p&gt;I'm thinking of a laser pointers, photodiodes, rainproofed PiCamera modules, microphones, level sensors, but the sky's the limit. What needs to be addressed is how &amp;quot;rained on&amp;quot; I'm going to feel when I go outside, and a static puddle detector is not going to do that very well.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2021-07-19T10:13:50.023" LastActivityDate="2021-07-30T09:51:45.997" Title="Ways to make a &quot;How hard is it raining?&quot; detector for personal use?" Tags="|meteorology|rainfall|rain|instrumentation|environmental-sensors|" AnswerCount="8" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="22556" PostTypeId="2" ParentId="22555" CreationDate="2021-07-18T03:42:44.047" Score="13" Body="&lt;p&gt;One way to do that is to estimate how much water is changing. If you can ignore the spill over, then that is approximately how much the puddle is changing.&lt;/p&gt;&#xA;&lt;p&gt;Another idea you can use is to measure the changing weight of a rain gauge (that will need to be emptied daily, unless you can rig something that will do that for you). The faster the weight increases, the heavier it is raining. Even though it may cause a measurement problem, I would say a wider gauge will accumulate more weight, and you would just have to do some math with the density of water and the translation to a standard rain gauge for proper display.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-07-18T03:42:44.047" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="22557" PostTypeId="2" ParentId="22555" CreationDate="2021-07-18T06:03:51.183" Score="14" Body="&lt;p&gt;Upon reading the question my first thought was, please define what is meant by &amp;quot;how hard is it raining?&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;My initial tangent thought was &amp;quot;what about the impact energy of the rain&amp;quot; - heavy rain can be felt. Anyone who has heard rain fall on a metal or poly-carbonate roof will know the difference in noise produced by light and heavy rain.&lt;/p&gt;&#xA;&lt;p&gt;The impact energy of rain will be determined by the size of the rain drops, their length of fall and the density of rain drops for a given area. Some researchers have &lt;a href=&quot;https://www.paperpublications.org/upload/book/Harnessing%20of%20Kinetic%20Energy%20of%20Raindrops-380.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;investigated&lt;/a&gt; the potential to &lt;a href=&quot;https://phys.org/news/2008-01-power-harvesting-energy-sky.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;harvest the kinetic energy of rain&lt;/a&gt;. Other's have even investigated the &lt;a href=&quot;https://journals.plos.org/plosone/article?id=10.1371/journal.pone.0158472&quot; rel=&quot;nofollow noreferrer&quot;&gt;sound pressure produced by rain drops&lt;/a&gt; and its potential effect on soil erosion.&lt;/p&gt;&#xA;&lt;p&gt;Back to your proposed electronic rain intensity device. I think the &amp;quot;resistance plate&amp;quot; type of sensor might be using the wrong type of sensor. One of the problems I see with such a sensor is once it is totally or mostly inundated with water how does one determine rainfall intensity when additional raindrops don't affect the inundation level and hence the electrical resistance produced by the sensor?&lt;/p&gt;&#xA;&lt;p&gt;A digital accelerometer or pressure sensor connected to a system that can record the impact pressure and the time of impact would be a better system.&lt;/p&gt;&#xA;&lt;p&gt;A simple analog device would be placing a microphone to the underside of a piece of sheet metal and connecting the output from the microphone to a sound meter - the louder the sound, the heavier the rain.&lt;/p&gt;&#xA;&lt;p&gt;Using a horizontal laser beam with a light receptor or a doorway beam, as used in shops or restaurants, etc., could also be used where the rain intensity would interfere with the amount of light received by the light sensor. One of the situations where such a device would not work would be during fog.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-07-30T09:51:45.997" LastActivityDate="2021-07-30T09:51:45.997" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22558" PostTypeId="1" AcceptedAnswerId="22579" CreationDate="2021-07-18T11:35:50.283" Score="2" ViewCount="45" Body="&lt;p&gt;I want to validate a model and compare several parameterizations. I have some observations so I calculated the RMSE for each parameterization  with the best meteorological forcing.&#xA;However I want to nuance with the variability of the forcing. I suppose that more the forcing has an impact on outputs in its range of uncertainties, less the parameterization  explains the amelioration of the RMSE.&lt;/p&gt;&#xA;&lt;p&gt;In my case, I have 5 forcing files and 2 different parameterizations, the output &lt;span class=&quot;math-container&quot;&gt;$Y$&lt;/span&gt; is a time series. I name &lt;span class=&quot;math-container&quot;&gt;$Y_{ij}(t)$&lt;/span&gt; each output with the forcing &lt;span class=&quot;math-container&quot;&gt;$i$&lt;/span&gt; and the param &lt;span class=&quot;math-container&quot;&gt;$j$&lt;/span&gt;&#xA;and I name the mean of &lt;span class=&quot;math-container&quot;&gt;$Y_{ij}(t)$&lt;/span&gt; for each time step between all the forcing with the parameterization j as &lt;span class=&quot;math-container&quot;&gt;$\bar{Y_j}(t)$&lt;/span&gt; and the time series of the observation is &lt;span class=&quot;math-container&quot;&gt;$y(t)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;I want to compare the RMSE with the following formulae (where I replace &lt;span class=&quot;math-container&quot;&gt;$y(t)$&lt;/span&gt; by &lt;span class=&quot;math-container&quot;&gt;$\bar{Y_j}(t)$&lt;/span&gt;):&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{1}{N_t} \sum_k (Y_{ij}(t_k)-\bar{Y_j}(t_k))^2$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Finally, I want to conclude that if the ratio  &lt;span class=&quot;math-container&quot;&gt;$ \frac{RMSE}{\sqrt{\frac{1}{N_t} \sum_k (Y_{ij}(t_k)-\bar{Y_j}(t_k))^2}} $&lt;/span&gt; is near to 1 so it is difficult to conclude because the error on the forcing lead to the most of the sensitivity on the outputs and if it is near to 0, the parameterization  really improves the model to fit to the observations.&lt;/p&gt;&#xA;&lt;p&gt;Is this approach relevant?&lt;/p&gt;&#xA;" OwnerUserId="22090" LastEditorUserId="22090" LastEditDate="2021-07-22T08:46:31.260" LastActivityDate="2021-07-22T08:46:31.260" Title="Pertinence for a formulae similar of the RMSE to measure the meteorologic forcing impact on the variability on a model output" Tags="|land-surface-models|validation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22559" PostTypeId="2" ParentId="22555" CreationDate="2021-07-18T14:25:28.667" Score="17" Body="&lt;p&gt;If you're open to a more mechanical solution, I'd suggest building a &amp;quot;tipping bucket rain gauge&amp;quot;, best explained by a picture (source: &lt;a href=&quot;https://www.researchgate.net/figure/Sideview-of-tipping-bucket-Rain-Gauge_fig4_304297354&quot; rel=&quot;noreferrer&quot;&gt;https://www.researchgate.net/figure/Sideview-of-tipping-bucket-Rain-Gauge_fig4_304297354&lt;/a&gt;):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.researchgate.net/profile/Harreez-Villaruz/publication/304297354/figure/fig4/AS:436146888024067@1480996929475/Sideview-of-tipping-bucket-Rain-Gauge.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://www.researchgate.net/profile/Harreez-Villaruz/publication/304297354/figure/fig4/AS:436146888024067@1480996929475/Sideview-of-tipping-bucket-Rain-Gauge.png&quot; alt=&quot;Tipping bucket rain gauge&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This should be relatively easy to build and it's trivial to read this electronically by detecting the time it takes to tip. It seems like this is also the way that &amp;quot;real&amp;quot; weather stations measure rainfall. This is what a professional unit of this kind looks like: &lt;a href=&quot;https://www.hyquestsolutions.de/products/hardware/meteorology/model-tb3-tipping-bucket-rain-gauge-1-1-1-1-1-1-1-1-1-1-1-1-1&quot; rel=&quot;noreferrer&quot;&gt;https://www.hyquestsolutions.de/products/hardware/meteorology/model-tb3-tipping-bucket-rain-gauge-1-1-1-1-1-1-1-1-1-1-1-1-1&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="23016" LastActivityDate="2021-07-18T14:25:28.667" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="22560" PostTypeId="2" ParentId="22555" CreationDate="2021-07-18T19:17:36.450" Score="6" Body="&lt;p&gt;I would approach this by counting pings on a plate with an attached piezo or microphone. The amplitude of the ping will give the volume of the drop and the number of pings the drop quantity. This is a more robust real-world interface than an electrode sensor.&lt;/p&gt;&#xA;" OwnerUserId="23018" LastActivityDate="2021-07-18T19:17:36.450" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="22561" PostTypeId="1" AcceptedAnswerId="22569" CreationDate="2021-07-18T19:49:08.053" Score="3" ViewCount="53" Body="&lt;p&gt;The Aral Sea region has a problem with salinization of soils and drinking water, e.g. water coming from wells. As I understand it, it's caused by unsustainable cotton farming, but what is the exact mechanism? &lt;a href=&quot;https://ejfoundation.org/resources/downloads/EJF_Aral_report_cotton_net_ok.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;This&lt;/a&gt; publication says something about over-irrigation of soils and liberation of salts locked beneath soil surface, but because of the way the sentence is phrased (&amp;quot;The result is...&amp;quot;), I'm not sure it's what triggered it initially.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The result is that over-irrigated soils have accumulated excessive amounts of water capable of liberating salt locked deep beneath the soil surface.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="22632" LastActivityDate="2021-07-19T14:12:00.147" Title="How exactly is cotton production linked to salinization of potable water?" Tags="|agriculture|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22563" PostTypeId="2" ParentId="22555" CreationDate="2021-07-18T23:13:51.160" Score="13" Body="&lt;p&gt;It's not perfect, but a simple solution to the issue of a puddle building up on the resistance plate is to tilt the plate a bit, so that instead of the water building up on the plate it runs off. Your device would then look for sudden drops in resistance, indicating that a droplet has formed on the device, followed by the resistance rising again after the drop has rolled off of the plate&lt;/p&gt;&#xA;" OwnerUserId="23020" LastActivityDate="2021-07-18T23:13:51.160" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22565" PostTypeId="2" ParentId="22555" CreationDate="2021-07-19T08:38:07.347" Score="4" Body="&lt;p&gt;I sort of accidentally did this in one of my projects in a complicated, backhanded sort of way.&lt;/p&gt;&#xA;&lt;p&gt;I installed 16 soil moisture sensors in my yard as part of an attempt to track the distribution of water in the soil of a flower garden.&lt;/p&gt;&#xA;&lt;p&gt;The sensors are battery powered. They transmit their data via Bluetooth Low Energy to a couple of WiFi enabled control nodes in the yard. From the control nodes, the data are collected in a database on a Raspberry Pi.  Besides the standard data from the sensors (soil moisture, temperature, illumination, conductivity of the soil, and battery state of the sensor,) the control nodes also report how many attempts they had to make when reading the data from each sensor.&lt;/p&gt;&#xA;&lt;p&gt;I used the &amp;quot;read attempts&amp;quot; data to assign sensors to control nodes so as to reduce the read tries.  This makes the data collection more reliable and also reduces the power drawn from the CR2032 coin cells in the sensors.&lt;/p&gt;&#xA;&lt;p&gt;What I found on reviewing the data from a couple of months was that the read attempts would rise before the soil moisture readings when it started raining.&lt;/p&gt;&#xA;&lt;p&gt;The rain attenuates the Bluetooth signal enough to corrupt the data packages.  It can take several attempts to read a sensor while it is raining, even though the same sensor will be read flawlessly on the first try every time when it is not raining.&lt;/p&gt;&#xA;&lt;p&gt;I could add more sensors placed further from the control nodes, then shorten the poll time from once an hour to every few minutes.  With a little data processing, I could have an online &amp;quot;rainfall&amp;quot; page telling me how hard it is raining - or I could look out the window before I go outside.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;This is what a typical &amp;quot;rainy day&amp;quot; looks like:&lt;/p&gt;&#xA;&lt;p&gt;Not raining:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IanfX.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IanfX.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The soil moisture distribution is shown in the upper section.  The lower section shows the read try count.  Black is the normal &amp;quot;read on the first try&amp;quot; color.&lt;/p&gt;&#xA;&lt;p&gt;Rain has just started:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3pcUx.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3pcUx.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The read count has gone up on nearly all the sensors, but there hasn't been enough rain to make a difference in the soil moisture.&lt;/p&gt;&#xA;&lt;p&gt;Raining harder:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hIc9y.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hIc9y.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The soil moisture has gone up, and the read tries have gone up even more, indicating hard(er) rain.&lt;/p&gt;&#xA;&lt;p&gt;Rain has stopped:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gPviK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gPviK.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The soil moisture has gone up quite a bit compared to before the rain started.  The read tries count has dropped back down to one for all sensors.&lt;/p&gt;&#xA;&lt;p&gt;This kind of setup would be massive over kill just to tell if it is raining, but it is a nifty side effect of the setup if you already have it in place for other reasons.&lt;/p&gt;&#xA;&lt;p&gt;I could use the received signal strength indication (RSSI) value, but I didn't write that function into the control node software.  The Bluetooth library can probably supply the data, I just don't have the control nodes programmed to do it.  Maybe I ought to change it...&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;As an alternative, you could use a WiFi sniffer to collect data about WiFi base stations around your house or appartment.  I know from experience with my own phone that I can detect fewer of my neighbors' WiFi base stations on rainy days.&lt;/p&gt;&#xA;&lt;p&gt;The data normally includes a received signal strength indication (RSSI.)  Lower (more negative) numbers means a weaker signal.&lt;/p&gt;&#xA;&lt;p&gt;Track the data for all the WiFi base stations your sniffer can receive then apply some data processing and maybe some machine learning, and you could get a &amp;quot;how hard is it raining&amp;quot; indicator without installing any hardware outside your house.&lt;/p&gt;&#xA;" OwnerUserId="23023" LastEditorUserId="23023" LastEditDate="2021-07-19T08:47:10.740" LastActivityDate="2021-07-19T08:47:10.740" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="22568" PostTypeId="1" CreationDate="2021-07-19T11:13:56.907" Score="13" ViewCount="1563" Body="&lt;p&gt;The Forrest Mims YouTube video &lt;a href=&quot;https://www.youtube.com/watch?v=5besA3kwJ60&quot; rel=&quot;noreferrer&quot;&gt;An Exquisitely Rare Pollen Corona&lt;/a&gt; shows a pair of rings closely circled around the Sun with rainbow colors; blue on the inside.&lt;/p&gt;&#xA;&lt;p&gt;The first &lt;em&gt;annulus&lt;/em&gt; is easy to see, the second is faint so I've played with the color and contrast to bring out the red part to contrast with the blue sky.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What is an &amp;quot;exquisitely rare pollen corona&amp;quot;? How can pollen produce several tight rainbow circles around the Sun, and &lt;em&gt;why pollen specifically?&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yRO6r.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yRO6rm.jpg&quot; alt=&quot;Annotated screen shot from the Forrest Mims YouTube video An Exquisitely Rare Pollen Corona https://www.youtube.com/watch?v=5besA3kwJ60&quot; /&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/R7CkN.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/R7CkNm.jpg&quot; alt=&quot;Screen shot from the Forrest Mims YouTube video An Exquisitely Rare Pollen Corona https://www.youtube.com/watch?v=5besA3kwJ60&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2021-07-19T11:45:35.437" LastActivityDate="2021-07-19T22:04:00.117" Title="What is an &quot;exquisitely rare pollen corona&quot;? How can pollen produce several tight rainbow circles around the Sun, and why pollen specifically?" Tags="|atmospheric-optics|particulates|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22569" PostTypeId="2" ParentId="22561" CreationDate="2021-07-19T14:12:00.147" Score="1" Body="&lt;p&gt;the soil already contains salts, dry soils are especially prone to this as there is not enough water movement to move salts away. there are several ways the salt can get there, from slowly accumulating due to precipitation or from direct weathering of the minerals in or around the soil.  leeching just drives it deep. Irrigation then remobilizes this salt bringing it to the surface, instead of staying in the deeper parts of soil. remember irrigation adds orders of magnitude more water to dry soils then they had before, completely changing how the soil behaves.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MVzAn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MVzAn.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.researchgate.net/figure/Hydrological-processes-and-salinity-development-commonly-found-in-cropping-systems-in_fig3_228776735&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/figure/Hydrological-processes-and-salinity-development-commonly-found-in-cropping-systems-in_fig3_228776735&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2021-07-19T14:12:00.147" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22570" PostTypeId="2" ParentId="22568" CreationDate="2021-07-19T19:49:23.703" Score="18" Body="&lt;p&gt;This is an interesting phenomenon that I haven't seen before. To start off with a discussion of coronas in general, they are fundamentally caused by diffraction, a form of optical scattering where the path of light from the sun is &amp;quot;bent&amp;quot; as it passes by the edge of a small particle. A simple illustration is case D in this example figure showing light scattering about a small cloud droplet:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5dptE.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5dptE.gif&quot; alt=&quot;Scattering of a radiation beam: processes of reflection (A), refraction (B), refraction and internal reflection (C), and diffraction (D), from http://acmg.seas.harvard.edu/people/faculty/djj/book/bookchap8.html&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The other interactions shown include reflection and refraction. For diffraction, when multiple interactions take place, the diffracted light produces interference patterns. A simple example is shown here for light being diffracted from two sides of a particle:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vp2cQ.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vp2cQ.png&quot; alt=&quot;Illustration of how two points on a droplet surface can scatter light and act as sources of outgoing spherical waves, from https://www.atoptics.co.uk/droplets/corform.htm&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Ultimately, a corona is the result of a great many of these interactions taking place in the presence of a very large number of particles. However, as to pollen coronas in particular, it turns out that the type of particle largely doesn't matter - diffraction is such a major component compared to other optical scattering processes (e.g., reflection or refraction) that a corona may be formed whether the particles are liquid or solid:&#xA;&lt;a href=&quot;https://www.atoptics.co.uk/droplets/corform.htm&quot; rel=&quot;noreferrer&quot;&gt;Corona formation, to a good approximation, needs no knowledge of the droplet interior because the surface scattered waves predominate. It could be water, ink or coal - the pattern is almost the same. It depends primarily on the droplet size, shape and the wavelength of the light.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Pollen, it turns out, sometimes happens to be in a similar size range to cloud droplets. With &lt;a href=&quot;https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/pollen&quot; rel=&quot;noreferrer&quot;&gt;diameters ranging between 15 and 200 μm&lt;/a&gt;, smaller pollen particles can be of similar size as cloud droplets (&lt;a href=&quot;https://scied.ucar.edu/image/aerosols-raindrop-cloud-droplets-sizes&quot; rel=&quot;noreferrer&quot;&gt;~20 μm in diameter)&lt;/a&gt;, allowing them to have similar diffraction properties. In the end, the main difference is that pollen are less uniformly shaped than cloud droplets; preferential orientation as they are suspended in the air can cause the resultant corona to become &lt;a href=&quot;https://www.atoptics.co.uk/droplets/pollen1.htm&quot; rel=&quot;noreferrer&quot;&gt;elongated vertically or have particular bright patches&lt;/a&gt; in some cases.&lt;/p&gt;&#xA;" OwnerUserId="14078" LastActivityDate="2021-07-19T19:49:23.703" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22572" PostTypeId="2" ParentId="17478" CreationDate="2021-07-20T05:11:22.577" Score="0" Body="&lt;p&gt;Not sure if I'm misunderstanding your question.  As stated in the article you referenced, the reason you don't get rained on 50% of the time when the forecast says 50% PoP is because you are much smaller than the size of the model grid-cell.  50% PoP means it could rain anywhere in that grid-cell (usually something close to 10km x 10 km area).  If the PoP gets low, chances are the rain (if any) will be sparse and not necessarily widespread across the grid-cell. If you were the same size as the grid-cell, then you would get wet 50% of the time.&lt;/p&gt;&#xA;&lt;p&gt;If you really want to know if you will get rained on, check the amount of rain forecast. If it's close to the minimum to qualify as rain (0.01 inches), you can rest assured you probably won't get wet, even if the PoP is over 50%.  But, if the amount of forecasted rain gets up above 0.05 to 0.1 inches, it is forecasting a real rain event.  In fact, I just realised that the weather site I use (windy.com) doesn't even report PoP.  Probably because it's not a very useful metric.  After selecting a location, you can use the Windy &amp;quot;compare&amp;quot; feature to see what different weather models predict, which is a better indicator of &amp;quot;probability&amp;quot; than PoP, even though it is qualitative.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2021-07-20T05:11:22.577" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22573" PostTypeId="2" ParentId="22555" CreationDate="2021-07-20T11:20:48.667" Score="6" Body="&lt;p&gt;A 'video disdrometer' is a device for characterizing raindrop size distributions. Professional versions (e.g  &lt;a href=&quot;https://www.distrometer.at/fileadmin/ProduktWebseiten/DIGITAL/distrometer.at/1D_Video_DistrometerWeb.pdf&quot; rel=&quot;noreferrer&quot;&gt;A 1D distrometer&lt;/a&gt;) can use a video camera to image the shadow cast by water droplets moving in front of a bright light. So one DIY approach might be a camera imaging rain drops falling through a gap.&lt;/p&gt;&#xA;&lt;p&gt;Delft university have put up an instructable for an &lt;a href=&quot;https://www.instructables.com/Make-an-acoustic-rain-gauge-disdrometer/&quot; rel=&quot;noreferrer&quot;&gt;audio distrometer&lt;/a&gt;, although their version lacks the signal processing required for quantitative measurements.&lt;/p&gt;&#xA;&lt;p&gt;Both these approaches would probably need access to a tipping bucket rain gauge to calibrate intensities (and maybe a hosepipe to simulate the rain!)&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2021-07-20T11:20:48.667" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22574" PostTypeId="2" ParentId="22555" CreationDate="2021-07-20T18:09:30.473" Score="3" Body="&lt;p&gt;You could connect a funnel to a water wheel.&#xA;The faster it spins the higher intensity of the rain.&lt;/p&gt;&#xA;&lt;p&gt;This sensor was selected randomly, as should not be consider something I specifically endorse.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://usa.banggood.com/TZT-5V-Piezoelectric-Film-Vibration-Sensor-Switch-Module-TTL-Level-Output-Geekcreit-for-Arduino-products-that-work-with-official-Arduino-boards-p-1548339.html?utm_source=googleshopping&amp;amp;utm_medium=cpc_organic&amp;amp;gmcCountry=US&amp;amp;utm_content=minha&amp;amp;utm_campaign=minha-usg-pc&amp;amp;currency=USD&amp;amp;cur_warehouse=CN&amp;amp;createTmp=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://usa.banggood.com/TZT-5V-Piezoelectric-Film-Vibration-Sensor-Switch-Module-TTL-Level-Output-Geekcreit-for-Arduino-products-that-work-with-official-Arduino-boards-p-1548339.html?utm_source=googleshopping&amp;amp;utm_medium=cpc_organic&amp;amp;gmcCountry=US&amp;amp;utm_content=minha&amp;amp;utm_campaign=minha-usg-pc&amp;amp;currency=USD&amp;amp;cur_warehouse=CN&amp;amp;createTmp=1&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="23038" LastActivityDate="2021-07-20T18:09:30.473" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22575" PostTypeId="2" ParentId="22548" CreationDate="2021-07-21T03:25:17.757" Score="1" Body="&lt;p&gt;I have found the answer&lt;/p&gt;&#xA;&lt;p&gt;Geopotential height of ground or water surface is available as a variable (&lt;a href=&quot;https://rda.ucar.edu/datasets/ds084.1/#metadata/detailed.html?_do=y&quot; rel=&quot;nofollow noreferrer&quot;&gt;UCAR variable inventory&lt;/a&gt;).&#xA;It is called 'orography' if you read the file with cfgrib. Somehow it did not appear in variable inventory when read with pygrib ...&lt;/p&gt;&#xA;&lt;p&gt;Alternatively, I could have used &lt;a href=&quot;https://unidata.github.io/MetPy/latest/api/generated/metpy.calc.geopotential_to_height.html?highlight=height#metpy.calc.geopotential_to_height&quot; rel=&quot;nofollow noreferrer&quot;&gt;MetPy&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="23001" LastActivityDate="2021-07-21T03:25:17.757" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22576" PostTypeId="2" ParentId="15349" CreationDate="2021-07-21T05:37:29.237" Score="2" Body="&lt;p&gt;I misunderstood how wet bulb thermometers worked and was confused too... and I'm hopeful that explaining my separate confusion will actually help put emphasis on what's really happening for your question too...&lt;/p&gt;&#xA;&lt;p&gt;I always was taught that as a sling psychrometer was spun, water would keep evaporating by taking heat from the thermometer, and it would keep doing so until the air became saturated and could no longer &amp;quot;take&amp;quot; any more water.&lt;/p&gt;&#xA;&lt;p&gt;But that didn't add up right.  Because a sling psychrometer is moving, bringing in new air continually.&lt;/p&gt;&#xA;&lt;p&gt;I guess I just handwaved it away as &lt;em&gt;&amp;quot;maybe the air envelope around the psychrometer all became saturated&amp;quot;&lt;/em&gt;?&lt;/p&gt;&#xA;&lt;p&gt;But something about that still didn't jive with reality... and maybe more importantly, I would think as long as any extra amount of air can be brought in, the thermometer would keep dropping below the true wet bulb value.  You've got an unlimited supply of air to saturate.&lt;/p&gt;&#xA;&lt;p&gt;But my issue and yours really go back to how the temperature stabilizes.&lt;/p&gt;&#xA;&lt;hr&gt; &#xA;&lt;p&gt;The fourth answer to &lt;a href=&quot;https://www.quora.com/When-is-wet-bulb-temperature-constant-and-why&quot; rel=&quot;nofollow noreferrer&quot;&gt;this Quora question&lt;/a&gt;, by Ashish Kori, as well as &lt;a href=&quot;https://www.youtube.com/watch?v=ktJa5rJzk0Q&quot; rel=&quot;nofollow noreferrer&quot;&gt;this video&lt;/a&gt; from a professor at Lund University in Sweden, are what helped open my eyes better.&lt;/p&gt;&#xA;&lt;p&gt;Basically you're starting with a thermometer covered with a wick that has an excess supply of water, and you &amp;quot;continually expose&amp;quot; it [i.e. by fanning/moving it] to an excess supply of air.  And the air, thermometer, and water all start at the same temperature.&lt;/p&gt;&#xA;&lt;p&gt;The movement encourages evaporation.  The evaporating water takes energy from the water... so the water cools.&lt;/p&gt;&#xA;&lt;p&gt;But as that process continues... the cooler water is now also being continually introduced to air that is warmer than it, so there is a steady transfer of energy back into the water.&lt;/p&gt;&#xA;&lt;p&gt;The movement and unlimited water and air means the process continues until the energy transfer is balanced.  The drier the air, the greater the rate of evaporation, the larger the temperature drop before the energy balances.&lt;/p&gt;&#xA;&lt;hr&gt;&#xA;&lt;p&gt;Why does all that matter?  Because the thermometer is only a bystander in the energy exchange.  The water is what is getting to the wet bulb temperature.&lt;/p&gt;&#xA;&lt;p&gt;Sure the thermometer (both its fluid and casing) will be factors in the energy balance for a time as it does have energy to add to the equation by being briefly warmer than the cooling water... but with the unending evaporation, that bit of extra energy is very quickly forgotten, regardless of how much of it was stored (i.e. the thermometer's heat capacity).&lt;br /&gt;&#xA;A huge heat capacity might mean in theory that it takes slightly longer to reach equilibrium by overcoming the extra energy, but even then it really shouldn't be significant.  (I would think even the thermal conductivity wouldn't be a big factor in a sling psychrometer because of all the mixing motion, so long as the wick isn't so thick as to significantly insulate the thermometer.)&lt;/p&gt;&#xA;&lt;p&gt;Aspirating ensures that any energy buildup (heat capacity storage\conductivity delays) in both dry and wetbulb thermometers is overcome.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;The thermometer is only a bystander in the evaporation, and it must eventually reach the temperature that the water reaches.  The thermometer's heat capacity is unimportant to the continuing energy balance.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2021-07-21T11:04:03.670" LastActivityDate="2021-07-21T11:04:03.670" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22577" PostTypeId="1" AcceptedAnswerId="22578" CreationDate="2021-07-21T15:02:38.103" Score="3" ViewCount="64" Body="&lt;p&gt;Not sure where to post this question, but it struck me the other day that the major driving force behind our modern industrial society is owed nearly entirely to the harnessing of petroleum power in the form of coal and primarily oil products.&lt;/p&gt;&#xA;&lt;p&gt;As I understand it, the current explanation for these deposits' existence is the carboniferous period when plants basically evolved woody structures that allowed them to grow trunks and grow tall. Nothing at the time could digest these structures so they piled up when the trees died and eventually were buried in large amounts and became the various petroleum reserves we find under the surface of the earth.&lt;/p&gt;&#xA;&lt;p&gt;Well, how likely is it that this specific path of evolution (or lack thereof on the part of organisms that would consume the dead plants) happens on many other planets, resulting in essentially a gigantic reserve of &amp;quot;free&amp;quot; energy buried and waiting to be exploited by a society of intelligent organisms?&lt;/p&gt;&#xA;&lt;p&gt;Is this almost a necessary occurrence for industrial civilization? Couldn't this explain the apparent lack of interstellar civilizations? That it's such a rare thing to have all this free easy access energy already stored up for a civilization to access?&lt;/p&gt;&#xA;" OwnerUserId="23043" LastEditorUserId="6467" LastEditDate="2021-07-21T22:50:05.113" LastActivityDate="2021-07-21T22:50:05.113" Title="Is it incredibly unlikely that industrial societies emerge elsewhere in the galaxy due to lack of petroleum or similar substance?" Tags="|geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22578" PostTypeId="2" ParentId="22577" CreationDate="2021-07-21T15:42:58.460" Score="4" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;As I understand it, the current explanation for these deposits' existence is the carboniferous period when plants basically evolved woody structures that allowed them to grow trunks and grow tall.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is a minor point, but you're writing about coal rather than petroleum. Most geologists think petroleum is also of biogenic origin, but resulted from sea-based rather than land-based life.&lt;/p&gt;&#xA;&lt;p&gt;Regarding the larger issue,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Is this almost a necessary occurrence for industrial civilization?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is the Rare Earth Hypothesis versus the hypothesis that life (including intelligent life) is common. The answer for now is we do not know. Extrapolating from a sample size of one is typically a bad idea. What we do know is that planets are common.&lt;/p&gt;&#xA;&lt;p&gt;Whether planets that can support even primitive life are common, we do not know. Whether planets that cam support intelligent life are common, we do not know. Whether intelligent life can pass beyond the chimpanzee / dolphin / crow / octopus stage (these are all intelligent species) to something that resembles human intelligence, we do not know. Whether human-level intelligence requires resources like coal / petroleum / metals to become space-faring or space-communicative, we do not know.&lt;/p&gt;&#xA;&lt;p&gt;There are lots of science fiction stories of resource-poor planets where that prevented intelligent species from advancing. There are also lots of science fiction stories of resource-poor planets where the intelligent species overcame those limits. But that's science fiction. Science fact is that we do not know.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2021-07-21T15:42:58.460" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22579" PostTypeId="2" ParentId="22558" CreationDate="2021-07-21T19:39:51.187" Score="2" Body="&lt;p&gt;I think you might be getting terms mixed up. Let's follow the standard convention of &lt;a href=&quot;https://en.wikipedia.org/wiki/Ensemble_Kalman_filter#Kalman_filter&quot; rel=&quot;nofollow noreferrer&quot;&gt;data assimilation&lt;/a&gt; and call your model output from the (&lt;span class=&quot;math-container&quot;&gt;$k^{\text{th}}$&lt;/span&gt; parameterization/forcing) &lt;span class=&quot;math-container&quot;&gt;$X_k$&lt;/span&gt; and the observations &lt;span class=&quot;math-container&quot;&gt;$y$&lt;/span&gt;. For simplicity's sake, let's just say that the observation operator is unitary (&lt;span class=&quot;math-container&quot;&gt;$H=I$&lt;/span&gt;). The equation for the Root Mean Squared Error (RMSE) for the &lt;span class=&quot;math-container&quot;&gt;$k^{\text{th}}$&lt;/span&gt; model (&lt;span class=&quot;math-container&quot;&gt;$k$&lt;/span&gt; could be a unique index that is a combination of forcing and parameterization) is &lt;span class=&quot;math-container&quot;&gt;$$RMSE_k=\sqrt{\sum_i\frac{\left(x_{i,k}-y_i\right)^2}{N}}$$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$x_i$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$y_i$&lt;/span&gt; are indices paired 'samples' from &lt;span class=&quot;math-container&quot;&gt;$X$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$Y$&lt;/span&gt; respectively. The sampling that you use performs RMSE sampled over time, but you can just as easily sample over space.&lt;/p&gt;&#xA;&lt;p&gt;What is a metric that is easily comparable to RMSE that measures model variation? Let's follow what you suggested (more for the narrative). If we let the mean state for the &lt;span class=&quot;math-container&quot;&gt;$k^{\text{th}}$&lt;/span&gt; model be &lt;span class=&quot;math-container&quot;&gt;$\bar{x}_k=\frac{1}{N}\sum_i x_{i,k}$&lt;/span&gt; then the formula you suggested would actually be &lt;span class=&quot;math-container&quot;&gt;$$\sqrt{\sum_i\frac{\left(x_{i,k}-\bar{x}_k\right)^2}{N}}$$&lt;/span&gt;. Now that looks a lot like the formula for the &lt;a href=&quot;https://en.wikipedia.org/wiki/Standard_deviation&quot; rel=&quot;nofollow noreferrer&quot;&gt;standard deviation&lt;/a&gt;. Rather, the way that we notated this formula shows the model-dependent standard deviation fluctuates on time. However, if we make a model mean variable &lt;span class=&quot;math-container&quot;&gt;$\hat{x}_i=\frac{1}{N}\sum_k x_{i,k}$&lt;/span&gt;, then we can determine how much the different forcings and parameterizations cause the output to vary with time: &lt;span class=&quot;math-container&quot;&gt;$$\sigma_i=\sqrt{\sum_k\frac{\left(x_{i,k}-\hat{x}_i\right)^2}{N}}$$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;So really, your formula should look like (reverting back to your notation): &lt;span class=&quot;math-container&quot;&gt;$$\frac{RMSE}{\sqrt{\frac{1}{N}(Y_{i,j}(t_k)-\bar{Y_j}(t_k))^2}}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now, I think your idea is fine, but the interpretation is incorrect. You can legitimately have a number that is greater than one (for example, if you see no difference, the standard deviation is 0, therefore your metric reaches infinity). You also cannot say if the inclusion of the parameterization makes the model better based on this metric. That would require the examining the RMSE of each parameterization + forcing. Such an experiment shows relative roles that the parameterizations/forcings of similar kind have in creating the number of possible model outputs that could be causing model errors.&lt;/p&gt;&#xA;&lt;p&gt;An example that I know of where such an analysis was conducted was &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2018MS001457&quot; rel=&quot;nofollow noreferrer&quot;&gt;Thomas et al. (2019)&lt;/a&gt;. In it, the RMSE was computed and the model standard deviation was compared, with the standard deviation being smaller than the RMSE (therefore leading to numbers greater than 1, per the corrections [namely the square root] to your logic).&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-07-21T19:39:51.187" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22580" PostTypeId="1" CreationDate="2021-07-22T03:56:05.397" Score="1" ViewCount="65" Body="&lt;p&gt;Some regions have monsoon conditions, a seasonal reversal of wind due to the heating and cooling of major land masses. This is true of east Asia in particular; according to &lt;a href=&quot;https://science.jrank.org/pages/4439/Monsoon-monsoons-South-China-Japan.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://science.jrank.org/pages/4439/Monsoon-monsoons-South-China-Japan.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The monsoons of China and Japan are strongly affected by the huge land mass of Siberia. During the winter, the interior of Siberia becomes extremely cold. Cold air is dense, so a cold area of high pressure forms, where the air sinks from aloft. When it reaches the surface, the air spreads outward in all directions. The result is a dry winter monsoon that blows from the north through south China and southeast Asia. The same circulation affects northern China, Japan and Taiwan, where the prevailing wind is from the northwest.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;But that description seems like it should also apply to North America, with the interior of Canada becoming likewise extremely cold. Why is the east coast of North America not similarly subject to a dry winter monsoon?&lt;/p&gt;&#xA;&lt;p&gt;(I have seen it argued that this is because the polar vortex prevents cold air spilling down over North America. But then the question becomes, why does the polar vortex behave this way over that continent, but not over Asia?)&lt;/p&gt;&#xA;" OwnerUserId="7911" LastEditorUserId="6298" LastEditDate="2021-07-22T08:52:28.283" LastActivityDate="2021-07-22T08:52:28.283" Title="Why is there no American dry winter monsoon?" Tags="|climate|geography|wind|seasons|monsoon|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22582" PostTypeId="2" ParentId="17567" CreationDate="2021-07-22T17:12:28.700" Score="0" Body="&lt;p&gt;Your assumption about water that reach the lower point in mines is correct, in fact in the older mines that develop let's say in a mountain they dug a lower level tunnel that collect all the water of the mine, this tunnel can run several miles like one in Sardinia (Italy) that reach the sea at 14 Km.&lt;/p&gt;&#xA;&lt;p&gt;This method have the obvious limitation that you cannot go under this bottom level, so you reach a point when you have to pump water out to your daring tunnel.&lt;/p&gt;&#xA;&lt;p&gt;Mine shaft also have a deeper bottom to collect water, in older mines with a relative low water income they run a &amp;quot;bucket&amp;quot; in the bottom of the shaft to take water as in a normal well.&lt;/p&gt;&#xA;&lt;p&gt;In the modern times you have always the need to collect water in a point where you have installed your pump, and you do this digging some ditch along the tunnel for example.&lt;/p&gt;&#xA;&lt;p&gt;Water can be very dangerous because digging tunnels you can encounter large mass of water, this happen for example during the dig of many tunnels that go trough Alps.&lt;/p&gt;&#xA;" OwnerUserId="23015" LastActivityDate="2021-07-22T17:12:28.700" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22583" PostTypeId="2" ParentId="7813" CreationDate="2021-07-22T17:27:32.697" Score="2" Body="&lt;p&gt;I think the answer to your question is hidden in the question itself, let me explain...&lt;/p&gt;&#xA;&lt;p&gt;Because technology and every innovation is the convergence of thinking of many people over the years, the fact that we use metals to build tools prove that metal is the good choice.&lt;/p&gt;&#xA;&lt;p&gt;For your question, i suppose you want recreate some &amp;quot;primitive technology&amp;quot; (i know the amazing channel that you are talking about), so the obvious choice is find metal oxides because sulphides need a very complex metallurgy and in some expect dangerous to your health.&lt;/p&gt;&#xA;&lt;p&gt;If your question is related to survival aspects.. If I found myself as a survival of some kind of apocalypse.. I will collect steel and other metals to ruins instead of mining, no doubt.&lt;/p&gt;&#xA;&lt;p&gt;back to your question Ivory and bones are a good material to build some categories of tools.&lt;/p&gt;&#xA;" OwnerUserId="23015" LastActivityDate="2021-07-22T17:27:32.697" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22584" PostTypeId="2" ParentId="14832" CreationDate="2021-07-22T17:34:28.660" Score="0" Body="&lt;p&gt;I want to contribute to the excellent answers already given pointing out two things:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;external color of a rock (altered) can be different from the rock minerals colours&lt;/li&gt;&#xA;&lt;li&gt;the powder of a mineral can be of a different color of the mineral.. for example some metallic color sulphides of zinc have a red powder if scratched.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="23015" LastActivityDate="2021-07-22T17:34:28.660" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22585" PostTypeId="2" ParentId="7813" CreationDate="2021-07-22T20:43:00.863" Score="2" Body="&lt;p&gt;Get a book on extractive metallurgy. One thing strikes me is that &amp;quot;primitives'&amp;quot; were pretty sophisticated.  Also their technology was developed over generations by many people. I think starting with copper as ancients did would be a good idea. Iron is much more common but steel requires about 2900 °F (1600 °C). Cast iron, only about 2200 °F (1200 °C), but you can only make brittle castings. To get from cast iron to steel requires a history of extractive metallurgy, time and work. Although the ore is very rare, tin/pewter would be much easier to handle . And if you have copper, then you have bronze.  As for the scarcity of tin, keep in mind people from around the Mediterranean came to Cornwall for tin for thousands of years. Maybe just get some scrap steel , heat it up and play blacksmith; see if you can figure out how to heat-treat it. When reading this, I see I was not clear; Steel making is three difficult, laborious steps ; 1- make pig iron, 2- make it into steel, 3- heat-treat the steel to useful properties. The third step is not as difficult as the other two . For copper, you smelt it and you have copper ready to make into a useful shape.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastEditorUserId="2470" LastEditDate="2021-07-24T04:20:11.807" LastActivityDate="2021-07-24T04:20:11.807" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22587" PostTypeId="2" ParentId="19862" CreationDate="2021-07-23T07:07:12.123" Score="2" Body="&lt;p&gt;&lt;strong&gt;The tilt is not the real reason for the perpetually warm, humid weather in the tropics.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;If the Earth tilted 90 degrees, the entire planet wouldn't become super hot and &amp;quot;tropical&amp;quot;, seasons would just vary a lot more.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthsky.org/space/what-are-the-seasons-like-on-uranus/&quot; rel=&quot;nofollow noreferrer&quot;&gt;See Uranus&lt;/a&gt;, which is tilted about 98 degrees, and so the entire planet has a season of full sunlight and a season of full shade.  Being so far from the sun, perhaps the impacts aren't huge... but you can imagine if that were Earth, everywhere would face long hot periods and long cold periods, and the &amp;quot;tropics&amp;quot; as the region between the two lines wouldn't feel very &amp;quot;tropical&amp;quot; overall.&lt;/p&gt;&#xA;&lt;p&gt;Likewise a planet with no tilt would basically have the same incoming solar radiation throughout, &lt;a href=&quot;https://earthscience.stackexchange.com/a/10073/6298&quot;&gt;with perpetual climate then only kindled by the curving of the Earth&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;hr&gt;&#xA;&lt;p&gt;&lt;strong&gt;Why do we define tropics that way then?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Well the axial tilt of Earth &lt;a href=&quot;https://en.wikipedia.org/wiki/Axial_tilt#History&quot; rel=&quot;nofollow noreferrer&quot;&gt;was discovered&lt;/a&gt; long before a conceptual understanding of weather was determined.  The word tropic was &lt;a href=&quot;https://www.etymonline.com/word/tropic&quot; rel=&quot;nofollow noreferrer&quot;&gt;originally about the tilt and not the weather/region&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Meteorology as a science really &lt;a href=&quot;https://earthobservatory.nasa.gov/features/WxForecasting/wx2.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;didn't really advance a ton until the late 1800s&lt;/a&gt;, when the &lt;a href=&quot;https://en.wikipedia.org/wiki/Telegraphy&quot; rel=&quot;nofollow noreferrer&quot;&gt;telegraph&lt;/a&gt; finally started allowing more reasonable collection of measurements over large regions.  Hadley was actually &lt;a href=&quot;https://en.wikipedia.org/wiki/Hadley_cell#History_of_discovery&quot; rel=&quot;nofollow noreferrer&quot;&gt;well ahead of his time&lt;/a&gt;, proposing the loose explanation in the mid 1700s, but the rough concept didn't reach popularity until the 1800s.  &lt;a href=&quot;https://i.stack.imgur.com/2XW85.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Regardless, the word tropic was in use long before Hadley's theory&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;By the 1600s exploration had a &lt;a href=&quot;https://en.wikipedia.org/wiki/Mercator_1569_world_map&quot; rel=&quot;nofollow noreferrer&quot;&gt;fairly through picture&lt;/a&gt; of basically all the Earth outside the polar regions.  And the lines for the Tropics of Cancer\Capricorn were already on that &lt;a href=&quot;https://en.wikipedia.org/wiki/Mercator_1569_world_map&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mercator's map&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Exploration and colonization also not only made astronomy and navigation of wider interest to the European scientific realm, but those colonies and imports also sparked particular societal interest towards many warm, moist regions (West Indies, East Indies, Africa, Central\South America).  And so tropics rapidly came to be refer to the general region between the two lines, &lt;a href=&quot;https://www.etymonline.com/word/tropic&quot; rel=&quot;nofollow noreferrer&quot;&gt;apparently by 1520&lt;/a&gt;.  And its use as imagery &lt;a href=&quot;https://www.etymonline.com/word/tropical&quot; rel=&quot;nofollow noreferrer&quot;&gt;quickly associated it with that region's weather&lt;/a&gt;.&lt;br /&gt;&#xA;(Such imagery is common, just as Arctic &lt;a href=&quot;https://www.etymonline.com/word/arctic&quot; rel=&quot;nofollow noreferrer&quot;&gt;quickly became associated with cold weather&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;So we had climate regions long before we had explanations for why they existed.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;They're called the tropics, which is indeed a term from axial tilt.  But that isn't because the tilt causes the tropics weather.&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;See &lt;a href=&quot;https://english.stackexchange.com/questions/539263/origin-of-word-tropic-from-tropic-of-capricorn-tropic-of-cancer&quot;&gt;this English StackExchange question&lt;/a&gt; on the word's history for a bit more detail on the etymology.&lt;/p&gt;&#xA;&lt;hr&gt;&#xA;&lt;p&gt;&lt;strong&gt;So what explains tropical weather?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Being heated &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_irradiance#/media/File:InsolationTopOfAtmosphere.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;fairly consistently&lt;/a&gt; at significant amounts in low latitudes certainly explains the warm temperatures we think of as tropical.  So in a sense the lack of large tilt does connect to that.  Though that heating difference is really due directly to the curvature of the Earth, so not in any real kind of 23.5°ish kind of way.&lt;/p&gt;&#xA;&lt;p&gt;Rainy weather in the tropics doesn't really need the Hadley Circulation either; it is likewise driven by all the warm, less dense air.  Edmond Halley &lt;a href=&quot;http://earthguide.ucsd.edu/virtualmuseum/climatechange1/08_1.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;had proposed this idea&lt;/a&gt; in the 1600s.  Warm air at equators = rising, stormy.  Cold air at the poles = sinking, &lt;a href=&quot;https://www.aurora-expeditions.com/blog/is-antarctica-a-desert/&quot; rel=&quot;nofollow noreferrer&quot;&gt;desert-like&lt;/a&gt;.  Only need that basic idea, don't need the more complex cells of Hadley.  But this also doesn't explain the extent of the tropics to much detail.&lt;/p&gt;&#xA;&lt;p&gt;What does need the extra Hadley cell to explain is the wind direction in the &amp;quot;tropics&amp;quot;, and why they are limited so much, such that there's sinking air at 30°.  The Hadley shows that conservation of angular momentum means air can't go directly from the tropics to the poles aloft without stopping, and so the sinking results in 4 latitudes per hemisphere of alternated weather... while Halley could only explain 2 of these temperature zones in each hemisphere.&lt;/p&gt;&#xA;&lt;p&gt;Do note that there are 4 zones of weather in a hemisphere due to Hadley, not 3, which in a sense throws a kink in your question...&lt;br /&gt;&#xA;The dry region is &lt;a href=&quot;https://earthscience.stackexchange.com/questions/388/why-does-the-hadley-cell-descend-at-30-degrees&quot;&gt;setup to be at roughly 30° North\South&lt;/a&gt; from Hadley.  But being CENTERED on that latitude, it means real &amp;quot;tropical&amp;quot; weather (including persistent copious rainfall) wouldn't be 0-30, but much less.   If each of the seven resulting latitudinal zones is a similar 30° in size, the tropics would be more like 15°S to 15°N.  [There's no absolute requirement for equal sized zones; slow sinking air is often spread over a much larger area than rapid rising air... such as the comparison of the area of deep updrafts in a hurricane to the subsidence surrounding the storm.  In addition disproportionate surface areas and the impact of temperatures on density further complicate blip the balance... but it's still seems reasonable as a whole] With the seasonal shift of weather (just as the zone of arctic fronts and cold air shifts with season, so &lt;a href=&quot;https://www.youtube.com/watch?v=Z0yQuq4QdwM&quot; rel=&quot;nofollow noreferrer&quot;&gt;does the ITCZ&lt;/a&gt;) (the movement of which &lt;a href=&quot;https://earthscience.stackexchange.com/questions/4309/why-does-the-inter-tropical-convergence-zone-shift&quot;&gt;IS caused by the tilt&lt;/a&gt;), it means if you envision tropical as being yearround rain... there's not a great size to it.  Just how tropical places are (in terms of wetness) comes down a great deal to local geography... certainly the cells don't jump out too cleanly on an average rainfall map...&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tHXRM.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tHXRM.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;(From &lt;a href=&quot;https://www.usgs.gov/media/images/generalized-world-precipitation-map&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;hr&gt;&#xA;&lt;p&gt;&lt;strong&gt;TL;DR&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;So tropical weather isn't set as 23.5°N to 23.5°S via the tilt.  Tilt controls the seasonal shift of weather, but not really the size of climate zones or their types.&lt;/p&gt;&#xA;&lt;p&gt;And tropical weather also isn't set as 30°N to 30°S via the Hadley cell/angular momentum.  The Hadley does setup the types and sizes of the climate zones, but that means they're smaller.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Generally the true &amp;quot;deep tropics&amp;quot; are less than both.&lt;/strong&gt;   (After all the Sahara is basically &lt;a href=&quot;https://www.geologyin.com/2018/04/the-sahara-desert-expanded-by-10-in.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;centered near to the Tropic of Cancer&lt;/a&gt;).  If each climate zone is considered roughly equal in latitudinal size, the tropics boundaries due to the Hadley Cell would only be more like 15°N to 15°S.  And the shifts caused by the tilt then make it yet more complex in defining, depending upon how much rainfall variability you're willing to accept.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2021-07-25T23:43:58.367" LastActivityDate="2021-07-25T23:43:58.367" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22588" PostTypeId="1" CreationDate="2021-07-23T08:25:57.240" Score="1" ViewCount="27" Body="&lt;p&gt;What variables are necessary to calculate carbon sequestration on densely population tree cover over a large spatial range?&lt;/p&gt;&#xA;&lt;p&gt;I wish to work on a project that has been proposed to me and my team at work. We are currently at the stage of determining it's possibility given that we are only junior analysts, and not earth scientists, though some of us have a background in environmental/earth science.&lt;/p&gt;&#xA;&lt;p&gt;As far as I am aware, the calculation required for carbon sequestration of trees requires the trees breast height, age,biomas below and above ground and soil carbon.&lt;/p&gt;&#xA;&lt;p&gt;Given that I am able to collect data on Tree cover percentage of a large spatial range say Europe from the MODIS landsat, would it be possible to calculate carbon sequestration from this alone?&lt;/p&gt;&#xA;&lt;p&gt;Link: &lt;a href=&quot;https://lpdaac.usgs.gov/products/mod44bv006/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://lpdaac.usgs.gov/products/mod44bv006/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;If I am to collect soil biomass at some depth how would this contribute to the dataset in calculating carbon sequestration?&lt;/p&gt;&#xA;&lt;p&gt;I am happy to receive some articles that can help me formulate this together or other datasets that would suit my purpose. Otherwise, please let me know if this is not possible given the data provided.&lt;/p&gt;&#xA;" OwnerUserId="23050" LastActivityDate="2021-07-23T08:25:57.240" Title="Calculating carbon sequestration on the percentage of tree cover" Tags="|co2|forest|carbon|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22589" PostTypeId="1" CreationDate="2021-07-23T09:18:16.323" Score="3" ViewCount="433" Body="&lt;p&gt;Thinking about the movie &lt;em&gt;Dune&lt;/em&gt; (this is not a sci fi question) got me to wondering.&lt;/p&gt;&#xA;&lt;p&gt;In the theoretical situation where you had a desert of sand with an unlimited depth here on Earth. At what depth would the pressure of the sand above compress the sand particles into something that could no longer be called sand, and at what depth would a layer of stone/rock be formed?&lt;/p&gt;&#xA;&lt;p&gt;Would this mean there is a theoretical maximum depth a dessert can only ever be before it hits a layer of bedrock formed by the pressure of the sand above?&lt;/p&gt;&#xA;" OwnerUserId="23051" LastEditorUserId="2470" LastEditDate="2021-07-24T04:22:57.637" LastActivityDate="2021-07-24T04:22:57.637" Title="At what theoretical depth of sand would pressure turn the sand into rock?" Tags="|geology|desert|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22590" PostTypeId="1" CreationDate="2021-07-23T10:18:46.197" Score="4" ViewCount="402" Body="&lt;p&gt;I don't know much about science, I'm just curious about how much warming a certain amount of CH&lt;sub&gt;4&lt;/sub&gt; would cause compared to a similar amount of CO&lt;sub&gt;2&lt;/sub&gt; (both 5 GtC).&#xA;I'm sorry if the question sounded a bit confusing, I'm just a layman trying to learn more about global warming and climate change.&lt;/p&gt;&#xA;" OwnerUserId="22045" LastEditorUserId="2470" LastEditDate="2021-07-24T04:24:06.027" LastActivityDate="2021-11-12T20:44:36.783" Title="How much would 5 gigatons of methane warm the atmosphere compared to 5 gigatons of CO2 if both were released in one go?" Tags="|meteorology|atmosphere|climate-change|atmospheric-radiation|solar-terrestrial-physics|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="22591" PostTypeId="1" CreationDate="2021-07-23T14:37:23.557" Score="4" ViewCount="2346" Body="&lt;p&gt;One of my friends told me quite seriously that Gaia had evolved humans to burn the fossil fuels and thus stop the earth running out of CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Leaving aside the obvious nonsense it did raise an interesting question, what stops us running out of CO&lt;sub&gt;2&lt;/sub&gt;?  Apart from volcanism are there any processes that return carbon captured in fossil fuels and limestone to the atmosphere? Is it plausible that the planet could run so low on atmospheric carbon that plants couldn't photosynthesize?&lt;/p&gt;&#xA;" OwnerUserId="23054" LastEditorDisplayName="user20559" LastEditDate="2021-07-28T12:00:50.980" LastActivityDate="2021-08-07T16:12:05.857" Title="When would the earth run out of carbon dioxide without man made climate change?" Tags="|atmosphere|co2|carbon-cycle|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22592" PostTypeId="1" CreationDate="2021-07-23T21:34:35.830" Score="1" ViewCount="84" Body="&lt;p&gt;I came across a video where a piece of land was seen rising very rapidly after rain. The land got elevated within a few minutes by atleast a meter.&lt;br /&gt;&#xA;Can anyone suggest possible mechanisms?&lt;/p&gt;&#xA;&lt;p&gt;I am sharing complete video link through my &lt;a href=&quot;https://drive.google.com/drive/folders/1ZKVahlYXxcMqxwRsyP2JcHrAik2diYGG?usp=sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;google drive&lt;/a&gt;.&#xA;A clipped part of it is also available here &lt;a href=&quot;https://www.youtube.com/watch?v=ezL7_FW36as&quot; rel=&quot;nofollow noreferrer&quot;&gt;on you tube&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5413" LastEditorUserId="5413" LastEditDate="2021-07-24T05:49:44.850" LastActivityDate="2021-07-24T05:49:44.850" Title="Rapidly rising land after rain seen in India? What can cause this?" Tags="|geology|rain|" AnswerCount="0" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="22593" PostTypeId="2" ParentId="22591" CreationDate="2021-07-23T23:41:56.270" Score="3" Body="&lt;p&gt;The answer is &lt;em&gt;The Carbon Cycle&lt;/em&gt;, which includes carbon cycling between atmosphere and oceans, vegetation and soils ensure the Earth does not run out. Volcanoes add very little in proportion to Plant Respiration or Soil Decomposition or Ocean Loss (or even fossil fuel burning) - but unlike those, volcanic CO&lt;sub&gt;2&lt;/sub&gt; (and similarly, fossil fuel CO&lt;sub&gt;2&lt;/sub&gt;) is not accompanied by processes like Photosynthesis, Litterfall or Ocean Uptake that draw CO&lt;sub&gt;2&lt;/sub&gt; out of the atmosphere. However there is some ongoing loss of carbon to Burial to Sediments.&lt;/p&gt;&#xA;&lt;p&gt;Without the fossil fuel burning the fluxes (flows) were close to being in equilibrium, without ongoing consumption and enduring loss of atmospheric CO&lt;sub&gt;2&lt;/sub&gt; -&lt;br /&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/xnn6y.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xnn6y.jpg&quot; alt=&quot;Global Carbon Cycle&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="18145" LastEditDate="2021-07-24T06:40:35.853" LastActivityDate="2021-07-24T06:40:35.853" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22594" PostTypeId="2" ParentId="22589" CreationDate="2021-07-24T04:15:22.603" Score="2" Body="&lt;p&gt;What you are asking about is the formation of &lt;a href=&quot;https://en.wikipedia.org/wiki/Sandstone&quot; rel=&quot;nofollow noreferrer&quot;&gt;sandstone&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;There is more to the process than just applying pressure; chemical changes,  pressure, water and heat are all involved in the process.&lt;/p&gt;&#xA;&lt;p&gt;When sand deposits accumulate they undergo a process called &lt;a href=&quot;https://en.wikipedia.org/wiki/Diagenesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;diagenesis&lt;/a&gt;, which involves,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;physical and chemical changes in sediments first caused by water-rock interactions, microbial activity and compaction after their deposition. Increased pressure and temperature only start to play a role as sediments become buried much deeper in the Earth's crust.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;During the process of diagenesis porosity of the sediment decreases.&lt;/p&gt;&#xA;&lt;p&gt;The early stages of diagenesis can take place a depths of tens of meters.&lt;/p&gt;&#xA;&lt;p&gt;As the sand undergoes additional compaction resulting from further accumulation of sand,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;the sand comes under increasing pressure from overlying sediments. Sediment grains move into more compact arrangements, ductile grains (such as mica grains) are deformed, and pore space is reduced. In addition to this physical compaction, chemical compaction may take place via &lt;a href=&quot;https://en.wikipedia.org/wiki/Pressure_solution&quot; rel=&quot;nofollow noreferrer&quot;&gt;pressure solution&lt;/a&gt;. Points of contact between grains are under the greatest strain, and the strained mineral is more soluble than the rest of the grain. As a result, the contact points are dissolved away, allowing the grains to come into closer contact.&lt;/p&gt;&#xA;&lt;p&gt;Mechanical compaction takes place primarily at depths less than 1,000 meters. Chemical compaction continues to depths of 2,000 meters, and most cementation takes place at depths of 2,000–5,000 meters.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-07-24T04:15:22.603" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22598" PostTypeId="2" ParentId="21294" CreationDate="2021-07-25T01:51:24.893" Score="-1" Body="&lt;p&gt;it looks like a gastropod, as there are no septa. Maybe it is Malayaspira, which is Ordovician&lt;/p&gt;&#xA;" OwnerUserId="23064" LastActivityDate="2021-07-25T01:51:24.893" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22599" PostTypeId="1" CreationDate="2021-07-25T06:31:24.197" Score="1" ViewCount="659" Body="&lt;p&gt;I have heard Neil degrasse Tyson say the earth is pear shaped but I can’t find any source for this.&lt;/p&gt;&#xA;&lt;p&gt;We all know the earth has an equatorial bulge because it spins but Neil says “it’s slightly wider below the equator than above it”&lt;/p&gt;&#xA;&lt;p&gt;I’d just like someone to explain why this is and if there is any source that has measured this.&lt;/p&gt;&#xA;" OwnerUserId="22946" LastActivityDate="2021-07-25T06:31:24.197" Title="Has the pear shape of the earth been measured?" Tags="|geodesy|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22600" PostTypeId="1" CreationDate="2021-07-25T18:56:57.053" Score="18" ViewCount="10526" Body="&lt;p&gt;In the question &lt;em&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/19134/does-gravity-increase-the-closer-to-the-core-you-get&quot;&gt;Does gravity increase the closer to the core you get?&lt;/a&gt;&lt;/em&gt;, it was determined that gravity reduces to zero at the center of the Earth.  That is logical.&lt;/p&gt;&#xA;&lt;p&gt;However if pressure is proportional to mass and gravity, then would pressure also reduce to zero at the center of the Earth?   If all the atoms in the center of the Earth are essentially weightless (equal gravity on all sides), then how can there be any pressure?&lt;/p&gt;&#xA;&lt;p&gt;And if there is no pressure, just weightless atoms, then could voids or bubbles form in the center of the Earth?   And if a bubble did form, would its ‘skin’ not feel more gravity on the outward side of the bubble, thus inducing the void to grow?&lt;/p&gt;&#xA;&lt;p&gt;And if such a hypothetical void did grow at the center of the Earth, at what size would it stabilize?&lt;/p&gt;&#xA;" OwnerUserId="23065" LastEditorUserId="2470" LastEditDate="2023-03-01T00:51:00.017" LastActivityDate="2023-03-01T00:51:00.017" Title="What is the pressure at the center of the Earth?" Tags="|geology|geophysics|gravity|pressure|" AnswerCount="5" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22601" PostTypeId="2" ParentId="22600" CreationDate="2021-07-25T19:42:20.087" Score="37" Body="&lt;p&gt;It is the pressure &lt;strong&gt;gradient&lt;/strong&gt; that is proportional to the local gravitational force. When that force is integrated over a distance, the pressure gradient is integrated to accumulate a total pressure.&lt;/p&gt;&#xA;&lt;p&gt;The maximum occurs at the point towards which gravity is directed in a spherical mass, which is the center. True, gravity at that point is zero, but it and therefore the pressure gradient have already been integrated over the whole radius (and mass) of the Earth. Instead of zero, the pressure at the center will be a maximum.&lt;/p&gt;&#xA;&lt;p&gt;The pressure at the center of Earth is about 360 GPa &lt;a href=&quot;https://www.researchgate.net/publication/228377528_THE_INNER_STRUCTURE_OF_THE_EARTH/citation/download&quot; rel=&quot;noreferrer&quot;&gt;[1]&lt;/a&gt;. Note carefully that, as expected where the gravity is locally zero, the total pressure levels off until its &lt;em&gt;gradient&lt;/em&gt; is zero at the center; but the total pressure itself is maximized there instead of dropping to zero.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/sTl4X.png&quot; alt=&quot;enter image description here&quot; /&gt;&#xA;From Ref. [1].&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;1.&#xA;Lajos Volgyesi, M Moser; &amp;quot;The Inner Structure of the Earth&amp;quot;, Periodica Polytechnica Chemical Engineering (1982) &lt;strong&gt;26&lt;/strong&gt;(3).&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;Addendum:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;A couple additional features should be noted in the above plot. First, it was mentioned above that the pressure gradient is proportional to the local gravitational force. Actually it is proportional to force per unit &lt;em&gt;volume&lt;/em&gt;, whereas gravity at any point is a certain amount of force per unit &lt;em&gt;mass&lt;/em&gt;. So if there is an increase in density (more mass packed into the same volume), the gradient jumps. Thus is seen in the plot where the mantle meets the denser material in the core (rock --&amp;gt; iron).&lt;/p&gt;&#xA;&lt;p&gt;Second, the maximum pressure noted above is 360 GPa. This is comparable to and maybe larger than the bulk modulus of the materials that make up the Earth; for instance &lt;a href=&quot;https://www.britannica.com/science/bulk-modulus&quot; rel=&quot;noreferrer&quot;&gt;Encyclopedia Britannica&lt;/a&gt; gives a bulk modulus of only 160 GPa for steel (an iron-based alloy) under ambient conditions. This means the pressure required to balance gravity deep inside Earth is sufficient to compress the material and make it more dense than it normally would be. In fact this compression causes Earth to become denser than Mercury, even though the latter is overwhelmingly iron. Mercury is smaller and less massive than Earth, so it cannot generate as much compression from its gravity.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2021-07-28T23:43:06.727" LastActivityDate="2021-07-28T23:43:06.727" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22602" PostTypeId="1" AcceptedAnswerId="22611" CreationDate="2021-07-26T10:59:56.080" Score="5" ViewCount="184" Body="&lt;p&gt;The motion of &lt;a href=&quot;https://en.wikipedia.org/wiki/Typhoon_In-fa&quot; rel=&quot;noreferrer&quot;&gt;Typhoon In-fa&lt;/a&gt; or Fabian made a hard 90 degree left turn and started heading towards Taiwan, slowed to 5 km/hr before reaching it, then took a hard 90 degree right turn and proceeded along its original direction.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What is it that causes these &lt;em&gt;apparently&lt;/em&gt; abrupt 90 degree turns?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Below captured from &lt;a href=&quot;https://www.cwb.gov.tw/V8/E/P/Typhoon/TY_NEWS.html#collapse-A1&quot; rel=&quot;noreferrer&quot;&gt;Central Weather Bureau&lt;/a&gt;. The &lt;a href=&quot;https://www.cwb.gov.tw/Data/typhoon/TY_NEWS/Download_PTA_202107260600_enus.png&quot; rel=&quot;noreferrer&quot;&gt;original image&lt;/a&gt; dated &lt;code&gt;2021-07-26 06:00&lt;/code&gt; (UTC I assume).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/k7ZVK.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/k7ZVK.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2021-07-26T17:42:20.493" Title="What makes a typhoon suddenly turn by 90 degrees? (e.g. 2021 In-fa/Fabian)" Tags="|meteorology|weather-forecasting|tropical-cyclone|severe-weather|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22603" PostTypeId="2" ParentId="13727" CreationDate="2021-07-26T11:48:21.320" Score="1" Body="&lt;p&gt;I listed &lt;a href=&quot;https://www.paperpublications.org/upload/book/Harnessing%20of%20Kinetic%20Energy%20of%20Raindrops-380.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Harnessing of Kinetic Energy of Raindrops&lt;/em&gt;&lt;/a&gt; as a reference when I answered one of your recent questions, &lt;em&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/22555/ways-to-make-a-how-hard-is-it-raining-detector-for-personal-use&quot;&gt;Ways to make a “How hard is it raining?” detector for personal use?&lt;/a&gt;&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Serendipitously, that reference has information relevant to this question.&lt;/p&gt;&#xA;&lt;p&gt;The size and velocities of rain drops varies according to the type of rainfall event.&lt;/p&gt;&#xA;&lt;p&gt;For &lt;strong&gt;Light Stratiform Rain&lt;/strong&gt;, light rain had drops 0.5 mm in size (diameter) and a terminal velocity of 2.06 m/s. The size of large drops is 2.0 mm and their terminal velocity is 6.49 m/s.&lt;/p&gt;&#xA;&lt;p&gt;For &lt;strong&gt;Moderate Stratiform Rain&lt;/strong&gt;, light rain had drops 1.0 mm in size and a terminal velocity of 4.03 m/s. The size of large drops is 2.6 mm and their terminal velocity is 7.57 m/s.&lt;/p&gt;&#xA;&lt;p&gt;For &lt;strong&gt;Heavy Thundeshowers&lt;/strong&gt;, light rain had drops 1.2 mm in size and a terminal velocity of 4.64 m/s. The size of large drops is 4.0 mm and their terminal velocity is 8.83 m/s.&lt;/p&gt;&#xA;&lt;p&gt;When rain drops start to get to be larger than 4.5 mm in size they split in two, as illustrated by this diagram, which relates rain drop shape to its size. Below 1 mm in diameter, rain drops &amp;quot;are almost spherical&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/F9c6U.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/F9c6U.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-07-26T11:48:21.320" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22604" PostTypeId="2" ParentId="22600" CreationDate="2021-07-26T12:54:09.753" Score="3" Body="&lt;p&gt;Imagine the whole ball being separated into a handful of concentric shells, with the outermost shell being the crust with the surface, and the lower shells ever deeper, hotter, and ghastly regions of the internals of our planet.&lt;/p&gt;&#xA;&lt;p&gt;Now, just for the thought experiment, forget that each individual shell has &amp;quot;stuff&amp;quot; going on in itself, and just imagine it as a volume of whatever material (dirt, lava, etc.) there is.&lt;/p&gt;&#xA;&lt;p&gt;The outermost shell then is acted on by gravity and pulled inwards/down. But that's all that gravity does. It does not create pressure on its own, at all! The pressure only occurs because the next layer resists the previous layer - or Earth would implode (which, incidentally, is what actually does happen in a supernova).&lt;/p&gt;&#xA;&lt;p&gt;The principle is the same as if you heat water on the stove, in one of those pots with a screw-on lid. To create pressure, you need hot water, but you &lt;em&gt;also&lt;/em&gt; need the lid resisting the water vapors trying to &amp;quot;get out&amp;quot;. Remove either factor, and there is an open pot without any pressure.&lt;/p&gt;&#xA;&lt;p&gt;Back to Earth: this phenomenon continues. As you noticed, the effect of gravity on each individual shell gets less and less (the shells weigh less, the farther you go down, even if you size them such that they have the same mass as the previous ones). But the downward force from all the upper layers is still there just fine - at this point, gravity has already done its work and it does not matter &lt;em&gt;why&lt;/em&gt; the upper shells press down. All the matter there is already compressed as much as possible under the circumstances (of course not compressed as much as physically possible - our planet is much too small/light for that), so the forces from above are transmitted further down.&lt;/p&gt;&#xA;&lt;p&gt;Obviously, in reality there aren't any well-defined shells and the effect on gravity works on all individual atoms making up Earth, but the principle remains. All that is on top presses down, and thus there is pressure at the very center, albeit there is no or very little gravity down there.&lt;/p&gt;&#xA;" OwnerUserId="23070" LastEditorUserId="502" LastEditDate="2021-08-13T16:51:40.497" LastActivityDate="2021-08-13T16:51:40.497" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22606" PostTypeId="1" AcceptedAnswerId="22610" CreationDate="2021-07-26T14:01:47.073" Score="2" ViewCount="468" Body="&lt;h2 id=&quot;disclaimer&quot;&gt;Disclaimer&lt;/h2&gt;&#xA;&lt;p&gt;I've read &lt;a href=&quot;https://earthscience.stackexchange.com/questions/22415/if-we-send-ocean-waters-into-glacier-of-north-pole-south-pole-to-reduce-sea-leve&quot;&gt;this question&lt;/a&gt; already on sending water to the north pole, south pole and glaciers, and I thought I'd give it my own take and see how technically possible it could be.&lt;/p&gt;&#xA;&lt;h2 id=&quot;question&quot;&gt;Question&lt;/h2&gt;&#xA;&lt;p&gt;As previously established by [a majority of the scientific community], sea levels and global temperatures continue to rise as result of climate change (and humans causing climate change.) Rising sea levels are not good news for islands or low-lying ground, and as such that is the basis for this question.&lt;/p&gt;&#xA;&lt;p&gt;Let's say an extravagant inventor came up with a device/system that would perform the following actions:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Energy is collected from wind and solar panels in the North and&#xA;South poles.&lt;/li&gt;&#xA;&lt;li&gt;The electrical energy is used to pump sea water, filtered of the salt &amp;amp; other impurities, into small containers.&lt;/li&gt;&#xA;&lt;li&gt;The purified/filtered water is frozen in these containers with nitrogen.&lt;/li&gt;&#xA;&lt;li&gt;The frozen water is moved (possibly via robots/remote controlled&#xA;vehicles), stacked and stored on land, which over time would build&#xA;up the amount of water concentrated in the poles.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Apart from the cost factor (which would be &lt;em&gt;significant&lt;/em&gt;), how practical could this solution be in reducing sea levels/the temperature increase from climate change?&lt;/p&gt;&#xA;" OwnerDisplayName="user23072" LastActivityDate="2021-07-27T20:20:55.187" Title="Would freezing the ocean and storing the ice in the poles reduce effects of climate change or sea level?" Tags="|climate-change|sea-level|sea-ice|poles|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22607" PostTypeId="2" ParentId="22600" CreationDate="2021-07-26T14:16:15.993" Score="9" Body="&lt;p&gt;Pressure at the center of the earth is non-zero. You're correct that there's no gravitational force at the center of the earth, but that doesn't mean pressure is zero - the pressure comes from the many miles of rock sitting above the center of the earth.&lt;/p&gt;&#xA;&lt;p&gt;As an analogy, think of a balloon. The pressure inside is higher than ambient because the elastic skin of the balloon pulls in everywhere on the surface. Pressure at the center of the balloon is higher, despite the fact that &lt;em&gt;no force pulls inward on the center&lt;/em&gt; - the increased pressure comes from the outer shell of the balloon pulling inward. You can think of the earth in much the same way - even though there's no gravity acting at the center of the earth, any arbitrary &amp;quot;outer shell&amp;quot; experiences a gravitational force pulling down which contributes to the pressure below.&lt;/p&gt;&#xA;" OwnerUserId="4971" LastEditorUserId="4971" LastEditDate="2021-07-26T18:13:41.720" LastActivityDate="2021-07-26T18:13:41.720" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22609" PostTypeId="1" CreationDate="2021-07-26T14:46:14.143" Score="4" ViewCount="49" Body="&lt;p&gt;Imagine the Earth's axis of rotation were to precess in synch with the orbit of earth around the sun so the north pole always pointed towards the sun (same current axial tilt of about 23 degrees).  Inside the arctic circle it would always be day light.  Between the tropics and the arctic circle daylight hours would vary from slightly greater than 12 hours to much greater than 12 hours.&lt;/p&gt;&#xA;&lt;p&gt;This would obviously wreak havoc on jet streams and thermohaline currents, but eventually things would stabilize and you'd reach a max temperature (ish) relative to latitude.&lt;/p&gt;&#xA;&lt;p&gt;How scorchingly hot would the high arctic get and what would more temperate zones like 35 and 45 degrees latitude max out at for daily highs?&lt;/p&gt;&#xA;" OwnerUserId="23074" LastActivityDate="2021-07-26T14:46:14.143" Title="How hot would days get if it were always the solstice in the northern hemisphere?" Tags="|geophysics|climate|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22610" PostTypeId="2" ParentId="22606" CreationDate="2021-07-26T15:19:49.820" Score="4" Body="&lt;p&gt;There are a couple of different questions in there -- one is whether this would help with sea level rise, the other whether this would help with temperature increase. (The second part is easy to answer; it wouldn't help with temperatures at all -- nominally, freezing would involve moving heat from the water to somewhere else in the climate system.)&lt;/p&gt;&#xA;&lt;p&gt;(Notably there is no land at the North Pole. You'd want Greenland.)&lt;/p&gt;&#xA;&lt;p&gt;I'm pretty sure we've dealt with this issue in parts in other questions, such as the practicality of shoring up ice sheets, pumping water into the center of the Antarctic, or pumping water into the desert interior of another continent. You're basically talking about not just reversing the equivalent of one of the largest rivers in the world (the Congo River being roughly comparable with current rates of melt), but also freezing all of that water and conveying it over land.&lt;/p&gt;&#xA;&lt;p&gt;In reality, you're not going to get much reliable wind and solar from polar installations, where the sun is at a poor angle and the winds can be destructive (though you'll get some, see Princess Elisabeth station &lt;a href=&quot;http://www.antarcticstation.org/station/renewable_energies&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.antarcticstation.org/station/renewable_energies&lt;/a&gt;). Even if you have a magical source of energy to power this freezing and transporting process so that you're not burning fossil fuels, you're also talking about building the world's largest infrastructure projects in the world's most inhospitable environments and maintaining them for the hundreds of years it will take for CO&lt;sub&gt;2&lt;/sub&gt; levels to decline to pre-industrial levels.&lt;/p&gt;&#xA;&lt;p&gt;Also, to the degree this magically solves or reduces any problems, it will encourage some nations (such as Russia, which benefits from a warming world) to continue burning fossil fuels.&lt;/p&gt;&#xA;&lt;p&gt;In short, the energy, engineering, infrastructure, and political will it would take to try to pull this off would be better spent on reducing carbon emissions and/or extracting carbon dioxide from the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastEditorUserId="7314" LastEditDate="2021-07-27T20:20:55.187" LastActivityDate="2021-07-27T20:20:55.187" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22611" PostTypeId="2" ParentId="22602" CreationDate="2021-07-26T17:42:20.493" Score="3" Body="&lt;p&gt;My first observation upon looking at the picture was that Typhoon In-fa (the southernmost one in the picture) nearly stalled prior to making the right angled turns in its path. There is a clustering of very closely spaced location markers for the dates 19 and 20 July, prior to the first 90 degree turn and then again for the dates 22 to 24 July at the time of the second 90 degree turn.&lt;/p&gt;&#xA;&lt;p&gt;The the first paragraph of the Wikipedia article you refer to states,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;... on July 17, being assigned the name In-fa by the Japan Meteorological Agency. Located in a week steering environment, the system &lt;strong&gt;struggled to organize under dry air and moderate wind shear before organizing further&lt;/strong&gt;. It continued to move mostly westward, strengthening into a typhoon and deepening quickly. The storm struggled to organize itself significantly due to continuous dry air intrusions.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The emphasis is mine.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_cyclone&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tropical cyclones&lt;/a&gt; (typhoons, hurricanes) thrive when surface sea temperatures are very warm and the air is humid. Encountering dry air will disrupt a typhoon, which is what happened with In-fa.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;... The large size of In-fa, with the continuous dry air entrainment, together restrained the system's rapid development over the warm waters of the Philippine Sea; however, as the storm continued its trajectory towards the Ryukyu Islands, the curved banding of the system further consolidated ...&lt;/p&gt;&#xA;&lt;p&gt;... At the same time, the system began to take a northwest track before moving west-northwestwards under a &lt;a href=&quot;https://en.wikipedia.org/wiki/Horse_latitudes&quot; rel=&quot;nofollow noreferrer&quot;&gt;subtropical ridge&lt;/a&gt; over Japan by the early hours of July 19. ...&lt;/p&gt;&#xA;&lt;p&gt;... The system, decelerates again as it started to impact the Ryukyu's, with In-fa's convection or thunderstorms deepening and an eye further appearing. ...&lt;/p&gt;&#xA;&lt;p&gt;As it passed south of Daito Islands, a 35 nautical mile (65 km; 40 mi) eye was further evident on satellite imageries, which later shrinked; however, In-fa remained a high-end Category 1 system as it started to move westwards and later, a west-southwest track. ...&lt;/p&gt;&#xA;&lt;p&gt;... on July 21 with winds of 175 km/h (110 mph); this made the system's peak intensity according to the JTWC's estimates.&lt;/p&gt;&#xA;&lt;p&gt;... another satellite imagery revealed an eyewall that was disrupted due to continuous dry air intrusions while moving westwards. Later, as it shifted its motion west-southwestwards, In-fa's eye became ragged due to another pack of dry air. Furthermore, dry northerlies suppressed the core of the system as it dived southwards. ...&lt;/p&gt;&#xA;&lt;p&gt;... In-fa started an eyewall replacement cycle while its northern quadrant started to weaken as it changed its motion yet again to the south-southwest. In addition, the system is being steered by the southern periphery of a high-amplitude ridge over the Sea of Japan. Six hours later, the typhoon started to weaken with its eye expanding and weakening banding on the system while tracking westward and further, northwestward at an slow motion rate. &lt;strong&gt;Its steering movements were caused by a subtropical ridge to the north and further, another one over the east coast of North Korea.&lt;/strong&gt; As it continued to approach the Ryukyus while traveling from the northwest, In-fa further weakened to a high-level Category 1 system due to continuous up welling, its suppressed outflow and slowly cooling sea surface temperatures.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In summary, the formation of the typhoon was periodically interrupted by the entrainment of dry air. This coupled with the subtropical ridge initially over Japan then to its north and another to the east of North Korea.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-07-26T17:42:20.493" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22612" PostTypeId="1" AcceptedAnswerId="22618" CreationDate="2021-07-26T18:44:24.497" Score="3" ViewCount="281" Body="&lt;p&gt;I have two datasets, each with two differing resolutions. The first dataset is a coarser resolution data set that has 0.5 x 0.625 degree resolution and contains values of MERRA-2 boundary layer thickness. The second, finer resolution dataset has 0.1 x 0.1 degree resolution and contains values of IMERG rainfall rate. I want to find the boundary layer thickness at every point where the rainfall rate exceeds 10 mm/hr. Since the MERRA-2 boundary layer thickness dataset is coarser, I figured that I could create a grid from the latitude and longitude values in the MERRA-2 dataset and check if the IMERG data points lie within any of the MERRA-2 grid boxes. I'm having trouble figuring out where to start with this, and any help is greatly appreciated.&lt;/p&gt;&#xA;&lt;p&gt;Here is the formatting of the latitude and longitude for each dataset:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;MERRA-2 Latitude: [[1.3500000e+01  1.3500000e+01  1.3500000e+01  1.3500000e+01]&#xA;MERRA-2 Longitude: [[-51.875 -51.25  -50.625 -50.    -49.375 -48.75  -48.125 -47.5   -46.875]&#xA;IMERG Latitude: [-0.05  0.05  0.15  0.25  0.35  0.45  0.55  0.65  0.75  0.85  0.95  1.05]&#xA;IMERG Longitude: [-49.95 -49.85 -49.75 -49.65 -49.55 -49.45 -49.35 -49.25 -49.15 -49.05]&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;EDIT: I have created a regridded dataset from Nemesi's first methodology (cdo remapcon), and they can be found below. The top image is the regridded data, and the bottom is the original data. Although the number of points in the newly regridded dataset increased from 59,040 to 5,475,600, the image seems to have lower resolution than the original image. The IMERG data also seems to have higher resolution even though both datasets have the same amount of points. Is this due to an error with the data formatting?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EyrtK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EyrtK.png&quot; alt=&quot;Original dataset&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/TVD6r.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TVD6r.png&quot; alt=&quot;Newly regridded dataset&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20707" LastEditorUserId="20707" LastEditDate="2021-07-28T19:02:11.110" LastActivityDate="2021-07-28T19:02:11.110" Title="Determining if a fine resolution lat/lon point lies in a coarse resolution lat/lon grid box?" Tags="|meteorology|python|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22613" PostTypeId="1" AcceptedAnswerId="22619" CreationDate="2021-07-26T20:11:59.063" Score="2" ViewCount="58" Body="&lt;p&gt;I am unsure if this is the correct place to ask such a question I will give it a go.&lt;/p&gt;&#xA;&lt;p&gt;So, the lab I work in is building a &amp;quot;drone park&amp;quot; to conduct robotics and controls experiments in. This drone park will be a netted enclosure where we will be flying drones around in and for analysis of these experiments I think it will be very useful to know what kinds of winds these robots experienced during flight. So with that, what would be a suitable setup and/or system we could purchase to adequately record this information in such away that we can say, &amp;quot;this drone experienced wind of &lt;code&gt;this speed&lt;/code&gt; with a direction of &lt;code&gt;theta degrees&lt;/code&gt;&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;I am a robotics/controls guy and do not have too much practical knowledge of measuring wind. For example, can I get away with one sensor in the center measuring direction and speed and say that is relatively uniform over the whole drone park, or will I need a network of sensors? Should I use 3d sensors (I think so).&lt;/p&gt;&#xA;&lt;p&gt;Overall, I would like a recommendation of what sensor(s) to get, how many, and what configuration.&lt;/p&gt;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;&lt;p&gt;EDIT: Whatever the system is, I need to access raw data through a live feed.&lt;/p&gt;&#xA;&lt;p&gt;EDIT: I'd like to also avoid placing this sensor on the drone as that is not the intended use for this.&lt;/p&gt;&#xA;" OwnerUserId="23080" LastEditorUserId="23080" LastEditDate="2021-07-26T20:18:35.270" LastActivityDate="2021-07-27T17:08:29.000" Title="Wind monitoring system for a specified region: How should this be done, and with what?" Tags="|meteorology|weather-forecasting|wind|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22614" PostTypeId="1" CreationDate="2021-07-27T03:27:08.453" Score="3" ViewCount="235" Body="&lt;p&gt;I'm trying to get a general idea of how Earth and other planets behave over time for a project. While I can find plenty of good data about how much radiative heating there was, I can't find anything on primordial heat.&lt;/p&gt;&#xA;&lt;p&gt;What kind of relationship does internal heat and time have?&lt;/p&gt;&#xA;&lt;p&gt;cheers.&lt;/p&gt;&#xA;" OwnerUserId="23082" LastActivityDate="2021-07-29T18:08:44.040" Title="How much of Earth's internal heat comes from primordial heating and how has it changed since Earth's formation?" Tags="|temperature|geothermal-heat|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22615" PostTypeId="2" ParentId="20063" CreationDate="2021-07-27T04:50:52.380" Score="1" Body="&lt;p&gt;Depends what you're interested in, but if you take the atmosphere as being the breathable atmosphere its only about 6km thick.&lt;/p&gt;&#xA;&lt;p&gt;This is important because when people think about air pollution if you have a visual in your mind that the pollutants we put into the air all being concentrated into that thin layer then you start to think differently. So if the earth was a basketball, the breathable atmosphere on which we depend is about a tenth of a millimetre thick.&lt;/p&gt;&#xA;" OwnerUserId="23084" LastActivityDate="2021-07-27T04:50:52.380" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22616" PostTypeId="2" ParentId="19046" CreationDate="2021-07-27T06:03:07.880" Score="5" Body="&lt;p&gt;A good place to start would be with &lt;a href=&quot;https://www.oxfordreference.com/view/10.1093/oi/authority.20110803095829880&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fortin barometers&lt;/a&gt;. They were &amp;quot;&lt;a href=&quot;https://physicsmuseum.uq.edu.au/fortin-mercury-barometer&quot; rel=&quot;nofollow noreferrer&quot;&gt;commonly used at meteorological stations to measure atmospheric pressure&lt;/a&gt;&amp;quot;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The advantages of this type of barometer are its portability (inverted), and that it permits the inspection of both free surfaces of mercury whose difference in level have to be measured. The major disadvantage is the cistern and the mercury it contains require frequent cleaning to maintain the instrument's accuracy.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A portable mercury barometer that was invented in 1800 by the French instrument maker Jean Nicholas Fortin (1750–1831). In other mercury barometers air pressure is calculated from the distance between the level of the mercury in the reservoir and in the tube. In the Fortin barometer the bottom of the reservoir is flexible (originally it was made from leather) and can be raised or lowered by means of a screw, allowing the surface of the mercury to be adjusted to a predetermined level. A vernier scale on the side of the barometer tube is then lowered until its base touches the top of the mercury in the reservoir and a reading is taken from the fixed scale marked on the tube. Before traveling, the base of the reservoir is raised using the adjusting screw until both reservoir and tube are filled with mercury. The Fortin barometer makes no correction for changes in temperature, which affect the volume of mercury, or for capillarity, which introduces inaccuracies. The instrument is nevertheless sufficiently accurate for most purposes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Another type of mercury based barometer is the &lt;a href=&quot;https://storyfeed.me/fortin-barometer-38/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kew Pattern&lt;/a&gt;. Unlike a Fortin barometer the mercury system is fixed in position. To compensate for the effect this has on pressure readings the scale used by Kew Pattern barometers is &lt;a href=&quot;http://gluedideas.com/Encyclopedia-Britannica-Volume-3-Baltimore-Braila/Barometer.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;contracted&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The diagram below illustrates the features of a Fortin barometer.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oiu6W.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oiu6W.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Immediately prior to taking a pressure reading, the air temperature needs to be measured so the reading from the barometer can be corrected. It also needs to be measured as soon as possible, prior to reading the pressure so the barometer is not affect by the body temperature of the person taking the measurement.&lt;/p&gt;&#xA;&lt;p&gt;The height of the mercury cistern in the barometer is then adjusted to just touch the ivory pointer.The &lt;em&gt;floating&lt;/em&gt; vernier scale is then lowered to just touch the meniscus of the mercury in the tube.&lt;/p&gt;&#xA;&lt;p&gt;The scale on the side of the barometer gives the main part of the pressure reading and the vernier gives the decimal fraction.&lt;/p&gt;&#xA;&lt;p&gt;Referring back to the question, the barometer doesn't float, the vernier scale is the item that &amp;quot;floats&amp;quot; by being adjustable.&lt;/p&gt;&#xA;&lt;p&gt;The picture below illustrates the &lt;a href=&quot;https://duckduckgo.com/?t=ffab&amp;amp;q=fortin%20barometer&amp;amp;atb=v246-1&amp;amp;iax=images&amp;amp;ia=images&amp;amp;iai=http%3A%2F%2Fwww.russell-scientific.co.uk%2Fekmps%2Fshops%2Frussellsci%2Fimages%2Ff52-fortin-barometer-%5B2%5D-226-p.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;position of the vernier scale&lt;/a&gt; when taking a reading from a Fortin barometer.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cMlFE.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cMlFE.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-07-27T09:18:42.707" LastActivityDate="2021-07-27T09:18:42.707" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22617" PostTypeId="2" ParentId="22600" CreationDate="2021-07-27T08:02:23.803" Score="13" Body="&lt;p&gt;The previous answers do a fine job already. But I'll try to add a simple thought experiment. Imagine three objects floating in space, clumping together by gravity:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;###   ###&#xA;#A#|c|#B#&#xA;###   ###&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Mass A, the negligible mass c and mass B, equal to A. The center is attracted to A and B and their gravity cancels out. However, A presses against c, because it is attracted by B, and B presses against c from the opposite direction. So of course, c will feel the pressure from both A and B, even though it feels no gravity.&lt;/p&gt;&#xA;" OwnerUserId="23087" LastEditorUserId="502" LastEditDate="2021-08-13T16:51:45.243" LastActivityDate="2021-08-13T16:51:45.243" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22618" PostTypeId="2" ParentId="22612" CreationDate="2021-07-27T08:35:44.273" Score="5" Body="&lt;p&gt;Note: I'm assuming that the original data are provided in NetCDF format.&lt;/p&gt;&#xA;&lt;p&gt;There are two (OK, there are more, but I'll focus on these two) relatively quick ways to deal with this issue. Which one to prefer is very much depending on your preference and ability to use the different tools involved.&lt;/p&gt;&#xA;&lt;p&gt;The fastest approach that comes to my mind is using the Climate Data Operator (CDO): you can find a detailed documentation &lt;a href=&quot;https://code.mpimet.mpg.de/projects/cdo/embedded/cdo.pdf&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; and an overview &lt;a href=&quot;https://code.mpimet.mpg.de/projects/cdo/wiki/Tutorial&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The approach should be to get the grid description from the highest resolution file:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;cdo -griddes imerg.nc&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Then, take the description of the grid and put it in a &lt;code&gt;.txt&lt;/code&gt; file and remap the coarser resolution file to match this grid. In this case, you may want to use a conservative remapping methodology to maintain the original values unaltered.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;cdo remapcon,imerggrid.txt merra_coarse.nc merra_imerggrid.nc&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;In this way you would have the MERRA-2 data in a resolution matching your IMERG grid.&lt;/p&gt;&#xA;&lt;p&gt;The second approach uses &lt;code&gt;R&lt;/code&gt;.&#xA;Steps (very quickly):&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;load the two NetCDF files as raster;&lt;/li&gt;&#xA;&lt;li&gt;make a raster to point transformation (or just extract the coordinates and transform them in a Point Spatial object) of the imerg raster (in this way you would obtain the centroids of the imerg cells);&lt;/li&gt;&#xA;&lt;li&gt;extract the data from the merra object overlaying the imerg points.&#xA;All these passages are well documented in &lt;a href=&quot;https://stackoverflow.com/&quot;&gt;stackoverflow&lt;/a&gt; or &lt;a href=&quot;https://gis.stackexchange.com/&quot;&gt;gis.stackexchange&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;This last methodology, however, may result in a very slow process in case of large datasets.&lt;/p&gt;&#xA;" OwnerUserId="8087" LastActivityDate="2021-07-27T08:35:44.273" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="22619" PostTypeId="2" ParentId="22613" CreationDate="2021-07-27T16:00:09.533" Score="2" Body="&lt;p&gt;The wind varies with height (speed and direction) so the measurement will depend on the flight height of the drones.&lt;/p&gt;&#xA;&lt;p&gt;It is best to have a &lt;a href=&quot;https://en.wikipedia.org/wiki/Lidar&quot; rel=&quot;nofollow noreferrer&quot;&gt;lidar&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Sodar&quot; rel=&quot;nofollow noreferrer&quot;&gt;sodar&lt;/a&gt; equipment for 3D wind measurement, but they are expensive (they can measure more than 150 m).&lt;/p&gt;&#xA;&lt;p&gt;Another alternative is to install a meteorological tower with wind measurements at different heights. Obviously, the height of the sensors will depend on the flight height and the number of towers will depend on the terrain type of the &amp;quot;drone park&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;On flat terrain, without hills or structures, the wind (horizontally) can be considered uniform.&lt;/p&gt;&#xA;" OwnerUserId="17863" LastEditorUserId="2470" LastEditDate="2021-07-27T17:08:29.000" LastActivityDate="2021-07-27T17:08:29.000" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22620" PostTypeId="1" CreationDate="2021-07-28T07:09:03.213" Score="5" ViewCount="112" Body="&lt;p&gt;I hope that my question fits in this forum.&lt;br /&gt;&#xA;I am looking for empirical literature dedicated to pollution in the forest.&#xA;So far, I have only found psychological literature that tries to find out what means can be used to make people litter less in the forest.&lt;br /&gt;&#xA;But I am looking for studies that try to find out how much garbage is in the forest, how this garbage is distributed and what this garbage is made of (plastic, metal, paper, ...).&#xA;Unfortunately, so far I have not found anything about this. I hope that someone here can help me further.&lt;/p&gt;&#xA;&lt;p&gt;Many thanks in advance!&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gCbf6.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gCbf6.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="23107" LastActivityDate="2021-10-13T05:17:49.930" Title="Looking for study on the pollution of the forest" Tags="|pollution|forest|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22621" PostTypeId="2" ParentId="22591" CreationDate="2021-07-28T07:24:20.653" Score="3" Body="&lt;p&gt;Phanerozoic CO&lt;sub&gt;2&lt;/sub&gt; atmospheric levels:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BvgmP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BvgmP.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Biosphere has been consuming CO&lt;sub&gt;2&lt;/sub&gt; and storing it in the lithosphere since the Cambrian explosion.&lt;/p&gt;&#xA;&lt;p&gt;The cyclic pattern is related with the tectonic cycles, named the &lt;a href=&quot;https://en.wikipedia.org/wiki/Wilson_Cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wilson Cycle&lt;/a&gt;, wich has formed two super continents during Phanerozoic period: Rodinia and Pangea.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/E3KEz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/E3KEz.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;When a super continent breaks, a new ocean is formed and after Cambrian CO&lt;sub&gt;2&lt;/sub&gt; begins to get stored in the carbonate platforms close to newly formed coastlines, reducing the levels in the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;When the ocean formed in a Wilson Cycle is old enough, oceanic crust begins to subduct the continents and after Cambrian part of this carbon returns to the atmosphere from &lt;a href=&quot;https://en.wikipedia.org/wiki/Calc-alkaline_magma_series&quot; rel=&quot;nofollow noreferrer&quot;&gt;calc-alkaline magmas&lt;/a&gt; of volcanic arcs. This is what is starting to happen in the Atlantic Ocean.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Currently, the Atlantic has three isolated subduction zones: the&#xA;Lesser Antilles in the Caribbean, the Scotia Arc in the South&#xA;Atlantic, and the Gibraltar Arc in the Mediterranean.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xxIVY.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xxIVY.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;source: &lt;a href=&quot;https://www.earthmagazine.org/article/new-subduction-zone-may-close-atlantic-ocean#:%7E:text=Currently%2C%20the%20Atlantic%20has%20three%20isolated%20subduction%20zones%3A,with%20the%20ongoing%20subduction%20of%20the%20Gibraltar%20Arc.&quot; rel=&quot;nofollow noreferrer&quot;&gt;earthmagazine.org&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Part of the CO&lt;sub&gt;2&lt;/sub&gt; gets stored in the Continental Crust, staying in the lithosphere reservoir in the form of CaCO&lt;sub&gt;3&lt;/sub&gt;. So the balance of Wilson Cycle since the Cambrian is a reduction of CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere (shown in the first graph), and an increase of Continental Crust. The second consequence applies for the hole Earth History where the Wilson Cycle has been operating.&lt;/p&gt;&#xA;&lt;p&gt;A teacher told us in University the Pacific ring is more powerfull than Atlantic dorsal, and Atlantic Ocean is going to disappear. If that is true, in the following millions of years, part of the CO&lt;sub&gt;2&lt;/sub&gt; stored in the Atlantic Ocean will return to the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;So answering your question, the Earth would not run out of CO&lt;sub&gt;2&lt;/sub&gt; in the next million years with no human intervention. Some CO&lt;sub&gt;2&lt;/sub&gt; stored in the Atlantic Ocean is going to be released to the atmosphere. Maybe in the next Wilson Cycle when the Atlantic Ocean closes forming a new supercontinent and breaking again forming a new ocean, but it is a nosense to talk about climate in said 100my as human technology for sure will modelate climate in the future.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Apart from volcanism are there any processes that return carbon captured in fossil fuels and limestone to the atmosphere?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Apart from humans burning fossil fuels and volcanism, CaCO3 starts to dissolve in the oceans at certain profundity/pressure. The level when CaCO&lt;sub&gt;3&lt;/sub&gt; start to dissolve is known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonate_compensation_depth#:%7E:text=Carbonate%20compensation%20depth%20%28%20CCD%29%20is%20the%20depth,sediments%20on%20the%20sea%20floor%20below%20this%20depth.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Carbonate compensation depth (CCD)&lt;/a&gt;. The ocean is in equillibrium with the atmosphere because of &lt;a href=&quot;https://en.wikipedia.org/wiki/Henry%27s_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Henry's law&lt;/a&gt; so that affects atmospheric CO&lt;sub&gt;2&lt;/sub&gt; levels.&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-08-07T16:12:05.857" LastActivityDate="2021-08-07T16:12:05.857" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22622" PostTypeId="2" ParentId="9588" CreationDate="2021-07-28T09:27:22.407" Score="1" Body="&lt;p&gt;A rather late answer on this question, but here goes: The idea that &amp;quot;global temperatures cause the increase of CO2.&amp;quot; is fairly easily refuted.  The usual line of reasoning is that the solubility of CO2 in water decreases as temperature increases, so the rise in global temperature implies that the oceans will have released some of the dissolved CO2 that it contains.  The premise is correct, but the conclusion is a non sequitur as it ignores the fact that the solubility of CO2 in water also depends on the difference in the concentrations of CO2 between the surface ocean and the atmosphere.  As we have released CO2 from fossil fuels into the atmosphere, the partial pressure of CO2 in the atmosphere has risen, and so the oceans have been taking up more CO2, not less.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;How do we know this is true? .  The argument is easily refuted by the&#xA;observation that the rate at which atmospheric CO2 levels are rising&#xA;is less than the rate at which we are releasing CO2 into the&#xA;atmosphere from fossil fuel use, which implies that the natural&#xA;environment must be a net carbon sink, taking in more carbon each year&#xA;than it emits.&lt;/p&gt;&#xA;&lt;p&gt;More formally, let Ea represent annual carbon emissions from&#xA;anthropogenic sources (fossil fuel use and land use change), En&#xA;represent the carbon emissions from all natural sources (the oceans,&#xA;soil respiration, volcanos etc.) and Un represent the uptake of carbon&#xA;by all natural carbon sinks (oceans, photosynthesis, etc.), Ua would&#xA;be the uptake of carbon due to anthropogenic activities, but this is&#xA;essentially zero, so we can safely exclude it from the analysis.  Then&#xA;assuming that the carbon cycle obeys the principle of conservation of&#xA;mass (any carbon emitted into the atmosphere that is not taken up by&#xA;natural sinks remains in the atmosphere), the annual change in&#xA;atmospheric CO2 is given by:&lt;/p&gt;&#xA;&lt;p&gt;C' = Ea + En - Un&lt;/p&gt;&#xA;&lt;p&gt;This can be rearranged to give an estimate of the difference between&#xA;annual emissions from all natural sources and annual natural uptake by&#xA;all natural sinks.&lt;/p&gt;&#xA;&lt;p&gt;En - Un = C' - Ea&lt;/p&gt;&#xA;&lt;p&gt;We have accurate, reliable data for the growth of atmospheric CO2 and&#xA;for anthropogenic emissions (for details, see Cawley, 2011). Both of&#xA;these are displayed below, along with an estimate of the net natural&#xA;carbon flux En - Un.  The fact that the net natural flux is negative&#xA;clearly shows that natural uptake has exceeded natural emissions every&#xA;year for the last fifty years at least, and hence has been opposing,&#xA;rather than causing the observed rise in atmospheric CO2.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/fZfsT.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.skepticalscience.com/print.php?n=1259&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Some time back, I wrote a journal paper refuting a related climate myth, which outlines some of the evidence that the rise in atmospheric CO2 is anthropogenic, and is not a natural phenomenon.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://pubs.acs.org/doi/abs/10.1021/ef200914u&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gavin C. Cawley, &amp;quot;On the Atmospheric Residence Time of Anthropogenically Sourced Carbon Dioxide&amp;quot;, Energy &amp;amp; Fuels, volume 25, issue 11, pages 5503–5513, 2011.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This answer is adapted from my &lt;a href=&quot;https://skeptics.stackexchange.com/questions/3435/does-co%E2%82%82-cause-global-warming/17707#17707&quot;&gt;answer&lt;/a&gt; to a similar question on the Skeptics SE.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;The general consensus is that CO2 increase causes temperature increase, why is the reverse situation not studied (if it is I could not find any studies).&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;There are actually plenty of studies of this, it is just that the issues were largely resolved over fifty years ago.  The main mechanism is the temperature dependent solubility of CO2 in the oceans, there is an excellent textbook on this by &lt;a href=&quot;https://www.elsevier.com/books/co2-in-seawater-equilibrium-kinetics-isotopes/zeebe/978-0-444-50946-8?countrycode=GB&amp;amp;format=print&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zeebe and Wolf-Gladrow&lt;/a&gt;.  There is also an effect of temperature on the biosphere, which is a bit more difficult to pin down, but see the references in the relevant section of the IPCC report.  The research is there, but we have known for a &lt;em&gt;&lt;strong&gt;long&lt;/strong&gt;&lt;/em&gt; time that the rise in CO2 is not the result of natural processes, so there will be no papers explicitly making this claim (at least from people who understand the basics) because there has been no new evidence to support it.&lt;/p&gt;&#xA;" OwnerUserId="624" LastActivityDate="2021-07-28T09:27:22.407" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22623" PostTypeId="2" ParentId="22614" CreationDate="2021-07-28T10:20:34.217" Score="1" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/William_Thomson,_1st_Baron_Kelvin#Age_of_the_Earth:_geology&quot; rel=&quot;nofollow noreferrer&quot;&gt;William Thompson, the first baron Kelvin&lt;/a&gt; worked out that the Earth was around 20 to 400 million years old, based on the rate of cooling from an assumed molten state.  This would imply that the Earth's primordial heat would already be essentially lost, so you could argue the answer is zero (assuming Kelvin's calculation remains reasonable).  However once energy is &amp;quot;thermalised&amp;quot; it loses any memory of where it is from, which makes that answer questionable.&lt;/p&gt;&#xA;&lt;p&gt;[I assume that by &amp;quot;radiative heating&amp;quot; you mean heating from radioctive decay in the mantle, rather than radiative heating of the surface by the sun.  There is also the Kelvin-Helmholtz heating from the iron sinking to form the core, but presumably that is finished now?]&lt;/p&gt;&#xA;" OwnerUserId="624" LastEditorUserId="2470" LastEditDate="2021-07-28T16:01:35.553" LastActivityDate="2021-07-28T16:01:35.553" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22628" PostTypeId="2" ParentId="22614" CreationDate="2021-07-29T18:08:44.040" Score="2" Body="&lt;p&gt;William Thomson's calculation is a poor first order approximation: take a molten blob of earth and calculate how long it takes too cool to near zero K. What Thomson couldn't know, for one thing, is how high initial temperatures got during the initial accretionary phase of earth's formation. Another thing that Thomson couldn't know in the mid 19th century is that the mantle is an excellent insulator, preventing much of that primordial heat from escaping.&lt;/p&gt;&#xA;&lt;p&gt;Despite uncertainties in composition and masses of specific chemistries of the deep earth, modern diamond anvil work has refined thermal conductivity values of earth materials at high temperatures and pressures. According to Quentin Williams of UC Santa Cruz, who, among many others, has done a lot of work constraining heat flow values in earth materials at depth:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.scientificamerican.com/article/why-is-the-earths-core-so/&quot; rel=&quot;nofollow noreferrer&quot;&gt;It takes a rather long time for heat to move out of the earth. This occurs through both &amp;quot;convective&amp;quot; transport of heat within the earth's liquid outer core and solid mantle and slower &amp;quot;conductive&amp;quot; transport of heat through nonconvecting boundary layers, such as the earth's plates at the surface. As a result, much of the planet's primordial heat, from when the earth first accreted and developed its core, has been retained.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You can find and read more of his work &lt;a href=&quot;https://eps.ucsc.edu/faculty/Profiles/fac-only.php?uid=qwilliam&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2021-07-29T18:08:44.040" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22630" PostTypeId="1" CreationDate="2021-07-30T00:15:42.863" Score="4" ViewCount="42" Body="&lt;p&gt;I am searching for previous work that has determined the electrical conductivity range for &lt;a href=&quot;https://en.wikipedia.org/wiki/Komatiite&quot; rel=&quot;nofollow noreferrer&quot;&gt;komatiites&lt;/a&gt; at the surface. Does anyone have some values or references?&lt;/p&gt;&#xA;" OwnerUserId="23131" LastEditorUserId="6031" LastEditDate="2021-07-30T00:30:16.660" LastActivityDate="2021-07-30T00:30:16.660" Title="What is the electrical conductivity of a liquid Komatiite?" Tags="|geophysics|geochemistry|volcanology|petrology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22631" PostTypeId="1" CreationDate="2021-07-30T12:51:40.213" Score="3" ViewCount="115" Body="&lt;p&gt;I am interested in weather predictions at 1-day, 1-week and 2-weeks, ideally with a 1-kilometer resolution in various regions around the globe. I am particularly interested in wind speed at 100m.&lt;/p&gt;&#xA;&lt;p&gt;I am extremely confused on how to choose the best data source for this. Some wild internet browsing presented me several NASA, ECMWF, ... forecasts that are available.&lt;/p&gt;&#xA;&lt;p&gt;Does anyone know a comprehensive list of all the (possibly free) datasets out there for this kind of problem?&lt;/p&gt;&#xA;" OwnerUserId="6001" LastEditorUserId="6001" LastEditDate="2021-08-01T22:03:11.273" LastActivityDate="2021-08-05T06:50:13.733" Title="weather forecast data: how to know what to choose" Tags="|weather-forecasting|open-data|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22632" PostTypeId="1" AcceptedAnswerId="22655" CreationDate="2021-07-30T15:52:05.887" Score="4" ViewCount="270" Body="&lt;p&gt;Did geologists determine the age of rocks and fossils before the advent of modern scientific dating methods such as &lt;a href=&quot;https://www.nature.com/scitable/knowledge/library/dating-rocks-and-fossils-using-geologic-methods-107924044/&quot; rel=&quot;nofollow noreferrer&quot;&gt;radiometric, electron spin resonance and thermoluminescence&lt;/a&gt;?&lt;/p&gt;&#xA;&lt;p&gt;If they did, does anyone know how they went about it?&lt;/p&gt;&#xA;" OwnerUserId="21585" LastEditorDisplayName="user20559" LastEditDate="2021-08-04T07:31:38.323" LastActivityDate="2021-08-05T21:46:23.563" Title="Did geologists determine the age of rocks and fossils before the advent of modern scientific dating methods?" Tags="|geology|paleontology|dating|history-of-science|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22633" PostTypeId="2" ParentId="22620" CreationDate="2021-07-31T06:11:04.760" Score="5" Body="&lt;p&gt;So far, I thought there won't be any studies on the overall scenario of waste disposals. After searching in depth, I have found studies on illegal waste dumping sites in Polish forests. Hope these will be helpful.&lt;/p&gt;&#xA;&lt;p&gt;Jakiel et al. (2018) assessed the spatiotemporal distribution of wastes in the Ojcow National Park, Poland. Number of dumping sites and volume of different types of wastes were determined through field observation. They categorized the dumping sites into very small, small, medium and large sized. It is a very comprehensive study.&lt;/p&gt;&#xA;&lt;p&gt;Another study by Zablocki et al. (2011) identified forests and natural depressions as the most common places for illegal waste dumping. Quantitative measurements of waste volumes can be found in this paper. Kolanowski and wisiniewki (2012) found total volume of 50 m&lt;sup&gt;3&lt;/sup&gt; garbage in the forest area of Ostrów Mazowiecka community.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Bibliography&lt;/strong&gt;:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Jakiel M., Bernatek-Jakiel, A., Gajda, A., Filiks, M. &amp;amp; Pufelska, M.(2018): Spatial and temporal distribution of illegal dumping sites in the nature protected area: the Ojców National Park, Poland, &lt;em&gt;Journal of Environmental Planning and Management&lt;/em&gt;, DOI: 10.1080/09640568.2017.1412941&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Kolanowski, B. &amp;amp; Wisiniewski, J. (2012). Assessment of the size and position of wild dumps in the White Forest in the municipality of Ostrow Mazowiecka classified as a&#xA;Natura 2000 [in Polish]. &lt;em&gt;Infrastruktura i Ekologia Terenów Wiejskich&lt;/em&gt;, 2 (I), 99. Accessed from: &lt;a href=&quot;https://agro.icm.edu.pl/agro/element/bwmeta1.element.agro-47c8e24c-3441-477d-9abc-261699a5b8b2&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://agro.icm.edu.pl/agro/element/bwmeta1.element.agro-47c8e24c-3441-477d-9abc-261699a5b8b2&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Zablocki, Z., Podlasinska, J. &amp;amp; Kruczek, I.(2011) Characteristics of illegal waste dumping sites located within area of Kobylanka community [in Polish]. &lt;em&gt;Folia Pomeranae Universitatis Technologiae Stetinensis, Agricultura, Alimentaria, Piscaria et Zootechnica&lt;/em&gt;. Vol.283 No.17 pp.41-50 &lt;a href=&quot;https://www.cabdirect.org/globalhealth/abstract/20123068877&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.cabdirect.org/globalhealth/abstract/20123068877&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Antczak, E., 2020. Regional Patterns in Dumping Sitesin Poland - Analysis in Context of the New &amp;quot;Sustainable&amp;quot; Waste Policy. &lt;em&gt;Polish Journal of Environmental Studies&lt;/em&gt;, 29(2), pp.1037-1049. DOI: 10.15244/pjoes/108484&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="22648" LastEditorUserId="22648" LastEditDate="2021-10-13T05:17:49.930" LastActivityDate="2021-10-13T05:17:49.930" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22634" PostTypeId="1" AcceptedAnswerId="22636" CreationDate="2021-07-31T08:35:53.043" Score="5" ViewCount="919" Body="&lt;p&gt;If perfumes and deodorants cause air pollution, does that mean they also heat the planet?&lt;/p&gt;&#xA;" OwnerDisplayName="user22619" LastEditorUserId="-1" LastEditDate="2021-07-31T19:46:23.417" LastActivityDate="2021-08-02T20:18:43.050" Title="Do perfumes and deodorants contribute to global warming?" Tags="|climate-change|climate|pollution|air|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22635" PostTypeId="2" ParentId="19439" CreationDate="2021-07-31T15:13:26.693" Score="5" Body="&lt;h2&gt;Yes it does happen, and we know when and why it happens.&lt;/h2&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Bad collection.&lt;/strong&gt; The most common reason is because of bad collection methods. Some times laypeople collect fossils without recording where or when they collected it, in those cases the fossil has no providence and is generally useless for scientific analysis. As long as you know what rock formation a fossil comes from you have a window of time it had to come from. This is by the way why some paleontologist absolutely detest private collectors, because so often it results in these useless fossils. While usually you can at least get a rough idea by comparing to similar fossils but sometimes the fossil is to badly damaged to even do that.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Bad luck&lt;/strong&gt;. Occasionally fossils are collected properly and because of unusual circumstances (say a museum being bombed in a war) collection data is lost and a fossil again becomes useless because it has no providence, this is one reason collection are encouraged to be recorded in detail in multiple locations. This happens often with fossils collected in the early days of paleontology when record keeping was often of lower quality.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Bad actors&lt;/strong&gt;. Sometimes a private collector engages in outright fraud, this most often happen in private collectors who want to make a fossil more salable. Often this evolves sticking the fossil in rock from a different formation or combining multiple different fossils into a single fraudulent piece. this is another reason many paleontologist dislike private collecting as it can encourage sellers to purposefully destroy a fossils providence. It is usually fairly easy for an experience paleontologist to spot such frauds but private buyers often cannot.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Bad Luck again.&lt;/strong&gt; There is one other circumstance, rarely you have reworked material, that is fossils that where exposed by erosion in the distance past then reburied, This is exceedingly rare, and always leaves its mark on the fossil, in that case we know the fossil is in the wrong place but may not know exactly where and thus when it comes from originally. Usually you can identify by finding similar fossils, but rarely the fossil so badly degraded identification is impossible.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://preparation.paleo.amnh.org/35/techniques-in-the-field&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://preparation.paleo.amnh.org/35/techniques-in-the-field&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/512371c&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/512371c&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2022-07-22T15:20:10.153" LastActivityDate="2022-07-22T15:20:10.153" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22636" PostTypeId="2" ParentId="22634" CreationDate="2021-07-31T15:15:39.520" Score="6" Body="&lt;p&gt;Maybe a little, but not much.  Personal care products that have a strong odor are typically associated with volatile organic compound (VOC) emissions.  VOCs are not really greenhouse gases, because they are reactive and very short-lived in the presence of sunlight.  However, VOCs do have a small indirect effect on global warming because they increase tropospheric ozone production in polluted atmospheres. Tropospheric ozone is a pretty important greenhouse gas, because it has a strong radiative forcing.  However, it is relatively short-lived and not a driver of anthropogenic climate change.&lt;/p&gt;&#xA;&lt;p&gt;Air pollution is generally studied in terms of human-health.  These air pollutants are often referred to as criteria (e.g. PM2.5, NO&lt;sub&gt;x&lt;/sub&gt;, tropospheric ozone, carbon monoxide, sulfur dioxide) and hazardous (e.g. ammonia, metals, VOCs) air pollutants.  While CAPs and HAPs do strongly influence atmospheric chemistry (which can influence greenhouse gases), air pollution usually involves chemicals that have short lifetimes (hours to days).  Conversely, strong greenhouse gases (e.g. CO&lt;sub&gt;2&lt;/sub&gt;, methane, HFCs) are long-lived and therefore can increase steadily over long periods of time (years).  This makes GHGs strong climate forcers, because climate is on the decadal scale.&#xA;Greenhouse gases are generally a distinctly separate list than CAPs and HAPs.  If you think about it, it makes sense that long-lived greenhouse gases generally do not directly cause adverse health effects.  If they did, we would be breathing &amp;quot;polluted&amp;quot; air our entire lives!  Health-based air pollution was regulated earlier than GHGs, so any pollutant that fits both criteria (e.g. ozone) would already be regulated/controlled.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2021-08-02T20:18:43.050" LastActivityDate="2021-08-02T20:18:43.050" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22638" PostTypeId="1" CreationDate="2021-08-01T08:39:08.717" Score="5" ViewCount="94" Body="&lt;p&gt;A long time ago I did some reading on Mie scattering and atmospheric particulate counting and I got sidetracked on raindrop characterization.&lt;/p&gt;&#xA;&lt;p&gt;I remember reading about light and laser based scatterometers that measured dark pulses as water droplets passed through the beam between a light source and a detector and attenuated it, and also bright pulses seen in detectors off to the side that recorded small and large angle scattered light from the water droplets.&lt;/p&gt;&#xA;&lt;p&gt;Analysis of histograms of the amplitudes of the bright and dark pulses and to some extent other parameters allowed for an analysis of droplet size frequencies along the path that an aircraft flew in real time.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What are those optical precipitation and water droplet characterization instruments called that they put on meteorological aircraft? How do they work?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2022-04-29T01:51:25.097" LastActivityDate="2022-04-29T01:51:25.097" Title="What are those precipitation and water droplet characterization instruments called that they put on meteorological aircraft? How do they work?" Tags="|meteorology|precipitation|remote-sensing|rain|instrumentation|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22639" PostTypeId="1" AcceptedAnswerId="22727" CreationDate="2021-08-01T14:00:49.500" Score="13" ViewCount="1270" Body="&lt;p&gt;Except near thermal vents, the deep ocean is generally considered to be quite cool. For instance, water temps in the Mariana Trench (~10 km deep) are 1-4 °C.&lt;/p&gt;&#xA;&lt;p&gt;However, the geothermal gradient runs counter to that, where the lithosphere at the same 10km depth would be around 250-300 °C.&lt;/p&gt;&#xA;&lt;p&gt;So, in a sense, water should be heated from beneath and only be able to release its energy into the atmosphere/space. Yet, we see the exact opposite of this, where the upper layers are the warmest.&lt;/p&gt;&#xA;&lt;p&gt;Where did the thermal energy go? Is it the product of billions of years of ocean currents carrying the heat to the poles, or am I overlooking some other principle?&lt;/p&gt;&#xA;" OwnerUserId="23136" LastEditorUserId="23136" LastEditDate="2021-08-24T17:16:31.013" LastActivityDate="2021-08-24T17:16:31.013" Title="Why is the deep sea cold?" Tags="|oceanography|geothermal-heat|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22640" PostTypeId="1" CreationDate="2021-08-01T15:44:02.633" Score="11" ViewCount="1716" Body="&lt;p&gt;i hope this question fits here.&lt;/p&gt;&#xA;&lt;p&gt;In my local nature reserve there is an &amp;quot;art&amp;quot; project... but the local population has it's concerns.&lt;/p&gt;&#xA;&lt;p&gt;Seeing most things seem to be random trash thrown in (like the engine of an old oil tanker).&lt;/p&gt;&#xA;&lt;p&gt;One of those art projects is this giant ball of sugar and food coloring... (no further detail given on what it is made of)&lt;/p&gt;&#xA;&lt;p&gt;The &amp;quot;art&amp;quot; in question:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/UHA69.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UHA69.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Does this...sugarball pose any danger to the local fauna/flora?&lt;/p&gt;&#xA;&lt;p&gt;(the landscape is moors, with some forest area's. Animals include Deer, cows, sheep, goats, horses, donkeys, foxes, snakes, frogs, lizards and a large variety of bugs)&lt;/p&gt;&#xA;" OwnerUserId="23137" LastEditorUserId="22648" LastEditDate="2021-08-03T17:35:31.440" LastActivityDate="2021-08-04T19:12:07.083" Title="Impact of Sugar on the environment" Tags="|soil|pollution|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="22641" PostTypeId="2" ParentId="22639" CreationDate="2021-08-01T16:28:22.330" Score="2" Body="&lt;p&gt;Cold water is denser than warm water. The very cold water in the Arctic and Antarctic regions sinks and circulates deep undersea.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2021-08-01T16:28:22.330" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="22642" PostTypeId="2" ParentId="22640" CreationDate="2021-08-01T17:00:00.253" Score="10" Body="&lt;p&gt;Sugar can be used as a &lt;a href=&quot;https://www.gardeningknowhow.com/special/organic/using-sugar-to-kill-weeds.htm&quot; rel=&quot;noreferrer&quot;&gt;weed killer&lt;/a&gt;, particularly broad leaf weeds, rather than grasses or perennials. It is a carbon nutrient that contains no nitrogen. Sugar can limit the growth of plant that do not tolerate low nitrogen environments.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This is because microorganisms in soil are forced to source their necessary nitrogen from soil. This leaves little for weed growth.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The other effect of &lt;a href=&quot;https://www.gardenguides.com/99900-effects-sugar-water-plants.html&quot; rel=&quot;noreferrer&quot;&gt;high sugar concentrations&lt;/a&gt; on plants is,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;If you feed your plant a strong solution of sugar water, you create a situation in which the water outside its cells has a higher percentage of soluble material than does the water inside. The direction of osmosis reverses, causing water to exit plant cells or not be able to enter in the first place. The plant begins to die.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;As for the effect on animals, some animals will be attracted by the sugar, causing them to frequent the area for a sugar fix. Such animals could fall prey to cunning foxes.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-08-01T17:00:00.253" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22643" PostTypeId="2" ParentId="16652" CreationDate="2021-08-01T23:10:57.040" Score="4" Body="&lt;p&gt;I take your question as the question about &lt;em&gt;first&lt;/em&gt; scattering event, ignoring all the subsequent ones (because they bounce light rays between the top and bottom halves of atmosphere). Also, I'm assuming daylight conditions, like 45° solar elevation.&lt;/p&gt;&#xA;&lt;p&gt;Let's look at a simulation I did using my &lt;a href=&quot;https://github.com/10110111/CalcMySky&quot; rel=&quot;nofollow noreferrer&quot;&gt;CalcMySky&lt;/a&gt; software. Here's how the first scattering order luminance looks in equirectangular projection for an observer at &lt;span class=&quot;math-container&quot;&gt;$1\,\mathrm m$&lt;/span&gt; altitude:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rLIIY.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rLIIY.png&quot; alt=&quot;&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now the same for &lt;span class=&quot;math-container&quot;&gt;$5500\,\mathrm m$&lt;/span&gt; altitude:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/b7VNr.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/b7VNr.png&quot; alt=&quot;&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;For completeness, let's also see the same from &lt;span class=&quot;math-container&quot;&gt;$25\,500\,\mathrm m$&lt;/span&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3rbcy.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3rbcy.png&quot; alt=&quot;&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So, you're basically right: &lt;span class=&quot;math-container&quot;&gt;$5500\,\mathrm m$&lt;/span&gt; is roughly the altitude where first scattering contribution is the same from below and from above the observer.&lt;/p&gt;&#xA;" OwnerUserId="12360" LastActivityDate="2021-08-01T23:10:57.040" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22644" PostTypeId="1" AcceptedAnswerId="22645" CreationDate="2021-08-02T02:26:55.587" Score="4" ViewCount="687" Body="&lt;p&gt;I’m working on a terrain generator and I now need to color the terrain to be rock, grass, or snow. Ignoring snow for now, at first I thought I’d make flatter areas grass and make steeper areas rock. But pictures like this can’t be explained only with elevation and slope. &lt;a href=&quot;https://i.stack.imgur.com/t8xF7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/t8xF7.jpg&quot; alt=&quot;Scottish Mountain&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;They still play a role, but there are areas with the same slope next to each other where one is covered with grass and the other is covered with rock.  &lt;strong&gt;What other forces or processes are affecting grass placement that I need to consider when coloring my terrain?&lt;/strong&gt; Do I need to think about wind or water erosion? Maybe the type of rock? I’m only interested in grass placement on mountains like the picture has, not how it might change with different climates.&lt;/p&gt;&#xA;&lt;p&gt;I’m guessing my question is really more about soil placement than grass since grass will mostly be where dirt is, so you can choose to answer the question either way.&lt;/p&gt;&#xA;&lt;p&gt;Bonus for what causes those areas with dirt and no grass.&lt;/p&gt;&#xA;&lt;p&gt;Thanks.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt;&#xA;I changed my code to color the terrain based on slope &lt;strong&gt;and&lt;/strong&gt; “exposure” which I measured by height above or below the surrounding average height. Sorry that the results are pretty simple and not very neat, but the grass placement looks a lot more realistic than before thanks to considering how vulnerable parts of the terrain are to high winds.&#xA;&lt;img src=&quot;https://i.stack.imgur.com/iQJ4n.jpg&quot; alt=&quot;Perlin noise mountains rendered in Blender&quot; /&gt;&lt;/p&gt;&#xA;" OwnerUserId="23140" LastEditorUserId="23140" LastEditDate="2021-08-04T18:24:16.557" LastActivityDate="2021-08-04T18:24:16.557" Title="What affects where a terrain will be rocky or grassy?" Tags="|geology|geophysics|geography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22645" PostTypeId="2" ParentId="22644" CreationDate="2021-08-02T04:27:19.740" Score="4" Body="&lt;p&gt;Ignoring the effect of overgrazing by animals, you have already touched on many things that affect where grass will grow: elevation, slope, geology - particularly soil cover, water erosion and wind.&lt;/p&gt;&#xA;&lt;p&gt;Three others are ground moisture, for which soil plays a very important role, temperature and exposure to sun light - particularly where surface features can produce long lasting shadows.&lt;/p&gt;&#xA;&lt;p&gt;Parts of slopes can be protected from wind and be localized warmer spots. If such spots have enough soil and moisture grass will grow. This will be influenced by the way air moves around the terrain, particularly the higher terrain. The cragginess of the higher terrain can affect the formation of thermals and localized small scale atmospheric vortices.&lt;/p&gt;&#xA;&lt;p&gt;Also, depending on geographical location, excessive exposure to sunlight can make some rock faces too hot for grass to grow.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-08-02T04:27:19.740" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22646" PostTypeId="2" ParentId="22640" CreationDate="2021-08-02T16:00:59.667" Score="3" Body="&lt;p&gt;If there are any beehives in the area, it's likely the bees will discover this and go to it preferentially over other sources of sugars. That will reduce their utility to the beekeeper by removing their pollinating effects and by filling the combs with artificial honey that is likely an unappetizing color to boot. Finally, it's possible that the ingredients of the gobstopper (high fructose corn syrup) will be &lt;a href=&quot;https://www.beeculture.com/a-closer-look-feeding-sugar-syruphmi/&quot; rel=&quot;nofollow noreferrer&quot;&gt;harmful to them&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Due to the ease of handling HFCS over mixing sucrose solutions and cheaper pricing, the use of HFCS for bee feed increased rapidly. However, questions about the safety of HFCS as a bee food were raised soon after it became available, because beekeepers reported mixed results from feeding it (Bailey 1966; Johansson and Johansson 1976, 1977; Anonymous 1996). In addition, researchers found decreased longevity in worker bees maintained in the laboratory on HFCS as compared to honey (Barker and Lehner 1978) or to sucrose syrup (Weiss 2009).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="23148" LastActivityDate="2021-08-02T16:00:59.667" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22647" PostTypeId="1" CreationDate="2021-08-02T20:16:29.000" Score="12" ViewCount="2529" Body="&lt;p&gt;I've tried searching for this myself, but Google is saturated with the Greenhouse Gases angle of Rising Global Temperatures.&lt;/p&gt;&#xA;&lt;p&gt;What I'm interested in is the following:&lt;/p&gt;&#xA;&lt;p&gt;Greenhouse gases aside, to what extent do automobiles directly contribute to a rising global temperature? Has a study ever been done? Is it even a tiny portion? It seems like there are hundreds of miles of roads covered in 200-degree heaters. That heat has to go somewhere!&lt;/p&gt;&#xA;&lt;p&gt;I saw the term &amp;quot;Thermal Pollution&amp;quot; come up, and that sounds like it could be what I'm thinking of.&lt;/p&gt;&#xA;&lt;p&gt;I often see folks hanging out in their vehicle idling with the AC Running, and think about how inefficient it is. Of course, A/C systems simply &amp;quot;move&amp;quot; the heat from inside the vehicle to outside of it- But an idling engine in the mix is just a huge waste.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LwaLK.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LwaLK.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20916" LastEditorUserId="20916" LastEditDate="2021-08-03T21:33:50.927" LastActivityDate="2023-09-04T11:27:37.430" Title="Have there been any studies on how vehicles directly contribute to a rising global temperature?" Tags="|climate-change|" AnswerCount="2" CommentCount="13" ContentLicense="CC BY-SA 4.0" />
  <row Id="22649" PostTypeId="2" ParentId="22647" CreationDate="2021-08-03T00:14:46.960" Score="22" Body="&lt;p&gt;Waste heat from vehicles &lt;strong&gt;pales in comparison to the energy from the sun.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;In 2018, &lt;a href=&quot;https://www.iea.org/data-and-statistics/data-browser?country=WORLD&amp;amp;fuel=Energy%20consumption&amp;amp;indicator=TFCShareBySector&quot; rel=&quot;noreferrer&quot;&gt;total global energy consumption for transport&lt;/a&gt; (including road, rail, air, and sea) was 2,890,900 ktoe (kilotonnes oil equivalent), or 330 ktoe per hour (dividing through by 8,760). This &lt;a href=&quot;https://www.unitjuggler.com/convert-energy-from-ktoe-to-Wh.html?val=330&quot; rel=&quot;noreferrer&quot;&gt;converts to&lt;/a&gt; 3,837,900,000,000 watts consumed on the earth's surface in an average hour.&lt;/p&gt;&#xA;&lt;p&gt;The global surface area of Earth is 510,067,420 km&lt;sup&gt;2&lt;/sup&gt;. Dividing through, this works out to 7,525 W per km&lt;sup&gt;2&lt;/sup&gt;, or &lt;strong&gt;0.0075 W/m&lt;sup&gt;2&lt;/sup&gt;&lt;/strong&gt;. This assumes that all energy used by vehicles ends up as heat, which is a rough assumption, as only &lt;a href=&quot;https://www.fueleconomy.gov/feg/atv.shtml&quot; rel=&quot;noreferrer&quot;&gt;12 to 30% of the energy used by a car&lt;/a&gt; is converted to kinetic energy.&lt;/p&gt;&#xA;&lt;p&gt;In contrast, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_irradiance#Irradiance_on_Earth%27s_surface&quot; rel=&quot;noreferrer&quot;&gt;sun radiates&lt;/a&gt; an average of 340 W/m&lt;sup&gt;2&lt;/sup&gt; to the Earth's surface.&lt;/p&gt;&#xA;&lt;p&gt;This is why, despite being &lt;a href=&quot;https://news.energysage.com/what-are-the-most-efficient-solar-panels-on-the-market/&quot; rel=&quot;noreferrer&quot;&gt;only 20% efficient&lt;/a&gt;, solar PV could power the world if &lt;a href=&quot;https://landartgenerator.org/blagi/archives/127&quot; rel=&quot;noreferrer&quot;&gt;each country had 100 km&lt;sup&gt;2&lt;/sup&gt; array&lt;/a&gt;, or about 500,000 km&lt;sup&gt;2&lt;/sup&gt; globally. That's a lot, but still less than 1/10 of a percent of the earth's total surface area.&lt;/p&gt;&#xA;&lt;p&gt;As comments have pointed out, &lt;em&gt;directly&lt;/em&gt; comparing waste heat from vehicles to solar irradiance isn't valid, as these energy sources are coming from and going to different places. But understanding how much greater the sun's energy is (by a factor of nearly 50,000) helps explain why there's more concern about the heat-trapping CO&lt;sub&gt;2&lt;/sub&gt; from vehicle exhaust, then the heat they directly put into the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="7741" LastEditorUserId="7741" LastEditDate="2021-08-03T12:59:15.690" LastActivityDate="2021-08-03T12:59:15.690" CommentCount="17" ContentLicense="CC BY-SA 4.0" />
  <row Id="22650" PostTypeId="2" ParentId="22647" CreationDate="2021-08-03T22:20:31.683" Score="1" Body="&lt;p&gt;Going off the conversation in comments on another answer, I'm converting that info into an Answer.&lt;/p&gt;&#xA;&lt;p&gt;From a 2017 article on Nature.com, compared to the heat being captured by greenhouse gasses, anthropogenic waste heat only accounts for about 1% of the temperature increase globally.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Nearly 70% of energy is consumed within cities occupying a mere 2% of the Earth’s surface area, and future scenarios indicate that global primary energy consumption will rise 1.6 times (864.7 quadrillion kJ) from 2010 to 2040 (&lt;a href=&quot;http://www.worldenergyoutlook.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.worldenergyoutlook.org/&lt;/a&gt;). Although anthropogenic heat accounts for only 1% of the greenhouse gas forcing, it causes the majority of regional warming, such as urban heat islands1,2, urban boundary heights, and hourly intensity of precipitation at the city level2–5, especially at night.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/sdata2017116&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/sdata2017116&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This article says that most of the problems caused by this issue are local to the regions creating it. Cities, industries, etc. are all creating this waste heat, but it dissipates as the distance to it increases. This means it's not a significant global issue, but it is an issue that needs to be addressed. We just need to realize that we can't ignore the 99% problem of greenhouse gasses to fix the 1% problem instead.&lt;/p&gt;&#xA;&lt;p&gt;Some of these problems have been studied since 2006 and earlier. According to the 2020 article (on the right half of the screen), this was considered a significant enough problem to be looked into that the Osaka Heat Island Countermeasure Technology Consortium (HITEC) was created. There's also articles from 2013 and 1993 talking about this issue, so it's been looked at considerably, but the only place I can find a number assigned to the amount of this effect is from the Nature article I first referenced.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Osaka Heat Island Countermeasure Technology Consortium (HITEC) was established in January 2006, for the purpose of the development and spread of heat island countermeasure technologies, implementation of measures and verification of their effects, and the collaboration between industry, academia, government, and the private sectors [15].&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/topics/engineering/anthropogenic-heat&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/topics/engineering/anthropogenic-heat&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This next article doesn't say how much this effect causes heating compared to greenhouse gasses alone, but it confirms that it's a fairly local problem in section 2. It also says that to help reduce this effect, we need to reduce the creation of greenhouse gasses. From how I read it, this means that anthropogenic waste heat and greenhouse gasses aren't two different problems, but intertwined. Not to mention that most of this anthropogenic waste heat is created by industries and homes releasing greenhouse gasses to create the heat they use and release.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Cool roofs reduce building heat-gain, create saving air conditioning expenditures, enhance the life expectancy of both the roof membrane and the building’s cooling equipment, improve thermal efficiency of the roof insulation, reduce the demand for electric power, reduce resulting air pollution and greenhouse gas emissions, provide energy savings, and mitigate UHI effects.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.hindawi.com/journals/usr/2011/497524/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.hindawi.com/journals/usr/2011/497524/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18672" LastActivityDate="2021-08-03T22:20:31.683" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22653" PostTypeId="2" ParentId="22640" CreationDate="2021-08-04T19:12:07.083" Score="2" Body="&lt;p&gt;I had an 2 hour meeting with the local park ranger about this and the other exhibits, the ball is getting removed due to a high number of insects (mainly butterflies and moths) getting stuck on it and dying.&lt;/p&gt;&#xA;" OwnerUserId="23137" LastActivityDate="2021-08-04T19:12:07.083" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22654" PostTypeId="2" ParentId="22631" CreationDate="2021-08-05T06:50:13.733" Score="4" Body="&lt;p&gt;No agency is running 1-km forecasts globally... and certainly not out 14 days.  The only 1-km forecasts I have heard of are for small regions and just 2 days. If you can live with coarser data, &lt;a href=&quot;https://weather.us/model-charts&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weather.us&lt;/a&gt; has a nice list of available global forecast models out there (below), and they also have a list of regional forecast models.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Global Forecast Models:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;ECMWF HRES (~ 9 km; 10 days)&lt;/li&gt;&#xA;&lt;li&gt;ECMWF EPS (~14 km; 10 days)&lt;/li&gt;&#xA;&lt;li&gt;ICON (~13 km; 7 days)&lt;/li&gt;&#xA;&lt;li&gt;GFS (~23 km; 15 days)&lt;/li&gt;&#xA;&lt;li&gt;GEFS (~46 km; 15 days)&lt;/li&gt;&#xA;&lt;li&gt;UKMO (~17 km; 6 days)&lt;/li&gt;&#xA;&lt;li&gt;GEM (~22 km; 10 days)&lt;/li&gt;&#xA;&lt;li&gt;ACCESS-G (~27 km; 10 days)&lt;/li&gt;&#xA;&lt;li&gt;ARPEGE (~46 km; 5 days)&lt;/li&gt;&#xA;&lt;li&gt;CMA (~23 km; 10 days)&lt;/li&gt;&#xA;&lt;li&gt;GDAPS/UM (~10 km; 12 days)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="543" LastActivityDate="2021-08-05T06:50:13.733" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22655" PostTypeId="2" ParentId="22632" CreationDate="2021-08-05T11:22:17.260" Score="4" Body="&lt;p&gt;The approach adopted by &lt;a href=&quot;https://en.wikipedia.org/wiki/Charles_Lyell&quot; rel=&quot;nofollow noreferrer&quot;&gt;Charles Lyell&lt;/a&gt; (and other writers in a similar timeframe), in his book &lt;a href=&quot;https://archive.org/details/principlesgeolo05lyelgoog/page/n3/mode/2up&quot; rel=&quot;nofollow noreferrer&quot;&gt;'Principles of Geology'&lt;/a&gt; which was first published in the 1830s was to look at processes in the modern landscape where the rate of change could be determined by observation or from historical evidence, and assuming that similar processes operated at similar rates in the geological past. So, for instance, if you measure the amount of sediment transported by a river today, and you measure the volume of sediment in that river's delta, you can estimate how long that delta took to form. If you see a similar delta  in the geological record, you can assume it took a similar time to form. Lyell's estimates of the age of the earth were low, but as the concept of plate tectonics, with it's progressive recycling of rocks through subduction wasn't recognised, it was remarkably prescient.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastEditorUserId="21585" LastEditDate="2021-08-05T21:46:23.563" LastActivityDate="2021-08-05T21:46:23.563" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22656" PostTypeId="1" CreationDate="2021-08-05T19:46:04.267" Score="5" ViewCount="174" Body="&lt;p&gt;Apologies if this question may not be up to mark for this stack. I initially asked this on the world building stack but with the lack of replies, I thought I might try my luck here. The main premise is to cool the Indian subcontinent and stave off deaths related to unbearable wet bulb temperatures using the difference in temp of the Tibetan plateau. Thank You!&#xA;Copy Pasta -&lt;/p&gt;&#xA;&lt;p&gt;The Indian subcontinent is at the same latitude as the Sahara desert, and if not for the Tibetan Plateau reversing the Haileys cell (?), would have the same environment. The plateau causes rain in the north, and the Arabian Sea and the Bay of Bengal to the south push moisture into the southern peninsula. But still, with global warming, the threat of wet bulb temperatures is increasing and the heat may prove unsustainable for the most populated region in the world. Here is a temperature map - &lt;a href=&quot;https://i.stack.imgur.com/m4ewR.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/m4ewR.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It is clear that there is a massive and sudden temp change from 0 or even -10 degrees C to 25 or 30 degrees C in India. That is at the minimum a temp difference of 25 C or at the maximum 40 C. If the plateau could be terraformed to allow the cold winds of the north to move south like a ramp (hot are rises, cold air falls) it could cool the subcontinent, and lead to more rainfall (idk maybe). It may even pull in the freezing air of the Siberian anticyclone for further cooling. It may also raise temp of Mongolia for better living conditions. Also the convection belt that forms might have high wind speeds for wind power making it a powerhouse for renewables. The last thing of the top of my head is that the arctic would cool faster? Russia might not be coldest place in world anymore. Arctic shipping lane opens up which is big for china and its export economy. Also tibet would be much more habitable opening up much more land? Win win win for China India Russia Mongolia? Myanmar might be better as a test run due to the mountains flanking the Central Valley acting as a better channel for the cold air. But that's geopolitical and I digress. With that out of the way, my main questions are.&lt;/p&gt;&#xA;&lt;p&gt;Is it theoretically possible? What would it look like? Temperatures in India would fall by how much? Is it economical in the super long term? Impact on globe net positive or negative? Runaway global warming leads to planet heat death? Completely unrelated, how does the rain thing work lol its so confusing what causes rain in certain areas and not others lol...?&lt;/p&gt;&#xA;&lt;p&gt;Thank you for reading this long ass post (-:&lt;/p&gt;&#xA;" OwnerUserId="23184" LastActivityDate="2021-08-05T22:22:54.410" Title="Cooling the Indian subcontinent using Tibetan Plateau" Tags="|climate|planetary-science|geoengineering|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22657" PostTypeId="2" ParentId="22656" CreationDate="2021-08-05T22:22:54.410" Score="4" Body="&lt;p&gt;First things first: This is an extremely, massively bad idea because except for a few places, there are intervening countries between India and the Tibetan Plateau. Those other countries are not going to like it when India blasts a valley through the Himalaya.&lt;/p&gt;&#xA;&lt;p&gt;More importantly, this an extremely bad idea because it will have exactly the opposite of the intended effect. One problem is that it won't work all the time. You'll need a high pressure cell over the Tibetan Plateau for the air to flow downward. But then when it does work, it won't do what you think.&lt;/p&gt;&#xA;&lt;p&gt;Suppose you do manage to convince India to blast a ten km wide set of valleys through the western Himalaya so that air can flow from the plateau down toward New Delhi. That down-flowing air will form a &lt;a href=&quot;https://en.wikipedia.org/wiki/Katabatic_wind&quot; rel=&quot;nofollow noreferrer&quot;&gt;katabatic&lt;/a&gt; wind.&lt;/p&gt;&#xA;&lt;p&gt;The down-flowing air will heat at the &lt;a href=&quot;https://www.oxfordreference.com/view/10.1093/oi/authority.20110803095732430&quot; rel=&quot;nofollow noreferrer&quot;&gt;dry adiabatic lapse rate&lt;/a&gt;, 9.8 °C per kilometer of altitude drop. Assuming a four kilometer altitude difference between the top of the channel toward New Delhi and New Delhi itself, than means a 39.2 °C increase in the temperature from the point of collection and the temperature when the wind hits New Delhi.&lt;/p&gt;&#xA;&lt;p&gt;While the Tibetan Plateau is cool because of its altitude, it is not as cool as one would naively think. The highest timberlines in the northern hemisphere are at the southern edges of the Tibetan Plateau. There's a reason for this: &lt;a href=&quot;https://scholar.google.com/scholar?hl=en&amp;amp;q=Heating+Effect+of+the+Tibetan+Plateau&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Tibetan Plateau has a significant heating effect on the upper atmosphere&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Suppose a high pressure cell does set up over the Tibetan Plateau, raising the air temperature to a very pleasant 21 °C at the collection point. That air will be a deadly 60 °C by the time it descends on New Delhi, and the relative humidity will be in the low single digits. This is a deadly combination.&lt;/p&gt;&#xA;&lt;p&gt;A similar phenomenon called the &lt;a href=&quot;https://en.wikipedia.org/wiki/Santa_Ana_winds&quot; rel=&quot;nofollow noreferrer&quot;&gt;Santa Ana winds&lt;/a&gt; happens every year in southern California. Natural channels in the Sierra Nevada and the coastal mountains allow air to flow from the US southwest's high desert toward the southern California coast when conditions are right. The adiabatic heating makes autumn the time of the year when the highest temperatures are recorded near the souther California coast.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2021-08-05T22:22:54.410" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22658" PostTypeId="2" ParentId="19439" CreationDate="2021-08-06T00:23:31.240" Score="2" Body="&lt;p&gt;To answer your question, &amp;quot;&lt;em&gt;...surely there have been cases where we have found new fossils that we have no way of knowing the age?&lt;/em&gt;&amp;quot;, the short answer is yes.&lt;/p&gt;&#xA;&lt;p&gt;Prior to modern radiometric dating in the early 1900s, which placed firm constraints on age, you could say that &lt;strong&gt;all&lt;/strong&gt; fossils found until that point were of unknown age. Sure, you could establish depositional constraints: this fossil is older because it lies under that one, but no one knew how old, relative to the age of the earth, it was, or how old relative to each other they were.&lt;/p&gt;&#xA;&lt;p&gt;For a long time, at least throughout Europe, the Bible was the chief source of all information and natural philosophers assumed fossils were victims of The Great Flood. If you spent all of your time studying the bible for clues for when God created everything, you'd back-calculate that nothing on earth could be older than about 4,000 years old. They were derided as &amp;quot;Antediluvialists&amp;quot; by later generations of thinkers for whom the concept of deep time was a very real possibility. Even Lord Kelvin, the smartest man in the world at the time, couldn't understand why fossils needed to be so old.&lt;/p&gt;&#xA;&lt;p&gt;Discounting Tinder, it's impossible to find an undatable fossil, even those that have survived metamorphism.&lt;/p&gt;&#xA;&lt;p&gt;An analogous situation existed for European history. Prior to carbon dating, it was believed that all of European culture was derived from the Greeks, as it was (by circular reasoning) the &amp;quot;oldest&amp;quot; that anyone could find because all artifacts found throughout Europe had to be derivations.&lt;/p&gt;&#xA;&lt;p&gt;When carbon dating revealed European cultures pre-dating the Greeks by thousands of years, an entire school of thought that lasted centuries, vanished literally overnight.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2021-08-06T00:23:31.240" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22659" PostTypeId="1" AcceptedAnswerId="22660" CreationDate="2021-08-06T00:23:37.410" Score="9" ViewCount="1176" Body="&lt;p&gt;Today's The Guardian headline was that &lt;a href=&quot;https://www.theguardian.com/environment/2021/aug/05/climate-crisis-scientists-spot-warning-signs-of-gulf-stream-collapse&quot; rel=&quot;noreferrer&quot;&gt;Climate crisis: Scientists spot warning signs of Gulf Stream collapse&lt;/a&gt;. It reminded an old movie called &amp;quot;The Day After Tomorrow&amp;quot;, which suggested the possible global events if the north Atlantic current got stopped.&lt;/p&gt;&#xA;&lt;p&gt;As one had been told, the movie in the recent years took a great interest in the scientific correctness, such as the movie &amp;quot;Interstellar&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Thus, how authentic was the movie scene in &amp;quot;The Day After Tomorrow&amp;quot; related to the understanding of the North Atlantic current system? Would the Gulf stream actually do it? If so then to what extend would it be?&lt;/p&gt;&#xA;" OwnerUserId="23185" LastEditorDisplayName="user20559" LastEditDate="2021-09-02T11:28:58.297" LastActivityDate="2021-09-02T11:28:58.297" Title="How authentic was the movie scene in &quot;The day after tomorrow&quot; related to the understanding of the north Atlantic current system?" Tags="|climate|oceanography|ocean-currents|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22660" PostTypeId="2" ParentId="22659" CreationDate="2021-08-06T14:11:50.633" Score="13" Body="&lt;p&gt;&lt;a href=&quot;https://www.imdb.com/title/tt0319262/trivia?item=tr0760057&quot; rel=&quot;noreferrer&quot;&gt;I'm not sure how much I can comment about it, but here we go (that's a joke... maybe).&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Is it realistic in the collapse of the current system? &lt;a href=&quot;https://www.businessinsider.com/day-after-tomorrow-was-right-and-wrong-about-climate-shifts-2019-3&quot; rel=&quot;noreferrer&quot;&gt;Well kind of&lt;/a&gt;, but not in the timespan that is suggested. But that was a big part of the movie. It has also been mentioned to me that in one of the points of the movie, they actually show the thermohaline circulation going in reverse, but that is the least of my concern (and I am not about to rewatch the entire movie for the 5 second clip that I couldn't show you).&lt;/p&gt;&#xA;&lt;p&gt;Is it realistic in the effects of that movie? No, absolutely not. No, synoptic scale low pressure systems  are restricted in size to the length scale of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Rossby_radius_of_deformation&quot; rel=&quot;noreferrer&quot;&gt;Rossby Radius of Deformation.&lt;/a&gt; Moreover, the sinking of air would actually increase the temperature of the air, similar to &lt;a href=&quot;https://en.wikipedia.org/wiki/Chinook_wind&quot; rel=&quot;noreferrer&quot;&gt;Chinook winds&lt;/a&gt; (called &lt;a href=&quot;https://en.wikipedia.org/wiki/Adiabatic_process&quot; rel=&quot;noreferrer&quot;&gt;adiabatic warming&lt;/a&gt;). A &amp;quot;back of the envelope&amp;quot; estimation of this is that air brought from the tropopause to the surface could be approximately 188°F (87°C), as the dry adiabatic lapse rate is 10°C/km, &lt;a href=&quot;https://en.wikipedia.org/wiki/Stratosphere&quot; rel=&quot;noreferrer&quot;&gt;the height being 10 km in the midlatitudes at a temperature of about 260 K.&lt;/a&gt; Then, &lt;a href=&quot;https://weatherworksinc.com/news/high-low-pressure&quot; rel=&quot;noreferrer&quot;&gt;there is the issue of sinking air being associated with high pressure (clear skies, as the warming air evaporates water and is usually dry as there is less water further from the surface), and not low pressure.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So is it accurate? In terms of the circulation, they only fast forwarded a couple hundred to thousand years. But even that statement is inaccurate to some extent, as &lt;a href=&quot;https://en.wikipedia.org/wiki/Shutdown_of_thermohaline_circulation&quot; rel=&quot;noreferrer&quot;&gt;it is projected to weaken, rather than collapse outright.&lt;/a&gt; In terms of the meteorology/climatology, absolutely not. &lt;a href=&quot;https://www.imdb.com/title/tt0319262/trivia?item=tr1164565&quot; rel=&quot;noreferrer&quot;&gt;Still, it's enjoyable nonsense.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-08-06T14:11:50.633" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22661" PostTypeId="1" AcceptedAnswerId="23542" CreationDate="2021-08-07T01:40:02.700" Score="4" ViewCount="1034" Body="&lt;p&gt;Meteorological phenomenon can span large ranges in size and strength and categorizations exist based on thresholds, One example is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Saffir%E2%80%93Simpson_scale&quot; rel=&quot;nofollow noreferrer&quot;&gt;Saffir–Simpson hurricane wind scale (SSHWS)&lt;/a&gt; (see also &lt;a href=&quot;https://www.nhc.noaa.gov/aboutsshws.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://commons.wikimedia.org/wiki/Category:Tropical_Storm_Lupit_(2021)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tropical Depression TD11 (LUPIT)&lt;/a&gt; will be passing by and I saw an &lt;a href=&quot;https://www.cwb.gov.tw/V8/E/P/Warning/W26.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Extremely Heavy Rain Advisory&lt;/a&gt; with a color-coded map of counties in Taiwan categorized as&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Heavy Rain (yellow)&lt;/li&gt;&#xA;&lt;li&gt;Extremely Heavy Rain (orange)&lt;/li&gt;&#xA;&lt;li&gt;Torrential Rain (red)&lt;/li&gt;&#xA;&lt;li&gt;Extremely Torrential Rain (purple)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;update:&lt;/strong&gt; It's been pointed out that there is a &amp;quot;descriptions tab&amp;quot; on the page which says:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Heavy Rain: 24-hour accumulated rainfall exceeds 80 millimeters, or 1-hour rainfall exceeds 40 millimeters.&lt;/li&gt;&#xA;&lt;li&gt;Extremely Heavy Rain: 24-hour accumulated rainfall exceeds 200 millimeters, or 3-hour accumulated rainfall exceeds 100 millimeters.&lt;/li&gt;&#xA;&lt;li&gt;Torrential Rain: 24-hour accumulated rainfall exceeds 350 millimeters, or 3-hour accumulated rainfall exceeds 200 millimeters.&lt;/li&gt;&#xA;&lt;li&gt;Extremely Torrential Rain: 24-hour accumulated rainfall exceeds 500 millimeters.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I'm curious if these four descriptions are standardized categories or are simply chosen here to give a sense of increasingness to the progression in color and severity of rainfall.&lt;/p&gt;&#xA;&lt;p&gt;So I'd like to ask:&lt;/p&gt;&#xA;&lt;p&gt;Are terms like &amp;quot;Extremely Torrential Rain&amp;quot; universal in meteorology? Are these standardized categories widely used in meteorology or are these &lt;em&gt;ad hoc&lt;/em&gt; definitions for this weather service?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Screenshot from &lt;a href=&quot;https://www.cwb.gov.tw/V8/E/P/Warning/W26.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.cwb.gov.tw/V8/E/P/Warning/W26.html&lt;/a&gt; circa &lt;code&gt;01:30 07-Aug-2021 UTC&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Rh5KK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Rh5KK.png&quot; alt=&quot;Extremely Torrential Rain from https://www.cwb.gov.tw/V8/E/P/Warning/W26.html circa 01:30 07-Aug-2021 UTC&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2021-08-07T08:53:27.527" LastActivityDate="2022-02-17T12:14:36.330" Title="Are terms like &quot;Extremely Torrential Rain&quot; (&gt;500 mm/24 hours) universal in meteorology?" Tags="|meteorology|tropical-cyclone|rainfall|terminology|rain|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22662" PostTypeId="1" AcceptedAnswerId="23520" CreationDate="2021-08-07T14:59:46.633" Score="6" ViewCount="178" Body="&lt;p&gt;The Science at NASA video &lt;a href=&quot;https://www.youtube.com/watch?v=hN0wGga5e0I&quot; rel=&quot;noreferrer&quot;&gt;ScienceCasts: Dark Lightning&lt;/a&gt; describes observation of gamma rays from Earth by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Fermi_Gamma-ray_Space_Telescope&quot; rel=&quot;noreferrer&quot;&gt;Fermi Gamma-ray Space Telescope&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;These gamma rays are associated with weather that produces lightning, but the actual mechanism for gamma ray production &lt;em&gt;by weather&lt;/em&gt; was still uncertain at the time.&lt;/p&gt;&#xA;&lt;p&gt;The video explains that a discharge mechanism called &amp;quot;Dark Lightning&amp;quot; might produce the gamma rays without producing the same visible light signatures that normal lightning produces.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Did Dark Lightning turn out to be a real thing? Is this what produces gamma ray flashes from lightning storms?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Screen shot from the video shows a graphic of a booklet with the following words on its cover:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;AGU Fall Meeting, San Francisco, 3-7 December 2012&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Yirip.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Yirip.jpg&quot; alt=&quot;AGU Fall Meeting, San Francisco, 3-7 December 2012&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2021-08-08T13:03:09.020" LastActivityDate="2022-02-11T17:55:08.987" Title="Did Dark Lightning turn out to be a real thing? Is this what produces gamma ray flashes from lightning storms?" Tags="|meteorology|lightning|electromagnetism|ionizing-radiation|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22663" PostTypeId="1" AcceptedAnswerId="22664" CreationDate="2021-08-07T15:01:36.797" Score="22" ViewCount="5836" Body="&lt;p&gt;Apologies for asking a silly question like this. But I want to offer some points which I could not counter, as follows:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Ice is less dense than water, that is why it floats. For the same unit mass, if density is lowered, the volume increases, thus ice ends up having more volume/consuming more space.&lt;/li&gt;&#xA;&lt;li&gt;AFAIK, the polar ice on Earth does not originate from other planets.&lt;/li&gt;&#xA;&lt;li&gt;Above points conclude that, if polar glaciers continue to melt (very unfortunate) the resulting water is denser than the ice so it would occupy less volume per unit mass and as the polar glaciers were originally from Earth, there is no new volume addition which can explain the rising sea levels.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;So how does glacial melting cause global water levels to rise? Are there other factors which amplify this, like maybe global &lt;a href=&quot;https://www.iucn.org/resources/issues-briefs/marine-plastics&quot; rel=&quot;noreferrer&quot;&gt;polymer waste&lt;/a&gt; dumping into the oceans?&lt;/p&gt;&#xA;" OwnerUserId="22476" LastEditorUserId="16899" LastEditDate="2021-08-08T18:50:22.720" LastActivityDate="2021-09-18T20:12:24.857" Title="How does global-warming-triggered ice melting cause global sea levels to rise?" Tags="|climate-change|oceanography|glaciology|plastic|" AnswerCount="6" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22664" PostTypeId="2" ParentId="22663" CreationDate="2021-08-07T15:32:31.667" Score="43" Body="&lt;p&gt;Arctic ice, around the north pole &lt;strong&gt;floats on top of water&lt;/strong&gt;. When it melts it does not add to sea level rises and likewise for other ice &lt;strong&gt;on water&lt;/strong&gt;, as illustrated in &lt;a href=&quot;https://www.youtube.com/watch?v=Vers5VT4m8E&quot; rel=&quot;noreferrer&quot;&gt;this video&lt;/a&gt; and &lt;a href=&quot;https://www.youtube.com/watch?v=550ovNHCxAg&quot; rel=&quot;noreferrer&quot;&gt;this video&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Ice on land&lt;/strong&gt; is a different matter. Ice on Greenland, Antarctic land &amp;amp; glaciers around the world will add to sea level rise because any melt water will eventually end up in the oceans. It's like adding water to a partially filled glass of water.&lt;/p&gt;&#xA;&lt;p&gt;The thickness of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Greenland_ice_sheet&quot; rel=&quot;noreferrer&quot;&gt;Greenland Ice Sheet&lt;/a&gt; is more than 2 km and it is of the order of 2900 km long and 1000 km wide. The amount of ice in Greenland is 2,850,000 cubic kilometres. If this alone were to melt it would increase sea levels by 7 m. The island of Greenland cannot contain all the melt water and it will end up in the sea.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Antarctic_ice_sheet&quot; rel=&quot;noreferrer&quot;&gt;Antarctic ice sheet&lt;/a&gt; contains 26.5 million cubic kilometres.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-08-09T09:24:18.040" LastActivityDate="2021-08-09T09:24:18.040" CommentCount="13" ContentLicense="CC BY-SA 4.0" />
  <row Id="22665" PostTypeId="1" CreationDate="2021-08-07T15:44:46.290" Score="1" ViewCount="26" Body="&lt;p&gt;There is a 210 cm long soil column that has five layers of different soil types. The topsoil layer of 15 cm has a moisture sensor in the middle. The second and third layers are of 95 and 80 cm of length and only have sensors on top and at the bottom, respectively. There are two 10-cm-long layers of sand and gravel at the end (for drainage).&lt;/p&gt;&#xA;&lt;p&gt;So my assumption is that this network of sensors cannot give me a good estimate of the whole column water storage.&lt;/p&gt;&#xA;&lt;p&gt;To be more specific, the (30-min) sensors are at these depths: 7.5 cm, 22.5 cm, 175 cm, and 185 cm.&lt;/p&gt;&#xA;&lt;p&gt;A lysimeter at the bottom of last layer (beneath 20 cm of sand and gravel drainage layers) collects the percolation on an hourly basis. Also, runoff is being collected (though insignificant values, 4 mm for 2 years for instance).&lt;/p&gt;&#xA;&lt;p&gt;The vegetation is natural growing grass. With 3 months of snow covered ground annually.&lt;/p&gt;&#xA;&lt;p&gt;How would you suggest I estimate ETP (daily or hourly) for this column and how confident I should be about its accuracy?&lt;/p&gt;&#xA;" OwnerUserId="20807" LastEditorUserId="20807" LastEditDate="2021-08-07T16:44:15.167" LastActivityDate="2021-08-07T16:44:15.167" Title="How to estimate evapotranspiration using moisture sensors?" Tags="|hydrology|hydrogeology|evaporation|field-measurements|soil-moisture|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22666" PostTypeId="2" ParentId="22663" CreationDate="2021-08-07T15:48:06.020" Score="14" Body="&lt;p&gt;&lt;strong&gt;Because a lot of that ice is currently sitting on land.&lt;/strong&gt; When it melts, it will go into the ocean. From the National Snow and Ice Data Center Page (NSIDC), &lt;a href=&quot;https://nsidc.org/cryosphere/glaciers/quickfacts.html&quot; rel=&quot;noreferrer&quot;&gt;Facts about glaciers&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Presently, 10 percent of land area on Earth is covered with glacial ice, including glaciers, ice caps, and the ice sheets of Greenland and Antarctica. Glacierized areas cover over 15 million square kilometers (5.8 million square miles).&lt;/p&gt;&#xA;&lt;p&gt;Glaciers store about 69 percent of the world's fresh water.&lt;/p&gt;&#xA;&lt;p&gt;If all land ice melted, sea level would rise approximately 70 meters (230 feet) worldwide.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Also, just because melting sea ice doesn't directly contribute to rising sea levels, doesn't mean it isn't still a factor. From another NSIDC article, &lt;a href=&quot;https://nsidc.org/cryosphere/icelights/arctic-sea-ice-impacts&quot; rel=&quot;noreferrer&quot;&gt;What are the impacts of Arctic sea ice loss?&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Sea ice loss contributes to Arctic amplification&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Light-colored surfaces, like sea ice, have high albedo, meaning they reflect most of the sunlight that reaches them. Dark surfaces, like the surrounding ocean water, have low albedo.&lt;/p&gt;&#xA;&lt;p&gt;At the height of summer, when the Sun shines relentlessly on the Arctic Ocean, exposed ocean water absorbs nine times as much solar radiation, if not more, than sea ice does. Before ice can form again in the fall, the ocean must release the absorbed heat into the atmosphere. The loss of sea ice warms the Arctic, contributing to a phenomenon known as “Arctic amplification” where the Arctic warms at a faster rate than lower latitudes. [...]&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Does sea ice loss raise sea levels?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Just as sea ice absorbs wave energy and reduces wave action along shorelines, sea ice reduces wave action on ice, namely ice shelves (thick slabs of ice attached to coastlines that float over the ocean surface) and water-terminating glaciers. Increased wave action caused by sea ice retreat can flex and bend these ice bodies, increasing the possibility of retreat. Glaciers that have lost their ice fronts tend to flow faster, and because this process introduces a body of ice into the ocean that was not there previously, it raises sea level.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7741" LastActivityDate="2021-08-07T15:48:06.020" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22667" PostTypeId="1" CreationDate="2021-08-07T20:18:56.287" Score="3" ViewCount="67" Body="&lt;p&gt;What are the features of terrestrial lithographic/clastic sediment that indicate it was deposited into an oceanic as opposed to a terrestrial (e.g. fluvial or lacustrine) environment?  How to tell whether a given siltstone bed was deposited in either environment?&lt;/p&gt;&#xA;" OwnerUserId="11172" LastEditorUserId="2470" LastEditDate="2021-08-08T17:18:03.233" LastActivityDate="2021-08-10T14:26:26.543" Title="How to tell whether sediment was laid in ocean or on land" Tags="|sedimentology|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22668" PostTypeId="2" ParentId="9669" CreationDate="2021-08-08T12:26:40.270" Score="1" Body="&lt;p&gt;I highly doubt there's anything at all which would fulfil the criteria you're looking for due to the huge spectral range involved and an overlap between the two emission spectra.&lt;/p&gt;&#xA;&lt;p&gt;You'd need something which doesn't absorb anything between 0.2 µm and 70 µm.&lt;/p&gt;&#xA;&lt;p&gt;Alternatively you'd need something with two absorption bands of equal spread and magnitude sitting on equivalent intensity points of the two emission curves, but even then both emission curves are moving targets; the Earth's due to temperature changes and the Sun's due to various solar phenomena that effect the emission strength at specific wavelengths.&lt;/p&gt;&#xA;" OwnerUserId="23199" LastEditorUserId="2470" LastEditDate="2021-08-08T17:16:26.597" LastActivityDate="2021-08-08T17:16:26.597" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22670" PostTypeId="2" ParentId="8129" CreationDate="2021-08-08T15:17:53.603" Score="4" Body="&lt;p&gt;The mantle itself is solid, and melting only happens under special conditions like &lt;a href=&quot;https://en.wikipedia.org/wiki/Subduction_zone#Structure_of_subduction_zones&quot; rel=&quot;nofollow noreferrer&quot;&gt;in subduction zones&lt;/a&gt;. This molten fraction is the magma, which can then rise closer to the surface and into the lithosphere, creating pockets of magma that can be penetrated by not too deep drilling.&lt;/p&gt;&#xA;&lt;p&gt;A part of OP's question is whether, if we hit magma while drilling a hole, this magma would rise and erupt resulting in a volcano. The answer is &amp;quot;not necessarily&amp;quot;. Some kinds of magma are relatively tame and don't have too much trapped gas in them.&lt;/p&gt;&#xA;&lt;p&gt;There have been several encounters of magma while drilling. One of them (the first time) was &lt;a href=&quot;https://phys.org/news/2008-12-magma-situ.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;on the Big Island of Hawaii&lt;/a&gt;. Here's what the result was:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Workers at Ormat, one of the world's largest geothermal producers, discovered the magma in October 2005 when they hit a chamber of the magma about a mile and a half down while drilling an injection well.The substance quickly rose about 20 feet up into the drill hole before becoming glasslike as it cooled. Ormat workers redrilled the area several times, with the same result.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.nature.com/articles/news.2008.1317&quot; rel=&quot;nofollow noreferrer&quot;&gt;article in &lt;em&gt;Nature&lt;/em&gt;&lt;/a&gt; cites the magma chamber depth of 2.5 km, so it's not really deep, and quite far from the mantle. But this already gives us some understanding of behavior of some kinds of magma.&lt;/p&gt;&#xA;" OwnerUserId="12360" LastEditorUserId="12360" LastEditDate="2021-08-08T17:09:21.193" LastActivityDate="2021-08-08T17:09:21.193" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22671" PostTypeId="2" ParentId="22663" CreationDate="2021-08-09T08:11:05.030" Score="4" Body="&lt;p&gt;Loss of ice mass floating in oceans has negligible contribution to sea level rise. Loss of ice mass over land &lt;em&gt;does&lt;/em&gt; contribute to sea level rise.&lt;/p&gt;&#xA;&lt;p&gt;It is the net balance (the difference) between flow of ice and meltwater into the oceans and the amount of snowfall in the catchment that determines the overall change to a glacier's ice mass and &lt;em&gt;that&lt;/em&gt; determines if or how much a glacier's ice contributes to sea level rise.&lt;/p&gt;&#xA;&lt;p&gt;Most glaciers, ice caps and ice sheets in the world are currently losing ice mass.&lt;/p&gt;&#xA;&lt;p&gt;Picture of glacial ice entering ocean - contributing to ocean volume at that point, to melt later as floating ice -&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JHTf4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JHTf4.png&quot; alt=&quot;glacial ice entering ocean&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="18145" LastEditDate="2021-08-10T20:41:24.273" LastActivityDate="2021-08-10T20:41:24.273" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22672" PostTypeId="2" ParentId="22663" CreationDate="2021-08-09T11:04:57.903" Score="3" Body="&lt;p&gt;Your question mixes a few independent issues. Two of the statements are undisputed:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Yes, melt water has a smaller volume than the ice from which it comes. But obviously, that (smaller) volume of melt water still adds to the sea water and hence lets sea levels rise if the melted ice was on land before.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Melting ice that is swimming does indeed not contribute much to the sea level rise because its pressure displaces almost as much water as it will add to the sea when it is melted.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The conclusions you draw seem muddled, but here is a take on them:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The question whether the land ice comes from outer space is irrelevant with respect to future sea level rise: It would be the same, no matter where it comes from. The question is only interesting with respect to the past: If the current land ice is from Earth, then the sea level at times without glacial ice must have been correspondingly higher because the sea is the main depot of water on Earth. Indeed, the sea level &lt;a href=&quot;https://en.wikipedia.org/wiki/Past_sea_level&quot; rel=&quot;nofollow noreferrer&quot;&gt;has changed hundreds of meters&lt;/a&gt;, while glacial ice accumulated or melted.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;For what it's worth, current research indicates that a substantial fraction of Earth's water (and hence of the glacial ice) &lt;a href=&quot;https://en.wikipedia.org/wiki/Origin_of_water_on_Earth#Asteroids&quot; rel=&quot;nofollow noreferrer&quot;&gt;may be from outer space&lt;/a&gt;&lt;sup&gt;1&lt;/sup&gt; but as I said, it would raise sea levels no more and no less than &amp;quot;domestic&amp;quot; ice.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;sub&gt;&lt;sup&gt;1 &lt;/sup&gt;Well, Earth itself is from outer space, so to speak, because it is accumulated interplanetary matter from the accretion disk of the Sun. What the theory says is that the original composition of Earth's material did not have very much water in it because it was too hot for water to condense; and that oxidation of hydrogen over geological time frames does not suffice to produce the amounts we see today. Since many asteroids contain significant amounts of water they are one of the suggested sources for the water on Earth. So the suggestion is that water was &lt;em&gt;added later&lt;/em&gt; in Earth's geological history.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="5396" LastEditorUserId="5396" LastEditDate="2021-08-09T11:11:20.137" LastActivityDate="2021-08-09T11:11:20.137" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22673" PostTypeId="1" AcceptedAnswerId="22674" CreationDate="2021-08-09T12:27:51.887" Score="15" ViewCount="1081" Body="&lt;p&gt;While reading about sundials, I've seen maps depicting isogonic lines (those that connect points with the same magnetic declination values). Pray tell, what's happening in Antarctica? Why does it appear to have two South Poles?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=j7LqqvTmnVM&amp;amp;ab_channel=SteveJBlack&quot; rel=&quot;noreferrer&quot;&gt;https://www.youtube.com/watch?v=j7LqqvTmnVM&amp;amp;ab_channel=SteveJBlack&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mmvg7.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mmvg7.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="23206" LastActivityDate="2021-08-09T15:41:04.543" Title="What happens with the isogonic lines at the South Pole?" Tags="|geography|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22674" PostTypeId="2" ParentId="22673" CreationDate="2021-08-09T15:00:59.747" Score="14" Body="&lt;p&gt;An isogonic line is a point of constant magnetic declination, &lt;em&gt;i.e.&lt;/em&gt; a line where the angle between geographic north and magnetic north is some particular value.  (Or, equivalently, geographic south &amp;amp; magnetic south.)  You're asking about the points in the diagram at which several isogonic lines meet.  If we imagine taking a compass and walking around such a point, the &lt;em&gt;difference&lt;/em&gt; between geographic south and magnetic south would change rapidly as we cross many different isogonic lines, each with its own declination.&lt;/p&gt;&#xA;&lt;p&gt;One of the points on your map (the lower right one) is the Magnetic South Pole.  If we imagine walking in a circle this point, our compass would always point towards the center of the circle, and so magnetic south would be changing rapidly.  However, the direction of geographic south would stay pretty much the same so long as we didn't walk in too big of a circle.  Thus, at this point the difference between geographic south and magnetic south changes rapidly because the direction of &lt;em&gt;magnetic south&lt;/em&gt; changes rapidly.&lt;/p&gt;&#xA;&lt;p&gt;The other point on your map is the Geographic South Pole.  If we imagine walking in a circle about this point, our compass would always point pretty much in the same direction (towards the Magnetic South Pole.)  However, the direction of geographic south would change rapidly as we walked around the south pole. Thus, at this point the difference between geographic south and magnetic south changes rapidly because the direction of &lt;em&gt;geographic south&lt;/em&gt; changes rapidly.&lt;/p&gt;&#xA;&lt;p&gt;Note that &lt;a href=&quot;https://maps.ngdc.noaa.gov/viewers/historical_declination/&quot; rel=&quot;noreferrer&quot;&gt;the same thing happens in the Arctic Ocean&lt;/a&gt; as well.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZP4rZ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZP4rZ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4837" LastEditorUserId="4837" LastEditDate="2021-08-09T15:41:04.543" LastActivityDate="2021-08-09T15:41:04.543" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22675" PostTypeId="1" AcceptedAnswerId="22676" CreationDate="2021-08-09T17:58:08.230" Score="1" ViewCount="280" Body="&lt;p&gt;Can it be that our air will be unbreathable in a few years due to CO&lt;sub&gt;2&lt;/sub&gt; emission? I think I may suffer from global warming anxiety and I accuse CO&lt;sub&gt;2&lt;/sub&gt; for my shortness of breath. Is it rational?&lt;/p&gt;&#xA;" OwnerUserId="23210" LastEditorUserId="2470" LastEditDate="2021-08-10T15:49:51.053" LastActivityDate="2021-08-10T17:01:41.700" Title="Can we run out of air because of global warming?" Tags="|climate-change|co2|" AnswerCount="2" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22676" PostTypeId="2" ParentId="22675" CreationDate="2021-08-09T18:32:14.473" Score="9" Body="&lt;p&gt;No, you can't blame the &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; concentration &lt;em&gt;per se&lt;/em&gt; for your shortness of breath. From the &lt;a href=&quot;https://www.health.state.mn.us/communities/environment/air/toxins/co2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Minnesota (U.S.) Department of Health&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The outdoor concentration of carbon dioxide is about 400 parts per million (ppm) or higher in areas with high traffic or industrial activity. [...] Carbon dioxide concentrations indoors can vary from several hundred ppm to over 1000 ppm in areas with many occupants present for an extended period of time and where outdoor air ventilation is limited. [...]&lt;/p&gt;&#xA;&lt;p&gt;Carbon dioxide is not generally found at hazardous levels in indoor environments. The [Minnesota Department of Labor and Industry] has set workplace safety standards of 10,000 ppm for an 8-hour period and 30,000 ppm for a 15 minute period.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In a worst case scenario (energy consumption growing and being met 100% with fossil fuels), the U.S. National Oceanographic and Atmospheric Administration &lt;a href=&quot;https://www.climate.gov/news-features/understanding-climate/climate-change-atmospheric-carbon-dioxide&quot; rel=&quot;nofollow noreferrer&quot;&gt;projects&lt;/a&gt; a peak of 900 ppm in 2100 -- still less than the indoor concentration in many places today.&lt;/p&gt;&#xA;&lt;p&gt;However, there are several related effects of climate change that you could blame for your shortness of breath:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.c2es.org/content/wildfires-and-climate-change/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Drought which leads to wild fires&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.lung.org/clean-air/outdoors/what-makes-air-unhealthy/electric-utilities&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pollution from power plants&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.blf.org.uk/support-for-you/hot-weather&quot; rel=&quot;nofollow noreferrer&quot;&gt;Higher air temperatures&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Psychological_impact_of_climate_change#Eco-anxiety&quot; rel=&quot;nofollow noreferrer&quot;&gt;Eco-anxiety&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="7741" LastEditorUserId="7741" LastEditDate="2021-08-10T16:22:23.007" LastActivityDate="2021-08-10T16:22:23.007" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22677" PostTypeId="2" ParentId="22663" CreationDate="2021-08-09T22:40:29.407" Score="1" Body="&lt;p&gt;Thermal expansion of the ocean is responsible for about half the sea level rise:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;First, warmer water expands, and this &amp;quot;thermal expansion&amp;quot; of the ocean has contributed about half of the 2.8 inches (7 centimeters) of global mean sea level rise we've seen over the last 25 years, Nerem said. Second, melting land ice flows into the ocean, also increasing sea level across the globe.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;See: &lt;a href=&quot;https://climate.nasa.gov/news/2680/new-study-finds-sea-level-rise-accelerating/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://climate.nasa.gov/news/2680/new-study-finds-sea-level-rise-accelerating/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="23213" LastActivityDate="2021-08-09T22:40:29.407" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22678" PostTypeId="2" ParentId="8129" CreationDate="2021-08-09T23:44:46.310" Score="1" Body="&lt;p&gt;Actually we can answer the question experimentally because &lt;a href=&quot;https://en.wikipedia.org/wiki/Upper_mantle_body&quot; rel=&quot;nofollow noreferrer&quot;&gt;the upper mantle is exposed in some places, such as ocean floors&lt;/a&gt;. Such exposures are not exceptionally volcanic by any means. Instead their main property is the mafic/ultramafic minerals that make up mantle rock weather quickly upon exposure to the atmosphere. A mantle outcropping will be more likely covered with rust (formed from the oxidation of the iron-bearing components of the minerals) than with lava.&lt;/p&gt;&#xA;&lt;p&gt;Photos of mafic rock weathering are shown below from northwestern Russia [&lt;a href=&quot;https://doi.org/10.1016/j.chemgeo.2018.12.033&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;]; weathering of exposed mantle rock, also mafic, would likely appear similar.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/SdXRD.jpg&quot; alt=&quot;Weathering of mafic rock in northwest Russia[1]&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;1.&#xA;Ekaterina V. Vasyukova, Priscia Oliva, Jerome Viers, Francois Martinal, Bernard Dupré, Oleg S.Pokrovsky. &amp;quot;Chemical weathering of mafic rocks in boreal subarctic environment (northwest Russia) under influence of glacial moraine deposits&amp;quot;, &lt;em&gt;Chemical Geology&lt;/em&gt; &lt;strong&gt;509&lt;/strong&gt; (30 March 2019), 115-133. &lt;a href=&quot;https://doi.org/10.1016/j.chemgeo.2018.12.033&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/j.chemgeo.2018.12.033&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="2470" LastEditDate="2021-08-27T06:55:54.347" LastActivityDate="2021-08-27T06:55:54.347" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22679" PostTypeId="2" ParentId="22663" CreationDate="2021-08-10T02:09:12.810" Score="1" Body="&lt;p&gt;A few of us here have given eminently reasonable answers already, but I think I know where your confusion comes from. The argument &amp;quot;ice is less dense than water hence it must result in less volume if they melt in water&amp;quot; only works if the ice you are talking about is &lt;strong&gt;completely submerged&lt;/strong&gt; in water. Recall the images of icebergs you've seen -- none is completely submerged in water.&lt;/p&gt;&#xA;&lt;p&gt;Of course, the argument being flawed doesn't mean the conclusion cannot happen to be correct. So does the water level increase, decrease or remain the same, if a floating iceberg melts?&lt;/p&gt;&#xA;&lt;p&gt;This question requires some physics of the buoyancy force. Since the buoyancy force provided by water to the iceberg is equal to the force of gravity on the displaced water, F_buoyant=ρVg, where V is the displaced volume of water, and also equal to the force of gravity on the iceberg since it's floating. This means, the mass of the displaced water when the iceberg is floating, should be exactly the same as the mass of the iceberg itself. It follows that if icebergs were the same density as the sea water they float on, then the water level would remain exactly the same. You can verify this by experimenting with a glass of water and floating ice cubes. But salty water is of higher density than fresh water, which is what icebergs become when they melt. Hence the water level would increase if icebergs melt. This can also be empirically verified.&lt;/p&gt;&#xA;&lt;p&gt;This however is only one of the reasons that the water level rises. As many others have pointed out, much of the glacier is not floating on water -- they are on land. Their melting and pouring into the ocean would obviously increase the water level. Thermal expansion goes the same direction.&lt;/p&gt;&#xA;" OwnerUserId="23215" LastActivityDate="2021-08-10T02:09:12.810" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22680" PostTypeId="1" AcceptedAnswerId="22682" CreationDate="2021-08-10T07:52:46.210" Score="6" ViewCount="122" Body="&lt;p&gt;BBC says that the latest IPCC report says methane is responsible for 0.3°C out of 1.1°C of all cumulative warming since pre-industrial times.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;According to the IPCC, around 0.3C of the 1.1C that the world has already warmed by comes from methane.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;em&gt;(from &lt;a href=&quot;https://www.bbc.com/news/science-environment-58138714&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;)&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;But the thing is I opened the &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/sites/2/2019/06/SR15_Full_Report_High_Res.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;report&lt;/a&gt;, Ctrl+F'ed &amp;quot;0.3&amp;quot; and &amp;quot;methane&amp;quot;, and didn't find that. Is it true that methane is responsible for nearly one-third of all warming? Did I miss something in the text?&lt;/p&gt;&#xA;&lt;p&gt;UPD: &lt;a href=&quot;https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Full_Report.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;This&lt;/a&gt; is THE report, actually. I didn't find it there too, though (I searched for &amp;quot;0.3°C&amp;quot;).&lt;/p&gt;&#xA;&lt;p&gt;UPD 2: @Deditos found something interesting on page 7.183 (1797)&lt;/p&gt;&#xA;" OwnerUserId="22632" LastEditorUserId="22632" LastEditDate="2021-08-10T21:45:51.317" LastActivityDate="2021-08-10T21:45:51.317" Title="Is it true that methane is responsible for nearly one-third of all warming?" Tags="|climate-change|greenhouse-gases|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22682" PostTypeId="2" ParentId="22680" CreationDate="2021-08-10T12:48:38.620" Score="6" Body="&lt;p&gt;Yes, this is broadly true.  I haven't looked into much of the report yet, but I suspect that the BBC are referring to Fig 7.7 for an estimate of the observed warming attributed to changes in methane concentration.  The figure has 0.28 °C as the best estimate, which they've rounded (or had quoted to them in a briefing) as 0.3 °C:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Nx5Qg.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Nx5Qg.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The slight wrinkle is that estimate is for 2019 relative to 1750 and a total warming of 1.27 °C, whereas the quoted 1.1 °C total warming is probably the observed 2010-19 relative to 1850-1900 value (see SPM A.1.2 or A.1.3).  It's possible that the BBC are mashing together some incompatible estimates here or, as I say, they may have been briefed with the best bottom line to quote.  Note that the Summary for Policymakers (SPM) has another figure, SPM.2, that gives a best estimate of the methane contribution of 0.5 °C relative to the appropriate decades:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Sl7pS.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Sl7pS.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As I say, I haven't looked into all the nuances of these different estimates yet but, yes, the contribution to total warming attributed to methane is comfortably several tenths of a °C.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2021-08-10T12:48:38.620" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22683" PostTypeId="2" ParentId="22667" CreationDate="2021-08-10T14:26:26.543" Score="1" Body="&lt;p&gt;Although now rather dated,  &lt;a href=&quot;https://pubs.usgs.gov/bul/1080/report.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS Bulletin 1080&lt;/a&gt; has a useful discussion of various lines of evidence that can be used to distinguish lacustrine from marine deposits. Looking at purely physical characteristics it is often assumed that spatially extensive, fine grained, laminated deposits are suggestive of the low energy, and potentially seasonally varying, environment of a lake, with oceanic environments having greater energy, so less uniformity. It is easy, however, to see that there are may exceptions to this simple classification.&lt;/p&gt;&#xA;&lt;p&gt;Fossil evidence can be a conclusive identifying factor, but isn't always available. The presence of evaporite minerals is suggestive of closed lacustrine environments, but obviously coastal sabkha evaporites are common.&lt;/p&gt;&#xA;&lt;p&gt;Carbon/Sulphur ratio have been suggested as an indicator, with pyrite more common in marine sediments.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2021-08-10T14:26:26.543" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22684" PostTypeId="2" ParentId="22675" CreationDate="2021-08-10T16:58:31.783" Score="1" Body="&lt;p&gt;As far as displacement of oxygen, CO&lt;sub&gt;2&lt;/sub&gt; is not even close to a concern. Air is already close to 80% nitrogen, and about 20% oxygen. CO&lt;sub&gt;2&lt;/sub&gt; is only about 0.04% of the atmosphere, so even if  CO&lt;sub&gt;2&lt;/sub&gt; were multiplied by a factor of 10,000, the concentration of oxygen would decrease by only about 4%.&lt;/p&gt;&#xA;&lt;p&gt;However, the human body relies primarily on the presence of CO&lt;sub&gt;2&lt;/sub&gt;, rather the absence of oxygen, to detect when it's not getting sufficient respiration. As little as one order of magnitude (i.e. multiplying by ten) can be enough for there to be health effects of CO&lt;sub&gt;2&lt;/sub&gt;, but only the most pessimistic projections have us doubling CO&lt;sub&gt;2&lt;/sub&gt; concentration in the next hundred years.&lt;/p&gt;&#xA;" OwnerUserId="11501" LastEditorUserId="2470" LastEditDate="2021-08-10T17:01:41.700" LastActivityDate="2021-08-10T17:01:41.700" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22685" PostTypeId="1" CreationDate="2021-08-10T17:24:31.417" Score="4" ViewCount="49" Body="&lt;p&gt;Table 6.2 on p. 10 &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/03/TAR-06.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; contrasts the logarithmic radiative forcing of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO_2}$&lt;/span&gt; with the square-root forcing of &lt;span class=&quot;math-container&quot;&gt;$\ce{CH_4}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\ce{N_2O}$&lt;/span&gt;, and the linear forcing of CFCs. Are there similar results for the cooling effects of species such as &lt;span class=&quot;math-container&quot;&gt;$\ce{SO_2}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\ce{H_2S}$&lt;/span&gt;? (&lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/03/TAR-05.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;The previous chapter&lt;/a&gt; discusses aerosols, but doesn't appear to contain a similar table.) Is there any theoretical basis for these specific relationships in either case?&lt;/p&gt;&#xA;&lt;p&gt;It has been estimated stratospheric aerosol injection of &lt;span class=&quot;math-container&quot;&gt;$\ce{SO_2}$&lt;/span&gt; would require only &lt;span class=&quot;math-container&quot;&gt;$\sim1\ce{Mt}$&lt;/span&gt; to mitigate the warming effects on Earth of &lt;span class=&quot;math-container&quot;&gt;$\sim1\ce{Tt}$&lt;/span&gt; of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO_2}$&lt;/span&gt; (atmospheric half-lives aside), suggesting the relationship is closer to linear than logarithmic. But that's just my guess, plus it doesn't preclude e.g. a square-root relationship.&lt;/p&gt;&#xA;" OwnerUserId="7803" LastEditorUserId="7803" LastEditDate="2022-02-27T15:45:35.103" LastActivityDate="2022-02-27T15:45:35.103" Title="How do radiative forcing and anti-forcing scale with concentration?" Tags="|climate-change|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="22686" PostTypeId="2" ParentId="12837" CreationDate="2021-08-10T17:40:47.073" Score="1" Body="&lt;p&gt;When the density of atmospheric carbon increases, so too does the amount of water vapor in the atmosphere.&#xA;What is being overlooked is the effect that the water vapor has on the sunlight shining through it, as it serves to intensify it, much like a magnifying glass.&lt;/p&gt;&#xA;" OwnerUserId="23218" LastActivityDate="2021-08-10T17:40:47.073" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22687" PostTypeId="2" ParentId="810" CreationDate="2021-08-11T10:22:05.027" Score="-3" Body="&lt;p&gt;The reality is that we don’t know how reliable proxies are.  All of them have shown deficiencies.  Corals have shown they don’t fix &lt;sup&gt;18&lt;/sup&gt;O like a time capsule, ice cores show that they’re not static (things migrate through the ice) and tree rings show a cooling trend in the late 20th century.  Aggregating a bunch of proxies on the assumption that these errors cancel is unproven and a huge leap of faith.  Anyone who claims proxies can detect global temperature to anything near what a thermometer can detect is either crazy or lying to you.  I wish it weren’t so, but that’s reality. There are too many unknown errors and since we don’t actually have a record of temperature prior to 1850, we have nothing to compare it against.&lt;/p&gt;&#xA;" OwnerUserId="23226" LastEditorUserId="2470" LastEditDate="2021-08-11T10:47:54.100" LastActivityDate="2021-08-11T10:47:54.100" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22689" PostTypeId="1" CreationDate="2021-08-12T14:21:34.973" Score="2" ViewCount="87" Body="&lt;p&gt;I wanted to know : what if someone pulled a really strong vacuum and prevented any air to enter. Would the earth be destroyed or nothing much would happen? I am not talking about the people and other living organisms, but what would happen to the planet itself.&lt;/p&gt;&#xA;&lt;p&gt;Thanks in advance.&#xA;(Sorry if off-topic)&lt;/p&gt;&#xA;" OwnerUserId="23237" LastEditorUserId="22648" LastEditDate="2021-08-13T05:48:54.543" LastActivityDate="2021-08-13T05:48:54.543" Title="What would happen to the earth if we removed nearly all of the air?" Tags="|earth-system|air|" AnswerCount="1" CommentCount="6" ClosedDate="2021-08-13T12:10:27.203" ContentLicense="CC BY-SA 4.0" />
  <row Id="22690" PostTypeId="1" CreationDate="2021-08-12T17:25:08.210" Score="3" ViewCount="176" Body="&lt;p&gt;I'm very interested in Russian history, and this led me the other day to look at a beautiful painting of the famous Vladimir Highway. The painting is famous in its own right, and is said to express deep truths about the Russian soul. It made me ask myself: &lt;strong&gt;Is Russia flatter than the UK?&lt;/strong&gt; (I'm English.)&lt;/p&gt;&#xA;&lt;p&gt;The question seems fairly straightforward, but I can't see any straightforward way of answering it. On the one hand, Russia's highest peak, Mount Elbrus, is some 5642 m above sea level, and thus over four times higher than Ben Nevis, the UK's highest point. On the other hand, Russia's famous lack of defensible terrain has led to Moscow being besieged and/or razed numerous times, whereas the moorland which constitutes most of the border between England and Scotland hindered the English from ever subjugating their northern neighbours militarily.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Average elevation&lt;/strong&gt; seems like a sensible statistic to look at - until one remembers countries like Botswana, which is located on one large plateau, and which thus has a high average elevation, and yet (I'm told) is rather flat.&lt;/p&gt;&#xA;&lt;p&gt;I suppose one would want something like an &lt;strong&gt;interquartile range&lt;/strong&gt; of elevations. But how would one pick, say, 100 elevations in the country in question, from which to pick the 25th and the 75th highest?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Is there already one single, generally accepted statistic for measuring how flat or hilly a given country, county, parish, etc is?&lt;/strong&gt; If so, how do Russia and the UK compare to other countries?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/x1ESe.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/x1ESe.jpg&quot; alt=&quot;vladimir_highway&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="23238" LastActivityDate="2021-08-12T20:44:57.140" Title="Is there any single, generally accepted statistic describing the flatness of a given territory?" Tags="|geography|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22691" PostTypeId="2" ParentId="22690" CreationDate="2021-08-12T20:44:57.140" Score="2" Body="&lt;p&gt;It's actually more complex than you would think because landscapes are approximately &lt;a href=&quot;https://en.wikipedia.org/wiki/Fractal_landscape&quot; rel=&quot;nofollow noreferrer&quot;&gt;fractal surfaces&lt;/a&gt;. An analogue is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Coastline_paradox&quot; rel=&quot;nofollow noreferrer&quot;&gt;coastline paradox&lt;/a&gt;. Basically, the problem is to measure the length of a coastline. Simple, right? But, as it turns out, it's totally dependent on the resolution used. The smaller your measuring stick, the more little inlets you measure, and the perimeter grows to infinity in the limit of small measuring sticks as you measure around every little sand grain and rock. Lines like these are, statistically, fractals, in the sense that, looking at smaller and smaller scales you will see about the same amount of looping back on itself. These are common in nature; a better example (because it is a fractal to much smaller scales) is a cloud.&lt;/p&gt;&#xA;&lt;p&gt;Similarly, there is no preferred scale when looking at a landscape, because large mountains look approximately like hills (hills in the same region-the statistics are not the same around the world). The way to measure the roughness of these surfaces is by their &lt;a href=&quot;https://en.wikipedia.org/wiki/Hausdorff_dimension&quot; rel=&quot;nofollow noreferrer&quot;&gt;fractal or Hausdorff dimension.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Of course, however, all of these things are not perfect fractals and are really only fractals for a certain size range. Big mountains look like little mountains, but rocks under your shoe look different. And in my explanation above, it's questionable to compare the sand grains to the coast as you would see it on a map. And, finally, I don't have expertise regarding what actual geographers use as their measure of roughness, but they certainly have to contend with fractal statistics.&lt;/p&gt;&#xA;" OwnerUserId="23246" LastActivityDate="2021-08-12T20:44:57.140" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22692" PostTypeId="2" ParentId="22689" CreationDate="2021-08-12T23:15:15.803" Score="3" Body="&lt;p&gt;We already have a model of an atmosphere-stripped Earth at hand, it's called &lt;strong&gt;Mars&lt;/strong&gt;. Essentially, the loss of air on Mars meant more things didn't happen any longer than did happen. Erosion and corrosion processes caused by the air -- and by fine particles carried by the air-- largely stopped with the loss of a thick atmosphere, effectively freezing mineral deposits. As a result, explorations of the Martian surface may be used to identify areas that were exposed versus those that were protected (as if by a body of water).&lt;/p&gt;&#xA;&lt;p&gt;For example, we may look at &lt;a href=&quot;https://space.stackexchange.com/a/40874/28871&quot;&gt;this answer&lt;/a&gt; at Space Exploration Stack Exchange, which summarizes the minerals found at various depths in the Gale Crater on Mars. Note especially the relative concentrations of mafic rock and iron oxides; the former is converted to the latter upon exposure to an oxidizing atmosphere. We see that the upper reaches, which likely would have been exposed when Mars had a thick atmosphere, still have the iron oxides produced by oxidation of the mafic rock, whereas the mafic matter below which might have been protected by a lake has remained largely intact.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="543" LastEditDate="2021-08-13T01:22:19.437" LastActivityDate="2021-08-13T01:22:19.437" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22693" PostTypeId="1" CreationDate="2021-08-13T09:18:21.617" Score="1" ViewCount="34" Body="&lt;p&gt;in &lt;code&gt;Thornthwaite &amp;amp; Mather (1954) Soil Water Balance Approach&lt;/code&gt;&#xA;The soil moisture output is generated for the whole soil profile, i.e whatever depth we take for the model eg: &lt;code&gt;from surface to 60 cm&lt;/code&gt;  or &lt;code&gt; from surface to 100 cm&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;The basic approach is,&#xA;for any time scale,&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;if precipitation is more than the potential evapotranspiration then, the net/balance moisture is added to the previous/initial moisture of previous time step (day/month etc.)&lt;/li&gt;&#xA;&lt;li&gt;if potential evapotranspiration exceeds precipitation or there is no precipitation at all, then soil moisture for the current time step will decrease exponentially from the soil moisture available in the previous time step following the empirical equation mentioned in the flowchart.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;The reference publications are available at:- &lt;a href=&quot;http://www.hydrology.bee.cornell.edu/BEE3710Handouts/TM2013.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;reference 1&lt;/a&gt;, &lt;a href=&quot;https://www.tandfonline.com/doi/abs/10.1623/hysj.49.1.131.53997&quot; rel=&quot;nofollow noreferrer&quot;&gt;reference 2&lt;/a&gt;, &lt;a href=&quot;https://eujournal.org/index.php/esj/article/view/8526&quot; rel=&quot;nofollow noreferrer&quot;&gt;reference 3&lt;/a&gt;, &lt;a href=&quot;https://link.springer.com/article/10.1007/s10661-019-7230-9&quot; rel=&quot;nofollow noreferrer&quot;&gt;reference 4&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IdBFQ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IdBFQ.png&quot; alt=&quot;Flowchart&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The output generated by the model follows the trend corresponding to precipitation, runoff and ET that happened during the subsequent time period.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/JgbsJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JgbsJ.png&quot; alt=&quot;SM out&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But is there any way to distribute this output into different layers,&lt;/p&gt;&#xA;&lt;p&gt;say, we run the model for 100 cm soil profile (surface to 100 cm soil depth), and got the output values at each day/month.&#xA;How can we distribute it to different layers say from 0-15, 15-30, 30-60, and 60-100cm.&lt;/p&gt;&#xA;&lt;p&gt;What I did here was, that I saturate the 1st layer (0-15cm), then sent the residual moisture to the bottom layers, then saturated the 2nd layer (15-30cm) and sent the residual moisture again to the layers below, and so on....&lt;/p&gt;&#xA;&lt;p&gt;but results are logically not right, the top layers always stay saturated and the bottom layers always remain dry.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/CWBc9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CWBc9.png&quot; alt=&quot;Layered SM&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;However the soil moisture from the top layers should deplete first, as the evapotranspirational losses from top layers will be more as compared to the bottom layers, and the moisture in the bottom layers should be more stable.&lt;/p&gt;&#xA;&lt;p&gt;another thing here is that Thornthwaite soil water balance model uses &lt;code&gt;available water capacity&lt;/code&gt; in its equations&#xA;i.e the water held in the soil between &lt;code&gt;field capacity&lt;/code&gt; and &lt;code&gt;permanent wilting point&lt;/code&gt;,&#xA;but the &lt;code&gt;saturation limit&lt;/code&gt; of soil is above &lt;code&gt;field capacity&lt;/code&gt;&#xA;so saturating the layer using &lt;code&gt;saturation limit&lt;/code&gt; in spite of &lt;code&gt;field capacity&lt;/code&gt; also does not seems ideal here.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;So how this soil moisture generated from Thornthwaite &amp;amp; Mather (1954) Soil Water Balance Model can be distributed into different layers.&lt;/strong&gt;&#xA;Suggestions will be highly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="23249" LastEditorUserId="23249" LastEditDate="2021-08-13T09:23:29.643" LastActivityDate="2021-08-13T09:23:29.643" Title="How to Distribute Soil moisture output of Thornthwaite and Mather (1954) Soil Water Balance Model into different layers?" Tags="|water|soil|climatology|soil-science|soil-moisture|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22694" PostTypeId="1" CreationDate="2021-08-13T15:39:58.990" Score="5" ViewCount="107" Body="&lt;p&gt;I am physics grad student working on a problem of making a statistical (neural network) prediction of the air pollution in a city. I am provided with hourly values for ca. a dozen meteo features of the city for the last ~20 years - temperature, humidity, wind speed, wind direction, PM10, O&lt;sub&gt;3&lt;/sub&gt;, SO&lt;sub&gt;2&lt;/sub&gt; concentrations a.o. What I've read is that the air pollution (especially in winter) often is present when a thermal inversion occurs, meaning when the temperature of the air above the city increases with altitude, instead of decreasing. Luckily enough, there are weather measuring stations in the city AND also one just outside the city at an altitude of 1350 m (the city itself has an altitude of ~600 m). This allows me to introduce another feature that might be useful - the difference in temperature at high and low altitude as a proxy for thermal inversion (&lt;span class=&quot;math-container&quot;&gt;$T_{proxy-inv} = T_{high} - T_{low}$&lt;/span&gt;).&lt;/p&gt;&#xA;&lt;p&gt;My question: what other meteorological features are affected when inversion occurs, so that I can use them as an additional proxy? Does the pressure change notably? Or maybe the wind speed is very low during an inversion? Does something else happen during thermal inversion?&#xA;Or can you point me towards another meteorological effect, besides inversion, that can influence air pollution? Tnx!&lt;/p&gt;&#xA;" OwnerUserId="20337" LastEditorUserId="2470" LastEditDate="2021-08-15T05:10:01.133" LastActivityDate="2021-08-15T05:10:01.133" Title="What meteorological features accompany/cause a thermal inversion?" Tags="|meteorology|weather-forecasting|air-pollution|inversion|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22697" PostTypeId="1" CreationDate="2021-08-14T04:14:33.230" Score="2" ViewCount="229" Body="&lt;h2&gt;Background&lt;/h2&gt;&#xA;&lt;p&gt;The Denali (Mount McKinley) is the third most prominent mountain on earth.&lt;/p&gt;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_mountain_peaks_by_prominence&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia&lt;/a&gt; It has a height of 6,191 meters, a prominence of 6,144 meters, and a &amp;quot;col&amp;quot; of 6,191 - 6,144 = 47 meters. Totally checks out!&lt;/p&gt;&#xA;&lt;p&gt;I assume the lowest point on the &amp;quot;mountain ridge&amp;quot; connecting the two peaks must be somewhere in the Panama Canal, or at least it cannot be higher than that. From what I found, the highest place in the Panama canal is Gatun Lake.&lt;/p&gt;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://en.wikipedia.org/wiki/Gatun_Lake&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia&lt;/a&gt;, Gatun Lake has a surface elevation of 26m. This is less than the 47 I found for the &amp;quot;col&amp;quot; between Denali and Aconcagua.&lt;/p&gt;&#xA;&lt;p&gt;So where do the 47m come from?&lt;/p&gt;&#xA;" OwnerUserId="23263" LastActivityDate="2024-02-03T04:12:06.590" Title="Lowest point between Denali and Aconcagua" Tags="|geography|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22698" PostTypeId="2" ParentId="15289" CreationDate="2021-08-14T14:07:36.290" Score="0" Body="&lt;p&gt;&lt;a href=&quot;https://www.sciencedaily.com/releases/2020/05/200521112619.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mysterious glowing coral reefs are fighting to recover&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A new study by the University of Southampton has revealed why some corals exhibit a dazzling colourful display, instead of turning white, when they suffer 'coral bleaching' -- a condition which can devastate reefs and is caused by ocean warming. The scientists behind the research think this phenomenon is a sign that corals are fighting to survive.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Many coral animals live in a fragile, mutually beneficial relationship, a 'symbiosis' with tiny algae embedded in their cells. The algae gain shelter, carbon dioxide and nutrients, while the corals receive photosynthetic products to fulfil their energy needs. If temperatures rise just 1?C above the usual summer maximum, this symbiosis breaks down; the algae are lost, the coral's white limestone skeleton shines through its transparent tissue and a damaging process known as 'coral bleaching' occurs.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="22798" LastActivityDate="2021-08-14T14:07:36.290" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22699" PostTypeId="1" CreationDate="2021-08-14T15:23:42.890" Score="2" ViewCount="414" Body="&lt;p&gt;The shallow water equations are:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;\begin{aligned}&#xA;&amp;amp;\frac{du}{dt} = -g\frac{\partial h}{\partial x} + fv\\&#xA;&amp;amp;\frac{dv}{dt} = -g\frac{\partial h}{\partial y} - fu\\&#xA;&amp;amp;\frac{dh}{dt} = -h(\frac{\partial u}{\partial x}+\frac{\partial v}{\partial y})&#xA;\end{aligned}&lt;/span&gt;&#xA;where h is the height (or depth) of the shallow water, &lt;span class=&quot;math-container&quot;&gt;$u$&lt;/span&gt; is the eastward velocity, &lt;span class=&quot;math-container&quot;&gt;$v$&lt;/span&gt; is the northward velocity, g is the acceleration of gravity and f is the coriolis parameter.&lt;/p&gt;&#xA;&lt;p&gt;my problem is how to linearize these equations. From the linearization theorem, I know that I should take&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{aligned}&#xA;&amp;amp;u = \overline{u} + u'\\&#xA;&amp;amp;v = \overline{v} + v'\\&#xA;&amp;amp;h = \overline{h} + h'&#xA;\end{aligned}&lt;/span&gt;&#xA;then take them into the original equations, but I just do not know how. From my understanding, take the equation of &lt;span class=&quot;math-container&quot;&gt;$h$&lt;/span&gt; as an example, the result should be&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\frac{\partial}{\partial t}(\overline{h} + h') + (\overline{u} + u')\frac{\partial}{\partial x}(\overline{h} + h') + (\overline{v} + v')\frac{\partial}{\partial y}(\overline{h} + h') = -(\overline{h} + h')(\frac{\partial \overline{u}}{\partial x} + \frac{\partial \overline{v}}{\partial y} + \frac{\partial u'}{\partial x} + \frac{\partial v'}{\partial y})&#xA;\end{equation}&lt;/span&gt;&#xA;by using the equation&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{aligned}&#xA;\frac{d\overline{h}}{dt} = -\overline{h}(\frac{\partial \overline{u}}{\partial x}+\frac{\partial \overline{v}}{\partial y})&#xA;\end{aligned}&lt;/span&gt;&#xA;and ignore the terms like &lt;span class=&quot;math-container&quot;&gt;$u'\frac{\partial h'}{\partial x}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$v'\frac{\partial h'}{\partial y}$&lt;/span&gt;, the result I obtained is&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\frac{\partial h'}{\partial t} + \overline{u}\frac{\partial h'}{\partial x} + \overline{v}\frac{\partial h'}{\partial y} = -\overline{h}(\frac{\partial u'}{\partial x} + \frac{\partial v'}{\partial y}) - h'(\frac{\partial \overline{u}}{\partial x} + \frac{\partial \overline{v}}{\partial y})&#xA;\end{equation}&lt;/span&gt;&#xA;but in my textbook, the result is just&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\frac{\partial h'}{\partial t}  = -\overline{h}(\frac{\partial u'}{\partial x} + \frac{\partial v'}{\partial y}) &#xA;\end{equation}&lt;/span&gt;&#xA;so I want to ask that where did I make a mistake? Actually, I got the same problem in the linearization of the equations of &lt;span class=&quot;math-container&quot;&gt;$u$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$v$&lt;/span&gt;.&lt;/p&gt;&#xA;" OwnerUserId="21802" LastActivityDate="2021-08-14T23:03:32.373" Title="How to linearize the shallow-water equations?" Tags="|meteorology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22700" PostTypeId="1" CreationDate="2021-08-14T22:24:30.147" Score="0" ViewCount="1078" Body="&lt;p&gt;Water pumped into a desert would evaporate and increase formation of clouds which would in turn increase the albedo of the Earth.  Would this help to cool the planet more efficiently than trying to capture carbon?&lt;/p&gt;&#xA;" OwnerUserId="23265" LastEditorUserId="6467" LastEditDate="2023-02-11T18:56:40.310" LastActivityDate="2023-02-11T18:56:40.310" Title="If ocean water was pumped into a desert would it help cool the planet?" Tags="|climate-change|geoengineering|carbon-capture|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="22701" PostTypeId="2" ParentId="22699" CreationDate="2021-08-14T23:03:32.373" Score="1" Body="&lt;p&gt;Well, I can see one thing. Note that you can rearrange the equation you derived to look like this: &lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial h'}{\partial t}+\bar{u}\frac{\partial h'}{\partial x}+\bar{v}\frac{\partial h'}{\partial y}+h'\frac{\partial \bar{u}}{\partial x}+h'\frac{\partial \bar{v}}{\partial y}=-\bar{h}\left(\frac{\partial u'}{\partial x}+\frac{\partial v'}{\partial y}\right)$$&lt;/span&gt;. Observe that the left hand side can be grouped together using the product rule. &lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial h'}{\partial t}+\frac{\partial \bar{u}h'}{\partial x}+\frac{\partial \bar{v}h'}{\partial y}=-\bar{h}\left(\frac{\partial u'}{\partial x}+\frac{\partial v'}{\partial y}\right)$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now there are a couple of assumptions that could be made (I don't have mine near me as I write this). I suggest you read what is in your textbook. It could be aomething along the lines of the anelastic assumption, it could be that there is no mean flow, etc. However, the assumption should yield &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial \bar{u}h'}{\partial x}+\frac{\partial \bar{v}h'}{\partial y}\approx0$&lt;/span&gt; or &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial \bar{u}h'}{\partial x}+\frac{\partial \bar{v}h'}{\partial y}=0$&lt;/span&gt;.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-08-14T23:03:32.373" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22702" PostTypeId="2" ParentId="22694" CreationDate="2021-08-14T23:32:24.617" Score="5" Body="&lt;p&gt;A thermal inversion is defined as when the temperature of the air increases with height. By default, there always exists an inversion at the tropopause due to the exothermal &lt;a href=&quot;https://en.wikipedia.org/wiki/Ozone%E2%80%93oxygen_cycle&quot; rel=&quot;noreferrer&quot;&gt;Chapman cycle&lt;/a&gt;. But let's ignore that, given the context of the question.&lt;/p&gt;&#xA;&lt;p&gt;Let's take a look at the thermodynamic equation and see how the stability changes. The diagnostic equation for the &lt;a href=&quot;https://en.wikipedia.org/wiki/Potential_temperature&quot; rel=&quot;noreferrer&quot;&gt;dry adiabatic potential temperature&lt;/a&gt; (&lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt;) is &lt;span class=&quot;math-container&quot;&gt;$$\frac{D \theta}{Dt}=\frac{\partial \theta}{\partial t}+u\frac{\partial \theta}{\partial x}+v\frac{\partial \theta}{\partial y}+w\frac{\partial \theta}{\partial z}=Q$$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$u$&lt;/span&gt;,&lt;span class=&quot;math-container&quot;&gt;$v$&lt;/span&gt;,and &lt;span class=&quot;math-container&quot;&gt;$w$&lt;/span&gt; are the zonal, meridional, and vertical components of the wind vector, and &lt;span class=&quot;math-container&quot;&gt;$Q$&lt;/span&gt; is the diabatic heating rate. Taking the vertical dervative of the above equation is &lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial}{\partial t}\frac{\partial \theta}{\partial z}+u\frac{\partial}{\partial x}\frac{\partial \theta}{\partial z}+v\frac{\partial}{\partial y}\frac{\partial \theta}{\partial z}+w\frac{\partial}{\partial z}\frac{\partial \theta}{\partial z}+\frac{\partial u}{\partial z}\frac{\partial \theta}{\partial x}+\frac{\partial v}{\partial z}\frac{\partial \theta}{\partial y}+\frac{\partial w}{\partial z}\frac{\partial \theta}{\partial z}=\frac{\partial Q}{\partial z}$$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;From this equation, we can see that differential diabatic heating, advection of stable air, and vertical wind shear in an environment prone to thermal gradients that can enhance inversions.&lt;/p&gt;&#xA;&lt;p&gt;Intrinsically, the wind speed tends to decrease during an inversion, but not all slow winds note an inversion. Inversions tend to occur overnight into the morning, as the air cools at a slower rate than the land.&lt;/p&gt;&#xA;&lt;p&gt;There are tons of other factors that influence air pollution, but it really depends on the pollutant. For example, ozone pollution won't be affected much by an inversion, with the exception of accumulating morning &lt;span class=&quot;math-container&quot;&gt;$\ce{NO_x}$&lt;/span&gt; for a morning peak. Other factors include the amount of water for PM2.5 formation. There is also wet and dry deposition to consider. The question you are asking is very general.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-08-14T23:32:24.617" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22703" PostTypeId="2" ParentId="19414" CreationDate="2021-08-16T08:51:09.347" Score="0" Body="&lt;p&gt;Here is the suitable publication that calculates the length of day over the entire Earth history.&#xA;&lt;a href=&quot;https://www.researchgate.net/publication/26541355_The_Length_of_the_Day_A_Cosmological_Perspective&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/publication/26541355_The_Length_of_the_Day_A_Cosmological_Perspective&lt;/a&gt;&#xA;Thanks.&#xA;Maxwell&lt;/p&gt;&#xA;" OwnerUserId="23271" LastActivityDate="2021-08-16T08:51:09.347" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22704" PostTypeId="1" CreationDate="2021-08-15T14:36:50.420" Score="4" ViewCount="81" Body="&lt;p&gt;I am working through David Andrews' &amp;quot;An introductuion to atmospheric physics&amp;quot;. (2nd Ed)&lt;/p&gt;&#xA;&lt;p&gt;Question 4.8 concerns finding the relationship between the angle a weather front makes with the ground and the temperatures and along front winds either side of it.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Atmospheric fronts are narrow regions of large horizontal temperature gradient. A simple model takes the front to be a sloping surface across which the temperature&#xA;and along-front wind are discontinuous (with warm air overlying cold), but the pressure&#xA;and cross-front wind are continuous. Take the y-axis along the front and the x-axis pointing towards the cold air and apply the hydrostatic and geostrophic wind relationships to&#xA;the region AB in Figure 4.17. Hence show that the slope α at any level is related to the&#xA;temperatures T1 and T2 and along-front winds v1 and v2 at that level by &lt;span class=&quot;math-container&quot;&gt;$(T_2-T_1)g\tan\alpha = f(v_1T_2 - v_2T_1).$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Figure 4.17:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0qYjK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0qYjK.png&quot; alt=&quot;Diagram of an idealised front&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;My progress:&lt;/p&gt;&#xA;&lt;p&gt;Hydrostatic balance: &lt;span class=&quot;math-container&quot;&gt;$\frac{1}{\rho}\frac{\partial p}{\partial z} = -g$&lt;/span&gt;&#xA;Geostrophic balance (x direction): &lt;span class=&quot;math-container&quot;&gt;$\frac{1}{\rho}\frac{\partial p}{\partial x} = fv$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Integrating hydrostatic balance with respect to z:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\int^{p(z+dz)}_{p(z)} \frac{1}{\rho} dp = -g dz$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Since &lt;span class=&quot;math-container&quot;&gt;$p = R_a \rho T$&lt;/span&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$-gdz = \int^{p(z+ dz)}_{p(z)} \frac{R_a T}{p} dp = R_a \ln p (T_2 - T_1)$&lt;/span&gt;&#xA;(Since pressure is assumed continuous and dz is assumed small.)&lt;/p&gt;&#xA;&lt;p&gt;Integrating geostrophic balance similarly gives me:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$f dx = R_a \ln p (\frac{T_1}{v_1} - \frac{T_2}{v_2})$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Hence &lt;span class=&quot;math-container&quot;&gt;$\tan \alpha = \frac{dz}{dx} = \frac{f (T_2 - T_1) v_1 v_2}{g (T_2 v_1 - T_1 v_2)}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is not the same as the form we are told to aim for.&lt;/p&gt;&#xA;&lt;p&gt;I would really appreciate knowing what I am doing wrong here!&lt;/p&gt;&#xA;" OwnerDisplayName="Salamander" LastActivityDate="2021-08-17T13:10:16.817" Title="How do you find the relationship between the angle a weather front makes with the ground and the temperatures and along front winds either side of it?" Tags="|fluid-dynamics|meteorology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22705" PostTypeId="1" AcceptedAnswerId="22707" CreationDate="2021-08-17T13:22:28.663" Score="3" ViewCount="253" Body="&lt;p&gt;I am curious to know if there was a period of global warming that took place before the start of the last ice age and I would like to know how long this period of global warming lasted.&lt;/p&gt;&#xA;" OwnerUserId="23275" LastEditorUserId="22648" LastEditDate="2021-08-17T18:33:50.820" LastActivityDate="2021-08-18T01:36:30.283" Title="Was there a period of global warming before the start of the last ice age?" Tags="|climate-change|ice-age|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22706" PostTypeId="1" CreationDate="2021-08-17T14:57:25.437" Score="1" ViewCount="110" Body="&lt;p&gt;I've been trying to figure out how these holes formed in the rock. These pictures were taken in Quebec, Canada on  small lake in cottage country. The strange thing is that they are almost both identical. There are no signs of tools used and the lake is very small with not many boats.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lRN9W.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lRN9W.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;a href=&quot;https://i.stack.imgur.com/c5iQU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/c5iQU.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="23276" LastActivityDate="2021-08-18T23:51:02.257" Title="How did these holes form in the rock?" Tags="|geology|rocks|" AnswerCount="1" CommentCount="1" ClosedDate="2021-08-23T06:46:32.033" ContentLicense="CC BY-SA 4.0" />
  <row Id="22707" PostTypeId="2" ParentId="22705" CreationDate="2021-08-18T01:36:30.283" Score="5" Body="&lt;p&gt;There was an interglacial befor the last glaciation:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/oJgBX.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oJgBX.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;glacial–interglacial cycles last ~100,000 years (middle, black line) and consist of stepwise cooling events followed by rapid warmings, as seen in this time series inferred from hydrogen isotopes in the Dome Fuji ice core from Antarctica&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ncdc.noaa.gov/abrupt-climate-change/Glacial-Interglacial%20Cycles&quot; rel=&quot;noreferrer&quot;&gt;NOAA&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2021-08-18T01:36:30.283" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22709" PostTypeId="1" CreationDate="2021-08-18T15:24:51.373" Score="1" ViewCount="34" Body="&lt;p&gt;Some of the requisite for stacking is that the noise and amplitudes need to be uncorrelated. Can someone explain to me why?&lt;/p&gt;&#xA;&lt;p&gt;Also is there a drawback for stacking?&lt;/p&gt;&#xA;" OwnerUserId="23278" LastActivityDate="2021-08-18T15:24:51.373" Title="Preconditions for stacking" Tags="|seismic|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22711" PostTypeId="2" ParentId="22706" CreationDate="2021-08-18T23:51:02.257" Score="0" Body="&lt;p&gt;At first glance I'd say this looks like a granite but its hard to tell from the photos, certainly the rock looks to be a fairly massive (lacking structure). Looking it bit closer I'm now thinking it may be a coarse sandstone/conglomerate, judging by the large clasts that appear to be weathering out between the caves.&lt;/p&gt;&#xA;&lt;p&gt;In either case, both sandstones and granites tend to weather 'spheroidally' into nice rounded shapes. My suspicion is that the rock has some compostional / structural susceptibility to surface weathering where these caves have been formed, perhaps exacerbated by being close to the waterline.&lt;/p&gt;&#xA;&lt;p&gt;Its quite hard to tell without a proper look around though.&lt;/p&gt;&#xA;" OwnerUserId="23285" LastActivityDate="2021-08-18T23:51:02.257" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22712" PostTypeId="2" ParentId="22370" CreationDate="2021-08-19T05:34:35.303" Score="2" Body="&lt;p&gt;&amp;quot;Soil&amp;quot; is a loose amalgam of various earthen materials and organic detritus, thus conditions that create soil in various regions; soil &amp;quot;Thickness&amp;quot; depends on where soil ends and regolith (solid rock) begin&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-08-19T05:34:35.303" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22713" PostTypeId="1" AcceptedAnswerId="22716" CreationDate="2021-08-19T06:33:54.880" Score="3" ViewCount="671" Body="&lt;p&gt;According to my environmental management textbook, the conditions necessary for a temperature inversion are:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;strong&gt;High air pressure&lt;/strong&gt;, which causes the upper air to sink&lt;/li&gt;&#xA;&lt;li&gt;Calm conditions resulting from &lt;strong&gt;high pressure&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;Valleys surrounded by steep-sided hills, which trap the smog&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;One thing I don't understand is how high air pressure is involved. Firstly, how would a temperature inversion occur if the upper air sinks like the first point says? Also, high pressure where? Near to the surface or...?&lt;/p&gt;&#xA;" OwnerUserId="23287" LastEditorUserId="23287" LastEditDate="2022-02-21T02:47:47.600" LastActivityDate="2022-02-21T02:47:47.600" Title="Temperature Inversion" Tags="|meteorology|climate|temperature|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22714" PostTypeId="2" ParentId="22700" CreationDate="2021-08-19T08:10:11.157" Score="2" Body="&lt;p&gt;Sorta. But now you're hypersalinating a soil profile and once it evaporates it's now a salt flat. Better strategy is build &amp;quot;Pools&amp;quot; at high elevation then have gravity send the water back to the ocean in one big loop. Water will evaporate from surface, increasing ambient humidity overtime. On average, swimming pools lose about a quarter of an inch of water each day to evaporation (155 gallons per 1000 square feet) So a one square mile sized retainment area will evaporate 4.3 million gallons a day.&#xA;Another idea is seawater solar still. Pumped water would enter a green house semi-buried The humidity would rise and be diverted to a pump which said water would percolate into the ground. This ground water would sustain new vegetation which in time would humidify the surrounding area. &lt;a href=&quot;https://i.stack.imgur.com/83sO6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/83sO6.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-08-19T08:10:11.157" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22715" PostTypeId="1" CreationDate="2021-08-19T10:13:47.227" Score="2" ViewCount="62" Body="&lt;p&gt;I am looking for videos/image series that show (at least a section of) the (daytime) sky at a given location for a prolonged time (ideally &amp;gt; 1 year).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=KFtwRluSxG0&quot; rel=&quot;nofollow noreferrer&quot;&gt;This youtube video&lt;/a&gt; is one example of what it could look like - a time lapse of an entire year, where a photo at the same spot was taken every day at the same time. I was wondering if there is a (scientific) resource (perhaps in the meteorology/astronomy community) that would give access to better images/videos and for more locations around the world. It could also stem from wildlife cameras or the recording of public webcams; are there repositories for such data?&lt;/p&gt;&#xA;" OwnerUserId="23290" LastEditorUserId="23290" LastEditDate="2021-08-20T08:52:25.027" LastActivityDate="2021-08-20T08:52:25.027" Title="Is there a publicly accessible resource of video/image footage of the sky over an entire year?" Tags="|meteorology|atmosphere|visualization|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22716" PostTypeId="2" ParentId="22713" CreationDate="2021-08-19T12:15:05.687" Score="6" Body="&lt;p&gt;High pressure air &lt;strong&gt;near the surface&lt;/strong&gt; encourages sinking air.&lt;/p&gt;&#xA;&lt;p&gt;Air near the surface that is isolated from the atmosphere higher in the sky tends to move slower.  This is because the ground doesn't move (other than the rotation rate that both the ground and air are moving at).  So the friction of that ground slows air near the surface.&lt;br /&gt;&#xA;Usually air mixes higher into the atmosphere when it is warmed, because &amp;quot;warmer air rises&amp;quot; (it also mixes from wind turbulence).  This is why on average most places have much lower wind speeds around dawn than during the afternoon; most nights see an inversion setup.  The natural cycle tends to almost always be that during daytime heating, the heat strongly encourages rising air, which motivates continued &amp;quot;stirring&amp;quot;, whereas at night the ground cools, and therefore the near-surface air does too, and the lower levels &amp;quot;decouple&amp;quot; from windier conditions above.  This growing layer of disconnect is termed the &lt;a href=&quot;https://forecast.weather.gov/glossary.php?word=boundary%20layer&quot; rel=&quot;noreferrer&quot;&gt;planetary boundary layer&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Places that are stuck in a long bout of stagnant air often have all three factors at work... high pressure hindering air from rising... the inversion of warm air aloft meaning surface air also again being deterred from rising... and then pollution/fog/low clouds/snow on the ground also preventing more of the sunlight from reaching the ground.&lt;/p&gt;&#xA;&lt;p&gt;But the sinking air from high pressure is quite often the kickoff factor that helps the inversion\pollution\fog to get building up [note that air that doesn't mix not only builds up pollutants... but builds up moisture too, favoring more fog, especially when solar heating is reduced].&lt;/p&gt;&#xA;&lt;p&gt;Once the starting conditions are in place, each helps prevent that ground\near-surface air layer from warming (and when it comes to fog\pollution, they tend to move sunlight absorption to the feature, warming that higher layer).  Viola, a mean inversion builds up, and it gets stifling.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2021-08-19T12:15:05.687" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22717" PostTypeId="1" AcceptedAnswerId="22721" CreationDate="2021-08-19T18:03:55.377" Score="4" ViewCount="280" Body="&lt;p&gt;It's often said that waterspouts are weaker than tornadoes, but after some quick searches on the internet, I haven't been able to figure out &lt;em&gt;why&lt;/em&gt; that is.&lt;/p&gt;&#xA;&lt;p&gt;Two relevant sources that I've found:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://theweatherprediction.com/habyhints2/648/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This&lt;/a&gt; claims that &amp;quot;A difference between the two is that a waterspout tends to be weaker. The force of friction is weaker over water thus there is less air available to be drawn into the circulation.&amp;quot; — perhaps this is clear to someone with a stronger background in the sciences than me, but I'm not sure why a weaker force of friction would lead there to be more air (if anything it seems like weaker friction would allow for more air to flow?)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://castle-kaneloon.tripod.com/files/Waterspouts.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;This&lt;/a&gt; source matches my intuition and claims the opposite reason: &amp;quot;In general, waterspouts are not as strong as tornadoes, in spite of the large moisture source and the reduced friction.&amp;quot; but then doesn't explain why tornadoes are stronger&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;So what makes tornadoes stronger?&lt;/p&gt;&#xA;&lt;p&gt;Thanks in advance!&lt;/p&gt;&#xA;" OwnerUserId="23292" LastActivityDate="2021-08-20T02:52:56.663" Title="Why are waterspouts less powerful than tornadoes?" Tags="|meteorology|water|tornado|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22718" PostTypeId="1" CreationDate="2021-08-19T19:42:40.083" Score="4" ViewCount="181" Body="&lt;p&gt;I've been noticing that large (for the northeast US!) lightning storms seem to lose their lightning as they move over downtown Boston. Example gif below (from today, August 19 2021, ~5 am - 11 am local time; taken from lightningmaps.org):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CVTdE.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CVTdE.gif&quot; alt=&quot;Closeup of Connecticut and Massachusetts, showing dozens or hundreds of strikes over central Connecticut decreasing to about a dozen total as it passes over Boston&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This storm isn't as extreme a case as I've more typically seen, where the cities ~10 miles southwest of Boston will get dozens or hundreds of lightning strikes; the Boston College area (about 5 miles from downtown, in a greener/ less paved area) will get dozens; and the downtown will get only a few. But I haven't looked at the data to see how typical that observation &lt;em&gt;really&lt;/em&gt; is.&lt;/p&gt;&#xA;&lt;p&gt;I also looked at this storm's lightning map around New York City and Philadelphia. Those cities appeared to get more lightning than Boston, but then the areas &lt;em&gt;past&lt;/em&gt; them seemed to get almost none at all, almost as if they were in the cities' &amp;quot;shadows&amp;quot; (Aug 18, 10 pm - Aug 19, 9 am):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Di9Xq.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Di9Xq.gif&quot; alt=&quot;Closeup of New Jersey and surrounding regions, showing hundreds of lightning strikes over eastern Pennsylvania that decrease rapidly in number after passing over NYC and Philadelphia. The lightning increases again, at a lower density, over Connecticut.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The lightning then seems to pick up again over Connecticut on its way to Boston.&lt;/p&gt;&#xA;&lt;p&gt;So: &lt;strong&gt;is it true that thunderstorms &amp;quot;lose&amp;quot; their lightning as they pass over cities? If so, why?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Map showing where Boston, NYC, and Philadelphia are:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/P7oMs.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/P7oMs.jpg&quot; alt=&quot;A map showing where Boston, NYC, and Philadelphia are.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22772" LastEditorUserId="543" LastEditDate="2021-08-20T05:52:54.383" LastActivityDate="2021-08-20T05:52:54.383" Title="Does lightning strike density decrease over cities?" Tags="|lightning|thunderstorm|united-states|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22720" PostTypeId="2" ParentId="22715" CreationDate="2021-08-19T20:45:11.440" Score="5" Body="&lt;p&gt;It may be more than you want, and more terrain-focused, but UC San Diego's High Performance Wireless Research and Education Network (HPWREN) has an archive for each of dozens of fixed-angle Southern California wilderness cameras at &lt;a href=&quot;http://hpwren.ucsd.edu/cameras/&quot; rel=&quot;noreferrer&quot;&gt;http://hpwren.ucsd.edu/cameras/&lt;/a&gt;. (I say &amp;quot;more than you want&amp;quot; because the cameras take images every minute, so finding just one image per day will take a little digging.)&lt;/p&gt;&#xA;&lt;p&gt;The cameras have been adapted for use detecting and monitoring wildfires, so that's what they've become best known for. Here's a sample animation:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/F31Uo.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/F31Uo.gif&quot; alt=&quot;Animated GIF of a fire breaking out&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The archives may be a little hard to find since clicking on the thumbnails will usually open a larger version of the same image, but there should be a link to each site. Once on &lt;a href=&quot;http://hpwren.ucsd.edu/cameras/RedM.html&quot; rel=&quot;noreferrer&quot;&gt;http://hpwren.ucsd.edu/cameras/RedM.html&lt;/a&gt;, for example, there's a &amp;quot;data&amp;quot; link for each camera that opens into the actual folder structure of the repository.&lt;/p&gt;&#xA;&lt;p&gt;Please note &lt;a href=&quot;http://hpwren.ucsd.edu/UsageConditions.html&quot; rel=&quot;noreferrer&quot;&gt;the usage conditions&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/user/hpwren/videos&quot; rel=&quot;noreferrer&quot;&gt;There is also a YouTube channel featuring past animations, mostly of fires.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2021-08-19T20:45:11.440" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22721" PostTypeId="2" ParentId="22717" CreationDate="2021-08-20T02:52:56.663" Score="1" Body="&lt;p&gt;Part of it is due to friction. You can see in &lt;a href=&quot;https://www.youtube.com/watch?v=xywOwQxJQV4&amp;amp;t=47s&quot; rel=&quot;nofollow noreferrer&quot;&gt;this video of a landfalling waterspout&lt;/a&gt; the influence that enhanced friction has on tightening the circulation. So, &lt;a href=&quot;https://www.youtube.com/watch?v=FmnkQ2ytlO8&quot; rel=&quot;nofollow noreferrer&quot;&gt;like the ice skater analogy&lt;/a&gt;, enhancing the inflow tightens the circulation by conserving by the conservation of angular momentum.&lt;/p&gt;&#xA;&lt;p&gt;Another thing to consider is that &lt;a href=&quot;https://en.wikipedia.org/wiki/Waterspout#Types&quot; rel=&quot;nofollow noreferrer&quot;&gt;fair weather (non-tornadic) waterspouts are fairly common when it comes to waterspouts&lt;/a&gt;, whereas &lt;a href=&quot;https://en.wikipedia.org/wiki/Landspout&quot; rel=&quot;nofollow noreferrer&quot;&gt;landspouts&lt;/a&gt; are uncommon in comparison, as mesocyclones generate preferentially over land. This means that tornadoes (not landspouts) have access to extra buoyancy over land (more convection=more severe storms= more violent tornadoes).&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-08-20T02:52:56.663" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22722" PostTypeId="1" CreationDate="2021-08-20T12:25:44.230" Score="3" ViewCount="28" Body="&lt;p&gt;A retaining wall 40 cm thick with variable height (thin-walled corner) is being built in the mountainous area. At the time of the geotechnical survey and design, there was no reservoir next to the retaining wall. Now, when they began to build, a pond has formed next to the support on one of the sites. The waters now flow downhill towards the wall, and, naturally, under the foundation. Construction has been suspended because the pit is filled with water. That is, the soils will float. I am a young specialist (I am working for the 4th month), but the project was designed by another person. I was tasked with giving an answer in the near future: events with minimal costs. I look on the Internet: clay, resinization, drainage system. Help me to understand. I am attaching an approximate drawing of this site.&#xA;Soil - gritty soil of slightly weathered shale with loamy&#xA;aggregate up to 30%, with individual sandstone boulders up to 10%. Seismicity - 9 points, freezing depth - 1m. Groundwater up to a depth of 4m is not exposed.&lt;/p&gt;&#xA;" OwnerUserId="23296" LastActivityDate="2021-08-20T12:25:44.230" Title="Water flows under the headwater and soil liquefaction has formed" Tags="|geology|water|mountains|groundwater|mountain-building|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22723" PostTypeId="1" AcceptedAnswerId="22724" CreationDate="2021-08-20T19:54:26.140" Score="1" ViewCount="95" Body="&lt;p&gt;I know &lt;a href=&quot;https://en.wikipedia.org/wiki/Bouvet_Island&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bouvet Island&lt;/a&gt; is quite south. Is there anything southern than that?&lt;/p&gt;&#xA;" OwnerUserId="15185" LastActivityDate="2021-08-21T11:30:21.037" Title="What is the southernmost landmass not covered by the Antarctic Treaty?" Tags="|geography|" AnswerCount="1" CommentCount="3" ClosedDate="2021-08-23T06:46:03.333" ContentLicense="CC BY-SA 4.0" />
  <row Id="22724" PostTypeId="2" ParentId="22723" CreationDate="2021-08-21T10:04:21.510" Score="5" Body="&lt;p&gt;The Antarctic Treaty covers all areas greater than 60° south latitude. A look at a standard globe reveals that the &lt;strong&gt;South Sandwich Islands&lt;/strong&gt; form a chain that nearly reaches but does not cross this parallel. These islands are under the sovereignty of the United Kingdom.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/8YlIs.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;From &lt;a href=&quot;https://ian.macky.net/pat/map/gs/gs.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://ian.macky.net/pat/map/gs/gs.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2021-08-21T11:30:21.037" LastActivityDate="2021-08-21T11:30:21.037" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22725" PostTypeId="1" CreationDate="2021-08-21T19:42:01.817" Score="1" ViewCount="41" Body="&lt;p&gt;I'm looking for projections of past climatic conditions during the last two millennia for northern Europe. I know there are initiatives studying tree rings, but I want to know whether there are interpolated surfaces or, at least, many localities studied in deep. Any suggestion?&lt;/p&gt;&#xA;" OwnerUserId="14509" LastActivityDate="2021-08-21T19:42:01.817" Title="Are there climatic projections for past conditions in Northern Europe?" Tags="|climate-change|climate|history|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22727" PostTypeId="2" ParentId="22639" CreationDate="2021-08-22T11:41:14.697" Score="8" Body="&lt;p&gt;The simple answer to this question is that cold seawater is denser than warm seawater, so it sinks and fills up the abyssal ocean.&lt;/p&gt;&#xA;&lt;p&gt;The water that fills up the abyssal ocean comes from the polar regions. Here's a 1990s plot of temperature in the Atlantic, retrieved from the &lt;a href=&quot;http://sam.ucsd.edu/whp_atlas/atlantic_index.html&quot; rel=&quot;noreferrer&quot;&gt;WOCE Atlantic Ocean Atlas&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EicYM.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EicYM.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;You can see that the coldest water is coming from the Antarctic region (dark blue stuff on the left hand side of the plot) and spreading north.&lt;/p&gt;&#xA;&lt;p&gt;If you look at 1990s salinity instead (plotted below) you can see that the water from the Arctic isn't as cold, but is much saltier (yellow part of the plot spreading from the right hand side and sitting above the water coming north from Antarctica).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RsY0S.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RsY0S.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;When thinking about the density of the ocean, it's important to remember that the ocean isn't filled with water, it is filled with &lt;em&gt;seawater&lt;/em&gt;. Seawater contains &lt;a href=&quot;https://en.wikipedia.org/wiki/Salinity#Seawater&quot; rel=&quot;noreferrer&quot;&gt;approximately 35 g of salt per kilogram of seawater&lt;/a&gt;. The density of seawater therefore depends on &lt;a href=&quot;https://en.wikipedia.org/wiki/Seawater#/media/File:WaterDensitySalinity.png&quot; rel=&quot;noreferrer&quot;&gt;both the temperature and the salinity&lt;/a&gt;. You could write this as&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\rho = \alpha T + \beta S$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;which is correct enough for what we need here. (Small aside, the density also depends on pressure and the coefficients &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\beta$&lt;/span&gt; depend on pressure, salinity, and temperature - you can see this in the curvature of the lines of constant density in &lt;a href=&quot;https://en.wikipedia.org/wiki/Seawater#/media/File:WaterDensitySalinity.png&quot; rel=&quot;noreferrer&quot;&gt;this figure&lt;/a&gt;. Truly understanding the density of seawater is a massive undertaking.)&lt;/p&gt;&#xA;&lt;p&gt;The salt makes two other very important things happen:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;as seawater gets colder, it keeps getting denser (but &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt; gets pretty small at low temperatures, so salinity really dominates the density)&lt;/li&gt;&#xA;&lt;li&gt;seawater freezes at ~-2°C&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;This is why we see water at -0.4°C spreading away from Antarctica in the bottom left corner of that figure. It was colder when it was near the surface, but as it sank it entrained ambient fluid, and warmed up.&lt;/p&gt;&#xA;&lt;p&gt;This explains how we get cold water down into the abyss, but why doesn't the geothermal heat flux simply warm it up?&lt;/p&gt;&#xA;&lt;p&gt;The reason that the geothermal heat flux doesn't heat up the abyssal ocean is that it is too small. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_internal_heat_budget#/media/File:Earth_heat_flow.jpg&quot; rel=&quot;noreferrer&quot;&gt;geothermal heat flux&lt;/a&gt; is up to ~0.5 W/m&lt;span class=&quot;math-container&quot;&gt;$^{2}$&lt;/span&gt;. By comparison, &lt;a href=&quot;https://www.pmel.noaa.gov/ocs/air-sea-fluxes&quot; rel=&quot;noreferrer&quot;&gt;heat fluxes at the surface of the ocean&lt;/a&gt; range from -200 W/m&lt;span class=&quot;math-container&quot;&gt;$^{2}$&lt;/span&gt; to 200 W/m&lt;span class=&quot;math-container&quot;&gt;$^{2}$&lt;/span&gt; (where positive means into the ocean in both cases). The surface heat fluxes and ocean dynamics simply overwhelm the much much smaller geothermal heat flux. Lots of models include a heat flux through the ocean floor, but because it is so small the abyssal ocean remains cold. Here's an &lt;a href=&quot;https://ecco-v4-python-tutorial.readthedocs.io/ECCO_v4_Heat_budget_closure.html#Geothermal-flux&quot; rel=&quot;noreferrer&quot;&gt;example of the heat budget&lt;/a&gt; from an ocean model that includes a flux of heat through the seafloor.&lt;/p&gt;&#xA;&lt;p&gt;So, not much hard maths in there, but I'm not sure we need it.&lt;/p&gt;&#xA;" OwnerUserId="23306" LastEditorUserId="23136" LastEditDate="2021-08-23T01:41:12.223" LastActivityDate="2021-08-23T01:41:12.223" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22728" PostTypeId="1" CreationDate="2021-08-22T18:26:49.840" Score="3" ViewCount="2563" Body="&lt;p&gt;Has anyone managed to read the (latest) full IPCC-report and do you know whether they have taken into account the Earth's core temperature in their models. Besides the IPCC-report, do we know how much the climate and temperature on Earth's surface is effected by it? As I'm guessing, the core temperature of the earth is an very important variable that the climate-models need to have.&lt;/p&gt;&#xA;" OwnerUserId="23307" LastEditorUserId="2470" LastEditDate="2021-08-23T05:54:34.527" LastActivityDate="2023-05-13T22:57:38.637" Title="How much does earth's core temperature affect earth's global surface temperature" Tags="|climate-change|temperature|core|" AnswerCount="4" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22729" PostTypeId="1" CreationDate="2021-08-23T01:24:11.137" Score="1" ViewCount="87" Body="&lt;p&gt;My stepson found this rock on the shore of Lake Michigan and gave it to my son who loves fossils.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZyWrN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZyWrN.jpg&quot; alt=&quot;front side&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hs8kz.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hs8kz.jpg&quot; alt=&quot;back side&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I'd like to really bring out those fossils.&lt;/p&gt;&#xA;&lt;p&gt;What are some techniques that I can try that won't destroy the fossils and may expose other things under the white stone on the front side?&lt;/p&gt;&#xA;" OwnerUserId="23308" LastActivityDate="2021-08-24T04:02:30.310" Title="What are some effective approaches to enhancing fossils in amateur found rocks?" Tags="|geology|fossils|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22730" PostTypeId="1" CreationDate="2021-08-23T01:56:26.267" Score="3" ViewCount="112" Body="&lt;p&gt;Did human-caused deforestation impacted climate and rainfall patterns in the past?&#xA;I'm asking this because I don't know much about the impact of forest cover loss and evapotranspiration on global climate.&lt;/p&gt;&#xA;" OwnerUserId="22045" LastActivityDate="2021-08-23T14:44:34.713" Title="Does deforestation increase global temperatures or just local temperatures?" Tags="|climate-change|paleoclimatology|climatology|deforestation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22731" PostTypeId="2" ParentId="22728" CreationDate="2021-08-23T11:36:06.793" Score="8" Body="&lt;p&gt;It's not the earth's core temperature per se that matters, but rather the amount of heat that flows from the core to the surface. Just like holding a cup of hot coffee - if the mug is insulated, it's fine, but if it's just thin metal, then your fingers will get burnt. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_internal_heat_budget#/media/File:Earth_heat_flow.jpg&quot; rel=&quot;noreferrer&quot;&gt;flux of heat through the surface of the solid earth&lt;/a&gt; is less than ~0.5 W/m&lt;span class=&quot;math-container&quot;&gt;$^{2}$&lt;/span&gt;. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_irradiance#/media/File:Insolation.png&quot; rel=&quot;noreferrer&quot;&gt;sun heats the surface of the earth&lt;/a&gt; at an average rate of ~200 W/m&lt;span class=&quot;math-container&quot;&gt;$^{2}$&lt;/span&gt; (which varies with latitude). We can therefore conclude that the heat coming from the centre of the earth isn't a big factor for the surface temperature of the land.&lt;/p&gt;&#xA;&lt;p&gt;But, what about the ocean?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2000GL012182&quot; rel=&quot;noreferrer&quot;&gt;This paper&lt;/a&gt; from 2001 discusses the impact of the geothermal heat flux on the ocean. They use an approximation of the coupling between the atmosphere&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial T_{ocean}}{\partial t} = \lambda (T_{ocean} - T_{0})$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;that relaxes the ocean temperature, &lt;span class=&quot;math-container&quot;&gt;$T_{ocean}$&lt;/span&gt;, back towards a set temperature, &lt;span class=&quot;math-container&quot;&gt;$T_{0}$&lt;/span&gt;, at a rat of &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt; W m&lt;span class=&quot;math-container&quot;&gt;$^{-2}$&lt;/span&gt; K&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt;. They use a value of 32 W m&lt;span class=&quot;math-container&quot;&gt;$^{-2}$&lt;/span&gt; K&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt;, so an extra heat flux of 0.5 W m&lt;span class=&quot;math-container&quot;&gt;$^{-2}$&lt;/span&gt; leads to a change in surface temperature of &lt;span class=&quot;math-container&quot;&gt;$1.5 \times 10^{-3}$&lt;/span&gt; K. Not really noticeable.&lt;/p&gt;&#xA;&lt;p&gt;If we look at the deep ocean, 3,000 m and below, then their results suggest that this heat flux can make a small but discernible difference; in their model the deep ocean is about 0.2-0.3°C warmer because of the heat flux coming through the sea floor.&lt;/p&gt;&#xA;" OwnerUserId="23306" LastActivityDate="2021-08-23T11:36:06.793" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22732" PostTypeId="2" ParentId="22730" CreationDate="2021-08-23T14:18:10.417" Score="2" Body="&lt;p&gt;Deforestation does impact climate change and rainfall patterns. A &lt;a href=&quot;https://www.carbonbrief.org/deforestation-has-driven-up-hottest-day-temperatures&quot; rel=&quot;nofollow noreferrer&quot;&gt;study in 2018&lt;/a&gt; outlined some of the feedbacks, firstly the direct effect of releasing CO&lt;sub&gt;2&lt;/sub&gt;. Changes in evapotranspiration from deforestation caused 33% of the observed increases in the temperature of the hottest days in regions with at least 15% deforestation. There can be a counter factor in that land albedo can change with deforestation, potentially reflecting more energy back to the sky.&lt;/p&gt;&#xA;&lt;p&gt;The potential feedbacks are further developed in &lt;a href=&quot;https://iopscience.iop.org/article/10.1088/1748-9326/ab738e&quot; rel=&quot;nofollow noreferrer&quot;&gt;recent work on the Amazon&lt;/a&gt;. The direct feedbacks of deforestation on reducing rainfall were small relative to global changes, but cumulative effects can be large.  There is no reason not to think that similar feedbacks will have operated in historical contexts.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastEditorUserId="2470" LastEditDate="2021-08-23T14:44:34.713" LastActivityDate="2021-08-23T14:44:34.713" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22733" PostTypeId="1" CreationDate="2021-08-23T15:10:54.423" Score="1" ViewCount="130" Body="&lt;p&gt;The kind of crop I am interested in measuring is the cabbage.&lt;/p&gt;&#xA;&lt;p&gt;I am currently in the midst of doing an academic research entitled &amp;quot;An Experimental Quantitative Study on Crops' Growth on Natural vs Artificial Lighting (CEA)&amp;quot; where I compare the crop quality cultivated under natural sunlight vs artificial lighting in CEA.&lt;/p&gt;&#xA;&lt;p&gt;As it is a quantitative type, I am having trouble in quantifying the results and what proper quantitative methodologies do I have to employ to make the research successful.&lt;/p&gt;&#xA;&lt;p&gt;Follow-up question:&lt;/p&gt;&#xA;&lt;p&gt;After identifying the qualities of the crop I want to measure, what instruments are required, appropriate graphs to be illustrated for this kind of topic, and what methods should be employed to &amp;quot;measure a crop's quality&amp;quot;?&lt;/p&gt;&#xA;&lt;p&gt;Edit: Made it more specific&lt;/p&gt;&#xA;" OwnerUserId="23312" LastEditorUserId="23312" LastEditDate="2021-08-24T00:26:22.403" LastActivityDate="2021-08-24T18:39:46.193" Title="What qualities of a crop are measured?" Tags="|agriculture|research|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="22734" PostTypeId="2" ParentId="22733" CreationDate="2021-08-24T00:52:30.087" Score="1" Body="&lt;p&gt;In the most simplistic sense, crop yield is the only thing that matters.  You could simply weigh all your usable product at the end of harvest.  Crop growth time is also an important consideration.  Calculate the total yield over a specified time period and let the biggest yield win!&lt;/p&gt;&#xA;&lt;p&gt;Other than quantity, there are several aspects of crop quality that increase desirability:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Taste: is the crop too bitter or characterized by mineral or fertilizer?&lt;/li&gt;&#xA;&lt;li&gt;Crop Hardiness: is the crop more susceptible to disease or other &lt;a href=&quot;https://en.wikipedia.org/wiki/Cabbage#Cultivation_problems&quot; rel=&quot;nofollow noreferrer&quot;&gt;cultivation problems&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Growing Requirements: do the crops require more water or nutrient than others?&lt;/li&gt;&#xA;&lt;li&gt;Sustainability: How does pesticide/fertilizer use and high crop density affect soil quality?  Do you need to rotate crops or go fallow?&lt;/li&gt;&#xA;&lt;li&gt;Marketability: Do you have the best &lt;a href=&quot;https://smallfarmersjournal.com/cabbage/&quot; rel=&quot;nofollow noreferrer&quot;&gt;variety&lt;/a&gt;, organic certification, or other features that raise the price value of your crop.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Farmers regularly inspect their crop and soil for disease and desirability.  They also keep track of how much water, nutrient, and chemical is applied.  Finally, they weigh (or count) the final crop yield and calculate total sales.&lt;/p&gt;&#xA;&lt;p&gt;Light influence on crop quality is a common agricultural question, and you should use prior work in the community as an initial model for your experiment.  For instance, a quick search turned up &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3949401/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Photosynthesis under artificial light: the shift in primary and secondary metabolism (Darko et al, 2014)&lt;/a&gt;, but I'm sure there are many others.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2021-08-24T06:09:52.763" LastActivityDate="2021-08-24T06:09:52.763" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22735" PostTypeId="2" ParentId="22728" CreationDate="2021-08-24T03:31:54.190" Score="3" Body="&lt;p&gt;This &lt;a href=&quot;https://skepticalscience.com/heatflow.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Skeptical Science article&lt;/a&gt; explains that geothermal is very small, &lt;span class=&quot;math-container&quot;&gt;$0.09W/m^2$&lt;/span&gt;, compared to radiant heat flows. It also does not change much in time, so it can be neglected in climate &lt;em&gt;change&lt;/em&gt; calculations.&lt;/p&gt;&#xA;&lt;p&gt;For an airless planet the equilibrium temperature &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; can be calculated from&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ F=\sigma T^4$$&lt;/span&gt;where &lt;span class=&quot;math-container&quot;&gt;$F$&lt;/span&gt; is the average absorbed heat flux at the surface and &lt;span class=&quot;math-container&quot;&gt;$\sigma$&lt;/span&gt; is the Stefan-Boltzmann constant. If there is an additional internal flux &lt;span class=&quot;math-container&quot;&gt;$I$&lt;/span&gt;,  the equilibrium temperature is increased by &lt;span class=&quot;math-container&quot;&gt;$\Delta$&lt;/span&gt;:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$F+I=\sigma(T+\Delta)^4$$&lt;/span&gt;&#xA;For small &lt;span class=&quot;math-container&quot;&gt;$I$&lt;/span&gt; this leads to&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\Delta \approx  \frac{TI}{4F}$$&lt;/span&gt;&#xA;Without the atmosphere, &lt;span class=&quot;math-container&quot;&gt;$I$&lt;/span&gt; is three orders of magnitude smaller than &lt;span class=&quot;math-container&quot;&gt;$F$&lt;/span&gt;, so &lt;span class=&quot;math-container&quot;&gt;$\Delta$&lt;/span&gt; is a fraction of a degree. I don't think the atmosphere would amplify this effect.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2021-08-24T17:10:41.537" LastActivityDate="2021-08-24T17:10:41.537" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22736" PostTypeId="1" AcceptedAnswerId="22738" CreationDate="2021-08-24T03:38:19.553" Score="4" ViewCount="110" Body="&lt;p&gt;Suppose that the IPCC's best estimate of climate sensitivity (3 K) is relevant and that the Keeling curve will increase as now, with a certain procent more emission next year than previous year, into year 2100, when would the average temperature earliest become low enought for a new period of glaciation, due to the Milankovitch cycles?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/q8DMD.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/q8DMD.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/y13DG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/y13DG.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="16809" LastEditorUserId="16809" LastEditDate="2021-08-24T04:04:40.847" LastActivityDate="2021-08-24T05:01:19.567" Title="When would the next glaciation appear? Worst case" Tags="|climate-change|climatology|glaciation|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22737" PostTypeId="2" ParentId="22729" CreationDate="2021-08-24T04:02:30.310" Score="3" Body="&lt;p&gt;Your best bet is a dental pick and time, maybe a little superglue. &lt;a href=&quot;https://www.youtube.com/watch?v=LLAGC3QpINI&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; is a video on using this method, its time consuming but you are less likely to destroy anything. there are faster method but without training they are also likely to destroy the fossils especially with smaller fossils.&lt;/p&gt;&#xA;&lt;p&gt;Alternatively you can try polishing which may work, without knowing the type of rock matric it can be hard to tell. &lt;a href=&quot;https://www.youtube.com/channel/UC2LYE_RzxRZWNmddKFWV6Kw&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; is a series of video on polishing and preparing private fossils. just don't try any of his more aggressive methods on something so small.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2021-08-24T04:02:30.310" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22738" PostTypeId="2" ParentId="22736" CreationDate="2021-08-24T05:01:19.567" Score="2" Body="&lt;p&gt;Milankovich cycles are steady predictors, so sometime in the next 24-50 thousand years. But &amp;quot;Glaciation&amp;quot; is a broad terms, glaciers take long time to accumulate, but they accumulate, EVEN NOW. 100 years is simply too short a time frame to judge circumstances for long term climate trends. We just emerged from the little ice age, during which there were glaciers, that receded by the 1880's&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-08-24T05:01:19.567" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22740" PostTypeId="1" AcceptedAnswerId="24839" CreationDate="2021-08-24T05:38:27.880" Score="8" ViewCount="702" Body="&lt;p&gt;After reading about the NAC (North Atlantic Current) weakening in the news, we got to wondering about its history and that of the gulf stream. Specifically, how and when did they start? Were there conditions during the last ice age that prevented such currents forming, and we can point to a time X when the earth was warm (and the ice receeded enough) for them to do so? Or were they always there, just maybe shorter? The fact that there's worries about the NAC cutting off and europe cooling down considerably points to at least that one not being a guaranteed, always on thing.&lt;/p&gt;&#xA;&lt;p&gt;Googling &amp;quot;how old is&amp;quot; or &amp;quot;age of&amp;quot; for these currents only returns dates for when they were discovered - and I'm fairly sure the gulf stream existed prior to 1513.&lt;/p&gt;&#xA;&lt;p&gt;So I hope that someone here has knowledge beyond that: how did these ocean currents come to be? And roughly when in our planet's long history would that have happened?&lt;/p&gt;&#xA;" OwnerUserId="23315" LastEditorUserId="24481" LastEditDate="2021-09-27T09:46:10.753" LastActivityDate="2023-02-03T14:07:06.430" Title="how old are the gulf stream and the NAC?" Tags="|oceanography|paleoclimatology|ocean-currents|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22741" PostTypeId="1" AcceptedAnswerId="22742" CreationDate="2021-08-24T09:10:42.743" Score="11" ViewCount="2517" Body="&lt;p&gt;According to &lt;a href=&quot;https://www.statista.com/statistics/264472/number-of-satellites-in-orbit-by-operating-country/#:%7E:text=Of%20the%203%2C372%20active%20artificial%20satellites%20orbiting%20the,their%20nearest%20competitor%2C%20China%2C%20accounting%20for%20only%20412.&quot; rel=&quot;nofollow noreferrer&quot;&gt;this website&lt;/a&gt;, there were 3,372 active satellites in orbit at the beginning of 2021. Furthermore, SpaceX is planning to launch 12,000 satellites to provide cheap internet for everybody, among other functions.&lt;/p&gt;&#xA;&lt;p&gt;Does this huge collective quantity of objects (together with space trash) reflect away enough solar radiation to have a measurable effect? Could this affect earth's climate, mitigating climate change?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-09-03T13:33:16.783" LastActivityDate="2021-10-19T03:15:07.827" Title="Do satellites decrease the amount of solar radiation reaching Earth?" Tags="|climate-change|climate|satellites|" AnswerCount="2" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="22742" PostTypeId="2" ParentId="22741" CreationDate="2021-08-24T12:23:26.823" Score="23" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Does this huge collective quantity of objects (together with space trash) reflect away enough solar radiation to have a measurable effect? Could this affect Earth's climate, mitigating climate change?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;No.&lt;/p&gt;&#xA;&lt;p&gt;Suppose, instead of 12,000 tiny satellites, SpaceX was planning on launching 12,000 satellites the size of the International Space Station. The ISS, with its huge solar arrays, has a cross section of about 7,000 square meters (6,528 square meters for the arrays alone). &lt;em&gt;Fun fact:&lt;/em&gt; This is about the size of a FIFA-sanctioned international match field. I'll bump up the size to 8250 square meters, the maximum size of a FIFA-sanctioned international match field.&lt;/p&gt;&#xA;&lt;p&gt;The ISS blocks sunlight that would otherwise hit the Earth about half of the time. I'll halve the 12,000 satellites to 6,000 to reflect this. Six thousand maximum-sized FIFA-sanctioned international match fields results in an area of 49.5 square kilometers. The Earth's cross section to sunlight is &lt;span class=&quot;math-container&quot;&gt;$\pi r^2$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; is the Earth's mean radius (6371 km). This cross section area is &lt;span class=&quot;math-container&quot;&gt;$1.275\times10^8$&lt;/span&gt; square kilometers. That's over 2.5 million times larger than those 6000 maximum-sized FIFA-sanctioned international match fields.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Summary:&lt;/strong&gt; Even 12,000 satellites larger than the ISS would have a minimal impact on the amount of sunlight hitting the Earth. The 12,000 satellites SpaceX is planning to launch are orders of magnitude smaller than the ISS. The impact is in the noise.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="22648" LastEditDate="2021-08-26T10:39:56.430" LastActivityDate="2021-08-26T10:39:56.430" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="22745" PostTypeId="1" CreationDate="2021-08-26T11:36:48.580" Score="1" ViewCount="82" Body="&lt;p&gt;I have contour maps showing conductivity and in-phase data from an electromagnetic survey done on a ground, where, supposedly, an underground sewer system is running horizontally across the survey area. The In-phase data shows a clear indication of it, but the conductivity data is just blank.&lt;/p&gt;&#xA;&lt;p&gt;Can anyone help me under stand why? Shouldn't the conductivity data show at least something? The survey was carried out both vertically and horizontally on the survey area using a CMD.&lt;/p&gt;&#xA;&lt;p&gt;And what exactly does the in-phase data show in a electromagnetic survey? On the manual it just says that 'It is closely related to magnetic susceptibility of measured material.' Does this mean it's measuring the magnetic susceptibility?&lt;/p&gt;&#xA;" OwnerUserId="23278" LastEditorUserId="23278" LastEditDate="2021-08-26T12:00:09.180" LastActivityDate="2021-08-26T12:00:09.180" Title="Understanding the EM survey results" Tags="|geophysics|electromagnetism|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="22746" PostTypeId="1" AcceptedAnswerId="22747" CreationDate="2021-08-26T12:53:35.317" Score="17" ViewCount="1430" Body="&lt;p&gt;This is a graph from a reputable source of CO&lt;sub&gt;2&lt;/sub&gt; concentrations in atmosphere the last decades:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/paqr8.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/paqr8.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I would expect that, as we have been using clean energy for some years now, the graph would start to trend to the horizontal asymptote we all wish to see soon.&lt;/p&gt;&#xA;&lt;p&gt;Why is the start of the energetic transition not reflected in the graph?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-08-28T02:09:40.553" LastActivityDate="2022-03-03T04:38:59.290" Title="Why is the energy transition start not reflected in the CO2 concentration graphs?" Tags="|climate-change|energy|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22747" PostTypeId="2" ParentId="22746" CreationDate="2021-08-26T15:04:40.587" Score="26" Body="&lt;h1&gt;Because the energy transition has not yet been sufficient to reduce annual carbon emissions.&lt;/h1&gt;&#xA;&lt;p&gt;From Our World in Data, here's &lt;a href=&quot;https://ourworldindata.org/grapher/annual-co-emissions-by-region&quot; rel=&quot;noreferrer&quot;&gt;annual total CO&lt;sub&gt;2&lt;/sub&gt; emissions, by world region&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/60eag.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/60eag.png&quot; alt=&quot;Annual total CO2 emissions by world region&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Since the 1960s, growth in low-carbon energy sources has only grown from about 6% to about 16% (&lt;a href=&quot;https://ourworldindata.org/grapher/low-carbon-share-energy?tab=chart&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;)-- not enough to make a dent, given that total energy use has grown faster than that.&lt;/p&gt;&#xA;&lt;p&gt;Looking just at electricity, here's &lt;a href=&quot;https://ourworldindata.org/grapher/elec-fossil-nuclear-renewables?stackMode=absolute&amp;amp;country=%7EOWID_WRL&quot; rel=&quot;noreferrer&quot;&gt;production from fossil fuels, nuclear, and renewables&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0E3j7.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0E3j7.png&quot; alt=&quot;World electricity production by source&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Use of renewables is growing, and faster than fossil fuel use is growing -- but fossil fuel use continues to grow.&lt;/p&gt;&#xA;" OwnerUserId="7741" LastActivityDate="2021-08-26T15:04:40.587" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22748" PostTypeId="1" CreationDate="2021-08-27T12:15:00.330" Score="4" ViewCount="76" Body="&lt;p&gt;My professor posed this question, without any relevant material. I suppose the currents last until the density gradient is neutralized, but I can't find any literature nor articles on this, regarding the time scale. Any suggestions? Thanks!&lt;/p&gt;&#xA;" OwnerUserId="23337" LastActivityDate="2022-03-01T13:55:51.753" Title="How long do geostrophic currents last?" Tags="|geophysics|oceanography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22749" PostTypeId="1" AcceptedAnswerId="22752" CreationDate="2021-08-29T08:37:05.303" Score="5" ViewCount="135" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;em&gt;Water diffuses from an area of high concentration to an area of low concentration.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;By that &lt;em&gt;principle&lt;/em&gt;, I would expect water from the troposphere to &lt;strong&gt;diffuse&lt;/strong&gt; into the stratosphere, where water content is significantly lower than in the former. However, this is not what happens; a reason given in my textbook is as follows:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Increasing temperatures&lt;/strong&gt; stop clouds and weather systems from reaching this height: it acts like the lid on top of a boiling pan above the active weather systems in the troposphere. &lt;span class=&quot;math-container&quot;&gt;$^{1}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;How is it that rising temperatures play a role here?&lt;/strong&gt; Plus, the hottest region of the stratosphere (its top) isn't much hotter/colder compared to the troposphere, so a &lt;em&gt;temperature gradient&lt;/em&gt;  wouldn't be responsible, would it?&lt;/p&gt;&#xA;&lt;p&gt;Essentially, &lt;strong&gt;what role does temperature play with weather &amp;quot;regulation&amp;quot; and how does it prevent weather formation &amp;amp; water entering the stratosphere through diffusion?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;em&gt;1. Pallister, John. IGCSE Environmental Management. Second ed., Oxford University Press, 2017.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="23287" LastEditorUserId="23287" LastEditDate="2021-08-29T08:42:51.433" LastActivityDate="2021-08-30T11:16:29.580" Title="How is weather formation prevented in the stratosphere?" Tags="|meteorology|temperature|water|water-vapour|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22750" PostTypeId="2" ParentId="22590" CreationDate="2021-08-29T22:37:25.910" Score="4" Body="&lt;p&gt;In theory, the methane emissions would warm the earth about 25 times more than the carbon dioxide emissions.&lt;/p&gt;&#xA;&lt;p&gt;That's because of something called the &lt;strong&gt;global warming potential.&lt;/strong&gt; The global warming potential of a greenhouse gas is how much it warms the planet compared to carbon dioxide's base value of 1. As you might expect, methane's GWP is 25.&lt;/p&gt;&#xA;&lt;p&gt;Sources:&#xA;&lt;a href=&quot;https://www.epa.gov/ghgemissions/overview-greenhouse-gases#methane&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.epa.gov/ghgemissions/overview-greenhouse-gases#methane&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.kidsfightclimatechange.org/learn/basics&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.kidsfightclimatechange.org/learn/basics&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="23350" LastActivityDate="2021-08-29T22:37:25.910" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22751" PostTypeId="1" CreationDate="2021-08-30T06:56:30.493" Score="1" ViewCount="31" Body="&lt;p&gt;I would like to know the relation of aerosol particle size (2,5 and 10 microns) with the measurements from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Sentinel-5#Tropomi&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sentinel-5P TROPOMI&lt;/a&gt; data, in the wavelengths 340-380 and 358-388 nm bands.&lt;/p&gt;&#xA;" OwnerUserId="22895" LastEditorUserId="2470" LastEditDate="2021-08-30T08:53:41.300" LastActivityDate="2021-08-30T08:53:41.300" Title="How can I relate aerosol particle size (2, 5 and 10 microns) with the aerosol index measurement of the Sentinel-5P (TROPOMI) data sets?" Tags="|remote-sensing|satellites|weather-satellites|aerosol|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22752" PostTypeId="2" ParentId="22749" CreationDate="2021-08-30T11:16:29.580" Score="3" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;By that principle, I would expect water from the troposphere to diffuse into the stratosphere, where water content is significantly lower than in the former.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You are forgetting that water is not nearly as volatile as are the long-lived gases that comprise the bulk of the Earth's atmosphere. Water's triple point temperature is 0.01° C. The triple point temperatures of nitrogen, oxygen, and argon are -209.97° C, -218.79° C, and -189.34° C. There is no point in the Earth's atmosphere where those long-lived gases can make the phase transition from gas to liquid or solid. There are plenty of places in the Earth's troposphere where water vapor can do just that. We call the result snow or rain.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;How is it that rising temperatures play a role here?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It's not just rising temperatures in the stratosphere with increased altitude, although that does play a role. The decreasing temperatures in the troposphere with increased altitude also plays a role. The temperature at the top of the troposphere / bottom of the stratosphere is around -50° C. The Earth's atmosphere can sustain but a paltry amount of water vapor at the temperature and pressure at the tropopause.&lt;/p&gt;&#xA;&lt;p&gt;Where the increasing temperatures with increased altitude in the stratosphere does play a role is that this makes the tropopause a temperature inversion layer. Inversion layers tend to stop vertical transport of air. Inversion layers in the lower atmosphere are one of the reasons pollution can be rather nasty in cities such as Los Angeles and Denver. Diffusion of water vapor from the upper troposphere into the lower stratosphere is still possible, but at -50° C, there is very little water vapor available to diffuse across the tropopause.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2021-08-30T11:16:29.580" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22753" PostTypeId="1" CreationDate="2021-08-30T16:05:37.507" Score="1" ViewCount="381" Body="&lt;p&gt;I know that a majority of thunderstorms form in the daytime due to convection from sunlight heating in a moist, unstable airmass. Once the sun begins to set, these storms dissipate.&lt;/p&gt;&#xA;&lt;p&gt;But on some mornings (in the summer, of course) I'll check my local &lt;em&gt;NWS radar&lt;/em&gt; (in northern Ohio) before I set out for work and see that it's alive with storm cells that have popped up from seemingly out of nowhere. They are not existing storms that moved into the range of my local radar, but brand new cells that just appeared about an hour before. These storms usually contain a lot of lightning and bring sustained heavy rain, sometimes to the point of minor flooding.&lt;/p&gt;&#xA;&lt;p&gt;What causes early morning storms to pop up like this when it's typically the coolest time of the day and convection is at a minimum? It's something I've been thinking about for quite a while now.&lt;/p&gt;&#xA;" OwnerUserId="23353" LastEditorUserId="22648" LastEditDate="2021-08-31T04:26:38.457" LastActivityDate="2021-08-31T18:42:57.563" Title="What causes thunderstorms to develop in the early dawn hours?" Tags="|meteorology|thunderstorm|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22758" PostTypeId="1" CreationDate="2021-08-31T16:28:44.587" Score="4" ViewCount="82" Body="&lt;p&gt;Looking at equatorial Africa in Google Maps, the western part – Guinea, the Congo – is the dark green of tropical rain forest that I would expect of a wet equatorial region, by analogy with the Amazon basin and similar latitudes in east Asia.&lt;/p&gt;&#xA;&lt;p&gt;By contrast, the eastern part – Kenya, Tanzania – is the light green of savanna and the light brown of semidesert or desert, indicating much drier conditions that at other longitudes, are more associated with the edges of the Hadley cells, 20-30 degrees away from the equator.&lt;/p&gt;&#xA;&lt;p&gt;That's not at all the pattern I would've expected. By the basic logic of convection cells, plus analogy with other continents, I would've expected moist conditions across the width of equatorial Africa, but failing that, because the prevailing winds in the tropics blow from the east, I would've expected the eastern part of the continent (which gets wind from the Indian Ocean) to be wet and the western part (which gets wind that has blown some distance over land) to be drier.&lt;/p&gt;&#xA;&lt;p&gt;Why is it that the western part of equatorial Africa is wet and the eastern part is dry?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ehETS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ehETS.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7911" LastEditorUserId="543" LastEditDate="2021-08-31T16:44:56.573" LastActivityDate="2021-08-31T16:44:56.573" Title="Why is equatorial Africa wetter in the west than the east?" Tags="|meteorology|wind|rainfall|rain|" AnswerCount="0" CommentCount="6" ClosedDate="2021-09-01T22:42:45.983" ContentLicense="CC BY-SA 4.0" />
  <row Id="22759" PostTypeId="2" ParentId="22753" CreationDate="2021-08-31T18:42:57.563" Score="2" Body="&lt;p&gt;Do you have a specific date and time that comes to mind? There are a couple of different causes of nocturnal convection that I immediately think of. I'll list a few, and expand on the one that I think is most likely to be the culprit.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;As one commenter named, a synoptic scale feature, such as a cold front or occluded front could produce a lifting mechanism that taps into the residual layer.&lt;/li&gt;&#xA;&lt;li&gt;Remnants of a tropical cyclone. Given the scenario you described, this is unlikely.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Mesoscale_convective_system&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mesoscale Convective Systems&lt;/a&gt; that begin to form during dusk, and propagate well afterwards. Given what you described, this may not be the case.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://journals.ametsoc.org/view/journals/atsc/76/1/jas-d-17-0172.1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bores and Atmospheric Gravity Waves&lt;/a&gt; that initiate convection. This is definitely a possibility, but it might require convection upstream.&lt;/li&gt;&#xA;&lt;li&gt;The likely culprit is the influence of a &lt;a href=&quot;http://www.theweatherprediction.com/severe/llj/&quot; rel=&quot;nofollow noreferrer&quot;&gt;low level jet&lt;/a&gt; (LLJ). The LLJ is formed by the temperature difference between the Rockies and the Plains. The temperature gradient driving the LLJ might be an oversimplified reasoning for the driving of the LLJ, but &lt;a href=&quot;https://journals.ametsoc.org/view/journals/atsc/73/8/jas-d-15-0307.1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;all of the mathematics and theory behind it&lt;/a&gt;, such as the alignment of the geostrophic and ageostrophic wind, deserves a full blown lecture. Why ramble on about these LLJs? They can initiate convection through &lt;a href=&quot;https://journals.ametsoc.org/view/journals/mwre/146/8/mwr-d-18-0002.1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;low level convergence&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;What all of these have in common is that they are all called &lt;a href=&quot;https://en.wikipedia.org/wiki/Forced_convection&quot; rel=&quot;nofollow noreferrer&quot;&gt;forced convection&lt;/a&gt;. &lt;a href=&quot;https://journals.ametsoc.org/view/journals/mwre/146/9/mwr-d-18-0040.1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;This paper&lt;/a&gt; that I found also lists a couple of mechanisms, some of which I mentioned, but others I am not that familiar with (elevated convergent layers, MPS circulation).&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-08-31T18:42:57.563" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22762" PostTypeId="1" CreationDate="2021-09-02T12:27:29.297" Score="2" ViewCount="66" Body="&lt;p&gt;In this remote island (the most remote!) there is a volcano that wikipedia report as inactive, but from google maps there seems to be some ash in the sky. Are there some ongoing eruption?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/AKGDN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AKGDN.jpg&quot; alt=&quot;image&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12097" LastActivityDate="2021-09-02T12:27:29.297" Title="Bouvet Island volcano" Tags="|volcanology|volcanic-eruption|islands|" AnswerCount="0" CommentCount="4" ClosedDate="2021-09-06T10:35:31.227" ContentLicense="CC BY-SA 4.0" />
  <row Id="22763" PostTypeId="2" ParentId="16881" CreationDate="2021-09-03T02:31:24.700" Score="2" Body="&lt;p&gt;During the drilling, the hole was filled with &amp;quot;drilling mud&amp;quot;, which served to lubricate the bit, carry the cuttings to the surface and power the bit via a turbine.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;When  the  well  reaches  a highest  depth,  there  is  a  significant  difference between  the  hydrostatic  pressure of the mud column and the lithostatic pressure due to the weight of the rocks. As a result, the walls of&#xA;the  well  can  be  destroyed (bend  in),  which leads  to  serious  complications  during drilling.  In  order  to  balance the rock pressure, there is an increase of density of the drilling mud to about 2 g per centimeter cubic.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://iopscience.iop.org/article/10.1088/1755-1315/459/5/052066/pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Application of Superdeep Drilling Technology for Study of the Earth Crust, O V Savenok et al 2020&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I expect they would not have gone to the expense of pumping out the mud (if even possible) as it would result in the hole caving in.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2021-09-03T02:48:24.587" LastActivityDate="2021-09-03T02:48:24.587" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22764" PostTypeId="1" CreationDate="2021-09-03T15:24:52.233" Score="4" ViewCount="51" Body="&lt;p&gt;I have been doing a lot of digging in a thick murine clay as part of a construction project. In the course of doing this work, we noticed significant bands and streaks of blue color in the clay, which I know can be sign of silver.&lt;/p&gt;&#xA;&lt;p&gt;Recently, we dug a hole using a &lt;em&gt;hydrojet&lt;/em&gt; and noticed metallic flocculation in the froth. This flocculation is  dark gray, but also has tiny flakes of silver color. On examining the flakes under a metallurgical microscope, they tend to have rounded edges and surfaces and have a silver-like luster, so that excludes mica.&lt;/p&gt;&#xA;&lt;p&gt;We have exposed the material to a reducing flame but do not see much change either in the metallic element or the matrix, which is a murine silica clay.&lt;/p&gt;&#xA;&lt;p&gt;Since silver rarely occurs natively, I am hesitant to identify it as silver, but nevertheless that creates the question of what it might be. One possibility is vivianite, an iron-phosphorous mineral, or perhaps arsenic.&lt;/p&gt;&#xA;&lt;p&gt;Are there any easy tests that can be done to identify it as silver? I know I can do a bead test, but the bead test for silver is dark gray and we already have a dark gray flocculation, so I suspect that test would be positive. What's the next step?&lt;/p&gt;&#xA;&lt;p&gt;(Please submit answers that I can do. Saying &amp;quot;send it to a lab&amp;quot; is obvious and I am already aware of that option.)&lt;/p&gt;&#xA;" OwnerUserId="2491" LastEditorUserId="22648" LastEditDate="2021-09-04T07:58:52.657" LastActivityDate="2021-09-04T07:58:52.657" Title="Identifying metallic element or compound in murine clay" Tags="|mineralogy|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22767" PostTypeId="1" CreationDate="2021-09-05T02:13:37.093" Score="4" ViewCount="36" Body="&lt;p&gt;On page 142 of Lackmann's &lt;em&gt;Midlatitude Synoptic Meteorology&lt;/em&gt;, Equation 6.7 gives the derivative of the Boussinesq buoyancy &lt;span class=&quot;math-container&quot;&gt;$b = \frac{g \theta'}{\theta_0 (z)}$&lt;/span&gt; (perturbation potential temperature &lt;span class=&quot;math-container&quot;&gt;$\theta'$&lt;/span&gt; and base state &lt;span class=&quot;math-container&quot;&gt;$\theta_0 (z)$&lt;/span&gt;) as&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\frac{db}{dt}&#xA;= -w \frac{g}{\theta_{00}} \frac{d \theta_0}{dz}&#xA;\end{equation}&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$\theta_{00}$&lt;/span&gt; is the base state potential temperature &lt;span class=&quot;math-container&quot;&gt;$\theta_0 (z)$&lt;/span&gt; at &lt;span class=&quot;math-container&quot;&gt;$z = 0$&lt;/span&gt;. While I understand this to be an application of the chain rule&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\frac{db}{dt}&#xA;= \frac{\partial z}{\partial t} \frac{\partial \theta_0}{\partial z} \frac{\partial b}{\partial \theta_0},&#xA;\end{equation}&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;I am unable to see why&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\frac{\partial b}{\partial \theta_0}&#xA;= - \frac{g}{\theta_{00}}&#xA;\end{equation}&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;when I instead would expect&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\frac{\partial b}{\partial \theta_0}&#xA;= - \frac{g \theta'}{\theta_0^2 (z)}.&#xA;\end{equation}&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Any help would be much appreciated!&lt;/p&gt;&#xA;" OwnerUserId="24383" LastEditorUserId="22648" LastEditDate="2021-09-05T04:56:56.687" LastActivityDate="2021-09-05T04:56:56.687" Title="Dynamic frontogenesis derivation" Tags="|meteorology|temperature|mathematics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22768" PostTypeId="1" CreationDate="2021-09-05T12:37:45.127" Score="5" ViewCount="495" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FTZm4.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FTZm4.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;How would one go about calculating the value for back radiation(324 in this diagram) if it wasn't provided.&lt;/p&gt;&#xA;&lt;p&gt;According to this &lt;a href=&quot;https://earthobservatory.nasa.gov/features/EnergyBalance#:%7E:text=The%20amount%20of%20heat%20radiated,energy%20by%20raising%20its%20temperature.&quot; rel=&quot;noreferrer&quot;&gt;website&lt;/a&gt;, it is &amp;quot;equivalent to 100 percent of the incoming solar energy&amp;quot; but from this diagram, that statement appears to be false as the incoming solar energy is 342 while the back radiation is 324.&lt;/p&gt;&#xA;&lt;p&gt;Could someone tell me how to do it? Or is it just not possible?&lt;/p&gt;&#xA;" OwnerUserId="24381" LastActivityDate="2021-09-25T08:58:32.680" Title="How to calculate the back radiation from greenhouse gases?" Tags="|greenhouse-gases|atmospheric-radiation|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="22769" PostTypeId="1" CreationDate="2021-09-05T19:13:06.780" Score="4" ViewCount="322" Body="&lt;p&gt;I wonder whether the amount of UVA radiations one receives depends on the latitude one is located, and if so, to what extent? I looked at UV indices of different cities, but those are useless since they mostly take into account UVB, which unlike UVA depends on the weather condition (e.g., the presence of clouds will decrease UVB radiations but not UVA radiations {1}).&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;{1} Calbó, Josep, David Pages, and Josep‐Abel González. &amp;quot;Empirical studies of cloud effects on UV radiation: A review.&amp;quot; Reviews of Geophysics 43, no. 2 (2005). &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2004RG000155&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2004RG000155&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="587" LastEditorUserId="587" LastEditDate="2021-09-05T20:32:29.557" LastActivityDate="2021-09-06T20:55:29.227" Title="Does the amount of UVA radiations one receives depend on the latitude one is located, and if so, to what extent?" Tags="|uv-light|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22770" PostTypeId="2" ParentId="22769" CreationDate="2021-09-05T20:50:25.633" Score="1" Body="&lt;p&gt;Yes according to &lt;a href=&quot;https://www.biointeractive.org/sites/default/files/skincolorselection-educator-act.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.biointeractive.org/sites/default/files/skincolorselection-educator-act.pdf&lt;/a&gt; (&lt;a href=&quot;https://web.archive.org/web/20210906203902/https://www.biointeractive.org/sites/default/files/skincolorselection-educator-act.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;mirror&lt;/a&gt;):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;How do you explain the relationship between the UV Index and latitude? (In other words, why does UV&#xA;intensity change with latitude?)&lt;/p&gt;&#xA;&lt;p&gt;The answer has to do with the &lt;strong&gt;angle of Earth relative to the sun&lt;/strong&gt;. Latitudes at the equator receive direct sunlight&#xA;year-round. Latitudes toward the poles receive sunlight at an oblique angle, which means that the same amount of&#xA;radiation is spread out over a larger area than at the equator.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Now let's try to find to what extent the amount of UVA radiations one receives depend on the latitude one is located:&lt;/p&gt;&#xA;&lt;p&gt;The 1995 study {1} looked at measured UVA in 4 cities in Chile with different latitudes (but some of them have different altitude, so this biases the comparison).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ayQKf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ayQKf.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wrXUg.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wrXUg.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As a reminder: UVA (315-400 nm); UVB (280-315 nm); UVC (100-280 nm). So only the table mentions UVA (the histogram only mentions UVB).&lt;/p&gt;&#xA;&lt;p&gt;I'd definitely be interested in more thorough studies.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;{1} Cabrera, Sergio, Salvador Bozzo, and Humberto Fuenzalida. &amp;quot;Variations in UV radiation in Chile.&amp;quot; Journal of Photochemistry and Photobiology B: Biology 28, no. 2 (1995): 137-142. &lt;a href=&quot;https://doi.org/10.1016/1011-1344(94)07103-U&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/1011-1344(94)07103-U&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="587" LastEditorUserId="587" LastEditDate="2021-09-06T20:55:29.227" LastActivityDate="2021-09-06T20:55:29.227" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22771" PostTypeId="1" CreationDate="2021-09-06T02:06:52.293" Score="4" ViewCount="563" Body="&lt;p&gt;I'm a complete beginner in fossil collection but from my understanding I should mostly look at sedimentary rocks for fossils. However the problem is that rocks that I see in real life are not the same as I read in textbooks.&lt;/p&gt;&#xA;&lt;p&gt;I'd like to accelerate my learning so I'm wondering if there is any app or games that show me photos of real life rocks and then ask me which kind of rock it is.&lt;/p&gt;&#xA;&lt;p&gt;If it helps to any degree, I live in the &amp;quot;Saint-Lawrence lowland&amp;quot; area and most of the fossils I expect to collect are from Ordovician period. Most stones are being washed by the river so the surface is kind of smooth.&lt;/p&gt;&#xA;" OwnerUserId="24386" LastEditorUserId="2958" LastEditDate="2021-09-06T12:25:10.550" LastActivityDate="2021-09-06T12:25:10.550" Title="Are there any rock recognition practices or games?" Tags="|rocks|fossils|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22774" PostTypeId="2" ParentId="22771" CreationDate="2021-09-06T05:10:51.347" Score="5" Body="&lt;p&gt;You could look at &lt;a href=&quot;https://play.google.com/store/apps/details?id=com.avicApps.geologyapp&amp;amp;hl=en_US&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt; and similar apps but they're more from the other side, you have a rock here's what you need to ask yourself to ID it. I don't use anything like that myself because I memorised the A2 rock identification flow chart we used to use at uni which was similar to that below only more complex. It sounds like you wouldn't benefit from something that complex as you aren't interested in the chemical range of formation for the individual types of the amphibole series minerals present etc... but the below should help you differentiate. You best bet for recognisable fossils are sandstone, limestone, mudstone, shale, and chalk.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FNkmg.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FNkmg.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2021-09-06T05:10:51.347" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22775" PostTypeId="1" CreationDate="2021-09-06T10:17:53.693" Score="5" ViewCount="68" Body="&lt;p&gt;I remember several years ago, the weather report on the VRT (Flemish national media) would show the temperature forecast of the coming days and it would also show the uncertainty on that temperature. I have included a picture of an example:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/G26cL.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G26cL.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The x-axis shows the days (in Dutch) and the y-axis the temperature. The gray area around the white predicted line is, I presume, the uncertainty. As you may notice, the magnitude of the uncertainty fluctuates with a period of a day. The uncertainty seems the smallest at the hottest time of the day, whereas at the coolest times, it seems the largest.&lt;/p&gt;&#xA;&lt;p&gt;Why is this? Is it because of an attractor in the meteorological system? Or is there another explanation?&lt;/p&gt;&#xA;" OwnerUserId="24389" LastActivityDate="2021-09-06T10:49:37.360" Title="Why does the magnitude of the uncertainty on temperature forecast fluctuate periodically" Tags="|meteorology|temperature|weather-forecasting|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22776" PostTypeId="2" ParentId="22775" CreationDate="2021-09-06T10:49:37.360" Score="3" Body="&lt;p&gt;This is typical of the winter weather in the Netherlands (I live there) and Belgium as well. In a period with maximum temperatures below 0, whether it's going to be cold or very cold in the night depends mainly on two things: the presence of any clouds which preserve the 'heat' from the day, and the presence of wind (especially from the south) which transports relatively warm air from elsewhere. During the day, the Sun can help with warming up (but not much, since it's not high up in the air), mitigating at least the 'clouds' factor.&lt;/p&gt;&#xA;&lt;p&gt;Here's a different graph, taken September 6th from &lt;a href=&quot;https://web.archive.org/web/20210906104700/https://www.weerplaza.nl/15daagse/&quot; rel=&quot;nofollow noreferrer&quot;&gt;a Dutch weather forecast site (archive link)&lt;/a&gt;. We currently have sort-of an Indian Summer and the uncertainties on the daily highs are comparable, and on the first few days even larger than the night temperatures.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8TWz9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8TWz9.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2958" LastActivityDate="2021-09-06T10:49:37.360" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22777" PostTypeId="1" CreationDate="2021-09-06T20:49:51.517" Score="6" ViewCount="2788" Body="&lt;p&gt;The following quotes seem to be contradictory.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;From &lt;a href=&quot;https://www.skincancer.org/risk-factors/uv-radiation/#:%7E:text=UVA%20is%20everywhere.,penetrate%20windows%20and%20cloud%20cover.&quot; rel=&quot;noreferrer&quot;&gt;skincancer.org&lt;/a&gt;, the amount of UVA radiations during daylight hours stays constant throughout the year:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;UVA accounts for up to 95 percent of the UV radiation reaching the earth. &lt;strong&gt;These rays maintain the same level of strength during daylight hours throughout the year.&lt;/strong&gt; This means that during a lifetime, we are all exposed to a high level of UVA rays. UVA can penetrate windows and cloud cover.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;From &lt;a href=&quot;https://www.washingtonpost.com/weather/2019/09/23/how-understanding-sun-angles-clarifies-character-seasons-their-weather/&quot; rel=&quot;noreferrer&quot;&gt;https://www.washingtonpost.com&lt;/a&gt;, the sun angle varies over the course of the year:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;We have seasons because &lt;strong&gt;the sun angle varies over the course of the year&lt;/strong&gt;, and it varies because the Earth's plane of rotation is tilted by about 23.5 degrees from the plane of its orbit around the sun.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;However, according to &lt;a href=&quot;https://www.biointeractive.org/sites/default/files/skincolorselection-educator-act.pdf&quot; rel=&quot;noreferrer&quot;&gt;biointeractive.org&lt;/a&gt; (&lt;a href=&quot;https://web.archive.org/web/20210906203902/https://www.biointeractive.org/sites/default/files/skincolorselection-educator-act.pdf&quot; rel=&quot;noreferrer&quot;&gt;mirror&lt;/a&gt;), the angle of the sun impacts how much UVA one receives (which means that how much UVA one receives depends on the day of the year and the lattitude):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;How do you explain the relationship between the UV Index and latitude? (In other words, why does UV&#xA;intensity change with latitude?)&lt;/p&gt;&#xA;&lt;p&gt;The answer has to do with the &lt;strong&gt;angle of Earth relative to the sun&lt;/strong&gt;. Latitudes at the equator receive direct sunlight year-round. Latitudes toward the poles receive sunlight at an oblique angle, which means that the same amount of radiation is spread out over a larger area than at the equator.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;These quotes confuse me as they seem to be contradictory to me (quote 1 contradicts quotes 2+3). Does the amount of UVA radiations one receives depend on the day ot the year? I don't mean the total amount accumulated over the day, but instead sometime during daylight.&lt;/p&gt;&#xA;" OwnerUserId="587" LastEditorUserId="587" LastEditDate="2021-09-07T01:57:44.167" LastActivityDate="2021-09-25T02:33:52.123" Title="Does the amount of UVA radiations one receives depend on the day ot the year?" Tags="|sun|seasons|uv-light|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22778" PostTypeId="2" ParentId="22777" CreationDate="2021-09-07T02:10:30.340" Score="8" Body="&lt;p&gt;UVA passes through the atmosphere without losing much intensity, so per quote one it's intensity doesn't change, nor does it's magnitude as a percentage of total &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_irradiance&quot; rel=&quot;nofollow noreferrer&quot;&gt;insolation&lt;/a&gt; vary, much, during the year (and what variance there is happens at source). Total ground level insolation intensity in &lt;span class=&quot;math-container&quot;&gt;$\mathrm{Wm^{-2}}$&lt;/span&gt; does change with latitude and seasonal angle of incidence though. As such while you're getting the same proportion of UVA in your sunlight year round you're getting less total solar radiation during the winter, so you get less UVA per hour on a winter day than in the summer, all else being equal.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="24481" LastEditDate="2021-09-25T02:33:52.123" LastActivityDate="2021-09-25T02:33:52.123" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22779" PostTypeId="2" ParentId="22777" CreationDate="2021-09-07T07:39:27.403" Score="6" Body="&lt;p&gt;Reddit user and &lt;a href=&quot;https://www.reddit.com/r/EarthScience/&quot; rel=&quot;nofollow noreferrer&quot;&gt;r/EarthScience&lt;/a&gt; mod &lt;a href=&quot;https://www.reddit.com/user/Halcyon3k&quot; rel=&quot;nofollow noreferrer&quot;&gt;Halcyon3k&lt;/a&gt; &lt;a href=&quot;https://redd.it/pj8j0c&quot; rel=&quot;nofollow noreferrer&quot;&gt;pointed&lt;/a&gt; me to the following visualization that nicely illustrates &lt;a href=&quot;https://earthscience.stackexchange.com/users/10735/ash&quot;&gt;Ash&lt;/a&gt;'s &lt;a href=&quot;https://earthscience.stackexchange.com/a/22778/587&quot;&gt;great answer&lt;/a&gt; on the fact that &amp;quot;total ground level insolation intensity in &lt;span class=&quot;math-container&quot;&gt;$\mathrm{Wm^{-2}}$&lt;/span&gt; does change with latitude and seasonal angle of incidence&amp;quot;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/trQSf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/trQSf.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(&lt;a href=&quot;https://www.macmillanhighered.com/BrainHoney/Resource/6716/digital_first_content/trunk/test/hillis2e/asset/img_ch41/c41_fig03.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;image source&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;Halcyon3k's explanation:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Solar energy is measured in watts per square meter but it will vary with the angle with respect to the sun.  This is best understood with [the image above].  It’s talking about latitude but this is the same thing that’s going on near sunrise vs noon vs near sunset. This is also a good interactive illustration of what’s going on: &lt;a href=&quot;https://engaging-data.com/solar-intensity/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://engaging-data.com/solar-intensity/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Also, from this 2001 study {1} that looked at the  UVA  irradiance  data  for  a  Southern  Hemisphere,  subtropical  site  (Toowoomba,  Australia,  27.6°S,  151.9°E):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AKLch.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AKLch.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;{1} Sabburg, J. and Parisi, Alfio and Wong, J. C. F. (2001). Effect of cloud on UVA and exposure to humans. Photochemistry and Photobiology, 74 (3), 412-416. ISSN 0031-8655. [&lt;a href=&quot;https://scholar.google.com/scholar?hl=en&amp;amp;as_sdt=0%2C48&amp;amp;q=Sabburg%2C+J.+and+Parisi%2C+Alfio+and+Wong%2C+J.+C.+F.+%282001%29.+Effect+of+cloud+on+UVA+and+exposure+to+humans.+Photochemistry+and+Photobiology%2C+74+%283%29%2C+412-416.+ISSN+0031-8655.+A&amp;amp;btnG=&quot; rel=&quot;nofollow noreferrer&quot;&gt;GScholar&lt;/a&gt;] [&lt;a href=&quot;http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.563.2942&amp;amp;rep=rep1&amp;amp;type=pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;PDF&lt;/a&gt;]&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="587" LastEditorUserId="24481" LastEditDate="2021-09-24T17:48:14.787" LastActivityDate="2021-09-24T17:48:14.787" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22780" PostTypeId="1" AcceptedAnswerId="22781" CreationDate="2021-09-07T10:59:28.653" Score="1" ViewCount="45" Body="&lt;p&gt;I'm newbie in filed of Geophysics science. I will be grateful if you could help me to understand this chart &lt;img src=&quot;https://i.postimg.cc/RhPS6QHG/112.jpg&quot; alt=&quot;Text&quot; /&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;what does line 12 or Line 11 mean? what about line15-14?&lt;/li&gt;&#xA;&lt;li&gt;How to identify the depths?&lt;/li&gt;&#xA;&lt;li&gt;what does other numbers mean in the chart (such as 40 or 13 on the chart)&lt;/li&gt;&#xA;&lt;li&gt;This diagram shows me the resistivity on the surface of earth of resistivity to depth of the earth?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="24392" LastActivityDate="2021-09-07T11:34:44.787" Title="How to interperet audio magnetotelluric results?" Tags="|geophysics|geomagnetism|electromagnetism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22781" PostTypeId="2" ParentId="22780" CreationDate="2021-09-07T11:34:44.787" Score="0" Body="&lt;ol&gt;&#xA;&lt;li&gt;These are acquisition lines id: each line provided a profile, the profiles are then joined to provide the current chart.&lt;/li&gt;&#xA;&lt;li&gt;you cannot, they have already been filtered, the depth are defined.&lt;/li&gt;&#xA;&lt;li&gt;40 and 13 along the lines is the resistivity values along that isoline&lt;/li&gt;&#xA;&lt;li&gt;It tells you the resistivity for the depth between 200 and 300 meters, as obtained via inversion of the collected measurments.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2021-09-07T11:34:44.787" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22784" PostTypeId="1" CreationDate="2021-09-07T22:20:26.373" Score="4" ViewCount="161" Body="&lt;p&gt;I've been doing a little geology research.  One of the topics that I noticed was the existence of &amp;quot;deformations&amp;quot; that appear in the rock layers if an earthquake has occurred.  Smaller deformations (on average) imply a smaller earthquake magnitude; larger deformations (on average) imply a larger earthquake magnitude.&lt;/p&gt;&#xA;&lt;p&gt;However, I have not been able to find a mathematical equation saying that a deformation of size X implies an earthquake magnitude of size Y, and vice versa.&lt;br /&gt;&#xA;Does such an equation exist?&lt;/p&gt;&#xA;" OwnerUserId="24398" LastEditorUserId="24398" LastEditDate="2021-09-07T23:37:19.903" LastActivityDate="2023-05-10T19:18:14.733" Title="Is There a Correlation Between Earthquake Magnitude and the Deformation Observed in the Rock?" Tags="|earthquakes|crust|mathematics|geologic-layers|continental-crust|" AnswerCount="5" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22785" PostTypeId="2" ParentId="22784" CreationDate="2021-09-08T02:19:36.633" Score="0" Body="&lt;p&gt;No fixed equation, partly because no two faults will be the same but largely because faults don't necessarily move in the same direction during a given earthquake as it did last time. In New Zealand the last really large, magnitude 8.2, earthquake in Wellington, in 1885, raised the harbour seabed and lowered the southern end of the Ruahine Ranges, historically speaking quakes have usually done the opposite. You can make an approximation of the average rate and direction of movement along a particular fault but you even if you had records of the exact timing and magnitude of every earthquake on that fault, and no-one has been around long enough for that, you couldn't generalise enough to have such an equation.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="10735" LastEditDate="2021-09-08T03:01:36.407" LastActivityDate="2021-09-08T03:01:36.407" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22786" PostTypeId="1" CreationDate="2021-09-08T05:41:48.787" Score="4" ViewCount="43" Body="&lt;p&gt;I found that Fe-oxides were usually not used for vectoring Fe mineral deposits of skarn type in geochemical exploration. As an indicator element, the common practice told us Fe-oxides should be the most important indicator for Fe mineral exploration. Is there someone who can give an explanation? In addition, which elements can be used for prospecting skarn Fe mineralization?&lt;/p&gt;&#xA;" OwnerUserId="11924" LastEditorUserId="2470" LastEditDate="2021-09-08T07:15:21.970" LastActivityDate="2021-09-10T07:51:50.793" Title="Why were Fe-oxides not usually used for finding skarn Fe ore deposits in geochemical exploration?" Tags="|geology|geochemistry|mineralogy|economic-geology|ore|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22787" PostTypeId="2" ParentId="22784" CreationDate="2021-09-08T07:44:05.297" Score="1" Body="&lt;p&gt;There is no mathematical equation relating geological deformation with earthquake magnitude.&lt;/p&gt;&#xA;&lt;p&gt;Different &lt;a href=&quot;https://en.wikipedia.org/wiki/Fault_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;faults&lt;/a&gt; move differently. Some move horizontally (strike-slip faults). Other move vertically (strike-dip faults), while others have a combination of the two (oblique slip faults).&lt;/p&gt;&#xA;&lt;p&gt;The friction along the fault, and resistance to movement, is also a significant factor in how much a fault will move. Additionally the location  of the earthquake and direction of the forces from the earthquake relative to the fault will affect the size of the movement along a fault.&lt;/p&gt;&#xA;&lt;p&gt;The size of movement along a fault may or may not be uniform.&lt;/p&gt;&#xA;&lt;p&gt;In addition to friction along a fault being a factor, the strength of protuberances along the fault will affect size of movement. Stronger protuberances can resist larger forces before they break. This can limit movement and it can determine the way a fault will move - smoothly or in an abrupt jerking manner.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-09-08T07:44:05.297" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22788" PostTypeId="2" ParentId="22784" CreationDate="2021-09-08T08:57:46.697" Score="1" Body="&lt;p&gt;You are probably thinking of &lt;a href=&quot;https://en.wikipedia.org/wiki/Pseudotachylyte&quot; rel=&quot;nofollow noreferrer&quot;&gt;pseudotachylite&lt;/a&gt; veins, which are interpreted as &amp;quot;fossil earthquakes&amp;quot; (among other things). To my knowledge, the first who tried to quantify some seismic parameters from pseudotachylite veins geometry was &lt;a href=&quot;https://doi.org/10.1111/j.1365-246X.1975.tb06195.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sibson (1975)&lt;/a&gt;. Notably, he determined a relationship between the vein thickness &lt;span class=&quot;math-container&quot;&gt;$a$&lt;/span&gt; and the displacement (slip) along the fault &lt;span class=&quot;math-container&quot;&gt;$d$&lt;/span&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$d = 436 a^2$&lt;/span&gt; (in cm)&lt;/p&gt;&#xA;&lt;p&gt;Later on he also discussed shear stress estimates. But going all the way back from stress to magnitude (i.e., energy) does not seem trivial. You could dig in the literature citing Sibson, there have probably been some works trying to improve this in the last 40 years.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit&lt;/strong&gt; &lt;span class=&quot;math-container&quot;&gt;$-$&lt;/span&gt; I just found one of such studies: &lt;a href=&quot;https://doi.org/10.1029/2020JB020694&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ferrand et al. (2020)&lt;/a&gt;. They found that pseudotachylite thickness scales with moment magnitude &lt;span class=&quot;math-container&quot;&gt;$M_W$&lt;/span&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9wP1w.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9wP1w.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Pseudotachylyte thickness &lt;span class=&quot;math-container&quot;&gt;$a$&lt;/span&gt; (data) and dynamic molten zone width &lt;span class=&quot;math-container&quot;&gt;$w$&lt;/span&gt; (calculations) vs. earthquake magnitude &lt;span class=&quot;math-container&quot;&gt;$M_W$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2021-09-08T09:38:20.287" LastActivityDate="2021-09-08T09:38:20.287" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22789" PostTypeId="2" ParentId="22784" CreationDate="2021-09-08T09:23:51.763" Score="2" Body="&lt;p&gt;Generalizing such relationships is, as suggested above, hard to impossible - but for well studied and understood systems such correlations have been observed. For instance there is a clear, and almost linear, &lt;a href=&quot;https://www.researchgate.net/publication/220019340_New_insights_into_the_local_crust_structure_of_Mt_Etna_volcano_from_seismological_and_morphotectonic_data/figures?lo=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;relationship between earthquake magnitude and displacement on Mt Etna.&lt;/a&gt; &lt;a href=&quot;https://pubs.geoscienceworld.org/ssa/bssa/article/74/6/2379/118679/Statistical-relations-among-earthquake-magnitude&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earlier work  with a global focus&lt;/a&gt; has observed similar relationships - but with, as would be expected, much more variance between regions.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2021-09-08T09:23:51.763" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22790" PostTypeId="1" CreationDate="2021-09-08T09:54:04.910" Score="1" ViewCount="133" Body="&lt;p&gt;Is it even possible? How much water would it take? Does the whole earth need to be flooded to reach that height?&lt;/p&gt;&#xA;" OwnerUserId="24401" LastEditorUserId="22648" LastEditDate="2021-09-09T06:53:01.787" LastActivityDate="2021-09-09T13:52:02.523" Title="Is it possible for a local flood to reach the heights of a mountain, say 7000 ft, and wash away a ship over 350 miles?" Tags="|meteorology|hydrology|flooding|" AnswerCount="1" CommentCount="0" ClosedDate="2021-09-09T19:36:17.570" ContentLicense="CC BY-SA 4.0" />
  <row Id="22791" PostTypeId="2" ParentId="22790" CreationDate="2021-09-08T10:29:41.357" Score="7" Body="&lt;p&gt;No it isn't possible. 7000 feet is 2133 metres. That water level would cover almost all the land mass of the globe, except for the highest mountains, like the Himalayas, the Andes etc. It would need at least twice the current volume of water in the ocean. Total melting of all icecaps would add less than 2% of the volume of water required.&lt;/p&gt;&#xA;&lt;p&gt;There might be limited local circumstances where you could wash a boat up several hundred metres up a hillside. There have been historical tsunamis that when channeled into narrow inlets have created waves of 500 metres, but the topography required to do this would only be found in very specific locations, very close to the coast. Larger tsunami waves have occurred in the geological past from volcanic events, major landslides or asteroid impacts, but it is unlikely that any event has occurred since mankind started building boats, that was large enough to create a 2000 metre wave, and that hasn't left clear geological evidence.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastEditorUserId="21672" LastEditDate="2021-09-09T13:52:02.523" LastActivityDate="2021-09-09T13:52:02.523" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22792" PostTypeId="1" CreationDate="2021-09-09T01:08:19.170" Score="3" ViewCount="687" Body="&lt;p&gt;I work outside in Florida, and the heat is sometimes unbearable. But if a breeze hits me, it makes it much more tolerable. There are some days where there is high heat and humidity, and a steady wind. Those days are much less uncomfortable than similar days with no wind. If we are trying to determine the apparent temperature, shouldn't wind speed be included in that calculation?&lt;/p&gt;&#xA;" OwnerUserId="24402" LastActivityDate="2021-09-14T07:15:17.987" Title="Why isn't wind speed considered when calculating a heat index?" Tags="|meteorology|temperature|wind|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22793" PostTypeId="1" CreationDate="2021-09-09T01:11:20.137" Score="2" ViewCount="579" Body="&lt;p&gt;We have all been told at some point that the Mariana Trench is the deepest place in the ocean, but is that really true? More than 80% of the world's oceans are unexplored, so couldn't there be a much deeper place?&lt;/p&gt;&#xA;" OwnerUserId="24387" LastEditorUserId="2470" LastEditDate="2021-09-09T05:29:08.343" LastActivityDate="2021-09-09T21:18:53.337" Title="Is Challenger Deep really the deepest place in the ocean?" Tags="|oceanography|geography|ocean-models|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22794" PostTypeId="2" ParentId="22792" CreationDate="2021-09-09T05:57:41.880" Score="1" Body="&lt;p&gt;All weather agencies record ‘&lt;a href=&quot;https://media.bom.gov.au/social/blog/1153/apparent-feels-like-temperature/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ambient temperature&lt;/a&gt;’— how warm the air is in the shade and sheltered from the wind. This is done by placing weather recording instruments in a &lt;a href=&quot;https://en.wikipedia.org/wiki/Stevenson_screen&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stevenson Screen&lt;/a&gt;. The height above ground that Stevenson Screens are placed is between 1.25 and 2 m (4 ft 1 in and 6 ft 7 in). By using this approach weather readings from around the world can be regarded being consistent and relatable.&lt;/p&gt;&#xA;&lt;p&gt;When weather forecasters produce a temperature forecast they try to produce a number that will be similar to what would be recorded by instruments in a Stevenson Screen.&lt;/p&gt;&#xA;&lt;p&gt;Knowing the effect humidity and wind has on how humans &lt;em&gt;&lt;strong&gt;feel&lt;/strong&gt;&lt;/em&gt; temperature most weather agencies also try to forecast the &lt;a href=&quot;https://en.wikipedia.org/wiki/Apparent_temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;apparent temperature&lt;/a&gt;. In colder parts of the world, agencies issue the forecast temperature and the wind chill factor. This isn't generally done for warmer regions, partly because predicting wind speeds and wind consistency can be difficult.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.abc.net.au/news/2017-08-09/what-is-apparent-temperature-and-how-is-it-useful/8784080&quot; rel=&quot;nofollow noreferrer&quot;&gt;What is apparent temperature and how do they measure what it really 'feels like' outside?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit 14 September 2021&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Apparent temperature forecast for the &lt;a href=&quot;https://www.weather.gov/akq/WBGT&quot; rel=&quot;nofollow noreferrer&quot;&gt;US&lt;/a&gt; and &lt;a href=&quot;https://graphical.weather.gov/sectors/louisianaLoop.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;Louisiana&lt;/a&gt;, by NOAA&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ag5Wd.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ag5Wd.png&quot; alt=&quot;US App Temp&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TVTkr.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TVTkr.png&quot; alt=&quot;Louisiana App Temp&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Apparent temperature &lt;a href=&quot;https://www.cwb.gov.tw/V8/E/W/County/County.html?CID=66&quot; rel=&quot;nofollow noreferrer&quot;&gt;forecasts&lt;/a&gt; for &lt;a href=&quot;https://www.cwb.gov.tw/V8/E/W/Town/Town.html?TID=6600600&quot; rel=&quot;nofollow noreferrer&quot;&gt;Taiwan&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LyfZ2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LyfZ2.png&quot; alt=&quot;Taiwan 1&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gdVWm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gdVWm.jpg&quot; alt=&quot;Taiwan 2&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-09-14T07:15:17.987" LastActivityDate="2021-09-14T07:15:17.987" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22795" PostTypeId="2" ParentId="17017" CreationDate="2021-09-09T06:14:13.280" Score="0" Body="&lt;p&gt;Geologic evidence for coral go back 500 million years.&#xA;Hawaiian islands are great examples as island chain, with Kauai 5.7 million and the youngest &amp;quot;Big Isle&amp;quot; at 110,000&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;Normally coral reefs take many millennia, but fast colonization time scales coral can proliferate pretty fast. Soft corals are the fastest growing. It typically takes coral 25 to 75 years to reach sexual maturity.&lt;/p&gt;&#xA;&lt;p&gt;Montipora capricornis (Leaf Plate) can also grow pretty quick....All in all it takes 1000 years to get a mature reef unrecognizable from natural ones 10,000+ years. Since corals build atop existing skeletons it's hard to gauge their age.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-09-09T06:14:13.280" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22796" PostTypeId="2" ParentId="22793" CreationDate="2021-09-09T12:57:16.573" Score="5" Body="&lt;p&gt;Short answer : yes&lt;/p&gt;&#xA;&lt;p&gt;Challenger Deep was discovered by (and named after) HMS Challenger in 1875. This was the world's first true oceanic scientific voyage. They took a LOT of soundings but compared to the size of the oceans they were merely lots of pin-pricks. So your doubt would have been well founded in the pre-satellite era.&lt;/p&gt;&#xA;&lt;p&gt;Nowadays bathymetry is measured using ship sonar, and satellites (typically radar to measure the sea surface to measure gravity). The latter would definitely identify potential candidates on a global scale - there aren't any.&lt;/p&gt;&#xA;" OwnerUserId="44" LastActivityDate="2021-09-09T12:57:16.573" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22797" PostTypeId="1" AcceptedAnswerId="22811" CreationDate="2021-09-09T13:27:27.290" Score="1" ViewCount="141" Body="&lt;p&gt;I am calculating changes in precipitation using the Delta method, wherein the relative changes are calculated thus:&lt;/p&gt;&#xA;&lt;p&gt;Delta change = (modelled Future climatology (2050s) - modelled historical climatology (1981-2010)) / modelled historical climatology (1981-2010))&lt;/p&gt;&#xA;&lt;p&gt;This Delta (or anomaly) data is added to the actual observations to produce a final bias corrected future projection for Precipitation using:&#xA;Future projection = Observed climatology (1981-2010) * (1 + Delta change).&lt;/p&gt;&#xA;&lt;p&gt;My problem is that there are some very large numbers being produced in the dataset (presumably due to dry areas having unrealistically large relative differences calculated between future and present). How can I account for this? They mention it in this paper: &lt;a href=&quot;https://www.nature.com/articles/s41597-019-0343-8&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/s41597-019-0343-8&lt;/a&gt; but I don't follow exactly what they did:&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;We note that in very dry areas (i.e. monthly historical precipitation&#xA;close to zero) relative changes could produce unreasonably large relative precipitation increases (e.g. Sahara&#xA;Desert). To avoid this, we made two adjustments: (1) we set a threshold of 0.1 mm month−1 both for current and&#xA;future GCM values, which prevents indetermination in Eq. 2; and (2) we truncate the top 2% of anomaly values&#xA;to the 98th percentile value in the empirical probability distribution for each anomaly gridded dataset&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="24395" LastActivityDate="2021-09-12T14:12:58.657" Title="How can I calculate the relative change in Precipitation using CMIP models without producing unrealistic results in Dry areas?" Tags="|climate-change|precipitation|climatology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22798" PostTypeId="2" ParentId="22793" CreationDate="2021-09-09T21:18:53.337" Score="2" Body="&lt;p&gt;All of the deepest locations are in &lt;a href=&quot;https://en.wikipedia.org/wiki/Subduction&quot; rel=&quot;nofollow noreferrer&quot;&gt;subduction&lt;/a&gt; zones/trenches, where one &lt;a href=&quot;https://en.wikipedia.org/wiki/Plate_tectonics&quot; rel=&quot;nofollow noreferrer&quot;&gt;tectonic plate&lt;/a&gt; is being dragged under another one. The greater the angle of subduction the greater the potential for depth of a trench associated with the subduction zone. The deepest zones have subduction angles greater than 70 degrees.&lt;/p&gt;&#xA;&lt;p&gt;The angle of subduction for the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mariana_Trench&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mariana Trench&lt;/a&gt; is the steepest known so far. Such angles only occur where &amp;quot;Earth's oceanic crust and lithosphere are old and thick and have, therefore, lost buoyancy&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;The oceanic crust of the Mariana Trench is from the Jurassic age and is among the oldest crusts on Earth.&lt;/p&gt;&#xA;&lt;p&gt;For an ocean trench to be deeper than the Mariana Trench its geology would need to be of similar age.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-09-09T21:18:53.337" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22799" PostTypeId="2" ParentId="22792" CreationDate="2021-09-09T23:32:45.003" Score="-2" Body="&lt;p&gt;The question is how one would &lt;em&gt;define&lt;/em&gt; a heat index, and one could do that in many different ways that would all make sense:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The way the heat index is defined is for people sitting in the shade where they are not exposed to wind. That's a reasonable approach as it is not an uncommon situation for people to be in such situations.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;One could define the heat index by taking wind into account. That too, would be a reasonable definition, but people are not all that often in places that have (i) shade, (ii) are exposed to ambient wind at the same time: If you're in a house or forest, you're generally not exposed to the ambient wind -- there might be a breeze, but its strength will very much depend on where exactly you currently are. If you're out where the wind will hit you, you're more likely than not also in the sun.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;In other words, defining a &amp;quot;heat index&amp;quot; involves making some subjective choices about what you think matters to the people who are interested in knowing what tomorrow's heat index will actually be.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2021-09-09T23:32:45.003" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22802" PostTypeId="2" ParentId="22786" CreationDate="2021-09-10T07:51:50.793" Score="5" Body="&lt;p&gt;Skarn is metamorphosed sedimentary rock, it's iron deposits are in the form of sulfides. This means two things;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;There almost certainly will be iron oxide contamination throughout the unit, at least I have never seen a sedimentary rock that didn't have staining from iron oxides. In my Earth Science classes we were always told that copper, and particularly iron oxide(s) were next to useless as diagnostic tools because tiny volumes of metal cause large and widespread colour signatures and sample contamination.&lt;/li&gt;&#xA;&lt;li&gt;The commercial iron ore deposits in skarn units are unusual in that they are normally sulfides rather than the more usual oxides, thus tracking oxides is not as useful as it would usually be.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;You're looking for sulfur based mineralisation so Gypsum may be diagnostic, you're also looking for areas of metal concentration so lower mobility metals like Molybdenum may also be useful.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2021-09-10T07:51:50.793" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22803" PostTypeId="1" CreationDate="2021-09-10T20:00:25.340" Score="14" ViewCount="1380" Body="&lt;p&gt;The US Northeast was hit surprisingly hard by Hurricane Ida, dumping a phenomenal amount of rain on the region, causing significant flooding and tornadic activity. I'm having difficulty understanding why the hurricane was able to travel so far inland with as much strength, particularly with regards to precipitation, given several mitigating factors:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Nearly 1,200 miles (1,900 km) of overland travel&lt;/li&gt;&#xA;&lt;li&gt;The intervening &lt;a href=&quot;https://en.wikipedia.org/wiki/Appalachian_Mountains&quot; rel=&quot;noreferrer&quot;&gt;Appalachian Mountain range&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.livescience.com/hurricane-ida-brown-ocean.html&quot; rel=&quot;noreferrer&quot;&gt;This article&lt;/a&gt; from LiveScience suggests that a &lt;a href=&quot;https://en.wikipedia.org/wiki/Brown_ocean_effect&quot; rel=&quot;noreferrer&quot;&gt;brown ocean effect&lt;/a&gt; occurred, which allowed Ida to retain strength further inland than normal due to the marshy areas north of Louisiana, but I would think that impact would've dissipated upon hitting the mountains.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, per &lt;a href=&quot;https://www.nbcnews.com/news/weather/map-here-s-how-much-rain-ida-dumped-northeast-n1278428&quot; rel=&quot;noreferrer&quot;&gt;several&lt;/a&gt; &lt;a href=&quot;https://www.northjersey.com/story/news/2021/09/02/rainfall-totals-nj-ida-tropical-storm-hurricane/5693060001/&quot; rel=&quot;noreferrer&quot;&gt;news&lt;/a&gt; &lt;a href=&quot;https://www.nbcboston.com/news/local/how-much-rain-did-you-get-from-ida-check-the-latest-totals/2482492/&quot; rel=&quot;noreferrer&quot;&gt;articles&lt;/a&gt; the rainfall amounts in the Northeast were peaking between 5-10 inches (130-260 mm). But somehow, this is more than totals seen &lt;a href=&quot;https://www.tennessean.com/story/news/local/2021/08/30/ida-warnings-and-alerts-middle-tennessee/5657600001/&quot; rel=&quot;noreferrer&quot;&gt;for&lt;/a&gt; &lt;a href=&quot;https://www.tennessean.com/story/weather/2021/09/01/rainfall-totals-hurricane-ida-nashville-middle-tennesse/5678999001/&quot; rel=&quot;noreferrer&quot;&gt;Tennessee&lt;/a&gt;, which saw around 5 inches (130 mm).&lt;/p&gt;&#xA;&lt;p&gt;Were there other sources that could've caused Ida's precipitation capacity to increase as it traveled more than 1,200 miles (1,900 km) overland?&lt;/p&gt;&#xA;" OwnerUserId="24410" LastEditorUserId="502" LastEditDate="2021-09-13T11:33:05.903" LastActivityDate="2023-06-30T09:38:14.290" Title="Why did Hurricane Ida have so much precipitation when it reached the Northeast?" Tags="|tropical-cyclone|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22804" PostTypeId="2" ParentId="22803" CreationDate="2021-09-11T02:47:53.770" Score="7" Body="&lt;p&gt;You're asking about several different aspects so let me try and get them in order.&lt;/p&gt;&#xA;&lt;p&gt;The slow drop off in rainfall is in fact because of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Brown_ocean_effect&quot; rel=&quot;nofollow noreferrer&quot;&gt;Brown Ocean Effect&lt;/a&gt; just a bigger one than we've seen before. Once Ida made landfall it was crossed one hot, saturated watershed after another and fed on their heat and moisture to extend its range. Because of how unseasonably wet and hot the land was Ida was, in effect, over open, tropical, water until it hit the Appalachian watershed divide.&lt;/p&gt;&#xA;&lt;p&gt;The Appalachians average only 910m (3000ft) so they don't block as much weather as the name &amp;quot;mountains&amp;quot; suggests they should, there is very little &lt;a href=&quot;https://en.wikipedia.org/wiki/Rain_shadow&quot; rel=&quot;nofollow noreferrer&quot;&gt;rain shadow&lt;/a&gt; effect across the range and then only around the higher peaks. They made very little difference to Ida just as they have to many other weather systems.&lt;/p&gt;&#xA;&lt;p&gt;The higher precipitation at the northeastern end of Ida's track was largely down to the fact that it finally lost it's brown ocean and started to lose strength and dump rain in a way that is more typical of a land bound tropical storm. It also ran into colder air that force it to lose yet more moisture.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="10735" LastEditDate="2021-09-12T00:58:47.147" LastActivityDate="2021-09-12T00:58:47.147" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="22805" PostTypeId="2" ParentId="22803" CreationDate="2021-09-11T05:03:39.793" Score="1" Body="&lt;p&gt;A hurricane is a system dynamic of moisture and warm air. As they go north, they get colder, and when they run out of energy, the moisture condenses in cooler climate. Precipitation is inevitable.&lt;/p&gt;&#xA;&lt;p&gt;An average thunderstorm cloud contains enough water drops to fill up approximately 275 million gallons, and a hurricane can store several billion.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastEditorUserId="502" LastEditDate="2021-09-13T11:32:57.077" LastActivityDate="2021-09-13T11:32:57.077" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22806" PostTypeId="1" CreationDate="2021-09-11T19:43:59.787" Score="1" ViewCount="314" Body="&lt;p&gt;I read in my physical geology textbook that sedimentary rocks cannot be dated using isotopic dating, because they are formed from fragments of other rocks and minerals, which if you were the subject individually to isotopic dating would give you a range of dates, many of which would be older than the sedimentary rock itself.&lt;/p&gt;&#xA;&lt;p&gt;My question is, because metamorphic rocks also form from different rocks and minerals (albeit from high heat and pressure, rather than erosion and weathering), how are you able to date them? The textbook also mentions that metamorphic rocks can be dated using isotopic dating, but that the results only tell us when metamorphosis occurred, but not the formation of the rock itself.&lt;/p&gt;&#xA;&lt;p&gt;Do the processes involved in the formation of metamorphic rocks cause new isotopes to be introduced in a way that doesn't happen with sedimentary rocks?&lt;/p&gt;&#xA;" OwnerUserId="17398" LastActivityDate="2021-09-14T12:14:17.253" Title="Isotopic dating of metamorphic rocks" Tags="|geology|mineralogy|metamorphism|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22807" PostTypeId="2" ParentId="22803" CreationDate="2021-09-12T01:08:56.343" Score="19" Body="&lt;p&gt;First, it's good to note that it really wasn't much of Ida that went that far... in terms of the strength of the low pressure (and the &lt;a href=&quot;https://earthscience.stackexchange.com/a/542/6298&quot;&gt;resultant wind&lt;/a&gt;), while &lt;a href=&quot;https://www.researchgate.net/figure/Land-use-land-cover-LULC-types-for-the-four-parish-study-area-in-southwestern_fig2_257129109&quot; rel=&quot;nofollow noreferrer&quot;&gt;the swampy waters in southern Louisiana&lt;/a&gt; may've helped it maintain category 4 strength for an extra few hours inland, it decayed rapidly soon after, &lt;a href=&quot;https://www.nhc.noaa.gov/archive/2021/graphics/AL092021/AL092021_5day_cone_no_line_and_wind_19.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;becoming a depression in Mississippi&lt;/a&gt;, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Extratropical_cyclone&quot; rel=&quot;nofollow noreferrer&quot;&gt;extratropical&lt;/a&gt; &lt;a href=&quot;https://www.wpc.ncep.noaa.gov/tropical/tropical_advisories.php?storm=IDA&amp;amp;adnum=26&amp;amp;dt=2021090115&amp;amp;status=posttrop&quot; rel=&quot;nofollow noreferrer&quot;&gt;near the Kentucky/West Virginia border&lt;/a&gt;.  By the time it passed through the northeast, it was just a 998-1000 mb low pressure with sustained winds of only 30-40 mph.  As a low pressure system it was quite pedestrian in even fairly recent history:&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;(Lower on the list = more intense low pressure), values are mostly peaks, at landfall if applicable&lt;/em&gt;&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th&gt;Storm&lt;/th&gt;&#xA;&lt;th&gt;When&lt;/th&gt;&#xA;&lt;th&gt;Pressure&lt;/th&gt;&#xA;&lt;th&gt;Sustained Winds&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;&lt;a href=&quot;https://w1.weather.gov/data/obhistory/KNYC.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Typical daily pressures&lt;/a&gt;&lt;/td&gt;&#xA;&lt;td&gt;&lt;/td&gt;&#xA;&lt;td&gt;~ 1005-1020 mb&lt;/td&gt;&#xA;&lt;td&gt;&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Tropical Storm Fay&lt;/td&gt;&#xA;&lt;td&gt;July 2020&lt;/td&gt;&#xA;&lt;td&gt;1000 mb&lt;/td&gt;&#xA;&lt;td&gt;45 mph&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;&lt;a href=&quot;https://www.wpc.ncep.noaa.gov/tropical/IDA/IDA_archive.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;Remnants of Ida&lt;/strong&gt;&lt;/a&gt;&lt;/td&gt;&#xA;&lt;td&gt;&lt;strong&gt;Sept 2021&lt;/strong&gt;&lt;/td&gt;&#xA;&lt;td&gt;&lt;strong&gt;998-1000 mb&lt;/strong&gt;&lt;/td&gt;&#xA;&lt;td&gt;&lt;strong&gt;30-40 mph&lt;/strong&gt;&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Tropical Storm Henri&lt;/td&gt;&#xA;&lt;td&gt;Aug 2021&lt;/td&gt;&#xA;&lt;td&gt;989 mb&lt;/td&gt;&#xA;&lt;td&gt;60 mph&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;2017 Nor'easter&lt;/td&gt;&#xA;&lt;td&gt;Feb 2017&lt;/td&gt;&#xA;&lt;td&gt;969 mb&lt;/td&gt;&#xA;&lt;td&gt;43 mph&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Hurricane Irene&lt;/td&gt;&#xA;&lt;td&gt;Aug 2011&lt;/td&gt;&#xA;&lt;td&gt;965 mb&lt;/td&gt;&#xA;&lt;td&gt;65 mph&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;2021 Nor'easter&lt;/td&gt;&#xA;&lt;td&gt;Feb 2021&lt;/td&gt;&#xA;&lt;td&gt;960 mb&lt;/td&gt;&#xA;&lt;td&gt;80 mph&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Hurricane Sandy&lt;/td&gt;&#xA;&lt;td&gt;Oct 2012&lt;/td&gt;&#xA;&lt;td&gt;946 mb&lt;/td&gt;&#xA;&lt;td&gt;80 mph&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;&lt;em&gt;Ida at Louisiana landfall&lt;/em&gt;&lt;/td&gt;&#xA;&lt;td&gt;&lt;em&gt;Aug 2021&lt;/em&gt;&lt;/td&gt;&#xA;&lt;td&gt;&lt;em&gt;930 mb&lt;/em&gt;&lt;/td&gt;&#xA;&lt;td&gt;&lt;em&gt;150 mph&lt;/em&gt;&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;&#xA;&lt;p&gt;Most tornadoes and many heavy rainfall events come outside of hurricanes, and a large number come from fairly weak lows.  They're both so much about how specific localized conditions lineup, not so much the strength of the low pressure itself.&lt;/p&gt;&#xA;&lt;hr&gt;&#xA;&lt;p&gt;Now, first to get a couple of the secondary questions out of the way:&lt;/p&gt;&#xA;&lt;p&gt;In regard to rain shadows, they're just as much about wind direction and surrounding factors.&#xA;In the fairly arid intermountain western US for example, storms come in with fairly limited total moisture as is (due to the cold east Pacific temperatures), then wring out quite a bit of what they have as widespread precipitation forced by its air rising over the Cascades and Sierras... but as important is that pre-storm wind directions from the northeast/east/southeast/south have very little access to water due to the basin nature of the whole region and large distances to water.  In comparison, most precipitation comes ahead of low pressures in the northeast because this is the wind direction:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hRP24m.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hRP24m.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As transitioning tropical cyclones work north from the Gulf (or regular lows work east from the Plains), they drop plenty of precipitation, and sure &lt;a href=&quot;https://d32ogoqmya1dw8.cloudfront.net/images/eslabs/weather/us_ppt_1971-2000.v2_1368.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;you can pick out&lt;/a&gt; some extra moisture is deposited from rising air on the windward side of the Appalachians... but the pre-storm fetch for the east coast is over &lt;a href=&quot;https://www.ospo.noaa.gov/data/sst/contour/namerica.cf.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;the warm Gulf-Stream&lt;/a&gt; of the western Atlantic, so moisture is well preserved... as the northeast coastal areas often finds out too well in the winter months when snow piles in from &lt;a href=&quot;https://en.wikipedia.org/wiki/Nor%27easter&quot; rel=&quot;nofollow noreferrer&quot;&gt;nor'easters&lt;/a&gt;.  Moisture profile isn't about where the center of the low pressure goes, but the flow around it.  In nor'easters, a just-offshore track tends to favor more snow not because a track over the Appalachians would steal the moisture, but because of how it maximizes the onshore flow most perpendicularly to the strongest temperature gradient to create the most lift (and because a track offshore means you're in the cold sector, a path over land means you spend more time in the warm sector (= perhaps not snow).  The low profile of the Appalachians and ability of air to flow around it from ample water areas of the Gulf, Atlantic, and even Great Lakes means there really isn't any great rainshadow in the eastern US.&lt;/p&gt;&#xA;&lt;p&gt;In terms of tornadoes, the overall count was &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_tornadoes_spawned_by_tropical_cyclones#2020%E2%80%932021&quot; rel=&quot;nofollow noreferrer&quot;&gt;fairly regular&lt;/a&gt; for tropical cyclones.&lt;/p&gt;&#xA;&lt;hr&gt;&#xA;&lt;p&gt;Now for rainfall... how much was there?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xXK9d.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xXK9d.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;sup&gt;&lt;sub&gt;&lt;em&gt;&lt;strong&gt;(remind me in a few months to update with a better graphic that the WPC produces for tropical cyclones)&lt;/strong&gt;&lt;/em&gt;&lt;/sub&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;Is that extraordinary?  Yes... and no... and yes... and no... and then very much yes!!!&lt;/p&gt;&#xA;&lt;p&gt;Those are some rainfall records listed up above, so it's certainly a notable amount in spots.&lt;/p&gt;&#xA;&lt;p&gt;However, certainly compared to rainfall when tropical cyclones stall further south, it's a &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_wettest_tropical_cyclones&quot; rel=&quot;nofollow noreferrer&quot;&gt;drop in the bucket&lt;/a&gt;.  In this very event, Ida, a few spots in Louisiana and Mississippi had &lt;a href=&quot;https://twitter.com/GCarbin/status/1432302397720862723&quot; rel=&quot;nofollow noreferrer&quot;&gt;nearly double the rain&lt;/a&gt; that even some of the harder hit spots in the northeast got.  Spots along the northeast Texas Gulf Coast got nearly &lt;em&gt;60 inches&lt;/em&gt; (1500 mm) of rain from &lt;a href=&quot;https://en.wikipedia.org/wiki/Hurricane_Harvey&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hurricane Harvey&lt;/a&gt; in 2017, and then another 40 inches (1000 mm) from weak &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_Storm_Imelda&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tropical Storm Imelda&lt;/a&gt; in 2019 (and looks like they could see another potential event next week).&lt;/p&gt;&#xA;&lt;p&gt;Still, one person's mountain is another person's molehill.  The northeast doesn't have particularly great permeable soil.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/o00Q2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/o00Q2.png&quot; alt=&quot;Enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;sub&gt;&lt;sup&gt;(&lt;a href=&quot;https://earthobservatory.nasa.gov/images/87220/soil-composition-across-the-us&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source NASA's Earth Observatory&lt;/a&gt;)&lt;/sup&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;And that's where there's soil.  The northeast is... kind of known as a &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_United_States_urban_areas#/media/File:USA-Urban-Areas.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;heavily urbanized area&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;So a comparable amount of rain in the New York metro versus most of Louisiana means more.&lt;/p&gt;&#xA;&lt;p&gt;But... what's most surprising to me is that, when you compare the rainfall maps to recent events overall... it really doesn't stand out much!!!&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Fs970.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Fs970.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sIJqz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sIJqz.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;A swath of like 5-8 inch rainfall in all three of the (at some point) hurricanes, each with a few higher inches spots.  Not off the charts.&lt;/p&gt;&#xA;&lt;p&gt;Yet, at least from what we saw on television from afar around the country, it seemed like this storm's (freshwater) flooding was comparably quite extreme.  (Though honestly the picture from the media often makes it seem like total widespread devastation when it's really not.  Many areas in southeastern Louisiana are quite reasonable, as were decent amounts of Houston in Harvey and south/central Florida in &lt;a href=&quot;https://en.wikipedia.org/wiki/Hurricane_Irma&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hurricane Irma&lt;/a&gt;.  It does seem harder to get a real feel of the true scope of an event from the media anymore ☹️)  But based upon the proliferation of awful videos of raging waters and collapsing basements around NYC and satellite images &lt;a href=&quot;https://www.npr.org/sections/pictureshow/2021/09/05/1034459845/satellite-photos-flooding-ida-new-jersey&quot; rel=&quot;nofollow noreferrer&quot;&gt;like these&lt;/a&gt;, and the list of different areas involved, it seems to have been fairly notable compared to most systems.&lt;/p&gt;&#xA;&lt;p&gt;So where does that leave us.  Get to the point, was it really that bad?!?&lt;/p&gt;&#xA;&lt;p&gt;The answers looks be yes.  For two reasons I can see/guess at.&lt;/p&gt;&#xA;&lt;p&gt;#1 is that the rainfall came two weeks after similar rainfall from Henri.  The soil was saturated, so less rainfall went into the soil.  The great Coast NOAA hurricane finder suggests only three times in past history has New York City had two tropical cyclones (or remnants) pass within 60 miles of NYC within a month... 1888, 1893, and  1985.  And the rainfall analyses from &lt;a href=&quot;https://www.wpc.ncep.noaa.gov/tropical/rain/henri1985filledrainwhite.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;1985-Henri&lt;/a&gt; and &lt;a href=&quot;https://www.wpc.ncep.noaa.gov/tropical/rain/gloria1985filledrainwhite.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gloria&lt;/a&gt; produced less rain and most of it further from the I-95 corridor.  So having two storms in quick succession (and additionally, &lt;a href=&quot;https://www.weather.gov/wrh/Climate?wfo=okx&quot; rel=&quot;nofollow noreferrer&quot;&gt;suggestions the NYC area was also about 4&amp;quot; above average in July&lt;/a&gt;), both happening to line up the heavy rain, made things tough.&lt;/p&gt;&#xA;&lt;p&gt;And #2 is the rainfall &lt;strong&gt;rate&lt;/strong&gt;.  Here are the greatest 1 hour rainfalls in modern history at Times Square (from Iowa State's dataset):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9zza2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9zza2.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Making &lt;a href=&quot;https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&amp;amp;q=155&amp;amp;network=NY_ASOS&amp;amp;zstation=LGA&amp;amp;var=max_p01i&amp;amp;threshold=100&amp;amp;hour=12&amp;amp;sdate=2000%2F01%2F01&amp;amp;edate=2000%2F12%2F31&amp;amp;month=all&amp;amp;dpi=100&amp;amp;_fmt=png&quot; rel=&quot;nofollow noreferrer&quot;&gt;other plots&lt;/a&gt; there's a range of results... &lt;a href=&quot;https://en.wikipedia.org/wiki/New_Brunswick,_New_Jersey&quot; rel=&quot;nofollow noreferrer&quot;&gt;New Brunswick&lt;/a&gt;/&lt;a href=&quot;https://en.wikipedia.org/wiki/Somerville,_Massachusetts&quot; rel=&quot;nofollow noreferrer&quot;&gt;Somerville&lt;/a&gt;, NJ, another badly hit area, similarly blew out their record... other spots weren't quite as bad but some still up flirting with records (as some did with Henri the week before), like Laguardia (2 of top 3 were in Ida) and Trenton (slight record)... whereas Philadelphia and Providence were nowhere on the list, showing it was a fairly narrow swath.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Why&lt;/em&gt; such heavy rainfall rates?&lt;/p&gt;&#xA;&lt;p&gt;Because it's getting well beyond a week since the event, data is a bit hard to come by on some key things (many of the best sites keep their data only a few hours to days because of the size... it's something I wish we'd focus on improving, but there's enough to piece together some things these days at least).  But I think it actually kind of relates back full circle in connection to the other topic touched on... tornadoes.  Intense tornadoes are quite rare in the northeast.  The central reason that both intense rain (like &amp;gt;2-3&amp;quot;) and tornadoes are scarcer up that way is that very intense deep convection is quite infrequent in the region because it's pretty rare to get instability/strong lift (hot moist air at the surface, cold air aloft, things like strong fronts [all giving the energy for rapidly rising air, allowing moisture to build faster/larger raindrop size]) and helicity (rotation of the winds with height which &lt;a href=&quot;https://en.wikipedia.org/wiki/Supercell&quot; rel=&quot;nofollow noreferrer&quot;&gt;allowing the storms to maintain intensity&lt;/a&gt;) to line up.  &lt;a href=&quot;https://www.spc.noaa.gov/exper/soundingclimo/&quot; rel=&quot;nofollow noreferrer&quot;&gt;SPC's sounding analysis&lt;/a&gt; shows that summer has some decent instability (CAPE) in the northeast, but lower helicity/deep layer shear, as the area is usually far removed from the jet stream and it's fairly rare to gets the enhancement a tropical cyclone can offer.  Whereas the ingredients were all reasonably in place for strong persisting updrafts = tornado potential and very heavy rainfall rates.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/waWav.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/waWav.png&quot; alt=&quot;Enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(&lt;a href=&quot;https://twitter.com/burgwx/status/1433567519810494465&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's a fantastic radar track video of Ida's US life&lt;/a&gt;... you can see the deep convection flare up brighter in the brighter yellow and reddish colors in a fairly tight band over NJ, also seen in the white deeper clouds that show up in the same area on &lt;a href=&quot;https://www.youtube.com/watch?time_continue=180&amp;amp;v=0HlhEB2GT88&amp;amp;&quot; rel=&quot;nofollow noreferrer&quot;&gt;satellite&lt;/a&gt;.)&lt;/p&gt;&#xA;&lt;p&gt;Why'd it come together like this?  Going to be hard to answer too confidently with a quick analysis with limited data.&lt;/p&gt;&#xA;&lt;p&gt;Was there extra moisture, perhaps from global warming?  Sea surface temperatures certainly are above normal in the region, as they are this year in much of the Atlantic basin.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/y7lpKm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/y7lpKm.png&quot; alt=&quot;Enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But a rough try at lining up NYC sounding data shows that while precipitable water level was very high at NYC, above the daily record, it wasn't miles off the charts for this time of year:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/D6hXXm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/D6hXXm.png&quot; alt=&quot;Enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;And plotting record dewpoints shows the surface moisture was also not extraordinary whatsoever (for even just fall months, which have lower absolute humidity than summer) at Central Park (&lt;a href=&quot;https://mesonet.agron.iastate.edu/sites/obhistory.php?station=NYC&amp;amp;network=NY_ASOS&amp;amp;metar=0&amp;amp;madis=0&amp;amp;year=2021&amp;amp;month=9&amp;amp;day=1&amp;amp;sortdir=asc&quot; rel=&quot;nofollow noreferrer&quot;&gt;obs&lt;/a&gt; vs &lt;a href=&quot;https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&amp;amp;q=155&amp;amp;network=NY_ASOS&amp;amp;zstation=NYC&amp;amp;var=max_dwpf&amp;amp;threshold=&amp;amp;hour=12&amp;amp;sdate=2000%2F01%2F01&amp;amp;edate=2000%2F12%2F31&amp;amp;month=fall&amp;amp;dpi=100&amp;amp;_fmt=png&quot; rel=&quot;nofollow noreferrer&quot;&gt;records&lt;/a&gt;) or Somerville (&lt;a href=&quot;https://mesonet.agron.iastate.edu/sites/obhistory.php?station=SMQ&amp;amp;network=NJ_ASOS&amp;amp;metar=0&amp;amp;madis=0&amp;amp;year=2021&amp;amp;month=9&amp;amp;day=1&amp;amp;sortdir=asc&quot; rel=&quot;nofollow noreferrer&quot;&gt;obs&lt;/a&gt; vs &lt;a href=&quot;https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&amp;amp;q=155&amp;amp;network=NJ_ASOS&amp;amp;zstation=SMQ&amp;amp;var=max_dwpf&amp;amp;threshold=&amp;amp;hour=12&amp;amp;sdate=2000%2F01%2F01&amp;amp;edate=2000%2F12%2F31&amp;amp;month=fall&amp;amp;dpi=100&amp;amp;_fmt=png&quot; rel=&quot;nofollow noreferrer&quot;&gt;records&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;Did the extra intensity from the existing rainfall / &amp;quot;brown ocean effect&amp;quot; over the deep south sustaining the storm a bit longer and giving it perhaps a bit larger of moisture envelope, shift the common ET-transition tornado zone caused by &lt;a href=&quot;https://journals.ametsoc.org/view/journals/wefo/19/2/1520-0434_2004_019_0411_mdiaaf_2_0_co_2.xml?tab_body=pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;dry slot interaction&lt;/a&gt; further up north than the more common mid-Atlantic/&lt;a href=&quot;https://en.wikipedia.org/wiki/Tennessee_Valley&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tennessee Valley&lt;/a&gt; areas?  Maybe?  But it would take a lot more to prove.&lt;/p&gt;&#xA;&lt;p&gt;Or was it just a small band happened to come together just right to produce a few supercells, as does happen on slight occasion (tornadoes are rare in the northeast, but not entirely unknown, &lt;a href=&quot;https://worldpopulationreview.com/state-rankings/tornado-alley-states&quot; rel=&quot;nofollow noreferrer&quot;&gt;usually having a modest regional outbreak every few years&lt;/a&gt; in areas like MD/PA/NJ/NY)?  Though it certainly was fairly &lt;a href=&quot;https://twitter.com/JakeCarstens/status/1433220767261593602&quot; rel=&quot;nofollow noreferrer&quot;&gt;above the typical&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Regardless, the models did absolutely remarkable with it, leading to very strong forecasts for both tornadoes and rainfall by the morning of:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MF8NFm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MF8NFm.png&quot; alt=&quot;Enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/s7go0m.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/s7go0m.png&quot; alt=&quot;Enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;both rare levels of risk, especially for the northeast (ditto success on &lt;a href=&quot;https://twitter.com/TAG42481/status/1432441352424468485&quot; rel=&quot;nofollow noreferrer&quot;&gt;NHC&lt;/a&gt; forecast skill).&lt;/p&gt;&#xA;&lt;p&gt;The extreme flood damage was quite clearly due in very large part to the excessive rain &lt;strong&gt;rates&lt;/strong&gt; and wet soils from recent storms.  What were the exact causes for those factors?  It's a complex task to unravel, and pinning it to one specific thing is often dubious meteorologically... just as there are a lot of factors that lead to any particular tornado outbreak or heavy rain event -- that's why they have historically been very hard to forecast until the advent of improved computer models.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2023-06-30T09:38:14.290" LastActivityDate="2023-06-30T09:38:14.290" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="22808" PostTypeId="2" ParentId="22806" CreationDate="2021-09-12T01:25:12.067" Score="1" Body="&lt;p&gt;The main objection with regard to sedimentary rock is that you can date the individual mineral grains with isotopic techniques but not when they were laid down together. All metamorphic rocks show some degree of new crystal growth whether through melting of the existing rock or additional material being deposited by transiting geothermal fluids, often both, it is those new crystals that can be dated. Therefore it depends on the mechanism(s) of metamorphosis occurred to determine if you can use isotopic ratios after metamorphosis and which techniques are viable. Rocks that are metamorphosed through the presence of nearby intrusions of igneous rock can be dated to that intrusion using isotopic dating of the resulting deposits. Metamorphic rocks with a high degree of new crystal growth can also be dated as the new minerals will have captured radio isotopes in known proportions as they grew. In the case of rocks that have undergone fluid metamorphosis we have to be more selective but can still take advantage of water soluble isotopes like Potassium being integrated into the rock during the process. Very lightly metamorphosed rocks are harder to date than those that have been more thoroughly altered.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="2470" LastEditDate="2021-09-12T10:22:54.950" LastActivityDate="2021-09-12T10:22:54.950" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22809" PostTypeId="1" CreationDate="2021-09-12T04:47:14.427" Score="5" ViewCount="90" Body="&lt;p&gt;&lt;sub&gt;&lt;a href=&quot;https://physics.stackexchange.com/q/676624/&quot;&gt;Crossposted&lt;/a&gt; at Physics SE&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;As the surface-ionospheric gap acts as a resonator for electromagnetic waves, it should have several harmonic values from the base, fundamental frequency of 7.83 Hz.&#xA;These are integer multiples, but there is a limit as to how high the frequency can go for it to have an effect, especially so for the Schumann resonance, as the gap between the lithosphere and ionosphere can change due to events in space, mainly the sun.&#xA;Hence, what is the maximum range of integer frequency values for the Schumann resonance?&lt;/p&gt;&#xA;" OwnerUserId="24416" LastEditorUserId="6129" LastEditDate="2021-11-12T18:54:31.347" LastActivityDate="2021-11-12T18:54:31.347" Title="Range of frequencies of the Schumann resonance?" Tags="|meteorology|atmosphere|geophysics|electromagnetism|upper-atmosphere|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="22810" PostTypeId="2" ParentId="8692" CreationDate="2021-09-12T11:11:28.273" Score="0" Body="&lt;p&gt;The data here are shown in terms of percent finer, which might be why the standard deviation is negative. Both the USACE Coastal Engineering Manual and Dean and Dalrymple show examples of standard deviation calculations using percent coarser statistics.&lt;/p&gt;&#xA;" OwnerUserId="24418" LastActivityDate="2021-09-12T11:11:28.273" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22811" PostTypeId="2" ParentId="22797" CreationDate="2021-09-12T14:12:58.657" Score="2" Body="&lt;p&gt;&lt;em&gt;(1) we set a threshold of 0.1 mm month−1 both for current and future GCM values&lt;/em&gt; = they masked out all grid cells with less than 0.1 mm month−1 precipitation. That way they're avoiding dividing by very small numbers in what you correctly identified as dry areas&lt;/p&gt;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;(2) we truncate the top 2% of anomaly values to the 98th percentile value in the empirical probability distribution for each anomaly gridded dataset&lt;/em&gt; = for each delta dataset (or anomaly gridded dataset) they set all grid cells with anomalies greater than the 98th percentile to the value of the 98th percentile. Presumably to catch any outliers that were not addressed with the masking of dry areas.&lt;/p&gt;&#xA;" OwnerUserId="19081" LastActivityDate="2021-09-12T14:12:58.657" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22812" PostTypeId="1" CreationDate="2021-09-13T10:12:34.437" Score="6" ViewCount="91" Body="&lt;p&gt;Looking at &lt;a href=&quot;https://earth.nullschool.net/#current/wind/isobaric/700hPa/overlay=temp/orthographic=84.04,30.85,447/loc=103.419,12.271&quot; rel=&quot;nofollow noreferrer&quot;&gt;earth.nullschool.net&lt;/a&gt; on &lt;code&gt;13.09.2021&lt;/code&gt; you can see that the temperature above the Himalayas appear warmer than the surroundings (at 700 hPa):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6ToDz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6ToDz.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;At the surface it looks more like one would expect with lower temperatures than the surroundings:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ESKao.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ESKao.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I'm guessing the explanation is connected to the difference in elevation. And that for some altitudes, temperatures closer to the surface (but not &lt;em&gt;at&lt;/em&gt; the surface) are higher.&#xA;Still, the same effect is not to be seen in other mountain areas in Europe and North America:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tfiAV.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tfiAV.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Any suggestions?&lt;/p&gt;&#xA;" OwnerUserId="15259" LastEditorUserId="15259" LastEditDate="2021-09-13T15:49:03.107" LastActivityDate="2021-09-13T15:49:03.107" Title="Why is the air above the Himalayas warmer than surrounding areas?" Tags="|meteorology|atmosphere|climate|temperature|altitude|" AnswerCount="0" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="22813" PostTypeId="1" CreationDate="2021-09-13T19:18:33.823" Score="1" ViewCount="67" Body="&lt;p&gt;I am doing a project in which I need data from all the globe of geomagnetic storms, I need to ask that from where I can find a list of all sites where I can find the data of geomagnetic storms easily or I would manually search about database of each country which provides the data?&lt;/p&gt;&#xA;" OwnerUserId="24422" LastActivityDate="2021-09-14T09:19:35.027" Title="Databases of all Astronomical Geomagnetic storms data" Tags="|solar-terrestrial-physics|storms|electromagnetism|magnetosphere|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22815" PostTypeId="2" ParentId="22792" CreationDate="2021-09-14T00:12:55.453" Score="0" Body="&lt;p&gt;Apparent temperatures help delineate thermal stress, or how hazardous to human health that thermal condition actually is. Which is why high ambient temperatures are often accompanied with a &amp;quot;wet-bulb temperature&amp;quot; (aka misery index). This better defines how hazardous the high temperature is to humans. On the low end, wind chill temperature does the same thing but for cold temperatures.&lt;/p&gt;&#xA;&lt;p&gt;Since thermal comfort is entirely subjective, it's not a measurable property that might carry any meaning.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2021-09-14T00:12:55.453" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22816" PostTypeId="1" CreationDate="2021-09-14T06:14:16.630" Score="3" ViewCount="235" Body="&lt;p&gt;I have calculated the &lt;span class=&quot;math-container&quot;&gt;$∂θ_\varepsilon/∂z$&lt;/span&gt; with 'Height', 'Latitude', 'Longitude' dimensions.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import numpy as np&#xA;import xarray as xr&#xA;from wrf import (getvar)&#xA;&#xA;eth = np.array(getvar(ncfile, &amp;quot;eth&amp;quot;, timeidx=time))&#xA;z = np.array(getvar(ncfile, &amp;quot;z&amp;quot;, timeidx=time, units=&amp;quot;km&amp;quot;)) &#xA;&#xA;deth = np.gradient(eth, axis=0)&#xA;dz = np.gradient(z, axis=0)&#xA;deth_dz = deth/dz&#xA;&#xA;dthdz = xr.DataArray(data=deth_dz, dims=['Height', 'Latitude', 'Longitude'])&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;I would like to plot the horizontal depth or thickness (in km) of the &lt;code&gt;dthdz&lt;/code&gt;.&#xA;It is a bit similar to &lt;a href=&quot;https://stackoverflow.com/questions/69009774/calculating-total-depth-of-a-variable&quot;&gt;this&lt;/a&gt; question. But when I do &lt;code&gt;dthdz.sum(dim='Height')&lt;/code&gt;, I get very low depth values. I just want to know where I'm doing it wrong. Thank you!&lt;/p&gt;&#xA;" OwnerUserId="23366" LastEditorUserId="24481" LastEditDate="2021-09-25T21:43:30.470" LastActivityDate="2021-09-25T21:43:30.470" Title="Calculating layer thickness in python" Tags="|meteorology|wrf|python|netcdf|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22817" PostTypeId="2" ParentId="22813" CreationDate="2021-09-14T09:19:35.027" Score="2" Body="&lt;p&gt;Could you be specific in your question as to what data you need on storms? Do you just need dates when storms occurred, or &lt;a href=&quot;http://isgi.unistra.fr/&quot; rel=&quot;nofollow noreferrer&quot;&gt;global geomagnetic index activity levels&lt;/a&gt;, or &lt;a href=&quot;https://intermagnet.github.io/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ground magnetic field measurements&lt;/a&gt;? Are you interested in the storm effects at Earth, or do you want space-borne measurements of solar activity?&lt;/p&gt;&#xA;&lt;p&gt;You can find lists of some basic info for the largest storms at &lt;a href=&quot;https://www.spaceweatherlive.com/en/auroral-activity/top-50-geomagnetic-storms.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;spaceweatherlive.com&lt;/a&gt; for example. For more detailed, or longer term lists there are &lt;a href=&quot;https://link.springer.com/article/10.1007/s11207-016-0897-y&quot; rel=&quot;nofollow noreferrer&quot;&gt;academic studies such as this&lt;/a&gt; (which may be behind a paywall, so contact you institute library if you have one, or email the authors as they'd likely be happy to send you a copy).&lt;/p&gt;&#xA;" OwnerUserId="14123" LastActivityDate="2021-09-14T09:19:35.027" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22818" PostTypeId="2" ParentId="22806" CreationDate="2021-09-14T12:14:17.253" Score="2" Body="&lt;p&gt;There are two ways (at least two I will discuss here) to date a metamorphic rock.&lt;/p&gt;&#xA;&lt;p&gt;The first is using an isochron. During a heating event, isotope ratios between different minerals (most often used are Rb-Sr and Sm-Nd) equilibrate, and the clock resets &lt;em&gt;among the different minerals&lt;/em&gt;. You get a Rb-Sr value for several different minerals and plot them up. Ideally, the slope gives you the age. Here's an example I just found off Google:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7A2B0.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7A2B0.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;http://dx.doi.org/10.1016/j.jafrearsci.2004.03.002&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://dx.doi.org/10.1016/j.jafrearsci.2004.03.002&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The rock has been metamorphosed (chloritised) and the newly formed minerals, when measured together, give you an age.&lt;/p&gt;&#xA;&lt;p&gt;The second method is to directly date single minerals. This is ideally better because you can pick up individual events. The first method only gives you the youngest recorded age (you'd hope). With individual minerals, especially good ones, you can individually date growth zones. Often this is done with U-Pb methods.  For example, here's a cathodoluminescence image of a zircon:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eIIEF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eIIEF.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;From this paper: &lt;a href=&quot;http://dx.doi.org/10.1093/petrology/egl033&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://dx.doi.org/10.1093/petrology/egl033&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where you can see that the core of a zircon mineral formed at around 1854 Ma, and the rim at around 1802 Ma. One way this could be interpreted is that the zircon originally crystallised from magma at 1854, and then during a metamorphic event at 1802 it grew bigger and that newly-formed rim records the metamorphic age.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-09-14T12:14:17.253" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22821" PostTypeId="1" CreationDate="2021-09-15T02:28:55.100" Score="1" ViewCount="16" Body="&lt;p&gt;As explained in the following document:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.google.com/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=&amp;amp;ved=2ahUKEwjww4al9v_yAhWAJTQIHRhPC5IQFnoECAsQAw&amp;amp;url=https%3A%2F%2Fwww.mdpi.com%2F2073-4433%2F7%2F9%2F116%2Fpdf&amp;amp;usg=AOvVaw09QtbhsPTQ4HLyl8yEexBG&quot; rel=&quot;nofollow noreferrer&quot;&gt;ELF Electromagnetic Waves from Lightning: The Schumann Resonances&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Upper-Atmosphere phenomena like Sprites and Elves can be recorded with extremely low frequency detectors. Hence, is it valid to assume than an increase in magnitude of the Schumann Resonance will lead to an increase in upper atmosphere phenomena intensity and frequency? After all, these are side-effects of the emission of electromagnetic radiation of thunderstorms.&lt;/p&gt;&#xA;" OwnerUserId="24416" LastEditorUserId="24416" LastEditDate="2021-09-15T21:19:21.250" LastActivityDate="2021-09-15T21:19:21.250" Title="Does an increase in SR lead to an increase in strength and intensity of ionospheric lightning?" Tags="|meteorology|solar-terrestrial-physics|electromagnetism|upper-atmosphere|ionosphere|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22823" PostTypeId="1" AcceptedAnswerId="22825" CreationDate="2021-09-15T08:22:04.690" Score="9" ViewCount="662" Body="&lt;p&gt;There are different reasons why a shoreline can change, including tides. But I've found a phenomenon that I can't explain.&lt;/p&gt;&#xA;&lt;p&gt;It happens in a Mediterranean beach called L'Esparrelló/La Caleta (&lt;a href=&quot;https://www.google.com/maps/place/Lesparrello/@38.4943722,-0.269224,251m/data=!3m1!1e3!4m5!3m4!1s0x0:0xf04d8921750fab62!8m2!3d38.4949188!4d-0.2676506&quot; rel=&quot;nofollow noreferrer&quot;&gt;link to Google Maps&lt;/a&gt;). The central part on this beach (maked in blue in the image below) is closed by two rock promontories (marked in red). The thing is, sometimes you can access to the beach without get into the water from point A but not from point B, and sometimes it's the opposite.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PCq44.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PCq44.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Sometimes one promontory closes the beach and sometimes it is closed by the other. Last summer, for instance, the Google Maps image was accurate: You could access the beach from point B, but not from point A. This summer, it's the opposite: It's not possible to access the beach from point B without getting wet, but it is possible from point A.&lt;/p&gt;&#xA;&lt;p&gt;I have not observed any change in the amount of sand.&lt;/p&gt;&#xA;&lt;p&gt;What explains this?&lt;/p&gt;&#xA;" OwnerUserId="24434" LastEditorUserId="22648" LastEditDate="2021-09-16T15:45:27.453" LastActivityDate="2021-09-16T15:45:27.453" Title="Why does this shoreline change this way?" Tags="|geomorphology|earth-observation|coastal|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22824" PostTypeId="1" CreationDate="2021-09-15T11:14:43.063" Score="1" ViewCount="107" Body="&lt;p&gt;Sentinel-5P satellite provides high-resolution data products on concentration levels for several atmospheric trace gases (NO&lt;sub&gt;2&lt;/sub&gt;, SO&lt;sub&gt;2&lt;/sub&gt;, O&lt;sub&gt;3&lt;/sub&gt;, and others), which are measured in mol/m&lt;sup&gt;2&lt;/sup&gt; within the total or tropospheric column.&#xA;I want to convert mol/m&lt;sup&gt;2&lt;/sup&gt; to μg/m&lt;sup&gt;3&lt;/sup&gt;. How can I do this?&lt;/p&gt;&#xA;" OwnerUserId="24436" LastEditorUserId="10735" LastEditDate="2021-09-15T11:37:45.957" LastActivityDate="2021-09-15T11:37:45.957" Title="convert mol/m2 to μg/m3" Tags="|geochemistry|air-pollution|environmental-protection|biogeochemistry|environmental-sensors|" AnswerCount="0" CommentCount="2" ClosedDate="2021-09-15T15:31:36.423" ContentLicense="CC BY-SA 4.0" />
  <row Id="22825" PostTypeId="2" ParentId="22823" CreationDate="2021-09-15T11:25:01.093" Score="12" Body="&lt;p&gt;Short version; the beach moves because the waves change.&lt;/p&gt;&#xA;&lt;p&gt;Long version; Beaches, and in fact entire bays, conform in shape and alignment to the prevailing wave patterns in the area. The exact magnitude and alignment of wave trains varies due to &lt;a href=&quot;https://en.wikipedia.org/wiki/Chaos_theory&quot; rel=&quot;noreferrer&quot;&gt;chaotically&lt;/a&gt; complex interactions between surface winds, subsurface currents, local seabed features, tide, larger basin geomorphology, season, surface temperature, humidity, other wave trains, etc... Different magnitude waves can preferentially pile sand up on the beach or pull it out into deeper water while wave trains on different alignments will push sand along the coast until the beach is parallel to the oncoming waves. On some coasts certain factors like strong prevailing winds and/or currents are so dominant that the wave alignment never varies noticeably during or between years. In more sheltered settings, like the Mediterranean, small changes in the dominant wind direction or the strength/direction of currents can make a noticeable difference to the alignment of the main wave patterns and the beaches that they form. Sand doesn't usually move very quickly, except during large storm events, so the change to the beach won't be noticeable over night but for those who don't visit a particular beach often the changes can be quite drastic and feel very sudden.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2021-09-15T11:25:01.093" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22826" PostTypeId="1" AcceptedAnswerId="22833" CreationDate="2021-09-15T14:22:27.937" Score="6" ViewCount="190" Body="&lt;p&gt;I have been brushing up on numerical methods for PDEs lately, and climate models provide such a rich set of models and ideas to practice with. &lt;strong&gt;However, I was a little confused about how academics can do research on large climate models--like the CESM, WRF, or other models produced by GDFL or NCAR--given the computational challenges of running these models?&lt;/strong&gt; These are global circulation models, or even limited regional atmospheric models with physics happening at multiple scales in the simulation. I was not sure if most institutions have setups to run these models locally, or is there some way to send a new model to NCAR or similar institute to test the accuracy, etc.&lt;/p&gt;&#xA;&lt;p&gt;To run large climate simulations requires supercomputers or large cluster resources, as well as delicate MPI and mapreduce operations. Since a lot of that model code is written in fortran, that just exacerbates the portability problem since there is less ability to &amp;quot;abstract&amp;quot; away some of this configuration in objects.&lt;/p&gt;&#xA;&lt;p&gt;Writing and running an individual component model or &amp;quot;parameterization&amp;quot; model for one of these larger models seems manageable. That task just requires the scholar to write something doable over one or a few machines. But then how can that same person test his/her model inside of one of the larger climate models?&lt;/p&gt;&#xA;&lt;p&gt;I have been doing some research on this, but have not found much. I found some descriptions of how these larger scale models are built from their development documentation. The code is available as open source, but something like the WRF has 1.5 million lines of code. So debugging it or customizing it to a different cluster seems pretty tough--though I don't have any person experience doing that with a climate model. I have also spoken with some climate folks at Caltech who are working on developing their own large scale climate models, but they could only explain the challenges that they faced with building a flexible meshing scheme, etc., The Caltech folks did not tell me about their experiences using the established large scale climate models.&lt;/p&gt;&#xA;&lt;p&gt;Hence, I figured I would ask the SE community.&lt;/p&gt;&#xA;&lt;p&gt;UPDATE:&#xA;As per some feedback below, I just wanted to explain why this question is posted on ES instead of the Academics.SE. The thought was that Academics.SE is a much more general site across all of academia and many people there don't know about the nuances of numerical computing and the computational setup that goes along with it. Hence, I posted the question on ES where the audience is more familiar with running these types of simulations. I recognize that this question is &amp;quot;soft&amp;quot; however it seemed relevant to others conducting ES and Atmospheric research--especially those who want to do research on this topic and come from other disciplines.&lt;/p&gt;&#xA;" OwnerUserId="15732" LastEditorUserId="2470" LastEditDate="2021-09-18T11:12:26.527" LastActivityDate="2021-09-19T17:21:42.463" Title="How do academics/institutions run large climate simulations given the computing challenges?" Tags="|climate-models|numerical-modelling|atmospheric-circulation|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22828" PostTypeId="1" CreationDate="2021-09-15T19:47:38.843" Score="4" ViewCount="100" Body="&lt;p&gt;I am calculating RH (%) using this well accepted equation:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$RH =e \times  \frac{100}{es(T)}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$e$&lt;/span&gt; is the vapour pressure and &lt;span class=&quot;math-container&quot;&gt;$es(T)$&lt;/span&gt; is the saturated vapour pressure at temperature &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I have observed &lt;span class=&quot;math-container&quot;&gt;$e$&lt;/span&gt; (ranging from 0&lt;span class=&quot;math-container&quot;&gt;$-$&lt;/span&gt;30 hPa).&#xA;I calculate &lt;span class=&quot;math-container&quot;&gt;$es$&lt;/span&gt; in R using one of the following equations (depending on the wet bulb temperature &lt;span class=&quot;math-container&quot;&gt;$Tw$&lt;/span&gt; in relation to zero (to account for vapour pressure over liquid or solid water)):&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;f.es1 &amp;lt;- function(T) 6.107 * exp(17.38 * T/(239. + T))    # Tw &amp;gt;= 0 &#xA;f.es2 &amp;lt;- function(T) 6.107 * exp(22.44 * T/(272.4 + T))   # Tw &amp;lt; 0&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;I have noticed that &lt;span class=&quot;math-container&quot;&gt;$RH$&lt;/span&gt; (using the first equation above) is extremely large in some cases (e.g., 4352.567). This is occurring when &lt;span class=&quot;math-container&quot;&gt;$e$&lt;/span&gt; is 0.6 and &lt;span class=&quot;math-container&quot;&gt;$es$&lt;/span&gt; is 0.01378497.&lt;/p&gt;&#xA;&lt;p&gt;I know I can scale the RH data to between 1:100, but I'm wondering if there is a better way of dealing with this? It is happening when &lt;span class=&quot;math-container&quot;&gt;$e$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$es$&lt;/span&gt; are extremely small. I'm guessing this is over really dry areas perhaps? Is there a better way of calculating &lt;span class=&quot;math-container&quot;&gt;$RH$&lt;/span&gt; for these places?&lt;/p&gt;&#xA;&lt;p&gt;This is some information about the dataset:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;1 variables (excluding dimension variables):&#xA;    short vap[lon,lat,time]   (Chunking: [2160,30,1])  &#xA;        standard_name: vapor_pressure&#xA;        long_name: vapor_pressure&#xA;        units: kPa&#xA;        add_offset: 0&#xA;        scale_factor: 0.01&#xA;        _FillValue: -32768&#xA;        missing_value: -32768&#xA;        description: Vapor Pressure&#xA;        dimensions: lon lat time&#xA;        coordinate_system: WGS84,EPSG:4326&#xA;&#xA; 3 dimensions:&#xA;    time  Size:12   *** is unlimited ***&#xA;        standard_name: time&#xA;        long_name: time&#xA;        units: days since 1900-01-01 00:00:00&#xA;        calendar: gregorian&#xA;        axis: T&#xA;    lon  Size:2160&#xA;        standard_name: longitude&#xA;        long_name: longitude&#xA;        units: degrees_east&#xA;        axis: X&#xA;    lat  Size:1080&#xA;        standard_name: latitude&#xA;        long_name: latitude&#xA;        units: degrees_north&#xA;        axis: Y&#xA;&#xA;5 global attributes:&#xA;    CDI: Climate Data Interface version 1.9.9rc1 (https://mpimet.mpg.de/cdi)&#xA;    Conventions: CF-1.6&#xA;    history: Wed Sep 15 14:21:54 2021: cdo remapcon,r2160x1080 TerraClimate19812010_vap.nc WCvap_terraclimate_1981_2010.nc&#xA;    method: These layers from TerraClimate were creating using climatically aided interpolation of monthly anomalies from the CRU Ts4.0 and Japanese 55-year Reanalysis (JRA-55) datasets with WorldClim v2.0 climatologies.&#xA;    CDO: Climate Data Operators version 1.9.9rc1 (https://mpimet.mpg.de/cdo)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Headings in the picture below:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;ind_e      = e&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;ind_T_1500 = Temperature (at 3pm)&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;ind_es     =    Saturated vapour pressure&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;ind_Rh1500 = Relative humidity calculated    for 3pm.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;ind_Tx     = Tmax&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;ind_Tn     = Tmin&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/s58kR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/s58kR.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is the updated dataframe (below). The e is slightly lower generally, but it still seems incorrect.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UXGj7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UXGj7.png&quot; alt=&quot;This is the updated dataframe&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24395" LastEditorUserId="24395" LastEditDate="2021-09-21T14:21:23.507" LastActivityDate="2021-09-21T14:21:23.507" Title="How can I deal with unrealistic Relative Humidities being calculated using vapour pressure and saturated vapour pressure?" Tags="|humidity|" AnswerCount="0" CommentCount="30" ContentLicense="CC BY-SA 4.0" />
  <row Id="22829" PostTypeId="2" ParentId="20045" CreationDate="2021-09-15T21:34:06.257" Score="0" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;We pick two locations on the same latitude&amp;quot;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Erathostenes used different latitude but same longitude to know Earth's circumference.&lt;/p&gt;&#xA;&lt;p&gt;If you do the experiment with the same latitude you'll get as Oscar Lanzi said :&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;the circumference ... of your latitude circle&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;And thus to know Earth true circumference you'll need to do the maths trick he said.&lt;/p&gt;&#xA;" OwnerUserId="24440" LastActivityDate="2021-09-15T21:34:06.257" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22830" PostTypeId="1" AcceptedAnswerId="22832" CreationDate="2021-09-15T23:30:39.637" Score="1" ViewCount="262" Body="&lt;p&gt;I'm developing an application where the user inputs latitude and longitude numbers in float type format.&lt;/p&gt;&#xA;&lt;p&gt;I have to validate that the format of the numbers are correct.&lt;/p&gt;&#xA;&lt;p&gt;My doubt is what is the maximun and minimum integer number on both latitude and longitude.&lt;/p&gt;&#xA;&lt;p&gt;Let me give an example:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;latitude:  &amp;lt;max/min&amp;gt;.666666&#xA;longitude: -&amp;lt;max/min&amp;gt;.666666&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;What are the correct &lt;code&gt;max&lt;/code&gt; and &lt;code&gt;min&lt;/code&gt; in both cases?&lt;/p&gt;&#xA;" OwnerUserId="24441" LastActivityDate="2021-09-16T11:34:09.837" Title="Maximum and minimum integer number of latitude and longitude" Tags="|coordinate-system|gps|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22831" PostTypeId="1" CreationDate="2021-09-16T05:38:31.123" Score="3" ViewCount="47" Body="&lt;p&gt;In reading some papers about the environmental impact of agricultural products such as crops and animal rearing, I am puzzled by the way land use is reported.  I understand that inputs such as energy, water, feed, etc are used up in the production of agricultural products, but land is not really &amp;quot;used up&amp;quot; - it is &amp;quot;occupied&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;As such, I expected land use measures to have a time unit, and be reported in some way corresponding to yield, as in area per mass per time - eg, it takes XXha to produce 1t of product / year.  However, the papers I've come across report land use in area per mass, with no time unit specified.  Is a time unit implicit here?  Or does land use refer to something different?&lt;/p&gt;&#xA;&lt;p&gt;Examples:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.researchgate.net/profile/Eric_Audsley/publication/265084052_Determining_the_environmental_burdens_and_resource_use_in_the_production_of_agricultural_and_horticultural_commodities_Defra_project_report_IS0205/links/544e841c0cf29473161be279.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Williams, Audsley, &amp;amp; Sandars (2006)&lt;/a&gt;: Table I and II - land use reported in ha/t&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.researchgate.net/profile/Sergiy-Smetana/publication/279514998_Meat_Alternatives_Life_Cycle_Assessment_of_Most_Known_Meat_Substitutes/links/58c067ba92851c2adfeb0ec4/Meat-Alternatives-Life-Cycle-Assessment-of-Most-Known-Meat-Substitutes.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Smetana et al (2015)&lt;/a&gt;: Table 2 - land use reported in m&lt;sup&gt;2&lt;/sup&gt;/kg&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.researchgate.net/profile/Hanna-Tuomisto-2/publication/215666764_Life_cycle_assessment_of_cultured_meat_production/links/0e59333858b59f32c3e49e3b/Life-cycle-assessment-of-cultured-meat-production.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tuomisto &amp;amp; de Mattos (2010)&lt;/a&gt;: Section 3 - land use reported in m&lt;sup&gt;2&lt;/sup&gt;/t&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="24442" LastEditorUserId="2470" LastEditDate="2021-09-16T15:43:52.510" LastActivityDate="2021-09-16T15:43:52.510" Title="How to interpret land use measures in environmental impact papers?" Tags="|measurements|agriculture|environmental-protection|land|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22832" PostTypeId="2" ParentId="22830" CreationDate="2021-09-16T11:34:09.837" Score="2" Body="&lt;p&gt;Latitude is easy: -90 to +90.&lt;/p&gt;&#xA;&lt;p&gt;Longitude can use one of two conventions: 0 to +360, or -180 to +180. You may want to handle both gracefully.&lt;/p&gt;&#xA;" OwnerUserId="39" LastActivityDate="2021-09-16T11:34:09.837" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22833" PostTypeId="2" ParentId="22826" CreationDate="2021-09-17T06:11:24.480" Score="5" Body="&lt;p&gt;This question is a little vague, with multiple aspects, but I shall do my best.&lt;/p&gt;&#xA;&lt;h2&gt;Computing resources&lt;/h2&gt;&#xA;&lt;p&gt;Some universities have their own clusters or supercomputers. But many countries also have regional or national facilities. For example, &lt;a href=&quot;https://www.archer2.ac.uk/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ARCHER2&lt;/a&gt; is the latest iteration of the UK's national supercomputer service. Small amounts of computing time are available for free to UK academics, but for large projects they must bid for it.&lt;/p&gt;&#xA;&lt;p&gt;It's rare for simulations to require something of the scale of ARCHER or ARCHER2; depending on the model being run, often a departmental or institutional system of just a few nodes may be adequate, especially if one isn't in a hurry.&lt;/p&gt;&#xA;&lt;h2&gt;Building code for different systems&lt;/h2&gt;&#xA;&lt;p&gt;So long as the code has been well-written, this is not as hard as it sounds. FORTRAN is reasonably well standardised (though some codes will require the use of a particular compiler), and MPI - despite its varied implementations - is too. And most modern supercomputers are massively parallel machines whose actual compute nodes are standard x64 servers, using CPUs such as Intel Xeons. So you can do a lot of development on a desktop PC before you try to build it somewhere big and expensive. The biggest differences between different systems tend to lie in the interconnectors (the high-speed, low-latency networking between nodes), but usually the system admins will have optimised an MPI installation for that system and made it available to users, so all the details of inter-process and inter-node communications are abstracted.&lt;/p&gt;&#xA;&lt;h2&gt;Making changes or improvements&lt;/h2&gt;&#xA;&lt;p&gt;As you've identified, for most people the key is to improve one small aspect at a time, such as a particular parametrisation. Once somebody has the standard code working, then if it is well written in a maintainable manner (not a given in the scientific world) then it is relatively straightforward for them to modify one aspect and test it. The hardest thing often is obtaining measurements or other data against which to validate the new version.&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="2470" LastEditDate="2021-09-18T11:11:59.397" LastActivityDate="2021-09-18T11:11:59.397" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="22834" PostTypeId="1" AcceptedAnswerId="22843" CreationDate="2021-09-17T07:42:19.953" Score="22" ViewCount="4709" Body="&lt;p&gt;In the 90's, there was a hole in the ozone layer as big as Antarctica. After the Montreal protocol was created, harmful CFCs were no longer emitted and the ozone layer problem subsided.&lt;/p&gt;&#xA;&lt;p&gt;I was just looking at the &lt;a href=&quot;https://ozonewatch.gsfc.nasa.gov/&quot; rel=&quot;noreferrer&quot;&gt;NASA data about the ozone layer&lt;/a&gt; and in September 2021, there seems to be a hole in the ozone layer as big as Antarctica. How can this still be the case? Why is there still a hole in the ozone layer?&lt;/p&gt;&#xA;" OwnerUserId="18434" LastEditorUserId="22648" LastEditDate="2021-09-17T13:00:38.423" LastActivityDate="2021-09-18T23:27:02.723" Title="Is there still a hole in the ozone layer?" Tags="|ozone|upper-atmosphere|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22835" PostTypeId="2" ParentId="4665" CreationDate="2021-09-17T09:09:00.860" Score="1" Body="&lt;p&gt;Let me add to the previous answer:&#xA;In mixing length theory the mixing length is often defined as the friction velocity &lt;span class=&quot;math-container&quot;&gt;${u_*}$&lt;/span&gt; divided by the vertical shear &lt;span class=&quot;math-container&quot;&gt;$\frac{dU}{dz}$&lt;/span&gt;. Both of these quantities can be measured more or less directly at different heights. In the absence of buildings/canopy the mixing length is to a first approximation proportional to &lt;span class=&quot;math-container&quot;&gt;${z}$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The displacement height &lt;span class=&quot;math-container&quot;&gt;${d}$&lt;/span&gt; is given by the height at which the mixing length approaches zero. The roughness length &lt;span class=&quot;math-container&quot;&gt;${z_0}$&lt;/span&gt; is, however, still needed to match the wind speed profile.&lt;/p&gt;&#xA;" OwnerUserId="24445" LastEditorUserId="-1" LastEditDate="2021-09-22T12:04:20.037" LastActivityDate="2021-09-22T12:04:20.037" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22836" PostTypeId="2" ParentId="22834" CreationDate="2021-09-17T09:41:28.390" Score="25" Body="&lt;p&gt;Some countries are still illegally using banned chlorofluorocarbons (CFCs).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;In 2018, high levels of banned chlorofluorocarbons were detected in the atmosphere that were eventually traced to China&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Other reasons include &lt;a href=&quot;https://www.space.com/giant-ozone-hole-antarctica-climate-change&quot; rel=&quot;noreferrer&quot;&gt;climate change&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The concentrations of the damaging substances in the atmosphere have leveled off since the protocol came into force and are slowly decreasing, providing the foundation for the layer's gradual healing. But worsening climate change is now slowing down the recovery.&lt;/p&gt;&#xA;&lt;p&gt;While temperatures at the planet's surface are increasing, the stratosphere, where the protective ozone shield resides, is cooling down. The stratosphere, the layer of Earth's atmosphere about 6.5 to 30 miles (10 to 50 kilometers) in altitude, is where the so-called polar stratospheric clouds form in winter. Scientists know today that these clouds provide the perfect chemical environment for the damaging chlorine and bromine-based substances to do their destructive work. They also know that the colder the temperature of the stratosphere, the more polar stratospheric clouds tend to form.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Sometimes the ozone hole is small because there are no polar stratospheric clouds and sometimes, when there are many, it tends to be bigger.&amp;quot; &amp;quot;With more polar stratospheric clouds, chlorine and other harmful substances can work more effectively and cause more damage even if their concentrations are decreasing.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;As a &lt;a href=&quot;https://theconversation.com/explainer-what-is-the-antarctic-ozone-hole-and-how-is-it-made-9202&quot; rel=&quot;noreferrer&quot;&gt;further explanation&lt;/a&gt;,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Halogenated ODS are effectively inert in the lower atmosphere. The overturning motions associated with warming and cooling of airmasses in the lower atmosphere allows some of the ODS to be transported into the stratosphere. The substances are then broken down by ultraviolet light and form stable halogenated “reservoir” compounds, which by themselves do not strongly affect ozone.&lt;/p&gt;&#xA;&lt;p&gt;The main problem arises when the reservoir compounds are further altered to create halogenated “reactive” radicals. This is done through processes that largely take place on the surfaces of tiny stratospheric aerosol particles. These reactions make the by-products of the ODS more potent for ozone destruction.&lt;/p&gt;&#xA;&lt;p&gt;The amount of particles taking part in this process is significantly enhanced in Antarctica over winter. This is because of the presence of Polar Stratospheric Clouds (PSCs) in the lower stratosphere.&lt;/p&gt;&#xA;&lt;p&gt;PSCs are made up of tiny particles made up primarily of nitric acid and water vapour, and require a temperature of around -80°C or colder to form. In winter, a vortex of air forms in the stratosphere over Antarctica. Within the vortex, air circulates with minimal mixing with the rest of the atmosphere. This drives strong cooling of the lower stratosphere and creates the conditions favourable for PSC formation.&lt;/p&gt;&#xA;&lt;p&gt;When spring comes, the halogens released by the PSCs are broken down by sunlight. The resulting free chlorine and bromine atoms destroy ozone before being cycled back into halogen radicals. The presence of sunlight begins the cycle again.&lt;/p&gt;&#xA;&lt;p&gt;Overall, the reaction cycle destroys many ozone molecules for each chlorine and bromine atom present. PSC formation enhances the cycle as it removes certain nitrogen compounds from the atmosphere. These compounds would otherwise reduce the overall amount of halogenated radicals present.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;The &lt;a href=&quot;https://www.abc.net.au/news/2021-09-17/earth-ozone-layer-hole-larger-than-antarctica/100469328&quot; rel=&quot;noreferrer&quot;&gt;latest opinion&lt;/a&gt;, is that,&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;while the ozone layer is beginning to recover, it's likely to take until the 2060s for the ozone-depleting substances used in refrigerants and spray cans to completely disappear from the atmosphere.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="22648" LastEditDate="2021-09-17T16:37:41.413" LastActivityDate="2021-09-17T16:37:41.413" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="22841" PostTypeId="2" ParentId="13416" CreationDate="2021-09-18T16:10:26.950" Score="1" Body="&lt;p&gt;Unlike fat under the skin of animals (&amp;amp; humans) there is no worldwide layer or layers of hydrocarbons below the surface of the Earth.&lt;/p&gt;&#xA;&lt;p&gt;Crude oil, and other hydrocarbons, occurs in distinct deposits at various locations globally. At some locations some deposits overlie each other and at others there may be just one layer but at many other locations there are no deposits of hydrocarbons beneath them, just various deposits of rock. All these scenarios occur naturally.&lt;/p&gt;&#xA;&lt;p&gt;Most of the Earth does not have a layer of hydrocarbons.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-09-18T16:10:26.950" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22843" PostTypeId="2" ParentId="22834" CreationDate="2021-09-18T23:27:02.723" Score="21" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Why is there still a hole in the ozone layer?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;To some extent, there most likely will always be an area over Antarctica with reduced stratospheric ozone content in late Southern Hemisphere winter. (I wrote &amp;quot;always&amp;quot;. Read that as meaning for the next several millions of years.) The issues is how long that annual ozone hole exists, how large that ozone hole becomes, how deeply depleted that ozone hole is, and (most importantly) what that means for the world at large. The reason it will continue to exist to some extent is that volcanos can inject ozone-deleting chemicals directly into the stratosphere.&lt;/p&gt;&#xA;&lt;p&gt;However, right now, the worst of the ozone-deleting chemicals in the stratosphere are chemicals created by humans. Many of those chemicals will remain in the atmosphere for decades after production of them is ceased. For example, the graph below depicts the amount of trichlorofluoromethane (aka Freon-11, and other names) in the atmosphere:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5on5F.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5on5F.png&quot; alt=&quot;Concentration of trichlorofluoromethane in the atmosphere from 1978 to 2021&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;From the graph, it's apparent that the concentration peaked around 1993 and has been slowly declining since then. It has been almost 30 years since the production of trichlorofluoromethane has been banned, and yet the levels remain well above the late 1970s level. Ozone-depleting chemicals such as trichlorofluoromethane take decades to centuries to leave the atmosphere, even in the case that production has been completely eliminated. Trichlorofluoromethane, for example has an atmospheric half life of 40 to 100 years, depending on which article one reads. The Montreal Protocol does nothing to address the long-lived nature of those ozone-depleting substances. Once those substances get into the atmosphere, they are going remain in the atmosphere for a long time.&lt;/p&gt;&#xA;&lt;p&gt;The Montreal Protocol did not tell countries to immediately stop producing ozone-depleting substances and to collect and destroy all known stockpiles of ozone-depleting substances. What it did do was to issue a phased shutdown of production of those ozone-depleting substances. Some such as halon were phased out more slowly than freon. Others such as carbon tetrachloride have not yet been completely phased out.&lt;/p&gt;&#xA;&lt;p&gt;From the above graph, there was a slight stall in the decline starting around 2013 or so. This apparently was illegal production in Asia, later chased down to China. But this was a slight stall. The important thing to read from the graph is that it will take a long time for those human-created ozone-depleting chemicals to vanish.&lt;/p&gt;&#xA;&lt;p&gt;To make matters worse, the replacements for substances such as Freon and Halon also tend to be ozone-depleting substances. They're not nearly as bad in terms of ozone depletion potential as Freon and Halon, but they still are ozone-depleting substances.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2021-09-18T23:27:02.723" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22844" PostTypeId="1" CreationDate="2021-09-19T08:50:22.533" Score="1" ViewCount="57" Body="&lt;p&gt;I would like to know if using variables (ex: sea surface temperature, precipitation, etc.) from two CMIP6 climate models to produce a species/niche distribution model is an accepted practice and won’t affect the produced model validity?  If it’s accepted, are there any limitations that should be considered (ex. variables should come from models of equal climate sensitivity, have the same model components, etc)?&lt;/p&gt;&#xA;" OwnerUserId="24466" LastActivityDate="2021-09-19T08:50:22.533" Title="Using variables from different CMIP6 models" Tags="|meteorology|models|climate-models|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22845" PostTypeId="2" ParentId="22826" CreationDate="2021-09-19T17:21:42.463" Score="3" Body="&lt;p&gt;Another UK perspective here to supplement Semidiurnal Simon’s answer (which reflects my experience too).&lt;/p&gt;&#xA;&lt;p&gt;The UK research community is dominated by a single family of models known collectively as the Unified Model.  The code for these is owned by the UK's national weather and climate modelling center, the Met Office, and used gratis under license by academics.  That license gives academics access to repositories of model source code and experiment setups shared across the MO and academic community.  Simon mentioned ARCHER2, which is shared by the academics across all disciplines, but the Met Office also provides &lt;a href=&quot;https://www.metoffice.gov.uk/research/approach/collaboration/jwcrp/monsoon-hpc&quot; rel=&quot;nofollow noreferrer&quot;&gt;Monsoon&lt;/a&gt; specifically for atmospheric modelling collaborations with the academic community.&lt;/p&gt;&#xA;&lt;p&gt;Because the MO is an operational forecast center, they put a &lt;em&gt;lot&lt;/em&gt; of effort into making sure the code and support software run efficiently and reliably, so what academics have access to is pretty battle hardened.  But the academic side also has &lt;a href=&quot;https://cms-helpdesk.ncas.ac.uk&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCAS-CMS&lt;/a&gt;, whose job it is to make sure the model works on machines like ARCHER2 for the whole community.  All in all there’s a good level of national support for this model on these machines, and when I send a student on the training course for the model they can be running climate simulations on that hardware within 30 minutes of arriving.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;something like the WRF has 1.5 million lines of code. So debugging it or customizing it to a different cluster seems pretty tough&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Well, the UM has about 1.3 million lines of code and I’d estimate that I know about 15% of that code very very well (mainly a particular area of science) and the rest of it barely at all.  When I encounter bugs they’re almost always because of the thing that I’ve just changed or something closely related in areas of the code I know well.  When bugs lead into other parts of the model, it’s usually best to go and ask someone who knows about those areas rather than digging too hard yourself.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Writing and running an individual component model or &amp;quot;parameterization&amp;quot; model for one of these larger models seems manageable... But then how can that same person test his/her model inside of one of the larger climate models?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Yes, new parameterizations are often developed separately from the full climate model before being added to it.  But the longer a parameterization is developed in isolation the more likely it is that it will be conceptually or technically incompatible with the full model.  The trick is knowing early on that you want to couple it into the larger model later and to design your parameterization accordingly.  In my experience, however modular we aspire to make these models, it can still be quite a pain to couple in parameterization code that’s had a well-established, independent life outside of the climate model.  In general though, this is where the shared code repositories and an active community are really useful.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Since a lot of that model code is written in fortran, that just exacerbates the portability problem since there is less ability to &amp;quot;abstract&amp;quot; away some of this configuration in objects.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I remember years ago, as a student, a computer scientist friend of mine avoided doing an industry placement at a climate modelling center because he had such a low opinion of their software.  &amp;quot;It's so basic and boring&amp;quot;, he said, &amp;quot;They just use Fortran!&amp;quot;  But those same things that are off-putting to a computing student are beneficial to the largely self-taught programmers (i.e., physical scientists) who are working with these models.  Fortran is a fairly straightforward and safe language to learn and use, with relatively few concepts and gotchas.  Compare that with OOP paradigms, which are hard to use well without significant training.&lt;/p&gt;&#xA;&lt;p&gt;But those are more comments on the portability of the programmers than of the programs.  As Simon mentions, the difficult bits of getting a climate model running on new hardware (big or small) tend to be handled by the support staff of that hardware rather than the academic researchers themselves.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2021-09-19T17:21:42.463" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22846" PostTypeId="1" CreationDate="2021-09-20T02:34:32.090" Score="4" ViewCount="261" Body="&lt;p&gt;I need help in explaining the commercial viability of this potential Tantalum lab test result from Africa.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Eu9IY.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Eu9IY.png&quot; alt=&quot;Lab Test Report&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24474" LastEditorUserId="2470" LastEditDate="2021-09-20T22:22:02.277" LastActivityDate="2021-09-23T01:31:31.733" Title="Interpreting Prospecting Ore Test Result" Tags="|measurements|mining|economic-geology|resources|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22847" PostTypeId="2" ParentId="22846" CreationDate="2021-09-20T08:00:16.787" Score="5" Body="&lt;p&gt;One lab result does not an orebody make.&lt;/p&gt;&#xA;&lt;p&gt;In terms of &lt;em&gt;economic potential&lt;/em&gt; nothing can be ascertained from data in the question.&lt;/p&gt;&#xA;&lt;p&gt;When it comes to minerals and economics there are two terms that need to known and most people don't realize the difference.&lt;/p&gt;&#xA;&lt;p&gt;A mineral &lt;strong&gt;resource&lt;/strong&gt; is simply a deposit of a particular mineral, usually associated with a particular metal or metals, or other geological commodity, such as diamonds. &lt;em&gt;No economic significance&lt;/em&gt; is attached to a &lt;strong&gt;resource&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;An &lt;strong&gt;reserve&lt;/strong&gt; is a resource (mineral deposit), or part of a resource, that has been fully and competently assessed and evaluated by geologists and mining engineers and deemed to be economic. It can be mined for a profit.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, the terms &lt;strong&gt;ore&lt;/strong&gt; and &lt;strong&gt;orebody&lt;/strong&gt; only apply to geological &lt;strong&gt;reserves&lt;/strong&gt; - those parts of a mineral deposit that are &lt;em&gt;economic&lt;/em&gt; to mine. If there is no evaluation proving economic viability or an evaluation proves a body/deposit is uneconomic it cannot be called an orebody, or referred to as ore. It's just a deposit of mineralization. Should the price for the commodity increase in the future an additional evaluation, then, might result in it being reclassified as a reserve an hence and orebody.&lt;/p&gt;&#xA;&lt;p&gt;Any evaluation of a mineral deposit must consider:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the style of mineralization, the size of the resource, its shape,&#xA;orientation (whether it is nearly flat or nearly vertical - its dip),&lt;/li&gt;&#xA;&lt;li&gt;its true thickness (perpendicular to the dip) as opposed to apparent&#xA;thickness,&lt;/li&gt;&#xA;&lt;li&gt;whether it is one large deposit or a number of smaller deposits and&#xA;their proximity to each other,&lt;/li&gt;&#xA;&lt;li&gt;whether there are differences between proximal deposits,&lt;/li&gt;&#xA;&lt;li&gt;the amount of a particular metal or metals, or diamonds or other&#xA;commodity,&lt;/li&gt;&#xA;&lt;li&gt;the mining method or methods to be used,&lt;/li&gt;&#xA;&lt;li&gt;the amount of material that can be mined from the deposit&#xA;(mining recovery),&lt;/li&gt;&#xA;&lt;li&gt;the competency of the orebody and surrounding host rock and its&#xA;implication for ground conditions, mining method and safety,&lt;/li&gt;&#xA;&lt;li&gt;the presence and quantities of &lt;a href=&quot;https://en.wikipedia.org/wiki/Gangue&quot; rel=&quot;nofollow noreferrer&quot;&gt;gangue&lt;/a&gt; minerals and deleterious&#xA;minerals (such as very minor or nuisance amounts of radioactive metals in a copper deposit, or copper in a gold deposit - minerals that could affect the metallurgical recovery),&lt;/li&gt;&#xA;&lt;li&gt;proximity to a mineral processing plant for that style of&#xA;mineralization,&lt;/li&gt;&#xA;&lt;li&gt;the amount of minerals and thus metals that can be extracted by the&#xA;processing plant (processing or metallurgical recovery),&lt;/li&gt;&#xA;&lt;li&gt;disposal of waste mineralization and eventual site rehabilitation.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The information presented in the question is simply an overall tabulation of minerals and the proportion of each mineral. There is no indication whether the data is for one sample or one deposit or one site. It does not specify the amount of each specific metal of interest there is in the sample, or deposit.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Garnet&quot; rel=&quot;nofollow noreferrer&quot;&gt;Garnet&lt;/a&gt; is a silicate mineral that is generally used as an abrasive. Given it is only 6 percent of the quantity it is most likely not economic. It could indicate potential wear issues during the mining phase of operations with a higher than usual rate of wear of drill bits when the deposit is drilled as part of drill and blast mining operations.&lt;/p&gt;&#xA;&lt;p&gt;Similarly quartz would be of no economic value. Like garnet it is abrasive and it will affect equipment wear issues.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Goethite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Goethite&lt;/a&gt; is an iron mineral, usually of minor importance. It this situation it will most likely be a waste mineral.&lt;/p&gt;&#xA;&lt;p&gt;Rossovskyite, columbite and tantalite are the minerals of interest.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.mindat.org/min-46437.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rossovskyite&lt;/a&gt; contains &lt;a href=&quot;https://en.wikipedia.org/wiki/Tantalum&quot; rel=&quot;nofollow noreferrer&quot;&gt;tantalum&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Niobium&quot; rel=&quot;nofollow noreferrer&quot;&gt;niobium&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Titanium&quot; rel=&quot;nofollow noreferrer&quot;&gt;titanium&lt;/a&gt;. There is no indication of how of each metal is present and how much can be recovered overall.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Columbite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Columbite&lt;/a&gt; contains niobium, see comments for rossovskyite.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Tantalite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tantalite&lt;/a&gt; contains tantalum, see comments for rossovskyite.&lt;/p&gt;&#xA;&lt;p&gt;These minerals form 83 percent of the minerals tabulated. Only 59 percent contain tantalum.&lt;/p&gt;&#xA;&lt;p&gt;One thing that is favorable is all the minerals are oxides, there is not a mix of oxides and sulfides which would complicate metallurgical plant design and recoveries.&lt;/p&gt;&#xA;&lt;p&gt;Having said that, one needs to know if such oxides can be recovered easily and inexpensively. Most nickel mines mine nickel sulfides, not oxides, partly because nickel sulfides are easier and cheaper to process than nickel oxides. Nickel sulfides can be extracted using &lt;a href=&quot;https://www.911metallurgist.com/blog/flotation&quot; rel=&quot;nofollow noreferrer&quot;&gt;flotation&lt;/a&gt;, whereas nickel oxides usually require &lt;a href=&quot;https://www.911metallurgist.com/blog/autoclave-circuit&quot; rel=&quot;nofollow noreferrer&quot;&gt;autoclaves&lt;/a&gt; which are essentially large pressure cookers that use acid or ammonia to treat the nickel oxides.&lt;/p&gt;&#xA;&lt;p&gt;All you have is a table of minerals and it looks promising but there is no way to assess the economic viability of such a &amp;quot;deposit&amp;quot;. What you need is a table which states the amount of metal that can be sold, stated as either so many tonnes of rock containing a particular percent of each metal of interest and the associated mining and metallurgical recoveries (i.e. something like, 200 Mt @ 2% Ta with a mining recovery of 95% and a metallurgical recovery of 85%) or so many tonnes of metal recovered (i.e. 3.5 Mt of Ta, accounting for mining and metallurgical recoveries).&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-09-23T01:31:31.733" LastActivityDate="2021-09-23T01:31:31.733" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22849" PostTypeId="1" CreationDate="2021-09-20T11:40:43.333" Score="1" ViewCount="73" Body="&lt;p&gt;I have a number of points in Europe I would like meteorological data for. More specifically, I am looking for data that is relevant in Air Quality models, like wind, temperature and humidity.&lt;/p&gt;&#xA;&lt;p&gt;The time frame I am looking for data is in the time interval 2015-2018. Preferably it's hourly data.&lt;/p&gt;&#xA;&lt;p&gt;Is there any API I can use that gives me the data I need given longitudes and latitudes as input?&lt;/p&gt;&#xA;" OwnerUserId="24467" LastActivityDate="2021-09-20T11:40:43.333" Title="Meteorological Data API with Python" Tags="|meteorology|software|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22850" PostTypeId="1" AcceptedAnswerId="22855" CreationDate="2021-09-20T13:54:14.303" Score="4" ViewCount="490" Body="&lt;p&gt;I have been looking at the CMIP6 model outputs for 'hur' (Relative Humidity/RH) and I see that they are not scaled to be between 1 and 100 (the units are percent).&lt;/p&gt;&#xA;&lt;p&gt;Why is this? Is it just an oversight and everyone knows that they need to set anything above 100 to 100, or is there a significant reason for not scaling the data? From reading other answers here, it could be due to supersaturation, but I get the impression that that shouldn't be particularly widespread..the example I am looking at from cmip6 for a January climatology has values &amp;gt;100 over large swathes of Russia, Greenland and Canada.&lt;/p&gt;&#xA;" OwnerUserId="24395" LastEditorUserId="2470" LastEditDate="2021-09-20T15:38:04.533" LastActivityDate="2021-09-21T15:45:18.180" Title="Why are the CMIP6 model outputs for Relative Humidity not scaled to between 1-100%?" Tags="|climate-change|climate-models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22851" PostTypeId="2" ParentId="22846" CreationDate="2021-09-20T15:44:34.590" Score="3" Body="&lt;p&gt;In all likelihood it has no commercial viability in Africa. The lack of infrastructure will be a very large barrier to any production. No comment on political instability. To illustrate: in about 1970 Amoco considered producing copper from vast well-defined ore bodies. (I remember pretty well because a friend got to go to Africa to verify core test results and I was envious). Amoco made detailed cost estimates.&lt;/p&gt;&#xA;&lt;p&gt;They needed:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;A few hundred miles of railroad&lt;/li&gt;&#xA;&lt;li&gt;A canal or very large pipe to bring in water many miles&lt;/li&gt;&#xA;&lt;li&gt;A power plant for electricity (likely fueled with imported oil)&lt;/li&gt;&#xA;&lt;li&gt;A town, schools, hospital, and stores for workers&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Then the facilities for refining and smelting the copper. The by-product cobalt would have doubled world supply, but you can never have too much cobalt. Amoco estimated it would cost a couple billion US dollars, 1970 dollars, before the first shovel of copper ore was lifted. They decided the risk was too high. The copper is still there, parts of the ore body contain 100 times more copper concentration than copper mined in the US today.  But the major corporations still considered it too great a risk.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastEditorUserId="6298" LastEditDate="2021-09-20T18:21:40.607" LastActivityDate="2021-09-20T18:21:40.607" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22853" PostTypeId="1" AcceptedAnswerId="22854" CreationDate="2021-09-21T04:40:03.320" Score="8" ViewCount="729" Body="&lt;p&gt;How are active lava flows similar to fluvial geomorphology? You can search youtube for these dramatic videos of lava flows, and they all seem to look very similar to streams or rivers. I know that the major difference is laminar flow vs the sometimes turbulent flow of water.&#xA;Is there any literature comparing stream models to lava flows?&lt;/p&gt;&#xA;" OwnerUserId="23131" LastEditorUserId="10735" LastEditDate="2021-09-21T06:27:20.850" LastActivityDate="2021-09-22T16:54:32.870" Title="Similarities and differences between lava flows and fluvial geomorphology (rivers)" Tags="|volcanology|geomorphology|fluid-dynamics|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22854" PostTypeId="2" ParentId="22853" CreationDate="2021-09-21T07:03:47.810" Score="9" Body="&lt;p&gt;The similarities pretty much end at the fact that both water and lava flow downhill seeking the lowest possible level. As even the most &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonatite&quot; rel=&quot;noreferrer&quot;&gt;fluid lavas&lt;/a&gt; flow somewhat slower than water because of their higher density and &lt;a href=&quot;https://en.wikipedia.org/wiki/Viscosity&quot; rel=&quot;noreferrer&quot;&gt;viscosity&lt;/a&gt;, their lower speed and in particular their viscosity makes them far less erosive of the terrain they flow over/through. In fact lava usually freezes to the surfaces it is in contact with so the channels that carry lava on the surface get narrower and shallower, their sides build up where the edges of the flow freeze and they slowly raise the ground they are flowing over rather than eroding it. Lava flows look more like &lt;a href=&quot;https://en.wikipedia.org/wiki/River_delta&quot; rel=&quot;noreferrer&quot;&gt;river deltas&lt;/a&gt; than &lt;a href=&quot;https://en.wikipedia.org/wiki/Drainage_basin&quot; rel=&quot;noreferrer&quot;&gt;drainage basins&lt;/a&gt; but the mechanisms of deposition are very different. The closer model might be that of &lt;a href=&quot;https://en.wikipedia.org/wiki/Debris_flow&quot; rel=&quot;noreferrer&quot;&gt;debris flows&lt;/a&gt; and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Alluvial_fan&quot; rel=&quot;noreferrer&quot;&gt;alluvial fans&lt;/a&gt; they create but instead of running out of slope and saturation and depositing it's load of material a lava flow runs out of &lt;strong&gt;heat&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;There may be points of comparison between fluvial processes in the middle reaches of a river system and lava tubes but the study of lava tubes is pretty patchy, they're not the most accessible places on Earth.&lt;/p&gt;&#xA;&lt;p&gt;I know of a lot of literature concerning &lt;em&gt;interactions&lt;/em&gt; between lava flows and fluvial systems but not comparative studies, maybe someone else can help with that .&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2021-09-21T07:03:47.810" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22855" PostTypeId="2" ParentId="22850" CreationDate="2021-09-21T15:45:18.180" Score="4" Body="&lt;p&gt;This was a feature of CMIP5 too and the CMIP6 data request paper mentions it:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;... while near-surface relative humidity values of 140 % can, in principle, be realistic at a point in space and time, many of the high values in the CMIP5 archive, which represented time and grid cell averages, are likely to be caused by processing errors. Hence the upper-limit is set at 100.001 % and categorized as &lt;code&gt;suggested&lt;/code&gt;, in contrast to the limit for sea ice extent that has a robust limit of 100.001 %&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;em&gt;Juckes et al (2020): The CMIP6 Data Request (DREQ, version 01.00.31), Geosci. Model Dev., 13, 201–224, &lt;a href=&quot;https://doi.org/10.5194/gmd-13-201-2020&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.5194/gmd-13-201-2020&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;So modeling centers were permitted to clip their data to 100.001 %, but presumably many of them chose not to.  That papers cites &lt;a href=&quot;https://doi.org/10.1002/2017JD026909&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ruosteenoja et al (2017)&lt;/a&gt; for the CMIP5 analysis, who suggest several reasons:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;in some models supersaturations originate from the core of the model algorithm&lt;/li&gt;&#xA;&lt;li&gt;in others they have been formed only in the stage of creating the surface air moisture fields&lt;/li&gt;&#xA;&lt;li&gt;in several models both factors play a role: some degree of supersaturation has developed within the dynamic calculations but the excessive relative humidities have further been amplified when building the surface air humidity fields&lt;/li&gt;&#xA;&lt;li&gt;isobaric level fields [do not] represent the actual intrinsic model data but have been interpolated from the values given at model hybrid levels&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;They also contacted the modeling groups, who gave a variety of answers that fall into three categories:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the definition of RH with respect to ice rather than liquid water&lt;/li&gt;&#xA;&lt;li&gt;contradictions in the determination of specific humidity and air temperature for the near-surface level&lt;/li&gt;&#xA;&lt;li&gt;nonlinearity of saturated specific humidity as a function of temperature&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;That paper is open access (I think) and worth a read for more details on all those points.  It's also worth pointing out that there are plenty of screwy features of CMIP data, which is inevitable given the volumes of data, complexity of post-processing chains and expense of running the models.  It gets better each round, but there will always be something odd in there.  The important thing is to do what you're doing and query anything that doesn't seem right, rather than taking it at face value.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2021-09-21T15:45:18.180" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22856" PostTypeId="1" CreationDate="2021-09-22T04:06:54.773" Score="3" ViewCount="78" Body="&lt;p&gt;The &lt;a href=&quot;https://www.americanscientist.org/article/sunshine-on-a-cloudy-day&quot; rel=&quot;nofollow noreferrer&quot;&gt;American Scientist article&lt;/a&gt; nicely explains that clouds sometimes increase the level of UV radiations received on the earth surface. However, all the papers they cite focused on UV-B radiations. Can clouds increase the level of UV-A radiations received on the earth surface? If so, by how much, and in which condition(s)?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;More details from the American Scientist article:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;According to Sabburg, &amp;quot;In our latest research [soon to appear in the Journal of Atmospheric Research], we use new equipment and refine our methodology, and the &lt;strong&gt;highest UVI [an index of skin reddening] enhancement we found was 25 percent&lt;/strong&gt;.&amp;quot; But those values are with respect to  expected clear-sky UV. Compared with the level of attenuation usually seen when clouds are present, such measurements can actually be 50 to 75 percent higher than predicted, says Sabburg.&lt;/li&gt;&#xA;&lt;li&gt;Just how common is cloud enhancement? The various studies have found that between &lt;strong&gt;1.4 and 8 percent of all measurements show cloud enhancement compared with clear-sky values, depending on geographic location, but as many as 25 percent of those made on partly cloudy days may show it. Most often the enhancement lasts for 10 minutes&lt;/strong&gt; or less—not a concern for the sun worshiper—but it has been known to persist for an hour.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="587" LastActivityDate="2021-09-23T07:26:42.290" Title="Can clouds increase the level of UV-A radiations received on the earth surface? If so, by how much, and in which condition(s)?" Tags="|clouds|sun|uv-light|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22859" PostTypeId="1" CreationDate="2021-09-22T12:09:34.117" Score="6" ViewCount="219" Body="&lt;p&gt;I've been watching twilights for some time, and noticed that each time there's a very clear sky, an orange-pinkish glow is visible at the solar azimuth when Sun is somewhere between 1° and 5.5° below horizon. This glow shifts upwards as the Sun elevates still remaining under the horizon, and moves backwards when the Sun descends deeper under the horizon.&lt;/p&gt;&#xA;&lt;p&gt;See for example the following timelapse animation of an approaching sunrise, made from photo sequence shot in Namibia by Georg Zotti from the Stellarium team. Exposure time gradually decreases to account for sky brightness.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.imgur.com/2S8WzSR.png&quot; alt=&quot;&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;Below is a chart that shows time dependence of a middle vertical line of pixels from the animation above:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4BWHH.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4BWHH.png&quot; alt=&quot;&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;At first I thought this glow was due to some kind of very uniform cloud cover, but then I noticed that cirrus clouds, if a few are present near the horizon, stop being directly lit when the Sun is about 4.5° below the horizon, &lt;em&gt;before&lt;/em&gt; the glow disappears, while the glow remains present until the Sun is somewhere about 5.5° below the horizon (these figures are from observations at 60°N,30°E). So I suppose the glow originates somewhere in the stratosphere, or at the very least several kilometers above the cirrus clouds.&lt;/p&gt;&#xA;&lt;p&gt;I've been able to find out that there exist stratospheric sulfur aerosols, but I don't know whether they are responsible for this: whether they are so homogeneous horizontally across hundreds of kilometers, whether they are dense enough to cause this glow etc..&lt;/p&gt;&#xA;&lt;p&gt;So, what exactly is the origin of this glow? What kind of particles, what size distribution and altitude profile do they have?&lt;/p&gt;&#xA;" OwnerUserId="12360" LastActivityDate="2021-09-22T12:09:34.117" Title="What exactly causes this moving orange glow before sunrise?" Tags="|atmosphere|atmospheric-radiation|upper-atmosphere|aerosol|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22860" PostTypeId="1" CreationDate="2021-09-22T14:26:38.257" Score="7" ViewCount="145" Body="&lt;p&gt;Firstly, since there are a lot of oxygen atoms at a height of 200km, and less energy is needed to produce a red aurora than a green aurora, so it should be easier to produce red auroras than green auroras and we should see more red auroras than green auroras, but we see more green aurora in reality. Why are red auroras rare? Is it true that red auroras need 200s for the 630 nm transition?&lt;/p&gt;&#xA;&lt;p&gt;Secondly, why do oxygen atoms (not oxygen molecules) cause auroras while molecular nitrogen cause auroras instead of atomic nitrogen?&lt;/p&gt;&#xA;" OwnerUserId="24494" LastEditorUserId="2470" LastEditDate="2021-09-22T16:39:20.773" LastActivityDate="2022-03-07T11:25:25.800" Title="Why are red auroras rare? Why do oxygen atoms (not oxygen molecules) cause auroras while molecular nitrogen cause auroras instead of atomic nitrogen?" Tags="|atmosphere|upper-atmosphere|auroras|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22861" PostTypeId="2" ParentId="22853" CreationDate="2021-09-22T16:54:32.870" Score="4" Body="&lt;p&gt;In terms of rheology, there is a key difference between water and lava: water is a Newtonian fluid, lava isn't. In early volcanology days, there has been attempts to model lava as a Newtonian fluid (&lt;a href=&quot;https://doi.org/10.1086/624778&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nichols, 1939&lt;/a&gt;). This approach may be a good approximation in some cases (very fluid lavas, like pāhoehoe flows), but does not work for more viscous lavas ('a'ā and block flows, see &lt;a href=&quot;https://doi.org/10.1007/s00445-016-1075-7&quot; rel=&quot;nofollow noreferrer&quot;&gt;Harris et al. (2017)&lt;/a&gt; for a review of these categories).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1111/j.1365-246X.1974.tb05460.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hulme (1974)&lt;/a&gt; was the first to model lava as a &lt;a href=&quot;https://en.wikipedia.org/wiki/Bingham_plastic&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bingham plastic&lt;/a&gt;. In Bingham rheology, the shear rate still scales linearly with shear stress (like in Newtonian rheology), but you need to reach a minimum amount of stress (the &amp;quot;yield stress&amp;quot;) before the flow starts. This rheology explains some key differences in terms of flow morphology, as stated by Hulme:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;If lava were an ideal Newtonian liquid it would flow downhill and would continue to flow even after the supply at the vent had ceased until it ponded in a depression. Furthermore the flow would spread laterally until it was restricted by topography or until surface tension prevented spreading by which time it would be extremely thin. Observations show that lava does not behave like this. Commonly it comes to rest on a slope as soon as the supply of fresh lava ceases and many flow fronts are high and steep although unconfined by topographic features. It is clear that there is some process which limits the flow of lava, brings it to rest on slopes and prevents its lateral spreading.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In recent years, progress has been made to model lava as a multi-phase fluid: lava is indeed a suspension of bubble and/or crystals in a silicate melt, and these particles play a role on lava rheology. Finally, there is the case of silica-rich flows (dacite and rhyolite flows), which have very high viscosities (&lt;span class=&quot;math-container&quot;&gt;$10^8-10^{12}$&lt;/span&gt; Pa s, compared to &lt;span class=&quot;math-container&quot;&gt;$10^3-10^6$&lt;/span&gt; Pa s for basalts). These flows are so viscous that they advance very slowly (typically 1-100 meters per day). Hence their flow dynamics are very different from that of water. Unless you consider &lt;em&gt;solid&lt;/em&gt; water: there are some similarities between these lava flows and the flow of glaciers, like the presence of ogives for instance (&lt;a href=&quot;https://doi.org/10.3189/S002214300002551X&quot; rel=&quot;nofollow noreferrer&quot;&gt;Thorarinsson, 1953&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Nichols (1939) Viscosity of Lava&lt;/p&gt;&#xA;&lt;p&gt;Thorarinsson (1953) Ogives in Lava Streams&lt;/p&gt;&#xA;&lt;p&gt;Hulme (1974) The Interpretation of Lava Flow Morphology&lt;/p&gt;&#xA;&lt;p&gt;Harris et al. (2017) Pāhoehoe, ‘a‘ā, and block lava: an illustrated history of the nomenclature&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2021-09-22T16:54:32.870" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22862" PostTypeId="2" ParentId="22856" CreationDate="2021-09-22T23:31:23.713" Score="2" Body="&lt;p&gt;I found one study from 2001 {1}:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;It  was  also  determined  that  for  a  fulltime  outdoor  worker,  &lt;strong&gt;the  additional  UVA  exposure  could  approach  approximately  that  of  one  third  of  a  full  winter’s  day&lt;/strong&gt;.  For  indoor  workers  with  an  outside  lunch  break  of  noon  to  1  pm,  the  additional  UVA  exposure  was  on  average  6.9  kJ m&lt;span class=&quot;math-container&quot;&gt;$^{-2}$&lt;/span&gt; over three cloud enhanced days. To the authors’ knowledge this is the &lt;strong&gt;first paper to present some evidence of cloud enhanced UVA human exposure&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The paper doesn't explain the mechanism causing the UV-A increase.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;{1} Sabburg, J. and Parisi, Alfio and Wong, J. C. F. (2001). Effect of cloud on UVA and exposure to humans. Photochemistry and Photobiology, 74 (3), 412-416. ISSN 0031-8655. [&lt;a href=&quot;https://scholar.google.com/scholar?hl=en&amp;amp;as_sdt=0%2C48&amp;amp;q=Sabburg%2C+J.+and+Parisi%2C+Alfio+and+Wong%2C+J.+C.+F.+%282001%29.+Effect+of+cloud+on+UVA+and+exposure+to+humans.+Photochemistry+and+Photobiology%2C+74+%283%29%2C+412-416.+ISSN+0031-8655.+A&amp;amp;btnG=&quot; rel=&quot;nofollow noreferrer&quot;&gt;GScholar&lt;/a&gt;] [&lt;a href=&quot;http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.563.2942&amp;amp;rep=rep1&amp;amp;type=pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;PDF&lt;/a&gt;]&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="587" LastEditorUserId="18081" LastEditDate="2021-09-23T07:26:42.290" LastActivityDate="2021-09-23T07:26:42.290" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22863" PostTypeId="1" CreationDate="2021-09-23T00:23:17.023" Score="5" ViewCount="42" Body="&lt;p&gt;We know that geochemical dispersion in stream sediment is much widespread, facilitating discovering mineral targets in a regional scale. However, we also know that there should be discrepancy in space between the geochemical anomalies in stream sediement and buried mineralization.&lt;/p&gt;&#xA;&lt;p&gt;I found there are a lot of published studies that used identified geochemical anomalies in stream sediment for mapping unknown mineralization directly, or as an evidence for mapping mineral prospectivity together with other geologic feature layers. They usually interpolated first the mineralization-related element concentrations with support of GIS, and used some algorithms for extract geochemical anomalies from the background. See, for example, &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0375674215300261.&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jpsU3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jpsU3.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The authors delineate the mineral targets based on the anomaly map (figure b).&lt;/p&gt;&#xA;&lt;p&gt;I am confused about why the geochemical anomalies in stream sediment can be used directly without considering the spatial discrepancy.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;The figures are from this paper:&#xA;&lt;a href=&quot;https://doi.org/10.1016/j.gexplo.2015.06.018&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/j.gexplo.2015.06.018&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11924" LastEditorUserId="11924" LastEditDate="2022-02-11T08:52:45.253" LastActivityDate="2022-02-11T08:52:45.253" Title="Can geochemical anomalies of stream sediment samples be used directly for mapping targets?" Tags="|geology|geochemistry|mineralogy|minerals|geospatial|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22864" PostTypeId="2" ParentId="12500" CreationDate="2021-09-23T03:15:27.353" Score="0" Body="&lt;p&gt;They might be looking at the problem backward.  It is now believed that new world monkeys are the descendants of old world monkeys that floated on mats of trees across a much narrower Atlantic tens of millions of years ago. Even then, the Atlantic was much wider than any gap in the Indonesian area. So Borneo is an exception in that it has a marsupial, the southern or short nosed brown bandicoot of southern Australia.  At the same tine, New Guinea has many placentals living alongside marsupials.  Perhaps only small animals are capable of spreading without a land bridge because their energy requirements won't let them survive long trips. Tortoises can survive months without eating and they occupy many islands worldwide.&lt;/p&gt;&#xA;" OwnerUserId="24497" LastActivityDate="2021-09-23T03:15:27.353" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22867" PostTypeId="2" ParentId="13280" CreationDate="2021-09-23T17:58:08.267" Score="1" Body="&lt;p&gt;I completely understand what your asking.  I too have observed the &amp;quot;difference&amp;quot; in the light of the day.  Morning light and afternoon light have a completely different look to them. I have no real way to prove this, but I believe this effect is due to the rotation of the Earth in relation to the Sun's position to the observer.&lt;/p&gt;&#xA;&lt;p&gt;What I mean is this. In the morning the rotation of the Earth is towards the Sun, increasing the frequency of the wavelengths of light we observe.  Shorter wavelengths tend toward the blue hues, and the light of the day appears blueish.  In the afternoon the rotation of the earth is away from the sun causing longer observed wavelengths or wavelengths that tend toward the reddish hues causing the light of the day to appear to be reddish.  During mid-day since the sun is directly overhead there is no distinction either way, and the light of the day appears bright and white.  This is just how I have justified this phenomenon.&lt;/p&gt;&#xA;" OwnerUserId="24505" LastEditorUserId="2470" LastEditDate="2021-09-23T18:57:16.430" LastActivityDate="2021-09-23T18:57:16.430" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22868" PostTypeId="2" ParentId="13280" CreationDate="2021-09-24T00:23:05.163" Score="1" Body="&lt;p&gt;This is an excerpt from a paper written on the subject... Why is sunset more reddish than sunrise? By Neerad Tanvi, Bikaner&lt;/p&gt;&#xA;&lt;p&gt;I never considered the settlement of dust at night, but that makes total sense.&#xA;...&#xA;The scattering is also related to the size and quantity of the scattering particles. During the night time the atmosphere is cool and the aerial particles and dust particles settle by morning whereas by evening they get dispersed. Thus, the scattering is more by evening than in the morning.&#xA;Lastly, since the earth is spinning from West to East, relatively we move towards the Sun during mornings (eastward) and away from the Sun during evenings (westward). There is one phenomenon, called, Doppler Effect, which adds to this differential.&#xA;In other words, there is an inherent natural cause for this difference between morning and evening sunlight.&#xA;Prof. A. Ramachandraiah&#xA;NIT, Warangal&lt;/p&gt;&#xA;" OwnerUserId="24506" LastActivityDate="2021-09-24T00:23:05.163" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22869" PostTypeId="1" AcceptedAnswerId="22870" CreationDate="2021-09-24T07:14:40.303" Score="6" ViewCount="268" Body="&lt;p&gt;For my research related to coastal Odisha, India I am mapping the coastal boundary. I have downloaded available Landsat images which date back to 1972. But I want to map the same for before 1972.&lt;/p&gt;&#xA;&lt;p&gt;I am interested in old topographic maps showing the coastal boundary of Odisha, preferably before 1970.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Does anyone know from where can I get the scanned map of the same?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="24507" LastEditorDisplayName="user20559" LastEditDate="2021-09-24T16:07:22.010" LastActivityDate="2021-09-24T16:07:22.010" Title="Old topographic maps of Odisha, India" Tags="|mapping|topography|cartography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22870" PostTypeId="2" ParentId="22869" CreationDate="2021-09-24T09:40:19.720" Score="7" Body="&lt;p&gt;The &lt;a href=&quot;https://maps.lib.utexas.edu/maps/index.html&quot; rel=&quot;noreferrer&quot;&gt;PCL Map Collection&lt;/a&gt; (University of Texas at Austin) is a huge online collection of maps. For India, they have &lt;a href=&quot;https://maps.lib.utexas.edu/maps/ams/india/&quot; rel=&quot;noreferrer&quot;&gt;a series from the U.S. Army Map Service&lt;/a&gt; which might be of interest, as it dates from the 50's and has a decent scale (1:250,000). They also have older maps from the British era, but the series doesn't seem to be complete. It might be worth looking for those at the Royal Geographical Society archives.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2021-09-24T09:40:19.720" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22873" PostTypeId="2" ParentId="22768" CreationDate="2021-09-24T10:32:46.253" Score="1" Body="&lt;p&gt;The back radiation looks to be calculated by summing all radiation components that the atmosphere (including clouds) absorbs and then subtracting the radiation it emits upwards. What remains is the radiation it emits downwards (i.e. back radiation). In the figure it is indeed:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ (67\ \mathrm{Wm^{-2}} + 24\ \mathrm{Wm^{-2}} + 78\ \mathrm{Wm^{-2}} + 350\ \mathrm{Wm^{-2}}) - (165\ \mathrm{Wm^{-2}} + 30\ \mathrm{Wm^{-2}}) = 324\ \mathrm{Wm^{-2}}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The &amp;quot;equivalent to 100 percent of the incoming solar energy&amp;quot; reference in NASA's website is a rough approximation and it is not a result of some conservation law that says the two amounts must be exactly equal. It only means &amp;quot;we have estimated that the atmosphere's back radiation is approximately equal to the incoming solar radiation&amp;quot; (and indeed &lt;span class=&quot;math-container&quot;&gt;$324\ \mathrm{Wm^{-2}}$&lt;/span&gt; is approximately 100 percent of &lt;span class=&quot;math-container&quot;&gt;$342\ \mathrm{Wm^{-2}}$&lt;/span&gt;). Other similar estimations are suggesting slightly different amounts and percentages, but all are more or less quite close to each other for each radiation component. See for example the respective figure in Chapter 2 of 2013 IPCC Report:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://www.ipcc.ch/site/assets/uploads/2018/02/Fig2-11-1-1024x673.jpg&quot; alt=&quot;IPCC 2013, The Physical Science Basis, Chapter 2, Figure 2.11&quot; /&gt;&lt;/p&gt;&#xA;" OwnerUserId="24481" LastEditorUserId="24481" LastEditDate="2021-09-25T08:58:32.680" LastActivityDate="2021-09-25T08:58:32.680" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22874" PostTypeId="1" CreationDate="2021-09-24T17:59:40.903" Score="6" ViewCount="166" Body="&lt;p&gt;This northern summer, 2021, there were wildfires in Southern Europe and floods in Germany nearly at same time, also, floods and wildfires in different parts of Turkey, and floods in Far East of Russia and wildfires in Siberia.&lt;/p&gt;&#xA;&lt;p&gt;Also, there was dry weather in the places where the wildfires were. So, it looks like that moisture was not transported to where it should be transported, by winds, and it rained where it should not normally have rained.&lt;/p&gt;&#xA;&lt;p&gt;I never saw anybody state that these things are connected this way, (except myself, I think I said this hypothesis 1-2 times). Probably, they do not say that because it is not known. In that case, I hope this question waits answers in future.&lt;/p&gt;&#xA;&lt;p&gt;Has anybody checked whether this idea is true?&lt;/p&gt;&#xA;&lt;p&gt;How can it be true?&lt;/p&gt;&#xA;" OwnerUserId="18752" LastEditorUserId="2470" LastEditDate="2021-09-24T20:54:01.577" LastActivityDate="2023-01-27T13:30:55.857" Title="Does global warming inhibit transport of moisture?" Tags="|meteorology|climate-change|wind|rainfall|" AnswerCount="5" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22877" PostTypeId="1" CreationDate="2021-09-25T04:31:13.147" Score="1" ViewCount="60" Body="&lt;p&gt;I recently found that each degree of warming increases water vapour by 7% and I've also learned that the atmosphere contains (on average) between 1-5% water vapour when saturated, this confused me a bit, and I wondered if this could affect the oxygen concentrations in big cities or maybe the effect is too small.&lt;/p&gt;&#xA;" OwnerUserId="22045" LastEditorUserId="2470" LastEditDate="2021-09-25T08:34:01.267" LastActivityDate="2021-09-25T08:44:39.693" Title="Does increased water vapour in atmosphere increase the risk of hypoxia?" Tags="|meteorology|climate-change|atmosphere|atmospheric-chemistry|climatology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22878" PostTypeId="2" ParentId="22874" CreationDate="2021-09-25T08:08:04.417" Score="5" Body="&lt;p&gt;Increased air temperature tends to increase the rate of moisture transfer, firstly because at a given &lt;a href=&quot;https://en.wikipedia.org/wiki/Humidity#Relative_humidity&quot; rel=&quot;noreferrer&quot;&gt;relative humidity&lt;/a&gt; and pressure warmer air has a higher &lt;a href=&quot;https://en.wikipedia.org/wiki/Humidity#Absolute_humidity&quot; rel=&quot;noreferrer&quot;&gt;absolute humidity&lt;/a&gt; and is carrying more water. Secondly warmer air causes more evaporation off the water and land.&lt;/p&gt;&#xA;&lt;p&gt;There are however a couple of issues that are becoming increasing apparent,&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Climate change is (through mechanisms we are yet to fully understand) increasing total rainfall in many areas while decreasing the &lt;em&gt;number of rainfall events&lt;/em&gt; they experience. So now when it rains it pours and we see a lot of flooding in areas where the usual pattern was for a lot of lighter rain throughout the year. Between those floods events we see much drier conditions, to the point of drought and forest fires where they had not previously been common.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;There has also been an increase in wet season rainfall in a number of &lt;a href=&quot;https://en.wikipedia.org/wiki/Fire_ecology&quot; rel=&quot;noreferrer&quot;&gt;fire dependent ecosystems&lt;/a&gt; making fuel more abundant during the traditional fire season which is becoming both longer and hotter.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2021-09-25T08:08:04.417" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22880" PostTypeId="2" ParentId="22877" CreationDate="2021-09-25T08:44:39.693" Score="2" Body="&lt;p&gt;The atmospheric concentration of oxygen is &lt;a href=&quot;https://en.wikipedia.org/wiki/Oxygen&quot; rel=&quot;nofollow noreferrer&quot;&gt;20.8 percent&lt;/a&gt;, which is a significantly large proportion of the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;Oxygen is being &lt;a href=&quot;https://www.oxygenlevels.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;depleted&lt;/a&gt; because of the &lt;a href=&quot;https://cdiac.ess-dive.lbl.gov/trends/oxygen/modern_records.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;burning of fossil fuels&lt;/a&gt;, but the rate of depletion is very small compared to the amount of oxygen present in the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;The burning of fossil fuels is more of problem for oxygen depletion than the amount of water vapor in the atmosphere. There is no risk of hypoxia due to increases in atmospheric water vapor. What risk there is is of increased humidity and temperature discomfort resulting from that.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-09-25T08:44:39.693" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22881" PostTypeId="2" ParentId="22874" CreationDate="2021-09-25T08:50:44.360" Score="0" Body="&lt;p&gt;If true, this would be an example of a &lt;a href=&quot;https://en.wikipedia.org/wiki/Teleconnection&quot; rel=&quot;nofollow noreferrer&quot;&gt;teleconnection&lt;/a&gt; affected by climate change. However the explanation of extreme drought and extreme precipitation, both as results of global warming, is generally considered to have the &amp;quot;opposite direction&amp;quot;: higher temperatures lead to increased evaporation rates and to clouds which store more water before they finally produce rainfall. Hence: on the one hand drought at certain locations, and on the other, larger amounts of water and thus increased precipitation over locations where it is expected to rain. That is, it is thought that global warming tends to intensify the water cycle, not dampen it.&lt;/p&gt;&#xA;&lt;p&gt;However, global warming also leads to stronger and more persistent heat waves at certain locations, which means that indeed storms are being &amp;quot;stuck&amp;quot; over other locations for longer times instead of spreading out over larger areas.&lt;/p&gt;&#xA;&lt;p&gt;Then, in order to answer whether a wildfire and a storm/flood are inter-related by one or (most likely) both of the above consequences of global warming, studying those concrete events and their causes is needed. This is probably already underway for the summer 2021 events.&lt;/p&gt;&#xA;" OwnerUserId="24481" LastEditorUserId="24481" LastEditDate="2021-09-25T12:57:06.983" LastActivityDate="2021-09-25T12:57:06.983" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22882" PostTypeId="1" CreationDate="2021-09-25T09:49:52.753" Score="6" ViewCount="368" Body="&lt;p&gt;For my project, I am looking for wave height information. My study area is the Odisha coast of the Bay of Bengal. What I have gathered from various research papers is that significant wave height is considered for the wave height. But I could not find any reliable source of the data.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Does anyone have any idea about where can I get the data?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="24507" LastActivityDate="2022-01-17T10:34:54.497" Title="Wave height data for Indian east coast" Tags="|oceanography|waves|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22883" PostTypeId="2" ParentId="22882" CreationDate="2021-09-25T10:24:51.070" Score="6" Body="&lt;p&gt;The paper &lt;em&gt;&lt;a href=&quot;https://www.ijemr.net/DOC/AssessingCoastalVulnerabilityToSeaLevelRiseBetweenGopalpurAndPuriOdishaCoastOfIndiaUsingRemoteSensingAndGIS(844-851).pdf&quot; rel=&quot;noreferrer&quot;&gt;Assessing Coastal Vulnerability to Sea-Level Rise between Gopalpur and Puri, Odisha Coast of India, using Remote Sensing and GIS&lt;/a&gt;&lt;/em&gt; on page 849 states it used wave height data from the &lt;a href=&quot;https://incois.gov.in/&quot; rel=&quot;noreferrer&quot;&gt;INCOIS website&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-09-25T10:24:51.070" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22884" PostTypeId="2" ParentId="22882" CreationDate="2021-09-25T14:07:12.377" Score="3" Body="&lt;p&gt;Usually, the most reliable wave data for any of these areas come from the Wavewatch III solutions. Either the global solution or the one for specific regions (there is an Indian Ocean solution). The data is available at the &lt;a href=&quot;https://polar.ncep.noaa.gov/waves/validation/gefsv12/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCEP site&lt;/a&gt; (&lt;a href=&quot;https://polar.ncep.noaa.gov/waves/validation/gefsv12/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://polar.ncep.noaa.gov/waves/validation/gefsv12/&lt;/a&gt;). In terms of what the right metric is for wave height, &lt;a href=&quot;https://en.wikipedia.org/wiki/Significant_wave_height&quot; rel=&quot;nofollow noreferrer&quot;&gt;significant wave height&lt;/a&gt; (the average wave height of the top &lt;span class=&quot;math-container&quot;&gt;$\frac{1}{3}$&lt;/span&gt; of the waves during a specific sample time) is the standard metric used in almost all applications related to wave dynamics.&lt;/p&gt;&#xA;&lt;p&gt;If you are interested in climatological data from the area, I think your best chance is the paper by &lt;a href=&quot;https://doi.org/10.1175/JTECH-D-14-00212.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Anoop et al. (2015)&lt;/a&gt;. It describes average wave height fields, but also the tendency over the last few years. Directly from their paper:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/t84uN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/t84uN.jpg&quot; alt=&quot;Average swell and sea wave heights&quot; /&gt;&lt;/a&gt;&#xA;(left) Mean swell and (right) wind sea height in the NIO by wave energy statistical method: (a) annual, (b) premonsoon [February–May (FMAM)], (c) monsoon [June–September (JJAS)], and (d) postmonsoon [October–January (ONDJ)]. All values are in meters.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="2470" LastEditDate="2021-09-25T16:00:00.077" LastActivityDate="2021-09-25T16:00:00.077" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22885" PostTypeId="1" CreationDate="2021-09-25T20:20:04.840" Score="4" ViewCount="37" Body="&lt;p&gt;I am attempting to create a very simple hydraulic erosion simulation against a heightmap.&lt;/p&gt;&#xA;&lt;p&gt;I am using Manning's equation to calculate velocity and discharge.  I have taken samples of Hjulstrom's diagram to represent critical limits for eroding or depositing material from the stream bed--for now assuming a uniform particle size, but I plan to add 4 different sizes later.  I am using information from various sources to select a relative best fit for Manning's Roughness Coefficient in different situations.&lt;/p&gt;&#xA;&lt;p&gt;What I have not been able to find are formulas for the following:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Stream capacity for a particle size&lt;/li&gt;&#xA;&lt;li&gt;Rate or quantity to erode for a particle size&lt;/li&gt;&#xA;&lt;li&gt;Rate or quantity to deposit for a particle size&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Plenty of material has alluded to increases in velocity or discharge effectively squaring or cubing an output, for example, but I have not seen anything like a formula except to find the critical limits themselves.&lt;/p&gt;&#xA;&lt;p&gt;Can anyone either provide some basic formulas for the above, or point me to some material that can help me estimate?  Perfect accuracy is not required, so even a very rough approximation would do.&lt;/p&gt;&#xA;" OwnerUserId="24523" LastActivityDate="2021-09-26T08:43:20.427" Title="How can I estimate capacity, erosion rate, and deposit rate of a stream?" Tags="|erosion|simulation|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22887" PostTypeId="2" ParentId="22874" CreationDate="2021-09-26T08:50:22.003" Score="0" Body="&lt;p&gt;No, in fact moisture rates increase. Because more warmth means more oceanic evaporation. Increasing humidity. Even local climates that are tyipcally dry accumulate more moisture. Africa during the Holocene had lakes the Size of US states, the Sahara was an alluvial plain with grasses and wetlands.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/KZcow.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KZcow.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;research on Australia Holocene wetness data.&#xA;&lt;a href=&quot;https://australian.museum/learn/australia-over-time/evolving-landscape/the-holocene-epoch/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://australian.museum/learn/australia-over-time/evolving-landscape/the-holocene-epoch/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-09-26T08:50:22.003" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22888" PostTypeId="1" CreationDate="2021-09-26T10:07:02.880" Score="4" ViewCount="224" Body="&lt;p&gt;I have some doubts regarding the &lt;a href=&quot;http://www.fao.org/soils-portal/data-hub/soil-maps-and-databases/faounesco-soil-map-of-the-world/en/&quot; rel=&quot;nofollow noreferrer&quot;&gt;FAO/UNESCO Soil Map of the World&lt;/a&gt;. I have downloaded the ESRI shapefile format of Digital Soil Map of the World (&lt;a href=&quot;https://storage.googleapis.com/fao-maps-catalog-data/uuid/446ed430-8383-11db-b9b2-000d939bc5d8/resources/DSMW.zip&quot; rel=&quot;nofollow noreferrer&quot;&gt;3rd download link&lt;/a&gt; on &lt;a href=&quot;https://data.apps.fao.org/map/catalog/srv/eng/catalog.search#/metadata/446ed430-8383-11db-b9b2-000d939bc5d8&quot; rel=&quot;nofollow noreferrer&quot;&gt;this page&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;Among other files, there are two MS excel sheets (&lt;code&gt;SU_Info.xls&lt;/code&gt; and &lt;code&gt;Generalized_SU_Info.xls&lt;/code&gt;) which provide the soil profile information like pH level, Organic Carbon contains, etc. as mentioned in the &lt;code&gt;SoilData.doc&lt;/code&gt; file.&lt;/p&gt;&#xA;&lt;p&gt;But I'm unable to understand the above-mentioned excel files.&lt;/p&gt;&#xA;&lt;p&gt;For example, the 2nd entry of &lt;code&gt;Generalized_SU_Info.xls&lt;/code&gt; is for the soil unit symbol &lt;code&gt;AF&lt;/code&gt;. &lt;code&gt;AF&lt;/code&gt; means &lt;code&gt;Ferric Acrisols&lt;/code&gt; (the name of the soil, from its symbol, can be found in the &lt;a href=&quot;https://storage.googleapis.com/fao-maps-catalog-data/uuid/446ed430-8383-11db-b9b2-000d939bc5d8/resources/SoilMap_hires.zip&quot; rel=&quot;nofollow noreferrer&quot;&gt;Digital Soil Map of the World - high-resolution map&lt;/a&gt;). But the subsequent entries in that excel sheets are &lt;code&gt;AF 1&lt;/code&gt;, &lt;code&gt;AF 2&lt;/code&gt;, and, &lt;code&gt;AF 3&lt;/code&gt;. These numbers don't correspond to any soil type.&#xA;I'm not able to understand the nomenclature of this file and am at loss in using the data like pH level, Organic Carbon content, etc.&lt;/p&gt;&#xA;&lt;p&gt;In other words, I'm not able to link the information of these excel sheets to the actual soil types.&lt;/p&gt;&#xA;&lt;p&gt;Can you explain to me the content of this file and how to link this information with the actual soil map?&lt;/p&gt;&#xA;&lt;p&gt;The information in this file can be very useful input to my research.&lt;/p&gt;&#xA;" OwnerUserId="24507" LastEditorUserId="20438" LastEditDate="2021-10-22T11:52:25.757" LastActivityDate="2021-10-22T11:52:25.757" Title="Generalized Soil Unit Information on Soil Characteristics of FAO/UNESCO Soil Map" Tags="|geology|soil|soil-science|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22889" PostTypeId="1" CreationDate="2021-09-26T16:47:47.630" Score="1" ViewCount="47" Body="&lt;h2&gt;Context&lt;/h2&gt;&#xA;&lt;p&gt;We have geothermal, engineering and construction clients who often need accurate estimates of ground temperatures for project sites before they have physical access to the sites (for feasibility studies, basic system design, etc.).&lt;/p&gt;&#xA;&lt;p&gt;We have built a hybrid Machine Learning and physics-based model, which we've made available to the public at &lt;strong&gt;&lt;a href=&quot;https://groundtemperatures.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;groundtemperatures.com&lt;/a&gt;&lt;/strong&gt;, to provide these estimates for our clients.&lt;/p&gt;&#xA;&lt;h2&gt;Question&lt;/h2&gt;&#xA;&lt;p&gt;I am just wondering if any of you have found other methods for estimating ground temperatures for locations that you do not have physical access to and for which there are no nearby geo-tech/borehole studies?&lt;/p&gt;&#xA;&lt;p&gt;Our model is generally &lt;strong&gt;accurate to 0.5 degrees Celcius&lt;/strong&gt; globally, from depths between 0.4m and 200 meters, when compared to real-world ground temperature measurements. So obviously we would be looking for something more accurate than that, which can handle similar depth ranges and also accounts for the time of year (seasonal variability), which our model also does.&lt;/p&gt;&#xA;" OwnerUserId="24526" LastActivityDate="2021-09-26T16:47:47.630" Title="Is there a more accurate method for estimating ground or soil temperatures" Tags="|temperature|models|soil|geothermal-heat|bedrock|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22891" PostTypeId="1" CreationDate="2021-09-27T03:13:38.977" Score="1" ViewCount="109" Body="&lt;p&gt;Gabbro is an intrusive, mafic, and igneous rock. How would it turn into sedimentary rock?&lt;/p&gt;&#xA;" OwnerUserId="24527" LastEditorDisplayName="user20559" LastEditDate="2021-09-28T08:20:34.403" LastActivityDate="2021-09-28T08:20:34.403" Title="What is the sedimentary form of gabbro/diabase? What would it look like?" Tags="|rocks|sedimentology|petrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22892" PostTypeId="2" ParentId="22891" CreationDate="2021-09-27T03:50:33.080" Score="1" Body="&lt;p&gt;The only way for any igneous rock to transform into sedimentary form is through erosion, grain by grain. It won't be done en masse. The most easily erodible parts will dislodge from the surface first.&lt;/p&gt;&#xA;&lt;p&gt;When the grains have deposited into a sedimentary bed, over time, they will just be grains of minerals. If there are other forms of igneous rock nearby and they erode into the same bed, over the same period, no-one will be able to distinguish a gabbro portion from another host rock portion.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-09-27T03:50:33.080" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22893" PostTypeId="1" CreationDate="2021-09-27T04:38:29.340" Score="11" ViewCount="248" Body="&lt;p&gt;&lt;strong&gt;Background&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I am trying to estimate wind speeds at a proposed wind farm site using the method described in this paper: &lt;a href=&quot;https://www.mdpi.com/1996-1073/14/9/2573/htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Modeling of Ethiopian Wind Power Production Using ERA5 Reanalysis Data&lt;/a&gt;. The approach is summarized in figure 2 of the paper.&lt;/p&gt;&#xA;&lt;p&gt;Short Summary, you get ERA5 reanalysis data, then you scale it relative to wind speed figures calculated in a microscale model (Global Wind Atlas) using a bunch of formulas.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;What I've done&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;I have downloaded 12 months of historic hourly ERA5 reanalysis data.&lt;/li&gt;&#xA;&lt;li&gt;I've taken hourly 100m wind speed readings from the 4 neighboring grid points near my site&lt;/li&gt;&#xA;&lt;li&gt;I've used bilinear interpolation to estimate wind speed at site.&lt;/li&gt;&#xA;&lt;li&gt;I've used wind_stats (&lt;a href=&quot;https://wind-stats.readthedocs.io/en/latest/getting-started.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;hyperlink here&lt;/a&gt; to get the site specific Generalized Wind Climate (gwc) file from the Global Wind Atlas. to use for statistical downscaling purposes.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;But this is where I get stuck&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;What I've having trouble with&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I am having two issues with the gwc file that I am unsure on how to resolve.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The gwc file provides the Weibull A &amp;amp; K parameters at a sector level (i.e. in 30 degree increments up to 360 degree, sort of in a wind rose format). Do I aggregate the sector figures up (if so, how?) or do I do I transform my ERA5 data into sectors then apply the downscaling formulas at that level?&lt;/li&gt;&#xA;&lt;li&gt;The gwc file doesn't give me a site specific roughness figure, instead it gives me 5 different values. how do I know which roughness figure to use? Do I need a different source of data to first determine what site roughness is?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;&lt;strong&gt;Help Requested&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Does anyone have any experience with the gwc file format? Any assistance be greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="18376" LastEditorUserId="18088" LastEditDate="2022-11-06T17:49:18.297" LastActivityDate="2022-11-06T17:49:18.297" Title="How to statistically downscale wind speeds?" Tags="|meteorology|weather-forecasting|wind|mesoscale-meteorology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22894" PostTypeId="2" ParentId="22502" CreationDate="2021-09-27T05:26:52.010" Score="3" Body="&lt;p&gt;Have you checked out &lt;a href=&quot;https://globalwindatlas.info/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Wind Atlas&lt;/a&gt;. It uses ERA5 reanalysis data then plugs it into meso and microscale models to get it down to a 250x250m grid.&lt;/p&gt;&#xA;" OwnerUserId="18376" LastActivityDate="2021-09-27T05:26:52.010" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22896" PostTypeId="2" ParentId="14369" CreationDate="2021-09-27T13:21:44.517" Score="2" Body="&lt;p&gt;Models are set up with a calendar (length of year), and run using that calendar - there is, usually, no interpolation to any other calendar afterwards.&lt;/p&gt;&#xA;&lt;p&gt;Yes, seasonal cycles in the forcing are adjusted to the relevant calendar - say 360 days.&lt;/p&gt;&#xA;" OwnerUserId="24529" LastActivityDate="2021-09-27T13:21:44.517" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22897" PostTypeId="1" AcceptedAnswerId="22905" CreationDate="2021-09-27T18:43:36.760" Score="6" ViewCount="135" Body="&lt;p&gt;Are there any studies that discuss what meteorological data I should look at if I am creating an air quality model with machine learning? That is, what should I extract from NCEI or ERA5 first if I have limited storage capacity?&lt;/p&gt;&#xA;&lt;p&gt;Something like wind speed is very obvious, but what else should I be looking for?&lt;/p&gt;&#xA;" OwnerUserId="24467" LastEditorUserId="543" LastEditDate="2021-10-06T06:08:42.593" LastActivityDate="2021-10-06T06:08:42.593" Title="What meteorological data is needed for air quality machine learning models?" Tags="|air-pollution|open-data|air-quality|machine-learning|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22898" PostTypeId="2" ParentId="22897" CreationDate="2021-09-27T19:50:26.030" Score="3" Body="&lt;p&gt;From Seigneur C., Dennis R. (2011) (free access &lt;a href=&quot;https://cfpub.epa.gov/si/si_public_record_report.cfm?Lab=NERL&amp;amp;dirEntryId=216023&amp;amp;fed_org_id=770&amp;amp;SIType=PR&amp;amp;TIMSType=Book&amp;amp;showCriteria=0&amp;amp;address=nerl&amp;amp;view=citation&amp;amp;sortBy=pubDateYear&amp;amp;count=100&amp;amp;dateBeginPublishedPresented=&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, probably not in the final published form):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Inputs to air quality models include the emission rates of primary air&#xA;pollutants and precursors of secondary air pollutants, meteorology&#xA;(three-dimensional fields of  winds, turbulence, temperature,&#xA;pressure, boundary layer height, relative humidity, clouds and  solar&#xA;radiation), and boundary conditions (baseline or background conditions in the case of  source-specific models; see Figure 8.1).&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Seigneur C., Dennis R. (2011) Atmospheric Modeling. In: Hidy G., Brook J., Demerjian K., Molina L., Pennell W., Scheffe R. (eds) Technical Challenges of Multipollutant Air Quality Management. Springer, Dordrecht. &lt;a href=&quot;https://doi.org/10.1007/978-94-007-0304-9_9&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1007/978-94-007-0304-9_9&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I am not qualified on the subject in order to distinguish which of the above-mentioned meteorological parameters would be the most important, but it makes sense that parameters related to circulation and temperature would be key factors.&lt;/p&gt;&#xA;" OwnerUserId="24481" LastActivityDate="2021-09-27T19:50:26.030" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22902" PostTypeId="2" ParentId="13484" CreationDate="2021-09-28T08:35:43.413" Score="0" Body="&lt;p&gt;@BarocliniCplusplus's answer is correct.&#xA;To convert Ozone (kg/kg) to (ppbv) you only need molar masses of dry air (28.9644 g/mol) and molar mass of Ozone (47.998 g/mol).&lt;/p&gt;&#xA;&lt;p&gt;(Mass mixing ratio in ppb) = (28.9644 / 47.9982) * 1e9 * (Mass mixing ratio in kg/kg)&lt;/p&gt;&#xA;&lt;p&gt;[Source: ECMWF webpage]&#xA;[1]: &lt;a href=&quot;https://confluence.ecmwf.int/pages/viewpage.action?pageId=153391710&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://confluence.ecmwf.int/pages/viewpage.action?pageId=153391710&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="19152" LastActivityDate="2021-09-28T08:35:43.413" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22904" PostTypeId="1" CreationDate="2021-09-28T14:40:26.553" Score="1" ViewCount="113" Body="&lt;p&gt;A bunch of climate scientists claim that &lt;a href=&quot;http://arctic-news.blogspot.com/p/extinction.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;humans will go extinct by 2026&lt;/a&gt;, when humanity crosses the major tipping point known as &amp;quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Arctic_sea_ice_decline#Implications&quot; rel=&quot;nofollow noreferrer&quot;&gt;Arctic Blue Ocean Event (BOE)&lt;/a&gt;&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;According to the climate scientists at &lt;a href=&quot;https://arctic-news.blogspot.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;Arctic News blog&lt;/a&gt;; due to &lt;a href=&quot;https://glennfay.medium.com/the-blue-ocean-event-will-be-a-tipping-point-for-our-climate-42c05898862c&quot; rel=&quot;nofollow noreferrer&quot;&gt;BOE&lt;/a&gt; several positive feedback loop will kick in. One of the major positive feedback loop would be large amount of methane released from &lt;a href=&quot;https://en.wikipedia.org/wiki/Arctic_methane_emissions&quot; rel=&quot;nofollow noreferrer&quot;&gt;Siberian permafrost&lt;/a&gt;. (Please refer: -  &lt;a href=&quot;https://en.wikipedia.org/wiki/Clathrate_gun_hypothesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;Clathrate gun hypothesis&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;Since I am not a climate scientist, I would like to ask the experts in the field of climatology, whether such reports are accurate or not. According to the aforementioned blog the global average temperature will rise up by 18 degree Celsius!&lt;/p&gt;&#xA;&lt;p&gt;Is it too late to stop climate change? Are there any solution to prevent Arctic ice from melting completely?&lt;/p&gt;&#xA;" OwnerUserId="24540" LastActivityDate="2021-09-30T05:44:35.280" Title="How serious is the issue of vast quantities of methane release from an ice-free Arctic?" Tags="|climate-change|greenhouse-gases|sea-ice|methane|arctic|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22905" PostTypeId="2" ParentId="22897" CreationDate="2021-09-28T15:35:12.517" Score="3" Body="&lt;p&gt;The variables needed for machine learning are different than a standard air quality model. It's actually a much shorter list because you don't have to numerically model atmospheric motion/chemistry/deposition.&lt;/p&gt;&#xA;&lt;p&gt;Most AQMs have a spatial domain that has horizontal and vertical depth.  However, the machine learning forecasts I've seen are only for point locations where meteorological and air quality variables are measured. That is to say, the machine learning model is trained using variables from a ground station, and is only valid for that location.  You can train multiple locations using similar variables, but each station would have it's own set of data to train with.&lt;/p&gt;&#xA;&lt;p&gt;I've seen machine learning forecasts from Washington State University for &lt;a href=&quot;http://lar.wsu.edu/tricitiesozone_img/ML_model_description.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;ozone&lt;/a&gt; and &lt;a href=&quot;https://enviwa.ecology.wa.gov/Documents/SmokeForecast.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;PM2.5&lt;/a&gt;, and the list of important meteorological variables are basically the same.&lt;/p&gt;&#xA;&lt;p&gt;For ozone they say:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Hourly data for six meteorological variables (temperature and relative&#xA;humidity at 2m, wind components u &amp;amp; v, planetary boundary layer height, and sea level pressure) from 4km WRF archives, time information (month, weekday and hour), and the previous day’s observed moving 8-hour averaged O3 mixing ratios are used to train the RF classifier models.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;For more info you can see the &lt;a href=&quot;http://lar.wsu.edu/nw-airquest/docs/20200610_meeting/NWAQ_20200609_1400_KaiFan.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;latest presentation given&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2021-09-28T18:19:40.337" LastActivityDate="2021-09-28T18:19:40.337" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22906" PostTypeId="2" ParentId="22888" CreationDate="2021-09-28T17:53:28.997" Score="1" Body="&lt;p&gt;From the readme.doc file, it looks that  1, 2 and 3 following AF and the other soil symbols in the excel files you mention are about this:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Texture classes&lt;/strong&gt; reflect the relative proportions of clay (fraction&#xA;less than 0.002mm), silt (0.002 - 0.05mm) and sand (0.05 - 2mm) in the&#xA;soil. Three textural classes are recognized: coarse (1): sands, loamy&#xA;sands and sandy loams with less than 18 percent clay and more than 65&#xA;percent sand; medium (2): sandy loams, loams, sandy clay loams, silt&#xA;loams, silt, silty clay loams and clay loams with less than 35 percent&#xA;clay and less than 65 percent sand; the sand fraction may be as high&#xA;as 82 percent if a minimum of 18 percent clay is present; and fine&#xA;(3): clay, silty clays, sandy clays, clay loams, with more than 35&#xA;percent clay.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I noticed that different units (AF, AG, etc.) all have only 1, 2 and 3 as follow-up numbers. Furthermore types 1 (AF 1, AG 1, etc.) have large sand percentages while types 3 (AF 3, AG 3, etc.) have large clay percentages. This makes sense with respect to the above quoted description of the three texture classes. Probably someone with further knowledge on this field can help more.&lt;/p&gt;&#xA;" OwnerUserId="24481" LastActivityDate="2021-09-28T17:53:28.997" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22907" PostTypeId="1" CreationDate="2021-09-28T22:26:08.370" Score="1" ViewCount="53" Body="&lt;p&gt;And how does this differ from the gravitational potential along the geoid (which is equal).&lt;/p&gt;&#xA;" OwnerUserId="24542" LastActivityDate="2021-09-28T22:26:08.370" Title="Does the magnitude of gravity stay the same at all points along the geoid" Tags="|geodesy|" AnswerCount="0" CommentCount="1" ClosedDate="2021-10-03T14:14:42.003" ContentLicense="CC BY-SA 4.0" />
  <row Id="22908" PostTypeId="1" AcceptedAnswerId="22909" CreationDate="2021-09-29T06:44:22.030" Score="1" ViewCount="47" Body="&lt;p&gt;In a previous IGCSE examination paper&lt;span class=&quot;math-container&quot;&gt;$^1$&lt;/span&gt;, the following question was asked and answer provided:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;State one source of mineral particles in soil.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Marking Scheme:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Accept any &lt;em&gt;one&lt;/em&gt; of:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;rock;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;down wash;&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;What's &amp;quot;down wash&amp;quot; and how is it responsible for providing minerals to soil?&lt;/strong&gt; Googling the term lead me to an aerodynamics definition, which I doubt is the one referred to by the marking scheme.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$^1$&lt;/span&gt; &lt;em&gt;UCLES. Environmental Management, 0680/12, Paper 1. Cambridge International General Certificate of Secondary Education, February/March 2017.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="23287" LastEditorUserId="23287" LastEditDate="2021-09-29T06:54:19.910" LastActivityDate="2021-09-29T07:51:57.820" Title="&quot;Down wash&quot; as a source for mineral particles in the soil" Tags="|soil|minerals|terminology|soil-science|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22909" PostTypeId="2" ParentId="22908" CreationDate="2021-09-29T07:51:57.820" Score="2" Body="&lt;p&gt;Downwash can be part of some erosion environments where minerals are moved down from their host rock environment to another location.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://vro.agriculture.vic.gov.au/dpi/vro/portregn.nsf/pages/port_lf_sig_sites_black_snake&quot; rel=&quot;nofollow noreferrer&quot;&gt;Black Snake Range - Granite Slopes&lt;/a&gt;, Victoria, Australia&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The crest of the divide rises to almost 400 metres and at this site there are numerous exposed granite slopes and large boulders near the ridge crest. The lower slopes have a cover of granite downwash and the minor valleys have become partly infilled with this granitic sand wash, and hence they are swampy&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.southdowns.gov.uk/wp-content/uploads/2015/03/ILCA-2005-Appendix-K-Mixed-Farmland-and-Woodland-Vale.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Southdowns&lt;/a&gt;, UK, page 4&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Overlying the bedrock geology are drift deposits of alluvium (along the numerous&#xA;streams) and ‘head’ (downwash deposits at the base of the Greensand Hills around&#xA;Liss and Petersfield).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In the Discussion section of &lt;a href=&quot;https://www.hindawi.com/journals/jgr/2009/589037/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Slope Stability and Slope Formation in the Flysch Zone of the Vienna Forest (Austria)&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The downwash of the basal clays and marls, uncovering the solid bedrock, has to be regarded as the main aspect of this phase&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-09-29T07:51:57.820" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22910" PostTypeId="1" CreationDate="2021-09-29T08:50:50.947" Score="1" ViewCount="38" Body="&lt;p&gt;I am looking for a list that contains either the size of estuaries or river mouths of European rivers. Is there such a list available somewhere? I have been looking for a while but only found lists covering the river length or the amount of discharge.&lt;/p&gt;&#xA;" OwnerUserId="24544" LastEditorUserId="2470" LastEditDate="2021-09-29T09:21:12.973" LastActivityDate="2021-09-29T09:21:12.973" Title="List of estuary/mouth size for European rivers" Tags="|rivers|estuary|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22911" PostTypeId="1" AcceptedAnswerId="22935" CreationDate="2021-09-29T15:59:08.790" Score="4" ViewCount="237" Body="&lt;h2&gt;Context&lt;/h2&gt;&#xA;&lt;p&gt;The image below shows that one of the three particle movement patterns of radiation particles that are captured in the Van Allen belts is a longitudinal drift motion:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/xzeAk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xzeAk.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;However, I am experiencing some difficulties in understanding what causes this motion, and most sources I look into either simply state this motion exists, or go in detailed analysis on e.g. the magnitude of this motion without explaining what causes it.&lt;/p&gt;&#xA;&lt;h2&gt;Question&lt;/h2&gt;&#xA;&lt;p&gt;Hence I would like to ask: &lt;em&gt;What causes the westward drift of protons captured in the Van Allen Belts?&lt;/em&gt;&lt;/p&gt;&#xA;&lt;h2&gt;Hypothesis&lt;/h2&gt;&#xA;&lt;p&gt;I thought perhaps a Lorentz force w.r.t. the Interplanetary Magnetic Field (IMF) and (semi) circular (bouncing) motion around Earth may cause this drift, but I am experiencing some difficulties in confirming/rejecting this hypothesis.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/2e85X.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2e85X.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24546" LastActivityDate="2021-10-04T00:28:06.460" Title="Why do electrons drift Eastwards in the Van Allen belts?" Tags="|geomagnetism|electromagnetism|ionizing-radiation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22912" PostTypeId="1" CreationDate="2021-09-29T16:53:27.387" Score="4" ViewCount="59" Body="&lt;p&gt;In some parts of North America, such as California, the climax ecosystem has frequent forest fires -- that is, relatively dry forest that in absence of human intervention would burn perhaps every couple of years. This creates a more open landscape, with large trees widely spaced and little deadwood or underbrush.&lt;/p&gt;&#xA;&lt;p&gt;In other regions, such as the Carolinas, the climax ecosystem is for infrequent forest fires -- relatively moist forest that in absence of human intervention would burn perhaps on the order of once per century, during an unusually dry summer. This creates a forest with a lot of deadwood, moss, and so on, material that make fires very intense when they do happen.&lt;/p&gt;&#xA;&lt;p&gt;Where is the boundary between the two? The references I have found so far, remark in general terms that western states tend to have frequent forest fires and eastern states infrequent forest fires; can it be narrowed down more precisely than that? Is there a map available showing the extent of each, or even a list of which states would fall primarily into each category? Or does reasonably correspond to something for which maps are readily available, such as Köppen climate classification?&lt;/p&gt;&#xA;&lt;p&gt;In all cases, I'm interested in what the climates would produce in the absence of human intervention, i.e. the boundaries in temperature and rainfall conditions that would produce each kind of forest (or, in even drier conditions, no forest at all), not the changes in groundcover and fire frequency brought about by human activity.&lt;/p&gt;&#xA;" OwnerUserId="7911" LastEditorUserId="24481" LastEditDate="2021-10-03T12:22:15.430" LastActivityDate="2021-10-03T12:22:15.430" Title="Boundary between areas having frequent versus infrequent forest fires" Tags="|climate|geography|forest|wildfire|vegetation|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22913" PostTypeId="1" CreationDate="2021-09-29T17:14:31.900" Score="0" ViewCount="164" Body="&lt;p&gt;Where to find graphite rocks?&lt;/p&gt;&#xA;&lt;p&gt;I made researches in my city beach but I don't know where to find them.&lt;/p&gt;&#xA;" OwnerUserId="24547" LastEditorUserId="2470" LastEditDate="2021-09-30T07:43:59.173" LastActivityDate="2021-09-30T07:43:59.173" Title="Where to find graphite rocks?" Tags="|earth-history|rocks|" AnswerCount="1" CommentCount="3" ClosedDate="2021-10-03T21:30:10.073" ContentLicense="CC BY-SA 4.0" />
  <row Id="22914" PostTypeId="2" ParentId="22913" CreationDate="2021-09-29T20:14:08.860" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Graphite occurs naturally in metamorphic rocks or at the contact between an igneous intrusion and a carbonaceous body. Natural graphite deposits occur as lenses or layers of disseminated or massive flakes. What form the deposits take depends on the geologic background. One type called amorphous graphite, for example, is formed by the thermal metamorphism of coal.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.earthmagazine.org/article/mineral-resource-month-graphite-0/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.earthmagazine.org/article/mineral-resource-month-graphite-0/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2021-09-29T20:14:08.860" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22916" PostTypeId="2" ParentId="15705" CreationDate="2021-09-30T04:55:39.060" Score="-2" Body="&lt;p&gt;Metamorphic rocks occur when Rocks undergo geochemical changes whilst buried under layers of stratolith above.&#xA;Ex: Marble is a rock occurs when calcium and Carbonate rich rock (chalk, limestone, etc) gets geologically pressed and converted.&lt;/p&gt;&#xA;&lt;p&gt;Granite occurs naturally without such forces and can manifest fresh from volcanic eruption thou rare.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-09-30T04:55:39.060" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22919" PostTypeId="2" ParentId="21028" CreationDate="2021-09-30T06:49:09.470" Score="-2" Body="&lt;p&gt;ONE WAY to judge atmospheric CO2 of primitive prehistoric environments is to gauge geologic fossil plants by taxonomic type and geographic source (Taking into account continental drift) Finding tropical variant plant types in areas with now temperate/cold climate.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-09-30T06:49:09.470" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22920" PostTypeId="1" CreationDate="2021-09-30T07:22:58.463" Score="5" ViewCount="84" Body="&lt;p&gt;Last year I did an online summer course on remote sensing of volcanoes held by the University of Hawaii at Hilo. During the course, we had a presentation about the monitoring campaign during the &lt;a href=&quot;https://en.wikipedia.org/wiki/2018_lower_Puna_eruption&quot; rel=&quot;nofollow noreferrer&quot;&gt;2018 Kīlauea eruption&lt;/a&gt;. This eruption evolved from multiple fizzures that opened and resulted in a lava stream eventually ending into the sea, creating 875 acres (354ha) of new land. While presenting, the professor remarked that the lava flowing into the sea &amp;quot;created all kinds of steam and generated its own weather&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;I went to dig a little deeper and found a &lt;a href=&quot;https://rmets.onlinelibrary.wiley.com/doi/pdfdirect/10.1002/wea.3589?casa_token=ySKMrX7l380AAAAA:QMQKc09TTb8LLUDYnfcdeOJVhxSovQkJxBLyY-PaBbtdC03GudqnTAfv3WsLPWF_O5VTpKpD_A8_2j3Q&quot; rel=&quot;nofollow noreferrer&quot;&gt;detailed account of the weather situation during the eruption by the Royal Meteorological Society&lt;/a&gt;, and a story of possible volcanic-induced rain on &lt;a href=&quot;https://www.forbes.com/sites/marshallshepherd/2018/07/11/lava-from-the-mt-kilauea-volcano-may-be-creating-its-own-rainfall/?sh=1def2f702956&quot; rel=&quot;nofollow noreferrer&quot;&gt;Forbes&lt;/a&gt;. In this article, NOAA meteorologist James LaDue is quoted saying that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Here’s a lesser-known side effect of Kilauea’s latest eruptive tantrum - lava effect rain. Areas around the eruption saw nearly 10” of rain (on the date in question). The resulting rain partially crusted over the lava flows according to the U.S. Geological Survey. These rain cells weren’t any deeper than 15,000 ft deep but their persistence led to amazing totals. A previous lava effect rain event was much deeper, produced hundreds of lightning discharges, and numerous vortices (some possibly tornadoes).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;From what I have read, scientists still seemed to guess about the exact mechanisms behind it. Nevertheless, I was wondering if the contribution of steam resulting from the lava entering the sea would be able to produce such rainfall. Especially now with the current (September 2021) &lt;a href=&quot;https://www.euronews.com/2021/09/29/lava-from-la-palma-volcano-reaches-ocean-amid-toxic-gas-fears&quot; rel=&quot;nofollow noreferrer&quot;&gt;eruption of the Cumbre Vieja&lt;/a&gt; at the Canary Island La Palma leading to lava flowing into the sea as well.&lt;/p&gt;&#xA;&lt;p&gt;So: can steam resulting from lava entering the sea trigger rainfall? Or is volcanic-induced rainfall (if it exists) more influenced by local context, like the climate, latitude, or prevailing wind direction?&lt;/p&gt;&#xA;" OwnerUserId="21670" LastEditorUserId="21670" LastEditDate="2021-10-01T09:36:44.500" LastActivityDate="2021-10-01T09:36:44.500" Title="How common are volcanic-induced rain events?" Tags="|volcanology|rainfall|volcanic-eruption|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="22925" PostTypeId="1" CreationDate="2021-10-01T20:26:20.313" Score="3" ViewCount="1079" Body="&lt;p&gt;There are millions of square kilometers of below sea level dry land, mostly in desert areas. Reducing the mean temperature of the earth by 2 °C requires increasing cloud cover of stratus clouds by about 3% of the total area of the earth (assuming 80% reflection, typical of stratus), roughly 3.36 million square kilometers. I understand there are issues with how much evaporation would become cloud cover (and that cloud cover varies by type of cloud), nevertheless it seems that increased evaporation would increase cloud cover more or less in proportion to the distribution of clouds and most clouds are stratus, thus providing a cooling effect.&lt;/p&gt;&#xA;" OwnerUserId="24564" LastEditorUserId="6467" LastEditDate="2022-01-16T01:34:58.373" LastActivityDate="2022-01-16T01:34:58.373" Title="Why can't we increase cloud coverage of the Earth to reduce mean temperature by flooding basins to increase evaporation?" Tags="|climate-change|climate|greenhouse-gases|geoengineering|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22926" PostTypeId="2" ParentId="22925" CreationDate="2021-10-02T05:26:13.087" Score="9" Body="&lt;p&gt;Barring the technical feasibility of what you are proposing, there's a few points to consider which make your proposal problematic.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Water vapor is a greenhouse gas.  If you increase evaporation, you increase GHGs in the atmosphere.&lt;/li&gt;&#xA;&lt;li&gt;The albedo of water is very low, so if you increase surface area of water on Earth, you decrease the albedo&lt;/li&gt;&#xA;&lt;li&gt;Clouds are temporary, not a long-term solution to Earth's albedo.&lt;/li&gt;&#xA;&lt;li&gt;The best natural source of high albedo on Earth is snow/ice, not clouds.&lt;/li&gt;&#xA;&lt;li&gt;Unless you are using renewable energy sources, pumping large volumes of water continuously will require fuel usage, which will increase GHGs in the atmosphere.&lt;/li&gt;&#xA;&lt;li&gt;In order to address the issue of global temperature increase, we need to stop burning fuel as a globe and start sequestering carbon.  Efforts to increase albedo artificially are surely of little value while humans still emit 10 gigatons of CO&lt;sub&gt;2&lt;/sub&gt;e per year.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="543" LastEditorUserId="24481" LastEditDate="2021-10-02T16:36:16.523" LastActivityDate="2021-10-02T16:36:16.523" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22927" PostTypeId="2" ParentId="22925" CreationDate="2021-10-02T14:38:37.857" Score="3" Body="&lt;p&gt;Clouds form when moist air rises in a convection cell - cloud coverage area is largely controlled by the size of the convection cells, not moisture content.&lt;/p&gt;&#xA;&lt;p&gt;When temperature differences arise between different patches of the Earth, the air over the warmer part expands, creates low pressure, and pulls in moist air at the bottom as it rises. As the altitude increases the pressure drops and that reduces the temperature. When it gets high and cold enough the water falls out as rain. More moisture means heavier rain, starting at a lower altitude. But the size of the cloud is a function of the convection cell size, which depends on the pattern of temperature differences.&lt;/p&gt;&#xA;&lt;p&gt;To get more area covered by clouds, you would have to change the balance between warm areas and cold areas, so that the warmth was less intense and more geographically diffuse and the cold bits more intense and more geographically concentrated. The average temperature increasing or decreasing doesn't change the differences. Even the differences getting more or less intense doesn't change the sizes of the patches where it is higher or lower than the average. It's a third-order effect.&lt;/p&gt;&#xA;&lt;p&gt;Cloud physics is very complicated and not fully understood, and it's effect on the global energy balance likewise. Clouds form in warm areas, in the process cutting off the sunlight and cooling the land beneath them. They act a bit like a thermostat, smoothing out temperature variations - although not in the sense of aiming for a specific temperature. This results in feedback loops with various time delays - local warming causes more clouds causes local cooling causes reduced clouds. Their effect on the global energy balance depends on their altitude. Low clouds are made of warm water and radiate lots of infrared to space, high clouds are cold and radiate much less. They  have different effects during the day and the night - at night they cause less infrared to be radiated to space, being at a higher, cooler altitude, causing net warming. So what effect they have depends on what time of day they form. And there are feedback interactions with the temperature of the oceans which cause a massive time lag compared to the land which warms and cools very quickly, the effect of mountains and terrain and vegetation, different amounts of sunlight at different latitudes and seasons, and so on. The effect on the climate of clouds at the equator is very different to the effect of clouds in Antarctica during the long darkness of winter.&lt;/p&gt;&#xA;&lt;p&gt;Feedback cycles with time delays result in oscillations, and an oscillator forced by regular pushes from an independent driver (like summer/winter) tends to result in the phenomenon of 'chaos', as &lt;a href=&quot;https://eapsweb.mit.edu/sites/default/files/Index_Cycle_Alive_Well_85q.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;pioneered&lt;/a&gt; by the meteorologist Edward Lorenz. Even with perfectly understood deterministic rules, the behaviour can be irregular, complex, apparently 'random'; a fractal structure with variation on every time scale.&lt;/p&gt;&#xA;&lt;p&gt;In addition, the effect on global mean temperature is a cumulative process. If one supposed the net cloud cover over a year was a random number, centred on a fixed value but varying slightly from year to year, then the amount of heat in the system would be pushed up and down from the previous year's value by a random amount - a classic 'random walk'. If you plot a sequence of independent random numbers, you get a uniform fuzzy cloud of points. If you plot the cumulative sum of the same numbers, you get a rough line that wanders up and down like a mountain range. Over short periods, you get what appear to be rising and falling 'trends', just from random numbers. It's &lt;a href=&quot;https://esd.copernicus.org/articles/3/173/2012/esd-3-173-2012.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;very hard&lt;/a&gt; to distinguish this sort of thing from deterministic drivers; different researchers have come to radically different conclusions based on the same data. When the process driving it is not a nice, independent, mathematically well-behaved random number generator, but a chaotic process that can hop between different meta-stable states at long intervals, the issue is even worse. The natural background level varies by relatively large amounts over long time periods. Clouds add precisely this sort of noise to the climate.&lt;/p&gt;&#xA;&lt;p&gt;There isn't any global shortage of water surface to evaporate from - two thirds of the Earth's surface is water. And it's not generally any cloudier over the sea. Clouds are driven by &lt;em&gt;temperature differences&lt;/em&gt; causing air to rise or fall convectively. Clouds rising cool, and drop the excess moisture as rain. More moisture results in thicker cloud and more rain, but not necessarily a greater area covered. And the effects of cloud on climate are not so simple and straightforward, or easily understood.&lt;/p&gt;&#xA;&lt;p&gt;If you really want to reduce the albedo of the Earth, you'd be better off painting the ground white. Clouds are a highly unreliable way of doing it.&lt;/p&gt;&#xA;" OwnerUserId="24573" LastActivityDate="2021-10-02T14:38:37.857" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22928" PostTypeId="1" CreationDate="2021-10-02T22:42:31.623" Score="3" ViewCount="110" Body="&lt;p&gt;Not counting temporary events, like mass extinctions.&lt;/p&gt;&#xA;" OwnerUserId="24575" LastEditorUserId="24481" LastEditDate="2021-10-04T03:18:57.130" LastActivityDate="2021-10-04T14:24:02.550" Title="How far into the past would you have to go before you couldn't breathe the atmosphere?" Tags="|atmosphere|paleontology|biogeochemistry|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22929" PostTypeId="1" CreationDate="2021-10-03T04:50:50.947" Score="4" ViewCount="310" Body="&lt;p&gt;I have not been able to find any scholarly resources citing the impact of hydrocarbons in stasis underground.&lt;/p&gt;&#xA;&lt;p&gt;Hydrocarbons not being used for as a source of energy have very few noted needs for the environment.&lt;/p&gt;&#xA;&lt;p&gt;Do these “fossil fuels” underground help maintain homeostasis in microbial ecosystem  or aid in the growth of flora etc?&lt;/p&gt;&#xA;&lt;p&gt;Or are these substances: coal, animal remains and natural gas detrimental even if left untouched? Since most methods of break down are no longer an option due to decomposers not being able to reach these substances?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ucsusa.org/resources/environmental-impacts-natural-gas&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ucsusa.org/resources/environmental-impacts-natural-gas&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/scitable/knowledge/library/the-ecology-of-carrion-decomposition-84118259/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/scitable/knowledge/library/the-ecology-of-carrion-decomposition-84118259/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24577" LastEditorUserId="22648" LastEditDate="2021-10-04T16:53:38.910" LastActivityDate="2021-10-05T20:37:48.697" Title="What is the importance of hydrocarbons to the natural environment?" Tags="|environmental-protection|hydrocarbons|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22930" PostTypeId="2" ParentId="22928" CreationDate="2021-10-03T05:10:42.600" Score="3" Body="&lt;p&gt;Roughly 3,000,000,000 years ago Earth was a water world. This means terrestrial flora and fauna was 0%. Not much fun breathing in the atmosphere with limited photosynthesis from plants. And a nitrogen cycle that’s unrecognizable.&lt;/p&gt;&#xA;&lt;p&gt;To be fair anything before the Cambrian explosion would have been a harsh, most likely inhospitable environment.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.science.org/content/article/earth-s-ancient-atmosphere-was-half-thick-it-today-rev2&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.science.org/content/article/earth-s-ancient-atmosphere-was-half-thick-it-today-rev2&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nhm.ac.uk/discover/news/2018/february/plant-life-on-earth-is-much-older-than-we-thought.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nhm.ac.uk/discover/news/2018/february/plant-life-on-earth-is-much-older-than-we-thought.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nationalgeographic.org/media/age-earth/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nationalgeographic.org/media/age-earth/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24577" LastEditorUserId="24481" LastEditDate="2021-10-03T22:17:09.513" LastActivityDate="2021-10-03T22:17:09.513" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22931" PostTypeId="2" ParentId="22928" CreationDate="2021-10-03T13:46:37.347" Score="4" Body="&lt;p&gt;850 million years ago and earlier oxygen levels were below 6%, which is the  minimum for human survival. But at oxygen levels below 14% we start to be significantly impaired, and we have evolved with current levels of 20%. 14% was attained about 500 million years ago, but there have been significant low oxygen events since, notably at the start of the Jurassic 200 million years ago when levels were 60% of current concentrations.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastEditorUserId="21672" LastEditDate="2021-10-04T14:24:02.550" LastActivityDate="2021-10-04T14:24:02.550" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22932" PostTypeId="1" AcceptedAnswerId="22938" CreationDate="2021-10-03T14:48:06.833" Score="4" ViewCount="65" Body="&lt;p&gt;I've read that melanterite (FeSO&lt;sub&gt;4&lt;/sub&gt;*7H&lt;sub&gt;2&lt;/sub&gt;O) is colorless or white and gets to be green to blue with increase in Cu&lt;sup&gt;2+&lt;/sup&gt; impurities. But from my chemistry experience I know that iron sulfate is green when in solution and when hydrated. So why the mineral is white ? What is different here ?&lt;/p&gt;&#xA;" OwnerUserId="24578" LastEditorUserId="24578" LastEditDate="2021-10-04T08:49:13.340" LastActivityDate="2021-10-04T08:49:13.340" Title="Why is Melanterite white or colorless?" Tags="|mineralogy|minerals|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22933" PostTypeId="1" AcceptedAnswerId="22934" CreationDate="2021-10-03T17:49:33.227" Score="1" ViewCount="141" Body="&lt;p&gt;Which are the reasons to believe that the climate crisis can be solved within our type of civilisation, that is, without putting in jeopardy the important advances of humanity that have been achieved within the industrial era?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fMuF8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fMuF8.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6RGzx.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6RGzx.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Fossil fuel made it possible to feed more and more people and allowed higher and higher living standards to be achieved. It isn't realistic that billions of us will vote on parties that will decimate our standard of living. Has it been proved that this will not be necessary if fossil fuels are not to be used anymore?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://public.wmo.int/en/media/press-release/new-climate-predictions-increase-likelihood-of-temporarily-reaching-15-%C2%B0c-next-5&quot; rel=&quot;nofollow noreferrer&quot;&gt;According to the WMO&lt;/a&gt; there is a 40% chance of the annual average global temperature temporarily reaching 1.5°C above the pre-industrial level (the tipping point that has to be avoided according to the Paris Agreement) in at least one of the years 2021-25. This anthropogenic global warming is obviously a major threat, but how could the trend be broken without questioning basic advances that have been achieved in the modern epoch?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;Sources:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;The first figure shows the annual Keeling curve on a logarithmic scale (values minus 256).&lt;/p&gt;&#xA;&lt;p&gt;The second is taken from &lt;a href=&quot;https://industrialprogress.com/mcffdata/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://industrialprogress.com/mcffdata/&lt;/a&gt; fig 3:1 (including sources).&lt;/p&gt;&#xA;" OwnerUserId="16809" LastEditorUserId="24481" LastEditDate="2021-10-07T10:18:43.137" LastActivityDate="2021-10-07T10:18:43.137" Title="Is anthropogenic global warming unavoidable under modern civilisation?" Tags="|climate-change|co2|human-influence|fossil-fuel|predictability|" AnswerCount="1" CommentCount="6" ClosedDate="2021-10-04T05:36:26.907" ContentLicense="CC BY-SA 4.0" />
  <row Id="22934" PostTypeId="2" ParentId="22933" CreationDate="2021-10-03T21:47:13.780" Score="1" Body="&lt;p&gt;It is not an invariable and unavoidable correlation between economic growth and growth of CO2 emissions. Civilisation relying heavily on fossil fuels for energy will make CO2 levels rise as it grows but there are now other options for large scale energy production. Civilisation with zero emissions primary energy can grow without CO2 levels rising.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2021-10-03T21:47:13.780" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22935" PostTypeId="2" ParentId="22911" CreationDate="2021-10-04T00:28:06.460" Score="3" Body="&lt;p&gt;You are looking at &lt;span class=&quot;math-container&quot;&gt;$\nabla \vec B$&lt;/span&gt;-drift here (spoken: grad-E drift).&lt;/p&gt;&#xA;&lt;p&gt;This type of motion can be explained in a simplified way, when imagining a 2-D plane, separated at y=0 with two different magnetic field strengths, &lt;span class=&quot;math-container&quot;&gt;$B_z$&lt;/span&gt;. Let us say that for y&amp;gt;0, &lt;span class=&quot;math-container&quot;&gt;$\rm B_z$&lt;/span&gt; is large and for y&amp;lt;0, &lt;span class=&quot;math-container&quot;&gt;$\rm B_z$&lt;/span&gt; is weak. The strong field imparts a small gyro-radius for the charged particles, while the weak field imparts a large gyro-radius. Positive and negative charges orbit in opposite directions in the field, hence along the field gradients, they tend to drift left and right. This type of drift therefore can lead to net charge separation, which results in an E-field, which again leads to &lt;span class=&quot;math-container&quot;&gt;$\rm \vec E\times \vec B$&lt;/span&gt;-drift, which is uniform in direction for both charges.&lt;/p&gt;&#xA;&lt;p&gt;This is somewhat illustrated in &lt;a href=&quot;http://silas.psfc.mit.edu/introplasma/chap2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this lecture&lt;/a&gt;, part 2.3. There are other types of drift motions, but the aforementioned two are usually all covered in introductory lectures to plasma physics. Another good one is &lt;a href=&quot;http://farside.ph.utexas.edu/teaching/plasma/Plasmahtml/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2021-10-04T00:28:06.460" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22937" PostTypeId="1" CreationDate="2021-10-04T03:22:02.487" Score="1" ViewCount="53" Body="&lt;p&gt;Do these “fossil fuels” underground help maintain homeostasis in microbial ecosystem or aid in the growth of flora etc?&lt;/p&gt;&#xA;&lt;p&gt;Or are these substances: coal, animal remains and natural gas detrimental even if left untouched? Since most methods of break down are no longer an option due to decomposers not being able to reach these substances?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ucsusa.org/resources/environmental-impacts-natural-gas&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ucsusa.org/resources/environmental-impacts-natural-gas&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/scitable/knowledge/library/the-ecology-of-carrion-decomposition-84118259/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/scitable/knowledge/library/the-ecology-of-carrion-decomposition-84118259/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24577" LastActivityDate="2021-10-05T07:51:57.043" Title="Can Hydrocarbons be beneficial?" Tags="|geophysics|carbon-cycle|coal|oil-reserves|" AnswerCount="1" CommentCount="1" ClosedDate="2021-10-07T10:18:59.050" ContentLicense="CC BY-SA 4.0" />
  <row Id="22938" PostTypeId="2" ParentId="22932" CreationDate="2021-10-04T03:52:35.170" Score="3" Body="&lt;p&gt;You might be getting &lt;a href=&quot;https://en.wikipedia.org/wiki/Sulfite&quot; rel=&quot;nofollow noreferrer&quot;&gt;sulfite&lt;/a&gt;  (SO&lt;sub&gt;3&lt;/sub&gt;&lt;sup&gt;2−&lt;/sup&gt;) and &lt;a href=&quot;https://en.wikipedia.org/wiki/Sulfate&quot; rel=&quot;nofollow noreferrer&quot;&gt;sulfate&lt;/a&gt; (SO&lt;sub&gt;4&lt;/sub&gt;&lt;sup&gt;2−&lt;/sup&gt;) mixed up.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Iron(II)_sulfate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iron(II) sulfate&lt;/a&gt; is FeSO&lt;sub&gt;4&lt;/sub&gt;·xH&lt;sub&gt;2&lt;/sub&gt;O. As you state, &lt;a href=&quot;https://en.wikipedia.org/wiki/Melanterite&quot; rel=&quot;nofollow noreferrer&quot;&gt;melanterite&lt;/a&gt; is FeSO&lt;sub&gt;4&lt;/sub&gt;·7H&lt;sub&gt;2&lt;/sub&gt;O, which is a mineral form of hydrous iron(II) sulfate, an iron analogue of the copper sulfate chalcanthite.&lt;/p&gt;&#xA;&lt;p&gt;Various sources list the color of &lt;a href=&quot;https://www.mindat.org/min-2633.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;melanterite&lt;/a&gt; as being&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Colorless to white or green, also greenish-blue to blue with increased Cu content; colourless to pale green in transmitted light.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CWHj7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CWHj7.jpg&quot; alt=&quot;Melaterite_1&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://mineralexpert.org/article/melanterite-iron-sulfate-mineral-overview&quot; rel=&quot;nofollow noreferrer&quot;&gt;Another&lt;/a&gt; states (the emphasis is mine),&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Fresh melanterite is always green. It tends towards blue-green hues with higher Cu amount in the structure. And it turns pale green to almost white when dehydrated&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Melanterite is highly unstable material. It makes almost no sense to collect it as it requires very specific humidity and acidity. When removed from e.g. underground mines to the surface environment, it gets dehydrated and/or oxidized within hours or maximum few days.&lt;/p&gt;&#xA;&lt;p&gt;Melanterite is very easily dehydrated. It first turns into pale green color and then into white powdery material when almost completely dry. This is often mixture of various less hydrated iron sulfates like ferrohexahydrite (6x H&lt;sub&gt;2&lt;/sub&gt;O), siderotil (5x H&lt;sub&gt;2&lt;/sub&gt;O), rozenite (4x H&lt;sub&gt;2&lt;/sub&gt;O) and szomolnikite (1x H&lt;sub&gt;2&lt;/sub&gt;O).&lt;/p&gt;&#xA;&lt;p&gt;Divalent iron in melanterite is also very easily oxidized, which again results into decomposition of melanterite. There are various sulfates with varied amount of water and different ratio of Fe&lt;sup&gt;2+&lt;/sup&gt; and Fe&lt;sup&gt;3+&lt;/sup&gt; in the structure. These are further oxidized to pure Fe&lt;sup&gt;3+&lt;/sup&gt; sulfates and lastly converted to more stable Fe&lt;sup&gt;3+&lt;/sup&gt; minerals like goethite, lepidocrocite, or jarosite – depending on acidity of the environment and presence of water/humidity.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0S2oF.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0S2oF.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-10-04T03:52:35.170" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22939" PostTypeId="2" ParentId="22937" CreationDate="2021-10-04T05:11:02.523" Score="2" Body="&lt;p&gt;Generally, hydrocarbon fossil fuels cannot be regarded as being beneficial to life on Earth. Even human usage cannot be considered beneficial overall. Energy can be derived from fossil fuels but there have been and there are consequences: carbon dioxide emissions, pollution, impoverishment of some people while others get wealthy.&lt;/p&gt;&#xA;&lt;p&gt;Gas, prominently methane, is effectively naturally pressure cooked &lt;a href=&quot;https://en.wikipedia.org/wiki/Petroleum_reservoir&quot; rel=&quot;nofollow noreferrer&quot;&gt;crude oil&lt;/a&gt;. Generally oil and gas deposits occur deep underground and have no beneficial influence to life on Earth's surface.&lt;/p&gt;&#xA;&lt;p&gt;Gas and oil can escape from nearly surface deposits. Such fugitive emissions of gas only add to the green house gas situation. Fugitive oil leaks can and does kill life. Larger animals can be covered by such and die as a result of starvation or an ability to go about its normal life. Similarly, for smaller life forms that get entrapped or covered in such oil.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Coal&quot; rel=&quot;nofollow noreferrer&quot;&gt;Coal&lt;/a&gt; results from the deep burial of plants that have accumulated in ancient (from millions of years ago) swamps or bogs. Due to the lack of oxygen within such deposits, carbon with the deposits can react with hydrogen to form methane, which can escape into the atmosphere adding to the green house gas situation.&lt;/p&gt;&#xA;&lt;p&gt;There are various grades of coal, from brown coal (lignite), which can be soft to black coal, such as anthracite, which is hard.&lt;/p&gt;&#xA;&lt;p&gt;No life forms depend of coal or other hydrocarbon fossil fuels for there existence.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-10-04T05:11:02.523" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22940" PostTypeId="1" CreationDate="2021-10-04T06:01:03.700" Score="1" ViewCount="715" Body="&lt;p&gt;I am attempting to implement FD in 2D with a staggered grid scheme as per (Virieux 1986). I am having difficulties going from the numerical analysis formulas to the code for this particular scheme. As I have not seen any concrete examples for staggered grid FD.&lt;/p&gt;&#xA;&lt;p&gt;I would love to see an example. If anyone could link a book, paper or a webpage, It would be immensly appreciated.&lt;/p&gt;&#xA;&lt;p&gt;Cheers,&lt;/p&gt;&#xA;" OwnerDisplayName="user24541" LastActivityDate="2023-12-18T10:18:44.527" Title="Staggered Grid finite difference implementation for modelling the elastic wave equation in 2D?" Tags="|wave-modeling|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22941" PostTypeId="1" CreationDate="2021-10-04T07:47:27.693" Score="2" ViewCount="68" Body="&lt;p&gt;A friend of mine asked our teacher but the class was over and in online mode, I can't ask my teacher until the next lecture. It sparked my curiosity, I know we use carbon dating for finding the age of organic material, snowball hypothesis is there and Theories of Oparin Haldane tell us about primitive atmospheric conditions. Is there anything I don't know about, it may be some method in geography? Just tell me the name of the method if you can't tell in detail, I'm stuck on it &amp;quot;Modeling early earth&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="24581" LastEditorUserId="2470" LastEditDate="2021-10-04T08:34:57.647" LastActivityDate="2021-10-19T19:52:29.497" Title="What methods/apparatus are used to model the early Earth? What do we know of their accuracy?" Tags="|geology|models|earth-history|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22942" PostTypeId="2" ParentId="22941" CreationDate="2021-10-04T09:07:43.550" Score="1" Body="&lt;p&gt;For dating old geological material, &lt;a href=&quot;https://www.amnh.org/learn-teach/curriculum-collections/earth-inside-and-out/zircon-chronology-dating-the-oldest-material-on-earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;zircon dating&lt;/a&gt; is sometimes used. Also see &lt;a href=&quot;https://en.wikipedia.org/wiki/Uranium%E2%80%93lead_dating&quot; rel=&quot;nofollow noreferrer&quot;&gt;Uranium-lead dating&lt;/a&gt;. There is also data from Antarctic and Greenland &lt;a href=&quot;https://earthobservatory.nasa.gov/features/Paleoclimatology_IceCores&quot; rel=&quot;nofollow noreferrer&quot;&gt;ice cores&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Other things you could look are &lt;a href=&quot;https://www.physics.mcgill.ca/%7Ehilke/181/pictures/AnswerQEarth.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth formation theories&lt;/a&gt; - the core accretion model &amp;amp; the disk instability model as well as &lt;a href=&quot;https://en.wikipedia.org/wiki/Plate_tectonics&quot; rel=&quot;nofollow noreferrer&quot;&gt;plate tectonics&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Continental_drift&quot; rel=&quot;nofollow noreferrer&quot;&gt;continental drift&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;There are also the &lt;a href=&quot;https://en.wikipedia.org/wiki/Origin_of_water_on_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;theories about the origin of water on Earth&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-10-04T09:16:18.653" LastActivityDate="2021-10-04T09:16:18.653" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22943" PostTypeId="1" CreationDate="2021-10-04T15:31:39.887" Score="1" ViewCount="44" Body="&lt;p&gt;I got this formula for calculating-&lt;/p&gt;&#xA;&lt;p&gt;100x(EXP.((17.625x32)/(243.04+32)/EXP.((17.625x54)/(243.04+54)))=?&lt;/p&gt;&#xA;&lt;p&gt;The answer should be 43, but I Keep getting 65. Please, can anyone calculate this correctly?&lt;/p&gt;&#xA;&lt;p&gt;Thank You!&lt;/p&gt;&#xA;" OwnerUserId="24583" LastEditorUserId="24583" LastEditDate="2021-10-04T16:02:03.677" LastActivityDate="2021-10-04T16:02:03.677" Title="How to calculate relative humidity with temperature and dew point?" Tags="|geography|mathematics|" AnswerCount="0" CommentCount="13" ClosedDate="2021-10-07T01:43:40.783" ContentLicense="CC BY-SA 4.0" />
  <row Id="22944" PostTypeId="1" CreationDate="2021-10-05T03:04:40.820" Score="3" ViewCount="234" Body="&lt;p&gt;In the normal course of events, when continents move toward each other, at least one coast will be associated with a subduction zone and corresponding volcanic activity. When the Indian subcontinent was moving toward Asia, we would expect such to occur, as confirmed by the answer to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13558/volcanoes-in-the-alps-and-himalayas-and-the-subduction-of-tethys-sea&quot;&gt;Volcanoes in the Alps and Himalayas and the subduction of Tethys Sea&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The above also observes that there is no trace of such volcanic activity nowadays; it has been thoroughly buried and erased, which is understandable.&lt;/p&gt;&#xA;&lt;p&gt;At what point did volcanic activity cease? Would it have been around the time the sea between the two continents disappeared? Or would it have continued for some time after that, resulting in a landlocked but still highly volcanic mountain range?&lt;/p&gt;&#xA;" OwnerUserId="7911" LastActivityDate="2021-10-14T03:25:47.497" Title="When did the proto-Himalayas become non-volcanic?" Tags="|geology|plate-tectonics|volcanology|mountains|subduction|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22945" PostTypeId="2" ParentId="22944" CreationDate="2021-10-05T06:09:26.407" Score="5" Body="&lt;p&gt;We don't know for sure because A. the evidence has almost all been erased by the continued crustal shortening of the area where the volcanic arc(s) would have been. B. the region is huge and volcanism will have varied in duration greatly across the range as a whole. The &amp;quot;core range&amp;quot; of the Himalaya has lost on the order of 6000km (~2500 miles) of crust to subduction and subsequent orogeny. The current tops of many of the mountains of the Himalaya were once buried deeply enough to start metamorphosing and most datable volcanic deposits would have been on a surface that has long since been eroded away. There are basalt feeder dykes in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Abor_Formation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Abor formation&lt;/a&gt; that yield crystalisation dates as young as &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S1674987112000072&quot; rel=&quot;nofollow noreferrer&quot;&gt;25Ma&lt;/a&gt; so that puts a limit on that particular part of the range.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="10735" LastEditDate="2021-10-06T04:56:27.813" LastActivityDate="2021-10-06T04:56:27.813" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22946" PostTypeId="2" ParentId="22462" CreationDate="2021-10-05T07:42:58.873" Score="0" Body="&lt;p&gt;A flood is a temporary occurance when rate of water inundation exceeds rate of the landscapes capacity to dispose or absorb it.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-10-05T07:42:58.873" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22947" PostTypeId="2" ParentId="22929" CreationDate="2021-10-05T07:50:25.287" Score="2" Body="&lt;p&gt;Hydrocarbons exist as short chain molecules; that act as feedstock for biological consumption. As just geologically stored carbon, it's useless. Apart from methane and ethylene, hydrocarbons as a whole play no large biological role. As hydrocarbons. When humanity re-released this carbon into the Biosphere as &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; it drove stockpiles of available carbon for biology up. All photosynthetic organism... plants, bacteria, algae needs &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; in order to produce sugars that are the primary energy source for every plant and animal. To be fair, water is also essential, as are nitrogen, potassium, phosphorus, and many other minor elements. But &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; is the most important, as all life on earth is carbon-based, and the carbon comes from &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; in the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastEditorUserId="6129" LastEditDate="2021-10-05T20:37:48.697" LastActivityDate="2021-10-05T20:37:48.697" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22949" PostTypeId="1" AcceptedAnswerId="22952" CreationDate="2021-10-05T11:30:11.180" Score="3" ViewCount="142" Body="&lt;p&gt;I have downloaded a number of future simulations for a group of GCMs from CMIP6 for the variable Relative Humidity (hur).&#xA;I chose the 100000pa level to view the RH data in panoply for the EC-Earth iteration and it looked normal/as expected:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/wjvuP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wjvuP.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, when I checked the other models at (or near to) this Pa level, most of the RH data was missing from the landmasses:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/7CmbM.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7CmbM.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Am I using the wrong Pa level? Is this data just missing near the surface?&lt;/p&gt;&#xA;&lt;p&gt;Any advice appreciated.&lt;/p&gt;&#xA;" OwnerUserId="24395" LastActivityDate="2021-10-05T12:31:38.900" Title="What Pa level should I use when looking at Relative Humidity data from CMIP6 models?" Tags="|climate-models|humidity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22950" PostTypeId="2" ParentId="9738" CreationDate="2021-10-05T11:52:53.273" Score="1" Body="&lt;p&gt;As answered before, it depends on where are you from. In English-speaking countries Oceania usually includes Australia. In other countries, e.g. Russia or Poland, there is a distinction between &amp;quot;continent&amp;quot; and &amp;quot;part of the world&amp;quot;. The continent is Australia, however &amp;quot;part of the world&amp;quot; is &amp;quot;Australia and Oceania&amp;quot;. The same term, &amp;quot;Australia and Oceania&amp;quot; is used e.g. by National Geographic.&lt;/p&gt;&#xA;" OwnerUserId="24586" LastActivityDate="2021-10-05T11:52:53.273" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22952" PostTypeId="2" ParentId="22949" CreationDate="2021-10-05T12:31:38.900" Score="4" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;What Pa level should I use...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;That really depends what you're trying to do with it.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Is this data just missing near the surface?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The pressure level 1 &lt;code&gt;hur&lt;/code&gt; data in your ACCESS model plot are missing because the surface pressure in those grid boxes is less than 962.5 hPa lower bound of that layer.  In other words, that atmospheric layer doesn't exist above those grid boxes, so properties of it like temperature and humidity are not defined.  If you look at pressure levels 2, 3, etc, you should notice less and less of the area is undefined.&lt;/p&gt;&#xA;&lt;p&gt;To be honest, looking at pressure level 1 isn't very useful for this reason.  In some places it'll be undefined, in some places it'll be inside the boundary layer and in some places it'll be outside, making interpretation difficult.&lt;/p&gt;&#xA;&lt;p&gt;If you're looking at a single level this close to the surface, then you probably really want to look at the screen-level humidity variable, &lt;code&gt;hurs&lt;/code&gt;.  That will be defined everywhere, is more comparable between models and is usually more relevant when looking at surface level impacts and applications.  The same is true for temperature variables &lt;code&gt;ta&lt;/code&gt; and &lt;code&gt;tas&lt;/code&gt;.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2021-10-05T12:31:38.900" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22953" PostTypeId="1" AcceptedAnswerId="22954" CreationDate="2021-10-05T22:58:00.647" Score="2" ViewCount="92" Body="&lt;p&gt;Historically cyclones were very very rare along the southern coast of Iran, maybe one in a century. But in recent years two cyclones hit Iran and northern Oman: Cyclone Gonu in 2007 and recently cyclone Shaheen. The Persian Gulf water temperature is very high in the summer and the beginning of spring. Even a 36 centigrade degree water temperature was recorded off Kharg Island. So what happens if a cyclone can reach to such very warm water?&lt;/p&gt;&#xA;" OwnerUserId="24591" LastEditorUserId="2470" LastEditDate="2021-10-06T04:36:03.890" LastActivityDate="2021-10-06T04:36:03.890" Title="What happens if a cyclone can reach the warm waters of the Persian Gulf?" Tags="|climate-change|cyclone|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22954" PostTypeId="2" ParentId="22953" CreationDate="2021-10-06T02:14:02.443" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Sea surface temperatures warm dramatically as one moves toward the western Gulf of Oman and the Persian Gulf, where the water is protected from mixing and exposed to fierce subtropical summer sun. Despite this fuel for tropical cyclones, none has ever been recorded in the Persian Gulf, mainly because of persistent wind shear and dry air. However, the idea was explored in “Grey swan tropical cyclones”, a fascinating study by Ning Lin and Kerry Emanuel published in Nature Climate Change in 2015. By “seeding” the region’s observed climate of 1980-2010 with 3100 weak, randomly positioned tropical cyclones, then modeling those cyclones, the authors found that at least two grew to formidable strength in the Persian Gulf, including one stronger than any observed on Earth to date!&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://yaleclimateconnections.org/2021/10/shaheen-headed-for-historic-landfall-in-oman/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://yaleclimateconnections.org/2021/10/shaheen-headed-for-historic-landfall-in-oman/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2021-10-06T02:14:02.443" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22955" PostTypeId="2" ParentId="22940" CreationDate="2021-10-06T05:19:35.993" Score="3" Body="&lt;p&gt;Here is a simple MATLAB script for a simple FD implementation (2nd order accurate in space and time) for the acoustic wave equation, which is identical to Virieux (1986) under the assumption of &lt;span class=&quot;math-container&quot;&gt;$\mu=0$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\sigma_{xx}=\sigma_{zz}=-p$&lt;/span&gt; for pressure &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt;. Let me know if that helps or not, and maybe we can update the answer from there.&lt;/p&gt;&#xA;&lt;p&gt;The main confusion in staggered grid modeling is that you have multiple grids (here, e.g., pressure &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; and the horizontal and vertical particle velocities &lt;span class=&quot;math-container&quot;&gt;$v_x$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$v_z$&lt;/span&gt;), and the computer implementation only allows you to index them at full integers &lt;code&gt;p[1]&lt;/code&gt;, &lt;code&gt;p[2]&lt;/code&gt;, &lt;code&gt;vx[1]&lt;/code&gt;, ..., but in practice they may be offset, i.e., the location of &lt;code&gt;p[1]&lt;/code&gt; is not the same location as &lt;code&gt;vx[1]&lt;/code&gt;, they are actually offset by &lt;span class=&quot;math-container&quot;&gt;$\Delta x/2$&lt;/span&gt;, just indexed by the same integer.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ehjit.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ehjit.png&quot; alt=&quot;Copied from https://www.researchgate.net/figure/Spatially-staggered-finite-difference-grid-for-solution-of-acoustic-wave-propagation_fig1_235037633&quot; /&gt;&lt;/a&gt;&#xA;Figure copied from &lt;a href=&quot;https://www.researchgate.net/figure/Spatially-staggered-finite-difference-grid-for-solution-of-acoustic-wave-propagation_fig1_235037633&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/figure/Spatially-staggered-finite-difference-grid-for-solution-of-acoustic-wave-propagation_fig1_235037633&lt;/a&gt; . The code is my own.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;%% Setting up the spatial &amp;amp; temporal model&#xA;% --- The true dimensions (in meters)&#xA;lx = 1200;&#xA;ly = 1200;&#xA;&#xA;% --- The true total run-time (in seconds)&#xA;lt = 5;&#xA;&#xA;% --- The true medium parameters (m/s and kg/m3)&#xA;vp  = 2000;&#xA;rho = 1500;&#xA;&#xA;% --- The finite-difference parameters&#xA;dx = 2;&#xA;dy = dx;&#xA;dt = 0.5e-3;&#xA;&#xA;% --- The associated discrete grid in space and time&#xA;nx = floor(lx/dx);&#xA;ny = floor(ly/dy);&#xA;nt = floor(lt/dt);&#xA;x = [0:nx-1]*dx;&#xA;y = [0:ny-1]*dy;&#xA;t = [0:nt-1]*dt;&#xA;&#xA;% --- Source-time wavelet (supply central frequency fc, in Hertz)&#xA;ricker = @(fm,t) (1-2*pi^2*fm^2*t.^2) .* exp(-pi^2*fm^2.*t.^2);&#xA;fc = 20;&#xA;fs = ricker(fc, t-0.1 ); % Time-delayed Ricker wavelet (plot, if desired!)&#xA;&#xA;% --- Source location (positioned at 400, 600)&#xA;[~,sidx] = min(abs(x - 400));&#xA;[~,sidy] = min(abs(x - 600));&#xA;&#xA;%% The computational loop&#xA;% Initialize fields&#xA;p = zeros(nx+1,ny+1);&#xA;vx = zeros(nx+1,ny+1);&#xA;vy = zeros(nx+1,ny+1);&#xA;&#xA;% Stencil update locations&#xA;X = 1:nx;&#xA;Y = 1:ny;&#xA;&#xA;figure(1);&#xA;for a = 1:nt&#xA;    % (1) Inject source funtion&#xA;    p(sidx,sidy) = p(sidx,sidy) + dt*fs(a);&#xA;    &#xA;    % (2) Update p&#xA;    p(X+1,Y+1) = p(X+1,Y+1) - (dt*rho*vp^2)*((vx(X+1,Y) - vx(X,Y))/dx ...&#xA;                                            +(vy(X,Y+1) - vy(X,Y))/dy );&#xA;    &#xA;    % (3a) Update ux&#xA;    vx(X,Y) = vx(X,Y) - (dt/rho)*(p(X+1,Y+1) - p(X,Y+1))/dx;&#xA;    &#xA;    % (3b) Update uy&#xA;    vy(X,Y) = vy(X,Y) - (dt/rho)*(p(X+1,Y+1) - p(X+1,Y))/dy;&#xA;    &#xA;    % Display every 10th computation&#xA;    if (mod(a,10)==0)&#xA;        imagesc(x,y,p');&#xA;        axis equal;&#xA;        title(['Timestep = ', num2str(a), 'dt']);&#xA;        xlabel('x [m]');&#xA;        ylabel('y [m]');&#xA;        drawnow&#xA;    end&#xA;end&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="12155" LastEditorUserId="12155" LastEditDate="2021-10-06T08:40:49.720" LastActivityDate="2021-10-06T08:40:49.720" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22957" PostTypeId="1" CreationDate="2021-10-06T23:29:01.787" Score="2" ViewCount="161" Body="&lt;p&gt;I have a very basic doubt regarding what the tectonic plates mean. In Wiki article &lt;a href=&quot;https://en.wikipedia.org/wiki/Subduction&quot; rel=&quot;nofollow noreferrer&quot;&gt;Subduction&lt;/a&gt; is defined as:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at &lt;strong&gt;convergent boundaries&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and when I follow the link to &lt;a href=&quot;https://en.wikipedia.org/wiki/Convergent_boundary&quot; rel=&quot;nofollow noreferrer&quot;&gt;convergent boundary&lt;/a&gt; it is defined as:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more &lt;strong&gt;lithospheric plates&lt;/strong&gt; collide.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Now from what I know is that the tectonic plates comprise of oceanic and continental crust and convergent and divergent boundaries exist where two tectonic plates meet. So this subduction should &lt;strong&gt;only&lt;/strong&gt; happen where two or more &lt;strong&gt;major or minor&lt;/strong&gt; plates meet and not between continental crust and oceanic crust. So do plates sometime refer to crust as well and there are more minor and major plates which are still not defined.&lt;/p&gt;&#xA;&lt;p&gt;Edit: Is there a possibility of subduction between continental crust and oceanic crust of the same plate?(If answer is yes then these crusts can also be called plates).&lt;/p&gt;&#xA;" OwnerUserId="24596" LastEditorUserId="24596" LastEditDate="2021-10-07T13:49:45.423" LastActivityDate="2021-10-07T13:49:45.423" Title="Tectonic plates terminology" Tags="|plate-tectonics|tectonics|subduction|lithosphere|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22958" PostTypeId="2" ParentId="22957" CreationDate="2021-10-07T05:50:08.217" Score="1" Body="&lt;p&gt;Tectonic plates almost all comprise a mix of both oceanic and continental crust in different areas. The exceptions are all minor plates.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Where the edges of these plates spread apart you get divergent boundaries. These are always found in a single rock type; in continental crust these are the &lt;a href=&quot;https://en.wikipedia.org/wiki/Rift_valley&quot; rel=&quot;nofollow noreferrer&quot;&gt;rift valleys&lt;/a&gt; while at oceanic boundaries they are the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mid-ocean_ridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;mid-ocean ridges&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Where the edges come together you get convergent boundaries, these almost always involve subduction of denser plate material under lighter rock. The density split is often defined by rock type with dense basaltic oceanic crust being pushed under lighter continental rock along &lt;a href=&quot;https://en.wikipedia.org/wiki/Oceanic_trench&quot; rel=&quot;nofollow noreferrer&quot;&gt;deep ocean trenches&lt;/a&gt; but there are several places where older, cooler oceanic rock subducts below younger, hotter oceanic crust.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Where two continental plate boundaries collide neither can subduct because they are so much less dense than the underlying mantle so you get massive mountain ranges like the Himalaya. The Atlas, Alps, and Pyrennes are at the beginning of the process as Africa slowly closes the Mediterranean and crashes into Europe.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2021-10-07T05:50:08.217" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22959" PostTypeId="1" CreationDate="2021-10-07T06:20:32.580" Score="8" ViewCount="94" Body="&lt;p&gt;Does someone know where to find a (hopefully modern) version of the numerical code for solving the &lt;strong&gt;1D atmospheric thermal equilibrium model&lt;/strong&gt;, the one Syukuro Manabe &amp;amp; Richard T. Wetherald used in their seminal &lt;strong&gt;1967&lt;/strong&gt; publication in &lt;em&gt;J.Atmosph.Sciences&lt;/em&gt; ? (&lt;a href=&quot;https://doi.org/10.1175/1520-0469(1967)024%3C0241:TEOTAW%3E2.0.CO;2&quot; rel=&quot;noreferrer&quot;&gt;doi:10.1175/1520-0469(1967)024&amp;lt;0241:TEOTAW&amp;gt;2.0.CO;2&lt;/a&gt;). I guess with modern computers it's a matter of seconds to solve, and redo the calculations from their work, and I'ld be pleased to use this in my math for Earth sciences course, as an example (university, 2nd year).&lt;/p&gt;&#xA;" OwnerUserId="24597" LastActivityDate="2021-10-07T06:20:32.580" Title="Nobel prize Manabe's 1967 code for solving the 1D atmospheric thermal equilibrium model" Tags="|atmosphere-modelling|reproducibility|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22960" PostTypeId="1" CreationDate="2021-10-07T08:39:02.563" Score="7" ViewCount="101" Body="&lt;p&gt;Say a large forest fire took place. As I understand it, the smoke and ash would ride the wind and could be a health hazard even to people that are quite far away.&lt;/p&gt;&#xA;&lt;p&gt;My question is will it damage the soil itself and its agriculture, in these places that are some distance away? If so, what will that look like (to what extent), and what distance are we talking about?&lt;/p&gt;&#xA;&lt;p&gt;(This feels like a suspicious thing to ask, so let me just clarify that I'm asking this because this is a plot point in a book I'm writing, and I'd like to really understand what ramifications it would have outside of the specific place things are happening. I've asked &lt;a href=&quot;https://worldbuilding.stackexchange.com/questions/203651/a-huge-forest-native-almost-solely-to-elves-who-are-widely-regarded-with-hatred&quot;&gt;related questions&lt;/a&gt; in other places, but I think this is the most accurate.)&lt;/p&gt;&#xA;&lt;p&gt;Forgive me if the tags are inaccurate, I know nothing about any of this.&lt;/p&gt;&#xA;" OwnerUserId="24599" LastEditorDisplayName="user20559" LastEditDate="2021-10-09T09:09:41.853" LastActivityDate="2021-10-09T17:43:55.307" Title="What would be the effects of a large forest fire on soil in other places?" Tags="|geography|soil|agriculture|forest|wildfire|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22961" PostTypeId="2" ParentId="22960" CreationDate="2021-10-08T04:24:06.177" Score="3" Body="&lt;p&gt;Falling ash is usually not a concern for agriculture. But the particulate matter (smoke) can harm agricultural products.  Not through the soil, but by exposing the plants to smoke over long periods.  In particular, many vineyard owners are very unhappy with the recent increase in wildfire smoke in the west.  It taints their grapes and makes the wine less desirable or even worse, ruins the product altogether.  &lt;a href=&quot;https://www.nationalgeographic.com/environment/article/how-the-wests-wineries-are-battling-ruinous-wildfire-smoke&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Geographic&lt;/a&gt; mentions that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Last year, fires cost the wine industry in the United States $3.7 billion...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Wildfire smoke can travel very large distances (e.g. hemisphere), but smoke doesn't get trapped near the surface for long periods unless winds have decreased.  This means that wildfires within the same geographic region will be the source of smoke, ruling out trans-continental transport as a concern.  Smoke can easily pool in basins, where agriculture is prevalent, but the source of smoke is usually in the more mountainous areas around the basin.  The Columbia Basin is a good example, where you can have smoke pool for long periods that came from wildfires in the Cascade mountains.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2021-10-08T04:24:06.177" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22962" PostTypeId="2" ParentId="14259" CreationDate="2021-10-09T02:58:40.790" Score="-1" Body="&lt;p&gt;No, Volcanoes been erupting since the 80's. What happens is that topography determines where the lava will flow. A build up of material on western side, next eruption is more likely to deposit south or east; whatever blocks it.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-10-09T02:58:40.790" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22963" PostTypeId="2" ParentId="22960" CreationDate="2021-10-09T03:10:34.860" Score="3" Body="&lt;p&gt;After &lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_St._Helens&quot; rel=&quot;nofollow noreferrer&quot;&gt;Saint Helens&lt;/a&gt;, forest managers thought to harvest timber in the area and replant it because they assumed nothing would ever grow again. Instead they &lt;a href=&quot;https://www.mshslc.org/return-to-life/facts-and-research/faqs-on-return-to-life/were-any-trees-replanted-after-the-eruption/&quot; rel=&quot;nofollow noreferrer&quot;&gt;left it alone&lt;/a&gt; and the eruption epicenter is now the largest outdoor ecological restoration experiment. Scientists monitor it's rate and aspects of it's regeneration. Contrary to being a dead sterile environment the area is now teaming with colonizers and flowers not seen in decades; a beginning stage meadow is starting to form, Once tree seedling begin; in 20-40 years it'll be a open savannah; in 50-100 years a new woodland; in 150-20 years a new Forest may emerge. Forest fires fill a similar ecological role.....&lt;/p&gt;&#xA;&lt;p&gt;Fire’s &lt;a href=&quot;https://www.pacificbio.org/initiatives/fire/fire_ecology.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;role&lt;/a&gt; in dryland ecology is well known and researched, It substitutes the role normally reserved by &lt;a href=&quot;https://en.wikipedia.org/wiki/Decomposer&quot; rel=&quot;nofollow noreferrer&quot;&gt;decomposers&lt;/a&gt; like bacteria and fungi. In more humid and wetter environments they break down wood/plant matter into soluble nutrients for plant uptake. In xeric ecosystems this process is slower to nearly non-existant. So fire substitutes that task by charing material into water soluble ash. Whole types of forests use this method for regeneration.... and it has various benefits. In fact every species that lives in fire prone ecosystems must have the ability to withstand at least one fire or risk losing it's place in the community.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The fire itself converts aged woody debris and old trees into ash, this rich mineral laden &lt;a href=&quot;https://extension.uga.edu/publications/detail.html?number=B1142&amp;amp;title=Best%20Management%20Practices%20for%20Wood%20Ash%20as%20Agricultural%20Soil%20Amendment&quot; rel=&quot;nofollow noreferrer&quot;&gt;dressing will feed the next generation&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;It destroys weeds, by doing so provides available space for forbes, grasses and  such to grow which is more desireable and edible by herbivorous species such as deer and game species.&lt;/li&gt;&#xA;&lt;li&gt;The smoke of the fire is a chemical catalyst that may trigger dormant seeds in the soil to germinate, Now without vegetation above and the next rain, the seeds will grow competitor free. This is how Sequoia and eucalyptus regenerate.&lt;/li&gt;&#xA;&lt;li&gt;The fire produces huge volumes of Ethylene gas which is a plant growth catalyst.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="21028" LastEditorUserId="21028" LastEditDate="2021-10-09T17:43:55.307" LastActivityDate="2021-10-09T17:43:55.307" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22964" PostTypeId="2" ParentId="20733" CreationDate="2021-10-09T11:31:37.647" Score="12" Body="&lt;p&gt;Yes.&lt;/p&gt;&#xA;&lt;p&gt;Evapotranspiration (&lt;span class=&quot;math-container&quot;&gt;$ET$&lt;/span&gt;) can be calculated from latent heat (&lt;span class=&quot;math-container&quot;&gt;$LE$&lt;/span&gt;) by dividing by latent heat of vaporization (&lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt;)&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ ET = \frac{LE}{\lambda} $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;This assumes density of water equal to 1000 kg/m&lt;sup&gt;3&lt;/sup&gt;. Latent heat of vaporization is the amount of energy needed to change a unit mass of water&#xA;from liquid to water vapor. With LE and λ in units of MJ m&lt;sup&gt;-2&lt;/sup&gt; T&lt;sup&gt;-1&lt;/sup&gt; and MJ kg&lt;sup&gt;-1&lt;/sup&gt;, respectively, ET is in units of kg m&lt;sup&gt;-2&lt;/sup&gt; T&lt;sup&gt;-1&lt;/sup&gt; which is equal to depth of water in mm T&lt;sup&gt;-1&lt;/sup&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Latent heat of vaporization varies slightly with temperature, but is often set to 2.45 MJ kg&lt;sup&gt;-1&lt;/sup&gt; which is the value for an air temperature of 20 °C. Allen et al. (1998) also provides an equation for calculating λ with air temperature variation, see Annex 3 equation 3-1:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ \lambda = 2.501 - (2.361\times10^{-3})\times T_a$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$T_a$&lt;/span&gt; is air temperature in °C and &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt; is in MJ kg&lt;sup&gt;-1&lt;/sup&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Allen, R. G., Pereira, L. S., Raes, D., &amp;amp; Smith, M. (1998). Crop evapotranspiration - Guidelines for computing crop water requirements. FAO Irrigation and drainage  Paper 56. &lt;a href=&quot;http://www.fao.org/3/x0490e/x0490e00.htm&quot; rel=&quot;noreferrer&quot;&gt;http://www.fao.org/3/x0490e/x0490e00.htm&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24606" LastEditorUserId="24606" LastEditDate="2021-10-11T09:27:29.790" LastActivityDate="2021-10-11T09:27:29.790" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22966" PostTypeId="1" CreationDate="2021-10-10T15:29:41.243" Score="4" ViewCount="641" Body="&lt;p&gt;I posted this before on physics stack exchange, but it was deemed off topic, which is understandable, so I hope it won't be here.&lt;/p&gt;&#xA;&lt;p&gt;Recently, I stumbled upon an article by an individual named A.M. Tyurin, which challenges carbondating:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://web.archive.org/web/20200218162343/http://new.chronologia.org/volume2/turin2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://web.archive.org/web/20200218162343/http://new.chronologia.org/volume2/turin2.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It is in Russian, so here are some of the conclusions in English, on which I'd like to get a comment on:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;In the method of radiocarbon dating there is a clearly undefined assumption - the absolute content of &lt;sup&gt;13&lt;/sup&gt;C and &lt;sup&gt;12&lt;/sup&gt;C in the atmosphere is stable over the entire interval of using radiocarbon dating. This is the main secret of the radiocarbon community.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;The Delta &lt;sup&gt;14&lt;/sup&gt;C plot and its derivative - the calibration curve of radiocarbon dating, reflect the variations in &lt;sup&gt;14&lt;/sup&gt;C not in the atmosphere, but in the CO&lt;sub&gt;2&lt;/sub&gt; atmosphere. This is the main lie of the radiocarbon community&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;The system errors are &amp;quot;inscribed&amp;quot; into the calibration curve: dating by the Libby method (they were included in the calibration curve through dendrochronological scales built taking into account the dating by the Libby method); incorrect manipulations with the values ​​of the Delta &lt;sup&gt;14&lt;/sup&gt;C graph (manipulations were performed in order to &amp;quot;take into account&amp;quot; the influence of anthropogenic factors on the change in the CO&lt;sub&gt;2&lt;/sub&gt; content in the atmosphere); associated with variations of &lt;sup&gt;13&lt;/sup&gt;C in the CO&lt;sub&gt;2&lt;/sub&gt; atmosphere. There are also systemic errors in the estimates of the contribution of the shape of the calibration curve to the dating accuracy. This is the great mystery of the calibration curve.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I am interested in seeing a comment on these claims and maybe on the wider context of the article as well, if possible.&lt;/p&gt;&#xA;&lt;p&gt;I hope my question is clear enough, thanks.&lt;/p&gt;&#xA;" OwnerUserId="24612" LastEditorUserId="2470" LastEditDate="2022-08-08T05:34:43.430" LastActivityDate="2022-08-08T05:34:43.430" Title="Is Radiocarbon dating flawed?" Tags="|geology|sedimentology|paleontology|carbon|archaeology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="22967" PostTypeId="1" CreationDate="2021-10-11T10:23:19.463" Score="1" ViewCount="117" Body="&lt;p&gt;I'm looking for some of the most comprehensive or significant articles on the Mozambique Belt in East Africa.  If anyone can recommend some specific papers regarding the Geological history of the belt I would greatly appreciate it.&lt;/p&gt;&#xA;" OwnerUserId="24615" LastEditorUserId="2470" LastEditDate="2021-10-22T17:52:02.907" LastActivityDate="2021-10-22T17:52:02.907" Title="How was the Mozambique Belt formed" Tags="|geology|volcanic-eruption|east-africa-rift|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22970" PostTypeId="1" CreationDate="2021-10-11T19:34:09.207" Score="1" ViewCount="59" Body="&lt;p&gt;Navier's equations of motion in seismic have 3 solutions, according to how it is resolved (boundary conditions):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;for V&lt;sub&gt;p&lt;/sub&gt; (compression waves)&lt;/li&gt;&#xA;&lt;li&gt;for V&lt;sub&gt;s&lt;/sub&gt; (shear waves)&lt;/li&gt;&#xA;&lt;li&gt;for V&lt;sub&gt;r&lt;/sub&gt; (Rayleigh waves)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I know the boundary conditions for V&lt;sub&gt;r&lt;/sub&gt;, that is the half-space (null stress at the surface and null displacements and stress at infinite depth).&lt;/p&gt;&#xA;&lt;p&gt;What would be the boundary conditions for V&lt;sub&gt;p&lt;/sub&gt; and V&lt;sub&gt;s&lt;/sub&gt; solutions and why do they derivate for infinite medium and not half-space? What does an infinite medium imply?&lt;/p&gt;&#xA;" OwnerUserId="24613" LastEditorUserId="543" LastEditDate="2021-10-12T15:21:08.173" LastActivityDate="2021-10-12T15:21:08.173" Title="What are the boundary conditions for Navier's Equations of motion in seismic?" Tags="|geophysics|waves|seismic|mathematics|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22971" PostTypeId="1" CreationDate="2021-10-12T14:58:27.450" Score="3" ViewCount="318" Body="&lt;p&gt;Apologies, this is a simple question.&#xA;But I just want to make sure I am calculating the mean, annual maximum temperatures correctly.&lt;/p&gt;&#xA;&lt;p&gt;I have monthly temperature data from 1980 - 2019. In order to get the mean annual maximum temperatures based on monthly averages, do you:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;get the maximum temperature for each year (1980, then 1981 etc.). now there is 1 maximum temperature for each year (so 39 years worth of maximum temperatures)&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;now that there are 39 years of maximum temperatures, do you then take the average of that to get the mean annual max temps?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Is that the correct way to calculate the mean annual maximum temperatures from monthly temperature data?&lt;/p&gt;&#xA;" OwnerUserId="24625" LastEditorUserId="2470" LastEditDate="2021-10-12T15:25:58.140" LastActivityDate="2021-10-12T15:25:58.140" Title="How to calculate mean annual maximum temperatures from monthly temperature values?" Tags="|climate|temperature|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22972" PostTypeId="1" CreationDate="2021-10-12T21:03:32.353" Score="1" ViewCount="41" Body="&lt;p&gt;I'm trying to find to original source (especially high quality version) of this conservation seismic map. I know that it probably came from USGS (or not) but looks like it out of print? I tried to search for the map on USGS.gov but no result so far. IS there  anything else I'm missing?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/uenNG.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uenNG.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24629" LastEditorUserId="24629" LastEditDate="2021-10-12T21:10:28.843" LastActivityDate="2021-11-11T23:07:25.603" Title="Source for USGS (probably not) seismic map of La Habra, California (Publication Date April 15, 1998)" Tags="|seismology|earth-observation|mapping|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22973" PostTypeId="1" AcceptedAnswerId="22978" CreationDate="2021-10-12T22:25:18.043" Score="2" ViewCount="1253" Body="&lt;p&gt;What is the difference between surface specific humidity and surface relative humidity (it's wetter and dryer respectively)? The trends, according to the latest IPCC report, are opposite for the two, and I'd like to know what it entails.&lt;/p&gt;&#xA;" OwnerUserId="22632" LastActivityDate="2021-10-14T06:07:54.883" Title="What is the difference between surface specific humidity and surface relative humidity?" Tags="|climate-change|humidity|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22974" PostTypeId="1" AcceptedAnswerId="22980" CreationDate="2021-10-12T22:47:22.157" Score="22" ViewCount="10962" Body="&lt;p&gt;Why is the Arctic melting, but the Antarctic doing great? That's what the latest IPCC report says (p. 2-192 of the Physical Science Basis provides a time series), but it says nothing, unless I missed it, on the causes of such a discrepancy. It's same ice, isn't it? Why is Antarctic ice more heatproof?&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/lWuH3.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;EDIT: I've found the answer in the IPCC report (AR6 WGI), and it's even fairly intelligible (unlike much of the rest of the report). Start reading from page 7-80, if you're interested&lt;/p&gt;&#xA;" OwnerUserId="22632" LastEditorUserId="22632" LastEditDate="2021-12-16T01:32:11.193" LastActivityDate="2021-12-16T01:32:11.193" Title="Why is the Arctic melting, but the Antarctic doing great?" Tags="|climate-change|cryosphere|" AnswerCount="5" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="22975" PostTypeId="2" ParentId="22972" CreationDate="2021-10-12T23:04:12.543" Score="2" Body="&lt;p&gt;This map appears to have been produced by the California Geological Survey (a state agency) as a GIS cover incorporating two specific coverage layers, namely, 1) Seismic Hazards Program - Landslide Zones, and 2) Seismic Hazards Program - Liquefaction Zones.  The map viewer for selecting GIS layers and observing available mapped information is can be accessed &lt;a href=&quot;https://maps.conservation.ca.gov/cgs/DataViewer/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. An extract is shown below. Simply go to site and select the coverages you wish to see...&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Z3b4B.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Z3b4B.png&quot; alt=&quot;La Habra extract CGS data viewer&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24630" LastActivityDate="2021-10-12T23:04:12.543" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22976" PostTypeId="2" ParentId="22974" CreationDate="2021-10-13T01:33:25.150" Score="67" Body="&lt;p&gt;Not quite. The report actually shows an increase in &lt;em&gt;extent&lt;/em&gt;, but not the volume, of sea-ice around Antarctica. That sounds good, but the data appendix in the report shows the Antarctic continental ice-sheet is shedding ice so fast during the summer months, and into the Autumn, that the ice can't melt or migrate away during the season. When the winter freeze comes the ice already in the water is making the ocean surface cooler and nucleating sea-ice growth farther off shore than it should be. We're seeing a larger but thinner sheet of ice around the Antarctic which can seem unaffected by climate change, but its ice is actually melting at a rate comparable to the Arctic.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="10735" LastEditDate="2021-10-15T08:26:04.703" LastActivityDate="2021-10-15T08:26:04.703" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22977" PostTypeId="2" ParentId="22973" CreationDate="2021-10-13T01:46:17.603" Score="2" Body="&lt;p&gt;Specific humidity is a simple percentage measurement of the total water in the atmosphere, the other term for this is the absolute humidity. Relative humidity on the other hand is the amount of water in the atmosphere as a percentage of the maximum carrying capacity of the air. The carrying capacity of air is temperature dependent, warmer air can hold more water vapour than cooler air so the absolute humidity can rise while the relative humidity actually drops as a body of air warms. The IPCC are probably looking at the world average and the warming trend should be increasing evaporation but carrying capacity is going up faster than atmospheric moisture levels.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2021-10-13T01:46:17.603" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22978" PostTypeId="2" ParentId="22973" CreationDate="2021-10-13T08:29:01.693" Score="5" Body="&lt;p&gt;Let's put it a different way:&lt;/p&gt;&#xA;&lt;p&gt;Specific humidity is how much actual water (vapor) is in the air.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;More warmth tends to mean more evaporation.&lt;/li&gt;&#xA;&lt;li&gt;Warming air also raises the limit of how much water it can hold in total.  So a second reason specific humidity can go up is that it raises the cap level.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;On the other hand, relative humidity is just a measure of how &lt;em&gt;full&lt;/em&gt; the air is.  It's really not that representative of how much water is truly in the air.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;If the cap level goes way up, but the amount of actual water only goes up a little... it's actually less near full than before.  Think a mostly full bowl compared to a quarter-full bathtub... there's more water in the bathtub, but it's less relatively full.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Hopefully this next graph, showing the weather from Duluth, MN the past couple weeks, can help show the point:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/i2efk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/i2efk.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The green and pink lines fluctuate in an almost perfectly opposite pattern, almost like heartbeat consistency, just about touching most days, then separating far apart.  That's the daily cycle, and similar over most of the world much of the year... and it's mainly just all caused by temperature change; in the daytime it gets hot, so the air can hold more water, but the amount of actual water (in blue) really doesn't change much each day usually... meaning it's less full.  At night the air cools down, &amp;quot;shrinking the container&amp;quot;, until it's just about saturated again around dawn, despite not losing much of any water.&lt;/p&gt;&#xA;&lt;p&gt;RH is honestly a lame moisture measure, meteorologists really don't use it too much.  Because it doesn't mean much, it really just reflects that temperature fluctuates each day.  And that's not ground breaking information!  When forecasting severe weather or precipitation or snow or tropical cyclones... it tells us almost nothing of use.&lt;/p&gt;&#xA;&lt;p&gt;Dew point, which is probably the most used absolute measure of water... is much more informative to us.  It really focuses in on how much water is in the air (which is important for forecasting almost everything weather-wise)&lt;/p&gt;&#xA;&lt;p&gt;And notice if anything, that dewpoint is going the same way as temperature instead of the opposite.&lt;/p&gt;&#xA;&lt;p&gt;So this graph shows relative and absolute humidity typically fluctuate in two opposite ways to the temperature.&lt;/p&gt;&#xA;&lt;p&gt;And so hopefully it makes sense that if it's getting warmer, those opposing trends would be a reasonable result.  The overall water goes up... the &amp;quot;fullness percentage&amp;quot; may well still go down.&lt;/p&gt;&#xA;&lt;p&gt;If total moisture goes up a bit, but the atmosphere's moisture cap goes up much more, it would mean RH and AH change in opposite directions.  Since evaporation requires more energy, meaning for weather the dew point is much slower to change than temperature... it lines up that this would be the trend.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Absolute and relative humidity do both &amp;quot;measure&amp;quot; water vapor in the air.  But because one, RH, really is more a (inverted) temperature measurement masquerading as a moisture measurement, rather than truly tracking water changes... they still can and very often do move in opposite ways.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;hr&gt;&#xA;&lt;p&gt;(Just a side note: absolute humidity can often be a bit more stable and independent from temperature, more so than this graph suggests.  Wind changes like fronts and sea breezes can mean more connected movement, because different airmasses are coming in.  It's fall in MN, so there's some of that going on.&lt;br /&gt;&#xA;But hopefully graphs for other areas can help you explore the trend more and be convinced of the main ideas: (&lt;a href=&quot;https://www.wrh.noaa.gov/zoa/getobext.php?sid=KMCO&amp;amp;num=336&quot; rel=&quot;nofollow noreferrer&quot;&gt;Orlando&lt;/a&gt;, &lt;a href=&quot;https://www.wrh.noaa.gov/zoa/getobext.php?sid=KSAT&amp;amp;num=336&quot; rel=&quot;nofollow noreferrer&quot;&gt;San Antonio&lt;/a&gt;, &lt;a href=&quot;https://www.wrh.noaa.gov/zoa/getobext.php?sid=KSEA&amp;amp;num=336&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seattle&lt;/a&gt;, &lt;a href=&quot;https://www.wrh.noaa.gov/zoa/getobext.php?sid=PGUM&amp;amp;num=336&quot; rel=&quot;nofollow noreferrer&quot;&gt;Phoenix&lt;/a&gt;, &lt;a href=&quot;https://www.wrh.noaa.gov/zoa/getobext.php?sid=HKJK&amp;amp;num=336&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nairobi Kenya&lt;/a&gt;, &lt;a href=&quot;https://www.wrh.noaa.gov/zoa/getobext.php?sid=OIII&amp;amp;num=336&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tehran Iran&lt;/a&gt;, &lt;a href=&quot;https://www.wrh.noaa.gov/zoa/getobext.php?sid=WSSS&amp;amp;num=336&quot; rel=&quot;nofollow noreferrer&quot;&gt;Singapore&lt;/a&gt;, &lt;a href=&quot;https://www.wrh.noaa.gov/zoa/getobext.php?sid=YSSY&amp;amp;num=336&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sydney Australia&lt;/a&gt;, &lt;a href=&quot;https://www.wrh.noaa.gov/zoa/getobext.php?sid=PGUA&amp;amp;num=336&quot; rel=&quot;nofollow noreferrer&quot;&gt;Guam&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2021-10-14T06:07:54.883" LastActivityDate="2021-10-14T06:07:54.883" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22979" PostTypeId="2" ParentId="22974" CreationDate="2021-10-13T08:31:48.670" Score="36" Body="&lt;p&gt;The  Antarctic is &lt;strong&gt;not&lt;/strong&gt; &amp;quot;doing great&amp;quot;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.antarcticglaciers.org/glaciers-and-climate/changing-antarctica/antarctic-ice-sheet-surface-mass-balance/&quot; rel=&quot;noreferrer&quot;&gt;Antarctica moved from a weakly negative mass balance in the 1990s to a faster rate of mass loss at a rate of between -45 and -120 gigatonnes per year.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="5396" LastEditorUserId="5396" LastEditDate="2021-10-15T12:17:15.337" LastActivityDate="2021-10-15T12:17:15.337" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22980" PostTypeId="2" ParentId="22974" CreationDate="2021-10-13T14:29:01.027" Score="7" Body="&lt;p&gt;The IPCC says (&lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/02/ar4-wg2-chapter15-1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;PDF page 4, report page 656 of an older report&lt;/a&gt;):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Increased melting of Arctic glaciers and the Greenland ice sheet, but thickening of the Antarctic ice sheet due to increased precipitation, were projected.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Climate change is leading to &lt;a href=&quot;https://www.epa.gov/climate-indicators/climate-change-indicators-heavy-precipitation&quot; rel=&quot;nofollow noreferrer&quot;&gt;increased precipitation&lt;/a&gt;. (Short version: Warm air picks up more humidity.) In places where it is cold enough, that precipitation is snow/ice.&lt;/li&gt;&#xA;&lt;li&gt;The Antarctic is significantly &lt;a href=&quot;https://climatekids.nasa.gov/polar-temperatures/&quot; rel=&quot;nofollow noreferrer&quot;&gt;colder&lt;/a&gt; than the Arctic--because land can get colder than water in the first place and also because it has higher elevations. In this case, the Antarctic is cold enough that it doesn't melt so much, whereas the Arctic is warmer and melts more.&lt;/li&gt;&#xA;&lt;li&gt;Once it gets warm and starts melting, melting (and rain) makes local temperatures warmer and leads to &lt;a href=&quot;https://www.bbc.com/news/science-environment-47485847&quot; rel=&quot;nofollow noreferrer&quot;&gt;more melting&lt;/a&gt;, but snow makes local temperatures colder, i.e. &lt;a href=&quot;https://tos.org/oceanography/article/increased-arctic-precipitation-slows-down-sea-ice-melt-and-surface-warming&quot; rel=&quot;nofollow noreferrer&quot;&gt;less melting&lt;/a&gt; (short version: liquid surface water makes ice which is dark-colored and radiates sunlight as heat, snow is light-colored and radiates sunlight as light).&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;This doesn't mean that the Antarctic is safe forever, if the global temperatures increase enough then even a locally colder temperature won't be cold enough to prevent melting...and once melting starts, it can create a feedback loop which increases the speed of melting.&lt;/p&gt;&#xA;&lt;p&gt;You can see this kind of local variation within Antarctica as well. East Antarctica is &lt;a href=&quot;https://en.wikipedia.org/wiki/East_Antarctica&quot; rel=&quot;nofollow noreferrer&quot;&gt;higher&lt;/a&gt; (and colder, for reasons above) than West Antarctica --and the eastern side has been (slightly) gaining ice while the &lt;a href=&quot;https://grace.jpl.nasa.gov/resources/31/antarctic-ice-loss-2002-2020/&quot; rel=&quot;nofollow noreferrer&quot;&gt;western side has been losing ice&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="13310" LastEditorUserId="13310" LastEditDate="2021-10-16T00:41:07.213" LastActivityDate="2021-10-16T00:41:07.213" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22981" PostTypeId="2" ParentId="22974" CreationDate="2021-10-13T15:00:21.213" Score="1" Body="&lt;p&gt;In the absence of a worldwide warming trend, there is a large scale oscillation, the &lt;strong&gt;thermal bipolar see-saw&lt;/strong&gt;. When the Arctic cools, the Antarctic warms and vice versa. With a worldwide warming trend, even if both are warming, the oscillation will still cause one to race ahead of the other, then switch places.&lt;/p&gt;&#xA;&lt;p&gt;See the article &lt;a href=&quot;https://www.nature.com/articles/ngeo1026&quot; rel=&quot;nofollow noreferrer&quot;&gt;Expression of the bipolar see-saw in Antarctic climate records during the last deglaciation&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Other differences besides those mentioned in other answers:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Due to weird chemistry, increasing CO&lt;sub&gt;2&lt;/sub&gt; over Antarctica causes a reverse greenhouse effect - it cools the surface! See the article &lt;a href=&quot;https://www.nature.com/articles/s41612-018-0031-y&quot; rel=&quot;nofollow noreferrer&quot;&gt;Unmasking the negative greenhouse effect over the Antarctic Plateau&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;There is a lot of vulcanism under Antarctica. We don't know how much melting to attribute to that.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="24641" LastEditorUserId="2958" LastEditDate="2021-10-14T15:25:58.890" LastActivityDate="2021-10-14T15:25:58.890" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="22982" PostTypeId="1" CreationDate="2021-10-13T15:55:01.447" Score="1" ViewCount="40" Body="&lt;p&gt;Currently, I've started working on a geophysics project. More specifically, I'm trying to find gas and oil reservoirs in SEGY files using deep learning. I've been reading about seismic reflection methods and watched a series of lessons at &lt;a href=&quot;https://www.youtube.com/user/IRISEnO&quot; rel=&quot;nofollow noreferrer&quot;&gt;IRIS Youtube channel&lt;/a&gt;, but something isn't very clear to me yet, and this leads to my question. Is there some kind of relationship between two different rock layers? I mean, something along the lines &amp;quot;after a layer of shale it's more likely that I find an oil reservoir than after a layer of limestones&amp;quot;.&#xA;In summary, what I'd like to know is whether or not there is some kind of &amp;quot;common layer ordering&amp;quot;, or pattern, in the subsurface, even though if it's not 100% deterministic.&lt;/p&gt;&#xA;" OwnerUserId="24642" LastActivityDate="2021-10-13T15:55:01.447" Title="Are there specific layers in the subsurface that come before gas or oil?" Tags="|seismic|geologic-layers|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22986" PostTypeId="2" ParentId="22974" CreationDate="2021-10-14T01:29:14.147" Score="6" Body="&lt;p&gt;The Antarctic has a feature which the Arctic doesn't - It has the Southern Ocean. This ocean sweeps around Antarctica, to keep the hot air out and the cold air in. Although global warming increases global ocean temperature, Antarctica is less affected due to its 'shield', the Sourthern Ocean.&lt;/p&gt;&#xA;&lt;p&gt;How it works is that the ocean moves rapidly in a circle around Antarctica, around 100km off from the land, using the wind as a 'barrier'. You can see that many hot air currents 'bounce' off.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CcUc4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CcUc4.png&quot; alt=&quot;You can see from here that the wind stops the hot air effectively.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24651" LastEditorUserId="24651" LastEditDate="2021-10-14T22:11:37.323" LastActivityDate="2021-10-14T22:11:37.323" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="22987" PostTypeId="2" ParentId="14809" CreationDate="2021-10-14T02:08:51.423" Score="8" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WvOM5.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WvOM5.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;Here my wife holds a globe with the moon in view.  I carefully processed in a bit-mode to find the curve of light on the globe and drew perpendicular lines.  Plainly we can see that the moon-lite side is facing the sun in the same direction of my globe.&lt;/p&gt;&#xA;&lt;p&gt;The illusion is due to the sun being so far that the difference in angles shown in the drawing would not be noticeable. Imagine two planes where both of them contain the sun and moon, the level plane would be how an observer would see the moon when both the moon and the sun were at the horizon. The tilted plane is how an observer would normally see the moon high in the sky even though the sun was at the horizon during sunset. The observers on both planes would see the same half-moon shape even though the relative heights in the sky vary greatly.  This construct might only work for quarter moon illuminated.&lt;a href=&quot;https://i.stack.imgur.com/S2QrE.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/S2QrE.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24649" LastEditorUserId="24649" LastEditDate="2021-10-28T18:52:01.947" LastActivityDate="2021-10-28T18:52:01.947" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="22988" PostTypeId="2" ParentId="22944" CreationDate="2021-10-14T03:25:47.497" Score="1" Body="&lt;p&gt;To begin with, the formation of the Himalayas was never volcanic which is why you don't find volcanic rocks in the Himalayas. As for the subducting Indian oceanic plate (which contained Indian continental crust) that volcanism can be found in Tibet and the eastern Himalayas, in far northern Myanmar. This would suggest an oblique component to the subduction of the Indian Plate relative to the Eurasian Plate.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2021-10-14T03:25:47.497" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22989" PostTypeId="1" AcceptedAnswerId="22991" CreationDate="2021-10-14T07:33:04.110" Score="8" ViewCount="137" Body="&lt;p&gt;I need data regarding water temperature of Mediterranean Sea according to changes in depth. I couldn't find these data in the &lt;a href=&quot;https://www.copernicus.eu/en/copernicus-services/marine&quot; rel=&quot;noreferrer&quot;&gt;Copernicus Marine&lt;/a&gt; website, so I'd like to know if you know of any database where I can find this type of data, and if you think it's even possible to obtain them.&lt;/p&gt;&#xA;" OwnerUserId="24655" LastEditorUserId="111" LastEditDate="2021-10-16T18:56:40.297" LastActivityDate="2022-02-25T21:43:01.167" Title="Where to find reliable water temperature?" Tags="|oceanography|temperature|water|database|mediterranean|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22990" PostTypeId="1" CreationDate="2021-10-14T13:31:41.543" Score="1" ViewCount="68" Body="&lt;p&gt;I am a lyaman of Geography, and working on a project to calcuate&#xA;x,y (from a rectangle coordinate system) to Lat,Long&#xA;I searched on the net, and fell complete lost in the big world of geometry, geography, and mathe.&#xA;Could someone please recommend books/pdf on learning these stuffs from a newbie?&#xA;Thanks!&lt;/p&gt;&#xA;" OwnerUserId="24659" LastActivityDate="2021-10-19T03:38:45.523" Title="Recommend books on Lat Long" Tags="|mathematics|geometry|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="22991" PostTypeId="2" ParentId="22989" CreationDate="2021-10-15T02:40:41.003" Score="9" Body="&lt;p&gt;The &lt;a href=&quot;https://www.metoffice.gov.uk/hadobs/index.html&quot; rel=&quot;noreferrer&quot;&gt;Met Office Hadley Centre&lt;/a&gt; provides global quality controlled ocean temperature and salinity profiles and monthly long-term objectively analyzed global fields with a one degree spatial resolution (&lt;a href=&quot;https://doi.org/10.1002/2013JC009067&quot; rel=&quot;noreferrer&quot;&gt;Good et al., 2013&lt;/a&gt;). The most recent EN4 dataset (&lt;a href=&quot;https://www.metoffice.gov.uk/hadobs/en4/&quot; rel=&quot;noreferrer&quot;&gt;https://www.metoffice.gov.uk/hadobs/en4/&lt;/a&gt;) includes objectively analyzed fields formed from profile data with uncertainty estimates. The available data extend from the year 1900 to the present and there are separate files for each month. Good et al. (2013) used a simple analysis correction (&lt;a href=&quot;https://doi.org/10.1016/j.jmarsys.2005.11.019&quot; rel=&quot;noreferrer&quot;&gt;Ingleby &amp;amp; Huddleston, 2007&lt;/a&gt;) optimal interpolation methodology to analyze global historical observations that had been methodically quality controlled. The analysis fields are constructed by combining a background field (the analysis field of the previous month) with the quality controlled profiles from the month being analyzed.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3TvhT.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3TvhT.png&quot; alt=&quot;Surface temperature anomaly &quot; /&gt;&lt;/a&gt;&#xA;Source: Met Office Hadley Centre&lt;/p&gt;&#xA;&lt;p&gt;Alternatively, you can get the data from &lt;a href=&quot;https://www.ncei.noaa.gov/products/world-ocean-atlas&quot; rel=&quot;noreferrer&quot;&gt;NOAA World Ocean Atlas&lt;/a&gt; using the &lt;a href=&quot;https://www.nodc.noaa.gov/cgi-bin/OC5/SELECT/woaselect.pl?parameter=1&quot; rel=&quot;noreferrer&quot;&gt;WOA select tool&lt;/a&gt;. It provides fields for all depths and several fields. The methodology is slightly different but quite similar (&lt;a href=&quot;https://accession.nodc.noaa.gov/NCEI-WOA18&quot; rel=&quot;noreferrer&quot;&gt;Boyer et al., 2018&lt;/a&gt;; &lt;a href=&quot;https://www.ncei.noaa.gov/sites/default/files/2021-03/woa18_vol1.pdf&quot; rel=&quot;noreferrer&quot;&gt;Locarnini et al, 2019&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;Ref:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Boyer, Tim P.; Garcia, Hernan E.; Locarnini, Ricardo A.; Zweng, Melissa M.; Mishonov, Alexey V.; Reagan, James R.; Weathers, Katharine A.; Baranova, Olga K.; Seidov, Dan; Smolyar, Igor V. (2018). World Ocean Atlas 2018.&lt;/li&gt;&#xA;&lt;li&gt;Good, S.A.; Martin, M.J.; Rayner, N.A. EN4: Quality controlled ocean temperature and salinity profiles and monthly objective analyses with uncertainty estimates. J. Geophys. Res. Oceans 2013, 118, 6704–6716.&lt;/li&gt;&#xA;&lt;li&gt;Ingleby, B.; Huddleston, M. Quality control of ocean temperature and salinity profiles—Historical and real-time data. J. Mar. Syst. 2007, 65, 158–175.&lt;/li&gt;&#xA;&lt;li&gt;Locarnini, R.A., A.V. Mishonov, O.K. Baranova, T.P. Boyer, M.M. Zweng, H.E. Garcia, J.R. Reagan, D. Seidov, K.W. Weathers, C.R. Paver, and I.V. Smolyar (2019). World Ocean Atlas 2018, Volume 1: Temperature. A. Mishonov, Technical Editor. NOAA Atlas NESDIS 81, 52pp.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="111" LastActivityDate="2021-10-15T02:40:41.003" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22994" PostTypeId="1" CreationDate="2021-10-15T16:36:21.910" Score="2" ViewCount="75" Body="&lt;p&gt;I am having trouble interpreting the output of wgrib2.  I was expecting this command to produce a set of four measurements: one for each corner of a box at the specified pressure level.  Instead I got a large amount of data.  I don't understand what I am looking at, and was hoping someone could tell me how to interpret it.&lt;/p&gt;&#xA;&lt;p&gt;Here is a sample out from a grib2 file.  It was produced with the following command:&lt;/p&gt;&#xA;&lt;p&gt;wgrib2 test.grib2 -set_lev '850 mb' -undefine out-box 0:1 0:40 -match ':TMP:' -csv -&lt;/p&gt;&#xA;&lt;p&gt;16:8032172&amp;quot;2021-10-15 06:00:00&amp;quot;,&amp;quot;2021-10-15 10:00:00&amp;quot;,&amp;quot;TMP&amp;quot;,&amp;quot;850 mb&amp;quot;,1,39,180.817&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;2021-10-15 06:00:00&amp;quot;,&amp;quot;2021-10-15 10:00:00&amp;quot;,&amp;quot;TMP&amp;quot;,&amp;quot;850 mb&amp;quot;,1.25,39,180.667&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;2021-10-15 06:00:00&amp;quot;,&amp;quot;2021-10-15 10:00:00&amp;quot;,&amp;quot;TMP&amp;quot;,&amp;quot;850 mb&amp;quot;,1,39.25,180.787&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;2021-10-15 06:00:00&amp;quot;,&amp;quot;2021-10-15 10:00:00&amp;quot;,&amp;quot;TMP&amp;quot;,&amp;quot;850 mb&amp;quot;,1.25,39.25,180.707&lt;/p&gt;&#xA;&lt;p&gt;:d=2021101506:TMP:850 mb:4 hour fcst:&lt;/p&gt;&#xA;&lt;p&gt;26:15798999&amp;quot;2021-10-15 06:00:00&amp;quot;,&amp;quot;2021-10-15 10:00:00&amp;quot;,&amp;quot;TMP&amp;quot;,&amp;quot;850 mb&amp;quot;,1,39,198.943&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;2021-10-15 06:00:00&amp;quot;,&amp;quot;2021-10-15 10:00:00&amp;quot;,&amp;quot;TMP&amp;quot;,&amp;quot;850 mb&amp;quot;,1.25,39,196.703&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;2021-10-15 06:00:00&amp;quot;,&amp;quot;2021-10-15 10:00:00&amp;quot;,&amp;quot;TMP&amp;quot;,&amp;quot;850 mb&amp;quot;,1,39.25,199.273&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;2021-10-15 06:00:00&amp;quot;,&amp;quot;2021-10-15 10:00:00&amp;quot;,&amp;quot;TMP&amp;quot;,&amp;quot;850 mb&amp;quot;,1.25,39.25,197.793&lt;/p&gt;&#xA;&lt;p&gt;:d=2021101506:TMP:850 mb:4 hour fcst:&lt;/p&gt;&#xA;&lt;p&gt;36:24377875&amp;quot;2021-10-15 06:00:00&amp;quot;,&amp;quot;2021-10-15 10:00:00&amp;quot;,&amp;quot;TMP&amp;quot;,&amp;quot;850 mb&amp;quot;,1,39,202.97&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;2021-10-15 06:00:00&amp;quot;,&amp;quot;2021-10-15 10:00:00&amp;quot;,&amp;quot;TMP&amp;quot;,&amp;quot;850 mb&amp;quot;,1.25,39,203.69&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;2021-10-15 06:00:00&amp;quot;,&amp;quot;2021-10-15 10:00:00&amp;quot;,&amp;quot;TMP&amp;quot;,&amp;quot;850 mb&amp;quot;,1,39.25,202.98&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;2021-10-15 06:00:00&amp;quot;,&amp;quot;2021-10-15 10:00:00&amp;quot;,&amp;quot;TMP&amp;quot;,&amp;quot;850 mb&amp;quot;,1.25,39.25,203.12&lt;/p&gt;&#xA;&#xA;" OwnerUserId="18975" LastEditorUserId="22648" LastEditDate="2021-10-18T17:14:16.333" LastActivityDate="2021-10-18T17:14:16.333" Title="What is grib2 telling me?" Tags="|meteorology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="22997" PostTypeId="2" ParentId="14809" CreationDate="2021-10-15T20:05:54.900" Score="0" Body="&lt;p&gt;EDIT: I am making two simplifications which still display the &amp;quot;anomaly&amp;quot;.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;I consider the 2 dimensional case.&lt;/li&gt;&#xA;&lt;li&gt;Sunbeams (blue lines) are nearly parallel, since the Sun is so far away.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;At sunset the observer can see the unlit part of the Moon at the bottom, so it appears illuminated from above.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/mz7U1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mz7U1.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastEditorUserId="6535" LastEditDate="2021-10-20T02:19:57.757" LastActivityDate="2021-10-20T02:19:57.757" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="22998" PostTypeId="1" AcceptedAnswerId="23000" CreationDate="2021-10-15T21:44:35.200" Score="5" ViewCount="1083" Body="&lt;p&gt;For this, I am using python to plot and manipulate the data.&lt;/p&gt;&#xA;&lt;p&gt;I am using reanalysis data in a netcdf format for this problem.&lt;/p&gt;&#xA;&lt;p&gt;The data includes geopotential, for which I estimated the geopotential height through the following.&lt;/p&gt;&#xA;&lt;p&gt;The netcdf variable for geopotential is as follows:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;&amp;lt;class 'netCDF4._netCDF4.Variable'&amp;gt;&#xA;int16 z(time, level, latitude, longitude)&#xA;    scale_factor: 0.9163788350787961&#xA;    add_offset: 28797.397523473086&#xA;    _FillValue: -32767&#xA;    missing_value: -32767&#xA;    units: m**2 s**-2&#xA;    long_name: Geopotential&#xA;    standard_name: geopotential&#xA;unlimited dimensions: &#xA;current shape = (1, 2, 51, 101)&#xA;filling on&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;I then proceeded to extract this variable as follows, and calculate the geopotential height by dividing the variable geop by &lt;span class=&quot;math-container&quot;&gt;$g_{o} = 9.81$&lt;/span&gt;. I then assigned this to a variable &lt;span class=&quot;math-container&quot;&gt;$Z$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;geop    = file.variables['z'][:]&#xA;g = 9.81&#xA;Z = geop/g # Geopotential Height&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Now I plot this variable and the resulting plot is shown below (Units in geopotential meters):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cfQbs.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cfQbs.png&quot; alt=&quot; &quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Through the hydrostatic equation &lt;span class=&quot;math-container&quot;&gt;$ dp = -\rho gdz $&lt;/span&gt;, I tried directly calculating for p. by doing the following calculation:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;Zl=Z[0,level==1000,:,:]&#xA;rho = 1.25&#xA;g = 9.81&#xA;dp = -1 *(rho*g*Zl)  # employing the hydrostatic approximation&#xA;dp&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Which gives me these values as seen below and in the plot:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;masked_array(&#xA;  data=[[[410.9842133392113, 307.8915943928496, 209.38086962187754, ...,&#xA;          187.6168722887587, 256.3452849196665, 289.56401769127297],&#xA;         [650.3881840035501, 506.05851747863653, 360.58337740988014,&#xA;          ..., 358.29243032218073, 456.8031550931528, 493.4583084963061],&#xA;         [901.2468901063676, 731.716805616793, 570.2050359341547, ...,&#xA;          334.23748590136256, 433.893684216182, 479.71262597012355],&#xA;         ...,&#xA;         [-1690.9597396227766, -1719.596578218989, -1756.251731622142,&#xA;          ..., -348.46474623233917, -248.80854791751972,&#xA;          -521.4312513534605],&#xA;         [-1539.7572318347738, -1561.5212291678972, -1642.84985078114,&#xA;          ..., -371.37421710930994, -324.409801811521,&#xA;          -394.2836879862807],&#xA;         [-1335.8629410297408, -1397.7185123975598, -1535.1753376593797,&#xA;          ..., -397.7201086178229, -355.3375874954281,&#xA;          -338.15548433770346]]],&#xA;  mask=[[[False, False, False, ..., False, False, False],&#xA;         [False, False, False, ..., False, False, False],&#xA;         [False, False, False, ..., False, False, False],&#xA;         ...,&#xA;         [False, False, False, ..., False, False, False],&#xA;         [False, False, False, ..., False, False, False],&#xA;         [False, False, False, ..., False, False, False]]],&#xA;  fill_value=1e+20)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IHpA9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IHpA9.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;but it gives me negative values.&lt;/p&gt;&#xA;&lt;p&gt;How do I exactly convert geopotential height to pressure at surface?&lt;/p&gt;&#xA;" OwnerUserId="17926" LastEditorUserId="17926" LastEditDate="2021-10-16T15:22:03.077" LastActivityDate="2021-10-16T18:50:21.010" Title="How to calculate sea level pressure from geopotential height?" Tags="|meteorology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="22999" PostTypeId="1" CreationDate="2021-10-15T22:02:16.773" Score="1" ViewCount="112" Body="&lt;p&gt;I have heard in the radio in one discussion between an  executor and economist that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The world of a humans have technology with the ability to feed 200&#xA;billion of its kind but the existence of 2 billion of them like&#xA;children are hungry.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So I have asked here to know is this right and if possible I would like to know some tags for finding some academic papers or media posts about the above context.&lt;/p&gt;&#xA;" OwnerUserId="24676" LastEditorDisplayName="user20559" LastEditDate="2021-10-18T11:29:07.317" LastActivityDate="2021-10-18T11:29:07.317" Title="How many people could be fed in this world?" Tags="|agriculture|technology|" AnswerCount="1" CommentCount="4" ClosedDate="2021-10-17T13:38:57.070" ContentLicense="CC BY-SA 4.0" />
  <row Id="23000" PostTypeId="2" ParentId="22998" CreationDate="2021-10-16T15:35:25.900" Score="2" Body="&lt;p&gt;You should expect some negative values for &lt;span class=&quot;math-container&quot;&gt;$dp$&lt;/span&gt; as that's the pressure difference from 1000 hPa. Another thing that are doing wrong is not scaling your &lt;span class=&quot;math-container&quot;&gt;$dp$&lt;/span&gt; values to convert from pascals to hPa. The product of a density in kg/m&lt;sup&gt;3&lt;/sup&gt;, acceleration in m/s&lt;sup&gt;2&lt;/sup&gt;, and distance in meters is pressure in pascals. Divide by 100 to yield hPa.&lt;/p&gt;&#xA;&lt;p&gt;It also appears that you have a sign problem. If the 1000 hPa geopotential height is positive (above sea level), the pressure at sea level should be higher than 1000 hPa, The opposite applies if the 1000 hPa geopotential height is negative.&lt;/p&gt;&#xA;&lt;p&gt;From your first plot, it appears that the 1000 hPa geopotential height ranges from 125.2 meters below sea level (the deepest blue) to 274.8 meters above sea level (the deepest red). That 400 meter range means that is not quite correct to assume constant density, but it's close enough for a zeroth order approximation. The -125.2 meter geopotential height results in a sea level pressure of &lt;a href=&quot;https://www.wolframalpha.com/input/?i=1000%2B%28%28-85.2-%28234.8-154.8%29%2F2%29*%281.25%29*%289.80665%29%29%2F100&quot; rel=&quot;nofollow noreferrer&quot;&gt;984.7 hPa&lt;/a&gt; (assuming a constant density of &lt;span class=&quot;math-container&quot;&gt;$1.25\,\text{kg}/\text{m}^3$&lt;/span&gt; and a constant gravitational acceleration of &lt;span class=&quot;math-container&quot;&gt;$9.80665\,\text{m}/\text{s}^2$&lt;/span&gt;), while the +274.8 meter geopotential height results in a sea level pressure of &lt;a href=&quot;https://www.wolframalpha.com/input/?i=1000%2B%28234.8%2B%28234.8-154.8%29%2F2%29*%281.25%29*%289.80665%29%2F100&quot; rel=&quot;nofollow noreferrer&quot;&gt;1033.7 hPa&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2021-10-16T18:50:21.010" LastActivityDate="2021-10-16T18:50:21.010" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23001" PostTypeId="2" ParentId="22999" CreationDate="2021-10-16T17:03:05.703" Score="2" Body="&lt;p&gt;As mentioned in the comments, 200 billion people is an unrealistic world population. However, according to the FAO and the U.N. (e.g. &lt;a href=&quot;https://www.fao.org/sustainable-development-goals/goals/goal-2/en/&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;https://www.unep.org/news-and-stories/story/how-feed-10-billion-people&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;, &lt;a href=&quot;https://www.fao.org/3/x0262e/x0262e05.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;), current levels of food production are more than sufficient to feed today's world population (a similar claim is also included in the 2014 IPCC &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/02/WGIIAR5-Chap7_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;report&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;Many of the reports of the FAO suggest steps in the direction of not having the present contradictions such as the &lt;a href=&quot;https://www.nationalgeographic.com/environment/article/141013-food-waste-national-security-environment-science-ngfood&quot; rel=&quot;nofollow noreferrer&quot;&gt;huge amounts of food waste while millions of people are hungry&lt;/a&gt;, of keeping food production sustainable, etc. But it should be emphasized that the present levels of food production are already sufficient to feed the global population and that world hunger / undernourishment / food insecurity are not because of scarcity or inability to produce enough for all.&lt;/p&gt;&#xA;" OwnerUserId="24481" LastActivityDate="2021-10-16T17:03:05.703" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23003" PostTypeId="2" ParentId="22994" CreationDate="2021-10-17T03:06:54.307" Score="2" Body="&lt;p&gt;What you are seeing is the netadata about one grib message, specifically the 850 mb level (as that is what you specified). Based on my guess, it looks like it is a narrow boxed subset, not the corners like you want.&lt;/p&gt;&#xA;&lt;p&gt;Without knowing what dataset you are inquiring about, I can only guess. But from what I see, this is what I can tell.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The first column describes when the data was started.&lt;/li&gt;&#xA;&lt;li&gt;The second column describes when the model is valid.&lt;/li&gt;&#xA;&lt;li&gt;The third column describes, in shortened terms, the variable that the data represents (TMP=temperature).&lt;/li&gt;&#xA;&lt;li&gt;The fourth column describes the height that the variable is valid for (850 mb).&lt;/li&gt;&#xA;&lt;li&gt;The fifth column is either latitude or longitude.&lt;/li&gt;&#xA;&lt;li&gt;The sixth column is either longitude or latitude (the one that it wasn't in #5)&lt;/li&gt;&#xA;&lt;li&gt;The last column is the value at that gridpoint.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Generally, I use wgrib to just do a cursory glance at the metadata of a file. I usually use &lt;a href=&quot;https://github.com/jswhit/pygrib&quot; rel=&quot;nofollow noreferrer&quot;&gt;pygrib&lt;/a&gt; to look at the actual data.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-10-17T03:06:54.307" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23004" PostTypeId="1" AcceptedAnswerId="23012" CreationDate="2021-10-17T12:37:36.317" Score="7" ViewCount="241" Body="&lt;p&gt;Smartphones have incorporated many sensors and some of them can be helpful for a geologist in the field:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;They have GPS, so it is possible to register your route in a Google Maps map. I find this may be interesting in combination with image, video, audio or text registration.&lt;/li&gt;&#xA;&lt;li&gt;They have an orientation sensor, so it is possible to create a compass with a few lines of code. The doubt is whether someone is going to trust this kind of device instead of an expensive mechanical compass.&lt;/li&gt;&#xA;&lt;li&gt;Some devices measure color. I doubt this can be very useful (color &amp;quot;x4832789bjkfbjk&amp;quot; or whatever is the output).&lt;/li&gt;&#xA;&lt;li&gt;?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I am curious to maybe develop one in the future, or encourage a reader to program one.&lt;/p&gt;&#xA;&lt;p&gt;Ideas/feedbacks?&lt;/p&gt;&#xA;&lt;p&gt;How can the device help geologists in the field?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-10-19T12:07:06.810" LastActivityDate="2023-07-10T19:12:36.003" Title="How can smartphones help geologists in the field?" Tags="|geology|structural-geology|gis|cartography|technology|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23005" PostTypeId="2" ParentId="23004" CreationDate="2021-10-17T15:42:05.243" Score="3" Body="&lt;p&gt;Part of the answer lies in where the geologist will be working and if there will be coverage by cellular/mobile telephone networks.&lt;/p&gt;&#xA;&lt;p&gt;It is my experience that a number of geologists, particularly exploration geologists, may work in remote regions where there is are no cellular/mobile telephone networks - parts of Africa, central Asia, Australia, South America, Canada &amp;amp; Siberia. In such regions smartphones are of no use.&lt;/p&gt;&#xA;&lt;p&gt;Any emergency communication that may be required is either done via a satellite telephone or via radio, similar to citizens band radio, but better. Sometimes the geologist must drive to the nearest town that has a telephone or cellular/mobile telephone coverage.&lt;/p&gt;&#xA;&lt;p&gt;As for compasses, I know many geologists who would feel naked without their &lt;a href=&quot;https://en.wikipedia.org/wiki/Brunton_compass&quot; rel=&quot;nofollow noreferrer&quot;&gt;Brunton Compasses&lt;/a&gt;. Their tool kit would be incomplete without one.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-10-18T08:44:49.300" LastActivityDate="2021-10-18T08:44:49.300" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23007" PostTypeId="2" ParentId="22741" CreationDate="2021-10-19T03:15:07.827" Score="0" Body="&lt;p&gt;Yea,but by a mere infinitesimal amount. Earth as a rough sphere has a surface area of 196.9 million square miles  or 509 Trillion square meters, add atmospheres thickness 100 miles up it's 200 million of exposed to solar light, 3700 random objects with a area of 5-10 square meters is 37,000 meters square, barely 0.01 square miles, so 1/16 billionth of the Earth's light is blocked by orbiting stuff.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-10-19T03:15:07.827" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23008" PostTypeId="2" ParentId="22990" CreationDate="2021-10-19T03:38:45.523" Score="1" Body="&lt;p&gt;&lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/080271529X&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.amazon.com/Longitude-Genius-Greatest-Scientific-Problem/dp/080271529X&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I think you should read the book by Dava Sobell.  It will give you perspective and lead you to original source materials.  See:&lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/080271529X&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.amazon.com/Longitude-Genius-Greatest-Scientific-Problem/dp/080271529X&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24699" LastActivityDate="2021-10-19T03:38:45.523" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23009" PostTypeId="2" ParentId="22941" CreationDate="2021-10-19T03:56:23.323" Score="0" Body="&lt;p&gt;Take a look at the work of John Valley at the University of Wisconsin.  He has dated zircons from the Jack Hills in Australia.  Now, he is analyzing glassy inclusions in zircons.  The inclusions are unaltered siliceous magma that formed the crust of the early earth. The American Geophysical Union published a volume of papers you should see.  The book &amp;quot;The Early Earth&amp;quot; is at &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/book/10.1002/9781118860359&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://agupubs.onlinelibrary.wiley.com/doi/book/10.1002/9781118860359&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24699" LastEditorUserId="2470" LastEditDate="2021-10-19T09:27:26.460" LastActivityDate="2021-10-19T09:27:26.460" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23010" PostTypeId="2" ParentId="21252" CreationDate="2021-10-19T05:15:35.757" Score="1" Body="&lt;p&gt;CO2 follows temp, not the other way around. When temperatures decline, biological activity decreases and available biologically derived carbon also declines.  When temps increase and soil carbon outputs improve freely available carbon dioxide reintroduces into the biosphere. Biological absorption is more paramount, because as frozen tundra, non-fossilized plants such as peat and bogs proliferate in cooler climates.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-10-19T05:15:35.757" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23011" PostTypeId="2" ParentId="12637" CreationDate="2021-10-19T07:49:32.447" Score="-3" Body="&lt;p&gt;Unknown, namely because most scientists in &amp;quot;Earth science&amp;quot; related spectrum largely work in the public sector i.e. tax payer funded research (museums, smithsonian, various universities, USGS, etc) hense bias to human anthropological warming tends to be &amp;quot;Yay&amp;quot;. You don't receieve funding for a circumstance you don't take as inherently serious.&lt;/p&gt;&#xA;&lt;p&gt;Science, unlike religion, is not a belief system. Scientists, just like anyone else, are susceptible to error and BEING wrong about something they stringently vouch for.&lt;/p&gt;&#xA;&lt;p&gt;The earliest attempt to document a “consensus” on climate change was a old 2004 paper cited by Al Gore in his book, An Inconvenient Truth. (Gore attended natural science class at Harvard, but got D grade). The primary paper that ups the notion of “97% consensus” was written by John Cook and company and was &lt;a href=&quot;https://iopscience.iop.org/article/10.1088/1748-9326/8/2/024024&quot; rel=&quot;nofollow noreferrer&quot;&gt;published&lt;/a&gt; in 2013. As to how many of them are scientists, the list puts down Profession of science discipline as geology. I don't know.&lt;/p&gt;&#xA;&lt;p&gt;Consensus is a political/social concept i.e. Majority rules. Consensus is irrelevant in science as history has shown; scientific discovery and introductions did not enjoy relative endorsement by a majority of the community, in fact fought tooth and nail against it...but in the end fought against institutions and were proven right.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Galileo (Heliocentrism)&lt;/li&gt;&#xA;&lt;li&gt;Charles Darwin (Biologically derived inheritence/species propagation)&lt;/li&gt;&#xA;&lt;li&gt;Gregor Mendel (acquired characteristics)&lt;/li&gt;&#xA;&lt;li&gt;Einstein (Relativity, Early quantum mechanics&lt;/li&gt;&#xA;&lt;li&gt;Dan Shechtman (Nobel in physics in discovery of quasi-crystals)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-10-19T07:49:32.447" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23012" PostTypeId="2" ParentId="23004" CreationDate="2021-10-19T08:28:49.940" Score="3" Body="&lt;p&gt;I know a young geologist using his smartphone as a compass. When we were in the field doing structural measurements together, I would:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Record a waypoint using my hiking GPS&lt;/li&gt;&#xA;&lt;li&gt;Take the measurement with my compass&lt;/li&gt;&#xA;&lt;li&gt;Write it all down in my field notebook&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Given the time to take all the things out, and put them away afterwards, it was at least 2&lt;span class=&quot;math-container&quot;&gt;$-$&lt;/span&gt;3 minutes per measurement. And of course, I would have to wait until the evening to put all the data from my notebook into my computer by hand (which is source of error), and finally be able to plot it on a stereographic projection.&lt;/p&gt;&#xA;&lt;p&gt;He could do all of the above in 5 seconds with his smartphone, and visualize the results in real-time.&lt;/p&gt;&#xA;&lt;p&gt;I think he was following the article &amp;quot;Structural data collection with mobile devices: Accuracy, redundancy, and best practices&amp;quot; (&lt;a href=&quot;https://doi.org/10.1016/j.jsg.2017.07.011&quot; rel=&quot;nofollow noreferrer&quot;&gt;Allmendinger et al., 2017&lt;/a&gt;). The study found that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;With some modest precautions, Apple® iPhones can be successfully used&#xA;by structural geologists as data collection devices in the field.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;But still warned:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;As of today, the structural geologist will still want to take their&#xA;analog compass to the field with them and verify their phone&#xA;observations. Anyone contemplating data collection with any smart&#xA;phone needs to carry out extensive tests of the kind performed here to&#xA;verify that the data collected are reliable.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Another use I know of is photogrammetry (e.g., &lt;a href=&quot;https://doi.org/10.1130/GSATG506A.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Corradetti et al., 2021&lt;/a&gt;), but I am less familiar with this topic.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2021-10-19T08:28:49.940" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23013" PostTypeId="1" AcceptedAnswerId="23014" CreationDate="2021-10-19T10:59:06.740" Score="7" ViewCount="277" Body="&lt;p&gt;I'm working with time series of weather data (specifically, min/max daily temperatures and relative humidity) recorded from weather stations over an area of about 200,000 km&lt;sup&gt;2&lt;/sup&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I would be interested in spatially distributing said data, generating surfaces of weather info. This however should be done by also taking into account the diverse terrain and elevation of the region over which the weather stations are installed.&lt;/p&gt;&#xA;&lt;p&gt;A similar project that I found referenced this work:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Thornton &lt;em&gt;et al.&lt;/em&gt; (1997). Generating surfaces of daily meteorological variables over large regions of complex terrain. &lt;em&gt;Journal of Hydrology&lt;/em&gt;, 190 (3-4). &lt;a href=&quot;https://doi.org/10.1016/S0022-1694(96)03128-9&quot; rel=&quot;noreferrer&quot;&gt;https://doi.org/10.1016/S0022-1694(96)03128-9&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The paper presents indeed a way to generate exactly the surfaces I need. Since however my programming skills are very limited, what I would like to know is whether there already is a software, or software library (preferably free and open source), that implements the algorithm by Thornton &lt;em&gt;et al.&lt;/em&gt; or a similar one.&lt;/p&gt;&#xA;&lt;p&gt;I found the very promising Python library &lt;a href=&quot;https://github.com/openamundsen/openamundsen&quot; rel=&quot;noreferrer&quot;&gt;openamundsen&lt;/a&gt;, which seems to do exactly what I need, among many other things, but I would like to collect different possible options in order to compare them.&lt;/p&gt;&#xA;&lt;p&gt;Any help is greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="24704" LastEditorUserId="24481" LastEditDate="2021-10-19T11:28:25.397" LastActivityDate="2021-10-19T16:18:16.493" Title="Software for spatial interpolation of temperature and relative humidity data from weather stations" Tags="|meteorology|mapping|software|gis|weatherdata|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23014" PostTypeId="2" ParentId="23013" CreationDate="2021-10-19T16:18:16.493" Score="4" Body="&lt;p&gt;I am presently working on exactly this.&lt;/p&gt;&#xA;&lt;p&gt;I am using &lt;a href=&quot;https://climate.copernicus.eu/climate-reanalysis&quot; rel=&quot;nofollow noreferrer&quot;&gt;climate reanalysis&lt;/a&gt; data, to fill in the 'empties' since my climate stations are far away from each other. Or, sometime, I have N/A's in my series that I would like to fill-in or relate.&lt;/p&gt;&#xA;&lt;p&gt;From the &lt;strong&gt;Copernicus&lt;/strong&gt; site:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Climate reanalyses combine past observations with models to generate consistent time series of multiple climate variables. Reanalyses are among the most-used datasets in the geophysical sciences. They provide a comprehensive description of the observed climate as it has evolved during recent decades, on 3D grids at sub-daily intervals.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Note: While Copernicus is European, their products are global. And there are other providers of reanalyses, but Copernicus is in my opinion one of the most convenient due to:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;their documentation,&lt;/li&gt;&#xA;&lt;li&gt;the examples they provide,&lt;/li&gt;&#xA;&lt;li&gt;the relatively simple API's they developed (python) and documented.&lt;/li&gt;&#xA;&lt;li&gt;their tutorials to obtain data - which a non-programmer but someone technically savvy could learn to do&lt;/li&gt;&#xA;&lt;li&gt;their supercomputing abilities (say you need data for your grid, you launch the request and you go through the queue of requests, and tomorrow, you got an email with your csv file or the numeric output you requested)&lt;/li&gt;&#xA;&lt;li&gt;their live support (well, not live, but someone is answering nicely in a timely manner)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;There are several reanalysis products available, for example:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;ERA5&lt;/li&gt;&#xA;&lt;li&gt;ERA5-Land&lt;/li&gt;&#xA;&lt;li&gt;Arctic&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Each have their own time interval, spatial resolution; some exclude the oceans (ERA5-Land). I personally use ERA5-Land due to the fine spatial resolution and the time interval covered. Several variables are available depending on your needs.&lt;/p&gt;&#xA;&lt;p&gt;Note: there is other reanalysis product out there that could better fit your needs, or other solutions.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastActivityDate="2021-10-19T16:18:16.493" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23015" PostTypeId="1" AcceptedAnswerId="23016" CreationDate="2021-10-19T16:35:01.703" Score="6" ViewCount="125" Body="&lt;h2&gt;Some facts I have learnt&lt;/h2&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Global Warming Potential (GWP) was developed to allow comparisons of the global warming impacts of different gases. Specifically, it is a measure of how much energy the emissions of 1 ton of a gas will absorb over a given period of time, relative to the emissions of 1 [US] ton of carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;).&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;[...]&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Nitrous Oxide (N2O) has a GWP 265–298 times that of CO&lt;sub&gt;2&lt;/sub&gt; for a 100-year timescale.&lt;br&gt; — &lt;a href=&quot;https://www.epa.gov/ghgemissions/understanding-global-warming-potentials&quot; rel=&quot;nofollow noreferrer&quot;&gt;United States Environment Protection Agency&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;According to the UK Government's Department for Environment, Food &amp;amp; Rural Affairs (&lt;a href=&quot;https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2021&quot; rel=&quot;nofollow noreferrer&quot;&gt;DEFRA, 2021&lt;/a&gt;):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SzLRv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SzLRv.png&quot; alt=&quot;Table of greenhouse gasses released into the atmosphere per 1 kilowatt-hour of fuel used&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;With the average UK annual household gas usage being 12,000 kWh (&lt;a href=&quot;https://www.ukpower.co.uk/home_energy/average-household-gas-and-electricity-usage&quot; rel=&quot;nofollow noreferrer&quot;&gt;UK Power, n.d.&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;A heat pump that has a &lt;a href=&quot;https://www.sciencedirect.com/topics/engineering/coefficient-of-performance&quot; rel=&quot;nofollow noreferrer&quot;&gt;Coefficient of Performance (CoP)&lt;/a&gt; of three can create three kWh of heat from every one kWh of electricity. Therefore, compared to average gas usage, a heat pump with a CoP of three would use 4,000 kWh of electricity annually (&lt;a href=&quot;https://www.viessmann.co.uk/heating-advice/Do-heat-pumps-use-a-lot-of-electricity&quot; rel=&quot;nofollow noreferrer&quot;&gt;Viessmann, n.d.&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Z3pqf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Z3pqf.png&quot; alt=&quot;UK average figures table for household greenhouse gas emissions&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The UK Government is looking for everyone to install Heat Pumps for home heating and will be banning the installation of gas combi boilers.&lt;/p&gt;&#xA;&lt;p&gt;But, from my calculations, heat pumps could provide little benefit to the environment in comparison to gas central heating. Where is the major benefit I am missing?&lt;/p&gt;&#xA;&lt;h2&gt;References&lt;/h2&gt;&#xA;&lt;p&gt;DEFRA (2021) &lt;em&gt;UK Government GHG Conversion Factors for Company Reporting&lt;/em&gt; &lt;a href=&quot;https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2021&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.gov.uk/government/publications/greenhouse-gas-reporting-conversion-factors-2021&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;UK Power (n.d.) &lt;em&gt;Average gas and electric usage for UK households&lt;/em&gt; &lt;a href=&quot;https://www.ukpower.co.uk/home_energy/average-household-gas-and-electricity-usage&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ukpower.co.uk/home_energy/average-household-gas-and-electricity-usage&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Veissmann (n.d.) &lt;em&gt;Do heat pumps use a lot of electricity?&lt;/em&gt; &lt;a href=&quot;https://www.viessmann.co.uk/heating-advice/Do-heat-pumps-use-a-lot-of-electricity&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.viessmann.co.uk/heating-advice/Do-heat-pumps-use-a-lot-of-electricity&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21081" LastEditorUserId="2470" LastEditDate="2021-10-20T15:00:21.500" LastActivityDate="2021-10-20T15:00:21.500" Title="Would home heat pumps provide large benefits against climate change?" Tags="|climate-change|air-pollution|pollution|carbon|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23016" PostTypeId="2" ParentId="23015" CreationDate="2021-10-19T19:42:24.953" Score="6" Body="&lt;p&gt;&lt;strong&gt;The values on the DEFRA table with the column heading  &lt;span class=&quot;math-container&quot;&gt;$ kg\ \ce{N2O} $&lt;/span&gt; already include the global warming potential (GWP) factor of 298,&lt;/strong&gt; as indicated by a note on the column heading (looking at electricity):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/x6A9k.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/x6A9k.png&quot; alt=&quot;Note on &amp;quot;kg N2O&amp;quot; reads &amp;quot;kg CO2e of N2O per unit&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is pretty confusing and took me a while to track down, but I figured it out when I noticed that the value in the first column is simply the sum of the values in the next three columns, which only makes sense once you understand that those three values are already converted to equivalent &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; emissions (or &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2e}$&lt;/span&gt;).&lt;/p&gt;&#xA;&lt;p&gt;There are a couple other minor issues with your calculation:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;GWP is a factor per unit mass, so there's no need to convert to US tons.&lt;/li&gt;&#xA;&lt;li&gt;The &lt;code&gt;12,000 kWh&lt;/code&gt; figure is for &lt;em&gt;gas usage&lt;/em&gt;, or what's recorded at the meter. Since no furnace is 100% efficient, this means that the heating load (how much heat is actually added to the home) will be less. For years, natural gas furnaces had an efficiency of 80%, but newer models can reach closer to 98%. Let's assume it's 90% on average. This means the actual heating load is &lt;span class=&quot;math-container&quot;&gt;$12\,000 \times 0.9 = 10\,800\ \text{kWh}$&lt;/span&gt;, which makes the electricity needed to provide the same amount of heat &lt;span class=&quot;math-container&quot;&gt;$10\,800 \div 3 = 3\,600\ \text{kWh}$&lt;/span&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Here's how the final table should look:&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th&gt;Heating system&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Heating fuel (kWh)&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;&lt;span class=&quot;math-container&quot;&gt;$ kg\ \ce{CO2e}$&lt;/span&gt; per kWh&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Total &lt;span class=&quot;math-container&quot;&gt;$ kg\ \ce{CO2e}$&lt;/span&gt;&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Natural gas furnace (90%)&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;&lt;span class=&quot;math-container&quot;&gt;$12\,000$&lt;/span&gt;&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;&lt;span class=&quot;math-container&quot;&gt;$0.18316$&lt;/span&gt;&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;&lt;span class=&quot;math-container&quot;&gt;$1\,978$&lt;/span&gt;&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Heat pump (COP 3)&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;&lt;span class=&quot;math-container&quot;&gt;$3\,600$&lt;/span&gt;&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;&lt;span class=&quot;math-container&quot;&gt;$0.21233$&lt;/span&gt;&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;&lt;span class=&quot;math-container&quot;&gt;$764$&lt;/span&gt;&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;&#xA;&lt;p&gt;Finally, while the equivalent emissions factor for electricity is currently higher than that for natural gas, it's trending down, as indicated by this note in the spreadsheet:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In the 2019 GHG Conversion Factors, there was a 10% decrease in the UK Electricity CO2e factor compared to the previous year. In the 2020 update, the CO2e factor decreased (compared with 2019) again by 9%. In the 2021 update, the CO2e factor has again decreased by 9% (in comparison to the 2020 update). The above decreases are all due to a decrease in coal use in electricity generation and an increase in renewable generation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7741" LastEditorUserId="7741" LastEditDate="2021-10-20T14:31:24.367" LastActivityDate="2021-10-20T14:31:24.367" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23018" PostTypeId="2" ParentId="22941" CreationDate="2021-10-19T19:52:29.497" Score="0" Body="&lt;p&gt;The oldest radioactive dating is uranium lead quantities and zircon. Oceanic fossils and minerals give us a estimate of height of primitive oceans. And the oxide mineral contents of geologic strata give us estimate of how much carbon and oxygen were in our primitive atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-10-19T19:52:29.497" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23019" PostTypeId="1" CreationDate="2021-10-20T02:30:30.747" Score="2" ViewCount="65" Body="&lt;p&gt;I am curious what the modern accuracy for paleomagnetic azimuthal orientation measurements are. Let's say for a magnetite grain, is the orientation of the magnetic moment for a single crystal resolved down to the 1 degree? .01 degrees? or 0.00001 degree?&lt;/p&gt;&#xA;" OwnerUserId="23131" LastActivityDate="2021-10-29T05:48:03.780" Title="How accurate are paleomagnetic orientation measurements?" Tags="|geomagnetism|paleomagnetism|rock-magnetism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23020" PostTypeId="2" ParentId="14809" CreationDate="2021-10-20T11:15:55.200" Score="4" Body="&lt;p&gt;You can see this effect on the powerline above the railroad tracks in the picture you posted too, it doesn't look straight, even though it likely was in reality! The straight line between the sun and the moon is just even &lt;em&gt;more&lt;/em&gt; curved. Just like what you see at &lt;a href=&quot;http://chrisjones.id.au/MoonIllusion/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://chrisjones.id.au/MoonIllusion/&lt;/a&gt; , like the top answer already posted. If you accept that the curvature of the powerline on this picture is just an optical illusion/distortion introduced by the camera, then so is the sun-moon illumation!&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TqHHU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TqHHU.png&quot; alt=&quot;the picture curves straight lines&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The error in your diagram is that you assume a rectangular and linear (0, 1 or 2 point foreshortening) perspective. As you can see &lt;a href=&quot;https://youtu.be/Y2gTSjoEExc?t=190&quot; rel=&quot;nofollow noreferrer&quot;&gt;in this VSauce video&lt;/a&gt;, straight lines in our surroundings actually become curved lines from a single eye (or photocamera) perspective. After you've seen the VSauce video, you can check that this holds true for you too: if you rotate your head, you'll notice that the place where your wall and ceiling meet will curve when you're moving from side to side. Straight lines, when viewed from below from left to right cease to be straight! A 5-point curved perspective better captures the way straight lines appear to us.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/X9lKd.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/X9lKd.jpg&quot; alt=&quot;5 point perspective&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Note, by the way, that even from a &amp;quot;torch&amp;quot; perspective, as you insist, and without any optical illusion, we can get the moon shining &amp;quot;upward&amp;quot;. Consider the following overview picture: the moon (left object) is illuminated by the sun (right object) in exactly the way you expect. Now, however, consider that you are an observer (where the two red lines converge), in particular, that you are standing &lt;em&gt;below&lt;/em&gt; the sun and moon. As you know, if you stand below things, you cannot see what is on top -- and similarly, you can see more of what is on the bottom of that object. That is what's drawn in the dotted lines from the observer view: they tangentially hit the moon on the dark side on the bottom, and cannot observe the top of the moon. Just because we're below that object.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VaU9B.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VaU9B.png&quot; alt=&quot;Overview picture of moon and sun&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Thus, if you place yourself in the position of the observer, the objects will appear as if they have both rotated away from the horizon, because we can see &lt;strong&gt;both&lt;/strong&gt; bottoms of the objects!&lt;/p&gt;&#xA;&lt;p&gt;If you put the two effects together (one, the strange effects of panning from left to right to lines above us; and the effect of being located below the moon), we end up with the following effect, where it appears that the &amp;quot;moon&amp;quot; is facing upwards to the right in the first few frames when we're looking to the left, but once we zoom out you can see that the sun is actually level with the moon!&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EhVnt.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EhVnt.gif&quot; alt=&quot;sun-moon system&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The effect nearly disappears entirely once I add a line connecting the two bodies:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2DM0E.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2DM0E.gif&quot; alt=&quot;sun-moon system with added lines&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now the effect looks like it isn't even there anymore, because somehow our brains are able to make sense of the perspective. Note how in every single picture, the lines are all straight (so, no trickery with wide-angle or fish-eye lenses), but when we rotate from left to right, they seem to &amp;quot;change direction&amp;quot; from pointing northeast to northwest and back.&lt;/p&gt;&#xA;" OwnerUserId="12155" LastEditorUserId="12155" LastEditDate="2021-10-23T08:27:10.510" LastActivityDate="2021-10-23T08:27:10.510" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="23021" PostTypeId="1" CreationDate="2021-10-21T13:13:08.140" Score="3" ViewCount="51" Body="&lt;p&gt;A video of a recent tornado in Germany shows two points of glowing light appear at the end of the lifetime of a tornado, when the funnel is already almost entirely retracted. Here is &lt;a href=&quot;https://youtu.be/XaT6U0v6lqk?t=41&quot; rel=&quot;nofollow noreferrer&quot;&gt;a video link&lt;/a&gt;. The two glowing points appear at the tip of a church tower and in the cloud, at about the given timestamp.&lt;/p&gt;&#xA;&lt;p&gt;Is that an electric discharge, like a &lt;a href=&quot;https://en.wikipedia.org/wiki/St._Elmo%27s_fire&quot; rel=&quot;nofollow noreferrer&quot;&gt;St. Elmo's fire&lt;/a&gt;? Is that common with tornadoes?&lt;/p&gt;&#xA;" OwnerUserId="5396" LastActivityDate="2021-10-21T15:17:13.770" Title="Electric phenomenon when tornado funnel disappears?" Tags="|meteorology|lightning|tornado|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23024" PostTypeId="1" CreationDate="2021-10-21T18:05:25.893" Score="4" ViewCount="43" Body="&lt;p&gt;In images of Jezero crater on Mars, it looks like the delta fan is higher than the surrounding crater floor.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/39umL.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/39umL.jpg&quot; alt=&quot;https://www.nasa.gov/image-feature/traversing-mars-jezero-crater&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This indeed seems to be the case with closer-up images from the Perseverance rover taken from the edge of the delta.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UatKj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UatKj.jpg&quot; alt=&quot;https://www.jpl.nasa.gov/news/nasas-perseverance-sheds-more-light-on-jezero-craters-watery-past&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Intuitively, I would guess that a river flowing would dig a kind of trench in the ground where it flows, so the ancient river bed would be lower than its surroundings. So how did the delta end up higher than its surroundings?&lt;/p&gt;&#xA;&lt;p&gt;My hypothesis is that sediments were deposited, and erosion wore off the rocks around the delta, but somehow, the sediments from the delta were harder and didn't wear off as fast. Is this indeed the case, or is some other mechanism at play?&lt;/p&gt;&#xA;" OwnerUserId="18434" LastActivityDate="2021-10-21T18:05:25.893" Title="Why is the delta part of Jezero crater higher than the surroundings?" Tags="|sedimentology|rivers|erosion|mars|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23025" PostTypeId="1" CreationDate="2021-10-21T19:10:08.663" Score="1" ViewCount="36" Body="&lt;p&gt;I am trying to understand the benefits of AgTech for different crops, and particularly IoT-based solutions like soil sensors (humidity, temperature, NPK). What are the crops that are benefitting the most today from this technology?&lt;/p&gt;&#xA;&lt;p&gt;I would assume that it would be more beneficial for crops with high yield per Hectare, e.g. bananas would benefit more than corn. Is that the case?&lt;/p&gt;&#xA;" OwnerUserId="24710" LastActivityDate="2021-10-21T19:10:08.663" Title="What crops benefit the most from AgTech and particularly soil monitoring?" Tags="|agriculture|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23026" PostTypeId="1" AcceptedAnswerId="24036" CreationDate="2021-10-22T13:37:32.840" Score="7" ViewCount="198" Body="&lt;p&gt;I have been following the last events of Cumbre Vieja eruption since it started last month. Trying to grasp some basic knowledge of volcanology I have seen the eruption is classified as VEI-3 in the English Wikipedia and VEI-2 in the Spanish Wikipedia. According to the ejected volume it makes sense to say it is a VEI-3, but the experts on public television in Spain are not being that focused on the ejected volume but the type of eruption, which is Strombolian, so a VEI-2 for that case.&lt;/p&gt;&#xA;&lt;p&gt;Here you can see the difference:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Volcanic_Explosivity_Index&quot; rel=&quot;noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Volcanic_Explosivity_Index&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://es.wikipedia.org/wiki/%C3%8Dndice_de_explosividad_volc%C3%A1nica&quot; rel=&quot;noreferrer&quot;&gt;https://es.wikipedia.org/wiki/%C3%8Dndice_de_explosividad_volc%C3%A1nica&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Which is the real category of the current Cumbre Vieja eruption?&lt;/p&gt;&#xA;" OwnerUserId="24511" LastEditorUserId="2470" LastEditDate="2021-10-22T15:40:27.237" LastActivityDate="2022-07-17T16:40:39.220" Title="Volcanic Explosivity Index of Cumbre Vieja eruption" Tags="|geology|volcanology|natural-disasters|volcanic-eruption|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23027" PostTypeId="2" ParentId="22390" CreationDate="2021-10-22T15:29:39.007" Score="2" Body="&lt;p&gt;For simple calculation, use this: &lt;a href=&quot;https://www.calculatoratoz.com/en/optimum-number-of-rain-gauge-stations-calculator/Calc-5418&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.calculatoratoz.com/en/optimum-number-of-rain-gauge-stations-calculator/Calc-5418&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;You need to know the CV and degree of error (example: 10%).&lt;/p&gt;&#xA;&lt;p&gt;CV can be calculated from average and stdev of monthly rainfall in certain area. The equation is CV = 100*stdev/avg.&lt;/p&gt;&#xA;&lt;p&gt;Then number of optimum rain gauge will be N = (CV/error)^2.&lt;/p&gt;&#xA;&lt;p&gt;If you have more data (watershed, lands, or slope and elevation), you can also add this data and make different scenario (flat, mountain, forest&lt;/p&gt;&#xA;" OwnerUserId="24719" LastActivityDate="2021-10-22T15:29:39.007" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23028" PostTypeId="2" ParentId="22544" CreationDate="2021-10-22T15:46:20.950" Score="1" Body="&lt;p&gt;I think Standardized Precipitation Index (SPI) is good fit with your objective. The SPI value is spanning from -3 to +3, positive SPI values indicate greater than median precipitation (Wet) and negative values indicate less than median precipitation (Dry).&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;You can read the official guideline from WMO here: &lt;a href=&quot;http://www.wamis.org/agm/pubs/SPI/WMO_1090_EN.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.wamis.org/agm/pubs/SPI/WMO_1090_EN.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;To calculate SPI using satellite precipitation estimates, you can follow a training from NASA: &lt;a href=&quot;https://appliedsciences.nasa.gov/join-mission/training/english/arset-applications-gpm-imerg-reanalysis-assessing-extreme-dry-and-wet&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://appliedsciences.nasa.gov/join-mission/training/english/arset-applications-gpm-imerg-reanalysis-assessing-extreme-dry-and-wet&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;You can check this website &lt;a href=&quot;https://livingatlas.arcgis.com/droughtaware/drought/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://livingatlas.arcgis.com/droughtaware/drought/index.html&lt;/a&gt; on how SPI used to monitor drought.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="24719" LastActivityDate="2021-10-22T15:46:20.950" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23029" PostTypeId="2" ParentId="9857" CreationDate="2021-10-22T20:52:19.330" Score="1" Body="&lt;p&gt;First Venus has a very thick carbon dioxide atmosphere that traps heat. Wile mars also has a carbon dioxide atmosphere but unlike Venus it is very thin and mars is much further from the sun and there for can't really trap much heat.&lt;/p&gt;&#xA;" OwnerUserId="24721" LastActivityDate="2021-10-22T20:52:19.330" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23031" PostTypeId="1" AcceptedAnswerId="23038" CreationDate="2021-10-23T19:38:50.430" Score="4" ViewCount="130" Body="&lt;p&gt;I'm new to numerical modeling and trying to figure out how things work inside business codes.&lt;/p&gt;&#xA;&lt;p&gt;Consider a 1D domain divided into small cells of width dx and at the East and West a Neumann conditions boundary is affected (zero flow in the East and constant in the West). In the center, we have an upward outgoing flow. Here is an illustration image:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/X9uQ4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;problem illustration image&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The PDE governing this problem is given by the following:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/u9F5x.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;PDE governing the problem and BC conditions&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Questions&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The model is in 1D and the flow w is done along the fictitious axis y. How do we define it as a boundary condition in our model?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Are the defined boundary conditions calculated independently of the PDEP or should they be incorporated into the discrete form of the EDP as below (example with q2)?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VERN4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;BC at the Western coin&lt;/a&gt;&lt;/p&gt;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;I also question the correctness of the formulation of the condition on qa. Indeed, it is an outgoing flow towards the outside (thus according to the fictitious axis y). Is my way of writing it correct?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Thank you in advance!&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;EDIT: Pseudo-code&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;For all points contained in my domain except the well and boundary points:&#xA;    Apply (1) S * du/dt = T * d2u/dx2 + w&#xA;&#xA;At my well level (Neumann boundary condition)&#xA;    Apply (2) S * du/dt = T * d2u/dx2 + q&#xA;&#xA;At my boundary points (Left and rigth) -&amp;gt; Neumann condition&#xA;    q = Tdu/dx -&amp;gt; discretize and replace it in (3)&#xA;    (3) S * du/dt = T * d2u/dx2&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Is it right?&lt;/p&gt;&#xA;" OwnerUserId="24724" LastEditorUserId="24724" LastEditDate="2021-10-24T13:02:11.817" LastActivityDate="2021-10-25T13:48:22.193" Title="How are boundary conditions considered in PDEs?" Tags="|hydrology|numerical-modelling|hydrogeology|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23032" PostTypeId="2" ParentId="16988" CreationDate="2021-10-24T04:34:33.643" Score="2" Body="&lt;p&gt;I don't know if anyone is still interested in this question, but I am doing research on Uluru (a.k.a Ayers Rock), Australia, and the Mitten Ridge Sinkhole in Sedona, AZ (A very interesting combination of locations.).&lt;/p&gt;&#xA;&lt;p&gt;I have a photo just outside the sinkhole showing the sidewall of the Supai Sandstone. The sandstone is pitted just like honey-comb tafoni. Uluru has the caves everyone is familiar with around much of its base and some armchairs and other gnamma structures from its base to its peak, and a few tafoni that Twidale identifies on its sides. Uluru also has a coat of hematite completely covering it, 2-3 cm thick. Everyone wants to produce hematite from rust or a biogenic source, but the only way I can prove the formation of that much hematite, that thick, is by a great deal of heat, 800-1000 °C. It is done with terracotta clay in ceramics class regularly.&lt;/p&gt;&#xA;&lt;p&gt;The Mitten Ridge sinkhole was formed by hot gas from the mantle, hot enough to melt garnet, 1950 °C. The ceiling of the sinkhole is covered with tiny garnet crystals that could only have formed in cooling gas. The sinkhole is as far as the gas could melt its way through the strata moving up, maybe 1.5 km height, and it melted its way out into the air, and the tafoni in the sandstone is part of that pathway.&lt;/p&gt;&#xA;&lt;p&gt;So tafoni are holes melted in the rock when a great heating event happened. I would be glad to post several photos if anyone is interested and can tell me how. Otherwise the papers will go to journals in the next couple of weeks and you can see them there eventually. I will also be glad to correspond with anyone interested on this topic since this only scratches the very surface.&lt;/p&gt;&#xA;" OwnerUserId="24726" LastEditorUserId="2470" LastEditDate="2021-10-24T07:09:39.413" LastActivityDate="2021-10-24T07:09:39.413" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23034" PostTypeId="2" ParentId="14809" CreationDate="2021-10-25T07:11:19.670" Score="1" Body="&lt;p&gt;Here is what you do. Look at the moon. See which way the sunlit face of the moon is pointing, not in a picture but in a real-life view of the moon. Using your own perception, trace a line INCREMENTALLY through space that goes out in the direction &amp;quot;pointed to&amp;quot; by the lit side is pointing. Keep tracing that line until your line hits an object bright enough to light the moon OR until the line extends past the horizon. This process ill eventually lead you across the sky to the sun or in the direction of the sun at the horizon. Every. Single. Time.&lt;/p&gt;&#xA;&lt;p&gt;If you find otherwise, then you have an insufficient sense of three-dimensional direction and that requires either some kind of skills therapy or else just acceptance that you can't accurately imagine 3-D line tracing in the real world.&lt;/p&gt;&#xA;" OwnerUserId="7800" LastActivityDate="2021-10-25T07:11:19.670" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23035" PostTypeId="2" ParentId="20413" CreationDate="2021-10-25T08:57:31.240" Score="2" Body="&lt;p&gt;There's easier ways to mitigate toxic waste, Since most is often metal, converting it into stable oxides and proper landfilling mitigates most of the danger.&lt;/p&gt;&#xA;&lt;p&gt;Incineration at temperatures above 2800 degrees celsius will totally obliterate most wastes, this is How US &lt;a href=&quot;https://www.cdc.gov/nceh/demil/incineration.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;disposed&lt;/a&gt; of it's chemical warfare stockpile.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-10-25T08:57:31.240" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23036" PostTypeId="2" ParentId="9857" CreationDate="2021-10-25T09:02:29.777" Score="-2" Body="&lt;p&gt;CO2 does NOT control Earth's Climate, it plays a role, but so do other factors., in it's long geologic and shorter term histories. It played a role when CO2 was 10x that of present. Even so we had an Ice Age during the Ordivician (4,400 ppm). Jurassic cooling period (1,700 ppm)&#xA;The biggest influencer is the Sun. magnetic anomolies, sunspots, milankovitch cycles. Earth's orbit and axial tilt variation that permit More or less solar absorption.&lt;/p&gt;&#xA;&lt;p&gt;For the last 800,000 years, Earth's ambient CO2 NEVER went up above 280 ppm average. In the last 10,000 years, we've had 20 major warming and cooling events and ambient co2 remained fairly constant.....&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SHGgq.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SHGgq.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-10-25T09:02:29.777" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23038" PostTypeId="2" ParentId="23031" CreationDate="2021-10-25T13:48:22.193" Score="6" Body="&lt;p&gt;In any solution to a PDE, whether analytical or numerical, you will always need as many BCs as the number of derivative steps. For examples:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$dY/dt = k Y$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;needs one BC while&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\partial Y/\partial t = k \nabla^2 Y$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;needs three BCs. The second case is germane to your problem. You will need one BC on time &lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt; because one derivative is on time. You will need two &lt;em&gt;independent&lt;/em&gt; BCs on position because two derivatives are applied on position.&lt;/p&gt;&#xA;&lt;p&gt;We set BCs to make an otherwise general equation apply specifically to the physical system at hand. For heat transfer problems, viable conditions can include the following:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Time Domain&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;temperature at a given time&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;Spatial Domain&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;temperature at a given location&lt;/li&gt;&#xA;&lt;li&gt;heat flux at a given location&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;In regard to the spatial domain in a 1-D flow, one cannot set a heat flux BC at one point and set a heat flux BC at a second location. The two BCs are not independent. They are tied together by an energy balance on the overall system or across any spatial extent in the system.&lt;/p&gt;&#xA;&lt;p&gt;Now, specifically to your questions.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The system as illustrated is being modeled in a way that is equivalent to a 1-D fin. The heat flow &lt;span class=&quot;math-container&quot;&gt;$w$&lt;/span&gt; into the component is &amp;quot;lumped&amp;quot;. The temperature gradient in the component along its axis is ignored. You could easily have one cell along that direction and simplify the analysis. You have no BCs on that direction. Your alternative is to switch to a 2-D model to include the heat flow in the component along the &lt;span class=&quot;math-container&quot;&gt;$y$&lt;/span&gt; direction. The &amp;quot;topmost&amp;quot; cell takes &lt;span class=&quot;math-container&quot;&gt;$w$&lt;/span&gt; in and distributes it along &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$y$&lt;/span&gt;. The bottom-most cell takes heat from the topmost cell and distributes it along &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; (presuming the bottom is insulated).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The BCs are defined independently of the equations. In analytical evaluations, they are used to obtain the constants in the general integrations steps to the partial differential equation. In the numerical evaluations, they are used to initialize the computational routines or to pass solutions from one cell to another properly.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;We apply a BC on heat flow after the first spatial integration. We apply a spatial BC on temperature after the second spatial integration. We apply a temporal BC on temperature after the integration on time. You seem to be trying to incorporate the BCs directly into the general equation.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="13534" LastActivityDate="2021-10-25T13:48:22.193" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23039" PostTypeId="1" CreationDate="2021-10-25T14:30:33.493" Score="1" ViewCount="145" Body="&lt;p&gt;Five weeks ago my dad and I collected geodes near Bedford, Indiana, from private property with the full permission of the owner. While cutting the rocks one produced an unexpected result - oil poured out. I am in search of more information, but am new to this forum and unable to respond to another post due to my status.&lt;/p&gt;&#xA;&lt;p&gt;Insights appreciated. I have the example and I have photos of the experience immediately after it happened.&lt;/p&gt;&#xA;" OwnerUserId="24735" LastEditorDisplayName="user20559" LastEditDate="2021-10-27T08:18:44.733" LastActivityDate="2021-10-27T08:18:44.733" Title="Oil FIlled Geode" Tags="|geology|geode|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23040" PostTypeId="1" AcceptedAnswerId="23042" CreationDate="2021-10-26T16:44:24.057" Score="5" ViewCount="125" Body="&lt;p&gt;I was looking through the Weatherbug atmospheric pressure map around 8:30 am ET on Oct 26 2021, and noticed this chain of small high pressure blobs along the west coast of South America. It was also present around a few days prior, around 8 am ET on Oct 23 2021.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qMslj.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qMslj.jpg&quot; alt=&quot;A screenshot of an atmospheric pressure map of South America. There is a chain of eight small elliptical high pressure blobs along the west coast, roughly from Medellín in Colombia to La Paz in Bolivia.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I looked up the geography and major winds in the region and noticed&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;This is a region with mountains nearly along the coast&lt;/li&gt;&#xA;&lt;li&gt;There are northbound trade winds that roughly hug the coast&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;I then looked for a similar effect in other places with similar conditions and found this other high pressure chain along the southwest edge of Indonesia (screenshot from around 12 pm ET on Oct 26 2021):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FsKkE.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FsKkE.jpg&quot; alt=&quot;Six small blobs of high pressure extend across the southwest side of Indonesia, roughly from Padang in West Sumatra to Bali. This high pressure chain, compared to the South American one, has a lower maximum pressure, and more extensive low pressure regions between the blobs.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;There's a coast-hugging wind along this region (this one eastbound), and as far as I can tell the mountains here are lower than the ones in South America. I've noticed the high pressure blobs seem smaller and have a lower maximum pressure, though this may be due to it being night there when I checked.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;With all that background information, my questions are:&lt;/strong&gt; what, physically, causes this effect? Are these high-pressure chains semi-permanent, and if so, do the individual blobs tend to stay in the same place or shift around a bit?&lt;/p&gt;&#xA;&lt;p&gt;My background's in physics rather than meteorology so I'd love an answer that describes the physical phenomena or &amp;quot;follows the wind&amp;quot; as it encounters mountains and valleys. Bonus points for descriptions of how e.g. mountain spacing, mountain height, wind speed, etc may affect blob spacing and pressure magnitude.&lt;/p&gt;&#xA;" OwnerUserId="22772" LastActivityDate="2021-10-27T13:34:52.690" Title="What causes these periodic high-pressure blobs along the west coast of South America?" Tags="|meteorology|atmosphere|wind|barometric-pressure|mesoscale-meteorology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23042" PostTypeId="2" ParentId="23040" CreationDate="2021-10-27T13:34:52.690" Score="4" Body="&lt;p&gt;It's really not clear from their website what data source those maps are showing.  They could be derived purely from surface observations, purely from model output, some atmospheric analysis combination of the two, or something else.&lt;/p&gt;&#xA;&lt;p&gt;When I see such neat bullseyes like that, it's normally a warning sign that someone is trying to do too much with a sparse dataset by interpolating low numbers of data points over large distances.  I looked into quite a few of the blobs on your maps and they were all located in remote, sparsely populated regions such as mountains, national parks or extensive forests, often with an airfield or research station nearby where there could be an isolated weather station.  There are similar oddities in their wind speed maps, which mainly show blobs centered on towns and cities where weather stations are likely to be located:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Xm1Kp.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Xm1Kp.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Note that over the US the wind speed map is broadly in line with the ECMWF analysis, albeit with lots of artificial blobbiness because of whatever sampling and interpolating they're doing.&lt;/p&gt;&#xA;&lt;p&gt;I suspect that the surface pressure maps are made even worse because they're &lt;em&gt;surface&lt;/em&gt; pressure rather than &lt;em&gt;sea level&lt;/em&gt; pressure, so the sparse samples can reflect altitude more than transient weather.  That would lead to the major features that you've highlighted being persistent in time.&lt;/p&gt;&#xA;&lt;p&gt;The bottom line is that I think the features that you're seeing are artifacts of a bad&#xA;methodology rather than a physical phenomenon.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2021-10-27T13:34:52.690" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23045" PostTypeId="1" CreationDate="2021-10-27T17:06:04.663" Score="1" ViewCount="28" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Matterhorn#/media/File:On_the_summit.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Matterhorn#/media/File:On_the_summit.jpg&lt;/a&gt; shows a climber on top of Matterhorn.It really looks like the area is quite small maybe 2 m^2. What is the typical area of prominent peaks?&lt;/p&gt;&#xA;&lt;p&gt;I realize that the definition of what is the &amp;quot;peak&amp;quot;, is somewhat arbitrary, but one definition would be the zone around where the slope flattens out, and if you go further you will always go down.&lt;/p&gt;&#xA;" OwnerUserId="601" LastActivityDate="2021-10-27T17:06:04.663" Title="What is the area of prominient peaks" Tags="|geography|mountains|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23047" PostTypeId="1" CreationDate="2021-10-27T21:38:05.557" Score="5" ViewCount="1164" Body="&lt;p&gt;Currently i am dealing with a bunch of coordinates (epsg:4326 =&amp;gt; lat/lon) and their corresponding value (temperature). The goal is to write these coordinates and their values into a simple netcdf file and display it in e.g. QGIS (So you will have a colored square for each pixel/coordinate)&lt;/p&gt;&#xA;&lt;p&gt;Currently the data is in scattered format, thats why its first interpolated.&lt;/p&gt;&#xA;&lt;p&gt;After interpolation i tried to write the data (raster format) into a netcdf file, but thats failing:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import numpy as np&#xA;from scipy.interpolate import griddata&#xA;import xarray as xr&#xA;import pandas as pd&#xA;import rioxarray&#xA;import netCDF4 as nc4&#xA;&#xA;&#xA;lat = [50.1, 50.2, 50.3, 50.4, 50.5, 62]&#xA;lon = [8.1, 8.2, 8.3, 8.4, 8.5, 12]&#xA;temp = [1,2,3,4,5,6]&#xA;&#xA;# prepare a grid for interpolation&#xA;xi = np.arange(6.0, 14.0, 0.001)&#xA;yi = np.arange(48.0, 64.0, 0.001)&#xA;xi, yi = np.meshgrid(xi, yi)&#xA;# As you can see the grid is slightly bigger then the used coordinates&#xA;&#xA;# interpolate&#xA;zi = griddata((lon, lat), temp, (xi, yi), method='linear')&#xA;&#xA;# time to write this into a netcdf file&#xA;ds = nc4.Dataset('test.nc', 'w', format='NETCDF3_CLASSIC')&#xA;&#xA;dim_time = ds.createDimension('time', 0)&#xA;dim_lat = ds.createDimension('lat', len(yi))&#xA;dim_lon = ds.createDimension('lon', len(xi))&#xA;&#xA;# is this correct or how should i set CRS to epsg:4326 ?&#xA;crs = ds.createVariable('WGS84', 'c')&#xA;crs.spatial_ref = &amp;quot;&amp;quot;&amp;quot;GEOGCS[&amp;quot;WGS 84&amp;quot;,DATUM[&amp;quot;WGS_1984&amp;quot;,SPHEROID[&amp;quot;WGS 84&amp;quot;,6378137,298.257223563,AUTHORITY[&amp;quot;EPSG&amp;quot;,&amp;quot;7030&amp;quot;]],AUTHORITY[&amp;quot;EPSG&amp;quot;,&amp;quot;6326&amp;quot;]],PRIMEM[&amp;quot;Greenwich&amp;quot;,0,AUTHORITY[&amp;quot;EPSG&amp;quot;,&amp;quot;8901&amp;quot;]],UNIT[&amp;quot;degree&amp;quot;,0.01745329251994328,AUTHORITY[&amp;quot;EPSG&amp;quot;,&amp;quot;9122&amp;quot;]],AUTHORITY[&amp;quot;EPSG&amp;quot;,&amp;quot;4326&amp;quot;]]&amp;quot;&amp;quot;&amp;quot;&#xA;&#xA;time = ds.createVariable('time', 'f4', 'time')&#xA;&#xA;latitude = ds.createVariable('lat', 'f4', 'lat')&#xA;latitude.units = 'degrees north'&#xA;&#xA;longitude = ds.createVariable('lon', 'f4', 'lon')&#xA;longitude.units = 'degrees east'&#xA;&#xA;value = ds.createVariable('temperature', 'f4', ('time', 'lat', 'lon',))&#xA;&#xA;# fill with values&#xA;latitude[:] = lat # =&amp;gt; ERROR: ValueError: shape mismatch: objects cannot be broadcast to a single shape&#xA;longitude[:] = lon&#xA;value[0,:,:] = zi&#xA;value.grid_mapping = 'WGS84'&#xA;&#xA;ds.close()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;When i try to write to e.g. latitude variable it throws:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;ValueError: shape mismatch: objects cannot be broadcast to a single shape&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;I debugged throw the code but wasnt able to find the error, any experts around?&lt;/p&gt;&#xA;&lt;p&gt;Cheers!&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE #1:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I adjusted your source code to work with coordinates in epsg:3857 format (it is plotted correctly in matplotlib but invisible in QGIS):&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import numpy as np&#xA;from scipy.interpolate import griddata&#xA;import xarray as xr&#xA;import pandas as pd&#xA;import rioxarray&#xA;import netCDF4 as nc4&#xA;import matplotlib.pyplot as plt&#xA;from shapely.geometry import Point&#xA;import geopandas as gpd&#xA;&#xA;# --- Input data....&#xA;lat = [50.1, 50.2, 50.3, 50.4, 50.5, 62]&#xA;lon = [ 8.1,  8.2,  8.3,  8.4,  8.5, 12]&#xA;temp = [1  ,  2  ,  3  ,  4  ,  5  ,  6]&#xA;&#xA;# Put into pandas Dataframe&#xA;df = pd.DataFrame(&#xA;    {&#xA;        'latitude': lat,&#xA;        'longitude': lon,&#xA;        'temp': temp&#xA;    }&#xA;)&#xA;&#xA;# Prepare geometry&#xA;pointShp = [Point(x, y) for x, y in zip(df.longitude, df.latitude)]&#xA;pointGpd = gpd.GeoDataFrame(df, geometry=pointShp, crs='EPSG:4326')&#xA;&#xA;# Reproject&#xA;point3857 = pointGpd.to_crs('EPSG:3857')&#xA;point3857['x'] = point3857.apply(lambda x: x.geometry.centroid.x, axis=1)&#xA;point3857['y'] = point3857.apply(lambda x: x.geometry.centroid.y, axis=1)&#xA;df = point3857[['x','y','temp']]&#xA;lon = list(df['x'])&#xA;lat = list(df['y'])&#xA;temp = list(df['temp'])&#xA;&#xA;# Proceed with your source code&#xA;# --- Project input data on a regular grid&#xA;xi = np.arange(min(lon), max(lon), 1000)&#xA;yi = np.arange(min(lat), max(lat), 1000)&#xA;xi, yi = np.meshgrid(xi, yi)&#xA;zi = np.zeros_like(xi,dtype=np.float32) * -999&#xA;# zi = griddata((lon, lat), temp, (xi, yi), method='linear')&#xA;for i in range(len(temp)):&#xA;    idx = np.argmin( np.sqrt( (xi-lon[i])**2 + (yi-lat[i])**2) )&#xA;    zi[np.unravel_index(idx, xi.shape)] = temp[i]&#xA;&#xA;# Replace -0 with nan value (so i have invisible pixels instead of black background)&#xA;np.place(zi, zi == -0, None)&#xA;&#xA;# --- Check... =&amp;gt; LOOKS GOOD&#xA;plt.figure(figsize=(15,7))&#xA;plt.subplot(1,2,1)&#xA;plt.scatter(lon, lat, temp, temp)&#xA;plt.subplot(1,2,2)&#xA;plt.pcolor(xi, yi, np.where(np.isnan(zi),0,zi))&#xA;plt.show()&#xA;&#xA;# --- Open NetCDF file to write on&#xA;with nc4.Dataset('test.nc', 'w' , format='NETCDF3_CLASSIC') as ds:&#xA;    # --- Initialize the dimensions of the dataset&#xA;    dim_time = ds.createDimension('time', 0)&#xA;    dim_lat = ds.createDimension('lat', yi.shape[0])&#xA;    dim_lon = ds.createDimension('lon', xi.shape[1])&#xA;&#xA;    # --- Create the corresponding variables for the dimensions&#xA;    time = ds.createVariable('time', np.float32, 'time')&#xA;    latitude = ds.createVariable('lat', np.float32, 'lat')&#xA;    latitude.units = ['degrees north']&#xA;    latitude.axis  = ['Y']&#xA;    latitude.standard_name = ['latitude']&#xA;    longitude = ds.createVariable('lon', np.float32, 'lon')&#xA;    longitude.units = ['degrees east']&#xA;    longitude.axis = ['X']&#xA;    longitude.standard_name = ['longitude']&#xA;    &#xA;    # --- Fill with 1D (!) arrays of xi/yi, as the meshgrid returns 2D arrays...&#xA;    time[:] = 0&#xA;    latitude[:] = yi[:,0]&#xA;    longitude[:] = xi[0,:]&#xA;    &#xA;    # --- Create a coordinate reference system&#xA;    crs = ds.createVariable('WGS84', 'c')&#xA;    crs.spatial_ref = &amp;quot;&amp;quot;&amp;quot;GEOGCS[&amp;quot;WGS 84&amp;quot;,DATUM[&amp;quot;WGS_1984&amp;quot;,SPHEROID[&amp;quot;WGS 84&amp;quot;,6378137,298.257223563,AUTHORITY[&amp;quot;EPSG&amp;quot;,&amp;quot;7030&amp;quot;]],AUTHORITY[&amp;quot;EPSG&amp;quot;,&amp;quot;6326&amp;quot;]],PRIMEM[&amp;quot;Greenwich&amp;quot;,0,AUTHORITY[&amp;quot;EPSG&amp;quot;,&amp;quot;8901&amp;quot;]],UNIT[&amp;quot;degree&amp;quot;,0.01745329251994328,AUTHORITY[&amp;quot;EPSG&amp;quot;,&amp;quot;9122&amp;quot;]],AUTHORITY[&amp;quot;EPSG&amp;quot;,&amp;quot;4326&amp;quot;]]&amp;quot;&amp;quot;&amp;quot;    &#xA;&#xA;    # --- Ready the Temperature data field&#xA;    value = ds.createVariable('temperature', np.float32, ('time','lat','lon'))&#xA;    &#xA;    value.grid_mapping = 'WGS84' # the crs variable name&#xA;    value.grid_mapping_name = 'latitude_longitude'&#xA;    &#xA;    # --- Fill with values&#xA;    value[0,:,:] = zi&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Do i have to make any changes to netcdf variables in netcdf? (like units or axis?)&lt;/p&gt;&#xA;&lt;p&gt;Can i keep crs.spatial_ref / value.grid_mapping / value.grid_mapping_name ?&lt;/p&gt;&#xA;&lt;p&gt;Cheers!&lt;/p&gt;&#xA;" OwnerUserId="24748" LastEditorUserId="24748" LastEditDate="2021-10-28T12:20:03.820" LastActivityDate="2021-10-28T15:40:46.260" Title="Python - How to write interpolated raster to netcdf file" Tags="|geology|temperature|python|netcdf|interpolation|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23048" PostTypeId="1" CreationDate="2021-10-27T22:42:23.040" Score="6" ViewCount="67" Body="&lt;p&gt;I read in the latest IPCC report that felling trees growing in Northern areas lays bare snow cover that, since it's white, reflects sun rays so it's kinda good (or at least, has a substantial positive aspect about it). However, I may have misinterpreted that part, and I generally prefer natural environments left untouched. Is cutting down boreal forest good or bad for our climate (I mean it's obviously bad for the ecosystems)? Generally, I assume, you don't burn that limber but use as building materials etc., so the trapped carbon remains trapped for prolonged periods of time.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Recent radiative forcing estimates arising from biophysical processes generally fall at the lower end of the AR5 assessed range. For instance, based on historical simulations from 13 CMIP6 models, Smith et al., (2020) estimated that the ERF from surface&#xA;albedo changes (including snow cover and leaf area) was -0.08 [-0.22 to 0.06] W m–2&#xA;since 1850. Similarly, based on simulations from 13 CMIP5 models, Lejeune et al., (2020) estimated the radiative forcing from&#xA;transitions between trees, crops, and grasslands was -0.11 [-0.16 to 0.04] W m-2&#xA;since 1860. Andrews et al.,&#xA;(2017) identified an ERF of -0.40 W m–2 since 1860, ascribing much of the effect to increases in albedo&#xA;(&lt;strong&gt;including the unmasking of underlying snow cover&lt;/strong&gt;); notably, however, the analysis was based on a single&#xA;model with a known tendency to overestimate the ERF (Collins et al., 2011).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;em&gt;(p. 2-28)&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="22632" LastEditorUserId="22632" LastEditDate="2021-10-28T15:38:54.967" LastActivityDate="2021-10-28T15:38:54.967" Title="Is cutting down boreal forest good or bad for our climate?" Tags="|climate-change|forest|deforestation|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23049" PostTypeId="2" ParentId="23047" CreationDate="2021-10-28T08:32:46.410" Score="6" Body="&lt;p&gt;You have a shape mismatch, as you are overwriting&lt;code&gt;xi&lt;/code&gt; and &lt;code&gt;yi&lt;/code&gt; using &lt;code&gt;np.meshgrid&lt;/code&gt;, then assigning wrong dimensions with &lt;code&gt;dim_lat&lt;/code&gt; and &lt;code&gt;dim_lon&lt;/code&gt; and eventually trying to fill &lt;code&gt;latitude&lt;/code&gt; and &lt;code&gt;longitude&lt;/code&gt; with your initial values of length 6.&lt;/p&gt;&#xA;&lt;p&gt;Try modifying the grid preparation and interpolation&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;# prepare a grid for interpolation&#xA;xi = np.arange(6.0, 14.0, 0.001)&#xA;yi = np.arange(48.0, 64.0, 0.001)&#xA;xi_mesh, yi_mesh = np.meshgrid(xi, yi)&#xA;&#xA;# interpolate&#xA;zi = griddata((lon, lat), temp, (xi_mesh, yi_mesh), method='linear')&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;.. and writing the values&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;# fill with values&#xA;latitude[:] = yi&#xA;longitude[:] = xi&#xA;value[0,:,:] = zi&#xA;value.grid_mapping = 'WGS84'&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="18907" LastActivityDate="2021-10-28T08:32:46.410" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23050" PostTypeId="2" ParentId="23047" CreationDate="2021-10-28T09:37:53.643" Score="7" Body="&lt;p&gt;I changed your model solution a little bit; but it's like Ingvar Lukas wrote in his answer: you redefined &lt;code&gt;xi&lt;/code&gt; and &lt;code&gt;yi&lt;/code&gt; in the process, so when you later on define the netCDF values for &lt;code&gt;lat&lt;/code&gt; and &lt;code&gt;lon&lt;/code&gt; you try to fill small 1D arrays with a 2D array. That is the source of your error.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import numpy as np&#xA;from scipy.interpolate import griddata&#xA;import xarray as xr&#xA;import pandas as pd&#xA;import rioxarray&#xA;import netCDF4 as nc4&#xA;import matplotlib.pyplot as plt&#xA;from shapely.geometry import Point&#xA;import geopandas as gpd&#xA;from pyproj import CRS&#xA;&#xA;CRS_3857 = CRS.from_epsg(3857)&#xA;CRS_wkt = CRS_3857.to_wkt(pretty=False)&#xA;print(CRS_wkt)&#xA;&#xA;# --- Input data....&#xA;lat = [50.1, 50.2, 50.3, 50.4, 50.5, 62]&#xA;lon = [ 8.1,  8.2,  8.3,  8.4,  8.5, 12]&#xA;temp = [1  ,  2  ,  3  ,  4  ,  5  ,  6]&#xA;&#xA;# Put into pandas Dataframe&#xA;df = pd.DataFrame(&#xA;    {&#xA;        'latitude': lat,&#xA;        'longitude': lon,&#xA;        'temp': temp&#xA;    }&#xA;)&#xA;&#xA;# Prepare geometry&#xA;pointShp = [Point(x, y) for x, y in zip(df.longitude, df.latitude)]&#xA;pointGpd = gpd.GeoDataFrame(df, geometry=pointShp, crs='EPSG:4326')&#xA;&#xA;# Reproject&#xA;point3857 = pointGpd.to_crs('EPSG:3857')&#xA;point3857['x'] = point3857.apply(lambda x: x.geometry.centroid.x, axis=1)&#xA;point3857['y'] = point3857.apply(lambda x: x.geometry.centroid.y, axis=1)&#xA;df = point3857[['x','y','temp']]&#xA;lon = list(df['x'])&#xA;lat = list(df['y'])&#xA;temp = list(df['temp'])&#xA;&#xA;# Proceed with your source code&#xA;# --- Project input data on a regular grid&#xA;xi = np.linspace(min(lon), max(lon), 500)&#xA;yi = np.linspace(min(lat), max(lat), 500)&#xA;xi, yi = np.meshgrid(xi, yi)&#xA;zi = np.ones_like(xi,dtype=np.float32) * np.NaN&#xA;# zi = griddata((lon, lat), temp, (xi, yi), method='linear')&#xA;for i in range(len(temp)):&#xA;    idx = np.argmin( np.sqrt( (xi-lon[i])**2 + (yi-lat[i])**2) )&#xA;    zi[np.unravel_index(idx, xi.shape)] = temp[i]&#xA;&#xA;# --- Check... =&amp;gt; LOOKS GOOD&#xA;plt.figure(figsize=(15,7))&#xA;plt.subplot(1,2,1)&#xA;plt.scatter(lon, lat, temp, temp)&#xA;plt.subplot(1,2,2)&#xA;plt.pcolor(xi, yi, np.where(np.isnan(zi),0,zi))&#xA;plt.show()&#xA;&#xA;# --- Open NetCDF file to write on&#xA;with nc4.Dataset('test.nc', 'w' , format='NETCDF3_CLASSIC') as ds:&#xA;    # --- Initialize the dimensions of the dataset&#xA;    dim_time = ds.createDimension('time', 0)&#xA;    dim_lat = ds.createDimension('lat', yi.shape[0])&#xA;    dim_lon = ds.createDimension('lon', xi.shape[1])&#xA;&#xA;    # --- Create the corresponding variables for the dimensions&#xA;    time = ds.createVariable('time', np.float32, 'time')&#xA;    latitude = ds.createVariable('lat', np.float32, 'lat')&#xA;    latitude.units = ['degrees north']&#xA;    latitude.axis  = ['Y']&#xA;    latitude.standard_name = ['latitude']&#xA;    longitude = ds.createVariable('lon', np.float32, 'lon')&#xA;    longitude.units = ['degrees east']&#xA;    longitude.axis = ['X']&#xA;    longitude.standard_name = ['longitude']&#xA;    &#xA;    # --- Fill with 1D (!) arrays of xi/yi, as the meshgrid returns 2D arrays...&#xA;    time[:] = 0&#xA;    latitude[:] = yi[:,0]&#xA;    longitude[:] = xi[0,:]&#xA;    &#xA;    # --- Create a coordinate reference system&#xA;    crs = ds.createVariable('CRS', 'c')&#xA;    crs.spatial_ref = CRS_wkt&#xA;&#xA;    # --- Ready the Temperature data field&#xA;    value = ds.createVariable('temperature', np.float32, ('time','lat','lon'))&#xA;    &#xA;    value.grid_mapping = 'CRS' # the crs variable name&#xA;    value.grid_mapping_name = 'latitude_longitude'&#xA;    &#xA;    # --- Fill with values&#xA;    value[0,:,:] = zi&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;That yields a georeferenced picture when loaded into QGIS (I reduced the step size of your &lt;code&gt;xi&lt;/code&gt; and &lt;code&gt;yi&lt;/code&gt; values to make the &lt;code&gt;pcolor&lt;/code&gt; step a bit more performant; but you can change it back in your code).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iWJAB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iWJAB.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1MyVt.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1MyVt.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12155" LastEditorUserId="12155" LastEditDate="2021-10-28T15:40:46.260" LastActivityDate="2021-10-28T15:40:46.260" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="23051" PostTypeId="1" AcceptedAnswerId="23055" CreationDate="2021-10-28T15:23:35.207" Score="7" ViewCount="314" Body="&lt;p&gt;Are wetlands a net source or net sink of GHGs? On the one hand, they store a lot of carbon. On the other hand, they emit methane, a potent green house gas.&lt;/p&gt;&#xA;" OwnerUserId="22632" LastActivityDate="2021-11-01T17:30:59.233" Title="Are wetlands a net source or net sink of GHGs?" Tags="|climate-change|greenhouse-gases|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23052" PostTypeId="1" CreationDate="2021-10-28T15:53:16.663" Score="3" ViewCount="57" Body="&lt;p&gt;Also, would it matter if a particular type of greenhouse gas molecule reflected rather than absorbed and then re-emitted light?  Would its GWP be higher or lower?&lt;/p&gt;&#xA;&lt;p&gt;Perhaps this is more of a pure physics question than an applied physics, Earth-science one, but I am very curious....&lt;/p&gt;&#xA;" OwnerUserId="20985" LastActivityDate="2021-10-28T15:53:16.663" Title="Do greenhouse gases absorb and re-emit photons or reflect them diffusely? Or both? (CO2, CH4, H2O, N20, HFC-134a, etc.)" Tags="|climate-change|geophysics|climate|climatology|solar-terrestrial-physics|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23053" PostTypeId="1" CreationDate="2021-10-29T01:10:48.690" Score="5" ViewCount="38" Body="&lt;p&gt;I've heard that estuaries like Chesapeake Bay produce a lot of methane during anoxic conditions. Is there a chance of these estuaries emitting significant amounts of CH&lt;sub&gt;4&lt;/sub&gt; in the future (because of the growth of dead zones/less O&lt;sub&gt;2&lt;/sub&gt;)? Can these emissions affect global climate?&lt;/p&gt;&#xA;" OwnerUserId="22045" LastEditorUserId="2470" LastEditDate="2021-10-29T09:24:42.627" LastActivityDate="2021-10-29T09:24:42.627" Title="Carbon emission from estuaries" Tags="|climate-change|oceanography|geochemistry|oxygen|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23054" PostTypeId="2" ParentId="23019" CreationDate="2021-10-29T05:48:03.780" Score="2" Body="&lt;p&gt;When core samples are taken in the field, their orientation must first be measured, generally with standard field tools such as a Brunton. These high quality, professional compasses are good to +/- 1 degree, which, additionally, are only as good as the stated declination for that day and location on Earth, which is probably around +/- 1 degrees. Add to that any errors in inclination caused by compaction and deformation and you have large uncertainties in predicted latitudes.&lt;/p&gt;&#xA;&lt;p&gt;So, before the sample even makes it back to the paleomag lab, its orientation may already off by at least a few degrees, nevermind the inclination. This is why paleomagnetic data from a single sample is largely useless; many samples of the same age must be taken and a library of orientations built and compared to a global geomagnetic model. Even with that data, you may be looking at errors of up to 10 degrees.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2021-10-29T05:48:03.780" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23055" PostTypeId="2" ParentId="23051" CreationDate="2021-10-29T12:33:53.250" Score="5" Body="&lt;p&gt;Depends on a number of factors. The main issue is the balance of carbon sequestration in &lt;a href=&quot;https://en.wikipedia.org/wiki/Peat&quot; rel=&quot;noreferrer&quot;&gt;peat&lt;/a&gt; versus methane emission if they're trapping more carbon dioxide through growth than their equivalent emissions to rot/burning then they're a net sink. Most undisrupted wetlands are large net sinks taking in many times more carbon than they emit even taking into account the relatively high impact of methane measured against carbon dioxide. The big problem is that many wetlands have been disrupted in one or more ways leading to their degradation and changing the balance of uptake/storage vs emission those that are worse effected have become net emitters of carbon.&lt;/p&gt;&#xA;&lt;p&gt;There are of course other issues to consider, like the alternative land use, a waterlogged grazing pasture can be a much larger emitter of methane per acre than the bog that occupied the same site until it was drained and it sequesters minimal carbon. Peat land turned over to managed leguminous hardwood forestry may be able to sequester just as much carbon but with far less methane.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="10735" LastEditDate="2021-10-29T12:38:55.297" LastActivityDate="2021-10-29T12:38:55.297" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23057" PostTypeId="1" CreationDate="2021-10-30T20:42:41.667" Score="3" ViewCount="24" Body="&lt;p&gt;Where can I find Free Swell Index data for Clays for the Cambridgeshire region, United Kingdom?&lt;/p&gt;&#xA;&lt;p&gt;Surely this must have been performed at some point even though there are more sophisticated tests. I've searched the NERC Open Research Archive that includes the British Geological Survey but I have had no luck.&lt;/p&gt;&#xA;&lt;p&gt;The Free Swell Index for soil is the easiest method for me to perform and I do not need that great accuracy but I would like some data from measurements in the Cambridgeshire region, United Kingdom for comparison. I seemed to have boulder clay (see light blue on map &lt;a href=&quot;https://largeimages.bgs.ac.uk/iip/mapsportal.html?id=1003300&quot; rel=&quot;nofollow noreferrer&quot;&gt;Biggleswade sheet 204&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="24765" LastActivityDate="2021-10-30T20:42:41.667" Title="Where can I find soil Free Swell Index values for the Cambridgeshire region, United Kingdom?" Tags="|measurements|soil|field-measurements|geologic-layers|in-situ-measurements|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23058" PostTypeId="1" AcceptedAnswerId="23064" CreationDate="2021-10-30T21:41:17.903" Score="2" ViewCount="93" Body="&lt;p&gt;I am using land use regression with machine learning to create an air pollution model. However, almost all tiles I can find using Python and Folium contain text, which my intuition says cannot possibly be a good thing. I've seen papers use drawn maps for this task, and I am not convinced they are better than satellite images...&lt;/p&gt;&#xA;&lt;p&gt;Does anybody here have experience with extracting city maps for air pollution modelling? Which ones should I use? Is satellite data better than drawn maps?&lt;/p&gt;&#xA;" OwnerUserId="24467" LastActivityDate="2022-03-31T10:07:45.777" Title="Folium/Leaflet tiles for air pollution modelling" Tags="|air-pollution|mapping|python|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23059" PostTypeId="1" AcceptedAnswerId="23060" CreationDate="2021-11-01T03:26:47.887" Score="13" ViewCount="14301" Body="&lt;p&gt;I am curious to know if it would be highly probable that if the Bennu asteroid were to hit the Earth in 2182, and the point of impact is within a 500 mile radius of Yellowstone National Park, will it most likely trigger a super volcano at Yellowstone?&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;If an impact were to occur, the expected kinetic energy associated with the collision would be 1,200 megatons in TNT equivalent (for comparison, TNT equivalent of Little Boy was approx 0.015 megaton)...&amp;quot;&lt;br /&gt;&#xA;— &lt;a href=&quot;https://en.wikipedia.org/wiki/101955_Bennu&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I am thinking that such an impact would send massive shockwaves through the ground in all directions and that these shockwaves could cause huge cracks in the rock dome that covers the giant magma chamber at Yellowstone.&lt;/p&gt;&#xA;&lt;p&gt;So, if the Bennu asteroid were to hit within a 500 mile radius of Yellowstone National Park, will it trigger a super volcano at Yellowstone?&lt;/p&gt;&#xA;" OwnerUserId="23275" LastEditorUserId="11426" LastEditDate="2021-11-04T15:52:02.883" LastActivityDate="2021-11-04T15:52:02.883" Title="If the Bennu asteroid were to hit within a 500 mile radius of Yellowstone National Park, will it trigger a super volcano at Yellowstone?" Tags="|geology|volcanology|earthquakes|asteroids|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23060" PostTypeId="2" ParentId="23059" CreationDate="2021-11-01T05:23:02.163" Score="17" Body="&lt;p&gt;Maybe but it will depend on the state of the magma chamber under the caldera. If the magma chamber is already under enough pressure and has a super-eruptive quantity of liquid melt in it then the shock of a large bolide impact may act to &amp;quot;pop the cork&amp;quot; so to speak initiating a super eruption. I can also make an argument for shock nucleation of gas in the melt creating a pressure surge but that will depend on melt composition. So maybe &lt;em&gt;&lt;strong&gt;BUT&lt;/strong&gt;&lt;/em&gt; the right conditions are going to have to exist such that any similar shock, or none at all, would cause a super volcanic eruption anyway, the volcano will have to be close to eruption before the impact in other words.&lt;/p&gt;&#xA;&lt;p&gt;Note that the Yellowstone caldera does go through cycles of seeming to be close to erupting and then backing off again so if the hit comes during a time of high pressure it could create an eruption that wouldn't have happened otherwise.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2021-11-01T05:23:02.163" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23061" PostTypeId="1" AcceptedAnswerId="23065" CreationDate="2021-11-01T07:11:36.660" Score="2" ViewCount="139" Body="&lt;p&gt;I've heard that the concentration of CO&lt;sub&gt;2&lt;/sub&gt; has been increased in the air.&lt;/p&gt;&#xA;&lt;p&gt;It should have increased atmospheric pressure, right?&lt;/p&gt;&#xA;" OwnerUserId="24773" LastEditorDisplayName="user20559" LastEditDate="2021-11-01T07:32:39.610" LastActivityDate="2021-11-01T17:27:07.903" Title="How does atmospheric pressure remains constant even though we have released 43 billion tons of $\ce{CO2}$ in one year?" Tags="|atmosphere|earth-observation|greenhouse-gases|earth-system|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="23062" PostTypeId="2" ParentId="23061" CreationDate="2021-11-01T07:30:41.440" Score="2" Body="&lt;p&gt;We have issued around 200 ppm of CO&lt;sub&gt;2&lt;/sub&gt;. That means 0,02 % of the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;Furthermore the &lt;a href=&quot;https://en.wikipedia.org/wiki/Combustion#Complete&quot; rel=&quot;nofollow noreferrer&quot;&gt;combustion reaction&lt;/a&gt; consumes O&lt;sub&gt;2&lt;/sub&gt;. Also part of the CO&lt;sub&gt;2&lt;/sub&gt; dissolves in the ocean because of &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Henry%27s_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Henry's law&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The variation of atmospheric pressure due to industrial activity is negligible, much less than 0,02%.&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-11-01T12:52:23.883" LastActivityDate="2021-11-01T12:52:23.883" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23063" PostTypeId="2" ParentId="23059" CreationDate="2021-11-01T09:22:37.570" Score="21" Body="&lt;p&gt;There is actually an hypothesis that large asteroid impacts can trigger volcanism at the antipodal point, where the seismic energy of the impact focuses. On Earth, it has been suggested that the Chicxulub impact could have triggered the main phase of the antipodal (and synchronous) Deccan Traps eruption (&lt;a href=&quot;https://doi.org/10.1130/B31167.1&quot; rel=&quot;noreferrer&quot;&gt;Richards et al., 2015&lt;/a&gt;). On Mars, the same process has been suggested (&lt;a href=&quot;https://doi.org/10.1006/icar.1994.1116&quot; rel=&quot;noreferrer&quot;&gt;Williams &amp;amp; Greeley, 1994&lt;/a&gt;): Alba Mons, the largest volcano of the planet, is antipodal to Hellas Planitia, the largest impact structure. So, according to this hypothesis, for an impact to trigger an eruption at Yellowstone, it would have to occur at the antipodal point of the caldera, which is somewhere in the Indian Ocean, north from Kerguélen.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;(Note: Part of this answer is copy/pasted from &lt;a href=&quot;https://astronomy.stackexchange.com/a/39589/34513&quot;&gt;my answer&lt;/a&gt; to &lt;a href=&quot;https://astronomy.stackexchange.com/q/39588/34513&quot;&gt;What if a global killer hit Mars?&lt;/a&gt; at Astronomy SE.)&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2021-11-02T08:59:54.953" LastActivityDate="2021-11-02T08:59:54.953" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23064" PostTypeId="2" ParentId="23058" CreationDate="2021-11-01T09:44:57.540" Score="1" Body="&lt;p&gt;Satellite data is more noisy than rasterized vector maps; &lt;a href=&quot;https://arxiv.org/pdf/2002.07493.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Steininger et al found that&lt;/a&gt; OpenStreetMap input was superior for their CNN-based land use regression model. They tested OpenStreetMap, Google Maps, Satellite images from Google maps and a combination of OpenStreetMap and Google Maps Satellite. The model trained on inputs from OpenStreetMap outperformed all of the others.&lt;/p&gt;&#xA;" OwnerUserId="24467" LastActivityDate="2021-11-01T09:44:57.540" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23065" PostTypeId="2" ParentId="23061" CreationDate="2021-11-01T17:27:07.903" Score="2" Body="&lt;p&gt;The Earth's atmosphere has a mass of about 5.15×10^18 kg or 5.15 Quadrillion Metric tons, CO2 human outputs since start of the Industrial revolution amount to 654 billion tons, or 1/7,800 th of it's overall mass. Also CO2 emissions came from consuming existing atmospheric oxygen. The Carbon that was added using stoichiometric calculations; Only 27% of CO2's mass is carbon so  of the 654 Billion tons of CO2 added since 1850's, only 176.58 billion tons came from added Carbon or 1/29,000th the the Atmospheric mass. Not enough to do anything to adjust overall atmospheric pressure.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-11-01T17:27:07.903" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23066" PostTypeId="2" ParentId="23051" CreationDate="2021-11-01T17:30:59.233" Score="0" Body="&lt;p&gt;Carbon neutral, but overall massive carbon sink. Rotting vegetation produces CO2, Growing vegetation consumes it. However many wetland soils are oxygen deprived, so soil chemistry preserves carbon mass and buries &lt;a href=&quot;https://en.wikipedia.org/wiki/Peat&quot; rel=&quot;nofollow noreferrer&quot;&gt;under sediments&lt;/a&gt;. This is how coal &lt;a href=&quot;https://en.wikipedia.org/wiki/Carboniferous&quot; rel=&quot;nofollow noreferrer&quot;&gt;formed&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-11-01T17:30:59.233" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23067" PostTypeId="2" ParentId="23059" CreationDate="2021-11-01T18:51:09.527" Score="9" Body="&lt;p&gt;Bennu is about 470m diameter, and will impact at a &amp;quot;mere&amp;quot; 11.3km/s.&lt;/p&gt;&#xA;&lt;p&gt;At the impact site it would blast a crater some 3 miles wide and 1500 ft deep, a very respectable impact indeed. The energy of impact is equivalent to a 6.6 moment magnitude earthquake at the surface at the impact location.&lt;/p&gt;&#xA;&lt;p&gt;500 miles away, the impact will be neither felt not heard by human senses, but should be quite detectable by seismic instruments. This level of disturbance is unlikely to bother the magma under Yellowstone, it got shaken &lt;em&gt;much&lt;/em&gt; harder during the 2011 Japanese earthquake.&lt;/p&gt;&#xA;&lt;p&gt;Closer impact would be a different story, and an impact anywhere directly above the magma chamber will be a very bad thing. How close it would need to be is a difficult question though.&lt;/p&gt;&#xA;" OwnerUserId="22994" LastActivityDate="2021-11-01T18:51:09.527" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="23069" PostTypeId="1" CreationDate="2021-11-02T12:08:07.577" Score="3" ViewCount="134" Body="&lt;p&gt;Looking at the layer &amp;quot;Air Quality&amp;quot; on my iOS weather app there seem to be large circular areas of air pollution outside of large cities.&lt;/p&gt;&#xA;&lt;p&gt;What could be the cause for such phenomena?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PuaTO.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PuaTO.jpg&quot; alt=&quot;2021-11-02 04:00 PT&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;UPDATE&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I looked at the same region after one day. The blob near Reno seems to persist. The blob in Montana nearly disappeared.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EWRde.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EWRde.jpg&quot; alt=&quot;2021-11-03 02:00 PT&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I could not find any incident in Montana to explain the temporary blob.&lt;/p&gt;&#xA;&lt;p&gt;The blob near Reno has a diameter of min. 50km and is located directly over Yerington. The only incident I found in this area was on October 27. There was a car crash which could/should not be the cause for this.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;EDIT&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;The source of the weather app is linked to this:&#xA;&lt;a href=&quot;https://air.plumelabs.com/en/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://air.plumelabs.com/en/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here the Plume Index is shown and the blob near Reno is clearly visible.&lt;/p&gt;&#xA;" OwnerUserId="24788" LastEditorUserId="24788" LastEditDate="2021-11-03T09:58:28.163" LastActivityDate="2021-11-06T08:03:28.850" Title="What is the cause for large circular areas of air pollution?" Tags="|air-pollution|air-quality|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23070" PostTypeId="1" CreationDate="2021-11-02T14:05:50.587" Score="3" ViewCount="35" Body="&lt;p&gt;I processed a lot of modeled climate data from CMIP and I want to check that I have not made any errors. I think the best way to do this is to somehow evaluate the data I produced geographically against other observational datasets.&lt;/p&gt;&#xA;&lt;p&gt;In my processing I create a climatology of tasmax for the modeled historical data (1990-2010) and do some other 'tinkering'.&lt;/p&gt;&#xA;&lt;p&gt;How can I check that my final tasmax 'product' is still realistic (i.e. how well does it match up to observations?)? Should I directly difference it from the observations to see how far my climatology differs? Are there any other methods that will highlight spatial anomalies in my new data set, if they exist?&lt;/p&gt;&#xA;" OwnerUserId="24395" LastEditorUserId="2470" LastEditDate="2021-11-02T16:10:35.500" LastActivityDate="2021-11-02T16:10:35.500" Title="What is the best way to check for technical validity of climate data?" Tags="|climate|data-analysis|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23072" PostTypeId="2" ParentId="23069" CreationDate="2021-11-02T16:54:54.793" Score="3" Body="&lt;p&gt;The blob near Reno Nevada is not the Anaconda copper mine, which &lt;a href=&quot;https://ndep.nv.gov/land/abandoned-mine-lands/anaconda-home&quot; rel=&quot;nofollow noreferrer&quot;&gt;ceased processing activities in 2000 and is currently being rehabilitated.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The blob of airborne pollution is most likely due to the gas fired power station, &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_power_stations_in_Nevada&quot; rel=&quot;nofollow noreferrer&quot;&gt;Frank A. Tracy&lt;/a&gt;, in Storey County. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Anaconda_Copper_Mine_(Nevada)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Anaconda mine&lt;/a&gt; has co-ordinates of 38° 59' N, 119° 12'W (38.983° N, 119.2°). The co-ordinates of the power station are 39.5625°N 119.5250°W.&lt;/p&gt;&#xA;&lt;p&gt;Regarding the blob in Montana, that coincides with the &lt;a href=&quot;https://en.wikipedia.org/wiki/Powder_River_Basin&quot; rel=&quot;nofollow noreferrer&quot;&gt;Powder River Basin&lt;/a&gt;, a large coal mining region. &lt;a href=&quot;https://en.wikipedia.org/wiki/Broadus%2C_Montana&quot; rel=&quot;nofollow noreferrer&quot;&gt;Broadus, Montana&lt;/a&gt; is in the southeastern corner of the State. Its co-ordinates are 45° 26' 34&amp;quot; N, 105° 24'  33&amp;quot; W (45.576° N, 105.409° W). It is located near a number of &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_power_stations_in_Montana&quot; rel=&quot;nofollow noreferrer&quot;&gt;power stations in Montana&lt;/a&gt;, such as Colstrip Steam Electric Station with co-ordinates 45.8831°N 106.614°W.&lt;/p&gt;&#xA;&lt;p&gt;The blob in Washington is near the town of &lt;a href=&quot;https://en.wikipedia.org/wiki/Colville%2C_Washington&quot; rel=&quot;nofollow noreferrer&quot;&gt;Colville&lt;/a&gt; (48 N, 117 W) which is near the &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_power_stations_in_Washington&quot; rel=&quot;nofollow noreferrer&quot;&gt;Boulder Park Generation Station&lt;/a&gt; (47 N, 117 W).&lt;/p&gt;&#xA;&lt;p&gt;So those, significant sized, blobs were associated with power stations. The other blobs may also be due to fossil fueled power stations.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-11-02T17:03:22.833" LastActivityDate="2021-11-02T17:03:22.833" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23073" PostTypeId="1" CreationDate="2021-11-03T07:54:43.873" Score="0" ViewCount="284" Body="&lt;p&gt;Is there a le Chatilier principle within Earth - Earth heats up causes global warming resulting in polar ice melt resulting in higher sea levels which takes up the extra earth temp and the over correction will result in heat drop to ice age and forming of polar caps and so on... Is global warming normal for Earth and the anthropogenic effect of CO&lt;sub&gt;2&lt;/sub&gt; pollution overstated?&lt;/p&gt;&#xA;" OwnerUserId="24797" LastEditorUserId="2470" LastEditDate="2021-11-03T09:22:07.720" LastActivityDate="2021-11-04T05:21:36.720" Title="After global warming, does an ice age occur because the polar caps have melted and caused more water to absorb the gloabl warming" Tags="|sea-level|earth-system|ice-age|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23074" PostTypeId="2" ParentId="23073" CreationDate="2021-11-03T08:58:07.927" Score="3" Body="&lt;p&gt;Seems a valid enough question.  But what stand out to me is that the area of Earth covered by water doesn't appear to change by a notable percentage in a rough estimate of a world without ice:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gGDDY.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gGDDY.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;(found on &lt;a href=&quot;https://www.reddit.com/r/MapPorn/comments/19sp27/map_of_a_world_without_icecaps_1440x720/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reddit&lt;/a&gt; without much detail, seems reasonable and similar to other videos, other than the flawed expansion of inland seas)&lt;/p&gt;&#xA;&lt;p&gt;And so the energy diverted into oceans from lost land is reasonably small already.  And then there's the emergence of &lt;a href=&quot;https://www.nasa.gov/mission_pages/icebridge/multimedia/fall11/antarctica-US.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Antarctica&lt;/a&gt; and the fact so much &lt;a href=&quot;https://en.wikipedia.org/wiki/Albedo&quot; rel=&quot;nofollow noreferrer&quot;&gt;high albedo&lt;/a&gt; (highly reflective) ice is eliminated over water... so it would seem pretty clear there wouldn't be a massive new energy tie up that could reverse things.  And of course the energy going into the oceans isn't lost, it's just often slower to be shared with the globe, so even that aspect is a heat gain in the long run (water has one of the lowest average albedos).  Unless the initial melting expanded ocean size greatly before the larger landmasses cleared of ice, it would seem impossible there could be any potential for a reversal along the methods you suggest.&lt;/p&gt;&#xA;&lt;p&gt;Another feedback avenue, changes in cloud coverage, looks like a more nuanced topic that I believe has been debated a bit more over the years in the field, but you'd have to ask about it separately and hopefully get response from people with more expertise on that topic.&lt;/p&gt;&#xA;&lt;p&gt;As far as I remember it, Le Chatilier's Principle doesn't indicate a system tends to overcorrect, just that the new equilibrium will in some way remove some of the input... a warmer Earth would emit more energy indeed... but that isn't initiating a cooling process, just setting it up to reach a new stable temperature value eventually.&lt;br /&gt;&#xA;And there are plenty of systems where small changes unlock additional factors that accelerate the change, until they are accounted for and the equilibrium includes those altered shifts.&lt;/p&gt;&#xA;&lt;p&gt;So, while I can be a skeptic at times in the topic as a whole, and do very much think it's good to consider things fairly and honestly, nothing I see in the idea that expanded oceans would absorb more energy, or from Le Chatelier's Principle, or from the general idea that &amp;quot;global warming is normal&amp;quot; (because warming and cooling have happened before?) would offer viable support at least that the Earth would overcome such changes. And so I don't see your topics giving any support at all to allow for such a sweeping claim as &amp;quot;man's effect of CO2 pollution [is] overstated&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2021-11-03T09:11:09.270" LastActivityDate="2021-11-03T09:11:09.270" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23076" PostTypeId="1" AcceptedAnswerId="23095" CreationDate="2021-11-03T12:30:30.633" Score="3" ViewCount="88" Body="&lt;p&gt;I am programming an app that consist in 180 mineral sheets of interest for geology students.&lt;/p&gt;&#xA;&lt;p&gt;My database have the following fileds:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Identifier&lt;/li&gt;&#xA;&lt;li&gt;Name&lt;/li&gt;&#xA;&lt;li&gt;Name 2&lt;/li&gt;&#xA;&lt;li&gt;Type&lt;/li&gt;&#xA;&lt;li&gt;Class&lt;/li&gt;&#xA;&lt;li&gt;Formula&lt;/li&gt;&#xA;&lt;li&gt;System&lt;/li&gt;&#xA;&lt;li&gt;Environment1&lt;/li&gt;&#xA;&lt;li&gt;Environment2&lt;/li&gt;&#xA;&lt;li&gt;Environment3&lt;/li&gt;&#xA;&lt;li&gt;Environment4&lt;/li&gt;&#xA;&lt;li&gt;Environment5&lt;/li&gt;&#xA;&lt;li&gt;Habit&lt;/li&gt;&#xA;&lt;li&gt;Color&lt;/li&gt;&#xA;&lt;li&gt;Diaphaneity&lt;/li&gt;&#xA;&lt;li&gt;Luster&lt;/li&gt;&#xA;&lt;li&gt;Streak&lt;/li&gt;&#xA;&lt;li&gt;Density&lt;/li&gt;&#xA;&lt;li&gt;Hardness&lt;/li&gt;&#xA;&lt;li&gt;Cleavage&lt;/li&gt;&#xA;&lt;li&gt;Fracture&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;For example the entry for golds look like:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;INSERT INTO MINE180 VALUES('1','gold','gold','Non sillicates.','Native Elements.','Au','Cubic.','Hydrothermal: Associated to quartz veins.','Sedimentary: Placers.','Magmatic: IOCG deposits.','','','Octaedrical crystals.','Characteristic yellow.','Opaque.','Metallic.','Characteristic yellow.','19.3','2.5-3','---','Splintered, jagged.');&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;I am going to generate questions such as:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Wich mineral belongs to inosillicates class?&lt;/p&gt;&#xA;&lt;p&gt;a) Calcosine&lt;/p&gt;&#xA;&lt;p&gt;b) Augite&lt;/p&gt;&#xA;&lt;p&gt;c) Quartz&lt;/p&gt;&#xA;&lt;p&gt;d) Pirope&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I can generate questions from all the fields ot the database but I don't think questions about physical-chemical properties are of use for the students. Unless density or hardness maybe.&lt;/p&gt;&#xA;&lt;p&gt;What fields would you use to generate the questions that the students of geology and minning are going to check?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-11-04T13:11:26.457" LastActivityDate="2021-11-05T14:44:18.120" Title="What questions to ask to students from a mineral guide dataset?" Tags="|geology|mineralogy|minerals|economic-geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23077" PostTypeId="1" AcceptedAnswerId="23081" CreationDate="2021-11-03T16:29:04.880" Score="1" ViewCount="58" Body="&lt;p&gt;I'm new in hydrology sciences and for my work, I have to differentiate solid precipitation time series and liquid precipitation from total precipitation time series. My data are from a meteorological station and the figure below is to illustrate the followings.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6uOIA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6uOIA.png&quot; alt=&quot;Data&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Generally, we consider that 10 cm of snow = 1 cm of equivalent water. But, following a number of paramters, this ratio can be great or less. But let us suppose that the ratio snow/water = 100cm/1cm (which is probably wrong), despite this very disproportionate ratio, it is impossible to show that Total precipitation &amp;gt;= Solid precipitation (snow) at dates where it snowed.&lt;/p&gt;&#xA;&lt;p&gt;My questions are : What total precipitation means here? Isn't it the sum of solid and liquid precipitation? Why equivalent water of snow is always superior to total precipitation? Does total precipitation already take into account the water equivalent of snow?&lt;/p&gt;&#xA;&lt;p&gt;Here is the link to the site where I got the data (you can enter an Airport name to get some data to see what is going on, if necessary): &lt;a href=&quot;https://meteostat.net/en/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://meteostat.net/en/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24724" LastEditorDisplayName="user20559" LastEditDate="2021-11-04T11:07:05.270" LastActivityDate="2021-11-04T18:39:15.807" Title="Does total precipitation have different meanings?" Tags="|meteorology|climate|hydrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23078" PostTypeId="2" ParentId="12685" CreationDate="2021-11-03T21:06:40.480" Score="2" Body="&lt;p&gt;Human metabolic heat doesn't add energy that was not already there.&lt;/p&gt;&#xA;&lt;p&gt;The metabolic heat human bodies produce comes from energy supplied by the food we eat. The energy in that food came from solar energy converted to carbohydrates and proteins by photosynthesis and plant metabolism, either directly (as plant based food) or indirectly (as food for animal products and meat) - it doesn't add energy that was not already present in the climate system.&lt;/p&gt;&#xA;&lt;p&gt;But the fossil fuel burning that contributed to cultivation, transport, storage and cooking &lt;em&gt;do&lt;/em&gt; add energy not already present - from the heat of combustion of energy in long term carbon sinks added directly and an estimated &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2008GL036465&quot; rel=&quot;nofollow noreferrer&quot;&gt;100x that heat added to the climate system from enhanced greenhouse effect&lt;/a&gt; indirectly from the CO2 released.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2021-11-03T21:06:40.480" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23079" PostTypeId="1" CreationDate="2021-11-03T23:33:43.320" Score="2" ViewCount="178" Body="&lt;p&gt;I need to do a &amp;quot;how do different 'Earth's spheres' interact with each other&amp;quot; and I'm trying to figure out how the hydrosphere would affect the lithosphere if the ozone layer were to disappear. 'Ozone Depletion.'&lt;/p&gt;&#xA;&lt;p&gt;This is a project for my High school environmental science course.&lt;/p&gt;&#xA;" OwnerUserId="24805" LastActivityDate="2021-11-04T05:23:15.017" Title="What role does the hydrosphere play in tectonic plate convection?" Tags="|plate-tectonics|ozone|lithosphere|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23081" PostTypeId="2" ParentId="23077" CreationDate="2021-11-04T04:04:12.883" Score="4" Body="&lt;p&gt;Figured out what it's doing by comparing results for the site at &lt;a href=&quot;https://meteostat.net/en/station/72528?t=2020-12-25/2021-01-08&quot; rel=&quot;nofollow noreferrer&quot;&gt;Buffalo Airport&lt;/a&gt; with &lt;a href=&quot;https://www.weather.gov/wrh/Climate?wfo=buf&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA NOWData&lt;/a&gt;... for December 26th and 27th, 2020 it showed (after converting NOAA data from inches to mm):&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th&gt;date&lt;/th&gt;&#xA;&lt;th&gt;MS Total Precip&lt;/th&gt;&#xA;&lt;th&gt;MS Snow&lt;/th&gt;&#xA;&lt;th&gt;NOAA Precip&lt;/th&gt;&#xA;&lt;th&gt;NOAA New Snow&lt;/th&gt;&#xA;&lt;th&gt;NOAA Snow Depth&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;26&lt;/td&gt;&#xA;&lt;td&gt;37.6 mm&lt;/td&gt;&#xA;&lt;td&gt;200 mm&lt;/td&gt;&#xA;&lt;td&gt;37.592 mm&lt;/td&gt;&#xA;&lt;td&gt;467.36 mm&lt;/td&gt;&#xA;&lt;td&gt;203.2 mm&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;27&lt;/td&gt;&#xA;&lt;td&gt;0 mm&lt;/td&gt;&#xA;&lt;td&gt;&lt;strong&gt;410 mm&lt;/strong&gt;&lt;/td&gt;&#xA;&lt;td&gt;Trace&lt;/td&gt;&#xA;&lt;td&gt;Trace&lt;/td&gt;&#xA;&lt;td&gt;406.4 mm&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;&#xA;&lt;p&gt;So the total precip is what I would expect, a liquid water equivalent, matching with the NWS value, which I'm familiar with using for many years.&lt;/p&gt;&#xA;&lt;p&gt;The problem is your meteostat site is giving the snow DEPTH in the snow column... so a measure of how much snow is sitting on the ground (taken early in the day... an IOWA NWS site &lt;a href=&quot;https://www.weather.gov/dvn/snowmeasure&quot; rel=&quot;nofollow noreferrer&quot;&gt;suggests at 7 AM&lt;/a&gt;), not how much fell in the day, and you won't be able to calculate from it to get total snowfall (because melting or lack thereof and compacting mean you can't just count differences... as even on this date, the 470 mm only became 210 mm of extra snow depth)&lt;/p&gt;&#xA;&lt;p&gt;I guess that's kind of the de facto data taken at stations, as measuring accumulation directly &lt;a href=&quot;https://www.weather.gov/media/ffc/snow_measurement_guidelines.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;can only be reasonably done with more frequent measurements on a swept-clean snowboard&lt;/a&gt;, which is contrary to station automation and probably only done on site at significant airports and weather offices?  So for most places, that's the best direct data you have :-(  The US NWS also produces &lt;a href=&quot;https://water.weather.gov/precip/&quot; rel=&quot;nofollow noreferrer&quot;&gt;precipitation&lt;/a&gt; and &lt;a href=&quot;https://www.nohrsc.noaa.gov/snowfall_v2/&quot; rel=&quot;nofollow noreferrer&quot;&gt;snow&lt;/a&gt; map interpolations from radar and station data, but not sure such a dataset exists for other places in the world :-(  So not sure how hydrologists get snowfall data, without someone going out to these places and doing longterm data collection?  Must interpolate from nearby stations or use model data or such???&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2021-11-04T18:39:15.807" LastActivityDate="2021-11-04T18:39:15.807" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23083" PostTypeId="2" ParentId="23079" CreationDate="2021-11-04T05:23:15.017" Score="1" Body="&lt;p&gt;Lubrication.&#xA;Not to mention hydrothermal vents which feat ecosystems that at the depth do not depend on sunlight&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-11-04T05:23:15.017" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23084" PostTypeId="2" ParentId="12685" CreationDate="2021-11-04T05:30:55.743" Score="0" Body="&lt;p&gt;No. Humans obtain energy by the consumption of food, namely carbohydrates (grains) For a typical human body, these energy losses are mostly thermal, in form of body heat. Depending on the activity and the environment, the body dissipates approximately 290 and 3800 kilojoule of thermal energy per hour, translating to a power of 80-1050 Watts (Average 40 kilojoules per person per day). With 7.8 billion people 380 Terajoules. By comparison;An average hurricane stores thermal energy of over 50 Quintillion JOULES! 13,000x more energy&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-11-04T05:30:55.743" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23085" PostTypeId="1" CreationDate="2021-11-04T14:24:14.937" Score="1" ViewCount="30" Body="&lt;p&gt;I need to calculate various variables for Alluvial Fans in ArcMap such as Fan area, gradient, angle subtended by fan. The data I am using is SRTM 1 Arc-Second Global. I am attempting to map and measure fans for the first time in ArcMap and would like to understand the way in which I can go about doing this.&lt;/p&gt;&#xA;&lt;p&gt;Also - should I be using the SRTM Non-Void data instead?&lt;/p&gt;&#xA;" OwnerUserId="24808" LastEditorUserId="2470" LastEditDate="2021-11-04T15:29:42.927" LastActivityDate="2021-11-04T15:29:42.927" Title="Mapping and calculating morphometric variables for Alluvial Fans in ArcMap?" Tags="|geomorphology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23086" PostTypeId="1" AcceptedAnswerId="23096" CreationDate="2021-11-04T19:42:54.107" Score="9" ViewCount="149" Body="&lt;p&gt;It may be a silly question but why does the Arctic warm so fast despite being so white (&amp;quot;albedo&amp;quot; is the word, I believe)? Isn't all that whiteness supposed to deflect all those pesky sun rays back into space (or wherever)? I heard on BBC that they &lt;a href=&quot;https://www.bbc.com/news/av/world-asia-58820950&quot; rel=&quot;nofollow noreferrer&quot;&gt;use&lt;/a&gt; white paint in India to paint rooftops so that it's not so scorching hot inside&lt;/p&gt;&#xA;" OwnerUserId="22632" LastEditorUserId="22632" LastEditDate="2021-11-09T00:10:43.483" LastActivityDate="2021-11-09T00:10:43.483" Title="Why does the Arctic warm so fast despite being so white?" Tags="|climate-change|arctic|" AnswerCount="4" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23088" PostTypeId="2" ParentId="23086" CreationDate="2021-11-05T01:59:43.697" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;So how is climate change and associated global heating driving Arctic amplification? This amplification is primarily caused by melting ice — a process that is increasing in the Arctic at a rate of 13% per decade.&lt;br /&gt;&#xA;Ice is more reflective and less absorbent of sunlight than land or the surface of an ocean. When ice melts, it typically reveals darker areas of land or sea, and this results in increased sunlight absorption and associated warming.&lt;br /&gt;&#xA;Polar amplification is much stronger in the Arctic than in Antarctica. This difference is because the Arctic is an ocean covered by sea ice, while Antarctica is an elevated continent covered in more permanent ice and snow.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://council.science/current/blog/climate-explained-why-is-the-arctic-warming-faster-than-other-parts-of-the-world/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Steve Turton, Adjunct Professor of Environmental Geography at CQUniversity Australia.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2021-11-05T01:59:43.697" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23089" PostTypeId="1" AcceptedAnswerId="23090" CreationDate="2021-11-05T10:12:42.487" Score="2" ViewCount="558" Body="&lt;p&gt;Sorry for the stupid question, but I have been unable to answer it even after wasting time googleing for a while... I know there are several climate-changes scenarios, and I know the several climatic databases offering surfaces (rasters) with those scenarios. However, I want to try some calculations on my own, for which I am looking for the mathematics behind these models (the different scenarios) or some code (preferably in R). Any suggestion?&lt;/p&gt;&#xA;" OwnerUserId="14509" LastEditorUserId="6298" LastEditDate="2021-11-07T09:17:21.500" LastActivityDate="2022-11-24T16:48:52.750" Title="Looking for the mathematics so I can run climate change simulations" Tags="|climate-change|climate-models|r|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23090" PostTypeId="2" ParentId="23089" CreationDate="2021-11-05T10:37:00.907" Score="13" Body="&lt;h1&gt;Full scale climate models&lt;/h1&gt;&#xA;&lt;p&gt;The atmospheric climate simulations that are presented in the IPCC reports are performed by quite large and complex models. Running these models needs a &amp;quot;&lt;em&gt;supercomputer&lt;/em&gt;&amp;quot; (high performance cluster). Additionally, certain &amp;quot;&lt;em&gt;forcing data&lt;/em&gt;&amp;quot; and &amp;quot;&lt;em&gt;boundary conditions&lt;/em&gt;&amp;quot; are needed.&lt;/p&gt;&#xA;&lt;p&gt;Boundary conditions are the top of the atmosphere and the Earth's surface/oceans. Partly, atmospheric climate model simulations are directly coupled to ocean model simulations. This makes the models even larger and harder to setup/run. &amp;quot;Forcing data&amp;quot; means thinks like CO&lt;sub&gt;2&lt;/sub&gt; emissions, emissions of particulate matter, solar radiation ... .&lt;/p&gt;&#xA;&lt;p&gt;Having said that: it is quite unrealistic to setup und run a &amp;quot;real&amp;quot; climate model just for fun.&lt;/p&gt;&#xA;&lt;h1&gt;Further reading on recent climate modeling activities&lt;/h1&gt;&#xA;&lt;p&gt;Simulation results of the &lt;em&gt;couple model intercomparison project&lt;/em&gt; (CMIP) form the basis for the IPCC reports. The CMIP Phase 6 (CMIP6) simulations form the basis of the most recent IPCC reports. There is an overview paper of CMIP6 which might indicate how large the overhead for running &amp;quot;real&amp;quot; climate models in a comparable way is &lt;a href=&quot;https://doi.org/10.5194/gmd-9-1937-2016&quot; rel=&quot;noreferrer&quot;&gt;(Eyring et al., 2016)&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;One of the models that were used for the CMIP5 and CMIP6 simuations was the MPI-ESM model. An overview of this model is given in &lt;a href=&quot;https://doi.org/10.1002/jame.20038&quot; rel=&quot;noreferrer&quot;&gt;Giorgette et al. (2013)&lt;/a&gt;. Detailed descriptions are available in this &lt;a href=&quot;http://agupubs.onlinelibrary.wiley.com/hub/issue/10.1002/(ISSN)1942-2466.MPIESM1/&quot; rel=&quot;noreferrer&quot;&gt;special issue&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;There are several more models used in CMIP5 and CMIP6. The MPI-ESM is just an example.&lt;/p&gt;&#xA;&lt;h1&gt;Climate models made for training&lt;/h1&gt;&#xA;&lt;p&gt;There are some simple climate models that are made for students and which are based on a few governing equations. Seems models show the general features of climate models but can be run on a normal end-user computer. One of these models is the &amp;quot;Monash simple climate model&amp;quot;. An instance of that model which can be run via a web-GUI is available &lt;a href=&quot;http://mscm.dkrz.de/overview_i18n.html?locale=EN&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;. There is a &lt;a href=&quot;http://mscm.dkrz.de/GREB_model.html?locale=EN&quot; rel=&quot;noreferrer&quot;&gt;documentation available&lt;/a&gt; in which you will find links to a publication describing the model and to a repository to download the source code.&lt;/p&gt;&#xA;&lt;p&gt;There is another climate model made for training which is called &lt;a href=&quot;https://www.mi.uni-hamburg.de/en/arbeitsgruppen/theoretische-meteorologie/modelle/plasim.html&quot; rel=&quot;noreferrer&quot;&gt;Planet Simulator&lt;/a&gt;. Download details and documentation are offered on that web page.&lt;/p&gt;&#xA;" OwnerUserId="5594" LastEditorUserId="2470" LastEditDate="2021-11-05T11:04:28.293" LastActivityDate="2021-11-05T11:04:28.293" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23091" PostTypeId="1" CreationDate="2021-11-05T12:26:26.877" Score="3" ViewCount="52" Body="&lt;p&gt;I am currently setting up a wind-wave model for which I need to input the wind forcing for the whole domain.&lt;/p&gt;&#xA;&lt;p&gt;I have obtained the wind speed and direction from two sources: CFSv2 and ERA5. Unfortunately, I found some discrepancies between the two datasets.&lt;/p&gt;&#xA;&lt;p&gt;To select the most suitable dataset for my case I am trying to compare the datasets values to the field measurement. So, Where I can find wind measurements from weather stations online?&lt;/p&gt;&#xA;&lt;p&gt;I am interested in the Mediterranean zone and I need the hourly data.&lt;/p&gt;&#xA;" OwnerUserId="12479" LastActivityDate="2021-11-05T13:03:28.677" Title="Weather station data" Tags="|wind|open-data|field-measurements|weatherdata|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23092" PostTypeId="2" ParentId="23086" CreationDate="2021-11-05T12:54:18.673" Score="0" Body="&lt;p&gt;The process is a &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Ice%E2%80%93albedo_feedback&quot; rel=&quot;nofollow noreferrer&quot;&gt;positive feedback&lt;/a&gt;: Global warming, as a result of the anthropogenic enhancement of the atmospheric greenhouse effect, leads to loss of ice on planetary surfaces which decreases the planetary albedo (Earth becomes &amp;quot;less white&amp;quot;). This results in less solar radiation reflected back to space, and this further enhances global warming, thus accelerating ice melting, and so on.&lt;/p&gt;&#xA;" OwnerUserId="24481" LastActivityDate="2021-11-05T12:54:18.673" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23093" PostTypeId="2" ParentId="23091" CreationDate="2021-11-05T13:03:28.677" Score="2" Body="&lt;p&gt;If you are trying to do a model skill assessment, then the best way is to try to use observations that have a similar footprint to the model. I would recommend you try remote sensed data. A good place to begin is &lt;a href=&quot;https://www.remss.com/measurements/wind/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. If you are looking for observations at a point in the Mediterranean, you can try in Copernicus. If you are a registered user of ECMWF products, you can the &lt;a href=&quot;https://apps.ecmwf.int/mars-catalogue/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Meteorological Archival and Retrieval System (MARS)&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2021-11-05T13:03:28.677" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23094" PostTypeId="1" AcceptedAnswerId="23097" CreationDate="2021-11-05T13:04:04.163" Score="5" ViewCount="156" Body="&lt;p&gt;This is a question on methodology. But I have 4d temperature and salinity gridded data (time, depth, lat and lon). The time is in monthly time steps.&#xA;How would I get the annual harmonics of temperature and salinity using a periodicity of 12 months:&lt;/p&gt;&#xA;&lt;p&gt;The equation is:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ Var(t,z,y,x) = A (z,y,x) * \cos [ (2 \pi t/P + \phi(z,y,x)] $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; is the amplitudes of the annual component, where &lt;span class=&quot;math-container&quot;&gt;$var$&lt;/span&gt; is either temp or salinity. &lt;span class=&quot;math-container&quot;&gt;$\phi$&lt;/span&gt; is the phase angle which determine the time when the maximum of the annual harmonic occurs. And &lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt; varies from 0 - n months (however long the time series is).&lt;/p&gt;&#xA;&lt;p&gt;We can isolate &lt;span class=&quot;math-container&quot;&gt;$A(z,y,x)$&lt;/span&gt; just with algebra, but the issue is finding the phase angle where the maximum of the annual harmonic occurs.&lt;/p&gt;&#xA;&lt;p&gt;Do you you need to take a fourier transform of monthly means (January - December), or do you take the FT of the entire time series but just look at the power spectrum at 12 months...&#xA;I am using Python, and taking the fourier transform is no problem. I just don't know how to treat the data to obtain the phase angle where the maximum of the annual harmonic occurs.&#xA;What might be the steps to find the annual harmonic amplitude given 4D temp and salinity (time in months, depth, lat and lon)?&lt;/p&gt;&#xA;" OwnerUserId="24625" LastActivityDate="2021-11-05T15:52:04.353" Title="How to determine the annual harmonics of temperature and salinity data?" Tags="|oceanography|temperature|salinity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23095" PostTypeId="2" ParentId="23076" CreationDate="2021-11-05T14:44:18.120" Score="1" Body="&lt;p&gt;I guess you'll mostly get opinions here, which means your question is probably not the greatest fit for Stack Exchange, but FWIW here's my opinion, take it or leave it.&lt;/p&gt;&#xA;&lt;p&gt;You may have thought about this already, but fair and useful quizzes have features including:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;They mainly ask about important things, to check the big concepts. A student might know that augite is a pyroxene, for example, or that pyroxenes and amphiboles are related families of silicates, but I wouldn't expect many to know that augite is an inosilicate. That just feels like something I can look up in a book if I ever need to know it.&lt;/li&gt;&#xA;&lt;li&gt;Tricky concepts are tested several times by asking various different questions about the same ideas.&lt;/li&gt;&#xA;&lt;li&gt;Start with easier questions, end with harder ones.&lt;/li&gt;&#xA;&lt;li&gt;The answer alternatives must reflect the kinds of mistakes students typically make.&lt;/li&gt;&#xA;&lt;li&gt;Correct answers are backed up or reinforced, and incorrect answers are explained.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Some thoughts about what this means for your app:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Generating random questions from SQL queries will not, by itself, produce a fair or useful quiz.&lt;/li&gt;&#xA;&lt;li&gt;Maybe you should add a field like 'knowledge level' with values like 'beginner' and 'expert' to your database. Then you can ask beginners about quartz and gold, and experts about aegerine and spessartine.&lt;/li&gt;&#xA;&lt;li&gt;Use fields like TYPE to form simplified super-groups, like 'silicates'. Then, for instance, you can ask about silicates vs non-silicates early on, and narrow down to different families of silicates later on, or in a harder quiz.&lt;/li&gt;&#xA;&lt;li&gt;Knowing a few formulas, or looking for SiO2 in a silicate, is a reasonable expectation. So you could ask about forumlas, but only when the formula is less than a few characters long (say).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;You should also know that the spellings 'pirope' (pyrope), 'calcosine' (chalcosine) and 'sillicate' (silicate) are not standard. I'm not an expert; maybe they are legitimate variants, but I don't remember seeing them before. And I wouldn't call gold a 'non-silicate', because it's also a non-oxide and a non-carbonate; it's a metal.&lt;/p&gt;&#xA;&lt;p&gt;Last thing: pictures feel like a must-have for this app.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2021-11-05T14:44:18.120" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23096" PostTypeId="2" ParentId="23086" CreationDate="2021-11-05T15:14:32.300" Score="6" Body="&lt;p&gt;The answers so far focus on feedback effects. But to my mind, those do not explain the phenomenon on their own, because there needs to be some warming signal to feed back, if you see what I mean.&lt;/p&gt;&#xA;&lt;p&gt;I think there are a few first-order contributors, including:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Ice is not a perfect reflector, so the sun warms the ice up a bit. Almost all reflectors absorb net radiation like this.&lt;/li&gt;&#xA;&lt;li&gt;The atmosphere is not perfectly transparent, so some of the reflected light is scattered and trapped in the atmosphere.&lt;/li&gt;&#xA;&lt;li&gt;The Arctic's climate is not a closed system, so for example it is subject to atmospheric conditions across the northern hemisphere and eventually the globe.&lt;/li&gt;&#xA;&lt;li&gt;The Arctic ice-cap floats entirely on the Arctic ocean, which is not a closed system either, so it is affected by the temperature of the world ocean. (And water has a large specific heat capacity, so it's a very effective carrier of heat. This is also why rain in Greenland is such a big issue.)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;And for the reasons given by other respondents, all this is made much worse by the various positive feedback effects (which include more than just surface albedo; methane trapped in permafrost is a substantial problem).&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2021-11-05T15:14:32.300" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23097" PostTypeId="2" ParentId="23094" CreationDate="2021-11-05T15:52:04.353" Score="3" Body="&lt;p&gt;With a little bit of math:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$  A * \cos [ (2 \pi t/P + \phi] = a\sin(2\pi t/P)+b\cos(2\pi t/P)$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Then, the amplitude is:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$A=\sqrt{a^2+b^2}$$&lt;/span&gt;&#xA;and the phase is&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\phi=\arctan{\frac{b}{a}}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikibooks.org/wiki/Trigonometry/Simplifying_a_sin(x)_%2B_b_cos(x)&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikibooks.org/wiki/Trigonometry/Simplifying_a_sin(x)_%2B_b_cos(x)&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2021-11-05T15:52:04.353" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23098" PostTypeId="2" ParentId="23086" CreationDate="2021-11-05T16:46:07.323" Score="0" Body="&lt;p&gt;While the Arctic may be 'whiter', it is also immensely sensitive.&lt;/p&gt;&#xA;&lt;p&gt;Some context: during winter, there is an extended snow and ice cover; further, there is less incoming solar radiation during winter due to the axial tilt of the Earth.&lt;/p&gt;&#xA;&lt;p&gt;During summer, snow melt, as well as young ice due to solar radiation increase (it is summer, right). Surfaces become brown, dark, in the tundra and rocky deserts.&lt;/p&gt;&#xA;&lt;p&gt;Ice caps and glaciers are very thick, may loose mass and surface if their mass balance is negative which is usually the case presently. Also older ice (as in perennial or multi-year ice) is more compact and resistant to thawing than young ice, and thus count a lot for the albedo balance in the Arctic.&lt;/p&gt;&#xA;&lt;p&gt;Then what happen is that climate changes are making perennial ice surface-area shrink: so once it is gone, it is gone. For example, the &lt;a href=&quot;https://earthdata.nasa.gov/learn/sensing-our-planet/breakup-of-the-ward-hunt-ice-shelf&quot; rel=&quot;nofollow noreferrer&quot;&gt;breakout of the Ward Hunt Ice Shelf&lt;/a&gt; (this is 83 degrees N):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;An ice island about 1.5 kilometers long, 250 meters wide, and 30 meters thick moves into the Arctic ocean after the fracturing of the Ward Hunt Ice Shelf in August 2002.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;And it is gone.&lt;/p&gt;&#xA;&lt;p&gt;Of course the year after during winter a 1-2 m thick ice cover will form, and in July, will be thawed. So during August, September, the dark, black water of the sea will accumulate heat, warming since the albedo changed from whitish to dark, preventing an eventual restoration of the shelf in the short-to-medium term.&lt;/p&gt;&#xA;&lt;p&gt;See this &lt;a href=&quot;https://climate.nasa.gov/climate_resources/155/video-annual-arctic-sea-ice-minimum-1979-2020-with-area-graph/&quot; rel=&quot;nofollow noreferrer&quot;&gt;video&lt;/a&gt; (NASA) where the 1979-2020 shrink-expand cycle of the sea ice in the Arctic. Old ice is going away, and new ice is not living to the year after. More waves, stronger, during a longer interval since there is less cover means more energy and thus worse conditions for ice to reform.&lt;/p&gt;&#xA;&lt;p&gt;Mid-latitudes to low-latitudes are also warming, but there is no loss of albedo equivalent to polar regions, explaining why the polar regions are sensible in comparison.&lt;/p&gt;&#xA;" OwnerUserId="1411" LastEditorUserId="1411" LastEditDate="2021-11-08T18:36:22.697" LastActivityDate="2021-11-08T18:36:22.697" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23102" PostTypeId="1" AcceptedAnswerId="23103" CreationDate="2021-11-07T03:56:15.793" Score="4" ViewCount="451" Body="&lt;p&gt;How does manure &amp;amp; other organic matter improve soil structure? Based on my understanding, soil structure refers to the arrangement of the aggregates within the soil; a &lt;em&gt;good&lt;/em&gt; soil structure prevents waterlogging, &amp;quot;nutrient-lockup&amp;quot; (and ultimately the death of the crops). However, I don't understand &lt;strong&gt;how&lt;/strong&gt; manure can improve this structure to the benefit of the plants.&lt;/p&gt;&#xA;&lt;p&gt;In my textbook, it has been—without any further explanation—written that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Manure and other &lt;strong&gt;organic matter gives the soil a good structure&lt;/strong&gt; and improves its water-holding properties. Conversely, artificial fertilizers do little to maintain a good soil structure because they contain no organic matter.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Googling led me to the following paragraph, but again, it hardly explains how:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Organic matter causes soil to clump and form soil aggregates&lt;/strong&gt; (how though?), which improves soil structure. With better soil structure, permeability (infiltration of water through the soil) improves, in turn improving the soil's ability to take up and hold water.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;[I have a couple of theories as to how this might be, but I'd rather ask here and not mess up]&lt;/p&gt;&#xA;" OwnerUserId="23287" LastEditorUserId="23287" LastEditDate="2021-11-07T05:54:49.577" LastActivityDate="2021-11-08T05:30:34.597" Title="How does manure &amp; other organic matter improve soil structure?" Tags="|soil|agriculture|human-influence|soil-science|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23103" PostTypeId="2" ParentId="23102" CreationDate="2021-11-07T05:29:02.933" Score="1" Body="&lt;h2&gt;Surface area&lt;/h2&gt;&#xA;&lt;p&gt;Organic material in soil is finely divided and provides a large surface area to mass ratio. Clay particles have a similarly large surface area, but most clays stick to each other because of their micro-structure and chemistry, making soils less permeable and prone to over-compaction.&lt;/p&gt;&#xA;&lt;p&gt;Organic matter, regardless of its ultimate source, is the opposite. Its surface structure keeps the individual particles separated, and its chemistry actively encourages water to infiltrate between, and in fact through, its particles. Well rotted organic matter therefore creates a high reactive surface on which vital soil chemical reactions can take place and opens the structure of the soil column to greater water movement.&lt;/p&gt;&#xA;&lt;p&gt;The surface area created by soil organic matter also hosts soil bacteria and fungi that help to bind soil particles together into larger aggregates, and facilitates semi-permanent chemical binding by creating zones of interaction between water with dissolved minerals and air in the soil.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="6467" LastEditDate="2021-11-07T17:45:21.657" LastActivityDate="2021-11-07T17:45:21.657" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23104" PostTypeId="2" ParentId="21136" CreationDate="2021-11-07T10:06:18.063" Score="4" Body="&lt;p&gt;Parts of Russia might win, but other parts will lose.&lt;/p&gt;&#xA;&lt;p&gt;If you accept what is presented in &lt;a href=&quot;https://www.abc.net.au/news/2021-11-07/a-father-and-son-s-ice-age-plot-to-slow-siberian-thaw/100600570&quot; rel=&quot;nofollow noreferrer&quot;&gt;this news item&lt;/a&gt;, parts of Siberia are already experiencing global warming, with permafrost no longer existent in parts of Yakutia, particularly near Chersky, 130 km south of Russia's Arctic coast.&lt;/p&gt;&#xA;&lt;p&gt;With the loss of permafrost soil develops voids and collapses, with disastrous results for buildings and other infrastructure (pipelines and roads, airports, etc.). According to scientists, the loss of permafrost, due to global warming, &amp;quot;could cost Russia 7 trillion roubles (98.2 billion USD) in damage by 2050 if the rate of warming continues&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-11-07T10:06:18.063" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23105" PostTypeId="1" AcceptedAnswerId="23106" CreationDate="2021-11-07T11:42:05.273" Score="15" ViewCount="4600" Body="&lt;p&gt;It goes without question that salinity levels will be lower where rivers enter as the river water mixing with the sea water will reduce the salinity levels. But, the thing is, when you look at the map below, salinity levels are different in strange places.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4mfwW.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4mfwW.png&quot; alt=&quot;Map of sea surface salinity&quot; /&gt;&lt;/a&gt;&#xA;&lt;sup&gt;Annual mean sea surface salinity for the World Ocean. Data from the &lt;a href=&quot;https://www.nodc.noaa.gov/OC5/WOA09/pr_woa09.html&quot; rel=&quot;noreferrer&quot;&gt;World Ocean Atlas 2009&lt;/a&gt;. &lt;a href=&quot;https://en.wikipedia.org/wiki/Salinity#/media/File:WOA09_sea-surf_SAL_AYool.png&quot; rel=&quot;noreferrer&quot;&gt;Image from Wikipedia&lt;/a&gt; &lt;a href=&quot;https://creativecommons.org/licenses/by-sa/3.0&quot; rel=&quot;noreferrer&quot;&gt;CC BY-SA 3.0&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;The Dead Sea is actually a salt lake, just east of the Mediterranean Sea, so I suppose you can understand the high salinity there. But, why would the salinity be particularly high in the Mediterranean Sea and the Red Sea while particularly low in the Java Sea, Gulf of Thailand, the Andaman Sea, the South China Sea and the Bay of Bengal?  The same anomaly can be seen west of Panama and Colombia.&lt;/p&gt;&#xA;&lt;p&gt;Another part to this question, is that where this map shows &lt;strong&gt;surface&lt;/strong&gt; salinity levels, do the salinity levels level out to a worldwide level as you go deeper or are there different salinity levels worldwide at deeper levels?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Update&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I may have found a possibility why the Red Sea has high salinity, and that is due to desalination plants in the area.&lt;/p&gt;&#xA;&lt;p&gt;The biggest ones are in the United Arab Emirates, Saudi Arabia and Israel. The world's largest desalination plant is located in Saudi Arabia (Ras Al-Khair Power and Desalination Plant) with a capacity of 1,036,000 cubic meters per day. (Source: &lt;a href=&quot;https://www.aquatechtrade.com/news/desalination/worlds-largest-desalination-plants/&quot; rel=&quot;noreferrer&quot;&gt;AquaTechTrade&lt;/a&gt;).  Is that a plausible reason for the Red Sea?&lt;/p&gt;&#xA;" OwnerUserId="21081" LastEditorUserId="111" LastEditDate="2021-11-08T15:36:56.370" LastActivityDate="2021-11-08T15:36:56.370" Title="Why is the sea salinity high in the Mediterannean and Red Sea and low in Indonesia and Malaysia?" Tags="|oceanography|evaporation|salinity|mediterranean|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23106" PostTypeId="2" ParentId="23105" CreationDate="2021-11-07T13:12:07.690" Score="33" Body="&lt;p&gt;It has nothing (or very, very little) to do with desalinization plants. It has to do with the balance between Evaporation minus Precipitation (E-P), rivers, and advection. The link to E-P is the main one:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/siqnz.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/siqnz.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;Source: &lt;a href=&quot;http://www.salinityremotesensing.ifremer.fr/sea-surface-salinity/EmoinsP.png?attredirects=0&quot; rel=&quot;noreferrer&quot;&gt;IFREMER&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Salinity is controlled by processes of concentration and dilution. Evaporation removes water vapor from the sea surface, but the salt remains resulting on an increase in salinity. Meanwhile, precipitation and river runoff flux into the ocean dilutes the salt resulting in lower surface salinities. Taking the difference between evaporation (E) and precipitation (P) provides the net gain or loss of water by the ocean.&lt;/p&gt;&#xA;&lt;p&gt;Sea surface salinity (SSS) patterns are associated with general atmospheric circulation. The net air-sea freshwater fluxes and SSS have patterns that are remarkably similar (Baumgartner and Reichel, 1975; Durack and Wijffels, 2010). The ocean subtropical gyres are at edge of the atmospheric Hadley cells and result in SSS maxima in between 15 and 30 degrees latitude. Rain along the tropics associated with the Intertropical Convergence Zone results in lower SSS close to the Equator. North of the subtropical gyres and in the polar regions, excess precipitation also causes a drop in SSS. Also, there are differences between the Atlantic and Pacific oceans; with the Atlantic having more evaporation that causes a relatively saltier Atlantic basin.&lt;/p&gt;&#xA;&lt;p&gt;The effect of rivers is extremely important on a local or even regional scale, but globally E-P dominates. &lt;a href=&quot;https://i.stack.imgur.com/tHG1U.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tHG1U.jpg&quot; alt=&quot;Water transport&quot; /&gt;&lt;/a&gt; Source: &lt;a href=&quot;https://www2.whoi.edu/site/globalwatercycle/&quot; rel=&quot;noreferrer&quot;&gt;Woods Hole Oceanographic Institution&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;In the cases you mentioned, the Mediterranean Sea and Red Sea have a deficit of precipitation when compare to evaporation. &lt;a href=&quot;https://i.stack.imgur.com/ksaWj.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ksaWj.png&quot; alt=&quot;Mediterranean&quot; /&gt;&lt;/a&gt; Source: &lt;a href=&quot;https://www.salinity-pimep.org/case-studies/high-latitude-and-semi-closed-seas/mediterranean-sea/literature_review.html&quot; rel=&quot;noreferrer&quot;&gt;SMOS&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Even though both of them are connected to the open ocean, the connections are limited (Straits of Gibraltar and Bab al-Mandab Strait) and the currents provide only limited volume exchange. The result is an increased in salinity over the basin especially away from the connection to the open-ocean (higher salinities around the eastern Mediterranean and northern Red Sea).&lt;/p&gt;&#xA;&lt;p&gt;The area around the Bay of Bengal and Indonesia have both increased rain and river discharge resulting in lower salinities.&lt;/p&gt;&#xA;&lt;p&gt;The water volume flux of the largest desalination plants is tiny when compared with the air-sea fluxes over an entire basin or the river discharge of large rivers. If you consider volume flux, the largest desalinization plant in the world (&lt;a href=&quot;https://www.aquatechtrade.com/news/desalination/worlds-largest-desalination-plants/&quot; rel=&quot;noreferrer&quot;&gt;Ras Al Khair, Saudi Arabia&lt;/a&gt;) produces about 12 &lt;span class=&quot;math-container&quot;&gt;$m^3/s$&lt;/span&gt;. Meanwhile, the average river discharge of the Mississippi River is between 7,000–20,000 &lt;span class=&quot;math-container&quot;&gt;$m^3/s$&lt;/span&gt;. In the Mediterranean, river discharge, while smaller than the Mississippi, is still quite large.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/CTsyS.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CTsyS.jpg&quot; alt=&quot;Mediterranean rivers&quot; /&gt;&lt;/a&gt;&#xA;Source: &lt;a href=&quot;https://www.grida.no/resources/5937&quot; rel=&quot;noreferrer&quot;&gt;State of the Mediterranean Marine and Coastal Environment&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Clearly, rivers around the Red Sea have way lower discharges. Another factor to consider is that the brine from desalinization plants is going to tend to sink deeper because of its higher density and it is going to not easily mix with the rest of the water column, not having a large effect on SSS. &lt;a href=&quot;https://eltahir.mit.edu/wp-content/uploads/2019/10/Desalination.pdf&quot; rel=&quot;noreferrer&quot;&gt;Ibrahim and Eltahir (2019)&lt;/a&gt; provides more info on the effect of desalination in the Red Sea.&lt;/p&gt;&#xA;&lt;p&gt;Baumgartner, F. and Reichel, E., 1975. The World Water Balance: Mean Annual Global. Continental and Maritime Precipitation, Evaporation and Runoff (Ordenbourg, München, Germany, 1975).&lt;/p&gt;&#xA;&lt;p&gt;Durack, P.J. and Wijffels, S.E., 2010. Fifty-year trends in global ocean salinities and their relationship to broad-scale warming. Journal of Climate, 23(16), pp.4342-4362.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2021-11-08T15:36:04.377" LastActivityDate="2021-11-08T15:36:04.377" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="23107" PostTypeId="1" CreationDate="2021-11-07T13:48:15.993" Score="2" ViewCount="217" Body="&lt;p&gt;I understand that trace element behavior in a system depends on whether they are compatible or not. But , if that question is asked in an examination , what could be the points that one should write to answer that?&lt;/p&gt;&#xA;" OwnerUserId="24818" LastActivityDate="2021-11-27T11:07:35.893" Title="What is the role of trace elements in magmatic crystallization?" Tags="|geochemistry|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23110" PostTypeId="2" ParentId="23107" CreationDate="2021-11-08T04:31:17.530" Score="3" Body="&lt;p&gt;Not much of anything, trace elements are found in low concentrations in the mantle because they are lithophobic. During crystallisation they end up in the residue of silica, and incompatible elements like gold etc..., that is squeezed out into the country rock around the margins of igneous intrusions.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2021-11-08T04:31:17.530" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23111" PostTypeId="2" ParentId="23102" CreationDate="2021-11-08T05:30:34.597" Score="0" Body="&lt;p&gt;Manure is natural fertilizer.&#xA;Organic material has Carbon in it, also contains proteins, carbs, etc. All the stuff that break down and feed plants over time. Plants don't feed directly but micros and fungi do and break it down to water soluable nutrients.&lt;/p&gt;&#xA;&lt;p&gt;As a structure organic matter retains water, clay and sand are largely wick away water. The organic material properly mixed also fights compaction.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-11-08T05:30:34.597" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23113" PostTypeId="1" AcceptedAnswerId="23118" CreationDate="2021-11-08T22:13:41.217" Score="4" ViewCount="54" Body="&lt;p&gt;It's known that &lt;a href=&quot;https://en.wikipedia.org/wiki/Stream_order&quot; rel=&quot;nofollow noreferrer&quot;&gt;stream orders&lt;/a&gt; are highly regular:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Horton showed that stream order is related to number of streams, channel length, and drainage area by simple geometric relationships; that is, stream order plots against these variables as straight lines on semilogarithmic paper.&lt;/p&gt;&#xA;&lt;p&gt;[...] Among many samples of basins in the United States the bifurcation ratio tends closely to equal 3.5. There are variations, of course. In the examples of basins cited by Horton (1945, p. 290) values of the bifurcation ratio range from 2 to 4.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Fluvial Geomorphology&lt;/em&gt;, p.137&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The stream bifurcation ratio is so regular in any given drainage basin that it's actually remarkable to look at a graph - as in these &lt;a href=&quot;https://www.researchgate.net/figure/Semi-logarithmic-plot-of-the-stream-number-against-stream-orders-for-the-five-sub-basins_fig6_329874358&quot; rel=&quot;nofollow noreferrer&quot;&gt;Indian continent sub-basins&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The process &lt;em&gt;Fluvial Geomorphology&lt;/em&gt; describes for the evolution of these basins involves the random weathering of locally-level surfaces by rain, melt, or less commonly other liquid weathering. Small rivulets form via random depressions in the surface of the earth, which then merge into larger streams of higher order. But this got me thinking...&lt;/p&gt;&#xA;&lt;p&gt;If the emergence of initial rivulets is a random process, shouldn't that random process be biased towards wherever the drainage basin happens to be the most erodible? I'd only expect this kind of macro-level structure to &lt;em&gt;necessarily&lt;/em&gt; emerge if the earth were homogeneous in the drainage basin, but in practice this doesn't seem to need to be required in order for a drainage basin following a regular bifurcation ratio to emerge.&lt;/p&gt;&#xA;&lt;p&gt;My questions are related:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Are there any known criteria for which drainage basins do &lt;em&gt;not&lt;/em&gt; evolve in a way that produces regular stream orders? (When) has this happened?&lt;/li&gt;&#xA;&lt;li&gt;Is my assumption that this macro-level order should only emerge for homogeneous substrate incorrect?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="23031" LastActivityDate="2021-11-10T07:05:51.010" Title="Is initial stream formation in a drainage basin random?" Tags="|rivers|geomorphology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23115" PostTypeId="2" ParentId="9732" CreationDate="2021-11-09T07:54:47.927" Score="1" Body="&lt;p&gt;In spanish:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Mud = &lt;em&gt;barro&lt;/em&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Mudstone = No translation. It would be &lt;em&gt;roca de barro&lt;/em&gt;, but term is &lt;em&gt;barrita&lt;/em&gt; doesn't exist. Mudstone is usually refered to a carbonated mud rock in &lt;a href=&quot;https://en.wikipedia.org/wiki/Dunham_classification&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dunham classification or carbonated rocks&lt;/a&gt;. A mix of silt and clay sized carbonated particles.&lt;/li&gt;&#xA;&lt;li&gt;Mudrock = No translation again.&lt;/li&gt;&#xA;&lt;li&gt;Clay = &lt;em&gt;arcilla&lt;/em&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Claystone = &lt;em&gt;argilita&lt;/em&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Silt = &lt;em&gt;limo&lt;/em&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Siltstone = &lt;em&gt;limolita&lt;/em&gt;. You typed &lt;em&gt;limonita&lt;/em&gt;, that is a compound of oxydes.&lt;/li&gt;&#xA;&lt;li&gt;Shale = &lt;em&gt;lutita&lt;/em&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;They are all term related to the grain size, as you can read in Gary Kindel's answer.&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-11-11T11:33:37.283" LastActivityDate="2021-11-11T11:33:37.283" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23116" PostTypeId="1" CreationDate="2021-11-09T11:57:29.240" Score="3" ViewCount="43" Body="&lt;p&gt;I was once told by a paleontologist that the talus (or astralagus) bone is one of the most frequently observed fossils among mammals.  Can anyone verify if this might be true?&lt;/p&gt;&#xA;&lt;p&gt;Because of the density of the bone I frequently find talus bones as a walking safari guide in Kenya.  I could therefore understand if this bone is over represented in the fossil record.&lt;/p&gt;&#xA;&lt;p&gt;I suppose also though that this is a difficult question to answer since there may not be any analysis of this kind within the scientific literature. At least, I have found none.&lt;/p&gt;&#xA;&lt;p&gt;Here are below a few Talus bones I have found:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UoFeJ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UoFeJ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24615" LastEditorUserId="24615" LastEditDate="2021-11-10T10:11:14.423" LastActivityDate="2021-11-10T10:11:14.423" Title="Is the Talus (or Astralagus) the most frequently recorded fossil mammal bone?" Tags="|paleontology|fossils|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23117" PostTypeId="2" ParentId="7464" CreationDate="2021-11-09T22:22:23.550" Score="0" Body="&lt;p&gt;I believe the phrase &lt;em&gt;specific words  have specific meaning&lt;/em&gt; is pertinent here. I believe the question has been misunderstood in the answers as pertaining to daylight instead of daytime. This question is not referring to daylight hours, it is in reference to the fact that the sidereal day length varies by plus or minus ~4 minutes due to a few factors; asynchronous rotation of earth, earth's tilted axis, variable speed at para/aphelion positions, and elliptical orbit being the primary factors. The 24hr day we all use is the sidereal mean time or standard time.&lt;/p&gt;&#xA;&lt;p&gt;It is an interesting question. I cannot purport that the following is absolutely a fact but would say that it is a reasonable presumption with high confidence.&lt;/p&gt;&#xA;&lt;p&gt;It would likely be between the 23.5 degree latitudes known as the tropic of Cancer and Capricorn. I might even make the assumption that you would have to be one that latitude in conjunction with the corresponding equinox or solstice. Those assumptions are hesitant at best though. The lack of data published makes me consider that the interactions of celestial bodies in asynchronous and non tidally locked orbits, while also wobbling on axis may continually affect what days and latitudes the amount of time from apex to apex of the sun to be exactly 24 hrs.&lt;/p&gt;&#xA;" OwnerUserId="24833" LastActivityDate="2021-11-09T22:22:23.550" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23118" PostTypeId="2" ParentId="23113" CreationDate="2021-11-10T07:05:51.010" Score="1" Body="&lt;p&gt;There are what are called &amp;quot;structure driven&amp;quot; stream courses, these occur where the formations underlying the stream bed have a large impact on the fluvial forms in the drainage basin. This is most common where the substrate has been fractured by tectonic motion or where there are inconsistencies in unit erodibility in bedded formations. These conditions force streambeds to follow lines of weakness that inhibit many &amp;quot;normal&amp;quot; behaviours such as bifurcation rates.&lt;/p&gt;&#xA;&lt;p&gt;You can also get direct tectonic effects on the paths of streambeds where they cross faultlines. This can be in the form of damming, ponding, and overflow episodes after earthquakes. Waterfalls across surface faults are not uncommon. Nor are gorges where a river has cut across a fault driven orographic zone. One can also see &amp;quot;kinked&amp;quot; river beds where a river flowing across a faultline is bent by movement along the fault, in this case the river will follow the line of the fault for some distance before regaining the bed that has been displaced by it's motion.&lt;/p&gt;&#xA;&lt;p&gt;I hope that answers your question but hit me up in the comments if you want more.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2021-11-10T07:05:51.010" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23119" PostTypeId="1" AcceptedAnswerId="23121" CreationDate="2021-11-10T09:20:48.190" Score="2" ViewCount="106" Body="&lt;p&gt;Acording to &lt;a href=&quot;https://www.britannica.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;britanica.com&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;sedimentary rock&lt;/strong&gt;, rock formed at or near Earth’s surface by the accumulation and lithification of sediment (detrital rock) or by the&#xA;precipitation from solution at normal surface temperatures (chemical&#xA;rock).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;My question is, as carbonated deposits on caves are formed by chemical precipitation, does that mean a deposit of stalactites is a sedimentary deposit?&lt;/p&gt;&#xA;&lt;p&gt;Or perhaps it is a supergenic deposit?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-11-10T09:34:20.187" LastActivityDate="2021-11-10T12:56:38.147" Title="Are carbonated stalactite deposits sedimentary deposits?" Tags="|geology|precipitation|sedimentology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23121" PostTypeId="2" ParentId="23119" CreationDate="2021-11-10T12:56:38.147" Score="3" Body="&lt;p&gt;Stalactites are sedimentary deposits though they form by supergenic-like processes. Importantly, the layers within contain historical information about environmental surface conditions. By contrast, a supergenic deposit is the result of remineralization and concentration of one mineral into another, different mineral; more ultra low-grade chemical metamorphism than sedimentary.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2021-11-10T12:56:38.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23122" PostTypeId="1" AcceptedAnswerId="23181" CreationDate="2021-11-10T14:46:57.863" Score="1" ViewCount="79" Body="&lt;p&gt;Coming from &lt;a href=&quot;https://earthscience.stackexchange.com/a/18172/20559&quot;&gt;this question and the answer&lt;/a&gt;, a proposed genetic classification of minerals:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Endogenic: Magmatic, Metamorphic, Hydrothermal.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Exogenic: Supergene, Sedimentary.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;My question is how would you describe minerals as chrysotile formed as an alteration product of mafic rocks in surface (weathering), or clays or oxydes formed in soils as diaspore, that forms in bauxites.&lt;/p&gt;&#xA;&lt;p&gt;Could an alteration or weathering class be added to that classification?&lt;/p&gt;&#xA;&lt;p&gt;From &lt;a href=&quot;https://earthscience.stackexchange.com/a/23121/20559&quot;&gt;this other answer&lt;/a&gt; I would tend to say they can't be supergenic, but they are exogenic.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;By contrast, a supergenic deposit is the result of remineralization and concentration of one mineral into another, different mineral; more ultra low-grade chemical metamorphism than sedimentary.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Perhaps as a mineral resulted from weathering, it should be included in sedimentary environment because weathering is a part of sedimentary cycle?&lt;/p&gt;&#xA;&lt;p&gt;What is better?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Diaspore:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Sedimentary&lt;/strong&gt;: bauxites.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Weathering&lt;/strong&gt;: bauxites.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Alteration&lt;/strong&gt;: bauxites.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Supergenic&lt;/strong&gt;: bauxites.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerDisplayName="user20559" LastEditorDisplayName="user20559" LastEditDate="2021-11-18T08:39:08.017" LastActivityDate="2021-11-20T18:31:36.377" Title="How to genetically classify a weathering mineral or a mineral formed in soil?" Tags="|geology|mineralogy|minerals|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23123" PostTypeId="1" AcceptedAnswerId="23124" CreationDate="2021-11-10T16:03:46.610" Score="1" ViewCount="54" Body="&lt;p&gt;I am trying to download climate projection data and am only interested in the surface temperature, radiation, etc.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://cds.climate.copernicus.eu/cdsapp#!/dataset/projections-cmip6?tab=overview&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://cds.climate.copernicus.eu/cdsapp#!/dataset/projections-cmip6?tab=overview&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The vertical coverage is Single levels or pressure levels (1 - 1000 hPa). Which one represents values at the surface, say between 1-20 meters above the ground?&lt;/p&gt;&#xA;" OwnerUserId="3061" LastActivityDate="2021-11-11T01:18:39.077" Title="Do pressure levels correspond to elevation?" Tags="|weatherdata|climate-data|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23124" PostTypeId="2" ParentId="23123" CreationDate="2021-11-11T01:18:39.077" Score="5" Body="&lt;p&gt;You can download the near surface features explicitly (click &amp;quot;Single levels&amp;quot; radio button). Then select each variable that has &amp;quot;near surface&amp;quot; or &amp;quot;surface,&amp;quot; in the name or is intuitively a surface property (such as sea level pressure).&lt;/p&gt;&#xA;&lt;p&gt;For your own edification, pressure levels decrease with height. The 1000 hPa level corresponds with the ocean surface. This would be fine, but things like mountains, &lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Everest#Meteorology&quot; rel=&quot;noreferrer&quot;&gt;where the pressure can be significantly smaller&lt;/a&gt;, obscure the field.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-11-11T01:18:39.077" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23126" PostTypeId="1" CreationDate="2021-11-11T04:27:53.203" Score="4" ViewCount="162" Body="&lt;p&gt;I have a WRF-chem output with NO&lt;sub&gt;2&lt;/sub&gt; mixing ratio for 37 levels, for my analysis I need to convert it into into column density. How do I do that?&lt;/p&gt;&#xA;" OwnerUserId="24841" LastEditorDisplayName="user20559" LastEditDate="2021-11-11T09:50:17.897" LastActivityDate="2021-11-11T09:50:17.897" Title="How to convert $\ce{NO2}$ mixing ratio (ppmv) into $\ce{NO2}$ column density(moles/m2)?" Tags="|meteorology|atmosphere|atmosphere-modelling|atmospheric-chemistry|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23127" PostTypeId="1" CreationDate="2021-11-11T06:24:46.503" Score="1" ViewCount="390" Body="&lt;p&gt;Is it possible that increased CO&lt;sub&gt;2&lt;/sub&gt; levels during the larger dinosaurs era is a major factor in why dinosaurs grew so big during this period?&lt;/p&gt;&#xA;&lt;p&gt;And extrapolating this question, is it possible that the increased CO&lt;sub&gt;2&lt;/sub&gt; during the industrial revolution has contributed to each generation of man growing bigger?&lt;/p&gt;&#xA;" OwnerUserId="24806" LastEditorDisplayName="user20559" LastEditDate="2021-11-11T09:49:33.787" LastActivityDate="2021-12-28T16:56:06.583" Title="Could increased $\ce{CO2}$ levels be a contributing factor why dinosaurs grew so big?" Tags="|atmosphere|co2|mesozoic|" AnswerCount="3" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23128" PostTypeId="2" ParentId="23127" CreationDate="2021-11-11T08:03:23.813" Score="-2" Body="&lt;p&gt;Climate made the dinosaurs big. Studies of air bubbles trapped in various samples of amber show that the atmosphere of the Cretaceous may have had up to 35 per cent oxygen, compared to only about 21% today. Dinosaurs first appeared during the Triassic when there was lower oxygen so early dinosaurs were small; therefore developed highly efficiency breathing that allowed them to survive. All the while many species became extinct. The Triassic-Jurassic extinction event killed more than half the species, including several mammals and mammal-like reptiles (Synapsids) but allowed new dinosaurs of filling niche. CO2 levels were in the 1000-2000 ppm ratio so it fed a Huge ecosystem of vegetation. CLimate was relatively warm, so much so metabolism was devoted to growth than temperature moderation.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-11-11T08:03:23.813" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23130" PostTypeId="1" CreationDate="2021-11-11T13:28:24.797" Score="4" ViewCount="39" Body="&lt;p&gt;I am working with a global fully distributed (gridded) hydrological model and I am having some issues regarding two sets of data extremely important for the correct representation of the soil evaporation and evapotranspiration processes: Leaf Area Index (LAI) and Soil Depth (rooting and total).&lt;/p&gt;&#xA;&lt;p&gt;As I'm not an expert in neither of these two thematic areas, my perplexities regards both the quality of the source data and how the data should be unmixed basing on land use classes: as for instance forest, irrigated crops, and (rainfed) shrubland.&lt;/p&gt;&#xA;&lt;p&gt;I was wondering whether you could point to some good reference datasets and some unmixing methodology that you found particularly useful in your experience.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;EDIT&lt;/strong&gt;- just to clarify why the unmixing is needed: the observed (remotely sensed) LAI is usually made available at a certain spatial resolution (good products are offered in the order of magnitude of few hundred meters or 1 km), and these territorial units are characterized by different land use classes. Having a correct representation of the LAI and soil depth for the specific cell and the specific land use class is crucial to analyze the change in the hydrological process associated to a dynamic land use change throughout the simulations.&lt;/p&gt;&#xA;" OwnerUserId="8087" LastEditorUserId="8087" LastEditDate="2021-11-11T13:36:14.147" LastActivityDate="2021-11-15T08:36:07.467" Title="Global gridded Leaf Area Index and Soil Depth data for hydrological analysis - references and unmixing by land use" Tags="|hydrology|soil|soil-moisture|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23132" PostTypeId="1" AcceptedAnswerId="23525" CreationDate="2021-11-12T00:10:29.503" Score="6" ViewCount="229" Body="&lt;p&gt;From Science News' &lt;a href=&quot;https://www.sciencenews.org/article/mineral-diamond-davemaoite-earth-mantle-heat&quot; rel=&quot;noreferrer&quot;&gt;A mineral found in a diamond’s flaws contains the source of some of Earth’s heat&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A tiny bit of rock trapped inside a diamond is now opening a brand-new window into what the planet’s lower mantle looks like. Inside the diamond is a &lt;a href=&quot;https://www.sciencenews.org/article/mineral-diamond-davemaoite-earth-mantle-heat#:%7E:text=newly%20identified%20silicate%20mineral%20dubbed%20davemaoite&quot; rel=&quot;noreferrer&quot;&gt;newly identified silicate mineral dubbed davemaoite&lt;/a&gt; that can only have formed in Earth’s lower mantle, researchers report November 12 in Science. It’s the first time that scientists have managed to definitively prove that this type of lower mantle mineral — previously just predicted from laboratory experiments — actually exists in nature. The team &lt;a href=&quot;https://www.sciencenews.org/article/flaws-make-it-geologists-best-friend&quot; rel=&quot;noreferrer&quot;&gt;named the mineral&lt;/a&gt; for well-known experimental high-pressure geophysicist Ho-kwang (Dave) Mao (SN: 3/16/04)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Scientists had previously estimated that about 5 percent to 7 percent of the lower mantle must be made up of this mineral, Tschauner says. But it’s fiendishly difficult to directly observe such deep-Earth minerals. That’s because minerals that are stable in the intense pressures of the lower mantle — which extends all the way to 2,700 kilometers below Earth’s surface — &lt;strong&gt;begin to rearrange their crystal structures as soon as the pressure lets up.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Even the planet’s most common mineral, &lt;a href=&quot;https://www.sciencenews.org/article/earths-most-abundant-mineral-finally-has-name&quot; rel=&quot;noreferrer&quot;&gt;a lower mantle magnesium iron silicate known as bridgmanite&lt;/a&gt;, was largely theoretical until 2014, when it was discovered to have naturally occurred within a meteorite that had slammed into Australia with a force that generated crushing, deep mantle-like pressures in the rock (SN: 11/27/14). To date, bridgmanite is the only other high-pressure silicate mineral confirmed to exist in nature.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Diamonds act like time capsules, locking in the original mineral forms on their journey to the surface.&lt;/strong&gt; The discovery of davemaoite is not only a confirmation of its existence, but it also reveals the location of some sources of heat deep inside Earth.... By identifying the chemical makeup of davemaoite, researchers can now confirm where those elements reside.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;That’s because the Botswana diamond also contained &lt;a href=&quot;https://www.sciencenews.org/article/diamonds-reveal-sign-deepest-water-known-inside-earth&quot; rel=&quot;noreferrer&quot;&gt;a high-pressure form of ice&lt;/a&gt; as well as another high-pressure mineral known as wüstite (SN: 3/8/18). The presence of those inclusions helped narrow down the rough pressures at which the davemaoite might have formed: somewhere between 24 billion pascals and 35 billion pascals, Tschauner says.&lt;/strong&gt; It’s hard to say exactly what depth that corresponds to, he adds. But the discovery directly links heat generation (the radioactive materials), the water cycle (the ice) and the carbon cycle (represented by the formation of the diamond itself), all in the deep mantle, Tschauner says.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;From the article I think that I'm being told that the diamond is preserving enough pressure to keep both the &amp;quot;davemaoite&amp;quot; and &amp;quot; a high-pressure form of ice&amp;quot; and the wüstite stable as well.&lt;/p&gt;&#xA;&lt;p&gt;Am I understanding this correctly?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; When diamonds &amp;quot;migrate&amp;quot; from deep underground to the surface, do they maintain pressure inside when there is no more pressure outside? If so, how?&lt;/p&gt;&#xA;&lt;p&gt;I would think that as the diamond rises to the surface and the pressure relaxes outside it would relax and expand uniformly and the pressure would relax inside as well. If that's not the case, &lt;em&gt;why not?&lt;/em&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FLbWY.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FLbWY.jpg&quot; alt=&quot;The tiny gray blobs of mineral embedded in this slice of clear diamond are the first samples of newly named davemaoite, a calcium silicate perovskite mineral that only forms in the lower mantle. AARON CELESTIAN/NATURAL HISTORY MUSEUM OF LOS ANGELES COUNTY&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The tiny gray blobs of mineral embedded in this slice of clear diamond are the first samples of newly named davemaoite, a calcium silicate perovskite mineral that only forms in the lower mantle. AARON CELESTIAN/NATURAL HISTORY MUSEUM OF LOS ANGELES COUNTY&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2023-01-23T23:13:10.657" Title="When diamonds &quot;migrate&quot; from deep underground to the surface, do they maintain pressure inside when there is no more pressure outside? If so, how?" Tags="|mantle|crystallography|crystals|pressure|diamond|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23136" PostTypeId="1" CreationDate="2021-11-12T15:55:37.883" Score="2" ViewCount="240" Body="&lt;p&gt;I observed these clouds today (november 12, Belgium) and I was wondering if they could be caused by atmospheric gravity waves. How would you spot the difference between gravity waves and a cloud street consisting of cumulus clouds? I am also looking for a corresponding T-logP (Stüve) diagram. Can you see gravity waves in such a diagram? &lt;a href=&quot;https://i.stack.imgur.com/P7JOm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/P7JOm.jpg&quot; alt=&quot;belgianclouds&quot; /&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/sQJW7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sQJW7.jpg&quot; alt=&quot;belgianclouds2&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22353" LastActivityDate="2021-11-12T15:55:37.883" Title="Atmospheric gravity waves or cumulus cloud street?" Tags="|meteorology|clouds|waves|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23137" PostTypeId="2" ParentId="22590" CreationDate="2021-11-12T20:44:36.783" Score="0" Body="&lt;p&gt;Figure 3a of &lt;a href=&quot;https://esd.copernicus.org/articles/10/729/2019/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Evaluating Climate Emulation: Fundamental Impulse Testing of Simple Climate Models&lt;/a&gt; compares the temperature response of pulses  of CO2 and HC4 (I can't see where they specify the relative quantities).&#xA;&lt;a href=&quot;https://i.stack.imgur.com/E8txw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/E8txw.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2021-11-12T20:44:36.783" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23138" PostTypeId="1" CreationDate="2021-11-12T23:18:30.463" Score="4" ViewCount="732" Body="&lt;p&gt;Just as Ozone concentration peaks at around 20 km in the stratosphere, having a distribution around higher and lowers layers of the atmosphere, does the same happen for carbon dioxide or other greenhouse gases?&lt;/p&gt;&#xA;" OwnerUserId="24416" LastActivityDate="2021-11-14T18:43:30.277" Title="Does carbon dioxide preferentially accumulate in one layer of the atmosphere?" Tags="|climate-change|atmosphere|atmospheric-chemistry|greenhouse-gases|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23139" PostTypeId="1" CreationDate="2021-11-12T23:24:30.780" Score="4" ViewCount="549" Body="&lt;p&gt;We know all about how the Earth's temperature needs to stay below &amp;quot;1.5° above pre-industrial levels&amp;quot;. But what were they?&lt;/p&gt;&#xA;&lt;p&gt;Every news article and policy statement seems to hand-wave it away. Graphs put the 1880 temperature at zero. But 1880 was not zero, it had a temperature. And so does today. And so will tomorrow. What was it? What is it? What will we need it to be?&lt;/p&gt;&#xA;&lt;p&gt;I'm not asking for just a methodology or an abstraction here. I want a number.&lt;/p&gt;&#xA;" OwnerUserId="24853" LastActivityDate="2021-11-13T04:19:50.313" Title="1.5° above what?" Tags="|climate-change|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23140" PostTypeId="1" AcceptedAnswerId="23155" CreationDate="2021-11-13T00:41:54.663" Score="1" ViewCount="75" Body="&lt;p&gt;How are they holding COP26 if the IPCC hasn't yet completed its latest Assessment Report? I'm reading it at the moment, and more often than not there are descriptions to figures without the figures themselves, for example. I thought COP meetings were supposed to follow new IPCC reports, but AR6 is not finalized to date as I understand it (plus reports from other IPCC working groups). How are world leaders supposed to make drastic decisions regarding greenhouse gas emissions if they don't have all the latest data (they wouldn't make them anyway, I know, but in theory)?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mt8kj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mt8kj.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22632" LastActivityDate="2021-11-14T17:50:11.550" Title="How are they holding COP26 if the IPCC hasn't yet finished the report?" Tags="|climate-change|climate-models|climate-data|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23141" PostTypeId="1" AcceptedAnswerId="23143" CreationDate="2021-11-13T00:52:53.027" Score="4" ViewCount="311" Body="&lt;p&gt;I find the IPCC report hard to read. It's peppered with unexplained terms and is generally cumbersome (no offence to its authors). Here's one example. What is the difference between top-down and bottom-up estimates?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QCRbL.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QCRbL.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22632" LastActivityDate="2021-11-13T01:21:38.117" Title="What is the difference between top-down and bottom-up estimates?" Tags="|climate-change|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23142" PostTypeId="1" CreationDate="2021-11-13T01:13:55.577" Score="4" ViewCount="50" Body="&lt;p&gt;Suppose we say, &amp;quot;We have a climate emergency going on, there's no way we're going to decarbonize our economies fast enough, to hell with biodiversity, we are going to drain the swamps&amp;quot;. What happens then, after implementing such a policy on a global scale? Why is draining wetlands not a good idea, climate-wise? They are responsible for 1/5 of the world's methane emissions, the latest IPCC report says&lt;/p&gt;&#xA;" OwnerUserId="22632" LastEditorUserId="22632" LastEditDate="2021-11-13T21:01:06.397" LastActivityDate="2021-11-13T21:01:06.397" Title="Why is draining wetlands not a good idea, climate-wise?" Tags="|climate-change|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23143" PostTypeId="2" ParentId="23141" CreationDate="2021-11-13T01:15:54.203" Score="8" Body="&lt;p&gt;A bottom-up emissions method is an inventory made by accounting for every known source (or category) and a best-guess estimate for each of their emissions. Bottom-up inventories are often based on government reports which are readily available (no model required) but can sometimes be incomplete or inaccurate.  A top-down method is very different because it is derived from measurements at some location(s) on the Earth. In a top-down method, emissions are inferred from environmental measurements using models that link the relationship between emission rates (from the source) and concentrations measured out in the world.  A top-down estimate is highly dependent on the model/method being used to infer emissions, but can give bottom-up inventories a good gut-check because top-down methods consider real-world conditions.  Top down methods give very poor spatial definition (if any), because most environmental measurements are in select locations or have coarse resolution.  Plus, it is nearly impossible to accurately attribute measurements at one location to all the emissions source locations.  In contrast, bottom-up methods give very good spatial definition.  However, bottom-up inventories are a patchwork that have varied uncertainty and may not be realistic for some particular sectors/locations.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2021-11-13T01:21:38.117" LastActivityDate="2021-11-13T01:21:38.117" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23144" PostTypeId="1" AcceptedAnswerId="23149" CreationDate="2021-11-13T01:44:09.303" Score="5" ViewCount="508" Body="&lt;p&gt;The Keeling curve is very well approximated with an exponential function with an offset &lt;span class=&quot;math-container&quot;&gt;$256$&lt;/span&gt; [ppm]&#xA;&lt;span class=&quot;math-container&quot;&gt;$$256+A\cdot e^{\alpha\cdot t}$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$A=1.095\cdot10^{-12}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\alpha=0.0161$&lt;/span&gt;  (&lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt; is in years b.c.)&lt;/p&gt;&#xA;&lt;p&gt;In the graph below the raw data for the blue sawtooth curve is from &lt;a href=&quot;https://gml.noaa.gov/webdata/ccgg/trends/co2/co2_mm_mlo.txt&quot; rel=&quot;noreferrer&quot;&gt;NOAA&lt;/a&gt;, from the columns 'decimal date' and 'monthly average'.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NDIRV.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NDIRV.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;From the very beginning 1958 the curve has an unbreaked tendency of emissions from fossil fuels and fossil materials and from the sees and the ground. Even the increased global warming the last 50 years must have affected the emissions but still the trend is untouched. How come? Which are the main sources of emissions and why is the trend so stable?&lt;/p&gt;&#xA;&lt;p&gt;To limit the temperature raise below &lt;span class=&quot;math-container&quot;&gt;$1.5-2.0$&lt;/span&gt; °C the pledges from the COP conferences must have an effect on the emissions that is unseen since 1958.&lt;/p&gt;&#xA;" OwnerUserId="16809" LastEditorUserId="16809" LastEditDate="2021-11-13T01:49:10.743" LastActivityDate="2021-11-18T14:49:07.057" Title="How to explain the remarkable regularity of the increased concentration of atmospheric carbon dioxide?" Tags="|climate-change|co2|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23145" PostTypeId="1" AcceptedAnswerId="23733" CreationDate="2021-11-13T04:11:54.080" Score="4" ViewCount="65" Body="&lt;p&gt;As a non-specialist, enviro-enthusiast, I am curious about visualizing post-precipitation run-off in my local area. I have been able to access and download appropriate elevatio rasters for my local topography, but have not been able to find a tool or pipeline to visualize where water goes after it rains. That is, essentially, my goal.&lt;/p&gt;&#xA;&lt;p&gt;I have looked at several packages in this list (&lt;a href=&quot;https://cran.r-project.org/web/views/Hydrology.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://cran.r-project.org/web/views/Hydrology.html&lt;/a&gt;), but no vignettes or examples take me through the process using raster/elevation files.&lt;/p&gt;&#xA;&lt;p&gt;Are there any straightforward walk-throughs that would let me use my existing data to generate visualizations of drainage/flow from preciptation, using previously obtained raster elevation files?&lt;/p&gt;&#xA;" OwnerUserId="24854" LastActivityDate="2022-04-18T18:13:52.797" Title="Easiest way to visualize precipitation drainage using raster elevation files in R?" Tags="|hydrology|precipitation|rainfall|watershed|r|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23146" PostTypeId="2" ParentId="23139" CreationDate="2021-11-13T04:19:50.313" Score="7" Body="&lt;p&gt;According to &lt;a href=&quot;https://www.climate.gov/news-features/understanding-climate/climate-change-global-temperature&quot; rel=&quot;noreferrer&quot;&gt;NOAA&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Averaged across land and ocean, the 2020 surface temperature was 1.76° F (0.98° Celsius) warmer than the twentieth-century average of 57.0°F (13.9°C) and 2.14°F (1.19°C) warmer than the pre-industrial period (1880-1900).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Simply do the math.  The 2020 global surface temperature was 1.76°F warmer than 57.0°F, which is 58.76°F.  This temperature is 2.14°F warmer than the pre-industrial period (1880-1900).  Consequently, the pre-industrial period temperature was 58.76°F - 2.14°F, or approximately 56.62°F (13.68°C).&lt;/p&gt;&#xA;" OwnerUserId="24855" LastActivityDate="2021-11-13T04:19:50.313" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23147" PostTypeId="1" AcceptedAnswerId="23151" CreationDate="2021-11-13T11:10:24.770" Score="1" ViewCount="61" Body="&lt;p&gt;&lt;a href=&quot;https://www.sciencenews.org/article/earth-lower-atmosphere-rising-climate-change-troposphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth’s lower atmosphere is rising due to climate change&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Temperature is the driving force behind this change, says Jane Liu, an environmental scientist at the University of Toronto. The troposphere varies in height around the world, reaching as high as 20 kilometers in the tropics and as low as seven kilometers near the poles. During the year, the upper boundary of the troposphere — called the tropopause — naturally rises and falls with the seasons as air expands in the heat and contracts in the cold. But as greenhouse gases trap more and more heat in the atmosphere, the troposphere is expanding higher into the atmosphere&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Why do the lowest gases on earth descend? Didn't that always happen? Is there any physical explanation or an article about this?&lt;/p&gt;&#xA;" OwnerUserId="22798" LastActivityDate="2021-11-14T00:38:11.663" Title="Gases descending from atmospheres" Tags="|meteorology|atmosphere|terminology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23148" PostTypeId="1" AcceptedAnswerId="23163" CreationDate="2021-11-13T21:33:31.353" Score="5" ViewCount="280" Body="&lt;p&gt;My daughter found this fossil while walking through the &lt;a href=&quot;https://en.wikipedia.org/wiki/Swabian_Jura&quot; rel=&quot;nofollow noreferrer&quot;&gt;Swabian Jura&lt;/a&gt;, in Southern Germany.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YZOAv.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YZOAv.jpg&quot; alt=&quot;fossil + crystal&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;She asked me about it, but I have absolutely 0 clue about geology.&#xA;The crystal part is 3cm in diameter, but there's a brighter region around it, which might also belong to the fossil, and is 6.5cm in diameter.&lt;/p&gt;&#xA;&lt;p&gt;Is it an &lt;a href=&quot;https://en.wikipedia.org/wiki/Ammonoidea&quot; rel=&quot;nofollow noreferrer&quot;&gt;ammonite&lt;/a&gt;? How old could it be? Is it really some kind of crystal, is it some salt?&lt;/p&gt;&#xA;&lt;p&gt;I'd be happy to give my daughter any info. All I've got until now is &amp;quot;That's a beautiful fossil&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Here are some more details:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WC3GU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WC3GU.jpg&quot; alt=&quot;detail&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Does this also belong to the fossil?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/aXZey.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aXZey.jpg&quot; alt=&quot;detail&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vTyC8.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vTyC8.jpg&quot; alt=&quot;details&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12617" LastEditorDisplayName="user20559" LastEditDate="2021-11-14T08:59:17.537" LastActivityDate="2021-11-16T21:36:56.583" Title="What is this fossil? What is this crystal?" Tags="|fossils|paleontology|crystals|identification-request|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23149" PostTypeId="2" ParentId="23144" CreationDate="2021-11-13T22:36:30.000" Score="5" Body="&lt;p&gt;The Keeling Curve - the measured growth of atmospheric CO&lt;sub&gt;2&lt;/sub&gt; - appears directly related to global economic growth over the relevant period. This is because such growth has been highly dependent on growth of fossil fuel burning.&lt;/p&gt;&#xA;&lt;p&gt;Attempts to sustain economic growth without increasing fossil fuel use and to reduce existing dependence are a recent phenomena, with a lot of resistance within the economic sectors that produce and use them to any constraints on their future use; growth of their use still continues. Whilst new energy generation is now predominately &amp;quot;renewables&amp;quot; (wind and solar), exceeding the growth of fossil fuels and presumed to be reducing the rate of that growth we have still not reached the point where fossil fuel use stops growing.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;an unbroken tendency of emissions from fossil fuels and fossil&#xA;materials and from the sees and the ground.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Seas and vegetation are taking up (not adding) some of the excess atmospheric CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&lt;p&gt;This diagram shows The Global Carbon Cycle -&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cSjkV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cSjkV.jpg&quot; alt=&quot;Global Carbon Cycle&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="2470" LastEditDate="2021-11-14T11:32:53.207" LastActivityDate="2021-11-14T11:32:53.207" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23151" PostTypeId="2" ParentId="23147" CreationDate="2021-11-14T00:38:11.663" Score="4" Body="&lt;p&gt;I think, as David Hanmen alluded to, you have misread the article.&lt;/p&gt;&#xA;&lt;p&gt;In laymen's terms (though not fully technically accurate), it describes that the height of the ozone layer should increase as the earth warms.&lt;/p&gt;&#xA;&lt;p&gt;Think about it this way- when matter warms, it (generally) expands. This also applies to the atmosphere. When the atmosphere warms, it expands... upward. So the ozone layer is much further from the ground in the tropics where it is warm, than near the poles where it is cold.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-11-14T00:38:11.663" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23152" PostTypeId="2" ParentId="23138" CreationDate="2021-11-14T01:07:25.057" Score="2" Body="&lt;p&gt;They do, but not to the extreme that &lt;span class=&quot;math-container&quot;&gt;$\ce{O3}$&lt;/span&gt; does. For reference, there is &lt;span class=&quot;math-container&quot;&gt;$\ce{O3}$&lt;/span&gt; near the ground, but the &lt;span class=&quot;math-container&quot;&gt;$\ce{O3}$&lt;/span&gt; in the stratosphere is amplified by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ozone%E2%80%93oxygen_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chapman cycle&lt;/a&gt; that forms it.&lt;/p&gt;&#xA;&lt;p&gt;Generally, greenhouse gases have the highest concentration in layers where they are generated. Let's think about a few (not all) of the greenhouse gases, their sources, and some relevant processes that keep them confined to their layer.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; - emitted by combustion and respiration. Because &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; is a mostly stable molecule, it can probably travel pretty high into the atmosphere before it falls down due to the molecular weight. But due to where it's generated it'd still be more concentrated near the ground.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Water vapor (yes, it is a greenhouse gas) - most prominent in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Surface_layer&quot; rel=&quot;nofollow noreferrer&quot;&gt;surface layer&lt;/a&gt;, but generally decreases with height. Generally caps out due to phase transition (it becomes liquid water and ice), but some can enter into the stratosphere.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Methane - agricultural and biological sources. Like water, it is most prominent in the surface layer. However, it isn't as bound by phase transition as water vapor is.  It does interact with other chemicals in the atmosphere, such as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydroxyl_radical&quot; rel=&quot;nofollow noreferrer&quot;&gt;hydroxyl radical.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="704" LastEditorUserId="6298" LastEditDate="2021-11-14T18:43:30.277" LastActivityDate="2021-11-14T18:43:30.277" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23153" PostTypeId="2" ParentId="23132" CreationDate="2021-11-14T04:30:05.160" Score="4" Body="&lt;p&gt;The question is in regard to pressure confining a rare, deep-mantle formed mineral visible within a diamond inclusion. The pressure on the inclusion within the diamond crystal is really the pressure of confinement within the crystalline lattice of carbon that makes a diamond what it is. Let's digress for a moment.&lt;/p&gt;&#xA;&lt;p&gt;A diamond is a covalent crystal.  Each carbon atom of a diamond crystal is bound to four equidistant carbon atoms tetrahedrally oriented about it, thereby forming a regular tetrahedron with a carbon atom at the center and one at each of four vertices, each atom sharing &lt;em&gt;one&lt;/em&gt; electron in a covalent bond.  This covalent crystal structure renders the diamond crystal as a single molecule.  Among natural minerals, this covalent bonding also renders the diamond as extremely hard. Consequently, the crystalline structure is extraordinarily difficult to dislocate or shear, and will break, or fracture, as a consequence. This characteristic should be compared with the alternate crystalline form of carbon, namely, graphite.  As we all know, graphite is extremely easy to shear and break.  Without graphite, we would be without pencils.&lt;/p&gt;&#xA;&lt;p&gt;Diamond crystals form at extraordinarily high temperatures and pressures deep within the earth's upper mantle.  Nevertheless, the diamond crystal is unstable at temperatures and pressures where graphite is stable.  The crystalline structure of  diamond has unsatisfied bonding abilities on its crystal surface as the crystal-bonding elements there are not surrounded by other covalent bonding units. At the earth's surface, the crystal will reactively degenerate into graphite at a formidably slow rate, but will not readily oxidize unless by forced ignition.   However, these extraordinarily strong covalent bonds result in an extremely high packing density of carbon atoms, and thereby also prevent the crystalline structure from alteration due to pressures existing where the crystal is unstable. &lt;em&gt;Apparently there is little or no alteration in the dimensional stability of the crystalline structure of diamond due to changes in pressure.&lt;/em&gt; In other words, the dimensional stability of diamond is not sensitive to changes in pressure. Diamond cannot be compressed.&lt;/p&gt;&#xA;&lt;p&gt;Inclusions of other minerals within the diamond crystal are rarely formed at the same pressure and temperature conditions under which the diamond was formed. These mineral inclusions are formed some considerable time before formation of the diamond and under conditions even more extreme. An inclusion is simply a formational artifact or otherwise a crystal of some other mineral contained within the diamond crystal.  Inclusions may be typically small. Predominantly formational for gem-quality diamonds, these inclusions are graphite, or otherwise crystalline twinning of the diamond caused by irregularities in the crystal structure as the diamond was formed. But in some rare cases, these inclusions are of crystalline minerals that formed in deep time considerably before formation of the diamond, and at more extreme pressures deep within the mantle.  Such inclusions may predate the formation of the diamond by &lt;em&gt;billions&lt;/em&gt; of years. In other words, when the diamond crystal formed, it grew around this type of mineral inclusion.&lt;/p&gt;&#xA;&lt;p&gt;As we can see, some diamonds may have a history that is very interesting. In particular regarding the present question, the small inclusions of davemaoite crystals would not exist at the earth's surface if not for the confining pressure formed consequent to the diamond's crystalline lattice of densely packed, covalently-bound carbon atoms. Recall that the crystalline structure of diamond is extraordinarily difficult to dislocate or shear, and the packing of carbon atoms in the crystal lattice is extraordinarily dense.  Consequently, each davemaoite inclusion was &lt;em&gt;trapped&lt;/em&gt; within the diamond crystal as the crystalline lattice grew around the inclusion. The unique crystalline covalent bonding structure of the diamond, itself, confines the davemaoite crystals at extreme pressure.&lt;/p&gt;&#xA;" OwnerUserId="24857" LastActivityDate="2021-11-14T04:30:05.160" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23154" PostTypeId="1" CreationDate="2021-11-14T08:28:07.577" Score="3" ViewCount="49" Body="&lt;p&gt;I know that every year carbon sinks remove ~20Gt of CO&lt;sub&gt;2&lt;/sub&gt; (about half of our emissions), and release a comparable amount of O&lt;sub&gt;2&lt;/sub&gt; , But I want to know how much O&lt;sub&gt;2&lt;/sub&gt;  the carbon sinks produce annually percentage wise (of the total atmosphere composition) considering the total annual carbon flux of ~800 Gt of CO&lt;sub&gt;2&lt;/sub&gt; .&lt;/p&gt;&#xA;" OwnerUserId="22045" LastEditorUserId="2470" LastEditDate="2021-11-14T11:28:08.233" LastActivityDate="2021-11-21T13:35:47.460" Title="What is the atmospheric percentage of oxygen produced by trees and phytoplankton every year?" Tags="|atmosphere|atmosphere-modelling|atmospheric-chemistry|greenhouse-gases|oxygen|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23155" PostTypeId="2" ParentId="23140" CreationDate="2021-11-14T17:50:11.550" Score="6" Body="&lt;p&gt;There's no formal link between the UNFCCC COP and IPCC Assessment Report timetables, but the reports do take the needs of UNFCCC activities into account when planning their timetable.&lt;/p&gt;&#xA;&lt;p&gt;The COP meetings &lt;a href=&quot;https://en.wikipedia.org/wiki/United_Nations_Climate_Change_conference&quot; rel=&quot;noreferrer&quot;&gt;happen every year&lt;/a&gt;, but most of them are much smaller than COP26 and are mostly concerned with ironing out technical details of existing agreements and laying the ground work for future agreements.  The COP3 in Kyoto in 1997 yielded the Kyoto Protocol and subsequent COP meetings have also served as CMPs (COP acting as a Meeting of the Parties to the Kyoto Protocol) that do things like agree changes to the reporting methods for national greenhouse gas emission inventories.  As the Protocol was coming to an end in 2020, COP21 in Paris in 2015 was targeted as the meeting where it's replacement would be negotiated and agreed, which was why that meeting was another large one.  That meeting yielded the Paris Agreement and subsequent COP meetings have also served as CMAs (COP acting as a Meeting of the Parties to the Paris Agreement).&lt;/p&gt;&#xA;&lt;p&gt;Under the Paris Agreement, Parties have to register their emission targets every five years and make them more ambitious than their last targets, which brings us to 2020, the original scheduled date for COP26 before Covid intervened.  So COP26 in Glasgow naturally became the venue where the Parties would commit to the next revision of their targets, making it another large meeting.&lt;/p&gt;&#xA;&lt;p&gt;None of that was dictated by the timetable for the IPCC AR6.  Similarly, &lt;a href=&quot;https://www.ipcc.ch/meeting-doc/ipcc-43-nairobi-kenya-11-13-april-2016&quot; rel=&quot;noreferrer&quot;&gt;minutes from early AR6 planning in 2016&lt;/a&gt; show that that report was never intended to be finalized before COP26.  From a planning paper (&lt;a href=&quot;https://www.ipcc.ch/apps/eventmanager/documents/37/140320160513-Doc.9_StrategicPlan.pdf&quot; rel=&quot;noreferrer&quot;&gt;pdf&lt;/a&gt;):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;a. ... which establishes that the AR6 cycle ending one year after the session at which the final product of the AR6 has been accepted, expected to end in 2022.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In other words, Working Group I, II and III reports would all be available by late 2021, a year after the original COP26 date.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;b. The second is that it is unlikely that Working Group I (WG I) would be able to submit to the Panel its contribution to the AR6 before November 2020...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;They didn't expect that even the WGI report would be available by COP26.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;c. In order to meet the needs of the United Nations Framework Convention on Climate Change (UNFCCC) the Panel would need to consider a Special Report (SR1) on  the impacts of global  warming  of  1.5°C  above  pre-industrial  levels  and  related  global  greenhouse  gas emission pathways in September 2018.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;That was okay because the AR6 cycle would include earlier reports that would inform the needs of the UNFCCC process.&lt;/p&gt;&#xA;&lt;p&gt;As some commenters above note, the Parties already had the information they needed to make emission commitments - from the IPCC Special Reports on &lt;a href=&quot;https://www.ipcc.ch/report/sr15/&quot; rel=&quot;noreferrer&quot;&gt;1.5°C&lt;/a&gt;, Land and Ocean, from their own commissioned reports and from the scientific literature that's already published (and which the IPCC reports merely summarize).&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2021-11-14T17:50:11.550" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23156" PostTypeId="2" ParentId="22874" CreationDate="2021-11-14T20:06:42.657" Score="-1" Body="&lt;p&gt;I have several hypotheses.&lt;/p&gt;&#xA;&lt;p&gt;Nature is involved in the formation of rain. &lt;a href=&quot;https://www.youtube.com/watch?v=gu9UmHbmFfk&quot; rel=&quot;nofollow noreferrer&quot;&gt;How Mushrooms Make It Rain - YouTube&lt;/a&gt;. &lt;a href=&quot;https://www.youtube.com/watch?v=DvuQzRNe8ks&quot; rel=&quot;nofollow noreferrer&quot;&gt;How Trees Control the Weather&lt;/a&gt;. Nature may purposely release particles to form clouds. Water molecules in the atmosphere cannot form a rain droplet without a bigger particle of other type. Human activity may damage the natural system.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;There are particles produced by humans in the atmosphere like smoke, dust, microplastics. They may cause water molecules to form rain too early.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Water in the atmosphere is a greenhouse gas. The global mean (average) temperature is rising because of greenhouse gases released by humans. Nature (global ecosystem) may purposely remove water from the atmosphere (by releasing particles) in order to reduce temperature.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Plants grown by humans may not have the correct program in them to release particles on time to support good rain schedule. Plants grown naturally keep local DNA, humans often grow plants from seeds taken from comparatively far away. Also, naturally grown plants may educate each others via signals.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="18752" LastEditorUserId="18752" LastEditDate="2023-01-27T13:30:55.857" LastActivityDate="2023-01-27T13:30:55.857" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23157" PostTypeId="2" ParentId="22874" CreationDate="2021-11-15T06:56:38.190" Score="1" Body="&lt;p&gt;Warmer air holds more moisture. That means when and where conditions for rainfall reliably occur the likelihood of higher than historic average levels of rainfall is increased because of global warming.&lt;/p&gt;&#xA;&lt;p&gt;It also means that where such conditions are uncommon rainfall is reduced, because warmer air requires more water vapor to reach saturation and that condition is harder to reach.&lt;/p&gt;&#xA;&lt;p&gt;The regions mentioned with the question, that are affected by reduced rainfall tend to historically have periods of low rainfall, often related to ocean circulation based phenomena like El Nino Southern Oscillation, Indian Dipole, Atlantic Nino and others that change the distribution of warm and cool surface water, which in turn impacts wind patterns and the amount of water vapor they take up. In combination with warming they can enhance or inhibit evaporation and consequently rainfall.&lt;/p&gt;&#xA;&lt;p&gt;It does seem likely that global warming is changing those wind patterns as well as their intensity, with consequences for rainfall, in addition to the impacts of the raised capacity to hold water vapor and the raised water vapor threshold for precipitation.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2021-11-15T06:56:38.190" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23161" PostTypeId="1" CreationDate="2021-11-16T17:59:29.937" Score="1" ViewCount="53" Body="&lt;p&gt;I am in &lt;strong&gt;no way&lt;/strong&gt; a climate-change skeptic, nor a denier. Motivated by &lt;a href=&quot;https://earthscience.stackexchange.com/questions/23144/how-to-explain-the-remarkable-regularity-of-the-increased-concentration-of-atmos?newreg=f650c03c5b034a238aed9a2797b036b5&quot;&gt;this&lt;/a&gt; question and some articles I read online:&lt;/p&gt;&#xA;&lt;p&gt;Are there any known natural processes beside human activities that are able to explain the (geologically recent) rise in atmospheric CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; concentration?&lt;/p&gt;&#xA;&lt;p&gt;I'm also curious about this because I often hear climate change skeptics bring this up and I'm not sure how to respond.&lt;/p&gt;&#xA;" OwnerUserId="24873" LastEditorUserId="24873" LastEditDate="2021-11-16T20:42:59.463" LastActivityDate="2021-11-16T20:42:59.463" Title="Alternative natural explanations for rise in atmospheric CO2?" Tags="|climate-change|co2|carbon-cycle|human-influence|" AnswerCount="0" CommentCount="7" ClosedDate="2021-11-16T22:18:11.390" ContentLicense="CC BY-SA 4.0" />
  <row Id="23162" PostTypeId="2" ParentId="23144" CreationDate="2021-11-16T19:07:13.357" Score="1" Body="&lt;p&gt;The trend has actually not been stable. Per the &lt;a href=&quot;https://scrippsco2.ucsd.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scripps CO2 Group&lt;/a&gt;, which along with NOAA monitors CO2 levels at Mauna Loa:&lt;/p&gt;&#xA;&lt;p&gt;[&amp;gt; The rate of growth in carbon dioxide concentrations in the atmosphere&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;has accelerated since the beginnings of the Keeling Curve.  The rate&#xA;has gone from about 0.75 parts per million (ppm)/yr in 1959 to about&#xA;2.25ppm/yr today.]&lt;a href=&quot;https://keelingcurve.ucsd.edu/2015/02/12/is-the-rate-of-co2-growth-slowing-or-speeding-up/&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&amp;quot;Today&amp;quot; being in 2015, when this item was originally posted to the Keeling Curve website.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2021-11-16T19:07:13.357" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23163" PostTypeId="2" ParentId="23148" CreationDate="2021-11-16T21:36:56.583" Score="8" Body="&lt;p&gt;Yes, this is a rather nice find; an ammonite of the Jurassic in central Europe. Given the size of the specimen, and its appearance, this appears to be of the species &lt;em&gt;Cardioceras&lt;/em&gt;, or &lt;em&gt;Perisphinctes.&lt;/em&gt;  These ammonoids belong to the Class Cephalopoda, the coiled cephalopods.  They lived about 160 million years ago.  The Order of ammonites to which &lt;em&gt;Cardioceras&lt;/em&gt; and &lt;em&gt;Perisphinctes&lt;/em&gt; belong is called the ammonitids, which began their evolutionary path in the Jurassic, flourishing in the Triassic and Cretaceous, then becoming extinct at the end of the Cretaceous.  A common species of a different Subclass, the nautiloids, is related to these Jurassic ammonites.  This is &lt;em&gt;Nautilus&lt;/em&gt;, among the most primitive of the cephalopods, and still living today.&lt;/p&gt;&#xA;&lt;p&gt;The central part of the fossil appears to be well silicified and filled with quartz. The faint outer region is also a part of this fossil as the outer edge has a preserved part of the shell which is visible. The central part of the fossil shows several distinct &lt;em&gt;camerae.&lt;/em&gt;  Each camera is formed as the abandoned living chamber that is walled off as the animal grew and formed a new living chamber.  The last living chamber of this animal is likely the faint outer region surrounding the central quartz filled area.  With some estimation, one may count approximately 16 or 17 previous living chambers, with the last (or 18th) being open.&lt;/p&gt;&#xA;&lt;p&gt;The host rock shows one other fragmentary view of an ammonite, readily seen by the distinct ridges of the corrugations in the shell.  There are other fossil fragments also visible.  They were not readily identified, however.&lt;/p&gt;&#xA;" OwnerUserId="24875" LastActivityDate="2021-11-16T21:36:56.583" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23164" PostTypeId="1" CreationDate="2021-11-17T02:41:26.357" Score="8" ViewCount="1627" Body="&lt;p&gt;Many references state that pumice is formed by gases in lava, but I have yet to find a reference of which gases they are. If a piece of pumice floats, then conceivably it still contains the original gases from the magma, right?&lt;/p&gt;&#xA;&lt;p&gt;Breaking the pumice would release the gas trapped in the vesicles.&lt;/p&gt;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://www.tulane.edu/%7Esanelson/Natural_Disasters/volcan&amp;amp;magma.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.tulane.edu/~sanelson/Natural_Disasters/volcan&amp;amp;magma.htm&lt;/a&gt;, the gases in magma are&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Mostly H&lt;sub&gt;2&lt;/sub&gt;O (water vapor) &amp;amp; some CO&lt;sub&gt;2&lt;/sub&gt; (carbon dioxide)&lt;/li&gt;&#xA;&lt;li&gt;Minor amounts of Sulfur, Chlorine, and Fluorine gases&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;But is this true for pumice? If it's mostly water vapor in the gas, then when it cools, the pumice holes would contain liquid water, albeit small amounts compared to the size of the vesicles.&lt;/p&gt;&#xA;&lt;p&gt;Otherwise, does pumice typically have other gases?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit&lt;/strong&gt;: Here's some background for this question. My 7yo son asked me where the bubbles in pumice came from, when I showed him that this &amp;quot;rock&amp;quot; can float. Google didn't give a good answer, so after he went to bed I started searching... Kids ask the best questions!&lt;/p&gt;&#xA;" OwnerUserId="24877" LastEditorUserId="24877" LastEditDate="2021-11-17T16:10:39.763" LastActivityDate="2021-11-27T10:50:35.923" Title="What gases are in the vesicles of pumice?" Tags="|geology|volcanology|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23166" PostTypeId="2" ParentId="23164" CreationDate="2021-11-17T08:39:34.067" Score="13" Body="&lt;p&gt;Pumice does not contain any gas, the vesicles are empty&lt;sup&gt;1&lt;/sup&gt;. The magma which generated the pumice &lt;em&gt;used to&lt;/em&gt; contain gas, mostly water and CO&lt;sub&gt;2&lt;/sub&gt; like you said. But this gas was lost during the eruption. Most of the vesicles are actually connected, allowing the gas to escape. The connectivity &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; is defined as:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$C = \frac{\phi'}{\phi}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$\phi'$&lt;/span&gt; is the connected porosity, and &lt;span class=&quot;math-container&quot;&gt;$\phi$&lt;/span&gt; is the bulk porosity. So &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; varies from 0 (no connectivity, all vesicles are isolated) to 1 (all vesicles are connected).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1016/j.epsl.2017.01.011&quot; rel=&quot;noreferrer&quot;&gt;Colombier et al. (2017)&lt;/a&gt; compiled a database of connectivity measurements of volcanic rocks, the results are summarized by this figure:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5Y6gu.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5Y6gu.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The covariance of &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; with &lt;span class=&quot;math-container&quot;&gt;$ϕ$&lt;/span&gt; for all natural rocks classified by bulk rock composition&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You can see that connectivity in pumice (panels a, c, d, and e) is very high, usually between 0.8 and 1.0, meaning that most of the porosity is connected, allowing gas to escape through the pore network. As for the causes of such high connectivity, the study states:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Pore connectivity develops by vesiculation and bubble growth-driven coalescence or by cracking or combinations of both processes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt;Well, as pointed out in a comment, connected vesicles are actually filled with atmospheric gases.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2021-11-17T14:30:14.623" LastActivityDate="2021-11-17T14:30:14.623" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="23167" PostTypeId="1" AcceptedAnswerId="23175" CreationDate="2021-11-17T12:06:41.763" Score="1" ViewCount="43" Body="&lt;p&gt;I want to see how well different CMIP6 model realisations did during the model evaluation, but I can't find papers associated with the data presented on the ESGF node. For example, if I was interested in the EC-Earth3 model and specific variant, where can I find out how it performed?&lt;/p&gt;&#xA;&lt;p&gt;I haven't found an article specifically referring to EC-Earth3, but rather one referring to the AerChemMIP realisation, as opposed to the ScenarioMIP realisation I am interested in. Is it possible that the data from these models contribute to CMIP6 without any peer-reviewed evaluation of the outputs?&lt;/p&gt;&#xA;" OwnerUserId="24395" LastActivityDate="2021-11-19T13:58:55.257" Title="Where can I find the journal articles associated with CMIP6 models available on World Climate Reseaerch Programme ESGF website?" Tags="|climate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23168" PostTypeId="2" ParentId="23164" CreationDate="2021-11-17T14:39:49.853" Score="5" Body="&lt;p&gt;The work of Formenti et al. in &lt;a href=&quot;https://www.eri.u-tokyo.ac.jp/people/ichihara/vp2007plan/Formenti%20and%20Druitt%202003%20EPSL.pdf&quot; rel=&quot;noreferrer&quot;&gt;&lt;em&gt;Earth and Planetary Science Letters&lt;/em&gt; 214 (2003) 561&lt;/a&gt; disagrees with the idea that pumice can never retain original gases (emphasis added):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Our observations show that dense blocks derived from lava domes are commonly not able to retain gas because essentially all the vesicles are interconnected, as also found by Le Pennec et al. [18] in an electrical conductivity study of samples of Merapi lava dome. On the other hand, typically a few volume percent of vesicles in pumices from fountain-collapse pyroclastic flows at Soufrière Hills and Lascar are isolated, showing that &lt;strong&gt;gas can be retained in isolated vesicles of pumices even after cooling and deposition&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Unfortunately, they don't have any information on what the contents of the vesicles would be. It was &lt;a href=&quot;http://earth.geology.yale.edu/%7Eajs/1938-A/311.pdf&quot; rel=&quot;noreferrer&quot;&gt;discovered in the 1920s&lt;/a&gt; that pumice did not retain sufficient original gases to be useful as a sample of volcanic gas. Scientists decided it was easier to catch the gases emerging from the volcano than to try to sample the highly contaminated contents of crushed pumice. Even with modern techniques, the difficulty of determining the contents of isolated vesicles is simply too high, since they presumably contain the same gases as emitted from volcanic vents.&lt;/p&gt;&#xA;" OwnerUserId="2951" LastActivityDate="2021-11-17T14:39:49.853" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23169" PostTypeId="1" CreationDate="2021-11-17T23:06:56.253" Score="1" ViewCount="67" Body="&lt;p&gt;There are clear ways climate change can and does harm Russia: more frequent forest fires, floods, thawing permafrost. On the other hand, winter, says the latest IPCC report, is going to warm at a higher rate than summer, potentially making living in the country more, not less bearable.&lt;/p&gt;&#xA;&lt;p&gt;Besides, there is at least one obvious economic advantage called the &lt;a href=&quot;https://en.wikipedia.org/wiki/Northern_Sea_Route&quot; rel=&quot;nofollow noreferrer&quot;&gt;Northern Sea Route&lt;/a&gt; (if not for the Russian people, then at least for Putin's mafioso buddy Ilya Traber wanted by the Spanish police for a range of crimes and who &lt;a href=&quot;https://web.archive.org/web/20210119194340/https://www.proekt.media/film/traber-porty/&quot; rel=&quot;nofollow noreferrer&quot;&gt;co-owns&lt;/a&gt; the ports along the route).&lt;/p&gt;&#xA;&lt;p&gt;Furthermore, a relatively recent study &lt;a href=&quot;https://www.nature.com/articles/s41558-018-0282-y&quot; rel=&quot;nofollow noreferrer&quot;&gt;published in Nature&lt;/a&gt; corroborates the suggestion that the benefits of climate change are going to outweigh the disadvantages for Russia.&lt;/p&gt;&#xA;&lt;p&gt;Is Russia going to benefit from climate change? If so, is there any particular reason the Russian government should lift a finger about it (it's clear they don't care about the Maldives going underwater)?&lt;/p&gt;&#xA;&lt;p&gt;I'm asking this in part because Putin's rhetoric in the recent year or so kind of changed: if at first, he was more &lt;a href=&quot;https://meduza.io/feature/2019/07/11/putin-skazal-chto-vetryanye-elektrostantsii-izgonyayut-chervey-iz-zemli-i-ubivayut-ptits-eto-pravda&quot; rel=&quot;nofollow noreferrer&quot;&gt;worried&lt;/a&gt; about worms being driven out of soil by wind turbines, later on he suddenly &lt;a href=&quot;https://www.rbc.ru/society/31/10/2021/617e7edf9a79470a51305ed5&quot; rel=&quot;nofollow noreferrer&quot;&gt;started&lt;/a&gt; to underscore the dangers that climate change poses for Russia.&lt;/p&gt;&#xA;" OwnerUserId="22632" LastEditorDisplayName="user20559" LastEditDate="2021-11-18T13:17:31.030" LastActivityDate="2021-11-18T13:17:31.030" Title="Is Russia going to benefit from climate change?" Tags="|climate-change|" AnswerCount="0" CommentCount="3" ClosedDate="2021-11-19T13:10:53.063" ContentLicense="CC BY-SA 4.0" />
  <row Id="23170" PostTypeId="2" ParentId="10493" CreationDate="2021-11-18T03:28:40.893" Score="6" Body="&lt;p&gt;According to this Wikipedia entry &lt;a href=&quot;https://en.wikipedia.org/wiki/Sprite_(lightning)&quot; rel=&quot;noreferrer&quot;&gt;Sprites&lt;/a&gt; occur at altitudes between 50 and 90km while the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cumulonimbus_cloud&quot; rel=&quot;noreferrer&quot;&gt;thunderstorms that create them&lt;/a&gt; generally top out below 16km so there is a minimum of more than 30km of height difference between a storm and any sprites it may spawn. So yes, at the right angle, you should be able to get a photograph of a storm's sprites from the ground. Whether the storm we can see in the photo is in fact the source of those sprites I don't know, given the angles I think the part of the storm that created them is actually below the horizon.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2021-11-18T03:28:40.893" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="23171" PostTypeId="1" CreationDate="2021-11-18T11:20:48.990" Score="1" ViewCount="46" Body="&lt;p&gt;A lot of the press discussion, IPCC information and scientific inquiry about climate change refers to changes in the &lt;strong&gt;temperature&lt;/strong&gt; of the atmosphere. I have not seen debates about changes in the &lt;strong&gt;composition&lt;/strong&gt; of the atmosphere. In particular, could human activity make air unbreathable? This would be of course disastrous for human life (and for other species). Or perhaps this process would be so slow that our respiratory system would adapt to it?&lt;/p&gt;&#xA;&lt;p&gt;There are some isolated scientists suggesting we could make air unbreathable (like &lt;a href=&quot;https://inhabitat.com/runaway-carbon-emissions-threaten-two-thirds-of-the-earths-oxygen-supply/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;), but the lack of wider treatment of this issue suggests to me this is not really a problem. What is the scientific standing about this possibility?&lt;/p&gt;&#xA;&lt;p&gt;Update: the suggested duplicate focuses &lt;strong&gt;solely&lt;/strong&gt; on CO2. My question is broader. Air composition could change because of different factors, like the Oxigen-plankton relationship highlighted in the referred link. The other post is too narrow. This is broader.&lt;/p&gt;&#xA;" OwnerUserId="13541" LastEditorUserId="13541" LastEditDate="2021-11-19T08:48:53.957" LastActivityDate="2021-11-19T08:48:53.957" Title="Could climate change make air unbreathable?" Tags="|climate-change|atmosphere|human-influence|air|" AnswerCount="0" CommentCount="2" ClosedDate="2021-11-20T06:27:03.800" ContentLicense="CC BY-SA 4.0" />
  <row Id="23174" PostTypeId="1" AcceptedAnswerId="23179" CreationDate="2021-11-19T03:29:10.957" Score="2" ViewCount="2521" Body="&lt;p&gt;I'm trying to reconcile a paradox regarding air pressure and temperature.&lt;/p&gt;&#xA;&lt;p&gt;On the one hand, compressing air heats it up, while expanding it cools it. So density and temperature are proportional.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, warm air in the atmosphere is a low pressure system and cold air is a high pressure system. So density and temperature are inversely proportional.&lt;/p&gt;&#xA;&lt;p&gt;What am I missing in order to reconcile the two?&lt;/p&gt;&#xA;" OwnerUserId="24893" LastEditorUserId="543" LastEditDate="2021-11-20T18:50:58.443" LastActivityDate="2021-11-22T21:36:41.650" Title="What is the relationship between air pressure and temperature?" Tags="|meteorology|temperature|fluid-dynamics|pressure|air|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="23175" PostTypeId="2" ParentId="23167" CreationDate="2021-11-19T13:58:55.257" Score="2" Body="&lt;p&gt;Unfortunately, while there's lots of coordination of the CMIP6 experiment protocols across the modelling groups, there's little coordination of the evaluation of outputs, which is done in different ways by different groups.  There's a&#xA;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/topic/vi-categories-19422466/earth-system-modeling-2018-2020/19422466&quot; rel=&quot;nofollow noreferrer&quot;&gt;JAMES Special Collection&lt;/a&gt; of Special Issues covering some models (CAS-ESM, CESM2, IPSL, GISS, CNRM, E3SM, GFDL, HadGEM3, MPI-ESM1.2) and several GMD Special Issues for individual models (e.g., &lt;a href=&quot;https://gmd.copernicus.org/articles/special_issue989.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;CanESM&lt;/a&gt;, &lt;a href=&quot;https://gmd.copernicus.org/articles/special_issue20.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NorESM&lt;/a&gt;, &lt;a href=&quot;https://gmd.copernicus.org/articles/special_issue1027.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ACCESS&lt;/a&gt;).  These are used differently by each group; some use them just to document the model, some also use them for model evaluation and science results.&lt;/p&gt;&#xA;&lt;p&gt;EC-Earth seems to be notable for an absence of a special issue.  There's a paper on &lt;a href=&quot;https://gmd.copernicus.org/preprints/gmd-2020-446/&quot; rel=&quot;nofollow noreferrer&quot;&gt;EC-Earth3 historical simulations&lt;/a&gt; and an &lt;a href=&quot;https://eartharxiv.org/repository/view/267/&quot; rel=&quot;nofollow noreferrer&quot;&gt;EC-Earth3 report&lt;/a&gt; but nothing obviously coordinated.  The information is probably scattered across various papers and journals.&lt;/p&gt;&#xA;&lt;p&gt;It's worth noting that CMIP6 outputs are pushed through various standard benchmarking tools and put on the web, which you might find useful: e.g., &lt;a href=&quot;https://www.ilamb.org/CMIP6/historical&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ilamb.org/CMIP6/historical&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Is it possible that the data from these models contribute to CMIP6 without any peer-reviewed evaluation of the outputs?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Yes and no.  Pretty much every group will have some form of internal evaluation and sanity check of their model outputs before publishing them to the ESGF.  Some groups require a human to approve every single file that gets published.  But with each CMIP6 model producing petabytes of data, this internal post-processing, review and publication work flow requires a significant amount of effort by each group (e.g., &lt;a href=&quot;https://opensky.ucar.edu/islandora/object/conference%3A2967/datastream/PDF/view&quot; rel=&quot;nofollow noreferrer&quot;&gt;CESM at NCAR&lt;/a&gt;).  It's just not practical for all that data to also be formally peer-reviewed just for the purpose of sitting in a database.&lt;/p&gt;&#xA;&lt;p&gt;In practice though, each science paper that uses those data is a form of peer-review (because none of us should use any data without sanity checking it for ourselves), and those papers will themselves have traditional, formal peer-review before being published.  (I've had to contact other modelling groups about oddities in their data I've found while writing a paper and sometimes they have the resources to fix the dataset, sometimes they don't.)  So you could say that these datasets have at least three levels of review, and probably more.  One of the benefits of making these data on the ESGF available to anyone is that they are scrutinized by far more people, friendly and unfriendly, than happens under traditional peer-review.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2021-11-19T13:58:55.257" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23177" PostTypeId="2" ParentId="23174" CreationDate="2021-11-19T18:57:42.697" Score="1" Body="&lt;p&gt;Compression and expansion of an ideal gas is an adiabatic process, i.e. the entropy &lt;span class=&quot;math-container&quot;&gt;$\rm (P\rho^{-\gamma}) = const$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$\gamma$&lt;/span&gt; is the adiabatic constant.&lt;br /&gt;&#xA;You can rearrange this using the ideal gas closure relation &lt;span class=&quot;math-container&quot;&gt;$\rm P=\rho kT/\mu$&lt;/span&gt; to find &lt;span class=&quot;math-container&quot;&gt;$\rm (T\rho^{1-\gamma}) = const.$&lt;/span&gt;, which is essentially the statement you gave prior, that compressed gases are hotter (becasue &lt;span class=&quot;math-container&quot;&gt;$\gamma&amp;gt;1 $&lt;/span&gt; for realistic gases) if their entropy remains constant.&lt;/p&gt;&#xA;&lt;p&gt;The air in the atmosphere however does not have constant entropy, and thus its &lt;span class=&quot;math-container&quot;&gt;$T(\rho)$&lt;/span&gt;-behaviour is different from the adiabatic one. Instead, it follows a force-balance, i.e. the hydrostatic law &lt;span class=&quot;math-container&quot;&gt;$\partial P/\partial r = -g(r) \rho(r)$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$g(r) = -GM/r^2$&lt;/span&gt;. The resulting density structure from this is &lt;span class=&quot;math-container&quot;&gt;$\rho(r) = \rho_0 \times \exp(-H(\frac{1}{r}-\frac{1}{r_0}))$&lt;/span&gt; with the atmospheric density scale height &lt;span class=&quot;math-container&quot;&gt;$H=kT/GM \mu$&lt;/span&gt; and 0-index quantities denote density and radius on the surface.&lt;br /&gt;&#xA;Now we just have to relate &lt;span class=&quot;math-container&quot;&gt;$\rho_0$&lt;/span&gt; to other, known quantities, which we can do when assuming that the entirety of the atmospheric mass &lt;span class=&quot;math-container&quot;&gt;$\rm M_{atmo}$&lt;/span&gt; is contained in one scale height of the atmosphere, then we get &lt;span class=&quot;math-container&quot;&gt;$\rm M_{atmo} = 4\pi \rho_0 H R_0^2$&lt;/span&gt;.&lt;br /&gt;&#xA;One immediately sees that &lt;span class=&quot;math-container&quot;&gt;$\rm \rho_0 \sim 1/H \sim 1/T$&lt;/span&gt;. This shows that for a colder atmosphere (smaller H), the density on the ground must be larger, when following the force balance instead of entropy conservation.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Short, less-mathy summary:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Compressed gas naturally heats up. If no exchange of heat with the environment occurs, then after some time we can expand the gas, to cool it back to its exact same initial temperature.&lt;br /&gt;&#xA;This is called an adiabatic process, kind of a central vocabulary from thermodynamics.&lt;/p&gt;&#xA;&lt;p&gt;Now if we allow for a process to be diabatic, i.e. we allow for the gas to exchange energy with the environment, then it's temperature cannot be set by the adiabatic condition. Instead, we must look to what else is acting on the gas.&lt;br /&gt;&#xA;A planet's atmosphere is kept by its gravity, and it is the gravitational energy which sets a different behaviour: In a gravitational field, a cold gas volume must be a compressed compressed one, because it does not have enough pressure to resist gravity. Hot gas can expand far up the gravity well of a planet.&lt;/p&gt;&#xA;&lt;p&gt;This is a bit simplified, as one can of course also have an adiabatic gas in a gravitational field, but I would only go there in this answer, if there is interest.&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="489" LastEditDate="2021-11-22T21:36:41.650" LastActivityDate="2021-11-22T21:36:41.650" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23178" PostTypeId="1" CreationDate="2021-11-19T19:45:07.743" Score="1" ViewCount="55" Body="&lt;p&gt;Consider a square &lt;strong&gt;2D domain&lt;/strong&gt; and a &lt;strong&gt;steady-state simulation&lt;/strong&gt;. &lt;strong&gt;According to the geology of the domain&lt;/strong&gt;, the North, South, West and East &lt;strong&gt;limits must be conditions of zero flow (Neumann)&lt;/strong&gt;. The aquifer receives a uniform recharge R throughout the area. In the center of the aquifer, there is a well which pumps at the rate Q. The aquifer is considered to be homogeneous and isotropic. The equation in the (unconfined) aquifer is therefore:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;K * hxx + K * hyy = R + Q&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;With hxx : second derivative of the hydraulic head following x direction &amp;amp; K: hydraulic conductivity.&lt;/p&gt;&#xA;&lt;p&gt;I tried to build a numerical simulation model with the above boundary conditions but it does not converge. &lt;strong&gt;Is this normal?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Geology forces me to impose a zero flux limit on all boundaries of the real domain. &lt;strong&gt;Should I depart from these real limits&lt;/strong&gt; and impose arbitrary conditions that make the model converge?&lt;/p&gt;&#xA;" OwnerUserId="24724" LastActivityDate="2021-11-22T22:46:15.183" Title="Can we know if a numerical model will converge or not according to the boundary conditions?" Tags="|hydrology|models|numerical-modelling|hydrogeology|mathematics|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23179" PostTypeId="2" ParentId="23174" CreationDate="2021-11-20T07:16:21.323" Score="2" Body="&lt;p&gt;Or if the math of the other answers is a bit complex, in a broad sense, the balancing relationship is: &lt;span class=&quot;math-container&quot;&gt;$$\frac{\mathrm{density} \cdot \mathrm{temperature}}{\mathrm{pressure}} = \mathrm{constant}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;For compression, that's pretty straightforward: higher pressure forces higher density and temperature.&lt;/p&gt;&#xA;&lt;p&gt;In the atmosphere, that balance still endures.  But there can be &lt;a href=&quot;https://en.wikipedia.org/wiki/High-pressure_area#:%7E:text=The%20subtropical%20ridge%20is%20a,these%20climatological%20high-pressure%20systems.&amp;amp;text=Arctic%20high-pressure%20systems%20such,that%20they%20weaken%20with%20height.&quot; rel=&quot;nofollow noreferrer&quot;&gt;warm highs&lt;/a&gt;, &lt;a href=&quot;https://www.theweatherprediction.com/habyhints2/613/&quot; rel=&quot;nofollow noreferrer&quot;&gt;warm lows&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Polar_High&quot; rel=&quot;nofollow noreferrer&quot;&gt;cold highs&lt;/a&gt;, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Cold-core_low&quot; rel=&quot;nofollow noreferrer&quot;&gt;cold lows&lt;/a&gt;, depending upon density distribution.&lt;/p&gt;&#xA;&lt;p&gt;The formation of such areas of pressure extreme is intimately connected to the three-dimensional structure of the atmosphere ... atmospheric pressure is [basically] the weight of air above ... vertical motion is heavily driven by buoyancy [air's density compared to air around it] ... and forces at a distance induce air motion [wind is related to the gradient of pressure and other forces].&lt;/p&gt;&#xA;&lt;p&gt;All of which is to say there are a lot of interactions which allow for a rich variety of pressure-temperature-density balances, the 3-dimensional structures of those systems, and the resulting wind, precipitation, etc.  There's a whole focus of thermodynamics that looks &lt;a href=&quot;https://opentextbc.ca/universityphysicsv2openstax/chapter/thermodynamic-processes/#:%7E:text=An%20adiabatic%20process%2C%20during%20which,system%27s%20volume%20does%20not%20change&quot; rel=&quot;nofollow noreferrer&quot;&gt;at the variety of controls in processes&lt;/a&gt; which can lead to different results.&lt;/p&gt;&#xA;&lt;p&gt;But in the end, that balance between ρ, P, and T in gases is what matters, and the factor you overlooked is that &lt;strong&gt;density and pressure are not the same thing&lt;/strong&gt;.  It may seem like how much pressure is exerted by\upon a gas is the same as how compressed the mass of air actually is... but it's not... how fast the molecules in the gas move (which is its temperature) is the third factor, and there are ways that any two can change, or all three change at the same time, but the overall balance remains.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2021-11-20T07:16:21.323" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23180" PostTypeId="2" ParentId="15865" CreationDate="2021-11-20T11:46:43.390" Score="6" Body="&lt;p&gt;Note that in addition to Camilo's answer, &lt;a href=&quot;https://en.wikipedia.org/wiki/Highest_temperature_recorded_on_Earth#:%7E:text=Satellite%20measurements%20of%20ground%20temperature,in%20the%20Lut%20Desert%2C%20Iran.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia links&lt;/a&gt; to &lt;a href=&quot;https://journals.ametsoc.org/view/journals/bams/92/7/2011bams3067_1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;a peer reviewed BAMS article&lt;/a&gt; noting that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Satellite measurements of ground temperature taken between 2003 and&#xA;2009, taken with the MODIS infrared spectroradiometer on the Aqua&#xA;satellite, found a maximum temperature of &lt;strong&gt;70.7 °C (159.3 °F)&lt;/strong&gt;, which&#xA;was recorded &lt;strong&gt;in 2005 in the Lut Desert, Iran&lt;/strong&gt;. The Lut Desert was also&#xA;found to have the highest maximum temperature in 5 of the 7 years&#xA;measured (2004, 2005, 2006, 2007, and 2009). These measurements&#xA;reflect averages over a large region and so are lower than the maximum&#xA;point surface temperature&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Indeed we only have observation stations at very limited desert locations, as we tend to put them where power and human resources (for repairs and such) are available.  So the most remote locations like in the heart of the Sahara don't have a lot of measurements.  &lt;a href=&quot;https://www.cpc.ncep.noaa.gov/products/international/gts1/gts_africa_tmax_1d.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;See this map of today's observations&lt;/a&gt; for example (&lt;a href=&quot;https://i.stack.imgur.com/5QjlB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;here's an archived image from 11/20/21&lt;/a&gt; in case the link rots)  So satellite data, while perhaps not absolutely positively perfectly equatable, gives a better idea of what and where the true maximum temperatures on Earth are.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2021-11-22T08:00:13.183" LastActivityDate="2021-11-22T08:00:13.183" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23181" PostTypeId="2" ParentId="23122" CreationDate="2021-11-20T18:31:36.377" Score="1" Body="&lt;p&gt;From &lt;a href=&quot;https://www.thenakedscientists.com/forum/index.php?topic=83535.msg660453#msg660453&quot; rel=&quot;nofollow noreferrer&quot;&gt;the answer I received in The Nacked Scientists&lt;/a&gt; I must classify them as supergenic.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Freedictionary defines supergene processes as &amp;quot;processes of the physical and chemical conversion of mineral matter in the upper parts of the earth’s crust and on its surface through the action of the atmosphere, hydrosphere, and living organisms at low temperatures. They consist in chemical decomposition, solution, hydrolysis, hydration, oxidation, and carbonization&amp;quot;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So my classification will be:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Magmatic.&lt;/li&gt;&#xA;&lt;li&gt;Metamorphic.&lt;/li&gt;&#xA;&lt;li&gt;Hydrothermal.&lt;/li&gt;&#xA;&lt;li&gt;Sedimentary.&lt;/li&gt;&#xA;&lt;li&gt;Supergenic.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerDisplayName="user20559" LastActivityDate="2021-11-20T18:31:36.377" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23182" PostTypeId="1" AcceptedAnswerId="23229" CreationDate="2021-11-21T10:09:50.507" Score="4" ViewCount="103" Body="&lt;p&gt;I read that canyons are the result of long-time erosion from a plateau but is there any simulation I could play with to understand the phenomenon better?&lt;/p&gt;&#xA;" OwnerUserId="24905" LastEditorUserId="28050" LastEditDate="2021-11-30T17:49:37.763" LastActivityDate="2021-11-30T17:49:37.763" Title="How do canyons form?" Tags="|erosion|simulation|landscape|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23183" PostTypeId="1" AcceptedAnswerId="23184" CreationDate="2021-11-22T09:54:28.760" Score="1" ViewCount="86" Body="&lt;p&gt;Is there ever a state of thermal equilibrium between land and sea? What is the condition of the Land/Sea breeze at that time?&lt;/p&gt;&#xA;" OwnerUserId="24909" LastActivityDate="2021-11-23T06:29:39.090" Title="Does sea breeze stop?" Tags="|wind|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23184" PostTypeId="2" ParentId="23183" CreationDate="2021-11-22T12:13:11.087" Score="1" Body="&lt;p&gt;Thermal equilibrium suggests equal temperatures... in our active seabreeze season in Florida [early June - late September], that would mean temperatures generally in the low 80s °F (upper 20s °C)... which would be most common after sunset \ midmorning.&lt;/p&gt;&#xA;&lt;p&gt;Ocean currents can mean some areas have much cooler (or even warmer) water than the land airmass during long periods of the year.  So there are many places that have long stretches of the year when the seabreeze tends to stay quite strong (for example, the Pacific coast of California in the spring and summer) (it may be obvious for people in most areas, but I have remind myself that a seabreeze doesn't equate to thunderstorms in most places most of the time!)&lt;/p&gt;&#xA;&lt;p&gt;Would expect that the conditions at such a time would reflect the synoptic conditions at the time (the larger-scale regional conditions caused by the usual interplay between transient high and low pressures, airmass movement, vertical instability and mixing, etc).&lt;/p&gt;&#xA;&lt;p&gt;Note:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;This doesn't mean the wind will definitely go calm when the sea and land are at equal temperatures... there's typically some regional pressure gradient [minimal gradients tend to be limited to broad high pressures areas and near cols]... and other factors, too; for my Florida situation, by midmorning winds often start to increase because heating is causing vertical mixing which brings stronger winds speeds down towards the surface from aloft.  All that, plus the reduced friction over water, mean seashores\large lakeshores tend to be some of the rarer land locations to see calm winds, as &lt;a href=&quot;https://i.stack.imgur.com/JASiA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;this hourly August wind climatology of a coastal Florida site shows&lt;/a&gt; (they only see calm winds &lt;a href=&quot;https://i.stack.imgur.com/FJKlm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;4.5% of the time&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Likewise the wind can go calm at the seashore at times even when a large thermal imbalance exists... if the synoptic conditions oppose the local thermally-induced sea-land pressure gradient.  A rough idea of the conditions that do this would be:&lt;br /&gt;&#xA;In the Northern Hemisphere, the synoptic winds should oppose the seabreeze if synoptic low pressure is off to the left \ synoptic high pressure is off to the right when looking at the ocean along a regionally representative shoreline during the daytime...&lt;br /&gt;&#xA;And the synoptic winds will oppose the landbreeze if synoptic low pressure is off to the right \ synoptic high pressure is off to the left when looking at the ocean along a representative shoreline during the night\early morning.&lt;br /&gt;&#xA;(Flip directions for SH)&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Also it's worth noting that seabreeze boundary &amp;quot;fronts&amp;quot; can penetrate quite far inland and take time to fade away... even after temperatures have equalized at the shoreline or the landbreeze has started to develop near the coast... and if there are thunderstorms along the seabreeze boundaries, the &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9306/is-it-typically-colder-after-a-storm/9307&quot;&gt;cool air released by the rainfall&lt;/a&gt; often further reinforces the thermal gradient...  I've certainly seen seabreeze boundaries persist deep into the night hundreds of miles from the coast.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2021-11-23T06:29:39.090" LastActivityDate="2021-11-23T06:29:39.090" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23185" PostTypeId="1" CreationDate="2021-11-22T19:21:30.960" Score="1" ViewCount="33" Body="&lt;p&gt;Wikipedia describes a concept called &amp;quot;physiographic provinces&amp;quot;. If I understand right, geologists simply created lines on a map, to create clusters of places that are geologically similar.&lt;/p&gt;&#xA;&lt;p&gt;What I see missing from any articles on physiographic provinces, is what were the characteristics used to define any particular &amp;quot;physiographic province&amp;quot;. I am a secondary teacher and need to teach and prepare curriculum about the provinces that my state falls in, so I think if I knew what kinds of characteristics geologists looked at to create each province, I'd know which characteristics to teach the students about.&lt;/p&gt;&#xA;&lt;p&gt;Is there a list of characteristics that were used to create these groups of provinces?&lt;/p&gt;&#xA;" OwnerUserId="17645" LastEditorUserId="17645" LastEditDate="2021-11-23T13:11:57.750" LastActivityDate="2021-11-25T04:27:16.623" Title="What characteristics are considered when distinguishing a place based on physiographic provinces?" Tags="|geology|geography|terminology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23186" PostTypeId="2" ParentId="23178" CreationDate="2021-11-22T22:46:15.183" Score="1" Body="&lt;p&gt;The proposition of this question says nothing about the size of the domain, or how the domain has been discretized.  And yes, the numerical model will converge &lt;em&gt;if the necessary boundary conditions between model elements have been properly described.&lt;/em&gt;  In order to do this, all the dimensions of all elements must be properly characterized.  Presumably, a description of hydraulic head is desired in this exercise, and a visualization of how this change in head will evolve over time given various time- and pumping/recharge-driven scenarios.&lt;/p&gt;&#xA;&lt;p&gt;Appropriate description of the aquifer is the single most important aspect in developing the model.  Boundary conditions occur everywhere within the domain of the model and are maintained by appropriately accounting for the inflow and outflow across discretized model elements.  Presumably, this model was competently written.  Nevertheless, the elements may have been incorrectly characterized regarding their dimensions, or the mathematics may be in error.  Because the characterization given in the question provides no definition regarding scale, or a representation of the model output, the determination that the model did not converge may be in error.  The model may, in fact, have converged! The dimensional scaling of discretized elements in the model may be wrong.&lt;/p&gt;&#xA;&lt;p&gt;One of the easiest and best ways to determine if the characterization of the modeled domain is correct, is to set up an analogous analytic model for the same domain.  The Dupuit-Forscheimer relationship is quite strongly determined, and the outcome of such a model should be representative of the domain both in dimensions spatially and in time.  That outcome can be compared with the numerical model and differences noted.  One caution, though, is that the analytic model will have to appropriately use the method of images to simulate the no-flow boundaries that define the edges of the modeled domain.  This will entail an appropriate accounting of the images for pumping and recharge.&lt;/p&gt;&#xA;" OwnerUserId="24911" LastActivityDate="2021-11-22T22:46:15.183" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23189" PostTypeId="1" CreationDate="2021-11-23T06:44:33.027" Score="1" ViewCount="59" Body="&lt;p&gt;In &lt;a href=&quot;https://www.spaceperspective.com/neptune-one&quot; rel=&quot;nofollow noreferrer&quot;&gt;the image of Earth from a 100,000 ft on this site&lt;/a&gt; you can see abruptly divided layers of the atmosphere in different shades of blue. What are they, why do they have different shades and why can't we discern them from within the atmosphere like this?&lt;/p&gt;&#xA;&lt;p&gt;I guess the lowermost, light-blue layer is the atmosphere below the ozone layer, up to around 50,000 ft (15 km), essentially the troposphere and the tropopause. UV radiation is being blocked by the ozone layer above. The darker blue layer above then is probably the ozone layer, from 50,000 to ~115,000 ft (35 km); the abrupt change in color is due to the captured UV radiation I guess. The very dark blue-going-black area above it would be the area above the ozone layer, consisting of the uppermost part of the stratosphere, of the mesosphere aso.&lt;/p&gt;&#xA;&lt;p&gt;Are these abrupt changes in color really due to the ozone layer or is there a different reason, and why can't we recognize these different shades from within the atmosphere, but from space only?&lt;/p&gt;&#xA;" OwnerUserId="24914" LastActivityDate="2021-11-23T06:44:33.027" Title="What layers of the atmosphere are divided in this image by abrupt borders?" Tags="|atmosphere|ozone|stratosphere|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23191" PostTypeId="2" ParentId="23127" CreationDate="2021-11-23T15:11:23.337" Score="-1" Body="&lt;p&gt;The reason why humans are growing bigger (excluding any fat jokes) is because bigger humans must eat better, thus are more capable of surviving, and are also much better fighters (better strength/reach). This led to size being considered a favorable trait, leading humans to select larger mates and thus evolve to be larger. Once we started dominating the environment, we all grew larger, but the same instinct persists even today (just ask any guy under 6 feet).&lt;/p&gt;&#xA;&lt;p&gt;As for the dinosaurs, there was much more oxygen and CO2 in the atmosphere, so plants had more soil to grow in, the earth was hotter so more precipitation occurred, causing massive rainforests, and most importantly there was lots of O2/CO2 to breathe (plants breathe CO2, which gives them the majority of their mass).&lt;/p&gt;&#xA;&lt;p&gt;Over millions of years this C/O was sequestered underground, and things evolved to be smaller to compete as the earth starved of life-giving Oxygen and Carbon. Now we are putting it back in circulation, reversing this trend. However, this reversal causes changes, and as change is scary it is by default bad.&lt;/p&gt;&#xA;" OwnerUserId="24916" LastActivityDate="2021-11-23T15:11:23.337" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23192" PostTypeId="1" CreationDate="2021-11-23T20:11:37.617" Score="1" ViewCount="41" Body="&lt;p&gt;I am working with 13 dropsonde profiles that were launched during a field program. I have been attempting to create composite profiles of them using python, but I am a bit stuck. Here are the issues that I'm dealing with:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The altitudes at which each dropsonde began its descent and ended its descent are different for each dropsonde. In addition, the altitude profiles are different for each dropsonde and therefore have differing amounts of total data points&lt;/li&gt;&#xA;&lt;li&gt;Although each dropsonde transmitted data every 0.25 seconds, the data were not transmitted the same for each dropsonde. For example, the fill value for the dropsonde data is -9999, and that value occurred at the same or similar altitude as another dropsonde that did not have a -9999 fill value at the same or similar altitude.&lt;/li&gt;&#xA;&lt;li&gt;Since there are values missing in one dropsonde at the same or similar altitude levels as other dropsondes, the calculation of the composite profiles would be skewed, since some dropsondes transmitted data at the same altitude as each other, or only one dropsonde&#xA;transmitted data at a certain altitude.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Here is a sample of what the data look like:&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Time_Start&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;TimeFLStart&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Pressure&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Temperature&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;RH&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Speed&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Direction&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Latitude&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Longitude&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Altitude&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;GPS Altitude&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Dewpoint&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Uwnd&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Vwnd&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Ascent&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;73810.00&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;0.00&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;73810.25&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;0.25&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;73810.50&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;0.50&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;73810.75&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;0.75&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;73811.00&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;1.00&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;-9999&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;&#xA;&lt;p&gt;And here is a snippet of some of the code for two dropsondes:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import numpy as np&#xA;import pandas as pd&#xA;&#xA;# Read data&#xA;&#xA;dropsonde_2030 = pd.read_csv('~/Dropsonde_DC8_202108212030_RA.ict', skiprows = 103)&#xA;dropsonde_2058 = pd.read_csv('~/Dropsonde_DC8_202108212058_RA.ict', skiprows = 103)&#xA;&#xA;# Create variables for altitude and temperature profiles and mask the data. I sliced the altitude arrays at 0:2615 since the first array has a length of 2615.&#xA;&#xA;dropsonde_2030_alt  = dropsonde_2030['GPS Altitude'].values&#xA;dropsonde_2030_alt  = np.ma.masked_where(dropsonde_2030_alt  == -9999, dropsonde_2030_alt)&#xA;dropsonde_2030_alt  = np.array([dropsonde_2030_alt])&#xA;dropsonde_2030_alt  = dropsonde_2030_alt[0,0:2615]&#xA;dropsonde_2030_temp = np.array(dropsonde_2030['Temperature'].values)&#xA;dropsonde_2030_temp = np.ma.masked_where(dropsonde_2030_temp == -9.999E3, dropsonde_2030_temp)&#xA;&#xA;dropsonde_2058_alt  = dropsonde_2058['GPS Altitude'].values&#xA;dropsonde_2058_alt  = np.ma.masked_where(dropsonde_2058_alt  == -9999, dropsonde_2058_alt)&#xA;dropsonde_2058_alt  = np.array([dropsonde_2058_alt])&#xA;dropsonde_2058_alt  = dropsonde_2058_alt[0,0:2615]&#xA;dropsonde_2058_temp = dropsonde_2058['Temperature'].values&#xA;dropsonde_2058_temp = np.ma.masked_where(dropsonde_2058_temp == -9999, dropsonde_2058_temp)&#xA;&#xA;# Combine dropsondes together into one array&#xA;&#xA;combined = np.vstack((dropsonde_2030_alt, dropsonde_2058_alt)).T # has shape of (2615,2)&#xA;&#xA;# Compute the average altitude at each point &#xA;&#xA;means_all  = []&#xA;for i in range(len(combined)):&#xA;  for j in range(len(combined[i])):&#xA;    means = np.mean(combined[i][j])&#xA;    means_all.append(means)&#xA;means_all = np.array(means_all) # Convert list back to np.array&#xA;means_all_2d = np.reshape(means_all, (2615, 2)) # Convert back to 2d array in order to take the means along axis 1&#xA;means_alt = np.mean(means_all_2d, axis = 1) &#xA;means_alt = np.ma.masked_where(means_alt == -9999, means_alt) # Mask -9999 values&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Above, I tried to calculate the average altitude profile for the two dropsondes, but I think I may be overcomplicating it. I tried to create a nested for loop in order to calculate the means at each index, but the outputted means do not look correct.&lt;/p&gt;&#xA;&lt;p&gt;If anyone has an idea of what I should change, add, or delete, please let me know. Any feedback is greatly appreciated. Thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="20707" LastEditorUserId="18081" LastEditDate="2021-11-24T11:01:33.057" LastActivityDate="2021-11-24T11:01:33.057" Title="Creating composite dropsonde profiles?" Tags="|atmosphere|earth-observation|python|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23194" PostTypeId="1" AcceptedAnswerId="23197" CreationDate="2021-11-24T11:22:18.993" Score="8" ViewCount="2319" Body="&lt;p&gt;I am using data in a GIS application that shows some land or islands in areas where I would not expect such, or at least have never heard that there are islands.&#xA;How to find these in Google Earth? Do they have names?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/31eL3.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/31eL3.jpg&quot; alt=&quot;I marked the islands in question yellow&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24923" LastEditorUserId="222" LastEditDate="2021-11-25T15:37:34.687" LastActivityDate="2021-11-25T15:37:34.687" Title="Do these islands exist or are they technical artifacts?" Tags="|geography|atlantic|islands|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23195" PostTypeId="1" CreationDate="2021-11-24T14:02:15.640" Score="3" ViewCount="45" Body="&lt;p&gt;I would like to carry out a superficial analysis of a small number of CMIP6 models I downloaded from the ESGF. I'm thinking that a spatial correlation or Mean Square error between climatologies of historical observations and modelled historical would be useful. Are there any tools or open access code available to do this?&lt;/p&gt;&#xA;" OwnerUserId="24395" LastActivityDate="2021-11-24T14:02:15.640" Title="Are their any tools or code available to evaluate cmip6 models (r or matlab preferred)?" Tags="|climate-change|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23196" PostTypeId="1" AcceptedAnswerId="23201" CreationDate="2021-11-24T14:14:56.043" Score="1" ViewCount="526" Body="&lt;p&gt;At altitudes from 12-20 km (7-12.5 mi) above the midlatitudes the temperature remains constant with altitude (minus 56.5°C in the ISA). This part is usually considered to be in the stratosphere, but is there a special reason for that, or wouldn't it matter if the tropopause was set at the upper boundary of the isothermal layer rather than the lower one? There's another isothermal layer, the stratopause at 48-52 km (29.8-32.3 mi), here we set the stratopause simply at its center, to 50 km. Why isn't the tropopause set to the center of its isothermal layer as well, but on its lower boundary?&lt;/p&gt;&#xA;" OwnerUserId="24914" LastEditorUserId="24914" LastEditDate="2021-11-24T15:09:23.530" LastActivityDate="2021-11-25T07:33:33.283" Title="Why is the isothermal layer being considered a part of the stratosphere rather than the troposphere or being an independent layer?" Tags="|meteorology|atmosphere|temperature|troposphere|stratosphere|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23197" PostTypeId="2" ParentId="23194" CreationDate="2021-11-24T15:21:02.083" Score="12" Body="&lt;p&gt;At the risk of sounding like the old MS Paperclip... it looks like your data are on the &lt;a href=&quot;https://www.nature.com/articles/s41597-020-0453-3&quot; rel=&quot;noreferrer&quot;&gt;CRU TS&lt;/a&gt; land grid.  This grid is known to have some rogue land points, as mentioned by &lt;a href=&quot;https://doi.org/10.1002/2014WR015638&quot; rel=&quot;noreferrer&quot;&gt;Weedon et al (2014)&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The 211 of the 67,420 CRU grid boxes outside Antarctica used in the WFD are incorrectly designated as land. These were omitted from the WFDEI files; leaving 67,209 land points outside Antarctica plus 27,533 within (the grid boxes are not of equal area).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/g8T1I.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/g8T1I.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I've never seen a clear explanation of where they come from, but I recall they have associated elevations of zero.  I suspect that some of them are from moored buoys that were mis-characterized as land.  For example, the Bay of Biscay box is probably the Gascogne buoy described in &lt;a href=&quot;https://doi.org/10.1175/2010JTECHA1475.1&quot; rel=&quot;noreferrer&quot;&gt;Turton and Pethica (2010)&lt;/a&gt; and the group to the west is probably &lt;a href=&quot;https://www.ndbc.noaa.gov/station_page.php?station=62442&quot; rel=&quot;noreferrer&quot;&gt;Ocean Station PAP&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qDzTm.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qDzTm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2021-11-24T15:21:02.083" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="23198" PostTypeId="2" ParentId="6666" CreationDate="2021-11-24T16:04:40.273" Score="0" Body="&lt;p&gt;One cannot discount the fact that the northern islands&#xA;of Indonesia Timor island and Papua New Guinea are&#xA;very high precipitation areas.  It has been documented&#xA;that there is high groundwater movement under Sahul&#xA;shelf off Timor Island.  The same Sahul shelf is also&#xA;between Papua New Guinea and Australia.  Since there is high groundwater movement off of Timor Island there is&#xA;a high probability there is between Cape York and&#xA;Papua New Guinea shore line.  So GAB could be replenished by the Northern Islands of Timor and&#xA;Papua New Guinea.&lt;/p&gt;&#xA;" OwnerUserId="24926" LastActivityDate="2021-11-24T16:04:40.273" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23199" PostTypeId="2" ParentId="23185" CreationDate="2021-11-25T04:27:16.623" Score="1" Body="&lt;p&gt;&lt;em&gt;Topography&lt;/em&gt; probably the most distinctive characteristic defining a physiographic province.  Each physiographic province has a topographic character that is generally defined.  This does not mean the topography is all the same; there can be variation.  For instance, the Colorado Plateau has higher-elevation mesas with intermediate to lower elevation valleys. Geologically, these features are distinctive and similar. But the Colorado Plateau also has mountains - The San Juan Mountains - bordering on the southeast of the province.  These mountains are all distinctive Tertiary volcanoes, some of relatively immense proportions.  The only east-west mountain range in the United States is found on the northern boundary of the province.  These are the Uinta Mountains.  Rivers are typically in deep canyons; think Goose Necks of the San Juan.&lt;/p&gt;&#xA;&lt;p&gt;A comparison with the Rocky Mountains shows the mountains and upland areas are largely supported by granite.  The mountains are formed from granite ranges flanked by sedimentary rocks.  Rivers are formed in steep, upland glaciated valleys.&lt;/p&gt;&#xA;&lt;p&gt;At the eastern edge of the Rockies is seen the expansive Great Plains province, a place of completely different typography.  The Great Plains province has flat, gentle, rolling typography, with grasslands and broad river valleys.&lt;/p&gt;&#xA;&lt;p&gt;These are just some examples, without laboring the point.  Each province has its own distinctive typography.  A good place to look is the Cascade Ranges province. What is the distinctive topographic feature there? (Answer: Typically active volcanoes, such as Lassen Peak in California, or Mount Rainier, Washington, all consequent to the subduction of the Juan de Fuca tectonic plate.)&lt;/p&gt;&#xA;" OwnerUserId="24930" LastActivityDate="2021-11-25T04:27:16.623" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23200" PostTypeId="1" CreationDate="2021-11-25T07:04:34.083" Score="1" ViewCount="102" Body="&lt;p&gt;I tried Google BigQuery but it is at day level.&lt;/p&gt;&#xA;&lt;p&gt;Is there any source for hourly historical weather data for USA?&lt;/p&gt;&#xA;" OwnerUserId="24932" LastEditorUserId="18081" LastEditDate="2021-11-26T15:35:10.087" LastActivityDate="2021-12-01T21:03:20.013" Title="Hourly historical weather data for USA" Tags="|meteorology|" AnswerCount="4" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23201" PostTypeId="2" ParentId="23196" CreationDate="2021-11-25T07:33:33.283" Score="1" Body="&lt;p&gt;This is simply because of the way that the troposphere is defined and the fact that isothermal layers are of constant temperature. The troposphere has one defining characteristic; the air temperature drops with increased altitude. The isothermal layer is where that stops happening and temperatures remain stable with increased altitude, so the tropopause is at the base of it.&lt;/p&gt;&#xA;&lt;p&gt;The stratopause is different because it is defined as the point of maximum temperature of both the stratosphere and the mesosphere. It is traditionally represnted as a line placed in the middle of the upper stratospheric isothermal layer as the halfway mark between the two layers but in reality the entire isothermal layer is, by definition, the stratopause.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2021-11-25T07:33:33.283" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="23202" PostTypeId="2" ParentId="23200" CreationDate="2021-11-25T16:05:30.723" Score="1" Body="&lt;p&gt;Try the RAWS site at Western Regional Climate Center, &lt;a href=&quot;https://raws.dri.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.  When you visit the WRCC site, you will notice that the site is still under construction. Nevertheless, move your cursor over the state you wish data for, select that state, and an interactive map for that state will be displayed showing the available RAWS data sites from which you may choose.  An inventory of available data is then displayed for the chosen site.  Keep in mind that some Remote Automatic Weather Stations may have limited records, while others are voluminous.&lt;/p&gt;&#xA;&lt;p&gt;You may also wish to check this site at the University of Utah, &lt;a href=&quot;https://mesowest.utah.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. Simply select the state for which you wish to retrieve hourly data, select the site of interest, and review the available data. Note that several and various data series are available from which hourly data may be accessed.  A user account is required, though, to download data for a series longer than one day.&lt;/p&gt;&#xA;" OwnerUserId="24937" LastActivityDate="2021-11-25T16:05:30.723" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23203" PostTypeId="2" ParentId="23200" CreationDate="2021-11-25T16:41:37.893" Score="2" Body="&lt;p&gt;NCDC is a great resource for this type of stuff. &lt;a href=&quot;https://www.ncei.noaa.gov/metadata/geoportal/rest/metadata/item/gov.noaa.ncdc%3AC00532/html&quot; rel=&quot;nofollow noreferrer&quot;&gt;This data set&lt;/a&gt; should have exactly what you're looking for with hourly METAR reports from ASOS stations around the country. There's a ton of other data sets there but this should be closest to what you want.&lt;/p&gt;&#xA;" OwnerUserId="13660" LastActivityDate="2021-11-25T16:41:37.893" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23204" PostTypeId="1" AcceptedAnswerId="23205" CreationDate="2021-11-25T19:52:16.053" Score="1" ViewCount="849" Body="&lt;p&gt;I am trying to calculate total daily rainfall based on data from a tipping bucket rain gauge which is calibrated to a tip of 0.2mm. I have data giving the exact time that a tip is recorded and have summed the number of tips per day.&lt;/p&gt;&#xA;&lt;p&gt;I am getting myself confused when converting between mm and ml. I understand that the rainfall height is simply 0.2mm x the number of tips in a 24 hour period. Where I am getting confused is converting this number to total daily rainfall in ml. I am interested in looking at variations in runoff generation for some field-scale runoff plots. I have the area measurement for the rain gauge (214 cm²). Do I need to convert for the field area where the gauge is situated as well when calculating the total daily rainfall? I feel like it can't be as simple as whatever the rainfall height is (in mm) converted to ml.&lt;/p&gt;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="24940" LastActivityDate="2021-11-25T21:58:58.093" Title="Calculating total daily rainfall from a tipping bucket rain gauge" Tags="|meteorology|rainfall|rain|runoff|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23205" PostTypeId="2" ParentId="23204" CreationDate="2021-11-25T21:58:58.093" Score="1" Body="&lt;p&gt;You are on the right track.  Rain gauges measure rainfall as a linear measure.  Consequently, 2 mm of rainfall is the same as saying that the &lt;em&gt;measured depth&lt;/em&gt; of water that would have &lt;em&gt;accrued&lt;/em&gt; due to rainfall is 2 mm. You do not need to convert the rain gauge area because the rain gauge has been calibrated to give you the correct measured depth of rainfall as a linear measure, in this case, in mm.&lt;/p&gt;&#xA;&lt;p&gt;So you have this rain gauge in a field, say an agricultural field, of a known specific area. &lt;em&gt;The volume&lt;/em&gt; of the rainfall is simply the depth times the area.  To keep the units consistent, convert 2 mm to meters, and do the math.  Here is an example for a field 300 m by 200 m, using a 2 mm rainfall measured with your tipping bucket rain gauge -&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Field area           300 m  x  200 m   or   30000 sq meters&lt;/li&gt;&#xA;&lt;li&gt;rainfall             2/1000 meters&lt;/li&gt;&#xA;&lt;li&gt;Volume rainfall      30000 m x 2/1000 m  =  &lt;span class=&quot;math-container&quot;&gt;$60 m^3$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;This was a great question!&lt;/p&gt;&#xA;" OwnerUserId="24942" LastActivityDate="2021-11-25T21:58:58.093" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23206" PostTypeId="2" ParentId="20884" CreationDate="2021-11-26T15:27:15.133" Score="3" Body="&lt;p&gt;(This homework question is probably long overdue, but here is an answer for the sake of site statistics and future readers.)&lt;/p&gt;&#xA;&lt;p&gt;Magmatic rocks are further classified into extrusive rocks (emplaced at the surface) and plutonic rocks (emplaced in the crust). A magma of the same (silicic) composition can yield a granite if emplaced as a pluton, or a rhyolite if emplaced at the surface. So to answer the first part, you just have to look at the rock's name: if it's a rhyolite, then it was formed at the Earth's surface.&lt;/p&gt;&#xA;&lt;p&gt;As for the grain size, there is this classic diagram (here from &lt;a href=&quot;https://doi.org/10.1017/9781108654609&quot; rel=&quot;nofollow noreferrer&quot;&gt;Vernon 2018&lt;/a&gt;):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rMmxF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rMmxF.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The diagram shows that if you cool a magma quickly (high undercooling), you get a lot of nucleation (a nucleus is like a crystal embryo) but not much crystal growth, so you end up with lots of small crystals in the rock. On the contrary, if you cool a magma slowly (low undercooling) you get few nucleation but more crystal growth, so you end up with less crystals, but bigger ones. (And if you cool very fast you have neither and end up with a glass, i.e., obsidian.) So here the answer is B: &lt;strong&gt;if you have coarse grains, then the cooling was slow&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Note that the question is bit tricky because normally, as rhyolite is emplaced at the surface, it cools quickly hence have fine grains, while coarse grains is usually typical of granite, which cools slower in the crust...&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2021-11-26T15:27:15.133" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23207" PostTypeId="2" ParentId="20884" CreationDate="2021-11-26T16:54:14.460" Score="3" Body="&lt;p&gt;Rhyolite &lt;em&gt;by definition&lt;/em&gt; doesn’t have coarse grains.  A rock with the composition of rhyolite that is completely coarse grained is going to be a &lt;strong&gt;granite&lt;/strong&gt; or &lt;strong&gt;microgranite&lt;/strong&gt; of some sort.&lt;/p&gt;&#xA;&lt;p&gt;If what you are referring to are phenocrysts in the rhyolite (i.e. a rhyolite with porphyritic texture) or even crystals in a rhyolite tuff, then that is an indication that those crystals formed in the magma chamber and were suspended in the melt prior to extrusion of the rhyolite.&lt;/p&gt;&#xA;&lt;p&gt;So if this is a test or homework question, it’s at best poorly worded.  The answer is that larger grains in igneous rocks generally cool more slowly, deeper in the lithosphere.  It’s not so straightforward, though—crystal size is also affected by other factors like nucleation rate and growth rate, which are themselves dependent not only on time, but by characteristics of the crystal habit, available sites for nucleation, the fraction of and distribution of melt in a partial melt/crystal mush, the shape of a magma chamber or intrusion in which they initially nucleate, the bulk composition of the remaining melt fraction, pressure, and temperature.  But rhyolite by definition is an extrusive rock which is erupted at the surface, and cools quite quickly, relatively speaking.  As mentioned above, any phenocrysts in the rhyolite would themselves have formed more slowly in the magma chamber or conduit, within the earth, but the rhyolite itself, a fine-grained rock, is molten when extruded and cools quickly.&lt;/p&gt;&#xA;" OwnerUserId="24948" LastEditorUserId="24948" LastEditDate="2023-05-31T06:14:30.137" LastActivityDate="2023-05-31T06:14:30.137" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23208" PostTypeId="1" AcceptedAnswerId="23211" CreationDate="2021-11-26T17:25:02.910" Score="14" ViewCount="1193" Body="&lt;p&gt;A &lt;a href=&quot;https://www.cnn.com/2021/11/23/us/mammoth-tusk-discovery-at-bottom-of-the-ocean-trnd/index.html&quot; rel=&quot;noreferrer&quot;&gt;recently publicized&lt;/a&gt; discovery of a &lt;a href=&quot;https://en.wikipedia.org/wiki/Columbian_mammoth&quot; rel=&quot;noreferrer&quot;&gt;Columbian Mammoth&lt;/a&gt; tusk located well of the coast of California in quite deep water made me wonder if geological conditions 100,000 years ago can explain how it got to the location it was found at?&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Pilot Randy Prickett and scientist Steven Haddock, researchers with&#xA;Monterey Bay Aquarium Research Institute (MBARI), discovered a&#xA;Columbian mammoth tusk 185 miles offshore and 10,000 feet deep in the&#xA;ocean in 2019, the institution said in a news release.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;According to the &lt;a href=&quot;https://www.mbari.org/mammoth-tusk-discovery/&quot; rel=&quot;noreferrer&quot;&gt;Monterey Bay Aquarium Research Institute&lt;/a&gt;, the tusk portion is at least 100,000 years old:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The team believes it could be the oldest well-preserved mammoth tusk&#xA;recovered from this region of North America. Dating of the tusk is&#xA;being done by the UCSC Geochronology Lab led by Terrence Blackburn,&#xA;associate professor of Earth and planetary sciences. Blackburn&#xA;analyzed radioisotopes to show that the tusk is much more than 100,000&#xA;years old. “Our age estimate on the tusk is largely based on the&#xA;natural radioactive decay of certain uranium and thorium isotopes&#xA;imparted to the tusk from the ocean. If the tusk had been found on&#xA;land, deciphering its history would not be as straightforward,” said&#xA;Blackburn. Christopher Edwards and Patrick Drake will examine the&#xA;oceanographic currents to better pinpoint where the tusk originally&#xA;came from.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://news.ucsc.edu/2021/11/mammoth-tusk.html&quot; rel=&quot;noreferrer&quot;&gt;Another article&lt;/a&gt; I looked at mentioned they were exploring an underwater seamount formation with the ROV, so it looks like the approximate location might be about here:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/gEfaY.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gEfaY.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This looks well beyond any continental shelf or continuous undersea canyon type formations which might connect the location to the shoreline.&lt;/p&gt;&#xA;&lt;p&gt;So, is there a geological explanation for how this mammoth tusk might have ended up at this location?&lt;/p&gt;&#xA;" OwnerUserId="6057" LastEditorUserId="6057" LastEditDate="2021-11-27T16:52:36.633" LastActivityDate="2021-11-28T05:20:44.167" Title="Is there a geological explanation for the recent Mammoth tusk discovery 185 miles off the California coast?" Tags="|oceanography|plate-tectonics|sea-level|paleontology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23209" PostTypeId="1" AcceptedAnswerId="23210" CreationDate="2021-11-26T18:31:53.393" Score="3" ViewCount="157" Body="&lt;p&gt;I have heard it from many, many places that the big cities are drawing too much water from their aquifers, and then climate change will exacerbate that problem amongst a very many others. My city, London, has been said to face severe water shortages by 2040/2050, as will much of the planet. I do not know where to begin researching these statements rigorously, but I don’t have any faith that our governments are doing much to research the problem / take action against it and I find it very plausible that these statements are not too exaggerated.&lt;/p&gt;&#xA;&lt;p&gt;This is a very brief question, but ... just how severe (or hopefully someone can tell me how &lt;em&gt;preventable&lt;/em&gt;) is this problem?&lt;/p&gt;&#xA;" OwnerUserId="24949" LastActivityDate="2021-11-28T06:04:01.693" Title="What on Earth are we doing and can be done to prevent the projected (massive) water shortages?" Tags="|climate-change|water|resources|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23210" PostTypeId="2" ParentId="23209" CreationDate="2021-11-26T20:43:07.013" Score="3" Body="&lt;p&gt;To try to address current and future water shortage issues, some countries have implemented &lt;a href=&quot;https://www.dw.com/en/seeding-clouds-in-china/a-5213511&quot; rel=&quot;nofollow noreferrer&quot;&gt;cloud seeding&lt;/a&gt; programs to induce rainfall. Such countries include: China, the United States of America, Dubai, India, Venezuela, the United Arab Emirates.&lt;/p&gt;&#xA;&lt;p&gt;Many countries, over the years have experimented with cloud seeding, with varying degrees of success, such as in &lt;a href=&quot;http://www.cmar.csiro.au/e-print/open/cloud.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Australia&lt;/a&gt;, where it is success in some parts of the country, but not others.&lt;/p&gt;&#xA;&lt;p&gt;Some jurisdictions have established &lt;a href=&quot;https://en.wikipedia.org/wiki/Desalination&quot; rel=&quot;nofollow noreferrer&quot;&gt;water desalination&lt;/a&gt; plants to supplement existing supplies. Such schemes can be expanded.&lt;/p&gt;&#xA;&lt;p&gt;In addition to such measures, water conservation programs, to reduce water consumption, form part of the strategies. Such programs include reducing domestic water usage in the bathroom &amp;amp; laundry,by reducing bathing times and the implementation of &lt;a href=&quot;https://en.wikipedia.org/wiki/Dual_flush_toilet&quot; rel=&quot;nofollow noreferrer&quot;&gt;dual flush toilets&lt;/a&gt;. Redirecting rain water from household gutters to storage tanks so the water can be used on gardens.&lt;/p&gt;&#xA;&lt;p&gt;Gray water systems have been used on an industrial scale in Mexico and are being introduced on a domestic scale elsewhere.&lt;/p&gt;&#xA;&lt;p&gt;What strategy gets used where, will depend on what is most appropriate for each locality.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;Edit&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;In 2018 the BBC reported on &lt;a href=&quot;https://www.bbc.com/news/world-42982959&quot; rel=&quot;nofollow noreferrer&quot;&gt;11 cities most likely to run out of drinking water&lt;/a&gt;, London was one of them. The others were Sao Paulo, Bangalore, Beijing, Cairo, Jakarta, Moscow, Istanbul, Mexico City, Tokyo &amp;amp; Miami.&lt;/p&gt;&#xA;&lt;p&gt;After enduring a drought, in which water levels started to decline in 2015, &lt;a href=&quot;https://en.wikipedia.org/wiki/Cape_Town_water_crisis&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cape Town nearly ran out of water&lt;/a&gt; in 2018, where dam capacity reached 15 to 30 percent. The city was &lt;a href=&quot;https://www.weforum.org/agenda/2019/08/cape-town-was-90-days-away-from-running-out-of-water-heres-how-it-averted-the-crisis/&quot; rel=&quot;nofollow noreferrer&quot;&gt;90 days away from having no water&lt;/a&gt;. Cape Town got lucky, heavy rains began falling in June 2018, averting the crisis and by September 2018 the dams were close to 70 percent full. In 2020, with successive rain the dams were 95 percent full.&lt;/p&gt;&#xA;&lt;p&gt;As part of the strategy to ensure more water &lt;a href=&quot;https://time.com/cape-town-south-africa-water-crisis/&quot; rel=&quot;nofollow noreferrer&quot;&gt;a desalination plant was built&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;As a result of the &lt;a href=&quot;https://en.wikipedia.org/wiki/2000s_Australian_drought&quot; rel=&quot;nofollow noreferrer&quot;&gt;Millennium Drought in Australia&lt;/a&gt; from 1997 to 2009, &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_desalination_plants_in_Australia&quot; rel=&quot;nofollow noreferrer&quot;&gt;six major desalination plants were constructed&lt;/a&gt; between 2006 and 2012. These plants have a capacities ranging between 125 ML per day to 410 ML per day (45 GL/yr to 150 GL/yr). Another 18 additional smaller plants were also constructed and another 6 are planned or being constructed.&lt;/p&gt;&#xA;&lt;p&gt;Britain is an island nation. It has easy and readily available access to sea water. If the will and money were there, desalination plants could easily be constructed to supply any part of Britain. The other problem that will need to be solved if such plants were to be construction is what energy source will be used to allow the plants to operate. The desalination plant in Perth, Western Australia initially had a dedicated &lt;a href=&quot;https://www.researchgate.net/publication/228491362_Low_energy_consumption_in_the_Perth_seawater_desalination_plant&quot; rel=&quot;nofollow noreferrer&quot;&gt;wind farm&lt;/a&gt;. It may still be operating using renewable energy sources for its full production.&lt;/p&gt;&#xA;&lt;p&gt;What happens with London's water supply issues will depend on what the government and water authorities do and how timely they are about it.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-11-27T02:52:49.860" LastActivityDate="2021-11-27T02:52:49.860" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23211" PostTypeId="2" ParentId="23208" CreationDate="2021-11-26T23:30:08.103" Score="22" Body="&lt;ol&gt;&#xA;&lt;li&gt;The mammoth probably died on land.&lt;/li&gt;&#xA;&lt;li&gt;Its remains got picked up by a glacier.&lt;/li&gt;&#xA;&lt;li&gt;The glacier carried the tusk down to the sea.&lt;/li&gt;&#xA;&lt;li&gt;Eventually, the ice containing the tusk broke off as an iceberg.&lt;/li&gt;&#xA;&lt;li&gt;The iceberg floated out to sea..&lt;/li&gt;&#xA;&lt;li&gt;When it got near to where the researchers found the tusk, the ice around the tusk melted and dropped it into the water, where it sank to the bottom.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;When this happens to a rock a glacier picks up, it is called a &amp;quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Dropstone&quot; rel=&quot;noreferrer&quot;&gt;dropstone&lt;/a&gt;&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;During glacial maxima, icebergs can survive much farther south than now. The presence of dropstones in what were supposedly equatorial sediments led to the theory of a Snowball Earth a billion or so years ago.&lt;/p&gt;&#xA;&lt;p&gt;Based upon CO&lt;sub&gt;2&lt;/sub&gt; data, 100,000 years ago, the Earth was working its way into the most recent glacial maximum, called the &lt;a href=&quot;https://en.wikipedia.org/wiki/Wisconsin_glaciation&quot; rel=&quot;noreferrer&quot;&gt;Wisconsin glaciation&lt;/a&gt; in North America  ( the likely source of this iceberg).&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/c/c9/Co2_glacial_cycles_800k.png&quot; alt=&quot;Glacial maxima graph&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Co2_glacial_cycles_800k.png&quot; rel=&quot;noreferrer&quot;&gt;Wikimedia Commons&lt;/a&gt;, Author Tom Ruen, &lt;a href=&quot;https://creativecommons.org/licenses/by-sa/3.0/deed.en&quot; rel=&quot;noreferrer&quot;&gt;CC BY-SA 3.0&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Notice that the article did not call the tusk a &amp;quot;fossil&amp;quot;.  You can only call it that after a specific process of mineralization after being buried in sediment.  They might very well have found original ivory from the mammoth.&lt;/p&gt;&#xA;&lt;p&gt;But this is not necessary. There are two ways the tusk got into the glacier:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The carcass was buried in sediment and some or all of its skeleton, including the tusk, became fossilized. Later, the glacier picked up the rock containing the fossil.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The mammoth died on top of the glacier, the carcass was buried in snow and more glacier may have built itself on top.  This is the most likely scenario if they found original ivory.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2021-11-27T00:13:04.567" LastActivityDate="2021-11-27T00:13:04.567" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="23212" PostTypeId="2" ParentId="23200" CreationDate="2021-11-26T23:58:38.293" Score="1" Body="&lt;p&gt;If you're just wanting to look up specific days when needed, it may wind up being easiest to use Weather Underground's historic data... go to wunderground.com, enter your location, then choose history:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FGlA4m.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FGlA4m.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;and then there is a basic graph of the day, and additional readout of hourly observations further down the page.  I usually find WU a solid option if looking up a day.  For larger datasets to run statistical analysis or algorithms on, you'd need something with more flexibility to download data.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2021-11-26T23:58:38.293" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23213" PostTypeId="2" ParentId="23182" CreationDate="2021-11-27T10:45:09.733" Score="1" Body="&lt;p&gt;Not sure about a model you can play with, but there are some very interesting videos of models here:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/results?search_query=landscape+erosion+model&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/results?search_query=landscape+erosion+model&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-11-27T10:45:09.733" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23214" PostTypeId="2" ParentId="23164" CreationDate="2021-11-27T10:50:35.923" Score="1" Body="&lt;p&gt;Just to add to the other answers,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;If it's mostly water vapor in the gas, then when it cools, the pumice&#xA;holes would contain liquid water, &lt;strong&gt;albeit small amounts compared to the&#xA;size of the vesicles.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is actually a very important point.&lt;/p&gt;&#xA;&lt;p&gt;When the magma erupted, the vesicle contained very low density H&lt;sub&gt;2&lt;/sub&gt;O gas.&lt;/p&gt;&#xA;&lt;p&gt;Assuming the vesicle remains closed somehow and isolated from the outside, cooling down of the vesicle would not necessarily lead to the formation of liquid water. The total amount of molecules inside the vesicle if fixed, and the drop in temperature leads to a very low inside pressure. The total density remains the same, which is much lower than the density of liquid water. Therefore, pumice floats.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-11-27T10:50:35.923" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23215" PostTypeId="2" ParentId="23107" CreationDate="2021-11-27T11:07:35.893" Score="3" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;What is the role of trace elements in magmatic crystallization?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;They don't really have a role in magmatic crystallisation. Trace elements are useful because they are (sometimes) more sensitive to changes in crystallisation conditions, when they are measured.&lt;/p&gt;&#xA;&lt;p&gt;For example, a basalt crystallising plagioclase wouldn't change its Al, Ca, Na, and Si contents too much. They will change a bit, but nothing serious. On the other hand, strontium and europium are two trace elements that are extremely compatible in plagioclase. Seeing a rock with a strong depletion of Eu and Sr compared to average crust (for example) indicates that plagioclase has crystallised in its crystallisation history. This is less obvious when considering only major elements (although can be deduced by the experienced petrologist).&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-11-27T11:07:35.893" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23216" PostTypeId="1" CreationDate="2021-11-27T14:52:03.033" Score="4" ViewCount="508" Body="&lt;p&gt;Looking around on Google Maps, one can zoom in on the banks of the Oder river between Germany and Poland and find quite an extensive series of curious repeating land features along much of the river banks that resemble bones along a spine, for example at &lt;a href=&quot;https://www.google.com/maps/@52.382379,14.5466943,523m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;52°22'56.1&amp;quot;N 14°32'46.2&amp;quot;E&lt;/a&gt; and &lt;a href=&quot;https://www.google.com/maps/@52.0961588,14.7157618,1125m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;52°05'43.6&amp;quot;N 14°43'00.1&amp;quot;E&lt;/a&gt;. What are these land features and how are they formed?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IDotW.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IDotW.png&quot; alt=&quot;Second picture&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24955" LastEditorUserId="6298" LastEditDate="2022-02-06T17:24:49.953" LastActivityDate="2022-02-06T17:24:49.953" Title="What are these 'spine' land features on the banks of the Oder river?" Tags="|hydrology|rivers|topography|satellite-oddities|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23217" PostTypeId="2" ParentId="23216" CreationDate="2021-11-27T15:11:19.167" Score="8" Body="&lt;p&gt;River Groynes or &lt;a href=&quot;https://en.wikipedia.org/wiki/Wing_dam&quot; rel=&quot;noreferrer&quot;&gt;Wing dams&lt;/a&gt; which help to maintain a navigable channel by increasing river scour along the channel for shipping, reducing the need for dredging. They may also help reduce ice jamming.&lt;/p&gt;&#xA;" OwnerUserId="140" LastActivityDate="2021-11-27T15:11:19.167" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23219" PostTypeId="2" ParentId="23209" CreationDate="2021-11-28T06:04:01.693" Score="1" Body="&lt;p&gt;Build desalination plants, build nuclear plants to run them.  supposed water wars of the future will never erupt. Water is too heavy and dense a substance. A gallon of water weighs over 8 pounds, so transporting it accounts for most of the costs, so the idea of these Mad Max style thugs running off with water jugs is ridiculous, they would have to drink a lot of it sweating from the workout carrying it. It's not cost effective to do it in the long run compared to spending the money/resources on developing new supplies of potable water. A months worth of fighting between Israel and neighboring nations over water sources would be more costly than if Israel built several desalination plants and ran them for a year. Human activity consumed 3000 cubic kilometers of water in the year 2000, up from 600 cubic km in 1900. Yet the world contains 1.38 billion cubic kilometers. Future demands for water coincide with a future growing GDP, water access and cleanliness will increase in the future not decrease. Desalination is expensive no doubt and recycling waste water is less expensive than the latter but more expensive than traditional water, but the costs are becoming more competitive, desalination costs have declined by half in the last ten years and no doubt will decline even further in the next decade.&lt;/p&gt;&#xA;&lt;p&gt;The demand for what was considered a scarce resource led to the development of an economical way of extracting it or substitutes.&lt;/p&gt;&#xA;&lt;p&gt;Example: In the 1970?s and 80s, computer and telecommunications was rapidly growing requiring huge demand for copper to wire the world. Fears regarding copper price surges and monopolies hoarding stockpiles selling to select few. But by the 90's copper prices declined due to the invention of optical fiber replacing copper for the telecommunications market and millions of miles strewn across the country and around the world in far greater excess than copper might have provided. Being largely made of glass (i.e sand) is not a strategic resource.....&lt;/p&gt;&#xA;&lt;p&gt;Water cleansing technologies. There's an entire host of various water tech that can be scaled large scale or individual.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-11-28T06:04:01.693" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23220" PostTypeId="1" AcceptedAnswerId="23222" CreationDate="2021-11-28T14:26:52.107" Score="6" ViewCount="3212" Body="&lt;p&gt;Once in a while aspiring people aim to drill through the Earth's crust to reach the mantle, but why do they want that when the mantle is actually on or very close to the surface in volcano craters? Can't scientists just use volcano craters for researching the mantle rather than drilling miles and miles through the surface elsewhere?&lt;/p&gt;&#xA;" OwnerUserId="24914" LastActivityDate="2021-11-28T22:58:50.090" Title="If people aim to reach the mantle, why don't they just use volcano craters?" Tags="|volcanology|crust|mantle|drilling|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23221" PostTypeId="2" ParentId="23220" CreationDate="2021-11-28T19:08:27.340" Score="1" Body="&lt;p&gt;I am not a geologist, but my understanding is as follows: volcanoes may be felsic or mafic. The latter type gets its 'fuel' from hotspots from within the mantle. These volcanoes are located at plate boundaries, where the crust is thinner.&#xA;If the question is 'why can't we send a probe down such a hotspot volcano into the mantle' - I'm not sure why that'd be easier than just drilling into the oceanic crust, where the mantle is a few km's beneath. After all, oil wells are drilled far deeper than that (though they tend to be located near the continental shelf where there's an accretionary wedge of mesozoic detritus).&lt;/p&gt;&#xA;" OwnerUserId="21109" LastActivityDate="2021-11-28T19:08:27.340" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23222" PostTypeId="2" ParentId="23220" CreationDate="2021-11-28T22:58:50.090" Score="14" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;why don't they just use volcano craters?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Because volcano craters don't go to the mantle.&lt;/p&gt;&#xA;&lt;p&gt;Here's a sketch of how the crust, mantle, and volcanoes look like:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BZQGT.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BZQGT.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Tan colour is crust, orange is mantle. Your question may come from the misconception that the mantle is molten, but it is actually not. It's solid, except for very localised cases where the mantle &lt;em&gt;is&lt;/em&gt; molten (see diagram for examples). This magma then rises through weaknesses or cracks in the solid crust to reach the surface.&lt;/p&gt;&#xA;&lt;p&gt;Drilling through volcanoes will only give you information on the shallow plumbing of the magmatic system through the crust, and not much on the mantle.&lt;/p&gt;&#xA;&lt;p&gt;There are places where the mantle is very shallow, for example in oceanic spreading ridges, but those are active magmatic zones and drilling through liquid hot magma is not something that's feasible.&lt;/p&gt;&#xA;&lt;p&gt;Finally, there are places where mantle rocks have actually been exposed on thee surface, such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Ophiolite&quot; rel=&quot;noreferrer&quot;&gt;ophiolites&lt;/a&gt;, but these are probably exposed because the mantle there is slightly unusual. It provides only limited information on the more common and deeply-buried type of mantle that's elsewhere.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-11-28T22:58:50.090" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23223" PostTypeId="1" CreationDate="2021-11-28T23:22:54.403" Score="5" ViewCount="55" Body="&lt;p&gt;My 13 yr old kid is studying the water cycle and has raised me some question I  don't have answers to regarding how the salinity levels of the oceans are kept constant (over very long period of time)&lt;/p&gt;&#xA;&lt;p&gt;Q1: How is salinity maintained constant in the oceans?&lt;/p&gt;&#xA;&lt;p&gt;His reasoning is as follow:&lt;/p&gt;&#xA;&lt;p&gt;(1) salts stays in the oceans while water evaporates&#xA;(2) fresh waters transport salts from the rocks&lt;/p&gt;&#xA;&lt;p&gt;If (2) adds more salts, and (1) doesn't remove salts, shouldn't salinity increase over time? (even if it's a very long period of time)&lt;/p&gt;&#xA;&lt;p&gt;Q2:  is there not a (very long) time when there won't be anymore salts to &amp;quot;take&amp;quot; from the rocks and the ground?&lt;/p&gt;&#xA;&lt;p&gt;How is that supply renewed over time?&lt;/p&gt;&#xA;&lt;p&gt;Is there some sort of a salts cycle that somehow takes away salts from the oceans and adds them back into the ground/rocks?&lt;/p&gt;&#xA;&lt;p&gt;I was thinking aquatic organisms take salts into their body, we eat them, we die, our body goes back into the ground... But, to mean, that does sound really convincing. Also living things decomposition maybe?&lt;/p&gt;&#xA;" OwnerUserId="24963" LastActivityDate="2021-11-28T23:22:54.403" Title="Salinity balance in the oceans, is it increasing over time?" Tags="|oceanography|water|rivers|salinity|" AnswerCount="0" CommentCount="4" ClosedDate="2021-12-03T19:57:30.400" ContentLicense="CC BY-SA 4.0" />
  <row Id="23225" PostTypeId="2" ParentId="22513" CreationDate="2021-11-29T13:56:12.487" Score="3" Body="&lt;p&gt;I have used the GEM magnetometers for 25 years as a professional geophysicist.&lt;br /&gt;&#xA;You can use the total field intensity of an IGRF model, or you can use the average value of all of the readings of the base station mag.&#xA;For example you can use the &lt;a href=&quot;https://www.ngdc.noaa.gov/geomag/calculators/magcalc.shtml#igrfwmm&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA online service&lt;/a&gt;.  Just enter the date and latitude and longitude, and you will get the magnetic field parameters.&lt;/p&gt;&#xA;&lt;p&gt;Either way, don't change the value and don't move the base station during the survey.&lt;br /&gt;&#xA;That being said, the &amp;quot;datum&amp;quot; entered into the Gem magnetometer is not used in the diurnal corrections. During post processing, the user overrides that value when diurnally correcting using GemlinkW software.&lt;br /&gt;&#xA;So no need to worry about the datum you enter into the mag. Still, it is still useful know the magnetic field, as this is used for tuning the magnetometer. But, that is another story.&lt;/p&gt;&#xA;" OwnerUserId="24966" LastEditorUserId="6298" LastEditDate="2022-04-30T20:24:38.063" LastActivityDate="2022-04-30T20:24:38.063" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23226" PostTypeId="2" ParentId="22451" CreationDate="2021-11-29T17:39:09.290" Score="1" Body="&lt;p&gt;Measurements have been made of the Earth's magnetic field more or less continuously since about 1840. Some measurements even go back to the 1500s, for example at Greenwich in London. If we look at the trend in the strength of the magnetic field over this time (for example the so-called 'dipole moment' shown in the graph below) we can see a downward trend. Indeed projecting this forward in time would suggest zero dipole moment in about 1500-1600 years time. This is one reason why some people believe the field may be in the early stages of a reversal. We also know from studies of the magnetisation of minerals in ancient clay pots that the Earth's magnetic field was approximately twice as strong in Roman times as it is now.&lt;/p&gt;&#xA;&lt;p&gt;(from &lt;a href=&quot;http://www.geomag.bgs.ac.uk/education/reversals.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.geomag.bgs.ac.uk/education/reversals.html&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;If you look into magnetic field calculators (IGRF), you will see that they are not valid for predicting total field strength even for a few years from now&lt;/p&gt;&#xA;" OwnerUserId="24966" LastActivityDate="2021-11-29T17:39:09.290" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23227" PostTypeId="1" CreationDate="2021-11-29T21:36:18.477" Score="6" ViewCount="140" Body="&lt;p&gt;I'm in the market for a new automated weather station and of course there's a glut of them on the internet. I mostly will be using the data for myself and my own amusement but do plan to submit measurements of temperature and wind speeds to the local NWS station for special weather events. Because of this, I want to make sure I'm using a station that is as accurate as can be.&lt;/p&gt;&#xA;&lt;p&gt;I know the that the WMO has siting recommendations and those will be followed but I'm having trouble finding about &lt;strong&gt;instrument certification or acceptability&lt;/strong&gt;. Is there such a thing or do I have to simply take the manufacturers at their word?&lt;/p&gt;&#xA;" OwnerUserId="13660" LastEditorUserId="22648" LastEditDate="2021-12-02T20:40:18.420" LastActivityDate="2022-09-12T14:45:36.777" Title="Is there a certification process for automated weather stations?" Tags="|meteorology|measurements|instrumentation|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23228" PostTypeId="1" AcceptedAnswerId="23230" CreationDate="2021-11-30T14:50:34.903" Score="4" ViewCount="141" Body="&lt;p&gt;I would like to understand to view the health of a glacier using optical or SAR data. What season would be the best for observation? Is the ablation season better or the accumulation season? More specifically I am targeting the southern slope of the Himalayan belt in India/Nepal.&lt;/p&gt;&#xA;" OwnerUserId="24972" LastEditorUserId="2470" LastEditDate="2021-11-30T15:47:39.187" LastActivityDate="2021-11-30T18:10:01.970" Title="Remote sensing of glaciers, season for data collection" Tags="|glaciology|remote-sensing|glaciation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23229" PostTypeId="2" ParentId="23182" CreationDate="2021-11-30T17:48:48.720" Score="6" Body="&lt;p&gt;I guess you are talking about subaerial (as opposed to submarine) canyons, and are mostly thinking of numerical (as opposed to physical) models.&lt;/p&gt;&#xA;&lt;p&gt;I expect there are numerical models suitable for submarine application, but I haven't looked for them. There are physical models of rivers too, but I think they are better suited to modeling 'soft' sedimentary systems like deltas, floodplains, etc.&lt;/p&gt;&#xA;&lt;p&gt;Here are some examples of numerical models in Python, starting with the research-grade ones (but if it was me I'd probably start with the ones I've thrown at the end):&lt;/p&gt;&#xA;&lt;h4&gt;PyBadlands&lt;/h4&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://raw.githubusercontent.com/badlands-model/badlands/master/badlands/docs/img/view.jpg&quot; alt=&quot;Sketch of Badlands models&quot; /&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;an open-source python-based framework that allows for evaluation of sediment transport, landscape dynamics and sedimentary basins evolution under the influence of climate, sea waves and tectonics&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5896951/&quot; rel=&quot;noreferrer&quot;&gt;Read the paper.&lt;/a&gt; &lt;a href=&quot;https://github.com/badlands-model/badlands&quot; rel=&quot;noreferrer&quot;&gt;Get the code.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;h4&gt;Landlab&lt;/h4&gt;&#xA;&lt;p&gt;This is a high-level toolkit for building models, but their docs point to all sorts of examples, several of which have to do with landscape evolution. For example, see Terrainbento and SPACE, below.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://landlab.github.io/#/&quot; rel=&quot;noreferrer&quot;&gt;Check out the website.&lt;/a&gt; &lt;a href=&quot;https://landlab.readthedocs.io/en/latest/_downloads/a4993af91f623377252d7bdb27fae60f/EGU_poster_2016.pdf&quot; rel=&quot;noreferrer&quot;&gt;Read a nice poster.&lt;/a&gt;&lt;a href=&quot;https://github.com/landlab/landlab&quot; rel=&quot;noreferrer&quot;&gt;Get the code.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;h4&gt;Terrainbento&lt;/h4&gt;&#xA;&lt;p&gt;This package builds on Landlab (above) to compare a large number of different Earth surface modelling strategies.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://gmd.copernicus.org/articles/12/1267/2019/&quot; rel=&quot;noreferrer&quot;&gt;Read the paper.&lt;/a&gt; &lt;a href=&quot;https://github.com/TerrainBento/terrainbento&quot; rel=&quot;noreferrer&quot;&gt;Get the code.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;h4&gt;SPACE&lt;/h4&gt;&#xA;&lt;p&gt;Another package that builds on Landlab, this time to study the simultaneous modeling of alluvial and bedrock erosion and transport.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://gmd.copernicus.org/articles/10/4577/2017/&quot; rel=&quot;noreferrer&quot;&gt;Read the paper.&lt;/a&gt; &lt;a href=&quot;https://github.com/cmshobe/pub_shobe_etal_GMD&quot; rel=&quot;noreferrer&quot;&gt;Get the code.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;h4&gt;Some others I've come across:&lt;/h4&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;An interactive model: &lt;a href=&quot;https://github.com/fastscape-lem/ipyfastscape&quot; rel=&quot;noreferrer&quot;&gt;https://github.com/fastscape-lem/ipyfastscape&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;A simple model: &lt;a href=&quot;https://github.com/johnjarmitage/flem&quot; rel=&quot;noreferrer&quot;&gt;https://github.com/johnjarmitage/flem&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;A simple model, from scratch: &lt;a href=&quot;https://github.com/mtb-za/landscape_evolution_short_course/blob/master/notebooks/FastScape.ipynb&quot; rel=&quot;noreferrer&quot;&gt;https://github.com/mtb-za/landscape_evolution_short_course/blob/master/notebooks/FastScape.ipynb&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;A global model (!): &lt;a href=&quot;https://github.com/Geodels/gospl&quot; rel=&quot;noreferrer&quot;&gt;https://github.com/Geodels/gospl&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2021-11-30T17:48:48.720" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23230" PostTypeId="2" ParentId="23228" CreationDate="2021-11-30T18:10:01.970" Score="7" Body="&lt;p&gt;Looking around at some random articles, for example &lt;a href=&quot;https://www.nps.gov/articles/glacier-monitoring-techniques.htm&quot; rel=&quot;noreferrer&quot;&gt;Karpilo 2009&lt;/a&gt;, &lt;a href=&quot;https://tc.copernicus.org/articles/15/3699/2021/tc-15-3699-2021-discussion.html&quot; rel=&quot;noreferrer&quot;&gt;Geissler et al 2021&lt;/a&gt;, &lt;a href=&quot;https://www.nature.com/articles/s41598-019-41657-5&quot; rel=&quot;noreferrer&quot;&gt;Litt et al. 2019&lt;/a&gt;, and &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3675549/&quot; rel=&quot;noreferrer&quot;&gt;Racoviteanu et al 2008&lt;/a&gt; my impression is that researchers primarily use images of the glacier taken near the end of the ablation season. (Apart from anything else, I imagine it's just the best time to see the edges and the details of the glacier.)&lt;/p&gt;&#xA;&lt;p&gt;The last paper in that list (Racoviteanu et al 2008) says they acquired data both at the end of the accumulation season and the ablation season. But they also say this:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Scenes acquired at the end of the ablation season are useful to identify the end-of-summer snowline altitude (SLA), considered to be directly related to variations in a glacier's mass balance&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.antarcticglaciers.org/glacier-processes/mass-balance/introduction-glacier-mass-balance/&quot; rel=&quot;noreferrer&quot;&gt;This page&lt;/a&gt; adds:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The snowline at the end of the summer season is often used to demarcate the equilibrium line on satellite images of glaciers.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2021-11-30T18:10:01.970" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23231" PostTypeId="1" CreationDate="2021-11-30T22:21:34.470" Score="18" ViewCount="5461" Body="&lt;p&gt;Yesterday during the day, inside my house it was 16% relative humidity. Outside it was 69% relative humidity and cold, around 35 degrees Farenheit. It is always 72 degrees Farenheit inside the house.&lt;/p&gt;&#xA;&lt;p&gt;During the warmer months the humidity in the house never goes below 35% relative humidity.&lt;/p&gt;&#xA;&lt;p&gt;So, it appears that somehow the outdoor temperature is affecting the relative humidity inside the house. How could this be?&lt;/p&gt;&#xA;" OwnerUserId="2491" LastEditorUserId="22648" LastEditDate="2021-12-02T20:40:31.767" LastActivityDate="2021-12-04T20:38:43.160" Title="Why would it be drier indoors during the winter vs the summer?" Tags="|temperature|humidity|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23232" PostTypeId="2" ParentId="23231" CreationDate="2021-11-30T23:30:01.567" Score="14" Body="&lt;p&gt;Because cooling air tends to take out moisture, while heating air doesn't change the actual moisture levels.&lt;br /&gt;&#xA;When air gets colder, it can't &amp;quot;hold&amp;quot; as much water vapor (lower saturation vapor pressure).&lt;br /&gt;&#xA;When air gets warmer, it can &amp;quot;hold&amp;quot; more water vapor (higher saturation vapor pressure).&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;So when air cools into the 30s °F, that drops the limit of moisture.  Then you heat it to the 70s, it still has that lower limit on moisture (the dew point can't be higher than the 30s).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Whereas when the summer airmass heats into the 80s, 90s, and beyond outside, that airmass isn't changing moisture.  When you cool it down on hot days, it still basically has its original ceiling limit (the dew point is whatever it was beforehand in the summer... which varies by location/airmass, but in reasonably moist regions like the eastern US and Europe, is usually up in like the 50s/60s/70s)&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;So your 72 °F in the summer will have dew points in like the 60s and so the ratio of actual to possible moisture is quite high, higher relative humidity... but in winter, your 72 °F will have dew points down in like the 20s or 30s or lower = lower relative humidity.&lt;/p&gt;&#xA;&lt;p&gt;(Dew point is really reflected more by the &lt;em&gt;lowest&lt;/em&gt; temperature in the day.  So if it's 30 °F outside in the daytime, but 10 °F at night... the 10 °F is the ceiling limit of the dew point of that air mass.  Likewise, if it's 90 °F during the daytime, but 65 °F at night, the dew point is capped around 65 °F.  But that's quite moist compared to winter air masses)&lt;/p&gt;&#xA;&lt;p&gt;(Unlike a house heater, quick major outdoor warmups are driven by warm fronts/warm air advection, which tend to bring in a different airmass, pulled in from more tropical regions, where the air also has also had plenty of time to evaporate moisture into it.  So not the same dryness.)&lt;/p&gt;&#xA;&lt;p&gt;(And air outdoors inevitably infiltrates/mixes indoors over time.  So that colder, drier air will eventually come inside.  You'll heat it, but it still doesn't have the moisture in it that the summertime air does.&lt;br /&gt;&#xA;...&lt;br /&gt;&#xA;Plus even apart from that, with it quite cold outside and warm and moist inside, the windows and other boundaries will cause the inside air touching it to condense because the surfaces get cold.  Conservation of mass suggests it'd generally reevapoprate when warmer [unless you clean it up], but given most areas get cold regularly during the winter, the &amp;quot;puddle&amp;quot; would tend to be a pretty permanent feature if your inside warm air managed to be moist enough [try steaming some vegetables for a while, or running a humidifier, and you'll see this... also the same idea as the condensation that forms on the outside of a cold drink bottle/cup].  Your walls may even get damp if the temperature difference is great enough.  All that liquid water is moisture taken out of the air.)&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2021-12-04T20:38:43.160" LastActivityDate="2021-12-04T20:38:43.160" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23234" PostTypeId="2" ParentId="23231" CreationDate="2021-12-01T10:10:31.237" Score="11" Body="&lt;p&gt;A &lt;a href=&quot;https://en.wikipedia.org/wiki/Psychrometrics#Psychrometric_charts&quot; rel=&quot;noreferrer&quot;&gt;psychrometric chart&lt;/a&gt; is very useful for those kind of calculations.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Psychrometrics#/media/File:PsychrometricChart.SeaLevel.SI.svg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kuvLY.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;There is a lot of information and the chart looks overwhelming at first. You can click on the charts to see a larger version.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;35°F is ~2°C, just above freezing point. What we call temperature is &amp;quot;Dry Bulb Temperature&amp;quot;, and it is displayed on the x-axis, in green.&lt;/li&gt;&#xA;&lt;li&gt;The relative humidity is displayed on the red curves.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Let's put a cross on the chart for the outdoor air:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aaUbM.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aaUbM.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The water content (in gram of water per gram of dry air) is displayed on the y-axis of the chart. It's approximately 0.003, or 3g/kg. It's called &amp;quot;Humidity ratio&amp;quot; on the chart. This ratio does not depend on the dry-bulb temperature.&lt;/p&gt;&#xA;&lt;p&gt;If you take outdoor air and raise its temperature from 35°F to 72°F (~2°C -&amp;gt; ~22°C), you'll land on this point:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wiDJm.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wiDJm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The relative humidity is now a bit below 20%. Which, by the way, is too dry, and your &lt;a href=&quot;https://en.wikipedia.org/wiki/Thermal_comfort#Relative_humidity&quot; rel=&quot;noreferrer&quot;&gt;nose will probably notice&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="12617" LastEditorUserId="12617" LastEditDate="2021-12-01T10:22:19.850" LastActivityDate="2021-12-01T10:22:19.850" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23235" PostTypeId="2" ParentId="23231" CreationDate="2021-12-01T11:47:05.970" Score="41" Body="&lt;p&gt;The only physics you need to know is that if the temperature is higher the air† can hold more water vapour (the gaseous phase of water). Cool molecules don't have enough energy to free themselves from intermolecular forces.&lt;/p&gt;&#xA;&lt;p&gt;The answer to your question hinges on the difference between:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;absolute humidity&lt;/strong&gt; — how much water vapour ('moisture') the air holds irrespective of temperature; and&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;relative humidity&lt;/strong&gt; — how much vapour the air holds relative to how much it &lt;em&gt;could&lt;/em&gt; hold at that temperature.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Changing the temperature of the air, e.g. by bringing it into your house, does not change how much vapour it contains but it does change its capacity, i.e. how much vapour it &lt;em&gt;could&lt;/em&gt; contain. That is, the absolute humidity stays the same, but the relative humidity changes:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;If you take cool air and warm it up, the warmer air could hold more vapour than it contains, so the relative humidity goes down.&lt;/li&gt;&#xA;&lt;li&gt;Conversely, cooling air down will push its relative humidity up. (If you cool to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Dew_point&quot; rel=&quot;noreferrer&quot;&gt;&lt;strong&gt;dew point&lt;/strong&gt;&lt;/a&gt;, you'll hit 100% relative humidity and water will condense out as dew or frost.)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I drew &lt;a href=&quot;https://docs.google.com/presentation/d/1cTxUhB4zsRiqvXFigNMe9bDN3L99aYKAGqrWR8sfxLY/edit?usp=sharing&quot; rel=&quot;noreferrer&quot;&gt;this&lt;/a&gt;, maybe it helps...&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/s4kw8.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/s4kw8.png&quot; alt=&quot;Diagram to illustrate the concepts of relative and absolute humidity&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;† Okay, this is a simplification. The conversation is about conditions in and around a house on the surface of the Earth. We don't really care about the air, per se. &lt;a href=&quot;https://en.wikipedia.org/wiki/Vapor_pressure&quot; rel=&quot;noreferrer&quot;&gt;Read about vapour pressure.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2021-12-02T20:53:14.020" LastActivityDate="2021-12-02T20:53:14.020" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23236" PostTypeId="2" ParentId="23200" CreationDate="2021-12-01T21:03:20.013" Score="2" Body="&lt;p&gt;The Iowa Environmental Mesonet is a great source for hourly data, with a bunch of options for data viewing as well as automation of downloading. &lt;a href=&quot;https://mesonet.agron.iastate.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://mesonet.agron.iastate.edu/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24980" LastActivityDate="2021-12-01T21:03:20.013" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23237" PostTypeId="1" CreationDate="2021-12-02T09:23:20.977" Score="4" ViewCount="28" Body="&lt;p&gt;I'm looking for a temperature-with-altitude measurement by a sounding rocket having gone through the tropo, strato- and mesosphere, have any such results been published after temperatures were measured when going through multiple atmosphere layers? Surely some have been.&lt;/p&gt;&#xA;&lt;p&gt;The U.S. and International Standard Atmosphere provide for &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/a/a8/International_Standard_Atmosphere.svg/1200px-International_Standard_Atmosphere.svg.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;the standard temperature with altitude profile&lt;/a&gt; of the Earth's atmosphere. This profile is from 1976 and it was corrected from the one in 1962 in which the temperature decrease in the mesosphere was portrayed differently: In the current (1976) model the temperature decreases less rapidly with altitude from about 70 km (43.5 mi) on, until the mesopause at 86 km (53 mi). In the &lt;a href=&quot;https://malagabay.files.wordpress.com/2014/07/us_standard_atmosphere_1962.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;former (1962) model&lt;/a&gt; the temperature decreased &lt;em&gt;more&lt;/em&gt; rapidly from above 60 km (37.5 mi) on, until 80 km (50 mi) altitude.&lt;/p&gt;&#xA;&lt;p&gt;I guess the difference stems from multiple results of measuring the mesospheric temperature by suborbital sounding rockets, possibly launched above different latitudes. I wonder whether such a temperature profile like those above, but measured by a sounding rocket, have been made public, containing at least the tropo-, strato- and mesosphere. Either an uncrewed one or such measurements may have been performed by crewed craft such as the X-15 or orbital craft on their way to space as well. Or by a Space Shuttle during reentry (measured OAT). Have any of such been published?&lt;/p&gt;&#xA;" OwnerUserId="24914" LastActivityDate="2021-12-02T09:23:20.977" Title="Is there any measured atmospheric temperature profile made public?" Tags="|atmosphere|temperature|measurements|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23238" PostTypeId="1" AcceptedAnswerId="23239" CreationDate="2021-12-02T13:51:00.710" Score="4" ViewCount="50" Body="&lt;p&gt;When a protolith enters in metamorphism, the minerals transform in other new stable minerals while the pressure and/or temperature increase.&lt;/p&gt;&#xA;&lt;p&gt;Is there any mineral that would not be affected by a high degree metamorphism processes and would remain the same without experiencing any change?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorUserId="2470" LastEditDate="2021-12-02T15:02:42.967" LastActivityDate="2021-12-02T15:02:42.967" Title="Is there any mineral that survives hard degree metamorphism?" Tags="|geology|mineralogy|minerals|metamorphism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23239" PostTypeId="2" ParentId="23238" CreationDate="2021-12-02T15:01:31.400" Score="2" Body="&lt;p&gt;Zircon is one mineral which &lt;a href=&quot;https://www.ga.gov.au/education/classroom-resources/minerals-energy/australian-mineral-facts/zircon&quot; rel=&quot;nofollow noreferrer&quot;&gt;survives metamorphism&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Zircons can survive processes like erosion, transport and metamorphism, so they preserve a record of past geological  processes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;From &lt;a href=&quot;https://en.wikipedia.org/wiki/Zircon&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Zircon is common in the crust of Earth. It occurs as a common accessory mineral in igneous rocks (as primary crystallization products), in metamorphic rocks and as detrital grains in sedimentary rocks.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This makes zircon very useful in determining the age of rocks.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-12-02T15:01:31.400" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23240" PostTypeId="2" ParentId="14809" CreationDate="2021-12-02T21:45:11.120" Score="3" Body="&lt;p&gt;When looking at the sky, spherical coordinates are used as a convenience. We turn our head and body in azimuth and altitude to compare the position of objects. In this regards, the sky looks like a sphere. (At least I visualize it as a sphere.) A Cartesian XY (or XYZ) grid cannot be easily used.&lt;/p&gt;&#xA;&lt;p&gt;The question then becomes: what is the path of a light beam in spherical coordinates? Realizing that light takes the shortest distance from point A to point B, another way to phrase the question is &lt;strong&gt;what is the shortest distance between two points in the sky? The answer to the re-phrase question is a great circle&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;As Bruzote's Oct 25 2021 answer was indicating, the problem is it is difficult to visualize a great circle on the sky, and the path created by a great circle is not intuitive to most people (including me). Fortunately, you can easily observe where one particular great circle exists and solve the “Moon illumination anomaly” at the same time: go out and observe the Moon! The Moon orbits the Earth in a plane, and the intersection of the orbital plane and the sky is a great circle.&lt;/p&gt;&#xA;&lt;p&gt;For example, observe the position of the Moon for several days starting a few days after New Moon. Dec 5 through the 13 2022 is a good opportunity. Make the first observation just before or at sunset and observe 4 minutes earlier on each succeeding day. (The 4 minute difference compensates for the Earth's motion around the Sun. Unless your plot of the Moon's position in the sky is precise to a fraction of a degree, you do not need to be so precise with your timing.) If you plot the position of the Moon, it will look something like the following plot: (created from &lt;a href=&quot;https://skyandtelescope.org/interactive-sky-chart/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sky and Telescope's Interactive Sky Chart&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/T9XdJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/T9XdJ.png&quot; alt=&quot;Moon's changing position Dec 5 to Dec 13 2021&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Note that:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The “straight line” of the great circle is a curve going across the sky. It does not “feel” straight. (The black line in the figure is the ecliptic, which is the great circle created by the Sun’s apparent path for 1 year. The Moon’s orbit is inclined approximately 6 degrees to the ecliptic -- close enough for reference.)&lt;/li&gt;&#xA;&lt;li&gt;The illuminated face of the Moon points toward the position of the Moon on the previous day.&lt;/li&gt;&#xA;&lt;li&gt;When connected together, the illuminated directions make a “line” (technically a great circle) that connects to the Sun. That is, the illuminated direction is in the plane of the Moon’s orbit and always faces the Sun. (The Moon's great circle crosses the Sun when there is an eclipse. At other times, the great circle may pass above or below the Sun by 6 degrees.)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;On May 16 2016, the all-sky plot looks like the following:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/li4OZ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/li4OZ.png&quot; alt=&quot;May 16 2016 sky&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;When shown in a horizon projection, the image looks like the following. The illumination on the Moon appears to be coming from the upper right because that is the shortest direction to the Sun!&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iskmJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iskmJ.png&quot; alt=&quot;May 16 2016 horizon&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;All images are approximations, just like the original photograph, due to projections from 3D onto 2D. The last image is stitched from several images which introduces more distortions.&lt;/p&gt;&#xA;" OwnerUserId="19137" LastActivityDate="2021-12-02T21:45:11.120" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="23241" PostTypeId="1" AcceptedAnswerId="23246" CreationDate="2021-12-03T12:40:26.690" Score="2" ViewCount="1396" Body="&lt;p&gt;Yesterday I saw these day and night average temperature forecasts in my local TV weather report (see image below). I kept wondering if there are 'standard day hours' and 'standard night hours' for calculating these averages in the meteorological world, or are day and night hours determined solely by the forecast provider?&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.imgur.com/1wRevi6.png&quot; alt=&quot;Text&quot; /&gt;&lt;/p&gt;&#xA;" OwnerUserId="18907" LastActivityDate="2021-12-05T13:32:08.007" Title="Standard day and night hours in weather reports" Tags="|weather-forecasting|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23242" PostTypeId="1" AcceptedAnswerId="23272" CreationDate="2021-12-03T13:38:33.023" Score="3" ViewCount="92" Body="&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What is the accuracy required in elevation to distinguish the maximal gravity anomaly of a spherical &lt;code&gt;50%&lt;/code&gt; Haematite (Iron mineral) ore with a radius of &lt;code&gt;2m&lt;/code&gt; at a depth of &lt;code&gt;10m&lt;/code&gt; within a shale section.&lt;/p&gt;&#xA;&lt;p&gt;I'm trying to solve this problem, first we know that the gravity anomaly of a sphere is that of a point mass at the sphere center equal to the product of the density and volume of the sphere, meaning that only the &lt;code&gt;ρ * V&lt;/code&gt;&#xA;product governs the anomaly and neither the size or density can be determined&#xA;individually.&lt;/p&gt;&#xA;&lt;p&gt;Directly above the sphere the maximum anomaly is:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/XcqWH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XcqWH.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;We know that in order to correct for gravity's elevation we need to use free-air formula which decreases the gravity by 0.3086 mGal for every meter above sea-level.&lt;/p&gt;&#xA;&lt;p&gt;Haematite density is: &lt;code&gt;4.9 - 5.3&lt;/code&gt; &lt;code&gt;(Mg/m^3)&lt;/code&gt;, let's assume we take the lower bound &lt;code&gt;4.9&lt;/code&gt; for this case.&lt;/p&gt;&#xA;&lt;p&gt;But we'll be taking only &lt;code&gt;50%&lt;/code&gt; of &lt;code&gt;4.9&lt;/code&gt; because only &lt;code&gt;50%&lt;/code&gt; of the ore has haematite.&lt;/p&gt;&#xA;&lt;p&gt;Also we know that &lt;code&gt;R=2m&lt;/code&gt; and &lt;code&gt;h = 10m&lt;/code&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I'm still not sure how to continue from here to find the required accuracy in elevation to distinguish the maximal gravity anomaly because I've some questions like what's the other 50% percent of the iron mineral? should we take in consideration that it's the shale section and above it we have the sandstone? and should we just sum the free air/water correction with the Bouguer correction to get the required accuracy? Any help is highly appreciated.&lt;/p&gt;&#xA;&lt;p&gt;My approach would be to calculate the free air/water correction first:&#xA;Depth is 10m which means it's &lt;code&gt;0.3086 * 10 = 3.086mGal&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;And Bouguer correction is: &lt;code&gt;δgB = 2πGρh = 2π(6.67e-11)(2.45)(-10)&lt;/code&gt; and I took &lt;code&gt;h=-10m&lt;/code&gt; because it's under the surface.&lt;/p&gt;&#xA;&lt;p&gt;Should I combine it somehow to &lt;code&gt;gz_max&lt;/code&gt; I mentioned above?&lt;/p&gt;&#xA;" OwnerUserId="24983" LastEditorUserId="2470" LastEditDate="2021-12-03T15:32:15.773" LastActivityDate="2021-12-08T14:00:48.147" Title="Elevation accuracy to distinguish maximal gravity anomaly of a sphere with 50% hematite" Tags="|geology|geophysics|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23243" PostTypeId="2" ParentId="9738" CreationDate="2021-12-03T15:17:18.233" Score="2" Body="&lt;p&gt;Oceania is a geographical region, Australia is a continent which is a part of Oceania.&lt;/p&gt;&#xA;&lt;p&gt;Oceania consists of four subregions: Australasia, Melanesia, Micronesia, and Polynesia.&lt;/p&gt;&#xA;&lt;p&gt;Australasia consists of the continent of Australia (aka Australia-New Guinea) and the submerged continent of Zealandia (aka Tasmantis). Two remote Australian external territories, Christmas Island and the Cocos (Keeling) Islands, are also considered parts of Australasia.&lt;/p&gt;&#xA;&lt;p&gt;The continent of Australia consists of three main parts: mainland Australia, the island of Tasmania, and the island of New Guinea. Mainland Australia and the island of Tasmania form the country of Australia while the island of New Guinea consists of the country of Papua New Guinea and two Indonesian provinces (Papua and West Papua). In order to distinguish between the country of Australia and the continent of Australia, some people prefer to call the continent Australia-New Guinea instead.&lt;/p&gt;&#xA;&lt;p&gt;Zealandia also consists of three main parts: New Zealand, New Caledonia, and Norfolk Island.&lt;/p&gt;&#xA;&lt;p&gt;In cultural geography, New Zealand is also considered a part of Polynesia while Papua New Guinea and New Caledonia are also considered parts of Melanesia.&lt;/p&gt;&#xA;&lt;p&gt;Therefore:&lt;/p&gt;&#xA;&lt;p&gt;Oceania (region) &amp;gt; Australasia (subregion) &amp;gt; Australia-New Guinea (continent) &amp;gt; Australia (country) &amp;gt; Mainland Australia (continental mainland) &amp;gt; Tasmania (continental island)&lt;/p&gt;&#xA;&lt;p&gt;Oceania is a unique case in world geography. It is the only geographical region which contains two continents (one of them is submerged). All the other geographical regions contain just one continent and they share the same name. For example, Asia can be either a geographical region (Asian mainland + nearby islands) or a continent (the mainland only, without any islands).&lt;/p&gt;&#xA;&lt;p&gt;Some geographers consider the underwater continental shelves and their associated continental islands to be parts of a continent. Even under this definition, there are still oceanic islands (e.g. Iceland) which are parts of a geographical region, but not parts of a continent (i.e. Iceland is a part of the European geographical region, but not a part of the European continent).&lt;/p&gt;&#xA;" OwnerUserId="24984" LastActivityDate="2021-12-03T15:17:18.233" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23244" PostTypeId="1" CreationDate="2021-12-03T15:38:39.260" Score="4" ViewCount="98" Body="&lt;p&gt;&lt;a href=&quot;https://rapidrefresh.noaa.gov/hrrr/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://rapidrefresh.noaa.gov/hrrr/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;In this dataset's GRIB format files, there are two variables representing an atomspheric pressure forecast: (output as opened with pygrib)&lt;/p&gt;&#xA;&lt;p&gt;41:MSLP (MAPS System Reduction):Pa (instant):lambert:meanSea:level 0:fcst time 0 hrs:from 202111241700&lt;/p&gt;&#xA;&lt;p&gt;62:Surface pressure:Pa (instant):lambert:surface:level 0:fcst time 0 hrs:from 202111241700&lt;/p&gt;&#xA;&lt;p&gt;I'm trying to understand how can I convert the pressure values between the two using &lt;a href=&quot;https://en.wikipedia.org/wiki/Barometric_formula&quot; rel=&quot;nofollow noreferrer&quot;&gt;barometric formula&lt;/a&gt; so that I only need to store 1 copy of the pressure grid, preferably only the MSLP pressure because they are aligned to MSL=0.&lt;/p&gt;&#xA;&lt;p&gt;According to the &lt;a href=&quot;https://journals.ametsoc.org/view/journals/mwre/118/10/1520-0493_1990_118_2099_aaslpr_2_0_co_2.xml?tab_body=pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;MAPS algorithm&lt;/a&gt; used for HRRR's sea level correction (page 2100), the sea level pressure is calculated from computing the temperature at sea level using the 700 hPa level temperature, but I tried regenerating the surface pressure values from sea level pressure and they don't match up so well (averaging &amp;gt; 2 hPa difference).&lt;/p&gt;&#xA;&lt;p&gt;I'm wondering could someone help shed light on how the MSLP grid and the SP grid in HRRR are created and whether there exists a conversion formula between the two?&lt;/p&gt;&#xA;&lt;p&gt;First question on this site. Thanks a lot in advance for your help!&lt;/p&gt;&#xA;" OwnerUserId="24985" LastEditorUserId="2470" LastEditDate="2021-12-03T16:33:41.087" LastActivityDate="2021-12-03T16:33:41.087" Title="Converting between sea level and surface pressure values in HRRR dataset" Tags="|barometric-pressure|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23245" PostTypeId="1" CreationDate="2021-12-03T15:44:23.190" Score="0" ViewCount="732" Body="&lt;p&gt;Why aren't permanently pressurized camps being built at Everest and any 23,000'+ mountain, and perhaps a pressurized enclosed platform at the very summit, to no longer have to bother about altitude sickness, HAPE and HACE, with necessary climbing equipment being in the camps already, and permanently inhabited similar to the ISS?&lt;/p&gt;&#xA;&lt;p&gt;Everest Camp II a.k.a. Advanced Base Camp is at 21,000' elevation which is still somewhat adaptable to without serious risk or effort if you're careful in acclimatization. Everest Camp III is at 23,500' which is at the very boundary of the adaptable zone (formerly, altitudes above were referred to as the Death Zone, today it's defined above 26,200'). I would suggest making Camp III and Camp IV (South Col at 26,000') pressurized and permanently inhabited by Sherpas/Rangers who exchange in periods similar to the crew on the ISS, about six months. Possibly one could establish a pressurized building at Everest's peak from where scientists may perform experiments, measurements and other stuff. On the neighbouring Lothse (27,940') one could build a pressurized observatory.&lt;/p&gt;&#xA;&lt;p&gt;The pressurizations could work similar to those on airliners. Why hasn't the above been realized as yet? Why is it so hard to realize it step-by-step?&lt;/p&gt;&#xA;" OwnerUserId="24914" LastActivityDate="2022-01-16T21:38:30.797" Title="Why doesn't one build pressurized camps at Mount Everest?" Tags="|mountains|barometric-pressure|troposphere|" AnswerCount="1" CommentCount="19" ClosedDate="2021-12-03T20:32:03.363" ContentLicense="CC BY-SA 4.0" />
  <row Id="23246" PostTypeId="2" ParentId="23241" CreationDate="2021-12-03T16:33:11.117" Score="1" Body="&lt;p&gt;I don't think a universal standard exists.&lt;/p&gt;&#xA;&lt;p&gt;The US Weather Prediction Center, which is a part of the US National Weather Service, has a standard for its reporting of nationwide daily high and low temperatures. &lt;a href=&quot;https://www.wpc.ncep.noaa.gov/discussions/hpcdiscussions.php?disc=nathilo&quot; rel=&quot;nofollow noreferrer&quot;&gt;The WPC deems&lt;/a&gt; the daily high to be the highest measured / forecast temperature that occurs between one local midnight and the next, while the daily low is the lowest measured / forecast temperature between one local noon and the next. If the low occurs prior to midnight it is reported as the low for the following day.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, &lt;a href=&quot;https://www.weather.gov/ict/f6decode&quot; rel=&quot;nofollow noreferrer&quot;&gt;other parts of the National Weather Service (in this case the Weather Service Forecast Office for Wichita, KS) deem&lt;/a&gt; the time from one local midnight to the next to suffice for both the daily high and the daily low. Many media in the US (e.g., &lt;a href=&quot;https://www.chicagotribune.com/weather/ct-wea-asktom-0203-20190202-column.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Chicago Tribune and WGN TV&lt;/a&gt; similarly use midnight to midnight for both the daily high temperature and the daily low temperature.&lt;/p&gt;&#xA;&lt;p&gt;Yet others use &lt;a href=&quot;https://www.reddit.com/r/explainlikeimfive/comments/40ja0f/comment/cyumqzi/?utm_source=share&amp;amp;utm_medium=web2x&amp;amp;context=3&quot; rel=&quot;nofollow noreferrer&quot;&gt;one sunrise to the next&lt;/a&gt; as the delineation. Weather forecasts in the media do use the term &lt;a href=&quot;https://www.baltimoresun.com/bs-mtblog-2006-12-highlow_temperature_confusion-story.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;overnight low&lt;/a&gt;, typically referring to the low temperature between sunset and sunrise.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2021-12-05T13:32:08.007" LastActivityDate="2021-12-05T13:32:08.007" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="23247" PostTypeId="1" CreationDate="2021-12-03T18:41:01.350" Score="3" ViewCount="32" Body="&lt;p&gt;Yes, there are different types of &lt;a href=&quot;https://en.wikipedia.org/wiki/Lightning#Positive_and_negative_lightning&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lightning&lt;/a&gt;. How can general public/audience detect if a cloud to ground lightning strike was of positive or negative type?&lt;/p&gt;&#xA;" OwnerUserId="22476" LastActivityDate="2021-12-03T18:41:01.350" Title="How does a layman differentiate between positive lightning and negative lightning?" Tags="|meteorology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23248" PostTypeId="2" ParentId="23245" CreationDate="2021-12-03T18:47:01.753" Score="2" Body="&lt;p&gt;The Nepali government is extremely sensitive to the notion of climbing their mountains as &amp;quot;sport&amp;quot; and understand that all elements that undermine the sporting nature of climbing, particularly on Everest, are to be restricted. For example, they have recently outlawed any on-line posting of photographs that show long lines of climbers snaking their way to the summit. They have imposed a minimum age requirement of 17 years old; after all, who'll want to climb a mountain that an 8 year old can climb.&lt;/p&gt;&#xA;&lt;p&gt;Undoubtedly, placing &amp;quot;safety cabins&amp;quot; on the mountain would eliminate much of the danger in getting to Everest's summit, and vastly reduce the allure of the adventure, and cut into the cash-cow that is climbing Everest (climbing solo, or unguided, is also largely forbidden). As a very poor country, Nepal is extremely dependent on these climber dollars. Additionally, the tourist route is already saturated with climbers, their gear, and their poop, and could in no way support even more people.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastEditorUserId="20607" LastEditDate="2022-01-16T21:38:30.797" LastActivityDate="2022-01-16T21:38:30.797" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23249" PostTypeId="1" CreationDate="2021-12-03T19:18:25.533" Score="1" ViewCount="29" Body="&lt;p&gt;Just as the production cycles of Ozone are dependent on the incident falling ultraviolet light and is fairly complex, I was wondering what the process of the production of singlet oxygen in the atmosphere results in.&lt;/p&gt;&#xA;&lt;p&gt;As Auroral light is produced, both ionized and excited state molecules, these chemical species are created in the atmosphere, yet I am unaware of what secondary products are made in this process.&lt;/p&gt;&#xA;" OwnerUserId="24416" LastEditorUserId="24416" LastEditDate="2021-12-04T05:51:46.780" LastActivityDate="2021-12-04T05:51:46.780" Title="What are the reaction mechanisms for singlet oxygen in the atmosphere?" Tags="|atmosphere|atmospheric-chemistry|upper-atmosphere|auroras|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23252" PostTypeId="2" ParentId="2644" CreationDate="2021-12-04T06:59:18.400" Score="-1" Body="&lt;p&gt;The question is not if there would be signs before a VEI8 eruption but if they would be recognized as precursors of a super eruption at all or early enough to be prepared when it happens.&lt;/p&gt;&#xA;&lt;p&gt;Unrest is such an usual thing at big explosive Calderas, and there is no Data suggesting at what level of exacerbation the Volcano becomes really dangerous (=Vei 7-8 imminent).&lt;/p&gt;&#xA;&lt;p&gt;Another point is the fact that a warning would have to be given pretty early in advance. If the unrest significantly increases just a few months, weeks or even days before the eruption it is too late, and warnings that just suggest that a super eruption might be possible within the next ten Years are probably too vague to make so many efforts for getting prepared.&lt;/p&gt;&#xA;" OwnerUserId="24994" LastEditorUserId="2470" LastEditDate="2021-12-04T11:58:13.983" LastActivityDate="2021-12-04T11:58:13.983" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23253" PostTypeId="1" CreationDate="2021-12-04T23:55:15.190" Score="3" ViewCount="35" Body="&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=wVRbeGc_6zM&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=wVRbeGc_6zM&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Notice that the cloud cover over Africa and South America is correlated in a way that seems to be highlighting some kind of large-scale easterly wave propagation near the ITCZ? I do not think that the commentary in the video addresses this.&lt;/p&gt;&#xA;&lt;p&gt;What other wave dynamics should be obvious to my eye, here? The wavenumber ~4 pattern near ±50° are Rossby waves, correct?&lt;/p&gt;&#xA;&lt;p&gt;Anyone know of a video similar to this that has commentary on the larger-scale dynamics (waves, general circulation), rather than weather?&lt;/p&gt;&#xA;" OwnerUserId="24997" LastActivityDate="2021-12-04T23:55:15.190" Title="Why does cloud cover seem to &quot;ride&quot; a wave that propagates westward near the equator in this video?" Tags="|meteorology|climatology|atmospheric-circulation|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23254" PostTypeId="1" AcceptedAnswerId="23282" CreationDate="2021-12-05T00:30:11.960" Score="5" ViewCount="112" Body="&lt;p&gt;Green house gases typically have higher lifetimes than aerosols and their precursors (e.g. SO&lt;sub&gt;2&lt;/sub&gt;) so, as I understand it, GHGs usually spread more or less evenly across continents, no matter where they are emitted from, whereas aerosols' concentrations are much more heterogeneous and higher near the sources. As a result, all things being equal, big emitters' GHGs affect other countries more in part because big emitters have &amp;quot;aerosol shields&amp;quot;, so to speak, since aerosols and their precursors are often emitted alongside GHGs and have a cooling effect. Am I right?&lt;/p&gt;&#xA;" OwnerUserId="22632" LastEditorUserId="24481" LastEditDate="2021-12-12T15:44:12.403" LastActivityDate="2021-12-12T15:44:12.403" Title="Do &quot;aerosol shields&quot; protect big emitters from the impact of their own GHGs?" Tags="|climate-change|atmosphere|climatology|aerosol|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23256" PostTypeId="1" AcceptedAnswerId="23386" CreationDate="2021-12-05T18:19:43.043" Score="3" ViewCount="238" Body="&lt;p&gt;What would happen if you threw a geode into the ocean. Would it sink down to a certain altitude based on how hollow the geode is or would it float on top or sink to the bottom?&lt;/p&gt;&#xA;&lt;p&gt;And could geodes form in the ocean and then break loose and be released into the ocean? Do geodes in the ocean exist?&lt;/p&gt;&#xA;" OwnerUserId="24999" LastEditorDisplayName="user20559" LastEditDate="2022-01-13T13:36:20.440" LastActivityDate="2022-01-13T13:36:20.440" Title="Geodes that float in the ocean?" Tags="|geology|geode|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23257" PostTypeId="1" CreationDate="2021-12-06T01:54:33.183" Score="3" ViewCount="54" Body="&lt;p&gt;Out of all the layers of the Earth's atmosphere the Mesosphere is the hardest to collect data and experiment on, due to it's density being too much for satellites and too little for aircraft or balloons.&#xA;Yet due to it's rarified air and it being a transient layer, I cannot think of how the lack of knowledge of this layer affects our understanding and predictive qualities of the Earth's system. That being the case, how would gathering more qualitative and quantitative data from the Mesosphere help?&lt;/p&gt;&#xA;" OwnerUserId="24416" LastEditorUserId="24416" LastEditDate="2021-12-06T23:30:11.033" LastActivityDate="2021-12-06T23:30:11.033" Title="How does the lack of data about the Mesosphere affect our predictive knowledge of the atmosphere?" Tags="|meteorology|atmosphere|data-analysis|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23259" PostTypeId="1" CreationDate="2021-12-06T05:13:37.793" Score="1" ViewCount="45" Body="&lt;p&gt;I came across these two terms and not sure if they could more or less be considered the same thing.&lt;/p&gt;&#xA;&lt;p&gt;wikipedia defines it as:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Waste heat is heat that is produced by a machine, or other process&#xA;that uses energy, as a byproduct of doing work. All such processes&#xA;give off some waste heat as a fundamental result of the laws of&#xA;thermodynamics.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In that wikipedia there is a section talking about disposal, not sure if that is the same though. It says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Low temperature heat contains very little capacity to do work&#xA;(Exergy), so the heat is qualified as waste heat and rejected to the&#xA;environment. Economically most convenient is the rejection of such&#xA;heat to water from a sea, lake or river. If sufficient cooling water&#xA;is not available, the plant can be equipped with a cooling tower or&#xA;air cooler to reject the waste heat into the atmosphere. In some cases&#xA;it is possible to use waste heat, for instance in district heating&#xA;systems.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Wondering if anyone on here has insights into it.&lt;/p&gt;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="25003" LastActivityDate="2021-12-06T11:39:31.427" Title="What is the difference between Waste Disposal Services and Waste heat?" Tags="|energy|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23260" PostTypeId="1" CreationDate="2021-12-06T07:53:41.457" Score="4" ViewCount="91" Body="&lt;p&gt;When solving equations involving the Coriolis parameter &lt;span class=&quot;math-container&quot;&gt;$f = 2\Omega\sin{\varphi}$&lt;/span&gt;, I often see the &lt;span class=&quot;math-container&quot;&gt;$f$&lt;/span&gt;-plane (constant) or the &lt;span class=&quot;math-container&quot;&gt;$\beta$&lt;/span&gt;-plane (Taylor expansion) approximations.&lt;/p&gt;&#xA;&lt;p&gt;If I'm solving equations on a larger scale in a cartesian coordinate space, would re-projecting the cartesian coordinates onto the sphereoid and re-calculating the Coriolis parameter with the given latitude (&lt;span class=&quot;math-container&quot;&gt;$\varphi$&lt;/span&gt;) be any less accurate than the &lt;span class=&quot;math-container&quot;&gt;$\beta$&lt;/span&gt;-plane approximation?&lt;/p&gt;&#xA;&lt;p&gt;Is the purpose of these approximations to reduce the computational complexity of the model, or somehow to maintain a higher degree of numerical accuracy as opposed to the alternative approach described above?&lt;/p&gt;&#xA;" OwnerUserId="25006" LastEditorUserId="25006" LastEditDate="2021-12-06T12:56:32.090" LastActivityDate="2022-12-27T21:11:54.950" Title="Coriolis parameter approximations" Tags="|geophysics|oceanography|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23261" PostTypeId="2" ParentId="23259" CreationDate="2021-12-06T11:39:31.427" Score="1" Body="&lt;p&gt;The title of the question and the text associated with it do not match.&lt;/p&gt;&#xA;&lt;p&gt;The title mentions waste disposal services and waste heat, but the text only discusses waste heat.&lt;/p&gt;&#xA;&lt;p&gt;Waste disposal services are any services that dispose of &lt;em&gt;any&lt;/em&gt; waste. A sewage treatment plant is a waste disposal service, as is a land fill facility for any form of rubbish as is a waste incineration plant.&lt;/p&gt;&#xA;&lt;p&gt;As for the block quotations concerning waste heat in the text, the first quotation simply gives a definition/example of waste. Some examples of this would be the heat generated when metal is being shaped on a lathe. The friction between the cutting tool and the metal item generates heat. To prevent thermal damage to both the item being cut and the cutting tool both needsto be cooled so they are constantly flushed by a cooling liquid during the cutting proces. This heats the liquid which is then transported elsewhere, such as a heat exchanger to be cooled. The heat from the exchanger then releases the heat either to the atmosphere or undergoes another cooling process.&lt;/p&gt;&#xA;&lt;p&gt;Heat produced by an internal combustion engine is another example. The engine contains voids that are filled with water or water and coolant and the waste heat is ejected to the atmosphere via the radiator.&lt;/p&gt;&#xA;&lt;p&gt;The second block quotation gives examples of how waste heat can be disposed: into bodies of water such as rivers, lake or the ocean or the atmosphere cooling towers.&lt;/p&gt;&#xA;&lt;p&gt;In thermal power stations that heat water to produce steam that turns turbines to generate electricity, such a coal, gas or nuclear power stations, once the steam leaves the turbines it needs to be cooled for form water so it can be reused. The way it loses heat is via cooling towers. In colder climates, such as Russia, such heat can be used to provide communal heating for domestic purposes.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-12-06T11:39:31.427" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23263" PostTypeId="1" CreationDate="2021-12-06T15:27:11.670" Score="4" ViewCount="69" Body="&lt;p&gt;Since our planet's magnetic poles are not usually, precisely, lined up with the geographic poles of Earth's axis, and since they move around a lot, can paleomagneticists (is that a word?) determine the dates of ancient rock formation more precisely using this extra information?&lt;/p&gt;&#xA;&lt;p&gt;Or vice versa? (I.e., does knowing, somehow, the precise date of formation of a rock(s), then measuring its exact direction of magnetism, not just polarity, tell you where the magnetic poles were at that time?)&lt;/p&gt;&#xA;" OwnerUserId="20985" LastActivityDate="2021-12-14T13:07:12.033" Title="Can paleomagnetic techniques determine the exact direction of Earth's magnetic poles in the past, not just their polarity?" Tags="|geology|geomagnetism|paleomagnetism|archaeology|rock-magnetism|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23264" PostTypeId="1" CreationDate="2021-12-06T22:59:26.087" Score="9" ViewCount="1571" Body="&lt;p&gt;I imagine it is difficult for the ocean to freeze solid due to the low freezing point of salt water and the insulating effect of the formation of sea ice over the cool but still liquid ocean water.&lt;/p&gt;&#xA;&lt;p&gt;Certainly for the ocean to freeze entirely, I think first the entire ocean would have to cool to near freezing even in the tropics. I also think that even supposing the Earth's atmosphere were at a uniform temperature below freezing (say -20 °C worldwide), the ocean may still not freeze since it receives approx. 0.1 W/m² in heat flux from the Earth's interior.&lt;/p&gt;&#xA;&lt;p&gt;Assuming a simple model with an atmosphere of uniform global temperature, and assuming that the layer of sea ice accommodates all of the temperature difference between the surface/air and the still unfrozen water which is I assumed to be isothermal at near freezing, with simplifying assumptions about the properties of ice as an insulator and heat flux from the mantle,&lt;/p&gt;&#xA;&lt;p&gt;I related the heat flux from the cold surface/air layer to the heat flux from the mantle, assuming the isothermal ocean had reached a state of constant temperature&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$h(T - t_0 ) = Q_g$&lt;/span&gt;, where&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$h$&lt;/span&gt; is a thermal property of the ice (&lt;span class=&quot;math-container&quot;&gt;$k/d$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$d$&lt;/span&gt; is the&#xA;ice thickness)&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; is the constant water temperature of near 275 K&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$t_0$&lt;/span&gt; is the external temperature&lt;/li&gt;&#xA;&lt;li&gt;And &lt;span class=&quot;math-container&quot;&gt;$Q_g$&lt;/span&gt; is the heat flux from the mantle&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;From this, I calculated that in this very simple model the required temperature of the air to create a layer of sea ice of thickness d can be found with this expression:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$t_0 = T - (Q_gd)/k$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Using a thickness of 4000 m, which would be a layer of sea ice that fills most of the ocean, I guess that the surface temperature of the Earth would have to be around 120 K for the oceans to freeze solid.&lt;/p&gt;&#xA;&lt;p&gt;I don't think that I am right- obviously much is neglected in this model and some of my assumptions may not be warranted. Clearly, the Earth would have to be much colder than any time in its history for the oceans to freeze at great depth, but my question is would it have to be even colder than I have guessed, or could the oceans freeze completely or almost completely at warmer global temperatures than 120 K?&lt;/p&gt;&#xA;" OwnerDisplayName="user13823" LastEditorUserId="2470" LastEditDate="2021-12-07T16:51:07.983" LastActivityDate="2023-10-21T02:03:45.423" Title="How cold would the Earth have to be for the oceans to freeze entirely?" Tags="|climate|oceanography|ice|sea-ice|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23265" PostTypeId="1" AcceptedAnswerId="23266" CreationDate="2021-12-07T11:55:54.300" Score="7" ViewCount="1093" Body="&lt;p&gt;Excerpt from WP page &lt;a href=&quot;https://en.wikipedia.org/wiki/Snow_line&quot; rel=&quot;noreferrer&quot;&gt;Snow line&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;At or near the equator, it is typically situated at approximately 4,500 metres (14,764 ft) above sea level. As one moves towards the Tropic of Cancer and Tropic of Capricorn, the parameter at first increases: in the Himalayas the permanent snow line can be as high as 5,700 metres (18,701 feet)...&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;Why does the snow line increase? Logically, shouldn't it decrease the farther you go from the equator? Or is the 14,764 ft figure meant to be the &lt;em&gt;average&lt;/em&gt; snow line rather than the permanent one and the &amp;quot;at first increases&amp;quot; quote is a misinterpretation?&lt;/p&gt;&#xA;" OwnerUserId="24914" LastActivityDate="2021-12-07T13:45:43.063" Title="Why is the snow line higher in the Himalayas than on the equator?" Tags="|meteorology|temperature|snow|troposphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23266" PostTypeId="2" ParentId="23265" CreationDate="2021-12-07T13:45:43.063" Score="8" Body="&lt;p&gt;The permanent snow line is controlled by summer insolation, and during the summer the insolation is higher at 30°N than at the equator. See this figure from &lt;a href=&quot;http://www.physicalgeography.net/fundamentals/6i.html&quot; rel=&quot;noreferrer&quot;&gt;Fundamentals of Physical Geography&lt;/a&gt; (Pidwirny, 2006):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/n1oAv.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/n1oAv.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;You can see that the 30°N latitude (roughly that of the Himalayas) gets higher insolation than the equator from mid-April to end of August, which is enough time for the snow to melt in the summer at higher altitudes. Higher latitudes also get more insolation than the equator in the summer, but for a much shorter amount of time, which is why the snow line trend decreases after the tropic.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2021-12-07T13:45:43.063" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23268" PostTypeId="2" ParentId="18918" CreationDate="2021-12-07T20:16:07.147" Score="2" Body="&lt;p&gt;&lt;strong&gt;No, this is not practicable.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Imagine making another Lake Superior, the 3rd most voluminous lake on Earth, which &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Superior&quot; rel=&quot;nofollow noreferrer&quot;&gt;according to Wikipedia&lt;/a&gt; holds 10% of the world's fresh surface water (excluding the ice in Antarctica). It has a volume of 12,100 km&lt;sup&gt;3&lt;/sup&gt;, and would cover about one-fifth of California (at the same depth of about 150 m).&lt;/p&gt;&#xA;&lt;p&gt;The ocean has an area of 361 million km&lt;sup&gt;2&lt;/sup&gt;, so removing another Lake Superior's worth of water would reduce its depth &lt;span class=&quot;math-container&quot;&gt;$d$&lt;/span&gt; by:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\Delta d = \frac{12.1\times 10^3}{361 \times 10^6} = 33.5\times 10^{-6}\ \mathrm{km, or}\ 33.5\ \mathrm{mm} $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;... a bit over one inch. According to &lt;a href=&quot;https://sealevelrise.org/states/california/&quot; rel=&quot;nofollow noreferrer&quot;&gt;sealevelrise.org&lt;/a&gt;, this is about 10 years' worth of rise.&lt;/p&gt;&#xA;&lt;p&gt;If you had 639 5400-horsepower Pentair Fairbanks Nijhuis pumps (the &lt;a href=&quot;https://actionelectricmotorandpump.com/2019/01/fun-fact-whats-the-largest-pump-in-the-world/&quot; rel=&quot;nofollow noreferrer&quot;&gt;most powerful pump&lt;/a&gt; in the world, built for keeping the Netherlands dry), you could pump at 38 million litres per second and keep up with sea-level change (not accounting for evaporation or rainfall). At 4000 kW per pump, I think this would require the combined output from the six or seven largest solar farms in California, or a bit more than the output of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Diablo_Canyon_Power_Plant&quot; rel=&quot;nofollow noreferrer&quot;&gt;Diablo Canyon nuclear power plant&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Unfortunately, there are a lot of other factors controlling local sea-level; &lt;a href=&quot;https://earthscience.stackexchange.com/a/5455/70&quot;&gt;see this other answer for example&lt;/a&gt;. Not to mention the issue of figuring out where this saline lake will go...&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2022-08-18T17:39:52.597" LastActivityDate="2022-08-18T17:39:52.597" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23269" PostTypeId="2" ParentId="1076" CreationDate="2021-12-07T23:38:12.200" Score="1" Body="&lt;p&gt;This question has too many variables to be answered mathematically.&lt;/p&gt;&#xA;&lt;p&gt;In a practical sense, avoid snow on your near-vertical surfaces by gently heating them.&lt;/p&gt;&#xA;&lt;p&gt;Example: Modern LED traffic lights can be obscured by snow on the lenses because they run at lower power than the old-school incandescent lights, and have much lower losses to heat.  Therefore new LEDs are colder and less-able to soften and shed driven snow than a slightly warm filament-based lamp.&lt;/p&gt;&#xA;" OwnerUserId="19210" LastActivityDate="2021-12-07T23:38:12.200" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23270" PostTypeId="1" CreationDate="2021-12-08T02:18:01.097" Score="5" ViewCount="48" Body="&lt;p&gt;I am having a hard time finding this anywhere -- if no one can answer, I would appreciate a reference.&#xA;I was doing introductory homework in earth science, and we had to determine the kind of plate boundary via earthquake data.&lt;/p&gt;&#xA;&lt;p&gt;We were given earthquake depths and locations at certain distances away from an oceanic trench. There were several volcanoes given as well (at depth of zero, a certain distance away from the trench).&lt;/p&gt;&#xA;&lt;p&gt;Given the diversity of the depths of these earthquakes (ranging from 100km - 600km), it was easy to tell that it was a convergent boundary. The trench gives away that at least one plate is oceanic.&lt;/p&gt;&#xA;&lt;p&gt;But I can't figure out how to tell from this data whether or not the collision is Ocean-Continent, or Ocean to Ocean.&lt;/p&gt;&#xA;&lt;p&gt;Is there a way to tell just from the data given?&lt;/p&gt;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="25016" LastActivityDate="2021-12-08T02:18:01.097" Title="Difference between Ocean-Ocean subduction and Continental-Ocean from earthquake data" Tags="|plate-tectonics|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23272" PostTypeId="2" ParentId="23242" CreationDate="2021-12-08T11:50:42.487" Score="1" Body="&lt;p&gt;&lt;strong&gt;Solution:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;If &lt;code&gt;gz_max&lt;/code&gt; is bigger than the air correction then we're done. because we can measure the signal. and we're done. &lt;code&gt;So gz_max &amp;gt; e_h&lt;/code&gt; is the requirement.&lt;/p&gt;&#xA;&lt;p&gt;(If the error is bigger than the signal anomaly then we can't measure the signal.)&lt;/p&gt;&#xA;" OwnerUserId="24983" LastEditorUserId="24983" LastEditDate="2021-12-08T14:00:48.147" LastActivityDate="2021-12-08T14:00:48.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23273" PostTypeId="2" ParentId="1076" CreationDate="2021-12-08T12:25:27.500" Score="2" Body="&lt;p&gt;The angle of 32° for the lower bound angle given in the answer by @Pytrik reminded me of the &amp;quot;typical&amp;quot; &lt;a href=&quot;https://en.wikipedia.org/wiki/Angle_of_repose&quot; rel=&quot;nofollow noreferrer&quot;&gt;angle of repose&lt;/a&gt; for most materials, particularly soil and rock.&lt;/p&gt;&#xA;&lt;p&gt;The angle of repose is defined as,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The steepest angle of descent or dip relative to the horizontal plane to which a material can be piled without slumping.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gPzRz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gPzRz.png&quot; alt=&quot;angle_of_repose&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;a href=&quot;https://www.cambridge.org/core/journals/journal-of-glaciology/article/angle-of-repose-experiments-with-snow-role-of-grain-shape-and-cohesion/B45F663C64F56568AFD2B9E2BFA113A6&quot; rel=&quot;nofollow noreferrer&quot;&gt;Angle of repose experiments with snow: role of grain shape and cohesion&lt;/a&gt;&lt;/em&gt; was published Cambridge University Press on 27 May 2020.&lt;/p&gt;&#xA;&lt;p&gt;The shape of the snow particles, their cohesion and temperature and whether or not the snow had become &lt;a href=&quot;https://en.wikipedia.org/wiki/Sintering&quot; rel=&quot;nofollow noreferrer&quot;&gt;sintered&lt;/a&gt; all factor into angle of repose for snow for a given set of conditions.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In the experiments, we observed a significant influence of particle shape and cohesion, with both factors increasing the angle of repose. The influence of shape was revealed by examining different snow types and spherical particles, and the cohesion, assumed to be caused by sintering, was examined by varying the temperature. Complex-shaped snow particles clearly formed larger angles than the spherical particles. More specifically, the smaller the shape parameter, the larger was the angle of repose. The influence of cohesion was negligible at temperatures below −22°C, but increased as the temperature increased to −2°C.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It was observed the angle of repose increased the more shape of a snow particle deviated from a sphere. Basically, the more angular the snow particle the higher its angle of repose.&lt;/p&gt;&#xA;&lt;p&gt;When it comes to the effects of sintering, the angle of repose ...&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;increased at higher temperatures, between −15 and −5, and even more between −5 and −2°C.&lt;/p&gt;&#xA;&lt;p&gt;Often, sintering is discussed in close connection to friction, which constitutes another temperature-dependent process for ice. However, its role in the angle of repose is not clear. While it is the key parameter in Mohr–Coulomb theory, which is often used for a theoretical analysis of the angle of repose (MCGlinchey, Reference McGlinchey2005), other studies conclude that friction plays a sub-dominant role behind particle shape and cohesion, and can therefore be neglected (Nowak and others, Reference Nowak, Samadani and Kudrolli2005).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The picture below is taken from the article. Particle with a smoother shape have a lower angle of repose; the bottom set of blue lines with an angle of repose around 20°. The more angular the shape of the particles, the higher the angle of repose; the yellow and green lines with an angle of repose around 30° to 40°, depending on temperature. In both of these situations, the angle of repose increase with temperature.&lt;/p&gt;&#xA;&lt;p&gt;The fact that snow can deposit on a vertical surface would indicate the snow particles would be angular and would have a degree of sintering.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GYS3o.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GYS3o.png&quot; alt=&quot;Snow_repose_angle&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-12-08T12:25:27.500" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23274" PostTypeId="1" CreationDate="2021-12-08T12:43:39.883" Score="3" ViewCount="38" Body="&lt;p&gt;While working on investigation of seismic anisotropy I came to know that core refracted phases like SKS or SKKS polarise vertically when P to S conversion happens in the Core-Mantle boundary. Why is the S wave in this case always polarised vertically ? Can we get horizontally polarised S wave in this scenario ?&lt;/p&gt;&#xA;" OwnerUserId="25010" LastActivityDate="2021-12-08T12:43:39.883" Title="Why core refracted phases like SKS polarise vertically when P to S conversion happens in the Core-Mantle boundary?" Tags="|seismology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23275" PostTypeId="2" ParentId="7086" CreationDate="2021-12-08T16:44:31.967" Score="3" Body="&lt;p&gt;A brief explanation is that Earth is not a perfect sphere moving in a perfect circle. Our planet is tilted, and its tilt does not align with its orbit’s apses (its perihelion or aphelion, its nearest or farthest positions from its sun).&lt;/p&gt;&#xA;&lt;p&gt;A result of these imperfections can be seen in the analemma (something commonly drawn on well-made globes). &lt;a href=&quot;https://www.lexico.com/en/definition/analemma&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oxford&lt;/a&gt; Dictionary describes the analemma thus:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;the asymmetrical figure-eight curve that can be traced in the sky at a given place showing the position of the sun at the same standard time (usually twelve o'clock) on successive days of a year.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The analemma isn’t just drawn on globes, but it can be observed in the sky. The below diagram visualizes the effect. It comes from analemma.com’s &lt;a href=&quot;https://www.analemma.com/phenomena.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Phenomena&lt;/a&gt; page, which has several more diagrams on separate pages to illustrate the effect.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dSk33.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dSk33.jpg&quot; alt=&quot;Diagram of analemma at sunrise and sunset.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="25021" LastActivityDate="2021-12-08T16:44:31.967" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23277" PostTypeId="1" CreationDate="2021-12-09T06:47:21.473" Score="4" ViewCount="77" Body="&lt;p&gt;I am calculating the sensible heat (H) using MOST and have run into a few problems.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aXrNs.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aXrNs.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;First off, I calculated an initial H (from Rn-G-LvET) to start the iteration.&lt;/li&gt;&#xA;&lt;li&gt;Using Eqn 2-5, I calculated u*(1), L(1), H (1) using Eqn 1 (L(1) &amp;gt; 0).&lt;/li&gt;&#xA;&lt;li&gt;Repeat point 2 until L converges.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;My problem is that my L never converges even though I have run &amp;gt;10,000 iterations. Another issue is that I get ridiculous H values (&amp;gt; &amp;amp; &amp;lt; 1000). Am I approaching this correctly?&lt;/p&gt;&#xA;" OwnerUserId="25018" LastEditorUserId="25018" LastEditDate="2021-12-09T09:34:47.683" LastActivityDate="2021-12-09T09:34:47.683" Title="Calculating Sensible Heat using Monin-Obukhov Similarity Theory (Stable Stratification)" Tags="|energy-balance|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23279" PostTypeId="2" ParentId="19664" CreationDate="2021-12-10T11:45:10.247" Score="3" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;Does this mean that the shape of Earth itself is unique...?&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Yes, the Earth's shape is what is called a &lt;a href=&quot;https://en.wikipedia.org/wiki/Geoid&quot; rel=&quot;nofollow noreferrer&quot;&gt;geoid&lt;/a&gt;. This is an exaggerated portrayal of it: &lt;a href=&quot;https://i.stack.imgur.com/3ZSTK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3ZSTK.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But the best approximation is an oblate ellipsoid of course.&lt;/p&gt;&#xA;" OwnerUserId="24914" LastEditorUserId="2470" LastEditDate="2021-12-10T15:50:56.973" LastActivityDate="2021-12-10T15:50:56.973" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23280" PostTypeId="2" ParentId="22385" CreationDate="2021-12-10T12:22:07.557" Score="6" Body="&lt;p&gt;To start with, quite a bit of the odds is actually built into the product.  They don't include the scale for the values right on your interactive link, but they do show it as percentage odds on &lt;a href=&quot;https://www.cpc.ncep.noaa.gov/products/predictions/814day/&quot; rel=&quot;nofollow noreferrer&quot;&gt;the static page&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZB65Nm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZB65Nm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But the interactive page actually gives a more precise breakdown of the forecasted potentials for a location of interest.  From your link, click on the city of interest on the map or put it in the &amp;quot;Find address or place&amp;quot; box, and you get:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/a9FnW.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/a9FnW.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The green circled section at left is their display of odds for their three categorical options.  Breaking down those options... isn't as well explained as it could be.  They don't give value ranges for what each category means, and it took a little wandering to find &lt;a href=&quot;https://www.cpc.ncep.noaa.gov/products/predictions/erf_info.php?outlook=814&amp;amp;var=t&quot; rel=&quot;nofollow noreferrer&quot;&gt;their mathematical description&lt;/a&gt; of what constitutes above/near/below normal, using the standard distribution calculator from &lt;a href=&quot;https://onlinestatbook.com/2/calculators/normal_dist.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; (which matches this CPC &lt;a href=&quot;https://www.cpc.ncep.noaa.gov/products/NMME/NMME_PROB_descr.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;page&lt;/a&gt;) and combining with this &lt;a href=&quot;https://mesonet.agron.iastate.edu/plotting/auto/?_wait=no&amp;amp;q=25&amp;amp;state=WI&amp;amp;month=12&amp;amp;day=20&amp;amp;_r=t&amp;amp;dpi=100&amp;amp;_fmt=png&quot; rel=&quot;nofollow noreferrer&quot;&gt;climatology plotter&lt;/a&gt;, it looks like the forecast roughly is saying the chances of daily average temperature ranges are:&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th style=&quot;text-align: left;&quot;&gt;temperature range for daily average&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: center;&quot;&gt;odds&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: left;&quot;&gt;&amp;gt;25 °F&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;45%&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: left;&quot;&gt;14-25 °F&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;33%&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: left;&quot;&gt;&amp;lt;14 °F&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;22%&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;&#xA;&lt;p&gt;(I'm just looking at average temperature for each day, which is the average of the high and low temperature each day... but the same idea applies to the highs and lows... being within about 5 degrees of average is considered near normal this time of year based on their method)&lt;/p&gt;&#xA;&lt;p&gt;So right up front, their forecast isn't saying anything too emphatic or perhaps too useful to many.  It shows that the forecast leans warm, but not even half of the outcomes will wind up quite warm (more than 5 degrees above normal).  Put another another way, it's like saying there's a 45% chance of heavy rain, a 33% chance of fog and drizzle, and a 22% chance of being sunny.  Will your event be rained out?  Hard to have too much confidence!  But yet it does at least show the lean (for my example, it does seem weather is at least be a factor... for this, same idea: there's only a bit of lean towards warm, but the odds of it being abnormally cold look a fair bit lower)&lt;/p&gt;&#xA;&lt;p&gt;This doesn't directly allow us to calculate the odds of the results coming in anywhere below average as you've asked for... but it would seem a fair estimate is cutting the near normal group up with the same scaling as the below-to-above category ratio, &lt;strong&gt;which would give this site a 33% chance of winding up below the 50th percentile.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;hr&gt;&#xA;Now that is only the forecast, based generally on model ensembles and such.  It still doesn't include any measure of how *reliable* the forecasts are.  The Climate Prediction Center site itself actually has some info towards that aspect of your question... unfortunately the page you happened to come from them had bad verification links.  But the main [CPC page][7] (as of now at least) has a [proper link to verification][7], on the left sidebar under Outlooks(Forecast) &gt; Verification.&#xA;&lt;p&gt;Then we need to trudge through the complexity of how &lt;a href=&quot;https://en.wikipedia.org/wiki/Forecast_skill&quot; rel=&quot;nofollow noreferrer&quot;&gt;forecasts are scored&lt;/a&gt;, particularly areal ones.  The CPC verification focuses around a Heidke score.&lt;/p&gt;&#xA;&lt;p&gt;If I understand everything, the basics are: 0 is no skill, 100 is perfect.  Or 0 bad, 100 great.  Here are those Heidke Skill Scores for the 8-14 day temperature forecast over the past year as of yesterday:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NfYkU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NfYkU.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(These are just focusing on the three color category types on the map, the orange\red region, the gray region, and the blue region...)&lt;/p&gt;&#xA;&lt;p&gt;So I believe that says a mean skill score around 20 suggests a forecast only ends up having its skill about 1 out of 5 times.  So basically that knocks 80% off the indicated category differences the models suggested... such that it's really more like a 45% chance (&lt;span class=&quot;math-container&quot;&gt;$.50-\frac{.33}{5}$&lt;/span&gt;) that it comes in under the mean, a 55% chance it comes in over the mean.&lt;/p&gt;&#xA;&lt;p&gt;So for all these graphics are shown in like the media, they really aren't saying much.  Furthermore, would think that the lighter orange areas tend to have less categorical skill than the deeper red areas because errors are often geographic (due to systems being slower/faster/deeper/shallower than forecast), meaning the border areas are more likely to swing into the opposite category... so the skill is probably even less yet.  It's literally a forecast of a few percent improvement on even... something like a 53% chance a coin comes up heads and 47% chance it comes up tails for yours, pretty unhelpful knowledge for any specific flip.&lt;/p&gt;&#xA;&lt;p&gt;Only if the tiny return gained from using such products is scaled to big-value repeatable things is their significant benefit... namely things like agriculture... where the small percentage gained is multiplied by a lot of money/food, which over the long-run will equate to tangible gains of expected value return.&lt;/p&gt;&#xA;&lt;p&gt;How have these forecasts done in the long range?  The main verification page only shows skill score for the 8-14 day over the past year.  I believe &lt;a href=&quot;https://vwt.ncep.noaa.gov&quot; rel=&quot;nofollow noreferrer&quot;&gt;this page&lt;/a&gt; may have longer-term plots, as I'm pretty sure I've seen them in the past... but the page is down right now.&lt;/p&gt;&#xA;&lt;p&gt;The Heilke graph above is expectedly noisy but roughly steady; there haven't been drastic 8-14 day forecast tool changes in the past year.  All I can find right now is graphs of monthly and seasonal forecasts over the longer-run.  Here's the &lt;em&gt;one-month&lt;/em&gt; forecast skill variation:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/e1HLN.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/e1HLN.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Not a lot of change, nor a lot of skill.&lt;/p&gt;&#xA;&lt;p&gt;Likewise &lt;a href=&quot;https://journals.ametsoc.org/view/journals/wefo/27/4/waf-d-11-00143_1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;this journal article&lt;/a&gt; and sites like &lt;a href=&quot;https://ggweather.com/cpc/verify/cpc_winter.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one&lt;/a&gt; shows there hasn't been much improvement in seasonal scores in general.&lt;/p&gt;&#xA;&lt;hr&gt;&#xA;&lt;p&gt;From everything I've seen, well-made longer-range forecasts, whether for two weeks or seasonal temperatures or hurricanes or whatever, they all tend to have &amp;quot;skill&amp;quot;... as in they are the slightest bit right more than they're wrong.  But in terms of making plans around, they typically don't say too much a person can use at all.  And to be &amp;quot;skillful&amp;quot; they also have to have very broad range categories (a forecast of 16 named tropical cyclones is almost certain to be wrong, but a range of 13-20 named tropical cyclones &lt;a href=&quot;https://en.wikipedia.org/wiki/2021_Atlantic_hurricane_season#Seasonal_forecasts&quot; rel=&quot;nofollow noreferrer&quot;&gt;like NOAA gave this year&lt;/a&gt; is more likely to be right... even if it does cover everything from a slightly below average season to a near record season [it was still wrong this year!]... likewise an Accuweather forecast of a high of 27 °F three weeks from Thursday is absolutely silly, but a 37% chance the temperature that week will be in the upper third tertile is in theory a valid &amp;quot;gain&amp;quot;... a very very tiny-use one)&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;For the 8-14 day forecast, unless you're in one of the very high colors on the 8-14 day outlook scale (the very dark blues or deep reds), I wouldn't put much thought towards them at all.&lt;/strong&gt;  They may be a hint that a front (or warmup) may happen at some point during/near that period, but it's hard to narrow down that far into the future as of now.  I am convinced such long-range forecast are focused upon far too much versus their typically minuscule usefulness.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2023-04-05T09:39:40.977" LastActivityDate="2023-04-05T09:39:40.977" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23282" PostTypeId="2" ParentId="23254" CreationDate="2021-12-10T22:31:37.253" Score="4" Body="&lt;p&gt;Your general line of thinking is correct. However, here are a few things that make the whole concept somewhat more complicated:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;It is widely accepted that the general tendency of &amp;quot;global dimming&amp;quot;&#xA;(due to increased aerosol emissions) has been reversed above most&#xA;regions since the 1980s-1990s, i.e. there has been &amp;quot;global&#xA;brightening&amp;quot; [see &lt;a href=&quot;https://doi.org/10.1175/BAMS-D-11-00074.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wild (2012)&lt;/a&gt; or &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2017/09/WG1AR5_Chapter02_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;IPCC (2013)&lt;/a&gt;]. If we accept that dimming mainly has a cooling effect,&#xA;then despite big emitters having this &amp;quot;shield&amp;quot; as you nicely put it,&#xA;the trend during recent decades is a weakening of this &amp;quot;shield&amp;quot;,&#xA;i.e. a warming effect. That is: there is less warming compared to a&#xA;hypothetical absence of heavy load of aerosols above these regions,&#xA;but there is more warming compared to their own past conditions (and&#xA;as is known, the most worrying aspect of global warming is not the&#xA;high absolute temperatures, but their wildly unnatural and quickly&#xA;increasing trend).&lt;/li&gt;&#xA;&lt;li&gt;The effect of dimming and brightening, due to&#xA;increasing and decreasing aerosols in the atmosphere respectively,&#xA;is not always cooling and warming respectively. The type of aerosols&#xA;responsible for these trends plays an important role. Reflecting&#xA;aerosols in general have a cooling effect, because they allow less&#xA;solar radiation to enter the Earth's energy balance, but absorbing&#xA;aerosols (e.g. black carbon) do not necessarily have such a cooling effect: the solar&#xA;radiation blocked by them does not reach the planetary surface, but&#xA;is nevertheless absorbed by the atmosphere, and thus contributes to&#xA;the energy balance (simply put, the energy that you do not get on&#xA;the ground, you still get in the atmosphere and thus you have no cooling&#xA;effect). [See &lt;a href=&quot;https://earthobservatory.nasa.gov/features/Aerosols/page3.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA (2010)&lt;/a&gt;]&lt;/li&gt;&#xA;&lt;li&gt;While generally, as you said, aerosols don't spread&#xA;evenly over the planet, it has been hypothesized that there is a&#xA;saturation aspect in their dimming effect. I.e. when large&#xA;concentrations are present an increase has a small effect, while&#xA;over places with low concentrations small increases have a&#xA;comparatively larger dimming effect. The hypothesis is that, because aerosols cause dimming not only directly, but also indirectly by acting as nuclei for cloud formation, and because cloud characteristics are more heavily affected by increases of such nuclei when their absolute levels are low than when they are already high (i.e. there is a logarithmic relation), small increases in aerosol levels over low-pollution areas can have a significant dimming effect. [See again &lt;a href=&quot;https://journals.ametsoc.org/view/journals/bams/93/1/bams-d-11-00074_1.xml?tab_body=pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wild (2012)&lt;/a&gt;]&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="24481" LastActivityDate="2021-12-10T22:31:37.253" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23283" PostTypeId="1" CreationDate="2021-12-11T00:51:22.253" Score="3" ViewCount="322" Body="&lt;p&gt;I am attempting to determine what the compressive strengths are of the minerals &lt;a href=&quot;https://en.wikipedia.org/wiki/Goethite&quot; rel=&quot;nofollow noreferrer&quot;&gt;goethite&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnetite&quot; rel=&quot;nofollow noreferrer&quot;&gt;magnetite&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;None of the research I did has proven to be fruitful. What I &lt;em&gt;have&lt;/em&gt; found:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;multiple studies regarding what mixing goethite into cement does to the compressive strength of that cement&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;multiple studies regarding the compressive strength of rocks and ores that happen to have some goethite or magnetite in them, alongside other minerals&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;a few studies regarding the usage of magnetite in biomedical implants when combined with other materials&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;multiple studies regarding how goethite effects the mechanical properties of soil, which only mention the mechanical properties and compressive strength of the soil, and not of its individual components&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://royalsocietypublishing.org/doi/10.1098/rsif.2014.1326&quot; rel=&quot;nofollow noreferrer&quot;&gt;one study&lt;/a&gt; involving the goethite found in &lt;a href=&quot;https://en.wikipedia.org/wiki/Limpet#Biomineralization&quot; rel=&quot;nofollow noreferrer&quot;&gt;limpet teeth&lt;/a&gt; that only mentions the tensile strength of said limpet teeth, rather than the compressive strength of goethite&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;no studies or sets of information that actually tell me what the compressive strength of goethite is&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Does anybody know what the compressive strengths of goethite and magnetite are, or have a reliable source of information that I can use to find out?&lt;/p&gt;&#xA;" OwnerUserId="23134" LastEditorUserId="18081" LastEditDate="2021-12-11T13:23:31.463" LastActivityDate="2021-12-11T13:23:31.463" Title="What are the compressive strengths of goethite and magnetite?" Tags="|geochemistry|mineralogy|minerals|reference-request|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23284" PostTypeId="2" ParentId="23283" CreationDate="2021-12-11T04:03:38.343" Score="5" Body="&lt;p&gt;I managed to find &lt;em&gt;&lt;a href=&quot;https://core.ac.uk/download/pdf/297714594.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;EFFECT OF MINERALOGY AND TEXTURE ON THE STRENGTH OF&#xA;IRON ORE&lt;/a&gt;&lt;/em&gt;, which states the uniaxial compressive strength of goethite&#xA;is  157 kg.f/cm&lt;sup&gt;2&lt;/sup&gt;, which &lt;a href=&quot;https://www.theunitconverter.com/kilogram-force-square-centimeter-to-megapascal-conversion/&quot; rel=&quot;nofollow noreferrer&quot;&gt;converts&lt;/a&gt; to 15.397 MPa.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;STRENGTH OF ORE&lt;/p&gt;&#xA;&lt;p&gt;The strength of ore in all the three variants is quite different. Uniaxial compressive strength was found to be 674 kg.f/cm2 for dense martite ore, 254 kg.f/cm2 for microplaty hematite ore and 157 kg.f/cm2 for goethite&#xA;ore. In comparison to the reported data on iron ore, the strength of these variants is low to moderate&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Applying the equation&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;UCS = 1.3672(magnetite percentage) - 3.3093&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;given in Figure 7, in &lt;em&gt;&lt;a href=&quot;http://www.zndxzk.com.cn/down/2018/04_znen/JCSU-11771_12-p0795.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Effect of magnetite content on Bond work index and preconditioning: Case study on Chadormalu iron ore mine&lt;/a&gt;&lt;/em&gt;, for 100 percent magnetite the uniaxial compressive strength would be 133.4 MPa.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2021-12-11T04:39:48.833" LastActivityDate="2021-12-11T04:39:48.833" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23285" PostTypeId="1" CreationDate="2021-12-11T16:33:10.323" Score="5" ViewCount="344" Body="&lt;p&gt;When you read about temperature inversions online, you mostly hear about them trapping pollution in places like Salt Lake City, which is surrounded by mountains. That seems to be the case for most other cities with inversion-related pollution problems, like those in California or China. Clearly the natural barrier of mountains helps trap the cap of warmer air over the cooler air by preventing it from dispersing to the side.&lt;/p&gt;&#xA;&lt;p&gt;Is it possible for a surface temperature inversion to form in areas with a different type of topography?  What conditions would need to be in place in order for a surface temperature inversion to occur outside of a valley or natural bowl?&lt;/p&gt;&#xA;" OwnerUserId="25038" LastEditorUserId="543" LastEditDate="2021-12-11T16:57:46.450" LastActivityDate="2022-01-09T04:12:13.440" Title="Do surface temperature inversions only occur in valleys and natural bowls?" Tags="|meteorology|atmosphere|inversion|planetary-boundary-layer|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23286" PostTypeId="1" CreationDate="2021-12-12T01:44:51.920" Score="5" ViewCount="253" Body="&lt;p&gt;The question is basically the title. I really cannot think of a good reason. Is it a mystery to geologists?&lt;/p&gt;&#xA;" OwnerUserId="20985" LastEditorUserId="21206" LastEditDate="2023-04-11T23:50:15.713" LastActivityDate="2023-04-11T23:50:15.713" Title="Why is the inner core about 85% iron and the rest (mostly) nickel, while the outer is roughly 80%/20%, if nickel is denser than iron?" Tags="|geology|rocks|core|planetary-formation|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23287" PostTypeId="1" CreationDate="2021-12-12T02:21:42.090" Score="4" ViewCount="799" Body="&lt;p&gt;A lower average temperature is, apparently, only part of the answer....&lt;/p&gt;&#xA;&lt;p&gt;Several sites said composition, not temperature, explains most of the difference...&lt;/p&gt;&#xA;&lt;p&gt;And the difference in viscosity can be up to seven orders of magnitude!!!&lt;/p&gt;&#xA;&lt;p&gt;Why?&lt;/p&gt;&#xA;" OwnerUserId="20985" LastActivityDate="2022-02-13T17:23:48.713" Title="Why is felsic (granitic) lava so much more viscous when flowing (or trying to) than mafic (basaltic) lava?" Tags="|geology|volcanology|rocks|volcanic-eruption|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23289" PostTypeId="2" ParentId="23287" CreationDate="2021-12-12T05:14:09.197" Score="2" Body="&lt;p&gt;Partial crystallisation products are the primary factor, iron and magnesium are many times more common in mafic melts than felsic ones. The minerals that are highest in iron and magnesium are the &lt;a href=&quot;https://en.wikipedia.org/wiki/Olivine&quot; rel=&quot;nofollow noreferrer&quot;&gt;olivines&lt;/a&gt; they are also quite soft and slippery due to their microstructure (individual silica tetrahedra that stack together to form grains that don't share any internal atomic bonds) which means they flow more easily past each other in a melt at a given temperature. Felsic melts being much lower in magnesium and iron and relatively higher in sodium, potassium, lithium, and calcium, as well as silicon, have very little olivine and are high in &lt;a href=&quot;https://en.wikipedia.org/wiki/Feldspar&quot; rel=&quot;nofollow noreferrer&quot;&gt;feldspar minerals&lt;/a&gt; which have a very different micro structure (they are composed of long chains of interlinked silica tetrahedra that share atoms similar to polymers but with much higher melting points) and are far less able to flow past and around each other.&lt;/p&gt;&#xA;&lt;p&gt;Due to these differences in chemistry a felsic melt at 1000ᵒC will be many times more viscous than a mafic melt at the same temperature. Add the fact that felsic melts tend to be water saturated and lose a lot of heat when they dehydrate near the surface and so tend to be much colder when observed and they are very viscous indeed. Felsic mineral crystallisations occur at higher temperatures and produce lower heat of crystallisation so felsic melts cool as they set where basalts, and even moreso ultramafic lavas, can actually, initially, increase in temperature as they crystallise.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="20607" LastEditDate="2022-02-13T17:23:48.713" LastActivityDate="2022-02-13T17:23:48.713" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="23290" PostTypeId="1" CreationDate="2021-12-12T08:24:53.810" Score="0" ViewCount="228" Body="&lt;p&gt;When the asteroid that caused the K-T event hit the earth massive amounts of energy was released. In the ideal conditions, is it possible this could have thrown dinosaurs to the space and maybe even to the moon or to other planets? If so, is this likely?&lt;/p&gt;&#xA;" OwnerUserId="25040" LastActivityDate="2021-12-13T04:50:55.503" Title="Did the K-T event throw dinosaurs to the moon?" Tags="|paleontology|" AnswerCount="1" CommentCount="2" ClosedDate="2022-01-16T09:49:17.117" ContentLicense="CC BY-SA 4.0" />
  <row Id="23291" PostTypeId="1" AcceptedAnswerId="23295" CreationDate="2021-12-12T11:24:16.590" Score="5" ViewCount="649" Body="&lt;p&gt;Almost everyone wrongly assumes that the Earth's mantle is liquid, but it isn't (only the outer core is). Is it possible then that there are hollow spaces within the mantle, similar to caves in the crust? What could they look like and up to how much of the mantle could be hollow? What might be inside mantle caverns? Would they be filled with gas or rather vacuum?&lt;/p&gt;&#xA;" OwnerUserId="24914" LastActivityDate="2021-12-13T04:34:45.180" Title="How likely are caverns inside the mantle?" Tags="|plate-tectonics|crust|mantle|cavern|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23293" PostTypeId="1" CreationDate="2021-12-12T21:28:07.167" Score="2" ViewCount="768" Body="&lt;p&gt;As a christmas present, I bought a box of minerals/rocks for my girlfriend, who recently got interested in geology. Unfortunately, she could not attend the identification class in university. The box contains:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;unakite&lt;br /&gt;&#xA;snowflake obsidian&lt;br /&gt;&#xA;red jasper&lt;br /&gt;&#xA;rose quartz&lt;br /&gt;&#xA;rock crystal (quartz)&lt;br /&gt;&#xA;tiger's eye&lt;br /&gt;&#xA;amethyst&lt;br /&gt;&#xA;sodalite&lt;br /&gt;&#xA;magnesite&lt;br /&gt;&#xA;agate&lt;br /&gt;&#xA;aventurine (green)&lt;br /&gt;&#xA;calcite&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I have found some identification flowcharts such as&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oikll.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oikll.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But that is missing, among others, magnesite, the various quartz variations and obviously doesn't contain the non-minerals.&lt;/p&gt;&#xA;&lt;p&gt;I'd like to put together a flow chart so she can identify all those materials. How would one go to identify those rocks and minerals, in a flow-charty-manner?&lt;/p&gt;&#xA;" OwnerUserId="25042" LastActivityDate="2021-12-13T04:39:50.633" Title="Looking for Rock/Mineral Identification Flowchart" Tags="|mineralogy|rocks|identification-request|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23294" PostTypeId="2" ParentId="23291" CreationDate="2021-12-12T23:59:14.717" Score="0" Body="&lt;p&gt;mantle isn't liquid, it is a thixotropic substance that flows when pressure decreases and fluids can flow. If there's huge mineral deposits with high melting points there may be pockets. But caverns need a &amp;quot;Floor&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-12-12T23:59:14.717" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23295" PostTypeId="2" ParentId="23291" CreationDate="2021-12-13T04:34:45.180" Score="1" Body="&lt;p&gt;It is extremely unlikely that any hollow volumes exist in the mantle.&lt;/p&gt;&#xA;&lt;p&gt;The mantle is a convecting solid which can deform over long timescales. Let's assume that such a cavern did somehow form. Whatever it is filled it, would be of lower density than the surrounding rock. It would slowly rise upwards through the solid-yet-deformable mantle until it reaches a place where the rocks are brittle, not ductile. That place is the crust. And as you know, the crust is full of caverns and there is no problem with that.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-12-13T04:34:45.180" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23296" PostTypeId="2" ParentId="23293" CreationDate="2021-12-13T04:39:50.633" Score="1" Body="&lt;p&gt;From my own experience of being a geologist for close to fifteen years, flow charts like that are of very limited use. The truth that you probably did not want to hear, is that it takes years of experience and education to learn how to identify minerals.&lt;/p&gt;&#xA;&lt;p&gt;For example, olivine is defined in your chart as &amp;quot;no streak, cannot be scratched, green, grainy&amp;quot;. I know of many other minerals which are exactly like that (epidote is one example). I also know of olivine which doesn't satisfy these conditions - not all of them are &amp;quot;grainy&amp;quot; (whatever that even means?).&lt;/p&gt;&#xA;&lt;p&gt;You can write a custom flowchart for the minerals in that specific box, but that would be rather boring because most of them are just silica in various forms. Anything more complex than that would lead to false positives and false negatives for anything that slightly deviates from the rubric (which is almost everything).&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-12-13T04:39:50.633" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23297" PostTypeId="2" ParentId="23286" CreationDate="2021-12-13T04:44:40.810" Score="6" Body="&lt;p&gt;Once you're in the metallic part of the Earth, the compositions of the different constituents (solid and liquid) are not determined by density.&lt;/p&gt;&#xA;&lt;p&gt;The whole metallic part (core) is denser the the silicate rock part (mantle) which is why it is the core.&lt;/p&gt;&#xA;&lt;p&gt;The concentrations of various elements in the solid vs the liquid are determined by thermodynamics and equilibrium partitioning. In a very simple sense, if you melt an iron-nickel alloy, it doesn't all melt at once. It melts continuously over an increasing temperature range, with coexisting liquid and solid. The solid will always have a bit more iron, and the liquid always a bit more nickel, until it is all liquid.&lt;/p&gt;&#xA;&lt;p&gt;The core is a bit more complicated than that, but the general principle still holds.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-12-13T04:44:40.810" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23298" PostTypeId="2" ParentId="23290" CreationDate="2021-12-13T04:50:55.503" Score="4" Body="&lt;p&gt;We know that there are probably terrestrial meteorites on the Moon, which got there because of impacts on Earth sending debris flying. So asking whether dinosaurs ended up on the Moon is a legitimate question.&lt;/p&gt;&#xA;&lt;p&gt;The answer, however, is probably a &lt;strong&gt;no&lt;/strong&gt;. The things that were flown to space were rocks, which can survive an impact and high temperatures. Dinosaurs close enough to the impact to be theoretically launched into space would most like completely disintegrate and vaporise in an instant, and not survive in recognisable dinosaur form all the way to space.&lt;/p&gt;&#xA;&lt;p&gt;Yes, it is possible that some of the dust that landed on the moon may contain remnants of dinosaurs or other living things (among mostly other inanimate things), but calling them &amp;quot;dinosaurs&amp;quot; is a bit of a stretch.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-12-13T04:50:55.503" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23299" PostTypeId="2" ParentId="23287" CreationDate="2021-12-13T04:56:28.810" Score="7" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Several sites said composition, not temperature, explains most of the&#xA;difference...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;They are correct. All other factors remaining equal, felsic magmas are more viscous. This is the result of higher silica (SiO&lt;sub&gt;2&lt;/sub&gt;) contents in the melt.&lt;/p&gt;&#xA;&lt;p&gt;In melts and rocks, silicon atoms are (almost) always surrounded by four oxygen atoms in tetrahedral shape. These tetrahedrons have an extremely strong affinity to bond to each other, forming a polymerised network of silica tetrahedrons.&lt;/p&gt;&#xA;&lt;p&gt;More silica = better capacity to form the polymerised network. Increasing silica contents also make each instance of silica polymer bigger and longer.&lt;/p&gt;&#xA;&lt;p&gt;When you have a low silica melt (basalt) those polymerised silica networks are tiny and not well connected, so moving them around is easy. Once they grow bigger, it becomes much harder for them to move. So the viscosity goes up.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2021-12-13T04:56:28.810" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23300" PostTypeId="1" AcceptedAnswerId="23303" CreationDate="2021-12-13T05:26:28.187" Score="4" ViewCount="70" Body="&lt;p&gt;I am very new to the study of the cryosphere. I was looking at the GLIMS inventory for glaciers and observed red patches as shown below which the legend mentions the red patches as internal rocks. In my limited understanding internal rocks are  frozen debris that have hardened over many years ? Is this correct ?&#xA;Secondly, how are these rocks inside the glacier determined ?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WYLo3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WYLo3.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24972" LastActivityDate="2021-12-13T18:09:08.277" Title="Internal rocks in glaciers" Tags="|rocks|glaciology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23301" PostTypeId="2" ParentId="23286" CreationDate="2021-12-13T06:42:07.723" Score="3" Body="&lt;p&gt;When they are molten these metals dissolve within each other - ie they are in &lt;a href=&quot;https://en.wikipedia.org/wiki/Solution_(chemistry)&quot; rel=&quot;nofollow noreferrer&quot;&gt;solution&lt;/a&gt;. Convection and diffusion will disperse and mix them; convection and accompanying turbulence mixes them at large scale and diffusion causes migration from high concentrations to low at small scale. Near a planet's core the gravity gradient is going to be limited, ie separation due to differential density is not a strong phenomena and the inner core itself is believed to be solid; there is mixing within the fluid outer core but no ongoing convection or mixing with or within the inner core.&lt;/p&gt;&#xA;&lt;p&gt;The inner core would have higher iron content due to ongoing radioactive decay and lack of ongoing mixing, ie it is the oldest and given enough time the other metals  in it including nickel transmute through natural radioactive decay - Nickel-56 beta-decays to Iron-56 (via cobalt-56) - with iron being the stable end product. Over time there will be less nickel and more iron.&lt;/p&gt;&#xA;&lt;p&gt;(Note - I &lt;em&gt;suspect&lt;/em&gt; that solid crystals don't form in molten nickel-iron until temperatures where viscosity impedes sedimentation and the crystals will be mostly taenite and kamacite - ie nickel-iron - rather than crystals of iron separate from crystals of nickel.)&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2021-12-13T06:42:07.723" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23302" PostTypeId="1" CreationDate="2021-12-13T11:29:19.390" Score="1" ViewCount="43" Body="&lt;p&gt;In the following image (from &lt;a href=&quot;https://www.space.com/8596-earth-colorful-atmospheric-layers-photographed-space.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt;)&lt;a href=&quot;https://i.stack.imgur.com/R1DlA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/R1DlA.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;they claim the orange part is the troposphere, the yellow/almost white part is the stratosphere and the light blue part obviously the mesosphere while those above would be the mesopause and the thermosphere.&lt;/p&gt;&#xA;&lt;p&gt;I'm pretty sure they got it wrong.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;What is considered the &amp;quot;stratosphere&amp;quot; is far too small to be the stratosphere, even if excluding the &lt;a href=&quot;https://earthscience.stackexchange.com/questions/23196/why-is-the-isothermal-layer-being-considered-a-part-of-the-stratosphere-rather-t&quot;&gt;isothermal layer&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;The alleged stratosphere has clouds in it, hence it can't be it nor even the isothermal layer alone. The &amp;quot;stratosphere&amp;quot; in the image is still part of the very troposphere and the difference in colors seems to be due to the different cloud layers only. In fact you can see to the very right that there's little difference between the alleged &amp;quot;stratosphere&amp;quot; and the troposphere; it seems to be one and the same layer.&lt;/li&gt;&#xA;&lt;li&gt;I guess that in fact the layer(s) called &amp;quot;troposphere&amp;quot; and &amp;quot;stratosphere&amp;quot; are both the troposphere (up to ~12 km (7.5 mi)), the light blue layer is the isothermal stratosphere layer (12-20 km (12.5 mi)) and the very dark blue layer above is the rest of the stratosphere (above 20 km to above 25 km (15.5 mi) depending on the latitude).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;What are your thoughts on this and how do the layers compare to those in the images &lt;a href=&quot;https://earthscience.stackexchange.com/questions/23189/what-layers-of-the-atmosphere-are-divided-in-this-image-by-abrupt-borders&quot;&gt;in my other question&lt;/a&gt; where they're imaged in broad daylight, not during sunset?&lt;/p&gt;&#xA;" OwnerUserId="24914" LastActivityDate="2021-12-13T11:29:19.390" Title="Didn't they get the atmospheric layers wrong in this image and which layers are those actually?" Tags="|atmosphere|troposphere|stratosphere|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23303" PostTypeId="2" ParentId="23300" CreationDate="2021-12-13T18:09:08.277" Score="4" Body="&lt;p&gt;Although glacier data is acquired via satellite, a lot of painstaking manual interpretation must, among many other things, separate glacier from snowfield, simple debris field from debris covered glacier. All of these qualifiers go into the GLIMS GIS database that makes it possible to measure real glacier behavior over time, without actually having to get on the glacier itself every summer with a tape measure and notepad.&lt;/p&gt;&#xA;&lt;p&gt;When manually delineating glacier outlines (AKA polygons) a GLIMS analyst may include rock outcrops that are entirely within a single glacier. As per p.8 of &lt;a href=&quot;https://www.glims.org/MapsAndDocs/assets/GLIMS_Analysis_Tutorial_a4.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;GLIMS Analysis Tutorial&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;To create an outline that conforms to the above definition, one should&#xA;create one polygon (or series of segments) that circumscribes the&#xA;entire glacier.  Internal rock outcrops are excluded by producing&#xA;outlines around them and labeling those outlines as internal rock.&#xA;This can be done simply in GLIMSView, or can be done with other tools.&#xA;In the resulting “segments” shapefile, the “category” attribute should&#xA;be “intrnl_rock” for internal rock segments.  Internal rock polygons&#xA;should be separate polygons (or collections of segments), not&#xA;sub­parts of multi­part polygons. Other separate polygons can be used&#xA;for supraglacial lakes or debris cover.  Glacier outlines should be of&#xA;glacier boundaries, not basin boundaries.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/D11Fg.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/D11Fg.jpg&quot; alt=&quot;&amp;quot;Internal rock&amp;quot; polygons should only be&#xA;included if the outcrop is completely internal to&#xA;one glacier.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;Figure 2: &amp;quot;Internal rock&amp;quot; polygons should only be included if the&lt;/strong&gt;&lt;/em&gt;&#xA;&lt;em&gt;&lt;strong&gt;outcrop is completely internal to one glacier.&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In your example, the red &amp;quot;internal rock&amp;quot; appears to be entirely surrounded by a single glacier, not uncommon where a steep rock face on a mountain is entire surrounded by ice.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2021-12-13T18:09:08.277" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23304" PostTypeId="1" AcceptedAnswerId="23327" CreationDate="2021-12-13T22:57:55.990" Score="2" ViewCount="185" Body="&lt;p&gt;Call it hair splitting, if you want, but I see at least three numbers in the latest IPCC report (e.g. on pages 7-51–7-52). The first one, &amp;quot;the total human forced GSAT change from 1750–2019&amp;quot;, is 1.29°C. The second one, &amp;quot;the total (anthropogenic plus natural) emulated GSAT between 1850–1900 and 2010–2019&amp;quot;, is 1.14°C. The third one, &amp;quot;the assessed GSAT&amp;quot;, is 1.06°C. Suppose, the second one is a simulation and the third one is an observation (or so I understood). But why is the first estimate considerably higher than the second one even though the former doesn't include small natural warming, I take it? Keep in mind, 1750 and 1850 are almost the same baselines and differ by a measly 0.1°C so it doesn't explain the discrepancy. I'm not a science skeptic, by the way&lt;/p&gt;&#xA;" OwnerUserId="22632" LastActivityDate="2021-12-18T15:11:33.120" Title="How much has Earth warmed since preindustrial times, after all?" Tags="|climate-change|" AnswerCount="3" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23305" PostTypeId="1" CreationDate="2021-12-13T23:10:33.150" Score="1" ViewCount="102" Body="&lt;p&gt;The latest IPCC report basically says that whatever we do, NY is a doomed city with no hope to remain above water due to climate change (among many other settlements) (TS-54). Why is the media not freaking out? I don't recall anyone mentioning it since the report was released. Did I misinterpret the figures? For example, Baku is 28 meters below sea level but not submerged so there's more to that than plain elevation numbers, I guess&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iXUys.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iXUys.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22632" LastEditorUserId="22632" LastEditDate="2021-12-14T01:25:43.877" LastActivityDate="2021-12-14T22:47:31.283" Title="Is New York bound to go underwater?" Tags="|climate-change|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="23306" PostTypeId="2" ParentId="23285" CreationDate="2021-12-14T01:01:26.920" Score="3" Body="&lt;p&gt;Valleys and basins make surface temperature inversions (STI) easier to form and harder to disperse. However, an STI is the result of warm air sitting above colder air can form independently of orographic constraints:&lt;/p&gt;&#xA;&lt;p&gt;Turbulence Inversion: A poorly understood stratification of warm air over colder air when very light wind eddies fail to interact and vertically mix with surface air. These can form over flat, non-mountainous terrain.&lt;/p&gt;&#xA;&lt;p&gt;Frontal Inversion: A large, cold air mass wedges itself under a stable high pressure system; these are more related to fast moving, unstable weather systems. On that note, continental scale weather systems may also produce...&lt;/p&gt;&#xA;&lt;p&gt;Subsidence Inversion: Forms when a descending high-pressure system compresses an air mass far enough to cool it relative to the mass above.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2021-12-14T01:01:26.920" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23307" PostTypeId="1" CreationDate="2021-12-14T02:02:20.230" Score="5" ViewCount="31" Body="&lt;p&gt;I've been having this burning question about the tropical climate of Pangaea but not sure how to ask until now.&lt;/p&gt;&#xA;&lt;p&gt;So far I've read that the carbon dioxide levels back then were much higher than it is now ( about &lt;a href=&quot;https://eos.org/articles/a-dip-in-atmospheric-carbon-may-have-facilitated-dinosaur-dispersal&quot; rel=&quot;noreferrer&quot;&gt;2000 - 4000 ppm&lt;/a&gt; ) and the fact that coastal regions around the Tethys ocean were constantly affected by super hurricanes and extreme monsoons ( due to the warm currents coming from Panthalassa ocean and the contiguous landmass of Pangaea ).&lt;/p&gt;&#xA;&lt;p&gt;Would it be hotter and more humid than today's tropical regions ? Or would the region experience extreme changes in temperature and humidity throughout the day ?&lt;/p&gt;&#xA;" OwnerUserId="25046" LastActivityDate="2021-12-14T02:02:20.230" Title="What was the weather like in Pangaea's equatorial regions ( i.e. 23 latitude North to 23 latitude South )?" Tags="|meteorology|climate|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23308" PostTypeId="2" ParentId="23263" CreationDate="2021-12-14T13:07:12.033" Score="2" Body="&lt;p&gt;An important distinction is &lt;a href=&quot;https://geomag.bgs.ac.uk/education/poles.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;what kind of magnetic pole we're talking about&lt;/a&gt;. The &amp;quot;exact direction of Earth's magnetic poles&amp;quot;, would be the dip poles, and no, we can't determine these as we have too little information. The rough approximation of the field in terms of the geomagnetic dipoles though we can do.&lt;/p&gt;&#xA;&lt;p&gt;With a single measurement alone the problem is non-unique (more than one shape of magnetic field could produce any given measurement at a single point in space and time).&lt;/p&gt;&#xA;&lt;p&gt;That said, a lot of paleomagnetism relies on assuming that Earth's field has always been predominantly a dipole. So with this assumption you can use paleomagnetic field direction measurements to estimate the magnetic dipole latitude of the sampled rock, and thus the location of the geomagnetic dipole at that time.&lt;/p&gt;&#xA;&lt;p&gt;So you can estimate the geomagnetic dipole location from a dated paleomagnetic rock sample. The other way round is possible but it's a chicken-egg situation - you don't know what the paleomagnetic field should look like at a particular time without having measurements from dated rocks to infer this already, and there may be multiple times and places that a measurement would fit.&lt;/p&gt;&#xA;&lt;p&gt;And &lt;em&gt;paleomagneticist&lt;/em&gt; is a valid (hard to spell) term, though some may prefer the way cooler sounding &lt;em&gt;paleomagician&lt;/em&gt;...&lt;/p&gt;&#xA;" OwnerUserId="14123" LastActivityDate="2021-12-14T13:07:12.033" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23309" PostTypeId="1" CreationDate="2021-12-14T13:09:59.947" Score="5" ViewCount="209" Body="&lt;p&gt;We know the Global Mean Temperature is increasing due to climate change. But for the Global Mean Atmosphere Pressure, can we see an obvious trend?&lt;/p&gt;&#xA;" OwnerUserId="25051" LastEditorUserId="111" LastEditDate="2021-12-14T13:28:18.420" LastActivityDate="2022-01-29T15:19:05.900" Title="Is Global Mean Surface Atmosphere Pressure changed long-term by global warming?" Tags="|meteorology|climate-change|atmosphere|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23310" PostTypeId="2" ParentId="23305" CreationDate="2021-12-14T22:47:31.283" Score="1" Body="&lt;p&gt;New Yorkers see the writing on the wall and ARE freaking out over rising sea levels...but not in the expected way. Ever since the last (2013) redrawing of federal FEMA flood maps that accounted for coming sea level rise, the threat of rising insurance rates forced the city to argue against the science used by FEMA. As a result, FEMA backed away, watering down (!) flood risks to appease concerns that property values would decrease and that the poor would get shafted.&lt;/p&gt;&#xA;&lt;p&gt;Updated FEMA maps due out sometime in 2022 will be backed by ironclad science that the city cannot argue against. You can be assured that many coastal New Yorkers with mortgages will be freaking out when they see their mandatory insurance bills rise by many thousands of dollars. They are already pre-freaking out!&lt;/p&gt;&#xA;&lt;p&gt;Inland New Yorkers are also freaking out that these potentially displaced coastal communities will further add to the city's housing crisis, and that's ahead of the next storm surge. This, in addition to the stress of living with all of the work being undertaken to harden municipal systems ahead of rising tides.&lt;/p&gt;&#xA;&lt;p&gt;As for the media, they only understand &amp;quot;if it bleeds, it ledes&amp;quot;; they think that nothing puts viewers to sleep faster than news stories about neighborhood re-zoning and insurance premiums.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2021-12-14T22:47:31.283" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23311" PostTypeId="1" CreationDate="2021-12-14T23:22:17.597" Score="2" ViewCount="49" Body="&lt;p&gt;&amp;quot;Extinction Debt&amp;quot; describes the delayed disappearance of a species following some geologically fast change in an earth system that cannot be escaped. For example, it might takes years of this extinction debt following shoreline submergence to kill off some species of mollusk.&lt;/p&gt;&#xA;&lt;p&gt;Likewise, the re-routing of winter jet-streams over the deserts watersheds of the American Southwest may lead to the total disappearance of many native fishes.&lt;/p&gt;&#xA;&lt;p&gt;These are obvious examples of species potentially living with extinction debt. What are other examples where a species, or entire ecosystem, is currently alive but whose fate is already sealed by some fast moving earth system change?&lt;/p&gt;&#xA;" OwnerUserId="7333" LastEditorUserId="7333" LastEditDate="2021-12-23T17:10:14.810" LastActivityDate="2021-12-23T17:10:14.810" Title="How, and where, are the unusual occurences of extinction debt playing out?" Tags="|earth-system|evolution|" AnswerCount="0" CommentCount="3" ClosedDate="2021-12-17T19:37:26.580" ContentLicense="CC BY-SA 4.0" />
  <row Id="23313" PostTypeId="2" ParentId="16777" CreationDate="2021-12-15T20:24:06.527" Score="1" Body="&lt;p&gt;Assuming a surface ocean temperature of 288 K and a deep ocean temperature of 277 K, let's assume a mean temperature around 282.5 K.&lt;/p&gt;&#xA;&lt;p&gt;The specific heat capacity of seawater at constant pressure is 3,890 joules per kilogram per kelvin.&lt;/p&gt;&#xA;&lt;p&gt;The mass of the ocean is 1.39 x 10&lt;sup&gt;21&lt;/sup&gt; kg.&lt;/p&gt;&#xA;&lt;p&gt;Therefore the &amp;quot;thermal content,&amp;quot; if I can call it that, of the ocean is 1.528 x 10&lt;sup&gt;27&lt;/sup&gt; J.  At 281.5 K, it would be 1.522 x 10&lt;sup&gt;27&lt;/sup&gt; J.  The difference is 5.407 x 10&lt;sup&gt;24&lt;/sup&gt; J using all the significant figures Excel gives me.  That's a lot of energy!&lt;/p&gt;&#xA;" OwnerUserId="12453" LastEditorUserId="2470" LastEditDate="2021-12-15T21:36:49.030" LastActivityDate="2021-12-15T21:36:49.030" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23314" PostTypeId="1" CreationDate="2021-12-16T07:21:28.880" Score="6" ViewCount="55" Body="&lt;p&gt;If the Earth's atmosphere is warming it has to expand. Can we measure an increasing thickness of the troposphere?&lt;/p&gt;&#xA;" OwnerUserId="26060" LastEditorUserId="2470" LastEditDate="2021-12-16T15:25:45.537" LastActivityDate="2021-12-16T15:25:45.537" Title="Is the troposphere expanding?" Tags="|atmosphere|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23315" PostTypeId="1" AcceptedAnswerId="23316" CreationDate="2021-12-16T11:53:47.590" Score="8" ViewCount="1489" Body="&lt;p&gt;&lt;a href=&quot;https://www.bbc.co.uk/bitesize&quot; rel=&quot;nofollow noreferrer&quot;&gt;BBC Bitesize&lt;/a&gt; defines &lt;em&gt;primary consumers&lt;/em&gt; as the following, implying that (if I've interpreted this correctly) the term includes &lt;strong&gt;any&lt;/strong&gt; animal that feeds on the primary producer — plants:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This refers to organisms that eat the producer. &lt;strong&gt;Most are herbivores.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;However, this is contradicted by the &lt;a href=&quot;https://www.nationalgeographic.org/encyclopedia/consumers/#:%7E:text=Primary%20consumers%20make%20up%20the%20second%20trophic%20level.%20They%20are%20also%20called%20herbivores.&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Geographic Society&lt;/a&gt; which defines it as:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Primary consumers make up the second trophic level. &lt;strong&gt;They are also called herbivores&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Which is it? Are primary consumers &lt;strong&gt;exclusively&lt;/strong&gt; herbivores, or does/can the term include any animal that feeds on the primary producer in the food chain we're looking at?&lt;/p&gt;&#xA;" OwnerUserId="23287" LastEditorUserId="23287" LastEditDate="2021-12-17T01:54:20.363" LastActivityDate="2021-12-22T03:23:04.373" Title="Should a primary consumer always be a herbivore?" Tags="|ecology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23316" PostTypeId="2" ParentId="23315" CreationDate="2021-12-16T13:45:07.460" Score="9" Body="&lt;p&gt;Not always. One good example is the food web around a &lt;a href=&quot;https://oceanservice.noaa.gov/facts/vents.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;hydrothermal vent&lt;/a&gt;. In the vent system, bacteria use chemical energy from hydrogen sulfide to produce sugars without any sunlight (no photosynthesis). Then, some animals (e.g., zooplankton) around the vent feed on the bacteria (primary consumers), while others feed on the primary consumers (secondary consumers). &lt;a href=&quot;http://www.forsea.org/wp-content/uploads/2019/08/F9U510TGST.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here is an example activity that touches on this food web.&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/JXrEj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JXrEj.jpg&quot; alt=&quot;Food web for hydrothermal vents&quot; /&gt;&lt;/a&gt;&#xA;Source: &lt;a href=&quot;https://prezi.com/enzc3iqcvizk/hydrothermal-vent-ecosystem/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://prezi.com/enzc3iqcvizk/hydrothermal-vent-ecosystem/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;To add something about primary consumers being any organism that feeds on producers. The whole idea of classifying consumers is a bit bogus. Classifying producers is way clearer because you can clearly look at photosynthetic or chemosynthetic organisms and go from there. The way that we can look at consumers is based on their &lt;span class=&quot;math-container&quot;&gt;$\delta &#xA; ^{13}C$&lt;/span&gt; (&lt;a href=&quot;http://en.wikipedia.org/wiki/%CE%9413C&quot; rel=&quot;nofollow noreferrer&quot;&gt;en.wikipedia.org/wiki/%CE%9413C&lt;/a&gt;) and &lt;span class=&quot;math-container&quot;&gt;$\delta  ^{15}N$&lt;/span&gt; (&lt;a href=&quot;http://en.wikipedia.org/wiki/%CE%9415N&quot; rel=&quot;nofollow noreferrer&quot;&gt;en.wikipedia.org/wiki/%CE%9415N&lt;/a&gt;). As you move up trophic level, your proportion of &lt;span class=&quot;math-container&quot;&gt;$\delta  ^{13}C$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\delta  ^{15}N$&lt;/span&gt; increases.&#xA;Even for humans, depending on how much meat you eat you get different signals (e.g., &lt;a href=&quot;http://en.wikipedia.org/wiki/%CE%9415N&quot; rel=&quot;nofollow noreferrer&quot;&gt;pnas.org/content/117/33/20044&lt;/a&gt;, Figure 1). In your case, the omnivore will have a signal that includes higher &lt;span class=&quot;math-container&quot;&gt;$\delta  ^{15}N$&lt;/span&gt; values because of their feeding on other animals and therefore they will be classified as a secondary consumer.&#xA;In order for omnivores to be classified as a primary consumer, their &lt;span class=&quot;math-container&quot;&gt;$\delta  ^{15}N$&lt;/span&gt; should be close to the one for producers or better to organisms with a complete &amp;quot;vegetarian&amp;quot; diet. That is not the case for omnivores.&#xA;In a lot of these cases, there is a gradient of values of &lt;span class=&quot;math-container&quot;&gt;$\delta  ^{15}N$&lt;/span&gt; depending on the diet of the specific omnivore. In fact, scientists look at the &lt;span class=&quot;math-container&quot;&gt;$\delta  ^{15}N$&lt;/span&gt; values of different individuals to determine their eating habits and in some cases where in the habitat they are feeding. There is a lot of variability on this depending on organisms and even life stages. Classifying organisms as primary/secondary consumers misses the nuance and oversimplifies the complex food web that we observed in the environment.&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2021-12-22T03:23:04.373" LastActivityDate="2021-12-22T03:23:04.373" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23317" PostTypeId="1" CreationDate="2021-12-16T16:43:51.893" Score="5" ViewCount="37" Body="&lt;p&gt;I have been tasked with proof reading before publication a Russian paper that has been translated into basic English and am searching for a word to describe the area of a glacial valley where the valley sides transitions into the valley floor?&lt;/p&gt;&#xA;" OwnerUserId="25037" LastEditorDisplayName="user20559" LastEditDate="2021-12-17T17:06:13.783" LastActivityDate="2021-12-17T17:06:13.783" Title="I am searching for a word to describe the area of a glacial valley where the sides transition into the floor?" Tags="|geology|glaciology|geomorphology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23318" PostTypeId="2" ParentId="23317" CreationDate="2021-12-16T22:16:02.840" Score="1" Body="&lt;p&gt;Others may know if there is specific term for what you are asking. In case there isn't the following may help.&lt;/p&gt;&#xA;&lt;p&gt;The walls of a valley are slopes - some are steeply dipping while others are shallow dipping. The top of a slope, whether natural or engineered, is called the crest of the slope and the bottom of a slope, where it meets the floor is called the toe of the slope.&lt;/p&gt;&#xA;&lt;p&gt;Where the toe is not sharply defined and the slope transitions into the floor I would call that a transition toe.&lt;/p&gt;&#xA;&lt;p&gt;The other term than is sometime used, instead of toe, in reference to continental slopes is foot.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-12-16T22:16:02.840" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23319" PostTypeId="2" ParentId="23304" CreationDate="2021-12-17T00:38:14.390" Score="2" Body="&lt;p&gt;There has been a component of natural cooling over that period - not warming. 1.14C is the modeled  amount of warming overall, which comes from 1.29C of anthropogenic, less 0.15 of natural cooling. There appears about 0.8C of difference between modeled and assessed from actual temperature data - which is almost certainly within the expected range of uncertainty (which were not provided here).&lt;/p&gt;&#xA;&lt;p&gt;It would be more remarkable for modeling and temperature data to work out exactly the same than being a bit different, but within the ranges of uncertainty.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2021-12-17T00:38:14.390" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23320" PostTypeId="1" AcceptedAnswerId="23323" CreationDate="2021-12-17T03:02:10.550" Score="1" ViewCount="93" Body="&lt;p&gt;Can &lt;a href=&quot;https://en.wikipedia.org/wiki/Tornado&quot; rel=&quot;nofollow noreferrer&quot;&gt;tornadoes&lt;/a&gt; be predicted or forecasted using supercomputers?&lt;/p&gt;&#xA;" OwnerUserId="21250" LastEditorUserId="6298" LastEditDate="2021-12-17T11:39:49.347" LastActivityDate="2021-12-18T06:59:58.773" Title="Tornado prediction or forecasting by supercomputers" Tags="|weather-forecasting|atmosphere-modelling|tornado|" AnswerCount="2" CommentCount="2" ClosedDate="2022-01-04T14:01:09.690" ContentLicense="CC BY-SA 4.0" />
  <row Id="23321" PostTypeId="2" ParentId="23320" CreationDate="2021-12-17T16:34:29.120" Score="4" Body="&lt;p&gt;Honestly, such a question is almost like &amp;quot;what is the meaning of life.&amp;quot; It is a very loaded question in a single sentence.&lt;/p&gt;&#xA;&lt;p&gt;I'll start with tackling the issue of supercomputers. I think people put too much stock into supercomputers. &amp;quot;Can supercomputers do xyz?&amp;quot; is not a good question for several reasons.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;There is a fundamental misunderstanding of what supercomputers are. Supercomputers are essentially a bunch of computers that tag-team to tackle large problems that an individual computer cannot handle. As a result, a supercomputer is programmed similar to how one programs a normal computer. So it isn't a matter of what a supercomputer can do, rather what methods a human mind can conceive of and implement into a supercomputer. Then, it can be asked whether the supercomputer can handle the method.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;We have supercomputers. Supercomputers can simulate the weather using weather models, specialized software for meteorology. If the simulations can be done before the event occurs, it can be used for prediction. However the intense cost for simulating tornadoes make the settings only applicable for research.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Now there is another issue for your question- what do you mean by predicted or forecasted? As I said, there are weather models that simulate the weather, and those models can use &lt;a href=&quot;https://www.spc.noaa.gov/publications/thompson/stp_scp.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;researched equations&lt;/a&gt; that estimate the atmosphere's ability to develop tornadoes over an area at a certain time. But when you say forecast or predict, are you asking for individual tornadoes? Accuracy is a large portion of predictability. If a tornado is 5 km off from the prediction, is that a bad forecast? Even from observations (here in the U.S.) &lt;a href=&quot;https://www.usatoday.com/in-depth/news/nation/2021/06/16/tornado-warning-system-has-come-long-way-but-could-better/5152104001/&quot; rel=&quot;nofollow noreferrer&quot;&gt;it is hard to even tell that a tornado is imminent greater than 9 minutes ahead of time&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I can go on and on. Other issues to consider are&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;You need to predict severe weather before you predict tornadoes.&lt;/li&gt;&#xA;&lt;li&gt;The lead time for the prediction.&lt;/li&gt;&#xA;&lt;li&gt;The amount of time and effectiveness in communicating the prediction.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;But I'll finish with this last note. My last complaint about your question is that it doesn't question the current capacity explicitly, but questions future capacity. Nobody short of a time-traveler can definitively say that someone using a supercomputer &lt;strong&gt;can never&lt;/strong&gt; predict a tornado. So there is no good answer to your question.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2021-12-17T16:34:29.120" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23322" PostTypeId="1" CreationDate="2021-12-17T18:40:55.130" Score="3" ViewCount="132" Body="&lt;p&gt;If I have a four band Landsat 8 image (Blue, Green, Red and NIR) and pansharpen this image using the panchromatic band. How accurate would the pansharpening be for the Blue and NIR bands? See band designations in attached image.&lt;/p&gt;&#xA;&lt;p&gt;I would appreciate incites in this matter and also if I could find published literature on this subject.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YZaJq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YZaJq.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14152" LastActivityDate="2022-01-19T17:03:55.260" Title="Pansharpening of Landsat 8" Tags="|remote-sensing|satellites|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23323" PostTypeId="2" ParentId="23320" CreationDate="2021-12-18T06:59:58.773" Score="0" Body="&lt;p&gt;No. Even with Petaflop scale supercomputers, tornadoes and other storm phenomena are not &amp;quot;Predictable&amp;quot;, often weather data in live/real time is offset to assess a storm&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Lower-ing pressure&lt;/li&gt;&#xA;&lt;li&gt;wind speed rising faster than established norms&lt;/li&gt;&#xA;&lt;li&gt;Humidity rising&#xA;Many people near a tornado tell of their ears &amp;quot;popping&amp;quot; due to the pressure change.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-12-18T06:59:58.773" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23324" PostTypeId="2" ParentId="23304" CreationDate="2021-12-18T07:02:53.033" Score="-2" Body="&lt;p&gt;About 1 degree Celsius since the 1850s. That's up from a another one since the 1600's. Earth's temperature rose about 1.5- degrees since the 1700's.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/mtTZ4.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mtTZ4.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;If you want a good guess, use the CET since 1659. NOTE the temperature curve, failed to obey the CO2 curve.&#xA;Average temperatures are hard to come by largely because corrupted data from temperature data from weather stations placed in poor locations..... Subtract Urban heat island effect it spits in eye of climate alarmists. And many temp sensors are in cities, thou cities only make up 2.7% landscape they have vast majority of data sets.&#xA;Outliers often Always offset averages, Urban heat islands affect, even at nighttime temps; An asphalt parking lot can store a days worth of solar energy and heat air an added 10 degrees in daytime, 2-5 degrees at night. Contaminated temperature data come from temperature sensors and weather stations in parking lots and urban building zones.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/RHYto.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RHYto.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/6cGYL.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6cGYL.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastEditorUserId="21028" LastEditDate="2021-12-18T07:09:34.273" LastActivityDate="2021-12-18T07:09:34.273" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23325" PostTypeId="2" ParentId="16777" CreationDate="2021-12-18T07:17:49.097" Score="1" Body="&lt;p&gt;&lt;em&gt;&lt;strong&gt;Heat capacity&lt;/strong&gt;&lt;/em&gt; is the amount of thermal energy it requires to heat a gram of &amp;quot;A substance&amp;quot; one Kelvin degree.&#xA;Salt water of oceanic variant average salinity (3.5%) has specific heating of 3.993 J/(g K) or 3.993 Joules of energy per gram of water to raise it ONE degree kelvin.&lt;/p&gt;&#xA;&lt;p&gt;using Metric; Water has a specific heat capacity of 4.186 J/g°C, meaning that it requires 4.186 J of energy (1 calorie) to heat a gram by one degree Celsius. With an Oceanic volume of 321 Million Cubic miles (1.338 Quintillion! cubic meters) with roughly one million grams of water per cubic meter it would take the removal of&#xA;nearly a Yottajoules worth of energy, 500 TIMES current human annual energy consumption.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2021-12-18T07:17:49.097" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23326" PostTypeId="1" CreationDate="2021-12-18T15:02:46.473" Score="2" ViewCount="215" Body="&lt;p&gt;It seems there is a greater variation in temperature during summer than during winter (image: maximal and minimal temperatures in Britain - &lt;a href=&quot;http://projectbritain.com/climate.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GUJ3P.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GUJ3P.png&quot; alt=&quot;http://projectbritain.com/climate.html&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;My hypothesis is that this is because there's a greater humidity in the winter (&lt;a href=&quot;https://www.researchgate.net/publication/344649076_Ventilation_in_Architecture_and_Planning_K14VAP_MSc_Renewable_Energy_and_Architecture/figures?lo=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt; - Iran) because in the summer, more water evaporates and forms clouds which means there's less water in the air that would absorb energy from the Sun. Am I correct?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8KI6x.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8KI6x.png&quot; alt=&quot;https://www.researchgate.net/publication/344649076_Ventilation_in_Architecture_and_Planning_K14VAP_MSc_Renewable_Energy_and_Architecture/figures?lo=1&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5016" LastEditorUserId="5016" LastEditDate="2021-12-20T13:00:00.733" LastActivityDate="2021-12-20T13:00:00.733" Title="Is there a bigger diurnal temperature variation in the summer because of a greater humidity?" Tags="|temperature|humidity|seasons|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23327" PostTypeId="2" ParentId="23304" CreationDate="2021-12-18T15:11:33.120" Score="6" Body="&lt;p&gt;Some of the relevant AR6 headline values are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;+1.09 °C = Observed GMST and GSAT change between the periods 1850-1900 and 2011-2020&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;+1.06 °C = Observed GMST and GSAT change between the Chapter 7 attribution assessment periods 1850-1900 and 2010-2019&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;+1.14 °C = Emulated GSAT change between the Chapter 7 attribution assessment periods 1850-1900 and 2010-2019&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;+1.29 °C = Emulated GSAT change between end points 1750 and 2019, attributed to anthropogenic forcings&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The +1.06 °C and +1.09 °C values are the same observed estimates of temperature change, it’s just that the latter covers the most recent “current” period that was available at the time the report was being written.  Yes, the 0.03 °C difference comes from only one year of difference in the meaning periods, but that just reflects the effect of interannual variability on 10-year means.  The +1.06 °C value is only really included in the report for comparison with the work in Chapter 7.&lt;/p&gt;&#xA;&lt;p&gt;The +1.06 °C and +1.14 °C values are two different estimates of the same GSAT metric.  They're not independent estimates because the latter is constrained by the GSAT observations, as well as other observations and models.  When you consider their uncertainty bounds, these estimates are consistent with each other, but, as noted in Chapter 7 p7-52:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;As the emulated response attempts to constrain to multiple lines of evidence (Supplementary Material 7.SM.2), only one of which is GSAT, they should not necessarily be expected to exactly agree.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The GSAT observations tell us what happened, but they don’t tell us why it happened: how much does each forcing agent contribute to the record?  In theory we could estimate these contributions by running full ESMs many many times, covering uncertainty in the forcing agents, perhaps also constrained by observations and their uncertainties, in an attempt to see the signals through the noise of internal variability.  But in practice, it’s just not computationally possible to do that, which is where the emulators come in.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Cross-Chapter Box 7.1&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Climate model emulators are simple physically-based models that are used to approximate large-scale climate responses of complex Earth System Models (ESMs). Due to their low computational cost they can populate or span wide uncertainty ranges that ESMs cannot. They need to be calibrated to do this and, once calibrated, they can aid inter-ESM comparisons and act as ESM extrapolation tools to reflect and combine knowledge from ESMs and many other lines of evidence.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The emulators don’t (and don’t attempt to) capture the full, noisy temperature record including interannual variability.  Think of them as emulating the underlying forced response of temperature without the obscuring effects of noise.&lt;/p&gt;&#xA;&lt;p&gt;The difference between emulated values +1.14 °C and +1.29 °C is a mixture of several things: the 1750 versus 1850-1900 baselines (about 0.1 °C), the non-anthropogenic forcings (about -0.02 °C), and using end points rather than end periods (about 0.2 °C).  Note that just looking at the end points is normally not recommended in observations and ESMs because a lot of the difference will be internal variability, but that’s not really a problem in these smooth emulations.  You just have to be careful what you do with them, i.e., what other values you’re comparing them to.&lt;/p&gt;&#xA;&lt;p&gt;So, the bottom line is that the best estimate of the warming that has been expressed by the system to date is +1.09 [0.95 to 1.20] °C.  From the AR6 SPM headline statements (my emphasis):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A.1.2 Each of the last four decades has been successively warmer than any decade that preceded it since 1850. Global surface temperature8 in the first two decades of the 21st century (2001-2020) was 0.99 [0.84-1.10] °C higher than 1850-1900. &lt;strong&gt;Global surface temperature was 1.09 [0.95 to 1.20] °C higher in 2011–2020 than 1850–1900&lt;/strong&gt;, with larger increases over land (1.59 [1.34 to 1.83] °C) than over the ocean (0.88 [0.68 to 1.01] °C). The estimated increase in global surface temperature since AR5 is principally due to further warming since 2003–2012 (+0.19 [0.16 to 0.22] °C). Additionally, methodological advances and new datasets contributed approximately 0.1ºC to the updated estimate of warming in AR6.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="106" LastActivityDate="2021-12-18T15:11:33.120" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23328" PostTypeId="1" CreationDate="2021-12-19T07:59:45.357" Score="4" ViewCount="39" Body="&lt;p&gt;One of the means of atmospheric escape is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydrodynamic_escape&quot; rel=&quot;nofollow noreferrer&quot;&gt;hydrodynamic escape&lt;/a&gt;. &lt;br&gt;&#xA;I read someplace that this doesn't cause a change in the isotopic ratio of elements in the atmosphere. But if you heat a group of molecules with a certain amount of thermal energy, the velocities they acquire will be inversely related to their masses, and one could say that eventually, more lighter isotopes will acquire the escape velocity than heavier ones and the heavier isotopes would remain.&lt;/p&gt;&#xA;" OwnerUserId="22530" LastActivityDate="2021-12-19T07:59:45.357" Title="Why does hydrodynamic escape not change isotopic ratio of elements in the atmosphere?" Tags="|atmosphere|" AnswerCount="0" CommentCount="4" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23329" PostTypeId="1" AcceptedAnswerId="23422" CreationDate="2021-12-19T13:44:03.693" Score="8" ViewCount="170" Body="&lt;p&gt;The Cumbre Vieja volcano of La Palma Island, Spain, started to erupt 3 months ago.&lt;/p&gt;&#xA;&lt;p&gt;This week, the volcano stopped emitting lava and there remains only degassing processes. According to &lt;a href=&quot;https://www.mundodeportivo.com/actualidad/20211218/1001727267/cuenta-atras-confirmar-agotamiento-volcan-cumbre-vieja-la-palma-erupcion-final-act-pau.html&quot; rel=&quot;noreferrer&quot;&gt;this news story&lt;/a&gt;, the Spanish National Geographic Institute (IGN) plans to declare the end of the eruption on 25th December if no more activity occurs.&lt;/p&gt;&#xA;&lt;p&gt;That make me wonder: what determines the end of a volcanic eruption and how can it be predicted?&lt;/p&gt;&#xA;" OwnerDisplayName="user20559" LastEditorUserId="6298" LastEditDate="2021-12-19T18:10:03.437" LastActivityDate="2023-10-06T12:34:46.837" Title="What determines when the end of a volcanic eruption will happen?" Tags="|geology|volcanology|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23330" PostTypeId="2" ParentId="23326" CreationDate="2021-12-19T15:21:38.510" Score="3" Body="&lt;p&gt;Not really... there's some problems with your hypothesis.&lt;/p&gt;&#xA;&lt;p&gt;First off, it depends on what you mean by variability.... if you mean the difference between high and low temperature each day, which is what your graph shows, that is indeed greater in the summer most places (exceptions are out there, &lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_of_Mumbai&quot; rel=&quot;nofollow noreferrer&quot;&gt;check out a monsoonal place like India&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;Whereas variation can also mean the range of how hot or cold each day can attain, which is often greater in the winter (see how tall the line or red areas are in the graph below for London):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cb0PQ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cb0PQ.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;(Source: &lt;a href=&quot;https://climatecharts.net&quot; rel=&quot;nofollow noreferrer&quot;&gt;ClimateCharts.net&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;So each day typically has bigger movement in the summer, while the winter tends to have wider swings year-to-year and often week-to-week (depending on when and where fronts and storms go)&lt;/p&gt;&#xA;&lt;p&gt;But focusing on the actual diurnal difference, which does indeed tend to be greater in the summer... there are problems with some of your thoughts on moisture:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Clouds are evidence that there's quite reasonable moisture in the air... they form when the air moving to that level is &amp;quot;full&amp;quot; of moisture.  They don't rob the air of moisture, they're evidence it has &amp;quot;too much&amp;quot;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;And indeed there is more actual water vapor in the air during the summer in the UK, as measured by the dew point temperature:&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/V8Pdj.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/V8Pdj.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;(Source for values: &lt;a href=&quot;https://www.timeanddate.com/weather/uk/london/climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;TimeAndDate.com&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Water vapor does absorb some sunlight (more than most tropospheric gases)... but is not the primary way the Earth is heated:&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wjxN2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wjxN2.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;.&lt;br /&gt;&#xA;(Source: &lt;a href=&quot;https://gpm.nasa.gov/education/lesson-plans/global-energy-budget&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA education site&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;The ground absorbs most solar energy, and then heats the air in contact with it.  So  water vapor absorbing sunlight isn't a big deal to the weather.  It is much more important as a greenhouse gas, redirecting the ground's heat radiation back downward, both day and night.&lt;/p&gt;&#xA;&lt;p&gt;Also, clouds have a bigger impact on sunlight's energy than water vapor... because they reflect sunlight greatly (something verified by being in the sun when a cloud blocks it!)&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;It also can be cloudier in some places during the winter... as shown by this graph for the UK (also true for &lt;a href=&quot;https://weatherspark.com/y/105125/Average-Weather-in-Tehran-Iran-Year-Round#Sections-Clouds&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iran&lt;/a&gt; and &lt;a href=&quot;https://weatherspark.com/y/77807/Average-Weather-in-Prague-Czechia-Year-Round#Sections-Clouds&quot; rel=&quot;nofollow noreferrer&quot;&gt;Czechia&lt;/a&gt;):&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TTk5b.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TTk5b.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;(Source: &lt;a href=&quot;https://weatherspark.com/y/45062/Average-Weather-in-London-United-Kingdom-Year-Round&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weather Spark&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;Fog and stratus are clouds just as much as any others.  Now there tends to be more bubbly cumulus in the summer, more deep convection rising through the atmosphere.  But again, this isn't robbing the atmosphere of water vapor, it's an indication of a fair amount.&lt;/p&gt;&#xA;&lt;p&gt;So why is there more diurnal temperature movement during the summer?&lt;/p&gt;&#xA;&lt;p&gt;I'd suggest it's because there's a larger diurnal heating difference... in other words the sunlight is &amp;quot;hotter&amp;quot; in the summer (due to a more direct angle), and lasts longer.  Then most places still cool back down to nearer the dew point at night.  The extra moisture in the summer if anything dampens the diurnal range in summer (see comments about the factors).&lt;/p&gt;&#xA;&lt;p&gt;Whereas thick persistent clouds in places like London during the winter particularly tend to limit the diurnal range by cooling the daytime and warming the nighttime.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2021-12-19T18:11:31.773" LastActivityDate="2021-12-19T18:11:31.773" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23331" PostTypeId="1" CreationDate="2021-12-19T22:07:49.353" Score="1" ViewCount="112" Body="&lt;p&gt;I am looking for a meteorological measure (formula) of something which combines 2 or more of the following:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;temperature,&#xA;humidity,&#xA;cloud,&#xA;wind,&#xA;precipitation,&#xA;UV&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I have searched, and for example, found the heat-index which combines temperature and humidity, but unfortunately the heat index only has a meaning when the temperature is high, I would be needing a measure which would always &amp;quot;make sense&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;(Background information: I want to set up a mathematical model where some climate information is also included as a side measure and therefore want to &amp;quot;merge&amp;quot; the available time series to a new measure and have more information as input, since otherwise I could always only include a single information.&lt;/p&gt;&#xA;&lt;p&gt;Further background information: Would like to measure the effect of those variables (single variables, or better yet, combination of some of  those) on the time-varying infection rates of COVID infections, the reason those were chosen is because in papers surrounding the topic &amp;quot;meterological factors&amp;quot; and &amp;quot;Covid infections&amp;quot; those were chosen most often)&lt;/p&gt;&#xA;" OwnerUserId="26082" LastEditorUserId="26082" LastEditDate="2021-12-19T23:30:40.170" LastActivityDate="2021-12-24T02:14:04.493" Title="Meterological measures -formula containing temperature, humidity, cloud, wind" Tags="|temperature|measurements|humidity|data-analysis|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="23332" PostTypeId="1" CreationDate="2021-12-20T15:06:25.147" Score="4" ViewCount="262" Body="&lt;p&gt;I live in the Los Angeles area, at sea level. Nearby we have tall mountains where I like to go hiking. I've noticed something strange about the NOAA forecasts, which is that the forecasts in the mountains seem to predict day-night temperature differences that appear implausibly small. Example:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://forecast.weather.gov/MapClick.php?zoneid=CAZ554&amp;amp;zflg=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA forecast for where I live, at sea level&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://forecast.weather.gov/MapClick.php?lon=-117.63404846191406&amp;amp;lat=34.30116926354604&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA forecast for the high elevation area (9000-10000') surrounding a nearby summit&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;These are live, so here are a couple of static screenshots for today and tonight:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SRmFm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SRmFm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BRYge.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BRYge.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The day-night difference is predicted to be about 20 degrees at sea level, but only 8 degrees on the mountain, at about 10,000'. This is a pattern that I've seen repeatedly in the forecasts, not just when the weather is changing or something. For the sea-level temps, I'm able to verify with a thermometer that the forecast is just about right for this morning, and in general the daytime temps at my house are about right, i.e., I believe the 20-degree difference at sea level based on empirical data.&lt;/p&gt;&#xA;&lt;p&gt;The tiny 8-degree difference for the mountains just seems impossible. I don't bring a thermometer with me when I hike, and I don't think there is any actual weather station on top of any of our local mountains, but for instance when I visited this mountain last Friday, it seemed obvious to me that temperatures were increasing rapidly as the day went on.&lt;/p&gt;&#xA;&lt;p&gt;Admittedly I don't have hard data for the temperatures in the mountains. Am I just wrong? Is there some actual physical reason that diurnal differences in the mountains would be so small compared to the ones at sea level? Or is there some bias in the way NOAA's software works, perhaps because they have ground station data at sea level, but not at high elevations?&lt;/p&gt;&#xA;" OwnerUserId="26085" LastEditorDisplayName="user20559" LastEditDate="2021-12-22T09:43:01.167" LastActivityDate="2021-12-22T09:43:01.167" Title="Is there really less diurnal temperature variation in the mountains than at sea level?" Tags="|atmosphere|temperature|mountains|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23333" PostTypeId="2" ParentId="23322" CreationDate="2021-12-20T16:50:32.917" Score="1" Body="&lt;p&gt;If you need to pan-sharpen Landsat imagery, there is a surprisingly large amount of information accessible simply by completing an internet search.  Here is a source from the &lt;a href=&quot;https://earthobservatory.nasa.gov/blogs/earthmatters/2017/06/13/how-to-pan-sharpen-landsat-imagery/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA Earth Observatory&lt;/a&gt; regarding exactly the question about how to pan-sharpen Landsat imagery, specifically Landsat 7 and 8.  They make specific comments about band sensitivities and differences between the sensors on Landsat 7 and 8.  Perhaps the provided source is a jumping off place to begin your work.&lt;/p&gt;&#xA;" OwnerUserId="26086" LastActivityDate="2021-12-20T16:50:32.917" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23334" PostTypeId="2" ParentId="4577" CreationDate="2021-12-21T06:54:42.023" Score="-3" Body="&lt;p&gt;The answer is simple:&#xA;The Earth came out of the Sun as a molten ball of magma.  It took an age to cool and eventually developed a crust as the magma cooled down. So the first &amp;quot;rocks&amp;quot; on Earth must have been &amp;quot;igneous&amp;quot; (developed from a firey or molten state). In Barberton South Africa, the Barberton Greenstone Belt (BGB) comprises a basal lava-rich unit (Onverwacht Group) with Komatiite lavas (primitive, soda-rich, high temperature), followed by the Fig Tree and Moodies (mainly sedimentary and volcanic) groups.&#xA;The question is &amp;quot;What were the komatiite lavas extruded out onto? Today we see a &amp;quot;basement&amp;quot; of granite-type rocks that appear intrusive, and therefore &amp;quot;younger&amp;quot;. This was probably due to remobilization and/or epirogenesis (uplifting of lighter granitic rocks into denser more mafic (Mg, Fe-rich) lavas). Nevertheless, it is more logical to propose that these early lavas would have been extruded onto a solid surface. The very early earth comprised elements from H to Fe only, and Fe (iron) naturally accumulated in the denser core, leaving the classic granite rocks (H, N, O, Al, Si, Na, K etc.) to form the first crust.&#xA;Geologists speak scantly about the Hadean Era as it was essentially devoid of solid rock. That only came about in the Archaean when rocks started to form.&#xA;Rod Tucker (BSc(Eng), MSc, FGSSA, FSAIMM)&lt;/p&gt;&#xA;" OwnerUserId="26087" LastActivityDate="2021-12-21T06:54:42.023" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23335" PostTypeId="2" ParentId="23332" CreationDate="2021-12-21T14:13:55.970" Score="2" Body="&lt;p&gt;This might has more to do with your proximity to the ocean than it does with the elevation. The ocean and all larger bodies of water act as insulators for their locales. During the day, when solar heating creates temperature differences on the landscape, little pockets of wind pop up and bring the ocean regulated air on-land. This is called the marine layer, and it's the reason for increased instances of fog and cooler temperatures in summer along the coast while areas inland bake. In late fall and winter, the marine layer acts oppositely and warms areas along the coast. Water has higher specific heat than the land or air and holds onto its temperature longer, creating a warming insulator during the early cool months. The effect is mostly negated at night as winds calm and the land radiates off its heat more effectively than the ocean, which brings the temperature down quicker.&lt;/p&gt;&#xA;&lt;p&gt;Higher up in the mountains, the daily temperature changes are dictated by the air aloft. While on this particular day, the diurnal range was somewhat small, this range can vary wildly depending on the day and particular atmospheric setup. The reason for this volatility is because higher up in the atmosphere there isn't as much terrain to influence the temperature of the air so sharper fronts (be they cold or warm) are more common. Another thing to consider is how the daily temperature change is influenced by the fact that rising air cools naturally and sinking air warms naturally. So if you're on the western side of the mountains, air is more than likely naturally cooling which could be offsetting heating from the sun.&lt;/p&gt;&#xA;&lt;p&gt;These are mostly theories taking into account atmospheric physics, but with some data a better theory could be drawn.&lt;/p&gt;&#xA;" OwnerUserId="13660" LastEditorUserId="13660" LastEditDate="2021-12-21T19:05:27.073" LastActivityDate="2021-12-21T19:05:27.073" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23337" PostTypeId="2" ParentId="18953" CreationDate="2021-12-22T17:53:35.497" Score="7" Body="&lt;p&gt;This is actually hinted at in the typical Trenberth energy budget diagram for the Earth:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XSsWy.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XSsWy.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The &lt;span class=&quot;math-container&quot;&gt;$86.4\mathrm{\frac{W}{\,m^2}}$&lt;/span&gt; is that energy movement up into the atmosphere from vaporization.  The &lt;span class=&quot;math-container&quot;&gt;$340.3\mathrm{\frac{W}{\,m^2}}$&lt;/span&gt; is the overall greenhouse effect.&lt;/p&gt;&#xA;&lt;p&gt;The very heavy majority of that natural greenhouse effect &lt;a href=&quot;https://skepticalscience.com/water-vapor-greenhouse-gas.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;is water vapor&lt;/a&gt;.  The water cycle indicates that on average that water vapor stays in the atmosphere for two weeks (&lt;a href=&quot;https://hess.copernicus.org/articles/21/779/2017/hess-21-779-2017.html#:%7E:text=Based%20on%20state-of-the-art%20data%2C%20we,atmosphere%20of%208%E2%80%9310%20days&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; now suggests 8-9 days).  So from those details, that means we can consider a water vapor's greenhouse return to be about four times its phase change energy moved.  And so a quarter of the residency time works out to a rough estimate that it takes about 2-4 days for the average water molecule to send as much energy back to the Earth as it brought up from surface to the atmosphere by its absorption and eventual condensation/deposition.&lt;/p&gt;&#xA;&lt;p&gt;I can imagine your friend may not feel comfortable with just using this figure to consider the estimate, so perhaps lets try an alternate way of tunneling down to where these numbers come from....&lt;br /&gt;&#xA;For steady water vapor levels in the atmosphere, the only major way in the end that moisture transfers energy from surface to atmosphere is by its resultant precipitation (other water transitions tend to have no net change on moisture, and don't shift net energy from the ground... water that evaporates and then recondenses at the ground has no net energy change, likewise water vapor that becomes a cloud, then reevaporates at that level has no net energy change over that process).&lt;/p&gt;&#xA;&lt;p&gt;The average daily precipitation on Earth is &lt;a href=&quot;https://www.smithsonianmag.com/arts-culture/what-is-the-daily-rainfall-on-earth-and-more-questions-from-our-readers-37945925/&quot; rel=&quot;nofollow noreferrer&quot;&gt;around 2 mm per area&lt;/a&gt;.  The energy for evaporation is &lt;a href=&quot;https://www.engineeringtoolbox.com/fluids-evaporation-latent-heat-d_147.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;2256 kJ/kg water&lt;/a&gt;.  So for a square meter, that's&#xA;&lt;span class=&quot;math-container&quot;&gt;$$0.2 \frac{\,\mathrm{cm}}{\,\mathrm{day}} \cdot 1\,\mathrm{m^2} \cdot \left(\frac{1\,\mathrm{g}}{\,\mathrm{cm^3}}\right) \cdot 2256 \frac{\mathrm{J}}{\mathrm{g}} \cdot \left(\frac{100\,\mathrm{cm}}{1\,\mathrm{m}}\right)^2 = 45120 \frac{\mathrm{J}}{\mathrm{m^2}}\;\mathrm{per}\;\mathrm{day}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;(the third term is the density of water of &lt;span class=&quot;math-container&quot;&gt;$\frac{1\,\mathrm{g}}{\,\mathrm{cm^3}}$&lt;/span&gt; and the fifth term matches units)&lt;/p&gt;&#xA;&lt;p&gt;Which, converting to per second to get in Watts (multiply by &lt;span class=&quot;math-container&quot;&gt;$\mathrm{\frac{1\,day}{86400\,sec}}$&lt;/span&gt;), that's about &lt;span class=&quot;math-container&quot;&gt;$.5\mathrm{\frac{W}{\,m^2}}$&lt;/span&gt;, which comes out to be on roughly the same scale of value as the figure's latent heat value.&lt;/p&gt;&#xA;&lt;p&gt;How long does it take to achieve that in greenhouse reradiation by that particular water vapor?  In a sense it's not easy to calculate the energy directly by each molecule... we know the radiative properties of water, what &lt;a href=&quot;https://en.wikipedia.org/wiki/Water_vapor_windows&quot; rel=&quot;nofollow noreferrer&quot;&gt;wavelengths water reflects/absorbs/radiates more at&lt;/a&gt;, but it's a cumulative distribution, each molecule affected by its location and interaction with the others that determines the overall amount.  We can look how the greenhouse effect &lt;a href=&quot;https://atmos.washington.edu/academics/classes/2001Q4/211/notes_greenhouse.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;roughly doubles the energy we receive in a day, meaning half of all surface energy is from previous surface radiation being returned back&lt;/a&gt;... which works out to be that &lt;span class=&quot;math-container&quot;&gt;$340.3\mathrm{\frac{W}{\,m^2}}$&lt;/span&gt; of greenhouse return).  But either way, it all leads back to residence time meaning it's that same ratio that was given from the figure, 86.4/340.3, and so the same time.  It may really help to think of it not so much as how long it stays and how much that water molecule contributes while it is in the atmosphere, but instead about the whole water cycle process being what &lt;em&gt;maintains&lt;/em&gt; the amount of water vapor in the atmosphere to allow for that amount of continued greenhouse return, and so it's just one continuous amount versus the other.  But if you really do want to think of it as the time for water vapor to generate its greenhouse effect matching its latent heat transfer, it looks like it must be &lt;strong&gt;on the order of about 3 days&lt;/strong&gt;, or around a quarter of its time in the atmosphere, to result in the energy amounts we see.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-01-02T14:38:05.100" LastActivityDate="2022-01-02T14:38:05.100" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23338" PostTypeId="2" ParentId="23331" CreationDate="2021-12-24T02:14:04.493" Score="3" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Wet-bulb_globe_temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;wet bulb globe temperature&lt;/a&gt; (WBGT) combines 4 or 5 of your variables, while the wet bulb temperature (T&lt;sub&gt;w&lt;/sub&gt;, or equivalently the &lt;a href=&quot;https://en.wikipedia.org/wiki/Heat_index&quot; rel=&quot;nofollow noreferrer&quot;&gt;heat index&lt;/a&gt;, HI) combines only temperature and humidity. This &lt;a href=&quot;https://www.weather.gov/ict/WBGT&quot; rel=&quot;nofollow noreferrer&quot;&gt;chart from the National Weather Service&lt;/a&gt; compares what goes into these measures:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/d5orU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/d5orU.png&quot; alt=&quot;WBGT vs heat index comparison&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Based on your further background information, it could be worth running the model for both WBGT and T&lt;sub&gt;w&lt;/sub&gt;, and see which works better.&lt;/p&gt;&#xA;&lt;p&gt;For COVID infection rates, I suspect that the comfort level of outdoor dining is important. That may be captured best by T&lt;sub&gt;w&lt;/sub&gt; (or HI), because it neglects wind and sunlight. In a dining situation, people can deal with these factors by modifying their immediate surroundings (with shade, lamps, fans, or screens), so neglecting wind and sunlight may be appropriate.&lt;/p&gt;&#xA;&lt;p&gt;WBGT is touted as a better indicator of outdoor safety for more intense exercise or labor, but in those cases, people may not be within 6 feet of each other for long continuous intervals. So WBGT may be a better predictor of activities that don't affect COVID infection rates as much.&lt;/p&gt;&#xA;" OwnerUserId="26100" LastActivityDate="2021-12-24T02:14:04.493" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23340" PostTypeId="2" ParentId="23127" CreationDate="2021-12-25T14:39:45.113" Score="2" Body="&lt;p&gt;CO&lt;sub&gt;2&lt;/sub&gt; is not a factor.&lt;/p&gt;&#xA;&lt;p&gt;Nutrition is the leading factor for height in human, genetics being the second, you can even correlate local nutrition with average height across time and location for human populations based on nutrition. We even know what receptors are responsible. Nutrition development and the industrial revolution went hand and hand in a few countries, so you can see correlation in those populations but not others.&lt;/p&gt;&#xA;&lt;p&gt;As for dinosaurs CO&lt;sub&gt;2&lt;/sub&gt; levels were both higher and lower during the time of large dinosaurs, so there is no reason to believe it is a factor. There are several things contributing to the large size of dinosaurs, most of them physiological. Keep in mind the &lt;a href=&quot;https://www.nationalgeographic.org/media/big-blue-wbt/&quot; rel=&quot;nofollow noreferrer&quot;&gt;largest living animal in history&lt;/a&gt; is alive today and it habitually holds its breath.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Bibliography:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.cambridge.org/core/journals/journal-of-biosocial-science/article/abs/determinants-of-variation-in-adult-body-height/8C3908480AD1B24036A01CE052DE3E03&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.cambridge.org/core/journals/journal-of-biosocial-science/article/abs/determinants-of-variation-in-adult-body-height/8C3908480AD1B24036A01CE052DE3E03&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/s41586-021-04088-9.epdf?sharing_token=NmzYDrN3x9C_d6nbFjJH9tRgN0jAjWel9jnR3ZoTv0OCY5eYLa4RUrBjyz-_gxxQ2SzjZ3VMtCKTslN6fKy3owJQ4T4TFYV00ZObOwRID1Et-Om3DIoggbt-AxO3SpIc7McKjG2Kz0mfiL6GCDz7ZN4vjKyNd7AKUfJ64DIi7QczPvp7kDUpRzc3JQQaIAwHsTG310UEH-3pFOdbtUnQ0g%3D%3D&amp;amp;tracking_referrer=www.bbc.com&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/s41586-021-04088-9.epdf?sharing_token=NmzYDrN3x9C_d6nbFjJH9tRgN0jAjWel9jnR3ZoTv0OCY5eYLa4RUrBjyz-_gxxQ2SzjZ3VMtCKTslN6fKy3owJQ4T4TFYV00ZObOwRID1Et-Om3DIoggbt-AxO3SpIc7McKjG2Kz0mfiL6GCDz7ZN4vjKyNd7AKUfJ64DIi7QczPvp7kDUpRzc3JQQaIAwHsTG310UEH-3pFOdbtUnQ0g%3D%3D&amp;amp;tracking_referrer=www.bbc.com&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="2470" LastEditDate="2021-12-28T16:56:06.583" LastActivityDate="2021-12-28T16:56:06.583" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23341" PostTypeId="1" CreationDate="2021-12-26T13:37:21.467" Score="1" ViewCount="786" Body="&lt;p&gt;Which is more susceptible to landslide based on lithology compared to one another?&#xA;Granite, Conglomerate, Sandstone, Mudstone&lt;/p&gt;&#xA;&lt;p&gt;I've been tasked to create a hazard map and was given a Geologic Map, Rainfall Map and Topographic Map. This question mainly pertains to the Geologic Map. How do these 4 different lithologies compare their proneness to landslide against one another?&lt;/p&gt;&#xA;&lt;p&gt;I have done some searching and still am not sure of which is more prone against the other.&lt;/p&gt;&#xA;&lt;p&gt;This is an excerpt from here: &lt;a href=&quot;https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=2632&amp;amp;context=icwdm_usdanwrc&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=2632&amp;amp;context=icwdm_usdanwrc&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Granite (an igneous rock) is one type of parent material that, when weathered, results in relatively high slope instability, as found on landslides in Korea (Wakatsuki et aI., 2005) and Nepal (Ibetsberger, 1996). The instability of granite rocks probably results from relatively&#xA;slow weathering, which produces shallow soils with low water storage and high permeability (Sidle &amp;amp; Ochiai, 2006).&lt;/p&gt;&#xA;&lt;p&gt;Weak sedimentary rocks, such as mudstone and shale, are also highly susceptible to landslides&#xA;(Pearce &amp;amp; O'Loughlin, 1985; Chigira &amp;amp; Oyama, 1999). The presence of particular compounds and oxidation in sandstone (another sedimentary rock) determines if it is weakened and therefore more susceptible to landslides, or if it is strengthened by cementation by iron oxide or&#xA;hydroxide (Chigira &amp;amp; Oyama, 1999).&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;My guess,for now, is: Mudstone &amp;gt; Sandstone &amp;gt; Granite &amp;gt; Conglomerate&lt;/p&gt;&#xA;&lt;p&gt;I have not found any source for conglomerate though. I'm mostly just basing this off of the rock's resistance to weathering.&lt;/p&gt;&#xA;" OwnerUserId="26107" LastEditorUserId="22648" LastEditDate="2021-12-27T17:24:37.800" LastActivityDate="2021-12-27T17:24:37.800" Title="Igneous and Sedimentary Rocks' Susceptibility to landslide" Tags="|geology|earthquakes|rocks|sedimentology|mountains|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23342" PostTypeId="1" CreationDate="2021-12-26T20:55:55.330" Score="4" ViewCount="79" Body="&lt;p&gt;I just started researching iron fertilization, which is the induction of carbon sinks in the atmosphere through depositing iron in large areas, specifically the ocean. Why do most of the studies regarding carbon sinks revolve around iron, and not other various nutrients like nitrogen and phosphorous that exist?&lt;/p&gt;&#xA;&lt;p&gt;I know that iron is an important mineral for photosynthesis, but so is nitrogen. Is there any specific properties about iron that makes it more important in the process of phytoplankton growth?&lt;/p&gt;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;" OwnerUserId="26108" LastEditorUserId="6467" LastEditDate="2021-12-27T01:34:46.143" LastActivityDate="2021-12-27T23:36:47.813" Title="Why is iron an essential part of iron fertilization and carbon sink?" Tags="|climate|geoengineering|plant|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23343" PostTypeId="1" CreationDate="2021-12-27T00:33:14.967" Score="2" ViewCount="156" Body="&lt;p&gt;&lt;em&gt;Geopolitics and costs aside&lt;/em&gt;, would damming the Baltic Ocean and the White Sea be enough to provide a renewable supply of water to water stressed Central Asia? Central Asia because its closest and has the Caspian Sea and Aral Sea which naturally provides a storage mechanism for the water.&lt;/p&gt;&#xA;&lt;p&gt;I was thinking that if we dam the Baltic at Denmark, then over time the fresh water inflow in the north by means of rivers and freezing in winter (of 660 km&lt;sup&gt;3&lt;/sup&gt; annually) will completely replace the salt water in the ocean within a max time of 50 years (giving a little leeway for mishaps in between). Repeat the same for the White. This water can then be pumped to Aral or Caspian Sea by connecting it to the Volga river in Russia which drains into the Caspian. And then pump it into the Aral for more storage if necessary.&lt;/p&gt;&#xA;&lt;p&gt;1 Billion people consume 500 km&lt;sup&gt;3&lt;/sup&gt; of water. Currently, the population of Central Asia is approximately 70 million. Assuming we the central Asian population will peak at 1 billion, then we have more than enough water. However this doesn't take into account Baltic ocean states water uses as they too will want some. The White Sea is also another source in the background using the same strategy of damming at the straits narrow point. So, will it work?&lt;/p&gt;&#xA;" OwnerUserId="26109" LastEditorUserId="2470" LastEditDate="2021-12-30T10:51:44.930" LastActivityDate="2022-01-07T07:29:44.663" Title="Solutions to the global water shortages by damming the Baltic Ocean and the White Sea" Tags="|oceanography|water|geoengineering|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23344" PostTypeId="1" CreationDate="2021-12-27T10:05:48.217" Score="5" ViewCount="89" Body="&lt;p&gt;High pressure systems are normally correlated with stable atmospheric conditions with little to no cloud cover, but due to this minimal cloud cover, doesn't that open up the ocean / ground moisture to evaporate to then later condensate to form clouds?&lt;/p&gt;&#xA;&lt;p&gt;I understand there are other forms of cloud formation like subsidence or frontal uplift, but some days here in Perth are very still and there hasn't been any fronts recently. For example during today (27/12/2021), it has been very still yet the heat has reached 40°C. For the previous two days there has also been temperatures reaching up to 45°C for prolonged periods of time with clear skies. I haven't felt much wind or any down drafts within my vicinity.&lt;/p&gt;&#xA;&lt;p&gt;Today, there has been altostratus, altocumulus and cirrus clouds. Most of the clouds are isolated but some have formed extensive 'clumps' of cloud coverage with other clouds. So despite the high pressure system is it possible for there to be a decent amount of cloud generation? Can the ocean evaporate despite there being descending air? &lt;a href=&quot;https://i.stack.imgur.com/xmNT0.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xmNT0.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26112" LastEditorUserId="26112" LastEditDate="2021-12-27T10:13:58.523" LastActivityDate="2022-01-18T14:16:32.347" Title="Formation of Clouds in High Pressure Systems (Western Australia - Perth)" Tags="|meteorology|clouds|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23345" PostTypeId="2" ParentId="23342" CreationDate="2021-12-27T23:36:47.813" Score="2" Body="&lt;p&gt;That's largely because iron is scarce in seawater. It is what is known as a limiting factor -- certain physiological processes can't occur in the absence of iron, so even if nutrients such as nitrogen and phosphorous are plentiful many organisms cannot metabolize them.&lt;/p&gt;&#xA;&lt;p&gt;Here's one popular-science article on this theme: &lt;a href=&quot;https://www.smithsonianmag.com/science-nature/complicated-role-iron-ocean-health-and-climate-change-180973893/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Complicated Role of Iron in Ocean Health and Climate Change&lt;/a&gt;&#xA;And a 2017 scientific paper in &lt;em&gt;Nature&lt;/em&gt; that explores a particular case: &lt;a href=&quot;https://www.nature.com/articles/nature24063&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nutrient co-limitation at the boundary of an oceanic gyre&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Our results suggest that nitrogen–iron co-limitation is pervasive in&#xA;the ocean, with other micronutrients also approaching co-deficiency.&#xA;Such multi-nutrient limitations potentially increase phytoplankton&#xA;community diversity.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2021-12-27T23:36:47.813" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23346" PostTypeId="1" CreationDate="2021-12-28T00:07:07.010" Score="2" ViewCount="85" Body="&lt;p&gt;I am trying to make a fictional world, but I want to be as realistic as humanly possible with the winds and climate. So my question is, knowing various parametres, how exactly can I make out what paths these would follow and what their temperatures and humidity should be? At least a decent estimate.&lt;/p&gt;&#xA;&lt;p&gt;The atmosphere is Earth-like (basically identical in composition), and as far as I am now, it is the same size with same distance to the sun, and same rotational velocity and such. Would this just make it identical to Earth in winds? If it had a different size or rotational velocity, how exactly would this effect the winds?&lt;/p&gt;&#xA;" OwnerUserId="26118" LastActivityDate="2021-12-30T05:02:21.110" Title="How exactly can one make out the direction of and temperature of winds" Tags="|meteorology|planetary-science|climate-models|" AnswerCount="1" CommentCount="8" ClosedDate="2022-01-16T09:49:47.297" ContentLicense="CC BY-SA 4.0" />
  <row Id="23347" PostTypeId="1" AcceptedAnswerId="23348" CreationDate="2021-12-28T07:52:12.010" Score="5" ViewCount="240" Body="&lt;p&gt;For what I know so far about this phenomenon, it's a super cold mass of dry air accumulating in Siberia and Far East of Russia from September to April.&lt;/p&gt;&#xA;&lt;p&gt;I want to know how it accumulates cold air in the first place and how likely it would send cold air down to places as far south as Southeast Asia.&lt;/p&gt;&#xA;" OwnerUserId="25046" LastEditorUserId="2470" LastEditDate="2021-12-28T09:33:52.527" LastActivityDate="2021-12-29T15:12:29.993" Title="How does Siberian High develop?" Tags="|meteorology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23348" PostTypeId="2" ParentId="23347" CreationDate="2021-12-29T14:44:36.347" Score="5" Body="&lt;p&gt;The principle is the same as for radiative surface cooling during a long night with clear sky. Just in larger spatial and temporal proportions.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Is it also because of the lack of daylight too ?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Longer nights and little daylight lead to more intensive radiative cooling. Snow cover helps, as while snow reflects visible light well, it is like a radiating black body in the thermal IR region.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Considering that Siberia lies in the eastern region of Russia and because the wind generally blows towards east, it'd get colder the further east you go. Does that add any effect to Siberian High too?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;There is no direct relation. Mostly western winds in Europe are caused by controling Atlantic low near Iceland and the high near Azore islands. Siberia and Central Asia have continental climate with big summer/winter temperature difference, as tempering ocean effect is minimal.&lt;/p&gt;&#xA;&lt;p&gt;The pressure high formed by cold and dense air causes counter-clockwise outward winds around itself.&lt;/p&gt;&#xA;&lt;p&gt;That cold air is stable, as surface is even colder. If it came over warmer surface, it would cause an intense cold front.&lt;/p&gt;&#xA;" OwnerUserId="21346" LastEditorUserId="21346" LastEditDate="2021-12-29T15:12:29.993" LastActivityDate="2021-12-29T15:12:29.993" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23349" PostTypeId="2" ParentId="23346" CreationDate="2021-12-29T19:18:03.433" Score="2" Body="&lt;p&gt;You cannot.&lt;/p&gt;&#xA;&lt;p&gt;There are two different approaches for that. Short term meteorological one and long term climatological one.&lt;/p&gt;&#xA;&lt;p&gt;For the short term, the behaviour of atmosphere can be described by Richardson's differential equations, but the problem is the solution is mathematically instable. Slight inaccuracy and incompleteness of initial and border condition — i.e. input measurement data — leads to divergence of predicted future state.&lt;/p&gt;&#xA;&lt;p&gt;So, for more than 10-14 days in future, any numerical prediction based on current state is lost in noise.&lt;/p&gt;&#xA;&lt;p&gt;The long term climatological approach works with probabilities and long term observed spatial and temporal behaviour patterns. But it mostly focus on expected ranges of average surface temperature and precipitation.&lt;/p&gt;&#xA;&lt;p&gt;Parameters like strength direction and temperature of wind has too high variability for that. Unless it is the case of typical seasonal winds like passats or monzunes.&lt;/p&gt;&#xA;&lt;p&gt;Both meteorological and climatological predictions largely depend on particular land and sea layouts, sea temperature and stream patterns.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Meteorology and climatology search for the answer for the hundred years and you want to get it in the single StackExchange post. Or rather, they already know  the answer - there is no definite nor exact answer - and just try to find good approximations.&lt;/p&gt;&#xA;&lt;p&gt;For particular, regularly observed patterns, you can make quite reliable predictions. If there is observed for some season the wind blows toward this side of mountain range, you can make such a prediction. But you cannot make general predictions for variable patterns, unless short term ones.&lt;/p&gt;&#xA;&lt;p&gt;So, take current short term  meteorological forecasts and long term outlooks and you get the reliable picture how accurate predictions can be made.&lt;/p&gt;&#xA;" OwnerUserId="21346" LastEditorUserId="21346" LastEditDate="2021-12-30T05:02:21.110" LastActivityDate="2021-12-30T05:02:21.110" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23351" PostTypeId="1" CreationDate="2021-12-30T05:24:41.690" Score="6" ViewCount="1592" Body="&lt;p&gt;I have subsurface temperature data for up to 300 m oceanic depth (at varying depth intervals). I want to calculate the ocean heat content for 0-300 m.&lt;/p&gt;&#xA;&lt;p&gt;The formula is:&lt;/p&gt;&#xA;&lt;p&gt;OHC = seawater density * Specific heat capacity * integrating the temperature over this depth.&lt;/p&gt;&#xA;&lt;p&gt;But, the depth is not at the same interval. So I have read that there is a need to use weighted temperature.&#xA;I want to ask two questions.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Why do we have to use weighted temperature?&lt;/li&gt;&#xA;&lt;li&gt;Is there any module or code available to do this? So that it will help me to compute the OHC?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="26131" LastEditorUserId="2470" LastEditDate="2021-12-30T08:24:33.480" LastActivityDate="2022-02-12T01:16:33.557" Title="How to calculate Ocean heat content?" Tags="|climate|oceanography|data-analysis|python|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23352" PostTypeId="2" ParentId="23343" CreationDate="2021-12-30T10:10:12.977" Score="2" Body="&lt;p&gt;If you're only asking &amp;quot;would there be enough water replaced for both the Baltic Sea region and Central Asia&amp;quot;, the answer is simple mathematics.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://helcom.fi/media/publications/BSEP111.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;HELCOM&lt;/a&gt; states the size of the Baltic Sea catchment area to be some 1.74 million sq km (p. 10) and the mean precipitation since the mid-80s to be about 750 mm/a (p. 15).&lt;/p&gt;&#xA;&lt;p&gt;1 740 000 km² × 750 mm = 1.740 × 10&lt;sup&gt;12&lt;/sup&gt; m² × 0.75 m = 1.305 × 10&lt;sup&gt;12&lt;/sup&gt; m³ = 1305 km³ precipitation in the catchment area per year.&lt;/p&gt;&#xA;&lt;p&gt;So yes, theoretically the fresh water &amp;quot;generated&amp;quot; within the Baltic Sea area would be enough to supply the area itself and Central Asia, too, going with the numbers you ballparked. I will omit pointing at the &lt;strong&gt;many&lt;/strong&gt; things you'd have to consider.&lt;/p&gt;&#xA;" OwnerUserId="14194" LastEditorUserId="2470" LastEditDate="2021-12-30T11:07:47.330" LastActivityDate="2021-12-30T11:07:47.330" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23353" PostTypeId="2" ParentId="23351" CreationDate="2021-12-30T11:05:16.430" Score="3" Body="&lt;p&gt;The temperature readings are point samples which can occur at various depths depending on who took the reading, how they were taken &amp;amp; the conditions at the time when they were taken.&lt;/p&gt;&#xA;&lt;p&gt;If modeling heat in ocean water is similar to modeling metal content in rocks it is useful to get the average for a particular band, such as 0-10 m, 10-20 m, etc., by way of example. If a reading occurs at 6 m, a second one at 12 m &amp;amp; a third one at 14 m they have to assigned to the correct band &amp;amp; the readings for 12 m &amp;amp; 14 m, if the band interval is 10-20 m, need to be averaged appropriately &amp;amp; one way to do this is to apply weighted averaging to the data so there is only one value for each band.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2021-12-30T11:05:16.430" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23355" PostTypeId="1" AcceptedAnswerId="23357" CreationDate="2022-01-03T11:20:44.443" Score="3" ViewCount="2251" Body="&lt;p&gt;I am a bit confused about pressure vs temperature effect on relative humidity.&lt;/p&gt;&#xA;&lt;p&gt;I know that air density is decreased with altitude, which means that there is more &amp;quot;space&amp;quot; between air molecules in a volume of air. If so, there is more place for water vapour so relative humidity should decrease.&lt;/p&gt;&#xA;&lt;p&gt;But temperature also decrease with altitude, and lower the temperature is, there is less &amp;quot;space&amp;quot; for water vapour so the relative humidity increases.&lt;/p&gt;&#xA;&lt;p&gt;So I know that with altitude the humidity increases, but why no one talks about the pressure effect on relative humidity? Is it so minor that it's doesn't affect?&lt;/p&gt;&#xA;&lt;p&gt;So what happens to a volume of air which move for example from 0 feet to 18000 feet where the pressure is half of sea level and the temperature is lower? The pressure difference is high so I believe it should affect humidity too...&lt;/p&gt;&#xA;" OwnerUserId="26143" OwnerDisplayName="Meir Tolpin" LastEditorDisplayName="user20559" LastEditDate="2022-01-03T17:06:33.670" LastActivityDate="2022-01-05T17:06:22.317" Title="Pressure vs Temperature effect on humidity" Tags="|meteorology|atmosphere|temperature|humidity|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23356" PostTypeId="2" ParentId="4577" CreationDate="2022-01-03T12:15:58.327" Score="1" Body="&lt;p&gt;The earth condensed from gas into liquid into solid.&lt;/p&gt;&#xA;&lt;p&gt;Rocks are assumed to be solids and not a fluid part of a melt.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Bowen%27s_reaction_series&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bowens Reaction Series&lt;/a&gt; implies that the first rocks on earth would have been &lt;a href=&quot;https://en.wikipedia.org/wiki/Olivine#High-pressure_polymorphs&quot; rel=&quot;nofollow noreferrer&quot;&gt;Olivine Polymorphs&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;MgSiO3-perovskite and MgO (periclase) are likely candidates from &lt;a href=&quot;https://www.nature.com/articles/35079060&quot; rel=&quot;nofollow noreferrer&quot;&gt;observations at the Earths Moho&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;As far as the &amp;quot;rock cycle&amp;quot; goes; these first rocks would be classified as igneous.&lt;/p&gt;&#xA;" OwnerUserId="6463" LastActivityDate="2022-01-03T12:15:58.327" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23357" PostTypeId="2" ParentId="23355" CreationDate="2022-01-03T13:10:30.657" Score="3" Body="&lt;p&gt;Be aware that vapor capacity in &lt;span class=&quot;math-container&quot;&gt;$\pu{g/m^3}$&lt;/span&gt; is property of space and water itself - air is just a spectator here. It grows about exponentially with temperature, typically doubles every &lt;span class=&quot;math-container&quot;&gt;$\pu{10^{\circ}C}$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The given absolute &lt;a href=&quot;https://en.wikipedia.org/wiki/Humidity&quot; rel=&quot;nofollow noreferrer&quot;&gt;humidity&lt;/a&gt; in &lt;span class=&quot;math-container&quot;&gt;$\pu{g/m^3}$&lt;/span&gt; slightly decreases with temperature ( at the same pressure ) due air thermal dilation. The absolute humidity is proportional to pressure, as air expands in low pressure and vapor is spreaded in greater volume ( and vice versa ).&lt;/p&gt;&#xA;&lt;p&gt;The relative humidity is ratio (in percents) of the absolute humidity and of the vapor capacity, the latter dependent only on temperature.&lt;/p&gt;&#xA;&lt;p&gt;When air raises by thermal or forced vertical convection, its relative humidity raises, as its temperature adiabatically drops about &lt;span class=&quot;math-container&quot;&gt;$\pu{1^{\circ}C / 100 m}$&lt;/span&gt; and vapor capacity decreases. This relative humidity raising is slightly slower, compared to the static air cooling, as air expands and its absolute humidity slowly decreases.&lt;/p&gt;&#xA;&lt;p&gt;As result, near surface, if air raises, its dew point decreases at rate about &lt;span class=&quot;math-container&quot;&gt;$\pu{0.18^{\circ}C / 100 m}$&lt;/span&gt;.&lt;/p&gt;&#xA;" OwnerUserId="21346" LastEditorUserId="21346" LastEditDate="2022-01-04T08:02:35.893" LastActivityDate="2022-01-04T08:02:35.893" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23358" PostTypeId="2" ParentId="9488" CreationDate="2022-01-04T02:20:04.710" Score="-1" Body="&lt;p&gt;Hate to break bad news, but we don't know.  As oxygen is one of most abundant elements on earth by mass (not merely crustal), free protons or hydrogen atoms (as electrons are abundant) are more likely to be a limiting factor for water than oxygen by factor of 100:1.  Of course, tracking hydrogen is downright difficult, as it just turns back into water under normal conditions...therefore its a proxy that resists observation.  But one way we gain net hydrogen -- aside from measureable debris infall -- is not from &lt;em&gt;any&lt;/em&gt; chemical means, is from solar and cosmic showers -- neutrons, gamma &amp;amp; muons, protons.  Of those, thermal neutrons are somewhat well absorbed by nitrogen-14, which becomes carbon-14 and emits a proton.  This proton is gonna meet an electron guaranteed, and likely to become water, as vapor or precipitate out.  Of course, jeans escape on the other hand, does the opposite, allows for natural hydrogen escape. Since we do not have any way of tagging this activity, tracking such protons &amp;amp; hydrogen...we can't really say if we are even losing or gaining net water, or just essentially re-venting incoming protons.  All we know, is both opposing processes occur, but we can't say for certain if there is &lt;em&gt;overlap&lt;/em&gt; or not.  2021 published studies cite solar wind as a significant chunk earth's watery origin.&lt;/p&gt;&#xA;" OwnerUserId="26144" LastEditorUserId="26144" LastEditDate="2022-01-04T02:34:07.000" LastActivityDate="2022-01-04T02:34:07.000" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23359" PostTypeId="1" AcceptedAnswerId="23367" CreationDate="2022-01-04T10:44:15.093" Score="4" ViewCount="771" Body="&lt;p&gt;I'm helping my daughter with a science experiment for school to show the effect of CO2 enrichment on plant growth.  We have two small tabletop greenhouses with approximately 10 Liter volume and we're trying to achieve approximately 1500 ppm in one of the greenhouses.  Our current idea is to use carbonated water as a CO2 source.  Basically, from what I've read typical carbonated water will have about 6 grams of dissolved CO2 per liter which translates to 3 liters of CO2 gas, &lt;a href=&quot;https://www.sciencedirect.com/topics/agricultural-and-biological-sciences/carbonation&quot; rel=&quot;nofollow noreferrer&quot;&gt;if I understand correctly&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Carbonation is measured as either ‘volumes’ or grams per litre. One volume means 1 L of CO2 in 1 L of drink. This is equivalent to 1.96 g/L (normally quoted as 2 g/L). A typical carbonated soft drink contains approximately 3–4 volumes (6–8 g/L) CO2.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Assuming the low end of 3 liters CO2 gas per liter soda we get each milliliter of soda contains 0.003 liter CO2.  Ambient air has about 400 ppm CO2 or 0.04%, or about 0.0004 liters CO2 per liter air, so to bring it up to about 1500 ppm I would need to add 0.0011 X 10 or 0.011 liters CO2 to the greenhouse, or about 4ml of carbonated water.&lt;/p&gt;&#xA;&lt;p&gt;The problem is this whole process is very imprecise, and it would be nice if there was a way to measure the CO2 content within 100 ppm with a range of say 0 - 5000 ppm which doesn't cost hundreds of dollars, since this is a 9th grade science project.&lt;/p&gt;&#xA;&lt;p&gt;Any ideas?&lt;/p&gt;&#xA;" OwnerUserId="26145" LastActivityDate="2022-01-06T21:06:13.383" Title="How to measure Air CO2 Cheaply for a School Science Experiment" Tags="|measurements|co2|agriculture|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23360" PostTypeId="2" ParentId="23355" CreationDate="2022-01-04T22:52:37.787" Score="2" Body="&lt;p&gt;The thing is, the density decreasing with height, which is caused by the reduced surrounding pressure, does mean the air is spread out more... but likewise also means the water vapor must take up a larger space for the same amount of molecules too.  And so that density/pressure change basically doesn't mean any &amp;quot;more room&amp;quot; for water vapor (the expanding existing water vapor volume takes it all).&lt;/p&gt;&#xA;&lt;p&gt;...&lt;/p&gt;&#xA;&lt;p&gt;Looking deeper, we often talk about it all loosely in terms of &amp;quot;room&amp;quot;.  But truly temperature decrease isn't directly changing the room (yes there can be a density/volume change, but also a pressure change), but means the molecules are moving slower and so are more likely to condense together.&lt;/p&gt;&#xA;&lt;p&gt;As you lift unsaturated air, the amount of molecules of water vapor and air stay the same.&lt;br /&gt;&#xA;The total and vapor densities decrease by equal ratios due to the reduced surrounding pressure, which also brings a temperature decrease because energy is used to expand to fill the larger volume.  And both of those mean their internal pressures fall by the ideal gas law.&lt;/p&gt;&#xA;&lt;p&gt;But as &lt;a href=&quot;https://earthscience.stackexchange.com/a/23357/6298&quot;&gt;Poutnik indicated&lt;/a&gt;, the saturation vapor pressure (what is often poorly alluded to as the &amp;quot;room&amp;quot; available) is &lt;a href=&quot;https://en.wikipedia.org/wiki/Vapour_pressure_of_water&quot; rel=&quot;nofollow noreferrer&quot;&gt;basically only a (direct) function of temperature in our atmosphere&lt;/a&gt;.  So it decreases as temperature decreases, and isn't significantly affected by any isothermal processes.  And while a lot of variables change in lifting air (the dew point and specific humidity both decrease due to the density drop/parcel expansion... and the vapor pressure drops due to the temperature decrease), the mixing ratio doesn't change, and so the only notable cause for change in relative humidity is the decreasing temperature's impact on saturation vapor pressure (the amount of &amp;quot;room&amp;quot; available until saturation, which isn't so much about room, but freedom).&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-01-05T17:06:22.317" LastActivityDate="2022-01-05T17:06:22.317" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23361" PostTypeId="1" CreationDate="2022-01-05T14:23:06.993" Score="3" ViewCount="110" Body="&lt;p&gt;I have a 2-D latitude-time zonal wind netCDF dataset (such as &lt;a href=&quot;https://drive.google.com/file/d/1MQVvg2qICY5AxVAMrtmW_5aPc9bA_Q-W/view?usp=sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;this small sample from ERA-Interim&lt;/a&gt;) from which I want to find all local maxima of the zonal wind as a function of latitude, for each time step. The output should be a list of latitudes (possibly empty) for each time step.&lt;/p&gt;&#xA;&lt;p&gt;I would prefer to use mostly python, cdo and/or nco, if possible. I can use the derivative function in python xarray and specify the latitude dimension, for example, and then find roots of this new function subject to a condition on the second derivate, but I've not come across a function for finding zeroes/roots of a 2-D array along a specific dimension. Is there a more efficient, preferable way of going about this task?&lt;/p&gt;&#xA;&lt;p&gt;Please let me know if this is not appropriate for the Earth Science Stack Exchange and where I should rather post the question if so.&lt;/p&gt;&#xA;" OwnerUserId="22143" LastActivityDate="2022-01-05T14:23:06.993" Title="Efficient way to find spatial extrema in 2-D space time netcdf field" Tags="|climatology|netcdf|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23362" PostTypeId="1" CreationDate="2022-01-05T20:12:38.730" Score="4" ViewCount="490" Body="&lt;p&gt;Why is the potential temperature, defined as &lt;span class=&quot;math-container&quot;&gt;$\theta = T\Big(\frac{P_0}{P}\Big)^{R/c_p}$&lt;/span&gt;, constant in a well-mixed layer? I understand that the dew point temperature has to be parallel to a line of equal mixing ratio in the T-log P diagram, but I have trouble connecting this to the fact that the temperature sounding is parallel to a dry adiabatic lapse rate (DALR).&#xA;The potential temperature is the temperature an air parcel would have if it were brought dry-adiabatically to 1000 mbar. But since temperature doesn't have to be homogeneously distributed in a well-mixed layer, why would the potential temperature be constant?&lt;/p&gt;&#xA;&lt;p&gt;An example of a well-mixed layer is shown here (the layer that extends from the surface to about 650 hPa):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/9GYlo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9GYlo.png&quot; alt=&quot;T-logP diagram&quot; /&gt;&lt;/a&gt;&#xA;I got the image from &lt;a href=&quot;https://www.cs.ubc.ca/%7Etmm/courses/cpsc533c-06-fall/projects/sancho/proposal/documents/Skew-T-Manual.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this manual&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="22353" LastActivityDate="2022-06-05T02:16:40.403" Title="Potential temperature constant in a well-mixed atmospheric layer?" Tags="|meteorology|atmosphere|temperature|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23363" PostTypeId="2" ParentId="23362" CreationDate="2022-01-05T20:58:21.340" Score="1" Body="&lt;p&gt;The whole idea of well-mixed is that it all has the same properties (as you note the moisture profile, the left line, also follows the mixing ratio, showing it has the same moisture.... winds don't have to be constant, as they are driven by surrounding pressure fields, but will tend to be more similar than in unmixed profiles)&lt;/p&gt;&#xA;&lt;p&gt;Well in terms of temperature, the air is also all of the same quality when well mixed... except with the background that as it rises/falls it always gains/loses the energy of expanding/compressing.  But in near-adiabatic processes, that process is reversible.&lt;/p&gt;&#xA;&lt;p&gt;So an oddball analogy: picture it as a skyscraper which has an elevator with a fee to ride up, based upon the number of floors, but which is returned when you ride back down in the same rate.  And everyone in the building decides to &amp;quot;mix&amp;quot; their monies, so that each has fundamentally the same amount in the end, when they leave I guess.  It'd make it so people on different floors would have different amounts due to the elevator rides they've done, but because that elevator process is just a background, and they all fundamentally have the same amount, as anyone could take the elevator to another floor, and have the same amount as the person there.&lt;/p&gt;&#xA;&lt;p&gt;So a mixed region is like an elevator with a &lt;span class=&quot;math-container&quot;&gt;$9.8\,\mathrm{°C}$&lt;/span&gt; fee per &lt;span class=&quot;math-container&quot;&gt;$\mathrm{km}$&lt;/span&gt; of height.  And even if the mixed region doesn't happen to include 1000 mb, that'd be like if they only mixed monies on floors 15-23 on the skyscraper... we could still reference all back down to the money they'd have when they leave the building.  So it is with potential temperature, we have to reference it to the same level, and we just happen to have defined it as 1000 mb.  But a mixed layer can be over any pressure level range.&lt;/p&gt;&#xA;&lt;p&gt;When temperatures follow those dry adiabat lines it shows that they have the same true base values, accounting for the reversible change from lifting/sinking.&lt;/p&gt;&#xA;&lt;p&gt;So temperature &lt;strong&gt;is&lt;/strong&gt; vertically homogeneously distributed in a well-mixed layer, except the background requirement that it be stratified by the temperature change to get to the different levels each air molecule is at.  Temperature isn't necessarily entirely horizontally homogeneous at the lowest levels in such a mixed atmosphere because of topography, ground cover, etc... but again it will tend to be more similar because vertical mixing suggests decent horizontal motion (mass continuity), and will tend to mix down any increased winds aloft (due to reduced friction) so there will tend to be more motion to mix horizontally near ground level than on more stable days.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2022-01-05T20:58:21.340" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23364" PostTypeId="2" ParentId="23362" CreationDate="2022-01-05T20:59:42.700" Score="1" Body="&lt;p&gt;It is a simple adiabatic scenario.&lt;/p&gt;&#xA;&lt;p&gt;When an air parcel idiabatically raises, its heat exchange with surrounding is zero. Therefore, the decreased internal energy (with the related temperature decrease) of an air parcel is equal to the work done by the parcel during its expansion, and vice versa.&lt;/p&gt;&#xA;&lt;p&gt;This change is reversible.&lt;/p&gt;&#xA;" OwnerUserId="21346" LastActivityDate="2022-01-05T20:59:42.700" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23366" PostTypeId="1" CreationDate="2022-01-06T15:42:50.267" Score="1" ViewCount="57" Body="&lt;p&gt;With very limited background in the physics of air and weather, this question occurred to me for no particular reason. With that in mind, a simplified answer would be much appreciated.&lt;/p&gt;&#xA;&lt;p&gt;This weatherman's account is all that I have to go by: &lt;a href=&quot;https://youtu.be/aiYyCurh_SU&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://youtu.be/aiYyCurh_SU&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Although, it was not clear to me as to why we have converging and diverging air aloft. I have a few other minor questions but I think that which was stated in the Question Header will make things clearer.&lt;/p&gt;&#xA;&lt;p&gt;Thank you for your time.&lt;/p&gt;&#xA;" OwnerUserId="26160" LastActivityDate="2022-01-06T15:42:50.267" Title="In terms of atmospheric pressure, why do pressure systems move and what factors affect the general pressure of an area?" Tags="|meteorology|atmosphere|climate|pressure|air-currents|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23367" PostTypeId="2" ParentId="23359" CreationDate="2022-01-06T21:06:13.383" Score="2" Body="&lt;p&gt;There are a number of simple sensors around for Arduino/Pi setups that will measure CO2 for around $50 - pubs.acs.org/doi/10.1021/acs.jchemed.8b00473 has an example of their use. There are packaged sensors with displays for similar prices on online marketplaces. some considerably cheaper.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2022-01-06T21:06:13.383" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23368" PostTypeId="2" ParentId="23343" CreationDate="2022-01-07T07:29:44.663" Score="2" Body="&lt;p&gt;There is no &amp;quot;Global&amp;quot; water shortage&#xA;Water is a geopolitical issue, the biggest is clean water in 3rd world and any available water in more arid regions. The nations with the biggest water issues&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Middle East: Scarcity issues&lt;/li&gt;&#xA;&lt;li&gt;China: Water Quality&lt;/li&gt;&#xA;&lt;li&gt;India: Both, availability is also a problem...&#xA;small/moderate scale programs to address water issues, India leads the charge...on small village scale water acquisition, sterilization and well recharge.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Nuclear powered desalination offers the biggest grand scale changes for some nations, however technology is not applicable to poorer nations or nations whose Large scale water issues are byproduct of being in interior of continents away from ocean. Even if.... sending water hundreds or thousands of miles to water stressed regions (Often at high altitude regions) is a particularly expensive scenario. However there are some shorter term methods.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=9J1_tuKW7-g&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rainwater harvesting&lt;/a&gt;   An inch of water over an acre of land produces 27,000 gallons of water. So 1000 square foot roof collects 623 gallons per inch of rainfall.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=NliixNvK-vg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Well pit recharge&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Flood based recharging pits like above&lt;/li&gt;&#xA;&lt;li&gt;Desalination Co-ops (Agree to cover partial cost of plant construction/operation in exchange for percentage of water)&lt;/li&gt;&#xA;&lt;li&gt;Harvesting agricultural runoff&lt;/li&gt;&#xA;&lt;li&gt;Re-forestation programs.&lt;/li&gt;&#xA;&lt;li&gt;microcatchment . (Landscaping features)&#xA;The name &lt;em&gt;Zai&lt;/em&gt; pits refers to small pits are dug in which seed of annual or perennial crops are planted. The pits They are beneficial for soil because they increase insect and worm activity which in turn leads to a higher water infiltration when it rains, these pits are fertilized with manure (Human or animal) which also stores water better than sandy/clay soils. This intervention is most suitable for flat or gently sloped terrains (0-5% gradient) with a precipitation quantity of 350-600 mm. Other designs like &lt;em&gt;contour bunds, Negarim&lt;/em&gt; and other features catch water instead of letting it runoff and allow to infiltrate into the soil.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Dryer lands receive much more rain than we assume. The Netherlands, for example get's an average of 650mm (25.6 inches) of rainfall per year. Where as Xeric region Monterrey, Mexico has 680mm (26.8 inches) of rainfall. So How can the Netherlands despite having less rain, but have more fertile soils (besides a cooler climate) Be it degraded farmland or some xeric regions. Rainfall in some areas is Seasonal....in water stressed areas; water falls only at a peak of the year often a few weeks. Some regions have dry/wet seasons with six months of rain. Terrain: rain falls on slopes, hills and mountains and then flows out into streams and rivers that convey its runoff water into the sea. When areas are degraded or severely eroded, there is often a soil hardpan due to decades of compaction. The downside to no-till farming is that while it prevents soil erosion; it makes soil less permeable so only 15-25% of the water enters into the soil. The rest runs away.&#xA;Pre-Industrial farmers built land terraces and planted hills, modern farming eschews that. Newly built landscaping terraces collect 3x the water to infiltrate the soil.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2022-01-07T07:29:44.663" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23369" PostTypeId="2" ParentId="22371" CreationDate="2022-01-07T09:51:10.603" Score="0" Body="&lt;p&gt;Partially&#xA;the SOLUTION to POLLUTION is dilution. That brine goes &amp;quot;Somewhere&amp;quot; often reintroduced into the sea in intervals. The water cycle evaporates more water per day than we do. However the environmental harm of hypersaline brine on soil, etc&#xA;Basically Worldwide, desalination plants produce over 25 billion gallons of potable water a day....From an ocean that contains 350 QUINTILLION gallons of water.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2022-01-07T09:51:10.603" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23371" PostTypeId="2" ParentId="5169" CreationDate="2022-01-08T03:31:14.210" Score="1" Body="&lt;p&gt;According to the World Meteorological Organization, a record 1,825 mm (71.8 in) of rain fell in 24 hours at Foc-Foc (elevation: 2,990 m; 9,810 ft) on the French island territory of Réunion in the Indian Ocean on 7–8 January 1966. The event occurred during the passage of tropical cyclone Denise.&lt;/p&gt;&#xA;" OwnerUserId="26172" LastActivityDate="2022-01-08T03:31:14.210" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23372" PostTypeId="1" CreationDate="2022-01-08T15:33:44.347" Score="4" ViewCount="409" Body="&lt;p&gt;Why is the length of the apparent solar day less at aphelion than when compared to perihelion.&lt;/p&gt;&#xA;" OwnerUserId="26175" LastEditorUserId="2470" LastEditDate="2022-01-08T16:04:24.427" LastActivityDate="2022-01-15T20:10:05.453" Title="Perihelion Vs Aphelion position of Earth" Tags="|time|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23373" PostTypeId="2" ParentId="23372" CreationDate="2022-01-08T21:15:22.493" Score="4" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Why is the length of the apparent solar day less at aphelion than when compared to perihelion?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The TL;DR version:&lt;/p&gt;&#xA;&lt;p&gt;There's a simple answer to this question, which is that the Earth is orbiting the Sun slower at aphelion than it is at perihelion. A more correct answer (for the current epoch) is that it's a combination of the above effect and seasonal effects. An even more correct answer is that this isn't always the case. There are years far in the future (and far in the past) where the apparent solar day is longer at aphelion than it is at perihelion.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;The non-TL;DR version:&lt;/p&gt;&#xA;&lt;p&gt;It's due to the equation of time, or more precisely, the time derivative of which the equation.&lt;/p&gt;&#xA;&lt;p&gt;There are two primary factors that result in the length of a solar day differing from a mean solar day over the course of a year. These are the tilt of the Earth's axis with respect to its orbit about the Sun and the eccentricity of the Earth's orbit about the Sun.&lt;/p&gt;&#xA;&lt;p&gt;If the Earth's axial tilt (obliquity) was zero this question would be easily answered. The solar day is slightly longer than the sidereal day because the Earth needs to rotate a bit more than 360° degrees with respect to the stars to overcome the effects of the Earth's orbital angular velocity. The Earth's orbital angular velocity is slowest at aphelion and fastest at perihelion. This means an Earth with zero axial tilt would see its longest solar day at perihelion and its shortest at aphelion.&lt;/p&gt;&#xA;&lt;p&gt;Obliquity adds a confounding factor. If the Earth's orbit was circular, the shortest solar days would occur at the equinoxes and the longest at the solstices. The contribution of obliquity to the equation of time is a bit greater than is the contribution due to eccentricity. Since the frequency of the obliquity contribution is twice that of the eccentricity contribution, the obliquity contribution to the length of a solar day is more than twice that of eccentricity.&lt;/p&gt;&#xA;&lt;p&gt;Currently, perihelion occurs about a couple of weeks after the December solstice while aphelion occurs about a couple of weeks after the June solstice. This means that the effects due to eccentricity and due to obliquity are nearly in phase between the December solstice and perihelion but are nearly out of phase between the June solstice and aphelion.&lt;/p&gt;&#xA;&lt;p&gt;That the two effects are both positive and nearly in phase between the December solstice and perihelion  makes the longest solar day of the year occur between that solstice and perihelion. That the two effects are nearly out of phase June solstice and aphelion makes the solar day at aphelion slightly longer than average, but less than at perihelion.&lt;/p&gt;&#xA;&lt;p&gt;What about the shortest solar days of the year? These occur near the equinoxes, with the minimum near the September equinox slightly beating out the minimum near the March equinox.&lt;/p&gt;&#xA;&lt;p&gt;The plot below shows the equation of time (apparent solar time minus wall clock time) in blue and the length of an apparent solar day (time between one solar noon and the next) in red for the year 2022. I've subtracted 24 hours from the length of an apparent solar day for ease of plotting. Both curves show effects from eccentricity and axial tilt, with the blue curve (the equation of time) showing a greater effect from eccentricity than does the red curve.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MaEGh.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MaEGh.png&quot; alt=&quot;Equation of time (blue) and solar day length (red) for 2022&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The python3 script used to generate the above plot is&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import ephem&#xA;import matplotlib.pyplot as plt&#xA;&#xA;obs = ephem.Observer()&#xA;obs.lat, obs.lon = '0.0', '0.0'&#xA;obs.date = &amp;quot;2021/12/31 06:00&amp;quot;&#xA;obs.date = obs.next_transit(ephem.Sun())&#xA;prev_transit = obs.date&#xA;prev_dtup = prev_transit.tuple()&#xA;prev_doy = -1 + (prev_dtup[3] + (prev_dtup[4] + prev_dtup[5]/60.0)/60.0)/24.0&#xA;&#xA;dates = []&#xA;lods = []&#xA;lod_doys = []&#xA;eots = []&#xA;eot_doys = []&#xA;for i in range(365) :&#xA;    next_transit = obs.next_transit(ephem.Sun())&#xA;    lod = (next_transit-prev_transit-1)*86400&#xA;    dtup = next_transit.tuple()&#xA;    next_doy = i + (dtup[3] + (dtup[4] + dtup[5]/60.0)/60.0)/24.0&#xA;    eot = (dtup[3]-12)*60 + dtup[4] + dtup[5]/60.0&#xA;    dates.append(next_transit)&#xA;    lods.append(lod)&#xA;    lod_doys.append(0.5*(prev_doy+next_doy))&#xA;    eots.append(eot)&#xA;    eot_doys.append(next_doy)&#xA;    obs.date = next_transit&#xA;    prev_transit = next_transit&#xA;    prev_doy = next_doy&#xA;&#xA;red = 'tab:red'&#xA;blue = 'tab:blue'&#xA;black = 'k'&#xA;&#xA;fig, eot_plot = plt.subplots()&#xA;lod_plot = eot_plot.twinx()&#xA;&#xA;eot_plot.set_xlabel('Day of year')&#xA;eot_plot.set_xlim([0,365])&#xA;&#xA;lod_plot.plot([0,365],[0.0, 0.0], color=black, ls=&amp;quot;dotted&amp;quot;, lw=1)&#xA;&#xA;lod_plot.text(80, 24.0, &amp;quot;Apparent solar time ahead of clock&amp;quot;, color=blue)&#xA;lod_plot.text(80, 20.4, &amp;quot;Apparent solar day longer than 24h&amp;quot;,color=red)&#xA;lod_plot.text(80, -23.4, &amp;quot;Apparent solar time behind clock&amp;quot;, color=blue)&#xA;lod_plot.text(80, -27.0, &amp;quot;Apparent solar day shorter than 24h&amp;quot;,color=red)&#xA;&#xA;lod_plot.set_ylabel('Apparent solar day length - 24 hours (s)', color=red)&#xA;lod_plot.plot(lod_doys, lods, color=red, lw=2)&#xA;lod_plot.tick_params(axis='y', labelcolor=red)&#xA;lod_plot.set_ylim([-30.24,30.24])&#xA;&#xA;eot_plot.set_ylabel('Equation of time (m)', color=blue)&#xA;eot_plot.plot(eot_doys, eots, color=blue, lw=2)&#xA;eot_plot.tick_params(axis='y', labelcolor=blue)&#xA;eot_plot.set_ylim([-16.7,16.7])&#xA;&#xA;fig.tight_layout()&#xA;plt.show()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;A sundial will be ahead of a wall clock when the equation of time is positive, behind when the equation of time is negative. In a similar vein, the equation of time increases when the red curve is positive (the length of a solar day is greater than 24 hours) and decreases when the red curve is negative. The extrema in the blue curve (equation of time) corresponds to the zero crossings in the red curve (apparent solar day minus 24 hours). This is because the red curve is essentially a scaled version of the time derivative of the blue curve.&lt;/p&gt;&#xA;&lt;p&gt;What about the extrema in the red curve? These correspond closely to the equinoxes (local minima) and solstices (local maxima). The extrema in 2022 are at&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;2022/03/25 19:02:04 value = -18.078795180186802&lt;/li&gt;&#xA;&lt;li&gt;2022/06/20 21:56:34 value =  13.067898528426383&lt;/li&gt;&#xA;&lt;li&gt;2022/09/16 08:08:48 value = -21.470782163473018&lt;/li&gt;&#xA;&lt;li&gt;2022/12/23 00:49:59 value =  29.950310073944365&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The dates and times of the equinoxes and solstices in 2022 are&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;2022/03/20 15:33:21 (Vernal equinox)&lt;/li&gt;&#xA;&lt;li&gt;2022/06/21 09:13:57 (Summer solstice)&lt;/li&gt;&#xA;&lt;li&gt;2022/09/23 01:03:33 (Autumnal equinox)&lt;/li&gt;&#xA;&lt;li&gt;2022/12/21 21:48:00 (Winter solstice)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;These coincide within a few days of the extrema in the length of the solar day. The contributions from eccentricity do play a role in the length of a solar day, but it is minor compared to the role played by axial tilt.&lt;/p&gt;&#xA;&lt;p&gt;One could imagine times in the future where the effects caused by axial tilt and eccentricity are so far out of sync that the dominating effects of axial tilt that already overwhelm the effects due to eccentricity do so to such an extent that a solar day is longer at aphelion than it is at perihelion. If pyephem remains accurate for the next 18000 years (which is dubious), that happens in the year 19432 (and in many years after that). The dates and times of the six points of interest in 19432 are&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;19432/03/02 11:01:32 (March equinox)&lt;/li&gt;&#xA;&lt;li&gt;19432/04/29 06:27:28 (Aphelion)&lt;/li&gt;&#xA;&lt;li&gt;19432/06/02 23:54:23 (June solstice)&lt;/li&gt;&#xA;&lt;li&gt;19432/09/02 10:33:00 (September equinox)&lt;/li&gt;&#xA;&lt;li&gt;19432/10/19 16:39:16 (Perihelion)&lt;/li&gt;&#xA;&lt;li&gt;19432/12/01 13:51:43 (December solstice)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The equation of time / length of solar day graph for 19432 is shown below. The aphelion and perihelion dates (19432/04/29 06:27:28 and 19432/10/19 16:39:16) are marked with vertical lines. The solar day lengths at these points in time are nearly equal, but the solar day is slightly longer at aphelion than at perihelion.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ebyBn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ebyBn.png&quot; alt=&quot;Equation of time / length of solar day plot for the year 19432&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2022-01-15T20:10:05.453" LastActivityDate="2022-01-15T20:10:05.453" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23374" PostTypeId="2" ParentId="23285" CreationDate="2022-01-09T00:16:43.500" Score="1" Body="&lt;p&gt;One other possible source of surface temperature inversions involves bodies of water.&lt;/p&gt;&#xA;&lt;p&gt;On an unusually warm spring day in, let us say, Chicago, the air temperature is inherently warmer than the temperature of the Lake Michigan water below, which is still relatively cool from the preceding winter. So the water absorbs heat from the overlying air, creating a cool layer. Voila, a surface temperature inversion.&lt;/p&gt;&#xA;&lt;p&gt;The effect can be strong enough to capture pollution and create a dark layer on the eastern horizon at sunrise in Chicago. Dark enough, in fact, to filter the 2004 transit of Venus and enable seeing it with the unaided eye for a few minutes while the Sun was rising!&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2022-01-09T00:16:43.500" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23375" PostTypeId="2" ParentId="23285" CreationDate="2022-01-09T04:12:13.440" Score="0" Body="&lt;p&gt;Temperature inversions happen everywhere, but they're prone in valleys because the air has no where to go. Cold air is dense. So it drains from high elevation regions to lower ones and hugs as close to the ground as can. This makes valleys especially vulnerable to inversions ... These inversions occur when cold air gets trapped in the valley and a layer of warm air seals it from above; which makes storms in valleys particularly worrysome&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2022-01-09T04:12:13.440" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23376" PostTypeId="1" CreationDate="2022-01-09T04:32:10.477" Score="1" ViewCount="44" Body="&lt;p&gt;I am a student Pilot and basically we are asked to give weather briefing every morning using the charts shown here:&#xA;&lt;a href=&quot;https://mausam.imd.gov.in/imd_latest/contents/satellite.php#&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://mausam.imd.gov.in/imd_latest/contents/satellite.php#&lt;/a&gt;.&#xA;&lt;a href=&quot;https://mausam.imd.gov.in/imd_latest/contents/index_radar.php?id=Lucknow&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://mausam.imd.gov.in/imd_latest/contents/index_radar.php?id=Lucknow&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The problem is, nobody has any idea how to actually interpret these charts in a useful and correct manner, leading people to just say what they've always been hearing in the morning briefing. This could be detrimental to the safety of the trainee pilots here.&lt;/p&gt;&#xA;&lt;p&gt;So is there some sort of manual and/or any book which states how to analyse these charts? It'd be of great help if someone could answer, thanks!&lt;/p&gt;&#xA;" OwnerUserId="26176" LastActivityDate="2022-01-09T04:32:10.477" Title="Interpretation of certain maps related to weather" Tags="|meteorology|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23377" PostTypeId="1" AcceptedAnswerId="23393" CreationDate="2022-01-09T10:59:27.100" Score="2" ViewCount="446" Body="&lt;p&gt;For example, I am interested in making a simulation for some chemical species for 2019. I am planning to provide NCEP/GDAS FNL meteorological data at 0.25 degree and CAM-Chem chemical boundary layer. I want to know what time period of meteorological data and chemical boundary layer should I provide for my simulation?&lt;/p&gt;&#xA;" OwnerUserId="12660" LastEditorUserId="12660" LastEditDate="2022-01-09T18:19:07.463" LastActivityDate="2022-01-15T06:56:48.897" Title="Is spin-up really required to run the WRF-Chem model and if so, what determines the time period of the spin-up?" Tags="|models|climate-models|atmosphere-modelling|wrf|wrf-chem|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="23380" PostTypeId="1" CreationDate="2022-01-11T20:56:08.760" Score="2" ViewCount="118" Body="&lt;p&gt;When talking about rocks, i.e. an aggregate of minerals, which type would be the &amp;quot;healthiest&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;I'm &lt;em&gt;&lt;strong&gt;not&lt;/strong&gt;&lt;/em&gt; talking about some voodoo crystal-healing stuff here, just if there is any rock formation that has a relatively high number and proportion of &lt;strong&gt;minerals that the body needs&lt;/strong&gt; e.g. magnesium, potassium, zinc etc that would &lt;em&gt;&lt;strong&gt;leach into water (like mineral water)&lt;/strong&gt;&lt;/em&gt; for example if you live in an area where that rock is prevalent where the community takes their groundwater&lt;/p&gt;&#xA;&lt;p&gt;At the same time as having a relatively &lt;strong&gt;low number of minerals that the body does not need&lt;/strong&gt; (or that would eventually also be harmful at high quantities) e.g. silica, uranium, talcum etc&lt;/p&gt;&#xA;" OwnerUserId="26189" LastEditorUserId="2470" LastEditDate="2022-01-11T21:19:56.580" LastActivityDate="2022-01-12T03:06:37.520" Title="What is the &quot;healthiest&quot; rock?" Tags="|mineralogy|rocks|minerals|groundwater|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23381" PostTypeId="2" ParentId="23380" CreationDate="2022-01-12T03:06:37.520" Score="2" Body="&lt;p&gt;There is no good answer to this questions.&lt;/p&gt;&#xA;&lt;p&gt;All rocks contain all naturally occurring elements in the periodic table. Greater contents of an element in a rock do not necessarily translate into its abundance in the groundwater.&lt;/p&gt;&#xA;&lt;p&gt;For example, uranium contents are usually elevated in granites relative to basalts. But whether this uranium can be leached out depends on how old the rock is (5 million years is young, 1500 million years is old), which specific minerals are hosting the uranium (zircon will not readily give up its uranium), the oxidation state of the groundwater (lots of organic matter will immobilise uranium in its reduced state).&lt;/p&gt;&#xA;&lt;p&gt;Limestone, for example, can have very low uranium contents, but it would readily acquire uranium from fluids that contain uranium from elsewhere. It would not be easy to distinguish the two types of limestone.&lt;/p&gt;&#xA;&lt;p&gt;As for silica that you mentioned in your question, it is dangerous when silica dust is inhaled into the lungs. I am not aware of any problems with silica in groundwater (and don't worry about it - it's a very insoluble element).&lt;/p&gt;&#xA;&lt;p&gt;The only way to know for sure what are the levels of the various elements in different types of groundwater, is to measure them. Trying to predict their composition based on the rock types is not far from guesswork.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2022-01-12T03:06:37.520" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23382" PostTypeId="1" CreationDate="2022-01-12T12:12:42.043" Score="2" ViewCount="62" Body="&lt;p&gt;Natural Gas fields as the name suggests are a source of natural gas which in turn are a major source of energy for almost every economy.&lt;/p&gt;&#xA;&lt;p&gt;Recently in news is Gateway to Hell of Turkmenistan, a natural gas field crater.&#xA;I was surprised to know that it had been burning for 5 decades.&lt;/p&gt;&#xA;&lt;p&gt;It must have produced a lot of energy till now.&lt;/p&gt;&#xA;&lt;p&gt;Is it possible to use the fire as an energy source?&lt;/p&gt;&#xA;" OwnerUserId="23274" LastActivityDate="2022-01-13T16:35:56.177" Title="Natural Gas fields as power sources" Tags="|fossils|fossil-fuel|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23383" PostTypeId="2" ParentId="23382" CreationDate="2022-01-12T15:33:11.757" Score="0" Body="&lt;p&gt;If it was profitable; the way to handle this situation is to drill from a safe distance to the source of the gas and flood with cement to stop the gas flow. Then drill conventional gas wells to produce the gas for use. A variation of the control of gas/oil wells in Kuwait that were sabotaged by Saddam Husain. Not being a petroleum engineer , I am speculation at the use of cement . An evaluation of real information would be necessary to pick a good solution. The Wiki article indicates it is a failed gas well drilled by Russia, if so, drilling to an appropriate point in the original well casing to inject cement would be very feasible. Being a well , that also means the gas may be coming from a reservoir miles below the surface.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastEditorUserId="8409" LastEditDate="2022-01-13T16:35:56.177" LastActivityDate="2022-01-13T16:35:56.177" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23384" PostTypeId="2" ParentId="23382" CreationDate="2022-01-12T18:13:58.473" Score="3" Body="&lt;p&gt;If one really wanted to, one could find a way to use the heat generated by &lt;a href=&quot;https://en.wikipedia.org/wiki/Darvaza_gas_crater&quot; rel=&quot;nofollow noreferrer&quot;&gt;Darvaza gas crater&lt;/a&gt;  in Turkemenistan. Adapting the method used to construct the replacement &lt;a href=&quot;https://en.wikipedia.org/wiki/Chernobyl_Nuclear_Power_Plant_sarcophagus&quot; rel=&quot;nofollow noreferrer&quot;&gt;sarcophagus at Chernobyl&lt;/a&gt; that was rolled into place in 2016 something could have been constructed a safe distance from the fire crater &amp;amp; then rolled over make use of the heat.&lt;/p&gt;&#xA;&lt;p&gt;There are two problems with this however. The first is how much power could be generated from a &amp;quot;roll over the crater power station&amp;quot; given that it is not an ideal way to make a power plant. The second problem is the fire crater is locate in a wilderness region remote from people who could use the energy that might be generated. Power transmission lines would need to be constructed which would add to the cost and if the amount of power that could be generated was modest at best the cost may not justify doing anything.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-01-12T18:13:58.473" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23385" PostTypeId="2" ParentId="23256" CreationDate="2022-01-12T19:39:50.677" Score="1" Body="&lt;p&gt;In order to equilibrate a geode with the ocean, there must be a location where the density of the water matches that of the geode including the latter's enclosed empty space. But water in the oceans is very near to an incompressible fluid; its density varies only over a very narrow range. Thus if a geode (or a sinking ship) is dense enough to sink at all from the top of the ocean, in all likelihood it remain dense enough to go all the way to the bottom.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2022-01-12T19:39:50.677" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23386" PostTypeId="2" ParentId="23256" CreationDate="2022-01-12T23:35:01.083" Score="5" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Would it sink down to a certain altitude based on how hollow the geode&#xA;is or would it float on top or sink to the bottom?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Most geodes are made of quartz or calcite. Their densities are somewhere between 2.6 and 2.7 g/cm&lt;sup&gt;3&lt;/sup&gt;. Let's round it up to 3 for simplicity. This is three times the density of water.&lt;/p&gt;&#xA;&lt;p&gt;So, for a geode to float it needs to be at least two thirds empty volume.&lt;/p&gt;&#xA;&lt;p&gt;But! This is assuming what's inside is air. Geodes form from various fluids or gases. When they formed, if they had a fluid inside, and it is no longer inside, then the geode is not hermetically sealed. This means that once you drop it in the ocean, water will start leaking inside and it will eventually sink. If the geode formed from gas, and it is sealed, then yes there is a chance it will keep on floating.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;And could geodes form in the ocean and then break loose and be&#xA;released into the ocean?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;No, because if they form in the ocean, they have seawater inside. Not air. So their density cannot be lower than that of seawater, and they cannot float.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2022-01-12T23:35:01.083" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23387" PostTypeId="1" CreationDate="2022-01-13T00:38:11.040" Score="7" ViewCount="69" Body="&lt;p&gt;The pineapple express is a colloquial term for the strong atmospheric river produced by the polar jet stream, which drives excessive moisture and warmer air towards north-western North America.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/rPDay.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rPDay.jpg&quot; alt=&quot;Pineapple express&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;With the arrival of said atmospheric river, the coast can often see hundreds of millimeters of precipitation, sometimes resulting in flooding.&lt;/p&gt;&#xA;&lt;p&gt;Under the right conditions, what if the pineapple express were to collide with cold arctic air along the coast, and in turn produce outrageous amounts of snow? Considering how 1mm of rainfall translates roughly to 1cm of snowfall, this could hypothetically result in meters of snow within a fairly short timespan.&lt;/p&gt;&#xA;&lt;p&gt;Are these kind of conditions possible in theory? Or are the conditions needed to form a pineapple express mutually exclusive with the conditions needed for such cold conditions on the pacific northwest?&lt;/p&gt;&#xA;" OwnerUserId="22327" LastActivityDate="2022-01-13T00:38:11.040" Title="Could the Pineapple Express collide with cold air, resulting in extreme snowfall?" Tags="|meteorology|atmosphere|precipitation|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23388" PostTypeId="2" ParentId="10494" CreationDate="2022-01-14T05:29:42.990" Score="1" Body="&lt;p&gt;you can use this:&#xA;this define integrated vapor transport(IVT)  or Moisture Flux:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt; 'define qu=vint(const(lon,1000,-a),shum.1*uwind.2,300)'  &#xA; 'define qv=vint(const(lon,1000,-a),shum.1*vwind.3,300)'  &#xA; 'define VIMFC=mag(qu,qv)'&#xA; 'd VIMFC'&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;best regards&lt;/p&gt;&#xA;" OwnerUserId="26203" LastEditorUserId="6298" LastEditDate="2022-01-14T07:07:41.050" LastActivityDate="2022-01-14T07:07:41.050" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23389" PostTypeId="1" CreationDate="2022-01-14T16:02:23.580" Score="4" ViewCount="96" Body="&lt;p&gt;Which has higher &lt;span class=&quot;math-container&quot;&gt;$\delta {}^{18} \text{O}$&lt;/span&gt;, saline water or freshwater?&#xA;I searched for this question and found many researches about the relationship between &lt;span class=&quot;math-container&quot;&gt;$\delta {}^{18} \text{O}$&lt;/span&gt; and salinity. But, I'm not sure why δ18O differs by salinity.&#xA;Some researches say that &lt;span class=&quot;math-container&quot;&gt;$\delta {}^{18} \text{O}$&lt;/span&gt; is high in saline water and low in freshwater.&lt;/p&gt;&#xA;&lt;p&gt;Why would &lt;span class=&quot;math-container&quot;&gt;$\delta {}^{18} \text{O}$&lt;/span&gt; differs by salinity, especially of seawater and freshwater?&lt;/p&gt;&#xA;&lt;p&gt;EDIT: I was just curious if I can determine whether a diadromous fish was anadromous or catadromous by examining &lt;span class=&quot;math-container&quot;&gt;$\delta {}^{18} \text{O}$&lt;/span&gt; value of the fish fossil.&lt;/p&gt;&#xA;&lt;p&gt;In &lt;a href=&quot;https://www.nature.com/articles/s41598-021-03232-9#Fig2&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; research, how can we know that the fish was anadromous by its &lt;span class=&quot;math-container&quot;&gt;$\delta {}^{18} \text{O}$&lt;/span&gt; value?&lt;/p&gt;&#xA;" OwnerUserId="26205" LastEditorUserId="26205" LastEditDate="2022-01-24T14:26:55.200" LastActivityDate="2022-01-24T14:26:55.200" Title="Oxygen-18 in saline water and freshwater" Tags="|oxygen|salinity|isotopic|" AnswerCount="0" CommentCount="3" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23390" PostTypeId="1" CreationDate="2022-01-15T00:04:36.147" Score="13" ViewCount="2003" Body="&lt;p&gt;I understand that volcanoes occur where oceanic crust is subducted under continental crust such as the Andes. However, they don't occur at places like the Himalayas and Alps where continental crust is colliding with another chuck of continental plate. Why the difference? Is it that the continental crust isn't forced deep enough? Or is the continental crust too dry? Or something else?&lt;/p&gt;&#xA;" OwnerUserId="26208" LastActivityDate="2022-01-26T01:08:02.833" Title="Why are there no volcanoes where continents collide with each other?" Tags="|plate-tectonics|volcanology|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23393" PostTypeId="2" ParentId="23377" CreationDate="2022-01-15T06:56:48.897" Score="1" Body="&lt;p&gt;Generally, spin up is necessary. To give context, look at how the model initializes. Does that look anything like a real chemical field? If you don’t have the eye for such things, examine the RMSE or other error metrics and compare them to other studies. Odds are, probably not. So you have to supply the model with emissions data and give a long enough period for it to seem at least plausible.&lt;/p&gt;&#xA;&lt;p&gt;When I was using WRF-Chem to simulate &lt;span class=&quot;math-container&quot;&gt;$\ce{O3}$&lt;/span&gt;, I used a couple days for the emission of &lt;span class=&quot;math-container&quot;&gt;$\ce{NO_x}$&lt;/span&gt; to be somewhat representative.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2022-01-15T06:56:48.897" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23394" PostTypeId="2" ParentId="23390" CreationDate="2022-01-15T08:15:10.777" Score="5" Body="&lt;p&gt;Two major reasons, crustal thickening and thermochemical interactions.&lt;/p&gt;&#xA;&lt;p&gt;Heat plumes, whether from crustal recycling or the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mantle_plume&quot; rel=&quot;noreferrer&quot;&gt;deep mantle&lt;/a&gt;, can only melt through so much rock before they lose heat and either convect away or freeze on/in to the rock they have penetrated as intrusive deposits. Crustal thickening as rock piles up at convergent margins means that plumes of hot rock simply don't have enough energy to melt through into range of the surface. Thus instead of surface volcanism melting results in subsurface intrusion of rock.&lt;/p&gt;&#xA;&lt;p&gt;The thermochemical side is more of a why there &lt;em&gt;are&lt;/em&gt; volcanoes at subduction zones; the seabed deposits on the the subducting plate contain a number of minerals that, when heated sufficiently, break down and release compounds, mainly water, that transfer heat from the deeper mantle into the base of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Asthenosphere&quot; rel=&quot;noreferrer&quot;&gt;asthenosphere&lt;/a&gt;. This heat transfer causes melting of the overriding crust that feeds volcanic activity above the subducted plate.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2022-01-15T08:15:10.777" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23395" PostTypeId="1" AcceptedAnswerId="23396" CreationDate="2022-01-15T08:48:57.150" Score="5" ViewCount="371" Body="&lt;p&gt;According to Greek mythology, &lt;strong&gt;halcyon days&lt;/strong&gt; are&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;the seven days in winter when storms never occur. &lt;a href=&quot;https://en.wikipedia.org/wiki/Alcyone_and_Ceyx#Halcyon_days&quot; rel=&quot;nofollow noreferrer&quot;&gt;[Wikipedia]&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I assume that Ancient Greeks noticed a period in winter during which the weather was especially calm, so they came up with a myth to explain it.&lt;/p&gt;&#xA;&lt;p&gt;Is there such a concept in meteorology?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;According to the article &lt;a href=&quot;https://greekreporter.com/2022/01/10/halcyon-days-the-unique-greek-weather-phenomenon/&quot; rel=&quot;nofollow noreferrer&quot;&gt;“Halcyon Days: When Spring Appears in the Middle of Winter in Greece”&lt;/a&gt; from Greek Reporter, the Halcyon days supposedly take place some time between 15 December to 15 February, most often between 16 to 31 January.&lt;/p&gt;&#xA;" OwnerUserId="26117" LastEditorUserId="26117" LastEditDate="2022-01-15T13:43:00.977" LastActivityDate="2022-01-15T21:08:29.860" Title="Are halcyon days an actual phenomenon?" Tags="|meteorology|rain|storms|winter|geomythology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23396" PostTypeId="2" ParentId="23395" CreationDate="2022-01-15T09:07:48.203" Score="6" Body="&lt;p&gt;The story of Halcyon days is that there is a period of 7 (or 14?) days around midwinter (on the 21st of December) on which Aeolus does not make the wind to blow - to allow the Kingfisher, 'Alcyone to lay her eggs.  This is a myth.&lt;/p&gt;&#xA;&lt;p&gt;There is no predictable period of calm weather in midwinter, although periods of stormy and calm weather can alternate, on several time scales. There are periods of a week or so that are calm, but they do not occur regularly.&lt;/p&gt;&#xA;&lt;p&gt;There are lots of examples of storms in the Mediterranean and across the Northern Hemisphere, occurring on or near to the 21st of December, the time when according to the myth, storms don't occur:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;[In] 1967 An F4 tornado traveled 33 miles across Iron and Washington Counties in Missouri [...] The tornado killed 3 and injured 52 others. (&lt;a href=&quot;https://www.weather.gov/abr/This_Day_in_Weather_History_Dec_21&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;[In 2021] Severe weather forecast across much of Greece and Cyprus due to Storm Carmel through at least Dec. 20. (&lt;a href=&quot;https://www.garda.com/crisis24/news-alerts/557621/greece-cyprus-adverse-weather-associated-with-storm-carmel-forecast-across-southern-and-central-greece-and-cyrpus-through-at-least-dec-20&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Of course there are more stormy and less stormy days.  Most, if not all winters will have a period of high pressure, with gentle winds and little preciptiation. These can last a week or more. But you cannot predict with accuracy when these periods will occur from more than a few days in advance.&lt;/p&gt;&#xA;" OwnerUserId="9563" LastEditorUserId="9563" LastEditDate="2022-01-15T21:08:29.860" LastActivityDate="2022-01-15T21:08:29.860" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23397" PostTypeId="2" ParentId="23390" CreationDate="2022-01-15T09:41:20.807" Score="13" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Or is the continental crust too dry?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Exactly this. Continental collision zones are actually full of volcanic rocks, which formed at the time before it was a continental collision zone. The Wikipedia article on the Geology of the Himalaya has a nice &lt;a href=&quot;https://en.wikipedia.org/wiki/Geology_of_the_Himalaya#Indus_Suture_Zone_(ISZ)_(or_Yarlung-Tsangpo_Suture_Zone)_tectonic_plate&quot; rel=&quot;noreferrer&quot;&gt;summary of the suture zone&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;Dras Volcanics&amp;quot;: are relicts of a &amp;quot;Late Cretaceous&amp;quot; to &amp;quot;Late&#xA;Jurassic&amp;quot; volcanic island arc and consist of basalts, dacites,&#xA;volcanoclastites, pillow lavas and minor radiolarian cherts&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;Indus Suture Zone&amp;quot;: represents the northern limit of the Himalaya.&#xA;Further to the North is the so-called &amp;quot;Transhimalaya&amp;quot;, or more locally&#xA;&amp;quot;Ladakh Batholith&amp;quot;, which corresponds essentially to an active margin&#xA;of Andean type. Widespread volcanism in this volcanic arc was caused&#xA;by the melting of the mantle at the base of the Tibetan bloc,&#xA;triggered by the dehydration of the subducting Indian oceanic crust.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So yes, there were quite a lot of volcanoes just before the collision itself, when you still had an island arc due to the oceanic crust part of the Indian plate subducting below the continental crust to the north of it. Once that has been decapitated and dropped into the mantle, you had dry continental crust colliding with another chunk of dry continental crust. There is some melting here and there (leading to mostly plutonic rocks including the famous Himalayan leucogranites), but nothing serious.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2022-01-15T09:41:20.807" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23398" PostTypeId="2" ParentId="22925" CreationDate="2022-01-15T17:03:35.507" Score="0" Body="&lt;p&gt;We agree that additional evaporation enhances energy transport from the surface to the atmosphere and intensifies the hydrological cycle and cloud formation, and that some of the most serious climate change issues such as:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Rapidly expanding deserts with forest and species extinction&lt;/li&gt;&#xA;&lt;li&gt;Accelerated rising sea level and earth temperature&lt;/li&gt;&#xA;&lt;li&gt;In many places sinking groundwater levels, drainage of the regions and continents&lt;/li&gt;&#xA;&lt;li&gt;Periods of drought with temperature records and heavy rain events with flooding&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;…are all linked to the presence or absence of water !&lt;/p&gt;&#xA;&lt;p&gt;You can read here what a slightly modified concept for reducing sea level rise through water and rain retention and for cooling the Earth's temperature through additional cloud albedo could look like:&#xA;&lt;a href=&quot;https://climate-protection-hardware.webnode.com/english/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://climate-protection-hardware.webnode.com/english/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It differs in:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;that it is not sea water, that is discharged and evaporated, but clean spring, river or rain water, which not only guarantees additional evaporation rates, but also improves groundwater aquifers, soil moisture, photosynthesis and CO&lt;sub&gt;2&lt;/sub&gt; absorption.&lt;/li&gt;&#xA;&lt;li&gt;that the water does not evaporate on an uninhabited, barren desert surface, but where water scarcity is already putting the global population, agriculture and nature under enormous pressure.&lt;/li&gt;&#xA;&lt;li&gt;that the concept is not based on a single, expensive large-scale project, but results in millions of small-scale, cheap and quickly implementable measures.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;In principle, it is a simple, worldwide request to politics, agriculture, industry, but also to private individuals, wherever/whenever possible, to create extensive water reserves and also to save water, in order to generously use it in plant growth, evaporation, clouds and &amp;quot;water cooling&amp;quot; during periods of drought in spring and summer.&lt;/p&gt;&#xA;&lt;p&gt;The global strategy starts with rain barrels with overflow on unsealed areas...and explains many other private and municipal measures, which you can find on the website.&lt;/p&gt;&#xA;&lt;p&gt;There you will also find some links to scientific papers, which should support this holistic, alternative climate protection strategy.&lt;/p&gt;&#xA;" OwnerUserId="26198" LastEditorUserId="2470" LastEditDate="2022-01-16T00:11:11.473" LastActivityDate="2022-01-16T00:11:11.473" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23400" PostTypeId="2" ParentId="7212" CreationDate="2022-01-15T20:36:07.973" Score="3" Body="&lt;p&gt;The question doesn't say if the pond is stream fed. If it is groundwater fed - it will take much longer to freeze, due to the fact that the groundwater is moving through an insulated body (ground) and continually adds warm water to the system. This will most always be noticeable at an edge of the pond that never freezes over or takes much longer and colder temperatures to cool before it can freeze.&lt;/p&gt;&#xA;" OwnerUserId="26213" LastEditorUserId="2470" LastEditDate="2022-01-16T00:04:24.200" LastActivityDate="2022-01-16T00:04:24.200" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23401" PostTypeId="1" AcceptedAnswerId="23404" CreationDate="2022-01-16T12:32:29.877" Score="2" ViewCount="421" Body="&lt;p&gt;What is the exact difference between a crystal and a mineral?&lt;/p&gt;&#xA;" OwnerUserId="26216" LastEditorDisplayName="user20559" LastEditDate="2022-01-16T12:52:16.557" LastActivityDate="2022-01-16T17:55:28.550" Title="Difference between crystal and mineral" Tags="|geology|mineralogy|crystallography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23402" PostTypeId="1" AcceptedAnswerId="23403" CreationDate="2022-01-16T14:51:00.983" Score="-1" ViewCount="93" Body="&lt;p&gt;In NPR's podcast and transcript &lt;a href=&quot;https://www.npr.org/2022/01/15/1073331370/for-50-years-the-gates-of-hell-crater-has-burned-now-officials-want-to-put-it-ou&quot; rel=&quot;nofollow noreferrer&quot;&gt;For 50 years, 'The Gates Of Hell' crater has burned. Now officials want to put it out&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;NPR's Scott Simon speaks to George Kourounis, Royal Canadian Geographical Society's explorer-in-residence, about the possible closing of &amp;quot;The Gates of Hell,&amp;quot; a natural gas field in Turkmenistan.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;SIMON: You sound like you like this place.&lt;/p&gt;&#xA;&lt;p&gt;KOUROUNIS: &lt;strong&gt;Twelve people have stood on the surface of the moon, but only one person has been to the Gates of Hell.&lt;/strong&gt; And I was very fortunate to be able to go there. And I even have the Guinness World Record certificate above my desk to help commemorate that. So I get a kick out of that every time I see it.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Exactly what &amp;quot;Gates of Hell&amp;quot; Guinness World Record did Royal Canadian Geographical Society's explorer-in-residence George Kourounis receive?&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Twelve people have stood on the surface of the moon, but only one person has been to the Gates of Hell.&amp;quot; Exactly what Guinness World Record did Royal Canadian Geographical Society's explorer-in-residence George Kourounis receive?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2022-01-16T22:34:54.947" Title="&quot;Twelve people have stood on the moon, but only one person has been to the Gates of Hell.&quot; What Guinness World Record did George Kourounis receive?" Tags="|methane|fire|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23403" PostTypeId="2" ParentId="23402" CreationDate="2022-01-16T16:24:30.527" Score="2" Body="&lt;p&gt;According to the &lt;a href=&quot;https://www.guinnessworldrecords.com/world-records/513942-first-person-to-reach-the-bottom-of-darvaza-gas-crater&quot; rel=&quot;nofollow noreferrer&quot;&gt;Guinness Book of World Records&lt;/a&gt; site, George Kourounis holds the record as the first person to reach the bottom:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The first person to reach the bottom of Darvaza gas crater is George Kourounis (Canada), and was achieved at the Darvaza gas crater in Darvaza, Turkmenistan on 6 October 2013.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;More details from the same &lt;a href=&quot;https://www.guinnessworldrecords.com/world-records/410517-first-person-to-explore-the-darvaza-crater&quot; rel=&quot;nofollow noreferrer&quot;&gt;website&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In November 2013, explorer and storm-chaser George Kourounis (Canada) became the first known person to venture into the blazing Darvaza Crater located in a natural gas field in the Karakum Desert, Turkmenistan. Also known as the “Door to Hell”, the fiery feature has been ablaze since 1971, when it’s widely believed that the ground caved in as a result of drilling and the pit was intentionally set alight to burn off the leaking gas. Wearing an insulated aluminium suit and using a custom-made Kevlar climbing harness, Kourounis descended to the crater’s base to collect rock samples. Later lab tests revealed bacteria living on the rocks, proving that life can survive the extreme temperatures which reach in excess of 1,000°C (1,830°F).&lt;/p&gt;&#xA;&lt;p&gt;The crater is 69 m (225 ft) wide and 30 m (99 ft) deep.&lt;/p&gt;&#xA;&lt;p&gt;Kourounis' expedition was financially backed by National Geographic and travel company Kensington Tours.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="8163" LastEditorUserId="2470" LastEditDate="2022-01-16T22:34:54.947" LastActivityDate="2022-01-16T22:34:54.947" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23404" PostTypeId="2" ParentId="23401" CreationDate="2022-01-16T17:55:28.550" Score="2" Body="&lt;p&gt;A &lt;strong&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Crystal&quot; rel=&quot;nofollow noreferrer&quot;&gt;crystal&lt;/a&gt;&lt;/strong&gt;,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;is a solid material whose constituents (such as atoms, molecules, or ions) are arranged in a highly ordered microscopic structure, forming a crystal lattice that extends in all directions.&lt;/p&gt;&#xA;&lt;p&gt;Microscopically, a single crystal has atoms in a near-perfect periodic arrangement; a polycrystal is composed of many microscopic crystals (called &amp;quot;crystallites&amp;quot; or &amp;quot;grains&amp;quot;); and an amorphous solid (such as glass) has no periodic arrangement even microscopically.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kiled.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kiled.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Examples of crystals include diamond (C), table salt (NaCl), snow and ice (H&lt;sub&gt;2&lt;/sub&gt;O) and chalcopyrite (CuFeS&lt;sub&gt;2&lt;/sub&gt;).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Mineral&quot; rel=&quot;nofollow noreferrer&quot;&gt;Minerals&lt;/a&gt; however,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The international Mineralogical Association requirements for classification minerals are:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;It must be a naturally occurring substance formed by natural&#xA;geological processes, on Earth or other extraterrestrial bodies.&lt;/li&gt;&#xA;&lt;li&gt;It must be a solid substance in its natural occurrence. A major&#xA;exception to this rule is native mercury.&lt;/li&gt;&#xA;&lt;li&gt;It must have a well-defined crystallographic structure; or, more&#xA;generally, an ordered atomic arrangement.&lt;/li&gt;&#xA;&lt;li&gt;It must have a fairly well defined chemical composition. However,&#xA;certain crystalline substances with a fixed structure but variable&#xA;composition may be considered single mineral species.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Consequently, snow and ice are crystals but they are not minerals.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-01-16T17:55:28.550" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23405" PostTypeId="2" ParentId="23390" CreationDate="2022-01-17T04:50:14.580" Score="-1" Body="&lt;p&gt;The simplified answer is that most volcanoes occur where the crust is thin.  This allows magma from the Earth's upper mantle to rise and create trouble.  Most active volcanos are found at the bottom of the sea where plates are spreading!  We just had one erupt near Tonga.  Many island chains are made from volcanic activity.  Plates that collide make mountains, not necessarily volcanoes.&lt;/p&gt;&#xA;" OwnerUserId="26219" LastActivityDate="2022-01-17T04:50:14.580" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23407" PostTypeId="1" AcceptedAnswerId="23408" CreationDate="2022-01-17T13:52:46.053" Score="2" ViewCount="70" Body="&lt;p&gt;I'm in my late thirties and decided to get back to studying. I want to learn petroleum geology but it's been 10 years since I last opened any book, so I basically forgot tons of stuff that I learnt.&lt;/p&gt;&#xA;&lt;p&gt;I want to know what I need to relearn before enrolling in petroleum geology. What are the (math, physics, chemistry, etc) prerequisites that I need to relearn and what math, physics, and chemistry topics should I expect in this field?&lt;/p&gt;&#xA;" OwnerUserId="26225" LastEditorUserId="28050" LastEditDate="2022-01-17T18:24:08.093" LastActivityDate="2022-01-17T18:47:45.640" Title="What are the prerequisites for petroleum geology?" Tags="|geology|petroleum|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23408" PostTypeId="2" ParentId="23407" CreationDate="2022-01-17T18:47:45.640" Score="5" Body="&lt;p&gt;&lt;strong&gt;I think the shortest fair answer is there are no special prerequisites beyond a general, high-school-level education in maths and science.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;It's a difficult question to answer directly, because petroleum geoscience is a very broad field including:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Geology: the study of sedimentary basins, especially sources rocks, reservoirs rocks, and structural geology (folds, fractures, faults). Mostly involves making systematic observations, mapping, and data interpretation.&lt;/li&gt;&#xA;&lt;li&gt;Geophysics: remote sensing of geology using various physical measurements, such as gravity, electromagnetics, and seismic waves. Involves lots of computers and digital analysis, and quite a bit of maths and applied (especially signal processing and linear algebra).&lt;/li&gt;&#xA;&lt;li&gt;Various other rather niche areas (at least in terms of the number of specialists around) such as geochemistry, palaeontology, mineralogy, field geology, and so on.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;It's so broad that I daresay you can find an area that would appeal to almost anyone with an interest in science. If you're more quantitative (interested in maths and computing), then you'll find lots of friends in geophysics, but there are plenty of highly quantitative geologists and geochemists (and arguably those fields are more in need of nerds than geophysics is).&lt;/p&gt;&#xA;&lt;p&gt;I think it's fair to say that most petroleum geoscientists started with a general degree in geology, geophysics, or some related discipline, perhaps followed it up with a post-graduate degree, then got a job in petroleum. They didn't train in petroleum geology &lt;em&gt;per se&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;This may or may not be relevant to your situation, but you should know that petroleum geoscience is in decline as a discipline. Maybe that means there will be opportunities in the future, but right now and for the foreseeable future it means that there's a lot of under-employed earth scientists. If finding a job is your main motivation, my unsolicited personal advice would be to downplay the 'petroleum' aspect, stick to pure sciences and skills, and maybe look at other areas of applied geoscience, such as mining, geothermal (very small), or geospatial (GIS, basically).&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2022-01-17T18:47:45.640" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23411" PostTypeId="2" ParentId="22379" CreationDate="2022-01-18T16:21:20.073" Score="1" Body="&lt;p&gt;Flow turbines - also called power buoys, would be the most suitable form of hydro power for the Amazon and its many tributaries. With a maximum of 70 kW per buoy at the moment, the Amazon needs a lot of these power plants to become world champion in hydro power.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.aqualibre.at/files/pressemitteilung_aqualibre_powerfluxx_englisch.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.aqualibre.at/files/pressemitteilung_aqualibre_powerfluxx_englisch.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26198" LastEditorUserId="2470" LastEditDate="2022-01-18T17:05:55.170" LastActivityDate="2022-01-18T17:05:55.170" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23412" PostTypeId="1" CreationDate="2022-01-19T05:49:44.547" Score="1" ViewCount="43" Body="&lt;p&gt;Can &lt;a href=&quot;https://en.wikipedia.org/wiki/Volcanic_cone&quot; rel=&quot;nofollow noreferrer&quot;&gt;volcanic cones&lt;/a&gt;, similar to the one shown below form from fissure type of volcanoes?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/k9Arh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/k9Arh.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26216" LastEditorUserId="2470" LastEditDate="2022-01-19T06:28:05.263" LastActivityDate="2022-01-19T06:28:05.263" Title="Volcanic Cones - Fissure Type" Tags="|volcanology|geomorphology|mountain-building|" AnswerCount="0" CommentCount="1" ClosedDate="2022-01-21T13:13:14.927" ContentLicense="CC BY-SA 4.0" />
  <row Id="23413" PostTypeId="1" CreationDate="2022-01-19T15:29:52.777" Score="1" ViewCount="205" Body="&lt;p&gt;A Facebook post containing an image from &lt;a href=&quot;https://www.facebook.com/groups/1328285517592675/&quot; rel=&quot;nofollow noreferrer&quot;&gt;@TheGretaEffect&lt;/a&gt; and &lt;a href=&quot;https://www.facebook.com/groups/1328285517592675/permalink/1363385557416004/&quot; rel=&quot;nofollow noreferrer&quot;&gt;actual post can be found here&lt;/a&gt; mentions the development of a plane build entirely of hemp products and fueled with hemp oil.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7si0m.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7si0m.jpg&quot; alt=&quot;Facebook image&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I was thinking that in this day and age where more emphasis is on net zero carbon emissions, would this be net zero or net negative in CO&lt;sub&gt;2&lt;/sub&gt;e emissions?&lt;/p&gt;&#xA;&lt;p&gt;Hemp has excellent carbon &lt;a href=&quot;https://www.usgs.gov/faqs/what-carbon-sequestration&quot; rel=&quot;nofollow noreferrer&quot;&gt;sequestration&lt;/a&gt; when grown according to &lt;a href=&quot;https://ec.europa.eu/environment/forests/pdf/respondents-additional-inputs/European%2520Industrial%2520Hemp%2520Association%2520(EIHA).pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;one article I found&lt;/a&gt; from the European Industrial Hemp Association (EIHA).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;One hectare of industrial hemp can absorb 15 tonnes of CO2 per hectare. Hemp's rapid growth makes it one of the fastest CO2-to-biomass conversion tools available, more efficient than agro-forestry.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="21081" LastEditorUserId="21081" LastEditDate="2022-01-20T05:38:38.887" LastActivityDate="2022-01-21T19:31:09.997" Title="Does use of hemp oil for transport fuel produce a net positive CO2e?" Tags="|climate-change|co2|emissions|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23414" PostTypeId="1" CreationDate="2022-01-19T21:42:13.477" Score="4" ViewCount="103" Body="&lt;p&gt;I am looking for a book about waves in the context of Earth Science, the two main topics I have in mind are ocean waves and seismic waves.&lt;/p&gt;&#xA;&lt;p&gt;Explanations in a book like &lt;em&gt;Understanding earth&lt;/em&gt;&lt;sup&gt;1&lt;/sup&gt; is too simple for me (I am not scared by the right amount of math); the chapters in &lt;em&gt;Physics for geologists&lt;/em&gt;&lt;sup&gt;2&lt;/sup&gt; are too succinct; on the other hand a book like &lt;em&gt;Ocean waves in geosciences&lt;/em&gt;&lt;sup&gt;3&lt;/sup&gt; is too deep for me and it lacks waves different from the ocean ones.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Almost all about waves&lt;/em&gt;&lt;sup&gt;4&lt;/sup&gt; is not focused on the Earth Science.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt;GROTZINGER, John; JORDAN, Thomas H.; PRESS, Frank. &lt;em&gt;Understanding earth&lt;/em&gt;. Macmillan, 2010.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;2&lt;/sup&gt;CHAPMAN, Richard E. &lt;em&gt;Physics for geologists&lt;/em&gt;. Taylor &amp;amp; Francis, 2002.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;3&lt;/sup&gt;ARDHUIN, Fabrice. &lt;em&gt;&lt;a href=&quot;https://www.researchgate.net/publication/323280453_Ocean_waves_in_geosciences&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ocean waves in geosciences&lt;/a&gt;&lt;/em&gt;, 2021.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;4&lt;/sup&gt;PIERCE, John R. &lt;em&gt;Almost all about waves.&lt;/em&gt; Cambridge: MIT Press, 1973.&lt;/p&gt;&#xA;" OwnerUserId="7545" LastEditorUserId="7545" LastEditDate="2022-01-20T07:22:09.967" LastActivityDate="2022-12-27T20:50:12.287" Title="Book recommendation on waves" Tags="|oceanography|seismology|waves|reference-request|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="23416" PostTypeId="1" CreationDate="2022-01-20T01:52:06.473" Score="3" ViewCount="59" Body="&lt;p&gt;The Colorado Plateau somehow has avoided all the tectonic activity around it over hundreds of millions of years. Is it just luck, or is there something about that chunk of crust? I have toured the region, and the exposed rocks are mostly horizontal sedimentary strata. On the other hand, the plateau is bounded by mountainous regions, including the Basin and Range, the Uinta mountains, the Rockies, and the volcanic San Juans. Yes, the plateau has been uplifted, but somehow it &lt;strong&gt;appears&lt;/strong&gt; to have done so as a unit and without mountains forming. The relief is due to erosion. Now, I am curious about geology, but I am by no means a geologist, so I may be misusing the terms, but I hope you can understand my question.&lt;/p&gt;&#xA;" OwnerUserId="26208" LastEditorUserId="26208" LastEditDate="2022-01-21T22:15:08.360" LastActivityDate="2022-01-21T22:15:08.360" Title="Why is the Colorado Plateau so stable?" Tags="|geology|plate-tectonics|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23417" PostTypeId="2" ParentId="16335" CreationDate="2022-01-20T02:09:22.347" Score="2" Body="&lt;p&gt;Short answer, there are various estimates, with large uncertainties, ranging from 4 to 7 million km&lt;sup&gt;2&lt;/sup&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Pulling from the &lt;a href=&quot;https://www.le.ac.uk/gl/ads/SiberianTraps/AreaVolume.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt; provided by &lt;a href=&quot;https://earthscience.stackexchange.com/users/6535/keith-mcclary&quot;&gt;Keith McClary&lt;/a&gt; in the comments:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Estimating the original extent of the Traps is difficult, given the&#xA;likely erosion over the last 250 Ma. This is especially important for&#xA;the relatively easily eroded pyroclastic deposits. Whilst preservation&#xA;may have been improved by burial in the West Siberian Basin and&#xA;Yenesei-Khatanga Trough, it is unclear how much tectonic uplift and&#xA;erosion occurred in these basins during the early Triassic, prior to&#xA;burial. Milanovskiy (1976) estimated that the original extent of the&#xA;Traps was about 4x10&lt;sup&gt;6&lt;/sup&gt; km&lt;sup&gt;2&lt;/sup&gt;, but there must be considerable latitude in&#xA;this figure. Masaitis (1983), for example, has suggested that the&#xA;Traps originally extended over a region of ~7 million km&lt;sup&gt;2&lt;/sup&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Masaitis, V.L., 1983. &lt;a href=&quot;https://scholar.google.com/scholar_lookup?title=Permian%20and%20Triassic%20volcanism%20of%20Siberia:%20Problems%20of%20dynamic%20reconstructions.%20Notes%20of%20the%20all-Union%20mineralogical%20society&amp;amp;author=Masaitis,%20V.L.&amp;amp;publication_year=1983&amp;amp;journal=Zap.%20Vseross.%20Miner.%20Obs.&amp;amp;volume=112&amp;amp;pages=412%E2%80%93425&quot; rel=&quot;nofollow noreferrer&quot;&gt;Permian and Triassic volcanism of Siberia: Problems of dynamic reconstructions&lt;/a&gt;. Mineralogicheskogo Obshchestva, 112(4): 412-425.&lt;/p&gt;&#xA;&lt;p&gt;Milanovskiy, Y.Y., 1976. &lt;a href=&quot;https://www.tandfonline.com/doi/abs/10.1080/00206817609471257&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rift zones of the geologic past and their associated formations&lt;/a&gt;. International Geology Review, 18: 619-639.&lt;/p&gt;&#xA;&lt;p&gt;Additionally I have found another estimate Saunders (2009):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The original total area (and volume) of the Siberian flood basalt&#xA;province is difficult to estimate, because a substantial portion is&#xA;covered by thick sedimentary se- quences and because an unknown amount&#xA;has been re- moved by erosion. Taking the limits of the existing out-&#xA;crops as a maximum extent, then we estimate that an area of&#xA;approximately 5×10&lt;sup&gt;6&lt;/sup&gt; km&lt;sup&gt;2&lt;/sup&gt; of Siberia may have been partly covered by&#xA;basalt&lt;a href=&quot;https://www.le.ac.uk/gl/ads/SiberianTraps/AreaVolume.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;. It is unlikely that an accurate figure of area (and volume)&#xA;will ever be known.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Saunders, A., Reichow, M. &lt;a href=&quot;https://www.google.com/url?sa=t&amp;amp;rct=j&amp;amp;q=&amp;amp;esrc=s&amp;amp;source=web&amp;amp;cd=&amp;amp;cad=rja&amp;amp;uact=8&amp;amp;ved=2ahUKEwil7t-_nr_1AhX-lIkEHbARBk44ChAWegQIBxAB&amp;amp;url=http%3A%2F%2Frpdata.caltech.edu%2Fcourses%2FEvolution_GIST_2013%2Ffiles_2013%2Farticles%2FSaunders%2C%2520Reichow%2520-%25202009%2520-%2520The%2520Siberian%2520Traps%2520and%2520the%2520End-Permian%2520mass%2520extinction%2520a%2520critical%2520review.pdf&amp;amp;usg=AOvVaw0IgqrEsXQ_mBxXeFgUHpQU&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Siberian Traps and the End-Permian mass extinction: a critical review&lt;/a&gt;. Chin. Sci. Bull. 54, 20–37 (2009). &lt;a href=&quot;https://doi.org/10.1007/s11434-008-0543-7&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1007/s11434-008-0543-7&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18088" LastActivityDate="2022-01-20T02:09:22.347" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23418" PostTypeId="1" CreationDate="2022-01-20T02:12:08.460" Score="3" ViewCount="107" Body="&lt;p&gt;I have seen this diagram on Wikipedia (link below). It shows that some North American mini-plate boundaries are orogenic bands and some are magmatic arcs, and I think those correspond to continent/continent and continent/ocean crust collisions. But I do not see anything like that at the boundary of the Yavapai/Mazatzal and Wyoming plates. In addition, there are bands marked as passive plate boundaries. How do I interpret these types of boundaries?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wxkQG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wxkQG.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Trans-Hudson_orogeny&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Trans-Hudson_orogeny&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26208" LastActivityDate="2022-01-20T23:18:35.980" Title="Can continental plates collide and fuse together without an orogenic band or magmatic arc or at the junction?" Tags="|geology|plate-tectonics|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23419" PostTypeId="2" ParentId="23413" CreationDate="2022-01-20T16:29:21.863" Score="2" Body="&lt;p&gt;Agricultural sectors are under pressure from food production.&#xA;Population growth, climate change, desertification, water scarcity, soil destroyed by chemicals, monocultures, ...etc. will increase that pressure.&lt;/p&gt;&#xA;&lt;p&gt;That's why I don't think it's a good idea to buy your mobility with an enormous amount of area.&lt;/p&gt;&#xA;&lt;p&gt;Hemp as a construction material has been known for a long time and in the replacement of e.g. aluminum then certainly is useful. Its properties as a dampening and insulating material are also outstanding. It has long been possible to insulate buildings with natural fibers (&amp;amp; carbon storage) and replace environmentally harmful materials such as polystyrene, etc.&lt;/p&gt;&#xA;&lt;p&gt;As a drive technology for aircraft, however, hydrogen produced from offshore wind power, for example, would certainly be the lesser CO&lt;sub&gt;2&lt;/sub&gt;  evil than hemp oil.&lt;/p&gt;&#xA;&lt;p&gt;Nevertheless, there is a way to give the fast-growing hemp a chance and a future. Vertical growing on an industrial scale is nothing else than stacking CO&lt;sub&gt;2&lt;/sub&gt;  absorbing plant growth with artificial lighting. Here you can boost the sequestration of CO&lt;sub&gt;2&lt;/sub&gt; on highly productive, controlled areas by a factor of ~10,000 and use CO&lt;sub&gt;2&lt;/sub&gt;  as an efficiency-enhancing fertilizer.&lt;/p&gt;&#xA;&lt;p&gt;In a cube with a side length of 100m, up to 150,000t CO&lt;sub&gt;2&lt;/sub&gt; /y can be absorbed and thus replace ~100km² of open land area.&#xA;Of course, this also applies to other cultivated plants such as vegetables, salads,...&lt;/p&gt;&#xA;" OwnerUserId="26198" LastEditorUserId="2470" LastEditDate="2022-01-20T16:56:10.973" LastActivityDate="2022-01-20T16:56:10.973" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23420" PostTypeId="2" ParentId="23418" CreationDate="2022-01-20T22:21:40.347" Score="2" Body="&lt;p&gt;The interpretation of most of these interfaces is uncertain.  Most of these plate boundaries are ancient, poorly exposed, have been metamophosed in later orogenies, and have suffered significant amounts of later erosion making it very difficult to say too much about the earlier character of the contact.  Theoretically, you could have a transform fault that would move different terranes next to each other without having a subduction zone between them but I can't think of any example of this happening today.  The closest would be the San Andreas in California.&lt;/p&gt;&#xA;&lt;p&gt;Another problem is that it is hard to take our knowledge of plate tectonics today and extend it back billions of years.  Possibly the earth took a long time to come up with its current convection system and the rules were different initially.  None of the other rocky planets seem to have developed  plate tectonics so we know that the current system on earth is not the only way for a planet to behave.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastEditorUserId="8513" LastEditDate="2022-01-20T22:42:38.150" LastActivityDate="2022-01-20T22:42:38.150" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23421" PostTypeId="2" ParentId="23418" CreationDate="2022-01-20T23:18:35.980" Score="2" Body="&lt;p&gt;You didn't dive deep enough. You're asking about an area on a high-level, generalized map of &lt;a href=&quot;https://en.wikipedia.org/wiki/Basement_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;basement&lt;/a&gt; rock provinces.&lt;/p&gt;&#xA;&lt;p&gt;There were several orogenies at the southern boundary of the Wyoming craton. Between 1800 Ma and 1000 Ma, a series of island arcs accreted to southern Laurentia, building up the pink area on your map.&lt;/p&gt;&#xA;&lt;p&gt;The earliest of these was the &lt;a href=&quot;https://en.wikipedia.org/wiki/Yavapai_orogeny&quot; rel=&quot;nofollow noreferrer&quot;&gt;Yavapai orogeny&lt;/a&gt; between 1800-1700 Ma. It was followed by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mazatzal_orogeny&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mazatzal collision&lt;/a&gt; 1700-1600 Ma.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FdCep.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FdCep.gif&quot; alt=&quot;Yavapai,mazatal orogeny map&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;A 1982 article by Kent C. Condie describes this in more detail. It is &lt;a href=&quot;https://pubs.geoscienceworld.org/gsa/geology/article-abstract/10/1/37/203370/Plate-tectonics-model-for-Proterozoic-continental?redirectedFrom=fulltext&quot; rel=&quot;nofollow noreferrer&quot;&gt;behind a paywall&lt;/a&gt;, but you can see the abstract, which gives the gist.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastActivityDate="2022-01-20T23:18:35.980" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23422" PostTypeId="2" ParentId="23329" CreationDate="2022-01-21T03:33:11.110" Score="2" Body="&lt;p&gt;The typical cycle of volcanic activity is&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Filling of a deep magma chamber&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The deep magma source is controlled by regional tectonics and how it occurs is not well understood in detail.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Movement of the magma to a reservoir at shallow depth&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;This is often accompanied by increased seismic activity, ground levels rising, changes in ground water levels and changes in heat flow.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Extrusion of the magma (now called lava once it erupts) and emptying of the shallow reservoir&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;If the magma comes in contact with ground water the eruption may be explosive.  The release in pressure allows gasses dissolved in the magma to come out of solution (like taking the cap off a seltzer bottle) and blow huge amounts of rock into the sky.  Lava that erupts through dry rocks, or lava without a lot of dissolved gasses, will mostly flow out with some fountaining at the site of the eruption.&lt;/p&gt;&#xA;&lt;p&gt;There may, during the course of the eruption, be further filling of the shallow reservoir and later phases of the eruption sequence.  Looking at the gas being emitted by the volcano is a common way of detecting the introduction of fresh magma at depth.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A winding down phase where the lava solidifies, seismic activity drops, emission of sulpher dioxide goes down, and ground levels return to pre-eruption levels.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;This is interpreted as an exhaustion of the shallow magma reservoir.  Until the links to the deep magma source are closed the volcano may erupt again.  Prediction of such renewed activity decades, even centuries, in the future is not within current capabilities.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2022-01-21T03:33:11.110" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23423" PostTypeId="1" CreationDate="2022-01-21T06:11:53.520" Score="1" ViewCount="41" Body="&lt;p&gt;What emission factor for natural gas boiler should be used for arsenic other than AP-42?&lt;/p&gt;&#xA;&lt;p&gt;I need to to calculate emissions from natural gas boiler. What emission factor for arsenic would be the best to use other than present in AP-42?&lt;/p&gt;&#xA;" OwnerUserId="26249" LastActivityDate="2022-01-21T06:11:53.520" Title="Emission factor for Arsenic" Tags="|air-pollution|environmental-protection|pollution|air-quality|emissions|" AnswerCount="0" CommentCount="2" ClosedDate="2022-01-22T02:34:31.993" ContentLicense="CC BY-SA 4.0" />
  <row Id="23424" PostTypeId="1" AcceptedAnswerId="23425" CreationDate="2022-01-21T16:52:39.067" Score="3" ViewCount="404" Body="&lt;p&gt;We are using weather data to feed building energy models.&lt;/p&gt;&#xA;&lt;p&gt;Historically, we would do that with weather from the closest weather station, which can be far away (up to 100 km, I guess).&lt;/p&gt;&#xA;&lt;p&gt;Recently, we've been investigating the use of ERA5 weather data. This is a fantastic database for us because it provides access to historical data for any given place in the world, for free or close to free.&lt;/p&gt;&#xA;&lt;p&gt;However, I noticed on a few examples an offset with the weather from the weather station. I won't detail this here.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;The point of my question is that I can find ERA5 values but I have no idea of the expected accuracy. In other words, if it says 20°C, does this mean 20°C+-0.2°C, or 20°C+-2°C?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I'd like to tell our engineers how reliable the data I'm providing is.&lt;/p&gt;&#xA;&lt;p&gt;I guess the accuracy is better for recent data since there are more actual data to fit the model. It may depend on many other factors and vary from one physical parameter (temperature, humidity,...) to another.&lt;/p&gt;&#xA;&lt;p&gt;Is there any place where I could find such information in a relatively synthetic way?&lt;/p&gt;&#xA;&lt;p&gt;I've been searching a bit with keywords such as &amp;quot;ERA5&amp;quot; &amp;quot;precision&amp;quot; &amp;quot;accuracy&amp;quot; but found no short answer, if any.&lt;/p&gt;&#xA;" OwnerUserId="26253" LastActivityDate="2022-01-24T21:48:17.750" Title="How accurate is ERA5 weather data?" Tags="|meteorology|era|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23425" PostTypeId="2" ParentId="23424" CreationDate="2022-01-21T17:18:25.803" Score="2" Body="&lt;p&gt;The paper that describes ERA-5 (&lt;a href=&quot;https://doi.org/10.1002/qj.3803&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hersbach et al., 2020&lt;/a&gt;) includes an entire section (Section 7) on the accuracy of the model after data assimilation. As the model assimilates a considerable amount of data from both satellites and in-situ observations, there is always the possibility that differences can occur (e.g., if a specific station was not assimilated, if the difference with the reference fields or other sources of data are large).&lt;/p&gt;&#xA;&lt;p&gt;The difference in temperature is evaluated in a global sense (their Figure 12)&#xA;&lt;a href=&quot;https://i.stack.imgur.com/lrMNv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lrMNv.png&quot; alt=&quot;ERA-5 temperature comparison&quot; /&gt;&lt;/a&gt; Source: &lt;a href=&quot;https://doi.org/10.1002/qj.3803&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hersbach et al., 2020&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Time series of monthly and globally averaged ERA5 ensemble spread from 1979 to 2018 at indicated pressure levels for (a) temperature (&lt;span class=&quot;math-container&quot;&gt;$K$&lt;/span&gt;), (b) zonal wind (&lt;span class=&quot;math-container&quot;&gt;$m s^{−1}$&lt;/span&gt;), (c) ozone (partial pressure in &lt;span class=&quot;math-container&quot;&gt;$mPa$&lt;/span&gt;) and (d) specific humidity (in percent of the 1981 to 2010 mean value at the pressure level in question).&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2022-01-24T21:48:17.750" LastActivityDate="2022-01-24T21:48:17.750" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23427" PostTypeId="2" ParentId="23413" CreationDate="2022-01-21T19:31:09.997" Score="1" Body="&lt;p&gt;Burning crop residue to fly from A to B is no different than burning trees to generate electricity which is almost the same as (the time scales differ) burning coal or oil to generate electricity.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;My comment other site&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;While the first generation of biofuels wreaked havoc on food markets by diverting agriculture food staples into our gas tanks. The second generation wreaked havoc on the environment, by diverting tropical nations into growing palm oils and jatropa to produce in home fuel blends by bulldozing the rainforests. The third generation of biofuels will ruin both and make matters worse. The taxpayer funded debacles of ethanol and biodiesel made from food crops did more harm than good, the hope for finding a substitute for oil had shifted to algae and cellulose. Both of which are scams……plant matter and crops have to be planted, fertilized, harvested, transported, and converted; ALL those stages use energy predominantly using fossil energy.&lt;/p&gt;&#xA;&lt;p&gt;All plant matter uses cellulose in it’s biology, It is too early to say whether or not cellulosic ethanol can ever be produced with a net energy gain as a result – at the moment, it is impossible. We can only hope that scientists will never succeed, because what we do know for sure is that cellulosic ethanol will be an even larger threat than the first generation of biofuels.&lt;/p&gt;&#xA;&lt;p&gt;Cellulosic ethanol is made using inedible parts of the plant…stalks, roots and leaves. It can also be made of non-edible plants, like switchgrass or stuff like wood waste, branches, tree trimmings, conifer needles, shit like that…..sounds like a good approach. However this leaves behind one crucial element; THE SOIL. In nature, the concept of waste does not exist. “WASTE” is food in nature. The so-called “waste” that we plan to transform into fuel, is an essential element to keep the soil productive. Leaves, twigs and stalks, even whole fallen trees are decomposed by underground organisms, or munched on by bugs and invertebrates whose wastes (Poo) feed bacteria and fungi; which turn it into humus that can feed a next generation of plants and other organisms. If you take away this material, the soil will become less and less fertile until all you are left with is a mineral laden soil with no organic material, essentially desert soil. A process offset with more fossil based fertilizers, 2nd failure those fertilizers are good for plant growth but bad for soil health.&lt;/p&gt;&#xA;&lt;p&gt;1st gen biofuels are a reversible, we can decide any time to change our minds and use corn, etc as edibles.&#xA;A similar deployment of cellulosic fuels would destroy our agricultural soils, without any chance to repair them afterwards. We will have mined the soil – a process that is largely irreversible except with 2-3 times more fertilizer than we currently use. When the soil is exhausted, even fertilizers are useless. Just ask a soil scientist…&lt;/p&gt;&#xA;&lt;p&gt;Fuels from plant based oils; Hempoil is same energy density of biodiesel which is 20% inferior to jet fuel which means the plane will have to consume 20% more per mile.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2022-01-21T19:31:09.997" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23429" PostTypeId="1" AcceptedAnswerId="23430" CreationDate="2022-01-22T05:26:49.650" Score="2" ViewCount="119" Body="&lt;p&gt;When I move my pointer around the pin (89.99 N) shown below, Google Earth displays the camera distance, latitude, longitude accordingly.&lt;/p&gt;&#xA;&lt;p&gt;I'd just like to know what does &amp;quot;-4,257m&amp;quot; mean, pointed out by the red arrow.&lt;/p&gt;&#xA;&lt;p&gt;Could someone give me a hint?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PoyOP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PoyOP.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26258" LastEditorUserId="18081" LastEditDate="2022-08-04T08:36:55.887" LastActivityDate="2022-08-04T08:36:55.887" Title="What does &quot;-4,257m&quot; mean in Google Earth?" Tags="|oceanography|bathymetry|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23430" PostTypeId="2" ParentId="23429" CreationDate="2022-01-22T06:26:48.253" Score="5" Body="&lt;p&gt;This is the ocean depth at that point, according to the Google Earth database.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2022-01-22T06:26:48.253" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23432" PostTypeId="1" CreationDate="2022-01-22T11:40:08.507" Score="4" ViewCount="71" Body="&lt;p&gt;I have recently started working on calculating a Geopotential model based on GGM05C. In order to obtain a model as accurate as possible, some corrections must be applied to the normalized Stokes' coefficients provided in GGM05C (Cnm and Snm).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://iers-conventions.obspm.fr/content/chapter6/icc6.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chapter 6 of this IERS note&lt;/a&gt; describes in detail the process. From my understanding, it comprises 5 types of corrections: secular (long-term) corrections, solid Earth tides corrections, ocean tides corrections, solid Earth pole tides corrections and ocean pole tides corrections.&lt;/p&gt;&#xA;&lt;p&gt;I have been able to grasp the idea behind each of these (or so I hope!), except for the case of ocean tides. The main difference I see with all the other corrections (including solid Earth tides) is that the corrections due to each frequency of ocean tides comprises a positive and negative component (both on the Cnm and the Snm components), which, if I understand correctly, must be added before applying the total, resulting correction to the corresponding Cnm/Snm. See for example &lt;a href=&quot;https://iers-conventions.obspm.fr/content/chapter6/icc6.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;equation 6.15 here&lt;/a&gt;. This will then lead to partial cancellation between the 2 (positive and negative) parts. But why is this the case? Both solid Earth tides and ocean tides seem to be an ensemble of periodic effects with different frequencies and amplitudes, but they seem to be treated differently. Why don't we have directly just a single term for each Cnm/Snm, as is the case for solid Earth tides?&lt;/p&gt;&#xA;&lt;p&gt;I am also puzzled by the fact that ocean pole tides do not comprise the same combination of positive and negative terms, and are instead modeled as a single component as can be seen in &lt;a href=&quot;https://iers-conventions.obspm.fr/content/chapter6/icc6.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;equations 6.24 here&lt;/a&gt;, in a very similar way as done for the solid Earth pole tides.&lt;/p&gt;&#xA;" OwnerUserId="26265" LastActivityDate="2022-01-23T01:38:29.207" Title="Why do ocean tides have negative and positive terms in their effects on Stoke's coefficients for calculating geopotential?" Tags="|tides|gravity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23433" PostTypeId="2" ParentId="15885" CreationDate="2022-01-22T13:35:34.760" Score="4" Body="&lt;p&gt;Yes, if you include low frequency pressure changes as would be recorded on a barometer as sound waves.&lt;/p&gt;&#xA;&lt;p&gt;The 2022 &lt;a href=&quot;https://volcano.si.edu/volcano.cfm?vn=243040&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hunga Tonga&lt;/a&gt; &lt;a href=&quot;https://en.wikipedia.org/w/index.php?title=2022_Hunga_Tonga_eruption_and_tsunami&amp;amp;oldid=1067233501&quot; rel=&quot;nofollow noreferrer&quot;&gt;eruption&lt;/a&gt; sent atmospheric pressure waves that were detected multiple times around the Earth.&lt;/p&gt;&#xA;&lt;p&gt;According to the &lt;a href=&quot;https://volcano.si.edu/showreport.cfm?doi=GVP.WVAR20220112-243040&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Volcanism Program&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The sonic boom from this wave was heard at great distances, including&#xA;in Fiji (about 500 km NW), within about two hours in New Zealand&#xA;(1,600-2,000 km), and within about nine hours in Alaska, USA (9,370 km&#xA;NE). The pressure wave was also recorded by infrasound and weather&#xA;instruments worldwide as it circled the Earth, with instruments&#xA;picking up the wave a second time as it arrived from the opposite&#xA;direction.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In a tweet sent by &lt;a href=&quot;https://archive.md/rhT3W&quot; rel=&quot;nofollow noreferrer&quot;&gt;Michael Bunds&lt;/a&gt; you can see in the pressure each time the shock wave passed the weather station in Utah:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/1JsX3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1JsX3.jpg&quot; alt=&quot;Air Pressure at UVU and Passage of Hunga Tonga Eruption Shockwave&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18088" LastActivityDate="2022-01-22T13:35:34.760" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23434" PostTypeId="2" ParentId="23432" CreationDate="2022-01-23T01:38:29.207" Score="3" Body="&lt;p&gt;I don’t know for sure that the feature of ocean tides I am about to describe is the reason, or the only reason, for the difference in treatment you ask about. But it seems likely.&lt;/p&gt;&#xA;&lt;p&gt;Unlike the other corrections, ocean tides have a complicated spatial structure. The &lt;em&gt;forcing&lt;/em&gt; is of course exactly the same as it is for earth tides, but the &lt;em&gt;response&lt;/em&gt; is very different. Whereas earth tides basically distort the entire sphere slightly, the ocean tides behave like waves, excited by astronomical forcing but constrained by the boundaries and bathymetry of ocean basins. The result is, again, complicated: if you look at a world map of the phase of, say, the M2 (lunar semi diurnal) tide, you’ll see many amphidromic points around which high and low tides propagate. It looks nothing like a map of earth tide phase—lines of constant earth tide phase would look a lot like meridians. It does not seem surprising that accounting for the gravitational effects of the more complicated spatial structure of ocean tides would require a more complicated treatment.&lt;/p&gt;&#xA;" OwnerUserId="12008" LastActivityDate="2022-01-23T01:38:29.207" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23435" PostTypeId="1" CreationDate="2022-01-23T03:33:55.637" Score="17" ViewCount="3427" Body="&lt;p&gt;I was intrigued to learn recently of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Paleocene%E2%80%93Eocene_Thermal_Maximum&quot; rel=&quot;noreferrer&quot;&gt;Paleocene–Eocene thermal maximum&lt;/a&gt; from &lt;a href=&quot;https://math.ucr.edu/home/baez/week317.html&quot; rel=&quot;noreferrer&quot;&gt;this blog of John Baez&lt;/a&gt;.  For those who haven't seen, it's the sharp spike labelled &amp;quot;PETM&amp;quot; in this graph (from Wikipedia) of global temperatures over the past 65 million years:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0uUyO.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0uUyO.png&quot; alt=&quot;Global temps over time&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It immediately struck me that this event is somewhat parallel to modern day climate change–an observation which is also mentioned in the Wikipedia article.  Apparently, it is conjectured that the Paleocene–Eocene thermal maximum may have been caused by volcanic eruptions.&lt;/p&gt;&#xA;&lt;p&gt;(In asking the following question, I am not saying that I believe this to be the case (indeed, I find it highly implausible).  I ask simply out of scientific curiosity.)&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Is there any way we could tell whether the Paleocene–Eocene thermal maximum was caused by an ancient race of intelligent life forms, who caused a period of global warming in similar fashion to what humans are doing currently, and subsequently went extinct?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;The answer I expect is along the lines of &amp;quot;No, we can't exclude that for sure.  But we would expect to see some fossil records from such a civilization, which we don't.&amp;quot;  But I would be happy to be surprised in either direction by someone more knowledgeable.  Some food for thought:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/2873&quot;&gt;This answer&lt;/a&gt; indicates that there is uncertainty about what actually caused the PETM.&lt;/li&gt;&#xA;&lt;li&gt;I have heard it said that there are only two things humans have accomplished which will leave a permanent mark on the geological record.  The first is climate change.  The second is leaded gasoline, which will leave an identifiable stratum around the globe.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="26268" LastActivityDate="2022-01-25T01:21:47.423" Title="Could the Paleocene–Eocene thermal maximum have been caused by intelligent life forms?" Tags="|climate-change|paleoclimatology|" AnswerCount="5" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23436" PostTypeId="2" ParentId="23435" CreationDate="2022-01-23T08:48:03.937" Score="22" Body="&lt;p&gt;tl;dr:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;No, we can't exclude that for sure. But we would expect to see some&#xA;fossil records from such a civilization, which we don't.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Yes, pretty much this.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;To elaborate, I would refer to your statement that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;I have heard it said that there are only two things humans have accomplished which will leave a permanent mark on the geological record. The first is climate change. The second is leaded gasoline, which will leave an identifiable stratum around the globe.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is absolutely incorrect. There are so many signatures that our civilisation is leaving at the moment in the geological record, permanently. Some examples:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Mining activities. Assuming your civilisation is extracting resources from the Earth to power their fossil fuel industry, then need to mine the stuff. We are talking about huge holes in the ground. There are no currently known cases of an ore deposit that looks like someone has mined out the valuable stuff millions of years ago, leaving behind a hole (whether currently filled or not) surrounded by lower grade material. What about tailings ponds? Large areas of shallow water (with sediments forming at the bottom), full of stuff that isn't usually found together. This would be very easy to find.&lt;/li&gt;&#xA;&lt;li&gt;Electricity. High voltage power lines. You just don't have very long and thin lines of copper or aluminium forming in nature. Even if they don't remain in their metallic form, copper oxide or carbonate, and aluminium oxide or hydroxide don't form horizontal veins that cut across pretty much everything.&lt;/li&gt;&#xA;&lt;li&gt;Agriculture. The huge amount of fertiliser dumped onto farms, and then washed away in rivers forms very large anomalies of nitrogen and phosphate. Again, something that would stick out like a sore thumb in the geological record.&lt;/li&gt;&#xA;&lt;li&gt;Rare earth elements (lanthanides) and gadolinium. These elements form very distinct concentration distributions in natural rocks and sediments. Humans are using individual elements out of the entire lanthanide group, and this ends up in rivers and then in the ocean. Once the concentration anomalies are out there, they are not going anywhere. We have very sensitive ways to detect even tiny differences of these elements from what they should be in natural systems.&lt;/li&gt;&#xA;&lt;li&gt;Landfills. A whole soup of elements that should not be together. No natural system can form this. They're buried in the ground, and they stay there.&lt;/li&gt;&#xA;&lt;li&gt;Megacities. Tokyo, New York, London, Sydney. Huge amounts of asphalt, concrete, glass, steel, aluminium. Overground and underground. Even if you collapse and erode whatever remains, you will have huge areas covered with former cities, forming rock formation that are otherwise not possible in natural geological processes.&lt;/li&gt;&#xA;&lt;li&gt;Nuclear waste. I reckon there's no need to add anything here - right? Obvious that these things will not form in nature.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;The list goes on and on. Trust me, if there was a civilisation large enough and advanced enough to destroy itself, we would see that very well in the geological record.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2022-01-23T08:48:03.937" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="23438" PostTypeId="1" AcceptedAnswerId="23441" CreationDate="2022-01-23T15:28:27.397" Score="3" ViewCount="237" Body="&lt;p&gt;Does saturation mixing ratio change during adiabatic ascent/descent? I think the mixing ratio (&lt;span class=&quot;math-container&quot;&gt;$r_v = \rho_v/\rho_d$&lt;/span&gt;) is constant as long as no water vapor is condensed out, but saturation mixing ratio always confuses me a little.&lt;/p&gt;&#xA;" OwnerUserId="22353" LastActivityDate="2022-01-24T02:13:22.223" Title="Does saturation mixing ratio change during adiabatic ascent/descent?" Tags="|meteorology|thermodynamics|water-vapour|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23439" PostTypeId="2" ParentId="23435" CreationDate="2022-01-23T19:30:47.487" Score="7" Body="&lt;p&gt;The answer by @Gimelist is a good list of hints we would see, although not all of them are equally convincing or strong, we would expect to see at least some of the signs.&lt;/p&gt;&#xA;&lt;p&gt;The problem with any archaeological sign on Earth is of course that Earth's surface has changed a fair bit in 55 million years. For example, some of the coastlines of that time (where you would expect large cities) are now folded up in the Alps, the Himalayas and other mountain ranges or lie under the Greenland and Antarctica ice sheet, and there's generally been much time for erosion and sedimentation. So we might not have been able to find them as they are buried deep, or they've been changed beyond recognition.&lt;/p&gt;&#xA;&lt;p&gt;So I want to add something totally different: we would likely see some artefacts on the Moon. Of course this would assume that the civilisation developed near Earth space flight, but I don't think this is much of an assumption given that you're looking for an industrial civilisation.&lt;/p&gt;&#xA;&lt;p&gt;As there's virtually no erosion on moon, even items from 55 million years ago would still be there.&lt;/p&gt;&#xA;&lt;p&gt;Now we have &lt;a href=&quot;https://moon.nasa.gov/resources/87/high-resolution-topographic-map-of-the-moon/&quot; rel=&quot;nofollow noreferrer&quot;&gt;maps of the lunar surface with a resolution of about 100 metres&lt;/a&gt;. This would by far not be enough to find the Apollo landers by chance, but our current civilisation is not far away from leaving larger structures on the moon, so it seems to me there is a big probability that previous industrial civilisations would've left something that sticks out like a sore thumb on the lunar maps that we already have.&lt;/p&gt;&#xA;&lt;p&gt;There are plans to build the &lt;a href=&quot;https://en.wikipedia.org/wiki/Lunar_Gateway&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lunar Gateway Station&lt;/a&gt;, a space station in orbit around the moon, by the end of this decade. While that's still not large enough to be found on current maps, you can easily expect a larger station only a few decades away. A station the size of the ISS from 55 million years ago would either still be orbiting the moon or (ore likely) have crashed into it by now, but in either case we should've found the debris. We will probably also build structures on the moon itself in just a few decades, whether research stations on the scale of the Antarctic stations or perhaps some exploratory mining for trace metals (whether that's ever economically viable is a different matter).&lt;/p&gt;&#xA;&lt;p&gt;The point is that Earth's surface has changed so much that likely only very large structures (like megacities) can still be found, but may be deformed so much that we don't recognise them, while on the Moon even comparatively small structures of just a few hundred metres (or much less in some places) would still be very obvious.&lt;/p&gt;&#xA;" OwnerUserId="3163" LastEditorUserId="3163" LastEditDate="2022-01-24T08:03:43.827" LastActivityDate="2022-01-24T08:03:43.827" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23441" PostTypeId="2" ParentId="23438" CreationDate="2022-01-23T22:02:12.603" Score="2" Body="&lt;p&gt;The saturation mixing ratio is not how much water vapor the air has in it... but how much it &lt;em&gt;could&lt;/em&gt; have, based upon the temperature.  Since &lt;strong&gt;adiabatic ascent/descent&lt;/strong&gt; means cooling or heating, &lt;strong&gt;the saturation mixing ratio will change&lt;/strong&gt;.  The actual mixing ratio on the other hand won't change unless you lift the parcel so much that it cools to the dewpoint and beyond and starts condensation.&lt;/p&gt;&#xA;&lt;p&gt;When you're working with a skew-T or such, anytime you see the word &lt;em&gt;saturation&lt;/em&gt;, it signals to refer to the &lt;strong&gt;temperature&lt;/strong&gt; part of the profile (the right/red line) and &lt;strong&gt;not the dew point&lt;/strong&gt; part (the left/green line).&lt;/p&gt;&#xA;&lt;p&gt;Anytime you see that word saturation, it's a different entity... (unless &lt;span class=&quot;math-container&quot;&gt;$T=T_d$&lt;/span&gt;) &lt;em&gt;saturation&lt;/em&gt; mixing ratio is different than mixing ratio, &lt;em&gt;saturation&lt;/em&gt; vapor pressure is different than vapor pressure, etc.  And each are so tied to the temperature/possibility of what can exist at that point and not the dew point/current existing moisture.&lt;/p&gt;&#xA;&lt;p&gt;On a skew T, the saturation mixing ratio is the same shape, up and to the right, along/parallel to the example mixing ratio lines usually given (in dashed light green on this image).  But they aren't the same line (unless &lt;span class=&quot;math-container&quot;&gt;$T = T_d$&lt;/span&gt;):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iDR8X.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iDR8X.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The saturation mixing ratio line starts from the temperature, the regular mixing ratio starts from the dew point.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;I think the mixing ratio (rv=ρv/ρd) is constant as long as no water&#xA;vapor is condensed out, but saturation mixing ratio always confuses me&#xA;a little.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Indeed the (regular) mixing ratio is constant as long as there's no condensation and no outside change to the parcel... for the moisture you stay with the same mixing ratio in ascent (until saturation), such as when calculating the LCL.  But you &lt;a href=&quot;https://en.wikipedia.org/wiki/Lifted_condensation_level&quot; rel=&quot;nofollow noreferrer&quot;&gt;follow the dry adiabat&lt;/a&gt; (lines going up to the left on a skewt like this one) for the temperature for condensation-less ascent (so never use the saturation mixing ratio line, the one coming from just the temperature).&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-01-24T02:13:22.223" LastActivityDate="2022-01-24T02:13:22.223" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23442" PostTypeId="1" AcceptedAnswerId="23451" CreationDate="2022-01-23T22:32:36.357" Score="2" ViewCount="53" Body="&lt;p&gt;I am new to running the WRF-Chem model, so this question maybe a little elementary. I wanted to perform an year-long simulation of certain chemical species for 2019 and for that, is it sufficient to provide the emissions for 2015? I am assuming that the WRF-Chem model will be able to interpolate the emissions to 2019. The reason I am asking this question is because EDGAR/ECLIPSE emissions are available for 2015 and not 2019. Therefore, if the WRF-Chem model does not do the interpolation automatically, do I have to do the interpolation separately and give that as an input to the WRF-Chem model?&lt;/p&gt;&#xA;" OwnerUserId="12660" LastEditorUserId="12660" LastEditDate="2022-01-23T22:46:39.793" LastActivityDate="2022-01-24T22:23:43.817" Title="Can historical emissions data be used for a future WRF-Chem model run?" Tags="|models|climate-models|atmosphere-modelling|wrf|wrf-chem|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23443" PostTypeId="2" ParentId="23435" CreationDate="2022-01-23T23:47:59.080" Score="3" Body="&lt;p&gt;I would add an item to Gimelist's answer, and that is roads.  Our road network is extensive enough that it is implausible that geological processes will completely obliterate all terrain containing roads.  And future processes which expose a geological cross-section, like the erosion of a canyon, can hardly avoid cutting roads.  Crushed rock would presumably fuse or be cemented somewhat over 50M years, but the structure would still be distinctive and anomalous.  So future geologists would see all these little beds of formerly crushed rock, perhaps with the remains of a layer of asphalt on top.  I think that would be pretty hard to miss.&lt;/p&gt;&#xA;" OwnerUserId="26276" LastActivityDate="2022-01-23T23:47:59.080" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23444" PostTypeId="2" ParentId="23435" CreationDate="2022-01-24T03:44:00.597" Score="3" Body="&lt;p&gt;I think you need to ask the inverse:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Could a species significantly change the climate without mining of hydrocarbons, or could they mine hydrocarbons on the scale needed without having a large technological footprint (roads, electrical grid, nuclear-power, etc) that should leave traces?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I would posit that you would be looking for something like a carnivorous civilization that did not need assistance to hunt (no weapons like flints needed to increase take-home calories from hunts), had little interest in increasing prey by farming/feeding them (no fertilizers/farming to increase feed for prey, no herds of fat cows driving out other wildlife), and did not need housing/goods to add protection / comfort - which are going to require resources to be re-distributed.  Of course, once you posit a civilization like that - what would they need the power for?  Mating displays / cultural reasons can only burn up so much gasoline.  And, they have to have seen bad effects happening, and had a reason not to curb their excesses.&lt;/p&gt;&#xA;&lt;p&gt;For avoiding extensive road networks, maybe they used airships/hot air ballons?  I think you'd have to blame a cultural or biological tendency for that (former avian stock that really enjoyed being in the air?), as roads seem far easier to develop.  Cultural imperative to maintain pristine land to grow prey in? (but that would conflict with burning massive amounts of carbon, I think)&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Carbon:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;You don't need an long-distance electrical-grid to burn carbon.  So you might not have evidence from power-lines.&lt;/p&gt;&#xA;&lt;p&gt;A reason they might've avoided/never developed nuclear power, is that they were burning carbon for power instead.  We got into atom-smashing for war and scientific curiosity.&lt;/p&gt;&#xA;&lt;p&gt;How much carbon was locked up in the geological cycle at that point?&lt;/p&gt;&#xA;&lt;p&gt;What evidence would a pumped-out oil reservoir look like after 65mya?  How big were coal-beds at that point?&lt;/p&gt;&#xA;&lt;p&gt;Carbonist manifesto says we've evolved because the geological storage of carbon has gotten out of control (not being cycled thru biosphere), I'm assuming it wasn't such an issue back then.&lt;/p&gt;&#xA;&lt;p&gt;If enough carbon was available in the biosphere, you don't need to mine it.  If you're not mining, you don't need to dig out ore-bodies for metal to make tools/engines to mine.&lt;/p&gt;&#xA;&lt;p&gt;We had extensive surface deposits of high quality ore (Michigan), how new/old are those?&lt;/p&gt;&#xA;&lt;p&gt;Could you have burnt off massive amounts of flora, and/or put lots of methane in the air?  Maybe it was a massive spike in breeding up cow-equivalents (methane producing, and eating all the flora), but over a very small time-span, and none of them got preserved in the fossil record?  We have Lazarus taxa and ghost lineages, and (currently) disappearing breeds of farm animals.  Fossil record is definitely spotty.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Also I specifically want to take issue with some of @Gimelist's answer:&lt;/p&gt;&#xA;&lt;p&gt;If a civilization only developed near seashores or deltas - current humans might not find anything, as most of the former seashore is now under-water.  (Has anyone found a fishing village / midden-heap in Doggerland? - AFAIK; no.  We've found a couple of flints, a skull fragment, an antler point).  We've done very little exploration in these spaces.&lt;/p&gt;&#xA;&lt;p&gt;That said, there are some nice things in the suggestions - which a traceless (near-traceless?) civilization would have to have avoided.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Another thing we'd find with nuclear bombs/power:&lt;/p&gt;&#xA;&lt;p&gt;Radionuclides are also deposited in bones, and can be used to date disasters / bodies born after such incidents (eg: FNPP 2011).  Famous study found: 'that the teeth of children born in St. Louis in 1963 had 50 times the levels of strontium 90 as those of children born in 1950'.&lt;/p&gt;&#xA;&lt;p&gt;I'm interested in whether a thorium-powered civilization would leave traces - it's not able to be weaponized, and can get all nuclear waste to a 300 year decay window.  Of course if you have thorium, why would you burn hydrocarbons?&lt;/p&gt;&#xA;" OwnerUserId="26278" LastEditorUserId="26278" LastEditDate="2022-01-24T22:30:25.377" LastActivityDate="2022-01-24T22:30:25.377" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="23445" PostTypeId="2" ParentId="9451" CreationDate="2022-01-24T06:58:53.427" Score="-1" Body="&lt;p&gt;Water vapours become snow at - 4° C. When it falls on earth, it becomes ice at 0°C, thereby making the atmosphere warmer by 4° during that period. Although other factors are also involved&lt;/p&gt;&#xA;" OwnerUserId="26280" LastActivityDate="2022-01-24T06:58:53.427" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23446" PostTypeId="1" CreationDate="2022-01-24T10:32:23.463" Score="1" ViewCount="97" Body="&lt;p&gt;I've found this rock at the altitude of 2500 meters.&#xA;Is it a plant fossil or trace of water?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/iVftB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iVftB.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26282" LastActivityDate="2022-01-24T10:32:23.463" Title="plant fossil or trace of water?" Tags="|fossils|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23447" PostTypeId="1" CreationDate="2022-01-24T12:01:10.880" Score="16" ViewCount="3700" Body="&lt;p&gt;Why aren't we taking advantage of geothermal heating to produce electricity around the world, instead of burning fossil fuels and using nuclear?&lt;/p&gt;&#xA;&lt;p&gt;Wouldn't it be a lot cheaper than building new power stations that cost billions?&lt;/p&gt;&#xA;&lt;p&gt;If we can drill oil wells, why not wells deep enough for geothermal?&lt;/p&gt;&#xA;&lt;p&gt;Apologies for all the questions, I have the thought in my head and wanted some logical answers.&lt;/p&gt;&#xA;" OwnerUserId="26283" LastEditorUserId="6129" LastEditDate="2022-01-29T00:04:57.183" LastActivityDate="2022-06-30T00:33:18.903" Title="Geothermal instead of fossil and nuclear?" Tags="|geothermal-heat|economic-geology|" AnswerCount="6" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="23448" PostTypeId="1" CreationDate="2022-01-24T16:31:30.293" Score="1" ViewCount="36" Body="&lt;p&gt;Something that's been bugging me for some time now. If, for example, Antarctica started subducting in the direction of the Atlantic Ocean (I'm aware it's not and isn't predicted to), and began subducting the mid-atlantic ridge under itself, what would that do to the divergence of Africa and South America? with the ridge gone, what motion would the plates and especially the continental crust of either continent undergo?&lt;/p&gt;&#xA;&lt;p&gt;Possible bonus question - if a continental plate begins subducting a divergent process underneath itself, what geologic upheaval would that cause for the continent?&lt;/p&gt;&#xA;&lt;p&gt;Thank you for your time.&lt;/p&gt;&#xA;" OwnerUserId="14814" LastActivityDate="2022-01-24T16:31:30.293" Title="Would 2 continental landmasses at a divergent boundary (i.e. Africa and S/A) stop/reverse direction if a continent overrode the original rift?" Tags="|geology|continental-rifting|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23449" PostTypeId="2" ParentId="23447" CreationDate="2022-01-24T16:48:55.440" Score="20" Body="&lt;p&gt;By way of example, the &lt;a href=&quot;https://www.geothermal-energy.org/pdf/IGAstandard/NZGW/2013/Mills_Final.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Habanero geothermal pilot plant&lt;/a&gt; was investigated in Australia from 2003 to 2013. It as a &lt;a href=&quot;https://reneweconomy.com.au/geodynamics-writes-cooper-basin-geothermal-assets-40047/&quot; rel=&quot;nofollow noreferrer&quot;&gt;1 MW plant&lt;/a&gt; in the Cooper Basin, in the central region of Australia.&lt;/p&gt;&#xA;&lt;p&gt;The heat source rock, with a temperature of 264 °C was in excess of 4600 m depth. The project cost AUD 105 million and was ultimately deemed uneconomic. The project involved drilling a number of holes to approximately 4600 m depth, injecting some with vast quantities of water and then collecting the steam generated via another set of holes drilled to 4600 m depth and using the steam to power a turbine to generate electricity.&lt;/p&gt;&#xA;&lt;p&gt;The problems with the project were:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The depth of drilling required - it was deep and expensive.&lt;/li&gt;&#xA;&lt;li&gt;Acquisition of sufficient supplies of water in a arid location.&lt;/li&gt;&#xA;&lt;li&gt;The site location was too remote from locations that might have been&#xA;able to use any generated electricity. The establishment of&#xA;electricity transmission lines would have been very expensive.&lt;/li&gt;&#xA;&lt;li&gt;Having to deal with unfavorable geology, such as fracture zones at&#xA;shallower depths where the injected water would be lost.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;In the picture below, the red areas are the only parts of Australia which has hot rocks to a depth of 5 km that could provide geothermal energy. The area is very small compared to the rest of the continent. Some rocks are deeper.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wZKQy.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wZKQy.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="-1" LastEditDate="2022-01-26T17:49:38.850" LastActivityDate="2022-01-26T17:49:38.850" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23450" PostTypeId="1" CreationDate="2022-01-24T20:53:37.247" Score="1" ViewCount="15" Body="&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What is the zero-offset reflection time from the horizontal seafloor surface at the same depth?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;If I have a point for e.g. at depth = 250m I do know how to solve it, but not sure how to solve this for an horizontal seafloor.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7YrK1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7YrK1.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24983" LastActivityDate="2022-01-24T20:53:37.247" Title="zero-offset reflection time from the horizontal seafloor surface at the same depth" Tags="|sea-floor|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23451" PostTypeId="2" ParentId="23442" CreationDate="2022-01-24T22:23:43.817" Score="1" Body="&lt;p&gt;I will preface this by saying I do not use WRF-Chem myself, and am more familiar with SMOKE/CMAQ using the EPA NEI modeling platforms (not EDGAR).&lt;/p&gt;&#xA;&lt;p&gt;A comprehensive emissions inventory is not prepared for every year, so most modeling projects use the most recently available modeling platform with some project-specific updates.  Depending on the country of interest, you may get different pieces corresponding to different years, regardless if it is stamped with &amp;quot;2015&amp;quot;.  It's up to the modeler to decide whether emissions need to be updated for various categories.  Your project goals should help you identify which emissions are of most importance, and whether they should be updated for your project.&lt;/p&gt;&#xA;&lt;p&gt;In regards to using 2015 for a 2019 scenario, it depends on the pollutants you are studying and the region of interest.  A lot changed over those few years, but you can't update all sectors so you have to prioritize. For instance, ship emissions underwent huge reductions in sulfur emissions during the latter part of that decade.  Vehicle NOx emissions will also have changed, since the fleet would be cleaner (newer vehicles) despite the increase in population.  You could also screen your point source data for any new large facility startups or shutdowns. Point source data are often reported every year by large facilities and you could get more recent information.  Wildfire is very year specific so if you are doing anything PM2.5 related, you should use a 2019-specific fire inventory.&lt;/p&gt;&#xA;&lt;p&gt;Emissions processors that I'm familiar with will allow for the user to input adjustment factors that are sector specific, but it will not interpolate between two different emissions inventory years.  It's easiest to just provide the actual emissions, as it can be quite complicated to implement adjustment factors.  Though, you could also make brute-force adjustments to your emissions intermediate files, before they are merged.  For example, if you expect 2019 NOx vehicle emissions to be 30% less than 2015 values, you could process the vehicle emissions and then run an update script on your gridded emissions file.  It's crude, but it can also be very difficult to create year-specific mobile vehicle emissions.&lt;/p&gt;&#xA;&lt;p&gt;Finally, any good modeling project should undergo a test-run, to identify any major deficiencies (e.g. by matching up with surface monitors of interest).  Emissions updates should be made if anything stands out (e.g. a persistent over-bias in a large region).  Though, keep in mind that the emissions processor will augment annual emissions based on meteorology and temporal profiles, depending on the category.  So, sometimes adjusting annual emissions is not enough to deal with the problem.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2022-01-24T22:23:43.817" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23453" PostTypeId="2" ParentId="23447" CreationDate="2022-01-24T23:44:34.393" Score="16" Body="&lt;p&gt;We certainly couldn't replace all of the world's energy consumption with geothermal;  there literally isn't enough energy coming out of the Earth.&lt;/p&gt;&#xA;&lt;p&gt;The mean thermal energy flow through continental crust from Earth's core is about 65 milliwatts per square meter.  (We will assume that we will not have the technology to built geothermal plants on the ocean floor.)  The land area of Earth is 148,940,000 km&lt;sup&gt;2&lt;/sup&gt;.  Multiplying these two together, we get a net flow of energy of &lt;span class=&quot;math-container&quot;&gt;$9.7 \times 10^{12}$&lt;/span&gt; watts, or 9.7 terawatts.  Over the course of one year, or 8760 hours, this would amount to about &lt;span class=&quot;math-container&quot;&gt;$3.1 \times 10^{20}$&lt;/span&gt; joules, or 290 quadrillion BTUs.  But &lt;a href=&quot;https://www.eia.gov/international/data/world/total-energy/total-energy-consumption&quot; rel=&quot;noreferrer&quot;&gt;the total energy consumption of the world in 2019&lt;/a&gt; was about 600 quadrillion BTUs, which is over double this.&lt;/p&gt;&#xA;&lt;p&gt;Of course, one might argue that we wouldn't want to replace &lt;em&gt;all&lt;/em&gt; energy use with geothermal energy, just electricity generation.  This is a smaller number:  about &lt;a href=&quot;https://www.eia.gov/international/data/world/electricity/electricity-consumption&quot; rel=&quot;noreferrer&quot;&gt;81 quadrillion BTUs.&lt;/a&gt; This is starting to look a bit more feasible, but the problem is that it is impossible — not just &amp;quot;we can't figure out how to do it&amp;quot;, but &amp;quot;there's &lt;a href=&quot;https://en.wikipedia.org/wiki/Second_law_of_thermodynamics&quot; rel=&quot;noreferrer&quot;&gt;a law of physics that forbids it&lt;/a&gt;&amp;quot; — to extract 100% of the thermal energy present in a source as electrical energy.  Typical efficiencies for current commercially viable geothermal electrical plants are around 7–10% instead, and those plants are built in the sorts of places where there are particularly hot rocks at particularly shallow depths.&lt;/p&gt;&#xA;&lt;p&gt;Geothermal is still a useful energy source, of course, in those regions of the world where the geology allows for it to be viable.  But it is unlikely to ever comprise a large part of the world's energy budget.&lt;/p&gt;&#xA;" OwnerUserId="4837" LastActivityDate="2022-01-24T23:44:34.393" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="23454" PostTypeId="2" ParentId="23435" CreationDate="2022-01-25T01:21:47.423" Score="1" Body="&lt;p&gt;The answer is no, it could not have been. Period.&lt;/p&gt;&#xA;&lt;p&gt;Just the one thing, fossil fuel usage, makes this so. Fossil fuels have not been replaced since their making over-to-around 450-400 million years ago. Yet when mankind began using them, even the &amp;quot;low-hanging fruit&amp;quot; was there, ready for the plucking. If a society in your time period had passed through a fossil fuel using stage, and they WOULD have, the low-hanging fruit would have been used, along with much, much more.&lt;/p&gt;&#xA;&lt;p&gt;Yes, tectonic activity could have moved some not-then-low-hanging fruit to be so, but not on the scale we observed when plucking it ourselves. Nor would it replace the used materials.&lt;/p&gt;&#xA;&lt;p&gt;No society would have gone from a few fireplaces straight to nuclear plants powering a world, nor geothermal ones or wind powered ones. And in further (logical) proof of that, how would those three sources have generated the warming on the required scale without massive use on a scale certainly greater than ours (certainly so if not also consuming fossil fuels)? Greater than ours because while ANY energy converted from storage to use then becomes part of the planet's heat load, even without greenhouse effects, though a rising temperature from electricity used from geothermal plants, say, has the effect of... rising temperature due to anything, though without the positive feedback element of adding greenhouse gases.&lt;/p&gt;&#xA;&lt;p&gt;In fact, the use of non-replacing fossil fuels is the reason we need to jump up a level and pretty fast. Without doing so, we will reach a point at which no more are available (doesn't matter if that is the &amp;quot;20 years from now&amp;quot; I've heard since I was 10 for oil supplies, or 2600 AD I keep seeing for natural gas, or 3846 AD:  the day cometh if their use is not replaced).&lt;/p&gt;&#xA;&lt;p&gt;When that happens, a very harsh situation will develop, akin to hunter-gathers feasting on a positive feedback loop of grain and seeing their populations grow, then the grain is gone, largely, for a generation or six, and their populations fall drastically. Aided probably by fighting along the way, but also just by fewer children being supportable.&lt;/p&gt;&#xA;&lt;p&gt;As we fall from modernity, our chance as a species will then be lost forever. Forever. Because probably no one will ever make the jump from burning wood and replacing it with wind power then developing nuclear technology (or even geothermal). So we won't &amp;quot;rise&amp;quot; again, but rather just fall away, though probably getting our 5-15 million more years before the species dies out.&lt;/p&gt;&#xA;&lt;p&gt;If there had been such a civilization as posited in the question, we'd've run up against a wall (in Europe) hundreds of years ago when we began to actually see deforestation with no little story for ourselves that it was to increase farmland.&lt;/p&gt;&#xA;&lt;p&gt;So WE wouldn't exist as we clearly actually do. Ergo, there was NO such civilization then, or 10,000 years BC, or 20,000 years BC, or whatever quack garbage is spewed forth by people on the fringe. When Edgar Cayce is your main scientist, you have problems.&lt;/p&gt;&#xA;&lt;p&gt;So no, such a civilization did not exist. They did not fall from grace, nor did they reach to the stars and meet Admiral Janeway. If they had, we would not be here, and we are.&lt;/p&gt;&#xA;&lt;p&gt;It is also a sobering thing to think about instead of worrying about our beachfront homes in Colorado and South Dakota being overrun by water someday. Decent chance the lack of alien contact (via radio, not starships) could be due to this degeneration  occurring on other planets as well, if they even had a suitably long period of time between trees, bushes, plants, ferns, etc. and the evolution of bacteria that could break down their fibers. Planets with user a species that (like us) did not seem on a path to solving the energy source jump (fusion, really) before they started down the energy/civilization slope and reached a point at which they could never have another chance. Planets that (hopefully, unlike us!) that did not see the user species solve, or even seriously consider the problem itself, and tanked, and so never reached (via radio, not starships... it will NEVER be starships... we are in this system and alone, forever:  well, as long as we last) any other star's planetary system's people. No more paradox, eh?&lt;/p&gt;&#xA;&lt;p&gt;No, it could not have given the evidence of us and the ease with which incredible amounts of oil, coal, and gas were easy to obtain in the not so long ago past. Some amount, even moderate amounts could have been tectonic forces at work, but even today, some of all of them are still very easy to obtain. So no.&lt;/p&gt;&#xA;" OwnerUserId="26292" LastActivityDate="2022-01-25T01:21:47.423" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23455" PostTypeId="2" ParentId="23429" CreationDate="2022-01-25T03:47:14.497" Score="0" Body="&lt;p&gt;This is the elevation of the ocean floor, which is the negative of the depth.&lt;/p&gt;&#xA;" OwnerUserId="6535" LastActivityDate="2022-01-25T03:47:14.497" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23456" PostTypeId="2" ParentId="23429" CreationDate="2022-01-25T11:07:41.113" Score="3" Body="&lt;p&gt;Google earth uses the EGM96 geoid as it's reference for altitude/depth. EGM96 is a model of the ocean surface that takes into account the fact that the earth isn't a sphere, and some account of regional variation in gravity. So the number is the difference between the sea floor and the ocean surface (geoid) at that point. WGS84, the system used by GPS, has a similar model, but less accuracy as it is older.&lt;/p&gt;&#xA;&lt;p&gt;Only a small percentage of the oceans have been surveyed in detail so you shouldn't read too much into the precise number - it will be an estimate from, in mid ocean, what might be low resolution bathymetry.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2022-01-25T11:07:41.113" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23457" PostTypeId="1" CreationDate="2022-01-25T12:43:34.440" Score="1" ViewCount="28" Body="&lt;p&gt;Fossils are bacteria colonies sometimes, a bone can expand with fluid. This is pretty common sense and I understand it.&lt;/p&gt;&#xA;&lt;p&gt;But what is taphonomic expansion? Does it mean a fossil can be bigger than the original organism, just like if you let rice soak, it gets bigger?&lt;/p&gt;&#xA;" OwnerUserId="6062" LastEditorDisplayName="user20559" LastEditDate="2022-01-25T12:45:54.023" LastActivityDate="2022-01-25T12:45:54.023" Title="What is taphonomic expansion?" Tags="|paleontology|taphonomy|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23458" PostTypeId="1" CreationDate="2022-01-25T14:34:01.057" Score="3" ViewCount="210" Body="&lt;p&gt;The question is quite simple, does there exist a meridian on Earth that only passes over water, with the exception of continental Antarctica of course.&lt;/p&gt;&#xA;&lt;p&gt;From eyeballing a world map it seems somewhere around 168 °W (192 °E) is the most likely candidate but it might pass through Umnak island.&lt;/p&gt;&#xA;&lt;p&gt;Is there a sea-only meridian?&lt;/p&gt;&#xA;" OwnerUserId="26299" LastEditorUserId="2470" LastEditDate="2022-01-25T17:34:41.250" LastActivityDate="2022-01-30T11:39:17.363" Title="Is there a meridian that only passes through water (excl. continental Antarctica)?" Tags="|geography|coordinate-system|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23459" PostTypeId="2" ParentId="23447" CreationDate="2022-01-25T19:44:31.813" Score="4" Body="&lt;p&gt;Asking whether we can replace the major energy sources we are using today today with one single source is a flawed question. It is obvious that there is not one single solution and anything that can be part of the energy mix should be taken into account. The all or nothing approach like the one in the answer by @Michael Seifert is the classic argument used to criticise all the possible solutions by those who don't want to invest anything on those solutions. If you take separately hydroelectric, geothermal, wind, biomass and other renewables none of them is the magic wand that would solve the energy problem. But also nuclear and fossil fuels are by themselves insufficient, they always worked as parts of the energy mix.&lt;/p&gt;&#xA;&lt;p&gt;I don't know how much geothermal could actually contribute, but I know that it deserves a lot more attention. The example cited by @Fred shows that it is not a solution available anywhere, but on the other hand it seems a project designed to fail. They decided to evaluate cost returns by geothermal under the most difficult conditions. It is true that the high temperature they found guarantees a better efficiency, but it came at a cost because the cost of drilling a well increases exponentially with the depth. So a lower depth, would have meant a lower efficiency, but much lower startup cost and geothermal projects are capital intensive, the running cost is usually a small part of the total cost. I wrote usually because the water actually matters, choosing a desert for the first project doesn't seem a great idea. BTW the deepest wells of the longest running geothermal project in &lt;a href=&quot;https://en.wikipedia.org/wiki/Larderello&quot; rel=&quot;nofollow noreferrer&quot;&gt;Larderello&lt;/a&gt; are not much deeper than 3000 meters.&lt;/p&gt;&#xA;&lt;p&gt;So, even though we don't have a lot of places with the right temperature at low depths and enough water available for big projects in the style of Iceland there are many places suitable for small scale projects with small efficiency, but also smaller initial investment. Furthermore there are even more places suitable for &lt;a href=&quot;https://en.wikipedia.org/wiki/Geothermal_heating&quot; rel=&quot;nofollow noreferrer&quot;&gt;direct heating&lt;/a&gt;. Simply expanding the use of geothermal energy for district heating around the world could cover a non negligible chunk of our energy demand, just forget the all or nothing approach, magic wands just don't exist.&lt;/p&gt;&#xA;" OwnerUserId="18774" LastEditorUserId="18774" LastEditDate="2022-01-25T20:13:48.300" LastActivityDate="2022-01-25T20:13:48.300" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23460" PostTypeId="2" ParentId="23458" CreationDate="2022-01-25T22:39:18.953" Score="4" Body="&lt;p&gt;The answer is no.&lt;/p&gt;&#xA;&lt;p&gt;In the Atlantic Ocean any meridian that would avoid South America and Africa would pass over Greenland.&lt;/p&gt;&#xA;&lt;p&gt;In the Pacific Ocean, St Lawrence Island, just to the south of the Bering Strait is a major obstacle. This forces any likely meridian to be to the east of the island - as you state around 168° W (192° E). The easternmost point of St Lawrence Island is at 168° 41' 17&amp;quot; W.&lt;/p&gt;&#xA;&lt;p&gt;To the north of St Lawrence Island is a tiny spec of an island called King Island. It's westernmost point is 168° 05' 53&amp;quot; W. That's a difference of 35' 24&amp;quot; in longitude. Which isn't much room.&lt;/p&gt;&#xA;&lt;p&gt;As you indicate, that zone lies in in the central region of the Aleutian island of Umnak Island, which extends from 169° 06' 48&amp;quot; W to 167° 47' 07&amp;quot; W.&lt;/p&gt;&#xA;&lt;p&gt;Johnson Atoll, at around 169° W is close to that that Meridian zone, as is Niue. South of Umnak Island, within that meridian zone there is no land above sea level, but there are geological features such a sea mounts, particularly the line of mounts between Hawaii and Midway Atoll.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2022-01-30T11:39:17.363" LastActivityDate="2022-01-30T11:39:17.363" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23461" PostTypeId="2" ParentId="18596" CreationDate="2022-01-26T00:52:38.650" Score="5" Body="&lt;p&gt;Assuming an island is defined as a body of land surrounded by water, then the largest island in the world is the Europe and Asia land mass (with Africa included if the Suez canal is not regarded as a body of water because it is man made).&lt;/p&gt;&#xA;" OwnerUserId="26305" LastEditorUserId="2470" LastEditDate="2022-01-26T01:45:55.633" LastActivityDate="2022-01-26T01:45:55.633" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23463" PostTypeId="2" ParentId="18117" CreationDate="2022-01-26T01:38:13.650" Score="0" Body="&lt;p&gt;An article about &lt;a href=&quot;https://www.nature.com/articles/s41598-021-04193-9&quot; rel=&quot;nofollow noreferrer&quot;&gt;Land Subsidence due to groundwater over extraction&lt;/a&gt; in Delhi National Capital Region of India. They have used PSInSAR for deformation estimation and compared with groundwater extraction.&#xA;&lt;a href=&quot;https://www.nature.com/articles/s41598-021-04193-9&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/s41598-021-04193-9&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26306" LastActivityDate="2022-01-26T01:38:13.650" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23466" PostTypeId="2" ParentId="19391" CreationDate="2022-01-26T13:39:12.517" Score="2" Body="&lt;p&gt;Let us suppose, that the pollutant distributes in the lower 10 km&#xA;layer (H), and its concentrations (C) are equal on each altitude for more simple calculations. [mol/m&lt;sup&gt;2&lt;/sup&gt;] must be converted to [mg/m&lt;sup&gt;3&lt;/sup&gt;] for comparison with national threshold standards. Therefore, the near-ground value in [mg/m&lt;sup&gt;3&lt;/sup&gt;] is:&lt;/p&gt;&#xA;&lt;p&gt;C = (C&lt;sub&gt;col&lt;/sub&gt;/H) * M * A,&lt;/p&gt;&#xA;&lt;p&gt;where,&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;C&lt;sub&gt;col&lt;/sub&gt; is the pollutant column content [mol/m&lt;sup&gt;2&lt;/sup&gt;],&lt;/li&gt;&#xA;&lt;li&gt;M is the molar mass [g/mol],&lt;/li&gt;&#xA;&lt;li&gt;A is a constant, equals to 1000, for conversion from [g/m&lt;sup&gt;3&lt;/sup&gt;] to [mg/m&lt;sup&gt;3&lt;/sup&gt;].&lt;/li&gt;&#xA;&lt;li&gt;H is expressed in [m].&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;REF:&#xA;DOI:10.28974/idojaras.2021.2.6&lt;/p&gt;&#xA;" OwnerUserId="26314" LastEditorUserId="2470" LastEditDate="2022-01-26T22:38:14.387" LastActivityDate="2022-01-26T22:38:14.387" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23467" PostTypeId="2" ParentId="23447" CreationDate="2022-01-26T16:18:39.210" Score="2" Body="&lt;p&gt;Only a few regions where hot water is available near the surface (e.g. Iceland) are suitable for producing electricity.&#xA;But in order to store thermal energy and thus save or replace the consumption of fossil, but also renewable energies and green electricity, underground water volumes are ideal because 1m³ of water with a temperature difference of&#xA;ΔT = 40°C (e.g. 15°C - 55°C) can store about 47 kWh of thermal energy.&lt;/p&gt;&#xA;&lt;p&gt;Since the heat flow from the earth's core towards the surface is rather poor (~ 0.09W/m²), I suggest using the summer's radiant energy from the sun (up to ~ 1000W/m²) to use this unbeatably cheap energy storage. In order to absorb this heat mainly in summer, solar modules are a widespread, efficient tool today - water-cooled PV-T modules (electricity &amp;amp; heat production) would be even better, which, for whatever reason, are unfortunately still a niche product.&lt;/p&gt;&#xA;&lt;p&gt;The power output, but also the longevity of almost all PV modules increases by ~0.4%/°C cooling, while the overall efficiency of a module / area can quadruple from ~20% to ~80%.&lt;/p&gt;&#xA;&lt;p&gt;So the simplest and most logical solution for a large part of the energy sector would be to harvest summer heat and store it seasonally for use in winter. With the right heat pump, this heat store turns into an ice store in winter, which in turn can be used for cooling in summer.&lt;/p&gt;&#xA;&lt;p&gt;There are countless caverns, former coal mines or other underground mines worldwide that are suitable as large-volume energy storage in the form of heat/cold storage, pumped storage or compressed air storage - ideally, the combination of the different types of use increases the overall efficiency of such investments.&lt;/p&gt;&#xA;&lt;p&gt;Since we not only have to reckon with increased water shortages due to climate change, but also with heavy rain and flooding (drought &amp;amp; flood), such underground water reservoirs can also help to get these events under control much better.&lt;/p&gt;&#xA;" OwnerUserId="26198" LastEditorUserId="2470" LastEditDate="2022-02-05T22:12:34.510" LastActivityDate="2022-02-05T22:12:34.510" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23468" PostTypeId="1" CreationDate="2022-01-27T10:53:42.197" Score="4" ViewCount="35" Body="&lt;p&gt;Allied to the question: &lt;em&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/4728/why-is-relative-sea-level-falling-in-hudson-bay&quot;&gt;Why is relative sea-level falling in Hudson Bay?&lt;/a&gt;&lt;/em&gt;, where the surviving answers mention post glacial rebound.&lt;/p&gt;&#xA;&lt;p&gt;Is seismicity associated with post glacial rebound and if so what is the frequency of quakes (number of quakes per time period) and their magnitudes?&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-01-27T10:53:42.197" Title="Seismicity associated with post glacial rebound" Tags="|seismology|seismic|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23470" PostTypeId="2" ParentId="23458" CreationDate="2022-01-28T14:14:47.427" Score="6" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Is there a meridian that only passes through water (excl. continental Antarctica)?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;No.&lt;/p&gt;&#xA;&lt;p&gt;Note: All longitude spans in this answer are from easternmost point to westernmost point.&lt;/p&gt;&#xA;&lt;p&gt;The mainland of Africa+Eurasia blocks everything from 169°39'07&amp;quot; W (Cape Deznhev in Russia) to 17°32'08&amp;quot; W (Dakar, Senegal). The mainland of the Americas blocks everything from 34°47'35&amp;quot; W (Santa Rita, Paraíba, Brazil) to 168°07'12&amp;quot; W (Cape Prince of Wales, Alaska, U.S.). All that is left are two gaps, one in the Atlantic Ocean between 17°32'08&amp;quot; W and 34°47'35&amp;quot; W, and another in the Bering Strait between 168°07'12&amp;quot; W and 169°39'07&amp;quot; W.&lt;/p&gt;&#xA;&lt;p&gt;This does not yet account for islands. Three islands suffice to close those gaps. Greenland, which spans from 11°21'36&amp;quot; W to 73°47'35&amp;quot; W, closes the gap in the Atlantic, while Umnak (which spans from 167°47'00&amp;quot; W to 169°07'08&amp;quot; W) and St. Lawrence Island (which spans from 168°41'17&amp;quot; W to 171°51'00&amp;quot; W) together cover in the gap in the Pacific. Note that the westernmost point of Unmak is to the west of the easternmost point of St. Lawrence Island, so there is no gap between these two islands.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2022-01-30T10:25:16.787" LastActivityDate="2022-01-30T10:25:16.787" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23471" PostTypeId="1" CreationDate="2022-01-28T21:13:18.753" Score="13" ViewCount="2943" Body="&lt;p&gt;&lt;em&gt;First of all, I want to add the disclaimer that I am not a climate sceptic or anything. I honestly want to understand this phenomenon. Hopefully, someone can also go into the details as I do have somewhat of a statistical background.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;According to the Guardian article, &lt;a href=&quot;https://www.theguardian.com/environment/2022/jan/27/word-salad-of-nonsense-scientists-denounce-jordan-petersons-comments-on-climate-models&quot; rel=&quot;noreferrer&quot;&gt;&amp;quot;‘Word salad of nonsense’: scientists denounce Jordan Peterson’s comments on climate models&amp;quot;&lt;/a&gt;, Jordan Peterson made the claim that climate models couldn't be relied on because errors compound as you forecast further into the future:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;[Peterson] said: &amp;quot;Another problem that bedevils climate modelling, too, which is that as you stretch out the models across time, the errors increase radically. And so maybe you can predict out a week or three weeks or a month or a year, but the farther out you predict, the more your model is in error.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;And that’s a huge problem when you’re trying to model over 100 years because the errors compound just like interest.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Scientists have responded saying this understanding is wrong:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Dr Sarah Perkins-Kirkpatrick, a climate scientist at the University of New South Wales Canberra, said Peterson’s description of how climate models work was fundamentally wrong. While weather forecasts do become less accurate the further out they go, this was a different process to climate modelling.&#xA;[...]&lt;/p&gt;&#xA;&lt;p&gt;Prof Steve Sherwood, of the Climate Change Research Centre at the University of New South Wales, said Peterson was “making the ancient climate sceptic error of mixing up weather and climate”.&lt;/p&gt;&#xA;&lt;p&gt;“Anyone who has taken an introductory course in climate or atmospheric science would spot this problem,” he said. “Errors in a weather forecast indeed accumulate such that after a couple of weeks the forecast is useless.”&lt;/p&gt;&#xA;&lt;p&gt;But with climate, Sherwood said, the models work differently to project how the climate will respond to different factors, such as higher levels of CO2.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;So why is this the case? Why don't errors accumulate?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="26331" LastEditorUserId="7741" LastEditDate="2022-01-28T23:04:39.620" LastActivityDate="2022-02-03T05:12:33.777" Title="Why don't errors accumulate in climate models when the time horizon increases?" Tags="|climate-change|climate|climate-models|" AnswerCount="7" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="23472" PostTypeId="2" ParentId="23264" CreationDate="2022-01-28T21:40:30.923" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;I imagine it is difficult for the ocean to freeze solid due to the low freezing point of saltwater and the insulating effect of the formation of sea ice over the cool but still liquid ocean water.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It is difficult and It doesn't happen often. The entire earth was frozen before but that was because most landmasses were at the equator and weathering was very fast.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;Temperatures on a snowball Earth are estimated to have reached minus 58 degrees Fahrenheit (minus 50 degrees Celsius). As the ice spread, more heat was reflected back into space rather than absorbed by the planet, dropping temperatures down in a runaway effect that sped the formation of ice.&amp;quot; (Space.com)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Certainly for the ocean to freeze entirely, I think first the entire ocean would have to cool to near freezing even in the tropics.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This technically really hasn't ever happened before in geological history, due to the sun and heat influx from volcanos. (Considering there was landmass in the equator). If the ice somehow created a runaway affect, this would mean that the ice reflected back more heat/sunlight than it received. P.S: If your not taking land into account then the oceans would for sure freeze at some point (not now though) :)&lt;/p&gt;&#xA;&lt;p&gt;Now for the grand question: (Drumroll)&lt;/p&gt;&#xA;&lt;h1&gt;How cold would the Earth have to be for the oceans to freeze entirely?&lt;/h1&gt;&#xA;&lt;p&gt;So obviously there weren't any thermometers back in the day so we can only estimate. It's estimated it was minus 58 degrees Fahrenheit (minus 50 degrees Celsius) was the temperature for snowball earth (Plus a major redistribution of continents.)&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;So that wraps up our answer for today, please let me know if my answer is not in line with your question.&lt;/p&gt;&#xA;" OwnerUserId="21926" LastActivityDate="2022-01-28T21:40:30.923" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23473" PostTypeId="2" ParentId="23471" CreationDate="2022-01-28T21:55:50.293" Score="17" Body="&lt;p&gt;&lt;strong&gt;Error does accumulate in climate models out into the future -- that's why the forecasts include a range of possible results, that gets wider the further into the future you look.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;See, for instance, this figure from the IPCC's Fifth Assessment Report, &lt;a href=&quot;https://ar5-syr.ipcc.ch/topic_summary.php&quot; rel=&quot;noreferrer&quot;&gt;Summary for Policy Makers&lt;/a&gt; (SPM):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qEf05.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qEf05.png&quot; alt=&quot;Global average surface temperature change (a) and global mean sea level rise&#xA;(b) from 2006 to 2100 as determined by multi-model simulations.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Each RCP is a pathway, depending on how much carbon we emit. &lt;a href=&quot;https://en.wikipedia.org/wiki/Representative_Concentration_Pathway&quot; rel=&quot;noreferrer&quot;&gt;Per Wikipedia&lt;/a&gt;, the number represents the expected radiative forcing, in watts per meter squared (W/m&lt;sup&gt;2&lt;/sup&gt;) that can be expected in the year 2100.&lt;/p&gt;&#xA;&lt;p&gt;The SPM explains what each RCP represents:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Representative Concentration Pathways, (RCPs) which are used for making projections based on these factors, describe four different 21st century pathways of GHG emissions and atmospheric concentrations, air pollutant emissions and land-use. The RCPs include a stringent mitigation scenario (RCP2.6), two intermediate scenarios (RCP4.5 and RCP6.0) and one scenario with very high GHG emissions (RCP8.5). Scenarios without additional efforts to constrain emissions ('baseline scenarios') lead to pathways ranging between RCP6.0 and RCP8.5 (Figure SPM.5.a). RCP2.6 is representative of a scenario that aims to keep global warming likely below 2°C above pre-industrial temperatures.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So if we stay on our current path, we can expect warming of 3 to 5.5 degrees, with sea level rise of 0.5 to 1 m.&lt;/p&gt;&#xA;" OwnerUserId="7741" LastActivityDate="2022-01-28T21:55:50.293" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23474" PostTypeId="2" ParentId="23471" CreationDate="2022-01-29T10:30:49.360" Score="10" Body="&lt;p&gt;There is a huge confusion between errors in weather forecasting and climate prediction.&lt;/p&gt;&#xA;&lt;p&gt;While weather predictability is fundamentally limited to a few weeks, in climate modelling we are interested in the statistical properties of the modelled weather, even if the modelled weather for a given day in 10 years from now is completely random.&lt;/p&gt;&#xA;&lt;p&gt;The climate system is extremely complex but perhaps it is instructive to compare this with simple fluid dynamics. In a turbulent pipe flow we cannot predict where each small vortex will be. If we have an initial condition, we can only accurately follow it for a very limited time even in very accurate direct numerical simulations. But it does not matter, because the statistical properties of such a turbulent flow can be captured very accurately by such simulations.&lt;/p&gt;&#xA;" OwnerUserId="15200" LastEditorUserId="2958" LastEditDate="2022-01-29T21:48:26.667" LastActivityDate="2022-01-29T21:48:26.667" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="23475" PostTypeId="2" ParentId="23471" CreationDate="2022-01-29T11:10:50.520" Score="5" Body="&lt;p&gt;Our uncertainty in climate prediction increases over time, but not because of accumulated errors in the way that (for example) compound interest accumulates.&lt;/p&gt;&#xA;&lt;p&gt;In compound interest each calculation relies on the one before it. If you tried to build on a weather forecast in this way the errors very quickly become enormous, since a weather forecast relies on making short-term but (hopefully) high-accuracy predictions based on relatively small-scale things like &lt;a href=&quot;https://www.metoffice.gov.uk/weather/learn-about/how-forecasts-are-made/observations/observations&quot; rel=&quot;noreferrer&quot;&gt;wind speed and surface temperature&lt;/a&gt;. The trouble arises if we then try to use those forecasted values as the input for the next day's calculations – our errors will quickly snowball because the uncertainty in our forecasts is pretty big compared to the measurements. Because of this, we don't accumulate predictions as the timescales increase.&lt;/p&gt;&#xA;&lt;p&gt;Climate forecasts are made across much longer periods, with larger-scale observations (we're talking &lt;a href=&quot;https://www.theccc.org.uk/what-is-climate-change/measuring-a-warming-world-2/&quot; rel=&quot;noreferrer&quot;&gt;decades, centuries or more&lt;/a&gt;), and different statistical models, but have nothing to do with what the weather is now, or what we think it will be tomorrow or the day after. The fact it's currently 9ºC and a bit cloudy is as irrelevant to climate forecasts as the fact that 1904 was the coldest year on record is to if it's going to rain tomorrow.&lt;/p&gt;&#xA;&lt;p&gt;There are actually a whole bunch of forecasts which use progressively longer-term and larger-scale data, from the hyperlocal (&amp;quot;it's probably going to rain in your neighbourhood in the next five minutes&amp;quot;) up to the geological (&amp;quot;there's probably going to be an ice age on the Earth in the next few thousand years&amp;quot;). You can find a 'long range forecast' for most places (&lt;a href=&quot;https://www.metoffice.gov.uk/weather/long-range-forecast&quot; rel=&quot;noreferrer&quot;&gt;here's the one for the UK&lt;/a&gt;) which gives an example of an intermediate, looking a month or so out at what the weather is likely to be but without specific predictions.&lt;/p&gt;&#xA;" OwnerUserId="26332" LastActivityDate="2022-01-29T11:10:50.520" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23476" PostTypeId="2" ParentId="23309" CreationDate="2022-01-29T15:19:05.900" Score="-2" Body="&lt;p&gt;Climate change will increase the size of stalled high-pressure weather systems called &amp;quot;blocking events&amp;quot; that have already produced some of the 21st century's deadliest heat waves, according to a Rice University study.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedaily.com/releases/2019/11/191113075107.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedaily.com/releases/2019/11/191113075107.htm&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Atmospheric blocking events are middle-latitude, high-pressure systems that stay in place for days or even weeks. Depending upon when and where they develop, blocking events can cause droughts or downpours and heat waves or cold spells.&lt;/p&gt;&#xA;" OwnerUserId="26198" LastActivityDate="2022-01-29T15:19:05.900" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23478" PostTypeId="1" CreationDate="2022-01-31T00:44:22.783" Score="5" ViewCount="70" Body="&lt;p&gt;Is there any link with the subduction of the Farallon Plate and the associated spreading center?&lt;/p&gt;&#xA;" OwnerUserId="26208" LastEditorUserId="725" LastEditDate="2022-02-02T07:20:39.170" LastActivityDate="2022-02-02T07:20:39.170" Title="What is causing the crustal extension exhibited by the Basin and Range province in western North America?" Tags="|geology|plate-tectonics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23479" PostTypeId="2" ParentId="16651" CreationDate="2022-01-31T09:31:32.310" Score="2" Body="&lt;p&gt;You can get detailed information on the &lt;a href=&quot;https://www.bas.ac.uk/project/brunt-ice-shelf-movement/&quot; rel=&quot;nofollow noreferrer&quot;&gt;British Antarctic Survey's&lt;/a&gt; website. BAS have installed 15 GPS instruments and also monitor the chasm with telemetered radar that profiles the area around the chasm. Chasms are cracks in the ice shelf that penetrate through the shelf to the sea.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2022-01-31T09:31:32.310" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23480" PostTypeId="1" AcceptedAnswerId="23486" CreationDate="2022-01-31T10:28:37.320" Score="3" ViewCount="210" Body="&lt;p&gt;I am currently using the GGM05C Stokes' coefficients to reconstruct the gradient of gravity potential of Earth.&lt;/p&gt;&#xA;&lt;p&gt;I have found an expression for said gradient in spherical coordinates in &lt;a href=&quot;http://icgem.gfz-potsdam.de/str-0902-revised.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this technical report by the ICGEM&lt;/a&gt;. In particular, equation 122 on page 23 shows the partial derivatives of the gravity potential &lt;span class=&quot;math-container&quot;&gt;$W$&lt;/span&gt; with respect to the three spherical coordinates parameters &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; (distance to center), &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt; (longitude) and &lt;span class=&quot;math-container&quot;&gt;$\varphi$&lt;/span&gt; (geocentric latitude).&lt;/p&gt;&#xA;&lt;p&gt;These equations involve the use of associated Legendre functions &lt;span class=&quot;math-container&quot;&gt;$P_{lm}$&lt;/span&gt;, which are a function of the latitude &lt;span class=&quot;math-container&quot;&gt;$\varphi$&lt;/span&gt;. I understand then that, when performing the partial derivatives with respect to &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\varphi$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt;, the Legendre functions remain unaltered in the derivatives with respect to &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt;, since the Legendre functions are not a function of either &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; or &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt;. However, since they are a function of the latitude &lt;span class=&quot;math-container&quot;&gt;$\varphi$&lt;/span&gt;, when we calculate &lt;span class=&quot;math-container&quot;&gt;$\dfrac{\partial W}{\partial \varphi}$&lt;/span&gt;, we need to derive the associated Legendre functions, obtaining the following expression, as indicated in equation 122 of the linked document:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\dfrac{\partial W}{\partial \varphi} = \frac{GM}{r}\sum_{\mathscr{l}=0}^{\mathscr{l}_{max}}\left(\frac{R}{r}\right)^\mathscr{l}\sum_{m=0}^{\mathscr{l}}\dfrac{\partial P_{\mathscr{l}m}(sin\ \varphi)}{\partial \varphi}\left(C_{\mathscr{l}m}^Wcos(m\lambda)+S_{\mathscr{l}m}^Wsin(m\lambda)\right)&#xA;$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, following the chain rule, shouldn't this derivative also include a multiplication by &lt;span class=&quot;math-container&quot;&gt;$cos\ \varphi$&lt;/span&gt;, since that is the derivative of the &lt;span class=&quot;math-container&quot;&gt;$sin\ \varphi$&lt;/span&gt; nested within &lt;span class=&quot;math-container&quot;&gt;$P_{\mathscr{l}m}(sin\ \varphi)$&lt;/span&gt;?&lt;/p&gt;&#xA;" OwnerUserId="26265" LastActivityDate="2022-02-01T08:23:14.930" Title="Expression for the gradient of gravity potential in spherical coordinates" Tags="|gravity|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23481" PostTypeId="2" ParentId="19566" CreationDate="2022-01-31T11:44:03.603" Score="6" Body="&lt;p&gt;From my understanding, it should be possible to follow a similar procedure as what is done for calculating the gradient of gravity potential for the Earth (ignoring the potential corrections due to solid tides of the Moon, not sure how significant these would be, but they seem to exist judging from &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014JE004755&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;For that, I believe we can first look at equation 108 of &lt;a href=&quot;http://icgem.gfz-potsdam.de/str-0902-revised.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this technical note&lt;/a&gt;, which defines the potential of an attracting body &lt;span class=&quot;math-container&quot;&gt;$W_a$&lt;/span&gt; in spherical coordinates:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;W_a(r,\lambda,\varphi)=\frac{GM}{R}\sum_{\mathscr{l}=0}^{\mathscr{l}_{max}}\sum_{\mathscr{m}=0}^{\mathscr{l}}\left(\frac{R}{r}\right)^\mathscr{l}P_{\mathscr{lm}}(sin(\varphi))\left((C_{\mathscr{l}m}^Wcos(m\lambda)+S_{\mathscr{l}m}^Wsin(m\lambda)\right)&#xA;$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$GM$&lt;/span&gt; is the gravitational parameter of the central body&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; is the reference radius of the central body&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; is the radial distance of the point at which the potential is to be evaluated, in spherical coordinates&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt; is its longitude&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$\varphi$&lt;/span&gt; is its latitude&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$P_{\mathscr{lm}}$&lt;/span&gt; are the associated Legendre functions of degree &lt;span class=&quot;math-container&quot;&gt;$\mathscr{l}$&lt;/span&gt; and order &lt;span class=&quot;math-container&quot;&gt;$\mathscr{m}$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$C_{\mathscr{l}m}^W$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$S_{\mathscr{l}m}^W$&lt;/span&gt; are the Stokes' coefficients usually distributed with gravity models, and that I most frequently see denoted as Cnm and Snm, or simply as C and S. These are given in the .tab files you linked in comments for the Moon gravity model.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;And equation 120 from the same document gives an expression for the gradient of the gravity potential:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\nabla{W}=W_r\overrightarrow{e_r}+\frac{1}{r\ cos\ \varphi}W_\lambda\overrightarrow{e_\lambda}+\frac{1}{r}W_\varphi\overrightarrow{e_\varphi}&#xA;$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$\overrightarrow{e_r}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\overrightarrow{e_\lambda}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\overrightarrow{e_\varphi}$&lt;/span&gt; are unit vectors of the spherical coordinate system, for which I find &lt;a href=&quot;https://iopscience.iop.org/book/978-1-64327-470-6/chapter/bk978-1-64327-470-6ch1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Figure 1.1 here&lt;/a&gt; quite useful to understand. Just note that said figure uses polar angle instead of latitude and the symbols for each angle are also different.&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$W_r$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$W_\lambda$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$W_\varphi$&lt;/span&gt; are the partial derivatives of &lt;span class=&quot;math-container&quot;&gt;$W$&lt;/span&gt; with respect to &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\varphi$&lt;/span&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;So we basically need these partial derivatives to calculate the gradient of potential in spherical coordinates, after which we can transform to any other system of coordinates/frame of reference. Equation 122 of the ICGEM document gives indeed expressions for each of these 3 partial derivatives:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\dfrac{\partial W}{\partial r} = -\frac{GM}{r^2}\sum_{\mathscr{l}=0}^{\mathscr{l}_{max}}\left(\frac{R}{r}\right)^\mathscr{l}(\mathscr{l}+1)\sum_{m=0}^{\mathscr{l}}P_{\mathscr{l}m}(sin\ \varphi)\left(C_{\mathscr{l}m}^Wcos(m\lambda)+S_{\mathscr{l}m}^Wsin(m\lambda)\right)&#xA;$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\dfrac{\partial W}{\partial \lambda} = \frac{GM}{r}\sum_{\mathscr{l}=0}^{\mathscr{l}_{max}}\left(\frac{R}{r}\right)^\mathscr{l}\sum_{m=0}^{\mathscr{l}}mP_{\mathscr{l}m}(sin\ \varphi)\left(S_{\mathscr{l}m}^Wcos(m\lambda)-C_{\mathscr{l}m}^Wsin(m\lambda)\right)&#xA;$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\dfrac{\partial W}{\partial \varphi} = \frac{GM}{r}\sum_{\mathscr{l}=0}^{\mathscr{l}_{max}}\left(\frac{R}{r}\right)^\mathscr{l}\sum_{m=0}^{\mathscr{l}}\dfrac{\partial P_{\mathscr{l}m}(sin\ \varphi)}{\partial \varphi}\left(C_{\mathscr{l}m}^Wcos(m\lambda)+S_{\mathscr{l}m}^Wsin(m\lambda)\right)&#xA;$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;One thing I have noticed is that the partial derivative with respect to the latitude should be, I believe, multiplied by the cosine of the latitude, if we follow the chain rule for derivatives. &lt;a href=&quot;https://earthscience.stackexchange.com/questions/23480/expression-for-the-gradient-of-gravity-potential-in-spherical-coordinates&quot;&gt;I have asked about this here&lt;/a&gt;, but I am starting to believe the omission of the cosine there might be due to the fact that several recursion algorithms for the calculation of the derivative of Legendre functions are, in reality, calculating directly the product of the derivative by the cosine of latitude. I have verified that this is certainly the case for Lear's algorithm from the NASA document for example. So these values would be ready to use in the expression of that partial derivative of the gravity potential.&lt;/p&gt;&#xA;&lt;p&gt;So the last problem to solve before plugging everything in to be able to calculate the gradient of gravity potential (asides from converting to a Cartesian system of coordinates) is calculating the values of the associated Legendre functions and their derivatives.&lt;/p&gt;&#xA;&lt;p&gt;Regarding the normalization of Legendre functions and Stokes' coefficients, this is indeed key. The raw legendre functions and Cnm/Snm coefficients are related to their normalized versions by a normalization factor &lt;span class=&quot;math-container&quot;&gt;$N_{nm}$&lt;/span&gt;, whose expression is given &lt;a href=&quot;http://mitgcm.org/%7Emlosch/geoidcookbook/node11.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; for example. There seem to be in fact, as you noted, several normalization schemes, with another one being, for example, the so-called Schmidt normalization. In the field of geodesy, however, it seems that (almost) always we use the 4pi, Kaula, geodesy or full normalization (I have seen these 4 terms being applied to the same normalization). The term 4pi normalization seems to be derived from the fact that it makes the squared spherical harmonics yield a value of 4pi when integrated over a sphere.&lt;/p&gt;&#xA;&lt;p&gt;However, according to Vallado's Fundamentals of Astrodynamics and Applications, section 8.6, the practical reason that such normalizations were adopted in this field is that for spherical harmonics of high degree and order, the values of Stokes' coefficients become very small, while the values of the associated Legendre functions become very large. So the coefficients are divided by the mentioned normalization factor, and the Legendre functions are multiplied by it, and their normalized counterparts are denoted by a straight bar over it (I have also seen a curly bar in some sources, but this seems to denote Schmidt partial normalization). E.g., &lt;span class=&quot;math-container&quot;&gt;$\overline{C_{nm}}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The consequence of this is that the product of Stokes' coefficients and Legendre functions remains unaltered regardless of the applied normalization scheme, but it is key that the same normalization is applied to both. The coefficients in the lunar gravity field seem to be fully normalized, so we need matching fully normalized Legendre functions. These can be obtained with relatively simple recursive relationships, for which several exist. But to provide a reference that I found quite good, &lt;a href=&quot;https://ntrs.nasa.gov/api/citations/20110023121/downloads/20110023121.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this NASA document&lt;/a&gt; provides several. I am currently using Lear's algorithm from the 3 in the linked document by the way (unluckily I don't have the code in Python, but happy to provide my implementations in R and C++ if that helps; I decided to write my own implementations because it is quite simple and that way, I am completely certain that the correct normalization is being used). Also, the NASA document provides expressions with which you can verify an implementation of Lear's algorithm.&lt;/p&gt;&#xA;&lt;p&gt;I have tested this for the case of Earth with the GGM05C model by calculating the modulo of the gradient vector and comparing it with the values reported &lt;a href=&quot;http://icgem.gfz-potsdam.de/calcgrid&quot; rel=&quot;nofollow noreferrer&quot;&gt;by this tool&lt;/a&gt; for the same point.&lt;/p&gt;&#xA;&lt;p&gt;Regarding units, Stokes' coefficients (both Cnm and Snm) and the Legendre functions are dimensionless, so the units will be determined by the units of &lt;span class=&quot;math-container&quot;&gt;$GM$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt;. After plugging in the 3 partial derivatives into the expression for the gradient, the dimensions of the result is in [DISTANCE]/[TIME]^2, i.e., acceleration units, which makes sense for it being the gradient of gravity.&lt;/p&gt;&#xA;&lt;p&gt;After converting the gradient to a system of Cartesian coordinates, it can be directly used as the acceleration at that point caused by the gravity field of the central point.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit&lt;/strong&gt;:&lt;/p&gt;&#xA;&lt;p&gt;I have had a go at writing some of the required functions in Python. &lt;a href=&quot;https://github.com/Rafael-Ayala/astroUtils&quot; rel=&quot;nofollow noreferrer&quot;&gt;They can be found here&lt;/a&gt;. I am leaving here an overview of what the workflow would be to reconstruct the gradient of gravity in Python:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Read Cnm and Snm coefficients from model file. It is important to make sure these are &amp;quot;fully normalized&amp;quot; coefficients (although, as far as I have seen, all gravity models of the main celestial bodies use them. But it is important to check in header files).&lt;/li&gt;&#xA;&lt;li&gt;Calculate the values of the normalized associated Legendre functions and their derivatives at the target latitude. This can be done with &lt;a href=&quot;https://github.com/Rafael-Ayala/astroUtils/blob/main/legendre.py&quot; rel=&quot;nofollow noreferrer&quot;&gt;function legendre&lt;/a&gt;, which uses Lear's recursion algorithm and receives as input the desired degree (n) and order (m), as well as the target latitude in radians (not colatitude/polar angle!)&lt;/li&gt;&#xA;&lt;li&gt;Use the Cnm and Snm coefficients together with the Legendre functions and their derivatives to calculate the gradient of gravity at the desired location in spherical coordinates. This can be done with &lt;a href=&quot;https://github.com/Rafael-Ayala/astroUtils/blob/main/gravityGradient.py&quot; rel=&quot;nofollow noreferrer&quot;&gt;function gravityGradientSphericalCoords&lt;/a&gt;, which receives as input, in this order: array of Legendre functions values (Pnm), array of derivatives of Legendre functions values (dPnm), Cnm, Snm, latitude, longitude, r (radial distance of polar coordinates of the target location), the reference radius for the central body whose gravity field is being calculated (R), the gravitational parameter for said central body (GM), the maximum degree to be considered for the calculation of the gradient of potential (n) and the maximum order (m). In reality, the current implementations will use all orders up to degree n.&#xA;This will return the partial derivatives of gravity potential with respect to &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\varphi$&lt;/span&gt; (latitude) and &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt; (longitude), in this order.&lt;/li&gt;&#xA;&lt;li&gt;These can then be input into equation 120 of the mentioned technical note to obtain the gravity gradient in spherical coordinates, and then further transformed into a Cartesian system of coordinates.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit 2&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I think I finally manage to reconstruct and apply Moon's gravity model correctly.&lt;/p&gt;&#xA;&lt;p&gt;There was, however, one more thing to solve that I did not think of before, which is the reference frame for the resulting acceleration by applying the procedure described above.&lt;/p&gt;&#xA;&lt;p&gt;After digging into the documentation of the GRGM1200 series of models, it seems that all the GRGM models use the Moon Principal Axes (MPA) frame of reference. This seems in fact very convenient, since &lt;a href=&quot;https://iopscience.iop.org/article/10.3847/1538-3881/abd414&amp;amp;lang=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;according to section 2.4 here&lt;/a&gt;, the transformation between MPA and Moon-centered ICRF (let's call it SCRF, since it is a selenocentric frame of reference) only requires the Moon libration angles, which, as described &lt;a href=&quot;https://astronomy.stackexchange.com/questions/48264/for-how-many-solar-system-bodies-do-recent-jpl-development-ephemerides-include-l&quot;&gt;in this answer&lt;/a&gt;, are provided in the JPL DE ephemerides.&lt;/p&gt;&#xA;&lt;p&gt;So basically, if we want to obtain an acceleration in SCRF due to the gravity field of the Moon, the process would be:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Get the coordinates of the target point in SCRF frame. If we have them in GCRF (Geocentric ICRF), we can easily obtain them by calculating Moon position with the JPL DE ephemerides and subtracting.&lt;/li&gt;&#xA;&lt;li&gt;Calculate the rotation matrix from MPA to SCRF, and apply the inverse rotation to the position of the target point in SCRF. This yields the position in MPA frame&lt;/li&gt;&#xA;&lt;li&gt;Convert the MPA position to spherical coordinates. This gives a set of spherical coordinates that can be directly input in the procedure I described with my previous edit to calculate the gradient of gravity potential. As mentioned before, it will be initially a vector in spherical coordinates.&lt;/li&gt;&#xA;&lt;li&gt;Convert the gradient in MPA spherical coordinates to cartesian coordinates in the same MPA frame. This can be done with the equations 8-27 of section 8.6.1 of Vallado's Fundamentals of Astrodynamics and Applications, but for completeness, I am reproducing them here:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;a_x = \left(\frac{1}{r}\dfrac{\partial W}{\partial r} - \frac{r_z}{r^2\sqrt{r_x^2+r_y^2}}\dfrac{\partial W}{\partial \varphi}\right)r_x - \left(\frac{1}{r_x^2+r_y^2}\dfrac{\partial W}{\partial \lambda}\right)r_y&#xA;$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;a_y = \left(\frac{1}{r}\dfrac{\partial W}{\partial r} - \frac{r_z}{r^2\sqrt{r_x^2+r_y^2}}\dfrac{\partial W}{\partial \varphi}\right)r_y + \left(\frac{1}{r_x^2+r_y^2}\dfrac{\partial W}{\partial \lambda}\right)r_x&#xA;$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;a_z = \frac{1}{r}\dfrac{\partial W}{\partial r}r_z + \frac{\sqrt{r_x^2+r_y^2}}{r^2}\dfrac{\partial W}{\partial \varphi}&#xA;$$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Where &lt;span class=&quot;math-container&quot;&gt;$a_x$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$a_y$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$a_z$&lt;/span&gt; are the X, Y and Z components of the acceleration in MPA frame, and &lt;span class=&quot;math-container&quot;&gt;$r_x$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$r_y$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$r_z$&lt;/span&gt; are the X, Y and Z components of the target location in MPA frame as well.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;From here, applying the previously calculated rotation matrix from MPA to SCRF will yield the acceleration in the inertial SCRF frame&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I have verified this approach by propagating the position of the GRAIL-A satellite and comparing it with the ephemerides provided by JPL Horizons system. The ephemerides can be obtained &lt;a href=&quot;https://ssd.jpl.nasa.gov/horizons/app.html#/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, directly in SCRF frame (ICRF centered in Moon). The results are quite promising! I propagated the orbit for 1 day, outputting results every 30 minutes, since the 4th of April, 2012 at 00:00:00 (UTC). The following plot shows the difference between my calculated positions and Horizons' ephemerides. Note that propagation was performed without taking into consideration any solar radiation pressure, albedo, or infrared radiation pressure. Only gravity acceleration from the Moon, and attraction by the Sun and all planets as point masses, were considered. The black line is for the case of considering only Moon gravity spherical harmonics up to degree 10, and the red line up to degree 150:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/pDhLV.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pDhLV.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here we have a zoom-in the differences for degree 150:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/zLXlY.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zLXlY.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;And it gets better when considering even higher degrees!&lt;/p&gt;&#xA;&lt;p&gt;That was &lt;strong&gt;fun&lt;/strong&gt;!&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit 3&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;For completion, I implemented a short Python function to convert acceleration in spherical coordinates to Cartesian (body fixed). It can be done with &lt;a href=&quot;https://github.com/Rafael-Ayala/astroUtils/blob/main/accelSPHtoCART.py&quot; rel=&quot;nofollow noreferrer&quot;&gt;function accelSPHtoCART here&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26265" LastEditorUserId="26265" LastEditDate="2022-02-18T02:52:18.020" LastActivityDate="2022-02-18T02:52:18.020" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="23482" PostTypeId="2" ParentId="23471" CreationDate="2022-01-31T13:39:14.460" Score="4" Body="&lt;p&gt;Consider a &lt;a href=&quot;https://en.wikipedia.org/wiki/Galton_board&quot; rel=&quot;nofollow noreferrer&quot;&gt;Galton board&lt;/a&gt;. A simple bead pummels down the cascade of pegs. Can we predict what path it is going to take?&lt;/p&gt;&#xA;&lt;p&gt;Well, in principle, &lt;em&gt;yes&lt;/em&gt; – it's after all just mechanics. If it hits the first peg a little bit to the left of its center, it'll go to the left there. Measure the start state very accurately, and you can predict all that comes later.&lt;/p&gt;&#xA;&lt;p&gt;But it's evidently hopeless to &lt;em&gt;actually&lt;/em&gt; predict the whole path – it's way too sensitive. Even the tiniest change at the start will mean it scatters off the first peg with a slightly different spin, and then this again changes the behaviour at the second, so already after two iterations prediction is sure to be off. For all intents and purposes, the behaviour is just &lt;em&gt;random&lt;/em&gt; then, despite following deterministic microscopic dynamics.&lt;/p&gt;&#xA;&lt;p&gt;Roughly the same reason is responsible for weather forecasts being little use over more than a week.&lt;/p&gt;&#xA;&lt;p&gt;Nevertheless, what we &lt;em&gt;can&lt;/em&gt; say with very good confidence is that the bead is going to end up somewhere near the middle after 1000 rows of pegs. It's not strictly speaking &lt;em&gt;impossible&lt;/em&gt; that it goes to the left twice as often as to the right, but so very unlikely that we might rather worry about the board being destroyed by a plane crashing into the lab.&lt;/p&gt;&#xA;&lt;p&gt;And if all the pegs are slightly biased to make it 5% more likely for the bead to go to the right at each of them somehow, that's not going to be evident from observing a couple of beads on the first rows – it'll still look totally unpredictable. However, it &lt;em&gt;will&lt;/em&gt; show up clearly in the shifted peak of the distribution after 1000 rows.&lt;/p&gt;&#xA;" OwnerUserId="12095" LastEditorUserId="14991" LastEditDate="2022-01-31T16:44:39.710" LastActivityDate="2022-01-31T16:44:39.710" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23483" PostTypeId="1" CreationDate="2022-01-31T14:55:54.190" Score="1" ViewCount="94" Body="&lt;p&gt;I have the CORDEX netcdf data and I would like to convert them to raw text file that can be used for importing data to DHI Mike.&lt;/p&gt;&#xA;&lt;p&gt;To give more context, I have previously converted the ECMWF netcdf (historical) data into the the raw text compatible for DHI Mike, using a Python script. In &lt;a href=&quot;https://github.com/mahdisamieenia/sample-files&quot; rel=&quot;nofollow noreferrer&quot;&gt;this Github repository&lt;/a&gt;, I have these files:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&amp;quot;2020.nc&amp;quot; is the ECMWF netcdf data&lt;/li&gt;&#xA;&lt;li&gt;&amp;quot;2020 (2).txt&amp;quot; the converted text file&lt;/li&gt;&#xA;&lt;li&gt;&amp;quot;py_ecmwf_gridseries_convertor.ipynb&amp;quot; the python script for the required conversion.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Now what I am trying to achieve is to do a similar conversion, but this time on the CORDEX (projected) data. In the same repository I have a sample CORDEX file named &amp;quot;out1.nc&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;I would appreciate it if the community can point me toward the right direction.&lt;/p&gt;&#xA;&lt;p&gt;P.S.&lt;/p&gt;&#xA;&lt;p&gt;If it helps, the metadata in the raw text file is as follows:&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Title&amp;quot; &amp;quot;caspian-sea&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Dim&amp;quot; 2&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Geo&amp;quot; &amp;quot;LONG/LAT&amp;quot; 47 31 0&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Time&amp;quot; &amp;quot;EqudistantTimeAxis&amp;quot; &amp;quot;1970-01-11&amp;quot; &amp;quot;04:06:00&amp;quot; 4 3600&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;NoGridPoints&amp;quot; 45 33&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Spacing&amp;quot; 0.25 0.25&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;NoStaticItems&amp;quot; 0&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;NoDynamicItems&amp;quot; 1&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Item&amp;quot; &amp;quot;2 metre temperature&amp;quot; &amp;quot;t2m&amp;quot; &amp;quot;K&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;NoCustomBlocks 1&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;M21_Misc&amp;quot; 1 7 0 -1E-030 -900 -999 -1E-030 -1E-030 -1E-030&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Delete&amp;quot; -1E-030&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;DataType&amp;quot; 0&lt;/p&gt;&#xA;" OwnerUserId="26348" LastEditorUserId="26348" LastEditDate="2022-03-13T16:42:22.913" LastActivityDate="2022-03-13T16:42:22.913" Title="How to convert CORDEX netcdf data to be used for importing data to DHI Mike?" Tags="|climate|netcdf|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23484" PostTypeId="2" ParentId="23471" CreationDate="2022-01-31T20:32:38.653" Score="0" Body="&lt;p&gt;My understanding is that errors in both types of models result from subtle differences in the approaches.&lt;/p&gt;&#xA;&lt;p&gt;In weather models, the full Navier-Stokes equations are solved. Due to the non-linear and hence chaotic nature of these equations, one generates an uncertainty in the time-evolution by varying the initial conditions, such as the temperature &lt;span class=&quot;math-container&quot;&gt;$T_0$&lt;/span&gt; by some Gaussian, or other prior function.&lt;/p&gt;&#xA;&lt;p&gt;Climate models on the other hand, have the chaoticity averaged out from them, hence varying the initial conditions will produce no variability in the long-term evolution. That variability there originates in the uncertainties of the evolution parameters, like the cloud condensation pressure.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2022-01-31T20:32:38.653" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23485" PostTypeId="2" ParentId="23471" CreationDate="2022-01-31T20:39:51.193" Score="1" Body="&lt;p&gt;The claim in the quote is not what the question title is asking about. Climate models &lt;em&gt;do&lt;/em&gt; accumulate error over time, just as weather models (and most models attempting to predict the future of almost anything) do.&lt;/p&gt;&#xA;&lt;p&gt;What the quote is saying is that climate models are not based on weather models. Weather models are designed to produce very high precision forecasts (relative to climate models, at least.) This requires them to use very precise (and very recent) inputs to the models, such as current surface temperatures, pressure gradients, wind fields, jet stream/streak locations, frontal boundaries, temperatures and winds aloft, etc. in order to predict the likely weather at a particular location at a particular time of day a couple of days from now.&lt;/p&gt;&#xA;&lt;p&gt;Climate models aren't just plugging today's weather observations into the GFS, NAM, and EURO models and grabbing the predicted conditions for 3:00 pm on Jan 31, 2072. Instead, their inputs are averages over long periods of time (generally decades or more) with a goal of predicting averages over long periods of time (again, generally decades or more.) This doesn't mean that error doesn't accumulate over time; it does. But the error doesn't accumulate over time on anywhere near the same scale as in weather forecasts because the inputs (and outputs) are &lt;em&gt;far&lt;/em&gt; less variable than with weather forecasts, due to averaging over much, much longer periods of time.&lt;/p&gt;&#xA;&lt;p&gt;As with almost any sort of time data - especially rather variable data like weather observations - averages over long periods of time are generally &lt;em&gt;much&lt;/em&gt; more stable than instantaneous observations. Error still accumulates over time, just not nearly as quickly.&lt;/p&gt;&#xA;" OwnerUserId="1099" LastActivityDate="2022-01-31T20:39:51.193" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23486" PostTypeId="2" ParentId="23480" CreationDate="2022-02-01T08:23:14.930" Score="3" Body="&lt;p&gt;The chain rule is already included, since the derivative is taken with respect to &lt;span class=&quot;math-container&quot;&gt;$\varphi$&lt;/span&gt;. Note that&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\frac{\partial P_{\ell m}(\sin(\varphi))}{\partial \varphi} = \frac{\partial P_{\ell m}(\sin(\varphi))}{\partial \sin(\varphi)}  \frac{\partial \sin(\varphi)}{\partial \varphi}.&#xA;\end{equation}&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="18833" LastActivityDate="2022-02-01T08:23:14.930" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23488" PostTypeId="1" CreationDate="2022-02-02T21:28:11.107" Score="1" ViewCount="22" Body="&lt;p&gt;Anybody know of software or a website out there that will try to predict the oceanic water mass based on temperature and salinity data? As you might due visually with a T-S diagram?&lt;/p&gt;&#xA;" OwnerUserId="2502" LastActivityDate="2022-02-02T21:28:11.107" Title="Oceanic water mass predictor?" Tags="|oceanography|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23489" PostTypeId="1" CreationDate="2022-02-03T02:09:04.140" Score="6" ViewCount="274" Body="&lt;p&gt;The shape of a volcano generally depends strongly on the viscosity of the molten rock used to make it:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;If the magma/lava (&amp;quot;magva&amp;quot;?) is relatively fluid, it flows out gently, and you get a pancake-shaped &lt;a href=&quot;https://en.wikipedia.org/wiki/Shield_volcano&quot; rel=&quot;nofollow noreferrer&quot;&gt;shield volcano&lt;/a&gt;, with very gentle slopes made up almost entirely of solidified bulk lava flows; gasses dissolved in lower-viscosity magvas are easily burped out, making explosions rare unless liquid water comes into contact with hot magva (either underground or on the surface), and, as such, pyroclastic deposits make up only a very small proportion of the bulk of these volcanoes, while the low viscosity of the erupted lava allows it to flow long distances before solidifying (hence the gentle slopes).&lt;sup&gt;1&lt;/sup&gt;  Note (this will become important later) that these magvas are fluid and low-viscosity &lt;em&gt;by magva standards&lt;/em&gt;; by human standards, most such magvas are still highly-viscous, flowing like shampoo or maple syrup rather than like water.&lt;/li&gt;&#xA;&lt;li&gt;More-viscous magvas are harder for gasses to gently bubble out of, and more likely to explode when brought up from the bowels of the earth, producing explosions and pyroclastic deposits; even when it erupts without exploding, the thick, pasty lava flows much more slowly and doesn't get as far before it hardens (instead of maple syrup, think peanut butter).  The result is a moderately-steep-sided &lt;a href=&quot;https://en.wikipedia.org/wiki/Stratovolcano&quot; rel=&quot;nofollow noreferrer&quot;&gt;stratovolcano&lt;/a&gt;, composed of multiple layers of solidified lava flows, welded pyroclastic deposits (&lt;a href=&quot;https://en.wikipedia.org/wiki/Ignimbrite&quot; rel=&quot;nofollow noreferrer&quot;&gt;ignimbrites&lt;/a&gt;), pressed-together-but-unwelded ash deposits (&lt;a href=&quot;https://en.wikipedia.org/wiki/Tuff&quot; rel=&quot;nofollow noreferrer&quot;&gt;tuff&lt;/a&gt;), and mixtures of any combination of the three.&lt;/li&gt;&#xA;&lt;li&gt;If the magva involved is sufficiently viscous (going from peanut butter to caramel), it simply &lt;em&gt;can't&lt;/em&gt; erupt to the surface without exploding as the dissolved gasses depressurize into trapped bubbles, and you don't get any extrusive lava flows at all (at least early on in the eruption sequence).&lt;sup&gt;3, 4&lt;/sup&gt;  Instead, if the eruption is on a small scale, you get a steep-sided pile of ash and broken rocks blown from the eruption vent (known as a &lt;a href=&quot;https://en.wikipedia.org/wiki/Cinder_cone&quot; rel=&quot;nofollow noreferrer&quot;&gt;cinder cone&lt;/a&gt;);&lt;sup&gt;5&lt;/sup&gt; if larger amounts of magva are involved, the eruption starts getting explodey enough that it &lt;em&gt;blows away&lt;/em&gt; more material than it deposits locally, and (especially when combined with the tendency of large, newly-emptied magma chambers to collapse under the weight of all the rock on top of them) you get &lt;a href=&quot;https://en.wikipedia.org/wiki/Caldera&quot; rel=&quot;nofollow noreferrer&quot;&gt;a big hole in the ground&lt;/a&gt;,&lt;sup&gt;6&lt;/sup&gt; rather than the classical hill-or-mountain-shaped volcano.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Remember, even shield-volcano lavas, like you see in places like Hawaiʻi, are generally still quite viscous, sticky, and slow-flowing by human standards.&lt;/p&gt;&#xA;&lt;p&gt;Now consider two volcanoes in the East African Rift whose lavas are extremely fluid and fast-moving &lt;em&gt;even by human standards&lt;/em&gt; - &lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Nyiragongo&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nyiragongo&lt;/a&gt; in the far-northeastern Democratic Republic of the Congo, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Ol_Doinyo_Lengai&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ol Doinyo Lengai&lt;/a&gt; in northern Tanzania.  Given the types of volcanoes you get from lavas that flow like maple syrup, one would expect that &lt;em&gt;these&lt;/em&gt; volcanoes, with lavas that flow quite literally like water, would be shield volcanoes, and very flat ones indeed.&lt;sup&gt;7&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;Instead, both Nyiragongo and Ol Doinyo Lengai are fairly-steep-sided stratovolcanoes.&lt;sup&gt;8&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;How did these two volcanoes, both of them having lavas more fluid than those of most shield volcanoes, end up as steep-sided stratovolcanoes?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt;: This should in no way be taken as meaning that shield volcanoes are incapable of reaching great heights.  Quite the contrary - not just the tallest volcanoes, but the tallest mountains &lt;em&gt;of any sort&lt;/em&gt;, both &lt;a href=&quot;https://en.wikipedia.org/wiki/Mauna_Kea&quot; rel=&quot;nofollow noreferrer&quot;&gt;on Earth&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Olympus_Mons&quot; rel=&quot;nofollow noreferrer&quot;&gt;in the entire solar system&lt;/a&gt;,&lt;sup&gt;2&lt;/sup&gt; are shield volcanoes.  (This makes sense when you think about it, as their more-fluid magvas have an easier time percolating up through the plumbing to the surface without getting stuck along the way, and these docile volcanoes are the least prone to blowing themselves to bits.)  However, this tallness, in a shield volcano, requires a truly-enormous horizontal extent to support it.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;2&lt;/sup&gt;: Granted, the latter of those has the advantage of being on Mars, where the lower gravity means that liquids of all sorts, including lava, see less urgency in flowing downhill, allowing volcanoes to be steeper and pile up higher than they would on Earth.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;3&lt;/sup&gt;: Over the course of an explosive caramel-volcano eruption, some of the magva deeper in the volcano's belly &lt;em&gt;can&lt;/em&gt; sometimes depressurize slowly enough for the bubbles to - very slowly - work themselves out in pace with their generation, allowing this portion of the magva to degas nonviolently; late in the eruption sequence, this degassed magva can reach the surface in effusive lava flows.  This forms only a small portion of the volcano's total bulk, though.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;4&lt;/sup&gt;: Of course, if the magva cools and solidifies while still deep underground and under high pressure, the gasses don't get a chance to explode it, and you end up with large solid formations of bulk intrusive rock (such as the granites that form the cores of many a continent), even from the most viscous magvas.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;5&lt;/sup&gt;: As @Jean-MariePrival correctly points out in &lt;a href=&quot;https://earthscience.stackexchange.com/questions/23489/how-does-one-get-a-steep-sided-stratovolcano-with-extremely-fluid-low-viscosity#comment55170_23489&quot;&gt;their comment&lt;/a&gt;, cinder cones can form from magvas with a very wide range of viscosities, and most cinder cones actually have low-to-midrange-viscosity magva (but are still steep, since it's still a pile of rocks and ash, which don't tend to flow very well); however, cinder cones can still form even with extremely-viscous magva that's too pasty and explodey to make a shield or even a stratovolcano, hence their being mentioned in the third bullet point rather than one of the first two.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;6&lt;/sup&gt;: The relative contributions of the blast-out effect and the chamber-collapse effect vary between volcanoes and between eruptions; in general, holes in the ground produced by smaller and/or less-explosive eruptions are primarily due to collapse, while those produced by really really big explosions, as one might expect, owe more to the &lt;em&gt;boom&lt;/em&gt; side of things.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;7&lt;/sup&gt;: Indeed, Nyiragongo's sister volcano, &lt;a href=&quot;https://en.wikipedia.org/wiki/Nyamuragira&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nyamuragira&lt;/a&gt;, is a bog-standard shield.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;8&lt;/sup&gt;: In Nyiragongo's case, the combination of steep sides and extremely-fluid lava leads to the fastest lava flows of any volcano in the world.  Lava flows that move faster than many speed limits are, for obvious regions, extremely dangerous; this is why Nyiragongo is one of the sixteen &lt;a href=&quot;https://en.wikipedia.org/wiki/Decade_Volcanoes&quot; rel=&quot;nofollow noreferrer&quot;&gt;Decade Volcanoes&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="12549" LastEditorUserId="12549" LastEditDate="2022-02-08T21:23:59.033" LastActivityDate="2022-07-28T09:22:40.697" Title="How does one get a steep-sided stratovolcano with extremely fluid, low-viscosity lava?" Tags="|volcanology|geomorphology|magmatism|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23490" PostTypeId="2" ParentId="23471" CreationDate="2022-02-03T05:12:33.777" Score="0" Body="&lt;p&gt;Climate models are not purely mathematical constructs that exist independent of physical reality; various parameters represent real world conditions and the modeling seeks to incorporate known climate processes as closely as possible.&lt;/p&gt;&#xA;&lt;p&gt;Representation of those processes and interaction within a model seeks to conform with what is known about the physical processes; if it is well modeled it won't be able to do something that isn't physically possible - like have decades of enhanced greenhouse effect with reduced outbound IR but no ocean warming. Or &lt;em&gt;statistically unlikely&lt;/em&gt;, like an iterative succession of uncertainty errors biased in one direction of the kind I suspect Mr Peterson imagines, where the statistically unlikely but physically possible tails of probability bell curves are considered to be just as likely as near the middle of the bell curve.&lt;/p&gt;&#xA;&lt;p&gt;We really should assume a genuine intent by climate scientists to better understand climate process interactions and an intent to produce the more accurate climate projections that they are being asked to provide. Accusations otherwise - of manipulating climate data or modeling to support a political agenda or to cover incompetence or scam grant money - should come with evidence and be presented to the proper authorities.&lt;/p&gt;&#xA;&lt;p&gt;Hindcasting - taking known past real-world conditions and modeling the climate within time frames where the real world conditions are known - is an excellent check on how well they work.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2022-02-03T05:12:33.777" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23491" PostTypeId="1" CreationDate="2022-02-03T16:34:55.017" Score="1" ViewCount="74" Body="&lt;p&gt;I want to run an experiment: collect leafs in forests to try to stabilize them and prevent from rotting and emitting greenhouse gases.&lt;/p&gt;&#xA;&lt;p&gt;I live in an area with temperate deciduous forest and have a fair idea of annual leaf litter production.&lt;/p&gt;&#xA;&lt;p&gt;But how does that compare to tropical deciduous forest (and any other forest for that matter)?&lt;/p&gt;&#xA;" OwnerUserId="26372" LastActivityDate="2022-02-05T07:51:17.317" Title="Is there more leaf litter in tropical decisuous forests or temperate deciduous forests" Tags="|climate-change|forest|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23493" PostTypeId="1" CreationDate="2022-02-04T09:16:57.787" Score="9" ViewCount="211" Body="&lt;p&gt;For validation of model data, I want to compare the ozone data from model to the satellite results downloaded from the &lt;a href=&quot;https://avdc.gsfc.nasa.gov/pub/data/satellite/Aura/OMI/V03/L2/OMPROFOZ&quot; rel=&quot;nofollow noreferrer&quot;&gt;following link&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;The satellite data are in DU(Dobson Unit) while the model data are in ppbv. To make them comparable, I converted the units of satellite data from DU to ppbv from the formula specified in the README file.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Pxkak.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Pxkak.png&quot; alt=&quot;formula for conversion&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But I have problem converting values of average kernel(AKs). The readme file specifies that&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Note the AKs for different units (e.g., DU or ppbv) are different, the DU/DU does not cancel out because the conversion from DU to ppbv varies with altitude (e.g. resulting from different T, P).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;But, I am not sure what is the right way convert the values of Average Kernel from DU/DU to ppbv/ppbv so that I can use its values.&lt;/p&gt;&#xA;" OwnerUserId="20906" LastEditorUserId="20906" LastEditDate="2022-02-15T03:33:22.350" LastActivityDate="2022-02-15T03:33:22.350" Title="How to convert units of averaging kernel from DU/DU to ppbv/ppbv" Tags="|atmosphere-modelling|satellites|validation|" AnswerCount="0" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="23494" PostTypeId="1" CreationDate="2022-02-04T13:07:10.890" Score="1" ViewCount="33" Body="&lt;p&gt;When we compare sentinel-1 SAR orthorectified 8-bit image vs a very high resolution panchromatic 8-bit image, the panchromatic cells are a resemblance of signal amplitude in an 8-bit scale (0-255). And, if I've got it right, each of the SAR cells is a resemblance of how much amplitude the antenna is recorded (of the wave height and not length).&lt;/p&gt;&#xA;&lt;p&gt;Given the below image, &lt;strong&gt;which are on the same extents&lt;/strong&gt;, each of the SAR pixels (cells) covers the same area as for 17689 panchromatic cells (so 6 SAR cells cover ~ 106400 pan. cells ).&lt;/p&gt;&#xA;&lt;p&gt;But the question is: a 20x20m pixel covers a lot of different materials (cars, land, water, cement and etc.), so what constitutes which number (how much amplitude) goes to each of the 20x20m cells.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Is it an average of all the incoming amplitudes to the SAR antenna?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Is it the strongest amplitude that wins the pixel value?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Or a different story?&lt;/strong&gt; It would be much obliged if you attach some additional reference to your answer.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;I've already asked this question on &lt;a href=&quot;https://gis.stackexchange.com/questions/422875/the-nature-of-sar-pixel-value-vs-of-panchromatic-pixel-value&quot;&gt;another forum&lt;/a&gt; but no one has answered it.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eEkUd.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eEkUd.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26377" LastActivityDate="2022-02-04T13:07:10.890" Title="The-nature-of-sar-pixel-value-vs-of-panchromatic-pixel-value" Tags="|remote-sensing|electromagnetism|radar|" AnswerCount="0" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23495" PostTypeId="2" ParentId="23489" CreationDate="2022-02-05T07:47:38.250" Score="1" Body="&lt;p&gt;Ol Doinyo Lengai is a carbonatite volcano (the only active one known today) that produces relatively cool lava that quickly solidifies.  The large lava lake in Mount Nyiragongo would, I suspect, cool the lava sufficiently that eruptions there would also quickly solidify.&lt;/p&gt;&#xA;" OwnerUserId="8513" LastActivityDate="2022-02-05T07:47:38.250" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23496" PostTypeId="2" ParentId="23491" CreationDate="2022-02-05T07:51:17.317" Score="1" Body="&lt;p&gt;Biomass tend to be superior, however it's gone fast. Tropical moist forests have &lt;a href=&quot;https://mongabay-images.s3.amazonaws.com/1200/indonesia/indonesia_sulawesi_170358.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;little&lt;/a&gt; leaf litter, because of the climate and humidity; dead organic litter &lt;a href=&quot;https://www.sidmartinbio.org/how-the-tropical-forest-decomposition-rate-is-more-than-temperate-forest/&quot; rel=&quot;nofollow noreferrer&quot;&gt;decomposes&lt;/a&gt; fairly fast. These organisms thrive in the warm, moist environment and it's seldom dry, so fungi proliferate uninpuned and are able to decompose organic matter very rapidly. Waste that would typically take one year to decompose in a regular temperate forest would decompose within six weeks in the tropics.&lt;/p&gt;&#xA;&lt;p&gt;In the tropics, leaves fallen will dissappear in six weeks.&#xA;Temperate: one year&#xA;cooler range temperate: 2-3 years&#xA;Cold boreal region: Decades&#xA;Mediterranean climate: Periodic Fire deals with aiding decomposition&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2022-02-05T07:51:17.317" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23497" PostTypeId="2" ParentId="21161" CreationDate="2022-02-05T07:55:22.573" Score="0" Body="&lt;p&gt;Because Washington has many river channels.The rivers of Western Washington flood almost every year. Snohomish, Skagit and other rivers flood, Seattle is largely spared, city knowing full well floods would be an issue for a city that supports rainforest ecosystem...........has drainage.&#xA;Seattle is 53 meters (173 feet) above sea level and on mountainous terrain, so waters very seldom flood or inundate. Floods dominate flat terrain or valleys, which Seattle is Neither.........&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2022-02-05T07:55:22.573" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23499" PostTypeId="2" ParentId="23447" CreationDate="2022-02-06T05:44:07.247" Score="1" Body="&lt;p&gt;Geothermal power has vast applications but it suffers several drawbacks....&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Economics: Power has has a 20-30% &lt;a href=&quot;https://web.archive.org/web/20130521174852/http://www.georestore.com/cms_files/Geothermal%20Economics%20101%20-%20Glacier%20Partners.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;failure rate at drill sites&lt;/a&gt; where potential sites become unrecoverable. So economic failure, Wells a mile deep can cost tens of millions of dollars and if it's loose, seismic rock regions the hole can collapse before even being exploited.&lt;/li&gt;&#xA;&lt;li&gt;Availability: while abundant as an energy resource; it is highly diffused thru much of the world, accessing hot spots may require drilling several thousand meters, an expensive endeavor, especially with a 20-30 percent failure rate.&#xA;And where it's ubiquitous may not be near population centers, thus demand very long transmission distances negating their advantage; many plants are small (never more than 10-100 MW) and not worth investment.&lt;/li&gt;&#xA;&lt;li&gt;Depletion risk: Hot spots should be used cautiously before risking depletion. Dumping excess water for steam runs risk of depleting thermal source.&lt;/li&gt;&#xA;&lt;li&gt;Energy Density/Thermodynamic efficiency: Average suitable temps of most wells; exceed seldomly 150 degrees Celsius......A fairly low temperature for a working fluid, compared to fossil fuels which can run as hot as 500-1000 degrees Celsius or nuclear which runs at 280-300(some experimental at 495-600), geothermal has a thermal efficiency of 7-10% (Nuclear 33-35%, Fossil: 33-90%)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;However &lt;a href=&quot;https://www.youtube.com/watch?v=87gUU1vUlqU&quot; rel=&quot;nofollow noreferrer&quot;&gt;Other options&lt;/a&gt; for their exploitation involve using Low boiling point (below 100 degrees C) closed cycle engines. Instead of boiling water, they heat up ammonia or a hydrocarbon based refrigerant.&lt;/p&gt;&#xA;&lt;p&gt;Geothermal can also be utilized for energy efficient space heating and &lt;a href=&quot;https://www.youtube.com/watch?v=qA3YGYELZ98&quot; rel=&quot;nofollow noreferrer&quot;&gt;greenhouse&lt;/a&gt; management thus mitigating significant fossil energy consumption.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2022-02-06T05:44:07.247" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23501" PostTypeId="1" AcceptedAnswerId="23504" CreationDate="2022-02-06T14:21:36.057" Score="2" ViewCount="162" Body="&lt;p&gt;This is the &lt;a href=&quot;https://www.google.com/maps/@42.6606027,7.2738589,68051m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;location&lt;/a&gt;. It is close to the French coast.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nJQEK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nJQEK.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="1315" LastEditorUserId="6298" LastEditDate="2022-02-06T17:33:08.873" LastActivityDate="2022-02-07T16:22:07.507" Title="What are all those &quot;spots&quot; on the Mediterranean Sea floor?" Tags="|sea-floor|ground-truth|satellite-oddities|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23502" PostTypeId="5" CreationDate="2022-02-06T17:32:45.307" Score="0" Body="" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-02-06T17:32:45.307" LastActivityDate="2022-02-06T17:32:45.307" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23503" PostTypeId="4" CreationDate="2022-02-06T17:32:45.307" Score="0" Body="Questions about peculiar features seen on satellite imagery such as Google Earth." OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-02-06T17:32:45.307" LastActivityDate="2022-02-06T17:32:45.307" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23504" PostTypeId="2" ParentId="23501" CreationDate="2022-02-07T16:22:07.507" Score="3" Body="&lt;p&gt;Since this is the &amp;quot;satellite view&amp;quot; and the features don't show up in a bathymetry map, they are most likely surface artifacts from something like the large cruise ships that frequent the French Riviera. (The depth at this location is about 2,700 meters.)&lt;/p&gt;&#xA;&lt;p&gt;Here is the base sonar map of the ocean floor at those coordinates, from NOAA's &lt;a href=&quot;https://www.ncei.noaa.gov/maps/bathymetry/&quot; rel=&quot;nofollow noreferrer&quot;&gt;National Center for Environmental Information's bathymetry data viewer&lt;/a&gt;.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/xpA6u.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xpA6u.png&quot; alt=&quot;NCEI Bathymetry map&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2022-02-07T16:22:07.507" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23505" PostTypeId="1" AcceptedAnswerId="23506" CreationDate="2022-02-08T08:29:36.400" Score="4" ViewCount="188" Body="&lt;p&gt;I am trying to understand the atmospheric ppm data, specifically around how CH&lt;sub&gt;4&lt;/sub&gt; decays to CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&lt;p&gt;This data says 2017 CH&lt;sub&gt;4&lt;/sub&gt; is about 1850ppm, and 2017 CO&lt;sub&gt;2&lt;/sub&gt; is 402ppm increasing about 3ppm/year. (&lt;a href=&quot;https://www.eea.europa.eu/data-and-maps/daviz/atmospheric-concentration-of-carbon-dioxide-5&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.eea.europa.eu/data-and-maps/daviz/atmospheric-concentration-of-carbon-dioxide-5&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;I've also read that CH&lt;sub&gt;4&lt;/sub&gt; has a half-life in the atmosphere of about 9 years, decaying with the chemical equation CH&lt;sub&gt;4&lt;/sub&gt; + O&lt;sub&gt;2&lt;/sub&gt; → CO&lt;sub&gt;2&lt;/sub&gt; + H&lt;sub&gt;4&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;So if you'd expect methane's 1850ppm to decay to 925ppm over 9 years, that means you'd also expect to see an increase of 925ppm of CO&lt;sub&gt;2&lt;/sub&gt;, or about 100ppm/yr just from methane decay. That'd be insanely high. But the data I linked earlier shows an increase of 3ppm.&lt;/p&gt;&#xA;&lt;p&gt;So what am I missing in this analysis?&lt;/p&gt;&#xA;" OwnerUserId="26397" LastEditorDisplayName="user20559" LastEditDate="2022-02-08T11:38:23.423" LastActivityDate="2022-02-09T03:44:23.163" Title="If methane decays to $\small\sf{CO_2}$ in the atmosphere, shouldn't there be much more $\small\sf{CO_2}$?" Tags="|atmosphere|atmospheric-chemistry|carbon|methane|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23506" PostTypeId="2" ParentId="23505" CreationDate="2022-02-08T14:11:22.543" Score="6" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;So what am I missing in this analysis?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The linked data says 2017 CH&lt;sub&gt;4&lt;/sub&gt; was about 1850 &lt;strong&gt;ppb&lt;/strong&gt;, not 1850 &lt;strong&gt;ppm&lt;/strong&gt;. Dividing parts per billion (ppb) by 1000 results in parts per million (ppm).  In other words, the atmospheric methane concentration was about 1.850 ppm in 2017. Assuming an exponential decay with a half life of 9 years means that about 0.14 ppm &lt;span class=&quot;math-container&quot;&gt;$\left(1850*(1-2^{-1/9}\,)\right)$&lt;/span&gt; of the 2.4 ppm increase in the 2017 to 2018 CO&lt;sub&gt;2&lt;/sub&gt; concentration was due to  methane decomposition. That's a small but not insignificant portion of the increase.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-02-08T14:11:22.543" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23507" PostTypeId="1" AcceptedAnswerId="23508" CreationDate="2022-02-08T14:39:25.307" Score="4" ViewCount="172" Body="&lt;p&gt;Is it possible to consider the occurrences of precipitation in two different places to be independent phenomena?&lt;/p&gt;&#xA;" OwnerUserId="26399" LastActivityDate="2022-04-05T05:32:01.093" Title="Precipitation in two places as independent phenomena" Tags="|meteorology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23508" PostTypeId="2" ParentId="23507" CreationDate="2022-02-08T16:02:10.147" Score="6" Body="&lt;p&gt;Depends quite a bit upon the geographic scale between the two places.  But in general there will tend to be some interdependence, even for locations large distances apart, as the large-scale upper atmosphere is controlled by a &lt;a href=&quot;https://www.weather.gov/jetstream/basic&quot; rel=&quot;nofollow noreferrer&quot;&gt;wave pattern&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gtLkT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gtLkT.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This flow pattern &lt;a href=&quot;https://www.weather.gov/jetstream/longshort&quot; rel=&quot;nofollow noreferrer&quot;&gt;continues around the globe&lt;/a&gt;.  In addition, the fact that the temperature of the Pacific Ocean &lt;a href=&quot;https://www.climate.gov/news-features/featured-images/global-impacts-el-ni%C3%B1o-and-la-ni%C3%B1a&quot; rel=&quot;nofollow noreferrer&quot;&gt;has impacts on weather almost worldwide&lt;/a&gt; shows just significant interconnection can be:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NBI1n.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NBI1n.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The most independent phenomena will tend to be mesoscale (local) phenomena like seabreeze thunderstorms and lake effect snow... though even they tend to have some fair reliance upon wind direction and pressure regime, which are involved with the larger pattern.  The amount of dependence between two reasonably distant locations though will often be quite small.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, it's quite common to have a few days where rain thousands of miles apart is not just slightly correlated, but directly the consequence of the same feature, such as this front from January 2013 that Wikipedia &lt;a href=&quot;https://en.wikipedia.org/wiki/Squall_line#/media/File:Eastern_US_squall_line_30_January_2013_radar_mosaic.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;had saved&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dL6k5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dL6k5.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So fundamentally there is some, at least small, interconnection between precipitation events at any two locations globally.  But if you can choose locations with consideration of geographic (distance/surroundings) and meteorological factors (seasons), you can likely get results that are empirically basically independent, as the large-scale pattern connection between them is such a minor contributing factor compared to other influences.  &lt;strong&gt;In other words, there is a dependent relationship part between the precipitation at any two locations and an independent part.  Statistically the dependence is often very (very) small for many location choices, but is greater for nearer locations and in certain seasons/weather events.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;If you are, for example, designing a school science fair experiment, you would likely struggle if you wanted to see &lt;a href=&quot;https://www.cleveland.com/weather/blog/2018/02/meet_20_other_weather-predicti.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;which animal specie is best at predicting the weather&lt;/a&gt; (spoiler: none!) by looking at snowfall totals, because there's quite a lot of dependence between the weather at the sites listed since they are mostly in the same region and their winter/spring climate is heavily tied to the large-scale upper atmospheric pattern and storm system tracks, so that would likely swamp out any &amp;quot;contribution&amp;quot; from the animal (in addition, geographical differences, such as terrain and relationship to bodies of water, would be another huge uncontrolled independent factor).  On the other hand, if you were wanting to compare the influence of industrial pollution on the number of rainfall days, and carefully chose, for example, distant tropical coastal sites (perhaps a site in SE Asia versus one in the Caribbean) with similar weather influences/patterns, and looked at large datasets... you might be able to fairly inspect the magnitude of such influence for the chosen regime type.&lt;/p&gt;&#xA;&lt;p&gt;I often found meteorological phenomena to be challenging to design simple science fair projects around, as there are so many different interconnected variables, and it is hard to control most and leave one independent.  That's why many meteorological studies are often focused more on &lt;a href=&quot;https://en.wikipedia.org/wiki/Multivariate_statistics&quot; rel=&quot;nofollow noreferrer&quot;&gt;multivariate analysis&lt;/a&gt; of large datasets and effects like &lt;a href=&quot;https://en.wikipedia.org/wiki/Urban_heat_island&quot; rel=&quot;nofollow noreferrer&quot;&gt;urban heat island&lt;/a&gt; took quite a bit of careful analysis to recognize.  It's not impossible, but to find two locations that are for all intents and purposes seeing independent weather events, while still not being controlled by other factors like their climate regimes/topography, can be quite challenging.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;But while fundamentally no precipitation events are ever absolutely perfectly independent, with the right distance and location considerations their interdependence can be so negligible so as to consider the precipitation independent phenomena.  I would consult a meteorologist to analyze how independent two such sites may be.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-04-04T22:39:37.857" LastActivityDate="2022-04-04T22:39:37.857" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="23509" PostTypeId="1" CreationDate="2022-02-08T23:58:56.490" Score="1" ViewCount="31" Body="&lt;p&gt;I'm looking for a formula library like &lt;a href=&quot;https://www.fxsolver.com/browse/&quot; rel=&quot;nofollow noreferrer&quot;&gt;fxSolver&lt;/a&gt; but specifically for Earth science formulas. I &lt;em&gt;could&lt;/em&gt; rummage through scientific papers like a nerd racoon, but first I want to make sure there isn't a website that has collected the equations I want. All of my &amp;quot;knowledge&amp;quot; in this field comes from intuition and a small number of basic qualitative descriptions, hence why I want to be able to browse through them and cherry pick the ones I need to learn about.&lt;/p&gt;&#xA;" OwnerUserId="26404" LastActivityDate="2022-02-08T23:58:56.490" Title="Are there any online earth science formula/equation libraries?" Tags="|models|numerical-modelling|database|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23510" PostTypeId="1" CreationDate="2022-02-09T02:32:51.317" Score="2" ViewCount="777" Body="&lt;p&gt;How long would it take for a steel can to decompose in a landfill (no oxygen, no sun)? For how long would tin protect it, and for how long would it hold together afterward?&lt;/p&gt;&#xA;&lt;p&gt;Don't close it for a lack of research. I did try to google it (including carrying out a search on Scholar) but was unable to find a claim with an authoritative source backing it. I need a good reference&lt;/p&gt;&#xA;" OwnerUserId="22632" LastEditorUserId="22632" LastEditDate="2022-03-25T22:44:19.323" LastActivityDate="2022-03-25T22:44:19.323" Title="How long would it take for a steel can to decompose in a landfill?" Tags="|decomposition|" AnswerCount="2" CommentCount="2" ClosedDate="2022-02-11T17:34:10.697" ContentLicense="CC BY-SA 4.0" />
  <row Id="23511" PostTypeId="1" CreationDate="2022-02-09T02:57:33.553" Score="2" ViewCount="74" Body="&lt;p&gt;From Hurth's book, The Lost Art of Finding Our Way&#xA;, there is a section on Air Mass and Fronts (page 267)&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;On average, since cold air is denser than warm air, the northern stretches of continental landmasses create high-pressure systems, and the warmer maritime air creates low-pressure systems.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;How does density come into play here to create a high-pressure system?&lt;/p&gt;&#xA;" OwnerUserId="26405" LastEditorUserId="26405" LastEditDate="2022-02-14T19:33:15.023" LastActivityDate="2022-03-16T22:05:30.567" Title="Why does warmer maritime air create low pressure systems while continental land masses create high pressure systems?" Tags="|wind|pressure|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23512" PostTypeId="2" ParentId="23510" CreationDate="2022-02-09T03:41:39.327" Score="0" Body="&lt;p&gt;Steel rusts. However this corrosion affects surface in any case; over time takes many years/decades to fully assimilate the whole piece. In a landfill without exposure to oxygen high quality steels may last indefinitely.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2022-02-09T03:41:39.327" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23514" PostTypeId="2" ParentId="22893" CreationDate="2022-02-09T12:38:48.397" Score="2" Body="&lt;p&gt;Regarding 2:&lt;/p&gt;&#xA;&lt;p&gt;The roughness length is dependent on height, eg:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$z_0 = Az\exp(-u(z)/\sigma_u)$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$A=\frac{\sigma_u}{u_*}k$&lt;/span&gt;. (&lt;span class=&quot;math-container&quot;&gt;$k$&lt;/span&gt; is the Von-Karman constant and &lt;span class=&quot;math-container&quot;&gt;$\sigma_u/u(z)$&lt;/span&gt; represents the horizontal turbulent intensity, which basically implies that the roughness length is also very much dependent on wind direction (or sectors). Here you should see roughness length as a coordinate, so as you point out you don't get a value of roughness. None of the 5 values would be correct to use as it is a coordinate.&lt;/p&gt;&#xA;&lt;p&gt;You can estimate the roughness length in many ways. The simplest would be to make a subjective evaluation of the area, or you could use datasets as the CORINE land cover (that's not a good source for roughness in my experience), or you could even measure &lt;span class=&quot;math-container&quot;&gt;$z_0$&lt;/span&gt; by measuring the horizontal turbulent intensity, but that is difficult.&lt;/p&gt;&#xA;&lt;p&gt;When you have your roughness length you can either decide to use the coordinate closest to, or interpolate from the nearest values.&lt;/p&gt;&#xA;&lt;p&gt;Regarding 1:&lt;/p&gt;&#xA;&lt;p&gt;It depends on what you want. I would suggest splitting the ERA5 data into sectors and looking at the sectors' statistics. Also, make a frequency diagram so you can see which wind directions are most common.&lt;/p&gt;&#xA;" OwnerUserId="17522" LastActivityDate="2022-02-09T12:38:48.397" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23515" PostTypeId="1" AcceptedAnswerId="23522" CreationDate="2022-02-09T15:35:38.460" Score="7" ViewCount="1972" Body="&lt;p&gt;Looking at maps of the geological layers in Michigan it looks like an onion starting in the center of the state. Why?&lt;/p&gt;&#xA;&lt;p&gt;Thinking of the recent glacial history of the state that would seem to have created streaks from glacial advance and retreat that would carve valleys or create Moraines. Could it have been a much older meteor strike like with the Sudbury Basin? What could have pushed the layers down so deep for such a wide area?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ndBLL.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ndBLL.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;This ring pattern continues into the Upper Peninsula (see &lt;a href=&quot;https://www.michigan.gov/documents/CGI_1987_Bedrock_Geology_8X11_128879_7.pdf&quot; rel=&quot;noreferrer&quot;&gt;full version&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="462" LastEditorUserId="2470" LastEditDate="2023-01-09T08:43:35.257" LastActivityDate="2023-01-09T08:43:35.257" Title="Why is Michigan Geology Circular?" Tags="|geology|" AnswerCount="2" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23516" PostTypeId="2" ParentId="23510" CreationDate="2022-02-09T22:29:23.637" Score="2" Body="&lt;p&gt;Depends, thin steel like auto sheet metal would mostly be gone in about 20 years buried near the surface in a location with generous rain fall. If thicker, with limited oxygen it could be around for many centuries, eg ship hulls like the Titanic in deep water. About the only data I find shows pit depth of roughly 0.125&amp;quot; in 5 years buried in clay soil. No data for sheet metal because no one buries it deliberately. Thicker steel like pipelines are coated and catholically protected, so any number is only an estimate.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastEditorUserId="8409" LastEditDate="2022-02-10T16:23:34.940" LastActivityDate="2022-02-10T16:23:34.940" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23517" PostTypeId="1" CreationDate="2022-02-10T16:25:49.630" Score="1" ViewCount="22" Body="&lt;p&gt;I recently downloaded Original Product Resolution (OPR) Digital Elevation Model (DEM) data for some analysis. The DEM do not align with any of the other data sets I have for the area. How can I rectify this problem?&lt;/p&gt;&#xA;" OwnerUserId="14152" LastActivityDate="2022-02-10T16:25:49.630" Title="DEM coordinates do not align other data layers" Tags="|remote-sensing|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23518" PostTypeId="1" CreationDate="2022-02-10T19:40:18.070" Score="3" ViewCount="227" Body="&lt;p&gt;I have coordinates obtained from Google Maps (latitude and longitude). I also downloaded a number of NetCDF4 files for different years and months that contain sea surface temperature (SST) from the link below. This data is related to ORAS5 global ocean reanalysis monthly data. &lt;a href=&quot;https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-oras5?tab=form&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-oras5?tab=form&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now I want to extract the sea surface temperature data related to these coordinates from the NetCDF4 files. Datum for Google Maps is WGS84 and Projection is a ”web Mercator”. The projection for the NetCDF4 files is also “Tripolar model grid”.&lt;/p&gt;&#xA;&lt;p&gt;If I need to change the NC files projection to Web Mercator, how is it done?&lt;/p&gt;&#xA;&lt;p&gt;In general, what should be done to correctly extract SST data in NetCDF files for Google Maps coordinates?&lt;/p&gt;&#xA;&lt;p&gt;I also work with Python and MATLAB.&lt;/p&gt;&#xA;" OwnerUserId="26413" LastActivityDate="2022-06-06T16:12:42.070" Title="Extract data from NetCDF file with tripolar projection for lat &amp; long coordinates" Tags="|climate|python|netcdf|coordinate-system|projection|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23519" PostTypeId="1" CreationDate="2022-02-11T04:57:35.923" Score="1" ViewCount="143" Body="&lt;p&gt;How long would it take for a synthetic tire to decompose in a landfill (no oxygen, no sun)? I take it butadiene-styrene rubber is the most prevalent type.&lt;/p&gt;&#xA;&lt;p&gt;Don't close it for a lack of research. I did try to google it (including carrying out a search on Scholar) but was unable to find a claim with an authoritative source backing it. I need a good reference (&lt;a href=&quot;https://www.researchgate.net/publication/325860937_Decomposition_of_Used_Tyre_Rubber_by_Pyrolysis_Enhancement_of_the_Physical_Properties_of_the_Liquid_Fraction_Using_a_Hydrogen_Stream&quot; rel=&quot;nofollow noreferrer&quot;&gt;these&lt;/a&gt; &lt;a href=&quot;https://iopscience.iop.org/article/10.1088/1757-899X/294/1/012064/pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;claims&lt;/a&gt; of &amp;quot;80-100 years&amp;quot;, for instance, don't have any). The objective may be tricky as this website &lt;a href=&quot;https://web.archive.org/web/20190731204948/https://www.co.fresno.ca.us/departments/public-works-planning/divisions-of-public-works-and-planning/resources-and-parks-division/recycling-and-solid-waste-disposal/used-tires&quot; rel=&quot;nofollow noreferrer&quot;&gt;says&lt;/a&gt; &amp;quot;there is no known rate of decomposition for tires&amp;quot;. However, even if it's so, I still need a reference to corroborate that&lt;/p&gt;&#xA;" OwnerUserId="22632" LastEditorUserId="22632" LastEditDate="2022-02-11T05:18:39.010" LastActivityDate="2022-02-11T05:18:39.010" Title="How long would it take for a synthetic tire to decompose in a landfill?" Tags="|decomposition|" AnswerCount="0" CommentCount="5" ClosedDate="2022-02-13T09:03:47.793" ContentLicense="CC BY-SA 4.0" />
  <row Id="23520" PostTypeId="2" ParentId="22662" CreationDate="2022-02-11T17:55:08.987" Score="4" Body="&lt;p&gt;According to the American Geophysical Union and reported at &lt;a href=&quot;https://phys.org/news/2013-04-scientists-dark-lightning-linked-visible.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;phys.org&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Dark lightning is a burst of gamma-rays produced during thunderstorms&#xA;by extremely fast moving electrons colliding with air molecules.&#xA;Researchers refer to such a burst as a terrestrial gamma-ray flash (TGF).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;However, things are not quite so simple.  There are actually several gamma ray phenomena related to thunderstorms.&lt;/p&gt;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://www.nature.com/articles/s42005-019-0168-y&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gamma-ray glow preceding downward terrestrial gamma-ray flash&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Two types of high-energy events have been detected from thunderstorms.&#xA;One is “terrestrial gamma-ray flashes” (TGFs), sub-millisecond&#xA;emissions coinciding with lightning discharges. The other is&#xA;minute-lasting “gamma-ray glows”. Although both phenomena are thought&#xA;to originate from relativistic runaway electron avalanches in strong&#xA;electric fields, the connection between them is not well understood.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The general thought is that electrons are accelerated to high speeds by the extreme electric field present around lighting but that's not yet a completely satisfying explanation.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9MLNa.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9MLNa.png&quot; alt=&quot;Gamma-Ray Factory&quot; /&gt;&lt;/a&gt;&lt;br/&gt;&#xA;Image from &lt;a href=&quot;https://media.nature.com/original/magazine-assets/d41586-021-00395-3/d41586-021-00395-3.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Quest to Understand how Thunderstorms Create Gamma Rays&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Capture of photonuclear neutrons is also a potential source of terrestrial gamma-ray flashes:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;These results challenge TGF theoretical models based on runaway&#xA;electron acceleration. The TGF discharge electric field accelerates&#xA;particles over the large distances for which maximal voltages of&#xA;hundreds of megavolts can be established. The combination of huge&#xA;potentials and large electric fields in TGFs can efficiently&#xA;accelerate particles in large numbers, and we reconsider here the&#xA;photon spectrum and the neutron production by photonuclear reactions&#xA;in the atmosphere. &lt;a href=&quot;https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.106.018501&quot; rel=&quot;nofollow noreferrer&quot;&gt;Terrestrial Gamma-Ray Flashes as Powerful Particle Accelerators&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017GL075552&quot; rel=&quot;nofollow noreferrer&quot;&gt;TGF Afterglows: A New Radiation Mechanism From Thunderstorms&lt;/a&gt; considers three different mechanisms at different time scales.&lt;br&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/zed0Fl.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zed0Fl.png&quot; alt=&quot;Sketch of the distribution of durations of TGFs, TGF afterglows, and gamma ray glows&quot; /&gt;&lt;/a&gt;&lt;br/&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&amp;quot;TGFs originate from cold runaway where thermal electrons accelerate to tens of MeV in the strong electric fields of a propagating leader discharge.&amp;quot;&lt;/li&gt;&#xA;&lt;li&gt;&amp;quot;Glows ... would originate from relativistic runaway electron avalanches (RREA) with feedback of photons and positrons creating new avalanches...&amp;quot;&lt;/li&gt;&#xA;&lt;li&gt;&amp;quot;TGF afterglow ... when photons in the TGF are energetic enough to release neutrons from air molecules by a photonuclear reaction.... During thermalization they can be captured again by nuclei and sometimes with the release of a high-energy photon....&amp;quot;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="18088" LastActivityDate="2022-02-11T17:55:08.987" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23521" PostTypeId="2" ParentId="23351" CreationDate="2022-02-12T01:16:33.557" Score="1" Body="&lt;ol&gt;&#xA;&lt;li&gt;You are adding all the heat in the vertical direction. Since your vertical layers have varying depth (as do most ocean/climate models) you need to account for this. Imagine the surface layer has 10 meters depth, and the second layer 20 meters depth. Both contain 100 Joules of heat each. Then, in the first, you have 10 Joules per meter in the vertical. In the second, you have 20 Joules per meter in the vertical. If you only have the specific heat, or the &amp;quot;per meter&amp;quot; value, you will need to multiply by &amp;quot;how many meters&amp;quot; in each layer. It's the same principle.&lt;/li&gt;&#xA;&lt;li&gt;I'm not aware of a specific OHC routine. But if you are working with NetCDF files, I would strongly recommend you check &lt;a href=&quot;https://code.mpimet.mpg.de/projects/cdo/wiki&quot; rel=&quot;nofollow noreferrer&quot;&gt;CDO&lt;/a&gt;, which makes such multiplications much easier to code, keeping the structure of files and applying conventions. In specific, CDO's &lt;a href=&quot;https://code.mpimet.mpg.de/projects/cdo/embedded/index.html#x1-4410002.8.11&quot; rel=&quot;nofollow noreferrer&quot;&gt;vertical sum operator&lt;/a&gt; uses depths as weights by default.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="8396" LastActivityDate="2022-02-12T01:16:33.557" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23522" PostTypeId="2" ParentId="23515" CreationDate="2022-02-12T18:53:24.240" Score="9" Body="&lt;p&gt;A bedrock geology map will not show surficial deposits such as glacial tills, river sediments, and lake deposits. Bedrock maps have to be constructed using exposed bedrock, borehole data, and roadcuts. My guess is that given the areal extent and depth of glacial deposits that much of the bedrock data is gathered during exploratory drilling for groundwater and mineral exploration and compiled by the state bureau of natural resources (as is done in all US states).&lt;/p&gt;&#xA;&lt;p&gt;Here is a map of the surface geology of Michigan, which, incidentally looks a lot like a topographic map of Michigan, below. This indicates that bedrock is actually hard to find in Michigan.:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/A3qJx.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/A3qJx.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/6pLFV.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6pLFV.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As for why the bedrock geology looks like an &amp;quot;onion&amp;quot;, it is a basic depositional basin in which the center drops slowly and sediments, over time, accumulate with the oldest materials on the outer edge and the youngest in the center. There's nothing special about the Michigan Basin other than the fact that it coincides neatly within the state's southern outline. Below are the other depositional basins of the US:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/5TJXP.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5TJXP.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The only other state with a basin within its borders is Illinois, whose onion-like bedrock structure looks a lot like Michigan's:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/3suZ4.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3suZ4.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Hope that helps!&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2022-02-12T18:53:24.240" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23523" PostTypeId="2" ParentId="23515" CreationDate="2022-02-12T23:50:00.177" Score="6" Body="&lt;p&gt;Not a meteor strike. There are many ways to form circular features on Earth that does not include the Armageddon.&lt;/p&gt;&#xA;&lt;p&gt;As for the Michigan basin, during the Paleozoic is was a somewhat oval sea:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HGuAD.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HGuAD.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Getting an onion-structure of sedimentary rocks is then pretty straightforward. The basin was slowly getting filled by successively younger sediments. In this example, red, then orange, the purple:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4ccG0.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4ccG0.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2022-02-12T23:50:00.177" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23524" PostTypeId="1" CreationDate="2022-02-13T05:38:59.607" Score="5" ViewCount="80" Body="&lt;p&gt;I need to retrieve surface values of a parameter in  high mountainous region that are in hybrid sigma coordinate system.&lt;/p&gt;&#xA;&lt;p&gt;From what I have understood, hybrid sigma coordinate has three layers in the bottom there is pure sigma region which is able to capture the signature of the mountains at the very top of the atmosphere, pure hybrid sigma coordinate in the middle and Pure pressure region at the top.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/1jxAB.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1jxAB.png&quot; alt=&quot;hybrid sigma coordinate&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So since the pure sigma region captures the signature of the mountain, does that mean the lower level values, in this figure (K+1/2) equals to surface values?&lt;/p&gt;&#xA;" OwnerUserId="20906" LastActivityDate="2022-02-13T05:38:59.607" Title="Retrieve surface values in hybrid sigma cordinate system" Tags="|atmosphere|atmosphere-modelling|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23525" PostTypeId="2" ParentId="23132" CreationDate="2022-02-13T17:47:28.347" Score="3" Body="&lt;p&gt;One of the more interesting examples of diamond maintaining high pressure in its lattice is discussed in &lt;a href=&quot;https://space.stackexchange.com/questions/18374/what-forms-of-water-ice-have-been-observed-and-verified-in-the-solar-system/33570#33570&quot;&gt;this answer&lt;/a&gt; from Space Exploration SE. Put briefly, Ice VII inclusions have been found in diamonds at Earth's surface despite this phase of water requiring GPa pressure levels to form. In this case the required pressure must have been inherited within the diamond lattice within which the ice was found, and the calculated pressure from the lattice parameter is indeed between 8 and 11 GPa where Ice VII would be stable.&lt;/p&gt;&#xA;&lt;p&gt;The tendency to maintain pressure internally is not entirely unique to diamond. Any solid formed under pressure can maintain such pressure internally in its crystal lattice. However, if the surrounding pressure is released then the material may also deform to relieve the internal pressure. So, roughly, only an amount of pressure similar to the yield strength (which is typically well below the bulk modulus) is expected to be retained. The mechanics behind this result is described below. For most solids this limit is so low that the inclusions end up in their &amp;quot;normal&amp;quot; low-pressure phases, not very interesting. What is unique about diamond is its much superior strength: [Ruoff&lt;a href=&quot;https://i.stack.imgur.com/EE5iB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;](&lt;a href=&quot;https://doi.org/10.1063/1.326378&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1063/1.326378&lt;/a&gt;) gives a yield strength of 35 GPa, enabling it to rentain enough internal pressure (if it is formed under such pressure) to stabilize Ice VII, perovskite-structured silicates, etc.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Arthur L. Ruoff (1979). &amp;quot;On the yield strength of diamond&amp;quot;.&#xA;&lt;em&gt;Journal of Applied Physics&lt;/em&gt; &lt;strong&gt;50&lt;/strong&gt;, 3354. &lt;a href=&quot;https://doi.org/10.1063/1.326378&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1063/1.326378&lt;/a&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;The pressure's on: How a solid matrix retains pressure ... or not&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Consider a spherical particle of radius &lt;span class=&quot;math-container&quot;&gt;$r_p$&lt;/span&gt; exerting pressure &lt;span class=&quot;math-container&quot;&gt;$P$&lt;/span&gt; on a surrounding solid matrix. In the absence of a counterbalancing pressure from the outside, the imposed pressure from within generates a compressive stress &lt;span class=&quot;math-container&quot;&gt;$\sigma_c$&lt;/span&gt; in the radial direction and a tensile stress &lt;span class=&quot;math-container&quot;&gt;$\sigma_t$&lt;/span&gt; in the two orthogonal directions (along spheres concentric with the particle) through the volune of the surrounding solid. As shown in the picture below, both components decrease with the cube of the distance from the particle, and so have maximum magnitude at the particle surface. There the negative compressive stress is &lt;span class=&quot;math-container&quot;&gt;$-P$&lt;/span&gt; and the positive tensile stress is &lt;span class=&quot;math-container&quot;&gt;$+P/2$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ksIa7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ksIa7.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;We can apply the Von Mises yield criterion which states that the surrounding matrix yields, thus reducing the retained pressure, when&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$(\sigma_1-\sigma_2)^2+(\sigma_2-\sigma_3)^2+(\sigma_3-\sigma_1)^2\ge2(YS)^2$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$\sigma_1,\sigma_2,\sigma_3$&lt;/span&gt; are the three orthogonal principal components of the stress tensor. Here &lt;span class=&quot;math-container&quot;&gt;$\sigma_1=\sigma_c=-P$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\sigma_2=\sigma_3=\sigma_t=+P/2$&lt;/span&gt;, from which the yield criterion then becomes&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$P\ge(2/3)(YS)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;For a diamond lattice with a yield strength of 35 GPa this means the diamond can sustain a pressure up to 23 GPa, as quoted in the main text, around an Ice VII inclusions, whereas most other minerals would have yield stresses well below 1 GPa and thus fail to retain enough pressure to sustain Ice VII or other GPa-pressure phase inclusions.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2023-01-23T23:13:10.657" LastActivityDate="2023-01-23T23:13:10.657" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23526" PostTypeId="1" CreationDate="2022-02-14T15:15:23.063" Score="4" ViewCount="306" Body="&lt;p&gt;For example :&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The center of Africa lies in the Equatorial region and yet, does not have tropical rainforests all the way across.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The island of Madagascar has two different biomes&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Since altitude and latitude doesn't seem to be the reason behind these anomalies, what other factors affect the biome of these places?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/29GaT.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/29GaT.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26426" LastEditorUserId="6467" LastEditDate="2022-02-15T01:24:14.757" LastActivityDate="2022-02-16T03:18:33.593" Title="What is the reason behind some of the biome anomalies in Africa?" Tags="|meteorology|temperature|geography|ecology|altitude|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23527" PostTypeId="1" CreationDate="2022-02-14T15:45:22.130" Score="4" ViewCount="24" Body="&lt;p&gt;In the Sea-Ice models they use the Sea-Ice thickness categories. An example is the SIS model of BCC CSM (&lt;a href=&quot;http://forecast.bcccsm.ncc-cma.net/web/?ChannelID=37&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://forecast.bcccsm.ncc-cma.net/web/?ChannelID=37&lt;/a&gt;, &lt;a href=&quot;https://www.gfdl.noaa.gov/sea-ice-simulator/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.gfdl.noaa.gov/sea-ice-simulator/&lt;/a&gt;). Is it meant by 5 Sea-Ice thickness categories that there are only 5 discretized thicknesses the Sea-Ice can take, or are the categories separators for treating the Sea-Ice differently in each category? (if so, why would they treat Sea-Ice in each category differently?)&lt;/p&gt;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="26428" LastEditorUserId="26428" LastEditDate="2022-02-14T16:16:43.587" LastActivityDate="2022-02-14T16:16:43.587" Title="Sea-Ice thickness categories" Tags="|sea-ice|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23529" PostTypeId="1" CreationDate="2022-02-14T20:15:33.223" Score="4" ViewCount="35" Body="&lt;p&gt;I am not sure if this question makes sense, it is completely out of the blue. Over a large range of latitudes, we have 4 distinct seasons and repeat again and again the next years. Even in the poles, we have distinct summer and winter. I believe many places in the tropics also have wet and dry seasons (not an expert).&lt;/p&gt;&#xA;&lt;p&gt;So now the question comes: Is there any place on Earth that does not have a sub-annual cyclical pattern?&#xA;It seems there are some really wet tropical rainforests that don't have season, do they &lt;strong&gt;&amp;quot;really&amp;quot;&lt;/strong&gt; operate the same all year long? Do the organisms living inside rainforests also show no consistent behavioral cycles (e.g., like hibernation, mating seasons in other places)?&lt;/p&gt;&#xA;" OwnerUserId="3241" LastActivityDate="2022-02-14T20:15:33.223" Title="Is there any place on Earth that does not have a &quot;sub-annual&quot; cycle/season?" Tags="|climate|geography|seasons|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23530" PostTypeId="2" ParentId="23511" CreationDate="2022-02-14T21:21:35.523" Score="1" Body="&lt;p&gt;I ended up asking him directly:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;It's a bit of a simplification of what happens.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;You can picture a large column of air stretching into the sky.   To a first approximation, we live an equal pressure environment, which is why the air pressure is about 1013 millibars both in summer and in winter , as the surface temperature changes.   This column of air that stretches into the sky expands and contracts, depending on the temperature.    It expands in warmer temperatures and contracts in smaller temperatures.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The second order effect is associated with what you might expect from buoyancy.   A hot air balloon rises because the warm air is less dense than the surrounding air, and by Archimedes' principle.  So, hot air tends to be less dense than cool air.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The way I understand is you can imagine that warm air would cause the column of air to expand, and thus create a lower pressure than where it's colder. Since air goes from high pressure to low pressure, there would be a vacuum.&lt;/p&gt;&#xA;" OwnerUserId="26405" LastActivityDate="2022-02-14T21:21:35.523" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23531" PostTypeId="1" AcceptedAnswerId="23532" CreationDate="2022-02-15T11:39:00.097" Score="7" ViewCount="86" Body="&lt;p&gt;Changes in oceanic oxygen isotope ratios (&lt;sup&gt;18&lt;/sup&gt;O to &lt;sup&gt;16&lt;/sup&gt;O) are reflected in the shells of ancient foraminifera.&lt;/p&gt;&#xA;&lt;p&gt;However, I have not read of diatom shells being used, despite the fact that they were (and are) at least as abundant, correct?&lt;/p&gt;&#xA;&lt;p&gt;I know that diatoms use silica instead of calcium carbonate... Does that mean anything?  Are diatoms using already-ancient sand to make their shells, rather than creating their own from newly-formed molecules, like foraminiferae do?  Does that mean any CaCO&lt;sub&gt;3&lt;/sub&gt;-using creature can be used as an ancient temperature proxy, since they always utilize the oxygen isotopes available in their time and place?&lt;/p&gt;&#xA;&lt;p&gt;Can diatoms' remains be examined for any ancient information?  They are so abundant...&lt;/p&gt;&#xA;" OwnerUserId="20985" LastEditorUserId="18081" LastEditDate="2022-02-16T18:19:08.220" LastActivityDate="2022-02-16T18:19:08.220" Title="Why aren't diatoms' shells used as a temperature proxy, but foraminifera shells are?" Tags="|climate-change|oceanography|paleoclimatology|paleontology|climatology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23532" PostTypeId="2" ParentId="23531" CreationDate="2022-02-15T17:28:36.893" Score="7" Body="&lt;p&gt;Lacustrine diatoms are used extensively as reliable conventional proxies in Holocene (within the last 10,000 years) paleoclimate studies. According to &lt;a href=&quot;https://www.researchgate.net/publication/236156990_Problems_and_potentialities_of_using_diatoms_as_paleoclimatic_indicators_in_Central_Argentina&quot; rel=&quot;noreferrer&quot;&gt;this 2010 paper&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;em&gt;(paleoclimate) Reconstructions based on all these methods rely on the general assumption that the environmental requirements of the fossil&#xA;diatom taxa used as bioindicators have remained constant during the&#xA;period considered and, consequently, are similar to those of their&#xA;closest living representatives. In this way, the environmental&#xA;information obtained from living organisms can be used as modern&#xA;analogous and extrapolated to the fossil record, particularly in&#xA;Quaternary research&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;As abundant as they are in living form, diatoms are generally poorly (and unreliably) preserved in an older oceanic fossil record. Importantly, they evolve rather quickly making tracking chemical changes in a single species over time and space impossible. Bulk chemistries may be obtained from fossilized silicic masses and serve as rough indicators of overall diatom abundance and thus system health.&lt;/p&gt;&#xA;&lt;p&gt;They are, however, used in novel ways: some diatoms live exclusively in sea ice and can be used to assess duration and distribution of that sea ice, itself a record of sea surface temperature (SST):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://reader.elsevier.com/reader/sd/pii/S1873965217301391?token=6C5E95759274F913063C4CB91E8A2E5F1B123AD9F314F73FC3445ADF3D93BE3E371645D38D2E1F16C62F6420E808DA19&amp;amp;originRegion=us-east-1&amp;amp;originCreation=20220215171602&quot; rel=&quot;noreferrer&quot;&gt;Diatoms in Arctic regions: Potential tools to decipher environmental changes&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://tos.org/oceanography/assets/docs/33-2_leventer.pdf&quot; rel=&quot;noreferrer&quot;&gt;SIDEBAR. Diatoms as Sea Ice Proxies&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;By contrast, forams are well preserved in the fossil record, have a well calibrated evolutionary record, and as carbonates, contain important isotopes whose ratios are sensitive to SST.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastEditorUserId="7333" LastEditDate="2022-02-15T17:37:01.357" LastActivityDate="2022-02-15T17:37:01.357" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23533" PostTypeId="2" ParentId="17997" CreationDate="2022-02-15T21:27:59.617" Score="1" Body="&lt;p&gt;There is no such thing as a mantle of O&lt;sub&gt;3&lt;/sub&gt; in the atmosphere, it is more prudent to call it ozonosphere. Ozone is produced by electrical discharges, you can relate to its smell if you leave an electrical motor spinning for some time or after thunderstorms. But mostly it is produced by ultraviolet light hitting Oxygen (O&lt;sub&gt;2&lt;/sub&gt;)! You see, that is the O&lt;sub&gt;2&lt;/sub&gt; that protects humans from ultraviolet light and ozone will be produced more whenever light from the sun contacts oxygen.&#xA;On the other hand, if you are actually worried about ozone per se, jets fly at the altitude of ozonosphere where the ratio of Ozone to Oxygen gas is higher. These jets consume tonnes of Ozone to burn querosene in their engines in flight. Other free radicals can also react with ozone, but it is itself a free radical, and it can react with itself on certain energy levels.&lt;/p&gt;&#xA;" OwnerUserId="26436" LastEditorUserId="2470" LastEditDate="2022-02-16T00:13:54.933" LastActivityDate="2022-02-16T00:13:54.933" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23534" PostTypeId="2" ParentId="18591" CreationDate="2022-02-15T22:02:18.223" Score="-1" Body="&lt;p&gt;Human activity can change weather locally, for example if you live in lower floors in a hotel room besides a hectic highway it would certainly be cooler whenever traffic is lower because of the combustion engines, but on other level certainly trees grow faster closer to hectic highways from car emissions of CO&lt;sub&gt;2&lt;/sub&gt; and thus provide more canopy and in some sense change the pavement habitat a little bit.. But usually one ought to think that the city exists somewhere because the weather allows it and poor human planning and projects are defeated by weather agents along the way in history.&lt;/p&gt;&#xA;&lt;p&gt;I am sure there are other examples of local weather being affected by concrete, i.e. city formation, such as thermal inversion.&#xA;But remember that the atmosphere behaves like a liquid and is constantly being moved about by hydrodynamical forces and any particles tend to precipitate or be blown away.&lt;/p&gt;&#xA;&lt;p&gt;Not sure about what you said about ozone, though. Ozone is primarily produced by ultraviolet light from the sun. Sun ultraviolet rays hit oxygen and produce ozone so oxygen will protect humans from ultraviolet light whenever sun rays contact oxygen, not at night obviously and less in winter times.&lt;/p&gt;&#xA;" OwnerUserId="26436" LastEditorUserId="2470" LastEditDate="2022-02-16T00:15:18.873" LastActivityDate="2022-02-16T00:15:18.873" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23536" PostTypeId="1" CreationDate="2022-02-15T23:45:03.953" Score="6" ViewCount="1436" Body="&lt;p&gt;Small localized deposits of 60%wt Uranium were found in Cigar Lake, Canada during the ‘90’s. If an exposed rich deposit like this were covered by sedimentary carbon from eroding rock, layering graphite on the uranium, would a fission reactor form naturally? Could it generate power in the kilowatt range as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Oklo_Mine&quot; rel=&quot;noreferrer&quot;&gt;Oklo reactor&lt;/a&gt; is thought to have done?&lt;/p&gt;&#xA;" OwnerUserId="26437" LastEditorUserId="18081" LastEditDate="2022-02-16T09:40:24.063" LastActivityDate="2022-02-16T09:40:24.063" Title="Could a natural fission reactor form in Cigar Lake?" Tags="|radioactivity|uranium|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="23538" PostTypeId="2" ParentId="23536" CreationDate="2022-02-16T04:50:40.523" Score="8" Body="&lt;p&gt;Given that the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cigar_Lake_Mine&quot; rel=&quot;noreferrer&quot;&gt;Cigar Lake&lt;/a&gt; &lt;a href=&quot;https://miningdataonline.com/property/26/Cigar-Lake-Mine.aspx&quot; rel=&quot;noreferrer&quot;&gt;uranium deposit&lt;/a&gt; is already buried beep, at 450 m below the surface, a &amp;quot;sedimentary carbon&amp;quot; deposit will not be deposited anywhere close to the uranium deposit. The age of the deposit is estimated to be 1.3 Ga (billion years).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Due to natural containment and lack of any traces of radioactive elements on the surface, the deposit is used as an example of an effective natural deep geological repository.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;There are &lt;a href=&quot;https://nuclearsafety.gc.ca/eng/uranium/mines-and-mills/nuclear-facilities/cigar-lake/index.cfm&quot; rel=&quot;noreferrer&quot;&gt;no open pits&lt;/a&gt; at &lt;a href=&quot;https://www.geologyforinvestors.com/cigar-lake-mine-the-worlds-largest-uranium-producer/&quot; rel=&quot;noreferrer&quot;&gt;Cigar Lake&lt;/a&gt;,&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kyYcw.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kyYcw.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Infrastructure at the site includes an underground mine; freezing plants and associated freeze pads; ore processing and load out; water treatment; mine rock storage pads; temporary waste storage; warehouses; worker camp; and office and administrative buildings.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Also, given the relatively flat topography of northern Saskatchewan, where Cigar Lake is located, carbon sediments are unlikely to be deposited at anywhere near the uranium deposit and mine.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-02-16T04:50:40.523" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23539" PostTypeId="2" ParentId="22397" CreationDate="2022-02-16T15:01:22.690" Score="4" Body="&lt;p&gt;Dust storms or haboobs traveling over seas and oceans is a common phenomenon, and will occur in any desert (having loose soil and sand) with a coastline. Such deserts include the Sahara, the Arabian desert, parts of the deserts of Australia, etc.&lt;/p&gt;&#xA;&lt;p&gt;Haboobs are caused by collapsing thunderstorms, when the downdraft of cooler air crashes on the ground and blow away the loose and dry topsoil. The conditions required for the formation of haboobs is those required for the formation of thunderstorms in a desert, i.e., solar insolation heating up surface air and creates an updraft of hot air, which cools down in the higher altitudes and creates a downdraft over time, slamming a column of cooler air on the dry desert surface. This downdraft then carries away the blown dust in directions determined by the air pressure difference. In coastal deserts, the blown dust may often be carried over to the sea or ocean.&lt;/p&gt;&#xA;&lt;p&gt;In fact, dust storms, or more broadly dust clouds, crossing oceans constitutes one of the most critical processes shaping up the current environment of the earth. This particular process is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Saharan_Air_Layer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Saharan air layer&lt;/a&gt;, which carries tens of millions of tons of sand and minerals from the Sahara over the Atlantic ocean all the way to the Amazons in South America. &lt;a href=&quot;https://www.nasa.gov/content/goddard/nasa-satellite-reveals-how-much-saharan-dust-feeds-amazon-s-plants&quot; rel=&quot;nofollow noreferrer&quot;&gt;The nutrients play a key role in fertilizing the Amazon rain forest&lt;/a&gt;. &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2007GL031538&quot; rel=&quot;nofollow noreferrer&quot;&gt;The particles in the dust cloud cools the Atlantic ocean&lt;/a&gt;, and &lt;a href=&quot;https://archive.org/details/impactsaharanair00veld&quot; rel=&quot;nofollow noreferrer&quot;&gt;hinders the formation and intensification of cyclones in the Atlantic&lt;/a&gt;. This process often creates gigantic dust storms or dust cloud spread over thousands of kilometers across, clearly &lt;a href=&quot;https://www.youtube.com/watch?v=ygulQJoIe2Y&quot; rel=&quot;nofollow noreferrer&quot;&gt;observable and studied using satellite imagery&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Some of the news related to recent such Saharan dust storms crossing the Atlantic, with associated imagery:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.independent.co.uk/climate-change/sahara-dust-storm-atlantic-image-b1996665.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Satellite images show 4,000km-long Saharan dust cloud across Atlantic Ocean&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.theatlantic.com/science/archive/2020/06/saharan-dust-storms-giving-earth-life/613441/&quot; rel=&quot;nofollow noreferrer&quot;&gt;A Giant Dust Storm Is Heading Across the Atlantic&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.severe-weather.eu/news/new-saharan-dust-cloud-atlantic-united-states-forecast-fa/&quot; rel=&quot;nofollow noreferrer&quot;&gt;A new large Saharan dust cloud is moving over the Atlantic Ocean, forecast to reach the Caribbean and the southeastern United States by the end of the week&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;However, as can be observed from the images of the Saharan dust storms, formation of shelf clouds over the dust storms are rare for them. This is because the formation of such clouds require cooler temperature and sufficient moisture, which would not be available in the usual Saharan dust storms over the Atlantic. From the &lt;a href=&quot;https://en.wikipedia.org/wiki/Arcus_cloud&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia page&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;They most frequently form along the leading edge or gust fronts of thunderstorms; some of the most dramatic arcus formations mark the gust fronts of derecho-producing convective systems. Roll clouds may also arise in the absence of thunderstorms, forming along the shallow cold air currents of some sea breeze boundaries and cold fronts.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The formation of &lt;a href=&quot;https://en.wikipedia.org/wiki/Cold_front&quot; rel=&quot;nofollow noreferrer&quot;&gt;cold fronts&lt;/a&gt; is often associated with Australian dust storms (&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/034181629500026O&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;https://rmets.onlinelibrary.wiley.com/doi/abs/10.1002/joc.1072&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;). And such storms occurring in especially the north-western coastal deserts of Australia will have adequate moisture from the Indian Ocean and the cooler air required. Due to this, such spectacular but rare phenomenon is likely to occur more in the Australian deserts compared to the Saharan or the Arabian deserts, which are often too dry for the formation of such clouds.&lt;/p&gt;&#xA;&lt;p&gt;So the conditions required for the occurrence of this phenomenon are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;a coastal &lt;a href=&quot;https://en.wikipedia.org/wiki/Desert_climate#Hot_desert_climates&quot; rel=&quot;nofollow noreferrer&quot;&gt;hot desert&lt;/a&gt; with loose surface soil,&lt;/li&gt;&#xA;&lt;li&gt;temperature not hot enough so that the dust storm does not lift over cooler &lt;a href=&quot;https://en.wikipedia.org/wiki/Marine_layer&quot; rel=&quot;nofollow noreferrer&quot;&gt;marine air&lt;/a&gt; and becomes a dust cloud, as happens for the &lt;a href=&quot;https://en.wikipedia.org/wiki/Saharan_Air_Layer#Creation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Saharan air layer&lt;/a&gt;, where even the temperature of the downdraft is so high that the resulting dust storm lifts over the cooler Atlantic marine air and becomes a dust cloud.&lt;/li&gt;&#xA;&lt;li&gt;just enough moisture in the environment for the formation of &lt;a href=&quot;https://en.wikipedia.org/wiki/Arcus_cloud&quot; rel=&quot;nofollow noreferrer&quot;&gt;shelf clouds&lt;/a&gt;, but not enough to cause rainfall in the thunderstorm, thereby dissipating the dust storm and the clouds over them.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="23207" LastEditorUserId="23207" LastEditDate="2022-02-16T15:19:35.047" LastActivityDate="2022-02-16T15:19:35.047" CommentCount="16" ContentLicense="CC BY-SA 4.0" />
  <row Id="23540" PostTypeId="1" AcceptedAnswerId="23543" CreationDate="2022-02-16T18:55:50.843" Score="8" ViewCount="837" Body="&lt;p&gt;The White Cliffs of Dover are mostly chalk but there are regularly spaced horizontal lines of flint.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3fthX.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3fthX.jpg&quot; alt=&quot;White Cliffs of Dover, chalk with lines of flint&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I understand how the chalk and flint layers are formed independently (from &lt;a href=&quot;https://en.wikipedia.org/wiki/White_Cliffs_of_Dover#Geology&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;) but I haven't been able to find any information on why they formed in these regular stripes.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JDmlw.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JDmlw.jpg&quot; alt=&quot;flint layer close up&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Would coccoliths alone pile up for a long period of time, then sponges/siliceous plankton pile up for a much shorter time, then back to the coccoliths alone piling up and so on? ... seems very implausible.&lt;/p&gt;&#xA;&lt;p&gt;Sorry if this is a very basic question but this has been bugging me ever since I visited over 10 years ago! :D&lt;/p&gt;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="26440" LastEditorUserId="26440" LastEditDate="2022-02-16T21:50:37.543" LastActivityDate="2022-02-18T19:48:11.777" Title="How did the Cliffs of Dover form flint in regular stripes?" Tags="|geology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23541" PostTypeId="1" CreationDate="2022-02-16T20:32:48.570" Score="4" ViewCount="109" Body="&lt;p&gt;Over the last 30 years, Foehn winds have led to wildfires affecting densely populated areas of the California coast. They're called Diablo winds in the north, and Santa Ana winds in the south.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://pbs.twimg.com/media/DroyKoaVYAAEYCT?format=jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Paradise firestorm (aka the Camp Fire)&lt;/a&gt;, &lt;a href=&quot;https://s.hdnux.com/photos/01/07/55/00/18796599/10/rawImage.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kincade fire&lt;/a&gt; (and consequential &lt;a href=&quot;https://www.sfgate.com/california-wildfires/article/PG-E-power-outage-800-000-customers-length-number-14501984.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;power shutoffs&lt;/a&gt;), the &lt;a href=&quot;https://imengine.prod.srp.navigacloud.com/?uuid=979063c4-32d3-50e7-9ba6-c03b0ee9148b&amp;amp;type=primary&amp;amp;q=72&amp;amp;width=1024&quot; rel=&quot;nofollow noreferrer&quot;&gt;LNU&lt;/a&gt; and &lt;a href=&quot;https://s.hdnux.com/photos/01/13/52/17/19833846/6/rawImage.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;SCU&lt;/a&gt; Lightning Complex fires, the &lt;a href=&quot;https://i2.wp.com/revealnews.org/wp-content/uploads/2016/10/AP_911020077.jpg?fit=3000%2C1992&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oakland firestorm of 1991&lt;/a&gt;, the &lt;a href=&quot;https://ca-times.brightspotcdn.com/dims4/default/3511d53/2147483647/strip/true/crop/3000x2000+0+0/resize/1486x991!/quality/90/?url=https%3A%2F%2Fcalifornia-times-brightspot.s3.amazonaws.com%2Fcb%2Fa9%2F7de2b0074bdb8283ca4b6a8219cc%2Fla-photos-1staff-615811-me-bobcat-30-rcg.JPG&quot; rel=&quot;nofollow noreferrer&quot;&gt;2020 Bobcat Fire&lt;/a&gt; and &lt;a href=&quot;https://live.staticflickr.com/3446/3869565211_b248ddc35e_b.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;2009 Station Fire&lt;/a&gt; in the San Gabriel Mountains; firestorms in &lt;a href=&quot;https://www.redzone.co/wp-content/uploads/2019/02/woolsey-fire-near-the-shore.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Malibu (Woolsey Fire)&lt;/a&gt;, the &lt;a href=&quot;https://ktla.com/wp-content/uploads/sites/4/2019/10/gettyimages-1175341969.jpg?w=2560&amp;amp;h=1440&amp;amp;crop=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;San Fernando Valley (Saddleridge Fire)&lt;/a&gt;, and in San Diego's East County region (&lt;a href=&quot;https://ca-times.brightspotcdn.com/dims4/default/49ac9af/2147483647/strip/true/crop/1968x1312+0+0/resize/1486x991!/quality/90/?url=https%3A%2F%2Fcalifornia-times-brightspot.s3.amazonaws.com%2F99%2F7e%2F56db1fac1ecb15ce685836125112%2Fsdut-the-a-wall-of-fire-surrounds-sc-20160905&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cedar Fire 2003&lt;/a&gt; and &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/f/fd/Witch_Creek_Fire_at_night.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Witch Fire 2007&lt;/a&gt;), the list goes on, and on, and on.&lt;/p&gt;&#xA;&lt;p&gt;It wasn't until embarrassingly late in life that I realized the Diablo/Santa Ana winds, the catalyst for devastating wildfires, the reason for the CA coast's warmest months being October and November, are the same kinds of winds that I had known about since I was young: the Chinook winds in southern Alberta, aka going from &lt;a href=&quot;https://weatherspark.com/h/d/145468/2022/2/4/Historical-Weather-on-Friday-February-4-2022-at-Calgary-International-Alta.;-Canada#Figures-Temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;-11°C to 6°C in less than three hours.&lt;/a&gt; (Note how the wind direction switches from &lt;a href=&quot;https://weatherspark.com/h/d/145468/2022/2/4/Historical-Weather-on-Friday-February-4-2022-at-Calgary-International-Alta.;-Canada#Figures-WindDirection&quot; rel=&quot;nofollow noreferrer&quot;&gt;northerly to west-southwest&lt;/a&gt; between 09:00-10:00 MST.) The excellent &lt;a href=&quot;https://www.eoas.ubc.ca/courses/atsc113/flying/met_concepts/02-met_concepts/02e-shear_at_aerodromes/downslope_windstorms.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;ATSC 113 course page at UBC&lt;/a&gt; explains it better than I can.&lt;/p&gt;&#xA;&lt;p&gt;We can get Foehn winds along coastal sections in the winter, called Squamish winds (Arctic outflow winds). But can summer Foehn winds be experienced in places near the Coast Mountains or Cascades in Oregon, Washington state, and BC? Can cities like Seattle, Yakima, Spokane, Vancouver or Kelowna get something along the lines of Diablo or Santa Ana winds? If not, why?&lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2022-02-16T20:32:48.570" Title="Do warm-season Foehn winds occur in the Pacific Northwest?" Tags="|meteorology|wind|mountains|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23542" PostTypeId="2" ParentId="22661" CreationDate="2022-02-17T12:14:36.330" Score="3" Body="&lt;p&gt;In New Zealand, heavy rainfall is defined as &lt;a href=&quot;https://niwa.co.nz/natural-hazards/extreme-weather-heavy-rainfall&quot; rel=&quot;nofollow noreferrer&quot;&gt;rainfall greater than 100 mm in 24 hours&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://water.usgs.gov/edu/activity-howmuchrain-metric.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;rainfall categories defined in USGS&lt;/a&gt; are as following:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Slight rain: Less than 0.5 mm per hour.&lt;/li&gt;&#xA;&lt;li&gt;Moderate rain: Greater than 0.5 mm per hour, but less than 4.0 mm per hour.&lt;/li&gt;&#xA;&lt;li&gt;Heavy rain: Greater than 4 mm per hour, but less than 8 mm per hour.&lt;/li&gt;&#xA;&lt;li&gt;Very heavy rain: Greater than 8 mm per hour.&lt;/li&gt;&#xA;&lt;li&gt;Slight shower: Less than 2 mm per hour.&lt;/li&gt;&#xA;&lt;li&gt;Moderate shower: Greater than 2 mm, but less than 10 mm per hour.&lt;/li&gt;&#xA;&lt;li&gt;Heavy shower: Greater than 10 mm per hour, but less than 50 mm per hour.&#xA;Violent shower: Greater than 50 mm per hour.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.imdpune.gov.in/Weather/Reports/glossary.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here is the glossary of rainfall intensity&lt;/a&gt; (among other things) as defined and used by the Indian Meteorological Department:&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th&gt;&lt;/th&gt;&#xA;&lt;th&gt;&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;No rain&lt;/td&gt;&#xA;&lt;td&gt;Rainfall amount realised in a day is 0.0 mm&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Trace&lt;/td&gt;&#xA;&lt;td&gt;Rainfall amount realised in a day is between 0.01 to 0.04 mm&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Very light rain&lt;/td&gt;&#xA;&lt;td&gt;Rainfall amount realised in a day is between 0.1 to 2.4 mm&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Light rain&lt;/td&gt;&#xA;&lt;td&gt;Rainfall amount realised in a day is between 2.5 to 7.5 mm&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Moderate Rain&lt;/td&gt;&#xA;&lt;td&gt;Rainfall amount realised in a day is between 7.6 to 35.5 mm&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Rather Heavy&lt;/td&gt;&#xA;&lt;td&gt;Rainfall amount realised in a day is between 35.6 to 64.4 mm&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Heavy rain&lt;/td&gt;&#xA;&lt;td&gt;Rainfall amount realised in a day is between 64.5 to 124.4 mm&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Very Heavy rain&lt;/td&gt;&#xA;&lt;td&gt;Rainfall amount realised in a day is between 124.5 to 244.4 mm&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Extremely Heavy rain&lt;/td&gt;&#xA;&lt;td&gt;Rainfall amount realised in a day is more than or equal to 244.5 mm&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Exceptionally Heavy Rainfall&lt;/td&gt;&#xA;&lt;td&gt;This term is used when the amount realised in a day is a value near about the highest recorded rainfall at or near the station for the month or season. However, this term will be used only when the actual rainfall amount exceeds 12 cm.&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Rainy Day&lt;/td&gt;&#xA;&lt;td&gt;Rainfall amount realised in a day is 2.5 mm or more.&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;&#xA;&lt;p&gt;In Taiwan, &lt;a href=&quot;https://www.cwb.gov.tw/V8/E/P/Warning/W26.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;as mentioned in the question, the rainfall categories are&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Heavy Rain: 24-hour accumulated rainfall exceeds 80 millimeters, or 1-hour rainfall exceeds 40 millimeters.&lt;/li&gt;&#xA;&lt;li&gt;Extremely Heavy Rain: 24-hour accumulated rainfall exceeds 200 millimeters, or 3-hour accumulated rainfall exceeds 100 millimeters.&lt;/li&gt;&#xA;&lt;li&gt;Torrential Rain: 24-hour accumulated rainfall exceeds 350 millimeters, or 3-hour accumulated rainfall exceeds 200 millimeters.&lt;/li&gt;&#xA;&lt;li&gt;Extremely Torrential Rain: 24-hour accumulated rainfall exceeds 500 millimeters.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;From the above examples, it is clear that there is no standard terminology for rainfall intensity used worldwide, unlike the Saffir–Simpson hurricane scale. Various quantities of rainfall are given various monikers by the meteorological departments of the local governments based on the climate, geography and drainage of the area under consideration.&lt;/p&gt;&#xA;&lt;p&gt;Further, the words in rainfall classification are so widely used that it is perhaps not possible to standardize them even if one wants to. A typical daily rainfall in &lt;a href=&quot;https://en.wikipedia.org/wiki/Cherrapunji&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cherrapunji&lt;/a&gt; would be considered as heavy rain in &lt;a href=&quot;https://weather-and-climate.com/average-monthly-precipitation-Rainfall,Riyadh,Saudi-Arabia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Riyadh&lt;/a&gt;, for example. On the other hand, Categories 1, 2, 3, 4 and 5 in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Saffir%E2%80%93Simpson_scale&quot; rel=&quot;nofollow noreferrer&quot;&gt;Saffir–Simpson scale&lt;/a&gt; did not have any meaning before being defined. Whereas, 'moderate', 'heavy', 'torrential', etc. are widely used words whose meaning varies from region to region when used in association to rainfall quantity.&lt;/p&gt;&#xA;" OwnerUserId="23207" LastActivityDate="2022-02-17T12:14:36.330" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23543" PostTypeId="2" ParentId="23540" CreationDate="2022-02-17T16:54:01.413" Score="5" Body="&lt;p&gt;Flint formation is complex, and the details still subject of research and debate.&lt;/p&gt;&#xA;&lt;p&gt;The main factor is not a change in the relative proportion of siliceous and carbonate plankton, but the influence of chemical processes in the sediment after deposition. The flints precipitated where carbonate was dissolved. The dissolution occurred at the boundary between oxygenated water moving from the surface downwards and anoxic water rich in hydrogen sulphide from decomposing organic matter (the redox boundary). The reaction between oxygen and sulphide makes the water acidic at the boundary and this allows the carbonate to dissolve. Silica, which is in solution throughout the chalk, is in a state where it is precipitated from water with high carbonate concentrations, so flint forms at the redox boundary, typically between 5 and 10 metres below the sea bed.&lt;/p&gt;&#xA;&lt;p&gt;The repetitive layering of bands seen in the cliffs may be influenced by cycles in the rate of sedimentation, with bands forming when sedimentation paused and the position of the redox boundary was stable.  A secondary factor may be changes in the chalk matrix that influenced flow rates of water, and hence the redox boundary location. These changes are the result of changes in sediment supply, and bioturbation by burrowing animals at the sea bed.&lt;/p&gt;&#xA;&lt;p&gt;The process is described in a paper by &lt;a href=&quot;https://books.google.co.uk/books?id=4IjCPNkBnqMC&amp;amp;pg=PA43&amp;amp;source=gbs_toc_r&amp;amp;cad=3#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;Clayton, 1986&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastEditorUserId="21672" LastEditDate="2022-02-18T16:32:03.343" LastActivityDate="2022-02-18T16:32:03.343" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23544" PostTypeId="1" CreationDate="2022-02-18T13:04:34.573" Score="4" ViewCount="93" Body="&lt;p&gt;A popular website for observing wind-speed showed the following distribution over the North Sea 2022-02-18 around the same time that storm Eunice was due to hit the UK.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/p6cur.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/p6cur.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;There is some kind of long thin region extending out from the firth of Forth of relatively low wind-speed.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question&lt;/strong&gt;: What is this phenomenon?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="26456" LastActivityDate="2022-02-22T10:12:44.397" Title="Odd wind-speed distribution over North Sea" Tags="|meteorology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23547" PostTypeId="1" CreationDate="2022-02-19T06:34:59.683" Score="4" ViewCount="103" Body="&lt;p&gt;In the context of sediment deformation, why are some structures called &lt;em&gt;load and founder&lt;/em&gt; structures? I know what a load is, but what is a founder?&lt;/p&gt;&#xA;&lt;p&gt;I read it in Sam Boggs, Jr's &lt;em&gt;Principles of Sedimentology and Stratigraphy&lt;/em&gt; and can't figure out why the author uses that word. He lists several deformation structures as being load and founder structures: convolute bedding &amp;amp; lamination, flame structures, ball &amp;amp; pillow structures, and load casts.&lt;/p&gt;&#xA;&lt;p&gt;A few ideas for &lt;em&gt;founder&lt;/em&gt; come to mind:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;the foundering of a ship filling with water&lt;/li&gt;&#xA;&lt;li&gt;the founding of metal (liquifying &amp;amp; casting it; seems vaguely applicable)&lt;/li&gt;&#xA;&lt;li&gt;&lt;em&gt;found&lt;/em&gt; as in the root of &lt;em&gt;foundation&lt;/em&gt; (Perhaps the &lt;em&gt;load&lt;/em&gt; sediment overlies the &lt;em&gt;founder&lt;/em&gt;?)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Sorry my research turned up flat. My instructors don't know, and the only hint I've found online is the &lt;a href=&quot;https://www.britannica.com/science/sedimentary-rock/Sedimentary-structures&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Encyclopedia Britannica&lt;/em&gt;&lt;/a&gt; using the phrase in the same context, but they too do not mention it again.&lt;/p&gt;&#xA;" OwnerUserId="26459" LastActivityDate="2022-02-20T17:54:55.390" Title="What does the term &quot;founder&quot; in &quot;load and founder structure&quot; mean in sedimentary geology?" Tags="|sedimentology|stratigraphy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23549" PostTypeId="2" ParentId="23547" CreationDate="2022-02-20T17:54:55.390" Score="2" Body="&lt;p&gt;If we look at definitions online, at Merriam-Webster online we find this as one of the options:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.merriam-webster.com/dictionary/founder#:%7E:text=3,become%20submerged%20%3A%20SINK&quot; rel=&quot;nofollow noreferrer&quot;&gt;3: to become submerged: SINK&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This would seem to coincide with the usage in a geological context from the &lt;a href=&quot;https://books.google.com/books?id=3y3wAAAAMAAJ&amp;amp;newbks=1&amp;amp;newbks_redir=0&amp;amp;dq=sediment%20deformation%2C%20%20load%20and%20%22founder%22%20structures&amp;amp;pg=RA2-PA28#v=onepage&amp;amp;q&amp;amp;f=true&quot; rel=&quot;nofollow noreferrer&quot;&gt;US Geological Bulletin&lt;/a&gt; article found here:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Figure 29 Outcrop of facies SL massive sandstone in southwestern part&#xA;of Powder River Basin Teapot Dome area Hammer at base is approximately&#xA;28 cm 1 ft long Load casts are developed where fine grained sandstone&#xA;overlies a zone of very fine grained massive silty sandstone Load&#xA;casts are believed to form by unequal loading of water saturated&#xA;hydroplastic sediments that &lt;em&gt;&lt;strong&gt;founder into unstable sediments below&lt;/strong&gt;&lt;/em&gt;&#xA;Overlying the load casts are foresets of planar crossbeds deformed and&#xA;oversteepened by rapid sediment loading from above.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So it appears &lt;em&gt;&lt;strong&gt;founder&lt;/strong&gt;&lt;/em&gt; in this context indicates &lt;em&gt;&lt;strong&gt;sinking&lt;/strong&gt;&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Without seeing your exact context, possibly a layer which shows some intermixing with the layer above due to some sinking sediments during formation.&lt;/p&gt;&#xA;" OwnerUserId="6057" LastActivityDate="2022-02-20T17:54:55.390" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23550" PostTypeId="1" AcceptedAnswerId="23551" CreationDate="2022-02-20T20:36:19.603" Score="3" ViewCount="806" Body="&lt;p&gt;Golly, please help me understand this nitrogen cycle (the terrestrial one). I skimmed through some materials (e.g. &lt;a href=&quot;https://www.nature.com/scitable/knowledge/library/the-nitrogen-cycle-processes-players-and-human-15644632/&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;http://cceonondaga.org/resources/nitrogen-basics-the-nitrogen-cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;) but still don't understand.&lt;/p&gt;&#xA;&lt;p&gt;What I made of all of of it: first it's &amp;quot;fixed&amp;quot; by converting nitrogen from air to &lt;strong&gt;ammonia&lt;/strong&gt; (nitrogen fixation), then it's converted to nitrites and then &lt;strong&gt;nitrates&lt;/strong&gt; (nitrification), then faeces and dead bodies shed their organic nitrogen which is converted into &lt;strong&gt;ammonium&lt;/strong&gt; (ammonification) (I'm only interested in how nitrogen becomes bioavailable so I skip the denitrification phase).&lt;/p&gt;&#xA;&lt;p&gt;The articles say all the three are bioavailable, but Wikipedia &lt;a href=&quot;https://en.wikipedia.org/wiki/Nitrogen_cycle#Ammonification&quot; rel=&quot;nofollow noreferrer&quot;&gt;says&lt;/a&gt; ammonia, at least in its gaseous form, is toxic to plants. So a step of converting ammonia to ammonium was missed, wasn't it? And if ammonia is available enough then what does nitrification have to do with it? I read somewhere (I don't remember where, I closed the tab apparently) that ammonium is good for some plants but generally they, plants, prefer nitrates.&lt;/p&gt;&#xA;&lt;p&gt;Could you give me an article that confirms and, hopefully, explains it? An intelligible explanatory article from an authoritative source would be helpful&lt;/p&gt;&#xA;" OwnerUserId="22632" LastEditorUserId="22632" LastEditDate="2022-03-25T23:23:41.310" LastActivityDate="2022-03-25T23:23:41.310" Title="How does nitrogen cycle work?" Tags="|nitrogen|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23551" PostTypeId="2" ParentId="23550" CreationDate="2022-02-21T06:27:00.727" Score="4" Body="&lt;p&gt;The first step in the nitrogen cycle is atmospheric nitrogen (N&lt;sub&gt;2&lt;/sub&gt;) and water (H&lt;sub&gt;2&lt;/sub&gt;O)&#xA;lightning will make (N&lt;sub&gt;2&lt;/sub&gt;) and (H&lt;sub&gt;2&lt;/sub&gt;O) combine into ammonia (NH&lt;sub&gt;3&lt;/sub&gt;) and nitrate (NO&lt;sub&gt;3&lt;/sub&gt;) this will combine with water and fall to the ground.&lt;/p&gt;&#xA;&lt;p&gt;Step Two is where nitrate can be used by plants directly and the ammonia can be used by bacteria (nitrosomonas)that converts ammonia into nitrite,this nitrite will be converted by an other bacteria (nitrobacter) into nitrate that can be used by plants directly.&lt;/p&gt;&#xA;&lt;p&gt;A part of the nitrate will be converted to free nitrogen (N&lt;sub&gt;2&lt;/sub&gt;) by denitrifying bacteria,this process can only happen in an oxygen free environment (wetlands and similar environments) it can reduce the nitrate content with up to 50% in water.&lt;/p&gt;&#xA;&lt;p&gt;Step three is when plants and the animals that live of the plants die and breaks down into ammonia and other waste products (this is where many explanations of the nitrogen cycle usually starts). The waste products gets converted into ammonia by bacteria and the ammonia gets converted to nitrite and the entire cycle starts all over again.&lt;/p&gt;&#xA;&lt;p&gt;Legumes have a symbiotic relationship with some bacteria that can fixate nitrogen (N&lt;sub&gt;2&lt;/sub&gt;) &lt;a href=&quot;https://aces.nmsu.edu/pubs/_a/A129/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://aces.nmsu.edu/pubs/_a/A129/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;sources:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://science.howstuffworks.com/life/biology-fields/nitrogen-cycle.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://science.howstuffworks.com/life/biology-fields/nitrogen-cycle.htm&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.britannica.com/science/denitrifying-bacteria&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.britannica.com/science/denitrifying-bacteria&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The rest is from my memory.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="2470" LastEditDate="2022-02-21T12:11:38.333" LastActivityDate="2022-02-21T12:11:38.333" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23552" PostTypeId="1" AcceptedAnswerId="23553" CreationDate="2022-02-21T20:35:40.810" Score="3" ViewCount="86" Body="&lt;p&gt;I was walking on a reef in northern Italy near Genoa. (44.3230136N, 9.1462828E) The rock was composed of rocks of varying sizes, colors and shapes held together by some kind of a seemignly softer substrate. The substrate was still rock-hard on touch, but I was able to break some of the smaller rock out of it. (The photos below will say it best.)&lt;/p&gt;&#xA;&lt;p&gt;The reef had several &amp;quot;splits&amp;quot; that ran across its whole length. These were white in colour and, I think, were composed of quartz. Interestingly, these splits ran straight through both the substrate and the rocks as if someone sliced the reef with a laser.&lt;/p&gt;&#xA;&lt;p&gt;I would like to know how these formed. I imagine high pressures and shear forces were at play but I still don't understand how it's possible that the splits don't go around the rocks (at least the smaller ones) but straight through. Especially if I assume the rocks are harder than the substrate. But that might not be the case?&lt;/p&gt;&#xA;&lt;p&gt;See the photo captions for more details.&lt;/p&gt;&#xA;&lt;p&gt;Sorry, for not calling things by their proper names. I'm no geologist so this questions doubles as an identification one. I guess.&lt;/p&gt;&#xA;&lt;p&gt;View of the rock with one of the splits going across vertically roughly in the middle:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/kHY4l.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kHY4l.jpg&quot; alt=&quot;View of the rock with one of the splits going across vertically roughly in the middle.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Wider view of the same split with a person's legs for scale. The split continues behind:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/T26Ql.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/T26Ql.jpg&quot; alt=&quot;Wider view of the same split with a person's legs for scale. The split continues behind.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;One of the small rocks being split in half by a narrow split. My finger on the left for scale:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/SSw0C.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SSw0C.jpg&quot; alt=&quot;One of the small rocks being split in half by a narrow split. My finger on the left for scale.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Overall view of the reef showing a structure of plates laid on each other:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/EPNuK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EPNuK.jpg&quot; alt=&quot;Overall view of the reef showing a structure of plates laid on each other.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26469" LastEditorUserId="26469" LastEditDate="2022-02-22T09:56:17.657" LastActivityDate="2022-02-22T09:56:17.657" Title="How these rock features form?" Tags="|geology|identification-request|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23553" PostTypeId="2" ParentId="23552" CreationDate="2022-02-22T05:34:14.130" Score="3" Body="&lt;p&gt;That's a &lt;a href=&quot;https://en.wikipedia.org/wiki/Conglomerate_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;conglomerate&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The infilled fractures will have formed when it was buried at depth and thus under considerable pressure. The substrate may be physically softer or it may be more chemically reactive and thus erodes more easily at the surface. Regardless at depth there will have been no practical difference in their physical properties so faults will have cut substrate and clasts equally. Faulting is the result of differential movement, usually but not always because of flexion.&lt;/p&gt;&#xA;&lt;p&gt;The filler material will have been deposited by geothermal fluid flowing through the fault. This fluid is hot, high pressure, water saturated with a number of dissolved minerals from the rocks it has been flowing through. When it reaches a fault the pressure, and it's ability to keep those minerals dissolved drops and they precipitate out along the fissure. The nature of the minerals so deposited depends on the depth of burial at time of deposition, at great depth silicates like &lt;a href=&quot;https://en.wikipedia.org/wiki/Quartz&quot; rel=&quot;nofollow noreferrer&quot;&gt;quartz&lt;/a&gt; are dominant, shallower deposits are usually carbonates like &lt;a href=&quot;https://en.wikipedia.org/wiki/Calcite&quot; rel=&quot;nofollow noreferrer&quot;&gt;calcite&lt;/a&gt;, sulfates like &lt;a href=&quot;https://en.wikipedia.org/wiki/Gypsum&quot; rel=&quot;nofollow noreferrer&quot;&gt;gypsum&lt;/a&gt; that have a higher solubility and thus can stay in solution at lower pressures. Given the rocks are probably Mesozoic in age they could well have been buried deeply enough for the deposits to be silica but I'm not really familiar with the deep history of that part of Europe so possibly not. I expect that the larger cracks are older and contain one mineral, probably quartz, while the smaller cracks are younger and have a different infill, probably calcite.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2022-02-22T05:34:14.130" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23554" PostTypeId="1" AcceptedAnswerId="23555" CreationDate="2022-02-22T09:04:41.023" Score="3" ViewCount="488" Body="&lt;p&gt;I always wondered about this, how deep is the water beneath a water fall? I would suspect erosion to erode even rock over time. Are there some visual clues to estimate the water depth? Or is the only safe way to test the depth manually? I always wondered how cliff jumpers or kajakers determine its &amp;quot;safe&amp;quot; to go over said waterfall.&lt;/p&gt;&#xA;" OwnerUserId="11854" LastActivityDate="2022-02-22T09:31:31.773" Title="How deep is the water beneath a waterfall?" Tags="|water|rivers|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23555" PostTypeId="2" ParentId="23554" CreationDate="2022-02-22T09:31:31.773" Score="5" Body="&lt;p&gt;It is completely site dependent, the result of a myriad of factors; the rock type, its structure, the flow of water and how that flow has varied in the past. Flow velocity in the pool below a waterfall might give you some clues as to depth, but the only safe way to know is manual inspection. Even a deep pool might have boulders lurking under the surface.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2022-02-22T09:31:31.773" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23556" PostTypeId="2" ParentId="23544" CreationDate="2022-02-22T10:12:44.397" Score="1" Body="&lt;p&gt;What you see is the location of the warm front. Across the frontal zone, the wind direction changes relatively quickly, but not unexpected, due to warm advection. What may be more unusual is that you see it this clearly close to the surface in a coarse model product (assuming you are looking at GFS or IFS), but that can be because here the warm front moves over water so you don't see too many effects from the surface.&lt;/p&gt;&#xA;" OwnerUserId="17522" LastActivityDate="2022-02-22T10:12:44.397" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23557" PostTypeId="1" CreationDate="2022-02-22T14:13:02.547" Score="5" ViewCount="54" Body="&lt;p&gt;I'm a forest ecologist and college professor who has been teaching about the Earth's &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_circulation&quot; rel=&quot;noreferrer&quot;&gt;convection cell circulation&lt;/a&gt; for many years. Explaining &lt;a href=&quot;https://en.wikipedia.org/wiki/Hadley_cell&quot; rel=&quot;noreferrer&quot;&gt;Hadley cells&lt;/a&gt; is very straightforward with differences in solar radiation and &lt;a href=&quot;https://en.wikipedia.org/wiki/Adiabatic_process#Adiabatic_heating_and_cooling&quot; rel=&quot;noreferrer&quot;&gt;adiabatic thermodynamics&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;However, I have never seen a concise -- and more importantly &lt;em&gt;complete&lt;/em&gt; - explanation for why the higher-latitude convection cells (&lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_circulation#Ferrel_cell&quot; rel=&quot;noreferrer&quot;&gt;Ferrel&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_circulation#Polar_cell&quot; rel=&quot;noreferrer&quot;&gt;Polar&lt;/a&gt;) flow the way they do.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;I would like to offer my hypothesized rationale below, but I would appreciate if anyone can provide a more detailed/complete explanation (or correction!)&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;proper vocabulary and explanation of physical processes a plus!&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;em&gt;My explanation&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Wind travelling downward at 30&lt;sup&gt;o&lt;/sup&gt; latitude from a Hadley cell will deflect in multiple directions (poleward and toward the equator).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cIawdm.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cIawdm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The portion of this air moving poleward along earth's surface will be warmer than any air it's encountering as it moves closer to the pole. As a result of being warmer than the more polar air it runs into, it will begin to rise -- thus, around 60&lt;sup&gt;o&lt;/sup&gt; latitude, the warmer air moves to higher atmospheric levels (&amp;quot;hot air rises&amp;quot;).&lt;/p&gt;&#xA;&lt;p&gt;As that warmer air rises high into the atmosphere at 60 degrees latitude, it's going to cool. Cool air wants to sink. But it can't sink at 60 degrees because all that warm air is pushing up. So instead, as that warm air cools, it's going to spread out both poleward and toward the equator (where it meets less resistance).  Kind of like this image of water is doing (only with air):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/h4rPJm.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/h4rPJm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As that cooler air continues to cool heading toward the equator, it will eventually come back down to earth around 30&lt;sup&gt;o&lt;/sup&gt; -- thus completing the Ferrel cell.&lt;/p&gt;&#xA;&lt;p&gt;However, the air that moves poleward in the atmosphere will continue cooling as it moves poleward --  the cold air sinks at the pole (90 deg). When it sinks it will hit the earth's surface and spread toward the equator. Eventually it warms enough that it will rise again around 60 deg latitude (helped from the warm air it meets from the Ferrel cell). this completes the polar cell.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Again, if you could provide a more detailed (and accurate) explanation, that would be much appreciated!&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="7536" LastActivityDate="2022-02-22T14:13:02.547" Title="How do higher-latitude convection cell currents (Ferrel, Polar) work?" Tags="|climate|thermodynamics|convection|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23559" PostTypeId="1" CreationDate="2022-02-24T03:38:14.930" Score="3" ViewCount="45" Body="&lt;p&gt;I would like to understand why any of the following conditions in a layer of a lacustrine sediment core appear to imply that the lake level was low at the relevant time:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;low C/N ratio&lt;/li&gt;&#xA;&lt;li&gt;low δ&lt;sup&gt;13&lt;/sup&gt;C&lt;/li&gt;&#xA;&lt;li&gt;low concentration of magnetic particles&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;All papers I've come across assume prior knowledge about these relationships, and basic sources like Wikipedia haven't helped me either. My background is mathematics, with little to no chemistry knowledge.&lt;/p&gt;&#xA;" OwnerUserId="26474" LastEditorUserId="26474" LastEditDate="2022-02-24T13:00:42.740" LastActivityDate="2022-02-26T00:38:47.877" Title="Reconstructing lake level from organic and magnetic sediment data" Tags="|geochemistry|sedimentology|paleoclimatology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23562" PostTypeId="2" ParentId="13205" CreationDate="2022-02-25T17:05:27.020" Score="3" Body="&lt;p&gt;Answering my old question:&lt;/p&gt;&#xA;&lt;p&gt;I've found two sources that attempt to answer the GDP change brought about by predicted future climate change.  The short answer is that places north of about Chicago should see an increase in GDP and places south of Chicago should see a decrease in GDP.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.npr.org/sections/thetwo-way/2017/06/29/534896130/mapping-the-potential-economic-effects-of-climate-change&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1v6eX.jpg&quot; alt=&quot;Climate Change and GDP change in the USA&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://web.stanford.edu/%7Emburke/climate/map.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kQhO8.png&quot; alt=&quot;Climate Change and GDP change Worldwide&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.npr.org/sections/thetwo-way/2017/06/29/534896130/mapping-the-potential-economic-effects-of-climate-change&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.npr.org/sections/thetwo-way/2017/06/29/534896130/mapping-the-potential-economic-effects-of-climate-change&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://web.stanford.edu/%7Emburke/climate/map.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://web.stanford.edu/~mburke/climate/map.php&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12085" LastActivityDate="2022-02-25T17:05:27.020" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23563" PostTypeId="2" ParentId="22989" CreationDate="2022-02-25T21:43:01.167" Score="4" Body="&lt;p&gt;Arkaia's answer sounds quite detailed. However depending on what is your required level of precision and goals (climatology ? hydrological forecast at depth ?) there are some valuable extra information for in-depth data.&lt;/p&gt;&#xA;&lt;p&gt;Data previously mentioned are mostly climatologies, smoothing fine scales variability and it should be noticed that 1 degree resolution is extremely coarse for the Mediterranean sea. There are indeed in-situ profiles available on CMEMS, on both delayed-time and near-real-time in the CORA datasets (Coriolis Reanalysis) : &lt;a href=&quot;https://doi.org/10.48670/moi-00039&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.48670/moi-00039&lt;/a&gt; and &lt;a href=&quot;https://doi.org/10.48670/moi-00044&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.48670/moi-00044&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The easiest access is likely by FTP (with tools like Filezilla) :&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;ftp://my.cmems-du.eu/Core/INSITU_GLO_TS_REP_OBSERVATIONS_013_001_b/CORIOLIS-GLOBAL-CORA-OBS&quot; rel=&quot;nofollow noreferrer&quot;&gt;ftp://my.cmems-du.eu/Core/INSITU_GLO_TS_REP_OBSERVATIONS_013_001_b/CORIOLIS-GLOBAL-CORA-OBS&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;ftp://nrt.cmems-du.eu/Core/INSITU_MED_NRT_OBSERVATIONS_013_035/med_multiparameter_nrt&quot; rel=&quot;nofollow noreferrer&quot;&gt;ftp://nrt.cmems-du.eu/Core/INSITU_MED_NRT_OBSERVATIONS_013_035/med_multiparameter_nrt&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;These datasets gather all available data stacked in 1 netcdf file per day and data source, fortunately there is a specific subset for the Med sea.&lt;/p&gt;&#xA;&lt;p&gt;You can distinguish the data sources by the code names : if there is &lt;strong&gt;'PF'&lt;/strong&gt; in the file name, it is an in-situ profile. You are most likely interested in XBT, CTD, Argo floats or glider data (corresponding codes are respectively &lt;strong&gt;'XB','CT','PF','GL'&lt;/strong&gt;)&lt;/p&gt;&#xA;&lt;p&gt;FYI, on the Med sea, filtering out &amp;quot;bad&amp;quot; profiles, you can reach about 125 000 vertical profiles from 2000 to 2022, with of course some areas being a lot under-sampled.&lt;/p&gt;&#xA;&lt;p&gt;That being said, I totally agree the CMEMS catalog is far from being user-friendly&lt;/p&gt;&#xA;" OwnerUserId="26483" LastActivityDate="2022-02-25T21:43:01.167" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23564" PostTypeId="2" ParentId="23559" CreationDate="2022-02-26T00:38:47.877" Score="2" Body="&lt;p&gt;That delta C13 values are useful proxies for lake level because carbon isotope ratios are relevant to organic carbon deposited by lacustrine plants and, critically, for relatively shallow lakes. Past a certain lake depth and those isotope ratios make increasingly less sense.&lt;/p&gt;&#xA;&lt;p&gt;Other chemistries: nitrogen, iron oxidation state are useful indicators of organic growth rates as well as deposition environment, which, incidentally, would tell you if the lake is too deep for using (organically derived) C13 isotopes. One would also want to know if that organic carbon is the result of nitrogen loading, oxygenation, or both, or neither.&lt;/p&gt;&#xA;&lt;p&gt;Check out this paper: &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0031018219300227#:%7E:text=%CE%B413Corg%20effectively%20records,on%20the%20northeastern%20Tibetan%20Plateau.&amp;amp;text=%CE%B413Corg%20is%20more,5%20m%20to%2020%20m.&amp;amp;text=Lakes%20with%20different%20sizes%20have,level%20changes%20on%20the%20TP.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Evaluation of lacustrine organic δ13C as a lake-level indicator: A case study of Lake Qinghai and the satellite lakes on the Tibetan Plateau&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2022-02-26T00:38:47.877" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23565" PostTypeId="1" CreationDate="2022-02-26T01:01:38.357" Score="6" ViewCount="175" Body="&lt;p&gt;I have been working on a simulation to approximate the formation process of dunes. I understand that their formation is a result of saltation and aeolian processes, but I don't understand the exact small scale mechanisms which contribute to their shape.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rXhsI.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rXhsI.png&quot; alt=&quot;Diagram of a dune&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The leeward side of most dunes is steep and straight because the sand slips down it and it exceeds the angle of repose. So what exactly contributes to the gentle curve of the windward side?&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Is more sand removed on steeper parts of the dune?&lt;/li&gt;&#xA;&lt;li&gt;Does the distance of saltation change over the dune?&lt;/li&gt;&#xA;&lt;li&gt;What does the sand flux look like across the surface?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="23082" LastActivityDate="2022-02-27T10:56:44.523" Title="What makes sand dunes shaped asymmetrically?" Tags="|wind|sedimentology|geomorphology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23566" PostTypeId="2" ParentId="23565" CreationDate="2022-02-26T10:17:25.247" Score="6" Body="&lt;p&gt;Saltation cannot proceed up a steeper slope under the wind conditions that prevail in the particular dune's formation. Dunes are basically traffic pile ups for wind driven sand grains, the slip face of a dune is defined almost entirely by the angle of repose of the grains that make up it's structure. The windward side is where new grains join the pile up and the important factor is how far off the ground, on average, the wind is capable of lifting the grains that compose the dune.&lt;/p&gt;&#xA;&lt;p&gt;Saltation is effectively wind assisted grain skipping; on a smooth flat surface the wind could push an individual grain an unlimited distance, with it bouncing off the surface every so often, without it being obstructed in it's forward progress. On flat ground the likelihood of a grain impacting another on the surface that stops it is higher but on a slope an individual grain &lt;em&gt;will&lt;/em&gt; encounter another grain, and quickly, because saltating grains do not rise high above the ground.&lt;/p&gt;&#xA;&lt;p&gt;Dunes usually form around an original obstruction and while they may move across the landscape and even sweep aside would-be barriers when they are larger they are then themselves barriers that perpetuate the blockage of sand grains.&lt;/p&gt;&#xA;&lt;p&gt;To answer the questions at the end of your query:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Is more sand removed on steeper parts of the dune?&lt;br /&gt;&#xA;Yes but no; most of  the individual grains in a dune actually rotate through from windward-to-leeward-to-basement of the dune, not a lot of sand is removed from the dune in any area. There is a much greater rate of vertical motion for grains on the leeward edge of the dune however.&lt;/li&gt;&#xA;&lt;li&gt;Does the distance of saltation change over the dune?&lt;br /&gt;&#xA;Yes saltation distance is a function of wind strength and &amp;quot;average distance to stop&amp;quot; the steeper the slope of the dune is the shorter the distance to stop becomes because saltation is effectively a horizontal flow and the slope of the dune intercepts the very flat ballistic of the grains before they would otherwise hit the ground.&lt;/li&gt;&#xA;&lt;li&gt;What does the sand flux look like across the surface?&lt;br /&gt;&#xA;In terms of grain numbers moving across a given metre grid square pretty even. In terms of movement across the surface area of the dune also very even over time but with movement of the windward slope being slow and steady while movements on the lee slope tend to be more variable and characterised by irregular slips of large areas. In terms of grains joining and leaving the dune that is a matter of how you define a grain as being part of the dune or not but I'd be inclined to go with a model that showed a trickle of new grains on the windward edge with an even smaller number of grains lost at the leeward toe with most of the outgoings being concentrated at the crest.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="10735" LastEditorUserId="239" LastEditDate="2022-02-27T10:56:44.523" LastActivityDate="2022-02-27T10:56:44.523" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="23569" PostTypeId="2" ParentId="22860" CreationDate="2022-02-27T23:02:09.543" Score="1" Body="&lt;p&gt;In fact multiple species of oxygen or nitrogen can create emissions at various wavelengths. There can be aurorae over a wide range of wavelengths, we just see only some of them that happen to be in the visible range. So, it's all a matter of which species hit the relatively narrow visible target.&lt;/p&gt;&#xA;&lt;p&gt;With respect to oxygen, Rezaei et al. &lt;a href=&quot;https://i.stack.imgur.com/3qmbT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt; provide this spectrum, in which atomic oxygen produces an emission near the red end of the visible range, while ions of both monatomic and diatomic oxygen give less intense emissions of various colors from blue to orange. Note that no emission is listed for neutral &lt;span class=&quot;math-container&quot;&gt;$\text{O}_2$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3qmbT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3qmbT.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;With nitrogen, similar results from Hosseini et al. &lt;a href=&quot;https://i.stack.imgur.com/SPos8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt; show an emission in the violet or blue range from ionized diatomic nitrogen, but none from any monatomuc nitrogen species. Note that in this spectrum the red eemission from atomic oxygen is seen, apparently from a small amount of this imputity in the gas sample.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SPos8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SPos8.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;1.&#xA;Rezaei, Fatemeh &amp;amp; Abbasi-Firouzjah, Marzieh &amp;amp; Shokri, Babak (2014). &amp;quot;Investigation of antibacterial and wettability behaviours of plasma-modified PMMA films for application in ophthalmology&amp;quot;, &lt;em&gt;Journal of Physics D Applied Physics&lt;/em&gt;, &lt;strong&gt;47&lt;/strong&gt;, 085401. &lt;a href=&quot;https://doi.org/10.1088/0022-3727/47/8/085401&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1088/0022-3727/47/8/085401&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;2.&#xA;Hosseini, Seyed Iman &amp;amp; Mohsenimehr, Soad &amp;amp; Hadian, Javad &amp;amp; Ghorbanpour, Mansour &amp;amp; Shokri, Babak (2018). &amp;quot;Physico-chemical induced modification of seed germination and early development in artichoke ( Cynara scolymus L.) using low energy plasma technology&amp;quot;, &lt;em&gt;Physics of Plasmas&lt;/em&gt;, &lt;strong&gt;25&lt;/strong&gt;, 013525. &lt;a href=&quot;https://doi.org/10.1063/1.5016037&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1063/1.5016037&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2022-03-07T11:25:25.800" LastActivityDate="2022-03-07T11:25:25.800" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23570" PostTypeId="1" CreationDate="2022-02-28T00:55:32.470" Score="4" ViewCount="168" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Curiosity has actually &lt;a href=&quot;https://mars.nasa.gov/raw_images/206000/?site=msl&quot; rel=&quot;nofollow noreferrer&quot;&gt;seen these types of features before&lt;/a&gt;, which are called diagenetic crystal clusters. Diagenetic means the recombination or rearrangement of minerals, and these features consist of three-dimensional crystal clusters, likely made of a combination of minerals.&lt;/p&gt;&#xA;&lt;p&gt;Curiosity deputy project scientist Abigail Fraeman said on Twitter that these features that were seen previously were made of salts called sulfates.&lt;/p&gt;&#xA;&lt;p&gt;embedded tweet&lt;/p&gt;&#xA;&lt;p&gt;From studies of previous features like this found on Mars (&lt;a href=&quot;https://ntrs.nasa.gov/citations/20150003048&quot; rel=&quot;nofollow noreferrer&quot;&gt;you can read a paper on them here&lt;/a&gt;), originally the feature was embedded within a rock, which eroded away over time. These mineral clusters, however, appear to be resistant to erosion.&lt;/p&gt;&#xA;&lt;p&gt;Another name for these features is concretion, which you may remember from the Opportunity rover, who saw features that were nicknamed '&lt;a href=&quot;https://www.universetoday.com/9666/earth-has-blueberries-too/&quot; rel=&quot;nofollow noreferrer&quot;&gt;blueberries&lt;/a&gt;,' since they were small and round. You can see round concretions next to the flower-like feature in this image.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and later&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Curiosity found another &lt;a href=&quot;https://www.universetoday.com/99457/about-that-flower-on-mars/&quot; rel=&quot;nofollow noreferrer&quot;&gt;flower-like feature&lt;/a&gt; back in 2013, and the Spirit rover found similar-looking rocks that were nicknamed 'cauliflower' features because of their knobby protuberances.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;My impression is that some of these are collections of small crystals that have become chemically &amp;quot;stuck together&amp;quot; in a process which involves liquid water. Some terms might be well defined classes, others may be colloquialisms, but I feel a bit lost with all of these terms.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Blueberries, cauliflower, chert, concretions, accretions and diagenetic crystal clusters on Mars, can you help me sort these all out?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Image below is from the linked article, and the title in the image URL is&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Blackthorn Salt Mineral Formation And Rocks On Mars&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The original can be found at &lt;a href=&quot;https://mars.nasa.gov/raw_images/1029787/?site=msl&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://mars.nasa.gov/raw_images/1029787/?site=msl&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ROV6T.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ROV6T.jpg&quot; alt=&quot;&amp;quot;flower&amp;quot; Blackthorn Salt Mineral Formation And Rocks On Mars&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;(NASA/JPL-Caltech/MSSS/Kevin M. Gill/Flickr/CC BY 2.0)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2022-04-29T00:13:36.420" LastActivityDate="2022-05-21T22:26:32.993" Title="Blueberries, cauliflower, chert, concretions, accretions and diagenetic crystal clusters on Mars, can you help me sort these all out?" Tags="|sedimentology|terminology|mars|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="23571" PostTypeId="1" CreationDate="2022-02-28T02:57:26.493" Score="4" ViewCount="746" Body="&lt;p&gt;CNN's &lt;a href=&quot;https://edition.cnn.com/2022/02/22/world/antarctica-human-pollution-causing-more-snow-melt-climate/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;What is black carbon? The latest way humans are causing changes in Antarctica&lt;/a&gt; doesn't actually say anything about what black carbon is. Neither does The Guardian's &lt;a href=&quot;https://www.theguardian.com/world/2022/feb/22/black-carbon-pollution-from-tourism-and-research-increasing-antarctic-snowmelt-study-says&quot; rel=&quot;nofollow noreferrer&quot;&gt;Black carbon pollution from tourism and research increasing Antarctic snowmelt, study says&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I assume these are &lt;a href=&quot;https://en.wikipedia.org/wiki/Particulates&quot; rel=&quot;nofollow noreferrer&quot;&gt;particulates&lt;/a&gt; due to incomplete burning of hydrocarbon fuels, and those that reach Antarctica must have a fairly small size in order to get there.&lt;/p&gt;&#xA;&lt;p&gt;The ones that absorb light most effectively and melt snow may also have some constrains on composition, though maybe &amp;quot;mostly carbon&amp;quot; is all that can be said.&lt;/p&gt;&#xA;&lt;p&gt;Has there been an attempt to identify the size and composition of black carbon particles that are the primary contributors to snowmelt in Antarctica?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2022-03-01T06:44:26.300" Title="But what exactly is &quot;black carbon&quot; in the context of snow-melting particulates reaching Antarctica?" Tags="|atmosphere|air-pollution|carbon|antarctic|particulates|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="23572" PostTypeId="2" ParentId="23571" CreationDate="2022-02-28T04:16:37.570" Score="4" Body="&lt;p&gt;This issue has been extensively studied and identified.  A Google search regarding the &lt;em&gt;particle size of black carbon&lt;/em&gt; will yield a plethora of information.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Chemically, black carbon (BC) is a component of fine particulate matter (PM ≤ 2.5 µm in aerodynamic diameter).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;See this &lt;a href=&quot;https://www.researchgate.net/publication/327250994_Black_carbon_radiative_effects_highly_sensitive_to_emitted_particle_size_when_resolving_mixing-state_diversity&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt; for a paper by Matsui and co-authors which may answer some aspects regarding your question about identifying the size and composition of black carbon particles, and their radiative effects.&lt;/p&gt;&#xA;&lt;p&gt;Quite obviously, the sources of black carbon are from anything emitting black smoke.  Principal examples are coal-fired power plants, oil field flares and oil refineries, diesel exhaust, and in particular overseas commercial transport shipping, namely, container ships.&lt;/p&gt;&#xA;" OwnerUserId="26494" LastActivityDate="2022-02-28T04:16:37.570" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23573" PostTypeId="1" AcceptedAnswerId="23574" CreationDate="2022-02-28T16:36:12.117" Score="4" ViewCount="91" Body="&lt;p&gt;I'm trying to find the impact of X tonnes of CO&lt;sub&gt;2&lt;/sub&gt; on global temperature so I can infer the unit impact of CO&lt;sub&gt;2&lt;/sub&gt; on temperature. While we know there is a positive correlation, I can't seem to find a study that provides a coefficient.&lt;/p&gt;&#xA;&lt;p&gt;Any guidance would be helpful.&lt;/p&gt;&#xA;" OwnerUserId="26497" LastEditorUserId="2470" LastEditDate="2022-03-01T02:13:19.070" LastActivityDate="2022-03-01T02:13:19.070" Title="What is the unit impact of $\small\sf{CO_2}$ on global temperature?" Tags="|climate-change|climate|temperature|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23574" PostTypeId="2" ParentId="23573" CreationDate="2022-03-01T00:56:05.987" Score="5" Body="&lt;p&gt;As far as I can understand your question, There is not a direct mathematical relationship between CO&lt;sub&gt;2&lt;/sub&gt; and warming, although there is an approximate mathematical relationship between atmospheric CO&lt;sub&gt;2&lt;/sub&gt; concentration and &lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Radiative_forcing&quot; rel=&quot;nofollow noreferrer&quot;&gt;radiative forcing&lt;/a&gt;&lt;/em&gt; which was established in 1998 by &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/98GL01908&quot; rel=&quot;nofollow noreferrer&quot;&gt;this study&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$${\displaystyle \Delta F=5.35\times \ln {C \over C_{0}}~~(\mathrm {W} ~\mathrm {m} ^{-2})\,}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where C is the CO&lt;sub&gt;2&lt;/sub&gt; concentration in question and C&lt;sub&gt;0&lt;/sub&gt; is the baseline CO&lt;sub&gt;2&lt;/sub&gt; concentration (typically 278 ppm is used as this was the CO2 concentration in the atmosphere in 1750 before significant anthropogenic CO&lt;sub&gt;2&lt;/sub&gt; emissions).&lt;/p&gt;&#xA;&lt;p&gt;Unfortunately, this is just an estimate, Earth's climate is extremely complex and the issue is that we still don't fully understand every variable and aspect of the system. The biggest of the uncertainties relates to &lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_sensitivity&quot; rel=&quot;nofollow noreferrer&quot;&gt;climate sensitivity&lt;/a&gt; - this refers to the various earth processes that create feedback loops, which can both amplify and reduce changes in temperature. Without complete knowledge of all variables that influence the Earth's climate (and there are many) and how they all interact with each other, we cannot determine the precise mathematical relationship between CO&lt;sub&gt;2&lt;/sub&gt; and warming, we can only make estimations.&lt;/p&gt;&#xA;" OwnerUserId="26499" LastEditorUserId="2470" LastEditDate="2022-03-01T02:12:39.297" LastActivityDate="2022-03-01T02:12:39.297" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23575" PostTypeId="2" ParentId="23571" CreationDate="2022-03-01T06:44:26.300" Score="2" Body="&lt;p&gt;Black carbon, aka &amp;quot;soot&amp;quot;, is, in the context of Antarctica, the product of the ocean transport industry that brings tourists and supplies to Antarctica.&lt;/p&gt;&#xA;&lt;p&gt;Ocean transport is poorly regulated and commonly allows the burning of both low grade fuels and &amp;quot;bunk&amp;quot; oil at open sea (which is a notoriously filthy emitter of soot). Although cruise ships are unlikely to burn bunk oil, it is possible that resupply ships burn bunk oil in travelling to Antarctica.&lt;/p&gt;&#xA;&lt;p&gt;Soot particles don't travel particularly long distances, eliminating other sources such as forest tires, truck transport, and industry, in the case of Antarctica. However, as soot travels, the particles may coalesce into much larger particles that both warm the surrounding air with absorbed solar radiation, and warm surrounding snow and ice when settled out of the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;Because soot is insoluble, it remains on a surface until it is washed away. This is made difficult because soot melts through transparent ice where it continues to absorb solar radiation, causing melting, but out of reach of surface rinsing. Over time the warming effects of deposited soot multiply as soot layers become more concentrated by this preferential melting process.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2022-03-01T06:44:26.300" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23576" PostTypeId="2" ParentId="22748" CreationDate="2022-03-01T13:55:51.753" Score="2" Body="&lt;p&gt;The geostrophic equilibrium is indeed without any time evolution, and even the quasi-geostrophic version only introduces a weak time dependence in the momentum equation (but in &lt;span class=&quot;math-container&quot;&gt;$O(Rossby)$&lt;/span&gt;). Geostrophic equilibrium is then purely diagnostic, but not prognostic. Density gradient can only be neutralized by adding some dissipation (either through mixing or friction).&lt;/p&gt;&#xA;&lt;p&gt;As a quite rough first guess, adding a dissipation coefficient &lt;span class=&quot;math-container&quot;&gt;$K$&lt;/span&gt; and having geostrophic density gradient scaling with the Rossby deformation radius &lt;span class=&quot;math-container&quot;&gt;$R_d$&lt;/span&gt;, I would dimensionnally answer that the typical timescale would be &lt;span class=&quot;math-container&quot;&gt;$ \tau \sim R_d^2/K$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;However numerical application with ocean value of horizontal mixing &lt;span class=&quot;math-container&quot;&gt;$K \approx 1 \,m^2/s$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$R_d \approx 50 \,km$&lt;/span&gt; leads to decay in decades (lol).&lt;/p&gt;&#xA;&lt;p&gt;Some mesoscale eddies can last for as much as 4-5 years, but it probably means that in the real ocean other forcings (atmospheric in particular) can destroy geostrophic structure over shorter timescales.&lt;/p&gt;&#xA;" OwnerUserId="26483" LastActivityDate="2022-03-01T13:55:51.753" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23577" PostTypeId="2" ParentId="14214" CreationDate="2022-03-02T21:16:17.087" Score="3" Body="&lt;p&gt;The simple answer is: of course.&lt;/p&gt;&#xA;&lt;p&gt;Sand is defined as a lose granular material with grains between 0.074 and 4.75 mm diameter (US definition) or 0.0625 to 0.2 mm (Wentworth, 1922, scale). There is also a logarithmic scale referred to as the Phi scale (Krumbein 1934). Basically grain sizes between approx. 0.05 to 2 mm are defined as sand. Anywhere where there is exposed sediment, some of the sediment will be in the sand fraction.&lt;/p&gt;&#xA;&lt;p&gt;To obtain &amp;quot;pure&amp;quot; sand it is necessary that some sorting agent act on the sediment. This can be achieved by wind, flowing water (rivers) and wave action. These processes will to different degrees sort out certain grain sizes and provide accumulations of limited grain size distribution. All of the transport processes tend to sort material to some extent. Wind is most limiting, whereas flowing water and wave action is less so but in all cases the sorting depends on the energy provided to move the sediment.&lt;/p&gt;&#xA;&lt;p&gt;Since Antarctica is largely covered by ice there are not large areas exposed to wave action, flowing river water or wind. But along the shore of the Antarctic peninsula there are many sediment beaches exposed to wind and wave action. In addition, the Dry Valleys area is a low precipitation area that has experienced dry desert conditions for maybe 2 Ma (Fountain et al 1999). In such areas there is ample opportunity for sorting processes to generate well sorted sediments and hence sands. Whether sands will accumulate in the form of dunes or be deposited in other landforms depend on the processes in the area and where sediments accumulate. Many beaches on the Antarctic peninsula are for example dominated by boulders because the smaller fractions are eroded away to more protected bays. This is common in all environments.&lt;/p&gt;&#xA;&lt;p&gt;So sands are present in Antarctica for the same reasons as sands appear elsewhere on the Earth. Limitations come from the area exposed to sorting processes in Antarctica since much sediment is covered by glacier ice. We also need to remember that glacier ice is to a large extent responsible for creating smaller fractions of sediment due to crushing processes (Hooke and Iverson, 1998)&lt;/p&gt;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&lt;p&gt;Fountain AG, Lyons WB, Burkins MB, Dana GL, Doran PT, Lewis KJ, McKnight DM, Moorhead DL, Parsons AN, Priscu JC, Wall DH, Wharton RA, Virginia RA, 1999. Physical Controls on the Taylor Valley Ecosystem, Antarctica. BioScience. 49 (12), 961–971. doi:&lt;a href=&quot;https://doi.org/10.1525/bisi.1999.49.12.961&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.2307/1313730&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Hooke, RLeB, Iverson, NR, 1995. Grain-size distribution in deforming subglacial tills: Role of grain fracture. Geology 23 (1), 57–60.&#xA;doi:&lt;a href=&quot;https://doi.org/10.1130/0091-7613(1995)023%3C0057:GSDIDS%3E2.3.CO;2&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.1130/0091-7613(1995)023&amp;lt;0057:GSDIDS&amp;gt;2.3.CO;2&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Krumbein WC, 1934. Size frequency distributions of sediments. Journal of Sedimentary Petrology. 2 (4), doi:&lt;a href=&quot;https://doi.org/10.1306/D4268EB9-2B26-11D7-8648000102C1865D&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.1306/D4268EB9-2B26-11D7-8648000102C1865D&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Wentworth CK, 1922 A Scale of Grade and Class Terms for Clastic Sediments. The Journal of Geology, 30 (5), 377-392. doi:&lt;a href=&quot;https://doi.org/10.1086/622910&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.1086/622910&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="725" LastEditDate="2022-03-04T22:29:42.263" LastActivityDate="2022-03-04T22:29:42.263" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23578" PostTypeId="1" CreationDate="2022-03-02T22:00:28.960" Score="6" ViewCount="75" Body="&lt;p&gt;High alpine pyramidal peaks formed by cirque-carving glaciers very commonly (not always) have three nearly symmetrical faces and corresponding ridges spaced roughly 120 deg. apart. This is easily visible in a random search of alpine topo maps, Google Earth etc. Without conducting an exhaustive statistical study, it in fact seems to be the most common alpine shape.&lt;/p&gt;&#xA;&lt;p&gt;Is there some principle of physics or geology that causes the erosion of the cirques to form in this regular pattern?&lt;/p&gt;&#xA;" OwnerUserId="11172" LastActivityDate="2022-03-05T00:46:28.507" Title="Why are symmetrical three-sided pyramidal peaks so common?" Tags="|erosion|glaciation|mountain-building|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23579" PostTypeId="1" CreationDate="2022-03-02T22:55:51.170" Score="3" ViewCount="20" Body="&lt;p&gt;I'm sorry if I'm asking in the wrong forum. I'm a computational scientist and I do not have much physics background.&lt;/p&gt;&#xA;&lt;p&gt;I'm working on constructing machine learning models from data. Currently, I've only been working on toy problems using data generated from numerical simulations of physical processes. One example that has worked well for me is &lt;a href=&quot;https://pyqg.readthedocs.io/en/latest/examples/sqg.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this surface quasi-geostrophic model&lt;/a&gt;. The numerical simulation provides the buoyancy on a grid for various time steps. I'm training a machine learning model on this data to predict the buoyancy over a grid at a particular time for a different initial condition.&lt;/p&gt;&#xA;&lt;p&gt;I'm now thinking whether this can be applied to a real data set. I've read that the surface quasi-geostrophic model is used to model cyclones. My question is: are there available data sets of the buoyancy of a cyclone over a spatial grid? I'd appreciate some references if there are any. Thanks!&lt;/p&gt;&#xA;" OwnerUserId="26503" LastActivityDate="2022-03-02T22:55:51.170" Title="radar data for buoyancy measurements of cyclones" Tags="|atmosphere|climate|climate-models|tropical-cyclone|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23580" PostTypeId="1" CreationDate="2022-03-03T00:14:15.047" Score="2" ViewCount="274" Body="&lt;p&gt;The Moon's orbital plane is inclined by about 5.1° with respect to the ecliptic plane, whereas the Moon's equatorial plane is tilted by only 1.5°.&lt;/p&gt;&#xA;" OwnerUserId="24936" LastActivityDate="2022-03-04T17:55:49.923" Title="What is the elevation angle of sun at lunar poles?" Tags="|planetary-science|remote-sensing|solar-terrestrial-physics|moon|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23581" PostTypeId="1" CreationDate="2022-03-03T18:17:52.593" Score="2" ViewCount="53" Body="&lt;p&gt;I have a table that looks like the image below:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0rEln.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0rEln.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It has a lot of missing Aerosol Optical Depth (AOD) data. To solve the only the spatial component of the problem, one can use a multivariate interpolation like inverse distance weighting, popularly known as IDW. However, will the IDW multivariate interpolation work for the temporal component too? And if not, could someone advise me on what to do in such a scenario.&lt;/p&gt;&#xA;" OwnerUserId="12660" LastEditorUserId="12660" LastEditDate="2022-03-04T07:55:22.070" LastActivityDate="2022-03-04T07:55:22.070" Title="What is the best method for the spatiotemporal interpolation of Aerosol Optical Depth (AOD)?" Tags="|statistics|interpolation|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23582" PostTypeId="2" ParentId="23580" CreationDate="2022-03-04T10:22:54.087" Score="2" Body="&lt;p&gt;The picture shown below holds the key to the answer. The maximum elevation angle the Sun can make is the sum of the Moon's own equatorial tilt (1.5°) and the angle formed by the ecliptic plane and the Moon as viewed &lt;strong&gt;from the Sun.&lt;/strong&gt; As shown in the diagram, the Moon makes a 5.1° angle with the ecliptic when viewed &lt;strong&gt;from the Earth&lt;/strong&gt;, for the Moon is directly orbiting the Earth. Because the Sun is so much farther away, the ecliptic angle viewed from the Sun is correspondingly smaller, only about 0.01°, and so the Sun's maximum elevation angle at the lunar poles is essentially the 1.5° tilt angle (the 0.01° figure is not a significant digits given the rounded values of the angles).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CPQCH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CPQCH.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This low angle has some physical significance. Because many of the crater walls on the Moon slope with much larger angles than that 1.5°, the craters near the poles contain shadows within where the Sun is too low for its light (and heat) to get past the rim. Where these shadows reach the bottom, the bottom is permanently dark and cold, and scientists believe that water ice may be embedded in such shadowed places (crater bottoms near the poles). The planet Mercury presents a similar situation and despite its being close to the Sun, it could harbor water ice in crater bottoms near the poles too.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2022-03-04T17:55:49.923" LastActivityDate="2022-03-04T17:55:49.923" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23583" PostTypeId="1" CreationDate="2022-03-04T19:21:44.267" Score="3" ViewCount="64" Body="&lt;p&gt;So, I am mixing up a substrate from peat and perlite,50%/50%, and I am adding some dolomite lime and gypsum as additives, as vermaculite is too expensive to substitute for the perlite.&lt;/p&gt;&#xA;&lt;p&gt;As I am unable to find granular gypsum, my question is if I can use something that is sold in hardware stores around here as a substitute - it is very cheap and is called &amp;quot;construction gypsum&amp;quot;. It is sold in 10 kilo bags and after mixing with water hardens for a minute or two.&lt;/p&gt;&#xA;&lt;p&gt;I would also like to know what is the best way to add silica to the substrate, as I have found an additive that is called rhino-something, but it is only for flowering, as it contains potassium, as I understand.&lt;/p&gt;&#xA;" OwnerUserId="26509" LastActivityDate="2022-04-03T22:05:40.500" Title="Can I use building gypsum as a soil additive?" Tags="|soil|" AnswerCount="1" CommentCount="0" ClosedDate="2022-04-14T02:03:29.837" ContentLicense="CC BY-SA 4.0" />
  <row Id="23584" PostTypeId="2" ParentId="23583" CreationDate="2022-03-04T20:42:16.100" Score="2" Body="&lt;p&gt;Apparently building gypsum is also known as Plaster of Paris. I put a few tons of gypsum drywall on a 1200 sq.ft. garden.  It is free in some locations ( I got &amp;quot;bearings&amp;quot; - 6&amp;quot; X 48&amp;quot; strips- in a small railyard). I wanted to acidify my clay soil. Over winter the paper on each side, got wet and came off so I had to pick up and discard paper . In spring , I rototilled with a serious ( Howard Gem, 18 Hp Wisconsin) borrowed rototiller. So it was messy , some work, but free. An alternative is plaster of Paris power in a bag as you describe, very neat but costly in quantity. So you can add gypsum but what isthe objective, to add sulfur ? I was trying to change pH, that was relatively ineffective with gypsum.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastEditorUserId="8409" LastEditDate="2022-03-04T21:47:45.573" LastActivityDate="2022-03-04T21:47:45.573" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23585" PostTypeId="2" ParentId="23578" CreationDate="2022-03-05T00:46:28.507" Score="-1" Body="&lt;p&gt;It's an expression of what my lecturers used to call the rule of six, they seemed to consider it something of a natural constant. The peaks look triangular from a distance but they're actually hexagonal with three long sides and three very short sides at the apparent vertices. Why 6 sided forms are so common in nature, is a matter that has been debated for time immemorial without, to my knowledge, any answer that can be broadly applied but the phenomenon demonstrably exists; columnar jointing whether caused by cooling or physio-chemical bonding forms six sided prisms, minerals with two and three fold symmetry form six sided crystals, the cirques are effectively V shaped erosion features three of them gives you another 6 sided formation at the base of the peak as well.&lt;/p&gt;&#xA;" OwnerUserId="10735" LastActivityDate="2022-03-05T00:46:28.507" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23586" PostTypeId="1" CreationDate="2022-03-05T07:08:41.457" Score="3" ViewCount="141" Body="&lt;p&gt;I had noticed this on Google Earth and Celestia already.&lt;/p&gt;&#xA;&lt;p&gt;Here's an image from the ISS: &lt;a href=&quot;https://i.stack.imgur.com/NXrQw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NXrQw.jpg&quot; alt=&quot;Terrestrial Terminator Line&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As you can see on the horizon, at the terminator the atmosphere doesn't seem to follow the curvature any longer but instead moves away from the Earth's horizon. Is it just an optical effect or are certain atmospheric layers actually higher at the night side? What's causing this?&lt;/p&gt;&#xA;" OwnerUserId="26511" LastActivityDate="2022-03-12T20:36:32.253" Title="Why does the Earth's atmosphere appear to no longer follow the curvature beyond the terminator line?" Tags="|atmosphere|atmosphere-modelling|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23587" PostTypeId="2" ParentId="19116" CreationDate="2022-03-05T15:04:55.053" Score="6" Body="&lt;p&gt;Water above the blue line flows to the arctic.  No question there.  Water below the green line flows to the Atlantic.  Also no debate.&lt;/p&gt;&#xA;&lt;p&gt;Water between the blue and green lines flows to Hudson Bay.  But where does Hudson Bay flow?  The answer, technically, is both.  But which one does it &lt;em&gt;primarily&lt;/em&gt; flow to?  From &lt;a href=&quot;https://www.whoi.edu/fileserver.do?id=89084&amp;amp;pt=2&amp;amp;p=31111#:%7E:text=The%20Hudson%20Bay%20System%2C%20which,inflow%20of%20Arctic%20Ocean%20waters.&quot; rel=&quot;noreferrer&quot;&gt;this article&lt;/a&gt;, it seems like the vast majority of flow &lt;em&gt;out of Hudson Bay&lt;/em&gt; is to the Atlantic.  In fact, it's an enormous source of freshwater &lt;em&gt;to&lt;/em&gt; the Atlantic.  A lot of that water comes &lt;em&gt;from&lt;/em&gt; the Arctic Ocean (and here is where the definition of 'ocean' becomes itself kind of fraught).&lt;/p&gt;&#xA;&lt;p&gt;But if you were to simply ask: &amp;quot;at which point in the continental US would water &lt;em&gt;FLOW&lt;/em&gt; to three different oceans?&amp;quot;, Snow Dome has the better claim.  The majority of water leaving the Montana Peak towards Hudson Bay will end up in the Atlantic Ocean, not the Arctic.&lt;/p&gt;&#xA;&lt;p&gt;If you were to ask, &amp;quot;at which point(s) does &lt;em&gt;any&lt;/em&gt; water flow to all three Oceans?&amp;quot;, it's technically the entire locus of points along the great divide between these two &amp;quot;triple points&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;But if you had to pick just one point, Snow Dome seems more appropriate.&lt;/p&gt;&#xA;" OwnerUserId="26513" LastActivityDate="2022-03-05T15:04:55.053" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23590" PostTypeId="1" CreationDate="2022-03-05T21:29:25.887" Score="1" ViewCount="87" Body="&lt;p&gt;I am given examples of this for Brampton (Canada) (43° 41’ latitude)&lt;/p&gt;&#xA;&lt;p&gt;On the Summer Solstice you do latitude minus the Earth’s axis tilt which is 23° 26’, so 43° 41’ - 23° 26’ = 20° 15’.&lt;/p&gt;&#xA;&lt;p&gt;On the Winter Solstice you do latitude plus the Earth's axial tilt, so 43.° 41’ + 23° 26’ = 67° 07’.&lt;/p&gt;&#xA;&lt;p&gt;I found that the latitude of Kinshasa is approximately 4° 19'S but I'm not sure how we would use this information to solve the question. If we would subtract from the Earth axis tilt we would get a negative value, which doesn't make sense to me. From what I know is that the Summer Solstice occurs when the sun is directly over the Tropic of Cancer, which is located at 23.5° latitude. The Winter Solstice occurs when the sun is directly over the Tropic of Capricorn, which is located at 23.5° south of the equator. Kinshasa is located in the tropic of Capricorn. So can you help me understand how to calculate these?&lt;/p&gt;&#xA;" OwnerUserId="26514" LastEditorUserId="18081" LastEditDate="2022-03-07T09:24:03.027" LastActivityDate="2022-03-08T05:27:22.393" Title="How far Kinshasa DRC is tilted away from the solar plane on the summer and winter solstices?" Tags="|climate|seasons|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23591" PostTypeId="1" AcceptedAnswerId="23594" CreationDate="2022-03-05T21:40:48.883" Score="1" ViewCount="704" Body="&lt;p&gt;The map presents a summary example of topography and mapped units X and Y. From the information presented, can someone help me determine or estimate the actual dip along the line of section, A-A'? &lt;a href=&quot;https://i.stack.imgur.com/uoOtV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uoOtV.jpg&quot; alt=&quot;cross section &quot; /&gt;&lt;/a&gt;  I am somewhat uncertain regarding the steps to be taken given the information presented on this example map.  What, specifically, is the difference between true dip and apparent dip in regard to A-A'?&lt;/p&gt;&#xA;" OwnerUserId="26517" LastEditorUserId="-1" LastEditDate="2022-03-08T01:54:18.883" LastActivityDate="2022-03-12T15:24:13.037" Title="In Geology - True Dip versus Apparent Dip: When dip is estimated along a line of section, how is that dip determined in relation to true dip?" Tags="|geology|mapping|structural-geology|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23592" PostTypeId="2" ParentId="9589" CreationDate="2022-03-06T06:42:20.607" Score="1" Body="&lt;p&gt;In Arizona, I find this coating on agates/chalcedony. But, I think it forms in a reaction caused by the sun, as it will be on the top of the rocks and not on the underside in contact with the soil.&lt;/p&gt;&#xA;" OwnerUserId="26519" LastActivityDate="2022-03-06T06:42:20.607" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23593" PostTypeId="1" CreationDate="2022-03-06T14:17:07.973" Score="4" ViewCount="211" Body="&lt;p&gt;&lt;strong&gt;Since the mouth of this water body is actually very wide, why do we call it a Gulf?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;What exactly is the difference between a Gulf and a Bay?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rLZmw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rLZmw.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26426" LastActivityDate="2022-03-06T14:17:07.973" Title="Why is the Gulf of Alaska not a Bay? What is the difference between a Gulf and a Bay?" Tags="|oceanography|water|land-surface|land|" AnswerCount="0" CommentCount="6" ClosedDate="2022-03-07T20:21:19.863" ContentLicense="CC BY-SA 4.0" />
  <row Id="23594" PostTypeId="2" ParentId="23591" CreationDate="2022-03-07T05:18:58.633" Score="6" Body="&lt;p&gt;This is an excellent question.  The answer requires that one visualize a 3-dimensional space with a dip plane, a vertical plane coincident with, and aligned along, our line of interest, and the trace that our line of interest will make on the dip plane where the vertical plane and dip plane intersect.  These aspects are already projected onto a two-dimensional map.  In this answer, true dip is taken as the dip measured or estimated &lt;em&gt;perpendicular&lt;/em&gt; to the strike.  &lt;em&gt;Dip is always given a compass heading in the down direction of the dip.&lt;/em&gt;  Apparent dip is any other dip measured or estimated, and similarly given a compass heading.  Also note that &lt;em&gt;rise&lt;/em&gt; and &lt;em&gt;fall&lt;/em&gt; are somewhat synonymous terms regarding elevation change over a measured horizontal distance.&lt;/p&gt;&#xA;&lt;p&gt;We can readily identify, on the provided &lt;em&gt;geologic&lt;/em&gt; map, two marked geologic units, X and Y, topographic elevation contours at 400 ft and 300 ft, geologic-unit contacts or boundaries denoting the top of unit X, contact of unit X with unit Y (which is also the bottom of unit X, or the top of unit Y), and bottom of unit Y.  Presumed units W above, and Z below, are unmarked.  North is indicated, and a graduated 1000 ft scale is given, marked in 250 ft divisions. &lt;em&gt;Also, the trace of a line of section, A - A', is shown on the map.&lt;/em&gt; This is our line of interest. Within the given context of the question, the dip of line A - A' that is desired is of the projection of line A - A' onto a formation contact; or &lt;em&gt;equivalently&lt;/em&gt; for a vertical section along A - A', the apparent dip of the formations in that vertical projection. Otherwise, the true dip of line A - A' in the map plane is &lt;em&gt;zero.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;To make this exercise easier to do we need the following -&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;drafting straight edge&lt;/li&gt;&#xA;&lt;li&gt;protractor&lt;/li&gt;&#xA;&lt;li&gt;engineer's scale (to proportion our map scale for measured distance)&lt;/li&gt;&#xA;&lt;li&gt;drafting pencil (2 or 2H)&lt;/li&gt;&#xA;&lt;li&gt;vinyl eraser for goofs/corrections&lt;/li&gt;&#xA;&lt;li&gt;a drafting brush helps keep the drafting surface clean&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The explanation, herein, will use and explain measurements by hand so that the process will be clear.  A piece of drafting vellum or tracing paper placed over our map is sometimes easier for sketching work and correcting errors or noting scratch calculations.&lt;/p&gt;&#xA;&lt;p&gt;First, &lt;em&gt;we have to determine the true dip and strike of these units&lt;/em&gt; by structure-contouring one of the contact surfaces.  An obvious choice is to use the contact boundary between units X and Y.  Notice that this contact crosses the 300 ft topographic elevation contour in 3 locations on our map. Consequently, the elevation of the contact is 300 ft at these locations.  We can free-hand sketch a &lt;em&gt;structure contour&lt;/em&gt; through these three points, but they are close enough to being along a straight line that we can use a straight edge to sketch-in a 300 ft contour line for the structure contour through these points.  The alignment of this contour is along the &lt;em&gt;strike&lt;/em&gt; of the contact between units X and Y.  Take note of the compass alignment of this contour, &lt;em&gt;and take note of the compass alignment of our line of interest, A - A'.&lt;/em&gt;  Of particular interest is the noted angle between the compass headings of these lines.&lt;/p&gt;&#xA;&lt;p&gt;The following were determined from the map: 1) alignment of A - A' is N 60 deg E (or S 60 deg W), and 2) alignment of 300 ft structure contour, N 75 deg E (or S 75 deg W).  The angle between these lines is difference between their headings, or 15 deg.  The true dip of the X - Y contact is to the northwest. In other words, &lt;em&gt;the true dip heading of the X - Y contact is perpendicular to the northeast - southwest alignment of the strike.&lt;/em&gt;  The alignment of the strike is N 75 deg E (or S 75 deg W).&lt;/p&gt;&#xA;&lt;p&gt;To continue, we note that the contact of interest crosses the 400 ft topographic elevation contour at 4 locations, all essentially in a linear alignment parallel to the 300 ft structure contour, and somewhat to the southeast.  We, therefore, use our straight edge to again sketch-in the parallel alignment of the 400 ft-elevation structure contour. The dip of this contact surface is determined by the arctan(rise/run), wherein the rise is the difference in elevation between the contours, or 100 ft, and the run is determined from the map distance measured perpendicularly between 400 and 300 ft contours, or about 400 ft. Doing the math, the dip is determined as approximately 14 deg. Note the true dip is to the &lt;em&gt;northwest,&lt;/em&gt; or 14 deg true dip directed, or aligned at, N 15 deg W.  In other words, the map direction of the true dip is perpendicular to the strike, and by using the rise/run we have determined the true dip angle is approximately 14 deg.&lt;/p&gt;&#xA;&lt;p&gt;Second, we take note of some simple 3-dimensional aspects related to the dip and strike of our X - Y contact, and the map direction of our line of interest.  We are interested in knowing the apparent dip traced by of our line of interest on the X - Y contact surface.  The line of strike is a horizontal line that has no dip, and we know the rise and run used to determine the contact dip. Essentially, any line of strike (such as a &lt;em&gt;tangent&lt;/em&gt; to a structure contour) defines a level line. But the path of our line of interest is tilted against the contact surface. &lt;em&gt;The dip of line A - A' projected on the contact surface, is presented by the intersection of a vertical plane containing A - A', at the contact surface.&lt;/em&gt;  The slope of the line of interest along the contact plane is an apparent dip, the value of which we seek.&lt;/p&gt;&#xA;&lt;p&gt;Let's examine some details. When looking at our map, we are looking perpendicular to a horizontal-plane projection of mapped features.  Our line of section, A - A', is in a vertical plane that is perpendicular to our map plane. We have to visualize how this line of section is projected onto the contact surface.  Obviously, the line of section on the contact surface is defined by the intersection of the vertical plane with the contact surface.&lt;/p&gt;&#xA;&lt;p&gt;Imagine we are facing down-dip while standing on our line of interest where it crosses the 300 ft elevation structure contour of our contact surface. This would be just to the east of where our line of interest crosses the 300 ft topographic elevation contour; we are standing on our line of interest in the very basal section of formation X.  To the left, our line of interest can be imaginarily seen tracing a path that is rising gently along the surface of the X - Y contact; to the right descending gently along the contact surface. We already have mapped information on the dip and strike that is useful: the map distance between the 300 and 400 ft structure contours of the contact surface is a run of 400 ft, consequently resulting in an elevation change (rise) of 100 ft. The apparent dip of our line of interest can be determined trigonometrically from the application of this information, and the angle made by the heading of the line of interest with the X - Y contact line of strike.  Let's see how.&lt;/p&gt;&#xA;&lt;p&gt;The line of &lt;em&gt;true dip&lt;/em&gt; on our X - Y contact &lt;em&gt;is aligned down-elevation&lt;/em&gt; on the X - Y contact plane &lt;em&gt;perpendicular to the strike.&lt;/em&gt; From where we stand, we can scribe an imaginary circular arc of radius 400 ft &lt;em&gt;on the map plane&lt;/em&gt; that crosses our line of interest and the line of strike defined by the 300 ft elevation structure contour of our contact surface. The radius of the circular arc is the distance of the run used in determining the dip. The angle measured between the line of interest and the line of strike of the X - Y contact surface is 15 deg.  This was determined as the difference, in degrees, of their heading alignments.  The apparent &lt;em&gt;vertical rise (or fall)&lt;/em&gt; of our line of interest &lt;em&gt;along the plane of the X - Y contact&lt;/em&gt; will be the sine of the measured angle between the map heading of the line of interest and strike heading of the X - Y contact (sin of 15 deg) &lt;em&gt;times&lt;/em&gt; the known vertical rise (100 ft) of the contact true dip. This gives a vertical rise (or fall) of about 26 ft.  Taken along a run of 400 ft, the vertical angle is the arctan(26/400), or about 3.7 deg.  Along our line of interest, therefore, the magnitude and direction of this &lt;em&gt;apparent dip&lt;/em&gt; is 3.7 deg aligned at N 60 deg E. Our map units, therefore, projected onto the vertical plane of the A - A' line of section, would show an apparent dip of about 3.7 deg.&lt;/p&gt;&#xA;" OwnerUserId="26522" LastEditorUserId="-1" LastEditDate="2022-03-08T14:09:54.953" LastActivityDate="2022-03-08T14:09:54.953" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23595" PostTypeId="2" ParentId="23590" CreationDate="2022-03-08T05:27:22.393" Score="2" Body="&lt;p&gt;A simple diagram may help to explain the calculations. 23° 26' is the north and south latitudes where the Sun is overhead on the solstices. The angles that you give for Brampton Canada are the zenith distance of the Sun; that is, the angle between the point overhead (the zenith) and the Sun at noon.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Vqi1Q.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Vqi1Q.png&quot; alt=&quot;sun's position&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;For summer at Brampton, A = 43° 41' - 23° 26' = 20° 15'.&lt;/li&gt;&#xA;&lt;li&gt;For winter at Brampton, B = 43° 41' + 23° 26' = 67° 07'. (The Sun is further from the zenith and lower in the sky in winter.)&lt;/li&gt;&#xA;&lt;li&gt;For summer at Kinshasa, D = 23° 26' - 4° 19' = 19° 07'.&lt;/li&gt;&#xA;&lt;li&gt;For winter at Kinshasa, C = 23° 26' + 4° 19' = 27° 45'. (The Sun is further from the zenith and lower in the sky in winter.)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="19137" LastActivityDate="2022-03-08T05:27:22.393" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23596" PostTypeId="1" CreationDate="2022-03-08T17:10:06.217" Score="2" ViewCount="54" Body="&lt;p&gt;The temperature increase with altitude in the stratosphere is caused by the UV radiation absorbed in the ozone layer, isn't it? What if there was no ozone layer? Would temperature keep decreasing beyond the tropopause (which wouldn't exist then) until the mesopause at 53 mi (85 km) above sea level? If so, would the mesopause be even colder than now or what would the temperature profile look like?&lt;/p&gt;&#xA;" OwnerUserId="26511" LastActivityDate="2022-03-08T17:10:06.217" Title="If there was no ozone layer, would the temperature decrease all the way from sea level to the mesopause?" Tags="|atmosphere|temperature|ozone|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23597" PostTypeId="1" CreationDate="2022-03-10T12:23:01.697" Score="-3" ViewCount="205" Body="&lt;p&gt;The theory says that the energy absorbed by carbon dioxide is returned to the Earth's surface and raises its temperature.&lt;br /&gt;&#xA;But, the surface has mass, earth, soil, rocks, etc., and this needs energy if the temperature is to increase.&lt;br /&gt;&#xA;Remember,   Energy = mass * specific heat * increase in temperature&lt;/p&gt;&#xA;&lt;p&gt;Why is this point never mentioned in the theory?  It seems to have been completely ignored.&lt;br /&gt;&#xA;Eddie Banner&lt;/p&gt;&#xA;" OwnerUserId="26536" LastActivityDate="2022-03-14T16:06:55.107" Title="Why does the mainstream greenhouse gas theory for global warming ignore the mass of the surface?" Tags="|temperature|greenhouse-gases|" AnswerCount="1" CommentCount="8" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23598" PostTypeId="1" AcceptedAnswerId="23600" CreationDate="2022-03-10T13:33:39.947" Score="1" ViewCount="171" Body="&lt;p&gt;The Badlands Guardian is a geomorphological feature; see &lt;a href=&quot;https://www.thearchaeologist.org/blog/the-badlands-guardian-a-geomorphic-feature-or-an-ancient-geoglyph&quot; rel=&quot;nofollow noreferrer&quot;&gt;this website&lt;/a&gt;. According to Wikipedia, this figure has been created by natural processes. However, my intuition says that the chance that this happens is small.&lt;/p&gt;&#xA;&lt;p&gt;Could one make a model of the geological processes in this area, and also make an estimate when an image looks 'good enough' like a human? Then it might be possible to calculate the chance that such a coincidence occurs.&lt;/p&gt;&#xA;&lt;p&gt;EDIT: the idea of this question is similar to the approach to &lt;a href=&quot;https://www.thearchaeologist.org/blog/the-badlands-guardian-a-geomorphic-feature-or-an-ancient-geoglyph&quot; rel=&quot;nofollow noreferrer&quot;&gt;debunk&lt;/a&gt; Ley Lines by considering alignments of random points.&lt;/p&gt;&#xA;" OwnerUserId="26174" LastEditorUserId="18081" LastEditDate="2022-03-11T09:20:01.600" LastActivityDate="2022-03-11T09:20:01.600" Title="How large is the chance that the Badlands Guardian emerged from natural processes?" Tags="|geomorphology|erosion|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="23599" PostTypeId="1" AcceptedAnswerId="23603" CreationDate="2022-03-10T15:03:33.563" Score="2" ViewCount="123" Body="&lt;p&gt;I'm using a few gas sensors (MQ2, MQ3, MQ4, MQ5, MQ6, MQ7, MQ8, MQ9, and MQ135) to measure the air quality inside my home. These sensors have been calibrated to work within a specific concentration range (i.e. 200 - 10000ppm). Here's an example model from one of the datasheets:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/2tCP2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2tCP2.png&quot; alt=&quot;MQ2 Sensitivity Characteristics&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Rs = Resistance of the Sensor&lt;/p&gt;&#xA;&lt;p&gt;Ro = Resistance of the Sensor in Clean Air&lt;/p&gt;&#xA;&lt;p&gt;An Arduino reads the values from the sensor. I then convert the Rs/Ro value to PPM using y = mx + b, where y = Log(Rs/Ro) and x = Log(PPM).&lt;/p&gt;&#xA;&lt;p&gt;When concentrations are too low (&amp;lt;200ppm) or too high (&amp;gt;10000ppm), the Rs/Ro value falls outside the model. What should I do with the values that fall outside the model's range?&lt;/p&gt;&#xA;" OwnerUserId="26537" LastActivityDate="2022-03-11T07:48:30.207" Title="What to do with a gas sensor's values that fall outside of a model's range?" Tags="|models|environmental-sensors|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23600" PostTypeId="2" ParentId="23598" CreationDate="2022-03-10T16:50:22.047" Score="4" Body="&lt;p&gt;The chance that this occurs in this particular spot is indeed small. The chance that a natural face-like feature occurs &lt;em&gt;somewhere&lt;/em&gt; on the earth's hundreds of millions of square miles of land area is virtually guaranteed. Even if the chance of natural face formation in an area this size is one in a billion, it's utterly unsurprising to find a few faces scattered around the globe.&lt;/p&gt;&#xA;&lt;p&gt;I don't think you'll be able to model the geological and pattern recognition processes to generate a probabilistic estimate that's more precise than one part in a billion. There isn't any evidence to suggest that this formation is anything but natural, and unless your geological model can accurately state that the likelihood of such a face in such an area is less than 0.0000001%, we should not be surprised to find a formation that looks like a face when looking at hundreds of millions of square miles of land area. At that level of precision, variability due to your choice of assumptions for the modeling are likely to dwarf any meaningful output of the model.&lt;/p&gt;&#xA;&lt;p&gt;Pareidolia is the phenomenon of perceiving meaningful patterns where there are none. It's extremely common to see meaningful shapes in natural formations like clouds and rocks, even though the formations are natural and random. With nothing to suggest any kind of active sculpting of this formation (nothing to suggest by whom, or how, or when, or for what purpose it was sculpted), the most likely explanation is natural formation and pareidolia.&lt;/p&gt;&#xA;" OwnerUserId="4971" LastActivityDate="2022-03-10T16:50:22.047" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23603" PostTypeId="2" ParentId="23599" CreationDate="2022-03-11T07:48:30.207" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;I'll update my code to ignore the sensor readings that fall outside the calibrated range.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Do not do that. Instead flag them as off-scale low or off-scale high. Those off-scale low / off-scale high values might mean that the sensor is failing, or that the battery is about to die.&lt;/p&gt;&#xA;&lt;p&gt;Or it could just mean that the sensor gave a one-off glitchy measurement. Sensors do do this, with great regularity. It is a good idea with regard to sensor processing to have a quality flag associated with the sensor. An occasional glitchy measurement is something one should expect. Rare glitchy measurements are best ignored, but still should be tracked. An excess of isolated glitchy measurements is an indicator of sensor / battery health.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, an off-scale reading could well mean your house is about to burst into flames. Simply ignoring those off-scale readings is a bad idea.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-03-11T07:48:30.207" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23604" PostTypeId="2" ParentId="23597" CreationDate="2022-03-11T13:23:19.510" Score="6" Body="&lt;p&gt;You’re possibly thinking of the steady state descriptions, as shown in something like the Trenberth diagram below.  These are steady state descriptions of energy &lt;em&gt;flows&lt;/em&gt; rather than energy &lt;em&gt;stores&lt;/em&gt;, in which the system has already accumulated energy in various components and their states (e.g., temperatures) have already adjusted to remove any imbalance in energy flow through the system.  Even in balance energy continues to flow through the whole system, with input from the sun balanced by output from thermal emission to space at the system boundary.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dKD3g.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dKD3g.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;By NASA - &lt;a href=&quot;https://web.archive.org/web/20140421050855/http://science-edu.larc.nasa.gov/energy_budget/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://web.archive.org/web/20140421050855/http://science-edu.larc.nasa.gov/energy_budget/&lt;/a&gt; quoting Loeb et al., J. Clim 2009 &amp;amp; Trenberth et al, BAMS 2009, Public Domain, &lt;a href=&quot;https://commons.wikimedia.org/w/index.php?curid=32285340&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://commons.wikimedia.org/w/index.php?curid=32285340&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;If we changed something about that system, such as increasing atmospheric CO2, and recalculated the energy flows only, we would find that those flows no longer balance.  Each component would have a net gain or loss of energy.  At this point we could re-diagnose the states (e.g., atmosphere and surface temperatures) that would bring this system back into balance.&lt;/p&gt;&#xA;&lt;p&gt;Note there’s no component of time in this description, this is just diagnosing the initial and final states of the system in response to a given change.  Under this model we don’t need to know the details of what the surface is made of, we’re just describing it as something that radiates like a black body with a particular emissivity.  But if we want to know how the system transitions between those two balance states then, yes, we will need to know the heat capacities of the various components.  Components with larger heat capacities will take longer to transition and accumulate more energy for a given level of energy imbalance than components with smaller heat capacities.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Why is this point never mentioned in the theory? It seems to have been completely ignored.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Just taking one example climate model land surface scheme, &lt;a href=&quot;http://doi.org/10.5194/gmd-4-677-2011&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://doi.org/10.5194/gmd-4-677-2011&lt;/a&gt;, the surface heat capacity it literally the first term of the first equation in that paper.&lt;/p&gt;&#xA;&lt;p&gt;Similarly, the latest IPCC report (and many of the previous ones, and the references therein) has lots of analysis of this aspect, e.g., Fig TS.13:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Ey25c.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ey25c.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;IPCC AR6 (2021), Technical Summary (&lt;a href=&quot;https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_TS.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;pdf&lt;/a&gt;), Figure TS.13 (page TS-150).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Where does the extra energy come from? It cannot be created to suit. It can only come from the energy absorbed by the extra CO2&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Ah no, this maybe where your confusion lies.  The energy comes from the sun, which is a continual external input of energy to the Earth system.  An increase in greenhouse gas concentration causes some of that energy to accumulate in the system, changing the system state, until the state has changed to the point that input and output are back in balance.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Energy is required to increase the temperature of the surface, and more energy is required if any is to be radiated. This can only be funded by the extra energy absorbed by the extra CO2 The extra energy cannot be provided by the Sun, because its supply to the surface was already in balance with output before the addition of CO2.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Well, specifically, increasing the greenhouse gas concentration reduces the atmospheric transmittance to longwave radiation, which reduces the amount of energy leaving the atmosphere to space and increases the energy content and temperature of the atmosphere.  The warmer atmosphere emits more longwave radiation both to space (thereby weakening the initial top-of-atmosphere imbalance) and to the surface.  The latter changes the surface energy budget through the downwelling longwave term, reducing the &lt;em&gt;net&lt;/em&gt; loss of energy from the surface by longwave exchange and increasing in the energy content and temperature of the surface. But while the &amp;quot;back radiation&amp;quot; may be the route through which surface temperature increases, the sun is the origin of all the energy flowing through the diagram at the top.&lt;/p&gt;&#xA;" OwnerUserId="106" LastEditorUserId="106" LastEditDate="2022-03-14T16:06:55.107" LastActivityDate="2022-03-14T16:06:55.107" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23606" PostTypeId="1" CreationDate="2022-03-11T14:20:42.880" Score="2" ViewCount="15" Body="&lt;p&gt;We know that geochemical anomalies in stream sediment usually distributed along the drainage. Therefore, when we use stream sediment as the sampling medium and found an anomaly, we should trace the anomaly along the stream to find the origin related to the anomalies. But in the procedure of mineral prospectivity mapping (MPM) with support of GIS, we did not perform the procedure of tracing geochemical anomalies along the stream, but directly use the geochemical anomalies as an evidence layer to overlay with other type of evidence, such as geophysical anomalies, fault buffer, etc. My question is why there is no need to do the tracing step in MPM?&lt;/p&gt;&#xA;" OwnerUserId="11924" LastActivityDate="2022-03-11T14:20:42.880" Title="How should we deal with geochemical anomalies in stream sediment?" Tags="|geology|geochemistry|minerals|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23607" PostTypeId="1" CreationDate="2022-03-11T14:28:07.380" Score="4" ViewCount="159" Body="&lt;p&gt;These Basalt rocks were hand cracked and used to build the walls on my home.&lt;/p&gt;&#xA;&lt;p&gt;Many of these rocks have these semi circular pattern, made of the basalt itself. It's just a bit darker than the rest of the stone.&#xA;I am wondering what caused it. &lt;a href=&quot;https://i.stack.imgur.com/k1mgm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/k1mgm.jpg&quot; alt=&quot;Pattern on Basalt rock&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26545" LastActivityDate="2022-03-11T14:28:07.380" Title="Patterns on Basalt" Tags="|geology|rocks|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23608" PostTypeId="2" ParentId="23586" CreationDate="2022-03-12T13:54:48.353" Score="1" Body="&lt;p&gt;You are most likely seeing an effect of varying camera resolution, combined with nonuniform lighting caused by reflections off the clouds.&lt;/p&gt;&#xA;&lt;p&gt;On any planet with an atmosphere, brightness dies not drop off all at once from day to night, but decreases gradually within a range along either side of the terminator (an effect we see as twilight or, in the reverse direction each morning, as dawn).&lt;/p&gt;&#xA;&lt;p&gt;This dawn/twilight effect impacts what the camera can resolve of the atmosphere. As you approach the and pass terminator going from right to left, and the light of the sky dims, only the brightest parts are resolved and remain visible for a longer distance into the night. The layers of the atmosphere remain the same in reality but not in their lighting.&lt;/p&gt;&#xA;&lt;p&gt;Now look away from the horizon. If you have clouds mixed with clear sky you probably know that when the Sun is rising or setting it tends to reflect brightly off the clouds; the reflections from the clouds are brighter than the surrounding sky (and the shadowed regions of those clouds).&lt;/p&gt;&#xA;&lt;p&gt;Again, in your picture, you have slowly fading brightness as you go to the left and also clouds whose reflections have locally increased brightness. Apparently the clouds may be reflecting brightly enough for the camera to pick then up relatively far past the terminator, whereas the cloud-free areas get too dim at a shorter distance.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2022-03-12T20:36:32.253" LastActivityDate="2022-03-12T20:36:32.253" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23609" PostTypeId="1" AcceptedAnswerId="23610" CreationDate="2022-03-12T15:26:46.357" Score="6" ViewCount="315" Body="&lt;p&gt;Can we imagine a large laser beam that sends energy into space in the form of light? (long wave infra red? Or another wave length that goes all the way through the atmosphere). If we were to feed this big beam with electricity made of ambiant energy (not fossil fuel, not nuclear), would this contribute to reducing the heat on earth?&lt;/p&gt;&#xA;&lt;p&gt;It would look like a massive waste of energy, but from a pure system perspective, such a waste would be a way to reach an equilibrium. We would essentially be dumping into space the extra energy we have imported into the system by burning fossil fuel.&lt;/p&gt;&#xA;&lt;p&gt;Please point it out if I am voicing thermodynamics profanities or why such apparatus would be technically not achievable.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Disclaimer: I am not a phycicist nor an engineer. I trust experts help us focus on what is the most effective way to fight climate change, which is to reduce the greenhouse effect by cutting down on emissions of CO2, methane and the like. I ask this question humbly because I am genuinely curious to fill in some gaps in my understanding of thermodynamics and nurturing this curiosity prevents me from becoming cynical or pessimistic. Sorry if my question is dumb or grotesquely science-fictionish&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="26549" LastEditorUserId="6467" LastEditDate="2022-03-12T16:15:08.727" LastActivityDate="2023-11-16T22:03:33.780" Title="Can we beam heat into space?" Tags="|geoengineering|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23610" PostTypeId="2" ParentId="23609" CreationDate="2022-03-13T13:00:17.393" Score="7" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;If we were to feed this big beam with electricity, would this contribute to reducing the heat on earth?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;No.&lt;/p&gt;&#xA;&lt;p&gt;The Earth's energy imbalance is estimated to be 0.77 watts per square meter. Multiplied by the Earth's surface area, that is equivalent to 393 terawatts. The electrical energy generated by all of humanity is about 25000 terawatt hours per year. Dividing by a year yields 2.85 terawatts.&lt;/p&gt;&#xA;&lt;p&gt;This factor of greater than 100 discrepancy does not account for how incredibly energy inefficient most lasers are. Multiply that factor of more than 100 discrepancy by at least five (and that's assuming 20% efficiency, which is a bit high). We would need to ramp up electricity generation by a huge amount to make even a small dent in the Earth's energy imbalance by beaming energy into space via lasers.&lt;/p&gt;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021GL093047&quot; rel=&quot;noreferrer&quot;&gt;Norman G. Loeb, et al. &amp;quot;Satellite and ocean data reveal marked increase in Earth’s heating rate.&amp;quot; Geophysical Research Letters 48.13 (2021): e2021GL093047.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://yearbook.enerdata.net/electricity/world-electricity-production-statistics.html&quot; rel=&quot;noreferrer&quot;&gt;yearbook.enerdata.net, World Energy &amp;amp; Climate Statistics – Yearbook 2021.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://phys.org/news/2007-07-laser-power-energy-efficiency.html&quot; rel=&quot;noreferrer&quot;&gt;phys.org, Laser sets records in power and energy efficiency.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-03-13T13:00:17.393" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23612" PostTypeId="1" CreationDate="2022-03-14T00:27:13.187" Score="3" ViewCount="357" Body="&lt;p&gt;&lt;a href=&quot;https://astronomy.stackexchange.com/q/48795/7982&quot;&gt;This answer to &lt;em&gt;Salinity of Martian water 3.5 Billion years ago&lt;/em&gt;&lt;/a&gt; in Astronomy says that most estimates of Mars' ocean's salinity are pretty high;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The article &lt;a href=&quot;https://www.science.org/doi/abs/10.1126/science.1155432&quot; rel=&quot;nofollow noreferrer&quot;&gt;&amp;quot;Water Activity and the Challenge for Life on Early Mars&amp;quot;&lt;/a&gt; finds that the early martian ocean would have been acidic and almost as salty as the dead sea.&lt;/p&gt;&#xA;&lt;p&gt;The estimates for salinity of the europan ocean vary widely, but most place the salinity &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0019103507000656&quot; rel=&quot;nofollow noreferrer&quot;&gt;above 50g/kg&lt;/a&gt;, more than that of sea water (about 45 g/kg).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I've commented there the possibility that:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;those estimates may change as more is learned about Mars&lt;/li&gt;&#xA;&lt;li&gt;there could be regional variations in surface water salinity since there is believed to have been rain, and tidal mixing may have been much less than on Earth&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;I support my amateur hypothesis in item 2 with the following&lt;/p&gt;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;Mars has no massive moon like the Earth's&lt;/li&gt;&#xA;&lt;li&gt;Mars's orbit is about 1.67 times further from the Sun than Earth on average, and tidal accelerations vary as &lt;span class=&quot;math-container&quot;&gt;$1/r^3$&lt;/span&gt; putting the tidal acceleration at 22% of what Earth experiences at 1 AU.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;However we should remember that &lt;em&gt;Mars' surface gravity&lt;/em&gt; is only 38% of that on Earth, so the effect is not reduced as much as one might first think.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; How large were Mars' ocean tides and to what extent could they keep the oceans mixing and tend to keep salinity uniform? Can this at least be estimated, and has this been modeled?&lt;/p&gt;&#xA;&lt;p&gt;Potentially related:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/19979/6031&quot;&gt;Is it possible to predict the maximum daily/annual tide height without calculating hourly heights?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2022-03-14T13:06:57.903" LastActivityDate="2022-03-15T23:37:02.000" Title="How large were Mars' ocean tides and to what extent could they keep the oceans mixing and tend to keep salinity uniform? Has this been modeled?" Tags="|oceanography|ocean-currents|tides|mars|ocean-models|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23613" PostTypeId="1" CreationDate="2022-03-14T20:46:46.837" Score="1" ViewCount="26" Body="&lt;p&gt;Water transports heat from the surface of the earth to the upper atmosphere by evaporation, which cools the surface, and then condensing at cloud height, where it releases latent heat. So water decreases the temperature gradient, and in the process expands the atmosphere so that it reaches a greater height. I am wondering if this takes a significant amount of energy to raise the atmosphere to greater heights, and if so does that take away from some of the energy that goes to global warming?&lt;/p&gt;&#xA;" OwnerUserId="26555" LastActivityDate="2022-03-14T21:22:34.757" Title="Does absorbed energy from sun go to increasing atmosphere's height, as well as heating earth up?" Tags="|meteorology|climate|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23615" PostTypeId="2" ParentId="23612" CreationDate="2022-03-14T21:24:04.547" Score="-1" Body="&lt;p&gt;It's hard to model tidal influence of such minor moons....on a small planet&#xA;While Mars had water in its ancient past....how much is a substantial mystery.&#xA;Solar tidal actions would be even weaker....&lt;/p&gt;&#xA;" OwnerUserId="21028" LastEditorUserId="21028" LastEditDate="2022-03-15T23:37:02.000" LastActivityDate="2022-03-15T23:37:02.000" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23616" PostTypeId="2" ParentId="19667" CreationDate="2022-03-14T21:30:30.707" Score="0" Body="&lt;p&gt;Hawaii s a chain island made of various continuous eruptions. It's like a conveyor belt. As the hotspot deposited lava cooling under the sea..... the island would form.....as the Pacific plate moved....the hot spot remains in position and starts over. Some mountains never made it to the surface.... Hawaiian chain is over 26 million years old.....but its youngest island is only half a million.....and 2600 miles if islands that after millions of years eroded into the small atolls [midway, etc.] You see now.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/N9sZT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/N9sZT.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastEditorUserId="21028" LastEditDate="2022-03-16T04:55:36.163" LastActivityDate="2022-03-16T04:55:36.163" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23617" PostTypeId="2" ParentId="23612" CreationDate="2022-03-15T15:05:48.643" Score="2" Body="&lt;p&gt;I will attempt a partial answer.&lt;/p&gt;&#xA;&lt;p&gt;A search of Web of Knowledge finds that most of the papers addressing Martian tides either focus on &lt;a href=&quot;https://eos.org/research-spotlights/capturing-heat-driven-atmospheric-tides-on-mars&quot; rel=&quot;nofollow noreferrer&quot;&gt;atmospheric tides and their role in Martian weather&lt;/a&gt; or what current Martian surface tides can tell us about the interior structure of Mars.&lt;/p&gt;&#xA;&lt;p&gt;One such paper from last year, &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021EA001669&quot; rel=&quot;nofollow noreferrer&quot;&gt;Forward Modeling of the Phobos Tides and Applications to the First Martian Year of the InSight Mission&lt;/a&gt;, highlights the difficulty of distinguishing how much the moon Phobos contributes to Martian tides vs. the massive contribution of the sun. (Mars, of course, currently has two moons, Phobos and the much smaller Deimos, both much smaller than Earth's moon.)&lt;/p&gt;&#xA;&lt;p&gt;Estimates about tidal mixing in an early Martian ocean would be complicated by a variety of uncertainties: When was there an ocean on Mars? How large was it? While the Sun's gravitational effects would have been constant, I don't think we yet know if Mars always had a moon or moons and how large were they at the time surface water would have been present. There is still a debate about the history of Phobos and Deimos. (See: &lt;a href=&quot;https://www.sciencedaily.com/releases/2016/07/160704144236.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;A giant impact: Solving the mystery of how Mars' moons formed&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;As you note in your question and Jean-Marie Prival noted in a comment, there are other drivers of ocean mixing other than tides, such as the water cycle of evaporation and precipitation, centrifugal force from planetary spin (in the posited north polar ocean), and winds (though Mars' atmosphere is thin). (See &lt;a href=&quot;https://www.space.com/28983-ancient-mars-oceans-big-waves.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ancient Mars May Have Had Slow-Moving Monster Waves&lt;/a&gt;.)&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2022-03-15T15:05:48.643" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23618" PostTypeId="1" CreationDate="2022-03-15T16:09:33.460" Score="3" ViewCount="117" Body="&lt;p&gt;If I have a body that is exposed to light of intensity &lt;span class=&quot;math-container&quot;&gt;$I$&lt;/span&gt;, then its temperature should follow the ODE&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\dot{T} = a I - b T^4$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Mountains are covered with snow, yet &lt;span class=&quot;math-container&quot;&gt;$I$&lt;/span&gt; should be the same as at sea level (or slightly higher becuase there is less stuff to pass through). Lower pressure means lower temperature, but that shouldn't affect the rock surface temperature.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;How does temperature at elevation z depend on temperature at level z0. I think the classic graph showing decreasing temperatures show an average. I wonder what it looks like if you change sea level temperature&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;What effect causes the mountain top to cool off. Is it mainly wind? Note: lesser dense atmosphere should make the surface hotter because of higher isolation. I guess&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial T}{\partial t } = D\nabla^2T$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;With boundary condition&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\dot{T}_\text{surface} = a I - b T_\text{surface}^4$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;But &lt;span class=&quot;math-container&quot;&gt;$D$&lt;/span&gt; is lower at lower air densities, thus the mountain surface should have a higher temperature.&lt;/p&gt;&#xA;" OwnerUserId="601" LastActivityDate="2022-03-16T16:12:28.057" Title="Modelling atmospheric temperature as function of elevation" Tags="|meteorology|temperature|climate-models|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23619" PostTypeId="2" ParentId="23618" CreationDate="2022-03-16T00:14:23.747" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Lower pressure means lower temperature, but that shouldn't affect the rock surface temperature&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is ignoring the fact that the rock surface exchanges temperature with the atmosphere constantly, so they should be in an approximate equilibrium on an annual time scale.&lt;/p&gt;&#xA;" OwnerUserId="56" LastActivityDate="2022-03-16T00:14:23.747" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23620" PostTypeId="1" CreationDate="2022-03-16T08:39:35.263" Score="4" ViewCount="107" Body="&lt;p&gt;I've been working with ICON, ICON-EU and GFS forecasts, and it seems like the temperature results are &amp;quot;close&amp;quot; for the same location, 6 hour forecasts and 120 hour forecasts - MAE: 5.7 and 6.87 respectively. Is it usually the case and if it is, I would like to find out the reasons briefly.&lt;/p&gt;&#xA;&lt;p&gt;I'm fetching forecasts from global models every 6 hours. Forecasts are in the range of 0-144 hours, hourly incremented. I calculated the error metric by using only 6 hour forecasts vs 120 hour forecasts.&lt;/p&gt;&#xA;&lt;p&gt;Dataset example below:&#xA;You can see that models forecast the next 144 hours in every run and I fetch every 6 hours so base_run_timestamp increments every 6 hours.&#xA;(Base_run_timestamp is when the models made their forecasts and forecasted_timestamp is pretty self-explanatory)&lt;/p&gt;&#xA;&lt;p&gt;Note: I realized this is a consistent error for my observation point, I applied simple linear regression and the error went straight down to ~1°C so high error is irrelevant.&lt;/p&gt;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dkDEM.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dkDEM.png&quot; alt=&quot;DS_1&quot; /&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/I6RA3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/I6RA3.png&quot; alt=&quot;DS_2&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26561" LastEditorUserId="26561" LastEditDate="2022-04-21T12:40:00.993" LastActivityDate="2022-04-21T12:40:00.993" Title="How much does a global model's accuracy change with the timestep?" Tags="|meteorology|temperature|weather-forecasting|gfs|" AnswerCount="0" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="23621" PostTypeId="2" ParentId="16377" CreationDate="2022-03-16T09:56:37.430" Score="3" Body="&lt;p&gt;The uncertainty on the decay constant / half life is systematic. This means that, if the &amp;quot;used&amp;quot; value would be off the &amp;quot;true&amp;quot; value by 0.05%, then it would affect all the ages in the same way (e.g. either too old by 0.05% or too young by 0.05%, depending on which way the error is).&lt;/p&gt;&#xA;&lt;p&gt;Effectively, if one is comparing differences between zircon U-Pb dates collected using the same decay constant, the systematic uncertainties such as half life can be ignored, as the duration does not change significantly. Just the absolute age value.&#xA;The reporting of uncertainties in the paper by Burgess et al. you describe is described in detail in the bottom of the second page. They clearly state:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Uncertainties associated with weighted mean 206Pb/238U dates are&#xA;reported as ±x/y/z, where x is the analytical (internal) uncertainties&#xA;and y and z include the systematic uncertainties associated with&#xA;tracer calibration (0.03%) and 238U decay constant (0.05%),&#xA;respectively. If calculated dates are to be compared with other U-Pb&#xA;laboratories not using the EARTHTIME tracer, then ±y should be used&#xA;for each laboratory. If compared with other chronometers such as Ar-Ar&#xA;or astrochronology, then ±z should be used.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="4783" LastActivityDate="2022-03-16T09:56:37.430" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23622" PostTypeId="1" CreationDate="2022-03-16T11:46:13.890" Score="1" ViewCount="32" Body="&lt;p&gt;Can someone clarify me about this doubt?&lt;/p&gt;&#xA;&lt;p&gt;Is the available soil water content (field capacity minus wilting point) the same as the soil water moisture or soil water content?&lt;/p&gt;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="26563" LastActivityDate="2022-03-16T11:46:13.890" Title="soil water retention and soil water content" Tags="|water|soil-science|soil-moisture|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23623" PostTypeId="1" CreationDate="2022-03-16T14:40:57.167" Score="3" ViewCount="193" Body="&lt;p&gt;The Stockholm Resilience Center created a report about &amp;quot;&lt;a href=&quot;https://www.stockholmresilience.org/research/planetary-boundaries/the-nine-planetary-boundaries.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;The nine planetary boundaries&lt;/a&gt;&amp;quot;. In it, they claim that Nitrogen and phosphorus flows to the biosphere and oceans are very strongly over the planetary boundary and thus very dangerous.&lt;/p&gt;&#xA;&lt;p&gt;How dangerous is it to have those flows at current levels? In what kind of timeframe do we see damage if we don't stop the problem?&lt;/p&gt;&#xA;" OwnerUserId="22756" LastActivityDate="2022-03-18T22:24:41.437" Title="How big of an issue are Nitrogen and phosphorus flows to the biosphere and oceans?" Tags="|nitrogen|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23624" PostTypeId="2" ParentId="23618" CreationDate="2022-03-16T16:06:54.693" Score="4" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;If I have a body that is exposed to light of intensity &lt;span class=&quot;math-container&quot;&gt;$I$&lt;/span&gt;, then its temperature should follow the ODE&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\dot{T} = a I - b T^4$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You are implicitly assuming the Earth's surface is radiating into empty space. The Earth's surface doesn't &amp;quot;see&amp;quot; empty space in the thermal infrared. It instead &amp;quot;sees&amp;quot; an atmosphere that is much warmer than empty space in the thermal infrared, typically about 10 °C to 20 °C cooler than the surface. You are failing to account for the back radiation from the atmosphere.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Lower pressure means lower temperature, but that shouldn't affect the rock surface temperature.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;That atmospheric temperature in the troposphere decreases with increasing altitude does affect rock surface temperature. This is the primary reason mountaintops and high elevation plateaus are cool.&lt;/p&gt;&#xA;&lt;p&gt;However, consider the Tibetan Plateau. The daily mean temperature in Lhasa (altitude = 3656 meters) is 8.8 °C. A naive application of the environmental lapse rate of 6.5 °C per kilometer would suggest Lhasa's mean temperature should be about 24 °C cooler than that of locales at the same latitude but at sea level. Lhasa is indeed cooler than those corresponding sea level locales, but not by 24 °C. Lhasa instead is only about 11 to 13 °C cooler than those corresponding sea level locales. In fact, &lt;a href=&quot;https://scholar.google.com/scholar?hl=en&amp;amp;q=Heating+Effect+of+the+Tibetan+Plateau&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Tibetan Plateau acts as a significant heat source for the upper troposphere&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2022-03-16T16:12:28.057" LastActivityDate="2022-03-16T16:12:28.057" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23625" PostTypeId="1" AcceptedAnswerId="23626" CreationDate="2022-03-17T06:44:11.453" Score="10" ViewCount="1901" Body="&lt;p&gt;I was talking to a friend of mine who is an environmentalist like me but not a big fan of nuclear power and she told me it was not a good option in the long run because of the decay of uranium. Of course this is a ridiculous argument because U-238's half-life is measured in billions of years, but nonetheless I couldn't tell her whether or not the world's reserves were shrinking in a geologic time scale. Looking at the many decay elements of U-238, I believe there may be a handful of isotopes that decay into it. And I'm &lt;em&gt;certain&lt;/em&gt; there is a name for these elements I'm looking for, I just can't find them.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Follow-up question:&lt;/strong&gt; given our current known reserves of transuranic elements and again taking into account their decay products, where will the greatest uranium reserves be in, say, 10 half-lives of U-238? I can barely make sense of a nuclide chart and don't even know where to begin looking for a map of these elements.&lt;/p&gt;&#xA;" OwnerUserId="26564" LastActivityDate="2022-03-28T15:59:44.580" Title="Taking into account the decay products of transuranic elements, are the world's uranium reserves growing or shrinking?" Tags="|geophysics|geochemistry|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23626" PostTypeId="2" ParentId="23625" CreationDate="2022-03-17T11:27:32.040" Score="22" Body="&lt;p&gt;Let's start with the easy question:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;given our current known reserves of transuranic elements and again taking into account their decay products, where will the greatest uranium reserves be in, say, 10 half-lives of U-238? I can barely make sense of a nuclide chart and don't even know where to begin looking for a map of these elements.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;10 half lives of U-238 will pass in around 45 billion years. We have only about 5 billion years before the sun starts expanding beyond Earth's orbit. Therefore, the answer to your question is &amp;quot;inside the sun&amp;quot;.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Now, the main part of your question:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Of course this is a ridiculous argument because U-238's half-life is&#xA;measured in billions of years&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You are entirely correct. We can even calculate that. Let's &lt;a href=&quot;https://www.wolframalpha.com/input?i=decay%20of%20uranium%20after%201000%20years&quot; rel=&quot;noreferrer&quot;&gt;ask Wolfram Alpha&lt;/a&gt; how much uranium will have decayed after 1000 years. This is the answer:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;remaining fraction of number of particles | 99.9999845%&#xA;= 0.999999845&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So for all practical purposes, after one thousand years (!!), the amount of uranium in the Earth does not change (other than the uranium used for power generation).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;I couldn't tell her whether or not the world's reserves were shrinking&#xA;in a geologic time scale&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;First, note that the word &amp;quot;reserves&amp;quot; has a &lt;a href=&quot;https://en.wikipedia.org/wiki/Mineral_resource_classification#Mineral_Reserves&quot; rel=&quot;noreferrer&quot;&gt;very specific meaning&lt;/a&gt;. You are probably asking simply about the quantity of uranium in the Earth. So yes, it is shrinking. The half-life of uranium is about 4.5 billion years, which happens to be the age of the earth. So the Earth currently has half of the uranium it had when it first formed.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;I believe there may be a handful of isotopes that decay into it&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Yes, Pu-242 will decay to U-238 with a half-life of 375000 years. Since we're more than 100 half-lives past the formation of the Earth, there is no Pu-242 left on Earth for all practical purposes. Statistically speaking, there might be a few atoms left hanging around since then, but don't put your bets on their decay for increasing the amount of U-238.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2022-03-17T11:27:32.040" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="23627" PostTypeId="1" CreationDate="2022-03-17T14:48:43.820" Score="2" ViewCount="434" Body="&lt;p&gt;If you take a cilindrical section with radius 1 meter of both kinds of plate, which will have a larger mass?&#xA;My guess is that continental plates are heavier than oceanic plates, because they are &lt;a href=&quot;https://lisbdnet.com/how-thick-are-tectonic-plates/#How_Thick_Are_Tectonic_Plates&quot; rel=&quot;nofollow noreferrer&quot;&gt;more than twice as thick&lt;/a&gt; while their densities are similar. Is this correct? Are there other factors than thickness and density which contribute to the mass?&lt;/p&gt;&#xA;" OwnerUserId="26174" LastEditorUserId="26174" LastEditDate="2022-03-27T18:36:26.500" LastActivityDate="2022-03-27T18:36:26.500" Title="Are oceanic plates or continental plates heavier?" Tags="|plate-tectonics|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23628" PostTypeId="2" ParentId="23623" CreationDate="2022-03-17T18:56:45.017" Score="0" Body="&lt;p&gt;I can think of two separate answers.&lt;/p&gt;&#xA;&lt;p&gt;‏Eutrophication is one of the most prominent pollution causes in the marine and riparian environments. It leads to anoxia and suffocation save of complete habitats ‏and caused by axis nitrogen and phosphorus.&lt;/p&gt;&#xA;&lt;p&gt;Unlike nitrogen, phosphorus is scarce. Many think that we might run out and when we do, we will not be able to grow enough crops to sustain the population.&lt;/p&gt;&#xA;" OwnerUserId="20249" LastEditorUserId="20249" LastEditDate="2022-03-18T22:24:41.437" LastActivityDate="2022-03-18T22:24:41.437" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23629" PostTypeId="2" ParentId="23623" CreationDate="2022-03-18T02:33:01.867" Score="1" Body="&lt;p&gt;Eutrophication is an issue...namely because of red tides, algal blooms and anoxic water.... However practical solutions. However influxes of fertilizer is often dealt with. For decades scientists have been investigating healthier and smarter alternatives to conventional wastewater treatment systems and agricultural runoffs. Dr. John Todd developed bioremediation systems, &amp;quot;Living Machines&amp;quot; where solar dynamics, water dilution and organic waste handling. Now, Small towns; instead of being dumping grounds for big city waste, they can produce valuable products (Plants, flowers, fruits, fish, clams, oysters)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DKRwB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DKRwB.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2022-03-18T02:33:01.867" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23630" PostTypeId="2" ParentId="23625" CreationDate="2022-03-18T05:30:15.017" Score="2" Body="&lt;p&gt;The uranium present on Earth is always decreasing (barring a big delivery by an impact event--and radioactivity would be the least of our concerns then.)  Yes, uranium appears in some of the decay chains--but the only naturally occurring top of those decay chains is uranium.&lt;/p&gt;&#xA;&lt;p&gt;Yes, you can find decay chains listed with something else at the top, but that something else is either synthetic or originally came from uranium.&lt;/p&gt;&#xA;&lt;p&gt;If you want to look at geological time scales you'll find nuclear power reduces radioactivity.  All the radioactivity it produces is reasonably short lived, mining and using up the uranium will eventually show up as reduced radon exposure as all radon is produced by uranium decay.&lt;/p&gt;&#xA;" OwnerUserId="1160" LastActivityDate="2022-03-18T05:30:15.017" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23631" PostTypeId="2" ParentId="23627" CreationDate="2022-03-18T10:57:28.327" Score="6" Body="&lt;p&gt;You're saying...&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;My question is not about the density&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;But then...&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;So if you take for example a cilindrical section with radius 1 meter&#xA;of both kinds of plate, which will have a larger mass?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;And since density is mass divided by volume, your question &lt;em&gt;is&lt;/em&gt; about density.&lt;/p&gt;&#xA;&lt;p&gt;To answer your question - the plates &amp;quot;weigh&amp;quot; about the same. They have to be. If one plate is heavier, it will sink and displace the underlying mantle so that it pushes the lighter plate upwards. Note that these things actually happen - the Earth is not in dynamic equilibrium and various tectonic and surface processes cause this disequilibrium and movement.&lt;/p&gt;&#xA;&lt;p&gt;But there isn't anything inherently heavier about the oceanic plate compared to the continental plate, or vice versa, when taken as a whole. This is the concept of isostasy (&lt;a href=&quot;https://en.wikipedia.org/wiki/Isostasy&quot; rel=&quot;noreferrer&quot;&gt;with a well illustrated Wikipedia page&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;And pay attention to what you're talking about the continental and oceanic &lt;em&gt;&lt;strong&gt;plate&lt;/strong&gt;&lt;/em&gt; or the continental and oceanic &lt;em&gt;&lt;strong&gt;crust&lt;/strong&gt;&lt;/em&gt;. The two are not the same. It is correct that the continental crust is about double (or more!) than the thickness of the oceanic crust, but the continental plate is not double the thickness of the oceanic plate. The plate includes the crust and the upper mantle - together called the &amp;quot;lithosphere&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2022-03-18T10:57:28.327" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="23633" PostTypeId="1" CreationDate="2022-03-22T00:08:20.457" Score="2" ViewCount="57" Body="&lt;p&gt;According to a trial, Olives grown under well lit conditions, with respect to those grown at low light intensity, were heavier, had a higher percentage of oil and a lower water content.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.actahort.org/books/949/949_35.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.actahort.org/books/949/949_35.htm&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;The influence of light availability on olive fruit development, oil accumulation and the qualitative characteristics of the oil were studied. The trial was carried out in central Italy, on non-irrigated trees of cultivars ‘Frantoio’ and ‘Leccino’. In October and November, samples of olives grown under conditions of low or high light availability (about 400 and 1100 μmol of photons m-2 s-1) were collected and analysed. Fruit ripening was slightly affected by high availability of light (higher pigmentation and detachment force and lower pulp consistency). Olives grown under well lighted conditions, with respect to those grown at low light intensity, were heavier, had a higher percentage of oil and a lower water content. The pulp/pit ratio was not affected by light intensity. The oils extracted from olives grown under high light conditions had a higher polyphenol content and better sensorial characteristics than those obtained from olives grown at low light intensity. The acidity and peroxide number were not affected by the light conditions. The results highlight the importance of ensuring good, uniform illumination of the entire crown by making optimal choices at the moment of the olive orchard establishment and rationalizing all techniques that affect light availability at the crown level (planting area exposition, training system and spacing, pruning intensity, etc.).&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;my question&lt;/strong&gt;: was it known before this trial (among people in past times), that olive trees produce better, finer harvests e.g. oil etc .. if located in a place where the trees has more exposure to sunlight?&lt;/p&gt;&#xA;" OwnerUserId="26585" LastEditorUserId="2470" LastEditDate="2022-03-22T02:05:26.953" LastActivityDate="2022-03-22T02:05:26.953" Title="Did people in ancient times know of the influence that light availability had on olive fruit development &amp; oil accumulation?" Tags="|agriculture|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23634" PostTypeId="1" CreationDate="2022-03-22T03:01:54.297" Score="2" ViewCount="878" Body="&lt;p&gt;I was looking up something about the 528 Hz frequency that people like to talk about, and some of the evidence used to support the idea seemed a little irrelevant. Like, of course the sun emits 528 Hz light (as well as like the whole visible spectrum and out both sides). Is there something else about the sun that is 528 Hz specifically?&lt;/p&gt;&#xA;&lt;p&gt;Do bees really buzz at 528 Hz? Obviously wing length would be a factor in deciding how fast they buzz.&lt;/p&gt;&#xA;&lt;p&gt;Does the golden ratio have any discernable relation to 528 Hz? The golden ratio does appear in nature, so a connection there would certainly have some weight.&lt;/p&gt;&#xA;&lt;p&gt;Are there any studies on harmonics within cellular structure at all, let alone determining that 528 Hz has anything to do with it?&lt;/p&gt;&#xA;&lt;p&gt;These are some examples of what I'm looking for. Not random coincidences or things that naturally include 528, but specific things that require exactly 528 to operate properly or tend to be normally around 528 (in the bell curve at least).&lt;/p&gt;&#xA;" OwnerUserId="26587" LastEditorUserId="26587" LastEditDate="2022-03-22T03:07:15.997" LastActivityDate="2022-03-22T03:07:15.997" Title="Specific cases of 528 Hz harmonics that appear in nature that are not wideband radiation or noise?" Tags="|geophysics|geobiology|" AnswerCount="0" CommentCount="7" ClosedDate="2022-03-24T10:56:51.863" ContentLicense="CC BY-SA 4.0" />
  <row Id="23636" PostTypeId="1" CreationDate="2022-03-22T15:21:39.500" Score="4" ViewCount="42" Body="&lt;p&gt;The WHO's &lt;a href=&quot;https://www.who.int/health-topics/air-pollution&quot; rel=&quot;nofollow noreferrer&quot;&gt;landing page on air pollution&lt;/a&gt; includes three different estimates of deaths due to air pollution:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;7 million total&lt;/li&gt;&#xA;&lt;li&gt;4.2 million due to outdoor (ambient) air pollution&lt;/li&gt;&#xA;&lt;li&gt;3.8 due to household (indoor) air pollution&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Obviously, &lt;code&gt;7 &amp;lt; 4.2 + 3.8&lt;/code&gt;, so there must be some way in which they decide some of those deaths were caused by a combination of indoor and outdoor air pollution. &lt;strong&gt;But what is this methodology?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;It's unclear where that 7 million figure originates from, so there's a chance it's a case of &lt;a href=&quot;https://xkcd.com/978/&quot; rel=&quot;nofollow noreferrer&quot;&gt;citogenesis&lt;/a&gt;, and someone just did the math wrong. It appears in WHO's 2021 &lt;a href=&quot;https://www.who.int/publications/i/item/9789240034228&quot; rel=&quot;nofollow noreferrer&quot;&gt;global air quality guidelines&lt;/a&gt; (section 1.3.3), which cites &lt;a href=&quot;https://www.who.int/airpollution/data/AAP_BoD_results_May2018_final.pdf?ua=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Burden of disease from ambient air pollution for 2016&lt;/a&gt;, where the 7 million figure &lt;em&gt;does not&lt;/em&gt; appear.&lt;/p&gt;&#xA;" OwnerUserId="7741" LastEditorUserId="7741" LastEditDate="2022-03-23T14:41:08.207" LastActivityDate="2022-03-24T13:58:07.650" Title="How does the WHO calculate the interaction of mortality effects from indoor and outdoor air pollution?" Tags="|air-pollution|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23637" PostTypeId="2" ParentId="23636" CreationDate="2022-03-24T13:58:07.650" Score="2" Body="&lt;p&gt;WHO page &lt;a href=&quot;https://www.who.int/data/gho/data/indicators/indicator-details/GHO/ambient-and-household-air-pollution-attributable-death-rate-(per-100-000-population)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Indicator 3.9.1: Mortality rate attributed to household and ambient air pollution (per 100 000 population)&lt;/a&gt; has this information in the &amp;quot;metadata&amp;quot; tab:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Method of estimation:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;[...]&#xA;To estimate the combined effects of risk factors, a joint population attributable fraction is calculated, as described in Ezzati et al (2003).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1016/S0140-6736(03)13968-2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ezzati et al (2003)&lt;/a&gt; defined the joint &lt;a href=&quot;https://www.who.int/data/gho/indicator-metadata-registry/imr-details/1287&quot; rel=&quot;nofollow noreferrer&quot;&gt;population attributable fraction&lt;/a&gt; (&lt;span class=&quot;math-container&quot;&gt;$PAF$&lt;/span&gt;) for &lt;span class=&quot;math-container&quot;&gt;$n$&lt;/span&gt; biologically independent and uncorrelated risk factors, as (their equation 2):&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$PAF = 1 - \prod_{i=1}^n(1-PAF_i)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$PAF_i$&lt;/span&gt; is the population attributable fraction of individual risk factors.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2022-03-24T13:58:07.650" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23640" PostTypeId="2" ParentId="23627" CreationDate="2022-03-25T22:07:33.500" Score="1" Body="&lt;p&gt;@gimelist answered the question in a technical sense, but if you are interested in whether the material that makes up the continents is more or less dense than the material that makes up oceanic plates, then the answer is that the material in oceanic plates is &lt;em&gt;more dense&lt;/em&gt; than the material of continental plates.&lt;/p&gt;&#xA;&lt;p&gt;In a cartoonish way, we tend to think of continents as the &amp;quot;soap scum&amp;quot; that floats on the rest of the earth. It is lighter than the rest of the material, and so whenever a continental and an oceanic plate meet, the oceanic plate generally subducts and the continent overrides.&lt;/p&gt;&#xA;&lt;p&gt;In concrete terms, the density of the basalt that makes up most of the oceanic plates is 2.9 g/cm^3, whereas the granite that makes up most of the continents has a density of 2.7 g/cm^3.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2022-03-25T22:07:33.500" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23641" PostTypeId="1" CreationDate="2022-03-25T22:59:12.940" Score="1" ViewCount="54" Body="&lt;p&gt;I am going hunting for iron ore in Switzerland and the plan is to visit some old abandoned mines in the Jura mountains. I am not quite sure exactly what I am looking for though, in the past I have found a lot of magnetite in other countries, but I do not think that is present here.&lt;/p&gt;&#xA;&lt;p&gt;In a report by the USGS I found the following passage:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Jura Mountains -- In the Jura Mountains of western Switzerland are&#xA;found the so-called &amp;quot;Bohnerze&amp;quot; -- pisolitic ores derived from Mesozoic&#xA;iron-bearing limestones by superficial disintegration during the&#xA;Eocene epoch. They are low-grade, slightly titaniferous ores which&#xA;contain 42 per cent of iron after washing.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;What does this kind of &amp;quot;Bohnerze&amp;quot; ore actually look like, and how would I best find it? Will the ore be magnetic?&lt;/p&gt;&#xA;" OwnerUserId="15244" LastActivityDate="2022-03-26T05:49:07.760" Title="&quot;Bohnerze&quot; pisolitic ore in Switzerland" Tags="|limestone|ore|iron|mesozoic|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23642" PostTypeId="1" CreationDate="2022-03-26T00:20:07.087" Score="3" ViewCount="50" Body="&lt;p&gt;Suppose that we reran Earth from two billion years ago changing the position of one atom. Would the continents drift to positions completely different from those today?&lt;/p&gt;&#xA;" OwnerUserId="26603" LastActivityDate="2022-03-26T00:20:07.087" Title="Is continental drift a chaotic phenomenon?" Tags="|fluid-dynamics|planetary-formation|continent|chaos|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23643" PostTypeId="2" ParentId="23641" CreationDate="2022-03-26T05:49:07.760" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://www.mindat.org/min-708.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bohnerz&lt;/a&gt; is the German word for &amp;quot;bean ore&amp;quot;. Another translation is &amp;quot;&lt;a href=&quot;https://www.researchgate.net/publication/238682786_Origin_of_Iron_Ore_Nuggets_Bohnerze_through_Weathering_of_Basalt_as_Documented_by_Pebbles_from_the_Herbstlabyrinth_Breitscheid-Germany&quot; rel=&quot;nofollow noreferrer&quot;&gt;nuggets&lt;/a&gt;&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;You might like to try the &lt;a href=&quot;https://www.myswitzerland.com/en-ch/experiences/pisolitic-iron-ore-in-the-wangen-valley/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wangen Valley in Switzerland&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Pisolitic iron deposits consist of small pebbles that are roughly pea shaped and similar in size to peas. The individual pebbles formed as concretions. The picture below shows &lt;a href=&quot;https://de.wikipedia.org/wiki/Bohnerz&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bean ore from a gravel plant near Genkingen/Swabian Alb&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YmFWI.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YmFWI.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-03-26T05:49:07.760" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23644" PostTypeId="2" ParentId="23625" CreationDate="2022-03-27T10:10:38.043" Score="0" Body="&lt;p&gt;The question in itself is flawed.&lt;/p&gt;&#xA;&lt;p&gt;It begins to talks about nuclear power and then focuses on U-238. The overwhelming majority of nuclear power plants today depend on U-235 which is rare. Plants using different technologies have been hampered by a mix of technical and political issues. Such is the political pressure that, chances are, we will remain with the current PWR technology for a very long time.&lt;/p&gt;&#xA;&lt;p&gt;Since U-235 is needed also as a trigger in the other types of nuclear plants chances are that an eventual switch to heavy water or breeder reactors might start when it will be too late. It would be still possible to produce Nuclear energy with U-238 using particle accelerators to generate neutron beams and bombard the Uranium, but at a high cost, proposed designs never went beyond the drawing board.&lt;/p&gt;&#xA;&lt;p&gt;So, the problem in the long will be the exhaustion of a finite resource way long before the decay could have any impact.&lt;/p&gt;&#xA;" OwnerUserId="18774" LastEditorUserId="18774" LastEditDate="2022-03-28T15:59:44.580" LastActivityDate="2022-03-28T15:59:44.580" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23646" PostTypeId="1" AcceptedAnswerId="23651" CreationDate="2022-03-27T21:19:51.967" Score="2" ViewCount="59" Body="&lt;p&gt;It is generally believed that the time over which speciation occurs is too short (~10,000-100,000 years) for our museum collections to include many transitional forms between species. (Transitional species between groups are common, but transitional forms between species are not.)&lt;/p&gt;&#xA;&lt;p&gt;However, more fossils are being discovered over time, and if it is simply a matter of transitional forms being &lt;em&gt;relatively uncommon&lt;/em&gt;, we could imagine that at some point in the distant future it will be the rule to have them, rather than the exception.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, fossils tend to be associated with areas (like bogs) which are particularly prone to forming fossils. Bogs form in specific areas and exist for limited spans of time, and sample natural history unevenly. If the main limitation on the fossil record is the sporadic formation of fossils, rather than the sporadic discovery of those fossils, then we may never have a full account of transitional forms.&lt;/p&gt;&#xA;&lt;p&gt;Can we expect to eventually have most of the &amp;quot;missing links?&amp;quot;&lt;/p&gt;&#xA;" OwnerUserId="26608" LastActivityDate="2022-03-29T00:14:27.740" Title="Will the fossil record ever be complete enough to see inside punctuated equilibria?" Tags="|paleontology|fossils|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23647" PostTypeId="2" ParentId="23646" CreationDate="2022-03-27T22:05:18.910" Score="1" Body="&lt;p&gt;Your paragraph about fossils of land dwelling animals tending to be associated with bogs fairly well sums up the situation.&lt;/p&gt;&#xA;&lt;p&gt;Consider the contemporary situation in the remaining wilderness areas of the world. What opportunities are there for future fossils to form? It's no different to how things were thousands and millions of years ago. Some animals will die and their remains will be preserved, other animals will have their remains scattered and even destroyed by predators and other forces.&lt;/p&gt;&#xA;&lt;p&gt;As now, in the past there were a small number of locations amenable to the preservation of animal remains which resulted in fossils. Fossils examples of every life form that have existed will not be found for this reason.&lt;/p&gt;&#xA;&lt;p&gt;It's a matter of chance, which animals get fossilized. It's also a matter of chance which fossil sites get preserved and which ones get destroyed by geological forces, such as faulting, earth movements, land subduction, reburial, plate tectonics, etc. It's also a matter of chance which fossils from a fossil site are uncovered. It's also a matter of chance will fossils get identified correctly.&lt;/p&gt;&#xA;&lt;p&gt;The discovery of past life forms via fossil discovery is largely a process of serendipity. It's a scientific form of &lt;a href=&quot;https://www.wordnik.com/words/lucky%20dip&quot; rel=&quot;nofollow noreferrer&quot;&gt;lucky dip&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2022-03-27T22:26:28.660" LastActivityDate="2022-03-27T22:26:28.660" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23651" PostTypeId="2" ParentId="23646" CreationDate="2022-03-29T00:14:27.740" Score="3" Body="&lt;p&gt;the problem isn't having transitional forms, all forms are transitional, it is recognizing transitional forms, species an all but pointless definition when including time. Fossils are defined by morphology which would be the same for hundreds of related species or distinct to below the species level depending on the organism. When you include time and fossils the common definition of species is meaningless. so looking for species level change is all but impossible simply because there is no way to tell what is what we would call a species in the living population sense.&lt;/p&gt;&#xA;&lt;p&gt;That said there are fossil lake beds with millions of generations for all but continuously sampling. Lake Malawi being a famous one. What we see is neither classical punctuated equilibrium nor classical gradualism covers the sheer range of speciation events and speeds.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2022-03-29T00:14:27.740" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23652" PostTypeId="1" AcceptedAnswerId="23656" CreationDate="2022-03-29T11:18:00.823" Score="2" ViewCount="128" Body="&lt;p&gt;The &lt;a href=&quot;https://www.bbc.com/news/uk-scotland-highlands-islands-60892350&quot; rel=&quot;nofollow noreferrer&quot;&gt;BBC reported on March 28, 2022 that Guinard Island was on fire&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;That strikes me as odd. The west of Scotland should be wet in spring. A wildfire in Scotland in March seems strikingly out of place and time.&lt;/p&gt;&#xA;&lt;p&gt;A google search brought up only droughts in recent years, of which there were some.&lt;/p&gt;&#xA;&lt;p&gt;Hence the question: Did Scotland receive drastically less rain than usual in March of 2022?&lt;sup&gt;1&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;sub&gt;&lt;sup&gt;1 &lt;/sup&gt;The spring in Germany was clearly &lt;a href=&quot;https://web.de/magazine/panorama/wetter/duerre-alarm-deutschland-maerz-tropfen-geregnet-36711390&quot; rel=&quot;nofollow noreferrer&quot;&gt;much drier than usual&lt;/a&gt;, something I can attest to personally: The last significant rain must be weeks ago in Berlin. Less anecdotally, &lt;a href=&quot;https://www.rnd.de/panorama/wetter-maerz-2022-wird-wohl-der-sonnigste-seit-1951-UKHTVBCCDZE2PDGRV6AROCIOUQ.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this site&lt;/a&gt; reports that March 2022 was the sunniest and driest March on record so far: Up to March 25, there were only 1.3 mm of precipitation in what should be one of the wettest months.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="5396" LastEditorUserId="2470" LastEditDate="2022-03-29T12:18:21.263" LastActivityDate="2022-03-31T21:14:11.680" Title="Drought in Scotland?" Tags="|meteorology|precipitation|drought|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23653" PostTypeId="1" AcceptedAnswerId="23654" CreationDate="2022-03-29T20:59:53.333" Score="4" ViewCount="118" Body="&lt;p&gt;I find it bizarre that the earth rotates at &lt;strong&gt;nearly&lt;/strong&gt; 365 1/4 times per year, requiring an extra day every 4 years.&lt;/p&gt;&#xA;&lt;p&gt;I would have thought that this is just a rough estimate, but looking into leap seconds ...&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Leap_second&quot; rel=&quot;nofollow noreferrer&quot;&gt;Leap seconds&lt;/a&gt; imply that this estimate is only off by about a second per year.&lt;/p&gt;&#xA;&lt;p&gt;I would have expected it to be random, but it appears to be off by 6 hours per year.  I would have expected variation in not just the hours, but also the minutes, and in the seconds.&lt;/p&gt;&#xA;&lt;p&gt;Here is a &lt;a href=&quot;https://www.programmr.com/blogs/what-every-developer-should-know-about-leap-seconds&quot; rel=&quot;nofollow noreferrer&quot;&gt;programming perspective&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="26614" LastEditorUserId="26614" LastEditDate="2022-03-29T21:09:56.957" LastActivityDate="2022-03-31T06:01:36.663" Title="Why does the earth rotate in correlation with it's rotation around the sun to such precision?" Tags="|astronomy|time|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23654" PostTypeId="2" ParentId="23653" CreationDate="2022-03-29T21:09:33.147" Score="6" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;I find it bizarre that the earth rotates at nearly exactly 365 1/4 times per year, requiring an extra day every 4 years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The Earth does not rotate nearly exactly 365 1/4 times per year. That's the Julian calendar. The Gregorian calendar, which also is not perfect, omits leap years on years that are divisible by 100 but not by 400. The Julian calendar, with one leap year every four years, is off by about 11 minutes per year. The Gregorian calendar is off by only 27 seconds per year.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Leap seconds imply that this estimate is only off by about a second per year.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Leap seconds have nothing to do with the calendar. Leap seconds are designed to keep the 86400 atomic time seconds in sync with the Earth's rotation rate. The intent of leap seconds is to keep mean (average) solar noon in sync with observed. Leap years are a very different phenomenon; they are designed to keep the calendar in sync with the Earth's seasons.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2022-03-29T21:15:36.140" LastActivityDate="2022-03-29T21:15:36.140" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23656" PostTypeId="2" ParentId="23652" CreationDate="2022-03-30T07:51:57.377" Score="5" Body="&lt;p&gt;No there isn't a drought in Scotland, but there doesn't have to be for there to be a high fire risk.&lt;/p&gt;&#xA;&lt;p&gt;As you say, the west coast is often wet which means the conditions are ideal for the (slow) build up of peat, which is an excellent fuel when dry. The terrain is also often covered in heather (&lt;em&gt;Calluna vulgaris&lt;/em&gt;) which burns easily.&lt;/p&gt;&#xA;&lt;p&gt;It doesn't take many days of dry weather for the surface and vegetation to dry out and therefore for good wild fire conditions to build. In the northern Cairngorm National Park, which is surrounded by peat, heather and pine forest, the 'High Fire Risk' signs tend to go out after three days of no rain.&lt;/p&gt;&#xA;&lt;p&gt;At the time of the fire you refer to, Scotland was under a blocked weather pattern. There was a high pressure system over the North Sea which eventually centred over Scotland. This gave Scotland unseasonably warm weather and very dry conditions for about 10 days but not something that would be classed as a drought.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JZcrt.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JZcrt.png&quot; alt=&quot;Synoptic chart showing high pressure over UK on 27 March 2022, around the time of the fire&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I think the reason the fire made the news is two-fold:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The island was used for Anthrax testing in the past&lt;/li&gt;&#xA;&lt;li&gt;The entire island appeared to be on fire in the photos&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Overall, wild fires are not uncommon in Scotland but they usually happen later in the season. The blocking brought warm, dry weather to Scotland unseasonably early but this has now been replaced by a blast of Arctic air.&lt;/p&gt;&#xA;" OwnerUserId="20542" LastActivityDate="2022-03-30T07:51:57.377" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23657" PostTypeId="1" CreationDate="2022-03-30T17:02:37.640" Score="3" ViewCount="823" Body="&lt;p&gt;In a new video by Atlas Pro on Hawaii linked below, he indicates a curious observation: Most hotspots antipode’s have sign’s of heavy impacts from asteroids.&lt;/p&gt;&#xA;&lt;p&gt;He postulated that the force of these impacts could force magma in the earth towards the opposite side of the globe, like a magma plume but in reverse.&lt;/p&gt;&#xA;&lt;p&gt;Fundamentally, this is just a casual relationship for now, but Wegener’s ideas on plate tectonics were linked to the “jigsaw” of S.America and Africa, so this is not totally unseen in Geophysics.&lt;/p&gt;&#xA;&lt;p&gt;Hence, this leads me to ask: Has there been any serious research or papers in this idea?&lt;/p&gt;&#xA;&lt;p&gt;Link to video : &lt;a href=&quot;https://youtu.be/N7asoI4KWmE&quot; rel=&quot;nofollow noreferrer&quot;&gt;Biogeography of Hawaii Explained&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24416" LastActivityDate="2022-03-31T12:46:21.393" Title="Is there any research on the relation of asteroid impacts and hot-spots?" Tags="|plate-tectonics|hotspot|asteroids|magma-plumes|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23659" PostTypeId="2" ParentId="4876" CreationDate="2022-03-30T21:08:57.453" Score="1" Body="&lt;p&gt;Your question is partially flawed because it is not the oceans that erode continents. Instead it is the collective erosion known as denudation, the sum of all processes inclusing weathering, slope processes and fluvial processes that reduce topography on the continents.&lt;/p&gt;&#xA;&lt;p&gt;The level to which these processes tend will be the ocean level, identified as the base level. That said a few processes may erode to levels below the base level. Deep weathering could possibly reache below this level but probably only to tens of metres. Glacial processes can definitely erode to kilometers below sea level but this is localised to valleys (probably following fracture zones in the bedrock) forming fjords that may be eroded down to 1 to 1.5 km below sea level.&lt;/p&gt;&#xA;&lt;p&gt;To add to this general condition, we must consider that sea level fluctuates depending on the distribution of sea basins realtive to continents. New ocean floor is relatively high elevation when compared to older ocean floor due to density differences. Water can also be accumulated on land during cold periods which can cause sea levels to vary. Hence the sea level is far from constant through time.&lt;/p&gt;&#xA;&lt;p&gt;An implication of the question is what will happen in the future. I will assume the earths interior will cool with time chaning the continental drifting. With slowing drifting mountain building will decrease so that denudation will likely be dominating. A problem here is that we probably need to consider loss of atmosphere and other issues that we do not know much about. There are indictions from Mars that water has been more abundant in teh past yet the topography on Mars is significant because the erosional processes have lost their poser as loss of water may have been critical.&lt;/p&gt;&#xA;&lt;p&gt;So what will happen in the futiure depends on how tectonic and atmospheric processes change in the distant future due to changes or development in both the earth's interior and the atmosphere in terms of water content (water being a critical componete in both weathering of rocks abnd transport of material in topgraphic terrain).&lt;/p&gt;&#xA;&lt;p&gt;To conclude, the question is much larger than can first be thought and we need to consider large time frames in which many of existing processes and systems will drastically change. So to provide a time frame is very difficult and essentially pointless.&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2022-03-30T21:08:57.453" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23660" PostTypeId="2" ParentId="13400" CreationDate="2022-03-30T21:11:20.810" Score="0" Body="&lt;p&gt;&lt;em&gt;The fact of observable Global Warming is the evidence&lt;/em&gt; - it backs the 1896 claim by Svante Arrhenius (and others since) that raising CO2 levels by burning fossil fuels would cause global warming.&lt;/p&gt;&#xA;&lt;p&gt;It is a real world experiment that had already begun - albeit unintentionally and at small scale - in Arrhenius' time. His calculations of how much global temperature would be different with a halving or doubling of CO2 concentrations were based on 19th Century understanding of the ways different atmospheric gases pass, absorb and emit EMR - Electro Magnetic Radiation - including visible light and Infrared Radiation. That understanding of the global temperature consequences to changing the relative concentrations of atmospheric gases has gained more accuracy but otherwise unchanged.&lt;/p&gt;&#xA;&lt;p&gt;The same Greenhouse Effect featuring water vapor and CO2 answered a previous question - why Earth's surface is warmer than could be accounted for by either heat from Earth's interior or the heat of sunlight.&lt;/p&gt;&#xA;&lt;p&gt;Raising CO2 levels hasn't occurred in isolation; it has occurred within a complex weather and climate system subject to natural changes &lt;em&gt;as well as to other human environmental impacts that have climate consequences&lt;/em&gt; besides CO2. Most of the processes were more easy to identify and their fundamentals understood than it was to quantify them with sufficient accuracy to be able to predict the course of climate - which requires answers to how much each forcing has been changing, how much each has contributed and how various feedback mechanisms respond. Whilst Paleo-climate studies can reveal past climate responses from various natural causes it takes climate modeling to deal with the complex interaction and attribute the resultant changes correctly. Those effort to quantify various phenomena and interactions with sufficient accuracy have continued, but by the late 1970's onwards were enough to clearly identify CO2 rise as the largest (but by no means only) causal contributor to global climate change.&lt;/p&gt;&#xA;&lt;p&gt;What we don't have is a &lt;em&gt;control Earth&lt;/em&gt; to compare with, one where human's burned only insignificant amounts of fossil fuels and didn't cause CO2 concentrations to rise; that &lt;em&gt;all-natural&lt;/em&gt; version exists now only as modeled estimations. Welcome to the test tube.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2022-03-30T21:11:20.810" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23661" PostTypeId="1" CreationDate="2022-03-31T05:58:17.587" Score="3" ViewCount="50" Body="&lt;p&gt;How does the biological productivity of the ocean vary with depth?&lt;/p&gt;&#xA;&lt;p&gt;(By 'productivity', what I'm actually interested in is production of edible fish, but I suppose other measures like photosynthesis, probably match this to a first approximation?)&lt;/p&gt;&#xA;&lt;p&gt;In general, my understanding is that most of the ocean has low productivity because it is kilometers deep, which means the seafloor sediment (which contains the mineral nutrients) is far from the euphotic zone (which contains the sunlight); the particularly productive areas like the Grand Banks of Newfoundland, are so because they are shallow.&lt;/p&gt;&#xA;&lt;p&gt;Does that mean shallower is always better? Or is there a cutoff point of 'shallow enough'?&lt;/p&gt;&#xA;&lt;p&gt;Do currents matter? Is a shallow area that receives an upwelling current from an adjacent deep area, more productive than if it were surrounded by similarly shallow areas?&lt;/p&gt;&#xA;&lt;p&gt;What other factors am I not taking into account?&lt;/p&gt;&#xA;&lt;p&gt;What's the depth that maximizes productivity?&lt;/p&gt;&#xA;" OwnerUserId="7911" LastActivityDate="2022-03-31T05:58:17.587" Title="How does ocean productivity vary with depth?" Tags="|oceanography|water|nutrient-cycles|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23662" PostTypeId="2" ParentId="23652" CreationDate="2022-03-31T05:59:06.797" Score="2" Body="&lt;p&gt;Many small islands lack sufficient soil moisture because they have no water table, often as ecosystems ponds, puddles and rainfall and ambient humidity are only sources of water. A winter dry season of little snow or rain and all it takes to go up in flames.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2022-03-31T05:59:06.797" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23664" PostTypeId="1" CreationDate="2022-03-30T20:11:30.293" Score="2" ViewCount="117" Body="&lt;p&gt;Asking for a friend. These would probably fit better on archeology exchange, but as far as I know that kind of site does not exist yet.&lt;/p&gt;&#xA;&lt;p&gt;First specimen, friend suspects it's some kind of Proetus.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/iyDlt.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iyDlt.jpg&quot; alt=&quot;trilobite one&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Second specimen, friend suspects the genus is Asaphus.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/0Rp8Z.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0Rp8Z.jpg&quot; alt=&quot;trilobite two&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Any help in narrowing the species identification down would be appreciated.&lt;/p&gt;&#xA;" OwnerDisplayName="Puzzled" LastEditorUserId="18081" LastEditDate="2022-03-31T07:56:40.343" LastActivityDate="2022-04-02T17:59:50.513" Title="Which trilobite species are these?" Tags="|fossils|identification-request|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23665" PostTypeId="2" ParentId="23657" CreationDate="2022-03-31T12:46:21.393" Score="2" Body="&lt;p&gt;This question has been researched for decades. Here are two examples of such studies (you can find more by looking at articles citing those two).&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;In &lt;a href=&quot;https://doi.org/10.1006/icar.1994.1116&quot; rel=&quot;nofollow noreferrer&quot;&gt;Assessment of Antipodal-Impact Terrains on Mars&lt;/a&gt;, Williams &amp;amp; Greeley (1994) ran impact-related energy models, suggesting that:&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;antipodal pressures from the Hellas impact probably produced&#xA;sufficient focused energy at its antipode to produce deep fractures&#xA;(on the order of tens of kilometers) in the Martian crust centered&#xA;below the current caldera for Alba Patera, and may account for aspects&#xA;of volcanism at Alba.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;In &lt;a href=&quot;https://doi.org/10.1130/0-8137-2307-8.541&quot; rel=&quot;nofollow noreferrer&quot;&gt;Axial focusing of impact energy in the Earth's interior: A possible link to flood basalts and hotspots&lt;/a&gt;, Boslough et al. (1996) ran seismological simulations, showing that:&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;displacement&#xA;and strain amplitudes at the surface of the Earth near the&#xA;antipode of a large impact are an order of magnitude larger than&#xA;those over most of the rest of the Earth’s surface and that the&#xA;seismic energy remains sharply focused down to the core-mantle boundary. These simulations provide the proof-of-principle&#xA;basis supporting the hypothesis that large impacts on Earth can&#xA;generate effects deep in the mantle that might lead to observable consequences.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Note that asteroids impacts have not been associated to antipodal volcanism only. They can also trigger &amp;quot;plume-like&amp;quot;, decompression melting at the impact site. In &lt;a href=&quot;https://doi.org/10.1016/S0012-821X(02)00824-5&quot; rel=&quot;nofollow noreferrer&quot;&gt;Impact induced melting and the development of large igneous provinces&lt;/a&gt;, Jones et al. (2002) made the hypothesis that the Siberian Traps could be the result of a large impact. Volcanism triggered by such impacts would fill the craters, explaining their absence on Earth.&lt;/p&gt;&#xA;&lt;p&gt;Yet another study, &lt;a href=&quot;https://doi.org/10.1016/S0012-821X(02)01013-0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Extraterrestrial influences on mantle plume activity&lt;/a&gt; (Abbott &amp;amp; Isley 2002), postulates that large impacts strengthen existing plumes (not necessarily at the antipodal point). This is illustrated by the fact that the Deccan traps, which were already active before the Chixculub impact, had their most voluminous phase of volcanism immediately after the impact.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2022-03-31T12:46:21.393" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23666" PostTypeId="1" CreationDate="2022-03-31T14:45:55.627" Score="4" ViewCount="2010" Body="&lt;p&gt;Concrete is the key ingredient to building housing, roads, and all kinds of infrastructure. Curing of concrete makes sure that the infra is rock solid and reliably durable and safe. But, it also consumes humongous amounts of water irreversibly, and this water is not returning to the ecosystem of water cycle.&lt;/p&gt;&#xA;&lt;p&gt;Till how many years can we carry this on until the situation becomes grave?&lt;/p&gt;&#xA;" OwnerUserId="22476" LastActivityDate="2022-05-31T15:15:56.547" Title="How do we compensate the water that is being taken out of water cycle for curing of concrete in infra construction?" Tags="|water|water-table|urban-climate|" AnswerCount="4" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23667" PostTypeId="2" ParentId="23666" CreationDate="2022-03-31T15:23:07.603" Score="1" Body="&lt;p&gt;Global sea level rise is an increasing problem that governments are struggling to find a solution to. Sea level rise is mostly caused by ice sheets, and other permanent snow/ice, melting and a little by expansion of the sea due to higher temperatures. If sea level rise could be mitigated by use of concrete I assume this would have been mentioned in the IPCC reports. Overall I cannot imagine that what you suggest is a serious problem or likely to become one.&lt;/p&gt;&#xA;" OwnerUserId="20542" LastActivityDate="2022-03-31T15:23:07.603" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23668" PostTypeId="2" ParentId="23666" CreationDate="2022-03-31T17:55:27.793" Score="10" Body="&lt;p&gt;The top twelve cement producing countries &lt;a href=&quot;https://www.statista.com/statistics/267364/world-cement-production-by-country/&quot; rel=&quot;noreferrer&quot;&gt;in 2020&lt;/a&gt; produced 3191 Mt of cement. Increase this to 4000 Mt to include the rest of the world.&lt;/p&gt;&#xA;&lt;p&gt;Depending on the application, the &lt;a href=&quot;https://civiconcepts.com/blog/water-cement-ratio&quot; rel=&quot;noreferrer&quot;&gt;water to cement ratio of concrete&lt;/a&gt; is between 0.4 and 0.6.&lt;/p&gt;&#xA;&lt;p&gt;Assuming the worst case scenario of 0.6, then 2400 Mt of water was locked in concrete in 2020.&lt;/p&gt;&#xA;&lt;p&gt;Now, 1 t of water occupies 1 m&lt;sup&gt;3&lt;/sup&gt;, which is the same a 1000 L (1 kL). This means 2400 million cubic meters of water (2.4(10)&lt;sup&gt;12&lt;/sup&gt; L, or 2.4 TL, or 2400 GL) was locked in concrete in 2020.&lt;/p&gt;&#xA;&lt;p&gt;Another way of looking at it is, 2400 million cubic meters is 2.4 km&lt;sup&gt;3&lt;/sup&gt;, which is a minuscule fraction of the total &lt;a href=&quot;https://ngdc.noaa.gov/mgg/global/etopo1_ocean_volumes.html&quot; rel=&quot;noreferrer&quot;&gt;volume of the worlds oceans&lt;/a&gt;, which is 1,335,000,000 km&lt;sup&gt;3&lt;/sup&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-03-31T17:55:27.793" CommentCount="16" ContentLicense="CC BY-SA 4.0" />
  <row Id="23669" PostTypeId="2" ParentId="23652" CreationDate="2022-03-31T21:14:11.680" Score="3" Body="&lt;p&gt;The West of Scotland is in general much wetter than most of the rest of Britain. The principal cause is orographic rain associated with the westerly winds from the Atlantic ocean that deposit water in the West as they rise over the mountains. However, it is often the case in spring that Scotland enjoys cool damp easterlies that lose moisture on the east side of the mountains, leading to noticeably clearer dry conditions in the west. I lived in Oban for quarter of a century and am well familiar with this pattern.&lt;/p&gt;&#xA;" OwnerUserId="1025" LastActivityDate="2022-03-31T21:14:11.680" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23670" PostTypeId="1" CreationDate="2022-04-01T23:43:16.237" Score="3" ViewCount="41" Body="&lt;p&gt;This seems like a simple question, but I can't find much information on the web about this, and I haven't studied Geology or Geophysics.&lt;/p&gt;&#xA;&lt;p&gt;In Valparaíso there are a large number of &amp;quot;Cerros&amp;quot; (&amp;quot;= hills&amp;quot; - some locals say 42) around the bay, and they are really steep. From sea level, they rise to around 200m within around 300 or 400m from the &amp;quot;plan&amp;quot; (an area recovered from the sea where most of the city centre is). These hills all rise from the coast quite rapidly, and outside of Valparaiso, towards Santiago, the average elevation drops a little and then rises as it meets the pre-cordillera of the Andes at about 1000-1800m.&lt;/p&gt;&#xA;&lt;p&gt;The sudden rise is so steep that there are several funicular railways that serve the local population to help them get up the first 60-100m or so. There are even staircases next to them which few people use unless they are walking down!&lt;/p&gt;&#xA;&lt;p&gt;Valparaíso is part of the Pacific &amp;quot;Rim of Fire&amp;quot;, and there is the Pacific subduction zone quite close offshore.&lt;/p&gt;&#xA;&lt;p&gt;So would all these hills be formed by repeated uplift due to earthquakes, which are weathered down over time? There are no cliffs to speak of in the area, just a lot of hills.&lt;/p&gt;&#xA;&lt;p&gt;Or would glacial processes have been involved? When the Andes was formed, I imagine the glaciers would have made their way toward the sea and dump loads of material near the coast which might have formed these hills?&lt;/p&gt;&#xA;&lt;p&gt;Could someone help me with the answers, or point me towards scientific information about the Geological history of the area?&lt;/p&gt;&#xA;&lt;p&gt;Many thanks,&lt;/p&gt;&#xA;&lt;p&gt;-Blue&lt;/p&gt;&#xA;" OwnerUserId="26629" LastActivityDate="2022-04-01T23:43:16.237" Title="Coastal Hill Formation (Valparaíso, Chile)" Tags="|geology|coastal|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23671" PostTypeId="1" AcceptedAnswerId="23678" CreationDate="2022-04-02T06:18:58.557" Score="5" ViewCount="156" Body="&lt;p&gt;I've been learning about seismic discontinuities, mainly the 5 defined ones - Conorod discontinuity, Mohorovicic discontinuity, Repetti discontinuity, Gutenberg discontinuity, and Lehmann discontinuity. But I cannot find a discontinuity along the lithosphere-asthenosphere boundary. As far as I know, the asthenosphere is 1% molten rock, which means seismic waves travel relatively slower through it. Then why isn't there a discontinuity between the lithosphere and asthenosphere?&lt;/p&gt;&#xA;" OwnerUserId="22020" LastActivityDate="2022-04-04T01:39:32.620" Title="Is there a seismic discontinuity between the lithosphere and asthenosphere?" Tags="|earthquakes|seismic|crust|mantle|lithosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23673" PostTypeId="2" ParentId="23664" CreationDate="2022-04-02T17:59:50.513" Score="5" Body="&lt;p&gt;The first specimen seems more like &lt;em&gt;Elrathia&lt;/em&gt; sp.  Features noted that were similar are small eyes, small projecting genal spine (extreme left and right at the posterior margin of the cephalon), and strong anterior taper of the glabella (crown, or dome, between the eyes, tapers toward the nose).  The pleural lobe (tail segment) is ovate along a lateral left-right axis and has few furrows. The specimen shows typical flattening (crushing) caused by the weight of the overburden during burial and lithification.&lt;/p&gt;&#xA;&lt;p&gt;Although &lt;em&gt;Proetus&lt;/em&gt; sp. shows features like &lt;em&gt;Elrathia&lt;/em&gt;, the genal spines do not project as those in &lt;em&gt;Elrathia&lt;/em&gt;. The glabella in &lt;em&gt;Proetus&lt;/em&gt; is not strongly tapered, and the plural lobe, which has many furrows, is more elongated along the length of the shell rather than left to right.&lt;/p&gt;&#xA;&lt;p&gt;The second specimen is harder to identify, but is similar in several aspects to &lt;em&gt;Phacops&lt;/em&gt; sp, having pronounced eye-buds, and textured glabella.  The specimen obviously appears small, perhaps a juvenile.  An adult would be about 8.5 cm in length.  This specimen is uncrushed.&lt;/p&gt;&#xA;&lt;p&gt;Trilobites are called that because they have three lobes, namely, cephalon (head), thorax (central body), and pygidium (truncated posterior lobe).  The animals molted regularly, so a single animal could produce a considerable number of shells over its lifetime.  The fossilized remnants of the living animal, at death, are rarely if ever found.  Trilobites had two shells, a dorsal shell, which is usually found, and a much softer ventral shell.  This ventral shell, and the soft tissues of the trilobite animal, usually deteriorated after death so little is known about what trilobites looked like in life.&lt;/p&gt;&#xA;&lt;p&gt;The following reference was consulted -&lt;/p&gt;&#xA;&lt;p&gt;Easton, W. H., 1960, &lt;em&gt;Invertebrate Paleontology,&lt;/em&gt; Harper and Row, New York.&lt;/p&gt;&#xA;" OwnerUserId="26632" LastActivityDate="2022-04-02T17:59:50.513" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23674" PostTypeId="1" AcceptedAnswerId="23676" CreationDate="2022-04-03T04:44:47.577" Score="1" ViewCount="74" Body="&lt;p&gt;I an working on a Si-Fi world, and am looking for ways that an area would, over a long timescale, lose the majority of its water. I understand how the lose of vegetative cover due to climate changes and overgrazing can lead towards desertification, but how does the dryness come about, and if you can answer it, how can I justify this on a more planetary scale?&lt;/p&gt;&#xA;&lt;p&gt;I am also not looking for human-caused changes, but things that naturally came about.&lt;/p&gt;&#xA;&lt;p&gt;Assume an Earth-like climate before the change.&lt;/p&gt;&#xA;" OwnerUserId="26118" LastActivityDate="2022-04-03T19:35:23.727" Title="What are some reasons for Aridification" Tags="|climate-change|water|climate-models|humidity|desertification|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23676" PostTypeId="2" ParentId="23674" CreationDate="2022-04-03T18:19:07.300" Score="0" Body="&lt;p&gt;The major reason for aridification is the decline and eventual loss of rainfall. The reasons for this are numerous:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Plate tectonics&lt;/strong&gt; - continents moving from one location to another. An example of this is Australia. It was once attached to Antarctica. It was also lot lusher than it is today, but as it slowly moved northwards it moved into latitudes which had less rain and dried out.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Orogeny&lt;/strong&gt; - which is the formation of mountains, particularly on the western side of continents, interrupts the flow of moist air from oceans over continents. In moving over the mountain ranges the air must rise resulting in rain zones on the oceanic side of the mountain ranges and rain shadow regions on the other side of the mountain ranges, The other result of this is the drying out of land on the rain shadow side of the mountain ranges. Examples of this are the &lt;a href=&quot;https://en.wikipedia.org/wiki/Patagonian_Desert&quot; rel=&quot;nofollow noreferrer&quot;&gt;Patagonian Desert&lt;/a&gt;, in Argentina, and the deserts of North America.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;&lt;em&gt;Excessive&lt;/em&gt; volcanic activity&lt;/strong&gt; can lead to volcanoes emitting excessive amounts of carbon dioxide, which along with other events can tip the balance regarding global warming. Likewise, &lt;strong&gt;&lt;em&gt;excessive&lt;/em&gt; volcanic inactivity&lt;/strong&gt; can lead to an excessive decline in atmospheric carbon dioxide which would lead to global cooling and a loss of rainfall in some regions.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Changes in Ocean Currents&lt;/strong&gt; - can also cause aridification. The changes can be changes in direction which can result in the movement of either warm or cold ocean water which disrupts what was previously there. If the &lt;a href=&quot;https://en.wikipedia.org/wiki/Gulf_Stream&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gulf Stream&lt;/a&gt;  were to collapse one of the results would be a significant change in the rainfall patterns over Europe. This would be an example of a &lt;a href=&quot;https://en.wikipedia.org/wiki/Shutdown_of_thermohaline_circulation&quot; rel=&quot;nofollow noreferrer&quot;&gt;shutdown of thermohaline circulation&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Prolonged changes in &lt;a href=&quot;https://oceanservice.noaa.gov/facts/ninonina.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;El Niño&lt;/a&gt; and &lt;a href=&quot;http://www.bom.gov.au/climate/enso/history/ln-2010-12/ENSO-what.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;La Niña&lt;/a&gt; events&lt;/strong&gt; in the Pacific Ocean can seriously disrupt rainfall creating either too much or too little rain various regions. The Indian Ocean has a similar system called the &lt;a href=&quot;http://www.bom.gov.au/climate/enso/history/ln-2010-12/IOD-what.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Indian Ocean Dipole&lt;/a&gt;. All this can have serious implications for east Africa, southern Asia, Australia and North and South America.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;&lt;a href=&quot;https://www.encyclopedie-environnement.org/en/zoom/land-salinization/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Land salinization&lt;/a&gt;&lt;/strong&gt; occurs when salt from below the surface of the Earth is brought to the surface by excessive land clearing for agriculture and the water rises bringing with the subterranean salt, as has happened in many parts or the world that have cleared land for agriculture. The other cause of land salinization is the over use of irrigation for agriculture, as occurred in &lt;a href=&quot;https://en.wikipedia.org/wiki/Mesopotamia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mesopotamia&lt;/a&gt;. All agricultural &amp;quot;fresh&amp;quot; water contains small amounts of salt which accumulates in soil over time. Land salinization results in the loss of vegetation and land cover. Large areas of land salinization have resulted in desertification and aridification of regions.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2022-04-03T18:27:23.340" LastActivityDate="2022-04-03T18:27:23.340" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23677" PostTypeId="2" ParentId="23674" CreationDate="2022-04-03T19:35:23.727" Score="0" Body="&lt;h2&gt;Glaciation&lt;/h2&gt;&#xA;&lt;p&gt;causes short-term (several thousand to a few million years) changes in rainfall in various regions on the Earth.&lt;/p&gt;&#xA;&lt;p&gt;Regions that are normally dry can go through a &amp;quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Pluvial&quot; rel=&quot;nofollow noreferrer&quot;&gt;pluvial&lt;/a&gt; period&amp;quot;, that is, one of increased rainfall, in which they green up. When the ice retreats, the rain goes away and these areas become dry again.  The Sahara and the western US are great examples.&lt;/p&gt;&#xA;&lt;p&gt;Similarly, areas that are wet in a warm period can become dry during an ice age.&lt;/p&gt;&#xA;&lt;p&gt;Glaciation also causes a sea level drop, ans subsequent changes from meltwater and isostasy, and this makes ocean currents and littoral climate zones move around.&lt;/p&gt;&#xA;&lt;p&gt;Finally, the ice sheets themselves can be as rainless as Antarctica,  which has sometimes been called &amp;quot;the biggest and dryest desert on Earth&amp;quot;. The Dry Valleys of Antarctica are the dryest ice-free areas on the planet.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastActivityDate="2022-04-03T19:35:23.727" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23678" PostTypeId="2" ParentId="23671" CreationDate="2022-04-03T22:57:36.730" Score="3" Body="&lt;p&gt;&lt;strong&gt;Short answer&lt;/strong&gt;: There are actually &lt;strong&gt;two&lt;/strong&gt; different Gutenberg discontinuities, and one of them corresponds to one way of defining the &lt;a href=&quot;https://en.wikipedia.org/wiki/Lithosphere%E2%80%93asthenosphere_boundary&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lithosphere-asthenosphere boundary&lt;/a&gt;, or LAB.&lt;/p&gt;&#xA;&lt;p&gt;(The abstract of &lt;a href=&quot;https://www.science.org/doi/10.1126/science.1215433&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article in Science&lt;/a&gt; refers to the LAB version of the Gutenberg discontinuity as G.)&lt;/p&gt;&#xA;&lt;p&gt;The boundary between the lithosphere and asthenosphere can be defined in several ways: mechanically, thermally, rheologically, compositionally, and finally seismically. All are approximations for something humans will never be able to access directly.&lt;/p&gt;&#xA;&lt;p&gt;Wikipedia has this to say about the seismic definition:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The seismic LAB (i.e. measured using seismological observations) is defined by the observation that there exists seismically fast lithosphere (or a lithospheric lid) above a low-velocity zone (LVZ).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The seismic LVZ was first recognized by &lt;a href=&quot;https://en.wikipedia.org/wiki/Beno_Gutenberg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Beno Gutenberg&lt;/a&gt;, &lt;em&gt;&lt;strong&gt;whose name is sometimes used to refer to the base of the seismic LAB beneath oceanic lithosphere&lt;/strong&gt;&lt;/em&gt;. The Gutenberg discontinuity coincides with the expected LAB depth in many studies and has also been found to become deeper under older crust, thus supporting the suggestion that the discontinuity is closely interrelated to the LAB.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2022-04-04T01:39:32.620" LastActivityDate="2022-04-04T01:39:32.620" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23679" PostTypeId="1" CreationDate="2022-04-04T05:00:38.807" Score="3" ViewCount="107" Body="&lt;p&gt;It would be good to have satellites that gave current readings of skin temperature so that farmers could see if their crop was freezing or too hot, as well as for other global warming monitoring. Would this be possible, why isn't there one?&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="2470" LastEditDate="2022-04-04T05:38:49.383" LastActivityDate="2022-04-05T21:44:37.673" Title="Skin temperature, live update satellites, are there any? If not, why not?" Tags="|temperature|satellites|" AnswerCount="2" CommentCount="13" ContentLicense="CC BY-SA 4.0" />
  <row Id="23680" PostTypeId="1" CreationDate="2022-04-04T11:56:49.117" Score="2" ViewCount="46" Body="&lt;p&gt;The US and EU have very different government funding systems for weather and space equipment, perhaps as different as the road systems. The US has a higher performing health system on average at a higher price, what about the weather, how does the EU and US compare in that field? What areas of weather prediction and measurement do both regions perform best, and what is different about the commercialization?&lt;/p&gt;&#xA;" OwnerUserId="3315" LastActivityDate="2022-04-04T11:56:49.117" Title="US vs EU weather systems commercialization and precision?" Tags="|meteorology|numerical-modelling|satellites|" AnswerCount="0" CommentCount="5" ClosedDate="2022-04-05T08:08:42.720" ContentLicense="CC BY-SA 4.0" />
  <row Id="23682" PostTypeId="1" CreationDate="2022-04-05T00:34:36.653" Score="3" ViewCount="53" Body="&lt;p&gt;In this typical image of rock fracturing, why do the joints / fissures occur where they do, as opposed to, say, along the line drawn in blue on the image?  More specifically, what characteristics of the rock grains on the separated joint surfaces result in a (relatively) planar joint surface?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DkLTw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DkLTw.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11172" LastEditorUserId="2958" LastEditDate="2022-11-21T17:20:55.117" LastActivityDate="2022-11-21T17:20:55.117" Title="Why does fracturing occur along a specific plane or region of the rock?" Tags="|rocks|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23683" PostTypeId="1" CreationDate="2022-04-05T04:21:52.963" Score="4" ViewCount="134" Body="&lt;p&gt;I'm trying to find and use data involving total cloud cover %. I have downloaded data from NCEI/NOAA specifically &lt;a href=&quot;https://www.ncei.noaa.gov/data/global-forecast-system/access/grid-003-1.0-degree/forecast/202204/20220402/gfs_3_20220402_0000_000.grb2&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; and I'm plotting it like this:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import xarray as xr&#xA;import numpy as np&#xA;import matplotlib.pyplot as plt&#xA;import pygrib&#xA;import cartopy.crs as ccrs&#xA;import cartopy.feature as cfeature&#xA;&#xA;#loading dataset ForecastTestDate.grb2&#xA;#filtering by atmosphereSingleLayer level&#xA;ds=xr.open_dataset('gfs_3_20220402_0000_000.grb2', engine='cfgrib', filter_by_keys={'stepType': 'instant', 'typeOfLevel': 'atmosphere'})&#xA;#showing level info&#xA;ds&#xA;&#xA;#tcc is one of the data variables for atmosphere&#xA;#tcc = total cloud cover&#xA;fig,ax=plt.subplots()&#xA;im=ax.imshow(ds.tcc)&#xA;fig.colorbar(im, orientation='vertical')&#xA;plt.show()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;I get this plot:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/tKqvH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tKqvH.png&quot; alt=&quot;map of world showing cloud cover&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Obviously this is a lot of cloud and it is a lot more than is shown on zoom earth for the same day. I assume that that the total cloud cover % is inverted? Is this common practice and/or will it be the same for the other datasets from the same database?&lt;/p&gt;&#xA;" OwnerUserId="26641" LastActivityDate="2022-04-06T09:04:33.270" Title="Total Cloud Cover% from NOAA inverted?" Tags="|meteorology|clouds|open-data|weather-satellites|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23685" PostTypeId="2" ParentId="23666" CreationDate="2022-04-05T07:42:18.637" Score="2" Body="&lt;p&gt;Concrete loses some minute water over time. It's undergoing curing....however for most part, Concrete does not harden by evaporation, it hardens by a chemical process called hydration. The water added to concrete mix becomes a part of the concrete and never leaves concrete or evaporates,in essence becoming a new substance.&lt;br /&gt;&#xA;As a whole average water use is 82.8 liters per ton, with 365 billion liters used yearly...&#xA;According to researchers, Global concrete production and totals since 1900, Humanity has produced 549 Gigatons (billion) of Concrete, using 12 TRILLION gallons of water.&#xA;Oceans water mass is 1.4 × 10^21 kg or 1.4 Quintillion tonnes. Human concrete use in a Century used 1/2,500,000th of the Earths water.&#xA;Comparison: If you have a 1 gallon jug of water representing ALL water on Earth, You've used ONE drop.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2022-04-05T07:42:18.637" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23686" PostTypeId="2" ParentId="23679" CreationDate="2022-04-05T08:18:07.370" Score="4" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;It would be good to have satellites that gave current readings of skin temperature so that farmers could see if their crop was freezing or too hot&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is not generally possible in near real time (&amp;quot;live update&amp;quot;), but satellites may still offer some useful information.  There are several problems:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Satellites can measure skin temperature using infrared sensors only in the absence of clouds.  On average, 67% of Earth and 55% of land is covered in clouds (King et. al, 2013)  (of course, this number various strongly with time and place).  Therefore, much or most of the time, satellites cannot measure skin temperature instantly, but have to wait for a cloud-free moment.  However, dry nights (no cloud and not much water vapour) cool down more than humid or cloudy nights, so maybe during the most at-risk nights the radiometres can still give a clue.&lt;/li&gt;&#xA;&lt;li&gt;To monitor in near-real time, you need to use either geostationary satellites or a very large swarm of low Earth Orbit satellites.&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The spatial resolution of infrared channels in geostationary satellites is too poor.  Most geostationary imagers have resolutions of more than a kilometre.  The current Meteosat generation has 3×3 km² at sub satellite point and closer to 4×6 km² in central Europe.&lt;/li&gt;&#xA;&lt;li&gt;A very large swarm would be costly, and the infrared resolution would still be dozens of metres.&lt;/li&gt;&#xA;&lt;li&gt;High resolution imagers in any case only regard a small area at any time.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;In theory, microwave can be used to measure surface temperature in the presence of clouds (although for a thicker layer than infrared), but only with a good knowledge of surface emissivity (which is a function of soil moisture, among other things), and the spatial resolution of microwave sensors is much worse (&amp;gt;10 km from low earth orbit, non-existent from geostationary orbit).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;A resolution of 1×1 km² from geostationary orbit would already be very ambitious, where 2×2 km² or more is more realistic.  I'm not sure if this is good enough for farmers for discriminating the skin temperature of their crops from the skin temperature of the general area, which may be quite different (heat loss in a clear night strongly depends on surface material).&lt;/p&gt;&#xA;&lt;p&gt;Farmers who wish to monitor their crop temperature in real time should probably just use infrared cameras installed at their property or possibly with drones constantly flying in the air.  Whether this is cost-effective is beyond the scope of Earth Science SE.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;as well as for other global warming monitoring&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is routinely done, but this does not need a high spatial resolution and it does not need to be in near real time.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;M. D. King, S. Platnick, W. P. Menzel, S. A. Ackerman and P. A. Hubanks, &amp;quot;Spatial and Temporal Distribution of Clouds Observed by MODIS Onboard the Terra and Aqua Satellites,&amp;quot; in IEEE Transactions on Geoscience and Remote Sensing, vol. 51, no. 7, pp. 3826-3852, July 2013, doi: 10.1109/TGRS.2012.2227333. &lt;a href=&quot;https://ieeexplore.ieee.org/document/6422379&quot; rel=&quot;nofollow noreferrer&quot;&gt;Accessed online 5 April 2022&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2022-04-05T19:55:07.053" LastActivityDate="2022-04-05T19:55:07.053" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="23687" PostTypeId="2" ParentId="23683" CreationDate="2022-04-05T12:26:32.593" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;I assume that that the total cloud cover % is inverted?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;No, it's not. As gerrit mentioned in a comment, about 70% of the Earth is covered by clouds at any point in time. Science fiction movies and TV shows up to the mid 1960s showed a cloud-free Earth. Science fiction movies and TV shows since then have tended to show a much more realistic image of the Earth, which is mostly covered by clouds. It was the onset of the satellite era that made those sci-fi movies change.&lt;/p&gt;&#xA;&lt;p&gt;To make matters worse, your generated image appears to be using an equirectangular projection. It appears you have 0 as the north pole and 180 as the south pole (so co-latitude rather than latitude), with equal steps in co-latitude equally spaced on your generated image. This kind of projection exaggerates areas at high latitudes. High latitude regions are much more likely to be cloudy than are equatorial regions.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-04-05T12:26:32.593" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23688" PostTypeId="2" ParentId="23679" CreationDate="2022-04-05T14:32:19.840" Score="2" Body="&lt;p&gt;Not, because the costs of satellite image provider are excessive, and the same idea can be exploited with drones (and in fact it is being commercially exploited, as it can be seen by accessing this report &lt;a href=&quot;https://www.businessinsider.com/agricultural-drones-precision-mapping-spraying?r=US&amp;amp;IR=T&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.businessinsider.com/agricultural-drones-precision-mapping-spraying?r=US&amp;amp;IR=T&lt;/a&gt; ).&lt;/p&gt;&#xA;&lt;p&gt;I suggest to have a look at this study:&#xA;&lt;a href=&quot;https://www.researchgate.net/publication/341253627_Applications_of_UAV_Thermal_Imagery_in_Precision_Agriculture_State_of_the_Art_and_Future_Research_Outlook&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/publication/341253627_Applications_of_UAV_Thermal_Imagery_in_Precision_Agriculture_State_of_the_Art_and_Future_Research_Outlook&lt;/a&gt;&#xA;to understand where we are in 2022 in terms of implementation of remote sensing and precision agriculture (we are quite ahead wrt to what OP question implies).&lt;/p&gt;&#xA;" OwnerUserId="5887" LastEditorUserId="5887" LastEditDate="2022-04-05T21:44:37.673" LastActivityDate="2022-04-05T21:44:37.673" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23689" PostTypeId="1" CreationDate="2022-04-05T21:43:54.217" Score="7" ViewCount="292" Body="&lt;p&gt;There has been a lot discussed about historical and future global temperature increases of a few degrees (e.g. the goal of limiting the rise this century to 1.5 °C or 2 °C). Intuitively, I'm tempted to think about this in terms of my local temperature consistently being a couple degrees warmer, which doesn't seem that significant. After all, the temperature can change by much more than 2 degrees from day to day, or even within a few hours, so having highs of 12 °C today and 17 °C tomorrow doesn't seem like a big deal compared to 10 °C today and 15 °C tomorrow.&lt;/p&gt;&#xA;&lt;p&gt;How do I understand why this comparison is wrong and how a few degrees of change translates to the dramatic impact that seems to be predicted by climate scientists?&lt;/p&gt;&#xA;&lt;p&gt;I suspect one factor is that the global temperature increases being talked about are not actually uniform at all; some places might heat up more than others, and the effect might be concentrated in smaller time periods (so a particular place might end up 10 °C hotter in the summer, for example).&lt;/p&gt;&#xA;&lt;p&gt;I'm also guessing that there could be areas in a delicate equilibrium for which a small change in the average local temperature would have major effects. For example, ice would tend to stay frozen or accumulate in a location with a -1 °C average, but it would tend to melt if the average increased to 1 °C.&lt;/p&gt;&#xA;&lt;p&gt;Are these guesses correct? If so, what research or other resources are there to back them up and explain in more detail? What are some other specific repercussions I might not be aware of?&lt;/p&gt;&#xA;" OwnerUserId="26646" LastEditorUserId="2470" LastEditDate="2022-04-06T18:01:38.617" LastActivityDate="2022-04-17T23:50:04.613" Title="Why is my intuition wrong about the significance of a few degrees' temperature rise?" Tags="|climate-change|temperature|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23690" PostTypeId="2" ParentId="23683" CreationDate="2022-04-06T09:04:33.270" Score="2" Body="&lt;p&gt;I wasn't as quick to be convinced, but looks like this GFS model plot of simulated IR satellite over the previous hour for 1Z on the 2nd (so basically the same time as your image) verifies it's not inverted.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UPSqq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UPSqq.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;From &lt;a href=&quot;https://www.tropicaltidbits.com/analysis/models/?model=gfs&amp;amp;region=global&amp;amp;pkg=ir&amp;amp;runtime=2022040200&amp;amp;fh=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;TropicalTidbits.com&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Specifically this feature trailing over the Pacific and east Asia:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/TNwDb.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TNwDb.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I'm surprised its that cloudy on Earth.  The one thing that does stand out about your image is almost all cloudy regions are at 100%... which would seem to contrast with the amount of times with partial cloudcover.  So I'm not sure on that quite.  Though when you throw in fog, stratus, marine layers, convective precip, etc... I suppose its feasible.  Or perhaps a factor of data or plot resolution???&lt;/p&gt;&#xA;&lt;p&gt;It seemed worthwhile to me to take a look at the &lt;a href=&quot;https://weather.cod.edu/satrad/?parms=global-fulldiskeast-07-24-1-100-1&amp;amp;checked=map&amp;amp;colorbar=undefined&quot; rel=&quot;nofollow noreferrer&quot;&gt;GOES full disk with cloud top phase turned on&lt;/a&gt; to emphasize the different clouds to get a better idea how things really are in the full spectrum of clouds.  Do hope you get it sorted, but does seem you might actually be more where you want to be than you thought.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2022-04-06T09:04:33.270" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23691" PostTypeId="2" ParentId="23689" CreationDate="2022-04-06T13:51:24.227" Score="7" Body="&lt;p&gt;One place where your intuition is failing you is that if the Earth warms up by 2°C on average, that will be averaged over the surface of the Earth. The Earth's surface is covered mostly by water (71%). Due to the much greater heat capacity of water versus land, the warming will mostly be over land. To make the warming be 2°C averaged over the surface of the Earth, the Earth's land surface will be warmed significantly more than 2°C. Most humans live on land.&lt;/p&gt;&#xA;&lt;p&gt;Another place where your intuition is failing you is that you are confusing climate and weather. Weather is chaotic and highly variable. It is not at all unusual to experience a day where the temperature is 10°C higher or lower than nominal. The effect of a 4°C warming over land will result in significant portions of the Earth becoming uninhabitable due to extreme summertime heatwaves. This will not be cool (pun intended).&lt;/p&gt;&#xA;&lt;p&gt;Yet another place where your intuition is failing you is that the warming over Greenland and Antarctica will result in significant sea level rise. The polar regions are where warming is most severe -- and most sensitive. While hardly any humans live on Greenland or Antarctica, a huge chunk of humanity lives close to an ocean shore. The warming over Greenland and Antarctica represents a threat to all humans who live close to an ocean shore.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-04-06T13:51:24.227" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23692" PostTypeId="2" ParentId="23689" CreationDate="2022-04-06T17:23:33.267" Score="5" Body="&lt;p&gt;Aside from David's answer, another aspect of global warming is the change in temperature gradients and their impact on ecologies. This map will give you a sense of what parts of the United States freeze first; those dates are gradually shifting later in the year and spring temperatures are coming sooner. That's important for a couple of reasons: Freezes kill nuisance insects (and some crops), and crops are affected by the amount of heat units they're exposed to during their growing season.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/mjus7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mjus7.png&quot; alt=&quot;Climatological Date of Median First 32°F freeze for the United States. &quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;For example, certain plants and insects thrive best in a given temperature range; as temperatures rise, that range tends to get shifted toward the poles. There are insect populations that remain under control because they or their brood die off in the winter because temperatures drop to or below freezing. Warming will shift that freezing line poleward, and also helps some supporting plants that were not common to spread; those insects will become a pest in a region that's not used to them. See &lt;a href=&quot;https://www.sciencedaily.com/releases/2018/05/180517113751.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate change broadens threat of emerald ash borer&lt;/a&gt; or &lt;a href=&quot;http://nora.nerc.ac.uk/id/eprint/8332/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nuisance insects and climate change&lt;/a&gt;. (For sea life, we do see a general poleward movement; you can have a fish species that see their optimal water temperature shift by tens of miles, pushing them away from where locations where they've evolved to feed or reproduce.)&lt;/p&gt;&#xA;&lt;p&gt;In terms of the impact on crops, here's &lt;a href=&quot;https://e360.yale.edu/features/spurred_by_warming_climate_beetles_threaten_coffee_crops&quot; rel=&quot;nofollow noreferrer&quot;&gt;a specific example from Yale360 about coffee production&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Arabica coffee grown in Ethiopia and Latin America is an&#xA;especially climate-sensitive crop. It requires just the right amount&#xA;of rain and an average annual temperature &lt;strong&gt;between 64 degrees&#xA;Fahrenheit and 70 degrees Fahrenheit&lt;/strong&gt; to prosper. As temperatures rise&#xA;— Ethiopia’s average low temperature has increased by about .66&#xA;degrees F every decade since 1951, according to the country’s National&#xA;Meteorological Agency — and rains become more variable, Ethiopian&#xA;coffee farmers have suffered increasingly poor yields.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So you can see how a slight but continuing gradient shift will alter entire ecosystems and the relationships between insects and plants. In the long term ecosystems can and do adjust to changing climates, but our agriculture and supporting infrastructure is largely optimized for last century's conditions.&lt;/p&gt;&#xA;&lt;p&gt;I was also reminded today of the cold snap that hit the United States in February 2021 and the possibility that it was due to increased wandering of the polar vortex. &lt;a href=&quot;https://www.climate.gov/news-features/understanding-climate/understanding-arctic-polar-vortex&quot; rel=&quot;nofollow noreferrer&quot;&gt;This band of winds that surrounds the North Pole at altitude in the winter holds in a pool of cold air.&lt;/a&gt; Polar winds largely exist because of the differential between polar temperatures and temperate temperatures. Though global warming is an average, &lt;a href=&quot;https://phys.org/news/2021-05-arctic-faster-planet.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Arctic is warming several times faster than other parts of the globe&lt;/a&gt;, reducing that differential. So that suggests that, paradoxically, global warming can bring colder winters to some regions in some years, though the &lt;a href=&quot;https://www.climate.gov/news-features/understanding-climate/understanding-arctic-polar-vortex&quot; rel=&quot;nofollow noreferrer&quot;&gt;climate.gov article on the polar vortex&lt;/a&gt; notes that the question remains unresolved.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastEditorUserId="7314" LastEditDate="2022-04-08T18:06:21.683" LastActivityDate="2022-04-08T18:06:21.683" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23694" PostTypeId="1" CreationDate="2022-04-07T00:18:33.803" Score="1" ViewCount="32" Body="&lt;p&gt;Taiwan's &lt;a href=&quot;https://www.cwb.gov.tw/V8/E/P/Typhoon/TY_NEWS.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Central Weather Bureau's Current Western North Pacific Tropical Cyclones page&lt;/a&gt; shows a tropical depression with the following information:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;TROPICAL DEPRESSION&lt;/p&gt;&#xA;&lt;p&gt;TD02&lt;/p&gt;&#xA;&lt;p&gt;Position 061800Z at 4.0N 148.0E, Movement: W 4km/hr. Minimum pressure 1002 hpa, Max sustained winds near center 15 meter per second, Gusts 23 meter per second.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and the map shows it headed straight for Taiwan &amp;quot;as usual&amp;quot; :-)&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/21296/6031&quot;&gt;Why do 30% of all typhoons in the western north pacific (WNP) affect Taiwan?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Is the current (April 7, 2022 at 4.0N 148.0E) tropical depression headed towards Taiwan unusually early for the season?&lt;/p&gt;&#xA;&lt;p&gt;If so, is this a significantly early event, is it too soon to tell, or does everything seem to happen more quickly the older I get&lt;/p&gt;&#xA;&lt;p&gt;A nontechnical source &lt;a href=&quot;https://biglittleisland.com/when-is-typhoon-season-in-taiwan/&quot; rel=&quot;nofollow noreferrer&quot;&gt;When is Typhyoon Season in Taiwan? – A Guide to Surviving Taiwanese Typhyoons&lt;/a&gt; says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;And remember, &lt;strong&gt;the typhoon season starts as early as May&lt;/strong&gt; and can last till November. That means for at least half of the year, people in Taiwan have to live in fear of a major typhoon.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pd4DT.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pd4DT.jpg&quot; alt=&quot;Taiwan's Central Weather Bureau tropical depression map, 2022-04-06, TD02; Position 061800Z at 4.0N 148.0E&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;above:&lt;/strong&gt; Taiwan's Central Weather Bureau tropical depression map, 2022-04-06, TD02; Position 061800Z at 4.0N 148.0E&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2022-04-07T00:28:35.383" LastActivityDate="2022-04-07T00:28:35.383" Title="Is the current tropical depression headed towards Taiwan unusually early for the season? (April 7, 2022 at 4.0N 148.0E)" Tags="|meteorology|climate-change|climate|tropical-cyclone|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="23695" PostTypeId="1" CreationDate="2022-04-07T04:36:31.840" Score="5" ViewCount="413" Body="&lt;p&gt;As part of my pilot ground examination I got a question about cold-air inflow to the upper layers of the troposphere, the question was about the result of the inflow, The right answer was that it creates a Low in the upper troposphere and also thunderstorms.&lt;/p&gt;&#xA;&lt;p&gt;I can't get it, from my little knowledge, adding a cold heavy air to an area results in pressure raise and maybe a high pressure area but no way a low one.&lt;/p&gt;&#xA;&lt;p&gt;Can someone help me to figure out that phenomenon? I tried to google it but found no results.&lt;/p&gt;&#xA;&lt;p&gt;Attaching the relevant questions&#xA;&lt;a href=&quot;https://i.stack.imgur.com/1QQgw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1QQgw.jpg&quot; alt=&quot;question from the test&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26143" LastEditorUserId="6467" LastEditDate="2022-04-09T23:35:26.790" LastActivityDate="2023-03-13T11:24:32.167" Title="Why does cold air inflow in high tropospheric layers create a low in the upper troposphere?" Tags="|meteorology|troposphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23698" PostTypeId="2" ParentId="23695" CreationDate="2022-04-07T17:45:04.113" Score="2" Body="&lt;p&gt;You have asked an excellent question.  &lt;a href=&quot;https://weather.rap.ucar.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;This source&lt;/a&gt; was used for the illustrations shown in this answer.  The basis for the exam questions may have been an expectation that the prospective pilot would be knowledgeable of processes in meteorology at about the introductory level college or university course in meteorology. The actual circumstance regarding these two questions is one of &lt;em&gt;atmospheric processes,&lt;/em&gt; namely, the transport of colder air over warmer air along the margin of a developing low. There is no finer example of the issues presented in your question than this &lt;em&gt;actual example from today's weather.&lt;/em&gt;  Two illustrations are being shown, the first is the 500mb chart for central North America.  Dashed temperature contours (not specifically marked) are in degrees Celsius, Beaufort wind speeds are indicated in kts.  The second chart is for the current surface weather analysis at the same time as the 500mb chart. Both charts are at 1200 UTC 07 April 2022.  Let's look at the upper-air chart.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;But first, a word from our sponsor...&lt;/p&gt;&#xA;&lt;p&gt;So the question becomes, &lt;em&gt;what are we looking for in the upper air chart that specifically tells us what is happening regarding cold air transport?&lt;/em&gt;  Here are some basic guides when looking at upper-air charts -&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Airflow is always parallel to the pressure contours.&lt;/li&gt;&#xA;&lt;li&gt;Where temperature contours (dashed, as shown) are parallel to pressure contours, the transport is of air at reasonably constant temperature.&lt;/li&gt;&#xA;&lt;li&gt;Where pressure contours cross temperature contours from colder air to warmer air, the transport is of colder air into a warmer-air regime.  This is evident in the south-central US/Ohio River valley area where -20°C air is being moved into an area having -10°C air.&lt;/li&gt;&#xA;&lt;li&gt;Notice the opposite of this process is occurring in the Pacific Northwest where warmer -15°C air is being transported into an area having much colder air.&lt;/li&gt;&#xA;&lt;li&gt;Also note that the surface expression of weather features seen in upper-air charts is &lt;em&gt;typically&lt;/em&gt; or &lt;em&gt;generally&lt;/em&gt; displaced eastward for the expression of these features on the surface chart.  Consequently, the dominant upper-air high-pressure ridge from the Pacific Northwest into the southwest, is expressed as high pressure in the central Rockies region to the east.  The deep low, however, extends fully through the atmosphere with little eastward displacement from the upper atmosphere to the surface.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Now back to our program...&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;First, at 500mb (below), note the strong transport of colder air eastward over the south-central/southeast portion of the US, and the coincident (or simultaneous) &lt;em&gt;formation of a deep upper-air low&lt;/em&gt; over the north-central US. Also take related note of the transport of warmer air over colder air in the Pacific Northwest and British Columbia, and the formation of a dominant high-pressure ridge in this area and well into the southwestern US. Now let's jump below and discuss the surface weather...&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/a1eoB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/a1eoB.png&quot; alt=&quot;500mb12z07Apl2022&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here we can see, in the surface chart (below), the formation of heavy rain (and expected thunderstorms) in the US south east and into the eastern Great Lakes/St. Lawrence - southern Canada region.  Note also that the transport of the colder air portends the formation of an advancing cold front at the surface, atmospheric instability to the east of the front, and formation of rainy/stormy weather.  Note also the expression of the upper-air low at the surface with a central surface pressure of less than about 994mb. Estimated pressure at the center of this low, at 1600 UTC, is 931mb.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/y2CLv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/y2CLv.png&quot; alt=&quot;surface12z07Apl2022&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26661" LastActivityDate="2022-04-07T17:45:04.113" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23699" PostTypeId="1" CreationDate="2022-04-07T21:03:07.810" Score="1" ViewCount="59" Body="&lt;p&gt;Let me elaborate on what I mean by &amp;quot;long periods of consistent rain&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;I currently live in London and contrary to popular belief, it's not rainy. When it rains, it's usually only for 20 minutes and mixed with sunshine on the same day. I miss proper rainy days like in Paarl, South Africa where it rains for the whole day and stays grey.&lt;/p&gt;&#xA;&lt;p&gt;I want to live somewhere where I can experience multiple days like this in a row, many times a year. And preferably, when the sun shines it should also be thoroughly sunny for many days in a row.&lt;/p&gt;&#xA;&lt;p&gt;So basically, I want the opposite of London's weather. I don't want the weather to change multiple times in one day. I want long periods of sunshine and long periods of heavy rain, each lasting days on end.&lt;/p&gt;&#xA;&lt;p&gt;Where can I find a climate like this?&lt;/p&gt;&#xA;" OwnerUserId="21587" LastEditorUserId="2470" LastEditDate="2022-04-08T06:42:16.930" LastActivityDate="2022-04-08T06:42:16.930" Title="Where can I live if I like long periods of consistent rain?" Tags="|meteorology|climate|rainfall|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23702" PostTypeId="1" CreationDate="2022-04-08T03:01:16.840" Score="1" ViewCount="32" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9tKpV.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9tKpV.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Why am I incorrect? Aerosols absorb energy right? (Click the image)&lt;/p&gt;&#xA;" OwnerUserId="26665" LastActivityDate="2022-04-08T05:57:18.100" Title="Question about planetary boundary (multichoice)" Tags="|planetary-boundary-layer|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23703" PostTypeId="2" ParentId="23702" CreationDate="2022-04-08T05:57:18.100" Score="1" Body="&lt;p&gt;The correct answer is the last option about aerosols such as sulfates altering the albedo.&lt;/p&gt;&#xA;&lt;p&gt;Regarding your choice, if aerosols absorb energy, what do they do with that energy? Do they internalize the energy or do they radiate the energy out? Either way, what ultimately happens to the energy?&lt;/p&gt;&#xA;&lt;p&gt;Sulfate aerosols can change the albedo by &lt;strong&gt;reflecting&lt;/strong&gt; the energy away from Earth &amp;amp; back into the cosmos.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-04-08T05:57:18.100" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23705" PostTypeId="1" CreationDate="2022-04-08T09:31:06.883" Score="2" ViewCount="111" Body="&lt;p&gt;We know that the earth is rotating from west to east (anti-clockwise) Has the earth ever rotated from east to west in past,in early times after earth has formed?  And/or is there any scientific foresight that the earth  may rotate from east to west (clockwise) in future?&#xA;If it happens,what changes would occur?&lt;/p&gt;&#xA;" OwnerUserId="26653" LastActivityDate="2022-04-08T16:27:27.633" Title="We know that the earth is rotating from west to east.Has the earth ever rotated from east to west in past,or any possibilty it may in future?" Tags="|earth-rotation|" AnswerCount="1" CommentCount="5" ClosedDate="2022-04-14T02:04:48.500" ContentLicense="CC BY-SA 4.0" />
  <row Id="23706" PostTypeId="2" ParentId="23705" CreationDate="2022-04-08T13:43:19.427" Score="3" Body="&lt;h3&gt;No.&lt;/h3&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;I'm not aware of any evidence that Earth ever rotated in the opposite direction in the past.&lt;/li&gt;&#xA;&lt;li&gt;It's very unlikely that it will have its direction reversed, e.g. by a very large bolide, in the future.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;For future reversals, I can think of 2 scenarios: slowing down and reversing, or flipping the rotational axis.&lt;/p&gt;&#xA;&lt;h3&gt;Slow down and reverse&lt;/h3&gt;&#xA;&lt;p&gt;I think we can discount the case of reversal by abruptly (in the geological sense) stopping it then accelerating in the opposite sense. For example, assuming the Earth has &lt;a href=&quot;https://en.wikipedia.org/wiki/Rotational_energy&quot; rel=&quot;nofollow noreferrer&quot;&gt;rotational kinetic energy&lt;/a&gt; of 2 × 10&lt;sup&gt;29&lt;/sup&gt; J, reversing its direction would require a change of twice this number. This is at least a million times the energy released in &lt;a href=&quot;https://en.wikipedia.org/wiki/Chicxulub_crater&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Chicxulub impact&lt;/a&gt; (about 3×10&lt;sup&gt;23&lt;/sup&gt; J).&lt;/p&gt;&#xA;&lt;p&gt;This is all very rough, we're ignoring its total orbital momentum and assuming its a spherical solid, but it seems like it would be hard to find this much energy, especially in today's solar system.&lt;/p&gt;&#xA;&lt;p&gt;There's &lt;a href=&quot;https://earthscience.stackexchange.com/questions/236/will-the-earth-ever-stop-rotating&quot;&gt;an old question&lt;/a&gt; about the possibility of the Earth eventually running out of angular momentum. If you accept that this might happen in several (probably tens of) billions of years, then I suppose it could be started again by a bolide impact... except that bolide impacts will be impossibly rare events by then.&lt;/p&gt;&#xA;&lt;h3&gt;Flip the axis&lt;/h3&gt;&#xA;&lt;p&gt;Most of the answers I could find are just as speculative as the question itself, and they seem to focus on a reversal of rotation direction. But none of them address the possibility of the Earth's axis flipping 180 degrees with respect to the ecliptic, which would effectively reverse the rotation. (Really, since it's already titled by 23.4 degrees, only another 68 degrees would push the North pole over the ecliptic.). There's &lt;a href=&quot;https://physics.stackexchange.com/questions/613448/energy-required-to-tilt-earth-s-axis-by-90-degrees&quot;&gt;a Physics Stack Exchange&lt;/a&gt; question about this, and thanks to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Gyroscope&quot; rel=&quot;nofollow noreferrer&quot;&gt;gyroscope&lt;/a&gt; effect, the energy required to shift the axis is almost the same as that required to reverse the spin.&lt;/p&gt;&#xA;&lt;p&gt;Conclusion: this is just as unlikely as the first scenario.&lt;/p&gt;&#xA;&lt;h3&gt;Further reading&lt;/h3&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;There's a good thread on all this &lt;a href=&quot;https://astronomy.stackexchange.com/questions/40768/will-earth-rotate-backwards-in-the-future&quot;&gt;over on the Astronomy Stack Exchange&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Here's &lt;a href=&quot;https://indd.adobe.com/view/f6592f4d-f2e3-4315-8afc-1b6f9588040f&quot; rel=&quot;nofollow noreferrer&quot;&gt;a poster&lt;/a&gt; about how climate would be affected by a reverse-rotating Earth.&lt;/li&gt;&#xA;&lt;li&gt;There's &lt;a href=&quot;https://physics.stackexchange.com/questions/29235/would-it-matter-if-the-earth-rotated-clockwise&quot;&gt;a Physics Stack Exchange&lt;/a&gt; question about what else would be affected.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2022-04-08T16:27:27.633" LastActivityDate="2022-04-08T16:27:27.633" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23707" PostTypeId="1" AcceptedAnswerId="23708" CreationDate="2022-04-08T16:56:52.867" Score="4" ViewCount="283" Body="&lt;p&gt;I'm looking to retrieve from weather forecasts (such as GFS or HRRR) the U and V component of the wind with respect to some altitude (meters) above mean sea level.&lt;/p&gt;&#xA;&lt;p&gt;To do so, I've implement a interpolate following the same idea as in the link below.&#xA;&lt;a href=&quot;https://stackoverflow.com/a/61107634/6528830&quot;&gt;https://stackoverflow.com/a/61107634/6528830&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, I'm confused by the results it would seem like part of some pressure level would be underground.&lt;/p&gt;&#xA;&lt;p&gt;If I look at the geopotential height @ ground or water surface. It seems to match with terrain elevation. Yet I don't believe it matched exactly, is this normal?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/sE4Gv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sE4Gv.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, it's the 1000 mb geopotential that really confuses me:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/XK0r1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XK0r1.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;How could some points be lower that in the gph@ground?&#xA;What am I not understanding about this data and how can I use it to figure out what is the wind at specifics altitudes above mean sea level?&lt;/p&gt;&#xA;" OwnerUserId="26668" LastEditorUserId="2470" LastEditDate="2022-04-08T17:27:02.467" LastActivityDate="2022-04-08T19:34:39.440" Title="How to find the altitude above mean sea level of the wind in forecast data such as GFS" Tags="|wind|gfs|altitude|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23708" PostTypeId="2" ParentId="23707" CreationDate="2022-04-08T17:50:59.817" Score="4" Body="&lt;p&gt;It makes sense, some locations have a surface pressure under 1000 mb... which means to get to 1000 mb you'd have to go below ground (the basic idea of the calculation is that pressure decreases as you ascend in the atmosphere... so to get it to increase from sea level pressure, you'd have to go the other direction, underground).&lt;/p&gt;&#xA;&lt;p&gt;It certainly feels hints of being unrealistic... but I would think if you dug such a deep enough hole wide enough, you would get to the given pressure.&lt;/p&gt;&#xA;&lt;p&gt;Here's the sea level pressure map similar to your 1000 mb map:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/z8A6f.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/z8A6f.png&quot; alt=&quot;[1]: https://i.stack.imgur.com/POw1P.png&quot; /&gt;&lt;/a&gt;&#xA;(Source: &lt;a href=&quot;https://www.weathernerds.org/models/gfs.html?&amp;amp;inittype=zoom&amp;amp;initfield=Temperature_Surface&amp;amp;initcycle=determine&amp;amp;initfhour=000&amp;amp;initimdimx=1050&amp;amp;initimdimy=630&amp;amp;initrange=90.000000000000:0:-90.000000000000:360.000000000000&amp;amp;initcx1=0&amp;amp;initcy1=0&amp;amp;initcx2=0&amp;amp;initcy2=0&amp;amp;initcross=False&amp;amp;initsound=False&amp;amp;initsoundx=1&amp;amp;initsoundy=1&amp;amp;initloop=False&amp;amp;initoverlay=False&amp;amp;initlstart=000&amp;amp;initlend=384&amp;amp;initlint=6&amp;amp;initol1=Temperature_Surface&amp;amp;initol2=null&amp;amp;initol3=null&amp;amp;initol4=null&amp;amp;initol5=null&amp;amp;initcities=On&amp;amp;inithgwys=On&amp;amp;initunits=On&amp;amp;initlatlon=Off&quot; rel=&quot;nofollow noreferrer&quot;&gt;weathernerds.org&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;Those negative height areas indeed match a chain of lows with surface pressure below 1000 mb in the Southern Ocean and a 992 mb low over Europe.  So if the station is 992 mb... you'd have to even lower in the atmosphere (= negative) to get to 1000 mb.&lt;/p&gt;&#xA;&lt;p&gt;This is actually a common interpolation on pressure maps in meteorology... mean sea level pressure itself... probably the most common map we use... is found at a height that is actually below ground at most places, because almost all locations are somewhat above sea level.  But by comparing on a flat surface it allows us to better identify the weather-causing features, factoring out the otherwise overwhelming factor of pressure decrease with altitude above sea level (your ears pop on mountains despite being at 0 ft above the ground because the atmospheric pressure is still less because there's less atmosphere above you)&lt;/p&gt;&#xA;&lt;p&gt;Even at 850 mb, another common geopotential height for analysis... we can plot the heights above sea level... but we often will choose to mask out the model's winds in spots to show the 850 height is truly subterranean there, so the model's predicted winds are of imaginary quality, being below ground level:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cxa19.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cxa19.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;(From &lt;a href=&quot;https://www.pivotalweather.com/model.php?m=gfs&amp;amp;p=850wh&amp;amp;rh=2022040812&amp;amp;fh=loop&amp;amp;r=as&amp;amp;dpdt=&amp;amp;mc=&quot; rel=&quot;nofollow noreferrer&quot;&gt;pivotalweather&lt;/a&gt;)... the grey is masked out wind.&lt;/p&gt;&#xA;&lt;p&gt;So all your plots looks quite reasonable, and hopefully that helps make sense of the concept.  Not every location has 1000 mb (or even 850 mb) in its atmosphere... both because some sites have sea-level pressures below that value (the cause of the issues on your map, &lt;a href=&quot;https://en.wikipedia.org/wiki/Geopotential_height&quot; rel=&quot;nofollow noreferrer&quot;&gt;as geopotential is based upon sea-level&lt;/a&gt;), and also because the elevation of some sites means lower surface pressure (not the cause of your negative geopotential heights, but the cause of the wind maskout on some such plots as shown).&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-04-08T19:34:39.440" LastActivityDate="2022-04-08T19:34:39.440" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23710" PostTypeId="1" CreationDate="2022-04-09T20:17:10.340" Score="2" ViewCount="69" Body="&lt;p&gt;I'm not sure if this is the right section to post this, but since it's about weather and statistics I am posting it here first.&lt;/p&gt;&#xA;&lt;p&gt;I tried using R's qmap package to do a simple experiment using this function below for observed and modeled data.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;fitQmap(obs,mod,method=c(&amp;quot;PTF&amp;quot;,&amp;quot;DIST&amp;quot;,&amp;quot;RQUANT&amp;quot;,&amp;quot;QUANT&amp;quot;,&amp;quot;SSPLIN&amp;quot;),...)&#xA;doQmap(x, fobj, ...)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;The figure below shows the PDF (obs. and mod.) uncorrected and corrected.&lt;/p&gt;&#xA;&lt;p&gt;How would you exactly interpret the results?&lt;/p&gt;&#xA;&lt;p&gt;I noticed that observed values had events of higher wind speeds and the the model did not. What physical property can suggest such thing?&lt;/p&gt;&#xA;&lt;p&gt;Also, since the corrected modeled one almost &lt;strong&gt;exactly&lt;/strong&gt; matches the observed one, does this mean there is overfitting? How would I know if it weren't overfitted to the model?&lt;/p&gt;&#xA;&lt;p&gt;Thanks for any help or suggestion!&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MQvtq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MQvtq.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="17926" LastActivityDate="2022-04-09T20:17:10.340" Title="Empirical quantile mapping" Tags="|meteorology|climate-models|statistics|r|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23711" PostTypeId="1" CreationDate="2022-04-10T15:24:07.893" Score="3" ViewCount="50" Body="&lt;p&gt;If we somehow removed all the water from Earth, it seems that there would no longer&#xA;be tornado-like 100+ mph winds (or, at least, this would be a much rarer occurrence).&#xA;Discussing storm creation, however, gets complicated, so let me instead ask here about&#xA;storm maintenance.&lt;/p&gt;&#xA;&lt;p&gt;What would happen to a tornado-forming supercell or hurricane if we could somehow&#xA;switch off water's phase transformation?  In other words, in an accurate simulation&#xA;of these storms, if we suddenly (in the middle of a strong storm) disabled water&#xA;condensation into droplets (and disabled the reverse evaporation process, which&#xA;might be important for hurricanes), would wind speeds be significantly lower after,&#xA;say, 10 minutes?  How much lower?&lt;/p&gt;&#xA;&lt;p&gt;I'm trying to understand how much the thermal heat of vaporization and the&#xA;rapid falling of droplets physically &amp;quot;stir&amp;quot; the storm (e.g., from &lt;a href=&quot;https://en.wikipedia.org/wiki/Convective_instability&quot; rel=&quot;nofollow noreferrer&quot;&gt;convective instability&lt;/a&gt;).  The simplest picture of&#xA;tornado development just requires a low-pressure center, but most sources say that&#xA;the dew point is usually above 55F, so water plays some role.  Is there any&#xA;published simulation to help quantify this role?  For a hurricane, it especially&#xA;seems that some physical property of water is crucial (beyond just providing a&#xA;good source of heat from the ocean's high thermal mass, as the textbook explanation&#xA;of a hurricane describes it).&lt;/p&gt;&#xA;" OwnerUserId="18294" LastEditorUserId="18294" LastEditDate="2022-04-15T22:12:58.990" LastActivityDate="2022-04-15T22:12:58.990" Title="How important is water condensation in maintaining the swirling winds of tornadoes?" Tags="|water|wind|tropical-cyclone|storms|tornado|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23713" PostTypeId="2" ParentId="6656" CreationDate="2022-04-11T08:25:53.183" Score="0" Body="&lt;p&gt;If you wish to convert &lt;em&gt;west-east longitude&lt;/em&gt; to &lt;strong&gt;eastward longitude&lt;/strong&gt;, you can use the loop below, where lon represents your matrix with &lt;em&gt;west-east longitude&lt;/em&gt;:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;N = length (lon)&#xA;&#xA;long = abs (lon);&#xA;&#xA;i=1;&#xA;&#xA;while i&amp;lt;N+1;&#xA;&#xA;  eastward_long(i) = (long(i) - floor(long(i) / 360) * 360) * (lon(i) / long(i)) - 180 * ((lon(i) / long(i)) - 1); &#xA;&#xA;  i = i + 1;&#xA;&#xA;end&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="26675" LastEditorUserId="81" LastEditDate="2022-04-11T09:48:36.440" LastActivityDate="2022-04-11T09:48:36.440" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23714" PostTypeId="1" CreationDate="2022-04-11T23:13:09.007" Score="1" ViewCount="125" Body="&lt;p&gt;If I walk up to a pier and throw kool aid into the ocean, where will those kool aid particles end up on a long enough time scale? Is it arbitrary? Will they travel the entire ocean at one point?&lt;/p&gt;&#xA;" OwnerUserId="26678" LastActivityDate="2022-04-12T08:23:58.673" Title="How far do substances travel when thrown into the ocean?" Tags="|oceanography|ocean-currents|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23715" PostTypeId="2" ParentId="23714" CreationDate="2022-04-12T02:21:16.357" Score="2" Body="&lt;p&gt;It depends on what is thrown in, how much of it is thrown in where it is thrown in and the ocean currents in the region and the chemical properties and reactivity of what has been thrown into the ocean.&lt;/p&gt;&#xA;&lt;p&gt;To paraphrase researchers from &lt;a href=&quot;https://www.whoi.edu/press-room/news-tip/faqs-radiation-from-fukushima/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Woods Hole Oceanographic Institute,&lt;/a&gt; anything that is dissoluble in sea water begins mixing with sea water and becomes increasing dilute. Depending on how soluble the substance is, it may react with either the water or with other molecules in the water to form alternate compounds. As the substance moves offshore it will then be taken across the ocean by currents. Depending on the longevity and traceability of the compounds they could end in most of the oceans of the world.&lt;/p&gt;&#xA;&lt;p&gt;If you threw a small amount of cool aid in the ocean it would quickly disperse. A larger amount would take longer to disperse.&lt;/p&gt;&#xA;&lt;p&gt;Radioactive elements from the Fukushima power plant that exploded after being damaged by a tsunami in 2011 took &lt;a href=&quot;https://earthsky.org/earth/tracking-fukushima-radiation-across-the-pacific/&quot; rel=&quot;nofollow noreferrer&quot;&gt;2.1 years&lt;/a&gt; to reach the western shores of North American.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2022-04-12T08:23:58.673" LastActivityDate="2022-04-12T08:23:58.673" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23717" PostTypeId="1" CreationDate="2022-04-12T10:35:33.767" Score="2" ViewCount="68" Body="&lt;p&gt;I want to apply PCA to geopotential height (obtained from ERA5) to find the patterns. The way  have created the dataset is: The columns are different locations (latitude/longitute) and the rows are different time steps. The values are geopotential height a different location at different times. I ran pca in this dataset I would like to create the maps of the patterns (see the picture an example). I am not sure how to do this. Should I plot the eigenvectors for each PCA as a contour plot? I can see that in the picture there is the geopotential height and not the eigenvectors. Any help woould be great!&#xA;&lt;a href=&quot;https://i.stack.imgur.com/11a5l.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/11a5l.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26681" LastActivityDate="2022-04-12T10:35:33.767" Title="Plot maps from principal component analysis to geopotential height" Tags="|meteorology|statistics|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23719" PostTypeId="1" CreationDate="2022-04-12T15:35:07.543" Score="1" ViewCount="49" Body="&lt;p&gt;Do you know what is the difference between EOFs S mode and T mode? I want to find the spatial patterns and I have a time series for values at each location.&lt;/p&gt;&#xA;&lt;p&gt;Thanks in advance!&lt;/p&gt;&#xA;" OwnerUserId="26681" LastActivityDate="2022-04-12T15:35:07.543" Title="EOFs T mode vs S mode" Tags="|meteorology|statistics|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23720" PostTypeId="2" ParentId="13731" CreationDate="2022-04-13T07:11:24.333" Score="0" Body="&lt;p&gt;Before earth had water on it's surface, two main types of rocks formed to create continental plates.&#xA;basaltic rock&#xA;&lt;a href=&quot;https://i.stack.imgur.com/5xsae.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5xsae.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;and Granitic rock&#xA;&lt;a href=&quot;https://i.stack.imgur.com/oemws.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oemws.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Continental crustal material is just sligtly less dense than basaltic rock because when heavier basaltic rock is subducted under the continents and melts once again, the lighter such elements like aluminum and silicon on the otherhand tend to move upward and the heavier elements and minerals like Iron migrate down. That makes for the iron-rich portions on the other hand are being recycled back into the mantle and the silicon rich rocks ascending to the surface. Volcanic eruptions that occur above the ocean may deposit new basaltic rock in turn weighing down continental plates but it's continuous activity however granite's higher melting point means more weight must be contributed&#xA;&lt;a href=&quot;https://i.stack.imgur.com/YsOO0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YsOO0.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastEditorUserId="21028" LastEditDate="2022-04-14T02:51:56.930" LastActivityDate="2022-04-14T02:51:56.930" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23721" PostTypeId="1" CreationDate="2022-04-14T11:46:19.340" Score="4" ViewCount="154" Body="&lt;p&gt;The 2-layer hydrostatic model is like this&lt;a href=&quot;https://i.stack.imgur.com/t3mjG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/t3mjG.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;And the pressure of the two layers and the top are&lt;a href=&quot;https://i.stack.imgur.com/VDxAm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VDxAm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;and it is easy to find the horizontal gradient of &lt;span class=&quot;math-container&quot;&gt;$p_1$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$p_2$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\begin{aligned}&#xA;\nabla p_1 &amp;amp;= \nabla p_H\\&#xA;\nabla p_2 &amp;amp;= \nabla p_H + g(\rho_2 - \rho_1)\nabla h_2\\&#xA;\end{aligned}&#xA;\end{equation}&lt;/span&gt;&#xA;Now my problem is that how to get the result&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;p_2 - p_1 = g(\rho_2 - \rho_1)\eta &#xA;\end{equation}&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;from the equations above, where&lt;span class=&quot;math-container&quot;&gt;$\eta = h_2 - H_2$&lt;/span&gt;. I find this result in the book&amp;quot;&lt;a href=&quot;http://people.atmos.ucla.edu/jcm/GFD_book.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fundamentals of Geophysical Fluid&#xA;Dynamics&lt;/a&gt;&amp;quot; at page 164.&lt;/p&gt;&#xA;" OwnerUserId="21802" LastActivityDate="2022-04-16T08:40:57.650" Title="A problem of the 2-Layer hydrostatic model" Tags="|models|atmosphere-modelling|fluid-dynamics|ocean-models|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="23722" PostTypeId="2" ParentId="23721" CreationDate="2022-04-15T10:43:02.770" Score="5" Body="&lt;p&gt;Let's say our goal is to find &lt;span class=&quot;math-container&quot;&gt;$\eta$&lt;/span&gt; which is the displacement of the fluid relative to its resting position at &lt;span class=&quot;math-container&quot;&gt;$z = H_2$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;We find&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\begin{split}&#xA;p_2 - p_1 &amp;amp;= \require{cancel} \bcancel{p_H} + \rho_1 g(\require{cancel} \bcancel{H}-h_2) + \rho_2g(h_2 - z) \require{cancel} \bcancel{-p_H} - \rho_1g(\require{cancel} \bcancel{H}-z) \\&#xA;&amp;amp;= (\rho_2 - \rho_1)gh_2 - (\rho_2 - \rho_1)gz \\&#xA;&amp;amp; = (\rho_2 - \rho_1)g(H_2 + \eta) - (\rho_2 - \rho_1)gz&#xA;\end{split}&#xA;\end{equation}&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Dividing by &lt;span class=&quot;math-container&quot;&gt;$(\rho_2 - \rho_1)g$&lt;/span&gt; yields&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA; \eta + H_2 - z =  \frac{p_2 - p_1}{(\rho_2 - \rho_1)g}. &#xA;\end{equation}&lt;/span&gt;&#xA;The equation above tells us the distance to the interface at some height &lt;span class=&quot;math-container&quot;&gt;$z$&lt;/span&gt; (remember the coordinate origin is at the bottom of the domain). We are interested in the displacement relative to the mean interface height &lt;span class=&quot;math-container&quot;&gt;$z = H_2$&lt;/span&gt;, so we have&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA; \eta  =  \frac{p_2 - p_1}{(\rho_2 - \rho_1)g},&#xA;\end{equation}&lt;/span&gt;&#xA;which is the result you are looking for. However, in the document they say that they use four more equations to derive the result. Maybe it's a mistake or maybe I'm missing something.&lt;/p&gt;&#xA;&lt;p&gt;I was a little confused that you said we can find the result in the document - so for anyone wondering:&lt;/p&gt;&#xA;&lt;p&gt;Using &lt;span class=&quot;math-container&quot;&gt;$\phi_n = p_n / \rho_0$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$g' = g(\rho_2 - \rho_1)/\rho_0$&lt;/span&gt;, we find&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA; \eta  =  \frac{(p_2 - p_1)\rho_0}{(\rho_2 - \rho_1)g\rho_0} = -\frac{\phi_1 - \phi_2}{g'},&#xA;\end{equation}&lt;/span&gt;&#xA;which corresponds to what's shown in the document.&lt;/p&gt;&#xA;" OwnerUserId="18833" LastEditorUserId="18833" LastEditDate="2022-04-16T08:40:57.650" LastActivityDate="2022-04-16T08:40:57.650" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23723" PostTypeId="1" CreationDate="2022-04-15T12:17:51.293" Score="7" ViewCount="98" Body="&lt;p&gt;When Joseph Kittinger in Excelsior III dwelt at his peak altitude of 102,000 ft (31 km), he &lt;a href=&quot;https://www.nationalgeographic.com/science/article/121008-joseph-kittinger-felix-baumgartner-skydive-science&quot; rel=&quot;noreferrer&quot;&gt;reportedly saw clouds at his altitude&lt;/a&gt;. What in the world could these clouds have been? Polar stratospheric clouds don't form as much south as Kittinger has been, do they? And noctilucent clouds form much higher, in the mesosphere. So what clouds could that have been? Kittinger says they had been seen at earlier times. Have they been observed by near-space balloons or SR-71 pilots afterwards?&lt;/p&gt;&#xA;" OwnerUserId="26511" LastActivityDate="2022-04-24T07:50:26.887" Title="What kind of clouds did Joseph Kittinger see at 102,000 ft?" Tags="|meteorology|atmosphere|clouds|stratosphere|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23724" PostTypeId="1" CreationDate="2022-04-16T02:22:34.867" Score="1" ViewCount="44" Body="&lt;p&gt;I am not a scientist but how does carbon dioxide make its way to the upper atmosphere form fossil fuel burning if it is heavier than oxygen (air), especially as the air is thinner in the upper as you go higher in the atmosphere&lt;/p&gt;&#xA;" OwnerUserId="24806" LastActivityDate="2022-04-16T02:22:34.867" Title="How does carbon dioxide accumulate in the upper atmosphere if it is heavier than air" Tags="|climate-change|temperature|carbon-cycle|" AnswerCount="0" CommentCount="9" ClosedDate="2022-04-16T23:32:06.820" ContentLicense="CC BY-SA 4.0" />
  <row Id="23725" PostTypeId="1" CreationDate="2022-04-16T05:28:01.477" Score="2" ViewCount="44" Body="&lt;p&gt;Do you know of any database where I can get past air pollution (sulfur oxides (SOx) - nitrogen oxides (NOx) - photochemical oxidants (Ox) - particulate matter (PM) - suspended particulate matter (SPM) - fine particulate matter (PM2.5), etc.) as predicted values on a grid map of Japan?&#xA;Or do you know of any studies using such data?&#xA;I can find some by prefecture and by base station.&lt;/p&gt;&#xA;" OwnerUserId="26696" LastEditorUserId="5594" LastEditDate="2022-04-16T11:10:18.973" LastActivityDate="2022-04-16T11:10:18.973" Title="gridded air pollution data for Japan" Tags="|meteorology|air-pollution|database|japan|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23726" PostTypeId="1" AcceptedAnswerId="23731" CreationDate="2022-04-16T19:00:19.073" Score="3" ViewCount="181" Body="&lt;p&gt;In Mallorca, Spain, there is a river called Torrent Son Bauló. As visible in the picture, it ends just before the sea, seemingly blocked by the beach. What can be the cause of that?&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://cf.bstatic.com/xdata/images/hotel/max500/260429036.jpg?k=b1080d5e5b2512f516feb8aa6aca1bf8764e5aa9a405d0fcde7c581f4df659d8&amp;amp;o=&amp;amp;hp=1&quot; alt=&quot;&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;My guess is that the water is absorbed by the sand and flows into the sea through it, or that it doesn't have enough discharge and simply soaks into the ground and/or evaporates.&lt;/p&gt;&#xA;&lt;p&gt;Also, are there any other rivers that behave similarly?&lt;/p&gt;&#xA;" OwnerUserId="26699" LastEditorUserId="6129" LastEditDate="2022-04-17T12:56:19.383" LastActivityDate="2022-04-18T00:52:16.487" Title="What can make a river end just before an ocean?" Tags="|hydrology|rivers|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23727" PostTypeId="1" CreationDate="2022-04-17T16:15:35.650" Score="20" ViewCount="5797" Body="&lt;p&gt;As the Earth's axis is inclined, during summer in the northern hemisphere places in the north are exposed to the Sun's rays for longer, so days are longer during summer (say in June - Aug). Yet, countries like the UK have a lower summer temperature than countries like India, particularly given that the UK is to the north of India and has longer days in summers). I was just wondering about this. Feel free to share your insights.&lt;/p&gt;&#xA;" OwnerUserId="26703" LastEditorUserId="-1" LastEditDate="2022-04-19T08:09:29.147" LastActivityDate="2022-04-20T00:55:59.333" Title="In the northern hemisphere summer, why are places in the north cooler than those in the south?" Tags="|meteorology|climate|earth-rotation|sun|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23728" PostTypeId="2" ParentId="23727" CreationDate="2022-04-17T20:18:14.383" Score="33" Body="&lt;p&gt;The image below (apparently from &amp;quot;physicalgeography.net&amp;quot; is somewhat instructive:&lt;/p&gt;&#xA;&lt;p&gt;Notice that even in the middle of summer, India (at about 30 °N) still gets slightly more sun than the Britain (at 60 °N). That's because although the days are longer in Britain, the sun is lower in the sky and so its heat is spread out over a wider area.&lt;/p&gt;&#xA;&lt;p&gt;But the North Pole gets even more sun than either Britain or India in June, and the equator gets substantially less. So there is something to explain. The reason is thermal inertia.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9CSGe.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9CSGe.png&quot; alt=&quot;Graph of insolation per month at different latitudes&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;This graph shows insolation averaged over 24 hours at four different Latitudes. This shows the theoretical insolation. The model used to calculate these curves includes the effects of Earth's elliptical orbit, but do not take account of any atmospheric effects, such as the energy absorbed by the atmosphere, nor any weather effects such as clouds. It shows that a perfectly black disc with an area of 1 m² placed just above the atmosphere and oriented horizontal to the Earth surface would receive an average of about 515 Joules per second at the North Pole on June 21st and an average of about 380 Joules per second at the Equator.  The main reason for the Equator value being so low is that it is night time for about 12 hours at the equator.&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;Imagine pushing a heavy ball. It can take some time for it to begin to move quickly because it has inertia. Similarly, it takes time for the ground and water to heat up when the sun shines upon them. India gets much more sun in winter, and so the ground and water remain warm.  When summer comes, it heats up further and ends up much hotter than Britain.  In Britain there is very little sun in winter, and the ground and water cool down (and freeze). Then, even when the sun comes in summer, it takes time to warm up. By the time the ground and water have warmed up, the sun is already starting to weaken. And so the temperature never rises as much as it can in India.&lt;/p&gt;&#xA;&lt;p&gt;There are lots of details and local effects (the gulf stream in Britain, and the monsoon in India are significant) but the basic reason that India is hotter &lt;em&gt;in summer&lt;/em&gt; is that it gets more sun &lt;em&gt;in winter&lt;/em&gt;!&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.physicalgeography.net/fundamentals/6i.html&quot; rel=&quot;noreferrer&quot;&gt;Pidwirny, M. (2006). &amp;quot;Earth-Sun Relationships and Insolation&amp;quot;. Fundamentals of Physical Geography, 2nd Edition.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="9563" LastEditorUserId="9563" LastEditDate="2022-04-19T17:17:03.250" LastActivityDate="2022-04-19T17:17:03.250" CommentCount="26" ContentLicense="CC BY-SA 4.0" />
  <row Id="23730" PostTypeId="2" ParentId="23689" CreationDate="2022-04-17T23:50:04.613" Score="5" Body="&lt;p&gt;A news article fro April 18, 2022,  &lt;em&gt;&lt;a href=&quot;https://www.abc.net.au/news/science/2022-04-18/1-5-vs-2c-degrees-warming-difference-climate-global/100981866&quot; rel=&quot;noreferrer&quot;&gt;1.5 vs 2C: What difference can a lousy half a degree of global warming make?&lt;/a&gt;&lt;/em&gt;, makes reference to the article, &lt;em&gt;&lt;a href=&quot;https://www.nature.com/articles/s41586-022-04553-z.epdf?sharing_token=YH7qcOQWOAYwcByrbNobC9RgN0jAjWel9jnR3ZoTv0M300RSN_AgLPC24xTg-EsjBHT--C2URS0u7zmcqcM_N1toRTe8fS7Em9Tgshq86LNuelKaYIBy7YOfme6fA8CJ6qiaOvEset7HZuivmDp8OebYr2RMP1lRWWxATCADzq-MDqaNRumiH5l8ZrU67rzIwIJ75MoqojCj1en5WGf4BP7yC9h_2nNE2KPbu93nTi0%3D&amp;amp;tracking_referrer=www.abc.net.au&quot; rel=&quot;noreferrer&quot;&gt;Realization of Paris Agreement pledges may limit warming just below 2 °C&lt;/a&gt;&lt;/em&gt; published in Nature Magazine. It quantifies the affects of the difference, this way:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A report by &lt;a href=&quot;https://interactive.carbonbrief.org/impacts-climate-change-one-point-five-degrees-two-degrees/#&quot; rel=&quot;noreferrer&quot;&gt;Carbon Brief&lt;/a&gt;, which analysed 70 research papers comparing 1.5 °C and 2 °C , found that globally we can expect an average of about 56 centimetres of sea level rise this century at 2°C  — but up to 96cm in the worst-case scenario.&lt;/p&gt;&#xA;&lt;p&gt;That's about 10cm more, on average, when compared to 1.5°C .&lt;/p&gt;&#xA;&lt;p&gt;That extra 10cm, according to the IPCC, is expected to impact an extra 10.4 million people, either directly through inundation of coastal homes or through crippling of food-growing lands and livelihoods.&lt;/p&gt;&#xA;&lt;p&gt;Many of those 10.4 million, including residents of some of the low-lying islands of our Pacific region, are expected to become climate refugees.&lt;/p&gt;&#xA;&lt;p&gt;Sea-level rise doesn't happen equally around the globe. One variable is what is called gravitational self-attraction.&lt;/p&gt;&#xA;&lt;p&gt;Things with mass have gravity, and things with huge mass like the Greenland and Antarctic ice sheets have enough gravity that they pull the oceans towards them.&lt;/p&gt;&#xA;&lt;p&gt;As their mass is reduced, the seas will settle out towards the lower latitudes, causing more substantial rises around the tropics and sub-tropics&lt;/p&gt;&#xA;&lt;p&gt;At 1.5°C , the Northern Hemisphere can also expect an ice-free Arctic summer around every once in 33 years, rising to around once every seven years at 2°C  (and nearly two in every three years at 3°C ).&lt;/p&gt;&#xA;&lt;p&gt;An extra 1.5 to 2.5 million square kilometres of permafrost will also melt at 2°C  by 2300.&lt;/p&gt;&#xA;&lt;p&gt;Though weather varies regionally, on average we can expect longer, more intense droughts, longer, hotter heatwaves and fewer but more extreme rainfall events at both 1.5°C  and 2°C .&lt;/p&gt;&#xA;&lt;p&gt;According to the Carbon Brief report, globally we can expect a 16 per cent increase in hot days each year at 1.5°C , and a 25 per cent increase or 35 more hot days each year at 2°C .&lt;/p&gt;&#xA;&lt;p&gt;Just over a seventh of the world's population will face a severe heat wave at least once in five years at 1.5°C , but that jumps to more than a third at 2°C , and the frequency of warm extremes jumps by 343 per cent at 2°C .&lt;/p&gt;&#xA;&lt;p&gt;An extra 62 million people will be exposed to drought each year if we reach 2°C , compared to 1.5°C .&lt;/p&gt;&#xA;&lt;p&gt;Tropical cyclones are expected to become less frequent, but extreme cyclones are predicted to be more intense when they do hit.&lt;/p&gt;&#xA;&lt;p&gt;At 2°C , an extra 12 million people are expected to be flooded in coastal areas each year compared to at 1.5°C .&lt;/p&gt;&#xA;&lt;p&gt;In northern Africa, for instance, the average drought is predicted to be 7 months longer at 1.5C versus 20 months longer at 2C (at 3C, it's 60 months longer).&lt;/p&gt;&#xA;&lt;p&gt;In East Africa, 6 million more people are expected to suffer water scarcity at 1.5°C . At 2°C , that rises to 22 million more people.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-04-17T23:50:04.613" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23731" PostTypeId="2" ParentId="23726" CreationDate="2022-04-18T00:52:16.487" Score="3" Body="&lt;p&gt;Looking at the region in question via &lt;a href=&quot;https://earth.google.com/web/@39.75600401,3.16785041,9.52638005a,1337.3656543d,35y,0h,0t,0r&quot; rel=&quot;nofollow noreferrer&quot;&gt;Google Earth&lt;/a&gt;, reveals the following scene.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/11w0a.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/11w0a.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Following the so called river past the &lt;a href=&quot;https://www.openstreetmap.org/search?query=Torrent%20Son%20Baul%C3%B3#map=15/39.7541/3.1681&quot; rel=&quot;nofollow noreferrer&quot;&gt;major road&lt;/a&gt;, &lt;em&gt;Carratera d'Artà&lt;/em&gt; reveals the so called river is derived from a very small water course, similar to a small creek.&lt;/p&gt;&#xA;&lt;p&gt;The region of the &amp;quot;river&amp;quot; displayed in the question appears to be more like a lake or some form pond.&lt;/p&gt;&#xA;&lt;p&gt;Based on this, I would suggest the Torrent Son Bauló is a very low flowing creek which does not have the capacity to break through the sand barrier imposed by the beach. Subsequently, the water in the &amp;quot;river&amp;quot; forms a pond/lake and the back side of the beach.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-04-18T00:52:16.487" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23732" PostTypeId="2" ParentId="23727" CreationDate="2022-04-18T02:18:59.433" Score="12" Body="&lt;p&gt;Hours of sunlight are not the only factor that determines insolation (solar energy at the surface).&lt;/p&gt;&#xA;&lt;p&gt;Thought experiment: spread a bed sheet on the floor, switch the lights off, and shine a flashlight directly down on that bed sheet from about one foot above it. You will get a small, fairly bright spot of light on the sheet.&lt;/p&gt;&#xA;&lt;p&gt;Now tilt the flashlight, and shine it across it at a flat angle - say, 45 or 60 degrees - still keeping it about one foot away from the spot it's illuminating. As you flatten the angle, that spot elongates to cover a larger and larger area. But the amount of light coming out of the flashlight is still the same, spread over a larger area, which means lower intensity on the sheet. The same amount of light that was previously hitting a 100 cm&lt;sup&gt;2&lt;/sup&gt; spot might now be spread across 500 cm&lt;sup&gt;2&lt;/sup&gt;.&lt;/p&gt;&#xA;&lt;p&gt;This is part of what's happening at the high latitudes. During the summer months they are getting many hours of sunlight, but they're not getting a lot of energy per square metre compared to the tropics. In early April, the North Pole is getting sunlight 24 hours a day, but much &lt;em&gt;less&lt;/em&gt; sunlight (in terms of energy/m&lt;sup&gt;2&lt;/sup&gt; etc.) than the equator gets in 12.)&lt;/p&gt;&#xA;" OwnerUserId="26707" LastEditorUserId="26707" LastEditDate="2022-04-20T00:55:59.333" LastActivityDate="2022-04-20T00:55:59.333" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23733" PostTypeId="2" ParentId="23145" CreationDate="2022-04-18T18:13:52.797" Score="5" Body="&lt;p&gt;It sounds like you're looking for flow accumulation (upstream) area, most likely.  That's imperfect for what you're looking for (e.g. doesn't account for varying infiltration rates), but it's probably the best you can do with just elevation.  From that, points with high flow accumulation area will approximate the stream network.&lt;/p&gt;&#xA;&lt;p&gt;Searching for that, I didn't find anything that doesn't have any external dependencies, but I did find &lt;a href=&quot;https://vt-hydroinformatics.github.io/rgeoraster.html&quot; rel=&quot;noreferrer&quot;&gt;this guide&lt;/a&gt; entirely within R, which uses the &lt;a href=&quot;https://cran.r-project.org/web/packages/whitebox/index.html&quot; rel=&quot;noreferrer&quot;&gt;R front-end&lt;/a&gt; to &lt;a href=&quot;https://www.whiteboxgeo.com/&quot; rel=&quot;noreferrer&quot;&gt;this open-source geospatial platform, whitebox&lt;/a&gt;.  Installing whitebox is handled entirely through the R library.  Note that the guide is missing a dependency; you have to install and load the &lt;code&gt;rgdal&lt;/code&gt; package too (for visualization).&lt;/p&gt;&#xA;&lt;p&gt;Other than loading &lt;code&gt;rgdal&lt;/code&gt;, I followed those instructions exactly and it seemed to work fine.  The high-accumulation points were a decent approximation of the actual streams in the area.&lt;/p&gt;&#xA;" OwnerUserId="26713" LastActivityDate="2022-04-18T18:13:52.797" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23734" PostTypeId="1" CreationDate="2022-04-19T15:13:47.890" Score="2" ViewCount="78" Body="&lt;p&gt;As I understand, in deep mines on Earth the air pressure increases with depth. At what depth on Mars would the air pressure reach 14psi (97 kPa)?&lt;/p&gt;&#xA;" OwnerUserId="26728" LastEditorUserId="2470" LastEditDate="2022-04-19T16:15:12.643" LastActivityDate="2022-04-20T05:14:32.643" Title="Air pressure on Mars below ground" Tags="|barometric-pressure|mars|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23735" PostTypeId="2" ParentId="23734" CreationDate="2022-04-19T17:27:58.347" Score="1" Body="&lt;p&gt;The &lt;a href=&quot;https://www.grc.nasa.gov/WWW/K-12/rocket/atmosmrm.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mars Atmosphere Model&lt;/a&gt; web page by Nasa lists the equation for atmospheric pressure as,&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$P = 0.699e^{-0.00009h}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where pressure, &lt;span class=&quot;math-container&quot;&gt;$P$&lt;/span&gt; is in kilopascals and &lt;span class=&quot;math-container&quot;&gt;$h$&lt;/span&gt; is height is in meters.&lt;/p&gt;&#xA;&lt;p&gt;Rearranging the equation,&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$h= - \frac{ln(\frac{P}{0.699})}{0.00009}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;For a pressure of 97 kPa,&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$h= - \frac{ln(\frac{97}{0.699})}{0.00009} \ = \ -54\ 809 \ m \ = \ -54.8 \ km$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Which means the atmosphere would need to be 54.8 km below the surface of Mars to have a pressure of 97 kPa.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2022-04-20T05:14:32.643" LastActivityDate="2022-04-20T05:14:32.643" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23736" PostTypeId="1" CreationDate="2022-04-19T19:02:41.720" Score="2" ViewCount="75" Body="&lt;p&gt;How do i get nexrad data from KHGX (Houston)  in 3D to display in matplotlib&lt;/p&gt;&#xA;" OwnerUserId="26704" LastActivityDate="2022-04-19T19:02:41.720" Title="How can i display NEXRAD data in 3d on matplotlib" Tags="|meteorology|python|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23737" PostTypeId="1" CreationDate="2022-04-19T19:07:46.487" Score="4" ViewCount="252" Body="&lt;p&gt;Is it possible to make some generalizations about the hydrographic effects of dredging a channel into an estuary? Or is it too complex a problem and each case must be considered independently?&lt;/p&gt;&#xA;&lt;p&gt;Let me pose a what may be a fairly common scenario: an estuary is connected to the ocean via a channel which allows a reasonable amount of tidal flow - the tide causes currents of 3 to 4 kts in both directions (it is not blocked at any time). The estuary is fed by small creeks but no major river, so the tidal flow is the major influence. There is a proposal to dredge the channel to increase the depth and width to more easily accommodate small vessels.&lt;/p&gt;&#xA;&lt;p&gt;Does dredging change the volume of water that flows through the channel during a tide cycle?&lt;/p&gt;&#xA;&lt;p&gt;If so, does this imply that there is a change in the max and min tide heights in the estuary or is the tidal height unaffected?&lt;/p&gt;&#xA;&lt;p&gt;How does this effect the rate of water flow? (in a simple venturi, it would be slower).&lt;/p&gt;&#xA;&lt;p&gt;What other hydrographic effect might occur? (ignoring biological etc.)&lt;/p&gt;&#xA;" OwnerUserId="26731" LastEditorUserId="2470" LastEditDate="2022-04-20T05:33:53.480" LastActivityDate="2022-04-21T05:15:33.903" Title="Effects of Dredging Estuary Channel on Water Flow" Tags="|oceanography|hydrology|tides|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23738" PostTypeId="1" CreationDate="2022-04-19T19:30:33.617" Score="3" ViewCount="52" Body="&lt;p&gt;I have seen social media-rologists (weather weenies on Twitter) using the Weatherscope app to &lt;a href=&quot;https://i.stack.imgur.com/wlj5a.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;display data from the Canadian radar network&lt;/a&gt;, which was recently upgraded to dual-pol. For many years, NCEI has archived NEXRAD data in GRIB2 format and made it freely accessible to the public. It can be visualized on a computer using the &lt;a href=&quot;https://www.ncdc.noaa.gov/wct/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weather and Climate Toolkit&lt;/a&gt;, or WCT. Does Environment Canada offer the same kind of archived radar data that NCEI does to the public? If not, how does Radarscope gain access to it?&lt;/p&gt;&#xA;" OwnerUserId="6816" LastEditorUserId="6816" LastEditDate="2022-04-19T19:59:00.513" LastActivityDate="2022-04-19T19:59:00.513" Title="Does Environment Canada offer archived radar data in gridded format like in the US?" Tags="|meteorology|radar|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23739" PostTypeId="1" CreationDate="2022-04-19T19:57:39.553" Score="2" ViewCount="510" Body="&lt;p&gt;I am looking for archived model runs for high-resolution North American weather models, i.e. NAM and HRRR stretching back 10+ years. Do these exist on the internet? Failing that, what's the next best thing? Also, how can I transform the numerical data into something that looks as visually appealing as the models on &lt;a href=&quot;https://www.tropicaltidbits.com/analysis/models/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tropical Tidbits?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I'd also like to know if archived models of the &lt;a href=&quot;https://a.atmos.washington.edu/wrfrt/gfsinit.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;GFS-initialized WRF models&lt;/a&gt; or &lt;a href=&quot;https://a.atmos.washington.edu/mm5rt/naminit.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;NAM-initialized MM5 models&lt;/a&gt;, both from the University of Washington's Department of Atmospheric Sciences (basically, PacNW models that reflect the region's microclimates more accurately better than national/global models) are available online.&lt;/p&gt;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="6816" LastActivityDate="2022-09-17T05:02:05.193" Title="Where can I find archived NAM/HRRR model runs?" Tags="|models|weather-forecasting|gfs|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23740" PostTypeId="1" CreationDate="2022-04-19T23:15:42.833" Score="2" ViewCount="174" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/liVhU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/liVhU.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This here is a nice and lovely map of Asia.  Note that the teardrop-shaped Tibetan Plateau dominates the map, and we have India to thank.  For the last 50 million years, it has been pushing upwards, merging into the main continent.  Wherever it touched, the greatest mountain ranges rose up.  Not just the Himalayas, mind you, but others like the Hindu Kush, the Karakoram, Jinping, to name a few.&lt;/p&gt;&#xA;&lt;p&gt;But does the shoving of India to Asia influence the rest of the continent's geography?  &lt;strong&gt;Would the mountain ranges of Turkeye, Iran, Mongolia, China and Siberia exist without India joining Asia, let alone be as big as they are today?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="4985" LastActivityDate="2024-02-13T22:01:55.167" Title="Does the collision of India influence the geology and geography of some of the other mountains of Asia, or just the Himalayas and Tibet?" Tags="|geology|geography|mountains|mountain-building|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23741" PostTypeId="2" ParentId="23739" CreationDate="2022-04-20T04:04:45.547" Score="1" Body="&lt;p&gt;You may be able to find success for the HRRR at either &lt;a href=&quot;https://home.chpc.utah.edu/%7Eu0553130/Brian_Blaylock/cgi-bin/hrrr_download.cgi&quot; rel=&quot;nofollow noreferrer&quot;&gt;CHPC U of Utah&lt;/a&gt; or via &lt;a href=&quot;https://registry.opendata.aws/noaa-hrrr-pds/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Amazon Web Services&lt;/a&gt; (if I remember right, AWS typically has data access charges that you may be able to get around for academic uses, though have never used it).&lt;/p&gt;&#xA;&lt;p&gt;Googling also suggests &lt;a href=&quot;https://www.ready.noaa.gov/archives.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA's Ready archives&lt;/a&gt;, which looks promising for the HRRR and lower resolution NAM.  And &lt;a href=&quot;https://mtarchive.geol.iastate.edu&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iowa State's mtarchive&lt;/a&gt; is often another spot to find some old meteorological data.&lt;/p&gt;&#xA;&lt;p&gt;In terms of how to make it look good, there's a variety of programming languages... GrADS and Gempak are the traditional ones.  Some of the snazzier sites these days were probably done with matplotlib/pylib in Python, or some other tools.  But regardless, any take a fair bit of tweaking to make look good.  Looks like &lt;a href=&quot;https://stackoverflow.com/questions/30571755/how-do-i-plot-gfs-grib2-data-with-python&quot;&gt;this StackOverflow question&lt;/a&gt; covers the topic a small bit, though Googling will likely find you more of what you need.&lt;/p&gt;&#xA;&lt;p&gt;And as for the UW models, you would have to contact them, as it's their product.  IN my experience with other departments running local mesoscale models, they don't generally archive them, as that takes a lot of storage and further work.  There's a link right on the bottom of each page showing the contact is David Ovens at UW with an email link.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2022-04-20T04:04:45.547" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23742" PostTypeId="1" CreationDate="2022-04-20T09:39:30.533" Score="4" ViewCount="84" Body="&lt;p&gt;The island of St Helena in the South Atlantic was volcanically active for 5 million years, or maybe longer. Is this period of time unusual - which other mid-oceanic islands were active for as long as this?&lt;/p&gt;&#xA;" OwnerUserId="12054" LastEditorUserId="2470" LastEditDate="2022-04-20T17:12:25.750" LastActivityDate="2022-04-20T22:53:15.217" Title="For how long can mid-oceanic islands be volcanically active?" Tags="|geology|volcanology|islands|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23743" PostTypeId="1" CreationDate="2022-04-20T16:11:30.003" Score="2" ViewCount="43" Body="&lt;p&gt;Which meteorites in particular give an age of 4.5 billion years and which isotopes are used for radioactive analysis? Is there much variability if different meteorites or isotopes are used?&lt;/p&gt;&#xA;" OwnerUserId="26737" LastActivityDate="2022-04-20T16:11:30.003" Title="Variability in 4.5 billion year age of earth based on radioactive dating of meteorites?" Tags="|earth-history|dating|radioactivity|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23744" PostTypeId="1" AcceptedAnswerId="23771" CreationDate="2022-04-20T19:07:25.950" Score="5" ViewCount="67" Body="&lt;p&gt;I found a formula for the dry deposition speed of particles and an electric circuit analogy to go with it. I would like some clarification on this figure:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aBVbo.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aBVbo.png&quot; alt=&quot;circuit&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I'm mostly interested in the top right circuit. Here, &lt;span class=&quot;math-container&quot;&gt;$R_a$&lt;/span&gt; is the aerodynamic resistance, &lt;span class=&quot;math-container&quot;&gt;$R_{cp}$&lt;/span&gt; is an (effective) canopy resistance and &lt;span class=&quot;math-container&quot;&gt;$V_g$&lt;/span&gt; is the gravitational settling velocity of the particles. I don't understand why there is a &lt;span class=&quot;math-container&quot;&gt;$V_g^{-1}$&lt;/span&gt; in parallel with the other resistors and I'm not sure where the &lt;span class=&quot;math-container&quot;&gt;$R_a R_{cp} V_g$&lt;/span&gt; comes from either. Some hints would be greatly appreciated. I got this figure from &lt;a href=&quot;https://www.researchgate.net/profile/Tilden-Meyers/publication/226641382_A_Preliminary_multiple_resistance_routine_for_deriving_dry_deposition_velocities_from_measured_quantities/links/0c960515ac3abb1ab1000000/A-Preliminary-multiple-resistance-routine-for-deriving-dry-deposition-velocities-from-measured-quantities.pdf&quot; rel=&quot;noreferrer&quot;&gt;Hicks et al. 1987&lt;/a&gt;.&#xA;The final deposition velocity would then be&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$V_d =  (R_a + R_{cp} + R_a R_{cp}V_g)^{-1} + V_g$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;which can easily be derived from the circuit above.&lt;/p&gt;&#xA;" OwnerUserId="22353" LastActivityDate="2022-04-25T12:14:09.323" Title="Clarification of dry deposition of particles" Tags="|atmosphere|atmosphere-modelling|air-pollution|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23745" PostTypeId="2" ParentId="23723" CreationDate="2022-04-20T20:27:53.913" Score="4" Body="&lt;p&gt;One possibility is &lt;a href=&quot;http://www-das.uwyo.edu/%7Egeerts/cwx/notes/chap08/noctilucent.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;nacreous clouds&lt;/a&gt;, very thin clouds likely made of water ice condensed on fine particles carried into the stratosphere. The reported altitude would be at the edge of the range quoted below.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Nacreous clouds, also known as mother-of-pearl clouds, are stratospheric; they occur between 15 and 30 km. Large volcanic eruptions emit dust particles in the lower stratosphere. These may combine with ice to produce nacreous clouds. In fact, in the year following Mt Pinatubo eruption in 1991, many nacreous clouds where spotted by airline pilots flying in the twilight.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The term &amp;quot;nacreous clouds&amp;quot; is often treated as synonymous with &amp;quot;polar stratospheric clouds&amp;quot;, but they can form at non-polar latitudes. Besides volcanic eruptions, they can emerge from upper-air flows over mountains:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;[Nacreous clouds] are most common in two situations. One situation is when strong winds (and winds increasing with height) cross a long mountain ridge, such as the Rocky Mountains in North America. The resulting high-amplitude gravity waves may propagate into the stratosphere. Nacreous clouds there are the stratospheric equivalent to lee wave clouds (Ac lenticularis) in the troposphere.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;And in thunderstorms:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Large thunderstorm systems (mesoscale convective systems, MCSs) may also trigger nacreous clouds. The residual kinetic energy of convective updrafts within MCSs repeatedly poke through the tropopause. The combined effect of these overshooting tops is to bulge the tropopause upwards, and also to diffuse some water vapour in the lower stratosphere. The combination of water vapour transfer and uplift may result in a nacreous cloud above the remnants of an MCS.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;A photograph of nacreous clouds taken by Hans Nilsson of Sweden:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/w6vGv.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/w6vGv.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2022-04-22T12:02:25.237" LastActivityDate="2022-04-22T12:02:25.237" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23746" PostTypeId="1" CreationDate="2022-04-20T22:14:33.170" Score="2" ViewCount="53" Body="&lt;p&gt;So, let's say, ~completely theoretically~ you knew, beyond a reasonable doubt, a large oil company was doing something nefarious near you. They own a &lt;em&gt;very&lt;/em&gt; strange property through a shell company. Now, it's possible that it's just some kind of tax evasion-they claimed it was a &amp;quot;beautification&amp;quot; project after you emailed several people with no response-but all they've done is stack dirt piles very high. This &lt;em&gt;completely theoretical&lt;/em&gt; property also just happens to be completely devoid of plant life, and according to the NPMS there is a pipeline nearby. Would an elevated level of carbon in the soil potentially be indicative of contamination by hydrocarbons? If not, is there any other way to test for this? Sorry if this is the wrong place to post this kind of question, but I couldn't really find anywhere else :)&lt;/p&gt;&#xA;&lt;p&gt;Also, I know it's &lt;em&gt;probably&lt;/em&gt; not an oil spill, but I do have evidence that there's &lt;em&gt;something&lt;/em&gt; going on and I'm just trying to rule this out. Thank you!&lt;/p&gt;&#xA;" OwnerUserId="26739" LastActivityDate="2022-04-21T01:16:04.447" Title="Signs of hydrocarbon contamination in soil?" Tags="|soil|soil-science|hydrocarbons|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23747" PostTypeId="2" ParentId="23742" CreationDate="2022-04-20T22:53:15.217" Score="1" Body="&lt;p&gt;There is a series of volcanic islands in the  Atlantic.&#xA;Besides St. Helena there are for example Bermuda, Madeira, The Canary Islands, Ascension, Tristan da Cunha, The Azores, and Iceland, which is the largest island on the ridge and is active at least for the past 16-18 Ma.&#xA;On St. Helena Abdel-Monem &amp;amp; Gast, (1967) and Baker et al. ( 1967) report  K-Ar ages of 7-14 Ma for the NE and SW volcanoes.&#xA;Data from Chaffey et al. (1989) report  the smaller interval  of 7-9 Ma.&lt;br /&gt;&#xA;An interval of activity of several Ma appears not unusual.&#xA;If hotspot volcanism is the origin, the activity interval is related to the size of island and the relative speed of plate motion across the hotspot.&#xA;A typical speed is 5 mm/a, corresponding to 5km/Ma.&#xA;For an island with 20 km diameter this corresponds to about 4 Ma.&#xA;Again, 5 Ma seems to be a reasonable time interval.&lt;/p&gt;&#xA;" OwnerUserId="26631" LastActivityDate="2022-04-20T22:53:15.217" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23748" PostTypeId="2" ParentId="23746" CreationDate="2022-04-21T01:16:04.447" Score="1" Body="&lt;p&gt;Being devoid of plant life can be due to a number of reasons: purposely sprayed with herbicides, sub soil salt rising to or near the surface or possibly a mass leak of hydrocarbons. Are there any salt scars? Is the ground totally clear of any form of vegetation, including dead plants that once lived there?&lt;/p&gt;&#xA;&lt;p&gt;The other reason for no plant life is the land was purposely cleared using heavy equipment such as bulldozers or graders. The land may have been purposely cleared for other reasons: preparations for drilling of the site, to erect buildings or a similar facility or to accommodate soil heaps, as you have indicated. Do the soil heaps appear to be local soil from the site that has been removed and stockpiled or does it look like soil from elsewhere? How many dumps are there and what would you estimate to be the size of the dumps: length, width and height?&lt;/p&gt;&#xA;&lt;p&gt;Any carbon in the soil could be natural, it could be charcoal that has been plowed in. It is unlikely that any hydrocarbon would have &amp;quot;decomposed/disintegrated&amp;quot; leaving carbon in the ground and hydrogen to escape to the atmosphere. If there were oil related hydrocarbons in the soil and it was in such quantities to kill the vegetation that was there you would possibly be able to smell it from the boundaries of the site. If the land was able to be dug one might be able to smell any liquid hydrocarbons in the soil.&lt;/p&gt;&#xA;&lt;p&gt;As intriguing as your question is, there is not enough detail to give a conclusive answer.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-04-21T01:16:04.447" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23749" PostTypeId="1" CreationDate="2022-04-21T05:05:17.380" Score="4" ViewCount="27" Body="&lt;p&gt;I have two lidar images which I want to use to do a topographic differencing. The two lidar images are of different spatial resolutions and are not co-registered. What is the best method to line the two images up to perform the topographic differencing (by resampling to same the spatial resolution and co-registering the layers)?&lt;/p&gt;&#xA;" OwnerUserId="14152" LastActivityDate="2022-04-21T05:05:17.380" Title="Topographic differencing using lidar" Tags="|topography|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23750" PostTypeId="2" ParentId="23737" CreationDate="2022-04-21T05:15:33.903" Score="4" Body="&lt;p&gt;Although no information is given about the particular estuary that is the subject of this question, considering any estuary in a general manner can provide some conceptual views for clarification of processes.  Generalizations can be made, and with regard to a more detailed understanding of the interactions of inflow and outflow, a simple hydraulic model can be developed.  A recommendation would be to use a simple backwater curve approach for the general dimensions of the inflow/outflow channel of the estuary.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Is it possible to make some generalizations about the hydrographic effects of dredging a channel into an estuary?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Answer: yes.  In general, dredging a channel into an estuary will improve the efficiency of the tidal inflow and receding-tidal outflow from the estuary.  The consequence of this improvement may be undesirable because water residence times within the estuarine environment will be shortened, particularly in the upstream portion above the inflow channel.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Does dredging change the volume of water that flows through the channel during a tide cycle?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Answer:  yes, most likely.  Because dredging will improve the inflow and outflow efficiency of the channel, more water will flow into the upper portion of the estuary.  Under pre-dredging conditions, the channel was less efficient.  Consequently, as high tide was staged, less water would flow into the estuary before high tide started to recede.  Further, as high tide receded, less water would flow out of the estuary before high tide again began to stage. Now, presuming the channel was dredged, under these same tidal conditions more water would flow into the estuary. This is because the inflow channel (being now dredged) would be more efficient in moving water upstream as the channel had been deepened, and perhaps widened, thereby offering less hydraulic resistance to the inflow. And further, the outfall would be more efficient.  Consequently, the interchange of tidal water within the estuary would be increased, which may be undesirable.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;If so, does this imply that there is a change in the max and min tide heights in the estuary or is the tidal height unaffected?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Answer: this depends...  If conditions in the inflow channel offer relatively high resistance to tidal inflow, the upper portion of the estuary may not have come to equilibrium with the elevation of the high tide before the tide begins to recede.  Consequently, the upper area does not reach the full height of the tidal staging. Neither does the upper area fully drain to the stage of the low tide before high tide begins.  Under these natural conditions, specific environments develop within the upper area of the estuary, and in the fore-beach oceanward section of the estuary outfall where the outflow reaches and mixes with the sea.  But if the channel is deepened, less hydraulic resistance to this inflow and outflow is present and the interchange of this water becomes more efficient. The range across the max and min tide heights may be affected.  This can have adverse consequences to the estuarine environment.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;How does this effect the rate of water flow?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Answer:  Dredging will improve the water inflow and thereby increase the rate of inflow and outflow in response to tide.  This is because deepening of the channel reduces the channel's hydraulic resistance and thereby improves (increases) the rate of inflow, and outflow.  Depending on the size of the estuary, and the response to tidal inflow and outflow, the expected consequence would be that somewhat more volume would accrue on the inflow in response to high tide.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;What other hydrographic effect might occur?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Answer:  This is unknown.  In some instances the consequences can be dramatic.  For example, estuarine marshland can be adversely affected by the post-dredging influx of more saline water.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Disclaimer:  This answer is in regard to general observations, only. No consultation or practice liability is assumed.&lt;/p&gt;&#xA;" OwnerUserId="26744" LastActivityDate="2022-04-21T05:15:33.903" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23751" PostTypeId="1" CreationDate="2022-04-21T09:54:29.910" Score="4" ViewCount="113" Body="&lt;p&gt;I have found here an answer that provides formula that only takes into account vapors, pressure and temperature - &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7517/what-is-the-formula-used-for-atmospheric-visibility&quot;&gt;What is the formula used for atmospheric visibility?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Is there an approach that also considers particulate matter and gases concentration? I am actually looking to account for as many contributing factors as possible, to achieve the best estimation, such as hydrometeors density,and whatever else may be related.&lt;/p&gt;&#xA;" OwnerUserId="26745" LastEditorUserId="26745" LastEditDate="2022-04-21T09:59:43.393" LastActivityDate="2022-07-05T19:45:17.673" Title="Estimating meteorological visibility from air chemical and particulate composition" Tags="|meteorology|atmosphere-modelling|air-pollution|atmospheric-dust|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23752" PostTypeId="2" ParentId="23751" CreationDate="2022-04-21T10:51:11.623" Score="4" Body="&lt;p&gt;When you want to take into account as many contributing factors as possible, you will need a complete &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_radiative_transfer_codes&quot; rel=&quot;nofollow noreferrer&quot;&gt;radiative transfer model&lt;/a&gt;, preferably a physics-based one (as opposed to fast radiative transfer models that are often incorporated into weather or climate models).&lt;/p&gt;&#xA;&lt;p&gt;A radiative transfer model takes as input atmospheric composition in one or three dimensions, scattering databases for suspended matter such as aerosols or clouds (if the model includes scattering from particles), a molecular spectroscopic database such as HITRAN, as well as many configuration parameters.  Some models are only valid for certain areas of the atmospheric spectrum.  Some make line-by-line calculations (where &amp;quot;line&amp;quot; here means a location in the spectrum), others make broadband estimates directly.  Examples of well-known line-by-line models that cover visible wavelengths include &lt;a href=&quot;https://en.wikipedia.org/wiki/LBLRTM&quot; rel=&quot;nofollow noreferrer&quot;&gt;LBLRTM&lt;/a&gt; and &lt;a href=&quot;http://www.libradtran.org/doku.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;LibRadtran&lt;/a&gt;. They may not be able to calculate visibility directly, but they should be able to calculate those quantities from which visibility can be estimated.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2022-04-21T13:47:36.607" LastActivityDate="2022-04-21T13:47:36.607" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23753" PostTypeId="1" CreationDate="2022-04-22T11:40:37.343" Score="2" ViewCount="30" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rSlpk.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rSlpk.jpg&quot; alt=&quot;California Geomorphic Provinces&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is the image showing the different geomorphic provinces of California. What led to the formation of these provinces, and what events took place that resulted in the diverse geological setting of California.&lt;/p&gt;&#xA;" OwnerUserId="13748" LastActivityDate="2022-04-22T11:40:37.343" Title="What is the history behind the present day geology of California? What processes took place that led to the formation of each region as shown in fig?" Tags="|geology|tectonics|structural-geology|california|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23754" PostTypeId="1" CreationDate="2022-04-22T14:33:38.107" Score="10" ViewCount="794" Body="&lt;p&gt;I've always described somewhere as &amp;quot;humid&amp;quot; if the air feels very moist and muggy. So, in the US, I'm thinking of places like Texas (e.g., Houston) and Florida (e.g., Miami). I would consider places like California (e.g., LA) and Colorado (pretty much everywhere) as not humid.&lt;/p&gt;&#xA;&lt;p&gt;So I thought maybe humidity is the quantifiable metric for this feeling of mugginess. But then I looked up the average monthly humidity for &lt;a href=&quot;https://weather-and-climate.com/average-monthly-Humidity-perc,Los-Angeles,United-States-of-America&quot; rel=&quot;noreferrer&quot;&gt;https://weather-and-climate.com/average-monthly-Humidity-perc,Los-Angeles,United-States-of-America&lt;/a&gt; vs. &lt;a href=&quot;https://weather-and-climate.com/average-monthly-Rainfall-Temperature-Sunshine,houston,United-States-of-America&quot; rel=&quot;noreferrer&quot;&gt;https://weather-and-climate.com/average-monthly-Rainfall-Temperature-Sunshine,houston,United-States-of-America&lt;/a&gt;, and I was surprised to find that the two were very similar in the summer months, so I'm now confused. I've been to both cities in July, and LA felt very dry, but Houston felt very humid.&lt;/p&gt;&#xA;&lt;p&gt;San Francisco is somewhere I'd consider to not be humid either, and it seems to have about the same humidity levels as Houston year round: &lt;a href=&quot;https://weather-and-climate.com/average-monthly-Rainfall-Temperature-Sunshine,San-Francisco,United-States-of-America&quot; rel=&quot;noreferrer&quot;&gt;https://weather-and-climate.com/average-monthly-Rainfall-Temperature-Sunshine,San-Francisco,United-States-of-America&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So I'm wondering if these humidity measurements is actually representative of the &amp;quot;humid&amp;quot;-ness that I'm feeling when I go to thees places. Should I be looking at other quantifiable metrics?&lt;/p&gt;&#xA;" OwnerUserId="26749" LastActivityDate="2023-05-07T07:43:08.143" Title="Is &quot;humidity&quot; the quantifiable metric for mugginess?" Tags="|humidity|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23755" PostTypeId="2" ParentId="23754" CreationDate="2022-04-22T15:26:01.100" Score="5" Body="&lt;p&gt;There are a number of things going on here.&lt;/p&gt;&#xA;&lt;p&gt;One is microclimate. The data for Houston most likely comes from Houston Intercontinental Airport (IAH), which is 70 miles from the Gulf Coast. Travel ten or twenty miles toward the coast from IAH (and you're not yet in downtown Houston) and you will notice a difference in climate. The data for Los Angeles most likely comes from Los Angeles International Airport (LAX), which is right in the coast. Travel even a few miles inland from LAX and you will notice a huge difference in climate.&lt;/p&gt;&#xA;&lt;p&gt;Another factor is that there is a huge difference between 60% relative humidity, where sweating can still help your body remain cool, and 80% humidity, where sweating starts to fail to function.&lt;/p&gt;&#xA;&lt;p&gt;Yet another factor is temperature. Comfort, or lack thereof, is a combination of temperature and humidity. San Francisco is notoriously humid, but it also has notoriously cool temperatures. &amp;quot;The coldest winter I ever spent was a summer in San Francisco,&amp;quot; supposedly uttered by Samuel Clements, aka Mark Twain.&lt;/p&gt;&#xA;&lt;p&gt;I suggest that you look at dew point rather than humidity regarding comfort level.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-04-22T15:26:01.100" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23756" PostTypeId="2" ParentId="23754" CreationDate="2022-04-22T17:18:00.583" Score="11" Body="&lt;p&gt;Relative humidity is just about the most over-used, relatively useless measure of moisture there is.  It's just how full the air is, based upon what it can hold, in moisture.  Warm air holds more moisture.  So 10° F air with a dew point of 10° F is 100% relative humidity... and 80° F air with a dew point of 75° F is lower relative humidity.  Suffice to say a cold fog in the deep winter feels a lot different... a lot less muggy... than a soupy summer evening in the south.&lt;/p&gt;&#xA;&lt;p&gt;Likewise in terms of weather forecasting, relative humidity doesn't tend to say much.  It can rain and storm strongly with relative humidity very low at ground level, and yet many times won't rain with relative humidity near 100%.  And it's a metric that varies wildly almost daily, basically high at night (when the air is cool and thus nearer full) and low in the daytime (when the air is warm and so can feasibly hold more moisture), despite the level of &lt;em&gt;actual&lt;/em&gt; (absolute) humidity being quite slow to change unless airmasses move in from another area.&lt;/p&gt;&#xA;&lt;p&gt;So use an absolute humidity measure... I prefer the dew point temperature, though other related values like the wet bulb temperature or mixing ratio work as well.  They are often useful in forecasting severe weather or heavy rainfall.  And to me they're good rough indicators of when it feels muggy.  There's still some variation, things like wind and such can still affect how it feels, so perhaps some fancier &lt;a href=&quot;https://earthscience.stackexchange.com/questions/13883/where-can-i-find-the-original-scientific-articles-on-heat-index-published-by-ei&quot;&gt;heat index&lt;/a&gt; or &lt;a href=&quot;https://earthscience.stackexchange.com/questions/19564/how-do-they-determine-the-feels-like-temperatures-for-weather-data/19565#19565&quot;&gt;apparent temperature&lt;/a&gt; may be the most precise.  But it's really up to opinion.  Yet I still think most experts would agree that relative humidity... doesn't really reflect how moist it feels, and doesn't tell us that much about the weather either.  The only thing RH is really helpful with is in fire weather forecasting (plants dry out in low relative humidity and high winds)... but I believe the vast majority of people get nothing useful out of the relative humidity, when instead they could get something better from something like the dew point, if we'd just opt to more actively present it to the public.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2023-05-07T07:43:08.143" LastActivityDate="2023-05-07T07:43:08.143" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="23757" PostTypeId="1" CreationDate="2022-04-22T20:29:06.183" Score="4" ViewCount="355" Body="&lt;p&gt;I was reading on fossilization and I came across petrifaction. Are fossils that take the shape (have the shape) of the original organism made of only stone or iron? Can there be a fossil made of any other substance?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Petrifaction&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; mentions stone/iron fossils:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The minerals commonly involved in replacement are calcite, silica, pyrite, and hematite.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Are all minerals involved in &amp;quot;replacement&amp;quot; a stone/iron material, or are other materials ever involved in this process?&lt;/p&gt;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="26750" LastEditorUserId="2958" LastEditDate="2022-04-26T07:46:35.847" LastActivityDate="2022-04-26T07:46:35.847" Title="What materials are fossils made of?" Tags="|paleontology|fossils|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23758" PostTypeId="1" CreationDate="2022-04-22T21:28:17.347" Score="2" ViewCount="1165" Body="&lt;p&gt;I am reading on the petrification process. I found that there are two processes which are permineralization and replacement. I am not sure I fully comprehend the difference between them. I wonder if someone could explain them to me in simple terms.&lt;/p&gt;&#xA;&lt;p&gt;Am I right to understand that permineralization is where the minerals replace the space where the bones of animal (for examples) reside making a cast of what the organism looks like while replacement replaces the bones of that animal on a molecular level where each molecule of the the organism's bones are replacement by a molecule from the mineral i.e. the replacement process is transforming/converting the bones into another substance. Also do the molecules of bones cease to exist after they are replaced?&lt;/p&gt;&#xA;&lt;p&gt;Thanks for your time.&lt;/p&gt;&#xA;" OwnerUserId="26750" LastEditorUserId="26750" LastEditDate="2022-04-22T22:03:35.593" LastActivityDate="2022-04-24T09:00:42.537" Title="What is the difference between permineralization and replacement" Tags="|paleontology|fossils|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23760" PostTypeId="2" ParentId="23758" CreationDate="2022-04-23T23:11:25.430" Score="2" Body="&lt;p&gt;Simply put permineralization is dissolved minerals filling in the existing pore space in fossilized material. Replacement is dissolved minerals replacing the existing minerals (calcium phosphate, calcium carbonate, etc.) in fossil material via atom by atom or molecule by molecule ion exchange. Often both can occur but permineralization can leave original material in the fossil while replacement does not.&lt;/p&gt;&#xA;&lt;p&gt;Replacement can happen after permineralization, in which case most of the structure gets preserved (but not material) even though replacement occurs.&lt;/p&gt;&#xA;&lt;p&gt;Keep in mind once the living cells are dead bone, wood, and even shell is full of tiny pores and holes that can get filled in. Think of a sponge, in permineralization the sponge gets filled in with stuff, in replacement the sponge slowly dissolves but gets replaced by something else dissolved in the water as it leaves charges behind.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="2470" LastEditDate="2022-04-24T09:00:42.537" LastActivityDate="2022-04-24T09:00:42.537" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23761" PostTypeId="2" ParentId="23723" CreationDate="2022-04-24T07:50:26.887" Score="-1" Body="&lt;p&gt;Polar stratospheric clouds occur at same level as Ozone layer.&#xA;Otherwise known as Nacreous clouds.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/5sYPk.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5sYPk.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2022-04-24T07:50:26.887" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23762" PostTypeId="1" CreationDate="2022-04-24T13:53:32.137" Score="6" ViewCount="5717" Body="&lt;p&gt;The circumference of the Earth has been measured to be &lt;span class=&quot;math-container&quot;&gt;$40,075 \,\pu{km}$&lt;/span&gt;, which is only &lt;span class=&quot;math-container&quot;&gt;$21 \,\pu{km}$&lt;/span&gt; from &lt;span class=&quot;math-container&quot;&gt;$40,096 = 2^{12}$&lt;/span&gt;. For reference, &lt;span class=&quot;math-container&quot;&gt;$40,075 \approx 2^{11.992}$&lt;/span&gt;. This is probably a strange coincidence, but originally a meter was set to be &lt;span class=&quot;math-container&quot;&gt;$1/10,000,000$&lt;/span&gt;-th of the distance from the North Pole to the Equator, so maybe there is a mathematical explanation.&lt;/p&gt;&#xA;" OwnerUserId="26755" LastEditorUserId="2470" LastEditDate="2022-04-26T18:24:59.217" LastActivityDate="2022-04-26T18:24:59.217" Title="Is it a coincidence that the circumference of the Earth in kilometers is almost $2^{12}$?" Tags="|geodesy|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23764" PostTypeId="2" ParentId="23762" CreationDate="2022-04-24T17:38:09.160" Score="12" Body="&lt;p&gt;There's something wrong with your math, &lt;span class=&quot;math-container&quot;&gt;$2^{12} \ = \ 4096$&lt;/span&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$2^x \ = \ 40\ 000$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\therefore x\log2 \ = \ \log\ 40\ 000$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\therefore x \ = \ \frac{\log\ 40000}{\log\ 2}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\therefore x \ = \ 15.28771$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Thus, &lt;span class=&quot;math-container&quot;&gt;$2^{15.28771} \ = \ 40\ 000$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="10831" LastEditDate="2022-04-25T09:41:35.140" LastActivityDate="2022-04-25T09:41:35.140" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23765" PostTypeId="2" ParentId="23762" CreationDate="2022-04-24T18:08:51.280" Score="37" Body="&lt;p&gt;Well, as others have pointed out we're a little off from &lt;span class=&quot;math-container&quot;&gt;$2^{12}$&lt;/span&gt; kilometers. However, there is no coincidence that our world's circumference is close to &lt;span class=&quot;math-container&quot;&gt;$40000$&lt;/span&gt; kilometers. From &lt;a href=&quot;https://en.wikipedia.org/wiki/Metre&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The metre was originally defined in 1793 as one ten-millionth of the distance from the equator to the North Pole along a great circle, so the Earth's circumference is approximately 40000 km.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2022-04-24T18:08:51.280" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23766" PostTypeId="1" CreationDate="2022-04-24T23:31:14.070" Score="5" ViewCount="71" Body="&lt;p&gt;When and how did mosquitoes reach Australia?&lt;/p&gt;&#xA;&lt;p&gt;It's east of the Wallace line, so 'they got there from Asia' is not an obviously unproblematic conclusion.&lt;/p&gt;&#xA;&lt;p&gt;In general, when and how mosquitoes reached remote Pacific islands is a nontrivial question. For example, Hawaii was free of them until historically recent time when they stowed away on a ship.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sydney.edu.au/news-opinion/news/2013/07/24/study-finds-introduced-mosquito-species-active-all-year-round.html&quot; rel=&quot;noreferrer&quot;&gt;Study finds introduced mosquito species active all year round&lt;/a&gt; suggests one particular mosquito species only reached Australia during World War II, but also says&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Australia has plenty of 'home grown' mosquitoes&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Which indicates that other species have been there much longer.&lt;/p&gt;&#xA;&lt;p&gt;Did they reach Australia at the same time as the marsupials, tens of millions of years ago when the continent was closer to Asia?&lt;/p&gt;&#xA;" OwnerUserId="7911" LastEditorUserId="18088" LastEditDate="2022-04-25T03:44:22.277" LastActivityDate="2022-04-25T03:44:22.277" Title="When did mosquitoes reach Australia?" Tags="|earth-history|paleontology|ecology|geobiology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23767" PostTypeId="1" CreationDate="2022-04-24T23:53:58.850" Score="2" ViewCount="21" Body="&lt;p&gt;Phys.org's April 23, 2022 &lt;a href=&quot;https://phys.org/news/2022-04-largest-marsquakes-date-planet-side.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Two largest marsquakes to date recorded from planet's far side&lt;/a&gt; links to &lt;a href=&quot;https://pubs.geoscienceworld.org/ssa/tsr/article/2/2/88/613226/The-Far-Side-of-Mars-Two-Distant-Marsquakes&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Far Side of Mars: Two Distant Marsquakes Detected by InSight&lt;/a&gt; which contains the image below.&lt;/p&gt;&#xA;&lt;p&gt;Answers to &lt;a href=&quot;https://space.stackexchange.com/q/40505/12102&quot;&gt;How are marsquake epicenters determined using only one seismometer?&lt;/a&gt; tell us that the presence of both s and p waves and their different propagation speeds helps.&lt;/p&gt;&#xA;&lt;p&gt;But in the case of these to well publicized and studied events I'd like to ask more specifically:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; How well can they localize the sources of these marsquakes using only a single seismometer? Does being in the shadow zone of the core help or hinder?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/39dnB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/39dnB.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Figure 1. Summary of Martian interior models from Stähler et al. (2021)&#xA;and ray paths for seismic phases from events presented in this article.&#xA;(a) The travel time curves are computed using the TauP package (Crotwell&#xA;et al., 1999) for a source depth of 50 km. The phase picks that the&#xA;Marsquake Service (MQS) identified for these events are indicated with&#xA;crosses, with varying symbol sizes to schematically reflect the pick&#xA;uncertainties. The distant events are S1000a and S0976a. For comparison, also shown is S0173a, an event at 30° that locates at Cerberus&#xA;Fossae. For all three events, high-amplitude phase arrivals have been&#xA;identified as direct P/S for S0173a and single free-surface reflections PP/SS&#xA;for S1000a and S0976a. For S1000a, a weak Pdiff phase that is diffracted&#xA;along the core–mantle boundary is also identified. The vertical dashed&#xA;lines and gray shaded bars mark the event distances and uncertainties&#xA;from Table S1, respectively. (b) The structural models are not constrained&#xA;by observations for depths below ∼800 km for P waves (hatched region;&#xA;Khan et al., 2021), hence the Pdiff travel times are purely from model&#xA;predictions. (c) Illustrates the ray paths of the identified phases using a&#xA;Mars model with a core radius of 1855 km.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Related and potentially helpful in Earth Science SE:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/q/16510/6031&quot;&gt;What could be causing microseisms on Mars?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;and in Space Exploration SE:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://space.stackexchange.com/q/34022/12102&quot;&gt;Just how sensitive is the Insight seismometer?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://space.stackexchange.com/q/34538/12102&quot;&gt;What is VBB recentering (InSight lander's Very Broad Band seismic pendulums)?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://space.stackexchange.com/q/36032/12102&quot;&gt;How are the most sensitive seismometers on Mars protected from the most powerful jackhammer on Mars just a few feet away?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://space.stackexchange.com/q/32694/12102&quot;&gt;What are InSight's barometric and seismic digitization rates and frequency responses when it &amp;quot;listens to the wind&amp;quot;?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://space.stackexchange.com/q/52337/12102&quot;&gt;Plot of the thermally-induced tilt in Martian surface during solar eclipse by Phobos? (slope of 1 atom per meter?)&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://space.stackexchange.com/q/38543/12102&quot;&gt;Has Mars quaked yet? Any scientific speculation when it might?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://space.stackexchange.com/q/32268/12102&quot;&gt;How was InSight's vertical seismometer (accelerometer) tested in Earth's stronger gravity?&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2022-04-24T23:53:58.850" Title="How well can they localize the sources of these marsquakes using only a single seismometer? Does being in the shadow zone of the core help or hinder?" Tags="|seismology|data-analysis|mars|instrumentation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23768" PostTypeId="1" CreationDate="2022-04-25T01:51:53.600" Score="1" ViewCount="346" Body="&lt;p&gt;So I'm trying to create  dropdown menu that loads different goes satellite data but when i embed the code to my code nothing displays but it displays perfectly on Notebook and yes i am using Visual studio code&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import cartopy.crs as ccrs&#xA;import cartopy.feature as cfeature&#xA;from IPython.display import display&#xA;from ipywidgets import Dropdown, interact, fixed, Select&#xA;from matplotlib import patheffects&#xA;import matplotlib.pyplot as plt&#xA;import metpy&#xA;from metpy.plots import add_timestamp&#xA;import numpy as np&#xA;from siphon.catalog import TDSCatalog&#xA;def open_dataset(date, channel, idx, region):&#xA;    &amp;quot;&amp;quot;&amp;quot;&#xA;    Open and return a netCDF Dataset object for a given date, channel, and image index&#xA;    of GOES-16 data from THREDDS test server.&#xA;    &amp;quot;&amp;quot;&amp;quot;&#xA;    cat = TDSCatalog('https://thredds.ucar.edu/thredds/catalog/satellite/goes/east/products/'&#xA;                     f'CloudAndMoistureImagery/{region}/Channel{channel:02d}/{date:%Y%m%d}/catalog.xml')&#xA;    ds = cat.datasets[idx]&#xA;    ds = ds.remote_access(use_xarray=True)   &#xA;    return ds&#xA;def plot_GOES16_channel(date, idx, channel, region):&#xA;    &amp;quot;&amp;quot;&amp;quot;&#xA;    Get and plot a GOES 16 data band from the ABI.&#xA;    &amp;quot;&amp;quot;&amp;quot;&#xA;    ds = open_dataset(date, channel, idx, region)&#xA;    dat = ds.metpy.parse_cf('Sectorized_CMI')&#xA;    proj = dat.metpy.cartopy_crs&#xA;    x = dat['x']&#xA;    y = dat['y']&#xA;&#xA;    fig = plt.figure(figsize=(10, 10))&#xA;    ax = fig.add_subplot(1, 1, 1, projection=proj)&#xA;    ax.add_feature(cfeature.COASTLINE, linewidth=2)&#xA;    ax.add_feature(cfeature.STATES, linestyle=':', edgecolor='black')&#xA;    ax.add_feature(cfeature.BORDERS, linewidth=2, edgecolor='black')&#xA;&#xA;    for im in ax.images:&#xA;        im.remove()&#xA;    im = ax.imshow(dat, extent=(x.min(), x.max(), y.min(), y.max()), origin='upper')&#xA;    timestamp = datetime.strptime(ds.start_date_time, '%Y%j%H%M%S')&#xA;    &#xA;    add_timestamp(ax, time=timestamp, high_contrast=True, &#xA;                  pretext=f'GOES 16 Ch.{channel} - ',&#xA;                  time_format='%d %B %Y %H%MZ', y=0.01,&#xA;                  fontsize=18)&#xA;    display(fig)&#xA;    plt.close()&#xA;channel_list = {u'1 - Blue Band 0.47 \u03BCm': 1,&#xA;                u'2 - Red Band 0.64 \u03BCm': 2,&#xA;                u'3 - Veggie Band 0.86 \u03BCm': 3,&#xA;                u'4 - Cirrus Band 1.37 \u03BCm': 4,&#xA;                u'5 - Snow/Ice Band 1.6 \u03BCm': 5,&#xA;                u'6 - Cloud Particle Size Band 2.2 \u03BCm': 6,&#xA;                u'7 - Shortwave Window Band 3.9 \u03BCm': 7,&#xA;                u'8 - Upper-Level Tropo. WV Band 6.2 \u03BCm': 8,&#xA;                u'9 - Mid-Level Tropo. WV Band 6.9 \u03BCm': 9,&#xA;                u'10 - Low-Level WV Band 7.3 \u03BCm': 10,&#xA;                u'11 - Cloud-Top Phase Band 8.4 \u03BCm': 11,&#xA;                u'12 - Ozone Band 9.6 \u03BCm': 12,&#xA;                u'13 - Clean IR Longwave Band 10.3 \u03BCm': 13,&#xA;                u'14 - IR Longwave Band 11.2 \u03BCm': 14,&#xA;                u'15 - Dirty Longwave Band 12.3 \u03BCm': 15,&#xA;                u'16 - CO2 Longwave IR 13.3 \u03BCm': 16}&#xA;&#xA;region = Select(&#xA;    options=['Mesoscale-1', 'Mesoscale-2', 'CONUS', 'PuertoRico', 'FullDisk'],&#xA;    description='Region:',&#xA;)&#xA;&#xA;channel = Dropdown(&#xA;    options=channel_list,&#xA;    value=9,&#xA;    description='Channel:',&#xA;)&#xA;&#xA;date = datetime.utcnow()&#xA;interact(plot_GOES16_channel, date=fixed(date), idx=fixed(-2), &#xA;         channel=channel, region=region)```&#xA;&#xA;  &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="26704" LastActivityDate="2022-04-25T01:53:14.430" Title="I'm trying to create a interactive matplotlib figure with a dropdown menu on a tkinter popup window but nothing displays" Tags="|meteorology|python|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23770" PostTypeId="1" AcceptedAnswerId="23779" CreationDate="2022-04-25T10:51:43.590" Score="4" ViewCount="65" Body="&lt;p&gt;I just came across &lt;a href=&quot;https://skeptics.stackexchange.com/questions/53234/sailing-from-north-east-russia-to-pakistan-in-a-straight-line#53234&quot;&gt;a question on skeptics.SE&lt;/a&gt; that asked whether it is possible to sail a boat from the coast of Pakistan to the east coast of Russia in an uninterrupted straight line. A quick glance at a globe suggests that there's nothing to be really skeptical about (the OP may have been misled by the planar nature of map projections). But while thinking about the question, I realized that I don't know the right terminology to describe the changes to the bearing on board of the ship.&lt;/p&gt;&#xA;&lt;p&gt;As a rough estimate, a ship sailing from Karachi to the Kamchatka Peninsula will start with a bearing of perhaps 210° (relative to true north). If it continues its course in a straight line, it will be sailing basically parallel to the meridians with a bearing of 270° roughly by the time the ship has reached the South Sandwich Islands. The bearing at the Equator will be somewhere in the vicinity of 330°, and it will arrive at Kamchatka with a bearing of about 290°.&lt;/p&gt;&#xA;&lt;p&gt;What is the right term to refer to this phenomenon that the true bearing changes if you move in a straight line in a non-cardinal direction on a globe? I keep thinking of &amp;quot;declination&amp;quot;, but this is probably because I'm aware of what magnetic declination is.&lt;/p&gt;&#xA;" OwnerUserId="15165" LastEditorUserId="15165" LastEditDate="2022-04-25T11:01:12.923" LastActivityDate="2022-04-30T17:06:31.733" Title="What is the right term to describe the observation that your true bearing changes if you move in a non-cardinal direction on a globe?" Tags="|terminology|geodesy|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23771" PostTypeId="2" ParentId="23744" CreationDate="2022-04-25T12:14:09.323" Score="4" Body="&lt;p&gt;I'm not sure if you've gone one citation deeper into the report,&lt;/p&gt;&#xA;&lt;p&gt;Hicks et al (1985) &lt;em&gt;On the Use of Monitored Air Concentrations to Infer Dry Deposition&lt;/em&gt;, NOAA Technical Memorandum ERLO ARLZ141 (&lt;a href=&quot;https://repository.library.noaa.gov/view/noaa/19701&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://repository.library.noaa.gov/view/noaa/19701&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;where there's more information in Appendix C on the origin of those diagrams.&lt;/p&gt;&#xA;&lt;p&gt;They make the argument that the turbulent and gravitational (settling) deposition fluxes are separable and additive such that the total deposition velocity is,&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$v_p = v_d + v_g = -F_p / C$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$F_p$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; are the particle flux and concentration, respectively. They then note that,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This simple procedure introduces a conceptual problem, however, since obviously both &lt;span class=&quot;math-container&quot;&gt;$v_d$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; are functions of height and &lt;span class=&quot;math-container&quot;&gt;$v_g$&lt;/span&gt; is not.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;at which point they assume two equations for &lt;span class=&quot;math-container&quot;&gt;$F_p$&lt;/span&gt; (Eqns. C5 and C6), one for the turbulent layer and one for the canopy layer:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;F_p = - \left[C(z) - C(z_0)\right] \,r_a^{-1} - C(z) \, v_g\\&#xA;F_p = -C(z_0) \, r_{cp}^{-1} - C(z_0)\, v_g&#xA;$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;These can be combined to eliminate &lt;span class=&quot;math-container&quot;&gt;$C(z_0)$&lt;/span&gt;, and the result combined with the &lt;span class=&quot;math-container&quot;&gt;$v_p$&lt;/span&gt; equation above and rearranged to yield Eq C7,&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$v_p = (r_a + r_{cp} + r_a r_{cp} v_g)^{-1} + v_g$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The circuit diagram you show in the top right is an expression of this equation, which shows how the traditional circuit diagram can be modified to account for turbulent transfer in the presence of gravitational settling.  They note, however, that,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In practice, the triple-product term in Equation (C.7) is unlikely to be of great significance unless &lt;span class=&quot;math-container&quot;&gt;$v_g$&lt;/span&gt; is relatively large. Detailed consideration of the ramifications is not warranted, since great uncertainty surrounds the quantity &lt;span class=&quot;math-container&quot;&gt;$r_{cp}$&lt;/span&gt; for the case of particles.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="106" LastActivityDate="2022-04-25T12:14:09.323" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23772" PostTypeId="1" CreationDate="2022-04-25T13:18:37.257" Score="1" ViewCount="35" Body="&lt;p&gt;I have a dataset that gives values of&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;temperature,&lt;/li&gt;&#xA;&lt;li&gt;Relative humidity&lt;/li&gt;&#xA;&lt;li&gt;Geopotential&lt;/li&gt;&#xA;&lt;li&gt;Ozone mass mixing ratio&lt;/li&gt;&#xA;&lt;li&gt;Potential vorticity&lt;/li&gt;&#xA;&lt;li&gt;Fraction of cloud cover&lt;/li&gt;&#xA;&lt;li&gt;Specific cloud ice water content&lt;/li&gt;&#xA;&lt;li&gt;Specific cloud&lt;/li&gt;&#xA;&lt;li&gt;liquid water content&lt;/li&gt;&#xA;&lt;li&gt;Specific humidity&lt;/li&gt;&#xA;&lt;li&gt;Specific rainwater content&lt;/li&gt;&#xA;&lt;li&gt;Specific snow water content&lt;/li&gt;&#xA;&lt;li&gt;Divergence&lt;/li&gt;&#xA;&lt;li&gt;U-component of wind&lt;/li&gt;&#xA;&lt;li&gt;V-component of wind.&lt;/li&gt;&#xA;&lt;li&gt;Vertical velocity&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;which parameters will make sense to do regression for electricity consumption? In search of this, I got this paper, &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0306261914005674&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/S0306261914005674&lt;/a&gt; which use temperature and relative humidity for the same, and there are other papers also which uses temperature only as a parameter. Do you think that any other parameter from above I should incorporate? Can anyone please give an answer to the above question and pointwise reasoning for each item parameter and why it is used to calculate electricity consumption?&lt;/p&gt;&#xA;" OwnerUserId="26761" LastActivityDate="2022-04-25T13:18:37.257" Title="Which atmospheric parameters will give accurate result of electricity consumption of an area by using multiple regression model?" Tags="|meteorology|temperature|data-analysis|python|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23773" PostTypeId="2" ParentId="23757" CreationDate="2022-04-25T23:52:30.067" Score="2" Body="&lt;p&gt;Fossilization can occur using literally any mineral that is water soluble, which nearly all of them are. The problem you are running into is &amp;quot;fossil&amp;quot; covers a huge range of things, from insects in amber to shell casts, to permineralized dinosaur bones, the chemistry of the processes therefore also cover a huge range of things and will require quite a solid understanding of geochemistry. Worse, the early stages of fossilization are not well understood. By its nature, figuring out what is and is not in the process of becoming a fossil is difficult, so there are several competing ideas and all of them might well be true.&lt;/p&gt;&#xA;&lt;p&gt;A few quick definitions.&lt;/p&gt;&#xA;&lt;p&gt;Stone is any solid composed of nonliving material with a fairly well defined chemical composition, stone is one of the broadest definitions in science.&lt;/p&gt;&#xA;&lt;p&gt;There is a free textbook on paleontology online, that should be a good spot to get started.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;a href=&quot;https://www.a-centauri.com/archivio/geo/Paleontologia/Benton_Introduction%20to%20Paleobiology%20and%20the%20Fossil%20Record.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Introduction to Paleobiology and the Fossil Record&lt;/a&gt;&lt;/em&gt;, Michael J Benton and David A. T. Harper, Wiley-Blackwell.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="2470" LastEditDate="2022-04-26T00:47:01.613" LastActivityDate="2022-04-26T00:47:01.613" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23774" PostTypeId="2" ParentId="2830" CreationDate="2022-04-26T17:55:32.747" Score="1" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Clair_Cameron_Patterson&quot; rel=&quot;nofollow noreferrer&quot;&gt;Patterson&lt;/a&gt; could not age the Earth from Uranium to lead decay root because the Zircon samples were contaminated by &lt;a href=&quot;https://en.wikipedia.org/wiki/Clair_Cameron_Patterson#Measurement_of_age_of_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;lead pollution&lt;/a&gt; at that time. So he used meteorites under the assumption that they were formed approximately the same period as our planet thus 4.55 billion years ago.&lt;/p&gt;&#xA;" OwnerUserId="26772" LastActivityDate="2022-04-26T17:55:32.747" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23776" PostTypeId="1" CreationDate="2022-04-27T06:03:14.237" Score="1" ViewCount="36" Body="&lt;p&gt;We have uneven terrain (street) and want to distribute water fairly equally to all locations (homes). The issue is that the locations at the end get sufficient water and other locations need to wait.&lt;/p&gt;&#xA;&lt;p&gt;The water supply is not metered, so is there any other way we can fix this issue so every location gets an equal amount of water?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oajer.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oajer.png&quot; alt=&quot;Locations at the end get more water than others&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26774" LastActivityDate="2022-04-27T06:03:14.237" Title="How to maintain average elevation of water on uneven terrain?" Tags="|water|" AnswerCount="0" CommentCount="3" ClosedDate="2022-04-29T17:50:55.637" ContentLicense="CC BY-SA 4.0" />
  <row Id="23777" PostTypeId="1" CreationDate="2022-04-27T08:24:11.120" Score="2" ViewCount="219" Body="&lt;p&gt;On which time scale is the carbon stored in petroleum and black coal released back to the atmosphere under natural conditions? Exploiting fossil fuels and burning them releases the carbon today, but when would it have been released under natural conditions? Which processses does the coal go through on the carbon's long way back to atmosphere?&lt;/p&gt;&#xA;&lt;p&gt;I have no idea of the orders of magnitude. Is it millions or billions of years? Being bound forever cannot be true, because nothing remains forever.&lt;/p&gt;&#xA;&lt;p&gt;Primo Levi's chapter on &lt;a href=&quot;https://www.arvindguptatoys.com/arvindgupta/periodic-primo.pdf#page=227&quot; rel=&quot;nofollow noreferrer&quot;&gt;Carbon&lt;/a&gt; didn't give me the answers I am looking for.&lt;/p&gt;&#xA;&lt;p&gt;On the German Wikipedia page on the &lt;a href=&quot;https://de-m-wikipedia-org.translate.goog/wiki/Kreislauf_der_Gesteine?_x_tr_sl=de&amp;amp;_x_tr_tl=en&amp;amp;_x_tr_hl=de&amp;amp;_x_tr_pto=wapp&quot; rel=&quot;nofollow noreferrer&quot;&gt;rock cycle&lt;/a&gt;, I read that the typical rock cycle takes approx. 200 million years. Is this the number I am looking for? Is this number reliable?&lt;/p&gt;&#xA;" OwnerUserId="17431" LastEditorUserId="17431" LastEditDate="2022-04-27T09:12:34.960" LastActivityDate="2022-04-27T10:21:43.620" Title="When is the carbon stored in fossil fuels released back to the atmosphere under natural conditions?" Tags="|carbon-cycle|carbon|fossil-fuel|coal|oil-reserves|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23778" PostTypeId="2" ParentId="23777" CreationDate="2022-04-27T10:21:43.620" Score="2" Body="&lt;p&gt;What natural processes do you contemplate would result in fossilized carbon (coal, oil or gas) being returned to the atmosphere?&lt;/p&gt;&#xA;&lt;p&gt;Judging from the &lt;a href=&quot;https://www.sciencedirect.com/topics/engineering/coal-deposits&quot; rel=&quot;nofollow noreferrer&quot;&gt;picture below&lt;/a&gt;,&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CFW1j.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CFW1j.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Some coal deposits are between 250 Ma &amp;amp; 325 Ma old. So this destroys the idea of 200 million year old rock cycle affecting fossilized carbon deposits. These deposits not being naturally depleted and won't be for a very long time, if ever.&lt;/p&gt;&#xA;&lt;p&gt;Some of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Oldest_dated_rocks&quot; rel=&quot;nofollow noreferrer&quot;&gt;oldest rock formations&lt;/a&gt; on Earth date back 3.8 Ga. Some parts of the world are geologically very inactive.&lt;/p&gt;&#xA;&lt;p&gt;Some fossilized carbon may be returned to the atmosphere if they get caught up in a subduction trench.&lt;/p&gt;&#xA;&lt;p&gt;Looking at the picture below, of the known coal deposits, globally, the deposits in Australia are possibly the most stable. Australia is in the middle of a &lt;a href=&quot;https://en.wikipedia.org/wiki/Plate_tectonics&quot; rel=&quot;nofollow noreferrer&quot;&gt;tectonic plate&lt;/a&gt; &amp;amp; its coal &amp;amp; gas deposits are far from subduction zones. Similarly the deposits on the Eurasian land mass are also on very stable tectonic regions .&lt;/p&gt;&#xA;&lt;p&gt;New Zealand and Indonesia are on the boundary of an active tectonic regions &amp;amp; their coal deposits might be affected by volcanic activity. Likewise some of the coal deposits of eastern Africa might be affected volcanic and tectonic activity associated with the &lt;a href=&quot;https://en.wikipedia.org/wiki/East_African_Rift&quot; rel=&quot;nofollow noreferrer&quot;&gt;East African Rift&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZfoDf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZfoDf.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, some coal seams that outcrop on the surface may be ignited by lightening that could result in a slow underground fire the burns for a long time. The oldest known &lt;a href=&quot;https://en.wikipedia.org/wiki/Coal-seam_fire&quot; rel=&quot;nofollow noreferrer&quot;&gt;underground coal fire&lt;/a&gt; is Australia's burning mountain. It is estimated to have been burning for 6000 years.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-04-27T10:21:43.620" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23779" PostTypeId="2" ParentId="23770" CreationDate="2022-04-28T11:14:14.373" Score="2" Body="&lt;p&gt;I would refer to it as &amp;quot;geodesic curvature&amp;quot;, because this is exactly what happens. On a sphere all distinct geodesics curve everywhere towards each other except for perpendicular pairs. That includes curving towards the Equator except for the Equator itself (meaning not a distinct geodesic) or a meridian (perpendicular to the Equator). Curving towards the Equator is then what registers as the change in bearing.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2022-04-28T11:14:14.373" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23780" PostTypeId="1" CreationDate="2022-04-29T01:44:21.040" Score="5" ViewCount="705" Body="&lt;p&gt;I'd like to know how the state-of-the-art meteorological direct, localized measurements of the temperature of the air is measured.&lt;/p&gt;&#xA;&lt;p&gt;If you put a thermometer in sunlight it may read high. If you put it in a box with some air vents it may also read high during the day and exhibit a time lag due to local trapping of air when there's no wind and due to radiation exchange with the thermal cavity in which it now sits.&lt;/p&gt;&#xA;&lt;p&gt;If there's suspended droplets of water in the air it can condense or simply collect on surfaces and later evaporate which can act as a source or sink of heat with the thermometer.&lt;/p&gt;&#xA;&lt;p&gt;The rate of heat exchange between the air and the thermometer is pretty low due to the relatively low density of air, so these other effects can significantly compete.&lt;/p&gt;&#xA;&lt;p&gt;So I'd like to ask:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; How do meteorologists accurately measure outdoor air temperature?&lt;/p&gt;&#xA;&lt;p&gt;Of course there are other ways to determine the average temperature of a geographically large amount of air of some significant thickness in height, but I'm asking about localized measurements at say a meteorological data collection station at an airport or other fixed site, collecting data for archival purposes or weather predictions, or even air temperature measurements from a system affixed to a weather balloon or aircraft used to collect data.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2022-05-05T17:53:10.457" Title="How do meteorologists accurately measure outdoor air temperature? There's sunlight, local trapping of air, radiant heat, precipitation" Tags="|meteorology|atmosphere|instrumentation|air|" AnswerCount="1" CommentCount="16" ContentLicense="CC BY-SA 4.0" />
  <row Id="23781" PostTypeId="1" CreationDate="2022-04-29T18:16:11.843" Score="4" ViewCount="205" Body="&lt;p&gt;&lt;strong&gt;Background&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I read (what I could understand of) &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020GL088303&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; in which authors Yuan and Steinle-Neumann &amp;quot;...use advanced quantum mechanical simulations on silicate and metallic melts showing that hydrogen becomes increasingly more incorporated in metal over silicate at high pressure and temperature, conditions under which Earth's core formed. Therefore, hydrogen can be present in the core in high abundance. [...] The Earth's early accretion events, in particular magma ocean formation, had a great impact on the chemical and thermal evolution of the Earth. Segregation of metal from silicate to form a core during the magma ocean stage has removed elements besides iron and nickel from the mantle[...]. Light elements such as H, C, O, and Si enter the core as a consequence of this process.&amp;quot; The article goes on to present a model for how light elements near the planet's surface could end up being transported to the core, leaving a mostly silicate crust with both light elements and metals mostly transported down to the core: light elements form weak bonds with iron under high pressures and are gravitationally sorted with the iron. &amp;quot;We find that hydrogen is weakly siderophile at low pressure (20 GPa and 2,500 K), and becomes much more strongly so with pressure, suggesting that hydrogen is transported to the core in a significant amount during core segregation and is stable there.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;How did diffuse hydrogen in the near-vacuum of the planetary accretion disk find itself bound, chemically or gravitationally, to the forming Earth in the first place?&lt;/p&gt;&#xA;&lt;p&gt;As I understand it, the mechanism proposed for incorporation into the core necessitates extreme pressures and temperatures - which is good for explaining how it got from deep in the molten surface down to the core, but doesn't seem to fit planet formation in the first place. Why didn't the hydrogen swept out by proto-Earth simply boil off of the upper atmosphere as fast as it came in, never finding itself in a pressure regime sufficient to become chemically bound to iron?&lt;/p&gt;&#xA;&lt;p&gt;It seems to me that intermediate chemical bonding of hydrogen into a less volatile form could explain it. I've read elsewhere that very little of Earth's water was swept out during accretion, but perhaps silanes and alkanes or other hydrogen-rich compounds might have formed in the accretion disk, been swept out, and then been broken up and re-bound with other chemicals in the extreme environment of the accreting planet. Or there might have been enough free Si, C, and other chemicals with an affinity for hydrogen in the atmosphere or surface of proto-Earth to bond with hydrogen, and then break up when convected down into higher temperature and pressure regimes. My chemistry knowledge is pretty weak, so I don't know if either explanation is plausible.&lt;/p&gt;&#xA;" OwnerUserId="26779" LastEditorUserId="26779" LastEditDate="2022-04-29T18:53:02.390" LastActivityDate="2022-04-29T23:32:16.597" Title="How did hydrogen make its way into proto-Earth?" Tags="|geochemistry|planetary-formation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23782" PostTypeId="2" ParentId="23781" CreationDate="2022-04-29T23:32:16.597" Score="5" Body="&lt;p&gt;The article you've shared doesn't assume the hydrogen in the core came from the hydrogen in the protosolar nebula.&lt;br /&gt;&#xA;In fact it ignores all modern literature on planet formation, and just cites lab experiments and molecular dynamics simulations on the topic of hydrogen partitioning between a Si &amp;amp; O-rich phase and a Fe-rich phase. The hydrogen in their scenario is assumed to come from water in the mantle, as you see in their fig. 1, there is barely any to start with.&lt;br /&gt;&#xA;The amount of hydrogen that they assume is therefore generally consistent with a hydrogen-poor (relative to solar) initial condition for the mantle: If we look at where we have to start out in the protosolar nebula, we land at a hydrogen-rich &lt;span class=&quot;math-container&quot;&gt;$\rm [H/O]\approx 2\times10^{3}$&lt;/span&gt; (usually taken from the solar atmosphere as proxy).&lt;br /&gt;&#xA;In their simulations however, they start with a 'rocky' composition in one phase, i.e. olivine-type rocks somewhere along &lt;span class=&quot;math-container&quot;&gt;$\rm Fe_x Mg_{1-x}Si_yO_z$&lt;/span&gt;&#xA;and essentially pure iron in the other phase.&#xA;They have 12 H atoms diffusing around for 377 atoms total, so that gives a total H content in the simulation domain of 3%. Their quoted result in the abstract of 1% in the metal-rich phase then isn't all that exciting, I guess?&lt;/p&gt;&#xA;&lt;p&gt;But let us contain a key result here, that the ratio of hydrogen to oxygen of course would be very different now to the protosolar nebula, i.e. &lt;span class=&quot;math-container&quot;&gt;$[12/100]\sim1$&lt;/span&gt;%, where this low number compared to the protosolar value that you might have expected, is coming from the assumption of initial water content of the rock.&lt;br /&gt;&#xA;Note that I am comparing atom numbers here, where their 1% is a weight-percent.&lt;/p&gt;&#xA;&lt;p&gt;If you are interested, I can add a bit of discussion on how volatiles might get to the planet in the first place during the accretion process, but that would happen in the next few days.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2022-04-29T23:32:16.597" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23783" PostTypeId="2" ParentId="23770" CreationDate="2022-04-30T17:06:31.733" Score="1" Body="&lt;p&gt;The only (non NS) path that maintains a fixed bearing relative to true north is a &amp;quot;&lt;a href=&quot;https://en.m.wikipedia.org/wiki/Rhumb_line#:%7E:text=In%20navigation%2C%20a%20rhumb%20line,measured%20relative%20to%20true%20north.&quot; rel=&quot;nofollow noreferrer&quot;&gt;rhumb line&lt;/a&gt;&amp;quot;. By contrast, all other straight line paths will see their bearing change relative to north: mark any (non rhumb line) straight line over a globe and see that the angle between longitudes and your path changes. Note that this hard to visualize on a 2D map or computer monitor, though you might see it with Google Earth.&lt;/p&gt;&#xA;&lt;p&gt;As for declination, it is the angular correction made for the difference between magnetic north and true north and it varies over time and especially place. The declination changes with geographic position and must be accounted for when moving anywhere over the earth. Sailors must be especially vigilant about knowing exactly what the declination is for their position when traveling great distances using a compass; declination is irrelevant if using strictly GPS.&lt;/p&gt;&#xA;" OwnerUserId="7333" LastActivityDate="2022-04-30T17:06:31.733" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23784" PostTypeId="1" CreationDate="2022-04-30T19:33:42.460" Score="4" ViewCount="112" Body="&lt;p&gt;CNN's April 30, 2022 &lt;a href=&quot;https://edition.cnn.com/2022/04/30/us/cow-burps-methane-space-climate-trnd/index.html&quot; rel=&quot;noreferrer&quot;&gt;Planet-warming emissions from cow burps have been seen from space&lt;/a&gt; begins:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The emissions were detected by environmental data company GHGSat's high-resolution satellites in February, according to a news release from the company. In April the company's analysis confirmed that the emissions came from a cattle feedlot in California's Joaquin Valley.&lt;/p&gt;&#xA;&lt;p&gt;The satellites recorded five emissions, says GHGSat. If these emissions were sustained for just one year, enough gas would be released &amp;quot;to power 15,402 homes,&amp;quot; the company said.&lt;/p&gt;&#xA;&lt;p&gt;Methane emissions from cattle have been identified as a significant contributor to climate change. As cows digest their food, they release methane, mostly through their gassy burps. But the methane they burp up is a powerful greenhouse gas that traps heat in the atmosphere. The Food and Agriculture Organization (FAO) says that farm cattle contribute to &lt;a href=&quot;http://www.fao.org/news/story/en/item/197623/icode/&quot; rel=&quot;noreferrer&quot;&gt;10% of greenhouse gas emissions worldwide generated by human activity&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;And cattle farming is a major industry in California: The state has 650,000 beef cows as of 2019, according to the California Cattlemen's Association.&lt;/p&gt;&#xA;&lt;p&gt;Brody Wight, the sales director at GHGSat, told CNN this is the first time the company knows of in which scientists were able to use satellite imagery to pinpoint methane emissions from cattle farming. &lt;strong&gt;The company has three high-resolution satellites in orbit, which it has previously used to measure emissions from open-pit coal mines. Each satellite is just the size of a microwave oven, says GHGSat.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; What are the three high-resolution imaging satellites that GHGSat uses to make high spatial resolution images of methane emission (in this case, likely a cluster of cow burps) and how do these satellites image column-averaged ppb levels of methane above background? What kind of camera and wavelengths are used?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Graphic from the CNN article, showing column-average values of 20 to 100 ppb CH4 with an apparent spatial resolution of roughly tens of meters:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xOFk6.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xOFk6.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;An environmental data company captured images of methane emissions from cattle taken from space.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2022-05-02T11:30:40.650" Title="Cluster of cow burps now mapped; which satellites contribute to GHGSat's high-resolution maps of ppb levels of methane emission? How do they do it?" Tags="|atmosphere|earth-observation|satellites|instrumentation|methane|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23785" PostTypeId="2" ParentId="23784" CreationDate="2022-05-01T18:17:51.093" Score="3" Body="&lt;p&gt;A quick online search shows the &lt;a href=&quot;https://earth.esa.int/eogateway/missions/ghgsat&quot; rel=&quot;nofollow noreferrer&quot;&gt;GHGSat web page&lt;/a&gt; discussing the satellites and their capabilities (emphasis mine):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;GHGSat's vision is to become the global reference for the remote&#xA;sensing of greenhouse gas (GHG) emissions from any source in the&#xA;world. No other commercial or government satellite mission is&#xA;specifically designed for detecting and quantifying GHG emissions from&#xA;point sources as small as individual oil and gas wells.&lt;/p&gt;&#xA;&lt;p&gt;The GHGSat constellation currently &lt;strong&gt;consists of three satellites&lt;/strong&gt;,&#xA;&lt;strong&gt;GHGSat-D (&lt;em&gt;Claire&lt;/em&gt;)&lt;/strong&gt; launched in June 2016, &lt;strong&gt;GHGSat-C1 (&lt;em&gt;Iris&lt;/em&gt;)&lt;/strong&gt; launched in&#xA;September 2020, and &lt;strong&gt;GHGSat-C2 (&lt;em&gt;Hugo&lt;/em&gt;)&lt;/strong&gt; launched in January 2021.&lt;/p&gt;&#xA;&lt;p&gt;Each satellite is equipped with a wide-angle Fabry-Perot (WAF-P)&#xA;imaging spectrometer designed to measure the vertical column&#xA;abundances of greenhouse gases. &lt;strong&gt;GHGSat-D is capable of measuring both&#xA;methane and carbon dioxide, while GHGSat-C1 and GHGSat-C2 are&#xA;optimised for methane.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The instrumentation carried and procedure is discussed &lt;a href=&quot;https://earth.esa.int/eogateway/missions/ghgsat#:%7E:text=Each%20GHGSat%20satellite%20carries%20a%20proprietary%20imaging%20spectrometer%20for%20measuring%20facility%2Dlevel%20greenhouse%20gas%20emissions.&quot; rel=&quot;nofollow noreferrer&quot;&gt;further down the page&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The primary sensor on all GHGSat satellites is a Wide-Angle&#xA;Fabry-Perot (WAF-P) Imaging Spectrometer. This primary sensor produces&#xA;a hypercube consisting of a stack of overlapping, spectrally selected&#xA;images acquired within &amp;lt;30 seconds. This hypercube embeds, for each&#xA;ground pixel, information equivalent to hundreds of wavelengths from&#xA;the top-of-the-atmosphere spectral radiance. Once downloaded, the&#xA;hypercube is corrected for sensor response and instrument optics. The&#xA;gas column density and surface reflectance information are then&#xA;retrieved for each ground pixel using a measurement model which&#xA;includes surface, instrument and atmospheric contributions to&#xA;radiance. The resulting arrays are georeferenced, giving the &amp;quot;Surface&#xA;Reflectance Image&amp;quot; and one &amp;quot;Abundance Dataset&amp;quot; for methane.&lt;/p&gt;&#xA;&lt;p&gt;GHGSat satellites typically have a spatial resolution of 25 m (&amp;gt;50 m&#xA;for GHGSat-D) and the Field of View (FOV) of approximately 12 km x 12&#xA;km of these datasets allow gas plumes emitted from industrial sources&#xA;to be captured and distinguished from the surrounding background&#xA;concentrations, constituting a differential measurement.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The particular details concerning the operating ranges of the spectrometer mentioned are listed as&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;SWIR 1630-1675 nm, multiple bands in a proprietary configuration,&#xA;unpolarized&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;From Celestrak's &lt;a href=&quot;https://celestrak.org/satcat/search.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;satcat&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;GHGSat-D: 2016-040D, 41602&lt;/li&gt;&#xA;&lt;li&gt;GHGSAT-C1: 2020-061G, 46278&lt;/li&gt;&#xA;&lt;li&gt;GHGSAT-C2: 2021-006DA, 47509&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6057" LastEditorUserId="-1" LastEditDate="2022-09-27T22:27:30.220" LastActivityDate="2022-05-02T11:30:40.650" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23786" PostTypeId="1" CreationDate="2022-05-02T02:10:13.570" Score="3" ViewCount="287" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;In the Himalayan reaches, the course of these rivers is highly&#xA;tortuous, but over the Plains they display a strong meandering&#xA;tendency and shift their courses frequently.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is what I saw about the Himalayan rivers in my textbook. I do understand why they meander in the Plains (Northern Plains in India), but I don't get how meandering in the Plains is different from being 'tortuous' in the higher mountain reaches. What exactly is the difference between 'tortuous' and 'meandering' in this context?&lt;/p&gt;&#xA;" OwnerUserId="22020" LastActivityDate="2022-05-02T02:10:13.570" Title="Why are the Himalayan rivers highly tortuous in the mountain reaches?" Tags="|sedimentology|mountains|rivers|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23787" PostTypeId="1" AcceptedAnswerId="23788" CreationDate="2022-05-02T08:37:47.037" Score="4" ViewCount="50" Body="&lt;p&gt;I want to calculate growing degree days.&lt;/p&gt;&#xA;&lt;p&gt;I have hourly data of temperature between the hours of 00:00 and 23:59.&lt;/p&gt;&#xA;&lt;p&gt;I want to calculate the growing degree days and I saw that I need the minimum,maximum and mean temperatures. However, I don't know if I should filter my data to contain temperature data only for the daylight time or to use the whole day temperature.&lt;/p&gt;&#xA;&lt;p&gt;What is the right data to use for the GDD calcualtion?&lt;/p&gt;&#xA;" OwnerUserId="26790" LastEditorUserId="2470" LastEditDate="2022-05-02T13:02:53.983" LastActivityDate="2022-05-02T13:54:08.527" Title="Minimum temperature in Growing Degree Day (GDD) - from daytime or from the whole day?" Tags="|temperature|agriculture|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23788" PostTypeId="2" ParentId="23787" CreationDate="2022-05-02T13:54:08.527" Score="1" Body="&lt;p&gt;I have no actual familiarity myself with implementing growing degree days itself.&lt;/p&gt;&#xA;&lt;p&gt;That said, in reading through some references like (&lt;a href=&quot;https://mrcc.purdue.edu/gismaps/info/gddinfo.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;), (&lt;a href=&quot;https://extension.psu.edu/understanding-growing-degree-days&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;), and (&lt;a href=&quot;https://farmwest.com/climate/calculator-information/gdd/&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;) I see no indication that it should be filtered.&lt;/p&gt;&#xA;&lt;p&gt;The terminology also sounds to stem from the longer used heating degree day and cooling degree day, which I know is done from just the max and min over the 24 hour day (as &lt;a href=&quot;https://www.weather.gov/lch/f6info&quot; rel=&quot;nofollow noreferrer&quot;&gt;this NOAA page suggests&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;And in addition, the lowest temperature of the day usually occurs right near or just after dawn, so filtering it to &amp;quot;daytime&amp;quot; temperatures being when the sun is up would basically include roughly the coldest (and hottest) temperature of the day anyways.&lt;/p&gt;&#xA;&lt;p&gt;So while I've never interacted with this specific metric, everything suggests to me that you would just use the values over a standard 24 hour day.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2022-05-02T13:54:08.527" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23791" PostTypeId="2" ParentId="17602" CreationDate="2022-05-03T14:35:46.567" Score="7" Body="&lt;p&gt;The solution you are looking for is called &amp;quot;artificial recharge of aquifers&amp;quot; or &amp;quot;managed underground storage of recoverable water&amp;quot;, among several other names.&lt;/p&gt;&#xA;&lt;p&gt;Several different techniques have been developed for this in the past, and which one is applicable depends strongly on the specifics of your local situation. I'll describe the most frequently used techniques shortly, and link to two freely available e-books where you can look up all the details for planning your system:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Watershed management.&lt;/strong&gt; This means the enhancement of natural recharge into the aquifer and involves a modification of large parts of the watershed of a local river. You can look into permaculture design techniques (swales, keyline ploughing and ponds) for suitable techniques. This is often the most suitable technique because it also helps in water management on local farms and prevents soil erosion and other damage by runoff water.&lt;/p&gt;&#xA;&lt;p&gt;Trees can play an important role in this technique. Up to a certain tree density of somewhere between 10% and 30% canopy cover, the benefits of trees for groundwater recharge outweigh the drawback that trees also consume more water. That is, when planting trees not too densely, they help to increase groundwater levels by keeping the pores in the soil open through which water can percolate down to the groundwater level. This is the result of some relatively new research, so the exact impacts and implications of this mechanism are not yet explored. The existing research work is available &lt;a href=&quot;https://www.nature.com/articles/srep21930&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;https://pub.epsilon.slu.se/13553/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, with an &lt;a href=&quot;https://www.siani.se/news-story/can-trees-improve-groundwater-levels/&quot; rel=&quot;nofollow noreferrer&quot;&gt;introductory article&lt;/a&gt; available as well.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Surface spreading.&lt;/strong&gt; This category includes techniques such as recharge basins, modified stream beds, pits, shafts and others. The idea is to enhance percolation into the ground from surface area that catch stormwater. Maintenance often includes raking the bottom of recharge basins to prevent clogging from clay particles and other fines. Plus, this can only recharge into aquifers with no waterproof layers above them, and requires large land areas. But where this is possible, it is often the cheapest option.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Vadose zone wells.&lt;/strong&gt; Also called recharge wells. Dry borehole wells or specifically drilled wells are used to recharge the aquifer. This can work with aquifers that have waterproof layers above them, but the main problem is clogging by fine particles over time, which cannot be effectively reversed. Overall, quite an expensive technique.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Aquifer storage and recovery (ASR) wells.&lt;/strong&gt; Borehole wells that are designed both for recharge of the aquifer and recovery of water from the same well.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;Relevant open access literature for further details and instructions:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;&lt;a href=&quot;https://nap.nationalacademies.org/catalog/12057/prospects-for-managed-underground-storage-of-recoverable-water&quot; rel=&quot;nofollow noreferrer&quot;&gt;Prospects for Managed Underground Storage of Recoverable Water&lt;/a&gt;&lt;/strong&gt;. Published by National Research Council. 2008. 351 pages.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;&lt;a href=&quot;http://www.oas.org/usde/publications/Unit/oea59e/begin.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source Book of Alternative Technologies for Freshwater Augmentation in Latin America and the Caribbean&lt;/a&gt;&lt;/strong&gt;. Published by Unit of Sustainable Development and Environment, General Secretariat, Organization of American States. 1997. Here relevant: chapter &amp;quot;&lt;a href=&quot;http://www.oas.org/usde/publications/Unit/oea59e/ch18.htm#1.9%20artificial%20recharge%20of%20aquifers&quot; rel=&quot;nofollow noreferrer&quot;&gt;1.9 Artificial recharge of aquifers&lt;/a&gt;&amp;quot;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="12301" LastEditorUserId="12301" LastEditDate="2022-05-21T22:39:29.217" LastActivityDate="2022-05-21T22:39:29.217" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23792" PostTypeId="1" AcceptedAnswerId="23802" CreationDate="2022-05-03T15:54:41.477" Score="6" ViewCount="138" Body="&lt;p&gt;I recently rafted the San Juan river in Southern Utah, which flows into the Lake Powell reservoir.  When the water levels in Lake Powell were very high, it extended far upstream into the San Juan River.  This caused the river to stagnate and deposit enormous amounts of silt in the canyon.&lt;/p&gt;&#xA;&lt;p&gt;When Lake Powell water level subsequently dropped, the river carved new meanders through the resulting silt beds, but within the much larger meanders that form the canyon. (Satellite Imagery from Google Maps)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ly6qt.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ly6qt.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The San Juan doesn't flash flood anymore due to the flow regulation of the upstream Navajo Dam, so it hasn't been able to wash out the silt.&lt;/p&gt;&#xA;&lt;p&gt;Apparently &amp;quot;meanders in meanders&amp;quot; is not a unique phenomenon as &lt;a href=&quot;https://www.flickr.com/photos/arenamontanus/4675483210/&quot; rel=&quot;noreferrer&quot;&gt;Anders Sandberg has also captured it here&lt;/a&gt;, but I don't know where he took this picture.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/w23ZP.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/w23ZP.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Question: &lt;strong&gt;Can &amp;quot;meanders in meanders&amp;quot; also form naturally?&lt;/strong&gt; How does this happen? Also, if there is a more scientific name for this phenomenon, it would be helpful.&lt;/p&gt;&#xA;" OwnerUserId="22592" LastActivityDate="2022-05-11T16:17:55.130" Title="Can &quot;meanders in meanders&quot; form naturally?" Tags="|geophysics|rivers|erosion|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23794" PostTypeId="2" ParentId="23792" CreationDate="2022-05-05T15:45:25.413" Score="3" Body="&lt;p&gt;In the case that you show there are so-called incised meanders cut into the bedrock in which material has been deposited when lake levels have been high. When lake levels have dropped the sediments and the slope of the valley is favourable for meandering.&lt;/p&gt;&#xA;&lt;p&gt;Meandering rivers form at low slopes and in fine partially cohesive sediments. Thus the meandering patterns says much about the slope of the former lake bed and the type of sediment laid down on the lake bottom. With steeper slopes or with diffreent grain sizes, the meandering may not be the resultring river pattern.&lt;/p&gt;&#xA;&lt;p&gt;The observation that a meandering river has developed in an old incised meandering river valley is mainly fortuitous since the present river does not require a wide valley to develop meandering. If the river would have larger discharges it likely would require a wider valley to develop such intricate meander patterns. At the same time the bedrock valley floor is likely at some depth below the current valley surface so the large scale valley meander pattern may become more complicated at depth.&lt;/p&gt;&#xA;&lt;p&gt;A good and recent (at the time of providing the response) summary of meandering is:&lt;/p&gt;&#xA;&lt;p&gt;Hooke JM, 2022. River meandering. In: Shroeder, JF (ed) Treatise on Geomorphology (Second Edition). Oxford, Academic press. 480-516.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="81" LastEditDate="2022-05-05T15:51:12.633" LastActivityDate="2022-05-05T15:51:12.633" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23795" PostTypeId="2" ParentId="23780" CreationDate="2022-05-05T16:17:38.403" Score="3" Body="&lt;p&gt;True air temperature may be an elusive quantity to measure but shielding thermometers and sensors from direct solar radiation has been the main approach for a long time. The best results are provided by so-called aspirated radiation covers where sensors sit inside a radiation cover which is augmented by a fan that allows fresh air to pass across the sensor and therefore allowing fresh air, not air warmed by the shield, to be the basis for the measurement.&lt;/p&gt;&#xA;&lt;p&gt;There are lots of reports on comparisons between shields provided by scientists and makers of radiations shields (as simple search will give numerous sources). These indicate that deviations of up to 7 degrees C can occur if non-aspirated shields heat up during zero wind conditions. That aside the Swedish Meteorological and Hydrological Institute use the Vaisala shields, linked in a comment to the question, as a standard.&lt;/p&gt;&#xA;&lt;p&gt;At the Tarfala Research Station we have compared the old wood Stevenson screens with Young plastic screens and aspirated sensors and the old Stevenson screen actually performs better that the smaller plastic screens. There may be several reasons for this such as larger thermal inertia in the wooden screens and also larger volume of air inside the screen and likely larger air flow through those screens than the smaller plastic screens. Nevertheless, the aspirated screens are superior because they more quickly reflect changes in air temperature.&lt;/p&gt;&#xA;&lt;p&gt;One could always argue what is the true air temperature. This will depend on where measurements are made relative to ground and also wind conditions. So any temperature measurement will likely be associated with errors. At the same time one could ask oneself what accuracy is required and for what reason we measure. Changing measurement method may introduce offsets that are simply instrumental and not necessarily climatological so great care has to be taken when interpreting temperature records involving changes in recording environment.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="2470" LastEditDate="2022-05-05T17:53:10.457" LastActivityDate="2022-05-05T17:53:10.457" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23796" PostTypeId="1" AcceptedAnswerId="23800" CreationDate="2022-05-06T19:15:46.347" Score="3" ViewCount="104" Body="&lt;p&gt;In reflection seismology, we create a source with an airgun and then use receivers to register acoustic waves (an approximation) at the surface. From these measurements, we can predict a velocity field &lt;span class=&quot;math-container&quot;&gt;$c=c(x)$&lt;/span&gt;. This can be seen in the figure below taken from a research group Karlsruhe Institute of Technology at this &lt;a href=&quot;https://www.waves.kit.edu/C2.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Aju5H.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Aju5H.png&quot; alt=&quot;Reflection Seismology Graphic&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The 2D model pictured here shows (the red, yellow, and black colorbar) shows a model of P-wave velocity. This picture shows you the geometry of material interfaces of the subsurface. However, it does not directly tell you anything directly about rock composition. Table 5.4a at this &lt;a href=&quot;https://wiki.seg.org/wiki/Velocities_in_limestone_and_sandstone&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt; suggests that it would be hard to tell the difference between limestone and sandstone at 30% porosity. This would make predicting a P-wave velocity field possibly less useful than a direct map of the rock type.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Motivated by the discussion above, my questions are below.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;(1) Is rock type not that important and geometry all that matters for the purpose of exploration geophysics? For reservoir modeling, is knowing the rock type important?&lt;/p&gt;&#xA;&lt;p&gt;(2) If I get a core out of just one spot and map rock type with depth, can I then infer rock type over the whole field? For example, in this image, if I saw the black part correlates with, say, limestone, can I just blindly say &amp;quot;okay everywhere else in this image where I see black is probably limestone&amp;quot; (of course, this may lead to errors but seems a reasonable approach to me)?&lt;/p&gt;&#xA;&lt;p&gt;(3) If I am able to extract a porosity, permeability field, an S-wave velocity field, and possibly many other fields, can I infer the rock type or at least, decrease my uncertainty in predicting rock type?&lt;/p&gt;&#xA;&lt;p&gt;(4) In light of (1)-(3), I imagine that on large projects, geophysicists give their images to people more experienced with stratigraphy and the like. What kinds of questions can geophysicists answered with reasonable confidence? What kinds of questions can stratigraphers answer with/without given images from a geophysicist?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;NOTE: I identify as an applied mathematician, so feel free to over-explain any geology.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="26812" LastEditorUserId="28050" LastEditDate="2022-05-10T14:12:52.360" LastActivityDate="2022-05-16T16:50:54.853" Title="Predicting rock type from seismic processing" Tags="|geophysics|seismic|stratigraphy|inversion|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23797" PostTypeId="2" ParentId="17602" CreationDate="2022-05-07T10:32:59.133" Score="2" Body="&lt;ol&gt;&#xA;&lt;li&gt;Sand dam.    A sand dam is a very low seasonal dam built on sand rivers....when it rains it usually just carries sand down. Bit the damage acts as an alluvial deposit. Slots in the dam allow water and silt to flow out. But the sand acts as a sponge holding water in dry days which can be well pumped or stored.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/z4sbj.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/z4sbj.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Ground recharge pit.    Otherwise known as a percolation pit. Takes a standard bore well drilled initially for water... and modify with a filter and layers of rock, sand and filter fabric and activated carbon. When it rains or Floods water by gravity finds its way into the pit, drains and filters back into the well.[&lt;img src=&quot;https://i.stack.imgur.com/JqG43.png&quot; alt=&quot;enter image description here&quot; /&gt;]&lt;/li&gt;&#xA;&lt;li&gt;Zai: zais are unique in sense that they help soil. Available is a 1-2 foot wide by 1 meter deep hole. In farming preseason holes are filled with compost and manure and act as catchers for rainwater....then when it's time the area is planted. This system does not employ for ground water recharge but if accessory holes 3-9 meters deep are drilled they can allow 10-15% of the water to reintroduce into deep soil profile.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2022-05-07T10:32:59.133" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23800" PostTypeId="2" ParentId="23796" CreationDate="2022-05-10T14:11:34.973" Score="6" Body="&lt;p&gt;This is a ginormous question; a complete answer is probably worth an MSc in exploration geophysics. But I can try to give some pointers for places to find out more.&lt;/p&gt;&#xA;&lt;p&gt;Preface: in general, considering applied geoscience in the service of natural resource mapping and prediction (petroleum, water, geothermal, etc), we're interested in some specific rock properties. These might be, in very broad strokes and approximate order of usefulness:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Porosity and permeability.&lt;/li&gt;&#xA;&lt;li&gt;Geochemistry (fluid composition, water salinity).&lt;/li&gt;&#xA;&lt;li&gt;Other petrophysics (temperature, pressure).&lt;/li&gt;&#xA;&lt;li&gt;Lots of other things like lithology (rock type), stratigraphy (rock geometry), geomechanics (stress, fractures, etc).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;We're usually only interested in &amp;quot;first-order&amp;quot; (from a seismic point of view) acoustic/elastic properties like P-wave velocity (&lt;span class=&quot;math-container&quot;&gt;$V_\mathrm{P}$&lt;/span&gt;), S-wave velocity (&lt;span class=&quot;math-container&quot;&gt;$V_\mathrm{S}$&lt;/span&gt;) and density (&lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt;) insofar as we can use that information to process seismic data or infer porosity, lithology, etc.&lt;/p&gt;&#xA;&lt;p&gt;The problem is that I am not allowed to measure anything I care about directly. Everything is filtered through the earth (seismic waves) and/or various instruments, and everything is prone to error, bias and uncertainty. Basically, you're looking at just about the hardest inverse problem you can imagine.&lt;/p&gt;&#xA;&lt;h3&gt;What about the questions?&lt;/h3&gt;&#xA;&lt;p&gt;Oh right.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Rock type is important,&lt;/strong&gt; because if I know the rock type I can make a lot of pretty good guesses about a lot of things I'm interested in. I know what kinds of porosities sandstones have, and what kind of mineralogy. I know about the A formation and the B formation, so I can correlate them over large distances. I know how old those rocks are and where the sea was at that time, so I know where hydrocarbons might migrate from. You get the idea. (I know that sounds pretty abstract, but eventually this information gets us closer to the list of properties I gave you earlier.)&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;No, velocity and lithology are not correlated like that.&lt;/strong&gt; If only! Now, in seismic processing, we don't care too much about lithology, because the P and S velocity and the density are all we need to reconstruct the wavefield. But small things — increase porosity, change the pressure, add a tiny amount of natural gas ('fizz gas') — have a  large effect on velocity and density. To make things worse, fluids don't sustain S-waves. To make things even worse, wave modes convert between each other at elastic boundaries ('mode conversion'). Then there's dispersion. And attenuation. It's a nightmare, basically. Seismic imaging is a miracle.&lt;p&gt;By the way, we don't just collect core from boreholes. We also measure a lot of things like velocity, density, and so on. Some of these things are even &lt;em&gt;almost&lt;/em&gt; super-useful things like porosity and lithology. This sounds really useful, and it is, but remember that all of those measurements are broken in various ways (the borehole walls are rugged, the rock is invaded by drilling mud, and so on.).&lt;/p&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;You definitely can.&lt;/strong&gt; In general this is called 'seismic inversion' and it's a billion-dollar industry working on decades of research and development. In many ways, along with 'fluid composition', it's the holy grail of seismic analysis. Note that the only fields you can really extract from seismic are &lt;span class=&quot;math-container&quot;&gt;$V_\mathrm{P}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$V_\mathrm{S}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; — everything else is a second-order property you'll have to predict.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Indeed, seismic interpretation is a multidisciplinary activity.&lt;/strong&gt; Geologists are good at interpreting the geometric properties, such as stratigraphy and fault networks. Geophysicists understand the artifacts better (seismic is a bandlimited wavefield recorded in a natural environment, so there's interference, resonance, diffraction, coloured and coherent noise, echoes (so-called multiples), and so on. Like I said, it's a nightmare.)&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;h3&gt;Last thing: offset&lt;/h3&gt;&#xA;&lt;p&gt;From the point of view of inversion, there's something missing from the diagram in your post: 'offset'. As the ship moves, each point in the earth will be imaged in turn by those green receivers, each of which is a difference distance from the source (red). So we don't just get one trace at each location, we get a whole collection of them, all recorded at different reflection angles. Luckily, the nature of the reflected energy changes with offset, eventually going critical at long offsets. At short offsets (small angles), we only get information about &lt;span class=&quot;math-container&quot;&gt;$V_\mathrm{P}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt;; the elastic information is contained in the far offsets (large angle of reflection).&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2022-05-16T16:50:54.853" LastActivityDate="2022-05-16T16:50:54.853" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23801" PostTypeId="1" CreationDate="2022-05-11T07:26:37.070" Score="1" ViewCount="105" Body="&lt;p&gt;Say a given populated area is considered an &amp;quot;urban heat island&amp;quot;, this would mean that during summer, temperatures will be higher in that area.&lt;/p&gt;&#xA;&lt;p&gt;But what about winter? One could argue that higher temperatures during winter are actually a positive effect. Therefore, I'm trying to understand what can be considered a negative effect during winter time?&lt;/p&gt;&#xA;" OwnerUserId="26835" LastEditorUserId="2470" LastEditDate="2022-05-12T05:59:42.853" LastActivityDate="2022-05-12T05:59:42.853" Title="Urban heat island effect during winter time?" Tags="|climate-change|temperature|climate-models|urban-climate|winter|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23802" PostTypeId="2" ParentId="23792" CreationDate="2022-05-11T15:28:22.540" Score="3" Body="&lt;h3&gt;Yes.&lt;/h3&gt;&#xA;&lt;p&gt;Here's an example of &lt;a href=&quot;https://www.google.com/maps/@62.1147218,83.0073387,22229m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;a river in Siberia&lt;/a&gt; (at about 62°08'N 83°06'E) that appears to be unimpinged by human activity. It's a bit hard to see both scales at once, but the river meanders all over the place.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lmDoU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lmDoU.jpg&quot; alt=&quot;A meandering river in Siberia&quot; /&gt;&lt;/a&gt;&#xA;I'll refer you to &lt;a href=&quot;https://earthscience.stackexchange.com/users/81/peter-jansson&quot;&gt;Peter Jansson's&lt;/a&gt; answer for more of an explanation, but the first order idea is that the meandering valley (the large-scale landform) forms under one set of conditions and the meandering channel (the small scale channel) under another. Those conditions might change seasonally (as in Utah) or historically (as I suspect is the case in the Siberia example).&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="6298" LastEditDate="2022-05-11T16:17:55.130" LastActivityDate="2022-05-11T16:17:55.130" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23803" PostTypeId="1" CreationDate="2022-05-11T19:16:48.240" Score="3" ViewCount="479" Body="&lt;p&gt;For the sake of the example, let's assume a crater on Earth roughly twelve miles in diameter.&lt;/p&gt;&#xA;&lt;p&gt;Is there a way to calculate a range between how deep or shallow this crater would be?&lt;/p&gt;&#xA;" OwnerUserId="7982" LastActivityDate="2022-05-12T01:23:17.883" Title="Is there a way to calculate crater depth?" Tags="|geophysics|meteorite|impacts|impact-craters|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23804" PostTypeId="2" ParentId="23803" CreationDate="2022-05-12T01:23:17.883" Score="1" Body="&lt;p&gt;If you search the internet there will be a number of papers discussing the depth to diameter ratios of craters on various bodies throughout the solar system (Moon, Mars, Vesta, asteroid 162173 Ryugu). Ultimately the depth and the overall wall angle of a crater will depend on the type of geological material hosting the crater.&lt;/p&gt;&#xA;&lt;p&gt;Craters in loose material, such as sand, will have shallow craters with shallow wall angles. Craters in competent material such a basalt will have deeper craters and walls with higher slope angles.&lt;/p&gt;&#xA;&lt;p&gt;On &lt;a href=&quot;https://www.lpi.usra.edu%20%E2%80%BA%20meetings%20%E2%80%BA%20lpsc2012%20%E2%80%BA%20pdf%20%E2%80%BA%201415.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Vesta&lt;/a&gt; the depth to diameter ratios vary between 0.05 and 0.4. Where as on &lt;a href=&quot;https://astronomy.com/magazine/ask-astro/2012/07/lunar-impacts&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Moon&lt;/a&gt;,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Their depths are only a small fraction, about 1/15 to 1/25, of their diameters. So these “deep pits” are actually shallower than dinner plates.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In decimals, they are ratios between 0.067 and 0.04.&lt;/p&gt;&#xA;&lt;p&gt;Newer lunar craters, such as Linne, with a diameter of 2.2 km and a depth of 550 m has a ratio of 0.25.&lt;/p&gt;&#xA;&lt;p&gt;The differences in depth to diameter ratios reflects to the different rock types where the craters are located and the properties for those rock types.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-05-12T01:23:17.883" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23805" PostTypeId="2" ParentId="19901" CreationDate="2022-05-12T16:43:23.627" Score="1" Body="&lt;p&gt;&lt;a href=&quot;https://gmd.copernicus.org/articles/7/387/2014/gmd-7-387-2014.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;This paper&lt;/a&gt; By Fiddes &amp;amp; Gruber (&lt;em&gt;TopoSCALE: downscaling gridded climate data in complex terrain&lt;/em&gt;) provides a method to partition direct and diffuse from ERA-Interim.  The results could easily be applied to ERA5.&lt;/p&gt;&#xA;&lt;p&gt;It uses a clearness index approximation from Ruiz-Arias et al. (2010)&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$k_t = SW / SW_{toa}$&lt;/span&gt; (eq C11) where &lt;span class=&quot;math-container&quot;&gt;$ SW_{toa} $&lt;/span&gt; is the shortwave at the top-of-atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;then,&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$SW_{diffuse} = 0.952 - 1.041 e^{-exp(2.3 - 4.702k_t)}$&lt;/span&gt; (eq C12)&lt;/p&gt;&#xA;&lt;p&gt;You should be able to get top-of-atmosphere SW from ERA5, or possibly calculate it based on solar geometry.&lt;/p&gt;&#xA;" OwnerUserId="14348" LastActivityDate="2022-05-12T16:43:23.627" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23806" PostTypeId="1" CreationDate="2022-05-12T22:59:57.450" Score="3" ViewCount="61" Body="&lt;p&gt;When looking at GOES satellite imagery, in the visible channels. I have noticed these &amp;quot;lines&amp;quot; if you will, usually forms in Cumulus fields. I understand the process of the 'Mackerel sky' (Herringbone Clouds) and how capping creates the appearance of the lines of cumulus etc... But, there seems to sometimes be a stationary line of descending air that causes the clouds to 'dissipate' / disappear and then re-appear on the other side. Is this an imagery anomaly due to the stretching of the picture at higher latitudes? or Atmospheric Gravity waves? Any idea's?&lt;/p&gt;&#xA;&lt;p&gt;Here are some screenshots with red lines marking the area's I'm talking about and there are links to full video's below. You will probably have to watch the video's to get a good idea of what I'm talking about.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zk2T9.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zk2T9.jpg&quot; alt=&quot;GOES Visible Imagery&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;VIDEO &lt;a href=&quot;https://drive.google.com/file/d/1hePhBvXkllpepRjx7ceU_v_NZJWWm1NY/view?usp=sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;HERE&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/so4e0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/so4e0.jpg&quot; alt=&quot;GOES Visible&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;VIDEO &lt;a href=&quot;https://drive.google.com/file/d/1i7lSZ68H_imbcW5J3bB-TTtf-2RP-XQy/view?usp=sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;HERE&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This one might be the same process, but I'm not sure?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6U20q.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6U20q.jpg&quot; alt=&quot;GOES Satellite&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;VIDEO &lt;a href=&quot;https://drive.google.com/file/d/1hebo0eKUHuYg3vQ4KWVRu75yLrZ3U0kq/view?usp=sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;HERE&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26840" LastEditorUserId="26840" LastEditDate="2022-05-12T23:32:03.730" LastActivityDate="2022-05-12T23:32:03.730" Title="Visible satellite imagery, atmospheric anomaly (descending air) in cumulus fields?" Tags="|meteorology|atmosphere|remote-sensing|weather-satellites|mesoscale-meteorology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23808" PostTypeId="1" CreationDate="2022-05-13T06:43:58.780" Score="3" ViewCount="114" Body="&lt;p&gt;I want to interpolate isotope data of precipitation and display it on a map. The data are available as a CSV file.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;   Country Latitude Longitude  Altitude  Sample Name        Date      H2  Year  month      dates&#xA;5         DE  511.622   149.506       238       199706  15.06.1997   -71.7  1997      6 1997-06-15&#xA;6         DE  511.622   149.506       238       199707  15.07.1997   -70.1  1997      7 1997-07-15&#xA;7         DE  511.622   149.506       238       199708  15.08.1997   -64.5  1997      8 1997-08-15&#xA;8         DE  511.622   149.506       238       199709  15.09.1997   -39.1  1997      9 1997-09-15&#xA;9         DE  511.622   149.506       238       199710  15.10.1997   -56.4  1997     10 1997-10-15&#xA;...      ...      ...       ...       ...          ...         ...     ...   ...    ...        ...&#xA;4995      DE  490.422   121.019       365       201304  15.04.2013  -41.86  2013      4 2013-04-15&#xA;4996      DE  490.422   121.019       365       201305  15.05.2013  -68.03  2013      5 2013-05-15&#xA;4997      DE  490.422   121.019       365       201306  15.06.2013  -54.98  2013      6 2013-06-15&#xA;4998      DE  490.422   121.019       365       201307  15.07.2013  -39.23  2013      7 2013-07-15&#xA;4999      DE  490.422   121.019       365       201308  15.08.2013  -46.93  2013      8 2013-08-15&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;With the package Pykrige I could make first interpolations, but I want my data to be interpolated and displayed similar to the R package:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://bookdown.org/content/782/introduction.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://bookdown.org/content/782/introduction.html&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Is there a similar package for Python, which is often used in geostatisics to represent chemicals in precipitation? I ask this because I have not found anything myself.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-05-13T07:36:02.147" LastActivityDate="2024-02-01T03:02:50.303" Title="What is the best way to interpolate Isotopic data and display them?" Tags="|climate-models|mapping|python|isotopic|interpolation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23809" PostTypeId="1" CreationDate="2022-05-13T13:20:33.633" Score="1" ViewCount="50" Body="&lt;p&gt;I have another question, is there a package that interpolates precipitation data taking into account mountains and oceans? I have so far used Numpy and Basemap but as you can see in the code, the data from Europe affect the data from North America! This distorts the results and must be prevented at all costs.&lt;/p&gt;&#xA;&lt;p&gt;(I am aware that my interpolation is just very simplified)&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import matplotlib.pyplot as plt&#xA;import numpy as np&#xA;from scipy.interpolate import griddata&#xA;from mpl_toolkits.basemap import Basemap&#xA;from matplotlib.colors import LinearSegmentedColormap&#xA;from matplotlib.patches import Path, PathPatch&#xA;&#xA;# data coordinates and values&#xA;x = np.array([6.47, 4.8, 1.94, -4.57, 5.78, 3.95, 5.45, 0.38, 7.13, 12.43, 11.59, -1.083333333, -60.996, -83.144 ])&#xA;y = np.array([46.37, 43.9, 47.83, 48.36, 44.95, 43.57, 43.45, 43.12, 43.92, 51.35, 48.22, 52.88333333, 50.958, 37.02])&#xA;z = np.array([-29.5, -27.6, -32.5, -32.4, -16.0, -0.1, -12.3, -15.2, -36.2,  -20.6,-38.2, -38.2, -2.0, -4.0  ])&#xA;&#xA;# target grid to interpolate to&#xA;xi =np.arange(-100, 100, 1, dtype='float64')&#xA;yi =np.arange(-100,100, 1, dtype='float64')&#xA;xi, yi = np.meshgrid(xi, yi)&#xA;&#xA;# interpolate&#xA;zi = griddata((x,y),z,(xi,yi),method='cubic')&#xA;&#xA;fig, ax = plt.subplots(figsize=(10,10))&#xA;m = Basemap(llcrnrlon=x.min()-0.1,llcrnrlat=y.min()-0.1,urcrnrlon=x.max()+0.1,urcrnrlat=y.max()+0.1, projection='merc', resolution='h',area_thresh=1000.,ax=ax)&#xA;&#xA;m.drawcoastlines() #draw coastlines on the map&#xA;x,y=m(xi, yi) # convert the coordinates into the map scales&#xA;cs=ax.contourf(x, y, zi, np.linspace(-40, 0),extend='both',cmap='jet') #plot the data on the map.&#xA;plt.scatter(x, y)&#xA;plt.show()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Oh and if someone knows how I can delete these meshgrid points from Numpy, I would be very happy about a short answer, because this I have somehow not found (which I myself find very strange)&lt;/p&gt;&#xA;&lt;p&gt;Edit: Normally the ocean is covered with a mask, but this would make the code much too long&lt;/p&gt;&#xA;&lt;p&gt;Result:&lt;a href=&quot;https://i.stack.imgur.com/drw6s.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/drw6s.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2022-05-13T13:20:33.633" Title="Complex interpolation for Isotopic data" Tags="|models|climate-models|mapping|python|interpolation|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23810" PostTypeId="1" CreationDate="2022-05-13T17:24:46.273" Score="1" ViewCount="47" Body="&lt;p&gt;Before asking my agriculture related question I would like to give some context being from an engineering background .&lt;/p&gt;&#xA;&lt;p&gt;Today Internet of Things (IOT) and Embedded firmware/hardware modules revolutionized innovation in many sectors including agriculture in what is  called Precision Agriculture where every input attribute to the plant environment like nutrients concentration pattern over time and wave length and intensity of light pattern over time can be implemented and controlled and automated precisely using IOT controlled fluid/nutrient pumps and led of different wave lengths and all that can&#xA;be real time monitored and controlled as well.&lt;/p&gt;&#xA;&lt;p&gt;Now, my questions related to agriculture:&lt;/p&gt;&#xA;&lt;p&gt;Is there some standard numerical tabular or graphical data about concentration patterns, light wave length patterns, rules that relate the quality, standard nutritional and chemical facts of the final fruit/vegetable to these patterns from a plant biochemical perspective so that if these patterns are implemented using such IOT system the quality and measured nutrition facts of the final fruit or vegetable can be tailored to meet specific requirement for the final crop?&lt;/p&gt;&#xA;&lt;p&gt;Second Question, what is the name of the field studying that and how to get such numerical data if exist?&lt;/p&gt;&#xA;" OwnerUserId="26843" LastEditorUserId="2470" LastEditDate="2022-05-13T18:53:10.527" LastActivityDate="2022-05-13T18:53:10.527" Title="Precision Agriculture using IOT System" Tags="|agriculture|" AnswerCount="0" CommentCount="2" ClosedDate="2022-05-15T16:50:27.523" ContentLicense="CC BY-SA 4.0" />
  <row Id="23811" PostTypeId="1" CreationDate="2022-05-14T09:00:54.677" Score="4" ViewCount="128" Body="&lt;p&gt;There have been several papers [failures of the review process] that have argued that the post-industrial rise in atmospheric &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; is primarily a natural phenomenon, or have sought to minimise the anthropogenic contribution.  This is a recent example:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;K. Skrable, G. Chabot and Clayton French, &amp;quot;World Atmospheric CO2, Its&#xA;14C Specific Activity, Non-fossil Component, Anthropogenic Fossil&#xA;Component, and Emissions (1750–2018)&amp;quot;, Health Physics: February 2022 -&#xA;Volume 122 - Issue 2 - p 291-305 doi: &lt;a href=&quot;https://dx.doi.org/10.1097/HP.0000000000001485&quot; rel=&quot;nofollow noreferrer&quot;&gt;10.1097/HP.0000000000001485&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Abstract&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;After 1750 and the onset of the industrial revolution, the&#xA;anthropogenic fossil component and the non-fossil component in the&#xA;total atmospheric CO2 concentration, C(t), began to increase. Despite&#xA;the lack of knowledge of these two components, claims that all or most&#xA;of the increase in C(t) since 1800 has been due to the anthropogenic&#xA;fossil component have continued since they began in 1960 with “Keeling&#xA;Curve: Increase in CO2 from burning fossil fuel.” Data and plots of&#xA;annual anthropogenic fossil CO2 emissions and concentrations, C(t),&#xA;published by the Energy Information Administration, are expanded in&#xA;this paper. Additions include annual mean values in 1750 through 2018&#xA;of the 14C specific activity, concentrations of the two components,&#xA;and their changes from values in 1750. The specific activity of 14C in&#xA;the atmosphere gets reduced by a dilution effect when fossil CO2,&#xA;which is devoid of 14C, enters the atmosphere. We have used the&#xA;results of this effect to quantify the two components. All results&#xA;covering the period from 1750 through 2018 are listed in a table and&#xA;plotted in figures. These results negate claims that the increase in&#xA;C(t) since 1800 has been dominated by the increase of the&#xA;anthropogenic fossil component. We determined that in 2018,&#xA;atmospheric anthropogenic fossil CO2 represented 23% of the total&#xA;emissions since 1750 with the remaining 77% in the exchange&#xA;reservoirs. Our results show that the percentage of the total CO2 due&#xA;to the use of fossil fuels from 1750 to 2018 increased from 0% in 1750&#xA;to 12% in 2018, much too low to be the cause of global warming.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Fossil &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; will be essentially depleted of &lt;span class=&quot;math-container&quot;&gt;$^{14}\ce{C}$&lt;/span&gt; as it has been in the lithosphere for millions of years, far longer than the half-life of &lt;span class=&quot;math-container&quot;&gt;$^{14}\ce{C}$&lt;/span&gt;, so obviously fossil fuel emissions will have had an effect on the &lt;em&gt;relative&lt;/em&gt; concentrations of 14C in the atmosphere.  However, that is likely obscured by the &lt;span class=&quot;math-container&quot;&gt;$^{14}\ce{C}$&lt;/span&gt; from nuclear testing in the 1950s and 60s.  Also when &lt;span class=&quot;math-container&quot;&gt;$^{14}\ce{C}$&lt;/span&gt; is removed from the atmosphere, the amount of CO2 has not been reduced, it is just that the &lt;span class=&quot;math-container&quot;&gt;$^{14}\ce{C}$&lt;/span&gt; from the atmosphere has been exchanged with &lt;span class=&quot;math-container&quot;&gt;$\ce{C}$&lt;/span&gt; from the other reservoirs, at the mixing ratio found in those reservoirs.  This means it is more informative of the residence time (the average time a molecule of CO2 remains in the atmosphere before being exchanged) than the adjustment time (the time scale on which atmospheric &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; decays towards it's equilibrium value).&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\color{red}{\star}$&lt;/span&gt; Is it possible to reliably infer the anthropogenic contribution to the post-industrial rise in atmospheric &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; from &lt;span class=&quot;math-container&quot;&gt;$^{14}\ce{C}$&lt;/span&gt; observations?&lt;/p&gt;&#xA;&lt;p&gt;A reference to a paper where this is demonstrated would be greatly appreciated!&lt;/p&gt;&#xA;" OwnerUserId="624" LastEditorUserId="6129" LastEditDate="2022-05-15T13:35:00.217" LastActivityDate="2022-05-24T10:42:36.927" Title="Is it possible to reliably infer the anthropogenic contribution to the post-industrial rise in $\ce{CO2}$ from $^{14}\ce{C}$ observations?" Tags="|climate-change|carbon-cycle|anthropogenic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23812" PostTypeId="1" CreationDate="2022-05-14T21:59:00.450" Score="12" ViewCount="4364" Body="&lt;p&gt;This question came to me after reading H.P. Lovecraft's &amp;quot;Dagon&amp;quot;- the protagonist has fallen asleep drifting on the ocean in a small boat. He wakes up one morning to discover he's been grounded on what appears to be a vast region of mire that used to be the ocean floor, which had very suddenly risen to the surface:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Through some unprecedented volcanic upheaval, a portion of the ocean&#xA;floor must have been thrown to the surface, exposing regions which for&#xA;innumerable millions of years had lain hidden under unfathomable&#xA;watery depths. So great was the extent of the new land which had risen&#xA;beneath me, that I could not detect the faintest noise of the surging&#xA;ocean, strain my ears as I might. Nor were there any sea-fowl to prey&#xA;upon the dead things. [...] The region was putrid with the carcasses&#xA;of decaying fish, and of other less describable things which I saw&#xA;protruding from the nasty mud of the unending plain.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This seems to indicate that some enormous geological activity of vague nature resulted in part of the sea floor itself being thrust up to the surface in what can only be assumed to be the sudden formation of a large new island. This activity is implied to have happened without anyone knowing about it (until now).&lt;/p&gt;&#xA;&lt;p&gt;I know very little about oceanic geology, and the plausibility of this whole thing confuses me. Is it possible for the ocean floor itself to be pushed up above the water? Is it possible for this, or any other process of land formation, to occur so fast as to leave marine life stranded on the now-surface? Lastly, is it possible for such geologic activity to occur unnoticed by humans?&lt;/p&gt;&#xA;" OwnerUserId="26846" LastEditorUserId="26866" LastEditDate="2022-05-17T20:18:10.577" LastActivityDate="2022-06-11T23:39:43.823" Title="How plausible is it that &quot;a portion of the ocean's floor&quot; could suddenly be &quot;thrown up to the surface&quot; as described in this Lovecraft story?" Tags="|geology|oceanography|volcanology|geodynamics|islands|" AnswerCount="4" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23813" PostTypeId="1" CreationDate="2022-05-15T00:13:03.470" Score="6" ViewCount="687" Body="&lt;p&gt;&lt;a href=&quot;https://astronomy.stackexchange.com/a/28286/7982&quot;&gt;This answer to &lt;em&gt;What is the nature of &amp;quot;rock vapor&amp;quot; in this description of the formation of the Moon?&lt;/em&gt;&lt;/a&gt; explains what &amp;quot;rock vapor&amp;quot; is and how scientists use the concept to understand planetary and in this case The Moon's formation as well.&lt;/p&gt;&#xA;&lt;p&gt;Turning rock into vapor in a controlled way in order to study how it cools and the chemical reactions that take place and the types and nature of materials that reform sounds like quite a technical challenge, but probably necessary to at least test or calibrate simulations of the process on a large scale.&lt;/p&gt;&#xA;&lt;p&gt;So I'd like to ask:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt;  Do scientists ever make rock vapor in a laboratory? If so, is it ever used to study planetary or lunar formation?&lt;/p&gt;&#xA;&lt;p&gt;If the answer to the first part is yes, answers that discuss other and perhaps more fundamental experiments done with rock vapor are certainly welcome!&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2022-05-15T01:46:06.303" LastActivityDate="2022-05-16T03:18:05.253" Title="Do scientists ever make rock vapor in a laboratory? If so, is it ever used to study planetary or lunar formation?" Tags="|geochemistry|planetary-science|planetary-formation|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23814" PostTypeId="1" CreationDate="2022-05-15T00:28:15.480" Score="1" ViewCount="115" Body="&lt;p&gt;In the process of drilling holes in the ground, if water was introduced, could it reach equilibrium vapor pressure, flash to steam and expel drill bit, drilling rod, and other debris up and out of the opening at potentially very high velocities?&lt;/p&gt;&#xA;&lt;p&gt;I have seen videos showing drilling rigs penetrating chambers, such as salt domes, that were highly pressurized by various gases resulting in quite violent expulsions of water, drilling mud, rock, and most frighteningly, great lengths of drilling rod and drill bit assemblies; literally tons of such material hundreds of feet into the air through the small diameter bore hole, destroying the derrick, and accompanied by a tremendous ground-shaking felt hundreds of feet in all directions,along with a roaring sound rivaling that of a rocket launch, but sometimes occurring decades before a rocket launch was even imagined.&lt;/p&gt;&#xA;" OwnerUserId="26847" LastEditorUserId="6129" LastEditDate="2022-05-16T03:56:51.057" LastActivityDate="2022-05-16T03:56:51.057" Title="Formation of steam underground" Tags="|water|geothermal-heat|drilling|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23815" PostTypeId="2" ParentId="23812" CreationDate="2022-05-15T01:19:28.963" Score="13" Body="&lt;p&gt;Generally the Earth's geology moves very slowly, ... very slowly. When people use the term &lt;em&gt;geological time scales&lt;/em&gt; they mean a very long period of time, usually in the millions of years. In volcanic regions with very shallow water, volcanic activity might raise a small fragment of the sea bed above the water. Other than that, such movements don't happen.&lt;/p&gt;&#xA;&lt;p&gt;Firstly, the forces required to do would be immense and explosive. It would also have the potential to create a tsunami by putting so much energy into to water. Secondly, the fragment of the sea bed raised in such a manner would need to be supported by rock from underneath. It would need a foundation to rest upon.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-05-15T01:19:28.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23816" PostTypeId="2" ParentId="23814" CreationDate="2022-05-15T01:36:19.073" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;In the process of drilling holes in the ground, if water was introduced, could it reach equilibrium vapor pressure, flash to steam and expel drill bit, drilling rod, and other debris up and out of the opening at potentially very high velocities?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;No!&lt;/p&gt;&#xA;&lt;p&gt;Depending on the type of hole being drilling and its length, water can sometimes be added during the drilling process to suppress dust produced when drilling rock. Also, the impact forces for hammering action drill bits are not enough to suddenly turn any water in the drill hole into steam that will catastrophically destroy the drill rig and associated equipment. Also, not all drill rigs use a hammering (percussive) action when drilling holes. Some use just a percussive action, others both a percussive and rotary action, while other use just a rotary action.&lt;/p&gt;&#xA;&lt;p&gt;Catastrophic destruction of a drill rig and ejection of a drill steel only occurs when a high pressure environment is encountered during the course of drilling. Gas, oil or water under pressure underground can be catastrophically destructive when the high pressure environment is pierced and the pressurized fluid is released through a narrow diameter hole.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-05-15T01:36:19.073" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23817" PostTypeId="2" ParentId="23813" CreationDate="2022-05-15T11:41:51.097" Score="8" Body="&lt;p&gt;Not quite &amp;quot;rock vapour&amp;quot;, but scientists do study gas-rock interactions. Some of that is used to understand processes forming in the moon.&lt;/p&gt;&#xA;&lt;p&gt;For example, &lt;a href=&quot;https://doi.org/10.1016/j.gca.2017.03.012&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt; looked at volatile metals (zinc, lead, etc) and their behaviour in a gaseous phase (aka vapour) when in equilibrium with solid rocks and liquids. Their temperature was as high as 1500 °C and they used that to understand the formation and compositions of glassy blobs found on the Moon's surface by the Apollo missions.&lt;/p&gt;&#xA;&lt;p&gt;Another example is &lt;a href=&quot;https://doi.org/10.1038/nature23645&quot; rel=&quot;nofollow noreferrer&quot;&gt;this other paper&lt;/a&gt; which looks at the condensation sequence of moderately volatile elements. Their experiments went up to 1700 °C.&lt;/p&gt;&#xA;&lt;p&gt;Note that all those experiments were vaporised moderately volatile metals - things that would be gaseous at the temperatures attainable in experimental apparatuses. 1700 °C is pretty much the highest you can get, and even that requires specialised equipment. Anything hotter that will allow &amp;quot;true&amp;quot; vaporised rock is simply impossible. One solution might be to use a levitating droplet heated with laser, but these experiments are usually held in a stream of gas so any vapour would immediately be removed before it can be studied.&lt;/p&gt;&#xA;" OwnerUserId="725" LastEditorUserId="725" LastEditDate="2022-05-16T03:18:05.253" LastActivityDate="2022-05-16T03:18:05.253" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23818" PostTypeId="2" ParentId="23812" CreationDate="2022-05-15T11:47:05.377" Score="10" Body="&lt;p&gt;Very implausible.&lt;/p&gt;&#xA;&lt;p&gt;If your sailor is actually in the middle of the ocean, there are several kilometres of water underneath. Nothing that we know of can uplift kilometres of rock overnight, at least something that will not destroy the Earth.&lt;/p&gt;&#xA;&lt;p&gt;Alternatively, your hero might be in an area where the seafloor is rather shallow, potentially several metres. These aren't necessarily rare. Some parts of the Torres Strait or the North Sea are rather shallow. An earthquake might cause some parts of it to rise several metres, just enough for it to poke above the water. However, these waters should be shallow enough for the sailor to know that it's shallow, and not &amp;quot;in the middle of the ocean&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;A third option is a volcanic eruption, as these are known to create land. However, these events are rather violent and your hero is unlikely to survive this.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2022-05-15T11:47:05.377" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23820" PostTypeId="2" ParentId="23812" CreationDate="2022-05-15T16:24:39.633" Score="2" Body="&lt;p&gt;The rock on the ocean floor is not likely to well up to the surface anytime soon. &lt;a href=&quot;https://phys.org/news/2017-06-domes-frozen-methane-blow-outs.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;But methane can.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Methane, formed from biological processes or decay of organic matter at sea bottoms, forms water-ice clathrates, or hydrates, in which methane under pressure combines with water to produce a solid material stable under ocean-floor conditions -- if the pressure is maintained. These hydrates may accumulate methane gas under this pressure, forming &lt;strong&gt;gas-hydrate pingoes&lt;/strong&gt; (the name is carried over from land-based pingoes, but this is a different phenomenon). The pingoes sometimes explode (&amp;quot;Ping!&amp;quot;) when some phenomenon, such as a drop in sea level, decreases the pressure and thus breaks the hydrate down. Such explosions release great volumes of greenhouse-producing methane gas and may have enough blasting force to form craters on the ocean-bottom rock below.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2022-06-11T23:39:43.823" LastActivityDate="2022-06-11T23:39:43.823" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23821" PostTypeId="1" AcceptedAnswerId="23824" CreationDate="2022-05-15T16:27:17.750" Score="2" ViewCount="441" Body="&lt;p&gt;I have been recently thinking about how the water level of Lake Mead keeps dropping due to its high water evaporation rate brought on by recent years of historical drought conditions. The continuous lowering of Lake Mead threatens to shut down Hoover Dam and also threatens the water supply for Las Vegas, since they get most of their drinking water from Lake Mead.&lt;/p&gt;&#xA;&lt;p&gt;As a short term solution to this problem, I am thinking that it might be worthwhile for the U.S. Army Corps of Engineers to start laying down long sheets of bubble wrap over the surface of Lake Mead to reduce the rate of water evaporation. Large quantities of water vapor would be trapped beneath the sheets of bubble wrap and this should reduce the amount of water lost to evaporation.&lt;/p&gt;&#xA;&lt;p&gt;I am sure large amounts of bubble wrap could be quickly manufactured especially if the U.S. government were to subsidize bubble wrap manufacturers around the nation, and if they also were to pay for the transport of this bubble wrap from these factories to Lake Mead. The U.S government could also pay for the costs of ships and crews deploying the bubble wrap out on the lake.&lt;/p&gt;&#xA;&lt;p&gt;Lake Mead is 247 square miles in size and it may be too expensive to cover all of its surface with sheets of bubble wrap. Yet, even if say only 33% of the lake's surface could be covered, this should still have a significant impact on reducing the amount of water lost to evaporation.&lt;/p&gt;&#xA;&lt;p&gt;Once the drought comes to an end and the water level on Lake Mead has risen back to its normal level, then these ships would go back out on the lake to collect the bubble wrap and it could be stored in warehouses for future use if the need for it arise again.&lt;/p&gt;&#xA;&lt;p&gt;Would covering part of Lake Mead with large sheets of bubble wrap reduce the amount of water lost to evaporation?&lt;/p&gt;&#xA;" OwnerUserId="23275" LastEditorUserId="23275" LastEditDate="2022-05-15T20:44:36.413" LastActivityDate="2024-03-05T19:08:48.950" Title="Would covering part of Lake Mead with large sheets of bubble wrap reduce the amount of water lost to evaporation?" Tags="|climate-change|hydrology|water|geoengineering|water-vapour|" AnswerCount="2" CommentCount="17" ContentLicense="CC BY-SA 4.0" />
  <row Id="23822" PostTypeId="2" ParentId="23814" CreationDate="2022-05-15T17:26:19.793" Score="0" Body="&lt;p&gt;What is you point ? And , it is nat gas pressure primarily, although there may be a little steam. The BP accident ( ? Horizon) in the Gulf of Mexico a few years ago was a nat gas blowout. Drillers routinely go for a short course refresher with new developments on gas kicks (what you are describing). A gas kick is the nemesis of deep drilling. Pressures can exceed 25,000 psi. At that pressure ,the gas cannot be seen on seismic because it is so dense. A primary tool is measuring mud volume into the hole and mud volume out of the hole; they need to match. It is drill pipe not rod. Salt domes are usually not deep enough to have the serious pressures that can cause a blowout. Actually salt domes are usually the opposite problem; a hole is accidently made into a low pressure volume. There is always water in a gas/oil well ; steam pressure is not a problem.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastEditorUserId="8409" LastEditDate="2022-05-16T00:01:10.377" LastActivityDate="2022-05-16T00:01:10.377" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23823" PostTypeId="2" ParentId="23812" CreationDate="2022-05-16T08:38:43.637" Score="3" Body="&lt;p&gt;Putting a piece of oceanic crust on land is an existing geological process called &lt;a href=&quot;https://en.wikipedia.org/wiki/Obduction&quot; rel=&quot;nofollow noreferrer&quot;&gt;obduction&lt;/a&gt;. However, it is not a sudden process, but rather a very slow one.&lt;/p&gt;&#xA;&lt;p&gt;Now, there is one process that can lift the ground quite rapidly: &lt;a href=&quot;https://en.wikipedia.org/wiki/Bradyseism&quot; rel=&quot;nofollow noreferrer&quot;&gt;bradyseism&lt;/a&gt;. It occurs at volcanic calderas, the best documented example being the bradyseismic activity of the Campi Flegrei caldera near Naples. The mechanisms of bradyseism are still debated (there are various models trying to explain the phenomenon), but it results in alternating phases of ground uplift and subsidence.&lt;/p&gt;&#xA;&lt;p&gt;In the twentieth century, there has been two episodes of uplift in Campi Flegrei (&lt;a href=&quot;https://doi.org/10.1016/S0377-0273(99)00050-5&quot; rel=&quot;nofollow noreferrer&quot;&gt;Orsi et al., 1999&lt;/a&gt;): one in 1969&lt;span class=&quot;math-container&quot;&gt;$-$&lt;/span&gt;1972 (1.74 m of vertical displacement), another one in 1982&lt;span class=&quot;math-container&quot;&gt;$-$&lt;/span&gt;1984 (1.79 m of vertical displacement). Both episodes showed an average rate of about 1.4 mm/day. In terms of geological timescales, this is super fast. But not quite as &amp;quot;sudden&amp;quot; as what you are looking for... But wait, there's more!&lt;/p&gt;&#xA;&lt;p&gt;In the past, there has been more intense uplift episodes in the Campi Flegrei caldera, although for those we don't have ground displacement measurements, only historical chronicles. &lt;a href=&quot;https://doi.org/10.1007/s00445-010-0430-3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Guidoboni &amp;amp; Ciuccarelli (2011)&lt;/a&gt; mention at least three episodes where major uplift caused new land to emerge from the sea:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;In an edict dated from October 6, 1503, the town of Pozzuoli was granted an area of &amp;quot;dried-up sea&amp;quot; (&lt;em&gt;marem desiccatum&lt;/em&gt;).&lt;/li&gt;&#xA;&lt;li&gt;In a similar edict from May 23, 1511, the town of Pozzuoli was granted another area of &amp;quot;dried-up sea&amp;quot;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The extent of the uplift was such that a quantity of land emerged on&#xA;which human activities could take place. The area, previously occupied&#xA;by the sea, was requested by the inhabitants of Pozzuoli for the&#xA;building of new houses and buildings, because their villages had&#xA;mostly collapsed or become uninhabitable due to the repeated&#xA;earthquakes of previous years.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The last, and most known episode, occurred on September 28, 1538, hours before the Monte Nuovo eruption:&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Uplift from the seabed in the area between Lake Averno and Monte&#xA;Barbaro (ca. 2.5 km). The sources report that this uplift produced a&#xA;considerable quantity of dead fish in a kind of shoal. It is very&#xA;likely that this involved a rapid movement, although the sudden death&#xA;of the fish which were brought to the surface could also be due to&#xA;other causes (such as a rapid variation of temperature, or infusion of&#xA;gas?). This uplift was not described in the sources as such, but&#xA;rather as a drying up of the sea, and was interpreted by naturalists&#xA;at the time as the result of a rapid absorption of sea water by the&#xA;seabed.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;There you go, dead fish and all, just like in Lovecraft!&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2022-05-16T08:38:43.637" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23824" PostTypeId="2" ParentId="23821" CreationDate="2022-05-16T21:25:24.533" Score="9" Body="&lt;p&gt;Something similar has been done &lt;a href=&quot;https://www.pbs.org/newshour/science/why-96-million-plastic-shade-balls-dumped-into-the-la-reservoir-may-not-save-water&quot; rel=&quot;nofollow noreferrer&quot;&gt;with plastic balls&lt;/a&gt;.  I'd guess they're much easier to manufacture, since it doesn't have to be a continuous sheet.  It sounds like there is some local water savings, and the time to outweigh the manufacturing water use isn't a huge concern in this context.&lt;/p&gt;&#xA;&lt;p&gt;Edit: that's evidently not why they have the balls there, but they do say it can reduce evaporation by 85-90% nevertheless.&lt;/p&gt;&#xA;&lt;p&gt;That being said, I'm not sure what the cost vs benefit would look like.  The highest possible value--likely much higher than realistic--for reduced evaporation would be about one-seventh of a very low estimate of the inflow.  The losses are dominated by actual use, not evaporation.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Discharge from &lt;a href=&quot;https://waterdata.usgs.gov/monitoring-location/09404200/#parameterCode=00060&amp;amp;period=P365D&quot; rel=&quot;nofollow noreferrer&quot;&gt;a Colorado River gage not far upstream of Lake Mead&lt;/a&gt; seems to typically be in the range of 10,000-15,000 cfs (about 280 cms at the low end).  Not accounting for any inflows between that gage and Lake Mead, so that's a doubly low estimate.&lt;/li&gt;&#xA;&lt;li&gt;Mean annual potential evapotranspiration from Water Years 2010-2019 (from &lt;a href=&quot;https://developers.google.com/earth-engine/datasets/catalog/IDAHO_EPSCOR_TERRACLIMATE#bands&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;) at Lake Mead seems to be about 2 m.  If the lake's evaporation was exactly equal to that maximum, and &lt;em&gt;all&lt;/em&gt; of it was stopped by the covering, then this would equate to about 40 cms, on average.  (That's a remote sensing estimate, so I'm not sure how accurate it is over a large water body; I know some algorithms struggle with that.)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="26713" LastEditorUserId="26713" LastEditDate="2024-03-05T19:08:48.950" LastActivityDate="2024-03-05T19:08:48.950" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23826" PostTypeId="1" CreationDate="2022-05-17T13:35:22.140" Score="1" ViewCount="26" Body="&lt;p&gt;I am in the process of creating an isoscape for the stable isotopes in precipitation (&lt;sup&gt;2&lt;/sup&gt;H and &lt;sup&gt;18&lt;/sup&gt;O). Does anyone know of any other databases besides GNIP (IAEA) that have further entries (especially measured values for the period around 1950 to 1970)?&lt;/p&gt;&#xA;&lt;p&gt;I know there is also the Bowen database: &lt;a href=&quot;https://wateriso.utah.edu/waterisotopes/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://wateriso.utah.edu/waterisotopes/&lt;/a&gt;&#xA;but here I don't understand if it is possible to get the actual data.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="18081" LastEditDate="2022-05-17T20:26:10.433" LastActivityDate="2022-05-17T20:26:10.433" Title="Data for Isoscape" Tags="|open-data|mapping|database|isotopic|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23827" PostTypeId="2" ParentId="9161" CreationDate="2022-05-19T16:21:12.473" Score="4" Body="&lt;p&gt;The vadose zone can be on the order of meters, depending on the soil type (higher with finer soils).  The maximum height of capillary rise (&lt;span class=&quot;math-container&quot;&gt;$h_c$&lt;/span&gt;) occurs where capillary suction head is equal to the elevation head above the water table.&lt;/p&gt;&#xA;&lt;p&gt;In a capillary tube with diameter &lt;span class=&quot;math-container&quot;&gt;$d$&lt;/span&gt;, and where water has surface tension &lt;span class=&quot;math-container&quot;&gt;$T_s$&lt;/span&gt;, a zero contact angle, and unit weight &lt;span class=&quot;math-container&quot;&gt;$\gamma$&lt;/span&gt;, then the maximum capillary rise is &lt;span class=&quot;math-container&quot;&gt;$h_c=\frac{4T_s}{d\gamma}$&lt;/span&gt; (Lu and Likos 2004).&lt;/p&gt;&#xA;&lt;p&gt;Some empirical studies compiled in Lu and Likos (2004) Table 4.1 have found maximum capillary rises in various soils as high as 360 cm (95% silt/clay from Lane and Washburn (1946)).  That being said, in such soils the plant would not be able to get the water at a large &lt;em&gt;rate&lt;/em&gt;, since the hydraulic conductivity is very low.&lt;/p&gt;&#xA;&lt;p&gt;Reference: Lu, Ning and Likos, William J. (2004). &lt;em&gt;Unsaturated Soil Mechanics&lt;/em&gt;.&lt;/p&gt;&#xA;" OwnerUserId="26713" LastActivityDate="2022-05-19T16:21:12.473" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23828" PostTypeId="1" AcceptedAnswerId="23833" CreationDate="2022-05-19T20:35:38.360" Score="6" ViewCount="108" Body="&lt;p&gt;I saw this interesting graphic (&lt;a href=&quot;https://www.visualcapitalist.com/worlds-25-largest-lakes/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The World’s 25 Largest Lakes, Side by Side&lt;/a&gt;) of some of the largest lakes in the world.&lt;/p&gt;&#xA;&lt;p&gt;It strikes me as somewhat curious that most of the lakes have a high eccentricity - that is, they appear to have a &amp;quot;length&amp;quot; at least three times more than a &amp;quot;width&amp;quot;.  An exception in the image may be Lake Victoria, which has a somewhat circular shape.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Is this observation a coincidence, a conclusion based on too small a sample size, or could this be related to how the lakes were formed?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I'd guess that Erie and Michigan were formed roughly at the same time - both have a high degree of eccentricity, but Michigan is oriented more north-south while Erie is diagonally oriented to the northeast.&lt;/p&gt;&#xA;&lt;p&gt;Naively I would expect lake formation to be mostly isotropic - leading to circular shapes.&lt;/p&gt;&#xA;&lt;p&gt;The question was born out of curiosity.  This conflicted a little with my intuition - for example many features on Earth, such as tectonic plates or many large islands such as Hokkaido or Madagascar, have very &lt;a href=&quot;https://en.wikipedia.org/wiki/Shmoo&quot; rel=&quot;nofollow noreferrer&quot;&gt;&amp;quot;Schmoo&amp;quot;&lt;/a&gt; shapes, so my first guess would be &amp;quot;why not lakes?&amp;quot;  I also recall the dictum that &amp;quot;nature abhors straight lines&amp;quot; - but Loch Ness is pretty straight.&lt;/p&gt;&#xA;&lt;p&gt;Nonetheless I recall or guess that many lakes such as the (North American) Great Lakes were formed from the recession of glaciers.  The &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia article&lt;/a&gt; lists many different kinds of lakes - most of those do have some eccentricity.  It's perhaps somewhat interesting that many of the processes of forming lakes are associated with high eccentricity.&lt;/p&gt;&#xA;" OwnerUserId="26889" LastEditorUserId="81" LastEditDate="2022-05-20T15:23:01.480" LastActivityDate="2022-05-20T17:59:58.467" Title="Do lakes tend to have elliptical shapes more often than circular shapes?" Tags="|geomorphology|lakes|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23832" PostTypeId="2" ParentId="23808" CreationDate="2022-05-20T13:44:52.163" Score="0" Body="&lt;p&gt;Ok I think there is no similar package. Therefore, the best approach is to do the interpolation with the package Pykrige and for displaying the data I would recommend the package Basemap (unfortunately, I have not used catropy, but I can say that Basemap is well usable even by non-Python affine users).&#xA;Good Luck&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2022-05-20T13:44:52.163" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23833" PostTypeId="2" ParentId="23828" CreationDate="2022-05-20T15:03:38.350" Score="5" Body="&lt;p&gt;I can think of six main types of lake regimes based on the environment in which they form and exist (this is a generalisation). In the comments to the question it is mentioned lakes in formerly glaciated areas and lakes formed by tectonic activity such as the African rift. A more rare and perhaps spectacular form come from meteorite impacts. To those I would add lakes related to volcanism, lakes formed in karst terrain and thermokarst lakes formed in permafrost and glacial environments.&lt;/p&gt;&#xA;&lt;p&gt;Glacially formed lakes are caused by either excavation of valleys to form troughs in which lakes form or by damming of water from glacial deposits. In the case of troughs they definitely are highly eccentric to use the terminology of the question. However, lakes dammed by glacial deposits may have various shapes depending on the terrain upstream of the damming. The damming may of course occur in valleys which again results in eccentric lakes. But local topography will in the end determine the lake fom.&lt;/p&gt;&#xA;&lt;p&gt;Lakes caused by tectonic activity, such as in the extensional regime of the African rift will be laterally constrained by the rift walls and thus primarily also eccentric. Again, it will be the shape of the terrain that decides the shape so with linear tectonic land forms lakes will probably tend to be eccentric.&lt;/p&gt;&#xA;&lt;p&gt;Volcanic lakes, on the other hand, probably tend to be more circular in shape since they form in calderas, maars or volcanic craters, all of which are more circular shapes. Some examples include Mono Lake (USA), Pulvermaar (Germany) and Laguna de Quiltoa (Ecuador).&lt;/p&gt;&#xA;&lt;p&gt;In karst terrain lakes may form from collapse of caves forming water filled sink holes such as Crveno Jezero (Croatia). These are often more circular in shape due to the collapse structure.&lt;/p&gt;&#xA;&lt;p&gt;The final environment is the cryospheric regions where frozen ground thaws and creates depressions that fill with water. The depressions largely grow radially due to the heat captured by the water of the lake &amp;quot;eating&amp;quot; into the sides of the lake. These types of lakes are common place in Alaska, northern Canada and northern Russia and easily found by a quick browse in Google Earth.&lt;/p&gt;&#xA;&lt;p&gt;Impact craters form more or less circular lakes if they fill up with water such as Lonar Lake (India). However, sometimes the centre of the impact is uplifted leaving lakes that form a ring such as in the case of Lake Manicougan (Canada) and Lake Siljan (Sweden).&lt;/p&gt;&#xA;&lt;p&gt;I am sure one could add more instances where lakes form but in general you need a depression formed either by erosion or tectonics or a damming caused either by deposition or, again, tectonics to form a lake.&lt;/p&gt;&#xA;&lt;p&gt;So to sum up, the form of lakes depends on the environment in which they appear and the processes involved in shaping the topography. In the case of the comparison mentioned in the questions, the lakes presented (one sea) are all very large and may not be representative for all lakes in the world.&lt;/p&gt;&#xA;&lt;p&gt;There is no strict definition as to the lower limit to what is considered a lake which makes it difficult to assess all the smaller lakes, particularly thermokarst lakes.&lt;/p&gt;&#xA;&lt;p&gt;Use e.g. Google Earth to visit the sites mentioned in the text.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="81" LastEditDate="2022-05-20T17:59:58.467" LastActivityDate="2022-05-20T17:59:58.467" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23834" PostTypeId="1" CreationDate="2022-05-20T18:27:41.090" Score="4" ViewCount="30" Body="&lt;p&gt;Yesterday, we performed a sediment sampling along both sides of a river. On various research papers, it seems that they always made it successfully to perform the sampling at both left and right side of the river on a single site, meanwhile in my case, it is quite impossible to me to sample the opposite side of the river on same site because it has a very steep angle and on other site there was a big excavator digging up those sediments on one side. The sampling relied mostly on the muddy, but accessible, flood sediment deposits. There was no previous study related to the river I performed at so I have no previous information regarding the nature of the deposits on each side.&lt;/p&gt;&#xA;&lt;p&gt;At the end, I performed the sampling like this:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/N5IbV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/N5IbV.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I was asked to perform the sampling at both left and right side of the river (without any detail here) and those sediments will be acid-digested and its heavy metal concentrations will be measured using an atomic absorption spectrophotometer.&lt;/p&gt;&#xA;&lt;p&gt;Is this sampling acceptable? Is there any reference that this sampling is acceptable or not, considering that struggles before?&lt;/p&gt;&#xA;&lt;p&gt;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="26891" LastEditorUserId="26891" LastEditDate="2022-05-20T18:34:03.890" LastActivityDate="2022-05-20T18:34:03.890" Title="Is this kind of sediment location sampling on river acceptable?" Tags="|geochemistry|sedimentology|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23835" PostTypeId="1" CreationDate="2022-05-21T02:55:23.570" Score="1" ViewCount="17" Body="&lt;p&gt;Toxicity characteristic leaching procedure (TCLP) is an extraction method to simulate a soil or sediment leaching. The method employed two extraction fluids - one is a buffered&#xA;solution of acetic acid and sodium hydroxide while the another one is an unbuffered acetic acid solution. [1] Although this protocol is widely used by many government instances, I still can not find any meaningful justification on whether first solution should and should not be able to thoroughly leach a sodiment or soil. I also can not find any theoretical, computational, or spectroscopic basis that can explain the mechanism behind the dissolution of such soils by unbuffered and buffered solutions, let it be a common ferrihydrite or goethite soil. Could there be any evidence that it might transform into an unstable hydroxide-hydrate-acetate ferrihydrite species?&lt;/p&gt;&#xA;&lt;p&gt;Any insight &lt;strong&gt;from research article&lt;/strong&gt; is appreciated and please do not put simple textbook explanations. Thank you very much.&lt;/p&gt;&#xA;&lt;p&gt;[1] &lt;a href=&quot;https://www.epa.gov/sites/default/files/2015-12/documents/1311.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.epa.gov/sites/default/files/2015-12/documents/1311.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26891" LastActivityDate="2022-05-21T02:55:23.570" Title="What chemical or physical parameters altered during the usage of buffered versus unbuffered extractant for leachability of a soil or sediment?" Tags="|geochemistry|sedimentology|soil-science|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23836" PostTypeId="1" CreationDate="2022-05-21T08:49:43.933" Score="2" ViewCount="49" Body="&lt;p&gt;I am trying to design a cost and energy efficient aerial survey and have come up against the question, 'do we have to fly straight lines perpenducular to geology?' as not doing so could make for a more energy efficient program.&lt;/p&gt;&#xA;&lt;p&gt;Does anyone have a good explanation on why geophysical surveys (particularly aeromag) are flown in parallel lines perpendicular to known features?&lt;/p&gt;&#xA;&lt;p&gt;Is there any reason why you couldn't fly your survey along Topographic contours where terrain is very steep and undulating to reduce the energy requirements on your survey?&lt;/p&gt;&#xA;" OwnerUserId="26893" LastEditorUserId="26893" LastEditDate="2022-05-22T07:18:12.560" LastActivityDate="2022-05-22T07:18:12.560" Title="Airborne geophysical survey in steep and undulating terrain. What is more important, energy conservation or orienting lines wrt to geology and why?" Tags="|geology|geophysics|minerals|geomagnetism|mining|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23837" PostTypeId="1" CreationDate="2022-05-21T10:28:44.650" Score="2" ViewCount="198" Body="&lt;p&gt;I saw one way to achieve this using the magnetotelluric way, but I need some solid fundamental way to understand it. Any book recommendations would be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="26894" LastEditorUserId="6129" LastEditDate="2022-05-21T17:41:00.133" LastActivityDate="2023-06-14T12:02:23.883" Title="Ways of detecting underground bodies of water" Tags="|geophysics|water|underground-water|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23839" PostTypeId="1" AcceptedAnswerId="23842" CreationDate="2022-05-23T12:55:10.380" Score="1" ViewCount="1365" Body="&lt;p&gt;I was wondering which programming language is most used in the geosciences? I have now started programming with Python but I am reading more and more about R! I would like to ask the experienced scientists which language they use and especially why? I would also like to know if there is a general consensus on this question in the climate and earth science community!&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-06-07T06:42:10.640" LastActivityDate="2022-06-07T06:42:10.640" Title="Python, R or etc.?" Tags="|climate-models|atmosphere-modelling|python|r|" AnswerCount="3" CommentCount="7" FavoriteCount="0" ClosedDate="2022-05-31T12:36:25.050" ContentLicense="CC BY-SA 4.0" />
  <row Id="23840" PostTypeId="2" ParentId="23839" CreationDate="2022-05-23T18:05:18.513" Score="4" Body="&lt;p&gt;Essentially there is no consensus. To some degree it comes down to personal preference but it also depends on the application - what needs to be done.&lt;/p&gt;&#xA;&lt;p&gt;Python is a very popular language and for smaller scale scientific usage it is a good language. The main negative concerning Python is it's speed of processing. Its speed of calculation is &lt;strong&gt;slow&lt;/strong&gt;. If you have a large data set or need to perform complex calculations, I would not recommend Python. Python is a good language for proof of concept purposes or small tasks. For larger data sets or for complex calculations, a faster language is required. Weather forecast modeling is not done using Python.&lt;/p&gt;&#xA;&lt;p&gt;In some situations Fortran is still used. Despite its age and most people complaining about its style of programming, it still has applications. Failing that, heavy duty computations are sometimes done using C or C++.&lt;/p&gt;&#xA;&lt;p&gt;Complied languages tend to be faster than interpreted languages. A newer, scientifically orientated, language which is generating interest is Julia. It's slightly slower than Fortran and C, but &lt;em&gt;much&lt;/em&gt; faster than Python.&lt;/p&gt;&#xA;&lt;p&gt;The R language was initially written as a statistics analysis package, and that is still its forte.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;a href=&quot;https://jonathankinlay.com/2018/10/comparison-programming-languages/&quot; rel=&quot;nofollow noreferrer&quot;&gt;A Comparison of Programming Languages&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;a href=&quot;https://stackoverflow.com/questions/64300405/speed-in-matlab-vs-julia-vs-fortran&quot;&gt;Speed in Matlab vs. Julia vs. Fortran&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2022-05-23T22:50:31.980" LastActivityDate="2022-05-23T22:50:31.980" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23842" PostTypeId="2" ParentId="23839" CreationDate="2022-05-24T01:40:13.163" Score="6" Body="&lt;p&gt;In my opinion, python is a more established global language that is used by many more disciplines/users, compared to R. This can be advantageous because examples/tutorials are everywhere and you can accomplish many programmatic tasks in one environment. On the other hand, R has a very strong user-base that is specific to data analysis and display.  So, most of the users are in science or math disciplines and know how to get those tasks done well.  Specific to geosciences, python has historically been linked to GIS work, which is an important legacy.  The python packages (e.g. geopandas) handle GIS work very easily and quickly.  But, if you want to get some really nerdy display stuff done with live data, most of my colleagues would recommend R for on-the-fly calculation and display.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2022-05-24T01:40:13.163" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23843" PostTypeId="2" ParentId="23839" CreationDate="2022-05-24T05:08:22.080" Score="5" Body="&lt;p&gt;Python implemented weather models also exist - &lt;a href=&quot;https://github.com/ai2cm/pace&quot; rel=&quot;nofollow noreferrer&quot;&gt;PACE Weather Model&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I am going to take a slightly different view than the other answers. For weather forecasting models  Fortran 2018 with it's strong HPC links is the best solution out there.&lt;/p&gt;&#xA;&lt;p&gt;But what about post analysis of data ? Here due to the easy availability of libraries such as numpy and scipy(and well tested as well) python is the best alternative out there. No doubt such alternatives do exist in the R world too but I have just not seen any large scale adoption of that language in the meteorological community. Thre is an AMC &lt;a href=&quot;https://annual.ametsoc.org/index.cfm/2022/program-events/conferences-and-symposia/12th-symposium-on-advances-in-modeling-and-analysis-using-python/&quot; rel=&quot;nofollow noreferrer&quot;&gt;AMC Annual Python Conference&lt;/a&gt; dedicated to advances using python language.&lt;/p&gt;&#xA;&lt;p&gt;Finally from a personal perspective existing libraries that deal with weather model code (finite differences or spectral models such as GEMPAK or SPHEREPACK) are in fortran. But an individual  researcher can easily use a utility such as f2py to combine the best of both languages and incorporate these libraries into their work.&lt;/p&gt;&#xA;&lt;p&gt;In fact the libraries numpy and scipy themselves use C and the Cython interface to speed their libraries.&lt;/p&gt;&#xA;" OwnerDisplayName="user1066" LastEditorDisplayName="user1066" LastEditDate="2022-05-25T01:31:40.363" LastActivityDate="2022-05-25T01:31:40.363" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23844" PostTypeId="2" ParentId="23811" CreationDate="2022-05-24T10:42:36.927" Score="3" Body="&lt;p&gt;The NOAA has used carbon-14 to identify &lt;em&gt;local sources&lt;/em&gt; of anthropogenic carbon dioxide, which would suffer less interference from  factors acting elsewhere around the globe, such as nuclear testing. The map below, showing yellow and red areas where the near-surface atmosphere is depleted of carbon-14, matches with the most densely populated and heavily industrialized areas of North America.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://research.noaa.gov/article/ArtMID/587/ArticleID/2631/Fingerprinting-fossil-fuel-emissions-with-carbon-14&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reference and figure source&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Gz5At.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Gz5At.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2022-05-24T10:42:36.927" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23845" PostTypeId="2" ParentId="13400" CreationDate="2022-05-24T14:20:36.527" Score="0" Body="&lt;p&gt;One piece of circumstantial evidence is that climate skeptics have not been able to come up with a &lt;em&gt;physical&lt;/em&gt; model of the climate (like a GCM) that can explain both modern climate &lt;strong&gt;and&lt;/strong&gt; paleoclimate data without CO2 being a strong greenhouse gas.  Neither have they been able to tune an existing climate model (many have their source code in the public domain, and have done for decades) in a way that they can explain modern climate while equilibrium climate sensitivity of the model was low.  Believe me, they have been given that challenge more than once, but no takers so far.&lt;/p&gt;&#xA;&lt;p&gt;When you have to make a decision, you have to go with the best model you have (taking into account the uncertainties).  Prediction is difficult, especially about the future, but without a model you can only guess.&lt;/p&gt;&#xA;" OwnerUserId="624" LastEditorUserId="624" LastEditDate="2022-05-24T14:31:28.030" LastActivityDate="2022-05-24T14:31:28.030" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23847" PostTypeId="1" CreationDate="2022-05-25T00:37:44.220" Score="1" ViewCount="77" Body="&lt;p&gt;I'm working on a science fiction project and hoping someone who knows something about climate can answer this question for me: if Earth had 25% less gravity, how would that affect precipitation? I read that air at lower density holds more water vapor. Would this mean a lower gravity version of our planet would be more misty? Would it rain more?&lt;/p&gt;&#xA;" OwnerUserId="26907" LastActivityDate="2022-05-25T12:33:49.677" Title="How might 25% lower gravity affect precipitation on an Earth-like planet?" Tags="|meteorology|planetary-science|precipitation|gravity|hypothetical|" AnswerCount="1" CommentCount="7" ClosedDate="2022-05-26T00:00:02.117" ContentLicense="CC BY-SA 4.0" />
  <row Id="23848" PostTypeId="2" ParentId="23847" CreationDate="2022-05-25T12:33:49.677" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;I read that air at lower density holds more water vapor.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I suspect you may have misinterpreted what you read. Given two air masses at the same pressure and temperature but with different humidity levels, the air mass with the higher humidity level will be have a lower density than the air mass with the lower humidity. This is because &lt;span class=&quot;math-container&quot;&gt;$\ce{H_2O}$&lt;/span&gt; has a molar mass of about 18 grams/mole while nitrogen gas (&lt;span class=&quot;math-container&quot;&gt;$\ce{N_2}$&lt;/span&gt;) and oxygen gas (&lt;span class=&quot;math-container&quot;&gt;$\ce{O_2}$&lt;/span&gt;) have molar masses of about 28 grams/mole and 32 grams/mole, respectively. This difference in molar mass is what makes high humidity air less dense than low humidity air, for air masses of the same pressure and temperature.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-05-25T12:33:49.677" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23850" PostTypeId="1" CreationDate="2022-05-26T09:15:39.540" Score="4" ViewCount="78" Body="&lt;p&gt;Is the isotope fractionation that occurs during evaporation of surface water equilibrium fractionation or kinetic fractionation? I mean, evaporation can be described by Rayleigh fractionation, but I always thought that this only occurs in equilibrium fractionation. But since we can assume that the water is carried away by the wind after evaporation, can we only assume kinetic fractionation?&#xA;Does anyone have a good paper that clearly explains which fractionation process occurs during evaporation and which during condensation?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-05-27T07:05:17.320" LastActivityDate="2022-05-27T07:05:17.320" Title="Kinetic or equilibrium fractionation from 2H and 18O in evaporation and condensation?" Tags="|geochemistry|water|atmospheric-chemistry|isotopic|" AnswerCount="0" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23852" PostTypeId="1" CreationDate="2022-05-26T15:38:27.463" Score="1" ViewCount="50" Body="&lt;p&gt;For example if water falls down a waterfall then it eventually reaches the very top again to fall back down again.&lt;/p&gt;&#xA;" OwnerUserId="26915" LastActivityDate="2022-05-26T18:40:44.437" Title="What is the proper terminology for a waterfall or stream that loops back round in a cyclic manner?" Tags="|water|" AnswerCount="1" CommentCount="7" ClosedDate="2022-05-27T23:59:29.530" ContentLicense="CC BY-SA 4.0" />
  <row Id="23853" PostTypeId="1" CreationDate="2022-05-26T16:52:40.437" Score="1" ViewCount="25" Body="&lt;p&gt;I'm trying to compute something called the &amp;quot;Drying Ratio&amp;quot; following: &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2017JD027995&quot; rel=&quot;nofollow noreferrer&quot;&gt;Eidhammer, 2018&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The drying ratio is the ratio of the precipitation to the incoming vapor flux. So,&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$DR = \frac{F_{in} - F_{out}}{F_{in}} = \frac{P}{F_{in}}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;This makes some assumptions about sources/sinks (minimal evaporation for example). The vapor flux can be expressed as:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\vec{F} = \frac{-1}{g} \int_{P_{sfc}}^{P_{top}} q\vec{V}dp$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Integrating the vapor transport field along a particular control volume grid-box, and over time yields, length units (same as precipitation).&lt;/p&gt;&#xA;&lt;p&gt;When the wind component U and V are always coming from the same direction (same sign), the incoming flux into a particular control volume is found by summing up the V components for i,j and i+1, and the U components for i,j and i,j+1.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;How can this be done when the vector field changes direction?&lt;/strong&gt; In this case the opposite side of the control volume would then be the location of the incoming flux.&lt;/p&gt;&#xA;&lt;p&gt;One could go grid-cell by grid cell and find the sign of the wind direction, and then sum the incoming flux from the upwind cell using an &amp;quot;if&amp;quot; to find the direction.&lt;/p&gt;&#xA;&lt;p&gt;Is there another method? I wonder if there is a vector calc identity I am missing. This also seems like a much more general problem and I know it must be addressed in many other situations.&lt;/p&gt;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DVSeP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DVSeP.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26916" LastActivityDate="2022-05-26T16:52:40.437" Title="Compute upwind flux for gridded data" Tags="|meteorology|precipitation|fluid-dynamics|atmospheric-circulation|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23854" PostTypeId="2" ParentId="23852" CreationDate="2022-05-26T18:40:44.437" Score="2" Body="&lt;p&gt;The proper technical term is an &lt;a href=&quot;https://en.wikipedia.org/wiki/Waterfall_(M._C._Escher)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Escher &lt;em&gt;Waterval&lt;/em&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wJ2dF.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wJ2dF.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2022-05-26T18:40:44.437" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23856" PostTypeId="1" CreationDate="2022-05-26T23:20:10.127" Score="8" ViewCount="202" Body="&lt;p&gt;I am thinking (in the simplest model) that the Earth emits &lt;span class=&quot;math-container&quot;&gt;$N$&lt;/span&gt; photons per unit time, some proportion &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; hit a greenhouse gas particle and will be re-emitted back towards the earth with a probability &lt;span class=&quot;math-container&quot;&gt;$0.5$&lt;/span&gt;. Therefore the more greenhouse gas particles there are, the larger &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; will be, and the earth will heat up more.&lt;/p&gt;&#xA;&lt;p&gt;For an improved model, I'm thinking the atmosphere acts more like a continuous media with the photons bouncing around between particles and heating them. In this case, is there a simple analogy or maybe a 1 dimensional differential equation model (like heat flow through a medium)? Does heat diffusing through a material behave in a similar way as radiation propagating through the atmosphere?&lt;/p&gt;&#xA;&lt;p&gt;I am interested in simple and easy to understand and roughly accurate models for understanding greenhouse gases.&lt;/p&gt;&#xA;" OwnerUserId="26918" LastEditorUserId="26918" LastEditDate="2022-05-28T05:21:51.133" LastActivityDate="2022-05-30T16:28:41.880" Title="Is there a simple model for the interaction between greenhouse gases and infrared radiation?" Tags="|atmosphere|temperature|greenhouse-gases|thermodynamics|radiation-balance|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23857" PostTypeId="2" ParentId="6945" CreationDate="2022-05-27T04:26:55.307" Score="-1" Body="&lt;p&gt;I appreciate all of the thoughtful responses above and for the mathematical understanding that I personally would not have about this topic. One factor that may not have been considered in this discussion is the association of CO2 and water in the atmosphere and how this may have a significant affect on increasing the CO2 integration in raindrops. Another factor that must be considered is in the presence of competing organic and inorganic matter suspended in the atmosphere. Raindrops form not as a simple threshold reached between temperature,  barometric pressure and water content. We need to first differentiates free water versus bound water . In addition, we have to consider the concentration of ice nucleating Protein present on the membranes of bacteria suspended in the atmosphere. These catalysts are key in initiating the water droplet formation. Bacteria that utilize this process to return to earth are carbon fixers and also help slow evaporation. Water cycle is a part of life or better yet, it is life. Not knowing all of these specific factors and not having the mathematical knowledge I don’t think I would ever be able to figure this problem out. However, I used to live in Los Angeles. The visual  effect of a rainfall transforming smog to clear blue skies and seeing the snow capped mountains once or twice a year tells me there must be something more here.&lt;/p&gt;&#xA;" OwnerUserId="26920" LastActivityDate="2022-05-27T04:26:55.307" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23858" PostTypeId="1" CreationDate="2022-05-27T16:46:41.943" Score="4" ViewCount="486" Body="&lt;p&gt;The KT boundary was first discovered in North America at South Table Mountain near Golden, Colorado in 1943.  Supposedly, it is a dark layer 1-3 cm deep sandwiched between lighter clay.&lt;/p&gt;&#xA;&lt;p&gt;I would like to go hiking there and see the deposited boundary and take some photographs.  Could someone give me gps coordinates of where exactly the boundary is in the park?&lt;/p&gt;&#xA;" OwnerUserId="22592" LastActivityDate="2022-05-28T10:33:07.697" Title="Where can I see/photograph the KT boundary on South Table Mountain?" Tags="|mass-extinction|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23860" PostTypeId="1" CreationDate="2022-05-28T05:00:58.200" Score="1" ViewCount="528" Body="&lt;p&gt;I'm not a geologist, I am a hiker. And after many hikes in California's Sierra Nevada and Utah's red country I figured it would be great to learn some geology and I'm just posting this question to see if I can get some clarity. Obviously, I don't know what I'm talking about and my experience is limited to reading a book, so I'd very much appreciate your opinion on what I saw on a hike today.&lt;/p&gt;&#xA;&lt;p&gt;The hike was to strawberry peak (San Gabriel Mountains/Angeles National Forest) looking at rocks and wondering if someone can validate what I think they are :D&lt;/p&gt;&#xA;&lt;p&gt;I was expecting to see mostly rocks like this - I think this is granite with coarse crystals - igneous rock from down deep in the earth (hand for size reference) - I believe I have this right to call this rock granite? And also that it was formed deep in the earth in a magma chamber and pushed up in whatever episode built these mountains?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/SIuQ1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SIuQ1.jpg&quot; alt=&quot;Is this really granite?&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This also looks like granite, is that correct? What would make the layers and straight lines in this formation? The cracks I believe are from the stresses of the rock getting uplifted and surfaced but I don't know about the lines in the rock itself&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wY8VJ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wY8VJ.jpg&quot; alt=&quot;Granite?&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;What I was not expecting to see was stuff like this - which seems to me like sedimentary rock because of the layers and the fact that I could very easily pull off straight layers from it without any force at all:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EmgnL.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EmgnL.jpg&quot; alt=&quot;Sedimentary?&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Lastly there is what seems like a quartz vein inside this sedimentary(?) rock, is this just another layer of the rock or what type of process could inject quartz (or whatever this is) into the rock?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KVSBo.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KVSBo.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Thank you in advance!&lt;/p&gt;&#xA;" OwnerUserId="26925" LastActivityDate="2022-07-17T17:19:01.030" Title="Geology of the San Gabriel mountains in the Angeles national forest - rock types" Tags="|geology|rocks|mountains|igneous|orogeny|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23861" PostTypeId="2" ParentId="23858" CreationDate="2022-05-28T10:33:07.697" Score="2" Body="&lt;p&gt;According to &lt;a href=&quot;https://epod.usra.edu/blog/2013/10/cretaceous-paleogene-boundary.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cretaceous-Paleogene Boundary&lt;/a&gt; the coordinates are: &lt;a href=&quot;https://www.google.com/maps/place/39%C2%B044%2755.7%22N+105%C2%B009%2747.9%22W/@39.7481428,-105.1769281,4304m/data=!3m1!1e3!4m5!3m4!1s0x0:0x3e7625a8c4a8415f!8m2!3d39.7488!4d-105.1633&quot; rel=&quot;nofollow noreferrer&quot;&gt;39.7488 deg N, -105.1633 deg E&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The linked page has some photographs with this descriptive text:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Cretaceous-Paleogene (K-Pg) boundary, formerly known as the&#xA;Cretaceous-Tertiary (K-T) boundary, was first described in terrestrial&#xA;(non-marine) rocks at the above site on South Table Mountain in&#xA;Golden, Colorado back in 1943. This boundary actually isn't visually&#xA;well-defined here but was recognized on the basis of fossil evidence&#xA;long before the more recently applied evidence of the boundary was&#xA;imagined. It occurs somewhere within the eroded slope of the badlands&#xA;topography in the lower-right portion of the photograph. This site was&#xA;judged to be so important to the history of science that the National&#xA;Science Foundation held its 50th birthday party here in 2000. Note the&#xA;tall buildings of downtown Denver in the distance, about 9 mi (14 km)&#xA;directly to the east. Photo taken on January 30, 2011.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="18088" LastActivityDate="2022-05-28T10:33:07.697" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23862" PostTypeId="1" CreationDate="2022-05-28T14:22:00.400" Score="0" ViewCount="39" Body="&lt;p&gt;The isotopic fractionations in the precipitate are equilibrium fractionations and the evolution of a system can be described using Rayleigh destillation! The fractionation type during evaporation is mostly kinetic and the height of the isotope fractionation depends on the vapour pressure and the humidity of the air!  But this process can also be also described with the Rayleigh destilation if you assume that the humidity is 0%, right? However, if the humidity is 100%, there is probably an equilibrium between water and water vapour, but wouldn't this then be an equilibrium isotope effect? or isn't it, since the vapour pressure first has to be overcome.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2022-05-28T14:22:00.400" Title="Isotope fractionations" Tags="|climate|mapping|oxygen|isotopic|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23863" PostTypeId="2" ParentId="10357" CreationDate="2022-05-28T21:27:40.430" Score="1" Body="&lt;p&gt;While working in southern Minnesota for several months in the winter and spring of 2022, I noticed the river channel was frozen solid at La Crosse throughout January and February. When I first arrived in the area in early December ‘21, there was ice, but it was broken ice covering the river channel.  Being from the south, I was fascinated by this and would always observe the River as I crossed it going into La Crosse each week. There was a lot of ice fishing on the tributaries/marshes just off of the river in the area, and I’m pretty sure I spotted some ice fishing in the distance on the Mississippi itself just north of the dam and not too far from the river bank in La Crosse (La Crosse side of the river). All beautiful and fascinating.&lt;/p&gt;&#xA;" OwnerUserId="26930" LastActivityDate="2022-05-28T21:27:40.430" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23864" PostTypeId="1" CreationDate="2022-05-30T09:02:01.880" Score="4" ViewCount="719" Body="&lt;p&gt;If we are in Northern Hemisphere and there is a point where there is a high pressure, denote it by H, and there is a point where there is low pressure, denote it by L, (for simplicity assume them to lie latitudinally, that is H is on west and L on east).&lt;/p&gt;&#xA;&lt;p&gt;The pressure gradient force will drive the wind from H to L, and since we are in the Northern Hemisphere, the wind gets deflected to the right by the Coriolis force.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GINyN.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GINyN.png&quot; alt=&quot;Enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The wind began with a velocity &lt;span class=&quot;math-container&quot;&gt;$\vec{V}$&lt;/span&gt; initially directed towards L (that is in the direction of pressure gradient force &lt;strong&gt;P&lt;/strong&gt;), but due to Coriolis force &lt;strong&gt;C&lt;/strong&gt;, at right angles to the velocity, it turns rightwards and we get a &lt;a href=&quot;https://en.wikipedia.org/wiki/Geostrophic_wind&quot; rel=&quot;nofollow noreferrer&quot;&gt;geostrophic wind&lt;/a&gt;, that is a wind blowing parallel to isobars. But in all this, when did &lt;strong&gt;C&lt;/strong&gt; get cancelled with &lt;strong&gt;P&lt;/strong&gt;?&lt;/p&gt;&#xA;" OwnerUserId="26933" LastEditorUserId="502" LastEditDate="2022-06-01T12:05:24.980" LastActivityDate="2022-06-01T12:05:24.980" Title="On geostrophic wind. How can the Coriolis force cancel out the pressure gradient force when they are mutually perpendicular?" Tags="|meteorology|geophysics|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23865" PostTypeId="2" ParentId="23864" CreationDate="2022-05-30T09:09:50.707" Score="6" Body="&lt;p&gt;Consider the scenario just after the picture, the wind is blowing southwards, but it still have tendency to blow towards L because of Pressure gradient force, but now the Coriolis force will act rightwards, that is towards west and if &lt;strong&gt;|C| = |P|&lt;/strong&gt;, the two opposite forces will cancel each other out and the wind will continue to flow in parallel fashion to isobars. The situation after a few moments will be:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/bGALD.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bGALD.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\vec{V'}$&lt;/span&gt; is the velocity just after the situation shown in question diagram. Thus, that is how &lt;strong&gt;C&lt;/strong&gt; and &lt;strong&gt;P&lt;/strong&gt; will cancel each other out.&lt;/p&gt;&#xA;" OwnerUserId="26933" LastEditorUserId="6298" LastEditDate="2022-05-31T04:24:08.157" LastActivityDate="2022-05-31T04:24:08.157" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23866" PostTypeId="2" ParentId="23864" CreationDate="2022-05-30T12:09:14.780" Score="5" Body="&lt;p&gt;If a pressure gradient force poofed and appeared out of nothing, then it would be as you suggest:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The wind would start out moving from high to low.&lt;/li&gt;&#xA;&lt;li&gt;The wind would continue to accelerate due to PGF, and the wind would shift direction (to the right in the NH) due to Coriolis.&lt;/li&gt;&#xA;&lt;li&gt;At each point during the turn, more of the Coriolis turn (to the&#xA;right in the NH) would be becoming in opposition to the PGF rather&#xA;than perpendicular to it... so gradually the speed acceleration&#xA;decreases (more of the forces are perpendicular to motion rather than&#xA;in line with the motion)... and the directional acceleration (after&#xA;initially increasing due to increasing velocity &lt;span class=&quot;math-container&quot;&gt;$\implies$&lt;/span&gt; increasing&#xA;Coriolis) also gradually decreases (as the wind turns [more south in&#xA;your picture], the PGF starts to counteract more of the coriolis).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;In reality, at frictionless levels like 500 mb, because pressure development is generally gradual, the wind steadily adjusts as the changes gradually occur, and so the result is that winds are basically geostrophic always.  I'm pretty sure it's still not absolutely truly perfectly 100% geostrophic, or a moving parcel of air at that level would never change direction, but the component of ageostrophic wind is so small as to basically allow it to be idealized as perfectly geostrophic.&lt;/p&gt;&#xA;&lt;p&gt;I think your struggle is that you draw &lt;span class=&quot;math-container&quot;&gt;$\overrightarrow{v}$&lt;/span&gt; showing it changing (having it curved), whereas you draw the forces as instantaneous snapshots.  Instead, try to consider each instant as the &lt;span class=&quot;math-container&quot;&gt;$\overrightarrow{v}$&lt;/span&gt; vector turns... your &lt;span class=&quot;math-container&quot;&gt;$\overrightarrow{c}$&lt;/span&gt; vector is also changing direction to match.&lt;/p&gt;&#xA;&lt;p&gt;So initially &lt;span class=&quot;math-container&quot;&gt;$\overrightarrow{c}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\overrightarrow{P}$&lt;/span&gt; don't cancel at all, but as the wind turns, more and more of them cancels until it reaches a steady state when &lt;span class=&quot;math-container&quot;&gt;$\overrightarrow{c}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\overrightarrow{P}$&lt;/span&gt; are completely equal and opposite and so the velocity vector is unchanging (in magnitude and direction) as well.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-05-31T04:24:48.727" LastActivityDate="2022-05-31T04:24:48.727" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23867" PostTypeId="2" ParentId="23856" CreationDate="2022-05-30T13:01:16.713" Score="2" Body="&lt;p&gt;My answer focuses on a &amp;quot;simple and easy to understand and roughly accurate model for understanding greenhouse gases&amp;quot;. This is the same model used in a comment to your question.&lt;/p&gt;&#xA;&lt;p&gt;The most basic model for understanding the greenhouse effect is based on radiative equilibrium. Incoming solar radiation is balanced by outgoing (long wave) radiation. Stated in terms of energy: On large timescales outgoing energy must equal incoming energy.&lt;/p&gt;&#xA;&lt;p&gt;A unit square facing the sun at the top of the atmosphere receives &lt;span class=&quot;math-container&quot;&gt;$S_0 \approx 1360$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\text{W}\text{m}^{-2}$&lt;/span&gt;, with &lt;span class=&quot;math-container&quot;&gt;$S_0$&lt;/span&gt; being the &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_constant&quot; rel=&quot;nofollow noreferrer&quot;&gt;solar constant&lt;/a&gt;. The area hit by solar radiation is a disc with earths radius &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt;. Thus, the energy/time earth receives is &lt;span class=&quot;math-container&quot;&gt;$E_I = S_0\pi r^2$&lt;/span&gt;. A fraction of the radiation is reflected (see &lt;a href=&quot;https://en.wikipedia.org/wiki/Albedo&quot; rel=&quot;nofollow noreferrer&quot;&gt;albedo&lt;/a&gt;), yielding &lt;span class=&quot;math-container&quot;&gt;$E_I = S_0(1-\alpha)\pi r^2$&lt;/span&gt;, with &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt; being the albedo. Earths albedo is around &lt;span class=&quot;math-container&quot;&gt;$\alpha = 0.3$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;If we think about earth being a &lt;a href=&quot;https://en.wikipedia.org/wiki/Black_body&quot; rel=&quot;nofollow noreferrer&quot;&gt;black body&lt;/a&gt; with no atmosphere we can use the &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stefan-Boltzmann law&lt;/a&gt; to estimate the outgoing radiative energy to be &lt;span class=&quot;math-container&quot;&gt;$E_O = \sigma T_s^4 4 \pi r^2$&lt;/span&gt;, with &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_constant&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stefan-Boltzmann constant&lt;/a&gt; &lt;span class=&quot;math-container&quot;&gt;$\sigma = 5.67 \times10^{-8}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\text{W}\text{m}^{-2}\text{K}^{-4}$&lt;/span&gt; and earths surface Temperature &lt;span class=&quot;math-container&quot;&gt;$T_s$&lt;/span&gt;. The factor 4 occurs because for the outgoing radiation we need to consider earths whole surface (&lt;a href=&quot;https://earthscience.stackexchange.com/questions/20937/why-divide-total-insolation-by-4/20944#20944&quot;&gt;I gave an explanation on why this is a reasonable assumption here&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;Since energy needs to be balanced we can equate &lt;span class=&quot;math-container&quot;&gt;$E_I = E_O$&lt;/span&gt; and solve for &lt;span class=&quot;math-container&quot;&gt;$T_s$&lt;/span&gt; which will yield us insight on how severe the greenhouse effect actually is.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA; T_s = \left(\frac{S_0(1-\alpha)}{4\sigma} \right)^{\frac{1}{4}} \approx 255 \, \text{K} \approx -18°\text{C}&#xA;\end{equation}&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;We observe that our estimated temperature is a lot colder than earths average Temperature, which is around &lt;span class=&quot;math-container&quot;&gt;$15°\text{C}$&lt;/span&gt; or &lt;span class=&quot;math-container&quot;&gt;$288.15 \, \text{K}$&lt;/span&gt;. This corresponds to a greenhouse effect of approximately &lt;span class=&quot;math-container&quot;&gt;$\sigma(288^4 \text{K}^4 - 255^4 \text{K}^4) \approx 150 \, \text{Wm}^{-2}$&lt;/span&gt;. This is the amount of energy/time/unit square earth receives because of the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;We could refine the model by adding atmospheric layers to the problem, however I think this captures the essence.&lt;/p&gt;&#xA;" OwnerUserId="18833" LastEditorUserId="2470" LastEditDate="2022-05-30T16:28:41.880" LastActivityDate="2022-05-30T16:28:41.880" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23870" PostTypeId="2" ParentId="23666" CreationDate="2022-05-31T15:15:56.547" Score="1" Body="&lt;p&gt;Not to worry, the gas burned in the kiln to produce the cement produces an offsetting amount of water.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2022-05-31T15:15:56.547" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23871" PostTypeId="1" CreationDate="2022-06-01T11:24:20.500" Score="1" ViewCount="495" Body="&lt;p&gt;and thank you for answering&#xA;I am trying to plot a &lt;a href=&quot;https://media.geeksforgeeks.org/wp-content/uploads/20200413150909/plot31.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;quiver plot&lt;/a&gt; on a basemap (The basemap has to be a good quality map such as openstreetmap) and I can't find a way to do it.&lt;/p&gt;&#xA;&lt;p&gt;There are some examples on the web of doing it with a package called mpl_toolkits which is now deprecated. Another option might be using geopandas and contextily. I was able to create a point plot but could not find a way to plot 3d plots (contour/contourf/pcolor).&lt;/p&gt;&#xA;&lt;p&gt;Has anyone done it before?&#xA;Thanks again&#xA;Yair&lt;/p&gt;&#xA;" OwnerUserId="20249" LastActivityDate="2022-06-01T11:24:20.500" Title="How to plot quiver (current/wind arrows) plot on a basemap" Tags="|models|mapping|python|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="23872" PostTypeId="1" CreationDate="2022-06-01T12:11:44.357" Score="2" ViewCount="31" Body="&lt;p&gt;I want to plot atmospheric data (&lt;sup&gt;2&lt;/sup&gt;H and &lt;sup&gt;18&lt;/sup&gt;O) on a map and use ordinary kriging for the interpolation. Now I have the question how to quantify which variogram method (Gaussian, exponential spherical) I should use. Is there a mathematical approach to quantify each method or should I just plot my data in the variogram and see which method covers the most points?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="2470" LastEditDate="2022-06-01T23:18:31.787" LastActivityDate="2022-06-01T23:18:31.787" Title="Which variogram method for ordinary kriging?" Tags="|climate-change|mapping|isotopic|interpolation|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23873" PostTypeId="1" AcceptedAnswerId="23877" CreationDate="2022-06-02T11:00:54.990" Score="3" ViewCount="92" Body="&lt;p&gt;Hi I want to create two isotope data (1970-1980) and (2010-2020). As you can mention, the interpolation for the two maps is based on the average value measured at different stations in each time period.&lt;/p&gt;&#xA;&lt;p&gt;However, I now have the problem that I do not have the data from the particular years for all stations.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LisXS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LisXS.png&quot; alt=&quot;![enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;For example, station B has data from 1970-1974 and 1979-1980.&#xA;So the data from 1975-1978 are missing!&lt;/p&gt;&#xA;&lt;p&gt;But if I now calculate the average at this station and interpolate it with the data that includes a data set (A) for all 10 years, I will distort my model!&#xA;Is there a simple mathematical solution for weighting the data?&lt;/p&gt;&#xA;&lt;p&gt;Is it a solution to multiply the B Average Value with 0.7, so the weighted average value will be 3.5?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-06-03T08:04:27.697" LastActivityDate="2022-06-06T15:42:49.903" Title="Problems when interpolating time series data (average problem)" Tags="|climate-models|python|time|database|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23874" PostTypeId="1" CreationDate="2022-06-02T14:26:37.077" Score="3" ViewCount="114" Body="&lt;p&gt;I see the term Tropical Forcing used in weather synopses but have been unable to find a concise definition of the term. Also, is &amp;quot;Tropical Forcing&amp;quot; a different concept than &amp;quot;Climate Forcing&amp;quot;?&lt;/p&gt;&#xA;" OwnerUserId="26946" LastActivityDate="2022-06-02T15:14:58.737" Title="What is a Tropical Forcing and is it related to Climate Forcing?" Tags="|meteorology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23875" PostTypeId="2" ParentId="23874" CreationDate="2022-06-02T15:14:58.737" Score="3" Body="&lt;p&gt;It depends on the context. But I have added my intuitive explanation below. My general instinct is that whenever something is labeled as a forcing, the person writing it is as a black box. So &amp;quot;tropical forcing&amp;quot; likely means the area of interest is extratropical. When someone writes &amp;quot;climate forcing&amp;quot; the subject is something that is not climate (such as biology).&lt;/p&gt;&#xA;&lt;p&gt;The tropics have dynamics and features that are different from the other parts of the climate (midlatitudes, upper latitudes). In the tropics, a good amount of the circulation is driven by condensation. In the tropics, the amount of sunlight that is received does not vary as much as in the midlatitudes. The tropics can generate features, such as tropical cyclones, the Intertropical convergence zone, or El Nino/La Nina that heavily influences the midlatitudes.&lt;/p&gt;&#xA;&lt;p&gt;Climate forcing, on the other hand, is a general term that describes the mechanics of the atmosphere at large. These include heat transport by ocean gyres, aerosols, and greenhouse gas forcing. Now one can make the argument that this distinction between tropics and extratropics is semantic, which is fair. But it follows in the methodological reductionism of science to break the climate system by geography.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2022-06-02T15:14:58.737" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23876" PostTypeId="1" CreationDate="2022-06-02T23:10:08.080" Score="1" ViewCount="27" Body="&lt;p&gt;I am currently working at the Tren Maya project in México as part of the planing department; anyways I studied a Masters degree, and looking at the executive project, there are some parameters I’ve looked around a lot in the literature and I find myself unable to find the why of them, and I’m just curious about.&lt;/p&gt;&#xA;&lt;p&gt;My question is simple, in the design of the railway embankment, lets say we have a 7 meters height embankment over a natural soil that meets the loading capacity, so it is divided in layers of 0.3 meters such that the bottom n layers must meet a 90% compaction degree, and the last 5 upper layers must meet a ≥ 97% compaction degree. Searching I found out in &amp;quot;Geotechnical Parameters of Soil, Considering the Effect of Additional Compaction of Embankment&amp;quot; that the reason why is that upper layer compaction actions indirectly compact lower ones, and this effect must be considered in the design.&lt;/p&gt;&#xA;&lt;p&gt;Yet, generally this compaction degree seem to default to be greater than 90% for lower layers and greater than 97% or 100% for upper layers. A prove of this:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UiGNR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UiGNR.png&quot; alt=&quot;Capture from Technical memorandum of the California H-S Train Project&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Why 90%? Why not 91% of compaction degree? Or 92%? or 100%? I know compacting all layers 100% degrees would be pretty high in costs, but then why 90%?&lt;/p&gt;&#xA;" OwnerUserId="26947" LastActivityDate="2022-06-02T23:10:08.080" Title="How is layer compaction degree designed to be ≥90% in lower layers and ≥ 95% in the upper 5 ft in a railway embankment?" Tags="|soil|research|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23877" PostTypeId="2" ParentId="23873" CreationDate="2022-06-03T11:29:12.710" Score="5" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Is it a solution to multiply the B Average Value with 0.7, so the weighted average value will be 3.5?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;No, this is not a solution. Doing this effectively assigns a value of zero to the stations that do not have data, which is the wrong thing to do.&lt;/p&gt;&#xA;&lt;p&gt;If you want to fill in the missing data you have to apply data interpolation techniques. Such techniques are only valid if there is correlation between the sampling points.&lt;/p&gt;&#xA;&lt;p&gt;To fill in those missing gaps you will have to do additional calculations. Which technique you use depends on the result you want or what is &lt;strong&gt;now&lt;/strong&gt; considered state of the art for the field the data is applicable to.&lt;/p&gt;&#xA;&lt;p&gt;Until the mid 1990s to early 2000s, when estimating values of grade for ore reserves, using block modelling methods, &lt;a href=&quot;https://en.wikipedia.org/wiki/Inverse_distance_weighting&quot; rel=&quot;noreferrer&quot;&gt;inverse distance weighting&lt;/a&gt; methods were used. Initially, &lt;span class=&quot;math-container&quot;&gt;$\frac{1}{d}$&lt;/span&gt; was used as this was a relatively quick calculation to perform. It was later discovered that &lt;a href=&quot;https://en.wikipedia.org/wiki/Inverse_distance_weighting&quot; rel=&quot;noreferrer&quot;&gt;inverse distance squared&lt;/a&gt; &lt;span class=&quot;math-container&quot;&gt;$(\frac{1}{d^2})$&lt;/span&gt; gave better results. In some instances, inverse distance to the power &lt;span class=&quot;math-container&quot;&gt;$n$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$(\frac{1}{d^n})$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$n$&lt;/span&gt; generally ranged between 2 and 2.5 was also used. Generally, however, inverse distance squared became industry &amp;quot;standard&amp;quot; for a period of time.&lt;/p&gt;&#xA;&lt;p&gt;The benefit of inverse distance squared weighting compared to simple inverse distance weighting was it gave less weighting to more distance samples. This is based on the logic that samples that are close to one another are more likely to have been deposited under more similar conditions and thus would more likely be related to one another.&lt;/p&gt;&#xA;&lt;p&gt;Since the early 2000s inverse distance weighting methods have been replaced by &lt;a href=&quot;https://en.wikipedia.org/wiki/Kriging&quot; rel=&quot;noreferrer&quot;&gt;kriging&lt;/a&gt;. One of the main differences between kriging and all forms of inverse distance weighting is with kriging, the sum of the weights equals 1. With the other methods, there is no limit, or specification to what the sum of the weight should be.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-06-03T11:29:12.710" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23878" PostTypeId="2" ParentId="23821" CreationDate="2022-06-04T03:51:37.327" Score="2" Body="&lt;p&gt;Evaporation requires energy (~680 kWh / m³ water) and as always this is mainly supplied by the sun. At Lake Mead I estimate ~ 2000 kWh/m² per year of incoming solar radiation.&lt;/p&gt;&#xA;&lt;p&gt;A highly reflective bubble wrap (e.g. rescue foil on the top) would be a major improvement. Black shadow balls should therefore actually be white in order to keep the water optimally cool. Funny that the inventor's name is Brian White and that albedo and climate science are foreign words to him. (The idea came from now-retired LADWP biologist Brian White).&lt;/p&gt;&#xA;&lt;p&gt;But what happens to the bubble wrap in strong winds, waves or hail? Or when a drunken sailor with a motorboat loses his bearings in a dark and foggy night?&lt;/p&gt;&#xA;&lt;p&gt;There is so much plastic floating in the seas, rivers and lakes that I have an aversion to both solutions for that reason alone. The better solution is therefore imho floating PV-(T), which are easy to install and maintain in smaller plots.&lt;/p&gt;&#xA;&lt;p&gt;And because solar cells become less efficient as they heat up, the water's cooling effect can increase their conversion ability by as much as 20 percent - &lt;a href=&quot;https://www.scientificamerican.com/article/putting-solar-panels-on-water-is-a-great-idea-mdash-but-will-it-float/&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Putting Solar Panels on Water Is a Great Idea—but Will It Float?&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;If you look at such a floating construction (see photos in the link) energetically, each m² of photovoltaic module cools the lake by ~2000KWh and, with an optimized construction, can also offer relatively good wind and evaporation protection for the water surface under the raft.&lt;/p&gt;&#xA;&lt;p&gt;The annual electricity production of ~ 500 kWh/m² means up to 0.5 TWh/y on a 1 km² PV systems and an estimated 1.5 million m³ of water that does not evaporate and can additionally rush through the turbines of the Hover Dam.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Since there are certainly hours when the power station has to hold current peaks on a sunny day, although not so much water would be needed downstream. Those are the times when solar power turns into water saving and 1 km² PV modules with max. ~ 250 MW output can replace a turbine with 100 m³/sec throughput at midday. 100 such hours/y gigantic 36 million m³ can possibly be retained in the lake. 10% of Lake Mead (64km²) covered can thus reduce at least 100-150 million m³ of evaporation &amp;amp; discharge.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;While that's only a ~20 cm gain/yr in water level of Lake Mead, if other lakes like Lake Powell upstream and downstream in the Colorado River catchment practice the same policy, this can save many of the water bodies threatened by drying up from catastrophe.This could and must be combined with other policies such as:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Save water consumption!&lt;/li&gt;&#xA;&lt;li&gt;Replace drinking water with rainwater from the roof&lt;/li&gt;&#xA;&lt;li&gt;in winter, the lake can be cooled with heat pumps and district heating can supply many adjacent consumers with CO&lt;sub&gt;2&lt;/sub&gt;-free heat&lt;/li&gt;&#xA;&lt;li&gt;in summer the lake stays cooler and then supplies the same consumers with cold.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Actually, evaporation is IMHO for the world climate an important, beneficial process for cooling the earth's surface and for cloud formation. We should therefore definitely invest part of the water saving in vegetation and wildlife, which is also under great pressure due to the drought, and also always represents a CO&lt;sub&gt;2&lt;/sub&gt; store.&lt;/p&gt;&#xA;&lt;p&gt;How to set up effective protection against drought AND flooding through intelligent water management can be read here:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://climate-protecion-hardware.webnode.page/english/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://climate-protecion-hardware.webnode.page/english/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Thinking globally water retention and an intensification of evaporation and thus cloud formation even has the potential to lower sea level rise and earth temperature. !!!&lt;/p&gt;&#xA;" OwnerUserId="26198" LastEditorUserId="26198" LastEditDate="2022-06-04T16:08:12.820" LastActivityDate="2022-06-04T16:08:12.820" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23879" PostTypeId="1" CreationDate="2022-06-04T10:19:37.813" Score="0" ViewCount="86" Body="&lt;p&gt;I have managed to plot various points on a map and interpolate with ordinary kriging. However, my data does not look anything like it should. Do I need to use an algorithm to fill in the missing data? Does anyone know how the RCWIP2 model does this?&lt;/p&gt;&#xA;&lt;p&gt;My data looks like this:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/matEB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/matEB.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;and it should look like this:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.researchgate.net/figure/Global-mean-annual-average-leaf-water-d-18-O-and-d-2-H-isoscapes-for-the-sites-of_fig1_226462314&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/figure/Global-mean-annual-average-leaf-water-d-18-O-and-d-2-H-isoscapes-for-the-sites-of_fig1_226462314&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Does anyone have an idea where to get an algorithm (open source) for this? Or is it possible to create a better interpolation using the GNIP data (without an algorithm)?&lt;/p&gt;&#xA;&lt;p&gt;I have adjusted the colour scale (it doesn't make sense to use a larger colour range) and displayed the measuring points. But you can see that the interpolation is much too coarse. What can I do?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/os5OI.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/os5OI.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The values central europe, for example, look like this:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;0,0,100400,78.91666667,11.93333333,-11.948727272727274&#xA;1,1,284500,66.4968611111111,25.7551805555556,-15.65725&#xA;2,2,291701,62.8917944444444,27.6254222222222,-14.696333333333333&#xA;3,3,297401,60.1800888888889,24.8328611111111,-12.793636363636363&#xA;4,4,304401,58.15,-4.975,-5.424&#xA;5,5,365302,51.6,-1.1,-8.102181818181817&#xA;6,6,395300,51.93,-10.25,-6.069957643495706&#xA;7,7,403000,64.13,-21.93,-9.823909326232151&#xA;8,8,432000,76.7666666666667,-18.6666666666667,-22.848&#xA;9,9,628001,53.23,6.55,-8.19874809968471&#xA;10,10,660100,47.5426086672,7.58371692988,-11.620857142857144&#xA;11,11,661700,46.9814140076,6.60799965476,-9.690999999999999&#xA;12,12,663100,46.9522256303,7.4393205714,-12.386181818181818&#xA;13,13,663300,47.3723359688,8.08313824523,-11.575&#xA;14,14,663700,46.7273863351,8.18678216294,-11.338727272727272&#xA;15,15,668100,47.4269289828,9.4007768793,-10.921999999999999&#xA;16,16,670500,46.3986411863,6.23380378665,-9.955272727272726&#xA;17,17,672000,46.2203086749,7.33848445042,-12.540444444444445&#xA;18,18,673401,46.657725176,8.29270683241,-12.813636363636364&#xA;19,19,674400,46.5724847069,8.33271962058,-12.234545454545453&#xA;20,20,676000,46.1737858341,8.78855605127,-9.962909090909092&#xA;21,21,679201,46.4914336729,9.89818088768,-13.835999999999999&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;You can see that the data is very variable and that should have an effect on the interpolation, right?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="81" LastEditDate="2022-06-07T21:47:02.993" LastActivityDate="2022-06-07T21:47:02.993" Title="Algorithm for the interpolation?" Tags="|climate-models|mapping|python|isotopic|interpolation|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="23880" PostTypeId="2" ParentId="23837" CreationDate="2022-06-04T23:43:14.360" Score="2" Body="&lt;p&gt;You may want to explore &lt;a href=&quot;https://space.stackexchange.com/questions/18374/what-forms-of-water-ice-have-been-observed-and-verified-in-the-solar-system#33570&quot;&gt;this question from Space Exploration SE&lt;/a&gt;. Strictly speaking, the question refers to ice detection, but the methods described there can also be used to identify liquid water.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Seismic measurements.&lt;/strong&gt; These may be used to identify different phases of ice as well as liquid water, because different phases of the same chemical makeup will lead to different propagation of the seismic waves. Ref. &lt;a href=&quot;https://doi.org/10.1002/2017JE005338&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt; describes how the technique may be applied to outer-planet moons to reveal the water/ice structure.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Inclusions.&lt;/strong&gt; The same answer also describes the direct finding of high-pressure ice (Ice VII) in diamonds on Earth &lt;a href=&quot;https://www.science.org/doi/10.1126/science.aao3030&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;. The high-pressure ice does not reveal bodies of water as such, but it gives evidence of molecular &lt;span class=&quot;math-container&quot;&gt;$\ce{H2O}$&lt;/span&gt; originating from the deep mantle.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;S.C Stähler, M. P. Planning, S. D. Vance, R. D. Lorentz, N. van Driel, T. Nissen-Meyer, S. Kedar (2018). &amp;quot;Seismic propagation in icy ocean worlds&amp;quot;. &lt;em&gt;Journal of Geophysical Research: Planets&lt;/em&gt;, 123. https:// doi.org/10.1002/2017JE005338.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;O. Tscauner, S. Huang, E. V. B. Prakapenka, C. Ma, G. R. Rossman, A. H. Shen, D. Zhang, M. Newville, A. Lanzirotti, K. Tait (2018). &amp;quot;Ice-VII inclusions in diamonds: Evidence for aqueous fluid in Earth’s deep mantle&amp;quot;.&#xA;&lt;em&gt;Science&lt;/em&gt;  &lt;strong&gt;359&lt;/strong&gt; (6380), 1136-1139. &lt;a href=&quot;https://www.science.org/doi/10.1126/science.aao3030&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.science.org/doi/10.1126/science.aao3030&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2022-06-14T01:52:57.147" LastActivityDate="2022-06-14T01:52:57.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23881" PostTypeId="2" ParentId="23362" CreationDate="2022-06-05T01:52:39.630" Score="1" Body="&lt;p&gt;In the mixed layer the &lt;strong&gt;virtual&lt;/strong&gt; potential temperature &lt;span class=&quot;math-container&quot;&gt;$\theta_v$&lt;/span&gt; is constant and therefore, you substitute the virtual temperature &lt;span class=&quot;math-container&quot;&gt;$T_v$&lt;/span&gt; for &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\theta_v = T_v \left( \frac{p_0}{p} \right)^{\frac{R}{c_p}} = T \left( \frac{p_0}{p} \right)^{\frac{R}{c_p}} (1+0.61r) = \theta (1+0.61r)&#xA;\end{equation}&lt;/span&gt;&#xA;Here&#xA;&lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; is the mixing ratio (mass of water/mass of dry air). In the mixed layer &lt;span class=&quot;math-container&quot;&gt;$\partial r/\partial z = 0$&lt;/span&gt; or &lt;span class=&quot;math-container&quot;&gt;$r=\text{const}$&lt;/span&gt;. and thus, your virtual temperature increases in the presence of moisture. Your profile will thus, stay parallel to the dry adiabatic lines.&lt;/p&gt;&#xA;&lt;p&gt;Your lapse rate will only change if air is saturated &lt;strong&gt;and&lt;/strong&gt; water vapor condenses, due to the latent energy release.&lt;/p&gt;&#xA;" OwnerUserId="18833" LastEditorUserId="18833" LastEditDate="2022-06-05T02:16:40.403" LastActivityDate="2022-06-05T02:16:40.403" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23885" PostTypeId="2" ParentId="23873" CreationDate="2022-06-06T15:42:49.903" Score="0" Body="&lt;p&gt;With year long data-gaps, any type of interpolation which does not account for environmental forcing (i.e. models) would be an inadequate comparison.&#xA;For example, extreme years that are included in A but not in B would affect your comparison greatly. I would rather mask the A dataset to match the years available in B or fill the missing years using a process based model with environmental forcing data outputting the isotope data you need.&lt;/p&gt;&#xA;" OwnerUserId="26962" LastActivityDate="2022-06-06T15:42:49.903" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23888" PostTypeId="1" CreationDate="2022-06-07T01:18:21.693" Score="2" ViewCount="52" Body="&lt;p&gt;I saw a similar previous question on this website about the temperature of the Earth with no atmosphere.  It sounds like if the Earth did lose its atmosphere we’d end up with either Snowball Earth or slushy Snowball Earth.&lt;/p&gt;&#xA;&lt;p&gt;In that thread someone said the new average temperature of the Earth would be around 274.5K.&lt;/p&gt;&#xA;&lt;p&gt;What I’d like to know is, if Earth lost it’s atmosphere, what would the new minimum and maximum temperatures be?&lt;/p&gt;&#xA;&lt;p&gt;According to NASA currently the Earth has min of -88C and a max of 58C.&lt;/p&gt;&#xA;&lt;p&gt;I am wondering if the Earth’s new min max would be similar to the moon: -233C min and 122C max.&lt;/p&gt;&#xA;" OwnerUserId="26969" LastActivityDate="2022-06-07T01:18:21.693" Title="What would the approx. min and max temperatures be for Snowball Earth with no atmosphere?" Tags="|atmosphere|temperature|moon|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23890" PostTypeId="1" CreationDate="2022-06-08T14:30:16.490" Score="6" ViewCount="768" Body="&lt;p&gt;I wanted to explain to high school students why the jet stream meanders, I am aware of the equations describing relative vorticity and planetary vorticity, the concept of conservation of vorticity i.e. F+ζ = constant.&lt;/p&gt;&#xA;&lt;p&gt;But I want to explain it without these equations in simple terms. Can anyone give a generic explanation in layman's terms.  It's ok if it's not 100% accurate but just gives a basic understanding of the concept.&lt;/p&gt;&#xA;" OwnerUserId="26979" LastEditorUserId="6298" LastEditDate="2022-06-09T17:10:42.240" LastActivityDate="2022-09-22T10:25:39.740" Title="Why does the jet stream meander?" Tags="|meteorology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23891" PostTypeId="1" CreationDate="2022-06-08T19:31:50.737" Score="4" ViewCount="73" Body="&lt;p&gt;The SETI Institute recently &lt;a href=&quot;https://twitter.com/SETIInstitute/status/1529832994395004936&quot; rel=&quot;nofollow noreferrer&quot;&gt;tweeted&lt;/a&gt; the image below, with the text:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;#PPOD: Here is another cool rock at Gale crater on Mars! &lt;strong&gt;The spikes are most likely the cemented fillings of ancient fractures in a sedimentary rock. The rest of the rock was made of softer material and was eroded away.&lt;/strong&gt; @NASA @NASAJPL @Caltech #MSSS fredk, acquired on May 17.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I don't know the size of these features; &lt;a href=&quot;https://en.wikipedia.org/wiki/Curiosity_(rover)#Mast_Camera_(MastCam)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Curiosity's Mastcam&lt;/a&gt; sits &lt;a href=&quot;https://en.wikipedia.org/wiki/Curiosity_(rover)#/media/File:PIA15279_3rovers-stand_D2011_1215_D521.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;about 2.2 meters above the surface&lt;/a&gt; but the right and left cameras have different magnifications. Another version of the image can be found &lt;a href=&quot;https://mars.nasa.gov/raw_images/1068632/?site=msl&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. Since &amp;quot;More Like This&amp;quot; links to &amp;quot;Instrument: MAST_RIGHT&amp;quot; we can guess it's the right camera&lt;/p&gt;&#xA;&lt;p&gt;Erosion on Mars has a very different history than it does on Earth. But I'm wondering, are there any remotely similar spike-like &amp;quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Cementation_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;cemented&lt;/a&gt; fillings of ancient fractures in a sedimentary rock&amp;quot; occurring on Earth? If so, what do they look like and how big are they?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;note:&lt;/strong&gt; A &lt;a href=&quot;https://en.wikipedia.org/wiki/Fulgurite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fulgurite&lt;/a&gt; explanation has been deemed not likely since these days the atmosphere can not support lightning powerful enough to create them.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/azDtS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/azDtS.jpg&quot; alt=&quot;spike-like &amp;quot;cemented fillings of ancient fractures in a sedimentary rock&amp;quot; on Mars from Curiosity rover's MastCam https://twitter.com/SETIInstitute/status/1529832994395004936&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6467" LastEditDate="2022-06-09T17:55:53.987" LastActivityDate="2022-06-09T17:55:53.987" Title="Do any spike-like &quot;cemented fillings of ancient fractures in a sedimentary rock&quot;, remotely similar to this one on Mars, occur on Earth?" Tags="|geology|structural-geology|erosion|mars|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23892" PostTypeId="2" ParentId="19780" CreationDate="2022-06-08T23:11:15.867" Score="0" Body="&lt;p&gt;That answer does not work for me.  Here in the California coastal range we have multiple springs which are located close to the top of ridges which couldn't possibly hold enough water to feed a large year round spring.&lt;/p&gt;&#xA;&lt;p&gt;Not far from me is Crazy Spring.  It's at about 4,000 feet and the top of the mountain ridge is only a few hundred feet higher.  Out of that spring comes a sizable stream of water, a creek, that runs all year.  All through the 5-6 month dry season where very little rainfall occurs.&lt;/p&gt;&#xA;" OwnerUserId="26980" LastActivityDate="2022-06-08T23:11:15.867" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23893" PostTypeId="2" ParentId="23891" CreationDate="2022-06-09T00:00:56.200" Score="2" Body="&lt;p&gt;Something that comes close are &lt;a href=&quot;https://en.wikipedia.org/wiki/The_Pinnacles_(Western_Australia)&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Pinnacles&lt;/a&gt;, near &lt;a href=&quot;https://en.wikipedia.org/wiki/Cervantes,_Western_Australia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cervantes&lt;/a&gt; in Western Australia. &lt;a href=&quot;https://duckduckgo.com/?t=ffab&amp;amp;q=the%20pinnacle%20western%20australia&amp;amp;iax=images&amp;amp;ia=images&amp;amp;pn=3&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Pinnacles&lt;/a&gt; are a field of rock pillars up to 3.5 m tall.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bUtNV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bUtNV.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;There are three theories for the formation of the Pinnacles:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The first theory states that they were formed as dissolutional remnants of the Tamala Limestone, i.e. that they formed as a result of a period of extensive solutional weathering (karstification). Focused solution initially formed small solutional depressions, mainly solution pipes, which were progressively enlarged over time, resulting in the pinnacle topography. Some pinnacles represent cemented void infills (microbialites and/or re-deposited sand), which are more resistant to erosion, but dissolution still played the final role in pinnacle development.&lt;/p&gt;&#xA;&lt;p&gt;A second theory states that they were formed through the preservation of tree casts buried in coastal aeolianites, where roots became groundwater conduits, resulting in the precipitation of indurated (hard) calcrete. Subsequent wind erosion of the aeolianite then exposed the calcrete pillars.&lt;/p&gt;&#xA;&lt;p&gt;A third proposal suggests that plants played an active role in the creation of the Pinnacles, based on the mechanism that formed smaller &amp;quot;root casts&amp;quot; in other parts of the world. As transpiration drew water through the soil to the roots, nutrients and other dissolved minerals flowed toward the root—a process termed &amp;quot;mass-flow&amp;quot; that can result in the accumulation of nutrients at the surface of the root, if the nutrients arrive in quantities greater than that needed for plant growth. In coastal aeolian sands that consist of large amounts of calcium (derived from marine shells), the movement of water to the roots would drive the flow of calcium to the root surface. This calcium accumulates at high concentrations around the roots and over time is converted into a calcrete. When the roots die, the space occupied by the root is subsequently also filled with a carbonate material derived from the calcium in the former tissue of the roots, and possibly also from water leaching through the structures. Although evidence has been provided for this mechanism in the formation of root casts in South Africa, evidence is still required for its role in the formation of the Pinnacles.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-06-09T00:00:56.200" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23894" PostTypeId="1" AcceptedAnswerId="25016" CreationDate="2022-06-09T10:35:08.050" Score="5" ViewCount="271" Body="&lt;p&gt;I have read about the Fixed Anvil Temperature (FAT) hypothesis and wonder why radiative cooling decreases with decreasing water vapor mixing ratio.&#xA;Doesn't this stand in contrast with the fact, that water vapor acts as a greenhous gas since it absorbs LW radiation? How can it then cool the atmosphere?&lt;/p&gt;&#xA;&lt;p&gt;Best regards&#xA;Jan&lt;/p&gt;&#xA;" OwnerUserId="26984" LastActivityDate="2023-03-11T15:56:04.337" Title="How does water vapor cool the troposphere?" Tags="|climate-change|climate|clouds|atmospheric-radiation|water-vapour|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23895" PostTypeId="1" CreationDate="2022-06-10T09:21:40.110" Score="2" ViewCount="45" Body="&lt;p&gt;Hi I am creating an isoscape model in which I am plotting &lt;sup&gt;2&lt;/sup&gt;H and &lt;sup&gt;18&lt;/sup&gt;O of precipitation. Until now I have always used ordinary kriging for the interpolation, but I am somewhat dissatisfied with the results. Since the data I use for interpolation comes from the precipitation, I assume that the expected value cannot be constant. However, this is assumed with ordinary kriging. Since universal kriging adds a trend to the data, this seems more sensible to me in this case. Therefore, I would like to ask which of these two kriging models is suitable for my interpolation and which trend would you recommend (in case of Universal Kriging) for the interpolation of precipitation data?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="2470" LastEditDate="2022-06-10T10:00:50.450" LastActivityDate="2022-06-10T10:00:50.450" Title="Universal or Ordinary Kriging?" Tags="|climate-change|climate-models|python|isotopic|interpolation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23896" PostTypeId="2" ParentId="23894" CreationDate="2022-06-10T14:18:35.443" Score="0" Body="&lt;p&gt;Evapotranspiration cools the surface of the Earth. Under the right circumstances, the moisture-laden air can rise higher into the troposphere, where it cools and eventually condenses into a mist in clouds. This helps cool the troposphere as condensation is an exothermic process. Cumulonimbus clouds can reach the very top of the troposphere. Greenhouse backradiation is greatly reduced at this high of an altitude, enabling the tops of those very tall clouds to radiate into space.&lt;/p&gt;&#xA;&lt;p&gt;This is of course countered by the fact that water vapor is a greenhouse gas. It is a very short-lived greenhouse gas. On average, water molecules stay in the atmosphere about 8 to 9 days between evapotranspiration and rain. The combination of the short-lived nature of water vapor, the interaction of the surface with clouds, and the different effects of high versus low clouds remain one of the key stumbling blocks in attaining a better understanding the sensitivity of the climate to rising &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; levels.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-06-10T14:18:35.443" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23900" PostTypeId="1" CreationDate="2022-06-11T14:31:18.143" Score="3" ViewCount="45" Body="&lt;p&gt;I am interested in whether short term (approximately decadal) variations in atmospheric CO&lt;sub&gt;2&lt;/sub&gt; would be observable in the consequent variability in Global Mean Surface Temperatures (GMSTs) as a result of the greenhouse effect.  Say we had a decadal cycle in atmospheric CO&lt;sub&gt;2&lt;/sub&gt;, how large would it have to be before that cycle were detectable?&lt;/p&gt;&#xA;&lt;p&gt;I suspect it would have to be very large because of the thermal inertia of the atmosphere/ocean system, but I don't have any intuition about the magnitude of the damping this would produce.&lt;/p&gt;&#xA;" OwnerUserId="624" LastEditorUserId="2470" LastEditDate="2022-06-13T12:24:05.853" LastActivityDate="2022-06-13T12:24:05.853" Title="How quickly can global means surface temperatures react to changes in CO2?" Tags="|climate-change|greenhouse-gases|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23901" PostTypeId="1" CreationDate="2022-06-11T14:52:29.857" Score="3" ViewCount="208" Body="&lt;p&gt;Why is one Joule of pasture is not equal to one Joule of meat according to &lt;a href=&quot;https://en.wikipedia.org/wiki/Emergy&quot; rel=&quot;nofollow noreferrer&quot;&gt;Emergy&lt;/a&gt; analysis? Is it because the energy going into the pasture can be renewable or non-rewnewable?&lt;/p&gt;&#xA;" OwnerUserId="26992" LastEditorUserId="18088" LastEditDate="2022-06-12T14:57:17.133" LastActivityDate="2022-06-12T14:57:17.133" Title="Why is one Joule of pasture is not equal to one Joule of meat according to Emergy analysis?" Tags="|energy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23902" PostTypeId="2" ParentId="23901" CreationDate="2022-06-11T19:59:05.683" Score="4" Body="&lt;p&gt;If a grazing animal eats pasture which contains 1 joule of energy it must use some of its own energy to eat and process the pasture.&lt;/p&gt;&#xA;&lt;p&gt;The act of moving around the field to eat uses energy the animal has stored. Similarly, the act of biting the pasture and chewing it uses animal energy. If the animal is a ruminant, such as cattle or goats, the pasture is regurgitated and chewed as cud a number of times. This utilizes animal energy. Moving the chewed pasture through the digestive tract and further processing it again uses animal energy. Finally, excreting the chewed pasture, now a bowel stool and soon to be manure, also uses animal energy. The animal expends energy in eating and processing the pasture.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, the act of excreting the pasture as manure means that not all the available energy within the consumed pasture was absorbed by the grazing animal. Some of it remains in the manure, available for other life forms: worms, insect larvae, bacteria to consume.&lt;/p&gt;&#xA;&lt;p&gt;So, the initial grazing animal didn't get all of the available energy within the pasture it ate. There is never 100 percent transference of energy. There are always energy losses. The initial grazing animal needs to consume more than 1 joule of pasture if it wants to absorb 1 joule of energy from what it eats.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-06-11T19:59:05.683" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23903" PostTypeId="2" ParentId="17827" CreationDate="2022-06-12T13:32:09.077" Score="2" Body="&lt;p&gt;Yes, it would be possible for a tropical cyclone to form over &amp;quot;land&amp;quot; in extreme circumstances. Tropical Storm Claudette of 2021 is a notable example of the phenomena known as the &amp;quot;brown ocean effect&amp;quot;. It formed over &amp;quot;land&amp;quot; areas of Southeastern Louisiana, which is a lot of marshy, swampy areas. The actual areas of land helped tighten the circulation enough for classification as a tropical storm (the disturbance was already producing gale force winds 12 hours or so prior to this point).  The disturbance was already nearly a tropical cyclone before reaching Southeast Louisiana, with deep convection. However, the low pressure system was broadly organized, which the brown ocean effect tightened it up just enough. It is an interesting scenario and stuff like that is tricky to forecast.&lt;/p&gt;&#xA;" OwnerUserId="26994" LastActivityDate="2022-06-12T13:32:09.077" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23904" PostTypeId="1" AcceptedAnswerId="23924" CreationDate="2022-06-12T13:32:09.967" Score="4" ViewCount="363" Body="&lt;p&gt;I am trying to select a region in the Mediterranean Sea from the ETOPO1 data.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;# bathymetry&#xA;from netCDF4 import Dataset&#xA;&#xA;data = Dataset(&amp;quot;ETOPO1_Bed_g_gdal.grd&amp;quot;,'r')&#xA;print(data.variables.keys())&#xA;&#xA;# Get data&#xA;lon_range = data.variables['x_range'][:]&#xA;lat_range = data.variables['y_range'][:]&#xA;topo_range = data.variables['z_range'][:]&#xA;spacing = data.variables['spacing'][:]&#xA;dimension = data.variables['dimension'][:]&#xA;z = data.variables['z'][:]&#xA;lon_num = dimension[0]&#xA;lat_num = dimension[1]&#xA;&#xA;# Prepare array&#xA;lon_input = np.zeros(lon_num); lat_input = np.zeros(lat_num)&#xA;for i in range(lon_num):&#xA;    lon_input[i] = lon_range[0] + i * spacing[0]&#xA;for i in range(lat_num):&#xA;    lat_input[i] = lat_range[0] + i * spacing[1]&#xA;&#xA;# Create 2D array&#xA;lon, lat = np.meshgrid(lon_input, lat_input)&#xA;&#xA;# Convert 2D array from 1D array for z value&#xA;topo = np.reshape(z, (lat_num, lon_num))&#xA;&#xA;# Select region&#xA;lon_idx_min = np.abs(lon_input-12.6).argmin()&#xA;lon_idx_max = np.abs(lon_input-13.4).argmin()&#xA;lat_idx_min = np.abs(lat_input-43.8).argmin()&#xA;lat_idx_max = np.abs(lat_input-44.2).argmin()&#xA;&#xA;# get data&#xA;topo[lon_idx_min:lon_idx_max, lat_idx_min:lat_idx_max].data&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;This returns an empty array:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;&amp;gt;&amp;gt;array([], shape=(0, 24), dtype=float64)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;One main questions:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;1 - What I am doing wrong?&lt;/strong&gt;&#xA;When I check the lon lat values I am slicing (lat_input[lat_idx_max] etc) they make sense. However, lon_idx_max and lon_idx_min are above len(topo) (11556 and 11604 vs 10801). I guess this is the problem, but I cannot find the cause of it.&lt;/p&gt;&#xA;&lt;p&gt;One bonus question:&lt;/p&gt;&#xA;&lt;p&gt;2 - Why if I flip lon and lat I get some data? Note that the data do not make sense (-4000ish meters in the Adriatic Sea...)&lt;/p&gt;&#xA;" OwnerUserId="6001" LastEditorUserId="6001" LastEditDate="2022-06-12T23:48:11.550" LastActivityDate="2022-06-15T09:38:59.203" Title="ETOPO1 region selection (in python)" Tags="|oceanography|python|topography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23906" PostTypeId="1" CreationDate="2022-06-13T00:00:56.750" Score="1" ViewCount="24" Body="&lt;p&gt;From my understanding the refractive index structure coefficient &lt;span class=&quot;math-container&quot;&gt;$C_{n}^2$&lt;/span&gt; measures atmospheric turbulence, but I'm not entirely sure as the literature seems to imply that there are slightly different meanings. I know that a small index of refraction can have an effect on a device's optical path length.&lt;/p&gt;&#xA;&lt;p&gt;Why is this term squared and how do we determine what coefficient n to use when describing electromagnetic waves propagating through the turbulent atmosphere?&lt;/p&gt;&#xA;&lt;p&gt;I have also seen in the literature that the optical path length difference equation &lt;span class=&quot;math-container&quot;&gt;$ OPD = |n_{1}l - n_{2}l|$&lt;/span&gt; replaced by &lt;span class=&quot;math-container&quot;&gt;$OPD = |n_{1}l - (n_{1} + \sqrt{C_{n}^2})l|$&lt;/span&gt; but I've never seen an explanation for this&lt;/p&gt;&#xA;" OwnerUserId="26999" LastEditorUserId="26999" LastEditDate="2022-06-13T00:07:06.797" LastActivityDate="2022-06-13T00:07:06.797" Title="What does the refractive index static coefficient measure and how is it derived?" Tags="|meteorology|atmosphere|atmosphere-modelling|electromagnetism|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23907" PostTypeId="1" CreationDate="2022-06-13T01:09:31.103" Score="3" ViewCount="212" Body="&lt;p&gt;With burning of fossil fuels resulting in increased CO&lt;sub&gt;2&lt;/sub&gt; concentration, I get how increase in CO&lt;sub&gt;2&lt;/sub&gt;  leads to a hotter planet and global warming because Earth's heat balance has been affected by CO&lt;sub&gt;2&lt;/sub&gt;  interfering with heat reflectivity.  But how does a hotter planet lead to lower localised extreme cold conditions at times - eg:  snow in UK and USA last winter&lt;/p&gt;&#xA;" OwnerUserId="24806" LastEditorUserId="2470" LastEditDate="2022-06-13T11:53:41.133" LastActivityDate="2022-06-15T03:25:26.947" Title="How does the increase in CO2 concentration model explain the extreme lower colder temperatures" Tags="|climate-change|climate|temperature|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23908" PostTypeId="1" CreationDate="2022-06-13T02:36:46.937" Score="4" ViewCount="75" Body="&lt;p&gt;In this equation, &lt;span class=&quot;math-container&quot;&gt;$n_{1} = n - 1 = \frac{77.6P}{T} \cdot 10^{-6}$&lt;/span&gt; the variable P is the total air pressure and T is expressed in Kelvin. This equation describes the refractive index of moist air as EM waves pass through.&lt;/p&gt;&#xA;&lt;p&gt;This formula appears in &lt;a href=&quot;https://books.google.ca/books/about/Imaging_Through_Turbulence.html?id=nuIC-Mk0R4UC&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;'Imaging through turbulence', Michael Roggemann and Byron Welsh, CRC Press 1996&quot;&gt;Roggemann &amp;amp; Welsh from 1996&lt;/a&gt;, but a similar version existed in &lt;a href=&quot;https://archive.org/details/jresv50n1p39/mode/2up&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;'The Constants in the Equation for Atmospheric Refractive Index at Radio Frequencies', Journal of Research of the Notional Bureau of Standards Vol. 50, No.1, January 1953 Research Paper 2385&quot;&gt;1953 (Smith, Weintraub)&lt;/a&gt;. The current literature uses this formula extensively but its never been properly explained.&lt;/p&gt;&#xA;" OwnerUserId="26999" LastEditorUserId="27775" LastEditDate="2022-10-17T01:40:09.850" LastActivityDate="2022-10-17T03:34:27.697" Title="Where does this refractive index formula come from: $n_{1} = n - 1 = \frac{77.6P}{T} 10^{-6}$" Tags="|meteorology|atmosphere|atmosphere-modelling|atmospheric-radiation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23909" PostTypeId="1" CreationDate="2022-06-13T09:46:06.330" Score="2" ViewCount="19" Body="&lt;p&gt;So what is the connection between climate change and phosphorus and what are some examples of potential feedback loops of this connection.&lt;/p&gt;&#xA;&lt;p&gt;I think a very common response is probably the leakage of some of the applied phosphorus (in fertilizer application) into rivers/ocean etc.&lt;/p&gt;&#xA;" OwnerUserId="26992" LastActivityDate="2022-06-13T09:46:06.330" Title="What is the connection between climate change and phosphorus and positive feedback loop?" Tags="|climate-change|environmental-protection|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23910" PostTypeId="2" ParentId="23907" CreationDate="2022-06-13T12:15:58.837" Score="4" Body="&lt;p&gt;The increase in carbon dioxide is altering climate, with an &lt;strong&gt;overall&lt;/strong&gt; increase in temperature. This does not mean that change will be uniform or consistently unidirectional.&lt;/p&gt;&#xA;&lt;p&gt;On a daily basis we experience weather, not climate and weather can be highly variable. It's with hindsight that we can state that the season just gone was average (typical) or extreme, or somewhere in between. Depending on location, one week can have blazing temperatures, followed by a week of near freezing temperatures.&lt;/p&gt;&#xA;&lt;p&gt;Factors that come into play are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;What's the situation with El Nino &amp;amp; La Nina in the Pacific Ocean?&lt;/li&gt;&#xA;&lt;li&gt;What's the situation with the Indian Ocean equivalent, the Indian&#xA;Ocean Dipole?&lt;/li&gt;&#xA;&lt;li&gt;What is happening with the jet streams? Are they meandering more than usual?&lt;/li&gt;&#xA;&lt;li&gt;How are localized high and low pressure systems bringing in cold air&#xA;from the Arctic or Antarctic regions, or warm from the equatorial&#xA;regions? Are there cold or warm fronts in the region and how do they combine with the localized pressure systems to affect weather&#xA;locally?&lt;/li&gt;&#xA;&lt;li&gt;Particularly for the northern hemisphere, the behavior of the polar vortex and how a weakening polar vortex can increase the meandering of the jet stream, allowing tongues of cold air to react part of the the UK and the US that normally would not be affected by such conditions. (Thanks to @David Hammen for reminding me of this).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;It's all part of the variability of weather: two steps forward, one step backwards, but the &lt;strong&gt;overall&lt;/strong&gt; trend is towards global warming.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2022-06-14T12:10:55.947" LastActivityDate="2022-06-14T12:10:55.947" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23911" PostTypeId="1" AcceptedAnswerId="23912" CreationDate="2022-06-13T14:51:11.630" Score="7" ViewCount="4276" Body="&lt;p&gt;According to the theory of continental drift, South America and Africa was so closed to each other that the convex triangle of South America meets the concave hollow of  Africa.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EHudT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EHudT.png&quot; alt=&quot;South America, Africa, Antarctica, India, and Australia shown conjoined, showing fossil evidence that they were conjoined&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;sub&gt;Source: &lt;a href=&quot;https://pubs.usgs.gov/gip/dynamic/continents.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;usgs.gov&lt;/a&gt;; this image is in the public domain&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, according to the Plate tectonics, there is much space (let's name it A) on the right-hand-side of South America and much space (let's name it B) on the left-hand-side of Africa.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5kwPR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5kwPR.jpg&quot; alt=&quot;Map of the major and some of the minor tectonic plates&quot; /&gt;&lt;/a&gt;&#xA;&lt;sub&gt;Source: &lt;a href=&quot;https://coast.noaa.gov/data/SEAMedia/Presentations/PDFs/Grade%205%20Unit%204%20Lesson%201%20Plate%20Tectonics.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;noaa.gov&lt;/a&gt;; this image is in the public domain&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;If these 2 plates were near to each other so that the two lands meet, where did the space A and B go? I think there are only 2 possibilities:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;A was over B,&lt;/li&gt;&#xA;&lt;li&gt;B was over A.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Both possibilities imply that South America and Africa can't join together to form a whole land. Do the two theories just contradict each other?&lt;/p&gt;&#xA;&lt;p&gt;(Source of the pictures:&lt;a href=&quot;https://education.nationalgeographic.org/resource/continental-drift&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://education.nationalgeographic.org/resource/continental-drift&lt;/a&gt;, &lt;a href=&quot;https://education.nationalgeographic.org/resource/plate-boundaries&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://education.nationalgeographic.org/resource/plate-boundaries&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="27003" LastEditorUserId="239" LastEditDate="2022-06-14T08:19:16.963" LastActivityDate="2022-06-16T10:58:43.720" Title="Does the Plate tectonics contradict the theory of continental drift?" Tags="|plate-tectonics|earth-history|" AnswerCount="4" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23912" PostTypeId="2" ParentId="23911" CreationDate="2022-06-13T16:04:09.257" Score="26" Body="&lt;p&gt;The boundary between the African and South American plate is a 'divergent' boundary. The two continents were joined as part of the Pangean super-continent. In the Cretaceous period a rift opened up and oceanic crust began forming along the &lt;a href=&quot;https://www.geolsoc.org.uk/Plate-Tectonics/Chap3-Plate-Margins/Divergent/Mid-Atlantic-Ridge&quot; rel=&quot;noreferrer&quot;&gt;mid-Atlantic ridge&lt;/a&gt;. The oceanic crust that fills the 'space' between the two continents has been created over the last 60 million years as magma rises and spreads, pushing the two continents apart.&lt;/p&gt;&#xA;&#xA;" OwnerUserId="21672" LastEditorUserId="-1" LastEditDate="2022-06-15T10:23:28.713" LastActivityDate="2022-06-15T10:23:28.713" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23913" PostTypeId="1" AcceptedAnswerId="23921" CreationDate="2022-06-13T16:47:23.690" Score="1" ViewCount="122" Body="&lt;p&gt;I have Macro question, and have enquired and discussed this topic with numerous people. My background is more in Economics and Finance, and read a very interesting article if I am not mistaken 10-15 years ago in the Farmers weekly of a WITS (Witwatersrand University Johannesburg) Geography professor who did a study in +-1905. Much of the article had to do with energy and the amount of energy used for cloud formation and movement from the Coast into the central parts of Southern Africa. Energy at the time I assume was a &amp;quot;buzz topic&amp;quot; as Electricity was in its early stage.&lt;/p&gt;&#xA;&lt;p&gt;The Professor had, among others, identified a location on the Zambezi River where the Zambezi and Chobe rivers meet +-40km upriver from the Victoria Falls, I assume close to the newly built Kazungula Bridge?&lt;/p&gt;&#xA;&lt;p&gt;In essence the suggestion was that by the construction a 14 meter high, controllable weir, in times of flooding the river would be able to flow along the ancient route, filling Lake Liambezi, and pushing back to Maun and back via the Boteti river ultimately filling the Makgadikgadi pans. This would also mitigate he flooding downstream in Mozambique.&lt;/p&gt;&#xA;&lt;p&gt;Building a 14m high Weir 1km wide using human and animal labour was an immense challenge 120 years ago. With modern earthmoving equipment such a task would be like building a &amp;quot;big farm dam&amp;quot; today!&lt;/p&gt;&#xA;&lt;p&gt;My question and thinking - this would refill the MASSIVE &amp;quot;evaporation pans&amp;quot; as they were centuries ago, which would in turn raise the rainfall in especially the winter months in much of the Northern Cape, and especially Botswana moving over to Limpopo province, and ultimately raise the Average Rainfall throughout the entire Southern Africa. The thinking is that Lake Malawi and some of the lakes further north have large cloud formations late afternoons?&lt;/p&gt;&#xA;&lt;p&gt;I assume in the 1900's many studies were done on energy rather than Water supply, with a considerably lower world populations at that time and sufficient water per capita.  Thus the building of the Cahora Basa dam and Lake Kariba for Hydro Electricity&lt;/p&gt;&#xA;&lt;p&gt;Today Climate change and its consequences are some of the biggest challenges facing Humanity, with water scarcity being the big factor in Sub-Sahara Africa.&lt;/p&gt;&#xA;&lt;p&gt;By Ultimately raising the Rainfall in the entire Southern Africa, through the managed and controlled filling and utilization of the Natural 30 000 - 60 000 square km of evaporation pans more regularly, will this not lower the extreme temperatures (day and night temperatures due to water absorbing much of the daytime heat and releasing it during the night) and drought patterns Southern Africa has experienced, and by all predictions are bound to worsen and could become more extreme?&#xA;In effect, creating a second Okavango Delta, but considerably bigger - large parts of Chobe.&lt;/p&gt;&#xA;&lt;p&gt;A study of such a magnitude will need large amounts of research in multidisciplinary sciences, from Archaeology to Agriculture to Economics, and a much broader field of expertise - the biggest being Politics!&lt;/p&gt;&#xA;&lt;p&gt;Could such a mammoth project not be but one small answer to a much bigger Climate Change challenge facing the Earth? (and ultimately send a bit of rain to my little piece of land in the Waterberg in the long dry winter months when we receive those dry West Winds - and fires become a serious hazard - simply by adding a bit of moisture from the vast pans Botswana are so blessed with!)&lt;/p&gt;&#xA;&lt;p&gt;My mind has been going in circles as to the feasibility of such a mammoth, yet so cheap and easily implementable idea?&lt;/p&gt;&#xA;&lt;p&gt;Any ideas?&lt;/p&gt;&#xA;" OwnerUserId="27005" LastEditorUserId="27005" LastEditDate="2022-06-13T20:56:32.323" LastActivityDate="2022-06-14T20:18:59.557" Title="Would the Climate change in Southern Africa by Filling Lake Makgadikgadi Evaporation Pans with water from the Zambezi and Chobe Rivers?" Tags="|climate-change|geography|rivers|rainfall|agriculture|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23914" PostTypeId="2" ParentId="23894" CreationDate="2022-06-13T17:28:37.667" Score="0" Body="&lt;p&gt;Don`t forget the clouds !&lt;br /&gt;&#xA;The cloud radiative effect (CRE) is cooling              ~ -19W/m² according to IPCC AR6 WG1 chapter 7.2.1&lt;br /&gt;&#xA;and is a net value of -47W/m² reflected solar radiation by clouds and +28W/m² absorbed thermal radiation. Not to be confused with the warming positive cloud feedback (αC = +0.42 W  m–2 °C–1) in a warmer climate due to higher clouds and decreasing low cloud cover.&#xA;&lt;a href=&quot;https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter07.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter07.pdf&lt;/a&gt;   (page 935)&lt;br /&gt;&#xA;You can read here how mankind could also cool the earth through higher evaporation and cloud cover and at the same time lower the rise in sea level.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://climate-protecion-hardware.webnode.page/english/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://climate-protecion-hardware.webnode.page/english/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;@David &amp;quot; This helps cool the troposphere as condensation is an exothermic process. &amp;quot;                                                          Condensation as an exothermic process warms the troposphere and does not cool it - as you claim.                                     The atmophere cools by outgoing thermal radiation at TOA and precipitation.&lt;/p&gt;&#xA;" OwnerUserId="26198" LastActivityDate="2022-06-13T17:28:37.667" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23915" PostTypeId="1" CreationDate="2022-06-13T18:52:54.277" Score="3" ViewCount="106" Body="&lt;p&gt;In relation to this experiment: &lt;a href=&quot;https://www.remineralize.org/rem_publications/action-of-microorganisms-in-basalt-powder/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.remineralize.org/rem_publications/action-of-microorganisms-in-basalt-powder/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It is said that applying basalt rock dust to soil can improve soil fertility especially so if a complete soil food web is present due to biological weathering by bacteria and fungi - which help to release plant nutrients into the exchangeable and soluble pool.&lt;/p&gt;&#xA;&lt;p&gt;Does basalt have a high rate of weathering and is it in the ‘discontinuous series’ or ‘continuous’ series?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Goldich_dissolution_series&quot; rel=&quot;nofollow noreferrer&quot;&gt;Goldich dissolution series&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27006" LastEditorUserId="2470" LastEditDate="2022-06-20T17:37:07.937" LastActivityDate="2022-06-20T17:37:07.937" Title="Where is basalt in the Goldich dissolution series?" Tags="|geology|geochemistry|minerals|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23916" PostTypeId="2" ParentId="23911" CreationDate="2022-06-13T23:44:30.167" Score="9" Body="&lt;p&gt;&amp;quot;Continental Drift&amp;quot; was a theory developed to explain observed phenomena (the coastline of South America and Africa being but one example). Plate tectonics, on the other hand, is the mechanism that explains how that movement is physically brought about. The latter simply supplanted the former, rather than the two being in any sort of tension.&lt;/p&gt;&#xA;" OwnerUserId="18435" LastActivityDate="2022-06-13T23:44:30.167" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23917" PostTypeId="2" ParentId="23911" CreationDate="2022-06-14T09:33:46.857" Score="18" Body="&lt;p&gt;Alfred Wegener developed his theory of continental drift in the early 20th century. His theory wasn't well accepted at that time. Geologists of that time had their own not quite scientific ideas regarding orogeny (mountain-building) and continental boundaries. Geologists of that time, along with biologists of that time, were also battling religion. This outsider (Wegener) with ideas that continents somehow plow their way through oceanic crust was not deemed plausible. In addition, his ideas were also deemed a bit too close to the mostly religious catastrophism geologists had been fighting for decades.&lt;/p&gt;&#xA;&lt;p&gt;Wegener was hardly the first to see that the continents fit together like pieces of a jigsaw puzzle. What Wegener added was fossil evidence that at some time in the past those jigsaw puzzle pieces must have fit together. What his theory did not have was a mechanism. He posited that continents somehow plow their way through or over oceanic crust. He had no mechanism.&lt;/p&gt;&#xA;&lt;p&gt;Plate tectonics, while perhaps motivated by Wegener's continental drift, is a theory distinct from continental drift. In particular, plate tectonics does have mechanisms. Before I get to those, I'll address your key concern.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;However, according to the Plate tectonics, there is much space (let's name it A) on the right-hand-side of South America and much space (let's name it B) on the left-hand-side of Africa.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;If these 2 plates were near to each other so that the two lands meet, where did the space A and B go? I think there are only 2 possibilities:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;A was over B,&lt;/li&gt;&#xA;&lt;li&gt;B was over A.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You are missing a third possibility, which is that the spaces you are calling A and B didn't always exist. This is exactly what plate tectonic theory says has happened. New oceanic crust is created by volcanism at the mid-ocean ridge. This newly formed oceanic crust is one of the key mechanisms by which continents move. Another key mechanism is subduction. Oceanic crust sinks into the mantle at subduction zones.&lt;/p&gt;&#xA;&lt;p&gt;These two mechanisms mean that most oceanic crust is fairly young, less than 200 million years old. The oldest oceanic crust is probably the Herodotus Basin in the Mediterranean Sea, estimated to be about 340 million years old. In many ways, it's best to view the Mediterranean Sea as a remnant of the old Tethys Ocean rather than as an arm of the Atlantic Ocean.&lt;/p&gt;&#xA;&lt;p&gt;The space we currently see between South America and Africa did not exist when the supercontinent Pangaea existed. Rift valleys formed that started to split the supercontinent into pieces. These rift valleys eventually became the sites of new oceanic ridges, and the space between the split-apart continents became new ocean such as the Atlantic Ocean.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-06-14T09:33:46.857" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23918" PostTypeId="2" ParentId="23915" CreationDate="2022-06-14T10:10:48.657" Score="2" Body="&lt;p&gt;The Goldich series does not contain rocks such as basalt. It contains the minerals that make up the rocks, generally igneous rocks such as basalt. Thus we have to be somewhat general, but we should expect to see basalt in the &lt;strong&gt;upper range of the Goldich series.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;As with most rocks, the mixture of minerals includes &lt;strong&gt;both continuous and discontinuous components&lt;/strong&gt; in the series.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Felsic vs mafic&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Igneous rocks commonly found at the surface are classified as &lt;strong&gt;felsic&lt;/strong&gt; or &lt;strong&gt;mafic&lt;/strong&gt;, which correlates with their silica content: felsic is higher silica an mafic is lower silica. The latter corresponds to minerals that are higher on the Goldich series, such as pyroxenes.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;The big reveal: basalt is mafic&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;So basalt, being a rock, does not have its own entry in the Goldich series, but &lt;strong&gt;it is the classic example of a mafic rock.&lt;/strong&gt; Therefore relatively low silica, and high on the Goldich series. A typical weight-percent composition is given by Shrivasta et al. &lt;a href=&quot;https://www.researchgate.net/figure/Composition-of-basalt-in-wt_tbl3_301348713&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kxbYv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kxbYv.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The silica level is similar to that in pyroxenes and in calcium-rich plagioclase feldspar (which are themselves major component minerals in basalt), so we should expect basalt to appear in the upper range of the Goldich series. Since basalt contains both pyroxenes and feldspar, it has both discontinuous and continuous components.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Shrivastava, J. &amp;amp; Rani, Nishi &amp;amp; Pathak, Vamdev. (2016). &amp;quot;Geochemical Modeling and Experimental Studies on Mineral Carbonation of Primary Silicates for Long-term Immobilization of CO 2 in Basalt from the Eastern Deccan Volcanic Province.&amp;quot; &lt;em&gt;Journal Indian Geophysical Union&lt;/em&gt;. Special volume -1. 42-58.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2022-06-14T12:35:23.663" LastActivityDate="2022-06-14T12:35:23.663" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23919" PostTypeId="2" ParentId="23915" CreationDate="2022-06-14T11:52:29.317" Score="2" Body="&lt;p&gt;To answer the other parts of you question, the main minerals composing &lt;a href=&quot;https://en.wikipedia.org/wiki/Basalt&quot; rel=&quot;nofollow noreferrer&quot;&gt;basalt&lt;/a&gt; are calcic plagioclase &lt;a href=&quot;https://en.wikipedia.org/wiki/Feldspar&quot; rel=&quot;nofollow noreferrer&quot;&gt;feldspar&lt;/a&gt;, amphibole, and pyroxene. Olivine can be also be a significant constituent. The two main minerals are plagioclase and pyroxene. Plagioclase is in the continuous series, whereas pyroxene and amphibole are in the discontinuous serious.&lt;/p&gt;&#xA;&lt;p&gt;There are two types of basalt:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Tholeiitic basalt&lt;/strong&gt; which contains pyroxene (augite and orthopyroxene&#xA;or pigeonite) and calcium-rich plagioclase are common &lt;a href=&quot;https://en.wikipedia.org/wiki/Phenocryst&quot; rel=&quot;nofollow noreferrer&quot;&gt;phenocryst&lt;/a&gt;&#xA;minerals. Olivine may also be a phenocryst. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Matrix_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;groundmass&lt;/a&gt;, or matrix,contains interstitial quartz or tridymite or cristobalite&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Alkali basalt&lt;/strong&gt; which contains mineral assemblages that lack&#xA;orthopyroxene but contain olivine.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Regarding &lt;a href=&quot;https://en.wikipedia.org/wiki/Basalt#Weathering&quot; rel=&quot;nofollow noreferrer&quot;&gt;weathering of basalt&lt;/a&gt;, basalt on the surface of the Earth weathers rapidly. Because of the low potassium content of most basalts, weathering converts the basalt to calcium-rich clay (montmorillonite) rather than potassium-rich clay (illite).&lt;/p&gt;&#xA;&lt;p&gt;Chemical weathering also releases readily water-soluble cations such as calcium, sodium and magnesium, which give basaltic areas a strong buffer capacity against acidification. Calcium released by basalts binds CO&lt;sub&gt;2&lt;/sub&gt; from the atmosphere forming CaCO&lt;sub&gt;3&lt;/sub&gt; acting thus as a CO&lt;sub&gt;2&lt;/sub&gt; trap.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-06-14T11:52:29.317" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23920" PostTypeId="1" CreationDate="2022-06-14T14:03:51.457" Score="2" ViewCount="34" Body="&lt;p&gt;Are natural or artificial pools of water (like ponds) carbon positive, negative or neutral? They store carbon, but anaerobes release methane, don't they?&lt;/p&gt;&#xA;" OwnerUserId="22632" LastActivityDate="2022-06-14T14:03:51.457" Title="Are natural or artificial pools of water (like ponds) carbon positive, negative or neutral?" Tags="|climate-change|carbon-cycle|carbon-capture|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23921" PostTypeId="2" ParentId="23913" CreationDate="2022-06-14T20:18:59.557" Score="-1" Body="&lt;p&gt;We agree that additional evaporation enhances energy transport from the surface to the atmosphere and intensifies the hydrological cycle and cloud formation, and that some of the most serious climate change issues such as:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Rapidly expanding deserts with forest and species extinction&lt;/li&gt;&#xA;&lt;li&gt;Accelerated rising sea level and earth temperature&lt;/li&gt;&#xA;&lt;li&gt;In many places sinking groundwater levels, drainage of the regions and continents&#xA;-Periods of drought with temperature records and heavy rain events with flooding&#xA;…are all linked to the presence or absence of water !&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;You can read here what a slightly modified concept for reducing sea level rise through water and rain retention and for cooling the Earth's temperature through additional cloud albedo could look like: &lt;a href=&quot;https://climate-protecion-hardware.webnode.page/english/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://climate-protecion-hardware.webnode.page/english/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26198" LastActivityDate="2022-06-14T20:18:59.557" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23922" PostTypeId="1" CreationDate="2022-06-14T23:21:50.573" Score="1" ViewCount="95" Body="&lt;p&gt;All,&#xA;The static stability of the atmosphere is defined as:&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$\sigma =-\dfrac{T}{\theta} \dfrac{d\theta}{dp}= \dfrac{dT}{dp}-\dfrac{R}{c_p} \dfrac{T}{p}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where:&#xA;&lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; is temperature,&#xA;&lt;span class=&quot;math-container&quot;&gt;$P$&lt;/span&gt; is pressure,&#xA;&lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; is ideal gas constant,&#xA;&lt;span class=&quot;math-container&quot;&gt;$c_p$&lt;/span&gt; is heat capacity at constant pressure,&#xA;&lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; is potential temperature, which is defined as &lt;span class=&quot;math-container&quot;&gt;$\theta=T \left(\dfrac{p_o}{p}\right)^{R/c_p}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$p_0$&lt;/span&gt; is reference pressure.&lt;/p&gt;&#xA;&lt;p&gt;The calculated statics stability using &lt;span class=&quot;math-container&quot;&gt;$\dfrac{dT}{dp}-\dfrac{R}{c_p} \dfrac{T}{p}$&lt;/span&gt; or &lt;span class=&quot;math-container&quot;&gt;$-\dfrac{T}{\theta} \dfrac{d\theta}{dp}$&lt;/span&gt; should be identical, yet they actually differ sometimes as shown below&#xA;&lt;a href=&quot;https://i.stack.imgur.com/6vGTm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6vGTm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://app.box.com/s/ryzrgd7txr16qizt3fandjp65sqamhg8&quot; rel=&quot;nofollow noreferrer&quot;&gt;(plz see attached Python code used to calculated statics stability )&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I am wondering if there is analytical or numerical way to determine when both identical definition of static stability might diverge, though? Sometimes, the way that terms is calculated numerically can significantly change the results, for example, the physical properties of the Jacobian of the 2D advection equation was found to differ based on the numerical technique used in the calculation &lt;a href=&quot;https://people.bath.ac.uk/ensdasr/PAPERS/arakawa_1966.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;see Arakawa (1966)&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6541" LastActivityDate="2023-04-12T14:03:50.463" Title="divergence of static stability identical parameters" Tags="|meteorology|atmosphere|atmosphere-modelling|numerical-modelling|thermodynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23923" PostTypeId="2" ParentId="23907" CreationDate="2022-06-15T03:25:26.947" Score="1" Body="&lt;p&gt;The impacts of global warming on weather patterns are complex, but include the continuing potential for extreme weather events at local and regional scales, including extreme cold events from polar air being driven to lower latitudes.&lt;/p&gt;&#xA;&lt;p&gt;Weather patterns that cause cold air masses to move to lower latitudes include disruptions to the Polar Vortex. The Polar Vortex is a strong pole circling stratospheric wind pattern that occurs in Winter; it tends to keep cold Arctic air close to the pole. When it is disrupted the winds weaken and meander North and South more causing both extreme heat and extreme cold events.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/DlWhq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DlWhq.png&quot; alt=&quot;Polar Vortex&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Why the Polar Vortex gets disrupted is still being studied but it is hypothesized that Polar Amplification, where loss of Arctic sea ice causes more heat to be absorbed by Arctic waters and causes heat to persist longer and Arctic air temperatures to rise more than the global average plays a part and is increasing the frequency of Polar Vortex disruption. It is thought the mechanism is that this warmer than normal (but still very cold) Arctic air rises and disrupts the Polar Vortex, which in turn allows cold Arctic air masses to spill further South than usual and warm air to spill further North.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2022-06-15T03:25:26.947" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23924" PostTypeId="2" ParentId="23904" CreationDate="2022-06-15T09:38:59.203" Score="5" Body="&lt;p&gt;It looks like you simply messed up the order of your min and max of the latitude. And you were looking at the wrong place (-44° instead of +44°).&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;# bathymetry&#xA;import numpy as np&#xA;import matplotlib.pyplot as plt&#xA;from netCDF4 import Dataset&#xA;&#xA;data = Dataset(&amp;quot;ETOPO1_Bed_g_gmt4.grd&amp;quot;,'r')&#xA;&#xA;lon_range = data.variables['x_range'][:]&#xA;lat_range = data.variables['y_range'][:]&#xA;topo_range = data.variables['z_range'][:]&#xA;spacing = data.variables['spacing'][:]&#xA;dimension = data.variables['dimension'][:]&#xA;z = data.variables['z'][:]&#xA;lon_num = dimension[0]&#xA;lat_num = dimension[1]&#xA;&#xA;lon = np.linspace(lon_range[0],lon_range[1],dimension[0])&#xA;lat = np.linspace(lat_range[0],lat_range[1],dimension[1])&#xA;&#xA;topo = np.reshape(z, (lat_num, lon_num))&#xA;&#xA;# Select region&#xA;lon_idx_min = np.abs(lon-10).argmin() # I increased the margin a little&#xA;lon_idx_max = np.abs(lon-20).argmin() # to better see where the region is&#xA;lat_idx_min = np.abs(lat+48).argmin()&#xA;lat_idx_max = np.abs(lat+40).argmin()&#xA;&#xA;plt.imshow(topo[lat_idx_min:lat_idx_max, lon_idx_min:lon_idx_max], vmax=0)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;By using np.linspace you can remove the loop from your code and speed it up significantly.&#xA;There is no need to create a meshgrid from lat and lon.&lt;/p&gt;&#xA;" OwnerUserId="26870" LastActivityDate="2022-06-15T09:38:59.203" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23925" PostTypeId="1" CreationDate="2022-06-15T16:09:27.077" Score="2" ViewCount="42" Body="&lt;p&gt;In river morphology, a &lt;a href=&quot;https://en.wikipedia.org/wiki/Plunge_pool&quot; rel=&quot;nofollow noreferrer&quot;&gt;plunge pool&lt;/a&gt; is a (small) lake formed at the bottom of a waterfall.&lt;/p&gt;&#xA;&lt;p&gt;In German, there exists the word &lt;a href=&quot;https://de.wikipedia.org/wiki/Gumpe&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Gumpe&lt;/em&gt;&lt;/a&gt;, apparently from Bavarian.  From the German language Wikipedia, a &lt;em&gt;Gumpe&lt;/em&gt; is a &lt;em&gt;überwiegend beckenartige Strudeltopfe, die von Sturzbächen in den felsigen Untergrund eines Bachbetts erodiert werden&lt;/em&gt;, which may be translated as &lt;em&gt;predominantly basin-like [swirl pot] eroded by torrents into the rocky bedrock of a streambed&lt;/em&gt; (I'm not sure how to translate &lt;em&gt;Strudeltopf&lt;/em&gt;).  The sources cited by Wikipedia are from 1887 and 1935.&lt;/p&gt;&#xA;&lt;p&gt;The description of &lt;em&gt;Gumpe&lt;/em&gt; seems quite similar to the description of a &lt;em&gt;plunge pool&lt;/em&gt;, but the German language Wikipedia article on &lt;em&gt;Gumpe&lt;/em&gt; has only one interlanguage link, to a Bavarian entry.  The English language Wikipedia article on &lt;em&gt;plunge pool&lt;/em&gt; has no interlanguage link to German.&lt;/p&gt;&#xA;&lt;p&gt;Is a &lt;em&gt;Gumpe&lt;/em&gt; the same as a &lt;em&gt;plunge pool&lt;/em&gt; or is there a difference?  Is a &lt;em&gt;Gumpe&lt;/em&gt; a specific type of &lt;em&gt;plunge pool&lt;/em&gt;, or something quite different?&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2022-06-15T16:09:27.077" Title="Is a Gumpe the same as a plunge pool or stream pool?" Tags="|rivers|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23927" PostTypeId="2" ParentId="23911" CreationDate="2022-06-16T10:58:43.720" Score="6" Body="&lt;p&gt;I just wanted to augment the other answers with some pictures. Not only there isn't a contradiction, but plate tectonics &lt;em&gt;confirms and explains&lt;/em&gt; continental drift. It's the mechanism by which continental drift happens.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cHmnu.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cHmnu.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The oceanic crust between South America and Africa didn't exist when the two continents were joined. It is younger than both continents, and it is spreading away from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mid-Atlantic_Ridge&quot; rel=&quot;noreferrer&quot;&gt;Mid-Atlantic Ridge&lt;/a&gt; even today. Note that the ridge itself has a similar shape to the continent outlines. This is termed a divergent plate boundary.&lt;/p&gt;&#xA;&lt;p&gt;The youngest part of the oceanic crust is at the center (near the ridge), and it gets older and older as you move away towards the continent on either side. So at the center, it's very recent, while at the edges its hundreds of millions of years old (mostly &amp;lt; 200 Myr).&lt;/p&gt;&#xA;&lt;p&gt;In contrast, the average age of the continental crust is about 2 &lt;em&gt;billion&lt;/em&gt; years, with some parts of continents having been there for more than 4 billion years (so 10-20+ times older).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WOIbZ.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WOIbZ.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The oceanic crust is, in general, actually moving apart faster than the continents themselves. Because oceanic crust is made up of denser material, it is heavier than the continental crust, so at the ocean-continent plate boundary, the oceanic crust sinks &lt;em&gt;under&lt;/em&gt; the continent and &amp;quot;flows&amp;quot; down into the mantle (part of the Earth that's under the crust) in a process known as subduction. The oceanic crust is destroyed (melted) within the mantle. Deep  ocean trenches, like the famous (Mariana Trench) mark the subduction zones.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VAfo7.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VAfo7.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;P.S. An example of a relatively young divergent boundary is the Red Sea; the spreading apart of the African Plate and the Arabian Plate created the Red Sea basin.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lGTJi.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lGTJi.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;See also:&lt;br /&gt;&#xA;More info on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Red_Sea_Rift&quot; rel=&quot;noreferrer&quot;&gt;Red Sea Rift&lt;/a&gt;&lt;br /&gt;&#xA;For an example of a plate currently in the process of splitting into two new plates: &lt;a href=&quot;https://en.wikipedia.org/wiki/East_African_Rift&quot; rel=&quot;noreferrer&quot;&gt;East African Rift&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21806" LastActivityDate="2022-06-16T10:58:43.720" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23929" PostTypeId="1" CreationDate="2022-06-17T07:49:32.253" Score="3" ViewCount="92" Body="&lt;p&gt;Hi I was wondering how fast the climate zones (according to W. Köppen) have shifted in the last 22 years. It is well known that the zones shift about 100-200 km to the north or south for each degree Celsius increase in air temperature! Are there any current studies that prove this since the turn of the millennium, or is this a period that is too short to be representative?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="2470" LastEditDate="2022-06-17T19:11:01.533" LastActivityDate="2022-06-17T19:11:01.533" Title="How quickly climate zones are shifting due to climate change!" Tags="|climate-change|climate|climate-models|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23930" PostTypeId="2" ParentId="13793" CreationDate="2022-06-17T17:40:03.397" Score="1" Body="&lt;p&gt;Just like you, I've been searching for such a video of the cloud cover. I didn't want to mess with the tons of images that NASA provides (and with the blank spot drawbacks that Camilo Rada mentioned in his answer) in order to create my own video, and all I could find were simulations where the cloud cover was not the only layer in the video.&lt;/p&gt;&#xA;&lt;p&gt;In other words, instead of the black and white system for the frames (that can easily be applied to a custom made globe as an &amp;quot;alpha map video&amp;quot; via libraries such as Three.js), all I could find were videos presenting the final result, where the BW alpha mask was already applied to the Earth map and projected on the sphere.&lt;/p&gt;&#xA;&lt;p&gt;Luckily, today I found that NASA provides just what you and I wanted ... assuming one knows what to look for. The description of the contents is not that intuitive if you only focus on getting a cloud cover animation, but it's available at NASA/Goddard Space Flight Center Scientific Visualization Studio's &lt;a href=&quot;https://svs.gsfc.nasa.gov/3837&quot; rel=&quot;nofollow noreferrer&quot;&gt;Components of the Water Cycle on a Flat Map for Science On a Sphere&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The animation you're looking for is the first in the list, i.e. the &amp;quot;global cloud cover on a flat map with transparency&amp;quot;, like you can see from the screenshot below (the animation simulates just one month, but it's enough and also compact for most things):&#xA;&lt;img src=&quot;https://i.stack.imgur.com/YgwP8.jpg&quot; alt=&quot;NASA - Components of the Water Cycle on a Flat Map for Science On a Sphere&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;Or, you could use what I also used before finding the above accurate cloud movement, the &lt;a href=&quot;https://vimeo.com/120179542&quot; rel=&quot;nofollow noreferrer&quot;&gt;Free 4K Animated Cloud Layer for 3D Planet Earth Models&lt;/a&gt; posted on Vimeo. The only drawback for this one is that the cloud movement is not replicated according to a realistical Earth model (i.e. clouds spiralling towards NE in the Northern hemisphere, towards SE in the Southern hemisphere, and towards W along the Equator), which is why I preferred the NASA provided alternative.&lt;/p&gt;&#xA;" OwnerUserId="27029" LastActivityDate="2022-06-17T17:40:03.397" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23931" PostTypeId="1" CreationDate="2022-06-17T21:37:39.897" Score="1" ViewCount="24" Body="&lt;p&gt;I am using VIs such as NDVI, RENDVI, SAVI, SAVI2 etc.&lt;/p&gt;&#xA;&lt;p&gt;What I cannot understand is what do the values that I read stand for. It is not obvious, and it is logic, because each VI is made of different equation, so represents a different meaning.&lt;/p&gt;&#xA;&lt;p&gt;How can I &amp;quot;decode&amp;quot; VIs?&lt;/p&gt;&#xA;&lt;p&gt;Is there a rule to follow?&lt;/p&gt;&#xA;&lt;p&gt;I found topics like this: &lt;a href=&quot;https://gis.stackexchange.com/questions/322416/understanding-why-msavi-ii-values-are-outside-the-theoretical-range&quot;&gt;https://gis.stackexchange.com/questions/322416/understanding-why-msavi-ii-values-are-outside-the-theoretical-range&lt;/a&gt; but I cannot say it helped.&lt;/p&gt;&#xA;" OwnerUserId="27033" LastActivityDate="2022-06-17T21:37:39.897" Title="Understanding Vegetation Indices values" Tags="|vegetation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23932" PostTypeId="2" ParentId="6843" CreationDate="2022-06-18T06:13:37.793" Score="1" Body="&lt;p&gt;I am using &amp;quot;PARI&amp;quot; a free open source math program for Mac or PC,&#xA;for these exact (vs GRS80 Ellipsoid) equations:&#xA;&amp;quot;longscale&amp;quot;gives meters per (second of Longitude) at a constant latitude,&#xA;so below I multiply it by &amp;quot;3.6&amp;quot; to get&#xA;vs 0.001 degrees as requested by the original poster:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;re=6378137;\&#xA;flattening=298.2572221008827112431628366;\&#xA;a=(1-1/flattening)^2;\&#xA;reh= (put 6378137 meters plus your height above the ellipsoid here)&#xA;&#xA;longscale(u)=1/sqrt(1 + a *(1/(cos(u))^2 - 1))*reh*2*Pi/60^4*10;&#xA;longscale(((00/60+00)/60+30)*Pi/180)*3.6&#xA;%452 = 96.4862802512923113&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Latitude is harder because as the arc gets bigger the scale&#xA;changes, whereas scale stays exactly the same along constant latitudes.&#xA;So say the OP also wanted the distance from 30degrees &lt;em&gt;latitude&lt;/em&gt; to 30.001.&#xA;Then either of the following integrals give the same answer,&#xA;but might have different speeds or accuracy in your computer language:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;fl=flattening;\&#xA;&#xA;ma1(lat)=e2=1-(1-1/fl)^2;\&#xA;(1-1/fl)^2*intnum(th=0,lat,1/(1-e2*(sin(th))^2)^(3/2))*reh&#xA;&#xA;ma4(lat)=e2=1-(1-1/fl)^2;\&#xA;(intnum(th=0,lat,sqrt(1-e2*(sin(th))^2));\&#xA;-e2/2*sin(2*lat)/sqrt(1-e2*(sin(lat))^2))*reh&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Thus the distance&#xA;is the meridian arc length of the second point minus&#xA;the meridian arc length of the first:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;lat1=((00/60+00)/60+30)*Pi/180;\&#xA;lat2=((3.6/60+00)/60+30)*Pi/180;\&#xA;ma4(lat2)-ma4(lat1)&#xA;cpu time = 195 ms, real time = 196 ms.&#xA;%456 = 110.852450919981499&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;If he likewise wanted the scale at 30 degrees Latitude in&#xA;meters per (second of Latitude),&#xA;then differentiate the equation above like this:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;lat1=((00/60+00)/60+30)*Pi/180;\&#xA;derivnum(lat=lat1,ma4(lat))*Pi/60^4*20&#xA;cpu time = 648 ms, real time = 649 ms.&#xA;%455 = 30.7923451370347380&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="27036" LastActivityDate="2022-06-18T06:13:37.793" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23933" PostTypeId="1" AcceptedAnswerId="23934" CreationDate="2022-06-19T01:30:17.603" Score="7" ViewCount="791" Body="&lt;p&gt;In Pangaea, northern Africa would have had humid onshore winds from the Tethys Ocean, making dense vegetation/rainforest biome likely.&lt;/p&gt;&#xA;&lt;p&gt;Consequently, would we be likely to find coal underneath the Sahara desert?&lt;/p&gt;&#xA;" OwnerUserId="27040" LastEditorUserId="2470" LastEditDate="2022-06-20T09:06:09.943" LastActivityDate="2022-06-20T09:06:09.943" Title="Is there likely to be coal under the Sahara?" Tags="|earth-history|mining|resources|coal|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23934" PostTypeId="2" ParentId="23933" CreationDate="2022-06-19T04:37:10.177" Score="11" Body="&lt;p&gt;The older rocks underlying the &lt;a href=&quot;https://geography.name/the-geology-of-the-sahara/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sahara&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;are mostly granite, schist, or gneiss, all mixtures of igneous and metamorphic rocks forged deep beneath the surface&lt;/p&gt;&#xA;&lt;p&gt;This stable mass of rock has been covered over with younger sediments, laid down in horizontal, largely unaltered layers. &lt;strong&gt;Much of the Sahara is covered with limestone&lt;/strong&gt;, made mostly of the skeletons of microscopic sea creatures raining down onto the bottom of a vanished sea.&lt;/p&gt;&#xA;&lt;p&gt;Most of the limestone and sandstone covering the surface of the Sahara were deposited in the Mesozoic era (245–65 million years ago).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;From the &lt;a href=&quot;https://pubs.usgs.gov/of/2008/1258/graphics/Africa_Coal.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;picture below&lt;/a&gt;, produced by the US Geological Survey, most of Africa's coal deposits are in the southern part of the continent. There appears to be a very minor coal deposit in western Algeria with other similar sized deposits in Niger, Mali and Sudan. Egypt's Sinai appears to have an exceedingly small deposit of coal from the Jurassic period.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://pubs.usgs.gov/of/2008/1258/graphics/Africa_Coal.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://pubs.usgs.gov/of/2008/1258/graphics/Africa_Coal.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;In terms of hydrocarbon resources, the Sahara contains about &lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/african-plate&quot; rel=&quot;nofollow noreferrer&quot;&gt;4 percent of the worlds current reserves of oil and gas&lt;/a&gt;. In terms of energy resources, &amp;quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Energy_in_Africa&quot; rel=&quot;nofollow noreferrer&quot;&gt;North Africa is dominant in oil and gas&lt;/a&gt;&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ttPR1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ttPR1.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2022-06-20T08:54:46.587" LastActivityDate="2022-06-20T08:54:46.587" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23935" PostTypeId="1" AcceptedAnswerId="23937" CreationDate="2022-06-19T09:18:38.670" Score="10" ViewCount="3692" Body="&lt;p&gt;Took some sulfur stones while hiking on a volcano. Keeping them at home as a piece of decore. Is it safe to store it on a shelf? Can it ignite or somehow do harm to me or to my pets?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/LdFIp.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LdFIp.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27042" LastEditorUserId="2470" LastEditDate="2022-06-20T17:33:42.230" LastActivityDate="2022-08-01T08:23:10.650" Title="Is it safe to keep volcanic sulfur at home?" Tags="|geology|minerals|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23936" PostTypeId="1" CreationDate="2022-06-19T09:44:14.140" Score="2" ViewCount="480" Body="&lt;p&gt;Today when I woke up there was fog in the air and it smelled like smoke, I thought the fog was water vapor since the temperature was 47‎°C ( I know that's crazy hot), but then when I saw the weather forecast it turned out that the weather is “smokey” today!&lt;/p&gt;&#xA;&lt;p&gt;I didn't even know that there was such thing as smokey weather, I don't think there were any major fires that occurred last night, the city where I live is pretty much a dry desert, there are no mountains and not many plants, there are rivers however, what's strange is that it's never happened before, so what could cause that? Is the city starting to smoke due to high temperature? Is it the smoke of factories? Is it oil vapor(I don't think smoke and oil vapor are the same thing) ?&lt;/p&gt;&#xA;" OwnerUserId="27044" LastEditorUserId="27044" LastEditDate="2022-06-20T04:32:32.220" LastActivityDate="2022-06-21T09:23:05.867" Title="What causes &quot;Smokey&quot; weather?" Tags="|meteorology|extreme-weather|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23937" PostTypeId="2" ParentId="23935" CreationDate="2022-06-19T10:53:55.107" Score="15" Body="&lt;p&gt;&lt;strong&gt;Short answer:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Assuming it is sulfur (likely, but I'm not addressing other compounds in this answer) you should be fine as long as you keep it away from heat (melts at a low temperature and is somewhat flammable).&lt;/p&gt;&#xA;&lt;p&gt;I've had a chunk of sulfur in my house for about 40 years and never had an issue with it.  I'm pretty sure most of the cleaning products in the house are more dangerous.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Long(er) answer:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;From the sulfur MSDS (&lt;a href=&quot;https://www.teck.com/media/Sulfur.pdf&quot; rel=&quot;noreferrer&quot;&gt;PDF&lt;/a&gt;):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Sulphur is relatively non-toxic to humans, causing only mild local&#xA;irritation to the eyes, nose, throat and upper airways. However, under&#xA;certain circumstances it may release toxic hydrogen sulphide and/or&#xA;sulphur dioxide gas. Sulphur is not listed as a carcinogen by OSHA,&#xA;NTP, IARC or ACGIH.&lt;/p&gt;&#xA;&lt;p&gt;Both molten and solid forms are combustible and will ignite at high&#xA;temperatures (&amp;gt;200°C), burning with a pale blue flame that may be&#xA;difficult to see in daylight. Sulphur dust suspended in air ignites&#xA;easily and can cause explosions in confined spaces. Sulphur dust&#xA;clouds can be ignited by friction, static electricity, heat, sparks or&#xA;flames. Traces of hydrogen sulphide and sulphur vapor may present an&#xA;explosion hazard if evolved into a confined space or enclosed space,&#xA;particularly from molten sulphur. The LEL of hydrogen sulphide (4.3%&#xA;by volume in air) may be exceeded in enclosed spaces above molten&#xA;sulphur.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;See also the &lt;a href=&quot;https://en.wikipedia.org/w/index.php?title=Sulfur&amp;amp;oldid=1092444175#Precautions&quot; rel=&quot;noreferrer&quot;&gt;precautions&lt;/a&gt; section on Wikipedia.&lt;/p&gt;&#xA;" OwnerUserId="18088" LastActivityDate="2022-06-19T10:53:55.107" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23938" PostTypeId="2" ParentId="23936" CreationDate="2022-06-20T00:17:04.537" Score="5" Body="&lt;p&gt;One possible cause will be an &lt;a href=&quot;https://en.wikipedia.org/wiki/Inversion_(meteorology)&quot; rel=&quot;noreferrer&quot;&gt;inversion&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Normally, air temperature decreases with an increase in altitude, but during an inversion warmer air is held above cooler air.&lt;/p&gt;&#xA;&lt;p&gt;An inversion traps air pollution, such as smog, close to the ground. An inversion can also suppress convection by acting as a &amp;quot;cap&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Cities especially suffer from the effects of temperature inversions because they both produce more atmospheric pollutants and have higher thermal masses than rural areas, resulting in more frequent inversions with higher concentrations of pollutants. The effects are even more pronounced when a city is surrounded by hills or mountains since they form an additional barrier to air circulation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-06-20T00:17:04.537" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23939" PostTypeId="1" AcceptedAnswerId="23940" CreationDate="2022-06-20T09:44:54.877" Score="3" ViewCount="88" Body="&lt;p&gt;I am working on a table of data from a chart that appears in the IPCC AR6 WG1 report, &lt;a href=&quot;https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_Chapter05.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Carbon and Other Biogeochemical Cycles and Feedbacks-Chapter 5&lt;/a&gt;, &lt;strong&gt;Figure 5.12&lt;/strong&gt; | &lt;code&gt;Global carbon (CO2) budget (2010–2019)&lt;/code&gt; on page 700.&lt;/p&gt;&#xA;&lt;p&gt;I must admit from the outset that I have not, nor do I intend to, read the entire report. I am, however, searching to see if someone more familiar with &lt;strong&gt;Figure 5.12&lt;/strong&gt; who can provide a bit more of an explanation of the details presented in &lt;strong&gt;Figure 5.12&lt;/strong&gt;. Also, I am NOT a climate scientist, so apologies in advance if my questions are readily apparent to those more familiar with the science.&lt;/p&gt;&#xA;&lt;p&gt;Quick key: &lt;a href=&quot;https://i.stack.imgur.com/3pLxs.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3pLxs.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Specifically, I would like to understand more about the CO2 fluxes to and from the atmosphere that are nicely summarized toward the top of the chart:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/195r3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/195r3.png&quot; alt=&quot;carbon fluxes (in PgC yr–1) to/from the atmosphere&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question 1&lt;/strong&gt;: The carbon fluxes shown toward the left side, beneath &lt;code&gt;Net land flux&lt;/code&gt; display two values alongside &lt;code&gt;Gross photosynthesis&lt;/code&gt; of &lt;code&gt;113&lt;/code&gt; (orange) and &lt;code&gt;29&lt;/code&gt; (red). I assume that &lt;code&gt;Gross photosynthesis&lt;/code&gt; refers to GPP (as opposed to Net primary Production or NPP) but I'm puzzled as to what the &lt;code&gt;29&lt;/code&gt; (red) refers to. Both the &lt;code&gt;113&lt;/code&gt; (orange) and &lt;code&gt;29&lt;/code&gt; (red) point toward the earth indicating carbon flux &lt;em&gt;&lt;strong&gt;away&lt;/strong&gt;&lt;/em&gt; from the atmosphere (e.g. reducing carbon in the atmosphere) which I understand happens with &lt;strong&gt;Naturally&lt;/strong&gt; occurring photosynthesis. The &lt;code&gt;29&lt;/code&gt; (red), however, indicates an &lt;strong&gt;anthropogenic&lt;/strong&gt; activity, purportedly related to &lt;code&gt;Gross photosynthesis&lt;/code&gt; that &lt;em&gt;reduces&lt;/em&gt; carbon in the atmosphere. I'm puzzled as to what that &lt;code&gt;29&lt;/code&gt; (red) may be.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question 2&lt;/strong&gt;: Similar to the carbon fluxes shown on the left side, beneath &lt;code&gt;Net land flux&lt;/code&gt;, I'd like to know more about what constitutes the carbon fluxes shown on the right side, beneath &lt;code&gt;Net ocean flux&lt;/code&gt;. Here I am looking for any information on the carbon flux that makes up the &lt;code&gt;Ocean-atmosphere gas exchange&lt;/code&gt;, including the carbon flux &lt;em&gt;&lt;strong&gt;toward&lt;/strong&gt;&lt;/em&gt; the atmosphere of &lt;code&gt;54.6&lt;/code&gt; (orange) and &lt;code&gt;23&lt;/code&gt; (red) (e.g. increasing carbon in the atmosphere), and the flux &lt;em&gt;&lt;strong&gt;away from&lt;/strong&gt;&lt;/em&gt; the atmosphere of &lt;code&gt;54.0&lt;/code&gt; (orange) and &lt;code&gt;25.5&lt;/code&gt; (red) (e.g. reducing carbon in the atmosphere).&lt;/p&gt;&#xA;&lt;p&gt;Excerpts or simply page numbers in the report where I may learn more about the above numbers would be greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="27048" LastActivityDate="2022-06-21T13:42:17.883" Title="Looking for details on data presented in IPCC AR6 WG1 report" Tags="|carbon-cycle|carbon|natural-conditions|anthropogenic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23940" PostTypeId="2" ParentId="23939" CreationDate="2022-06-20T13:16:24.730" Score="3" Body="&lt;p&gt;Oh dear, I agree that this is a poorly explained figure.  Let's look at the caption:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Yellow arrows represent annual carbon fluxes (in PgC yr–1) associated with the natural carbon cycle, estimated for the time prior to the industrial era, around 1750. Pink arrows represent anthropogenic fluxes averaged over the period 2010–2019.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I don't think that second sentence is correct.  My interpretation is that the pink arrows are the anthropogenic &lt;em&gt;perturbation&lt;/em&gt; of the natural carbon cycle that give us the observed present-day fluxes.  They're not meant to represent separate processes from the more obviously labelled yellow arrows.&lt;/p&gt;&#xA;&lt;p&gt;So, total respiration and fire emissions were 111.1 PgC/yr in 1750 and are 111.1+25.6=136.7 PgC/yr in the present day.  Similarly, gross photosynthesis was 113 PgC/yr in 1750 and is 113+29=142 PgC/yr in the present day, which represents approximately a 25% enhancement (due mainly to CO2 fertilization).  That fits with some text in the Fig 5.12 caption from an earlier draft of the report:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The relative change of Gross photosynthesis since pre-industrial times is&#xA;estimated as the range of observation-based of 31 ± 3 % (Campbell et al., 2017) and land-model of 19±12% (Sitch et al., 2015) estimates. This is used to estimate the pre-industrial Gross photosynthesis, assuming a present-day range of 116–175 PgC yr-1 (Joiner et al., 2018). The corresponding emissions by Total respiration and fire are those required to match the Net land flux...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Note that most of those pink values on the net fluxes row come from Friedlingstein et al (2020), who describe them as &amp;quot;&lt;em&gt;the overall perturbation of the global carbon cycle caused by anthropogenic activities&lt;/em&gt;&amp;quot;.  Where I think this figure differs from Friedlingstein et al slightly is that it imposes closure of the cumulative 1750 to 2019 carbon fluxes (see column 1 of Table 5.1), which means that the budgetary imbalance of 20 PgC going back to 1850 is assigned to the pre-industrial land and ocean sinks.&lt;/p&gt;&#xA;&lt;p&gt;Re the oceans, in some ways this is a simpler case than the land.  All parts of the ocean are continually exchanging CO2 with the atmosphere: some CO2 molecules dissolve into surface waters (entering through diffusion or bubble entrainment and collapse), and some CO2 molecules outgas from surface waters (leaving through diffusion or bubble cavitation).  Figure 5.12 shows estimates of those gross fluxes in 1750 in yellow: 54.0 PgC/yr entering the ocean and 54.6 PgC/yr leaving the ocean, giving a net loss from the ocean to atmosphere of 0.6 PgC/yr.&lt;/p&gt;&#xA;&lt;p&gt;Anthropogenic emissions have perturbed the system so that there are now gross CO2 fluxes of 54.0+25.5=79.5 PgC/yr entering and 54.6+23.0=77.6 PgC/yr leaving the ocean, giving a net &lt;em&gt;gain&lt;/em&gt; of CO2 by the ocean of -0.6+2.5=1.9 PgC/yr.  Both of those gross fluxes have increased because the CO2 concentrations in the atmosphere and surface ocean have both increased but, on average, the atmospheric concentration has increased more.  This produces a gradient in CO2 concentration across the atmosphere-ocean interface that drives the net flux into the ocean.  This gradient is maintained partly by continued fossil fuel emissions into the atmosphere and partly by physical and biological ocean processes that transfer dissolved CO2 down away from the surface into deeper ocean waters.&lt;/p&gt;&#xA;" OwnerUserId="106" LastEditorUserId="106" LastEditDate="2022-06-21T13:42:17.883" LastActivityDate="2022-06-21T13:42:17.883" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23941" PostTypeId="2" ParentId="23935" CreationDate="2022-06-20T14:12:14.070" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://www.cam.ac.uk/research/news/scientists-track-veil-of-toxic-metals-carried-in-kilaueas-gas-plumes-revealing-hidden-dangers-of&quot; rel=&quot;nofollow noreferrer&quot;&gt;This article&lt;/a&gt; states that volcanos can deposit heavy metals along with water vapor and sulfur compounds:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;When volcanoes erupt they exhale a cocktail of gases – mostly steam, carbon dioxide &amp;gt; and sulphur dioxide – laced with evaporated heavy metals, including lead and&#xA;arsenic. To the communities living alongside volcanoes, these gases are often a&#xA;considerable source of air pollution and the volatile metals they carry may have&#xA;long-lasting impacts on both health and environment.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It's probably best to secure them from being picked up by little hands as they tend to put items (especially their dirty fingers) back in their mouths.&lt;/p&gt;&#xA;" OwnerUserId="27050" LastActivityDate="2022-06-20T14:12:14.070" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23942" PostTypeId="1" AcceptedAnswerId="23944" CreationDate="2022-06-21T08:39:33.490" Score="6" ViewCount="213" Body="&lt;p&gt;I need elevation data with lat and long for a project worldwide. By intuition I would say that a GeoTiff would be suitable, e.g. the one from &lt;a href=&quot;https://asterweb.jpl.nasa.gov/gdem.asp&quot; rel=&quot;noreferrer&quot;&gt;https://asterweb.jpl.nasa.gov/gdem.asp&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Are there better ones, or does this one not contain any elevation data? Does anyone know where there are open source Geotiffs that are good? Or are there open source CSV files that contain the required information, or similar?&lt;/p&gt;&#xA;&lt;p&gt;ps. I only need the surface data from the mainland, not from the oceans.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-06-24T07:40:14.320" LastActivityDate="2022-06-24T07:40:14.320" Title="Geotiff for Elevation Data or NetCDF" Tags="|climate-models|mapping|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23943" PostTypeId="2" ParentId="23936" CreationDate="2022-06-21T09:23:05.867" Score="3" Body="&lt;p&gt;Smokey weather may be caused by normal atmospheric flows when smoke enters the air.&lt;/p&gt;&#xA;&lt;p&gt;In the last couple years around this time I have seen smoke arrive in the air over Chicago after being carried eastwards from wildfires in the Western United States. The air does not smell like smoke, but it becomes hazy as the particles absorb/diffuse light. It's especially noticeable when conditions are otherwise dry and cloudless.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2022-06-21T09:23:05.867" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23944" PostTypeId="2" ParentId="23942" CreationDate="2022-06-21T09:26:43.770" Score="7" Body="&lt;p&gt;'Better' will depend on your planned usage - any global product will have limitations in terms of overall accuracy and precision, and both the Aster photogrammetric data and the widely used &lt;a href=&quot;https://www2.jpl.nasa.gov/srtm/&quot; rel=&quot;noreferrer&quot;&gt;radar SRTM data&lt;/a&gt; don't have data at the poles. The &lt;a href=&quot;https://spacedata.copernicus.eu/web/cscda/dataset-details?articleId=394198&quot; rel=&quot;noreferrer&quot;&gt;Copernicus GLO-90 DEM&lt;/a&gt; is an alternative. At full resolution these are large datasets, so you may want to seek out a reduced resolution dataset, e.g. the &lt;a href=&quot;https://catalog.data.gov/dataset/srtm30-global-1-km-digital-elevation-model-dem-version-11-land-surface&quot; rel=&quot;noreferrer&quot;&gt;1km gridded NASA data&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2022-06-21T09:26:43.770" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23945" PostTypeId="2" ParentId="23837" CreationDate="2022-06-21T14:09:15.997" Score="1" Body="&lt;p&gt;I want to add to the initial answer from Oscar:&lt;/p&gt;&#xA;&lt;p&gt;But first, as a matter for geophysical terminology clarification, let's separate two very important concepts: &lt;em&gt;detection&lt;/em&gt; (i.e. &amp;quot;I see the top or the bottom or something in between the top and bottom, whatever that is...&amp;quot;) and &lt;em&gt;resolution&lt;/em&gt; (i.e. &amp;quot;I see the top &lt;em&gt;&lt;strong&gt;and&lt;/strong&gt;&lt;/em&gt; bottom, whatever that is...&amp;quot;).&lt;/p&gt;&#xA;&lt;p&gt;For the specific question, here's my take on it: there are &lt;em&gt;&lt;strong&gt;many, many&lt;/strong&gt;&lt;/em&gt; well-documented ways of doing this. Direct (well-logs, cores, etc.) and remote (seismic and potential fields). For &lt;strong&gt;seismic methods&lt;/strong&gt;, that's usually reflection or refraction. And, for &lt;strong&gt;potential fields&lt;/strong&gt;, that usually is electrical resistivity surveying (and then some kind of 2/3-D inversion) or GPR.&lt;/p&gt;&#xA;&lt;p&gt;As for sources, there's a lot of useful stuff &lt;a href=&quot;https://wiki.seg.org/wiki/Geophysical_tutorials&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2022-06-21T14:09:15.997" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23946" PostTypeId="1" AcceptedAnswerId="23971" CreationDate="2022-06-22T07:54:18.030" Score="6" ViewCount="61" Body="&lt;p&gt;I'm reading articles about climate models for possible exoplanets, and I'm confused as to what the &amp;quot;strength&amp;quot; of a Hadley or Ferrell cell refers to. Does it refer to wind speed? Wind force?&lt;/p&gt;&#xA;" OwnerUserId="26907" LastActivityDate="2022-06-30T00:36:23.317" Title="What does the &quot;strength&quot; of a circulation cell refer to?" Tags="|atmosphere|climate-models|atmospheric-circulation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23947" PostTypeId="1" AcceptedAnswerId="23949" CreationDate="2022-06-22T07:54:39.593" Score="3" ViewCount="581" Body="&lt;p&gt;Hi I need For each Lat and Long value also the Alt value! However, I am having problems extracting these values from a Geotiff and wonder if this data is publicly available in Excel or CSV file format? Unfortunately I have not found anything myself!&lt;/p&gt;&#xA;&lt;p&gt;my data: &lt;a href=&quot;https://wetransfer.com/downloads/8e5ba7aa4cd8c406068a60543b353b0420220622084939/d3c744&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://wetransfer.com/downloads/8e5ba7aa4cd8c406068a60543b353b0420220622084939/d3c744&lt;/a&gt;&#xA;For people who know Python:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import numpy as np&#xA;import matplotlib.pyplot as plt&#xA;from netCDF4 import Dataset&#xA;import pandas as pd&#xA;&#xA;data = Dataset(&amp;quot;C:/Users/Oliver Weisser/Desktop/Bachelor/Programm/Daten/Daten/ETOPO1_Bed_g_gdal.grd&amp;quot;,'r')&#xA;print(data.variables.keys())&#xA;&#xA;lon_range = data.variables['x_range'][:]&#xA;lat_range = data.variables['y_range'][:]&#xA;topo_range = data.variables['z_range'][:]&#xA;spacing = data.variables['spacing'][:]&#xA;dimension = data.variables['dimension'][:]&#xA;z = data.variables['z'][:]&#xA;lon_num =  dimension[0]&#xA;lat_num =  dimension[1]&#xA;&#xA;lon = np.linspace(lon_range[0],lon_range[1],dimension[0])&#xA;lat = np.linspace(lat_range[0],lat_range[1],dimension[1])&#xA;&#xA;topo = np.reshape(z, (lat_num, lon_num))&#xA;&#xA;&#xA;dfl = pd.DataFrame({&#xA;        'Latitude': lat.reshape(-1),&#xA;        'Longitude': lon.reshape(-1),&#xA;        'Altitude': topo.reshape(-1)&#xA;        })&#xA;print(dfl)&#xA;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/23904/etopo1-region-selection-in-python/23924#23924&quot;&gt;ETOPO1 region selection (in python)&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is the code I have written so far, maybe someone will find a bug there&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-06-22T11:26:15.423" LastActivityDate="2022-06-22T12:00:20.933" Title="World Elevation Data as CSV" Tags="|models|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23948" PostTypeId="1" CreationDate="2022-06-22T10:53:03.340" Score="1" ViewCount="57" Body="&lt;p&gt;In a book I read, I believe the author defined wind as the sum of &lt;em&gt;breezes&lt;/em&gt;, &lt;em&gt;weather&lt;/em&gt;, and &lt;em&gt;climate&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;breezes&lt;/strong&gt;: hyper-local disturbances, due to topology or uneven heating of surfaces&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;weather&lt;/strong&gt;: the movement of air due to regional atmospheric highs and lows&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;climate&lt;/strong&gt;: the steady state air movement linked to, e.g., latitude&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;em&gt;The sum of these three vector fields is the true wind at any given moment, at any given spot.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Two questions:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Is this definition correct?&lt;/li&gt;&#xA;&lt;li&gt;Is this definition in common use?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="23136" LastEditorUserId="23136" LastEditDate="2022-06-22T11:34:25.997" LastActivityDate="2022-06-22T11:34:25.997" Title="Is wind commonly formally defined as some combination of breezes, weather fronts, and climate?" Tags="|wind|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23949" PostTypeId="2" ParentId="23947" CreationDate="2022-06-22T12:00:20.933" Score="4" Body="&lt;p&gt;So I hope I finally understood what your problem really was and this gives you the height information at your specific lat lon values from your csv data.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import numpy as np&#xA;from netCDF4 import Dataset&#xA;import matplotlib.pyplot as plt&#xA;&#xA;csv_data = np.loadtxt('1994_12_O18grid.csv',skiprows=1,delimiter=',')&#xA;&#xA;num_el = csv_data[:,0]&#xA;lat = csv_data[:,1]&#xA;lon = csv_data[:,2]&#xA;value = csv_data[:,3]&#xA;&#xA;data = Dataset(&amp;quot;ETOPO1_Bed_g_gdal.grd&amp;quot;,'r')&#xA;lon_range = data.variables['x_range'][:]&#xA;lat_range = data.variables['y_range'][:]&#xA;topo_range = data.variables['z_range'][:]&#xA;spacing = data.variables['spacing'][:]&#xA;dimension = data.variables['dimension'][:]&#xA;z = data.variables['z'][:]&#xA;lon_num =  dimension[0]&#xA;lat_num =  dimension[1]&#xA;&#xA;etopo_lon = np.linspace(lon_range[0],lon_range[1],dimension[0])&#xA;etopo_lat = np.linspace(lat_range[0],lat_range[1],dimension[1])&#xA;topo = np.reshape(z, (lat_num, lon_num))&#xA;&#xA;height = np.empty_like(num_el)&#xA;for i in range(len(num_el)):  #in this loop we search for the height values for the specific lat and lon values from your csv&#xA;    desired_lat_idx = np.abs(etopo_lat - lat[i]).argmin()&#xA;    desired_lon_idx = np.abs(etopo_lon - lon[i]).argmin()&#xA;    height[i] = topo[desired_lat_idx,desired_lon_idx]&#xA;&#xA;plt.figure()&#xA;height[height&amp;lt;0]=0 # if you want to disregard values below 0&#xA;plt.imshow(np.reshape(height,(180,360))) # if the resolution of your csv data changes from 1 degree to something different you need to chance the values in the reshape. For simplicity I hardcoded the numbers.&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;The searching for the height levels is not that efficient but I didnt have the time to do a proper numpy style solution.&lt;/p&gt;&#xA;" OwnerUserId="26870" LastActivityDate="2022-06-22T12:00:20.933" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23951" PostTypeId="1" CreationDate="2022-06-23T13:37:46.810" Score="2" ViewCount="81" Body="&lt;p&gt;I am interested in geological maps for multiple African countries: Egypt, Sudan, and Ivory Coast. Is there any geoportal available for Africa, something similar to &lt;a href=&quot;https://www.geokniga.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;geokniga&lt;/a&gt; or &lt;a href=&quot;http://webmapget.vsegei.ru/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;vsegei&lt;/a&gt;, but for Arican countries? Or other free resources from where I could source these maps? &lt;br/&gt;&#xA;I did find a paid resource, &lt;a href=&quot;https://shop.geospatial.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;East View Geospatial&lt;/a&gt;, but I would very much prefer a free option if one exists. &lt;br/&gt;&#xA;For Egypt and for Sudan(partially) I found some free resources, but I decided to ask here as well, maybe the community here knows some other portals.&lt;/p&gt;&#xA;" OwnerUserId="27064" LastActivityDate="2022-06-24T08:43:36.740" Title="Where can I find geological maps for countries from Africa?" Tags="|geology|mapping|mining|resources|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23952" PostTypeId="2" ParentId="23951" CreationDate="2022-06-24T08:43:36.740" Score="4" Body="&lt;p&gt;You may find some of the maps you seek on the &lt;a href=&quot;https://www.onegeology.org/portal/home.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;OneGeology&lt;/a&gt; portal, which gives access to both regional mapping and maps uploaded by national geological surveys. You could also review the data available on the &lt;a href=&quot;https://www.bgs.ac.uk/geology-projects/africa-groundwater-atlas/&quot; rel=&quot;nofollow noreferrer&quot;&gt;African Groundwater Atlas&lt;/a&gt; page, which has maps and links to hydrogeological (and geological) resources, although the amount of data may vary by country, depending on how much data has been placed in the public domain.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2022-06-24T08:43:36.740" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23953" PostTypeId="2" ParentId="16000" CreationDate="2022-06-25T02:23:32.553" Score="0" Body="&lt;p&gt;The closest point on the Earth to the Sun needs be a subsolar point on a monumental tropical summit, on January 4th during a &lt;a href=&quot;https://www.timeanddate.com/astronomy/moon/micro-moon.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;micromoon&lt;/a&gt;, when the the Moon is maximally out, and the Earth is maximally inside our shared Earth/Moon orbit.&lt;/p&gt;&#xA;" OwnerUserId="27074" LastEditorUserId="6298" LastEditDate="2022-06-25T21:28:54.233" LastActivityDate="2022-06-25T21:28:54.233" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23954" PostTypeId="2" ParentId="22728" CreationDate="2022-06-25T07:01:38.390" Score="-3" Body="&lt;p&gt;I would like to give some food for thought here. I live in Louisiana where fracking is causing cracking deep below the surface of the earth. If you look at a map of fracking locations in the US you will be shocked at the number or amount of red dots that pinpoint fracking locations. One state is almost completely filled with red dots. There are hundreds and hundreds of thousands fracking locations from north to south part of the central US. While fracking miles below the earths surface then horizontally for over 5 miles in some cases fracking technique uses 6 explosions of like dynamite every 1’ of cutting into the rock. Yes, 6 dynamite explosions every 1’ in order to break the rock for the drill bits to drill through. Now use that calculation 6 explosions per foot along with the depths of the explosions times the number of the hundreds of thousands of fracking locations to determine how much the rock miles below ground that is closer to the earths core has been loosened. The broken and cracked rock below the earths surface that is an insulating factor that helps protect the earths surface has been broken and cracked in hundreds of thousands of locations due to fracking. The insulating rock below, the insulation, that protects the earths surface is being destroyed and weakened therefore heat from the earths core will find the path of least resistance and that my friends is through the broken and cracked rock caused by fracking miles below the earths surface.&lt;/p&gt;&#xA;&lt;p&gt;Mixed toxic chemicals and fluids are made and concocted by non scientist that are used in fracking to cool down the fracking drill bits. It is very hot below where fracking takes place and the toxic chemicals being used may also be a contributing factor to the earths surface heating up.&lt;/p&gt;&#xA;" OwnerUserId="27075" LastActivityDate="2022-06-25T07:01:38.390" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23955" PostTypeId="1" AcceptedAnswerId="23956" CreationDate="2022-06-25T19:26:08.780" Score="4" ViewCount="369" Body="&lt;p&gt;The Keeling curve reports CO&lt;sub&gt;2&lt;/sub&gt; in units of μmol/mol, but people's (and country's) emissions are generally reported in kilograms or tons of CO&lt;sub&gt;2&lt;/sub&gt;. I would like to convert μmol/mol of CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere to mass fraction of CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere using an accurate, well-established, and scientifically accepted method to ensure that my calculations are reproducible by others. What is the preferred way to do this?&lt;/p&gt;&#xA;" OwnerUserId="27098" LastEditorUserId="2470" LastEditDate="2022-06-25T23:15:27.890" LastActivityDate="2022-06-25T23:22:04.273" Title="How do you convert the μmol/mol units for atmospheric CO2 into CO2 mass fraction?" Tags="|atmosphere|climatology|carbon|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23956" PostTypeId="2" ParentId="23955" CreationDate="2022-06-25T23:22:04.273" Score="4" Body="&lt;p&gt;TL;DR: Multiply &lt;span class=&quot;math-container&quot;&gt;$\ce{CO_2}$&lt;/span&gt; expressed in μmol/mol by 1.52 the μg/g equivalent.&lt;/p&gt;&#xA;&lt;p&gt;Details: The molecular mass of &lt;span class=&quot;math-container&quot;&gt;$\ce{CO_2}$&lt;/span&gt; is 44.01 g/mol. The standard molecular mass of dry air is 28.9647 g/mol. Multiplying &lt;span class=&quot;math-container&quot;&gt;$\ce{CO_2}$&lt;/span&gt; expressed in μmol/mol by 44.01/28.9647=1.5194 comes rather close. A tricky detail is that some of that standard molecular mass of dry air includes a small contribution from &lt;span class=&quot;math-container&quot;&gt;$\ce{CO_2}$&lt;/span&gt;. After accounting for this I get a value close a bit over 1.5196. Rounding either value to three significant digits results in a conversion factor of 1.52.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-06-25T23:22:04.273" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23958" PostTypeId="1" CreationDate="2022-06-26T14:41:06.987" Score="4" ViewCount="25" Body="&lt;p&gt;The Iribarren number (slope ratio/√wave steepness) gives appearance of breaking waves. If the number is low, a spilling breaker occurs. If it is moderate, a spectacular plunger occurs. If it is large, a partially breaking or non breaking wave occurs.&lt;/p&gt;&#xA;&lt;p&gt;But this number was developed for &amp;quot;normal&amp;quot; waves with steepness of, what, a few dozenths? Tsunamis can have steepness as low as in the thousandths. Does this criteria still accurately predict the appearance of a breaking tsunami?&lt;/p&gt;&#xA;" OwnerUserId="26988" LastActivityDate="2022-06-26T14:41:06.987" Title="Does the Iribarren criteria apply for tsunamis?" Tags="|tsunami|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23959" PostTypeId="1" CreationDate="2022-06-26T17:40:42.857" Score="5" ViewCount="1043" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/28kIu.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/28kIu.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;Can anyone explain these strange rays?&#xA;They seem to be pulsing in roughly the same location when you watch the radar and are always in the same circle pattern.&#xA;Thanks for your input!&lt;/p&gt;&#xA;" OwnerUserId="27103" LastEditorUserId="18088" LastEditDate="2022-06-27T15:34:10.010" LastActivityDate="2022-06-27T15:34:10.010" Title="Strange Circular Rays showing up on radar" Tags="|atmosphere|earth-observation|radar|" AnswerCount="1" CommentCount="2" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23960" PostTypeId="2" ParentId="23959" CreationDate="2022-06-26T22:56:00.947" Score="6" Body="&lt;p&gt;These appear to bursts of electromagnetic interferences (EMI).  The rays are all centered on the location of the weather radars.  As the weather radars rotate and receive interference they interpret it as a weather return in the direction they are pointing in at the time the interference signal is received.  As these radars have no additional means of determining the direction of arrival of the signals we see these &amp;quot;spokes.&amp;quot;  The sources of this interference, which is EM radiation at the same wavelength of the radar, is typically from spillover from telecommunication equipment or other radars using in similar wavelengths.&lt;/p&gt;&#xA;&lt;p&gt;Similar patterns can be seen is this image:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/er9nI.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/er9nI.png&quot; alt=&quot;Uncorrected horizontal reflectivity Zh acquired by Bric della Croce radar in 2010&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This figure is from &lt;em&gt;&lt;a href=&quot;https://www.mdpi.com/2076-3298/6/12/126/htm&quot; rel=&quot;noreferrer&quot;&gt;Survey on Electromagnetic Interference in Weather Radars in Northwestern Italy&lt;/a&gt;&lt;/em&gt;,a paper studying the impact of interference on weather radar.&lt;/p&gt;&#xA;" OwnerUserId="18088" LastEditorUserId="6298" LastEditDate="2022-06-27T01:11:17.083" LastActivityDate="2022-06-27T01:11:17.083" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23961" PostTypeId="1" AcceptedAnswerId="23968" CreationDate="2022-06-27T01:41:12.257" Score="5" ViewCount="504" Body="&lt;p&gt;Looking at &lt;a href=&quot;https://en.wikipedia.org/wiki/Absorption_band&quot; rel=&quot;noreferrer&quot;&gt;the Wikipedia page for absorption bands&lt;/a&gt;, it seems to me that there's a sizable window - i.e. a &lt;a href=&quot;https://en.wikipedia.org/wiki/Maxima_and_minima&quot; rel=&quot;noreferrer&quot;&gt;local minimum&lt;/a&gt; - in the graph for &lt;a href=&quot;https://en.wikipedia.org/wiki/Electromagnetic_radiation&quot; rel=&quot;noreferrer&quot;&gt;electromagnetic radiation&lt;/a&gt; absorption, as per the edited image below.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Water_vapor&quot; rel=&quot;noreferrer&quot;&gt;Water vapor&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Oxygen&quot; rel=&quot;noreferrer&quot;&gt;oxygen&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Ozone&quot; rel=&quot;noreferrer&quot;&gt;ozone&lt;/a&gt;, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Methane&quot; rel=&quot;noreferrer&quot;&gt;methane&lt;/a&gt; appear to be entirely transparent to radiation of 4 μm wavelength, &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_dioxide&quot; rel=&quot;noreferrer&quot;&gt;carbon dioxide&lt;/a&gt; only appears to start absorbing it &lt;em&gt;after&lt;/em&gt; that point, and even &lt;a href=&quot;https://en.wikipedia.org/wiki/Nitrous_oxide&quot; rel=&quot;noreferrer&quot;&gt;nitrous oxide&lt;/a&gt; has a window there. Moreover, &lt;a href=&quot;https://en.wikipedia.org/wiki/Rayleigh_scattering&quot; rel=&quot;noreferrer&quot;&gt;Rayleigh scattering&lt;/a&gt; is also minimal there.&lt;/p&gt;&#xA;&lt;p&gt;On top of &lt;em&gt;that&lt;/em&gt;, &lt;a href=&quot;https://earthscience.stackexchange.com/a/13621/23134&quot;&gt;this Earth Science Stack Exchange answer&lt;/a&gt; by &lt;a href=&quot;https://earthscience.stackexchange.com/users/11908/camilo-rada&quot;&gt;Camilo Rada&lt;/a&gt; and &lt;a href=&quot;https://webbook.nist.gov/cgi/cbook.cgi?ID=C7446095&amp;amp;Type=IR-SPEC&amp;amp;Index=0&quot; rel=&quot;noreferrer&quot;&gt;its source&lt;/a&gt; show minimal (sub-0.5%) absorbance of sulfur dioxide at that wavelength.&lt;/p&gt;&#xA;&lt;p&gt;Why is this? It seems like a rather odd coincidence for so many things to be transparent to 4 μm (a specific wavelength of &lt;a href=&quot;https://en.wikipedia.org/wiki/Infrared#Regions_within_the_infrared&quot; rel=&quot;noreferrer&quot;&gt;mid-wavelength infrared&lt;/a&gt;) EM radiation.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jOhUm.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jOhUm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="23134" LastActivityDate="2022-06-28T14:25:27.307" Title="Why is there a window in the absorption spectrum of Earth's atmosphere at a wavelength of 4 μm?" Tags="|atmosphere|atmospheric-chemistry|atmospheric-radiation|electromagnetism|" AnswerCount="1" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="23963" PostTypeId="1" AcceptedAnswerId="23967" CreationDate="2022-06-27T09:45:11.280" Score="1" ViewCount="72" Body="&lt;p&gt;I would like to show the change in temperatures since 1960 until today. I have thought about creating two time blocks, e.g. from 1960-1970 and from 2010-2020! Then I want to average the data of these two time blocks (i.e. the data from 1960-1970 and from 2010-2020) and then calculate the difference between the two time blocks. Now I wonder if there are rules in the geosciences about how large the time periods should be, because I simply assumed the 10 years. The question for me is what period can be assumed as the minimum to prevent extreme years (either extremely hot or extremely cold) from having a major influence?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2022-06-28T09:15:17.930" Title="Milancovich analysis" Tags="|climate-change|models|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23964" PostTypeId="1" AcceptedAnswerId="23970" CreationDate="2022-06-27T16:14:52.153" Score="2" ViewCount="282" Body="&lt;p&gt;The game Worldle (&lt;a href=&quot;https://worldle.teuteuf.fr/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://worldle.teuteuf.fr/&lt;/a&gt;) is related to the recent craze in online once-a-day puzzles like &lt;a href=&quot;https://www.nytimes.com/games/wordle/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wordle&lt;/a&gt;. You are shown the outline of a country and get six guesses. For each wrong guess, you are told the distance and direction to go to get to the right answer.&lt;/p&gt;&#xA;&lt;p&gt;It is of course fun for lovers of geography. But it also presents an opportunity to attune to the relationship between coastline shape (or border shapes in general) and geographic region or other country characteristics.&lt;/p&gt;&#xA;&lt;p&gt;For example, when I saw the &lt;a href=&quot;https://web.archive.org/web/20220226181500/https://worldle.teuteuf.fr/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Worldle for this country&lt;/a&gt; last February 26, I noticed the jagged coastline, and surmised that it might be of volcanic origin - a big clue given some general knowledge of the locations of the plates. (I wanted an illustrative example, but for those who want to play it from the link above, I'll refrain from spoiling it further by giving the full answer.)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sT3ha.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sT3ha.png&quot; alt=&quot;country outline for 2022-02-26 Worldle&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I imagine that there may be other hints that can be derived from the coastline shapes or numbers of islands that would be correlated with the differences between islands in different regions of the earth. For example, if I see an &lt;a href=&quot;https://en.wikipedia.org/wiki/Atoll&quot; rel=&quot;nofollow noreferrer&quot;&gt;atoll&lt;/a&gt;-like shape, I dare say it is more likely to be a Pacific island than something in the Caribbean, and having a closer first guess helps.&lt;/p&gt;&#xA;&lt;p&gt;I'm guessing generic geographic knowledge can also be helpful for internal borders which are related to rivers and mountains, but I don't know much about general shape-related differences between such things in different regions.&lt;/p&gt;&#xA;&lt;p&gt;To pose my question broadly: what other geographic and earth-science knowledge can you explain here or provide references to which would be both fun to study, and provide helpful background for playing Worldle?&lt;/p&gt;&#xA;" OwnerUserId="14385" LastActivityDate="2022-06-29T08:14:51.960" Title="Guessing region of the world from coastline / border shape: geographic insights for Worldle game" Tags="|geography|mountains|coastal|islands|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23965" PostTypeId="1" CreationDate="2022-06-27T16:43:17.707" Score="3" ViewCount="239" Body="&lt;p&gt;I'm part of an organization maintaning a large network of weather stations (~3000 stations) over a European country.&#xA;Besides storing data measured from the stations into a database, we also produce maps of interpolated values over a 2.5 km regular grid. At the moment we're using the Natural Neighbour algorithm from pyngl (&lt;code&gt;natgrid&lt;/code&gt;, &lt;a href=&quot;https://www.pyngl.ucar.edu/Functions/Ngl.natgrid.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.pyngl.ucar.edu/Functions/Ngl.natgrid.shtml&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;While most of the variables are directly interpolated on the grid, the temperature is always scaled with the height in order to obtain a better representation of the gradient over mountainous regions (see an example image)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XnkvF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XnkvF.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I've been trying to find a better way to interpolate the data without success. My ideal algorithm should be able to&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;take scattered data (as temperature, rain, humidity...) as input: data is varying between 1000 and 5000 points depending on the time of the day&lt;/li&gt;&#xA;&lt;li&gt;add external parameters such as altitude or latitude to improve the interpolation of data over area where station data is missing (like mountainous regions), similar to what done with kriging drifts. Ideally we could even use radar data to correct precipitation estimates. This should be tuned automatically by the algorithm itself without the need to intervene&lt;/li&gt;&#xA;&lt;li&gt;be fast (less than 10 seconds to interpolate all data)&lt;/li&gt;&#xA;&lt;li&gt;ideally use a machine learning model trained on the entire archive of the data to improve the interpolation? (this is optional)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I've been trying with RBF interpolation, all the methods from &lt;code&gt;metpy&lt;/code&gt; (&lt;a href=&quot;https://unidata.github.io/MetPy/latest/examples/gridding/Point_Interpolation.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://unidata.github.io/MetPy/latest/examples/gridding/Point_Interpolation.html&lt;/a&gt;), and even &lt;code&gt;pykrige&lt;/code&gt; with Ordinary Kriging or Regression Kriging with a Random Forest regressor. Somehow I could not find a method that satisfies all the previous conditions: &lt;code&gt;natgrid&lt;/code&gt; still seems to be the fastest and most accurate algorithm.&lt;/p&gt;&#xA;&lt;p&gt;Can someone point me in the right direction?&lt;/p&gt;&#xA;" OwnerUserId="27107" LastActivityDate="2022-06-27T16:43:17.707" Title="Best method for weather station data interpolation with external parameters" Tags="|meteorology|temperature|precipitation|interpolation|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="23966" PostTypeId="1" CreationDate="2022-06-28T08:17:42.780" Score="1" ViewCount="38" Body="&lt;p&gt;Hi I was wondering if there are any good open Access models of the oceans from the 1890's to, lets say 2100! I have already found the site but I am looking for more alternatives:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://esgf-node.llnl.gov/search/cmip6/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://esgf-node.llnl.gov/search/cmip6/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I have a preference for Python but R is also Ok.&lt;/p&gt;&#xA;&lt;p&gt;If there is no good model, are there interactive websites or well known papers? I found: &lt;a href=&quot;https://journals.ametsoc.org/view/journals/clim/20/21/2007jcli1714.1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://journals.ametsoc.org/view/journals/clim/20/21/2007jcli1714.1.xml&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;or something similar to: &lt;a href=&quot;https://sites.ecmwf.int/era/40-atlas/docs/section_B/parameter_emp.html#&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://sites.ecmwf.int/era/40-atlas/docs/section_B/parameter_emp.html#&lt;/a&gt; (but it should show the change of evaporation)&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="2470" LastEditDate="2022-06-28T17:34:24.507" LastActivityDate="2022-06-28T17:34:24.507" Title="Change in evaporation in the North Atlantic since 1890" Tags="|climate-change|python|evaporation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23967" PostTypeId="2" ParentId="23963" CreationDate="2022-06-28T09:15:17.930" Score="6" Body="&lt;p&gt;The most common period to use is 30-years, which comes from the idea of &lt;a href=&quot;https://en.wikipedia.org/wiki/Climatological_normal&quot; rel=&quot;noreferrer&quot;&gt;climate normals&lt;/a&gt; used in NWP.  Using only 10 years even global mean temperature will see the influence of a single large El Nino or prolonged La Nina events, which probably isn't what you're after.  If you were writing a paper that used 30-years means, the reviewer probably wouldn't question it; if you used 20-year means they might ask you to justify it; if you used 10-year means you'd probably be criticized for it.&lt;/p&gt;&#xA;&lt;p&gt;Regardless of what period you pick, it's always a good idea to also calculate confidence intervals for your means, which can give you a sanity check on whether differences between periods are really notable.  That's sort of one step short of doing formal statistical hypothesis testing.&lt;/p&gt;&#xA;&lt;p&gt;From the IPCC AR6 glossary, for reference:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;em&gt;Climate&lt;/em&gt;: Climate in a narrow sense is usually defined as the average weather, or more rigorously, as the statistical description in terms of the mean and variability of relevant quantities over a period of time ranging from months to thousands or millions of years. The classical period for averaging these variables is &lt;strong&gt;30 years&lt;/strong&gt;, as defined by the World Meteorological Organization (WMO). The relevant quantities are most often surface variables such as temperature, precipitation and wind. Climate in a wider sense is the state, including a statistical description, of the climate system.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;em&gt;Global warming&lt;/em&gt;: Global warming refers to the increase in global surface temperature relative to a baseline reference period, averaging over a period sufficient to remove interannual variations (e.g., &lt;strong&gt;20 or 30 years&lt;/strong&gt;). A common choice for the baseline is 1850-1900 (the earliest period of reliable observations with sufficient geographic coverage), with more modern baselines used depending upon the application.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="106" LastActivityDate="2022-06-28T09:15:17.930" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23968" PostTypeId="2" ParentId="23961" CreationDate="2022-06-28T14:25:27.307" Score="5" Body="&lt;p&gt;There is simply no strong enough absorption of any of the greenhouse gases at this wavelength. However this does not mean that there is none.&lt;/p&gt;&#xA;&lt;p&gt;Remember that what you are seeing here is the transmission function, and plotted on a linear scale, to add to it. The transmission function per wavelength at a certain atmospheric altitude z is defined as &lt;span class=&quot;math-container&quot;&gt;$T = I(z)/I_0 = e^{-\tau(z)}$&lt;/span&gt;, where the optical depth &lt;span class=&quot;math-container&quot;&gt;$\tau$&lt;/span&gt; is the line-of-sight integral over all species' opacities times densities along a path, i.e. &lt;span class=&quot;math-container&quot;&gt;$\tau(z)=\int_z^\infty dz\; \sum_{\rm species} \rho_s(z) \kappa_{s}(z)$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$\rho(z)$&lt;/span&gt; is the density of a species &lt;span class=&quot;math-container&quot;&gt;$s$&lt;/span&gt; at a given altitude, and &lt;span class=&quot;math-container&quot;&gt;$\kappa_{s}$&lt;/span&gt;.&lt;br /&gt;&#xA;A quick look at the opacity of water at 1 bar and 300K in logscale (taken from the &lt;a href=&quot;https://dace.unige.ch/opacity/&quot; rel=&quot;noreferrer&quot;&gt;DACE opacity database&lt;/a&gt;) shows that there is just a significant drop in the regular molecular wavebands at this wavelength, and nothing else. Same with the other species.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/06vz0.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/06vz0.png&quot; alt=&quot;Opacity function of water at 1 bar and 300K&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So the fact that just at 4 micron there seems to be a suspicious drop is because our atmospheric column depth integral over &lt;span class=&quot;math-container&quot;&gt;$\rho(z)$&lt;/span&gt; at this wavelength just gives a small, but nonzero value for &lt;span class=&quot;math-container&quot;&gt;$\tau(z)$&lt;/span&gt;. If the transmission plot were logarithmic, you'd see this nonzero value.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, to try and make sense of&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Why is this? It seems like a rather odd coincidence for so many things to be transparent to 4 μm (a specific wavelength of mid-wavelength infrared) EM radiation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Just think of molecular opacities being periodic signals in wavelength space. If you stack enough periods, you will always find a minimum somewhere, by superposition. For the few ingredients you mentioned, this minimum just happens to be at 4&lt;span class=&quot;math-container&quot;&gt;$\mu$&lt;/span&gt;m.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2022-06-28T14:25:27.307" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23969" PostTypeId="1" CreationDate="2022-06-28T22:44:21.387" Score="2" ViewCount="38" Body="&lt;p&gt;Imagine the Earth contains 50% the water it currently contains. The oceans are still located in the same place, but they are much shallower. How would this affect the climate and the climate stability of the planet?&lt;/p&gt;&#xA;" OwnerUserId="26907" LastActivityDate="2022-06-28T22:44:21.387" Title="What would the climate and greenhouse effects be if the oceans contained half as much water?" Tags="|climate|oceanography|planetary-science|hypothetical|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23970" PostTypeId="2" ParentId="23964" CreationDate="2022-06-29T08:14:51.960" Score="5" Body="&lt;p&gt;I can think of at least two features that could help identifying a country: one geographical, and one geological.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Geographical feature: long, straight borders&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;This type of border has usually been drawn by colonial empires, and is found mostly in Africa, Middle East, Central Asia, and the Americas. Europe has very few of those (the Poland&lt;span class=&quot;math-container&quot;&gt;$-$&lt;/span&gt;Russia border being an exception). So if you see a long, straight border, you can almost be sure that it is not a European country.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Geological feature: jagged coastline&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;As shown in your example, some coastlines are really jagged. This is not due to some volcanic origin, but rather to the presence of &lt;a href=&quot;https://en.wikipedia.org/wiki/Fjord&quot; rel=&quot;noreferrer&quot;&gt;fjords&lt;/a&gt;, carved during the last glacial periods. Fjords are found at rather high latitudes, say, from about 50°N (there are fjords as &amp;quot;low&amp;quot; as Vancouver for instance), and from about 45°S (Chile, New Zealand). So, if you see this kind of coastline, you can definitely rule out tropical countries.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2022-06-29T08:14:51.960" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23971" PostTypeId="2" ParentId="23946" CreationDate="2022-06-29T08:36:22.473" Score="2" Body="&lt;p&gt;If I recall correctly from my bachelor lectures the strength of the Hadley or Ferrell cells are often described in terms of kg/s (or sverdrup, so 10&lt;sup&gt;9&lt;/sup&gt; kg/s), so i.e. mass flow of air.&lt;/p&gt;&#xA;&lt;p&gt;I am not sure if this is also used for exoplanets but it is used for the Earth.&lt;/p&gt;&#xA;&lt;p&gt;Source:&#xA;Fig. 7.19 on page 159 in &lt;a href=&quot;https://archive.org/details/peixoto-j.-p.-oort-a.-h.-physics-of-climate-1992/page/159/mode/2up&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://archive.org/details/peixoto-j.-p.-oort-a.-h.-physics-of-climate-1992/page/159/mode/2up&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26870" LastEditorUserId="2470" LastEditDate="2022-06-30T00:36:23.317" LastActivityDate="2022-06-30T00:36:23.317" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23972" PostTypeId="1" AcceptedAnswerId="23973" CreationDate="2022-06-29T09:47:32.890" Score="3" ViewCount="494" Body="&lt;p&gt;I'm currently wondering at what latitudes the precipitation water for Europe evaporates. For some reason I can hardly find any data on where the source of the vapour can be, which is then transported to Europe by advection with the westerly winds. Do you know any reliable sources or, even better, online models?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="6467" LastEditDate="2022-07-03T22:36:08.443" LastActivityDate="2022-07-03T22:36:08.443" Title="At what latitudes does the precipitation water for Europe evaporate?" Tags="|meteorology|precipitation|evaporation|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23973" PostTypeId="2" ParentId="23972" CreationDate="2022-06-29T16:31:15.473" Score="6" Body="&lt;p&gt;A challenge is going to be &amp;quot;which moisture is from where&amp;quot;.  Because the atmosphere doesn't ever completely empty of moisture, for any given precipitation, which water molecules were from which spot?&lt;/p&gt;&#xA;&lt;p&gt;But a satellite loop of precipitable water (the amount of water vapor in the tropospheric column) like &lt;a href=&quot;http://tropic.ssec.wisc.edu/real-time/mtpw2/product.php?color_type=tpw_nrl_colors&amp;amp;prod=global2&amp;amp;timespan=120hrs&amp;amp;anim=html5&quot; rel=&quot;noreferrer&quot;&gt;the MIMIC-TPW2 one from CIMMS-Wisconsin should help to shed light on your question&lt;/a&gt;.  Basically looking at the animation the lion's share of the moisture making it to Europe looks to be a mix of nearer northern Atlantic moisture -- particularly from the warmer Gulf Stream -- and then additional wider-scale evaporation nearer the ITCZ closer to the Equator in the Atlantic plus sub-basins like the Caribbean and Gulf of Mexico.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WTcmO.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WTcmO.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Perhaps a bit more is from more local areas when winds are reduced, and a bit more distant during cooler parts of the year when the jet stream is more active.  But I am confident that overall meteorologically these source areas would be rather consistently dominant throughout the year, as hinted at in this image of annual oceanic latent heat flux shows:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HYnTD.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HYnTD.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;sub&gt;&lt;sup&gt;(Found on &lt;a href=&quot;https://www.weather.gov/jetstream/whatacycle_max&quot; rel=&quot;noreferrer&quot;&gt;NOAA page about Jet Stream&lt;/a&gt;, indicated as from &lt;a href=&quot;https://oaflux.whoi.edu&quot; rel=&quot;noreferrer&quot;&gt;Wood's Hole OA Flux Project&lt;/a&gt;)&lt;/sup&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;That image, plus a close look at the animation, both seem to hint that the greatest percentage of your moisture tends to come from latitudes more like 30 north.  I might have thought it was more equally balanced with the deeper tropics.  Either way it's going to be the region roughly between the Equator and about 40 North where the vast majority of your moisture comes from, as that's where &lt;a href=&quot;https://www.nhc.noaa.gov/tafb/sst_loop/14_atl.png&quot; rel=&quot;noreferrer&quot;&gt;SSTs are much warmer&lt;/a&gt;... with the moisture carrying capacity of air &lt;a href=&quot;https://www.engineeringtoolbox.com/maximum-moisture-content-air-d_1403.html&quot; rel=&quot;noreferrer&quot;&gt;almost doubling&lt;/a&gt; between 20°C and 30°C (and again between 10°C and 20°C), meaning that SSTs and air (low) temperatures nearer 25-30°C bring much more significant amounts of moisture.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2022-06-29T16:31:15.473" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="23974" PostTypeId="2" ParentId="23447" CreationDate="2022-06-29T18:17:38.767" Score="-1" Body="&lt;p&gt;I see A LOT of misconceptions have been posted here about Geothermal energy.&lt;/p&gt;&#xA;&lt;p&gt;I will try to address most of them and hopefully people might take this updated data on Geothermal more seriously.&lt;/p&gt;&#xA;&lt;p&gt;First off, Geothermal is NOT constricted to only a few regions when it comes to electricity production. It can be accessed in the oceans fairly easily and literally anywhere else if we dig deep enough (and with lots of less effort with preexisting geothermal wells, etc.) :&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.geothermal-energy.org/pdf/IGAstandard/WGC/2015/37011.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.geothermal-energy.org/pdf/IGAstandard/WGC/2015/37011.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Heating and cooling (which accounts for about 40% of humanity's energy budget), is pretty much accessible in the form of Geothermal across the globe:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://education.nationalgeographic.org/resource/geothermal-energy/#:%7E:text=Almost%20anywhere%20in%20the%20world,C%20(302%C2%B0%20F)&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://education.nationalgeographic.org/resource/geothermal-energy/#:~:text=Almost%20anywhere%20in%20the%20world,C%20(302%C2%B0%20F)&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;There are a lot of volcanoes (inactive and active) across the globe that can be used for Geothermal power generation.&lt;/p&gt;&#xA;&lt;p&gt;The Yellowstone super volcano can basically power the entire globe twice over:&#xA;&lt;a href=&quot;https://www.forbes.com/sites/robinandrews/2017/09/29/yellowstone-supervolcano-could-power-the-entire-planet-twice-over/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.forbes.com/sites/robinandrews/2017/09/29/yellowstone-supervolcano-could-power-the-entire-planet-twice-over/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Also, according to MIT study from 2006, it was concluded that the Earth has 13000 zettajoules of Geothermal energy available (this was before newer studies determined that the core is actually HOTTER) and that with the technology available at the time (2006), we could easily extract 200 zettajoules of power (human civilization was using at the time 0.5 zettajoules per year... and accounting for 1 third of humanity that doesn't have access to electricity, this number would have to rise to 0.65 zettajoules - and if we take into account that its been 16 years since then and overall energy consumption increased by roughly 55%, the total amount of zettajoules humanity would be using in the world today could be estimated at approximately 1 zettajoules per year (also including one third of humanity that does not have access to electricity – so 1 zettajoules per year would be a scenario where ENTIRE humanity has access to electricity).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://energy.mit.edu/wp-content/uploads/2006/11/MITEI-The-Future-of-Geothermal-Energy.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://energy.mit.edu/wp-content/uploads/2006/11/MITEI-The-Future-of-Geothermal-Energy.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So, we already had the ability to tap into 200 years worth of base load geothermal power since 2006... and eventually into 2000 years worth of power with improved technologies.&lt;/p&gt;&#xA;&lt;p&gt;Now, what most people here ignore is that Geothermal can in fact be accessed anywhere in the globe if we dig deep enough (which, lets be fair, is not too much of a hassle with modern technology because if the oil/gas companies could dig kilometers deep into the ground for oil and gas 100 years ago, then doing the same, or a little deeper for Geothermal would hardly be the problem).&lt;/p&gt;&#xA;&lt;p&gt;Furthermore, Geothermal has lower operational costs than any other energy source on the planet ranging between \$19 and \$36 per MWh (especially compared to Nuclear which costs between \$112 and &amp;amp; \$189 per MWh), pays for itself ENTIRELY (yes, this includes cost of digging, etc.) in 3-7 years, is far more reliable, can last over 100 years per power plant if adequately maintained,  has no running fuel costs, is cheaper to run and uses smaller amount of land area compared to most other energy sources:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.energy.gov/eere/geothermal/geothermal-faqs&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.energy.gov/eere/geothermal/geothermal-faqs&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.energy.gov/eere/geothermal/geothermal-power-plants-minimizing-land-use-and-impact#:%7E:text=An%20entire%20geothermal%20field%20uses,acreages%20for%20mining%20their%20fuel&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.energy.gov/eere/geothermal/geothermal-power-plants-minimizing-land-use-and-impact#:~:text=An%20entire%20geothermal%20field%20uses,acreages%20for%20mining%20their%20fuel&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The first Geothermal power plant ever constructed in Italy in 1913 is still in operation today with vastly expanded power generation:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.power-technology.com/analysis/oldest-geothermal-plant-larderello/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.power-technology.com/analysis/oldest-geothermal-plant-larderello/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Adding to this, all oil and gas wells (along with the personnel and their skills) throughout the globe can be fairly easily transferred/converted into Geothermal for both electricity and heat production for HALF as much money/cost than it would take to decommission them.&lt;/p&gt;&#xA;&lt;p&gt;A company in Australia is also looking to use its technology to convert coal fired power plants into Geothermal power stations too.&#xA;Geothermal brines are also rich in various minerals such as Lithium. In fact, in the USA, a mere handful of Geothermal power plants can supply the entire nation with more lithium it could ever hope to use (same for the Geothermal power plant in Cornwall).&lt;/p&gt;&#xA;&lt;p&gt;More info can be found here on all these points I mentioned:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.offshore-mag.com/pipelines/article/16762144/geothermal-power-an-alternate-role-for-redundant-north-sea-platforms&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.offshore-mag.com/pipelines/article/16762144/geothermal-power-an-alternate-role-for-redundant-north-sea-platforms&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.pressandjournal.co.uk/fp/business/local/3028309/plan-to-repurpose-rigs-for-geothermal-energy/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.pressandjournal.co.uk/fp/business/local/3028309/plan-to-repurpose-rigs-for-geothermal-energy/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.energy.gov/eere/articles/doe-awards-84-million-accessing-geothermal-potential-abandoned-oil-and-gas-wells&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.energy.gov/eere/articles/doe-awards-84-million-accessing-geothermal-potential-abandoned-oil-and-gas-wells&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://techxplore.com/news/2022-02-quaise-energy-power-geothermal-drilling.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://techxplore.com/news/2022-02-quaise-energy-power-geothermal-drilling.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.boisestate.edu/news/2022/03/21/how-a-few-geothermal-plants-could-solve-americas-lithium-supply-crunch-and-boost-the-ev-battery-industry/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.boisestate.edu/news/2022/03/21/how-a-few-geothermal-plants-could-solve-americas-lithium-supply-crunch-and-boost-the-ev-battery-industry/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.euractiv.com/section/energy/news/game-changer-for-geothermal-energy-as-uk-plant-unlocks-vast-supply-of-lithium/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.euractiv.com/section/energy/news/game-changer-for-geothermal-energy-as-uk-plant-unlocks-vast-supply-of-lithium/&lt;/a&gt;&#xA;People seem to be generally operating on outdated information.&lt;/p&gt;&#xA;&lt;p&gt;Here's an additional article on Supercritical Geothermal and how it could power quite literally EVERYTHING and the main reason its development progressed so slowly (hint: lack of funding, not technology or accessibility) :&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://spheresofinfluence.ca/geothermal-energy-can-the-forgotten-renewable-make-its-mark/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://spheresofinfluence.ca/geothermal-energy-can-the-forgotten-renewable-make-its-mark/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.energymonitor.ai/tech/renewables/supercritical-geothermal-could-power-everything&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.energymonitor.ai/tech/renewables/supercritical-geothermal-could-power-everything&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;One last thing: The biggest obstacle for Geothermal energy utilization across the globe are not accessibility of geothermal resources or technological capability... its lack of funding.&#xA;Compared to any other energy source, Geothermal is the LEAST funded one of all because myths and outdated information which actually hold no credible accuracy (and are easily countered with more up to date info) are stuck in the minds of many investors (and general population at large).&lt;/p&gt;&#xA;" OwnerUserId="27112" LastEditorUserId="2470" LastEditDate="2022-06-30T00:33:18.903" LastActivityDate="2022-06-30T00:33:18.903" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="23975" PostTypeId="1" CreationDate="2022-06-30T07:41:34.627" Score="1" ViewCount="29" Body="&lt;p&gt;The rate and direction of tectonic movements can be measured by comparing the coordinates of the same GPS receiver over time. The coordinates are obtained using trilateration.&lt;/p&gt;&#xA;&lt;p&gt;All materials I could find on the topic of GPS geolocating implicitly assume that the obliquity and precession of Earth would not change over the period when tectonic movements are measured. This assumption may be right as obliquity and precession change in long enough cycles so that they can be seen as fixed even since the start of space age (1957).&lt;/p&gt;&#xA;&lt;p&gt;It is still interesting to figure out whether and how obliquity and precessional changes of Earth affect the accuracy of GPS-based measurements of tectonic shifts. Let's picture a scenario where as a result of tectonic plates movement, Earth's obliquity and / or precession suddenly change due to redistribution of the planet's mass. Would it be plausible for the new coordinates of GPS receivers to be wrongly calculated? After all, if obliquity and / or precession change, satellites' orbits would intersect the Earth's grid (or graticule) at different positions and angles. The satellites may not be sufficiently adjusted to this new situation, and measured movements of tectonic plates may end up either larger or smaller than the actual values.&lt;/p&gt;&#xA;" OwnerUserId="20732" LastActivityDate="2022-06-30T07:41:34.627" Title="Would obliquity and precessional changes of Earth affect the accuracy of GPS-based measurement of tectonic movements?" Tags="|plate-tectonics|earth-rotation|gravity|axial-obliquity|gps|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23976" PostTypeId="2" ParentId="23972" CreationDate="2022-06-30T08:47:31.133" Score="3" Body="&lt;p&gt;I recently became aware of this dataset and paper, which I think is the sort of thing you're looking for:&lt;/p&gt;&#xA;&lt;p&gt;Tuinenburg et al (2020): Global evaporation to precipitation flows obtained with Lagrangian atmospheric moisture tracking, PANGAEA, &lt;a href=&quot;https://doi.pangaea.de/10.1594/PANGAEA.912710&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.pangaea.de/10.1594/PANGAEA.912710&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Tuinenburg et al (2020): High-resolution global atmospheric moisture connections from evaporation to precipitation, Earth Syst. Sci. Data, 12, 3177–3188, &lt;a href=&quot;https://doi.org/10.5194/essd-12-3177-2020&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.5194/essd-12-3177-2020&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;From which we have Figure 1: The UTrack atmospheric moisture tracking model. (a) The model tracks evaporation through the atmosphere from source cells to target cells using a Lagrangian moisture tracking scheme forced with ERA5 reanalysis data. (b) An example of an “evaporation footprint”, or “evaporation shed”, from the UTrack model. (c) An example of a “precipitation footprint”, or “precipitation shed”:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/k2ppz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/k2ppz.png&quot; alt=&quot;Fig 1 schematic from from Tuinenburg et al (2020)&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I must admit I haven't looked into the data yet, so I don't know how easy it is to use.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2022-06-30T08:47:31.133" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23978" PostTypeId="1" CreationDate="2022-06-30T13:31:28.543" Score="4" ViewCount="32" Body="&lt;p&gt;I am trying to estimate the downward longwave forcing from clouds. I have in-situ measurements of the direct and diffuse components of the incoming shortwave radiation, and I also have the top-of-atmosphere incoming shortwave flux (from reanaslysis).&lt;/p&gt;&#xA;&lt;p&gt;In my scenario the cloud cover is 100% but its thickness is unknown, although I have radiosonde profiles of the temperature/pressure/humidity.&lt;/p&gt;&#xA;&lt;p&gt;My theory is that the higher the ratio of diffuse:direct radiation, the thicker the cloud is. Also, the less global (direct+diffuse) shortwave radiation there is compared to the incident radiation, the thicker it is.  If I know the incoming shortwave flux, and the shortwave coming out, I can partition the rest of the power into absorbed and reflected - can I estimate how much gets turned to longwave and beamed down with some assumptions? I'm thinking particularly that I could use the temperature profile?&lt;/p&gt;&#xA;&lt;p&gt;Clearly this assumption would neglect the upward longwave power from the ground that is re-emmitted downwards from the cloud deck.&lt;/p&gt;&#xA;" OwnerUserId="27121" LastActivityDate="2022-06-30T13:31:28.543" Title="Estimating longwave radiative forcing from clouds from direct/diffuse shortwave components" Tags="|clouds|radiative-transfer|energy-balance|radiation-balance|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23979" PostTypeId="1" AcceptedAnswerId="23981" CreationDate="2022-07-02T11:53:30.510" Score="1" ViewCount="133" Body="&lt;p&gt;I am wondering if denotating a nuclear bomb in the Atlantic Ocean during the hurricane season could trigger a hurricane.&lt;/p&gt;&#xA;&lt;p&gt;For example, say that a 100-megaton bomb was loaded onto a ship and that ship then sailed into an area in the Atlantic Ocean where hurricanes usually form and then the bomb was denotated.&lt;/p&gt;&#xA;&lt;p&gt;I am thinking that perhaps the massive rising fireball of this nuclear explosion would suck in hot moist air in that area, and as this air is pulled inward and upward, this rising air mass would start to rotate, and this upward-moving rotating air mass could trigger a new hurricane.&lt;/p&gt;&#xA;&lt;p&gt;Could a nuclear explosion in the Atlantic Ocean during the hurricane season trigger a hurricane?&lt;/p&gt;&#xA;" OwnerUserId="23275" LastActivityDate="2022-07-02T18:48:09.877" Title="Could a nuclear explosion in the Atlantic Ocean during the hurricane season trigger a hurricane?" Tags="|meteorology|geophysics|tropical-cyclone|geoengineering|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23981" PostTypeId="2" ParentId="23979" CreationDate="2022-07-02T18:48:09.877" Score="4" Body="&lt;p&gt;Hurricanes can only form when oceans reach a specific temperature.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://data.gov/maritime/stormy-weather-150-years-hurricane-tracks-atlantic-ocean/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;picture below&lt;/a&gt; shows the tracks of hurricanes in the Atlantic Ocean for a 150 year period from 1848.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UfybV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UfybV.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;All the tracks are in the northern Atlantic Ocean, there are none in the southern Atlantic. This is because the southern Atlantic ocean is too cold for hurricanes to form.&lt;/p&gt;&#xA;&lt;p&gt;Hurricanes need a lot of warm water to form and they need time to form. &lt;a href=&quot;https://www.counterpunch.org/2008/09/05/the-energy-of-a-hurricane/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Compared to a hurricane&lt;/a&gt;, a nuclear bomb is just a flash in the pan.&lt;/p&gt;&#xA;&lt;p&gt;A hurricane 800 km in diameter and with an eye 80 km in diameter will have an energy of 6.944 × 10&lt;sup&gt;17&lt;/sup&gt; joules, which is the equivalent of 166 megatonnes of TNT. The nuclear bomb dropped on Hirsoshima produced 15 kilotonnes. The hurricane contains 11 times more energy than the bomb dromped on Hiroshima.&lt;/p&gt;&#xA;&lt;p&gt;As I mentioned before, a nuclear bomb is just a flash in the pan. When detonated, the energy is released instantaneously and dissipates very quickly and it does so in a small space.&lt;/p&gt;&#xA;&lt;p&gt;A hurricane however requires time for the vortex to build and in doing so it develops a momentum over a large area that is difficult to stop.&lt;/p&gt;&#xA;&lt;p&gt;Detonating a nuclear bomb in the Atlantic Ocean will not generate a hurricane, it releases too little energy, too quickly, in too small a space.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-07-02T18:48:09.877" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23982" PostTypeId="1" CreationDate="2022-07-04T07:00:35.053" Score="3" ViewCount="164" Body="&lt;p&gt;If the question is a bit confusing, what I'm asking is if there is scientific evidence to counter an argument against climate change that I had come across.&lt;/p&gt;&#xA;&lt;p&gt;The person said that climate change is not a serious issue due to the &amp;quot;globe&amp;quot; having warmed up before in humanity's existence -- specifically &lt;a href=&quot;https://news.northwestern.edu/stories/2019/02/study-shows-that-vikings-enjoyed-a-warm-greenland/#:%7E:text=After%20reconstructing%20southern%20Greenland%27s%20climate,the%20previous%20and%20following%20centuries.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Greenland during the Viking age&lt;/a&gt;, or the Nordic countries.&lt;/p&gt;&#xA;&lt;p&gt;Addendum:  I understand that such an argument against climate change is not factually correct, however, in the spirit of the scientific method I went to look for evidence that pointed either in favor or against this argument... only to then wade through a quagmire of pseudo science and nonsensical claims in favor of this response which are distressingly common.  Thus I ask this question to try to get more clear information.&lt;/p&gt;&#xA;" OwnerUserId="27132" LastEditorUserId="6298" LastEditDate="2022-07-04T18:03:18.803" LastActivityDate="2022-07-05T02:59:13.677" Title="Countering climate change skeptics that point to previous warming episodes" Tags="|climate-change|earth-history|climate-data|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23983" PostTypeId="1" CreationDate="2022-07-04T15:51:28.430" Score="1" ViewCount="48" Body="&lt;p&gt;I interpolated isotopic data (2H or 18O) from 1970 and plotted it on a map. I did the same with data from 2010. The interpolated data are gridded data which have changed over time. Up to now I have only used the Chi-square test as a stochastic evaluation! I wanted to ask you if there are other stochastic or mathematical methods to describe a change in climate data?&lt;/p&gt;&#xA;&lt;p&gt;I am still new in this field and would be happy about even seemingly simple mathematical laws, but more complex ones are also good!&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-07-05T18:34:31.833" LastActivityDate="2022-07-05T18:34:31.833" Title="Describe changes in atmosphere data - mathematical solutions" Tags="|climate-change|climate-models|mathematics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23984" PostTypeId="1" CreationDate="2022-07-04T19:21:31.380" Score="2" ViewCount="13" Body="&lt;p&gt;I am trying to generate an Intensity-Duration-Frequency (IDF) curve using 6-hourly precipitation data. These curves are used to estimate the return period for a rain event with a specific intensity (in mm/hr) and duration. The event duration is on the x-axis which typically ranges from a few minutes to 24 hours, and the rainfall intensity on the y-axis. You get sets of curves, one for each return period. A frequent issue while trying to generate IDF curves from global climate models is the lack of sub-daily output because it is expensive to write out rainfall very frequently (say, 1 hour) in a global climate model that runs 100 years.&lt;/p&gt;&#xA;&lt;p&gt;I currently have 6-hourly data from a global climate model. The literature is filled with references to 'empirical adjustment factors' that essentially generate sub-daily data from lower frequencies. But I am finding it a bit hard to figure out what exactly are these factors. &lt;a href=&quot;https://toolkit.climate.gov/tool/intensity-duration-frequency-curves-new-york-state-future-projections-changing-climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; is an example of what I mean, the link does not even bother to mention what adjustment factors are being used or provide a reference.&#xA;Is there a reference that clearly states what are these factors? Any help is much appreciated.&lt;/p&gt;&#xA;" OwnerUserId="27136" LastEditorUserId="27136" LastEditDate="2022-07-04T19:57:13.110" LastActivityDate="2022-07-04T19:57:13.110" Title="Empirical adjustment factors for generating sub-daily precipitation values (for IDF curves)" Tags="|meteorology|climate-change|hydrology|precipitation|rainfall|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="23985" PostTypeId="1" AcceptedAnswerId="23986" CreationDate="2022-07-04T20:53:39.827" Score="7" ViewCount="490" Body="&lt;p&gt;This is more of a terminological question, but I think it fits here. I've been reading a book by Rachel Carson, from the early 50s, and she uses the phrase &amp;quot;Archaeozic period&amp;quot;. I haven't seen this used elsewhere - is it just an archaic (pardon the pun) form of &amp;quot;Archean&amp;quot;, or does it describe a different period? Etymologically, it seems like it's more oriented around &amp;quot;life&amp;quot;, but that may just be a semantic distinction.&lt;/p&gt;&#xA;" OwnerUserId="27137" LastActivityDate="2022-07-10T00:19:14.417" Title="&quot;Archaeozoic&quot; vs &quot;Archean&quot;" Tags="|terminology|paleogeography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23986" PostTypeId="2" ParentId="23985" CreationDate="2022-07-04T21:40:16.713" Score="8" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Archean&quot; rel=&quot;nofollow noreferrer&quot;&gt;Archaen&lt;/a&gt; was named by American geologist &lt;a href=&quot;https://en.wikipedia.org/wiki/James_Dwight_Dana&quot; rel=&quot;nofollow noreferrer&quot;&gt;James Dwight Dana&lt;/a&gt; in 1872, to refer to the entire span of time before the Cambrian Period.  A synonym was &amp;quot;Azoic&amp;quot; as this period was considered lifeless.&#xA;Later, it was found that the carbon isotope ratios changed in rocks about 3.8 billion years old between ones that indicated no life present to ones that indicated life. So &amp;quot;Azoic&amp;quot; began to refer to the &amp;quot;lifeless&amp;quot; period before 3.8 billion years and &amp;quot;Archaeozoic&amp;quot; for the &amp;quot;earliest life&amp;quot; after that point.&lt;/p&gt;&#xA;&lt;p&gt;That's the way it stood when Rachel Carson wrote her book. The 1969 World Book Encyclopedia which sat on my parents' bookshelf divided the Precambrian into the &lt;a href=&quot;https://en.wikipedia.org/wiki/Proterozoic&quot; rel=&quot;nofollow noreferrer&quot;&gt;Proterozoic&lt;/a&gt;, Archaeozioc, and Azoic eras.&lt;/p&gt;&#xA;&lt;p&gt;By 1972 this wasn't working, so Preston Cloud suggested the term &amp;quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Hadean&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hadean&lt;/a&gt;&amp;quot; to refer to the time between the formation of the Earth/Solar System and 4 billion years ago.  At the same time, the boundary adjustment caused &amp;quot;Archean&amp;quot; to be preferred to &amp;quot;Archaeozoic&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;But &amp;quot;Archaeozoic&amp;quot; matches up enough to be considered a synonym for &amp;quot;Archean&amp;quot; these days.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://pubs.usgs.gov/bul/0769/report.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's a rabbit hole&lt;/a&gt; (PDF) to dive down.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2022-07-10T00:19:14.417" LastActivityDate="2022-07-10T00:19:14.417" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23987" PostTypeId="2" ParentId="23982" CreationDate="2022-07-05T02:59:13.677" Score="4" Body="&lt;p&gt;I suspect what that person is saying is that they think global warming is not actually occurring - that any changes are (like the Medieval Warm Period) naturally occurring and that it won't play out differently over time. But it is easy to show that the warming now is of a different scale than that example -&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/En6KT.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/En6KT.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2022-07-05T02:59:13.677" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23988" PostTypeId="2" ParentId="1060" CreationDate="2022-07-05T16:02:53.367" Score="1" Body="&lt;p&gt;For any late readers: Atmospheric Heat Reduction is possible through the conversion of incoming solar energy to visible light, which is not 'blocked' by green house gases(GHG).  A portion of the visible light will escape the planet, reducing the retained energy in the Earth energy equation.  See takebacktheheat.org for more info.  And yes GHG do not block heat, they play a catch-and-release game where they catch the heat and release it again towards any direction.  If it wasn't there the heat energy could have continued upwards towards space, instead it is caught and released many times with very few being lucky enough to be released upwards towards space by each ghg in the path.&lt;/p&gt;&#xA;&lt;p&gt;Think of a soccer field.  Kick the ball from one end and it'll make it to the other end (space).  But put players in the field, who can receive the ball and re kick it in any direction, and it's less likely to make it to the other end. Add more players, even less likely.  Now make the field and kicks 3 dimensional, and call the players ghg. :)&lt;/p&gt;&#xA;" OwnerUserId="27140" LastEditorUserId="2470" LastEditDate="2022-07-05T16:52:02.237" LastActivityDate="2022-07-05T16:52:02.237" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23989" PostTypeId="2" ParentId="23751" CreationDate="2022-07-05T19:45:17.673" Score="1" Body="&lt;p&gt;This is best answered with the Koschmeider Equation. The Koschmeider Equation which estimates visible range based on the particulate matter is as follows:&lt;/p&gt;&#xA;&lt;p&gt;Koschmeider Equation (units in ft. or m) = (1200 km μg/m^3 )/(particle concentration (μg/m^3 ) )&lt;/p&gt;&#xA;" OwnerUserId="27141" LastActivityDate="2022-07-05T19:45:17.673" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="23990" PostTypeId="1" CreationDate="2022-07-06T14:53:00.720" Score="4" ViewCount="107" Body="&lt;p&gt;From what I read they've been at 3.5% salt equilibrium for millions of years. How is this possible when rivers are constantly flowing dissolving salt into them?&lt;/p&gt;&#xA;" OwnerUserId="27152" LastActivityDate="2022-07-06T15:04:38.093" Title="If the saturation point of saltwater is 26%, why aren't oceans getting saltier over time?" Tags="|oceanography|" AnswerCount="1" CommentCount="1" ClosedDate="2022-07-19T18:21:13.477" ContentLicense="CC BY-SA 4.0" />
  <row Id="23991" PostTypeId="2" ParentId="23990" CreationDate="2022-07-06T15:04:38.093" Score="4" Body="&lt;p&gt;Because salt gets buried over time. Most of the salt we mine is old seas / oceans that dried up and then got buried. Subduction zones carry salt-laden and water-laden sediments very deep underground. The water tends to escape by volcanism. The salt does not.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-07-06T15:04:38.093" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23992" PostTypeId="1" CreationDate="2022-07-06T20:55:11.417" Score="2" ViewCount="68" Body="&lt;p&gt;Recently, I noticed that a highway and a river sound fairly similar. This got me thinking that they say noise pollution from highways causes stress even if you don't really notice it. So, the question is: &amp;quot;Can the noise from a river also be considered as noise pollution (for humans) and cause similar levels of stress.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;Disclaimer: I am not really familiar with environmental sciences&lt;/p&gt;&#xA;" OwnerUserId="27154" LastActivityDate="2022-07-06T20:55:11.417" Title="Noise pollution: Highway vs river" Tags="|rivers|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23993" PostTypeId="1" CreationDate="2022-07-07T06:59:06.487" Score="6" ViewCount="175" Body="&lt;p&gt;I’m usually on Physics SE, but this question seems to fit better into Earth Sciences:&lt;/p&gt;&#xA;&lt;p&gt;I’m interested in radiation transfer and in particular Mie scattering in the atmosphere. So I did some calculation with Miepython (&lt;a href=&quot;https://pypi.org/project/miepython/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://pypi.org/project/miepython/&lt;/a&gt;). Below is an example result for extinction, scattering and backscattering on small water droplets of 1000 nm diameter.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JtSsv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JtSsv.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Unfortunately, I’m a bit puzzled about the results.&lt;/p&gt;&#xA;&lt;p&gt;First, is there any common definition of the angular range in which scattering and backscattering is? The Miepython manual doesn’t state anything about. E.g., is scattering maybe in 0&lt;span class=&quot;math-container&quot;&gt;$^\circ$&lt;/span&gt;-180&lt;span class=&quot;math-container&quot;&gt;$^\circ$&lt;/span&gt; and backscattering in 90&lt;span class=&quot;math-container&quot;&gt;$^\circ$&lt;/span&gt;-180&lt;span class=&quot;math-container&quot;&gt;$^\circ$&lt;/span&gt;?&lt;/p&gt;&#xA;&lt;p&gt;Second, the backscattering shows a lot of variations with wavelength. If I increase the particle size, these get even more. What is the physical explanation for this zig-zag behaviour of alternating maxima and minima?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Update&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;After receiving helpful comments I calculated a polar plot, following instructions from &lt;a href=&quot;https://miepython.readthedocs.io/en/latest/03_angular_scattering.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://miepython.readthedocs.io/en/latest/03_angular_scattering.html&lt;/a&gt; (incl. axes labeling...) for unpolarized radiation.&lt;/p&gt;&#xA;&lt;p&gt;The result is:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9DAql.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9DAql.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, I tried to integrate (sum up) over different ranges and multiplied by the geometric cross section (what miepython requires you to do, and which has been done already for the plots above), but couldn't reproduce numbers of the above plot at 500 nm.&lt;/p&gt;&#xA;" OwnerUserId="27156" LastEditorUserId="27156" LastEditDate="2022-07-07T12:15:17.983" LastActivityDate="2023-03-30T23:51:45.483" Title="Interpretation of Mie scattering" Tags="|atmospheric-radiation|radiative-transfer|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="23994" PostTypeId="1" CreationDate="2022-07-07T10:39:06.977" Score="1" ViewCount="242" Body="&lt;p&gt;In this image from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ozone_layer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia ozone layer page&lt;/a&gt; there are positive (normal) and negative latitudes on the bottom axis:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sKeOm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sKeOm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Are the negative latitudes those north or those south of the equator?&lt;/p&gt;&#xA;" OwnerUserId="27157" LastEditorUserId="6298" LastEditDate="2022-07-07T17:06:51.553" LastActivityDate="2022-07-08T10:55:29.723" Title="What are negative latitudes?" Tags="|mapping|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="23995" PostTypeId="1" CreationDate="2022-07-07T14:30:57.083" Score="3" ViewCount="41" Body="&lt;p&gt;I hope to find a GIS resource for the IPCC definitions of climate zones, e.g.&#xA;&lt;em&gt;&amp;quot;Temperate, cold climate: Areas where mean annual temperature (MAT) is between 0 – 10 C, and the ratio of mean annual precipitation to potential evapotranspiration is less than or equal to 1&amp;quot;&lt;/em&gt;. With the necessary data it is possible to derive these myself, but unfortunately I don't have the climate and elevation files available and was hoping that such a map is already published.&lt;/p&gt;&#xA;" OwnerUserId="27158" LastActivityDate="2022-07-07T14:30:57.083" Title="Is there a georeferenced map/GIS resource for the IPCC definitions of climate zone available?" Tags="|climate-data|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23996" PostTypeId="1" CreationDate="2022-07-07T14:53:39.690" Score="4" ViewCount="72" Body="&lt;p&gt;Per &lt;a href=&quot;https://en.wikipedia.org/wiki/Ozone_layer#/media/File:Nimbus_ozone_Brewer-Dobson_circulation.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;this image&lt;/a&gt; shown below, the largest concentration of the ozone layer above the northern hemisphere is at a lower altitude than the largest concentration above the southern hemisphere. However, temperature near the South Pole is lower than near the North Pole. Therefore, I'd expect the atmosphere is more compressed in the south and therefore the ozone layer would be lower there. So what's the reason the ozone layer actually peaks lower on the northern hemisphere?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JcJbT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JcJbT.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Edit: On &lt;a href=&quot;https://www.researchgate.net/figure/Brewer-Dobson-circulation-and-the-distribution-of-ozone-This-meridional-cross-section_fig1_260315664&quot; rel=&quot;nofollow noreferrer&quot;&gt;this image&lt;/a&gt; you can see it better: There is this giant red spot on the North Pole. Why is the ozone concentration so strong there?&lt;/p&gt;&#xA;" OwnerUserId="27157" LastEditorUserId="6298" LastEditDate="2022-07-07T17:15:45.640" LastActivityDate="2022-07-07T17:15:45.640" Title="Why is the ozone layer in the northern hemisphere at lower altitudes than in the southern hemisphere?" Tags="|atmospheric-chemistry|ozone|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="23997" PostTypeId="2" ParentId="23994" CreationDate="2022-07-07T15:45:20.243" Score="3" Body="&lt;p&gt;The negative latitudes are south.&lt;/p&gt;&#xA;&lt;p&gt;Just as values to the right of the origin on the x axis and above the origin on the y axis in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cartesian_coordinate_system&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cartesian plane&lt;/a&gt; are positive, and those down/left are negative, values east/north are very commonly written as positive and those west/south are commonly written as negative.  This, for one, allows for continual mathematical representation of latitude and longitude.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/yzSEWm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/yzSEWm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Sometimes you &lt;a href=&quot;https://mathematica.stackexchange.com/questions/18150/define-the-range-of-longitude-from-0-360-in-the-world-plot-from-countrydata&quot;&gt;may also see&lt;/a&gt; longitude labeled from 0° to +360°.  This choice can be a benefit to allow Asia and the Pacific Ocean to be more central in a global plot; most applications that plot geographic coordinates will be easiest to setup over a continual domain.  But I have never seen anything but negative latitudes for those south of the equator.&lt;/p&gt;&#xA;&lt;p&gt;Could they be labeled that way?  Sure, if you really want to.  Just as with angles in a circle in general, latitude and longitude could feasibly be setup over any 360° range, and are truly &lt;a href=&quot;https://www.youtube.com/watch?v=x8Db7kqILNI&quot; rel=&quot;nofollow noreferrer&quot;&gt;periodic&lt;/a&gt; (to get a repeated map as &lt;a href=&quot;https://i.stack.imgur.com/fx2mE.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;OpenStreetMaps still shows at widest zoom as of today&lt;/a&gt; you'd do 0° to 1080° longitude or such in many plotting programs... longitudes of 270° to 450° would be positive values that should work to get a single repeat of latitude).  We happened to settle on the choice of the equator and Prime Meridian as the typical references (&lt;a href=&quot;https://en.wikipedia.org/wiki/Prime_meridian_(Greenwich)#History&quot; rel=&quot;nofollow noreferrer&quot;&gt;in part Eurocentric indeed&lt;/a&gt;), and the east/north increasing standard; gladly navigation developed contemporaneously with larger mathematics (they kind of spurred each other on), or you could have somewhat differently defined systems, like &lt;a href=&quot;https://www.youtube.com/watch?v=hREmYWBgvUQ&quot; rel=&quot;nofollow noreferrer&quot;&gt;bearing versus cartesian angles&lt;/a&gt;, or various unit systems, to make conversion a bit of extra work.&lt;/p&gt;&#xA;&lt;p&gt;Having east/north is generally simplest as it matches the Cartesian coordinate system.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-07-08T10:55:29.723" LastActivityDate="2022-07-08T10:55:29.723" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23998" PostTypeId="1" AcceptedAnswerId="24001" CreationDate="2022-07-08T07:52:05.500" Score="3" ViewCount="91" Body="&lt;p&gt;The melting of the North Polar ice masses removes a driving factor from the thermohaline circulation, known as the Gulf Stream in the North Atlantic. I wonder how much the thermohaline circulation has reduced in intensity over the last 60 years?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="18081" LastEditDate="2023-07-26T20:14:49.020" LastActivityDate="2023-07-26T20:14:49.020" Title="Change in thermohaline circulation due to climate change" Tags="|climate-change|climate-models|ice|arctic|thermohaline-circulation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="23999" PostTypeId="1" CreationDate="2022-07-08T21:01:10.037" Score="1" ViewCount="40" Body="&lt;p&gt;I am looking for a book (and/or show) that tackles geology on a popular science level from a historical perspective with biographical components of the scientists / discoverers involved in moving the field forward.&lt;/p&gt;&#xA;&lt;p&gt;I have come across these types of works for other fields - e.g., &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/0316051632&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Disappearing Spoon&lt;/a&gt; for chemistry, and several episodes of Cosmos have this kind of narrative form for physics and astronomy. They are useful because they are simple, engaging, and give an idea of questions that were being asked over time and how they were resolved. So they can be nice for gaining a broad overview of a subject if you're a novice, which I am.&lt;/p&gt;&#xA;&lt;p&gt;Does anyone have any recommendations?&lt;/p&gt;&#xA;&lt;p&gt;Thanks for any help!&lt;/p&gt;&#xA;" OwnerUserId="13460" LastEditorUserId="18081" LastEditDate="2022-08-04T09:09:19.390" LastActivityDate="2022-08-04T09:09:19.390" Title="Book recommendation - historical / biographrical take on geology?" Tags="|geology|reference-request|history|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24000" PostTypeId="1" CreationDate="2022-07-09T11:29:34.863" Score="2" ViewCount="119" Body="&lt;p&gt;Is there any known evidence about what the local time of day of the Chicxulub impact was (at the very least, whether the impactor struck during day or night)?&lt;/p&gt;&#xA;&lt;p&gt;If there is not any such known evidence, then is there any known form/mechanism of scientific evidence that we might be able to find or examine that could reveal the local time of day?&lt;/p&gt;&#xA;" OwnerUserId="27166" LastEditorUserId="27166" LastEditDate="2022-07-09T11:33:47.663" LastActivityDate="2022-07-09T11:33:47.663" Title="Time of day of Chicxulub impact" Tags="|geology|earth-history|impacts|cretaceous|impact-craters|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24001" PostTypeId="2" ParentId="23998" CreationDate="2022-07-09T15:20:30.610" Score="4" Body="&lt;p&gt;Climate models predict that under the influence of anthropogenic warming, the AMOC will decline during this century at a rate between 0 and 0.9 Sv per decade (1 Sv = 1 Mio. m3 s−1)                                                           For a warming of 1,5-2/2-3/3-5°C in 2100, the AMOC decline is 29/32/39% respectively to its pre-industrial strenght.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/s41561-021-00699-z/figures/1&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/s41561-021-00699-z/figures/1&lt;/a&gt;                &lt;a href=&quot;https://climatetippingpoints.files.wordpress.com/2021/09/image-9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://climatetippingpoints.files.wordpress.com/2021/09/image-9.png&lt;/a&gt;    &lt;a href=&quot;https://climatetippingpoints.files.wordpress.com/2021/08/image-4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://climatetippingpoints.files.wordpress.com/2021/08/image-4.png&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26198" LastActivityDate="2022-07-09T15:20:30.610" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24002" PostTypeId="1" CreationDate="2022-07-11T03:49:13.663" Score="1" ViewCount="78" Body="&lt;p&gt;What is the true time in Perth western Australia when the sun directly overhead, given that the state time is calculated at Southern Cross.&lt;/p&gt;&#xA;" OwnerUserId="27170" LastEditorUserId="2470" LastEditDate="2022-07-11T10:09:26.060" LastActivityDate="2022-07-11T16:09:51.090" Title="What is the true time when the sun is directly over Perth given that the W.A. time is taken from Southern Cross" Tags="|time|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24003" PostTypeId="2" ParentId="24002" CreationDate="2022-07-11T11:12:58.407" Score="1" Body="&lt;p&gt;I find the statement that time in Western Australia is based the location of Southern Cross somewhat speculative. Some supportive evidence would improve the question.&lt;/p&gt;&#xA;&lt;p&gt;Given the history of British colonization of Western Australia, Southern Cross was established many years after the initial two settlements of Albany and Perth.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Albany%2C_Western_Australia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Albany&lt;/a&gt; was initially established as a military outpost in 1826.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Perth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Perth&lt;/a&gt; was establish in 1829, initially called the Swan River Colony. It was established as the seat of colonial administration &amp;amp; eventually government for the then colony and still remains so.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Southern_Cross%2C_Western_Australia&quot; rel=&quot;nofollow noreferrer&quot;&gt;Southern Cross&lt;/a&gt; was established in 1890, some 61 years after the establishment of Perth. Government authorities in Perth would not have waited 61 years to establish a system of keeping time in Perth and the rest of the colony.&lt;/p&gt;&#xA;&lt;p&gt;The lines of longitude (eastings) and the time difference from the Greenwich meridian for the three locations are:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;\begin{array}{|c|c|c|}&#xA;\hline&#xA;  \text{Location} &amp;amp; \text{Easting} &amp;amp; \text{Time from Greenwich}\\ &#xA;\hline&#xA;   {Perth} &amp;amp; 115^o\ 51'\ 38&quot;  &amp;amp; 7h\ 43'\ 27&quot; \\&#xA;\hline&#xA;   {Albany} &amp;amp; 117^o\ 52'\ 53&quot; &amp;amp; 7h\ 51'\ 32&quot; \\&#xA;\hline&#xA;   {Southern\ Cross} &amp;amp; 119^o\ 19'\ 40&quot; &amp;amp; 7h\ 57'\ 19&quot; \\ &#xA;\hline&#xA;\end{array}&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The times are based in the Earth rotating effectively 360° in 24 hours, or at a rate of 15° per hour.&lt;/p&gt;&#xA;&lt;p&gt;For the colonial authorities in 1829, 7 hours 43 minutes and 27 seconds would have been close enough 8 hours from the Greenwich meridian to set the time for the colony to be 8 hours ahead of Greenwich. The fact that Southern Cross is only 2 minutes 41 seconds short of 8 hours time difference from Greenwich is a coincidence.&lt;/p&gt;&#xA;&lt;p&gt;When the Sun is directly overhead in Perth the so called &amp;quot;true time&amp;quot; is 12h 16' 33&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="6298" LastEditDate="2022-07-11T16:09:51.090" LastActivityDate="2022-07-11T16:09:51.090" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24004" PostTypeId="1" AcceptedAnswerId="24005" CreationDate="2022-07-12T07:52:14.230" Score="6" ViewCount="1324" Body="&lt;p&gt;Where do I find the documentation of different &lt;code&gt;VARIANT-ID&lt;/code&gt;s for the CMIP6 dataset? A VARIANT-ID is of the format &lt;code&gt;r&amp;lt;k&amp;gt;i&amp;lt;l&amp;gt;p&amp;lt;m&amp;gt;f&amp;lt;n&amp;gt;&lt;/code&gt;, where the characters &lt;code&gt;r&lt;/code&gt;, &lt;code&gt;i&lt;/code&gt;, &lt;code&gt;p&lt;/code&gt; and &lt;code&gt;f&lt;/code&gt; denote:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;r-realisation&lt;br /&gt;&#xA;i-initialisation method&lt;br /&gt;&#xA;p-physics&lt;br /&gt;&#xA;f-forcing&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I checked the overview paper &lt;a href=&quot;https://www.geosci-model-dev.net/9/1937/2016/&quot; rel=&quot;noreferrer&quot;&gt;Eyring et al. (2016)&lt;/a&gt;, but it doesn't mention anything about VARIANT-ID. I have also checked other documents provided at &lt;a href=&quot;https://esgf-node.llnl.gov/projects/cmip6/&quot; rel=&quot;noreferrer&quot;&gt;ESGF&lt;/a&gt;, but couldn't find any information.&lt;/p&gt;&#xA;&lt;p&gt;Does anyone here knows where I can find detailed information about the &lt;code&gt;VARIANT-ID&lt;/code&gt; for CMIP6 datasets?&lt;/p&gt;&#xA;" OwnerUserId="9633" LastEditorUserId="9633" LastEditDate="2022-07-12T09:48:19.183" LastActivityDate="2022-07-12T11:41:52.457" Title="Where can I find detailed description of different VARIANT-IDs in CMIP6 metadata?" Tags="|climate-models|earth-system|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24005" PostTypeId="2" ParentId="24004" CreationDate="2022-07-12T09:23:42.743" Score="8" Body="&lt;p&gt;The variant_labels are defined in the &lt;a href=&quot;https://docs.google.com/document/d/1h0r8RZr_f3-8egBMMh7aqLwy3snpD6_MrDz1q8n5XUk/edit&quot; rel=&quot;noreferrer&quot;&gt;CMIP6 Data Reference Syntax (DRS)&lt;/a&gt; document and are made up of the realization_index, initialization_index, physics_index and forcing_index.&lt;/p&gt;&#xA;&lt;p&gt;A link to this DRS document can for example be found in the &lt;a href=&quot;https://pcmdi.llnl.gov/CMIP6/Guide/modelers.html&quot; rel=&quot;noreferrer&quot;&gt;CMIP6 Participation Guide for Modelers&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Edit: Following up Deditos' comment, I quote the respective section of the DRS document below:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;For a given experiment, the realization_index, initialization_index,&#xA;physics_index, and forcing_index are used to uniquely identify each&#xA;simulation of an ensemble of runs contributed by a single model.&#xA;These indices are defined as follows:&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;realization_index = an integer (≥1) distinguishing among members of an ensemble of simulations that differ only in their initial conditions (e.g., initialized from different points in a control run).  Note that if two different simulations were started from the same initial conditions, the same realization number should be used for both simulations.  For example if a historical run with “natural forcing” only and another historical run that includes anthropogenic forcing were both spawned at the same point in a control run, both should be assigned the same realization.  Also, each so-called RCP (future scenario) simulation should normally be assigned the same realization integer as the historical run from which it was initiated.  This will allow users to easily splice together the appropriate historical and future runs.&lt;/li&gt;&#xA;&lt;li&gt;initialization_index = an integer (≥1), which should be assigned a value of 1 except to distinguish simulations performed under the same conditions but with different initialization procedures.  In CMIP6 this index should invariably be assigned the value “1” except for some hindcast and forecast experiments called for by the DCPP activity.  The initialization_index can be used either to distinguish between different algorithms used to impose initial conditions on a forecast or to distinguish between different observational datasets used to initialize a forecast.&lt;/li&gt;&#xA;&lt;li&gt;physics_index = an integer (≥1) identifying the physics version used by the model.  In the usual case of a single physics version of a model, this argument should normally be assigned the value 1, but it is essential that a consistent assignment of physics_index be used across all simulations performed by a particular model.  Use of  “physics_index” is reserved for closely-related model versions (e.g., as in a “perturbed physics” ensemble) or for the same model run with slightly different parameterizations (e.g., of cloud physics).  Model versions that are substantially different from one another should be given a different source_id” (rather than simply assigning a different value of the physics_index).&lt;/li&gt;&#xA;&lt;li&gt;forcing_index = an integer (≥1) used to distinguish runs conforming to the protocol of a single CMIP6 experiment, but with different variants of forcing applied.  One can, for example, distinguish between two historical simulations, one forced with the CMIP6-recommended forcing data sets and another forced by a different dataset, which might yield information about how forcing uncertainty affects the simulation.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Each data provider can assign whatever positive integers they like&#xA;for the realization_index, intialization_index, physics_index, and&#xA;forcing index.  For each source/experiment pair, however, consistency&#xA;(in these indices) should be maintained across each parent/child pair&#xA;whenever sensible (so that, for example, both the ScenarioMIP child&#xA;and its “historical” parent simulation would be assigned the same set&#xA;of index values for realization, initialization, and physics); the&#xA;integer 1 should normally be chosen for each of these in the case of a&#xA;single variant or for the primary variant (if there is one).  This is&#xA;only a suggestion, however; there should be no expectation on the part&#xA;of users that every model will have a value of 1 assigned to any of&#xA;the r, i, p, f indices, and even if a 1 is assigned it does not imply&#xA;that it is the primary variant.  Note also that a child spawned by a&#xA;control run will not  necessarily have the same “ripf” value as the&#xA;control,  since, for example, multiple realizations of an experiment&#xA;will  branch from the same control.&lt;/p&gt;&#xA;&lt;p&gt;Note that none of the “ripf” indices can be omitted.&lt;/p&gt;&#xA;&lt;p&gt;Example of a variant_label:  if realization_index=2,&#xA;initialization_index=1, physics_index=3, and forcing_index=233, then&#xA;variant_label = “r2i1p3f233”.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="27172" LastEditorUserId="27172" LastEditDate="2022-07-12T11:41:52.457" LastActivityDate="2022-07-12T11:41:52.457" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24006" PostTypeId="1" CreationDate="2022-07-13T09:22:59.540" Score="4" ViewCount="79" Body="&lt;p&gt;Near the summit of Mauna Loa there are two observatories. Mauna Loa is an active volcano that is being watched, so why did they build observatories up there instead of building them on the dormant and slightly higher Mauna Kea? Once Mauna Loa erupts the observatories would be gone, wouldn't they? And even outside full eruptions, isn't it dangerous anyway to build an observatory near an active volcanic summit due to earthquakes, plumes and stuff?&lt;/p&gt;&#xA;" OwnerUserId="27157" LastActivityDate="2022-07-13T09:22:59.540" Title="Why on Earth are there observatories on the active Mauna Loa?" Tags="|volcanology|seismology|magma-plumes|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24007" PostTypeId="1" CreationDate="2022-07-13T12:31:19.203" Score="1" ViewCount="43" Body="&lt;p&gt;I have a simple question about the Chi-Square test (unfortunately I only had the extreme maths basics when I was in university). I have the following results:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gjAKa.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gjAKa.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I think I will use the old data as expected frequency and the new data as observed frequency. My result is as follows.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;               id  New       old     Chisquare&#xA;0      (-26, -22]  17858.0  31704.0  10735.340800&#xA;1      (-22, -18]  16060.0  18990.0    534.551681&#xA;2      (-18, -14]  20023.0  13964.0   1833.465565&#xA;3      (-14, -10]  19845.0   5573.0  10264.045553&#xA;4       (-10, -6]  12757.0    779.0  11246.569256&#xA;5        (-6, -2]   6446.0      0.0   6446.000000&#xA;6         (-2, 2]   1391.0      0.0   1391.000000&#xA;&#xA;Total              94380.0  71010.0  42450.972855&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;how can i calculate the p value? i have 4 lines of freedom! I use the python code for this:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;1 - stats.chi2.cdf((total(Chi^2)), 4)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;But my result is:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;&amp;gt;&amp;gt;&amp;gt; 1 - stats.chi2.cdf(42450.972855, 4)&#xA;0.0&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;So I wanted to ask if this can be correct, although a change in the data can be recognised in the figure.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2022-07-13T12:31:19.203" Title="Chi-Suare Test: p-Value" Tags="|statistics|python|" AnswerCount="0" CommentCount="1" ClosedDate="2022-07-23T11:58:31.843" ContentLicense="CC BY-SA 4.0" />
  <row Id="24008" PostTypeId="1" CreationDate="2022-07-13T13:21:37.450" Score="26" ViewCount="4768" Body="&lt;p&gt;On Google Earth, there are these radiating undersea lines all around Hawaii:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9oyC5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9oyC5.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here with a bit more contrast:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lNaqv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lNaqv.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Unlike the other lines, they are pointed away (or toward) a single place.&lt;/p&gt;&#xA;&lt;p&gt;What are these, how are they called and how did they form?&lt;/p&gt;&#xA;" OwnerUserId="27177" LastEditorUserId="26841" LastEditDate="2022-08-17T18:08:56.953" LastActivityDate="2022-08-18T20:27:09.500" Title="What are these undersea lines all around Hawaii?" Tags="|geophysics|oceanography|earth-history|satellite-oddities|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24009" PostTypeId="2" ParentId="24008" CreationDate="2022-07-13T13:30:32.620" Score="10" Body="&lt;p&gt;Hawai was created by a coat of plume. This means that hot material rises and penetrates the oceanic currents! These are fracture marks from this process.&lt;/p&gt;&#xA;&lt;p&gt;Secondly, the plate is torn apart by subduction under the N Amrican continent. This contributes to the formation of these fractures&lt;/p&gt;&#xA;&lt;p&gt;See this figure:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/DGSfT.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DGSfT.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source and also interesting to read: &lt;a href=&quot;https://www.pnas.org/doi/10.1073/pnas.1300192110&quot; rel=&quot;noreferrer&quot;&gt;https://www.pnas.org/doi/10.1073/pnas.1300192110&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As outher Answers sugesst: it is also a side effect formed by seafloor spreading&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-07-14T07:02:56.827" LastActivityDate="2022-07-14T07:02:56.827" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24010" PostTypeId="2" ParentId="24008" CreationDate="2022-07-13T14:53:56.833" Score="31" Body="&lt;p&gt;Short answer: The lines radiating from the island are  artifacts from a mapping process that superimposes high-resolution sonar data from standard ship tracks on top of r low- or average sonar data for the region.&lt;/p&gt;&#xA;&lt;p&gt;Long answer: All the seafloor geography in these maps comes from sonar, ship soundings, or other remote sensing methods and that data is affected by how it is gathered. (Satellites and airborne cameras, radar and lidar can't see through the ocean deeper than a few meters at best, so seafloor imagery is not photographic data.)&lt;/p&gt;&#xA;&lt;p&gt;Some of the visual elements that appear to be seafloor geography -- notably straight lines radiating away from single points and gridlike formations -- are actually artifacts from the way ships travel. That is, most of the mapping data comes from research vessels using high-resolution sonar while cruising from one location to another, making data collected along those tracks appear much different from the low-resolution details of the general map. As a result, you will often see lines of high-resolution data radiating from ports and islands and grid-like formations where ships have run transects.&lt;/p&gt;&#xA;&lt;p&gt;Here's a map from the &lt;a href=&quot;https://www.soest.hawaii.edu/hmrg/multibeam/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;School of Ocean and Earth Science and Technology and the Hawaii Mapping Research Group&lt;/a&gt; synthesizing the available data into a more accurate high-resolution representation of the seafloor.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/h3iaK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/h3iaK.jpg&quot; alt=&quot;Multibeam synthesis map of the Hawaii Islands&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://scripps.ucsd.edu/news/google-earth-ocean-terrain-receives-major-update&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's one story about how improved data and methodology removed visual artifacts that made people think there was an underground structure in the Atlantic.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The remaining east-west lines are &lt;a href=&quot;https://en.wikipedia.org/wiki/Fracture_zone&quot; rel=&quot;nofollow noreferrer&quot;&gt;fracture zones&lt;/a&gt; that are side-effects of seafloor spreading.&lt;/p&gt;&#xA;&lt;p&gt;Here's a wider geodetic map of the region from one of the sources used by Google maps where you can see the fracture zones more clearly:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/4vAlq.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4vAlq.jpg&quot; alt=&quot;Map of seafloor around Hawaii&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7314" LastEditorUserId="7314" LastEditDate="2022-08-18T20:27:09.500" LastActivityDate="2022-08-18T20:27:09.500" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="24011" PostTypeId="1" AcceptedAnswerId="24012" CreationDate="2022-07-14T08:03:18.343" Score="12" ViewCount="3971" Body="&lt;p&gt;I keep reading that final storage sites for nuclear waste are being built in salt domes. In the case of the German Gorleben project, the salt domes &lt;a href=&quot;https://www.base.bund.de/SharedDocs/Pressemitteilungen/BASE/EN/2021/0917_gorleben.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;were determined to be unsuitable&lt;/a&gt; after prolonged investigation.&lt;/p&gt;&#xA;&lt;p&gt;Regardless of the Gorleben case, why are salt domes preferred?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="6298" LastEditDate="2022-07-17T10:25:54.213" LastActivityDate="2022-07-17T10:25:54.213" Title="Why are salt domes suitable for the final disposal of nuclear waste?" Tags="|geology|uranium|hazardous|ionizing-radiation|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24012" PostTypeId="2" ParentId="24011" CreationDate="2022-07-14T08:06:44.060" Score="10" Body="&lt;p&gt;Hi Salt domes have formed over a period of several million years. These salt domes are usually also very well sealed against water by a protective layer (Anhydrite) (salt dissolves in water and if the salt dome were not dry it would not exist). These drying conditions, in addition to an already existing infrastructure through salt mining, are the reason why salt domes are used as nuclear repositories.&lt;/p&gt;&#xA;&lt;p&gt;Have a Look: &lt;a href=&quot;https://www.sciencedaily.com/releases/2020/04/200429075857.htm&quot; rel=&quot;noreferrer&quot;&gt;https://www.sciencedaily.com/releases/2020/04/200429075857.htm&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2yxE4.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2yxE4.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://antisocialnetwork-2labz.blogspot.com/2017/04/rock-salt-for-dummies-freelance-files_15.html&quot; rel=&quot;noreferrer&quot;&gt;https://antisocialnetwork-2labz.blogspot.com/2017/04/rock-salt-for-dummies-freelance-files_15.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-07-14T08:16:36.323" LastActivityDate="2022-07-14T08:16:36.323" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24013" PostTypeId="1" CreationDate="2022-07-14T10:21:32.297" Score="2" ViewCount="96" Body="&lt;p&gt;When watching &lt;a href=&quot;https://www.youtube.com/watch?v=iAlS70Onn2I&amp;amp;ab_channel=DaveVE3OOI&quot; rel=&quot;nofollow noreferrer&quot;&gt;this high altitude balloon video&lt;/a&gt; I stumbled across a weird thing: Go to 6:08 and watch as the black sky suddenly turns to blue due to a different camera position. This is an image from about 87,000 ft (26.5 km) altitude, and despite (or because of?) no longer looking towards the Sun the entire sky suddenly turns into blue for a moment. Usually, on such nearspace videos I observed the opposite: the black sky gets a bit blue around the Sun, that's obviously due to the light scattering by the very thin atmosphere when looking towards the Sun. But I haven't seen the opposite so far, except that I've seen somewhat contradictory videos concerning the sky color at the same altitude (which includes videos by ascending rocket onboard cameras).&lt;/p&gt;&#xA;&lt;p&gt;Why does the otherwise black sky suddenly turn blue in the footage and what does the sky &lt;em&gt;really&lt;/em&gt; look like around 87,000 ft to the human eye (I've never been to these altitudes myself)?&lt;/p&gt;&#xA;" OwnerUserId="27157" LastActivityDate="2022-07-15T08:13:27.113" Title="Why does the camera do this and what does the sky really look like around 87,000 ft altitude?" Tags="|atmosphere|light|stratosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24014" PostTypeId="1" CreationDate="2022-07-14T10:32:08.307" Score="4" ViewCount="111" Body="&lt;p&gt;&lt;strong&gt;Banks and Kockarts, in &lt;em&gt;Aeronomy (Part B)&lt;/em&gt;&lt;/strong&gt;, has provided &lt;em&gt;an illustration of the vertical distribution of the mean free path of atomic hydrogen for several thermopause temperatures&lt;/em&gt; (Fig. 16.3, p.84/362). I am working to understand the &lt;em&gt;mean free path of species&lt;/em&gt; and its relation to the &lt;em&gt;scale height at the exobase&lt;/em&gt; by solving the aforementioned Fig.16.3. The following is what I performed to achieve this.&lt;/p&gt;&#xA;&lt;p&gt;For thermosphere, assuming for atomic hydrogen a number density (n) of 10&lt;sup&gt;8&lt;/sup&gt; per cm&lt;sup&gt;3&lt;/sup&gt;, and cross section (&lt;span class=&quot;math-container&quot;&gt;$\sigma$&lt;/span&gt;) of 2.8 &lt;span class=&quot;math-container&quot;&gt;$\times$&lt;/span&gt; 10&lt;sup&gt;-15&lt;/sup&gt; cm&lt;sup&gt;2&lt;/sup&gt;, I could calculate a mean free path (mfp) of 14.86 km (mfp = &lt;span class=&quot;math-container&quot;&gt;$\frac{1}{\sqrt2. n. \sigma}$&lt;/span&gt;).&lt;/p&gt;&#xA;&lt;p&gt;At the altitude of the thermopause of 500 km, I calculated the acceleration due to gravity as 8.43 m/s&lt;sup&gt;2&lt;/sup&gt;. Then, for a thermospheric temperature of 2000 K, calculated the scale height (H = &lt;span class=&quot;math-container&quot;&gt;$\frac{kT}{mg}$&lt;/span&gt;) for the atomic hydrogen as &lt;span class=&quot;math-container&quot;&gt;$\approx$&lt;/span&gt; 1961 km.&lt;/p&gt;&#xA;&lt;p&gt;Now, how to calculate the altitude at which the &lt;em&gt;mean free path&lt;/em&gt; is equal to the &lt;em&gt;atmospheric scale height&lt;/em&gt;?&lt;/p&gt;&#xA;&lt;p&gt;Kindly help to equate mfp and H to find the altitude. Also, help me to understand the concept I am missing here.&lt;/p&gt;&#xA;" OwnerUserId="27183" LastEditorUserId="27183" LastEditDate="2022-07-14T12:17:13.057" LastActivityDate="2022-07-14T12:17:13.057" Title="Mean free path and Scale height" Tags="|atmosphere|temperature|altitude|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24015" PostTypeId="1" AcceptedAnswerId="24017" CreationDate="2022-07-14T13:21:05.563" Score="1" ViewCount="182" Body="&lt;p&gt;My son answered e), but Scantron marked him wrong. Why?  Please show the steps. How should he deduce the answer?&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;A picture was taken in the Northern Hemisphere (e.g. Canada), featuring two skyscrapers. You can clearly see sunlight coming from the right hand side of the picture,  gleaming &lt;strong&gt;just&lt;/strong&gt; the right side of these skyscrapers. &lt;em&gt;No sunlight whatsoever glistens their left side.&lt;/em&gt; What direction must the camera been facing?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;a) North&lt;br /&gt;&#xA;b) South&lt;br /&gt;&#xA;c) East&lt;br /&gt;&#xA;d) West&lt;br /&gt;&#xA;e) More information is needed to answer this question.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user17042" LastEditorDisplayName="user17042" LastEditDate="2022-07-14T15:28:30.473" LastActivityDate="2022-07-14T15:28:30.473" Title="In a picture taken in Northern Hemisphere, the sun shines on skyscrapers solely from the right. What direction was the camera facing?" Tags="|sun|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24016" PostTypeId="2" ParentId="24011" CreationDate="2022-07-14T13:32:35.213" Score="22" Body="&lt;p&gt;Using salt domes in which to store nuclear waste has been considered in the USA and Germany. These two countries have potentially suitable salt domes.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ncbi.nlm.nih.gov/books/NBK208696/&quot; rel=&quot;noreferrer&quot;&gt;&lt;strong&gt;Factors in favor of salt domes&lt;/strong&gt;&lt;/a&gt; are (Sect 12 of the reference):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Salt is already mined from such domes in the USA. The voids left&#xA;behind provide reduce the cost of nuclear waste storage. The cost of&#xA;producing the voids is absorbed by corporations mining the deposit&#xA;for salt. The nuclear waste disposing entities spend less money&#xA;digging fewer holes.&lt;/li&gt;&#xA;&lt;li&gt;Salt deposits are geologically stable, having existed for millions of&#xA;years.&lt;/li&gt;&#xA;&lt;li&gt;More so in the USA, the geological setting of the deposits is also&#xA;secure. The salt domes are in regions with low seismicity.&lt;/li&gt;&#xA;&lt;li&gt;In bedded salt deposits the overlying strata such as limestone and&#xA;dolomite provide truss-like support to the overburden. The&#xA;possibility of roof collapse causing the release of radioactive&#xA;materials stored under these conditions appears very small but merits&#xA;verification.&lt;/li&gt;&#xA;&lt;li&gt;Salt is a good thermal conductor and will supposedly dissipate the&#xA;heat from the nuclear waste. I would be more comfortable with this&#xA;reason if the containers of nuclear waste were placed directly into&#xA;specially sized holes within the salt domes, where the containers are&#xA;in maximum direct contact with the salt. If the containers of nuclear&#xA;waste are simply placed in within the air space of the underground&#xA;chamber the waste must first heat the air which then heats the walls&#xA;of the salt chamber. The dissipation of heat takes longer.&lt;/li&gt;&#xA;&lt;li&gt;Salt domes are only secure if they are mined by mechanical means:&#xA;drilling and blasting or grinding. Salt domes mined by aqueous&#xA;methods - dissolving the salt with water and removing the salt as&#xA;brine produces underground chambers with no internal support, such as&#xA;pillars or human installed rock or cable bolts which reinforce the&#xA;walls and ceiling of underground chambers. Such chambers would be&#xA;unsuitable and could be prone to collapse.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;Issues with using salt domes&lt;/strong&gt; to store nuclear waste:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Salt is generally regarded as being self healing. Any small cracks&#xA;that may develop within the salt deposit will close. This applies to&#xA;small cracks, but may not apply to very large cracks.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Salt domes are generally considered to inhibit the flow of fluids&#xA;through them. However, under conditions of high temperature and&#xA;pressure, as exists deep underground, &lt;a href=&quot;https://www.popsci.com/storing-nuclear-waste-in-salt-deposits-isnt-as-secure-as-youd-think/&quot; rel=&quot;noreferrer&quot;&gt;salt can become more&#xA;porous&lt;/a&gt; allowing more fluids to pass through it. This can be&#xA;problematic if in flowing water was to pick up radioactive material&#xA;and start spreading it around the region of the salt dome.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The nature of the nuclear waste to be stored needs to be considered.&#xA;Salt domes would be better at storing solid waste. Some waste is&#xA;liquid which can more easily contaminate storage area via leaks and&#xA;spills. Such waste would need to be thickened so it contained 35&#xA;percent solids.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;If high level nuclear waste is to be stored, the amount of heat&#xA;generated would be 1 - 3 Btu/h per US gallon (278.7 - 836.1 J/L). An&#xA;acre-foot (1233.48 m&lt;sup&gt;3&lt;/sup&gt;) of such waste would produce 1 MBtu&#xA;per hour (1055 MJ per hour). The equivalent of burning 700 lb (317.5&#xA;kg) of coal.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2022-07-14T16:44:54.400" LastActivityDate="2022-07-14T16:44:54.400" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24017" PostTypeId="2" ParentId="24015" CreationDate="2022-07-14T13:42:45.450" Score="1" Body="&lt;p&gt;If the picture was taken in the early morning, with sun rising in the east the picture was taken from the south. If if was taken late in day, with the sun setting in the west, the picture was taken from the north.&lt;/p&gt;&#xA;&lt;p&gt;During the normal course of the day, with the location in Canada, the location is well above the Tropic of Cancer, so the Sun is always in the southern part of the sky. If the right side of the buildings was illuminated the person taking the picture was to the west of the buildings.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-07-14T13:42:45.450" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24018" PostTypeId="1" AcceptedAnswerId="24021" CreationDate="2022-07-14T14:03:04.550" Score="1" ViewCount="116" Body="&lt;p&gt;My son reasoned that if the sun is shining on the right sides of the skyscrapers, then east is to the right. Therefore, the camera is facing north.&#xA;Therefore my son answered &amp;quot;a) North&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;But Scantron marked him wrong. Why? What's wrong with his deduction?  Please show the steps?&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;Unlike &lt;a href=&quot;https://earthscience.stackexchange.com/q/24015&quot;&gt;the previous question 1&lt;/a&gt;, this time a different picture features two different skyscrapers. &lt;em&gt;&lt;strong&gt;But now you have no clue or idea where, or in what hemisphere, this picture was taken.&lt;/strong&gt;&lt;/em&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Just like before, you can clearly see sunlight coming from the right hand side of the picture,  gleaming &lt;strong&gt;just&lt;/strong&gt; the right side of the skyscrapers. No sunlight whatsoever glistens their left side. What direction must the camera been facing?&lt;/p&gt;&#xA;&lt;p&gt;a) North&lt;br /&gt;&#xA;b) South&lt;br /&gt;&#xA;c) East&lt;br /&gt;&#xA;d) West&lt;br /&gt;&#xA;e) More information is needed to answer this question.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user17042" LastEditorDisplayName="user17042" LastEditDate="2022-07-14T15:28:25.143" LastActivityDate="2022-07-14T16:33:08.733" Title="In a picture taken in an unknown location, the sun shines on skyscrapers solely from the right. What direction was the camera facing?" Tags="|sun|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24019" PostTypeId="1" CreationDate="2022-07-14T15:14:46.377" Score="1" ViewCount="42" Body="&lt;p&gt;Google Earth doesn't show the ice sheets of the North Pole, but the undersea depth. How was this depth measured, when most of this area is covered by ice all year round?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pTkdQ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pTkdQ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27177" LastActivityDate="2022-07-14T15:14:46.377" Title="How was the sea depth under the North Pole ice sheets measured?" Tags="|geography|measurements|ice-sheets|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24020" PostTypeId="1" CreationDate="2022-07-14T15:46:26.730" Score="1" ViewCount="48" Body="&lt;p&gt;I'm trying to run hydus 1D so that I can do a sensitivity analysis of the solute transport parameters. I've scripted a matlab code to generate the files for each MC run.  I can't get hydrus to run beyond the first path{i}.  I've been working through this with the matlab forum folks to no avail and now I'm thinking maybe it's something with hydrus? I believe I have all the input files needed for each iteration in each subfile, even including the .exe. but I can't get hydrus to execute in all the other path{i} .  Any help welcome.  Code below:&lt;/p&gt;&#xA;&lt;p&gt;clear all;&#xA;clc;&#xA;%Solute transport parameters in row 47 of SELECTOR.IN file&#xA;SolTrans=[0.035 0 1 0.0479 0 0 0 0 273895 1 0 0 0 0]; %[Kd Nu Beta Henry SnkL1 SnkS1 SnkG1 SnkL1p SnkS1p SnkG1p SnkL10 SnkS10 SnkG10 Alfa] !! UPDATE NUMBERS IN BRACKETS !!&lt;/p&gt;&#xA;&lt;p&gt;%~~~~~~&#xA;%ADD NOISE TO SOLUTE TRANSPORT PARAMETERS&#xA;num_sim=100;    %100 Monte Carlo Simulations&#xA;Kd=SolTrans(1)+.02&lt;em&gt;rand(1,num_sim); %a vector with 100 values of Kd parameters. We assume that the error is normally distributed with a standard deviation of ##.&#xA;Nu=SolTrans(2)+.02&lt;/em&gt;rand(1,num_sim);&#xA;Beta=SolTrans(3)+.02&lt;em&gt;rand(1,num_sim);      %!!! CHANGE .02 FOR ALL THESE TO APPROPRIATE STANDARD DEVIATIONSN !!!&#xA;Henry=SolTrans(4)+.02&lt;/em&gt;rand(1,num_sim);&#xA;SnkL1=SolTrans(5);&#xA;SnkS1=SolTrans(6);&#xA;SnkG1=SolTrans(7);&#xA;SnkL1p=SolTrans(8);&#xA;SnkS1p=SolTrans(9)+.02*rand(1,num_sim);      %!!! FOR AWI MODIFIED MODEL - KL - LANGMUIR EXPONENT FOR AWI FOR LANGMUIR SORPTION or 0 FOR FREUNDLICH SORPTION&#xA;SnkG1p=SolTrans(10);&#xA;SnkL10=SolTrans(11);&#xA;SnkS10=SolTrans(12);&#xA;SnkG10=SolTrans(13);&#xA;Alfa=SolTrans(14);&lt;/p&gt;&#xA;&lt;p&gt;%~~~~~~&#xA;%INITIALIZE FILES AND DIRECTORIES&lt;/p&gt;&#xA;&lt;p&gt;hydrus_exec='C:\Users\jessi\Desktop\Hydrus\Projects\ATSDR\AFFF1PFOS\H1D_CALC.exe';   %'C:\Program Files (x86)\PC-Progress\Hydrus-1D 4\H1D_calc.exe';&lt;br /&gt;&#xA;hydrus_ref='C:\Users\jessi\Desktop\Hydrus\Projects\ATSDR\AFFF1PFOS';&lt;br /&gt;&#xA;profileDAT='C:\Users\jessi\Desktop\Hydrus\Projects\ATSDR\AFFF1PFOS\PROFILE.DAT';&lt;br /&gt;&#xA;options='C:\Users\jessi\Desktop\Hydrus\Projects\ATSDR\AFFF1PFOS\OPTIONS.IN';&#xA;atmosph='C:\Users\jessi\Desktop\Hydrus\Projects\ATSDR\AFFF1PFOS\ATMOSPH.IN';&#xA;selectorIN='C:\Users\jessi\Desktop\Hydrus\Projects\ATSDR\AFFF1PFOS\SELECTOR.IN';&lt;br /&gt;&#xA;level='C:\Users\jessi\Desktop\Hydrus\Projects\ATSDR\AFFF1PFOS\LEVEL_01.dir';&#xA;work_dir='C:\Users\jessi\Desktop\Simulations';&#xA;mkdir(work_dir);&lt;/p&gt;&#xA;&lt;p&gt;%~~~~~~&#xA;%CREATE DIRECTORIES AND INPUT FILES - This block is doing the work. Creates the input files for all realizations. Copies the mandatory file Profile.dat to&#xA;% the corresponding folder and creates the corresponding Selector&#xA;% .in. The Selector.in file is different for each realization since the solute transport parameters is&#xA;% variable. The code reads the reference Selector.in, copies the first 46 lines to the new file, write the van Genuchten parameters to the 47th line,&#xA;% and finally copies the last 10 lines from the reference Selector.in to the new file.&lt;/p&gt;&#xA;&lt;p&gt;path=cell(1,num_sim);&#xA;for i=1:num_sim&#xA;path{i}=strcat(work_dir,'run_',num2str(i)); %create folder for each run&lt;br /&gt;&#xA;mkdir(path{i});&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;copyfile(profileDAT,path{i}); %copy profileDAt from reference directory to the simulation directory &#xA;copyfile(options,path{i}); %copy options from reference directory to the simulation directory &#xA;copyfile(atmosph,path{i}); %copy atmosph from reference directory to the simulation director&#xA;copyfile(hydrus_exec,path{i}); %copy options from reference directory to the simulation directory &#xA;&#xA;%create a new level_01.dir in each subdirectory with associated file&#xA;%directory path&#xA;fid_level = fopen(fullfile(path{i},'LEVEL_01.dir'),'w');&#xA;fprintf(fid_level,'%s',path{i});&#xA;fclose(fid_level);&#xA;&#xA;&#xA;fileID_out=fopen(strcat(path{i},'\selector.in'),'wt'); %manipulate Selector.in for each run&#xA;                    % &amp;quot;wt&amp;quot;= permision for file axis type&#xA;                    % w=Open or create new file for writing. Discard existing contents, if any.&#xA;                   % To open files in text mode, attach the letter 't' to the permission argument,&#xA;fileID_in=fopen(selectorIN);&#xA;skip_lines=46;      %!!! THIS IS THE LINE THAT CHANGES IN SELECTOR.IN FILE , i.e. solute transport parameters!!!&#xA;for k=1:(skip_lines)&#xA;    x=fgetl(fileID_in); %x = fgetl(fileID)= returns the next line of the specified file, removing the newline characters.&#xA;    fprintf(fileID_out,'%s\n',x);  % %s in the formatSpec input indicates that the values of the variables url and sitename, should be printed as text. &#xA;                                   % '\n' as a newline indicator.   &#xA;                                   % &amp;quot;x&amp;quot; = prints the values from variable x&#xA;end&#xA;&#xA;out_Sol=SolTrans; % Renaming...&#xA;&#xA;%Whatever the solute transport parameter is for that monte carlo run (i)&#xA;out_Sol(1)=Kd(i);       % Solid phase sorption Kd&#xA;out_Sol(2)=Nu(i);       % Van Genuchten parameter&#xA;out_Sol(3)=Beta(i);     % Van Genuchten parameter&#xA;out_Sol(4)=Henry(i);     % Kh = KL*Rmax&#xA;out_Sol(9)=SnkS1p(i);    % KL - LANGMUIR EXPONENT FOR AWI FOR LANGMUIR SORPTION or 0 FOR FREUNDLICH SORPTION&#xA;&#xA;fprintf(fileID_out,'%f %f %f %f %f %f %f %f %f %f %f %f %f %f\n',out_Sol'); &#xA;                         % %f = Fixed-point notation (Use a precision operator to specify the number of digits after the decimal point.)&#xA;                         % '\n' as a newline indicator. &#xA;fgetl(fileID_in);        % returns the next line of the specified file, removing the newline characters.&#xA;skip_lines_end=5;       % CORRECT NUMBER???  DOUBLE CHECK&#xA;for k=1:(skip_lines_end)&#xA;    x=fgetl(fileID_in);&#xA;    fprintf(fileID_out,'%s\n',x);&#xA;end&#xA;fclose('all');&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;end&lt;/p&gt;&#xA;&lt;p&gt;for i=1:num_sim&#xA;exec_path=['&amp;quot;' fullfile(path{i},'H1D_CALC.exe') '&amp;quot; &amp;quot;' path{i} '&amp;quot;'];&#xA;[x, y]= dos(exec_path);&#xA;if x % unsuccessful&#xA;error('exe failed'); % or take some other action besides throwing an error&#xA;end&#xA;end&lt;/p&gt;&#xA;" OwnerUserId="27186" LastActivityDate="2022-07-14T15:46:26.730" Title="Trying to run a monte carlo of hydrus 1D" Tags="|matlab|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24021" PostTypeId="2" ParentId="24018" CreationDate="2022-07-14T16:33:08.733" Score="2" Body="&lt;p&gt;Your son was assuming that it is morning and therefore the Sun is to the east. That assumption is not valid. The Sun also shines in the evening when the Sun is to the west. In order for the Sun to be to the right in the evening, you must be facing south. Answer a) is not correct. Only answer &amp;quot;e) More information is needed to answer this question&amp;quot; is correct. The time of day is important to know.&lt;/p&gt;&#xA;&lt;p&gt;If it is noon, the hemisphere can be important. Buildings north of the Tropic of Cancer are illuminated on the south face (so camera facing east), and building south of the Tropic of Capricorn are illuminated on the north face (so camera facing west).&lt;/p&gt;&#xA;" OwnerUserId="19137" LastActivityDate="2022-07-14T16:33:08.733" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24022" PostTypeId="1" CreationDate="2022-07-14T23:31:40.457" Score="5" ViewCount="77" Body="&lt;p&gt;I asked this in the physics exchange and thought I would ask here as well:&lt;/p&gt;&#xA;&lt;p&gt;I see many sources in atmospheric dynamics express the following:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\frac{1}{\rho}(\nabla p) = \nabla_p \phi$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;For example &lt;a href=&quot;https://pog.mit.edu/src/810/pressure_coordinates.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this source&lt;/a&gt; equation 10.&lt;/p&gt;&#xA;&lt;p&gt;The reasoning given is that &lt;span class=&quot;math-container&quot;&gt;$\frac{1}{\rho}(\frac{\partial p}{\partial x})_z = (\frac{\partial \phi}{\partial x})_p$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\frac{1}{\rho}(\frac{\partial p}{\partial y})_z = (\frac{\partial \phi}{\partial y})_p$&lt;/span&gt;. (see equation 9 in my linked pdf).&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;While I agree with the above, shouldn't &lt;span class=&quot;math-container&quot;&gt;$\nabla_p \phi$&lt;/span&gt; lie in a different plane than the &lt;span class=&quot;math-container&quot;&gt;$\nabla p$&lt;/span&gt;? The first should lie in the plane &lt;span class=&quot;math-container&quot;&gt;$p=const$&lt;/span&gt; and the second should lie in the plane &lt;span class=&quot;math-container&quot;&gt;$z=const$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Informally the &lt;span class=&quot;math-container&quot;&gt;$i$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$j$&lt;/span&gt; unit vectors should be different for these two gradients since we are in different coordinate systems. While I agree that the magnitudes attached to these gradients is indeed the same, the would be a bit tilted from each other?&lt;/p&gt;&#xA;&lt;p&gt;I'm probably just missing something, and would appreciate some clarity, thank you.&lt;/p&gt;&#xA;" OwnerUserId="16818" LastEditorUserId="16818" LastEditDate="2022-07-15T10:01:42.530" LastActivityDate="2022-07-15T10:01:42.530" Title="Confusion about the horizontal pressure gradient force being equal to the gradient of the geopotential in pressure coordinates" Tags="|meteorology|atmosphere|coordinate-system|dynamics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24023" PostTypeId="1" CreationDate="2022-07-15T01:28:23.637" Score="5" ViewCount="345" Body="&lt;p&gt;I previously believed that continental crust owes its lower density to the partial melting of oceanic crust; the mantle would partially melt at mid-ocean ridges to produce basaltic crust, and when this oceanic crust eventually subducted, the basalt would then partially melt to produce an even lighter magma. This lighter magma would rise up and eventually erupt, building up a less dense continental crust above.&lt;/p&gt;&#xA;&lt;p&gt;However, I have recently learned that the magma produced at subduction zones comes from the partial melting of the mantle above the subducting plate and that very little comes from the plate itself. This means that mid-ocean ridges, hot spots, and subduction zones all derive their magma directly from the mantle, yet they somehow produce magmas of differing compositions.&lt;/p&gt;&#xA;&lt;p&gt;I have seen &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/4/48/Gesteinskreislauf_plus_2019.png&quot; rel=&quot;noreferrer&quot;&gt;explanations&lt;/a&gt; which state that felsic magma forms due to fractional crystallization of magma while working its way through the thick continental crust, but this still wouldn't explain how it forms under thin oceanic crusts at island arcs.&lt;/p&gt;&#xA;&lt;p&gt;I am trying to understand how a hot spot under oceanic crust produces shield volcanoes with basaltic rock while oceanic-oceanic subduction zones produce stratovolcanoes with felsic rock.&lt;/p&gt;&#xA;" OwnerUserId="27188" LastEditorDisplayName="user28185" LastEditDate="2023-01-08T19:42:53.680" LastActivityDate="2023-03-15T09:20:00.913" Title="How is felsic magma produced at island arcs?" Tags="|plate-tectonics|petrology|subduction|volcanic-eruption|oceanic-crust|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24024" PostTypeId="2" ParentId="24013" CreationDate="2022-07-15T08:13:27.113" Score="6" Body="&lt;p&gt;The footage turns blue because the camera adjusts its settings to the darker part. It probably raised the ISO and/or the exposure time to capture more light. This results in a brighter picture. This is also visible in the lower parts of the image. They turn very bright.&lt;/p&gt;&#xA;&lt;p&gt;I guess the camera captures quite a good impression on how dark the upper parts of the atmosphere are. There is almost nothing left that can scatter the light and this results in very dark conditions.&lt;/p&gt;&#xA;" OwnerUserId="26870" LastActivityDate="2022-07-15T08:13:27.113" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24025" PostTypeId="1" CreationDate="2022-07-15T17:00:22.583" Score="2" ViewCount="128" Body="&lt;p&gt;These photos were taken this week in the Tarragona province of Spain which is also seeing a heat wave at the moment. One can also see farmers using cultivators removing what were wild weeds that grew in between trees. So it seems to me like a common practice to keep the soil bare (at least this time of the year).&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/0xrbD.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/V8zsF.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;My layman understanding is that it is better to not leave soil bare to avoid erosion and evaporation (among other reasons).&#xA;What are the benefits of keeping the soil bare?&lt;/p&gt;&#xA;" OwnerUserId="27192" LastActivityDate="2022-07-15T23:34:44.110" Title="Why is the soil between these olive trees left bare?" Tags="|soil|agriculture|soil-moisture|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24026" PostTypeId="1" CreationDate="2022-07-15T17:06:09.737" Score="1" ViewCount="98" Body="&lt;p&gt;Why do all longitudes experience the Midday sun?&#xA;Any other information related will do.&#xA;What is the Midday Sun?&#xA;Any other earth or planet-related information is required.&#xA;Thank you to those who have answered my question.&lt;/p&gt;&#xA;" OwnerUserId="27193" LastActivityDate="2022-07-15T17:18:55.877" Title="All longitudes experience the midday Sun. Why do all longituted experience the Midday sun?" Tags="|earth-rotation|sun|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24027" PostTypeId="2" ParentId="24026" CreationDate="2022-07-15T17:18:55.877" Score="2" Body="&lt;p&gt;Midday is when the sun is at the highest point in the sky for any given day. Some would sat directly overhead.&lt;/p&gt;&#xA;&lt;p&gt;The Earth is spheroidal in shape. As the Earth spins it presents a different line of longitude to the Sun so that with each passing moment a different line of longitude has the Sun shining directly on it. When this occurs it is midday for each line of longitude.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-07-15T17:18:55.877" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24028" PostTypeId="2" ParentId="24025" CreationDate="2022-07-15T17:29:01.870" Score="2" Body="&lt;p&gt;Bare soil is one of the worst things for erosion. Such soil contains no plant roots to help contain the soil and thus prevent erosion. Bare soil is also one of the worst things for water loss from soil. The parts of plants above the soil can provide shade to the soil, which thus reduces moisture evaporating from the soil. More exposed soil has greater moisture loss and greater chances of being eroded.&lt;/p&gt;&#xA;&lt;p&gt;As for the soil between the olive trees, the most likely explanation is that the farmer doesn't want anything competing with the olive trees.&lt;/p&gt;&#xA;&lt;p&gt;Even though weeds will reduce soil moisture loss they also draw soil moisture for themselves so they can live. This places them in direct competition with the olive trees for soil moisture and nutrients.&lt;/p&gt;&#xA;&lt;p&gt;The farmer derives income from the olive trees and not the weeds. So the farmer removes the weeds, resulting in bare soil between the trees.&lt;/p&gt;&#xA;&lt;p&gt;The other thing is, when it comes time to harvest the olives, it is easier to harvest them with bare soil than with weeds everywhere.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="6467" LastEditDate="2022-07-15T23:34:44.110" LastActivityDate="2022-07-15T23:34:44.110" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24029" PostTypeId="1" CreationDate="2022-07-15T17:53:48.617" Score="2" ViewCount="76" Body="&lt;p&gt;Do space launches warm or cool the surface temperature (admittedly, for a little bit)? &lt;a href=&quot;https://www.bbc.com/future/article/20220713-how-to-make-rocket-launches-less-polluting&quot; rel=&quot;nofollow noreferrer&quot;&gt;This&lt;/a&gt; BBC article presents it as an emerging climate problem but also says&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;If the amount of black carbon expelled into the atmosphere reach 30 gigagrams a year, or even 100, then there will be some &lt;strong&gt;cooling&lt;/strong&gt; of the surface of the planet under this black carbon umbrella.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So what's the whole debate all about then? Isn't it a good thing that it counteracts the warming effect to some degree?&lt;/p&gt;&#xA;" OwnerUserId="22632" LastActivityDate="2022-08-14T19:04:30.360" Title="What's the effect of space launches on climate?" Tags="|climate-change|atmosphere|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24031" PostTypeId="1" AcceptedAnswerId="24032" CreationDate="2022-07-16T09:18:56.577" Score="5" ViewCount="1215" Body="&lt;p&gt;I did asked this question the other day: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/24011/why-are-salt-domes-suitable-for-the-final-disposal-of-nuclear-waste&quot;&gt;Why are salt domes suitable for the final disposal of nuclear waste?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;@Weiss posted the following illustration as a part of the answer:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DaDnu.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DaDnu.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://antisocialnetwork-2labz.blogspot.com/2017/04/rock-salt-for-dummies-freelance-files_15.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://antisocialnetwork-2labz.blogspot.com/2017/04/rock-salt-for-dummies-freelance-files_15.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I wonder why there is oil on the sides of the salt dome and if it is being extracted?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-07-17T12:28:15.330" LastActivityDate="2022-07-17T12:28:15.330" Title="Why is there oil on the flanks of a salt dome?" Tags="|salinity|oil-reserves|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24032" PostTypeId="2" ParentId="24031" CreationDate="2022-07-16T09:23:50.640" Score="4" Body="&lt;p&gt;good observation! The very simple answer is the same as for nuclear waste. The protective anhydrite layer over the salt dome became denser over time more dense. Therefore, the oil rises from below but remains on the sides (comparable to opening a balloon under an umbrella).&lt;/p&gt;&#xA;&lt;p&gt;Whether this oil is being extracted: yes, salt domes are always being searched for in oil exploration, as they usually have oil on their flanks. A sad example is the exploration drilling at Lake Peigneur. In this example, a salt works was built in a salt dome. Oil exploration damaged the protective layer and the salt became wet. As a result, parts of the salt mine collapsed.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HWYSw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HWYSw.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.reddit.com/r/submechanophobia/comments/bc8qyp/diagram_of_the_lake_peigneur_disaster_check_out/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.reddit.com/r/submechanophobia/comments/bc8qyp/diagram_of_the_lake_peigneur_disaster_check_out/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-07-17T07:32:48.063" LastActivityDate="2022-07-17T07:32:48.063" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24033" PostTypeId="2" ParentId="24031" CreationDate="2022-07-16T22:45:26.630" Score="2" Body="&lt;p&gt;There are 2 main reasons that oil is found near salt domes:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The permeability of the salt is extremely low, meaning fluids can't flow through it, and&lt;/li&gt;&#xA;&lt;li&gt;The geometry of the salt dome is such that it can trap oil beneath it.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Oil and gas, being less dense than water, &amp;quot;wants&amp;quot; to migrate upward through the rock strata from the source rock (which is almost always shale) where it was generated.  Occasionally it will encounter geologic features, such as a salt dome, which trap it.  The hydrocarbons get trapped because they can't move downward, they can only move up.  They can't move downward because everything else around it (rock and water) has higher density.&lt;/p&gt;&#xA;&lt;p&gt;The other poster who alluded to the density of the anhydrite is sort of right, but for the wrong reason.  The salt has very low density (relatively) and thus it also wants to move upward through the rock strata, and as it moves upward it also expands due to there being less stress on it.  This gives it the geometry that it needs to form an effective trap for oil and gas.&lt;/p&gt;&#xA;&lt;p&gt;Conventional oil explorationists also look for anticlines (think upside down bowls), faults, and stratigraphic pinchouts which can also trap hydrocarbons.&lt;/p&gt;&#xA;" OwnerUserId="27198" LastActivityDate="2022-07-16T22:45:26.630" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24034" PostTypeId="1" CreationDate="2022-07-17T08:07:26.817" Score="1" ViewCount="42" Body="&lt;p&gt;Hi I am facing a problem at the moment. In a paper I want to name areas that have the same isotopy. For example, areas with the same air pressure are called isobars. So these areas should be called isoisotopes. Is it possible to simply introduce such a term? And if so, how should the name be defined?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2ttDI.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2ttDI.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-07-17T09:53:25.493" LastActivityDate="2022-07-17T09:53:25.493" Title="Naming a new phenomenon" Tags="|isotopic|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24035" PostTypeId="1" CreationDate="2022-07-17T13:20:32.133" Score="2" ViewCount="58" Body="&lt;p&gt;As argued in this Nature letter [1] by Matthews and Weaver, when we achieve net-zero emissions further warming will cease. The authors cite numerous models, and say that future emissions are a leading order factor in warming, due to the propensity for Earth's carbon sinks to start sucking up carbon. However as a Physicist it seems like an incorrect claim. The Earth's thermal system will remain out of equilibrium until a new equilibrium is reached, as the carbon cycle's time-scale is 10s of thousands of years, net-zero will change little in terms of a heated climate.&lt;/p&gt;&#xA;&lt;p&gt;Furthermore, even looking at a single one of their own references [2], one can see that the research into the long-livedness of atmospheric carbon, and the resulting temperature anomaly is of the order of tens of thousands of years, reflecting the large inertia of the Earth's climate system, in direct contradiction to the claims of [1]!&lt;/p&gt;&#xA;&lt;p&gt;So my question is, who is correct according to current research? Why was this published in a Nature journal, when its claims are misleading?&lt;/p&gt;&#xA;&lt;p&gt;And finally, I would appreciate anyone could direct me to any bleeding edge research on.&lt;/p&gt;&#xA;&lt;p&gt;[1] &lt;a href=&quot;https://www.nature.com/articles/ngeo813&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/ngeo813&lt;/a&gt;&#xA;[2] &lt;a href=&quot;https://journals.ametsoc.org/view/journals/clim/22/10/2008jcli2554.1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://journals.ametsoc.org/view/journals/clim/22/10/2008jcli2554.1.xml&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27203" LastActivityDate="2022-07-18T13:25:45.280" Title="If radiative forcing will remain the same when 'net-zero' is achieved, why do some experts think the climate will not warm after this?" Tags="|climate|carbon-cycle|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24036" PostTypeId="2" ParentId="23026" CreationDate="2022-07-17T16:16:32.310" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://es.wikipedia.org/wiki/Erupci%C3%B3n_volc%C3%A1nica_de_La_Palma_de_2021&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia spanish entry&lt;/a&gt; says 20th november the Volcanic Explosivity Index raised from 2 to 3.&lt;/p&gt;&#xA;&lt;p&gt;The reason is Canary Islands Volcanic Emergencies Plan (PEVOLCA) considered that the 20th november the emission of pyroclasts exceded 10 million cubic meters.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The volcano of La Palma, which erupted 61 days ago in Cumbre Vieja, has exceeded the emission of 10 million cubic meters of pyroclasts, for which the scientific committee of the Canary Islands Volcanic Emergencies Plan (Pevolca) has raised its rate of explosiveness from 2 to 3, on a scale of 8.&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.lainformacion.com/espana/el-volcan-de-la-palma-sube-su-indice-de-explosividad-por-emision-de-piroclastos/2853935/&quot; rel=&quot;nofollow noreferrer&quot;&gt;lainformacion.com&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I guess there was a mistake in &lt;a href=&quot;https://en.wikipedia.org/wiki/2021_Cumbre_Vieja_volcanic_eruption&quot; rel=&quot;nofollow noreferrer&quot;&gt;english wikipedia entry&lt;/a&gt; when you posted the question as now it can be read:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;For its first two months, the eruption was assigned a rating on the Volcanic Explosivity Index (VEI) of VEI 2 (on a scale of 8). &lt;strong&gt;On 20 November 2021, the scientific committee of the Canary Islands Volcanic Emergency Plan (Pevolca) raised the rating from VEI 2 to VEI 3&lt;/strong&gt;. Though in modern eruptions where it can be measured, eruption column height is often seen as a more accurate measure, in this case the change was based on the 10 million cubic metres of ejected material measure alone. The VEI rating was increased despite no change in the eruptive mechanism or explosiveness.&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/2021_Cumbre_Vieja_volcanic_eruption&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerDisplayName="user27204" LastEditorDisplayName="user27204" LastEditDate="2022-07-17T16:40:39.220" LastActivityDate="2022-07-17T16:40:39.220" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24037" PostTypeId="2" ParentId="23860" CreationDate="2022-07-17T17:03:22.643" Score="1" Body="&lt;p&gt;There are several types of rocks in San Gabriel mountain:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Geology of the San Gabriel Mountains is mostly Mesozoic (65 to 245&#xA;million years ago) granitic rocks, but there are also Precambrian (544&#xA;to 4,600 million years ago) igneous and metamorphic rock complexes.&#xA;There are also occasional Pleistocene (57.8 to 65 million years ago)&#xA;nonmarine sedimentary deposits adjacent to the riverbed.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://ladpw.org/wmd/watershed/sg/mp/docs/eir/04.04-Geology.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Your first picture migth well be a Mesozoic granite, but also a Precambrian metamorphic granitoid.&lt;/p&gt;&#xA;&lt;p&gt;The second one shows foliation, so it is a Precambrian metamorphic rock. Imposible to precise more with the picture.&lt;/p&gt;&#xA;&lt;p&gt;From the third and fourth it is impossible to know what they are from a picture. They migth be Pleistocene nonmarine sedimentary deposits.&lt;/p&gt;&#xA;&lt;p&gt;You migth wish to read some of the &lt;a href=&quot;https://www.usgs.gov/search?keywords=san%20gabriel%20mountains&quot; rel=&quot;nofollow noreferrer&quot;&gt;publications USGS published about the zone&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;You have some more info about the geology of the zone &lt;a href=&quot;http://www.csun.edu/science/geoscience/fieldtrips/san-gabriel-mts/geology-san-gabriels.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user27204" LastEditorDisplayName="user27204" LastEditDate="2022-07-17T17:19:01.030" LastActivityDate="2022-07-17T17:19:01.030" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24038" PostTypeId="1" CreationDate="2022-07-17T21:49:30.140" Score="1" ViewCount="148" Body="&lt;p&gt;I recently found a calculation on how to calculate the greenhouse effect for Earth from another question here, but I couldn't make heads or tails of the calculations that were provided in one of the answers.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/12093/how-can-we-calculate-the-temperature-of-the-atmosphere-including-the-greenhouse&quot;&gt;How can we calculate the temperature of the atmosphere, including the greenhouse effect?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Would it be possible for someone to explain the calculation structure and how to use it for exoplanets (worldbuilding exercise) like I'm five? I have no problem replicating the calculations once I know how to do it, but I just need to know what figures and units I need to use for the process.&lt;/p&gt;&#xA;&lt;p&gt;At present, I know how to get the surface temperature for a planet without an atmosphere, so I just need help getting the calculation for a planet with an atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="27205" LastEditorUserId="27205" LastEditDate="2022-07-18T02:22:55.067" LastActivityDate="2022-07-18T02:22:55.067" Title="How to calculate greenhouse effect for planet as well as for the atmosphere?" Tags="|atmosphere|temperature|greenhouse-gases|sun|solar-terrestrial-physics|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24040" PostTypeId="1" AcceptedAnswerId="24049" CreationDate="2022-07-18T08:56:36.917" Score="20" ViewCount="6842" Body="&lt;p&gt;I've been playing &lt;a href=&quot;https://worldle.teuteuf.fr/&quot; rel=&quot;noreferrer&quot;&gt;Worldle&lt;/a&gt; for a while, and noticed that colder countries seem to have more rugged coasts. See Svalbard for example:&lt;/p&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/kyx1n.png&quot; width=&quot;300&quot;&gt;&#xA;&lt;p&gt;And Patagonia:&lt;/p&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/I9z0x.jpg&quot; width=&quot;300&quot;&gt;&#xA;&lt;p&gt;Whereas e.g. Bali is smoother:&lt;/p&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/kwKYz.jpg&quot; width=&quot;300&quot;&gt;&#xA;&lt;p&gt;Does it have something to do with the ocean being stronger in colder climates and washing away more of the &amp;quot;softer&amp;quot; parts of the coast over time? That's just a layman's guess, I'm really not sure.&lt;/p&gt;&#xA;&lt;p&gt;Excited to learn about this if anyone knows the answer!&lt;/p&gt;&#xA;" OwnerUserId="27208" LastEditorUserId="27208" LastEditDate="2022-07-18T08:59:41.173" LastActivityDate="2022-07-19T16:55:58.767" Title="Why do colder climates have more rugged coasts?" Tags="|climate|coastal|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24041" PostTypeId="1" CreationDate="2022-07-18T10:33:29.220" Score="4" ViewCount="34" Body="&lt;p&gt;I've seen this question asked before and the answer was we don't know because of the poor fossil record.&lt;/p&gt;&#xA;&lt;p&gt;I'm unsatisfied with that as it seems that other means like sedimentation might be a starting point to get some idea. Furthermore, we have some idea of the productivity of Earth's land surface now and may have a reasonable idea of how much of the Earth's surface was productive in the Eocene for example.&lt;/p&gt;&#xA;&lt;p&gt;I've learned that 30% of the current Earth's land is &amp;quot;productive&amp;quot; which means as I remember 4kg of biomass per square meter. I'm speculating that perhaps 90% of the Earth's surface was &amp;quot;productive&amp;quot; during the Eocene. And making a presumptive guess that Earth's biodiversity was an order of magnitude higher during that time compared to today.&lt;/p&gt;&#xA;&lt;p&gt;The only reference I have found is the book by Donald R. Prothero titled &lt;a href=&quot;https://books.google.es/books/about/The_Eocene_Oligocene_Transition.html?id=yLyuI44SP28C&amp;amp;redir_esc=y&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Eocene-Oligocene Transition: Paradise Lost.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27209" LastEditorDisplayName="user27204" LastEditDate="2022-07-19T18:20:10.743" LastActivityDate="2022-07-19T18:20:10.743" Title="What is the size of Earth's biomass over time? How has it changed?" Tags="|earth-history|biomass|" AnswerCount="0" CommentCount="0" ClosedDate="2022-07-23T12:00:23.580" ContentLicense="CC BY-SA 4.0" />
  <row Id="24042" PostTypeId="2" ParentId="24040" CreationDate="2022-07-18T12:18:43.140" Score="23" Body="&lt;p&gt;Have you had a look at the northern coast of Russia or Alaska, in the cold Arctic? Having just looked at them on Google Earth, they are lengthy and seem very &amp;quot;un-rugged&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;The northern coast of Russia:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tRKxq.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tRKxq.jpg&quot; alt=&quot;Russia&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The northern coast of Alaska:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/d6zOH.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/d6zOH.jpg&quot; alt=&quot;Alaska&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Opposite of that, in the hot subtropical Australia, the Kimberley coast in the north western part of the continent looks rugged:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Wp7It.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Wp7It.jpg&quot; alt=&quot;Kimberley Australia&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2k7dX.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2k7dX.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;There's also the countries of the Aegean Sea, which have a very Mediterranean climate.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fXHpJ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fXHpJ.jpg&quot; alt=&quot;Aegean Sea&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;And there are also parts of the coasts of Myanmar, The Philippines, Indonesia and Fjordland in New Zealand which could be considered rugged.&lt;/p&gt;&#xA;&lt;p&gt;To have a rugged coastline the coastline needs to be composed of rocky terrain, with valleys, gullies, canyons or mountains, that erodes slowly.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="6298" LastEditDate="2022-07-18T16:08:05.140" LastActivityDate="2022-07-18T16:08:05.140" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24043" PostTypeId="2" ParentId="24035" CreationDate="2022-07-18T13:25:45.280" Score="1" Body="&lt;p&gt;You probably want to have a look at the more recent ZECMIP (zero emissions commitment) paper MacDougall et al (2020) &lt;a href=&quot;https://doi.org/10.5194/bg-17-2987-2020&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.5194/bg-17-2987-2020&lt;/a&gt;, along with the schematic on the right from the IPCC AR6 Technical Summary:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/UIOMz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UIOMz.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;That schematic suggests that the bulk of the warming since the pre-industrial period will come while we have net-positive emissions and that the post-net zero emissions committed warming will be some small addition on top of this.&lt;/p&gt;&#xA;&lt;p&gt;To understand this we need to think about the net radiative imbalance (currently +0.6 W/m2) rather than the radiative forcing (currently +2.2 W/m2).  That imbalance is the net result of the radiative forcing and the various feedbacks, some of which are negative feedbacks (e.g., the Planck response, land and ocean carbon uptake).  The Planck response to surface temperature is about -3 W/m2/K, so, once net-zero emissions are achieved, the surface would only need to warm by a further 0.2 K to erode the 0.6 W/m2 radiative imbalance through this mechanism alone.&lt;/p&gt;&#xA;&lt;p&gt;But there are other feedbacks in play.  Once net-zero emissions are reached the existing land and ocean carbon sinks will continue to take up CO2, so atmospheric CO2 will decrease and its contribution to radiative forcing and radiative imbalance will decrease.  This reduces the amount of work the Planck response has to do to achieve radiative balance.  The faster the carbon sinks work, the less additional warming will be needed to before radiative balance is achieved.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, ocean heat uptake will likely weaken once net-zero emissions are reached, because the current ocean heat sink is partly driven by the ocean-atmosphere temperature gradient.  This effectively becomes a positive feedback on surface temperature change.  Going back to MacDougall et al (2020), it turns out that these feedbacks are strong and the zero emissions committed surface warming is a subtle balance between these components, giving a best estimate range of -0.3 to +0.3 K (see plots below).&lt;/p&gt;&#xA;&lt;p&gt;A key thing here it that this is a measure of the atmospheric response, which doesn't have a great deal of thermal inertia.  The ocean is still out of balance and accumulating heat, and the carbon cycle is still out of balance removing CO2 from the atmosphere.  Equilibration of other components of the Earth system would take much longer, as you say, but that's not the goal of net-zero.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zvdhE.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zvdhE.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2022-07-18T13:25:45.280" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24044" PostTypeId="1" CreationDate="2022-07-18T16:15:21.900" Score="2" ViewCount="40" Body="&lt;p&gt;Ekman transport components are in the zonal and meridional direction.&#xA;Along the coast of California, which is an eastern boundary coast, say there is wind flowing down the coast in the meridional direction (towards the equator).&#xA;The zonal Ekman component would be pointed towards the right of that wind vector causing water along that boundary to move offshore (so away from the coast), right?&lt;/p&gt;&#xA;&lt;p&gt;But what is the relationship between the magnitude of Ekman transport (both components), zonal or meridional Ekman transport with the volume transport say taken along a cross section at one latitude along the California coast?&lt;/p&gt;&#xA;&lt;p&gt;Basically how is the volume transport and Ekman transport (zonal, meridional, or magnitude) related?&#xA;Thank you and let me know if the question needs to be elaborated!&lt;/p&gt;&#xA;" OwnerUserId="27210" LastActivityDate="2022-07-18T16:15:21.900" Title="What is the relationship between Ekman transport and volume transport?" Tags="|oceanography|ocean-currents|ocean-models|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24046" PostTypeId="2" ParentId="4600" CreationDate="2022-07-19T01:21:06.997" Score="0" Body="&lt;p&gt;The global mean SST is 16.1 °C (60.9 °F) while the global mean surface air temperature is 14°C (57°F) so the net heat flux is from the ocean to the air. Since the surface air temperature has been rising faster than the sea surface temperature the rate of heat flux from ocean to air has decreased.  Since the sun continues to heat the oceans at the same rate then the total heat in the oceans increases.&lt;/p&gt;&#xA;" OwnerUserId="27212" LastActivityDate="2022-07-19T01:21:06.997" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24047" PostTypeId="1" CreationDate="2022-07-19T08:12:41.427" Score="2" ViewCount="39" Body="&lt;p&gt;The International and U.S. Standard atmospheres have a layer between 11 km (36,000 ft) and 20 km (66,000 ft) where the temperature is constant with altitude. This includes older versions of the U.S. Standard atmosphere. However, sometimes I come across temperature models that maintain the temperature constant up to 25 km (82,000 ft) and begin an increase in temperature above that altitude. What models are these and why are they different from the (usual) standard atmospheres?&lt;/p&gt;&#xA;" OwnerUserId="27157" LastEditorUserId="27157" LastEditDate="2022-07-19T14:06:19.537" LastActivityDate="2022-07-19T14:06:19.537" Title="Which atmosphere model(s) put the upper end of the tropopause isothermal layer at 25 km and why?" Tags="|temperature|atmosphere-modelling|troposphere|stratosphere|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24048" PostTypeId="1" CreationDate="2022-07-19T11:27:09.233" Score="8" ViewCount="81" Body="&lt;p&gt;I am considering buying a set of Mohs hardness scratch pens (aka hardness picks). As a hobbyist the price is quite high, starting at 300 USD and upwards for a complete set. I can accept this price if I can expect them to do their job for a lifetime, or at least for a decade.&lt;/p&gt;&#xA;&lt;p&gt;I assume that the tip of these picks are machined to have a sharp edge, probably a single point.&lt;/p&gt;&#xA;&lt;p&gt;All cutting tools, like drill bits or saw tooths loose this sharp edge with use, so I assume the same will happen with these scratch pens. But when googling for this, I havent found a single source that talks about how to maintain/sharpen these pens, and I haven't found a single source that talks about how long they last or if they will need replacing.&lt;/p&gt;&#xA;&lt;p&gt;So let me try and put this into a few questions:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;How long can I expect such a pen to last and how long will it do its job well?&lt;/li&gt;&#xA;&lt;li&gt;Do people sharpen or otherwise maintain their scratch pens?&lt;/li&gt;&#xA;&lt;li&gt;Do people replace their scratch pens?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="27216" LastActivityDate="2023-03-21T19:38:29.983" Title="Will a Mohs hardness scratch pen need to be replaced or resharpened?" Tags="|geology|field-measurements|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24049" PostTypeId="2" ParentId="24040" CreationDate="2022-07-19T16:47:51.197" Score="23" Body="&lt;p&gt;As Fred's answer and some comments wrote, this is of course not so generally true.&lt;/p&gt;&#xA;&lt;p&gt;What &lt;em&gt;is&lt;/em&gt; true is that many rough coasts were formed by past glaciation. Obviously you don't tend to get many glaciers near sea level in tropical regions, so that's part of the answer!&lt;/p&gt;&#xA;&lt;p&gt;But it's not only about temperature. A more precise statement is: &lt;strong&gt;Cold, humid winters cause rough coastlines&lt;/strong&gt;. Why? because the rapid accumulation of snow and then ice causes thick glaciers that flow relatively fast, even without much initial elevation. And flowing glaciers are mighty roughness-shapers, both by eroding high ground and carving out fjords, as well as piling up moraines. Scandinavia is a prime example: lots of humid atlantic air snows down over Norway, where the glaciers have carved out all those fjords. In the past they also reached over Sweden, where the coast is by no means mountainous but nevertheless quite rough, because the leftover moraines funneled more recent water erosion into irregular shapes.&lt;/p&gt;&#xA;&lt;p&gt;By contrast, cold climates with less snowfall (e.g. Antarctica) rather glaciate slowly in flat sheets that steadily drift into the sea, and don't cause the above features as much.&lt;/p&gt;&#xA;&lt;p&gt;And of course rough coasts can also be formed my mechanisms unrelated to glaciation, such as volcanism and particular kinds of stratigraphy, which may be found in warm climates.&lt;/p&gt;&#xA;" OwnerUserId="12095" LastEditorUserId="12095" LastEditDate="2022-07-19T16:55:58.767" LastActivityDate="2022-07-19T16:55:58.767" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24050" PostTypeId="1" CreationDate="2022-07-20T05:08:20.390" Score="2" ViewCount="330" Body="&lt;p&gt;I basically want to make this same idea:&#xA;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/16366/weather-forecast-based-on-pressure-temperature-and-humidity-only-for-implement#new-answer?newreg=e19b15ff8fa94b949b47b2aa453465f9&quot;&gt;Weather forecast based on pressure, temperature and humidity only (for implementation in Arduino)&lt;/a&gt;&#xA;without the pressure sensor.&#xA;I have a DS18B20 and a HR202 to do it with, if it is possible.&lt;/p&gt;&#xA;" OwnerUserId="27223" LastEditorUserId="2470" LastEditDate="2022-07-20T13:16:57.890" LastActivityDate="2022-07-20T13:16:57.890" Title="Predicting the weather with temperature and humidity" Tags="|meteorology|weather-forecasting|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="24051" PostTypeId="1" AcceptedAnswerId="24087" CreationDate="2022-07-20T08:23:40.207" Score="3" ViewCount="109" Body="&lt;p&gt;1 Do ice core temperature reconstruction studies have a calibration step, or is the relationship between Oxygen-18 and mean global temperature considered linear enough that this is not required?&lt;/p&gt;&#xA;&lt;p&gt;2 Irrespective of whether calibration is used or not, do ice core reconstruction studies supply a verification statistic (R-square) against the instrumental temperature record?&lt;/p&gt;&#xA;&lt;p&gt;Please could you point me to any papers containing these statistics&lt;/p&gt;&#xA;" OwnerUserId="27110" LastEditorUserId="26841" LastEditDate="2022-08-16T19:15:45.513" LastActivityDate="2022-08-16T19:15:45.513" Title="Verification statistic for ice core temperature reconstructions" Tags="|paleoclimatology|isotopic|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24052" PostTypeId="1" AcceptedAnswerId="24062" CreationDate="2022-07-20T08:59:50.730" Score="10" ViewCount="8466" Body="&lt;p&gt;I just read the IPCC's Fourth Assessment Report and noticed that this is the first (or first very significant) report to state that climate change exists and can no longer be scientifically disproved. However, humankind has known since 1824, since the discovery of Jean-Baptiste Joseph Fourier, that greenhouse gases are changing the atmosphere. So I ask myself, why did it take so long to gain knowledge and what were the major theories that speak against human-made climate change?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-11-08T14:50:32.067" LastActivityDate="2022-11-08T14:50:32.067" Title="Why had climate change not been proven beyond doubt for so long?" Tags="|climate-change|earth-history|" AnswerCount="5" CommentCount="13" ContentLicense="CC BY-SA 4.0" />
  <row Id="24053" PostTypeId="1" CreationDate="2022-07-20T10:01:28.813" Score="6" ViewCount="998" Body="&lt;p&gt;Hi I just found the NOAA table. It clearly shows that the N. hemisphere has warmed much more than the southern hemisphere since 1880!&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xNu6V.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xNu6V.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.ncei.noaa.gov/access/monitoring/monthly-report/global/202113&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncei.noaa.gov/access/monitoring/monthly-report/global/202113&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;What could be the reason for this?&#xA;My idea is that the N. hemisphere has accumulated significantly more continental mass, while the S. hemisphere is almost continent-free. And the water is warming because the Gulf Stream is currently flushing more warm water northwards. Is my idea correct? Do you have other suggestions or are there suitable papers?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-09-12T07:35:59.550" LastActivityDate="2023-01-15T15:59:26.233" Title="Why is the Northern Hemisphere warming faster than the Southern Hemisphere?" Tags="|climate-change|atmosphere|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="24054" PostTypeId="1" CreationDate="2022-07-20T10:39:20.937" Score="3" ViewCount="57" Body="&lt;p&gt;I have seen that stratospheric aerosol injection could potentially be used to combat global warming. My question is whether it would be possible to e.g. inject aerosols at different rates in different places in order to adjust climate locally, or if it necessarily has global effects. I.e. would it be possible/feasiable to, for example, stop any climate warming completely in location A, but allow some moderate climate warming in location B.&lt;/p&gt;&#xA;" OwnerUserId="27227" LastActivityDate="2023-02-12T19:09:34.297" Title="Could stratospheric aerosol injection be used to fine-tune climate locally?" Tags="|geoengineering|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24055" PostTypeId="1" AcceptedAnswerId="24076" CreationDate="2022-07-20T10:59:58.603" Score="4" ViewCount="155" Body="&lt;p&gt;So, i found a weird structure in a piece of jurassic limestone. It is cylindrical and roughly one cm in diameter, enters the stone on one side and leaves on the other. Under the microscope, you can see particles of limestone/calcite at the inner walls, partially being held in place by some hair-like fibers. Is this a fossil, and if yes, what kind of animal or plant could this have been? Or is it something anorganic?&lt;/p&gt;&#xA;&lt;p&gt;I'm new here, please tell me if i forgot to mention anything important. Thanks in advance.&lt;/p&gt;&#xA;&lt;p&gt;Here are some pictures:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/4hHzH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4hHzH.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5Xp9A.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5Xp9A.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/1YC4j.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1YC4j.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27228" LastEditorUserId="27228" LastEditDate="2022-07-22T11:52:49.983" LastActivityDate="2022-07-23T13:05:34.267" Title="Is this a fossil or something anorganic?" Tags="|paleontology|fossils|paleobotany|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="24056" PostTypeId="2" ParentId="24052" CreationDate="2022-07-20T13:15:06.617" Score="15" Body="&lt;p&gt;Just because a &amp;quot;small number&amp;quot; of scientists knew about something in the mid 1820s doesn't mean it was initially accepted by other scientists. You also have to consider the means of disseminating information and knowledge then and since. You also have to consider what other attitudes prevailed.&lt;/p&gt;&#xA;&lt;p&gt;Charles Darwin's Theory of Evolution was vigorously opposed by many eminent people because of religious beliefs. In some places it still is.&lt;/p&gt;&#xA;&lt;p&gt;Personally, I first became aware of global warming via the mass media many years &lt;em&gt;after&lt;/em&gt; I completed my university studies. I was taught other scientific things - there's a lot to learn - and I still think I had a good education.&lt;/p&gt;&#xA;&lt;p&gt;I became aware of Darwin's Theory of Evolution in high school, but no-one mentioned global warming or the heat retaining potential of carbon dioxide or methane, or whatever else. It wasn't part of the science curriculum, other things were.&lt;/p&gt;&#xA;&lt;p&gt;People may have been warning about global warming before that, but from what I'm aware of they were few in number, they didn't captivate the attention of the mass media and they were essentially voices in the wilderness. There's a saying &amp;quot;the squeaky wheel gets the oil&amp;quot;, they weren't squeaky enough.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-07-20T13:15:06.617" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="24057" PostTypeId="1" CreationDate="2022-07-20T14:48:03.897" Score="3" ViewCount="66" Body="&lt;p&gt;The BBC ran an article &lt;a href=&quot;https://www.bbc.com/news/science-environment-58073295&quot; rel=&quot;nofollow noreferrer&quot;&gt;Extreme weather: What is it and how is it connected to climate change&lt;/a&gt; that contained this graphic:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://ichef.bbci.co.uk/news/976/cpsprodpb/16C59/production/_119737239_heat_dome_2x640-nc-2x-nc.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/om6dg.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Is this accurate? &lt;strong&gt;Does high pressure in the atmosphere push warm air down, which is then compressed and gets even hotter?&lt;/strong&gt; From basic knowledge it would seem that &amp;quot;high pressure in the atmosphere&amp;quot; would mean denser air, which would (possibly as bubbles?) displace the less-dense warm air, letting this less-dense warm air &amp;quot;float&amp;quot; on it (perhaps the warm air also moves up through the denser air as bubbles). Details of the lower-warm-air / higher-dense-air interface aside, what really happens? Does the denser air move down and the warmer air move up (as I believe) or does the denser air (called high pressure in the graphic) push the warm air down, as depicted in the graphic?&lt;/p&gt;&#xA;" OwnerUserId="222" LastActivityDate="2022-07-20T14:48:03.897" Title="Does high atmospheric pressure in the atmosphere push warm air down?" Tags="|atmosphere|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24060" PostTypeId="2" ParentId="24052" CreationDate="2022-07-20T20:15:03.143" Score="39" Body="&lt;p&gt;&amp;quot;Why has climate change not been proven beyond doubt for so long?&amp;quot; to a good degree has the same answer as &amp;quot;why has a connection between smoking and lung cancer not been proven beyond doubt for so long?&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Because there is a lot of money in return for prolonging the doubt.  It takes considerable effort establishing the structures cementing global enterprises, and change disrupts many people's livelihoods.&lt;/p&gt;&#xA;&lt;p&gt;So while there is some money to be made by paying scientists to advance the knowledge about some global phenomenon, sometimes paying scientists to corrupt knowledge has larger payoffs, with the actually incurred costs getting borne by society in general.&lt;/p&gt;&#xA;&lt;p&gt;And for politicians it tends to be a favorable deal to trail established scientists considerably with regard to recognizing the undeniable.  It's popular with both voters and lobbyists.&lt;/p&gt;&#xA;" OwnerDisplayName="user27236" LastEditorDisplayName="user27236" LastEditDate="2022-07-20T20:16:59.610" LastActivityDate="2022-07-20T20:16:59.610" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24061" PostTypeId="2" ParentId="24052" CreationDate="2022-07-20T20:38:39.183" Score="23" Body="&lt;p&gt;It's the first very significant report to make that claim because the claim is unscientific in nature.&lt;/p&gt;&#xA;&lt;p&gt;As &lt;a href=&quot;https://books.google.com/books?id=IOFmZoesMNoC&amp;amp;pg=PA1602&amp;amp;lpg=PA1602&amp;amp;dq=%22The%20scientific%20theorist%20is%20not%20to%20be%20envied.%20For%20Nature,%20or%20more%20precisely%20experiment,%20is%20an%20inexorable%20and%20not%20very%20friendly%20judge%20of%20his%20work.%20It%20never%20says%20%22Yes%22%20to%20a%20theory.%20In%20the%20most%20favorable%20cases%20it%20says%20%22Maybe,%22%20and%20in%20the%20great%20majority%20of%20cases%20simply%20%22No.%22%20If%20an%20experiment%20agrees%20with%20a%20theory%20it%20means%20for%20the%20latter%20%22Maybe,%22%20and%20if%20it%20does%20not%20agree%20it%20means%20%22No.%22%20Probably%20every%20theory%20will%20someday%20experience%20its%20%22No%22%E2%80%94most%20theories,%20soon%20after%20conception.%22&amp;amp;source=bl&amp;amp;ots=sVp_d0NO1L&amp;amp;sig=pIt5kjxteB_51khNld7sdaFqN-8&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=0ahUKEwiN79KTg9HXAhUrjFQKHQG7CHcQ6AEIKDAA#v=onepage&amp;amp;q=%22The%20scientific%20theorist%20is%20not%20to%20be%20envied.%20For%20Nature%2C%20or%20more%20precisely%20experiment%2C%20is%20an%20inexorable%20and%20not%20very%20friendly%20judge%20of%20his%20work.%20It%20never%20says%20%22Yes%22%20to%20a%20theory.%20In%20the%20most%20favorable%20cases%20it%20says%20%22Maybe%2C%22%20and%20in%20the%20great%20majority%20of%20cases%20simply%20%22No.%22%20If%20an%20experiment%20agrees%20with%20a%20theory%20it%20means%20for%20the%20latter%20%22Maybe%2C%22%20and%20if%20it%20does%20not%20agree%20it%20means%20%22No.%22%20Probably%20every%20theory%20will%20someday%20experience%20its%20%22No%22%E2%80%94most%20theories%2C%20soon%20after%20conception.%22&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;Albert Einstein once said&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The scientific theorist is not to be envied. For Nature, or more&#xA;precisely experiment, is an inexorable and not very friendly judge of&#xA;his work. It never says &amp;quot;Yes&amp;quot; to a theory. In the most favorable cases&#xA;it says &amp;quot;Maybe,&amp;quot; and in the great majority of cases simply &amp;quot;No.&amp;quot; If an&#xA;experiment agrees with a theory it means for the latter &amp;quot;Maybe,&amp;quot; and&#xA;if it does not agree it means &amp;quot;No.&amp;quot; Probably every theory will someday&#xA;experience its &amp;quot;No&amp;quot;—most theories, soon after conception.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Or, more recently, as &lt;a href=&quot;https://histsci.fas.harvard.edu/people/liv-grjebine&quot; rel=&quot;nofollow noreferrer&quot;&gt;Liz Gerjbine&lt;/a&gt; writes in &lt;a href=&quot;https://www.scientificamerican.com/article/why-doubt-is-essential-to-science/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scientific American&lt;/a&gt; &amp;quot;[S]cience cannot provide certainties.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;This isn't an attempt to cast doubt on climate change, in fact I think &lt;strong&gt;a better comparison would be saying we're about as certain as we are about gravity&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;So they're the first to publish that statement because a core tenet of science, if not &lt;em&gt;the&lt;/em&gt; core tenet, is &lt;em&gt;doubt&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I'm actually quite shocked any serious scientist or group would make the statement &amp;quot;can no longer be scientifically disproved&amp;quot; about anything. Seems more like political grandstanding than genuine science.&lt;/p&gt;&#xA;&lt;p&gt;The other answers so far do a fine job explaining the slow dissemination and acceptance of scientific findings.&lt;/p&gt;&#xA;" OwnerUserId="21388" LastEditorUserId="21388" LastEditDate="2022-07-24T14:03:32.160" LastActivityDate="2022-07-24T14:03:32.160" CommentCount="22" ContentLicense="CC BY-SA 4.0" />
  <row Id="24062" PostTypeId="2" ParentId="24052" CreationDate="2022-07-20T23:20:40.403" Score="17" Body="&lt;p&gt;&lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/02/ar4-wg1-chapter9-1.pdf&quot; rel=&quot;noreferrer&quot;&gt;Chapter 9&lt;/a&gt; of the Fourth Assessment Report gives a comprehensive overview of the difficulties involved in 'detection and attribution'. It is worth reading in detail - it gives a much better idea of the complexity and residual uncertainties of the conclusions than the newspaper headlines do.&lt;/p&gt;&#xA;&lt;p&gt;There are two basic problems: first, the natural background level of variation of the climate on longer timescales (decades and centuries) is not precisely known, since we don't have accurate global measurements for very long, so it is very hard to tell whether any given observed change in the weather is natural or artificial. There is geological evidence of large and sudden changes of climate in the past, long before humans industrialised, and we don't know how they all work or how big they can get.&lt;/p&gt;&#xA;&lt;p&gt;The second problem is that while the opacity of CO2 to infrared has been known about for a long time, this is only part of the story. There are a large number of &lt;em&gt;feedback mechanisms&lt;/em&gt; that can magnify or reduce the effect of CO2, and these are often poorly understood. For example, warming due to CO2 is thought to cause more water vapour to evaporate, and water is also a powerful greenhouse gas - a positive feedback. But water vapour also reduces the lapse rate in the atmosphere (the rate at which temperature drops with height), which is a negative feedback. The biggest uncertainty is the effect on clouds. Current climate models have the effect of multiplying the effect of CO2 alone by about 3; around two thirds of the projected effect are thus due to other causes. But the error bars on that estimate are huge, and there is an ongoing scientific debate about whether the empirical measurements agree.&lt;/p&gt;&#xA;&lt;p&gt;From p688 of the linked report:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Both detection and attribution require knowledge of the&#xA;internal climate variability on the time scales considered,&#xA;usually decades or longer&lt;/strong&gt;. The residual variability that remains&#xA;in instrumental observations after the estimated effects of&#xA;external forcing have been removed is sometimes used to&#xA;estimate internal variability. However, &lt;strong&gt;these estimates are&#xA;uncertain&lt;/strong&gt; because the instrumental record is too short to give&#xA;a well-constrained estimate of internal variability, and because&#xA;of uncertainties in the forcings and the estimated responses.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;From p669:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The approaches used in detection and attribution research&#xA;described above &lt;strong&gt;cannot fully account for all uncertainties&lt;/strong&gt;,&#xA;and thus ultimately &lt;strong&gt;expert judgement is required&lt;/strong&gt; to give a&#xA;calibrated assessment of whether a specific cause is responsible&#xA;for a given climate change. The assessment approach used in&#xA;this chapter is to consider results from multiple studies using a&#xA;variety of observational data sets, models, forcings and analysis&#xA;techniques. The assessment based on these results typically&#xA;takes into account the &lt;strong&gt;number of studies, the extent to which&#xA;there is consensus among studies on the significance of detection&#xA;results, the extent to which there is consensus on the consistency&#xA;between the observed change and the change expected from&#xA;forcing, the degree of consistency with other types of evidence,&#xA;the extent to which known uncertainties are accounted for&#xA;in and between studies, and whether there might be other&#xA;physically plausible explanations for the given climate change&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;As an aside, while Fourier did publish some predictions on the effect of CO2 on temperature, the mechanism he described &lt;em&gt;does not apply in a convective atmosphere&lt;/em&gt;. The correct mechanism was actually identified during the study of the atmosphere of stars in the 1940s, and was applied to planetary atmospheres by &lt;a href=&quot;https://climate-dynamics.org/wp-content/uploads/2016/06/manabe64a.pdf&quot; rel=&quot;noreferrer&quot;&gt;Manabe and Strickler&lt;/a&gt; in the early 1960s.&lt;/p&gt;&#xA;&lt;p&gt;When gases are compressed, they warm up, and when gases are allowed to expand, they cool. So as the atmosphere circulates convectively, rising air cools and descending air warms. This sets a particular temperature gradient in the atmosphere, called the &lt;em&gt;adiabatic lapse rate&lt;/em&gt;. Temperature gradients much larger than this cannot normally be maintained, as convection starts up and transports heat vertically to cancel out the excess. Moist air has a lower adiabatic lapse rate than dry air, about 6.5 C/km on average.&lt;/p&gt;&#xA;&lt;p&gt;To a very close approximation, all the energy from the sun that arrives on Earth is subsequently radiated as infrared to outer space - the black body temperature needed to radiate this much energy is about -20 C. However, when the atmosphere is opaque to infrared, it radiates not from the ground, but from the first 10 km of the atmosphere. The average altitude of emission to space is about 5 km. So it is the air at this altitude settles at -20 C. And because of the adiabatic lapse rate, the surface is roughly 6.5*5 = 32.5 C warmer (i.e. about +13 C.) This is the greenhouse effect in a convective atmosphere. (In an atmosphere without convection, using Fourier's mechanism, the surface temperture would be about 60 C.) More CO2 and water vapour raises the average altitude of infrared emission to space, thus raising the surface temperature. But more water vapour reduces the vertical temperature gradient, &lt;em&gt;reducing&lt;/em&gt; the surface temperature rise and at the same time &lt;em&gt;increasing&lt;/em&gt; the temperature of the upper troposphere 10 km up. If you look at figure 9.1 panels (c) and (f) on p675 of the IPCC Report linked, which show where the models say the warming will be seen, you will see this as a big red blob in the middle of the picture. This is the 'fingerprint' of water vapour feedback.&lt;/p&gt;&#xA;&lt;p&gt;Please note - everything I say here comes from the AR4 IPCC Report or the mainstream climate literature.&lt;/p&gt;&#xA;" OwnerUserId="27237" LastEditorUserId="27237" LastEditDate="2022-07-20T23:27:56.520" LastActivityDate="2022-07-20T23:27:56.520" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24064" PostTypeId="1" CreationDate="2022-07-21T00:14:02.313" Score="2" ViewCount="55" Body="&lt;p&gt;Long ago, Chris Wayans, a worldbuilder, created a thought experiment switching Earth's depth with height, and vice versa.  The result:  Abyssia.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oDb2Y.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oDb2Y.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;He even went as far as listing the following geographical proportions by the numbers:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Land=12% of the planet's surface&lt;/li&gt;&#xA;&lt;li&gt;Shallow seas=13% of the planet's surface&lt;/li&gt;&#xA;&lt;li&gt;Deep seas (1-4 kilometers deep)=40% of the planet's surface&lt;/li&gt;&#xA;&lt;li&gt;Abyssal plains (5-6 kilometers deep)=32% of the planet's surface&lt;/li&gt;&#xA;&lt;li&gt;Trenches and deeps (Over 6 kilometers deep)=3% of the planet's surface&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;How does this compare to Earth's oceans in real life?  For this question, we'll have to disregard all land, which we pretty much know makes up 29% of the planet's surface.  All I know is that the shallows make up eight percent of the Earth's oceans, but what about the deep seas, the abyssal plains and the trenches and deeps?  How much of Earth's oceans do they make up?&lt;/p&gt;&#xA;" OwnerUserId="4985" LastActivityDate="2022-08-06T00:53:26.473" Title="How much of Earth's oceans has each of the listed features?" Tags="|oceanography|geography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24065" PostTypeId="2" ParentId="15823" CreationDate="2022-07-21T02:51:43.943" Score="2" Body="&lt;p&gt;Those models seem fairly simple. The keyword there is the word &amp;quot;boil&amp;quot;, I think. Consider the analogy with boiling water in a kettle. The water acts as a thermostat (of sorts) preventing the temperature from rising too much and ruining/burning the kettle. But once the water &amp;quot;runs out&amp;quot;, i.e. it has all evaporated...&lt;/p&gt;&#xA;&lt;p&gt;And when it comes to the Earth (or any planet), the extra vapor also acts a greenhouse gas, effectively turning up the heat. That much is made clear in the intro to the 2013 paper, which refers to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Runaway_greenhouse_effect#The_moist_greenhouse_limit&quot; rel=&quot;nofollow noreferrer&quot;&gt;Simpson-Nakajima limit&lt;/a&gt; in that regard. Numerically estimating this limit is actually not that simple though.&lt;/p&gt;&#xA;" OwnerUserId="11964" LastEditorUserId="11964" LastEditDate="2022-07-21T05:48:02.267" LastActivityDate="2022-07-21T05:48:02.267" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24068" PostTypeId="1" CreationDate="2022-07-21T14:10:16.813" Score="2" ViewCount="83" Body="&lt;p&gt;I was just wondering how much the vapour pressure has changed due to climate change. Because with changing temperatures, the vapour pressure also changes; this is described by the Clausius-Clapeyron equation. Does anyone have a suitable paper on how this has changed in the Northern hemisphere?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-08-11T17:26:48.020" LastActivityDate="2022-08-11T17:26:48.020" Title="Change in vapour pressure due to climate change" Tags="|climate-change|climate|water|water-vapour|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24069" PostTypeId="1" CreationDate="2022-07-21T16:59:34.393" Score="1" ViewCount="48" Body="&lt;p&gt;Based on the &lt;code&gt;maximum air temperature Time series plot&lt;/code&gt; plot below. What could be a possible reason(s) for &lt;code&gt;Maximum Temperature&lt;/code&gt; to decrease over time, even though &lt;code&gt;minimum and mean&lt;/code&gt; temperatures are increasing? And actually, I only this behavior in the some months not all of them which is also interesting.&lt;/p&gt;&#xA;&lt;p&gt;Someone did tell me that &lt;code&gt;Maximum temperature&lt;/code&gt; tends to show this behavior in a timeseries, but didn't tell me why.&lt;/p&gt;&#xA;&lt;p&gt;The area is a coastal region in North America and the data was collected from the PRISM model.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ASFCF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ASFCF.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27254" LastEditorUserId="27254" LastEditDate="2022-07-21T17:32:30.673" LastActivityDate="2022-07-21T17:32:30.673" Title="Maximum Air Temperature Decrease Over Time" Tags="|climate-change|temperature|climatology|air|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="24072" PostTypeId="1" CreationDate="2022-07-22T19:27:26.780" Score="4" ViewCount="66" Body="&lt;p&gt;When sources describe global warming potential of different gasses, such as in &lt;a href=&quot;https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter08_FINAL.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper on radiative forcing&lt;/a&gt;, methane and tropospheric ozone respectively are given GWP values of around 29 and 65. However, when I look at spectra for the three gasses or &lt;a href=&quot;https://www.giss.nasa.gov/research/briefs/2010_schmidt_05/&quot; rel=&quot;nofollow noreferrer&quot;&gt;diagrams showing outgoing blackbody radiation from the earth&lt;/a&gt;, it doesn't look like the radiative forcing effect for methane and tropospheric ozone should be that much higher than CO2. I've hunted around a bit, and have seen the same values for GWP of methane and ozone in many sources, but haven't been able to figure out why those gasses are so much more potent than CO2.&lt;/p&gt;&#xA;&lt;p&gt;Why is the global warming potential of tropospheric ozone and methane so high?&lt;/p&gt;&#xA;" OwnerUserId="27267" LastActivityDate="2022-07-22T19:27:26.780" Title="Why is the global warming potential of methane and ozone so much higher than CO2?" Tags="|climate-change|greenhouse-gases|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24076" PostTypeId="2" ParentId="24055" CreationDate="2022-07-23T13:05:34.267" Score="3" Body="&lt;p&gt;It is a chemical concretion. the shape and structure are a common form of concretion. there may be a tiny flake of fossil that acted as a seed for chemical deposition but this could be microscopic or long dissolved. the fibers are likely bacterial.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zyyuc.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zyyuc.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CaC9G.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CaC9G.jpg&quot; alt=&quot;https://64.media.tumblr.com/5a72154ffff42462f7164519b3e63d20/tumblr_p0oghyxcGo1sq04bjo1_250.jpg&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://onlinelibrary.wiley.com/doi/full/10.1002/dep2.139&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://onlinelibrary.wiley.com/doi/full/10.1002/dep2.139&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2022-07-23T13:05:34.267" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24077" PostTypeId="1" AcceptedAnswerId="24078" CreationDate="2022-07-24T08:37:49.643" Score="7" ViewCount="1138" Body="&lt;p&gt;Max/min Thermometer readings from a weather station with Stevenson screen are subject to noise from many sources and represent the max/ min at that one point in space.&lt;/p&gt;&#xA;&lt;p&gt;It's well known that underground temperatures are stable at, I believe, the average year-round temperature. They would then make a much better way of measuring average temperature over years.&lt;/p&gt;&#xA;&lt;p&gt;Do any underground instrumental temperature records exist?&lt;/p&gt;&#xA;" OwnerUserId="27110" LastActivityDate="2022-07-24T18:23:54.150" Title="Underground temperature record" Tags="|meteorology|paleoclimatology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24078" PostTypeId="2" ParentId="24077" CreationDate="2022-07-24T16:01:43.997" Score="8" Body="&lt;p&gt;There are many underground temperature measurements. Monitoring of permafrost is one instance where underground temperature has been monitored for many years. In Europe there are many boreholes reaching about 100 m under ground that measure temperature. A project called Permafrost and Climate in Europe (PACE) established a network of bore holes that monitor ground temperatures from Svalbard to Spain (Harris et al. 2009). Results from one of these boreholes in Tarfala, Sweden, (67.9098° N, 18.6101° E) has shown warming trends in the upper parts of the bore hole since establishment in the year 2000 (Bolin Centre, no year).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EgE2k.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EgE2k.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The upper pane in the figure shows the air temperature (in degrees Celsius) at the PACE bore hole at 1650 m a.s.l. (red) as well as the monthly average temperature at the Tarfala Research Station (1130 m a.s.l.; blue) in the northern Swedish mountains. The lower three graphs show the temperature (again in degrees Celsius) at the depths of 25, 30 and 40 m below the ground surface. As can be seen warming occurs at depth. In this particular bore hole the seasonal effects of summer and winter reaches about 20 m below ground level so the presented curves shows the longer term trends in ground temperature. There are some spurious deviations likely caused by water leaking into the bore hole and refreezing causing momentary increases in temperature due to the release of heat as the phase change from liquid to solid occurs.&lt;/p&gt;&#xA;&lt;p&gt;The extrapolated depth of the transition from negative (permafrost) to positive temperature is about 300 m below the ground at this site.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Bolin Centre for Climate Research: Tarfala Data, Permafrost. (Data base)&#xA;&lt;a href=&quot;https://bolin.su.se/data/tarfala/permafrost.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://bolin.su.se/data/tarfala/permafrost.php&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Harris et al 2009. Permafrost and climate in Europe: Monitoring and modelling thermal, geomorphological and geotechnical responses. Earth-Science Reviews.&#xA;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0012825208001311&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/S0012825208001311&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="81" LastEditDate="2022-07-24T18:23:54.150" LastActivityDate="2022-07-24T18:23:54.150" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24079" PostTypeId="2" ParentId="17990" CreationDate="2022-07-25T07:49:15.513" Score="0" Body="&lt;p&gt;There have been &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_offset&quot; rel=&quot;nofollow noreferrer&quot;&gt;Carbon Offset schemes&lt;/a&gt; by some nations, that pay for tree planting (or in some cases pay for not cutting down trees) in place of actual emissions reductions.&lt;/p&gt;&#xA;&lt;p&gt;The politics around these can get murky with respect to motivations (&amp;quot;why&amp;quot;) but include both sincere efforts to make these work as one element of an emissions reduction policy - usually as a kind of stopgap action to give time for new investments in low emissions energy to flow through - as well as insincere efforts, to appear pro-active whilst not requiring substantive change to emitting industries. Or even to cash in on emissions reduction funding and/or funnel it inappropriately as political favors.&lt;/p&gt;&#xA;&lt;p&gt;Because the climate issue had initially been widely framed as environmental and fringe rather than economic and mainstream it had been seen widely as driven by environmentalists who have long opposed land clearing and promoted re-forestation. Some of these schemes appear to have been developed by environmentalists and some to appease Environmentalists (and an increasing concerned public) who promote tree planting as a simple and environmentally beneficial act irrespective of climate change.&lt;/p&gt;&#xA;&lt;p&gt;The climate problem has increasingly become seen as economic and mainstream over time and the effectiveness of reforestation as Carbon Offsets faces ongoing scrutiny, including by &amp;quot;green&amp;quot; political parties and others concerned with &amp;quot;greenwashing&amp;quot; (the contrived appearance of supporting emissions reductions goals whilst avoiding emissions reductions.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="18145" LastEditDate="2022-07-25T07:56:45.007" LastActivityDate="2022-07-25T07:56:45.007" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24081" PostTypeId="1" CreationDate="2022-07-25T12:53:32.820" Score="1" ViewCount="251" Body="&lt;p&gt;I get the following error messages when running the hydrological model MIKE-SHE:&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Cannot initialize MIKE-1D - Failed when solving for a steady state solution; water level being exceeded; Warning: Hyperthreading&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;I managed to get all my grid sizes to match the domain and finally got rid of the abnormal termination because of grid issues. In the pre-processing, it seems that all my other files were also fine i.e. see below from SimSpec and storing to Overland Data. However, when it gets to River Data I get an error in loading MIKE 1D d11… see below. I redid my MikeHydro with the same DEM as now in my MikeShe and I still get the same errors.&lt;/p&gt;&#xA;&lt;p&gt;I would be extremely grateful for any assistance on this issues of initialising Mike 1D&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7QSSn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7QSSn.png&quot; alt=&quot;Screen grab of error&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27288" LastActivityDate="2022-07-25T13:09:01.857" Title="Cannot initialize MIKE-1D - Failed when solving for a steady state solution; water level being exceeded; Warning: Hyperthreading" Tags="|hydrology|models|" AnswerCount="1" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="24084" PostTypeId="2" ParentId="24081" CreationDate="2022-07-25T13:09:01.857" Score="1" Body="&lt;p&gt;Looking at your cross-section file, there are some that need to be corrected. Have a look at the screenshot below. All your branches contain at least one cross-section that has its lowest elevation point at 0m. this needs to be corrected to be consistent with your other cross-sections.&lt;/p&gt;&#xA;&lt;p&gt;As a result of the bottom cross-section being 0m, you’ll need to redo the Q/h relationship for the outflow cross-section. Looking at the ones above, this should be between 450 – 500 m (meters above sea level). Once you’ve corrected these, hopefully the model will run. &lt;a href=&quot;https://i.stack.imgur.com/OPqkw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OPqkw.png&quot; alt=&quot;cross section errors&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27288" LastActivityDate="2022-07-25T13:09:01.857" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24085" PostTypeId="2" ParentId="17990" CreationDate="2022-07-25T14:29:15.667" Score="0" Body="&lt;p&gt;Trees do not trap only CO2, they trap water and water vapour is a major contributor to climate change. In any case the research you cited is purely theoretical because the current growth of existing and newly planted trees is not enough to offset the quantity of trees that we are cutting down.&lt;/p&gt;&#xA;&lt;p&gt;Other points:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the research you cited does not take into account the impact that forested areas have on rain cycles.&lt;/li&gt;&#xA;&lt;li&gt;the research you cited  assumes that all desert areas are covered by highly reflective quartz sand. But even in the Sahara you can find &lt;a href=&quot;https://en.wikipedia.org/wiki/Hbyamada&quot; rel=&quot;nofollow noreferrer&quot;&gt;dark rocky&lt;/a&gt; landscapes that trap a lot of heat.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="18774" LastEditorUserId="18774" LastEditDate="2022-07-25T15:34:59.377" LastActivityDate="2022-07-25T15:34:59.377" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24087" PostTypeId="2" ParentId="24051" CreationDate="2022-07-26T14:06:14.443" Score="3" Body="&lt;p&gt;On the temperature calculation using the &lt;sup&gt;18&lt;/sup&gt;O isotopes:&#xA;Calibration: The samples are always plotted against the VSMOW (Vienna Standard Mean Ocean Water) which is always 0 permil.&lt;/p&gt;&#xA;&lt;p&gt;Info:&#xA;We calibrate every Sample against recent ocean water Oxygen-18. 18O concentrations in the sample similar to the ocean water have a 18O signature about 0 permil&lt;/p&gt;&#xA;&lt;p&gt;The temperatures can be calculated according to the equations (in high latitudes):&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\delta^{18}\textrm{O} = (0.521 \pm 0.014)t_a - (14.96 \pm 0.21)^0\!\!/\!_{00}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;For further information: &lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/isotopic-fractionation&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/isotopic-fractionation&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It is a lovely introduction to this highly interesting topic! Keep interested in this topic!&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-07-27T07:39:59.303" LastActivityDate="2022-07-27T07:39:59.303" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24088" PostTypeId="1" AcceptedAnswerId="24089" CreationDate="2022-07-26T15:36:48.847" Score="4" ViewCount="1193" Body="&lt;p&gt;In a paper about the interior of the Moon, it references depleted mantle sources and enriched mantle sources. Sometimes the latter is referred to as 'fertile'. What is difference between the first two?&lt;/p&gt;&#xA;" OwnerUserId="27304" LastActivityDate="2022-07-26T19:24:45.127" Title="What is the difference between a depleted mantle, and a fertile or enriched mantle?" Tags="|volcanology|planetary-science|mantle|moon|magmatism|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24089" PostTypeId="2" ParentId="24088" CreationDate="2022-07-26T19:19:37.383" Score="4" Body="&lt;p&gt;Basically, a fertile mantle is a portion of mantle that has not experienced any melting. On the other hand, a depleted mantle has experienced partial melting, and subsequent extraction of this melt. During partial melting, some elements will preferably go in the melt while others will preferably stay in the mantle. This leaves the residual mantle with a different chemical/mineral composition, which is more refractory, i.e., less likely to melt.&lt;/p&gt;&#xA;&lt;p&gt;So &amp;quot;fertile&amp;quot; here means &amp;quot;can (partially) melt&amp;quot;, while &amp;quot;depleted&amp;quot; means &amp;quot;cannot melt (because already did)&amp;quot;. Corresponding mantle rocks are usually lherzolite and harzburgite, respectively. See for instance the &lt;a href=&quot;https://en.wikipedia.org/wiki/Peridotite#Classification&quot; rel=&quot;nofollow noreferrer&quot;&gt;peridotite classification&lt;/a&gt; article on Wikipedia:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Harzburgite [...] is interpreted as depleted mantle rock, from which basaltic magma has been extracted.&lt;/li&gt;&#xA;&lt;li&gt;Lherzolite is thought to make up much of the upper mantle [...] and is the likely source rock for basaltic magma.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2022-07-26T19:24:45.127" LastActivityDate="2022-07-26T19:24:45.127" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24090" PostTypeId="1" CreationDate="2022-07-27T10:36:25.593" Score="2" ViewCount="45" Body="&lt;p&gt;Recently, crop monitoring through satellite or other remote sensing devices has become a hot topic. However, I was wondering if, say, satellite data combined with ML software mapping out crops being grown in different parts of the map of the region would really be of use to a farmer since it seems that the farmer would obviously already know these things beforehand. What exactly is the information gained by the farmer, especially if the farmer is engaging in intensive farming, from crop monitoring through remote sensing and AI combination that the farmer already didn't know?&lt;/p&gt;&#xA;" OwnerUserId="27307" LastActivityDate="2022-07-27T10:36:25.593" Title="Do farmers gain any particular benefits from crop monitoring?" Tags="|remote-sensing|agriculture|machine-learning|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24091" PostTypeId="1" AcceptedAnswerId="24093" CreationDate="2022-07-27T10:59:21.453" Score="5" ViewCount="222" Body="&lt;p&gt;Found this on open heath land close to RAF Honington, Suffolk, UK. Its about the size/shape of a cherry tomatoe cut in half.&lt;/p&gt;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7WPjt.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7WPjt.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/unp51.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/unp51.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27308" LastEditorUserId="26841" LastEditDate="2022-07-27T15:02:50.483" LastActivityDate="2022-07-27T15:02:50.483" Title="Is this a fossil?" Tags="|geology|paleontology|fossils|" AnswerCount="1" CommentCount="0" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24092" PostTypeId="1" CreationDate="2022-07-27T12:18:49.630" Score="6" ViewCount="417" Body="&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Falkland_Islands&quot; rel=&quot;nofollow noreferrer&quot;&gt;Falkland Islands&lt;/a&gt; have an extensive territory, they are sparsely populated and they are on the path of the southern winds, which blow almost constantly.The wind power potential should be enormous.&lt;/p&gt;&#xA;&lt;p&gt;Such potential has never been exploited because they are too isolated, but I was wondering if the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydrogen_economy&quot; rel=&quot;nofollow noreferrer&quot;&gt;hydrogen economy&lt;/a&gt; could change that.  Transporting hydrogen over a long distance would be dangerous, but the electricity produced on the islands could be used to produce &lt;a href=&quot;https://en.wikipedia.org/wiki/Calcium_hydride&quot; rel=&quot;nofollow noreferrer&quot;&gt;calcium hydride&lt;/a&gt;, or pure magnesium or any other element or compound that reacts with water producing hydrogen. That could be a safe way to transport hydrogen. The economic returns could be good because also the byproducts will be useful, burning hydrogen you get fresh water and calcium hydride would be turned into caustic lime.&lt;/p&gt;&#xA;&lt;p&gt;What could be the actual potential of such project? Just looking at the map it appears that the islands could produce several gigawatts of electricity simply using inshore turbines. One caveat is that I don't know if the islands have the enough manpower for such project.&lt;/p&gt;&#xA;" OwnerUserId="18774" LastEditorUserId="2470" LastEditDate="2022-07-28T17:22:10.990" LastActivityDate="2023-10-18T08:34:24.570" Title="What is the wind power potential of the Falkland islands?" Tags="|wind|energy|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24093" PostTypeId="2" ParentId="24091" CreationDate="2022-07-27T12:22:58.120" Score="4" Body="&lt;p&gt;Yes it could be a fossil. Btw. it is called a sand dollar.&#xA;The term sand dollar refers to several species of flattened burrowing sea urchins that belong to the order Clypeasteroidea. Sand dollars, sometimes called sea biscuits or sea cucumbers, are closely related to sea urchins, sea cucumbers and starfish.&lt;/p&gt;&#xA;&lt;p&gt;They are found under the mud and sand in waters virtually everywhere in the world in temperate zones. Sand dollars first appeared about 60 million years ago, at the beginning of the Paleocene era.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/McOky.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/McOky.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.gomeravive.com/de/wissen/meer-wissen/die-schoenen-und-die-biester/stachelhaeuter/&quot; rel=&quot;noreferrer&quot;&gt;https://www.gomeravive.com/de/wissen/meer-wissen/die-schoenen-und-die-biester/stachelhaeuter/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-07-27T13:13:26.820" LastActivityDate="2022-07-27T13:13:26.820" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24095" PostTypeId="1" CreationDate="2022-07-27T15:36:16.127" Score="3" ViewCount="69" Body="&lt;p&gt;The stratopause is separating the stratosphere from the mesosphere around 47-53 km (29-33 mi) altitude. Standard atmosphere models give its temperature as minus 2.5°C, but how strong are its variations as per latitude and season? What's the lowest and what's the highest stratopause temperature ever recorded by radiosonde or sounding rocket data, and at what time and above what latitude?&lt;/p&gt;&#xA;" OwnerUserId="27157" LastEditorUserId="27157" LastEditDate="2022-07-28T10:07:27.867" LastActivityDate="2022-07-28T10:07:27.867" Title="What are the coldest and hottest ever recorded temperatures at the stratopause?" Tags="|temperature|stratosphere|radiosounding|" AnswerCount="0" CommentCount="12" FavoriteCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24096" PostTypeId="1" CreationDate="2022-07-27T15:39:40.533" Score="2" ViewCount="28" Body="&lt;p&gt;Currently, I am setting up a hydrodynamic model for a coastal zone. For this purpose I need to impose the velocity and water level at the open boundary.&lt;/p&gt;&#xA;&lt;p&gt;Tidal models (e.g. TPXO) can give both velocity (U, V) and water depth. But, if the water depth time series is measured over time, how can we derive the velocity (U, V) from it?&lt;/p&gt;&#xA;" OwnerUserId="12479" LastActivityDate="2022-07-27T15:39:40.533" Title="Velocity boundary conditions from water depth time series" Tags="|oceanography|models|ocean-currents|tides|ocean-models|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24097" PostTypeId="1" AcceptedAnswerId="24099" CreationDate="2022-07-27T17:43:06.733" Score="3" ViewCount="83" Body="&lt;p&gt;There are certainly oilfields under the sea floor off the coast of Sakhalin, that are being actively exploited. This map shows their locations: &lt;a href=&quot;https://www.researchgate.net/figure/Map-of-Sakhalin-Island-showing-offshore-oil-and-gas-blocks-and-study-locations-Okha_fig1_248393621&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/figure/Map-of-Sakhalin-Island-showing-offshore-oil-and-gas-blocks-and-study-locations-Okha_fig1_248393621&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But one thing that jumps out at me about that map is that it seems to also be showing some oilfields on the island itself.&lt;/p&gt;&#xA;&lt;p&gt;If that is the case, would those not be easier to reach than the offshore ones, therefore exploited first? Yet I cannot find any mention of that in e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Sakhalin-I&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Sakhalin-I&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Am I misreading the map, is there some other difficulty, or have onshore oil fields indeed been exploited?&lt;/p&gt;&#xA;" OwnerUserId="7911" LastEditorUserId="6129" LastEditDate="2022-07-29T17:47:38.493" LastActivityDate="2022-07-29T17:47:38.493" Title="Is or was there oil on Sakhalin?" Tags="|geology|economic-geology|petroleum|arctic|oil-reserves|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24098" PostTypeId="1" CreationDate="2022-07-27T18:08:07.960" Score="2" ViewCount="73" Body="&lt;p&gt;My goal is to build an algorithm whose fundamental goal at the most basic level is, given the current tree configuration of a particular region, to output the best coordinates to plant the next tree. &lt;em&gt;Tree configuration&lt;/em&gt; refers to the coordinates of all the trees in a particular region.&lt;/p&gt;&#xA;&lt;p&gt;Let me begin by defining the term &lt;em&gt;tree utility&lt;/em&gt;, which includes the overall qualitative measure of properties such as the integrity of the forest, thriving capability of the local ecosystem, reduced competition of resources (for the trees), and so on.&lt;/p&gt;&#xA;&lt;p&gt;From &lt;a href=&quot;https://www.mdpi.com/1999-4907/12/8/981&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; paper by Xu et al. (2021), I get the notion that naturally formed forests tend towards a uniform spatial distribution. But I'm not confident regarding my inference, being entirely untrained in this field. I am aware that the paper was based on the forest patterns of a particular species of plants. But the quoted text below from the mentioned paper pursued me to believe that at least my inference - a uniform spatial structure maximizes &lt;em&gt;tree utility&lt;/em&gt; - can be generalized to most, if not all species&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The study on the structure of natural forests based on uniform angle index distribution shows that the number of trees in a random distribution microenvironment in natural forests is more than 50% and can usually be divided into two types, R1 (dumbbell-shaped random unit) and R2 (torch-shaped random unit) (Figure 1), with a similar proportion (R1:R2 = 1:2), and it has nothing to do with forest distribution zone, tree species, or forest type&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Assuming my inference isn't wrong, I devised the following basic framework for the mathematical model I'll use to build my algorithm.&lt;/p&gt;&#xA;&lt;p&gt;Consider a 4x4 grid and suppose a tree exists at position (1,1), the top left corner. Where should I plant the next tree to maximize the &lt;em&gt;tree utility&lt;/em&gt; of the area?&lt;/p&gt;&#xA;&lt;p&gt;I hypothesize that the more adjacent trees there are to a unit square in the grid, the better it is. Which makes (2,2) the answer to the question I asked above. The mathematical model I will build based on this hypothesis will generalize this process to an arbitrary MxN grid.&lt;/p&gt;&#xA;&lt;p&gt;The ultimate implication of this hypothesis is that the closer the tree distribution in a given region is to a uniform distribution, the more the &lt;em&gt;tree utility&lt;/em&gt; is maximized. I try to illustrate my point a little better through the images below.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/i0tBs.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/i0tBs.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/rAV7t.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rAV7t.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/4n2k9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4n2k9.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Put short,&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Is my inference from the mentioned paper by Xu et al. correct?&lt;/li&gt;&#xA;&lt;li&gt;Is my hypothesis - the closer a forest's spatial distribution is to uniformity, the higher the &lt;em&gt;tree utility&lt;/em&gt; - sound? If yes, I'd appreciate references to related literature. If not, please elaborate on the reasons for it to be fallacious.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="27311" LastEditorUserId="27311" LastEditDate="2022-07-29T01:49:43.600" LastActivityDate="2022-07-29T01:49:43.600" Title="Maximizing Tree Utility in a given Region" Tags="|forest|reference-request|grid-spacing|" AnswerCount="0" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="24099" PostTypeId="2" ParentId="24097" CreationDate="2022-07-28T03:15:52.907" Score="4" Body="&lt;p&gt;Onshore oil deposits, &lt;strong&gt;on&lt;/strong&gt; the island of &lt;a href=&quot;https://link.springer.com/referenceworkentry/10.1007/978-3-642-40871-7_117-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sakhalin&lt;/a&gt; have existed. The were discovered in 1928 by a Russian-Japanese venture. Oil production from onshore deposits began in 1930.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;There has been oil production on the island of Sakhalin in Russia’s Far East, since 1928, when a joint Russian–Japanese venture discovered oil onshore, and the local oil company Sakhalinmorneftegaz (SMNG) has been producing onshore since the 1930s.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-07-28T03:15:52.907" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24100" PostTypeId="2" ParentId="23489" CreationDate="2022-07-28T09:22:40.697" Score="4" Body="&lt;p&gt;Volcano Café just published a series of articles about Nyiragongo, with &lt;a href=&quot;https://www.volcanocafe.org/nyiragongo-and-its-ultra-alkaline-magma-part-ii/&quot; rel=&quot;nofollow noreferrer&quot;&gt;one part&lt;/a&gt; answering this very question: &amp;quot;Steep slopes despite very fluid lavas. How Nyiragongo got it shape&amp;quot;. (It is not a peer-reviewed article, but the site usually publish scientifically accurate, well-sourced articles.)&lt;/p&gt;&#xA;&lt;p&gt;In summary, despite being ultrabasic, Nyiragongo is not a classic shield volcano made of a succession of lava flows building a cone with gentle slopes. If you look at the caldera walls, you can see that most of the volcano is actually made of tephra, not lava. This is interpreted as phases of lava fountaining, consistent with the high gas content of Nyiragongo magma. Such activity usually build cones with steep slopes, corresponding to the angle of repose of loose pyroclasts. Occasional lava flows and/or overflows from a lava lake could have helped maintain this shape by protecting the tephra layers from erosion. As the article points out, Nyiragongo is not the only basaltic volcano with steep slopes: volcanoes such as Shishaldin and Villaricca are also good examples of steep tephra cones built by basaltic lava fountaining.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2022-07-28T09:22:40.697" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24101" PostTypeId="1" AcceptedAnswerId="24102" CreationDate="2022-07-28T09:23:36.253" Score="0" ViewCount="107" Body="&lt;p&gt;I was just wondering whether it wouldn't make more sense to describe climate change as global change. After all, it is not only the air temperature that has been changing in recent years, but also ice caps that are melting and storms that are increasing, etc. So although this change is all dependent on the climate, it is much more complex. Or is science already naming this global change?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2022-07-28T12:15:57.527" Title="Global change or climate change" Tags="|climate-change|" AnswerCount="1" CommentCount="1" ClosedDate="2022-07-31T13:35:40.830" ContentLicense="CC BY-SA 4.0" />
  <row Id="24102" PostTypeId="2" ParentId="24101" CreationDate="2022-07-28T12:15:57.527" Score="2" Body="&lt;p&gt;&amp;quot;What's in a name &lt;sup&gt;1&lt;/sup&gt;?&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;My initial &amp;quot;remembrance&amp;quot;, thanks to the mass media, was that the term global warming was first introduced in the early 1970s and that it was a controversial term amongst conservatives because the implications were industry and science were responsible for &amp;quot;something bad&amp;quot;, which ultimately could affect their investments and incomes. So as to make the affects on the world seems less contentious they introduced the term climate change.&lt;/p&gt;&#xA;&lt;p&gt;It appears &lt;a href=&quot;https://www.nasa.gov/topics/earth/features/climate_by_any_other_name.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;the situation&lt;/a&gt; was a little different.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.energyandcapital.com/articles/the-name-game-from-global-warming-to-climate-change-/97908&quot; rel=&quot;nofollow noreferrer&quot;&gt;In the 1960s&lt;/a&gt;, &amp;quot;concerns over CO&lt;sub&gt;2&lt;/sub&gt;-induced climate change begin to mount in the United States and the Soviet Union&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;The term “inadvertent climate modification” started being used in the late 1960s and early 1970s. One example being the title of a Swedish study titled &lt;em&gt;Inadvertent Climate Modification: Report of the Study of Man's Impact on Climate (SMIC)&amp;quot; is one example of the terms use&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The term “inadvertent climate modification” was being used by scientists&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;because while many scientists accepted that human activities could cause climate change, they did not know what the direction of change might be. Industrial emissions of tiny airborne particles called aerosols might cause cooling, while greenhouse gas emissions would cause warming. Which effect would dominate?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The term &amp;quot;global warming&amp;quot; was first used in 1975 by Wallace Broecker in a article titled, &lt;em&gt;Climatic Change: Are We on the Brink of a Pronounced Global Warming?&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;A 1979 study by the National Academy of Science, called the Charney Report, stated,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;if carbon dioxide continues to increase, [we find] no reason to doubt that climate changes will result and no reason to believe that these changes will be negligible.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;When referring to surface temperature change, Charney used &amp;quot;global warming.&amp;quot; When discussing the many other changes that would be induced by increasing carbon dioxide, Charney used &amp;quot;climate change.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;These terms are still used in scientific journals.&lt;/p&gt;&#xA;&lt;p&gt;In the late 1980s, the term &amp;quot;global change&amp;quot; was introduced.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This term encompassed many other kinds of change in addition to climate change.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;sup&gt;1&lt;/sup&gt;? &lt;a href=&quot;https://nosweatshakespeare.com/quotes/soliloquies/whats-in-a-name/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Thanks to Shakespeare&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-07-28T12:15:57.527" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24103" PostTypeId="5" CreationDate="2022-07-28T14:50:14.147" Score="0" Body="" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2022-07-28T14:50:14.147" LastActivityDate="2022-07-28T14:50:14.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24104" PostTypeId="4" CreationDate="2022-07-28T14:50:14.147" Score="0" Body="A volcanic eruption happens when magma reaches the surface, either effusively (as lava) or explosively (as tephra)." OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2022-07-28T14:50:14.147" LastActivityDate="2022-07-28T14:50:14.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24105" PostTypeId="2" ParentId="24092" CreationDate="2022-07-28T17:19:05.863" Score="4" Body="&lt;p&gt;The wind power potential in the Falkland Islands is very good.&lt;/p&gt;&#xA;&lt;p&gt;In 2016 the islands &lt;a href=&quot;https://www.worldometers.info/electricity/falkland-islands-malvinas-electricity/&quot; rel=&quot;noreferrer&quot;&gt;generated 19 GWh&lt;/a&gt; of electricity. Of this 53 percent was generated by fossil fuels and the remaining 47 percent was generated by wind turbines.&lt;/p&gt;&#xA;&lt;p&gt;As of &lt;a href=&quot;https://sd-windenergy.com/wind-turbine-news-events/falklands/&quot; rel=&quot;noreferrer&quot;&gt;December 2021&lt;/a&gt;, one energy company on the Falkland Islands had already installed in excess of 100 wind turbines. These turbines alone generate 12.5 GWh of electricity per annum. Wind speeds on the islands are 8.5 m/s during summer and 14 m/s during winter.&lt;/p&gt;&#xA;&lt;p&gt;As to the potential for using wind power to produce hydrogen, there are plans to do this in the &lt;a href=&quot;https://www.worldoil.com/news/2022/6/16/south-american-island-pitches-6-billion-wind-hydrogen-energy-plan/&quot; rel=&quot;noreferrer&quot;&gt;Tierra del Fuego province of Argentina&lt;/a&gt;. Something similar could be achieved on the Falkland Islands. If sheep farmers are hesitant to have wind turbines on their properties, off shore wind farms could be established.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-07-28T17:19:05.863" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24106" PostTypeId="1" CreationDate="2022-07-31T19:52:15.563" Score="3" ViewCount="44" Body="&lt;p&gt;I've been tracking the global jet streams for several years now. Over time, I've noticed that the Northern hemisphere jet streams appear much thinner, slower, and less well organized than their counterparts to the South, which appear much more robust and better organized. What's going on here, and does this imbalance have any significance/meaning with respect to climate change?&lt;/p&gt;&#xA;" OwnerUserId="27333" LastActivityDate="2022-07-31T19:52:15.563" Title="Imbalance between North and South hemisphere jet streams" Tags="|jet-stream|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24107" PostTypeId="2" ParentId="23935" CreationDate="2022-08-01T08:23:10.650" Score="2" Body="&lt;p&gt;This won't be a problem if you store it properly.&#xA;&lt;strong&gt;Make sure it's away from your children..&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;If it's exposed to the skin it can cause itching&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;If it's consumed it can cause diarrhea&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I suggest you to save it in a jar&lt;/p&gt;&#xA;" OwnerUserId="27336" LastActivityDate="2022-08-01T08:23:10.650" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24108" PostTypeId="1" CreationDate="2022-08-01T09:56:46.143" Score="3" ViewCount="32" Body="&lt;p&gt;I was just wondering if the precipitation in Europe has changed, for example, in its intensity or source? Has the source of the precipitation also changed? The water evaporates in the Atlantic. Is it possible that the polar amplification has caused it to evaporate further north?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2022-08-01T09:56:46.143" Title="How has precipitation changed in Europe?" Tags="|precipitation|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24109" PostTypeId="1" CreationDate="2022-08-01T10:32:00.740" Score="5" ViewCount="118" Body="&lt;p&gt;I was listening to a creepypasta story on YouTube about extremely deep places in the ocean deeper than the Marianas' Trench, and that makes me wonder.&lt;/p&gt;&#xA;&lt;p&gt;On Earth specifically, how deep could an ocean trench theoretically be? Would it be much deeper than Challenger Deep? I'm sure there is a limit to it, just as there's a limit to how tall a mountain can be, but I'm very curious to know what the limit may be.&lt;/p&gt;&#xA;" OwnerUserId="27339" LastEditorUserId="18081" LastEditDate="2022-08-01T12:53:02.890" LastActivityDate="2022-08-01T14:03:40.777" Title="How deep could an ocean trench be on Earth theoretically?" Tags="|geology|oceanography|geography|geodynamics|" AnswerCount="1" CommentCount="1" ClosedDate="2022-08-02T12:15:43.840" ContentLicense="CC BY-SA 4.0" />
  <row Id="24110" PostTypeId="2" ParentId="24109" CreationDate="2022-08-01T14:03:40.777" Score="0" Body="&lt;p&gt;Oceanic trenches are formed by the subduction of an oceanic plate underneath usually a continental plate. So the depth of how deep a trench can be depends on the thickness of the plate that is not being subducted. However, as mentioned in the link, the depth of the MAriannen Trench is also the theortic maximum depth:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/71/how-deep-could-the-surface-of-the-earths-crust-get&quot;&gt;How deep could the surface of the Earth&amp;#39;s crust get?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2022-08-01T14:03:40.777" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24111" PostTypeId="1" CreationDate="2022-08-01T21:01:46.147" Score="5" ViewCount="76" Body="&lt;p&gt;I just read that the Congo River is &lt;a href=&quot;https://www.livescience.com/congo-river.html#:%7E:text=In%20addition%2C%20the%20Congo%20River,%2C%20according%20to%20Phys.org.&quot; rel=&quot;nofollow noreferrer&quot;&gt;&amp;gt;200m (650 ft) deep&lt;/a&gt; - I had no idea that this is even remotely possible!&lt;/p&gt;&#xA;&lt;p&gt;Q1: What are the processes leading to a river being this deep?&lt;/p&gt;&#xA;&lt;p&gt;Q2: By which method is the depth of rivers in this range measured?&lt;/p&gt;&#xA;" OwnerUserId="27341" LastEditorUserId="18081" LastEditDate="2022-08-04T08:36:09.940" LastActivityDate="2022-08-04T08:36:09.940" Title="Surprisingly deep rivers" Tags="|hydrology|rivers|bathymetry|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24113" PostTypeId="1" CreationDate="2022-08-02T10:40:47.763" Score="3" ViewCount="1190" Body="&lt;p&gt;I'm looking for a wind chill formula that will work from -10 °C to +50 °C and uses wind speed in km/h so that I can use this formula to add this element to a weather station I am programming. I don't need it in code, just the normal math formula will work. I couldn't find this exact formula on google, and I am hoping someone here will know.&lt;/p&gt;&#xA;" OwnerUserId="27223" LastEditorUserId="2470" LastEditDate="2022-08-02T13:10:50.210" LastActivityDate="2022-08-02T13:10:50.210" Title="What is a wind chill formula that will work from -10 C to +50 C and uses wind speed in km/h?" Tags="|meteorology|temperature|weather-forecasting|wind|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24114" PostTypeId="2" ParentId="24113" CreationDate="2022-08-02T12:49:35.233" Score="9" Body="&lt;p&gt;Wind chill is only relevant for cold temperatures. During hot temperatures, the affect of wind is to increase the felt temperatures.&lt;/p&gt;&#xA;&lt;p&gt;What would be more appropriate would be &lt;a href=&quot;https://media.bom.gov.au/social/blog/1153/apparent-feels-like-temperature/&quot; rel=&quot;noreferrer&quot;&gt;apparent temperature&lt;/a&gt;, also known as the &amp;quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Wind_chill#Australian_apparent_temperature&quot; rel=&quot;noreferrer&quot;&gt;feels like&lt;/a&gt;&amp;quot; temperature. This calculated temperature considers the effect of the dry bulb temperature, humidity and wind speed.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$ {\displaystyle \mathrm {AT} =T_{\mathrm {a} }+0.33e-0.7v-4.00}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where:&lt;/p&gt;&#xA;&lt;p&gt;T&lt;sub&gt;a&lt;/sub&gt; = dry bulb temperature (°C)&lt;/p&gt;&#xA;&lt;p&gt;e = water vapour pressure (hPa)&lt;/p&gt;&#xA;&lt;p&gt;v = wind speed (m/s) at an elevation of 10 m&lt;/p&gt;&#xA;&lt;p&gt;The vapour pressure can be calculated from the temperature and relative humidity using the equation:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$e = \frac{R H}{100} ⋅ 6.105 ⋅ exp ( \frac{17.27 ⋅ T a}{ 237.7 + T a} ) $&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where:&lt;/p&gt;&#xA;&lt;p&gt;T&lt;sub&gt;a&lt;/sub&gt; = dry bulb temperature (°C)&lt;/p&gt;&#xA;&lt;p&gt;RH = Relative humidity (%)&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$exp$&lt;/span&gt; represents the exponential function&lt;/p&gt;&#xA;&lt;p&gt;The Australian formula includes the important factor of humidity and is somewhat more involved than the simpler North American model.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-08-02T12:49:35.233" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24115" PostTypeId="1" CreationDate="2022-08-02T16:51:58.277" Score="1" ViewCount="25" Body="&lt;p&gt;Can earthquake causing cracks in the ground impact opening of sealed drainage pits in the ground?&lt;/p&gt;&#xA;" OwnerUserId="21250" LastActivityDate="2022-08-02T16:51:58.277" Title="Earthquake impacting opening of sealed drainage pits" Tags="|earthquakes|impacts|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24116" PostTypeId="2" ParentId="834" CreationDate="2022-08-02T19:04:26.293" Score="1" Body="&lt;p&gt;I was wandering around some seabed topos yesterday and found a spire at the bottom of the trench that rises from 35,000ft to 8,700, making this discrete and very steep spire about 26,000 feet high. &lt;a href=&quot;https://i.stack.imgur.com/fG9z1.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fG9z1.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27348" LastActivityDate="2022-08-02T19:04:26.293" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24117" PostTypeId="1" CreationDate="2022-08-02T19:57:13.593" Score="1" ViewCount="65" Body="&lt;p&gt;I was sniffing around some Mariana topo maps yesterday and found a really discrete spire that seems to start at 35,000 ft and rise to 8,700, making it 26,000 ft tall. As per the attached pictures. Is this actually the case? Doesn’t even seem like a seamount, although I appreciate it might be. Sooooo steep! How is this not really widely talked about?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/03Eov.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/03Eov.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27348" LastEditorUserId="18088" LastEditDate="2022-08-03T11:03:00.610" LastActivityDate="2022-08-03T11:03:00.610" Title="Biggest discrete spire on earth?" Tags="|oceanography|topography|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24118" PostTypeId="2" ParentId="9673" CreationDate="2022-08-02T22:03:49.573" Score="1" Body="&lt;p&gt;It's a combination of two main things:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Flexible buildings have a longer fundamental period and therefore are more sensitive to long-period waves.&lt;/li&gt;&#xA;&lt;li&gt;Earthquakes generate waves with a range of frequencies (or periods, which is inverse of frequency). High-frequency (short-period) waves attenuate quickly (i.e., over short distances) but the long-period waves take more distance to attenuate (because they are longer). So, the long-period waves travel further.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Other site-specific factors like basin effects also amplify long period ground motions. Like @user2821 said in the comments, the most significant damage in the 1985 Mexico City earthquake occurred on soil column with an elongated fundamental period of about 2 seconds, so mid- to high-rise buildings on the lacustrine soils did not fare well.&lt;/p&gt;&#xA;" OwnerUserId="27352" LastActivityDate="2022-08-02T22:03:49.573" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24119" PostTypeId="2" ParentId="9746" CreationDate="2022-08-03T04:05:03.817" Score="6" Body="&lt;p&gt;The top two pictures are of &lt;a href=&quot;https://atoptics.co.uk/droplets/iridim6.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;iridescence&lt;/a&gt; in a &lt;a href=&quot;https://en.wikipedia.org/wiki/Pileus_(meteorology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;pileus&lt;/a&gt; (AKA &amp;quot;cap cloud&amp;quot;) above a growing thunderstorm. Pileus clouds form when a storm updraft pushes up through a layer of moist air, and lifts that layer uniformly, causing it to condense into a thin layer of cloud. Since all the cloud droplets are formed at about the same time as this moist layer is lifted, they all end up roughly the same size, which is perfect conditions for iridescence to form.&lt;/p&gt;&#xA;&lt;p&gt;The term &amp;quot;fire rainbow&amp;quot; doesn't have a consistent definition, because it is a term invented by a journalist for phenomena that was already known and named: specifically the &lt;a href=&quot;https://atoptics.co.uk/halo/cha2.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;circumhorizon arc&lt;/a&gt;. This journalist apparently didn't bother to consult scientists (or even amateur skywatchers) to find out if it already had a name, and so gave it this artistic name: I'm guessing the &amp;quot;fire&amp;quot; in fire rainbow is supposed to describe the &amp;quot;flame&amp;quot; shape of the wisps of cirrus in that original display. And because journalists and others who don't know any better think all things that vaguely look the same &lt;em&gt;are&lt;/em&gt; the same, the term is now applied to pretty much any colorful sky phenomenon, hence the embarrassing BBC article reporting on what &lt;em&gt;other journalists&lt;/em&gt; are calling it rather than ringing up their local meteorologist. They must have at least one in-house, no?&lt;/p&gt;&#xA;" OwnerUserId="6601" LastEditorUserId="6601" LastEditDate="2022-08-10T13:52:24.707" LastActivityDate="2022-08-10T13:52:24.707" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24122" PostTypeId="1" CreationDate="2022-08-03T20:45:36.540" Score="1" ViewCount="36" Body="&lt;p&gt;I've noticed that Environment Canada's precipitation forecasts for the Great Lakes region (east of Toronto) are usually one of the following:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;30% rain&lt;/li&gt;&#xA;&lt;li&gt;40% rain&lt;/li&gt;&#xA;&lt;li&gt;60% rain&lt;/li&gt;&#xA;&lt;li&gt;70% rain&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;But not usually higher than 70%.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Whereas, I've heard the forecast in the prairies (Winnipeg) often have a higher certainty, such as:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;80% rain&lt;/li&gt;&#xA;&lt;li&gt;90% rain&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;That makes me wonder:&lt;/p&gt;&#xA;&lt;p&gt;Is it easier to make high-certainty precipitation predictions in places like the prairies  vs. the Great Lakes region?&lt;/p&gt;&#xA;&lt;p&gt;For example, would Lake Ontario and/or the Oak Ridges Moraine make it harder to predict precipitation in the Great Lakes region — since inbound storms might be affected by those features?&lt;/p&gt;&#xA;" OwnerUserId="27359" LastActivityDate="2022-08-03T20:45:36.540" Title="Do geographic features like large lakes or a moraine make it more difficult to predict precipitation?" Tags="|weather-forecasting|precipitation|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24123" PostTypeId="1" CreationDate="2022-08-04T12:46:46.153" Score="1" ViewCount="406" Body="&lt;p&gt;I am reading about water in the Lunar mantle, however it mentions fugacity a lot. What does it mean in this context?&lt;/p&gt;&#xA;" OwnerUserId="27364" LastActivityDate="2022-08-07T17:18:26.627" Title="What does fugacity mean in the context of geology?" Tags="|geology|geochemistry|planetary-science|mantle|moon|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24126" PostTypeId="2" ParentId="1068" CreationDate="2022-08-05T02:59:20.680" Score="2" Body="&lt;p&gt;The axiom and corollary appear to have originated at a conference held in 1984 and are named after Stuart Ross Taylor, at the time affiliated with the Research School of Earth Sciences, Australian National University, Canberra.&lt;/p&gt;&#xA;&lt;p&gt;Stuart Ross Taylor, &amp;quot;The Origin of the Moon: Geochemical Considerations&amp;quot;, In W.R. Hartmann, R.J. William, and G. J Taylor (eds.), Proceedings of the Conference &lt;em&gt;Origin of the moon&lt;/em&gt;, Kona, HI, October 13-16, 1984. Houston: Lunar and Planetary Institute 1986, pp. 125-143 (&lt;a href=&quot;https://articles.adsabs.harvard.edu/full/conf/ormo./1986//0000125.000.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;scan online&lt;/a&gt;). At the end of the paper one finds:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Hypotheses in science should be testable. A test to distinguish between the two viable hypotheses of lunar origin, large impactor and double planet, can be made in principle by dating the volatile depletion event.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This statement may have triggered some discussion on the issue of testability, because a prefatory page in the conference record that I found described in Robert Malcuit, &lt;em&gt;Geoforming Mars: How could nature have made Mars more like Earth?&lt;/em&gt;, Springer 2021, &lt;a href=&quot;https://books.google.com/books?id=Y2gLEAAAQBAJ&amp;amp;pg=PA142#v=onepage&amp;amp;q&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;p. 142&lt;/a&gt;, supposedly reads as follows:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Page Before the PREFACE (Unlabeled Page VI) Has a Few Interesting Comments by at Least Two of the Participants (in Approximately the Same Format as the Page in the Book)&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;TAYLORS'S AXIOM&lt;/strong&gt;&lt;br /&gt;&#xA;The best models for lunar origin are the testable ones.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;TAYLOR's COROLLARY&lt;/strong&gt;&lt;br /&gt;&#xA;The testable models for lunar origin are wrong. — S. Ross Taylor paraphrased by Sean Solomon, at the Conference on the Origin of the Moon, Kona, 1984.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So far I have been unable to find a scan of the relevant page of the conference proceedings online to confirm this description, however I found a blog post &lt;a href=&quot;https://geologyrocks2016.wordpress.com/2016/03/28/the-genesis-of-the-moon/&quot; rel=&quot;nofollow noreferrer&quot;&gt;&amp;quot;The Genesis of the Moon&amp;quot;&lt;/a&gt; that provides matching information. Google provides merely snippet views (&lt;a href=&quot;https://www.google.com/books/edition/Origin_of_the_Moon/fJTvAAAAMAAJ?hl=en&amp;amp;gbpv=1&amp;amp;bsq=%22TAYLOR%27S%20AXIOM:%22&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;, &lt;a href=&quot;https://www.google.com/books/edition/Origin_of_the_Moon/fJTvAAAAMAAJ?hl=en&amp;amp;gbpv=1&amp;amp;bsq=%22Taylor%27s%20corollary%22%20&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;, &lt;a href=&quot;https://www.google.com/books/edition/Origin_of_the_Moon/fJTvAAAAMAAJ?hl=en&amp;amp;gbpv=1&amp;amp;bsq=%22The+testable+models+for+lunar+origin+are+wrong%22&amp;amp;dq=%22The+testable+models+for+lunar+origin+are+wrong%22&amp;amp;printsec=frontcover&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;) of page VI, just enough to confirm that this page holds the relevant information.&lt;/p&gt;&#xA;" OwnerUserId="5255" LastEditorUserId="5255" LastEditDate="2022-08-05T03:56:11.783" LastActivityDate="2022-08-05T03:56:11.783" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24127" PostTypeId="1" AcceptedAnswerId="24128" CreationDate="2022-08-05T04:32:29.500" Score="8" ViewCount="8189" Body="&lt;p&gt;I have recently taken a picture while on a walk, which is showing a phenomenon I cannot really find an explanation of.&lt;/p&gt;&#xA;&lt;p&gt;A contrail was visible in the air, backed with a dark line that went all the way to the ground. The dark line was visible only for 1 minute, the sun was directly in line with the contrail. Though my first idea was to say it is a shadow, it doesn’t really make sense to me, because I would not expect the shadow to be loosely projected into the atmosphere. Also, a contrail does not seem to be dense enough for a dense shadow like this one.&lt;/p&gt;&#xA;&lt;p&gt;The plane flying was a Boeing KC-135R Stratotanker, which can produce a large contrail with its four engines, which nevertheless could point to a shadow or weird refraction. Please help, I would like to know how this happened!&lt;/p&gt;&#xA;&lt;p&gt;Time: August 3rd, 2:40 pm&lt;/p&gt;&#xA;&lt;p&gt;Location: &lt;a href=&quot;https://goo.gl/maps/bGK9wntaSWGgNmiZ8&quot; rel=&quot;noreferrer&quot;&gt;(53.118526, 9.198616)&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4mhE5.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4mhE5.jpg&quot; alt=&quot;contrail shadow&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5G7ao.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5G7ao.jpg&quot; alt=&quot;FR24&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27368" LastEditorUserId="2470" LastEditDate="2022-08-05T05:13:54.107" LastActivityDate="2024-03-02T03:45:47.950" Title="Explanation for contrail with a dark line" Tags="|atmospheric-optics|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24128" PostTypeId="2" ParentId="24127" CreationDate="2022-08-05T11:38:57.720" Score="13" Body="&lt;p&gt;You happened to be in the right place at the right time and the plane happened to be flying in just the right direction at that time. What you saw was the plane flying parallel to the shadow of its contrail.&lt;/p&gt;&#xA;&lt;p&gt;Note that the contrail broadens a bit toward the top of the photograph. That's the older part of the contrail. The plane is located at the lowest white portion of the contrail. The part below that is the volumetric shadow of the contrail. That portion of the sky was relatively unlit compared to other parts of the sky, thereby causing the Rayleigh scattering that makes sky blue to be somewhat subdued. Because the plane was flying in just the right direction (flying to the northeast when the Sun was to the southwest), the shadow of the contrail was greatly enhanced.&lt;/p&gt;&#xA;&lt;p&gt;Here's another image of a volumetric shadow of a human-made cloud, this time from the post-sunset launch of STS-98. In this image, the sun has already set on the ground, but has not yet set from higher altitudes. The very thick contrail of a Shuttle launch is well-lit higher up, and its volumetric shadow points right at the Moon. The Moon is close to full in this image, placing it very close to the anti-solar point. The anti-solar point is where parallel shadows appear to converge.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/c/c7/Atlantis_launch_plume_edit.jpg/716px-Atlantis_launch_plume_edit.jpg&quot; alt=&quot;Striking image of STS-98 launch, with volumetric shadow of the exhaust appearing to intersect the Moon&quot; /&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2022-08-05T11:46:24.150" LastActivityDate="2022-08-05T11:46:24.150" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24129" PostTypeId="1" CreationDate="2022-08-05T15:01:40.820" Score="3" ViewCount="140" Body="&lt;p&gt;A formula was given by Brian Norcross but I wanted to know what others thought of this formula:&lt;/p&gt;&#xA;&lt;p&gt;Hurricane Sustained Winds (mph) = 9.615 * (1015.8 - central pressure [mb])&lt;sup&gt;0.6143&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="27233" LastEditorUserId="6298" LastEditDate="2022-08-07T05:33:32.423" LastActivityDate="2022-08-07T17:41:35.493" Title="How to estimate a hurricane's wind speed in mph from other factors?" Tags="|meteorology|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24131" PostTypeId="2" ParentId="24064" CreationDate="2022-08-06T00:45:45.550" Score="3" Body="&lt;p&gt;The real oceans on Earth have a majority of their surface area (53% of the total ocean area) in the abyssal range &lt;a href=&quot;https://doi.org/10.1081/E-ENRW-120048589&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9vxW0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9vxW0.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Dierssen, Heidi &amp;amp; Theberge, Albert. (2014). &amp;quot;Bathymetry: Features and Hypsography.&amp;quot; &lt;a href=&quot;https://doi.org/10.1081/E-ENRW-120048589&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1081/E-ENRW-120048589&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2022-08-06T00:53:26.473" LastActivityDate="2022-08-06T00:53:26.473" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24132" PostTypeId="1" AcceptedAnswerId="24141" CreationDate="2022-08-06T04:41:48.357" Score="2" ViewCount="111" Body="&lt;p&gt;I am trying to study about forest biomass and carbon amount of forest.&#xA;First of all, I studied some papers, they mentioned that age of forest is related to the biomass. So, How do we measure the age of tree? What are the practical ways used to estimate tree age?&lt;/p&gt;&#xA;" OwnerUserId="27378" LastEditorUserId="18081" LastEditDate="2022-08-06T08:21:31.190" LastActivityDate="2022-08-08T09:53:42.353" Title="How is tree age estimated?" Tags="|remote-sensing|forest|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24135" PostTypeId="1" CreationDate="2022-08-06T22:09:50.150" Score="2" ViewCount="23" Body="&lt;p&gt;The following differential equation allows me to calculate the the number concentration of aerosol particles from 2 nm to 3 nm.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{dN_2{_-{_3}}}{dt}=J_2-J_3-N_2{_-{_3}}.CoagS_2{_-{_3}}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;In the above equation, &lt;span class=&quot;math-container&quot;&gt;$\frac{dN_2{_-{_3}}}{dt}$&lt;/span&gt; is the rate of change of number concentration of the aerosol particles in &lt;span class=&quot;math-container&quot;&gt;$cm^-{^3}s^-{^1}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$J_2$&lt;/span&gt; is the formation rate of atmospheric particles at 2 nm in &lt;span class=&quot;math-container&quot;&gt;$cm^-{^3}s^-{^1}$&lt;/span&gt;,  &lt;span class=&quot;math-container&quot;&gt;$J_3$&lt;/span&gt; is the formation rate of atmospheric particles at 3 nm in &lt;span class=&quot;math-container&quot;&gt;$cm^-{^3}s^-{^1}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$N_2{_-{_3}}$&lt;/span&gt; is the number concentration of particles in &lt;span class=&quot;math-container&quot;&gt;$cm^-{^3}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$CoagS_2{_-{_3}}$&lt;/span&gt; is the coagulstion sink of the aerosol particles from 2-3 nm in &lt;span class=&quot;math-container&quot;&gt;$s^-{^1}$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;If we assume a pseudo steady-state between the sources and sinks of 2-3 nm atmospheric molecular clusters, then: &lt;span class=&quot;math-container&quot;&gt;$$\frac{dN_2{_-{_3}}}{dt}=0$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;A consequence of this is:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$N_2{_-{_3}}=\frac{J_2-J_3-N_2{_-{_3}}}{CoagS_2{_-{_3}}}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Number concentration of aerosol particles due to primary emissions are known to increase at larger aerosol particle sizes. Therefore, &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0021850221006078&quot; rel=&quot;nofollow noreferrer&quot;&gt;(Kulmala et al., 2021)&lt;/a&gt; states that by using a higher value of 25 nm instead of 3 nm as the upper interval bound &lt;span class=&quot;math-container&quot;&gt;$d_2$&lt;/span&gt;, which is the upper interval bound aerosol particle diameter in nm, for the calculation of &lt;span class=&quot;math-container&quot;&gt;$J_2$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$J_3$&lt;/span&gt;, the influence of primary emissions on &lt;span class=&quot;math-container&quot;&gt;$N_2{_-{_3}}$&lt;/span&gt; are reduced. The apparent logic of taking a larger size interval for the calculation of &lt;span class=&quot;math-container&quot;&gt;$J_2{_-{_3}}$&lt;/span&gt; is that the increase in the primary emissions at larger sizes are offsetting the formation rate at both the lower interval bound &lt;span class=&quot;math-container&quot;&gt;$d_1$&lt;/span&gt; and the upper interval bound &lt;span class=&quot;math-container&quot;&gt;$d_2$&lt;/span&gt;. Although, in terms of absolute numbers, the calculated values of &lt;span class=&quot;math-container&quot;&gt;$J_2$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$J_3$&lt;/span&gt; would be less accurate using this larger size interval. Mathematically:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$N_2{_-{_3}}=N_2{_-{_2{_5}}}-N_3{_-{_2{_5}}}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Could someone explain to me, mathematically, how is choosing a higher value of 25 nm instead of 3 nm as the upper interval bound &lt;span class=&quot;math-container&quot;&gt;$d_2$&lt;/span&gt; to calculate &lt;span class=&quot;math-container&quot;&gt;$N_2{_-{_3}}$&lt;/span&gt;, offsetting the formation rate at both the lower interval bound &lt;span class=&quot;math-container&quot;&gt;$d_1$&lt;/span&gt;, 2 nm, and the upper interval bound &lt;span class=&quot;math-container&quot;&gt;$d_2$&lt;/span&gt;, 3 nm?&lt;/p&gt;&#xA;" OwnerUserId="27385" LastEditorUserId="27385" LastEditDate="2022-08-06T22:29:16.157" LastActivityDate="2022-08-06T22:29:16.157" Title="What is the effect of increasing the size interval in the generalized dynamic equation (GDE) to simulate an evolving aerosol?" Tags="|meteorology|models|aerosol|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24136" PostTypeId="2" ParentId="24129" CreationDate="2022-08-07T07:32:03.290" Score="3" Body="&lt;p&gt;Calculating the formula's average absolute error percentage with the &lt;a href=&quot;https://www.ncei.noaa.gov/access/metadata/landing-page/bin/iso?id=gov.noaa.ncdc:C00834&quot; rel=&quot;nofollow noreferrer&quot;&gt;best-track CSV archive&lt;/a&gt; for the Atlantic basin gave values of:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/siC45.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/siC45.png&quot; alt=&quot;formula errors&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Which shows both that it is somewhat reasonable, and that its skill is still fairly limited.&lt;/p&gt;&#xA;&lt;p&gt;Such a simplistic formula would fail to account for surrounding pressures, storm structure, and things like extratropical transition.  If I remember right, there is usually a time lag, as wind speed changes more quickly (particularly after landfall!) compared to pressure, as the storm and its warm core structure take time to respond to local changes.  Also, storms that are subtropical or undergoing extratropical transition have an increased chance of having dynamics-caused wind maxima far removed from the MSLP center.  Those reasons line up with the greater error in the columns for subtropical systems and tropical depressions (and it also looks like in skimming through the full results that there is probably larger errors later in a storm's life)&lt;/p&gt;&#xA;&lt;p&gt;The applicability of this formula would be challenging... because we can't know the true minimum central pressure without direct observations anyways.  You could use it when looking at models... but they're already just models, so it doesn't seem there's good reason to get precise with windspeed guesses. The models forecast wind as well. Model wind speed forecasts often won't line up with reality due to resolution and continuity constraints, but that's true of MSLP estimates as well.&lt;/p&gt;&#xA;&lt;p&gt;And we already have solid, well-refined options for analyzing storms when direct observations (like NOAA aircraft with their scatterometers, aircraft radar, and dropwindsondes to much better investigate reality... or stations/buoys/land-based radars) are limited: &lt;a href=&quot;https://www.nhc.noaa.gov/pdf/06velden.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Dvorak Technique&lt;/a&gt;, which uses satellite presentation and trends to estimate the intensity.  &lt;a href=&quot;https://journals.ametsoc.org/view/journals/wefo/25/5/2010waf2222375_1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;An Evaluation of Dvorak Technique–Based Tropical Cyclone Intensity Estimates by Knaff et al.&lt;/a&gt; shows Dvorak errors (by comparing to storms with recon data) continue to average less than 10 knots.&lt;/p&gt;&#xA;&lt;p&gt;So in the end the formula is just a novelty exercise to try to find a way to hyper-simplify complex things (similar to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/16366/weather-forecast-based-on-pressure-temperature-and-humidity-only-for-implement&quot;&gt;this SE question on forecasting the weather&lt;/a&gt;), and simply verifies that lower local pressures do tend towards greater winds (as would make sense from the full &lt;a href=&quot;https://en.wikipedia.org/wiki/Navier%E2%80%93Stokes_equations#:%7E:text=The%20Navier%E2%80%93Stokes%20equations%20mathematically,relating%20pressure%2C%20temperature%20and%20density.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Navier-Stokes equations&lt;/a&gt;, as they have the &lt;a href=&quot;https://www.youtube.com/watch?v=EF2mv8-48Uo&quot; rel=&quot;nofollow noreferrer&quot;&gt;pressure gradient force terms, and lower pressures tend to mean more pressure gradient&lt;/a&gt;).  But not sure it has extensive applications.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-08-07T17:41:35.493" LastActivityDate="2022-08-07T17:41:35.493" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24137" PostTypeId="1" AcceptedAnswerId="24330" CreationDate="2022-08-07T08:55:14.270" Score="1" ViewCount="86" Body="&lt;p&gt;The heatwave that hit Europe in July was not only highly unpleasant (40°C), but has been predicted to be an exceptionally onerous medical, agricultural and economic burden. As someone outside of the field, I was wondering why attempts involving stratospheric aerosol releases to combat heatwaves in southern Europe are not discussed. The Wikipedia article on &lt;a href=&quot;https://en.wikipedia.org/wiki/Stratospheric_aerosol_injection&quot; rel=&quot;nofollow noreferrer&quot;&gt;stratospheric aerosol injection&lt;/a&gt; lists several real, possible and perceived drawbacks, but focuses on it as an impractically expensive global solution as opposed to being used temporarily to reduce heatwaves.  Despite extrapolations from a 2006 Californian heatwave test of a reduction of 7°C &lt;a href=&quot;https://acp.copernicus.org/articles/13/6373/2013/&quot; rel=&quot;nofollow noreferrer&quot;&gt;[ref]&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Is the &lt;em&gt;lack of discussion on temporary regional usage of aerosol injection for heatwaves&lt;/em&gt; simply caused by non-technical factors like:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;a lack of political willpower (as the Extinction Rebellion protests in the UK and petitions such as &lt;a href=&quot;https://www.change.org/p/un-voto-per-il-clima&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one&lt;/a&gt; suggest)&lt;/li&gt;&#xA;&lt;li&gt;ethical objections (e.g. we should save wildlife and cut pollution&#xA;rather than engineer the climate)&lt;/li&gt;&#xA;&lt;li&gt;its cost and lack of awareness outside of scientific circles (the aforementioned Wikipedia page is &lt;a href=&quot;https://pageviews.wmcloud.org/?project=en.wikipedia.org&amp;amp;platform=all-access&amp;amp;agent=user&amp;amp;redirects=0&amp;amp;start=2021-08-01&amp;amp;end=2022-07-31&amp;amp;pages=Stratospheric_aerosol_injection%7CSnowpiercer_(TV_series)&quot; rel=&quot;nofollow noreferrer&quot;&gt;visited only 200 times a day, ten fold less than Snowpiercer&lt;/a&gt;, a post-apocalyptic Netflix show with it as a wild premise)&lt;/li&gt;&#xA;&lt;li&gt;its experimental state (even if it was tested 16 years ago with some success —as far as I can tell)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Or is the reason technical: from what I understand European heatwaves are caused by anticyclones from Africa (or at least the meteorological offices give these media friendly names like Charon, Scipio or Hannibal) so the solar irradiation was not originally collected in the affected areas (but in the Sahara) so aerosol injections would not work (or worse would trap the heat at night or exacerbate the anti-cyclone)?&lt;/p&gt;&#xA;&lt;p&gt;What is holding back this option?&lt;/p&gt;&#xA;&lt;hr&gt;&#xA;&lt;p&gt;&lt;em&gt;Footnote.&lt;/em&gt; there's a related &lt;a href=&quot;https://earthscience.stackexchange.com/questions/24054/could-stratospheric-aerosol-injection-be-used-to-fine-tune-climate-locally&quot;&gt;Q here&lt;/a&gt;, but it's both unanswered and broad. I am more interested in Europe and heatwaves, hence my opening a new Q.&lt;/p&gt;&#xA;" OwnerUserId="18400" LastEditorUserId="6298" LastEditDate="2022-08-07T19:56:18.047" LastActivityDate="2022-09-16T11:20:43.377" Title="Aerosol injections to manage European heatwaves?" Tags="|climate-change|geoengineering|cyclone|aerosol|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24138" PostTypeId="2" ParentId="24123" CreationDate="2022-08-07T17:09:44.720" Score="1" Body="&lt;p&gt;'Fugacity' is effectively the equivalent of chemical activity, but for gases. Fugacity relates to the partial pressure of a particular volatile component of a system in the same way that chemical activity relates to the concentration of a given chemical phase.&lt;/p&gt;&#xA;&lt;p&gt;Most often in geology, this will refer to 'fugacity of oxygen (&lt;em&gt;f&lt;/em&gt;O&lt;sub&gt;2&lt;/sub&gt;)' in a system - this is effectively a measure of how reactive oxygen is, and thus how oxidized a given system will be, usually with respect to the minerals that are stable in them.&lt;/p&gt;&#xA;&lt;p&gt;At temperatures that most mantle processes operate on, aqueous fluid phases generally exist in a supercritical state, which we also apply the concept of fugacity to. So, if the text you are reading states something about 'fugacity of H&lt;sub&gt;2&lt;/sub&gt;O', then it is likely referring to the reactivity of supercritical water vapor in the lunar mantle system.&lt;/p&gt;&#xA;" OwnerUserId="27389" LastEditorUserId="2470" LastEditDate="2022-08-07T17:18:26.627" LastActivityDate="2022-08-07T17:18:26.627" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24139" PostTypeId="2" ParentId="22966" CreationDate="2022-08-07T18:00:34.250" Score="4" Body="&lt;p&gt;I will preface this by saying that I am not particularly familiar with radiocarbon dating techniques, and therefore the minutiae are somewhat lost on me. However, as someone who works with several other radiometric dating systems, nothing this guy says is outright untrue, but it would seem like he is exaggerating their consequences to paint all carbon dating as some sort of nefarious conspiracy.&lt;/p&gt;&#xA;&lt;p&gt;Assumptions are inherent to &lt;em&gt;all radiometric dating techniques&lt;/em&gt;. This includes things as fundamental as the idea that radioactive isotope decay rates are constant throughout time, all the way to things that vary depending on the specific geochronometer, like closure criteria for the isotope pair in question for a particular mineral. In the case of carbon dating, we assume that the isotopic ratios are 'locked in' as soon as the material being dated stops actively exchanging carbon with the atmosphere (i.e., in some applications, dies), and accordingly that this is the time reflected by the carbon date.&lt;/p&gt;&#xA;&lt;p&gt;Where this guy has lost the plot a bit is in his presumption of malice - &lt;em&gt;nobody is claiming that carbon dating is infallible&lt;/em&gt;. Media reports may paint carbon dates as absolute - as they do with all scientific conclusions from nutrition to medicine and so on - but that is the media's doing, and any good scientist will readily concede that there are caveats to the ages they assign to a dated material. We are constantly iterating on and improving the techniques we use - carbon dating even generally reports results based on two half-lives, just to keep consistent with studies that pre-date the recalibration of the &lt;sup&gt;14&lt;/sup&gt;C decay constant: &lt;a href=&quot;https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Nuclear_Chemistry/Applications_of_Nuclear_Chemistry/Radiocarbon_Dating&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://chem.libretexts.org/Bookshelves/Physical_and_Theoretical_Chemistry_Textbook_Maps/Supplemental_Modules_(Physical_and_Theoretical_Chemistry)/Nuclear_Chemistry/Applications_of_Nuclear_Chemistry/Radiocarbon_Dating&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Not really the kind of limitation you would expect the architects of a conspiracy to cop to so easily.&lt;/p&gt;&#xA;&lt;p&gt;What's more, the effects of the 'secret' problems he claims render carbon dating pointless would not be big enough to validate whatever scheme he thinks is being pulled. At most, carbon dates in the future may change by several hundred years as our assumptions become more precise. Obviously this is quite a lot, especially if you are trying to attribute an artifact to a specific civilization - but probably not enough to demonstrate whatever 'big lie' he claims is being perpetrated by the evil carbon dating community.&lt;/p&gt;&#xA;" OwnerUserId="27389" LastActivityDate="2022-08-07T18:00:34.250" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24140" PostTypeId="2" ParentId="8798" CreationDate="2022-08-07T21:52:53.373" Score="4" Body="&lt;p&gt;We might also consider minerals that cannot appear as minerals on Earth because Earth is too hot. These would be ices that exist in solid form, and meet the standard definition of minerals, mostly from roughly the orbit of Jupiter (or maybe some asteroids) outwards.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Water ice&lt;/strong&gt; does occur on Earth but is much more abundant on outer Solar System moons and other objects such as the mountains of Pluto. This category includes high-pressure ice phases such as Ice III, Ice V, or Ice VI that may occur underground on moons such as Ganymede but are unknown on Earth (Ice VII is known on Earth).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Carbon dioxide ice&lt;/strong&gt; is well-known on the polar caps of Mars.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Sulfur oxides&lt;/strong&gt;, such as sulfur dioxide and possibly more exotic oxides such as &lt;a href=&quot;https://en.wikipedia.org/wiki/Disulfur_monoxide&quot; rel=&quot;nofollow noreferrer&quot;&gt;disulfur monoxide&lt;/a&gt; (&amp;quot;It is believed that Pele on [Jupiter's moon] Io is surrounded by solid &lt;span class=&quot;math-container&quot;&gt;$\text{S}_2\text{O}$&lt;/span&gt;.&lt;a href=&quot;https://doi.org/10.1006/icar.1998.5930&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;&amp;quot;). Such oxides would likely be oxidized in Earth's atmosphere and end up as sulfates, but may condense in the colder and oxygen-free conditions at the surface of Io.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Hydrocarbons&lt;/strong&gt; are well-known on outer Solar-System bodies, often polymerizing to give &lt;a href=&quot;https://en.wikipedia.org/wiki/Tholin&quot; rel=&quot;nofollow noreferrer&quot;&gt;tholins&lt;/a&gt; and their characteristic reddish colors. Among the many objects containing tholins on the surface are Saturn's large moon Titan, Pluto and its large moon Charon, and Arrokoth &lt;a href=&quot;http://pluto.jhuapl.edu/Galleries/Featured-Images/image.php?gallery_id=2&amp;amp;image_id=606&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/x5IrS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/x5IrS.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;From Ref. &lt;a href=&quot;https://i.stack.imgur.com/i3rRw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;: the red, tholin-bearing surface of Arrokoth.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Nitrogen, carbon monoxide and methane ices&lt;/strong&gt; are found on very low-temperature surfaces. Famous examples include the nitrogen-bearing bluish band on Neptune's large moon Triton &lt;a href=&quot;https://www.nasa.gov/multimedia/imagegallery/image_feature_1706.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt; and the the ices on &lt;a href=&quot;https://en.wikipedia.org/wiki/Pluto&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pluto&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Nitrogen and carbon monoxide are most abundant on the anti-Charon face of Pluto (around 180° longitude, where Tombaugh Regio's western lobe, Sputnik Planitia, is located), whereas methane is most abundant near 30° east.&lt;a href=&quot;https://doi.org/10.1016/j.icarus.2013.01.019&quot; rel=&quot;nofollow noreferrer&quot;&gt;4&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LPCB2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LPCB2.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;From Ref. &lt;a href=&quot;https://i.stack.imgur.com/LPCB2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;: Triton with its bluish nitrogen ice belt.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/v4gaJ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/v4gaJ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;From Ref. &lt;a href=&quot;https://www.nasa.gov/feature/five-years-after-new-horizons-historic-flyby-here-are-10-cool-things-we-learned-about-plut-0&quot; rel=&quot;nofollow noreferrer&quot;&gt;[5]&lt;/a&gt;: Nitrogen and carbon monoxide rich ices in Pluto's heart, flanked by tholins on the left.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Zolotov, Mikhail Yu.; Fegley, Bruce (9 March 1998). &amp;quot;Volcanic Origin of Disulfur Monoxide (S2O) on Io&amp;quot; (PDF). &lt;em&gt;Icarus.&lt;/em&gt; &lt;strong&gt;133&lt;/strong&gt; (2): 293. Bibcode:1998Icar..133..293Z. doi:10.1006/icar.1998.5930.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;http://pluto.jhuapl.edu/Galleries/Featured-Images/image.php?gallery_id=2&amp;amp;image_id=606&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://pluto.jhuapl.edu/Galleries/Featured-Images/image.php?gallery_id=2&amp;amp;image_id=606&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.nasa.gov/multimedia/imagegallery/image_feature_1706.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nasa.gov/multimedia/imagegallery/image_feature_1706.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Grundy, W. M.; Olkin, C. B.; Young, L. A.; Buie, M. W.; Young, E. F. (2013). &amp;quot;Near-infrared spectral monitoring of Pluto's ices: Spatial distribution and secular evolution&amp;quot; (PDF). &lt;em&gt;Icarus.&lt;/em&gt; 223 (2): 710–721. arXiv:1301.6284. Bibcode:2013Icar..223..710G. &lt;a href=&quot;https://doi.org/10.1016/j.icarus.2013.01.019&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/j.icarus.2013.01.019&lt;/a&gt;. S2CID 26293543. Archived from the original (PDF) on November 8, 2015.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.nasa.gov/feature/five-years-after-new-horizons-historic-flyby-here-are-10-cool-things-we-learned-about-plut-0&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nasa.gov/feature/five-years-after-new-horizons-historic-flyby-here-are-10-cool-things-we-learned-about-plut-0&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2023-06-01T20:09:54.143" LastActivityDate="2023-06-01T20:09:54.143" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24141" PostTypeId="2" ParentId="24132" CreationDate="2022-08-08T09:53:42.353" Score="1" Body="&lt;p&gt;Biomass itself isn't a great measure of tree age because the size of a tree is affected by a number of factors. Assuming the same species of tree:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Soil nutrients: more nutrients in general means better growth for most species&lt;/li&gt;&#xA;&lt;li&gt;Availability of water: scare water means less growth&lt;/li&gt;&#xA;&lt;li&gt;Availability of light: a tree with more light grows more than one that's constrained&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;A tree with good soil, lots of water and light will grow more than one without those things, so the same age of tree could be very different sizes and biomasses. The only way to get an exact age of a tree is to get a core sample or cut it down and count the rings, every ring represents a growing year. A tree that grows very little will have narrowly spaced rings, a tree that grows a lot has wider space rings as it's putting more biomass. Note that wood density is also an important measurement for biomass, the denser the wood the more biomass is compacted in the same amount of space. Slower growing trees tend to be more dense, tree twice the size of another may not be twice the mass.&lt;/p&gt;&#xA;&lt;p&gt;That's for a single tree, but you're asking about forests. It's impractical to core sample a million trees, but you can core sample a fair number of live ones or take samples of fallen ones. Along with measurements of circumference and height you can build a database and estimate the average age of the rest of the trees in the forest from their heights and circumferences. It's also possible to estimate the biomass of the forest from estimating the number of trees in and using an average biomass.&lt;/p&gt;&#xA;" OwnerUserId="27024" LastActivityDate="2022-08-08T09:53:42.353" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24143" PostTypeId="2" ParentId="24052" CreationDate="2022-08-09T00:33:21.953" Score="1" Body="&lt;p&gt;Svante Arhennius' crude calculations published in 1896 of the likely global temperature changes from halving and doubling CO2 (based on prior work by Tyndall, Foote and Fourier) were considered speculative - amongst other speculations about climate - and were not taken seriously at the time or for a long time after. In part because the prevailing view was nothing humans could do could change the climate but also, in science terms, through incorrect understandings around &amp;quot;saturation&amp;quot; of Infrared absorption and ocean uptake (drawdown?) of CO2.&lt;/p&gt;&#xA;&lt;p&gt;The re-emission of IR from greenhouse gas molecules within the atmosphere was not fully accounted for, leading to the incorrect conclusion that with enough CO2 to catch 100% of IR on the way to space adding more would make no difference.&lt;/p&gt;&#xA;&lt;p&gt;With respect to ocean uptake of CO2, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Revelle_factor&quot; rel=&quot;nofollow noreferrer&quot;&gt;Revelle Factor&lt;/a&gt; - resistance of the ocean surface layer to taking in CO2 - was not known until 1957; it was assumed rapid ocean uptake would prevent CO2 concentrations rising significantly in the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;By the early 1970's most factors that are now deemed capable of causing &amp;quot;inadvertent climate modification&amp;quot; were known - including that aerosols from fossil fuel burning had a reflective effect that reduced solar intensity, ie a cooling influence - but not it's relative strength over time compared to enhanced greenhouse effect. The relative strengths of all the known factors and the impacts of interactions and feedbacks within the global climate system were not known with sufficient precision for it to be possible to be sure, even into the 1970's.&lt;/p&gt;&#xA;&lt;p&gt;From &amp;quot;Understanding Climatic Change: a Program for Action&amp;quot; - US National Academy of Sciences, 1975 -&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;Unfortunately, we do not have a good quantitative understanding of&#xA;our climate machine and what determines its course. Without this&#xA;fundamental understanding, it does not seem possible to predict&#xA;climate — neither in its short-term variations nor in its larger&#xA;long-term changes.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The &amp;quot;Program for Action&amp;quot; was intended to achieve that better &amp;quot;quantitative understanding&amp;quot; and by the 1980's had done so well enough for then still current &amp;quot;little ice age&amp;quot; fears to be put to rest. Unfortunately the reason why - warming was expected to dominate - was not so reassuring as was hoped.&lt;/p&gt;&#xA;&lt;p&gt;A lot of debate and dispute has followed but every high level science based report and study from the world's leading science and climate science institutions since then (about 4 decades so far) has consistently concluded that we have global warming and can expect more so long as we keep burning fossil fuels and adding CO2 (and methane) to the atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="18145" LastEditDate="2022-08-09T01:38:47.247" LastActivityDate="2022-08-09T01:38:47.247" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24145" PostTypeId="1" CreationDate="2022-08-09T18:01:21.230" Score="1" ViewCount="168" Body="&lt;p&gt;What is a Poisson solid and what affect does it have on p and s waves?&lt;/p&gt;&#xA;" OwnerUserId="27398" LastEditorUserId="2470" LastEditDate="2022-08-10T00:26:09.843" LastActivityDate="2022-08-10T00:26:09.843" Title="What is a Poisson solid and what affect does it have on p and s waves?" Tags="|geology|geophysics|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24148" PostTypeId="1" AcceptedAnswerId="24149" CreationDate="2022-08-10T09:33:40.037" Score="0" ViewCount="61" Body="&lt;p&gt;I'm just finishing my Bachelor's degree in Geochemistry at a German university and will soon start my Master's degree, but I've been wondering for a few weeks whether a stay abroad (1 semester or even 1 year) is important and when it's best to do it. In other words, should I do it during my Master's degree or during my dissertation?&lt;/p&gt;&#xA;&lt;p&gt;What are your experiences, or has an experience abroad been important for your academic career?&lt;/p&gt;&#xA;&lt;p&gt;I am aware that this question can be closed because of Option Based/OFF TOPIC. But I also didn't want to ask this question on Earth Science Meta, because this question doesn't fit there either!&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2022-08-10T13:38:43.383" Title="Is experience abroad important for your career?" Tags="|geochemistry|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24149" PostTypeId="2" ParentId="24148" CreationDate="2022-08-10T13:38:43.383" Score="1" Body="&lt;p&gt;As a perspective from an oceanographer, in the hiring process, academic institutions definitely take into account your time abroad and collaborations you've cultivated along the way. If you're intending on doing a PhD, I would suggest that this would be the best time for you to pursue your studies/research abroad.&lt;/p&gt;&#xA;" OwnerUserId="27402" LastActivityDate="2022-08-10T13:38:43.383" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24150" PostTypeId="1" CreationDate="2022-08-11T16:38:54.760" Score="6" ViewCount="74" Body="&lt;p&gt;I would like to get access to a time series of data on atmospheric pressure over a short timescale. I need to get a feel for how much variation there is over seconds and minutes, so a data point every second for an hour would be great, but anything in that direction would help. Ideally for a temperate (UK) climate, but anything would help.&lt;/p&gt;&#xA;&lt;p&gt;In no sense am I an Earth Science person - I am an electronic engineer, developing an augmented reality device to train surgeons in a new surgical procedure. I'm getting some hard to explain results, and after eliminating some obvious and some not-so-obvious possible causes, I remain a bit baffled. Fluctuations in atmospheric pressure interfering with pressure readings within a supposedly closed, rigid, system are about the final thing I can think of. Any help would be greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="27408" LastActivityDate="2023-01-12T08:02:40.377" Title="Atmospheric pressure: intra-day time series" Tags="|measurements|pressure|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24151" PostTypeId="1" CreationDate="2022-08-11T19:54:23.017" Score="2" ViewCount="980" Body="&lt;p&gt;In this &lt;a href=&quot;https://www.youtube.com/watch?v=i4Hnv_ZJSQY&amp;amp;ab_channel=Freethink&quot; rel=&quot;nofollow noreferrer&quot;&gt;youtube video&lt;/a&gt; American entrepreneur Russ George claims  that - based on research of oceanographer  John Martin  and some experiments he made in British Columbia - pouring mineral dust into the ocean will make the plankton bloom  and in turn it will allow the ocean to remove the vast majority of humanity carbon dioxide from the atmosphere.&#xA;He says that the amount of mineral dust (iron ore rock dust) required is in the order of the hundreds of thousands of tons.&lt;/p&gt;&#xA;&lt;p&gt;He claims that this process will mitigate climate change in a matter of years and it will cost some millions of dollars.&#xA;He says that this process (that he calls 'Ocean pasture restoration') is capable to pull 30/35 billions of tons of carbon dioxide out of the atmosphere every year while humanity produces 45 billions of tons of carbon dioxide de every year.&lt;/p&gt;&#xA;&lt;p&gt;Is this a real solution to climate change as this person claims or not?&lt;/p&gt;&#xA;" OwnerUserId="27059" LastActivityDate="2024-03-03T02:06:40.787" Title="Is ocean pasture restoration a real solution to quickly mitigate climate change?" Tags="|climate-change|oceanography|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24152" PostTypeId="1" CreationDate="2022-08-12T03:59:41.210" Score="1" ViewCount="51" Body="&lt;p&gt;Growing food in deserts with seawater seems to be a way to feed people and revitalize a ravished landscape. &lt;a href=&quot;https://www.youtube.com/watch?v=PvV-iPdORLc&quot; rel=&quot;nofollow noreferrer&quot;&gt;They appear to be doing it already&lt;/a&gt;. Why can't We pipe some ocean water inland from the West Coast to do the same?&lt;/p&gt;&#xA;" OwnerUserId="27414" LastEditorUserId="26841" LastEditDate="2022-08-12T09:27:53.997" LastActivityDate="2022-08-12T09:27:53.997" Title="Has this Science improved since 2018" Tags="|oceanography|agriculture|desertification|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24153" PostTypeId="2" ParentId="24151" CreationDate="2022-08-12T08:19:11.710" Score="0" Body="&lt;p&gt;This concept would be tantamount to fertilising the oceans. Yes you can do this, as a result there would be so much primary producers that when they decompose all the O2 is pulled out of the oceans (mass extinction occurs). When there is no more O2, the primary producers sink to the bottom of the ocean with the bound CO2. So in the long run this would lower the CO2 level but the consequences of this method would be a mass extinction. I could not imagine a way to control this as a human being.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2022-08-12T08:19:11.710" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24154" PostTypeId="1" CreationDate="2022-08-12T09:56:11.380" Score="0" ViewCount="61" Body="&lt;p&gt;Hello I am looking for a map that shows the typical (typical for the last 50 years) precipitation paths in the Northern Hemisphere! I already know this &lt;a href=&quot;http://tropic.ssec.wisc.edu/real-time/mtpw2/product.php?color_type=tpw_nrl_colors&amp;amp;prod=global2&amp;amp;timespan=120hrs&amp;amp;anim=html5&quot; rel=&quot;nofollow noreferrer&quot;&gt;map&lt;/a&gt;, but it only shows a momentary event and does not help me any further.&lt;/p&gt;&#xA;&lt;p&gt;EDIT:&#xA;EG. I mean typical rain paths, such as the water masses for Europe evaporating in the Central Atlantic and then being &amp;quot;pushed&amp;quot; towards Europe between the Azores high and the Icelandic low.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-09-14T08:31:42.250" LastActivityDate="2022-09-14T08:31:42.250" Title="Map showing the typical rainfall paths" Tags="|meteorology|mapping|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24155" PostTypeId="1" CreationDate="2022-08-12T10:39:08.540" Score="2" ViewCount="45" Body="&lt;p&gt;I would like to include wetlands and riparian zones as hydrological response units (HRUs) within the agricultural catchment research unit (ACRU4) model. In the ACRU4 user manual there are graphical representations showing how one would typically conceptualize the riparian zone and wetland within the model. However, it is unclear as to how a user should specify that when stream/river bank full discharge is exceeded, water will spill onto the riparian zone or wetland. Please can someone specify how this is done?&lt;/p&gt;&#xA;" OwnerUserId="27337" LastEditorUserId="27337" LastEditDate="2022-08-24T06:42:15.597" LastActivityDate="2022-08-24T06:42:15.597" Title="ACRU4 riparian zone receiving flood water from river channel" Tags="|hydrology|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24156" PostTypeId="1" CreationDate="2022-08-12T10:47:43.040" Score="2" ViewCount="3356" Body="&lt;p&gt;for ERA5 hourly data on single level relative humidity can not be downloaded. However, dewpoint temperature is given and in the description it is stated that &amp;quot;combined with temperature and pressure, it can be used to calculate the relative humidity&amp;quot;. After some research I only found formulas that take temperature but not pressure into account. Could you maybe help me how I calculate relative humidity taking all the variables temperature, dewpoint temperature and surface pressure into account?&#xA;Thank you so much in advance&lt;/p&gt;&#xA;" OwnerUserId="27416" LastActivityDate="2023-10-12T13:46:14.047" Title="ERA5 Single Level - Calculate relative humidity" Tags="|climate|humidity|reanalysis|era|pressure|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24158" PostTypeId="2" ParentId="24155" CreationDate="2022-08-12T10:59:24.853" Score="1" Body="&lt;p&gt;All that you need to do is define the ChannelFlowCapacity (CAPM3S) variable.  It can be difficult to know what value to use for this variable, however, for example, you could make an estimate of how often the wetland receives flood water from the channel and then look at the flow time series and determine the appropriate flow value for the variable.&lt;br /&gt;&#xA;Alternatively, you could set a very low value for the variable so that the wetland stays wet most of the time.&lt;/p&gt;&#xA;" OwnerUserId="27363" LastActivityDate="2022-08-12T10:59:24.853" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24159" PostTypeId="1" CreationDate="2022-08-13T16:27:28.297" Score="3" ViewCount="103" Body="&lt;p&gt;context: the models that simulate the flow of water in the soil (e.g. land-surface models)&lt;/p&gt;&#xA;&lt;p&gt;In these models, in order to simulate percolation (/drainage) from the bottom of the defined soil column, we need to define a lower boundary condition. The two options which I see in the literature are a seepage face (SF) and a unit gradient condition.&lt;/p&gt;&#xA;&lt;p&gt;Is it correct to define these two as the following:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;SF: percolation happens only if the last layer in the soil column is saturated.&lt;/li&gt;&#xA;&lt;li&gt;UG: percolation happens only if the soil water content at the bottom of the column is greater than the soil water content at the field capacity.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I have been told that since SF and UG are defined based on suction and not soil moisture, the above definitions are not technically correct.&lt;/p&gt;&#xA;&lt;p&gt;Please let me know what you think, thanks in advance.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;more context:&#xA;the model calculates the percolation from the bottom of the soil column using the 1D Darcian flow equation, triggered by a water content value (of the last layer) threshold. That is why I need to define the lower boundary based on water content.&lt;/p&gt;&#xA;" OwnerUserId="20807" LastEditorUserId="20807" LastEditDate="2022-08-15T16:58:48.010" LastActivityDate="2022-12-09T05:54:09.010" Title="How to define the lower boundary conditions: seepage face and unit gradient in terms of soil volumetric water content?" Tags="|hydrology|soil|soil-science|hydrogeology|soil-moisture|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24160" PostTypeId="1" CreationDate="2022-08-13T21:40:20.763" Score="3" ViewCount="47" Body="&lt;p&gt;Recently, I visited the &lt;a href=&quot;https://en.wikipedia.org/wiki/Divide_Creek&quot; rel=&quot;nofollow noreferrer&quot;&gt;Divide Creek birfucation&lt;/a&gt; in Canada where a creek bifurcates with one arm flowing to Pacific and the other to Arctic Ocean and I was wondering how does this rather rare situation plays with the concept of drainage divide.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Drainage_divide&quot; rel=&quot;nofollow noreferrer&quot;&gt;Per Wikipedia&lt;/a&gt;, drainage divide is the boundary between two drainage basins. However, it cannot be practically determined what arm of the bifurcation the water flowing into it will continue. Hence the whole drainage basin of the creek upstream of the bifurcation cannot be said to belong to either the Pacific or the Arctic basins and it forms kind of a gap in the Continental Divide.&lt;/p&gt;&#xA;&lt;p&gt;Drainage divides are often used to trace borders of political, economical, or other importance. Is there any convention for how a divide is traced in such situations?&lt;/p&gt;&#xA;&lt;p&gt;What are all the various ways this has been dealt with? For instance, the Continental Divide and hence Alberta/British Columbia border seem to be traced along the western border of the non-defined area effectively granting it to Alberta.&lt;/p&gt;&#xA;&lt;p&gt;Are there any historical stories where these non-defined parts of drainage divides led to disputes about how the border should be traced?&lt;/p&gt;&#xA;" OwnerUserId="26469" LastEditorUserId="26469" LastEditDate="2022-08-24T00:08:12.473" LastActivityDate="2022-08-24T00:08:12.473" Title="How is drainage divide defined upstream of bifurcation?" Tags="|hydrology|geography|mapping|hydrogeology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24161" PostTypeId="1" CreationDate="2022-08-13T23:50:15.110" Score="4" ViewCount="56" Body="&lt;p&gt;My grade-7 geography textbook contains these world average temperatures for January and July.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JVbw3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JVbw3.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;Average air temperatures in January (winter in the northern hemisphere)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0kpTD.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0kpTD.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;Average air temperatures in July (summer in the northern hemisphere)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In these images, we can see differing behavior in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Bering_Strait&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bering Strait&lt;/a&gt; (between Russia and Alaska): in winter (top), the &lt;a href=&quot;https://www.merriam-webster.com/dictionary/isotherm&quot; rel=&quot;nofollow noreferrer&quot;&gt;isotherm&lt;/a&gt; bulges north of the Bering Strait, while towards the south we see fairly straight isotherms.  However, in summer, the isotherm bulges south of Bering Strait.  I'm guessing this is related to the &lt;a href=&quot;https://oceanservice.noaa.gov/education/tutorial_currents/05conveyor2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Conveyor Belt&lt;/a&gt;, but I'm not sure.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question&lt;/strong&gt;: Why do the isotherms bulge north of the Bering Strait in winter, and bulge south of the Bering Strait in summer?&lt;/p&gt;&#xA;" OwnerUserId="18754" LastEditorUserId="18754" LastEditDate="2022-08-14T03:08:54.777" LastActivityDate="2022-08-14T03:08:54.777" Title="Why do the isotherms bulge north of the Bering Strait in winter, and bulge south of the Bering Strait in summer?" Tags="|climate|temperature|ocean-currents|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24162" PostTypeId="1" AcceptedAnswerId="24182" CreationDate="2022-08-14T10:28:39.540" Score="1" ViewCount="686" Body="&lt;p&gt;I read that most radiation reaching us from the sun is visible light. Yet, heat can only be radiated away from earth as infrared.&lt;/p&gt;&#xA;&lt;p&gt;Is this correct? If so, why can the oceans (say) absorb heat from visible light but only radiate heat away as infrared?&lt;/p&gt;&#xA;&lt;p&gt;(I am excluding reflection for the purpose of this question. The light must be absorbed, warming the molecules to count.)&lt;/p&gt;&#xA;" OwnerUserId="27110" LastEditorUserId="28050" LastEditDate="2022-08-18T18:32:41.997" LastActivityDate="2022-08-18T19:17:02.517" Title="Does visible light warm the earth?" Tags="|climate-change|greenhouse-gases|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24163" PostTypeId="1" CreationDate="2022-08-14T22:35:17.607" Score="6" ViewCount="93" Body="&lt;p&gt;The primordial Lunar crust is mostly calcic plagioclase. However, why did the Lunar Magma Ocean produce so much anorthite, why not a feldspar of a different composition, like albite or orthoclase for instance?&lt;/p&gt;&#xA;" OwnerUserId="27423" LastActivityDate="2022-08-15T20:55:33.657" Title="Why is the Lunar crust anorthite?" Tags="|mineralogy|planetary-science|moon|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24164" PostTypeId="1" CreationDate="2022-08-14T22:46:08.460" Score="4" ViewCount="339" Body="&lt;p&gt;The picture of this cloudy sky was taken today in Hamburg, Germany. Any idea, what it is, where it comes from and if it has a special name?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4uUYy.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4uUYy.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27424" LastEditorUserId="2470" LastEditDate="2022-08-15T00:18:38.563" LastActivityDate="2022-08-15T00:18:38.563" Title="What is the name and effect behind this circular cloud phenomenon?" Tags="|meteorology|clouds|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24165" PostTypeId="2" ParentId="24150" CreationDate="2022-08-15T06:10:55.117" Score="1" Body="&lt;p&gt;Perhaps you would want to point your attention towards crowdsourced data, e.g. data from vehicles, smartphones and private weather stations etc.&#xA;Unless you can get direct access to raw output from a barometer operated by a meteorological institute, crowdsourced data will perhaps be the only network where you can resolve pressure in the timescales you are aiming at.&lt;/p&gt;&#xA;&lt;p&gt;Take a look at figure 1, &lt;a href=&quot;https://rmets.onlinelibrary.wiley.com/doi/pdf/10.1002/met.1805&quot; rel=&quot;nofollow noreferrer&quot;&gt;in this article&lt;/a&gt;, there you can get a rough idea of small-scale fluctuations and synoptic scale changes. You can try getting that data or simply download a barometer app to a few smartphones and analyse the results. Usually, smartphone barometers have relatively high precision (but low accuracy).&#xA;Alternatively, look at the &lt;a href=&quot;https://wow.metoffice.gov.uk/?_gl=1*e7w2rb*_ga*MTYyNTY3Njg0MS4xNjYwNTQzNTg4*_ga_2MWC7FCEB2*MTY2MDU0MzU4Ny4xLjAuMTY2MDU0MzU4Ny4w&quot; rel=&quot;nofollow noreferrer&quot;&gt;WoW Network&lt;/a&gt; hosted by UK Met Office and KNMI, which presents data from private weather stations.&lt;/p&gt;&#xA;" OwnerUserId="17522" LastActivityDate="2022-08-15T06:10:55.117" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24166" PostTypeId="1" CreationDate="2022-08-15T12:08:57.063" Score="1" ViewCount="39" Body="&lt;p&gt;The sun is directly overhead in Barbados twice a year, my guess is approx 5-6th May and 5-6th August. What are the exact dates?&lt;/p&gt;&#xA;" OwnerUserId="27427" LastEditorUserId="27427" LastEditDate="2022-08-15T12:13:16.343" LastActivityDate="2022-08-15T12:13:16.343" Title="Sun overhead in Barbados" Tags="|geography|" AnswerCount="0" CommentCount="3" ClosedDate="2022-08-16T09:45:58.823" ContentLicense="CC BY-SA 4.0" />
  <row Id="24167" PostTypeId="2" ParentId="24156" CreationDate="2022-08-15T14:25:57.920" Score="3" Body="&lt;p&gt;Dew point temperature is the temperature where saturation water vapor pressure &lt;span class=&quot;math-container&quot;&gt;$e_s$&lt;/span&gt; is reached. If we use an empirical formula for the saturation water vapor pressure, like the Magnus formula given by&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;e_s(T_d) = 6.1078 \exp\left({\frac{17.1 \cdot T_d}{235 + T_d}}\right) \text{hPa},&#xA;\end{equation}&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$T_d$&lt;/span&gt; is the dew point temperature (Caution: &lt;span class=&quot;math-container&quot;&gt;$T_d$&lt;/span&gt; needs to be in degrees Celsius and note that &lt;span class=&quot;math-container&quot;&gt;$e_s$&lt;/span&gt; is given in hPa), we can find the water vapor pressure &lt;span class=&quot;math-container&quot;&gt;$e$&lt;/span&gt;. The formula is based on &lt;a href=&quot;https://doi.org/10.1007/3-540-35017-9&quot; rel=&quot;nofollow noreferrer&quot;&gt;this book by Kraus&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Relative humidity is just given by &lt;span class=&quot;math-container&quot;&gt;$RH = e/e_s$&lt;/span&gt;. Now we can calculate the relative based on the following variables:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; [°C] (ambient Temperature)&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$T_d$&lt;/span&gt; [°C] (dew point temperature)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Now set&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;e (T_d) = 6.1078 \exp\left({\frac{17.1 \cdot T_d}{235 + T_d}}\right) \text{hPa}&#xA;\end{equation}&lt;/span&gt;&#xA;and&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;e_s (T) = 6.1078 \exp\left({\frac{17.1 \cdot T}{235 + T}}\right) \text{hPa}.&#xA;\end{equation}&lt;/span&gt;&#xA;Finally calculate &lt;span class=&quot;math-container&quot;&gt;$RH = e/e_s$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Note that the Magnus formula is based on the integrated Clausius-Clapeyron equation. The factor 6.1078 hPa is a reference level water vapor pressure (at 273.15 K, assuming a constant specific heat capacity).&lt;/p&gt;&#xA;&lt;p&gt;One more word of caution. The WMO has given some guidelines on how to calculate certain variables. If I'm not mistaken you can find them &lt;a href=&quot;https://community.wmo.int/activity-areas/imop/wmo-no_8&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; (see p188 of the document which is unfortunately not available anymore without registration).&lt;/p&gt;&#xA;" OwnerUserId="18833" LastEditorUserId="18833" LastEditDate="2022-11-17T14:29:44.570" LastActivityDate="2022-11-17T14:29:44.570" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24168" PostTypeId="1" CreationDate="2022-08-15T18:34:57.357" Score="1" ViewCount="629" Body="&lt;p&gt;For some reason, I can only find the answer in ppm and I don’t know how to do this conversion.&lt;/p&gt;&#xA;" OwnerUserId="26907" LastEditorDisplayName="user27316" LastEditDate="2022-08-16T07:59:53.687" LastActivityDate="2022-08-16T15:16:01.393" Title="What is the current atmospheric concentration of $\small\sf{CO_2}$ in the atmosphere in atm (or bar)?" Tags="|atmosphere|climate|co2|carbon|air|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24169" PostTypeId="1" CreationDate="2022-08-15T19:17:41.690" Score="4" ViewCount="184" Body="&lt;p&gt;Indonesia decided to relocate the capital, in part due to environmental struggles facing Jakarta:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;one of the fastest sinking cities in the world due to the over extraction of groundwater&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.theguardian.com/world/2022/jan/18/indonesia-names-new-capital-nusantara-replacing-sinking-city-of-jakarta&quot; rel=&quot;nofollow noreferrer&quot;&gt;theguardian.com&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VnvQY.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VnvQY.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;Source: &lt;a href=&quot;https://www.trtworld.com/in-depth/rising-tides-and-sinking-cities-161804&quot; rel=&quot;nofollow noreferrer&quot;&gt;trtworld.com&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;If the city is sinking due to the extraction of groundwater, maybe it is possible to reverse &lt;em&gt;(or at least stabilize)&lt;/em&gt; the process by pumping the water back in?&lt;/p&gt;&#xA;" OwnerUserId="14546" LastEditorUserId="6298" LastEditDate="2022-08-18T06:11:43.543" LastActivityDate="2022-08-18T06:11:43.543" Title="Can pumping water into the aquifiers reverse the sinking of cities like Jakarta?" Tags="|geophysics|groundwater|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24170" PostTypeId="2" ParentId="18918" CreationDate="2022-08-15T19:27:34.780" Score="-6" Body="&lt;p&gt;It is my genuine opinion that &lt;strong&gt;YES&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;h3&gt;How much exactly?&lt;/h3&gt;&#xA;&lt;p&gt;See the example: &lt;a href=&quot;https://en.wikipedia.org/wiki/Qattara_Depression_Project&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Qattara_Depression_Project&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Qattara depression is a region that lies 60 m below sea level on average and is currently a vast, uninhabited desert. By connecting the region and the Mediterranean Sea with tunnels and/or canals, water could be let into the area. The inflowing water would then evaporate quickly because of the desert climate. This way a continuous flow of water could be created if inflow and evaporation were balanced out. With this continuously flowing water, hydroelectricity could be generated.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://gis.stackexchange.com/a/267199&quot;&gt;this answer&lt;/a&gt;: &lt;code&gt;3mm&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;(current annual sea rise is around &lt;code&gt;3-4mm&lt;/code&gt; per year)&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/P7I15.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/P7I15.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;According to my math: &lt;code&gt;3mm&lt;/code&gt;&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;Volume of Ocean 1,350,000,000   cubic kilometer&#xA;Volume of Qattara   1213    cubic kilometers&#xA;        &#xA;The ratio   0.0000008985185185  &#xA;Average depth of Ocean  3700    meters&#xA;&#xA;0.0000008985185185 * 3700m = 0.003324518519m&#xA;        &#xA;0.3324518519cm&#xA;3.324518519mm&#xA;&#xA;Evaporation, changing water table, changing weather patterns not included .&#xA;Too many 2nd and 3rd order effects to reliably predict.&#xA;&#xA;Calculation above: pure math based on the volume.&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;h3&gt;Scientific papers about Quattara Depression Project&lt;/h3&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Linked from the Wikipedia notes - &lt;a href=&quot;https://link.springer.com/chapter/10.1007/978-3-642-14779-1_23&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mapping of the Qattara Depression, Egypt, using SRTM Elevation Data for Possible Hydropower and Climate Change Macro-Projects&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The transformation of Qattara Depression into isolated anthropogenic inland sea could provide some ocean level adjustment, as well as generate energy, induce rainfall over some of the adjacent desert, reduce hottest desert daytime and nighttime air temperatures, and permit new local-use fisheries (aquaculture) as well as international tourism resorts.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/L5x8d.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/L5x8d.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://energycentral.com/c/ec/qattara-depression-project-time-revisit&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://energycentral.com/c/ec/qattara-depression-project-time-revisit&lt;/a&gt; - very detailed proposal, including building it in stages, as the water flows into the depression it generates hydropower&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Despite nearly a century of studies and proposals, and despite high interest on the part of Egyptian authorities, all plans for development of the depression have come to naught. In the end, they foundered on the analysis of costs vs. benefits and risks. A lot has changed, though, in the four decades since the last feasibility study was commissioned — and ultimately rejected — by the Egyptian government of Anwar Sadat. Perhaps it’s time to revisit?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;h3&gt;Technical feasibility and roadmap&lt;/h3&gt;&#xA;&lt;p&gt;This can be achieved with the technology that is available Today:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;developed in stages&lt;/li&gt;&#xA;&lt;li&gt;generating hydropower in the process&lt;/li&gt;&#xA;&lt;li&gt;pumping water uphill when excess energy&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;TBD. TBC. This answer can be improved. Old papers didn't account for Elon Musk and Boring Company though when calculating the cost.&lt;/p&gt;&#xA;&lt;h3&gt;Financing&lt;/h3&gt;&#xA;&lt;p&gt;ROI of reducing sea levels might be better than relocating cities that go underwater, however it will require some transnational agreements &lt;em&gt;(country A has a sinking city, country B has a depression, financing coming from X)&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;h3&gt;Availability of labour&lt;/h3&gt;&#xA;&lt;p&gt;There is another large space project - &lt;a href=&quot;https://www.youtube.com/watch?v=ibfEiWDAq28&amp;amp;t=1236s&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Grand Africa Green Up&lt;/a&gt; - they mentioned availability of labour. Useful to know.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/34EPD.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/34EPD.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;h3&gt;Ethical aspect of geoengineering&lt;/h3&gt;&#xA;&lt;p&gt;We are already doing geoengineering with greenhouse gases in the atmosphere ‍♀️ to use some desert and create energy, create jobs, and reduce sea levels - benefits far outweigh any potential concerns.&lt;/p&gt;&#xA;&lt;h3&gt;Note about glaciers and $$$&lt;/h3&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/d41586-018-03036-4&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geoengineer polar glaciers to slow sea-level rise&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;If nothing is done, 0.5–5% of the world’s population will be flooded each year after 2100. For example, a 0.5-metre rise in Guangzhou, China, would displace more than 1 million people; a 2-metre rise would affect more than 2 million1. Without coastal protection, the global cost of damages could reach US$50 trillion a year. Sea walls and flood defences cost tens of billions of dollars a year to construct and maintain.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;h3&gt;Related projects&lt;/h3&gt;&#xA;&lt;p&gt;Not affiliated in any way, just being aware of their existence, in the theme of using desert (not just flooding):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;http://carbon.ycombinator.com/desert-flooding/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://carbon.ycombinator.com/desert-flooding/&lt;/a&gt; - it focuses on farming algae for CO2&lt;/li&gt;&#xA;&lt;li&gt;company that does exactly that: &lt;a href=&quot;https://www.brilliantplanet.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.brilliantplanet.com/&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Desertec&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Desertec&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Medgrid&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Medgrid&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://xlinks.co/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://xlinks.co/&lt;/a&gt; - solar farm on Sahara, cable to the UK&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://suncable.energy/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://suncable.energy/&lt;/a&gt; - solar farm in Australia, cable to Singapore&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;EDIT / UPDATE:&lt;/strong&gt; I've updated this answer a few times to reflect the feedback in the comments - thank you  If you can, if you feel like it - please reverse the downvotes so that this answer receives some attention and bubbles on top - math adds up and people are already actively working on it.&lt;/p&gt;&#xA;" OwnerUserId="14546" LastEditorUserId="14546" LastEditDate="2022-11-06T18:16:14.667" LastActivityDate="2022-11-06T18:16:14.667" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="24171" PostTypeId="2" ParentId="24163" CreationDate="2022-08-15T20:55:33.657" Score="6" Body="&lt;p&gt;A base-level justification is that calcium is much more abundant than sodium or potassium - about 10 times in bulk earth, and double in the crust. Since the moon is thought to have formed as a result of a collision with another Mars-sized object 4.5 billion years ago, the bulk composition of the Moon would have been influenced by the Earth's composition, particularly because the Earth hadn't differentiated very much (i.e., become chemically layered) at the time of the impact.&lt;/p&gt;&#xA;&lt;p&gt;A more important reason involves the process of differentiation itself. The Moon has been geologically dead for about 3 billion years now, meaning that it can't sustain volcanic systems and so its geology is effectively set in stone (ha). When it first formed, the moon would have undergone some differentiation (i.e., heavy elements like Fe and Ni concentrate in the core), leaving essentially a magma ocean of roughly basaltic composition. Calcic plagioclase - anorthite - is a common liquidus mineral (i.e., early to crystallize) in magma of this composition, and it predominates because Ca becomes stable in the solid phase much earlier than either K or Na do (a concept called 'compatibility').&lt;/p&gt;&#xA;&lt;p&gt;The thing about anorthite is it is less dense than your typical basaltic magma (~2.7 g/cm&lt;sup&gt;3&lt;/sup&gt; compared to ~3.3 g/cm&lt;sup&gt;3&lt;/sup&gt; for basalt), and so it floats while the ferromagnesian minerals (olivine, pyroxene) sink! This is why so much of the lunar surface is covered in anorthosite. The other rock on the surface of the moon is basalt, erupted from the residual basaltic magma at depth onto the maria during its active phase 3 billion years ago.&lt;/p&gt;&#xA;" OwnerUserId="27389" LastActivityDate="2022-08-15T20:55:33.657" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24172" PostTypeId="2" ParentId="24168" CreationDate="2022-08-16T01:35:23.163" Score="3" Body="&lt;p&gt;What I think you are asking for is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Partial_pressure&quot; rel=&quot;nofollow noreferrer&quot;&gt;partial pressure&lt;/a&gt; of carbon dioxide in the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;The partial pressure of carbon dioxide can be determined, where,&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$P_{CO_2} \ = \ x_{CO_2}\cdot P_{atm}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;One mole of any substance is equal to exactly 6.022⋅10&lt;sup&gt;23&lt;/sup&gt; molecules of that substance (Avogadro's number, &lt;span class=&quot;math-container&quot;&gt;$N_A$&lt;/span&gt;).&lt;/p&gt;&#xA;&lt;p&gt;The number of moles of carbon dioxide is,&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$Moles\ of\ CO_2 \ = \ Number\ of\ molecules\ of\ CO_2 \cdot N_A$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;If the atmosphere has a carbon dioxide concentration of 400 ppm, then&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$n_{CO_2}\ = \ \frac{400}{1\ 000\ 000} \cdot N_A \ = \ 0.0004 \cdot N_A$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Thus, the partial pressure of carbon dioxide in the atmosphere will be,&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$P_{CO_2} \ = 0.0004 \cdot 101\ 325 \ = \ 40.53 \ Pa \ = 0.0004 \ atm \ = \ 0.304 \ mmHg$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-08-16T01:35:23.163" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24173" PostTypeId="2" ParentId="24169" CreationDate="2022-08-16T08:40:24.440" Score="6" Body="&lt;p&gt;Subsidence in environments like Jakarta has several causes, as described in &lt;a href=&quot;https://d-nb.info/1142926850/34&quot; rel=&quot;noreferrer&quot;&gt;Abidin et al, 2015&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Natural processes of compaction of relatively 'young' alluvial soils&#xA;under their own weight&lt;/li&gt;&#xA;&lt;li&gt;Loading due to construction of buildings,&#xA;roads etc.&lt;/li&gt;&#xA;&lt;li&gt;Groundwater abstraction.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;The first two processes are pretty much irreversible.&lt;/p&gt;&#xA;&lt;p&gt;Pumping water back into the aquifer would slow the rate of subsidence, but even if pore water pressures were completely restored to the natural, pre-pumping, levels  it would be very unlikely to reverse the subsidence. In aquifers such as sandstones where the rock matrix is rigid the aquifer can expand and contract linearly with pore pressures, but the total amount of subsidence is generally low. However in alluvial and deltaic settings where there are layered aquifers and aquitards, reducing pore pressure in the aquitards causes irreversible deformation of the structure of clays and silts. It is this deformation of the aquitards that is responsible for high rates of subsidence, and the resulting compaction is largely irreversible. &lt;a href=&quot;https://pubs.usgs.gov/circ/circ1182/&quot; rel=&quot;noreferrer&quot;&gt;USGS Circular 1182&lt;/a&gt; provides a good overview of process and case studies.&lt;/p&gt;&#xA;&lt;p&gt;Numerous case studies have shown that rebound when levels are restored may be as little as 10% of the subsidence caused by pumping.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2022-08-16T08:40:24.440" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24174" PostTypeId="1" CreationDate="2022-08-16T13:44:28.870" Score="1" ViewCount="75" Body="&lt;p&gt;I am trying to run a catchment model using MIKE-SHE (2020 version, DHI) including an unsaturated zone (UZ) and a saturated zone (SZ) in the set-up. I have specified the ‘Finite Difference’ method for both the overland flow and SZ, and Richards Equation for the UZ. I have entered property data for the UZ and SZ materials (for now the default values for sand were used for the UZ); however, I get the following error, followed by termination:&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;ERROR: UZ column shorter than the initial water depth in ( 7    146)&#xA;Depth to groundwater: 0.90 m&#xA;Length of UZ column: 0.90 m (profile no. 6)&#xA;Termination….&#xA;Calling MIKE 1D with stop request after 0 timesteps…&#xA;Ok&#xA;Abnormal termination&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;It looks like the error is due to a single grid cell (7,146), but I do not know the reason for the error and what I can adjust to resolve it.&lt;/p&gt;&#xA;" OwnerUserId="27288" LastActivityDate="2022-08-17T08:30:48.037" Title="MIKE-SHE model run error: “UZ column shorter than the initial water depth”" Tags="|hydrology|models|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24175" PostTypeId="1" CreationDate="2022-08-16T14:58:50.577" Score="2" ViewCount="367" Body="&lt;p&gt;I am trying to run a coupled MIKE-SHE - MIKE-HydroRiver (MIKE 1D) model (2020 version) on a daily timestep. The model gets through the preprocessing stage without a problem but then shows an error message in the first timestep and stops running. The error is to do with the river water level in the MIKE-Hydro model being extremely high, however there was no rain in the first timestep and the initial water levels input in MIKE-Hydro were not deep. The river cross sections in the MIKE-Hydro model were derived automatically from the DEM that was used in the MIKE-SHE model.  The MIKE-SHE model has an unsaturated zone (UZ) and saturated zone (SZ), the latter set-up to use the ‘Linear Reservoir’ calculation option.  After playing around with increasing the MIKE-Hydro calculation timestep from 10 mins to 5 seconds, and changing the UZ and SZ layers back to global settings, I managed to get the model to run for about 51% after which it crashed, showing a similar error message about river water levels.  The message is as follows:&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;‘ERROR: Water level exceeded maximum on 1 grid point(s). Largest exceedance&#xA;on reach 'Berg', chainage: 15500.00 m. Water depth is 0.4886 m which is more than 4.0000 times the&#xA;cross section height. Water level is 245.44 m. (HD_ERR_WLAboveMaxOnXS)&#xA;Simulation time = 2013-08-27 11:07:30 (time step 6764489).&#xA;Exception: Water level exceeded maximum on 1 grid point(s). Largest&#xA;exceedance on reach 'Berg', chainage: 15500.00 m. Water depth is 0.4886 m which is more than&#xA;4.0000 times the cross section height. Water level is 245.44 m.’&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/866PZ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/866PZ.png&quot; alt=&quot;Screen grab of cross section set-up&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27288" LastActivityDate="2022-09-23T19:09:49.950" Title="MIKE-SHE and MIKE-HydroRiver model run error “Water level exceeded maximum…more the 4.0000 times cross section height”" Tags="|hydrology|models|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24176" PostTypeId="2" ParentId="24168" CreationDate="2022-08-16T15:16:01.393" Score="3" Body="&lt;p&gt;Not nearly so elegant as @fred answer: 400 ppm = 0.04% , then CO 2 is 0,04 % or 0.0004 atm.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2022-08-16T15:16:01.393" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24177" PostTypeId="1" AcceptedAnswerId="24185" CreationDate="2022-08-17T07:27:42.893" Score="9" ViewCount="7468" Body="&lt;p&gt;I came to know that Coriolis effect is maximum at the poles and negligible at the equator. I could not figure a logical meaning behind it. Could someone please explain? Also, does it have anything to do with the trade winds and the ITCZ?&lt;/p&gt;&#xA;" OwnerUserId="27433" LastEditorUserId="2470" LastEditDate="2022-08-17T08:05:48.387" LastActivityDate="2022-08-20T13:22:27.057" Title="Why is the Coriolis effect zero near the equator?" Tags="|meteorology|" AnswerCount="3" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="24179" PostTypeId="1" AcceptedAnswerId="24491" CreationDate="2022-08-17T06:41:00.410" Score="7" ViewCount="461" Body="&lt;p&gt;I'm wondering how much damage the Russian invasion of Ukraine has done to the climate, in particular how many tons of carbon has been released into the atmosphere. I'd be surprised if it isn't substantial, but I don't know exactly how much.&lt;/p&gt;&#xA;&lt;p&gt;Google yields some results - the invasion certainly wasn't good for the climate. However the results I saw generally focus on how the breakdown in diplomatic relations makes it harder to agree on measures. I'm only interested in the direct impact of the war.&lt;/p&gt;&#xA;&lt;p&gt;An analysis of the direct climate impact of this war would be ideal. It doesn't have to be this war as well - some estimate of how much carbon is released in any war will also work.&lt;/p&gt;&#xA;" OwnerUserId="27435" OwnerDisplayName="Allure" LastEditorDisplayName="user27316" LastEditDate="2022-08-18T05:04:15.587" LastActivityDate="2022-11-11T18:20:17.270" Title="How much carbon dioxide does war release?" Tags="|climate-change|carbon-cycle|" AnswerCount="2" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="24180" PostTypeId="2" ParentId="24174" CreationDate="2022-08-17T08:30:48.037" Score="1" Body="&lt;p&gt;It looks like the UZ column in your model does not extend deep enough in this set-up in some locations.&lt;/p&gt;&#xA;&lt;p&gt;In MIKE-SHE, when using the UZ Richard’s equation and SZ Finite Difference coupling, the UZ ‘soil’ profile and the SZ material column in the model need to overlap: have the bottom depth of the UZ profile extend &lt;em&gt;below&lt;/em&gt; the top of the SZ. Also, the groundwater table elevation should always be above the bottom of the UZ profile. Although the water table is simulated in the SZ module, if the water table drops to an elevation that is below the bottom of the model's UZ profile then there is effectively an unsaturated layer that is located &lt;em&gt;below&lt;/em&gt; the UZ calculation domain of the model. This can cause errors in the pressure head calculation at the bottom of the modelled UZ profile.&lt;/p&gt;&#xA;&lt;p&gt;The model error you received shows that the groundwater table was at the very bottom of the UZ profile, rather than lying within the UZ profile, at the specified grid cell (7,146) at the beginning of the simulation.  This may have been true for other cells as well, but the model terminated after the first case was detected.&lt;/p&gt;&#xA;&lt;p&gt;The UZ profiles should be defined to extend &lt;em&gt;below&lt;/em&gt; the deepest depth that the groundwater table will reach in the simulation.&lt;/p&gt;&#xA;&lt;p&gt;It is also suggested that the uppermost &lt;em&gt;calculation layer&lt;/em&gt; of your SZ column should be defined such that the groundwater table will always be located within this top SZ layer.  This is because the model’s exchange of water between the UZ and SZ is calculated for the top SZ layer only.  Because of this, to be safe, the UZ profile could be defined to extend down to a depth that is just below the bottom elevation of this top SZ calculation layer.&lt;/p&gt;&#xA;&lt;p&gt;To fix your problem, try extending your UZ ‘soil’ profile further downwards to cover the full range depths you expect for the water table: adjust both the ‘Soil Profile’ table and calculation cell ‘Vertical Discretization’ table for the relevant soil/material profiles. NB: The MIKE-SHE interface labels this as a ‘Soil Profile’, but it may need to extend beyond what is often defined as ‘soil’, into weathered rock layers that are frequently unsaturated.&lt;/p&gt;&#xA;&lt;p&gt;You may also need to adjust the thickness (or top and bottom elevations) of your top SZ calculation layer so that the water table also lies within that top layer throughout the simulation. Getting these depths right for the full length of the simulation may be an iterative process if the groundwater table is predicted to move up and down by large amounts.&lt;/p&gt;&#xA;" OwnerUserId="27371" LastActivityDate="2022-08-17T08:30:48.037" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24181" PostTypeId="1" CreationDate="2022-08-17T08:54:36.060" Score="2" ViewCount="144" Body="&lt;p&gt;I am trying to run a coupled hydrology-hydraulic, MIKE-SHE - MIKE-HydroRiver (MIKE 1D) model (2020 version, DHI). To get the MIKE 1D hydraulic simulation to run without stability issues I had to use a 5-second timestep. The coupled model seemed to run without a problem until it was about 83% through, had simulated about 5 years worth, when it showed an error message in the log and the programme closed itself.&lt;/p&gt;&#xA;&lt;p&gt;The saved WM log file showed the following:&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Error writing item file: C:\Users\User\Desktop\working\UpMols\Result\UpMols_13032019.she - Result Files\UpMols_13032019_ET_AllCells.dfs2&#xA;msheDFS Error: Unable to write dynamic item&#xA;Error writing datatype, subtype, time: 1, 1, 44184.0000000000&#xA;Termination...&#xA;Calling MIKE 1D with stop request after 31811040 time steps ...&#xA;Ok&#xA;11:27:50 : Stopped after  82.8 % of simulation&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;My hard-drive is almost full after this run, so perhaps it is a drive space issue? If MIKE 1D needs a 5-second timestep, is my only option to find more drive space to get this to run?&lt;/p&gt;&#xA;" OwnerUserId="27371" LastActivityDate="2022-08-17T11:42:44.857" Title="MIKE-SHE and MIKE-HydroRiver model run error: “Unable to write dynamic item” - drive space issues?" Tags="|hydrology|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24182" PostTypeId="2" ParentId="24162" CreationDate="2022-08-17T09:17:05.617" Score="1" Body="&lt;p&gt;Yes, visible light warms the earth.&lt;/p&gt;&#xA;&lt;p&gt;Comprehensive explanations are in this cross-post to Physics Stack Exchange &lt;a href=&quot;https://physics.stackexchange.com/questions/723331/why-do-dark-objects-absorb-visible-light-but-only-emit-infrared-radiation&quot;&gt;Why do dark objects absorb physical light but only emit infrared radiation?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Briefly, when a visible light photon strikes a dark object, an electron will be excited. While the electron could immediately re-emit the photon, the molecular structure is such that it is much more likely for the electron to move into one of many other states and share the energy around other molecules in the material, thus increasing the temperature of the material. As the energy is spread around, when photons are emitted, they are more likely to have low energy (infrared).&lt;/p&gt;&#xA;" OwnerUserId="27110" LastEditorUserId="27110" LastEditDate="2022-08-18T19:17:02.517" LastActivityDate="2022-08-18T19:17:02.517" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24183" PostTypeId="2" ParentId="24175" CreationDate="2022-08-17T09:22:53.013" Score="1" Body="&lt;p&gt;The error comes from the water depth at a channel cross section being simulated as 4 times the height of that cross section. The “cross section height” here is the elevation difference between the outer edges and the deepest point.&lt;/p&gt;&#xA;&lt;p&gt;Something to note from the error message is that the 'water level' isn’t 245.44 m deep, it is 0.4886 m deep. The elevation of the simulated river water surface is 245.44 m above sea level (mamsl). This is not very clear from the phrasing of the error text, but helps to understand when looking at your cross section input to fix the issue.&lt;/p&gt;&#xA;&lt;p&gt;The hydraulic model engine (MIKE-1D) will assume a vertical wall on either side of a cross section when the cross section is totally flooded, up until the water is simulated as being 4 times the cross section height. At this point it flags that there is likely an unreasonable amount of water.&lt;/p&gt;&#xA;&lt;p&gt;You will want to check your cross sections: did they realistically capture the channel depth?  If you automatically generated your cross sections from a DEM, depending on the resolution of that DEM, you will likely need to manually adjust (i.e. deepen) parts of the cross sections to have a reasonable channel thalweg depth versus the flanking terrain (banks, floodplain). Most DEMs don’t adequately capture the incision of river channels, especially in rugged areas and if the DEM is quite coarse.&#xA;Getting this error for a water depth of about 0.4885 m suggests that the topography entered for this cross section (Berg reach, chainage: 15500.00 m) may be almost flat: 0.488 m / 4 = 0.122 m channel height (elevation range)?&lt;/p&gt;&#xA;&lt;p&gt;If deepening your cross sections doesn’t help, or if you think your cross sections are how they should be, also check the longitudinal profile of your cross section thalwegs, or lowest points, moving down the reach. If there is a big bump somewhere water may be pooling upstream of this, contributing to the excessive depth simulated.&lt;/p&gt;&#xA;" OwnerUserId="27371" LastActivityDate="2022-08-17T09:22:53.013" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24184" PostTypeId="2" ParentId="24181" CreationDate="2022-08-17T11:42:44.857" Score="1" Body="&lt;p&gt;From the error message (“Unable to write”) and the fact that the simulation made it so far before this, it is probably a drive space issue.  Do you need the output of every 5-second timestep? If not you can reduce what gets saved so your hard-drive doesn’t fill up. In both MIKE-SHE and MIKE-Hydro you can set-up the simulations to save the results at larger timestep intervals than the process calculation timesteps. Timesteps for saving results need to be multiples of the calculation timesteps.&lt;/p&gt;&#xA;&lt;p&gt;In your MIKE-Hydro set-up (.mhydro file), go to “Results specifications” and under this go to “Standard results”.  Here you can change the “Storing Frequency” to hourly, daily, or any interval you want.&lt;/p&gt;&#xA;&lt;p&gt;In your MIKE-SHE set-up (.she file), under “Storing of results”, you can choose which outputs you want to save and set the timestep for saving. The gridded results files take up a lot of space. I’d suggest not saving these at subdaily timesteps unless you really need that for your application. You’ll likely want the grid items flagged as being necessary for the catchment water balance calculation, but perhaps don’t need all the grids on the list, as the grid files take up a huge amount of storage space.&lt;/p&gt;&#xA;&lt;p&gt;NB: If you set-up saving “Detailed River Time Series” in MIKE-SHE and give this a larger timestep than the MIKE-Hydro timestep, this won’t change what MIKE-Hydro is saving in the background. This will just save another version of the flow or stage output at the timestep you specified and save it with the MIKE-SHE results. To reduce what MIKE-Hydro saves, you need to change that in MIKE-Hydro as mentioned above.&lt;/p&gt;&#xA;" OwnerUserId="27288" LastActivityDate="2022-08-17T11:42:44.857" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24185" PostTypeId="2" ParentId="24177" CreationDate="2022-08-17T13:17:34.433" Score="13" Body="&lt;p&gt;The Coriolis effect typically refers to the horizontal component of the fictitious acceleration that appears in an Earth-centered, Earth-fixed frame of reference (and also in any other Earth-fixed frame of reference such as local east-north-up) due to a horizontal velocity.&lt;/p&gt;&#xA;&lt;p&gt;A more general expression is that the acceleration due to the Coriolis effect is &lt;span class=&quot;math-container&quot;&gt;$\boldsymbol{\mathrm a}_c = -2\boldsymbol\Omega\times\boldsymbol {\mathrm v}$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$\boldsymbol{\mathrm v}$&lt;/span&gt; is the velocity vector with respect to the rotating Earth, &lt;span class=&quot;math-container&quot;&gt;$\boldsymbol\Omega$&lt;/span&gt; is the Earth's angular velocity vector with respect to inertial, and &lt;span class=&quot;math-container&quot;&gt;$\boldsymbol{\mathrm a}_c$&lt;/span&gt; is the resulting Coriolis acceleration.&lt;/p&gt;&#xA;&lt;p&gt;In local east-north-up coordinates, the Earth's angular velocity vector is &lt;span class=&quot;math-container&quot;&gt;$\boldsymbol\Omega = \omega\,(0, \cos\phi, \sin\phi)$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$\phi$&lt;/span&gt; is the geocentric (not geodetic) latitude and &lt;span class=&quot;math-container&quot;&gt;$\omega$&lt;/span&gt; is the Earth's sidereal rotation rate. At the equator, &lt;span class=&quot;math-container&quot;&gt;$\phi=0$&lt;/span&gt;, so &lt;span class=&quot;math-container&quot;&gt;$\boldsymbol\Omega = (0,\omega,0)$&lt;/span&gt; here. The Coriolis acceleration &lt;span class=&quot;math-container&quot;&gt;$-2\boldsymbol\Omega\times\boldsymbol {\mathrm v}$&lt;/span&gt; has zero horizontal components at the equator if the velocity vector is purely horizontal.&lt;/p&gt;&#xA;&lt;p&gt;However, there is a non-zero vertical component to the Coriolis effect. If you drop a ball from the top of a tall vertical tower at the equator the ball will land to the a bit to the east of the base of the tower due to the Coriolis effect. On the other hand, if you shoot a ball straight up at the equator, the ball will land a bit to the west of where you shot it from.&lt;/p&gt;&#xA;&lt;p&gt;You tagged this question &lt;a href=&quot;/questions/tagged/meteorology&quot; class=&quot;post-tag&quot; title=&quot;show questions tagged &amp;#39;meteorology&amp;#39;&quot; rel=&quot;tag&quot;&gt;meteorology&lt;/a&gt;. Winds are mostly horizontal. The horizontal component of the Coriolis effect due to a horizontal wind at the equator is zero.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-08-17T13:17:34.433" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24186" PostTypeId="2" ParentId="24177" CreationDate="2022-08-17T17:33:31.557" Score="11" Body="&lt;p&gt;David's answer is comprehensive, but perhaps a little technical for the level of the question, so I'll try to offer another angle.&lt;/p&gt;&#xA;&lt;p&gt;Coriolis is an apparent force that causes an air parcel to curve to the right in the northern hemisphere and to the left in the SH and can be understood by a conservation of angular momentum. With regards to how Earth's rotation affects the apparent horizontal movement of wind, these figure gives a nice summary:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/k6Nde.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/k6Nde.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;We can see that closer to the poles, an aircraft will appear to have more Earth &amp;quot;move&amp;quot; beneath them while in the air. Another way to visualize the effects of Earth's rotation is imagining a person standing at the equator and at the pole. Equator-person will feel no rotation along their vertical axis with respect to the planet, while pole-person will continuously spin in place with respect to the planet's axis.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WF3DS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WF3DS.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;Because air parcels are in constant motion over a rotating surface, the amount of apparent horizontal deflection is determined by the latitude of the air.&lt;/p&gt;&#xA;&lt;p&gt;A simplified version of north/south Coriolis force operating on horizontal winds is given by:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lUlWw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lUlWw.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where omega (Ω) is the rate of earth's rotation, or angular velocity, (7.292 x 10-5 sec-1), and phi (ϕ) is the latitude of the wind velocity component (V) in question. Because Earth spins counter-clockwise, the apparent deflection of wind is 90° to the right in the northern hemisphere and 90° to the left in the SH.&lt;/p&gt;&#xA;&lt;p&gt;From the equation we can see that if the latitude is zero, then the horizontal north-south deflection contribution of Coriolis is zero. It's important to note that Coriolis has more components than north-south contributions, like in the vertical and east-west, but for the purposes of wrapping your head around the basics this should suffice.&lt;/p&gt;&#xA;" OwnerUserId="27440" LastEditorUserId="27440" LastEditDate="2022-08-20T13:22:27.057" LastActivityDate="2022-08-20T13:22:27.057" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24187" PostTypeId="1" CreationDate="2022-08-18T11:48:57.797" Score="2" ViewCount="40" Body="&lt;p&gt;I am estimating the wetland water balance variables for the comprehensive wetland module.&#xA;For evaporation, it is calculated based on the net rainfall and average wetland storage area for the month. In the WRSM 2000 manual (Bailey and Pitman, 2015 page 136 of 186), alpha, a shape constant, is defined by relating the wetland volume to surface area as follows:&#xA;a = Anom / Snomb&#xA;Is this equation a typo?&lt;/p&gt;&#xA;" OwnerUserId="27363" LastEditorUserId="27363" LastEditDate="2022-08-23T13:00:01.143" LastActivityDate="2024-01-15T14:08:10.993" Title="WRSM-Pitman: Calculating alpha in the wetland surface area equation for estimating wetland evaporation" Tags="|hydrology|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24188" PostTypeId="1" CreationDate="2022-08-18T11:52:09.873" Score="2" ViewCount="32" Body="&lt;p&gt;I’m working with the comprehensive wetland module in WRSM-Pitman (Bailey and Pitman, 2015) and reconstructing the water balance.&#xA;Apart from parameter differences, which proportion of upstream inflows always increases the wetland storage?&lt;/p&gt;&#xA;" OwnerUserId="27363" LastEditorUserId="27363" LastEditDate="2022-08-23T12:33:22.240" LastActivityDate="2023-05-20T16:03:20.437" Title="Distribution of wetland inflows to the wetland storage in WRSM-Pitman" Tags="|hydrology|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24189" PostTypeId="2" ParentId="24177" CreationDate="2022-08-18T17:57:01.977" Score="5" Body="&lt;p&gt;The Coriolis effect is an effect that applies in a rotating frame of reference when one changes one's distance from the axis of rotation. (Going towards the axis of rotation means that a constant linear velocity would result in an increase in angular velocity, causing an apparent force in the direction of rotation, and vice versa for going away from the axis of rotation). At the equator, the axis of rotation of the Earth is parallel to the tangent plane of the Earth, so traveling on the Earth's surface does not change the distance to the axis. Vertical motion does change the distance, so there is a Coriolis effect on falling objects.&lt;/p&gt;&#xA;&lt;p&gt;There are also symmetry arguments showing that the Coriolis effect at the equator is zero. At the equator, there is nothing distinguishing North from South, so the effect of moving in either direction should be the same, so it must be zero. When you get away from the equator, one direction is moving towards the closest pole, and the other is moving away, and that breaks the symmetry. There's also the argument that since the effect is opposite in the two hemispheres, it must go to zero somewhere, and the most obvious place for that is the equator.&lt;/p&gt;&#xA;" OwnerUserId="11501" LastActivityDate="2022-08-18T17:57:01.977" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24190" PostTypeId="1" AcceptedAnswerId="24192" CreationDate="2022-08-18T18:09:29.947" Score="2" ViewCount="104" Body="&lt;p&gt;QAPF diagrams are double ternary diagrams used for magmatic rock classification based on mineralogy.&lt;/p&gt;&#xA;&lt;p&gt;Quartz and Feldspathoids are opposed on the pointy ends of the diamond, with Alkali feldspar and Plagioclase (feldspar) on the intermediary vertex. That direction indicates from more to less silicate (SiO2) content, leading to formation of one or the other.&lt;/p&gt;&#xA;&lt;p&gt;The other direction differentiates feldspar types, from Alkali feldspar (Na-K) and Plagioclase (Na-Ca). My problem lies here: Albite (Sodium mineral) is the end of the ranges of BOTH of them, thus I don't know which side it should be considered.&lt;/p&gt;&#xA;&lt;p&gt;I made some searches on the web but cannot find anything conclusive as some geologists claim one or the other, while most simply don't talk about it. Does anybody have any answer, if possible with reliable sources?&lt;/p&gt;&#xA;" OwnerUserId="27445" LastEditorUserId="27445" LastEditDate="2022-08-20T20:05:30.657" LastActivityDate="2022-08-20T20:05:30.657" Title="On QAPF (Steckeisen) diagrams, should Albite be considered on the Alkali feldspar or Plagioclase side? Or in-between?" Tags="|geology|mineralogy|rocks|minerals|petrology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24191" PostTypeId="2" ParentId="24162" CreationDate="2022-08-18T18:31:42.583" Score="1" Body="&lt;p&gt;&lt;strong&gt;The short answer is Yes, visible light does warm the earth.&lt;/strong&gt; Then, the earth's surface &lt;em&gt;mostly&lt;/em&gt; emits infrared radiation at normal temperatures. You got &lt;a href=&quot;https://physics.stackexchange.com/a/723420/113377&quot;&gt;a nice answer&lt;/a&gt; about this aspect on the other thread.&lt;/p&gt;&#xA;&lt;p&gt;It's not correct that &amp;quot;most radiation reaching us from the sun is visible light&amp;quot;. For example, &lt;a href=&quot;https://ehs.lbl.gov/resource/documents/radiation-protection/non-ionizing-radiation/light-and-infrared-radiation/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this resource from Lawrence Berkeley National Laboratory&lt;/a&gt; has this statistic:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;It is estimated that more than half (54%) of the sun’s radiation is infrared, whereas 39% is the visible rays and the remaining 7% is the ultraviolet rays.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This seems reasonable, given the spectrum here from &lt;a href=&quot;https://en.wikipedia.org/wiki/Sunlight&quot; rel=&quot;nofollow noreferrer&quot;&gt;the Sunlight article&lt;/a&gt; on Wikipedia. It's partly just the bandwidth of IR radiation compared to visible light:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/64DfR.png&quot; alt=&quot;CC BY-SA Robert A Rohde&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;To get back to your question, Earth's albedo (the amount of radiation reflected from the surface back into space) is about 0.3 on average, but it varies locally and depends on the wavelength of the radiation, per &lt;a href=&quot;https://www.researchgate.net/figure/Spectral-and-effective-dashed-lines-albedo-of-several-widely-used-surfaces-The-ideal_fig1_320295066&quot; rel=&quot;nofollow noreferrer&quot;&gt;this figure&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://i.stack.imgur.com/VzI9I.png&quot; alt=&quot;The wavelength dependence of albedo&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;The 70% of radiation that is absorbed raises the temperature of the material (in general, absorbing radiation of any wavelength will). As the physicists explained, most radiation from bodies at about 20 deg Celsius is in the infrared band.&lt;/p&gt;&#xA;&lt;p&gt;I hope I understood what you were asking. Be careful with sentences like this:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;why can the oceans [...] only radiate heat away as infrared?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This begs the question, because to emit infrared radiation is to &amp;quot;radiate heat&amp;quot;: it's the same thing. In other words, you can't radiate heat away in any other electromagnetic band.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastActivityDate="2022-08-18T18:31:42.583" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24192" PostTypeId="2" ParentId="24190" CreationDate="2022-08-18T19:41:18.547" Score="4" Body="&lt;p&gt;When it comes to igneous rocks classification, the bible is &lt;a href=&quot;https://doi.org/10.1017/CBO9780511535581&quot; rel=&quot;nofollow noreferrer&quot;&gt;Igneous Rocks: A Classification and Glossary of Terms&lt;/a&gt; (Le Maitre et al., 2002). It says (p.4):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A = alkali feldspar, including orthoclase, microcline, perthite,&#xA;anorthoclase, sanidine, and albitic plagioclase (An&lt;span class=&quot;math-container&quot;&gt;$_0$&lt;/span&gt; to An&lt;span class=&quot;math-container&quot;&gt;$_5$&lt;/span&gt;)&lt;/p&gt;&#xA;&lt;p&gt;P = plagioclase (An&lt;span class=&quot;math-container&quot;&gt;$_5$&lt;/span&gt; to An&lt;span class=&quot;math-container&quot;&gt;$_{100}$&lt;/span&gt;) and scapolite&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So I guess everyone is partially right: if your albite is An&lt;span class=&quot;math-container&quot;&gt;$_{0-5}$&lt;/span&gt;, then you should consider it on the A side; if your albite is An&lt;span class=&quot;math-container&quot;&gt;$_{5-10}$&lt;/span&gt;, then you should consider it on the P side.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2022-08-18T20:04:42.873" LastActivityDate="2022-08-18T20:04:42.873" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24194" PostTypeId="1" AcceptedAnswerId="24196" CreationDate="2022-08-19T14:21:08.243" Score="3" ViewCount="57" Body="&lt;p&gt;I am reading a book that in a paragraph talks about the agricultural methods used in prehistoric Finland.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The further north and east, the more extensive the amount of&#xA;burn-beat cultivation, which was a far from primitive form of&#xA;agriculture. The yield was many times higher (twenty- to thirty-fold)&#xA;than on permanent fields (five- to ten-fold), and there were multiple&#xA;varieties of the technique&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;A history of Finland by Henrik Meinander.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;One of them is burn-beating. Like I understand, in burn-beating people cut down the trees in the forests and burn the topsoil. This way they can use that soil for 3 to 6 years for cultivation.&lt;/p&gt;&#xA;&lt;p&gt;The other method is permanent field. I have searched the internet and the result I got was &amp;quot;permanent crops&amp;quot;, &lt;a href=&quot;https://www.farmfundr.com/blog/what-are-permanent-crops&quot; rel=&quot;nofollow noreferrer&quot;&gt;like here&lt;/a&gt;. In which case people planted trees once in a field and harvested them multiple times.&lt;/p&gt;&#xA;&lt;p&gt;But in another research about prehistoric Finland it was saying:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The site of Orijärvi shows that permanent field cultivation, with&#xA;hulled barley as the main crop was conducted from approximately cal AD 600 onwards.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.researchgate.net/publication/337706536_Prehistoric_cultivation_and_plant_gathering_in_Finland_An_archaeobotanical_study&quot; rel=&quot;nofollow noreferrer&quot;&gt;research link&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I see that &amp;quot;permanent field cultivation&amp;quot; is different from &amp;quot;permanent crops&amp;quot;. Because as far as I know you can not harvest a field multiple times in which barley is sown. You must sow barley again to harvest.&lt;/p&gt;&#xA;&lt;p&gt;So what does permanent field mean if prehistoric Finns were sowing barley, oat and etc?&lt;/p&gt;&#xA;" OwnerUserId="27454" LastEditorUserId="27454" LastEditDate="2022-08-20T14:13:12.543" LastActivityDate="2022-08-20T21:27:28.357" Title="What does &quot;permanent field&quot; mean in agriculture?" Tags="|agriculture|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24195" PostTypeId="1" CreationDate="2022-08-19T21:37:49.543" Score="1" ViewCount="321" Body="&lt;p&gt;I want to calculate the Madden-Julian Oscillation (MJO) phase by myself using Real-time Multivariate MJO series 1 (RMM1) and 2 (RMM2) from a data file.&lt;/p&gt;&#xA;&lt;p&gt;The formula for doing so is:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$MJO phase = \arctan\left(\frac{RMM2}{RMM1}\right)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;but that doesn’t get me to an MJO phase of 1 to 8.&lt;/p&gt;&#xA;&lt;p&gt;I’ve trawled the web extensively but can’t find a solution.&lt;/p&gt;&#xA;&lt;p&gt;Thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="27458" LastEditorUserId="18081" LastEditDate="2022-09-09T07:32:47.337" LastActivityDate="2022-09-09T07:32:47.337" Title="How do I calculate the Madden-Julian Oscillation (MJO) phase from RMM1 &amp; RMM2?" Tags="|meteorology|climate|" AnswerCount="0" CommentCount="3" ClosedDate="2022-08-29T22:57:03.990" ContentLicense="CC BY-SA 4.0" />
  <row Id="24196" PostTypeId="2" ParentId="24194" CreationDate="2022-08-20T02:23:00.830" Score="3" Body="&lt;p&gt;I am not familiar with the term burn-beating, but from the description provided by Arvo M. Soininen, &amp;quot;Burn-beating as the technical basis of colonisation in Finland in the 16th and 17th centuries&amp;quot;, &lt;em&gt;Scandinavian Economic History Review&lt;/em&gt;, Vol. 7, No. 2, pp. 150-166 (&lt;a href=&quot;https://www.tandfonline.com/doi/pdf/10.1080%2F03585522.1959.10411414&quot; rel=&quot;nofollow noreferrer&quot;&gt;scan online&lt;/a&gt;) the term appears to refer to &lt;a href=&quot;https://en.wikipedia.org/wiki/Slash-and-burn&quot; rel=&quot;nofollow noreferrer&quot;&gt;slash-and-burn&lt;/a&gt; agriculture.&lt;/p&gt;&#xA;&lt;p&gt;In slash-and-burn agriculture, (most of) the vegetation of an area is cut down and burned, with the resulting plant ash serving as fertilizer due to its mineral content, in particular potassium and phosphorus. Over the course of three to five years, the mineral content of the soil is depleted by successive crops, the field is abandoned, and cultivation moves to the next area. Fields created by slash-and-burn agriculture are therefore of a &lt;em&gt;temporary&lt;/em&gt; nature. Soininen's paper describes multiple different methods of slash-and-burn agriculture practiced in Finland until quite recently.&lt;/p&gt;&#xA;&lt;p&gt;In contrast, fields that, once created, are used for a long and indefinite period of time are &lt;em&gt;permanent&lt;/em&gt; fields. Historically, such fields have been used continuously over time spans ranging from several decades to thousands of years. The abandonment of fields does occasionally occur due to any number of factors that make continued farming difficult, such as marginal soil or climate conditions or lack of manpower. Permanent fields require careful management of the soil to maintain its fertility. Historically this has involved &lt;a href=&quot;https://en.wikipedia.org/wiki/Crop_rotation&quot; rel=&quot;nofollow noreferrer&quot;&gt;crop rotation&lt;/a&gt; and fallowing (in which fields are allowed to &amp;quot;rest&amp;quot; for one or several years), irrigation, and fertilization by animal dung and / or vegetation matter taken from other areas (e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Plaggen_soil&quot; rel=&quot;nofollow noreferrer&quot;&gt;plaggen soil&lt;/a&gt; in parts of Northern Germany, or the use of seaweed in parts of Ireland).&lt;/p&gt;&#xA;&lt;p&gt;The primary cereals for making bread are wheat and rye, while barley and oats may be mixed in. Historically significant portions of the rural population of Europe were sustained by cereal-based food in the form of &lt;a href=&quot;https://en.wikipedia.org/wiki/Gruel&quot; rel=&quot;nofollow noreferrer&quot;&gt;gruel&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Porridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;porridge&lt;/a&gt; rather than by bread, especially prior to the introduction of the potato. Barley can be consumed in the form of &lt;a href=&quot;https://en.wikipedia.org/wiki/Pearl_barley&quot; rel=&quot;nofollow noreferrer&quot;&gt;pearl barley&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Groat_(grain)&quot; rel=&quot;nofollow noreferrer&quot;&gt;groats&lt;/a&gt; and oats in the form of &lt;a href=&quot;https://en.wikipedia.org/wiki/Oatmeal&quot; rel=&quot;nofollow noreferrer&quot;&gt;oatmeal&lt;/a&gt;. Especially in cool and humid climates not very suitable for cultivating wheat and rye, oats were once commonly cultivated and consumed. When &lt;a href=&quot;https://en.wikipedia.org/wiki/Samuel_Johnson&quot; rel=&quot;nofollow noreferrer&quot;&gt;Samuel Johnson&lt;/a&gt; wrote his &lt;a href=&quot;https://en.wikipedia.org/wiki/A_Dictionary_of_the_English_Language&quot; rel=&quot;nofollow noreferrer&quot;&gt;dictionary&lt;/a&gt;, he famously defined oats as: &amp;quot;A grain which in England is generally given to horses, but in Scotland supports the people.&amp;quot; A major historical and modern use of barley has been as malted barley, the main ingredient in beer brewing.&lt;/p&gt;&#xA;&lt;p&gt;In the case of Finland it is interesting to note how late the transition from slash-and-burn agriculture to the use of permanent fields occurred. According to Teija Alenius, &lt;em&gt;Environmental change and anthropogenic impact on lake sediments during the Holocene in the Finnish − Karelian inland area&lt;/em&gt;, Ph.D. thesis, University of Helsinki, 2007 (&lt;a href=&quot;https://helda.helsinki.fi/handle/10138/21221&quot; rel=&quot;nofollow noreferrer&quot;&gt;online&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Another study question concerns the relationship between slash-and-burn cultivation and permanent field cultivation. According to historical records, slash-and-burn cultivation remained the major method of cereal-crop cultivation in eastern Finland until the late 19&lt;sup&gt;th&lt;/sup&gt; century (Soininen 1974). Permanent Iron Age fields, found at the city of Mikkeli, suggest cultivation on permanent fields from the 7&lt;sup&gt;th&lt;/sup&gt; century (Mikkola 2004). This finding is significant, because it is the easternmost permanent prehistoric field complex found in Finland and therefore has a great socio-economic value (Mikkola 2004; Mikkola and Talvio 2000).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="5255" LastEditorUserId="5255" LastEditDate="2022-08-20T21:27:28.357" LastActivityDate="2022-08-20T21:27:28.357" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24197" PostTypeId="1" CreationDate="2022-08-20T09:59:20.080" Score="1" ViewCount="67" Body="&lt;p&gt;There is proverb that sounds like:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Red sun at night, sailor’s delight; red sun in the morning, sailor&#xA;take warning.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Is it valid and if it is then what is it about?&lt;/p&gt;&#xA;" OwnerUserId="21286" LastEditorUserId="6298" LastEditDate="2022-08-20T12:14:34.857" LastActivityDate="2022-08-20T12:14:34.857" Title="What does &quot;red sun at night, sailor's delight&quot; mean and is it true?" Tags="|meteorology|atmosphere|weather-forecasting|sun|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24198" PostTypeId="1" CreationDate="2022-08-20T15:38:32.550" Score="2" ViewCount="26" Body="&lt;p&gt;A lunar apatite sample has a relatively low OH content of 5 ppm, but a an elevated D of 11,000‰ (vs. SMOW). Assuming that water had an original figure of around -100‰ or so, how do I estimate the amount of water present before degassing?&lt;/p&gt;&#xA;" OwnerUserId="27304" LastEditorUserId="26841" LastEditDate="2022-08-23T15:06:15.040" LastActivityDate="2022-08-23T15:06:15.040" Title="Calculate original volatile content of a degassed mineral" Tags="|geochemistry|planetary-science|moon|isotopic|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24199" PostTypeId="1" CreationDate="2022-08-20T17:22:43.383" Score="10" ViewCount="4020" Body="&lt;p&gt;There are areas of land that are in fact, below sea level. Are there any hills or mountains that have bases that start in these below-sea-level areas of land?&lt;/p&gt;&#xA;" OwnerUserId="24504" LastEditorUserId="28050" LastEditDate="2022-09-12T12:14:07.857" LastActivityDate="2022-09-12T12:21:21.543" Title="Are there any (land) hills/mountains with bases below sea level?" Tags="|sea-level|mountains|topography|" AnswerCount="9" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24200" PostTypeId="2" ParentId="24199" CreationDate="2022-08-20T17:48:16.433" Score="-1" Body="&lt;p&gt;This is in part a philosophical question but one that connects to the composition of continental and oceanic crust. If we consider hills and mountains we need to consider to what we are referencing as the &amp;quot;zero&amp;quot; level. Traditinally this has been sea level so any elevation is considered in terms of &amp;quot;meters above mean sea level&amp;quot; (m a.s.l.). With ongoing climate change sea, levels are rising so the elevations are essentially decrasing we need to reference some reference level if qwe need to express elevations. I think it is still an open question as to what this datum will be. In the geological past sea levels have changed depending on a number of factors such as the rate of renewal of new oceanic plate (being relatively low density due to its inherent heat), the volume of land locked ice sheets (lowering the sea level and volume) and other factors.&lt;/p&gt;&#xA;&lt;p&gt;The question can only be answered given the conditions under which the areas considered have been formed, i.e. the formation of new warm and therefore light crust and the volume of land-locked ice under a given climate scenario. The current distribution of elevation above and below sea level is not necessarily in synch with our current climate and certainly current climate change. Therefore there is much to consider when interpreting current topography in terms of current climate and certainly current climate change.&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2022-08-20T17:48:16.433" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24201" PostTypeId="2" ParentId="24199" CreationDate="2022-08-20T20:02:08.720" Score="8" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Mauna_Kea&quot; rel=&quot;noreferrer&quot;&gt;Mauna Kea&lt;/a&gt; is a good example of this. It is generally considered as the tallest mountain on Earth. Even if its elevation is only 4205 meters above sea level, if you add the 6000 meters of its below sea level base, it reaches more than 10 km! From &lt;a href=&quot;https://www.usgs.gov/faqs/how-big-are-hawaiian-volcanoes&quot; rel=&quot;noreferrer&quot;&gt;USGS &amp;quot;How big are the Hawaiian volcanoes?&lt;/a&gt;&amp;quot;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Mauna Kea Volcano rises 13,796 feet (4,205 meters) above sea level but&#xA;extends about 19,700 feet (6,000 meters) below sea level to meet the&#xA;deep ocean floor. Its total height is nearly 33,500 feet (10,211&#xA;meters), considerably higher than the height of the tallest mountain&#xA;on land, Mount Everest (Chomolungma in Tibetan) in the Himalayas,&#xA;which is 29,029 feet (8,848 meters) above sea level.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Basically, any volcano built on an oceanic island (e.g., Piton de la Fournaise at La Réunion, Karthala at Grande Comore...) had its roots below sea level.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2022-08-20T20:02:08.720" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24202" PostTypeId="1" CreationDate="2022-08-20T22:53:31.553" Score="2" ViewCount="241" Body="&lt;p&gt;Here are three definitions of &amp;quot;topographic isolation&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Topographic_isolation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The topographic isolation of a summit is the minimum distance to a point of equal elevation, representing a radius of dominance in which the peak is the highest point.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.wikidata.org/wiki/Property:P2659&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikidata.org&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;minimum distance to a point of higher elevation&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://wiki.gis.com/wiki/index.php/Topographic_isolation&quot; rel=&quot;nofollow noreferrer&quot;&gt;gis.com&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The topographic isolation of a summit is the minimum horizontal (great circle) distance to the nearest point of higher elevation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;http://wiki.gis.com/wiki/index.php/Topographic_isolation&quot; rel=&quot;nofollow noreferrer&quot;&gt;gis.com&lt;/a&gt; site has a table of &amp;quot;The 25 Most Topographically Isolated Mountain Peaks on Earth&amp;quot;. At the top of this table is Mount Everest with an isolation of 40, 008 km. I looked up that 40, 008 km is about the circumference of the Earth.&lt;/p&gt;&#xA;&lt;p&gt;But I am not sure this choice agrees with either of the definitions above because one of the criterion of the definition is not satisfied: there is no other point with equal (or higher) elevation for Everest (or at least the highest point of it anyway).&lt;/p&gt;&#xA;&lt;p&gt;Then again, I did grab rather informal definitions from some wiki pages, so perhaps there are other definitions for more technical work that resolve this apparent contradiction.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Miscellaneous afterthought: we should grant that we are talking about distances on a surface between peaks. There are taller mountains than Everest (e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Olympus_Mons&quot; rel=&quot;nofollow noreferrer&quot;&gt;Olympus Mons&lt;/a&gt;, but we are not considering the time-varying distance between planets in this question.&lt;/p&gt;&#xA;" OwnerUserId="27463" LastActivityDate="2023-01-19T02:55:33.617" Title="Does Everest have a topographic isolation?" Tags="|mountains|topography|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24203" PostTypeId="2" ParentId="24199" CreationDate="2022-08-21T14:11:12.543" Score="17" Body="&lt;p&gt;It's difficult, because to truly have a base below sea level the hill or mountain needs to be surrounded by locations below sea level on all sides.  There aren't many spots on Earth's surface away from oceans below sea level at all... and many of those tend to fill with water as well.  And the larger the terrain rise of the hill/mountain, generally the larger the footprint of the base, so harder and harder to get it entirely below sea level.&lt;/p&gt;&#xA;&lt;p&gt;But &lt;a href=&quot;https://en-us.topographic-map.com&quot; rel=&quot;noreferrer&quot;&gt;topographic-map.com&lt;/a&gt; is one of my favorite sites for exploring topography, and its color scale works out helpful at finding areas below sea level.  And its flexibility lets you root around those areas further... places like California, Egypt, Algeria, Kazakhstan, and the Caspian Sea region.&lt;/p&gt;&#xA;&lt;p&gt;And doing so, I came across this hill in the region of ancient Israel/the modern borders of Palestine &lt;a href=&quot;https://en-ca.topographic-map.com/maps/b6me/Megilot-Yam-HaMelakh-Regional-Council/&quot; rel=&quot;noreferrer&quot;&gt;near the An-Nabi Musa area a bit northwest of the Dead Sea&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FOTpUm.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FOTpUm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bHBd9.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bHBd9.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Looking at the scale and clicking around the &amp;quot;peak&amp;quot;, the bases appear to be around -20 meters on all sides, and the peak elevation 74 meters, so it's just a modest 300 foot hill.  But it looks to fit your request.&lt;/p&gt;&#xA;&lt;p&gt;Google Maps also has topography lines for &lt;a href=&quot;https://www.google.com/maps/search/an-nabi+musa/@31.7656022,35.4337296,14z/data=!5m1!1e4&quot; rel=&quot;noreferrer&quot;&gt;the location&lt;/a&gt; as well... which seems to roughly confirm the existence of this hill and the one further northwest, and that their bases are basically below sea level.  The Layers and Street View of Google also allow you to look further at the area... there's a &lt;a href=&quot;https://www.google.com/maps/@31.7592926,35.4455605,3a,75y,188.72h,103.07t/data=!3m8!1e1!3m6!1sAF1QipOB9-gO1hIjXZoyVPR3a7BBKlCLueZ9o8Ptbf4Z!2e10!3e11!6shttps:%2F%2Flh5.googleusercontent.com%2Fp%2FAF1QipOB9-gO1hIjXZoyVPR3a7BBKlCLueZ9o8Ptbf4Z%3Dw203-h100-k-no-pi-1.2304688-ya96-ro-0-fo100!7i12288!8i3892!5m1!1e4&quot; rel=&quot;noreferrer&quot;&gt;picture&lt;/a&gt; taken near one of the hills.&lt;/p&gt;&#xA;&lt;p&gt;Such hills are oddities because of the incredibly small area of the world to be below sea level (and not covered by water).  But there's nothing else at all to discourage such numerical novelties.  And such areas see so little rain and are entirely disconnected from the ocean that they truly know nothing of what the rest of the world's sea level even means.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-08-21T15:48:25.473" LastActivityDate="2022-08-21T15:48:25.473" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24204" PostTypeId="2" ParentId="24202" CreationDate="2022-08-21T17:29:29.257" Score="0" Body="&lt;p&gt;There is a contradiction, but you have choices in deciding how to resolve it. Here are two:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Everest doesn't have a topographic isolation; call it undefined. It can be as simple as that, but maybe ignores our intuition that Everest is the most isolated.&lt;/li&gt;&#xA;&lt;li&gt;Find a more general definition that preserves the topographic isolations as they are already calculated. One approach to doing this is to calculate topographic isolation as normal for any peak that isn't the highest peak in the set. Then for the highest peak in the set take its topographical isolation to be the greatest distance from itself to anywhere in the space. On a sphere speckled with mountains, this will be the circumference of the sphere (i.e. a great circle's length).&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;While not immediately useful to the original question, this notion of topographic isolation can be readily generalized to many mathematical surfaces embedded in finite dimension and equipped with a suitable metric. For surfaces over an infinite support, the &amp;quot;topographic&amp;quot; isolation of a global maximum may be unbounded (or informally, &amp;quot;infinite&amp;quot;).&lt;/p&gt;&#xA;" OwnerUserId="27463" LastEditorUserId="27463" LastEditDate="2022-08-21T17:35:34.867" LastActivityDate="2022-08-21T17:35:34.867" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24205" PostTypeId="1" CreationDate="2022-08-21T17:59:48.690" Score="6" ViewCount="674" Body="&lt;p&gt;Looking at the tidal calendar for the German North Sea, I wonder why the interval between times is so irregular. Internet searches lead to pages that say the tides should be regular &lt;a href=&quot;https://oceanservice.noaa.gov/education/tutorial_tides/tides05_lunarday.html#:%7E:text=Therefore%2C%20it%20takes%20the%20Earth,24%20hours%20and%2050%20minutes.&quot; rel=&quot;nofollow noreferrer&quot;&gt;24 hours 50 minutes&lt;/a&gt; cycles, but when looking at each column, the changes vary between 16 and 86 minutes. Why is that?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZnQIi.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZnQIi.jpg&quot; alt=&quot;Tidal Calendar&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27467" LastEditorUserId="6298" LastEditDate="2022-08-22T21:28:04.533" LastActivityDate="2022-08-22T21:28:04.533" Title="Why is the time interval between tides so irregular?" Tags="|oceanography|tides|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24206" PostTypeId="2" ParentId="24199" CreationDate="2022-08-21T22:40:18.443" Score="5" Body="&lt;p&gt;Following @JeopardyTempest's advice of rooting around in the Caspian Sea region, a notable feature is &lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Arlan&quot; rel=&quot;noreferrer&quot;&gt;Mount Arlan 1,880m&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As a free-standing peak in the Caspian basin, it's a proper &lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Arlan&quot; rel=&quot;noreferrer&quot;&gt;ultra-prominent&lt;/a&gt; mountain indeed.&#xA;While arguments could go either way on whether the nearby Caspian Sea and Garabogazköl are &amp;quot;properly&amp;quot; the base of the mountain, it's col is sadly slightly above sea level.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SaCzW.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SaCzW.png&quot; alt=&quot;Mount Arlan&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5333" LastActivityDate="2022-08-21T22:40:18.443" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24207" PostTypeId="2" ParentId="24205" CreationDate="2022-08-22T08:06:15.160" Score="3" Body="&lt;p&gt;Whenever one comes across a website that still uses the archaic notion of two tidal bulges, one should go to a different website. &lt;a href=&quot;https://physics.stackexchange.com/a/121858/52112&quot;&gt;There is no tidal bulge&lt;/a&gt;. Quoting from the linked answer at the physics StackExchange,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This was one of Newton's few mistakes. Newton did get the tidal forcing function correct, but the response to that forcing in the oceans: completely wrong.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Newton's equilibrium theory of the tides with its two tidal bulges is falsified by observation. If this hypothesis was correct, high tide would occur when the Moon is at zenith and at nadir. Most places on the Earth's oceans do have a high tide every 12.421 hours, but whether those high tides occur at zenith and nadir is sheer luck. In most places, there's a predictable offset from the Moon's zenith/nadir and the time of high tide, and that offset is not zero.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;One of the most confounding places with regard to the tides is Newton's back yard. If Newton's equilibrium theory was correct, high tide would occur at more or less the same time across the North Sea. That is not what is observed. At any time of day, one can always find a place in the North Sea that is experiencing high tide, and another that is simultaneously experiencing low tide.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The mathematical tools needed to properly analyze the tides were not available in Newton's time. It was Laplace rather than Newton who properly explained the tides. Even Laplace didn't quite get it right. The harmonic analysis tools needed to properly model the tides arose about a century after Laplace, two centuries after Newton.&lt;/p&gt;&#xA;&lt;p&gt;The tides at any one place result from multiple frequency components. Both the Moon and the Sun contribute to tides, with the Moon typically dominating over the Sun, roughly by a factor of two. Two of the many (over 30!) frequency components are&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;M&lt;sub&gt;2&lt;/sub&gt;, the principal lunar semidiurnal component. This component of the tides typically is the dominant frequency with a period of 12.4206012 hours.&lt;/li&gt;&#xA;&lt;li&gt;S&lt;sub&gt;2&lt;/sub&gt;, the principal solar semidiurnal component. This component of the tides typically has a bit less than half of the amplitude of the M&lt;sub&gt;2&lt;/sub&gt; component and has a period of 12 hours.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;When one adds multiple sinusoids (keep in mind that most places use over 30 frequency components to model the tides), the result is a complex shape with peaks that don't exactly match the 12.4206012 hours between the peaks suggested by using the M&lt;sub&gt;2&lt;/sub&gt; component only.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-08-22T08:06:15.160" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24208" PostTypeId="2" ParentId="24199" CreationDate="2022-08-22T08:51:47.427" Score="5" Body="&lt;p&gt;In The Netherlands, after the construction of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Noordoostpolder&quot; rel=&quot;nofollow noreferrer&quot;&gt;Noordoostpolder&lt;/a&gt;, the former islands of &lt;a href=&quot;https://en.wikipedia.org/wiki/Schokland&quot; rel=&quot;nofollow noreferrer&quot;&gt;Schokland&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Urk&quot; rel=&quot;nofollow noreferrer&quot;&gt;Urk&lt;/a&gt; became hills with bases below sea level, although Urk is only partially surrounded by land, Schokland is entirely.  Whereas the surrounding polder has an elevation of between -2.7 and -4.1 metre, the summit of the hill reaches as high as +0.7 metre according to the official topographic map (don't forget your high altitude gear), but it is &lt;a href=&quot;https://www.interessantetijden.nl/2017/08/10/schokland/&quot; rel=&quot;nofollow noreferrer&quot;&gt;apparently sinking and now only 0.0 metre above sea level&lt;/a&gt;.  The former island is a UNESCO World Heritage Site and the primary (the only?) tourist attraction in the region (although there reportedly exists a nettle theme park somewhere in the region).&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/3/32/Schokland_luchtfoto.jpg/1024px-Schokland_luchtfoto.jpg&quot; alt=&quot;Schokland aerial photo&quot; title=&quot;Schokland&quot; /&gt;&lt;br /&gt;&#xA;Schokland seen from above.  &lt;em&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Schokland_luchtfoto.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikimedia Commons&lt;/a&gt;&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;There are also many &lt;a href=&quot;https://en.wikipedia.org/wiki/Terp&quot; rel=&quot;nofollow noreferrer&quot;&gt;terpen&lt;/a&gt; that are above sea level whereas their base is below sea level, but unlike Schokland and Urk, those are artificial hills, and if they count, the list of eligible hills in The Netherlands (in particular in Holland) becomes quite long.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/a/ad/Schokland-natuur-OpenTopo.jpg&quot; alt=&quot;Schokland topographic map&quot; title=&quot;topographic map&quot; /&gt;&lt;br /&gt;&#xA;Schokland topographic map.  &lt;em&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Schokland-natuur-OpenTopo.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikimedia Commons&lt;/a&gt; / Topografische Dienst Kadaster&lt;/em&gt;.  Heights in metre above the &lt;a href=&quot;https://en.wikipedia.org/wiki/Amsterdam_Ordnance_Datum&quot; rel=&quot;nofollow noreferrer&quot;&gt;Amsterdam Ordnance Datum&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2022-08-23T19:34:10.443" LastActivityDate="2022-08-23T19:34:10.443" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24209" PostTypeId="1" AcceptedAnswerId="24241" CreationDate="2022-08-22T09:50:45.413" Score="5" ViewCount="108" Body="&lt;p&gt;I would love to know what exactly we can do with the extracted wavelet. What kind of information extracted wavelet can contain?&lt;/p&gt;&#xA;" OwnerUserId="27481" LastEditorUserId="28050" LastEditDate="2022-08-27T15:58:14.147" LastActivityDate="2022-12-30T11:35:53.060" Title="What is the purpose of wavelet extraction from the seismic trace?" Tags="|geophysics|seismology|seismic|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24210" PostTypeId="2" ParentId="24199" CreationDate="2022-08-22T14:23:53.667" Score="5" Body="&lt;p&gt;I had made a mask of below sea level pixels of the Badwater Basin in &lt;a href=&quot;https://earthscience.stackexchange.com/a/18982/18081&quot;&gt;this answer&lt;/a&gt;. The mask have a few small areas of black pixels (i.e., above sea level pixels) completely surrounded by white pixels (below sea level):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rOAmJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rOAmJ.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I checked &lt;a href=&quot;https://en-gb.topographic-map.com/maps/9z9q/Badwater-Basin/&quot; rel=&quot;nofollow noreferrer&quot;&gt;on the site&lt;/a&gt; provided by @JeopardyTempest, there are indeed a few hills in the area. The largest one is a flat, ~30 m high hill just South of the Salt Creek interpretative trail:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ow2u8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ow2u8.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Looking at it in Google Earth, I believe it is the hill (red ellipse, the red square is just a landmark for reference) pictured on &lt;a href=&quot;https://www.nps.gov/deva/planyourvisit/hiking.htm#SaltCreek&quot; rel=&quot;nofollow noreferrer&quot;&gt;this NPS photograph&lt;/a&gt; (public domain):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9WO62.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9WO62.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vyHXU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vyHXU.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;(image Landsat / Copernicus)&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2022-09-12T12:21:21.543" LastActivityDate="2022-09-12T12:21:21.543" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24211" PostTypeId="2" ParentId="24205" CreationDate="2022-08-22T14:46:16.617" Score="4" Body="&lt;p&gt;As David Hammen's answer illustrates, the dominant tide in different locations vary and the magnitude of each of the tidal constituents will change. The tide in the North Sea is relatively well understood and a map of the dominant constituent (&lt;span class=&quot;math-container&quot;&gt;$M_2$&lt;/span&gt;) is available from many sources. For instance, &lt;a href=&quot;https://www.researchgate.net/publication/234167661_Shallow-Marine_Tidal_Deposits&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reynaud and Dalrymple (2012)&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/n6ttU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/n6ttU.png&quot; alt=&quot;M2 North Sea map&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Map showing the &lt;span class=&quot;math-container&quot;&gt;$M_2$&lt;/span&gt; (principal lunar semidiurnal) tide amphidromic systems in the North Sea. Cotidal lines are perpendicular to the coast, which means that the tidal wave travels parallel to the coast, creating tidal currents that are also coast-parallel. The tidal range increases outward from each amphidromic point (point with zero amplitude for that tidal constituent; &lt;a href=&quot;https://en.wikipedia.org/wiki/Amphidromic_point&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Amphidromic_point&lt;/a&gt;), with the highest tidal ranges within embayments such as the German Bight.&lt;/p&gt;&#xA;&lt;p&gt;Now, if we choose the water level time series (provided by the German &lt;a href=&quot;https://www.bsh.de/EN/Home/home_node.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Federal Maritime and Hydrographic Agency&lt;/a&gt;) at a specific point in the North Sea (Borkum, Germany) for the last couple of weeks, we can see the varying water levels and also the changing magnitude of the peaks depending on whether the main tidal constituents (&lt;span class=&quot;math-container&quot;&gt;$M_2$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$S_2$&lt;/span&gt;) are in phase or out of phase. &lt;a href=&quot;https://i.stack.imgur.com/j2U7n.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/j2U7n.png&quot; alt=&quot;water level at Borkum&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;We can go one step further and conduct a &lt;a href=&quot;https://www.vims.edu/research/units/labgroups/tc_tutorial/tide_analysis.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;harmonic analysis&lt;/a&gt; of the water level time series to quantify the magnitude of each of the tidal constituents that significantly (larger than 5 cm) contribute to the water level oscillations.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;Tide  Description       Period (h)   Amplitude (m)   Phase (degrees GMT)&#xA; &#xA;O1  Lunar diurnal           25.82       0.0930        233.46    &#xA;K1  Lunar/solar diurnal     23.93       0.0875         51.20   &#xA;M2  Lunar semidiurnal       12.42       1.1440        306.06    &#xA;S2  Solar semidiurnal       12.00       0.2978         49.81    &#xA;M4  1st Overtide of M2       6.21       0.0789         82.87   &#xA;M6  2nd Overtide of M2       3.10       0.0658        276.37   &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;The main constituent, as expected, is the &lt;span class=&quot;math-container&quot;&gt;$M_2$&lt;/span&gt; with over 1 meter of amplitude (tidal range will be double that). The second largest constituent, with about 30 cm amplitude, is the &lt;span class=&quot;math-container&quot;&gt;$S_2$&lt;/span&gt;. So when high values of the &lt;span class=&quot;math-container&quot;&gt;$M_2$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$S_2$&lt;/span&gt; coincide in time, the total magnitude will be the addition of the two (~1.44m), while when the 2 are out of phase, then the total magnitude will be decreased. Now as they peak at different times you might have that the space of time between successive high tides will not match either 12.42 hours or 12.00 hours.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, the diurnal tides (&lt;span class=&quot;math-container&quot;&gt;$O_1$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$K_1$&lt;/span&gt;; periods around 24 hours) have a magnitude of about 10 cm and they will also shift the timing of the peak high tide.&lt;/p&gt;&#xA;&lt;p&gt;Finally, the overtides (&lt;span class=&quot;math-container&quot;&gt;$M_4$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$M_6$&lt;/span&gt;; shallow water constituents caused by the interaction of the main components with terrain or other constituents) have magnitudes of about 7 cm in this location and they will also contribute to the intensification of some of the high tides, but should not alter their timing.&lt;/p&gt;&#xA;&lt;p&gt;Reference:&#xA;Reynaud, J.Y. and Dalrymple, R.W., 2012. Shallow-marine tidal deposits. In Principles of tidal sedimentology (pp. 335-369). Springer, Dordrecht.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2022-08-22T14:46:16.617" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24212" PostTypeId="2" ParentId="24199" CreationDate="2022-08-22T17:01:11.160" Score="2" Body="&lt;p&gt;Death Valley in California, USA reaches a depth of 282 ft (86 m) below sea level. It contains a number of hills within the valley and mountains within 1 km of the valley.&lt;/p&gt;&#xA;&lt;p&gt;To meet your qualification, here is Shore Line Butte (188 m) rising from land that is 124 ft below sea level. Note also Cinder Hill, whose &amp;quot;peak&amp;quot; is 29 m below sea level!&lt;/p&gt;&#xA;&lt;p&gt;Map from topographic-map.com:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ijKOS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ijKOS.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="23019" LastActivityDate="2022-08-22T17:01:11.160" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24213" PostTypeId="1" AcceptedAnswerId="24215" CreationDate="2022-08-22T19:24:55.060" Score="2" ViewCount="88" Body="&lt;p&gt;I recently researched about &lt;a href=&quot;https://www.google.com/search?q=superionic%20ice&amp;amp;rlz=1CASFJY_enUS1020&amp;amp;oq=Superionic%20ice&amp;amp;aqs=chrome.0.69i59j0i512l3j0i22i30l5j0i15i22i30.2684j0j9&amp;amp;sourceid=chrome&amp;amp;ie=UTF-8&amp;amp;safe=active&amp;amp;ssui=on&quot; rel=&quot;nofollow noreferrer&quot;&gt;Superionic Ice&lt;/a&gt; which basically is Water under so much pressure and heat that it turns into a black hot ice. I read this &lt;a href=&quot;https://www.livescience.com/stable-superionic-ice-made-first-time&quot; rel=&quot;nofollow noreferrer&quot;&gt;article&lt;/a&gt; about it too. I found out Superionic ice exists inside Earth but I cant make sense of how it got into the core, considering that any water in the ocean basically is sealed off from at least below the mantle because it would immediately evaporate causing bubbles of the vapor to rise until it cools again.&lt;/p&gt;&#xA;" OwnerUserId="21926" LastActivityDate="2022-08-23T11:37:14.207" Title="Is there superionic ice in the earth? and how did it get there?" Tags="|hydrology|geothermal-heat|core|pressure|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24214" PostTypeId="2" ParentId="24199" CreationDate="2022-08-22T20:27:52.630" Score="3" Body="&lt;p&gt;The &lt;a href=&quot;https://az.wikipedia.org/wiki/A%C4%9Fz%C4%B1bir_pal%C3%A7%C4%B1q_vulkan%C4%B1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Aghzibir mud volcano&lt;/a&gt; (Azeri Wikipedia) appears to rise 375 feet above sea level, with its base about 85 feet below sea level, for a prominence of about 460 feet or about 140 meters.  It is located about 18 kilometers south of the city of Älät (Ələt).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/y1bv0.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/y1bv0.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;There are apparently a significant number of &lt;a href=&quot;https://en.wikipedia.org/wiki/Mud_volcanoes_in_Azerbaijan&quot; rel=&quot;nofollow noreferrer&quot;&gt;mud volcanoes in Azerbaijan&lt;/a&gt; (&lt;a href=&quot;https://az.wikipedia.org/wiki/Az%C9%99rbaycan%C4%B1n_pal%C3%A7%C4%B1q_vulkanlar%C4%B1&quot; rel=&quot;nofollow noreferrer&quot;&gt;further information in Azeri&lt;/a&gt;), and perhaps five or six of them of them rise in the region of the country that is otherwise below sea level.  Aghzibir is the tallest of these, at least according to the data from topographic-map.com.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WxFcR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WxFcR.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="4837" LastActivityDate="2022-08-22T20:27:52.630" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24215" PostTypeId="2" ParentId="24213" CreationDate="2022-08-22T23:30:37.657" Score="2" Body="&lt;p&gt;Probably not. While the interior of Earth easily exceeds the &lt;a href=&quot;https://physicsworld.com/a/superionic-ice-phases-could-explain-unusual-magnetic-fields-around-uranus-and-neptune/&quot; rel=&quot;nofollow noreferrer&quot;&gt;40 GPa&lt;/a&gt; pressure required to make superionic ice and we know now that tectonic processes can cycle water deep into the mantle, the temperature profile is likely hot enough to keep the water in a supercritical fluid state. The water may be hot enough in the deep mantle to undergo significant ion formation whether solid or fluid.&lt;/p&gt;&#xA;&lt;p&gt;The supercritical water may be included into diamonds, which retain sufficient internal pressure to &lt;a href=&quot;https://earthscience.stackexchange.com/a/21118/20607&quot;&gt;condense the water as Ice VII&lt;/a&gt; when they come to the surface and cool off.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2022-08-23T11:37:14.207" LastActivityDate="2022-08-23T11:37:14.207" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24216" PostTypeId="1" CreationDate="2022-08-23T09:11:02.227" Score="1" ViewCount="17" Body="&lt;p&gt;One of the routines that I am interested in exploring further is the option of including a riparian zone within the Agricultural Catchments Research Unit (ACRU4) model. Once I add the riparian zone to the model, there are a few options available that need to be populated. While most are self explanatory, I am unsure about how the percent riparian infestation option actually works.&lt;/p&gt;&#xA;" OwnerUserId="27337" LastEditorUserId="27337" LastEditDate="2022-08-24T06:39:44.837" LastActivityDate="2022-08-24T06:39:44.837" Title="ACRU4 PercentRiparianInfestation" Tags="|hydrology|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24217" PostTypeId="1" CreationDate="2022-08-23T09:31:36.247" Score="2" ViewCount="205" Body="&lt;p&gt;&lt;a href=&quot;https://climatefresk.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate Fresk&lt;/a&gt; is a NGO which publishes a card game aimed at educating people about climate change. Card 33 (page 16 of &lt;a href=&quot;https://climatefresk.org/wp-content/uploads/2022/06/Climate-Fresk-EN-US-Adults-V8.1_PRINT.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;this pdf file&lt;/a&gt;) reads (emphasis mine):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Cyclones and atmospheric waves bring wind, waves and low pressure&#xA;conditions. &lt;em&gt;A 1 hectopascal pressure drop causes a 0.4 inches sea&#xA;level rise.&lt;/em&gt; Therefore cyclones can cause marine submersions (or&#xA;coastal flooding), amplified by the sea level rise already caused by&#xA;sea level rise.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Is there really a relationship between pressure drop and sea level rise? And if so, which relationship and what is the mechanism behind it? I find it hard to believe, because &lt;a href=&quot;https://en.wikipedia.org/wiki/Properties_of_water#Compressibility&quot; rel=&quot;nofollow noreferrer&quot;&gt;water has a very low compressibility&lt;/a&gt;, so I don't see how a drop, even big, in atmospheric pressure, could cause such a rise in sea level. The Climate Fresk project claims that all its facts come from the IPCC reports, but I don't know where to start digging...&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;(PS: I'm not questioning the need to educate people about climate change, nor the integrity of the Climate Fresk project; I just want to get the facts straight.)&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2022-08-23T12:07:43.973" LastActivityDate="2022-09-02T19:56:08.407" Title="Is there a relationship between pressure drop and sea level rise?" Tags="|climate-change|sea-level|tropical-cyclone|barometric-pressure|flooding|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24218" PostTypeId="2" ParentId="24216" CreationDate="2022-08-23T10:37:26.953" Score="1" Body="&lt;p&gt;Typically riparian zones in ACRU are configured to receive baseflow from upslope HRUs.  If we consider 3 scenarios:&#xA;(1)    PercentRiparianInfestation=0%: there is no alien vegetation in the riparian zone and all the baseflow from upslope HRU will reach the river.&#xA;(2)    PercentRiparianInfestation=50%: half the riparian zone is infested with alien vegetation, and thus the riparian zone subsoil horizon will be drier, and up to 50% of the baseflow from the upslope HRUs will be retained in the riparian zone subsoil horizon and the remainder will reach the river.&#xA;(3)    PercentRiparianInfestation=100%: the whole riparian zone is infested with alien vegetation, and thus the riparian zone subsoil horizon will be even drier, and up to 100% of the baseflow from the upslope HRUs will be retained in the  riparian zone subsoil horizon and the remainder will reach the river.&lt;/p&gt;&#xA;" OwnerUserId="27486" LastActivityDate="2022-08-23T10:37:26.953" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24219" PostTypeId="2" ParentId="24188" CreationDate="2022-08-23T10:41:58.460" Score="1" Body="&lt;p&gt;Flows above the bankfull capacity of the river and adjusted by the Kin parameter always enters the wetland storage.&lt;/p&gt;&#xA;" OwnerUserId="27486" LastActivityDate="2022-08-23T10:41:58.460" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24220" PostTypeId="1" CreationDate="2022-08-23T11:16:56.547" Score="2" ViewCount="46" Body="&lt;p&gt;I am running the WRSM-Pitman model for the upper reaches of a quaternary catchment (which is smaller than its intended use for full quaternary catchments or larger areas). The total catchment area is 49.2 km2 and the distributed farm dams cover a total area of 0.0754 km2. Are there any guidelines for dam capacities or areas below which their influence is negligible in the model and the dam can be excluded from the runoff module area (i.e. catchment area)?&lt;/p&gt;&#xA;" OwnerUserId="27486" LastActivityDate="2023-05-20T15:01:55.233" Title="Negligible dam capacity to exclude from a runoff module" Tags="|hydrology|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24221" PostTypeId="2" ParentId="24187" CreationDate="2022-08-23T11:46:50.510" Score="0" Body="&lt;p&gt;Yes, it is a typo.&#xA;This is from surface area = a * volume b&#xA;In the modelling tools’ terms, alpha = Anom / Snomb&lt;/p&gt;&#xA;" OwnerUserId="27486" LastActivityDate="2022-08-23T11:46:50.510" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24222" PostTypeId="2" ParentId="24217" CreationDate="2022-08-23T12:16:36.490" Score="3" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Is there really a relationship between pressure drop and sea level rise?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The author of the card was writing about storms at sea. By way of analogy, think of what happens when a person with a significant other flops onto a waterbed. Suppose the significant other, who weighs half as much as the flopper, is already in bed. The significant other may get a bit of a lift from the flop. Another analogy: Think of how you start siphoning gasoline from a gas tank: You reduce the pressure in the siphon. It is the low compressibility of a liquid that makes those responses possible.&lt;/p&gt;&#xA;&lt;p&gt;When there is a storm at sea, it is the waves that are responsible for the bulk of the storm surge. Reduced atmospheric pressure plays a lesser role, but that role does exist. A cyclone whose central pressure is 50 mb less than surrounding areas can cause a huge storm surge. Most of that is wind driven, but about half a meter is pressure driven.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-08-23T12:16:36.490" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24223" PostTypeId="2" ParentId="24220" CreationDate="2022-08-23T12:18:59.653" Score="1" Body="&lt;p&gt;Generally, the area for dams, lakes and wetlands can be excluded from your runoff modules, especially if they exceed about 10% of the catchment.&lt;br /&gt;&#xA;Less than that the effect will be small and the respective components can be included or excluded in the catchment area.&lt;/p&gt;&#xA;" OwnerUserId="27363" LastActivityDate="2022-08-23T12:18:59.653" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24224" PostTypeId="1" CreationDate="2022-08-23T12:58:09.697" Score="1" ViewCount="23" Body="&lt;p&gt;I’m working with the comprehensive wetland module in WRSM-Pitman. However, the variables listed in the wetland tab of the channel module are not referred to in the same way as the variables listed in theory documentation. I am attaching a screenshot of the key parameters in the wetland tab. Please can someone confirm what they are in the theory documentation? Thanks!&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GQyi9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GQyi9.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27486" LastActivityDate="2024-01-18T12:08:51.070" Title="Mapping variables in the model to theory documentation in WRSM-Pitman" Tags="|hydrology|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24225" PostTypeId="5" CreationDate="2022-08-23T13:41:47.033" Score="0" Body="&lt;p&gt;This Tag is for Questions about Rivers and why/how they operate in a certain way, or if the Question talks about a subject or point that revolves around Rivers, streams and et cetera.&#xA;Hydrology Questions can use this tag, or Questions that question the nature of specific rivers,this tag can also be used for nonspecific Questions that just point to Rivers as a whole or general.&lt;/p&gt;&#xA;" OwnerUserId="21926" LastEditorUserId="21926" LastEditDate="2022-08-24T18:32:52.567" LastActivityDate="2022-08-24T18:32:52.567" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24226" PostTypeId="4" CreationDate="2022-08-23T13:41:47.033" Score="0" Body="This Tag is for Questions about Rivers and why/how they operate in a certain way, or if the Question talks about a subject or point that revolves around Rivers, streams and et cetera." OwnerUserId="21926" LastEditorUserId="21926" LastEditDate="2022-08-24T18:32:46.827" LastActivityDate="2022-08-24T18:32:46.827" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24227" PostTypeId="1" CreationDate="2022-08-23T17:57:08.030" Score="1" ViewCount="35" Body="&lt;p&gt;Related to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/24199/are-there-any-land-hills-mountains-with-bases-below-sea-level&quot;&gt;Are there any (land) hills/mountains with bases below sea level?&lt;/a&gt;, are there any peaks or cliff below mean sea level which looks out onto even lower land?&lt;/p&gt;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://elevation.maplogs.com/poi/metsoke_dragot.207681.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://elevation.maplogs.com/poi/metsoke_dragot.207681.html&lt;/a&gt;, Metsoke Dragot almost fits the bill but has 6 m elevation.&lt;/p&gt;&#xA;&lt;p&gt;Even better would be a distinct peak, such as Masada:&#xA;&lt;a href=&quot;http://openstreetmap.org/?mlat=31.316&amp;amp;mlon=35.354&amp;amp;zoom=16&amp;amp;layers=Y&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://openstreetmap.org/?mlat=31.316&amp;amp;mlon=35.354&amp;amp;zoom=16&amp;amp;layers=Y&lt;/a&gt;&#xA;but it's 58 m above sea level.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2mcQC.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2mcQC.jpg&quot; alt=&quot;Masada&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27491" LastEditorUserId="27491" LastEditDate="2022-08-23T18:02:46.263" LastActivityDate="2022-08-23T18:02:46.263" Title="Are there any (land) hills/mountains with *peaks* below sea level?" Tags="|sea-level|mountains|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24228" PostTypeId="1" AcceptedAnswerId="24229" CreationDate="2022-08-23T18:43:45.477" Score="1" ViewCount="177" Body="&lt;p&gt;Imagine the polished / unpolished rocks and stones that people use to decorate their homes and gardens.&lt;/p&gt;&#xA;&lt;p&gt;Are they a renewable resource? Are there plenty of them?&lt;/p&gt;&#xA;&lt;p&gt;If we give 200 pounds of them to each human being alive, would we run out?&lt;/p&gt;&#xA;" OwnerUserId="27492" LastEditorUserId="27492" LastEditDate="2022-08-23T21:14:19.960" LastActivityDate="2022-08-23T21:14:19.960" Title="Are river rocks and stones a renewable resource?" Tags="|rocks|resources|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24229" PostTypeId="2" ParentId="24228" CreationDate="2022-08-23T20:09:20.000" Score="1" Body="&lt;p&gt;&lt;strong&gt;No&lt;/strong&gt;, I think you already know this but Rocks are not a renewable resource. Just because there are a 'lot' of rocks does not mean it is renewable [e.g There are lots of coal here], Rocks come in a limited amount here on Earth. &lt;a href=&quot;https://www.google.com/search?q=Are%20Rocks%20Renewable%3F&amp;amp;rlz=1CASFJY_enUS1020&amp;amp;oq=Are%20Rocks%20Renewable%3F&amp;amp;aqs=chrome..69i57j0i512l2j0i22i30l7.3769j0j7&amp;amp;sourceid=chrome&amp;amp;ie=UTF-8&amp;amp;safe=active&amp;amp;ssui=on&quot; rel=&quot;nofollow noreferrer&quot;&gt;Are Rocks Renewable?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Oh and Yes, It is possible to give 7 billion people 200 pounds of rock each considering the fact that 65 percent of the Earth is made up of Ingenious rocks and 66% is made of basalt, etc. Im 100% sure we can supply 7 Billion Humans with a &lt;a href=&quot;https://www.google.com/search?q=200%20Pound%20Rock&amp;amp;rlz=1CASFJY_enUS1020&amp;amp;oq=200%20Pound%20Rock&amp;amp;aqs=chrome..69i57j0i22i30j0i390.2317j0j9&amp;amp;sourceid=chrome&amp;amp;ie=UTF-8&amp;amp;safe=active&amp;amp;ssui=on&quot; rel=&quot;nofollow noreferrer&quot;&gt;200 pound rock&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;.&lt;/p&gt;&#xA;" OwnerUserId="21926" LastEditorUserId="21926" LastEditDate="2022-08-23T20:17:49.837" LastActivityDate="2022-08-23T20:17:49.837" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24230" PostTypeId="1" AcceptedAnswerId="24478" CreationDate="2022-08-24T00:56:57.513" Score="3" ViewCount="102" Body="&lt;p&gt;On August 21, 2022, the Western Australian town of Cadoux experienced a &lt;a href=&quot;https://www.abc.net.au/news/2022-08-24/cadoux-earthquake-possible-aftershock-from-1979-quake/101362010&quot; rel=&quot;nofollow noreferrer&quot;&gt;magnitude 4.4 earthquake&lt;/a&gt;. According to the report of the incident, that earthquake might be an aftershock of a magnitude 6.1 earthquake the town experienced 43 years earlier, in June 1979.&lt;/p&gt;&#xA;&lt;p&gt;According to Geoscience Australia,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;it was quite common for aftershocks to be experienced decades later, and this most recent tremor could have been an aftershock from the 6.1-magnitude event more than 40 years ago.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;If such delays in the occurrence of aftershocks are quite common what is regarded as being the longest interval between the main quake and aftershock? Secondly, what is the reason for such delays?&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-11-02T01:58:06.833" Title="The longest interval between earthquake main shock &amp; after shock" Tags="|earthquakes|seismology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24231" PostTypeId="2" ParentId="15986" CreationDate="2022-08-24T01:45:26.567" Score="0" Body="&lt;p&gt;It is not necessary for there to be a change in the mass of the Earth to explain changes in surface gravity on the Earth. The only thing that is required is the off-setting of the Earth’s core elements from centricity. This would result in a gravitational gradient around the globe.&#xA;This off-setting has occurred when large surface mass (e.g., Pangea) moved to high latitude, which it did several times. By moving to higher latitude, and therefore closer to the Earth’s spin axis, the Earth’s angular momentum would decrease if nothing offset that movement. This would violate the Law of Conservation of Angular Momentum. The off-setting action was the movement of the Earth’s core elements away from centricity and away from Pangea, thereby lowering surface gravity on and near Pangea. Surface gravity antipodal to Pangea would increase commensurately with the lowering surface gravity on Pangea. In effect, the net surface gravity on the whole Earth would be zero.&#xA;This is explained by my theory ‘The Gravity Theory of Mass Extinction’, a summary of the theory can be found at:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://vixra.org/abs/1709.0208&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://vixra.org/abs/1709.0208&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15493" LastActivityDate="2022-08-24T01:45:26.567" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24232" PostTypeId="1" CreationDate="2022-08-24T08:31:35.293" Score="3" ViewCount="64" Body="&lt;p&gt;I have run a MIKE HYDRO 1D simulation to completion without any errors being flagged. How do I check for any instability within the model or whether the simulated results are realistic?&lt;/p&gt;&#xA;" OwnerUserId="27486" LastActivityDate="2023-01-23T08:07:55.877" Title="MHYDRO Hydrodynamics (MIKE HYDRO)" Tags="|hydrology|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24234" PostTypeId="2" ParentId="20171" CreationDate="2022-08-25T04:30:51.763" Score="3" Body="&lt;p&gt;A physical explanation makes no sense at all as we know the temperature continues to fall. In addition, all the surfaces that emit IR at night also do during the day, as IR radiation is just a function of temperature.&lt;/p&gt;&#xA;&lt;p&gt;The answer has to be local environmental, biological or psychological.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Local environmental&lt;/strong&gt; - humidity can rise at night, and air currents fall reducing evaporation and thus raising perceived temperature.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Biological&lt;/strong&gt; - In a poorly ventilated room, humidity can rise at night and body warmth can also raise the temperature.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Psychological&lt;/strong&gt; - Your sensitivity to heat may be higher.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="27502" LastEditorUserId="6467" LastEditDate="2023-02-01T14:44:07.980" LastActivityDate="2023-02-01T14:44:07.980" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24235" PostTypeId="1" AcceptedAnswerId="24624" CreationDate="2022-08-25T04:35:55.213" Score="2" ViewCount="318" Body="&lt;p&gt;I believe some of the Global Forecast System (GFS) &lt;a href=&quot;https://www.nco.ncep.noaa.gov/pmb/products/gfs/gfs.t00z.pgrb2.0p25.f003.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;parameters&lt;/a&gt; are point values while others are average values over an interval. For example, the parameter DSWRF (Downward Short-Wave Radiation Flux) is labeled as a &amp;quot;0-3 hour ave&amp;quot;. Does this mean that for forecast hour 3 from the GFS, the DSWRF value is the average for the interval of hour 3 to hour 6? Is anything not labeled as an average a point value? Is there documentation that answers these questions (I can't find any)? I ask because the documentation for &lt;a href=&quot;https://github.com/SolarArbiter/solarforecastarbiter-core/blob/23ac3c7a699f720fb642c3cc7d1acb83b486c2a6/solarforecastarbiter/reference_forecasts/models.py#L81&quot; rel=&quot;nofollow noreferrer&quot;&gt;solarforecastarbiter-core&lt;/a&gt; claims that &amp;quot;Cloud cover from GFS is an interval average with ending label&amp;quot; (line 88). If this were true for my DSWRF example above, the forecast for hour 3 would be the average for the interval of hour 0 to hour 3 rather than from hour 3 to hour 6.&lt;/p&gt;&#xA;&lt;p&gt;Thank you for your help!&lt;/p&gt;&#xA;" OwnerUserId="27501" LastActivityDate="2022-12-13T11:41:08.357" Title="Understanding GFS Parameter Averaging Times" Tags="|gfs|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24236" PostTypeId="2" ParentId="24232" CreationDate="2022-08-26T06:24:01.353" Score="2" Body="&lt;p&gt;Checking the hydraulics of your 1D MHYDRO setup is usually a good starting point. This can be done by opening the 1D result file in Mike View. Click on the “select profile” icon and then click a start and end point of the river segment that you are interested in. Thereafter select “yes” to close the profile selection so that the profile can be drawn. The data type to be selected is “water level”. Once the profile has been drawn, you should notice that the profile gradually decreases in water level from left to right. This is the type of trend you’re looking for.&lt;/p&gt;&#xA;" OwnerUserId="27337" LastActivityDate="2022-08-26T06:24:01.353" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24237" PostTypeId="2" ParentId="24224" CreationDate="2022-08-26T09:56:27.613" Score="0" Body="&lt;p&gt;I’ll list them as model definitions to theory documentation variables:&lt;/p&gt;&#xA;&lt;p&gt;Area of wetland at bankfull level of channel: Anom&lt;/p&gt;&#xA;&lt;p&gt;Volume of wetland at bankfull level: Snom&lt;/p&gt;&#xA;&lt;p&gt;Power of area-volume relationship: b&lt;/p&gt;&#xA;&lt;p&gt;Bankfull capacity of river channel: Qbf (in wetland inflow equation)&lt;/p&gt;&#xA;&lt;p&gt;Proportion of flow in excess of bankfull into wetland: Kin&lt;/p&gt;&#xA;&lt;p&gt;Proportion of wetland vol. (over bankfull) into channel: Kout&lt;/p&gt;&#xA;" OwnerUserId="27363" LastActivityDate="2022-08-26T09:56:27.613" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24238" PostTypeId="1" CreationDate="2022-08-26T12:52:29.550" Score="2" ViewCount="42" Body="&lt;p&gt;We are working on a MIKE-SHE coupled MIKE-Hydro model for a small wetland in South Africa. One of the major issues is that it has zero-flux boundaries around the model domain in the saturated zone (SZ), and therefore ignores any inflow from its boundaries in the SZ. This is unrealistic as this is a very fine-scale model, and there is very likely to be movement of water subsurface into the wetland and this may well be significant. We therefore need to correct the SZ boundary conditions.&lt;/p&gt;&#xA;&lt;p&gt;One idea to do this was to use a nested approach, building a larger model for the catchment which would then aim to simulate the boundary conditions of the smaller model domain. The reason we didn't just work with a larger model to start with is that we thought it may mask the small scale effects we were wanting to investigate. We thought this was the best approach, however we have no idea how to output the SZ flow from the larger model, to input it into the boundary of the smaller model. Given the functionality of this model and all the grids we are able to export, it must be possible to do this. But how? Can we input a shapefile and ask for a timeseries (dfs0) file to be extracted for that domain from the large model? And then input this into the SZ boundary of the smaller model? Or is there another way to do this?&lt;/p&gt;&#xA;&lt;p&gt;I enclose a map of the region of interest showing the nested approach, the smaller model domain is indicated by the yellow polygon, and the larger model domain by the blue polygon. The scale of the map is also indicated. &lt;a href=&quot;https://i.stack.imgur.com/hJefz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hJefz.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27288" LastActivityDate="2022-09-27T22:07:56.063" Title="MIKE-SHE hydrological model: How to export SZ flow from a larger model to import into a smaller, nested model to inform SZ boundary conditions" Tags="|hydrology|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24239" PostTypeId="5" CreationDate="2022-08-26T13:16:35.730" Score="0" Body="&lt;p&gt;Greenhouse gases are gases that trap heat into the Earth's atmosphere. These gases are carbon dioxide (CO&lt;sub&gt;2&lt;/sub&gt;), methane (CH&lt;sub&gt;4&lt;/sub&gt;), nitrous oxide (N&lt;sub&gt;2&lt;/sub&gt;O), hydrofluorocarbons (HFCs) perfluorocarbons (PFCs) sulfur hexafluoride (SF&lt;sub&gt;6&lt;/sub&gt;), nitrogen trifluoride (NF&lt;sub&gt;3&lt;/sub&gt;) and et cetera.&lt;/p&gt;&#xA;&lt;p&gt;Any questions related to these gases in the atmosphere or the subject of greenhouse gases qualify.&lt;/p&gt;&#xA;" OwnerUserId="21926" LastEditorUserId="2470" LastEditDate="2022-08-27T01:06:26.723" LastActivityDate="2022-08-27T01:06:26.723" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24240" PostTypeId="4" CreationDate="2022-08-26T13:16:35.730" Score="0" Body="Greenhouse gases are gases that trap heat into the Earth's atmosphere these gases are Carbon dioxide (CO2), Methane (CH4), Nitrous oxide (N2O), Hydrofluorocarbons (HFCs) Perfluorocarbons (PFCs) Sulfur hexafluoride (SF6), Nitrogen trifluoride (NF3) and et cetera." OwnerUserId="21926" LastEditorUserId="21926" LastEditDate="2022-08-27T01:06:39.553" LastActivityDate="2022-08-27T01:06:39.553" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24241" PostTypeId="2" ParentId="24209" CreationDate="2022-08-27T15:57:26.290" Score="6" Body="&lt;p&gt;&lt;strong&gt;We're usually not interested in the wavelet &lt;em&gt;per se&lt;/em&gt;, but we need to know it in order to understand how the seismic trace relates to geological properties we are interested in.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;According to the so-called &lt;a href=&quot;https://subsurfwiki.org/wiki/Convolutional_model&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;strong&gt;convolutional model&lt;/strong&gt; of seismic&lt;/a&gt;, a trace &lt;span class=&quot;math-container&quot;&gt;$s(t)$&lt;/span&gt; (the amplitude is a function of time &lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt;) has three main components, so to speak:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ s(t) = r(t) \ast w(t) + n $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; is the reflectivity of the earth, &lt;span class=&quot;math-container&quot;&gt;$w$&lt;/span&gt; is the wavelet, &lt;span class=&quot;math-container&quot;&gt;$n$&lt;/span&gt; is random noise, and &lt;span class=&quot;math-container&quot;&gt;$\ast$&lt;/span&gt; denotes a mathematical operation called &lt;a href=&quot;https://en.wikipedia.org/wiki/Convolution&quot; rel=&quot;nofollow noreferrer&quot;&gt;convolution&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;strong&gt;reflectivity&lt;/strong&gt; of the earth is very useful geological information. Reflectivity is a function of the &lt;strong&gt;impedance contrast&lt;/strong&gt; at a boundary (e.g. between two beds) and impedance is, in turn, a function of important rock properties, especially density and the speed of sound in the rock. Both of these properties can help us deduce the rock type, porosity, fluid type, and so on, and other related properties can tell us about thin beds and fractures and other interesting things.&lt;/p&gt;&#xA;&lt;p&gt;The problem with getting at the rock property information from the seismic trace is that it's all tangled up with the wavelet via the convolutional operator (there's noise too, but we can't do much about that.)&lt;/p&gt;&#xA;&lt;h3&gt;So why do we need the wavelet?&lt;/h3&gt;&#xA;&lt;p&gt;Two reasons:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Forward modeling.&lt;/strong&gt; With a wavelet, we can try to &lt;strong&gt;forward model&lt;/strong&gt; the seismic. For example we can measure, or guess, the impedance, calculate the reflectivity, and convolve with a wavelet to have a good guess at what the seismic might look like. This will result in &lt;strong&gt;synthetic seismic&lt;/strong&gt;. We can use this to, for example, try to figure out which bed in a borehole is which event in a seismic volume (we call this process 'well tying'.)&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Inversion.&lt;/strong&gt; Or, we can use the wavelet to get at the geology from the seismic data we measured. If we can estimate the wavelet, we can try to untangle it, or &lt;strong&gt;deconvolve&lt;/strong&gt; it, from the seismic trace and get at the juicy geological stuff.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;So, having the wavelet, or being able to make a good guess at it, is useful. There are several ways to do it, e.g. see &lt;a href=&quot;https://wiki.seg.org/wiki/Wavelet_estimation_for_well_ties&quot; rel=&quot;nofollow noreferrer&quot;&gt;the SEG wiki&lt;/a&gt;. But it's a bit of an art and can be frustrating to get right... so a lot of people give up and use a standard off-the-shelf wavelet like a &lt;a href=&quot;https://subsurfwiki.org/wiki/Ricker_wavelet&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ricker&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="28050" LastEditorUserId="28050" LastEditDate="2022-12-30T11:35:53.060" LastActivityDate="2022-12-30T11:35:53.060" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24242" PostTypeId="1" CreationDate="2022-08-28T07:32:28.030" Score="1" ViewCount="112" Body="&lt;p&gt;Because humans can not reach the inside of the Earth, there might be possibilities like in some stories that there is life under Earth?&lt;/p&gt;&#xA;" OwnerUserId="27517" LastEditorUserId="2470" LastEditDate="2022-08-28T11:21:16.763" LastActivityDate="2022-09-03T14:52:50.427" Title="How to prove that there is no life undergound?" Tags="|geologic-layers|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24245" PostTypeId="2" ParentId="9488" CreationDate="2022-08-28T17:35:33.463" Score="-1" Body="&lt;p&gt;Water may not be lost from the earth’s atmosphere; however, an apparent loss does exist from the “free” water in the atmosphere. It has been absorbed by the increase in living beings (people an animals) and therefore not available in abundant quantities as in previous generations. This is a simple, yet profound, explanation as to why there are more areas with droughts and water shortages than in any known time in history.&lt;/p&gt;&#xA;" OwnerUserId="27523" LastEditorUserId="27523" LastEditDate="2022-08-28T17:36:29.513" LastActivityDate="2022-08-28T17:36:29.513" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24246" PostTypeId="2" ParentId="24238" CreationDate="2022-08-28T21:02:49.910" Score="1" Body="&lt;p&gt;The most suitable approach would depend on what data is available. If there is groundwater level data close to the upslope boundaries of the target wetland or information about groundwater gradients in the landscape, or the gradient across the wetland itself, this data can be used to determine a head or gradient boundary at the edges of the wetland. This would not entail modeling the whole contributing area.&#xA;If there is reason to believe that the groundwater gradient across the wetland and surrounding area more or less follows the gradient of the topography, this could be used to assign gradient boundaries around the wetland.&lt;/p&gt;&#xA;&lt;p&gt;I am assuming there is not groundwater data like this for your site and that is why you want to model the surrounding area. It is hard to tell from the image what is being used to delineate the larger area being shown around the target wetland. For the larger model, I would suggest modelling the contributing catchment of the wetland down to the outlet of the wetland or a point further down the stream for which there is streamflow data. One could use a smaller surrounding area if there was groundwater level data to set the boundary conditions for it.&lt;/p&gt;&#xA;&lt;p&gt;Groundwater flux timeseries can be obtained for a &amp;quot;cross section&amp;quot; line drawn in the gridded groundwater model output. This can be used to determine a timeseries of flux across the boundary into the target wetland area on the up-gradient side and out of the wetland on the down-gradient side, if a gradient exists.&#xA;Alternatively a timeseries of heads can be extracted for given cross section lines to be input as time varying head boundaries.&#xA;Values can be averaged to create dfs0 timeseries for different boundary segments.&#xA;If there is head data from boreholes or piezometers to compare to the modelled values, using the head values in the boundary condition would be a good option.&lt;/p&gt;&#xA;&lt;p&gt;The MIKE-SHE Manual v2, section &amp;quot;11.18.22 Outer boundary conditions&amp;quot;, states that for the &amp;quot;Head&amp;quot; boundary option, one can input a &amp;quot;time varying dfs2 file of head, which is typically extracted from a regional results file. This can be done using the MIKE Zero Toolbox Extraction tool: 2D Grid from 3D files. MIKE SHE then interpolates in both time and space from the .dfs2 file to the local head boundary at each local time step.&amp;quot; (DHI)&#xA;This is not something I have attempted myself, so cannot give guidance on how to do this using the Toolbox.&lt;/p&gt;&#xA;&lt;p&gt;When modelling the larger catchment you may also need to allow there to be a head, gradient, or flux boundary at the downstream end of the catchment to get reasonable results.&lt;/p&gt;&#xA;" OwnerUserId="27371" LastActivityDate="2022-08-28T21:02:49.910" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24247" PostTypeId="1" AcceptedAnswerId="24248" CreationDate="2022-08-29T13:51:34.543" Score="1" ViewCount="73" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;So control of the country’s finances required control of its main&#xA;trading centres. &lt;strong&gt;To that end, in 1550 Gustav Vasa founded a new&#xA;harbour city on the northern shore of the Gulf of Finland, at Vanda&#xA;fors (stream) in the parish of Helsinge.&lt;/strong&gt; It was called Helsingfors,&#xA;still its Swedish name, known in Finnish as Helsinki. (bolds by me)&lt;/p&gt;&#xA;&lt;p&gt;A history of Finland by Henrik Meinander&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In the bolded sentence, author says that &amp;quot;Gustav Vasa founded a city at Vanda fors&amp;quot; and translator (who translated the book from Swedish) added the word &amp;quot;stream&amp;quot; in the brackets. The original version of the text didn't have the word &amp;quot;stream&amp;quot;. When I google it I have found &lt;a href=&quot;https://sv.wikipedia.org/wiki/Vandaforsen&quot; rel=&quot;nofollow noreferrer&quot;&gt;Vandaforsen&lt;/a&gt; in wikipedia. But this wikipedia page has no English version so I can not come to a conclusion about the geographical category of this place (Vandaforsen). I don't know if it is the name of a stream, a city, or what?&lt;/p&gt;&#xA;&lt;p&gt;Is there any special meaning in the separation of the &amp;quot;Vanda&amp;quot; and &amp;quot;fors&amp;quot;? In the original text also these words are separated.&lt;/p&gt;&#xA;&lt;p&gt;When I translated the word &amp;quot;fors&amp;quot; form Swedish I have found that one of its meanings is &amp;quot;stream&amp;quot;. But I am not sure whether or not a city can be founded at a stream? It that possible?&lt;/p&gt;&#xA;&lt;p&gt;Ultimately my question is what does separated &amp;quot;Vanda fors&amp;quot; mean and is its meaning any different from &amp;quot;Vandaforsen&amp;quot;? And what is the geographical category of the place called &amp;quot;Vandaforsen&amp;quot;?&lt;/p&gt;&#xA;" OwnerUserId="27454" LastEditorUserId="2470" LastEditDate="2022-08-29T17:53:49.110" LastActivityDate="2022-08-29T17:54:47.113" Title="What is the geographical category of the place called &quot;Vandaforsen&quot;?" Tags="|geography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24248" PostTypeId="2" ParentId="24247" CreationDate="2022-08-29T14:22:06.687" Score="0" Body="&lt;p&gt;I do not have access to the original text which could shed some additional light on the word(s). But, the word &amp;quot;fors&amp;quot; means &amp;quot;rapid&amp;quot; in Swedish. Vanda is likely a place name so &amp;quot;Vanda fors&amp;quot; means &amp;quot;the rapid at Vanda&amp;quot; or &amp;quot;the Vanda rapid&amp;quot;, the latter meaning a rapid in the stream called Vanda. In Swedish this would normally be written as &amp;quot;Vandafors&amp;quot; not as two words. However, in older texts it was not uncommon to separate the words so it is possible that the original text states &amp;quot;Vanda fors&amp;quot;. Since a major difference between Swedish and English is that word constructions like the above are joined whereas in English words are normally separated with space (Vandaforsen vs. Vanda rapid), it is thus possible that the translator chose to separate the words as part of the translation. That, however, seems a little far fetched.&lt;/p&gt;&#xA;&lt;p&gt;So the place was apparently a stream with a rapid or a place by that stream called Vanda.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="2470" LastEditDate="2022-08-29T17:54:47.113" LastActivityDate="2022-08-29T17:54:47.113" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24249" PostTypeId="1" AcceptedAnswerId="25767" CreationDate="2022-08-29T14:33:26.640" Score="2" ViewCount="54" Body="&lt;p&gt;Synthetic trace generated with deterministic wavelet gives a higher correlation with real seismics.&lt;/p&gt;&#xA;&lt;p&gt;Though it's more accurate for seismic well ties than statistical wavelet, but there is always an option for creating synthetic trace with statisctical wavelet ?&lt;/p&gt;&#xA;&lt;p&gt;My question is : Why to use statistical wavelet, if deterministic is more accurate for well tying?&lt;/p&gt;&#xA;" OwnerUserId="27481" LastActivityDate="2023-11-25T05:52:30.963" Title="If deterministic wavelet is better for well ties , why do people use statistical wavelet too for wellties?" Tags="|seismology|seismic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24250" PostTypeId="1" CreationDate="2022-08-29T19:45:36.710" Score="3" ViewCount="160" Body="&lt;p&gt;Are there any types of wind or waves caused and produced only and exclusively by Earth's rotation? Not influenced by Earth rotation, but produced solely by it?&lt;/p&gt;&#xA;&lt;p&gt;In the case of waves, are Rossby waves &lt;a href=&quot;https://oceanservice.noaa.gov/facts/rossby-wave.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt; and Kelvin waves &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Kelvin_wave&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt; examples of that? Like, imagine the Earth as a single planet with no Sun (so no influence by the Sun's heat), no moon (so no tides) and no planetary internal hot core (so no influence by the heat from Earth's internal core). Then assume that somehow water is still liquid and air in its gas form, then, just by Earth's rotation, would there be any waves or wind (even if they would be very subtle)? Would there still be Rossby waves or Kelvin waves for instance? (I found a comment to a question in Quora that indicates that the answer is basically &amp;quot;yes&amp;quot; &lt;a href=&quot;https://www.quora.com/Are-there-any-types-of-waves-caused-produced-only-and-exclusively-by-Earths-rotation-Are-Rossby-waves-and-Kelvin-waves-examples-of-that/answer/Oliver-Milatovic?comment_id=285392316&amp;amp;comment_type=2&amp;amp;__filter__=all&amp;amp;__nsrc__=notif_page&amp;amp;__sncid__=30510430344&amp;amp;__snid3__=41211295831&quot; rel=&quot;nofollow noreferrer&quot;&gt;3&lt;/a&gt;, but no sources are given, so I would like to see if someone could verify that)&lt;/p&gt;&#xA;" OwnerUserId="27529" LastEditorUserId="27529" LastEditDate="2022-09-01T01:16:53.610" LastActivityDate="2022-09-01T01:16:53.610" Title="Are there any types of winds or waves that are produced just by Earth's rotation?" Tags="|atmosphere|wind|waves|ocean-currents|earth-rotation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24251" PostTypeId="5" CreationDate="2022-08-29T22:06:24.973" Score="0" Body="&lt;p&gt;A mass extinction is an event where several species go extinct. Any questions related to the mass extinction of several species qualify for this tag.&#xA;[e.g. Dinosaur Mass Extinction Event]&lt;/p&gt;&#xA;" OwnerUserId="21926" LastEditorUserId="2470" LastEditDate="2022-08-30T00:28:48.147" LastActivityDate="2022-08-30T00:28:48.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24252" PostTypeId="4" CreationDate="2022-08-29T22:06:24.973" Score="0" Body="A Mass Extinction is an event where several species go extinct. Any questions related to the mass extinction of several species qualify for this tag." OwnerUserId="21926" LastEditorUserId="2470" LastEditDate="2022-08-30T00:26:53.300" LastActivityDate="2022-08-30T00:26:53.300" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24253" PostTypeId="2" ParentId="24242" CreationDate="2022-08-29T22:29:32.513" Score="1" Body="&lt;p&gt;The Kola Superdeep Borehole is &lt;a href=&quot;https://www.google.com/search?q=kora%20superdeep%20borehole%20height%20in%20kilometers&amp;amp;rlz=1CASFJY_enUS1020&amp;amp;ei=YzoNY7z7KOmIptQPpYWW4AU&amp;amp;ved=0ahUKEwj8uM3Bie35AhVphIkEHaWCBVwQ4dUDCA4&amp;amp;uact=5&amp;amp;oq=kora%20superdeep%20borehole%20height%20in%20kilometers&amp;amp;gs_lcp=Cgdnd3Mtd2l6EAMyBQghEKsCMggIIRAeEBYQHToHCAAQRxCwAzoGCAAQHhAWOgUIABCGAzoHCCEQoAEQCkoECEEYAEoFCEASATFKBAhGGABQ3QRY7yVg1idoBnABeACAAckBiAHAE5IBBjAuMTcuMpgBAKABAcgBCMABAQ&amp;amp;sclient=gws-wiz&amp;amp;safe=active&amp;amp;ssui=on&quot; rel=&quot;nofollow noreferrer&quot;&gt;12.2 Kilometers&lt;/a&gt;. At the bottom of the Kola Superdeep Borehole it gets pretty hot, and there is no soil or much organic matter since it would probably have turned into oil on the way down due to pressure and heat.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;How to prove there is no life underground?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I get the impression that you do not think there is any life underground, however there is, there is life gathered in soil, rock and wood deep underground, miles underground that have biofilms with cells on them (Read Sandford Underground Research Facility's research on &lt;a href=&quot;https://sanfordlab.org/feature/life-underground&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;)&#xA;Extremophiles exist, in bubbling boiling hot water on land so it would be reasonable to assume there must be some underground. However deep enough life cannot be supported anymore due to the following:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Lack of food or nutrients to take in&lt;/li&gt;&#xA;&lt;li&gt;Heat rises (combined with lack of food/nutrients) will not encourage life growth&lt;/li&gt;&#xA;&lt;li&gt;High Pressure, unable to actually make its way so deep underground&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;So I conclude that life is available deep enough underground (couple miles down) and at a certain point life stops because of what I noted above.&lt;/p&gt;&#xA;" OwnerUserId="21926" LastEditorUserId="21926" LastEditDate="2022-09-03T14:52:50.427" LastActivityDate="2022-09-03T14:52:50.427" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24254" PostTypeId="1" AcceptedAnswerId="24507" CreationDate="2022-08-29T22:39:58.337" Score="5" ViewCount="72" Body="&lt;p&gt;I was reading this &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9488/how-much-water-is-the-atmosphere-losing-to-space&quot;&gt;Question&lt;/a&gt; earlier about how if water is getting lost into space and one of the answers said that (paraphrase) the Earth lost about enough water for the oceans to reduce by 12 cm, if the Earth lost that amount of water, could it make up for the loss by receiving Water from Space? I did research about this&#xA;&lt;a href=&quot;https://www.google.com/search?q=how%20did%20earth%20get%20its%20water&amp;amp;rlz=1CASFJY_enUS1020&amp;amp;oq=how%20did%20Earth%20get%20its%20water&amp;amp;aqs=chrome.0.0i512l2j0i390.6038j0j7&amp;amp;sourceid=chrome&amp;amp;ie=UTF-8&amp;amp;safe=active&amp;amp;ssui=on&quot; rel=&quot;noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Far from the Sun, where temperatures are low, water formed icy objects such as comets, while closer to the Sun water reacted with rocky materials to form hydrated minerals. It's thought that the mostly likely way that planet Earth inherited its water was from asteroids and comets crashing into it.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Is the Earth still receiving Water this way?&lt;/p&gt;&#xA;" OwnerUserId="21926" LastEditorUserId="2470" LastEditDate="2022-08-30T00:32:28.133" LastActivityDate="2022-11-12T17:16:42.710" Title="How much water is the atmosphere receiving" Tags="|atmosphere|hydrology|water|water-vapour|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24255" PostTypeId="1" CreationDate="2022-08-30T12:14:41.213" Score="1" ViewCount="50" Body="&lt;p&gt;Since I am from the Niger delta, where crude oil is mostly seen ... when we pump water and I try drinking it, it reeks of fuel ... how can I confirm it to be crude locally before alerting the oil company?&lt;/p&gt;&#xA;" OwnerUserId="27536" LastEditorUserId="2470" LastEditDate="2022-08-30T12:46:02.657" LastActivityDate="2022-08-30T12:46:02.657" Title="I perceive fuel in my bore hole water" Tags="|geology|groundwater|pollution|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24257" PostTypeId="2" ParentId="24250" CreationDate="2022-08-30T23:55:14.490" Score="5" Body="&lt;p&gt;Yes. Such a thing is called an &lt;a href=&quot;https://glossary.ametsoc.org/wiki/Inertial_oscillation&quot; rel=&quot;noreferrer&quot;&gt;inertial oscillation&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Kelvin waves are not examples of inertial oscillations. Kelvin waves balance the earth's rotation against the normal force of a topographic boundary. While some sources say that Rossby waves are inertial waves, they are not actually inertial oscillations in the strictest sense. One example of an inertial oscillation is the formation of the &lt;a href=&quot;https://meteor.geol.iastate.edu/classes/mt407/powerpoint/mteor407_10_LLJ.pdf&quot; rel=&quot;noreferrer&quot;&gt;low level jet&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Mathematically speaking, an inertial oscillation can be described by the equation &lt;span class=&quot;math-container&quot;&gt;$\frac{d \vec{v}}{dt}=f \hat{k} \times \vec{v}$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2022-08-30T23:55:14.490" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24261" PostTypeId="1" CreationDate="2022-08-31T13:17:15.780" Score="1" ViewCount="43" Body="&lt;p&gt;I have taken an upper air sounding from UoW Database and currently calculating the Brunt-Vaisala frequency (the 'squared' one, at the moment) using MetPy across several stations for some basic synoptic purposes.&lt;/p&gt;&#xA;&lt;p&gt;The minimal &lt;em&gt;(at some point)&lt;/em&gt; and reproducible code runs like this&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;    import metpy.calc as mpcalc&#xA;    import matplotlib.pyplot as plt&#xA;    import numpy as np&#xA;    from datetime import datetime&#xA;    from metpy.units import units, pandas_dataframe_to_unit_arrays&#xA;    from siphon.simplewebservice.wyoming import WyomingUpperAir&#xA;    &#xA;    stations = ['RPLI', 'RPUB', '98433', 'RPMP', 'RPVP', 'RPMD'] #6 stations&#xA;    station_data = {}&#xA;    date = datetime(2016, 8, 14, 0)&#xA;    &#xA;    for station in stations:&#xA;        print(f'Getting {station}')&#xA;        df = pandas_dataframe_to_unit_arrays(WyomingUpperAir.request_data(date, station))&#xA;        df['theta'] = mpcalc.potential_temperature(df['pressure'], df['temperature'])&#xA;        df['bv_squared'] = mpcalc.brunt_vaisala_frequency_squared(df['height'], df['theta'])&#xA;        station_data[station] = df&#xA;    &#xA;    mean_bv = []&#xA;    for station in stations:&#xA;        df = station_data[station]&#xA;        keep_idx = (df['height'] &amp;gt;= 1000 * units.m) &amp;amp; (df['height'] &amp;lt;= 5 * units.km)&#xA;        mean_bv.append(np.mean(df['bv_squared'][keep_idx]).m)&#xA;    &#xA;    plt.title(&amp;quot;Atmospheric Stability&amp;quot;)&#xA;    plt.plot(mean_bv)&#xA;    plt.show()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;which produces a simple plot like this&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LTreT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LTreT.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I would like to ask on how to smooth out those 'lines'/data, like by applying interpolation? I'm a bit novice, thus I look forward to your help and responses.&lt;/p&gt;&#xA;" OwnerUserId="27543" LastEditorUserId="27543" LastEditDate="2022-08-31T13:19:18.093" LastActivityDate="2022-08-31T13:19:18.093" Title="Applying spline interpolation for Brunt-Vaisala frequency" Tags="|meteorology|python|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24262" PostTypeId="1" CreationDate="2022-08-31T17:35:01.830" Score="1" ViewCount="19" Body="&lt;p&gt;I'm interested in this question because we invariably get persistent headlines year after year about drought.  If it's true that the Earth receives roughly the same amount of precipitation every year, then drought is only a matter of distribution, where some places get more than normal, some get normal amounts, and some get lesser amounts of precipitation.  On the other hand, if the Earth receives significant variances in precipitation from year to year, then drought is not necessarily a distribution problem and can be a result of a low precipitation period affecting larger areas at once.&lt;/p&gt;&#xA;" OwnerUserId="27545" LastActivityDate="2022-08-31T18:19:31.107" Title="How much variation in total precipitation does the Earth receive each year?" Tags="|precipitation|drought|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24263" PostTypeId="2" ParentId="24262" CreationDate="2022-08-31T18:19:31.107" Score="1" Body="&lt;p&gt;Rainfall over large areas and drought are very much linked to the &lt;a href=&quot;https://en.wikipedia.org/wiki/El_Ni%C3%B1o&quot; rel=&quot;nofollow noreferrer&quot;&gt;El Nino&lt;/a&gt;/&lt;a href=&quot;https://en.wikipedia.org/wiki/La_Ni%C3%B1a&quot; rel=&quot;nofollow noreferrer&quot;&gt;La Nina&lt;/a&gt;, Southern Oscillation Index in the Pacific Ocean and its equivalent in the Indian Ocean, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Indian_Ocean_Dipole&quot; rel=&quot;nofollow noreferrer&quot;&gt;Indian Ocean Dipole&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;During a La Nina, cold surface waters occur in the eastern Pacific Ocean and warm waters occur to the east of Australia. Such conditions tend to bring drought to the Americas and excessive rainfall to the east coast of Australia, particularly the north east.&lt;/p&gt;&#xA;&lt;p&gt;An El Nino event is the opposite - warm waters in the eastern Pacific Ocean and cooler waters off the east of Australia with rainfall in the Americas and drought in eastern Australia.&lt;/p&gt;&#xA;&lt;p&gt;The Indian Ocean Dipole (IOD) is the equivalent in the Indian Ocean. With a negative IOD. Cold surface waters occur off east Africa and warm waters to the north west of Australia. This brings drought to east Africa and more rainfall from the north west of Australia to the south east of Australia.&lt;/p&gt;&#xA;&lt;p&gt;In the latter part of 2021 and the first half of 2022, there was a La Nina event in the Pacific and a negative IOD in the Indian Ocean which has resulted in drought in east Africa and the USA, while eastern Australian has had two or three major flooding events due to excessive rain.&lt;/p&gt;&#xA;&lt;p&gt;It is unusual to have three successive La Nina events, usually the maximum is two, however a &lt;a href=&quot;https://www.msn.com/en-us/weather/topstories/la-ni%C3%B1a-could-enter-rare-third-straight-year-here-s-what-that-means/ar-AAWFlw0&quot; rel=&quot;nofollow noreferrer&quot;&gt;third such event&lt;/a&gt; has been identified, as of late August 2022.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-08-31T18:19:31.107" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24264" PostTypeId="2" ParentId="24242" CreationDate="2022-08-31T19:14:24.583" Score="-1" Body="&lt;p&gt;It cannot be proven that won't be life underneath as if some day underneath material is exposed to the surface of the Earth, then will be very much possibilities of holding life on it. I'm talking about the future, but it's nearly impossible along the next 1 billion years an underground square kilometer not hosting life at least one time (unless if it's the material under the active currents limit layer), beneath it, if the temperature reachs a value major than the max. temperature DNA could resist then won't be the life we know, but it is not sure then if there could be another forms of &amp;quot;life&amp;quot; not based on DNA (like an advanced AI, more or less degree of &amp;quot;Intelligence&amp;quot;, I'm not referring to AI as a conscious form of life, as it could be compared too with a program moving up or down depending of temperature, in fact we are this kind of form of life, but we do not understand how our brains work and that makes the difference).&lt;/p&gt;&#xA;" OwnerUserId="27508" LastEditorUserId="27508" LastEditDate="2022-09-01T16:13:30.773" LastActivityDate="2022-09-01T16:13:30.773" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24265" PostTypeId="1" CreationDate="2022-09-01T00:51:31.463" Score="5" ViewCount="338" Body="&lt;p&gt;I've been looking at reconstructions of the extent of ice at the last glacial maximum, while each map differs slightly (two shown below), most show a massive North American ice sheet, extending as far south as present-day New York. In western and central Europe, the ice sheets don't extend quite as far south. This isn't surprising, as western Europe is generally warmer than North America on the same latitude - a fact that is typically attributed to the action of the Gulf Stream.  What's really perplexing is Siberia and the rest of east Eurasia. These areas seem to have virtually no ice sheets, despite being much further north than comparable areas in North America or Eurasia. Additionally, they're far enough east that I can't imagine they'd be strongly affected by the gulf stream.  What would explain the differences?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AUV6B.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AUV6B.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ek57X.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ek57X.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27551" LastEditorUserId="6467" LastEditDate="2023-01-30T17:36:40.987" LastActivityDate="2023-01-30T20:32:28.497" Title="Why was the ice age more severe in North America than in Eurasia?" Tags="|paleoclimatology|ice-age|ice-sheets|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24266" PostTypeId="1" AcceptedAnswerId="24270" CreationDate="2022-09-01T02:06:16.323" Score="1" ViewCount="37" Body="&lt;p&gt;Optical remote sensing technology is commonly used for forest biomass estimation. The NDVI is used to define greenness. But how can we tell about biomass after capture only canopy area from above? Is it only outermost layer, right? Can only NDVI represent the all biomass of tree?&lt;/p&gt;&#xA;" OwnerUserId="27378" LastActivityDate="2022-09-02T11:16:07.510" Title="Forest canopy structure" Tags="|remote-sensing|forest|biomass|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24267" PostTypeId="1" CreationDate="2022-09-01T05:35:49.770" Score="3" ViewCount="99" Body="&lt;p&gt;I do understand why the seismic velocity decreases with temperature and increases with pressure, but I am not really familiar with the relationship between the velocity with Poisson's ratio. I understand the main idea of the Poisson's ratio and how it relates to the deformation, but I do not understand how it contributes to the wave velocity and also how does it change with temperature and pressure?&lt;/p&gt;&#xA;" OwnerUserId="27553" LastActivityDate="2022-09-07T12:47:58.600" Title="Seismic velocity relations" Tags="|geology|geophysics|seismology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24268" PostTypeId="2" ParentId="24265" CreationDate="2022-09-01T10:20:59.910" Score="2" Body="&lt;p&gt;For ice sheet formation you need both cold conditions and precipitation, if it's cold but dry you will get permafrost, but not enough snow to build up glaciers.&lt;/p&gt;&#xA;&lt;p&gt;This map of precipitation during the last age suggests eastern Eurasia was particularly dry in the north:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ti0ki.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ti0ki.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/Category:Ice_age_maps#/media/File:Lgm_ccsm4_precipitation_annual.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikimedia.org&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21672" LastEditorDisplayName="user28185" LastEditDate="2023-01-30T20:32:28.497" LastActivityDate="2023-01-30T20:32:28.497" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24269" PostTypeId="1" CreationDate="2022-09-01T17:02:20.427" Score="1" ViewCount="10" Body="&lt;p&gt;Suppose I have a variable that is a classification of something. In this example, it is a classification of soil texture:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;String soil_class(depth=3);&#xA;  :string system = &amp;quot;USC&amp;quot;;&#xA;&#xA;data = &amp;quot;Organic clays&amp;quot;, &amp;quot;Silty gravels&amp;quot;, &amp;quot;Silty gravels&amp;quot;, &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Are there existing standards (CF or otherwise) that describe the name that should be given to an attribute that provides the classification system that is used (in this example, I use the attribute name &lt;code&gt;system&lt;/code&gt;)?.&lt;/p&gt;&#xA;&lt;p&gt;There are similar applications for metadata (instead of data from a variable) where a secondary attribute indicates the vocabulary or classification system used for the primary metadata attribute:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;In the &lt;a href=&quot;https://ioos.github.io/ioos-metadata/ioos-metadata-profile-v1-2.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;IOOS standard&lt;/a&gt; &lt;code&gt;contributor_role_vocabulary&lt;/code&gt; is used for &lt;code&gt;contributor_role&lt;/code&gt;&lt;/li&gt;&#xA;&lt;li&gt;In the &lt;a href=&quot;https://wiki.esipfed.org/Attribute_Convention_for_Data_Discovery_1-3&quot; rel=&quot;nofollow noreferrer&quot;&gt;ACDD standard&lt;/a&gt; &lt;code&gt;standard_name_vocabulary&lt;/code&gt; is used for &lt;code&gt;standard_name&lt;/code&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;but to reiterate, these refer back to metadata attributes, not data. I am unaware of any convention that provides a &amp;quot;classification_vocabulary&amp;quot; equivalent for classified data, but want to be sure before I make an ad-hoc one.&lt;/p&gt;&#xA;" OwnerUserId="14348" LastActivityDate="2022-09-01T17:02:20.427" Title="Is there a standardized metadata attribute for describing which classification system is used for a (string) variable?" Tags="|netcdf|cf-metadata|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24270" PostTypeId="2" ParentId="24266" CreationDate="2022-09-02T11:14:19.813" Score="0" Body="&lt;p&gt;Not an expert in this field but I found this in quick Google search:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/eg8rt.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eg8rt.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Reference: &lt;a href=&quot;https://doi.org/10.2307/1942049&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.2307/1942049&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I think from line 8 the answer to your question begins.&lt;/p&gt;&#xA;" OwnerDisplayName="user27562" LastEditorDisplayName="user27562" LastEditDate="2022-09-02T11:16:07.510" LastActivityDate="2022-09-02T11:16:07.510" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24271" PostTypeId="2" ParentId="24217" CreationDate="2022-09-02T11:31:27.310" Score="2" Body="&lt;p&gt;Not an expert but a quick google search gave me this answer: &lt;a href=&quot;https://doi.org/10.1002/2015GL064580&quot; rel=&quot;nofollow noreferrer&quot;&gt;Inverted barometer contributions to recent sea level changes along the northeast coast of North America&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Sweet and Zervas [2011] interpret anomalously high sea levels along the northeast coast of the United&#xA;States during the 2009/2010 cool season without reference to the inverted barometer effect; they reconcile&#xA;this event in terms of anomalous northeasterly winds over the Gulf of Maine connected to sea level pressure changes over the southeastern United States and eastern Canada linked to El Niño. Similarly, Goddard&#xA;et al. [2015] reason that extreme sea level rise along Atlantic Canada and New England between 2008 and&#xA;2010 was largely connected to changes in the overturning circulation and wind stress anomalies related to exceptional values of the North Atlantic Oscillation; these authors posit that the &lt;strong&gt;inverted barometer contributed only ∼15% to the extreme rise.&lt;/strong&gt; Our findings, based on four different pressure data sets, give inverted&#xA;barometer contributions around 50% (Figure 3), or roughly 3 times larger than those found by Goddard et al.&#xA;[2015], and indicate that isostatic effects were of central importance to this unique sea level rise event.&amp;quot;&lt;/p&gt;&#xA;" OwnerDisplayName="user27562" LastEditorUserId="18088" LastEditDate="2022-09-02T19:56:08.407" LastActivityDate="2022-09-02T19:56:08.407" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24272" PostTypeId="2" ParentId="17958" CreationDate="2022-09-02T13:35:06.577" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Doesn't that mean that it froze quickly, centuries ago, and stayed frozen until now?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Not necessarily.  In places where permafrost exists, the thickness of the 'active layer' (the layer above permafrost that thaws seasonally) is relatively stable. This means that if you &lt;em&gt;add&lt;/em&gt; material and raise the ground surface by burying organic material and soil, the top of permafrost will raise. So you can accumulate organic material in permafrost in a stable climate!&lt;/p&gt;&#xA;&lt;p&gt;Also, consider that the process of organic material decaying once buried can take quite a lot of time, meaning that burial rates don't have to be as rapid as you might think. Modern-day sphagnum peat bogs accumulate a lot of organic material in them even in temperate climates.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;What process caused such a sudden, centuries-long freeze? Don't we need to know this before we understand why it's reversing now? Presumably we humans had nothing to do with the freeze!&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;As stated above, the drop in temperatures doesn't have to be rapid because organic material can accumulate in permafrost even in a stable climate.&lt;/p&gt;&#xA;" OwnerUserId="14348" LastActivityDate="2022-09-02T13:35:06.577" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24273" PostTypeId="2" ParentId="16514" CreationDate="2022-09-02T13:46:48.337" Score="3" Body="&lt;p&gt;There is &lt;a href=&quot;https://glossary.ametsoc.org/wiki/Pereletok&quot; rel=&quot;nofollow noreferrer&quot;&gt;actually a name for this phenomenon&lt;/a&gt;: &amp;quot;pereletok&amp;quot;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;How deep would the frost have to go before it was too deep for it to thaw fully over summer?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This depends more on the thermal properties of the ground and the subsequent air temperatures than it does on the frost penetration depth. Some important factors to consider (in addition to those stated by Camilo) would be:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;The difference between the thawed and frozen thermal conductivities of the ground&lt;/strong&gt;.  If it is easy to take heat out of the ground and hard to put it back in, then that will encourage the presence of permafrost&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;The presence of ice in the ground&lt;/strong&gt; It takes a lot of energy to melt ice. If the winter is particularly cold and causes ice to form in the ground (or if glacial ice is somehow buried), this can help to preserve permafrost.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;There is one thing in Camilo's answer that should be clarified:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Permafrost is ground that is &lt;em&gt;below 0 C for more than 2 years&lt;/em&gt;. It is purely a thermal criterion; it doesn't need to be frozen or even contain any water at all (solid bedrock can be permafrost).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="14348" LastActivityDate="2022-09-02T13:46:48.337" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24274" PostTypeId="1" AcceptedAnswerId="24275" CreationDate="2022-09-02T15:41:21.983" Score="1" ViewCount="41" Body="&lt;p&gt;&lt;a href=&quot;https://www.bbc.com/future/article/20220830-the-new-science-of-recycling-human-poo&quot; rel=&quot;nofollow noreferrer&quot;&gt;This&lt;/a&gt; BBC article says biosolids make soil &amp;quot;fluffier&amp;quot;, among other benefits. How?&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Adding humanure also changes soil structure, making it more resilient, preventing erosion and balancing out moisture, says Moss. It makes dirt fluffier, so water passes through easier. Conversely, in drought conditions, this also helps it retain water. The less compact soils are also softer, enabling seedlings to take faster and grow stronger roots, producing better yields.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="22632" LastActivityDate="2022-09-03T14:50:00.133" Title="How does humanure make soil &quot;fluffier&quot;?" Tags="|soil-science|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24275" PostTypeId="2" ParentId="24274" CreationDate="2022-09-03T00:58:46.093" Score="1" Body="&lt;h3&gt;What are Biosolids and how do they work?&lt;/h3&gt;&#xA;&lt;p&gt;a &lt;a href=&quot;https://www.google.com/search?q=biosolid&amp;amp;source=lmns&amp;amp;bih=617&amp;amp;biw=1366&amp;amp;rlz=1CASFJY_enUS1020&amp;amp;hl=en&amp;amp;sa=X&amp;amp;ved=2ahUKEwikvcqZsvf5AhVdgokEHT5MAyMQ_AUoAHoECAEQAA&amp;amp;safe=active&amp;amp;ssui=on&quot; rel=&quot;nofollow noreferrer&quot;&gt;biosolid&lt;/a&gt; is a product of the sewage treatment processes and is a semi-solid sludge of &lt;em&gt;organic matter&lt;/em&gt;, nutrient-rich organic compounds. Here I list several reasons as to why biosolids would make the soil 'fluffier' and and better&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;As I said earlier biosolids are typically made out of organic matter, organic matter is carbon-based and biosolids are usually biological material (decomposed feces, urine and et cetera).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;If you are not familiar with the normal decomposition processs it is a biological material (banana, apple, feces and et cetera) that is decomposed by microbes, molds, fungi and etc&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;em&gt;biosolids are biological and/or organic material so what I just stated above applies to biosolids as well&lt;/em&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Think of what you flush down a toilet or what goes down a sewer drain, are those things carbon based and biological? (human feces is an organic-compound and it goes in the sewers)&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;So now we know that biosolids are like other organic-compounds, how does this maker the soil fluffier. When something undergoes decomposition it turns into fresh brand-new soil, and quite obviously this new soil would be much more higher-quality and better than over-used old soil.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.atsdr.cdc.gov/HAC/landfill/html/ch2.html#:%7E:text=The%20more%20organic%20waste%20present,by%20the%20bacteria%20during%20decomposition.&quot; rel=&quot;nofollow noreferrer&quot;&gt; Here it states&lt;/a&gt; that organic material in a landfill produce gases due to decomposition so it makes sense that the same process would happen underground where microbial decomposition can release gases in the soil thus making the soil fluffier&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;So I can conclude that biosolids do, in fact help soil and make it fluffier and better.&lt;/p&gt;&#xA;" OwnerUserId="21926" LastEditorUserId="21926" LastEditDate="2022-09-03T14:50:00.133" LastActivityDate="2022-09-03T14:50:00.133" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24276" PostTypeId="2" ParentId="24199" CreationDate="2022-09-03T06:01:46.673" Score="4" Body="&lt;p&gt;UPDATE:&#xA;Ok I think I have found the best candidate, I'm amazed there actually is a true mountain completely surrounded by land below sea level, whose topographic prominence is therefore higher than its actual elevation. It's a volcano in Ethiopia, Ale Bagu: (&lt;a href=&quot;https://www.peakbagger.com/peak.aspx?pid=77241&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.peakbagger.com/peak.aspx?pid=77241&lt;/a&gt;), there is very limited information on wikipedia for such a unique mountain (&lt;a href=&quot;https://en.wikipedia.org/wiki/Ale_Bagu&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Ale_Bagu&lt;/a&gt;) &lt;a href=&quot;https://i.stack.imgur.com/iEVYm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iEVYm.jpg&quot; alt=&quot;Ale Bagu Elevation 1013m, Topographic prominence 1066m&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Prior comment:&#xA;Just to add to the above, I happened to be carrying out the same investigation on topographic maps, and then decided to look up online and came across this thread. A couple of other relevant locations:&#xA;There seems to be a bunch around the Jordan valley, with some protruding above sea level, as the OP requested, e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Masada&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Masada&lt;/a&gt;, as well as some that remain below sea level, but are perhaps a couple of hundred feet prominence above the surroundings, notably Tel Kazir by the sea of Galilee.&#xA;Also a notable mention of the Salton Buttes at the Salton sea (another below sea level location in California): &lt;a href=&quot;https://en.wikipedia.org/wiki/Salton_Buttes&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Salton_Buttes&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27566" LastEditorUserId="27566" LastEditDate="2022-09-10T02:44:27.213" LastActivityDate="2022-09-10T02:44:27.213" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24277" PostTypeId="1" CreationDate="2022-09-03T08:35:04.667" Score="1" ViewCount="71" Body="&lt;p&gt;Assuming a spinning Earth of 6378.1 km (3963 mi) radius, how much farther would the additional momentum carry a stone if I threw it in the direction of the Earth's rotation (i.e. eastwards) when standing on the equator at sea level, than if I threw it with the same force the other direction? How much is the difference in percent or permille?&lt;/p&gt;&#xA;" OwnerUserId="27567" LastEditorUserId="27567" LastEditDate="2022-09-03T08:42:59.860" LastActivityDate="2022-09-03T13:21:14.563" Title="If I stood on the equator and threw a stone in direction of rotation, how much farther would the stone go than if I threw it the other direction?" Tags="|earth-rotation|equator|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24278" PostTypeId="1" AcceptedAnswerId="24281" CreationDate="2022-09-03T08:36:55.067" Score="3" ViewCount="88" Body="&lt;p&gt;Please correct me if I have said something wrong, as it might be the answer to my question. Also, these are all the things that I've learned through self-studying, so I might have been mislead.&lt;/p&gt;&#xA;&lt;p&gt;Anyways,&lt;/p&gt;&#xA;&lt;p&gt;The plate tectonics theory states that the Earth's lithosphere have been and is still (slowly) moving since about 3.4 billion years ago. It is proved by many evidences, most notably global distributions or locations of volcanoes, earthquake epicenters, and mountain belts. When superimposed, these locations somewhat forms the plate boundaries of a proposed supercontinent pangea.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/u9O9a.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/u9O9a.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Photo credits: &lt;a href=&quot;https://www.learner.org/wp-content/interactive/dynamicearth/tectonicsmap/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.learner.org/wp-content/interactive/dynamicearth/tectonicsmap/index.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;From my understanding, volcanoes, earthquake epicenters, and mountain belts are all the products of colliding plates.&lt;/p&gt;&#xA;&lt;p&gt;If this is so, and if it is true that the plates moved somewhat &lt;em&gt;away&lt;/em&gt; from each other (since it was once a supercontinent, then it is now &lt;em&gt;scattered&lt;/em&gt;), then why is it that there are volcanoes, earthquake epicenters, and mountain belts--products of collision--in areas where a collision didn't happen?&lt;/p&gt;&#xA;&lt;p&gt;Like, the plates moved away right? And collision, from my understanding, is the &lt;em&gt;crashing&lt;/em&gt; of two plates, and collision ≠ moving away. So why is it that they formed despite no plates collided to each other?&lt;/p&gt;&#xA;" OwnerUserId="27568" LastEditorUserId="27568" LastEditDate="2022-09-03T08:37:15.573" LastActivityDate="2022-12-29T14:29:59.303" Title="Why are the supposed-to-be results of collision and/or subduction formed in an area where collision and/or subduction didn't happen?" Tags="|geophysics|plate-tectonics|tectonics|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24279" PostTypeId="2" ParentId="24277" CreationDate="2022-09-03T11:40:25.533" Score="3" Body="&lt;p&gt;You, the stone, all locations on the equator, and the atmosphere a little above the equator are all moving with basically the same momentum initially.  When you throw it, in the big picture, it gains total momentum (if throwing eastward) or loses total momentum (if throwing westward).  But because its course and momentum do not shift it from being along the equator, its altered  momentum will not have any &amp;quot;carryon&amp;quot; momentum difference horizontally that imparts apparent motion.  In other words, for the east/west aspect DIRECTLY, the Earth's rotation will have no impact, it will continue doing what it was doing.  You can consider its initial momentum from the Earth and its added momentum from the throw entirely separately... it will hit where you expect it to hit from this factor.  The eastward or westward component have no bearing at all because it remains at the Equator.&lt;/p&gt;&#xA;&lt;p&gt;It's like being on a moving train, and tossing a rock to your friend within the train car.  Everything is moving the same rate, there is no difference.&lt;br /&gt;&#xA;&lt;strong&gt;So directly (from the eastward or westward direct of the throw), there is no difference at all along the equator.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, there is still one difference in rotation rates for paths at the Equator.  As the rock goes UP, it will have less velocity than required at that height (because the horizontal velocity needed to maintain the same rotation rate is more), and so it will lag behind.  It will wind up west of where it should have... regardless of whether you threw it east or west.  This difference is only a factor of the vertical component of the throw.&lt;/p&gt;&#xA;&lt;p&gt;That said, if you're throwing it, it's going to be a pretty quick trajectory. Short distances and times have very little Coriolis deflection.&lt;/p&gt;&#xA;&lt;p&gt;The amount of deflection becomes a nonlinear PDE (as early Coriolis alteration in the path changes both its subsequent landing time and its upcoming Coriolis deflection), so I don't believe you can derive a simple formula for the true percentage change.&lt;/p&gt;&#xA;&lt;p&gt;But for a typical throw attempting an east or west motion, you won't have much vertical velocity, and gravity is very good at removing that component quickly.  The deflection for a typical strong human's throw will be on the order of millimeters or less (this is true wherever you throw it on Earth).&lt;/p&gt;&#xA;&lt;p&gt;The percentage of horizontal deflection would actually be infinite if thrown straight up (since a millimeter divided by 0 is still a &amp;quot;giant&amp;quot; change), and will quickly become a minuscule percentage if any horizontal component is given to the throw; a footballer's pass will not be noticeably altered by Coriolis anywhere on Earth.  Air resistance/wind will be much much more significant factors.  Even for missiles, which have much more velocity and so can fly for much longer times and thereby reach areas with significantly different rotational momentum, Coriolis deflection will only be on the order of a small percent.  But a few percent can mean a few km/miles for intercontinental trajectories... kind of important for a targeted missile!&lt;/p&gt;&#xA;&lt;p&gt;Only things that can stay &amp;quot;aloft&amp;quot; &amp;quot;permanently&amp;quot;... i.e. fluids (gases, and also liquids)... does Coriolis have a relatively giant impact (causing air that should otherwise flow directly from high to low pressure into air that rotates along isobars)&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-09-03T13:21:14.563" LastActivityDate="2022-09-03T13:21:14.563" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="24280" PostTypeId="1" CreationDate="2022-09-03T18:42:46.583" Score="1" ViewCount="140" Body="&lt;p&gt;I was thinking of crushing up some common limestone for microminerals because the water where I live has nearly zero calcium content. So I read about the trace elements of limestone and It says chromium is common at about 30ppm, and chromium VI is toxic, but it only occurs at tectonic boundaries and high-energy industrial processing.&lt;/p&gt;&#xA;&lt;p&gt;If I crush up mountain limestone which is full of white calcite, what kind of nasty chemicals could result from that, compared to drinking water from a village fountain from the same area?&lt;/p&gt;&#xA;" OwnerUserId="3315" LastEditorUserId="2470" LastEditDate="2022-09-06T18:29:09.493" LastActivityDate="2023-03-14T14:32:19.817" Title="What kind of chromium is in common limestone?" Tags="|geology|water|mineralogy|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24281" PostTypeId="2" ParentId="24278" CreationDate="2022-09-03T20:26:21.450" Score="2" Body="&lt;p&gt;I think there are two aspects to consider.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Before moving away when a supercontinent breaks up, plates have to collide to form this supercontinent in the first place. This process, called an orogeny, builds mountains. And mountains take a long, long time to erode. For example, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Variscan_orogeny&quot; rel=&quot;nofollow noreferrer&quot;&gt;Variscan orogeny&lt;/a&gt; happened when Laurussia and Gondwana collided to form Pangaea. This formed many mountains that still exist today, in Europe (French Massif Central, Bohemian Massif...) or in North America (Appalachian). Breaking up the supercontinent doesn't mean that you erase the mountains that were formed when the supercontinent formed. So &lt;strong&gt;even if plates move away, you keep old mountains&lt;/strong&gt;.&lt;/li&gt;&#xA;&lt;li&gt;When plates move away from a broken supercontinent, they can eventually meet and collide. For example, when Pangaea broke up, Asia and India both moved away, but at some point Asia began to move North and collided with Asia, forming the Himalayas. So &lt;strong&gt;even if plates move away, they can collide and form new mountains&lt;/strong&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Supercontinents actually follow &lt;a href=&quot;https://en.wikipedia.org/wiki/Supercontinent_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;a cycle&lt;/a&gt; of formation and breaking up, and both phases can lead to mountain building.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2022-09-03T20:26:21.450" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24282" PostTypeId="2" ParentId="24280" CreationDate="2022-09-04T00:57:11.880" Score="3" Body="&lt;p&gt;Whether the chromium is Cr(III) or Cr(VI) while it's in the rock is less important than what could happen when the material is dissolved and thus exposed to air (which can also be dissolved or entrained in water). According to the Pourbaix diagram given by Mahiya and Lofrano&lt;a href=&quot;https://www.researchgate.net/publication/262763956_Heavy_metals_in_water_their_adverse_health_effects_and_Biosorptive_removal_A_review&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;, oxygen (represented by the upper dashed line) can oxidize Cr(III) to Cr(VI). If your limestone sample has chromium, you may want to prudently assume it acts as a source of Cr(VI) when dissolved under our atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/M2qPr.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/M2qPr.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Chromium tends to occur in higher concentrations in mafic rock like basalt and sediments derived from them. So if you can remove such impurities from your limestone, the risk from chromium (and other heavy metals that tend to get into mafic rock) would be less.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Mahiya, Suresh &amp;amp; Lofrano, Giusy &amp;amp; Sharma, Sanjay. (2014). &amp;quot;Heavy metals in water, their adverse health effects and Biosorptive removal: A review.&amp;quot; &lt;em&gt;International Journal of Chemistry&lt;/em&gt;. &lt;strong&gt;3&lt;/strong&gt;. 132-149. &lt;a href=&quot;https://www.researchgate.net/publication/262763956_Heavy_metals_in_water_their_adverse_health_effects_and_Biosorptive_removal_A_review&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/publication/262763956_Heavy_metals_in_water_their_adverse_health_effects_and_Biosorptive_removal_A_review&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2023-03-14T14:32:19.817" LastActivityDate="2023-03-14T14:32:19.817" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24283" PostTypeId="1" AcceptedAnswerId="24287" CreationDate="2022-09-04T07:11:59.817" Score="2" ViewCount="540" Body="&lt;p&gt;Apparently according to the &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Parkes_process&quot; rel=&quot;nofollow noreferrer&quot;&gt;Parkes Process&lt;/a&gt; silver is 3000 times more soluble in zinc than in lead. So why is it that most silver is obtained from galena?&lt;/p&gt;&#xA;&lt;p&gt;Edit:&#xA;“ Silver mainly occurs as a contaminant in chalcopyrite and galena, important ores of copper and lead, respectively.” &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Silver_mining&quot; rel=&quot;nofollow noreferrer&quot;&gt;Silver mining&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This Wikipedia page cites a few sources as well. So maybe it isn’t most, but a great deal of it is found in galena.&lt;/p&gt;&#xA;&lt;p&gt;Also the page for &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Galena&quot; rel=&quot;nofollow noreferrer&quot;&gt;galena&lt;/a&gt; mentions that it’s an important source of silver.&lt;/p&gt;&#xA;" OwnerUserId="27571" LastEditorUserId="27571" LastEditDate="2022-09-04T17:41:05.647" LastActivityDate="2022-09-05T04:49:21.490" Title="Why is silver found mainly in lead" Tags="|geology|geochemistry|mineralogy|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24284" PostTypeId="1" CreationDate="2022-09-04T08:56:21.773" Score="2" ViewCount="25" Body="&lt;p&gt;Mesopotamia was part of the Fertile Crescent, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Assur&quot; rel=&quot;nofollow noreferrer&quot;&gt;Assur&lt;/a&gt; was an Assyrian city in Mesopotamia for roughly 1500 years, but it looks like &lt;a href=&quot;https://whc.unesco.org/en/list/1130/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; now (barely any vegetation, pure desert):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Y2vLu.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Y2vLu.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;What was the Fertile Crescent like 10k BCE (or even before that) until it became a desert like this? Was it in fact &amp;quot;flowing streams and lush vegetation&amp;quot; at one point? Where can I find more description of the environment during this time, and why it changed. Wondering next, if it &lt;em&gt;was&lt;/em&gt; lush with streams and vegetation, why it became a desert.&lt;/p&gt;&#xA;&lt;p&gt;I am new to digging into the ancient Near East, but haven't found anything saying what it was really possibly like back then.&lt;/p&gt;&#xA;" OwnerUserId="784" LastActivityDate="2022-09-04T08:56:21.773" Title="What was the physical environment like in the Fertile Cresent between 10k BCE and 1 CE?" Tags="|climate-change|climate|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24286" PostTypeId="1" CreationDate="2022-09-04T20:58:57.437" Score="1" ViewCount="32" Body="&lt;p&gt;Let's assume I have 3 different climate models for a specific region that project the temperature. I also have the observations of that region for the same time frame(the real temperatures). My readings are daily. Which metric should I use and why? For example :&lt;/p&gt;&#xA;&lt;p&gt;Mean Average is not really useful since because of the sign readings can cancel each other out&#xA;Absolute Mean Average. I mostly think this is the most useful. However, I am puzzled because when I subtracted the projections - observations I noticed that around 500 readings out of the 13500 have a big difference (around 10 degrees of Celcius). Should I include these outliers or just delete them?&#xA;Does Squared Mean Error and Root Squared Mean Error provide me with any valuable insight?&#xA;EDIT : Hey everyone. Thank you for the feedback. My question at hand is that I am given 4 different bias correction methods and I want to create a multi model with equal voting. I want to present which bias correction method is more suitable: quantile mapping and scaled distribution mapping (Gamma and Normal Corrections). In order to do that(and to show that bias correction is useful) I found the Mean Absolute Error, Squared Mean Error and Root Squared Mean Error to find the most accurate model. Then performed bias correction with all methods and used the same metrics again. Also I created the multi model(basically it s the average of the models). Thus I created a plot with a single model, a multi model and a multi model with bias correction. With these metrics, I saw that the most accurate was the scaled distribution mapping with normal corrections which makes sense since temperature follows a normal distribution over the years (basically it has the lowest Mean Absolute Error) I based the comparison on MAE because I read that we usually use it to compare models etc&lt;/p&gt;&#xA;&lt;p&gt;Or should I just plot the outcomes of each bias correction method and see which one follows the distribution better?&lt;/p&gt;&#xA;" OwnerUserId="27575" LastActivityDate="2022-09-04T20:58:57.437" Title="Which metric to use for estimating accuracy of a climate model?" Tags="|climate-models|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24287" PostTypeId="2" ParentId="24283" CreationDate="2022-09-05T04:49:21.490" Score="7" Body="&lt;p&gt;This may not be a complete answer, but a big misconception here may be that silver is found &amp;quot;in&amp;quot; lead. It would be more correct to say that silver is more concentrated in the lead ore mineral galena, which is different than metallic lead. The solubility of silver in zinc or lead likely refers to the properties of silver-zinc and silver-lead &lt;em&gt;alloys&lt;/em&gt;, whereas most natural occurrences are in sulphide minerals (galena for lead; sphalerite for zinc).&lt;/p&gt;&#xA;&lt;p&gt;This realization makes it more reasonable that silver (as Ag&lt;sup&gt;+&lt;/sup&gt;) would be found preferentially in galena, whose structure can accommodate the relatively large Pb&lt;sup&gt;2+&lt;/sup&gt; ion, as opposed to the smaller (Zn,Fe)&lt;sup&gt;2+&lt;/sup&gt; site in sphalerite. In fact, the two metals (lead and zinc) occur together very frequently in economically important deposit types like seafloor volcanogenic massive sulphide and carbonate-hosted lead-zinc (aka MVT) deposits. This may even be compatible with the metallogenic association between silver and zinc you imply by their higher miscibility; it's just that silver is less easily incorporated into the zinc sulphide lattice than that of its common partner lead.&lt;/p&gt;&#xA;" OwnerUserId="27389" LastActivityDate="2022-09-05T04:49:21.490" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24289" PostTypeId="1" CreationDate="2022-09-06T11:57:38.480" Score="2" ViewCount="60" Body="&lt;p&gt;I'm interested in a material known as sepiolite. Wikipedia has the articles &lt;a href=&quot;https://en.wikipedia.org/wiki/Sepiolite&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;sepiolite&lt;/em&gt;&lt;/a&gt; in English and &lt;a href=&quot;https://es.wikipedia.org/wiki/Sepiolita#Formaci%C3%B3n&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Sepiolita.&lt;/em&gt;&lt;/a&gt; in Spanish.&lt;/p&gt;&#xA;&lt;p&gt;I'm more a person who tends to be more mathematical.  But I'm interested in this amazing material because it makes me think about life and death itself, almost eschatological (being connected with the aridity and dryness of the desert, which is my mind is the death of rivers and the life around them; the collection or purifying of fossil fuels...)&lt;/p&gt;&#xA;&lt;p&gt;I've read the sepiolite Wikipedia, and it talks some about the formation, but I would like to know more details about the formation, and particularly the timeline of the formation.  If possible (it is not obligatory) with a diagram/drawing explaining the process of formation of sepiolite as time goes on.  Feel free to add any further references if you have them.&lt;/p&gt;&#xA;&lt;p&gt;I add also that I know the article &lt;a href=&quot;https://en.wikipedia.org/wiki/Palaeochannel&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Palaeochannel&lt;/em&gt;&lt;/a&gt; from Wikipedia that refers information about what is a palaeoriver, if this can be useful for answer my question.&lt;/p&gt;&#xA;" OwnerUserId="27578" LastEditorUserId="27578" LastEditDate="2023-02-20T15:38:46.717" LastActivityDate="2023-03-01T08:01:56.233" Title="How does a sepiolite deposit form?" Tags="|sedimentology|minerals|climatology|stratigraphy|paleogeography|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24290" PostTypeId="2" ParentId="24267" CreationDate="2022-09-06T15:07:33.580" Score="0" Body="&lt;p&gt;In terms of the seismic velocities, the Poisson's ratio can be expressed as the following, under the assumption the material is isotropic and homogeneous:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/i9tDq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/i9tDq.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="24528" LastActivityDate="2022-09-06T15:07:33.580" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24291" PostTypeId="1" CreationDate="2022-09-07T03:25:52.570" Score="2" ViewCount="65" Body="&lt;p&gt;There's news going around (&lt;em&gt;e.g.&lt;/em&gt; &lt;a href=&quot;https://news.google.com/articles/CBMib2h0dHBzOi8vYWJjbmV3cy5nby5jb20vSW50ZXJuYXRpb25hbC9hbnRhcmN0aWNhcy1tZWx0aW5nLWRvb21zZGF5LWdsYWNpZXItcmFpc2Utc2VhLWxldmVscy0xMC9zdG9yeT9pZD04OTQxNTQwNdIBc2h0dHBzOi8vYWJjbmV3cy5nby5jb20vYW1wL0ludGVybmF0aW9uYWwvYW50YXJjdGljYXMtbWVsdGluZy1kb29tc2RheS1nbGFjaWVyLXJhaXNlLXNlYS1sZXZlbHMtMTAvc3Rvcnk_aWQ9ODk0MTU0MDU?hl=en-US&amp;amp;gl=US&amp;amp;ceid=US%3Aen&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt;) that the melting of the Thwaites glacier may cause sea levels to rise by 10 feet. Is that true and not exaggerated? How is the calculation made? They said the glacier is the size of Florida so I'm looking at a world map but having trouble imagining a mass that small (compared with the rest of the Earth) can affect such a large surface area of water by that much.&lt;/p&gt;&#xA;&lt;p&gt;From the link in case the article disappears:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This makes the ice shelves on Thwaites and Pine Island more sensitive to extreme climate change in the ocean, atmosphere and sea ice. If Thwaites and Pine Island were to destabilize, several of the neighboring areas would also fall apart, causing a widespread collapse, the scientists said. Thwaites alone could cause sea levels to rise about 10 feet, the scientists said.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;To attempt a back of the envelope calculation (and show some effort): The surface area of the Earth is said to be about 510 million km^2, 71% of it water as opposed to land, so 362 million km^2. This times the sea level change of 10 feet (0.003048 km) yields a volume of 1.1 million km^3. The Thwaites glacier's basin area is said to be about 192,000 km^2. (I know I haven't accounted for the difference in volume of liquid water versus ice, and probably other factors, but I'm just trying to see if the answer is within an order of magnitude of what makes sense to me.) To have a volume of 1.1 million km^3 with a basin area of 192,000 km^2, the glacier would have to be over 5 km in height. That's more than 10 Empire State Buildings, or nearly twice the Burj Khalifa, in height. Are glaciers actually that massive? I can't seem to find out the height of this glacier anywhere for some reason. Probably for a good reason (it's complicated).&lt;/p&gt;&#xA;" OwnerUserId="6007" LastEditorUserId="6007" LastEditDate="2022-09-07T03:37:23.003" LastActivityDate="2022-09-07T03:37:23.003" Title="How is sea level rise due to a glacier melting calculated?" Tags="|climate-change|sea-level|glaciology|antarctica|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24292" PostTypeId="1" CreationDate="2022-09-07T04:27:43.630" Score="1" ViewCount="46" Body="&lt;p&gt;I'm trying to understand how CO&lt;sub&gt;2&lt;/sub&gt; emissions are calculated in the Land Use category &amp;quot;Forest Land Remaining Forest Land&amp;quot;. There are several subcategories, the one with the biggest impact seems to be &amp;quot;Change in Biomass&amp;quot; both above and below ground and I would like to understand this subcategory.&lt;/p&gt;&#xA;&lt;p&gt;I came to this as a bit skeptical of the large negative values (i.e. forests are absorbing large amounts of CO&lt;sub&gt;2&lt;/sub&gt;) being quoted in various government reports and I would like to have a rough understanding how this number is calculated.&lt;/p&gt;&#xA;&lt;p&gt;The clearest reference I have found is from &lt;a href=&quot;https://www.climate-policy-watcher.org/emission-factors/change-in-biomass-carbon-stocks-aboveground-biomass-and-belowground-biomass.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;climate-policy-watcher&lt;/a&gt; but I would like to understand a bit better.&lt;/p&gt;&#xA;&lt;p&gt;Is the idea of Equation 2.8 in that linked page, that one should first estimate properties of the existing forest and also the &amp;quot;Biomass Expansion Factor&amp;quot;, then one assumes that the existing forest will grow according to this factor? It seems from reading the related section on how to estimate the BCEFS, that it is always positive and related to growth of a tree.&lt;/p&gt;&#xA;&lt;p&gt;However I find that this leads to the conclusion that every forest just expands naturally, which seems pretty odd. Certainly if I compute the total existing forest cover and multiply it by some positive factor, I will come to the conclusion that the forest is expanding and absorbing carbon, but I'm pretty skeptical that this is accurate. Don't most forest just reach  steady state in general? Aren't there many non-anthropogenic factors which limit the growth of a forest, so that one cannot estimate the biomass growth of a forest just from the natural growth of a tree?&lt;/p&gt;&#xA;" OwnerUserId="27589" LastEditorUserId="2470" LastEditDate="2022-09-07T08:16:24.983" LastActivityDate="2022-09-07T08:16:24.983" Title="Forest Land Remaining Forest Land, Emissions Algorithm" Tags="|co2|emissions|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24294" PostTypeId="2" ParentId="24267" CreationDate="2022-09-07T12:47:58.600" Score="2" Body="&lt;p&gt;Good question (and welcome!)...&lt;/p&gt;&#xA;&lt;p&gt;I like the quantitative nature of the initial answer above (as  well as the &lt;em&gt;very good disclosure&lt;/em&gt; of &lt;strong&gt;isotropic and homogenous&lt;/strong&gt; subsurface nature that is technically never true in the so-called &amp;quot;real world&amp;quot;), but for my take, I'm going to forgo presenting any equations or numbers (although, embedded links herein will do that for me!).&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;Read all this paragraph and the links if you want more technical info&lt;/code&gt;: Let's parse out some things before presenting an answer below. Remember, that temperature (usually) increases with depth (think  of lithostatic pressure). Also, you say &amp;quot;pressure&amp;quot; but at this point, it's better (long term in school or professional life) to think of &lt;em&gt;that&lt;/em&gt; aspect of subsurface conditions as &lt;strong&gt;stress&lt;/strong&gt; (and how that affects &lt;strong&gt;strain&lt;/strong&gt; - see last sentence of this verbose paragraph). Also, even though you've only mentioned pressure, seismic velocities, and &lt;a href=&quot;https://www.researchgate.net/publication/248242596_Correlations_between_Poisson%27s_ratio_and_seismic_wave_velocities_for_some_common_rocks_and_sulfide_ores&quot; rel=&quot;nofollow noreferrer&quot;&gt;Poisson's ratio&lt;/a&gt;, it's critically important to keep in mind other so-called &amp;quot;elastic  parameters&amp;quot; such as Young's Modulus, Shear Modulus, and Bulk Modulus, and (arguably most important of all) &lt;a href=&quot;https://en.wikipedia.org/wiki/Lam%C3%A9_parameters&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lame parameters&lt;/a&gt;. Also, think of how these things change (or are absent) based on P- and S-wave velocities. Lastly, I implore you to do some investigation of what rheology means in regards to this topic.&lt;/p&gt;&#xA;&lt;p&gt;OK. So, what does &lt;a href=&quot;https://en.wikipedia.org/wiki/Poisson%27s_ratio&quot; rel=&quot;nofollow noreferrer&quot;&gt;Poisson's ratio&lt;/a&gt; basically describe? Well, it's estimating the &amp;quot;rigidity&amp;quot; of something (a rock or mineral, since we are taking about the subsurface!). What do I mean by &lt;em&gt;rigidity&lt;/em&gt;? It's something that is technically anything (some would argue with this) &lt;em&gt;but&lt;/em&gt; pure water (i.e. it has some form of elastic behavior).&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;To answer your question&lt;/strong&gt;: simply, think that that pressure affects temperature, which then affects the geology (which is the proxy here for Poisson's ratio). So, &amp;quot;hotter&amp;quot; and/or &amp;quot;viscous&amp;quot; less rigid material (think heated rubber) will facilitate &lt;strong&gt;slower&lt;/strong&gt; seismic velocities while &amp;quot;colder&amp;quot; and/or &amp;quot;solid&amp;quot; more rigid material (think cold steel) will result in &lt;strong&gt;higher&lt;/strong&gt; seismic velocities.&lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2022-09-07T12:47:58.600" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24295" PostTypeId="1" CreationDate="2022-09-07T13:53:20.083" Score="1" ViewCount="18" Body="&lt;p&gt;I have been trying to update the QSWAT+ crop database to include new crops. However it seems the model refuses to read a look-up table with new crops leaving me unable to represent all the various crops that I have in my study area. This is with regards to the first stage where HRU delineation is performed&lt;/p&gt;&#xA;&lt;p&gt;To work around this, I create the HRUs  using a look-up table with codes for crops accepted by SWAT+ and then later I create a record of my crop in the QSWAT+ editor under the plant database and link to the wrong record.&lt;/p&gt;&#xA;&lt;p&gt;I would like to know how to make QSWAT+ accept a look-up table (and a plant database) with new crops (as it does in SWAT2012) in the initial HRU delineation step.&lt;/p&gt;&#xA;" OwnerUserId="27593" LastActivityDate="2022-09-07T13:53:20.083" Title="Updating plant/crop database" Tags="|hydrology|models|water|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24296" PostTypeId="1" CreationDate="2022-09-07T18:05:08.837" Score="1" ViewCount="22" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/B907c.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/B907c.png&quot; alt=&quot;error image attached&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The following error about HRU occurred when I was trying to implement manual (advanced) irrigation operation.&lt;/p&gt;&#xA;&lt;p&gt;An additional message advises that I contact developers directly when you want to create an advanced irrigation schedule. I have done that but the responses take long. Is there anyone out there who has resolved the problem-please assist.&lt;/p&gt;&#xA;" OwnerUserId="27593" LastEditorUserId="27593" LastEditDate="2022-09-08T13:47:16.410" LastActivityDate="2022-09-08T13:47:16.410" Title="Developing or implementing manual/advanced irrigation in SWAT+" Tags="|hydrology|models|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24297" PostTypeId="1" CreationDate="2022-09-07T18:22:25.157" Score="1" ViewCount="576" Body="&lt;p&gt;&lt;em&gt;Is flooding an atmospheric or a geological hazard?&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;From my understanding you would define the above terms as:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Atmospheric hazards&lt;/strong&gt; - hazards that are caused or effect weather or climate. For example tornadoes and hurricanes.&#xA;&lt;strong&gt;Geological hazards&lt;/strong&gt; - hazards that are caused or effect land or tectonic plates. For example earthquakes and landslides.&lt;/p&gt;&#xA;&lt;p&gt;So what would you class flooding as? It seems to fit either or in some cases neither.&lt;/p&gt;&#xA;" OwnerUserId="27594" LastActivityDate="2022-09-07T18:22:25.157" Title="Is flooding an atmospheric or a geological hazard?" Tags="|natural-disasters|flooding|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="24298" PostTypeId="1" CreationDate="2022-09-08T14:03:42.793" Score="2" ViewCount="21" Body="&lt;p&gt;I am applying SWAT+ in an area with multiple reservoirs used for irrigation. I also have a lot of HRUs representing the various crop types in the catchment. The problem is that SWAT+ assigns one reservoir to irrigate a specific HRU &lt;strong&gt;type&lt;/strong&gt;. However, the reality is that I have same type HRUs (spread all over the catchment) that are irrigated from different reservoirs. I need to assign the correct reservoir per each HRU.&lt;/p&gt;&#xA;&lt;p&gt;I have attempted to manually create a management schedule for each HRU but this is tedious if one has hundreds of HRUs to irrigate from different reservoirs. Can anyone assist with a faster method to do this?&lt;/p&gt;&#xA;" OwnerUserId="27593" LastActivityDate="2022-10-04T18:05:52.913" Title="Irrigating from multiple reservoirs in SWAT+" Tags="|hydrology|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24300" PostTypeId="1" CreationDate="2022-09-08T20:06:12.947" Score="2" ViewCount="77" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/31Q6s.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/31Q6s.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I found this in the waters of the Dominican Republic -- any idea of what it belongs to/how old it might be? I thought it might be a tooth, but I tried matching to existing marine life in the area but could not find a definite match. Thanks for your help!&lt;/p&gt;&#xA;" OwnerUserId="27599" LastEditorUserId="6298" LastEditDate="2022-09-10T15:30:34.247" LastActivityDate="2022-09-10T15:30:34.247" Title="What kind of fossil or creature is this from? Found in the ocean" Tags="|geobiology|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24301" PostTypeId="1" CreationDate="2022-09-09T02:32:57.517" Score="1" ViewCount="13" Body="&lt;p&gt;In the descriptions of polar cells, it is usually described as cold and dense air sinks at poles. But I don't understand why air at high altitude is denser than low altitude at poles.&lt;/p&gt;&#xA;&lt;p&gt;The polar cells are described as thermally direct cells, directly influenced by the low temperature of surface. I don’t understand how the low surface temperature at poles is related to the (relatively) high density of air at high altitude.&lt;/p&gt;&#xA;&lt;p&gt;Wikipedia (&lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_circulation&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt;) says that the air transported from lower latitude (at high altitude) is considerably denser than the underlying air at poles, but I feel it is not explaining anything. In particular, I don't know how it is thermally direct.&lt;/p&gt;&#xA;" OwnerUserId="11086" LastEditorUserId="11086" LastEditDate="2022-09-09T02:46:33.300" LastActivityDate="2022-09-09T02:46:33.300" Title="Altitudinal gradient in air density at poles" Tags="|wind|pressure|air-currents|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24302" PostTypeId="2" ParentId="24300" CreationDate="2022-09-09T21:12:04.803" Score="1" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Hxmex.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Hxmex.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;Thanks for your help everyone--after your tips I did some sleuthing, and in the included picture/top right in black and white, that looks EXACTLY like what i found, the 'arm' of some kind of starfish.&lt;/p&gt;&#xA;" OwnerUserId="27599" LastActivityDate="2022-09-09T21:12:04.803" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24303" PostTypeId="2" ParentId="23890" CreationDate="2022-09-10T23:49:09.130" Score="1" Body="&lt;p&gt;The jet streams in our rotating (spheroid) planet meander because they cannot maintain a straight zonal course. The atmospheric flow is effectively perturbed upon collision to large mountain ranges like the Rockies and the Himalayas; an effect that is also felt at the jet stream level (i.e., around 10km above ground; upper-troposphere). The inhomogeneous temperature field due to land-sea contrasts and the latitude-dependent insolation results in an inhomogeneous pressure field that gives rise to winds of any direction and eddies. Convection, clouds and precipitation can also affect the upper-tropospheric flow.&lt;/p&gt;&#xA;&lt;p&gt;All these reasons can provide a &amp;quot;kick&amp;quot; in an initially zonal jet. This &amp;quot;kick&amp;quot; means that air masses will move toward different latitudes to the north and south maintaining the vorticity of their original position (since vorticity is conserved under certain assumptions). Cyclonic/anticyclonic rotational movement thus emerges and the jet develops the so-called Rossby waves. These waves are highly-dynamic flow features with a shape and propagation that evolve constantly and give rise to the meandering of the jet that hosts them. Since some regions in the midlatitudes are baroclinically highly unstable (i.e., the meridional temperature gradient is large and small eddies can quickly grow bigger), these meanders are often rather pronounced and the meridional component of the wind dominates the zonal one.&lt;/p&gt;&#xA;" OwnerUserId="21690" LastActivityDate="2022-09-10T23:49:09.130" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24304" PostTypeId="2" ParentId="22697" CreationDate="2022-09-11T02:03:08.153" Score="0" Body="&lt;p&gt;Perhaps due to Gaillard Cut/Culebra Cut (&lt;a href=&quot;https://en.wikipedia.org/wiki/Culebra_Cut&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Culebra_Cut&lt;/a&gt;). I presume this is probably an artificial reduction in height of the col.&lt;/p&gt;&#xA;" OwnerUserId="27566" LastActivityDate="2022-09-11T02:03:08.153" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24305" PostTypeId="1" CreationDate="2022-09-11T10:05:19.750" Score="1" ViewCount="36" Body="&lt;p&gt;I was looking through wikipedia a few weeks ago while half asleep, reading articles about rocks and their chemical compositions. I then came across a certain crystallographic notation which I had not seen before, encoding (if I remember correctly) the configuration of tetrahedral complexes in the crystal. There also were curly brackets involved. Sadly, I was already too out of it to remember the name, and subsequent wikipedia journeys revealed nothing. Did I dream this? If not, what is this notation?&lt;/p&gt;&#xA;" OwnerUserId="27610" LastActivityDate="2022-09-11T10:05:19.750" Title="Help me find a certain type of crystallographic notation" Tags="|geology|geochemistry|crystallography|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24306" PostTypeId="1" CreationDate="2022-09-11T14:19:44.997" Score="1" ViewCount="197" Body="&lt;p&gt;I understand that it is &lt;em&gt;possible&lt;/em&gt; for the coriolis effect and the pressure gradient force (PGF) to cancel each other out, but it appears to be a &lt;em&gt;tendency&lt;/em&gt; (rather than just a possibility). What is the mechanism behind this?&lt;/p&gt;&#xA;&lt;p&gt;I understand that as the wind is bent, the part/vector of the coriolis effect that acts in direct opposition of the PGF increases. But once the wind is bent so that it blows parallel to the isobars, why would the coriolis effect (have the tendency to) be similar to the PGF at that point?&lt;/p&gt;&#xA;&lt;p&gt;Is it because 1) the wind picks up speed as long as it moves down the gradient at angle less than 90°, and 2) an increase in wind speed increases the coriolis effect? So that there will always be a moment where the coriolis force has grown equal to the PGF (at which point the wind will stop speeding up, because it moves paralel to the isobars)?&lt;/p&gt;&#xA;" OwnerUserId="27611" LastEditorUserId="27611" LastEditDate="2022-09-11T15:52:52.230" LastActivityDate="2022-10-15T15:05:45.680" Title="In geostrophic wind, what is the mechanism behind the tendency of the coriolis effect/force and the pressure gradient force to balance each other out?" Tags="|meteorology|atmosphere|wind|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24307" PostTypeId="2" ParentId="1092" CreationDate="2022-09-11T21:03:03.477" Score="1" Body="&lt;p&gt;I needed hourly historical data for my zip code for heat pump comparison.  NOAA only had data for 2 cities in all of NY and neither were relevant.  I tried to use one of them anyway and also found lots of -9999 temps in each year for which i assume is when there were outages.  Also, the reports were in a horribly unusable format with space-aligned columns rather than using something more easily consumable like CSV.&lt;/p&gt;&#xA;&lt;p&gt;I later found &lt;a href=&quot;https://www.visualcrossing.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.visualcrossing.com/&lt;/a&gt;.  This one let you build a query and choose which data points you want on your report as well as if you want json or csv format for your output.  I didn't find any missing data points when i got 10 years worth of data for my zip.  It wasn't free, but it was incredibly reasonable at only about 87 cents per year.  It was definitely worth a dollar to not have to mess with cleaning up the data from noaa.&lt;/p&gt;&#xA;" OwnerUserId="27613" LastActivityDate="2022-09-11T21:03:03.477" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24311" PostTypeId="1" CreationDate="2022-09-12T18:51:02.670" Score="2" ViewCount="29" Body="&lt;p&gt;I'm going to use RS/GIS techniques and an Analytic Hierarchy Process (AHP)  to identify potential groundwater zones , but first I need to identify all factors influencing the existence of groundwater. So far I have these layers, Rainfall, slope, lineament density, drainage density, lulc, geology, soil, topographic wetness index. I want to know what else can influence the existence of groundwater?&lt;/p&gt;&#xA;" OwnerUserId="27621" LastEditorUserId="21672" LastEditDate="2022-09-13T08:23:38.803" LastActivityDate="2022-09-13T08:23:38.803" Title="Factors influencing existence of groundwater" Tags="|hydrology|groundwater|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24312" PostTypeId="1" AcceptedAnswerId="24313" CreationDate="2022-09-13T14:23:51.517" Score="3" ViewCount="589" Body="&lt;p&gt;The specific humidity of ERA5 data is kg/kg, but some articles work with this variable in g/kg.&#xA;How can I convert this?&lt;/p&gt;&#xA;&lt;p&gt;Or to compare with precipitation, evaporation, and other variables, how to convert to mm/day?&lt;/p&gt;&#xA;&lt;p&gt;It is possible?&lt;/p&gt;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;" OwnerUserId="27625" LastEditorUserId="27625" LastEditDate="2022-09-13T14:26:21.747" LastActivityDate="2022-09-13T14:43:55.183" Title="How to convert specific humidity ERA5 in kg/kg to g/kg or mm/day?" Tags="|meteorology|humidity|data-formats|era|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24313" PostTypeId="2" ParentId="24312" CreationDate="2022-09-13T14:43:55.183" Score="5" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;The specific humidity of ERA5 data is kg/kg, but some articles work with this variable in g/kg. How can I convert this?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Conversion from kg/kg to g/kg is as simple as multiplying by 1000.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Or to compare with precipitation, evaporation, and other variables, how to convert to mm/day?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I would say that this conversion is not possible because the units are not &amp;quot;equivalent&amp;quot;.  Relative humidity is a description of the &lt;em&gt;content&lt;/em&gt; of moisture in the air whereas &lt;code&gt;mm/day&lt;/code&gt; is a &lt;em&gt;rate&lt;/em&gt;, which has a temporal component.&lt;/p&gt;&#xA;&lt;p&gt;Consider using the UDUNITS package, which has various implementations in python and R:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://ncas-cms.github.io/cfunits/&quot; rel=&quot;noreferrer&quot;&gt;cfunits&lt;/a&gt; (python)&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://cran.r-project.org/web/packages/udunits2/index.html&quot; rel=&quot;noreferrer&quot;&gt;udunits2&lt;/a&gt; (R)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="14348" LastActivityDate="2022-09-13T14:43:55.183" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24315" PostTypeId="1" CreationDate="2022-09-14T07:52:27.283" Score="0" ViewCount="43" Body="&lt;p&gt;Hi I need a map for the North American region that shows the change in rainfall intensity. Unfortunately, I can only find maps like this &lt;a href=&quot;https://earthobservatory.nasa.gov/features/Water/page3.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;map&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Unfortunately, these are not detailed to use.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2022-09-14T08:17:30.013" LastActivityDate="2022-09-14T08:17:30.013" Title="Map showing the change in precipitation intensity" Tags="|models|rainfall|mapping|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24317" PostTypeId="2" ParentId="21136" CreationDate="2022-09-14T11:32:41.543" Score="1" Body="&lt;p&gt;I think that global warming will have no winners. The climate has already changed, and we can see the consequences. There are a lot of people who still deny that fact, but it happens. Some countries suffer from droughts, fires, and floods. From one side, it may be because of the geographical location, but it happens so often lately, and it's so widespread, so it's not only location.&lt;/p&gt;&#xA;&lt;p&gt;The rise of temperature will be different in parts of the planet; some people will feel it more, some less. The same with temperature impact on flora, fauna, etc.&lt;/p&gt;&#xA;&lt;p&gt;I don't want to write a lot, but we have to remember that we live on one planet. Everything is connected, even if it's not obvious. Global warming may affect one part of the world, a few countries, but those countries are connected to another. And these another to another.&lt;/p&gt;&#xA;&lt;p&gt;Yesterday I finished a small paper on that theme and did a research. I read different information, research, articles, and paper examples on &lt;a href=&quot;https://paperap.com/free-papers/global-warming/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://paperap.com/free-papers/global-warming/&lt;/a&gt;, and all that info I found proved to me once again that global warming is a danger. And people may think differently, but I'm writing what I think about all that.&lt;/p&gt;&#xA;&lt;p&gt;No one will win, it's a fact.&lt;/p&gt;&#xA;" OwnerUserId="27630" LastEditorUserId="27630" LastEditDate="2022-09-16T16:51:47.480" LastActivityDate="2022-09-16T16:51:47.480" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24318" PostTypeId="1" CreationDate="2022-09-14T15:34:25.740" Score="1" ViewCount="49" Body="&lt;p&gt;Old MacDonald had a farm. And on that farm, he had a pond. Old MacDonald (OMD) liked&#xA;spending a lot of time fishing in his pond. One day a friend told him that the fish will grow twice as big if the pond was twice as large. So, OMD decided to enlarge his pond from 2.5 acres to 5.0 acres. Because he spent most of his time fishing and not studying the hydrologic equation, something strange happened. Can you tell? Here are some numbers to crunch:&lt;/p&gt;&#xA;&lt;p&gt;Qin = 130.8 cubic yards per hour&lt;/p&gt;&#xA;&lt;p&gt;Qout = 97 m³/hr&lt;/p&gt;&#xA;&lt;p&gt;Qseep = 0.0055 L/minute per m² of the lake area&lt;/p&gt;&#xA;&lt;p&gt;P (precipitation) = 45 inches per year per m² of lake area (Account only for P falling directly&#xA;on the lake)&lt;/p&gt;&#xA;&lt;p&gt;E (Evaporation) = 30 inches per year per m² of lake area (Account only for E directly from&#xA;the lake)&lt;/p&gt;&#xA;&lt;p&gt;I (Irrigation) = 88 ft per day&lt;/p&gt;&#xA;&lt;p&gt;h = 3 m (Assume that the lake describes a perfect circle).&lt;/p&gt;&#xA;&lt;p&gt;Tasks/Questions:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Scientists prefer SI units over the foot/inches/acres so commonly used in the U.S.&#xA;Please convert all non SI units into metric units (Hint: use meter and day units; convert&#xA;initial numbers accordingly)&lt;/li&gt;&#xA;&lt;li&gt;What is the volume of the lake before and after OMD started digging?&lt;/li&gt;&#xA;&lt;li&gt;Calculate the inflow and outflow from the lake before OMD enlarged it.&lt;/li&gt;&#xA;&lt;li&gt;Calculate the inflow and outflow after the lake was enlarged.&lt;/li&gt;&#xA;&lt;li&gt;Assume that before enlarging the lake, OMD diverted all inflows (including the amount of&#xA;rain falling onto the lake), how long would it take for the lake to drain completely?&lt;/li&gt;&#xA;&lt;li&gt;After OMD drained the lake and enlarged it, what happened to his lake?&lt;/li&gt;&#xA;&lt;li&gt;How could he have avoided this outcome?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="27633" LastActivityDate="2022-09-14T15:34:25.740" Title="Hydrologic Mass Balance" Tags="|hydrology|water|lakes|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24319" PostTypeId="1" AcceptedAnswerId="24323" CreationDate="2022-09-14T20:42:40.593" Score="1" ViewCount="103" Body="&lt;p&gt;How do melting glaciers dry rivers? Unless there's less precipitation during winter, I don't see how it affects the volume of water of the rivers that glaciers feed into. If it's cold, water accumulates as snow, and then during spring it melts and flows into rivers. If it's warm, it just rains and flows into rivers right away. What's the difference?&lt;/p&gt;&#xA;" OwnerUserId="22632" LastEditorUserId="22632" LastEditDate="2022-09-15T09:46:09.773" LastActivityDate="2022-09-15T09:46:09.773" Title="How do melting glaciers dry rivers?" Tags="|climate-change|water|glaciology|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24321" PostTypeId="1" AcceptedAnswerId="24336" CreationDate="2022-09-14T21:32:06.673" Score="2" ViewCount="78" Body="&lt;p&gt;How does dredging help the rivers that have gone dry? If you dig deeper, that small, and fixed, amount of water is just going to go lower, isn't it? That just what my layman's logic says, at least. And if it doesn't address the problem, which is not enough water, then why do they do it (or at least, &lt;a href=&quot;https://www.dw.com/en/rhines-low-water-levels-hit-german-shipping-minister-touts-dredging/a-62740312&quot; rel=&quot;nofollow noreferrer&quot;&gt;plan&lt;/a&gt; to, for example, in Germany)?&lt;/p&gt;&#xA;" OwnerUserId="22632" LastEditorUserId="22632" LastEditDate="2022-09-15T01:41:00.640" LastActivityDate="2022-09-18T07:51:42.217" Title="How does dredging help the rivers that have gone dry?" Tags="|climate-change|hydrology|rivers|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24322" PostTypeId="2" ParentId="12077" CreationDate="2022-09-14T22:07:18.667" Score="0" Body="&lt;p&gt;The mass of the atmosphere is equivalent to about 10 meters of water covering the entire planet.&lt;/p&gt;&#xA;&lt;p&gt;volume of ocean / earth surface area = 2.6 km&lt;/p&gt;&#xA;&lt;p&gt;volume of continental crust / earth surface area = 13.7 km&lt;/p&gt;&#xA;" OwnerUserId="6615" LastEditorUserId="6615" LastEditDate="2022-09-14T22:15:16.373" LastActivityDate="2022-09-14T22:15:16.373" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24323" PostTypeId="2" ParentId="24319" CreationDate="2022-09-15T08:31:22.850" Score="3" Body="&lt;p&gt;In monsoonal or highly seasonal climates, with precipitation concentrated into a few months of the year, dry season river flow is sustained by melting ice from previous years. If precipitation remains constant, but temperatures rise, more water will runoff in the rainy season, exacerbating flood risks, and there will be less ice to melt and provide dry season flows. In the period of transition from 'cold' to 'warm', total runoff may actually increase initially, as melt water component is added to rainfall.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2022-09-15T08:31:22.850" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24324" PostTypeId="2" ParentId="24306" CreationDate="2022-09-15T10:11:27.927" Score="1" Body="&lt;p&gt;Page 556 of &amp;quot;Earth Science&amp;quot; by Tarbuck &amp;amp; Lutgens (2015) says the following:&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&amp;quot;The only force acting on a stationary parcel of air is the pressure gradient force. Once the air begins to accelerate, the Coriolis effect deflects it to the right in the Northern Hemisphere. Greater wind speeds result in a stronger Coriolis effect (deflection) until the flow is parallel to the isobars. At this point, the pressure gradient force and Coriolis effect are in balance, and the flow is called a geostrophic wind.&amp;quot;&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="27611" LastActivityDate="2022-09-15T10:11:27.927" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24325" PostTypeId="1" CreationDate="2022-09-15T13:07:48.893" Score="1" ViewCount="27" Body="&lt;p&gt;How can seismologists estimate velocity (on the different layers) of the wave propogated through the earth , only from given seismic trace(s) ?&lt;/p&gt;&#xA;" OwnerUserId="27481" LastActivityDate="2022-09-15T13:07:48.893" Title="Estimation of velocity of the wave from seismic trace" Tags="|seismology|seismic|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24326" PostTypeId="1" CreationDate="2022-09-15T13:17:23.163" Score="2" ViewCount="37" Body="&lt;p&gt;I'm researching various paleo-events (climate, geomorphology, etc) from different articles. I would in turn like to collate the findings into one comprehensive timeline.&lt;/p&gt;&#xA;&lt;p&gt;Example:&#xA;I have articles dealing with specific events happening in specific years (ex. 7989 B.P.), seasons in years (ex. winter 7989 B.P.), and year ranges (ex. 8100 - 7800 B.P.). The events are (a) changes in SST, SSS, precipitation, humidity, RSL; or (b) changes in geomorphology as a result of SL change or tectonics. The events also happen (1) locally, (2) regionally, or (3) globally (ex, the local pollen record changes due to changes in regional paleoclimate, which in turn are interconnected to global paleoclimatic changes.)&lt;/p&gt;&#xA;&lt;p&gt;So various articles discuss the local, regional, and global changes using the different proxies. And I would like to create my own timeline and keep track of all these changes.&#xA;And I would like this timeline to include year ranges, specific years, and seasons within a year. Coupled to this, I want to be able to see what is happening in the proxy record, the paleoenvironment, and the citation of my sources. In essence, it's a database.&lt;/p&gt;&#xA;&lt;p&gt;But I'm not familiar with creating my own database. Excel is getting too convoluted. I've resorted to putting sticky notes on my window and shuffling them around as I add new events.&lt;/p&gt;&#xA;&lt;p&gt;Is there a program for this? (I'm familiar with Tilia and PAST, but those require raw data...and I just want to collate the different papers).&lt;/p&gt;&#xA;&lt;p&gt;Thank you and apologies for such long text.&lt;/p&gt;&#xA;" OwnerUserId="27637" LastActivityDate="2022-09-15T13:17:23.163" Title="Create my own timeline by collating data from different research" Tags="|geomorphology|paleoclimate|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24327" PostTypeId="2" ParentId="24306" CreationDate="2022-09-15T13:45:09.463" Score="2" Body="&lt;p&gt;Yes it is because of that:&lt;/p&gt;&#xA;&lt;p&gt;1 - The wind must pick up speed as long its angle is less than 90° to the pressure gradient.  This is because it has a net force in its direction of motion, and &lt;span class=&quot;math-container&quot;&gt;$F=ma$&lt;/span&gt;, so it has acceleration towards the low pressure.  Whereas Coriolis &amp;quot;force&amp;quot; being always 90° from movement means it cannot accelerate/affect the magnitude, only change the direction.&lt;/p&gt;&#xA;&lt;p&gt;2 - And Coriolis is &lt;span class=&quot;math-container&quot;&gt;$f\times v$&lt;/span&gt;, meaning Coriolis Force indeed increases as velocity increases.&lt;/p&gt;&#xA;&lt;p&gt;As the process continues, the change in direction means less and less of the PGF is a component that changes the magnitude of velocity, and more and more of it is normal to motion... and so opposing the Coriolis.&lt;/p&gt;&#xA;&lt;p&gt;If they didn't cancel each other out when the parcel reached 90° to the PGF, then the parcel would still have a directional acceleration... meaning it then again becomes not 90° to the PGF.&lt;br /&gt;&#xA;If PGF were stronger/it is less than 90° to PGF, it would further accelerate in velocity, and so thus further increase Coriolis... and be directed back to perpendicular.&#xA;If Coriolis were somehow stronger/it somehow got beyond 90°, the PGF would then start to have a component that decelerates the velocity.  Which would decrease the Coriolis counteracting it, and so pull it back (left in the NH) towards perpendicular.&lt;/p&gt;&#xA;&lt;p&gt;So the situation is entirely restorative/stable.  It can only be at balance when they cancel each other out, and the motion is at that 90° angle (unless there are additional forces).  When it somehow isn't in that balanced situation, the forces work to accelerate/push it back towards that situation.&lt;/p&gt;&#xA;&lt;p&gt;With a &amp;quot;sudden&amp;quot; low pressure, nearby parcels would not have the time/distance to undergo this process and accelerate/change direction enough before reaching the low.    But typically atmospheric pressure changes are gradual changes, so basically the change in motion are so gradual that the motion at any time is essentially geostrophic at any moment.&lt;/p&gt;&#xA;&lt;p&gt;Rapid pressure changes can and do still lead to local ageostrphic motion, where the change is of such speed and magnitude that the Coriolis Force hasn't responded yet and so there is a more meaningful component of motion out of balance (and so the motion is more non-perpendicular to the PGF).&lt;/p&gt;&#xA;&lt;p&gt;And other forces... in particular friction at lower levels of the atmosphere... do alter the balance.  Friction continually decelerating motion leads to a result where the path is consistently a bit less than 90°, towards the low pressure, which leads (apart from other factors) to filling of the low pressure over time.  Particularly strong persistent low pressure can also result in a flow nearby that must turn so rapidly that there is a significant centrifugal &amp;quot;force&amp;quot; as well... this extra force isn't degenerative like friction is, but leads to a different balance instead, the &lt;a href=&quot;https://www.theweatherprediction.com/habyhints3/743/#:%7E:text=The%20gradient%20wind%20is%20a,centrifugal%20(outward%20fleeing)%20force.&quot; rel=&quot;nofollow noreferrer&quot;&gt;gradient wind balance&lt;/a&gt;, with a somewhat lower velocity compared to geostrophic balance.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2022-09-15T14:08:19.007" LastActivityDate="2022-09-15T14:08:19.007" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24329" PostTypeId="1" CreationDate="2022-09-15T20:54:27.840" Score="3" ViewCount="75" Body="&lt;p&gt;The Stack Exchange question wondering &lt;a href=&quot;https://earthscience.stackexchange.com/questions/19849/how-much-of-the-petroleum-ever-formed-has-made-it-into-reservoir-rocks&quot;&gt;how much of the petroleum ever formed made it into reservoir rocks&lt;/a&gt; got me pondering what becomes of the organic material that isn't trapped in reservoir rock.&lt;/p&gt;&#xA;&lt;p&gt;I imagine it continues downward and potentially stays/becomes more diffuse than is found in reservoir rock.  But (understanding that less is probably known about the intimate details for deeper in the Earth)... what are the theories on where and how it would wind up?&lt;/p&gt;&#xA;&lt;p&gt;Would there be a layer it would tend to collect at due to stratification/gravity?  Would the bulk of it wind up in different compounds due to potentially much longer time (conceivably long into the future), different rock compositions, and different pressures/temperatures?  Or would it just gradually spread throughout the mantle into minute concentrations?&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2022-09-19T21:52:27.743" Title="What would eventually happen to untrapped petroleum?" Tags="|geology|petroleum|biomineralization|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24330" PostTypeId="2" ParentId="24137" CreationDate="2022-09-16T11:20:43.377" Score="1" Body="&lt;p&gt;My question was naïve to the weather dynamics —so the answer is &lt;em&gt;technical&lt;/em&gt;: the heat is on the ground, not in the stratosphere.&lt;/p&gt;&#xA;&lt;p&gt;So there are two things, infrared deflection into space and radiative cooling, wherein heat gets emitted as infrared radiation into space —the two blend into each other, but stratospheric clouds primarily do the former.&#xA;Given that the hot weather system originated from the south (Sahara) it would be mostly pointless deflecting incoming IR rays, which are not causing the heat in that precise spot. The heat was also on the ground not in the atmosphere, so irradiative cooling up high would be ineffective. After all, on cloudy days during the heatwaves, the temperatures were still well above average during both the daytime and &lt;em&gt;nightime&lt;/em&gt;. The nightime detail is because the heat irradiated by the ground via irradiative cooling was being deflected back by the (tropospheric) cloud cover, so in effect an IR mirror is a bad thing as the heat was from the sub but not from there.&#xA;Similarly, it has recently been proposed that the norther polar vortex (a continuous cyclone that traps the cold in the artic) could be stabilised via stratospheric aerosol injection. Controversies apart, the aim would be to deflect incoming rays, not irradiate stratospheric heat.&lt;/p&gt;&#xA;&lt;p&gt;There are ground-based technologies that employ radiative cooling (ranging from TiO2 white paint to theoretical nanoengineered panels from IEEE papers). Being more targetted they can be used to tackle the &amp;quot;urban heat island effect&amp;quot; wherein parts of a developed areas can be several degrees higher. So these would be a better safeguard against extreme heatwaves assuming we are unable to rapidly remove 950 gigatons of carbon dioxide by growing new biomass or sequestering it underground.&lt;/p&gt;&#xA;" OwnerUserId="18400" LastActivityDate="2022-09-16T11:20:43.377" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24331" PostTypeId="1" AcceptedAnswerId="24332" CreationDate="2022-09-17T04:08:09.290" Score="2" ViewCount="128" Body="&lt;p&gt;I think I have heard that if the carbon emission raises a small amount above the current, it would be &amp;quot;point of no return&amp;quot;. I heard it a long time ago, so I just searched Google and the top article says &amp;quot;irreversible damage&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;But when I searched Google for a graph of historic CO&lt;sub&gt;2&lt;/sub&gt; levels, there was something like the one below. Granted that this was not the top search result (the top one was not continuous), but if this graph is correct, the CO&lt;sub&gt;2&lt;/sub&gt; level has been historically much higher than now. If there is any irreversible damage, won't that have already happened? And the CO&lt;sub&gt;2&lt;/sub&gt; level seems to be able to go down once it has risen, so it does not seem that the current CO&lt;sub&gt;2&lt;/sub&gt; level cannot get lowered once a certain level is reached.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BLYzF.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BLYzF.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27645" LastEditorUserId="2470" LastEditDate="2022-09-17T07:50:49.703" LastActivityDate="2022-09-17T18:44:21.333" Title="What exactly does point-of-no-return for carbon emissions mean?" Tags="|climate-change|carbon-cycle|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24332" PostTypeId="2" ParentId="24331" CreationDate="2022-09-17T18:44:21.333" Score="3" Body="&lt;p&gt;Its a question of time scales.  Yes, carbon concentrations have been higher in the past.  We've also had planetary extinction events that have wiped out a significant portion of the earth's biota.&lt;/p&gt;&#xA;&lt;p&gt;The 'point of no return' speaks to the idea that, before that point, we are able to return to a pre-anthropogenic climate which we are familiar with and is able to continue to support us (through agriculture, predictable drought &amp;amp; flood recurrance).&lt;/p&gt;&#xA;&lt;p&gt;Conversely, once we pass that point, there are feedback loops that will cause the climate to move towards a new 'stable' state which we are unfamiliar with and may not support many of the things that have made our lives easy.&lt;/p&gt;&#xA;&lt;p&gt;That's not to say &amp;quot;the earth&amp;quot; will be irreperably damaged, but rather that the time scales involved are not practical, and we will have to deal with some problematic climate change effects.&lt;/p&gt;&#xA;" OwnerUserId="14348" LastActivityDate="2022-09-17T18:44:21.333" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24333" PostTypeId="1" CreationDate="2022-09-18T00:34:50.593" Score="1" ViewCount="25" Body="&lt;p&gt;Found at shore off Genoa, Italy.  My kids really think it’s a molar of some kind.. &lt;a href=&quot;https://i.stack.imgur.com/EoLcZ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EoLcZ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27648" LastActivityDate="2022-09-18T00:34:50.593" Title="Could this be a tooth or a fossil, looks like a molar" Tags="|oceanography|fossils|" AnswerCount="0" CommentCount="2" ClosedDate="2022-09-18T15:30:53.837" ContentLicense="CC BY-SA 4.0" />
  <row Id="24335" PostTypeId="2" ParentId="21136" CreationDate="2022-09-18T07:44:53.650" Score="0" Body="&lt;p&gt;Dictators and military companies would have a bonanza because today, climate and social instability is exploited to fund billion dollar military campaigns... If rivers dry out even more, the migrations, resource battles, popular discontent, will mean more wars.&lt;/p&gt;&#xA;&lt;p&gt;Farmers in some regions will have better crops from more CO2 and warmth, i.e. some Russia regions.&lt;/p&gt;&#xA;&lt;p&gt;Green energy companies... solar/wind/eco companies will become popular if the rivers have fish floating in them from hot water, and the trees go yellow in july, like it happened everywhere in France in 2022.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastActivityDate="2022-09-18T07:44:53.650" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24336" PostTypeId="2" ParentId="24321" CreationDate="2022-09-18T07:51:42.217" Score="2" Body="&lt;p&gt;Actually, it's about access to the water table. If the water table is under the river, it can be accessed by dredging. Either way, it's just a last resort for totally anomalous weather.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastActivityDate="2022-09-18T07:51:42.217" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24337" PostTypeId="1" CreationDate="2022-09-19T18:07:27.403" Score="3" ViewCount="39" Body="&lt;p&gt;The Vredefort Crater is said to have been 40km deep and 100km wide. But what I'm curious about, is how long it retained that shape. Would magma have immediately leaked into it and filled it, for example? Is it likely the soil and rock around it collapsed into the hole? Or would it be something that took years or huge timescales to erode and fill?&lt;/p&gt;&#xA;&lt;p&gt;It'd be really neat if it lasted to today, so you could descend into its incredible depths and admire its vastness.&lt;/p&gt;&#xA;" OwnerUserId="27657" LastActivityDate="2022-09-19T18:07:27.403" Title="Did the Vredefort Crater fill in soon after impact?" Tags="|earth-history|meteorite|erosion|impact-craters|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24339" PostTypeId="2" ParentId="20757" CreationDate="2022-09-19T21:02:21.053" Score="-3" Body="&lt;p&gt;Increasing the CO2 concentration can not cause global warming.  CO2 can only absorb Earth's IR radiation in specific wavelengths, (like color filters in visible light) specifically 14-16 microns.  NASA satellite data now available shows that the atmosphere in 1991 already had enough CO2 to absorb 100% of the radiation in these wavelengths.&#xA;So more CO2 could not aborb more, since there is no more.&#xA;The &amp;quot;green energy&amp;quot; war on fossil fuels is thus totally without any basis in fact.&#xA;The NASA data is stored at &amp;quot;NASA Technical Memorandum 103957, Appendices E and F&amp;quot;.&#xA;It now can be found on Amazon as a book.&lt;/p&gt;&#xA;" OwnerUserId="27659" LastActivityDate="2022-09-19T21:02:21.053" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24341" PostTypeId="2" ParentId="24329" CreationDate="2022-09-19T21:52:27.743" Score="2" Body="&lt;p&gt;Oil originally trapped in an oil reservoir, can, over millions of years, migrate laterally from one location to another, sometimes many tens of kilometers from the original reservoir.  We may think of present-day reservoirs as static and unchanging, but even now processes forcing the migration of the oil are continuing.  Oil and petroleum products can escape through horizontal and vertical fractures and fissures and ultimately discharge at the surface as vapors and liquids.  Vapors most easily penetrate such fractures and as they escape, they leave a residue by product of concentrated oil or tar.  This concentrated by product may be too viscous to migrate and will largely remain stationary.  If the residue is not highly viscous, the product may migrate with facility along fractures and also be discharged at the surface.  Most oil discharged to the surface becomes evapoconcentrated as volatile components escape into the atmosphere.  This thickened oil is tar, the most famous occurrence being the La Brea tar pits, in Los Angeles.&lt;/p&gt;&#xA;&lt;p&gt;Oil products can also become concentrated and solidify as an asphalt, called asphaltite or gilsonite. This product can be exposed at the surface and has an appearance like coal.  Upon closer examination, however, asphaltite may appear as a soft, light density, glassy material, that spalls with concoidal fractures like obsidian.  Gilsonite will burn, and can be refined into heavy oil and other useful petroleum products. The refining process, however, is noted for flaring methane as a by-product of the refining process.   Gilsonite is typically found in oil shale.&lt;/p&gt;&#xA;&lt;p&gt;Keep in mind that in many instances, oil at depth may be within a reservoir that is very hot.  The high temperature is due primarily to the geothermal gradient.  This heat can cause the volatilization of oil thereby driving the volatile products through fissures and along faults to escape at the surface.  The now thickened oil can also force open these same fissures and planes along faults and be deposited there.  In the case of gilsonite, the thickened petroleum can form sills between bedding planes as well as dikes along fissures and faults.  Erosion can later expose these deposits at the land surface.&lt;/p&gt;&#xA;" OwnerUserId="27660" LastActivityDate="2022-09-19T21:52:27.743" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24342" PostTypeId="1" CreationDate="2022-09-20T01:00:07.550" Score="1" ViewCount="90" Body="&lt;p&gt;Earth's atmosphere is especially good at refracting blue light, which makes the sky blue.&lt;/p&gt;&#xA;&lt;p&gt;Which gas or gasses is/are responsible for this?&lt;/p&gt;&#xA;&lt;p&gt;If some gasses in the atmosphere do not refract blue light, what colors DO they refract?&lt;/p&gt;&#xA;&lt;p&gt;Is it possible to have a breathable atmosphere with a non-blue sky?&lt;/p&gt;&#xA;" OwnerUserId="11842" LastActivityDate="2022-09-20T01:00:07.550" Title="Which chemicals are most responsible for the blue sky?" Tags="|atmosphere|atmospheric-optics|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24343" PostTypeId="1" CreationDate="2022-09-20T20:34:10.173" Score="1" ViewCount="33" Body="&lt;p&gt;Could it be feasible to have a tunnel using gravity to move water underground into central California, where a nuclear power plant can use the water to create electricity and desalinate it at the same time?&lt;/p&gt;&#xA;" OwnerUserId="27666" LastEditorUserId="6467" LastEditDate="2022-09-21T13:30:34.180" LastActivityDate="2022-09-21T13:30:34.180" Title="Desalination of Pacific Ocean water for California" Tags="|water|geoengineering|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24344" PostTypeId="1" CreationDate="2022-09-20T22:39:48.023" Score="2" ViewCount="130" Body="&lt;p&gt;The Gulf Stream is said to be&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Largely driven by wind stress, and&lt;/li&gt;&#xA;&lt;li&gt;Up to 1000 m deep.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;At the same time, I am reading that&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;the effect of the wind usually does not reach deeper than 100 m&lt;/li&gt;&#xA;&lt;li&gt;in Ekman motion theory water at a depth of 100 m will flow in the direction opposite to the surface current.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;How do these things fit together?&lt;/p&gt;&#xA;" OwnerUserId="27611" LastEditorUserId="27611" LastEditDate="2022-09-20T23:39:08.583" LastActivityDate="2024-02-13T18:05:45.800" Title="Gulf stream depth and Ekman's theory" Tags="|oceanography|ocean-currents|ocean-models|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24345" PostTypeId="1" CreationDate="2022-09-21T08:49:26.287" Score="0" ViewCount="129" Body="&lt;p&gt;I need to convert organic carbon provided in kg C/m2 to percent.&#xA;Any help would be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="15696" LastEditorUserId="6467" LastEditDate="2022-09-21T13:29:26.213" LastActivityDate="2022-09-23T08:30:07.627" Title="How to convert Carbon stored in surface sediments (kg/m2) to percent?" Tags="|sedimentology|carbon|biogeochemistry|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24346" PostTypeId="2" ParentId="24344" CreationDate="2022-09-21T15:15:25.333" Score="0" Body="&lt;p&gt;The winds over the north Atlantic are, basically, cyclonic: the southern winds blow westward and the northern winds blow eastward. Due to Eckman pumping, this creates a dome of water, and consequent higher pressure, in the Sargasso Sea. This, in turns, mandates a cyclonic flow of water around the higher-pressure dome with westward compression/intensification of the flow due to a latitude-dependent Coriolis effect.&lt;/p&gt;&#xA;" OwnerUserId="30" LastActivityDate="2022-09-21T15:15:25.333" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24347" PostTypeId="1" AcceptedAnswerId="24360" CreationDate="2022-09-21T18:59:09.473" Score="3" ViewCount="230" Body="&lt;p&gt;What kinds of differences from our Earth would we see with a moon in a geostationary orbit over the equator? Assuming the gravitational pull is roughly the same as it is with ours (my back of the napkin math says this moon would have to be one order of magnitude smaller to provide the same pull at its new height), what effects would this have on this new earth?&lt;/p&gt;&#xA;" OwnerUserId="27668" LastActivityDate="2022-09-25T09:51:11.920" Title="What would be the effect of a geostationary moon?" Tags="|tides|moon|earth-moon|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24348" PostTypeId="2" ParentId="24345" CreationDate="2022-09-22T08:44:27.383" Score="2" Body="&lt;p&gt;To answer your question requires some assumptions. Firstly in what is meant by kg Carbon/m2? m2 is a measure of area, not volume. So you might quote carbon deposition in kg/m2/year - and that wouldn't meaningfully translate as a percentage. Or you need information on the depth of the soil that will hold the carbon. There are &lt;a href=&quot;https://databasin.org/datasets/a4cb6d367eae4e52a08902874f8bfedf/&quot; rel=&quot;nofollow noreferrer&quot;&gt;global maps&lt;/a&gt; that use kg Carbon/m2 as a unit, with an assumption that it is in the top metre. So 7 kg Carbon/m2 would be equivalent to 7 kg Carbon/m3.  To convert that to a percentage you need information on the density of soils. Typical densities are 1.1 to 1.6 g/cm2, so assuming a density of 1.35 g/cm2 our 7 kg Carbon/m3 would be 0.7% Carbon. The calculation is complicated by the fact that actual soil density varies with moisture content and with organic matter - high Carbon soils are likely to have lower bulk densities, and so you shouldn't really use one density value for calculating a conversion.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastEditorUserId="21672" LastEditDate="2022-09-23T08:30:07.627" LastActivityDate="2022-09-23T08:30:07.627" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24352" PostTypeId="1" CreationDate="2022-09-23T01:31:20.860" Score="6" ViewCount="437" Body="&lt;p&gt;An intriguing question in Space SE &lt;a href=&quot;https://space.stackexchange.com/q/60417/12102&quot;&gt;Optimal depth for underground flyby?&lt;/a&gt; asks about a theoretical spacecraft trajectory for a &amp;quot;slingshot maneuver&amp;quot; also known as a &lt;a href=&quot;https://en.wikipedia.org/wiki/Gravity_assist&quot; rel=&quot;noreferrer&quot;&gt;gravitational assist&lt;/a&gt; or &amp;quot;flyby&amp;quot; with the relaxed condition that the trajectory can go through the earth (presumably through a carefully constructed tunnel who's path is adjusted to account for Earth's rotation during the f̶l̶y̶b̶y̶ &amp;quot;flythrough&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;There are answers there but currently the most rigorous numerical trajectories still assume a uniform density sphere. The answer will be much different if it can include the dramatic &lt;em&gt;factor of 5&lt;/em&gt; radial variation of Earth's density from say 2.5 (ignoring water) to over 13 g/cm&lt;sup&gt;3&lt;/sup&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I found the plot below in Wikimedia which certainly looks like it's piecewise polynomial and perhaps even piecewise parabolic.&lt;/p&gt;&#xA;&lt;p&gt;Sadly, it references only &lt;a href=&quot;https://www.gps.caltech.edu/uploads/File/People/dla/DLApepi81.pdf&quot; rel=&quot;noreferrer&quot;&gt;https://www.gps.caltech.edu/uploads/File/People/dla/DLApepi81.pdf&lt;/a&gt; as the source of the data and that link is of course broken (ones like this usually do) rather than a proper citation (name, year, journal, page number) or a doi link.&lt;/p&gt;&#xA;&lt;p&gt;So I'd like to ask the following.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Is there an approximate, piecewise continuous analytical model for Earth's radial density profile useful for numerical integration that can be used as a properly cite-able source for a Stack Exchange answer?&lt;/p&gt;&#xA;&lt;p&gt;One could reverse-engineer this one, but it would be better to get at the source.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/35yyl.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/35yyl.jpg&quot; alt=&quot;Earth's radial density distribution according to the Preliminary Reference Earth Model (PREM). 29 December 2010&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Earth's radial density distribution according to the Preliminary Reference Earth Model (PREM). 29 December 2010&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:RadialDensityPREM.jpg&quot; rel=&quot;noreferrer&quot;&gt;Wikimedia's File: RadialDensityPREM.jpg&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;update:&lt;/strong&gt; &lt;a href=&quot;https://earthscience.stackexchange.com/a/15644/6031&quot;&gt;This answer to &lt;em&gt;Do there exist reasonable numbers on the density/radius/mass of the various geological layers of the Earth?&lt;/em&gt;&lt;/a&gt; provides one such model for Earth's core with two polynomials, but these end at a radius of 3480 km with nothing outside of that.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2022-09-23T08:46:31.970" LastActivityDate="2022-09-26T15:53:28.963" Title="An approximate, piecewise continuous analytical model for Earth's radial density profile useful for numerical integration?" Tags="|open-data|structural-geology|" AnswerCount="2" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="24353" PostTypeId="1" CreationDate="2022-09-23T02:19:46.693" Score="3" ViewCount="39" Body="&lt;p&gt;I had the photos below handy from a recent trip, but in other areas of northern taiwan you can see very long, thin sheets of this dark, rust-like &amp;quot;chocolate swirl&amp;quot; separating very large, fairly homogenous chunks (several meters square by who knows how deep) of &amp;quot;vanilla&amp;quot; sandstone.&lt;/p&gt;&#xA;&lt;p&gt;It looks a lot like rust - for example an old, low quality steel or iron plate that's been rusting in a field for so long that it's beginning to disintegrate, but attempts to find signs of magnetism (hold a small magnet to it to feel for attraction, or pass a cellphone over it while looking for deviations in the compass from internal magnetometer) are always negative.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Why does the sandstone in Yehliu and other scenic coastal northern Taiwan look like vanilla fudge swirl ice cream?&lt;/p&gt;&#xA;&lt;p&gt;I'm interested in the processes that make these thin, durable sheets that often seem to erode more slowly than surrounding sandstone and give them a non-sandy structure, and of course what these types of things are called.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Yehliu&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Yehliu&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://eng.taiwan.net.tw/m1.aspx?sNo=0002091&amp;amp;id=155&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://eng.taiwan.net.tw/m1.aspx?sNo=0002091&amp;amp;id=155&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://goo.gl/maps/TVtuE9BpT556nsNW9&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://goo.gl/maps/TVtuE9BpT556nsNW9&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://geohack.toolforge.org/geohack.php?pagename=Yehliu&amp;amp;params=25.2131_N_121.698_E_source:kolossus-frwiki&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://geohack.toolforge.org/geohack.php?pagename=Yehliu&amp;amp;params=25.2131_N_121.698_E_source:kolossus-frwiki&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6aKI7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6aKI7.jpg&quot; alt=&quot;snapshot from Yeiliu in northern Taiwan&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;For the images below (1 to 2 MB each) click for full size:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KZSPx.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KZSPxm.jpg&quot; alt=&quot;snapshot from Yeiliu in northern Taiwan&quot; /&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/Nxivq.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Nxivqm.jpg&quot; alt=&quot;snapshot from Yeiliu in northern Taiwan&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/KyUtL.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KyUtLm.jpg&quot; alt=&quot;snapshot from Yeiliu in northern Taiwan&quot; /&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/jFhSD.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jFhSDm.jpg&quot; alt=&quot;snapshot from Yeiliu in northern Taiwan&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/x7tJ7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/x7tJ7m.jpg&quot; alt=&quot;snapshot from Yeiliu in northern Taiwan&quot; /&gt;&lt;/a&gt; &lt;a href=&quot;https://i.stack.imgur.com/h4qfr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/h4qfrm.jpg&quot; alt=&quot;snapshot from Yeiliu in northern Taiwan&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2022-09-23T02:19:46.693" Title="Why does the sandstone in Yehliu and other scenic coastal northern Taiwan look like vanilla fudge swirl ice cream?" Tags="|rocks|sedimentology|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24354" PostTypeId="2" ParentId="24352" CreationDate="2022-09-23T07:52:07.757" Score="7" Body="&lt;p&gt;From Table I in the admittedly dated &lt;a href=&quot;https://doi.org/10.1016/0031-9201(81)90046-7&quot; rel=&quot;noreferrer&quot;&gt;Preliminary Reference Earth Model&lt;/a&gt;,&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\rho =&#xA;\begin{cases}&#xA;13.0885 - 8.8381 x^2 &amp;amp; \quad \phantom{000}0\phantom{.0} \le r &amp;lt; 1221.5 \\&#xA;12.5815 - 1.2638 x - 3.6426 x^2 - 5.5281 x^3 &amp;amp; \quad 1221.5 \le r &amp;lt; 3480.0 \\&#xA;\phantom{0}7.9565 - 6.4761 x + 5.5283 x^2 - 3.0807 x^3 &amp;amp; \quad 3480.0 \le r &amp;lt; 5701.0 \\&#xA;\phantom{0}5.3197 - 1.4836 x &amp;amp; \quad 5701.0 \le r &amp;lt; 5771.0 \\&#xA;11.2494 - 8.0298 x &amp;amp; \quad 5771.0 \le r &amp;lt; 5971.0 \\&#xA;\phantom{0}7.1089 - 3.8045 x &amp;amp; \quad 5971.0 \le r &amp;lt; 6151.0 \\&#xA;\phantom{0}2.6910 + 0.6924 x &amp;amp; \quad 6151.0 \le r &amp;lt; 6346.6 \\&#xA;\phantom{0}2.900 &amp;amp; \quad  6346.6 \le r &amp;lt; 6356.0 \\&#xA;\phantom{0}2.600 &amp;amp; \quad  6356.0 \le r &amp;lt; 6368.0 \\&#xA;\phantom{0}1.020 &amp;amp; \quad 6291.0 \le r \le 6371.0 \\&#xA;\end{cases}&#xA;$$&lt;/span&gt;&#xA;where&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; is the density in grams per cubic centimeter,&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; is distance from the center of the Earth to the point of interest in kilometers, and&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; is the normalized radius: &lt;span class=&quot;math-container&quot;&gt;$x\equiv\frac r {6371}$&lt;/span&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;As each element is a polynomial, this is a piecewise continuous model of density inside the Earth from the center to the surface. There are however discontinuities at the transitions.&lt;/p&gt;&#xA;&lt;p&gt;A plot of PREM density as a function of radial distance is portrayed below.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Kq1aV.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Kq1aV.png&quot; alt=&quot;PREM density model, density in g/cc as a function of radial distance in km&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I generated this using the following python script:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;from matplotlib import pyplot as plt&#xA;&#xA;def density(r) :&#xA;    x = r / 6371.0&#xA;    if r &amp;lt; 1221.5 :&#xA;        rho = 13.0885 - x*x*8.8381&#xA;    elif r &amp;lt; 3480.0 :&#xA;        rho = 12.5815 - x*(1.2638 + x*(3.6426 + x*5.5281))&#xA;    elif r &amp;lt; 5701.0 :&#xA;        rho = 7.9565 - x*(6.4761 - x*(5.5283 - x*3.0807))&#xA;    elif r &amp;lt; 5771.0 :&#xA;        rho = 11.2494 - x*8.0298&#xA;    elif r &amp;lt; 6151.0 :&#xA;        rho = 7.1089 - x*3.8045&#xA;    elif r &amp;lt; 6346.6 :&#xA;        rho = 2.6910 + x*0.6924&#xA;    elif r &amp;lt; 6356.0 :&#xA;        rho = 2.900&#xA;    elif r &amp;lt; 6368.0 :&#xA;        rho = 2.600&#xA;    else :&#xA;        rho = 1.020&#xA;    return rho&#xA;&#xA;def main() :&#xA;    r = [float(x) for x in range(6372)]&#xA;    rho = [density(x) for x in r]&#xA;    plt.plot(r, rho)&#xA;    plt.ylabel('rho (g/cc)')&#xA;    plt.xlabel('r (km)')&#xA;    plt.title('PREM density')&#xA;    plt.grid()&#xA;    plt.savefig('prem_dens.png')&#xA;    plt.show()&#xA;&#xA;if __name__ == &amp;quot;__main__&amp;quot; :&#xA;    main()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2022-09-23T09:20:53.960" LastActivityDate="2022-09-23T09:20:53.960" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24355" PostTypeId="1" CreationDate="2022-09-23T14:56:13.833" Score="4" ViewCount="69" Body="&lt;p&gt;When hiking in the Moselvalley (on the &lt;a href=&quot;https://www.google.com/maps/place/Calmont+Klettersteig/@50.108568,7.1250698,14z/data=!4m6!3m5!1s0x47be397c34e6ff43:0x23896a30bc7c2842!8m2!3d50.1074872!4d7.1252098!16s%2Fg%2F11gvy16vv6&quot; rel=&quot;nofollow noreferrer&quot;&gt;Calmont&lt;/a&gt;, to be precise) I found a slightly rhomboid piece of slate measuring about 10 by 11 cm, with a thickness of ca. 2 to 4 cm.&lt;/p&gt;&#xA;&lt;p&gt;As can be seen in the first photograph, there's a S-shaped chain of &amp;quot;chippings&amp;quot;, which might resemble a tail, a long neck or... I don't know what. Maybe someone sometime was bored and practiced stone hewing.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fvoip.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fvoip.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The &amp;quot;chippings&amp;quot; are about 3 to 6 mm deep and while not identical, quite similar in shape and size. Their arrangement looks to me rather organic, but I am no expert.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eyr84.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eyr84.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;For completeness, this is the back side of the piece of slate.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9m6HW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9m6HW.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I know that slate deposits tend to contain fossils and wonder if I got lucky, or if I am seeing something that isn't there.&lt;/p&gt;&#xA;" OwnerUserId="14194" LastActivityDate="2022-10-14T04:38:02.443" Title="Regular-ish chipings in slate - weird weathering, hewn or a fossil?" Tags="|geology|fossils|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24356" PostTypeId="2" ParentId="24175" CreationDate="2022-09-23T19:09:49.950" Score="0" Body="&lt;p&gt;I actually found another reason that this error occurs: processing timestep. The timestep control in MIKE-hydro. If fixing cross sections doesn't work, then adjust the timestep length to something that works for your computer. The default is 10 minutes. Mine runs on 30 seconds, where I was previously getting errors about cross sections and exceeding water level maxima.&lt;/p&gt;&#xA;" OwnerUserId="27288" LastActivityDate="2022-09-23T19:09:49.950" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24357" PostTypeId="1" CreationDate="2022-09-24T03:43:05.233" Score="4" ViewCount="718" Body="&lt;p&gt;Phys.org's story from September 23, 2022 entitled &lt;a href=&quot;https://phys.org/news/2022-09-mexico-earthquake-triggers-tsunami-miles.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mexico earthquake triggers 'desert tsunami' 1,500 miles away in Death Valley cave&lt;/a&gt; includes the following:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;About five minutes after the 7.6 magnitude earthquake hit near Mexico's southwest coast Monday, typically calm water deep in a Death Valley National Park cave started sloshing against the surrounding limestone rock.&lt;/p&gt;&#xA;&lt;p&gt;The reverberations from the earthquake more than 1,500 miles away created what experts have called a &amp;quot;desert tsunami,&amp;quot; which on Monday made waves erupt up to 4 feet high in the cave known as Devils Hole, a pool of water about 10 feet wide, 70 feet long and more than 500 feet deep, in Amargosa Valley, Nevada.&lt;/p&gt;&#xA;&lt;p&gt;The water in the partially filled cave has become an &amp;quot;unusual indicator of seismic activity&amp;quot; across the world, with earthquakes across the globe—as far as Japan, Indonesia and Chile—causing the water to splash up Devils Hole, according to the National Park Service website.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;It depends on the depth, magnitude and location around the world,&amp;quot; Wilson said. He said typically earthquakes along the Pacific's &amp;quot;Ring of Fire&amp;quot; that reach at or above a magnitude 7 will register in Devils Hole.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; How did they know that there was a &amp;quot;desert tsunami&amp;quot; in a  Death Valley cave after a  7.6 magnitude earthquake near the southwest of Mexico?&lt;/p&gt;&#xA;&lt;p&gt;I'm wondering if there are video cameras inside, or water height sensors that record wave height, or was there just a puddle of water outside the opening in the morning?&lt;/p&gt;&#xA;&lt;p&gt;Since the article begins &amp;quot;About five minutes after the 7.6 magnitude earthquake hit...&amp;quot; it suggests there were some type of live data collected, although that could simply be an estimate somehow?&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6298" LastEditDate="2022-09-24T14:05:14.473" LastActivityDate="2022-09-26T08:25:59.657" Title="How did they know that there was a &quot;desert tsunami&quot; in a Death Valley cave after a 7.6 magnitude earthquake near the southwest of Mexico?" Tags="|earthquakes|measurements|instrumentation|cavern|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24359" PostTypeId="2" ParentId="24357" CreationDate="2022-09-24T08:01:53.377" Score="6" Body="&lt;p&gt;The news section of the Death Valley National Park website has the story: &lt;a href=&quot;https://www.nps.gov/deva/learn/news/9-19-2022.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mexican earthquake sloshes Devils Hole&lt;/a&gt;. There is footage of the waves at the end of the page. Here is a screenshot from &lt;a href=&quot;https://www.nps.gov/nps-audiovideo/audiovideo/398877af-a57f-4ed8-8a6d-d5398fae46e3480p.mp4&quot; rel=&quot;nofollow noreferrer&quot;&gt;the video&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YKwYn.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YKwYn.jpg&quot; alt=&quot;NPS photo by Ambre Chaudoin, public domain&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;NPS photo by Ambre Chaudoin, public domain&lt;/em&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit&lt;/strong&gt;: At first I thought that this was the answer to how did they know that there was a &amp;quot;desert tsunami&amp;quot; (a seiche) in a Death Valley cave after a 7.6 magnitude earthquake: they had visual information from the video camera. However, as @uhoh noted in a comment, they also know that another earthquake &lt;em&gt;did not trigger&lt;/em&gt; a seiche, and this one occurred at 1 am, so they could not know that through visual output only. Indeed, water level in the cave has been monitored for a while. From &lt;a href=&quot;https://scholar.colorado.edu/concern/graduate_thesis_or_dissertations/v979v3214&quot; rel=&quot;nofollow noreferrer&quot;&gt;Matthew Weingarten PhD dissertation&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Since August 1989, the National Park Service has monitored the water&#xA;level in Devils Hole with multiple instruments. Continuous water level&#xA;was recorded by a float-pulley device and an accompanying strip chart&#xA;recorder (Fig. 2.2). The strip chart recorder graphically records&#xA;real-time water level relative to a fixed elevation. The majority of&#xA;the water level was recorded on 0.0005 m of strip chart per 30&#xA;minutes. The resolution of the float-pulley device is 0.003 m and the&#xA;maximum possible recorded water level fluctuation recorded is 0.3 m&#xA;(16). Two pressure transducers and an electronic data logger were also&#xA;added to record water levels to the nearest 0.0003 m on 15-minute&#xA;intervals. The strip chart recorder was removed in May 2010. In&#xA;December 2012 a new pressure transducer was installed and a data&#xA;logger reprogrammed to record water level at 1-second (1 Hz) intervals&#xA;when an offset of 0.003 m was detected. The updated monitoring&#xA;protocol records higher frequency, digital water level data.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The monitoring setup is shown on figure 2.2, while some examples of water level response to earthquakes is shown on figure 2.3 (not included here because of copyright). Alternatively, there is also a publication on the same topic (&lt;a href=&quot;https://doi.org/10.1002/2013GL058418&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weingarten &amp;amp; Ge, 2014&lt;/a&gt;), but the photo of the setup was not included.&lt;/p&gt;&#xA;&lt;p&gt;Bottom-line is: &lt;strong&gt;they know that some earthquakes do trigger seiches at Devils Hole, and that some don't, because the water level of the cave is monitored in near real-time&lt;/strong&gt;.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2022-09-26T08:25:59.657" LastActivityDate="2022-09-26T08:25:59.657" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24360" PostTypeId="2" ParentId="24347" CreationDate="2022-09-24T15:59:23.370" Score="5" Body="&lt;p&gt;First off, the geostationary Moon would have to be 115 times less massive as the actual one to match the gravitational pull.&lt;/p&gt;&#xA;&lt;p&gt;With that, one effect would be that the &lt;em&gt;tidal&lt;/em&gt; pull would be stronger, but also the tides would not move across the face of the Earth as we are used to seeing.&lt;/p&gt;&#xA;&lt;p&gt;First, consider the strength of the tidal pull. The tidal pull across Earth imparted by any other massive body is proportional not to the overall gravitation acceleration imparted by the other body onto Earth, but to the &lt;em&gt;difference&lt;/em&gt; in gravitational acceleration between one part of Earth and another. That difference is inversely proportional to the &lt;em&gt;cube&lt;/em&gt; of the distance to the other body, not the square of the distance as the bulk gravitational acceleration would be.&lt;/p&gt;&#xA;&lt;p&gt;So the geosynchronous Moon, scaled down in mass by 115 times to match the squared distance and overall gravitational acceleration, ends up generating a difference across the Earth more than ten times as large as the actual Moon because that difference contains an extra power of the distance. Hence a larger tidal height.&lt;/p&gt;&#xA;&lt;p&gt;However, the &amp;quot;tidal wave&amp;quot; would not wash over the Earth as it does with the actual Moon. If the Moon were truly geosynchronous, the high and low tides -- enhanced by the closer distance even if we normalize the Moon's gravitational pull -- would also be locked in place on Earth's surface, meaning wherever there is a high tide there will always be a high tide and vice versa. In effect the whole Earth would be given a permanent tidal stretch. The resulting combination of enhancing the tidal wave combined with freezing it into place might therefore leave a specific portion of the ocean shore either permanently flooded or permanently &amp;quot;high and dry.&amp;quot;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;We don't really need to move the Moon to see the effect of relative distances on tidal strength. We can also see this effect with the actual Moon and Sun.&lt;/p&gt;&#xA;&lt;p&gt;In terms of overall gravity exerted on the Earth, the Moon is puny having less than 1% of the gravitational pull exerted by the Sun. Yet our tides are caused mostly by the Moon because the Moon is 400 times closer than the Sun. The cubic rather than quadratic effect of tidal forces with distance enhances the Moon's contribution enough to beat the more distant Sun.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2022-09-25T09:51:11.920" LastActivityDate="2022-09-25T09:51:11.920" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24361" PostTypeId="1" AcceptedAnswerId="24369" CreationDate="2022-09-24T17:20:38.230" Score="3" ViewCount="2068" Body="&lt;p&gt;Taiwan's main island is about 100 km from China. Is it possible to see it if you are at a scenic viewing spot in China on a clear day?&lt;/p&gt;&#xA;&lt;p&gt;This image, from a Reuters article, shows people on Pingtan Island in Fujian province, mainland China and is ambiguous. Are those islands on the far horizon (circled) the Taiwan main island or is it the Kinmen Islands (also Taiwan's territory)?&lt;/p&gt;&#xA;&lt;p&gt;So are these hills I'm seeing 100 km out to sea or only 10 km?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7jWDG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7jWDG.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Img source: &lt;a href=&quot;https://www.reuters.com/world/asia-pacific/across-sea-taiwan-chinese-tourists-await-islands-return-2022-08-05/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.reuters.com/world/asia-pacific/across-sea-taiwan-chinese-tourists-await-islands-return-2022-08-05/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="10835" LastEditorUserId="6298" LastEditDate="2022-09-26T21:24:10.287" LastActivityDate="2022-09-26T21:24:10.287" Title="Can you see the main island of Taiwan from China?" Tags="|geography|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24362" PostTypeId="1" CreationDate="2022-09-24T20:29:36.737" Score="3" ViewCount="33" Body="&lt;p&gt;I want to know the precise spectra density of light we humans (and plants) are exposed to at various times throughout the day from morning to evening. I'm searching for spectral density graphs/spreadsheets on early morning daylight, noon daylight, evening daylight, etc. as (measured from around sea-level or anywhere on Earth's terrestrial surface in the USA or similar). I'm finding it very difficult to find this kind of raw data, and I know it has to be somewhere on the internet. I'm still inexperienced in research, and I've been spoiled by the ease of Google all my life. Any help would be much appreciated.&lt;/p&gt;&#xA;&lt;p&gt;Thank you very much.&lt;/p&gt;&#xA;" OwnerUserId="27678" LastActivityDate="2022-09-26T10:21:39.247" Title="Where may I find spreadsheet data on the spectral density of daylight at various times throughout the day from morning to evening?" Tags="|light|weatherdata|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24364" PostTypeId="2" ParentId="24357" CreationDate="2022-09-25T08:39:08.653" Score="3" Body="&lt;p&gt;As to the how did they know, and how did they register:&#xA;The observations are a byproduct of the conservation efforts at the cave. The Devils Hole pupfish are an endangered species that are observed by biologists.&lt;/p&gt;&#xA;&lt;p&gt;From Wikipedia's &lt;a href=&quot;https://en.wikipedia.org/wiki/Devils_Hole_pupfish#Threats&quot; rel=&quot;nofollow noreferrer&quot;&gt;Devils Hole pupfish; Threats&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In addition to the indirect threat of groundwater depletion, human actions can impact the pupfish in other ways as well. A 2004 flash flood swept scientific monitoring equipment into Devils Hole, causing the deaths of an estimated eighty pupfish.[40] In April 2016, three men broke into the Devils Hole protected area, destroying scientific equipment and wading onto the shallow shelf of Devils Hole, smashing pupfish eggs and larvae, as well as vomiting into the water.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The effects of seismic activity on the water of the cave affects these pupfish, and is a regular known phenomenon.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://knewz.com/water-bounced-off-rocks/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Waves Crash Against Rocks In U.S. National Park's Devils Hole After Earthquake Shook Mexico&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.cbsnews.com/news/mexico-earthquake-triggers-4-foot-waves-death-valley-national-park/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mexican earthquake triggers 4-foot waves in Death Valley National Park — 1,500 miles away&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aE3u8.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aE3u8.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Nearly the entire natural range of the species is visible in this photo. The equipment is used to monitor the water level.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Devils_Hole_(13987389476).jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27683" LastEditorUserId="18088" LastEditDate="2022-09-26T01:29:38.250" LastActivityDate="2022-09-26T01:29:38.250" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24365" PostTypeId="1" AcceptedAnswerId="24366" CreationDate="2022-09-25T17:12:22.890" Score="6" ViewCount="91" Body="&lt;p&gt;I know that the Jovian ice moons have been speculated to have cryovolcanos. I was thinking of the ice planet of Hoth from Star Wars and in one of the video games; it has regular volcanic activity. However, it’s still an ice world so can an ice planet have cryovolcanos along with regular volcanos?&lt;/p&gt;&#xA;" OwnerUserId="27686" LastActivityDate="2022-09-26T08:51:08.733" Title="Can a planet have both magma volcanoes and cryovolcanos?" Tags="|geophysics|volcanology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24366" PostTypeId="2" ParentId="24365" CreationDate="2022-09-26T08:51:08.733" Score="3" Body="&lt;p&gt;Sure, it's entirely possible. According to theory ice volcanoes are caused by the buildup of pressure from some sort of heat source. Most that we know of are caused by tidal forces, intense gravity from Jupiter or Saturn squishing a moon. A rupture forms on the surface of the ice and pressure is released in the form of a plume. Enceladus (a moon of Saturn) has cryovolcanism, the theory is that the heat comes from its core rather then tidal forces, not volcanism exactly. There's no reason that the heat couldn't come from volcanism, we just have no examples in our solar system.&lt;/p&gt;&#xA;&lt;p&gt;If you took Earth and pushed its orbit out past the ice line you'd get a world like you describe. There would be surface volcanoes and under-water volcanoes that would cause ice geysers through the oceans' thick crusts of ice.&lt;/p&gt;&#xA;" OwnerUserId="27024" LastActivityDate="2022-09-26T08:51:08.733" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24367" PostTypeId="1" CreationDate="2022-09-26T09:50:07.587" Score="1" ViewCount="111" Body="&lt;p&gt;I am looking for a meteorological measure of daylight brightness/luminosity. I can only find measures that are defined by the number of hours of sunlight during a day, but is there a measure that also captures the fact that particular regions of the world, far from the equator, have not only less daylight at some point during the year, but also less brightness, or luminosity, meaning that the sun is further down or up in the sky.&lt;/p&gt;&#xA;&lt;p&gt;Maybe something close to a measure of &lt;a href=&quot;https://en.wikipedia.org/wiki/Albedo&quot; rel=&quot;nofollow noreferrer&quot;&gt;albedo&lt;/a&gt; at certain points in time and place?&lt;/p&gt;&#xA;" OwnerUserId="27692" LastEditorUserId="18081" LastEditDate="2022-09-26T15:36:01.627" LastActivityDate="2022-09-27T16:01:13.077" Title="Measure of daylight brightness" Tags="|meteorology|sun|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24368" PostTypeId="2" ParentId="24362" CreationDate="2022-09-26T10:21:39.247" Score="2" Body="&lt;p&gt;You probably can take the data outputs of this awesome tool to your problem. It is the &lt;a href=&quot;https://re.jrc.ec.europa.eu/pvg_tools/en/tools.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Photovoltaic Geographical Information System&lt;/a&gt; , designed to calculate solar energy input to photovoltaic instasllations. But on the right of the map, you have a vertical menu to choose between monthly, daily, hourly, and year data.&lt;/p&gt;&#xA;&lt;p&gt;First choose location in the map, you can display global irradiance, only direct light, and more. You can also play with inclinations and horizon shadows, losses, temperatures,...&lt;/p&gt;&#xA;&lt;p&gt;It is very complete, so probably it worths to look at the documnetation linked in the horizontal menu.&lt;/p&gt;&#xA;" OwnerUserId="27465" LastActivityDate="2022-09-26T10:21:39.247" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24369" PostTypeId="2" ParentId="24361" CreationDate="2022-09-26T15:36:14.883" Score="2" Body="&lt;p&gt;If the location of the photo is accurate, as Pingtan Island, it is unlikely you could see the Kinmen Islands, as they are on a different bit of coast. They certainly wouldn't be 'out at sea'.  The centre of Taiwan has elevations of over 2000 metres, which on a clear day could be visible from sea level at a range of 160 kilometres, so  that's probably what you are seeing in the picture, though it would have had to be a very clear day.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2022-09-26T15:36:14.883" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24370" PostTypeId="2" ParentId="24352" CreationDate="2022-09-26T15:53:28.963" Score="2" Body="&lt;p&gt;If you want access to the raw data, the Preliminary Reference Earth Model (and many other more refined models) are available on the IRIS website:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://ds.iris.edu/ds/products/emc-prem/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://ds.iris.edu/ds/products/emc-prem/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;For example you can download the file PREM_1s_IDV.csv&lt;/p&gt;&#xA;&lt;p&gt;Each line represents a depth and a density value at this depth (columns &amp;quot;depth and &amp;quot;density&amp;quot;). From this you can construct a piecewise discontinuous linear model, or directly use them for a numerical integration.&lt;/p&gt;&#xA;" OwnerUserId="4551" LastActivityDate="2022-09-26T15:53:28.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24372" PostTypeId="2" ParentId="20145" CreationDate="2022-09-27T04:22:51.837" Score="1" Body="&lt;p&gt;Just a heads up, but the terminology ('four-way closure', 'pericline') both you and the other responder are using are either pretty antiquated or some sort of petroleum geology 'shop talk'.&lt;/p&gt;&#xA;&lt;p&gt;A four-way closure would more commonly be referred to as a dome by structural geologists. You can think of a dome as a type of anticline that is doubly plunging in such a way that the wavelength of folding along what we might normally call its hinge is approximately equal to that of its wavelength in the direction perpendicular to its hinge. In simpler terms, it is essentially an equant 'mound' that may be formed either by domal uplift of sediment or magma, or by two superimposed and mutually perpendicular generations of folds.&lt;/p&gt;&#xA;&lt;p&gt;The term 'pericline' mentioned by the previous user rarely refers to a doubly plunging anticline that is elongate in one direction (i.e., not an ideal dome). Structural geologists would almost always refer to this simply as a doubly plunging anticline.&lt;/p&gt;&#xA;&lt;p&gt;I am not familiar with seismic imaging techniques, but intuitively it would seem that a dome or four-way closure would show up as an anticline of equal openness in two perpendicular section images; if it were just an anticline, it would only appear folded in one orientation.&lt;/p&gt;&#xA;" OwnerUserId="27389" LastActivityDate="2022-09-27T04:22:51.837" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24373" PostTypeId="2" ParentId="24367" CreationDate="2022-09-27T05:11:54.110" Score="0" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;I am looking for a meteorological measure of daylight brightness/luminosity...but is there a measure that also captures the fact that particular regions of the world, far from the equator, have not only less daylight at some point during the year, but also less brightness, or luminosity, meaning that the sun is further down or up in the sky.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Consider the following -&lt;/p&gt;&#xA;&lt;p&gt;Radio Corporation of America, 1968 (and in later years), RCA Electro-Optics Handbook. Section 6.  Sources of Radiation, p.6-10ff, fig. 6-10, Atmospheric Transmittance.&lt;/p&gt;&#xA;&lt;p&gt;Note: The image (below) is from a republication by RCA ca. 1974, p 74.  Please note the original source reference, Bond and Henderson, 1963, given below.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hmvqg.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hmvqg.jpg&quot; alt=&quot;illuminance, due to sun, moon, &amp;amp; sky, at surface of the earth.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;ol start=&quot;16&quot;&gt;&#xA;&lt;li&gt;Bond, D.S. and Henderson, F.P., THE CONQUEST OF DARKNESS, AD 346297,&#xA;Defense Documentation Center, Alexandria, Va., 1963.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="27699" LastActivityDate="2022-09-27T05:11:54.110" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24374" PostTypeId="2" ParentId="24367" CreationDate="2022-09-27T16:01:13.077" Score="1" Body="&lt;p&gt;Perhaps you may be interested in downward shortwave flux? It isn't easy to compute or measure, but it should capture what you are after. You can use the equation &lt;span class=&quot;math-container&quot;&gt;$$R_{net}=S\downarrow-S\uparrow+L\downarrow-L\uparrow$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$S$&lt;/span&gt; represents shortwave, &lt;span class=&quot;math-container&quot;&gt;$L$&lt;/span&gt; represents longwave, &lt;span class=&quot;math-container&quot;&gt;$R_{net}$&lt;/span&gt; is the net radiation, and the arrows depict upward or downward. If you assume an albedo &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt;, you can say that &lt;span class=&quot;math-container&quot;&gt;$S\uparrow$&lt;/span&gt; is a fraction of &lt;span class=&quot;math-container&quot;&gt;$S\downarrow$&lt;/span&gt;: &lt;span class=&quot;math-container&quot;&gt;$$R_{net}=S\downarrow(1-\alpha)+L\downarrow-L\uparrow$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;If you use an IR thermometer, you can measure the temperature of the sky (&lt;span class=&quot;math-container&quot;&gt;$T_{sky}$&lt;/span&gt;) and the ground (&lt;span class=&quot;math-container&quot;&gt;$T_{ground}$&lt;/span&gt;). If you assume a corresponding emissivity (\epsilon), then you can invoke Stefan-Boltzmann's &amp;quot;law&amp;quot; and get &lt;span class=&quot;math-container&quot;&gt;$$R_{net}=S\downarrow(1-\alpha)+\sigma\left(\epsilon_{sky}T_{sky}^4-\epsilon_{surface}T_{surface}^4\right)$$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;If you measure &lt;span class=&quot;math-container&quot;&gt;$R_{net}$&lt;/span&gt; using a net radiometer, you can solve for &lt;span class=&quot;math-container&quot;&gt;$S\downarrow$&lt;/span&gt;. Alternatively, you can also compute &lt;span class=&quot;math-container&quot;&gt;$S\downarrow$&lt;/span&gt; empirically, like some of the climate models do. But that is perhaps the most computationally intensive part of climate modeling.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2022-09-27T16:01:13.077" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24375" PostTypeId="1" CreationDate="2022-09-28T15:36:00.910" Score="2" ViewCount="38" Body="&lt;p&gt;In the Atlantic basin, tropical cyclones start in the east and move west until they either reach land or move north into cooler waters.&lt;/p&gt;&#xA;&lt;p&gt;Based on &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropical_cyclogenesis#/media/File:Global_tropical_cyclone_tracks-edit2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;this map of historic paths&lt;/a&gt;, there is a lot of cyclogensis in the east Pacific.  However, these paths all end before cyclones reach land, and they also don't curve northward into cooler waters as much as cyclones in the Atlantic basin.  So how do they die out?  Moreover, why don't cyclones form in warm parts of the central Pacific?&lt;/p&gt;&#xA;" OwnerUserId="18810" LastEditorUserId="2470" LastEditDate="2022-09-28T20:35:54.760" LastActivityDate="2022-09-28T20:35:54.760" Title="Why do east Pacific cyclones/hurricanes die out?" Tags="|tropical-cyclone|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24376" PostTypeId="1" CreationDate="2022-09-28T16:56:40.477" Score="8" ViewCount="227" Body="&lt;p&gt;Thomas L. Friedman, the New York Times columnist, &lt;a href=&quot;https://www.nytimes.com/2022/09/27/opinion/ukraine-war-environment.html?smid=url-share&quot; rel=&quot;noreferrer&quot;&gt;wrote yesterday&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;These intact forests — from those in the Amazon and Congo River basins to ones in Canada, Russia and Ecuador — are the world’s life-support system. &lt;strong&gt;They sponge billions of tons of carbon dioxide out of the atmosphere,&lt;/strong&gt; generating oxygen [...].&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;A forest would, over longer time periods, only be a net carbon sink — and corresponding oxygen source — if its biomass increases and/or if dead organic material is removed from the global cycle of matter, e.g. by forming peat underground.&lt;/p&gt;&#xA;&lt;p&gt;But, for example, parts of the Amazon rain forest stand basically on a relatively thin   layer of humus above infertile quartz sand (&lt;a href=&quot;https://www.dw.com/en/the-amazon-nutrient-rich-rainforests-on-useless-soils/a-50139632&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; is a popular science article); since the rain forest is millions of years old, there is no significant sequestering of organic matter over time in the Amazon.&lt;/p&gt;&#xA;&lt;p&gt;Of course I may have overlooked something, and rain forests in Africa or Asia, let alone forests in temperate climates, all in places with very different geologies, may indeed sequester carbon. After all, our fossil fuels once were plants.&lt;/p&gt;&#xA;&lt;p&gt;Are forests overall significant carbon sinks or should I write a letter to the editor? I suppose that Friedman should at least remove the Amazon basin from the sentence.&lt;/p&gt;&#xA;" OwnerUserId="5396" LastEditorUserId="5396" LastEditDate="2022-09-28T19:20:33.860" LastActivityDate="2023-07-27T08:21:04.073" Title="Do the large forests remove CO2 from the atmosphere?" Tags="|co2|biomass|rainforest|" AnswerCount="3" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="24377" PostTypeId="2" ParentId="24376" CreationDate="2022-09-28T22:01:45.417" Score="0" Body="&lt;p&gt;The article is doesn't say forests are carbon sinks, the quote says forests convert large amounts of CO2 into oxygen, which is completely correct. I didn't read the article but I suspect the point the author is making is that cutting down forests will accelerate CO2 buildup in the atmosphere, which is also correct.&lt;/p&gt;&#xA;&lt;p&gt;Saying that forests process billions of tons of CO2 is right, that doesn't mean they are converting those billions of tons into sequestered carbon every year, it's being processed into food to sustain the tree and provide for growth. The natural process of carbon sequestration is actually pretty slow.&lt;/p&gt;&#xA;" OwnerUserId="27024" LastActivityDate="2022-09-28T22:01:45.417" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24379" PostTypeId="1" CreationDate="2022-09-29T09:19:02.047" Score="2" ViewCount="96" Body="&lt;p&gt;Why doesn't (e.g.) the equatorward North Atlantic Deep Water bend more to the west?&lt;/p&gt;&#xA;&lt;p&gt;Is it maybe because the water tends to move relatively slowly and the magnitude of the Coriolis effect depends on the speed of the flow of water?&lt;/p&gt;&#xA;" OwnerUserId="27611" LastActivityDate="2022-09-29T09:19:02.047" Title="(Why) is the thermohaline circulation not affected by the coriolis effect?" Tags="|oceanography|ocean-currents|coriolis|thermohaline-circulation|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24380" PostTypeId="1" CreationDate="2022-09-29T15:34:14.543" Score="5" ViewCount="139" Body="&lt;p&gt;I was looking at the radar on the Weather Channel website and I noticed something that I don't think I've ever seen before.&lt;/p&gt;&#xA;&lt;p&gt;Screen shot from 11:30 AM EST 9/29&#xA;&lt;a href=&quot;https://i.stack.imgur.com/G17NS.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G17NS.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Hurricane/Tropical Storm Ian can be seen in the lower left of the screenshot.  However, there appears to be a massive tail that extends from the storm, with the tail reaching as far north as Boston.&lt;/p&gt;&#xA;&lt;p&gt;Is this typical of hurricanes?  Is this a glitch in the radar?  Is this unrelated to Ian?  Or is this something rare?&lt;/p&gt;&#xA;" OwnerUserId="27709" LastActivityDate="2022-09-29T15:34:14.543" Title="Why does Hurricane Ian show a long tail off to the North-East on doppler radar?" Tags="|meteorology|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24381" PostTypeId="1" CreationDate="2022-09-29T19:33:15.150" Score="3" ViewCount="133" Body="&lt;p&gt;There’s plenty of carbon dioxide and radiation throughout the solar system, why is it a phenomena only associated with the outer planets?&lt;/p&gt;&#xA;" OwnerUserId="27711" LastActivityDate="2022-10-14T05:55:15.693" Title="Why are there no tholins in the inner solar system?" Tags="|planetary-science|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24382" PostTypeId="1" CreationDate="2022-09-30T11:41:15.077" Score="4" ViewCount="359" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Eldon_Hill&quot; rel=&quot;nofollow noreferrer&quot;&gt;Eldon Hill is a limestone hill in Derbyshire, England&lt;/a&gt;. It has a large quarry on it's NW side and a natural pothole just to the south of it's peak. It also has the remains of lead mines scattered across it.&lt;/p&gt;&#xA;&lt;p&gt;The image below (&lt;a href=&quot;https://www.google.com/maps/@53.3268387,-1.8246639,681m/data=!3m1!1e3&quot; rel=&quot;nofollow noreferrer&quot;&gt;from this location on Google Maps&lt;/a&gt;) shows a number of horizontal, linear bands (marked with yellow arrows) of what appear to be indentations in the ground running across the surface of the hill for a distance of ~300m each. What are they, and how were they formed?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cr3II.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cr3II.jpg&quot; alt=&quot;Eldon Hill, Derbyshire&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27715" LastEditorUserId="18081" LastEditDate="2022-09-30T12:10:20.850" LastActivityDate="2022-10-01T09:55:45.930" Title="What are these features on Eldon Hill?" Tags="|geomorphology|limestone|satellite-oddities|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24383" PostTypeId="1" CreationDate="2022-09-30T13:52:12.890" Score="1" ViewCount="27" Body="&lt;p&gt;Calcium carbonate in cement can make the soil more alkaline but does that make large housing developments have a significant or negligible affect on availability of nutrients? Does it cause nutrients to be more available to plants or does it end up leaching them away?&lt;/p&gt;&#xA;" OwnerUserId="27717" LastEditorUserId="22648" LastEditDate="2022-10-02T15:41:26.173" LastActivityDate="2022-10-02T15:41:26.173" Title="How do housing developments affect the soil of the surroundings? Are the minerals/molecules in cement available to plants? Or is the soil too basic?" Tags="|soil|minerals|plant|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24384" PostTypeId="2" ParentId="24382" CreationDate="2022-09-30T14:15:52.127" Score="9" Body="&lt;p&gt;These are marked up on the British Geological Survey's mapping as mineral veins cutting through the limestones, and in the &lt;a href=&quot;https://webapps.bgs.ac.uk/Memoirs/docs/B01556.html&quot; rel=&quot;noreferrer&quot;&gt;associated memoir&lt;/a&gt; as sulphide ore veins. The surface expression that shows on the imagery is likely the remains of &lt;a href=&quot;https://her.derbyshire.gov.uk/Monument/MDR2292&quot; rel=&quot;noreferrer&quot;&gt;shallow mining&lt;/a&gt; and pits exploring or exploiting the ores.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2022-09-30T14:15:52.127" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24385" PostTypeId="2" ParentId="24382" CreationDate="2022-10-01T09:55:45.930" Score="1" Body="&lt;p&gt;To complete Andy's answer: &lt;a href=&quot;https://pdmhs.co.uk/MiningHistory/Bulletin%2014-5%20-%20A%20History%20and%20Gazetteer%20of%20the%20Mines%20in%20the%20Liberty%20of%20Peak%20Forest,%20Derbyshire%20-%201605%20to%201878.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;A History and Gazetteer of the Mines in the Liberty of Peak Forest, Derbyshire&lt;/a&gt;, (Heathcote, 2001), published in the bulletin of the Peak District Mines Historical Society. The area of Eldon Hill is shown on figure 5. The three veins marked on your image are, from North to South:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Eldon Bent Vein&lt;/li&gt;&#xA;&lt;li&gt;Burning Drake Vein&lt;/li&gt;&#xA;&lt;li&gt;Wrangling Rake&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Details about these veins can be found at pages 9&lt;span class=&quot;math-container&quot;&gt;$-$&lt;/span&gt;10. Basically, those features are the surface expression of ancient lead mining activities in the area.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2022-10-01T09:55:45.930" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24386" PostTypeId="1" CreationDate="2022-10-01T21:12:17.623" Score="1" ViewCount="34" Body="&lt;p&gt;We have written a free textbook at (&lt;a href=&quot;http://climate-change.world&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://climate-change.world&lt;/a&gt;).  Its main focus is on the social science side of changing emissions.  We are not atmospheric scientists, so all we want to do is to adopt and convey the IPCC RCP framework (not SCP).&lt;/p&gt;&#xA;&lt;p&gt;One simple way to convey global warming is to plot the representative global mean temperature forecast on the different representative concentration pathways until 2200, ideally with some sort of confidence intervals.  presumably, this would be three annual time-series (low, median, high) for each RCP.  I do not want finer-grained information, e.g., at different locations, but I do want to be able to update this plot every year.&lt;/p&gt;&#xA;&lt;p&gt;Given that the global temperature increase is at one center of the public interest and debate, I find the authoritative IPCC RCP temperature forecast (and sea level) data surprisingly difficult to locate.  I would have thought this would be front and center.&lt;/p&gt;&#xA;&lt;p&gt;Given that our current version may be outdated by a few years, could someone please point me to where one should regularly obtain the current version of this data?&lt;/p&gt;&#xA;" OwnerUserId="27719" LastEditorUserId="27719" LastEditDate="2022-10-02T18:14:11.543" LastActivityDate="2022-10-02T18:14:11.543" Title="Where Do I FInd IPCC RCP Global Mean Temperature Predictions?" Tags="|climate-change|temperature|climate-data|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24387" PostTypeId="1" AcceptedAnswerId="24428" CreationDate="2022-10-02T16:17:36.227" Score="3" ViewCount="120" Body="&lt;p&gt;How is it possible that gas is stored kilometers deep? Where does all the material on top come from? If new plankton would create more gas, would the new gas be at similar depth in a few 100 million years? And would current reserves be even deeper in billions of years, perhaps 10s or 100s of km deep?&lt;/p&gt;&#xA;" OwnerUserId="27721" LastEditorUserId="6" LastEditDate="2022-10-17T11:55:05.803" LastActivityDate="2022-10-18T09:53:25.590" Title="How is it possible that natural gas fields are so deep?" Tags="|sedimentology|carbon-cycle|gas|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24388" PostTypeId="2" ParentId="24387" CreationDate="2022-10-02T17:27:07.400" Score="1" Body="&lt;p&gt;A practical limit to commercial gas/oil drilling is 30,000 ft and generally not much deeper than 20,000 ft. The high temperatures and pressures are difficult to control. There are several mechanical limits like draw works power and casing strength ( commonly 125,000 psi yield steel is used and it is not strong enough for these wells.). It would be much easier to reach methane hydrate deposits on the sea floor if you can figure out how to produce it.&lt;/p&gt;&#xA;" OwnerUserId="8409" LastActivityDate="2022-10-02T17:27:07.400" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24389" PostTypeId="2" ParentId="24381" CreationDate="2022-10-02T20:10:32.837" Score="3" Body="&lt;p&gt;Tholins are primarily polymerized hydrocarbons, and the key raw material for forming them is methane, not carbon dioxide. For a combination of physical and chemical reasons noted below, there is just not much methane to be had on the major orbiting bodies of the inner Solar Syatem.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Too hot to handle&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://physics.stackexchange.com/questions/615311/what-is-this-atmospheric-escape-chart-actually-showing&quot;&gt;This chart&lt;/a&gt; shows the combination of escape velocities and temperatures at the 1-bar pressure level on various Solar System bodies, along with bands showing the lightest gases that can be retained.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/A0sEf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/A0sEf.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Among the five major orbiting bodies in the inner Solar System, our Moon and Mercury appear far down the chart where only a gas as heavy as xenon (or possibly sulfur dioxide, which is not shown) may be retained; methane would he light enough to escape given the limited gravity and relatively warm temperature of these bodies. Mars, which is a bit more massive, comes closer, able to retain nitrogen (which is found as a minor component of its atmosphere); given the likely uncertainty in the chart maybe it could retain methane. However, the methane spikes seen on Mars are just that -- temporary, localized spikes that do not add up to a significant long-term global presence. Either the methane is escaping or it is being consumed promptly, which brings up the second barrier against methane presence and tholin formation in the inner Solar System.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Burning up&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Earth and Venus have enough gravitational heft to retain methane at their 1-bar levels, and Mars is close to the borderline ... if the local chemistry is favorable. However, methane is prone to oxidation, and there is evidence that the methane is consumed by this reaction on all three bodies that might otherwise retain it.&lt;/p&gt;&#xA;&lt;p&gt;Going back to Mars, discussed above, that planet has little or no elemental oxygen in its atmosphere. However, mineral evidence indicates oxidizing conditions on Mars. This includes most of the iron present in these minerals being oxidized to the +3 oxidation state, as in the iron oxide that reddens its surface and &lt;a href=&quot;https://space.stackexchange.com/questions/41819/how-did-spirit-and-opportunity-identify-ferric-sulfate-and-jarosite-on-mars&quot;&gt;other iron(III) minerals&lt;/a&gt; found by rovers on Mars. In addition, nitrogen has been found on an oxidized state as &lt;a href=&quot;https://www.nasa.gov/content/goddard/mars-nitrogen&quot; rel=&quot;nofollow noreferrer&quot;&gt;nitrates in Martian rock&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Earth is more straightforward. Even without burning as in a flame, methane is destroyed over time by oxygen in the atmosphere, its carbon ending as carbon dioxide.&lt;/p&gt;&#xA;&lt;p&gt;Which leaves Venus. Sulfuric acid and associated sulfur oxides also oxidize methane in the atmosphere; again most of the carbon is converted to carbon dioxide (there is a little carbon monoxide) and methane is &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Venus&quot; rel=&quot;nofollow noreferrer&quot;&gt;not reported even at parts per billion levels&lt;/a&gt;. Sulfate salts can also be oxidizing to organic matter and are actually used in this way by some anaerobic bacteria on Earth.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2022-10-14T05:55:15.693" LastActivityDate="2022-10-14T05:55:15.693" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24391" PostTypeId="1" CreationDate="2022-10-03T11:59:14.753" Score="3" ViewCount="45" Body="&lt;p&gt;Reading the Wikipedia page for some North Indian Cyclone Seasons I've come across multiple systems called &amp;quot;land depressions&amp;quot;. (written as Land [number])&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OQlKf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OQlKf.png&quot; alt=&quot;2018 Season Timeline&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Example (Land 01 2019):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/pMMnB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pMMnB.jpg&quot; alt=&quot;Land01&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I'm not exactly sure what these are. They're depressions, yes, but are they tropical, subtropical, or extratropical? I've read their references but the IMD reports never mentions if they're tropical or not. These Wikipedia articles are usually dedicated to tropical cyclones and the section on related articles even state that these articles are part of the North Indian Tropical Cyclone Seasons, and yet the JTWC does not seem to list these land depressions on their best track.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mpqqC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mpqqC.png&quot; alt=&quot;North Indian Tropical Cyclone Seasons&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Links to the Wiki articles I read:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/2018_North_Indian_Ocean_cyclone_season&quot; rel=&quot;nofollow noreferrer&quot;&gt;2018 North Indian Cyclone Season&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/2019_North_Indian_Ocean_cyclone_season#Land_Depression_01&quot; rel=&quot;nofollow noreferrer&quot;&gt;2019 North Indian Cyclone Season&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27703" LastEditorUserId="2470" LastEditDate="2022-10-03T16:47:02.967" LastActivityDate="2022-10-03T16:47:02.967" Title="What are (meteorolgical) land depressions?" Tags="|meteorology|tropical-cyclone|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24394" PostTypeId="2" ParentId="24298" CreationDate="2022-10-04T18:05:52.913" Score="1" Body="&lt;p&gt;The issue is not 100% clear. I am assuming part of the problem is that you have many areas of the same land cover type in the same subcatchment, but different parts of this cover type need to irrigated by different reservoirs.&lt;/p&gt;&#xA;&lt;p&gt;If this is the issue, one approach could be to set up your model with different land cover type codes for the different areas that are irrigated from different reservoirs. For example, if your initial land cover map has areas mapped as wheat fields, but you know which fields are specifically irrigated from three different reservoirs, you could make a land cover map that has wheat01, wheat02, and wheat03 as different &amp;quot;cover classes&amp;quot;, despite them all actually being wheat. This will mean they will be different HRU types in your model set up.&lt;/p&gt;&#xA;&lt;p&gt;To bring this into SWAT+: each of these areas would need a different grid code number in the land cover input raster, you would need to make a differently named entry for each one in the 'plant' parameter table, and then your land cover lookup table would need to link each to these different entries in the plant parameter table. In this example, if its all wheat, and you are happy with the default wheat parameters in SWAT+, you can just copy the wheat parameter row and paste it three times at the end of the table and give these new names and codes like wheat01, wheat02, wheat03.&lt;/p&gt;&#xA;&lt;p&gt;A hitch in this approach could come in automated calibration, if you are doing that. In this process, each wheat cover &amp;quot;subtype&amp;quot; (wheat01, wheat02, wheat03 for the areas irrigated by reservoirs 1,2,&amp;amp;3) would be treated as if it was an independent cover type. This means their parameter values may be changed in different ways to one another in calibration, whereas you probably want their vegetation parameters to be consistent across the three as they are all wheat... This may take some manual calibration intervention to resolve - i.e. setting the wheat01,wheat02,wheat03 parameters to be the same in the end.&lt;/p&gt;&#xA;&lt;p&gt;Also if you have many many reservoirs, there is still work to be done on linking each HRU to the right reservoir. Doing this in the text files rather than the SWAT+ Editor interface would likely faster and you could automate the process using an R or Python code. If you modify the text files outside of the Editor interface you cannot &amp;quot;write tables&amp;quot; in the Editor before running the model (if you run it from the Editor) because this will actually undo the changes you've made.&lt;/p&gt;&#xA;" OwnerUserId="27371" LastActivityDate="2022-10-04T18:05:52.913" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24395" PostTypeId="1" CreationDate="2022-10-04T20:10:36.160" Score="3" ViewCount="29" Body="&lt;p&gt;I've read that the partial pressure of oxygen in water will be the same as the partial pressure of oxygen in the atmosphere, but that the saturation of oxygen in water is dependent on factors like salinity and temperature. If the partial pressure of oxygen in water is equal to its partial pressure in the atmosphere, how is it possible that the concentration of dissolved oxygen in water can vary?&lt;/p&gt;&#xA;" OwnerUserId="26907" LastActivityDate="2022-10-04T20:10:36.160" Title="How does the partial pressure of oxygen relate to its concentration in water?" Tags="|atmosphere|oceanography|water|oxygen|gas|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24396" PostTypeId="1" CreationDate="2022-10-05T15:48:13.483" Score="1" ViewCount="69" Body="&lt;p&gt;Ok, so I'm making a data set that correlates the beer consumption level of a country to the weather of the country, but the weather statistics I have don't correlate as much as I would like.&#xA;These statistics are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Maximum temperature of the day&lt;/li&gt;&#xA;&lt;li&gt;Minimum temperature of the day&lt;/li&gt;&#xA;&lt;li&gt;Mean temperature of the day&lt;/li&gt;&#xA;&lt;li&gt;Precipitation&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;So, are there any new statistics I can calculate from these ones? (I would prefer actual weather statistics that are used by experts but if not don't worry, I'll accept all ideas :) )&lt;/p&gt;&#xA;&lt;p&gt;P.D: Here's the ones I've already tried so these don't count:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;MaxTemperature - MinTemperature&lt;/li&gt;&#xA;&lt;li&gt;(MaxTemperature + MinTemperature)/2&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="27736" LastEditorUserId="2470" LastEditDate="2022-10-05T17:35:59.583" LastActivityDate="2022-10-14T09:37:47.347" Title="What other statistics can I calculate with the weather statistics I already have?" Tags="|meteorology|weather-forecasting|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24397" PostTypeId="2" ParentId="3041" CreationDate="2022-10-07T16:23:04.210" Score="-1" Body="&lt;p&gt;I published some research results on the anthropogenic heat's impact on the warming, it seems the waste heat is the dominating contributor of the warming we have seen so far, it increased the temperature of surface air, land surface and ocean surface and simultaneously raise the sea level, providing strong scientific support from thermodynamic point view.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Global Warming Thermodynamics, &lt;a href=&quot;https://www.scirp.org/(S(351jmbntvnsjt1aadkposzje))/journal/paperinformation.aspx?paperid=118741&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.scirp.org/(S(351jmbntvnsjt1aadkposzje))/journal/paperinformation.aspx?paperid=118741&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;Waste heat: the dominating root cause of current global warming, &lt;a href=&quot;https://environmentalsystemsresearch.springeropen.com/articles/10.1186/s40068-020-00169-2&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://environmentalsystemsresearch.springeropen.com/articles/10.1186/s40068-020-00169-2&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;li&gt;The Nature of Climate Change-Equivalent Climate Change Model’s Application in Decoding the Root Cause of Global Warming. International Journal of Environment and Climate Change, 9, 801-822. &lt;a href=&quot;https://doi.org/10.9734/ijecc/2019/v9i1230160&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.9734/ijecc/2019/v9i1230160&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="27759" LastActivityDate="2022-10-07T16:23:04.210" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24398" PostTypeId="1" CreationDate="2022-10-07T23:35:03.450" Score="6" ViewCount="99" Body="&lt;p&gt;Wikipedia's &lt;a href=&quot;https://en.wikipedia.org/wiki/Asbestos&quot; rel=&quot;noreferrer&quot;&gt;Asbestos&lt;/a&gt; begins:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Asbestos&lt;/strong&gt; (/æsˈbɛstɒs, æz-, -təs/) is a naturally occurring fibrous silicate mineral. There are six types, all of which are composed of long and thin fibrous crystals, each fibre being composed of many microscopic &amp;quot;fibrils&amp;quot; that can be released into the atmosphere by abrasion and other processes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;As you can see, by the second sentence the article already begins to diverge from a description of the mineral itself to a discussion of its implications for humans; we are responsible for the &amp;quot;abrasion and other processes&amp;quot; and we are the ones affected by the &amp;quot;many microscopic 'fibrils' that can be released into the atmosphere&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;I'd like to understand the mechanism that results in asbestos structure of fibers and their fibrils from a crystallographic point of view.&lt;/p&gt;&#xA;&lt;p&gt;I see these questions as so interrelated that they should be answerable together likely from a single source:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;How do these crystals grow; is there some chemical reason for this extremely high anisotropy in growth rate? They are &lt;em&gt;centimeters long and microns wide&lt;/em&gt;.&lt;/li&gt;&#xA;&lt;li&gt;What keeps all the fibers and their fibrils from getting stuck together despite the pressures and temperatures necessary for formation?&lt;/li&gt;&#xA;&lt;li&gt;Why the hierarchical structure of fibers composed of fibrils? Does this have a chemical or crystallographic basis or is it just &amp;quot;the way the cookie crumbles&amp;quot; when disassembled?&lt;/li&gt;&#xA;&lt;li&gt;What ARE the pressures and temperatures necessary for formation?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Yes, &amp;quot;(t)here are six types&amp;quot; of asbestos, but I have a hunch they share the same underlying mechanism producing these fibers and their fibrils.&lt;/p&gt;&#xA;" OwnerUserId="6031" LastActivityDate="2022-11-12T01:53:00.273" Title="Why does asbestos grow in a hierarchy of separable fibers of separable fibrils; why don't they stick to each other or grow into each other?" Tags="|mineralogy|minerals|crystallography|crystals|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="24399" PostTypeId="1" AcceptedAnswerId="24400" CreationDate="2022-10-08T09:45:52.957" Score="4" ViewCount="179" Body="&lt;p&gt;Imagine a couple of people are at the side of a huge volcano, halfway to the summit, when it erupts. There's an opening to the Chambers right beside them.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Fire belched from its riven summit. The skies burst into thunder seared with lightning. Down like lashing whips fell a torrent of black rain.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;All about it the earth gaped, and from deep rifts and pits smoke and fumes leaped up. Behind them the Mountain was convulsed. Great rents opened in its side. Slow rivers of fire came down the long slopes towards them. Soon they would be engulfed. A rain of hot ash was falling.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Given the description, does it necessarily mean deadly inescapable pyroclastic flow follows?&lt;/p&gt;&#xA;&lt;p&gt;Can they survive the initial outburst, and stay alive until maybe hours later til rescue comes?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;In case it's not obvious, I'm describing the situation J.R.R.Tolkien's protagonists were in. I want to know if it's still possible for Frodo and Sam to survive a real eruption.&lt;/p&gt;&#xA;" OwnerUserId="27761" LastEditorUserId="27761" LastEditDate="2022-10-08T10:13:26.003" LastActivityDate="2022-10-10T13:30:31.443" Title="Can people on the side of a volcano survive the eruption?" Tags="|volcanology|volcanic-eruption|pyroclastic-flows|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24400" PostTypeId="2" ParentId="24399" CreationDate="2022-10-08T12:31:28.827" Score="9" Body="&lt;p&gt;It's always hard to interpret the intentions of an author. But to me, &amp;quot;a rain of hot ash&amp;quot; does not sound like a pyroclastic flow, but rather like a &lt;strong&gt;tephra fall&lt;/strong&gt;, which is a different volcanic hazard. &amp;quot;Slow rivers of fire&amp;quot; seems more obvious and probably refers to &lt;strong&gt;lava flows&lt;/strong&gt;. &amp;quot;Smoke and fumes&amp;quot; can be interpreted as &lt;strong&gt;volcanic gas&lt;/strong&gt;. So this eruption seems to present at least three of the main volcanic hazards. For a full list of volcanic hazards, see for instance &lt;a href=&quot;https://www.usgs.gov/media/images/geologic-hazards-volcanoes-download-full-poster-click-here&quot; rel=&quot;noreferrer&quot;&gt;this USGS poster&lt;/a&gt; (public domain):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/41OCa.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/41OCa.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Compared to other volcanic hazards, tephra falls, lava flows and volcanic gases rarely kill. See for instance &lt;em&gt;Volcanic disasters and incidents: A new database&lt;/em&gt; (&lt;a href=&quot;https://doi.org/10.1016/j.jvolgeores.2005.04.017&quot; rel=&quot;noreferrer&quot;&gt;Witham, 2005&lt;/a&gt;). There is a compilation of 278,341 volcano-related deaths from the year 1600, sorted by volcanic hazards (Table 15). Here is an excerpt:&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th style=&quot;text-align: left;&quot;&gt;Hazard&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Deaths&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;%&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: left;&quot;&gt;Lava&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;1564&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;0.56&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: left;&quot;&gt;Tephra/ballistic&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;13 981&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;5.02&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: left;&quot;&gt;Gases and acid rains&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;2018&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;0.73&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;&#xA;&lt;p&gt;&lt;strong&gt;Lava flows&lt;/strong&gt; rarely kills because they are slow. There are some cases of fast lava, which have been deadly, like the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Nyiragongo#1977_eruption&quot; rel=&quot;noreferrer&quot;&gt;1977 eruption of Mount Nyiragongo&lt;/a&gt;. But Tolkien said the rivers of fire were &amp;quot;slow&amp;quot;, so we can rule out this hazard as potentially lethal for the protagonists.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Tephra falls&lt;/strong&gt; mostly kill by roof collapse: when a thick layer of tephra accumulate on a roof, it will eventually collapse, killing the people inside. This is what killed most victims during the &lt;a href=&quot;https://en.wikipedia.org/wiki/1991_eruption_of_Mount_Pinatubo#Death_toll&quot; rel=&quot;noreferrer&quot;&gt;1991 eruption of Mount Pinatubo&lt;/a&gt;. So, as long as the protagonists stay outside, they should also be safe from this hazard.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Volcanic gases&lt;/strong&gt; rarely kill. Most of the deaths listed in this database are the 1746 victims of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Nyos_disaster&quot; rel=&quot;noreferrer&quot;&gt;Lake Nyos disaster&lt;/a&gt;. Other than this exceptional event, you'd have to stay very close to the gas source to get asphyxiated.&lt;/p&gt;&#xA;&lt;p&gt;So, what are the hazards that do kill lots of people? Here is the top 4:&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th style=&quot;text-align: left;&quot;&gt;Hazard&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Deaths&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;%&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: left;&quot;&gt;Disease, starvation etc&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;97 330&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;34.97&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: left;&quot;&gt;Pyroclastic flows/debris avalanches&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;63 877&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;22.95&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: left;&quot;&gt;Tsunami&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;44 610&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;16.03&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: left;&quot;&gt;Lahar/jokulhlaups&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;39 042&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;14.03&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;&#xA;&lt;p&gt;Let's skip the first one, as it is considered as an indirect hazard and needs time to be &amp;quot;efficient&amp;quot;. That leaves three hazards that could kill the protagonists: pyroclastic flows, tsunamis and lahars. In the passage you quoted, nothing evokes the first two. The &amp;quot;torrent of black rain&amp;quot;, on the other hand, could very well trigger a lahar. &lt;strong&gt;Lahars&lt;/strong&gt; tends to be confined to valleys (as shown on the USGS diagram), so the protagonists would be at risk of dying if they were running in a valley.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Pyroclastic flows&lt;/strong&gt; do not necessarily occur; they occur only if part of the ash plume collapses. But even in that case, it does not have a 360° impact. For instance, this map shows the area impacted by the pyroclastic flow (black outline) that killed ~28,000 people during the &lt;a href=&quot;https://en.wikipedia.org/wiki/1902_eruption_of_Mount_Pel%C3%A9e&quot; rel=&quot;noreferrer&quot;&gt;1902 eruption of Mount Pelee&lt;/a&gt; (Alfred Lacroix, public domain):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KvSoE.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KvSoE.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The impacted area covers only ~50° to the SW of the volcano. If the protagonists were anywhere outside this area, they would have been perfectly safe. People in towns outside this outline, like Le Morne-Rouge, actually survived (only to be killed later that year during subsequent volcanic activity, but that's another story).&lt;/p&gt;&#xA;&lt;p&gt;In summary, even if a &amp;quot;deadly inescapable pyroclastic flow&amp;quot; follows (which is not granted given the description), the protagonists would have a chance to survive if they were on the &amp;quot;good&amp;quot; side of the volcano!&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2022-10-10T13:30:31.443" LastActivityDate="2022-10-10T13:30:31.443" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24401" PostTypeId="1" CreationDate="2022-10-08T20:47:04.130" Score="2" ViewCount="25" Body="&lt;p&gt;Q1 - I'm looking for research on paleo-sea level on the Ionian basin. I'm looking for sources that take into account tectonics.&lt;/p&gt;&#xA;&lt;p&gt;Time period: Holocene - 30ka (and if possible, as far as 100ka).&lt;/p&gt;&#xA;&lt;p&gt;I've found:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Vott (2007) (DOI: 10.1016/j.quascirev.2007.01.004)&lt;/li&gt;&#xA;&lt;li&gt;Ferentinos (2012) (DOI: 10.1016/j.jas.2012.01.032)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Vott deals with the Pelopennese &amp;amp; Akarnania. I'm specifically looking for research on the Ionian islands. He does include include tectonics and shows that RSL varies regionally due to tectonics.&lt;/p&gt;&#xA;&lt;p&gt;Ferentinos deals with the Ionian islands, but does not take tectonics into account.&lt;/p&gt;&#xA;&lt;p&gt;Q2 - I've also been looking for a sea level curve but the closest I've gotten is the Adriatic sea.&lt;/p&gt;&#xA;&lt;p&gt;Time period: same&lt;/p&gt;&#xA;" OwnerUserId="27637" LastActivityDate="2022-10-08T20:47:04.130" Title="Paleo-sea level of the Ionian basin" Tags="|sea-level|paleogeography|isostasy|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24403" PostTypeId="1" CreationDate="2022-10-09T16:46:02.670" Score="1" ViewCount="55" Body="&lt;p&gt;I am doing some preliminary research on aeolian/nival landforms in Andes and I came across this:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/G9ydb.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G9ydb.png&quot; alt=&quot;bright polygonish nets&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;located at &lt;a href=&quot;https://www.google.com/maps/place/24%C2%B057%2703.4%22S+68%C2%B016%2706.7%22W/@-24.950958,-68.2688391,1090m/data=!3m1!1e3!4m5!3m4!1s0x0:0x6698177a50c86e8!8m2!3d-24.9509483!4d-68.268528&quot; rel=&quot;nofollow noreferrer&quot;&gt;-24.950948, -68.268528&lt;/a&gt; and other locations throughout the Argentinian Dry Andes. Any idea what could these landforms be?&lt;/p&gt;&#xA;&lt;p&gt;Thanks!&#xA;V.&lt;/p&gt;&#xA;" OwnerUserId="27768" LastEditorUserId="18081" LastEditDate="2022-10-10T07:59:22.067" LastActivityDate="2022-10-10T07:59:22.067" Title="Bright patterns in the Dry Andes" Tags="|geomorphology|satellite-oddities|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24404" PostTypeId="2" ParentId="24403" CreationDate="2022-10-09T19:49:01.490" Score="1" Body="&lt;p&gt;It could be some kind of shallow-rooted grasses. A little to the south those features appear to separate into different colors. Though I think this unlikely because your location is in a concave part of the landscape...so unstable for vegetation.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/2pEQj.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2pEQj.png&quot; alt=&quot;change in color further south&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27637" LastEditorUserId="2470" LastEditDate="2022-10-10T02:44:57.737" LastActivityDate="2022-10-10T02:44:57.737" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24405" PostTypeId="2" ParentId="18986" CreationDate="2022-10-10T09:06:32.523" Score="-4" Body="&lt;p&gt;The atmosphere has heated about .5 C since 1979. It takes 3 Zeta Joules of energy to accomplish that. That would be .075 ZJ per year if purely cumulative. Residual heat from human energy consumption amounts to .5 ZJ per year or about 20 ZJ since 1979. That is 7 times what would be needed to heat the atmosphere by .5 C. (We note that the oceans are accumulating thermal energy too). In addition to direct transfer of black body radiation to space, molecular collision induced IR generation in the upper atmosphere is where cooling of the global energy reservoir establishes equilibrium. Waste heat energy added to the climate system (with an overprint of natural fluctuation) is the primary cause of the slight increase in temperature of the atmosphere since 1979. But sceptics and alarmists alike tend to ignore waste heat as a serious contributor to climate change.&lt;/p&gt;&#xA;" OwnerUserId="27771" LastActivityDate="2022-10-10T09:06:32.523" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24406" PostTypeId="1" CreationDate="2022-10-11T15:08:12.693" Score="3" ViewCount="85" Body="&lt;p&gt;I wondered, in general, what has happened to all the minerals that have been mined by humans. Do they still circulate in the economy and could be recovered through 'urban mining'. Or will they have corroded or otherwise reacted with the environment and no longer exist in a form that could be easily recovered?&lt;/p&gt;&#xA;&lt;p&gt;I appreciate it's a broad question. I might be helpful to discuss a single mineral as an example.&lt;/p&gt;&#xA;" OwnerUserId="27776" LastActivityDate="2022-10-11T18:03:07.730" Title="Where are all the minerals that have been mined?" Tags="|minerals|mining|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24407" PostTypeId="1" CreationDate="2022-10-11T17:47:03.327" Score="1" ViewCount="56" Body="&lt;p&gt;I noticed that the Middle East's rainy season generally runs from &lt;a href=&quot;https://weatherspark.com/y/104018/Average-Weather-in-Riyadh-Saudi-Arabia-Year-Round#Sections-Rain&quot; rel=&quot;nofollow noreferrer&quot;&gt;November to May&lt;/a&gt;; but Florida, which is at almost the same latitude, is exactly the opposite, peaking from &lt;a href=&quot;https://weatherspark.com/y/18622/Average-Weather-in-Miami-Florida-United-States-Year-Round#Sections-Rain&quot; rel=&quot;nofollow noreferrer&quot;&gt;May to November&lt;/a&gt;.  Can anyone provide a rationale as to why?&lt;/p&gt;&#xA;&lt;p&gt;Thanks.&lt;/p&gt;&#xA;" OwnerUserId="27777" LastEditorUserId="6298" LastEditDate="2022-10-11T21:55:24.837" LastActivityDate="2022-10-11T21:55:24.837" Title="Why are rainy seasons different in different locations?" Tags="|meteorology|climate|" AnswerCount="0" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="24408" PostTypeId="2" ParentId="24406" CreationDate="2022-10-11T18:03:07.730" Score="4" Body="&lt;p&gt;The answer is, &amp;quot;it depends on the minerals and what happened to them once they were mined&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;There are two types of minerals mined: ore minerals and waste minerals. To mine ore minerals invariably waste minerals must also be mined. Waste minerals typically encapsulate orebodies. To mine the ore, some of the waste must be mined as well. For  reasons of safety, stability and practicality, the walls of open pit mines cannot be vertical. They have to be sloped. Because of that, some waste must be mined to get access to the ore.&lt;/p&gt;&#xA;&lt;p&gt;Similarly with underground mining, not all the tunnels will be mined in ore. To access the ore, some tunneling will be done in waste.&lt;/p&gt;&#xA;&lt;p&gt;Depending on the geology of the deposit, most waste minerals will be silicates, such as the minerals within basalt, etc. The waste rock will either be dumped onto a waste dump on the surface and very slowly oxidize over time, or they will be used to backfill stopes, underground, that once contained ore minerals. In vary rare instances some of the minerals will be used as road construction materials.&#xA;As for ore minerals they must first be processed to concentrate the ore minerals. The associated waste minerals from the processing plant usually end up in a tailing dam and will slowly oxidize over time. In more recent times, at some mines, some of the minerals that are larger than 200 μm in size have been returned as paste fill to the voids from which ore minerals were extracted.&lt;/p&gt;&#xA;&lt;p&gt;There are basically two types of ore minerals: oxides and sulfides. From these, the metals of interest will be extracted: iron, zinc, copper, tin, lead etc. In the past, the unwanted sulfide minerals may have been converted to sulfur dioxide and released into the atmosphere. Some of it may have been used to make sulfuric acid. Some of it has been dumped and is slowly oxidizing and forming sulfuric acid in the environment, to the detriment of the environment.&lt;/p&gt;&#xA;&lt;p&gt;In the past, some sulfide ores have been &lt;a href=&quot;https://www.merriam-webster.com/dictionary/pyritic%20smelting&quot; rel=&quot;nofollow noreferrer&quot;&gt;burned as a fuel&lt;/a&gt; to rapidly oxidize the minerals to make downstream extraction of the desired metal easier. Such burning produced vast quantities of sulfur dioxide which  produced acid rain, which then kill the surrounding vegetation resulting in a denuded and much damaged landscape.&lt;/p&gt;&#xA;&lt;p&gt;Eventually, most metals that have been extracted from minerals will oxidize over time.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-10-11T18:03:07.730" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24409" PostTypeId="1" CreationDate="2022-10-12T11:00:13.780" Score="4" ViewCount="79" Body="&lt;p&gt;While performing petrographic analysis in a rock composed mainly of plagioclase, pyroxene and olivine, I came across the mineral shown in the photo. Do you have any clues of what it could be?&lt;/p&gt;&#xA;&lt;p&gt;The images of the rock in thin sections were taken with a polarising microscope. The top photo is the image with the crossed polarizers and the bottom photo is the image with one polarizer.&lt;/p&gt;&#xA;&lt;p&gt;The biggest mineral (shown in photos) is about 800μm but there are also smaller ones.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oVo1z.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oVo1z.jpg&quot; alt=&quot;XPL&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8bjOo.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8bjOo.jpg&quot; alt=&quot;1PL&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27779" LastEditorUserId="6298" LastEditDate="2022-10-13T16:49:44.800" LastActivityDate="2022-10-13T16:49:44.800" Title="Help with petrographic analysis of a complex mineral" Tags="|geology|minerals|petrography|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24410" PostTypeId="1" CreationDate="2022-10-12T19:27:18.083" Score="1" ViewCount="28" Body="&lt;p&gt;According to &lt;a href=&quot;https://en.wikipedia.org/wiki/Aral_Sea#North_Aral_Sea_restoration_work&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;, the North Aral Sea is being partially restored, by restoring some of the Syr Darya river's flow (which was diverted by the Soviet Union for irrigation), and by building &lt;a href=&quot;https://en.wikipedia.org/wiki/Dike_Kokaral&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dike Kokaral&lt;/a&gt; to keep water in the North Aral Sea instead of flowing to the south.&lt;/p&gt;&#xA;&lt;p&gt;Looking through images on Google, you can see that Dike Kokaral still at least occasionally lets water through, which made me wonder as to whether the South Aral Sea was receiving as much water as before the dam, thanks to the improved flow of Syr Darya.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;What is the yearly discharge of the dam?&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;What was the yearly discharge of the Sy Darya river before irrigation works were repaired and improved?&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.worldbank.org/en/results/2005/09/01/saving-a-corner-of-the-aral-sea&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YJzRn.png&quot; alt=&quot;Dike Kokaral letting water through&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="14561" LastActivityDate="2022-10-12T19:27:18.083" Title="How does the water passing Dike Kokaral compare to the discharge of the Syr Darya river before its water flow was improved?" Tags="|rivers|lakes|dams|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24411" PostTypeId="2" ParentId="24409" CreationDate="2022-10-13T02:32:19.037" Score="2" Body="&lt;p&gt;It would help to be able to see photos with the stage at different points of rotation. However, this looks like a mafic volcanic rock with olivine being replaced by iddingsite in the top left; so there has been some post-crystallization alteration.&lt;/p&gt;&#xA;&lt;p&gt;Two ideas: it may just be an altered phenocryst that has been replaced by a fine-grained clay mineral; or (and more likely in my opinion), it may be a piece of devitrified glass - the radial fibrous texture in XPL resembles a spherulite, which is a common devitrification texture. In felsic igneous rocks these are commonly composed of quartz and K-feldspar; I do not know what the equivalent constituents would be in a mafic rock.&lt;/p&gt;&#xA;" OwnerUserId="27389" LastActivityDate="2022-10-13T02:32:19.037" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24412" PostTypeId="1" CreationDate="2022-10-13T10:04:27.353" Score="6" ViewCount="812" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Steptoe_Butte&quot; rel=&quot;nofollow noreferrer&quot;&gt;Steptoe Butte&lt;/a&gt; is a quartzite &amp;quot;island&amp;quot; in the sea of loess known as the Palouse Hills, in eastern Washington and western Idaho in the United States. According to Wikipedia:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The rock that forms the butte is over 400 million years old&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;with no source to this claim. Looking around, I found &lt;a href=&quot;https://wa100.dnr.wa.gov/columbia-basin/steptoe-butte&quot; rel=&quot;nofollow noreferrer&quot;&gt;this page&lt;/a&gt; from the Washington Geological Survey, which claims that Steptoe Butte is part of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Belt_Supergroup&quot; rel=&quot;nofollow noreferrer&quot;&gt;Belt Supergroup&lt;/a&gt;, with an age of 1.4&lt;span class=&quot;math-container&quot;&gt;$-$&lt;/span&gt;1.5 Ga. Similar information and age can also be found on &lt;a href=&quot;https://webpages.uidaho.edu/geolsci/geology101/STOP1.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this University of Idaho webpage&lt;/a&gt;. Now comes &lt;a href=&quot;https://floodexplorer.org/items/show/87&quot; rel=&quot;nofollow noreferrer&quot;&gt;this Eastern Washington University page&lt;/a&gt;, which claims (emphasis mine):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The butte of quartzite is &lt;em&gt;well over 400 million years old&lt;/em&gt;, metamorphosed from a protolith of sandstone that went under searing temperatures and pressure into a hardy metamorphic rock known as quartzite which is almost entirely made of interlocking grains of quartz and other minerals (see photos of quartzite). On the northern lower part of the miraculous summit, it has vitreous quartzite with feldspathic matrix &lt;em&gt;that was initially interpreted as Precambrian Belt Supergroup&lt;/em&gt; (Waggoner, 1998 and the attached geologic map). But, using the age distribution of detrital zircons resulted in a dominant age peak of 1.7 to 1.9 billion years old (Ellis et al., 2004), which correlates with the age peak of detrital zircons from the Cambrian period (e.g. Ross and Villeneuve, 2003; Linde et al, 2017). &lt;em&gt;This information means that the quartzite is not as old as it was once thought to be, but is still quite old&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I can't make sense of this last passage. The cited &lt;a href=&quot;https://gsa.confex.com/gsa/2004RM/webprogram/Paper72909.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;abstract (Ellis et al., 2004)&lt;/a&gt; goes:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The youngest grains observed constitute a dominant age peak at approximately 1.7-1.9 Ga. Older minor peaks occur at 2.45, 2.6-2.7, 2.9 and 3.3 Ga. Despite the apparent difference in degree of deformation, quartzites on Steptoe and Kamiak Buttes are likely correlative. The detrital zircon signatures are consistent with those determined for easterly derived units of the Belt-Purcell Supergroup which contain a strong Laurentian signature (Ross and Villeneuve, 2003), but lack the younger 1.45-1.5 Ga syn-depositional detrital zircon signature that characterizes some sections of the Belt-Purcell sequence such as the nearby Wallace Formation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;But I don't see how this tells us that Steptoe Butte is not part of the Belt Supergroup and is thus of Cambrian age, as the previous text implies. So, I'd like to ask: &lt;strong&gt;how old is Steptoe Butte?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2022-10-15T11:40:50.500" LastActivityDate="2022-10-15T11:40:50.500" Title="How old is Steptoe Butte (WA, USA)?" Tags="|stratigraphy|geochronology|regional-geology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24413" PostTypeId="2" ParentId="24412" CreationDate="2022-10-13T12:42:51.853" Score="9" Body="&lt;p&gt;Without directly knowing anything about WA geology myself, you're dealing with two ages here: the age the rock deposited as a sandstone (protolith age, 1.4-1.5 Ga), and the age of metamorphism (400 Ma).&lt;/p&gt;&#xA;&lt;p&gt;Detrital zircon populations constrain the depositional age because the U-Pb system in zircon stays robust below 900 °C. These are transported from their original host rock via fluvial systems and other sedimentological processes. Eventually you get a rock (in this case a sandstone) with a pastiche of &lt;em&gt;necessarily older&lt;/em&gt; detrital zircons that can give you a minimum depositional age. I am not sure why it is considered 200-300 million years younger than its oldest zircon population; it is possible there is simply known sedimentation at 1.4-1.5 Ga.&lt;/p&gt;&#xA;&lt;p&gt;Thereafter, it was metamorphosed from a sandstone to a quartzite at 400 Ma, likely during the assembly of Pangaea going by the age.&lt;/p&gt;&#xA;" OwnerUserId="27389" LastEditorUserId="27389" LastEditDate="2022-10-14T12:52:41.260" LastActivityDate="2022-10-14T12:52:41.260" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24415" PostTypeId="2" ParentId="24396" CreationDate="2022-10-14T09:37:47.347" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;but the weather statistics I have don't correlate as much as I would like&#xA;Blockquote&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;That sounds like you are trying to find evidence that suits your hypothesis, in stead of basing your conclusion on the data. If there is no correlation between the two, no matter which statistic you will throw at it will prove that there is one.&lt;/p&gt;&#xA;&lt;p&gt;That being said, you can always get fancy with metrics like precipitation / temperature and all sorts of variations. I advice against this.&lt;/p&gt;&#xA;" OwnerUserId="27794" LastActivityDate="2022-10-14T09:37:47.347" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24416" PostTypeId="1" CreationDate="2022-10-14T12:27:57.963" Score="2" ViewCount="47" Body="&lt;p&gt;I noticed that inside an enclosed farm, there were multiple structures erected. They looked like 2 wooden poles/sticks with circular net around it. I wanted to know what’s the name for it and what’s the purpose behind erecting it?&lt;/p&gt;&#xA;" OwnerUserId="27795" LastActivityDate="2022-10-14T12:27:57.963" Title="What is the name &amp; purpose of 2 wooden poles with a net around it in a farm?" Tags="|agriculture|" AnswerCount="0" CommentCount="1" ClosedDate="2022-10-14T23:19:57.983" ContentLicense="CC BY-SA 4.0" />
  <row Id="24417" PostTypeId="1" CreationDate="2022-10-16T15:26:46.417" Score="11" ViewCount="237" Body="&lt;p&gt;What exactly was it in the ancient Martian atmosphere that made it red? Was it water, molecular oxygen or something else?&lt;/p&gt;&#xA;" OwnerUserId="27711" LastEditorDisplayName="user28185" LastEditDate="2023-01-20T12:55:13.163" LastActivityDate="2023-03-11T16:22:03.977" Title="What oxidised the soil on Mars?" Tags="|geochemistry|planetary-science|mars|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24419" PostTypeId="1" CreationDate="2022-10-16T16:08:28.230" Score="2" ViewCount="183" Body="&lt;p&gt;I do not understand why the fact that warm air is above cold air causes a lid like effect and traps pollutants below? What is it about that order? Why does warm air below cold air not restrict any pollutants from rising and dispersing in the atmosphere?&lt;/p&gt;&#xA;&lt;p&gt;I am not asking what causes them, but why they have the effect that they do.&lt;/p&gt;&#xA;" OwnerUserId="27803" LastActivityDate="2022-12-01T18:07:15.837" Title="Why does a temperature inversion act like a lid?" Tags="|temperature|air-pollution|inversion|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24421" PostTypeId="1" CreationDate="2022-10-16T21:16:52.830" Score="4" ViewCount="156" Body="&lt;p&gt;I am interested in the native landscape of the UK before humans starting ploughing the earth, introducing livestock and deforesting.&lt;/p&gt;&#xA;&lt;p&gt;What would someone see walking from say the location of Cambridge eastwards out towards the coast to Southwold?&lt;/p&gt;&#xA;&lt;p&gt;Would it simply be one vast forest or more sparsely forested with areas of grassland?&lt;/p&gt;&#xA;&lt;p&gt;I am aware that before the draining of the fens there were vast marshes to the North West of the Region.&lt;/p&gt;&#xA;" OwnerUserId="27805" LastActivityDate="2023-12-14T12:01:35.283" Title="What would East Anglia look like without the presence of humans today?" Tags="|earth-history|agriculture|deforestation|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24422" PostTypeId="2" ParentId="23908" CreationDate="2022-10-17T03:34:27.697" Score="3" Body="&lt;p&gt;The index of refraction for air &lt;a href=&quot;https://en.wikipedia.org/wiki/Refractive_index#Density&quot; rel=&quot;nofollow noreferrer&quot;&gt;scales linearly with density&lt;/a&gt;, and the density in an idea gas is proportional to pressure and inversely proportional to temperature. Under typical atmospheric conditions, dry air is reasonably ideal, so we can write:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$n_{1} = n - 1 = \frac{(n_0-1) T_0}{P_0}\frac{P}{T}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$n_0$&lt;/span&gt; is the index of refraction at some reference temperature &lt;span class=&quot;math-container&quot;&gt;$T_0$&lt;/span&gt; and pressure &lt;span class=&quot;math-container&quot;&gt;$P_0$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://archive.org/details/jresv50n1p39/mode/2up&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;'The Constants in the Equation for Atmospheric Refractive Index at Radio Frequencies', Journal of Research of the Notional Bureau of Standards Vol. 50, No.1, January 1953 Research Paper 2385&quot;&gt;Smith and Weintraub&lt;/a&gt; used a value of &lt;span class=&quot;math-container&quot;&gt;$n_0-1 = 288.04\times10^{-6}$&lt;/span&gt; which was the average of 3 published values for visible, 9 GHz, and 24 GHz electromagnetic radiation measured at &lt;span class=&quot;math-container&quot;&gt;$T_0 = 273\,\textrm{K}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$P_0 = 1013.15\,\textrm{mb}$&lt;/span&gt;, which gives&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$n_{1} = n - 1 = 77.6\times 10^{-6} \frac{P}{T}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;(I figured this out while wrestling with a similar commonly-used but obscurely-sourced equation relevant to my own question &lt;a href=&quot;https://physics.stackexchange.com/questions/732028/how-distant-is-the-horizon-on-venus&quot;&gt;&amp;quot;How distant is the horizon on Venus?&amp;quot;&lt;/a&gt;.)&lt;/p&gt;&#xA;" OwnerUserId="27775" LastActivityDate="2022-10-17T03:34:27.697" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24425" PostTypeId="1" CreationDate="2022-10-17T12:53:43.333" Score="3" ViewCount="22" Body="&lt;p&gt;As we know that Indian monsoon basically involves a low pressure area over Tibet Plateau and a high pressure area near Mascarene basin. How come Positive Indian ocean dipole enhances the monsoon as it involves warm water accumulation near western Indian ocean which would create a low pressure area near Madagascar?&lt;/p&gt;&#xA;" OwnerUserId="27810" LastActivityDate="2022-10-17T12:53:43.333" Title="Relationship between Indian monsoon and Indian ocean Dipole" Tags="|geography|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24426" PostTypeId="1" CreationDate="2022-10-18T03:44:48.397" Score="1" ViewCount="104" Body="&lt;p&gt;Is there any simple experiment which can be done to show empirical evidence that carbon dioxide causes the greenhouse effect?&lt;/p&gt;&#xA;&lt;p&gt;I'm imagining something simple like two sealed fish tanks, one filled with air that we breath every day, and the other filled with the same air but with a 50% higher concentration of carbon dioxide. Shine a light into them both and measure the temperature.&lt;/p&gt;&#xA;&lt;p&gt;I think this would convert a lot of &amp;quot;deniers&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="27814" LastEditorUserId="7741" LastEditDate="2022-10-18T19:08:58.177" LastActivityDate="2022-10-18T19:08:58.177" Title="How to demonstrate the warming effect of CO2 at home?" Tags="|climate-change|atmosphere|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24427" PostTypeId="1" CreationDate="2022-10-18T08:01:39.027" Score="4" ViewCount="66" Body="&lt;p&gt;We can use the aridity index &lt;span class=&quot;math-container&quot;&gt;$\left ( ai = \dfrac{P}{PET} \right )$&lt;/span&gt; to define arid areas. Hyperarid areas have &lt;span class=&quot;math-container&quot;&gt;$ai &amp;lt; 0.05$&lt;/span&gt;. Is there a similar threshold for hyper-humid regions?&lt;/p&gt;&#xA;&lt;p&gt;Would it be 20 (inverse of the threshold for hyperarid)?&lt;/p&gt;&#xA;" OwnerUserId="21719" LastEditorUserId="6" LastEditDate="2022-11-01T09:40:24.277" LastActivityDate="2022-11-01T09:40:24.277" Title="What is the definition for a hyper-humid area?" Tags="|climate|humidity|evapotranspiration|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24428" PostTypeId="2" ParentId="24387" CreationDate="2022-10-18T09:53:25.590" Score="1" Body="&lt;p&gt;From your question you are obviously aware that gas deposit arise from life forms sinking to the bottom of shallow seas when they die, they accumulate over time and are subsequently covered by marine geological sediments.&lt;/p&gt;&#xA;&lt;p&gt;Over time the thickness of the sediments increases. As the &lt;a href=&quot;https://www.planete-energies.com/en/medias/close/how-oil-and-gas-deposits-are-formed&quot; rel=&quot;nofollow noreferrer&quot;&gt;sediment&lt;/a&gt; thickness increases,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The weight of accumulating sediment very slowly pushes the source rock further under the Earth's crust, by a few meters to a few hundred meters every million years or so. This gradual sinking is called subsidence and leads to the formation of sedimentary basins.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I would qualify the above quotation in the source rock is pushed further &lt;strong&gt;into&lt;/strong&gt; the Earth's crust, not &lt;em&gt;under&lt;/em&gt; the Earth's crust, as pushing under the Earth's crust can suggest it gets pushed in the the Mantle or the contact region between the Mantle and the Crust.&lt;/p&gt;&#xA;&lt;p&gt;The surface of the Earth is not static, it constantly moves, via a process called &lt;a href=&quot;https://en.wikipedia.org/wiki/Plate_tectonics&quot; rel=&quot;nofollow noreferrer&quot;&gt;plate tectonics&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, different types of rock have differing degrees of flexibility and rigidity. Under various ground stresses rocks will fracture and faults and other discontinuities arise. Under certain situations the alignment of such faults can produce &lt;a href=&quot;https://en.wikipedia.org/wiki/Graben&quot; rel=&quot;nofollow noreferrer&quot;&gt;graben&lt;/a&gt; and horst structures. Horst structures rise while graben structures sink, mainly due to gravity.&lt;/p&gt;&#xA;&lt;p&gt;Over time, sediments can fill graben structure and over the course of millions of years the original deposit of life forms ends up being buried deeply. At depth, the remains of the life forms are &amp;quot;pressure cooked&amp;quot; - subject to high temperatures and pressures - producing natural gas.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-10-18T09:53:25.590" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24429" PostTypeId="2" ParentId="24426" CreationDate="2022-10-18T14:30:44.997" Score="3" Body="&lt;p&gt;&lt;a href=&quot;https://royalsocietypublishing.org/doi/10.1098/rsos.192075#d2380104e1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Levendis et al&lt;/a&gt; designed a simple experiment with balloons filled with air or air and CO2. They measured how long it took to cool a heated element in the two environments. It's by no means a perfect analogy, but given the well understood physics of CO2 it's hardly necessary to experiment at this scale.  Many school science resource sites will give instructions for simple 'bottle' experiments that demonstrate the IR absorption of CO2 on the lab bench.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2022-10-18T14:30:44.997" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24430" PostTypeId="1" CreationDate="2022-10-18T21:13:48.807" Score="4" ViewCount="85" Body="&lt;p&gt;Visiting from WorldBuilding SE. Someone recently asked a question that dusted off an old theory I had once had, so I started digging. Sadly I could find little more on the topic than the first time I had the thought so I am coming here.&lt;/p&gt;&#xA;&lt;p&gt;I remember learning about plate tectonics in school, books, TV, magazine articles, etc. All mention the &lt;em&gt;origin&lt;/em&gt; of the continents was quietly skipped. If it were mentioned at all it was just noted as a mystery.&lt;/p&gt;&#xA;&lt;p&gt;Fast forward a few more years and I learn of another theory, about the formation of the moon. I read about the &lt;a href=&quot;https://en.wikipedia.org/wiki/Giant-impact_hypothesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;Theia Impact theory&lt;/a&gt; and saw this animation where another planetary body (Theia) impacts the Proto-Earth, forming the moon:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LzEJH.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LzEJH.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The moment I saw it I knew here was the origin of the continents. Perhaps not the crustal plates but the contents, or rather the &lt;a href=&quot;https://en.wikipedia.org/wiki/Craton&quot; rel=&quot;nofollow noreferrer&quot;&gt;cratons&lt;/a&gt; that float atop the mantle and form the continents we are familiar with.&lt;/p&gt;&#xA;&lt;p&gt;Everyone knows of Gondwana and Pangaea, supercontinents of the past. More rarely known is there may have been as many as 10 supercontinents. Ur and VaalBara being among the first, billions of years before Pangaea.&lt;/p&gt;&#xA;&lt;p&gt;Question: Have there been any publications or studies to prove my novice theory that the moon formation had something to do with the origin of the continents? I was able to find a couple references from Harvard papers, but honestly and obviously it would take a degree to decipher 90 percent of it. In which case I would be answering my own question. Even here the closest &lt;a href=&quot;https://earthscience.stackexchange.com/questions/19261/where-did-the-continents-come-from&quot;&gt;answer&lt;/a&gt; is that they formed in the early Hadean.&lt;/p&gt;&#xA;&lt;p&gt;So is this an accepted theory I just haven't ran across, or has it been considered much before?&lt;/p&gt;&#xA;" OwnerUserId="27819" LastEditorUserId="6298" LastEditDate="2022-10-19T02:15:49.223" LastActivityDate="2022-10-19T02:15:49.223" Title="Origin of the continents" Tags="|plate-tectonics|astronomy|continent|impacts|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24431" PostTypeId="2" ParentId="24430" CreationDate="2022-10-18T23:43:58.137" Score="7" Body="&lt;p&gt;The impact which created the moon occurred quite early into the Solar System's lifespan. Bodies of that size would have both still been mostly molten at the time of impact; so as far as I am aware, your theory isn't part of mainstream geologic thought, though that shouldn't discourage you from coming up with these ideas!&lt;/p&gt;&#xA;&lt;p&gt;The current widely-accepted paradigm is that the continents grew gradually over geologic time and, and only rarely are very small fragments of them 'recycled' back into the mantle. There are several other, more fringe theories that favour a static ratio of continental to oceanic crust through geologic time, arguing for a much larger fraction of continental recycling. The latter camp is arguing against quite a large body of radiometric age evidence and a good deal of correlation between those ages and processes ongoing along tectonically active continental margins.&lt;/p&gt;&#xA;&lt;p&gt;To understand why the continents came to be, you need to understand the process of 'differentiation'. In more recent geological contexts (about anything that happened post-3.7 billion years ago), differentiation explains why igneous rocks (lavas and magmas) attain their various chemical compositions: certain elements are more thermodynamically stable than others in a solid phase, while others prefer to hang out in the liquid (magma) for a lot longer. This means that certain elements are concentrated in early solids (rocks) while others are more abundant in the later formed rocks. It so happens that those in the latter group - sodium, potassium, aluminum, and (because of its abundance) silicon - tend to form much lower density minerals, and those minerals together make for lower density rocks.&lt;/p&gt;&#xA;&lt;p&gt;If you apply the concept of differentiation to a planet-spanning magma ocean - like the one on Earth in the Hadean - you concentrate the heavy elements deep in the Earth, which is why the core and mantle are rich in elements like iron, nickel, and chromium. Over time, further differentiation operating on a much smaller scale will produce low-density rocks that are too light to be shoved back into the mantle, effectively permanently stranding them near the surface - and thus creating the beginnings of a continent. Repeating this process over billions of years worth of magmatism is what is generally accepted to have led to the gradual (and more or less permanent) growth of the continents.&lt;/p&gt;&#xA;" OwnerUserId="27389" LastActivityDate="2022-10-18T23:43:58.137" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24432" PostTypeId="1" CreationDate="2022-10-19T01:45:59.383" Score="3" ViewCount="65" Body="&lt;p&gt;I know that space is big and satellites are small compared with the moon, but do they have, or will they if we get more, any effect on the sea and ocean water on the earth?&lt;/p&gt;&#xA;" OwnerUserId="24806" LastEditorUserId="18081" LastEditDate="2022-10-26T08:58:01.800" LastActivityDate="2022-10-26T08:58:01.800" Title="Do the 600 satellites that orbit the Earth have any gravitational pull on the tides like the moon?" Tags="|sea-level|tides|gravity|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24433" PostTypeId="1" CreationDate="2022-10-19T18:23:57.397" Score="2" ViewCount="119" Body="&lt;p&gt;I have spent hours on this topic and I seem unable to make sense of it.&#xA;If air moves from high pressure toward low pressure, and wind is the movement of air due to differences in pressure, how can, for example, a warm front occur? What can bring a warm air mass to overtake a cold air mass? Shouldn't just the cold air mass move toward the warm air mass, as the warm air mass has lower pressure and winds will be blowing in that direction?&lt;/p&gt;&#xA;" OwnerUserId="27824" LastActivityDate="2022-10-24T03:37:57.643" Title="Air pressure, fronts and temperature" Tags="|meteorology|weather-forecasting|atmospheric-circulation|pressure|air|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24434" PostTypeId="1" CreationDate="2022-10-20T03:53:38.633" Score="2" ViewCount="22" Body="&lt;p&gt;The case is that, if it landed at the North Pole or the South Pole, the global after-impact effects such as gases and dust spreading through the atmosphere, earthquakes, tsunamis, volcanism and massive forest fires would be minimized, could become more regional.&lt;/p&gt;&#xA;" OwnerUserId="27826" LastActivityDate="2022-10-20T03:53:38.633" Title="If the asteroid that wiped out most of the dinosaurs had impacted much closer to the poles, would the extinction event have be smaller?" Tags="|geology|paleontology|mass-extinction|asteroids|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24435" PostTypeId="1" CreationDate="2022-10-20T04:05:01.530" Score="4" ViewCount="84" Body="&lt;p&gt;China is a region rich in sedimentary rocks from the Mesozoic period and incredible discoveries about dinosaurs have been made there since the 1990s.&#xA;I was wondering which other areas of the planet might contain rich and unique fossil resources from the Mesozoic and which are still unexplored or underexplored.&lt;/p&gt;&#xA;" OwnerUserId="27827" LastActivityDate="2022-11-24T06:12:09.540" Title="What other areas of the planet might be rich in Mesozoic-era fossils that have yet to be explored?" Tags="|geology|paleontology|fossils|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24436" PostTypeId="1" CreationDate="2022-10-20T08:58:17.117" Score="2" ViewCount="25" Body="&lt;p&gt;ACRU model was running fine and producing output.&#xA;After a few runs and parameter changes, the model returns this error message &lt;a href=&quot;https://i.stack.imgur.com/eokr0.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eokr0.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;Not sure what went wrong or changed.&lt;/p&gt;&#xA;&lt;p&gt;Does anyone know what this means or how to resolve the problem?&lt;/p&gt;&#xA;" OwnerUserId="27363" LastActivityDate="2023-03-23T11:57:42.480" Title="ACRU4 model run error: climate file -&gt; &quot;Error running display and data rules&quot;" Tags="|hydrology|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24437" PostTypeId="2" ParentId="24436" CreationDate="2022-10-20T08:58:17.117" Score="1" Body="&lt;p&gt;It could be one of two issues:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Sometimes &amp;amp; likely:&lt;/strong&gt; You’ve run out of space on your computer (check your local drive for space)&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Often &amp;amp; very likely:&lt;/strong&gt; There is data in the climate file which is in the wrong place or has the wrong formatting (the solution is to recheck your climate files and run through it line by line for anything that is out of place, it’s easy to miss this in between several runs and updates to a climate file)&lt;/p&gt;&#xA;" OwnerUserId="27363" LastActivityDate="2022-10-20T08:58:17.117" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24438" PostTypeId="1" AcceptedAnswerId="24445" CreationDate="2022-10-20T10:49:54.713" Score="6" ViewCount="520" Body="&lt;p&gt;I'm working with wind data, that I buy from a company, which delivers basically reformatted ERA5 weather data from ECMWF (&lt;a href=&quot;https://www.ecmwf.int/&quot; rel=&quot;noreferrer&quot;&gt;https://www.ecmwf.int/&lt;/a&gt;). Their historic wind data includes &amp;quot;Wind gusts (sfc)&amp;quot; (m/s) and I cannot find out how this &amp;quot;Wind gust&amp;quot; is defined.&lt;/p&gt;&#xA;&lt;p&gt;My understanding is that a wind gust is basically just the maximum value of wind velocity of a number of averages within an observation period. Say I measure wind velocity as average over 1 hour, then look at the 10-minute averages of that same 1 hour and the largest of those is my &amp;quot;Wind gust&amp;quot; (V_600_3600 - see here for nomenclature: &lt;a href=&quot;http://ijsetr.com/uploads/621345IJSETR1044-354.pdf&quot; rel=&quot;noreferrer&quot;&gt;http://ijsetr.com/uploads/621345IJSETR1044-354.pdf&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;But the ERA data are a re-analysis so of course the gust is basically just a factor on top of the average 1hour wind. What I cannot figure out, is, which gust definition this uses. Is it 10-min (V_600_3600) or 1-min (V_60_3600) or even 3-seconds (V_3_3600).&lt;/p&gt;&#xA;&lt;p&gt;The support of my data-company insists that &amp;quot;Wind gust&amp;quot; is &amp;quot;the maximum wind velocity within an hour&amp;quot; (they deliver hourly data over long time periods - years) but they insist that this &amp;quot;Wind gust&amp;quot;-value cannot be defined in terms of a particular averaging-time period like 10-minute gust or similar.&lt;/p&gt;&#xA;&lt;p&gt;I tried to find the wind gust definition for ERA5 - the only thing I found is this definition here, that defines the &amp;quot;Instantaneous 10m wind gust&amp;quot; as being equal to the 3s wind gust (V_3_3600): &lt;a href=&quot;https://eqc-cms.predictia.es/pub/qar/reanalysis-1412/pdf&quot; rel=&quot;noreferrer&quot;&gt;https://eqc-cms.predictia.es/pub/qar/reanalysis-1412/pdf&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Is this the correct definition? I'm a bit confused, since this contradicts the company support guys (which are specialist for this thing). They insist, there is not time-averaging-period attached to the definition of &amp;quot;Wind gust&amp;quot; which is, in my understanding, not sensible. There &lt;em&gt;must&lt;/em&gt; be some time information attached to any definition of &amp;quot;wind gust&amp;quot; as far as I understand? But then again I'm not a meteorologist and might miss something basic.&lt;/p&gt;&#xA;&lt;p&gt;Obliged for any help to clarify this respectively lets me understand this better.&lt;/p&gt;&#xA;" OwnerUserId="27444" LastActivityDate="2022-10-21T10:05:29.780" Title="ERA5 Data - How is a wind gust defined?" Tags="|meteorology|wind|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24440" PostTypeId="1" CreationDate="2022-10-20T18:14:15.397" Score="1" ViewCount="21" Body="&lt;p&gt;Not sure about the rainfall units in the wetland water balance of ACRU.&#xA;I have looked at the ACRU4 user manual which comes with the modelling tool installation and a dissertation covering the wetland HRU model structure (Gray, 2011) but didn’t see reference to the units. The units are also not mentioned in the drop-down list of variables in the output selector. Please advise?&lt;/p&gt;&#xA;" OwnerUserId="27363" LastActivityDate="2024-03-13T22:07:55.957" Title="ACRU4: rainfall units for the wetland water balance" Tags="|hydrology|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24441" PostTypeId="2" ParentId="24440" CreationDate="2022-10-20T18:14:15.397" Score="0" Body="&lt;p&gt;In both input and output files, the rainfall is in mm.&lt;/p&gt;&#xA;&lt;p&gt;Relative to other HRUs, the rainfall depths are the same, but the volumes are different because it depends on the HRU area. For this reason, it is easier to convert the rainfall depth to a volume if you are estimating a water balance.&lt;/p&gt;&#xA;&lt;p&gt;To convert the depth of rainfall falling on the wetland HRU to a volume, it would be [rainfall depth (mm) / 1000 ] * wetland area (km2)&lt;/p&gt;&#xA;&lt;p&gt;To work with the rainfall as a depth, the wetland rainfall depth is calculated as an area-weighted value, wetland rainfall depth (mm) = subcatchment rainfall (mm) * [wetland area (km2) / subcatchment area (km2) ]&lt;/p&gt;&#xA;" OwnerUserId="27363" LastActivityDate="2022-10-20T18:14:15.397" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24442" PostTypeId="1" CreationDate="2022-10-20T21:51:17.863" Score="2" ViewCount="86" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZMUbc.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZMUbc.jpg&quot; alt=&quot;This top image is Scotese's for 3.7 million years ago from https://www.academia.edu/11082185/Atlas_of_Neogene_Paleogeographic_Maps&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ya93u.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ya93u.jpg&quot; alt=&quot;The bottom image is for DeeptimeMaps who are affiliated with Petroleum, for 4 million years ago from https://deeptimemaps.com/global-paleogeography-and-tectonics-in-deep-time/&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Special attention paid particularly to the Arctic where the Hudson and Berent's sea are ocean in the above they are ocean, below they are land.&lt;/p&gt;&#xA;&lt;p&gt;In other places, Scotese's seems more accurate to me but I can's shake the feeling that up North, Scotese might be ignoring the effect of Glacial depression.&lt;/p&gt;&#xA;&lt;p&gt;For one, from this rate of isostatic rebound map,&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/y1zYI.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/y1zYI.png&quot; alt=&quot;Rate of Isostatic rebound pale yellow, neutral, towards red, positive, towards blue, negative&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Its is rebounding as much as land areas that were covered by Ice Sheets which implies it was just as deeply covered by ice sheets which is kinda weird, especially with areas of Ice over the Sea in Antarctica today being covered negative while the rest of the land glaciers are positive.&lt;/p&gt;&#xA;&lt;p&gt;This implies it was in a condition just as primed for having ice sheets as, say Scandinavia therefore, land.&lt;/p&gt;&#xA;&lt;p&gt;But which do you think is more accurate, particularly in the arctic.&lt;/p&gt;&#xA;" OwnerUserId="27828" LastActivityDate="2022-10-20T21:51:17.863" Title="Which depiction of the world map, with focus on dry land vs ocean do you think is more accurate? Scotese's or deeptimemaps?" Tags="|glaciology|isostasy|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24443" PostTypeId="2" ParentId="24433" CreationDate="2022-10-21T01:55:10.710" Score="2" Body="&lt;p&gt;Well, to start with, air does not strictly go from high pressure to low pressure. For example, in &lt;a href=&quot;https://en.wikipedia.org/wiki/Geostrophic_current&quot; rel=&quot;nofollow noreferrer&quot;&gt;geostrophic balance&lt;/a&gt; winds will move perpendicular to the pressure gradient.&lt;/p&gt;&#xA;&lt;p&gt;Fronts form in a process called &lt;a href=&quot;https://en.wikipedia.org/wiki/Frontogenesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;frontogenesis&lt;/a&gt;. To say that it is complicated might be an understatement. This process can be simplified into the &lt;a href=&quot;https://www.weather.gov/jetstream/cyclone&quot; rel=&quot;nofollow noreferrer&quot;&gt;Norwegian Cyclone Model&lt;/a&gt;. As an analogy, the cold air usually is the &amp;quot;bully&amp;quot; as it is denser. As the cold air is denser, it undertakes the warm air. Meanwhile, the warm air is less dense and rises over the cold air. Eventually the cold front catches up with itself, cutting off the warm air, causing an occluded front. With the lack of warm air to the center of the low, the frontal system slowly dissipates. There is a far more technical description, but for that, I would have to discuss vorticity advection, positioning of jet streak, etc.&lt;/p&gt;&#xA;" OwnerUserId="704" LastEditorUserId="704" LastEditDate="2022-10-24T03:37:57.643" LastActivityDate="2022-10-24T03:37:57.643" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24445" PostTypeId="2" ParentId="24438" CreationDate="2022-10-21T10:05:29.780" Score="7" Body="&lt;p&gt;The &lt;a href=&quot;https://space.oscar.wmo.int/variables/view/wind_gust&quot; rel=&quot;noreferrer&quot;&gt;WMO definition of wind gust&lt;/a&gt; for observing stations is,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Maximum value, over the observing cycle, of the 3-second running average wind speed.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;which is the definition you've found.  The ECMWF doc you've linked to says,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This duration is shorter than a model time step, and so the ECMWF Integrated Forecasting System (IFS) deduces the magnitude of a gust within each time step from the time-step-averaged surface stress, surface friction, wind shear and stability.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The details of this calculation can be found in the&#xA;&lt;a href=&quot;https://www.ecmwf.int/en/elibrary/20198-ifs-documentation-cy47r3-part-iv-physical-processes&quot; rel=&quot;noreferrer&quot;&gt;IFS documentation&lt;/a&gt; (S3.9.4) and there's a more readable summary in an old ECMWF newsletter by &lt;a href=&quot;https://www.ecmwf.int/en/elibrary/17487-parametrization-convective-gusts&quot; rel=&quot;noreferrer&quot;&gt;Bechtold and Bidlot (2009)&lt;/a&gt;.  My interpretation is that this is a parameterization of V_3_X that's calculated every model time step, so X is the atmospheric time step length (e.g., about 90 to 1200 s, depending on model resolution) for the instantaneous output field.  The aggregated period maximum output fields that are also available will be simply the maximum V_3_X over that period.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2022-10-21T10:05:29.780" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24446" PostTypeId="1" CreationDate="2022-10-21T20:48:55.507" Score="2" ViewCount="202" Body="&lt;p&gt;I have information about total rainfall during a 24-hour, 1 in 100-year storm event for a location. (source: &lt;a href=&quot;https://hdsc.nws.noaa.gov/hdsc/pfds/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://hdsc.nws.noaa.gov/hdsc/pfds/index.html&lt;/a&gt;). I would like to use this information and create a realistic time series of rainfall over the 24 hour time period, in the increments of 10 seconds.&lt;/p&gt;&#xA;&lt;p&gt;How can I achieve this? I can assume uniform distribution, which would be very naive. Are there any guidelines on what kind of distribution is appropriate?&lt;/p&gt;&#xA;" OwnerUserId="27834" LastEditorUserId="2470" LastEditDate="2022-10-22T00:26:27.787" LastActivityDate="2022-10-22T23:11:08.143" Title="How to simulate rainfall for a 1 in 100 year storm event?" Tags="|climate-change|hydrology|precipitation|flooding|runoff|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24447" PostTypeId="1" CreationDate="2022-10-21T21:52:36.917" Score="3" ViewCount="59" Body="&lt;p&gt;While looking through the &lt;a href=&quot;https://www.usbr.gov/lc/region/g4000/24mo_MIN.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;&amp;quot;minimum inflow&amp;quot; 24-month projection for the Colorado River basin&lt;/a&gt;, I noticed something odd for the Lake Mead chart: an expected negative inflow from side streams in June 2023.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;Date      Glen release  Side inflow  Evap losses&#xA;Jun 2023  577           -13          44 &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Where's the water going?  It's not evaporating -- that's accounted for elsewhere.  As far as I know, the Colorado has no distributaries between Glen Canyon Dam and Lake Mead, and no significant users.  The ground should be pretty well saturated after spring runoff.  So what's happening to the 13,000 acre-feet (16,000 cubic meters) of water?&lt;/p&gt;&#xA;" OwnerUserId="2643" LastActivityDate="2022-10-21T21:52:36.917" Title="Where's the Colorado River water going between Glen Canyon and Lake Mead?" Tags="|hydrology|rivers|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24448" PostTypeId="1" CreationDate="2022-10-22T08:52:15.637" Score="6" ViewCount="316" Body="&lt;p&gt;My textbook for a historical geography class mentions a couple of geological features it calls &amp;quot;basalt sills&amp;quot; (the sill of Rosh Pinah and one other).&lt;/p&gt;&#xA;&lt;p&gt;I'm a total newbie to geology, but the term basalt sill is confusing me. As best I can tell... 1. basalt is an extrusive rock but 2. a sill is an intrusive formation. Is basalt sill a contradiction in terms?&lt;/p&gt;&#xA;&lt;p&gt;Thanks for your help.&lt;/p&gt;&#xA;" OwnerUserId="27836" LastActivityDate="2022-10-22T22:40:53.670" Title="Basalt sill - a contradiction in terms?" Tags="|geology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24449" PostTypeId="2" ParentId="24448" CreationDate="2022-10-22T15:54:21.630" Score="4" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Basalt&quot; rel=&quot;nofollow noreferrer&quot;&gt;Basalt&lt;/a&gt; is an &lt;a href=&quot;https://www.usgs.gov/faqs/what-are-igneous-rocks&quot; rel=&quot;nofollow noreferrer&quot;&gt;igneous rock&lt;/a&gt; - derived from a molten rock. When molten basalt is injected, or simply enters an underground void, or when it enters between two easily separable geological layers, it intrudes into the existing geology. Basalt can also be deposited on the surface of the Earth via volcanic eruptions.&lt;/p&gt;&#xA;&lt;p&gt;In geology, a &lt;a href=&quot;https://en.wikipedia.org/wiki/Sill_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;sill&lt;/a&gt; is an intrusion that is horizontal, or subhorizontal, whereas a &lt;a href=&quot;https://en.wikipedia.org/wiki/Dike_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;dike&lt;/a&gt; is an intrusion that is vertical or subvertical.&lt;/p&gt;&#xA;&lt;p&gt;So, a basalt sill is not a contradiction, but tells you two things: firstly the type of rock, which is basalt and secondly, the way it was formed: as a subhorizontal intrusion into existing geological formations.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="6298" LastEditDate="2022-10-22T22:40:53.670" LastActivityDate="2022-10-22T22:40:53.670" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24450" PostTypeId="2" ParentId="24448" CreationDate="2022-10-22T18:50:50.257" Score="7" Body="&lt;p&gt;I think I know where the confusion comes from. You need at least two criteria to define a magmatic rock: a composition, and a texture. A magma of the same composition can yield two different rocks depending on the texture. For instance, a mafic melt can yield a gabbro if the texture is coarse-grained, or a basalt if it is fine-grained. Same with a felsic melt and granite/rhyolite.&lt;/p&gt;&#xA;&lt;p&gt;Now, &lt;em&gt;usually&lt;/em&gt;, intrusive rocks tend to be coarse-grained, because they cool slowly, hence crystals have time to grow. And &lt;em&gt;usually&lt;/em&gt;, extrusive rocks tend to be fine-grained because they cool quickly, so crystals don't have enough time to grow. That's why one could think that basalt is restricted to extrusive rocks. But if you take a mafic melt, and cool it quickly in an intrusive setting, then you end up with a mafic, fine-grained rock, i.e., a basalt. This can happen with sills, which can be quite thin (&amp;lt; 1 m in some cases) thus can cool quickly due to the contact with the cold, host rock.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2022-10-22T18:50:50.257" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24451" PostTypeId="2" ParentId="24446" CreationDate="2022-10-22T23:11:08.143" Score="3" Body="&lt;p&gt;Sounds a bit unfeasible to me to really and truly properly simulate... a bit like asking the timeline of how a hypothetical 100 story building would be built.&lt;/p&gt;&#xA;&lt;p&gt;There's certainly some patterns to how extreme rainfall events can go: stationary front/stalled tropical cyclone/slow moving chained supercells (perhaps extremely large hail can be a factor in this [though I'm not sure how well that's measured in precipitation totals really])/maximized terrain ascent/flow off very moist water body. And some guidelines to the process as well: there is a &lt;a href=&quot;https://earthscience.stackexchange.com/questions/5169/is-there-an-upper-bound-to-the-amount-of-rain-that-can-fall-in-an-hour&quot;&gt;maximum convective rainfall rate&lt;/a&gt;, and times of the day when certain precipitation events are favored [diurnal seabreeze, nocturnal low-level jet, etc].  You could use all these as a rough guide in your simulation.&lt;/p&gt;&#xA;&lt;p&gt;Or if you really wanted to go intense on it, you could try gathering a distribution of like the top percentile of rain events, either in general, for the region, or for the site of interest (or from nearby sites with longer datasets if necessary), and try to work off the guidelines of the temporal &amp;quot;shape&amp;quot; and timing of such events.  (I can't offhand remember any summary datasets of the temporal distribution of major flash floods, though it's not impossible that at least specific types have some out there if you search the journals?)&lt;/p&gt;&#xA;&lt;p&gt;You could then either just use a representative &amp;quot;typical&amp;quot; layout given by that data, or instead come up with some complex &amp;quot;simulation&amp;quot; production code for events using randomization along with the probability densities of each hourly value.&lt;/p&gt;&#xA;&lt;p&gt;But even then, a rare flood event can often be a bit different in style versus more &amp;quot;typical&amp;quot; floods; for example some areas may only see remnant tropical cyclones or strong tropical cyclones like once in a century.  So they wouldn't match the observed patterns that well.&lt;/p&gt;&#xA;&lt;p&gt;The big picture is still that some events can be many hours of strong rain, others can be shorter duration of extreme rain, or even multiple separate rounds of storms.  So simulating a flood's rainfall timing... especially at that temporal resolution (I'm not sure standard rain gauges measure to near that time increment; certainly in past recordkeeping generally the base time period has been hourly, though with start and end times to the minute, and potentially datasets obtainable down to nearer 5 minute resolution [&lt;a href=&quot;https://wxobservers.freeforums.net/thread/1005/asos-minute-observations-on-internet&quot; rel=&quot;nofollow noreferrer&quot;&gt;ASOS&lt;/a&gt;] or perhaps shorter from some mesonets/micronets may be found with enough work.  Or radar datasets may be available to use as non-in-situ estimates, though they'll mostly be about 5 minutes resolution as well, except for rarer focused rapid-scan/mobile/phased array datasets).&lt;/p&gt;&#xA;&lt;p&gt;So you have to weigh how important realism is.  If you want to attempt to really get the maximum reality, it may take some serious work.  If you want a rough estimate, you could use similar events of the same type/in the region of interest as a fair idea.  But if you heard a foot of snow will fall in a storm... will it be concentrated over a few hours of heavy blizzard, or spread of more steady precipitation over the entire day?  It can well be either.  And that's the case with rainfall events too.  So I'd argue there's never going to be a perfect expectation.  If your study is on something like flood evolution, probably go towards a worst-case scenario, and focus it on a fairly quick event.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2022-10-22T23:11:08.143" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24452" PostTypeId="1" CreationDate="2022-10-23T20:53:50.030" Score="4" ViewCount="103" Body="&lt;p&gt;If the &lt;a href=&quot;https://en.wikipedia.org/wiki/Giant-impact_hypothesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;Theia event&lt;/a&gt; was true, could it have formed a great deposit of diamonds out of the impact?? If that was the case, is it correct to suppose that somewhere hidden within the surface of the Earth there is a great diamond deposit resulting from that huge collision?&lt;/p&gt;&#xA;" OwnerUserId="27842" LastEditorUserId="81" LastEditDate="2022-12-29T15:31:43.810" LastActivityDate="2022-12-30T15:43:57.120" Title="Could a great diamond deposit have been derived from the Theia event?" Tags="|earth-history|diamond|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24453" PostTypeId="1" CreationDate="2022-10-24T15:38:24.160" Score="4" ViewCount="111" Body="&lt;p&gt;I am looking to plot a &lt;code&gt;Tephigram&lt;/code&gt; using Python and so far I have noticed that there are no real ways of doing so and I do not have the meteorological training to start from a &lt;code&gt;SkewT&lt;/code&gt; plot and customize it to a &lt;code&gt;Tephigram&lt;/code&gt;. I am currently using &lt;a href=&quot;https://unidata.github.io/MetPy/latest/examples/Advanced_Sounding.html#sphx-glr-examples-advanced-sounding-py&quot; rel=&quot;nofollow noreferrer&quot;&gt;MetPy&lt;/a&gt; to create plots like the one below but I do not think it is a valid &lt;code&gt;Tephigram&lt;/code&gt;. I have looked at these &lt;a href=&quot;https://github.com/Unidata/MetPy/issues/418&quot; rel=&quot;nofollow noreferrer&quot;&gt;Issue 1&lt;/a&gt;,&lt;a href=&quot;https://github.com/Unidata/MetPy/issues/613&quot; rel=&quot;nofollow noreferrer&quot;&gt;Issue 2&lt;/a&gt; and &lt;a href=&quot;https://github.com/Unidata/MetPy/issues/1731&quot; rel=&quot;nofollow noreferrer&quot;&gt;Issue 3&lt;/a&gt; as well as this &lt;a href=&quot;https://github.com/leifdenby/tephigram_python&quot; rel=&quot;nofollow noreferrer&quot;&gt;library&lt;/a&gt;, but I am open to any library or method.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Y1JHB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Y1JHB.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27848" LastActivityDate="2022-10-24T15:38:24.160" Title="Python way of plotting a Tephigram and Hodograph" Tags="|python|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24454" PostTypeId="1" CreationDate="2022-10-24T15:44:21.433" Score="3" ViewCount="49" Body="&lt;p&gt;The research I've done says that the rivers are fed by alpine snow, lakes and rains in the Taurus mountains but I'm specifically interested in whether the rains/snows and the water that feeds the lakes come from evaporation from the Mediterranean, or is it more from the Black sea or Caspian sea or somewhere else?&lt;/p&gt;&#xA;" OwnerUserId="27849" LastActivityDate="2022-10-24T15:44:21.433" Title="Where does the water in the Euphrates and Tigras rivers come from?" Tags="|rivers|rainfall|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24455" PostTypeId="1" CreationDate="2022-10-25T09:28:13.853" Score="3" ViewCount="94" Body="&lt;p&gt;This is my first post. I am trying my best to follow all the &amp;quot;how to ask a question&amp;quot; guidelines and hopefully my question will be clear.&lt;/p&gt;&#xA;&lt;p&gt;I am trying to find the change of slope in a time series. I used the &lt;a href=&quot;https://pypi.org/project/ruptures/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ruptures&lt;/a&gt; (for 2 break points using &lt;code&gt;model = rpt.Dynp(model=&amp;quot;l1&amp;quot;&lt;/code&gt;) and this is what I got (please see the attached image). &lt;a href=&quot;https://i.stack.imgur.com/7IIrB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7IIrB.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I am not happy with the break point location. Based on my visual inspection of the data, I feel the break-point is earlier than what I am getting. I wanted to do a &amp;quot;Two-phase linear regression&amp;quot; to check my results. I found that there is a function available in &lt;a href=&quot;https://www.mathworks.com/matlabcentral/fileexchange/26804-two-phase-linear-regression-model&quot; rel=&quot;nofollow noreferrer&quot;&gt;Matlab&lt;/a&gt;. I am wondering if there is any python package available to do the same thing what this Matlab function does, because I know nothing about Matlab.&lt;/p&gt;&#xA;&lt;p&gt;Thank you in advance for your inputs.&lt;/p&gt;&#xA;&lt;p&gt;[If anyone is wondering what happens if I try to find 3 or 4 break-points in my data, instead of looking for 2 break-points, then please see the images below. I am still not happy with the first change point location.]&#xA;&lt;a href=&quot;https://i.stack.imgur.com/3hvsH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3hvsH.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/wK4Te.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wK4Te.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20531" LastActivityDate="2022-10-26T06:32:01.197" Title="Two-phase linear regression model in Python" Tags="|python|climate-data|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24456" PostTypeId="1" CreationDate="2022-10-25T11:53:17.603" Score="1" ViewCount="49" Body="&lt;p&gt;Hi I am looking for a list or a database where I can find the basic thermodynamic data like the standard enthalpy or standard entropy! Do you know of one?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2022-10-25T11:53:17.603" Title="List of thermodynamic properties of various minerals" Tags="|mineralogy|thermodynamics|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24457" PostTypeId="2" ParentId="24432" CreationDate="2022-10-25T12:45:09.867" Score="2" Body="&lt;p&gt;Yes, but the effect of any plausible number or mass of satellites will be negligible.&lt;/p&gt;&#xA;&lt;p&gt;The force due to gravity between two objects is proportional to the masses of the two objects and inversely proportional to the distance between them. The mass of the Earth is constant, so the things that matter here are the mass of the other object, and how far away it is.&lt;/p&gt;&#xA;&lt;p&gt;Large satellites mass a few tonnes, while most are lighter. The mass of the moon is 7x10&lt;sup&gt;19&lt;/sup&gt; tonnes.&lt;/p&gt;&#xA;&lt;p&gt;The moon is further away, which weakens its effects, but only a few hundred times further away. So the effect of the moon will be somewhere (very roughly) around 10&lt;sup&gt;17&lt;/sup&gt; times that of a single satellite.&lt;/p&gt;&#xA;&lt;p&gt;So unless we were to launch literally trillions of satellites, we can continue to treat their effects as negligible for most purposes.&lt;/p&gt;&#xA;&lt;p&gt;(it is a bit more complex because of the question of how these satellites are distributed - some of them will cancel out others, and so forth - but the forces will be so small that I don't imagine it matters)&lt;/p&gt;&#xA;" OwnerUserId="39" LastEditorUserId="2470" LastEditDate="2022-10-25T16:46:48.500" LastActivityDate="2022-10-25T16:46:48.500" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24458" PostTypeId="2" ParentId="10823" CreationDate="2022-10-25T14:23:59.013" Score="1" Body="&lt;p&gt;&amp;quot;Fossil&amp;quot; originally meant that something was &amp;quot;dug deep out of the Earth&amp;quot; and the first published issuance of the term &amp;quot;fossil fuel&amp;quot; predates by over two centuries, the exclusive association during the 19th Century of the word &amp;quot;fossil&amp;quot; to meaning &amp;quot;mineralized remains of dead biological life forms&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Also, the &amp;quot;10km depths limit&amp;quot; is a fallacy asserted by people who fail to recognize very few instances of going deeper than 10km down into the Earth's crust even exist, and that anything much beyond 15km is only theorem, not de facto, regardless of how agreed upon the &amp;quot;accepted scientific consensus&amp;quot; may be on the subject; and while much of it could very well be accurate overall, does not negate that all of it is educated guesswork based solely upon our current understanding of elemental physics, and surface and near-surface observations with limited-scope subterranean exploration.&lt;/p&gt;&#xA;" OwnerUserId="27858" LastActivityDate="2022-10-25T14:23:59.013" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24459" PostTypeId="2" ParentId="24455" CreationDate="2022-10-26T06:19:38.973" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;I wanted to do a &amp;quot;Two-phase linear regression&amp;quot; to check my results.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You aren't doing that. By specifying &lt;code&gt;model=&amp;quot;l1&amp;quot;&lt;/code&gt;, you are asking the package to use a piecewise constant model (rather than a linear regression) for each segment. This models each segment as the mean of all the elements in that segment. The error is calculated as the sum of the absolute values of the difference between each element and the mean (the &lt;span class=&quot;math-container&quot;&gt;$L^1$&lt;/span&gt; norm). Apparently asking for two breakpoints means one internal breakpoint, or two segments that collectively span the dataset.&lt;/p&gt;&#xA;&lt;p&gt;That is not a good model of your dataset, and it is not a linear regression.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2022-10-26T06:32:01.197" LastActivityDate="2022-10-26T06:32:01.197" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24460" PostTypeId="2" ParentId="265" CreationDate="2022-10-26T09:14:37.450" Score="1" Body="&lt;p&gt;Quote from:&#xA;&lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/B9780444506627000032?via%3Dihub&quot; rel=&quot;nofollow noreferrer&quot;&gt;Developments in Petroleum Science&lt;/a&gt;, Vol. 60. dx.doi.org/10.1016/B978-0-444-50662-7.00003-2 © 2013 Elsevier B.V. All rights reserved.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Geology and geophysics are two constituent disciplines of geoscience or earth&#xA;science. As we discussed in Chapter 2, geology, being an observational science,&#xA;involves the study of the earth by direct analysis of rocks and formations, either&#xA;from surface exposure or from boreholes, tunnels, and mines. It involves the&#xA;deduction of the earth’s structure, texture, composition, or history, by the analysis of such observations. Geophysics, on the other hand, is a science that deals&#xA;with the physical features of the earth’s surface and its internal structure. It&#xA;applies the principles of physics to the study of the earth. Virtually all of what&#xA;we know about the earth below the limited depths to which boreholes or mine&#xA;shafts have penetrated has been derived from geophysical observations.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="27862" LastEditorUserId="2470" LastEditDate="2022-10-26T10:17:37.367" LastActivityDate="2022-10-26T10:17:37.367" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24461" PostTypeId="1" AcceptedAnswerId="24463" CreationDate="2022-10-26T14:18:44.273" Score="4" ViewCount="243" Body="&lt;p&gt;I would naively assume that when the earth was formed and still molten, all the heavy stuff such as gold would have sunk to the centre, so almost nothing would remain in the earth's crust where humans could access it. Is it that &amp;quot;almost nothing&amp;quot; is not nothing? Or was it added to the surface by later impact events as &lt;a href=&quot;https://en.wikipedia.org/wiki/Ore_genesis#Cosmic_origins_of_rare_metals&quot; rel=&quot;nofollow noreferrer&quot;&gt;suggested on Wikipedia&lt;/a&gt;?&lt;/p&gt;&#xA;&lt;p&gt;The answers to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/2294/why-is-there-uranium-in-earths-crust&quot;&gt;Why is there Uranium in Earth's Crust?&lt;/a&gt; and &lt;a href=&quot;https://earthscience.stackexchange.com/questions/8214/why-is-uranium-only-in-the-crust-really&quot;&gt;Why is uranium only in the crust, really?&lt;/a&gt; seem to be that uranium chemistry is such that it was carried along with lighter elements to the surface, but isn't gold chemistry much less favourable for such processes? Is this why gold is &lt;a href=&quot;https://en.wikipedia.org/wiki/Uranium_ore&quot; rel=&quot;nofollow noreferrer&quot;&gt;500 times less common than uranium&lt;/a&gt; in the earth's crust?&lt;/p&gt;&#xA;" OwnerUserId="27775" LastActivityDate="2023-03-15T11:16:54.973" Title="Why is there gold in the earth's crust?" Tags="|geochemistry|minerals|crust|ore|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24462" PostTypeId="1" CreationDate="2022-10-26T16:21:36.363" Score="6" ViewCount="204" Body="&lt;p&gt;When looking at this map of bedrock geology of the Illinois and Ozark basins (sourced from &lt;a href=&quot;https://isgs.illinois.edu/maps/statewide/geological-and-geophysical-maps-illinois-basin-ozark-dome-region&quot; rel=&quot;nofollow noreferrer&quot;&gt;Geological and Geophysical Maps of the Illinois Basin-Ozark Dome Region&lt;/a&gt;),&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0XSHH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0XSHH.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I can't help but notice that Missouri—and only Missouri—shows a large number of small mounds and craters:&lt;/p&gt;&#xA;&lt;p&gt;Example from the Ozark plateau:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lgIrX.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lgIrX.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Example from around Kansas city:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/atRmI.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/atRmI.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;What am I seeing here&lt;/strong&gt;?&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Surely these aren't impact craters (cool as that would be)—as nearly none of them show up in lists I can find of known or suspected craters (which seem limited to the &lt;a href=&quot;https://en.wikipedia.org/wiki/38th_parallel_structures&quot; rel=&quot;nofollow noreferrer&quot;&gt;38th parallel structures&lt;/a&gt; and the &lt;a href=&quot;https://en.wikipedia.org/wiki/Weaubleau_structure&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weaubleau structure&lt;/a&gt;).&lt;/li&gt;&#xA;&lt;li&gt;Are they an artifact in how the data was collected (ex. perhaps these features do not really exist?)?&lt;/li&gt;&#xA;&lt;li&gt;Are patterns like this common in bedrock maps of other regions of the world?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I do not see similar structures in Illinois, for instance:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vbz4t.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vbz4t.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27864" LastEditorUserId="18088" LastEditDate="2022-10-30T05:57:48.097" LastActivityDate="2022-10-31T03:38:06.807" Title="What are the craters and mounds in this Missouri bedrock map?" Tags="|geology|regional-geology|bedrock|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24463" PostTypeId="2" ParentId="24461" CreationDate="2022-10-26T17:55:05.133" Score="4" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Is it that &amp;quot;almost nothing&amp;quot; is not nothing?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It's obviously &amp;quot;almost nothing&amp;quot; because there still is gold in the Earth's crust. That said, while gold is 20 times more abundant in the solar system than is uranium, it is 600 times less abundant than uranium in the Earth's crust. That's a close to a perfect differentiation. No chemical process is perfect. After all, there is still a good amount of iron and nickel in the Earth's crust and mantle. Not as much as in the core, but still a good amount.&lt;/p&gt;&#xA;&lt;p&gt;Whether the gold that remains in the crust is primordial or came from late bombardment asteroids remains highly debated.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-10-26T17:55:05.133" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24464" PostTypeId="1" CreationDate="2022-10-27T17:39:01.130" Score="3" ViewCount="55" Body="&lt;p&gt;Are there any simple models to approximate soil moisture level (%) as a function of distance from a waterbody (say a lake)? If one assigns saturation level of lake to 100% , then are there any approximations one can use to determine saturation level of land mass at say distance x from the center of lake? I understand that these calculations will depend on weather and other parameters like soil type, for example.&lt;/p&gt;&#xA;" OwnerUserId="27834" LastActivityDate="2022-10-27T17:39:01.130" Title="Approximating Soil Moisture level" Tags="|climate|hydrology|groundwater|flooding|soil-moisture|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24465" PostTypeId="1" CreationDate="2022-10-27T19:31:52.177" Score="4" ViewCount="74" Body="&lt;p&gt;Does the IPCC publish its references (i.e. the references used in the report, &lt;em&gt;not&lt;/em&gt; citations for the reports or chapters themselves) beyond what is in the PDFs of the reports themselves?&lt;/p&gt;&#xA;&lt;p&gt;I'm looking for something like a RIS or BibTeX file (or even a cleanly formatted CSV) of all the references cited, for each of the chapters of AR6 and hopefully AR5. Copying and pasting references out of the Chapter PDFs available on the IPCC's website is a formatting mess not conducive to any sort of analysis on the references.&lt;/p&gt;&#xA;" OwnerUserId="27866" LastActivityDate="2023-04-27T19:21:03.720" Title="IPCC AR6 References" Tags="|climate-change|climate|reference-request|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24466" PostTypeId="1" CreationDate="2022-10-28T07:26:50.680" Score="3" ViewCount="46" Body="&lt;p&gt;In this video Earth's carbon cycle is investigated with a bit of maths.&#xA;&lt;a href=&quot;https://www.youtube.com/watch?v=aIOrF0-R33o&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=aIOrF0-R33o&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It is in German, but the idea behind I can describe easily:&lt;/p&gt;&#xA;&lt;p&gt;There are reservoirs of carbon:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Atmosphere A&lt;/li&gt;&#xA;&lt;li&gt;Biosphere B&lt;/li&gt;&#xA;&lt;li&gt;Upper sea M&lt;/li&gt;&#xA;&lt;li&gt;Deep sea T&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;This is the relevant image:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Bi8J0.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Bi8J0.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The author has taken the image (most likely) from the IPCC report and adjusted the in- and out flows so that all four reservoir contents are in quasi-static equilibrium for simplicity. For the flows from F(X-&amp;gt;Y) from X to Y he assumes, that it depends only on the content X, in particular for instance&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$F(A\rightarrow B) = \frac{110}{600}\cdot [A]$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;I'm aware that the model is very crude but nevertheless, what's the idea behind? It would mean, that F(X-&amp;gt;Y) depends only on X and not on Y. Take for instance F(A-&amp;gt;B) and we double carbon in A, the assumption would imply, that biomass increases also by factor two - otherwise the additional carbon cannot be &amp;quot;absorbed&amp;quot; by B. Same for F(A, M). When CO&lt;sub&gt;2&lt;/sub&gt; increases in air, temperature of M would rise too, but then less CO&lt;sub&gt;2&lt;/sub&gt; would be taken by the warmer water, so the coefficient of transport would change.&lt;/p&gt;&#xA;&lt;p&gt;Is there a way to justify the assumption in a first approximation?&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="2470" LastEditDate="2022-10-29T08:48:55.677" LastActivityDate="2022-10-29T08:48:55.677" Title="How can carbon flows be modeled mathematically?" Tags="|climate-change|climate-models|co2|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24467" PostTypeId="1" CreationDate="2022-10-28T16:31:30.880" Score="4" ViewCount="91" Body="&lt;p&gt;Solar panels create electricity from (sun)light. It stands to reason that more hours of light equals more electricity. This is a gross simplification of the problem, as light strength, heat, how quickly it gets dirty, service hours and even distance to where the electricity is used influence this further. For now I want to keep this question simple. More light hours year round is better.&lt;/p&gt;&#xA;&lt;h2&gt;Ocean 'deserts'&lt;/h2&gt;&#xA;&lt;p&gt;Sunlight hours are reasonably well available for cities and some areas, but not for the ocean.&lt;/p&gt;&#xA;&lt;p&gt;I'm looking into solar panels on the ocean. For this I would like to know if there are areas of the ocean with as much direct sunlight hours as possible. That means few (no) clouds overhead to block the sun, no mist or any weather phenomenon that blocks sunlight from solar panels.&lt;/p&gt;&#xA;&lt;p&gt;At first I thought there would be little difference where you would put solar panels, as it is a pretty uniform mass of water. However, we can see that the oceans and seas build up different patterns. We have cold and hot currents and areas where different kinds of storms are created for example. One influences the cloud formation and the other is a result of differences in the ocean. Then it stands to reason that some parts of the ocean get more sunlight hours than others. Of course it is easy to assume this is near the equator, but thanks to cloud generation it might not be so simple. Though &amp;quot;around the equator&amp;quot; would not be specific enough for me.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;What part(s) of the ocean have the most sunlight hours?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="27869" LastActivityDate="2022-10-28T16:31:30.880" Title="Highest amount of sun hours in the ocean" Tags="|meteorology|oceanography|sun|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24469" PostTypeId="1" CreationDate="2022-10-29T17:01:02.973" Score="2" ViewCount="59" Body="&lt;p&gt;I am looking to draw form lines on this map based on the strike and dip measurements taken on site. From what I have gathered it is an anticline with a possible second fault to the right hand side. Can anyone confirm this/give some guidance on where the form lines would go?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/he9f7.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/he9f7.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27876" LastEditorUserId="18081" LastEditDate="2022-10-30T07:17:01.067" LastActivityDate="2022-10-30T07:17:01.067" Title="Form Lines from Strike and Dip measurements" Tags="|geology|geography|mapping|homework|structural-geology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24472" PostTypeId="2" ParentId="24462" CreationDate="2022-10-31T03:38:06.807" Score="5" Body="&lt;p&gt;While I can't confirm that it correlates perfectly to the points in the map, the answer may be that at least a subset of them are the same structures that Bretz proposed a theory for in 1950 (in &lt;a href=&quot;https://pubs.geoscienceworld.org/gsa/gsabulletin/article-abstract/61/8/789/4373/ORIGIN-OF-THE-FILLED-SINK-STRUCTURES-AND-CIRCLE&quot; rel=&quot;noreferrer&quot;&gt;&amp;quot;Origin of the Filled-Sink Structures and Circle Deposits of Missouri&lt;/a&gt;&amp;quot;).&lt;/p&gt;&#xA;&lt;p&gt;I learned this fromthe following passage in Charles Spencer's &lt;em&gt;Roadside Geology of Missouri&lt;/em&gt; (Missoula: Mountain Press, 2011), which I came across after posting the question (p. 137–9):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Ordovician dolomite beds on the northern and northwestern flanks of the Ozark Dome are peppered with hundreds of small, circular or elliptical structures in which the rocks inside are younger than those surrounding them.  They vary in size from tens to hundreds of feet across.  Most are found in the Jefferson City Dolomite, but some are in the Roubidoux Formation...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Many explanations have been proposed for how these structures formed.  The earliest hypothesis was that they were stream channels eroded into the surface of the host rock during the Late Ordovician time when sea level temporarily fell.  That explained the presence of crossbedded sandstone... but not the circular shapes or the Presence of Pennsylvanian coal or clay beds.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A second explanation was that they were ancient sinkholes fromed by collapse into a cavern.  This idea accounted for the circular shapes and the different types and ages of sediment filling them.  Some of the structures may indeed have formed in this way.  But in many of the structures, the in-filling rocks are not broken as would be expected if collapse had occurred.  In fact, the beds inside some of the structures are horizontal.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In 1950, Missouri geologist J. Harlen Bretz proposed another, perhaps more unusual explanation for how the structures formed, and he named them &lt;em&gt;filled-sink structures&lt;/em&gt;, sometimes shortened to &lt;em&gt;filled sinks&lt;/em&gt;.  In Bretz's model, the structures were indeed the result of groundwater erosion, but without the formation of caves.  Rather, microscopic grains of dolomite were dissolved slowly over time, creating tiny spaces in the rock.  The loss of rock allowed the dolomite bed to compact under the weight of overlying beds.  As it did so, beds above it sank very slowly into the structure.  The amount that younger beds settled varied, depending on the amount of dolomite rock mass removed: the more rock removed, the greater the subsidence...  Once uplift of the Ozark Dome began in earnest in Late Pennsylvanian time, the water table across the Salem Plateau dropped, ending the process...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Bretz's model accounts for the observed characteristics of many of the structures...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Be that as it may, some circular features found in Ordovician dolomite in the Ozarks are indeed attributed to collapse of deeper caves.  These structures, called &amp;quot;circles,&amp;quot; are similar in shape to filled sinks but always contain broken, tilted, and shattered beds rather than horizontal strata.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="27864" LastActivityDate="2022-10-31T03:38:06.807" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24473" PostTypeId="1" CreationDate="2022-10-31T08:49:48.983" Score="3" ViewCount="79" Body="&lt;p&gt;I come from a background in research in pure Mathematics and, after a period of self-learning, I am currently looking for a career in Deep Learning. I recently applied for a job in Deep Learning and Meteorology in the agriculture sector.&lt;/p&gt;&#xA;&lt;p&gt;They actually showed interest in my application, but asked me to propose a concrete plan for increasing my competence in the domain of meteorology. By any means, I don't want you to do the work for me, but I would like some experts to point me in the right direction to come up with this plan.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;What are the fundamental papers/books on meteorology that are&#xA;relevant in agriculture?&lt;/li&gt;&#xA;&lt;li&gt;What are some important papers on the state-of-the-art of Deep Learning applications in meteorology?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;If you think that there are more appropriate platforms where I could ask this questions or have other suggestions in general, please let me know. Thank you.&lt;/p&gt;&#xA;" OwnerUserId="27882" LastActivityDate="2022-10-31T08:49:48.983" Title="Meteorology and Deep Learning, where to start?" Tags="|meteorology|reference-request|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="24474" PostTypeId="1" AcceptedAnswerId="24475" CreationDate="2022-11-01T00:48:02.383" Score="4" ViewCount="76" Body="&lt;p&gt;This is an image of the wind in est Asia, south of Japan.&#xA;How do you explain this zone I circled in pink, where winds from north and south face each other? Thanks&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ep3yZ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ep3yZ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20532" LastActivityDate="2022-11-01T17:16:12.683" Title="Why south of Japan has a zone with winds facing each other?" Tags="|meteorology|oceanography|wind|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24475" PostTypeId="2" ParentId="24474" CreationDate="2022-11-01T17:05:53.690" Score="4" Body="&lt;p&gt;From the &lt;a href=&quot;https://www.weathercharts.org/japan-mslp.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;synopic weather chart&lt;/a&gt;, the zone you highlighted corresponds with a &lt;a href=&quot;https://en.wikipedia.org/wiki/Stationary_front&quot; rel=&quot;nofollow noreferrer&quot;&gt;stationary front&lt;/a&gt; just to the east of Taiwan.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2VuD3.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2VuD3.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2022-11-01T17:16:12.683" LastActivityDate="2022-11-01T17:16:12.683" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24476" PostTypeId="2" ParentId="24419" CreationDate="2022-11-01T17:29:51.053" Score="1" Body="&lt;p&gt;Less dense air tends to rise; in general, how much the atmosphere cools with elevation (in addition to humidity differences) drives a difference in density, and if that difference is larger than the stable condition, air masses tend to move up.  Thus afternoon thunderstorms, for example.&lt;/p&gt;&#xA;&lt;p&gt;An inversion is the opposite.  When the air higher up is warmer, it's also less dense, so the air lower down doesn't move up - the atmosphere is &amp;quot;extra stable&amp;quot;.  Since the air isn't moving up, air pollution isn't carried up and out by advection, and therefore accumulates as diffusion is much slower.  The same mechanism that carries moisture up to create afternoon thunderstorms isn't able to move pollution out.&lt;/p&gt;&#xA;" OwnerUserId="26713" LastActivityDate="2022-11-01T17:29:51.053" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24477" PostTypeId="1" CreationDate="2022-11-01T17:53:12.600" Score="1" ViewCount="41" Body="&lt;p&gt;I am setting up a MIKE Hydro model for a basin. I am getting extended validation errors on MIKE Hydro&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;Weirs(267) extended validation: StructureName: Q/h relation H-Neg must be increasing&#xA;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HrFa5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HrFa5.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I tried calculating the Q/h relations for the weir again but the error persists. Also as shown in the figure above, H-Neg is increasing so I don't see why MIKE-Hydro is giving this extended validation error.&lt;/p&gt;&#xA;" OwnerUserId="27888" LastActivityDate="2022-11-01T17:53:12.600" Title="MIKE Hydro Extended Validation Error: Q/h relation H-Neg must be increasing" Tags="|hydrology|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24478" PostTypeId="2" ParentId="24230" CreationDate="2022-11-02T01:58:06.833" Score="2" Body="&lt;p&gt;This is a difficult question to answer because the causal relationship between earthquakes is not something that is measured, but rather something that is modeled.&lt;/p&gt;&#xA;&lt;p&gt;Nonetheless, we often will say that aftershocks can persist for a very long time, after a larger earthquake in particular, wherein the rate of seismicity is higher than some nominal (or regional) background rate and decays with time. In Japan, aftershocks have been reported for more than 100 years following the Nobi earthquake.&lt;/p&gt;&#xA;&lt;p&gt;A typical model used to describe earthquake occurrence states that all earthquakes have some probability to be a 'mainshock', an aftershock, or an aftershock of an aftershock, (and so on). In this way, under the assumptions of this model, we can provide a probabilistic assessment of whether an earthquake is an aftershock, but not an absolute or deterministic assessment.&lt;/p&gt;&#xA;&lt;p&gt;As for the reason for the delay, there are many potential mechanisms. It is likely a combination of mechanisms. These may include the fact that frictional failure can start with slow nucleation (e.g. rate and state friction), fluids very slowly migrating through the crust as a response to the mainshock, a viscous response of the crust or mantle, and more.&lt;/p&gt;&#xA;" OwnerUserId="6245" LastActivityDate="2022-11-02T01:58:06.833" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24479" PostTypeId="1" AcceptedAnswerId="24480" CreationDate="2022-11-02T08:56:41.180" Score="12" ViewCount="764" Body="&lt;p&gt;I want to model future coastal flooding caused by sea-level rise under the latest IPCC scenarios at global scale. To this end, I use the &lt;strong&gt;Copernicus Digital Elevation Model&lt;/strong&gt; (Copernicus DEM: &lt;a href=&quot;https://spacedata.copernicus.eu/web/cscda/dataset-details?articleId=394198&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://spacedata.copernicus.eu/fr/collections/copernicus-digital-elevation-model&lt;/a&gt;). Silly me, I thought that the &lt;strong&gt;elevation height of 0m&lt;/strong&gt; of the Copernicus DEM was the &lt;strong&gt;mean sea level&lt;/strong&gt; of the data acquisition period of this DEM, but I have been told that it might not be the case.&lt;/p&gt;&#xA;&lt;p&gt;Does the elevation height of 0m of the Copernicus DEM correspond to mean sea level of the &lt;strong&gt;data acquisition period&lt;/strong&gt; of this DEM (&lt;em&gt;i.e.&lt;/em&gt;, 2011-2015)? Does it correspond to mean sea level of the &lt;strong&gt;vertical reference datum&lt;/strong&gt; of this DEM (&lt;em&gt;i.e.&lt;/em&gt;, Earth Gravitational Model 2008 - EGM 2008)? Or does it correspond to an &lt;strong&gt;older historical reference&lt;/strong&gt;?&lt;/p&gt;&#xA;&lt;p&gt;In the Copernicus DEM metadata it is written: &amp;quot;Ocean water bodies are set to the elevation height of 0m, including all seas, inlets, fjords and any other extensions of the ocean.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;I need to know what this 0m elevation height corresponds to and at what elevation is the mean sea level on this DEM.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Thank you!&lt;/p&gt;&#xA;" OwnerUserId="18828" LastEditorUserId="18828" LastEditDate="2023-05-26T07:33:39.283" LastActivityDate="2023-05-26T07:33:39.283" Title="Does the 0m elevation height of a Digital Elevation Model (Copernicus DEM) correspond to mean sea level?" Tags="|oceanography|hydrology|sea-level|gis|altitude|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24480" PostTypeId="2" ParentId="24479" CreationDate="2022-11-02T11:56:29.053" Score="13" Body="&lt;p&gt;From the website you linked:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Coordinate Reference System: Horizontal WGS84-G1150 (EPSG 4326) (DGED &amp;amp; DTED format), (EPSG 3035) for continental Europe and UTM , (EPSG 32740, 32622, 32738, 32620) for the French DOMs (INSPIRE format), Vertical EGM2008 (EPSG 3855)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So the vertical datum is EGM2008, which is a reference geoid (&lt;a href=&quot;https://doi.org/10.1029/2011JB008916&quot; rel=&quot;noreferrer&quot;&gt;Pavlis et al., 2012&lt;/a&gt;). It doesn't exactly correspond with mean sea level (MSL). There are local adjustments that need to be applied to change from 0m EGM2008 to MSL. I usually refer to the explanations at the &lt;a href=&quot;https://vdatum.noaa.gov/docs/datums.html&quot; rel=&quot;noreferrer&quot;&gt;VDatum&lt;/a&gt; site.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/kQFq6.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kQFq6.gif&quot; alt=&quot;geoid VDatum&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;They provide a calculator for the United States (&lt;a href=&quot;https://vdatum.noaa.gov/vdatumweb/vdatumweb&quot; rel=&quot;noreferrer&quot;&gt;https://vdatum.noaa.gov/vdatumweb/vdatumweb&lt;/a&gt;). For instance, for a point at 41.2 N and 69.5 W, that is 0m when using EGM2008, the height when referenced to MSL is 0.379m.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2022-11-02T11:56:29.053" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24481" PostTypeId="2" ParentId="20036" CreationDate="2022-11-03T00:12:34.913" Score="0" Body="&lt;p&gt;We have never seen anything that makes us believe their were other technological species. But if they didn't make it out of the stone age we might not find evidence even if they it did happen. So it is possible but there is nothing that makes us believe there were technological species.&lt;/p&gt;&#xA;&lt;p&gt;There is some good evidence against as well, we don't have anything in the fossil record with the kind of large brain we see in primates in the distant enough past to have a low risk of leaving fossils for its larger brained descendants. Humans are everywhere on the planet, and have been since we were still all hunter gatherers, there are probably millions of human fossils being formed from the last few thousand years. someone would notice the big brained thing that spread everywhere.&lt;/p&gt;&#xA;&lt;p&gt;So if it did exist it was extremely isolated and never developed the technology to spread.&lt;/p&gt;&#xA;&lt;p&gt;Once you have pottery and glass evidence is difficult to destroy. Cut stone stays obviously cut once buried, fire leaves weird traces we tend to notice, there are a lot of things that could show a technological species but we don't see any of it. The species would have to be a brief flash in the pan with a very rapid evolution to fit in what we know.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="2470" LastEditDate="2022-11-03T17:29:30.460" LastActivityDate="2022-11-03T17:29:30.460" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24482" PostTypeId="1" CreationDate="2022-11-03T09:10:58.980" Score="3" ViewCount="39" Body="&lt;p&gt;&lt;strong&gt;Background:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;For my studies I'm wanting and attempting to make a landfill greenhouse gas emissions (GHG) model that predicts the amount of greenhouse gas equivalent emissions (&lt;span class=&quot;math-container&quot;&gt;$GHG_{eq}$&lt;/span&gt; [tonnes/year]) by analysing a series of landfill core drill samples and extrapolating the data to predict how much GHGs would be produced if the samples can be representative of the landfill as a whole and allowed to naturally degrade. Note that this comes with the assumption of minimal heterogeneity which I know is not the best assumption for most landfills but I'm hoping to get a LOT of data (it's better than nothing).&lt;/p&gt;&#xA;&lt;p&gt;As the most notorious GHG from landfill is methane, I'm going to simplify this question to just predicting the amount of methane which would be produced from the (combustible) material in landfill assuming it would just sit there forever.&lt;/p&gt;&#xA;&lt;p&gt;Note that I have cross-posted my question &lt;a href=&quot;https://chemistry.stackexchange.com/questions/168959/how-can-combusted-methane-from-landfill-samples-be-quantified&quot;&gt;from the chemistry stack exchange&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;The Data:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I have this data which is the average of 3 landfill drill core samples and shows the type of waste which has been calculated from sorting and weighing different types of material found in landfill (Table 1) and the chemical composition and high heating value (HHV)/calorific value of the material (Table 2) which I've had tested in an independent lab. For Table 1, an assumed &amp;quot;type&amp;quot; of plastic, rubber, wood (etc.) is made with a constant chemical composition to simplify the model (although I do recognise that there are many different types of plastics and woods etc.).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oP4Km.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oP4Km.png&quot; alt=&quot;Data for average of 3 landfill drill core samples&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;The Method (?):&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I've seen the generic methanogenesis combustion reaction as:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{CO_2 + 4H_2 -&amp;gt; CH_4 + 2H_2O}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;I've also seen an elemental formula for hydrocarbon combustion along the lines of:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{C_xH_y + $(x + \frac{y}{4})$O_2 -&amp;gt; xCO_2 = $\frac{y}{2}$H_2O + $Heat + Light$}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;I know how to calculate the conversion rate going from any GHG such as &lt;span class=&quot;math-container&quot;&gt;$\ce{CO_2}$&lt;/span&gt; or &lt;span class=&quot;math-container&quot;&gt;$\ce{CH_4}$&lt;/span&gt; to &lt;span class=&quot;math-container&quot;&gt;$GHG_{eq}$&lt;/span&gt; but it's this first step - the predicting of the GHGs themselves with what formula - which I'm lost at.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;The Questions:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;How can I calculate &lt;span class=&quot;math-container&quot;&gt;$\ce{CH_4}$&lt;/span&gt; from landfill samples with the attached data and which reaction should be used?&lt;/li&gt;&#xA;&lt;li&gt;(Bonus) What other considerations should be accounted for with any of the other data? (e.g. the Sulfur going into &lt;span class=&quot;math-container&quot;&gt;$\ce{SO_2}$&lt;/span&gt; emissions (etc.)).&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="24500" LastEditorUserId="18081" LastEditDate="2022-11-04T08:32:48.133" LastActivityDate="2022-11-04T08:32:48.133" Title="How can combusted methane from landfill samples be quantified?" Tags="|atmosphere|models|air-pollution|greenhouse-gases|methane|" AnswerCount="0" CommentCount="3" ClosedDate="2022-11-12T22:25:57.997" ContentLicense="CC BY-SA 4.0" />
  <row Id="24483" PostTypeId="2" ParentId="24479" CreationDate="2022-11-03T12:16:19.960" Score="4" Body="&lt;p&gt;What I would do is cast the data into a new projection (if absolutely necessary).&lt;/p&gt;&#xA;&lt;p&gt;In particular, once you have a global model tied to a known reference ellipsoid you can convert that into local projection which can follow the local mean sea level more precisely.&lt;/p&gt;&#xA;&lt;p&gt;Personally, I'd use &lt;a href=&quot;https://pyproj4.github.io/pyproj/stable/api/proj.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;pyProj&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;For a more complete example, see e.g. &lt;a href=&quot;https://gis.stackexchange.com/questions/366769/adding-epsg-codes-to-pyproj&quot;&gt;this&lt;/a&gt; answer from GIS StackExchange, where data is converted from a given elevation system to another using the EPSG-codes.&lt;/p&gt;&#xA;" OwnerUserId="11300" LastActivityDate="2022-11-03T12:16:19.960" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24485" PostTypeId="1" AcceptedAnswerId="24486" CreationDate="2022-11-04T19:39:11.067" Score="4" ViewCount="170" Body="&lt;p&gt;While most ocean crust is formed from oceanic plate formations there are areas of the ocean (much of the Gulf of Mexico, Eastern US coast, North Sea, Arabian coast of India) which appear to be continental &amp;quot;land&amp;quot; for hundreds of miles before the shelf to the oceanic crust. How does this occur?&lt;/p&gt;&#xA;" OwnerUserId="27923" OwnerDisplayName="Gary" LastEditorUserId="27923" LastEditDate="2022-11-07T16:08:56.167" LastActivityDate="2022-12-24T23:09:50.060" Title="Why is some ocean on continental crust?" Tags="|geology|geophysics|oceanography|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24486" PostTypeId="2" ParentId="24485" CreationDate="2022-11-04T21:03:30.843" Score="2" Body="&lt;p&gt;It's a geology question more than a geography question. These crusts are components of tectonic plates. Continental crust is less dense than oceanic crust, so it tends to ride higher than the denser oceanic crust. Typically the deeper parts of the world are oceanic crust and where the oceans are by virtue of water running downhill - thus the name. It's not named based on the presence or lack of water on top of it, but on the chemical composition of the rock that makes up the tectonic plate. So you can have exposed oceanic crust on like volcanic islands and submerged continental crust in the areas you described.&lt;/p&gt;&#xA;&lt;p&gt;This is coming off from terrible memory from my geology undergrad like 15 odd years ago, FYI.&lt;/p&gt;&#xA;" OwnerDisplayName="Smasher" LastActivityDate="2022-11-04T21:03:30.843" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24487" PostTypeId="2" ParentId="21136" CreationDate="2022-11-06T17:00:18.130" Score="0" Body="&lt;p&gt;The term 'global warming' is a misleading misnomer. In fact climate change will bring more extremes in weather which will be bad for everyone. Sorry pal.&lt;/p&gt;&#xA;" OwnerUserId="27911" LastEditorUserId="2470" LastEditDate="2022-11-06T17:19:03.543" LastActivityDate="2022-11-06T17:19:03.543" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24488" PostTypeId="2" ParentId="21136" CreationDate="2022-11-06T18:52:07.433" Score="1" Body="&lt;p&gt;I'm originally from Poland &lt;em&gt;(mainly between 50-54°N&lt;/em&gt;) and the term &amp;quot;global warming&amp;quot; is &lt;strong&gt;counterproductive&lt;/strong&gt;, in my opinion.&lt;/p&gt;&#xA;&lt;p&gt;Of course, I would love to have a warmer climate. BUT... A better term, more accurately describing the factual reality:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;catastrophic climate collapse&lt;/li&gt;&#xA;&lt;li&gt;climate emergency&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I don't think there are any winners. Extreme weather events diminish any questionable benefits coming from warming.&lt;/p&gt;&#xA;&lt;h2&gt;Russia&lt;/h2&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/2021_Russia_wildfires&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/2021_Russia_wildfires&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/2022_Siberian_wildfires&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/2022_Siberian_wildfires&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;h2&gt;Norway&lt;/h2&gt;&#xA;&lt;h3&gt; is a negligible win...&lt;/h3&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZwqRd.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZwqRd.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Landslide: &lt;a href=&quot;https://www.youtube.com/watch?v=w45dbWBsaNI&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=w45dbWBsaNI&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;City far North: &lt;a href=&quot;https://en.wikipedia.org/wiki/Alta,_Norway&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Alta,_Norway&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;Permafrost melting...&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;h2&gt;Alaska&lt;/h2&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://grist.org/science/alaska-permafrost-thawing-ice-climate-change/&quot; rel=&quot;nofollow noreferrer&quot;&gt;As permafrost thaws, the ground beneath Alaska is collapsing.&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;h2&gt;Iceland&lt;/h2&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.theguardian.com/world/2019/aug/19/iceland-holds-funeral-for-first-glacier-lost-to-climate-change&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iceland holds funeral for first glacier lost to climate change&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;h1&gt;Objective win:&lt;/h1&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Northwest_Passage&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Northwest_Passage&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="14546" LastActivityDate="2022-11-06T18:52:07.433" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24489" PostTypeId="1" CreationDate="2022-11-07T10:57:34.683" Score="3" ViewCount="61" Body="&lt;p&gt;The BRN Shear, which is the denominator of the bulk Richardson number, a parameter used in severe weather forecasting (&lt;a href=&quot;https://www.spc.noaa.gov/exper/soundings/help/shear.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;described here&lt;/a&gt;), is (from &lt;a href=&quot;https://geo.libretexts.org/Bookshelves/Meteorology_and_Climate_Science/Book%3A_Practical_Meteorology_(Stull)/14%3A_Thunderstorm_Fundamentals/14.04%3A_Section_5-&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stull's Practical Meteorology&lt;/a&gt;):&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\mathrm{BRN\;Shear} = 0.5 \cdot (\Delta M)^2$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;With &lt;span class=&quot;math-container&quot;&gt;$\Delta M$&lt;/span&gt; defined as:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\Delta M = [(\Delta U)^2 + (\Delta V)^2]^\frac{1}{2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\Delta U = \overline{U} - U_{SL}\\&#xA;   \Delta V = \overline{V} - V_{SL}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;(&lt;span class=&quot;math-container&quot;&gt;$U$&lt;/span&gt;,&lt;span class=&quot;math-container&quot;&gt;$V$&lt;/span&gt;) are wind components from 0 to 6 km 'weighted' average/mean winds.&lt;/p&gt;&#xA;&lt;p&gt;I would like to ask for some clarification on the &lt;span class=&quot;math-container&quot;&gt;$U_{SL}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$V_{SL}$&lt;/span&gt; terms.  Are these &amp;quot;surface-level&amp;quot; wind components, listed as being from 0 to 0.5 km,  also required to be a weighted average from 0 to 500 m AGL? Or do I only need a 'single' 0.5 km wind acting as the proxy for surface-level winds?&lt;/p&gt;&#xA;" OwnerUserId="27543" LastEditorUserId="6298" LastEditDate="2022-11-08T03:23:16.770" LastActivityDate="2022-11-08T03:23:16.770" Title="Question on BRN Shear" Tags="|meteorology|mesoscale-meteorology|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24490" PostTypeId="1" CreationDate="2022-11-07T13:21:08.363" Score="2" ViewCount="306" Body="&lt;p&gt;I found this stone/crystal when I walked down the street few days ago.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/zbKHO.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zbKHO.jpg&quot; alt=&quot;Pic 1&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Sk1zK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Sk1zK.jpg&quot; alt=&quot;Pic 3&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/I6vHr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/I6vHr.jpg&quot; alt=&quot;Pic 4&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/uNBOs.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uNBOs.jpg&quot; alt=&quot;Pic 5&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/6DKl0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6DKl0.jpg&quot; alt=&quot;Pic 6&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I picked it up since it looks very different with other stones in the area,&lt;/p&gt;&#xA;&lt;p&gt;I am really curious about what stone/crystal it is, but discovered nothing as I have zero knowledge on geology/earth science.&lt;/p&gt;&#xA;&lt;p&gt;Therefore, I hope anyone here can help me to identify what stone it is.&lt;/p&gt;&#xA;&lt;p&gt;TIA&lt;/p&gt;&#xA;" OwnerUserId="27921" LastActivityDate="2022-11-07T13:21:08.363" Title="What stone/crystal is it?" Tags="|geology|mineralogy|crystallography|crystals|" AnswerCount="0" CommentCount="1" ClosedDate="2022-11-07T17:55:46.710" ContentLicense="CC BY-SA 4.0" />
  <row Id="24491" PostTypeId="2" ParentId="24179" CreationDate="2022-11-09T02:27:47.057" Score="1" Body="&lt;p&gt;Partial answer from &lt;a href=&quot;https://www.nature.com/articles/d41586-022-03444-7&quot; rel=&quot;nofollow noreferrer&quot;&gt;an article&lt;/a&gt; in &lt;em&gt;Nature&lt;/em&gt;: militaries are expensive (in terms of carbon emissions) in general. The numbers are opaque because most militaries don't estimate their carbon emissions. However, two militaries do (the US and UK militaries), and the numbers are severe. The US military's emissions per capita is nearly 3x the US's emissions per capita. The UK military emits less, but it's still &amp;gt;3x the UK's emissions per capita as well.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The world’s militaries are heavy emitters of greenhouse gases. No one knows exactly how much; estimates range between 1% and 5% of global emissions, comparable with the aviation and shipping industries (2% each).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;However, the answer is only partial because it doesn't say if emissions increase during a war, and if so by how much.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt; now answered by &lt;a href=&quot;https://www.rfi.fr/en/international-news/20221110-scorched-earth-ukraine-war-takes-heavy-toll-on-climate-too&quot; rel=&quot;nofollow noreferrer&quot;&gt;another source&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Ukraine has started to calculate emissions linked directly and indirectly to the invasion launched by Russia on February 24, a first for a country at war. Fires in buildings, forests and fields sent into the skies 23.8 million tonnes of CO2 equivalent, and the fighting itself 8.9 million tonnes, according to the project called the Initiative on GHG Accounting of War.&lt;/p&gt;&#xA;&lt;p&gt;The displacement of people caused 1.4 million tonnes, said the project created two months into the war, while reconstruction of destroyed infrastructure will cause another 48.7 million tonnes of carbon emissions.&lt;/p&gt;&#xA;&lt;p&gt;The total comes to nearly 83 million tonnes as a direct consequence of the war, now in its eighth month -- compared to around 100 million tonnes produced from all sources by the Netherlands over the same period, according to the initiative.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="27435" LastEditorUserId="27435" LastEditDate="2022-11-10T23:28:05.840" LastActivityDate="2022-11-10T23:28:05.840" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24492" PostTypeId="1" CreationDate="2022-11-09T13:25:47.463" Score="2" ViewCount="90" Body="&lt;p&gt;Given a figure of 1 tonne of CO2e methane emissions, where the CO2e figure is calculated using the 100-year global warming potential, is it possible to do a straight conversion back to tonnes of methane emitted, and then forward again to tonnes of CO2e using the 20-year global warming potential. I.e.:&lt;/p&gt;&#xA;&lt;p&gt;100 year GWP for methane = 28&lt;br /&gt;&#xA;20 year GWP for methane = 84&lt;/p&gt;&#xA;&lt;p&gt;1 tonne CO2e / 28 = 0.0357 tonnes methane emitted&lt;/p&gt;&#xA;&lt;p&gt;0.0357 * 84 = 3 tonnes CO2e at GWP20&lt;/p&gt;&#xA;&lt;p&gt;Or is there more to the GWP100 calculations which aren't purely captured by the factors I've given above?&lt;/p&gt;&#xA;" OwnerUserId="27942" LastActivityDate="2022-11-09T13:25:47.463" Title="Convert methane emissions calculated with GWP100 to GWP20" Tags="|climate-change|carbon|methane|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24493" PostTypeId="1" AcceptedAnswerId="24503" CreationDate="2022-11-09T16:49:18.600" Score="3" ViewCount="74" Body="&lt;p&gt;Last week when I was dealing with the North American Multi-Model Ensemble (NMME) seasonal forecasting system, a variable named “tref,” or Reference Temperature, caught my attention.&lt;br /&gt;&#xA;I read some articles that used reference temperature but couldn’t understand this variable.&#xA;My main question is, what is the definition of the reference temperature? And what is the difference between it and average air temperature?&lt;br /&gt;&#xA;Thank you all.&lt;/p&gt;&#xA;" OwnerUserId="27943" LastEditorUserId="27943" LastEditDate="2022-11-09T16:52:21.357" LastActivityDate="2022-11-12T12:05:34.917" Title="What are the main differences between the reference temperature and the average air temperature?" Tags="|meteorology|climate|temperature|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24495" PostTypeId="1" AcceptedAnswerId="24543" CreationDate="2022-11-09T21:14:06.823" Score="3" ViewCount="262" Body="&lt;p&gt;As a newbie on climate science and meteorology I'm trying to understand the almost logarithmic behavior of CO&lt;sub&gt;2&lt;/sub&gt; concentration on radiation forcing&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$F(c) = A \cdot \ln \frac{c}{c_0}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;and why there is no &amp;quot;saturation&amp;quot; due to further increasing of CO&lt;sub&gt;2&lt;/sub&gt; even when the atmosphere is already totally absorbing as a whole.&lt;/p&gt;&#xA;&lt;p&gt;So far I learned that the air layers which contribute most to outgoing radiation are placed where optical thickness, as measured from TOA, is about 1. Let's say in an undisturbed atmosphere this location is about a height of z=2 (arbitrary units), then a CO&lt;sub&gt;2&lt;/sub&gt; doubling leads to a shift of this layer to about z=3.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/ZbvOg.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZbvOg.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Since this higher layer has usually lower temperature, less energy is irradiated an, therefore, the planet will warm up.&lt;/p&gt;&#xA;&lt;p&gt;This is described also in some detail in &lt;a href=&quot;https://escholarship.mcgill.ca/downloads/db78th05j&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://escholarship.mcgill.ca/downloads/db78th05j&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, other explanations, even mentioned in the cited publication, are based on spectral effects where the wings of the absorption band become more absorbing at higher CO&lt;sub&gt;2&lt;/sub&gt; concentrations:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/f7FZa.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/f7FZa.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Q1: Firstly, I don't understand why this last effect is, because CO&lt;sub&gt;2&lt;/sub&gt; is quite dilute in atmosphere and this effect cannot be due to pressure broadening. What is the reason for absorbing more CO&lt;sub&gt;2&lt;/sub&gt; at the wings when concentration rises up?&lt;/p&gt;&#xA;&lt;p&gt;Q2: secondly, which of the two effects is more relevant to explain the observed log behavior? Are they related in any way or do they just happen to give the same overall result?&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="2470" LastEditDate="2022-11-21T06:32:57.177" LastActivityDate="2023-03-23T00:03:51.970" Title="Why is dependence of radiation forcing on CO2 concentration logarithmic?" Tags="|climate-change|co2|greenhouse-gases|atmospheric-radiation|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="24496" PostTypeId="1" CreationDate="2022-11-10T16:59:02.533" Score="3" ViewCount="119" Body="&lt;p&gt;I want to determine the height of a sine wave for some tidal constituents for which I would use the following equation: ()=cos⁡(−), where H is the amplitude,  is the speed of rotation, t is the time elapsed and  is the phase lag. If I have got the following data for a site, how do I determine the phase lag so that I can calculate Y(t).&lt;/p&gt;&#xA;&lt;p&gt;Constituent M2, Amplitude 3.18, Degrees per hour 28.984, Radians per hour 0.5058, Phase degree 173&lt;/p&gt;&#xA;" OwnerUserId="27949" LastActivityDate="2022-11-10T16:59:02.533" Title="How do I determine the phase lag for a tide" Tags="|tides|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24497" PostTypeId="1" AcceptedAnswerId="24530" CreationDate="2022-11-10T17:40:05.993" Score="8" ViewCount="502" Body="&lt;p&gt;Assume a water planet with an ocean depth of about 200-500 km.&lt;/p&gt;&#xA;&lt;p&gt;Would a very strong ground-quake happening at the very bottom of the planet's ocean floor be able to cause a large tsunami to rise up to the surface of the ocean? If it could, how strong would the ground-quake need to be on the Richter scale in order to do that?&lt;/p&gt;&#xA;" OwnerUserId="27951" OwnerDisplayName="ZanMoon-chan" LastEditorUserId="2470" LastEditDate="2022-11-18T17:26:01.627" LastActivityDate="2022-11-19T09:42:06.290" Title="Is it possible for tsunamis to occur on deep water planets?" Tags="|geophysics|earthquakes|water|planetary-science|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24498" PostTypeId="2" ParentId="24497" CreationDate="2022-11-10T19:54:39.260" Score="8" Body="&lt;p&gt;Tsunami are caused by sudden changes in the sea floor. An earthquake that causes a slump or surge in the seabed can cause a tsunami.&lt;/p&gt;&#xA;&lt;p&gt;Tsunami travel as shallow water waves; they have a wavelength comparable to, or longer than the depth of the water.  A large earthquake can cause rupturing on a scale of hundreds of km, (the &lt;a href=&quot;https://en.wikipedia.org/wiki/2004_Indian_Ocean_earthquake_and_tsunami&quot; rel=&quot;noreferrer&quot;&gt;boxing day quake&lt;/a&gt; caused a rupture of 200km) and so can create a tsunami even in 200km deep water.  Such a tsunami would have a wavelength of hundreds of km and a wave height of perhaps a few cm. So this is not the &lt;em&gt;great wave off Kanagawa&lt;/em&gt; (which was not a tsunami) but it is a true tsunami, and would be undetectable except with high accuracy gauges.&lt;/p&gt;&#xA;&lt;p&gt;If there is no land, the tsunami will circle the planet several times gradually dissipating due to friction.  With no land, it will remain a few cm in amplitude and be of no practical interest.&lt;/p&gt;&#xA;&lt;p&gt;A planet with significant earthquakes will probably have plate tectonics, so the seabed won't be flat, which will have consequences for its velocity. It will move faster over deeper water.&lt;/p&gt;&#xA;" OwnerUserId="9563" LastEditorUserId="13314" LastEditDate="2022-11-11T21:34:51.740" LastActivityDate="2022-11-11T21:34:51.740" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24500" PostTypeId="2" ParentId="24179" CreationDate="2022-11-11T18:20:17.270" Score="1" Body="&lt;p&gt;One report, &lt;em&gt;&lt;a href=&quot;https://www.downtoearth.org.in/news/pollution/cop27-russian-invasion-of-ukraine-released-8-million-tonnes-carbon-till-september-says-report-85905&quot; rel=&quot;nofollow noreferrer&quot;&gt;COP27: Russian invasion of Ukraine released 8 million tonnes carbon till September, says report&lt;/a&gt;&lt;/em&gt; claims 8 Mt of carbon dioxide equivalent have been emitted from February 2022 to September 2022.&lt;/p&gt;&#xA;&lt;p&gt;Of this, 1.4 Mt of GHG emissions has been associated with just the movement of refugees as a result of the Russian invasion of Ukraine.&lt;/p&gt;&#xA;&lt;p&gt;These estimates have considered &amp;quot;troop movements, fuel consumption, and military aircraft and also impact of explosives and ammunition in Ukraine&amp;quot;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;At least 6,215 fires spread over a total area of 486,162 hectares were caused by the ammunition and bombs during the seven months of the study period or the first 214 days of the war.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It is claimed that &amp;quot;from February 24 onward, 224,956 explosive devices were fired by Russian troops&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;It is also estimated that 48.7 Mt of carbon dioxide equivalent will be made during reconstruction.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The war also caused damage to 497 water management facilities in Ukraine. According to a World Bank assessment, it would cost 7.71 billion Euros for the restoration of irrigation, drainage, and hydro-technical structures over a 10-year period.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;What no-one has yet mentioned is the amount of carbon dioxide that will be released in the future as a result of replacement armaments being manufactured to replace the ones used during the conflict.&lt;/p&gt;&#xA;&lt;p&gt;Additional &lt;a href=&quot;https://e360.yale.edu/features/ukraine-russia-war-environmental-impact&quot; rel=&quot;nofollow noreferrer&quot;&gt;environmental impacts&lt;/a&gt; from the war include:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Some 30 percent of the country’s protected areas, covering 3 million&#xA;acres (1.214 Mha), have been ­­bombed, polluted, burned, or hit by&#xA;military maneuvers;&lt;/li&gt;&#xA;&lt;li&gt;Rare steppe and island ecosystems in the south have been pummeled,&#xA;threatening endemic grassland plants and insects;&lt;/li&gt;&#xA;&lt;li&gt;Rivers across the Donbas conflict zone in the east are being polluted&#xA;by wrecked industrial facilities, sewage works, and overflowing coal&#xA;mines;&lt;/li&gt;&#xA;&lt;li&gt;The possibility of an upsurge in uncontrolled logging of ancient&#xA;forests in the Carpathian Mountains;&lt;/li&gt;&#xA;&lt;li&gt;The listing of 20 rare steppe species that they believe may disappear&#xA;due to the war;&lt;/li&gt;&#xA;&lt;li&gt;Peat in the Chernobyl exclusion zone is continuing to smolder as a&#xA;result of the war;&lt;/li&gt;&#xA;&lt;li&gt;Particularly in the Donbas region, &amp;quot;Many industrial plants are&#xA;damaged or abandoned; wrecked sewage works gush their contents into&#xA;rivers; damaged pipelines are filling wetlands with oil; and toxic&#xA;military scrap is spread across the land ... No one has done any research and probably won’t for many years&amp;quot;;&lt;/li&gt;&#xA;&lt;li&gt;A particular concern is the many coal mines abandoned after 2014.&#xA;With pumping of water halted, they have so far released some 650,000&#xA;acre-feet (80.1763 million cubic meters) of polluted mine water into&#xA;the environment;&lt;/li&gt;&#xA;&lt;li&gt;A few of the flooded mines are radiological hazards. For instance,&#xA;Soviet scientists carried out a controlled atomic explosion at the&#xA;Yunkom Mine in Donetsk in 1979. The waste remains underground. Since&#xA;the pumps were turned off in 2018, the mine has overflowed into&#xA;nearby underground water reserves used for drinking;&lt;/li&gt;&#xA;&lt;li&gt;Many also fear the long-term toxic legacy of the giant Azovstal&#xA;steelworks in Mariupol, which was bombarded for many weeks before&#xA;falling to the Russians in May. The works was already a notorious&#xA;defiler of local soils, air, and rivers. The Russian bombardment&#xA;could have released tens of thousands of tons of hydrogen sulfide&#xA;into the Sea of Azov with unknown ecological consequences.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-11-11T18:20:17.270" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24502" PostTypeId="1" CreationDate="2022-11-12T10:22:20.043" Score="3" ViewCount="44" Body="&lt;p&gt;As far as I understand, wind is stochastic on small scale. Then wouldn't that mean, since the function is not Riemann integrable, Fourier Transform cannot be used? What is the reason that climate researchers can use Fourier Transform successfully, while, for example, stock market analysts fail to do so?&lt;/p&gt;&#xA;&lt;p&gt;Please correct me. Any feedback is appreciated.&lt;/p&gt;&#xA;" OwnerUserId="27957" LastActivityDate="2022-11-12T10:22:20.043" Title="Mathematically speaking, why can we use Fourier Transform when studying wind?" Tags="|wind|mathematics|turbulence|" AnswerCount="0" CommentCount="3" ClosedDate="2022-11-18T07:38:46.020" ContentLicense="CC BY-SA 4.0" />
  <row Id="24503" PostTypeId="2" ParentId="24493" CreationDate="2022-11-12T11:47:05.307" Score="2" Body="&lt;p&gt;I have the same question and found a satisfying answer recently.&lt;/p&gt;&#xA;&lt;p&gt;The reference state, including wind, temperature and pressure, is a dynamically-steady state to the equation of motion of the atmosphere.  It is a steady-state solution only when the flow is adiabatic and inviscid (no external forcings).  More specifically, the reference state is:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;zonally uniform,&lt;/li&gt;&#xA;&lt;li&gt;vertically in hydrostatic balance, and&lt;/li&gt;&#xA;&lt;li&gt;meridionally in gradient-wind balance&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;everywhere in the domain&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Although scientists knew there exists such state, only &lt;a href=&quot;https://journals.ametsoc.org/view/journals/atsc/67/12/2010jas3503.1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nakamura and Zhu (2010)&lt;/a&gt; and &lt;a href=&quot;https://rmets.onlinelibrary.wiley.com/doi/10.1002/qj.2518&quot; rel=&quot;nofollow noreferrer&quot;&gt;Methven and Berrisford (2015)&lt;/a&gt; provided numerical methods to calculate such reference state, given any instantaneous atmospheric state.  This is equivalent to a conservative rearrangement, schematically shown below:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/z0ZC7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/z0ZC7.png&quot; alt=&quot;conservative rearrangement&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This rearrangement conserve mass between any two isentrops and circulation along each PV contour, which can be called conservative zonalization.&lt;/p&gt;&#xA;&lt;p&gt;Before these numerical algorithms were proposed, most people use Eulerian average of atmospheric state, like long-term time mean or zonal mean, to give a diffuse estimate of this reference state.  As a result, the jet and temperature front in the averaged state are usually weaker than those in the reference state.&lt;/p&gt;&#xA;&lt;p&gt;Another reference state, motionless and horizontally flat pressure surface in hydrostatic balance, is also a steady-state solution to the (adiabatic and inviscid) equation of motion.  However, it is a trivial resting state that does not have circulation at all.  Therefore, we may not be interested in this resting reference state.&lt;/p&gt;&#xA;" OwnerUserId="11261" LastEditorUserId="11261" LastEditDate="2022-11-12T12:05:34.917" LastActivityDate="2022-11-12T12:05:34.917" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24504" PostTypeId="2" ParentId="20437" CreationDate="2022-11-12T13:17:15.427" Score="1" Body="&lt;p&gt;Maybe you can try to understand Rossby wave by appreciating the analogy between (internal) gravity wave and Rossby wave.&lt;/p&gt;&#xA;&lt;p&gt;Two distinct features of geofluid are stratification and (differential) rotation.  Stratification, or vertical variation of density, produces internal gravity wave.  Similarly, differential rotation (or variation of rotation), gives rise to (barotropic) Rossby wave.  Their difference can not be easily identified by observing the tracer (temperature, density etc.) field in the figure below, without knowing the coordinates.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XHmHo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XHmHo.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Vertical decreasing density with altitude gives a fluid parcel a restore force when it is displaced upward/downward; Likewise, meridionally increasing rotation also gives a restore force when a parcel is displaced northward/southward.  Therefore, a fluid parcel cannot move freely in the vertical and meridional directions due to these restore forces (you probably already notice that the contours of many things  on rotating planets are horizontal lines or zonal lines).  Such restoring forces actually generates respectively the internal gravity wave and Rossby wave.  The gradient of potential temperature (density of mass), as well as the gradient of potential vorticity (density of rotation) here is a measurement of the restoring force.&lt;/p&gt;&#xA;&lt;p&gt;The internal gravity wave can bring lighter (heavier) fluid downward (upward).  Similarly, the Rossby wave brings colder (warmer) fluid equatorward (poleward) and thus affects the weather.  In addition, the Rossby wave also squeezes the atmosphere so that the water vapor condenses into rainfall, affecting the weather.&lt;/p&gt;&#xA;" OwnerUserId="11261" LastEditorUserId="11261" LastEditDate="2022-11-13T12:34:13.187" LastActivityDate="2022-11-13T12:34:13.187" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24505" PostTypeId="2" ParentId="9874" CreationDate="2022-11-12T16:10:45.577" Score="0" Body="&lt;p&gt;This is not a valid diagnostic equation.  The vertical velocity &lt;span class=&quot;math-container&quot;&gt;$\omega$&lt;/span&gt; is defined in vertical pressure &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; coordinate as &lt;span class=&quot;math-container&quot;&gt;$\omega = Dp/Dt$&lt;/span&gt;.  As a result, all the equations you used should be in pressure coordinate.&lt;/p&gt;&#xA;&lt;p&gt;Then the continuity equation&#xA;&lt;span class=&quot;math-container&quot;&gt;$$D\rho/Dt=-\rho\nabla\cdot\vec u$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;will change to&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\nabla_p\cdot\vec u=\partial_x u+\partial_y v+\partial_p \omega=0$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Also, density &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; in pressure coordinate becomes a constant &lt;span class=&quot;math-container&quot;&gt;$1/g$&lt;/span&gt;.  You should use everything in pressure coordinate for a diagnostic equation of &lt;span class=&quot;math-container&quot;&gt;$\omega$&lt;/span&gt;.&lt;/p&gt;&#xA;" OwnerUserId="11261" LastEditorUserId="11261" LastEditDate="2022-11-13T13:19:48.457" LastActivityDate="2022-11-13T13:19:48.457" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24506" PostTypeId="2" ParentId="9271" CreationDate="2022-11-12T16:40:33.140" Score="1" Body="&lt;p&gt;Mathmatically, the Sawyer–Eliassen equation is an second-order partical differential equation of the form:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial}{\partial y}\left(A\frac{\partial \psi}{\partial y}+B\frac{\partial\psi}{\partial z}\right)+\frac{\partial}{\partial z}\left(B\frac{\partial\psi}{\partial y}+C\frac{\partial\psi}{\partial z}\right)=F$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;When the condition &lt;span class=&quot;math-container&quot;&gt;$AC-B^2&amp;gt;0$&lt;/span&gt; (equivalent to yours) is met, it is elliptic equation that can be solved numerically.  Physically, the solution is an asymptotic steady-state response to the (QG) forcing &lt;span class=&quot;math-container&quot;&gt;$F$&lt;/span&gt; you identified.  That is, the frontal structure will evolve towards a steady state in balance to &lt;span class=&quot;math-container&quot;&gt;$F$&lt;/span&gt;.  If the condition is not met, SE equation cannot be solved numerically (iteration does not converge).  This means that any small perturbation of fluid parcel will accelerate its departure from its initial location.&lt;/p&gt;&#xA;&lt;p&gt;It is not too hard to prove that the elliptic condition &lt;span class=&quot;math-container&quot;&gt;$AC-B^2&amp;gt;0$&lt;/span&gt; is equivalent to &lt;span class=&quot;math-container&quot;&gt;$fP&amp;gt;0$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$P$&lt;/span&gt; is potential vorticity and &lt;span class=&quot;math-container&quot;&gt;$f$&lt;/span&gt; the Coriolis parameter.  The latter means symmetric stable (PV and f have the same sign).  So symmetric stable means we have steady-state solution to the Sawyer–Eliassen equation.  Instability means we cannot get the numerical solution iteratively as it diverges, which could be understood as a free convection rather than a QG forced upward motion.&lt;/p&gt;&#xA;" OwnerUserId="11261" LastActivityDate="2022-11-12T16:40:33.140" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24507" PostTypeId="2" ParentId="24254" CreationDate="2022-11-12T17:16:42.710" Score="4" Body="&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/s41550-021-01487-w&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;Solar wind contributions to Earth’s oceans&quot;&gt;About 30,000 tonnes&lt;/a&gt; of extraterrestrial material arrives on earth every year, mostly in the form of submillimeter dust. Unfortunately, these &lt;a href=&quot;https://en.wikipedia.org/wiki/Micrometeorite&quot; rel=&quot;nofollow noreferrer&quot;&gt;micrometeorites&lt;/a&gt; are pretty dry.  The wettest meteors &lt;a href=&quot;https://www.nature.com/articles/s41550-021-01487-w&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;Solar wind contributions to Earth’s oceans&quot;&gt;might be 10% water&lt;/a&gt; by weight, but a &lt;a href=&quot;https://books.google.ca/books?id=lDbMELpF8EcC&amp;amp;pg=PA78&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;Comets and the Origin and Evolution of Life&quot;&gt;generous estimate&lt;/a&gt; of the average amount of water in micrometeorites would be 4%, so the earth is probably not receiving more than about a 1000 tonnes of water per year, and likely less.&lt;/p&gt;&#xA;&lt;p&gt;The earth loses about &lt;a href=&quot;https://earthscience.stackexchange.com/questions/9488/how-much-water-is-the-atmosphere-losing-to-space&quot; title=&quot;How much water is the atmosphere losing to space?&quot;&gt;10,000 tonnes of water annually&lt;/a&gt;, far more than it receives from space.&lt;/p&gt;&#xA;" OwnerUserId="27775" LastActivityDate="2022-11-12T17:16:42.710" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24509" PostTypeId="2" ParentId="23922" CreationDate="2022-11-13T13:03:56.090" Score="1" Body="&lt;p&gt;From the code you provided, you used finite difference approximation to the differential expressions.  That is the root of the difference.  When you use finite difference schemes (here centered differencing), you have implicitly neglected the higher-order terms in Taylor series.&lt;/p&gt;&#xA;&lt;p&gt;Generally, a differential term can be sometimes written in different forms.  These different forms give somewhat different results when they are discretized.  A well-known example is:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$u\frac{du}{dx}=\frac{1}{2}\frac{du^2}{dx}$$&lt;/span&gt;&#xA;However, if you using centered differencing, you cannot prove:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$u_i\frac{u_{i+1}-u_{i-1}}{2\Delta x}=\frac{1}{2}\frac{u_{i+1}^2-u_{i-1}^2}{2\Delta x}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;because higher-order terms are dropped out.  So you have to properly choose your expression for discretization.  For diagnostic purpose, such difference can generally be ignored, as it is due to your finite difference scheme.&lt;/p&gt;&#xA;" OwnerUserId="11261" LastActivityDate="2022-11-13T13:03:56.090" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24510" PostTypeId="2" ParentId="12" CreationDate="2022-11-13T13:32:54.397" Score="1" Body="&lt;p&gt;First of all, Rossby wave forms not only in the ocean, but also in the atmosphere (even in magma).  It is a feature of fluids on rotating planets.&lt;/p&gt;&#xA;&lt;p&gt;Maybe you can try to understand Rossby wave by appreciating the analogy between (internal) gravity wave and Rossby wave.&lt;/p&gt;&#xA;&lt;p&gt;Two distinct features of geofluid are stratification and (differential) rotation.  Stratification, or vertical variation of density, produces internal gravity wave.  Similarly, differential rotation (or variation of rotation), gives rise to (barotropic) Rossby wave.  Their difference can not be easily identified by observing the tracer (temperature, density etc.) field in the figure below, without knowing the coordinates.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/XHmHo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XHmHo.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Vertical decreasing density with altitude gives a fluid parcel a restore force when it is displaced upward/downward; Likewise, meridionally increasing rotation also gives a restore force when a parcel is displaced northward/southward.  Therefore, a fluid parcel cannot move freely in the vertical and meridional directions due to these restore forces (you probably already notice that the contours of many things  on rotating planets are horizontal lines or zonal lines).  Such restoring forces actually generates respectively the internal gravity wave and Rossby wave.  The gradient of potential temperature (density of mass), as well as the gradient of potential vorticity (density of rotation) here is a measurement of the restoring force.&lt;/p&gt;&#xA;" OwnerUserId="11261" LastActivityDate="2022-11-13T13:32:54.397" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24512" PostTypeId="1" CreationDate="2022-11-13T20:16:55.120" Score="1" ViewCount="23" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9ihq0.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9ihq0.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bvenp.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bvenp.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rrWAM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rrWAM.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Illustration showing the type of transform fault and the length change of transform fault.&lt;/p&gt;&#xA;&lt;p&gt;Why does the length change of the transition fault between the subduction zones appear as illustrated? I don't understand&lt;/p&gt;&#xA;" OwnerUserId="22990" LastActivityDate="2022-11-13T20:16:55.120" Title="Length change of transform fault" Tags="|structural-geology|transform-fault|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24513" PostTypeId="1" CreationDate="2022-11-14T03:28:49.427" Score="4" ViewCount="42" Body="&lt;p&gt;I am not a scientist but I am interested in the effects of global warming on the envirand would like to read more in a layman form.&#xA;I have read where global warming - hotter earth surface temperature and green house atmosphere effects have lead to increased evaporation, which lead to lower denser heavier clouds that cause heavier quicker rain that can result in flooding and flash flooding.&#xA;This seems to make sense and I after more scientific/theories like this that give environmental changes apart from icecap melting and sea level rises that are well explained in layman terms.&lt;/p&gt;&#xA;" OwnerUserId="24806" LastActivityDate="2022-11-14T03:28:49.427" Title="is there any site a layman can understand excess rain (floods) and earth warming" Tags="|climate|climate-models|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24514" PostTypeId="2" ParentId="24156" CreationDate="2022-11-14T13:43:30.640" Score="0" Body="&lt;p&gt;Here you can find an explanation to calculate the surface relative humidity:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://confluence.ecmwf.int/pages/viewpage.action?pageId=171411214&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://confluence.ecmwf.int/pages/viewpage.action?pageId=171411214&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27968" LastActivityDate="2022-11-14T13:43:30.640" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24515" PostTypeId="1" CreationDate="2022-11-15T00:43:40.857" Score="2" ViewCount="38" Body="&lt;p&gt;It's well known that the Great Lakes produce large amounts of precipitation in the Fall.  When cold polar air moves over the lakes it causes large amounts of relatively warm moist air to rise, condense and fall as either rain or snow on shore.&lt;/p&gt;&#xA;&lt;p&gt;Under which conditions would you expect to find the MOST precipitation?&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;A polar air mass of 0 degrees centigrade moving over a great lake that has a water temperature of 10 degrees.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;OR&lt;/p&gt;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;A polar air mass of -5 degrees centigrade moving over a great lake that has a water temperature of 5 degrees.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="27972" LastActivityDate="2022-11-15T00:43:40.857" Title="Under which conditions would you see the MOST lake effect precipitation?" Tags="|meteorology|geophysics|geochemistry|earth-system|cloud-microphysics|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24516" PostTypeId="1" CreationDate="2022-11-15T14:38:15.757" Score="1" ViewCount="18" Body="&lt;p&gt;I have two timeseries one for a daily rainfall and another one for a daily storm surge height. I would like to calculate the probability of a certain rainfall depth with a certain storm surge height. Meaning the joint probability of rainfall 'x' happening with 'y' storm surge height. I understand there is an advanced way of computing that with copulas but is there a simpler way of computing that?&lt;/p&gt;&#xA;" OwnerUserId="27888" LastActivityDate="2022-11-15T14:38:15.757" Title="compute joint probability of two variables with out using copulas" Tags="|rainfall|statistics|storms|flooding|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24519" PostTypeId="1" CreationDate="2022-11-16T01:23:41.187" Score="3" ViewCount="53" Body="&lt;p&gt;I am planning to publish a paper related in Geoscience/Geophysics/Seismology within scope of &lt;strong&gt;Machine Learning/AI&lt;/strong&gt; in particular. Is there any Journal that provide free article publishing for postgraduate students? Low publishing fees should be fine as well.&lt;/p&gt;&#xA;" OwnerUserId="27982" LastActivityDate="2022-11-16T08:42:31.060" Title="Is there any free indexed journal that Geoscience students can publish?" Tags="|geophysics|seismology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24521" PostTypeId="2" ParentId="24421" CreationDate="2022-11-16T05:32:48.103" Score="1" Body="&lt;p&gt;If memory serves me well, the historical records point to sparse forests. I'm afraid I can't locate Patrick Wyman's excellent Tides of History podcast episodes on this, but I can offer the high level explanations.&lt;/p&gt;&#xA;&lt;p&gt;Several factors play into this. One is moisture (i.e. rainfall). You can use that and what an &amp;quot;undeveloped&amp;quot; (i.e. non-plantation) landscape look like with comparable climates as a relatively safe predictor of what an environment might have looked like in the absence of monoculture agriculture.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4fmKS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4fmKS.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Another important factor is the presence or absence of grazers like deer or elephants that like to munch on tree saplings. (The way to grow a forest in a place like Scotland is to simply fence them out.)&lt;/p&gt;&#xA;&lt;p&gt;Yet another factor is the use of fire by humans and ancestors for one reason or another. This is typically to clear hunting fields and growing fields. Fires tend to kill tree saplings, and repeated fires tend to produce grasslands, which are fire-adapted ecosystems.&lt;/p&gt;&#xA;&lt;p&gt;The trees that survive fires are usually fast burning (allows the fire to move on before the tree actually burns), light tolerant (no canopy over them), and accommodating to grassland plants (sparse canopy that lets sunlight through), with some room for forest edge species that have denser canopy.&lt;/p&gt;&#xA;&lt;p&gt;The last factor is whether humans are chopping down trees for one reason or another. We've been doing that in authoritarian societies since at least the invention of metallurgy. (Non-authoritarian ones like native Americans would use whole trees to make canoes and not much else.)&lt;/p&gt;&#xA;&lt;p&gt;Also, the archeological record in Europe suggests that, before its trees got chopped down, there were actually two societies.&lt;/p&gt;&#xA;&lt;p&gt;One was of humans that survived on a combination of hunting, gathering, and no doubt pre-agricultural activities that would have looked like loose herding or farming to a modern eye. Picture a modern Mayan village, if you will, with people living among free ranging dogs and chickens, broadcast sowing multi-crop fields for cereal in select fields cleared using fire, and otherwise living in a forest that they extract all sorts of yields from.&lt;/p&gt;&#xA;&lt;p&gt;The other preferred to live in areas with black soil. They were far more agricultural (they settled land for that very purpose), and no doubt far more warrior-like. They eventually took over so it's reasonable to assume that they introduced plowing eventually.&lt;/p&gt;&#xA;&lt;p&gt;Put together, it's not a BC-style rainforest. Rather, it's more like Brazil's north east or Argentina's north with a bit less tree cover. Think generally sparse, with some areas that sport full blown forests (the water drains somewhere...), others that sport long stretches of quasi-cleared grasslands (the water that drains comes from somewhere...), and yet others with completely cleared grasslands by pre-agricultural societies that will soon commence plowing activities.&lt;/p&gt;&#xA;&lt;p&gt;This would have made an ideal habitat for bisons, rhinos, and mammoths that would have feasted on tasty crops when our ancestors began growing those. Those animals got hunted to extinction for an excellent reason: the last thing you want in your cereal patch is a mammoth. This is eerily similar to why rhinos and elephants get hunted in the modern era.&lt;/p&gt;&#xA;" OwnerUserId="6375" LastEditorUserId="6375" LastEditDate="2022-11-16T05:38:39.250" LastActivityDate="2022-11-16T05:38:39.250" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24522" PostTypeId="2" ParentId="24519" CreationDate="2022-11-16T08:42:31.060" Score="2" Body="&lt;p&gt;There has been a surge of &lt;a href=&quot;https://en.wikipedia.org/wiki/Diamond_open_access&quot; rel=&quot;nofollow noreferrer&quot;&gt;diamond open access&lt;/a&gt; (the best practice IMHO) geoscience journals recently, beginning with the pioneer Volcanica in my field (volcanology), and then followed by Tektonika (tectonics/structural geology), Geomorphica (geomorphology), Sedimentologika (sedimentology), among others. In your field, there is... &lt;a href=&quot;https://seismica.library.mcgill.ca/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Seismica&lt;/a&gt;! Their &lt;a href=&quot;https://seismica.library.mcgill.ca/policies#scope&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scope page&lt;/a&gt; includes:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Theoretical and computational seismology:&lt;/strong&gt; advances in seismology&#xA;driven by numerical modeling including high-performance computing, by&#xA;forward and inverse theories, uncertainty analysis and machine&#xA;learning.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;If cost (and open access!) are more important than impact factor to you, I'd encourage you to publish there.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2022-11-16T08:42:31.060" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24523" PostTypeId="2" ParentId="23740" CreationDate="2022-11-16T10:26:49.330" Score="0" Body="&lt;p&gt;You shall not forget that also the Arabian plate is subducting below the Eurasian plate.&lt;/p&gt;&#xA;&lt;p&gt;In fact, the mutual interactions between the two has been investigated by many researcher; for example you can find an in-depth discussion in the PhD thesis &lt;a href=&quot;https://www.fundaciongarciasineriz.es/2016/03/10/xxiia132016/&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Central Asia collision zone: numerical modelling of the lithospheric structure and the present-day kinematics&lt;/a&gt; (Lavinia Tunini, 2015) [in Spanish]&lt;/p&gt;&#xA;&lt;p&gt;In short: greatest mountain ranges are uplift where there is subduction. The fact that the Indian plate and the Arabian plate are subducting, generates mountian ranges. The fact that they are one next to the other, surely has a mutual impact.&lt;/p&gt;&#xA;&lt;p&gt;And we are discussing things moving on a spherical shell, as soon as you rotate and up/downlift something, somewhere in the world, the complete stresses on the sperical shell are perturbed.&lt;/p&gt;&#xA;" OwnerUserId="5887" LastEditorUserId="6298" LastEditDate="2023-04-15T14:14:06.423" LastActivityDate="2023-04-15T14:14:06.423" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24524" PostTypeId="1" AcceptedAnswerId="24570" CreationDate="2022-11-17T03:34:25.840" Score="2" ViewCount="201" Body="&lt;p&gt;I have been doing some quality analysis on soil analytical data that I've gathered from some environmental impact assessments.  Many of the values for base saturation percentage are well over 100% (some over 500%).  Since I am not a soil scientist, I was hoping that someone could confirm for me whether or not it is possible for base saturation percentage to be greater than 100%?&lt;/p&gt;&#xA;&lt;p&gt;It's my understanding that base saturation percentage is &lt;a href=&quot;https://en.wikipedia.org/wiki/Cation-exchange_capacity#Base_saturation&quot; rel=&quot;nofollow noreferrer&quot;&gt;the proportion of the cation exchange capacity (CEC) made up by the base cations (sodium, magnesium, potassium and calcium)&lt;/a&gt;.  As &lt;a href=&quot;https://www.clemson.edu/public/regulatory/ag-srvc-lab/soil-testing/cec-calculations.html#:%7E:text=To%20calculate%20the%20percent%20base,Multiply%20the%20result%20by%20100%25.&quot; rel=&quot;nofollow noreferrer&quot;&gt;base saturation is a fraction of the total CEC&lt;/a&gt;, I don't see how it would be possible for the base saturation percentage to ever be greater than 100%.&lt;/p&gt;&#xA;" OwnerUserId="27981" LastEditorUserId="27981" LastEditDate="2022-11-17T15:12:03.647" LastActivityDate="2022-11-28T18:35:22.570" Title="Can base saturation percentage be greater than 100%?" Tags="|biogeochemistry|soil-science|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24525" PostTypeId="1" AcceptedAnswerId="24538" CreationDate="2022-11-17T08:18:19.380" Score="1" ViewCount="68" Body="&lt;p&gt;If the mountains were levelled and salt removed would the country experience as much rainfall?&lt;/p&gt;&#xA;&lt;p&gt;Context&#xA;Damp in houses:&#xA;Salt absorbs moisture: think of plaster walls that grow mould from proximity to a wall with hygroscopic minerals - ie salt. Damp is a common problem in the UK where it is not in other countries even more north of the hemisphere and should be colder. There are other reasons from water ingress, indoor humidity and render bridging dpc but salt concentrates the most absorption.&lt;/p&gt;&#xA;&lt;p&gt;Excess salt causea edema also in the body.&lt;/p&gt;&#xA;&lt;p&gt;Salt sits at the bottom of oceans. It is easily dissolved in water.&lt;/p&gt;&#xA;&lt;p&gt;I'm asking, if the salt were somehow removed entirely from the country would it recieve as much rain long term.&lt;/p&gt;&#xA;&lt;p&gt;Additional context. Initially the world movement of water causing rainfall is dictated by magnetic waves of the moon on the sea, climate variations between regions, temperature and dew point and other elements but trapped moisture within small pockets of land evaporates or sinks and that gradual release of moisture in the air from salt or other water traps rise up and recirculates cumulatively potentially leading to more rain. Eg: Wales is wetter than Sussex.&lt;/p&gt;&#xA;" OwnerUserId="27990" LastEditorUserId="2470" LastEditDate="2022-11-20T09:37:47.773" LastActivityDate="2022-11-21T09:35:01.367" Title="Is good rainfall in the UK the result of being a small island surrounded by large moving seas, having mountains and trapped salt" Tags="|climate|rainfall|humidity|" AnswerCount="1" CommentCount="8" ClosedDate="2022-11-20T20:20:58.710" ContentLicense="CC BY-SA 4.0" />
  <row Id="24526" PostTypeId="1" AcceptedAnswerId="24708" CreationDate="2022-11-17T11:06:40.270" Score="2" ViewCount="52" Body="&lt;p&gt;My question is about World Magnetic (WMM) and International Geomagnetic Reference Field (IGRF) models. It is well known that to a first approximation, earth magnetic field is a field of dipole. It corresponds to the first term in the Gaussian series. Is it possible to estimate the error of such an approximation? I am interested only in dipole approximation, i. e. is it possible to obtain an error of given (first) Gauss coefficient, or is there any studies where the dipole model investigated, with estimation of uncertainties?&lt;/p&gt;&#xA;" OwnerUserId="27991" LastEditorUserId="27991" LastEditDate="2022-11-17T11:22:25.317" LastActivityDate="2023-01-01T17:21:51.220" Title="Earth magnetic field, WMM/IGRF" Tags="|geomagnetism|field-measurements|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24527" PostTypeId="2" ParentId="21148" CreationDate="2022-11-17T18:26:00.437" Score="1" Body="&lt;p&gt;larger tornado's do have discernible eyes, and I fail to understand why people keep popping up online trolling cyclones by saying they never have eyes at the center. two eyewitnesses have passed through these phenomenon and lived to testify that they are very real. tornados are vortices, like hurricanes, or whirlpools, and all these things have hollow centers, around which they rotate. the Joplin Missouri tornado in 2011 was a mile wide, with a 300 yard eye. ask survivor from the Wal Mart in that things path, they'll tell you about the full minute of silence and stillness as they sheltered inside, and the thing past overhead.&lt;/p&gt;&#xA;" OwnerUserId="27992" LastActivityDate="2022-11-17T18:26:00.437" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24528" PostTypeId="1" CreationDate="2022-11-17T19:16:43.173" Score="2" ViewCount="27" Body="&lt;p&gt;My question is regarding the following statement given &lt;a href=&quot;https://www.slb.com/-/media/files/oilfield-review/p48-56#:%7E:text=Oilfield%20Anisotropy%3A%20Its%20Origins%20and%20Electrical%20Characteristics%20Across,fall.%20Seismic%20reflectors%20appear%20at%20the%20wrong%20depth.&quot; rel=&quot;nofollow noreferrer&quot;&gt;in this paper&lt;/a&gt; on page 51. It reads,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Fundamental to both anisotropy and heterogeneity is the concept of&#xA;scale. Whether anisotropy and heterogeneity are perceived depends on&#xA;sample size and sampling resolution. In fact, to say &amp;quot;this rock is&#xA;anisotropic&amp;quot; is almost meaningless unless scale is also defined-that&#xA;is, both the size of the sample and the resolution of the sampling&#xA;method.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Can you help me understand? A concrete example would help me. Say a rock core 7 inches (177.8 mm) in diameter and 12 inches (304.8 mm) in length. It has visible bedding on the mm to cm scale running parallel to its length. Several plugs (20 say) are cut from about the core’s diameter. Let’s say the plug dimension is 1-inch (25.4 mm) diameter x 2-inch (50.8 mm) length. The plugs’ permeabilities are measured, from which the 2x2 permeability tensor for the diametral plane of the parent core is characterized. Let’s say the max-to-min ratio of the two principal values of this 2x2 tensor is 3. How should the size of the sample and the resolution of the sampling method for this result be stated? (If more information is needed, what information is needed?)&lt;/p&gt;&#xA;&lt;p&gt;*Can the community post the relevant tags for this question/post for me?&lt;/p&gt;&#xA;" OwnerUserId="538" LastEditorUserId="2470" LastEditDate="2022-11-18T17:36:13.507" LastActivityDate="2022-11-18T17:36:13.507" Title="On defining a scale for anisotropy" Tags="|geology|measurements|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24529" PostTypeId="1" CreationDate="2022-11-17T21:25:08.417" Score="1" ViewCount="22" Body="&lt;p&gt;In World Building I asked a question about the climate of an hypothetical planet.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://worldbuilding.stackexchange.com/questions/159199/climate-in-an-hypothetical-planet#comment499721_159199&quot;&gt;There&lt;/a&gt; &lt;a href=&quot;https://worldbuilding.stackexchange.com/users/69877/vogon-poet&quot;&gt;Vogon poet&lt;/a&gt; said that&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Everyone above 10° latitude will be in permanent drought&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Considering that there were no Milankovitch cycles (with a year of exactly 31104000 seconds (360 Earth days) and a day of exactly 86400 seconds (24 hours) and a circular orbit with a distance between the surface of Earth and the Sun's surface equal to the harmonic mean of the current distance), Earth was an oblate spheroid (with the same mass) with a perfectly smooth surface (only allowing for moderate variance due to fauna, flora and civilisation), there were only 2 bodies in the universe Earth and a Sun (a perfect ball with smooth surface and uniform density with the same amount of radiation).&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;What would be the least equatorial bulge consistent with modest amounts of water in polar regions?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="17030" LastEditorUserId="2470" LastEditDate="2022-11-18T17:41:07.020" LastActivityDate="2022-11-18T17:41:07.020" Title="Least equatorial ( and tidal) bulge consistent with modest amounts of water in polar regions" Tags="|geology|geophysics|plate-tectonics|models|geodynamics|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24530" PostTypeId="2" ParentId="24497" CreationDate="2022-11-18T04:31:05.670" Score="5" Body="&lt;p&gt;To add a bit of a quantitative perspective to James' answer.&lt;/p&gt;&#xA;&lt;p&gt;Tsunamis occur in the wake of large earthquakes. They grow in amplitude because the speed of a water gravity wave is influenced by water depth, causing the wave to 'pile up'. In particular, if the wavelength is (much) greater than the depth of the water, the speed at which a wave will travel is roughly:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$v \sim \sqrt{gd}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where v is the speed, g is the gravity, and d is the depth. So by keeping the dimensions consistent as a wave enter shallower water the wave length (L) is squished proportionally to the change in speed and amplitude (A) grows accordingly:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ \dfrac{A_1}{A_2} \sim \dfrac{L_1}{L_2} \sim \dfrac{v_2}{v_1} $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;such that&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$A_2 \sim A_1 \sqrt{\dfrac{d_1}{d_2}}. $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;h3&gt;Plugging some numbers in:&lt;/h3&gt;&#xA;&lt;p&gt;So even for an earthquake that displaces water over say 500km (e.g. &lt;span class=&quot;math-container&quot;&gt;$M_w9.1$&lt;/span&gt; Tohoku earthquake). If the water changes in depth from 500km to 200km (as OP asks), the change in height will only be a factor of:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$A_2 \sim A_1 \sqrt{\dfrac{500km}{200km}} \sim 1.5A_1.$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;JeopardyTempest asks, what if the water got as shallow as 20km then:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$A_2 \sim A_1 \sqrt{\dfrac{500km}{20km}} \sim 5A_1.$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;h3&gt;How big?&lt;/h3&gt;&#xA;&lt;p&gt;Now &lt;span class=&quot;math-container&quot;&gt;$A_1$&lt;/span&gt; (the original wave height) is generally comparable to the average vertical displacement from the earthquake. On earth, the plate boundary configuration is such that the largest earthquakes occur on shallow-dipping subduction zones such that the corresponding average vertical deformation would rarely exceed 1 meter even in the largest earthquakes. Tohoku for instance had a maximum sea floor displacement of tens of meters (at a dip of approximately 10 degrees). Should your configuration be better suited on your mystery planet (steeper dip), and should there be a potential for larger earthquakes than on earth (say &lt;span class=&quot;math-container&quot;&gt;$M_w9.5+$&lt;/span&gt;), only then would there be a  potential for a sizable tsunami with an amplitude at least as large as the sea floor displacement and potentially larger should the bathymetric change. Certainly a &lt;span class=&quot;math-container&quot;&gt;$M_w10+$&lt;/span&gt; would generate a lot (10s of meters) of seafloor displacement, but then, of course, the wavelength would be much bigger than the amplitude.&lt;/p&gt;&#xA;" OwnerUserId="6245" LastEditorUserId="6245" LastEditDate="2022-11-18T19:07:09.207" LastActivityDate="2022-11-18T19:07:09.207" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24531" PostTypeId="1" AcceptedAnswerId="24532" CreationDate="2022-11-18T14:18:26.270" Score="10" ViewCount="141" Body="&lt;p&gt;Last night it dropped to around 25°F here in Wildwood, GA.  I noticed what looked like patches of cotton on the ground that were not there the day before.  At closer look they are patches of frost/ice.  Some, like the image below, appear as if they were spun on a machine.&lt;/p&gt;&#xA;&lt;p&gt;How do these patterns form?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EiGJC.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EiGJC.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Below is another one (photo taken 11-20-2022).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/se3On.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/se3On.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27996" LastEditorUserId="27996" LastEditDate="2022-11-20T18:34:59.870" LastActivityDate="2022-11-20T18:34:59.870" Title="Formation of ice shape" Tags="|ice|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24532" PostTypeId="2" ParentId="24531" CreationDate="2022-11-18T22:48:42.923" Score="10" Body="&lt;p&gt;What you are looking at is called &lt;a href=&quot;https://en.wikipedia.org/wiki/Hair_ice&quot; rel=&quot;noreferrer&quot;&gt;hair ice&lt;/a&gt;.  The Wikipedia article seems a little unclear on the cause, but it seems associated with dead plant material, and the presence of certain fungi.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Hair ice forms on moist, rotting wood from broadleaf trees when&#xA;temperatures are slightly under 0 °C (32 °F) and the air is humid.[1]&#xA;The hairs appear to root at the mouth of wood rays (never on the&#xA;bark), and their thickness is similar to the diameter of the wood ray&#xA;channels.[1] A piece of wood that produces hair ice once may continue&#xA;to produce it over several years.[1]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;More information provided in comments by @trond hansen can be found in another article on Hair Ice at the &lt;a href=&quot;https://www.metoffice.gov.uk/weather/learn-about/weather/types-of-weather/frost-and-ice/hair-ice&quot; rel=&quot;noreferrer&quot;&gt;UKs' Met Office&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6057" LastEditorUserId="6057" LastEditDate="2022-11-19T22:29:21.330" LastActivityDate="2022-11-19T22:29:21.330" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24533" PostTypeId="1" AcceptedAnswerId="24534" CreationDate="2022-11-18T23:14:20.290" Score="5" ViewCount="373" Body="&lt;p&gt;Are the images of city lighting portrayed on these shots from the GOES-East CONUS satellite based on real-time imagery?&lt;/p&gt;&#xA;&lt;p&gt;This time-series was taken as the line of nightfall swept from east to west across the screen.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/w8kyK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/w8kyK.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ckWUx.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ckWUx.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AzT3M.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AzT3M.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rep6i.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rep6i.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Note how the cities around the southern tip of Lake Michigan in particular appear to be initially covered by clouds, then come into view as lighted areas in the darkness, then disappear again -- yet it seems unlikely that the cloud cover has actually ever vanished during this interval.&lt;/p&gt;&#xA;&lt;p&gt;I've also often noticed that cities in my immediate vicinity show up as lighted areas on the GOES-east CONUS satellite shots slightly &lt;em&gt;before&lt;/em&gt; a significant portion of the streetlights etc have actually turned on.&lt;/p&gt;&#xA;&lt;p&gt;(&lt;a href=&quot;https://www.star.nesdis.noaa.gov/GOES/conus_band.php?sat=G16&amp;band=GEOCOLOR&amp;length=24&quot; rel=&quot;nofollow noreferrer&quot;&gt;link to current photos from this satellite&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="24924" LastEditorUserId="543" LastEditDate="2022-11-19T02:12:41.150" LastActivityDate="2022-11-19T02:12:41.150" Title="Are the images of city lights from GOES-East GeoColor based on real-time imagery?" Tags="|weather-satellites|satellite-oddities|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24534" PostTypeId="2" ParentId="24533" CreationDate="2022-11-19T02:08:25.933" Score="6" Body="&lt;p&gt;No, it is not real-time imagery of city lights.  As per the GOES Geo-Color Description (which should be at the &lt;a href=&quot;https://www.star.nesdis.noaa.gov/goes/sector_band.php?sat=G16&amp;amp;sector=ne&amp;amp;band=GEOCOLOR&amp;amp;length=24&quot; rel=&quot;noreferrer&quot;&gt;bottom of the page you are&lt;/a&gt; on):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;GeoColor is a multispectral product composed of True Color (using a simulated green component) during daytime, and an Infrared product that uses bands 7 and 13 at night. During the day, the imagery looks approximately as it would when viewed with human eyes from space. At night, the blue colors represent liquid water clouds such as fog and stratus, while gray to white indicate higher ice clouds, and the city lights come from a static database derived from the VIIRS Day Night Band.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;NOTE: Lighted areas shown in nighttime images are not real-time depictions of city lights. The layer is derived from a compilation of JPSS VIIRS Day Night Band images and is included for orientation purposes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;For more details, see the &lt;a href=&quot;https://www.star.nesdis.noaa.gov/goes/documents/QuickGuide_CIRA_Geocolor_20171019.pdf&quot; rel=&quot;noreferrer&quot;&gt;CIRA GeoColor Product Quick Guide&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="543" LastActivityDate="2022-11-19T02:08:25.933" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24536" PostTypeId="2" ParentId="24421" CreationDate="2022-11-19T09:46:32.310" Score="0" Body="&lt;p&gt;10,000 Years ago , what's now Britain was at mercy of ice age , rendered much vegetation gone. Post ice warming, Plants from mainland migrated to recolonize area. Before human agricultural upheaval. UK was full temperate oak forests, pine, Birch woodlands, heaths and marshes along shores and even some temperate rainforests near its high precipice close to the coast. Holocene warming plant forest diversity was considerably higher.&lt;/p&gt;&#xA;" OwnerUserId="21028" LastActivityDate="2022-11-19T09:46:32.310" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24538" PostTypeId="2" ParentId="24525" CreationDate="2022-11-20T09:06:00.647" Score="1" Body="&lt;p&gt;As I stated in my comment &amp;quot;Whatever salt is in the UK has got nothing to do with the amount of precipitation it receives&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Now to unpick what's in your question.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Rising Damp&lt;/strong&gt; - results from ground water from a high water table rising up  through the pores in brick, mortar and masonry in walls via capillary action.  Dissolved salts in the ground water moves with the water into the bricks and masonry and are deposited when the water evaporates.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Salt sits at the bottom of oceans&lt;/strong&gt; - No it doesn't. There is salt in every part of the ocean. The more correct statement would be that the density of salt increases with depth of the oceans. Per unit volume of sea water, there is more salt dissolved in sea water at depth than at the surface.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;World movement of water causing rainfall is dictated by magnetic waves of the moon on the sea&lt;/strong&gt; - What magnetic waves on the Moon? The &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnetic_field_of_the_Moon&quot; rel=&quot;nofollow noreferrer&quot;&gt;magnetic field on the Moon&lt;/a&gt; is very weak compared to that of the Earth. Because the Earth has a rotating solid inner core, within a liquid hot outer core the Earth has a dynamo magnetic field which protects the planet from solar and cosmic radiation and enables humans and certain animals to navigate the planet via compasses or other magnetic detection devices.&lt;/p&gt;&#xA;&lt;p&gt;What magnetism occurs on the Moon is very weak and is localized to the lunar crust. What you might be confusing is the effect the Moon's &lt;strong&gt;gravity&lt;/strong&gt; has on Earth and its oceans. This is what causes the maritime tides on Earth.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Salt trapping moisture on land, with moisture eventually evaporating from the salt leading to humid air above the land which results in rain&lt;/strong&gt; - This is not peculiar to salt; soil does the same thing. &lt;a href=&quot;https://www.thoughtco.com/forest-transpiration-water-cycle-4117845&quot; rel=&quot;nofollow noreferrer&quot;&gt;Forests transpire&lt;/a&gt; leading to localized rainfall - recirculating the water within a region.&lt;/p&gt;&#xA;&lt;p&gt;Salt deposits on land do not draw in rain clouds. Neither do they force or entice the clouds to dump rain on any such deposits.&lt;/p&gt;&#xA;&lt;p&gt;You were closer to the truth in the title to your question. The reason why the UK receives as much rain as it does is because it is a small island in a very active ocean. The &lt;a href=&quot;http://news.bbc.co.uk/2/hi/uk_news/england/derbyshire/3090539.stm&quot; rel=&quot;nofollow noreferrer&quot;&gt;furthest point from the coast&lt;/a&gt; is &amp;quot;Church Flatts Farm in Derbyshire, which is which is 70 miles (113 km) from the nearest coast, the mean low water line at Fosdyke Wash, on the edge of The Wash, south of Boston, in Lincolnshire&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Because of this, the air in the UK is humid and it just takes a cold front to cause the atmospheric moisture to precipitate.&lt;/p&gt;&#xA;&lt;p&gt;As for Wales being wetter than Sussex, Wales has mountains that act a barriers to clouds moving from the west. As the clouds rise to go over the mountains they drop their moisture as rain. To the east of the mountains there will most likely be a rain shadow region which receives much less rainfall. Sussex is further to the east and has no coastal or western mountains. Any rain cloud can more easily blow over Sussex and thus Sussex receives less rain.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="21672" LastEditDate="2022-11-21T09:35:01.367" LastActivityDate="2022-11-21T09:35:01.367" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24541" PostTypeId="1" CreationDate="2022-11-21T18:34:16.900" Score="3" ViewCount="205" Body="&lt;p&gt;I'm completely lost...In an elementary course on meteorology, we recently learned how to explain the greenhouse effect in terms of a simple single-layer atmosphere model.&lt;/p&gt;&#xA;&lt;p&gt;Based on the image below temperatures &lt;span class=&quot;math-container&quot;&gt;$T_s$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$T_a$&lt;/span&gt; are derived by a fairly simple calculation:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gkAhH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gkAhH.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$T_s = T_e \left(\frac{2}{2-\epsilon}\right)^{1/4} \tag{1}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$T_a = T_e \left(\frac{1}{2}\right)^{1/4} \tag{2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$T_s$&lt;/span&gt; denotes the ideal earth temperature without atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;Although quite logical I feel a slight kind of inconsistency in it: We calculate the temperature of the atmosphere to be lower than that from earth by a fixed factor 0,84. But nothing is said about the height of this atmospheric layer. How can this be, because the temperature in an atmosphere's layer is (at least to some degree) given by an adiabatic temperature gradient and, therefore, there is no additional freedom in temperature in a given height when temperature on ground is given.&lt;/p&gt;&#xA;&lt;p&gt;My conclusion would be, that under equilibrium conditions the part of the atmosphere which contributes most to outgoing radiation (&amp;quot;the single layer&amp;quot;) corresponds to a height, where temperature matches equation (2). OK. But on the other hand, the portion of atmosphere, which radiates directly into open space must be within a layer of optical thickness of about &lt;span class=&quot;math-container&quot;&gt;$\tau \approx 1$&lt;/span&gt; &lt;em&gt;measured from TOA down&lt;/em&gt;, because layers below should be opaque from the outside view. So there is also no freedom in the height of the emitting layer, because it is solely given by optical thickness and the more greenhouse gases there are, the higher this &amp;quot;last emitting&amp;quot; layer must be.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, to make my confusion complete, when viewed from earth's surface, radiation received by surface must be from a layer within about optical thickness &lt;span class=&quot;math-container&quot;&gt;$\tau \approx 1$&lt;/span&gt; &lt;em&gt;measured from surface level up&lt;/em&gt;. But this height must be significantly lower as compared to the height of the layer which radiates into space - otherwise atmosphere would be transparent for IR. So how can we speak of a &amp;quot;single layer&amp;quot; and why does it give correct numbers?&lt;/p&gt;&#xA;&lt;p&gt;So I don't get along with this description at all, although I would like it for its simplicity, not least because it gives a result consistent with data. Where is my misconception? I've been pondering this for a good month now and nobody can tell me what I'm doing wrong. Up to now, the field of meteorology appears a bit alchemistic for me.&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2022-11-21T18:45:58.440" LastActivityDate="2022-11-21T18:45:58.440" Title="How can a single layer atmospheric model for the greenhouse effect be consistent with adiabatic temperature gradient and optical depth considerations?" Tags="|meteorology|climate-change|greenhouse-gases|atmospheric-radiation|radiation-balance|" AnswerCount="0" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="24543" PostTypeId="2" ParentId="24495" CreationDate="2022-11-22T01:07:20.477" Score="3" Body="&lt;p&gt;Your confusion, I think, comes from a subtlety, and I think I can only answer this from the perspective of an astrophysicist. We don't think in terms of &amp;quot;forcings&amp;quot;, the vocabulary is still alien to me (I have yet to see a sensible, formal defition of it). But I will answer in terms of a certainly related concept.&lt;/p&gt;&#xA;&lt;p&gt;In the optically thick part of an atmosphere (i.e. the one that potentially features a greenhouse effect), we know from &lt;a href=&quot;https://ui.adsabs.harvard.edu/abs/2010A%26A...520A..27G/abstract&quot; rel=&quot;nofollow noreferrer&quot;&gt;analytic solutions&lt;/a&gt; that the Temperature &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; as function of optical depth &lt;span class=&quot;math-container&quot;&gt;$\tau$&lt;/span&gt; is approximately &lt;span class=&quot;math-container&quot;&gt;$T^4=T^4_0(\frac{2}{3} + \tau)$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$T_0$&lt;/span&gt; is a measure of the energy content of the optically thin radiation field.&lt;/p&gt;&#xA;&lt;p&gt;The total optical depth &lt;span class=&quot;math-container&quot;&gt;$\tau$&lt;/span&gt;, itself is simply computed as a sum of all opacity carrier contributing species &lt;span class=&quot;math-container&quot;&gt;$s$&lt;/span&gt;, with number densities &lt;span class=&quot;math-container&quot;&gt;$n_s$&lt;/span&gt;, opacity function &lt;span class=&quot;math-container&quot;&gt;$\kappa_s$&lt;/span&gt;, and optical ray path &lt;span class=&quot;math-container&quot;&gt;$ds$&lt;/span&gt; as &lt;span class=&quot;math-container&quot;&gt;$$\tau = \sum_s \int ds \, n_s \, \kappa_s. $$&lt;/span&gt;&#xA;This already answers the part of your question about the partial pressure dependency: &lt;span class=&quot;math-container&quot;&gt;$\tau\propto n_s$&lt;/span&gt;, no matter how the opacity is generated (I am using pressure and number density at constant temperature interchangeably, but to first order it is &lt;span class=&quot;math-container&quot;&gt;$n_s$&lt;/span&gt; and not &lt;span class=&quot;math-container&quot;&gt;$p_s$&lt;/span&gt; determining &lt;span class=&quot;math-container&quot;&gt;$\tau$&lt;/span&gt;).&lt;br /&gt;&#xA;Now collision-induced absorption, which gives rise to the broad Lorentzian line wings, which grow logarithmically at large optical depth, is dependent on all available collision partners, hence this is where the total pressure comes into play, via &lt;span class=&quot;math-container&quot;&gt;$\kappa_{CO2} = \kappa_{CO2}(\sum_s n_s)$&lt;/span&gt;. In the last sum, the &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; contribution would be negligible, but &lt;span class=&quot;math-container&quot;&gt;$\kappa_{CO2}$&lt;/span&gt; still grows logarithmically.&lt;/p&gt;&#xA;&lt;p&gt;So in my understanding we'd rather have something along the lines of &lt;span class=&quot;math-container&quot;&gt;$\tau \propto n_s \times log(f(\sum_s n_s))$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;I would still like to better understand how the 'forcing' comes about from those quantities, but it does give you an answer as to why the temperature to which the system wants to get to (the above &lt;span class=&quot;math-container&quot;&gt;$T^4$&lt;/span&gt;) has the dependencies that you are confused about.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2022-11-22T01:07:20.477" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24544" PostTypeId="2" ParentId="24435" CreationDate="2022-11-22T01:30:10.553" Score="3" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;which other areas of the planet might contain rich and unique fossil resources from the Mesozoic and which are still unexplored or underexplored.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;During the  Cretaceous  period &lt;a href=&quot;https://www.bbcearth.com/news/when-dinosaurs-roamed-antarctica&quot; rel=&quot;nofollow noreferrer&quot;&gt;Antarctica was ice-free and had temperate temperatures and forests covered Antarctica,&lt;/a&gt; Dinosaurs roamed Antarctica around the middle-end of the Mesozoic. I wouldn't be surprised if there were many Dinosaur fossils found in Antarctica because of the abundunce of forests and Dinosaurs 145 to 66 Million years ago, It would make sense if most of these fossils were found someplace else because ice sheets move and can pick up and carry Dinosaur fossils with them and then melt and deposit them someplace else.&lt;/p&gt;&#xA;" OwnerUserId="21926" LastActivityDate="2022-11-22T01:30:10.553" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24545" PostTypeId="2" ParentId="16706" CreationDate="2022-11-22T10:30:18.853" Score="5" Body="&lt;p&gt;During my PhD, I listed many dacite and rhyolite flows, but also included a few andesite flows for comparison. Here are a few interesting examples, first of andesite flows that have been observed while active (for which we have velocity measurements), then of past, frozen flows (for which we have the length only).&lt;/p&gt;&#xA;&lt;h3&gt;Active flows&lt;/h3&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Lonquimay volcano, 1988–1990&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;0.23 km&lt;sup&gt;3&lt;/sup&gt; of lava, emplaced over 13 months, reaching a distance of 10.2 km from the vent, according to &lt;a href=&quot;https://doi.org/10.1017/S0016756800008426&quot; rel=&quot;noreferrer&quot;&gt;Naranjo et al. (1992)&lt;/a&gt;. The article contains nice data of lava flow advance (Table 3), allowing for calculating velocities. The velocity ranged from ~&lt;span class=&quot;math-container&quot;&gt;$10^{-2}$&lt;/span&gt; m/s at the beginning of the eruption to ~&lt;span class=&quot;math-container&quot;&gt;$10^{-4}$&lt;/span&gt; m/s at the end, and the slope from 1 to 6°. You can already see that velocity does not depend on slope, I will come back to this later on.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Kizimen volcano, 2011–2012&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;0.30 km&lt;sup&gt;3&lt;/sup&gt; of lava, emplaced over ~17 months, reaching a distance of 3.5 km from the vent, according to &lt;a href=&quot;https://doi.org/10.1007/s00445-018-1199-z&quot; rel=&quot;noreferrer&quot;&gt;Auer et al. (2018)&lt;/a&gt;. Their Table 1 shows that the slope was much steeper than at Lonquimay (10&lt;span class=&quot;math-container&quot;&gt;$-$&lt;/span&gt;26°), but the flow is not even half as long, with a similar magma volume. Velocity was in the order of ~&lt;span class=&quot;math-container&quot;&gt;$10^{-4}$&lt;/span&gt; m/s (Table 1). Note that this flow is borderline andesitic, involving magma mingling between two components:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Dark and light bands show a range of whole rock compositions between 62 wt% SiO&lt;sub&gt;2&lt;/sub&gt; for the dark silica-rich andesitic endmember and 65 wt% SiO&lt;sub&gt;2&lt;/sub&gt; for the light dacitic endmember&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Sinabung volcano, 2014–2015&lt;/strong&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;0.10 km&lt;sup&gt;3&lt;/sup&gt; of lava, emplaced over a year, reaching a distance of ~3 km from the vent. There is a &lt;a href=&quot;https://www.sciencedirect.com/journal/journal-of-volcanology-and-geothermal-research/vol/382/suppl/C&quot; rel=&quot;noreferrer&quot;&gt;whole issue of JVGR&lt;/a&gt; on this eruption. This flow reached the same length as the Kizimen one, despite being less voluminous (hence it was &amp;quot;thinner&amp;quot;, with a max thickness of ~100 m, versus &amp;gt; 200 m at Kizimen). The slope was variable: 33° for the first 1 km, 15° for 1–2 km, and 9° for the last 0.5 km. The velocity was ~&lt;span class=&quot;math-container&quot;&gt;$10^{-3}$&lt;/span&gt; m/s at the beginning of the eruption, and ~&lt;span class=&quot;math-container&quot;&gt;$10^{-5}$&lt;/span&gt; m/s at the end, but again &lt;em&gt;this is not due to the change in slope&lt;/em&gt; (see below).&lt;/p&gt;&#xA;&lt;h3&gt;Frozen flows&lt;/h3&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1130/2018.2538(05)&quot; rel=&quot;noreferrer&quot;&gt;Gusey et al. (2018)&lt;/a&gt; describe two andesite lava flows that are among the longest known, with lengths of 52 and 74 km. This gives you an idea of the upper bound. Of course you need more volume to reach such lengths: minimal volume estimates are 2.5 and 6.6 km&lt;sup&gt;3&lt;/sup&gt;, respectively.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1007/s00445-016-1020-9&quot; rel=&quot;noreferrer&quot;&gt;Chevrel et al. (2016)&lt;/a&gt; describe several voluminous andesite flows at El Metate volcano. The largest, named F6, is 15 km long, with a volume of 2.2 km&lt;sup&gt;3&lt;/sup&gt;. This paper is also a nice example of how you can infer dynamics parameters of frozen flows. For F6, they inferred a velocity in the order of ~&lt;span class=&quot;math-container&quot;&gt;$10^{-4}$&lt;/span&gt; m/s.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Yet another example is the 6.5 km long Oturere andesite flow, at Tongariro volcano, where &lt;a href=&quot;https://doi.org/10.1080/00288306.2002.9514980&quot; rel=&quot;noreferrer&quot;&gt;Stevens (2002)&lt;/a&gt; calculated a volume of 0.37 km&lt;sup&gt;3&lt;/sup&gt;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;h3&gt;Factors controlling lava flow length&lt;/h3&gt;&#xA;&lt;p&gt;As you can see from these examples, andesite effusive eruptions with similar magma volumes can yield lava flows of different lengths. But the main factor controlling lava flow length is not the slope&lt;span class=&quot;math-container&quot;&gt;$-$&lt;/span&gt;it would be if lava was a Newtonian fluid, which it isn't. &lt;a href=&quot;https://www.jstor.org/stable/74335&quot; rel=&quot;noreferrer&quot;&gt;Walker (1973)&lt;/a&gt; &lt;em&gt;Lengths of lava flows&lt;/em&gt; summarizes it well:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The principal factor influencing the length of a lava flow is the rate&#xA;of effusion. With a high rate the lava flows rapidly from the source&#xA;and tends to form an extensive and far-reaching flow which is simple&#xA;in character (i.e. made of a single flow unit). With a low rate the&#xA;lava tends to pile up layer upon layer to form a local accumulation of&#xA;limited lateral extent near the source, and this accumulation strongly&#xA;compound in character (i.e. divisible into flow units).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You can see the correlation between effusion rate and flow length on his Figure 4. Now, the reality is a bit more complex, and much work have been done since, but his assertion still stands true. At Lonquimay and Sinabung for instance, you'll see in the references that changes in effusion rate has been linked to changes in lava flow velocity (and, ultimately, to final length).&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2022-11-22T10:30:18.853" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24547" PostTypeId="2" ParentId="24435" CreationDate="2022-11-23T18:13:25.203" Score="-2" Body="&lt;p&gt;More areas than can be listed here.&lt;/p&gt;&#xA;&lt;p&gt;fossils are almost everywhere, almost everyplace with sedimentary rocks. So wherever you have Mesozoic rock you may find fossils.&lt;/p&gt;&#xA;&lt;p&gt;It is exposed fossils that are hard to find.&lt;/p&gt;&#xA;&lt;p&gt;Kansas for instance likely has massive Mesozoic fossil deposits, but it is under meters of soil. the planet is covered in places which likely have Mesozoic fossils but lack exposures. this is why road cuts and large scale excavations so often expose fossils.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2022-11-24T06:12:09.540" LastActivityDate="2022-11-24T06:12:09.540" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24548" PostTypeId="1" CreationDate="2022-11-23T22:23:54.867" Score="2" ViewCount="46" Body="&lt;p&gt;Is there a word for the phenomenon of water seeming to rush out to meet an oncoming wave? Perhaps it's more of a physics terminology question?&lt;/p&gt;&#xA;" OwnerUserId="28027" LastActivityDate="2022-11-23T22:23:54.867" Title="Water rushing out to meet wave term" Tags="|waves|terminology|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24549" PostTypeId="2" ParentId="23089" CreationDate="2022-11-24T16:48:52.750" Score="0" Body="&lt;p&gt;You might try a latitudinally-resolved climate model.  These were invented in 1969 to see how global warming or cooling moved the boundaries of the polar caps.  One result is that a slight decrease in the Solar constant glaciates the Earth; that's because the models don't include the carbonate-silicate cycle which stabilizes Earth's temperature in the long run.  But for examining small changes it might be okay.&lt;/p&gt;&#xA;&lt;p&gt;The basic equation is one of power balance (usually incorrectly called &amp;quot;energy balance&amp;quot;):&lt;/p&gt;&#xA;&lt;p&gt;Qi (1 - Ai) = A + B Ti + C(Ti - T)&lt;/p&gt;&#xA;&lt;p&gt;Here Qi is the insolation, averaged over the year, in a given latitude band, band i--you need a lot of spherical astronomy and trig to figure this out, but some articles (e.g. Warren and Schneider 1979 or Chylek and Coakley 1975) have precalculated tables you can use.  Ai is the albedo in that band--you can set this to flip from a high value (bright, icy) to a low value (dark, uncovered) when temperature goes over a critical value, like 273 K.  The whole left-hand side of the equation, then, is the solar power absorbed in that climate band.&lt;/p&gt;&#xA;&lt;p&gt;A + B Ti is the infrared power emitted by that band to space.  A and B are constants (A is not the albedo Ai), and Ti is the band's temperature--normally you start out with an isothermal Earth and then iterate until the simulation stabilizes.  Values for A and B vary somewhat in the literature, but in a recent paper I used A = 214.5 W m^-2 and B = 1.57 W m^-2 K^-1.&lt;/p&gt;&#xA;&lt;p&gt;The last term is the energy moved from one band to another, in a very simple (read &amp;quot;crude&amp;quot;) &amp;quot;diffusion&amp;quot; model.  C is a constant, Ti is and temperature, and T is the average temperature of the whole globe (I'll tell you how to calculate that in a minute).  Again, values for C vary.  Recently I used C = 3.74 W m^-2 K^-1.&lt;/p&gt;&#xA;&lt;p&gt;You can find the mean global albedo or temperature or what-have-you by multiplying the zonal values by the zonal area fraction and adding up all the figures.  You find the fraction of a hemisphere's area by subtracting the sine of the more equatorial boundary from the sine of the more polar boundary.  For instance, the area of a hemisphere between 30 and 40 degrees is sin(40) - sin(30) = 0.1428.&lt;/p&gt;&#xA;&lt;p&gt;P. Chýlek, J.A. Coakley, Jr.  J. Atmos. Sci. 32, 675-679 (1975).&lt;/p&gt;&#xA;&lt;p&gt;S.G. Warren, S.H. Schneider.  J. Atmos. Sci. 36, 1377-1391 (1979).&lt;/p&gt;&#xA;" OwnerUserId="12453" LastActivityDate="2022-11-24T16:48:52.750" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24550" PostTypeId="2" ParentId="9589" CreationDate="2022-11-24T18:56:10.960" Score="1" Body="&lt;p&gt;It is chemical weathering. It is caused by reaction to sunlight or caustic pH in soil that starts breaking down the non silica impurities in the agate. Heat from a natural forest fire can also cause this. You will often see many fractures from heat altering.&lt;/p&gt;&#xA;" OwnerUserId="28031" LastEditorUserId="2470" LastEditDate="2023-03-06T10:20:58.447" LastActivityDate="2023-03-06T10:20:58.447" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24551" PostTypeId="2" ParentId="4874" CreationDate="2022-11-24T19:58:13.077" Score="0" Body="&lt;p&gt;Start with the Earth's radiative equilibrium temperature T&lt;sub&gt;e&lt;/sub&gt;:&lt;/p&gt;&#xA;&lt;p&gt;S (1 - A) [T&lt;sub&gt;e&lt;/sub&gt;] = 4 &lt;sub&gt;e&lt;/sub&gt;&lt;sup&gt;2&lt;/sup&gt;] e s Te&lt;sup&gt;4&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;where S is the Solar constant, A the planetary albedo, pi the circle constant (3.14159...), R&lt;sub&gt;e&lt;/sub&gt; the Earth's radius, e emissivity, s the Stefan-Boltzmann constant, and T&lt;sub&gt;e&lt;/sub&gt; the temperature we're looking for.  Solving for T&lt;sub&gt;e&lt;/sub&gt;, [T&lt;sub&gt;e&lt;/sub&gt;] cancels, and S 1361.5 W m&lt;sup&gt;-2&lt;/sup&gt;, A 0.294, e 1 (always taken as 1 at the top of a planet's atmosphere) gives you Te = 255 K.&lt;/p&gt;&#xA;&lt;p&gt;This is below freezing, since water freezes at 273 K, so obviously something else keeps the surface hotter--the greenhouse effect.  Actual surface temperature Ts is now about 288 K.  A simple (too simple) model is the Milne-Eddington approximation:&lt;/p&gt;&#xA;&lt;p&gt;T&lt;sub&gt;s&lt;/sub&gt; = T&lt;sub&gt;e&lt;/sub&gt;(1 + 0.75 τ)&lt;sup&gt;0.25&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;where tau is the atmosphere's long wave optical depth.  The present value of this is about 1.84, which gives you T&lt;sub&gt;s&lt;/sub&gt; = 317 K, too high.  This is because this approximation fails to account for surface cooling by convection and conduction.&lt;/p&gt;&#xA;&lt;p&gt;The more greenhouse gases you have in the atmosphere, the higher τ gets, and the higher T&lt;sub&gt;s&lt;/sub&gt; goes.  Many &amp;quot;semigray&amp;quot; approximations model partial τ (&amp;quot;partial&amp;quot; meaning for each gas) as a function of the gas's partial pressure, usually raised to some power.  Add up the partials to get tau.  It may help to know that at present, water vapor accounts for about 50% of τ, clouds 25%, carbon dioxide 20%, and minor gases (CH&lt;sub&gt;4&lt;/sub&gt;, O&lt;sub&gt;3&lt;/sub&gt;, N&lt;sub&gt;2&lt;/sub&gt;O, etc.) 5%.&lt;/p&gt;&#xA;&lt;p&gt;I hope this is enough to get you started.&lt;/p&gt;&#xA;" OwnerUserId="12453" LastEditorUserId="2470" LastEditDate="2022-11-25T03:15:26.060" LastActivityDate="2022-11-25T03:15:26.060" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24553" PostTypeId="1" CreationDate="2022-11-25T09:21:59.097" Score="4" ViewCount="915" Body="&lt;p&gt;I'm trying to calculate the saturated moist adiabatic lapse rate with the following formula:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$L_m = \frac{y_d}{1+\frac{L_v}{c_p}\frac{d_q(s)}{dT}}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;with:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$y_d = 9.8 (K\ km^{-1})\\\\$&lt;/span&gt;,&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$L_v = 2.5*10^6 (J\ kg^{-1})\\\\$&lt;/span&gt;,&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$c_p = 1004 (J\ kg^{-1} K^{-1})\\\\$&lt;/span&gt;,&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; = temperature &lt;span class=&quot;math-container&quot;&gt;$(K)\\\\$&lt;/span&gt;,&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$q(s)$&lt;/span&gt; = saturation specific humidity &lt;span class=&quot;math-container&quot;&gt;$(kg/kg)\\\\$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Imagine air at a pressure level of 760 hPa that has a temperature of 4 degrees Celsius. If I fill in the formula:&lt;/p&gt;&#xA;&lt;p&gt;First calculate the saturation specific humidity for 2 temperatures:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$qs_1$&lt;/span&gt; for &lt;span class=&quot;math-container&quot;&gt;$T_1$&lt;/span&gt; (3°C) = 0.622*((6.11*exp(19.85 - 5423/(273.15+3))*100))/(76000) * 1000&#xA;= 6.18 g/kg = 0.006180 kg/kg&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$qs_2$&lt;/span&gt; for &lt;span class=&quot;math-container&quot;&gt;$T_2$&lt;/span&gt; (5°C) = 0.622*((6.11*exp(19.85 - 5423/(273.15+5))*100))/(76000) * 1000&#xA;= 7.12 g/kg = 0.007120 kg/kg&lt;/p&gt;&#xA;&lt;p&gt;Fill in the formula:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$L_m = \frac{0.0098}{1+\frac{2.5*10^6}{1004}\frac{0.007120-0.006180}{5-3}} = 8.34480 \ K\ km^{-1}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;This seems rather high. Am I doing something wrong?&lt;/p&gt;&#xA;" OwnerUserId="28035" LastEditorUserId="28035" LastEditDate="2022-11-25T14:54:07.117" LastActivityDate="2022-11-25T14:54:07.117" Title="How to calculate the moist adiabatic lapse rate?" Tags="|meteorology|atmosphere|thermodynamics|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24554" PostTypeId="1" AcceptedAnswerId="24561" CreationDate="2022-11-25T16:04:07.807" Score="4" ViewCount="119" Body="&lt;p&gt;I have been fascinated with the wind animation that I have seen on sites like Zoom earth. What is the &amp;quot;thickness&amp;quot; of the air stream that the animation represents. How far from the surface is this information accurate?&lt;/p&gt;&#xA;" OwnerUserId="28036" LastActivityDate="2022-12-24T09:10:58.637" Title="Wind animation from satellite" Tags="|wind|weather-satellites|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24555" PostTypeId="1" CreationDate="2022-11-25T20:42:47.763" Score="4" ViewCount="154" Body="&lt;p&gt;According to Takahashi et al. (1993), pCO2 (partial pressure of CO2) in the surface ocean changes due to 4 surface variables: temperature, salinity, total carbon (dissolved inorganic carbon, DIC) and total alkalinity (ALK). The latter relationship, in specific, is inversely proportional. Increasing alkalinity decreases surface pCO2 and vice versa. Why?&lt;/p&gt;&#xA;&lt;p&gt;If anything, I would expect that decreasing alkalinity would decrease pCO2. I would believe this because removing carbonate and bicarbonate ions (which compose alkalinity), at constant pH, would force some CO2 to dissolve into these ions again to maintain the relative distribution at a constant pH, thus decreasing pCO2. This relative balance is illustrated for example in the figure below from chapter 8 in Sarmiento (2013). Why is the opposite true?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DGTMU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DGTMU.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Taro Takahashi; Jon Olafsson; John G. Goddard; David W. Chipman; S. C. Sutherland (1993). Seasonal variation of CO&lt;sub&gt;2&lt;/sub&gt; and nutrients in the high-latitude surface oceans: A comparative study. , 7(4), 843–0. doi:10.1029/93gb02263&lt;/p&gt;&#xA;&lt;p&gt;Sarmiento, Jorge L. &amp;quot;Ocean biogeochemical dynamics.&amp;quot; Ocean Biogeochemical Dynamics. Princeton University Press, 2013.&lt;/p&gt;&#xA;" OwnerUserId="28038" LastEditorUserId="28038" LastEditDate="2022-11-25T20:43:43.787" LastActivityDate="2023-12-22T16:00:25.080" Title="Why does decreasing surface alkalinity increase surface pCO2?" Tags="|oceanography|geochemistry|carbon-cycle|biogeochemistry|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24556" PostTypeId="1" CreationDate="2022-11-25T21:00:28.833" Score="1" ViewCount="161" Body="&lt;p&gt;I am beginning my research on climate change and am not familiar with all of the problems that can occur. At the same time, I know there are potential solutions to react to climate change.&lt;/p&gt;&#xA;&lt;p&gt;For example, I know electric vehicles is a possible solution but at the same time there are downsides because it is expensive and other environmental negatives could result from this.&lt;/p&gt;&#xA;&lt;p&gt;For example, fracking is an inexpensive way as an alternative to coal. At the same time though, it could cause air and water pollution along with risk of earthquakes.&lt;/p&gt;&#xA;&lt;p&gt;Is there a list somewhere that has all of the potential solutions with pros and cons?&lt;/p&gt;&#xA;" OwnerUserId="28039" LastActivityDate="2022-11-25T21:00:28.833" Title="Climate Change Solutions - Pros and Cons" Tags="|climate-change|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24558" PostTypeId="2" ParentId="16109" CreationDate="2022-11-26T04:55:18.710" Score="-1" Body="&lt;p&gt;As an alternative, we commonly use a relationship of pressure or hgt between the values at the surface and a given level. This &lt;a href=&quot;https://gradsaddict.blogspot.com/2013/05/tutorial-vertical-cross-section-with.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt; might be helpful.&lt;/p&gt;&#xA;" OwnerUserId="28040" LastActivityDate="2022-11-26T04:55:18.710" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24561" PostTypeId="2" ParentId="24554" CreationDate="2022-11-26T19:30:10.553" Score="4" Body="&lt;p&gt;The data that you are seeing is the wind speed the models predict at 10m above the 'model surface'. 10m is the standardised height at which wind is measured, as defined by the World Meteorological Organization. There is no 'thickness' to the data shown. On other websites that give you more direct access to the data, you can look at wind speed predictions for a number of different 'pressure surfaces' as well as the 10m-above-the-surface surface.&lt;/p&gt;&#xA;&lt;p&gt;On Zoom Earth, you can see winds speeds are much higher over sea than land. This is a good indication of low altitude winds, which you can look for on other websites too if you are uncertain what wind data are shown. This is due to the friction of the land surface. As you increase in height this effects drops off quickly, except perhaps in mountainous areas.&lt;/p&gt;&#xA;&lt;p&gt;Earlier, I referred to the 'model surface'. Here's an explanation of how that this different to the actual Earth's surface and it's consequences to the modelling: Model resolutions vary but each grid point typically covers somewhere between a 2×2km² to a 30×30km² square. Each grid point is given a single height measurement, which is the average height of the model grid square. This results in a smoothing of the modelled Earth's surface; sharp peaks and valley are missed. This smoothing affects the behaviour of the modelled wind and the height at which it may actually be experienced. Out at sea, the smoothing is not a consideration and there is physically less friction so wind modelling tends to be more accurate.&lt;/p&gt;&#xA;&lt;p&gt;Here is an embarrassingly rough sketch showing this graphically. The data you are looking at is the wind speed the model predicts along the blue line.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oKAQo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oKAQo.png&quot; alt=&quot;Image tries to show how topography is smoothed in a weather model and that the wind shown in Zoom is 10m above this surface.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;A note on models on Zoom Earth:&#xA;Zoom says it uses data from the GFS and ICON models. GFS has a resolution of 27km, so there will be strong smoothing. The various ICON models use 2.2km, 7km, and 13km resolutions. I don't know which ICON model Zoom Earth gets its data from.&lt;/p&gt;&#xA;" OwnerUserId="20542" LastEditorUserId="20542" LastEditDate="2022-12-24T09:10:58.637" LastActivityDate="2022-12-24T09:10:58.637" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24562" PostTypeId="1" CreationDate="2022-11-26T20:55:13.477" Score="2" ViewCount="161" Body="&lt;p&gt;I was told that if I take a shorter shower it will impact the environment positively. That extra water saved could be used for struggling countries or other uses. As a result, I should take a 5min shower instead of a 10min shower.&lt;/p&gt;&#xA;&lt;p&gt;Is there any research done on this topic to prove the impact of this?&lt;/p&gt;&#xA;&lt;p&gt;My counter argument to this is that this cannot be that big of an impact since there are 8 billion people on the planet and 1 person taking a shorter shower will not help solve this issue. And even if we collectively try and do this I cannot see how this makes an impact.&lt;/p&gt;&#xA;&lt;p&gt;Are there alternative solutions at a larger scale that will help with this shower use impact from humans and what is the current impact of shower usage from humans?&lt;/p&gt;&#xA;" OwnerUserId="28039" LastActivityDate="2022-11-27T01:13:11.090" Title="Shorter Showers Effect on Environment" Tags="|climate-change|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24563" PostTypeId="2" ParentId="24562" CreationDate="2022-11-27T01:13:11.090" Score="1" Body="&lt;p&gt;Not all of the 8 billion humans on Earth are able to have at least one shower per day because there isn't enough water for everyone to do so.&lt;/p&gt;&#xA;&lt;p&gt;Local water availability depends on a number of factors: rainfall in the region and adjacent regions and the ability to store the water for periods of low rainfall. Some people may want to raise the matter of ground water stores which can be accessed via wells or water bores. Ultimately, all water sources on land depend on rainfall.&lt;/p&gt;&#xA;&lt;p&gt;In most affluent countries people can take at least one shower per day. In regions with prolonged severe drought, as the southern and western part of the US are experiencing were water storages are very low resulting in some people reconsidering there current water usage, with the aim of reducing such usage.&lt;/p&gt;&#xA;&lt;p&gt;The amount of water a person usages during a shower depends on the flow rate of water through the shower head and the duration of the shower. In some jurisdictions people are encouraged to change their shower heads to low flow heads, which reduce the amount of water they discharge.&lt;/p&gt;&#xA;&lt;p&gt;Different website give different quantities for the amount of water a shower head releases. &lt;a href=&quot;https://showermaestro.com/blog/many-gallons-water-does-shower-use/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Taking one at random&lt;/a&gt;, in the US,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The standard shower head produces about 2.5 gallons per minute (9.5 L/min). That is 25 gallons of water every ten minutes (95 liters every ten minutes).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;If this is typical, a person uses 175 gallons (662.5 L) of water per week for showers. During the course of one year, that amounts to 9125 gallons (34 542 L). In a &lt;a href=&quot;https://www.statista.com/statistics/241695/number-of-us-cities-towns-villages-by-population-size/&quot; rel=&quot;nofollow noreferrer&quot;&gt;city of 100 000 people&lt;/a&gt;, that's 912.5 million gallons (3454 ML) of water per year - a significant amount of water.&lt;/p&gt;&#xA;&lt;p&gt;If everyone took a 5 minute shower, instead of a 10 minute one, the water consumption would be halved which would greatly affect the region's water stores and make a water crisis situation, as currently exists in many parts of the US, a little more tolerable.&lt;/p&gt;&#xA;&lt;p&gt;One person may not make a difference, but the collective action of a large number will. By reducing water consumption you are doing something for your location community, not for others in other countries.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-11-27T01:13:11.090" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24565" PostTypeId="1" CreationDate="2022-11-27T10:03:47.367" Score="2" ViewCount="95" Body="&lt;p&gt;It is known, that due to global warming, the average temperature on Earth over the past 100 years has increased by 1.2 degrees. At the same time, I heard that earlier the temperature of the Earth was 7 degrees higher than the current one.&lt;/p&gt;&#xA;&lt;p&gt;I do not deny the danger of global warming, because I have seen the information that not only the concentration of CO2 is important, but also the rate of its change: with the current rate, the ecosystems do not have enough time to react, and positive feedback can work now (the ocean, heating up, releases water vapor, which is also a greenhouse gas). But I would like to see these points explained in more detail.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.pnas.org/doi/full/10.1073/pnas.1910114117&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.pnas.org/doi/full/10.1073/pnas.1910114117&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here it is written that in the cause of &amp;quot;business-as-usual climate scenario&amp;quot; (this means the worst scenario,  if no mitigating action were taken?), on the territories, where 3.5 billion people are living now, the mean annual temperature (MAT) will be like in Sahara now (and the human life there will be impossible). These territories include half of Africa, half of Arabian Peninsula, most of India, most of Southeast Asia, a part of Australia and a half os South America. How probable is this scenario considered? And what is the scenarion if the states will reduce the CO2 emission as planned now?&lt;/p&gt;&#xA;" OwnerUserId="28047" LastEditorUserId="595" LastEditDate="2022-12-07T10:33:58.900" LastActivityDate="2022-12-07T10:33:58.900" Title="What consequences of the global climate change are expected in the next 50 years?" Tags="|climate-change|temperature|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24567" PostTypeId="2" ParentId="24555" CreationDate="2022-11-27T13:11:31.613" Score="1" Body="&lt;p&gt;The answer is right there on the figure, also known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Bjerrum_plot&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bjerrum plot&lt;/a&gt;. If you decrease alkalinity (i.e. increase pH) you shift the relative proportions of the plot to the right, that is, decreasing H2CO3 (or dissolved CO2) concentrations, and increasing bicarbonate and carbonate ions concentrations. And vice versa. Increasing alkalinity decreases pH, increasing pCO2.&lt;/p&gt;&#xA;" OwnerUserId="8396" LastActivityDate="2022-11-27T13:11:31.613" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="24569" PostTypeId="1" CreationDate="2022-11-28T12:17:36.327" Score="3" ViewCount="94" Body="&lt;p&gt;&lt;a href=&quot;http://vo.imcce.fr/insola/earth/online/earth/online/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;This grapher&lt;/a&gt; states that the Sun energy output in watts/m&lt;sup&gt;2&lt;/sup&gt; has not changed in 2200 years (0.0022 Ma ago until 0 Ma ago) .&lt;/p&gt;&#xA;&lt;p&gt;Why is there an invariance as time approaches glacial minimum?&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th style=&quot;text-align: center;&quot;&gt;Years Ago&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: center;&quot;&gt;Insolation (W/m&lt;sup&gt;2&lt;/sup&gt;)&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;2200&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.052 754&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;2.1&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.052 556&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;2.0&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.052 362&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;1.9&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.052 175&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;1.8&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.051 989&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;1.7&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.051 802&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;1.6&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.051 613&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;1.5&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.051 421&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;1.4&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.051 225&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;1.3&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.051 023&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;1.2&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.050 814&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;1.1&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.050 598&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;1.0&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.050 373&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;0.9&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.050 128&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;0.8&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.049 875&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;0.7&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.049 615&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;0.6&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.049 349&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;0.5&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.049 079&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;0.4&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.048 806&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;0.3&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.048 532&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;0.2&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.048 257&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;0.1&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.047 984&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;0.0&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: center;&quot;&gt;342.047 714&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;" OwnerUserId="3315" LastEditorUserId="2470" LastEditDate="2023-01-04T18:25:13.657" LastActivityDate="2023-01-04T18:25:13.657" Title="Why does this resource give no insolation change since Roman times?" Tags="|climate-change|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24570" PostTypeId="2" ParentId="24524" CreationDate="2022-11-28T18:35:22.570" Score="0" Body="&lt;p&gt;This situation is probably caused by free Ca ions in the soil solution.&#xA;I've found an article that talks about high PBS.&#xA;Take a look at this reference, hope it helps&#xA;Tomašic, M., Zgorelec, Ž., Jurišic, A., &amp;amp; Kisic, I. (2013). Cation exchange capacity of dominant soil types in the Republic of Croatia. Journal of Central European Agriculture.&lt;/p&gt;&#xA;" OwnerUserId="28053" LastActivityDate="2022-11-28T18:35:22.570" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24571" PostTypeId="1" CreationDate="2022-11-28T20:08:26.373" Score="3" ViewCount="71" Body="&lt;p&gt;The Teglen (or Tiglian) interglacial period began after approximately half a million years into the Pleistocene, and the next interglacial (Waalian) occurred about a million years after that.&lt;/p&gt;&#xA;&lt;p&gt;But the last half-dozen or so interglacial periods have been spaced about 100,000 years apart, rather than 1,000,000 years.&lt;/p&gt;&#xA;&lt;p&gt;Is there a reason?  Or is there just not enough evidence of 'lesser' interglacials (or major interstadials?) during the early Pleistocene.&lt;/p&gt;&#xA;" OwnerUserId="20985" LastEditorUserId="81" LastEditDate="2022-12-29T15:21:22.257" LastActivityDate="2022-12-29T15:21:22.257" Title="Why were the Interglacial periods in the early Pleistocene spaced about one million years apart, but recent ones only 100,000 years apart?" Tags="|geophysics|ice-age|geologic-layers|milankovitch-cycles|age|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24572" PostTypeId="2" ParentId="24571" CreationDate="2022-11-28T21:40:07.407" Score="1" Body="&lt;p&gt;It was a transition from a 41000 year cycle to a 100000 year cycle that happened about a million years ago (the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mid-Pleistocene_Transition&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mid-Pleistocene Transition&lt;/a&gt;), not from a 1000000 year cycle to a 100000 year cycle. There have been guesses (lots of guesses), but no one knows the definitive answer to this yet. One that I like is that the earlier glaciations eventually scraped the northern Earth down to bedrock, thereby changing climate responses to Milankovitch cycles. There are however many, many other possible explanations for this shift.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2022-11-29T13:50:37.260" LastActivityDate="2022-11-29T13:50:37.260" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24573" PostTypeId="1" CreationDate="2022-11-29T07:46:56.903" Score="3" ViewCount="134" Body="&lt;p&gt;In a lecture we learned that instantaneously removing all clouds from earth would give radiation forcing of about 18W/m² [1], leading to significant warming. So clouds, in simple words, cool the earth significantly.&lt;/p&gt;&#xA;&lt;p&gt;However, in the same lecture we learned that clouds do have a positive feedback, which means (in my opinion), that by increasing temperature we have an increased amount of net radiation to earth. How is this to be understood? Does it mean that higher temperature gives rise to less clouds and therefore more net radiation?&lt;/p&gt;&#xA;&lt;p&gt;Somehow, this appears not very intuitive, because on the one hand clouds are &amp;quot;good for cooling&amp;quot;, on the other hand they have positive feedback, which is &amp;quot;worse for cooling&amp;quot;. Is there a way to understand this &amp;quot;tradeoff&amp;quot; on a pure qualitative level?&lt;/p&gt;&#xA;&lt;p&gt;I know, that clouds are quite complex and not well understood, but maybe there is a convincing explanation for that &amp;quot;discrepancy&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;[1] &lt;a href=&quot;https://journals.ametsoc.org/view/journals/clim/31/2/jcli-d-17-0208.1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://journals.ametsoc.org/view/journals/clim/31/2/jcli-d-17-0208.1.xml&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2022-11-29T08:27:32.863" LastActivityDate="2022-11-29T15:11:36.963" Title="Why do clouds have positive climate feedback although they have a cooling net effect?" Tags="|climate|climate-models|clouds|atmospheric-radiation|radiation-balance|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24574" PostTypeId="2" ParentId="24573" CreationDate="2022-11-29T14:16:56.287" Score="0" Body="&lt;p&gt;The &lt;a href=&quot;https://www.science.org/doi/10.1126/science.1192546&quot; rel=&quot;nofollow noreferrer&quot;&gt;cloud radiative feedback&lt;/a&gt;, as commonly referred to, is a measure of the clouds's effect on radiation change due to changes in temperature (i.e. &amp;quot;climate&amp;quot;):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Climate warming affects both cloud number and cloud properties, which in turn affect warming itself.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Clouds reflect shortwave radiation back to space, yes, but they also reflect longwave ratiation down, back to earth, warming the surface. Remember that water vapor is a natural greenhouse gas. Therefore clouds, or moisture in general, increase the greenhouse gas effect. This is illustrated in the image below taken from &lt;a href=&quot;https://earthobservatory.nasa.gov/features/EnergyBalance/page1.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;this website&lt;/a&gt;, referred to as &amp;quot;back radiation&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DzURl.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DzURl.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The net effect &lt;em&gt;seems to be positive&lt;/em&gt;, but uncertainties are large. &lt;a href=&quot;https://www.science.org/doi/10.1126/science.1192546&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dessler et al. (2010)&lt;/a&gt; estimate the cloud feedback magnitude at 0.54 plus/minus 0.74 (two standard deviations) (W/m^2)/K. Note that the uncertainties are larger than the mean estimate.&lt;/p&gt;&#xA;" OwnerUserId="8396" LastEditorUserId="8396" LastEditDate="2022-11-29T14:59:37.580" LastActivityDate="2022-11-29T14:59:37.580" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24575" PostTypeId="2" ParentId="24573" CreationDate="2022-11-29T14:42:32.533" Score="0" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;In a lecture we learned that instantaneously removing all clouds from earth would give radiation forcing of about 18W/m², leading to significant warming.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;First of all, this is non-physical. The Earth is about 70% ocean. The only way to eliminate all clouds from the atmosphere would be an Earth covered from pole to pole by ice. (This may have happened long ago, in the Cryogenic.) Water has an extremely low albedo, and land has a much lower albedo than clouds. Much of the Earth's roughly 30% albedo results from clouds. Magically removing all clouds (and this would require magic) would significantly reduce the Earth's albedo. That magic is the source of that increased radiative forcing. But it is not physical.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;However, in the same lecture we learned that clouds do have a positive feedback, which means (in my opinion), that by increasing temperature we have an increased amount of net radiation to earth. How is this to be understood?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I suspect you may have a misunderstanding of what &amp;quot;positive feedback&amp;quot; means. If you've ever attended a concert or speech where someone goes up to the microphone and says &amp;quot;testing, testing, testing&amp;quot;, they are testing whether the sound system is exhibiting positive feedback. Positive feedback is a bad thing in this regard. The &amp;quot;testing&amp;quot; turns into an awful screech if positive feedback is present. Positive feedbacks in climate science are things that magnify the effects of increased climate forcings. Negative feedbacks counteract the effects of increased climate forcings.&lt;/p&gt;&#xA;&lt;p&gt;Whether smallish increases or decreases in cloudiness is a positive or negative feedback has long been debated. (Keep in mind that 0% cloudiness is non-physical, so no one investigates this.) There apparently is a difference between high clouds versus low clouds, but the community is leaning toward increased cloudiness being a net positive feedback (a bad thing) rather than a net negative feedback (a good thing).&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-11-29T14:42:32.533" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24576" PostTypeId="2" ParentId="24573" CreationDate="2022-11-29T15:11:36.963" Score="1" Body="&lt;p&gt;The cloud radiative forcing and the cloud feedback are two separate properties of the climate system that both operate through various cloud mechanisms.  As that paper you cite shows in Table 5, overall cloud radiative forcing is split broadly into two opposing components: a shortwave forcing of -46 W/m2 (reflected solar radiation), and a longwave forcing of +28 W/m2 (thermal emission).  That gives a net cloud radiative forcing of -18 W/m2 at the top-of-atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;We need to be mindful of the sign conventions here.  You mention the removal of clouds giving a forcing of +18 W/m2, which is not wrong, but we normally frame this as the &lt;em&gt;addition&lt;/em&gt; or &lt;em&gt;presence&lt;/em&gt; of cloud giving a forcing of -18 W/m2.  That’s because we’re thinking of it as describing how clouds contribute to the long-term balanced state of the system, such as the pre-industrial state, rather than a “what if” experiment about them disappearing.&lt;/p&gt;&#xA;&lt;p&gt;Cloud (and other) feedbacks come into play when we think about what happens when something perturbs the radiative balance of the system from this baseline.  That something could be a change in GHG or aerosol concentrations, large-scale deforestation, a large volcanic eruption, solar output, etc.  This will cause changes to the system state through these feedback mechanisms that can either oppose or strengthen the original radiative perturbation.&lt;/p&gt;&#xA;&lt;p&gt;In the case of cloud feedbacks, those two opposing components (shortwave and longwave) could each change in either direction in response to a radiative perturbation, so the net effect of cloud feedbacks could also go in either direction.  Models disagree a lot about what the cloud net response to greenhouse gas increase is; the CMIP5 ensemble had -0.04±0.53 W/m2/K in response to a CO2 doubling, but individual models can go in either direction.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2022-11-29T15:11:36.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24577" PostTypeId="1" AcceptedAnswerId="24578" CreationDate="2022-12-01T01:47:49.473" Score="6" ViewCount="157" Body="&lt;p&gt;The CBS News' headline &lt;a href=&quot;https://www.cbsnews.com/news/hawaii-volcanoes-eruptions-mauna-loa-kilauea-sacred-event/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Two volcanoes erupt simultaneously in Hawaii for first time in decades: &amp;quot;A very sacred event that we are watching&amp;quot;&lt;/a&gt; suggests that simultaneous eruptions from these two volcanoes have happened at least once before in recent times, which suggests (to me at least) that this is not a random coincidence.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Dual eruptions haven't been seen &lt;a href=&quot;https://www.nps.gov/havo/planyourvisit/eruption-viewing.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;since 1984&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question:&lt;/strong&gt; Is there a causal relationship between the simultaneous eruptions of Mauna Loa and Kīlauea? Does one cause the other or perhaps a third phenomenon cause both?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HkCMu.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HkCMu.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;em&gt;Kīlauea (left) and Mauna Loa (right) erupting simultaneously on November 28, 2022, view from Kūpinaʻi Pali. NPS Photo/J.Ibasan, public domain.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="6031" LastEditorUserId="6031" LastEditDate="2022-12-06T04:37:33.810" LastActivityDate="2023-11-21T10:46:26.643" Title="Causal relationship between the simultaneous eruptions of Mauna Loa and Kīlauea? Does one cause the other or perhaps a third phenomenon cause both?" Tags="|volcanology|volcanic-eruption|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24578" PostTypeId="2" ParentId="24577" CreationDate="2022-12-01T10:03:18.707" Score="5" Body="&lt;p&gt;An article on this topic has recently been published: &lt;em&gt;Elastic interaction between Mauna Loa and Kīlauea evidenced by independent component analysis&lt;/em&gt; (&lt;a href=&quot;https://doi.org/10.1038/s41598-022-24308-0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Przeor et al., 2022&lt;/a&gt;). It begins:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The interaction processes between the two most active Hawaiian&#xA;volcanoes are still controversial, and despite multiple studies&#xA;carried out over more than a century, an unambiguous model has yet to&#xA;be identified.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Later, the two following paragraphs review some of those studies:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The interaction between the two most active volcanoes of Hawai‘i&#xA;Island has been discussed for over 100 years&lt;sup&gt;11&lt;/sup&gt;,&lt;sup&gt;12&lt;/sup&gt;,&lt;sup&gt;26&lt;/sup&gt;. Rhodes and&#xA;Hart&lt;sup&gt;27&lt;/sup&gt; confirm that the chemical composition of lavas at Kīlauea and&#xA;Mauna Loa are different, indicating the magmatic feeding systems are&#xA;independent (at least at the crustal level). However, geophysical&#xA;studies seem to indicate the opposite: Klein&lt;sup&gt;11&lt;/sup&gt; first noticed the&#xA;anticorrelation between the two volcanoes, emphasising that an&#xA;increase in activity at Kīlauea often corresponds to a decrease in&#xA;Mauna Loa dynamism. Miklius and Cervelli&lt;sup&gt;12&lt;/sup&gt; captured the opposite&#xA;behaviour in the ground deformation patterns of the volcanoes: at the&#xA;beginning of the high-volume effusive episode in Kīlauea, inflation of&#xA;Mauna Loa was observed (May 2002). Shirzaei et al.&lt;sup&gt;28&lt;/sup&gt; studied the&#xA;coupling behaviour of both volcanoes between 2003 and 2008. The&#xA;authors postulate that the causative source of the interaction between&#xA;the two volcanoes is related to deep-seated mantle surges. Despite&#xA;being the subject of many studies, the nature and the mechanism of the&#xA;interaction between the feeding systems of the two volcanoes and their&#xA;level of interconnection are still contentious and remain unclear.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Many authors have already suggested possible connections between Mauna&#xA;Loa and Kīlauea. Miklius and Cervelli&lt;sup&gt;12&lt;/sup&gt; proposed a crustal-level&#xA;interaction between them: pulses of magma in the plumbing system of&#xA;Mauna Loa may cause pressure variations in the Kīlauea shallow magma&#xA;system. Gonnermann et al.&lt;sup&gt;13&lt;/sup&gt; explained observed related ground&#xA;deformation patterns by considering a pore-pressure diffusion within a&#xA;thin accumulation layer in the asthenosphere. Since the magma&#xA;composition at Kīlauea is isotopically distinct from Mauna Loa&lt;sup&gt;27&lt;/sup&gt;,&#xA;Gonnermann et al.&lt;sup&gt;13&lt;/sup&gt; suggested the interconnection between Mauna Loa&#xA;and Kīlauea must be explained by the transfer of stress by&#xA;pore-pressure variations. Shirzaei et al.&lt;sup&gt;28&lt;/sup&gt; explain the&#xA;interconnection between the Mauna Loa magma chamber and the Kīlauea&#xA;rift zone through pore pressure diffusion in an asthenospheric magma&#xA;supply system.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This new study, based on deformation patterns of both Mauna Loa and Kīlauea, concludes:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;We highlight that the connection between Mauna Loa and Kīlauea occurs at shallow depths in the first few kilometers of the crust, through a stress transfer mechanism. [...] This interconnection is created by the Mauna Loa reservoir perturbing the Kīlauea shallowest source. Conversely, the sources below the Kīlauea do not effectively influence the Mauna Loa reservoir. In practice, the inflation of Mauna Loa makes the stress field in the surroundings of Kīlauea less favourable for the ascent of magma into its shallow reservoir.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In summary, according to this new study:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;There is a &amp;quot;connection&amp;quot; between the two volcanoes (or rather between their plumbing systems), but this connection works in one way only&lt;span class=&quot;math-container&quot;&gt;$-$&lt;/span&gt;Mauna Loa has an influence on Kīlauea, but the opposite is not true.&lt;/li&gt;&#xA;&lt;li&gt;This is not a physical connection of the plumbing systems (as in shared pipes), but rather a transfer of stress through the crust.&lt;/li&gt;&#xA;&lt;li&gt;This connection is actually an anticorrelation: when there is an overpressure in Mauna Loa magma reservoir (hence inflation of the volcano), there is a decrease in stress in Kīlauea's shallower reservoir.&lt;/li&gt;&#xA;&lt;li&gt;&lt;em&gt;But!&lt;/em&gt; Kīlauea has another, deeper reservoir which seems to be unaffected by this connection. Note that this reservoir is also connected to Kīlauea rift zones, so its magma can erupt without going through the upper reservoir.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;All in all, I'd say that each volcano works pretty much on its own, independently, or, to answer your question directly, that &lt;strong&gt;there is no causal relationship between the simultaneous eruptions of Mauna Loa and Kīlauea&lt;/strong&gt;. But we still don't know for sure. Despite being very well studied for more than a century, Kīlauea still holds some mysteries! The geometry of its plumbing system is not so well defined yet. The USGS carried out an Airborne Electromagnetic and Magnetic (AEM) survey this summer precisely to better constrain it, so we might have some answers soon!&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8RZF8.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8RZF8.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;em&gt;Telephoto image of the Airborne Electromagnetic and Magnetic (AEM) survey being flown over Kīlauea caldera on July 28, 2022. The South Sulphur Bank area is visible in the background of the image as a light-colored deposits on the left side. NPS Photo/J.Wei, public domain.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;Update&lt;/strong&gt;. Both eruptions have now ended, at about the same time. Here is a &lt;a href=&quot;https://www.facebook.com/USGSVolcanoes/posts/pfbid0GFZPtp7xAj4PU48p5fuB3RM8SRdmWZi3JRnjXKma1p9FS4fJYoDqgfUWpHmhUSEtl?__cft__%5B0%5D=AZV7rGo0XaWVThCe9ZwGLM4Gq8tXYWeVMxI67RHgJpgYBlakwsyh_igK1BBL_KL4KyNQ9iQ_op1BjSbhaJXZf48aN3Dzwn6KZp5l1llAdgkZ0e-aOmFPxZIKYOQ_ZGcaL4Eslu8tnLKiqtpxMiwietBFc537dqKdmJ8dR--pSxijVs0oxMf9cZuYXSdepsOGe8DN3AOCGb0MXO7a-XFT3cVk&amp;amp;__tn__=%2CO%2CP-R&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS statement&lt;/a&gt; about this situation:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Mauna Loa and Kīlauea have separate magmatic systems and are not connected at a shallow level. But it remains possible that the volcanoes can influence one another through stresses associated with their eruptions—essentially, when one volcano expands or contracts, it can put pressure on (or take pressure off!) the other volcano. [...] Removal of magma from Mauna Loa’s reservoir by the recent eruption may have allowed Kīlauea to relax. Because Kīlauea’s eruption was occurring at such a low rate, it could have been more susceptible to the small changes in stress that were caused by Mauna Loa’s eruption. However, it is also possible that the change in Kīlauea’s eruptive behavior is a coincidence—with such low levels of activity at Kīlauea prior to Mauna Loa’s eruption, it is difficult to be certain. And of course this may only represent a temporary pause in Kīlauea’s activity.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;Update #2&lt;/strong&gt;. Two new studies have been published on the subject of &amp;quot;connected&amp;quot; volcanoes (although not in Hawaii). &lt;a href=&quot;https://doi.org/10.1016/j.jvolgeores.2023.107892&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kiryukhin et al. (2023)&lt;/a&gt; describes how Bezymianny eruptions are actually fed by nearby Klyuchevskoy magma chamber. &lt;a href=&quot;https://doi.org/10.1038/s41467-023-42157-x&quot; rel=&quot;nofollow noreferrer&quot;&gt;Reddin et al. (2023)&lt;/a&gt; shows that &lt;em&gt;six&lt;/em&gt; (!) volcanoes from the Galápagos Islands are connected through interconnected magmatic systems.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2023-11-21T10:46:26.643" LastActivityDate="2023-11-21T10:46:26.643" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24579" PostTypeId="2" ParentId="118" CreationDate="2022-12-01T13:58:02.150" Score="1" Body="&lt;p&gt;The main difference between archaeology and geological stratigraphy is the archaeological deposits are unbound sediments that are dug and, in geology, some samples or fossils are taken to describe the outcrops, but the main tasks are description and correlation, while in archaeology the main tasks are only digging and description.&lt;/p&gt;&#xA;&lt;p&gt;The other huge difference as you mention is the geological ages are based in &lt;a href=&quot;https://stratigraphy.org/chart&quot; rel=&quot;nofollow noreferrer&quot;&gt;chronostratigraphic chart&lt;/a&gt;, which is based in geological events, and the archaeological ages are based in the kind of tools the human used in the prehistory and the history.&lt;/p&gt;&#xA;&lt;p&gt;Dating methods to estimate the ages are done by the same principles, but a geological age covers millions of years and the epsilon is not so important, being more easy to grant an age to a level in the chronostratigraphic chart.&lt;/p&gt;&#xA;&lt;p&gt;There are differences in how strata are correlated in both sciences. While in geology spatial correlation can be as large as the whole world (for example for the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cretaceous%E2%80%93Paleogene_extinction_event&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cretaceous-Paleogene mass extinction&lt;/a&gt;, where a level enriched in iridium is seen in different places all over the Earth), archaeology correlation is based on the spatial distribution of human populations with similar culture, less extensive in the spatial dimension.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Is geological stratigraphy visualized with Harris matrix or something very similar too?&#xA;Is geological stratigraphy simpler, so some archaeological stratigraphy rules don't apply?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The Harris Matrix and other techniques and principles used in archaeology are sophisticated and not used in geological stratigraphy. In archaeological stratigraphy the level of detail of the description of the succession is higher, becoming essential to correctly establish a detailed register succession.&lt;/p&gt;&#xA;" OwnerDisplayName="user27958" LastEditorUserId="2470" LastEditDate="2022-12-01T18:43:00.263" LastActivityDate="2022-12-01T18:43:00.263" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24580" PostTypeId="1" AcceptedAnswerId="24633" CreationDate="2022-12-01T19:42:40.660" Score="2" ViewCount="95" Body="&lt;p&gt;Pretty much what the title says. For my work I need historic (at least starting 2010), atmospheric weather data (mostly temperature at 2m, wind velocity and direction, humidity respectively dewpoint, nothing fancy) in &lt;em&gt;hourly frequency&lt;/em&gt; and ERA5 delivers that globally and conveniently via free API access.&lt;/p&gt;&#xA;&lt;p&gt;But I'd like to concentrate on areas with high population density (basically large cities) and I'm a bit afraid, that the ~30km grid of ERA5 is a bit too coarse to capture that accurately, especially for cities with a very high population density in a smaller area, as it is often the case for old European cities.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Does anyone know a data source that can offer this weather data on a higher resolution grid (10km, 5km, ...?) but with otherwise similar features as the ERA5 data (variables, frequency, access, ...)?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Degrees of Freedom:&lt;/strong&gt; I'm fine if the coverage would be &lt;em&gt;restricted&lt;/em&gt; to urban centers, I'm not interested in rural areas. Equally, if such data would only be available in parts of the world (e.g. only Europe or only North America), that would be acceptable if not ideal.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Restrictions:&lt;/strong&gt; However, I'm &lt;em&gt;not&lt;/em&gt; interested in just a collection of 'local' weather stations because I need to avoid any bias from any uncorrected measurements below blending height. I do not have the capability to do such corrections myself and due to the nature of my work I need a 'synoptic' base for my data. For example wind velocity at 10m should be provided in a similar fashion as by ERA5: with a roughness factor of grass, since I'd like to introduce my own surface parameters instead. (Ref: &lt;a href=&quot;https://confluence.ecmwf.int/display/FUG/9.3+Surface+Wind&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://confluence.ecmwf.int/display/FUG/9.3+Surface+Wind&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Possible Workaround:&lt;/strong&gt; Im not very well versed in ERA5 data (not meteorologist by training), so there might be a way to extract this data from the model by accessing sub-grid information in some way?&lt;/p&gt;&#xA;&lt;p&gt;Currently I'm using code like this to grab my data:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;...&#xA;cdsclientrequest.retrieve(&#xA;    'reanalysis-era5-single-levels',&#xA;    {&#xA;        'product_type': 'reanalysis',&#xA;        'format': 'grib',&#xA;        'variable': climatevars,&#xA;        'area': bbox.bbox,&#xA;        'year': year,&#xA;        'month': month,&#xA;        'day': times.day,&#xA;        'time': times.time,&#xA;    },&#xA;    filepath)&#xA;...&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;I hope this makes sense, if not please ask! I'm thankful for any tips!&lt;/p&gt;&#xA;" OwnerUserId="27444" LastActivityDate="2022-12-15T08:24:15.380" Title="Where can I find high-resolution, historic weather data for urban areas (like ERA5 but higher spatial resolution)?" Tags="|meteorology|mesoscale-meteorology|grid-spacing|urban-climate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24582" PostTypeId="1" CreationDate="2022-12-02T08:58:13.210" Score="2" ViewCount="18" Body="&lt;p&gt;Where can I find a table with the geochemical threshold for potentially toxic elements in the soils of Spain? I only have seen a decree with organic compounds for Spain.&lt;/p&gt;&#xA;" OwnerUserId="20981" LastActivityDate="2022-12-02T08:58:13.210" Title="Searching for Geochemical Threshold for PTE's of Spain" Tags="|geochemistry|soil|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24583" PostTypeId="2" ParentId="3122" CreationDate="2022-12-04T09:09:15.193" Score="1" Body="&lt;p&gt;If you don't mind loosening your definition of &amp;quot;ore&amp;quot; or changing it to include dimension stone, &lt;a href=&quot;https://en.wikipedia.org/wiki/Lutetian_limestone&quot; rel=&quot;nofollow noreferrer&quot;&gt;limestone&lt;/a&gt; was mined under &lt;a href=&quot;https://en.wikipedia.org/wiki/Mines_of_Paris&quot; rel=&quot;nofollow noreferrer&quot;&gt;Paris&lt;/a&gt;, France to provide material for the construction of buildings. The result of which is many nice buildings in Paris, but also a network of catacombs beneath the city.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WnXup.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WnXup.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Not a mineral or a solid, but &lt;a href=&quot;https://en.wikipedia.org/wiki/Los_Angeles_City_Oil_Field&quot; rel=&quot;nofollow noreferrer&quot;&gt;Los Angeles&lt;/a&gt; is on top of an oil field that is actively being extracted.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mwhJY.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mwhJY.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;These days, the &lt;a href=&quot;https://www.lamag.com/citythinkblog/hidden-oil-wells/&quot; rel=&quot;nofollow noreferrer&quot;&gt;oil rigs are hidden&lt;/a&gt; within what appears to be &lt;a href=&quot;https://99percentinvisible.org/article/hollywood-worthy-camouflage-uncovering-the-urban-oil-derricks-of-los-angeles/&quot; rel=&quot;nofollow noreferrer&quot;&gt;buildings&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;In Australia, &lt;a href=&quot;https://visitsydneyaustralia.com.au/lost-coalmines.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sydney&lt;/a&gt; and many other cities and towns were established over coal fields.&lt;/p&gt;&#xA;&lt;p&gt;There is also the &lt;a href=&quot;https://Kupferschiefer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kupferschiefer&lt;/a&gt; (copper shale) deposit of northern Europe, from the North Sea to Poland, which has been mined in Lubin, Poland.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2022-12-04T09:35:34.107" LastActivityDate="2022-12-04T09:35:34.107" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24585" PostTypeId="1" AcceptedAnswerId="24586" CreationDate="2022-12-04T20:26:58.930" Score="5" ViewCount="858" Body="&lt;p&gt;Having in mind the absorption of IR radiation by various atmospheric gases, why is there almost no outgoing radiation into space where absorption is strong?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7U7vg.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7U7vg.png&quot; alt=&quot;Enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;At the &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; 15um wavelength, there is almost no outgoing radiation. OK, it sounds logical, because &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; absorbs that range of radiation.&lt;/p&gt;&#xA;&lt;p&gt;But since &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; is a good absorber, according to &lt;a href=&quot;https://en.wikipedia.org/wiki/Kirchhoff%27s_law_of_thermal_radiation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kirchhoff's law&lt;/a&gt; it should be a good emitter at the same wavelengths.&lt;/p&gt;&#xA;&lt;p&gt;The radiation equation in its simplest form says:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$I_\nu = I_\nu(0) e^{-\tau\nu} + I_\nu^B [1-e^{-\tau_\nu}]$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0LLc3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0LLc3.png&quot; alt=&quot;Enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I understand that when the optical thickness is large, the outgoing radiation is dominated by the &lt;span class=&quot;math-container&quot;&gt;$I_\nu^B$&lt;/span&gt;, the Boltzmann value for black-body radiation.&lt;/p&gt;&#xA;&lt;p&gt;When the atmosphere is optically thick, we would have this situation and, therefore, according to that picture, there should be outgoing radiation also at those wavelengths. Even taking into account the lower temperature of the atmosphere can, in my opinion, not explain, why outgoing radiation is almost zero.&lt;/p&gt;&#xA;&lt;p&gt;But why is this the case?&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="502" LastEditDate="2022-12-08T21:18:04.863" LastActivityDate="2022-12-10T23:24:49.953" Title="Why doesn't earth radiate at wavelengths where there is strong absorption?" Tags="|atmosphere|greenhouse-gases|atmospheric-radiation|radiation-balance|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24586" PostTypeId="2" ParentId="24585" CreationDate="2022-12-04T21:40:26.467" Score="6" Body="&lt;p&gt;Due to the large optical thickness, the outgoing radiation is emitted at stratospheric temperatures (the black-bodies indicated by ~210K temperatures).&lt;/p&gt;&#xA;&lt;p&gt;Keep in mind that the black-bodies in the graph are scaled by their total integral, i.e. some constant &lt;span class=&quot;math-container&quot;&gt;$\times T^4$&lt;/span&gt;. Therefore, the emission surface at 210K emits at way lower fluxes than the balmy, room-temperature black-body on the surface, where the atmospheric window signal is coming from.&lt;/p&gt;&#xA;&lt;p&gt;I strongly presume that this graph has a linear axis in the y-direction, which heavily suppresses the low flux values. It also depends whether the flux &lt;span class=&quot;math-container&quot;&gt;$F_{\lambda}$&lt;/span&gt; with units &lt;span class=&quot;math-container&quot;&gt;$[F_{\lambda}] = J  s^{-1} m^{-2} A^{-1}$&lt;/span&gt; or the energy density &lt;span class=&quot;math-container&quot;&gt;$\lambda F_{\lambda}$&lt;/span&gt; with units &lt;span class=&quot;math-container&quot;&gt;$[\lambda F_{\lambda}] = J  s^{-1} m^{-2}$&lt;/span&gt; is plotted, which can suppress long-wavelength features.&lt;/p&gt;&#xA;&lt;p&gt;I guess the usual view of Earth's emission spectrum I would have can be seen in some plots &lt;a href=&quot;https://wattsupwiththat.com/2011/03/10/visualizing-the-greenhouse-effect-emission-spectra/&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;, where the 15 micron suppression is clearly visible (as is the inversion inside the feature - a telltale of the temperature structure in the atmosphere).&lt;/p&gt;&#xA;&lt;p&gt;So TLDR: My money is on some scaling issue, as this plot is supposed to be the simple one, for public consumption.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2022-12-04T21:40:26.467" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24587" PostTypeId="2" ParentId="24569" CreationDate="2022-12-05T08:47:30.687" Score="2" Body="&lt;p&gt;Look at the &lt;a href=&quot;https://www.aanda.org/articles/aa/pdf/2004/46/aa1335.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;article they cite&lt;/a&gt; as the source of their computations. It's a model that's meant to be valid across hundreds of millions of years, &lt;em&gt;only based on orbital parameters&lt;/em&gt; (changes in Earth's rotation, axial tilt, distance from the sun, dates of aphelion/perihelion, etc). These are all parameters that only change significantly over the course of tens of thousands of years. The idea is to understand that, due to those orbital changes, some places on Earth may have gotten, on average, more or less sun in the past than they do  now (e.g. the current near-alignment of perihelion with the northern winter solstice was opposite at some time in the past, resulting in a different balance of insolation between the northern and southern hemispheres).&lt;/p&gt;&#xA;&lt;p&gt;What it &lt;em&gt;doesn't&lt;/em&gt; model is the actual radiation output of the sun, known as &lt;a href=&quot;https://en.wikipedia.org/wiki/Solar_constant&quot; rel=&quot;nofollow noreferrer&quot;&gt;solar constant&lt;/a&gt;. Solar output varies over shorter timescales (with significant oscillations having periods between 10 and 1000 years, and some unpredictable dynamics over a scale of months to decades), but this variation isn't included in the model on that page, it's simply averaged out.&lt;/p&gt;&#xA;" OwnerUserId="4720" LastActivityDate="2022-12-05T08:47:30.687" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24588" PostTypeId="1" CreationDate="2022-12-05T10:21:21.010" Score="3" ViewCount="57" Body="&lt;p&gt;I am new to oceanography. As per the practical scenario, what is the range of wave number and wave frequency values? Thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="28085" LastActivityDate="2022-12-27T20:52:53.567" Title="Ranges of Ocean wave number and Ocean wave frequency" Tags="|oceanography|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24591" PostTypeId="1" CreationDate="2022-12-06T09:10:38.623" Score="1" ViewCount="32" Body="&lt;p&gt;I want to make an app for first courses geology students that include the types of volcanoes and eruptions.&lt;/p&gt;&#xA;&lt;p&gt;Can you recommend me a book (in English, French or Spanish) that could help me make the students learning process more profitable?&lt;/p&gt;&#xA;&lt;p&gt;It should contain designs to do my own work with &lt;a href=&quot;https://inkscape.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;inkscape&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user27958" LastEditorDisplayName="user27958" LastEditDate="2022-12-06T09:19:32.470" LastActivityDate="2023-01-06T17:03:49.200" Title="Volcanology book to make an app for first courses students" Tags="|geology|volcanology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24592" PostTypeId="1" CreationDate="2022-12-06T10:54:57.097" Score="2" ViewCount="29" Body="&lt;p&gt;I want to make a structural geology app for first courses geology and minning students.&lt;/p&gt;&#xA;&lt;p&gt;I want a book that list the structures as folds and faults to do my own designs with &lt;a href=&quot;https://inkscape.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;inkscape&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Can you recommend me a book (in English, French or Spanish)?&lt;/p&gt;&#xA;" OwnerDisplayName="user27958" LastActivityDate="2022-12-06T10:54:57.097" Title="Structural geology book to make an app for first courses students" Tags="|structural-geology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24594" PostTypeId="1" CreationDate="2022-12-06T14:26:57.037" Score="6" ViewCount="275" Body="&lt;p&gt;I'm looking to better understand the following statement on the reliability of weather forecasts from NOAA's SciJink:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A seven-day forecast can accurately predict the weather about 80&#xA;percent of the time and a five-day forecast can accurately predict the&#xA;weather approximately 90 percent of the time. However, a 10-day—or&#xA;longer—forecast is only right about half the time.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;source &lt;a href=&quot;https://scijinks.gov/forecast-reliability/#:%7E:text=The%20Short%20Answer%3A,right%20about%20half%20the%20time&quot; rel=&quot;noreferrer&quot;&gt;https://scijinks.gov/forecast-reliability/#:~:text=The%20Short%20Answer%3A,right%20about%20half%20the%20time&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;In this context what metric / threshold is used to evaluate, &amp;quot;&lt;strong&gt;can accurately predict the weather&lt;/strong&gt;&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="26668" LastActivityDate="2022-12-07T13:15:56.583" Title="Weather Forecast prediction accuracy metric" Tags="|meteorology|weather-forecasting|predictability|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24595" PostTypeId="1" AcceptedAnswerId="24596" CreationDate="2022-12-06T17:46:00.777" Score="7" ViewCount="5433" Body="&lt;p&gt;I watched a documentary about research on the coasts of Greenland where the sea level has &lt;em&gt;fallen&lt;/em&gt;. According to the research, this is because a lot of the glaciers have melted, resulting in less weight on the land and a upward push by the magma under Greenland.&lt;/p&gt;&#xA;&lt;p&gt;I'm wondering whether the US East Coast could also rise if all the people living there were to move away far enough for the weight to decrease. Since there are some 100 million people living there, I would imagine that's a lot of weight. However, I am thinking that since the inland US is part of a large continent, the magma would not be able to push it up like a &amp;quot;small&amp;quot; island like Greenland.&lt;/p&gt;&#xA;&lt;p&gt;Do we currently have sufficient metrics to calculate such movements with fairly good accuracy?&lt;/p&gt;&#xA;&lt;p&gt;Here is an article for reference:&#xA;&lt;a href=&quot;https://www.sciencenews.org/article/jacky-austermann-climate-sn-10-scientists-to-watch&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencenews.org/article/jacky-austermann-climate-sn-10-scientists-to-watch&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28092" LastEditorUserId="-1" LastEditDate="2022-12-08T00:28:37.040" LastActivityDate="2022-12-08T00:28:37.040" Title="Would the US East Coast rise if everyone living there moved away?" Tags="|climate-change|plate-tectonics|sea-level|" AnswerCount="2" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="24596" PostTypeId="2" ParentId="24595" CreationDate="2022-12-06T22:06:28.750" Score="18" Body="&lt;p&gt;The mass of human bodies across the US East coast (about 120 million for the East coast States) is very small compared to Greenland ice mass loss, which (according to Grace Satellite data) has averaged 273 billion metric tons per year since 2002 - about 5 trillion tons over the last 20 years, ie about 1/40,000th based on a generous body mass of 100kg (it is closer to 80kg) if my arithmetic is correct. (I had to edit because my arithmetic &lt;em&gt;wasn't&lt;/em&gt; first time around).&lt;/p&gt;&#xA;&lt;p&gt;I don't know if that would make a &lt;em&gt;measurable&lt;/em&gt; difference to the gravity effect of land masses on nearby sea levels - that depends on how accurate the measurements - but it won't be &lt;em&gt;significant&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The mass of buildings, cars trucks, machinery would be larger than that but a lot of that mass would be made out of materials like gravels and sands that were mined locally. Again, it won't be significant.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pwc3y.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pwc3y.png&quot; alt=&quot;Greenland Ice Mass Loss&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="18145" LastEditDate="2022-12-06T22:18:19.627" LastActivityDate="2022-12-06T22:18:19.627" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24597" PostTypeId="2" ParentId="24594" CreationDate="2022-12-07T06:39:30.943" Score="1" Body="&lt;p&gt;It comes down to data, time and computer modelling. Putting a confidence level on weather forecasts was not possible 30 to 40 years because of the lack of data and computer modelling capabilities.&lt;/p&gt;&#xA;&lt;p&gt;Meteorologists weren't able to predict hurricanes/cyclones/typhoons until the advent of weather satellites in the 1960s. These days meteorologists have a significant amount of current data available to them because of data gathering methods such as satellites, ocean buoys, etc. They also have benefited from fast and reliable data dissemination methods provided by the internet and from global weather observation databases continuously updated available for use.&lt;/p&gt;&#xA;&lt;p&gt;Access to inexpensive high powered computers running various computer models forecasting the weather, using all the latest data is key. Weather systems are dynamic, they can change quickly. This is where time is a factor. Predicting weather for the next few days is more reliable than doing do for several days ahead.&lt;/p&gt;&#xA;&lt;p&gt;No matter how good computer models are they can only consider so much, so they each have their own level of biases and inaccuracies. This is why a number of computer model are run to forecast weather; depending on the weather service, usually at least four.&lt;/p&gt;&#xA;&lt;p&gt;Each model takes the latest data and runs scenarios of what pressure systems might look like and where frontal systems might be as time passes. The more models that agree with each other the higher the confidence that meteorologists have concerning weather forecasts.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-12-07T06:39:30.943" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24598" PostTypeId="2" ParentId="24594" CreationDate="2022-12-07T12:17:47.480" Score="3" Body="&lt;p&gt;The climatological forecast for 1 July 2023 for some region is computed as follows, based on the meteorological record for that region and that date:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The predicted high is the average high for that date from all of the meteorological stations in that area, possibly weighted by some weighting scheme.&lt;/li&gt;&#xA;&lt;li&gt;The predicted low is the average low for that date from all of the meteorological stations in that area, again possibly weighted by some weighting scheme.&lt;/li&gt;&#xA;&lt;li&gt;The chance of precipitation is the product of the percentage of past first of July records where any weather station in the area measured a significant amount of precipitation multiple by the percentage of weather stations that did observe precipitation on those days.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The question then becomes how skillful is a forecast based on current and recent meteorological data compared to the climatological forecast? If it's a coin toss which of the two will be closer to observation, one might as well use the climatological forecast. This coin toss boundary currently is about where a ten days. The coin toss boundary used to be at seven days. Before then, it was four or five days, before that, just two or three days, then just one day. Before that, it was weather adages such as &amp;quot;red sky at night, sailors' delight,&amp;quot; which itself is a bit of a coin toss.&lt;/p&gt;&#xA;&lt;p&gt;A more qualitative approach is a skill score. For example, suppose the meteorological forecast for the high temperature for some day in the future is &lt;span class=&quot;math-container&quot;&gt;$H_f$&lt;/span&gt; (f for forecast) while the climatological forecast is &lt;span class=&quot;math-container&quot;&gt;$H_r$&lt;/span&gt; (r for reference). Wait until that day passes and note the actual high temperature &lt;span class=&quot;math-container&quot;&gt;$H_p$&lt;/span&gt;. The skill score for the meteorological forecast is &lt;span class=&quot;math-container&quot;&gt;$$SS_H = \frac{H_f - H_r}{H_p - H_r}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;There are multiple schemes by which skill scores for multiple scores, multiple metrics, and multiple regions are combined. Weather forecasts are a bit more skillful at predicting high and low temperatures than they are at predicting chance of precipitation. I'm not sure what combination scheme is used in determining that the ten day forecast remains a coin toss compared to the climatological forecast.&lt;/p&gt;&#xA;&lt;p&gt;References:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://journals.ametsoc.org/downloadpdf/journals/mwre/117/3/1520-0493_1989_117_0572_ssacci_2_0_co_2.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Murphy, Allan H., and Edward S. Epstein. &amp;quot;Skill scores and correlation coefficients in model verification.&amp;quot; Monthly weather review 117.3 (1989): 572-582.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.lse.ac.uk/CATS/Assets/PDFs/Publications/Papers/2019/Interpreting-the-skill-score-form-of-forecast-performance-metrics.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wheatcroft, Edward. &amp;quot;Interpreting the skill score form of forecast performance metrics.&amp;quot; International Journal of Forecasting 35.2 (2019): 573-579.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2022-12-07T13:15:56.583" LastActivityDate="2022-12-07T13:15:56.583" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24599" PostTypeId="2" ParentId="24595" CreationDate="2022-12-07T21:37:02.263" Score="7" Body="&lt;p&gt;While the weight of the population removed might not have much effect, stopping the removal of groundwater could potentially have a fairly large effect on the height relative to sea level. Lots of places are subject to &amp;quot;land subsidence&amp;quot;, which is the vertical sinking of land due to groundwater removal and subsequent settling. The most notable example I have heard about recently is Jakarta, but other arid places also suffer from it. The east coast doesn't count as arid, but the USGS claims that 45 US states suffer from it, so it stands to reason that some of those are on the East coast&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.usgs.gov/special-topics/water-science-school/science/land-subsidence#overview&quot; rel=&quot;noreferrer&quot;&gt;https://www.usgs.gov/special-topics/water-science-school/science/land-subsidence#overview&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28097" LastActivityDate="2022-12-07T21:37:02.263" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24600" PostTypeId="1" AcceptedAnswerId="24601" CreationDate="2022-12-08T08:18:57.327" Score="3" ViewCount="188" Body="&lt;p&gt;I spent already days on the following: In one of my meteorology scripts the equations for conservation of momentum in the rotation reference system of earth are given by:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GctmI.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GctmI.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The apparent forces are in orange, the others are clear.&lt;/p&gt;&#xA;&lt;p&gt;I wonder why there is no centrifugal force, however, the apparent force in a rotating system should be the sum of Coriolis and centrifugal force.&lt;/p&gt;&#xA;&lt;p&gt;To learn more about the derivation of these equations I studied this video carefully:&#xA;&lt;a href=&quot;https://www.youtube.com/watch?v=nljud2UiWUk&amp;amp;list=PL_cuIb7hx5lg_zHfUVsUrw6I66U4jq8Dq&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=nljud2UiWUk&amp;amp;list=PL_cuIb7hx5lg_zHfUVsUrw6I66U4jq8Dq&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;At it's end, the equations are written down:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DOe5j.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DOe5j.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;First I'm surprised that there are &amp;quot;curvature&amp;quot; forces: In my opinion they are nothing else but the centrifugal forces, but usually the total acceleration a' seen in a rotating system is written down as&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\vec a' = -\vec \omega \times \left(\vec \omega \times \vec r' \right) - 2 \cdot \vec \omega \times \vec v' \tag{1}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;First term is called usually &amp;quot;centrifugal force&amp;quot; while the right term is the Coriolis force.&#xA;But when I consider motion with (zonal) velocity u (along the east) on the equator, the total centrifugal force in radial direction z would be&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$a_z = \frac{(u+\omega R)^2}{R} = \omega^2R+u^2/R+2 \omega \cdot u \tag{2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;because the total tangential speed is the sum of earth's rotation and zonal speed.&lt;/p&gt;&#xA;&lt;p&gt;Now I wonder, where the quadratic term would be derived from equation (1). I see only the first and third term arising from (1) but not the middle...&lt;/p&gt;&#xA;&lt;p&gt;It seems a bit, that the u,v,w-driven part of what I call &amp;quot;centrifugal force&amp;quot; is absorbed into the Coriolis force and when we speak about centrifugal force only the static part of it (u=v=0) is regarded.&lt;/p&gt;&#xA;&lt;p&gt;However, when this is the case, there is still one missing thing: when u=v=w=0 we have a point at rest in earth's reference frame. At a given northern latitude &lt;span class=&quot;math-container&quot;&gt;$\phi$&lt;/span&gt; there is clearly a centrifugal force which doesn't point in pure z-direction but also has a y-component, pointing south:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$F_y = \Omega^2 R \cos(\phi) \sin(\phi)$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;so I would expect this as a &amp;quot;static&amp;quot; part of the second equations for &lt;span class=&quot;math-container&quot;&gt;$Dv/dt$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;However, in neither in the first image (my script) nor in the second one (the video) such component is identified: everything is proportional to u,v,w without a static component.&lt;/p&gt;&#xA;&lt;p&gt;Even worse, in the first image (taken from my lecture) the centrifugal forces are missing completely.&lt;/p&gt;&#xA;&lt;p&gt;Final questions in particular:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;How do quadratic terms arise from (1)?&lt;/li&gt;&#xA;&lt;li&gt;Where have centrifugal components gone to in the first image? It drives me nuts...&lt;/li&gt;&#xA;&lt;li&gt;Why &amp;quot;curvature force&amp;quot; when everywhere else (in my physics textbooks) total force is split just into centrifugal and Coriolis? Is there a new basic force &amp;quot;curvature&amp;quot; which I have overseen previously or is is just a matter of definition of whether we assign some mathematically arising components to &amp;quot;Coriolis&amp;quot; or &amp;quot;centrifugal&amp;quot;?&lt;/li&gt;&#xA;&lt;li&gt;Could it be, that centrifugal force is just the &amp;quot;static&amp;quot; centrifugal force due to earth's rotation and the other components are distributed along linear  and quadratic terms, where the quadratic terms are called &amp;quot;curvature forces&amp;quot; and the linear ones &amp;quot;Coriolis&amp;quot;. Something here is not consistent with my textbook knowledge I learned in the past.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2022-12-08T10:29:02.760" LastActivityDate="2022-12-08T10:52:52.700" Title="How is centrifugal force identified in equations of fluid motion in the rotating reference system of earth?" Tags="|meteorology|atmosphere-modelling|earth-rotation|fluid-dynamics|coriolis|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24601" PostTypeId="2" ParentId="24600" CreationDate="2022-12-08T10:52:52.700" Score="3" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;I wonder why there is no centrifugal force, however, the apparent force in a rotating system should be the sum of Coriolis and centrifugal force.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;There is a centrifugal acceleration in those equations. What we call &amp;quot;gravity&amp;quot; in a lay sense is a combination of gravitational acceleration and centrifugal acceleration. In a technical sense, what we call &amp;quot;gravity&amp;quot; is the acceleration of a free-falling body at sea level as observed in a frame of reference fixed with respect to the rotating Earth. Centrifugal acceleration is baked into &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;This means centrifugal acceleration is present in your equations. In particular, it is in your equation (3) as &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt;. If one takes &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; as a constant, &lt;span class=&quot;math-container&quot;&gt;$g_0=9.80665\,\text{m}/\text{s}^2$&lt;/span&gt; (which may be a bad idea), that's the acceleration due to gravitation and centrifugal forces at roughly the latitude of Paris. What we call &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; varies with latitude and with height above the ellipsoid, plus minor local perturbations. (Gravity near the Himalaya can get quite complex if one wants to be very precise.)&lt;/p&gt;&#xA;&lt;p&gt;A fairly simple approximation that accounts for latitude (but not height) is the Somigliana gravity formula,&lt;span class=&quot;math-container&quot;&gt;$$g = g_{\text{eq}}\frac{1+\kappa \sin^2\phi}{\sqrt{1-e^2\sin^2 \phi}}$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$g_{\text{eq}} = 9.7803267714\,\text{m}/\text{s}^2$&lt;/span&gt; is the acceleration due to gravity (including centrifugal acceleration) at the equator, &lt;span class=&quot;math-container&quot;&gt;$\kappa = 0.00193185138639$&lt;/span&gt;, which reflects the observed difference between gravity at the equator versus the poles, &lt;span class=&quot;math-container&quot;&gt;$e^2=0.00669437999013$&lt;/span&gt; is the square of the eccentricity of the figure of the Earth, and &lt;span class=&quot;math-container&quot;&gt;$\phi$&lt;/span&gt; is the geodetic latitude.&lt;/p&gt;&#xA;&lt;p&gt;The variation with height (the &amp;quot;free air correction&amp;quot;) is approximately linear in the Earth's atmosphere, a decrease of about &lt;span class=&quot;math-container&quot;&gt;$3.086\,\text{μm}/\text{s}^2$&lt;/span&gt; for every meter above sea level. If you are using &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; as a constant, you are essentially ignoring both the latitude and altitude corrections. Centrifugal acceleration is baked in. If you are using the Somigliana formula (or some other approximation of gravitation at sea level as a function of latitude), centrifugal acceleration is once again baked in.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-12-08T10:52:52.700" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24602" PostTypeId="1" AcceptedAnswerId="24603" CreationDate="2022-12-08T15:09:42.623" Score="3" ViewCount="500" Body="&lt;p&gt;In the foliation of a gneiss for instance, minerals are segregated by composition.&lt;/p&gt;&#xA;&lt;p&gt;What causes minerals phases to be grouped into layers like this?&lt;/p&gt;&#xA;" OwnerUserId="27711" LastEditorDisplayName="user27958" LastEditDate="2022-12-08T18:48:23.840" LastActivityDate="2022-12-09T00:38:29.040" Title="What causes compositional banding in metamorphic rocks?" Tags="|mineralogy|metamorphism|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24603" PostTypeId="2" ParentId="24602" CreationDate="2022-12-09T00:38:29.040" Score="5" Body="&lt;p&gt;There are several different ways in which gneissic banding can form. The three most common mechanisms are:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;strong&gt;Preservation of banding from source material&lt;/strong&gt;: Consider a protolith that already contains bands of different compositions, for example a sedimentary rock that formed through deposition of alternating layers of felsic and mafic minerals. These bands are then preserved during metamorphisis.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Compression and Shearing&lt;/strong&gt;: Consider a protolith composed of one mineral with inclusions of a different mineral. In the first stage of metamorphism, the rock undergoes compression, which causes the crystals of both minerals to align along their narrowest axis. In a second stage, the rock then undergoes shearing, which further elongates the crystals, leading to gneissic bands.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Chemical metamorphic differentiation&lt;/strong&gt;: Another possibility is that a chemical process results in the separation of minerals. Conditions during metamorphism such as the intrusion of fluids can cause certain layers or minerals in the protolith to preferentially dissolve, and later crystalize in specific sections of the rock, forming banded structures.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Sources: &lt;a href=&quot;https://www2.tulane.edu/%7Esanelson/eens212/metatexture.htm&quot; rel=&quot;noreferrer&quot;&gt;Metamorphic Textures, Stephen A. Nelson&lt;/a&gt;,&#xA;&lt;a href=&quot;https://books.google.de/books/about/Earth.html?id=moP9oAEACAAJ&amp;amp;redir_esc=y&quot; rel=&quot;noreferrer&quot;&gt;Portrait of a Planet, Marshak&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28104" LastActivityDate="2022-12-09T00:38:29.040" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24604" PostTypeId="2" ParentId="24159" CreationDate="2022-12-09T05:54:09.010" Score="2" Body="&lt;p&gt;It's been many months since August, but maybe someone else will find this useful.&lt;/p&gt;&#xA;&lt;p&gt;Like a lot of questions in hydrology - the appropriate boundary condition is defined by accurately characterizing the subsurface system. If limited data is available, it's probably best to run both boundary conditions and look at the sensitivity of the assumption and then determine if the conservative answer in the condition is reasonable (maybe to be revised with more detailed characterization later).&lt;/p&gt;&#xA;&lt;p&gt;In terms of the boundary conditions themselves:&lt;/p&gt;&#xA;&lt;p&gt;A seepage face requires a bottom layer to reach saturation before water is allowed to transmit to a lower level or to escape a model. This would only be appropriate if there was a realistic interface at the bottom layer of the model that would promote ponding and then water were to &amp;quot;punch through&amp;quot; that layer in the event the soil directly above the layer became saturated.&lt;/p&gt;&#xA;&lt;p&gt;A free draining boundary will assume the water can continue moving vertically at a unit gradient with the elements above. This assumption is good if the depth to a water table or some kind of low-permeability zone is quite a ways below a model area of interest.&lt;/p&gt;&#xA;&lt;p&gt;So - without knowing more about the particulars of your analysis, I'd expect a free draining boundary condition would be an ok starting point. Again, probably worth a sensitivity analysis when in doubt.&lt;/p&gt;&#xA;" OwnerUserId="5475" LastActivityDate="2022-12-09T05:54:09.010" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24605" PostTypeId="1" AcceptedAnswerId="24620" CreationDate="2022-12-09T18:29:43.247" Score="2" ViewCount="169" Body="&lt;p&gt;Suppose that at least 65m years ago, the dinosaurs (or, for that matter, another species) would have sufficiently developed to build settlements with houses, roads and the like.&lt;/p&gt;&#xA;&lt;p&gt;Would archaeologists be able to identify remains of these structures 65 million years later? Or would erosion, tectonic shifts and the like erase any possible traces? My idea is the following: One can argue on grounds like too small brains that dinosaurs did not have a 'civilization' and hence did not leave buildings. But can one argue against that on archaeological grounds?&lt;/p&gt;&#xA;" OwnerUserId="28110" LastEditorDisplayName="user27958" LastEditDate="2022-12-10T21:06:29.080" LastActivityDate="2022-12-12T10:11:38.067" Title="If dinosaurs lived in cities, would we be able to find traces?" Tags="|sedimentology|tectonics|stratigraphy|archaeology|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24606" PostTypeId="2" ParentId="24605" CreationDate="2022-12-10T10:32:08.017" Score="2" Body="&lt;p&gt;The register would have been mostly non-existent and there would be no inference of how the cities were or how the culture of the dinosaurs was, as even the cities had been buried by sediments quickly before erased by erosion, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Diagenesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;diagenesis&lt;/a&gt; would have destroyed the records later.&lt;/p&gt;&#xA;&lt;p&gt;The only cities that could have resisted should have been buried by a volcanic eruption and then not demolished by &lt;a href=&quot;https://en.wikipedia.org/wiki/Tectonics&quot; rel=&quot;nofollow noreferrer&quot;&gt;tectonics&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;If the cities had been as big as New York, detailed seismic profiles would show its trace in the cases the layers had evolved to be part of a &lt;a href=&quot;https://en.wikipedia.org/wiki/Sedimentary_basin&quot; rel=&quot;nofollow noreferrer&quot;&gt;sedimentary basin&lt;/a&gt; and the conditions wouldn't have evolved to &lt;a href=&quot;https://en.wikipedia.org/wiki/Metamorphism#Burial&quot; rel=&quot;nofollow noreferrer&quot;&gt;burial metamorphism&lt;/a&gt;; there are a lot of intact &lt;a href=&quot;https://en.wikipedia.org/wiki/Mesozoic&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mesozoic&lt;/a&gt; sedimentary basins in the Earth, even they are folded by &lt;a href=&quot;https://en.wikipedia.org/wiki/Orogeny&quot; rel=&quot;nofollow noreferrer&quot;&gt;orogeny&lt;/a&gt; pulses.&lt;/p&gt;&#xA;" OwnerDisplayName="user27958" LastEditorDisplayName="user27958" LastEditDate="2022-12-10T13:12:23.600" LastActivityDate="2022-12-10T13:12:23.600" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24607" PostTypeId="1" CreationDate="2022-12-10T10:40:16.920" Score="2" ViewCount="59" Body="&lt;p&gt;So far I understood, geopotential &lt;span class=&quot;math-container&quot;&gt;$\Phi$&lt;/span&gt; is just defined by&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\vec \nabla \phi = \vec g$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;But because g can be taken to be constant within troposphere, it is nothing but&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\Phi(z) = g \cdot z + C$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;So it is nothing more than height z multiplied by a constant. What is the benefit of it? These relations are trivial - is there anything I have overseen?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8B4B4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8B4B4.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;In this image one could equally say that minimum surface pressure corresponds to minimal &lt;strong&gt;height&lt;/strong&gt; of constant pressure layers above.&lt;/p&gt;&#xA;" OwnerUserId="21047" LastActivityDate="2022-12-10T10:40:16.920" Title="Why is the quantity &quot;Geopotential&quot; important in meteorology?" Tags="|meteorology|atmosphere-modelling|barometric-pressure|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24609" PostTypeId="1" CreationDate="2022-12-10T20:34:30.923" Score="4" ViewCount="316" Body="&lt;p&gt;To be exact, I'm talking about the Y-Axis. Normalizing does not make sense to me. How does this not skew data? &lt;a href=&quot;https://i.stack.imgur.com/ydhAt.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ydhAt.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28114" LastActivityDate="2023-01-09T21:06:15.720" Title="What is the point of normalizing rocks to chondrite or normalizing to anything else for that matter?" Tags="|models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24610" PostTypeId="1" AcceptedAnswerId="24616" CreationDate="2022-12-10T20:55:33.677" Score="3" ViewCount="163" Body="&lt;p&gt;Recently I was looking at a &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/c/cc/Earth_Impact_Database_world_map.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;map&lt;/a&gt; of known impact structures and I noticed that they are concentrated between the tropical and arctic latitudes, but there is very little near the equator.  I can think of a couple reasons that describe some features of the map, like how the Canadian Shield is ancient, has a lot of water, and lacks dense vegetation, which makes craters easy to spot.  Perhaps the crust near the equator is younger and just doesn't hold as long a record, but I am not a geologist so I'm just speculating.  It could also be that some physical argument like the conservation of angular momentum (i.e. which might cause a bias in trajectory deflections) and/or the distribution of asteroid orbits and their relative alignment with Earth's equatorial plane would be sufficient to explain this, but I'm curious if anyone knows of a better theory?&lt;/p&gt;&#xA;" OwnerUserId="26124" LastEditorUserId="26124" LastEditDate="2022-12-10T23:19:22.500" LastActivityDate="2022-12-24T00:57:03.203" Title="Distribution of terrestrial impact craters" Tags="|geology|geophysics|impact-craters|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24611" PostTypeId="2" ParentId="24609" CreationDate="2022-12-10T20:58:50.487" Score="2" Body="&lt;p&gt;It does skew (at least the visual representation of) the data. However, it skews it in a way that is consistent: if you compare the shape of the line or an individual normalized value across two normalized samples, you're still able to visually distinguish which sample is more enriched and by how much. Trace elements are much more variable across rocks than are major elements, so this is a powerful tool to visualize those trends and differences.&lt;/p&gt;&#xA;&lt;p&gt;Normalizing to chondrite is essentially asking: how does this rock's composition compare to bulk Earth? Is it evolved (i.e., is it enriched in incompatible elements)? If so, how much?&lt;/p&gt;&#xA;&lt;p&gt;Same idea for normalizing to depleted mantle, except now you're examining whether a magma is likely to have been derived from a 'typical' source (the upper/depleted mantle is the easiest/most common area that mantle-derived magmas are generated) or if you're dealing with a deeper or enriched source (lower undepleted mantle/metasomatized part of the mantle).&lt;/p&gt;&#xA;&lt;p&gt;Basically, it provides two major things: the ability to compare between samples, but also to obtain information about your samples' compositions relative to important compositional benchmarks.&lt;/p&gt;&#xA;" OwnerUserId="27389" LastActivityDate="2022-12-10T20:58:50.487" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24613" PostTypeId="2" ParentId="24585" CreationDate="2022-12-10T23:24:49.953" Score="0" Body="&lt;p&gt;The graph is showing the thermal emission from the Earth's surface. As you said, the atmosphere is optically thick at most infrared wavelengths. But eventually, if you go high enough, the atmosphere becomes optically thin. The atmosphere at that altitude emits infrared at wavelengths corresponding to its temperature.&lt;/p&gt;&#xA;&lt;p&gt;It's a little more complicated. Most of the infrared absorption is due to water vapor. If you were to look at the IR spectrum of water vapor, you'd see a forest of individual absorption lines. In between the lines, the altitude at which you reach optical depth equals 1 is lower, and in the core of a line it's at a much higher altitude. Since temperature changes with altitude, the spectrum gets quite complicated.&lt;/p&gt;&#xA;&lt;p&gt;When I was a grad student in astrophysics, we made observations from NASA-operated airplanes equipped with telescopes (specifically the Kuiper Airborne Observatory and the earlier, smaller Lear jet). We would fly around 40,000 feet, which was high enough at mid-latitudes to be in the stratosphere, but more importantly, it was above almost all the water vapor. Hence we were able to observe at wavelengths not accessible to ground-based observatories (in our case, 20-40 microns). During one of my oral exams, I was asked just this question - why 40,000 feet?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Electromagnetic_absorption_by_water&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Electromagnetic_absorption_by_water&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26208" LastActivityDate="2022-12-10T23:24:49.953" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24615" PostTypeId="1" CreationDate="2022-12-11T06:26:31.943" Score="6" ViewCount="623" Body="&lt;p&gt;I was always under the impression that evaporated water from the Atlantic Ocean traveled west to hydrate the eastern U.S. and that not only did the western U.S. have to deal with rain shadows from tall mountains, but the wind barely blew in that direction anyway.&lt;/p&gt;&#xA;&lt;p&gt;Apparently this isn't the case because the prevailing wind direction is almost always west to east. So where the heck is all the precipitation coming from? If it's coming from the west, why isn't it wetter westward than eastward?&lt;/p&gt;&#xA;" OwnerUserId="17412" LastActivityDate="2022-12-11T16:24:24.387" Title="Why is the eastern United States green if the wind moves from west to east?" Tags="|meteorology|rainfall|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24616" PostTypeId="2" ParentId="24610" CreationDate="2022-12-11T09:28:19.887" Score="2" Body="&lt;p&gt;One thing to consider is, currently, there is very little above ocean land mass around the equator. The bulk of the land mass lies above the tropic of Cancer in the northern hemisphere.&lt;/p&gt;&#xA;&lt;p&gt;The other thing to consider is plate tectonics. Apart from Antarctica, most of the land masses have moved over time, spending various amounts of time at various latitudes and the craters that do exist may not have been created where the land masses are currently located, they may been created when the land mass was elsewhere. With plate tectonics there is also the matter of crustal renewal &amp;amp; recycling.&lt;/p&gt;&#xA;&lt;p&gt;Regarding the Sahara and Namib desserts there may be craters covered by deep sand.&lt;/p&gt;&#xA;&lt;p&gt;The map you link to in your question is a very interesting map. It would be even more interesting to have a similar series of maps for the different geological ages of Earth with the craters created on each land mass during each of those ages to see where the land masses were when they were hit.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-12-11T09:28:19.887" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24617" PostTypeId="2" ParentId="24615" CreationDate="2022-12-11T16:14:54.167" Score="8" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Why is the eastern United States green if the wind moves from west to east?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The winds don't move straight from west to east. Oftentimes they move from the southwest to the northeast (and sometimes from the south to the north), thereby bringing lots of moisture inland from the very warm Gulf of Mexico. If you want to see green in the continental US, you could go to western Washington. Or, you can drive along the US Gulf Coast from Brazosport, Texas to Tallahassee, Florida; rainfall exceeds 50 inches per year all along the route, in some places well over 60 inches per year. The Gulf moisture moves all the way from the Gulf to Canada, eventually dropping from the sky as rain.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="543" LastEditDate="2022-12-11T16:24:24.387" LastActivityDate="2022-12-11T16:24:24.387" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24619" PostTypeId="1" CreationDate="2022-12-12T06:13:11.103" Score="3" ViewCount="41" Body="&lt;p&gt;In Ocean spectrum modelling there are different modelling procedures are available such as Fung Lee model, JONSWAP model, Elfouhaily model, WWIII model and SWAN model. Among those models based on which parameter we can say this model is comparatively better than another one?&lt;/p&gt;&#xA;" OwnerUserId="28085" LastEditorUserId="28085" LastEditDate="2022-12-12T10:50:31.143" LastActivityDate="2022-12-12T10:50:31.143" Title="Validation parameter of spectrum model" Tags="|waves|wave-modeling|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24620" PostTypeId="2" ParentId="24605" CreationDate="2022-12-12T09:29:30.203" Score="3" Body="&lt;p&gt;&amp;quot;Lack of evidence is not evidence of lack.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;That said, there is no evidence of any intelligent civilization prior to humanity. If dinosaurs, or for that matter, some other species, had achieved our current human level of civilization, only to be wiped out by an asteroid collision with the Earth, there would be evidence that that high level civilization had happened. We wouldn't see the huge deposits of coal and oil dating back to the Carboniferous and the huge deposits of iron dating back to the two billion year old oxygenating of the atmosphere, all of  which we are currently exploiting. We would see strange bands of iron embedded in very thin and narrow but very long rock formations (i.e., 65 million year old freeways). We don't see any of that. A dinosaur equivalent of our current level civilization can be ruled out.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, if dinosaurs or some other species had only achieved the equivalent of pre-pottery Neolithic civilization when the first towns were being built by humans (about 10000 years ago), only to be wiped out by an asteroid collision with the Earth, there might well be no evidence of that. It has been hard enough for archeologists to find the rather faint signs of those 10000 year old civilizations, and that's mostly because those archeologists know where to look. Finding signs of an equivalent 65 million year old civilization where no one knows where to look would be nigh impossible. Lack of evidence is not evidence of lack.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-12-12T09:29:30.203" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24621" PostTypeId="2" ParentId="24605" CreationDate="2022-12-12T10:11:38.067" Score="1" Body="&lt;p&gt;We found many dinosaur &lt;a href=&quot;https://en.wikipedia.org/wiki/Fossil_track&quot; rel=&quot;nofollow noreferrer&quot;&gt;fossil tracks&lt;/a&gt; around the world, and they all have one thing in common: they are tracks of bare feet.&lt;/p&gt;&#xA;&lt;p&gt;We invented shoes about &lt;a href=&quot;https://en.wikipedia.org/wiki/Shoe#History&quot; rel=&quot;nofollow noreferrer&quot;&gt;10,000 years ago&lt;/a&gt;, a few millennia before building cities.&lt;/p&gt;&#xA;&lt;p&gt;So, if the dinosaurs had developed enough to build cities, they definitely would have worn shoes and we would see these shoes in fossil tracks.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2022-12-12T10:11:38.067" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24622" PostTypeId="1" CreationDate="2022-12-12T13:06:46.240" Score="2" ViewCount="179" Body="&lt;p&gt;In the winter when it's overcast, clouds at night are much brighter or more easily illuminated (unsure if they appear above cities/towns only) than in summer, making them look orange at night. I don't remember ever having seen nights with such clouds in the summer, I only know them from the winter. Why are those clouds so bright/orange only during the winter? Aren't they the same clouds it rains from in the summer?&lt;/p&gt;&#xA;" OwnerUserId="28130" LastEditorUserId="28130" LastEditDate="2022-12-12T13:08:31.610" LastActivityDate="2022-12-12T13:08:31.610" Title="Why are nocturnal winter clouds so bright or so easily illuminated at night, compared to clouds in the summer?" Tags="|meteorology|clouds|winter|" AnswerCount="0" CommentCount="20" ContentLicense="CC BY-SA 4.0" />
  <row Id="24623" PostTypeId="1" AcceptedAnswerId="24632" CreationDate="2022-12-12T21:49:29.017" Score="6" ViewCount="489" Body="&lt;p&gt;Why does Earth's atmosphere have a whiter color (paler) near the horizon? (on a clear, cloudless day when the sun is highest in the sky)?&lt;/p&gt;&#xA;&lt;p&gt;The amount of air being greater in this direction, why is the atmosphere near the horizon whiter (paler) instead of red, orange like at sunset and sunrise?&lt;/p&gt;&#xA;" OwnerUserId="28134" LastEditorUserId="28134" LastEditDate="2022-12-13T14:59:16.320" LastActivityDate="2023-04-01T15:22:17.297" Title="Why does Earth's atmosphere have a whiter color near the horizon?" Tags="|meteorology|atmosphere|clouds|earth-observation|atmospheric-optics|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24624" PostTypeId="2" ParentId="24235" CreationDate="2022-12-13T11:21:51.347" Score="2" Body="&lt;p&gt;&lt;strong&gt;These GFS parameters are stored as a running average, reset every 6 hours.&lt;/strong&gt; This is a bit unusual and requires some special handling to get back to hourly forecasts.&lt;/p&gt;&#xA;&lt;p&gt;The value you have, time-tagged 03:00 (3h) and labeled as &amp;quot;0-3 hour ave&amp;quot; in GRIB is indeed the average of the forecasts from 0-3 hours ahead, time-tagged interval ending. Or could be understood as the average of what one would typically like to have as three one-hour averages labelled 01:00 (0-1 hour ahead average), 02:00 (1-2 hour ahead average) and 03:00 (2-3 hour ahead average), time-tagged interval ending.&lt;/p&gt;&#xA;&lt;p&gt;This is as follows for each the different time steps found in GFS data:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;01:00 (labeled as &amp;quot;0-1 hour ave&amp;quot;): the forecast for 01:00 (tagged interval ending, 1 hour average).&lt;/li&gt;&#xA;&lt;li&gt;02:00 (labeled as &amp;quot;0-2 hour ave&amp;quot;): the average of the 01:00 and 02:00 forecasts (interval ending 1 hour averages).&lt;/li&gt;&#xA;&lt;li&gt;03:00 (labeled as &amp;quot;0-3 hour ave&amp;quot;): the average of the 01:00, 02:00, 03:00 forecasts.&lt;/li&gt;&#xA;&lt;li&gt;04:00 (labeled as &amp;quot;0-4 hour ave&amp;quot;): the average of the 01:00, 02:00, 03:00, 04:00 forecasts.&lt;/li&gt;&#xA;&lt;li&gt;05:00 (labeled as &amp;quot;0-5 hour ave&amp;quot;): the average of the 01:00, 02:00, 03:00, 04:00, 05:00 forecasts.&lt;/li&gt;&#xA;&lt;li&gt;06:00 (labeled as &amp;quot;0-6 hour ave&amp;quot;): the average of the 01:00, 02:00, 03:00, 04:00, 05:00, 06:00 forecasts.&lt;/li&gt;&#xA;&lt;li&gt;07:00 (labeled as &amp;quot;6-7 hour ave&amp;quot;): the 07:00 forecast. The averaging has been reset after 6h.&lt;/li&gt;&#xA;&lt;li&gt;08:00 (labeled as &amp;quot;6-8 hour ave&amp;quot;): the average of the 07:00 and 08:00 forecasts.&lt;/li&gt;&#xA;&lt;li&gt;and so on.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;To &lt;strong&gt;get back to hourly forecasts&lt;/strong&gt; (or 3-hourly for 3-hourly datasets), you either need to do the math yourself or you can use the &lt;code&gt;wgrib2&lt;/code&gt; option &lt;code&gt;-ncep_norm&lt;/code&gt;. See &lt;a href=&quot;https://www.cpc.ncep.noaa.gov/products/wesley/wgrib2/ncep_norm.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.cpc.ncep.noaa.gov/products/wesley/wgrib2/ncep_norm.html&lt;/a&gt; .&lt;/p&gt;&#xA;&lt;p&gt;To &lt;strong&gt;convert back yourself&lt;/strong&gt;, you need to use the previous average and substract it with proper weighting. Here is short instructions by Shrinivas Moorthi from this thread &lt;a href=&quot;http://gradsusr.org/pipermail/gradsusr/2016-November/040397.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://gradsusr.org/pipermail/gradsusr/2016-November/040397.html&lt;/a&gt; :&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;Let us denote the data from 6 hourly output as C1, C2, C3, C4, C5, C6.&#xA;&#xA;To get hourly mean, then&#xA;for hour 1, the mean is C1,&#xA;for hour 2, the mean is 2C2-C1&#xA;for hour 3, the mean is 3C3-2C2&#xA;for hour 4, the mean is 4C4-3C2&#xA;for hour 5, the mean is 5C5-4C4&#xA;and for hour 6, it is 6C6-5C5&#xA;&#xA;This pattern repeats every six ours.&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;There also is an NCEP/NOAA paper on the model data, where this is explained somewhere deep down, but I couldn't find it right now. The two links above however give a bit of explanation/guidance as well.&lt;/p&gt;&#xA;&lt;p&gt;And always a good idea to compare your results to the output of a tool doing the conversion automatically.&lt;/p&gt;&#xA;" OwnerUserId="28138" LastEditorUserId="28138" LastEditDate="2022-12-13T11:41:08.357" LastActivityDate="2022-12-13T11:41:08.357" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24625" PostTypeId="1" CreationDate="2022-12-13T13:16:34.180" Score="2" ViewCount="123" Body="&lt;p&gt;Comming from this question:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/246/can-we-really-travel-through-earths-core&quot;&gt;Can we really travel through earth's core?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I wonder what makes special a &lt;a href=&quot;https://en.wikipedia.org/wiki/Volcanic_pipe&quot; rel=&quot;nofollow noreferrer&quot;&gt;volcanic pipe&lt;/a&gt; to be stable since the mantle through the surface, in comparison to &lt;a href=&quot;https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole&quot; rel=&quot;nofollow noreferrer&quot;&gt;our try&lt;/a&gt; or expectatives to drill a superhole.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sIXWR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sIXWR.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;Souce of the image: &lt;a href=&quot;https://www.bgs.ac.uk/discovering-geology/earth-hazards/volcanoes/how-volcanoes-form/&quot; rel=&quot;nofollow noreferrer&quot;&gt;British Geological Survey&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;What's the physics behind this nature success?&lt;/p&gt;&#xA;" OwnerDisplayName="user27958" LastEditorDisplayName="user27958" LastEditDate="2022-12-13T18:39:45.277" LastActivityDate="2022-12-13T18:39:45.277" Title="What makes special a volcanic pipe to be stable until the mantle?" Tags="|geophysics|volcanology|mantle|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24626" PostTypeId="1" AcceptedAnswerId="24627" CreationDate="2022-12-13T16:40:24.940" Score="3" ViewCount="126" Body="&lt;p&gt;I traversed a route in a city. The route has different elevation. So I need to remove the effect of elevation from my air temperature measurements. The measurements done by temperature data logger mounted over a car and a GPS in it. So, the air temperature joined to location which has elevation. As result, I have air temperature and elevation fields loaded up into Excel.&lt;/p&gt;&#xA;&lt;p&gt;All I need to do it to correct the effect of elevation on my air temperature data, which I do not know how to do that.&lt;/p&gt;&#xA;" OwnerUserId="28140" LastActivityDate="2022-12-14T00:46:48.583" Title="How to remove effect of topography on Air temperature in Excel?" Tags="|temperature|topography|air|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24627" PostTypeId="2" ParentId="24626" CreationDate="2022-12-14T00:46:48.583" Score="2" Body="&lt;p&gt;Definitely an interesting question...  You need to adjust your temperature data to a common elevation by using the lapse rate.  The lapse rate can be determined as the temperature change over a standard interval in elevation change.  For instance, find the lowest elevation on your traveled route, and note the temperature.  Then for each location for which you have both elevation and temperature, determine the elevation difference and temperature difference to that lowest elevation location.  The lapse rate will be derived as the temperature difference per unit elevation difference.  In other words, the lapse rate will be noted as so many degrees per 100 meters change in elevation.  The lapse rate determined for the locations on your traversed route can be averaged and your data reduced to a common elevation on the basis of the average lapse rate.  My assumption is that the determined lapse rates would likely be relatively close in value when expressed as a temperature change for given standard elevation change.&lt;/p&gt;&#xA;&lt;p&gt;Now, with the lapse rate known, your temperature data can be reduced to a common elevation.  Nevertheless, a consideration would be if you noticed that the lapse rate was considerably different from location to location.  Consequently, you may wish to simply adjust each location to a common elevation by using the lapse rate derived for that location based on a comparison with that location's nearest neighbor.  You can derive the local lapse rate by comparison of nearby locations, and then reduce your various measurements to a common elevation for comparison.&lt;/p&gt;&#xA;&lt;p&gt;Lapse rate is typically a feature of an airmass.  The lapse rate is dependent on water vapor content in the air.  Commonly, the lapse rate is taken as a specific value for dry air, or for moist air.  You can compare the lapse rate you have derived with these values to get a sense of whether the air is moist or dry.  Consequently, you can determine if the lapse rate is related to the region or area for which your temperature measurements were made.  For instance, near the coast the lapse rate may be lower due to moisture in the air.  Farther inland, in dryer air, the lapse rate may be higher due to less moisture in the air.&lt;/p&gt;&#xA;&lt;p&gt;An interesting question. Thanks for asking.&lt;/p&gt;&#xA;" OwnerUserId="28142" LastActivityDate="2022-12-14T00:46:48.583" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24628" PostTypeId="1" AcceptedAnswerId="24629" CreationDate="2022-12-14T07:21:51.060" Score="7" ViewCount="1146" Body="&lt;p&gt;At 2735 m (8973 ft) below sea level, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Kidd_Mine&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kidd mine&lt;/a&gt; reportedly has the deepest non-marine point of the Earth's surface (since the Kola borehole is sealed). I wonder what the pressure down there is, as compared to 14.696 psi (1013.25 hPa) at sea level and 15.45 psi (1065 hPa) on the shore of the Dead Sea (413 m = 1355 ft below sea level standard).&lt;/p&gt;&#xA;" OwnerUserId="28130" LastEditorUserId="6298" LastEditDate="2022-12-17T07:06:27.990" LastActivityDate="2022-12-17T07:06:27.990" Title="What is the atmospheric pressure at the deepest point of the Kidd mine?" Tags="|atmosphere-modelling|mining|barometric-pressure|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24629" PostTypeId="2" ParentId="24628" CreationDate="2022-12-14T11:31:27.470" Score="6" Body="&lt;p&gt;From the book &lt;em&gt;Environmental Engineering in South African Mines&lt;/em&gt;, The Mine Ventilation Society of South Africa, 1989, pp 451-455.&lt;/p&gt;&#xA;&lt;p&gt;The equation required is:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$P \ = \ P_{atm}\cdot e^{\frac{-gMh}{1000R\cdot (273.15+t_{dry})}}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$P_{atm}$&lt;/span&gt; = Atmospheric air pressure&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$t_{dry}$&lt;/span&gt; = Dry bulb temperature&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; = acceleration due to gravity, 9.8 m/s&lt;sup&gt;2&lt;/sup&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$M$&lt;/span&gt; = Molar mass of air on Earth, 28.9644 g/mol&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$h$&lt;/span&gt; = The difference in elevation, -2735 m&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; = The universal gas constant, 8.3144622 J/mol&lt;span class=&quot;math-container&quot;&gt;$\cdot$&lt;/span&gt;K&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Current data is being taken from the Canadian government weather service website. The nearest town to Kidd Creek is &lt;a href=&quot;https://weather.gc.ca/city/pages/on-127_metric_e.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Timmins, Ontario&lt;/a&gt;, approximately 25 km south.&lt;/p&gt;&#xA;&lt;p&gt;For 14 December 2022, the dry bulb temperature on the surface is -12.6 °C and the &lt;em&gt;sea level adjusted&lt;/em&gt; atmospheric pressure is 1032 hPa (103 200 Pa). Given the depth of the mine and heating of the air due to both auto compression, the geothermal gradient and any diesel powered equipment in the mine, the temperature of the air at the bottom of the exhaust ventilation shaft will most likely be around 30 °C.&lt;/p&gt;&#xA;&lt;p&gt;The atmospheric pressure at a depth of 2735 m is,&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$P \ = \ 103\ 200\cdot e^{\frac{-9.8(28.9644)(-2735)}{1000(8.31446) (273.15+30)}}$&lt;/span&gt; = &lt;span class=&quot;math-container&quot;&gt;$140\ 400\ Pa = 1404\ hPa = 20.37 \ psi$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="6298" LastEditDate="2022-12-17T07:01:42.240" LastActivityDate="2022-12-17T07:01:42.240" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24630" PostTypeId="5" CreationDate="2022-12-14T19:10:35.003" Score="0" Body="" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2022-12-14T19:10:35.003" LastActivityDate="2022-12-14T19:10:35.003" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24631" PostTypeId="4" CreationDate="2022-12-14T19:10:35.003" Score="0" Body="For question dealing with the Earth's crust or other planemos." OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2022-12-14T19:10:35.003" LastActivityDate="2022-12-14T19:10:35.003" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24632" PostTypeId="2" ParentId="24623" CreationDate="2022-12-14T20:23:31.760" Score="8" Body="&lt;p&gt;The reason is that the horizon is paler is that we are seeing all wavelengths of sunlight equally scattered into our eye from along the line-of-sight to (and beyond) the horizon, so the horizon appears to be the same color as sunlight, i.e. &lt;a href=&quot;https://www.spacecentre.nz/resources/faq/solar-system/sun/colour.html&quot; rel=&quot;noreferrer&quot;&gt;white&lt;/a&gt;.&#xA;This is because for far enough distances, the higher probability of short wavelength (&amp;quot;blue&amp;quot;) light scattering in our direction from distant air is cancelled out by the same scattering processes causing the light to be attenuated as it travels through the air to your eye.&lt;/p&gt;&#xA;&lt;p&gt;This explanation is essentially the same as given on page 269 of M.G.J. Minnaert's &lt;a href=&quot;https://archive.org/details/lightcolorinoutd0000minn/page/269/mode/1up&quot; rel=&quot;noreferrer&quot;&gt;&amp;quot;Light and Color in the Outdoors&amp;quot;&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;If we are looking towards the horizon, what we see is sunlight scattered from the air along our line-of-sight.  For simplicity, let's assume a constant density uniform atmosphere along that line of sight, which isn't a terrible approximation since the line-of-sight is close to the earth's surface until it passes well beyond the horizon. The amount of sunlight scattered from a small section &lt;span class=&quot;math-container&quot;&gt;$dx$&lt;/span&gt; along that line-of-sight is proportional to &lt;span class=&quot;math-container&quot;&gt;$dx/\mu$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$\mu$&lt;/span&gt; is the scattering length in air. If the section is a distance &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt; away from us along that line-of-sight, the fraction of that scattered light that will reach our eye will be &lt;span class=&quot;math-container&quot;&gt;$e^{-x/\mu}$&lt;/span&gt;.&#xA;The total amount of light we will see scattered back to us from from along that line of sight will be proportional to&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\int_0^D e^{-x/\mu} \frac{dx}{\mu}=1-e^{-D/\mu} \xrightarrow[D&amp;gt;&amp;gt;\mu]{}1$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$D$&lt;/span&gt; is the distance to the farthest scattered light we can see.&#xA;(I first thought there should be a &lt;span class=&quot;math-container&quot;&gt;$1/x^2$&lt;/span&gt; factor as the light source gets farther away, but this is cancelled out because for a fixed viewing solid angle, the observed source volume increases as &lt;span class=&quot;math-container&quot;&gt;$x^2$&lt;/span&gt;.)&lt;/p&gt;&#xA;&lt;p&gt;As long as &lt;span class=&quot;math-container&quot;&gt;$D&amp;gt;\mu({\lambda})$&lt;/span&gt; for all visible wavelengths, if the scattering probability for a given wavelength is larger, more of that wavelength is scattered from the element &lt;span class=&quot;math-container&quot;&gt;$dx$&lt;/span&gt;, but also more is scattered away along its path to you, and the two effects cancel out. The wavelength dependence of the scattering drops out of the integral and what is see is the colour of the initial sunlight.&lt;/p&gt;&#xA;&lt;p&gt;Assuming the atmosphere ends at the earth's atmospheric &lt;a href=&quot;https://en.wikipedia.org/wiki/Scale_height&quot; rel=&quot;noreferrer&quot;&gt;scale height&lt;/a&gt; of &lt;span class=&quot;math-container&quot;&gt;$\sim 8.5$&lt;/span&gt; km, the assumption of &lt;span class=&quot;math-container&quot;&gt;$D&amp;gt;\mu$&lt;/span&gt; seems reasonable since on a perfectly clear day our line-of-sight in air &lt;a href=&quot;http://www.ringbell.co.uk/info/hdist.htm&quot; rel=&quot;noreferrer&quot;&gt;extends over 300 kilometres&lt;/a&gt; beyond the horizon.  This is longer than the &lt;a href=&quot;https://en.wikipedia.org/wiki/Rayleigh_scattering#Small_size_parameter_approximation&quot; rel=&quot;noreferrer&quot;&gt;Rayleigh scattering length for green light&lt;/a&gt; (&lt;span class=&quot;math-container&quot;&gt;$532$&lt;/span&gt; nm) of about &lt;span class=&quot;math-container&quot;&gt;$100$&lt;/span&gt; km.&#xA;The actual scattering lengths will usually even be shorter because of significant &lt;a href=&quot;https://en.wikipedia.org/wiki/Mie_scattering&quot; rel=&quot;noreferrer&quot;&gt;Mie scattering&lt;/a&gt; from aerosols such as water droplets and dust between us and the horizon.&#xA;Even if the distances are not enough to make the horizon pure white, it will still be much paler than the blue sky overhead.&#xA;(The reason the sky overhead looks blue is because there isn't enough distance (i.e. &lt;span class=&quot;math-container&quot;&gt;$D_{sky} \lesssim 8.5\,\textrm{km}&amp;lt;\mu(\lambda)$&lt;/span&gt;) for the scattering along the line-of-sight to cancel out the larger initial scattering of blue light.)&lt;/p&gt;&#xA;" OwnerUserId="27775" LastActivityDate="2022-12-14T20:23:31.760" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24633" PostTypeId="2" ParentId="24580" CreationDate="2022-12-15T08:24:15.380" Score="2" Body="&lt;p&gt;I think the ERA5-Land dataset suits your purpose. See &lt;a href=&quot;https://www.ecmwf.int/en/era5-land&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ecmwf.int/en/era5-land&lt;/a&gt;. As the website says, &lt;em&gt;'The data is a replay of the land component of the ERA5 climate reanalysis with a finer spatial resolution: ~9km grid spacing.'&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="15226" LastActivityDate="2022-12-15T08:24:15.380" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24634" PostTypeId="1" CreationDate="2022-12-15T14:04:43.130" Score="4" ViewCount="114" Body="&lt;p&gt;I plan to study a good introductory book on atmospheric dynamics:&#xA;which one is more recommended? My background is a university degree in physics, but I'm new to meteorology.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;An Introduction to&#xA;Dynamic Meteorology&#xA;James R. Holton&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Fluid Dynamics of the&#xA;Midlatitude Atmosphere&#xA;Brian J. Hoskins&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Mid-Latitude Atmospheric&#xA;Dynamics, A First Course&#xA;Jonathan E. Martin&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="21047" LastActivityDate="2022-12-15T14:04:43.130" Title="Book on atmosphere dynamics" Tags="|meteorology|atmosphere|atmosphere-modelling|atmospheric-circulation|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24635" PostTypeId="1" AcceptedAnswerId="24641" CreationDate="2022-12-16T13:14:27.410" Score="2" ViewCount="170" Body="&lt;p&gt;I wonder whether there's a way of learning how much of the Earth's surface is above or below a certain altitude (land on air only, i.e. excluding seas and oceans and land underwater).&lt;/p&gt;&#xA;&lt;p&gt;E.g. the lowest/deepest point of the Earth's surface on land is the shore of the Dead Sea at 1355 ft below sea level standard. So above 1356 ft (413.3 m) below sea level 100% of the Earth's surface there are. The highest point of the Earth's surface is the summit of Mt Everest so 100% of the Earth's surface are within 29,032 ft (8849 m) above sea level. Now if I wanted to know how much of the Earth's surface is within say 10,000 ft (3048 m) above sea level, is there a good way to find out?&lt;/p&gt;&#xA;" OwnerUserId="28130" LastActivityDate="2022-12-18T21:41:27.953" Title="How or where to find out how many percent of the Earth's surface is above/below a certain altitude?" Tags="|land-surface|mathematics|altitude|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24636" PostTypeId="1" CreationDate="2022-12-16T14:01:33.027" Score="3" ViewCount="54" Body="&lt;p&gt;I'm doing some research and I'm in need of some well-log data from a sonic tool. I'm specifically looking for a multi-receiver tool with 6 or more receivers if possible.&lt;/p&gt;&#xA;&lt;p&gt;I've been able to find a lot of 2D/3D seismic data such as SEG data pool but well-log data seems in very short supply.&lt;/p&gt;&#xA;" OwnerUserId="28154" LastActivityDate="2023-01-24T13:26:37.200" Title="Where can I access public sonic well-log data?" Tags="|geology|geophysics|seismology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24638" PostTypeId="1" AcceptedAnswerId="24657" CreationDate="2022-12-17T11:25:24.830" Score="2" ViewCount="53" Body="&lt;p&gt;Currently I hear a series of tutorial videos on atmospheric dynamics as a first starting preparation for reading more detailed material, such as Holton. In particular I refer to this part:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=YjugCNkLD0k&amp;amp;list=PL_cuIb7hx5lg_zHfUVsUrw6I66U4jq8Dq&amp;amp;index=10&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=YjugCNkLD0k&amp;amp;list=PL_cuIb7hx5lg_zHfUVsUrw6I66U4jq8Dq&amp;amp;index=10&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4VYH3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4VYH3.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I can follow more or less the derivation of what we see here, namely that by using p instead of z for the vertical coordinate the pressure force on an air parcel reduces to gradient of geopotential &lt;span class=&quot;math-container&quot;&gt;$\Phi$&lt;/span&gt;:&lt;/p&gt;&#xA;&lt;p&gt;Still I have some troubles with regard to the mathematical formalism:&lt;/p&gt;&#xA;&lt;p&gt;What does &lt;span class=&quot;math-container&quot;&gt;$\left(\frac{\partial \Phi}{\partial x}\right)_p$&lt;/span&gt; mean mathematically? I would have assumed, that &lt;span class=&quot;math-container&quot;&gt;$\Phi$&lt;/span&gt; is a function of &lt;span class=&quot;math-container&quot;&gt;$x, y, p$&lt;/span&gt;: &lt;span class=&quot;math-container&quot;&gt;$\Phi = \Phi(x,y,p)$&lt;/span&gt; and, therefore &lt;span class=&quot;math-container&quot;&gt;$\frac{\partial \Phi}{\partial x}$&lt;/span&gt; means to keep y,p as constant and consider only the change of &lt;span class=&quot;math-container&quot;&gt;$\Phi$&lt;/span&gt; caused by a change in x (this is the definition of partial derivative). Why do we write &lt;span class=&quot;math-container&quot;&gt;$\left(\frac{\partial \Phi}{\partial x}\right)_p$&lt;/span&gt; instead? Once we agree on a special set of coordinates we dont have to specify what other coordinates are held constant for the partial derivative. But if we decide to do it, why is it then not written as &lt;span class=&quot;math-container&quot;&gt;$\left(\frac{\partial \Phi}{\partial x}\right)_{y,p}$&lt;/span&gt; ? Looks a bit confusing.&lt;/p&gt;&#xA;&lt;p&gt;Because of this notational discrepancy, I'm afraid I haven't quite gotten the &amp;quot;magic behind it&amp;quot; yet, maybe missing the most important point of all, and therefore just think I got it.&lt;/p&gt;&#xA;&lt;p&gt;Can somebody explain, where I have my missing point?&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2022-12-17T14:53:33.477" LastActivityDate="2022-12-20T20:54:19.940" Title="What does the index &quot;p&quot; mean in the gradient of geopotential in pressure coordinates?" Tags="|meteorology|atmosphere|atmosphere-modelling|barometric-pressure|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24639" PostTypeId="1" CreationDate="2022-12-17T18:29:08.883" Score="2" ViewCount="20" Body="&lt;p&gt;I just learned that the &lt;a href=&quot;https://www.wikiwand.com/en/Eoarchean&quot; rel=&quot;nofollow noreferrer&quot;&gt;eoarchean era&lt;/a&gt; comes right before the &lt;a href=&quot;https://www.wikiwand.com/en/Paleoarchean&quot; rel=&quot;nofollow noreferrer&quot;&gt;paleoarchean era&lt;/a&gt;, whereas the &lt;a href=&quot;https://www.wikiwand.com/en/Paleocene&quot; rel=&quot;nofollow noreferrer&quot;&gt;paleocene epoch&lt;/a&gt; comes right before the &lt;a href=&quot;https://www.wikiwand.com/en/Eocene&quot; rel=&quot;nofollow noreferrer&quot;&gt;eocene epoch&lt;/a&gt;. This is quite confusing. Is there any sense behind this (seemingly inconsistent) terminology, or is it just due to historical accidents?&lt;/p&gt;&#xA;" OwnerUserId="17342" LastEditorUserId="17342" LastEditDate="2022-12-17T18:47:26.437" LastActivityDate="2022-12-17T18:47:26.437" Title="Why the reversed-order terminology for paleocene/eocene and eoarchean/paleoarchean?" Tags="|earth-history|terminology|time|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24640" PostTypeId="1" CreationDate="2022-12-17T21:50:35.900" Score="3" ViewCount="132" Body="&lt;p&gt;What is the current ratio of the amount of water in the Earth's atmosphere compared to its moisture storage capacity?&lt;/p&gt;&#xA;&lt;p&gt;I see values like &amp;quot;a half&amp;quot; or &amp;quot;70% on various web pages, but can't find an actual source.  I can find good sources for trends and annual variations in the humidity, but they only give the percentage changes, such as these &lt;a href=&quot;https://climate.metoffice.cloud/humidity.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;UK Met Office trends&lt;/a&gt;.  The total water content of the atmosphere is also given in lots of places as &lt;a href=&quot;https://www.usgs.gov/special-topics/water-science-school/science/atmosphere-and-water-cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;12,900 cubic kilometres&lt;/a&gt;, but I haven't found a corresponding water storage capacity integrated over the whole atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="27775" LastActivityDate="2022-12-17T21:50:35.900" Title="What is the &quot;average relative humidity&quot; of the Earth's atmosphere?" Tags="|atmosphere|humidity|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24641" PostTypeId="2" ParentId="24635" CreationDate="2022-12-18T21:41:27.953" Score="2" Body="&lt;p&gt;What you want is known as a hypsograph or a &lt;a href=&quot;https://www.britannica.com/science/hypsometric-curve&quot; rel=&quot;nofollow noreferrer&quot;&gt;hypsographic/hypsometric curve&lt;/a&gt; which shows the distribution of elevations of the Earth's land surfaces (and can be extended to include the distribution of depths in the oceans). You can find such curves on the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hypsometry&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia Hypsometry&lt;/a&gt; page.&lt;/p&gt;&#xA;&lt;p&gt;Interesting higher resolution versions for each of the Earth, Moon, Mars, and Venus are shown in &lt;a href=&quot;https://www.earth.northwestern.edu/individ/donna/venustopo11.pdf&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;Paul R. Stoddard and Donna M. Jurdy, Icarus 217 (2012) 524-533&quot;&gt;&amp;quot;Topographic comparisons of uplift features on Venus and Earth: Implications for Venus tectonics&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;If you want to create your own hypsograph for the Earth with higher resolution, you can download the data from the &lt;a href=&quot;https://www.ncei.noaa.gov/products/etopo-global-relief-model&quot; rel=&quot;nofollow noreferrer&quot;&gt;ETOPO Global Relief Model&lt;/a&gt;. You'll need to read the &lt;a href=&quot;https://www.ngdc.noaa.gov/mgg/global/relief/ETOPO2022/docs/1.2%20ETOPO%202022%20User%20Guide.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;ETOPO 2022 User Guide&lt;/a&gt; and get the appropriate software to extract the &lt;a href=&quot;https://en.wikipedia.org/wiki/GeoTIFF&quot; rel=&quot;nofollow noreferrer&quot;&gt;GeoTIFF&lt;/a&gt; formatted data. Appropriate libraries exist for &lt;a href=&quot;https://rasterio.readthedocs.io/en/latest/quickstart.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Python&lt;/a&gt; and other languages. &lt;a href=&quot;https://gis.stackexchange.com&quot;&gt;GIS Stackexchange&lt;/a&gt; is a good place to ask questions about &lt;a href=&quot;https://gis.stackexchange.com/search?q=hypsometric&quot;&gt;hypsometric curves&lt;/a&gt; or &lt;a href=&quot;https://gis.stackexchange.com/search?q=geoTIFF&quot;&gt;geoTIFF&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="27775" LastActivityDate="2022-12-18T21:41:27.953" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24642" PostTypeId="1" CreationDate="2022-12-19T09:10:23.607" Score="3" ViewCount="46" Body="&lt;p&gt;When a saturated rock sample is rapidly extracted from a place with high water pressure, as happens in oil drilling or deep mining, the water is trapped inside the rock at high pressure, trying to escape.&lt;/p&gt;&#xA;&lt;p&gt;Does it makes the rock brittle or easy to carve? Does the rock break between crystals, or the crystal themselves become softer/brittle?&lt;/p&gt;&#xA;&lt;p&gt;I'm interested in hard rocks like granite or basalt, not sedimentary rocks.&lt;/p&gt;&#xA;&lt;p&gt;Where can I read about it? I searched, but I do not know the terminology, so I found nothing.&lt;/p&gt;&#xA;" OwnerUserId="28164" LastEditorUserId="2470" LastEditDate="2022-12-21T01:56:49.837" LastActivityDate="2022-12-21T01:56:49.837" Title="Are rocks extracted from deep drilling, brittle due to pore pressure?" Tags="|water|rocks|pressure|drilling|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24643" PostTypeId="1" AcceptedAnswerId="24645" CreationDate="2022-12-19T11:41:18.880" Score="2" ViewCount="57" Body="&lt;p&gt;Equation for acceleration of an air parcel is&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$D \vec U/Dt = -2 \vec \omega \times \vec U -\frac{1}{\rho} \vec \nabla p + \vec g$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now, for geostrophic wind, U is parallel to the contour lines of constant p.&lt;/p&gt;&#xA;&lt;p&gt;But if this is the case, then all forces above (beside g) are perpendicular to U. So how can U change when the lines of constant pressure get closer: in this case velocity should rise because larger gradient of p. In the moment I regard this as a discrepancy. How to resolve it?&lt;/p&gt;&#xA;&lt;p&gt;EDIT:&lt;/p&gt;&#xA;&lt;p&gt;This is what I mean in a picture:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aSFgP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aSFgP.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As the the blue air parcel moves from left to right on a line of constant pressure it becomes slower (red arrow), although the local change of speed is zero (stationary flow). It means, there must be a force on it which directs along its direction of flow (in fact its energy is decreased, because it is slower). The question is: where is this force coming from, since both pressure force and Coriolis force are perpendicular to the parcel's speed in each moment.&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2022-12-19T15:40:01.740" LastActivityDate="2022-12-19T15:40:01.740" Title="How can speed of geostrophic wind change when forces are always perpendicular to speed?" Tags="|meteorology|wind|atmosphere-modelling|fluid-dynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24644" PostTypeId="2" ParentId="709" CreationDate="2022-12-19T12:00:27.703" Score="1" Body="&lt;ol&gt;&#xA;&lt;li&gt;the strength of bonds that hold the meniral&lt;/li&gt;&#xA;&lt;li&gt;the structure of the mineral lattice&lt;/li&gt;&#xA;&lt;li&gt;crystal morphology&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="28165" LastEditorUserId="28165" LastEditDate="2022-12-19T12:06:40.177" LastActivityDate="2022-12-19T12:06:40.177" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24645" PostTypeId="2" ParentId="24643" CreationDate="2022-12-19T13:34:00.030" Score="2" Body="&lt;p&gt;You're confusing time-dependent and time independent equations: The time-dependent model tells you how &lt;span class=&quot;math-container&quot;&gt;$\vec U$&lt;/span&gt; will evolve, it doesn't have to evolve into a steady-state. The steady, time-independent model tells you which &lt;span class=&quot;math-container&quot;&gt;$\vec U$&lt;/span&gt; fulfills that equation as a criterion.&lt;br /&gt;&#xA;Therefore that &lt;span class=&quot;math-container&quot;&gt;$\vec U$&lt;/span&gt; usually gets a special name, the geostrophic velocity &lt;span class=&quot;math-container&quot;&gt;$\vec U_g$&lt;/span&gt;, and the time-dependent equation also can be reformulated into a form of &lt;span class=&quot;math-container&quot;&gt;$\vec U =\vec U' -\vec U_g$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;So when the current &lt;span class=&quot;math-container&quot;&gt;$\vec U_g$&lt;/span&gt; changes, we can see how &lt;span class=&quot;math-container&quot;&gt;$d_t \vec U$&lt;/span&gt; generates non-perpendicular terms until &lt;span class=&quot;math-container&quot;&gt;$\vec U = \vec U_g$&lt;/span&gt; and balance is restored.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In the moment I regard this as a discrepancy.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I don't presume you regard the existence of satellites as fantasy, to which your argument would equally apply? For a circular orbit, the centrifugal force is perpendicular to the velocity, so it's all a hoax?&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2022-12-19T13:34:00.030" CommentCount="16" ContentLicense="CC BY-SA 4.0" />
  <row Id="24646" PostTypeId="1" CreationDate="2022-12-19T14:25:44.147" Score="3" ViewCount="76" Body="&lt;p&gt;In the mountains, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Tree_line&quot; rel=&quot;nofollow noreferrer&quot;&gt;tree line&lt;/a&gt; marks the elevation above which there are no more trees growing. Do those little mountain pines such as the ones &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Custura_Bucurei.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;in this image&lt;/a&gt; (it failed to upload for some reason) count as &amp;quot;trees&amp;quot; here so that the tree line marks where those mountain pines end as well, or do they rather count as bushes that may grow higher than the tree line and the tree line is only about &amp;quot;normal&amp;quot; big trees?&lt;/p&gt;&#xA;" OwnerUserId="28130" LastActivityDate="2022-12-21T02:05:31.147" Title="When we're talking about the tree line, does it include mountain pines?" Tags="|mountains|vegetation|plant|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24651" PostTypeId="1" CreationDate="2022-12-19T20:48:01.370" Score="3" ViewCount="24" Body="&lt;p&gt;Do you know a way to find daily snow water equivalent data, for just snow and not any rain that may have fallen same day?&lt;/p&gt;&#xA;&lt;p&gt;Backstory:&lt;/p&gt;&#xA;&lt;p&gt;Hi, I'm pretty new to all this.  I work for a small city that wants to have better data to analyze our past snow-plowing operations.  For that we need to know how much snow there was.&lt;/p&gt;&#xA;&lt;p&gt;We have had a million debates (familiar to you I'm sure) about all the different kinds of snow, and we've decided it's not fair to compare snow-inches - i.e. it will take longer to remove a few inches of wet heavy snow than many inches of light, dry snow.&lt;/p&gt;&#xA;&lt;p&gt;Instead, we've decided to compare inches of equivalent water (what we call liquid equivalent inches but what I think is more properly called snow water equivalent).  So my question is how to find this data.&lt;/p&gt;&#xA;&lt;p&gt;I've found lots of data that shows both the snowfall inches and the precipitation.  So, seems like you could just look for days when there is snowfall, and then take the precipitation.  Here's a picture of NOAA data for an example.  You'd say that on Dec. 14, there was no snow, and on Dec. 15, there was 1 inch of snow, which was formed by 1.14 inches of precipitation.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FnStY.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FnStY.png&quot; alt=&quot;picture of NOAA data&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;However!  This data does not actually tell the whole story.  Because on Dec. 15, first it rained a bunch, and then gradually that became snow.  So the 1 inch of snow was formed by only some fraction of that 1.14 inches of precipitation.  I'm only interested in the snow water equivalent of the snow itself.&lt;/p&gt;&#xA;&lt;p&gt;So, what data can I used to get the snow water equivalent of just the snow?&lt;/p&gt;&#xA;&lt;p&gt;My best thought has been to find data that gives snow, rain, and total precipitation inches in separate columns.  Then I can find snow water equivalents by subtracting rain from total precip.  Except, I can't find any such data - it all seems to be just snow, and total precip.&lt;/p&gt;&#xA;&lt;p&gt;Do you know where I can find such data?  Or do you have a different idea?&lt;/p&gt;&#xA;" OwnerUserId="28145" LastEditorUserId="28145" LastEditDate="2022-12-19T21:12:53.543" LastActivityDate="2022-12-19T21:12:53.543" Title="Daily data for snow water equivalent (not including rain)" Tags="|climate|precipitation|snow|weatherdata|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24652" PostTypeId="1" CreationDate="2022-12-19T21:22:51.043" Score="2" ViewCount="76" Body="&lt;p&gt;I want to download multiple files for a specific area, one file daily for an specific variable like total rainfall in one month. I'm having problems with the for loop and changing the output file name stored in a desired folder.&lt;/p&gt;&#xA;&lt;p&gt;Expecting for example january-2022, having 31 files for total precipitation TPdata, like: TP_01_01.nc TP_01_02.nc .... TP_01_31.nc&lt;/p&gt;&#xA;" OwnerUserId="28173" LastActivityDate="2022-12-19T21:22:51.043" Title="Download faster era5 data" Tags="|precipitation|python|weatherdata|" AnswerCount="0" CommentCount="1" ClosedDate="2022-12-23T08:31:04.733" ContentLicense="CC BY-SA 4.0" />
  <row Id="24653" PostTypeId="2" ParentId="24646" CreationDate="2022-12-19T23:36:36.157" Score="7" Body="&lt;p&gt;From Ann H Zwinger and Beatrice E Willard, 1972, &lt;em&gt;Land Above the Trees,&lt;/em&gt; Harper and Row, New York. 1st edition. 1972. 489 pp.  The following is from page 59...&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Beyond treelimit, trees are so stunted that they are no longer trees but shrubs.  They are called &lt;em&gt;krummholz,&lt;/em&gt; a descriptive German word which means &amp;quot;elfin timber&amp;quot; or &amp;quot;crooked wood.&amp;quot; They look as if they had been cultivated by overly ambitious bonsai gardeners.  Krummholz growth habit is shrubby and dense, becoming more prostrate, more twisted and contorted, with altitude.  Treetops are flat or flagged or both; trunks are gnarled.  Basal branches form impenetrable masses of long intertwined serpentines...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="28175" LastEditorUserId="2470" LastEditDate="2022-12-21T02:05:31.147" LastActivityDate="2022-12-21T02:05:31.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24654" PostTypeId="1" CreationDate="2022-12-20T03:25:23.947" Score="1" ViewCount="26" Body="&lt;p&gt;Schumann resonances vary with losses in the cavity between Earth and the ionosphere and variability of the upper boundary due to atmospheric conductivity and ionospheric dynamics:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;BALSER, M., WAGNER, C.&lt;br /&gt;&#xA;Observations of Earth–Ionosphere Cavity Resonances.&lt;br /&gt;&#xA;Nature 188, 638–641 (1960).&lt;br /&gt;&#xA;&lt;a href=&quot;https://doi.org/10.1038/188638a0&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1038/188638a0&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Especially during warmer and thus wetter periods the Schumann resonances might have been lower due to increased atmospheric conductivity.&lt;/p&gt;&#xA;&lt;p&gt;What different values have the Schumann resonances had in Earths history?&lt;/p&gt;&#xA;" OwnerUserId="27409" LastActivityDate="2022-12-20T03:25:23.947" Title="How have Schumann resonances varied in previous eras and periods on Earth?" Tags="|earth-history|electromagnetism|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24655" PostTypeId="1" CreationDate="2022-12-20T06:40:14.163" Score="1" ViewCount="56" Body="&lt;p&gt;My conception is that the two factors affecting seasons should be the following:&#xA;&lt;br&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The relative duration of day and night throughout one rotation&lt;/li&gt;&#xA;&lt;li&gt;The angle made by the sunlight w.r.t the normal to the surface.&lt;br&gt;&#xA;I can understand that the Equator will experience two instances of temperature peaks(or two summers, as one may call it,) throughout the revolution of the Earth. This is because the duration of day and night is the same on the Equator throughout, so the angle at which it receives sunlight becomes the controlling factor. During the solstices when the point on the Equator experiences noon it receives sunlight at a certain angle whereas its directly overhead during the Equinoxes. Thus the spike in temperature is explained.&lt;br&gt;&#xA;However this isn't the case for other regions. Northern hemispheres always have a longer daytime during solstices. Yet the region between the Tropic of Cancer and the Equator experiences two peaks of temperature. Please explain what's going on.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="22530" LastActivityDate="2022-12-20T06:40:14.163" Title="On the occurrence of 'two summers' on certain regions of the Earth" Tags="|climate|seasons|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24656" PostTypeId="1" CreationDate="2022-12-20T11:57:53.300" Score="4" ViewCount="327" Body="&lt;p&gt;When I view Earth from a distance in my mind, I always think of the North pole as being &amp;quot;up&amp;quot;, and South pole as being &amp;quot;down&amp;quot;. Yes, I know Earth is tilted, but it's still up/down.&lt;/p&gt;&#xA;&lt;p&gt;This means my &amp;quot;camera&amp;quot; is always placed in a certain way in this endless void. But it's based on nothing other than my perception that there is a &amp;quot;North&amp;quot; or &amp;quot;up&amp;quot; on Earth.&lt;/p&gt;&#xA;&lt;p&gt;But why are they referred to as the North/South poles? Did they just pick these at random? Could the South pole just as well have been the North pole to humans?&lt;/p&gt;&#xA;&lt;p&gt;I don't think it really matters, but it's something which I've often thought about and cannot find the answer to.&lt;/p&gt;&#xA;" OwnerUserId="28178" LastActivityDate="2022-12-26T15:17:09.410" Title="Were the &quot;North&quot; and &quot;South&quot; poles' names picked randomly or based on some science?" Tags="|poles|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24657" PostTypeId="2" ParentId="24638" CreationDate="2022-12-20T20:54:19.940" Score="3" Body="&lt;p&gt;The subscript &lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt; denotes that it on a pressure surface. It is more or less a formality for a derivation, so it is commonly dropped. It is rooted in the chain rule&lt;/p&gt;&#xA;&lt;p&gt;Put another way, it eliminates the complexity of this conundrum &lt;span class=&quot;math-container&quot;&gt;$\Phi=\Phi(x,y,p[x,y])$&lt;/span&gt;. By specifically stating that you are working on an isobaric surface, you turn&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial \Phi}{\partial x}= (\frac{\partial \Phi}{\partial x})_{p=constant} + \frac{ \partial \Phi}{\partial p} (\frac{\partial p}{\partial x})_{z=constant} $$&lt;/span&gt;&#xA;into&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{\partial \Phi}{\partial x}= (\frac{\partial \Phi}{\partial x})_{p} $$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;If you take this concept of chain rule and make it abstract, you could expand it to working on all sorts of surfaces. You could turn the equations from pressure coordinates to PV or temperature coordinates, for example.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2022-12-20T20:54:19.940" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24658" PostTypeId="1" CreationDate="2022-12-21T11:38:31.420" Score="2" ViewCount="38" Body="&lt;p&gt;I am picking up on remote sensing. I came across a paper where they use the shaded relief model from Terrain Resource Information Management (TRIM) for hillshading. However, is it the same as the hillshade function that can be applied to the DEM in QGIS/ArcGIS?&#xA;If I have the images from the two methods (TRIM and GIS), would i be looking at the same images?&lt;/p&gt;&#xA;&lt;p&gt;Your reply will be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="28184" LastEditorUserId="28184" LastEditDate="2022-12-21T11:42:00.950" LastActivityDate="2022-12-21T11:42:00.950" Title="Difference between Hillshading and Terrain Resource Information Management" Tags="|geology|geography|remote-sensing|mapping|gis|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24659" PostTypeId="1" AcceptedAnswerId="24660" CreationDate="2022-12-21T12:27:49.750" Score="3" ViewCount="259" Body="&lt;p&gt;*I want to understand what would it mean by easting of ground control points (GCP), and what would it mean to have rmse of x m with a minimum of a m.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The average root mean square errors (RMSE) in the easting and northing&#xA;of the GCPs were 'x' and 'y' m, respectively, with a minimum value of 'a' m&#xA;and a maximum value of 'b' m.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="28184" LastEditorUserId="543" LastEditDate="2022-12-23T01:05:58.243" LastActivityDate="2022-12-23T21:04:15.257" Title="What is this error regarding easting and northing of ground control points?" Tags="|remote-sensing|data-analysis|statistics|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24660" PostTypeId="2" ParentId="24659" CreationDate="2022-12-21T15:15:11.073" Score="3" Body="&lt;p&gt;Easting and northing provide an alternative to latitude and longitude for specifying a point on the Earth ellipsoid. I suggest you read (for example) the wiki.gis.com pages on the &lt;a href=&quot;http://wiki.gis.com/wiki/index.php/Universal_Transverse_Mercator&quot; rel=&quot;nofollow noreferrer&quot;&gt;Universal Transverse Mercator (UTM) coordinate system&lt;/a&gt; and &lt;a href=&quot;http://wiki.gis.com/wiki/index.php/Easting_and_northing&quot; rel=&quot;nofollow noreferrer&quot;&gt;easting and northing&lt;/a&gt;. There are lots of other articles on these topics on the internet.&lt;/p&gt;&#xA;&lt;p&gt;There are advantages and disadvantages with regard to easting and northing versus latitude and longitude. One key advantage of easting and northing is that for nearby points such as the error in ground control points, easting and northing take advantage of the fact that the surface of the Earth is nearly flat on a local scale. One key disadvantage of easting and northing is that it's rather convoluted.&lt;/p&gt;&#xA;&lt;p&gt;Because this concept is already well-documented, and because it is rather convoluted, I'm not going to go into details in this answer. I suggest instead that you read up on the topic and ask additional questions when you come up with them.&lt;/p&gt;&#xA;&lt;p&gt;Regarding the specific issue raised in the question,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The average root mean square errors (RMSE) in the easting and northing of the GCPs were 'x' and 'y' m, respectively, with a minimum value of 'a' m and a maximum value of 'b' m.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Another way to put the first part of the quoted text is that the ground control points have a root mean square error of &lt;code&gt;x&lt;/code&gt; meters in the east-west direction and &lt;code&gt;y&lt;/code&gt; meters in the north-south direction. I would have to see the relevant text to properly interpret the second part (the part about minimum and maximum errors). I suspect that those are the minimum and maximum of the square roots of the sum of the squares of the easting and northing errors, but that's just a guess.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2022-12-23T21:04:15.257" LastActivityDate="2022-12-23T21:04:15.257" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24661" PostTypeId="2" ParentId="24656" CreationDate="2022-12-22T15:23:57.997" Score="6" Body="&lt;p&gt;The Earth is more or less spherical, and more or less rotates steadily about an axis between the north and south poles, with a very long term (26000 years) precession and shorter term nutations. That the Earth is more or less spherical and that it rotates about an axis was known to the ancients.&lt;/p&gt;&#xA;&lt;p&gt;This daily rotation makes the Sun rise more or less in the east, set more or less in the west, and at noon in places north of the tropics, the Sun is south of the zenith (vertical). Northward is where it gets colder the further north one goes. In addition, the northern hemisphere is blessed in having Polaris as a guide star by which one can determine which way is north.&lt;/p&gt;&#xA;&lt;p&gt;This north-south, east-west set of directions were very important to seagoing civilizations. Regarding maps, which direction was at the top of a map and which direction was to the right varied from civilization to civilization. Some had south at the top and north at the bottom. Others had east at the top and the west at the bottom. Yet others had north at the top and south at the bottom. It wasn't until Mercator's time (mid to late 16th century) that European mapmakers settled on arbitrarily placing north that the top of a map and east to the right. That was about the same time that western European hegemony started, which is why modern maps almost universally have north at the top. It's a bit arbitrary, a bit chance that north is at the top of most maps.&lt;/p&gt;&#xA;&lt;p&gt;Regarding etymology, this is the wrong site for that kind of question.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2022-12-26T15:17:09.410" LastActivityDate="2022-12-26T15:17:09.410" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24662" PostTypeId="1" CreationDate="2022-12-22T16:38:40.377" Score="1" ViewCount="27" Body="&lt;p&gt;There are four 'Lateral inflow' related variables coming out from the .res1d file&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Lateral inflow SHE overland&lt;/li&gt;&#xA;&lt;li&gt;Lateral inflow SHE saturated zone&lt;/li&gt;&#xA;&lt;li&gt;Lateral inflow SHE overland drain&lt;/li&gt;&#xA;&lt;li&gt;Lateral inflow SHE saturated zone drain&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;I am trying to get estimate how much water is entering the different watersheds in the model domain that I am working on. However, I don't quite understand the difference between these four variables, especially, the difference between the 'overland' vs 'overland drain' and  'saturated zone' vs 'saturated zone drain'&lt;/p&gt;&#xA;" OwnerUserId="27888" LastActivityDate="2022-12-22T16:38:40.377" Title="MIKE SHE Lateral inflow outputs and the differences between them" Tags="|hydrology|groundwater|numerical-modelling|flooding|watershed|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24664" PostTypeId="1" CreationDate="2022-12-24T10:10:27.490" Score="1" ViewCount="46" Body="&lt;p&gt;I answered to this question some time ago:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/questions/21136/who-are-winners-from-the-global-warming-are-there-any/24488#24488&quot;&gt;Who are winners from the global warming? Are there any?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The user asked if Russia would benefit from climate change.&lt;/p&gt;&#xA;&lt;p&gt;I found a paper that asserts:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Our simulations with the ECHAM5 general circulation model demonstrate that lower‐troposphere heating over the B‐K seas in the Eastern Arctic caused by the sea ice reduction may result in strong anticyclonic anomaly over the Polar Ocean and anomalous easterly advection over northern continents. This causes a continental‐scale winter cooling reaching −1.5°C, with more than 3 times increased probability of cold winter extremes over large areas including Europe. &lt;strong&gt;Our results imply that several recent severe winters do not conflict the global warming picture but rather supplement it&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Source&lt;/strong&gt;: &lt;a href=&quot;https://doi.org/10.1029/2009JD013568&quot; rel=&quot;nofollow noreferrer&quot;&gt;A link between reduced Barents‐Kara sea ice and cold winter extremes over northern continents&amp;quot;, &lt;em&gt;Climate and Dynamics&lt;/em&gt;&lt;/a&gt;, cited in &lt;a href=&quot;https://www.independent.co.uk/climate-change/news/expect-more-extreme-winters-thanks-to-global-warming-say-scientists-2168418.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Expect more extreme winters thanks to Global Warming, say scientists, Independent&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The paper only mentions large areas of the Northern Hemisphere including Europe, but the current cold wave in United States makes me wonder if this is something global and also affecting the Southern Hemisphere.&lt;/p&gt;&#xA;&lt;p&gt;I am sure climate change make the winters shorter, but are those short winters more extreme?&lt;/p&gt;&#xA;&lt;p&gt;Is this something global or only regional because of the anticyclonic anomaly over the Polar Ocean?&lt;/p&gt;&#xA;" OwnerDisplayName="user28185" LastEditorUserId="2470" LastEditDate="2022-12-24T18:43:54.673" LastActivityDate="2022-12-24T18:43:54.673" Title="Does climate change generate more cold waves?" Tags="|climate-change|climatology|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24665" PostTypeId="2" ParentId="13696" CreationDate="2022-12-24T12:25:16.987" Score="0" Body="&lt;p&gt;Wallace and Hobbes is a very good book for general aknowledge. I strongly recommend it. I study oceanograpy down in Brazil and my professor use it with us so we can get the main atmospheric concepts, but it is what it is: introductory. If you want to do real weather prediction efforts, you need to search for graduation courses in the area, since it is one of the most complexes sciences we have.&lt;/p&gt;&#xA;" OwnerUserId="28193" LastActivityDate="2022-12-24T12:25:16.987" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24666" PostTypeId="2" ParentId="7919" CreationDate="2022-12-24T15:58:19.220" Score="4" Body="&lt;p&gt;The sky appears white because immediately after the rain stops and the clouds have started to dissipate, there are often water aerosols (i.e. diffuse clouds) still lingering in the atmosphere. Unlike &lt;a href=&quot;http://hyperphysics.phy-astr.gsu.edu/hbase/atmos/blusky.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Rayleigh Scattering&lt;/a&gt; from sub-wavelength sized air molecules which makes the sky blue because of its strong wavelength dependence, &lt;a href=&quot;https://en.wikipedia.org/wiki/Mie_scattering&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mie scattering&lt;/a&gt; and &lt;a href=&quot;https://www.mkrgeo-blog.com/light-scattering-in-the-earths-atmosphere-part-3-clouds-haze-and-surface/&quot; rel=&quot;nofollow noreferrer&quot;&gt;non-selective scattering&lt;/a&gt; from larger particles such as water aerosol droplets scatter all wavelengths relatively equally.  This is &lt;a href=&quot;https://www.mkrgeo-blog.com/light-scattering-in-the-earths-atmosphere-part-3-clouds-haze-and-surface/&quot; rel=&quot;nofollow noreferrer&quot;&gt;why clouds are white&lt;/a&gt; when illuminated by sunlight.&lt;/p&gt;&#xA;" OwnerUserId="27775" LastActivityDate="2022-12-24T15:58:19.220" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24667" PostTypeId="2" ParentId="24485" CreationDate="2022-12-24T18:27:56.737" Score="2" Body="&lt;p&gt;The reason why there are lands comprised of continental crust submerged far away from the coast is we are in an interglacial period inside the &lt;a href=&quot;https://en.wikipedia.org/wiki/Pleistocene&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pleistocene&lt;/a&gt; cycle.&lt;/p&gt;&#xA;&lt;p&gt;There are extensive &lt;a href=&quot;https://en.wikipedia.org/wiki/Continental_shelf&quot; rel=&quot;nofollow noreferrer&quot;&gt;continental shelves&lt;/a&gt; that were formed during glacial periods when the sea level was lower.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.marinebio.org/oceans/continental-shelves/#:%7E:text=Continental%20shelves%20were%20formed%20in,shelf%20was%20actually%20above%20water.&quot; rel=&quot;nofollow noreferrer&quot;&gt;For more information.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user28185" LastEditorUserId="2470" LastEditDate="2022-12-24T23:09:50.060" LastActivityDate="2022-12-24T23:09:50.060" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24668" PostTypeId="1" CreationDate="2022-12-25T13:53:00.800" Score="-1" ViewCount="121" Body="&lt;p&gt;The Earth is has a globular shape and sea water level is a plane.&lt;/p&gt;&#xA;&lt;p&gt;We are on the upper surface of the Earth, then how is sea water level a plane?&lt;/p&gt;&#xA;" OwnerUserId="28201" LastEditorUserId="2470" LastEditDate="2022-12-27T00:33:03.220" LastActivityDate="2023-01-25T14:05:09.007" Title="How is sea water level on the Earth a plane?" Tags="|oceanography|earth-observation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24669" PostTypeId="1" CreationDate="2022-12-25T15:19:15.377" Score="5" ViewCount="239" Body="&lt;p&gt;What are the differences between the conditions that lead to &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake-effect_snow&quot; rel=&quot;noreferrer&quot;&gt;lake effect&lt;/a&gt; snow versus ocean effect snowfall?&#xA;Both can lead to significant snowfall, but usually lake effect causes large snow amounts.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2022-12-26T16:48:33.207" Title="Differences between lake effect and ocean effect snow" Tags="|oceanography|snow|lakes|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24670" PostTypeId="2" ParentId="24668" CreationDate="2022-12-25T16:00:32.423" Score="5" Body="&lt;p&gt;Water level is flat with regard to the balance between several forces predominantly gravity (other smaller effects include baroclinic effects). The direction of &lt;a href=&quot;https://en.wikipedia.org/wiki/Gravity_of_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth's gravity&lt;/a&gt; is a combination of gravitational pull and inertia (centrifugal &amp;quot;forces&amp;quot;). The gravitational pull is toward the relative &lt;a href=&quot;https://www.scientificamerican.com/article/football-center-of-mass/&quot; rel=&quot;nofollow noreferrer&quot;&gt;center of mass of the earth-moon system&lt;/a&gt; depending on the relative position of the Moon with respect to the local position on Earth's surface.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AYBcB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AYBcB.png&quot; alt=&quot;simplified gravity figure&quot; /&gt;&lt;/a&gt; Simplified sea level for a stationary uniform Earth covered by water. &lt;a href=&quot;https://blogs.egu.eu/divisions/cr/2016/10/19/sea-level-for-dummies/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Gravity does change slightly in different areas based on Earth's density (more info in &lt;a href=&quot;https://earthscience.stackexchange.com/questions/7449/does-gravity-differ-from-place-to-place-on-earth/7454&quot;&gt;this answer&lt;/a&gt;). A good explanation of why water level is &amp;quot;flat&amp;quot; is found &lt;a href=&quot;https://blogs.egu.eu/divisions/cr/2016/10/19/sea-level-for-dummies/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The ocean is not like a bathtub. At shorter time scales the water level surface responds as a balance between multiple forces (&lt;a href=&quot;https://oceanservice.noaa.gov/education/tutorial_tides/tides01_intro.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;tides&lt;/a&gt;, wind stress, friction, baroclinic torque, ...). The balance is complex and highly local:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/cIxXR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cIxXR.png&quot; alt=&quot;Hycom global sea level Nov 20, 2018&quot; /&gt;&lt;/a&gt; &lt;a href=&quot;https://www7320.nrlssc.navy.mil/GLBhycom1-12/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="111" LastEditDate="2023-01-25T14:05:09.007" LastActivityDate="2023-01-25T14:05:09.007" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24672" PostTypeId="2" ParentId="7673" CreationDate="2022-12-25T20:09:55.457" Score="3" Body="&lt;p&gt;The CM-CF offset for Earth is 2.1 km, that is that Earth's center of mass as determined by an analysis of the Earth's gravitational potential energy that is represented as a finite sum of spherical harmonics. The rotational geometric centre of figure is obtained by analysis of the hypsometry or topography and bathymetry and calculating the geometric centre of the planet.&#xA;The offset arises because mass inside the Earth is not homogeneously distributed (e.g., mantle plumes, subducting lithosphere, dynamically displace lithosphere because of glacial isostatic rebound etc..). The later distorts the Earth's equilibrium shape away from a simple spheroid.&#xA;Good books on the subject are:&#xA;Physics of Earth by Stacey and Davis Cambridge Press&#xA;Geodynamics by Turcott and Schubert Cambridge Press&lt;/p&gt;&#xA;&lt;p&gt;For details of how those parameters are calculated&#xA;Warning: Mathematical sophistication required is high.&lt;/p&gt;&#xA;&lt;p&gt;Wieczorek, M. A. (2007). Gravity and topography of the terrestrial planets.&#xA;In Treatise on Geophysics (Vol. 10, pp. 165–206). Oxford, UK: Elsevier.&#xA;&lt;a href=&quot;https://doi.org/10.1016/B978-044452748-6.00156-5&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/B978-044452748-6.00156-5&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28203" LastActivityDate="2022-12-25T20:09:55.457" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24673" PostTypeId="1" AcceptedAnswerId="24675" CreationDate="2022-12-25T21:51:36.707" Score="7" ViewCount="533" Body="&lt;p&gt;I noticed on World Weather Map over the last 2 days Russia has had an isolated circular warm spot which seems very uniform and hasn't changed for at least 2 days: &lt;a href=&quot;https://map.worldweatheronline.com/temperature?lat=-3.337953961416472&amp;amp;lng=79.62890625000001&quot; rel=&quot;nofollow noreferrer&quot;&gt;see here&lt;/a&gt; and in below image.&lt;/p&gt;&#xA;&lt;p&gt;Any ideas if this is a technical error or else some natural or man made phenomenon?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/huCJ5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/huCJ5.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;EDIT: for clarity i am referring to this spot:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/H49r1.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/H49r1.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28204" LastEditorUserId="28204" LastEditDate="2022-12-26T09:27:32.780" LastActivityDate="2023-12-15T13:53:56.107" Title="What is this warm circle in the middle of Russia?" Tags="|meteorology|weather-satellites|" AnswerCount="3" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="24675" PostTypeId="2" ParentId="24673" CreationDate="2022-12-26T10:54:52.813" Score="4" Body="&lt;p&gt;Interestingly, there is a pressure anomaly that corresponds with the temperature anomaly. The pressure of the spot is about 30 hPa lower that the surrounding region indicating a localized low pressure cell, suggesting that something on the surface is heating the atmosphere sufficiently to cause this.&lt;/p&gt;&#xA;&lt;p&gt;By taking co-ordinates around the edge of the spot, east-west and north and south, and doing a bit of math, the average diameter of the spot is 215 km.&lt;/p&gt;&#xA;&lt;p&gt;Taking the co-ordinates from your comment (65.5857 N, 117.02636 E) and looking at Google Earth, there is an &lt;a href=&quot;https://en.wikipedia.org/wiki/Alrosa&quot; rel=&quot;nofollow noreferrer&quot;&gt;Alrosa&lt;/a&gt; diamond mine at co-ordinates 65° 01’ 11” N, 117° 05’ 04” E (65.01972 N, 117.08444 E) that Google Earth does not list the name of.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cQ8Fk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cQ8Fk.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Given the isolated nature of this mine my speculation is this mine is associated with the anomalous spot you noticed.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2022-12-28T01:49:00.760" LastActivityDate="2022-12-28T01:49:00.760" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24676" PostTypeId="1" CreationDate="2022-12-26T14:26:22.523" Score="1" ViewCount="15" Body="&lt;p&gt;Could the presence of mountain ranges in continental areas near to tectonic plates boundaries prevent these plates from swaying up and down as a result of vertical tidal forces and plastic Asthenosphere?&lt;/p&gt;&#xA;" OwnerUserId="28208" LastActivityDate="2022-12-26T14:26:22.523" Title="Relation between highlands and tidal forces" Tags="|geology|geophysics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24677" PostTypeId="2" ParentId="24669" CreationDate="2022-12-26T16:48:33.207" Score="5" Body="&lt;p&gt;Well, for one is the salination. The salt in oceans lowers the vapor pressure, lowering the evaporation rates (i.e. the salinated water is hindered from evaporating).&lt;/p&gt;&#xA;&lt;p&gt;Another is the amount of fetch. Over a large enough ocean, the air is modified by the surface temperature of the water. With a lake, the amount of surface is usually not as great, so the air is not warmed as much by the lake. That is, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Air_mass#Characteristics&quot; rel=&quot;noreferrer&quot;&gt;classification of the air&lt;/a&gt; that causes lake effect snow is continental polar (cP) or Arctic (A). However, ocean-effect snow is most like maritime polar (mP), which tends to be more mild. One instance where this tends to not be a major factor is &lt;a href=&quot;https://en.wikipedia.org/wiki/Snow_country_(Japan)&quot; rel=&quot;noreferrer&quot;&gt;Japan’s snow country&lt;/a&gt;, where the fetch from the Sea of Japan tends to be optimized for snow.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2022-12-26T16:48:33.207" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24678" PostTypeId="2" ParentId="24023" CreationDate="2022-12-26T18:20:44.850" Score="2" Body="&lt;p&gt;You wrote:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;I have recently learned that the magma produced at subduction zones&#xA;comes from the partial melting of the mantle above the subducting&#xA;plate and that very little comes from the plate itself.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It would be interesting if you could provide a source for this claim, as it is still unclear (Guo et al., 2022).&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Island_arc&quot; rel=&quot;nofollow noreferrer&quot;&gt;island arcs&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Volcanic_arc&quot; rel=&quot;nofollow noreferrer&quot;&gt;volcanic arcs&lt;/a&gt; are far from the mid-ocean ridge, and the plate that subducts has had time to accumulate a large stack of sediments. &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiolaria&quot; rel=&quot;nofollow noreferrer&quot;&gt;This source from the University of Dallas&lt;/a&gt; suggests that when the plate subducts, the melting of the oceanic crust with sediments becomes one of the sources of calc-alkaline and alkaline magmas that crystallize on the surface as &lt;a href=&quot;https://en.wikipedia.org/wiki/Felsic&quot; rel=&quot;nofollow noreferrer&quot;&gt;felsic&lt;/a&gt; rocks. However, the volcanologist @Jean-Marie Prival doubts this assertion is true (see comments moved to chat).&lt;/p&gt;&#xA;&lt;p&gt;Some studies suggest that andesites come from a mantle source and not the slab:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The sum of stratigraphic, geochemical, and isotopic evidence on&#xA;Agrigan supports the derivation of calc-alkaline andesite by the&#xA;removal of about 75% solids from a high-alumina basalt accompanied by&#xA;a process of K and Rb enrichment, such as volatile-transfer.&#xA;&lt;strong&gt;Considerations of 87Sr/86Sr, 143Nd/144Nd, and 3He/4He isotopic data&#xA;indicate that the source region of these parental liquids lies in the mantle, not subducted crust.&lt;/strong&gt; (Stern, R.J., 1979).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;What is certain is that the sediments of the subducted plate are hydrated. When the subducted plate melts, the magma is enriched in H&lt;sub&gt;2&lt;/sub&gt;O due to dehydration of the slab, contributing to the explosive eruptions that form &lt;a href=&quot;https://en.wikipedia.org/wiki/Stratovolcano&quot; rel=&quot;nofollow noreferrer&quot;&gt;stratovolcanoes&lt;/a&gt; in both island arcs and volcanic arcs.&lt;/p&gt;&#xA;&lt;p&gt;H&lt;sub&gt;2&lt;/sub&gt;O also affects the magma differentiation:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Subduction zones (arcs and back-arcs) are major sites for elemental cycling via &lt;strong&gt;slab dehydration and subsequent mantle metasomatism and melting&lt;/strong&gt;; many models have been suggested by researchers to explain these processes. &lt;strong&gt;However, the influence of the overriding lithosphere, especially the lower crust, on the generation of back-arc magmas during the early spreading stage remains largely unknown&lt;/strong&gt; (Guo,K. et al, 2022).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You also wrote:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;This means that mid-ocean ridges, hot spots, and subduction zones all derive their magma directly from the mantle, yet they somehow produce magmas of differing compositions.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Both &lt;a href=&quot;https://en.wikipedia.org/wiki/Hotspot_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;hot spots&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Mid-ocean_ridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;mid-ocean ridges&lt;/a&gt; produce basaltic magmas derived from the mantle. It is still debated whether the composition of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Slab_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;slab&lt;/a&gt; in subduction zones affects the magma that generates the resulting felsic rocks. It might affect them residually. What is certain is that &amp;quot;somehow&amp;quot; refers to the subducted slab, and more specifically, the H&lt;sub&gt;2&lt;/sub&gt;O accumulated in the sediments that alters the mantle magma differentiation.&lt;/p&gt;&#xA;&lt;p&gt;A final consideration is that the temperature of the mantle varies greatly, from 1000°C near its boundary with the crust to 3700°C near its boundary with the core (&lt;a href=&quot;https://education.nationalgeographic.org/resource/mantle&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;). This raises the question of whether this temperature is enough to melt sediments.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The melting point of radiolaria SiO&lt;sub&gt;2&lt;/sub&gt; shells is 1.710 °C. The source of the Si enrichment can hardly be the sediments of the slag.&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://pubs.geoscienceworld.org/books/book/1144/chapter-abstract/10571036/Preservation-of-Foraminifera?redirectedFrom=PDF&quot; rel=&quot;nofollow noreferrer&quot;&gt;This paper&lt;/a&gt; sugest some CaCO&lt;sub&gt;3&lt;/sub&gt; shells are preserved even the trench is under the &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonate_compensation_depth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Carbonate Compensation Depth&lt;/a&gt;. They migth enrich the magma in Ca, as CaCO&lt;sub&gt;3&lt;/sub&gt; melting point is 825ºC.&lt;/li&gt;&#xA;&lt;li&gt;Sedimentary clays have a melting point between 1250 °C to 1350 °C. They may enrich the magma in elements as Al or K.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;-Eichelberger, J.C. Andesites in island arcs and continental margins: Relationship to crustal evolution. Bull Volcanol 41, 480–500 (1978). &lt;a href=&quot;https://doi.org/10.1007/BF02597382&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1007/BF02597382&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;-Stern, R.J. On the origin of andesite in the northern Mariana Island Arc: Implications from Agrigan. Contr. Mineral. and Petrol. 68, 207–219 (1979). &lt;a href=&quot;https://doi.org/10.1007/BF00371901&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1007/BF00371901&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;-Kun Guo, Xiaoyuan Wang, Shuai Chen, Luning Shang, Bingquan Liu, Xia Zhang, Zhiqing Lai (2022): &amp;quot;The delamination of lower crust in continental back-arc basin: Evidence from Sr isotope and elemental compositions of plagioclase and clinopyroxene in andesites from Kueishantao, north of Taiwan, China,&amp;quot; Lithos, Volumes 416–417, ISSN 0024-4937, &lt;a href=&quot;https://doi.org/10.1016/j.lithos.2022.106653&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/j.lithos.2022.106653&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user28185" LastEditorDisplayName="user28185" LastEditDate="2023-03-15T09:20:00.913" LastActivityDate="2023-03-15T09:20:00.913" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24679" PostTypeId="1" AcceptedAnswerId="24680" CreationDate="2022-12-26T21:07:56.200" Score="3" ViewCount="562" Body="&lt;p&gt;I watched a documentary this morning about how the water level on Lake Mead keeps dropping due to a historical 20+ year long drought. The lake's water level has been dropping due to a decrease in precipitation over the Rocky Mountains, an increase in the rate of water evaporation of Lake Mead, and also due to an increase in the need for fresh water for a growing population in the Greater Las Vegas region.&lt;/p&gt;&#xA;&lt;p&gt;Lake Mead provides the vast majority of the drinking water for the Greater Las Vegas region and the population there will continue to grow at a high rate for the foreseeable future:&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&amp;quot;Accounting for these factors and anticipating future trends, the population of the Las Vegas-Henderson-Paradise metro area in Nevada is projected to grow from 2,335,600 in 2022 to 4,450,000 in 2060. The 90.5% projected population growth in the metro area is the fifth highest of all 384 U.S. metro areas.&amp;quot;&lt;/em&gt; - &lt;a href=&quot;https://www.thecentersquare.com/nevada/las-vegas-nv-will-be-among-the-fastest-growing-cities-by-2060/article_daa06351-54fc-5b41-95ae-f8f07eab4fdf.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.thecentersquare.com/nevada/las-vegas-nv-will-be-among-the-fastest-growing-cities-by-2060/article_daa06351-54fc-5b41-95ae-f8f07eab4fdf.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The federal government should have a plan of action in place for supplying enough fresh water for the growing population of the Greater Las Vegas region, and also should have a plan of action for supplying enough water for the continued operation of the Hoover Dam, in the event of Lake Mead drying up in the near future. I am curious to know what those two plans are.&lt;/p&gt;&#xA;&lt;p&gt;What are the U.S. government's plans for dealing with the event of Lake Mead drying up in the near future?&lt;/p&gt;&#xA;" OwnerUserId="23275" LastEditorUserId="23275" LastEditDate="2022-12-27T11:41:50.563" LastActivityDate="2022-12-27T11:41:50.563" Title="What are the U.S. government's plans for dealing with the event of Lake Mead drying up in the near future?" Tags="|climate-change|water|geoengineering|united-states|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24680" PostTypeId="2" ParentId="24679" CreationDate="2022-12-27T00:23:53.497" Score="2" Body="&lt;p&gt;The water supplied by the Colorado River is regulated by international treaties, tribal treaties, federal regulations, interstate agreements, and intrastate agreements. California gets the lion's share. Las Vegas doesn't get nearly as much as does California. The people of Las Vegas will have to make due with their limited allotment. The city has already done much to reduce per-person water consumption. Green lawns are already becoming a thing of the past in Las Vegas. California most likely will have to reduce its consumption as well. (Say hello to higher produce prices.)&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-12-27T00:23:53.497" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24682" PostTypeId="1" CreationDate="2022-12-27T11:46:49.270" Score="4" ViewCount="209" Body="&lt;p&gt;&lt;img src=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/6/6e/Greenhouse_gas_emission_scenarios_01.svg/282px-Greenhouse_gas_emission_scenarios_01.svg.png&quot; alt=&quot;Greenhouse gas emission scenarios&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/File:Greenhouse_gas_emission_scenarios_01.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;This image in wikipedia&lt;/a&gt; shows that the temperature is going to increase 4.1-4.8 °C in 2100 if no policies are taken.&lt;/p&gt;&#xA;&lt;p&gt;How much raise in temperature can be reached in later times?&lt;/p&gt;&#xA;&lt;p&gt;Is there some limitation to temperature increase?&lt;/p&gt;&#xA;&lt;p&gt;For example, as far as I know, it is considered that the amount of available fossil fuels in the Earth is limited. What will happen if humans burn all the resources they can find to produce more CO&lt;sub&gt;2&lt;/sub&gt;?&lt;/p&gt;&#xA;&lt;p&gt;What is the maximum damage level, the maximum warming that can be reached by the oxidation of carbon by humans?&lt;/p&gt;&#xA;&lt;p&gt;To extrapolate the graph, the upper border of the pink red area is going to be like 9 °C in 2200, and bottom border is going to be like 1 °C. It gets its peak in 2080 and then goes down.&lt;/p&gt;&#xA;&lt;p&gt;So, can I ask some questions about this, if you agree with this prediction?&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;About the upper border: how far up can it go? Can it go to values&#xA;like 20, 50, 100, 200 °C?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;About the bottom border: why does it go down? I guess because plants&#xA;and algae (may) start to grow better (because of the warm climate and&#xA;abundance of CO&lt;sub&gt;2&lt;/sub&gt; and they suck in all the CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="18752" LastEditorUserId="2470" LastEditDate="2022-12-29T01:23:58.313" LastActivityDate="2023-02-09T20:24:17.070" Title="How dangerous is it that no global warming prevention measures are taken? What is the maximal warming, the limit?" Tags="|climate-change|fossil-fuel|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24683" PostTypeId="1" AcceptedAnswerId="24721" CreationDate="2022-12-27T15:11:35.183" Score="4" ViewCount="162" Body="&lt;p&gt;I have been making RGB photos of AVHRR images from &lt;a href=&quot;https://avl.class.noaa.gov&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA CLASS&lt;/a&gt; using the preview images (channel 2 &amp;amp; channel 4)&lt;a href=&quot;https://i.stack.imgur.com/Egrkq.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Egrkq.gif&quot; alt=&quot;As you can see, it isn't very good.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As you can see, it isn't very good. I have been wanting to use channel 1 and channel 3 images, but the only way to access such images is by ordering the images. I tried opening the images of inventory ID 0295859. When I ordered the images and download them, they have a file name of-&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;NSS.GHRR.NH.D89112.S0445.E0637.B0295859.WI&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;I tried opening the images, but nothing I did worked. I've tried extracting the files and attempted to open them using QGIS and ArcGIS, but nothing happened.&lt;/p&gt;&#xA;&lt;p&gt;The image would look like this colorized:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/fAWjZ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fAWjZ.jpg&quot; alt=&quot;Example&quot; /&gt;&lt;/a&gt;]&lt;/p&gt;&#xA;&lt;p&gt;How do I open this file? If it helps, the image is from 1989.&lt;/p&gt;&#xA;&lt;p&gt;Edit: Here's an updated version:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/2pQAh.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2pQAh.png&quot; alt=&quot;&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28212" LastEditorUserId="28212" LastEditDate="2023-09-24T06:34:31.190" LastActivityDate="2023-09-25T06:57:10.670" Title="How to open AVHRR files downloaded from NOAA CLASS?" Tags="|meteorology|tropical-cyclone|weather-satellites|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24684" PostTypeId="2" ParentId="24683" CreationDate="2022-12-27T17:30:27.173" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;As you can see, it isn't very good.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;From my perspective, it is very good. The raw data is AVHRR data scanned on a line-by-line and pixel-by-pixel sense. To make better sense of that data you might want to map the data to a grid. There are many people who want the raw data.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-12-27T17:30:27.173" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24685" PostTypeId="1" AcceptedAnswerId="24687" CreationDate="2022-12-27T17:49:39.093" Score="2" ViewCount="224" Body="&lt;p&gt;I am trying to reconstruct the astronomical tide time series from harmonic constituents (calculated from T_Tide).I am using the equation that all knows H(t) = Amplitude * cos ( t * harmonicSpeed + phase lag), I wrote my script in python. The output is not matching with the tide predicction (from the T_Tide file). As you know the construction is very simple but I am thinking that my problem is about the sampling interval, I really don´t know how to interpret it for this case, I wrote 1/24 due to the input time (for calculating in T_TIDE , hourly data), I am not sure about this.&lt;/p&gt;&#xA;&lt;p&gt;I share the harmonic constants file  from T_Tide and the tide predicction values file (hourly , which I want to reproduce). They are &lt;a href=&quot;https://github.com/feraxel/Harmonic-constans/commit/fb11b9ef9909b03e722978ccfa102fc7b9fd1f01#diff-09639ac17104196efd895598afe1af5234cbb5bcac39070e4a3d9133c611a4ea&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://github.com/feraxel/Harmonic-constans/commit/fb11b9ef9909b03e722978ccfa102fc7b9fd1f01#diff-09639ac17104196efd895598afe1af5234cbb5bcac39070e4a3d9133c611a4ea&lt;/a&gt;    and  &lt;a href=&quot;https://github.com/feraxel/Harmonic-constans/commit/1e46d1d416c49ef131005d8fa68775f9169c0270#diff-545b5ec39a1b72b56fa5e37c33afb30a3c3c39ba0e6fe1d583b4a1d77e9fc74a&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://github.com/feraxel/Harmonic-constans/commit/1e46d1d416c49ef131005d8fa68775f9169c0270#diff-545b5ec39a1b72b56fa5e37c33afb30a3c3c39ba0e6fe1d583b4a1d77e9fc74a&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;pre&gt;&lt;code&gt;os.chdir(r'directory') # change the file.txt directory&#xA;con =  pd.read_csv('harmonics_aca.txt',sep=' ') # We load the harmonic constants&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;h5&gt;We create a datetime vector for concatenate to the constructed tide&lt;/h5&gt;&#xA;&lt;pre&gt;&lt;code&gt;date = pd.date_range(start='01/02/2018 22:00:00', end='05/30/2022 15:00:00',freq='H') &#xA;datetime = pd.DataFrame({'Fecha':date})&#xA;&#xA;tide = 0 &#xA;H = [] # This vector save the tide for the t time &#xA;dt = 1/24 #####Sampling interval &#xA;for t in np.arange(0,len(fecha)*dt,dt):&#xA;    Am = con.iloc[i,2] # Harmonic constituent amplitude&#xA;    Ph = np.deg2rad(con.iloc[i,4]) # Harmonic constituent phase&#xA;    Fr = (con.iloc[i,1]*2*np.pi)  # Frecuency (1/Hours)*2*pi&#xA;    level = Am*np.cos(Fr*t - Ph)&#xA;    tide = tide+level&#xA;&#xA;H.append(tide)&#xA;tide = 0&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="27360" LastActivityDate="2022-12-27T18:54:06.210" Title="How to construct the tide signal from harmonic constituents?" Tags="|oceanography|ocean-currents|tides|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24687" PostTypeId="2" ParentId="24685" CreationDate="2022-12-27T18:54:06.210" Score="1" Body="&lt;p&gt;My recommendation is that you check the tidal prediction code provided with t_tide (t_predic). In there, you will find a piece of code like this:&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;ap=tidecon(:,1)/2.*exp(-i*tidecon(:,3)*pi/180);  am=conj(ap);&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;You can check that you are doing that part correctly up to there.&lt;/p&gt;&#xA;&lt;p&gt;The other important part is the astronomical nodal modulation correction. That is the difference in phase for your specific location. The code for that is given in t_vuf.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2022-12-27T18:54:06.210" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24696" PostTypeId="1" AcceptedAnswerId="24697" CreationDate="2022-12-28T01:44:13.647" Score="1" ViewCount="280" Body="&lt;p&gt;Let's consider 3 options for my position on Earth:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;North to tropic of Cancer&lt;/li&gt;&#xA;&lt;li&gt;Between tropic of Cancer and Capricorn&lt;/li&gt;&#xA;&lt;li&gt;South to tropic of Capricorn&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;If I take a compass and point it to the Sun, will it match next guess:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;North to tropic of Cancer -&amp;gt; the Sun will alway be to south&lt;/li&gt;&#xA;&lt;li&gt;Between tropic of Cancer and Capricorn -&amp;gt; the Sun may be both to north and south&lt;/li&gt;&#xA;&lt;li&gt;South to tropic of Capricorn -&amp;gt; the Sun will alway be to north&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="28215" LastActivityDate="2022-12-28T02:17:01.773" Title="Tropic of Cancer/Capricorn and sun position" Tags="|sun|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24697" PostTypeId="2" ParentId="24696" CreationDate="2022-12-28T02:17:01.773" Score="1" Body="&lt;p&gt;The short answer to your question is yes, you are correct in all instances.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropic_of_Capricorn&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tropic of Capricorn&lt;/a&gt; is the southernmost latitude where the Sun can be seen directly overhead, which occurs during the December solstice. Similarly the Tropic of Cancer is the northernmost latitude where the Sun can be seen directly overhead during the June solstice.&lt;/p&gt;&#xA;&lt;p&gt;Between the solstices the position of the Sun gradually varies so that at different times of the year the Sun will appear to be in the northern and southern parts of the sky.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2022-12-28T02:17:01.773" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24698" PostTypeId="2" ParentId="24023" CreationDate="2022-12-29T04:03:07.483" Score="1" Body="&lt;p&gt;You are correct that arc magmas are produced by melting of the mantle wedge above the subducting slab. In the case of felsic rocks in island arcs, a model I have not seen debunked is that these volcanoes typically produce early melts that are no more felsic than andesite. These andesites are then re-melted as the source for more differentiated dacites and rhyolites. This is supported by their geochemistry, which is more enriched relative to continental arc and rift rhyolites in 'typical' mafic elements like Ca and Al.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1440-1738.2010.00746.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://onlinelibrary.wiley.com/doi/abs/10.1111/j.1440-1738.2010.00746.x&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27389" LastActivityDate="2022-12-29T04:03:07.483" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24699" PostTypeId="1" CreationDate="2022-12-29T06:39:07.740" Score="2" ViewCount="28" Body="&lt;p&gt;So after a recent freeze in Texas the following overhang collapsed. Presumably water in existent cracks froze and made the cracks even bigger as the water expanded. Combined that with an increase in the weight of the overhang and it fell off.&lt;/p&gt;&#xA;&lt;p&gt;My question is...  let's say this freeze hadn't happened in Texas and that Texas wouldn't see any freezes for the next three years. As the springs behind the falls continues to produce water could travertine build up in the existent cracks form an adhesive, effectively &amp;quot;healing&amp;quot; the overhang from past freeze induced damage?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/z2BO9.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/z2BO9.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3157" LastEditorUserId="3157" LastEditDate="2022-12-29T13:19:36.953" LastActivityDate="2022-12-29T13:19:36.953" Title="Could travertine buildup seal up cracks in limestone?" Tags="|geology|mineralogy|limestone|cavern|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24700" PostTypeId="2" ParentId="24278" CreationDate="2022-12-29T09:23:34.097" Score="1" Body="&lt;p&gt;Volcanoes form mainly in plate boundaries as island arcs or volcanic arcs, but they can form too in &lt;a href=&quot;https://en.wikipedia.org/wiki/Hotspot_(geology)&quot; rel=&quot;nofollow noreferrer&quot;&gt;hotspots&lt;/a&gt;. These are hot points in the mantle that cross the crust producing volcanoes. An example are &lt;a href=&quot;https://en.wikipedia.org/wiki/Canary_Islands&quot; rel=&quot;nofollow noreferrer&quot;&gt;Canary Islands&lt;/a&gt;, that are inside the African Plate.&lt;/p&gt;&#xA;&lt;p&gt;Deep earthquake epicenters form too close to plate boundaries, but shallow earthquake epicenters can form far away from the plate boundary. This does not mean the origin of the earthquake is not a plate pushing another, it is just that the stress force vector can produce superficial faults to move far away from the boundary. An example is where I live, in Pamplona, Spain. From time to time we have 3-4 magnitude eartquakes because there is a fault close to our city, the Jaca-Pamplona fault. The force that cause the earthquakes is the African plate pushing the Iberian Peninsula, but the African plate is more than a thousand kilometers away.&lt;/p&gt;&#xA;&lt;p&gt;About mountains, Jean-Marie Prival answered you correctly. There are mountains that were formed in past collisions and have not been eroded completely. &lt;a href=&quot;https://www.iflscience.com/origins-australias-mountains-finally-explained-34529&quot; rel=&quot;nofollow noreferrer&quot;&gt;There are also mountains as Australia's mountains whose origin is different from a plate pushing the adjacent.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user28185" LastEditorDisplayName="user28185" LastEditDate="2022-12-29T14:29:59.303" LastActivityDate="2022-12-29T14:29:59.303" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24701" PostTypeId="2" ParentId="24682" CreationDate="2022-12-29T17:54:35.217" Score="1" Body="&lt;p&gt;I would love to flesh out a full answer on this but I am currently at work so for now I will give some other factoids that affect my answer. The graph provided seems to give a &lt;strong&gt;very&lt;/strong&gt; optimistic view of the effect that current policies will have.&lt;/p&gt;&#xA;&lt;p&gt;In short, no, I do not think there is a limit.&#xA;There are so many factors that contribute to and impact climate change; it is insane. To name a few:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the increased temperatures that we are currently seeing are melting the permafrost and glaciers. These areas are natural carbon sinks and currently hold large quantities of CO2 and methane. As they melt they release the stored methane, which is far worse for the atmosphere and environment than CO2.&lt;/li&gt;&#xA;&lt;li&gt;the oceans are a major carbon sink as phytoplankton, like trees, absorb CO2 and release oxygen. while many species of phytoplankton enjoy the increased water temperatures, they do not do as well with acidic waters. the increased acidity would subsequently kill off most phytoplankton&lt;/li&gt;&#xA;&lt;li&gt;old growth trees are also major carbon sinks. unfortunately, many of these trees have been cut down and the remaining forests are catching fire. Fires release CO2 into the atmosphere and kill off the trees that would pull the most carbon. less trees = more carbon = increased temps = more fires = less trees&lt;/li&gt;&#xA;&lt;li&gt;all of these factors directly impact the wildlife and the balances that make life possible on earth. without them, the balance is thrown and a domino effect occurs&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I see mentions of cloud cover which would minimally help, however, the increased methane creates holes in the atmosphere. the effects of this would outweigh the effects of cloud cover.&lt;/p&gt;&#xA;" OwnerUserId="28220" LastEditorUserId="28220" LastEditDate="2022-12-29T17:59:33.087" LastActivityDate="2022-12-29T17:59:33.087" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24702" PostTypeId="1" CreationDate="2022-12-30T06:22:55.423" Score="4" ViewCount="223" Body="&lt;p&gt;I read that the altitude of mountains is measured from the sea level. So, if the sea level rises significantly due to global warming, will the mountains and hills lose some of their altitudes and become less tall?&lt;/p&gt;&#xA;" OwnerUserId="28222" LastActivityDate="2023-01-03T20:28:18.647" Title="If the Sea level rises, will the mountains lose their height?" Tags="|atmosphere|geography|sea-level|mountains|altitude|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24704" PostTypeId="2" ParentId="24702" CreationDate="2022-12-30T08:10:57.580" Score="5" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;If the Sea level rises, will the mountains lose their height?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It depends on the mountain. Some mountains are rising due to &lt;a href=&quot;https://www.bbc.com/future/article/20220407-how-tall-will-mount-everest-get-before-it-stops-growing&quot; rel=&quot;noreferrer&quot;&gt;plate tectonics&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Post-glacial_rebound&quot; rel=&quot;noreferrer&quot;&gt;isostatic rebound&lt;/a&gt;. This can easily outpace sea level rise due to global warming. Some mountains are decreasing in height, not because of sea level rise but because of erosion. For example, the Appalachian mountains in the US and Canada are estimated to have once been as high as the Himalaya.&lt;/p&gt;&#xA;&lt;p&gt;But in general, the answer is yes.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2022-12-30T08:10:57.580" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24705" PostTypeId="1" CreationDate="2022-12-30T09:35:43.343" Score="7" ViewCount="85" Body="&lt;p&gt;Beaufort scale relates wind speed and wave height of the ocean surface. Does the wave height in the scale refer to significant wave height or mean wave height?&lt;/p&gt;&#xA;" OwnerUserId="28085" LastEditorUserId="111" LastEditDate="2023-01-01T18:15:36.910" LastActivityDate="2024-03-14T14:35:25.697" Title="Beaufort wind force measure" Tags="|oceanography|wind|waves|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24707" PostTypeId="2" ParentId="24452" CreationDate="2022-12-30T15:43:57.120" Score="3" Body="&lt;p&gt;Well, no, due to a host of reasons:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Remember that Theia was a Mars-sized impactor. This means that the impact would have produced too much heat, enough to decompose any diamonds that would have formed.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Even if diamonds were formed, they would have been later been swept downwards by tectonic activity, to be distributed finely across the Earth.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Theia's diamond deposits might have gone on to the Moon. But don't get excited about mining the Moon for diamonds. According to new theories, the Moon may have been formed in less than a few hours, compared to the millions-of-years time required for planet formation. Such a quick formation would have been very likely to decimate lunar diamonds down to just lunar graphite, or even just carbon dust, distributed finely inside the Moon, due to the intense heat being produced.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Theia's impact was so powerful that it has created &lt;a href=&quot;https://www.science.org/content/article/remains-impact-created-moon-may-lie-deep-within-earth#:%7E:text=Scientists%20have%20long%20agreed%20that,buried%20deep%20in%20Earth%27s%20mantle.&quot; rel=&quot;nofollow noreferrer&quot;&gt;two continent-sized reservoirs of magma&lt;/a&gt; deep inside Earth's mantle. This means no diamond formation, as they would have been melted down into molten carbon, or have been broken down into the mantle.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;No diamond mines for you, I am sorry.&lt;/p&gt;&#xA;" OwnerUserId="27863" LastActivityDate="2022-12-30T15:43:57.120" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24708" PostTypeId="2" ParentId="24526" CreationDate="2023-01-01T17:21:51.220" Score="3" Body="&lt;p&gt;I am most familiar with IGRF.  One simple way is to evaluate IGRF using only the dipole terms, and compare that to the field that you get from the quadrupole and higher order terms.&lt;/p&gt;&#xA;&lt;p&gt;There is publicly available software and coefficients of IGRF:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ncei.noaa.gov/products/international-geomagnetic-reference-field&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncei.noaa.gov/products/international-geomagnetic-reference-field&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;You could also try using WMM, which is nearly identical to IGRF:&#xA;&lt;a href=&quot;https://www.ngdc.noaa.gov/geomag/WMM/soft.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ngdc.noaa.gov/geomag/WMM/soft.shtml&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28233" LastActivityDate="2023-01-01T17:21:51.220" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24709" PostTypeId="1" CreationDate="2023-01-01T21:05:02.553" Score="2" ViewCount="105" Body="&lt;p&gt;For example, after the eruption of Mt. Pinatubo in 1991 according to &lt;a href=&quot;https://doi.org/10.1038/373399a0&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt;,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The introduction of large amounts of sulphuric acid aerosol into the stratosphere increases the planetary albedo (essentially the Earth's reflectivity of solar radiation) because these aerosol particles are efficient scatterers but only weak absorbers at solar wavelengths.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;...&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The changes in the Earth's albedo observed by ERBE resulted in a net cooling of approximately 8 W m-2 between 5°S and 5o N, with a net cooling of 4.3 W m-2 between 40° S and 40° N.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;What I'm interested in is &lt;em&gt;how&lt;/em&gt; exactly this cooling happens. Which is correct:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;the &lt;em&gt;atmosphere&lt;/em&gt; is experiencing a deficit of input energy, or&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;the &lt;em&gt;surface&lt;/em&gt; is experiencing a deficit of input energy, which is then communicated to the atmosphere by a decreases longwave surface emission&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;I suspect (2) is mostly correct, since about 75% of input shortwave solar radiation to the earth is absorbed by the surface, while only 25% by the atmosphere itself, according to ref [1] (and perhaps even less so by volcanic aerosols).&lt;/p&gt;&#xA;&lt;p&gt;If this is correct, then once the surface does communicate that energy deficit to the atmosphere, will it happen &lt;em&gt;locally&lt;/em&gt;? That is, will a slab of the atmosphere &lt;em&gt;nearest the surface&lt;/em&gt; be the first to experience a cooling rate?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;[1] Petty, G.W., 2006. A first course in atmospheric radiation, 2nd ed. ed. Madison, Wis: Sundog Pub.&lt;/p&gt;&#xA;" OwnerUserId="24997" LastActivityDate="2023-01-02T12:20:44.820" Title="How does a volcanic eruption cool the planet's surface?" Tags="|atmosphere|volcanology|atmospheric-radiation|radiative-transfer|aerosol|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24710" PostTypeId="1" AcceptedAnswerId="24713" CreationDate="2023-01-02T03:41:54.613" Score="5" ViewCount="134" Body="&lt;p&gt;According to &lt;a href=&quot;https://en.wikipedia.org/wiki/Indonesian_Throughflow&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;, Indonesian Throughflow passes Lombok Strait from north to south bringing water mass from the Pacific Ocean to the Indian Ocean.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/v3zFU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/v3zFU.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But when I the checked currents map on &lt;a href=&quot;https://www.windy.com/-8.773/115.725?currents,-8.673,115.611,10&quot; rel=&quot;nofollow noreferrer&quot;&gt;windy.com&lt;/a&gt; I found that current's direction is opposite - from south to north. So how can it be explained?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ec4p2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ec4p2.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28215" LastEditorUserId="2470" LastEditDate="2023-01-02T04:22:25.320" LastActivityDate="2023-01-03T14:10:48.403" Title="Indonesian Throughflow and currents map" Tags="|oceanography|ocean-currents|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24711" PostTypeId="2" ParentId="24709" CreationDate="2023-01-02T12:20:44.820" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;What I'm interested in is &lt;em&gt;how&lt;/em&gt; exactly this cooling happens. Which is correct:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;the &lt;em&gt;atmosphere&lt;/em&gt; is experiencing a deficit of input energy, or&lt;/li&gt;&#xA;&lt;li&gt;the &lt;em&gt;surface&lt;/em&gt; is experiencing a deficit of input energy, which is then communicated to the atmosphere by a decreases longwave surface emission&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Neither is correct. You are forgetting about reflection. Some of the incoming shortwave radiation is reflected back into space by the Earth's surface, and also by clouds and particles in the atmosphere. That reflected shortwave radiation does not cause warming. Increasing the reflectivity of the Earth increases the Earth's albedo and thereby decreases the amount of sunlight absorbed by the atmosphere or the surface.&lt;/p&gt;&#xA;&lt;p&gt;The aerosols emitted by volcanos increase the Earth's shortwave  reflectivity. The emissions from powerful volcanos can reach well into the stratosphere, thereby enabling those aerosols to stay in the atmosphere for a much longer time compared to aerosols that remain within the troposphere. Those stratospheric aerosols also help in the formation of stratospheric clouds, once again increasing the Earth's shortwave reflectivity.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-01-02T12:20:44.820" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24712" PostTypeId="1" CreationDate="2023-01-03T08:42:58.710" Score="1" ViewCount="34" Body="&lt;p&gt;The Intertropical Convergence Zone (ITCZ) is a band of low pressure that runs around the planet Earth; The Polar front is the Arctic band of low pressure that run around 60° N and south.&lt;/p&gt;&#xA;&lt;p&gt;Both those bands are subject to shifts and deformation due to the thermal differences and pressures and mostly are afected by the shape of the land they encounter.&lt;/p&gt;&#xA;&lt;p&gt;The Subtropical High Zone (STHZ) instead is the correspondent high pressure area that runs around 30 degrees north and south in general between the other two types of bands.&lt;/p&gt;&#xA;&lt;p&gt;The ITCZ is frequently bent due to pressure differences between highs;Likely so does the Polar front, but the behaviour of the STHZ... is what I'm trying to understand.&lt;/p&gt;&#xA;&lt;p&gt;How does the STHZ deform according to the changes on the polar front and ITCZ during the seasons, if it does at all?&lt;/p&gt;&#xA;" OwnerUserId="28237" LastEditorUserId="28237" LastEditDate="2023-01-03T10:42:01.970" LastActivityDate="2023-01-03T10:42:01.970" Title="How much shifts the Subtropical high zone from 30 degrees during seasons?" Tags="|climate|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24713" PostTypeId="2" ParentId="24710" CreationDate="2023-01-03T14:10:48.403" Score="6" Body="&lt;p&gt;The average conditions of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Indonesian_Throughflow&quot; rel=&quot;noreferrer&quot;&gt;Indonesian Throughflow&lt;/a&gt; (ITF) are well-represented by the top figure.&#xA;The transport varies significantly throughout the year. One main driver of the change in transport magnitude is the Monsoon. During the &lt;a href=&quot;https://en.wikipedia.org/wiki/Monsoon#Australia&quot; rel=&quot;noreferrer&quot;&gt;Indo-Australian Monsoon&lt;/a&gt; (November-February), westerly winds partly counteract the ITF transport, especially in the upper part of the water column. During the &lt;a href=&quot;https://en.wikipedia.org/wiki/Monsoon#Southwest_monsoon&quot; rel=&quot;noreferrer&quot;&gt;Southwest Monsoon&lt;/a&gt; (June-August), southeasterly winds over Indonesia drive additional flow through the ITF. In the transition months, downwelling favorable winds in the eastern Indian Ocean increase sea level in the southwest part of the ITF region, reducing the pressure gradient from the Pacific into the Indian Ocean and causing a minimum ITF transport. The sporadic eastward current in the Indian Ocean is referred to as the &lt;a href=&quot;https://doi.org/10.1126/science.181.4096.262&quot; rel=&quot;noreferrer&quot;&gt;Wyrtki jet&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;During times of reduced ITF transport, reversals of the ITF can occurred, especially in some of the smaller branches like the flow through Lombok Strait. The caused of these reversals is usually associated with specific weather systems. For example, &lt;a href=&quot;https://doi.org/10.1175/JPO-D-11-0120.1&quot; rel=&quot;noreferrer&quot;&gt;Shinoda et al. (2012)&lt;/a&gt; showed an episode of flow reversal during May 2004.  The development of a northward current anomaly can be seen in the sea surface height and current anomaly map.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DPEnz.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DPEnz.jpg&quot; alt=&quot;Shinoda et al. 2012 Figure 5d&quot; /&gt;&lt;/a&gt;&#xA;Sea Surface Height (shading; m) and upper-ocean (average over 50–250-m depths) velocity (vectors) anomalies during 9–30 May 2004 relative to the mean of April–June 2004. Source &lt;a href=&quot;https://doi.org/10.1175/JPO-D-11-0120.1&quot; rel=&quot;noreferrer&quot;&gt;Shinoda et al. (2012)&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2023-01-03T14:10:48.403" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24714" PostTypeId="2" ParentId="24702" CreationDate="2023-01-03T20:26:46.793" Score="6" Body="&lt;p&gt;It depends on which vertical datum your mountain elevation references.  If the elevation of the mountain is expressed in meters above mean sea level (or some other tidal datum) then yes.  If the elevation is expressed in meters above the geoid (a gravitational height) then no.  &lt;a href=&quot;https://vdatum.noaa.gov/docs/datums.html&quot; rel=&quot;noreferrer&quot;&gt;See this link&lt;/a&gt; for a tutorial on vertical datums.&lt;/p&gt;&#xA;" OwnerUserId="28239" LastEditorUserId="28239" LastEditDate="2023-01-03T20:28:18.647" LastActivityDate="2023-01-03T20:28:18.647" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24715" PostTypeId="1" CreationDate="2023-01-03T20:37:39.023" Score="5" ViewCount="99" Body="&lt;p&gt;I am trying to understand how melt water from snow in urban setting gets routed.&lt;/p&gt;&#xA;&lt;p&gt;I understand that for routing rain water, one can create grid and then determine the flow direction for each cell by using the D8 model. In the D8 model, first the slope for each of the 8 adjacent cells is calculated and then the direction of outflow corresponds to the direction of maximum slope. One can also compute the velocities with some approximations of the St. Venant equation.&lt;/p&gt;&#xA;&lt;p&gt;I was trying to understand if it makes sense to use this model when :&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Runoff is because of snow melt in the absence of rainfall.&lt;/li&gt;&#xA;&lt;li&gt;Runoff is generated because of a rain over snow event.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Using the D8 model would mean that, in both of these cases, the snow melts, water percolates down the snow pack, and when it touches the land or water mass, the routing happens according to the current slope values.&lt;/p&gt;&#xA;&lt;p&gt;Is this a reasonable way to characterize the meltwater flow?&lt;/p&gt;&#xA;&lt;p&gt;If not, is there any literature where this problem is solved using any alternate technique?&lt;/p&gt;&#xA;" OwnerUserId="27834" LastEditorUserId="27834" LastEditDate="2023-01-03T21:41:11.320" LastActivityDate="2023-01-03T21:41:11.320" Title="Simulating snow melt inundation in urban areas" Tags="|climate-change|glaciology|snow|flooding|runoff|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24716" PostTypeId="2" ParentId="24683" CreationDate="2023-01-03T20:44:46.227" Score="2" Body="&lt;p&gt;AVHRR does not capture green or blue so making an RGB image is not possible.  Your colorized example looks like a false-color representation of AVHRR NDVI images using a green to purple color band to me.  Migrate your question over to Geographic Information Systems Stack Exchange for help with QGIS and ArcGIS.  Best to make your data available for download if possible.&lt;/p&gt;&#xA;" OwnerUserId="28239" LastActivityDate="2023-01-03T20:44:46.227" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24719" PostTypeId="1" CreationDate="2023-01-05T07:09:25.677" Score="4" ViewCount="221" Body="&lt;p&gt;The image was taken about 5 p.m. in January, 2017.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BMZ7B.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BMZ7B.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28244" LastActivityDate="2023-01-05T15:18:04.993" Title="Does the cloud pattern in the image have a name?" Tags="|meteorology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24720" PostTypeId="2" ParentId="24719" CreationDate="2023-01-05T10:06:47.327" Score="3" Body="&lt;p&gt;It looks like a variation of a &lt;a href=&quot;https://en.wikipedia.org/wiki/Arcus_cloud#Roll_cloud&quot; rel=&quot;nofollow noreferrer&quot;&gt;roll cloud&lt;/a&gt;, where the rolls are smaller in diameter and more numerous.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-01-05T10:06:47.327" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24721" PostTypeId="2" ParentId="24683" CreationDate="2023-01-05T11:51:10.877" Score="6" Body="&lt;p&gt;You can use the Python library &lt;a href=&quot;https://satpy.readthedocs.io/en/stable/&quot; rel=&quot;nofollow noreferrer&quot;&gt;satpy&lt;/a&gt; to read AVHRR GAC data:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;from satpy import Scene&#xA;sc = Scene(filenames=[&amp;quot;NSS.GHRR.NJ.D95056.S1116.E1303.B0080506.GC&amp;quot;], reader=[&amp;quot;avhrr_l1b_gaclac&amp;quot;])&#xA;sc.load([&amp;quot;1&amp;quot;, &amp;quot;2&amp;quot;, &amp;quot;4&amp;quot;, &amp;quot;5&amp;quot;, &amp;quot;cloudtop&amp;quot;])&#xA;ls = sc.resample(&amp;quot;africa&amp;quot;)&#xA;ls.save_datasets()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;This will give you a GeoTIFF of the file resampled onto Africa, for channels 1, 2, 4, and 5.  It will also give you an RGB Satpy calls &amp;quot;cloudtop&amp;quot;, which is a combination of channels 3B, 4, and 5.  It will look very different from the true color RGB in your image.  You can load the GeoTIFF into standard GIS desktop software.  You can also write a variety of other output formats.  Check the Satpy documentation for details.&lt;/p&gt;&#xA;&lt;p&gt;For a full list of RGBs that you can generate with Satpy for AVHRR data, call &lt;code&gt;sc.available_composite_names()&lt;/code&gt; after you have created the Scene object.  None of the RGBs will look quite like true color, but &lt;code&gt;natural_color&lt;/code&gt; (if available) comes closest.  The &lt;code&gt;natural_color&lt;/code&gt; and &lt;code&gt;cloudtop&lt;/code&gt; RGBs depend on the availability of channels 3A or 3B, which are satellite and solar zenith angle dependent.&lt;/p&gt;&#xA;&lt;p&gt;There also exists a desktop tool called &lt;a href=&quot;https://sift.ssec.wisc.edu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;sift&lt;/a&gt; that can be used as a GUI to read any data Satpy can read, in case you are not comfortable with simple programming.  Support for polar satellites such as AVHRR was recently added to SIFT.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2023-09-25T06:57:10.670" LastActivityDate="2023-09-25T06:57:10.670" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24722" PostTypeId="1" CreationDate="2023-01-05T14:42:56.147" Score="1" ViewCount="31" Body="&lt;p&gt;I am using EDGAR V5 2015 emission files (edgar_v5_2015__0.1x0.1.nc) for WRF-Chem simulation. After giving the &lt;strong&gt;ncdump -v date,datesec edgar_v5_2015_CO_0.1x0.1.nc &amp;gt; ncdump.log&lt;/strong&gt; command, I learned that the date and datesec variables of the emission file are-&#xA;data:&lt;/p&gt;&#xA;&lt;p&gt;date = 20150101, 20150201, 20150301, 20150401, 20150501, 20150601, 20150701,&#xA;20150801, 20150901, 20151001, 20151101, 20151201 ;&lt;/p&gt;&#xA;&lt;p&gt;datesec = 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0 ;&#xA;}&#xA;Now I want to change the last date in the &lt;strong&gt;'date'&lt;/strong&gt; array from &lt;strong&gt;'20151201'&lt;/strong&gt; to &lt;strong&gt;'20151231'&lt;/strong&gt;. Can anyone please suggest how to do that? Is there any software available for that? I searched online and found a link to &lt;a href=&quot;https://stackoverflow.com/questions/59729526/how-to-edit-global-attributes-in-netcdf-file-with-nco&quot;&gt;https://stackoverflow.com/questions/59729526/how-to-edit-global-attributes-in-netcdf-file-with-nco&lt;/a&gt;, but there it was discussed how to edit global attributes in a netcdf file with NCO and the problem was different from mine. I have never used NCO, and I am having difficulties understanding what command I should use for this. Can anyone guide me in this regard? That will be very helpful for me. Thank you.&lt;/p&gt;&#xA;&lt;p&gt;With regards,&lt;/p&gt;&#xA;&lt;p&gt;Ankan&lt;/p&gt;&#xA;" OwnerUserId="28246" LastActivityDate="2023-01-05T14:42:56.147" Title="How to edit datesec array in edgar_v5_2015 emission files (netcdf format)?" Tags="|wrf-chem|emissions|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24723" PostTypeId="2" ParentId="24719" CreationDate="2023-01-05T15:18:04.993" Score="3" Body="&lt;p&gt;It could be a horizontal convective roll, also known as a &lt;a href=&quot;https://en.wikipedia.org/wiki/Horizontal_convective_rolls&quot; rel=&quot;nofollow noreferrer&quot;&gt;cloud street&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastActivityDate="2023-01-05T15:18:04.993" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24724" PostTypeId="1" CreationDate="2023-01-05T16:28:16.380" Score="6" ViewCount="118" Body="&lt;p&gt;First there was a once-a-century &lt;a href=&quot;https://oceanservice.noaa.gov/facts/bombogenesis.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;bomb cyclone&lt;/a&gt; 2000 miles wide that froze the entire Eastern US. &lt;a href=&quot;https://www.theguardian.com/us-news/2022/dec/23/us-weather-bomb-cyclone-us-christmas-latest&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gigantic US winter storm leaves millions without power and cancels holiday plans&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Then Europe had a record breaking heat dome. Here is a new article that explains a bit about the cause. &lt;a href=&quot;https://indianexpress.com/article/explained/explained-climate/what-is-causing-the-winter-heat-wave-in-europe-8359403/&quot; rel=&quot;nofollow noreferrer&quot;&gt;What is causing the winter heat wave in Europe?&lt;/a&gt; It says that heat domes are caused by high pressure zones of stagnant air.&lt;/p&gt;&#xA;&lt;p&gt;Two way bigger than normal events happened back to back. It makes me wonder if they are related? It sounds plausible that the Eastern US was cold because a lot of cold air from the arctic flowed south. If so, that air has to be replaced by warm air from the south flowing north. Did anything like this happen?&lt;/p&gt;&#xA;" OwnerUserId="5909" OwnerDisplayName="mmesser314" LastEditorUserId="6258" LastEditDate="2023-01-06T06:41:08.233" LastActivityDate="2023-01-06T06:41:08.233" Title="What has been going on in the atmosphere over the past couple weeks?" Tags="|meteorology|atmospheric-circulation|jet-stream|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24725" PostTypeId="1" CreationDate="2023-01-06T14:04:19.377" Score="0" ViewCount="105" Body="&lt;p&gt;We know that global warming has a component caused by greenhouse gases, but I was wondering how much of the heat is caused directly by burning fuel.&lt;/p&gt;&#xA;&lt;p&gt;I made this classification to explain what i am referring to.&lt;/p&gt;&#xA;&lt;p&gt;Global warming causes:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Natural causes&lt;/li&gt;&#xA;&lt;li&gt;Artificial causes&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Indirectly by releasing CO2 and other greenhouse gases&lt;/li&gt;&#xA;&lt;li&gt;Directly by burning fuel&lt;/li&gt;&#xA;&lt;li&gt;Other&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I guess the overall heat directly released by burning (not taking into account the CO2 released) is still relatively small.&lt;/p&gt;&#xA;&lt;p&gt;Second part. What if we finally achieve &amp;quot;almost free&amp;quot; energy (i.e. nuclear fusion)? What if we reach the point where anyone can make their own reactor on their backyard?&lt;/p&gt;&#xA;&lt;p&gt;For the sake of my argument, imagine 1 billion fusion reactors on earth, how much heat would that generate, and how that may affect temperature. At what point the temperature increase would be comparable to that caused by greenhouse gases?&lt;/p&gt;&#xA;&lt;p&gt;Anybody dare to do the numbers?&lt;/p&gt;&#xA;&lt;p&gt;Edit: Maybe I should have been more polite in my question. Anyway, the number i've taken from the responses is that this direct heat release is about 1% reponsible for global warming. So, as I understand it, we still have 1 or 2 orders of magnitude left for clean energy generation before it creates the same problem as greenhouse gases.&lt;/p&gt;&#xA;" OwnerUserId="28252" LastEditorUserId="28252" LastEditDate="2023-01-07T18:55:30.517" LastActivityDate="2023-01-07T18:55:30.517" Title="Global warming caused by direct energy release" Tags="|climate-change|" AnswerCount="1" CommentCount="4" ClosedDate="2023-01-07T18:50:40.420" ContentLicense="CC BY-SA 4.0" />
  <row Id="24726" PostTypeId="2" ParentId="24591" CreationDate="2023-01-06T17:03:49.200" Score="3" Body="&lt;p&gt;Try David Rothery's &amp;quot;Volcanoes, Earthquakes and Tsunamis&amp;quot; in the Teach Yourself series. Really well written and authoritative.&lt;/p&gt;&#xA;" OwnerUserId="28253" LastActivityDate="2023-01-06T17:03:49.200" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24727" PostTypeId="2" ParentId="24725" CreationDate="2023-01-06T21:28:42.800" Score="3" Body="&lt;p&gt;A 2009 study - &lt;em&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2008GL036465&quot; rel=&quot;nofollow noreferrer&quot;&gt;&amp;quot;Integrating anthropogenic heat flux with global climate models&amp;quot;&lt;/a&gt;&lt;/em&gt; by Mark Flanner found anthropogenic waste heat - which includes all energy used as well as wasted from non-renewable energy sources, ie energy from nuclear and fossil fuels - to be +0.028 W m−2 or about 1% of the climate forcing from enhanced greenhouse effect. It contributes to urban heat island, ie affects local areas at greater than the global average, and Flanner suggested it should be included in climate modeling to better show how much warming in urban areas.&lt;/p&gt;&#xA;&lt;p&gt;Another study &lt;em&gt;&lt;a href=&quot;https://www.jstage.jst.go.jp/article/jmsj/92A/0/92A_2014-A10/_pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Anthropogenic Heat Release: Estimation of Global Distribution and&#xA;Possible Climate Effect&lt;/a&gt;&lt;/em&gt; (2014) shows similar values.&lt;/p&gt;&#xA;&lt;p&gt;So there is a contribution to global warming from anthropogenic heat release but 99% of global warming is from other causes - with enhanced greenhouse from CO2 (from fossil fuel burning) being the single largest warming influence. And atmospheric aerosols (from fossil fuel burning) the largest cooling influence.&lt;/p&gt;&#xA;&lt;p&gt;I don't know if it included in the &amp;quot;Other Human Drivers&amp;quot; or not but this is from IPCC AR-6 SPM -&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iwCXT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iwCXT.png&quot; alt=&quot;Contributions to warming&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2023-01-06T21:28:42.800" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24728" PostTypeId="1" CreationDate="2023-01-07T12:06:12.743" Score="1" ViewCount="19" Body="&lt;p&gt;I have estimated actual evapotranspiration using the Penman-Monteith method and by using remote sensing data.&#xA;I have weekly evapotranspiration images. How to utilize this in irrigation scheduling? How to tell when a crop needs irrigation if only we have evapotranspiration data?&lt;/p&gt;&#xA;" OwnerUserId="28256" LastActivityDate="2023-01-07T12:06:12.743" Title="How to use actual evapotranspiration in irrigation scheduling?" Tags="|hydrology|remote-sensing|evapotranspiration|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24730" PostTypeId="1" CreationDate="2023-01-08T05:49:27.100" Score="2" ViewCount="67" Body="&lt;p&gt;Our group has built an Arduino-based device with an MPU6050 to act as our seismometer for our project, with the data being displayed on Amaseis. Our proctor demands that we quantitively assess its &amp;quot;effectiveness&amp;quot; through factors that we determined. We decided it is evaluated based on (this is subject to change depending on the answers to this question) proximity,  effective range, and accuracy.&lt;/p&gt;&#xA;&lt;p&gt;Please, how do we determine the proximity, effective range, and accuracy of our project, and what statistical tool (as it is required to use one) do we need in order to do so?&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;Note&lt;/strong&gt;&lt;/em&gt;: For accuracy, we've been planning to go to our local seismological institution (PHILVOLCS) to obtain waveform data, and we ought to compare it to our data. Although, this raises many questions such as:&lt;/p&gt;&#xA;&lt;p&gt;How do we quantitively compare two seismic data for accuracy, if they are taken from different locations? (and most probably different timeframes)&lt;/p&gt;&#xA;&lt;p&gt;As it is probably obvious, we are very unknowledgeable in this subject, and we would VERY much appreciate any help, feedback, or recommendation. As junior high students, we are very lost on how to proceed with this now.&lt;/p&gt;&#xA;" OwnerUserId="28259" LastActivityDate="2023-01-08T05:49:27.100" Title="How to quantitively compare two seismic waveform data?" Tags="|seismology|seismic|spectral-analysis|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24731" PostTypeId="1" CreationDate="2023-01-08T23:00:46.820" Score="1" ViewCount="35" Body="&lt;p&gt;If one considers the sum total of human heat emissions, especially over the last 3 centuries, the temperature increase over the time period does not seem to be commensurate. What gives? What self regulating mechanisms does earths atmosphere, and even biosphere, have which has ensured the temperature increase to be far lower than would be expected at a superficial level?&lt;/p&gt;&#xA;" OwnerUserId="28262" LastActivityDate="2023-01-08T23:00:46.820" Title="How has the earth's temperature stayed relatively stable despite all the heat released in the atmosphere by humans?" Tags="|climate|temperature|" AnswerCount="0" CommentCount="2" ClosedDate="2023-01-09T11:56:37.533" ContentLicense="CC BY-SA 4.0" />
  <row Id="24733" PostTypeId="1" CreationDate="2023-01-09T09:37:56.053" Score="1" ViewCount="257" Body="&lt;p&gt;I have netcdf (ERA5) file  (u and v component of wind and specific humidity) between years 1970-2022. Are there any package or script documentation about that?&lt;/p&gt;&#xA;" OwnerUserId="28264" LastActivityDate="2023-01-09T09:37:56.053" Title="How can I calculate integrated water vapor transport (IVT) in NCL, R or Python?" Tags="|netcdf|water-vapour|r|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24735" PostTypeId="1" CreationDate="2023-01-09T17:43:08.880" Score="4" ViewCount="40" Body="&lt;p&gt;I do apologize if this is the wrong place to ask this question. It's a rather simple question, but google gave me rather vague / random results, so I thought it might be better to ask somewhere like this place, where someone could give me a more solid answer&lt;/p&gt;&#xA;&lt;p&gt;My question is, which mineral, regardless of its nature (mined / lab made) has the highest index of refraction.&lt;/p&gt;&#xA;&lt;p&gt;I've heard there are ones higher than moissanite, which already has an excessively high IOR (nω=2.654 nε=2.967), but I wanted to know if there were any materials higher than that?&lt;/p&gt;&#xA;&lt;p&gt;For those curious as to why, I just wanted to find the highest refractive material to look at. I collect rare stones and minerals, and the higher the IOR, generally the prettier the faceted stones look in the end.&lt;/p&gt;&#xA;" OwnerUserId="28269" LastActivityDate="2023-01-09T17:43:08.880" Title="Which transparent mineral has the highest IOR? natural or lab made" Tags="|geology|light|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24736" PostTypeId="1" AcceptedAnswerId="24737" CreationDate="2023-01-10T03:36:17.840" Score="5" ViewCount="300" Body="&lt;p&gt;I opened windy.com for the California area and I found that the California current is displayed in the opposite way - from south to north. Is it affected by the recent cyclone or am I misunderstanding windy.com?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PGVvR.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PGVvR.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28215" LastEditorUserId="2470" LastEditDate="2023-01-10T06:45:43.400" LastActivityDate="2023-01-12T22:16:18.717" Title="Does the California cyclone change the California current?" Tags="|oceanography|ocean-currents|cyclone|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24737" PostTypeId="2" ParentId="24736" CreationDate="2023-01-10T09:35:06.817" Score="7" Body="&lt;p&gt;I'm certainly no oceanographer, but my initial thoughts were that most currents likely both vary and meander a lot.  And I'd expect much like the &lt;a href=&quot;https://apollo.nvu.vsc.edu/classes/met130/notes/chapter10/january_surface_press.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;semi-permanent atmospheric pressure systems&lt;/a&gt;, apart from the &lt;a href=&quot;https://www.windy.com/-Currents-currents?currents,27.994,-86.309,3&quot; rel=&quot;nofollow noreferrer&quot;&gt;very strongest currents&lt;/a&gt;, the transport is a longterm average rather than a near certainty at any instance.&lt;/p&gt;&#xA;&lt;p&gt;Seeing your run of questions on currents on Windy, I am a little interested what product Windy is showing.. whether it's surface ocean currents or maxima or mean or what.  I couldn't find any information on that.  Certainly wind will alter surface water flow, so I'd expect if Windy shows that it would be particularly prone to changes.  And even at a bit of depth, wind &lt;a href=&quot;https://www.conserve-energy-future.com/ocean-currents.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;can drive quite a few currents&lt;/a&gt;.  Since wind is far from static in direction, such currents also wouldn't tend to be.  And strong cyclones are far from atypical on the US Pacific coast, &lt;a href=&quot;https://drought.unl.edu/archive/climographs/sanfranciscoanc.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;particularly this time of year&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;But a quick Googling of the current off the west coast shows the change is more defined and typical:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xmiVg.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xmiVg.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;That's from the &lt;a href=&quot;https://en.wikipedia.org/wiki/California_Current&quot; rel=&quot;nofollow noreferrer&quot;&gt;California Current&lt;/a&gt; Wikipedia page.  Digging in further, the &lt;strong&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Davidson_Current&quot; rel=&quot;nofollow noreferrer&quot;&gt;Davidson Current&lt;/a&gt;&lt;/strong&gt; is&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;a coastal countercurrent of the Pacific Ocean running north along the&#xA;western coast of the United States from Baja California, Mexico to&#xA;northern Oregon, ending at about latitude 48°N&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;... it flows north rather than south and hugs the coastline. The&#xA;current is active year-round at 650 feet (200 meters) below sea level,&#xA;but surfaces during the winter months, generally from mid-November&#xA;through mid-February. In these months, northerly winds weaken and&#xA;are replaced to some extent by southwesterly winds.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;(note also that in your image, the flow still mainly has a small north-to-south component hundreds of miles offshore, which would tend to match the diagram)&lt;/p&gt;&#xA;&lt;p&gt;Finally, tying it all together, it looks like the paper &lt;a href=&quot;https://journals.ametsoc.org/view/journals/phoc/44/11/jpo-d-14-0012.1.xml?rskey=VrhTmA&amp;amp;result=3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Buoyancy-Driven Coastal Currents off Oregon during Fall and Winter (Mazzini et al, 2014)&lt;/a&gt; suggests that the winter south-to-north near-shore current may in part be caused by the increase in amount/scope of river discharges that are typically greater in the winter there (due to the increased precipitation).  Such that, while the water being discharged is colder than the ocean it flows into, its density difference (being freshwater) can cause it to flow north.&lt;/p&gt;&#xA;&lt;p&gt;If that's true, an exceptionally rainy winter along the US Pacific Coast should indeed mean a stronger northward winter current.&lt;/p&gt;&#xA;&lt;p&gt;But &lt;strong&gt;it looks like some degree of northward current right near the coast is quite common in the winter, so this appears to be normal.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2023-01-10T21:25:26.760" LastActivityDate="2023-01-10T21:25:26.760" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24738" PostTypeId="1" CreationDate="2023-01-10T14:35:36.640" Score="1" ViewCount="55" Body="&lt;p&gt;I came across this &lt;a href=&quot;https://study.com/academy/lesson/importance-of-the-tropic-of-cancer-the-tropic-of-capricorn.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;article&lt;/a&gt; and I would like to clarify a few moments:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;if you're located north of the Tropic of Cancer, the Sun will always&#xA;appear south of the zenith.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Does it mean if I am located north of the Tropic of Cancer and I point a compass to the Sun at noon, the Sun will alway be in south.&lt;/p&gt;&#xA;&lt;p&gt;And the same for the Tropic of Capricorn:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;if you're somewhere south of the Tropic of Capricorn, the Sun appears to be always north of the zenith&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;If I am located south of the Tropic of Capricorn and I point a compass to the Sun at noon, the Sun will alway be in north.&lt;/p&gt;&#xA;" OwnerUserId="28215" LastActivityDate="2023-01-10T14:35:36.640" Title="The Sun's location in noon and tropic of Cancer/Capricorn" Tags="|sun|" AnswerCount="0" CommentCount="3" ClosedDate="2023-01-11T04:25:32.557" ContentLicense="CC BY-SA 4.0" />
  <row Id="24739" PostTypeId="2" ParentId="24673" CreationDate="2023-01-10T15:46:01.163" Score="-1" Body="&lt;p&gt;The diamond mine suggest by &lt;a href=&quot;https://earthscience.stackexchange.com/questions/24673/what-is-this-warm-circle-in-the-middle-of-russia/24675#24675&quot;&gt;this accepted answer&lt;/a&gt; looks way too small.&lt;/p&gt;&#xA;&lt;p&gt;Checkout &lt;a href=&quot;https://earth.google.com/web/search/65.5857+N,+117.02636+E/@66.00929115,117.41656448,282.92292143a,42353.95740251d,35y,26.10045517h,0t,0r/data=CloaMBIqGRpR2ht8ZVBAIQt72uGvQV1AKhY2NS41ODU3IE4sIDExNy4wMjYzNiBFGAEgASImCiQJujzeo5VFUEAR230X9MFxS0AZ8RWc8zTiYUAhtClsyw3OXUA&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ozero Eyik&lt;/a&gt; instead.&lt;/p&gt;&#xA;" OwnerUserId="28282" LastEditorUserId="6298" LastEditDate="2023-01-10T21:28:02.693" LastActivityDate="2023-01-10T21:28:02.693" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24740" PostTypeId="1" CreationDate="2023-01-11T14:25:05.193" Score="8" ViewCount="847" Body="&lt;p&gt;Does the Moon, through factors like its location (if it is at an apsis i.e closest point or furthest point in its orbit) or some changes in density, affect earthquakes on the Earth?&lt;/p&gt;&#xA;&lt;p&gt;Earthquakes are a consequence of moving tectonic plates.  And when a tectonic plate slides under another one in a subduction zone or two plates crash into each other in convergent zones or two plates diverge, earthquakes can happen.  So I am wondering if the Moon's gravitational/tidal forces (e.g. &lt;a href=&quot;https://en.wikipedia.org/wiki/Tidal_heating&quot; rel=&quot;noreferrer&quot;&gt;tidal heating&lt;/a&gt;, which causes the interior of some celestial bodies to get hotter due to tidal friction) can cause perturbations on seismic activity which may influence the timing/strength of earthquakes? And how would I calculate those perturbations in the the seismic activity posed by the Moon?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.smithsonianmag.com/smart-news/does-moon-cause-earthquakes-study-says-no-1-180967896/&quot; rel=&quot;noreferrer&quot;&gt;This article&lt;/a&gt; states that the effect is small but I want to find out how much small the effect is.&lt;/p&gt;&#xA;" OwnerDisplayName="user27902" LastEditorUserId="6298" LastEditDate="2023-01-14T08:39:28.050" LastActivityDate="2023-01-15T10:35:09.673" Title="Does the Moon affect earthquakes?" Tags="|plate-tectonics|earthquakes|seismology|moon|" AnswerCount="1" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="24741" PostTypeId="1" CreationDate="2023-01-12T00:30:39.990" Score="3" ViewCount="165" Body="&lt;p&gt;&lt;strong&gt;When soil calcium is high:&lt;/strong&gt; High levels of soil calcium may be expected when there is substantial calcium carbonate bedrock from which the soil has weathered. Calcium levels can be high in agricultural settings from fertilizers. It's also not uncommon to find relatively high amounts in certain clays due to their heightened CEC.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;For example, &lt;a href=&quot;https://www.sustainablestables.com/post/soil-health-for-horse-pastures-part-5-calcium-magnesium&quot; rel=&quot;nofollow noreferrer&quot;&gt;this source&lt;/a&gt; (and others) suggest that calcium levels would be expected to be higher in clay vs sand (with some impact from pH):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Calcium in soil is generally correlated with the amount of sand versus clay in soil as well as soil pH.  Sandy soils tend to have calcium levels at or below 1000 lbs/acre, whereas high clay soils often have levels above 2,500 lbs/acre, Soils with a good pH level also tend to have plenty of soil Ca.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;My situation&lt;/strong&gt;: I've found relatively high levels (1200-2000 ppm) of soil calcium (measured by Mehlich III extraction; Mehlich 1984) from fairly non-acidic (pH = 5.5-6.5) alluvial &lt;em&gt;sandy&lt;/em&gt; soils.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;the soil type: &amp;quot;&lt;a href=&quot;https://casoilresource.lawr.ucdavis.edu/sde/?series=CARTECAY#osd&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cartecay&lt;/a&gt; and &lt;a href=&quot;https://casoilresource.lawr.ucdavis.edu/sde/?series=CHEWACLA#osd&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chewacla&lt;/a&gt; soils, 0 to 2 percent slopes, frequently flooded&amp;quot; (with perhaps mix of &amp;quot;White Store sandy loam, 10 to 25 percent slopes&amp;quot;)&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;the site is in a forested urban patch in central North Carolina (USA) and is neighbored by a small 1st order stream that occasionally floods the site after elevated post-storm drainage&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;For reference, nearby high-clay (more acidic) soils in higher topographic positions tended to have lower calcium levels between 200-1000 ppm.&lt;/p&gt;&#xA;&lt;p&gt;My question: &lt;strong&gt;what would be the source/cause of high calcium in sandy alluvial soils?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;What role does the nearing-neutral pH have?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Are there likely &amp;quot;natural&amp;quot; (e.g., geologic) sources of heightened calcium in this case, or is this likely a phenomenon due to high calcium effluent from upstream non-point pollution sources (e.g., golf course, hospital, parking lots)?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;em&gt;Update&lt;/em&gt;:&lt;/p&gt;&#xA;&lt;p&gt;I've also now noticed that the soil has many traits (e.g., high pH, Mg, Cu, Fe, Mn, and Zn) that could associate it as being a result of an &lt;strong&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Ultramafic_rock&quot; rel=&quot;nofollow noreferrer&quot;&gt;ultramafic&lt;/a&gt; &lt;a href=&quot;https://en.wikipedia.org/wiki/Layered_intrusion&quot; rel=&quot;nofollow noreferrer&quot;&gt;intrusion&lt;/a&gt;&lt;/strong&gt; (known to occur in this general region). However, I know that qualitatively speaking, ultramafic intrusions would have a high Mg/Ca ratio. My soil's ratios (for both A and B horizons):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;ppm_A: 350 ppm Mg / 1800 ppm Ca = 0.19&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;ppm_B: 315 ppm Mg / 1150 ppm Ca = 0.27&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;percent saturation A:  17% Mg / 50% Ca = 0.34&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;percent saturation B:  19% Mg / 38% Ca = 0.5&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I'm not sure what constitutes &amp;quot;high&amp;quot; as I'm unsure of a baseline (i.e., is high much greater than a ratio of 1 or simply greater than a ratio of 0?).&lt;/p&gt;&#xA;&lt;p&gt;Is it possible that this hypothesis holds any weight??&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;other issues: do ultramafic intrusions result in sandy alluvial soils?, &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/0016703767900993&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; suggests there'd be high Na, of which my soil has very low amounts (1/50th of which the linked source suggests).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="7536" LastEditorUserId="7536" LastEditDate="2023-01-12T19:54:14.753" LastActivityDate="2023-01-12T19:54:14.753" Title="Causes of high calcium levels in sandy alluvial soils" Tags="|geochemistry|soil|rivers|soil-science|watershed|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24742" PostTypeId="2" ParentId="24673" CreationDate="2023-01-12T03:38:07.370" Score="3" Body="&lt;p&gt;Personally, I believe it to be an interpolation artifact. I have been looking at the land surface temperature (LST) from multiple satellites that have a resolution of 1km and there is nothing that I can see in that area.&lt;/p&gt;&#xA;&lt;p&gt;Here is an example from MODIS Terra satellite&#xA;&lt;a href=&quot;https://i.stack.imgur.com/r4VvO.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/r4VvO.jpg&quot; alt=&quot;MODIS LST&quot; /&gt;&lt;/a&gt; Source &lt;a href=&quot;https://neo.gsfc.nasa.gov/view.php?datasetId=MOD_LSTD_D&amp;amp;date=2022-11-09&quot; rel=&quot;nofollow noreferrer&quot;&gt;MODIS&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;You can explore all their data directly from the &lt;a href=&quot;https://neo.gsfc.nasa.gov/view.php?datasetId=MOD_LSTD_D&amp;amp;date=2022-11-09&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA Earth Observations&lt;/a&gt; site and you can play with the data there.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2023-01-12T03:38:07.370" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24743" PostTypeId="2" ParentId="24740" CreationDate="2023-01-12T08:52:49.607" Score="4" Body="&lt;h1&gt;Actually, yes, but indirectly&lt;/h1&gt;&#xA;&lt;p&gt;Well, the tidal forces produced by the Moon's gravity are not enough to distort the Earth's crust enough to produce any significant displacements of the crust, and produce earthquakes. The only significant effect would be producing tides on the ocean. Remember the crust is rigid, whereas water is not.&lt;/p&gt;&#xA;&lt;p&gt;However, the Moon's gravity does warm up the Earth's core up to some degree, due to the continuous squeezing and stretching of the Earth (Most of the internal heat comes from radioactive decay and heat from the formation of the planet). It is this warmth, that drives tectonic plates, and thus ultimately, earthquakes.&lt;/p&gt;&#xA;&lt;p&gt;EDIT: Crustal tides are indeed produced by the Moon's gravity. In fact, this effect causes New York to rise and sink by 14 inches in a day. But this effect is too smooth. You cannot perceive this effect with the naked eye. Crustal tides are not violent, rapid events. They occur gradually throughout the day. On the other hand, Earthquakes are produced by many reasons, most common being the sudden release of pressure and energy by tectonic plates, in just a fraction of a second. This sudden release of energy triggers vibrations in the plates, which we call Earthquakes.&lt;/p&gt;&#xA;&lt;p&gt;Lunar gravity is simply not strong enough to trigger massive and rapid disturbances in the crust to create Earthquakes of sufficient magnitude. Even if it did happen, it would mostly be restricted to Magnitude 0-2 on the Modified Mercalli Scale, which can barely be noticeable to humans.&lt;/p&gt;&#xA;&lt;p&gt;The only place where gravity/tidal forces can trigger powerful earthquakes would be a moon of Jupiter, Io. Io's interior, which is already under massive stresses from Jupiter's gravity, can find itself further distorted by combined gravitational forces from Ganymede, Callisto and Europa, which can trigger massive earthquakes (Ioquakes?) and of course, volcanoes.&lt;/p&gt;&#xA;" OwnerUserId="27863" LastEditorUserId="27863" LastEditDate="2023-01-15T10:35:09.673" LastActivityDate="2023-01-15T10:35:09.673" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="24744" PostTypeId="1" CreationDate="2023-01-12T12:21:05.083" Score="1" ViewCount="20" Body="&lt;p&gt;I am looking for books or reviews on liquid-gas phase transition, going beyond the basics covered in statistical mechanics texts (Ehrenfest classification, mainly van-der-Waals equation).&lt;/p&gt;&#xA;&lt;p&gt;Most books on phase transitions seem to dismiss the subject as less interesting than the second order phase transitions, but perhaps there is a more complete chapter somewhere?&lt;/p&gt;&#xA;&lt;p&gt;Another possibility is chemistry texts or texts devoted to more specific problems, like atmospheric science or water.&lt;/p&gt;&#xA;&lt;p&gt;Related: &lt;a href=&quot;https://physics.stackexchange.com/q/409610/247642&quot;&gt;Phase Transitions (Statistical Mechanics) Book Recommendation&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20239" LastActivityDate="2023-01-12T12:21:05.083" Title="Liquid-gas phase transitions" Tags="|literature-request|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24745" PostTypeId="1" CreationDate="2023-01-12T20:01:24.530" Score="4" ViewCount="115" Body="&lt;p&gt;How can you best represent strike data on a rose diagram? Is it okay to plot only the strike?&lt;/p&gt;&#xA;" OwnerUserId="28295" LastEditorDisplayName="user28185" LastEditDate="2023-01-13T18:45:42.913" LastActivityDate="2023-01-14T07:12:28.883" Title="Representing strike lines in rose diagrams" Tags="|geology|structural-geology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24747" PostTypeId="1" AcceptedAnswerId="24752" CreationDate="2023-01-12T22:32:43.427" Score="3" ViewCount="110" Body="&lt;p&gt;I am trying to understand how to obtain ELA using Accumulation area ratio method. My understanding is:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Accumulation area/ ablation area is assumed to be constant.&lt;/li&gt;&#xA;&lt;li&gt;Empirical data of long term annual mass balance, Bn and corresponding AAR is needed to obtain steady state AAR of a particular glacier.(For the graph of AAR vs Bn, corresponding AAR value for Bn = 0)&lt;/li&gt;&#xA;&lt;li&gt;Total area of the glacier should be known.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Now, with AARo and total glacier area, how do I obtain ELA?&lt;/p&gt;&#xA;" OwnerUserId="28184" LastEditorUserId="6" LastEditDate="2023-01-13T08:41:14.777" LastActivityDate="2023-01-13T21:24:37.077" Title="Obtaining ELA from AAR method" Tags="|glaciology|geomorphology|snow|altitude|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24748" PostTypeId="2" ParentId="24745" CreationDate="2023-01-13T09:55:04.360" Score="4" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;How can you best represent strike data on a rose diagram?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In &lt;a href=&quot;https://en.wikipedia.org/wiki/Wind_rose&quot; rel=&quot;nofollow noreferrer&quot;&gt;rose diagrams&lt;/a&gt; lines are represented and strike is a line so I don't see the problem: &lt;em&gt;diagrams don't bite!&lt;/em&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Is it okay to plot only the strike?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Why not, if the rose diagram helps in the description and there is not a technical impediment?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TcCf8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TcCf8.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.usna.edu/Users/oceano/pguth/md_help/html/rose_diagram.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But... what about representing extra data besides the set of strikes?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2scpN.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2scpN.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.researchgate.net/figure/Rose-diagrams-The-rose-diagrams-for-the-average-strike-of-the-reactivated-fracture-zones_fig3_312070347&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;You are not going to be the first one plotting lines in a circular diagram of frequencies, but you should consider before publishing: &lt;em&gt;does the diagram add sense to my report?&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user28185" LastEditorDisplayName="user28185" LastEditDate="2023-01-14T07:12:28.883" LastActivityDate="2023-01-14T07:12:28.883" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24751" PostTypeId="1" CreationDate="2023-01-13T17:21:09.140" Score="4" ViewCount="30" Body="&lt;p&gt;I've read from various University Extension sites (e.g., &lt;a href=&quot;https://ag.umass.edu/vegetable/fact-sheets/boron-deficiency&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;https://www.canr.msu.edu/news/why_does_boron_show_up_on_my_soil_test_report&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;) that &lt;strong&gt;boron levels would be deficient in sandy soils with low organic matter&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;This would suggest that boron levels would be &lt;em&gt;higher&lt;/em&gt; in non-sandy soils with &lt;em&gt;high&lt;/em&gt; organic matter (OM) levels.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;However, in a series of upland forest patches in central NC with clayey (low sand) soils with substantial OM, &lt;strong&gt;I've found the opposite to be true: Soil boron-levels in these low sand/high OM plots were regionally amongst the lowest levels measured&lt;/strong&gt; (&amp;lt;0.2 ppm; more than 4x lower than nearby sandy soils with low OM).&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;This seems to contradict the above stated trend from extension websites.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Question: What would cause this trend? &lt;strong&gt;What would cause boron levels to be so deficient in clayey (non sandy) high OM soil?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Other information about sites:&lt;/em&gt; relatively dry, high topographic position and exposure, acidic (pH &amp;lt; 6) soil, high {K, Al, S} in soil. Vegetation = mid-to-late successional mixed hardwood/oak-hickory forests with relatively open understory due to deer overbrowse.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;Note: soil methods: Mehlich III extraction for plant nutrients; loss-on-ignition method for OM. &lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="7536" LastActivityDate="2023-01-13T17:21:09.140" Title="Reason for finding low boron levels in clayey soil with high organic matter?" Tags="|geochemistry|soil|soil-science|nutrient-cycles|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24752" PostTypeId="2" ParentId="24747" CreationDate="2023-01-13T21:24:37.077" Score="2" Body="&lt;p&gt;The ELA (Equilibrium Altitude) is related to the AAR (Accumulationa Area relationship). But before exploring the realationship we must establish what these entities mean.&lt;/p&gt;&#xA;&lt;p&gt;First, AAR, relates the area occupied by the accumulation area to the total area by the glacier. The accumulation area is by definition the area showing a surplus of mass by the end of the season. This means that the snow falling during the year survives the melt season. Hence we relate the total area of the glacier to the area experiencing a net surplus of mass at the end of the mass balance year to yield a percentage value indicating what percentage of the glacier is experiencing a surplus.&lt;/p&gt;&#xA;&lt;p&gt;The area experiencing surplus of mass is defined as the accumulation area and the area experiencing a deficit of mass is defined as the ablation area. On any glacier, the line separating the areas of surplus and deficit of mass is defined as the equilibrium line. This means that the total mass gain equals the mass loss along this line and on each side there will be a net gain or loss of mass.&lt;/p&gt;&#xA;&lt;p&gt;The equilibrium line will ideally divide the glacier into two areas experiencing net total mass loss and mass gain, respectively. Because mass gain is commonly occuring at higher altitude and mass losses occuring at lower altitudes due to snow distribution and the decrease of temperature and hence melting with altitude, areas of mass loss occur at lower elevation while areas of mass gain occurs at higher elevation.&lt;/p&gt;&#xA;&lt;p&gt;The equilibrium line altidude (ELA) is usuually a calculated entity dependent on where the net balance curve of the glacier crosses the zero balance, i.e. the altitude where the glacier net balance changes sign or goes from loss to gain or &lt;em&gt;vice versa&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Based on this we can see that ELA and AAR are related but calculated in different ways from the same original data. AAR is simply the relationship between the area of positive and negative mass change whereas the ELA is the altitude where the elevation dependent mass balance turns from postive to negative or &lt;em&gt;vice versa&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;References&lt;/p&gt;&#xA;&lt;p&gt;[Cogley et al., 2011] [1]&lt;/p&gt;&#xA;&lt;p&gt;[Kaser et al. 2003] [2]&lt;/p&gt;&#xA;&lt;p&gt;[1] &lt;a href=&quot;https://wgms.ch/downloads/Cogley_etal_2011.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://wgms.ch/downloads/Cogley_etal_2011.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;[2] &lt;a href=&quot;https://unesdoc.unesco.org/ark:/48223/pf0000129593.locale=en&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://unesdoc.unesco.org/ark:/48223/pf0000129593.locale=en&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2023-01-13T21:24:37.077" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24755" PostTypeId="2" ParentId="24053" CreationDate="2023-01-15T15:58:41.817" Score="-2" Body="&lt;p&gt;The Northern Hemisphere is warmer than the Southern Hemisphere in part because of northward cross-equatorial ocean heat transport. &lt;a href=&quot;http://ocp.ldeo.columbia.edu/res/div/ocp/pub/seager/Kang_Seager_subm.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://ocp.ldeo.columbia.edu/res/div/ocp/pub/seager/Kang_Seager_subm.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It is considered that the northern hemisphere has more land mass while the southern hemisphere has more ocean and therefore varies in the rate of warming.&#xA;&lt;a href=&quot;https://atmosphere.copernicus.eu/carbon-dioxide-levels-are-rising-it-really-simple&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://atmosphere.copernicus.eu/carbon-dioxide-levels-are-rising-it-really-simple&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28310" LastEditorUserId="28310" LastEditDate="2023-01-15T15:59:26.233" LastActivityDate="2023-01-15T15:59:26.233" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24757" PostTypeId="1" CreationDate="2023-01-16T16:57:13.583" Score="1" ViewCount="29" Body="&lt;p&gt;I had this thought the other day, not as a good idea but as a thought experiment. What would be the effects of putting some kind of sun-blocking satellite/s at the &lt;a href=&quot;https://solarsystem.nasa.gov/resources/754/what-is-a-lagrange-point/&quot; rel=&quot;nofollow noreferrer&quot;&gt;L1 Lagrange point&lt;/a&gt; which blocked 90% of sunlight above a latitude so that 1/4 of the earth received the reduced sunlight at any part of the year?&lt;/p&gt;&#xA;&lt;p&gt;IIUC the &amp;quot;line&amp;quot; would move throughout the year due to the tilt of the earth, shifting between northern and southern hemispheres.&lt;/p&gt;&#xA;&lt;p&gt;Obvious changes:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;radically reduced temperatures in the northern and southern hemispheres&lt;/li&gt;&#xA;&lt;li&gt;at least moderately (?) reduced temperatures on the whole earth&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Less obvious would be the near-immediate radical changes to weather patterns, likely resulting in chaos for many years but eventually stabilizing to some form of steady state. What would the new steady-state look like?&lt;/p&gt;&#xA;" OwnerUserId="28314" LastActivityDate="2023-01-16T16:57:13.583" Title="What would the effect on the weather be if the southern and northern latitudes received 90% less sunlight?" Tags="|meteorology|geoengineering|" AnswerCount="0" CommentCount="8" ClosedDate="2023-01-20T17:53:27.687" ContentLicense="CC BY-SA 4.0" />
  <row Id="24758" PostTypeId="2" ParentId="15379" CreationDate="2023-01-17T01:59:42.473" Score="1" Body="&lt;p&gt;If you want to quantify how much water vapor you can have in dry air for a given temperature and relative humidity, you can use what ASHRAE (American Society of Heating, Refrigerating and Air-Conditioning Engineers) terms a psychrometric chart. The theory behind this chart can be found in numerous Engineering Thermodynamics texts. For example, &amp;quot;Engineering Thermodynamics&amp;quot; 2nd ed., Glen E. Myers, AMCHT Publications, 2007. Below is a copy of one of the pages in this text. The vertical axis in the plot is humidity ratio (pounds of water vapor/pound of dry air). For a given relative humidity, the humidity ratio is monotonic in temperature. The humidity ratio rise with temperature is much more rapid than linear.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Jo0yV.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Jo0yV.jpg&quot; alt=&quot;psychometric chart&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28317" LastActivityDate="2023-01-17T01:59:42.473" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24759" PostTypeId="1" CreationDate="2023-01-17T09:37:17.390" Score="3" ViewCount="113" Body="&lt;p&gt;While reading the &lt;a href=&quot;https://gimms.gsfc.nasa.gov/SMOS/SMAP/L04/&quot; rel=&quot;nofollow noreferrer&quot;&gt;SMAP&lt;/a&gt; data (grib format) using xarray with cfgrib as engine, the variable is shown as &lt;code&gt;unknown&lt;/code&gt; and the longitude of the data has a value of around 539 which shouldn't be possible. I assume the variable being identified as `Unknown may be due to the missing grib table for the SMAP data. Summary of data read using xarray is given below:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;&amp;lt;xarray.Dataset&amp;gt;&#xA;Dimensions:     (latitude: 1920, longitude: 2560)&#xA;&#xA;Coordinates:&#xA;    time        datetime64[ns] ...&#xA;    step        timedelta64[ns] ...&#xA;    level       float64 ...&#xA;  * latitude    (latitude) float64 -89.95 -89.86 -89.77 ... 89.77 89.86 89.95&#xA;  * longitude   (longitude) float64 -179.9 -179.8 -179.6 ... 179.6 179.8 539.9&#xA;    valid_time  datetime64[ns] ...&#xA;Data variables:&#xA;    unknown     (latitude, longitude) float32 ...&#xA;Attributes:&#xA;    GRIB_edition:            2&#xA;    GRIB_centre:             consensus&#xA;    GRIB_centreDescription:  Consensus&#xA;    GRIB_subCentre:          65535&#xA;    Conventions:             CF-1.7&#xA;    institution:             Consensus&#xA;    history:                 2023-01-17T14:45 GRIB to CDM+CF via cfgrib-0.9.1...&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;The output of wgrib2 is given below:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;** WARNING input Code Table 4.3 = 255 (undefined) for 20150402_20150404_anom1.grb2 **&#xA;1:0:d=1970010100:var discipline=1 master_table=2 parmcat=255 parm=255:reserved:anl:&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="28318" LastActivityDate="2023-01-17T14:29:07.967" Title="Read SMAP grib data using python" Tags="|python|soil-moisture|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24760" PostTypeId="2" ParentId="24759" CreationDate="2023-01-17T14:29:07.967" Score="3" Body="&lt;p&gt;It seems like the GRIB format is being used to distribute the data (probably for storage, ease of processing?), while satellite SMAP doesn't fit under the GRIB standard (see available parameters supported in the GRIB standard &lt;a href=&quot;https://www.nco.ncep.noaa.gov/pmb/docs/grib2/grib2_doc/grib2_table4-1.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;). This is why the input code is 255 (i.e. &amp;quot;missing&amp;quot;).&lt;/p&gt;&#xA;&lt;p&gt;I downloaded the file &lt;code&gt;20150402_20150404_anom1.grb2&lt;/code&gt; and opened in Python using xarray 0.18.2 with cfgrib 0.9.10.1. I cannot see the anomalous longitude.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;&amp;lt;xarray.Dataset&amp;gt;&#xA;Dimensions:     (latitude: 1920, longitude: 2560)&#xA;Coordinates:&#xA;    time        datetime64[ns] 1970-01-01&#xA;    step        timedelta64[ns] 00:00:00&#xA;    level       float64 0.0&#xA;  * latitude    (latitude) float64 -89.95 -89.86 -89.77 ... 89.77 89.86 89.95&#xA;  * longitude   (longitude) float64 -179.9 -179.8 -179.6 ... 179.6 179.8 179.9&#xA;    valid_time  datetime64[ns] 1970-01-01&#xA;Data variables:&#xA;    unknown     (latitude, longitude) float32 nan nan nan nan ... nan nan nan&#xA;Attributes:&#xA;    GRIB_edition:            2&#xA;    GRIB_centre:             consensus&#xA;    GRIB_centreDescription:  Consensus&#xA;    GRIB_subCentre:          65535&#xA;    Conventions:             CF-1.7&#xA;    institution:             Consensus&#xA;    history:                 2023-01-17T15:53 GRIB to CDM+CF via cfgrib-0.9.1...&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;You can read and process the data in Python in any case using &lt;code&gt;'unknown'&lt;/code&gt; as the variable name:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;ds = xr.open_dataset(...)&#xA;smap = ds.variables['unknown']&#xA;lon = ds.variables['longitude']&#xA;lat = ds.variables['latitude']&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OYe7f.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OYe7f.jpg&quot; alt=&quot;2&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18907" LastActivityDate="2023-01-17T14:29:07.967" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24761" PostTypeId="1" CreationDate="2023-01-17T14:55:22.753" Score="2" ViewCount="24" Body="&lt;p&gt;In Google Maps the floor of the Atlantic Ocean is shown as having much transverse &amp;quot;scarring&amp;quot;. What are these crust formations? They're ~2,000 miles long. What caused them?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NQsw9.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NQsw9.png&quot; alt=&quot;Atlantic Ocean floor in Google Maps&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28321" LastActivityDate="2023-01-17T14:55:22.753" Title="What caused the transverse &quot;scarring&quot; of the Atlantic Ocean floor" Tags="|oceanic-crust|" AnswerCount="0" CommentCount="1" ClosedDate="2023-01-17T20:28:08.240" ContentLicense="CC BY-SA 4.0" />
  <row Id="24762" PostTypeId="2" ParentId="18131" CreationDate="2023-01-17T17:55:57.590" Score="-2" Body="&lt;p&gt;First, our current ongoing Pleistocene/Quaternary Ice Age has not ended. It is in its many times repeated interglacial phase. The latest of at least thirty interglacials. Our current interglacial is called the Holocene. In this interglacial, we invented agriculture and civilization. The ongoing Pleistocene/Quaternary Ice Age is characterized by a regular, cyclical 12°C warming and cooling every one hundred thousand years. A temperature range so great that during the 8°C coldest glacial phases (typically lasting about 85,000 years), ice sheets thousands of feet thick advance to latitudes as far south as NYC. And during the warmest 4°C interglacial phases, like our current Holocene, ice sheets recede to their current polar latitudes. The cause of this huge natural variation in earth's temperature is Milankovitch Eccentricity. The natural variation in the shape of earth's orbit from near circular (like today) to significantly more oblong. As it was fifty thousand years ago, and will be fifty thousand years from today. That more oblong ellipsoidal orbit has a natural decrease in the earth's annual insolation of 20-30%! &lt;a href=&quot;https://geol105.sitehost.iu.edu/images/gaia_chapter_4/milankovitch.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://geol105.sitehost.iu.edu/images/gaia_chapter_4/milankovitch.htm&lt;/a&gt; And during interglacial phases there is a shorter nine hundred year 4°C &amp;quot;Eddy Cycle&amp;quot; as studied by Dr. Judith Curry. The latest iteration began in the &amp;quot;Little Ice Age&amp;quot; of the 1600s. When they could ice skate on the Thames. Londoners haven't been able to do that for 200 years! Here's Dr. Curry on the Medieval Warm Period, the Roman Warm Period, the Minoan Warm Period, all warmer than we are today... &lt;a href=&quot;https://wattsupwiththat.com/2016/07/31/a-warm-period-by-any-other-name-the-climatic-optimum/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://wattsupwiththat.com/2016/07/31/a-warm-period-by-any-other-name-the-climatic-optimum/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28322" LastActivityDate="2023-01-17T17:55:57.590" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24763" PostTypeId="2" ParentId="18105" CreationDate="2023-01-17T18:48:25.863" Score="-4" Body="&lt;p&gt;Life began near alkaline warm water vents about 3.8 billion years ago. It was carbon-based right from the beginning. Composed entirely of little carbon (lipid) sacks of water we call cells. That carbon all came from CO2. CO2 atmospheric concentrations then were about twenty times those of today (about 8,000-10,000ppm.) And there is fifty times more CO2 dissolved in water than there is in the atmosphere! A short (in geological timeframes) 200 million years later photosynthesis evolved. Photosynthesis is nearly as old as life itself. And arguably the most important metabolism in life on earth. Photosynthesis freed living organisms' dependence on warm water vent energy and allowed life to spread anywhere there is sunlight! Its formula is sunlight plus CO2 plus H2O with the green enzyme chlorophyll converts sunlight energy into living high energy sugar bonds, brings the carbon (2nd most abundant element in living species) into our carbon-based life on earth, gives the &amp;quot;environment&amp;quot; its green colour. All of life's carbon, all of life's energy, and as a bonus every molecule of the oxygen we breathe! There is nothing more important to life on earth. And life-essential CO2 has been dangerously and inexorably declining since life's birth to within 30ppm of the beginning of the death of all things. Recycling more CO2 by using fossil fuels has been the greatest contribution to the sustainability of life on earth that human beings have ever done. It delays the death of all things from a lack of CO2. Here's Dr. Patrick Moore, co-founder of Greenpeace. Thank you PragerU... &lt;a href=&quot;https://www.youtube.com/watch?v=WDWEjSDYfxc&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=WDWEjSDYfxc&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28322" LastActivityDate="2023-01-17T18:48:25.863" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24764" PostTypeId="1" AcceptedAnswerId="24802" CreationDate="2023-01-17T20:16:28.810" Score="7" ViewCount="298" Body="&lt;p&gt;The explanations for why the Earth's core is hot I found on the internet included:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;leftover energy from the Earth's formation&lt;/li&gt;&#xA;&lt;li&gt;radioactivity of the elements inside the core&lt;/li&gt;&#xA;&lt;li&gt;friction between the core and the more outer layers which spin more fast&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;However, I haven't found any indications that would point to the high pressure being a factor. So does the large pressure inside the Earth's core contribute to its high temperature?&lt;/p&gt;&#xA;&lt;p&gt;EDIT: If it doesn't, I'm interested in why. If pressure is the kinetic energy of the molecules, I'd expect higher pressure to cause higher temperatures, similarly to the &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Ideal_gas_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;ideal gas law&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5016" LastEditorUserId="5016" LastEditDate="2023-01-26T10:40:49.933" LastActivityDate="2023-01-27T15:35:51.147" Title="Does the high pressure inside the Earth's core contribute to its high temperature?" Tags="|geology|geophysics|core|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24765" PostTypeId="2" ParentId="24764" CreationDate="2023-01-18T16:27:01.750" Score="2" Body="&lt;p&gt;First off, I'll look at the explanations you have found.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;leftover energy from the Earth's formation&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is typically split into two parts, the energy from the collisions that formed the Earth, and the energy from the differentiation of the proto-earth into a core, mantle and crust.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;radioactivity of the elements inside the core&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is highly debated. Geophysicists and geochemists agree to disagree. Geophysicists want a rather high heat flux across the core-mantle boundary because their geodynamo models (which aren't quite perfect) demand it. Geochemists say otherwise. The problem is that the three elements (uranium, thorium, and potassium) that provide four long-lived isotopes are &lt;a href=&quot;https://en.wikipedia.org/wiki/Incompatible_element&quot; rel=&quot;nofollow noreferrer&quot;&gt;incompatible elements&lt;/a&gt;. Moreover, uranium and thorium can be ruled out as sources of core heating due to geoneutrino observations. The neutrinos emitted by potassium decay are not detectible by current technology. Perhaps potassium behaves very differently under very high pressure and temperature.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;friction between the core and the more outer layers which spin more fast&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I'm not sure where you found this. As a general rule, it's the other way around: the core spins faster than the mantle. The mantle and crust are subject to tidal torques from the Moon that is gradually slowing the planet's rotation rate. The vast majority of this slow down results from interactions between ocean tides and the Earth's crust. This in turn makes the mantle rotate ever more slowly, and that in turn makes the core rotate ever more slowly. That said, this is a small contribution.&lt;/p&gt;&#xA;&lt;p&gt;You missed a key component, which is&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the formation and growth of the Earth's inner core&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;A liquid freezing into a solid is an exothermic reaction (a reaction that releases heat). The ongoing formation of the Earth's solid inner core adds heat to the core.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;However, I haven't found any indications that would point to the high pressure being a factor. So does the large pressure inside the Earth's core contribute to its high temperature?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;No.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-01-18T16:27:01.750" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24766" PostTypeId="1" CreationDate="2023-01-18T19:14:21.440" Score="2" ViewCount="32" Body="&lt;p&gt;There is no descriptive content on the interneton what Priessman slots are and how they can be used in numerical modeling. What is the benefit of that especially in hydraulic modeling?&lt;/p&gt;&#xA;" OwnerUserId="27888" LastEditorUserId="27888" LastEditDate="2023-01-18T20:13:36.793" LastActivityDate="2023-01-18T20:13:36.793" Title="What is the benefit of Priessman Slots in Numerical modeling?" Tags="|hydrology|numerical-modelling|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24767" PostTypeId="2" ParentId="24202" CreationDate="2023-01-19T02:55:33.617" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;The topographic isolation of a summit is the minimum horizontal (great circle) distance to the nearest point of higher elevation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;If this definition is altered so that the distance is to the nearest point of equal or higher elevation, then the definition works.&#xA;Starting at Everest, you would have to circle the Earth back to Everest before you find another peak of equal or higher elevation so the topographic isolation of Everset would be the circumference of the earth.&lt;/p&gt;&#xA;" OwnerUserId="28036" LastActivityDate="2023-01-19T02:55:33.617" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24768" PostTypeId="2" ParentId="24417" CreationDate="2023-01-19T06:27:31.897" Score="1" Body="&lt;p&gt;Volcanism+Water=Acid rain is the answer to this question.&lt;/p&gt;&#xA;&lt;p&gt;And now you all know where the free oxygen came from, it is from the acid.&lt;/p&gt;&#xA;&lt;p&gt;Mars is believed to have had a similar chemical composition as Earth had during the formation.&lt;/p&gt;&#xA;&lt;p&gt;If you add water to the atmosphere of Mars now you will make carbonic acid that will continue to form oxides on Mars.&lt;/p&gt;&#xA;" OwnerUserId="6258" LastEditorUserId="2470" LastEditDate="2023-01-19T08:23:52.487" LastActivityDate="2023-01-19T08:23:52.487" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24769" PostTypeId="2" ParentId="24417" CreationDate="2023-01-19T08:31:25.940" Score="9" Body="&lt;p&gt;The red color of Mars is due to hematite presence, Fe&lt;sup&gt;3+&lt;/sup&gt;&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;, in the martian soil and atmospheric dust.&lt;/p&gt;&#xA;&lt;p&gt;The size and concentration of the hematite particles present in a layer determines its color.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Hematite is a ferric oxide (α-Fe2O3), naturally occurring in three forms, mainly depending on the particle size of the samples (Lane et al., 1999): nanophase (dark purple, ∼&amp;lt;0.01 μm-diameter), fine-grained (red, diameter between about 0.01 and 10 μm), and coarse-grained (gray, ∼&amp;gt;10 μm-diameter).&lt;/p&gt;&#xA;&lt;p&gt;Pure crystalline hematite particulate samples with grain sizes between 0.01 μm and 10 μm (hereafter, normal red hematite samples) exhibit reflectance spectra that are saturated (near zero) in the violet and ultraviolet and steeply increase throughout the visible spectral range. This behavior explains the typical red color of this kind of hematite.&lt;/p&gt;&#xA;&lt;p&gt;(Marra et. al, 2011).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;There is no need of a high concentration of fine-grained hematite to give the layer a red color.&lt;/p&gt;&#xA;&lt;p&gt;Answering your question about the oxygen origin, martian soil is full of Fe-bearing compounds that, over the eons, have reacted with trace amounts of oxygen and water vapor in Mars' atmosphere to form iron oxide (source: &lt;a href=&quot;https://science.nasa.gov/science-news/science-at-nasa/2001/ast28mar_1&quot; rel=&quot;nofollow noreferrer&quot;&gt;science.nasa.gov&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;The Fe-rich compounds include a large variety of minerals. Analysis of Martian meteorites suggests that the planet's mantle is about twice as rich in iron as Earth's mantle (source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Composition_of_Mars&quot; rel=&quot;nofollow noreferrer&quot;&gt;Composition of Mars, Wikipedia.org&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;The superficial wind erosion of soils enriches the Martian atmospheric dust with fine-grained hematite, giving the Martian sky and soil their red appearance.&lt;/p&gt;&#xA;&lt;p&gt;Of particular interest to scientists is the formation of coarse-grained (grey) hematite spherules. Shao et. al, 2022 suggest that the erosion of spherules may have contributed to the fine-grained (red) hematite dispersion.&lt;/p&gt;&#xA;&lt;p&gt;The origin of hematite nodules has been widely debated. &lt;a href=&quot;https://scholar.google.es/scholar?hl=es&amp;amp;as_sdt=0,5&amp;amp;as_vis=1&amp;amp;q=origin%20of%20hemat%C3%ADe%20spherules%20mars&quot; rel=&quot;nofollow noreferrer&quot;&gt;You can find many papers discussing it&lt;/a&gt;, leading to some nice studies of Hawaiian hematite spherules.&lt;/p&gt;&#xA;&lt;p&gt;Things discussed:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;There was water on Mars.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Hydrothermal or aqueous diagenetic processes (sedimentary origin) have been proposed as the origin of iron oxides.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Meteorites.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Shao et. al, 2022:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The mechanisms of hematite spherule formation on Mars have been widely evaluated to understand the Martian surface conditions and their history. These Martian hematite spherules was suggested to have a sedimentary origin, with the spherules predicted to have formed in solutions through precipitation. In this study, we investigated the formation mechanism of hematite spherules on Mars by performing oxidative hydrothermal alteration experiments using reproduced I-type cosmic spherules. Our results suggest that Martian hematite spherules were formed by oxidation of Ni-bearing metallic spherules produced by ablation of iron meteorites during their entry into the Martian atmosphere. After long-term exposure on the surface of Mars, most spherules were pulverized because of oxidation. Some hematite fine grains blended into the Martian soil and were moved by storms, whereas others maintained their initial spherical shape with a high content of Ni. Notably, the precursor of Martian hematite spherules may be metallic spherules derived from iron meteorites.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Sexton et. al, 2017:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;By comparing our measured freezing rates with empirical and theoretical values from the literature, we conclude that the spherules on Mars could not have been produced through the freezing of aqueous hematite nanoparticle suspensions; ice crystallization front instability disrupts the aggregation process and prevents the formation of mm-scale continuous aggregates.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;-A.C. Marra, M.D. Lane, V. Orofino, A. Blanco, S. Fonti (2011),&amp;quot;Midinfrared spectra and optical constants of bulk hematite: Comparison with particulate hematite spectra&amp;quot;, &lt;em&gt;Icarus&lt;/em&gt;, Volume 211, Issue 1, Pages 839-848, ISSN 0019-1035, &lt;a href=&quot;https://doi.org/10.1016/j.icarus.2010.09.021&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/j.icarus.2010.09.021&lt;/a&gt;.&#xA;(&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S001910351000374X&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/S001910351000374X&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;-M.R. Sexton, M.E. Elwood Madden, A.L. Swindle, V.E. Hamilton, B.R. Bickmore, A.S. Elwood Madden (2017):&amp;quot;Considering the formation of hematite spherules on Mars by freezing aqueous hematite nanoparticle suspensions&amp;quot;, &lt;em&gt;Icarus&lt;/em&gt;, Volume 286, Pages 202-211, ISSN 0019-1035,&#xA;&lt;a href=&quot;https://doi.org/10.1016/j.icarus.2016.10.014&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/j.icarus.2016.10.014&lt;/a&gt;.&#xA;(&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0019103516301567&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/S0019103516301567&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;-Huimin Shao, Hiroshi Isobe, Ginga Kitahara, Akira Yoshiasa (2022):&amp;quot;Formation of hematite spherules from metallic spherules by oxidative hydrothermal alteration: Implications for hematite spherules on Martian surface&amp;quot;, Planetary and Space Science, Volume 222, 105565, ISSN 0032-0633,&#xA;&lt;a href=&quot;https://doi.org/10.1016/j.pss.2022.105565&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/j.pss.2022.105565&lt;/a&gt;.&#xA;(&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0032063322001519&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/S0032063322001519&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerDisplayName="user28185" LastEditorDisplayName="user28185" LastEditDate="2023-03-11T16:22:03.977" LastActivityDate="2023-03-11T16:22:03.977" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24770" PostTypeId="1" AcceptedAnswerId="24771" CreationDate="2023-01-19T15:04:28.977" Score="6" ViewCount="118" Body="&lt;p&gt;I have read that the University of Chile uses seismic data to produce random numbers.  (&lt;a href=&quot;https://random.uchile.cl/randomness-beacon&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://random.uchile.cl/randomness-beacon&lt;/a&gt;). Does seismic data real have randomness and if it so, which information is used in seismic data: magnitude, time, vb.?&lt;/p&gt;&#xA;" OwnerUserId="28329" LastEditorUserId="2470" LastEditDate="2023-01-20T00:19:36.120" LastActivityDate="2023-01-21T14:59:29.250" Title="How to produce random numbers from seismic data?" Tags="|seismic|mathematics|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24771" PostTypeId="2" ParentId="24770" CreationDate="2023-01-19T15:33:51.867" Score="3" Body="&lt;p&gt;This quote is from the article:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Use of Local Entropy: after collecting data from the external sources, it is necessary to generate entropy locally. For that, we use our own TRNG (True Random Number Generator), a piece of hardware that produces random bits by relying on a quantum process on an electrical circuit. At every minute, the TRNG generates a 512 bit value.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I found the article confusing. They allude to seismic data being used but the quote from the article suggests that the random number is generated using hardware that generates the random number based on quantum mechanical processes.&lt;/p&gt;&#xA;&lt;p&gt;The article also mentions the use of cryptography. Perhaps the daily seismic data (which is essentially unpredictable), is used as a seed for the cryptography.&lt;/p&gt;&#xA;" OwnerUserId="28036" LastActivityDate="2023-01-19T15:33:51.867" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24772" PostTypeId="2" ParentId="24770" CreationDate="2023-01-21T14:59:29.250" Score="1" Body="&lt;p&gt;Any unpredictable source that can contribute to numerical entropy is a good source for trying to generate truly unpredictable random numbers. People even use the somewhat unpredictable timing of how long it takes to access data on a disk drive as a source of randomness. Generating truly random numbers is an impossible task. That does not mean that &lt;a href=&quot;https://en.wikipedia.org/wiki//dev/random&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;code&gt;/dev/random&lt;/code&gt;&lt;/a&gt; and all of the sources that feed it are not a good start. They are. Similar concepts exist on other operating systems. In general, the more entropy the better.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-01-21T14:59:29.250" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24773" PostTypeId="1" AcceptedAnswerId="24774" CreationDate="2023-01-21T19:23:59.563" Score="4" ViewCount="196" Body="&lt;p&gt;I have been doing a lot of research on the Internet lately about various desalination processes which are being used today and this led me to begin studying about mountain weather and the orographic effect (or orographic lifting).&lt;/p&gt;&#xA;&lt;p&gt;From studying mountain weather, the thought occurred to me about whether a lot of fresh water could be produced by creating an artificially-produced orographic effect by pumping warm, humid coastal air through a pipeline that would lead to the top of a coastal mountain.&lt;/p&gt;&#xA;&lt;p&gt;Orographic Effect:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZwC3g.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZwC3g.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I then used MS Paint to make a conceptual drawing on how this could be done:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mxp31.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mxp31.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Since the temperature of the metal pipe will decrease as it ascends up the coastal mountain, contact with this colder metal should cause the water vapor within the pumped air to condense on the inner wall of the pipeline and forming water droplets. These water droplets should then be pulled down by gravity and should fall into a pipe leading to a water storage tank.&lt;/p&gt;&#xA;&lt;p&gt;In the case that one air pumping plant cannot produce enough air pressure to push the air all the way up a mountain, then perhaps another air pumping plant could be stationed near the top of the mountain to assist with transporting the air upwards through the pipeline.&lt;/p&gt;&#xA;&lt;p&gt;These air pumping plants would probably need to have a large volume industrial centrifugal blower fan like the ones built by Elektror Airsystems pictured here:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5VEg2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5VEg2.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Reference: &lt;a href=&quot;https://www.elektror.com/en/products/industrial-blowers/large-volume-fans/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.elektror.com/en/products/industrial-blowers/large-volume-fans/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I am neither a climatologist nor a scientist so I really don't how much fresh water could be produced this way. I am looking for someone in Earth Science.SE to give me just a ballpark figure of how much water may be produced by this process.&lt;/p&gt;&#xA;&lt;p&gt;Say that this pipeline is 2.5 meters in diameter, the top of the mountain is 2500 meters high, the air temperature at the top of the mountain is 280 Kelvin, the coastal air temperature is 302 Kelvin, and the coastal air humidity is at 70%.&lt;/p&gt;&#xA;&lt;p&gt;How much fresh water could be produced by pumping warm humid air through a pipeline up to the top of a mountain?&lt;/p&gt;&#xA;" OwnerUserId="23275" LastEditorUserId="23275" LastEditDate="2023-01-23T03:09:33.377" LastActivityDate="2023-01-23T03:09:33.377" Title="How much fresh water could be produced by pumping warm humid air through a pipeline up to the top of a mountain?" Tags="|meteorology|geophysics|water|climatology|water-vapour|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="24774" PostTypeId="2" ParentId="24773" CreationDate="2023-01-22T02:57:24.597" Score="3" Body="&lt;p&gt;Using the relative humidity and temperature, the g/kg ratio of water to dry air can be calculated. Using an online rh calculator, a relative humidity of 70% and a temperature of  302 K  at 1 atm yields 17.54 grams water/kg air. This is the maximum amount of water that can be extracted.&lt;/p&gt;&#xA;&lt;p&gt;Using an online calculator, the density of dry air at 302K and 1 atm is 1.16882 kg/cu m.&lt;/p&gt;&#xA;&lt;p&gt;The total volume of your pipe (2.5 m diameter with a height of 2500 m) = 12,271.85 cu m.&lt;/p&gt;&#xA;&lt;p&gt;This holds 14,343.58 kg dry air and 251,586.45 grams (251 L) of water or 66.5 gallons of water.&lt;/p&gt;&#xA;&lt;p&gt;So, the maximum possible is 66.5 gallons/pipe of air. Your design won't extract this much and it's likely to get less than half this.&lt;/p&gt;&#xA;&lt;p&gt;I haven't calculated is how much time is required to extract all the water from a full pipe of air but I can't imagine this being a fast process and wouldn't be surprised if it took several hours.&lt;/p&gt;&#xA;&lt;p&gt;Based on this simple analysis, the cost/benefit ratio would be much too high to invest in a project like this. Remember that you are competing with existing technology that according to Texas:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Texas Water Development Board states a good rule of thumb is \$1.10-2.40 per 1,000 gallons for brackish water and $2.46-4.30 per 1,000 gallons for seawater desalination.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="28036" LastEditorUserId="28036" LastEditDate="2023-01-23T02:09:09.423" LastActivityDate="2023-01-23T02:09:09.423" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="24775" PostTypeId="1" CreationDate="2023-01-22T17:33:38.043" Score="1" ViewCount="77" Body="&lt;p&gt;I understand that different objects absorb different amounts of light (blackbody absorption). I wonder how feasible it would be to calculate the approximate temperature in the sun based upon the forecasted temperature (shade) — essentially a &amp;quot;feels like&amp;quot; in the sun. It's always some number of degrees warmer... it would be nice to quantify that. Does that depend on the absorption of a given person's skin (and thus vary depending upon their skin tone)? If so, would it be possible to calibrate an equation that predicts feels like temp in the sun by various lighter and darker skin tones? (see the &lt;a href=&quot;https://en.wikipedia.org/wiki/Fitzpatrick_scale&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fitzpatrick scale&lt;/a&gt; for reference)&lt;/p&gt;&#xA;&lt;p&gt;Note that I'm not talking about extant &amp;quot;feels-like&amp;quot; temperatures reported in forecasts, wind chill (calculated by wind speed) and the heat index (using the dew point), but a theoretical third &amp;quot;feels-like&amp;quot; number based upon exposure in the sun (using a blackbody or radiative transfer determinant).&lt;/p&gt;&#xA;" OwnerUserId="28338" LastActivityDate="2023-01-22T17:33:38.043" Title="Forecasted temperature in the shade vs. theoretical &quot;feels-like&quot; temperature in the sun" Tags="|meteorology|temperature|weather-forecasting|thermodynamics|radiative-transfer|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24776" PostTypeId="2" ParentId="18105" CreationDate="2023-01-23T01:11:56.847" Score="7" Body="&lt;p&gt;The answer is no. One important mechanism that also fixes carbon is &lt;a href=&quot;https://en.wikipedia.org/wiki/Chemosynthesis&quot; rel=&quot;noreferrer&quot;&gt;chemosynthesis&lt;/a&gt;. One good example of this production is around &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydrothermal_vent&quot; rel=&quot;noreferrer&quot;&gt;hydrothermal vents&lt;/a&gt; in the bottom of the ocean.&lt;/p&gt;&#xA;&lt;p&gt;Chemosynthesis is the biological production of organic matter from single-carbon compounds like &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; and nutrients using the energy generated by the oxidation of inorganic or organic molecules (instead of solar energy). This diagram shows one of the example pathways that produce organic carbon (sugars) from &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt;, water, and a source of chemical energy coming from hydrogen sulfide produced by volcanic activity at the hydrothermal vent.&lt;/p&gt;&#xA;&lt;p&gt;The source of the &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; in this case is dissolved carbon dioxide in the saltwater. The existing &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; concentration in these environments is enhanced in some cases (but not necessarily) by the volcanic activity in the area.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/m4c4k.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/m4c4k.jpg&quot; alt=&quot;Hydrothermal vent chemistry&quot; /&gt;&lt;/a&gt;&#xA;Source: &lt;a href=&quot;https://teara.govt.nz/files/large_images/8960-enz_0.jpg&quot; rel=&quot;noreferrer&quot;&gt;Teara&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="111" LastEditorUserId="18081" LastEditDate="2023-01-24T08:15:43.020" LastActivityDate="2023-01-24T08:15:43.020" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24777" PostTypeId="2" ParentId="4798" CreationDate="2023-01-23T01:48:32.333" Score="3" Body="&lt;p&gt;One possibility is that enough uranium is present to provide a substantial heat source -- in the deep mantle rather than the core.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1029/2006GL027508&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gautron et al.[1]&lt;/a&gt; study the inclusion of uranium in an aluminum-doped calcium silicate perovskite, which is believed to exist in the lower mantle (the authors cite Ref. &lt;a href=&quot;https://doi.org/10.1029/2001JB000597&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;). With the aluminum doping, the silicate perovskite becomes compatible with uranium(IV), and thereby &amp;quot;all the uranium present in this region could be easily stored via its insertion in the Al-CaSiO3 perovskite.&amp;quot; The authors suggest that thorium, which also favors the +4 oxidation state and forms a similarly large cation, may similarly be incorporated, although they directly studied only uranium.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Laurent Gautron, Steeve Greaux, Denis Andrault, Nathalie Bolfan-Casanova, Nicolas Guignot, M. Ali Bouhifd (2006). &amp;quot;Uranium in the Earth's lower mantle&amp;quot;. &lt;em&gt;Geophysical Research Letters&lt;/em&gt; &lt;strong&gt;33&lt;/strong&gt;(23), L23301. &lt;a href=&quot;https://doi.org/10.1029/2006GL027508&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1029/2006GL027508&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Hirose, K. (2002). &amp;quot;Phase transitions in the pyrolitic mantle around 670–km depth: Implications of upwellings of plumes from the lower mantle&amp;quot;. &lt;em&gt;J. Geophys. Res.&lt;/em&gt;, &lt;strong&gt;107&lt;/strong&gt;(B4), 2078. &lt;a href=&quot;https://doi.org/10.1029/2001JB000597&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1029/2001JB000597&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2023-02-11T01:54:57.740" LastActivityDate="2023-02-11T01:54:57.740" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24778" PostTypeId="2" ParentId="24773" CreationDate="2023-01-23T01:57:42.947" Score="3" Body="&lt;p&gt;All kinds of additional problems too:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Your given values equate (&lt;a href=&quot;https://www.weather.gov/epz/wxcalc_mixingratio&quot; rel=&quot;nofollow noreferrer&quot;&gt;RH calc&lt;/a&gt;)(&lt;a href=&quot;https://bmcnoldy.rsmas.miami.edu/Humidity.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;dewpoint calc&lt;/a&gt;) to a dewpoint of 73°F, rare to find (mostly towards summer in limited areas... for the US: mostly the Plains/Midwest/South).  And water content of air drops markedly if cooler... a dewpoint of 50F is only 7 g/kg, a dewpoint of 20F is nearer 2 g/kg.  Not much water content at all (and only a fraction is removed by lifting 2.5 km)  Take a look at the current dewpoint map for the &lt;a href=&quot;https://www.mesonet.org/index.php/weather/map/dewpoint1/dewpoint_humidity&quot; rel=&quot;nofollow noreferrer&quot;&gt;US&lt;/a&gt; or &lt;a href=&quot;https://www.weathertrends360.com/Maps/Interactive?v=radar&amp;amp;utm_source=map_share_link&amp;amp;dataType=current&amp;amp;z=3&amp;amp;lat=26.118676855414314&amp;amp;lon=12.102590237968766&amp;amp;frame=13&quot; rel=&quot;nofollow noreferrer&quot;&gt;world&lt;/a&gt; to see just how low dewpoint values often are.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;You're also extracting the water where there's already plenty of natural water extraction (it's rainy in those orographic locations)... especially those that have the tropical temp/dewpoints you set.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;And then the air needs quite a bit of energy to travel 2.5 km... especially since it's 2.5 km uphill. Just gravitational PE looks like 343 MJ, which if done very slowly (over 3 hours) is 32 kWhr each hour, and at 10 mph would be more like 570 kWhr each hour.  Which is roughly 30-600 &lt;a href=&quot;https://shrinkthatfootprint.com/average-household-electricity-consumption/&quot; rel=&quot;nofollow noreferrer&quot;&gt;homes worth&lt;/a&gt;.  You're talking 150-3000 400W solar panels worth and getting up near a &lt;a href=&quot;https://www.electricchoice.com/electricity-prices-by-state/&quot; rel=&quot;nofollow noreferrer&quot;&gt;fullscale wind turbine&lt;/a&gt; for the 10 mph throughput.  Or in the range of \$20000-\$1.25 million (USD) to purchase the power each year, depending on &lt;a href=&quot;https://www.electricchoice.com/electricity-prices-by-state/&quot; rel=&quot;nofollow noreferrer&quot;&gt;the location&lt;/a&gt; and which speed you choose.  [Someone feel free to check my math, please!!]  And this is if your fans/heaters somehow had 100% efficiency.  (You may wind up being better off heating the input air instead, which could make it unstable such that it would rise on its own?  And perhaps you can benefit a bit by channeling wind into the ramp when it's from a different direction than the pipeline... but even with both, energy usage is still likely to be significant)&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;And if done at scale... there's also an extra concern... the resulting air downstream loses the moisture you took out... meaning spots where moisture is already scarcer [deserts and such] have even less... and may not be too happy... lawsuit?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;So unfortunately you're providing water where it usually isn't that needed, and have significant limitations of cost and efficiency if/when you would need to use the device.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2023-01-23T02:07:47.910" LastActivityDate="2023-01-23T02:07:47.910" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24779" PostTypeId="1" AcceptedAnswerId="24780" CreationDate="2023-01-23T15:55:25.640" Score="3" ViewCount="93" Body="&lt;p&gt;According to Coriolis force an air parcel is deflected in the absence of other forces by the acceleration (Holton, 4th Edition):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aCxKF.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aCxKF.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;These equations lead to circular motion.&lt;/p&gt;&#xA;&lt;p&gt;This figure is from a Matlab script, provided by Holton:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HyBTA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HyBTA.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But how is this consistent with the picture, where an object moves along a straight line in the inertial system and the deflection is only apparently because we are in a rotating frame? If the object moves along a straight line in the inertial system, the curve cannot be circular in the rotating frame.&lt;/p&gt;&#xA;&lt;p&gt;It's due to the disappearance of vertical motion, I think. But in Holton, the third equation is simply left out without comment, and instead only the above two equations are finally written. It is clear that the above equations come out when the vertical velocity is zero, but this is not justified in the explanations. Is this just an empirical observation?&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2023-01-23T17:55:13.853" LastActivityDate="2023-01-23T19:22:01.823" Title="Why air parcel is on a circular trajectory when considering Coriolis force" Tags="|meteorology|atmosphere|atmosphere-modelling|fluid-dynamics|atmospheric-circulation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24780" PostTypeId="2" ParentId="24779" CreationDate="2023-01-23T19:22:01.823" Score="5" Body="&lt;p&gt;The parcel in question is not moving in a straight line. It is a particle at rest in the reference frame rotating earth. A &amp;quot;fixed&amp;quot; observer in space would  see a particle moving in circles with angular frequency &lt;span class=&quot;math-container&quot;&gt;$\Omega$&lt;/span&gt; (earths angular frequency) and angular velocity &lt;span class=&quot;math-container&quot;&gt;$u_a$&lt;/span&gt; which is given by &lt;span class=&quot;math-container&quot;&gt;$u_a=\Omega R$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; is the distance of the particle to the axis of rotation (compare to figures 1.6 and 1.8 in Holton).&lt;/p&gt;&#xA;&lt;p&gt;To unterstand the circular motion we need to take the angular momentum &lt;span class=&quot;math-container&quot;&gt;$L$&lt;/span&gt; into account which is given by &lt;span class=&quot;math-container&quot;&gt;$L = mRu_a$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$m$&lt;/span&gt; is the particles mass. &lt;span class=&quot;math-container&quot;&gt;$L$&lt;/span&gt; is a conserved quantity.&lt;/p&gt;&#xA;&lt;p&gt;Let's see what this means based on the plot you provided: Suppose the particle is initially at rest at 44° latitude. If we push the parcel towards the north pole while keeping its vertical distance to sea level constant (compare to Holton: &amp;quot;Suppose that an object of unit mass, initially at latitude φ moving zonally at speed u, relative to the surface of the earth, is displaced in latitude or in altitude by an impulsive force&amp;quot;), we reduce the distance &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; of the particle to the axis of rotation. In order for &lt;span class=&quot;math-container&quot;&gt;$L$&lt;/span&gt; to stay the same either &lt;span class=&quot;math-container&quot;&gt;$u_a$&lt;/span&gt; needs to increase (or the mass has to change, which by mass conservation does not happen).&#xA;An observer on earth at 44 degrees north looking towards the North Pole would recognise a deflection of the particle towards the east as the particle is accelerating in order to conserve momentum.&lt;/p&gt;&#xA;" OwnerUserId="18833" LastActivityDate="2023-01-23T19:22:01.823" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24781" PostTypeId="2" ParentId="24636" CreationDate="2023-01-23T21:12:00.710" Score="2" Body="&lt;p&gt;Equinor released a complete data set from the Volve field 2008-2016. From their website, it appears that the data is intended for the researchers. It has data from the sonic tool as well.&lt;/p&gt;&#xA;&lt;p&gt;Here is the link &lt;a href=&quot;https://www.equinor.com/energy/volve-data-sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;Volve field data set&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28344" LastActivityDate="2023-01-23T21:12:00.710" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24782" PostTypeId="1" CreationDate="2023-01-24T11:27:31.773" Score="6" ViewCount="45" Body="&lt;p&gt;Differential absorption in the near-infrared is used to retrieve total column water vapour from MODIS (Gao and Kaufman, 2003), OLCI (Preusker et al., 2021), and others.  The idea is that reflected sunlight in one channel is strongly attenuated by water vapour, but not in the nearby window channel, while other properties (aerosol absorption, surface properties) are similar enough such that the difference or ratio between the reflectances can be attributed mostly to total column water vapour.  Reading about this principle in the context of OLCI I came across the term &lt;em&gt;ρστ-absorption band&lt;/em&gt;.  Some examples:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.eumetsat.int/COWA&quot; rel=&quot;noreferrer&quot;&gt;&lt;em&gt;water vapour absorption within the 940 nm ρστ-absorption band&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.mdpi.com/2072-4292/13/5/932&quot; rel=&quot;noreferrer&quot;&gt;&lt;em&gt;using the ratio of&#xA;measurements in the ρστ-absorption band and a nearby window band&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.researchgate.net/publication/249605101_Empirical_Correction_of_Stray_Light_within_the_MERIS_Oxygen_A-Band_Channel&quot; rel=&quot;noreferrer&quot;&gt;&lt;em&gt;like the oxygen A band at 0.76 μm or the ρστ absorption band of water vapor around 0.9 μm&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2002GL016523&quot; rel=&quot;noreferrer&quot;&gt;&lt;em&gt;studied using the ρστ-water vapor absorption band&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Why is it called the ρστ absorption band?&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2023-01-24T11:27:31.773" Title="Why is the ρστ absorption band called the ρστ absorption band?" Tags="|remote-sensing|terminology|earth-observation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24783" PostTypeId="1" AcceptedAnswerId="24785" CreationDate="2023-01-24T11:59:05.233" Score="7" ViewCount="725" Body="&lt;p&gt;In the &lt;a href=&quot;https://www.nature.com/articles/s41561-022-01112-z.epdf?sharing_token=EFokPjqDXD2xTXNkcCZzMNRgN0jAjWel9jnR3ZoTv0N-n5CKH8sZM_u5cEFurTAJryk-7LHJO5K2v-0f42K8qTqm3tErZjVR7WlBTrcXbiQymqyMI5rO0DBZxX3Vfnw62N0W85VtF-CSmohZ-IN-6su6_TmNvBNo_FLhHaCfJ5hucVESsL8wX_JkhwvtSPT-yN-2Hw1rq0u-LBYs6nd8cg%3D%3D&amp;amp;tracking_referrer=elpais.com&quot; rel=&quot;noreferrer&quot;&gt;recent paper published in Nature&lt;/a&gt; that sugests a 60-70 years inner core rotation cycle, it is said:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Interestingly, the same multidecadal periodicity is also well observed&#xA;in the Earth’s climate system, especially the global mean&#xA;temperature and sea level rise.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The assertion quotes &lt;a href=&quot;https://www.nature.com/articles/367723a0&quot; rel=&quot;noreferrer&quot;&gt;this paper&lt;/a&gt; published in 1994.&lt;/p&gt;&#xA;&lt;p&gt;Is this multidecadal climate cycle well accepted among climatologists? It was maybe attributed to other causes than the inner core rotation before this study?&lt;/p&gt;&#xA;&lt;p&gt;How can then the inner core rotation influence climate?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;-Yang, Y., Song, X. (2023): &amp;quot;Multidecadal variation of the Earth’s inner-core rotation.&amp;quot; Nature Geoscience. &lt;a href=&quot;https://doi.org/10.1038/s41561-022-01112-z&quot; rel=&quot;noreferrer&quot;&gt;https://doi.org/10.1038/s41561-022-01112-z&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;-Schlesinger, M., Ramankutty, N. (1994) &amp;quot;An oscillation in the global climate system of period 65–70 years.&amp;quot; Nature 367, 723–726. &lt;a href=&quot;https://doi.org/10.1038/367723a0&quot; rel=&quot;noreferrer&quot;&gt;https://doi.org/10.1038/367723a0&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user28185" LastEditorDisplayName="user28185" LastEditDate="2023-01-24T12:49:18.170" LastActivityDate="2024-01-16T06:51:20.857" Title="How does the rotation of Earth's inner core influence climate?" Tags="|geophysics|climatology|core|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24784" PostTypeId="2" ParentId="24636" CreationDate="2023-01-24T13:26:37.200" Score="1" Body="&lt;p&gt;For &lt;strong&gt;USA&lt;/strong&gt; data, I recommend searching state-by-state (preferably ones that are well-developed [Alaska, Texas, Louisiana, New Mexico, Pennsylvania, etc.]) and specifically targeting data sources that are the state-level commissions for all past/current/future leases. For example, the Texas Rail Road Commission (or RRC) has a lot of info that &lt;em&gt;may&lt;/em&gt; provide the type of well-log data you seek. &lt;a href=&quot;https://www.rrc.texas.gov/oil-and-gas/research-and-statistics/obtaining-commission-records/oil-gas-well-records-gis-well-logs/&quot; rel=&quot;nofollow noreferrer&quot;&gt;See here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;For some other &lt;strong&gt;data from elsewhere&lt;/strong&gt;, check &lt;a href=&quot;https://terranubis.com/datainfo/F3-Demo-2020&quot; rel=&quot;nofollow noreferrer&quot;&gt;this huge data set&lt;/a&gt; out from dGB (and OpendTect) from the North Sea.&lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2023-01-24T13:26:37.200" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24785" PostTypeId="2" ParentId="24783" CreationDate="2023-01-24T13:58:56.693" Score="6" Body="&lt;p&gt;I have four things to say regarding this:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The paper is far too new. I'm not saying the first paper is wrong (it is in fact rather interesting), but having been published yesterday, it is far too new to be used as the basis for anything. Publication in a peer-reviewed journal is where science starts rather than ends. Wait a bit for the scientific community to confirm or reject the claims in this paper.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The two effects might be completely unrelated.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;If they are related, you might be confusing cause and effect. It could be that whatever causes the climate oscillations in turn causes the oscillations in the inner core's rotation rate.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;What the authors of the paper in question are reporting to have observed is a small differential rotation between the mantle+crust and the inner core. It could well be that the inner core rotates much more smoothly than does the mantle+crust. In other words, they're seeing variations in the rotation rate of the mantle+crust.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;We know as a fact that the Earth's rotation rate is gradually slowing down. Scientists see this far in the past in tidal rhythmites locked in stone. More recent signs were ancient astronomers/astrologers (the two were the same &amp;quot;science&amp;quot; up to Kepler's time) who recorded solar eclipses at specific cities. Those solar eclipses would have happened elsewhere on the Earth if the Earth maintained a more or less constant rotation rate.&lt;/p&gt;&#xA;&lt;p&gt;Thanks to atomic clocks and long baseline interferometry, scientists readily see seasonal changes in the Earth's rotation rate. Snow falls on the northern parts of the North Hemisphere in winter and melts in the summer. That represents transfers of angular momentum between the oceans, the cryosphere, and the crust. These variations are easy to see.&lt;/p&gt;&#xA;&lt;p&gt;Precise measurements of the Earth's rotation rate also show what appears to be longer term oscillations in the Earth's rotation. It appears that there is a multidecadal oscillation in the Earth's rotation rate that is correlated with the 60 to 70 year Atlantic Multidecadal Oscillation (AMO). Since very good data on the Earth's rotation only goes back 60 to 70 years, it's a not quite conclusive. The same goes for the AMO; very good meteorological data only goes back 100 years or so. The cause of the AMO is debated. The teleconnections between it and other climate observations are also debated. However, the AMO does appear to impact climate, and climate in turn appears to impact Earth rotation. (We know climate as a fact that impacts Earth rotation on a yearly basis.)&lt;/p&gt;&#xA;&lt;p&gt;The Earth comprises multiple rotating parts: The atmosphere, the cryosphere, the oceans, the crust and mantle, the liquid outer core, and the solid inner core. These different parts exchange angular momentum with one another (and also with the Moon). Except for the seasonal variations and the long term secular transfer to the Moon, teasing out cause and effect in the variations of the Earth's rotation rate is a non-trivial exercise.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2023-01-25T11:38:41.300" LastActivityDate="2023-01-25T11:38:41.300" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24786" PostTypeId="1" CreationDate="2023-01-25T00:12:35.697" Score="2" ViewCount="18" Body="&lt;p&gt;As the question probably shows, I am not really versed in geological sciences, but it is rather a worldbuilding question I have regarding a setting based on the North Carolina area of the USA. Would a mining town be able to extract feldspar without going too far away from any iron deposits, or would the two of them be separated enough to make the effort of establishing a settlement to mine one or the other viable?&lt;/p&gt;&#xA;&lt;p&gt;As always, apologies if the question or its format is not welcome in the forum and thanks in advance for any answer.&lt;/p&gt;&#xA;" OwnerUserId="28352" LastActivityDate="2023-01-25T00:12:35.697" Title="Is Feldspar likely to occur near iron ores, next to them, or mixed with them?" Tags="|geology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24787" PostTypeId="1" AcceptedAnswerId="24788" CreationDate="2023-01-25T02:57:21.547" Score="18" ViewCount="4899" Body="&lt;p&gt;Recent news articles related to &lt;a href=&quot;https://www.nature.com/articles/s41561-022-01112-z.epdf&quot; rel=&quot;noreferrer&quot;&gt;this paper&lt;/a&gt; report the claim that Earth's solid inner core sometimes rotates backwards. The literal claim (as it appears in headlines) seems to make no sense given a basic understanding of friction and conservation of angular momentum. The matter is discussed in &lt;a href=&quot;https://earthscience.stackexchange.com/questions/402/why-does-earths-outer-core-rotate-in-the-opposite-direction-to-the-inner-core&quot;&gt;this SE question&lt;/a&gt;, but there is also the matter of multi-decadal cycles. What is the actual assertion? Is the inner core thought to be cycling between prograde and retrograde rotation, or is it something more subtle, like a wobble, sometimes slightly leading and sometimes slightly lagging, and at what amplitude? Is it a matter of &amp;quot;gaining&amp;quot; or &amp;quot;losing&amp;quot; a few degrees over some number of years (so would only be rotating &amp;quot;backwards&amp;quot; in the frame of reference of the crust, not non-rotating space)?&lt;/p&gt;&#xA;" OwnerUserId="1210" LastActivityDate="2023-01-27T18:11:07.207" Title="Does Earth's core actually turn &quot;backwards&quot; at times?" Tags="|earth-rotation|" AnswerCount="2" CommentCount="17" ContentLicense="CC BY-SA 4.0" />
  <row Id="24788" PostTypeId="2" ParentId="24787" CreationDate="2023-01-25T03:32:48.573" Score="26" Body="&lt;p&gt;The mantle rotates about 131850 degrees per year. The actual assertion is that the inner core cycles between rotating about 131851 degrees per year versus 131849 degrees per year over the course of 70 year cycle. The paper was only published yesterday, so the scientific consensus is not there yet. The scientific consensus is not there yet on work done by the same authors eight years ago.&lt;/p&gt;&#xA;&lt;p&gt;The inner core rotates in the same direction as do the mantle and crust, and rotates at almost at the same rate as the mantle and crust. The claim is that this rate varies by a tiny fraction compared to the mantle's rotation rate, plus or minus a degree or so per year compared to the mantle (but keep in mind that is one degree out of 131850 degrees). It does not switch directions.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-01-25T03:32:48.573" CommentCount="13" ContentLicense="CC BY-SA 4.0" />
  <row Id="24789" PostTypeId="1" AcceptedAnswerId="24790" CreationDate="2023-01-25T03:47:39.497" Score="45" ViewCount="12126" Body="&lt;p&gt;Why is sodium chloride far and away the most abundant salt dissolved in ocean water? Its two constituent ions do have a very high frequency in the crust of the earth, but they are far from the most common. Chlorine is (according to &lt;a href=&quot;https://en.wikipedia.org/wiki/Chlorine&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;) the 21st most abundant element, and &lt;a href=&quot;https://en.wikipedia.org/wiki/Sodium&quot; rel=&quot;noreferrer&quot;&gt;sodium&lt;/a&gt; 6th.&lt;/p&gt;&#xA;&lt;p&gt;I certainly understand that a combination of their solubility and reasonably high frequency would lead one to expect them to be abundant in sea water, but they are hyper abundant, completely dominating all other salt ions. Iron, for example, is twice as abundant, and potassium only a little less abundant, and fluorine more abundant than chlorine.&lt;/p&gt;&#xA;&lt;p&gt;Moreover, if the salts are deposited in the ocean through weathering of rocks and deposition via rivers, why does the salinity not simply grow and grow? I understand that some is lost due to tectonic activity, but it seems extraordinarily unlikely that these two forces should be equally balanced, and so we would see a significant change in average salinity over time.&lt;/p&gt;&#xA;&lt;p&gt;(Please note I am migrating this question from the Chemistry SE at their recommendation.)&lt;/p&gt;&#xA;" OwnerUserId="28353" LastEditorUserId="502" LastEditDate="2023-01-27T01:09:40.740" LastActivityDate="2023-01-27T01:09:40.740" Title="Why is NaCl so hyper abundant in the ocean?" Tags="|oceanography|geochemistry|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24790" PostTypeId="2" ParentId="24789" CreationDate="2023-01-25T05:01:11.193" Score="50" Body="&lt;p&gt;Fluoride salts tend to be not particularly soluble in water. Chloride salts are. The same goes for salts containing sodium versus those containing calcium. Sodium chloride is ridiculously easy to dissolve.&lt;/p&gt;&#xA;&lt;p&gt;Regarding your second question, it is geological forces that keep salinity more or less constant. People formerly argued that the Earth can't be more than a few hundred million years old because otherwise the river waters running into the oceans would eventually result in an insanely high salinity. It turns out that the Earth's oceans are young (young compared to the 4.5 billion year age of the Earth). The vast majority of oceanic crust is less than 100 million years old. We see huge salt deposits sprinkled across the world because those are the dried up remnants of former seas and oceans. Salt is also drawn into the Earth at subduction zones, where it combines chemically with basalt.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-01-25T05:01:11.193" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24791" PostTypeId="2" ParentId="24789" CreationDate="2023-01-25T14:23:45.983" Score="44" Body="&lt;p&gt;Solubility. The question is quite chemical, in fact.&lt;/p&gt;&#xA;&lt;p&gt;Solubility works somewhat counter-intuitively: if two ions that are not soluble together are present in the solution, they find each other and form a solid. You can mix e.g. sodium carbonate (soluble) and calcium chloride (soluble) and get calcium carbonate (insoluble).&lt;/p&gt;&#xA;&lt;p&gt;This is why oceans don't contain much of calcium - they contain quite a deal of carbonate.&lt;/p&gt;&#xA;&lt;p&gt;If one makes the ocean more acidic, the carbonate ion will be much less and we could indeed have calcium in the solution.&lt;/p&gt;&#xA;&lt;p&gt;We can't have much iron either - iron ions are insoluble because they precipitate with hydroxide ions and you need quite an acidic solution in order to have barely soluble iron.&lt;/p&gt;&#xA;&lt;p&gt;The same phenomenon explains the weathering - the rainwater and aquifiers wash away ions depending on their own initial ion content (including acidity).&lt;/p&gt;&#xA;&lt;p&gt;What's important with NaCl? Both its ions are quite soluble in the presence of almost any other ion. This is why they are easy to leach from the stones and rocks and in fact we are almost done with this. This is why rivers don't bring much salt into the oceans these days - there is no much of them left.&lt;/p&gt;&#xA;&lt;p&gt;P.s. in regard to iron - long ago, before the first bacteria learned to produce oxygen, the ocean was full of iron. It was Fe&lt;sup&gt;2+&lt;/sup&gt; - this is the form stable when no oxygen is present. Fe&lt;sup&gt;2+&lt;/sup&gt; is much more soluble than the more oxidized form (Fe&lt;sup&gt;3+&lt;/sup&gt;). This is how some large iron ore deposits formed.&lt;/p&gt;&#xA;" OwnerUserId="18660" LastEditorUserId="2958" LastEditDate="2023-01-25T20:30:47.857" LastActivityDate="2023-01-25T20:30:47.857" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="24792" PostTypeId="1" CreationDate="2023-01-25T17:34:59.593" Score="8" ViewCount="53" Body="&lt;p&gt;I have just started a course in hydrology (a totally different field from mine which is computer science) and I can't find the link between the fact that a river flows into a lake and the % of precipitation falling as snow. I'm really confused. Can someone explain the principle (questions a and b being trivial)? The problem is posed below:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Problem:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;A watershed has an area of 300 km2. Annual precipitation in this watershed has averaged 1039 mm over the past 30 years. Data from a stream gauging station at the outlet of this watershed indicate that the average flow rate has been 3,900 l/s over these 30 years.&lt;/p&gt;&#xA;&lt;p&gt;a) What is the annual volume of precipitation in this basin in m3?&lt;/p&gt;&#xA;&lt;p&gt;b) Estimate the total annual evapotranspiration from this pond in mm.&lt;/p&gt;&#xA;&lt;p&gt;c) The stream in question drains into a Lake of 1000 km2; what is the average percentage of precipitation that falls as snow in this basin (to the nearest 10%)?&lt;/p&gt;&#xA;&lt;p&gt;Thank you for sharing your expertise !&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is how I solve the two first questions&lt;/p&gt;&#xA;&lt;p&gt;a) Volume = P * S&lt;/p&gt;&#xA;&lt;p&gt;b) Water balance equation: P = Q + E&#xA;Then E = P - Q where P in mm and Q in mm&lt;/p&gt;&#xA;&lt;p&gt;c) I don't get the link.&lt;/p&gt;&#xA;" OwnerUserId="24724" LastEditorUserId="24724" LastEditDate="2023-01-25T18:21:28.370" LastActivityDate="2023-01-25T18:21:28.370" Title="How do you determine the % of precipitation falling as snow in the case below?" Tags="|oceanography|hydrology|water|precipitation|snow|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24793" PostTypeId="1" CreationDate="2023-01-25T17:55:37.657" Score="2" ViewCount="88" Body="&lt;p&gt;I asked this question in the Physics SE but it still lies unanswered. Hopefully Earth Science SE is more knowledgeable in the matter.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Lapse_rate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; gives the following equation to calculate the moist adiabatic lapse rate &lt;span class=&quot;math-container&quot;&gt;$\Gamma_w$&lt;/span&gt;, assuming that there is only one condensible gas (water vapour) mixed in the &amp;quot;dry air&amp;quot;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\Gamma_w = g\frac{\left(1+\frac{H_v r}{R_{sd}T} \right)}{\left(c_{pd} + \frac{H_{v}^2r}{R_{sw}T^2} \right)}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$\Gamma_{w}$&lt;/span&gt;: moist adiabatic lapse rate [K/m]&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt;: gravitational acceleration [m/s2]&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$H_{v}$&lt;/span&gt;: latent heat of vaporization of water [J/kg]&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$R_{sd}$&lt;/span&gt;: specific gas constant of dry air [J/kg·K]&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$R_{sw}$&lt;/span&gt;: specific gas constant of water vapour [J/kg·K]&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$r={\frac {\epsilon e}{p-e}}$&lt;/span&gt;: mixing ratio of the mass of water vapour to the mass of dry air&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$\epsilon = \frac{R_{sd}}{R_{sw}}$&lt;/span&gt;: ratio of the specific gas constant of dry air to the specific gas constant for water vapour = 0.622 [dimensionless]&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$e$&lt;/span&gt;: water vapour pressure of the saturated air [Pa]&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$p$&lt;/span&gt;: pressure of the saturated air [Pa]&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt;: temperature of the saturated air [K]&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$c_{pd}$&lt;/span&gt;: specific heat of dry air at constant pressure [J/kg·K]&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;What's the form of this equation when the atmosphere composition differs from Earth's, thus allowing multiple condensible gases or even be entirely composed of only one condensible gas (for example 100% water vapour)?&lt;/p&gt;&#xA;" OwnerUserId="28351" LastEditorUserId="2958" LastEditDate="2023-01-25T19:27:50.433" LastActivityDate="2023-01-25T19:27:50.433" Title="Moist adiabatic lapse rate" Tags="|meteorology|atmosphere|planetary-science|atmosphere-modelling|planetology|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24794" PostTypeId="2" ParentId="24787" CreationDate="2023-01-26T04:12:15.850" Score="10" Body="&lt;p&gt;David Hammen's excellent answer covers the key pieces, but the original question also has this part:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The literal claim (as it appears in headlines) seems to make no sense given a basic understanding of friction and conservation of angular momentum.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This isn't all that simple, actually. What is being conserved is the angular momentum of the Earth as a whole, not of the Earth core in isolation. As a consequence, the Earth's inner core can slow down a little bit if the rest of the Earth accelerates a little bit, and the other way around. Of course there needs to be a torque between the two, but that is not hard to fathom: We &lt;em&gt;know&lt;/em&gt; that the outer core is moving rapidly (on the order of centimeters per second), due to thermal and/or chemical convection, and so it is not hard to imagine that there is friction between inner and outer core.&lt;/p&gt;&#xA;&lt;p&gt;This is not so different from the fact that the solid Earth does not rotate at a fixed rate, but that days are fractions of seconds longer or shorter because the average east-west speed of the atmosphere changes from day to day; because the &lt;em&gt;overall&lt;/em&gt; angular momentum must stay the same, an accelerating atmosphere implies a slowing down solid Earth, and the other way around. The same kind of thing happens (on slightly longer time scales) with ocean currents that take on more or less angular momentum and, as a consequence, have an influence on the rotation rate of the solid earth.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2023-01-26T04:12:15.850" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24795" PostTypeId="1" CreationDate="2023-01-26T10:43:23.007" Score="4" ViewCount="127" Body="&lt;p&gt;I am a 10&lt;sup&gt;th&lt;/sup&gt; grade student and I don't know much about geology but I'm learning about subduction online. It's always mentioned that the denser plate gets subducted under the lesser denser plate. I want to know why it's only the denser plate which gets subducted? I know its buoyancy will be less, but still it's floating over the mantle and when it collides with the lesser denser plate why is it the one which gets subducted, or what &amp;quot;forces&amp;quot; play the role here?&lt;/p&gt;&#xA;" OwnerUserId="28370" LastEditorUserId="2470" LastEditDate="2023-01-26T18:36:58.030" LastActivityDate="2023-09-10T11:06:43.427" Title="What forces plays the role in order to subduct the denser tectonic plate under the lighter plate?" Tags="|geology|plate-tectonics|subduction|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24796" PostTypeId="1" CreationDate="2023-01-26T12:08:05.283" Score="2" ViewCount="55" Body="&lt;p&gt;&lt;strong&gt;Main question:&lt;/strong&gt; What is the highest recorded temperature in degrees of Celsius during the snow/sleet?&lt;/p&gt;&#xA;" OwnerUserId="28372" LastActivityDate="2023-01-26T12:08:05.283" Title="What is the highest recorded temperature on Earth in the place with snowy precipitation?" Tags="|meteorology|" AnswerCount="0" CommentCount="0" ClosedDate="2023-01-27T09:35:00.880" ContentLicense="CC BY-SA 4.0" />
  <row Id="24799" PostTypeId="2" ParentId="24795" CreationDate="2023-01-26T21:51:50.360" Score="0" Body="&lt;p&gt;It is true that due to their chemical composition, oceanic plates (made up largely of basalt) are denser than continental plates (made up largely of granite). As a consequence, when a continental and an oceanic plate meet and push against each other, the oceanic plate generally loses and has to go underneath.&lt;/p&gt;&#xA;&lt;p&gt;This would explain why subducting plates end up under the continents, but not why they actually keep sinking into the mantle. This may be surprising at first because the oceanic plate that is subducting is made up of the same material as the mantle (by and large). But it is much colder than the mantle, and colder generally means denser (with water/ice being the notable exception). This is because the subducting plate has been at the surface for tens of millions of years, cooling in contact with the oceans and the surface. So it is denser, and therefore sinks down in the surrounding mantle. We believe that some subducting plates sink all the way to the bottom of the mantle before they finally achieve temperature equilibrium with the surrounding mantle.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2023-01-26T21:51:50.360" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24800" PostTypeId="1" CreationDate="2023-01-27T03:26:01.120" Score="2" ViewCount="57" Body="&lt;p&gt;I recently realized that I am surrounded by interesting rocks. Having no background in geology nor geologist friends, I rely on online resources to navigate the intriguing stuff I stumble across. But Google lens can only get you so far.&lt;/p&gt;&#xA;&lt;p&gt;I have many questions. The rocks attracting my attention are, I think, mostly intrusive igneous rocks with white and black phenocrysts and/or porphyritic structure. Often there are also shiny metallic bits mixed in (sulfides?).&lt;/p&gt;&#xA;&lt;p&gt;For the present post, I focus on two rocks I found 350 km apart from each other and a difference of 700m in elevation (see attached images). In both of these rocks, it seems to me there are shiny metallic bits among the phenocrysts that have a hexagonal shape. Please have a look at the attached pictures and let me know 1) if you agree that the shiny metallic bits are roughly hexagonal in shape; and 2) what the geological explanation behind the hexagonal shapes might be.&lt;/p&gt;&#xA;&lt;p&gt;The hexagonal metallic shape in the first image is a little above and to the right of the big white rectangular quartz phenocryst. Hexagonal metallic shape number 2 is a little above and to the left of the center of the second image. I took both images using my digital microscope at about 10x-20x magnification.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AQER7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AQER7.png&quot; alt=&quot;first image&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/jGVfF.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jGVfF.jpg&quot; alt=&quot;second image&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28379" LastActivityDate="2023-01-27T03:26:01.120" Title="Hexagonal phenocrysts with a metallic luster?" Tags="|geology|mineralogy|rocks|igneous|hydrothermal-vents|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24801" PostTypeId="2" ParentId="24795" CreationDate="2023-01-27T10:20:25.610" Score="1" Body="&lt;p&gt;Once subduction starts, it tends to keep going because the sinking slab pulls the material behind it. This is &amp;quot;slab pull&amp;quot;, which dominates over &amp;quot;ridge push&amp;quot; at a subduction zone. How subduction starts is an open research question. How subduction continues once started is more or less settled science, so this answer focuses on what happens after subduction has started.&lt;/p&gt;&#xA;&lt;p&gt;The reason the mafic oceanic crust (which is indeed less dense than ultramafic mantle rock) sinks is because at enough depth, the temperature becomes high enough to cook out the portions of the sinking slab with a lower melting point. Basalt and related rock in oceanic crust is a mix of multiple chemicals, some with lower melting points, some with higher melting points. At enough depth, the materials with a lower melting point melts while the materials with a higher melting point remain solid.&lt;/p&gt;&#xA;&lt;p&gt;The materials with a lower melting point also have a lower density than the materials with a higher melting point. The less dense liquid portion of the partial melt rises through the overlying material to form the volcanic arc oftentimes associated with a subduction zone. This is the key process by which much of the continental crust formed.&lt;/p&gt;&#xA;&lt;p&gt;What's left behind in the solid portion of the partial melt is dense ultramafic rock, basically the same chemically as mantle material. As melting is endothermic, the partial melting process cools the remaining solid portion even further. (It was already a bit cooler than the surrounding upper mantle.) That makes it even more dense, denser than the surrounding mantle material, and hence it sinks.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2023-01-27T10:26:22.633" LastActivityDate="2023-01-27T10:26:22.633" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24802" PostTypeId="2" ParentId="24764" CreationDate="2023-01-27T10:30:26.297" Score="1" Body="&lt;p&gt;An analogy: does the high pressure at the bottom of the sea rises the water temperature? No, once you pass the thermocline sea water temperature is pretty much constant, no matter the depth. The oceans are at &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydrostatic_equilibrium&quot; rel=&quot;nofollow noreferrer&quot;&gt;hydrostatic equilibrium&lt;/a&gt;, i.e. the vertical pressure gradient pushing the water upward is balanced by gravitational acceleration. The same goes for the whole planet; actually, being at hydrostatic equilibrium is part of the &lt;a href=&quot;https://www.iau.org/news/pressreleases/detail/iau0603/&quot; rel=&quot;nofollow noreferrer&quot;&gt;updated definition of a planet adopted by the IAU in 2006&lt;/a&gt; (emphasis mine):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The IAU members gathered at the 2006 General Assembly agreed that a&#xA;&amp;quot;planet&amp;quot; is defined as a celestial body that (a) is in orbit around&#xA;the Sun, &lt;em&gt;(b) has sufficient mass for its self-gravity to overcome&#xA;rigid body forces so that it assumes a hydrostatic equilibrium&lt;/em&gt; (nearly&#xA;round) shape, and (c) has cleared the neighbourhood around its orbit.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2023-01-27T10:30:26.297" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24803" PostTypeId="1" CreationDate="2023-01-27T10:46:21.183" Score="3" ViewCount="94" Body="&lt;p&gt;Do all points on the earth surface have with the same longitude the same day and night times, i.e. does the earth rotate around it's own axis with the same speed for all points on the same longitude?&lt;/p&gt;&#xA;" OwnerUserId="28381" LastActivityDate="2023-01-29T21:26:03.100" Title="Earth rotation speed on the same longitude" Tags="|earth-rotation|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24805" PostTypeId="1" CreationDate="2023-01-27T14:47:16.533" Score="2" ViewCount="83" Body="&lt;p&gt;If gigatons of carbon dioxide were taken out of the atmosphere through photosynthesis into long-term soil carbon or tree carbon, or captured from the atmosphere and stored using some kind of technology, would a nearly equivalent amount of carbon dioxide be released into the atmosphere from the surface layers of oceans according to Henry's Law?&lt;/p&gt;&#xA;&lt;p&gt;Bonus question: if the above is correct, why is this almost never part of the discussion of carbon sequestration, which is often imagined as simple subtraction from atmospheric carbon dioxide?&lt;/p&gt;&#xA;" OwnerUserId="28383" LastActivityDate="2023-01-27T15:41:43.957" Title="Carbon &quot;sequestration&quot; or &quot;drawdown&quot; and Henry's Law" Tags="|oceanography|carbon-cycle|carbon-capture|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24806" PostTypeId="2" ParentId="24764" CreationDate="2023-01-27T15:35:51.147" Score="1" Body="&lt;p&gt;Maybe a little, in a way.&lt;/p&gt;&#xA;&lt;p&gt;I was a bit surprised to find this because  the pressure gradient in the mantle actually enhances mantle convection and thus helps remove heat from the Earth.&lt;/p&gt;&#xA;&lt;p&gt;But in the core?&lt;/p&gt;&#xA;&lt;p&gt;In 2003, Kanani Lee and Raymond Jeanloz of UC Berkeley, together with Gerd Steinle-Neumann of the University of Bayreuth, found that at high enough pressures, potassium can form an alloy with iron.&lt;/p&gt;&#xA;&lt;p&gt;This means that during the core differentation process while the Earth was forming, this alloy could have sunk into the core. This would solve the mystery surrounding the relative lack of potassium in the Earth's crust.&lt;/p&gt;&#xA;&lt;p&gt;Some of the potassium would be potassium-40, one of the longest-lived radioactive isotopes, with a half-life of 1.25 billion years. Although much reduced now, the decay of potassium-40 in the potassium-enriched core would have added heat to the core during the Earth's first couple of billion years.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://newsarchive.berkeley.edu/news/media/releases/2003/12/10_heat.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://newsarchive.berkeley.edu/news/media/releases/2003/12/10_heat.shtml&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2004GL019839&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2004GL019839&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6467" LastActivityDate="2023-01-27T15:35:51.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24807" PostTypeId="2" ParentId="24805" CreationDate="2023-01-27T15:41:43.957" Score="2" Body="&lt;p&gt;First off, like many of the other so-called &amp;quot;laws&amp;quot; from the early days of modern chemistry / modern thermodynamics, Henry's Law is an approximate &amp;quot;law&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;More importantly, the goal right now, and for at least the next couple of decades, is to merely reduce the rate at which carbon dioxide is being dumped into the atmosphere. The potential problems that might be associated with a lowering of carbon dioxide levels are problems for a future generation to solve.&lt;/p&gt;&#xA;&lt;p&gt;Finally, it is true that the carbon dioxide dissolved in the oceans will start to come out of solution if carbon dioxide levels in the atmosphere actually do fall, and this will partially (but not completely) offset the reduction in human-generated carbon dioxide. That's a good thing rather than a bad thing. The growing dissolved carbon dioxide levels in the oceans is problematic in and of itself.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-01-27T15:41:43.957" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24808" PostTypeId="2" ParentId="24803" CreationDate="2023-01-27T17:04:44.633" Score="2" Body="&lt;p&gt;You are asking if locations on Earth with the same longitude (East/West position) but different latitude (North/South position) have the same length of day. The answer is no.&lt;/p&gt;&#xA;&lt;p&gt;At the equator, the length of day (from sunrise until sunset) is approximately 12 hours regardless of the time of year. At the northern hemisphere summer solstice, latitudes north of the Artic Circle have 24 hour sunlight. That is, the Sun never sets.&lt;/p&gt;&#xA;&lt;p&gt;Thus, the length of day is dependent on the date and the latitude. The length of the day is not dependent on the longitude. The time of sunrise and sunset depend on the longitude though.&lt;/p&gt;&#xA;" OwnerUserId="19137" LastActivityDate="2023-01-27T17:04:44.633" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24810" PostTypeId="1" CreationDate="2023-01-27T22:55:52.643" Score="2" ViewCount="193" Body="&lt;p&gt;NASA has calculated that the Three Gorges Dam in China dam slows the Earth's rotation by 0.06 microseconds (reference &lt;a href=&quot;https://www.kinetica.co.uk/2014/03/27/chinese-dam-slows-down-earths-rotation/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.kinetica.co.uk/2014/03/27/chinese-dam-slows-down-earths-rotation/&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;Has extracting oil and mining changed the Earth's rotational speed?&lt;/p&gt;&#xA;" OwnerUserId="28391" LastActivityDate="2023-01-29T00:49:39.710" Title="Has extracting oil and mining changed the earth rotational speed?" Tags="|earth-rotation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24811" PostTypeId="1" AcceptedAnswerId="24816" CreationDate="2023-01-28T11:43:37.247" Score="10" ViewCount="173" Body="&lt;p&gt;Earth's total land area has increased throughout its history according to &lt;a href=&quot;https://www.youtube.com/watch?v=ovT90wYrVk4&quot; rel=&quot;noreferrer&quot;&gt;this video&lt;/a&gt;. What is the dependence of the total area of continents from time?&lt;/p&gt;&#xA;" OwnerUserId="28394" LastEditorUserId="6467" LastEditDate="2023-01-28T23:28:45.647" LastActivityDate="2023-01-29T14:18:47.740" Title="How has the total area of continents changed during the Earth history?" Tags="|geology|earth-history|paleogeography|continent|continental-crust|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24812" PostTypeId="2" ParentId="24811" CreationDate="2023-01-28T20:44:44.467" Score="4" Body="&lt;p&gt;It is widely thought that when the Earth first formed there was no continental crust. Subduction is largely responsible for the creation of continental crust. If true, and there is no reason to think this is not true, continental crust has grown from nearly zero percent of the planet &lt;a href=&quot;https://www.sciencenews.org/article/earth-plate-tectonics-may-have-started-earlier-than-we-thought&quot; rel=&quot;nofollow noreferrer&quot;&gt;over three billion or so years ago&lt;/a&gt; to covering about 30% of the planet today.&lt;/p&gt;&#xA;&lt;p&gt;Continental crust is subject to erosion. As ever more continental crust formed, progressively more of it eroded and washed to sea. Most geologists think the formation of new crust and degradation of old crust have long been in balance.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2023-01-28T20:55:52.717" LastActivityDate="2023-01-28T20:55:52.717" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24813" PostTypeId="1" CreationDate="2023-01-28T20:46:02.257" Score="1" ViewCount="26" Body="&lt;p&gt;One of the fundamental principles in fluid mechanics is the conservation of mass - how is this treated in integrated surface water | groundwater models such as MIKE models, say between two river cross-sections?&lt;/p&gt;&#xA;" OwnerUserId="27888" LastActivityDate="2023-01-28T20:46:02.257" Title="Conservation of mass in Integrated surface water and groundwater models" Tags="|hydrology|numerical-modelling|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24814" PostTypeId="2" ParentId="24810" CreationDate="2023-01-28T20:46:10.630" Score="2" Body="&lt;p&gt;The capacity of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Three_Gorges_Dam&quot; rel=&quot;nofollow noreferrer&quot;&gt;Three Gorges Dam&lt;/a&gt; is 39.3 km&lt;sup&gt;3&lt;/sup&gt;, or 39.3 × 10&lt;sup&gt;9&lt;/sup&gt; m&lt;sup&gt;3&lt;/sup&gt;. One cubic meter of water has a mass of 1 tonne, so the capacity of the dam is 39.3 billion tonnes of water (billion as recognized in the USA). From here onward I use billion as it is used in the USA, 1 followed by nine zeros (10&lt;sup&gt;9&lt;/sup&gt;).&lt;/p&gt;&#xA;&lt;p&gt;The Three Gorges Dam is situated in one small location, relatively speaking. Mine production occurs at various locations around the world, so there will be a countering affect because of this.&lt;/p&gt;&#xA;&lt;p&gt;Considering the mining aspect, the two main commodities that are mined in bulk quantities are &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_countries_by_iron_ore_production&quot; rel=&quot;nofollow noreferrer&quot;&gt;iron ore&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_countries_by_coal_production&quot; rel=&quot;nofollow noreferrer&quot;&gt;coal&lt;/a&gt;. The total world annual production of iron ore is 2.5 billion tonnes. The total annual amount of coal mined is 7.7416 billion tonnes.&lt;/p&gt;&#xA;&lt;p&gt;Combined with iron ore production, that amounts to 10.2416 billion tonnes of iron ore and coal in one year. This is 26 percent the capacity of the Three Gorges Dam.&lt;/p&gt;&#xA;&lt;p&gt;The total amount of &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_countries_by_oil_production&quot; rel=&quot;nofollow noreferrer&quot;&gt;crude oil&lt;/a&gt; produced in the world in 2021 was 77,043,680 barrels per day, which is 28.1396 billion barrels, or  4.476  billion cubic meters for that year. Taking a &lt;a href=&quot;https://www.engineeringtoolbox.com/crude-lubricant-lubricating-oil-density-temperature-gravity-volume-correction-ASTM-D1250-d_1938.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;density for crude&lt;/a&gt; oil as 900 kg/m&lt;sup&gt;3&lt;/sup&gt; (0.9 t/m&lt;sup&gt;3&lt;/sup&gt;), &lt;a href=&quot;https://www.metric-conversions.org/volume/us-oil-barrels-to-cubic-meters.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;this equates to&lt;/a&gt; 4.0284 billion tonnes of crude oil.&lt;/p&gt;&#xA;&lt;p&gt;Add this to the amounts for iron ore and coal and the total is 14.27 billion tonnes extracted in one year. This amounts to 36.3 percent of the capacity of the Three Gorges Dam.&lt;/p&gt;&#xA;&lt;p&gt;As mentioned previously, the Three Gorges Dam is located in relatively small area of the world. Mine and oil extraction occurs around the planet. There will be an effect from such mining and oil extraction activities, but the effect will be much less.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2023-01-29T00:49:39.710" LastActivityDate="2023-01-29T00:49:39.710" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24815" PostTypeId="2" ParentId="24803" CreationDate="2023-01-29T09:37:30.270" Score="3" Body="&lt;p&gt;It is not as simple as Earth axis is not normal to our rotation plane around the Sun (ecliptic).&#xA;Earth axis is tilted 23.4 degres (aprox):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/G4MQR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G4MQR.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Sunlight impact to Earth parallel (aprox) to the ecliptic, but our rotation axis is tilted. It seems that everypoint at the same meridian should have same daylight, but depends on lattitude. According to the figure above, someone at Venezuela should have same daylight that someone at Labrador (Canada), as they are in the same meridian.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/C6cV7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/C6cV7.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But the fact is that, due to this tilting, they are not transitting the same time:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9RgOP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9RgOP.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Point at a higher lattitude (Canada), in this case, it is exposed less time to the sun due to Earth tilting. This figure will be at North Hemisphere winter. Yellow line is representing path exposed to sunlight and light blue is path not exposed to sunlight.&lt;/p&gt;&#xA;&lt;p&gt;This is a simple representation not considering Earth atmosphere. If we consider Earth atmosphere, everything is a little bit more complicated, as there are different dawn times. Check this link: &lt;a href=&quot;https://en.wikipedia.org/wiki/Dawn&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Dawn&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;With the same example, today daylight looks like:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vdtSZ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vdtSZ.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Hope it helps!&lt;/p&gt;&#xA;" OwnerUserId="18035" LastActivityDate="2023-01-29T09:37:30.270" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24816" PostTypeId="2" ParentId="24811" CreationDate="2023-01-29T14:18:47.740" Score="7" Body="&lt;p&gt;I think the question is asking about the trend, i.e., how did we get from zero continental crust to about 30 % over the Earth's history? Was it linear, another trend? Well, one figure is enough to show that we don't know:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ofqnX.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ofqnX.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;em&gt;Selected crustal growth models, from &lt;a href=&quot;https://doi.org/10.1016/j.gsf.2018.02.004&quot; rel=&quot;noreferrer&quot;&gt;Hawkesworth et al. (2019)&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Some think all continental crust formed early in Earth history, and nothing since then, others think it was more progressive, proposing very different trends...&lt;/p&gt;&#xA;&lt;p&gt;One classical way to infer crustal growth is by dating zircons, a very resistant mineral that is used to infer the presence of rocks that are themselves long gone. It's been known for a while that zircons present some age peaks across Earth's history, but their are some disagreements on the interpretation. From &lt;a href=&quot;https://doi.org/10.1130/GES01361.1&quot; rel=&quot;noreferrer&quot;&gt;Condie et al. (2017)&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;There is an ongoing debate about the interpretation of zircon age&#xA;peaks in igneous rocks and detrital sediments (Rino et al., 2004;&#xA;Arndt and Davaille, 2013; Hawkesworth et al., 2013). The conventional&#xA;interpretation is that the age peaks correspond to peaks in production&#xA;of new continental crust extracted from the mantle (Stein and Hofmann,&#xA;1994; Condie, 1998; Albarède, 1998). However, this interpretation has&#xA;been challenged by advocates of recycling and preservation models;&#xA;they propose that the peaks record periods of enhanced preservation of&#xA;crust during the assembly of supercontinents (Condie and Aster, 2009,&#xA;2010; Hawkesworth et al., 2010; Voice et al., 2011).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In summary, it is a hot research topic which is still very much debated. If someone has the answer here at Stack Exchange, he/she should apply for the Penrose medal! :)&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2023-01-29T14:18:47.740" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24817" PostTypeId="1" AcceptedAnswerId="24823" CreationDate="2023-01-29T15:32:01.713" Score="17" ViewCount="5046" Body="&lt;p&gt;So I was in this place called &lt;a href=&quot;https://goo.gl/maps/ZT5TV4f36347xArS7&quot; rel=&quot;noreferrer&quot;&gt;Chamundi hills, Mysore&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I was riding back at around 7pm down hill and noticed this strange behavior. About every 50-100 meters the temperature fluctuated.&lt;/p&gt;&#xA;&lt;p&gt;It was extremely cold in some areas and in the next 100 meters I could feel the warmth. The whole cycle repeated all the way (about 8-10 kilometers).&lt;/p&gt;&#xA;&lt;p&gt;Is there any scientific explanation about this?&lt;/p&gt;&#xA;" OwnerUserId="28399" LastActivityDate="2023-01-31T03:14:01.810" Title="Why does the temperature change about every 50-100 meters near hills" Tags="|meteorology|temperature|" AnswerCount="4" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="24818" PostTypeId="2" ParentId="24817" CreationDate="2023-01-29T15:52:52.607" Score="9" Body="&lt;p&gt;I assume local downstream flows of cold air near surface, that got cool down by surface radiation on the hill slopes. You can imagine it as invisible rivers of cold, descending air.&lt;/p&gt;&#xA;" OwnerUserId="21346" LastActivityDate="2023-01-29T15:52:52.607" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24820" PostTypeId="1" CreationDate="2023-01-29T22:43:41.150" Score="2" ViewCount="66" Body="&lt;p&gt;It seems to me that not much attention is given to meteorology these days. I am wondering if this is because it is an almost &amp;quot;solved&amp;quot; science in terms of what could be possibly known and predicted. So, what are the next breakthroughs awaiting for meteorology and in general climate science?&lt;/p&gt;&#xA;" OwnerUserId="28351" LastActivityDate="2023-01-29T22:43:41.150" Title="What are the next meteorology breakthroughs?" Tags="|meteorology|climate|" AnswerCount="0" CommentCount="6" ClosedDate="2023-01-30T08:07:02.097" ContentLicense="CC BY-SA 4.0" />
  <row Id="24821" PostTypeId="1" CreationDate="2023-01-30T00:34:19.043" Score="3" ViewCount="134" Body="&lt;p&gt;Its normally said that deserts cool planets because they reflect more radiation back to space. According to this logic if all the land mass in the world was desert the world should be colder.&#xA;Is it true that the average temperature of a desert is higher than green land in a similar climate?  If so wouldnt the average surface temperature be higher if all the world was a desert? And if so how can we still claim deserts cool the earth? Isnt the metric of whether we have global warming, the average surface temperature?&lt;/p&gt;&#xA;" OwnerUserId="26557" LastActivityDate="2023-01-30T11:13:22.067" Title="If all land mass was desert would the world be hotter or colder than it is now?" Tags="|climate|desert|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24822" PostTypeId="2" ParentId="12106" CreationDate="2023-01-30T06:15:20.653" Score="1" Body="&lt;p&gt;It would depend more on the frequency more than the magnitude, and whether the building has a damper weight, like the Taipei Tower, which is tuned to swing in the opposite direction if the building resonates, in which case, you would feel it more at the bottom, because the building would flex and absorb the movement, the same as if it was not at resonance. But if it was, and there was no damper, you would feel it more at the top, at least until the building collapsed.☹️ The damper weight works like a ball on a string. When you move your hand at it's resonant frequency, it will swing much wider than your hand movement. If you increase the frequency slightly, it will swing the opposite way. It it is called anti resonance. The force on the steel cables pulls on the building the opposite way to which it is swaying, greatly reducing the sway.&lt;/p&gt;&#xA;" OwnerUserId="28401" LastEditorUserId="28401" LastEditDate="2023-02-09T02:08:29.787" LastActivityDate="2023-02-09T02:08:29.787" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24823" PostTypeId="2" ParentId="24817" CreationDate="2023-01-30T09:13:15.757" Score="30" Body="&lt;p&gt;To extend @Poutnik's invisible river analogy, the cold air can also 'pool' in small dips.&lt;/p&gt;&#xA;&lt;p&gt;On clear nights,  temperature fluctuations are quite a frequent occurrence due to radiative cooling. If the air cools sufficiently to reach the dew point, then cloud can act as a 'tracer' for the air pockets.&lt;/p&gt;&#xA;&lt;p&gt;An example of this are fog patches that you potentially pass through in certain conditions. The air in the fog patches is a little colder (or higher absolute humidity, for example over a lake) than the surrounding fog-free areas. Even if the air wasn't cold enough to form cloud, the same temperature variation can occur invisibly.&lt;/p&gt;&#xA;&lt;p&gt;Here's an example from &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Morning_fog_over_Keravanjoki_river_in_Vantaa,_Finland,_2021_October_-_4.jpg&quot; rel=&quot;noreferrer&quot;&gt;Wikimedia user Simo Räsänen&lt;/a&gt;:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/FPRUI.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FPRUI.png&quot; alt=&quot;Radiation fog over flat fields and pond in morning&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;In the mountains, the invisible rivers of cold, descending air that @Poutnik mentions can sometimes be seen by tracer clouds flowing down hillsides. Colder air is denser than the surrounding air and has less friction so gravity pulls it down. The areas with cloud will be colder than the adjacent cloud-free zones. This effect can lead to strong down-slope &lt;a href=&quot;https://en.wikipedia.org/wiki/Katabatic_wind&quot; rel=&quot;noreferrer&quot;&gt;katabatic winds&lt;/a&gt;. In Antarctica this effect is responsible for some of the strongest winds in the world.&lt;/p&gt;&#xA;&lt;p&gt;Here's a good example from &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:%D7%9E%D7%9B%D7%AA%D7%A9_%D7%A8%D7%9E%D7%95%D7%9F_-_%D7%92%D7%9C%D7%99%D7%A9%D7%AA_%D7%A2%D7%A0%D7%A0%D7%99%D7%9D_(cropped).jpg&quot; rel=&quot;noreferrer&quot;&gt;Wikimedia user Andrew J. Kurbiko&lt;/a&gt;:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/rlH7H.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rlH7H.png&quot; alt=&quot;Radiation fog tracing katabatic winds off a plateau&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;To summarise, the key to the effect you noticed is almost certainly &lt;a href=&quot;https://en.wikipedia.org/wiki/Radiative_cooling&quot; rel=&quot;noreferrer&quot;&gt;radiative cooling&lt;/a&gt; and the movement of colder denser air. Radiative cooling occurs due to any object above absolute zero giving off radiation. On a clear night this radiation passes through the Earth's atmosphere and is lost into space. This cools down the object (land) that the radiation came from. The land, in turn, cools down the air above it. On a cloudy night, the radiation is reflected by the clouds and reabsorbed by the land keeping the temperature constant.&lt;/p&gt;&#xA;" OwnerUserId="20542" LastActivityDate="2023-01-30T09:13:15.757" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="24824" PostTypeId="2" ParentId="24821" CreationDate="2023-01-30T11:01:13.040" Score="1" Body="&lt;p&gt;Water vapor is a powerful greenhouse gas. The key characteristic of a desert is lack of precipitation, and that is typically correlated with a low humidity. That reduced humidity means more thermal infrared radiation going from the Earth's surface to space.&lt;/p&gt;&#xA;&lt;p&gt;Desert doesn't necessarily mean hot. A place is qualified as a desert if it has very reduced precipitation. The Atacama Desert, one of the (if not the) driest places on the planet, can get quite cold. Almost all of Antarctica is technically a desert, and it is very cold. At the height of the last glaciation, much of the northern portion of the Northern Hemisphere was technically a desert, and it too was very cold.&lt;/p&gt;&#xA;&lt;p&gt;On the flip side, a billion years or so from now, the Earth is predicted to go through a warm greenhouse phase due to the Sun getting more luminous. The oceans will evaporate, some water will be split into hydrogen and oxygen, and eventually the hydrogen will escape into space. At that point, the entire Earth will technically be a desert as there will be no water anywhere, and it probably will be hot.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-01-30T11:01:13.040" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24825" PostTypeId="2" ParentId="24821" CreationDate="2023-01-30T11:13:22.067" Score="0" Body="&lt;h1&gt;Blisteringly hot at day, freezing cold at night&lt;/h1&gt;&#xA;&lt;p&gt;Assuming that &amp;quot;deserts&amp;quot; here mean sandy places with extremely dry air, then it will get really hot at day, but freeze over at night.&lt;/p&gt;&#xA;&lt;p&gt;Deserts, which are mostly made up of sand (excluding a few places of bare rock and stuff), tend to act like mirrors. Sand has an extremely low specific heat capacity i.e. it heats up quickly with much less energy, but also cools down really quickly. Sand also has a really high albedo i.e. it is very reflective, so it tends to reflect away sunlight. Dry sand also has the nasty habit of &lt;a href=&quot;https://www.google.com/url?sa=t&amp;amp;source=web&amp;amp;rct=j&amp;amp;url=https://ui.adsabs.harvard.edu/abs/2017AGUFMED11D0156N/abstract%23:%7E:text%3DDry%2520sand%2520reflects%2520infrared%2520radiation,wet%2520sand%2520absorbs%2520IR%2520radiation.&amp;amp;ved=2ahUKEwikyZ2Aj-_8AhW76nMBHWETAfoQFnoECA0QBQ&amp;amp;usg=AOvVaw1a125rqYW9hziab7GojV64&quot; rel=&quot;nofollow noreferrer&quot;&gt;reflecting away infrared&lt;/a&gt; (wet sand, on the other hand absorbs IR). This gets even worse, as desert air is generally extremely dry, with no water. If it had been humid air, there would atleast have been a &lt;a href=&quot;https://www.google.com/url?sa=t&amp;amp;source=web&amp;amp;rct=j&amp;amp;url=https://physics.stackexchange.com/questions/45349/how-air-humidity-affects-how-much-time-is-needed-for-heating-the-air%23:%7E:text%3DSo%2520the%2520specific%2520heat%2520capacity,the%2520difference%2520is%2520quite%2520small.&amp;amp;ved=2ahUKEwixvdqxj-_8AhX1mOYKHe3IDg0QFnoECA0QBQ&amp;amp;usg=AOvVaw2l58JGUCALzg8cCbdwZ4uH&quot; rel=&quot;nofollow noreferrer&quot;&gt;chance of water absorbing this heat and thus reducing the temperature&lt;/a&gt; (Water has a extremely high specific heat, second to only hydrogen). But with no water vapour, there is nothing to absorb the heat.&lt;/p&gt;&#xA;&lt;p&gt;Assuming that we switched Earth's entire surface with just sand and a few areas of exposed rock, Earth would look like Mercury on steroids. The dayside would get ridiculously hot, perhaps hundreds of degrees, as the sand reflects infrared and visible light back into the air, heating it up rapidly. However, since sand has an extremely low specific heat capacity, it will rapidly cool, once daytime has ended. At night, the temperatures may plummet to below freezing, as the sand quickly releases its heat away.&lt;/p&gt;&#xA;&lt;p&gt;TlDr Blisteringly hot at day, but freezing cold at night&lt;/p&gt;&#xA;" OwnerUserId="27863" LastActivityDate="2023-01-30T11:13:22.067" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24826" PostTypeId="2" ParentId="24265" CreationDate="2023-01-30T11:26:29.317" Score="2" Body="&lt;p&gt;To add more detail to @Andy M's answer and your subsequent question in the comment:&lt;/p&gt;&#xA;&lt;p&gt;Canada is much closer to the wet USA and there is no ocean in between. Ice doesn't have to correlate with the precipitation. Areas where there is precipitation will form the ice. When it gets thick enough the ice will flow under its own weight outwards from the centre, perhaps a long distance (this is the definition of a ice sheet/ice cap). A deep sea will interrupt the process as floating ice shelves act differently to land-supported ice.&lt;/p&gt;&#xA;" OwnerUserId="20542" LastActivityDate="2023-01-30T11:26:29.317" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24827" PostTypeId="2" ParentId="24817" CreationDate="2023-01-30T14:50:56.640" Score="4" Body="&lt;p&gt;Yes, there could be several reasons for the temperature fluctuation you experienced. Some possible explanations are:&lt;/p&gt;&#xA;&lt;p&gt;Altitude change: As you were riding downhill, you may have experienced changes in altitude, which can affect temperature.&lt;/p&gt;&#xA;&lt;p&gt;Microclimates: Different areas of the hill may have their own microclimates, with different temperatures and humidity levels, which could explain the fluctuations you experienced.&lt;/p&gt;&#xA;&lt;p&gt;Air currents: The movement of air currents can also cause temperature fluctuations, as warm air rises and cold air sinks.&lt;/p&gt;&#xA;&lt;p&gt;Shadows: Shadows cast by buildings, trees, or other obstacles can also affect temperature, as they can block the sun's warmth.&lt;/p&gt;&#xA;&lt;p&gt;Localized heating: Localized heating sources, such as factories or power plants, can also affect temperature in a specific area.&lt;/p&gt;&#xA;&lt;p&gt;It's possible that a combination of these factors contributed to the temperature fluctuations you experienced.&lt;/p&gt;&#xA;" OwnerUserId="28402" LastActivityDate="2023-01-30T14:50:56.640" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24828" PostTypeId="2" ParentId="24817" CreationDate="2023-01-31T03:14:01.810" Score="2" Body="&lt;p&gt;Something I have observed more than once:  Katabatic and anabatic winds tend to follow drainage patterns--there's more air flow when you're lined up with the terrain.  Even when you don't feel the wind it can change the air temperature.&lt;/p&gt;&#xA;" OwnerUserId="1160" LastActivityDate="2023-01-31T03:14:01.810" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24829" PostTypeId="2" ParentId="17705" CreationDate="2023-01-31T05:26:58.733" Score="1" Body="&lt;p&gt;I'd say not simple. Check out my diagram below.&lt;a href=&quot;https://i.stack.imgur.com/8fVWe.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8fVWe.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;If you want to simulate a tall building, I would suggest using a long wooden dowel or thin board, rigidly anchored to a movable base or fairly long metal lever, and move the base (or lever). You could video it at the fundamental and harmonic frequencies, then, playing it back on still frame, count the number of frames per cycle to determine which harmonic(s) it resonates at.&lt;/p&gt;&#xA;" OwnerUserId="28401" LastEditorUserId="28401" LastEditDate="2023-02-20T03:58:36.533" LastActivityDate="2023-02-20T03:58:36.533" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24830" PostTypeId="2" ParentId="20171" CreationDate="2023-01-31T14:12:33.737" Score="3" Body="&lt;p&gt;Could the answer be that the temperature falls at night compared to what it was during the day? It is unlikely to stay the same temperature during the day and night on a regular basis. The drop of temperature would increase the relative humidity, compared to the day, and so it will feel 'muggier' at night, which might lead to you thinking it feels hotter. The vague idea I'm proposing is that the '&lt;a href=&quot;https://www.weather.gov/ama/heatindex&quot; rel=&quot;nofollow noreferrer&quot;&gt;heat index&lt;/a&gt;' increases at night or at least stays similar. Your brain may then expect it to feel cooler at night and so notice the heat more.&lt;/p&gt;&#xA;&lt;p&gt;For example if it's 90°F and 55% humidity then the heat index is 97°F. If at night these readings change to 84°F and 90% humidity the heat index would be 98°F. Combined with the psychological effect of expecting it to be cooler at night may account for your experience? (I just plucked those numbers to give an example of the effect I am mention. The change of relative humidity for a 6°F temperature change is probably wrong.)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bkLeA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bkLeA.png&quot; alt=&quot;Heat index chart from weather.gov. Public domain image as it's US Government copyright.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20542" LastEditorUserId="20542" LastEditDate="2023-02-01T13:59:03.283" LastActivityDate="2023-02-01T13:59:03.283" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24831" PostTypeId="1" CreationDate="2023-02-01T05:54:08.740" Score="1" ViewCount="31" Body="&lt;p&gt;A program I'm writing does the following:&#xA;(EQ=earthquake, EV=event, ML=machinelearning, etc)&lt;br/&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;from a time series (in a selected station) it picks pairs of EQ' EVs with similar characteristics (magnitude/depth)&lt;/li&gt;&#xA;&lt;li&gt;from pairs, depth, magnitude it calculates individual force  for each of EV,&lt;/li&gt;&#xA;&lt;li&gt;for individual force, (with or without multiple stations added properties) it determines an approximate mass.&#xA;&lt;br/&gt;&#xA;&lt;br/&gt;&#xA;We run this (simple and not too nested) pandas. Then how can we calculate the mechanical/kinetic entropy of EVs to add to pair properties for our algorithm evaluation?&#xA;&lt;br/&gt;&#xA;&lt;br/&gt;&#xA;The model finally creates pairs clusters as single events (time independence) within the matching algorithm.&lt;br/&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Are there any similar algorithms used for Earthquakes modelling?&lt;/p&gt;&#xA;" OwnerUserId="28412" LastEditorUserId="28412" LastEditDate="2023-02-18T05:21:58.413" LastActivityDate="2023-02-18T05:21:58.413" Title="Earthquake clustering by pairs algorithm questions" Tags="|oceanography|models|hydrogeology|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24832" PostTypeId="1" CreationDate="2023-02-01T08:25:48.147" Score="9" ViewCount="119" Body="&lt;p&gt;I was reading some articles on Jupiter, when I stumbled across &lt;a href=&quot;https://edition.cnn.com/2016/07/28/health/jupiter-great-red-spot-heat/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt;, which said that the Great Red Spot makes the upper atmosphere really, really hot. As in &amp;quot;hotter-than-lava&amp;quot;. This apparently occured due to large sound waves and atmospheric gravity waves (not gravitational waves), produced when large pockets of air collided, producing immense turbulence, that sent atoms into the upper atmosphere and heating it up:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The huge storm emits large sound waves and atmospheric gravity waves –&#xA;created when large pockets of air collide – with huge amounts of&#xA;kinetic energy, sending atoms flying around and raising the&#xA;temperature of the atmosphere above the Spot.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/45MQ7.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/45MQ7.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, I didn't come here to ask about Jupiter's Great Red Spot or anything astronomical. This information is not going to be a actual part of the question, as the information above merely suggests where I got this idea from. The article simply poked my curiosity for atmospheric physics. However let's move onto the real question.&lt;/p&gt;&#xA;&lt;p&gt;On Earth, we do have large storms. Well not planet-sized storms, but storms the size of entire countries. Typhoon Tip, for example, reached more than 2,000 km in diameter. Typhoon Tip also, was an incredibly turbulent environment, with air pockets colliding. Also, lightning and immense winds could have produced immense sound waves that could have scattered atoms away, and heated up the upper atmosphere to scorching temperatures. It's not just restricted to Typhoon Tip, other energetic hurricanes, like Katrina, Patricia etc. were extremely energetic hurricanes that could have produced sound waves and enough turbulence to heat up the upper atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;Aside from hurricanes, there are also a plethora of extremely turbulent phenomenon on Earth, such as supercells, derechos, squall lines and so on. These environments have a lot of wind shear, fast winds, updrafts and downdrafts, which have a knack for producing intense turbulence. Rain and hailstones colliding with each other, lightning forming, should produce enough sound and turbulence to heat up the upper atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;Yet this phenomenon does not occur on Earth. Earth's upper atmosphere is really, really cold, excluding the thermosphere, which is indeed scorching hot, but is diffuse and evenly heated, unlike on Jupiter, where storms heat up the areas of the upper atmosphere above them.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Why don't terrestrial storms heat up the upper atmosphere?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="27863" LastEditorUserId="27863" LastEditDate="2023-02-04T08:46:35.153" LastActivityDate="2023-02-04T08:46:35.153" Title="Why don't terrestrial storms heat up the upper atmosphere?" Tags="|atmosphere|tropical-cyclone|storms|turbulence|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24833" PostTypeId="1" CreationDate="2023-02-01T15:36:27.660" Score="4" ViewCount="87" Body="&lt;p&gt;Why are Hadley cells not symmetrical?&lt;/p&gt;&#xA;&lt;p&gt;For example, during summer in the northern hemisphere, the Hadley cell in the Northern hemisphere is significantly weaker than the one in the Southern Hemisphere.&lt;/p&gt;&#xA;&lt;p&gt;I've been told that the southern hemisphere Hadley cell plays a row to carry energy from the SH to the NH in the lower troposphere (elevation) whereas in the upper elevation, energy travels from the summer hemisphere to the winter hemisphere.&lt;/p&gt;&#xA;&lt;p&gt;What are these differences and what is the concept behind it?&lt;/p&gt;&#xA;" OwnerUserId="28416" LastEditorUserId="2958" LastEditDate="2023-02-02T07:34:37.410" LastActivityDate="2023-02-02T07:34:37.410" Title="Why are Hadley cells not symmetrical?" Tags="|atmosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24834" PostTypeId="2" ParentId="24833" CreationDate="2023-02-01T16:30:56.657" Score="3" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;I've been told that the southern hemisphere hadley cell play a row to carry energy from the SH to the NH in the lower troposphere (elevation) whereas in the upper elevation, energy travel from the summer hemisphere to the winter hemisphere.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In a way, the Earth has two atmospheres, a Northern Hemisphere atmosphere and a Southern Hemisphere atmosphere. There is some mixing (and hence energy transfer) between them, but it's not a whole lot -- and the net energy transfer is from the Northern Hemisphere to the Southern Hemisphere.&lt;/p&gt;&#xA;&lt;p&gt;The much greater energy transfer in which the Hadley cells participate is from equatorial regions to polar regions rather than from one hemisphere to the other. As the temperature gradient between equatorial regions and a polar region is much greater in winter than in summer, the Northern Hemisphere Hadley cell is more active in Northern Hemisphere winter than it is in the summer. The same goes for the Southern Hemisphere Hadley cell, except of course that the south's winter is the north's summer, and vice versa.&lt;/p&gt;&#xA;&lt;p&gt;One key difference between the two hemispheres is that the Northern Hemisphere has a lot more land area than does the Southern Hemisphere. This makes the Northern Hemisphere warmer than the Southern Hemisphere, on average. It also makes the Northern Hemisphere more volatile, at least over land. On average, Northern Hemisphere summers are warmer than are Southern Hemisphere summers, while Northern Hemisphere winters are colder than are Southern Hemisphere winters. This is despite the fact that Northern Hemisphere winter and Southern Hemisphere summer occurs when the Earth is closest to the Sun, and vice versa for when the Earth is furthest from the Sun.&lt;/p&gt;&#xA;&lt;p&gt;Another key difference is that the North Pole is in the middle of a small ocean that is almost entirely surrounded by land while the South Pole is in the middle of a continent that is completely surrounded by a not so small Southern Ocean. This difference again plays a role in the difference between the climates of this two hemisphere.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Why are the Hadley cells not symmetrical?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;With all of these differences (seasons, land distribution, and the nature of the poles) between the two hemispheres, it would be very surprising if the Hadley cells were symmetrical. Not so surprisingly, they're a bit different.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2023-02-01T16:45:03.300" LastActivityDate="2023-02-01T16:45:03.300" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24835" PostTypeId="2" ParentId="20171" CreationDate="2023-02-02T00:18:29.033" Score="2" Body="&lt;h2&gt;Because you are actually hotter.&lt;/h2&gt;&#xA;&lt;p&gt;Body temperature changes fairly predictably though the day and varies by several degrees.&lt;/p&gt;&#xA;&lt;p&gt;Your body temperature is highest a few hours before you go to bed (assuming a normal diurnal work schedule). It drops through the night which is why you often feel coldest in the early morning. this pops up a lot in sleep studies since people often feel like they don't need a blanket when they go to sleep and wake up in the early morning desperately wanting one.&lt;/p&gt;&#xA;&lt;p&gt;If you are a little warm during the day you are going to be very warm later in the day crawling into a well insulated bed reflecting a lot of that heat back, but may well wake up feeling cold.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EDKXi.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EDKXi.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Human_body_temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Human_body_temperature&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7678948/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7678948/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2023-02-02T00:23:29.930" LastActivityDate="2023-02-02T00:23:29.930" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24836" PostTypeId="2" ParentId="20171" CreationDate="2023-02-03T02:29:49.060" Score="2" Body="&lt;p&gt;Assuming you are talking about the sensed temperature outdoors...&lt;/p&gt;&#xA;&lt;p&gt;Solar heating of the surface creates circulations at various scales. One example is a seabreeze, which occurs due to differential heating between land and water and can occur at any scale.&lt;/p&gt;&#xA;&lt;p&gt;So winds are generally stronger during the day. As the wind blows across your body, heat is removed from you and given to the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;Generally stronger winds during the day leads to more heat loss from the body for a given air temperature.&lt;/p&gt;&#xA;" OwnerUserId="28422" LastEditorUserId="28422" LastEditDate="2023-02-03T02:33:43.980" LastActivityDate="2023-02-03T02:33:43.980" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24839" PostTypeId="2" ParentId="22740" CreationDate="2023-02-03T14:07:06.430" Score="1" Body="&lt;p&gt;This is what I found on Wiki, researching the same question:&#xA;The isthmus of Panama is thought to have been formed around 3 million years ago, separating the Atlantic and Pacific Oceans and causing the creation of the Gulf Stream. This was first suggested in 1910 by North American paleontologist Henry Fairfield Osborn. He based the proposal on the fossil record of mammals in Central America. This conclusion provided a foundation for Alfred Wegener when he proposed the theory of continental drift in 1912.&#xA;What now bugs me is the outline of sea/oceanic currents before the isthmus closed.&lt;/p&gt;&#xA;" OwnerUserId="28427" LastActivityDate="2023-02-03T14:07:06.430" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24840" PostTypeId="2" ParentId="24832" CreationDate="2023-02-03T15:12:49.117" Score="4" Body="&lt;p&gt;It's first important to distinguish what you mean by the upper atmosphere. Weather occurs in the troposphere. The tropopause (boundary between troposphere and stratosphere, which is a dynamic boundary) generally prevents mixing between the two lower layers of the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;Meteorologists generally think of the upper atmosphere as upper layers in the troposphere, usually looking at information up to the 250mb pressure surface level, where the jet streams typically exist. In this sense, both tropical cyclones (which are more like heat engines) pump heat from the surface upwards into this upper atmosphere. The same goes for extratropical cyclones (frontal systems) in which cold air pushes underneath warm air, lifting the warmer air mass.&lt;/p&gt;&#xA;&lt;p&gt;In both of these cases, heat is moved upwards, but it is free to radiate to space at the upper levels of the troposphere because the atmosphere above the tropopause is almost entirely transparent to infrared radiation. As far as the upper troposphere is concerned, infrared radiation is constantly escaping to space while atmospheric motions are also moving heat up and down through the troposphere. All infrared radiation at the surface of Earth attempts to escape to space. Greenhouse gases and clouds primarily slow down/prevent the escape of some of this radiation. That is why greenhouse gases (in appropriate concentrations) are necessary for life on Earth, without them, all the infrared radiation would escape to space and Earth would be unbearably cold.&lt;/p&gt;&#xA;&lt;p&gt;The chemical composition at a given level in any planetary atmosphere determines how solar and terrestrial radiation will be &amp;quot;handled.&amp;quot; On Earth, the ozone layer in the stratosphere interacts strongly with certain wavelengths of UV radiation, but not IR radiation. On other planets like Jupiter and Venus, there are gaseous compositions at upper levels of the atmospheres that may interact more strongly with IR radiation. Or, as you mentioned, may be heated by friction due to other forms of energy transfer.&lt;/p&gt;&#xA;&lt;p&gt;Info on tropical cyclones: &lt;a href=&quot;https://www.noaa.gov/jetstream/tropical/tropical-cyclone-introduction&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.noaa.gov/jetstream/tropical/tropical-cyclone-introduction&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28422" LastEditorUserId="28422" LastEditDate="2023-02-03T15:31:40.607" LastActivityDate="2023-02-03T15:31:40.607" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24841" PostTypeId="1" AcceptedAnswerId="24842" CreationDate="2023-02-05T14:58:06.133" Score="1" ViewCount="376" Body="&lt;p&gt;According to Buys Ballot's law:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;When you stand with your back to the wind in the Northern Hemisphere,&#xA;low pressure is always to your left. (In the Southern Hemisphere,&#xA;low-pressure systems will be on your right.)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It implies that &lt;em&gt;geostrophic wind&lt;/em&gt; blows in parallel to low and high pressure zone, for example I'm in the Northern Hemisphere, wind blows to my back, low pressure is always to my left and high pressure is always to my right. But I thought that wind always blows from the high pressure zone to the low pressure zone. How this contradiction may be explained?&lt;/p&gt;&#xA;" OwnerUserId="28215" LastActivityDate="2023-02-05T21:19:28.547" Title="Geostrophic wind vs surface wind" Tags="|meteorology|wind|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24842" PostTypeId="2" ParentId="24841" CreationDate="2023-02-05T21:19:28.547" Score="3" Body="&lt;p&gt;Coriolis force plays an important role. A geostrophic wind forms under special conditions when the coriolis force and the pressure gradient are the only forces acting on a parcel of air, and they balance each other out. If a wind blows fast enough in a region with almost straight parallel isobars, the coriolis force can be equal in magnitude and point in the opposite direction of the pressure gradient, so in that case the wind will not change direction and so it will keep the low and high on its sides (depending on the hemisphere). Usually in reality we get near-geostrophic winds because other forces are never really absent, just order of magnitude lower than coriolis force and pressure gradient (for example very little turbulent drag)&lt;/p&gt;&#xA;" OwnerUserId="28351" LastActivityDate="2023-02-05T21:19:28.547" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24843" PostTypeId="1" CreationDate="2023-02-05T22:57:48.510" Score="2" ViewCount="178" Body="&lt;p&gt;This stone was found at the beach on the Danish side of Øresund (Amager strand in Copenhagen). I believe it is flint, though I am not sure. There is a pattern of rings on one of its sides (see photos). What could be the source of that?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/lGQ84.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/lGQ84.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kUcYR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kUcYR.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="28435" LastEditorDisplayName="user28185" LastEditDate="2023-02-14T03:28:22.073" LastActivityDate="2023-02-14T03:28:22.073" Title="Identify source of rings pattern in flint" Tags="|rocks|identify-this-object|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="24844" PostTypeId="1" CreationDate="2023-02-06T10:53:58.823" Score="2" ViewCount="3165" Body="&lt;p&gt;So, I did some measurements in ICP-OES and the results were given to me in elemets. However, I need to convert the results to oxides. After some googling I found out that I need to use simple conversion factors that are based on the molecular weight and amount of cations in the molecules. The problem is, I found some data on a book (Winter's book on Petrology) and apparently he did calculations that I could not understand.&#xA;For example : He converted 59.3% SiO2 to 21% of Si.&#xA;If I use the conversion factor of 0.4674, I would get that 59.3% of SiO2 is equal to 27.71 of Si.&lt;/p&gt;&#xA;&lt;p&gt;What am I missing here?&lt;/p&gt;&#xA;" OwnerUserId="28436" LastActivityDate="2023-02-13T02:30:46.067" Title="How do I convert an element measurement to oxides?" Tags="|geology|geochemistry|biogeochemistry|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24845" PostTypeId="1" CreationDate="2023-02-06T11:49:46.237" Score="1" ViewCount="60" Body="&lt;p&gt;I have trouble understanding the Rossby waves in the atmosphere.&#xA;Sometimes they are said to be caused by the jets moving from west to east. But the phase velocity of the waves is in the west direction and the group velocity depends on the number of waves. So how do the waves move now?&lt;/p&gt;&#xA;&lt;p&gt;Also, it is not clear to me if the Rossby waves are deflected by high/low pressure systems, or do they generate them? And if they generate them, how do they do that? They only move air vertically, so how can high and low pressure areas be created? Does this have anything to do with barotropic and baroclinic conditions?&lt;/p&gt;&#xA;" OwnerUserId="28437" LastEditorUserId="28437" LastEditDate="2023-02-06T12:21:07.867" LastActivityDate="2023-02-06T12:21:07.867" Title="Rossby waves in the atmosphere" Tags="|meteorology|climate|fluid-dynamics|coriolis|vorticity|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24846" PostTypeId="1" AcceptedAnswerId="24854" CreationDate="2023-02-06T14:38:42.390" Score="3" ViewCount="1090" Body="&lt;p&gt;There is a widely circulated &lt;a href=&quot;https://twitter.com/hogrbe/status/1621479563720118273&quot; rel=&quot;nofollow noreferrer&quot;&gt;tweet by Frank Hoogerbeets&lt;/a&gt; where it seems he has predicted &lt;a href=&quot;https://edition.cnn.com/2023/02/05/europe/earthquake-hits-turkey-intl-hnk/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Turkey's earthquake&lt;/a&gt; a few days before. The tweet says:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Sooner or later there will be a ~M 7.5 #earthquake in this region (South-Central Turkey, Jordan, Syria, Lebanon). #deprem&#xA;&lt;a href=&quot;https://i.stack.imgur.com/2WrGU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2WrGU.jpg&quot; alt=&quot;the map&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I have searched a bit about the origin of this so-called prediction. They have a &lt;a href=&quot;https://www.youtube.com/@ssgeos&quot; rel=&quot;nofollow noreferrer&quot;&gt;youtube channel&lt;/a&gt; since a few month ago, which is regularly updated by &lt;a href=&quot;https://www.youtube.com/watch?v=TZL-pJh3QaU&quot; rel=&quot;nofollow noreferrer&quot;&gt;videos like this&lt;/a&gt; in which he analyzes the planetary alignments and claims that it has something to do with Earth's seismic activities. I haven't seen such claim anywhere before and wanted to check whether it has been scientifically approved, or does it have any merit whatsoever?&lt;/p&gt;&#xA;" OwnerUserId="28438" LastEditorUserId="2470" LastEditDate="2023-02-08T01:48:28.297" LastActivityDate="2023-02-08T02:11:50.680" Title="Do planetary alignments affect Earth's seismic activity?" Tags="|earthquakes|seismology|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24847" PostTypeId="2" ParentId="24844" CreationDate="2023-02-06T16:58:13.033" Score="4" Body="&lt;p&gt;If you are talking about Table 2 of Chapter 8 in &lt;em&gt;Principles of Igneous and Metamorphic Petrology&lt;/em&gt; (Winter, 2013), p. 146 in the second edition, then you are misreading the column headers. 59.3 is in 'Wt. % Oxide', i.e., it is a mass fraction, while 21.2 is in 'Atomic %' (atomic percent, no mass involved). The way this is calculated is explained on the same page for Table 1, which has more columns showing the details of the calculation.&lt;/p&gt;&#xA;&lt;p&gt;For what you want to do, going from wt% element to wt% oxide, all you have to do is multiply by a conversion factor, which is 2.1393 for silicon (the 0.4674 factor you mentioned is to go the other way around, from oxide to element). Be careful with iron, there are two different factors depending on the state of oxidation (&lt;span class=&quot;math-container&quot;&gt;$\ce{FeO}$&lt;/span&gt; vs. &lt;span class=&quot;math-container&quot;&gt;$\ce{Fe2O3}$&lt;/span&gt;), but I'm not sure how you can discriminate between the two with your elemental analysis...&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2023-02-06T16:58:13.033" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24848" PostTypeId="1" CreationDate="2023-02-07T00:24:39.857" Score="3" ViewCount="79" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QIjI2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QIjI2.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The linearized f-plane shallow water equations are:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;&lt;span class=&quot;math-container&quot;&gt;$du'/dt - fv' = -g(d eta'/dx)$&lt;/span&gt;&#xA;dv'/dt + fu' = -g(d eta'/dy)&#xA;(d eta'/dt) + H((du'/dx)+(dv'/dy)) = 0&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;where g is gravitational acceleration, f is the Coriolis parameter, eta is sea surface height, H is depth, u and v are the horizontal components of velocity, and primes denote linearized variables. I am very lost on how to even begin the problem in the image. Do I need to plug in the equation eta = eta(k,l)*e^i(kx+ly) dkdl to the linearized equations and then calculate the geostrophic adjustment?&lt;/p&gt;&#xA;&lt;p&gt;My understanding of Fourier coefficients is very loose and both my teacher's notes and my textbook are lacking in the math necessary to solve these equations.&lt;/p&gt;&#xA;" OwnerUserId="28440" LastEditorUserId="2470" LastEditDate="2023-09-27T07:22:02.813" LastActivityDate="2023-09-27T07:22:02.813" Title="Geostrophic adjustment with shallow water equations" Tags="|oceanography|waves|fluid-dynamics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24849" PostTypeId="2" ParentId="18105" CreationDate="2023-02-07T02:44:11.937" Score="3" Body="&lt;p&gt;In addition to chemosynthesis by living organisms, carbon dioxide can be reduced to methane and more complex hydrocarbons by &lt;a href=&quot;https://en.wikipedia.org/wiki/Serpentinization&quot; rel=&quot;nofollow noreferrer&quot;&gt;serpentization&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Serpentization is a high-temperature, high-pressure reaction between mafic minerals (principally olivines and pyroxenes) and water to form a less mafic mineral, from the serpentine group (including serpentine itself and talc, among others). The reaction displaces iron and magnesium oxides. The magnesium oxide is purely basic and emerges combined with water to form magnesium hydroxide (brucite) or perhaps with carbon dioxide to give magnesium carbonate (magnesite) or other carbonate minerals. The iron oxide is a reducing agent, tending to convert from the &lt;span class=&quot;math-container&quot;&gt;$\ce{FeO}$&lt;/span&gt; component of the mafic minerals to &lt;span class=&quot;math-container&quot;&gt;$\ce{Fe3O4}$&lt;/span&gt; (magnetite) with displacement of hydrogen from water. As described in the Wikipedia article, carbon dioxide may also be reduced, especially in the presence of the water, to produce hydrocarbons:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Laboratory experiments have confirmed that at a temperature of 300 °C (572 °F) and pressure of 500 bars, olivine serpentinizes with release of hydrogen gas. In addition, methane and complex hydrocarbons are formed through reduction of carbon dioxide. The process may be catalyzed by magnetite formed during serpentinization.[&lt;a href=&quot;https://pubs.geoscienceworld.org/gsa/geology/article/24/4/351/206512/Reduction-of-CO2-during-serpentinization-of&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;] One reaction pathway is:[&lt;a href=&quot;https://doi.org/10.1111/j.1472-4669.2010.00249.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;]&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{18\overset{forsterite}{Mg2SiO4} + 6\overset{fayalite}{Fe2SiO4} + 26 H2O + CO2 -&amp;gt; 12\overset{serpentine}{Mg3Si2O5(OH)4} + 4\overset{magnetite}{Fe3O4} + \overset{methane}{CH4}}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Serpentization is widely studied by planetary scientists because when they search for signatures of life, they reckon with serpentization as an alternate source of the organic matter they observe -- and as a source for the raw materials organisms might use.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Cited References&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Berndt, Michael E.; Allen, Douglas E.; Seyfried, William E. (1 April 1996). &amp;quot;Reduction of CO2 during serpentinization of olivine at 300 °C and 500 bar&amp;quot;. _Geology &lt;strong&gt;24&lt;/strong&gt; (4): 351–354. Bibcode:1996Geo....24..351B. DOI: 10.1130/0091-7613(1996)024&amp;lt;0351:ROCDSO&amp;gt;2.3.CO;2.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Russell, M. J.; Hall, A. J.; Martin, W. (2010). &amp;quot;Serpentinization as a source of energy at the origin of life&amp;quot;. _Geobiology &lt;strong&gt;8&lt;/strong&gt; (5): 355–371. &lt;a href=&quot;https://doi.org/10.1111/j.1472-4669.2010.00249.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1111/j.1472-4669.2010.00249.x&lt;/a&gt;. PMID 20572872. S2CID 41118603.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2023-02-07T13:38:21.127" LastActivityDate="2023-02-07T13:38:21.127" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24851" PostTypeId="1" CreationDate="2023-02-07T17:10:33.297" Score="1" ViewCount="29" Body="&lt;p&gt;Norway would fit in a bounding box of 500x1600x3 km, where 500 km is east-west, 1600 is north-south, and 3 km is up-down. What do you call these dimensions?&lt;/p&gt;&#xA;&lt;p&gt;When speaking about furniture, you use width, depth, and height, but depth is confusing, because in this context it would be the opposite of height.&lt;/p&gt;&#xA;" OwnerUserId="601" LastEditorUserId="601" LastEditDate="2023-02-07T17:30:27.940" LastActivityDate="2023-02-07T17:30:27.940" Title="Naming dimensions of a chunk of earth" Tags="|geography|terminology|" AnswerCount="0" CommentCount="2" ClosedDate="2023-02-08T06:10:39.580" ContentLicense="CC BY-SA 4.0" />
  <row Id="24852" PostTypeId="1" CreationDate="2023-02-07T17:39:10.963" Score="5" ViewCount="216" Body="&lt;p&gt;Felsic rocks contain a lot of sodium, potassium and calcium (and a great deal of aluminum), while mafic rocks consist of a lot of magnesium with iron....&lt;/p&gt;&#xA;&lt;p&gt;Why is this?&lt;/p&gt;&#xA;&lt;p&gt;Why is magnesium (z=12) in the denser rock(s) with iron (z=26), while aluminum (13) and calcium (20) get stuck nearer the surface with lightweight sodium (11)?&lt;/p&gt;&#xA;&lt;p&gt;I haven't found a reason for this...&lt;/p&gt;&#xA;&lt;p&gt;P.S.:  What about potassium and sodium?  Are they also unable to easily fit into iron rocks as well?  After all, they also end up, generally, closer to the surface....&lt;/p&gt;&#xA;" OwnerUserId="20985" LastEditorUserId="20985" LastEditDate="2023-02-27T11:54:09.073" LastActivityDate="2024-01-17T01:38:17.730" Title="Why does calcium occur together with felsic rocks and magnesium with mafic rocks if calcium is denser than magnesium?" Tags="|geology|geophysics|geochemistry|rocks|bedrock|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24853" PostTypeId="1" CreationDate="2023-02-07T22:35:04.870" Score="1" ViewCount="23" Body="&lt;p&gt;You surely know the &lt;a href=&quot;https://en.wikipedia.org/wiki/Land_and_water_hemispheres&quot; rel=&quot;nofollow noreferrer&quot;&gt;&amp;quot;water hemisphere&amp;quot;&lt;/a&gt; of Earth. Have other hemispheres been computed? (For example, Wiki notes &amp;quot;population hemisphere&amp;quot; coincides more or less with the &amp;quot;land hemisphere&amp;quot;, which is not surprising.) &amp;quot;Temperature hemisphere&amp;quot; might be interesting, but perhaps too variable.&lt;/p&gt;&#xA;" OwnerUserId="28449" LastActivityDate="2023-02-07T22:35:04.870" Title="Hemispheres with some property" Tags="|mapping|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24854" PostTypeId="2" ParentId="24846" CreationDate="2023-02-08T02:11:50.680" Score="7" Body="&lt;p&gt;It's easy to make prediction of earthquakes in Turkey/Türkiye, it's in one of the most &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_earthquakes_in_Turkey&quot; rel=&quot;noreferrer&quot;&gt;active seismic zones&lt;/a&gt; on the planet.&lt;/p&gt;&#xA;&lt;p&gt;The February 2023 earthquake had a magnitude of 7.8, with aftershocks of magnitude 7.5.&lt;/p&gt;&#xA;&lt;p&gt;In 2020 there was a magnitude 7 quake, 6.9 in 2014, 7.2 in 2011, 7.2 and 7.6 in 1999, 7.5 in 1976, 7 in 1964, two 7.1 quakes in 1957, 7.2 in 1953, 7.5 in 1944 and another 7.8 quake in 1939.&lt;/p&gt;&#xA;&lt;p&gt;Turkey/Türkiye is no stranger to earthquakes. They are a continual, if not unwelcome, companion.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.usgs.gov/faqs/can-position-moon-or-planets-affect-seismicity-are-there-more-earthquakes-morningin-eveningat&quot; rel=&quot;noreferrer&quot;&gt;alignment of planets&lt;/a&gt; has effective &lt;a href=&quot;https://earthsky.org/space/planetary-alignment-increase-in-volcanoes-july-2020/&quot; rel=&quot;noreferrer&quot;&gt;nothing to do with earthquakes&lt;/a&gt;. Any effect is very small.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The moon, sun, and other planets have an influence on the earth in the form of perturbations (small changes) to the gravitational field. The relative amount of influence is proportional to the objects mass, and inversely proportional to the third power of its distance from the earth.&lt;/p&gt;&#xA;&lt;p&gt;There have been several planet-alignment scares. “The Jupiter Effect” (1974), by John Gribbin and Stephen Plagemann, predicted that a line-up on March 10, 1982, would cause catastrophes including a great earthquake on the San Andreas Fault.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;That did not happen.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-02-08T02:11:50.680" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24855" PostTypeId="1" CreationDate="2023-02-08T10:18:12.947" Score="1" ViewCount="97" Body="&lt;p&gt;I have a dataset from ERA LAND with a Volumetric Soil Water (m3 m&lt;sup&gt;-3&lt;/sup&gt;), How I could convert to a Gravimetric Moisture content (kg kg&lt;sup&gt;-1&lt;/sup&gt;)?&lt;/p&gt;&#xA;" OwnerUserId="28451" LastEditorUserId="2470" LastEditDate="2023-09-27T07:14:19.493" LastActivityDate="2023-09-27T07:14:19.493" Title="Volumetric Soil Water to Gravimetric Moisture" Tags="|soil-moisture|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24856" PostTypeId="2" ParentId="24855" CreationDate="2023-02-08T11:44:32.200" Score="1" Body="&lt;p&gt;Use bulk densities of water and the ground in question.&lt;/p&gt;&#xA;&lt;p&gt;Density, ρ, is mass divided by volume.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\ \ \rho \ = \ \frac{m}{V}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Rearrange the equation to get mass, density times volume.&lt;/p&gt;&#xA;&lt;p&gt;Depending on how fancy you want get, by making allowances for temperature and impurities, the density of water of 1 g/cm&lt;sup&gt;3&lt;/sup&gt; (1 t/m&lt;sup&gt;3&lt;/sup&gt; or 1000 kg/m&lt;sup&gt;3&lt;/sup&gt;).&lt;/p&gt;&#xA;&lt;p&gt;You next need to know the basic geology of the region in question and use appropriate values of &lt;a href=&quot;https://www.structx.com/Soil_Properties_002.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;density&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-02-08T11:44:32.200" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24857" PostTypeId="1" CreationDate="2023-02-08T13:31:20.683" Score="3" ViewCount="65" Body="&lt;p&gt;I know that, hurricanes/cyclones move from east to west because they are caught up in the trade winds, which blow from east to west near the equator. Once a hurricane/cyclone moves north of about 30 latitude, they frequently curve, and often do move from west to east. Today I opened windy.com and found that &lt;a href=&quot;https://www.windy.com/-Hurricane-tracker/hurricanes/gabrielle?-32.085,155.186,3&quot; rel=&quot;nofollow noreferrer&quot;&gt;one hurricane&lt;/a&gt; close to equator moves from west to east my question is next: what affects this movement from west to east?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ANgg4.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ANgg4.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28215" LastEditorUserId="2470" LastEditDate="2023-02-09T00:20:22.077" LastActivityDate="2023-02-09T00:20:22.077" Title="Hurricane/Cyclone movement direction" Tags="|meteorology|tropical-cyclone|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24859" PostTypeId="2" ParentId="12106" CreationDate="2023-02-09T05:19:40.110" Score="1" Body="&lt;p&gt;It varies depending on the elasticity of the building.&lt;/p&gt;&#xA;&lt;p&gt;If the building is earthquake proofed, it will tend to dampen the effect of the quake, so that the top can shake less than the base.&lt;/p&gt;&#xA;&lt;p&gt;If the building is stiff masonry, it will crack when the difference between the base and the upper levels exceed 2-3 inches for every floor, and when it's higher than that, there are good chances that the building will collapse.&lt;/p&gt;&#xA;&lt;p&gt;The violence on different levels depends on the resonance of the building, the swing effect. If the resonance at the top compensates the periodicity of the quake, it will be less violent at the top.&lt;/p&gt;&#xA;&lt;p&gt;If the resonance amplifies the quake, the top will swing additively, so that the top will have a bigger movement than the base.&lt;/p&gt;&#xA;&lt;p&gt;That's another reason different buildings have different chances of collapsing based on their resonance.&lt;/p&gt;&#xA;&lt;p&gt;It's possible that one end shakes a greater distance while another end shakes faster with less amplitude / less range.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastActivityDate="2023-02-09T05:19:40.110" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24860" PostTypeId="1" CreationDate="2023-02-09T16:06:04.983" Score="2" ViewCount="33" Body="&lt;p&gt;I have read many articles about drought forecasting, but I always come across the concept of 'lead time' for SPI forecasting. Please can someone who knows the subject briefly explain the concept of 'lead time' to me? As far as I understand, it is a time scale, but how is it different from a timescale?&lt;/p&gt;&#xA;" OwnerUserId="28457" LastEditorUserId="28457" LastEditDate="2023-02-09T16:07:50.870" LastActivityDate="2023-02-09T16:07:50.870" Title="Drought Prediction" Tags="|weather-forecasting|precipitation|drought|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24861" PostTypeId="1" AcceptedAnswerId="24872" CreationDate="2023-02-09T17:55:44.563" Score="4" ViewCount="67" Body="&lt;p&gt;In the footage of Arctic sea ice in the spring or summer you can see gaps of water, lines of water between ice sheets, or kind of lakes of water mixed with icebergs. Even as far north as the North Pole there are still water gaps between ice.&lt;/p&gt;&#xA;&lt;p&gt;Is it the same in winter, or does Arctic in winter form a single continuous sheet of ice? Does it stretch all the way between Russia and Canada? So in theory you could drive a vehicle over it?&lt;/p&gt;&#xA;" OwnerUserId="28459" LastEditorUserId="28459" LastEditDate="2023-02-09T17:56:48.790" LastActivityDate="2023-02-11T05:31:59.407" Title="Does Arctic sea ice form a continuous flat sheet in winter between Russia and Canada, or are there gaps of water?" Tags="|oceanography|ice|arctic|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24862" PostTypeId="1" CreationDate="2023-02-09T18:14:32.897" Score="1" ViewCount="23" Body="&lt;p&gt;Some big wildfires are hitting some places in Chile. I have read that aqueous bodies can be affected during/after major wildfires. Is it possible to determine if it is safe to drink spring water (flowing from rocks/roots of a tree/underground sources) just by observing the water and its surroundings, without examining the water to determine its composition ? (some signal where to put attention to the naked eye)&lt;/p&gt;&#xA;&lt;p&gt;Compared to (for example, in the same region) water coming from other type of aqueous bodies (this, in regions not suffering with wildfires, but, adjacent to, and presenting some variation in weather due to smoke).&lt;/p&gt;&#xA;" OwnerUserId="28458" LastActivityDate="2023-02-09T18:14:32.897" Title="Water comparison of different aqueous bodies in regions not affected by wildfire but adjacent to affected ones" Tags="|water|wildfire|underground-water|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24863" PostTypeId="2" ParentId="24852" CreationDate="2023-02-09T18:27:36.240" Score="5" Body="&lt;p&gt;First off, calcium is more generally associated with mafic rocks than with felsic rocks. &lt;a href=&quot;https://en.wikipedia.org/wiki/Mafic&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mafic&lt;/a&gt; rocks often include calcium-rich plagioclase feldspars.&lt;/p&gt;&#xA;&lt;p&gt;Calcium is actually less dense than magnesium when they are elements, and it is so when they are incorporated as ions in rocks. As described &lt;a href=&quot;https://earthscience.stackexchange.com/a/20798/20607&quot;&gt;here&lt;/a&gt;, magnesium ions are lighter than calcium ions but also smaller and incorporated into more compact lattices. Therefore magnesium oxide and silicates have nearly the same density as their calcium counterparts. Moreover, magnesium in mafic rocks — unlike calcium — occurs intermingled in solid solution with iron (and some other transition metals), which increases the density of the magnesium-bearing rock. Magnesium and iron ions are similar in size as well as charge and thus can intermingle freely, whereas calcium ions are too large to fit into the same lattice sites. Thereby magnesium-rich mafic rocks, or more accurately magnesium-iron-rich mafic rocks, are denser than mafic rocks that contain more calcium. Over time the calcium-rich rock has tended to float towards the top of the predominantly magnesium-iron rich, mafic/ultramafic rock structure of Earth's crust and mantle.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2024-01-17T01:38:17.730" LastActivityDate="2024-01-17T01:38:17.730" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24867" PostTypeId="1" CreationDate="2023-02-10T09:00:00.730" Score="1" ViewCount="28" Body="&lt;p&gt;How does Madden-Julian Oscillation (MJO) affects Tropical cyclones, onset of monsoon and the ENSO Cycle?&lt;/p&gt;&#xA;&lt;p&gt;I cant seem to find any &amp;quot;general explanation&amp;quot; (concept wise) for how MJO affects the TC, monsoon and ENSO cycle&lt;/p&gt;&#xA;" OwnerUserId="28416" LastActivityDate="2023-02-10T09:00:00.730" Title="How does Madden-Julian Oscillation (MJO) affects Tropical cyclones, onset of monsoon and the ENSO Cycle?" Tags="|meteorology|atmosphere|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24868" PostTypeId="1" CreationDate="2023-02-10T16:46:21.053" Score="1" ViewCount="28" Body="&lt;p&gt;We've been hearing a lot these past few days about planes alignments and how it would affect seismology. How scientifically true is that?&lt;/p&gt;&#xA;" OwnerUserId="28465" LastActivityDate="2023-02-10T16:46:21.053" Title="Can the planetary alignment actually affect earthquakes?" Tags="|earthquakes|seismology|planetary-science|earth-system|planets|" AnswerCount="0" CommentCount="0" ClosedDate="2023-02-11T03:20:11.063" ContentLicense="CC BY-SA 4.0" />
  <row Id="24869" PostTypeId="1" AcceptedAnswerId="24871" CreationDate="2023-02-10T21:50:35.333" Score="12" ViewCount="687" Body="&lt;p&gt;I've been trying to find sources detailing the natural geographic features most suitable for shipping harbors along a coast—primarily for international trade. So far, I've read vague reference to bathymetry and natural harbors. What other geographic conditions should affect the viability of shipping (historically) along a country coastline?&lt;/p&gt;&#xA;" OwnerUserId="28466" LastEditorUserId="6467" LastEditDate="2023-02-14T18:06:09.577" LastActivityDate="2023-02-16T00:26:06.603" Title="Most amenable coastal geographic conditions for harbors?" Tags="|oceanography|geography|bathymetry|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24870" PostTypeId="1" CreationDate="2023-02-10T23:07:20.060" Score="2" ViewCount="27" Body="&lt;p&gt;A thought was you could create large, reflective white snow area, and offset the ocean rise.  Curious to know if this has potential effect on climate crisis.  As a bystander I know that if you bury an army they aren't going to be fighting anymore but I am most curious about the effect on Earth if such a project could be taken on.  Did read once about super volcanos in Russian land, and could this in-fact protect against those going off too?&lt;/p&gt;&#xA;&lt;p&gt;I've seen all kinds of dredging-ops and its effectively a vacuum ship of sort.  That's the kind of operation I'm thinking of?&lt;/p&gt;&#xA;&lt;p&gt;Edit:&#xA;What focuses this effort any more?  I am choosing the area of the earth, choosing the operation type, and taken from where...  Time frame I suppose is whatever.. Obviously a huge operation and it could take hundreds of years but so does climate change... I dunno I feel like you people are bullying me, As Usual.  Every, single time.&lt;/p&gt;&#xA;" OwnerUserId="28467" LastEditorUserId="28467" LastEditDate="2023-02-11T01:16:44.010" LastActivityDate="2023-02-11T01:16:44.010" Title="If you dredge and move ocean floor deposit onto Russia and create mountains, can we influence sea level and temperature?" Tags="|geoengineering|" AnswerCount="0" CommentCount="7" ClosedDate="2023-02-11T00:10:21.750" ContentLicense="CC BY-SA 4.0" />
  <row Id="24871" PostTypeId="2" ParentId="24869" CreationDate="2023-02-11T03:44:50.883" Score="12" Body="&lt;p&gt;Here are some considerations:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;It needs to be deep enough that you can get close to shore with a ship that extends several meters below sea level.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;It needs to be protected from large waves, so a spit of land that goes around the harbor is useful.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;It shouldn't be in a place where tides are large and ships will be moving up and down over the course of a day by too much to make loading and unloading difficult.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;It shouldn't be in a place where winds are frequently too strong to make operations difficult.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="5259" LastEditorUserId="5259" LastEditDate="2023-02-16T00:26:06.603" LastActivityDate="2023-02-16T00:26:06.603" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24872" PostTypeId="2" ParentId="24861" CreationDate="2023-02-11T03:54:57.347" Score="4" Body="&lt;p&gt;It is interesting to read reports from explorers Nansen, Amadeo, Cook, Peary, and others who all tried (and some of whom -- possibly -- succeeded) to reach the North Pole by skis and sleds in the years around 1900. They all complained bitterly about the fact that the ice cap is not continuous, even though they all left their wintering bases at the end of winter -- during the time when there was the most ice, the sun was barely out, and it was incredibly cold.&lt;/p&gt;&#xA;&lt;p&gt;Part of the problem is that the ice, even during winter months, keeps moving with the currents, the tides, and the wind, and not as one rigid body but as separate &amp;quot;plates&amp;quot;. This creates gaps between the individual floes that, in winter, freeze over eventually but not quickly enough to completely cover the entire area.&lt;/p&gt;&#xA;&lt;p&gt;All of the explorers mentioned above did not make it to the pole, or maybe just so did, with skis and dog-drawn sleds. It seems hard to believe that they could have made it with motor vehicles (even ones from our current times) and it certainly seems inconceivable that one could make it today given how much less ice there is a hundred years on from their reports. Yet, &lt;a href=&quot;https://en.wikipedia.org/wiki/North_Pole#MLAE_2009_Expedition&quot; rel=&quot;nofollow noreferrer&quot;&gt;it appears that some Russians managed to do exactly this&lt;/a&gt;, but I'm not familiar with any of the details.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastEditorUserId="2470" LastEditDate="2023-02-11T05:31:59.407" LastActivityDate="2023-02-11T05:31:59.407" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24873" PostTypeId="2" ParentId="24869" CreationDate="2023-02-11T05:50:12.593" Score="12" Body="&lt;p&gt;The answer by @wolfgang_bangerth concentrates on the maritime conditions. What also is required are conditions on land that would make such locations useful as ports for international trade.&lt;/p&gt;&#xA;&lt;p&gt;The land adjacent to such maritime locations needs to be reasonably flat and cover a large area so that holding yards can be established for goods arriving and leaving via a port and to facilitate land based transport networks, such as rail and road, in moving goods to and from ports. Steep coastlines, as one finds with fjords, are sub optimal for use as ports.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-02-11T05:50:12.593" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24875" PostTypeId="2" ParentId="24054" CreationDate="2023-02-12T19:09:34.297" Score="1" Body="&lt;p&gt;I think the analogy would be large volcanic eruptions - 1991 Mount Pinatubo for instance. Volcanic eruptions which locally &lt;a href=&quot;https://www.science.org/content/article/thanks-volcanoes-earth-cooler-expected-due-recent-eruptions&quot; rel=&quot;nofollow noreferrer&quot;&gt;spew large amounts of light-scattering aerosols into the stratosphere&lt;/a&gt; don't remain there long due to the earth's weather and eventually contribute to global effects.&lt;/p&gt;&#xA;&lt;p&gt;Dipping into SciFi speculation, if you had a constant source of injection into the stratosphere upwind of a specific location, I would think that location's climate would be modified, but the effect would most certainly continue on downwind - perhaps eventually globally?&lt;/p&gt;&#xA;" OwnerUserId="27988" LastActivityDate="2023-02-12T19:09:34.297" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24876" PostTypeId="1" AcceptedAnswerId="24878" CreationDate="2023-02-12T20:55:17.280" Score="1" ViewCount="116" Body="&lt;p&gt;During an attempt to extract iron from iron ore (magnetite), we were mostly unsuccessful. Some small grains of metallic-looking material was however present in the mixture following our attempt (see photo). This metal(?) is not magnetic. What could it be?&lt;/p&gt;&#xA;&lt;p&gt;We used ore sampled from an abandoned quarry with the following specifications:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;Main type of deposit: Iron oxide&#xA;Host rock: calc -silicate / skarn&#xA;Wall rock: Felsic volcanic rock&#xA;Age of deposit: Palaeproterozoic&#xA;Main metals: Fe, Cu, Zn, Pb, Ag&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;We collected the rocks using strong magnets (indicating magnetite). We then smashed them into powder and filtered out the magnetite using magnets. We then mixed it 1:1 by volume with charcoal powder and put them in an improvised crucible, which we heated using a propane torch. Most of the magnetite seemed unaffected (too low temperature I guess, since we did not have a proper, insulated furnace), although we found many silvery-gray shiny grains in the mixture afterwards (as shown in the photo). We could not see these grains before the heating. These grains are not magnetic.&lt;/p&gt;&#xA;&lt;p&gt;What do you think that this is?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RHh1h.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RHh1h.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15244" LastEditorUserId="15244" LastEditDate="2023-02-12T21:25:08.473" LastActivityDate="2023-02-13T02:10:55.243" Title="Non-magnetic metal extracted from magnetite ore" Tags="|ore|iron|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24877" PostTypeId="1" CreationDate="2023-02-12T21:18:01.183" Score="1" ViewCount="180" Body="&lt;p&gt;I'm trying to make a weather simulator using the article &lt;em&gt;Interactive Meso-scale Simulation of Skyscapes&lt;/em&gt;. It gives the formula for calculating the mean static energy:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$MSE_i = C_p \cdot T_i + g \cdot \Theta_i + L_v \cdot Q_i$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;But I don't understand how to calculate specific humidity, the article says that it can be calculated using absolute humidity (&lt;span class=&quot;math-container&quot;&gt;$H_i$&lt;/span&gt;) and height above the ground (&lt;span class=&quot;math-container&quot;&gt;$\Theta_i$&lt;/span&gt;) (quote: &lt;span class=&quot;math-container&quot;&gt;$Q_i$&lt;/span&gt; is the specific humidity of the air layer (and can be derived from &lt;span class=&quot;math-container&quot;&gt;$H_i$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\Theta_i$&lt;/span&gt;)). Is there any specific formula for calculating specific humidity or am I missing something?&lt;/p&gt;&#xA;&lt;p&gt;Update 1.&lt;/p&gt;&#xA;&lt;p&gt;So I have implemented a function to calculate specific humidity in python. Here &lt;strong&gt;AH&lt;/strong&gt; is the absolute humidity in &lt;span class=&quot;math-container&quot;&gt;$g/m^3$&lt;/span&gt;, &lt;strong&gt;p&lt;/strong&gt; is the pressure in pascals at the calculation point and &lt;strong&gt;t&lt;/strong&gt; is temperature in Celsius.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;def get_specific_humidity(AH, t, p):&#xA;    e = (AH / 1000) * 461.5 * (t + 273.15)&#xA;    r =  (0.622 * e) / (p - e)&#xA;    return r / (1 + r)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;First I calculated the vapor pressure &lt;strong&gt;e&lt;/strong&gt; using the formula:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{m}{V} = \frac{e}{R_vT}$$&lt;/span&gt;&#xA;The calculation assumes that the dry air is evenly mixed with water. Also &lt;span class=&quot;math-container&quot;&gt;$R_v=461.5$&lt;/span&gt; is specific gas constant for water vapor. Next, I calculated the mixing ratio using this equation:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$r=\frac{0.622e}{p-e}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;And finally using the mixing ratio it is possible to calculate the specific humidity:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$q=\frac{r}{1+r}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Did I do everything right?&lt;/p&gt;&#xA;" OwnerUserId="28475" LastEditorUserId="28475" LastEditDate="2023-02-23T13:37:34.833" LastActivityDate="2024-03-19T15:04:25.543" Title="How to get specific humidity through absolute humidity and height above ground" Tags="|humidity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24878" PostTypeId="2" ParentId="24876" CreationDate="2023-02-13T02:10:55.243" Score="3" Body="&lt;p&gt;&lt;strong&gt;First, let me start by saying that what you're doing is dangerous. You have no idea what's in the ore, whether it is volatile, if any vapour is toxic, etc. This is especially since the rocks contain lead, which can evaporate at high enough temperatures. Similar rocks often contain arsenic, and potentially mercury.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Stop doing this.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Geometallurgy operations have many safety protocols which were written in blood.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now, to answer your question, based on your description, this is most likely either zinc, or lead, or a zinc–lead alloy. As Fred said in the comments, a density check would probably be the easiest way to do it. Lead is very dense, and zinc is also denser than both iron and copper.&lt;/p&gt;&#xA;&lt;p&gt;There are other ways to figure out which metals are in it with all kinds of readily-available acids and other chemicals, but I will not disclose the methods because &lt;em&gt;you should not be doing this.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2023-02-13T02:10:55.243" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24879" PostTypeId="2" ParentId="24852" CreationDate="2023-02-13T02:21:53.633" Score="3" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;if calcium is denser than magnesium?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Because chemical element density has very little to do with whether that element sinks or floats.&lt;/p&gt;&#xA;&lt;p&gt;The &amp;quot;things&amp;quot; that sink or float are &amp;quot;phases&amp;quot; - that is, minerals, or liquids. Each mineral will have a composition made of a variety of different elements, and all these elements together determine the density of the phase.&lt;/p&gt;&#xA;&lt;p&gt;Specifically for calcium, it commonly forms minerals such as plagioclase or clinopyroxene. The density that matters is of the whole thing, not just an element. Clinopyroxene is denser than plagioclase, so when entrained in a free non-turbulent liquid, plagioclase will float relative to clinopyroxene.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2023-02-13T02:21:53.633" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24880" PostTypeId="2" ParentId="24844" CreationDate="2023-02-13T02:30:46.067" Score="1" Body="&lt;p&gt;I never trust conversion factors. Deriving it on your own is super easy:&lt;/p&gt;&#xA;&lt;h3&gt;Conversion from element to oxide&lt;/h3&gt;&#xA;&lt;p&gt;Divide by the molar mass of the element, and multiply by the molar mass of the oxide. For example, molar mass of silicon is 28.085, and of the oxide is 28.085 + 2×15.999 = 60.08. Note that you need this to be on a single cation basis. For oxides like Na&lt;sub&gt;2&lt;/sub&gt;O or Al&lt;sub&gt;2&lt;/sub&gt;O&lt;sub&gt;3&lt;/sub&gt;, you actually need the molar mass of NaO&lt;sub&gt;0.5&lt;/sub&gt; and AlO&lt;sub&gt;1.5&lt;/sub&gt;.&lt;/p&gt;&#xA;&lt;h3&gt;Conversion from oxide to element&lt;/h3&gt;&#xA;&lt;p&gt;Do the opposite. Divide by the molar mass of the oxide, and multiply by the molar mass of the element. For you example of 59.3% SiO&lt;sub&gt;2&lt;/sub&gt;, the answer is 59.3/60.08×28.085=27.72%.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2023-02-13T02:30:46.067" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24881" PostTypeId="2" ParentId="24843" CreationDate="2023-02-13T02:34:35.990" Score="6" Body="&lt;p&gt;What you're looking at is a &lt;a href=&quot;https://en.wikipedia.org/wiki/Conchoidal_fracture&quot; rel=&quot;noreferrer&quot;&gt;conchoidal fracture&lt;/a&gt;. It means you are looking at one half of a larger piece of flint. The strike that broke it occurred on the centre of the radial pattern, and it propagated outwards. Flints are rather hard to break, so I suspect this  means that it was either broken artificially. That is, someone broke it. Not happened naturally. These things do occasionally happen naturally, if it was thrown around during a storm or something.&lt;/p&gt;&#xA;&lt;p&gt;The field of &lt;a href=&quot;https://en.wikipedia.org/wiki/Fractography&quot; rel=&quot;noreferrer&quot;&gt;fractography&lt;/a&gt; deals with the study of fracture patterns.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2023-02-13T02:34:35.990" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24882" PostTypeId="1" CreationDate="2023-02-13T03:58:05.853" Score="1" ViewCount="65" Body="&lt;p&gt;I know that an area has a &lt;em&gt;diurnal tidal&lt;/em&gt; cycle if it experiences one high and one low tide every lunar day. Many areas in the Gulf of Mexico experience these types of tides. I read that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Diurnal tides occur due to a series of factors, among which&#xA;continental interference and the Earth's spin axis are the most&#xA;important to be considered.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;But I don't understand of Earth's tilt affect some ares like the the Gulf of Mexico and don't affect similar places like the Gulf of Oman or the Gulf of Aden&lt;/p&gt;&#xA;" OwnerUserId="28215" LastActivityDate="2023-02-13T03:58:05.853" Title="Reason behind diurnal tides" Tags="|tides|moon|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24884" PostTypeId="1" CreationDate="2023-02-13T09:04:46.050" Score="1" ViewCount="66" Body="&lt;p&gt;We all know that the oxygen levels increase and decrease as well as the temperature, so I believe it's safe to assume atmospheric pressure changes as well... And since granite and basalt are formed with heat and pressure and stuff cooling.. is there any feasible scenario that could make granite behave like clay, if the atmospheric pressure was different as well as the ambient temperature?&#xA;Could drastically different conditions make granite cool so slowly it could be molded?&lt;/p&gt;&#xA;" OwnerUserId="28479" LastActivityDate="2023-02-13T12:17:50.460" Title="Does granite and basalt behave differently in different atmospheric pressures?" Tags="|geology|geochemistry|volcanology|earth-history|geomorphology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24885" PostTypeId="2" ParentId="24884" CreationDate="2023-02-13T10:10:13.273" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Does granite and basalt behave differently in different atmospheric&#xA;pressures?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;h3&gt;Granites&lt;/h3&gt;&#xA;&lt;p&gt;Yes, but not directly. Granites form in the deep Earth, so they don't really care about small differences in oxygen or atmospheric pressure above them. They are going to remain identical whether the pressure on them is 1000 atmospheres, or 1001 atmospheres.&lt;/p&gt;&#xA;&lt;p&gt;However, granites crystallise from molten magma. To make molten magma, you need to take something that's initially solid, and then heat it up. Often, these things that are molten to form the magma that ends up as granite used to be at the surface of the Earth, and then got buried at depth for whatever reasons (usually movement of tectonic plates).&lt;/p&gt;&#xA;&lt;p&gt;These &amp;quot;things&amp;quot; are sedimentary rocks. And if those sedimentary rocks formed when the atmosphere had lots of oxygen (such as the past 600 million years or so), then the magma will be oxidised. If they are earlier, they might be reduced (the opposite of oxidised).&lt;/p&gt;&#xA;&lt;p&gt;Whether a magma is oxidised or not will affect how the granite looks like. Oxidised granites are often a pink because the iron they contain is &amp;quot;rusty&amp;quot;. Non-oxidised granites will be whiter or grey. This tells us a bit about Earth history and past atmospheric conditions.&lt;/p&gt;&#xA;&lt;h3&gt;Basalts&lt;/h3&gt;&#xA;&lt;p&gt;Everything I said for granites is also relevant for basalts (and their deep equivalent, called &amp;quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Gabbro&quot; rel=&quot;nofollow noreferrer&quot;&gt;gabbro&lt;/a&gt;&amp;quot;). For example, oxidised basalts might have a mineral called &amp;quot;magnetite&amp;quot; which is magnetic. But this is at depth. As for basalt lava flows on the surface, the effect of the atmosphere is negligible and don't expect much to happen.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2023-02-13T10:10:13.273" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24886" PostTypeId="2" ParentId="1054" CreationDate="2023-02-13T10:16:07.817" Score="0" Body="&lt;p&gt;I have seen many animals such as large cats and turtles that have went extinct any where from 2 million years ago to 54 million years ago and a wide range on both sides. Many many times there are repeats in a since. All you have to do is watch a couple size comparison videos on you tube to see that evolution repeats it's self occasionally.&lt;/p&gt;&#xA;&lt;p&gt;Furthermore based on the estimates for various population sizes it's quite obvious far less then 1% of animals are ever fossilized. So it's not a stretch to assume any number of species ( intelligent or otherwise) could have easily evolved and died out and never left a recognizable trace.&#xA;And finally... They have found human like species dating back like 4 million years. And 4 million years is a long long time.&lt;/p&gt;&#xA;&lt;p&gt;In conclusion... I sincerely appreciate the question, but the only correct answer is nobody knows. No one has ever found proof there was ancient civilizations so to some mainstream researchers that means there never was. However since no one alive today was around to witness the past then any answer you get is speculation and opinion. It's quite possible humans have evolved repeatedly, even fairly probably if you look at repeats in the fossil record. Unfortunately there is so much political tension over this subject hardly any one will actually read consider and respond accordingly with an answer opinion or idea. It's possible. That's a fact.. is it probable... In my opinion yes. Any one who tries to definitively tell you it never happened isn't worth their weight in salt.&lt;/p&gt;&#xA;&lt;p&gt;The most factual correct answer is we haven't found recognizable proof of multiple cycles...nor has any one ever or will any one ever find proof there were not. You can't prove a negative&lt;/p&gt;&#xA;" OwnerUserId="28479" LastEditorUserId="2470" LastEditDate="2023-02-13T11:53:09.510" LastActivityDate="2023-02-13T11:53:09.510" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24888" PostTypeId="1" CreationDate="2023-02-13T10:25:04.870" Score="1" ViewCount="390" Body="&lt;p&gt;There are several examples of rainbow mountains in various countries. How were they made?&lt;/p&gt;&#xA;" OwnerUserId="28479" LastEditorUserId="2470" LastEditDate="2023-02-13T13:47:58.493" LastActivityDate="2023-02-13T21:37:26.670" Title="How were the rainbow mountains formed?" Tags="|geology|geography|sedimentology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24890" PostTypeId="2" ParentId="24888" CreationDate="2023-02-13T12:26:24.573" Score="2" Body="&lt;p&gt;Following is description of the formation of the &lt;a href=&quot;https://www.forbes.com/sites/trevornace/2016/03/02/rainbow-mountains-china-earths-paint-palette/?sh=470272403e5e&quot; rel=&quot;nofollow noreferrer&quot;&gt;rainbow mountains in China&lt;/a&gt;. Similar processes were involved in the formation of rainbow mountains elsewhere,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Rainbow Mountains are cretaceous sandstones and siltstones that were deposited in China before the Himalayan Mountains were formed. The sand and silt was deposited with iron and trace minerals that provided it with the key ingredient to form the colors we see today.&lt;/p&gt;&#xA;&lt;p&gt;What was once a layered horizontal and flat stratigraphy was disrupted by the Indian Plate colliding into the Eurasian Plate approximately 55 million years ago. Much like when two cars get in a wreck and the bumpers fold and break, a similar process folded what was once flat sandstones into the Rainbow Mountains we see today. This process uplifted mountains and exposed sedimentary rocks that were otherwise hidden well below the surface of the earth. Weathering and erosion removed the overlying layers of continental siliciclastic rocks and exposed underlying formations with different mineralogy and chemistry. This causes the striking variation in colors seen across the Rainbow Mountains.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Essentially, over time silt and sand sediments were deposited. Different sediments had different elements and minerals in them, giving them different colors. The sediments solidified over time. Ground stresses forced some of the sediments to break up, fold and move and over time what was once horizontal is now vertical, or near vertical.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-02-13T12:26:24.573" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24891" PostTypeId="1" CreationDate="2023-02-13T13:32:54.527" Score="4" ViewCount="36" Body="&lt;p&gt;For example, Time for the 2023 Turkey–Syria earthquake is 2023-02-06 01:17:35&#xA;What time does this exactly represent, the start of earthquake's wave or pick of the wave or something else?&lt;/p&gt;&#xA;" OwnerUserId="28480" LastEditorUserId="2470" LastEditDate="2023-02-13T13:39:58.320" LastActivityDate="2024-01-24T21:10:20.183" Title="Which point of an earthquake wave is considered as the earthquake's time?" Tags="|earthquakes|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24893" PostTypeId="1" CreationDate="2023-02-13T21:49:07.567" Score="1" ViewCount="43" Body="&lt;p&gt;I know there is a mainstream answer that thinks the &lt;a href=&quot;https://www.eastwestquest.com/death-valley-national-park/&quot; rel=&quot;nofollow noreferrer&quot;&gt;rainbow sand dunes&lt;/a&gt; they be explained geologically... I just want to know if it's possible to form those colors and those dunes from mining? And if not why do they look exactly like the mine dumps in South America?&lt;/p&gt;&#xA;" OwnerUserId="28479" LastEditorUserId="6298" LastEditDate="2023-02-14T03:14:24.407" LastActivityDate="2023-02-14T10:25:35.087" Title="Is it possible that the rainbow sand dunes in Death Valley, California were formed by some massive mining in the ancient past?" Tags="|geology|geophysics|geochemistry|mineralogy|mining|" AnswerCount="1" CommentCount="2" ClosedDate="2023-02-15T20:55:30.680" ContentLicense="CC BY-SA 4.0" />
  <row Id="24894" PostTypeId="2" ParentId="24893" CreationDate="2023-02-14T10:25:35.087" Score="2" Body="&lt;p&gt;No, not possible.&lt;/p&gt;&#xA;&lt;p&gt;According to a &lt;a href=&quot;https://doi.org/10.3133/ofr9779&quot; rel=&quot;nofollow noreferrer&quot;&gt;report by the United States Geological Survey&lt;/a&gt;, the rocks in and around &amp;quot;Artist's Palette&amp;quot;, which is the place you are describing, are various volcanic rocks: basalts, tuffs, andesites, etc. The colours results from various degrees of weathering. They are stratigraphically consistent just like you would expect from natural rocks, and different to mine dumps. One example from the report:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Unit Ta4A forms the top unit in the &amp;quot;Artist Palette sequence&amp;quot;,&#xA;occurring at Artist Palette and north to Desolation Canyon.&lt;/p&gt;&#xA;&lt;p&gt;...&lt;/p&gt;&#xA;&lt;p&gt;The unit consists mostly of basalt with less abundant andesite and&#xA;minor tuffaceous sedimentary rocks. These rocks are conspicuously&#xA;exposed where Artist Drive follows a narrow canyon through the ridge&#xA;underlain by this unit 1.2 mi (2.0 km) northwest of Artist Palette.&#xA;The basalt is in part solid but agglomerate, cinder agglutinate, and&#xA;conglomerate of basalt clasts are also common. Most is dark-gray but&#xA;color varies to reddish-brown in fresh rocks and greenish-gray in&#xA;altered ones. Most contains sparse plagioclase microphenocrysts.&#xA;Andesite is dark-brownish-gray, aphyric and platy-weathering.&#xA;Interlayered tuffaceous sedimentary rocks are light-gray to pinkish;&#xA;some contain rhyolite fragments.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In other words, nothing special. Just a regular sequence of ancient volcanic rocks.&lt;/p&gt;&#xA;&lt;p&gt;I am not sure which mining dumps you are referring to, but green colours are often associated with copper which is often mined in South America. There is no copper in Death Valley and in the rocks you are asking about. The reason for the green colour is different and unrelated to copper.&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2023-02-14T10:25:35.087" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24895" PostTypeId="1" CreationDate="2023-02-14T14:17:00.927" Score="1" ViewCount="107" Body="&lt;p&gt;In layman's terms, how does the Richter earthquake scale translate to the amplitude of horizontal surface movement at the epicenter?&lt;/p&gt;&#xA;&lt;p&gt;For example, given an earthquake of Richter magnitude 4, what is the horizontal amplitude (in meters) of the surface at the epicenter?&lt;/p&gt;&#xA;&lt;p&gt;And since an earthquake with magnitude 5 is 10 times &amp;quot;stronger&amp;quot; than a 4, would that mean the horizontal amplitude of the magnitude 5 earthquake would be 10 times larger than that of the magnitude 4 one (for example, 0.1m vs 1m)?&lt;/p&gt;&#xA;" OwnerUserId="28486" LastEditorUserId="6467" LastEditDate="2023-02-14T19:20:19.457" LastActivityDate="2023-02-15T19:30:24.617" Title="How does the Richter earthquake scale translate to the amplitude of horizontal surface movement at the epicenter?" Tags="|earthquakes|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24898" PostTypeId="1" CreationDate="2023-02-15T06:24:17.073" Score="3" ViewCount="24" Body="&lt;p&gt;I am studying the recent paludification (e.g. mineral soil forests turning to peatlands) in a boreal regime. I have collected peat samples from the peat/mineral subsoil contact that have been 14C dated. I have also calculated the slope of the mineral subsoil; a well-known factor controlling the paludification rate (Loisel et al. 2013).&lt;/p&gt;&#xA;&lt;p&gt;However, many studies state that the water logging due to mineral subsoil characteristics is a major cause for paludification but these studies fail to provide any meaningful way to quantify this. The basic principle is neat, for example areas with clay soils and a flat surface are likely to become water-logged.&lt;/p&gt;&#xA;&lt;p&gt;In my study I have collected mineral samples alongside the peat samples that have been taken in transects of 3-4 points. The mineral soil has been collected from the same point location as the peat samples. So I have 3-4 point mineral samples for each transect that represent mineral subsoil for each transects. From these mineral soil samples I have particle size distribution, soil organic matter content (based on Loss-on-ignition) and bulk density.&lt;/p&gt;&#xA;&lt;p&gt;My problem is that I would like to statistically test (possible with generalized linear mixed effect model) if there is any connection between the mineral subsoil characteristics (subsoil, slope, some other variables) and paludification rates but my sample size for paludification is rather small (&amp;lt;50) and thus including all subsoil variables (e.g. clay, silt and sand-%, OM, BD) is not feasible. My question is: Is there a single point value that can be calculated from the variables e.g. soil particle size distribution, organic matter and bulk density that would describe the possible soil water logging?&lt;/p&gt;&#xA;&lt;p&gt;And if not, is there some other approach you would recommend.&lt;/p&gt;&#xA;&lt;p&gt;Reference:&#xA;Quantifying landscape morphology in ﬂ uence on peatland lateral expansion using ground-penetrating radar (GPR) and peat core analysis. (2013) Loisel et al. doi:10.1002/jgrg.20029&lt;/p&gt;&#xA;" OwnerUserId="28490" LastEditorUserId="2470" LastEditDate="2023-02-15T07:20:44.263" LastActivityDate="2023-02-15T07:20:44.263" Title="Can single point value for potential water-logging be calculated using soil particle size, organic matter and bulk density" Tags="|groundwater|soil-science|soil-moisture|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24899" PostTypeId="1" AcceptedAnswerId="24901" CreationDate="2023-02-15T06:43:29.287" Score="30" ViewCount="6695" Body="&lt;p&gt;I was reading about weather balloons and the articles said that weather balloon flights usually last about two hours. When I looked up why, some articles said that when the balloons get high enough in the atmosphere, the balloons pop from the low pressure causing the hydrogen or helium inside the balloon to expand until the balloon popped.&lt;/p&gt;&#xA;&lt;p&gt;My question is: if weather balloons always pop when they reach a certain altitude, why don’t they just make sure the balloon is carrying a payload that is too heavy for the balloon to reach that altitude (or put less hydrogen). If these are used by meteorologists and the like, wouldn’t it be cheaper to just leave the balloons in the sky instead of constantly putting new ones up?&lt;/p&gt;&#xA;" OwnerUserId="21488" LastEditorUserId="2470" LastEditDate="2023-02-15T07:23:53.517" LastActivityDate="2023-02-18T04:00:45.163" Title="Why aren't weather balloons left in the atmosphere permanently?" Tags="|meteorology|atmosphere|temperature|weather-forecasting|weather-satellites|" AnswerCount="6" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24900" PostTypeId="2" ParentId="24899" CreationDate="2023-02-15T07:37:03.603" Score="24" Body="&lt;p&gt;It depends on what each weather balloon is measuring; what data they are capturing.&lt;/p&gt;&#xA;&lt;p&gt;Most weather balloons are released as specific times during a 24 hour cycle. Such balloons measure altitude, temperature, air pressure, humidity, etc. as they rise through the atmosphere. This data is used to get a data cross-section through the atmosphere. This allows meteorologists to obtain a better idea of what is occurring with the atmosphere during the course of the day.&lt;/p&gt;&#xA;&lt;p&gt;Once the balloons have provided this data they've done their job. Constantly supplying data for a specific horizon within the atmosphere, once the balloons have reached their ultimate height is not as useful as knowing the data at various altitudes.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-02-15T07:37:03.603" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24901" PostTypeId="2" ParentId="24899" CreationDate="2023-02-15T14:29:07.670" Score="35" Body="&lt;p&gt;In addition to radiosondes that do a single ascent over a few hours, there are also &lt;strong&gt;driftsondes&lt;/strong&gt; that stay in atmosphere for days or weeks, typically with their buoyancy set up to track a particular pressure level.  They commonly carry a payload of dropsondes that they can deploy periodically to do sampling on the way down, much like a radiosonde does on the way up.  Because these are much larger and more expensive platforms than radiosondes, they are typically used for targeted field campaigns, particularly in places where it would be difficult to launch lots of radiosondes.  For a summary, see Cohn et al (2013) &lt;a href=&quot;https://doi.org/10.1175/BAMS-D-12-00075.1&quot; rel=&quot;noreferrer&quot;&gt;https://doi.org/10.1175/BAMS-D-12-00075.1&lt;/a&gt; and, having been peripherally involved in one of the campaigns they mention, I echo their comment:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Like aircraft dropsonde systems, field experiments using driftsondes involve significant cost and require much advance planning. It can take months to understand likely flight paths and obtain permissions to overfly many countries. If a balloon drifts near a region where overflight permissions have not been granted, then it must be cut down.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In additional to that difficulty, general reasons why driftsondes can’t stay aloft permanently include,&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;All balloons leak, so they can’t stay aloft indefinitely&lt;/li&gt;&#xA;&lt;li&gt;Balloon materials deteriorate, particularly in extreme temperatures&lt;/li&gt;&#xA;&lt;li&gt;Instruments need power, and solar panels add to weight and complexity&lt;/li&gt;&#xA;&lt;li&gt;Finite number of dropsondes aboard, although that’s not the only type of payload&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I notice that (but don’t know much about) the more recent STRATEOLE-2 driftsonde (Haase et al, 2018; &lt;a href=&quot;https://eos.org/science-updates/around-the-world-in-84-days&quot; rel=&quot;noreferrer&quot;&gt;https://eos.org/science-updates/around-the-world-in-84-days&lt;/a&gt;) can stay aloft for around three months, which means it can circle the equator about three times.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2023-02-15T14:29:07.670" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24902" PostTypeId="2" ParentId="24899" CreationDate="2023-02-15T16:38:55.510" Score="8" Body="&lt;p&gt;The vast majority of weather balloons are designed to collect vertical profiles of the nature of the Earth's atmosphere. That would not be possible with a balloon that stays aloft at more or less constant altitude. The US alone launches hundreds of weather balloons every day that rise and rise and rise, but then pop. The popping is intentional. While the payload might need a parachute, the bursted balloon itself does not. Its job is done at the point of popping.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-02-15T16:38:55.510" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24903" PostTypeId="2" ParentId="24899" CreationDate="2023-02-15T17:52:22.820" Score="1" Body="&lt;ol&gt;&#xA;&lt;li&gt;There is no balloon that can stay up indefinitely. The gas will leak from the balloon and the balloon will slowly sink into the air traffic band and then all the way down, going with the wind in the meantime.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Bigger balloons made of better materials will stay longer, but one should design them for some controlled descent in order to prevent air traffic interference.&lt;/p&gt;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;The balloon from the news is not a typical weather balloon.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;The typical weather balloons are used to quickly (in a matter of hours) measure the atmospheric thermal profile (and some other data related to altitude) and then they pop and fall down. They are much, much smaller as well, generally in the range of 2kg or less. The power source for their electronic payload is a small battery that has only so much juice to sustain the intended mission so there is no point of leaving them up.&lt;/p&gt;&#xA;&lt;p&gt;Making them bigger and heavier will simply make them more dangerous for no apparent gain.&lt;/p&gt;&#xA;" OwnerUserId="18660" LastActivityDate="2023-02-15T17:52:22.820" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24904" PostTypeId="2" ParentId="24895" CreationDate="2023-02-15T19:30:24.617" Score="1" Body="&lt;p&gt;The &lt;a href=&quot;https://www.earthquakeauthority.com/Blog/2020/Earthquake-Measurements-Magnitude-vs-Intensity&quot; rel=&quot;nofollow noreferrer&quot;&gt;Richter Scale&lt;/a&gt; for earthquake measurements was replaced by the Moment Magnitude Scale in 1970. People still tend to used the term Richter Scale erroneously because its what they became aware of and they do not know what has replaced it. Additionally, the Richter Scale only applied to a specific type if earthquake in southern California.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;From 1935 until 1970, the earthquake magnitude scale was the Richter scale, a mathematical formula invented by Caltech seismologist Charles Richter to compare quake sizes.&lt;/p&gt;&#xA;&lt;p&gt;The Richter Scale was replaced because it worked largely for earthquakes in Southern California, and only those occurring within about 370 miles of seismometers. In addition, the scale was calculated for only one type of earthquake wave. It was replaced with the Moment Magnitude Scale, which records all the different seismic waves from an earthquake to seismographs across the world.&lt;/p&gt;&#xA;&lt;p&gt;Richter's equations are still used for forecasting future earthquakes and calculating earthquake hazards.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;When &lt;a href=&quot;https://www.britannica.com/science/earthquake-geology/Earthquake-magnitude&quot; rel=&quot;nofollow noreferrer&quot;&gt;Richter&lt;/a&gt; developed his scale in 1935,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Richter first applied his magnitude scale to shallow-focus earthquakes recorded within 600 km of the epicentre in the southern California region.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;By way of comparison,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;the great Alaska earthquake of 1964, with a Richter magnitude (ML) of 8.3, also had the values Ms = 8.4, M0 = 820 × 1027 dyne centimetres, and Mw = 9.2.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The magnitude of an earthquake is more about damaging energy released in a quake than amplitude of a wave.&lt;/p&gt;&#xA;&lt;p&gt;Similarly, shallow earthquake tend to be more damaging than deep earthquakes. So, an earthquake of particular size that is deep will have a different effect to one of the same magnitude that is shallow.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-02-15T19:30:24.617" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24905" PostTypeId="2" ParentId="24899" CreationDate="2023-02-15T19:40:19.783" Score="2" Body="&lt;p&gt;There are such things as zero pressure balloons, they are thin, pliable, and are not a continuous enclosed space, so they auto equalize pressure and work much such like a helium filled parachute.&lt;/p&gt;&#xA;&lt;p&gt;In theory if you could make a material 100% impermeable to helium atoms, and make it in the zero pressure form factor, AND prevent any turbulence at the open end that may scatter and lose helium, you would have a perpetually floating balloon.&lt;/p&gt;&#xA;&lt;p&gt;Such material would also have to be able to withstand extremes in temperature and radiation. Also since they would hover so close to space small debris puncturing it would be a real threat as well as the particles would not have to go through much atmosphere and therefore have less chance to burn up prior to hitting the balloon.&lt;/p&gt;&#xA;&lt;p&gt;So impossible? No. Cost effective? Not even close.&lt;/p&gt;&#xA;&lt;p&gt;Also what happens if you have any equipment malfunction and or want it to come down as new tech evolves? Sure you could have it have a mechanically driven device to cause deflation, provided that is not what malfunctioned ;&lt;/p&gt;&#xA;&lt;p&gt;All in all impractical on all levels.&lt;/p&gt;&#xA;&lt;p&gt;But again, NOT impossible.&lt;/p&gt;&#xA;" OwnerUserId="28495" LastActivityDate="2023-02-15T19:40:19.783" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24906" PostTypeId="2" ParentId="24899" CreationDate="2023-02-15T20:45:46.313" Score="13" Body="&lt;p&gt;There are several reasons for this. One of them is air traffic concerns. The parts of the atmosphere that are interesting for weather (namely, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Troposphere&quot; rel=&quot;noreferrer&quot;&gt;troposhere&lt;/a&gt; and lower &lt;a href=&quot;https://en.wikipedia.org/wiki/Stratosphere&quot; rel=&quot;noreferrer&quot;&gt;stratosphere&lt;/a&gt;) also happen to be the ones in which nearly all aircraft fly. This is why air traffic control is informed and NOTAMs (Notices to Airmen or, as the U.S. now calls them, Notices to Air Missions) are issued when weather balloon operations will take place. For a normal balloon launch, the balloon will only remain at potentially-hazardous altitudes for a matter of minutes (and only a few minutes at the altitudes with the most air traffic density,) so planning air traffic around the launches isn't too big of a deal. However, if the balloon were staying continuously at altitudes where it was collecting useful information, it would also be continuously a hazard to air traffic.&lt;/p&gt;&#xA;&lt;p&gt;An additional reason, as other answers have mentioned, is that the point of weather balloon launches is to collect data for &lt;em&gt;all&lt;/em&gt; altitudes from the surface up to at least the lower portions of the stratosphere, not just one altitude. So, the balloon's flight consisting primarily of a climb phase followed by termination is a feature, not a bug. The radiosonde attached to the balloon collects data such as ambient temperature, dew point, air pressure, wind magnitude, and wind direction for all altitudes. This information then aids meteorologists in determining all kinds of useful information, such as precipitation amount forecasts, potential for thunderstorm development, what type (if any) of precipitation would be expected at the surface, as well as at higher altitudes (for aviation weather forecasting,) depth of different air masses during frontal passage, winds aloft, jet stream position, direction, and magnitude, etc. The data collected by the radiosonde looks like this:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zpyRC.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zpyRC.png&quot; alt=&quot;Radiosonde data from weather balloon&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;Recent Radiosonde data from NWS weather balloon launched from Nashville, TN.&lt;br /&gt;&#xA;Units on the left are air pressure in millibars (with kilometers altitude in red.)&lt;br /&gt;&#xA;Source: &lt;a href=&quot;https://www.spc.noaa.gov/exper/soundings/&quot; rel=&quot;noreferrer&quot;&gt;National Weather Service&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Additionally, balloons are subject to wind. &lt;em&gt;A lot&lt;/em&gt; of wind. Making them stay put in one spot relative to the ground is not so easy, especially in the portions of the atmosphere that are interesting for weather observations, which usually have non-trivial winds aloft, even when the wind is mostly calm at the surface. As seen in the radiosonde data in the picture above, winds aloft were measured up to about 118 knots (136 mph or 219 km/h) in this particular launch. According to the U.S. National Weather Service, even its normal balloon launches &lt;a href=&quot;https://www.weather.gov/bmx/kidscorner_weatherballoons&quot; rel=&quot;noreferrer&quot;&gt;can drift as much as 125 miles (200 km)&lt;/a&gt; during flight. If you just let the balloons free-float indefinitely, then they won't stay where you want them for long, at least not in the interesting parts of the atmosphere. In order to produce reliable, comparable records, the balloons need to be launched at the specified times from the same positions on the ground. Of course, you can tether balloons to the ground in order to make them stay in a mostly-fixed position, but tethers long enough to reach up to 20 km / 65,000 ft or so are not exactly practical and would also greatly magnify the risk posed to air traffic.&lt;/p&gt;&#xA;" OwnerUserId="1099" LastEditorUserId="1099" LastEditDate="2023-02-16T16:43:02.293" LastActivityDate="2023-02-16T16:43:02.293" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24907" PostTypeId="1" AcceptedAnswerId="24950" CreationDate="2023-02-16T02:45:09.253" Score="4" ViewCount="52" Body="&lt;p&gt;I am a marine geology masters student and I am writing my thesis on slow earthquakes. I will include  graphs of the most common types of earthquakes:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Low-frequency earthquakes&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Very low-frequency earthquakes&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Volcanic tremors&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Non-volcanic earthquakes&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Does anyone know where I could get data? If anyone shares with me the above data, I will cite you in my acknowledgement section. Thanks :)&lt;/p&gt;&#xA;" OwnerUserId="27360" LastEditorUserId="6129" LastEditDate="2023-02-16T15:26:58.157" LastActivityDate="2023-02-24T01:54:33.450" Title="Where could I get waveform data on low-frequency earthquakes, very low-frequency earthquakes, volcanic tremor and non-volcanic earthquakes?" Tags="|geophysics|earthquakes|seismology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24908" PostTypeId="1" CreationDate="2023-02-16T08:13:47.853" Score="2" ViewCount="82" Body="&lt;p&gt;An odd discussion came up on a role-playing game forum recently.  Some people were speculating about how a mediaeval society would be different if it had wizards, with the spells described in the game rules.  One of the spells creates heavy rain - the rules specify 1 inch per hour, over a certain area.  Somebody was commenting whether or not this spell would have a big effect on agriculture, and added &amp;quot;unless the crops can't take an inch of rain in an hour, in which case we're looking at this spell all wrong&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;This turns out to be surprisingly difficult to look up.  Maybe I'm looking in the wrong places, but I'm having difficulty finding out how commonplace one inch of rainfall in an hour is or what it actually looks like in practice.  A lot of information about rainfall averaged over a month, and the Met Office classify rainfall greater than 4 mm per hour as &amp;quot;heavy&amp;quot;, but don't say how common &amp;quot;heavy rain&amp;quot; according to this criterion actually is.&lt;/p&gt;&#xA;&lt;p&gt;What does 1 inch of rain per hour mean in practice, how often does that much rain or more happen (say, in the UK), and what would it do to a field of crops?&lt;/p&gt;&#xA;" OwnerUserId="28501" LastActivityDate="2023-02-17T22:32:59.097" Title="Is 1 inch of rain in an hour enough to damage growing crops?" Tags="|meteorology|rainfall|agriculture|rain|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24910" PostTypeId="2" ParentId="24908" CreationDate="2023-02-16T09:16:52.943" Score="3" Body="&lt;p&gt;Just one inch of rain in one hour, and that's it, or an inch of rain per hour that is sustained over multiple days? Keep in mind that rainfall rates of over an inch of rain &lt;em&gt;per minute&lt;/em&gt; have been observed. On the other hand, one inch of rain per hour for two or three straight days, nonstop -- been there, done that, don't want to do it again.&lt;/p&gt;&#xA;&lt;p&gt;Also, time of year is important. If that semi-heavy rainfall (I would not call a rainfall that drops one inch of rain over the course of an hour and then stops a heavy rainfall) falls right after farmers plant their fields or right before they were planning on harvesting, that might be damaging. Farmers expect their seeds to not wash away, and they depend on plants drying out prior to harvest.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2023-02-16T09:22:14.413" LastActivityDate="2023-02-16T09:22:14.413" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24911" PostTypeId="1" CreationDate="2023-02-16T10:04:53.683" Score="1" ViewCount="70" Body="&lt;p&gt;From what I've read about &lt;a href=&quot;https://en.wikipedia.org/wiki/Woody_plant_encroachment&quot; rel=&quot;nofollow noreferrer&quot;&gt;bush encroachment&lt;/a&gt;, it is most often made to sound as a &lt;a href=&quot;https://phys.org/news/2023-02-high-intensity-reverse-bush-encroachment-african.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;bad thing&lt;/a&gt;, potentially as a symptom of land degradation. This sounds counterintuitive to me because bush encroachment actually consists of&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;the expansion of native (as opposed to invasive) plant species, and&lt;/li&gt;&#xA;&lt;li&gt;serves as a carbon sink.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;If anything, it sounds like an ideal case of nature reclaiming its rights, so why would it be a bad thing from a conservation point of view?&lt;/p&gt;&#xA;" OwnerUserId="28503" LastActivityDate="2023-02-17T09:09:53.757" Title="Why is bush encroachement a bad thing?" Tags="|climate-change|environmental-protection|ecology|vegetation|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24912" PostTypeId="2" ParentId="24911" CreationDate="2023-02-16T11:59:30.137" Score="2" Body="&lt;p&gt;As with many situations there are positives and negatives. With bush encroachment the positives include expanding the range of native species, acting as a carbon sink, it can lead to natural reforestation. It can also increase the habitat for certain animals and potentially reduce erosion and help limit desertification. There is also the potential to increase ground cover, cool the land surface and retain soil moisture. In some situations it can even reduce the height of the water table and thus reduce salinity  of the land by keeping salt deeper down, below the depth to which plant root go down.&lt;/p&gt;&#xA;&lt;p&gt;On the negative side of things, increasing bush cover reduces the amount of savanna in a region. Some animals depend on savanna for survival and thus encroachment of bush would be detrimental to them because it reduces their habitat, which in turn alters the dynamics of fauna in the region.&lt;/p&gt;&#xA;&lt;p&gt;In the long term, in certain situations, this can turn out to be detrimental overall if the numbers of predator species are reduced too much and the number of prey species can become too much and they could overgraze an area ultimately leading to desertification and erosion. It all depends on the species affected by bush encroachment.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, changing a landscape from savanna to bush increases the potential for more destructive wildfires. Wooded landscapes burn at higher temperatures, which can affect the nutrient levels of soil, produce large burn scars which could increase the possibility of desertification and it can lead to a greater loss of life of flora and fauna.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2023-02-16T12:19:29.300" LastActivityDate="2023-02-16T12:19:29.300" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24913" PostTypeId="1" CreationDate="2023-02-16T13:20:46.707" Score="1" ViewCount="60" Body="&lt;p&gt;An ice day is a day on which the maximum temperature doesn't exceed 0 °C and a tropical night is a night on which the minimum temperature exceeds 20 °C. Probably no part of the tropics has experienced an ice day and most continental locations far north haven't experienced a tropical night. My guess is that a location that has experienced neither would have to be coastal or an island in the mid-latitudes: Eureka, California, is one example (the coldest day was 1°C and the warmest night 17 °C). Campbell island (NZ) and Tristan Da Cunha might also be examples, but I couldn't find exact data to prove it.&lt;/p&gt;&#xA;" OwnerUserId="28506" LastEditorUserId="28506" LastEditDate="2023-02-28T18:48:03.950" LastActivityDate="2023-02-28T18:48:03.950" Title="What are some places that have never recorded an &quot;ice day&quot; nor a &quot;tropical night&quot;?" Tags="|climate|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24916" PostTypeId="2" ParentId="24911" CreationDate="2023-02-17T09:09:53.757" Score="1" Body="&lt;p&gt;This answer is based on my knowledge on the tundra regime, where bush/shrub encroachment is also happening.&lt;/p&gt;&#xA;&lt;p&gt;In these areas the expansion of shrub coverage replaces existing vegetation such as lichen and moss-dominated plant communities leading which causes large changes in tundra biome.&lt;/p&gt;&#xA;&lt;p&gt;Although the shrub vegetation itself acts as a carbon sink the effect of vegetation change causes decreases albedo e.g., the darker shrub vegetation absorbs warmth from the sunlight compared to the lighter lichens, mosses, bare ground (and plain snow-cover) that reflect the solar radiance. Thus the effect of shrub encroachment can have warming effect on the climate (that may or may not exceed the increased carbon sink of shrub vegetation, still under a debate I think).&lt;/p&gt;&#xA;&lt;p&gt;Wildfires were already mentioned, but they might increase also in the northern areas. In addition, the ground temperatures and thus microbial activity could change, leading for example to a increased decomposition and nutrient cycling.&lt;/p&gt;&#xA;&lt;p&gt;For tundra ecosystems see f.e. Shrub expansion in tundra ecosystems:&#xA;dynamics, impacts and research priorities (2011). Myers-Smith et. Environ. Res. Lett. 6 (2011) 045509&lt;/p&gt;&#xA;" OwnerUserId="28490" LastActivityDate="2023-02-17T09:09:53.757" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24917" PostTypeId="1" CreationDate="2023-02-17T11:11:36.310" Score="4" ViewCount="37" Body="&lt;p&gt;We have lots of data measured by weather stations in our network, but unfortunately their temporal coverage is not sufficient to compute a full 30 years climatology (e.g. over the 1991-2020 period). However, we still want to compute some reference for the station which will allow us to get an idea on how warmer/colder or drier/wetter a certain period (week, month, season, year...) was.&lt;/p&gt;&#xA;&lt;p&gt;I came up with a cool trick, that I believe someone else in the literature used, although I could not find evidence anywhere. Using reanalysis (&lt;code&gt;ERA5-Land&lt;/code&gt;) data on a period where I have coverage from both model and station data I can attempt to build a relationship that links the two: can be something simple from a linear regression to something more complicated like find a SVM model that fits the closest grid points values from the reanalysis to the station data.&lt;/p&gt;&#xA;&lt;p&gt;Once this &amp;quot;model&amp;quot; is found, I can use it on the reanalysis data of the period 1991-2020 to get, as output, a &amp;quot;fictitious&amp;quot; climatology for the station. This works pretty well for temperature, as it has a clear seasonal cycle and no distinct day-to-day variability, but fails completely to capture the precipitation sudden changes, maybe also due to the fact that reanalysis are hardly capturing local precipitation features.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tZzW3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tZzW3.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Does anyone have useful resources/ideas that could help me in improving the model?&lt;/p&gt;&#xA;" OwnerUserId="27107" LastActivityDate="2023-02-17T11:11:36.310" Title="Reconstructing the climatology of a station using reanalysis" Tags="|meteorology|climatology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24919" PostTypeId="1" CreationDate="2023-02-17T19:37:35.767" Score="2" ViewCount="38" Body="&lt;p&gt;Companies like tomorrow.io are &lt;a href=&quot;https://www.tomorrow.io/space/&quot; rel=&quot;nofollow noreferrer&quot;&gt;promising&lt;/a&gt; satellite-based weather radar. However, I can easily imagine several flaws (especially in combination with the greater distance to storms than a ground-based radar):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Limited power?&lt;/li&gt;&#xA;&lt;li&gt;Limited SNR?&lt;/li&gt;&#xA;&lt;li&gt;Potential interference?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;It's unclear to me how realistic these potential flaws are; I give them solely as examples. My question is: excluding engineering/economic disadvantages, &lt;strong&gt;are there physics-based disadvantages to having a space-based weather radar compared to a ground-based radar?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="18405" LastActivityDate="2023-02-17T19:37:35.767" Title="Limitations of satellite radar for precipitation measurement?" Tags="|meteorology|weather-satellites|radar|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24920" PostTypeId="2" ParentId="21337" CreationDate="2023-02-17T21:27:19.137" Score="1" Body="&lt;p&gt;One center that has been overlooked is the center of the smallest circle that can be drawn the entirety of an area. Start by finding the center of the circle that just touches the extreme cardinal points north, south, east, west of an area and then find the points of the area that overlap the circle.2 of those points will take the place of 2 of the cardinal points.&lt;/p&gt;&#xA;" OwnerUserId="28159" LastActivityDate="2023-02-17T21:27:19.137" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24921" PostTypeId="1" AcceptedAnswerId="24931" CreationDate="2023-02-17T22:02:36.870" Score="2" ViewCount="49" Body="&lt;p&gt;I'm working through Artifaxian's (&lt;a href=&quot;https://www.youtube.com/watch?v=AzD_WVsEIRM&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=AzD_WVsEIRM&lt;/a&gt;) series on using gPlates to make tectonic history.  I've run into the place where I have two subduction ridges about to meet.  The bottom continent is moving up, the one at the top is moving down. Which one is likey to subduct?&lt;/p&gt;&#xA;&lt;p&gt;I can imagine that the unified front of the bottom subduction could make it easier for it to take under the top subduction zone.  Likewise I could imagine that the sharp point could pierce the bottom one.&lt;/p&gt;&#xA;&lt;p&gt;The ocean crust segments are the same age.&lt;/p&gt;&#xA;&lt;p&gt;Thanks for any thoughts and ideas you share!&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hyIZx.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hyIZx.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28516" LastEditorUserId="28516" LastEditDate="2023-02-17T22:03:42.103" LastActivityDate="2023-02-20T00:18:40.233" Title="Speculative Plate Techtonics - Resolving intersecting subductions" Tags="|geology|plate-tectonics|tectonics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24922" PostTypeId="2" ParentId="24908" CreationDate="2023-02-17T22:32:59.097" Score="1" Body="&lt;p&gt;There are crops that do require periods with little or no rain to be successful. A wheat crop for example can be ruined or degraded by untimely rainfall; dry conditions are needed for the wheat seeds to mature and the wheat heads need to be dry for harvesting.&lt;/p&gt;&#xA;&lt;p&gt;Whilst not affecting plant growth, hay crops can be ruined by rainfall between the cutting and baling - it needs time without rain to dry out.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2023-02-17T22:32:59.097" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24924" PostTypeId="1" CreationDate="2023-02-18T06:58:08.213" Score="1" ViewCount="52" Body="&lt;p&gt;I have a small inquiry about the setup of some variables in 'namelist.input' file for running WRF-Chem to study aerosol-cloud-climate interaction. After going through various research papers on aerosol-cloud interaction studies using the WRF-Chem model, the user guides, and tutorial presentations available on the WRF-Chem official webpage, I noticed that the cumulus parameterization scheme is not used if the resolution of the domain is 4 km or less than 4 km. Then, if I set the resolution of my d02 as 4 km, should the options &amp;quot;cu_physics&amp;quot; be set to &amp;quot;0&amp;quot; and &amp;quot;cu_rad_feedback&amp;quot; be set to &amp;quot;false&amp;quot; for that domain?&lt;/p&gt;&#xA;&lt;p&gt;I also learned that to study the aerosol indirect effect, the options &amp;quot;wetscav_onoff&amp;quot; and &amp;quot;cldchem_onoff&amp;quot; should be set to 1. And it is mentioned in the &amp;quot;Best Practices for Applying WRF-Chem 3.9.1.1&amp;quot; tutorial presentation that in the &amp;quot;chem&amp;quot; section of the namelist, &amp;quot;conv_tr_aqchem&amp;quot; and &amp;quot;conv_tr_wetscav&amp;quot; should be set to 1 to include aqueous chemistry and convective wet scavenging. So, what should I set for the options &amp;quot;chem_conv_tr&amp;quot;, &amp;quot;conv_tr_wetscav&amp;quot;, and &amp;quot;conv_tr_aqchem&amp;quot; for d02 (4 km)? &amp;quot;0&amp;quot; or &amp;quot;1&amp;quot;'? Could someone please help me sort this out? It will be very helpful for me. Thank you for your time and consideration.&#xA;With regards,&#xA;Ankan&lt;/p&gt;&#xA;" OwnerUserId="28246" LastActivityDate="2023-02-18T06:58:08.213" Title="Query on the 'namelist.input' file for running WRF-Chem to study aerosol-cloud-climate interaction" Tags="|meteorology|numerical-modelling|wrf-chem|aerosol|cloud-microphysics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24925" PostTypeId="1" CreationDate="2023-02-18T08:42:59.667" Score="1" ViewCount="49" Body="&lt;p&gt;Hi I need a simple equation (polynomial third straight) for a PerpleX simulation to represent the mantle geotherm. The geotherms  I have found on the internet so far (unfortunately I don't have the websites anymore) were all too complex for me to use for my simulation. Do any of you know suitable literature or have you written a geotherm gradient for PerpleX?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2023-02-18T11:45:05.330" Title="Simple Mathematical Equation for the Geotherm" Tags="|geophysics|geothermal-heat|mantle|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24928" PostTypeId="1" CreationDate="2023-02-18T17:28:37.987" Score="4" ViewCount="122" Body="&lt;p&gt;What is the average temperature of the Earth when you take into account all of the layers, not just the surface? Everything I've found so far concern only the surface or each layer individually. But what if you take the (weighted) average of all layers? And how is it calculated? &lt;a href=&quot;https://astronomy.stackexchange.com/a/27260&quot;&gt;This answer&lt;/a&gt; seems to indicate that the weights should be the heat capacity:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$T_{Earth} = \frac{\iiint_{Earth} C\,T\,dV}{\iiint_{Earth} C\,dV} = \frac{\int_0^R 4\pi r^2\,C(r)\,T(r)\,dr}{\int_0^R 4\pi r^2\,C(r)\,dr}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;(This is a duplicate of a closed &lt;a href=&quot;https://astronomy.stackexchange.com/questions/27252/what-is-earths-average-temperature-as-a-whole&quot;&gt;question&lt;/a&gt; posted on the Astronomy Stack Exchange)&lt;/p&gt;&#xA;" OwnerUserId="11611" LastActivityDate="2023-02-24T12:35:01.740" Title="What is the average temperature of the whole planet Earth, not just the surface?" Tags="|temperature|geothermal-heat|thermodynamics|geologic-layers|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24929" PostTypeId="1" AcceptedAnswerId="24930" CreationDate="2023-02-18T17:47:16.830" Score="2" ViewCount="85" Body="&lt;p&gt;I'm a student of meteorology in first year. This time my question is not about a particular problem I have, but rather about teaching and learning: In a recent lecture on atmospheric dynamics we learned among other things the &amp;quot;vorticity equation&amp;quot;: Its derivation was carried out starting from the horizontal momentum equations:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nTSJV.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nTSJV.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;After taking the y derivative of the u equation and the x derivative of the v equation and subtracting them, we get a lot of terms, which were grouped together and partially cancel each other. After a struggling time, we end up finally in the vertical component &lt;span class=&quot;math-container&quot;&gt;$\zeta $&lt;/span&gt; of the vorticity &lt;span class=&quot;math-container&quot;&gt;$\vec \omega $&lt;/span&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/D8jaS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/D8jaS.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Note: the pictures of the equations above are taken from YouTube: &lt;a href=&quot;https://www.youtube.com/watch?v=lqDx2uiKx_Q&amp;amp;list=PL_cuIb7hx5lg_zHfUVsUrw6I66U4jq8Dq&amp;amp;t=163s&quot; rel=&quot;nofollow noreferrer&quot;&gt;AtmosphericDynamics Chapter04 Part02 VorticityEquation&lt;/a&gt;, but they were identical in the lecture (the derivation was skipped in the video).&lt;/p&gt;&#xA;&lt;p&gt;Now I have found the following after my own search, whereby the derivation is a lot easier (see chapter 3.4.) of &lt;a href=&quot;https://www2.cgd.ucar.edu/staff/islas/teaching/3_Circulation_Vorticity_PV.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Vorticity, Circulation and Potential Vorticity&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;(see 3.4)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HVMFq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HVMFq.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This approach, using well know vector identities is independent of the coordinate system and gives to my surprise really the same result for &lt;span class=&quot;math-container&quot;&gt;$D \zeta/Dt$&lt;/span&gt; although it looks totally different at the first sight (I ignore the friction term).&lt;/p&gt;&#xA;&lt;p&gt;In Holton, a book which I like very much, the derivation is essentially the same as in our lecture: quite log and non-motivating, because so many partial derivative terms had to be arranged and grouped with each other to get the final result after doing some pages of simple but totally boring algebra. Contrary, the other derivation is not only shorter, but more elegant in terms of vector analysis and gives in only a few steps the generic result for all components of &lt;span class=&quot;math-container&quot;&gt;$\vec \omega$&lt;/span&gt;, not only for &lt;span class=&quot;math-container&quot;&gt;$\zeta$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Why this completely cumbersome derivation and not doing the same as in the other text, which is much more appealing and more general?&lt;/p&gt;&#xA;&lt;p&gt;Is there a particular reason to write the final equation in a rather &amp;quot;nasty&amp;quot; way in local cartesian coordinates instead using the generic variant? It would have been more fun and more motivating to learn it in the other way around from the beginning.&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2023-02-19T12:44:19.183" LastActivityDate="2023-02-19T16:07:41.527" Title="Why are there different Notations of Vorticity Equation?" Tags="|meteorology|atmosphere-modelling|fluid-dynamics|vorticity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24930" PostTypeId="2" ParentId="24929" CreationDate="2023-02-19T15:59:43.520" Score="4" Body="&lt;p&gt;The first equation is presented when the vector identities are not used. That is when students may not have knowledge of advanced vector algebra, for example, curls, dot and cross products, eigenvalues and eigenvectors. The second uses vector identity concepts. While the first is given to undergraduate courses because it doesn't require the concept of advanced vector algebra, the second is given to senior level undergrads and graduate classes as it requires advanced concepts of vector algebra.&lt;/p&gt;&#xA;" OwnerUserId="4877" LastEditorUserId="4877" LastEditDate="2023-02-19T16:07:41.527" LastActivityDate="2023-02-19T16:07:41.527" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24931" PostTypeId="2" ParentId="24921" CreationDate="2023-02-20T00:18:40.233" Score="3" Body="&lt;p&gt;If two continental plates meet, neither generally subduct -- you just get a big collision, in the way the Alps and the Himalayas are formed. That's because continental plates are relatively light, and neither wants to disappear into the mantle.&lt;/p&gt;&#xA;&lt;p&gt;If a continental and an oceanic plate meet, the oceanic plate (being denser) generally loses the battle and subducts. If two oceanic plates meet, it's a toss-up.&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2023-02-20T00:18:40.233" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24932" PostTypeId="1" CreationDate="2023-02-20T01:18:38.017" Score="1" ViewCount="14" Body="&lt;p&gt;How to add more outdoor weather sensors to Software Defined Radio (Weather Station) ?&lt;/p&gt;&#xA;&lt;p&gt;I am looking for seismographic outdoor radio sensors to work for Software Defined Radio (Weather Station).&lt;/p&gt;&#xA;&lt;p&gt;So frankly speaking I need to modify the existing outdoor radio sensors to detect seismography.&lt;/p&gt;&#xA;&lt;p&gt;Most smartphones come with accelerometer sensors but it's hard to have smartphone to be operated outdoor or to be burried in the ground in your backyard.&lt;/p&gt;&#xA;&lt;p&gt;Let me know your working solution to my problem&lt;/p&gt;&#xA;&lt;p&gt;There is a nice question and answer from the past but I am looking for working hardware / software solution&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;&#xA;Detecting seismic waves using Software Defined Radio&lt;/p&gt;&#xA;&lt;p&gt;I understand about physic and waves, but I am a totally rookie in this topic. I was wondering which are the typical frequency ranges of the S-waves, P-waves and surface waves. My idea would be to detect any seismic event using Software Defined Radio, but I am not sure at all If ...&#xA;asked Aug 20, 2016 at 21:44 by Cod1ngFree&lt;/p&gt;&#xA;" OwnerUserId="28526" LastActivityDate="2023-02-20T01:18:38.017" Title="How to add more outdoor weather sensors to Software Defined Radio (Weather Station)" Tags="|meteorology|earthquakes|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24933" PostTypeId="2" ParentId="24928" CreationDate="2023-02-20T05:42:03.640" Score="7" Body="&lt;p&gt;&lt;strong&gt;TL;DR:&lt;/strong&gt;&#xA;Approximately &lt;span class=&quot;math-container&quot;&gt;$2700\,\text K$&lt;/span&gt; (&lt;span class=&quot;math-container&quot;&gt;$2400\text{°C}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$4400\text{°F}$&lt;/span&gt;)&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Assuming that the weights are indeed the heat capacity per unit volume &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; and that &lt;span class=&quot;math-container&quot;&gt;$C \approx \rho C_P$&lt;/span&gt;, where &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; is the density and &lt;span class=&quot;math-container&quot;&gt;$C_P$&lt;/span&gt; is the specific heat capacity at constant pressure, we can calculate the average temperature by the formula:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\begin{align}&#xA;T_{Earth} &amp;amp;= \frac{\iiint_{Earth} C\,T\,dV}{\iiint_{Earth} C\,dV} = \frac{\int_0^R 4\pi r^2\,C(r)\,T(r)\,dr}{\int_0^R 4\pi r^2\,C(r)\,dr} \\&#xA;&amp;amp;= \frac{\int_0^R r^2\,C(r)\,T(r)\,dr}{\int_0^R r^2\,C(r)\,dr}&#xA;\end{align}&#xA;$$&lt;/span&gt;&#xA;In &lt;a href=&quot;https://www.cambridge.org/core/books/physics-of-the-earth/05CC5483F1DD8FCC2604C550946AC2E6&quot; rel=&quot;nofollow noreferrer&quot;&gt;Physics of the Earth&lt;/a&gt; by Stacey &amp;amp; Davis [1] we find a table of &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; (Table F.1, pp. 469-471), and a table of &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$C_P$&lt;/span&gt; (Table G.1, pp. 472-473).&lt;/p&gt;&#xA;&lt;p&gt;We approximate &lt;span class=&quot;math-container&quot;&gt;$C(r)$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$T(r)$&lt;/span&gt; by piecewise affine functions where each interval &lt;span class=&quot;math-container&quot;&gt;$r \in [r_n, r_{n+1}]$&lt;/span&gt; gives the following approximations:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;C(r) \approx C_n + \frac{r - r_n}{r_{n+1} - r_n}\cdot (C_{n+1} - C_n) \\&#xA;T(r) \approx T_n + \frac{r - r_n}{r_{n+1} - r_n}\cdot (T_{n+1} - T_n)&#xA;$$&lt;/span&gt;&#xA;So the integral in the numerator can be approximated by (according to &lt;a href=&quot;https://www.wolframalpha.com/input?i=integral%20from%20r1%20to%20r2%20of%20r%5E2*%28C1%20%2B%20%28r-r1%29*%28C2-C1%29%2F%28r2-r1%29%29*%28T1%20%2B%20%28r-r1%29*%28T2-T1%29%2F%28r2-r1%29%29*dr&quot; rel=&quot;nofollow noreferrer&quot;&gt;WolframAlpha&lt;/a&gt;):&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\int_0^R r^2\,C(r)\,T(r)\,dr \\&#xA;\approx \sum_{n=1}^{N-1} \int_{r_n}^{r_{n+1}} r^2 \left(C_n + \frac{r - r_n}{r_{n+1} - r_n}\cdot (C_{n+1} - C_n)\right) \left(T_n + \frac{r - r_n}{r_{n+1} - r_n}\cdot (T_{n+1} - T_n)\right) \, dr \\&#xA;= \sum_{n=1}^{N-1} \frac{1}{60}(r_{n+1}-r_n)\left\{ C_n \left[3 r_n^2 (4 T_n + T_{n+1}) + r_n r_{n+1} (6 T_n + 4 T_{n+1}) + r_{n+1}^2 (2 T_n + 3 T_{n+1})\right] + C_{n+1} \left[r_n^2 (3 T_n + 2 T_{n+1}) + r_n r_{n+1} (4 T_n + 6 T_{n+1}) + 3 r_{n+1}^2 (T_n + 4 T_{n+1})\right]\right\}&#xA;$$&lt;/span&gt;&#xA;And the denominator becomes (according to &lt;a href=&quot;https://www.wolframalpha.com/input?i=integral%20from%20r1%20to%20r2%20of%20r%5E2*%28C1%20%2B%20%28r-r1%29*%28C2-C1%29%2F%28r2-r1%29%29*dr&quot; rel=&quot;nofollow noreferrer&quot;&gt;WolframAlpha&lt;/a&gt;):&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\int_0^R r^2\,C(r)\,dr \\&#xA;\approx \sum_{n=1}^{N-1} \int_{r_n}^{r_{n+1}} r^2 \left(C_n + \frac{r - r_n}{r_{n+1} - r_n}\cdot (C_{n+1} - C_n)\right) \, dr \\&#xA;= \sum_{n=1}^{N-1} \frac{1}{12} (r_{n+1} - r_n) \left[ r_n^2 (3 C_n + C_{n+1}) + 2 r_n r_{n+1} (C_n + C_{n+1}) + r_{n+1}^2 (C_n + 3 C_{n+1})\right]&#xA;$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now we can write these expressions in a &lt;a href=&quot;https://docs.google.com/spreadsheets/d/1wGtwVJboFD6Tay_arlQmh_pub3EVGubz/&quot; rel=&quot;nofollow noreferrer&quot;&gt;spreadsheet&lt;/a&gt; with the values from [1] and sum them over then divide the results to get the final answer:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\begin{align}&#xA;T_{Earth} &amp;amp;\approx 2692\,\text K \\&#xA;&amp;amp;= 2419\text{°C} \\&#xA;&amp;amp;= 4386\text{°F}&#xA;\end{align}&#xA;$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;[1] Stacey, F., &amp;amp; Davis, P. (2008). Physics of the Earth (4th ed.). Cambridge: Cambridge University Press. doi:10.1017/CBO9780511812910&lt;/p&gt;&#xA;" OwnerUserId="11611" LastEditorUserId="11611" LastEditDate="2023-02-24T12:35:01.740" LastActivityDate="2023-02-24T12:35:01.740" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24934" PostTypeId="1" CreationDate="2023-02-20T17:19:25.057" Score="2" ViewCount="111" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gpdef.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gpdef.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I was going through an old Indian survey map, when I saw this unfamiliar relief feature. It looked like a cross between a hachure and saddle. Could someone help identify it?&lt;/p&gt;&#xA;" OwnerUserId="28530" LastActivityDate="2023-02-20T17:19:25.057" Title="What is this mountainous relief feature?" Tags="|mountains|topography|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24935" PostTypeId="2" ParentId="24877" CreationDate="2023-02-21T09:09:35.597" Score="0" Body="&lt;p&gt;The specific humidity is the ratio of the mass of water vapor to the total mass of the air parcel. The absolute humidity is the mass of the water vapor by the volume of the air parcel. To connect both, you simply need the density of air, which you can estimate from the height above ground by assuming some standard atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;So, you can not, without further assumptions calculate the specific humidity by using absolute humidity and height above ground, but you can get a fair estimate using some standard assumption.&lt;/p&gt;&#xA;" OwnerUserId="28529" LastEditorUserId="2470" LastEditDate="2023-02-21T09:59:45.423" LastActivityDate="2023-02-21T09:59:45.423" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24936" PostTypeId="1" CreationDate="2023-02-21T10:18:16.540" Score="3" ViewCount="67" Body="&lt;p&gt;I am watching &lt;a href=&quot;https://en.wikipedia.org/wiki/NHK_World-Japan&quot; rel=&quot;nofollow noreferrer&quot;&gt;NHK World-Japan&lt;/a&gt;'s documentary &lt;a href=&quot;https://www.youtube.com/watch?v=BEi32c7Prv4&quot; rel=&quot;nofollow noreferrer&quot;&gt;The Mystery Of The 40 Meter Tsunami&lt;/a&gt;, which analyzes the 40.5-meter tsunami at &lt;a href=&quot;https://en.wikipedia.org/wiki/Miyako,_Iwate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Miyako, Iwate&lt;/a&gt; that occurred during the &lt;a href=&quot;https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami&quot; rel=&quot;nofollow noreferrer&quot;&gt;2011 Tōhoku earthquake and tsunami&lt;/a&gt;. They mention authorities plan to install underwater gauges to assess the water pressure to estimate the tsunami height in the future, to avoid getting blindsided as they did in 2011.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9nkp4.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9nkp4.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The gauges are placed &lt;a href=&quot;https://youtu.be/BEi32c7Prv4?t=2575&quot; rel=&quot;nofollow noreferrer&quot;&gt;as follows&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Ax2eZ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ax2eZ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Why not place gauges in a straight line instead of zigzags?&lt;/p&gt;&#xA;" OwnerUserId="587" LastActivityDate="2023-02-21T14:00:11.053" Title="Why not place tsunami-height-prediction gauges in a straight line instead of zigzags?" Tags="|tsunami|japan|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24937" PostTypeId="2" ParentId="24936" CreationDate="2023-02-21T14:00:11.053" Score="1" Body="&lt;p&gt;I think this comes down to a question of perspective.&lt;/p&gt;&#xA;&lt;p&gt;You see zigzags, yes I see them too, but I also see numerous straight lines connected as a loop.&lt;/p&gt;&#xA;&lt;p&gt;Looking at the big loop, I see 20 sub-perpendicular lines radiating out from the coast. Each line is approximately straight. I've marked them in red in the picture below. The yellow line marks the return of the loop. It would also act as an initial warning sensor line. Each sensor on the yellow line would more or less line up with one of the red lines and thus serve to extend each of the red lines.&lt;/p&gt;&#xA;&lt;p&gt;Regarding sensors on the lines connecting the ends of the red line, why not? It's potentially more data, that could be useful.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bidkI.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bidkI.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-02-21T14:00:11.053" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24938" PostTypeId="1" CreationDate="2023-02-21T22:15:04.183" Score="2" ViewCount="57" Body="&lt;p&gt;As an ordinary person without a science background, I did a bit of research into if microplastics are harmful. I've found 9 articles, and I've summarised my findings in my own words:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Microplastics are ubiquitous, but we don’t know much about their harm. We know they can be carriers of harmful chemicals that remain on the plastic, including carcinogenic chemicals. They can be microscopic and nanoscopic in scale, potentially entering cells on an atomic level. They are easily carried across food chains, persist in our environment, and will never biodegrade and only get smaller and smaller. If large enough, they can be ingested like bigger plastics and cause harm to organisms, in particular to marine life.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Some of the articles I read to produce this summary: &lt;a href=&quot;https://earth.org/microplastics-pollution-in-the-marine-environment-and-its-climate-implications-how-to-overcome-the-impacts/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ref1&lt;/a&gt;, &lt;a href=&quot;https://www.nature.com/articles/d41586-021-01143-3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ref2&lt;/a&gt;, &lt;a href=&quot;https://education.nationalgeographic.org/resource/microplastics/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ref3&lt;/a&gt;, &lt;a href=&quot;https://earth.org/are-microplastics-harmful/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ref4&lt;/a&gt;, &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0160412020322297#:%7E:text=For%20the%20first%20time%20microplastics,Raman%20microspectroscopy%20in%20human%20placentas.&amp;amp;text=Microplastics%20were%20found%20in%20all,maternal%2C%20fetal%20and%20amniochorial%20membranes.&amp;amp;text=Microplastics%20carry%20with%20them%20substances,term%20effects%20on%20human%20health.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ref5&lt;/a&gt;, &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S014111361630112X&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ref6&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;If this is correct, I think the problem is not microplastics, but the chemicals on them. As long as microplastics are small enough to not cause any physical damage (suffocation, entanglement, laceration, internal injuries, usually caused by larger plastics), we can let them continue to break into smaller pieces without harm. Do you agree? Do you think there are much more harmful effects yet to be discovered?&lt;/p&gt;&#xA;&lt;p&gt;NOTE: In the back of my mind, I am thinking about synthetic clothing / textiles. If my suggestion is correct, then synthetic clothing is potentially harmless as long as they are not treated with harmful chemicals – we do no need to worry about the shedding of microplastics.&lt;/p&gt;&#xA;&lt;p&gt;NOTE: Apologies, I know there are many types of plastics out there. This is something I know little about. Please feel free to say more on this.&lt;/p&gt;&#xA;" OwnerUserId="28534" LastEditorUserId="28534" LastEditDate="2023-02-21T22:26:16.763" LastActivityDate="2023-02-21T22:26:16.763" Title="Are microplastics harmful or just the chemicals on them?" Tags="|plastic|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="24939" PostTypeId="1" CreationDate="2023-02-22T00:52:17.000" Score="6" ViewCount="85" Body="&lt;p&gt;I'm looking for glacier data that provides the velocity at different heights within a glacier. So, ideally I would like data that includes not only velocity at the surface, but also velocity at at different distances below the surface. Figure 2 on page 5 &lt;a href=&quot;https://glaciers.gi.alaska.edu/sites/default/files/Notes_icesheetmod_Bueler2014.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; made me think that I could find velocity at different height values for some glacier. Am I interpreting this graph incorrectly? I'm very new to glaciology.&lt;/p&gt;&#xA;&lt;p&gt;I read up on the use of inclinometers, which I think could be used to get the type of measurements that I want (again, I'm very new to this, so I could be wrong). However, I searched the databases &lt;a href=&quot;https://nsidc.org/apps/itslive/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, and &lt;a href=&quot;https://nsidc.org/data/search#keywords=glaciers&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; and I could not find any data like what I'm looking for. I can find the surface velocity for the different glaciers, but not the velocity at different depths below the surface of the glaciers.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Does data giving ice velocity at different heights within the glacier exist?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Do we have this type of data for a glacier that could be modeled as a parallel sided slab on slope problem? My main purpose is that I would like some real-world velocity vs &lt;span class=&quot;math-container&quot;&gt;$z$&lt;/span&gt;-coordinate (height) data that I can plot for the parallel-sided slab on slope problem.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Even if you can't tell me where to find this data just knowing if there's a possibility it exists would be very helpful. Thanks!&lt;/p&gt;&#xA;" OwnerUserId="28536" LastEditorUserId="28536" LastEditDate="2023-02-22T16:22:17.633" LastActivityDate="2023-03-01T16:06:30.457" Title="Is There Data Describing the Velocity of Different Heights of a Glacier?" Tags="|glaciology|open-data|climate-data|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24940" PostTypeId="2" ParentId="17465" CreationDate="2023-02-22T09:34:55.117" Score="5" Body="&lt;p&gt;Technically (at least in solar energy industry):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Irradiance&lt;/strong&gt; is the instant power of solar radiation per unit area, it is measured in &lt;strong&gt;W/m2&lt;/strong&gt; (it is instantaneous, therefore no time dimension in the units).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;strong&gt;Irradiation&lt;/strong&gt; is the &lt;strong&gt;quantity&lt;/strong&gt; of solar energy per unit area, measured in &lt;strong&gt;Wh/m2/time&lt;/strong&gt; (day or year or so; time dimension here is relevant).&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Practically, the terms are often confused.&lt;/p&gt;&#xA;" OwnerUserId="28538" LastEditorUserId="28538" LastEditDate="2023-02-27T07:55:54.243" LastActivityDate="2023-02-27T07:55:54.243" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="24941" PostTypeId="2" ParentId="24939" CreationDate="2023-02-22T21:12:22.807" Score="4" Body="&lt;p&gt;There are many measurements presented in the literature of the velocity profile of a glacier. However, since all profiles will to some extent be dependent on local conditions, I am not sure how useful they will be. A simple alternative would then be to follow the flow profile presented by Nye (1952) where the velocity at some depth &lt;em&gt;u&lt;/em&gt;_z in a glacier is related to the surface &lt;em&gt;u&lt;/em&gt;_s as (using pseudo-LaTeX syntax):&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;u_z - u_s = 2A/(n-1) (rga)^n H^(n+1)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;where &lt;em&gt;A&lt;/em&gt; is a viscosity related constant (site specific), &lt;em&gt;n&lt;/em&gt; = 3, &lt;em&gt;r&lt;/em&gt; is the density of ice (900 kg/m^3), &lt;em&gt;g&lt;/em&gt; is the gravitational constant, &lt;em&gt;a&lt;/em&gt; is the surface slope of the glacier and &lt;em&gt;H&lt;/em&gt; is the thickness of the glacier.&lt;/p&gt;&#xA;&lt;p&gt;The equation allows you to produce a velocity profile from a given set of values of surface slope and ice thickness related to a surface velocity.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Reference:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Nye, J.F. 1952. Mechanics of glacier flow. Journal of Glaciology, 2 (12), 82–93.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="81" LastEditDate="2023-03-01T16:06:30.457" LastActivityDate="2023-03-01T16:06:30.457" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24942" PostTypeId="1" AcceptedAnswerId="24947" CreationDate="2023-02-22T21:24:50.360" Score="3" ViewCount="102" Body="&lt;p&gt;I remember reading about a substance - I think it was a metal - left behind by meteorite impacts and nuclear explosions, but I can't remember the name. What is the name of the substance left behind by nuclear explosions and meteorite impacts?&lt;/p&gt;&#xA;" OwnerUserId="28541" LastActivityDate="2023-02-25T08:22:14.597" Title="What is the metal left behind by meteorites called?" Tags="|geology|meteorite|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24943" PostTypeId="1" AcceptedAnswerId="24946" CreationDate="2023-02-22T21:31:06.310" Score="6" ViewCount="843" Body="&lt;p&gt;This images are of Mt. Kailash, Himalaya.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Front face of Mount:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/EBdXn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EBdXn.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Back face of Mount:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SN5vN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SN5vN.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28542" LastEditorUserId="28542" LastEditDate="2023-02-23T13:46:14.093" LastActivityDate="2023-03-11T16:30:21.963" Title="What are these geological horizontal lines formed on this mountain called and why they are formed?" Tags="|geology|mountains|stratigraphy|mountain-building|" AnswerCount="2" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="24944" PostTypeId="1" CreationDate="2023-02-22T22:45:32.943" Score="1" ViewCount="91" Body="&lt;p&gt;Simply as the title states, how did we find out about the relationship between the temperature of the air and the distance from the ground?&lt;/p&gt;&#xA;&lt;p&gt;I tried googling, but found nothing. I searched for &amp;quot;how did we find out about the relationship between the temperature of the air and the distance from the ground?&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="28543" LastEditorUserId="2470" LastEditDate="2023-02-23T01:05:36.933" LastActivityDate="2023-07-23T17:06:45.883" Title="How did we find out about the relationship between the temperature of the air and the distance from the ground?" Tags="|meteorology|" AnswerCount="1" CommentCount="3" ClosedDate="2023-07-23T20:49:12.320" ContentLicense="CC BY-SA 4.0" />
  <row Id="24946" PostTypeId="2" ParentId="24943" CreationDate="2023-02-23T00:47:35.863" Score="9" Body="&lt;p&gt;What you see are bedding surfaces. They formed horizontally in a sedimentary lacustrine environment, the Kailash Formation.&lt;/p&gt;&#xA;&lt;p&gt;This is a reconstruction of the paleoenvironment:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/QFejv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/QFejv.png&quot; alt=&quot;Enter image description here&quot; /&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;(&lt;a href=&quot;https://thewire.in/the-sciences/is-mt-kailash-the-oldest-mountain-in-the-himalaya&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;As Gimelist noted, the sedimentary layers formed above a magmatic body.&lt;/p&gt;&#xA;&lt;p&gt;The question is why they reached an altitude of 8,000 meters and are still horizontal.&lt;/p&gt;&#xA;&lt;p&gt;It is an extreme example of &lt;a href=&quot;https://en.wikipedia.org/wiki/Principle_of_original_horizontality&quot; rel=&quot;nofollow noreferrer&quot;&gt;the principle of original horizontality&lt;/a&gt;, which gives the polarity of succession. The materials above are newer than those below because they were deposited horizontally. The tectonic uplift didn't change the original horizontal arrangement.&lt;/p&gt;&#xA;" OwnerDisplayName="user28185" LastEditorDisplayName="user28185" LastEditDate="2023-03-11T16:30:21.963" LastActivityDate="2023-03-11T16:30:21.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24947" PostTypeId="2" ParentId="24942" CreationDate="2023-02-23T01:18:44.823" Score="4" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Shocked_quartz&quot; rel=&quot;nofollow noreferrer&quot;&gt;Shocked quartz&lt;/a&gt; has been found at underground nuclear test sites and major meteor impact sites. It is formed when quartz is subject to intense pressure causing to deform internally along crystal planes. When viewed under a microscopes the planes appear as lines.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Shocked quartz is found worldwide, and occurs in the thin Cretaceous–Paleogene boundary layer, which occurs at the contact between Cretaceous and Paleogene rocks. This is further evidence (in addition to iridium enrichment) that the transition between the two geologic periods was caused by a large impact.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-02-23T01:18:44.823" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24948" PostTypeId="2" ParentId="24942" CreationDate="2023-02-23T08:24:31.043" Score="4" Body="&lt;p&gt;Was it &lt;a href=&quot;https://en.wikipedia.org/wiki/Impactite&quot; rel=&quot;nofollow noreferrer&quot;&gt;impactite&lt;/a&gt;? It is the name of rocks (not metal) that have been transformed by a meteorite impact. They contain evidence for high pressures (quartz transformed into coesite, its high pressure polymorph) and high temperatures (impact melts, &lt;a href=&quot;https://en.wikipedia.org/wiki/Tektite&quot; rel=&quot;nofollow noreferrer&quot;&gt;tektites&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;Alternatively, you could have heard about the &lt;a href=&quot;https://en.wikipedia.org/wiki/Iridium_anomaly&quot; rel=&quot;nofollow noreferrer&quot;&gt;iridium anomaly&lt;/a&gt;, an iridium-rich layer associated with the Chicxulub impact. Iridium is indeed a metal. But I don't think that iridium has ever been found in craters left by nuclear explosions.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2023-02-23T08:24:31.043" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24949" PostTypeId="2" ParentId="24944" CreationDate="2023-02-23T15:22:27.840" Score="0" Body="&lt;p&gt;I think this kind of measurement became available with the use of radiosondes. For example it says on (&lt;a href=&quot;https://en.wikipedia.org/wiki/Radiosonde&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia&lt;/a&gt;) that&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Gustave Hermite and Georges Besançon, from France, were the first in 1892 to use a balloon to fly the meteograph. In 1898, Léon Teisserenc de Bort organized at the Observatoire de Météorologie Dynamique de Trappes the first regular daily use of these balloons. Data from these launches showed that the temperature lowered with height up to a certain altitude, which varied with the season, and then stabilized above this altitude.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;If you are referring to the theoretical understanding of which, the derivation of the vertical temperature profile of the atmosphere requires knowledge about the ideal gas law, which was&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;first stated by Benoît Paul Émile Clapeyron in 1834&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;says &lt;a href=&quot;https://en.wikipedia.org/wiki/Ideal_gas_law&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28529" LastActivityDate="2023-02-23T15:22:27.840" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24950" PostTypeId="2" ParentId="24907" CreationDate="2023-02-23T18:36:06.663" Score="1" Body="&lt;p&gt;The one source I can think of that's outstanding with meeting all your enumerated criteria is the following: &lt;a href=&quot;https://www.iris.edu/hq/&quot; rel=&quot;nofollow noreferrer&quot;&gt;IRIS&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;You need to research throughout that website, but they certainly have more than what you seek&lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2023-02-23T18:36:06.663" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24951" PostTypeId="1" CreationDate="2023-02-23T20:39:37.100" Score="2" ViewCount="741" Body="&lt;p&gt;A Creationists keeps responding to me insisting that radioactive dating is invalid because someone dated a 1986 lava flow from St Helens to 250,000 yrs, and they got a C14 date on Triassic Coal from the Sydney basin to 33,000 years.&lt;/p&gt;&#xA;&lt;p&gt;I have tried to explain how these results likely came about, but of course I have no idea what methods these Creationists use.&lt;/p&gt;&#xA;&lt;p&gt;see discussion here: &lt;a href=&quot;https://qr.ae/pr90Bs&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://qr.ae/pr90Bs&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The &amp;quot;gotcha&amp;quot; with the C14 is described here: &lt;a href=&quot;https://answersingenesis.org/fossils/dating-dilemma-fossil-wood-in-ancient-sandstone/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://answersingenesis.org/fossils/dating-dilemma-fossil-wood-in-ancient-sandstone/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Does anyone know more about what these idiots are up to, and able to give a better response to explain that these results are not scientific proof of anything except the inability of Creationists to apply correct methods.&lt;/p&gt;&#xA;&lt;p&gt;I see the cleverness of the 'Gotcha', it takes advantage of notions of simplistic understanding of science. Trying to explain to lay-persons the intricacies of these methods is difficult, and I am out of date myself with my geology!&lt;/p&gt;&#xA;" OwnerUserId="28550" LastActivityDate="2024-04-06T21:17:28.527" Title="Does anyone know more about Creationist stunts where they get labs to date Triassic Coal with C14 and recent Mt St Helens lava with K-Ar" Tags="|dating|radioactivity|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24952" PostTypeId="2" ParentId="24951" CreationDate="2023-02-23T22:36:21.443" Score="2" Body="&lt;p&gt;There are a number of issues associated with carbon 14 dating. Two key issues:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Carbon-14 cannot be used to date anything older than about 50 thousand years old. Carbon-14 has a half-life of about 5730 years. This short half-life is very useful for dating objects 20 thousand years old, or younger. Trying to use carbon-14 dating to date oil or coal? Useless. Trying to use carbon-14 dating on an object by other reliable estimates expected to be 225 million years old? Useless.&lt;/li&gt;&#xA;&lt;li&gt;Samples can be contaminated, either in situ, in the collection process, or in the lab. This is particularly problematic with presumably old samples. Trying to use carbon-14 dating on a sample suspected to be 225 million years old cannot say the object is 225 million years old. It might however say the object is 33 thousand years old. The sample in question was in an easily contaminated sandstone deposit. It was beyond stupid to send that sample for carbon-14 dating.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Young earth creationists know these points and know they are lying, but that doesn't stop them from doing so. Their religion is at stake.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2023-02-24T02:11:29.507" LastActivityDate="2023-02-24T02:11:29.507" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24954" PostTypeId="1" AcceptedAnswerId="24956" CreationDate="2023-02-24T07:41:49.463" Score="4" ViewCount="94" Body="&lt;p&gt;It’s common knowledge (and I’m expecting correct) that coastal regions experience moderate climate. But how far is the coastal region affected?&lt;/p&gt;&#xA;&lt;p&gt;Does this affect people sitting on the beach? The buildings facing the water on the first street? A whole city? 50km inland? An island is completely included?&lt;/p&gt;&#xA;" OwnerUserId="10789" LastActivityDate="2023-03-07T17:48:08.990" Title="“Coastal regions experience moderate climate”. What size are these regions?" Tags="|climate|water|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24955" PostTypeId="2" ParentId="24943" CreationDate="2023-02-24T12:32:49.427" Score="5" Body="&lt;p&gt;Just to add on this point from the comments:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;But this mount is the only mouth with this kind of formation in local mountain range&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;First, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Kailash#/media/File:Kailash-Barkha.jpg&quot; rel=&quot;noreferrer&quot;&gt;image on the mountain's Wikipedia&lt;/a&gt; page clearly shows that the surrounding mountains also have the horizontal layers.&lt;/p&gt;&#xA;&lt;p&gt;The Wikipedia page also states that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Mount Kailash appears to be a metasedimentary roof pendant supported by a massive granite base.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The source links for that information are broken. In any case, what this means in plain language is that Earth's surface had sedimentary layers, which are very common, and magma intruded underneath it. This is also very common. For example, the Andes and Cascades mountain ranges in Western South and North America are places where this is happening these days. Over time, the mountains (Himalayas) were pushed upwards by the Indian continent collision, and the rocks eroded away such that the mountain shows the top of the granite, overlain by the bottom of the sedimentary rocks like this:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/izWmP.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/izWmP.png&quot; alt=&quot;Kailash geology&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This (paywalled) article has more information:&#xA;&lt;a href=&quot;https://doi.org/10.1046/j.1365-2451.1998.014002067.x&quot; rel=&quot;noreferrer&quot;&gt;Kailas: geology of a sacred mountain&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="725" LastActivityDate="2023-02-24T12:32:49.427" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24956" PostTypeId="2" ParentId="24954" CreationDate="2023-02-24T20:02:52.193" Score="4" Body="&lt;p&gt;Short disclamer at the beginning: This question cannot receive an absolute answer, because the answer is as heterogeneous as coastal areas are worldwide. To answer concretely, you need to focus on a concrete example. But here is a very simplified solution:&lt;/p&gt;&#xA;&lt;p&gt;First of all, the moderate climates that exist near the coast are determined by the heat capacity of the water. Simplified, this means that water absorbs a lot of heat in the warm periods and thus cools the air temperature and releases this stored heat again in the cold months!&lt;/p&gt;&#xA;&lt;p&gt;How great the influence is depends on many factors. For example, the topography. For example, if we have a mountain range near the sea, this moderate weather is hardly noticeable in the Innlad. But also winds etc. determine how much this heat absorption and heat emission of the water influences the ambient air.&lt;/p&gt;&#xA;&lt;p&gt;However:&#xA;An impressive area where a very dry area borders the ocean and thus disproves your gerneralised statement is the Namib Desert.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Dj1dT.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Dj1dT.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.pinterest.de/pin/479140847855922452/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.pinterest.de/pin/479140847855922452/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2023-03-07T17:48:08.990" LastActivityDate="2023-03-07T17:48:08.990" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24957" PostTypeId="2" ParentId="24942" CreationDate="2023-02-25T08:22:14.597" Score="3" Body="&lt;p&gt;The metallic components of meteorites are made of nickel-iron, usually taenite that has a nickel content between 20% and 65% and kamecite with between 5% and 10% nickel.&lt;/p&gt;&#xA;&lt;p&gt;There are other elements mixed in at low concentrations - notably cobalt at around 0.6% and a mixture of Platinum Group Metals at a few 10's of parts per million. (10ppm = 0.001%). Platinum Group Metals include Palladium, Iridium, Osmium, Ruthenium, Rhodium as well as Platinum.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2023-02-25T08:22:14.597" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24958" PostTypeId="1" CreationDate="2023-02-25T16:33:14.357" Score="5" ViewCount="85" Body="&lt;p&gt;I heard that some ocean oscillations act on a time scale of a millennium. Is this true, or at least argued by some oceanographers? If so, what are they and what causes them? If not, what are the largest time scale ocean oscillations&lt;/p&gt;&#xA;&lt;p&gt;Edit: After some research, I believe I may be looking for &amp;quot;Atlantic meridional overturning circulation&amp;quot; (AMOC). However, I haven't been able to understand so far if it is a true oscillation with 1000 year period. Can anyone conform if this is so? Or is it rather that it has changed over this timescale but not necessarily following an oscillation pattern?&lt;/p&gt;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="27110" LastEditorUserId="27110" LastEditDate="2023-02-26T14:56:34.760" LastActivityDate="2023-02-26T14:56:34.760" Title="Ocean oscillations with long time periods" Tags="|climate|oceanography|paleoclimatology|ocean-currents|ocean-models|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24959" PostTypeId="1" CreationDate="2023-02-25T17:30:55.770" Score="4" ViewCount="33" Body="&lt;p&gt;I am writing a paper on the role of petroleum emplacement and grain coatings in preserving porosity during burial. I can find many sources discussing grain coatings stopping cementation in sandstone, but cannot find any information whatsoever about grain coatings in carbonate strata. What causes that difference in the importance of grain coatings?&lt;/p&gt;&#xA;" OwnerUserId="28592" LastActivityDate="2023-02-25T17:30:55.770" Title="Why are grain coatings an important mechanism for preserving porosity during burial in sandstone but not in carbonate?" Tags="|geology|petrology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24961" PostTypeId="2" ParentId="24376" CreationDate="2023-02-26T13:22:23.760" Score="0" Body="&lt;p&gt;Mr. Friedman failed to consider aspects of cell respiration and loss to environment, these two factors are enough to make short term plant photosynthesis not that useful for sequestering carbon dioxide, as lots of plants release carbon during the night (cell respiration), however if you look at the long term aspects plants can use CO&lt;sub&gt;2&lt;/sub&gt; to build plant tissue, sadly though eventually the plant would die (lets use a tree as an example) and the microorganisms will turn lots of it into carbon dioxide and the rest gets buried underground to undergo the process of being turned into coal.&lt;/p&gt;&#xA;&lt;p&gt;One additional problem would be deforestation, the Amazon rain forest is losing vegetation at a rapid rate which would also release more CO&lt;sub&gt;2&lt;/sub&gt;. So with all this evidence in mind the Amazon having met all the CO&lt;sub&gt;2&lt;/sub&gt; loss requirements might actually release more CO&lt;sub&gt;2&lt;/sub&gt; than sequester. I feel like the article notes only 1 half of the &amp;quot;Gas exchange&amp;quot; process and leaves out the respiration and decomposition processes. Hopefully this answers your question.&lt;/p&gt;&#xA;" OwnerUserId="21926" LastEditorUserId="2470" LastEditDate="2023-02-27T00:57:02.320" LastActivityDate="2023-02-27T00:57:02.320" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24962" PostTypeId="1" CreationDate="2023-02-26T18:55:33.950" Score="3" ViewCount="75" Body="&lt;p&gt;The Earth axis changes tilt with a period of 41 000 years, and with an amplitude of 1.2 degrees. What does the spectrum look like? Is it a steady periodic motion, or rather some quasi-periodic phenomenon?&lt;/p&gt;&#xA;&lt;p&gt;To clarify, I want information about frequency content of plots like this one:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eeHys.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eeHys.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/User:Tfr000#/media/File:Obliquity_berger_0_to_1000000.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="601" LastEditorDisplayName="user28185" LastEditDate="2023-02-27T13:37:22.313" LastActivityDate="2023-03-01T08:33:20.440" Title="Spectrum of tilt motion of earth axis" Tags="|earth-history|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24963" PostTypeId="2" ParentId="18286" CreationDate="2023-02-26T22:57:06.643" Score="1" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zfTbz.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Click link to see image: Kepler's 3992 B.C. Calculation, from his German work, see the cover of Chronologia. 5612 (year of creation) - 1620 (date of paper cover) = 3992 B.C.&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;To obtain the source itself, look up the bigger volume: Astronomi Opera Omnia by Joannis Kepleri.&lt;/p&gt;&#xA;&lt;p&gt;As for Newton, I cannot find the source for this. However, there has already been &lt;a href=&quot;https://creation.com/isaac-newton&quot; rel=&quot;nofollow noreferrer&quot;&gt;different kind of fact checking on this&lt;/a&gt;. This is the &lt;a href=&quot;https://www.newtonproject.ox.ac.uk/view/texts/normalized/THEM00014&quot; rel=&quot;nofollow noreferrer&quot;&gt;correspondence between Thomas Burnet and Isaac Newton&lt;/a&gt; where Newton on multiple occasions denied 6 x 24-hour creation days:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;that the duration of the first and second days might be “as long as you please”&lt;/li&gt;&#xA;&lt;li&gt;“a year for each days work”&#xA;Just to name a couple.&#xA;Therefore, if Newton had dated the creation to some young Earth 4000BC point in time, I could only assume he's either being inconsistent or the number he was doing was not meant to be treated as true creation date of the known universe but a direct assumption of 24 hour day universal definition as well as literal father-son definition (with the understanding that both of which can easily be refuted as absolute by any reasonable man) approach to Biblical calculation of the date with emphasis on &amp;quot;give or take&amp;quot; an x period of time you wish to put in should more information be made available.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;So while Kepler could be Young Earth, Newton was hardly one.&lt;/p&gt;&#xA;&lt;p&gt;Disclaimer, I'm not a Young Earth Creationist. Although, to understand Young Earth influence, I believe you must start with James Ussher and the now unpopular &lt;a href=&quot;https://en.wikipedia.org/wiki/Millennial_Day_Theory#:%7E:text=The%20Millennial%20day%20theory%2C%20the,years%20of%20peace%20and%20harmony.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Millennial Day Theory&lt;/a&gt; paradigm that ruled the thinking of his sort that could be the first who promoted and insisted Young Earth theory as orthodoxy.&lt;/p&gt;&#xA;" OwnerUserId="28596" LastEditorUserId="28596" LastEditDate="2023-02-28T01:18:13.850" LastActivityDate="2023-02-28T01:18:13.850" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24964" PostTypeId="1" CreationDate="2023-02-27T05:46:15.403" Score="3" ViewCount="73" Body="&lt;p&gt;Lookin into geothermal cooling, and want to learn more about how temperature behaves at different depths, not too deep like 100 meters or so, ignoring unusual stuff like geysers and things.&#xA;I want to know at what depth does it stabilize to the MAT(mean annual temp) and how much does it generally increase every few meters from there. Also what should i search for to find a graph that displays this?&lt;/p&gt;&#xA;" OwnerUserId="28598" LastEditorUserId="28598" LastEditDate="2023-02-27T05:53:26.623" LastActivityDate="2023-02-27T05:53:26.623" Title="At what depth does the ground stop getting cooler/hotter(summer/winter) and it starts to warm up?Where is the MAT depth or geothermal crossover?" Tags="|geology|temperature|geothermal-heat|underground-water|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="24965" PostTypeId="1" AcceptedAnswerId="24970" CreationDate="2023-02-27T20:57:21.037" Score="2" ViewCount="47" Body="&lt;p&gt;I'm trying to recreate the graphs in Figure 6.2 from this &lt;a href=&quot;https://ocw.hokudai.ac.jp/wp-content/uploads/2016/03/DynamicsOfIce-2010-Note-all.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt; (page 88). They get these plots by using the following solutions for velocity and temperature (both obtained from solving the basic parallel sided slab on slope problem).&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$v_x = \frac{2 A (\rho g sin(\alpha))^{n}}{n+1}(H^{n+1} -(H-z)^{n+1})$&lt;/span&gt;&lt;br /&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$T = T_s + \frac{q^{\perp}_{geo}}{\kappa}(H-z)+\frac{2AH^{n+3} (\rho g sin(\alpha))^{n+1}}{\kappa (n+2)} [1-\frac{z}{H} -\frac{1}{n+3}(\frac{H-z}{H})^{n+3}]$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;They say that in order to create Figure 6.2, they use the following values.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$H = 100m$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$\alpha = 10^{\circ}$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$T_s = -10^{\circ}C$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$q^{\perp}_{geo} = 50 W m^{-2}$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$n = 3$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$A = 10^{-16}a^{-1}Pa^{-3} = 10^{-16}a^{-1}kg^{-3} m^{3} s^{6}$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$\rho = 910 kg m^{-3}$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$\kappa = 2.1 W m^{-1} K^{-1} = 2.1 \mbox{kg }  \mbox{ m} \mbox{ s}^{-3}K^{-1}$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$g = 9.81 m s^{-2}$&lt;/span&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I noticed that when I plug these values into the above equations I don't get the same results as in the figure. I've seen other sources with similar graphs, for example Figure 2 showing &lt;span class=&quot;math-container&quot;&gt;$v_x$&lt;/span&gt;&lt;a href=&quot;https://glaciers.gi.alaska.edu/sites/default/files/Notes_icesheetmod_Bueler2014.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, so I know what they did is correct and I feel like I'm missing something.&lt;/p&gt;&#xA;&lt;p&gt;I checked the units carefully and they line up correctly for the &lt;span class=&quot;math-container&quot;&gt;$v_x$&lt;/span&gt; equation. For the &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; equation I noticed that I need to convert &lt;span class=&quot;math-container&quot;&gt;$T_s$&lt;/span&gt; to Kelvin first (ie add 273) before plugging into the equation, and then I needed to convert the final result of that &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; equation back to Celsius (ie by subtracting 273). This still does not give me a matching graph to what is provided in Figure 6.2.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Why aren't these figures matching when I plug the values into the equations? I've been through the math and coding a bunch and they look ok so I feel like my problem is stemming from a misunderstanding of glacier dynamics. Is there some trick that I'm missing? Thanks!&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here is the original Figure 6.2&#xA;&lt;a href=&quot;https://i.stack.imgur.com/NNHTp.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NNHTp.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here is what I got&#xA;&lt;a href=&quot;https://i.stack.imgur.com/HO8jG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HO8jG.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here is the Matlab code I used to get my results in case that helps.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;H=100;&#xA;alpha = 10;&#xA;A = 10e-16;&#xA;rho = 910;&#xA;g = 9.81;&#xA;kappa = 2.1;&#xA;n = 3;&#xA;q_geo  = 50;&#xA;Ts = -10;&#xA;&#xA;figure()&#xA;z_grid1 = linspace(0,100,401);&#xA;v_x = (2.*A.*(1/(n+1)).*(rho.*g.*sin(alpha)).^n)*(H^(n+1) -(H-z_grid1).^(n+1)); %equation 6.13&#xA;plot(v_x,z_grid1)&#xA;title('v_x graph')&#xA;xlabel('velocity [m/a]')&#xA;ylabel('Height above the base z [m]')&#xA;&#xA;&#xA;&#xA;figure()&#xA;z_grid2 = linspace(0,100,401);&#xA;T = (Ts+273) + (q_geo./kappa).*(H-z_grid2)+(2.*A.*H.^(n+3)).* (((rho.*g.*sin(alpha))^(n+1))./ (kappa.*(n+2))).*(1-(z_grid2 ./H) - (1/(n+3)).*((H-z_grid2)./H).^(n+3)); %equation 6.28&#xA;plot(T-273,z_grid2)&#xA;title('T graph')&#xA;xlabel('T [Degrees Celcius]')&#xA;ylabel('Height above the base z [m]')&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="28536" LastEditorUserId="18081" LastEditDate="2023-02-28T15:57:11.000" LastActivityDate="2023-02-28T15:57:37.677" Title="Understanding Graphs for Velocity and Temperature Solutions for Parallel Sided Slab on Slope Problem" Tags="|glaciology|numerical-modelling|matlab|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24966" PostTypeId="1" AcceptedAnswerId="24979" CreationDate="2023-02-27T22:31:11.743" Score="4" ViewCount="58" Body="&lt;p&gt;Is it possible to come up with a formula to estimate the height of the tropopause and the upper layer lapse rate only based on atmospheric composition and other atmospheric parameters (not relying on atmospheric sounding data)?&lt;/p&gt;&#xA;" OwnerUserId="28351" LastActivityDate="2023-03-01T14:37:17.160" Title="How to estimate altitude of tropopause of other planets?" Tags="|atmosphere|planetary-science|atmosphere-modelling|inversion|stratosphere|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24967" PostTypeId="1" CreationDate="2023-02-28T02:34:25.080" Score="5" ViewCount="51" Body="&lt;p&gt;I was exploring some islands by boat recently and I came upon some pretty impressive rock formation. I'm interested in finding what mechanism produces those angle mineral strips. Some of them were a couple inches wide, others some feet wide. They were angled at around 45 degrees creating lines all across the side of the island. (Which was 25 to 30m high) &lt;a href=&quot;https://i.stack.imgur.com/LsHMw.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LsHMw.jpg&quot; alt=&quot;The strip on the left of the image&quot; /&gt;&lt;/a&gt; I tried doing a research on Google but being unfamiliar with the terms of geology, I couldn't orient my search properly. Does anybody could point me to some articles or terms to help me research the subject or provide a quick explanation as to what causes those minerals to be aligned at those angles?&lt;a href=&quot;https://i.stack.imgur.com/0WAPb.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0WAPb.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The pictures aren't the best but you can see on the left of the first one the mineral strip and a smaller one on the second picture.&lt;/p&gt;&#xA;&lt;p&gt;Thanks in advance!&lt;/p&gt;&#xA;" OwnerUserId="28604" LastActivityDate="2023-02-28T02:34:25.080" Title="What explains the angled stripes of mineral visible on the side of some islands?" Tags="|geology|mineralogy|minerals|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24968" PostTypeId="1" CreationDate="2023-02-28T04:40:57.837" Score="2" ViewCount="43" Body="&lt;p&gt;I'm working through problems in the Vallis 'big book' and I'm stuck on the following problem:&lt;/p&gt;&#xA;&lt;p&gt;Consider a wind stress imposed by a mesoscale cyclonic storm (in the atmosphere) given by&lt;/p&gt;&#xA;&lt;p&gt;τ = −Aexp{−(r/λ)^2} (yi −xj)&lt;/p&gt;&#xA;&lt;p&gt;where r2 = x2 + y2, and A and λ are constants. Also assume constant Coriolis gradient β = ∂f/∂y and constant ocean depth H. In the ocean, find (a) the Ekman transport, (b) the vertical velocity wE(x, y, z)below the Ekman layer, (c) the northward velocity v(x, y, z)below the Ekman layer and (d) indicate how you would find the westward velocity u(x, y, z)below the Ekman layer.&lt;/p&gt;&#xA;&lt;p&gt;I have separated the equation into the x and y components. The transport in the U and V directions should be τ(y)/pf and -τ(x)/pf, respectively (though does this assume a f-plane?). But the vertical velocity gets very messy, and I can't seem to simplify it.&lt;/p&gt;&#xA;" OwnerUserId="28605" LastActivityDate="2023-02-28T04:40:57.837" Title="Calculating Ekman transport and vertical velocity from wind stress τ of mesoscale cyclone" Tags="|fluid-dynamics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24969" PostTypeId="1" CreationDate="2023-02-28T06:51:07.283" Score="2" ViewCount="23" Body="&lt;p&gt;I want to conduct a statistical analysis of high-frequency wind measurements. This analysis aims to define relevant parameters for competitive coastal sailboat racing so the sampling frequency should be exceptionally high (in the order of 1-0.2 Hz). Could someone please help me find such a dataset open to the public?&lt;/p&gt;&#xA;" OwnerUserId="20249" LastEditorUserId="2470" LastEditDate="2023-02-28T08:53:54.610" LastActivityDate="2023-02-28T12:26:48.310" Title="Is there an open high frequency (1-0.2 Hz) wind measurement dataset from a marine station?" Tags="|meteorology|wind|open-data|database|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24970" PostTypeId="2" ParentId="24965" CreationDate="2023-02-28T09:12:27.420" Score="2" Body="&lt;p&gt;In Matlab, trigonometry functions work with angles in radians, see for example the &lt;a href=&quot;https://www.mathworks.com/help/matlab/ref/sin.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;description&lt;/a&gt; of the &lt;code&gt;sin&lt;/code&gt; function:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Input angle in radians, specified as a scalar, vector, matrix, or&#xA;multidimensional array.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So either you keep your code but convert your 10° angle in radians (change to &lt;code&gt;alpha = 0.174533&lt;/code&gt;), or you can use the &lt;code&gt;sind&lt;/code&gt; function, which also calculates the sine but takes angles &lt;a href=&quot;https://www.mathworks.com/help/matlab/ref/sind.html#btg_ljb-3&quot; rel=&quot;nofollow noreferrer&quot;&gt;in degrees&lt;/a&gt; as input.&lt;/p&gt;&#xA;&lt;p&gt;Then, you also have a factor of 10 error in your definition of &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt;: &lt;span class=&quot;math-container&quot;&gt;$10^{-16}$&lt;/span&gt; should be noted &lt;code&gt;1e-16&lt;/code&gt;. That fixes the first graph (velocity profile):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pJdLH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pJdLH.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The second still looks weird... You also have an error in the definition of &lt;span class=&quot;math-container&quot;&gt;$q^{\perp}_{geo}$&lt;/span&gt;: the unit is mW, so it should be converted to &lt;code&gt;q_geo=0.05;&lt;/code&gt;. This fixes the first line of the equation: if you put the rest in comment, it reproduces well the linear, dashed line, up to a temperature of -7.619°C for &lt;span class=&quot;math-container&quot;&gt;$z$&lt;/span&gt; = 0 m. So the issue must be in the second part, although I cannot figure out where.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2023-02-28T15:57:37.677" LastActivityDate="2023-02-28T15:57:37.677" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24971" PostTypeId="2" ParentId="24969" CreationDate="2023-02-28T12:26:48.310" Score="2" Body="&lt;p&gt;One possible source could be the FINO stations in the North and Baltic Sea. I am not sure on how high the frequency is (couldn't find any information on the website). But I am quite sure that ultra sonic anemometers are used so the measurement frequency should be good enough for you.&lt;/p&gt;&#xA;&lt;p&gt;I suppose you have to register for the data, but I think it is free to use.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.fino-offshore.de/en/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.fino-offshore.de/en/index.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26870" LastActivityDate="2023-02-28T12:26:48.310" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24972" PostTypeId="2" ParentId="9337" CreationDate="2023-02-28T15:48:02.843" Score="3" Body="&lt;p&gt;Although most thunderstorms produce rain, most rain does not have associated lightning, so one should expect that there are places with rain and snow but little lightning and thunder.&lt;/p&gt;&#xA;&lt;p&gt;From an eyeball comparison of worldwide &lt;a href=&quot;https://doi.org/10.5194/essd-14-5665-2022&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;World Wide Lightning Location Network (WWLLN) Global Lightning Climatology (WGLC) and time series, 2022 update,  Jed O. Kaplan and Katie Hong-Kiu Lau, Earth Syst. Sci. Data, 14, 5665–5670, 2022&quot;&gt;lightning strikes&lt;/a&gt; and &lt;a href=&quot;https://earthobservatory.nasa.gov/global-maps/GPM_3IMERGM&quot; rel=&quot;nofollow noreferrer&quot;&gt;precipitation&lt;/a&gt; maps, it looks like coastal Alaska and northern British Columbia, southern Chile and most of the Southern Ocean between 45°S and 60°S (e.g. the &lt;a href=&quot;https://en.wikipedia.org/wiki/Kerguelen_Islands&quot; rel=&quot;nofollow noreferrer&quot;&gt;Kerguelen Islands&lt;/a&gt;) are the places with the most lightning-free precipitation, with coastal northwest Europe not far behind.&#xA;Pretty much any place in on a west coast at latitudes between 45° and 60° North or South will have lots of precipitation but little lightning. The prevailing westerlies off the ocean bring frequent precipitation, but the surface rarely gets hot enough to generate classic &lt;a href=&quot;https://en.wikipedia.org/wiki/Thunderstorm&quot; rel=&quot;nofollow noreferrer&quot;&gt;thunderstorms&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The Arctic and Antarctic have even less lightning but also little precipitation. Polar lightning strikes have &lt;a href=&quot;https://doi.org/10.1029/2020GL091366&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;Lightning in the Arctic, R. H. Holzworth, et al. (2021).  Geophysical Research Letters, 48, e2020GL091366&quot;&gt;recently been increasing&lt;/a&gt;, however, probably due to increased temperatures from the &lt;a href=&quot;https://en.wikipedia.org/wiki/Polar_amplification&quot; rel=&quot;nofollow noreferrer&quot;&gt;polar amplification&lt;/a&gt; of global warming.&lt;/p&gt;&#xA;" OwnerUserId="27775" LastEditorUserId="27775" LastEditDate="2023-02-28T19:12:02.207" LastActivityDate="2023-02-28T19:12:02.207" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24973" PostTypeId="2" ParentId="22600" CreationDate="2023-02-28T16:11:50.790" Score="0" Body="&lt;p&gt;Even though the Earth is mostly a solid you can treat like a viscous fluid as far as pressure calculation are performed.  When you are the surface of the earth there is the weight of 14.7 pounds of air molecules above you per square inch which is 1 ATM (101 325 Pa) of pressure at sea level.  The Earth is composed of various materials with rock at the surface and iron at the core with ever denser materials closer to the core.&lt;/p&gt;&#xA;&lt;p&gt;Metals like iron are also denser at the Earth's core due to immense pressure near the Earth's core.  Solid metals like iron will compress by 60 to 80 percent denser due to increased pressure as compared to the density at the surface of the Earth.&lt;/p&gt;&#xA;&lt;p&gt;At the center of the Earth the contributed gravitational field from the materials of the Earth would be near zero and any gravitational field felt would be from the Earth's moon.  The pressure derived at the center of the Earth is the integration or summation of gravitational weight of all the material from the center to the Earth's to the surface 4000 miles (6436 km) above. It is true that the weight of the materials near the center of the of Earth nears zero but there also much less material to integrate as compared to materials near closer to the Earth surface. Imagine a cone of material with the cone's vertex at the center and the earth and the base portion at the surface of the earth.&lt;/p&gt;&#xA;&lt;p&gt;Material farthest away from the Earth center contributes more material with proportional more gravitational force since it's farther from the center of the earth. Pressure is derived from what's above and not below as referenced from the earth's center pointing outward to the earth's surface.&lt;/p&gt;&#xA;" OwnerUserId="28608" LastEditorUserId="2470" LastEditDate="2023-02-28T18:26:07.970" LastActivityDate="2023-02-28T18:26:07.970" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24974" PostTypeId="1" CreationDate="2023-02-28T21:44:27.777" Score="1" ViewCount="414" Body="&lt;p&gt;apologies if this is the wrong place to post this question in, but I am having a really hard time grasping Coriolis Effect.&lt;/p&gt;&#xA;&lt;p&gt;My current understanding is that -&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HmisG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HmisG.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Let's say there's a point midway from Equator and North Pole. This point has a low pressure, and the areas near North Pole and Equator have high pressure.&lt;/p&gt;&#xA;&lt;p&gt;Areas away from the equator move slower, compared to the areas close to equator. Therefore, a wind flowing up will deflect to the left to meet the low pressure region, similarly, a wind flowing from North Pole to the point will deflect right since the point is moving faster than the pole.&lt;/p&gt;&#xA;&lt;p&gt;But, at the same time, I ended up with this counter argument, winds close to Equator will have a higher velocity component along the West to East direction, so when they flow up, they get deflected to right, and similarly, winds in North Pole having a low velocity component along West to East will deflect to left.&lt;/p&gt;&#xA;&lt;p&gt;Now, I am very unsure what is the flaw in my logic.&lt;/p&gt;&#xA;&lt;p&gt;Any help would be appreciated! Thank you!&lt;/p&gt;&#xA;" OwnerUserId="28601" LastActivityDate="2023-04-08T01:47:01.193" Title="Why does air moving from Equator to Poles deflect to right in Northern Hemisphere due to Coriolis Force?" Tags="|wind|tropical-cyclone|coriolis|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24975" PostTypeId="1" CreationDate="2023-03-01T02:07:41.650" Score="1" ViewCount="123" Body="&lt;p&gt;I would like to calculate dew point values at different pressure levels from the ERA5 data set. Is this possible and if so, how exactly can it be done? I have found an approximate formula that use temperature and relative humidity, but is this going to be scientifically sound? The formula is: Tdew = (237.3&lt;em&gt;X)/(17.269-X), where X=ln(Rh/100)+((17.269&lt;/em&gt;Tair)/(237.3+Tair)).&lt;/p&gt;&#xA;" OwnerUserId="28612" LastActivityDate="2023-03-01T02:07:41.650" Title="Is it possible to calculate dew point at pressure levels from ERA5 data?" Tags="|meteorology|atmosphere|reanalysis|era|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24976" PostTypeId="2" ParentId="24962" CreationDate="2023-03-01T08:00:28.150" Score="1" Body="&lt;p&gt;The frequencies of orbital parameters are available directly from tables in the reference given on your wiki link&lt;/p&gt;&#xA;&lt;p&gt;See:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://journals.ametsoc.org/view/journals/atsc/35/12/1520-0469_1978_035_2362_ltvodi_2_0_co_2.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://journals.ametsoc.org/view/journals/atsc/35/12/1520-0469_1978_035_2362_ltvodi_2_0_co_2.xml&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;These values are sufficient for looking back 1-5M years&lt;/p&gt;&#xA;&lt;p&gt;It's generally a combination of dominant fixed frequencies and then split frequencies, (ie. cos(a+delta) + cos(a-delta)). And then there is a long tail of smaller amplitude frequencies&lt;/p&gt;&#xA;&lt;p&gt;Trying to go from the time domain to frequencies with things like Fourier Transform will give you artifacts (as your sampling window can't really be a multiple of all the frequencies of interest) - so avoid doing that  :)&lt;/p&gt;&#xA;&lt;p&gt;More info is available here:&#xA;&lt;a href=&quot;https://paleodyn.uni-bremen.de/gl/tmp/Orbital.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://paleodyn.uni-bremen.de/gl/tmp/Orbital.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;If you want to look further back in time, then you need to use other more advanced systems b/c it needs to account for things like the mass of icesheets (mass moving poleward) and other details. Small errors over millions of years (and thousands of cycles) will lead to large errors&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://vo.imcce.fr/insola/earth/online/earth/online/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://vo.imcce.fr/insola/earth/online/earth/online/index.php&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But at those time scales you in effect have some frequency modulation going on, and looking at the spectrum won't make much sense&lt;/p&gt;&#xA;" OwnerUserId="22874" LastEditorUserId="22874" LastEditDate="2023-03-01T08:33:20.440" LastActivityDate="2023-03-01T08:33:20.440" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24977" PostTypeId="2" ParentId="24289" CreationDate="2023-03-01T08:01:56.233" Score="1" Body="&lt;p&gt;Perhaps I am completely wrong, this is kindof a guess:&lt;/p&gt;&#xA;&lt;p&gt;Sepiolite happens in clay regions like those produced by ice age glacial activity from orogeny.&lt;/p&gt;&#xA;&lt;p&gt;If there are great lakes with high clay contents, and a specific type of volcano deposits a lot of magnesium enriched ash into the lakes, the clay and the magnesium can dissolve and precipitate into high quantites of sepiolite precursor. This then settles down to the lake bed and &lt;a href=&quot;https://www.youtube.com/watch?v=6RTRl7_Hc8k&quot; rel=&quot;nofollow noreferrer&quot;&gt;coalesces&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I may be completely wrong, here's a research article: &lt;a href=&quot;https://www.researchgate.net/publication/268577590_The_volcanic_origin_for_the_worlds_greatest_sepiolite_accumulations_Tajo_Basin_Central_Spain&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/publication/268577590_The_volcanic_origin_for_the_worlds_greatest_sepiolite_accumulations_Tajo_Basin_Central_Spain&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="3315" LastActivityDate="2023-03-01T08:01:56.233" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24978" PostTypeId="2" ParentId="24974" CreationDate="2023-03-01T14:29:17.583" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Therefore, a wind flowing up will deflect to the left to meet the low pressure region, similarly, a wind flowing from North Pole to the point will deflect right since the point is moving faster than the pole.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I'm not sure, what you mean by &amp;quot;flowing up&amp;quot;, but I'm assuming you mean &amp;quot;flowing poleward&amp;quot;. At any rate, the Coriolis force is completely independent of the pressure field - it is a purely kinematic law. The pressure difference only drives the poleward movement, which is, in turn, deflected by the Coriolis Force.&lt;/p&gt;&#xA;&lt;p&gt;To illustrate, imagine you are standing on the north pole and you throw a ball south (really hard). The ball will fly straight south whereas the earth beneath it is rotating eastward (to the &lt;strong&gt;left&lt;/strong&gt; from the north pole perspective). This means, from the earths perspective, the ball is bending to the &lt;strong&gt;right&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Similarly, If you're standing on the equator and you throw a ball northward, it has a higher eastward velocity compared to the earth's surface more northward. This means, from the ball's perspective, the earth is rotating westward, or, to the &lt;strong&gt;left&lt;/strong&gt; and from the earth's perspective, the ball is, again, deflected to the &lt;strong&gt;right&lt;/strong&gt;.&lt;/p&gt;&#xA;" OwnerUserId="28529" LastActivityDate="2023-03-01T14:29:17.583" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24979" PostTypeId="2" ParentId="24966" CreationDate="2023-03-01T14:37:17.160" Score="3" Body="&lt;p&gt;The existence, and accordingly the height, of a tropopause depends on whether the other planets' atmosphere has a layer of ozone or any other gas that absorbs some part of incoming solar radiation leading to a substantial heating and, hence, a significant temperature inversion.&lt;/p&gt;&#xA;&lt;p&gt;Given an atmospheric composition, to attain some numerical values for the tropopause height and the lapse rate probably requires modelling of radiative transfer, which is a notoriously difficult task.&lt;/p&gt;&#xA;" OwnerUserId="28529" LastActivityDate="2023-03-01T14:37:17.160" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24980" PostTypeId="1" CreationDate="2023-03-02T04:38:21.157" Score="1" ViewCount="56" Body="&lt;p&gt;Considering the amount of available energy there is for the conversion to electricity (ocean waves being endless) I would imagine more attention to this approach by all energy based-companies, as well as world powers. I have ideas about this, sorry if I am vague at the moment.  But what is hindering this relatively new technology from advancing to the point where it's a major source of power?&lt;/p&gt;&#xA;" OwnerUserId="28622" LastEditorUserId="6298" LastEditDate="2023-03-02T05:32:39.330" LastActivityDate="2023-03-03T00:44:18.433" Title="What are the inhibiting factors that are hindering ocean wave-based electricity generation?" Tags="|hydrology|waves|energy|technology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24981" PostTypeId="1" CreationDate="2023-03-02T07:00:17.087" Score="1" ViewCount="16" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/VQPBd.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VQPBd.png&quot; alt=&quot;Mixed space-time domain formulation of the energy cycle&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(Where can I know) How these formulae in the figure (Ulbrich and Speth, 1991), called mixed space-time domain formulation of the energy cycle, were deduced?&lt;/p&gt;&#xA;&lt;p&gt;And the reference Arpe et al. (1986), I can not find it on internet, could anyone find it?&lt;/p&gt;&#xA;&lt;p&gt;Arpe, K., Brancovic, C., Oriol, E., Speth, P., 1986: Variability in time and space of energetics from a long series of atmospheric data produced by ECMWF. Beitr. Phys. Atmos., 59, 321-363.&lt;/p&gt;&#xA;&lt;p&gt;U. Ulbrich and P. Speth, 1991: The global energy cycle of stationary and trasient atmospheric wave: results from ECMWF anayses. Meteorol. Atmos. Phys. 45, 125-138.&lt;/p&gt;&#xA;" OwnerUserId="28624" LastEditorUserId="28624" LastEditDate="2023-03-02T07:05:11.423" LastActivityDate="2023-03-02T07:05:11.423" Title="How to deduce the atmospheric mixed time-space domain energy cycle formulae, and where can Arpe et al. (1986) be found?" Tags="|meteorology|energy|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24982" PostTypeId="1" CreationDate="2023-03-02T09:55:42.000" Score="2" ViewCount="39" Body="&lt;p&gt;I wanted to ask if you have any suitable literature on copper slate (especially about the genesis) in the Harz Mountains. I was generally interested in how this copper shale differs from other copper shales.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="2470" LastEditDate="2023-03-02T19:49:23.400" LastActivityDate="2023-03-02T19:49:23.400" Title="Copper shale in the Harz Mountains (Germany)" Tags="|geology|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24983" PostTypeId="1" CreationDate="2023-03-02T21:38:35.487" Score="1" ViewCount="20" Body="&lt;p&gt;I'm trying to find data that I can use to compare to the graph in Figure 6.2 on page 88 of this &lt;a href=&quot;https://ocw.hokudai.ac.jp/wp-content/uploads/2016/03/DynamicsOfIce-2010-Note-all.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt; which shows temperature (found from solving the parallel sided slab on slope problem) vs height above glacier base. I found data via the NSIDC database for the temperature profile of the West Antarctic Ice Sheet Divide Deep Borehole (Version 1, NSDIC-0550). The data description says that the data reports depth vs temperatures in the fluid-filled portion of the West Antarctic Ice Sheet Divide (WAIS-D) deep borehole from December 5th 2011. The spatial coverage listed for the data is Spatial Coverage:&#xA;N: -79.4676  S: -79.4676  E: -112.0865  W: -112.0865. It looks like what I want but I don't know enough about glaciology to know for sure. I know that the full WAIS cannot be modeled as a slab on slope but I was hoping maybe this portion of it could be. Additionally, I'm concerned that these measurements were taken in the part of the borehole filled with water.&lt;/p&gt;&#xA;&lt;p&gt;Here are some links to the data that I described: &lt;a href=&quot;https://nsidc.org/data/nsidc-0550/versions/1&quot; rel=&quot;nofollow noreferrer&quot;&gt;link1&lt;/a&gt;, &lt;a href=&quot;https://www.usap-dc.org/view/dataset/609550&quot; rel=&quot;nofollow noreferrer&quot;&gt;link 2&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Are these data a good to use for comparing the graph of temperature vs depth above surface found from the slab on slope problem?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I was originally trying to find data for the Mendenhall Glacier because I read something about it being a reasonable comparison for the slab on slope problem but I haven't found the type of data I want yet. Would this be a better glacier to pursue for my purposes?&lt;/p&gt;&#xA;" OwnerUserId="28536" LastEditorUserId="28536" LastEditDate="2023-03-03T01:00:50.437" LastActivityDate="2023-03-03T01:00:50.437" Title="Is This Portion of the West Antarctic Ice Sheet Divide a Good Representation of Parallel Sided Slab on Slope Glacier" Tags="|glaciology|open-data|data-analysis|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24984" PostTypeId="2" ParentId="24980" CreationDate="2023-03-03T00:44:18.433" Score="2" Body="&lt;p&gt;Factors that inhibit the exploitation of ocean wave energy:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Only seaboard countries can have primary access to ocean waves.&lt;/li&gt;&#xA;&lt;li&gt;Some seaboard countries have long coastlines, other have short coast    lines.&lt;/li&gt;&#xA;&lt;li&gt;Sea ice in arctic countries reduces the sea space available to&#xA;utilize ocean waves.&lt;/li&gt;&#xA;&lt;li&gt;Though ocean waves are a constant, their energy intensity varies&#xA;during the course of each day. This is partly due to the affects of&#xA;wind direction and strength and ocean tides.&lt;/li&gt;&#xA;&lt;li&gt;Coastal shipping routes can affect where wave energy generators can&#xA;be located, as can the migration routes and calving regions, of certain marine species and the location of colonies of ocean going fauna, such as seals, penguins and coastal birds that rely on the ocean for their food. They must also not interfere with fisheries, spawning regions are coastal regions of marine significance, such as coral reefs.&lt;/li&gt;&#xA;&lt;li&gt;Oceans are a hostile environment. Wave generators must withstand&#xA;constant buffeting by the waves and exposure to the Sun. The water&#xA;is saline and thus corrosive. This places special requirements on&#xA;which materials can be used and also on seals and bearings for&#xA;rotating equipment and cables. Their anchors to the sea floor need&#xA;to be sturdy, but also flexible to accommodate differences in sea&#xA;level due to tides and ocean surges.&lt;/li&gt;&#xA;&lt;li&gt;Wave generators will only be able to operate in locations which do&#xA;not experience extreme waves, either very high and aggressive waves&#xA;or waves that are exceedingly gentle. This also limits where and&#xA;when they can be used. Regions that are affected by cyclones/typhoons/hurricanes or that can be affected by tsunamis can greatly affect where wave generators can be situated or how they are designed, constructed and anchored to the sea floor.&lt;/li&gt;&#xA;&lt;li&gt;One also needs to consider the amount of energy that can be utilized&#xA;from ocean waves, in a given location, compared to other sources of energy and which gives a greater economic return on each type of electricity generating system.&lt;/li&gt;&#xA;&lt;li&gt;The protection of such important national assets during times of&#xA;conflict would be an additional concern.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-03-03T00:44:18.433" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24985" PostTypeId="1" AcceptedAnswerId="25008" CreationDate="2023-03-03T12:26:36.830" Score="3" ViewCount="87" Body="&lt;p&gt;I have a sea surface temperature time series, and I want to calculate the (Pearson) correlation coefficients among the nodes in the tropics (30.0N to 30S). In the time series, the land information is present as masked. I do not know how to handle masked data in correlation calculation. Please help. The data I used here is in this link &lt;a href=&quot;https://drive.google.com/file/d/1SVKQ4uBDEZOuN7_ftd5tqpF9_NGKY3pZ/view?usp=sharing&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://drive.google.com/file/d/1SVKQ4uBDEZOuN7_ftd5tqpF9_NGKY3pZ/view?usp=sharing&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I tried the following code, which did not work:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;      temp5 = 'sst.day.mean.1983.nc'&#xA;      fh5 = Dataset(temp5, mode = 'r')&#xA;      sst5 = fh5.variables['sst'][:365]&#xA;      time = fh5.variables['time'][:]&#xA;      lat = fh5.variables['lat'][210:510][::35] #tropics latitude&#xA;      lon = fh5.variables['lon'][::45]&#xA;&#xA;      mar_05=[]&#xA;      for i in range(len(lat)):&#xA;        for j in range(len(lon)):&#xA;           for m in range(len(lat)):&#xA;              for n in range(len(lon)): &#xA;               mar_05.append(np.corrcoef(sst5[59:90,i,j],sst5[59:90, m,n][0,1]))&#xA;      df = pd.DataFrame(data = mar_05)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="28634" LastEditorUserId="2470" LastEditDate="2023-03-03T17:11:20.580" LastActivityDate="2023-03-08T16:57:37.630" Title="Correlation calculation of masked array:" Tags="|netcdf|correlation|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="24987" PostTypeId="1" CreationDate="2023-03-03T16:55:44.910" Score="1" ViewCount="29" Body="&lt;p&gt;&lt;em&gt;Bikini Atoll is at the northern end of the Ralik chain, and in a region that is somewhat drier.  On average, the Atoll receives 1300 mm of rainfall each year, with the wettest season being from May through November.  Total annual evapotranspiration is 1040 mm, with the remained being recharge.&#xA;Aquifers&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;The islands are composed of calcium carbonate sands over consolidated reef rock (calcium carbonate).&lt;br /&gt;&#xA;Look at bikini island. The sands comprise the primary aquifer on the island.  They have an average hydraulic conductivity of 5 × 10&lt;sup&gt;-3&lt;/sup&gt; cm/sec.  Sands extend to approximately 5 meters below sea level.  Porosity of the sands is 30%.  The reef rock has a lower hydraulic conductivity of 8 × 10&lt;sup&gt;-5&lt;/sup&gt; cm/sec, and can only be considered a secondary source due to unreliable yields.&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Assume the density of seawater is 1.025 g/cm&lt;sup&gt;3&lt;/sup&gt; and freshwater is 1.000 g/cm&lt;sup&gt;3&lt;/sup&gt; .&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Mission:&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;Calculate the volume of available water for Bikini Island.  You can model it as an infinite strip, but need to take care near the ends of the island.&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Use Google Earth to make measurements.&lt;/p&gt;&#xA;&lt;p&gt;I made some measurements of Bikini Island: ~3700 m long and 850 m wide. I think I'm supposed to use Darcy's Law and make multiple measurements from the center of the island but I'm not really sure what to do with that. Any pointers would help.&lt;/p&gt;&#xA;" OwnerUserId="28636" LastEditorUserId="2470" LastEditDate="2023-03-03T17:09:42.350" LastActivityDate="2023-03-03T17:09:42.350" Title="Hydrogeology Aquifer Question - Estimating Freshwater Availability" Tags="|geology|hydrology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24988" PostTypeId="1" AcceptedAnswerId="24993" CreationDate="2023-03-03T19:09:16.763" Score="5" ViewCount="1779" Body="&lt;p&gt;As sea ice is floating in oceans, it is currently occupying a volume of oceans. And also ice is less dense than water, and thus it has a greater volume with the same amount of mass compared to water. So will melting sea ice directly cause a rise in the sea level?&lt;/p&gt;&#xA;&lt;p&gt;Does melting sea ice have a &lt;strong&gt;direct&lt;/strong&gt; influence in the rise of sea level or not? There may be indirect results which are out of scope of this question.&lt;/p&gt;&#xA;" OwnerUserId="28507" LastEditorUserId="502" LastEditDate="2023-03-06T10:49:42.133" LastActivityDate="2023-03-06T16:03:15.450" Title="Does melting sea ice rise the global sea level?" Tags="|sea-level|sea-ice|" AnswerCount="4" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24989" PostTypeId="1" AcceptedAnswerId="25014" CreationDate="2023-03-03T19:21:30.967" Score="4" ViewCount="119" Body="&lt;p&gt;I have WRF data on isobaric levels that unfortunately does not contain a z-wind or omega field within the output, and I would like to produce some estimate as to the magnitude of synoptic-scale vertical motions.&lt;/p&gt;&#xA;&lt;p&gt;Upon reviewing the three main methods of estimating vertical motion in prior papers (kinematic, thermodynamic, and QG-omega), I've decided that implementing the kinematic method might be the most straightforward method to understand and also seems to be best suited to my needs. I initially tried solving for the traditional QG-Omega equation, but I am really struggling with &amp;quot;inverting&amp;quot; the laplacian on the left-hand side of the equation, and so have now opted to approach this problem using the kinematic method. However, I'm running into some trouble working out the logic of using this method in my head.&lt;/p&gt;&#xA;&lt;p&gt;Its derivation seems easy enough. Starting with the continuity equation in pressure coordinates:&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\frac{dw}{dp} + \frac{du}{dx} + \frac{dv}{dy} = 0&#xA;$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;we can rearrange and integrate to yield:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;w_{p} = w_{p+\Delta p} + \int_{p}^{p+\Delta p} ( \frac{du}{dx} + \frac{dv}{dy})dp&#xA;$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where w is vertical velocity, p is some reference pressure, u is zonal wind, and v is meridional wind.&lt;/p&gt;&#xA;&lt;p&gt;Now the problem I'm running into is that much of the literature recommends against using the kinematic method for acquiring a realistic estimate of vertical motion. This seems mainly due to the fact that the geostrophic wind is non-divergent, and errors in the ageostrophic wind are large enough to significantly affect horizontal divergence. This makes sense to me for instances where one is using observations, since the goal is to match reality as closely as possible, and observational readings are prone to error both due to instrumentation and error that likely arises from the interpolation process from discrete observations onto a grid.&lt;/p&gt;&#xA;&lt;p&gt;However, for model data, would this drawback still apply? There are no &amp;quot;errors&amp;quot; since the fields are continuous and the model is simulating everything based on its own assumptions. In that sense, I'm not looking to match reality, but rather match whatever the model's reality is. It seems to me like this is how the WRF model already calculates omega (indicated within the comments of the calc_ww_cp subroutine in the WRF code, although my Fortran is a bit too rusty to actually make sense of it). Basically, I'm looking for the most efficient way of obtaining a realistic quantity representing vertical motion within the model output.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;In that sense, is the integration of the continuity equation the best way of accomplishing this for numerical model output? Or is it worthwhile to pursue a different method?&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Thanks in advance, and I look forward to any fruitful discussions that can come out of this!&lt;/p&gt;&#xA;" OwnerUserId="28638" LastEditorUserId="28638" LastEditDate="2023-03-09T17:36:18.260" LastActivityDate="2023-03-09T17:36:18.260" Title="Estimating atmospheric vertical motion from 3D fields in WRF output" Tags="|meteorology|atmosphere|numerical-modelling|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24990" PostTypeId="2" ParentId="24988" CreationDate="2023-03-04T05:34:45.113" Score="6" Body="&lt;p&gt;The short answer is &lt;strong&gt;No&lt;/strong&gt;.&lt;/p&gt;&#xA;&lt;p&gt;If you want proof fill a glass to the brim with water. Place an ice cube in the water and wait for the ice to melt. Water will not overflow the glass.&lt;/p&gt;&#xA;&lt;p&gt;The ice that is on land, as ice sheets on Greenland and Antarctica and in glaciers and in snow caps around the world is what will cause the ocean levels to rise as they melt, as the melt water from these will be adding water to the oceans.&lt;/p&gt;&#xA;&lt;p&gt;Ice already floating on the oceans only returns to the oceans when it melts. The only reason why ice floats on water is because it is less dense than water.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-03-04T05:34:45.113" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="24991" PostTypeId="1" CreationDate="2023-03-04T13:18:06.843" Score="5" ViewCount="111" Body="&lt;p&gt;Before answering the question, keep in mind that I am a second year Biology student, with no experience in studying Physics and a very basic understanding of Mathematics. Thus, I would prefer a qualitative explanation if possible.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;I do not understand why water drifts at an angle to the wind. I understand that,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Ekman transport occurs when ocean surface waters are influenced by the&#xA;friction force acting on them via the wind. Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Ekman_transport&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I also understand that,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;As the wind blows it casts a friction force on the ocean surface that&#xA;drags the upper 10-100m of the water column with it. Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Ekman_transport&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;However, I do not understand this point,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;However, due to the influence of the Coriolis effect, the ocean water&#xA;moves at a 90° angle from the direction of the surface wind. Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Ekman_transport&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I do not understand this point, because the wind itself is also veering off to the right when travelling from the equator to the poles and vice versa. What causes the differential in 'veering' to the right or the left, between the wind and the water travelling in a Northerly or Southerly direction, if both are affected by the Coriolis effect? In other words, simply stating Coriolis effect does not explain why water drifts at an angle to the wind since they are both affected by the Coriolis effect.&lt;/p&gt;&#xA;&lt;p&gt;I know this phenomenon is explained by the Ekman spiral, which I partly understand. I understand that,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;If the ocean is divided vertically into thin layers, the magnitude of&#xA;the velocity (the speed) decreases from a maximum at the surface until&#xA;it dissipates. Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Ekman_transport&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This makes sense to me, because pressure increases with water depth, meaning more wind energy is required to move 'heavier' water.&lt;/p&gt;&#xA;&lt;p&gt;Albeit, I do not understand why,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The direction also shifts slightly across each subsequent layer (right&#xA;in the northern hemisphere and left in the southern hemisphere). Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Ekman_transport&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;My only idea is that it may have something to do with this,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The impact of the Coriolis effect is most significant with high speeds&#xA;or long distances. &lt;a href=&quot;https://education.nationalgeographic.org/resource/coriolis-effect/&quot; rel=&quot;noreferrer&quot;&gt;Source&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Explained a little bit here,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Because it largely depends on how large the difference is between an&#xA;object's velocity is and the ground's velocity, the effect is really&#xA;only significant at high speeds (either type) or long distances&#xA;(north/south especially). &lt;a href=&quot;https://stratus.ssec.wisc.edu/courses/gg101/coriolis/coriolis.html#:%7E:text=Because%20it%20largely%20depends%20on,360%20degrees%20per%20day%2C%20or%20.&quot; rel=&quot;noreferrer&quot;&gt;Source&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So the direction of water shifting slightly across each subsequent layer might have to do with the different velocities of the water layers compared to each other and the wind. Furthermore, I get why the Coriolis effect is greater over longer distances on Earth, because points on the equator are moving faster then points on the poles. However, what do these sources mean by high speeds exactly? Are they referring to the object's speed due to the Earth's rotation (pushing it in an Easterly direction) or due to the force pushing an object in a Northerly or Southerly direction for example? How do higher speeds make the Coriolis effect greater? The answers to these sub-questions will help me understand why water drifts at an angle to the wind.&lt;/p&gt;&#xA;" OwnerUserId="28640" LastActivityDate="2023-03-06T21:13:28.243" Title="How does the Coriolis effect explain Ekman transport?" Tags="|oceanography|ocean-currents|coriolis|air-currents|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="24992" PostTypeId="2" ParentId="24988" CreationDate="2023-03-04T19:23:43.423" Score="7" Body="&lt;p&gt;With two exceptions, the answer is no. Sea ice forms from seawater. Sea ice forms from early autumn to early spring but then melts from early spring to early autumn. If there is any change in volume due to sea ice being nearly pure water while seawater is salty (note well: this is very small change), it repeats.&lt;/p&gt;&#xA;&lt;p&gt;One exception is addition of ice and liquid water to the oceans from glaciers sliding into the ocean. Once that glacial ice detaches from the glacier it becomes sea ice. However, the sea level rise occurs when the glacial ice slides into the ocean and detaches from the ground, rather than later when that new sea ice melts.&lt;/p&gt;&#xA;&lt;p&gt;The other exception is that water expands when it gets warmer. Less sea ice can form as the oceans get ever warmer. It is not however the freezing and melting of sea ice that make sea levels rise. That said, the reduced amounts of sea ice is one of many signs that the oceans are warming, and those warming ocean temperatures contribute to sea level rise.&lt;/p&gt;&#xA;&lt;p&gt;Until the start of this century, thermal expansion and meltwaters appeared to be coequal in terms of causing sea level rise. Since then, meltwaters from glaciers and land-based ice sheets have been contributing considerably more to sea level rise than thermal expansion.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-03-04T19:23:43.423" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24993" PostTypeId="2" ParentId="24988" CreationDate="2023-03-04T21:11:40.273" Score="10" Body="&lt;p&gt;&amp;quot;Sea ices&amp;quot; - if referring to all kinds of ice floating in oceans - is not the same as &amp;quot;sea ice&amp;quot;; &lt;em&gt;sea ice&lt;/em&gt; is specifically referring to &lt;em&gt;seawater that has frozen&lt;/em&gt; and the total amount of water (and sea level) is not changed by it freezing or melting. So, no, it doesn't contribute to sea level rise from global warming.&lt;/p&gt;&#xA;&lt;p&gt;Other kinds of ice floating in oceans include glacial ice that breaks off the terminus of glaciers and river ice that is carried by river flows into the oceans. As these get added to the oceans they add to sea levels.&lt;/p&gt;&#xA;&lt;p&gt;This is glacial ice entering the oceans and adding it's volume to ocean volume -&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Sri2r.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Sri2r.jpg&quot; alt=&quot;glacial ice adding to sea levels&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But it is important to understand that it is change to glacier mass balance that determines if that ice going into the oceans is causing sea level rise; if the snowfall in glacier catchments is less than ice and meltwater flow into oceans then it is adding to sea levels, but if glaciers get more snowfall than that it will result in sea level fall.&lt;/p&gt;&#xA;&lt;p&gt;Currently global glacier mass balance is declining, with most glaciers in the world losing mass, ie glacier ice loss is currently adding to ocean volume and causing sea level rise.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Co6XF.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Co6XF.png&quot; alt=&quot;Glacier mass balance&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="18145" LastEditDate="2023-03-04T21:26:48.063" LastActivityDate="2023-03-04T21:26:48.063" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24994" PostTypeId="1" CreationDate="2023-03-05T01:52:52.043" Score="2" ViewCount="134" Body="&lt;p&gt;&lt;a href=&quot;https://earthscience.stackexchange.com/a/5257/239&quot;&gt;The top of a cumulonimbus cloud is usually about 40,000 feet and can reach heights of over 60,000 feet, which would be visible for a distance of 245 or 300 miles, respectively.&lt;/a&gt; from &lt;a href=&quot;https://earthscience.stackexchange.com/questions/5255&quot;&gt;How far away can you see a thunderstorm?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;My crazy cousin said that at, say, 300 miles, said NOT could see this cloud formation - maybe just the top of it - because of the earth curvature ( distance: 300 miles - curve 11.3618 miles below sight (also 59990.14 feet). I am certain that he is wrong. But it is logical and the earth curvature calculation is legitimate.&lt;/p&gt;&#xA;" OwnerUserId="28643" LastEditorUserId="239" LastEditDate="2023-03-05T11:23:55.707" LastActivityDate="2023-03-08T19:43:04.533" Title="My snarky cousin tossed a monkey into my ability to see large cloud at 300 miles HELP!" Tags="|meteorology|atmosphere|geography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24995" PostTypeId="2" ParentId="24988" CreationDate="2023-03-06T03:56:07.093" Score="0" Body="&lt;p&gt;Actually, the total amount of water does not change; it is just in different forms...&lt;/p&gt;&#xA;&lt;p&gt;The water on land came from rain which came from ocean evaporation, thus reducing the amount of water in the ocean.&lt;/p&gt;&#xA;&lt;p&gt;With glacier melting that water comes back to the ocean temporary rising the ocean level.&lt;/p&gt;&#xA;&lt;p&gt;At the same time as the global warming melts the glaciers, the same global warming also increase the evaporation of the ocean with rain falling on the land.&lt;/p&gt;&#xA;&lt;p&gt;In the end, it is a balanced system.&lt;/p&gt;&#xA;" OwnerUserId="28647" LastEditorUserId="502" LastEditDate="2023-03-06T16:03:15.450" LastActivityDate="2023-03-06T16:03:15.450" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="24996" PostTypeId="1" CreationDate="2023-03-06T04:36:12.373" Score="3" ViewCount="26" Body="&lt;p&gt;I once found an site on the internet that displayed the continents in a Google Earth type setting where you could spin, zoom and navigate around the Earth but in different geological time periods. You were essentially able to slide a time bar across and see the different continental configurations of a certain place over time. If someone is aware of this site please would you let me know. I've searched to no avail.&lt;/p&gt;&#xA;" OwnerUserId="24615" LastEditorUserId="2470" LastEditDate="2023-03-06T06:12:57.390" LastActivityDate="2023-03-06T06:12:57.390" Title="Google Earth type, online plate-techtonics demonstration over time" Tags="|geology|plate-tectonics|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24997" PostTypeId="2" ParentId="16560" CreationDate="2023-03-06T09:19:55.370" Score="1" Body="&lt;p&gt;In case you are interested in the final values or to benchmark your results, the optimum tilt for fix-mounted PV modules (OPTA) for maximum yearly yield is provided by &lt;a href=&quot;https://apps.solargis.com/prospect/map?c=23.362429,15.380859,4&amp;amp;s=44.527843,11.557617&amp;amp;m=solargis-opta&amp;amp;l=true&quot; rel=&quot;nofollow noreferrer&quot;&gt;Solargis Prospect map&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The algorithm behind is quite complex (I am not able to provide it). It not only consider the &lt;strong&gt;solar geometry&lt;/strong&gt; throughout the year at the particular location on the Earth, but also:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;time-series of global irradiation at tilted surface (GTI), calculated based on satellite data (cloud index), water vapour, and aerosol content in the atmosphere (time-series from atmospheric models)&lt;/li&gt;&#xA;&lt;li&gt;monthly average values of ground albedo&lt;/li&gt;&#xA;&lt;li&gt;local terrain horizon and properties&lt;/li&gt;&#xA;&lt;li&gt;(... maybe some more sources?)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;For such complexity, access to high resolution databases is needed and also reasonable computation power.&#xA;OPTA database is calculated in 2 arcmin (~4 km) resolution (pixel size).&lt;/p&gt;&#xA;" OwnerUserId="28538" LastActivityDate="2023-03-06T09:19:55.370" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="24999" PostTypeId="1" AcceptedAnswerId="25001" CreationDate="2023-03-06T14:24:24.833" Score="4" ViewCount="231" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/c5m4k.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/c5m4k.jpg&quot; alt=&quot;W. S. B. Paterson,The Physics of Glaciers: 3rd Edition(Pergamon, New York, 1994)&quot; /&gt;&lt;/a&gt;&#xA;I am trying to understand how the sublimation process can cause a positive mass balance in general, intuitively as highlighted in the text taken from W. S. B. Paterson,The Physics of Glaciers: 3rd Edition(Pergamon, New York, 1994).&#xA;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="28184" LastActivityDate="2023-03-06T18:24:40.667" Title="How can sublimation of glacial ice cause positive mass balance?" Tags="|glaciology|energy-balance|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25000" PostTypeId="1" AcceptedAnswerId="25007" CreationDate="2023-03-06T18:07:24.553" Score="1" ViewCount="156" Body="&lt;p&gt;I want to look at different areas of alpine glaciers and understand the position of 0 degree isotherm to do a comparative climate analysis. Given the mean annual air temperature and altitude, how do i calculate a 0-degree isotherm?&lt;/p&gt;&#xA;" OwnerUserId="28184" LastEditorUserId="81" LastEditDate="2023-03-07T09:03:28.047" LastActivityDate="2023-03-07T11:32:21.603" Title="What is 0 degree isotherm and how to calculate it?" Tags="|meteorology|glaciology|mountains|snow|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25001" PostTypeId="2" ParentId="24999" CreationDate="2023-03-06T18:24:40.667" Score="3" Body="&lt;p&gt;Strictly speaking sublimation is the phase change from solid to gas without an intermediate liquid phase. So the way the term sublimation has been used in the text is partly wrong. Ice and snow on a glacier can sublimate so that mass is lost directly to the atmosphere as water vapour.&lt;/p&gt;&#xA;&lt;p&gt;Water vapour in the atmosphere an also be deposited on the glacier as a solid in a reverse process called deposition or desublimation. This is where the text example contains an error in terminology.&lt;/p&gt;&#xA;&lt;p&gt;The term in the equation conerning phase changes from solid to gas or gas to solid is of course correct and it may be either positive or negative depending on which phase change direction dominates. As is stated losses from solid to gas is likely larger in most if not all cases.&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2023-03-06T18:24:40.667" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25002" PostTypeId="1" AcceptedAnswerId="25006" CreationDate="2023-03-06T19:28:07.837" Score="2" ViewCount="87" Body="&lt;p&gt;Aspect is based upon the direction of flowline axis of the glacier. is flowline axis same as ice flow direction?&#xA;What is aspect of a mountain (say in the tropics).&#xA;Would a glacier have aspect different from the aspect of the mountain underlying the glacier?&lt;/p&gt;&#xA;" OwnerUserId="28184" LastActivityDate="2023-03-07T09:14:48.090" Title="How to calculate main aspect of a glacier?" Tags="|glaciology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25003" PostTypeId="2" ParentId="24991" CreationDate="2023-03-06T21:13:28.243" Score="-1" Body="&lt;p&gt;I'm a student myself, but maybe this will help -&lt;/p&gt;&#xA;&lt;p&gt;Consider that surface winds, while influenced by the Coriolis force, are not necessarily blowing in the same direction that the deep ocean is flowing. Both are influenced by the Coriolis force, yes, but that doesn't mean that they're always flowing in the same direction. This 'mismatch' between the wind direction + the direction of flow in the ocean interior is a conceptually simple way to understand the Ekman transport. The winds drag along the surface of the water, but because the lower ocean is in something called 'geostrophic balance' (meaning primarily that its flow is heavily influenced by the Coriolis force) the lower ocean will drag the water to the right of the velocity because of this Coriolis influence. This leads to a net water transport to the right of the wind. On the surface, this manifests as the water moving at ~20degrees to the right of the wind, as as you move down in depth the Ekman spiral describes the changes in velocities induced by the effects of the flow in the ocean interior - until you reach the bottom of the layer influenced by wind, and you end up in the deeper ocean flow.&lt;/p&gt;&#xA;&lt;p&gt;Hope this helps!&lt;/p&gt;&#xA;" OwnerUserId="28605" LastActivityDate="2023-03-06T21:13:28.243" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25005" PostTypeId="1" AcceptedAnswerId="25020" CreationDate="2023-03-07T09:10:31.090" Score="2" ViewCount="362" Body="&lt;p&gt;Suppose I have a 60° fov camera pointed at the horizon and from that position I start climbing up in altitude. The higher I go the more of the earth curvature I will begin to notice.  Call the left most point in my field of vision on the horizon A and the right most point B, how would you calculate how many meters do A and B go below an imaginary straight line? Estimates are okay for my purpose.&lt;/p&gt;&#xA;" OwnerUserId="28653" LastActivityDate="2023-03-13T05:25:36.057" Title="Calculate how many meters does the visible horizon dip to the far sides of vision relative to a straight line" Tags="|sea-level|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25006" PostTypeId="2" ParentId="25002" CreationDate="2023-03-07T09:14:48.090" Score="4" Body="&lt;p&gt;Aspect refers to the direction in which a surface is directed. A mountain will have different aspects depending on which slope you consieder so your notion that a mountain has a single aspect is not correct. Therefore a mountain slope in the tropics would still have aspects to the north, south, east, west and so on.&lt;/p&gt;&#xA;&lt;p&gt;As for calculating the aspect of a glacier it can be a little complex. Smaller glaciers occupying a cirque or a valley will be simple to evaluate since it will be direction of the slope of the glacier, valley direction for a valley glacier. That said, it is not uncommon for a valley glacier to have several contributing cirques or side valley which by themselves will have different aspect from the main part of the glacier.&lt;/p&gt;&#xA;&lt;p&gt;When considering larger valley glaciers the valleys in which they reside can have varying directions along the glacier length so that the aspect fo the glacier varies along its length. The extreme case will be an ice cap which like a solitary mountain will have aspects varying 360 deg depending on which part of the ice cap you study. Oftan ice caps are divided into separate catechments and this aspect is given for each of the catchment rather than the ice cap as a whole.&lt;/p&gt;&#xA;&lt;p&gt;So aspect of a glacier will reflect the general flow direction of the glacier, reflecting the topography in which it is located, but it can be a very difficult parameter to evaluate for some cases.&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2023-03-07T09:14:48.090" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25007" PostTypeId="2" ParentId="25000" CreationDate="2023-03-07T11:32:21.603" Score="3" Body="&lt;p&gt;I'm not sure, whether there is more to this question, but the 0-degree isotherm is simply the set of height values for each point in the 2D domain (earth's surface) at which a value of 0 degrees is present (the 0 levelset of the three dimensional temperature field with respect to height).&lt;/p&gt;&#xA;" OwnerUserId="28529" LastActivityDate="2023-03-07T11:32:21.603" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25008" PostTypeId="2" ParentId="24985" CreationDate="2023-03-07T13:00:19.393" Score="1" Body="&lt;p&gt;I'm going to hazard a guess that you're using the &lt;a href=&quot;https://psl.noaa.gov/repository/entry/show?entryid=ca90a190-f6b1-475f-bbe0-53cb0a308520&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA OISST data&lt;/a&gt;, although I don't think that makes a difference for the answer here.&lt;/p&gt;&#xA;&lt;p&gt;Note that your loops,&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;for i in range(len(lat)):&#xA;    for j in range(len(lon)):&#xA;        for m in range(len(lat)):&#xA;            for n in range(len(lon)):&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;will just generate the indexes,&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;i = 0, ..., 8&#xA;    j = 0, ..., 31&#xA;        m = 0, ..., 8&#xA;            n = 0, ..., 31&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;When you then subset the global SST array using &lt;code&gt;sst5[59:90,i,j]&lt;/code&gt; and &lt;code&gt;sst5[59:90,m,n]&lt;/code&gt; you're not extracting data from the tropical points in your &lt;code&gt;lat&lt;/code&gt; and &lt;code&gt;lon&lt;/code&gt; variables, you're just extracting data from the corner of the full, global array, i.e., &lt;code&gt;sst5[:, 0:8, 0:31]&lt;/code&gt;. You can see this by printing out &lt;code&gt;sst5.shape&lt;/code&gt; in your loop, which will show,&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;...&#xA;(365, 720, 1440)&#xA;(365, 720, 1440)&#xA;(365, 720, 1440)&#xA;(365, 720, 1440)&#xA;...&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;This corner is in Antarctica, hence no SST data and &lt;code&gt;numpy.corrcoef&lt;/code&gt; will be seeing only missing data values and trying to divide by a zero covariance, yielding NaN values.  My Numpy issues the following warning when this happens:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;RuntimeWarning: invalid value encountered in true_divide&#xA;c /= stddev[:, None]&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;You could modify your program to subset the &lt;code&gt;sst5&lt;/code&gt; array before the loops:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;sst5_subset = sst5[59:90, 210:510:35, ::45]&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;and then refer to this array inside the loops:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;mar_05.append(np.corrcoef(sst5_subset[:,i,j],sst5_subset[:, m,n])[0,1])&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;But, personally, I would get rid of the loops and do this as a whole-array operation:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;sst_array = sst5_subset.reshape(sst5_subset.shape[0], -1).T&#xA;corr = np.ma.corrcoef(sst_array)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;A quick picture of the output for one point of interest:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/bzCFL.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bzCFL.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="106" LastEditorUserId="106" LastEditDate="2023-03-08T16:57:37.630" LastActivityDate="2023-03-08T16:57:37.630" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25010" PostTypeId="1" CreationDate="2023-03-08T18:39:57.333" Score="2" ViewCount="457" Body="&lt;p&gt;I'm no Geologist by any standard but I'm quite intrigued by what goes on below our feet.&lt;/p&gt;&#xA;&lt;p&gt;I came across this article that states there's a new or (confirmed) partially melted layer in the athenosphere (upper part of the mantle)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.eurekalert.org/news-releases/978653&quot; rel=&quot;nofollow noreferrer&quot;&gt;Scientists detect molten rock layer hidden under earth’s tectonic plates&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Does this add credence to Hapgood's disproven theory on Earth Crust Displacement? Or is the rock still too thick for plates to suddenly shift?&lt;/p&gt;&#xA;" OwnerUserId="28659" LastEditorUserId="18088" LastEditDate="2023-03-11T05:15:00.527" LastActivityDate="2024-03-14T22:57:16.490" Title="Does this support Hapgood's Earth Crust Displacement Theory?" Tags="|geology|geophysics|crust|mantle|continental-crust|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25011" PostTypeId="2" ParentId="24994" CreationDate="2023-03-08T19:43:04.533" Score="3" Body="&lt;p&gt;Your cousin isn't as crazy as you think. The calculation in the linked question assumes no intervening trees, buildings, hills, or mountains, but also assumes no atmospheric distortion and no refraction. I'll ignore those last two factors, for now.&lt;/p&gt;&#xA;&lt;p&gt;That calculation is how far away one can see the very top of a very tall cloud under those conditions. The rest of the cloud would be below the horizon. This is how even ancient people knew the Earth is spherical. A ship that sailed out from a harbor started to sink below the horizon until all that was left was the crow's nest at the tip of the mast, and then that too disappeared.&lt;/p&gt;&#xA;&lt;p&gt;When a sailing ship came into harbor, all that would have been visible at first would have been the crow's nest. This would initially would have been indistinguishable from a piece of flotsam. A similar issue arises with your faraway cloud that you can barely see the top of. Except perhaps for the fuzziness caused by atmospheric distortion, it will be nearly indistinguishable from a much closer but much lower and much smaller cloud.&lt;/p&gt;&#xA;&lt;p&gt;The one saving grace for your argument is atmospheric refraction. The Sun is still below the horizon when we see the sun rise, and it appears to remain above the horizon after it has actually set. Atmospheric refraction will typically enable you to see more of that faraway cloud than a simple straight line computation. On the other hand, atmospheric refraction might preclude you from seeing even the very top of that faraway cloud. The atmospheric refraction index is roughly proportional to pressure but inversely proportional to absolute temperature. A very high lapse rate might well cause light to bend upward rather than downward. (This is why predicting the exact time of sunrise and sunset is rather difficult, if not impossible.)&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-03-08T19:43:04.533" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25012" PostTypeId="1" CreationDate="2023-03-09T11:32:36.470" Score="1" ViewCount="29" Body="&lt;p&gt;Please how can I get landcover landuse data from landsat 4 or landsat 5.&lt;/p&gt;&#xA;&lt;p&gt;Please can anyone help me and provide me the details?&lt;/p&gt;&#xA;" OwnerUserId="28661" LastActivityDate="2023-03-09T11:32:36.470" Title="Remote sensing and GIS" Tags="|remote-sensing|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25014" PostTypeId="2" ParentId="24989" CreationDate="2023-03-09T17:36:02.120" Score="2" Body="&lt;p&gt;After a bit of digging, it seems that vertically integrating the continuity equation in pressure coordinates (shown above) is a sound approach for estimating vertical motion in numerical model output &lt;em&gt;&lt;strong&gt;at synoptic scales&lt;/strong&gt;&lt;/em&gt;. I say synoptic scales, because the hydrostatic approximation is used when converting the initial continuity equation in height coordinates to pressure coordinates. In cases, where the horizontal grid spacing is fine enough to resolve deep convection and/or sharp gradients in terrain (&amp;lt;~10km), the hydrostatic approximating is no longer valid, so you'll likely run into some problems.&lt;/p&gt;&#xA;&lt;p&gt;My model grid spacing is very fine (4 km), so I got around this by applying a running-mean smoothing filter of ~150 km in the x&amp;amp;y directions to the kinematic &lt;span class=&quot;math-container&quot;&gt;$\omega$&lt;/span&gt; field. This filtered out the small-scale noise and preserved the large-scale signal. Some initial tests using this method against reanalysis data produced acceptable results, so I'm confident that this implementation is justifiable.&lt;/p&gt;&#xA;&lt;p&gt;The major drawback of the kinematic method (errors in the ageostrophic wind propagating into estimates of &lt;span class=&quot;math-container&quot;&gt;$\omega$&lt;/span&gt;) does not apply to model data where the accuracy in horizontal wind is approximated to several orders of digits. In observational data, where this order of accuracy does not exist, it's recommended to avoid the kinematic method. In some personal tests, I found that integrating divergence on isobaric levels in reanalysis data (ERA5) successfully reproduces the &lt;span class=&quot;math-container&quot;&gt;$\omega$&lt;/span&gt; field within the reanalysis itself. Digging through the ECMWF technical notes confirms that continuity is used for their purpose of estimating &lt;span class=&quot;math-container&quot;&gt;$\omega$&lt;/span&gt; in gridded data (specifically, they refer to Simmons &amp;amp; Burridge (1980) - An Energy and Angular-Momentum Conserving Vertical Finite-Difference Scheme and Hybrid Vertical Coordinates [Specifically eqn (2.5). This is the approach ECMWF uses to solve for omega on hybrid vertical levels]).&lt;/p&gt;&#xA;&lt;p&gt;Speaking subjectively, this method seems to be the easiest to implement and the most intuitive. In instances where &lt;span class=&quot;math-container&quot;&gt;$\omega$&lt;/span&gt; is not available for your data and the phenomena you wish to study satisfies the hydrostatic approximation (such as in most GCMs or studies examining synoptic-scale features), the kinematic approach is justifiable.&lt;/p&gt;&#xA;" OwnerUserId="28638" LastActivityDate="2023-03-09T17:36:02.120" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25015" PostTypeId="1" AcceptedAnswerId="25021" CreationDate="2023-03-09T17:51:24.290" Score="6" ViewCount="97" Body="&lt;p&gt;I am trying to find articles/papers related to glacier fluctuations since LIA, how do i quickly analyze if the journal is good? Is impact factor sufficient to judge the journal quickly, if so, what should be the cut off?&#xA;Thank you.&lt;/p&gt;&#xA;" OwnerUserId="28184" LastActivityDate="2023-03-13T05:44:53.133" Title="How to judge a good journal for glaciology?" Tags="|glaciology|glaciation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25016" PostTypeId="2" ParentId="23894" CreationDate="2023-03-11T14:55:43.480" Score="1" Body="&lt;p&gt;Let's for a moment think about the troposphere consisting of stacked layers. The anvil clouds can only be found in the upper layer of the troposphere, since this is where they have to extend horizontally due to the tropopause acting as a natural barrier (see Figure 1. in Hartmann, Larson linked below). Let's assume that moisture does not penetrate the tropopause or stratosphere and that layers containing moisture fully absorb long wave radiation (this is obviously not true but it helps here to get to the point). This means that the outgoing long wave radiation from this upper layer can not be absorbed by water vapor by layers above them.&lt;/p&gt;&#xA;&lt;p&gt;Since the layer containing the anvil clouds will absorb all outgoing long wave radiation from the layers below (by our hypothesis stated above), we can conclude that this layer is the single most important layer that determines how much radiation is going to space and thus, &lt;strong&gt;cools&lt;/strong&gt; the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;This explains how an atmospheric layer can contribute to cooling but does not explain why cooling decreases with decreasing water vapor mixing ratio. The answer can be explained in terms of the atmospheric lapse rate.&#xA;The dry adiabatic lapse rate in the atmosphere is about &lt;span class=&quot;math-container&quot;&gt;$\Gamma_d = 10$&lt;/span&gt; K/km. The moist adiabatic lapse rate is about &lt;span class=&quot;math-container&quot;&gt;$\Gamma_w = 6$&lt;/span&gt; K/km. The more the water vapor mixing ratio decreases, the closer the lapse rate will be to &lt;span class=&quot;math-container&quot;&gt;$\Gamma_d$&lt;/span&gt;. And thus the upper most layer of the troposphere will be colder compared to a situation where the water vapor mixing ratio is high. A colder top layer will radiate less and therefore cooling decreases, since there is less outgoing long wave radiation.&lt;/p&gt;&#xA;&lt;p&gt;The FAT assumes that the temperature of this upper atmospheric layer is independent of surface temperature and thus, would amplify warming. What changes is the height of the upper layer - the troposphere has a larger vertical extent in a warming climate.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1029/2002GL015835&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hartmann, Larson - An important constraint on tropical cloud - climate feedback&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18833" LastEditorUserId="18833" LastEditDate="2023-03-11T15:56:04.337" LastActivityDate="2023-03-11T15:56:04.337" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25017" PostTypeId="2" ParentId="25010" CreationDate="2023-03-11T16:02:39.653" Score="3" Body="&lt;h3&gt;No&lt;/h3&gt;&#xA;&lt;p&gt;This is not evidence for anything of the sort. Just because you have an egg in your stomach after eating one, it doesn't mean you were hatched from an egg.&lt;/p&gt;&#xA;&lt;p&gt;Unlike some other pseudo-scientific ideas, Crust Displacement (in the form of &lt;a href=&quot;https://en.wikipedia.org/wiki/Cataclysmic_pole_shift_hypothesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;catastrophic polar shifts&lt;/a&gt;) is at least provably wrong.&lt;/p&gt;&#xA;&lt;p&gt;(I first encountered this idea in a work that blamed it on God, arguing that a polar shift was the cause of the Biblical Flood.)&lt;/p&gt;&#xA;&lt;p&gt;The evidence for plate tectonics is overwhelming, and rules out the possibility of catastrophic polar shifts. Also the evidence for &lt;a href=&quot;https://en.wikipedia.org/wiki/True_polar_wander&quot; rel=&quot;nofollow noreferrer&quot;&gt;any actual polar wander&lt;/a&gt; shows that is much more gradual than Hapgood puts forward.&lt;/p&gt;&#xA;&lt;p&gt;There is a long record of &lt;a href=&quot;https://en.wikipedia.org/wiki/Geomagnetic_reversal&quot; rel=&quot;nofollow noreferrer&quot;&gt;geomagnetic reversal&lt;/a&gt; in the Earth's crust. Ocean floor rocks show a pattern of north-oriented and south-oriented magnetic alignments over hundreds of millions of years.&lt;/p&gt;&#xA;&lt;p&gt;Had there been catastrophic pole shifts there would be random orientations in these rocks.&lt;/p&gt;&#xA;&lt;p&gt;When Hapgood's first anti-continental drift book was published in 1958, the publishers probably thought a foreword by Albert Einstein (who had been dead for 3 years) would give it cachet. But this foreword debunks Hapgood's central idea -- that polar ice could cause the crust to catastophically break loose from the inner Earth. Einstein pointed out that there wasn't enough ice, and pointed out Hapgood would have to explain why other imbalances  didn't cause similar shifts.&lt;/p&gt;&#xA;&lt;p&gt;About 2/3 of Earth's land mass of the Earth is in the Northern Hemisphere, and 1/3 is in the Southern Hemisphere. This is a crustal imbalance greater than any ice cap.&lt;/p&gt;&#xA;&lt;p&gt;Hapgood published a new book in 1970 where he argued the shifts were caused by some force inside the Earth.&lt;/p&gt;&#xA;&lt;p&gt;I think there are two misconceptions at work:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;People conflate Earth's magnetic poles with its rotation axis, making people think a geomagnetic reversal is a physical flip of the Earth.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;A basic inability to understand gravity. People can't get the association between South and Down out of their heads, even if they accept a round Earth.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2023-03-11T16:20:08.147" LastActivityDate="2023-03-11T16:20:08.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25018" PostTypeId="1" CreationDate="2023-03-11T19:08:12.580" Score="3" ViewCount="60" Body="&lt;p&gt;Recently I found &lt;a href=&quot;https://www.youtube.com/watch?v=svke_051zzc&quot; rel=&quot;nofollow noreferrer&quot;&gt;this tutorial video&lt;/a&gt; about Jet streaks (want to mention I'm only in second term so my knowledge is not advanced yet). Originally I was looking for the topic because of a particular exercise I have to solve but now I got stuck here:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bunqU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bunqU.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Mathematically it is clear for me that ageostrophic wind calculates according to&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\vec v_{ag} = \frac{1}{f} \cdot \vec k \times \frac{d \vec v}{d t}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;But now my problem:&lt;/p&gt;&#xA;&lt;p&gt;It is assumed that the real wind flows in x direction from W to (blue) E. Therefore, the ageostrophic wind is oriented towards north direction (green arrow). But, vectorially, this means that the geostrophic wind (red) must be directed a little to south so that read + green = blue.&lt;/p&gt;&#xA;&lt;p&gt;But isn't that in contradiction to the fact, that geostrophic wind is always oriented along contours of constant height? Especially in this image, the contour through the point of interest is the straight line from W to E and not oriented towards south.&lt;/p&gt;&#xA;&lt;p&gt;Moreover, its is shown in the video that the regions of convergence/divergence are N/S to the entrance and the opposite at the exit.&lt;/p&gt;&#xA;&lt;p&gt;I would have guessed, that region of divergence is on the entrance and convergence at the exit, because&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\vec \nabla \cdot  \vec v = \partial u/\partial x + \partial v/\partial y$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Since in the picture &lt;span class=&quot;math-container&quot;&gt;$v=0$&lt;/span&gt; everywhere, we would have&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\vec \nabla \cdot  \vec v = \partial u/\partial x $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;and this depends only on the zonal position, not on meridional.&lt;/p&gt;&#xA;&lt;p&gt;Do I maybe need to consider also w along z to calculate divergence? But we have been told, that vertical motion is neglectable.&lt;/p&gt;&#xA;&lt;p&gt;Something is weird here...what is wrong in my understanding?&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2023-03-11T20:13:50.533" LastActivityDate="2023-03-11T20:13:50.533" Title="How is Wind oriented in a Jet Streak?" Tags="|meteorology|wind|atmosphere-modelling|fluid-dynamics|jet-stream|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25019" PostTypeId="1" CreationDate="2023-03-12T11:40:34.727" Score="1" ViewCount="48" Body="&lt;p&gt;I need a (rough) functional relationship between these three quantities. My initial hypothesis is that the risk &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; (intended as the probability of a building damage), scales with the square root of the distance &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt; and increases exponentially with the magnitude &lt;span class=&quot;math-container&quot;&gt;$M$&lt;/span&gt;, but I am not sure about the correct normalization &lt;span class=&quot;math-container&quot;&gt;$k$&lt;/span&gt;.&#xA;&lt;span class=&quot;math-container&quot;&gt;$$R(r,M) \simeq k\frac{10^M}{r^2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;I need this to estimate the potential damage of an earthquake on physical infrastractures.&lt;/p&gt;&#xA;" OwnerUserId="28673" LastEditorUserId="28673" LastEditDate="2023-03-13T16:07:40.453" LastActivityDate="2023-03-13T16:07:40.453" Title="What is the relationship between earthquake risk, magnitude, and distance from the epicenter?" Tags="|geophysics|earthquakes|seismology|mathematics|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25020" PostTypeId="2" ParentId="25005" CreationDate="2023-03-12T11:57:06.070" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FeuSW.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FeuSW.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt;: Radius of the Earth&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$h$&lt;/span&gt;: Height of camera &lt;span class=&quot;math-container&quot;&gt;$C$&lt;/span&gt; from the surface&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt;: &lt;span class=&quot;math-container&quot;&gt;$\angle DAB$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$d$&lt;/span&gt;: Depth of the point &lt;span class=&quot;math-container&quot;&gt;$D$&lt;/span&gt; from line &lt;span class=&quot;math-container&quot;&gt;$EC$&lt;/span&gt; (the horizontal line at camera height) = Length&lt;span class=&quot;math-container&quot;&gt;$(ED)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;In &lt;span class=&quot;math-container&quot;&gt;$\Delta DBA$&lt;/span&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\cos t = \frac{R}{R+h}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;In &lt;span class=&quot;math-container&quot;&gt;$\Delta ECA$&lt;/span&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\cos t = \frac{R+h}{R+d}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\therefore \frac{R}{R+h}=\frac{R+h}{R+d}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$d = \frac{(R+h)^2}{R} - R = 2h + \frac{h^2}{R}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;For &lt;span class=&quot;math-container&quot;&gt;$h&amp;lt;&amp;lt;R$&lt;/span&gt;, the 2nd term is much smaller than the first, so it can be ignored.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\therefore d = 2h$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;In other words, your height above the surface of the Earth is equal to the depth of the furthest point you can see on the horizon, the said depth being measured from the plane from which your height is being measured, that is the plane tangential to the surface of the Earth at the point underneath you.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;We can reach the same answer using symmetry considerations as well.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="12269" LastEditorUserId="12269" LastEditDate="2023-03-13T05:25:36.057" LastActivityDate="2023-03-13T05:25:36.057" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25021" PostTypeId="2" ParentId="25015" CreationDate="2023-03-12T20:00:35.103" Score="3" Body="&lt;p&gt;A first approach would be to look at the reference lists of some good articles on glaciology. The reference list should contain several articles from journals that would be of relevance. As a glaciologist I would explicitly mention the following:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Journal of Glaciology&lt;/li&gt;&#xA;&lt;li&gt;Annals of Glaciology&lt;/li&gt;&#xA;&lt;li&gt;Journal of Geophysical Research&lt;/li&gt;&#xA;&lt;li&gt;The Cryosphere&lt;/li&gt;&#xA;&lt;li&gt;Geophysical Research Letters&lt;/li&gt;&#xA;&lt;li&gt;Frontiers in Earth Science&lt;/li&gt;&#xA;&lt;li&gt;Nature Geoscience&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;then there will be high profile papers in&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Nature&lt;/li&gt;&#xA;&lt;li&gt;Science&lt;/li&gt;&#xA;&lt;li&gt;Nature Communications&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;and a series of other journals such as:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Arctic, Antarctic and Alpine Research&lt;/li&gt;&#xA;&lt;li&gt;Geografiska Annaler Series A: Physical Geography&lt;/li&gt;&#xA;&lt;li&gt;Polar Research&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Then, because of the cross-disciplinary nature of glaciology, papers will appear in journals with e.g. atmospheric, biological, chemistry, engineering, physics themes.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="2470" LastEditDate="2023-03-13T05:44:53.133" LastActivityDate="2023-03-13T05:44:53.133" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25022" PostTypeId="1" AcceptedAnswerId="25032" CreationDate="2023-03-12T20:44:22.267" Score="3" ViewCount="121" Body="&lt;p&gt;When a meander of a river is completely cut off from the river, yet still contains water, it is called an oxbow lake.&lt;/p&gt;&#xA;&lt;p&gt;What if the meander is cut off only at the &amp;quot;exit&amp;quot;, but the &amp;quot;entrance&amp;quot; remains? This could be because of human intervention or potentially insufficient time for sediments to close the &amp;quot;entrance&amp;quot;. This section would be lake-like in that it has little current, yet still would be connected to the river.&lt;/p&gt;&#xA;&lt;p&gt;Is this still considered an oxbow lake, or is there a better term?&lt;/p&gt;&#xA;" OwnerUserId="28675" LastActivityDate="2023-03-15T17:05:48.300" Title="Oxbow lake, but not completely cut off from the river" Tags="|rivers|terminology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25024" PostTypeId="1" CreationDate="2023-03-13T16:13:42.810" Score="2" ViewCount="24" Body="&lt;p&gt;If I want to draw parallels between the glacier fluctuations between different glaciers, (considering similar size class, here, small) at&#xA;a) New Zealand&#xA;b) European Alps&#xA;c) Canadian Rocky Mountains&#xA;What are the factors I must definitely not miss to avoid the situation of comparing apples with oranges?&#xA;Thank you&lt;/p&gt;&#xA;" OwnerUserId="28184" LastActivityDate="2023-03-13T16:13:42.810" Title="Would it make sense to compare glacier fluctuations in New Zealand with Alps or Canadian rockies?" Tags="|glaciology|geomorphology|glaciation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25025" PostTypeId="1" AcceptedAnswerId="25027" CreationDate="2023-03-14T16:01:18.927" Score="1" ViewCount="85" Body="&lt;p&gt;North of the Eyre Highway in the South-East part of West Australia, there is a line of trees with desert on all sides. There is no visible river.&lt;/p&gt;&#xA;&lt;p&gt;Why is this the case?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/G11JK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G11JK.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earth.google.com/web/search/eyre+highway/@-31.9095029,127.16217085,32.48878858a,38404.35206843d,35y,-1.4009995h,2.93888429t,0r/data=CigiJgokCQ9xVdR63z_AEUtgEcjG6z_AGZ5dlVQ9y19AIUO2A7f8w19A&quot; rel=&quot;nofollow noreferrer&quot;&gt;-31.8985239 S, 127.135608 E&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="19151" LastEditorDisplayName="user28185" LastEditDate="2023-03-14T17:10:57.963" LastActivityDate="2023-03-14T17:56:59.603" Title="What is this line of trees visible on Google Earth?" Tags="|identification-request|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25026" PostTypeId="1" CreationDate="2023-03-14T17:47:41.207" Score="1" ViewCount="9" Body="&lt;p&gt;I am currently reading a paper which says&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The elevation ranges between 1700 and 2200 m show smaller&#xA;relative surface changes than the elevation ranges between 2200&#xA;and 3300 m. This has to be related to:&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The biggest glaciers where the surface loss on the&#xA;glacier banks for a considered elevation range can be partly&#xA;counter-balanced by the surface elevation lowering introducing an&#xA;apparent shift of the contour lines.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;What I want to understand is the &amp;quot;surface elevation lowering&amp;quot; phenomenon that the paper refers to.&lt;/p&gt;&#xA;&lt;p&gt;Ref: Gardent, Marie, et al. &amp;quot;Multitemporal glacier inventory of the French Alps from the late 1960s to the late 2000s.&amp;quot; Global and Planetary Change 120 (2014): 24-37.&lt;/p&gt;&#xA;" OwnerUserId="28184" LastActivityDate="2023-03-14T17:47:41.207" Title="More about hypsometry for large glaciers" Tags="|glaciology|geomorphology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25027" PostTypeId="2" ParentId="25025" CreationDate="2023-03-14T17:56:59.603" Score="3" Body="&lt;p&gt;These trees lie on the south-facing downward slope of an escarpment separating the Hampton Tableland (the southern part of the Nullarbor Plain) to the north from the Roe Plains to the south.&lt;/p&gt;&#xA;&lt;p&gt;As the name &amp;quot;Nullarbor Plain&amp;quot; suggests, the area is very dry, but this little amount of slope allows for a slightly wetter microclimate, just enough to grow some scrub and a few trees on the slope.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastActivityDate="2023-03-14T17:56:59.603" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25028" PostTypeId="1" AcceptedAnswerId="25031" CreationDate="2023-03-14T19:42:33.637" Score="4" ViewCount="142" Body="&lt;p&gt;The question is simple: I still have problems with atmospheric pressure coordinates:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FDpSF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FDpSF.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Given the pressure dependence in the picture, what are the velocity coordinates of an air parcel moving with &lt;span class=&quot;math-container&quot;&gt;$\vec v =(u, v=0, w=0)$&lt;/span&gt; along zonal direction in &lt;strong&gt;pressure coordinates&lt;/strong&gt;?&lt;/p&gt;&#xA;&lt;p&gt;Do I understand right, that in pressure coordinates there is no w but ω instead?&lt;/p&gt;&#xA;&lt;p&gt;I would say we have then the tuple&#xA;&lt;span class=&quot;math-container&quot;&gt;$$(u, v=0, ω)$$&lt;/span&gt;&#xA;with&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\omega = Dp/Dt = (\partial p/\partial x)_z \cdot Dx/Dt= (\partial p/\partial x)_z \cdot u$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;But I'm not sure, because it seems a bit weird that in the first system we have zero w and in the pressure system we have negative vertical &amp;quot;speed&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Although we normally consider only horizontal components u, v of wind, due to pressure coordinates we have a non zero &amp;quot;vertical&amp;quot; component (because pressure decreases as the parcel moves to the right in the example). How are pressure coordinates than easier to handle when there is an additional component &lt;span class=&quot;math-container&quot;&gt;$\omega$&lt;/span&gt; and we have three velocity components to consider instead of just two (of course I know that other equations become more simple as density vanishes...)?&lt;/p&gt;&#xA;&lt;p&gt;Do I have a mistake in my considerations?&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2023-03-14T20:03:39.777" LastActivityDate="2023-03-16T17:12:33.820" Title="Do I understand pressure coordinates in the right way?" Tags="|meteorology|atmosphere|atmosphere-modelling|pressure|coordinate-system|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25029" PostTypeId="2" ParentId="24461" CreationDate="2023-03-15T00:14:07.603" Score="2" Body="&lt;p&gt;Assuming gold, a siderophile, is more abundant in the metallic core, this gold may still be dredged to the surface.&lt;/p&gt;&#xA;&lt;p&gt;On Earth, there is more to tectonic activity than meets the eye. Hoggard et al. &lt;a href=&quot;https://doi.org/10.1038/ngeo2709&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;, with a summary in Ref. &lt;a href=&quot;https://www.geologyin.com/2016/05/map-of-flow-within-earths-mantle-finds.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;2&lt;/a&gt;, describe mixing processes in the Earth that extends throughout the mantle and into the core (Picture from [2]):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AQ0aw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AQ0aw.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;enter image description here&lt;/p&gt;&#xA;&lt;p&gt;Thus elements from the core may be brought up to the upper mantle and crust via the rising black plumes pictured above. The amount of material rising from the core in this manner is, of course, small, so only small amounts of siderophile elements such as gold emerge at the surface/crust in this way. Siderophiles that are more reactive to oxygen, such as iron, can partition directly into the mantle and thus may be convected into the crust more efficiently.&lt;/p&gt;&#xA;&lt;p&gt;Reference&lt;/p&gt;&#xA;&lt;p&gt;M.J. Hoggard et al. (2016) &amp;quot;Global dynamic topography observations reveal limited influence of large-scale mantle flow.&amp;quot; Nature Geoscience 9, 456–463. https:// doi.org/10.1038/ngeo2709&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.geologyin.com/2016/05/map-of-flow-within-earths-mantle-finds.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.geologyin.com/2016/05/map-of-flow-within-earths-mantle-finds.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="2470" LastEditDate="2023-03-15T11:16:54.973" LastActivityDate="2023-03-15T11:16:54.973" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25030" PostTypeId="2" ParentId="17455" CreationDate="2023-03-15T15:12:41.133" Score="3" Body="&lt;p&gt;It's very important to realize that Carbon-14 dating cannot be used to date anything older than 100,000 years, even with the most advanced technology we have today. The half-life is not long enough for traces (i.e. measurable amounts) to last that long. So it's a misnomer to think that Carbon-14 dating is responsible for dating rocks, fossils, etc. beyond that time frame.&lt;/p&gt;&#xA;&lt;p&gt;Instead, other radiometric methods like Potassium-Argon dating are used, which have much longer half lives. Even with these methods, however, we must remember the concept that we can't &amp;quot;measure&amp;quot; age. It's not a physical property we can observe like mass or volume. The concept behind these methods is to measure current decay rate, and work back from the present proportion of decay elements to find the assumed starting point. We do have to rely on the assumption that decay rates have been concept, that we can accurately estimate the starting element, and that it's been a closed system for the entire time.&lt;/p&gt;&#xA;&lt;p&gt;So yes, even the most &amp;quot;conclusive&amp;quot; dating methods rely on assumptions. There's no way around it. There is even good reason to reject these assumptions on occasion. For instance, Mt. Saint Helens gave us rocks with known ages because of observation, which we saw to have much larger proportions of decay elements than we typically assume, leading dating methods to date them at millions of years old when in reality they were less than 50 years old.&lt;/p&gt;&#xA;" OwnerUserId="28687" LastActivityDate="2023-03-15T15:12:41.133" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25031" PostTypeId="2" ParentId="25028" CreationDate="2023-03-15T16:40:50.250" Score="3" Body="&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;In pressure coordinates it is common to use &lt;span class=&quot;math-container&quot;&gt;$\omega$&lt;/span&gt; as the vertical velocity component instead of &lt;span class=&quot;math-container&quot;&gt;$w$&lt;/span&gt; as in cartesian coordinates.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Obtaining the velocity components in the pressure coordinate system:&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Using the material derivative we can relate the vertical velocity components and I will describe below how to do that.&lt;/p&gt;&#xA;&lt;p&gt;Start with two coordinate systems &lt;span class=&quot;math-container&quot;&gt;$(x, y, z, t)$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$(x, y, p, t)$&lt;/span&gt; with vertical coordinates &lt;span class=&quot;math-container&quot;&gt;$z = z(t, x, y, p)$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$p = p(t, x, y, z)$&lt;/span&gt;. A derivative of some variable &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; with respect to some other variable &lt;span class=&quot;math-container&quot;&gt;$c$&lt;/span&gt; (which can be &lt;span class=&quot;math-container&quot;&gt;$x$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$y$&lt;/span&gt; or &lt;span class=&quot;math-container&quot;&gt;$t$&lt;/span&gt;) in one system is related to the other as follows:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\left( \frac{\partial A}{\partial c} \right)_z = \left( \frac{\partial A}{\partial c} \right)_p + \frac{\partial A}{\partial p}\left( \frac{\partial p}{\partial c} \right)_z.&#xA;\end{equation}&lt;/span&gt;&#xA;For the vertical coordinates it holds that&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\frac{\partial A}{\partial p} =  \frac{\partial A}{\partial z} \frac{\partial z}{\partial p},&#xA;\end{equation}&lt;/span&gt;&#xA;and thus, we find&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\left( \frac{\partial A}{\partial c} \right)_z = \left( \frac{\partial A}{\partial c} \right)_p +  \frac{\partial A}{\partial z} \frac{\partial z}{\partial p}\left( \frac{\partial p}{\partial c} \right)_z.&#xA;\end{equation}&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;With this the (2D) gradient reads:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA; \nabla_z A = \nabla_p A + \frac{\partial z}{\partial p} \frac{\partial A}{\partial z}\nabla_z p.&#xA;\end{equation}&lt;/span&gt;&#xA;The time derivative is trivial as it follows from the general form above. Now we can write the material derivative in pressure coordinates as follows:&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\begin{split}&#xA;\left( \frac{\text{D}}{\text{D} t} \right)_p &amp;amp;= \left( \frac{\partial}{\partial t} \right)_p+ \vec{u} \cdot \nabla_p + \omega \frac{\partial}{\partial p}\\&#xA;&amp;amp;= \left( \frac{\partial }{\partial t} \right)_z -  \frac{\partial z}{\partial p}\left( \frac{\partial p}{\partial t} \right)_z \frac{\partial }{\partial z} + \vec{u} \cdot \left[ \nabla_z  - \frac{\partial z}{\partial p} \nabla_z p \frac{\partial }{\partial z} \right] + \omega \frac{\partial z}{\partial p}\frac{\partial}{\partial z} \\&#xA;&amp;amp;= \left( \frac{\partial }{\partial t} \right)_z + \vec{u} \cdot \nabla_z + \left[\omega - \left(\frac{\partial p}{\partial t}\right)_z - \vec{u} \cdot \nabla_z p \right] \frac{\partial z}{\partial p} \frac{\partial}{\partial z} .&#xA;\end{split}&#xA;\end{equation}&lt;/span&gt;&#xA;Hence,&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA; w = \left[\omega - \left(\frac{\partial p}{\partial t}\right)_z - \vec{u} \cdot \nabla_z p \right] \frac{\partial z}{\partial p}&#xA;\end{equation}&lt;/span&gt;&#xA;and&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\omega =\left( \frac{\partial p }{\partial t}\right)_z + \vec{u} \cdot \nabla_z p + w \frac{\partial p}{\partial z}.&#xA;\end{equation}&lt;/span&gt;&#xA;What typically follows is the use of the hydrostatic approximation in the last term. If you do a (large) scale analysis you will find that &lt;span class=&quot;math-container&quot;&gt;$-w\rho g = w \partial p/\partial z$&lt;/span&gt; is the dominating term and thus, you can approximate &lt;span class=&quot;math-container&quot;&gt;$\omega = -w\rho g$&lt;/span&gt;. However, based on your sketch I think it would not add to an understanding to just say &lt;span class=&quot;math-container&quot;&gt;$\omega = 0$&lt;/span&gt;, since &lt;span class=&quot;math-container&quot;&gt;$w = 0$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Why it makes sense to use pressure coordinates I tried to answer &lt;a href=&quot;https://earthscience.stackexchange.com/questions/19754/what-is-the-explanation-of-using-pressure-units-hpa-to-express-height-when-dea&quot;&gt;here&lt;/a&gt;, although I want to add that in a theoretical context it can be much more useful to apply e.g. sigma coordinates (terrain following coordinates) to simplify the treatment of boundary conditions.&lt;/p&gt;&#xA;" OwnerUserId="18833" LastEditorUserId="18833" LastEditDate="2023-03-16T17:12:33.820" LastActivityDate="2023-03-16T17:12:33.820" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25032" PostTypeId="2" ParentId="25022" CreationDate="2023-03-15T17:05:48.300" Score="4" Body="&lt;p&gt;I am not aware of a common unique specific name for this, but if the meander is a backwater, I believe it could still be described as an oxbow lake even if not completely cut-off from the river.  A river &lt;a href=&quot;https://en.wikipedia.org/wiki/Backwater_(river)&quot; rel=&quot;nofollow noreferrer&quot;&gt;&amp;quot;backwater&amp;quot;&lt;/a&gt; is any part of a river system where there is little or no current, and includes side channels that have no outlet. In some places it might be referred to as &lt;a href=&quot;https://en.wikipedia.org/wiki/Slough_(hydrology)#Formation&quot; rel=&quot;nofollow noreferrer&quot;&gt;&amp;quot;slough&amp;quot;&lt;/a&gt;, but again this term is more general than the exact configuration you describe.&lt;/p&gt;&#xA;&lt;p&gt;There have been some attempts in the research literature to classify oxbow lakes with different morphologies. The situation you describe - an oxbow lake with a closed downstream limb and an open upstream limb - would match 3 (depending on the curvature of the upstream connection) of the 16 oxbow classifications by &lt;a href=&quot;https://doi.org/10.1029/WR013i001p00195&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;Morphometric definitions and classifications of Oxbow Lakes, Yukon River Basin, Alaska, John G Weihaupt, 1977, Alaska, Water Resour. Res., 13( 1), 195– 196&quot;&gt;Weihaupt&lt;/a&gt; (which is unfortunately paywalled).&lt;/p&gt;&#xA;" OwnerUserId="27775" LastActivityDate="2023-03-15T17:05:48.300" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25034" PostTypeId="2" ParentId="24623" CreationDate="2023-03-16T19:08:16.817" Score="1" Body="&lt;p&gt;This pair of pictures shows that the sky is not only becoming more whitish. It also becomes more greenish.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2tb3q.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2tb3q.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;On the left is a picture of a typical winter scene. On the right a filter is added, its color and transparency adjusted to produce a neutral gray (65% black, 35% white) in the upper portion of the sky. We see the lower sky under this filtration become greenish, more brightly so as well as lighter near the horizon. Note also that to achieve the gray color at the top, the filter had to be colored orange-yellow instead of pure yellow, as seen in the car and road below; thus the complementary color of even the upper part of the sky is a slightly greenish blue.&lt;/p&gt;&#xA;&lt;p&gt;What this shows is that as we move down the sky and the scattering path becomes longer, green light is the first to become more visibly scattered (even relatively high in the sky, as noted above) because its wavelength is nearest to the violet and blue wavelengths that are strongly scattered in the whole sky. Thus the evolving color of the sky as one approaches the horizon results from both a greater amount of light scattering and the extension of our perception of this scattering into more of the visible spectrum.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2023-04-01T15:22:17.297" LastActivityDate="2023-04-01T15:22:17.297" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25035" PostTypeId="2" ParentId="7056" CreationDate="2023-03-16T20:11:41.693" Score="4" Body="&lt;p&gt;How's the weather?&lt;/p&gt;&#xA;&lt;p&gt;The circulation of winds around high and low pressure centers is driven by the &lt;a href=&quot;https://en.wikipedia.org/wiki/Coriolis_force&quot; rel=&quot;nofollow noreferrer&quot;&gt;Coriolis force&lt;/a&gt;, which occurs on rotating bodies. This of itself does not exclude a flat Earth, for the Coriolis force can occur on a rotating disc (and that model actually does account for the stability of the Lagrange-point objects in space that are now known to follow the orbits of most planets). But the Coriolis force on a rotating disc is uniform in magnitude and direction, and weather observations on Earth disagree with both claims. The apparent dependence of wind circulation on latitude and the reversal that occurs when you move from the Northern to the Southern Hemisphere are instead more consistent with a rotating sphere.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2023-08-10T16:53:12.213" LastActivityDate="2023-08-10T16:53:12.213" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25036" PostTypeId="1" AcceptedAnswerId="25037" CreationDate="2023-03-16T22:57:58.680" Score="25" ViewCount="2155" Body="&lt;p&gt;I believe the temperature gradient underground is as high as 30°C per kilometer of depth. Thus, it is very warm only 1 kilometer below the Earth's surface. Yet, it is commonly stated that geothermal energy is insignificant to the Earth's surface temperature. How can this be?&lt;/p&gt;&#xA;" OwnerUserId="27110" LastEditorUserId="6129" LastEditDate="2023-03-22T15:43:33.187" LastActivityDate="2023-03-22T15:43:33.187" Title="Why is geothermal heat insignificant to surface temperature?" Tags="|climate|temperature|geothermal-heat|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25037" PostTypeId="2" ParentId="25036" CreationDate="2023-03-16T23:48:01.503" Score="37" Body="&lt;p&gt;One kilometer of rock is actually a lot to dig through to get to that very warm condition.&lt;/p&gt;&#xA;&lt;p&gt;The key quantity here is &lt;strong&gt;heat flux.&lt;/strong&gt; The crux of the matter is:&lt;/p&gt;&#xA;&lt;p&gt;Geothermal heat flux is only a small fraction of a percent of solar heat flux.&lt;/p&gt;&#xA;&lt;p&gt;Solar heat flux balance terms are on the order of tens to hundreds of watts per square meter &lt;a href=&quot;https://www.azimuthproject.org/azimuth/show/Solar+radiation&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The earth’s surface absorbs 156 W/m² from the sun (as a global average) and emits 55 W/m² long-wave energy to the atmosphere. The atmosphere absorbs 84 W/m² and emits 185 W/m² as longwave radiation to space.&lt;/p&gt;&#xA;&lt;p&gt;The above figures are from Barry and Chorley, 2003[¹]. The account in Kiehl and Trenberth’s 1997 paper[²] is more complicated, but it can be partially summarized by this picture:&lt;/p&gt;&#xA;&lt;p&gt;In particular, note that they list:&lt;/p&gt;&#xA;&lt;p&gt;342 W/m² (341 W/m²) average power hitting the Earth’s atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;198 W/m² (184 W/m²) average power hitting the Earth’s surface.&lt;/p&gt;&#xA;&lt;p&gt;168 W/m² (161 W/m²) average power being absorbed by the Earth’s surface.&lt;/p&gt;&#xA;&lt;p&gt;Bracketed figures are from the Trenberth et al 2009 paper[³].&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In contrast, geothermal heat flux is measured in tens of &lt;em&gt;milliwatts&lt;/em&gt; per square meter:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Heat flows constantly from its sources within Earth to the surface. Total heat loss from Earth is estimated at 44.2 TW (4.42 × 10¹³ watts).[⁴] Mean heat flow is 65 mW/m² over continental crust and 101 mW/m² over oceanic crust.[⁴] This is 0.087 watt/square metre on average (0.03 percent of solar power absorbed by Earth[⁵]), but is much more concentrated in areas where the lithosphere is thin, such as along mid-ocean ridges (where new oceanic lithosphere is created) and near mantle plumes.[⁶]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Cited References&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;R. G. Barry and R. J. Chorley (2003), &lt;em&gt;Atmosphere, Weather and Climate&lt;/em&gt;, Routledge, London, 2003.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;J. T. Kiehl and Kevin E. Trenberth (1997), &amp;quot;Earth’s annual global mean energy budget&amp;quot;, &lt;em&gt;Bull. Amer. Meteor. Soc.&lt;/em&gt; &lt;strong&gt;78&lt;/strong&gt;, 197–208.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;K. E. Trenberth, J. T. Fasullo, and J. Kiehl (2009), &amp;quot;Earth’s global energy budget&amp;quot;, &lt;em&gt;Bull. Amer. Meteor. Soc.&lt;/em&gt; &lt;strong&gt;90&lt;/strong&gt;, 311–323.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Pollack, Henry N., et.al. (1993) &amp;quot;Heat flow from Earth's interior: Analysis of the global data set&amp;quot;, &lt;em&gt;Reviews of Geophysics&lt;/em&gt;, &lt;strong&gt;31&lt;/strong&gt;, 3, p. 273. Archived 2011-08-11 at the Wayback Machine. &lt;a href=&quot;https://doi.org/10.1029/93RG01249&quot; rel=&quot;noreferrer&quot;&gt;doi:10.1029/93RG01249&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;&amp;quot;Climate and Earth's Energy Budget&amp;quot;. NASA. 2009-01-14.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Richards, M. A.; Duncan, R. A.; Courtillot, V. E. (1989). &amp;quot;Flood Basalts and Hot-Spot Tracks: Plume Heads and Tails&amp;quot;. &lt;em&gt;Science&lt;/em&gt; &lt;strong&gt;246&lt;/strong&gt; (4926): 103–107. Bibcode:1989Sci...246..103R. &lt;a href=&quot;https://doi.org/10.1126/science.246.4926.103&quot; rel=&quot;noreferrer&quot;&gt;doi:10.1126/science.246.4926.103&lt;/a&gt;. PMID 17837768. S2CID 9147772.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="-1" LastEditDate="2023-03-17T16:27:45.830" LastActivityDate="2023-03-17T16:27:45.830" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25038" PostTypeId="1" CreationDate="2023-03-17T22:15:43.100" Score="2" ViewCount="32" Body="&lt;p&gt;Which countries require corporations to report their GHG emissions (eg tonnes of CO2 &lt;a href=&quot;https://en.wikipedia.org/wiki/Global_warming_potential&quot; rel=&quot;nofollow noreferrer&quot;&gt;or GWP&lt;/a&gt; emitted), and where can I find those numbers per company?&lt;/p&gt;&#xA;&lt;p&gt;I'm trying to find companies who do high-energy industrial manufacturing (eg steel production) with renewable energy power sources.&lt;/p&gt;&#xA;&lt;p&gt;For example, &lt;a href=&quot;https://en.wikipedia.org/wiki/Salzgitter&quot; rel=&quot;nofollow noreferrer&quot;&gt;Salzgitter&lt;/a&gt; is a major steel producer in Germany that's investing in hydrogen-powered electric arc furnaces powered by wind. I'd like to find-out the amount of steel they produce per year, divide that by the GWP that their production produces each year, and then compare that to other companies in the region (eg &lt;a href=&quot;https://en.wikipedia.org/wiki/ThyssenKrupp&quot; rel=&quot;nofollow noreferrer&quot;&gt;thyssenkrupp&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;Where can I find the actual GWP produced per company per year?&lt;/p&gt;&#xA;" OwnerUserId="28700" LastEditorUserId="28700" LastEditDate="2023-03-17T23:33:27.707" LastActivityDate="2023-03-17T23:33:27.707" Title="GHG emissions per company per year (carbon footprint database)" Tags="|greenhouse-gases|database|emissions|history|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="25039" PostTypeId="1" AcceptedAnswerId="25050" CreationDate="2023-03-18T08:16:29.953" Score="4" ViewCount="140" Body="&lt;p&gt;Let me explain: I am a physics student who did some basic earth science during my early high school days. But thinking about earth science makes me very curious about deeper topics, like how the oceans were formed, why the oceans are saline, how salinity of the oceans affects the climate pattern around the world and how weather patterns are altered by bio-geochemical changes.&lt;/p&gt;&#xA;&lt;p&gt;I have used Google to search for answers to such questions and had mixed success. So now I want to dive deeper into earth science with a dedicated book. I tried approaching Google for this, but the results were confusing.&lt;/p&gt;&#xA;&lt;p&gt;I would like to get some of the most trusted books on earth and climate science.&lt;/p&gt;&#xA;&lt;p&gt;Sorry if this question does not fit in prescribed pattern of the site.&lt;/p&gt;&#xA;" OwnerUserId="28702" LastEditorUserId="6298" LastEditDate="2023-03-21T04:10:56.413" LastActivityDate="2023-03-21T17:26:45.160" Title="Dedicated book to understand climate and ocean science" Tags="|climate|oceanography|earth-system|reference-request|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25041" PostTypeId="1" AcceptedAnswerId="25046" CreationDate="2023-03-19T02:13:33.770" Score="5" ViewCount="86" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Elbrus&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mount Elbrus&lt;/a&gt;, in the Caucasus region of Russia, 65 km southwest from Kislovodsk,   is a major, isolated volcano in the heart of a continent-continent collision zone. It is not normal for volcanoes to form in such settings (see e.g. &lt;a href=&quot;https://earthscience.stackexchange.com/q/23390/28708&quot;&gt;this question&lt;/a&gt;). How did Elbrus form? I have not been able to find any good resources online (any links would be welcome). Please also mention other examples of similar volcanoes if you are aware of them.&lt;/p&gt;&#xA;" OwnerUserId="28708" LastEditorUserId="2470" LastEditDate="2023-03-19T04:33:16.983" LastActivityDate="2023-03-20T23:10:29.017" Title="Formation of Mount Elbrus" Tags="|volcanology|tectonics|continent|orogeny|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25042" PostTypeId="1" CreationDate="2023-03-20T04:08:42.413" Score="4" ViewCount="42" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Saline_water#/media/File:Water_salinity_diagram.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;According to Wikipedia&lt;/a&gt; sea water is 34.7 parts per thousand salt.&lt;/p&gt;&#xA;&lt;p&gt;Between evaporation and precipitation it seems like this amount is kept largely in equilibrium but, during the last glacial maximum, a lot of this precipitation would have frozen to form glaciers.&lt;/p&gt;&#xA;&lt;p&gt;Since that precipitation didn't make it into the ocean it stands to reason that this would have increased the salinity of the oceans. And sure, if the amount of water held in the glaciers was a drop in the bucket compared to the water in the oceans then I guess it wouldn't have made much of a difference.&lt;/p&gt;&#xA;&lt;p&gt;But, &lt;a href=&quot;https://pubs.usgs.gov/fs/fs2-00/&quot; rel=&quot;nofollow noreferrer&quot;&gt;according to USGS&lt;/a&gt;: &amp;quot;global sea level was about 125 meters below today’s sea level at the last glacial maximum about 20,000 years ago&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;This kinda makes me wonder: how saline were the oceans during the last glacial maximum?&lt;/p&gt;&#xA;" OwnerUserId="3157" LastEditorUserId="18081" LastEditDate="2023-03-20T17:50:33.017" LastActivityDate="2023-03-20T17:50:33.017" Title="How saline were the earth's oceans during the Last Glacial Maximum?" Tags="|oceanography|glaciology|ice-age|salinity|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25043" PostTypeId="1" CreationDate="2023-03-20T04:22:17.317" Score="8" ViewCount="62" Body="&lt;p&gt;Quoting a sign in Redwood National Park:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Redwoods once covered large expanses of the world. Millions of years ago some of these redwoods were preserved as fossilized trees when volcanic ash buried them. Over time, the trees absorb silica from the ash, creating a stone replica. Where living tissue once was, rock now exists.&lt;/p&gt;&#xA;&lt;p&gt;In North America, redwood fossils have been found in Texas, Pennsylvania, Colorado, Wyoming, Oregon, Washington, California, Canada, Greenland, Alaska, and St. Lawrence Island. In Europe, fossils of redwoods have been found in France, Switzerland, Austria, Bohemia, Germany, England, and Spitzbergen. You can see fossil redwoods for yourself by visiting Yellowstone National Park in Wyoming, Florissant Fossil Beds National Monument in Colorado, or The Petrified Forest in Calistoga, California&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Sequoia_sempervirens&quot; rel=&quot;nofollow noreferrer&quot;&gt;Quoting Wikipedia&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The height of S. sempervirens is closely tied to fog availability; taller trees become less frequent as fog becomes less frequent. As S. sempervirens' height increases, transporting water via water potential to the leaves becomes increasingly difficult due to gravity&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;If you put those two facts together than it seems like either (1) the vast majority of the redwoods that existed millions of years ago fell short of their full potential height or (2) the Earth, millions of years ago, was a lot more foggy than it is today?&lt;/p&gt;&#xA;&lt;p&gt;If the latter than why would the Earth have been so much foggier?&lt;/p&gt;&#xA;" OwnerUserId="3157" LastEditorDisplayName="user28185" LastEditDate="2023-03-20T09:49:58.417" LastActivityDate="2023-03-20T09:49:58.417" Title="Was the Earth a lot foggier millions of years ago?" Tags="|meteorology|earth-history|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25044" PostTypeId="1" AcceptedAnswerId="25045" CreationDate="2023-03-20T11:42:56.543" Score="1" ViewCount="169" Body="&lt;p&gt;Assumptions: Essentially all oxygen that's ever been present in the atmosphere originated from oxygenic photosynthesis. The production of an oxygen molecule during photosynthesis leads to the consumption of a carbon dioxide molecule. Likewise, we assume that the principal &lt;em&gt;consumer&lt;/em&gt; of O&lt;sub&gt;2&lt;/sub&gt; is the oxidation of carbon (e.g. through respiration or combustion), in which the consumption of an O&lt;sub&gt;2&lt;/sub&gt; molecule requires the production of a CO&lt;sub&gt;2&lt;/sub&gt; molecule. Therefore, without an external source or sink of CO&lt;sub&gt;2&lt;/sub&gt;, any increase in O&lt;sub&gt;2&lt;/sub&gt; requires an equivalent decrease in CO&lt;sub&gt;2&lt;/sub&gt;, and vice versa.&lt;/p&gt;&#xA;&lt;p&gt;We know that O&lt;sub&gt;2&lt;/sub&gt; levels rose to ~30% of the total atmosphere during the Carboniferous era. Thus, O&lt;sub&gt;2&lt;/sub&gt; levels fell by 9% in the 350 million years that followed. This appears to require a concomitant &lt;em&gt;increase&lt;/em&gt; in CO&lt;sub&gt;2&lt;/sub&gt; of 9%, by the assumptions above. Given that the current concentration of CO&lt;sub&gt;2&lt;/sub&gt; is merely 0.04%, &lt;strong&gt;where did all the CO&lt;sub&gt;2&lt;/sub&gt; go?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="28714" LastEditorDisplayName="user28185" LastEditDate="2023-03-22T14:20:53.307" LastActivityDate="2023-03-22T19:58:30.223" Title="How could oxygen levels have ever been higher if there is so little carbon dioxide present?" Tags="|atmosphere|co2|paleoclimatology|carbon-cycle|oxygen|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25045" PostTypeId="2" ParentId="25044" CreationDate="2023-03-20T13:13:57.707" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Where did all the CO&lt;sub&gt;2&lt;/sub&gt; go?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Shell organisms stored it in the sediments and rocks in the form of CaCO&lt;sub&gt;3&lt;/sub&gt;. This is known as the main sink of CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&lt;p&gt;There are other C sinks on the Earth, but lithosphere is the larger by far:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BVvV2.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BVvV2.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://gml.noaa.gov/education/info_activities/pdfs/TBI_co2_and_the_carbon_cycle.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user28185" LastEditorDisplayName="user28185" LastEditDate="2023-03-22T10:38:14.270" LastActivityDate="2023-03-22T10:38:14.270" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="25046" PostTypeId="2" ParentId="25041" CreationDate="2023-03-20T23:10:29.017" Score="4" Body="&lt;p&gt;It's a fairly dense analysis, but this paper seems to have your answer: &lt;a href=&quot;https://doi.org/10.1016/j.jvolgeores.2021.107173&quot; rel=&quot;nofollow noreferrer&quot;&gt;Young Silicic Magmatism of the Greater Caucasus, Russia, with implication for its delamination origin based on zircon petrochronology and thermomechanical modeling&lt;/a&gt;. It's also a cited in the paper mentioned in the comment by klanomath, though the figures aren't as appealing.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Thermomechanical modeling bolsters the existing idea that magmatism in&#xA;the Greater Caucasus is the result of the breakoff of a subducted slab&#xA;at ~5 Ma in what would be an otherwise amagmatic post-collisional&#xA;environment. Large volumes of silicic magmas were rapidly produced by&#xA;the intrusion of hot asthenosphere into a lithospheric window left&#xA;behind by the foundered slab. This material underwent decompression&#xA;melting and produced silicic magmas by heating and melting the crust.&#xA;Further silicic magmas were produced by the detachment and melting of&#xA;buoyant material from the foundering slab. Sometime after this initial&#xA;melting event, crustal thickening eclogitized the lower crust of the&#xA;continent formerly attached to the subducting slab, causing it to&#xA;delaminate along with the underlying continental lithosphere over a&#xA;region at least 200 km across. &lt;strong&gt;This produced a large surge of melting&#xA;in the upper mantle and accompanying mafic volcanism, possibly&#xA;explaining the existing high volcanic field in the Lesser Caucasus.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2023-03-20T23:10:29.017" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25047" PostTypeId="2" ParentId="25044" CreationDate="2023-03-21T00:10:14.513" Score="1" Body="&lt;h2&gt;It doesn't go anywhere, you don't need CO2 production to loose oxygen.&lt;/h2&gt;&#xA;&lt;p&gt;photosynthesis is water + CO&lt;sub&gt;2&lt;/sub&gt; into O&lt;sub&gt;2&lt;/sub&gt; and sugar. In this case the sugar is mostly cellulose. what happened in the carboniferous? Lignin bound massive cellulose (wood) evolved but almost nothing could digest it leading to burial being far more likely than today. At the same time mountain building features of Pangea make burial of peat and swamps a continuous process. Carbon gets buried Oxygen gets released. That is where the oxygen itself came from.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;You don't need CO&lt;sub&gt;2&lt;/sub&gt; production to get oxygen loss.&lt;/strong&gt;&#xA;Oxygen level fall naturally as it well, oxidizes stuff, mostly weathered of minerals and volcanics. There needs to be a continuous production of new oxygen to replace that. Today this effect is minimal but the continuous evolution of things that can live on land, and in dryer and dryer places would have noticeably increased this as weathering compared to today. Modern sediment source rock is much more oxidized as a whole that is why today the exchange of CO&lt;sub&gt;2&lt;/sub&gt; and oxygen biotically has a bigger effect. How much sediment is reworked stuff that is already oxidized increases over time but it is still fairly low at the time. The carbon/oxygen cycle is much more complex than just the two exchanging with each other.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nsf.gov/news/news_summ.jsp?cntn_id=124570&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nsf.gov/news/news_summ.jsp?cntn_id=124570&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0009254120302047&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/S0009254120302047&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/ncomms14379&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/ncomms14379&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2023-03-22T19:58:30.223" LastActivityDate="2023-03-22T19:58:30.223" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25048" PostTypeId="2" ParentId="370" CreationDate="2023-03-21T05:51:14.097" Score="0" Body="&lt;p&gt;As the earth rotates, when air moves from near the poles towards the equator, the radius of that part of the earth is larger, which means, the ground is moving faster and the air lags behind. When the air is moving from near the equator towards the poles, it travels to where the radius is smaller and ground speed lower, so the air races ahead, causing a cyclone in the southern hemisphere to rotate CW, and one in the northern hemisphere to rotate ACW. The Coriolis Effect will not affect the direction of air from the east or west, but it will be deflected by the vortex, and then help to push it around. (Any fluid approaching a common point, like a thermal up drought, or drain hole will tend to form a vortex, but the Coriolis Effect will decide which way, if the vortex is big enough). All cyclones have lower pressure inside due to the centrifugal force from the air turning, which keeps it going in a circle like a tornado, but not as concentrated, although the people in Darwin might disagree after Cyclone Tracy on the night of Christmas Eve 1974. The place looked like Hiroshima after the bomb.&lt;/p&gt;&#xA;&lt;p&gt;Incidentally, the Coriolis Effect is not a force. The air is just continuing roughly in a straight line like it was (ignoring ground friction, which slowly deflects it the other way), but the ground speed is different in different places, so, from the ground, it appears deflected until it gets into a vortex, where it actually is.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iBBvf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iBBvf.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28401" LastEditorUserId="28401" LastEditDate="2023-03-29T05:51:39.483" LastActivityDate="2023-03-29T05:51:39.483" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25049" PostTypeId="1" AcceptedAnswerId="25053" CreationDate="2023-03-21T16:23:05.087" Score="1" ViewCount="156" Body="&lt;p&gt;There are many types of rocks: igneous rocks, sedimentary rocks, and metamorphic rocks. Some rocks are simply huge. Some of them are tiny. Is there a theoretical upper limit on the size of a rock, and what is it based on?&lt;/p&gt;&#xA;" OwnerUserId="22908" LastEditorUserId="22908" LastEditDate="2023-03-21T17:38:35.137" LastActivityDate="2023-03-22T13:56:32.803" Title="Is there a theoretical maximum size limit for a rock?" Tags="|geology|rocks|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="25050" PostTypeId="2" ParentId="25039" CreationDate="2023-03-21T17:26:45.160" Score="3" Body="&lt;p&gt;there are very different books on this topic. Therefore, a concrete selection is somewhat more complex.&lt;/p&gt;&#xA;&lt;p&gt;But to gain a good insight into biogeochemical processes, I would recommend the book:&lt;/p&gt;&#xA;&lt;p&gt;Biogeochemistry An Analysis of Global Change 4th Edition - August 7, 2020. But at 80 euros, it's not cheap at all. But it explains perfectly how biogeochemical cycles work on earth and how they change with climate change. This is my personal favourite on the subject of biogeochemistry.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Swqls.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Swqls.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, if you want to learn about the formation of oceans, I would recommend the book: Earth System History by Steven M. Stanley et al. In this book you will find the history of the earth broken down very well in my opinion.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8FD00.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8FD00.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;And a third book that fits your question well and that I like to use is the book: Torsvik, T.H., Cocks, R.M. (2017) Earth History and Palaeogeography. The title is self-explanatory.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HGQHh.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HGQHh.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;You may see that it is very difficult to find only one book, but these are three books that can be read well with different levels of knowledge. This means that you as a non-expert reader can learn just as much as a reader who has studied the subject.&lt;/p&gt;&#xA;&lt;p&gt;But if you need something more specific, post it in the comments and I'll see what I can recommend. More specific topics include how ocean currents have shifted due to climate change or the role of oceans in the Earth system.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2023-03-21T17:26:45.160" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25051" PostTypeId="2" ParentId="24048" CreationDate="2023-03-21T19:38:29.983" Score="1" Body="&lt;p&gt;I'm sure there are cheaper versions for it. But to answer your question, it's more of a investment for a lifetime and no need to worry about buying new ones in the next 20-30 years.&lt;/p&gt;&#xA;" OwnerUserId="28724" LastActivityDate="2023-03-21T19:38:29.983" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25052" PostTypeId="2" ParentId="25044" CreationDate="2023-03-21T23:17:20.510" Score="1" Body="&lt;p&gt;The assumptions you state are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Oxygen only exists in the atmosphere, as either O2 or CO2&lt;/li&gt;&#xA;&lt;li&gt;Carbon only exists in the atmosphere as CO2 and above surface in the form of organic matter&lt;/li&gt;&#xA;&lt;li&gt;Oxidization of organic matter and photosynthesis are the only ways in which oxygen and carbon move through their respective reservoirs.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;But all of these assumptions are, in essence, wrong:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Carbon dioxide dissolves in the ocean where it is then sequestered via CaCO3 into sedimentary rocks and from there into the Earth mantle. There were ~600 gigatons of carbon in the atmosphere in the pre-industrial era, about 4 times that much in the biosphere (organic carbon), and about 60 times that much in the oceans (about 38,000 gigatons of carbon). (&lt;a href=&quot;https://worldoceanreview.com/en/wor-1/ocean-chemistry/co2-reservoir/#:%7E:text=The%20ocean%2C%20with%20around%2038%2C000,before%20people%20began%20to%20drastically&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;) There is far far more carbon even in the crust and the mantle: About &lt;span class=&quot;math-container&quot;&gt;$10^{8}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$10^{10}$&lt;/span&gt; gigatons, respectively. (&lt;a href=&quot;https://en.wikipedia.org/wiki/Geochemistry_of_carbon#:%7E:text=Earth%27s%20mantle%20is%20a%20significant,of%20100%20between%20different%20parts.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;li&gt;A certain fraction of the carbon is also moved from the atmosphere via photosynthesis into rocks by way of hydrocarbons (oil, gas, and coal). And then, of course, some of that is released again as well: By way of us burning fossil fuels, but also by way of direct methane and oil leaks from underground reservoirs to the ocean or the atmosphere; by oxidation of these fossil fuels by bacteria if oxygen can reach these reservoirs; or by coal seam fires.&lt;/li&gt;&#xA;&lt;li&gt;Oxygen, too, is bound up elsewhere. An example are oxidized iron rocks -- &lt;a href=&quot;https://en.wikipedia.org/wiki/Banded_iron_formation&quot; rel=&quot;nofollow noreferrer&quot;&gt;banded iron formations&lt;/a&gt; -- in which oxygen was drawn out of the atmosphere-ocean system and sequestered into rocks.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="5259" LastEditorUserId="5259" LastEditDate="2023-03-22T03:08:26.103" LastActivityDate="2023-03-22T03:08:26.103" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="25053" PostTypeId="2" ParentId="25049" CreationDate="2023-03-22T09:09:09.160" Score="2" Body="&lt;p&gt;In itself, it is very complex to claim what a stone is. However, the industry has to define it. For example, if a track ballast has to be covered with &amp;quot;stones&amp;quot;, the stone factory has to know what they have to deliver. Therefore there is the following classification:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DmI7j.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DmI7j.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://en.wikipedia.org/wiki/Grain_size&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Grain_size&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, if the geology is to determine how big, for example, rocks or mountains become, it must be taken into account that as the size increases, the surface area exposed to erosion increases, which is one of the limiting factors for rocks or mountains not being able to grow indefinitely high.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2023-03-22T09:09:09.160" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25054" PostTypeId="2" ParentId="25049" CreationDate="2023-03-22T13:56:32.803" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Uluru&quot; rel=&quot;nofollow noreferrer&quot;&gt;Uluru&lt;/a&gt;, in central Australia, is also referred to as a &lt;a href=&quot;https://en.wikipedia.org/wiki/Inselberg&quot; rel=&quot;nofollow noreferrer&quot;&gt;inselberg&lt;/a&gt; or a &lt;a href=&quot;https://en.wikipedia.org/wiki/Monolith&quot; rel=&quot;nofollow noreferrer&quot;&gt;monolith&lt;/a&gt;. It was once known as Ayers Rock before its indigenous name was adopted.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://uluru-australia.com/about-uluru/uluru-facts/&quot; rel=&quot;nofollow noreferrer&quot;&gt;dimensions of Uluru&lt;/a&gt; are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Length - 3.6 km&lt;/li&gt;&#xA;&lt;li&gt;Width  - 1.9 km&lt;/li&gt;&#xA;&lt;li&gt;Height above ground - 348 m&lt;/li&gt;&#xA;&lt;li&gt;Extent into the ground - approximately 2.5 km&lt;/li&gt;&#xA;&lt;li&gt;Perimeter around its contact with the ground - 9.4 km&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Less well known is &lt;a href=&quot;https://en.wikipedia.org/wiki/Mount_Augustus_(Western_Australia)&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mount Augustus&lt;/a&gt;, in Western Australia, which is another inselberg. Its central ridge is 8 km long and it is approximately 860 m above ground. It covers an area of 4795 ha. It is more than twice the size of Uluru.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-03-22T13:56:32.803" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25055" PostTypeId="1" CreationDate="2023-03-22T15:27:23.457" Score="1" ViewCount="31" Body="&lt;p&gt;The Figure &amp;quot;&lt;a href=&quot;https://www.ipcc.ch/report/ar6/syr/figures/summary-for-policymakers/figure-spm-3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Projected risks and impacts of climate change on natural and human systems at different global warming levels&lt;/a&gt;&amp;quot; has this to say on species loss (only part of the image):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/CEZLS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CEZLS.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I can't quite make it out for the 2°C scenario, but for 3°C upward huge swathes of the pacific ocean are shown to lose 100% of the species to be &amp;quot;exposed to potentially dangerous temperature conditions.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;My questions are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Does this purely look at temperature changes, or also CO2 uptake and ocean acidification?&lt;/li&gt;&#xA;&lt;li&gt;What physical change of ocean temperature does this represent?&lt;/li&gt;&#xA;&lt;li&gt;Over what timescale?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="117" LastActivityDate="2023-03-22T15:27:23.457" Title="IPCC 6 - What's the background of possible marine species loss?" Tags="|climate-change|oceanography|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25056" PostTypeId="2" ParentId="24495" CreationDate="2023-03-23T00:03:51.970" Score="1" Body="&lt;p&gt;Just wondering about your statement above: &amp;quot;Since this higher layer has usually lower temperature, less energy is irradiated an, therefore, the planet will warm up&amp;quot;.  This doesn't sound right.  For one thing, temperature at any layer is not a passive variable: if radiation (absorption and emission) is happening at a higher level, then the temperature at that level should rise too.&lt;/p&gt;&#xA;&lt;p&gt;As I understand it, the &amp;quot;greenhouse effect&amp;quot; is not that the planet warms because less energy is irradiated.  There is still approximately overall radiative balance, i.e., energy radiated out balances energy absorbed coming in.  The blackbody temperature of the earth as a whole remains about the same - lets say, for the sake of argument, that it's 255K.  With more CO2, as you illustrate above, outgoing radiation leaves from higher altitudes, and so the 255K surface rises to a higher altitude as well to maintain radiative balance.  However, the temperature below that 255K level more or less continues to follow the moist adiabatic lapse rate (in the tropics), or even just the same lapse rate that it had before, but now the temperature increases along that lapse rate for a greater vertical distance, and so the surface temperature is raised.  (The atmosphere is not just in radiative balance, but in radiative-convective balance).  The very simplest &amp;amp; crudest picture of this is to take a typical temperature profile from surface to stratosphere (i.e., with a minimum at the tropopause), and simply lift it up a bit.  You'll have to extend the bottom of the curve a bit now to a higher surface temperature, while the stratosphere will become cooler.&lt;/p&gt;&#xA;&lt;p&gt;Since clouds are good blackbodies (i.e., IR absorbers and emitters), this also explains why more high clouds (i.e., above the ~255k level) should raise surface temperatures, while more low clouds should lower them.&lt;/p&gt;&#xA;&lt;p&gt;This warmer surface temperature and cooler (lower) stratosphere are characteristic of the greenhouse effect as explained in the classic Manabe &amp;amp; Wetherald JAS paper from 1967 (&amp;quot;Thermal Equilibrium of the Atmosphere with a Given Distribution of Relative Humidity&amp;quot;, &lt;a href=&quot;https://doi.org/10.1175/1520-0469(1967)024%3C0241:TEOTAW%3E2.0.CO;2&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1175/1520-0469(1967)024%3C0241:TEOTAW%3E2.0.CO;2&lt;/a&gt;) - a paper which probably helped Manabe win his Nobel prize a couple of years ago.&lt;/p&gt;&#xA;" OwnerUserId="28727" LastActivityDate="2023-03-23T00:03:51.970" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25058" PostTypeId="1" CreationDate="2023-03-23T18:13:00.277" Score="1" ViewCount="4225" Body="&lt;p&gt;Where is the safest place on Earth in relation the magnetic poles as it is moving that will provide the most protection against solar radiation? I imagine the topography may effect the magnetic fields.&lt;/p&gt;&#xA;" OwnerUserId="21150" LastEditorUserId="2470" LastEditDate="2023-03-23T18:32:19.070" LastActivityDate="2023-10-31T21:14:31.483" Title="Safest place on Earth during the pole shift" Tags="|meteorology|geomagnetism|poles|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25060" PostTypeId="1" CreationDate="2023-03-24T14:17:25.910" Score="4" ViewCount="87" Body="&lt;p&gt;I don't know where else to post this.&lt;/p&gt;&#xA;&lt;p&gt;I am reading a Geotechnical engineering textbook by B.M. Das, 6th edition.&lt;/p&gt;&#xA;&lt;p&gt;Problem 3.1 is as follows:&lt;/p&gt;&#xA;&lt;p&gt;For a given soil, show that&#xA;&lt;span class=&quot;math-container&quot;&gt;$$e=\frac{\gamma_{sat} - \gamma_w}{\gamma_d - \gamma_{sat} + \gamma_w}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$e=\frac{V_v}{V_s}$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$V_v$&lt;/span&gt; is the volume of voids I a specific soil and &lt;span class=&quot;math-container&quot;&gt;$V_s$&lt;/span&gt; is the volume of solid material.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\gamma_{sat}$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\gamma_d$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$\gamma_w$&lt;/span&gt; are the unit weight of saturated soil (all voids filled with water), dry soil (no water) and water in &lt;span class=&quot;math-container&quot;&gt;$kN/m^3$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;My attempt:&#xA;&lt;span class=&quot;math-container&quot;&gt;$W_s,W_w$&lt;/span&gt; are the weight of solids and weight of water in the saturated sample. Total volume is &lt;span class=&quot;math-container&quot;&gt;$V_{tot}=V_s+V_v=1$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$e=\frac{\gamma_{sat} - \gamma_w}{\gamma_d - \gamma_{sat} + \gamma_w}=\frac{\frac{W_s+W_w}{V_{tot}}-\frac{W_w}{V_v}}{\frac{W_s-W_s-W_w}{V_{tot}}+\frac{W_w}{V_v}}=\frac{V_v(W_s+W_w)-W_w}{W_w - V_vW_w}=\frac{V_vW_s+W_w(V_v-1)}{W_wV_s}=e*\frac{W_s}{W_w}-1$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;I can't find a way beyond this and something is wrong. We can move around the variables to get &lt;span class=&quot;math-container&quot;&gt;$e=\frac{V_vW_s}{V_sW_w}-1=\frac{\gamma_s}{\gamma_w}-1=G_s-1$&lt;/span&gt;&#xA;,&lt;span class=&quot;math-container&quot;&gt;$G_s$&lt;/span&gt; is defined as the specific gravity and is constant for the solid material regardless of the void ratio (&lt;span class=&quot;math-container&quot;&gt;$e$&lt;/span&gt;). Therefore &lt;span class=&quot;math-container&quot;&gt;$e=G_s-1$&lt;/span&gt; must be wrong because &lt;span class=&quot;math-container&quot;&gt;$e$&lt;/span&gt; is supposed to be variable in a soil with constant &lt;span class=&quot;math-container&quot;&gt;$G_s$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="28735" LastEditorUserId="2470" LastEditDate="2023-03-25T01:54:58.253" LastActivityDate="2023-03-25T01:54:58.253" Title="Geotechnology: Prove a formula, calculated with unit weights, for void ratio" Tags="|geophysics|soil|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25062" PostTypeId="1" CreationDate="2023-03-25T06:04:42.827" Score="1" ViewCount="68" Body="&lt;p&gt;I want to run WRF-Chem with one-way nesting because of the limitations of my system (a linux server with 378 GB of RAM and 32 processors). I have gone through the WRF user guide, which explained how to do one-way nesting using 'ndown.exe'. Also, I found the following lines on the webpage (WRF Namelist.input Best Prac):&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;When feedback is off , it is equivalent to a one-way nested run, since nest results are not reflected in the parent domain.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;So, my question is: Are both processes equally efficient as far as computational cost is concerned? Or is using &amp;quot;ndown.exe&amp;quot; faster than setting &amp;quot;feedback&amp;quot; to &amp;quot;0&amp;quot;? Which way is better for one-way nesting?&#xA;Can anyone please guide me in this regard? That will be greatly appreciated.&#xA;Thanking you.&#xA;With regards,&#xA;Ankan&lt;/p&gt;&#xA;" OwnerUserId="28246" LastActivityDate="2023-03-25T06:04:42.827" Title="Which way is the more computationally efficient for running WRF-Chem with one way nesting: (a) by setting feedback to '0' or (b) using ndown.exe?" Tags="|atmosphere-modelling|wrf|wrf-chem|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25063" PostTypeId="1" CreationDate="2023-03-25T08:06:21.543" Score="3" ViewCount="76" Body="&lt;p&gt;CaCO&lt;sub&gt;3&lt;/sub&gt; dissolves below the &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonate_compensation_depth&quot; rel=&quot;nofollow noreferrer&quot;&gt;Carbonate Compensation Depth (CCD)&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;However, &lt;a href=&quot;https://pubs.geoscienceworld.org/sepm/books/book/1144/chapter-abstract/10571036/Preservation-of-Foraminifera?redirectedFrom=PDF&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt; suggests that some CaCO&lt;sub&gt;3&lt;/sub&gt; can exist below the CCD.&lt;/p&gt;&#xA;&lt;p&gt;My question arises from a discussion in &lt;a href=&quot;https://earthscience.stackexchange.com/a/25052/28185&quot;&gt;this answer&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The question is whether some of the CO&lt;sub&gt;2&lt;/sub&gt; emitted by volcanoes in subduction zones comes from the melting of CaCO&lt;sub&gt;3&lt;/sub&gt; sediments in the slag.&lt;/p&gt;&#xA;&lt;p&gt;Has there been any isotopic study clarifying the provenance of CO&lt;sub&gt;2&lt;/sub&gt; from volcanoes in subduction zones?&lt;/p&gt;&#xA;" OwnerDisplayName="user28185" LastEditorDisplayName="user28185" LastEditDate="2023-03-29T10:38:47.923" LastActivityDate="2023-03-29T10:38:47.923" Title="Can $\ce{CaCO3}$ shells contribute to $\ce{CO2}$ emissions in volcanoes within subduction zones?" Tags="|geochemistry|co2|carbon-cycle|subduction|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="25065" PostTypeId="1" CreationDate="2023-03-27T07:40:01.610" Score="3" ViewCount="102" Body="&lt;p&gt;Discussing the relative risk of tornadoes vs earthquakes with a friend got me thinking about roughly how many people have been in tornadoes in their lifetime, which may be a statistic that would help put some minds at ease in tornado-prone areas, or help people better understand what they may see in various places.&lt;/p&gt;&#xA;&lt;p&gt;I've seen various comparisons of &lt;em&gt;deaths&lt;/em&gt; from natural disasters.  They certainly change depending on the sampling period, as protection, warning, and even occurrence frequency of different disasters changes over time.  (And what exactly counts as a death from each disaster)  (&lt;a href=&quot;https://www.prb.org/resources/which-types-of-disasters-are-the-deadliest-in-the-u-s-the-answer-is-surprising/&quot; rel=&quot;nofollow noreferrer&quot;&gt;These values seem to offer reasonable estimates for adults in the US to me.&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;But I'd think it's just as meaningful to identify how much various disasters are directly dealt with.&lt;/p&gt;&#xA;&lt;p&gt;I remember seeing an article 20 years ago from the Oklahoma Climatological Survey the &lt;em&gt;average&lt;/em&gt; return period in some areas in central Oklahoma may be somewhere vaguely between every 1000 years to every 10000 years (obviously there are both &lt;a href=&quot;https://www.foxla.com/news/tornado-los-angeles-montebello&quot; rel=&quot;nofollow noreferrer&quot;&gt;cities and even specific points&lt;/a&gt; that happen to get them more often).&lt;/p&gt;&#xA;&lt;p&gt;I can think of some ways to estimate/document such values... so what can you guys come up with?&lt;/p&gt;&#xA;&lt;p&gt;For simplicity, let's say USA as the main goal.  Bonuses for state calculations (Oklahoma in specific)... and also if you want to offer comparison to other disasters (though those estimates may be better as separate questions?)&lt;/p&gt;&#xA;&lt;p&gt;Actual data (studies, papers, etc) would of course be best, but I'm guessing that may be very limited and also perhaps distorted by what data has been recorded... so estimates of the actual values with &lt;strong&gt;well described&lt;/strong&gt; reasonings/source data would be great.&lt;/p&gt;&#xA;&lt;p&gt;Information is power, and I can see this type of statistic being useful to folks in understanding life and the world around them.&lt;/p&gt;&#xA;&lt;p&gt;** (I do realize that how you define &amp;quot;in a tornado&amp;quot; also likely greatly alters values. Could go by various tornado windspeeds, or just base it on tornado path dimensions given by storm surveys. As long as it is indicated/makes some sense)&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2023-04-04T22:08:12.020" LastActivityDate="2023-04-04T22:08:12.020" Title="What is a rough estimate for the number of people who have been in a tornado in their lifetime?" Tags="|meteorology|climatology|natural-disasters|tornado|" AnswerCount="0" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="25066" PostTypeId="1" CreationDate="2023-03-27T16:13:45.793" Score="2" ViewCount="58" Body="&lt;p&gt;This is a sea/ocean wave image which can be found in several places on the internet. I cannot find its origin and any image search did not yield conclusive results. It may even be a render.&lt;/p&gt;&#xA;&lt;p&gt;Question: is there any natural phenomenon which can produce such a wave? A seabed discontinuity? Two water masses of different temperature/salination? Would it produce the foam? Why does the left part seem to flow over the right part at places?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AcDOU.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AcDOU.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28744" LastActivityDate="2023-03-27T16:13:45.793" Title="Sea waves with perpendicular discontinuity" Tags="|oceanography|waves|sea-floor|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25068" PostTypeId="1" CreationDate="2023-03-29T18:22:47.550" Score="2" ViewCount="64" Body="&lt;p&gt;In the literature, there are graphical (approximate) ways to estimate AEV from the soil water retention curve. I wonder, how can one more accurately estimate AEV according to its definition: the suction value at the transition from a saturated to an unsaturated state.&lt;/p&gt;&#xA;&lt;p&gt;Assuming one has volumetric water content (VWC) vs. suction measurements from laboratory tests (HYPROP test), how can we leverage these values to estimate AEV?&lt;/p&gt;&#xA;&lt;p&gt;Is it sensible to choose the suction value corresponding to the second largest VWC as the AEV?&lt;/p&gt;&#xA;" OwnerUserId="20807" LastEditorUserId="20807" LastEditDate="2023-04-18T23:44:30.877" LastActivityDate="2023-04-18T23:44:30.877" Title="How to accurately estimate air-entry value (AEV) suction for soils?" Tags="|hydrology|soil-science|hydrogeology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25069" PostTypeId="1" CreationDate="2023-03-30T05:48:58.650" Score="3" ViewCount="56" Body="&lt;p&gt;A &lt;a href=&quot;https://en.wikipedia.org/wiki/Gustnado&quot; rel=&quot;nofollow noreferrer&quot;&gt;gustnado&lt;/a&gt; is a landspout (i.e. a &amp;quot;mini-tornado&amp;quot;) that isn't connected to the ambient cloud base (if there is any). Mt Everest, the highest point on Earth, there is nothing &amp;quot;in the way&amp;quot; of colliding winds to form a snow gustnado on the summit. Cumulonimbus clouds can be as high as sixty thousand feet so perhaps even such gustnado could become a landspout (or snowspout). Is there enough area on or near the summit of Mt Everest (or another mountain in the Himalaya or on K2) and the right conditions possible for a snow gustnado or similar whirl spouts to form and persist for some time (and for how long) there?&lt;/p&gt;&#xA;" OwnerUserId="28130" LastActivityDate="2023-03-30T05:48:58.650" Title="Do snow gustnadoes or anything similar occur at or near the summits of the highest Himalayas such as Mt Everest?" Tags="|meteorology|mountains|snow|tornado|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25070" PostTypeId="2" ParentId="23993" CreationDate="2023-03-30T07:25:54.307" Score="4" Body="&lt;p&gt;Based on the comments and after a lot of trial and error plus reading carefully the Miepython documentation (!), I managed to answer my question:&lt;/p&gt;&#xA;&lt;p&gt;For the problem that I wasn't able to reproduce scattering and backscatter efficiencies &lt;span class=&quot;math-container&quot;&gt;$qsca$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$qback$&lt;/span&gt; (or corresponding cross sections &lt;span class=&quot;math-container&quot;&gt;$\sigma$&lt;/span&gt; in the first plot from values of the phase function in the second plot (update) in my question: I had two problems, or better say there were two pitfalls:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;I made an equidistant &lt;span class=&quot;math-container&quot;&gt;$\vartheta$&lt;/span&gt;-vector and converted to &lt;span class=&quot;math-container&quot;&gt;$mu = cos(\vartheta)$&lt;/span&gt;, calculated the phase function &lt;span class=&quot;math-container&quot;&gt;$p(\mu)$&lt;/span&gt; and plotted it as polar plot and histogram, which I tried then to integrate (sum up). That was of course not working as &lt;span class=&quot;math-container&quot;&gt;$\mu = cos(\vartheta)$&lt;/span&gt; is no longer equidistant. Now I'm doing an equidistant &lt;span class=&quot;math-container&quot;&gt;$\mu=cos(\vartheta)$&lt;/span&gt;-vector for calculation and integration. For plotting against &lt;span class=&quot;math-container&quot;&gt;$\vartheta$&lt;/span&gt; I just calculate &lt;span class=&quot;math-container&quot;&gt;$\vartheta$&lt;/span&gt; from &lt;span class=&quot;math-container&quot;&gt;$\mu$&lt;/span&gt; using &lt;span class=&quot;math-container&quot;&gt;$arccos()$&lt;/span&gt;. The result is non-equidistant datapoints in the histogram then, but when the resolution is high enough, you don't see it..&lt;/li&gt;&#xA;&lt;li&gt;There is a normalisation of the phase function in miepython, which is by default set to the single scattering albedo &lt;span class=&quot;math-container&quot;&gt;$a = qsca/qext$&lt;/span&gt;. So after summing up (integrating), to get &lt;span class=&quot;math-container&quot;&gt;$qsca$&lt;/span&gt; you need to multiply by &lt;span class=&quot;math-container&quot;&gt;$qext$&lt;/span&gt;. (But there are other options you can pass to Miepython for normalisation, the default is just &lt;span class=&quot;math-container&quot;&gt;$qsca/qext$&lt;/span&gt;... see &lt;a href=&quot;https://miepython.readthedocs.io/en/latest/03a_normalization.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://miepython.readthedocs.io/en/latest/03a_normalization.html&lt;/a&gt;)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;With this, I could reproduce values for &lt;span class=&quot;math-container&quot;&gt;$qsca$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$qback$&lt;/span&gt; at 500 nm. Here is the code:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import numpy as np&#xA;import miepython&#xA;import matplotlib.pyplot as plt&#xA;import matplotlib&#xA;matplotlib.rcParams.update({'font.size': 10})&#xA;&#xA;###############################################################################&#xA;# Parameters&#xA;###############################################################################&#xA;m = 1.335 - 1E-9j  # complex refractive index for water droplet at 500 nm from https://refractiveindex.info/?shelf=main&amp;amp;book=H2O&amp;amp;page=Daimon - 24.0C&#xA;lambda0 = 0.5 # in mu, i.e. 500 nm&#xA;diameter = 1 # in mu&#xA;r = 0.5*diameter  # radius of aerosol&#xA;x = 2*np.pi*r/lambda0 # size parameter&#xA;&#xA;###############################################################################&#xA;# Miepython calculation&#xA;# - Calculate scattering efficiencies&#xA;# - Calculate phase function and plot as polar plot and histogram&#xA;###############################################################################&#xA;mu = np.linspace(1,-1,100001) # make mu eqidistant and calculate (for the plots) theta  from it, not vice versa (important as we integrate later the histogram, which is a function of mu, so mu needs to be equidistant for easy sum up -&amp;gt; integrating)&#xA;theta = np.arccos(mu)*180/np.pi&#xA;&#xA;# Calculate extinction, scattering and backscatter efficiency&#xA;qext500, qsca500, qback500, g2_500 = miepython.mie(m,x)&#xA;&#xA;# Now calculate the phase function&#xA;normalisation='albedo' # default is albedo a = qsca/qext, see https://miepython.readthedocs.io/en/latest/03a_normalization.html&#xA;p_mu = miepython.i_unpolarized(m, x, mu, normalisation) # p_mu is now normalised to a = qsca/qext&#xA;# Test alternative way of calculating the phase function:&#xA;s1, s2 = miepython.mie_S1_S2(m, x, mu)&#xA;phase = (np.abs(s1)**2 + np.abs(s2)**2 )/2&#xA;if np.allclose(p_mu, phase):&#xA;    print('p_mu and phase are the same vectors')&#xA;&#xA;# plot phase function as polar plot and histogram&#xA;fig, (ax1, ax2) = plt.subplots(1,2,figsize=(12,5))&#xA;ax1=plt.subplot(121, projection='polar')&#xA;ax1.plot(theta/180*np.pi, p_mu, color='blue')&#xA;ax1.set_title(r'm = ' + str(np.around(m,9)) + ', d = '+str(diameter) + r' &lt;span class=&quot;math-container&quot;&gt;$\mu$&lt;/span&gt;m, &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt; = ' + str(np.around(1000*lambda0,0)) + r' nm')&#xA;&#xA;ax2 = plt.subplot(122)&#xA;ax2.plot(theta, p_mu)&#xA;ax2.set_xlabel(r'&lt;span class=&quot;math-container&quot;&gt;$\vartheta$&lt;/span&gt; (&lt;span class=&quot;math-container&quot;&gt;$^\circ$&lt;/span&gt;)')&#xA;ax2.set_ylabel('Unpolarized Scattered light [1/sr]')&#xA;ax2.grid(which = 'minor', color='grey', linestyle=':')&#xA;ax2.grid(which = 'major', color='grey', linestyle=':')&#xA;ax2.set_title(r'm = ' + str(np.around(m,9)) + ', d = '+str(diameter) + r' &lt;span class=&quot;math-container&quot;&gt;$\mu$&lt;/span&gt;m, &lt;span class=&quot;math-container&quot;&gt;$\lambda$&lt;/span&gt; = ' + str(np.around(1000*lambda0,0)) + r' nm')&#xA;&#xA;plt.tight_layout()&#xA;plt.show()&#xA;&#xA;fig.savefig('phase function.png', dpi=fig.dpi, bbox_inches='tight')&#xA;  &#xA;###############################################################################&#xA;# Now integrate histogram to reproduce scattering and backscatter effiencies &#xA;###############################################################################&#xA;# print values for comparison&#xA;print('qback500 = ' + str(qback500))&#xA;print('qsca500 = ' + str(qsca500))&#xA;print('qext500 = ' + str(qext500))&#xA;print('qsca and qext is almost the same, because of almost no absorption (imaginary part of complex refractive index, so extinction (loss) is mainly caused by scattering...)')&#xA;&#xA;print('\nNow calculating the scattering efficency from the phase function:')&#xA;&#xA;# spacing dmu for integration&#xA;oben = np.abs(mu[1:])&#xA;unten = np.abs(mu[:-1])&#xA;dmu = np.mean(np.abs(oben - unten))&#xA;print('\ndmu = ' + str(dmu))&#xA;print('dmu is the spacing on the mu = cos(theta) axis')&#xA;&#xA;# qsca from histogram:&#xA;print('Integration of phase function over full solid angle:')&#xA;print('- There is no dependency on the azimuth, so integration over azimuth gives 2*pi and the remaining integration is over mu only.')&#xA;print('- The integration over mu is from 1 to -1, i.e. from theta=0° to 180°')&#xA;integral_p_mu = 2*np.pi*dmu*np.sum(p_mu)&#xA;print('Integral over p_mu histogram = ' + str(integral_p_mu))&#xA;# To get qsca from this, remind that p_mu was normalised to a = qsca/qext. Thus, to get qsca, one needs to multiply the obtained result here with qext:&#xA;print('\nqsca calculated from phase function = ' + str(integral_p_mu * qext500))&#xA;&#xA;print('\nBackscattering efficency calculated from physe function')&#xA;idx180 = np.where(np.abs(180 - theta) &amp;lt; 0.01)[0][0] # index of backward direction&#xA;# Again, we need to multiply by qext because of the normalisation &#xA;# We use only the 180° datapoint of the phase function, but still need to integrate over the solid angle, which just gives 4*pi')&#xA;print('p_mu[idx180]*qext500*4*np.pi = ' + str(p_mu[idx180]*qext500*4*np.pi))&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;And the answer to my original question is:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$qsca$&lt;/span&gt; is the total scattering efficiency in all directions (integration over a full sphere of &lt;span class=&quot;math-container&quot;&gt;$4\pi$&lt;/span&gt;), i.e. not only forward half-dome or so..&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$qback$&lt;/span&gt; is scattering in the backward direction of &lt;span class=&quot;math-container&quot;&gt;$180^\circ$&lt;/span&gt; only (one single direction, not the entire rear half-dome or so...)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="27156" LastEditorUserId="2470" LastEditDate="2023-03-30T23:51:45.483" LastActivityDate="2023-03-30T23:51:45.483" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25071" PostTypeId="1" CreationDate="2023-03-30T19:05:24.183" Score="2" ViewCount="22" Body="&lt;p&gt;Is the horizontal radius of a cloud correlated in some way with the cloud height, or are these two independent variables?&lt;/p&gt;&#xA;" OwnerUserId="601" LastActivityDate="2023-03-30T19:05:24.183" Title="Correlation between cloud height and radius" Tags="|meteorology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25073" PostTypeId="1" CreationDate="2023-04-02T14:55:23.557" Score="3" ViewCount="53" Body="&lt;p&gt;I am doing something with &lt;a href=&quot;https://www.ospo.noaa.gov/Products/atmosphere/ascat/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ASCAT&lt;/a&gt; which is measuring backscatter to reflect the status of soil moisture. Some research indicated that VV polarization is much more suitable for soil moisture measurement than HH. Why is that? I only know that the electro vector of VV is within the vertical plane of the oscillation of the microwave. But why is it more suitable for soil moisture?&lt;/p&gt;&#xA;" OwnerUserId="14056" LastEditorUserId="6298" LastEditDate="2023-04-02T19:30:36.830" LastActivityDate="2023-04-02T19:30:36.830" Title="Question about VV and HH polarizations in radar" Tags="|remote-sensing|soil-moisture|radar|radiative-transfer|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25074" PostTypeId="1" CreationDate="2023-04-03T13:41:36.247" Score="1" ViewCount="22" Body="&lt;p&gt;TEMIS NO2 tropospheric Data by KMNI Netherland is retrieved in TOMIS (ASCII) format. My issue is to convert the said format in to ESRI Gird format or any other Raster format to analyze the  retrieved data file in ArcGIS format. Thanks&lt;/p&gt;&#xA;" OwnerUserId="28772" LastActivityDate="2023-04-03T13:41:36.247" Title="How we convert TOM" Tags="|remote-sensing|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25075" PostTypeId="1" CreationDate="2023-04-03T16:59:10.703" Score="3" ViewCount="146" Body="&lt;p&gt;I live in Brazil, around 200 km from the nearest coast.&lt;/p&gt;&#xA;&lt;p&gt;I'm looking to move to Rio de Janeiro (a coastal city) to study at the Federal University of Rio, which is basically on an island (&lt;a href=&quot;https://www.google.com/maps/place/Ilha+do+Fund%C3%A3o/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ilha do Fundão&lt;/a&gt;). It's not an elevated place, just a common coastal site. It is an area of almost no seismic activity, and not a spot with a hurricane history.&lt;/p&gt;&#xA;&lt;p&gt;I'd be there for at least 5 years to complete my degree.  But I've never lived in a coastal city and have heard there's concern of changes that could be dangerous.&lt;/p&gt;&#xA;&lt;p&gt;Among the things I'm worried about: is the sea level rising... and is it going to happen rapidly? Is it so much that I could drown while I'm at a class or something?&lt;br /&gt;&#xA;Even if it doesn't happen quickly, could the University be destroyed and make me unable to finish my courses?&lt;/p&gt;&#xA;&lt;p&gt;What are the predictions for the next 5 years?  Are the expected changes ones that should make me reconsider my plans to move there there for that time period?&lt;/p&gt;&#xA;" OwnerUserId="28773" LastEditorUserId="6298" LastEditDate="2023-04-05T18:33:58.460" LastActivityDate="2023-04-11T08:39:00.067" Title="Is it safe for me to move to the coast?" Tags="|climate-change|sea-level|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="25076" PostTypeId="1" CreationDate="2023-04-04T08:27:21.080" Score="5" ViewCount="47" Body="&lt;p&gt;What is it about Stages 2,3,4, and 10 (as well as Series 2) in the Cambrian Period that has left solely them unnamed? Will this be resolved in time, or is it a relic of the historical naming process, and is likely to remain fixed?&lt;/p&gt;&#xA;" OwnerUserId="28776" LastActivityDate="2023-04-04T08:27:21.080" Title="Why are there unnamed Cambrian Stages?" Tags="|stratigraphy|geochronology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25077" PostTypeId="1" CreationDate="2023-04-04T14:48:29.020" Score="1" ViewCount="88" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ffJ5X.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ffJ5X.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;Hiking in a field of boulders along a river canyon in Alabama United states.  Sandstone boulders are 20'-30' (6 to 9 meters) tall.  There are perfectly round holes near the top.  I'm wondering what caused these.  I'm interested in the designs but mainly the perfectly round holes.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;" OwnerUserId="28777" LastEditorUserId="28777" LastEditDate="2023-04-04T14:49:08.940" LastActivityDate="2023-04-04T14:49:08.940" Title="How'd this hole get here?" Tags="|geology|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25080" PostTypeId="2" ParentId="18786" CreationDate="2023-04-05T16:57:01.220" Score="0" Body="&lt;p&gt;What is missing from the Q and all the good answers for those new to what Albedo implies.&#xA;Albedo is just Albedo, it cannot map in a linear fashion from one variable to the other.&#xA;It must look at more variables to determine the effect of albedo of a small object amongst large albedo objects.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;The sun the real source, at 6k black body temp.&#xA;This is why it is visible, it is so hot it glows past the far Infra red into the near infra red, and then into the visible, and then and only then if the temp of black body radiator is hot enough UV radiation we cannot see is also emitted.&#xA;Each of these wavelengths from the sun, our primary energy source, interacts with matter differently.&#xA;sometimes it is absorbed, other times it is reflected like a mirror (That is albedo) or it is emitted.&#xA;The earths black body is at 25C, your body black brown or fairer skin radiates at 40C. But we cannot just see it. So it is not intuitive.&#xA;But we know it is true when we get a hug, for example.&#xA;So now it gets more complicated to get the answer.&#xA;One must integrate the radiated, reflected, and absorbed photon band by integrating them at each location of interest.&#xA;Now layer on the fact each blackbody can absorb at one wavelength and emit at another, based on the albedo absorption of the material, yet it will only be able to radiate at its black body radiation energy envelope.&#xA;And layer on top of that more complexity, the surfaces ability to reflect back in some of that black body radiation, even if it cannot be seen, such as IR energy. But the surface is still reflecting some portion of the blackbody temperature in bandwidth or windows.&#xA;The water vapor bands are a good example and place to start. depending on wavelength they can be reflective (high albedo) as in clouds reflecting sunlight. Or it can be also absorptive, and the proportion is changing across wavelengths that all must be integrated in real time.&#xA;At the ground one can model the ground as 1/2 of the radiative directions for my black body radiation interacting with the earths IR radiation, but then also integrate the sky temperature in real time for the other radiative exchange equation.&#xA;My Father Invented Spectrometers his whole life, and I was a good listener. Now an electro-optical-power- engineer&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="28782" LastActivityDate="2023-04-05T16:57:01.220" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25081" PostTypeId="1" CreationDate="2023-04-06T07:32:17.710" Score="1" ViewCount="64" Body="&lt;p&gt;I'm struggling to determine a cloud type on the photo below (I assume it is a Cirrus cloud&#xA;and wind shear also depicted there, correct me if I'm wrong).&#xA;&lt;a href=&quot;https://i.stack.imgur.com/PPY4B.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PPY4B.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28215" LastActivityDate="2023-04-06T07:32:17.710" Title="Determine cloud type on the picture" Tags="|clouds|earth-observation|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25084" PostTypeId="1" AcceptedAnswerId="25090" CreationDate="2023-04-07T19:52:12.897" Score="3" ViewCount="46" Body="&lt;p&gt;Papua New Guinea has many species of snakes, some of which are dangerous:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ecologyasia.com/verts/png-snakes.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ecologyasia.com/verts/png-snakes.htm&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Are any of these species invasive, or are they all indigenous?&lt;/p&gt;&#xA;&lt;p&gt;Or, since that may be a blurry line, let me phrase it more precisely: did any of the snake species of the island, arrive since 1800?&lt;/p&gt;&#xA;" OwnerUserId="7911" LastActivityDate="2023-04-08T14:15:30.203" Title="Are any New Guinea snakes invasive?" Tags="|geography|geobiology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25085" PostTypeId="2" ParentId="18260" CreationDate="2023-04-07T23:28:24.720" Score="2" Body="&lt;p&gt;Imagine you're on a mountain peak with a good view of the horizon all the way around.  Even though the planet is a sphere(-ish), the horizon is on a flat plane that intersects with the edge of your line-of-sight view of the planet as it curves down away from you on all sides. You are actually seeing the curve, as evidenced by the horizon line circling you at a point below your eye level, but you can't really perceive it as anything but a straight line because, even on a mountain peak, you're still too close to the plane of the horizon.  It looks flat, like the vanishing line for an infinite plane.  You have to go really high, higher than a mountain peak to see enough of the horizon in one glance to percieve the curvature with your naked eye and really recognize it as such visually.&lt;/p&gt;&#xA;" OwnerUserId="28791" LastActivityDate="2023-04-07T23:28:24.720" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25086" PostTypeId="2" ParentId="24974" CreationDate="2023-04-08T01:32:44.000" Score="0" Body="&lt;p&gt;I think you are just confusing your self by mixing terminology. stick to east and west not left and right, or even just use 2 axis, with or against spin, and towards or away from the equator (the fastest part).&lt;/p&gt;&#xA;&lt;p&gt;Air moving towards the equator will bend away from the direction of spin. Air moving away from the equator will bend with the direction of spin.&lt;/p&gt;&#xA;&lt;p&gt;Also don't forget you are looking at a circulation not movement in one direction.&lt;/p&gt;&#xA;&lt;p&gt;=&lt;a href=&quot;https://i.stack.imgur.com/tvP6p.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tvP6p.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here are two good video that may help, this is difficult to explain with static images.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=kCbMKSZZO9w&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=kCbMKSZZO9w&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.metoffice.gov.uk/weather/learn-about/weather/atmosphere/global-circulation-patterns&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.metoffice.gov.uk/weather/learn-about/weather/atmosphere/global-circulation-patterns&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2023-04-08T01:47:01.193" LastActivityDate="2023-04-08T01:47:01.193" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25087" PostTypeId="1" CreationDate="2023-04-08T04:50:30.370" Score="3" ViewCount="291" Body="&lt;p&gt;I have some simple seismic traces as shown here. &lt;a href=&quot;https://i.stack.imgur.com/xDEFP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xDEFP.png&quot; alt=&quot;Seismic Gather&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;When attempting to perform a dispersion analysis using the technique described by this &lt;a href=&quot;https://expservices.ku.edu/sites/expservices.drupal.ku.edu/files/docs/1998/Park%20et%20al%20(1998)_Imaging%20dispersion%20curves%20of%20surface%20waves%20on%20multi-channel%20record.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt;, I get the following image.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/L37Pz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/L37Pz.png&quot; alt=&quot;Dispersion Analysis&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Unfortunately, I cannot for the life of me figure out what it is I am doing wrong here. So I feel that I must be missing something conceptually. Below is my python script for processing the dispersion image.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;## . . Perform dispersion analysis&#xA;&#xA;## . . Define parameters&#xA;ng    = 20       # Number of geophones&#xA;nVp   = 200      # Number of Vp test points&#xA;nfreq = 200      # Number of frequency test points&#xA;ndata = 600      # Number of data points per trace&#xA;dt    = 1/16000  # Time_Delta&#xA;&#xA;## . . Define gridspace&#xA;freq = np.linspace(0, 40, nfreq)  # Frequency spectrum (Hz)    &#xA;Vp   = np.linspace(1, 500, nVp)   # Phase velocity spectrum (m/s)&#xA;X, Y = np.meshgrid(freq, Vp)&#xA;&#xA;## . . Setup gridspace for the slant stack function&#xA;S = np.zeros((ng, nfreq, nVp, ndata), dtype=complex)&#xA;&#xA;## . . Calculate dispersion with varying phase velocity and frequency&#xA;for idx, trace in enumerate(seismic_gather[0].trace):&#xA;  ## Get the fourier transformation and normalization of the waveform&#xA;  U = np.fft.fft(trace.data)  # Fourier transform &#xA;  N = U/np.abs(U)             # Normalize waveform&#xA;&#xA;  ## Apply dynamic linear moveout&#xA;  P = 2*np.pi*X*trace.offset/Y             # Dispersion property&#xA;  S[idx] = np.exp(1j*P)[:,:,np.newaxis]*N&#xA;&#xA;  &#xA;## . . Stack traces&#xA;S = np.sum(S, 0)&#xA;&#xA;## . . Extract amplitudes&#xA;A = np.abs(S)/ng&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;To describe the code a little, I am defining a meshgrid space of 200 testing points for the Phase Velocity and Frequency. I then take my seismic data and transform it into the frequency domain and normalize it. Once normalized, I apply the dynamic linear moveout to each trace, and then stack the the traces for each pair of phase velocity and frequency points along the meshgrid.&lt;/p&gt;&#xA;&lt;p&gt;Unfortunately, the resulting image doesn't appear to be what I expect, which I expect to be similar to the paper linked. Am I missing a step here?&lt;/p&gt;&#xA;" OwnerUserId="28792" LastEditorUserId="543" LastEditDate="2023-04-08T17:17:46.600" LastActivityDate="2024-01-26T16:04:30.570" Title="I am trying to write a simple python script for dispersion analysis of surface waves, but I think I am missing something conceptually" Tags="|geophysics|python|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25088" PostTypeId="1" AcceptedAnswerId="25089" CreationDate="2023-04-08T06:21:49.697" Score="4" ViewCount="427" Body="&lt;p&gt;Generally speaking, iron is considered to be a very common resource. But I cannot find any evidence that there is any of it at all in New Guinea. &lt;a href=&quot;https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1751-3928.2005.tb00249.x&quot; rel=&quot;noreferrer&quot;&gt;Copper and gold, yes.&lt;/a&gt; Even nickel and cobalt. &lt;a href=&quot;https://www.reuters.com/article/us-papua-mining-idUSKBN17Y05E&quot; rel=&quot;noreferrer&quot;&gt;Iron on the nearby island of Bougainville.&lt;/a&gt; But no mention of iron.&lt;/p&gt;&#xA;&lt;p&gt;Are there really no useful iron deposits on the entire island? Or is it more like, there are some, just not big enough to make the news?&lt;/p&gt;&#xA;" OwnerUserId="7911" LastActivityDate="2023-11-11T10:02:31.130" Title="Is there any iron ore in New Guinea?" Tags="|minerals|mining|economic-geology|iron|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25089" PostTypeId="2" ParentId="25088" CreationDate="2023-04-08T10:05:46.160" Score="4" Body="&lt;p&gt;The island of New Guinea is effectively divided into two entities, the country of Papua New Guinea occupies the eastern half and the Indonesian province of West New Guinea occupies the western half.&lt;/p&gt;&#xA;&lt;p&gt;No known &lt;strong&gt;hard rock deposits&lt;/strong&gt; of iron ore have been reported for anywhere on the island.&lt;/p&gt;&#xA;&lt;p&gt;In Indonesia, as of 2020, the &lt;a href=&quot;https://www.mining-technology.com/marketdata/five-largest-iron-ore-mines-indonesia-2020/&quot; rel=&quot;noreferrer&quot;&gt;top five iron ore mines&lt;/a&gt; are:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Yiwan Mine&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;The Yiwan Mine is located in South Kalimantan. It is owned by Yiwan Mining.The mine produced an estimated 2.547 MTPA of iron ore in 2020.&lt;/p&gt;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;Gag Island Project&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Located in West Papua, the Gag Island Project is owned by Indonesia Asahan Aluminium. The surface mine produced an estimated 1.06 MTPA of iron ore in 2020. The mine will operate until 2047.&lt;/p&gt;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;Pomalaa Mine&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;The Pomalaa Mine is located in South East Sulawesi. It is owned by Indonesia Asahan Aluminium and produced an estimated 0.943 MTPA of iron ore in 2020.&lt;/p&gt;&#xA;&lt;ol start=&quot;4&quot;&gt;&#xA;&lt;li&gt;Pakal Island Mine&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;The Pakal Island Mine, owned by Indonesia Asahan Aluminium, is a surface mine located in North Maluku. The mine produced an estimated 0.515 MTPA of iron ore in 2020.&lt;/p&gt;&#xA;&lt;ol start=&quot;5&quot;&gt;&#xA;&lt;li&gt;Nalo Baru Mine&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Owned by Earthstone Holdings, the Nalo Baru Mine is a surface mine located in Jambi. It produced an estimated 0.027 MTPA of iron ore in 2020. The mine will operate until 2031.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;As you state in our question, there a small number of hard rock deposits on smaller islands that are part of Papua New Guinea.&lt;/p&gt;&#xA;&lt;p&gt;The only iron ore resource that occurs on the island of New Guinea are deposits of &lt;a href=&quot;https://mine.onepng.com/2021/11/pngs-orokolo-by-iron-sand-project.html&quot; rel=&quot;noreferrer&quot;&gt;iron sands&lt;/a&gt;. They lie on the &lt;a href=&quot;https://mayurresources.com/minerals/&quot; rel=&quot;noreferrer&quot;&gt;southern coast of PNG&lt;/a&gt;, around the coast of the Gulf of Papua. Currently, the main deposits are at Amazon Bay in the south east and Orokolo at the top of the gulf.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1NJB1.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1NJB1.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It appears the iron sands are associated with other mineral sand minerals that are zircon rich, with some deposits having titanium and others vanadium. The iron sands are composed of &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnetite&quot; rel=&quot;noreferrer&quot;&gt;magnetite&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-04-08T10:05:46.160" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25090" PostTypeId="2" ParentId="25084" CreationDate="2023-04-08T14:06:50.457" Score="3" Body="&lt;p&gt;No. None of the species we currently consider invasive on Papua New Guinea are reptiles.&lt;/p&gt;&#xA;&lt;p&gt;A web site &lt;a href=&quot;https://www.gbif.org/occurrence/search?dataset_key=a38c7d49-5a5d-4aa6-a64e-421178bd06d7&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; has a &lt;a href=&quot;https://www.gbif.org/dataset/a38c7d49-5a5d-4aa6-a64e-421178bd06d7&quot; rel=&quot;nofollow noreferrer&quot;&gt;dataset which lists 51 invasive species&lt;/a&gt; for that location. Of the 3 species in the phylum &lt;a href=&quot;https://en.wikipedia.org/wiki/Chordate&quot; rel=&quot;nofollow noreferrer&quot;&gt;chordata&lt;/a&gt;, 2 are mammals and 1 is a bird. (This is the taxonomic breakdown)&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Plantae 22&lt;/li&gt;&#xA;&lt;li&gt;Animalia 19&lt;/li&gt;&#xA;&lt;li&gt;Arthropoda 14&lt;/li&gt;&#xA;&lt;li&gt;Chordata 3&lt;/li&gt;&#xA;&lt;li&gt;&#xA;&lt;pre&gt;&lt;code&gt; Mammalia 2 &#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&#xA;&lt;pre&gt;&lt;code&gt; Aves 1&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;Nematoda 1&lt;/li&gt;&#xA;&lt;li&gt;Unknown phylum 1&lt;/li&gt;&#xA;&lt;li&gt;Bacteria 4&lt;/li&gt;&#xA;&lt;li&gt;incertae sedis 3&lt;/li&gt;&#xA;&lt;li&gt;Fungi 2&lt;/li&gt;&#xA;&lt;li&gt;Chromista 1&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;No reptiles, so no snakes are considered invasive species.&lt;/p&gt;&#xA;" OwnerUserId="6057" LastEditorUserId="6057" LastEditDate="2023-04-08T14:15:30.203" LastActivityDate="2023-04-08T14:15:30.203" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25092" PostTypeId="1" CreationDate="2023-04-09T09:56:52.933" Score="2" ViewCount="70" Body="&lt;p&gt;Of the major cloud families, the &amp;quot;&lt;a href=&quot;https://cloudatlas.wmo.int/en/cumulus-cu.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;cumulus&lt;/a&gt;&amp;quot; type (including stratocumulus, altocumulus and so on) are generally formed by convection in unstable air, leading to their &amp;quot;lumpy&amp;quot; or &amp;quot;heap-like&amp;quot; forms.  The &lt;a href=&quot;https://cloudatlas.wmo.int/en/stratus-st.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stratus&lt;/a&gt; clouds, form in stable air, by advection (a layer of stratus or altostratus in advance of a warm front), or direct radiative cooling (fog). The absence of convection results in their layered form.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://cloudatlas.wmo.int/en/species-altocumulus-lenticularis-ac-len.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Altocumulus lenticularis&lt;/a&gt; does not seem to fit this pattern.  It develops in stable air, that is being forced to rise perhaps as a result of upwind topography. Unlike other cumulus clouds, the flow of air remains laminar and not turbulent. There is no convection within the cloud, and the only reason that an extended layer of cloud doesn't form is that downwind the air descends, again as a result of the landforms.  Lenticularis clouds are known to remain in one place and not move with the wind.&lt;/p&gt;&#xA;&lt;p&gt;Lenticular clouds are often similar to &lt;a href=&quot;https://www.weatheronline.co.uk/reports/wxfacts/Cap-cloud.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;cap clouds and pileus, which are classified as stratiform clouds&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;So, is convection a defining factor for clouds to be classified as &amp;quot;cumulus&amp;quot; or &amp;quot;Altocumulus&amp;quot;?   Is the classification of Lenticularis clouds as a species of Altocumulus based mainly on historical precedent, rather than consideration of their mode of formation?&lt;/p&gt;&#xA;" OwnerUserId="9563" LastActivityDate="2023-04-09T09:56:52.933" Title="Altocumulus lenticularis - Why is this not considered a &quot;strati-form type cloud" Tags="|meteorology|clouds|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25093" PostTypeId="1" CreationDate="2023-04-10T09:38:33.053" Score="4" ViewCount="195" Body="&lt;p&gt;Since 1945 &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_nuclear_weapons_tests&quot; rel=&quot;nofollow noreferrer&quot;&gt;2476&lt;/a&gt;  nuclear bombs were exploded on this planet during tests with a total yield of 545 megatons. The &lt;a href=&quot;https://www.armscontrol.org/factsheets/nucleartesttally&quot; rel=&quot;nofollow noreferrer&quot;&gt;peak of testing&lt;/a&gt; took place in the late 50's and early 60's with 116 bombs exploded in 1958 and 178 bombs exploded in 1962 and in 1961 the USSR detonated an hydrogen bomb (&lt;a href=&quot;https://en.wikipedia.org/wiki/Tsar_Bomba&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tsar Bomba&lt;/a&gt;) with a yield of at least 50 megatons.&lt;/p&gt;&#xA;&lt;p&gt;The article at this &lt;a href=&quot;https://www.pnas.org/doi/10.1073/pnas.0710058105&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt; states that a regional nuclear war involving 100 Hiroshima-size bombs (totaling 1.5 megaton)  would cause a significant depletion of the ozone layer.&#xA;This other &lt;a href=&quot;https://www.authorea.com/users/519642/articles/593292-underground-nuclear-testing-the-leading-cause-of-global-warming#:%7E:text=The%20derivative%20carbon%20footprint%20of,Leading%20Cause%20of%20Global%20Warming.&quot; rel=&quot;nofollow noreferrer&quot;&gt;paper&lt;/a&gt; claims that the derivative carbon footprint of underground nuclear testing is colossal.&lt;/p&gt;&#xA;&lt;p&gt;Because I know very little about the subject and because there may be many more results proving or disproving the implications of nuclear test on climate change and ozone layer depletion, I would like to ask for some more explanations and some references.&lt;/p&gt;&#xA;" OwnerUserId="27059" LastEditorUserId="27059" LastEditDate="2023-04-10T21:39:43.613" LastActivityDate="2023-04-10T21:39:43.613" Title="What was the impact of nuclear tests on climate change and ozone layer depletion?" Tags="|climate-change|ozone|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="25094" PostTypeId="1" CreationDate="2023-04-10T21:51:11.827" Score="1" ViewCount="58" Body="&lt;p&gt;I want to download Vertical Velocity (Pa/sec) data either in era interim or NCAR data from a website. Please I need the link.&lt;/p&gt;&#xA;" OwnerUserId="28799" LastEditorUserId="2470" LastEditDate="2023-04-11T00:46:24.737" LastActivityDate="2023-05-11T06:05:50.750" Title="From where can I download NCEP Vertical wind?" Tags="|atmosphere|wind|earth-observation|reanalysis|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25095" PostTypeId="1" CreationDate="2023-04-10T23:01:31.513" Score="2" ViewCount="124" Body="&lt;p&gt;I'm currently in university for environmental science, and in a lecture on paleoclimate our professor showed some graphs of climate in the Holocene and Pleistocene periods (included below), then remarked that the Holocene is much more stable in temperature than the Pleistocene, and then carried out without elaborating.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nOjz4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nOjz4.png&quot; alt=&quot;Graph of temperature averages during the Pleistocene and Holocene periods. &quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Do we know why this is the case? Has there been any research trying to find out why this is?&lt;/p&gt;&#xA;" OwnerUserId="28800" LastEditorUserId="2470" LastEditDate="2023-04-11T00:44:41.597" LastActivityDate="2023-04-19T11:17:26.993" Title="Why is it that the Holocene's temperature is much more stable than the Pleistocene?" Tags="|climate|paleoclimatology|climatology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25096" PostTypeId="1" AcceptedAnswerId="25106" CreationDate="2023-04-11T05:37:33.637" Score="2" ViewCount="112" Body="&lt;p&gt;In meteorology, we know that cold air mass sinks while warm air mass rises due to density difference, resulting in higher pressure in cold air mass. This leads to a horizontal pressure gradient from cold to warm area (i.e. wind flows from cold to warm area).&lt;/p&gt;&#xA;&lt;p&gt;However, when considering the situation for thermal wind, based on the hypsometric equation, at any same level, the pressure over cold area is lower than that over warm area, resulting in horizontal pressure gradient from warm to cold area. This is the reverse of the above situation, which is confusing. How do we explain the difference between the two situations to eliminate any contradiction?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1rRhr.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1rRhr.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28801" LastEditorUserId="28801" LastEditDate="2023-04-12T04:50:01.323" LastActivityDate="2023-04-12T15:13:56.127" Title="Confusion with thermal wind mechanism" Tags="|meteorology|atmosphere|wind|barometric-pressure|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25097" PostTypeId="2" ParentId="25094" CreationDate="2023-04-11T05:51:16.510" Score="1" Body="&lt;p&gt;The variable for vertical velocity in NCEP-NCAR is omega, dp/dt or change of pressure with time. Go to &lt;a href=&quot;https://psl.noaa.gov/data/gridded/data.ncep.reanalysis.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://psl.noaa.gov/data/gridded/data.ncep.reanalysis.html&lt;/a&gt; and type &amp;quot;omega&amp;quot; in the search variable field to look for the specific time resolution data you want to download.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/K3cq8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/K3cq8.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28801" LastActivityDate="2023-04-11T05:51:16.510" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25099" PostTypeId="2" ParentId="25075" CreationDate="2023-04-11T08:39:00.067" Score="7" Body="&lt;p&gt;Sea Level Rise owing to &lt;a href=&quot;https://climate.nasa.gov/vital-signs/global-temperature/&quot; rel=&quot;noreferrer&quot;&gt;climate change&lt;/a&gt; is happening. But relative to human life spans, and the length of a study course, it is very slow.&lt;/p&gt;&#xA;&lt;p&gt;Waves from storms could be a problem, but the school is reasonably well protected within Guanabara Bay.&lt;/p&gt;&#xA;&lt;p&gt;Storm surge could be a problem, if wind directions, and tides align. But you could reduce this risk my signing up for weather warnings.&lt;/p&gt;&#xA;&lt;p&gt;During heavy rain, you may find that surface water can flow down streets etc. which can be dangerous is short term. This could happen anywhere though.&lt;/p&gt;&#xA;&lt;p&gt;In most coastal cities it would be very rare to have flooding over 5 meters in depth. If you are worried perhaps pick accomodation on 2nd floor, or above. But really this is just for peace of mind.&lt;/p&gt;&#xA;&lt;p&gt;Go study &amp;amp; have fun.&lt;/p&gt;&#xA;" OwnerUserId="28802" LastActivityDate="2023-04-11T08:39:00.067" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25100" PostTypeId="2" ParentId="25096" CreationDate="2023-04-11T12:21:43.307" Score="0" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;we know that cold air mass sinks while warm air mass rises due to&#xA;density difference, resulting in higher pressure in cold air mass&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Wrong. Only hot &lt;strong&gt;enough&lt;/strong&gt; air rises, not all hot air. It's hot enough when the entropy/potential temperature profile has a negative slope w.r.t altitude.&lt;/p&gt;&#xA;&lt;p&gt;Your pressure in the cold region is lower than in the hot region, same as for the thermal wind. But this is due to different balancing requirements (vertical vs horizontal), so you're not comparing apples to apples here.&lt;/p&gt;&#xA;" OwnerUserId="489" LastActivityDate="2023-04-11T12:21:43.307" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25102" PostTypeId="1" CreationDate="2023-04-11T19:22:56.440" Score="1" ViewCount="65" Body="&lt;p&gt;[ ~/Desktop/demo ] $ segyread tape=data.sgy| segyclean&amp;gt;data.su&lt;/p&gt;&#xA;&lt;p&gt;segyread: format not SEGY standard (1, 2, 3, 5, or 8)&lt;/p&gt;&#xA;&lt;p&gt;segyclean: fgettr.c: bad first header&#xA;[ ~/Desktop/demo ] $ 3200+0 records in&#xA;6+1 records out&#xA;3200 bytes (3.2 kB) copied, 0.00177647 s, 1.8 MB/s&lt;/p&gt;&#xA;" OwnerUserId="28806" LastActivityDate="2023-04-11T19:22:56.440" Title="I got this error (segyread: format not SEGY standard (1, 2, 3, 5, or 8)) while converting from segy to su format on seismic unix" Tags="|geophysics|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25103" PostTypeId="1" AcceptedAnswerId="25104" CreationDate="2023-04-12T06:47:48.803" Score="5" ViewCount="190" Body="&lt;p&gt;I was taught that while the motion of a tropical cyclone is mostly cyclonic, there is an outflow at the top whose motion is anticyclonic. So I expected an animated satellite image of a typhoon to look like a spiral spinning clockwise. However, it appeared to spin counterclockwise(&lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Satellite_GIF_of_Typhoon_Trami_Himawari_Satellite.gif&quot; rel=&quot;noreferrer&quot;&gt;Example&lt;/a&gt;). Why is that? Is it because the clouds generated by the outflow are too thin that they are not visible in the satellite image, even in the infrared image?&lt;/p&gt;&#xA;" OwnerUserId="22031" LastActivityDate="2023-04-13T17:25:23.383" Title="The motion of the upper-level outflow of a typhoon" Tags="|tropical-cyclone|weather-satellites|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25104" PostTypeId="2" ParentId="25103" CreationDate="2023-04-12T11:01:29.223" Score="3" Body="&lt;p&gt;It's hard to see but it's definitely there in your example. You can see some upper-level clouds in the South-Southeast quadrant of the storm moving away from the center in somewhat of an anticyclonic manner. There's also some upper-level clouds at the left most part of the animation that are also migrating away from the storm center.&lt;/p&gt;&#xA;&lt;p&gt;But yes, sometimes the clouds are too thin that they are barely visible even in infrared imagery. I suggest you to take a look at a real-time wind map online where you can vary the altitude, such as Windy. Here, you'll be able to clearly see the outflow of a tropical cyclone at a certain height. The anticyclonic outflow of a tropical cyclone is much more noticeable at stronger intensities so you may have to wait for a big storm to show up.&lt;/p&gt;&#xA;" OwnerUserId="28809" LastActivityDate="2023-04-12T11:01:29.223" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25105" PostTypeId="1" AcceptedAnswerId="25123" CreationDate="2023-04-12T12:16:47.107" Score="4" ViewCount="104" Body="&lt;p&gt;Fractional crystallisation generally makes magma more silicic. Why was a substantial quartz layer not a product of the stratification of the Lunar mantle?&lt;/p&gt;&#xA;" OwnerUserId="27711" LastActivityDate="2023-04-21T14:01:32.960" Title="Why was quartz not a major product of the Lunar Magma Ocean?" Tags="|planetary-science|petrology|mantle|moon|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25106" PostTypeId="2" ParentId="25096" CreationDate="2023-04-12T14:47:01.340" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;based on the hypsometric equation, at any same level, the pressure&#xA;over cold area is lower than that over warm area, resulting in&#xA;horizontal pressure gradient from warm to cold area.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Not necessarily. In a colder area, the isobars are more &amp;quot;compressed&amp;quot; while in a warmer area, the isobars are more &amp;quot;spread out&amp;quot;. In most examples of thermal wind, the pressure at the surface is actually the same in the cold area and in the warm area. Take a look at &lt;a href=&quot;http://www-das.uwyo.edu/%7Egeerts/cwx/notes/chap12/Image82.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; image. The horizontal pressure gradient is only up in the higher altitudes. As a matter of fact, thermal wind is greater in the upper troposphere and weakens closer to the surface.&lt;/p&gt;&#xA;&lt;p&gt;Does this contradict the concept of monsoons? No because monsoons are surface-level winds. Let's use land and sea breezes as an example since they are basically just small-scale monsoons. Take a look at &lt;a href=&quot;https://www.weather.gov/source/zhu/ZHU_Training_Page/winds/Wx_Terms/sea_breeze.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; image regarding land and sea breezes.  Air in the warm region rises which causes the isobars to &amp;quot;spread apart&amp;quot;. A horizontal pressure gradient in the upper troposphere occurs so wind will flow from the warm area to the cooler area; this is thermal wind. Air above the cooler area sinks because it is more dense. This gives room for the thermal wind to also sink above the cooler area. The surface pressure in the cooler area is now higher than the warmer area since the sinking air is building up. A horizontal pressure gradient forms which causes wind on the surface to flow from the cooler area to the warmer area.&lt;/p&gt;&#xA;&lt;p&gt;I hope you understand since explaining this was a bit tricky without a lot of visualization. Also, check out wind flow maps of a monsoon. On the surface, wind flows from the colder area to the hotter area. But if you check the wind flow at higher altitudes, the wind actually reverses.&lt;/p&gt;&#xA;&lt;p&gt;Edit: Here's an analogy I just thought of. Think of the air as individual molecules. Think of these molecules as balls in an aquarium. These balls would always want to be a set distance away from other balls. If a ball is too near to another ball, they will push each other; if a ball is too far from another ball, they will try to go closer.&lt;/p&gt;&#xA;&lt;p&gt;One end of the aquarium is hot while the other is cold. The balls in the hot part rise and build up at the upper portion of the aquarium. The balls in the cold part sink and build up at the bottom part of the aquarium. The balls build up but since they don't want to be together, they flow towards the spaces with no balls. The hot balls will glide on the ceiling of the aquarium towards the colder part where they cool down and sink. The cold balls will glide on the floor of the aquarium towards the hot part where they heat up and rise. The cycle then just keeps repeating.&lt;/p&gt;&#xA;&lt;p&gt;The thermal wind phenomenon occurs on the ceiling of the aquarium, the monsoon/land-sea breeze phenomenon occurs on the floor of the aquarium.&lt;/p&gt;&#xA;" OwnerUserId="28809" LastEditorUserId="28809" LastEditDate="2023-04-12T15:13:56.127" LastActivityDate="2023-04-12T15:13:56.127" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25107" PostTypeId="2" ParentId="25103" CreationDate="2023-04-13T04:59:32.310" Score="1" Body="&lt;p&gt;Thing is:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The high pressure tends to be relatively weak in comparison to the low-level cyclone, such that winds are much weaker around the high aloft than around the low nearer the ground. &lt;sub&gt;&lt;sup&gt;(by strength, I'm talking about relative to surrounding or typical pressures/heights at the same level, so how abnormal a value it is/how strong the pressure gradient is)&lt;/sup&gt;&lt;/sub&gt;&lt;/li&gt;&#xA;&lt;li&gt;The vigorous convection of a hurricane/typhoon is forced at lower levels... so all the cumulus you see be transitioning in the cyclonic pattern following the low-level forcing.&lt;/li&gt;&#xA;&lt;li&gt;So because of this, and because the upper level clouds are typically thinner cirrus, you'll have to find blowoff from storms which move away so that they are not above the cumulus... combine this in with the fact that winds tend to increase with distance away from high pressure, while decreasing with distance from the low pressure (a factor of the way the pressure gradient distributions that develop... with a relatively wide and broad high, versus and sharp and tight low)... all that together means that the anticyclone will only typically tend to be noticeable at significant distance from the storm (and will still yet tend to rotate much more slowly than the significant storms in the inner core).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;And to throw in one more challenge... the cirrus you'll need to track don't show as well at visible wavelengths, so if you happen to be looking at visible imagery, especially during midday, you may further struggle to see any anticyclone aloft.&lt;/p&gt;&#xA;&lt;p&gt;So all you have to do is look away from the more interesting part of the storm, for features much less numerous (because the cirrus isn't usually a widespread feature, not forming much on its own, but only from the main storm blowoff), things are moving much less, and be looking at the right type of satellite imagery!&lt;/p&gt;&#xA;&lt;p&gt;But it's more than possible.  A neat one to me is &lt;a href=&quot;https://www.youtube.com/watch?v=dnWNOudrtC0&quot; rel=&quot;nofollow noreferrer&quot;&gt;this multi-day animation of Hurricane Irma from 2017&lt;/a&gt; &lt;sub&gt;&lt;sup&gt;(and Katia and especially Jose too!)&lt;/sup&gt;&lt;/sub&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Or, we're in luck a bit datawise right now, if we can handle a key difference, with Cyclone &lt;a href=&quot;https://en.wikipedia.org/wiki/Cyclone_Ilsa&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ilsa&lt;/a&gt; nearing &lt;a href=&quot;http://www.bom.gov.au/cyclone/index.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;northwest Australia as a category 4 Tropical Cyclone&lt;/a&gt; &lt;sup&gt;&lt;sub&gt;(cyclone is basically the Australian term for a typhoon [or really supertyphoon], also similar to the Western Hemisphere term hurricane) &lt;/sub&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;So some images:&lt;br /&gt;&#xA;(But just remember, rotation is opposite in the southern hemisphere, so low pressure rotates clockwise and high pressure counterclockwise)&lt;/p&gt;&#xA;&lt;p&gt;Here is the infrared satellite imagery of Ilsa from CIMSS &lt;a href=&quot;http://tropic.ssec.wisc.edu/real-time/storm.php?&amp;amp;basin=austwest&amp;amp;sname=18S&amp;amp;invest=NO&amp;amp;zoom=4&amp;amp;img=1&amp;amp;vars=11111000000000000000&amp;amp;loop=0&amp;amp;llval=OFF&quot; rel=&quot;nofollow noreferrer&quot;&gt; [click here for the current animation&lt;/a&gt;] where the anticyclone is findable:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Z5w79.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Z5w79.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;To help, I turned on the cyan wind barbs, which are actually from an algorithm tracking the upper level cloud elements in the imagery [determined by using an algorithm on cloud temperatures I believe, then tracking which way the features move] [the cyan is between 100 and 250 mb, the yellow is between 250 and 350 mb, and the green is between 350 mb and 500 mb]&lt;/p&gt;&#xA;&lt;p&gt;And then, here is a current global model analysis (from &lt;a href=&quot;https://www.weathernerds.org/models/gfs.html?&amp;amp;inittype=zoom&amp;amp;initfield=Winds_250_mb&amp;amp;initcycle=determine&amp;amp;initfhour=000&amp;amp;initimdimx=1050&amp;amp;initimdimy=750&amp;amp;initrange=-2.857142857140:98.742857142600:-30.571428571380:137.485714285440&amp;amp;initcx1=293&amp;amp;initcy1=330&amp;amp;initcx2=396&amp;amp;initcy2=417&amp;amp;initcross=False&amp;amp;initsound=False&amp;amp;initsoundx=288&amp;amp;initsoundy=325&amp;amp;initloop=False&amp;amp;initoverlay=True&amp;amp;initlstart=000&amp;amp;initlend=384&amp;amp;initlint=6&amp;amp;initol1=Winds_10m&amp;amp;initol2=Winds_250_mb&amp;amp;initol3=Winds_250_mb&amp;amp;initol4=null&amp;amp;initol5=null&amp;amp;initcities=On&amp;amp;inithgwys=On&amp;amp;initunits=On&amp;amp;initlatlon=Off&quot; rel=&quot;nofollow noreferrer&quot;&gt;WeatherNerds.net&lt;/a&gt;) which allows us to see the full atmospheric motion, overlaying the low level winds (the black symbols, flowing towards the side of the symbol with no additional sticks/addons)) and the upper level winds (the dark blue symbols, again flowing towards the side of the symbol with no additional sticks/addons):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/remMo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/remMo.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The purple arrow follows the blue symbols, showing the [counter-clockwise, since Southern Hem] upper-level anticyclone (high pressure), and the grey arrow follows the black symbols, showing the [clockwise, since Southern Hem] low-level cyclone (low pressure).  [If you &lt;a href=&quot;https://www.weather.gov/hfo/windbarbinfo&quot; rel=&quot;nofollow noreferrer&quot;&gt;know how to read station obs&lt;/a&gt;, note in either imagery how the upper winds are quite weak compared to the roughly 130 kt-equivalent-typhoon speed &lt;sub&gt;&lt;sup&gt;&lt;a href=&quot;https://www.air-worldwide.com/publications/air-currents/2014/Which-Wind-Speed-/&quot; rel=&quot;nofollow noreferrer&quot;&gt;[VERY ROUGHLY&lt;/a&gt;... as converting wind speeds between cyclones/typhoons/hurricanes/ground observations is a &lt;a href=&quot;https://library.wmo.int/doc_num.php?explnum_id=290&quot; rel=&quot;nofollow noreferrer&quot;&gt;FAR too complex subject]&lt;/a&gt;&lt;/sup&gt;&lt;/sub&gt;]&lt;/p&gt;&#xA;&lt;p&gt;So they're there, you just may have to look carefully.&lt;br /&gt;&#xA;Typically the stronger the tropical cyclone [tropical cyclone is a generic term for typhoons/cyclones/hurricanes/etc], the stronger the high pressure, because &lt;a href=&quot;https://wx.erau.edu/faculty/mullerb/Wx365/Hurricanes/hurricanes.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;the anticyclone grows as the heat is released aloft near the center of the storm&lt;/a&gt;.  Though there can be a bit of a chicken-egg factor sometimes... a larger, more stacked existing anticyclone itself can help strengthen a storm in the first place due to the reduced wind shear.  And I suppose you also can get a leftover strongish anticyclone over a suddenly rapidly-dying tropical cyclone (if it moves over significant land/cold water).&lt;/p&gt;&#xA;&lt;p&gt;I've also noticed that often there's more debris clouds helping to see the nearby anticyclone (note these aren't really the same as the large regional features like the Bermuda high or Pacific High, which are a whole separate, much larger scale; the Bermuda High typically covers most of the Atlantic, far north of most storms, typically steering hurricanes from west to east) on the poleward side of a tropical cyclone.  This makes sense, as that is the side where the convection will interact with the mid-latitude winds aloft, which are much faster, and also where the moisture can help fuel additional cloudiness due to the more baroclinic environment.  Such outflow channels can be important in the intensification of tropical cyclones.  Or other times, they foreshadow a storm becoming extratropical.  &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Ian_2022-09-28_1441Z.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's&lt;/a&gt; a great example of such elongated outflow from Hurricane Ian last year:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZCvpZ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZCvpZ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;You may be able to almost visualize the slow clockwise rotation around the northeast side of the storm just in that still image?  (If not, &lt;a href=&quot;https://satlib.cira.colostate.edu/event/hurricane-ian/&quot; rel=&quot;nofollow noreferrer&quot;&gt;try the loop titled Hurricane Ian Approaches Florida loop, well down this page&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;So some imagery lends itself better to finding the local anticyclone about a tropical cyclone, but they're generally there.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2023-04-13T17:25:23.383" LastActivityDate="2023-04-13T17:25:23.383" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25108" PostTypeId="1" CreationDate="2023-04-14T09:01:07.783" Score="1" ViewCount="39" Body="&lt;p&gt;I wonder if the southern downwelling situation in the AMOC is affected by climate change as much as the two northern situations. I come to the question because I find the Cicrumantarctic circulation climatically isolates this region and I have read in various papers like: Interbasin and interhemispheric impacts of a collapsed Atlantic Overturning Circulation that the northern downwelling situations are failing due to climate change.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rpw3b.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rpw3b.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://de.wikipedia.org/wiki/Thermohaline_Zirkulation#/media/Datei:Thermohaline_Circulation.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://de.wikipedia.org/wiki/Thermohaline_Zirkulation#/media/Datei:Thermohaline_Circulation.svg&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;In the figure that shows a simplified situation of the AMOC, the three downwelling situations I am talking about are clearly visible&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="18081" LastEditDate="2023-07-26T20:15:32.247" LastActivityDate="2023-07-26T20:15:32.247" Title="Is the southern downwelling situation in the AMOC as affected by climate change as the two northern downwelling situations?" Tags="|oceanography|thermohaline-circulation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25109" PostTypeId="1" AcceptedAnswerId="25121" CreationDate="2023-04-14T13:10:57.763" Score="3" ViewCount="77" Body="&lt;p&gt;Glaciers flow as they deform under its own weight. But they also advance or retreat accordingly to the various climate factors.&lt;/p&gt;&#xA;&lt;p&gt;How would I differentiate a glacier that is in motion flowing down the valley because of its dynamic property from a glacier that is responding to the climate change?&lt;/p&gt;&#xA;" OwnerUserId="28184" LastEditorUserId="2470" LastEditDate="2023-04-15T04:40:41.563" LastActivityDate="2023-04-23T12:51:24.877" Title="Why would glaciers change its size? How to differenciate change in glacier size as a response to climate and its natural dynamics?" Tags="|climate-change|glaciology|geomorphology|glaciation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25110" PostTypeId="1" CreationDate="2023-04-14T21:07:15.027" Score="2" ViewCount="142" Body="&lt;p&gt;In the paper &amp;quot;&lt;a href=&quot;http://hharde.de/index_htm_files/Harde-Schnell-GHE-m.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Experimental Verification of the Greenhouse Effect&lt;/a&gt;&amp;quot; (full version: &amp;quot;&lt;a href=&quot;https://scienceofclimatechange.org/wp-content/uploads/Harde-Schnell-2022-Verification-GHE-Experiment.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Verification of the Greenhouse Effect in the Laboratory&lt;/a&gt;&amp;quot;, Hermann Harde, Michael Schnell 2022), the authors describe an experimental setup that demonstrates the atmospheric greenhouse effect.&lt;/p&gt;&#xA;&lt;p&gt;The experimental setup is as follows (from the paper):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aHKxO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aHKxO.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;For our studies we use an experimental set-up, which consists of two plates in a closed housing, one plate heated to 30°C, the other cooled to -11.4°C (Fig. 1). The plates have a distance of 1.11m to each other, and the tank can be filled with different gases to study the radiation transfer between the plates in the presence of the GH-gases.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;They found that when keeping the energy input to the Earth plate constant, and adding IR-active gases such as CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;, the temperature of the Earth plate increases due to the back-radiation effect:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YVzWi.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YVzWi.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(Note: the &amp;quot;Reduced Heating&amp;quot; section at the end is when they decrease the energy input to the Earth-plate until it gets back to 30°C; the difference in energy input is used to calculate the magnitude of the back-radiation effect.)&lt;/p&gt;&#xA;&lt;p&gt;My question is: why did the addition of the IR-interacting gas not result in any increase in air temperature (denoted by T1, T2, T3, and T4)?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;My understanding is that the IR-active gas (say, CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt;) interacts with the infrared light emitted by the Earth plate, by absorbing it, which causes the CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; molecules to vibrate. This is described as it heating up, for example (emphasis in the original):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;When photons bump into other atoms, some of their energy can get the electrons in those atoms &lt;em&gt;&lt;strong&gt;resonating&lt;/strong&gt;&lt;/em&gt; or moving faster than they were before - that’s what we call &lt;em&gt;&lt;strong&gt;heat&lt;/strong&gt;&lt;/em&gt;. The properties of these molecules and their bonds determine if a gas in the atmosphere will absorb infrared radiation or not. [&lt;a href=&quot;https://gml.noaa.gov/education/info_activities/pdfs/LA_whats_so_special_about_co2.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Then the CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; spontaneously re-emits infrared light of the same wavelength, but this time in a random spherical direction. Some of it is emitted back to the Earth plate which is what results in its higher temperature.&lt;/p&gt;&#xA;&lt;p&gt;However, between the period of absorption and emission, the CO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; is vibrating more -- shouldn't this mean it has more kinetic energy? And as 10% of the air (in this trial) now has more kinetic energy for a constant amount of the time -- shouldn't that directly translate in a higher air temperature?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;For another example with a different explanation (emphasis in the original):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Once the atmosphere is absorbing radiation something has to happen. [...] energy absorbed has to go somewhere and and in this case the energy goes into increased heat of that section of the atmosphere, as we saw in Part Two of this series.&lt;/p&gt;&#xA;&lt;p&gt;In general, and especially true in the troposphere (the lower part of the atmosphere up to around 10km), the increased energy of a molecule of CO2 (or water vapor, CH4, etc) heats up the molecules around it – &lt;strong&gt;and that section of the atmosphere then radiates out energy&lt;/strong&gt;, both up and down. [&lt;a href=&quot;https://scienceofdoom.com/2010/01/31/co2-an-insignificant-trace-gas-part-three/&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In this case it's described as heating the air directly, which air then radiates energy out. But we observe no higher heating in the experiment.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;What's the explanation for the air not getting hotter?&lt;/p&gt;&#xA;" OwnerUserId="28819" LastEditorUserId="28819" LastEditDate="2023-04-15T16:45:01.167" LastActivityDate="2023-04-15T16:45:01.167" Title="Why did the air not heat up in this experiment demonstrating the atmospheric greenhouse effect?" Tags="|atmosphere|co2|greenhouse-gases|atmospheric-radiation|radiative-transfer|" AnswerCount="0" CommentCount="17" ContentLicense="CC BY-SA 4.0" />
  <row Id="25111" PostTypeId="2" ParentId="16078" CreationDate="2023-04-15T06:55:13.953" Score="2" Body="&lt;p&gt;Is rapid sea level rise unusual?&lt;/p&gt;&#xA;&lt;p&gt;Yes.&lt;/p&gt;&#xA;&lt;p&gt;Is It unprecedented?&lt;/p&gt;&#xA;&lt;p&gt;No.&lt;/p&gt;&#xA;&lt;p&gt;That then prompts the question: Is a less than 0.25 meter rise in sea level over the past 140 years or so considered &amp;quot;rapid&amp;quot; in terms of geological time?&lt;/p&gt;&#xA;&lt;p&gt;There have been three documented &lt;em&gt;meltwater pulse&lt;/em&gt; events during which sea level rose dramatically in relatively short periods of time following the most recent glacial period that reached maximum ice around 18,000 years ago.&lt;/p&gt;&#xA;&lt;p&gt;From the Wikipedia article &lt;a href=&quot;https://en.wikipedia.org/wiki/Past_sea_level&quot; rel=&quot;nofollow noreferrer&quot;&gt;'Past Sea level'&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Meltwater pulse 1A was a 13.5 m rise over about 290 years centered at 14,200 years ago and Meltwater pulse 1B was a 7.5 m rise over about 160 years centered at 11,000 years ago.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Meltwater pulse 1C was centered at 8,000 years ago and produced a rise of 6.5 m in less than 140 years, such that sea levels 5000 years ago were around 3m lower than present day, as evidenced in many locations by fossil beaches.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Pulse 1A was approximately 27X the rate of change since 1880.&lt;br /&gt;&#xA;Pulse 1B was approximately 26X the rate of change since 1880.&lt;br /&gt;&#xA;Pulse 1C was approximately 26X the rate of change since 1880.&lt;/p&gt;&#xA;&lt;p&gt;Compared to rates of change approximately six meters (6,000mm) per 140 years, is a rise of less than 0.25m (250mm) over 135 years considered &amp;quot;rapid&amp;quot;?&lt;/p&gt;&#xA;&lt;p&gt;Maybe. Maybe not. After all, for the next 5,000 years following Pulse 1C sea level has only risen about 3 meters (3,000mm). This equates to a rate about 1/3 that observed over the past 140 years. So is 3X the rate of the last 5,000 years &amp;quot;rapid&amp;quot;? Or is it only &amp;quot;slightly elevated&amp;quot; when compared to past events which showed roughly 75X the average rate of change of the past 5,000 years?&lt;/p&gt;&#xA;&lt;p&gt;Should this be cause for concern?&lt;/p&gt;&#xA;&lt;p&gt;With regard to human culture, absolutely. If current trends continue, in a few centuries many coastal cities will be underwater. That's a serious problem that needs to be considered and acted upon if it can be shown that we have the capability to slow the rate at which sea level is rising.&lt;/p&gt;&#xA;&lt;p&gt;Does this mean we should base our argument of what is &amp;quot;normal&amp;quot; on selective data that makes things look worse and more anomalous than they actually are?&lt;/p&gt;&#xA;&lt;p&gt;No, doing that just makes us look like we're a bunch of Chicken Littles crying that the sky is falling when we choose the absolute minimum sea level for the past tens of millions of years, at the height of the most recent ice age 18,000 years ago, as our baseline for what is &amp;quot;normal&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Just for some very long term context:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://news.mongabay.com/2008/03/cretaceous-sea-levels-were-550-feet-higher-than-today/&quot; rel=&quot;nofollow noreferrer&quot;&gt;80 million years ago&lt;/a&gt; sea level was 170 meters (550 feet) higher than current levels.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.usgs.gov/media/images/coastline-eastern-us-changesslowly&quot; rel=&quot;nofollow noreferrer&quot;&gt;Three million years ago&lt;/a&gt; sea level was 50 meters (165 feet) higher than current levels.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.e-education.psu.edu/earth107/node/1496&quot; rel=&quot;nofollow noreferrer&quot;&gt;125,000 years ago&lt;/a&gt;, at the most recent warm peak, sea level was 8-10 meters (26-33 feet) higher than current levels.&lt;/p&gt;&#xA;&lt;p&gt;At its lowest during the last ice age around 18,000 years ago, when roughly one-third of Earth's total land mass was covered in ice, sea level was 122 meters (400 feet) lower than current levels. As far as we can tell, that's the lowest sea level has been for at least 100 million years, and likely for much longer.&lt;/p&gt;&#xA;&lt;p&gt;Anthropogenic climate change is accelerating the rate at which the Earth is warming. How much of the current rate of change is anthropogenic and how much is due to other factors, such as solar activity variation, irregularities in the Earth's orbit, and plate tectonics is arguable.&lt;/p&gt;&#xA;&lt;p&gt;It is no less foolish to pretend that without anthropogenic factors the Earth would not be warming at all than it is to pretend none of our current warming is anthropogenic. In the long term the Earth will almost certainly continue a warming trend for the next several tens of thousands of years with or without humans living on its surface. After all, the Earth is still emerging from the last ice age 18,000 years ago.&lt;/p&gt;&#xA;&lt;p&gt;Unfortunately for humans, our culture and societies also emerged during a time when the Earth has been considerably cooler than is historically typical and we're best adapted to live in a world that is cooler than has historically been the case over the past hundreds of thousands of years. That's not an Earth problem. That's a human problem.&lt;/p&gt;&#xA;" OwnerUserId="28822" LastActivityDate="2023-04-15T06:55:13.953" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25112" PostTypeId="1" AcceptedAnswerId="25119" CreationDate="2023-04-15T11:22:43.700" Score="2" ViewCount="102" Body="&lt;p&gt;Having learned about the Milankovitch cycles, I've found two entirely separate explanations from different sources on how the combination of precession and eccentricity changes affect glaciation vs deglaciation. Some sources I've found state that the combination of high eccentricity and Northern Hemisphere winter at aphelion (and hence summer at perihelion) leads to glaciation in the Northern Hemisphere, since the winters are particularly cold (both because high eccentricity means the distance from the sun at aphelion is particularly high, and because aphelion winters would be longer compared to the corresponding perihelion summers, since the earth moves slower around the sun at aphelion compared to the perihelion). However, other sources state that it is the amount of sunlight during summer solstice in the Northern Hemisphere summer that drives deglaciation. Namely, high eccentricity in combination with a perihelion Northern Hemisphere summer would now lead to &lt;em&gt;deglaciation&lt;/em&gt;, not glaciation. This is because with high eccentricity, the distance to the sun at summer would be particularly low, hence sunlight intensity would be particularly high during the summers. On the other hand, all sources I've seen agree that high obliquity favors deglaciation.&lt;/p&gt;&#xA;&lt;p&gt;So which is it? Does high eccentricity in combination with perihelion Northern Hemisphere summers (and hence aphelion winters) lead to deglaciation or glaciation? I'd love a direct answer together with an explanation.&lt;/p&gt;&#xA;" OwnerUserId="28823" LastActivityDate="2023-04-18T15:57:05.450" Title="Effect of eccentricity and axial precession on glaciation/deglaciation" Tags="|paleoclimatology|climatology|earth-system|glaciation|milankovitch-cycles|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25113" PostTypeId="1" CreationDate="2023-04-15T12:44:08.040" Score="3" ViewCount="65" Body="&lt;p&gt;In a lecture book we read about latent heat of moist air.&lt;/p&gt;&#xA;&lt;p&gt;I would have guessed, that the total specific enthalpy of moist air, comprised of &lt;span class=&quot;math-container&quot;&gt;$m_d$&lt;/span&gt; kg of dry air and &lt;span class=&quot;math-container&quot;&gt;$m_v$&lt;/span&gt; kg of water vapor is (we have just a mixture of two gases...)&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$h_{total} = \frac{c_p^d \cdot T \cdot m_d+c_p^v \cdot T \cdot m_v }{m_d+m_v}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Defining absolute humidity as&#xA;&lt;span class=&quot;math-container&quot;&gt;$$q = \frac{m_v}{m_d+m_v}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;this is written as:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$h_{total} = c_p^d\cdot (1-q)\cdot T + c_p^v\cdot q\cdot T $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;In the lecture, however, we learned&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$h_{total} = c_p^d\cdot (1-q)\cdot T + L \cdot q $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;with L denoting the enthalpy of vaporization (aka latent heat). I know, what latent heat physically means, but anyway, I do not understand why it is included in h for the gas.&lt;/p&gt;&#xA;&lt;p&gt;My questions:&lt;/p&gt;&#xA;&lt;p&gt;Q1: The lecture book says literally, that the enthalpy of pure water vapor is&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$H_v = m_v \cdot L$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;so, in contrast to my equation, the &lt;span class=&quot;math-container&quot;&gt;$c_p^v$&lt;/span&gt; is not included at all. This would mean, water vapor just contributes a constant to h which doesn't depend anymore on T - for me this sounds weird, since we are still talking about a gas...&lt;/p&gt;&#xA;&lt;p&gt;Q2: Why is it required at all, to include L into the enthalpy of moist air? After liquid water has vaporized (for whatever reason) it is just a &amp;quot;regular&amp;quot; gas with another specific gas constant and also the mixture of those two gases behaves like an ideal gas to a good approximation. So, to make my question  more clear: If L for water is included in h, why isn't the enthalpy of vaporization of liquid dry air also included? Physically there is no difference, but it would be somehow ridiculous to include latent heat of liquid air into the enthalpy of the atmospheric gas.&lt;/p&gt;&#xA;&lt;p&gt;I see no reason to do so - although I believe, that good arguments exist.&lt;/p&gt;&#xA;&lt;p&gt;This is the copy from the book: Unfortunately, since it is a german book, D and L denote here vapor (&amp;quot;Dampf&amp;quot;) and dry air (&amp;quot;Luft&amp;quot;), respectively.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/FvsVa.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FvsVa.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2023-04-15T12:58:38.257" LastActivityDate="2024-04-02T13:02:00.217" Title="Why is latent heat of water vapor included in specific enthalpy of moist air?" Tags="|meteorology|atmosphere|atmosphere-modelling|thermodynamics|air|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25114" PostTypeId="1" CreationDate="2023-04-17T07:54:36.243" Score="1" ViewCount="40" Body="&lt;p&gt;Today (17/04/2023) Luleå in Sweden has one of the lowest air quality values in the world according, to Microsoft's air quality map. Other regions with a similar value are near deserts or large urban areas. However according to &lt;a href=&quot;https://www.wunderground.com/health/se/lule%C3%A5&quot; rel=&quot;nofollow noreferrer&quot;&gt;Weather underground&lt;/a&gt; the same PM value in Luleå is classified as good air quality.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.wunderground.com/health/se/lule%C3%A5&quot; rel=&quot;nofollow noreferrer&quot;&gt;It is not pollen season&lt;/a&gt; or any news I could find about the poor air quality. What are other sources for high PM value that are relevent for Luleå, and is PM10 indicative of poor air quality?&lt;/p&gt;&#xA;&lt;p&gt;Note: I have never visited Luleå so there may be conditions I am not aware of.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6CSKF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6CSKF.png&quot; alt=&quot;Air Quality map of Luleå&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28829" LastActivityDate="2023-04-17T08:53:18.357" Title="Is Luleå's PM10 indicative of poor air quality?" Tags="|atmosphere|air-pollution|air-quality|particulates|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25115" PostTypeId="2" ParentId="25114" CreationDate="2023-04-17T08:53:18.357" Score="1" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Lule%C3%A5&quot; rel=&quot;nofollow noreferrer&quot;&gt;Luleå&lt;/a&gt; has a very large steel industry. This coupled with weather conditions, such as temperature inversions would be likely factors for high readings in particulate matter air pollution.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.gem.wiki/SSAB_Lule%C3%A5_steel_plant&quot; rel=&quot;nofollow noreferrer&quot;&gt;steel plant&lt;/a&gt; produces 2.3 Mt of steel per annum.&lt;/p&gt;&#xA;&lt;p&gt;The site &lt;a href=&quot;https://en.tutiempo.net/air-quality/lulea.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;tutiempo.net&lt;/a&gt; has classified the air for &amp;quot;today&amp;quot;, 17 April 2023 as being very unhealthy.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-04-17T08:53:18.357" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25116" PostTypeId="1" CreationDate="2023-04-17T09:46:03.953" Score="1" ViewCount="72" Body="&lt;p&gt;I recently found a few rocks scattered in a valley, without any clues about where they may have come from (they did not look anything like the local soil, rocks, or layers of rock that could be seen in the surroundings).&lt;/p&gt;&#xA;&lt;p&gt;The rocks seem ferromagnetic (magnets are attracted to them) and have a high density (It feels similar to other metals, but I don't have good tools to measure mass/volume at the moment).&lt;/p&gt;&#xA;&lt;p&gt;I tested magnetism with a needle suspended on a string, and they may produce a weak magnetic field, but it's hard to tell.&lt;/p&gt;&#xA;&lt;p&gt;The other interesting characteristic are tube-like formations as seen in these pictures:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9Ak4k.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9Ak4k.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6vFvL.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6vFvL.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9agNH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9agNH.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Any ideas about what it could be?&lt;/p&gt;&#xA;" OwnerUserId="28831" LastActivityDate="2023-04-17T10:52:15.173" Title="Identifying dense magnetic rock with tubular features" Tags="|rocks|meteorite|rock-magnetism|" AnswerCount="1" CommentCount="0" ClosedDate="2023-04-18T03:37:05.973" ContentLicense="CC BY-SA 4.0" />
  <row Id="25117" PostTypeId="2" ParentId="25116" CreationDate="2023-04-17T10:52:15.173" Score="4" Body="&lt;p&gt;The items look like &lt;a href=&quot;https://en.wikipedia.org/wiki/Slag&quot; rel=&quot;nofollow noreferrer&quot;&gt;slag&lt;/a&gt;, the dumped wasted product of metal smelting. The high density suggests a high metal content. The magnetic properties suggests a significant iron content and the smooth curved surfaces and internal bubbles suggests solidification from a molten material. A smooth surface or a glassy appears indicates rapid cooling.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-04-17T10:52:15.173" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25118" PostTypeId="2" ParentId="3169" CreationDate="2023-04-18T12:45:59.783" Score="2" Body="&lt;p&gt;In addition to what's mentioned in the other answers, there's also the fact that the biological activity in forest soils is typically greater than elsewhere, especially further away from the equator where nutrient cycling is not as rapid; this is essentially a practically permanent state of composting, and produces a significant amount of heat, even during the colder parts of the year.&lt;/p&gt;&#xA;" OwnerUserId="28834" LastActivityDate="2023-04-18T12:45:59.783" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25119" PostTypeId="2" ParentId="25112" CreationDate="2023-04-18T15:57:05.450" Score="1" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Does high eccentricity in combination with perihelion Northern Hemisphere summers (and hence aphelion winters) lead to deglaciation or glaciation?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Paradoxically, it's the other way around, at least with regard to when glaciations start. The bellwether metric used by many is the mean July temperature at 65° north latitude. When that drops below 0° C is a key trigger for the start of a glaciation. The conditions that lead to this are a relatively high eccentricity and aphelion in June or July. It doesn't matter that the summers are long. What matters is that summers have become mild enough so that snow can last over the summer, and thus accumulate over multiple years.&lt;/p&gt;&#xA;&lt;p&gt;The last glaciation started its end about 13000 years ago, and was pretty much complete 11500 years ago. That was when aphelion was in January (making for a long, cold winter) and perihelion was in July (making for a fierce but short summer). A long, cold winter is exactly what is not wanted for the onset of a glaciation. It doesn't snow in the deepest parts of winter in the far north; -40° C or colder is too cold for the atmosphere to hold much moisture. Keep in mind that much of Antarctica and much of the very far north are technically deserts. Snowfall in the far north occurs mostly in autumn and spring. Those short but fierce summers 13000 to 11500 years ago made July temperatures in the far north exceed 0° C; that winters were long and cold back then was a bit irrelevant. This is why the July temperature at 65° north latitude is such a key metric.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-04-18T15:57:05.450" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25120" PostTypeId="2" ParentId="25095" CreationDate="2023-04-19T11:17:26.993" Score="1" Body="&lt;p&gt;The Earth is currently in the midst of an ice age, and has been for 2.6 million years. (Some say 33 million years as that was when the ice sheet started forming over Antarctica.) For the last 2.6 million years, the Earth has alternated between being almost ice-free in much of the Northern Hemisphere (except for Greenland) and extensively covered with ice in over northern parts of the Northern Hemisphere. The former are called interglacials while the latter are called glaciations.&lt;/p&gt;&#xA;&lt;p&gt;The period of the oscillations from one interglacial to the next used to be about 41000 years, but switched to 100000 years about a million years ago. The coldness and extent of the glaciations also increased at that time. Explaining this is the 100000 year problem. There are multiple hypotheses, none universally accepted.&lt;/p&gt;&#xA;&lt;p&gt;Since that switch, the interglacials have tended to be much shorter in duration than are the glaciations. The previous interglacial, the Eemian, lasted about 15000 years. The glaciations suffer lots of ups and downs. Snowfall happens mostly at the ice sheet margins; even at 100% relative humidity, air at -60° C does not contain much moisture. Those margins are subject to fluctuation. As temperature rises, ice at the margins melts and thereby sends boatloads of nutrients to the oceans. Algae celebrate and drain carbon dioxide from the atmosphere, causing temperatures to drop.&lt;/p&gt;&#xA;&lt;p&gt;It's only when July temperatures at 65° north latitude consistently rise above 0° C that melting becomes persistent. Once persistent melting has started, it can quickly becomes an unstoppable train of melting. That's what happened about 12000 years ago or so.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-04-19T11:17:26.993" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25121" PostTypeId="2" ParentId="25109" CreationDate="2023-04-19T13:07:12.860" Score="4" Body="&lt;p&gt;To understand the problem there are a few fundamental conditions we need to realise. First, we can look at the climatic aspect of a glacier. In this example I will focus on mountain or valley glaciers in temperate to polar regions where we have a clear winter and summer season.&lt;/p&gt;&#xA;&lt;p&gt;In winter snow accumulates on the glacier due to a combination of many sources but primarily snow fall, avalanching and snow drifting. Snow will accumulate across the surface but often with larger snow depths at the upper part of the glacier. The reason for this is that glacier form in places with excess snow accumulating, snow-catching areas, if you wish. So after the winter the glacier is snow covered with possibly deeper snow packs at higher elevation.&lt;/p&gt;&#xA;&lt;p&gt;In summer melting will occur. Melting is largely an effect of air temperature which decreases with altitude due to the atmospheric lapse rate(s). This means less melting will occur at high elevations and more at lower elevations.&lt;/p&gt;&#xA;&lt;p&gt;The net result is that the glacier is growing in thickness at higher elevations and decreasing in thickness at lower elevations. Clearly if no movement of the ice would occur the lower part of the glacier would vanish and the upper part be &amp;quot;infinitely&amp;quot; high. Enter ice dynamics.&lt;/p&gt;&#xA;&lt;p&gt;Ice deforms as a plastic material when its thickness is about 30-40 m of ice. This means that the ice can move by the ice body deforming akin to a dough. Hence the changes in glacier thickness due to accumulation and melting can be counteracted by the glacier moving excess mass from the upper part of the glacier to its lower part.&lt;/p&gt;&#xA;&lt;p&gt;As long as the climate is stable the glacier will receive roughly the same amount of snow every year and the loss of ice from melting would also be constant over years. The glacier will then be stable in size because the glacier flow compensates the gains and losses in different areas every year.&lt;/p&gt;&#xA;&lt;p&gt;If we get a change in climate the amount of snow accumulation and the melting will change due to changes in winter precipitation and summer temperature. This will affect the amounts of excess and deficit in the upper and lower parts of the glacier and also its dynamics.&lt;/p&gt;&#xA;&lt;p&gt;Looking at the terminus of the glacier we can view this as follows. A stable glacier is one where the melting at the terminus is compensated by ice flow replacing the ice loss by moving new ice into the position of the ice lost. If the melt at the terminus is larger (due to warming), then the ice loss will be larger than the ice flow trying to compensate the loss and the glacier terminus retreats. Note that ice flow continues (down valley) while the glacier retreats up-valley. For a climate cooling the melt decreases and ice will over-compensate the loss giving an advance of the glacier.&lt;/p&gt;&#xA;&lt;p&gt;Hence the answer is that you cannot split dynamics from climate in the response of a glacier. The simple description above can be complicated further but that is probably worthy of a course in glaciology or deeper study of a book on glaciology such as The Physics of Glaciers by Kurt Cuffey and W.S.B. Paterson (Academic Press 2006).&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="81" LastEditDate="2023-04-23T12:51:24.877" LastActivityDate="2023-04-23T12:51:24.877" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25123" PostTypeId="2" ParentId="25105" CreationDate="2023-04-21T14:01:32.960" Score="4" Body="&lt;p&gt;Fractional crystallization indeed makes magmas more silicic. However, you'll never reach a magma composition with 100 % silica, which could then cool and crystallize as quartz. The starting material (i.e., mantle rocks like peridotite) is just too mafic. For this part, see answers to &lt;a href=&quot;https://earthscience.stackexchange.com/q/20117/18081&quot;&gt;Why aren't there ultra acid igneous rocks?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;If you are thinking of the crystals left over by the fractional crystallization process, generally referred to as &amp;quot;extract&amp;quot;, &amp;quot;cumulate&amp;quot;, or &amp;quot;residue&amp;quot;, they are always &lt;em&gt;less&lt;/em&gt; silicic than the starting material. It has to be, if you want to make the magma more silicic while keeping the mass-balance. The process can be graphically represented like this (redrawn after &lt;a href=&quot;https://link.springer.com/book/10.1007/978-94-017-3373-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cox et al., 1979&lt;/a&gt;):&lt;/p&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/LhsMo.png&quot; width=&quot;400&quot; /&gt;&#xA;&lt;p&gt;The three diagrams represent the fractional crystallization process of a parental magma (PM), yielding a diffentiated magma (DM), more silicic, and a less silicic residue (R) consisting of one (top) to three (bottom) minerals. The mass balance, for an element &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt;, can then be written as:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$C_0^{\alpha} = FC_L^{\alpha} + (1 - F)\displaystyle\sum_{i=1}^n (m_i c_i^{\alpha})$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$C_0^{\alpha}$&lt;/span&gt; is the concentration of said element in the parental magma, &lt;span class=&quot;math-container&quot;&gt;$C_L^{\alpha}$&lt;/span&gt; the concentration of the element in the differentiated magma, &lt;span class=&quot;math-container&quot;&gt;$F$&lt;/span&gt; the fraction of liquid remaining, &lt;span class=&quot;math-container&quot;&gt;$m_i$&lt;/span&gt; is the mass fraction of each of the &lt;span class=&quot;math-container&quot;&gt;$n$&lt;/span&gt; minerals in the cumulate, and &lt;span class=&quot;math-container&quot;&gt;$c_i^{\alpha}$&lt;/span&gt; is the concentration of element &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt; in mineral &lt;span class=&quot;math-container&quot;&gt;$i$&lt;/span&gt;. You see that even if somehow the diffentiated magma had a 100 wt% SiO2 composition, the crystals left in the residue would be less silicic, hence not quartz.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2023-04-21T14:01:32.960" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25125" PostTypeId="1" CreationDate="2023-04-22T01:47:52.250" Score="4" ViewCount="46" Body="&lt;p&gt;What radar technology would be best to measure the attributes of ocean waves near (under 2k distance) the shoreline?&lt;/p&gt;&#xA;" OwnerUserId="28848" LastActivityDate="2023-04-22T01:47:52.250" Title="Using radar to measure ocean waves along the shoreline" Tags="|oceanography|waves|radar|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25126" PostTypeId="2" ParentId="8238" CreationDate="2023-04-22T09:24:09.487" Score="3" Body="&lt;p&gt;You can, but the form changes. it is&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$N^2=\frac{g}{T}(\frac{dT}{dz} + Γ)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$Γ$&lt;/span&gt; is the dry adiabatic lapse rate, given by &lt;span class=&quot;math-container&quot;&gt;$g/c_p$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$c_p$&lt;/span&gt; is the specific heat of air at constant pressure.&lt;/p&gt;&#xA;" OwnerUserId="28849" LastEditorUserId="2470" LastEditDate="2023-04-23T02:00:27.530" LastActivityDate="2023-04-23T02:00:27.530" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25127" PostTypeId="1" AcceptedAnswerId="25132" CreationDate="2023-04-23T01:24:37.113" Score="2" ViewCount="63" Body="&lt;p&gt;I have heard that there are hot springs in Greece which contain high amounts of ions and minerals (namely Lithium) that some people believe has beneficial impact on mental health.&lt;/p&gt;&#xA;&lt;p&gt;I can't verify/know the validity of those claims but I am curious if anyone knows the measurements of the actual grams of mineral/gallon amounts of various minerals that are in these human usable hot springs?&lt;/p&gt;&#xA;&lt;p&gt;Answers to this question are any hot spring of your choice that has a link claiming to have health benefits and the actual scientifically measured ratios of its (grams of mineral)/gallon or liter of water.&lt;/p&gt;&#xA;" OwnerUserId="5337" LastEditorUserId="2470" LastEditDate="2023-04-23T02:04:13.753" LastActivityDate="2023-04-25T12:45:02.867" Title="Is there a way to know what the concentrations of various minerals and ions in the water of a human usable hot spring are?" Tags="|water|mineralogy|open-data|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25128" PostTypeId="1" AcceptedAnswerId="25131" CreationDate="2023-04-23T17:11:51.913" Score="6" ViewCount="93" Body="&lt;p&gt;In this satellite pic, on the land is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Columbia_River&quot; rel=&quot;nofollow noreferrer&quot;&gt;Columbia river&lt;/a&gt; on the western side of North America.&lt;/p&gt;&#xA;&lt;p&gt;I was amazed to see the channel within the sea, more than 125 km long.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Can it be concluded, based on this picture alone, that the channel was formed when the entirety of it was above sea level? In other words, is that the most plausible known mechanism for the formation of such sub-sea channels?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Can it also be concluded that the left end of the channel, where it divides into three branches, was the ancient delta with the ancient coast further to the left?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;What is the reason for the sub-sea channel starting tens of km away from the present coast? In the past, would the channel have extended right till the present mouth of the river, and then got filled up by sediments in the later millennia?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WN8wH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WN8wH.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12269" LastEditorUserId="12269" LastEditDate="2023-04-24T18:02:11.640" LastActivityDate="2023-04-25T01:52:23.200" Title="Were sub-sea river channels formed when the land was above sea level?" Tags="|sea-level|ice-age|ice-sheets|sea-ice|sea-floor|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25129" PostTypeId="1" CreationDate="2023-04-23T21:07:41.840" Score="1" ViewCount="110" Body="&lt;p&gt;There is an &lt;a href=&quot;https://www.bbc.com/news/world-asia-india-65299807&quot; rel=&quot;nofollow noreferrer&quot;&gt;article&lt;/a&gt; on the BBC talking about an alarming increase of heatwaves in India. It also says that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Average temperatures in India have risen by around 0.7% between 1901 and 2018,&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;partly due to climate change.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The second part is vague and it is also getting close to a stereotype. In this case it is obvious that the growth of the cities and the expansion of the urban heat islands has a role. But it won't stop there because vast tract of forests have been cut down to make space for roads, railroads and other infrastructure. I guess that also the expansion of the arable land has a role. Once the surface is flattened the winds carry quickly away the moist and the air that was refreshed by water evaporation.&lt;/p&gt;&#xA;&lt;p&gt;Is there any study that tries to quantify these factors and estimate the impact on the temperatures rise?&lt;/p&gt;&#xA;" OwnerUserId="18774" LastEditorUserId="6" LastEditDate="2023-04-26T07:25:43.917" LastActivityDate="2023-04-26T07:25:43.917" Title="How much average temperature increase in India is due to Urbanisation and population growth?" Tags="|meteorology|temperature|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25130" PostTypeId="2" ParentId="25129" CreationDate="2023-04-24T09:12:51.967" Score="-2" Body="&lt;p&gt;Regarding population growth, a quick and dirty computation is as follows:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;a human body emits about 80W in form of heat.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;global warming arises from an increase in radiative forcing of about 2.43W/m2 (IPCC report, chpater 6);&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;radiative forcing due to the increases in the well-mixed greenhouse&#xA;gases from the   pre-industrial (1750) to present time (1998) is now&#xA;estimated to be +2.43 Wm−2&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The population density increased in the time span you provided of almost a factor 6, from ~100 inhabitants/km2 to ~600 inhabitants/km2. However, at the beginning the radiative heat from human bodies alone was about 0,004 W/m2, today is a factor 6 --&amp;gt; 0,024 W/m2, even in absolute terms still 100 times less than the increased radiative forcing from greenhouse gases.&lt;/p&gt;&#xA;&lt;p&gt;So no, the increase in number of living heat sources has no tangible direct effect on the temperature increase.&lt;/p&gt;&#xA;&lt;p&gt;Answering to your &lt;strong&gt;Update&lt;/strong&gt;: of course there is a link between (over)population and climate change.&#xA;If the added (over)population will emit as much CO2eq as the average (please note: average, not median) western or the chinese o russian or &lt;a href=&quot;https://www.worldometers.info/co2-emissions/co2-emissions-per-capita/&quot; rel=&quot;nofollow noreferrer&quot;&gt;or or&lt;/a&gt; citizen, then there is a linear relation ... between average temperatures anywhere in the world and the local increase in population.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, reg. your &lt;strong&gt;Update&lt;/strong&gt;: please define overpopulation: do you mean that an increase of the population in India of a factor 6 between 1901 and 2018 is overpopulation, while an increase of population in California of a factor 40 between 1901 and 2018 is ... population increase?&lt;/p&gt;&#xA;" OwnerUserId="5887" LastEditorUserId="5887" LastEditDate="2023-04-25T21:35:15.640" LastActivityDate="2023-04-25T21:35:15.640" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25131" PostTypeId="2" ParentId="25128" CreationDate="2023-04-24T21:39:28.543" Score="6" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Can it be concluded, based on this picture alone, that the channel was formed when the entirety of it was above sea level? In other words, is that the most plausible known mechanism for the formation of such sub-sea channels?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Not in this case. While some submarine canyons were formed when sea levels were much lower, the Astoria Canyon, which is what you are asking about, is not one of them. Examples of what are now submarine canyons but were carved by rivers when sea levels were lower include submarine canyons in the Mediterranean Sea. The Mediterranean nearly dried out when it was cut off from the Atlantic Ocean about 6 million years ago. This resulted in rivers such as the Nile cutting long canyons that were later submerged.&lt;/p&gt;&#xA;&lt;p&gt;What about the Astoria Canyon?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/guHN6.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/guHN6.jpg&quot; alt=&quot;Astoria Canyon depth contour plot; see description below&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;sub&gt;Image source: &lt;a href=&quot;https://oceanexplorer.noaa.gov/explorations/lewis_clark01/background/geology/geology.html&quot; rel=&quot;noreferrer&quot;&gt;https://oceanexplorer.noaa.gov/explorations/lewis_clark01/background/geology/geology.html&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;As seen in the above counter plot, the Astoria Canyon starts at about 200 meters below sea level, at the end of the continental shelf, and carries on to the bottom of the continental rise. Sea levels fell by about 125 meters at the peak of the last glaciation, so it wasn't a river carving a canyon in land that was above sea level at the time. This does not mean that the Columbia River did not play a role in the formation of the Astoria Canyon.&lt;/p&gt;&#xA;&lt;p&gt;One of the leading hypothesized formation mechanisms of the Astoria Canyon is the huge amounts of sediment deposited by the Colorado River from the multiple Missoula Floods that resulted from the breaching of ice dams that formed massive glacial lakes in western Montana during the latest glaciation (and possibly during previous glaciations). These floods scoured eastern Washington, creating the Channeled Scablands. Those sediments were then deposited past the mouth of the Columbia River. Turbidity currents carrying those sediments then scoured their way down the steep continental rise -- but not the much flatter continental shelf.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2023-04-25T01:52:23.200" LastActivityDate="2023-04-25T01:52:23.200" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25132" PostTypeId="2" ParentId="25127" CreationDate="2023-04-25T12:45:02.867" Score="1" Body="&lt;p&gt;The answer to the question in the title is yes, absolutely, even if you buy some bottle of water you will find that the list of minerals dissolved in it is analyzed and written on the label.&lt;/p&gt;&#xA;&lt;p&gt;The specific question in the text, about lithium and mental health, this is a mix-up of two different concept:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;there is lithium dissolved in hot geothermal water;&lt;/li&gt;&#xA;&lt;li&gt;lithium is the base ingredient of drugs used to treat bipolar disorders;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Whether this second question is true, it would be better to ask to the medical practitioners, if bathing in lithium rich water can improve mental health ...&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2023-04-25T12:45:02.867" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25134" PostTypeId="1" AcceptedAnswerId="25135" CreationDate="2023-04-25T17:57:17.190" Score="1" ViewCount="61" Body="&lt;p&gt;Bucharest becomes a huge city. Bucharest has never seen such dense population before. from 1947 to 1990 there was a communist government in Romania. 1988 Armenia earthquake with 38,000 deaths shows us that constructions in the Soviet Union are not strong enough. What are the consequences of occurrence a powerful earthquake near Bucharest. An earthquake like what happened in Turkey–Syria in 2023. in bad scenario how many people will lose their lives?&lt;/p&gt;&#xA;" OwnerUserId="28862" LastEditorUserId="28862" LastEditDate="2023-04-25T19:31:57.430" LastActivityDate="2023-04-26T09:24:24.957" Title="How many people will lose their lives if a big earthquake shakes Bucharest?" Tags="|earthquakes|seismology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25135" PostTypeId="2" ParentId="25134" CreationDate="2023-04-25T21:22:21.947" Score="0" Body="&lt;p&gt;Zero (in the meaning of basic seismolgical aspect, not in terms of people): we can partially predict earthquakes. However, an earthquake is characterized by three questions: when, where, how big?&lt;/p&gt;&#xA;&lt;p&gt;At best, we can answer 2 out of 3 of the mentioned questions at the same time.&lt;/p&gt;&#xA;&lt;p&gt;First: we can give some boundaries on the magnitude of an earthquake hitting Bucharest, see for example this:&#xA;&lt;a href=&quot;https://www.researchgate.net/publication/309634750_Next_Future_Large_Earthquake_in_Romania_A_Disaster_Waiting_to_Happen&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/publication/309634750_Next_Future_Large_Earthquake_in_Romania_A_Disaster_Waiting_to_Happen&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Second: if we do know how big can an earthquake be, but we do not know when it will happen, we can assume it will happen tomorrow. So we can check scenarios for this hypotetical earthquake with the current knowledge of the building conditions:&#xA;&lt;a href=&quot;https://www.romaniajournal.ro/society-people/350000-buildings-seriously-damaged-45000-people-injured-or-dead-in-case-of-major-earthquake-in-romania/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.romaniajournal.ro/society-people/350000-buildings-seriously-damaged-45000-people-injured-or-dead-in-case-of-major-earthquake-in-romania/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Finally, &amp;quot;luckily&amp;quot; you have an historical example of a strong eartquake in the region:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/1940_Vrancea_earthquake&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/1940_Vrancea_earthquake&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So you can assume a lower boundary from that earthquake. Please ignore the origin of the building codes, it does not matter if it is a relic from the Kolkoz or if it has been spilled out from the capitalist world: even in the land of unbounded freedom, there are big issues with the construction codes, effective building standards and their resistance to earthquakes ... &lt;a href=&quot;https://www.nytimes.com/2018/10/04/us/san-francisco-building-codes-earthquakes.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nytimes.com/2018/10/04/us/san-francisco-building-codes-earthquakes.html&lt;/a&gt; and as well &lt;a href=&quot;https://www.sfchronicle.com/sf/article/earthquake-building-risk-safety-17782287.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sfchronicle.com/sf/article/earthquake-building-risk-safety-17782287.php&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5887" LastEditorUserId="5887" LastEditDate="2023-04-26T09:24:24.957" LastActivityDate="2023-04-26T09:24:24.957" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25136" PostTypeId="1" CreationDate="2023-04-26T11:13:00.653" Score="3" ViewCount="68" Body="&lt;p&gt;It is commonly known that 71% of the earth’s surface is covered by water. What sources can I look at that explain this calculation in more detail?&lt;/p&gt;&#xA;" OwnerUserId="28865" LastActivityDate="2023-04-26T11:13:00.653" Title="Source for 71% of the earth being water" Tags="|water|land-surface|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25137" PostTypeId="2" ParentId="14514" CreationDate="2023-04-27T05:08:24.127" Score="1" Body="&lt;p&gt;The effect on air going east or west may get called Corioles effect and looks similar, but has an entirely different cause and is called the Eötvös effect. It is a true force, unlike Coriolis, (which is just an effect due to the ground speed being different). As the air moves west to east, it's speed is added to the ground speed, so the centrifugal force as it goes around the earth is increased, and it is pushed outwards towards the equator. If going east to west, the centrifugal force is less, so it effectively falls inward towards the pole due to gravity.&lt;/p&gt;&#xA;" OwnerUserId="28401" LastActivityDate="2023-04-27T05:08:24.127" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25139" PostTypeId="2" ParentId="24465" CreationDate="2023-04-27T19:21:03.720" Score="3" Body="&lt;p&gt;These are now available for each Working Group report via its respective downloads page:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.ipcc.ch/report/ar6/wg1/downloads&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ipcc.ch/report/ar6/wg1/downloads&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.ipcc.ch/report/ar6/wg2/downloads&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ipcc.ch/report/ar6/wg2/downloads&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.ipcc.ch/report/ar6/wg3/downloads&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ipcc.ch/report/ar6/wg3/downloads&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;There are separate BibTeX files for each chapter, for example, the URL for the WG1 Chapter 1 references is,&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_References_Chapter01.bib&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ipcc.ch/report/ar6/wg1/downloads/report/IPCC_AR6_WGI_References_Chapter01.bib&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2023-04-27T19:21:03.720" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25140" PostTypeId="1" AcceptedAnswerId="25141" CreationDate="2023-04-27T20:05:35.343" Score="5" ViewCount="113" Body="&lt;p&gt;I am trying to remove the possible effect of &lt;a href=&quot;https://www.weather.gov/mhx/ensowhat#:%7E:text=This%20oscillating%20warming%20and%20cooling,other%20parts%20of%20the%20world.&quot; rel=&quot;nofollow noreferrer&quot;&gt;El Niño-Southern Oscillation&lt;/a&gt; (ENSO) phenomenon on sea bottom pressure records (sensor 4, 5 &amp;amp; 7, see map) that are located in front of the Pacific coast of Mexico.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dCPFf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dCPFf.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I have used the monthly average Ocean Bottom Pressure (OBP) data vs Ecuatorial Sea Surface Temperature (SST) Niño 3.4 data (see middle figure) in order to find a correlation, and thus calculate the linear regression coefficient to make a synthetic series and correct the OBP data of ENSO effect.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HGGGq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HGGGq.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As you can see in the previous figure El Niño 3.4 and the OBP 4 correlate very well (see figure below), El NIño 3.4 and the OBP 5 the correlation is negative (why?), meanwhile the OBP 7 with the SST the correlation is not clear.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aqXbO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aqXbO.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Anyone could help to understand why they correlate this way (I suppose that the depth of each sensor influences), or some suggestions to correct the OBP data for possible ENSO effect? Thanks :)&lt;/p&gt;&#xA;" OwnerUserId="27360" LastEditorUserId="18088" LastEditDate="2023-04-28T18:48:07.047" LastActivityDate="2023-04-28T18:48:07.047" Title="How to remove the ENSO signal on ocean bottom pressure data?" Tags="|oceanography|enso|correlation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25141" PostTypeId="2" ParentId="25140" CreationDate="2023-04-28T11:35:08.310" Score="2" Body="&lt;p&gt;I would do a fit of your data to the ENSO data and then evaluate the residual as your data without ENSO effect. For instance, in Matlab you could use mldivide or polyfit.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;dd = your_data;&#xA;enso = your_ENSO_timeseries;&#xA;X = ones(length(T),2); % create a matrix with the number of independent variables you want to fit. In your case, just ENSO + 1&#xA;% if you want to remove the trend at the same time you can add another column with just the time&#xA;% you can add any column that you want (e.g., seasonal cycle)&#xA;X(:,2) = enso; &#xA;B = X\dd; %use mldivide to solve the linear system of equations &#xA;enso_effect_on_your_timeseries=B(1)+B(2)*enso; % this is the ENSO effect&#xA;residual = dd - enso_effect_on_your_timeseries; % this is your data without the ENSO influence&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Now you can start analyzing the direct effect of ENSO in your OBP data. More specifically the magnitude of the effect at each location.&lt;/p&gt;&#xA;&lt;p&gt;It looks to me that OBP7 is in a deeper area, which will make the influence of surface features less important as you suggest. In terms of the difference between OBP4 and OBP5, one possible explanation is the shift in the magnitude (and in some cases even direction) of the ocean currents that is associated with ENSO especially along the shelf break. That could definitely be a factor.&lt;/p&gt;&#xA;&lt;p&gt;Just a minor point of preference: you are using El Niño 3.4 as your index for ENSO. I don't think there is anything wrong with the index, but considering that you are working with bottom pressure you might consider a different index that uses something apart from sea surface temperature (SST). My preferred index is MEI (&lt;a href=&quot;https://psl.noaa.gov/enso/mei/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://psl.noaa.gov/enso/mei/&lt;/a&gt;) because it combines SST factors with other variables such as differences in sea level pressure and wind.&lt;/p&gt;&#xA;" OwnerUserId="111" LastActivityDate="2023-04-28T11:35:08.310" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25142" PostTypeId="1" AcceptedAnswerId="25151" CreationDate="2023-04-28T18:55:46.870" Score="1" ViewCount="140" Body="&lt;p&gt;I see similar flavours of this question have been asked a few times, but I still don't see a satisfying answer. I am looking for data (maps) of the earth subsurface temperature at a depth sufficient to consider the temperature more or less constant (let's say in a range of ±5% ?). I am looking for data for:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Latitude: for polar, temperate and equatorial latitudes&lt;/li&gt;&#xA;&lt;li&gt;Time of the year: per season or per month&lt;/li&gt;&#xA;&lt;li&gt;Time of day: at noon and midnight&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Where can I find publicly available (free) data for this?&lt;/p&gt;&#xA;" OwnerUserId="28351" LastActivityDate="2023-05-01T12:34:34.477" Title="Map of earth subsurface temperature" Tags="|geology|temperature|open-data|geothermal-heat|land-surface-models|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25143" PostTypeId="1" CreationDate="2023-04-28T19:43:03.580" Score="4" ViewCount="85" Body="&lt;p&gt;When trying to calculate the adiabatic lapse rate of moist air based on known values of basic thermodynamic properties of the constituents (ice, water, vapor,...) I came to the following question:&lt;/p&gt;&#xA;&lt;p&gt;Lapse rate of moist air is less as compared to dry air because of the latent head released during condensation of water-vapor.&lt;/p&gt;&#xA;&lt;p&gt;Now, below 0°C  there is no liquid phase in equilibrium, therefore instead of the latent heat of evaporation &lt;span class=&quot;math-container&quot;&gt;$L_{ev}$&lt;/span&gt; of liquid I used the value for sublimation &lt;span class=&quot;math-container&quot;&gt;$L_{sub}$&lt;/span&gt;. However, of course &lt;span class=&quot;math-container&quot;&gt;$L_{sub} &amp;gt; L_{ev}$&lt;/span&gt;, so according to my calculations the lapse rate must have a discontinuity at 0°C (see graph, where the dotted line is the dry lapse rate).&lt;/p&gt;&#xA;&lt;p&gt;This discontinuity is not in accordance with observation - so where is my fault? What happens in rising air that this effect is not visible?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Z2n6h.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Z2n6h.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21047" LastActivityDate="2023-04-28T19:43:03.580" Title="Why atmospheric temperature lapse rate doesn't have a discontinuity at 0°C when ice is formed?" Tags="|meteorology|atmosphere|atmosphere-modelling|clouds|water-vapour|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25144" PostTypeId="1" CreationDate="2023-04-29T17:25:33.187" Score="3" ViewCount="123" Body="&lt;p&gt;This object is displayed in an exhibition, but nobody knows what it is.&#xA;It was part of the estate of a photographer whose father was one of the first meteorologists in Switzerland.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/AI5Lx.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/AI5Lx.jpg&quot; alt=&quot;unknown meteorological object1&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;EDIT:&lt;/strong&gt;&#xA;Adding more detailed pictures upon request in the comments.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/mrcVC.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/mrcVC.jpg&quot; alt=&quot;unknown meteorological object2&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/gIKNB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/gIKNB.jpg&quot; alt=&quot;unknown meteorological object6&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/riSFb.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/riSFb.jpg&quot; alt=&quot;unknown meteorological object5&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Wvm0Z.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Wvm0Z.jpg&quot; alt=&quot;unknown meteorological object4&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/J9yeI.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/J9yeI.jpg&quot; alt=&quot;unknown meteorological object3&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28882" LastEditorUserId="28882" LastEditDate="2023-05-05T14:56:13.717" LastActivityDate="2023-05-05T14:56:13.717" Title="What was this historic object used for?" Tags="|meteorology|history-of-science|history|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="25146" PostTypeId="1" AcceptedAnswerId="25148" CreationDate="2023-04-30T06:27:36.357" Score="4" ViewCount="330" Body="&lt;p&gt;I'm not talking about other artificial human activities like fossil fuels or cars or cattle farming. I meant just in terms of breathing, how much did the CO&lt;sub&gt;2&lt;/sub&gt; level of the earth increase because of the recent overpopulation, and is it significant?&lt;/p&gt;&#xA;&lt;p&gt;Like let's just say hypothetically that I stopped existing, how much global warming would I be saving?&lt;/p&gt;&#xA;" OwnerUserId="28885" LastEditorUserId="2470" LastEditDate="2023-05-02T06:17:51.907" LastActivityDate="2023-11-10T10:02:43.493" Title="How much does overpopulation affect the carbon dioxide concentration in the air in terms of just breathing?" Tags="|climate-change|greenhouse-gases|carbon|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25147" PostTypeId="1" CreationDate="2023-05-01T05:19:28.063" Score="1" ViewCount="121" Body="&lt;p&gt;So when I say radiometric dating, I'm specifically referring to U-Pb, Ar-K and Rb-SR rather than C14 as I think these are more accurate when it comes to corroborating an older earth. I've heard people mention how all of these methods rely on certain assumptions, even isochron dating, which is why they might not be as accurate as we may think. I'll list a few I've heard parroted:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Assuming starting parent-daughter ratios&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Assuming its a closed system&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Assuming the decay rate is constant&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Here's a creationist link that expands on these 3 (disclaimer--I'm not a creationist, I know AiG is pretty much all pseudoscience, but its difficult for me to find secular sources that provide as in-depth of an analysis as they have): &lt;a href=&quot;https://answersingenesis.org/geology/radiometric-dating/radiometric-dating-problems-with-the-assumptions/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://answersingenesis.org/geology/radiometric-dating/radiometric-dating-problems-with-the-assumptions/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So any help figuring out how important these assumptions are in relation to determining an accurate age for the Earth would be appreciated!&lt;/p&gt;&#xA;" OwnerUserId="28891" LastActivityDate="2023-06-23T02:46:28.927" Title="How important or necessary are assumptions when it comes to radiometric dating?" Tags="|geology|earth-history|dating|geochronology|isotopic|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25148" PostTypeId="2" ParentId="25146" CreationDate="2023-05-01T08:49:43.727" Score="9" Body="&lt;p&gt;Human and animal respiration has no global warming impacts. The CO&lt;sub&gt;2&lt;/sub&gt; released by respiration is in balance with the CO&lt;sub&gt;2&lt;/sub&gt; absorbed by the plants that became the foods that were the source of the CO&lt;sub&gt;2&lt;/sub&gt; released by breathing.&lt;/p&gt;&#xA;&lt;p&gt;With the production, storage, transport and processing of foods for humans and domesticated animals there are emissions that are derived from fossil fuel burning, that are in addition, and are not balanced by food plants absorbing CO&lt;sub&gt;2&lt;/sub&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SysoZ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SysoZ.jpg&quot; alt=&quot;Food and respiration&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(image from Veritas Press)&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="2470" LastEditDate="2023-05-02T06:17:30.820" LastActivityDate="2023-05-02T06:17:30.820" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25149" PostTypeId="1" CreationDate="2023-05-01T10:35:17.293" Score="1" ViewCount="141" Body="&lt;p&gt;How can you calculate planetary surface temperatures from first principles? The obvious application is for Earth, with a surface temperature of &lt;span class=&quot;math-container&quot;&gt;$288$&lt;/span&gt;K. I want a calculation with &lt;em&gt;no fudge factors&lt;/em&gt; (i.e., factors calculated knowing the final result) and that also works for Venus and Mars (with the adequate parameters). I've come across some derivations (listed below, and in other posts here) but they all employ a fudge factor at some point. Overall, what I'd like is a full set of equations (algebraic or differential, with well-justified boundary conditions) that give the correct answer.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;First attempt&lt;/strong&gt;: Based on a one layer model of the atmosphere, with an emissivity of &lt;span class=&quot;math-container&quot;&gt;$\epsilon=0.8$&lt;/span&gt;, we get&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$T_{p} = \left(\frac{2}{2-\epsilon}\right)^{1/4}T_{a} = 288$&lt;/span&gt;K&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$T_{a}$&lt;/span&gt; is the temperature at the top of the atmosphere given by the blackbody calculation.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Problems:&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;1a. The emissivity is a fudge factor we calculated knowing the final answer. Is there an independent estimate or measurement of the emissivity?&lt;/p&gt;&#xA;&lt;p&gt;1b. If we take &lt;span class=&quot;math-container&quot;&gt;$\epsilon = 1$&lt;/span&gt;, this gives as an upper bound on how much heating you can expect on any planet, namely &lt;span class=&quot;math-container&quot;&gt;$2^{1/4}$&lt;/span&gt; times the blackbody estimate. This upper bound is clearly surpassed on Venus.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Second attempt&lt;/strong&gt;: The lapse rate of the lower atmosphere is &lt;span class=&quot;math-container&quot;&gt;$\Gamma = 6.5$&lt;/span&gt; K/km, so&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$T_{p} = T_{a} + h\Gamma$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;and we get &lt;span class=&quot;math-container&quot;&gt;$288$&lt;/span&gt;K for &lt;span class=&quot;math-container&quot;&gt;$h=5$&lt;/span&gt; km.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Problems:&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;2a. The height &lt;span class=&quot;math-container&quot;&gt;$h$&lt;/span&gt; is a fudge factor. How do we know from first principles at what altitude the &lt;span class=&quot;math-container&quot;&gt;$255$&lt;/span&gt;K is reached?&lt;/p&gt;&#xA;&lt;p&gt;2b. The &lt;span class=&quot;math-container&quot;&gt;$255$&lt;/span&gt;K temperature is actually reached at four different altitudes in the atmosphere (see figure). Near the top of the troposphere (at &lt;span class=&quot;math-container&quot;&gt;$11$&lt;/span&gt;km) the temperature is &lt;span class=&quot;math-container&quot;&gt;$216$&lt;/span&gt;K, so the &lt;span class=&quot;math-container&quot;&gt;$255$&lt;/span&gt;K at &lt;span class=&quot;math-container&quot;&gt;$5$&lt;/span&gt; kilometres is very much due to atmospheric effects.&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://qph.cf2.quoracdn.net/main-qimg-9a4a2efeb74ce9178bfe65d9b2d458a9&quot; alt=&quot;&quot; /&gt;&lt;/p&gt;&#xA;&lt;p&gt;2c. Lets say we take &lt;span class=&quot;math-container&quot;&gt;$216$&lt;/span&gt;K at the top of the troposphere as a more natural reference point. This still requires justification because it's lower than the &lt;span class=&quot;math-container&quot;&gt;$255$&lt;/span&gt;K, but I guess ozone reduces the UV radiation and hence the effective irradiance that the troposphere receives?&lt;/p&gt;&#xA;&lt;p&gt;2d. Even with a more reasonable reference point, the calculation of the temperature still depends on the lapse rate. The lapse rate is determined by hydrostatic pressure, adiabatic expansion and water vapour (see last reference). I can see how atmospheric composition plays a role via molar properties (of air and water), but it's not obvious where spectral properties come in (absorption etc.). Where does the greenhouse effect feature?&lt;/p&gt;&#xA;&lt;p&gt;2e. The usual logic I've seen is that an increase in greenhouse gases would raise the altitude &lt;span class=&quot;math-container&quot;&gt;$h$&lt;/span&gt; at which &lt;span class=&quot;math-container&quot;&gt;$255$&lt;/span&gt;K is reached, and with a constant lapse rate you get an increase in surface temperature. Again, the whole &lt;span class=&quot;math-container&quot;&gt;$255$&lt;/span&gt;K reference point for the &amp;quot;top of the atmosphere&amp;quot; (actually mid troposphere) is unjustified. Also, I find it odd that a small addition of gases would expand the entire atmosphere (a &lt;span class=&quot;math-container&quot;&gt;$1.1$&lt;/span&gt;K increase means a expansion of the atmosphere by &lt;span class=&quot;math-container&quot;&gt;$170$&lt;/span&gt;m). I find it more likely that the lapse rate would change (from 6.5 to 6.6), which would result in higher surface temperatures.&lt;/p&gt;&#xA;&lt;p&gt;Preferably, I'd like answers to all the questions. But, I know this is a long post so you can just give the right derivation, or point to a definitive reference. Given the topic, I just want to say this is a scientific matter, lets keep it as such. Some sources:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law#Effective_temperature_of_the_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law#Effective_temperature_of_the_Earth&lt;/a&gt;&#xA;&lt;a href=&quot;https://www.acs.org/climatescience/atmosphericwarming/singlelayermodel.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.acs.org/climatescience/atmosphericwarming/singlelayermodel.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.youtube.com/watch?v=hUFOuoD3aHw&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=hUFOuoD3aHw&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://phys.libretexts.org/Bookshelves/Thermodynamics_and_Statistical_Mechanics/Book%3A_Heat_and_Thermodynamics_(Tatum)/08%3A_Heat_Capacity_and_the_Expansion_of_Gases/8.08%3A_Adiabatic_Lapse_Rate&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://phys.libretexts.org/Bookshelves/Thermodynamics_and_Statistical_Mechanics/Book%3A_Heat_and_Thermodynamics_(Tatum)/08%3A_Heat_Capacity_and_the_Expansion_of_Gases/8.08%3A_Adiabatic_Lapse_Rate&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28893" LastActivityDate="2023-05-01T10:35:17.293" Title="Planetary surface temperature from first principles" Tags="|climate-change|climate|temperature|climate-models|planetary-science|" AnswerCount="0" CommentCount="14" ContentLicense="CC BY-SA 4.0" />
  <row Id="25150" PostTypeId="2" ParentId="25146" CreationDate="2023-05-01T12:03:47.607" Score="0" Body="&lt;p&gt;The average adult person emits 0.66kg per day (0.3 Tons per year).&lt;/p&gt;&#xA;&lt;p&gt;Given the current population, 8 billions people, this translates into 2 GTon of CO2 per year.&lt;/p&gt;&#xA;&lt;p&gt;Rough estimates of our impact on the atmoshpere gives our CO2eq emissions at aronud 40 Gton of CO2 per year. 10% of it is therefore directly related to our breathing.&lt;/p&gt;&#xA;&lt;p&gt;Sources: here and reference therein: &lt;a href=&quot;https://www.newscientist.com/lastword/mg25534022-700-what-percentage-of-carbon-dioxide-emissions-is-from-us-breathing-out/#:%7E:text=If%20we%20roughly%20estimate%20that,into%20the%20atmosphere%20each%20year&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.newscientist.com/lastword/mg25534022-700-what-percentage-of-carbon-dioxide-emissions-is-from-us-breathing-out/#:~:text=If%20we%20roughly%20estimate%20that,into%20the%20atmosphere%20each%20year&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2023-05-01T12:03:47.607" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25151" PostTypeId="2" ParentId="25142" CreationDate="2023-05-01T12:34:34.477" Score="2" Body="&lt;p&gt;At a depth of about 1200 km, the temperature can be assumed to be constant, about 5,200° Celsius (9,392° Fahrenheit).&lt;/p&gt;&#xA;&lt;p&gt;At depths between few hundred meters and some kilometers, the temperature is strongly affected by tectonics/groundwater flow, as represented by the heat flow maps.&lt;/p&gt;&#xA;&lt;p&gt;You can however extract some informations from the database of the &lt;a href=&quot;http://ihfc-iugg.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;International Heat Flow Commission (IHFC)&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://ihfc-iugg.org/products&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://ihfc-iugg.org/products&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2023-05-01T12:34:34.477" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25152" PostTypeId="2" ParentId="25087" CreationDate="2023-05-01T12:52:27.097" Score="0" Body="&lt;p&gt;Do your stacking properly. You should not simply sum them, bt since geophysics is a science, please provide a reference for your choice of stacking process.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8zsN0.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8zsN0.gif&quot; alt=&quot;take into account the offset between geophones!&quot; /&gt;&lt;/a&gt;&#xA;(image from here: &lt;a href=&quot;http://www.xsgeo.com/acq.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.xsgeo.com/acq.htm&lt;/a&gt; )&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2023-05-01T12:52:27.097" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25153" PostTypeId="1" CreationDate="2023-05-01T16:48:07.843" Score="2" ViewCount="44" Body="&lt;p&gt;Faults on Earth share a similar displacement/length ratio of around 0.03 which scales from very small faults to very large faults. Would this apply to faults on other planets and if so, are there any examples?&lt;/p&gt;&#xA;" OwnerUserId="27711" LastActivityDate="2023-05-31T18:03:15.383" Title="Displacement-Length scaling relationship on extraterrestrial faults" Tags="|planetary-science|structural-geology|crust|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25154" PostTypeId="1" CreationDate="2023-05-01T16:59:08.413" Score="1" ViewCount="68" Body="&lt;p&gt;I was trying to understand the difference between Drag coefficient C&lt;sub&gt;d&lt;/sub&gt; and Manning's N. There are many sources available online which provide values of Manning's N for different land covers such as Barren land, Developed Land open spaces, Developed Land medium intensity, Barren land, Deciduous Forest etc.&lt;/p&gt;&#xA;&lt;p&gt;My question is:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Are values for Drag Coefficient C&lt;sub&gt;d&lt;/sub&gt; published somewhere for different NLCD land covers? Or Manning's N can be interchangeably used as C&lt;sub&gt;d&lt;/sub&gt; for these land covers?&lt;/li&gt;&#xA;&lt;li&gt;If answer to 1 is No, then given the value of Manning's N how can one calculate the value of Drag coefficient C&lt;sub&gt;d&lt;/sub&gt;?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Thanks in advance for your time.&lt;/p&gt;&#xA;" OwnerUserId="27834" LastEditorUserId="2470" LastEditDate="2023-05-02T06:12:05.577" LastActivityDate="2023-05-02T06:12:05.577" Title="Manning's N vs. Drag Coefficient Cd values for NLCD land cover classes" Tags="|hydrology|fluid-dynamics|runoff|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25155" PostTypeId="2" ParentId="25153" CreationDate="2023-05-01T17:14:48.807" Score="-2" Body="&lt;p&gt;Your assumption is wrong (Lathrop et al., 2022).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8AR5B.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8AR5B.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The image is coming from Lathrop et al (2022) &lt;a href=&quot;https://www.frontiersin.org/articles/10.3389/feart.2022.907543/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;&amp;quot;Displacement/Length Scaling Relationships for Normal Faults; a Review, Critique, and Revised Compilation&amp;quot;&lt;/a&gt; which I invite you to read, for a review on the topic.&lt;/p&gt;&#xA;&lt;p&gt;Said this, it is likely that extraterrestrial fault will have &amp;quot;similar&amp;quot; behavior.&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2023-05-01T17:14:48.807" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25156" PostTypeId="2" ParentId="25154" CreationDate="2023-05-02T06:04:25.287" Score="1" Body="&lt;p&gt;I think you are confusing terminologies.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.fsl.orst.edu/geowater/FX3/help/8_Hydraulic_Reference/Mannings_n_Tables.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Manning N values&lt;/a&gt; are representations of &lt;strong&gt;surface roughness&lt;/strong&gt; that is used in the &lt;a href=&quot;https://www.engineeringtoolbox.com/mannings-formula-gravity-flow-d_800.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Manning equation&lt;/a&gt;, as it is applied to fluid flow in an a open or a closed channel. Basically it's a representation of how rough the walls are of fluid enclosing structures such as: aqueducts, rivers, flood plains, tubes, pipes, tunnels or corridors in buildings (for ventilation purposes, where the fluid is air). Other equations, such as the &lt;a href=&quot;https://mvsengineering.com/files/Subsurface-Book/MVS-SVE_Chapter05.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Atkinson equation&lt;/a&gt; use differing values of &lt;a href=&quot;https://en.wikipedia.org/wiki/Atkinson_resistance&quot; rel=&quot;nofollow noreferrer&quot;&gt;resistance&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Such resistances indicate how the roughness of a channel affects the flow of fluid through the channel.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Drag_coefficient&quot; rel=&quot;nofollow noreferrer&quot;&gt;coefficient of drag&lt;/a&gt; applies to objects &lt;strong&gt;moving in a fluid&lt;/strong&gt;, such as airplanes, rockets, stones thrown and cars moving in air and submarines moving in water, when &lt;em&gt;totally submerged&lt;/em&gt;. Others might say that the coefficient of drag is more about how a fluid moves around an object that is totally immersed in the fluid. It's a matter of perspective. This is totally different to surface roughness of a conveying structure.&lt;/p&gt;&#xA;&lt;p&gt;The skin roughness and the shape of an object and the way it is orientated within a fluid determine its coefficient of drag.&lt;/p&gt;&#xA;&lt;p&gt;Considering only shape, imagine a cone moving through a fluid, such air or water. If the cone is moving so that the pointy end pierces through the fluid the coefficient of drag will be different to the situation where the blunt circular end of the cone pierces the fluid. Similarly, the long side of brick will have a different coefficient of drag to the short end of the brick.&lt;/p&gt;&#xA;&lt;p&gt;If you are trying to look at flow of water over the surface of land and the land surface is covered with boulders and/or shrubs, it is easier consider such objects as elements of the surface roughness, and to use an average roughness value for that section of land, rather than as individual objects for which you need to calculate various coefficients of drag.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-05-02T06:04:25.287" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25157" PostTypeId="1" AcceptedAnswerId="25158" CreationDate="2023-05-02T09:54:11.593" Score="4" ViewCount="313" Body="&lt;p&gt;The &lt;a href=&quot;https://www.bp.com/en/global/corporate/energy-economics/statistical-review-of-world-energy.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;BP Statistical Review of World Energy&lt;/a&gt; provides a lot of interesting data. Personally, I was interested in plotting the energy consumption by source as a function of time for different sources similar to:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/q7Unem.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/q7Unem.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Looking into the BP report, there is for example &lt;strong&gt;Solar Consumption in EJ&lt;/strong&gt; and also &lt;strong&gt;Solar Generation in TWh&lt;/strong&gt;, respectively for each year. I seem to miss something fundamentally here, but why is the first larger than the latter?&lt;/p&gt;&#xA;&lt;p&gt;As an example, take the Solar Consumption in EJ from 2021, which is for the total world 9.73 EJ. This calculates to&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\frac{9.73\cdot10^{18}\,\mathrm{Ws}}{3600\cdot1000} \approx 2701\,\mathrm{TWh}. $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Looking again at the table, the Solar Generation in TWh for 2021 for the total world is 1032.5 TWh, so more than a factor of 2 lower. For me, it would make more sense if it would be the other way. So, obviously, I am missing something fundamental here. Any ideas?&lt;/p&gt;&#xA;" OwnerUserId="28895" LastEditorUserId="6298" LastEditDate="2023-05-02T20:04:46.833" LastActivityDate="2023-05-02T20:04:46.833" Title="Difference between solar consumption and production in BP Review of World Energy" Tags="|energy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25158" PostTypeId="2" ParentId="25157" CreationDate="2023-05-02T11:00:49.450" Score="6" Body="&lt;p&gt;From the first paragraph of the Methodology section:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Primary energy&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Traditionally, in bp’s Statistical Review of World Energy,&#xA;the primary energy of non-fossil based electricity&#xA;(nuclear, hydro, wind, solar, geothermal, biomass&#xA;in power and other renewables sources) has been&#xA;calculated on an ‘input-equivalent’ basis – i.e. based&#xA;on the equivalent amount of fossil fuel input required&#xA;to generate that amount of electricity in a standard&#xA;thermal power plant. For example, if nuclear power&#xA;output for a country was 100 TWh, and the efficiency&#xA;of a standard thermal power plant was 38%, the input-&#xA;equivalent primary energy would be 100/0.38 = 263&#xA;TWh or about 0.95 EJ.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So, they quote the actual solar generation of 1032.5 TWh and the 'input-equivalent' consumption of about 1032.5 / 0.38 = 2717 TWh = 2717 / 278 EJ = 9.77 EJ.  They likely use different efficiencies for different countries depending on the typical thermal plant technologies in each place, in which case their actual global total will be slightly different from these numbers.  I must admit I can't see the Solar Consumption values in the pdf report I'm looking at, presumably you're quoting that number from another table they've provided.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2023-05-02T11:00:49.450" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25159" PostTypeId="1" CreationDate="2023-05-02T13:56:55.630" Score="1" ViewCount="31" Body="&lt;p&gt;Im trying to make netcdf plots like what panoply does but i am not sure how to get this code&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;   vtkSmartPointer&amp;lt;vtkNetCDFCFReader&amp;gt; reader = vtkSmartPointer&amp;lt;vtkNetCDFCFReader&amp;gt;::New();&#xA;    reader-&amp;gt;SetFileName(&amp;quot;C:/Users/admin/Desktop/BOLTgui/BOLT/test.nc&amp;quot;);&#xA;&#xA;    reader-&amp;gt;Update();&#xA;&#xA;    vtkDataObject* dataObject = reader-&amp;gt;GetOutput();&#xA;    vtkDataSet* dataSet = vtkDataSet::SafeDownCast(dataObject);&#xA;    vtkPointData* pointData = dataSet-&amp;gt;GetPointData();&#xA;&#xA;    vtkSmartPointer&amp;lt;vtkContourFilter&amp;gt; contourFilter = vtkSmartPointer&amp;lt;vtkContourFilter&amp;gt;::New();&#xA;    contourFilter-&amp;gt;SetInputConnection(reader-&amp;gt;GetOutputPort());&#xA;    contourFilter-&amp;gt;SetValue(0, 20); // set iso-value&#xA;    contourFilter-&amp;gt;Update();&#xA;&#xA;    vtkSmartPointer&amp;lt;vtkLookupTable&amp;gt; lookupTable = vtkSmartPointer&amp;lt;vtkLookupTable&amp;gt;::New();&#xA;    lookupTable-&amp;gt;SetNumberOfTableValues(256);&#xA;    lookupTable-&amp;gt;Build();&#xA;    lookupTable-&amp;gt;SetTableRange(contourFilter-&amp;gt;GetOutput()-&amp;gt;GetScalarRange());&#xA;&#xA;    vtkSmartPointer&amp;lt;vtkColorTransferFunction&amp;gt; colorTransferFunction = vtkSmartPointer&amp;lt;vtkColorTransferFunction&amp;gt;::New();&#xA;    colorTransferFunction-&amp;gt;AddRGBPoint(0.0, 0.0, 0.0, 1.0); // blue&#xA;    colorTransferFunction-&amp;gt;AddRGBPoint(20.0, 0.0, 1.0, 0.0); // green&#xA;    colorTransferFunction-&amp;gt;AddRGBPoint(40.0, 1.0, 1.0, 0.0); // yellow&#xA;    colorTransferFunction-&amp;gt;AddRGBPoint(60.0, 1.0, 0.0, 0.0); // red&#xA;&#xA;    vtkSmartPointer&amp;lt;vtkPolyDataMapper&amp;gt; mapper = vtkSmartPointer&amp;lt;vtkPolyDataMapper&amp;gt;::New();&#xA;    mapper-&amp;gt;SetInputConnection(contourFilter-&amp;gt;GetOutputPort());&#xA;    mapper-&amp;gt;SetLookupTable(lookupTable);&#xA;    mapper-&amp;gt;UseLookupTableScalarRangeOn();&#xA;&#xA;    mapper-&amp;gt;ScalarVisibilityOn();&#xA;    mapper-&amp;gt;SetScalarModeToUsePointData();&#xA;    mapper-&amp;gt;SetLookupTable(lookupTable);&#xA;    mapper-&amp;gt;SetLookupTable(colorTransferFunction);&#xA;&#xA;    vtkSmartPointer&amp;lt;vtkActor&amp;gt; actor = vtkSmartPointer&amp;lt;vtkActor&amp;gt;::New();&#xA;    actor-&amp;gt;SetMapper(mapper);&#xA;&#xA;    vtkSmartPointer&amp;lt;vtkRenderer&amp;gt; renderer = vtkSmartPointer &amp;lt; vtkRenderer&amp;gt;::New();&#xA;    renderer-&amp;gt;AddActor(actor);&#xA;&#xA;    vtkSmartPointer&amp;lt;vtkRenderWindow&amp;gt; renderWindow = vtkSmartPointer&amp;lt;vtkRenderWindow&amp;gt;::New();&#xA;    renderWindow-&amp;gt;AddRenderer(renderer);&#xA;&#xA;    vtkSmartPointer&amp;lt;vtkRenderWindowInteractor&amp;gt; interactor = vtkSmartPointer&amp;lt;vtkRenderWindowInteractor&amp;gt;::New();&#xA;    interactor-&amp;gt;SetRenderWindow(renderWindow);&#xA;&#xA;    sf::WindowHandle handle = window.getSystemHandle();&#xA;    renderWindow-&amp;gt;SetWindowInfo(reinterpret_cast&amp;lt;char*&amp;gt;(handle));&#xA;    interactor-&amp;gt;Start();&#xA;   //While loop&#xA;       glBegin(GL_TRIANGLES);&#xA;        glPointSize(0.111f);&#xA;&#xA;        // Calculate scaling factor&#xA;        float scalingFactor = 1.0f / 2.111f;&#xA;&#xA;        vtkSmartPointer&amp;lt;vtkDataSet&amp;gt; data = vtkDataSet::SafeDownCast(reader-&amp;gt;GetOutput());&#xA;        for (vtkIdType i = 0; i &amp;lt; data-&amp;gt;GetNumberOfCells(); i++) {&#xA;            vtkCell* cell = data-&amp;gt;GetCell(i);&#xA;            vtkPoints* points = cell-&amp;gt;GetPoints();&#xA;            double point1[3];&#xA;            double point2[3];&#xA;            double point3[3];&#xA;            points-&amp;gt;GetPoint(0, point1);&#xA;            points-&amp;gt;GetPoint(1, point2);&#xA;            points-&amp;gt;GetPoint(2, point3);&#xA;            // Set the color for the first vertex&#xA;            glColor3f(1.0f, 0.0f, 0.0f);&#xA;            // Scale the point coordinates to adjust the size&#xA;            glVertex3f(point1[0] * scalingFactor, point1[1] * scalingFactor, point1[2] * scalingFactor);&#xA;            // Set the color for the second vertex&#xA;            glColor3f(0.0f, 1.0f, 0.0f);&#xA;            glVertex3f(point2[0] * scalingFactor, point2[1] * scalingFactor, point2[2] * scalingFactor);&#xA;            // Set the color for the third vertex&#xA;            glColor3f(0.0f, 0.0f, 1.0f);&#xA;            glVertex3f(point3[0] * scalingFactor, point3[1] * scalingFactor, point3[2] * scalingFactor);&#xA;        }&#xA;        glEnd();&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;this code currently displays the netcdf data like this  &lt;a href=&quot;https://i.stack.imgur.com/GdVrR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GdVrR.png&quot; alt=&quot;like this&quot; /&gt;&lt;/a&gt;&#xA;but i am trying to render the netcdf data in opengl like this &lt;a href=&quot;https://i.stack.imgur.com/OKtd6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OKtd6.png&quot; alt=&quot;like this panoply plot&quot; /&gt;&lt;/a&gt;&#xA;what do i need to do to modify the code to render the netcdf data like in the panoply plot&lt;/p&gt;&#xA;" OwnerUserId="26704" LastActivityDate="2023-05-02T13:56:55.630" Title="How to make netcdf plots like panoply in C++" Tags="|netcdf|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25161" PostTypeId="1" CreationDate="2023-05-02T18:21:13.797" Score="2" ViewCount="63" Body="&lt;p&gt;I'm trying to better understand why I see so many people pick a fixed value of &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; in Glen's Flow law when doing glacier modeling. I found that using a simple Arrhenius relationship we get the formula&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$A(T) = \left( A_0 exp\left(\frac{-Q}{R(T- \beta P)}\right) \right)$&lt;/span&gt;   (from page 12 of &lt;a href=&quot;https://www.researchgate.net/publication/267748557_Simulating_the_climatic_response_of_Hardangerjokulen_in_southern_Norway_since_the_Little_Ice_Age_Master%27s_thesis_in_Earth_Science&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; source)&lt;/p&gt;&#xA;&lt;p&gt;This formula would imply that temperature affects the value of &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; so I would think that there would be a different &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; at different depths within the glacier. However, I've also found out that we don't usually have temperature data at different depths within a glacier. This indicates to me that we can't use the above function to calculate &lt;span class=&quot;math-container&quot;&gt;$A(T)$&lt;/span&gt; at different depths within the glacier.&lt;/p&gt;&#xA;&lt;p&gt;This &lt;a href=&quot;https://glaciers.gi.alaska.edu/sites/default/files/Notes_thermodynamics_Aschwanden.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt; (page 1) makes it seem like we just pick a type of thermal structure for the glacier at hand (cold, temperate, or polythermal) and then use that to determine what constant we should pick for &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Why is fixing &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; to be a constant seen as an accurate approach if &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; depends so heavily on temperature? Does the thermal structure for the glacier at hand (cold, temperate, or polythermal) really give us enough information to accurately fix &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; to be a constant value?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Any authors or key phrases to look into for more information on this would be appreciated.&lt;/p&gt;&#xA;&lt;p&gt;Any information is greatly appreciated. I'm very new to this.&lt;/p&gt;&#xA;" OwnerUserId="28536" LastEditorUserId="28536" LastEditDate="2023-05-04T00:07:45.257" LastActivityDate="2023-06-04T15:06:10.677" Title="Understanding Temperature's Effect on Glen's Flow Rate Factor A = A(T) and Why we Take A = Constant" Tags="|climate-models|glaciology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25163" PostTypeId="1" CreationDate="2023-05-04T14:25:07.293" Score="3" ViewCount="73" Body="&lt;p&gt;Sulfur oxides have a strong but short lasting athmosheric cooling effect. Vulcanic eruptions provide test of that. Lignite or &amp;quot;brown coal&amp;quot; has a reputaion as a paricularly &amp;quot;dirty&amp;quot; fuel, not least for its very high sulfur content.&#xA;Now, for estimations of &amp;quot;climate footprint&amp;quot;, the numbers given for methane seem to imply that atmosheric breakdown/washout time does not matter much.&#xA;So what is the climate footprint of burning lignite, including the effect of sulfur pollution?&lt;/p&gt;&#xA;" OwnerUserId="10751" LastActivityDate="2023-05-06T13:22:39.773" Title="What is the climate footprint of burning lignite coal - once you account for the athmosheric cooling effect of sulfur dioxide?" Tags="|atmosphere|climate-models|climatology|greenhouse-gases|coal|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25165" PostTypeId="1" CreationDate="2023-05-05T09:21:47.557" Score="1" ViewCount="148" Body="&lt;p&gt;Are mud cracks formed during rock formation or after the rock is completely formed?&lt;a href=&quot;https://i.stack.imgur.com/OvFuy.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OvFuy.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28655" LastEditorUserId="28655" LastEditDate="2023-05-05T09:22:17.543" LastActivityDate="2023-06-05T13:05:40.690" Title="Mud cracks formation" Tags="|geology|rocks|structural-geology|stratigraphy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25166" PostTypeId="1" CreationDate="2023-05-05T09:36:29.360" Score="1" ViewCount="15" Body="&lt;p&gt;Consider two groups of glaciers, say Group A and Group B. For simplicity, let's consider the group to fall in one size class (say 1-5 sq km), both located in the same kind of climate. We DO NOT know the elevation (let's assume). If I have the retreat of Group A to be higher than Group B for the same period under warming temperatures, does that mean Group A is more sensitive to climate forcing?&lt;/p&gt;&#xA;" OwnerUserId="28184" LastActivityDate="2023-05-05T09:36:29.360" Title="What determines and confirms sensitivity of glaciers to climate change/ climate forcing?" Tags="|climate-change|glaciology|climatology|glaciation|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25167" PostTypeId="2" ParentId="25161" CreationDate="2023-05-05T14:39:00.620" Score="1" Body="&lt;p&gt;Glen's flow law is an empirical law derived from both field and experimental data (Glen 1955). In its original form Glen expressed the law as&#xA;&lt;span class=&quot;math-container&quot;&gt;$$&#xA;\dot\varepsilon = B \exp{(-Q/RT)}\sigma^n&#xA;$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$\dot\varepsilon$&lt;/span&gt; is the deformation rate, &lt;span class=&quot;math-container&quot;&gt;$B$&lt;/span&gt; &lt;span class=&quot;math-container&quot;&gt;$Q$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$n$&lt;/span&gt; are empirical constants, &lt;span class=&quot;math-container&quot;&gt;$R$&lt;/span&gt; is the gas constant and &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; is the absolute temperature.&#xA;This formulation introduces a temperature dependence on the deformation.&lt;/p&gt;&#xA;&lt;p&gt;The empirical constant &lt;span class=&quot;math-container&quot;&gt;$n$&lt;/span&gt; is commonly taken as being &lt;span class=&quot;math-container&quot;&gt;$=3$&lt;/span&gt; but this is basically an average of various experimental results. Goldsby (2009) showed that &lt;span class=&quot;math-container&quot;&gt;$n$&lt;/span&gt; can be both smaller and larger depending if the stresses are very low or very high, respectively. Millstein et al. (2022) show that the stress dependence may be even larger than previously thought with &lt;span class=&quot;math-container&quot;&gt;$n\approx 4.1$&lt;/span&gt; in fast flowing areas of ice sheets.&lt;/p&gt;&#xA;&lt;p&gt;The viscosity parameter &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; (&lt;span class=&quot;math-container&quot;&gt;$B$&lt;/span&gt; in Glen's notation) will vary with ice temperature as seen above. However, the viscosity parameter is also sensitive to several other parameters such as pressure, crystal size and shape, crystal orientation, impurities in the ice (Gow and Williamson 1976, Hooke 1981, Alley 1992). Hence the viscosity parameter can be seen as site specific.&lt;/p&gt;&#xA;&lt;p&gt;Clearly the value of B may be impossible to predict unless a wealth of information is known about the glacier ice throughout its body. So one way do deal with this is to use the viscosity parameter as a tuning parameter. Usually this involves comparing model output with measured velocities. This approach has been implemented in many different ways by modellers of glaciers and ice sheets. In models with a thermodynamic component the flow law may still include a temperature dependence.&lt;/p&gt;&#xA;&lt;p&gt;In the review by Hooke (1981) it also seems clear that laboratory and field experiments yielding the empirical constants &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$n$&lt;/span&gt; diverge. One reason for this is that small laboratory specimens of ice yield values that are not fully representative of natural conditions.&lt;/p&gt;&#xA;&lt;p&gt;So, the final comment is that using a single value of A is a last resort when the complexity of the natural ice cannot be accommodated in calculations or models. The value of &lt;span class=&quot;math-container&quot;&gt;$A$&lt;/span&gt; is still site specific and not generally transferable between glaciers or sites on glaciers. In the end the use of solution for the flow law depends on what is &amp;quot;good enough&amp;quot; for the problem to be solved.&lt;/p&gt;&#xA;&lt;p&gt;References&lt;/p&gt;&#xA;&lt;p&gt;Alley R, 1992. Flow-law hypotheses for ice-sheet modeling. Journal of Glaciology, 38(129), 245-256. doi:10.3189/S0022143000003658&lt;/p&gt;&#xA;&lt;p&gt;Glen JW, 1955. The creep of polycrystalline ice. Proceedings of the&#xA;Royal Society, Series A228 519–538. &lt;a href=&quot;https://doi.org/10.1098/rspa.1955.0066&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1098/rspa.1955.0066&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Goldsby D, 2009. Superplastic flow of ice relevant to glacier and ice-sheet&#xA;mechanics. In Knight P, (ed.) Glacier Science and Environmental Change. Oxford: Wiley-Blackwell, 527pp. &lt;a href=&quot;https://doi.org/10.1002/9780470750636.ch60&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1002/9780470750636.ch60&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Gow AJ and Williamson T, 1976. Rheological implications of the internal structure and crystal fabrics of the West Antarctic ice sheet as revealed by deep core drilling at Byrd Station. Geological Society of America Bulletin, 87,&#xA;1665–1677.&lt;/p&gt;&#xA;&lt;p&gt;Hooke RLeB, 1981. Flow law for polycrystalline ice in glaciers: comparison of theoretical predictions, laboratory data, and field measurements. Reviews of Geophysics and Space Physics, 19(4), 664–672. &lt;a href=&quot;https://doi.org/10.1029/RG019i004p00664&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1029/RG019i004p00664&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Millstein JD, Minchew BM and Pegler SS, 2022. Ice viscosity is more sensitive to stress than commonly assumed. Commun Earth Environ 3, 57. &lt;a href=&quot;https://doi.org/10.1038/s43247-022-00385-x&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1038/s43247-022-00385-x&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="81" LastActivityDate="2023-05-05T14:39:00.620" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25168" PostTypeId="1" CreationDate="2023-05-06T10:34:42.277" Score="1" ViewCount="35" Body="&lt;p&gt;Do seismographs become more complex (waves of different frequencies superimposed on one another) for higher magnitude earthquakes where I am guessing there would be a larger variety and number of cracks in stressed rocks for these earthquakes with more energy. If a seismograph becomes more complex for a given location over a number of months could this help predict large earthquakes?&lt;/p&gt;&#xA;" OwnerDisplayName="user28909" LastActivityDate="2023-05-06T10:34:42.277" Title="When rock cracks at tectonic plate boundaries are the number and size of cracks reflected in seismographs?" Tags="|earthquakes|seismology|predictability|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25169" PostTypeId="2" ParentId="25165" CreationDate="2023-05-06T12:09:20.177" Score="1" Body="&lt;p&gt;Mud cracks are created at the surface of mud, as the name implies.&#xA;Afterwards, due to burial processes, younger sediments may fill in the cracks.&lt;/p&gt;&#xA;&lt;p&gt;Later, the mud-cracked-with-infilled-sediments system will lithify, as visible in this nice vertical section of an infilled mud-crack &lt;a href=&quot;https://en.wikipedia.org/wiki/Mudcrack#/media/File:Mudcracks_mcr3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;the photo is made by Michael C. Rygel and is accessible via Wikimedia Commons of &lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2023-05-06T12:09:20.177" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25170" PostTypeId="2" ParentId="25163" CreationDate="2023-05-06T13:22:39.773" Score="3" Body="&lt;p&gt;Sulfur dioxide, as such, does not cool the atmosphere. The cooling comes about when the sulfur dioxide is oxidized in the presence of moisture to produce dilute sulfuric acid in the form of aerosol; reflection of solar radiation from the aerosol is what then cools the planet.&lt;/p&gt;&#xA;&lt;p&gt;It's not a good bargain ecologically. The sulfuric acid is a major culprit in acid rain, and sulfur emissions do &lt;a href=&quot;https://www.epa.gov/acidrain/effects-acid-rain&quot; rel=&quot;nofollow noreferrer&quot;&gt;great harm to ecological systems&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The sulfur content in lignite coal is not all that high. Compared with bituminous coal, lignite actually has about the same or less sulfur per unit of energy output. See the table below from Ref. [&lt;a href=&quot;https://i.stack.imgur.com/uaKMn.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;](&lt;a href=&quot;https://doi.org/10.1016/j.coal.2019.103336&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/j.coal.2019.103336&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/uaKMn.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uaKMn.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Julia Kagiliery, Somsubhra Chakraborty, Autumn Acree, David C. Weindorf, Eric C. Brevik, Nicolas A. Jelinski, Bin Li, Cynthia Jordan (2019).&#xA;&amp;quot;Rapid quantification of lignite sulfur content: Combining optical and X-ray approaches&amp;quot;. &lt;em&gt;International Journal of Coal Geology&lt;/em&gt;&#xA;&lt;strong&gt;216&lt;/strong&gt;, 103336.&#xA;ISSN 0166-5162,&#xA;&lt;a href=&quot;https://doi.org/10.1016/j.coal.2019.103336&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/j.coal.2019.103336&lt;/a&gt;.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2023-05-06T13:22:39.773" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25171" PostTypeId="1" AcceptedAnswerId="25178" CreationDate="2023-05-07T10:13:54.223" Score="4" ViewCount="68" Body="&lt;p&gt;Equivalent Potential Temperature, defined as&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\theta_e = \theta \cdot e^{qL/c_pT}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;with &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; denoting potential temperature and q the specific moisture of water remains constant for wet adiabatic processes. Does it make sense to assign it also to unsaturated air parcels? Lets say, an an unsaturated parcel is lifted to LCL, where condensation starts. Is &lt;span class=&quot;math-container&quot;&gt;$\theta_e$&lt;/span&gt; constant during this dry adiabatic process too? I'm not sure, but I would say, that T must be replaced by the T', at which condensation occur - otherwise it makes no sense.&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2023-05-07T10:59:39.243" LastActivityDate="2023-05-10T07:19:20.620" Title="Is equivalent potential temperature constant also for dry adiabatic processes?" Tags="|meteorology|atmosphere|temperature|atmosphere-modelling|thermodynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25172" PostTypeId="1" AcceptedAnswerId="25175" CreationDate="2023-05-07T13:37:37.740" Score="4" ViewCount="65" Body="&lt;p&gt;Rupes Recta is a 110km long normal fault on the Lunar nearside. It appears to contain features that resemble terrestrial &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Transfer_zone#Interbasin_transfer_zones&quot; rel=&quot;nofollow noreferrer&quot;&gt;relay ramps&lt;/a&gt;. Is this the case or is it something else?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/q2k13.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/q2k13.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27711" LastEditorUserId="6298" LastEditDate="2023-05-09T20:16:28.553" LastActivityDate="2023-05-09T20:16:28.553" Title="Relay structures in Rupes Recta" Tags="|structural-geology|tectonics|moon|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25174" PostTypeId="1" CreationDate="2023-05-07T19:35:19.240" Score="3" ViewCount="125" Body="&lt;p&gt;I'm posting here for the first time, so I hope not to violate any community-specific rules.&lt;/p&gt;&#xA;&lt;p&gt;In &lt;a href=&quot;https://www.fao.org/3/x0490e/x0490e07.htm#radiation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Allen et al. (1998): FAO-56&lt;/a&gt; an equation is presented to estimate extraterrestrial radiation Ra for different latitudes from the solar constant, the solar declination and the time of the year:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NtXM8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NtXM8.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This works quite well to replicate most of the pre-computed values given in &lt;a href=&quot;https://www.fao.org/3/X0490E/x0490e0j.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Annnex 2, table 2.6&lt;/a&gt; - except for the values in the 70-deg-lat row.&lt;/p&gt;&#xA;&lt;p&gt;I already noticed the computation fails at this point because of the sunset hour angle equation for latitudes &amp;gt; 66.5° N/S, where you end up with &lt;code&gt;-tan(phi) * tan(delta) &amp;gt; 1&lt;/code&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9EpnD.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9EpnD.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;While FAO-56 does not seem to mention any restrictions or alternative equations, &lt;a href=&quot;https://swat.tamu.edu/media/99192/swat2009-theory.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Neitsch et al. (2011): SWAT Theoretical Documentation&lt;/a&gt; at least mention the following (p. 32):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;At latitudes above 66.5° or below -66.5°, the absolute value of &lt;code&gt;-tan(phi) * tan(delta)&lt;/code&gt; can&#xA;exceed 1 and the above equation cannot be used.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Maybe I'm just lacking some basic math knowledge to notice the obvious for a workaround, but from my point of view the limitation makes sense insofar, as there can't be a sunset hour angle by definition if there is no sunset during certain times of the year.&lt;/p&gt;&#xA;&lt;p&gt;However, I guess another equation might be applicable in this case in order to determine Ra for high latitudes which I'm not aware of yet?&lt;/p&gt;&#xA;&lt;p&gt;Thank you very much in advance!&lt;/p&gt;&#xA;" OwnerUserId="27436" LastActivityDate="2023-05-07T19:35:19.240" Title="Estimation of extraterrestrial radiation for latitudes &gt; 66.5° N/S" Tags="|meteorology|atmospheric-radiation|insolation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25175" PostTypeId="2" ParentId="25172" CreationDate="2023-05-08T12:23:49.067" Score="4" Body="&lt;p&gt;From &lt;a href=&quot;https://doi.org/10.1144/SP401.4&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nahm &amp;amp; Schultz (2013)&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Detailed structural mapping of Rupes Recta has revealed the presence of four distinct fault segments (Fig. 6). Analysis of throw distributions can clarify which segments are mechanically linked and which segments are separated by relay ramps (Peacock &amp;amp; Sanderson 1991).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Later:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Faults grow through this mechanism in three stages (Peacock &amp;amp; Sanderson 1991): isolated faults propagate towards each other and eventually interact when their tips are close and/or overlapping. The fault segments may continue to grow without direct linkage of segments (soft linkage), forming relay ramps, or link by breaching relay ramps and mechanically linking (hard linkage).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;and finally:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The growth of segments within a narrow linear zone implies that Rupes Recta formed at depth and propagated up to the lunar surface. As the segments grew towards each other, relay ramps formed at boundaries A–D, visible in imagery (Fig. 6). Displacement continued to accumulate, and relay ramps at B and C were breached, hard-linking the segments together.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Unfortunately, I cannot reproduce their figure 6 here because of copyright, but the four segment boundaries they identified on it, named A, B, C, and D, correspond to the ones you circled, from top to bottom (A and B are both in the top circle). The authors interpret A and D as relay ramps, and B and C as breached relay ramps.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="6298" LastEditDate="2023-05-09T20:09:28.457" LastActivityDate="2023-05-09T20:09:28.457" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25176" PostTypeId="2" ParentId="8181" CreationDate="2023-05-08T19:08:00.840" Score="4" Body="&lt;p&gt;I'm guessing that hydrogen sulfide was not intended as the direct reason for being 'Under a Green Sky', either in the Proterozoic between Huronian and Cryogenian glaciations, or in Phanerozoic extinctions.&lt;/p&gt;&#xA;&lt;p&gt;The suggested process of the Permian-Triassic extinction in particular is summarised in &lt;a href=&quot;https://phys.org/news/2005-02-global-atmospheric-hydrogen-sulfide-permian.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this 2005 article&lt;/a&gt; based on Kump et al, and &lt;a href=&quot;https://phys.org/news/2010-12-day-algae-died.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;this 2010 follow-up&lt;/a&gt;.  Peter Ward's book was published in 2008, while Kump's finding of ozone layer collapse was being reevaluated by &lt;a href=&quot;https://doi.org/10.1029/2006GL028384&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lamarque et al (2007, open access)&lt;/a&gt; and  &lt;a href=&quot;https://doi.org/10.1038/ngeo154&quot; rel=&quot;nofollow noreferrer&quot;&gt;Harfoot et al (2008)&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The Boring Billion atmosphere was not as oxidising as today, while the suggested P-T emissions of methane from geological processes, ocean die-off and accelerated decomposition may have overwhelmed atmospheric hydroyxl reactions, even if it did not greatly increase ultraviolet reaching the surface. (Ozone supposedly contributes slightly to blue sky colour when the Sun is at a low elevation, but this is not a major factor.  The main cause for a blue sky is well-known to be single Rayleigh scattering and this would be unchanged.)&lt;/p&gt;&#xA;&lt;p&gt;So a less oxidising atmosphere might not be pink, as James Lovelock thought the Archaean might have been, but still laden with significant amounts of hydrocarbons and reddish tholins. UV would increase production of tholins, but may not be necessary. Other factors increasing lightness and decreasing chroma might include volcanic aerosols and sulphates from oxidisation of tropospheric H₂S; and in the Proterozoic one might expect colour from frequent dust storms, unimpeded by any complex life on land, also absorbing blue light.&lt;/p&gt;&#xA;&lt;p&gt;There is good evidence for widespread volcanism, high CO₂, warming, &lt;a href=&quot;https://doi.org/10.1126/science.aat1327&quot; rel=&quot;nofollow noreferrer&quot;&gt;anoxia&lt;/a&gt; and euxinia shortly before or during Palaeozoic extinctions. The high level of sulfides may have killed off many species even if it didn't kill off the ozone layer.&lt;/p&gt;&#xA;" OwnerUserId="28922" LastEditorUserId="2470" LastEditDate="2023-05-10T05:56:55.520" LastActivityDate="2023-05-10T05:56:55.520" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25177" PostTypeId="1" CreationDate="2023-05-09T03:50:05.530" Score="6" ViewCount="36" Body="&lt;p&gt;I am finding it difficult to understand the factors that affect the suspended sediment yield in an area. I was thinking of the Rouse number and how it is affected by the particle diameter, slope and flow depth. Although I could not correlate a suspended sediment yield with the vegetation cover, soil type and rainfall intensity. Could someone give an example where an area will contain high suspended sediment yield and what the properties of this area are going to be?&lt;/p&gt;&#xA;" OwnerUserId="27553" LastEditorUserId="2470" LastEditDate="2023-05-10T05:57:39.053" LastActivityDate="2023-05-18T18:43:07.797" Title="Suspended sediment yield" Tags="|geology|sedimentology|vegetation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25178" PostTypeId="2" ParentId="25171" CreationDate="2023-05-10T07:19:20.620" Score="2" Body="&lt;p&gt;Yes. Since the later term doesn't change during dry adiabatic processes and the former neither, the equivalent potential temperature &lt;span class=&quot;math-container&quot;&gt;$\theta_e$&lt;/span&gt; does also stay constant for dry adiabatic processes.&#xA;Whether it makes sense to &amp;quot;assign&amp;quot; (maybe you meant &amp;quot;measure&amp;quot;) it to unsaturated air parcels depends on the application.&lt;/p&gt;&#xA;" OwnerUserId="28529" LastActivityDate="2023-05-10T07:19:20.620" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25179" PostTypeId="1" CreationDate="2023-05-10T15:54:26.173" Score="1" ViewCount="36" Body="&lt;p&gt;I'm working with a bunch of netCDF files for uni, hence the &lt;code&gt;for loop&lt;/code&gt;. Its global coverage data, and because the Earth is not flat, we need to weight the pixels/grid cells of the data to make sure we have an accurate value for the mean (otherwise certain points that take up way more area i.e. near the poles, will contribute more the the mean than they should). What I am trying to do here is first weight each pixel, then get the spatial average of the variable, here called 'var'. Here is my code for it:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;    for filename in os.listdir(indir): # indir = /path/to/directoy&#xA;        input_file = os.path.join(indir, filename)&#xA;        output_file = os.path.join(outdir, filename) # outdir = /path/to/directoy&#xA;        ds = xr.open_dataset(input_file)&#xA;  &#xA;        R = 6.371e6  # radius of Earth in m&#xA;        dphi=np.deg2rad(2.5) # degs between lat, in metadata of ds&#xA;        dlambda = np.deg2rad(2.5) # degrees between lons &#xA;&#xA;        dlat = R * dphi*xr.ones_like(ds.var.lon)&#xA;        dlon = R * dlambda*np.cos(np.deg2rad(ds.var.lat))&#xA;        cell_area = dlon*dlat&#xA;&#xA;        da_area = cell_area.broadcast_like(ds.var) # to get to same shape as ds&#xA;        total_area=da_area.sum(['lat','lon'])&#xA;        ds_weighted = ((ds['var']*da_area)/total_area)&#xA;&#xA;        fldmean = ds_weighted.mean(dim=['lat', 'lon'], skipna=True)&#xA;        fldmean.to_netcdf(output_file)&#xA;        ds.close()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Its based on &lt;a href=&quot;https://towardsdatascience.com/the-correct-way-to-average-the-globe-92ceecd172b7&quot; rel=&quot;nofollow noreferrer&quot;&gt;this example&lt;/a&gt;. I also tried to keep the names here as simple as possible, hence they are pretty generic.&lt;/p&gt;&#xA;&lt;p&gt;I don't get any errors when I run it, and it saves just fine where I need it to. The resulting time series plot also looks good - but the values are tiny, like 2.4743e-6, where I am expecting somewhere between 5 and 15, so its many magnitudes out. For the life of me, I can't see what is so different here to the example in the link. I guess it must be something to do with the divide to get such small numbers, but its also how its done in the link and also makes some logical sense. Any ideas?&lt;/p&gt;&#xA;&lt;p&gt;footnote: This is also 'area weighting' rather than 'latitude weighting', this is because I'm trying to do a comparison with the &lt;code&gt;fldmean&lt;/code&gt; function in CDO (Climate Data Operators), which uses area weighting. I'm still getting my head around if it makes much difference, but I still want to stay as close as possible to this operator!&lt;/p&gt;&#xA;" OwnerUserId="28930" LastEditorUserId="2470" LastEditDate="2023-05-11T01:21:56.710" LastActivityDate="2023-05-11T01:21:56.710" Title="Why does this method for weighting grid cells result in tiny values?" Tags="|python|netcdf|grid-spacing|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25180" PostTypeId="2" ParentId="22784" CreationDate="2023-05-10T19:18:14.733" Score="1" Body="&lt;h3&gt;Surface Displacement vs. Earthquake Magntidue&lt;/h3&gt;&#xA;&lt;p&gt;This answer presumes that you are looking for a relationship between earthquake displacement and earthquake magnitude. I think what you are looking for the following:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nASpv.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nASpv.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;From Wells and Coppersmith, 1994. This is a well cited, though still controversial reference. &lt;a href=&quot;https://pubs.geoscienceworld.org/ssa/bssa/article/84/4/974/119792/New-empirical-relationships-among-magnitude&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://pubs.geoscienceworld.org/ssa/bssa/article/84/4/974/119792/New-empirical-relationships-among-magnitude&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;So yes, there is some relationship between displacement and earthquake magnitude, albeit with a lot of uncertainty.&lt;/p&gt;&#xA;&lt;h2&gt;Some important notes and caveats&lt;/h2&gt;&#xA;&lt;p&gt;The word deformation carries a broader meaning than displacement. Deformation describes spatial gradients of displacement everywhere, not just on a fault. Displacement has a more specific definition: the relative motion measured in meters, for example, across a fault.&lt;/p&gt;&#xA;&lt;p&gt;This relationship above is averaging displacement over the fault. So it may not be easy to reconstruct a magnitude from a single observation in the geological record.&lt;/p&gt;&#xA;&lt;p&gt;It can be difficult or impossible to know from the geological record whether displacement occured in a single earthquake or many. Relatedly, not all fault displacement results in an earthquake.&lt;/p&gt;&#xA;&lt;p&gt;The is some physical basis for these relationships related to the definition of earthquake moment in terms of fault displacement, area and shear modulus. You can refer to Kanamori and Anderson, 1975 for a very good (albeit detailed) explanation: &lt;a href=&quot;https://pubs.geoscienceworld.org/ssa/bssa/article/84/4/974/119792/New-empirical-relationships-among-magnitude&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://pubs.geoscienceworld.org/ssa/bssa/article/84/4/974/119792/New-empirical-relationships-among-magnitude&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="6245" LastActivityDate="2023-05-10T19:18:14.733" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25181" PostTypeId="1" CreationDate="2023-05-10T19:27:09.707" Score="2" ViewCount="37" Body="&lt;p&gt;So I know that cloud tops of the thunderstorm in a tropical cyclone can reach -80 degrees Celsius according to infrared satellite imagery. Is the temperature of the air above the storm's eyewall different from the cloud top temperature?&lt;/p&gt;&#xA;&lt;p&gt;I saw &lt;a href=&quot;https://www.researchgate.net/profile/Guido-Cioni/publication/301790577/figure/fig1/AS:357634168377353@1462278038980/The-Hurricane-Carnot-cycle-the-colors-depict-entropy-distribution-blue-green.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;this diagram&lt;/a&gt; which shows the carnot cycle inside a tropical cyclone. Point B to C is the adiabatic expansion part while C to D is the isothermal compression part. It seems that, from the diagram, the -75 degrees Celsius area is only from point C to D. The area above the eyewall seems very warm due to the latent heat release from the condensation of water vapor.&lt;/p&gt;&#xA;&lt;p&gt;Or is the chart showing equivalent potential temperature? Does that mean the temperature above the eyewall is still around -75 degrees Celsius? All the temperature profiles I've seen of a tropical cyclone uses equivalent potential temperature and not actual temperature.&lt;/p&gt;&#xA;" OwnerUserId="28809" LastActivityDate="2023-05-10T19:27:09.707" Title="Is it cold or hot on top of a tropical cyclone?" Tags="|temperature|clouds|tropical-cyclone|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25182" PostTypeId="1" CreationDate="2023-05-11T07:37:43.183" Score="1" ViewCount="26" Body="&lt;p&gt;As I understand, for elevation mapping using InSAR, one typically requires an out-of-plane baseline to create the required phase difference between images to detect objects at height. This usually requires either multiple satellites flying in formation or waiting for a repeat pass of a single satellite.&lt;/p&gt;&#xA;&lt;p&gt;This paper, &lt;a href=&quot;https://www.mdpi.com/2072-4292/11/9/1070&quot; rel=&quot;nofollow noreferrer&quot;&gt;A New Single-Pass SAR Interferometry Technique with a Single-Antenna for Terrain Height Measurements&lt;/a&gt;, suggests that one could achieve this in a single pass (along-track interferometry), if we are able to image at a high squint angle. The idea is that a grazing-angle difference is still present in the along-track case when squint angle is high. This is not the case for broadside imaging.&lt;/p&gt;&#xA;&lt;p&gt;However apart from this paper, I was not able to find any other sources to cross-reference the viability of this approach, nor does it seem that anyone else has reproduced the results. The mathematical principle behind seem sound to me. If it works, why is this concept not being used more often, and if it doesn't actually work, where is the error in the logic?&lt;/p&gt;&#xA;" OwnerUserId="28932" LastEditorUserId="18088" LastEditDate="2023-05-12T03:32:50.840" LastActivityDate="2023-05-12T03:32:50.840" Title="Single-Antenna-Single-Pass SAR interferometry" Tags="|remote-sensing|radar|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25183" PostTypeId="1" AcceptedAnswerId="25184" CreationDate="2023-05-11T23:32:29.137" Score="2" ViewCount="160" Body="&lt;p&gt;When confronting people with this question, I often get back something along the lines of &amp;quot;the higher the latitude, the smaller/wider the angle at which the sun hits the surface. As a result the same energy is spread across a larger surface, causing the insolation (W/m^2) to be lower at higher latitudes.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;See image below. (This is basically the explanation for why temperatures tend to be higher at the equator.)&lt;/p&gt;&#xA;&lt;p&gt;But isn't the angle of the sun &amp;quot;corrected for&amp;quot; by simply placing the panels at the right angle?&lt;/p&gt;&#xA;&lt;p&gt;If that is indeed the case, then what is the real reason why solar panels capture less energy at higher latitudes?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Ekb9e.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ekb9e.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27611" LastActivityDate="2023-05-12T08:06:48.513" Title="Why do solar panels capture less energy at higher latitudes?" Tags="|sun|energy|insolation|" AnswerCount="1" CommentCount="4" ClosedDate="2023-05-31T08:13:56.760" ContentLicense="CC BY-SA 4.0" />
  <row Id="25184" PostTypeId="2" ParentId="25183" CreationDate="2023-05-12T08:06:48.513" Score="6" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;If that is indeed the case, then what is the real reason why solar panels capture less energy at higher latitudes?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;In a nutshell, &lt;a href=&quot;https://en.wikipedia.org/wiki/Air_mass_(solar_energy)&quot; rel=&quot;noreferrer&quot;&gt;air mass&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;You aren't going to get a nice suntan (or a not so nice sunburn) if you sit unprotected (no sunscreen, no hat, minimal clothing) in the Sun for ten minutes just before sunset. You might well get a nice suntan (or a not so nice sunburn) if you sit unprotected in the Sun for ten minutes at solar noon at the equator.&lt;/p&gt;&#xA;&lt;p&gt;The reason is that the radiation from the Sun has to pass through ever more atmosphere as the Sun's zenith angle increases. The zenith angle is 90° at sunrise and sunset, 0° when the Sun is directly overhead. The minimum zenith angle occurs at solar noon. At high latitudes, this is not all that low. The Sun is not directly overhead at high latitudes even at solar noon.&lt;/p&gt;&#xA;&lt;p&gt;Even without clouds, the Earth's atmosphere is not perfectly transparent. The atmosphere reflects/bends some of the incoming sunlight away from the Earth, and also absorbs some of that incoming sunlight. As I mentioned at the start of my answer, this concept is encapsulated by the somewhat &lt;em&gt;ad hoc&lt;/em&gt; principal of air mass. The amount of solar radiation that does reach the ground decreases with increasing solar zenith angle. Even at the northern hemisphere summer solstice, sunlight in Iceland is attenuated compared to sunlight in the tropics.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-05-12T08:06:48.513" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25185" PostTypeId="1" CreationDate="2023-05-12T13:05:10.627" Score="1" ViewCount="395" Body="&lt;p&gt;Can gold be found in the middle range of the Himalayas like in the Himachal Pradesh mountains or rivers above 3500 metres that come directly from the glaciers? Such as in the river banks of the Satluj river or mountains that are situated 3500 m above and rivers that comes directly from the glaciers in the upper Shimla and Kinnaur?&lt;/p&gt;&#xA;" OwnerUserId="28938" LastEditorUserId="2470" LastEditDate="2023-05-13T05:06:50.677" LastActivityDate="2023-05-16T20:52:58.180" Title="Can gold be found in middle range of the Himalayas like in Himachal Pradesh mountains or rivers above 3500 m that come directly from the glaciers?" Tags="|mountains|rivers|" AnswerCount="1" CommentCount="2" ClosedDate="2023-05-17T15:43:22.533" ContentLicense="CC BY-SA 4.0" />
  <row Id="25186" PostTypeId="1" CreationDate="2023-05-12T14:01:55.373" Score="1" ViewCount="81" Body="&lt;p&gt;In the sugarcane industry, we use Spent Wash (generated as waste in the distillation process) as fuel for stationary combustion. If we know that calorific value e.g 1650 kCal/kg for Spent Wash Briquette, is there any way to calculate the emission factor for this fuel?&lt;/p&gt;&#xA;" OwnerUserId="28939" LastEditorUserId="2470" LastEditDate="2023-05-13T05:08:37.513" LastActivityDate="2023-05-18T18:50:24.063" Title="How to calculate the emission factor for Spent Wash Briquette used as fuel in the sugarcane industry based on its calorific value?" Tags="|co2|fossil-fuel|emissions|climate-data|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25188" PostTypeId="1" AcceptedAnswerId="25195" CreationDate="2023-05-13T19:06:20.183" Score="1" ViewCount="59" Body="&lt;p&gt;I asked a question regarding mixing ratio and wet adiabatic lifting in&#xA;&lt;a href=&quot;https://stackoverflow.com/questions/76244447/why-is-mixing-ratio-at-lcl-not-the-same-as-for-starting-condition&quot;&gt;https://stackoverflow.com/questions/76244447/why-is-mixing-ratio-at-lcl-not-the-same-as-for-starting-condition&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I don't want to create a redundant copy of this question, but maybe the question can be answered here better than in the other community.&lt;/p&gt;&#xA;&lt;p&gt;Is it a problem in the python library or did I make a mistake in my reasoning?&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2023-05-13T19:13:03.023" LastActivityDate="2023-05-17T07:42:58.397" Title="Why is mixing ratio at LCL not the same as for starting condition?" Tags="|meteorology|atmosphere-modelling|python|metpy|condensation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25189" PostTypeId="2" ParentId="22728" CreationDate="2023-05-13T22:57:38.637" Score="0" Body="&lt;p&gt;There is no evidence of long term &lt;em&gt;change&lt;/em&gt; to the rate of flow (flux) of Earth's internal heat to the surface; without evidence of &lt;em&gt;variability&lt;/em&gt; it doesn't get treated as a &lt;em&gt;variable&lt;/em&gt;. It doesn't get included in climate models because there is no evidence it is a climate forcing over the time scales for anthropogenic global warming, not because it has been overlooked.&lt;/p&gt;&#xA;&lt;p&gt;Scientists have given consideration to every conceivable cause for climate to change, both in long term paleoclimate terms and specific to current observed warming. That includes use of temperature data from boreholes - which show warming (change) currently occurring from the surface down, diminishing as depth increases.&lt;/p&gt;&#xA;&lt;p&gt;Climate scientists have looked at estimates and quantification of heat fluxes and evidence of underlying change, found them to be inconsequential to observed and predicted climate change.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2023-05-13T22:57:38.637" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25190" PostTypeId="2" ParentId="16352" CreationDate="2023-05-14T09:59:05.993" Score="1" Body="&lt;p&gt;There is a measurable decay of airglow radiance during the night. Here's an example measurement of &lt;span class=&quot;math-container&quot;&gt;$\mathrm{OH}^-$&lt;/span&gt; infrared emissions (&lt;span class=&quot;math-container&quot;&gt;$\sim2\,\mathrm{\mu m}$&lt;/span&gt; wavelength) done on Mauna Kea in ref. 1:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kjuXh.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kjuXh.png&quot; alt=&quot;&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;h3&gt;References&lt;/h3&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;S. K. Ramsay, C. M. Mountain, T. R. Geballe, Non-thermal emission in the atmosphere above Mauna Kea, &lt;em&gt;Monthly Notices of the Royal Astronomical Society&lt;/em&gt;, Volume 259, Issue 4, December 1992, Pages 751–760, &lt;a href=&quot;https://doi.org/10.1093/mnras/259.4.751&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1093/mnras/259.4.751&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="12360" LastActivityDate="2023-05-14T09:59:05.993" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25193" PostTypeId="1" CreationDate="2023-05-16T18:53:09.187" Score="2" ViewCount="24" Body="&lt;p&gt;Fellow sedimentologists and geoscientists! I'm seeking your expertise in understanding a particular facies and its implications in terms of sedimentary processes and potential depositional environments. I have come across a facies in my research (see the attached picture), and I would greatly appreciate your insights and interpretations.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/vjNlr.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vjNlr.jpg&quot; alt=&quot;Image&quot; /&gt;&lt;/a&gt;&#xA;The facies in question exhibits distinct characteristics, such as (clast supported conglomerate but it seems to have a bedding!). Based on these observations, I am intrigued to unravel the underlying processes that contributed to the formation of this facies and to gain insights into the potential depositional environments it represents.&lt;/p&gt;&#xA;&lt;p&gt;Specifically, I would like to understand:&lt;/p&gt;&#xA;&lt;p&gt;Sedimentary Processes: What are the dominant sedimentary processes responsible for the deposition and formation of this facies? Are there any secondary processes that might have influenced its characteristics? Examples could include fluvial, aeolian, deltaic, glacial, or lacustrine processes, among others.&lt;/p&gt;&#xA;&lt;p&gt;Depositional Environments: Considering the identified features and sediment composition, what are the possible depositional environments that could have given rise to this facies? Are there any diagnostic indicators that suggest a specific environment, such as fluvial channels, tidal flats, dune fields, or deep-sea settings?&lt;/p&gt;&#xA;" OwnerUserId="28948" LastEditorUserId="28948" LastEditDate="2023-05-16T20:48:14.320" LastActivityDate="2023-05-16T20:48:14.320" Title="Understanding the Facies and its Interpretation in Terms of Processes and Possible Depositional Environments" Tags="|geology|sedimentology|petrography|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25194" PostTypeId="2" ParentId="25185" CreationDate="2023-05-16T20:52:58.180" Score="3" Body="&lt;p&gt;Gold can be found in various geological settings, including mountainous regions such as the Himalayas. In the middle range of the Himalayas, particularly in areas like Himachal Pradesh, there is potential for gold occurrences. While I don't have access to real-time data, it is known that gold has been found in some parts of Himachal Pradesh and the surrounding regions.&lt;/p&gt;&#xA;&lt;p&gt;Glacial rivers originating from the Himalayan glaciers can carry eroded material, including gold particles, downstream. The gold deposits in these rivers often form as a result of weathering and erosion of gold-bearing rocks and mineral veins upstream.&lt;/p&gt;&#xA;&lt;p&gt;Areas such as the river banks of the Satluj river and mountains situated above 3500 meters in upper Shimla and Kinnaur have the potential to contain gold deposits. These regions have a history of gold mining and exploration activities due to the presence of favorable geological conditions.&lt;/p&gt;&#xA;&lt;p&gt;It's worth noting that gold deposits are typically found in specific geological formations and structures, such as quartz veins or placer deposits. The presence and abundance of gold can vary significantly within a region, and detailed geological surveys, prospecting, and exploration activities are required to assess the potential for economic gold deposits in specific locations.&lt;/p&gt;&#xA;" OwnerUserId="28948" LastActivityDate="2023-05-16T20:52:58.180" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25195" PostTypeId="2" ParentId="25188" CreationDate="2023-05-17T07:42:58.397" Score="1" Body="&lt;p&gt;Has been answered in the other community: The discrepany is due to a different definition of relative humidity as used in the metpy function &lt;code&gt;mixing_ratio_from_relative_humidity&lt;/code&gt;.&lt;/p&gt;&#xA;&lt;p&gt;See also: &lt;a href=&quot;https://github.com/Unidata/MetPy/issues/2951&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://github.com/Unidata/MetPy/issues/2951&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21047" LastActivityDate="2023-05-17T07:42:58.397" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25196" PostTypeId="2" ParentId="25177" CreationDate="2023-05-18T18:43:07.797" Score="2" Body="&lt;p&gt;An example of an area with a high suspended sediment yield could be a steep mountainous region with a combination of specific properties. Let's consider the following characteristics:&lt;/p&gt;&#xA;&lt;p&gt;Steep Slopes: High suspended sediment yield is often associated with areas having steep slopes. Steep slopes increase the erosive power of flowing water, leading to a higher likelihood of sediment detachment and transport.&lt;/p&gt;&#xA;&lt;p&gt;Unconsolidated or Loose Soil: The area should have soil that is easily erodible, such as loose or unconsolidated sediment, which can be readily transported by flowing water. This can occur in regions with extensive weathering or areas with recent geological activity, such as landslides or glacial retreat.&lt;/p&gt;&#xA;&lt;p&gt;Sparse Vegetation Cover: In an area with limited vegetation cover, the soil is exposed and vulnerable to erosion by rainfall or runoff. Vegetation plays a crucial role in stabilizing soil and reducing erosion by intercepting rainfall, dissipating energy, and binding soil particles together with their roots.&lt;/p&gt;&#xA;&lt;p&gt;High Rainfall Intensity: Intense or heavy rainfall events can contribute to increased suspended sediment yield. High rainfall intensity leads to greater surface runoff, which can carry more sediment from the landscape into rivers or streams.&lt;/p&gt;&#xA;" OwnerUserId="28948" LastActivityDate="2023-05-18T18:43:07.797" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25197" PostTypeId="2" ParentId="25186" CreationDate="2023-05-18T18:50:24.063" Score="1" Body="&lt;p&gt;To calculate the emission factor for Spent Wash Briquette used as fuel in the sugarcane industry based on its calorific value, you need to follow these steps:&lt;/p&gt;&#xA;&lt;p&gt;Determine the calorific value: The first step is to determine the calorific value of the Spent Wash Briquette. Calorific value refers to the amount of heat energy released per unit mass of the fuel when it is burned. The calorific value is typically expressed in units like kilojoules per kilogram (kJ/kg) or megajoules per kilogram (MJ/kg).&lt;/p&gt;&#xA;&lt;p&gt;Collect emission data: Collect emission data specific to the combustion of Spent Wash Briquette. Emission data typically includes pollutants like carbon dioxide (CO2), carbon monoxide (CO), nitrogen oxides (NOx), sulfur dioxide (SO2), particulate matter (PM), and any other relevant emissions.&lt;/p&gt;&#xA;&lt;p&gt;Determine the emission factor: The emission factor represents the amount of emissions generated per unit of fuel consumed. It is typically expressed as emissions per unit mass or emissions per unit of energy produced. To calculate the emission factor, you need to divide the emissions associated with the combustion of Spent Wash Briquette by the amount of fuel consumed, usually expressed in mass or energy units.&lt;/p&gt;&#xA;&lt;p&gt;The specific calculation may vary depending on the emission data available and the units used. Here's a general formula for calculating the emission factor based on calorific value:&lt;/p&gt;&#xA;&lt;p&gt;Emission Factor = Emissions / Calorific Value&lt;/p&gt;&#xA;&lt;p&gt;Remember to ensure that the units of emissions and calorific value are consistent to obtain accurate results.&#xA;Lora&lt;/p&gt;&#xA;" OwnerUserId="28948" LastActivityDate="2023-05-18T18:50:24.063" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25198" PostTypeId="1" CreationDate="2023-05-18T19:24:30.230" Score="4" ViewCount="42" Body="&lt;p&gt;After the glaciations of the Cryogenian, Earth underwent a period of intense biodiversification which ultimately saw the emergence of the first animals of the succeeding Edicaran. What was it about the Cryogenian, or the alleviation of the icy conditions at the end of that period, that led to such evolution?&lt;/p&gt;&#xA;" OwnerUserId="27711" LastActivityDate="2023-05-18T19:24:30.230" Title="Cryogenian Earth and biodiversity" Tags="|paleoclimatology|evolution|precambrian|astrobiology|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25200" PostTypeId="1" CreationDate="2023-05-19T15:51:59.550" Score="1" ViewCount="40" Body="&lt;p&gt;When was the average thickness of the Earth's crust first calculated or estimated? What did scientists know about the thickness of the Earth's crust before the 20th century? In what interval(s) fell their measurements?&lt;/p&gt;&#xA;" OwnerUserId="28964" LastActivityDate="2023-05-19T15:51:59.550" Title="When was the thickness of the Earth's crust calculated?" Tags="|geology|sedimentology|crust|geologic-layers|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25201" PostTypeId="1" CreationDate="2023-05-19T17:26:08.780" Score="6" ViewCount="2776" Body="&lt;p&gt;We are taught that gravity is the force that keeps the atmosphere and everything else binded to Earth. However, observable reality shows us that the atmosphere expands in all directions as it fills any and all available volume. This is an observable natural phenomenon that can be observed from any place in the atmosphere at any time, from ground level up to the upper atmosphere.&#xA;I find a contradiction between this observation and my understanding of gravity especially because the atmosphere rises and expands in all directions right at the surface of Earth where the force of gravity is claimed to be it's strongest being that it's closest to the center of Earth's mass and just as important, it's still expanding in all directions at the highest altitudes. So if gravity can't hold it down at the surface of Earth how could it ever hold it down at any higher altitude.&lt;/p&gt;&#xA;" OwnerUserId="28965" LastActivityDate="2023-05-22T22:38:37.880" Title="How is the atmosphere expanding in all directions if Gravity is holding the atmosphere down to earth?" Tags="|gravity|" AnswerCount="8" CommentCount="12" ContentLicense="CC BY-SA 4.0" />
  <row Id="25202" PostTypeId="1" CreationDate="2023-05-19T18:28:53.380" Score="1" ViewCount="32" Body="&lt;p&gt;Is there any equation I can use to determine curve number as a function of the antecedent precipitation? I am aware of three sets of curve numbers for dry, wet and normal conditions. I was looking at a numerical expression, where I can adjust the curve number based on current moisture conditions (expressed using antecedent precipitation as a proxy).&lt;/p&gt;&#xA;&lt;p&gt;Adding some background on Curve Number:&lt;/p&gt;&#xA;&lt;p&gt;Curve number is an empirical parameter used for determining the runoff. It depends upon the soil group, land cover and any treatment applied to the soil.&lt;/p&gt;&#xA;&lt;p&gt;Here is the wikipedia article on Curve Number:&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Runoff_curve_number&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Runoff_curve_number&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27834" LastEditorUserId="27834" LastEditDate="2023-05-25T20:31:40.223" LastActivityDate="2023-05-25T20:31:40.223" Title="Curve number adjustment based on antecedent rainfall" Tags="|climate-change|climate|hydrology|urban-climate|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25203" PostTypeId="1" AcceptedAnswerId="25207" CreationDate="2023-05-19T20:01:49.080" Score="3" ViewCount="95" Body="&lt;p&gt;A geostrophic current in the northern hemisphere features a pressure gradient force directed towards the left of the current (west if the current heads straight north) and Coriolis force directed to the right. For the pressure gradient to be maintained, I can only conclude that the water on the right side of this current must be denser but instead looking at actual data (for example currents between Catalonia and Balearic Islands) it seems to be the opposite. Is my reasoning correct here or are there other circumstances that affect density distribution along currents?&lt;/p&gt;&#xA;" OwnerUserId="28351" LastActivityDate="2023-05-20T12:24:58.420" Title="Density of sea water on the side of currents" Tags="|oceanography|ocean-currents|mediterranean|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25204" PostTypeId="2" ParentId="25201" CreationDate="2023-05-19T22:19:39.043" Score="7" Body="&lt;p&gt;The Earth's atmosphere is held in place because it is more or less in hydrostatic equilibrium, where the pressure that would buoy it upward were it not for gravitation is in balance with the Earth's gravitation force that would otherwise pull the atmosphere downward.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-05-19T22:19:39.043" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25205" PostTypeId="2" ParentId="25201" CreationDate="2023-05-20T00:44:31.723" Score="5" Body="&lt;p&gt;In the radial direction (upwards), the atmosphere is very close to hydrostatic balance, and allows only very small fluctuations in velocity (Mach number &amp;lt;0.1%).&lt;br /&gt;&#xA;In the horizontal direction the atmosphere has much larger freedom of movement, being mainly constrained by the Coriolis and centrifugal balance at large scales, which can lead to wind speeds of up to 5-10% Mach number. Still small against a Mach number of 1, at which the atmosphere would depart from any pressure balance.&lt;/p&gt;&#xA;&lt;p&gt;This subsonic movement of gas is just shifting mass around, there is no net expansion of the atmosphere into space, which could only happen via a radial supersonic, or close-to-sonic expansion (a so-called planetary wind).&#xA;Hence the common saying (in scientific circles) that all movement in the atmosphere is just a small perturbation on top of a larger balance.&lt;/p&gt;&#xA;" OwnerUserId="489" LastEditorUserId="489" LastEditDate="2023-05-20T12:22:46.877" LastActivityDate="2023-05-20T12:22:46.877" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25206" PostTypeId="2" ParentId="25201" CreationDate="2023-05-20T03:39:14.343" Score="13" Body="&lt;p&gt;A couple thought experiments up front:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;If you breathe on a cold day, the air doesn't rush up, despite the&#xA;vacuum of space above it.  Why?  It's not just because of its own gravity... but because of the gravity (weight) of all the gas above it that tends to keep it suppressed overall.  Yes it does seem to spread in all directions diffusing, as gases do when there is room.  But there is more to come on that...&lt;/li&gt;&#xA;&lt;li&gt;But other gases show the situation more; if you put out dry ice (&lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt;), the gas will sink.  This is because it's heavier.  Despite being a gas and attempting to fill the free space.  And so gravity is pulling it (and other gases).  And that points out some of the way the atmosphere works.  The lower atmosphere actually works out to be a relatively free place where gases are mixed around more because of more energy.  But as you go up higher, the gases start to stratify out.  This is where gases with more mass per volume (= density) start to be held lower consistently.  So each tends to start to form a level.  (We're talking way up there, well above the height of commercial jets).  At highest levels, you find the lightest things like helium and hydrogen.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; motion is evidence that gravity is impacting gases.  But when you breathe out air, it is similar to the mixed gas around it and will be more free within it.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;There is another way to make gas &amp;quot;lighter&amp;quot; rather than changing what it's made out of... temperature.  Hot air balloons are an example of something that very much does go up specifically rather than just spread.  That's due to density (again, basically how heavy it is in a given volume, so very much a result of gravity).  Molecules move faster in warm air, so it's more spread out, so less weight per space, and so is lighter than the air around it and rises.  (Also why you may notice your breath indeed tending upwards on a cold day, and likewise from fires/industrial smokestacks, because they are warmer than the environment)&#xA;Yet air is less dense as you go up, so it still reaches levels where it stops rising. So what's left is colder and still less dense.  So there's a real significant decrease in gas as you go up, and air becomes much less dense (basically meaning gases will tend to stay below it, because it weighs more than the gas above it)&#xA;The majority of air winds up being at low levels because it is weighed upon by the air above it.  even in the &amp;quot;well-mixed&amp;quot; low atmosphere (go up in an airplane or up a mountain, your ears pop).  Higher up, more spread out means less total gas.&lt;br /&gt;&#xA;(Also worth noting is that the rising air expands to fill the increased space as it rises, but as it expands it uses up energy, cooling... and so stops rising)&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;So then doesn't the lightest gas, the gas at the top of the atmosphere, just leave?&lt;/p&gt;&#xA;&lt;p&gt;The answer still tends to be no... because it still has some weight.  (There's little remaining pressure force pushing it towards space because those top of atmosphere gases have reached very sparse quantities (= very low pressure)).  Everything at every level has an escape velocity... basically the amount of energy needed to overcome the (remaining) gravitational pull and reach space before it slows down too much from gravity.  &lt;a href=&quot;https://sci.esa.int/documents/33745/35957/1567258799920-Weihai-093-Coates-escape.pdf&quot; rel=&quot;noreferrer&quot;&gt;This powerpoint presentation&lt;/a&gt; shows that for our most common gases, molecules very rarely reach that speed.  For hydrogen and helium, the value is reached a bit more often, but still a very low percentage of the molecules, meaning it takes a long time.  But yes, the lightest gases do manage to escape, and in a way it is because they are meandering out to fill the space, more unrestrained by gravity than the heavier molecules that predominantly make up air.&lt;/p&gt;&#xA;&lt;p&gt;Some other important notes for your question:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The force of gravity is for most intents about the same at all levels of the atmosphere, because the atmosphere is so small compared to the Earth.  &lt;a href=&quot;https://www.quora.com/How-strong-is-gravity-at-the-edge-of-the-atmosphere&quot; rel=&quot;noreferrer&quot;&gt;This Quora question&lt;/a&gt; shows basically a 4% difference in gravity between the surface and top of atmosphere, and 9% to the ISS.  So there's really not much difference in gravity down low vs up high.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;So light gases and energetic molecules do escape.  Heavier gases sink, lighter ones rise.  So why isn't there a ton of insane motion?  Because over time the Earth reaches equilibrium in its distribution of the atmosphere... where the gases trended to move around until a point where the buoyancy (push up by gas molecules from below) and pressure gradient towards space were balanced by the weight at each level... the hydrostatic equilibrium the other answers mention. Less gas settles up high, more gas settles down low, until the forces balance.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;When you release a gas, you may well tend to be releasing a gas that was previously there.  So in a sense, it's expanding to fill the space that it once previously took up.  Of course you're taking out and putting back very tiny fractions of gas.  But you can imagine that if you did release a significant amount of &amp;quot;new&amp;quot; gas (from extraterrestrial sources, or from chemical reactions of substances previously tied up in other states of matter), you would add more gas, and it would overall tend to be growing the amount of gas taking up space, and would cause the atmosphere to change size.  And that would cause more gas to start to escape to space, by having a taller atmosphere.  (Likewise if you heated the Earth significantly)&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;But coming back to your questions:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;I find a contradiction between this observation and my understanding&#xA;of gravity especially because the atmosphere rises and expands in all&#xA;directions right at the surface of Earth where the force of gravity is&#xA;claimed to be it's strongest being that it's closest to the center of&#xA;Earth's mass and just as important, it's still expanding in all&#xA;directions at the highest altitudes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It may appear it is expanding in all directions.  But it is actually quite limited over time.  Perhaps a bit like how when you stir up sediments in water, it seems to be moving in all directions... but over time it will tend to be affected by gravity and sink back down.  And the majority of the gas will over time tend back towards the lower levels of the atmosphere because of gravity too.  And if you released air atmosphere at the higher altitudes (at matching temperature) of the thermosphere where it is &amp;quot;settled apart&amp;quot; more, it would tend to sink more notably (like CO2 does in our low-level atmosphere), more vividly showing how gravity is counteracting gases leaving.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2023-05-20T23:00:55.370" LastActivityDate="2023-05-20T23:00:55.370" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25207" PostTypeId="2" ParentId="25203" CreationDate="2023-05-20T12:19:29.863" Score="3" Body="&lt;p&gt;I believe it makes sense to factor in sea level height. If we assume a northward flow in geostrophic balance (see &lt;a href=&quot;https://en.wikipedia.org/wiki/Geostrophic_wind&quot; rel=&quot;nofollow noreferrer&quot;&gt;geostrophic wind&lt;/a&gt;) we have&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;fv = \frac{1}{\rho}\frac{\partial p}{\partial x}.&#xA;\end{equation}&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Using the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydrostatic_equilibrium&quot; rel=&quot;nofollow noreferrer&quot;&gt;hydrostatic relation&lt;/a&gt; we can replace the term on the right hand side and find&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;fv = g\frac{\partial h}{\partial x},&#xA;\end{equation}&lt;/span&gt;&#xA;(I assumed constant density &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt;) or equivalently&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\frac{\partial h}{\partial x} = \frac{fv}{g}.&#xA;\end{equation}&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;We can conclude that in order to maintain the geostrophic balance the sea level must rise the further we move east.&lt;/p&gt;&#xA;" OwnerUserId="18833" LastEditorUserId="18833" LastEditDate="2023-05-20T12:24:58.420" LastActivityDate="2023-05-20T12:24:58.420" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25208" PostTypeId="2" ParentId="25201" CreationDate="2023-05-20T16:18:54.480" Score="7" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;However, observable reality shows us that the atmosphere expands in all directions as it fills any and all available volume&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;A very close measurement will reveal that in the presence of gravity the gas does not fill the volume uniformly. The density will be slightly higher at the bottom than at the top. It is just that in everyday situations the difference is not readily observed.&lt;/p&gt;&#xA;&lt;p&gt;However, over the entire depth of the atmosphere the density varies from what we observe at the earth's surface and approaches zero as we rise arbitrarily high. But it never actually reaches zero no matter how far you rise (though one will reach an altitude where other effects like the solar wind will overwhelm any measurable atmosphere).&lt;/p&gt;&#xA;&lt;p&gt;So although the atmosphere is bound to the planet it occupies all of outer space; there is no true &amp;quot;top&amp;quot; to the atmosphere. For our own purposes we do define various boundaries between the atmosphere and out space, but these definitions are arbitrary.&lt;/p&gt;&#xA;&lt;p&gt;Indeed the density never actually reaches zero, and the effect of this is that the atmosphere of any planet will very slowly leak away.&lt;/p&gt;&#xA;" OwnerUserId="28968" LastActivityDate="2023-05-20T16:18:54.480" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25210" PostTypeId="1" AcceptedAnswerId="25216" CreationDate="2023-05-21T02:04:59.517" Score="2" ViewCount="90" Body="&lt;p&gt;ref : &lt;a href=&quot;https://science.ubc.ca/news/asteroid-impact-erosion-helped-make-earth-habitable&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://science.ubc.ca/news/asteroid-impact-erosion-helped-make-earth-habitable&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;According to the theory of impact erosion, the early crust was presumably much hotter w/ radioactive isotopes (U &amp;amp; K, primarily) and thus less congenial for the later development of life.  Asteroid bombardment - I suppose during the late heavy bombardment - then blew off a sufficient chunk of this material to lower net radioactivity in the crust.&lt;/p&gt;&#xA;&lt;p&gt;Was this simply because beforehand for some reason there was an upward gradient of radioactivity in the primeval crust ?  I'm at a loss to conceive a selective mechanism for this phenomenon.  Any paleo-geologists in the house ?&lt;/p&gt;&#xA;" OwnerUserId="14361" LastEditorUserId="14361" LastEditDate="2023-05-24T07:36:44.740" LastActivityDate="2023-05-24T07:36:44.740" Title="Impact Erosion Selectivity In Offloading Radioactive Material" Tags="|geophysics|earth-history|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="25211" PostTypeId="2" ParentId="25201" CreationDate="2023-05-21T03:04:34.087" Score="4" Body="&lt;p&gt;The simple answer is that it does not rise and expand in all directions. In your house or outside, the air is generally not expanding or contracting, and, on balance, neither rising nor sinking. Consider what happens when you blow up a balloon. If the air inside it was constantly expanding, then the balloon would get bigger even after you sealed it until it popped.&lt;/p&gt;&#xA;&lt;p&gt;Of course, there are updrafts and downdrafts. But they balance out.&lt;/p&gt;&#xA;&lt;p&gt;Certainly, if you pump all the air out of a chamber, and then open a valve to let air back in, it will expand in the chamber until it fills all the available space. But that is precisely because gravity is pulling down on the air everywhere, and the empty chamber is a place for the air to go to &amp;quot;get out of the way&amp;quot; of the surrounding air that's being pressed down by the weight of the air above it.&lt;/p&gt;&#xA;&lt;p&gt;You say, &amp;quot;observable reality shows us that the atmosphere expands in all directions as it fills any and all available volume.&amp;quot; But most available volume has already been filled, and once that happens, it stops expanding. It doesn't all just expand out into space and disappear.&lt;/p&gt;&#xA;" OwnerUserId="22292" LastActivityDate="2023-05-21T03:04:34.087" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25212" PostTypeId="2" ParentId="25201" CreationDate="2023-05-21T03:37:49.707" Score="4" Body="&lt;p&gt;Air at the same temperature and density released into (still) air at the same pressure will result in &lt;a href=&quot;https://en.wikipedia.org/wiki/Diffusion&quot; rel=&quot;nofollow noreferrer&quot;&gt;diffusion&lt;/a&gt;; it is an &lt;em&gt;exchange&lt;/em&gt; of molecules where the individual molecules rarely go far in one go before bouncing off other molecules. Diffusion is a consequence of the energetic motions of molecules and their statistical randomness - there is no preferred direction. The mixture will tend to homogenize and tracking the individual molecules will show an expansion until homogeneity is reached - or other factor intevene. Atmosphere is not still and wind and turbulence mix and disperse them over longer distances.&lt;/p&gt;&#xA;&lt;p&gt;Air released into vacuum will expand in all directions, because of air pressure, which is a consequence of those energetic motions of molecules and collisions with other molecules - which, embodying energy that is conserved, do not subside over time - but each molecule is also affected by gravity, so air released into a vacuum chamber on Earth is not expanding equally in all directions. The pressure gradient - from having the mass of air above plus gravity - will exist, even if very small elevation differences of a chamber would mean extremely precise measurements would be needed to detect it.&lt;/p&gt;&#xA;&lt;p&gt;To escape to space a gas molecule needs a free path (no other molecules in the way) and sufficient velocity but on average gas molecules travel more slowly than Earth's escape velocity and relatively few manage to escape to space.&lt;/p&gt;&#xA;&lt;p&gt;Where there is a free path (above most of the atmosphere) it is also colder, with slower average velocity.&lt;/p&gt;&#xA;&lt;p&gt;To settle on the ground the energetic motions of gas molecules that prevent their compression  has to slow a lot, ie it has to shed energy and cool, to liquid and ultimately solid.&lt;/p&gt;&#xA;&lt;p&gt;The molecules on average aren't fast enough (ie hot enough) to reach space and too fast (not cold enough) to settle to the ground. It is held between, in equilibrium.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2023-05-21T03:37:49.707" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25216" PostTypeId="2" ParentId="25210" CreationDate="2023-05-22T08:54:05.873" Score="2" Body="&lt;p&gt;All the &lt;a href=&quot;https://doi.org/10.1038/ngeo2488&quot; rel=&quot;nofollow noreferrer&quot;&gt;original research paper&lt;/a&gt; is saying is that there might be less radioactive elements in the silicate Earth (crust + mantle) than previously thought. And if there had been more of those elements, there would have been more internal heat, thus a different tectonic regime, a different volcanism, a different geodynamo, a different atmosphere... And maybe, maybe, these different conditions would have prevented the emergence of life.&lt;/p&gt;&#xA;&lt;p&gt;Also, don't forget that even is uranium is dense, it doesn't &amp;quot;sink below the crust&amp;quot;. The mantle is solid rock, uranium is trapped in the crystal lattice of minerals, but it is an incompatible element, meaning it will preferentially go into the melt when the mantle partially melt. These melts then rise by buoyancy and actually make the bulk of the continental crust. So it makes perfect sense that the crust is uranium-enriched and the mantle uranium-depleted. Then, if you remove some of this crust after its formation, you will indeed remove some radioactive elements compared to the original composition (I'm not saying it happened, but the model is perfectly logical).&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2023-05-22T08:54:05.873" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25217" PostTypeId="2" ParentId="25201" CreationDate="2023-05-22T12:03:19.833" Score="2" Body="&lt;p&gt;&lt;strong&gt;The effect of gravity on gas molecules is too small to notice on small laboratory scales&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;What you observe in a small laboratory scale is not representative of what you observe on a large scale. But there are other observations that hint the small scale experiments in a lab where a gas released &amp;quot;fills the space&amp;quot; dont tell us everything. For example, the atmospheric pressure at the top of everest is less than 1/3 the value at sea level. So, on a large scale, gases clearly don't &amp;quot;fill the space&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;But why the disparity between the two experiments? Consider a single gas molecule in air. To vastly simplify, it moves with an average speed of about 500 m/s. If it were an isolated ball moving directly upwards, it would, under gravitational acceleration, stop moving at something like 30km up.&lt;/p&gt;&#xA;&lt;p&gt;But there are plenty of other factors influencing its motion in the laboratory atmosphere. The mean free path of a typical air molecule (nitrogen or oxygen) in lab conditions is &amp;lt;100 nm. So the possibility of measuring the impact of gravitation on its motion, even under purely diffusion controlled conditions, is pretty, impossibly low. And this ignores turbulence (ie weather) which thoroughly mixes the lower atmosphere making it even harder to see any gravitational effects (which would, for example, lead to denser molecules being more common lower in the atmosphere). In fact the separation by component is unobservable at the top of Everest for this reason. The equilibrium effect balancing the kinetic energy with the effect of gravity on particle motion manifests as lower pressure with higher altitude.&lt;/p&gt;&#xA;&lt;p&gt;So for reasons of simple physics, gravity &lt;em&gt;does&lt;/em&gt; have an effect but such a small one that it only becomes apparent over scales of kilometers. If you had a vacuum in a tube a kilometer or two tall and released gas into it, you would observe a lower pressure at the top compared to the bottom. The gas would &lt;em&gt;not&lt;/em&gt; expand evenly to fill the tube. Most labs are not that tall so the effect is not observable on the lab scale. But can be seen easily if you travel up a tall building or a modest mountain while holding a barometer.&lt;/p&gt;&#xA;" OwnerUserId="3333" LastEditorUserId="3333" LastEditDate="2023-05-22T22:38:37.880" LastActivityDate="2023-05-22T22:38:37.880" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25218" PostTypeId="2" ParentId="25201" CreationDate="2023-05-22T14:34:18.317" Score="1" Body="&lt;p&gt;Let's look at a cube of air in the atmosphere—say a 1 m × 1 m × 1 m large cube.&lt;/p&gt;&#xA;&lt;p&gt;While the force on that cube caused by the gravity of the Earth is directed downwards and pulls that cube towards Earth, there is another force that counters that force and pushed the cube away from Earth. This counteracting force is caused by the fact that the pressure in the air just below the cube if higher than the pressure of the air just above the cube, since the pressure steadily decreases the higher up in the atmosphere you get.&lt;/p&gt;&#xA;&lt;p&gt;The pressure of the air just below the cube, when multiplied by the area of the side of the cube that is directed downwards (which is 1 m × 1 m or 1 m²), causes an upwards force on that cube that effectively pushes the cube away from Earth.&lt;/p&gt;&#xA;&lt;p&gt;Now, this force is much greater than the force caused by the gravity, but there is also a corresponding downwards force caused by the pressure of the air just above the cube, which effectively pushes the cube downwards, which is almost as great as the upwards force from the pressure of the air just below the cube. And it so happens that the sum of the force cause by the pressure of the air just above the cube, and the force caused by the gravity, equals to the force caused by the pressure in the air just below the cube. So, the net force on the cube is zero, and that's why the air doesn't just fall down to the surface of the Earth.&lt;/p&gt;&#xA;&lt;p&gt;I have ignored the forces on the cube caused by the pressure of the air on each of the four sides in the horizontal directions, since the pressure there is symmetric and thus those forces cancel each other out.&lt;/p&gt;&#xA;&lt;p&gt;Or, at least that's the case in the ideal scenario. In reality, you have pressure fluctuations which makes the net force deviate slightly from zero. This in turn cases an acceleration and consequently movement of the air, which we call &amp;quot;wind.&amp;quot;&lt;/p&gt;&#xA;" OwnerUserId="28065" LastActivityDate="2023-05-22T14:34:18.317" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25219" PostTypeId="1" CreationDate="2023-05-24T10:28:32.990" Score="1" ViewCount="24" Body="&lt;p&gt;I am thinking of the interaction of two different uncertainties; ecological regime shift uncertainty and natural resource variability.&lt;/p&gt;&#xA;&lt;p&gt;For example, for fishes, we know that the fish stock is exposed to an abrupt decrease in risk (regime shift). Also, there is always natural resource variability, which represents another source of uncertainty.&lt;/p&gt;&#xA;&lt;p&gt;Are there any scientific evidence that natural resource variability increases/decreases after the occurrence of a regime shift?&lt;/p&gt;&#xA;&lt;p&gt;I gave an example for fishes but it can be any sort of common pool resources.&lt;/p&gt;&#xA;" OwnerUserId="2827" LastActivityDate="2023-05-24T10:28:32.990" Title="Ecological regime shifts and natural resource variability" Tags="|resources|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25220" PostTypeId="2" ParentId="24479" CreationDate="2023-05-24T12:28:33.680" Score="3" Body="&lt;p&gt;Here is the answer from the Support Team of Copernicus:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The definition of the 0 m elevation for ocean areas is not dependent on the acquisition date of the input images. Please note that the Copernicus DEM is quality-based combination of multiple acquisitions which, from our understanding, prevents to focus on just a single scene and the ocean extent present at that day. Elevation 0m in the Copernicus DEM is more general and referring to the mean sea level of the vertical reference datum of this DEM (i.e., Earth Gravitational Model 2008 - EGM 2008).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="18828" LastActivityDate="2023-05-24T12:28:33.680" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25222" PostTypeId="1" AcceptedAnswerId="25224" CreationDate="2023-05-27T02:41:44.970" Score="1" ViewCount="121" Body="&lt;p&gt;I have lived nearly my entire life in the same home. It appears to me, the hottest part of the day is getting a bit latter in the day. I tired doing a google search, but I did not see any links that would support this idea. Also, I do not have any hard data to back up my claim.&lt;/p&gt;&#xA;&lt;p&gt;I am thinking there is more CO&lt;sub&gt;2&lt;/sub&gt; in the atmosphere now, so it takes more time for the sun to heat it up and therefore the hottest part of the day is latter.&lt;/p&gt;&#xA;&lt;p&gt;Here are some links that I have looked at:&#xA;&lt;a href=&quot;https://ownyourweather.com/hottest-and-coldest-time-of-the-day/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Own your weather&lt;/a&gt;&#xA;&lt;a href=&quot;https://airdensityonline.com/2017/02/hottest-a-couple-hours-after-noon/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Air Density&lt;/a&gt;&#xA;&lt;a href=&quot;https://nbc5weather.wordpress.com/2008/07/28/what-is-the-hottest-time-of-the-day/&quot; rel=&quot;nofollow noreferrer&quot;&gt;nbc5weather&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Am I right about any/all of this?&lt;/p&gt;&#xA;" OwnerUserId="28995" LastEditorUserId="2470" LastEditDate="2023-05-28T02:26:38.313" LastActivityDate="2023-05-28T02:26:38.313" Title="The hottest part of the day" Tags="|climate-change|climate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25223" PostTypeId="1" CreationDate="2023-05-27T07:54:35.940" Score="2" ViewCount="47" Body="&lt;p&gt;I tried reading Arrhenius' paper (&lt;a href=&quot;https://www.rsc.org/images/Arrhenius1896_tcm18-173546.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.rsc.org/images/Arrhenius1896_tcm18-173546.pdf&lt;/a&gt;), but having no background in natural sciences, it was too inaccessible to me. What is the high-level outline of the consecutive steps of his line of argumentation?&lt;/p&gt;&#xA;" OwnerUserId="28996" LastActivityDate="2023-05-27T07:54:35.940" Title="What arguments does Svante Arrhenius make in 1896 to prove the correlation between &quot;carbonic acid&quot; and ground temperature increase?" Tags="|climate-change|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25224" PostTypeId="2" ParentId="25222" CreationDate="2023-05-27T09:32:30.530" Score="3" Body="&lt;p&gt;It is not as simple as this, as the temperature is not related just with the CO2 or sun radiation but: some other gases, moisture, wind, cloud presence...&lt;/p&gt;&#xA;&lt;p&gt;One thing is the real dry temperature, that you can get from a weather station and another subject is &amp;quot;feels-like&amp;quot; temperature, that takes in account water pressure, wind... It is more close to what you can feel as temperature.&lt;/p&gt;&#xA;&lt;p&gt;For the real dry temperature, main actor is sun radiation, as soon as you get more radiation, you are increasing temperature as all the gases at the atmosphere become excited by radiation. As soon as you reduce radiation, temperature is becoming low.&lt;/p&gt;&#xA;&lt;p&gt;I recomend you to check by yourself. There are some more &amp;quot;free&amp;quot; webpages when you can get weather data as solar radiation and temperature and check how they are changing along the day. I used &lt;a href=&quot;https://www.visualcrossing.com/weather-data&quot; rel=&quot;nofollow noreferrer&quot;&gt;this link&lt;/a&gt; to get data from different places at different latittudes, as solar radiation, on the same days, varies in value and time.&lt;/p&gt;&#xA;&lt;p&gt;Case 1: Paris 2023-05-19 to 2023-05-26&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/M8gNC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/M8gNC.png&quot; alt=&quot;Paris 2023-05-19 to 2023-05-26&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;In this case, as soon as you are getting radiation, you are increasing temperature. Highest temperature has just 30 minutes delay from highest solar radiation. If you pay attention to feels-lie temperature, delay is different. That is why you feel that the hottest hours are a few hours after maximum radiation.&lt;/p&gt;&#xA;&lt;p&gt;Case 2: Singapore 2023-05-19 to 2023-05-26&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/V6m73.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/V6m73.png&quot; alt=&quot;Singapore 2023-05-19 to 2023-05-26&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;In this case, as it is an area that it is almost constantly cloudy with high humidity, temperature is varying just a little bit, and except the first day of the period, it seems that there is no relationship. In fact, on the second day there was a storm (I am living now at Singapore) and it is reflected in a quick change in temperature (both) and solar radiation.&lt;/p&gt;&#xA;&lt;p&gt;Conclusion: It is not as simple as it seems.&lt;/p&gt;&#xA;&lt;p&gt;Hope it helps!&lt;/p&gt;&#xA;" OwnerUserId="18035" LastActivityDate="2023-05-27T09:32:30.530" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25225" PostTypeId="2" ParentId="4928" CreationDate="2023-05-29T02:08:08.043" Score="1" Body="&lt;p&gt;This answer delves a bit more into the reaction mechanism, which involves two parts: the formation of metal hydroxide and the conversion of iron hydroxide to magnetite with the evolution of hydrogen. The key feature is that ferrous ions are really stable only in acidic or neutral conditions, whereas the reactions in serpentization inherently make the environment basic.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Hydroxide formation&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Serpentization occurs in mafic rock, which inherently produces basic products when decomposed by water. The calcium, magnesium and iron displaced from the rock emerge as hydroxides. Even where carbon dioxide is present and converts the calcium to relatively insoluble &lt;span class=&quot;math-container&quot;&gt;$\text{CaCO}_3$&lt;/span&gt;, magnesium hydroxide is more resistant to this process and thus appears as the mineral &lt;a href=&quot;https://en.wikipedia.org/wiki/Brucite&quot; rel=&quot;nofollow noreferrer&quot;&gt;brucite&lt;/a&gt;. This magnesium hydroxide is still a strong enough base to also favor the iron forming a hydroxide rather than remaining in solution as ions, setting the stage for ...&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;The Schikorr reaction&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Iron in mafic rocks is predominantly in the form of iron(II) and thus its hydroxide would be ferrous hydroxide, &lt;span class=&quot;math-container&quot;&gt;$\text{Fe(OH)}_2$&lt;/span&gt;. Unlike dissolved ferrous ions, this hydroxide can displace hydrogen from water via the &lt;a href=&quot;https://en.wikipedia.org/wiki/Schikorr_reaction&quot; rel=&quot;nofollow noreferrer&quot;&gt;Schikorr reaction&lt;/a&gt;, forming magnetite (&lt;span class=&quot;math-container&quot;&gt;$\text{Fe}_3\text{O}_4$&lt;/span&gt;) with evolution of hydrogen:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\text{3 Fe(OH)}_2 \to \text{Fe}_3\text{O}_4 + \text{H}_2 + 2\text{H}_2\text{O}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;This reaction is well known not only in serpentization but also as a component reaction in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Rust&quot; rel=&quot;nofollow noreferrer&quot;&gt;rusting of iron&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2023-05-29T10:54:37.983" LastActivityDate="2023-05-29T10:54:37.983" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25227" PostTypeId="1" CreationDate="2023-05-29T21:05:07.533" Score="2" ViewCount="2016" Body="&lt;p&gt;The paper, &lt;a href=&quot;https://arxiv.org/pdf/2006.03098.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Dependence of Earth’s Thermal Radiation on Five Most&#xA;Abundant Greenhouse Gases&lt;/em&gt;&lt;/a&gt;&lt;sup&gt;1&lt;/sup&gt;, has been reportedly rejected from several major journals.  By analysing absorption spectra of greenhouse gases in more detail than has been done previously, it claims to show that CO2 is now effectively saturated (with respect to radiative forcing) and any further increase in atmospheric concentrations will lead to negligible temperature change at the surface.  Their numerical results agree with previous literature on the subject.  The authors are known climate emergency sceptics.  While noting that it is obvious that if the result is correct there would be enormous political ramifications, my question is not concerned with those.&lt;/p&gt;&#xA;&lt;p&gt;Presuming the article is not being published because it's so incorrect it doesn't merit peer review, &lt;strong&gt;I would like to know &lt;em&gt;precisely and technically&lt;/em&gt; why the paper is wrong&lt;/strong&gt;.  The authors are physicists so I would like to understand its flaws from the perspective of climate science if possible.&lt;/p&gt;&#xA;&lt;p&gt;I am specifically &lt;em&gt;not&lt;/em&gt; interested in hearing arguments along the lines of &amp;quot;the IPCC is right and this is incompatible with that so it must be wrong&amp;quot; - again I am looking for a precise and technical rebuttal.&lt;/p&gt;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;[1] W. A. van Wijngaarden and W. Happer, &lt;a href=&quot;https://arxiv.org/pdf/2006.03098.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;“Dependence of Earth’s Thermal Radiation on Five Most Abundant Greenhouse Gases.”&lt;/a&gt; arXiv, 2020. doi: 10.48550/ARXIV.2006.03098.&lt;/p&gt;&#xA;" OwnerUserId="29004" LastActivityDate="2023-10-24T16:32:27.990" Title="What is technically wrong with Wijngaarden &amp; Happer's paper claiming to show that CO2's contribution to surface warming is saturated?" Tags="|climate-change|geophysics|climate-models|atmospheric-radiation|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25228" PostTypeId="2" ParentId="14029" CreationDate="2023-05-29T22:57:42.543" Score="0" Body="&lt;p&gt;In the case of carbon, much of that element may have been sunk into Earth's core. Carbon is much more soluble in iron, especially liquid iron, than other nonmetals in the Periodic Table (which are more likely to form compounds instead), so it is likely to concentrate in the core. From [Fischer et al. &lt;a href=&quot;https://doi.org/10.1073/pnas.1919930117&quot; rel=&quot;nofollow noreferrer&quot;&gt;1&lt;/a&gt;]:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Based on a multistage model of core formation, the core likely contains a maximum of 0.09(4) to 0.20(10) wt% C, making carbon a negligible contributor to the core’s composition and density. However, this accounts for ∼80 to 90% of Earth’s overall carbon inventory, which totals 370(150) to 740(370) ppm. The bulk Earth’s carbon/sulfur ratio is best explained by the delivery of most of Earth’s volatiles from carbonaceous chondrite-like precursors.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Rebecca A. Fischer, Elizabeth Cottrell , Erik Hauri, and Marion Le Voyer (2020). &amp;quot;Carbon content of Earth and its core&amp;quot;, &lt;em&gt;PNAS&lt;/em&gt; &lt;strong&gt;117&lt;/strong&gt; (16) 8743-8749. Edited by David Walker, Columbia University.&#xA;&lt;a href=&quot;https://doi.org/10.1073/pnas.1919930117&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1073/pnas.1919930117&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2023-05-29T22:57:42.543" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25229" PostTypeId="1" AcceptedAnswerId="25312" CreationDate="2023-05-29T20:32:45.127" Score="2" ViewCount="203" Body="&lt;p&gt;Here's a global map of magnetic declination:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/YLA6v.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YLA6v.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;How can there be zero magnetic declination in places where the magnetic and geographic poles don't line up (which is only at approx. latitude 0 and 180 for the northern hemisphere)? And why are the lines so crooked?&lt;/p&gt;&#xA;" OwnerUserId="29009" OwnerDisplayName="new editor" LastEditorUserId="29009" LastEditDate="2023-05-30T17:10:25.640" LastActivityDate="2023-07-12T11:47:16.943" Title="How can there be zero magnetic declination in places where the magnetic and geographic poles don't line up" Tags="|geomagnetism|" AnswerCount="3" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25230" PostTypeId="2" ParentId="25229" CreationDate="2023-05-29T20:57:14.913" Score="3" Body="&lt;p&gt;A pole is a point. If you have two points then there are places where they line up if you'd look towards them.&lt;/p&gt;&#xA;&lt;p&gt;For the geographic and magnetic poles we use &amp;quot;declination&amp;quot; to describe the angle between the direction towards geographic north versus the angle that the magnetic compass needle points to.&lt;/p&gt;&#xA;&lt;p&gt;If you are in a place where both line up, then the declination is 0°.&lt;/p&gt;&#xA;&lt;p&gt;Plotted on map those places form crooked lines because there is &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_magnetic_field#Geographical_variation&quot; rel=&quot;nofollow noreferrer&quot;&gt;geographic variation in Earth's magnetic field&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="29015" OwnerDisplayName="bugmenot123" LastActivityDate="2023-05-29T20:57:14.913" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25231" PostTypeId="1" CreationDate="2023-05-30T09:00:58.693" Score="5" ViewCount="408" Body="&lt;p&gt;I would like to know how can we determine if the river is wide. Is there any classification or consideration that can be done based on the width, depth, and length of the river?&lt;/p&gt;&#xA;" OwnerUserId="29007" LastEditorUserId="2470" LastEditDate="2023-05-30T09:46:57.563" LastActivityDate="2023-05-31T08:06:58.353" Title="Classification of river" Tags="|rivers|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25232" PostTypeId="2" ParentId="25231" CreationDate="2023-05-30T13:14:10.687" Score="10" Body="&lt;p&gt;It is not easy to classify rivers, especially on the basis that many rivers evolve (see fig) and that man often interferes with the river, but there is a good classification according to Dong-Geun Yoo, which gives different criteria for river classification. For example, the shape of the erosion valley, the width of the river branches, etc.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LRioU.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LRioU.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.researchgate.net/figure/River-classification-delineation-showing-longitudinal-cross-sectional-and-plan-views-of_fig3_315965422&quot; rel=&quot;noreferrer&quot;&gt;https://www.researchgate.net/figure/River-classification-delineation-showing-longitudinal-cross-sectional-and-plan-views-of_fig3_315965422&lt;/a&gt;  (also more details)&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2023-05-31T08:06:58.353" LastActivityDate="2023-05-31T08:06:58.353" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25233" PostTypeId="1" AcceptedAnswerId="25235" CreationDate="2023-05-30T19:53:45.360" Score="2" ViewCount="406" Body="&lt;p&gt;Greetings fellow scholars,&lt;/p&gt;&#xA;&lt;p&gt;I'm trying to answer the question above because I've come across WBGT calculators like this one (&lt;a href=&quot;https://www.climatechip.org/heat-stress-index-calculation&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.climatechip.org/heat-stress-index-calculation&lt;/a&gt;) and I don't understand how the answers are derived using the Liljegren method without more variables (other than temperature, humidity and assumptions on direct sunlight and wind speed).&lt;/p&gt;&#xA;&lt;p&gt;The paper, &lt;a href=&quot;https://doi.org/10.1080/15459620802310770&quot; rel=&quot;nofollow noreferrer&quot;&gt;Liljegren et al. (2008)&lt;/a&gt;, method is pay walled. I've tried digging into the code of projects like &lt;a href=&quot;https://rdrr.io/github/anacv/HeatStress/src/R/wbgt.Liljegren.R&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one&lt;/a&gt; but they're using more variables.&lt;/p&gt;&#xA;&lt;p&gt;If anyone can give an explanation of what's going on with these calculators or point me to a code repo/paper where I can try learn more, please do.&lt;/p&gt;&#xA;" OwnerUserId="28984" LastEditorUserId="18081" LastEditDate="2023-05-30T20:49:50.143" LastActivityDate="2023-05-31T08:26:17.777" Title="How to calculate wet bulb globe temperature (WBGT) using only temperature and humidity?" Tags="|temperature|measurements|humidity|data-analysis|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25234" PostTypeId="2" ParentId="4881" CreationDate="2023-05-31T06:23:35.457" Score="2" Body="&lt;p&gt;In fact, columnar jointing like this is common in nature and also appears in other rock types all around the world, especially in other lavas, subvolcanic intrusive (i.e. dikes, sills, laccoliths) igneous rocks, and welded tuffs/ignimbrites, but also in &lt;a href=&quot;http://www.b14643.de/Sahara/Sandstone-Columns/index.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;sandstones&lt;/a&gt; (in the case of sandstones, they are nearly always associated with heat transfer from nearby magmatic intrusions—&lt;strong&gt;note: please ignore the unscientific BS about “plasma” in the previous link—I linked it solely for the great photos of columnar sandstone, which are hard to come by&lt;/strong&gt;).&lt;/p&gt;&#xA;&lt;p&gt;In the case of columns in lavas and other igneous rocks, tensile stresses develop parallel to the cooling surface, and in the case of sandstones, they develop parallel to the heating surface.  In the case of lavas, these stresses develop as the lava or magma slowly and progressively cools from the outside-inwards, because solid, cooled rock is denser than liquid and hot rock. Stresses develop in columnar sandstones because sandstones are porous, which allows the passage and presence of water within them, and this water is heated by underlying igneous intrusions causing hydrothermal circulation and convection to occur.&lt;/p&gt;&#xA;&lt;p&gt;Many igneous intrusions and lava flows are tabular in shape, which results in regular, extensive colonnades, but many times you will also see columns that are oriented radially, for example, in a former volcanic conduit or neck, because the cooling surface was cylindrical, around the walls of the conduit, oriented horizontally, in the case of vertically emplaced dikes, or every-which-way, for example, when columns form in a lava flow that fills an irregularly-shaped valley, or in subglacial eruptions, where the lava has irregular ice-marginal contact.  The important point to realize here is that the tensile stress is always parallel to the thermally-contrastive surface, and so joints develop normal to that surface.&lt;/p&gt;&#xA;&lt;p&gt;These columnar joints begin forming from existing cracks on opposite surfaces of the rock layer.  As the cracks develop, and they &lt;a href=&quot;https://i.imgur.com/i0Z4j6s.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;develop&lt;/a&gt; sequentially, bit by bit—the size of that bit determined by scaling laws that relate to the spacing of the joints and the strength of the rock (ultimately this forms secondary lines called &lt;em&gt;striae&lt;/em&gt; across the columns, I won’t get into this, but check out the Phillips et al. and Goehring &amp;amp; Morris papers linked at the end for the detail)—and each time they crack, the direction of the crack changes slightly, guided by the &lt;a href=&quot;https://i.imgur.com/Pv2VSuy.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;tensile stress field&lt;/a&gt; that permeates the rock (again, from thermal energy).  At the beginning of the process, these joints are immature, and the degree of hexagonality is very low—the columns may start out irregular, of many shapes and sizes, with curved sides even.  But gradually, over a large region where these tensile stresses are acting equally on the rock (for example, a large sill or lava flow cooling at the same rate, or a tabular body of sandstone with uniform porosity over a sill), the joints develop and mature, tending towards the most energy-efficient configuration.  This same process occurs when corn starch dries, by the way—you can watch the maturation of columns actually occurring in this &lt;a href=&quot;https://youtu.be/nyz35cJwz2s&quot; rel=&quot;nofollow noreferrer&quot;&gt;video&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;This happens to coincide with a &lt;a href=&quot;https://i.imgur.com/0Uae1aI.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;geometric construction&lt;/a&gt; known as a &lt;em&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Voronoi_diagram#Examples&quot; rel=&quot;nofollow noreferrer&quot;&gt;Voronoi tessellation&lt;/a&gt;&lt;/em&gt;.  Essentially, the center of each column becomes the center of a Voronoi polygon, which is defined by sides which are equidistant from each surrounding other center of every other polygon.  And the most efficient distribution of Voronoi polygons is all hexagons, spaced equally from one another.  Therefore, if all other factors (permeation by precipitation, mineral changes, groundwater, irregular surfaces, internal cavities and fractures, etc) were able to be ignored, if a basalt flow could be allowed to mature infinitely, it would always tend towards perfect hexagonal columns.  Of course, in nature things are not perfect, and basalt flows don’t have infinite joint length to spare or infinite time to cool, so eventually the columns are left in whatever state of maturation they ended up in.  Typically that looks like mostly 6-sided columns, but with plenty of 5- and 7-sided columns, and a few 4- and 8-sided columns.  Watch a Voronoi tessellation mature in &lt;a href=&quot;https://youtu.be/NV_YXUModcQ&quot; rel=&quot;nofollow noreferrer&quot;&gt;this video&lt;/a&gt; (white-to-yellow-to-orange indicate hexagons—the whiter they are, the more regular in shape, while orange and blue indicate non-hexagons)&lt;/p&gt;&#xA;&lt;p&gt;As you can see in &lt;a href=&quot;https://i.imgur.com/cK4SBaK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;this image&lt;/a&gt;, which charts a Voronoi tessellation as it becomes more mature, the number of 6-sided polygons peaks, and the number of other sides decreases.&lt;/p&gt;&#xA;&lt;p&gt;Most columns are five- or six-sided, but some are also four-sided, seven-sided, and eight-sided. &lt;a href=&quot;https://i.imgur.com/UUpY02F.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; are some statistics of the number of sides of columns from outcrops all over the world. I highlighted the number of sides and also an index χₙ, &lt;em&gt;the index of hexagonality&lt;/em&gt;, a calculated measure of how hexagonal the columns in an outcrop are (see below for an explanation).&lt;/p&gt;&#xA;&lt;p&gt;—&lt;/p&gt;&#xA;&lt;p&gt;A note on the index of hexagonality, χₙ:&lt;/p&gt;&#xA;&lt;p&gt;χₙ gives the deviation of all columns in an outcrop from all being 6-sided.  It is calculated using the formula:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;χₙ = √(f₅ + f₇) + 4(f₄ + f₈) + 9(f₃ + f₉) + 16f₁₀ + 25f₁₁ + …&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;em&gt;where fₙ is the fraction of columns in the outcrop with n sides&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;So basically, you add up the fraction of columns with 5 and 7 sides, plus 4 times the fraction of columns with 4 and 8 sides, plus 9 times the fraction of columns with 3 and 9 sides, and if any columns have more than 9 sides, you just keep multiplying that fraction by increasing squares, starting with 16 as the multiple—and then take the square root of that. This ultimately gives a value of χₙ that will be exactly 0 if all columns are hexagons, &amp;lt;1 if all columns were 5-,6-, or 7-sided, exactly 1 if all columns were 5- and 7-sided, &amp;gt;1 and &amp;lt;2 if all columns were 4-, 5-, 6- 7-, and 8-sided, etc.&lt;/p&gt;&#xA;&lt;p&gt;—&lt;/p&gt;&#xA;&lt;p&gt;All figures in this answer are from:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Budkewitsch &amp;amp; Robin. (1994). &lt;em&gt;Modelling the evolution of columnar joints.&lt;/em&gt; Journal of Volcanology and Geothermal Research, 59(3), 219–239. &lt;a href=&quot;https://doi.org/10.1016/0377-0273(94)90092-2&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/0377-0273(94)90092-2&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;But see also:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Phillips et al. (2013). &lt;em&gt;The formation of columnar joints produced by cooling in basalt at Staffa, Scotland.&lt;/em&gt; Bulletin of Volcanology, 75(6), 715. &lt;a href=&quot;https://doi.org/10.1007/s00445-013-0715-4&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1007/s00445-013-0715-4&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Goehring &amp;amp; Morris. (2008). &lt;em&gt;Scaling of columnar joints in basalt.&lt;/em&gt; Journal of Geophysical Research, 113(B10), B10203. &lt;a href=&quot;https://doi.org/10.1029/2007JB005018&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1029/2007JB005018&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Morris. (2014). &lt;em&gt;Cracking the Giant’s Causeway with a Tabletop Experiment&lt;/em&gt; [Lecture Recording]. University of Toronto; YouTube. &lt;a href=&quot;https://youtu.be/c3TpGtUZEjc&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://youtu.be/c3TpGtUZEjc&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="24948" LastActivityDate="2023-05-31T06:23:35.457" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25235" PostTypeId="2" ParentId="25233" CreationDate="2023-05-31T08:26:17.777" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2021EF002334&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Explicit Calculations of Wet-Bulb Globe Temperature Compared With Approximations and Why It Matters for Labor Productivity&lt;/em&gt;&lt;/a&gt; might help explain what's going on.&lt;/p&gt;&#xA;&lt;p&gt;Liljegren's method appears to be calculation intense. It involves three equations, the two main ones are for T&lt;sub&gt;w&lt;/sub&gt; &amp;amp; T&lt;sub&gt;g&lt;/sub&gt;, equations 3 &amp;amp; 5. The equations needs to be solved by iteration.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MWEhg.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MWEhg.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;  &lt;span class=&quot;math-container&quot;&gt;$..............(3)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ULNEw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ULNEw.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;  &lt;span class=&quot;math-container&quot;&gt;$..............(4)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TUwdC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TUwdC.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;  &lt;span class=&quot;math-container&quot;&gt;$..............(5)$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;By ignoring direct sunlight &amp;amp; wind speed, the web page you link to is simplifying things &amp;amp; producing an approximation; something similar to calculating sW BGT, equation 1.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aOCIK.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aOCIK.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;    &lt;span class=&quot;math-container&quot;&gt;$.............(1)$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-05-31T08:26:17.777" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25236" PostTypeId="1" CreationDate="2023-05-31T08:34:50.060" Score="1" ViewCount="83" Body="&lt;p&gt;I'm working with ERA5 weather data and am trying to understand some wind &amp;amp; temperature patterns that I'm seeing in my statistics. In order to do that I'd like to compare with some point observations (weather stations). My work requires hourly data of at least temperature, wind velocity and direction reaching back at least 1 year (ideally 10). I'm looking mainly for information from Europe but am open to data from other regions. The amount of data I need is fairly limited since I'd filter only certain days.&lt;/p&gt;&#xA;&lt;p&gt;I've looked around but was unable to find a source with transparent access to such data. The closest I could find is WeatherUnderground (e.g.: &lt;a href=&quot;https://www.wunderground.com/dashboard/pws/ITOULO102/table/2023-05-30/2023-05-30/daily&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.wunderground.com/dashboard/pws/ITOULO102/table/2023-05-30/2023-05-30/daily&lt;/a&gt;), however there doesn't seem to be an API and there are some issues with the data (discretized wind direction for example).&lt;/p&gt;&#xA;&lt;p&gt;So my question: Is there something better available? A register of weather stations (official or private) that provides data access as described above?&lt;/p&gt;&#xA;" OwnerUserId="27444" LastActivityDate="2024-02-27T03:08:36.060" Title="Historic weather station data with hourly temporal resolution" Tags="|meteorology|wind|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25237" PostTypeId="2" ParentId="25236" CreationDate="2023-05-31T14:36:32.337" Score="0" Body="&lt;p&gt;I suggest you check out the &lt;a href=&quot;https://www.ecad.eu/dailydata/index.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;ECAD&lt;/a&gt; for European stations and the &lt;a href=&quot;https://www.dwd.de/EN/climate_environment/cdc/cdc_node_en.html;jsessionid=0DDD1E09A38F075C396C02C6020AA834.live11053&quot; rel=&quot;nofollow noreferrer&quot;&gt;DWD&lt;/a&gt; (German Weather Service). Both have some kind of ftp/open access.&lt;/p&gt;&#xA;" OwnerUserId="28529" LastActivityDate="2023-05-31T14:36:32.337" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25239" PostTypeId="2" ParentId="25236" CreationDate="2023-06-02T01:52:25.113" Score="0" Body="&lt;p&gt;I don't know of an API particularly, but I've dabbled around sites like &lt;a href=&quot;https://ncei.noaa.gov/data/global-hourly/access&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCEI&lt;/a&gt;, &lt;a href=&quot;https://mesonet.agron.iastate.edu/request/download.phtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Iowa Environmental Mesonet&lt;/a&gt; (from Iowa State), and &lt;a href=&quot;https://coolwx.com/userobs&quot; rel=&quot;nofollow noreferrer&quot;&gt;CoolWx&lt;/a&gt; (for PWS obs) and found some use from them on these topics.  Hopefully this is a start towards better info on this topic.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastActivityDate="2023-06-02T01:52:25.113" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25240" PostTypeId="1" CreationDate="2023-06-03T20:11:58.947" Score="1" ViewCount="165" Body="&lt;p&gt;Chernozem soils, called mollisols in the Americas, are black-colored soils containing a high percentage of humus (4% to 16%) and high percentages of phosphorus and ammonia compounds. Many earthworms contribute to the good soil structure and the qualities of the soil. Biodiversity and the abundance of organisms is high, and they are active at greater depths than in other soils. Such soils also contains a lot of calcium, so they do not easily become acidic. They are typical of grasslands in continental climate belts with cold winters, rainy springs and hot summers.&lt;/p&gt;&#xA;&lt;p&gt;As discussed on this SE site, a major theory about their formation links them to the fine mineral material left after glaciation: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/10176/how-can-poor-tropical-soils-be-enriched-by-biological-means&quot;&gt;How can poor tropical soils be enriched by biological means?&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;These soils are the most productive in the world. They account for one quarter of the world's total soils. They can be linked to Ukraine's role as a major breadbasket for the world. Before the current war (which started in February 2022) Ukraine produced 40% of global wheat and 47% of global sunflower oil, from around 1% of the globe's arable land. This can be linked to the motivations of the current conflict there with Russia.&lt;/p&gt;&#xA;&lt;p&gt;Can we generate new chernozem soil? What glaciers have done, we could now do mechanically. High soil carbon and humus can be generated, like with biochar and vermiculture. There may be limits in relation to biodiversity with temperature and humidity ranges. But can new chernozem be generated, where it can be sustained?&lt;/p&gt;&#xA;&lt;p&gt;This could ease conflicts over food and agricultural land. And &lt;a href=&quot;https://regenerationinternational.org/4p1000/&quot; rel=&quot;nofollow noreferrer&quot;&gt;substantially contribute to the draw down of carbon for climate targets&lt;/a&gt;. It also seems like we would want soil like this to successfully colonise Mars. Can we make it? Is anyone doing so, or trying to?&lt;/p&gt;&#xA;&lt;p&gt;I would note for comparison, anthropogenic &lt;a href=&quot;https://en.wikipedia.org/wiki/Terra_preta&quot; rel=&quot;nofollow noreferrer&quot;&gt;terra preta&lt;/a&gt;, in the tropical Amazon Basin.&lt;/p&gt;&#xA;&lt;p&gt;Seaweeds like giant kelp are also an interesting source of nutrients, that could help mop up agricultural run-off of phosphorus in particular, and be directed towards soil improvement.&lt;/p&gt;&#xA;" OwnerUserId="29026" LastEditorUserId="6298" LastEditDate="2023-06-04T02:54:36.457" LastActivityDate="2023-06-04T02:54:36.457" Title="Is it possible/effective to synthetically produce chernozem soil?" Tags="|soil|soil-science|anthropogenic|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25241" PostTypeId="1" CreationDate="2023-06-03T22:57:01.830" Score="3" ViewCount="73" Body="&lt;p&gt;I found nearly nothing about &lt;a href=&quot;https://en.wikipedia.org/wiki/Boesmansgat&quot; rel=&quot;nofollow noreferrer&quot;&gt;this sinkhole&lt;/a&gt; online. Apparently the cave has water dating back thousands of years.&lt;/p&gt;&#xA;&lt;p&gt;From where did this water come from.  Is it just rain? And how dirty is the water now?&lt;/p&gt;&#xA;" OwnerUserId="29027" LastEditorUserId="6298" LastEditDate="2023-06-04T10:42:12.143" LastActivityDate="2023-06-04T10:42:12.143" Title="How was the Boesmansgat Cave in South Africa formed?" Tags="|geology|hydrogeology|underground-water|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25242" PostTypeId="1" CreationDate="2023-06-04T03:59:49.277" Score="1" ViewCount="54" Body="&lt;p&gt;Since Mars core does not function like Earths does, would a planetary core &amp;quot;kick-starting and maintaining&amp;quot; device be needed in order to produce a magnetosphere required to preserve the oxygen needed for life?&lt;/p&gt;&#xA;" OwnerUserId="29028" LastActivityDate="2023-06-04T05:31:00.330" Title="Terraforming and maintaining a habitable atmosphere on Mars" Tags="|atmosphere|core|mars|oxygen|magnetosphere|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25243" PostTypeId="2" ParentId="25242" CreationDate="2023-06-04T05:31:00.330" Score="2" Body="&lt;p&gt;It depends on what gases one wants the atmosphere to contain. Mars has a lower gravitational acceleration than Earth, mainly due to is smaller size. This lower level of gravity, combined with the smaller size reduces the escape velocity for Mars, compared to Earth.&lt;/p&gt;&#xA;&lt;p&gt;Gases with smaller molecular weights, such as hydrogen H&lt;sub&gt;2&lt;/sub&gt; and helium He (with molecular weights of 2 and 4 respectively), will &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmospheric_escape&quot; rel=&quot;nofollow noreferrer&quot;&gt;escape&lt;/a&gt; anyway because they will more easily attain &lt;a href=&quot;https://en.wikipedia.org/wiki/Escape_velocity&quot; rel=&quot;nofollow noreferrer&quot;&gt;escape velocity&lt;/a&gt;, with or without the protection of a magnetosphere.&lt;/p&gt;&#xA;&lt;p&gt;Gases with heavier &lt;a href=&quot;https://en.wikipedia.org/wiki/Standard_atomic_weight&quot; rel=&quot;nofollow noreferrer&quot;&gt;molecular weights&lt;/a&gt; such as oxygen O&lt;sub&gt;2&lt;/sub&gt; (32), carbon dioxide CO&lt;sub&gt;2&lt;/sub&gt; (44) and nitrogen N&lt;sub&gt;2&lt;/sub&gt; (28) would receive some assistance from a magnetosphere that reduced atmospheric erosion from cosmic radiation.&lt;/p&gt;&#xA;&lt;p&gt;Read:&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;a href=&quot;https://geosci.uchicago.edu/%7Ekite/doc/Catling2009.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;The escape of planetary atmospheres&lt;/a&gt;&lt;/em&gt; and &lt;a href=&quot;https://physics.stackexchange.com/questions/615311/what-is-this-atmospheric-escape-chart-actually-showing&quot;&gt;What is this atmospheric escape chart actually showing?&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-06-04T05:31:00.330" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25244" PostTypeId="1" CreationDate="2023-06-04T06:19:56.340" Score="2" ViewCount="64" Body="&lt;p&gt;At a triple junction plate boundary there are three tectonic plates meeting. We have plenty of examples of these boundaries on Earth, notably the &lt;a href=&quot;https://en.wikipedia.org/wiki/Afar_Triple_Junction&quot; rel=&quot;nofollow noreferrer&quot;&gt;Afar Triple Junction&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Mendocino_Triple_Junction&quot; rel=&quot;nofollow noreferrer&quot;&gt;Mendocino Triple Junction&lt;/a&gt;, and the extinct &lt;a href=&quot;https://en.wikipedia.org/wiki/South_Greenland_Triple_Junction&quot; rel=&quot;nofollow noreferrer&quot;&gt;South Greenland Triple Junction&lt;/a&gt;. The majority of these junctions are divergent. But what if two of the three boundaries were convergent?&lt;/p&gt;&#xA;&lt;p&gt;I am currently working on a fantasy world but thought this question was more appropriate for this SE. This is the triple junction I am asking about.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1CmGx.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1CmGx.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The arrows that go under the colored lines are where the subducting is. The salmon line is convergent and the mint line is divergent.&lt;/p&gt;&#xA;&lt;p&gt;I was wondering if it was possible for a plate to both subduct another plate and also be subducted on basically the same boundary.&lt;/p&gt;&#xA;" OwnerUserId="29030" LastEditorUserId="29030" LastEditDate="2023-06-04T11:59:21.087" LastActivityDate="2023-06-04T12:20:09.690" Title="Can a tectonic plate subduct under one plate while another plate subducts under it along the same boundary?" Tags="|geophysics|plate-tectonics|planetary-science|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25245" PostTypeId="2" ParentId="25244" CreationDate="2023-06-04T12:11:22.383" Score="1" Body="&lt;h2&gt;On a large scale yes.&lt;/h2&gt;&#xA;&lt;p&gt;On a small scale you mostly get a complex mess of micro-plates created by the diverse forces.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hjK6I.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hjK6I.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ff4jA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ff4jA.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;A triple junction of any type of plate interaction can form, Japan has an all subduction triple junction.&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2023-06-04T12:20:09.690" LastActivityDate="2023-06-04T12:20:09.690" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25246" PostTypeId="1" CreationDate="2023-06-04T16:39:48.460" Score="3" ViewCount="91" Body="&lt;p&gt;&lt;em&gt;Blue hour&lt;/em&gt; is a part of nautical twilight when sky is very blue. This blueness appears because of Chappuis absorption of reddish light in stratospheric ozone.&lt;/p&gt;&#xA;&lt;p&gt;At later stages of nautical twilight, near the horizon around the solar azimuth there's a glowing blob of colors changing from reddish-orange to pale yellow to white (which is an interplay between Chappuis absorption, Rayleigh inscattering, and extinction) and fading to background blue (which exists due to multiple scattering), like in the following photo:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/R78ph.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/R78ph.jpg&quot; alt=&quot;Ladoga photo&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The photo above was taken from 60.3°N 32.6°E, on the shore of the Ladoga lake on 2019-04-14 at 21:47 UTC+3. (Ignore the W and NW markers, they are the remainders of my manual reprojection from fisheye to perspective, I forgot to remove them when saving.) So far so good, seems to make sense and also to match a simulation via CalcMySky in Stellarium more or less after increasing exposure of the screenshot:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZCghM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZCghM.jpg&quot; alt=&quot;Stellarium screenshot&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now, when I watch sunsets from Mauritius (20.4°S 57.4°E), both by naked eyes and using my camera, the nautical twilight always appears to be pinkish. The sky around the zenith does have some hints of blue, but generally everything, especially the bright blob near the horizon, is nothing like the photo from Ladoga or the simulation in Stellarium. Here's how this pink twilight looks, captured on 2023-05-30 at 18:25 UTC+4:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kLobq.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kLobq.jpg&quot; alt=&quot;Photo from Mauritius&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Note that this is not what's called afterglow (whose exact reasons are looked for in &lt;a href=&quot;https://earthscience.stackexchange.com/q/22859/12360&quot;&gt;this question&lt;/a&gt;), the afterglow has already faded out by the time I watch this &amp;quot;nautical pinkness&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;I first suspected that this might be due to the difference in ozone column above Ladoga (~400 DU) vs Mauritius (~270 DU), but a simulation tells me that the difference in colors would be only in saturation of blue, retaining the same qualitative picture.&lt;/p&gt;&#xA;&lt;p&gt;So I wonder, what is the reason for such a drastic difference in twilight colors between the continent around Ladoga and the ocean around Mauritius? I'm interested in a detailed explanation, so that I could make a new model of atmosphere and reproduce this pinkness.&lt;/p&gt;&#xA;" OwnerUserId="12360" LastActivityDate="2023-06-04T16:39:48.460" Title="Why does the blue hour look pink when watched from an isolated island?" Tags="|atmosphere|atmospheric-radiation|upper-atmosphere|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="25248" PostTypeId="1" CreationDate="2023-06-05T10:34:30.603" Score="8" ViewCount="5278" Body="&lt;p&gt;I am wondering if there are alternative ways to study glaciers apart from obtaining a PhD. I would be glad to build a career around glaciology, however, with the issues in regards to my PhD, a new Ph.D. with a supportive research group or a new career option altogether feels like an alternative. I was wondering if there are jobs in which I can get training to excel and also learn about glaciers.&#xA;I am confused on how to look for job positions that can satisfy my hunger to learn about glaciers (instead of doing it through PhD)&#xA;Thanks&lt;/p&gt;&#xA;" OwnerUserId="28184" LastActivityDate="2023-06-08T22:08:19.967" Title="Is PhD the only way to study glaciers?" Tags="|glaciology|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="25250" PostTypeId="2" ParentId="25248" CreationDate="2023-06-05T14:52:06.707" Score="14" Body="&lt;p&gt;I'm a glaciologist; my career path started as an undergrad in astronomy and then a Master's and Ph.D. in geophysics. However, many other paths lead to glaciology, often starting from geology, geography, physics, math, computer science, and many other fields. People who study glaciers usually do it in academia or private companies.&lt;/p&gt;&#xA;&lt;p&gt;For an academic path, I would say that a Ph.D. is almost mandatory. Some people have managed to work as research assistants for a long time without it, but that is very difficult. At least in North America, and it is probably the same in Europe.&lt;/p&gt;&#xA;&lt;p&gt;The other option is to seek to study glaciers in private companies, and in that case, you don't necessarily need a Ph.D. These companies are usually in the business of environmental impact assessments and water resources, often linked to hydroelectric power, mining or dam operations, and building.&#xA;Many countries perform academic research on glaciers. However, the private companies I mention usually exist only in countries with many glaciers and those industries.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastEditorUserId="953" LastEditDate="2023-06-08T20:22:49.787" LastActivityDate="2023-06-08T20:22:49.787" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25251" PostTypeId="2" ParentId="25248" CreationDate="2023-06-05T22:26:14.123" Score="13" Body="&lt;p&gt;The answer to your question lies in what you yourself expect to get out of &amp;quot;studying glaciers&amp;quot;. The traditional way is of course through a PhD and to become a specialist on some aspect of glaciology. However, one can study  glaciers from other perspectives than to advance the science itself. You can become a scientific communicator taking deeper science issues and communicating it to the general public. You can of course become some form of technical staff to help scientists to obtain data that leads to new insights. To be short, there are numerous avenues to pursue depending on your own backrguond and preferences.&lt;/p&gt;&#xA;&lt;p&gt;If you in fact want to advance the science itself, I sincerely doubt that you will be able to contribute much without specializing in some subfield and purssue a doctorate. Advancing science is a highly specialized effort that does require deep knowledge in a specific field and possibly one or several related field apart from knowledge about analysing and communicating new findings.&lt;/p&gt;&#xA;&lt;p&gt;In the end all contrubitions count so the desired degree of contribution to the field of glaciology will be personal and can be achieved by several means. No avenue is to be underestimated but at the same time not all will lead to major steps in understanding. Hence you need to consider what your potential will be in the grander scheme of things and pursue whatever avenue may be feasible.&lt;/p&gt;&#xA;&lt;p&gt;One aspect that can be of interest to contemplate is that the term &lt;em&gt;glaciologist&lt;/em&gt; is not as specific as e.g. optomologist or other professional specialist terms. Thus anyone can essentially call them a &lt;em&gt;glaciologist&lt;/em&gt;, it does not formally require a PhD. As inadequate as this may seem it is the reality so when you study glaciers you may call yourself a glaciologist but in essence the expertise lies in the level of your education and experience beyond a PhD.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="81" LastEditDate="2023-06-08T22:08:19.967" LastActivityDate="2023-06-08T22:08:19.967" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25254" PostTypeId="1" CreationDate="2023-06-06T16:35:29.527" Score="1" ViewCount="81" Body="&lt;p&gt;I have hourly-observed gross primary production data with the unit as µmol m&lt;sup&gt;-2&lt;/sup&gt; s&lt;sup&gt;-1&lt;/sup&gt;, how can I convert it to daily data with unit of gC/m&lt;sup&gt;2&lt;/sup&gt;/day?&#xA;The data is like this:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;2011-01-01 02:00:00        -0.0&#xA;2011-01-01 05:00:00        -0.0&#xA;2011-01-01 06:00:00        -0.0&#xA;2011-01-01 07:00:00        -0.0&#xA;2011-01-01 08:00:00        -0.0&#xA;2011-01-01 10:00:00   -0.019085&#xA;2011-01-01 13:00:00        -0.0&#xA;2011-01-01 15:00:00        -0.0&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;I guess I need to convert µmol to mol by dividing 10&lt;sup&gt;6&lt;/sup&gt;, then multiply by the molecular weight of carbon (12). After that, I need to convert the s&lt;sup&gt;-1&lt;/sup&gt; to per day by multiplying 3600*24, but do I need to sum over all data in 2011-01-01 or take the mean value because GPP is a flux data?&lt;/p&gt;&#xA;" OwnerUserId="14056" LastEditorUserId="2470" LastEditDate="2023-06-07T01:51:12.140" LastActivityDate="2023-06-07T01:51:12.140" Title="How to convert hourly measured GPP from µmol m-2 s-1 to daily data with unit of gC/m2/day?" Tags="|climate-models|co2|greenhouse-gases|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25255" PostTypeId="1" AcceptedAnswerId="25258" CreationDate="2023-06-06T21:49:49.293" Score="2" ViewCount="41" Body="&lt;p&gt;I am trying to get data of atmospheric temperature, wind intensity and/or atmospheric pressure for a specific region of the sea, since I have ocean bottom pressure data from a fixed instrument (lat,long), so I need to compare it with other variables. I have read in many articles that it could be obtained from satellite data. Can anyone help me with how to do that or guide me how to get the series? As you know it is not possible for a specific point in the sea, but the data for a given region (grid) works very well.&lt;/p&gt;&#xA;" OwnerUserId="27360" LastEditorUserId="2470" LastEditDate="2023-06-08T01:14:15.290" LastActivityDate="2023-06-08T01:14:15.290" Title="How to download atmospheric/oceanographic data for a given region in the sea?" Tags="|meteorology|oceanography|temperature|weather-satellites|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25256" PostTypeId="1" CreationDate="2023-06-07T04:29:44.977" Score="1" ViewCount="18" Body="&lt;p&gt;I have plotted wind speed and wind direction of scatsat data but wind barbs representing wind direction are plotted random (not in ordered manner.How to rectify this problem?&lt;a href=&quot;https://i.stack.imgur.com/rOV9F.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rOV9F.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29045" LastActivityDate="2023-06-07T04:29:44.977" Title="Unable to plot wind barbs of scatsat data in a ordered way" Tags="|meteorology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25257" PostTypeId="1" CreationDate="2023-06-07T04:58:42.677" Score="2" ViewCount="21" Body="&lt;p&gt;So I am working with the USGS data on salinity of various River reaches in the United States and not every reach mapped has been tested. Is there an accepted model for inferring the salinity of reaches given that you only have data of portions of the network? What is the information I would need for a such predictions?&lt;/p&gt;&#xA;&lt;p&gt;Edit:&lt;/p&gt;&#xA;&lt;p&gt;Let me rephrase. Imagine a table with the following information:&lt;/p&gt;&#xA;&lt;p&gt;Column 1: a complete set of reach codes for the River network.&#xA;Column 2: the reach directly upstream from the reach in column 1&#xA;Column 3: the main reach the reaches in columns 1 and 2 all flow back into—a main reach being defined as a reach that empties into an ocean/lake/other terminal body of water&#xA;Column 4: the mean salinity of each reach in column 1 for a period of time with null Values for many reaches that do not have any observations.&#xA;Column 5: the time span for the date available in column 4&lt;/p&gt;&#xA;&lt;p&gt;Now given these criteria, do I have enough to make estimates for the information in column 4 given if my goal is to be accurate enough to classify the river as fresh, brackish, saline? If not, what other data would be useful to arrive at a reasonable set of estimates?&lt;/p&gt;&#xA;" OwnerUserId="29046" LastEditorUserId="29046" LastEditDate="2023-06-07T23:07:44.497" LastActivityDate="2023-06-07T23:07:44.497" Title="Seeking guidance on predicting salinity of River network with incomplete data" Tags="|models|rivers|salinity|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25258" PostTypeId="2" ParentId="25255" CreationDate="2023-06-07T09:48:56.173" Score="2" Body="&lt;p&gt;If you want satellite data, you could use the &lt;a href=&quot;https://www.copernicus.eu/en/copernicus-satellite-data-access&quot; rel=&quot;nofollow noreferrer&quot;&gt;Copernicus system&lt;/a&gt;, which won't, however, provide you with the required variables, but the measured variables directly AFAIK (irradiance in various bandwidths).&lt;/p&gt;&#xA;&lt;p&gt;The usual approach would be to use reanalysis data, which you can get from the various organisations providing it like ERA5 from the &lt;a href=&quot;https://cds.climate.copernicus.eu/#!/home&quot; rel=&quot;nofollow noreferrer&quot;&gt;CDS&lt;/a&gt; or &lt;a href=&quot;https://www.psl.noaa.gov/data/reanalysis/&quot; rel=&quot;nofollow noreferrer&quot;&gt;NCEP&lt;/a&gt; from NOAA.&lt;/p&gt;&#xA;" OwnerUserId="28529" LastActivityDate="2023-06-07T09:48:56.173" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25259" PostTypeId="1" CreationDate="2023-06-08T01:57:27.480" Score="6" ViewCount="226" Body="&lt;p&gt;The EGM96 geoid map depicts hypothetical sealevel due to gravitational variations on the Earth's surface:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/C9IIA.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/C9IIA.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Geoid#/media/File:Earth_Gravitational_Model_1996.png&quot; rel=&quot;noreferrer&quot;&gt;image source&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;It places one of the highest areas in the northern part of the Atlantic ocean.&lt;/p&gt;&#xA;&lt;p&gt;The gravitational map from the GRACE mission depicts gravitational acceleration due to the same variations on the Earth's surface:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MJNKd.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MJNKd.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Gravity_of_Earth#/media/File:Gravity_anomalies_on_Earth.jpg&quot; rel=&quot;noreferrer&quot;&gt;image source&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;It places an area of high acceleration in the northern part of the Atlantic ocean.&lt;/p&gt;&#xA;&lt;p&gt;In fact, all of the high sealevel areas correspond to areas of high gravitational acceleration.&lt;/p&gt;&#xA;&lt;p&gt;I would have expected the opposite.&lt;/p&gt;&#xA;&lt;p&gt;Why is this so? I am assuming the images are correct. Why would higher gravitational acceleration lead to higher sealevels instead of pulling the water closer to Earth's center and leading to lower sealevels? Or am I misreading the images?&lt;/p&gt;&#xA;" OwnerUserId="1080" LastActivityDate="2023-06-20T14:50:04.753" Title="Why is sealevel higher where gravity is higher?" Tags="|oceanography|gravity|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25260" PostTypeId="1" CreationDate="2023-06-08T13:35:14.163" Score="1" ViewCount="60" Body="&lt;p&gt;I was looking at a map of the distribution of mantle plumes, and was wondering if they could be residual material that was either brought here or affected by the Theia impact.&lt;/p&gt;&#xA;&lt;p&gt;It seems to me that this material would have a distinct temperature difference to the material around it, and that, at the scale and volumes we are talking about, it would take billions of years for the currents to achieve anything resembling equilibrium, if they ever did.&lt;/p&gt;&#xA;&lt;p&gt;It seems as though the impact might also on another note, be responsible for exactly WHERE, the mantle first hardened into a crust.&lt;/p&gt;&#xA;&lt;p&gt;Is it possible that the Theia impact was the single event most responsible for the specific evolution of the crust and mantle that we see today and throughout geological history, creating the initial drastic variation in the mantle temperature, the conditions under which the first and subsequent continents would form, and the currents of mantle plumes that rift the crust into the specific plates we have seen through history? And could that possibly help us extrapolate a more precise location of where on Earth that impact took place?&lt;/p&gt;&#xA;&lt;p&gt;Is there any formal speculation that has been done on this that someone could point me to?&lt;/p&gt;&#xA;" OwnerUserId="29054" LastActivityDate="2023-06-08T13:35:14.163" Title="Is the Theia impact partly responsible for the distribution of mantle plumes?" Tags="|geology|plate-tectonics|crust|geodynamics|mantle-plumes|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25261" PostTypeId="1" AcceptedAnswerId="25264" CreationDate="2023-06-09T10:40:09.013" Score="2" ViewCount="145" Body="&lt;p&gt;I live in Maryland.  I  bought a HEPA air purifier with automatic, smart sensor-based operation to help with things like particulates during the central Canada wildfires.&lt;/p&gt;&#xA;&lt;p&gt;The air purifier's integrated air quality sensors constantly monitor fine dust particles (PM2.5), CO&lt;sub&gt;2&lt;/sub&gt;, temperature and humidity. Its air quality sensors monitor room air quality throughout the day, adjusting fan speed and purification to the necessary level, saving energy when air cleaning is not needed. The air quality indicator projects a soft glow behind the air purifier to indicate current air quality, based on measurements from the internal air quality sensors.&lt;/p&gt;&#xA;&lt;p&gt;My purifier's air quality sensors circumstantiate that air quality is better at night; the purifier automatically slows down at night.&lt;/p&gt;&#xA;&lt;h4&gt;Why?&lt;/h4&gt;&#xA;&lt;h4&gt;Do the wildfires burn less at night? Or does less smoke wind down to the USA at night?  Or something else?&lt;/h4&gt;&#xA;" OwnerDisplayName="user29055" LastEditorUserId="6298" LastEditDate="2023-06-09T23:18:57.100" LastActivityDate="2023-06-10T05:18:27.040" Title="Central Canada wildfires in June 2023 — at night it seems like less smoke? Why?" Tags="|wildfire|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25263" PostTypeId="1" CreationDate="2023-06-10T02:34:43.843" Score="3" ViewCount="107" Body="&lt;p&gt;A (relatively) recent 'Sky &amp;amp; Telescope' magazine feature story mentioned how little carbon the Earth has, and how some scientists' models predict we should somehow have even less....&lt;/p&gt;&#xA;&lt;p&gt;So I looked it up, and sure enough, our planet is almost half oxygen (which seems weird enough), and only about 1 in 625 atoms is carbon....&lt;/p&gt;&#xA;&lt;p&gt;Is there a known reason(s) for this?&lt;/p&gt;&#xA;" OwnerUserId="20985" LastActivityDate="2023-06-19T23:23:33.187" Title="If the universe (and our galaxy) has about twice as many oxygen atoms as carbon ones, why does Earth have 300 times as many oxygen atoms as carbon?" Tags="|geochemistry|earth-history|crust|core|mantle|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25264" PostTypeId="2" ParentId="25261" CreationDate="2023-06-10T04:08:20.347" Score="2" Body="&lt;p&gt;Your air filter is not a good way to qualify the smoke in your area, since it will run based on the air quality inside your home which can vary quite differently than the outdoor air.  Select a nearby site at EPA's &lt;a href=&quot;https://fire.airnow.gov&quot; rel=&quot;nofollow noreferrer&quot;&gt;fire.airnow.gov&lt;/a&gt; site to see how air quality changed during the June 2023 wildfire smoke event in your region.&lt;/p&gt;&#xA;&lt;p&gt;I selected a few monitors in your state and pasted a representative one below.  It looks like the smoke got bad after midnight on June 7 and then again it got even worse after midnight on June 8. This phenomena could be due to a shallower boundary layer at night which kept smoke closer to the surface.  When you woke up in the morning it was probably quite smoky, but as the day progressed there was convective activity that kept more of the smoke aloft.&lt;/p&gt;&#xA;&lt;p&gt;Yes, wildfires usually burn less at night because temperatures are cooler.  However, wind, terrain, available fuels, and humidity play major roles in the dynamics of combustive activity in wildfires.&lt;/p&gt;&#xA;&lt;p&gt;The timing of smoke impacts is circumstantial to the meteorology and geographic locations of the source and receptor.  I wouldn't look for many patterns in the timing of the smoke effects that you experienced, since you are far away from the source with many dynamic meteorological phenomena in play.&lt;/p&gt;&#xA;&lt;p&gt;There are detailed satellite imagery with PM2.5 monitor overlay at &lt;a href=&quot;https://www.star.nesdis.noaa.gov/smcd/spb/aq/AerosolWatch/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Aerosol Watch&lt;/a&gt;, if you would like to see how the event progressed through time.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YNWOf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YNWOf.png&quot; alt=&quot;fire.airnow.gov pop-up&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2023-06-10T05:18:27.040" LastActivityDate="2023-06-10T05:18:27.040" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25266" PostTypeId="2" ParentId="10855" CreationDate="2023-06-12T01:58:05.283" Score="4" Body="&lt;p&gt;Most alkali and alkaline earth metals, especially the most abundant ones calcium, magnesium, potassium and sodium (list is alphabetical) exist in silicates. Silicic acid/hydrated silica is very weakly acidic whereas the alkali and alkaline earth hydroxides are moderately strong or fully strong bases; so the silicates should be expected to give basic products when released into water solution. If carbon dioxide is serving as the chemical erosion agent, the metals described here will turn it into soluble bicarbonate ions, which are basic in water. The reaction below with orthoclase feldspar is given as an example (based on combining chemical reactions given in &lt;a href=&quot;https://www2.tulane.edu/%7Esanelson/eens211/weathering&amp;amp;clayminerals.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www2.tulane.edu/~sanelson/eens211/weathering&amp;amp;clayminerals.htm&lt;/a&gt;):&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{\underset{orthoclase}{4KAlSi3O8} +4CO2 +6H2O-&amp;gt; 4 K^+ +4\underset{basic}{HCO3^-} +\underset{kaolinite clay}{Al4Si4O_{10}(OH)8} +8\underset{quartz}{SiO2}}$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="2470" LastEditDate="2023-06-13T02:06:15.223" LastActivityDate="2023-06-13T02:06:15.223" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25267" PostTypeId="2" ParentId="25263" CreationDate="2023-06-13T01:53:08.660" Score="4" Body="&lt;p&gt;As the comments suggest, there probably is no one factor, but a big one seems to be the gas and ice giants took most of the carbon away.&lt;/p&gt;&#xA;&lt;p&gt;In our Solar System as a whole, &lt;a href=&quot;https://www.physics.unlv.edu/%7Ejeffery/astro/solar_system/solar_composition.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;the primordial nebula had almost as much carbon as oxygen&lt;/a&gt;. However, during the accretion of the planets smaller objects, even including eventual neighborhood-clearing planets such as Earth, had only enough gravitational pull to retain nonvolatile substances. These include many oxides of elements such as alkali and alkaline earth metals, aluminum and silicon (lithophiles), not so many carbon-rich materials. Carbon remained largely as volatile compounds, mostly methane, and only the biggest objects at favorable positions were able to gather up these volatiles.&lt;/p&gt;&#xA;&lt;p&gt;So a disproportionate amount of carbon ended up in the atmospheres of the giant planets instead of the solid structures of most everything else. &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Jupiter&quot; rel=&quot;nofollow noreferrer&quot;&gt;Jupiter's atmosphere&lt;/a&gt;, for instance, has more carbon in the form of (predominantly) methane than oxygen in the form of (predominantly) water.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2023-06-19T23:23:33.187" LastActivityDate="2023-06-19T23:23:33.187" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25269" PostTypeId="1" AcceptedAnswerId="25272" CreationDate="2023-06-13T13:12:26.977" Score="1" ViewCount="72" Body="&lt;p&gt;Only half of anthropogenic CO2 emissions remain in the atmosphere. This is easy to check by comparing the rate of emissions against the rate of increase in atmospheric CO2.  I have read from various sources that the remainder is absorbed - roughly in equal proportions - by two sinks, namely the ocean and the biosphere (some sources just say &amp;quot;woodland&amp;quot;).  However, the total area of woodland globally has been shrinking for many decades.  My question is: how can woodland be a carbon sink when it is shrinking?&lt;/p&gt;&#xA;" OwnerUserId="29068" LastActivityDate="2023-06-14T08:57:02.247" Title="How can woodland be a carbon sink when it is shrinking?" Tags="|carbon|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25271" PostTypeId="2" ParentId="25259" CreationDate="2023-06-14T07:02:24.603" Score="-5" Body="&lt;p&gt;The geoid &lt;a href=&quot;https://web.archive.org/web/20230606041313/https://oceanservice.noaa.gov/facts/geoid.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;is a model of global mean sea level&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;If one were to remove the tides and currents from the ocean, it would&#xA;settle onto a smoothly undulating shape (rising where gravity is high,&#xA;sinking where gravity is low).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;On one hand, if gravity were to be constant, then the geoid would have no ondulations.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, gravity depends on crustal material densities, and oceanic crust is much denser than continental crust:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;high densities ---&amp;gt; high gravity above oceanic crust&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The geoid represents the equipotential height of the sea surface.&#xA;If a molecule is subject to the earth’s gravitational field, it has a potential energy associated, derived from being pulled toward the Earth.&lt;/p&gt;&#xA;&lt;p&gt;If in a certain place A there is a higher gravity than in B, a molecule of water in A must be at a higher level than in B to feel the same attractive gravitational force (i.e. at a bigger distance from the mass center of the earth, for visualization purposes assume that all the mass is centered in a point in the core of the Earth, but gravity can vary azimutally).&lt;/p&gt;&#xA;&lt;p&gt;See also &lt;a href=&quot;https://www.esri.com/news/arcuser/0703/graphics/geoid2_lg.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;this image&lt;/a&gt; from a company providing geogrpahical services.&lt;/p&gt;&#xA;" OwnerUserId="5887" LastEditorUserId="5887" LastEditDate="2023-06-20T14:50:04.753" LastActivityDate="2023-06-20T14:50:04.753" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="25272" PostTypeId="2" ParentId="25269" CreationDate="2023-06-14T08:57:02.247" Score="2" Body="&lt;p&gt;I agree that this kind of source and sink budgeting is a little bit misleading. The answer to your question is that the land use change you mentioned to be a source of CO2 is added to the anthropogenic CO2 emissions. And indeed it is about as large as the sink effect of the biosphere (check out the figure I found in a &lt;a href=&quot;https://public.wmo.int/en/resources/bulletin/from-atmospheric-observations-and-analysis-of-greenhouse-gases-emission-estimates&quot; rel=&quot;nofollow noreferrer&quot;&gt;WMO article&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OjkFq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OjkFq.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="28529" LastActivityDate="2023-06-14T08:57:02.247" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25273" PostTypeId="1" AcceptedAnswerId="25275" CreationDate="2023-06-14T09:07:58.077" Score="1" ViewCount="53" Body="&lt;p&gt;Near an old fire-trail I found a single fist-size igneous rock that I identified (as an amateur geologist) as belonging to a formation that is not known of in the area but is known to occur in the neighbouring district, although not common there. Naturally I was interested if there was an outcrop and looked for more float samples, but twenty minutes of searching yielded no more samples of the kind. My question is, how reliable are float samples? Is there probably an outcrop? Or assuming my ID was correct, could I just have been that the bulldozer that cut the road all those years ago came directly from the small part of the neighbouring district where these rocks are found. Or did the bulldozer move it from elsewhere on the hill, but there still probably is an outcrop in the immediate vicinity.&lt;/p&gt;&#xA;&lt;p&gt;Apologies for the rather specific (and long-winded) question, I understand that this Stack Exchange is looking for more general questions, but I would just like to add if it was possible for an intrusive igneous rock such as syenite to be shed from quartz conglomerate? It seems unlikely to me, but that is the main formation above the spot where it was found and could explain its occurrence. (Should I have created a seperate question for this?)&lt;/p&gt;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="28926" LastActivityDate="2023-06-14T21:45:04.200" Title="How accurate are float samples when looking for outcrops?" Tags="|rocks|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25275" PostTypeId="2" ParentId="25273" CreationDate="2023-06-14T21:45:04.200" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Syenite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Syenite&lt;/a&gt; is a granite like igneous rock that is deficient in quartz. If it contains quartz the amount of quartz is less than 5 percent.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://geology.com/rocks/conglomerate.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Conglomerate&lt;/a&gt; is sedimentary rock that contains clasts (rock fragments - the sedimentary component) that have were once washed down a river and are held together by  quartz or calcite. The rock fragments (clasts) with the matrix of the conglomerate are &lt;strong&gt;rounded&lt;/strong&gt;, which indicates they tumbled down a river.&lt;/p&gt;&#xA;&lt;p&gt;The clasts within the conglomerate can be from a variety of different rock types, including: quartz or feldspar, quartzite, sandstone, limestone, granite, basalt, and gneiss. It is possible that syenite can be a component of a conglomerate, it depends on the local geology.&lt;/p&gt;&#xA;&lt;p&gt;Regarding the floater, with only one sample for an area it is difficult to tell, but is seems unlikely to indicate a local outcrop. As you indicate it may have been deposited there during road construction works.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-06-14T21:45:04.200" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25276" PostTypeId="1" CreationDate="2023-06-16T05:27:29.720" Score="3" ViewCount="139" Body="&lt;p&gt;If the goal were to cut the total amount of smoke in the air in half, how many&#xA;millions of dollars per year are we talking about here?  I envision hiring&#xA;hundreds of people to find fires before they spread, maybe with some high-tech&#xA;way of sensing heat from satellites...please just pick the most cost effective&#xA;solution.&lt;/p&gt;&#xA;" OwnerUserId="18294" LastActivityDate="2023-06-20T19:49:07.810" Title="What would it cost to stop Canada forest fires?" Tags="|forest|wildfire|canada|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25279" PostTypeId="2" ParentId="18596" CreationDate="2023-06-17T00:31:10.777" Score="1" Body="&lt;p&gt;National Geographic has a nice &lt;a href=&quot;https://education.nationalgeographic.org/resource/island/&quot; rel=&quot;nofollow noreferrer&quot;&gt;webpage&lt;/a&gt;, that explains:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;There are six major kinds of islands: continental (1), tidal (2), barrier (3), oceanic (4), coral (5), and artificial (6).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The article continues that when Pangaea broke up, &amp;quot;some large chunks of land split. These fragments of land became islands. Greenland and Madagascar are these type of continental islands.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;Referring to an image (below) of Pangaea (source: Amante, C. and Eakins, B. W. 2009), it is clear that Australia is it's own continental mass, while Greenland is a piece of a larger mass.  Despite Australia historically being referred to as an island country &amp;quot;&lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/B00W1WSFGQ&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;because of its lack of land borders&lt;/a&gt;&amp;quot;, it is &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_island_countries&quot; rel=&quot;nofollow noreferrer&quot;&gt;not an island&lt;/a&gt;.  There is a nice &lt;a href=&quot;https://en.wikipedia.org/wiki/Continent#Beyond_four_continents&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia article&lt;/a&gt; that explains:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Europeans discovered Australia in 1606, but for some time it was taken as part of Asia. By the late 18th century, some geographers considered it a continent in its own right, making it the sixth (or fifth for those still taking America as a single continent). In 1813, Samuel Butler wrote of Australia as &amp;quot;New Holland, an immense island, which some geographers dignify with the appellation of another continent&amp;quot; and the Oxford English Dictionary was just as equivocal some decades later. It was in the 1950s that the concept of Oceania as a &amp;quot;great division&amp;quot; of the world was replaced by the concept of Australia as a continent.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It's also important to consider that sea level has a major role in how much continental mass is &amp;quot;island&amp;quot;.  If you consider land bridges like the &lt;a href=&quot;https://en.wikipedia.org/wiki/Thule_Land_Bridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;Thule Bridge&lt;/a&gt;, one could postulate that Greenland has not always been an &amp;quot;island&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aiwbE.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aiwbE.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2023-06-17T04:24:37.810" LastActivityDate="2023-06-17T04:24:37.810" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="25280" PostTypeId="1" AcceptedAnswerId="25281" CreationDate="2023-06-17T02:00:01.897" Score="3" ViewCount="358" Body="&lt;p&gt;On October 4, 2010 a &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Ajka_alumina_plant_accident&quot; rel=&quot;nofollow noreferrer&quot;&gt;disaster&lt;/a&gt; started at a site in Ajka, Hungary. A &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Red_mud&quot; rel=&quot;nofollow noreferrer&quot;&gt;red mud&lt;/a&gt; reservoir near an alumina plant broke, and the toxic material moved through nature and on into the northern half of Devecser village and killed 10 people, injured 406 others, and destroyed a lot of trees and animals.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hZQTi.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hZQTi.png&quot; alt=&quot;Impact of Ajka&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I calculated the area of that reservoir to be about 25 hectares using &lt;a href=&quot;https://www.mapdevelopers.com/area_finder.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; site.&lt;/p&gt;&#xA;&lt;p&gt;Also, I calculated the maximum length and width of the flown red mud to be about 3 miles and 1 mile respectively (using Google Maps).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SANuXm.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SANuXm.jpg&quot; alt=&quot;Length of Ajka red mud&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;On the Wikipedia page for the Ajka disaster it's also stated that the volume of red mud was about 1,000,000 m&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt;, and the total area affected was about 40 km&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;That got my attention looking at a red mud reservoir near Hamburg. It has an area of about 1.45 km&lt;span class=&quot;math-container&quot;&gt;$^2$&lt;/span&gt;, and it is 28 miles far from Hamburg. Also, it's near an alumina plant in Stade.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Qarm0m.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Qarm0m.jpg&quot; alt=&quot;German red mud reservoir&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IQ711m.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IQ711m.jpg&quot; alt=&quot;German red mud area&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I don't know the depth of either reservoir.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;My question&lt;/strong&gt;: How far would the German red mud reservoir impact the nature around it if it was to break?&lt;/p&gt;&#xA;" OwnerUserId="29082" LastEditorUserId="6298" LastEditDate="2023-06-17T06:35:56.500" LastActivityDate="2023-09-11T08:27:51.097" Title="The impact of red mud near Hamburg" Tags="|environmental-protection|natural-disasters|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25281" PostTypeId="2" ParentId="25280" CreationDate="2023-06-17T08:40:00.110" Score="4" Body="&lt;p&gt;Based on the information presented, this question is unanswerable.&lt;/p&gt;&#xA;&lt;p&gt;What is the topography of the area the red mud dam is on? Flat, steep or somewhere in between? Are there any waterways nearby which could be inundated and send red mud farther down stream? Is there a delicate nature reserve nearby?&lt;/p&gt;&#xA;&lt;p&gt;What is the consistency of the red mud? How fluid is it? This will largely affect it flow characteristics. It won't have the consistency of water, so you it won't have an affect like the water from the &lt;a href=&quot;https://www.bbc.com/news/world-europe-65818705&quot; rel=&quot;nofollow noreferrer&quot;&gt;Khakova Dam burst&lt;/a&gt;. Similarly it won't have the consistency of dry rock and it will have a larger affect than the &lt;a href=&quot;https://www.abc.net.au/news/2023-06-17/swiss-landslide-misses-brienz-village-by-metres/102492026&quot; rel=&quot;nofollow noreferrer&quot;&gt;rock slide at Brienz in Switzerland&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, how do you expect the dam to fail, how will the wall break? Will it be a small breakage that releases a small amount of material over a prolonged period that can be easily dealt with, or will it be a massive collapse that releases a large amount of material in a very small amount of time releasing something akin to a tsunami or red mud at a high speed with a lot of energy - an uncontrollable catastrophe? Which of the four walls do you expect could break and how would the surface topography assist or hinder the flow of material from the dam?&lt;/p&gt;&#xA;&lt;p&gt;Does the company responsible for the dam currently have a 24/7 monitoring system that can warn it of a possible or impending wall failure? How quickly could it respond to such a situation and what could it do?&lt;/p&gt;&#xA;&lt;p&gt;What factors could affect the stability of the dam: seismic activity and seismic resistance of the the dam, terrorists with explosives or heavy machinery damaging a wall, heavy rain eroding a wall, excessive water ponding of water on top of the dam, weakening a wall, repeated periodic excessive wetting and drying of the dam?&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2023-06-18T01:18:29.457" LastActivityDate="2023-06-18T01:18:29.457" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25282" PostTypeId="1" AcceptedAnswerId="25284" CreationDate="2023-06-17T10:31:28.587" Score="1" ViewCount="87" Body="&lt;p&gt;I was surfing on Google Maps satellite mode and I found these odd objects in northern Bolivia&lt;a href=&quot;https://i.stack.imgur.com/uyeHq.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uyeHq.jpg&quot; alt=&quot;odd&quot; /&gt;&lt;/a&gt;. They look like turned-on TVs, but the largest of them has a length of about 48 yards!&lt;/p&gt;&#xA;&lt;p&gt;Can anyone identify these? Maybe they are mirrors?&lt;/p&gt;&#xA;&lt;p&gt;The coordinates: -10.297946, -66.350233&lt;/p&gt;&#xA;" OwnerUserId="29082" LastEditorUserId="6298" LastEditDate="2023-06-17T18:16:30.667" LastActivityDate="2023-06-17T18:16:30.667" Title="What are these lighted shapes on Google Maps?" Tags="|satellite-oddities|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25283" PostTypeId="2" ParentId="25276" CreationDate="2023-06-17T10:35:19.427" Score="3" Body="&lt;p&gt;What makes you thing money can solve such a problem?&lt;/p&gt;&#xA;&lt;p&gt;Canada, like most other countries that are prone to wildfires does not have enough fire fighting personnel to attend to all such fires. Presently, Canada has &lt;a href=&quot;https://www.ctvnews.ca/canada/firefighters-from-u-s-south-africa-to-battle-canada-s-unprecedented-fires-1.6422509&quot; rel=&quot;nofollow noreferrer&quot;&gt;signed agreements&lt;/a&gt; to accept fire fighters from the USA,Mexico, Costa Rica, Australia, New Zealand and South Africa. Canada has 566 of its own fire fighters and so far has brought in 443 from the US, Australia and New Zealand. A current total of 1009. During the &lt;a href=&quot;https://en.wikipedia.org/wiki/2019%E2%80%9320_Australian_bushfire_season&quot; rel=&quot;nofollow noreferrer&quot;&gt;2019/20 catastrophic fires&lt;/a&gt;, Australia received assistance from: Canada, Fiji, France, Indonesia, Japan, Malaysia, New Zealand, Papua New Guinea. The Philippines, Singapore, United Arab Emirates, USA. It also utilized &lt;a href=&quot;https://www.aph.gov.au/About_Parliament/Parliamentary_Departments/Parliamentary_Library/pubs/rp/rp1920/Quick_Guides/AustralianBushfires&quot; rel=&quot;nofollow noreferrer&quot;&gt;6500 of its own defense force personnel&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Then there's the issue of fire fighting equipment and obtaining what is needed: trucks; &lt;strong&gt;water&lt;/strong&gt;; back burning equipment; water bombers; equipment for cutting line breaks: graders, bulldozers. Getting enough water to a fire could problematic. Access to remote areas, particularly in mountainous or heavy undulating terrain will also be difficult. Are there roads to such areas and are they in good condition. The rotation and rest of fire fighters is critically important.&lt;/p&gt;&#xA;&lt;p&gt;Weather conditions are critical: air temperature (particularly wet bulb temperature), wind speeds and directions, moisture content or dryness of the air, the possibility of the formation of &lt;a href=&quot;https://en.wikipedia.org/wiki/Fire_whirl&quot; rel=&quot;nofollow noreferrer&quot;&gt;fire tornadoes&lt;/a&gt; or &lt;a href=&quot;https://en.wikipedia.org/wiki/Flammagenitus_cloud&quot; rel=&quot;nofollow noreferrer&quot;&gt;pyrocumulus cloud&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Weather conditions during the preceding years also important, particularly if it encourages the growth of new forest vegetation, particularly undergrowth. If conditions are too favorable too much dry undergrowth can develop. The only way to remove it is by controlled burning during wetter, cooler periods. Knowing if such conditions exist requires monitoring.&lt;/p&gt;&#xA;&lt;p&gt;One of the unpleasant realities of fires on such a scale as they currently are in Canada is humans cannot extinguish the conflagration. Humans can attempt to prevent fires from escalating. Fires on such a scale are extinguished by either wet weather or they just burn out by running out of fuel.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-06-17T10:35:19.427" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25284" PostTypeId="2" ParentId="25282" CreationDate="2023-06-17T10:37:46.280" Score="9" Body="&lt;p&gt;The shiny objects are the metal roofs of buildings. The photos have been taken at a time when the roofs reflect much of the sunlight towards the camera.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-06-17T10:37:46.280" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25285" PostTypeId="1" CreationDate="2023-06-17T20:26:35.413" Score="17" ViewCount="8642" Body="&lt;p&gt;I had a discussion about this with my coworker. It appears that global warming (even up to +6K) has advantages:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;increased plant growth: increase in photosynthesis efficiency&lt;/li&gt;&#xA;&lt;li&gt;more water evaporation from oceans which will cause more rains even in dry places like Africa&lt;/li&gt;&#xA;&lt;li&gt;Warmer winters that will allow humans to grow more food. Greenland will become green again&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Only drawbacks I could find were:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;More power consumption in summer for AC, compensated by less power consumption in winter for warming&lt;/li&gt;&#xA;&lt;li&gt;Intense evaporation and temperature difference will cause strong winds and storms, but it will cause more rain in distant places which is better. Building advanced city drain systems like in Japan can mitigate this problem for cities&lt;/li&gt;&#xA;&lt;li&gt;Coast line change due to water level rise. Modern engineering allows the building of islands, and that technology will probably improve with technological progress&lt;/li&gt;&#xA;&lt;li&gt;Increase in power losses in electrical lines. For copper it's only 0.393%/K, also can be mitigated with usage of advanced modern insulators that enable higher voltages for energy transfer&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;The drawbacks look small to me, and I also describe how they can be compensated. Are there any more?&lt;/p&gt;&#xA;&lt;p&gt;So why is global warming bad?&lt;/p&gt;&#xA;" OwnerUserId="29086" LastEditorUserId="7064" LastEditDate="2023-06-20T12:32:21.587" LastActivityDate="2023-06-21T02:01:15.833" Title="Why is global warming bad?" Tags="|climate-change|" AnswerCount="10" CommentCount="23" ClosedDate="2023-06-24T10:30:02.010" ContentLicense="CC BY-SA 4.0" />
  <row Id="25286" PostTypeId="2" ParentId="25285" CreationDate="2023-06-18T01:04:05.000" Score="37" Body="&lt;p&gt;Global warming is colloquially referred to as the human-made warming of the climate that would not have otherwise occurred without the industrial revolution.  The greenhouse effect, which is the mechanism that leads to warming, is in fact necessary for life on earth since the temperature of Earth would be too cold without it.  The amount of carbon in the atmosphere has fluctuated greatly over millions of years, naturally, but we are greatly affecting it now.  From &lt;a href=&quot;https://www.nrdc.org/stories/global-warming-101&quot; rel=&quot;nofollow noreferrer&quot;&gt;Global Warming 101&lt;/a&gt;, the detrimental effects of a rapidly warming Earth are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;more frequent extreme weather events&lt;/li&gt;&#xA;&lt;li&gt;disappearing glaciers, early snowmelt, and severe droughts will cause more dramatic water shortages and increase the risk of wildfires&lt;/li&gt;&#xA;&lt;li&gt;rising sea levels will lead to even more coastal flooding&lt;/li&gt;&#xA;&lt;li&gt;forests, farms, and cities will face troublesome new pests, heat waves, heavy downpours, and increased flooding. All of these can damage or destroy agriculture and fisheries.&lt;/li&gt;&#xA;&lt;li&gt;disruption of habitats such as coral reefs and alpine meadows could drive many plant and animal species to extinction.&lt;/li&gt;&#xA;&lt;li&gt;allergies, asthma, and infectious disease outbreaks will become more common due to increased growth of pollen and the spread of conditions favorable to pathogens and mosquitoes.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;If we take a look at your list, we should make some revisions to the advantages:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;increased plant grow (increase in photosynthesis efficiency)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Increases in CO2 don't benefit photosynthesis in hotter/drier conditions.  Plant stress due to water availability and extreme heat are more influential than increases in CO2.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;more water evaporation from oceans that will cause more rains even in dry places like Africa&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;That sounds nice, but actually the increased water moisture and heat in the atmosphere lead to more extreme weather events and can shift seasonal weather patterns under different climate conditions.  This means more floods and tornadoes and hurricanes, etc.  That water doesn't infiltrate into the soil like seasonal rain does.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Warmer winters that will allow grow more food (Greenland will become green again)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The loss of ice from glaciers leads to sea-level rise and loss of coastland cities due to flooding events.  Not sure if they will want to move to Greenland.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="-1" LastEditDate="2023-06-21T02:01:15.833" LastActivityDate="2023-06-21T02:01:15.833" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25287" PostTypeId="2" ParentId="25285" CreationDate="2023-06-18T08:53:34.723" Score="26" Body="&lt;p&gt;Our current economy is a rather fragile thing. Even a small war in central Europe has caused supply chain issues and painful inflation around the whole world. Any kind of major disruption would be disastrous, where by &lt;em&gt;disastrous&lt;/em&gt; I mean cause major reductions in the standard of living for a large part of the world's population.&lt;/p&gt;&#xA;&lt;p&gt;Eight of the top 10 largest cities in the world - Tokyo, Mumbai, New York City, Shanghai, Lagos, Los Angeles, Calcutta and Buenos Aires - are on or near the coast. At best uncontrolled climate change would require massive spending to create flood defences, and at worst it would render large parts of these cities uninhabitable and displace hundreds of millions of people. I think you would agree this counts as &lt;em&gt;major disruption&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The problem is not that we could not construct a modern civilisation in a warmer world. As you point out, the issues caused by higher temperatures are not necessarily problems. If our society had developed from hunter gathers in a warmer climate we'd simple have built our cities farther inland. The problem is how we transition from our current state to a warmer world. We cannot just pick up New York and move it a few miles inland&lt;/p&gt;&#xA;" OwnerUserId="29089" LastActivityDate="2023-06-18T08:53:34.723" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25288" PostTypeId="1" CreationDate="2023-06-18T10:24:42.577" Score="1" ViewCount="46" Body="&lt;p&gt;I want to ask in a broader and clearer sense. What would you say are the types of natural disasters because it gets a bit confusing by reading from online data.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;By researching a lot - I have found are total 6 types:&#xA;-&amp;gt; Geophysical , meteorological , hydrological , biological , climatological , extraterrestrial , space ,&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Like under :&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;geophysical would come - volcanic eruptions , earthquakes.&lt;/li&gt;&#xA;&lt;li&gt;hydrological you can say comes - Tsunamis , floods , droughts etc&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;So like that….&lt;/p&gt;&#xA;&lt;p&gt;Now , I couldn’t like find all of them under a single section of page , book etc. So , am not sure if this is how we classify natural disasters and their types correctly. That’s why I want to learn and know exactly how do we classify them. How the tree of classification of their types are done.&lt;/p&gt;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="21823" LastActivityDate="2023-06-18T10:24:42.577" Title="What are the types of natural disasters?" Tags="|natural-disasters|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25289" PostTypeId="2" ParentId="25285" CreationDate="2023-06-18T10:48:30.550" Score="15" Body="&lt;p&gt;This is a question with a very wide scope and complex answers with much uncertainty. However, I have found &lt;a href=&quot;https://interactive.carbonbrief.org/impacts-climate-change-one-point-five-degrees-two-degrees/#&quot; rel=&quot;noreferrer&quot;&gt;Carbon Brief's interactive explainer&lt;/a&gt; a good starting point. This, however, has limited coverage of issues beyond 2C because it relies on published papers.&lt;/p&gt;&#xA;&lt;p&gt;If I understand you correctly, a rise of 6C over preindustrial levels would almost certainly have drastic consequences for humanity. That would almost certainly push the &lt;a href=&quot;https://www.nature.com/articles/s41561-021-00695-3.epdf?sharing_token=GlhdCWKHzTVtPw6MXhXIqNRgN0jAjWel9jnR3ZoTv0NOaanMDu5pDqxdq1CXrSgWHRP3sKswyDBh-YasxmQBGjjfSoy-MkRey9ANz6yLuR74IpAia5aYgmhJStmMqRbSzk5jPfzAeg_kULNg3ZqSHVvOV3hTVcFXxhm4vJPwqugKd_TGC3l8gGZY6wbec9PglM2u-WJwkSFb0i0dARYKnKGQhX4h9vl1NlTQz_EQIL_1Jtu_OVvPnzhaLEAy3pIJmLe1k9eHNqs_d1mLUxFTWg-ZEXJHgCMZvYgjeo_AFBqxF6EQIXD2_ukkR4OCRUPR&quot; rel=&quot;noreferrer&quot;&gt;wet-bulb temperature in the tropics over 35C&lt;/a&gt;, making large areas of the Earth's surface uninhabitable for all or part of the year.&lt;/p&gt;&#xA;" OwnerUserId="29090" LastActivityDate="2023-06-18T10:48:30.550" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25290" PostTypeId="1" CreationDate="2023-06-18T16:44:53.590" Score="1" ViewCount="54" Body="&lt;p&gt;I recently heard that the d98Mo isotope is not different from the d238U isotope in redox processes e.g. in black shale events. But I can't find any evidence except the figure from Zhang et al. unfortunately,&#xA;2018:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GeaLD.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GeaLD.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But I know that the correlation is not really recognisable and the explanation is missing:D Can you give me literature or have an explanation at hand?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2023-07-24T09:45:01.077" LastActivityDate="2023-07-24T09:45:01.077" Title="Co variance of isotopes in geochemical amplications" Tags="|geochemistry|isotopic|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25291" PostTypeId="2" ParentId="25285" CreationDate="2023-06-18T22:32:11.680" Score="15" Body="&lt;p&gt;Have you ever been at 47 degrees Celsius (118 F) outdoors? I have, and it is unbearable. Right now Arizona is at 41 C (106 F), 6 more degrees means 47 C. Plus those places already at 47 C will go to 53 C (127 F), making them worse than the Sahara desert. This is just the average; it will likely be worse in some places.&lt;/p&gt;&#xA;&lt;p&gt;Most people in the tropics will die or be forced to migrate. We are not speaking about your ordinary migratory pressure: making &lt;a href=&quot;https://metrocosm.com/peak-temperature-map/&quot; rel=&quot;noreferrer&quot;&gt;large areas of the globe&lt;/a&gt; inhospitable means that hundreds of millions of people will be displaced forcefully from their communities. Since there is not a lot of empty space on the globe, this will cause huge pressure on the rest of the world.&lt;/p&gt;&#xA;&lt;p&gt;Mind you, 1/3 of people &lt;a href=&quot;https://www.nationalgeographic.org/encyclopedia/tropics/&quot; rel=&quot;noreferrer&quot;&gt;live in the tropics&lt;/a&gt;, where temperatures of 45+ C are not uncommon. Most of the population cannot afford air conditioning even now, and the cost of cooling a house at 53 C would probably be thousands of dollars per month in the best possible scenario. In countries where average income per capita is &lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_countries_by_GDP_(nominal)_per_capita&quot; rel=&quot;noreferrer&quot;&gt;a few thousand dollars per year&lt;/a&gt; this is out of the question. Supposing the electric grid could stand it. That is without ever leaving your house.&lt;/p&gt;&#xA;&lt;p&gt;So it looks pretty bad to me, even without taking into account the hurricanes, the extreme droughts, the sea raises, the loss of natural habitats and all the other nasty predicted effects from climate change. Sure, a few areas like Greenland may become nice and warm, but it is not enough to offset all the bad things.&lt;/p&gt;&#xA;" OwnerUserId="29094" LastEditorUserId="29094" LastEditDate="2023-06-19T10:17:23.060" LastActivityDate="2023-06-19T10:17:23.060" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="25292" PostTypeId="2" ParentId="25276" CreationDate="2023-06-19T05:45:34.843" Score="0" Body="&lt;p&gt;I think there may be a misconception about how fire is controlled in the forested wildland setting.  There are plenty of fire-detect tools out there, and we know where they are.  The problem is that when wildfires occur due to lightning, they can often be far from any access routes.  And, you can get dozens of fire starts overnight during a thunderstorm.  This makes it difficult to access and control the fires.  In reality, the real work needed to limit smoke during wildfire season (and wildfires themselves) is done in the off-season.  Prescribed burning and other forest management techniques are used when fire danger is low, which greatly helps to limit wildfire growth when fuels dry-up in the summer.  So, it is a long-term monetary commitment that is needed to manage all forested lands if we want to limit wildfires and smoke.  I don't know what that dollar amount is, but in general it is difficult to get government to fund something that doesn't have a direct/immediate monetary benefit.&lt;/p&gt;&#xA;&lt;p&gt;Without road access, it can be incredibly difficult to get the manpower and resources to the fire location.  Most of wildfire fire-fighting is done through containment, not &amp;quot;putting the fire out&amp;quot;, because it is not physically possible to fly enough airplanes to drop water and put out a fire that spans hundreds or thousands of acres.  The hard work of containing a fire is done on the ground.  You have to cut fuel breaks and do back burns so that the fire stays within a controlled perimeter and doesn't grow.  You also need experienced staff.  This is life and death work with very difficult physical demands, so you can't just &amp;quot;hire more people&amp;quot; one day when fires get out of hand.   When it gets bad across the region, fire fighters from other countries will be brought in to help.&lt;/p&gt;&#xA;&lt;p&gt;In general, decisions are made during wildfire season to focus resources that &amp;quot;extinguish&amp;quot; fires on threatened developed land and residences; because they are accessible and government wants to minimize property loss and loss of life.  The reality is that when it is wildfire season, we are waiting for the next rain event to do the work of extinguishing the fire.  In the meantime there is focused extinguishing efforts on protecting human life and property and containing fires that are accessible.  Please support federal land managers and fire fighters.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2023-06-19T06:13:59.877" LastActivityDate="2023-06-19T06:13:59.877" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25294" PostTypeId="2" ParentId="25285" CreationDate="2023-06-19T10:22:04.867" Score="11" Body="&lt;p&gt;Apart from sea level rise which will force billions to relocate, rising temperatures which will render large parts of the Earth uninhabitable by humans, a major problem is &lt;a href=&quot;https://www.ipcc.ch/report/ar6/wg1/chapter/chapter-11/&quot; rel=&quot;nofollow noreferrer&quot;&gt;extreme weather&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;If you shift a normal distribution, extreme values on the high end become &lt;em&gt;much&lt;/em&gt; more frequent.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0eQxE.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0eQxE.png&quot; alt=&quot;extreme values&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;a href=&quot;https://www.researchgate.net/figure/Probability-density-functions-PDF-for-simulations-daily-maximum-temperature-at_fig2_236116527&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Source&lt;/em&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(Note that due to changing dynamics, in some regions, cold extremes &lt;em&gt;can&lt;/em&gt; become more frequent — it's complicated)&lt;/p&gt;&#xA;&lt;p&gt;This is why, due to climate change, we are already seeing unprecedented droughts and fires &lt;em&gt;and&lt;/em&gt; unprecedented floods.  Just in the past five years, &lt;a href=&quot;https://www.moodys.com/web/en/us/about/insights/data-stories/reinsurers-mitigate-lower-profits.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;extreme weather caused 100 billion dollar in insured losses&lt;/a&gt; — that does not include uninsured losses.  Most of the world population are not insured against losses, and some extreme weather will become so frequent in some regions it becomes uninsurable.  A single hailstorm &lt;a href=&quot;https://www.cbc.ca/news/canada/calgary/calgary-hailstorm-costly-damage-1.5642317&quot; rel=&quot;nofollow noreferrer&quot;&gt;can cause more than 1 billion dollar in damage&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Apart from contributing to mass extinction and immense human suffering, climate change is &lt;strong&gt;expensive&lt;/strong&gt;.  Humans are extremely sedentary creatures, building dwellings lasting 3-15 generations or more and cities lasting 100+ generations.  Human civilisation thrived during the holocene, which had a remarkably stable climate.  We've messed that one up and entered the anthropocene, throwing away the best thing the planet has ever given us.  Could we survive in a warmer climate with more extreme weather?  As a species, probably.  It would be immensely expensive, and generations after us will curse us for making life in the next 50-1000 years much harder and more expensive than it might have been if we had acted sensibly.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2023-06-20T14:49:55.507" LastActivityDate="2023-06-20T14:49:55.507" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25295" PostTypeId="2" ParentId="25285" CreationDate="2023-06-19T10:33:20.147" Score="8" Body="&lt;h1&gt;Water Shortages&lt;/h1&gt;&#xA;&lt;p&gt;By now, the melting/retreat of glaciers is perhaps the most well-established proof of warming temperatures regardless of what you believe about weather satellites and the greenhouse effect. While glaciers don't directly provide much fresh water, they are a direct proof of average snowfall and winter temps. Shrinking glaciers obviously mean less snowfall, which means less meltwater, which means less freshwater feeding streams and rivers.&lt;/p&gt;&#xA;&lt;p&gt;A lot of agriculture depends not just on rain, but on these water sources, and reduced water availability is felt keenly, such as this case in &lt;a href=&quot;https://globalnews.ca/news/9773852/drought-alberta-stettler-county-agricultural-disaster/&quot; rel=&quot;noreferrer&quot;&gt;Alberta, CA&lt;/a&gt;. It's not just crops on farms that are suffering. Cattle depend widely on natural forage, so when there isn't enough water for wild grasses and shrubs, it affects the entire food chain/ecosystem.&lt;/p&gt;&#xA;&lt;p&gt;This isn't just one or two farms having trouble, either. The entire province declared a state of emergency due to the extremely dry conditions. If there are other farmers who are benefiting from better weather, they sure aren't crowing about it in the news cycle. Nor are investors shilling their shares to trump up demand. There is certainly no talk of a Greenland farming boom.&lt;/p&gt;&#xA;&lt;h1&gt;Wildfires&lt;/h1&gt;&#xA;&lt;p&gt;Fires need fuel. Trees work very hard to pull water out of the ground, transpiring it into the air as part of photosynthesis. This also has the secondary effect of lowering the average temperature around them (as anyone who has walked by a tree on a hot day can tell you vs. standing under a manmade shade). Healthy trees with a good water supply thus make for bad firewood and are very resistant to wildfires. On the other hand, hotter weather often means less rainfall, and more importantly, dehydration of all plants, as the higher temperatures increase the water capacity of the atmosphere and thus reduce the relative humidity. For dead plant matter normally undergoing natural composting, this means instead of being food for bacteria and fungi, it becomes food for wildfires.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.noaa.gov/noaa-wildfire/wildfire-climate-connection&quot; rel=&quot;noreferrer&quot;&gt;NOAA&lt;/a&gt; assesses that climate change has been the primary driver of increased fires in the recent record years. It's quite amusing that you call greater evaporation a &lt;em&gt;good&lt;/em&gt;, when it's quite obvious that it's a &lt;em&gt;serious bad&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;h1&gt;Thawing Permafrost&lt;/h1&gt;&#xA;&lt;p&gt;You mention higher winter temps as a positive effect, which totally ignores the fact that both humans and nature depend on cold winter temperatures. Normally, the fossil fuel industry would support the &amp;quot;warming isn't bad&amp;quot; argument, but anyone who lives in Alaska can tell you that the oil industry relies heavily on permafrost for arctic drilling. The year-round ice makes for a reliable and sturdy surface for roads and buildings. When it melts &lt;em&gt;the &lt;a href=&quot;https://www.epa.gov/climate-indicators/climate-change-indicators-permafrost&quot; rel=&quot;noreferrer&quot;&gt;oil industry&lt;/a&gt; is negatively impacted&lt;/em&gt;. On top of that, organic matter that was frozen for possibly thousands of years now releases methane into the atmosphere as the permafrost melts, further accelerating climate change.&lt;/p&gt;&#xA;&lt;h1&gt;Decreased Nutrition&lt;/h1&gt;&#xA;&lt;p&gt;While elevated CO2 will indeed cause plants to grow larger, on average, what it mainly does is increase the carbohydrate content and cause larger leaves. What it doesn't do is increase the nutritional content of the plants. So carb-heavy crops like wheat get a net gain, but most other crops become &lt;em&gt;less nutritious&lt;/em&gt; because they are bigger, but with the same amount of nutrients (like protein and vitamins). That's because nutrient production is usually limited by soil composition, and higher CO2 doesn't magically cause increased nitrogen or trace minerals in the soil. You might have to eat 20% more watermelon or orange to the get same nutrients you do today, which is wasted metabolic energy for digestion. Not a win.&lt;/p&gt;&#xA;&lt;p&gt;As far as increased wheat productivity, with the rise of gluten sensitivity, I hardly think that increasing our carb production is the pathway to a healthier society. We are already overflowing with carbs, and an excess of carbs could easily be described as the primary driver of obesity.&lt;/p&gt;&#xA;&lt;h1&gt;Conclusion&lt;/h1&gt;&#xA;&lt;p&gt;Literally all of your &amp;quot;pros&amp;quot; are actually &amp;quot;cons&amp;quot; when you take a closer look. We don't have to wait 50 years to tell whether climate change is going to be a net positive or not. We can see it in action today. And the only beneficiaries of it that I have seen so far are mining interests that want to explore the Arctic (Russia in particular) now that there are so many more ice-free days (and perhaps it will become permanently ice-free).&lt;/p&gt;&#xA;" OwnerUserId="21024" LastActivityDate="2023-06-19T10:33:20.147" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25297" PostTypeId="2" ParentId="25285" CreationDate="2023-06-20T07:49:56.680" Score="5" Body="&lt;p&gt;Regarding your first point: &amp;quot;increased CO&lt;sub&gt;2&lt;/sub&gt; causes increase in photosynthesis efficiency&amp;quot;. While this is true, there is a caveat:&lt;/p&gt;&#xA;&lt;p&gt;Plants do indeed grow faster, but at the expense of decreased protein and micronutrients (&lt;a href=&quot;https://www.frontiersin.org/articles/10.3389/fpls.2020.01267/full&quot; rel=&quot;noreferrer&quot;&gt;see e.g. here&lt;/a&gt;).&#xA;So while one may get more of C3 crops (rice, wheat, ...) they are then of lower quality, at least regarding protein content (&amp;quot;carbon dilution effect&amp;quot;). So one partly loses what was gained. There seems to be a direct causal link, because C4 plants which do not benefit from elevated CO&lt;sub&gt;2&lt;/sub&gt; leaves do not show the carbon dilution effect (&lt;a href=&quot;https://www.frontiersin.org/articles/10.3389/fpls.2020.01267/full&quot; rel=&quot;noreferrer&quot;&gt;see Introduction here&lt;/a&gt;))&lt;/p&gt;&#xA;&lt;p&gt;Perhaps for some plants this effect is not strong, or can be mitigated with special treatment. I am not sure if everything is already well understood and if solutions to the problems can be found, if the problems are so bad that they need mitigation. But perhaps it is not valid to label increased CO&lt;sub&gt;2&lt;/sub&gt; an advantage per se (a betterdscription would probably be &amp;quot;potential advantage&amp;quot; or just not list it as advantage).&lt;/p&gt;&#xA;" OwnerUserId="29114" LastEditorUserId="2470" LastEditDate="2023-06-20T09:34:52.933" LastActivityDate="2023-06-20T09:34:52.933" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25299" PostTypeId="2" ParentId="25285" CreationDate="2023-06-20T14:30:45.043" Score="3" Body="&lt;p&gt;In short, because it is happening quicker than any possible &amp;quot;adaptation&amp;quot; of life to it, putting a lot of biological stress on the environment.&lt;/p&gt;&#xA;&lt;p&gt;For the humans, it is bad because our infrastrucutre is hyper-specialized and very fragile.&lt;/p&gt;&#xA;&lt;p&gt;Much of our human infrastructure has been built with the water table and the sea level being at a certain level, as well as much of the agricultural infrastructure is dependent and optimized for narrow temperature and humidity ranges at predefined latitudes.&lt;/p&gt;&#xA;" OwnerUserId="5887" LastActivityDate="2023-06-20T14:30:45.043" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25302" PostTypeId="2" ParentId="25285" CreationDate="2023-06-20T17:26:23.130" Score="1" Body="&lt;p&gt;We refer to it as &amp;quot;Climate Change&amp;quot; now rather than &amp;quot;Global Warming&amp;quot; to reflect how places will get extremely hot and/or extremely cold sometimes sporadically with little warning. The balance and the whole ecosystem of how our world operates has been upset.&lt;/p&gt;&#xA;&lt;p&gt;For instance in the UK we had &amp;quot;Beast of the East&amp;quot; (&lt;a href=&quot;https://inews.co.uk/news/when-was-the-beast-from-the-east-what-happened-in-2018-and-if-similar-uk-weather-is-coming-2186341&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://inews.co.uk/news/when-was-the-beast-from-the-east-what-happened-in-2018-and-if-similar-uk-weather-is-coming-2186341&lt;/a&gt;) that caused disruption due to extremely cold weather.. sometimes -10oC... then a record heat wave later.&lt;/p&gt;&#xA;&lt;p&gt;Climate Change does not cause all bad weather of course.. but it can make bad weather 20 times more likely : &lt;a href=&quot;https://www.theguardian.com/environment/2022/oct/05/climate-crisis-made-summer-drought-20-times-more-likely-scientists-find&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.theguardian.com/environment/2022/oct/05/climate-crisis-made-summer-drought-20-times-more-likely-scientists-find&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This flip flop of extreme cold and extreme heat makes it very difficult for people to heat and cool (for instance in the UK we do not predominantly have airconditioning in our homes) and can lead to incredibly expensive gas bills in winter.&lt;/p&gt;&#xA;&lt;p&gt;People's homes are being flooded that were never previously likely to be flooded and in other places people's homes are going up in flames with fires that would never have been imagined before.&lt;/p&gt;&#xA;&lt;p&gt;Then there's all the species of animals and plants that are being wiped out because it's too hot. Corals are bleaching and then dying in the seas.. &lt;a href=&quot;https://www.earthday.org/how-climate-change-is-threatening-our-species/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.earthday.org/how-climate-change-is-threatening-our-species/&lt;/a&gt; You might not specifically care about bees etc, but if you are relying on them to pollinate plants that ultimately end up as being your food this all puts everything into chaos.&lt;/p&gt;&#xA;&lt;p&gt;The death of plants, people and animals is more than an inconvenience and scientists refer to certain &amp;quot;tipping points&amp;quot; (examples at &lt;a href=&quot;https://www.theguardian.com/environment/2022/sep/08/world-on-brink-five-climate-tipping-points-study-finds&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.theguardian.com/environment/2022/sep/08/world-on-brink-five-climate-tipping-points-study-finds&lt;/a&gt;) that trigger at different thresholds of climate change... i.e. A certain amount of the ice caps melting is predicted to raise the sea level to a certain level that entire countries will be under water.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;71% of the 504 extreme weather events and trends included in the map were found to be made more likely or more severe by human-caused&#xA;climate change.&lt;/li&gt;&#xA;&lt;li&gt;9% of events or trends were made less likely or less severe by climate change, meaning 80% of all events experienced some human&#xA;impact. The remaining 20% of events and trends showed no discernible&#xA;human influence or were inconclusive.&lt;/li&gt;&#xA;&lt;li&gt;Of the 152 extreme heat events that have been assessed by scientists, 93% found that climate change made the event or trend more&#xA;likely or more severe.&lt;/li&gt;&#xA;&lt;li&gt;For the 126 rainfall or flooding events studied, 56% found human activity had made the event more likely or more severe. For the 81&#xA;drought events studied, it’s 68%.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.carbonbrief.org/mapped-how-climate-change-affects-extreme-weather-around-the-world/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.carbonbrief.org/mapped-how-climate-change-affects-extreme-weather-around-the-world/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29120" LastEditorUserId="29120" LastEditDate="2023-06-20T17:31:40.767" LastActivityDate="2023-06-20T17:31:40.767" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25304" PostTypeId="2" ParentId="25285" CreationDate="2023-06-20T21:45:15.350" Score="2" Body="&lt;p&gt;Don't forget ocean acidification, increased CO2 leads ot acidification of the ocean, which kills coral and other photosynthetic life, so you get a net LOSS of photosynthesis.&lt;/p&gt;&#xA;&lt;p&gt;Also it does not necessarily lead to much increase in photosynthesis on land. 1 extreme heat often reduces photosynthetic efficiency and 2 few plants are limited by CO2, limitation by nitrogen is more common so increased CO2 does not get you more photosynthesis.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://pubmed.ncbi.nlm.nih.gov/15143433/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://pubmed.ncbi.nlm.nih.gov/15143433/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/s41598-019-40620-8&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/s41598-019-40620-8&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.frontiersin.org/articles/10.3389/fmars.2019.00322/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.frontiersin.org/articles/10.3389/fmars.2019.00322/full&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://news.climate.columbia.edu/2022/01/27/how-climate-change-will-affect-plants/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://news.climate.columbia.edu/2022/01/27/how-climate-change-will-affect-plants/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2023-06-20T21:45:15.350" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25305" PostTypeId="1" AcceptedAnswerId="25308" CreationDate="2023-06-21T20:29:52.910" Score="3" ViewCount="84" Body="&lt;p&gt;In  the book by Jonathan E. Martin &amp;quot;Mid-Latitude Atmospheric Dynamics - A First Course&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;the continuity equation for isentropic coordinates is derived by applying conservation  of mass:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fJt6a.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fJt6a.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\frac{d}{dt}(\frac{\partial p}{\partial \theta})  + \frac{\partial p}{\partial \theta} \frac{\partial u}{\partial x}+ \frac{\partial p}{\partial \theta} \frac{\partial v}{\partial y}+\frac{\partial p}{\partial \theta} \frac{\partial}{\partial \theta}(\dot \theta)=0$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now, following the book, by expanding the total derivative on the left I would get:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\underbrace{\frac{\partial}{\partial t}(\frac{\partial p}{\partial \theta})  + u \frac{\partial }{\partial x}(\frac{\partial p}{\partial \theta}) + v \frac{\partial }{\partial y}(\frac{\partial p}{\partial \theta}) + \frac{d \theta}{dt}\cdot \frac{\partial }{\partial \theta}(\frac{\partial p}{\partial \theta})}_{\frac{d}{dt}(\frac{\partial p}{\partial \theta})} + \underbrace{\frac{\partial p}{\partial \theta} \frac{\partial u}{\partial x}+ \frac{\partial p}{\partial \theta} \frac{\partial v}{\partial y}}_{\frac{\partial p}{\partial \theta} \vec \nabla \cdot \vec V}+\frac{\partial p}{\partial \theta} \frac{\partial}{\partial \theta}(\dot \theta)=0$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Using divergence operator, this has 6 terms, however, in the final result given by the book&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SC1AP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SC1AP.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I would miss the term&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\frac{d \theta }{d t} \cdot  \frac{\partial }{\partial \theta}(\frac{\partial p}{\partial \theta})$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Why? I see no reason why this term is skipped.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/iMZCR.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/iMZCR.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21047" LastActivityDate="2023-06-22T09:30:29.333" Title="Why is one term missing in the derivation of continuity equation in isentropic coordinates?" Tags="|meteorology|atmosphere|atmosphere-modelling|fluid-dynamics|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25307" PostTypeId="2" ParentId="25147" CreationDate="2023-06-22T08:42:06.093" Score="5" Body="&lt;p&gt;The assumptions are either observably valid, tested, or logical. When creationists say they are uncertain they are obscuring the fact that these assumptions are almost always routinely tested.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;starting parent-daughter ratios: these are in some cases (40Ar/39Ar, Rb/Sr) determined by isochron analysis, and in others tested by dual decay chains 238U-&amp;gt;206Pb and 237U-&amp;gt;208Pb using concordia analysis. This is completely routine as part of any dating technique and a non-linear relationship on an isochron plot, or a discordant dataset on a concordia diagram invalidates the assumption for that analysis.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;closed system behaviour: Whether a system is closed depends on environmental conditions. Numerous experiments are dedicated to understanding the limits of open system behaviour (= &lt;a href=&quot;https://en.wikipedia.org/wiki/Closure_temperature&quot; rel=&quot;noreferrer&quot;&gt;closure temperature&lt;/a&gt;) by measuring diffusivities.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;U-Pb &lt;a href=&quot;https://en.wiktionary.org/wiki/concordia_diagram&quot; rel=&quot;noreferrer&quot;&gt;concordia diagrams&lt;/a&gt; or isochron plots can be used to evaluate open or closed system behaviour for every analysis. In some cases the open system behaviour of different daughter isotopes in different minerals is used to evaluate &lt;a href=&quot;https://en.wikipedia.org/wiki/Thermochronology&quot; rel=&quot;noreferrer&quot;&gt;temperature evolution through time&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;Observable changes to decay rates are &lt;a href=&quot;https://en.wikipedia.org/wiki/Radioactive_decay#Changing_rates&quot; rel=&quot;noreferrer&quot;&gt;negligible&lt;/a&gt; (&amp;lt;1%) and have not been observed for isotopes used in geochronology. The creationist argument is essentially that decay rates were faster in the past to account for why geochronology yields an age of the earth of 4.5 billion years as opposed to 6000 years.&#xA;The difference is a factor of 750 000, never mind a few %.&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_internal_heat_budget&quot; rel=&quot;noreferrer&quot;&gt;About 50% of Earth's heat budget results from radioactive decay&lt;/a&gt;. If decay rates were 750 000 times higher, as much more heat would have been produced from decay that Earth would be in a vapor or plasma state, and not forming any kind of rock. We do have crustal rocks with geochronological ages of &lt;a href=&quot;https://en.wikipedia.org/wiki/Oldest_dated_rocks&quot; rel=&quot;noreferrer&quot;&gt;~4 billion years&lt;/a&gt;, meaning they were cool enough to crystallise zircon when they formed.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Summary- these assumptions are important, and they are routinely tested. The constancy of decay rates is difficult to test but is observationally constant between the different isotopes used in geochronology. The creationist assumption that all decay rates changed by a factor of 750 000 is absurd.&lt;/p&gt;&#xA;" OwnerUserId="4783" LastEditorUserId="2470" LastEditDate="2023-06-23T02:46:28.927" LastActivityDate="2023-06-23T02:46:28.927" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25308" PostTypeId="2" ParentId="25305" CreationDate="2023-06-22T09:30:29.333" Score="3" Body="&lt;p&gt;Potential temperature is conserved considering adiabatic processes and thus: &lt;span class=&quot;math-container&quot;&gt;$\text{d} \theta/\text{d}t = 0$&lt;/span&gt;. Otherwise the term needs to be retained.&lt;/p&gt;&#xA;&lt;p&gt;On page 84 (just below figure 4.3) they say that given an adiabatic process, parcel flow is constrained to a surface of potential temperature, so I think they just assume adiabatic flow.&lt;/p&gt;&#xA;" OwnerUserId="18833" LastActivityDate="2023-06-22T09:30:29.333" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25309" PostTypeId="2" ParentId="240" CreationDate="2023-06-22T10:16:53.013" Score="-2" Body="&lt;p&gt;A molten core is essential for the survival of life on Earth as we know it. The molten core of our planet is responsible for generating a magnetic field that shields the surface from harmful solar radiation and cosmic rays. Without this protective magnetic field, the Earth's atmosphere would be stripped away, and life would likely not be able to survive.&lt;/p&gt;&#xA;&lt;p&gt;In addition, the molten core plays a critical role in regulating the Earth's climate and maintaining a stable environment for life to thrive. Without the heat generated by the core, the Earth's surface would be much colder and less hospitable to life. The movement of the molten material in the core also helps to drive the motion of the tectonic plates, which plays a critical role in the cycling of nutrients and the regulation of the carbon cycle, which are both important for life on Earth.&lt;/p&gt;&#xA;" OwnerUserId="29136" LastActivityDate="2023-06-22T10:16:53.013" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25310" PostTypeId="2" ParentId="25227" CreationDate="2023-06-22T22:24:23.687" Score="10" Body="&lt;p&gt;To answer the original question about CO&lt;sub&gt;2&lt;/sub&gt; saturation, I'll describe spectral absorption.  Each gas in the atmosphere absorbs light at specific wavelengths, and some wavelengths are absorbed more than others.  The spectral absorption of CO&lt;sub&gt;2&lt;/sub&gt; is shaped like a V.  With no CO&lt;sub&gt;2&lt;/sub&gt;, the radiative spectrum of Earth would resemble a black-body.  When CO&lt;sub&gt;2&lt;/sub&gt; is added, this 'V' is pushed into the black-body spectrum, making a notch.  At present concentrations, the bottom of this notch is 'saturated', meaning it hits the bottom.  As more CO&lt;sub&gt;2&lt;/sub&gt; is added, the V is pushed further down into the radiative spectrum.  The bottom certainly remains saturated, but the edges of the notch continue to erode.&lt;/p&gt;&#xA;&lt;p&gt;There are other problems with this paper.&lt;/p&gt;&#xA;&lt;p&gt;Figure 6 in the paper shows that doubling the atmospheric concentrations of CO&lt;sub&gt;2&lt;/sub&gt;, N&lt;sub&gt;2&lt;/sub&gt;O, and CH&lt;sub&gt;4&lt;/sub&gt; would cause increases in radiative forcing.  They claim these increases are negligible, but they are not.  Their own data show that doubling CO&lt;sub&gt;2&lt;/sub&gt; would cause an additional increase of 3.74 W/m&lt;sup&gt;2&lt;/sup&gt;.  To put this in perspective, all radiative forcing to date, referenced to the start of industrial times in 1750, is 3.4 W/m&lt;sup&gt;2&lt;/sup&gt;.  Doubling N2O would cause an additional 1.99 W/m&lt;sup&gt;2&lt;/sup&gt;.  Doubling CH&lt;sub&gt;4&lt;/sub&gt; would cause an additional 1.12 W/m&lt;sup&gt;2&lt;/sup&gt;.  These numbers are not &amp;quot;negligible&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;Figure 15 in the paper presents their model's results, side-by-side with satellite measurements.  To the naked eye, they look good.  However, when they are plotted against each other, they do not match.  As their model is meant to study spectral absorption, you might think their model would match the satellite data in the &amp;quot;spectral window&amp;quot; where no absorption occurs.  It does not.  Their model must be scaled by +5.6%, -3.9%, and -12.5% for the Sahara, Mediterranean, and Antarctic datasets, respectively.  Even after adjusting the model to match the satellite data, the model overestimates the amount of outgoing radiation.  This infers that the Earth is staying cool, when in fact it is retaining heat.  The discrepancy is on the order of 3-5% globally, which is quite large.&lt;/p&gt;&#xA;&lt;p&gt;In answering this question, I have used the data presented in the paper itself.  As the authors did not provide the raw data, I used software to digitize the graphical data.  My results may be off by a decimal place, but they are in the ballpark.&lt;/p&gt;&#xA;" OwnerUserId="29140" LastEditorUserId="2470" LastEditDate="2023-06-23T02:40:29.513" LastActivityDate="2023-06-23T02:40:29.513" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25311" PostTypeId="1" CreationDate="2023-06-23T12:01:17.283" Score="0" ViewCount="15" Body="&lt;p&gt;I am working with an LES (Large-Eddy Simulation) model, and I want to define the vertical profile of specific humidity (qt) based on a given temperature profile (thl). However, I am not sure how to calculate the specific humidity lapse rates that correspond to the temperature profile I set.&lt;/p&gt;&#xA;&lt;p&gt;My aim is to see the onset of clouds in my domain therefore my diagnostics are liquid water content, liquid water path and cloud fraction. I have tested so far a linearly stratified potential temperature profile and I see how it changes throughout the simulation run with an amount of sensible heat flux and moisture from the ground(figure).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3wihC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3wihC.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I want to perform a sensitivity run and check my diagnostics while I change the initial potential temperature profile (stable, neutral and unstable). However, I am not sure how to change the corresponding moisture profile for each case.&lt;/p&gt;&#xA;&lt;p&gt;e.g. Keeping a relatively low RH throughout the profile (&amp;lt;50%), how will the moisture profile change with regards to temperature?&lt;/p&gt;&#xA;" OwnerUserId="29145" LastActivityDate="2023-06-23T12:01:17.283" Title="Setting specific humidity vertical profile in an LES" Tags="|meteorology|atmosphere-modelling|simulation|planetary-boundary-layer|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25312" PostTypeId="2" ParentId="25229" CreationDate="2023-06-24T14:13:51.347" Score="2" Body="&lt;p&gt;Consider, instead of looking at an Earth map of Magnetic Declination, looking at a map of the Earth's magnetic field:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/37I1k.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/37I1k.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Now trace a line across North America in such a way as to intersect the magnetic lines at locations where they are perpendicular to true north.  You should end up tracing out the green line in the image posted in the question.&lt;/p&gt;&#xA;&lt;p&gt;Read on if that sounded confusing: Instead, find and circle the points on the lines in the map of the Earth's magnetic field where the curve of the line is perpendicular to an imaginary line drawn from the true North Poll to that point. When done, the points should all be on the green lines in the map in the posted question above.&lt;/p&gt;&#xA;" OwnerUserId="29148" LastActivityDate="2023-06-24T14:13:51.347" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25314" PostTypeId="1" CreationDate="2023-06-24T17:04:02.387" Score="5" ViewCount="330" Body="&lt;p&gt;Or better yet, how WAS it done? I understand that depth sounding was done with a lead weight attached to a long rope or wire, but how were the leadsmen able to tell when the lead weight reached the bottom? Especially when the water is far too deep to see the bottom. Part of what inspired the question was the story of the first depth soundings at Challenger deep done in 1875. So I am inquiring about the exact details of how depth sounding was done.&lt;/p&gt;&#xA;" OwnerUserId="17742" LastActivityDate="2023-07-12T10:54:55.510" Title="How is bathymetry done without sonar?" Tags="|bathymetry|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25315" PostTypeId="1" CreationDate="2023-06-24T19:53:06.527" Score="2" ViewCount="136" Body="&lt;p&gt;I need some help with my grandson's school homework: can someone describe what's the phenomena behind the creation of these small stones at the plateau´s foot? why &amp;amp; how are they created?&lt;/p&gt;&#xA;&lt;p&gt;No big deal - an answer for dummies would be great!&lt;/p&gt;&#xA;&lt;p&gt;Thanks in advance to all! Cheers&lt;img src=&quot;https://i.stack.imgur.com/1bCqf.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/p&gt;&#xA;" OwnerUserId="29152" LastActivityDate="2023-07-12T10:38:17.100" Title="How the small stones in this photo are created?" Tags="|geology|" AnswerCount="2" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="25317" PostTypeId="1" CreationDate="2023-06-24T22:19:34.203" Score="-4" ViewCount="67" Body="&lt;p&gt;Is cern/DARPA using all 30,000 HYDRON COLLIDERS scattered around earth being used to manipulate weather, natural disasters, like activating the 48 volcanoes that are erupting that started at the end of May till present. Each one is a different size baking me think the large HYDRON COLLIDER is the main control of the network of the colliders that may or not be connected to the Darpa field of antennas that manipulate the weather. On YouTube that photos of groups of animals running in circles for 12 days or more without food or water in different continents different states different countries everywhere around the planet there are animals running in circles for days without water or food. Do you have anything to say about that. Because Moses animals run off the Earth's magnetic field of them migrating where they go and the rain is true because they're confused because you guys are pulsating the Earth with the hydron colliders. The animals are all on YouTube. You should check it out it's wild.&lt;/p&gt;&#xA;" OwnerUserId="29153" LastActivityDate="2023-06-25T03:12:34.357" Title="Is the 30,000 HYDRON COLLIDERS around this planet being used to manipulate Earth's magnetic fields to create eruptions, earthquakes,ECT" Tags="|volcanology|" AnswerCount="1" CommentCount="2" ClosedDate="2023-06-25T09:52:57.033" ContentLicense="CC BY-SA 4.0" />
  <row Id="25318" PostTypeId="2" ParentId="25314" CreationDate="2023-06-25T01:52:42.523" Score="5" Body="&lt;p&gt;When a weight is suspended from a rope and is hanging either in mid air or mid water the rope is in tension and is tight. In this situation, when the weight is lifted and lowered the rope remains tight at all times. The tension in the rope can be felt at all times. If the rope is coiled onto a winder, as the weight falls the rope unwinds from the coil.&lt;/p&gt;&#xA;&lt;p&gt;When the weight hits the bottom, the rope will eventually stop unwinding from the coil and become slack. The rope has no tension. To determine the depth to be bottom from the length of rope slowly wind the rope back onto the coil until it first become tense and there is no slack in the rope. The length of rope at that point is the depth of the sea floor.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-06-25T01:52:42.523" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25319" PostTypeId="2" ParentId="25317" CreationDate="2023-06-25T03:12:34.357" Score="2" Body="&lt;p&gt;Hadron colliders are &lt;a href=&quot;https://home.cern/resources/faqs/facts-and-figures-about-lhc&quot; rel=&quot;nofollow noreferrer&quot;&gt;expensive&lt;/a&gt; to construct and operate. As a consequence only &lt;a href=&quot;https://en.wikipedia.org/wiki/Hadron_collider&quot; rel=&quot;nofollow noreferrer&quot;&gt;five have been constructed&lt;/a&gt;, not 30 000. The construction cost of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Large_Hadron_Collider&quot; rel=&quot;nofollow noreferrer&quot;&gt;Large Hadron Collider&lt;/a&gt; was 4.332 billion Swiss Francs. One Swiss Franc is about the equivalent of one US Dollar.&lt;/p&gt;&#xA;&lt;p&gt;Many fanciful stories about hadron colliders have been promulgated by conspiracy theorists and the ignorant.&lt;/p&gt;&#xA;&lt;p&gt;Prior to the first use of the &lt;a href=&quot;https://www.space.com/large-hadron-collider-particle-accelerator&quot; rel=&quot;nofollow noreferrer&quot;&gt;Large Hadron Collider&lt;/a&gt; in 2008 there were &lt;a href=&quot;https://www.bbc.com/future/article/20130716-will-we-ever-create-a-black-hole&quot; rel=&quot;nofollow noreferrer&quot;&gt;news reports&lt;/a&gt; that the collider would create a &lt;a href=&quot;https://science.nasa.gov/science-news/science-at-nasa/2008/10oct_lhc/&quot; rel=&quot;nofollow noreferrer&quot;&gt;black hole&lt;/a&gt; and destroy the Earth. That was about 15 years ago. The Large Hadron Collider has undertaken many experiments and the Earth has survived, intact. Nothing bad has happened to the Earth or its inhabitants, whether human or otherwise.&lt;/p&gt;&#xA;&lt;p&gt;Stories of wildlife running around in circles non-stop for 12 days or more are just rubbish! Similarly, hadron colliders do not cause earthquakes. However, they do use a lot of electricity and that's about it.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-06-25T03:12:34.357" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25322" PostTypeId="1" CreationDate="2023-06-27T04:39:31.440" Score="1" ViewCount="61" Body="&lt;p&gt;While modelling both wind waves and swell waves, whether we have to add both spectra or append wind spectra in swell spectra? Because swell spectra has high amplitude values but wind spectra has very less amplitude than swell. Kindly guide me to model both swell waves and wind waves.&lt;/p&gt;&#xA;" OwnerUserId="28085" LastActivityDate="2023-06-28T10:43:48.643" Title="Swell spectrum and wind spectrum" Tags="|oceanography|ocean-models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25323" PostTypeId="1" CreationDate="2023-06-27T06:41:10.420" Score="1" ViewCount="95" Body="&lt;p&gt;Why is wind speed generally considered at 10m above the sea surface? Is there any specific reason for this? For example, if we say wind speed is 8 m/s which implies that wind speed at a height of 10 m above the ocean surface is 8 m/s, U10 = 8 m/s. Why it is like that?&lt;/p&gt;&#xA;" OwnerUserId="28085" LastEditorUserId="2470" LastEditDate="2023-06-28T02:09:07.237" LastActivityDate="2023-06-28T02:19:04.333" Title="Wind speed at the surface of the ocean" Tags="|oceanography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25324" PostTypeId="2" ParentId="25315" CreationDate="2023-06-27T09:06:41.577" Score="2" Body="&lt;p&gt;Over recent geological history sea levels in the Arabian Gulf have fluctuated, leading to periods when sands are laid down, possibly above the shoreline, and periods when, with higher sea levels, carbonates have been deposited. The carbonates are more resistant to erosion and so form the plateau layer. The softer, weakly cemented, sandstones are more easily eroded by wind or wave and this leads to the carbonate layer being undercut. When the carbonate is unsupported it cracks and falls, but as large lumps of rock that litter the bottom of the slope. There are several papers with more detail of the coastal geology and processes in the area, &lt;a href=&quot;https://www.researchgate.net/publication/285724202_Pleistocene_carbonate_seif_dunes_and_their_role_in_the_development_of_complex_past_and_present_coastlines_of_the_UAE&quot; rel=&quot;nofollow noreferrer&quot;&gt;e.g Kirkham, 1998&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2023-06-27T09:06:41.577" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25325" PostTypeId="1" AcceptedAnswerId="25327" CreationDate="2023-06-27T14:09:08.200" Score="0" ViewCount="66" Body="&lt;p&gt;We want to move from point A to point B using a balloon.&lt;/p&gt;&#xA;&lt;p&gt;If one knows the wind directions, How can one determine the altitude that will steer the Balloon to the desired location?&lt;/p&gt;&#xA;" OwnerUserId="29172" LastEditorUserId="29172" LastEditDate="2023-07-04T11:16:00.660" LastActivityDate="2023-07-04T11:16:00.660" Title="Is there a relationship between wind direction and the bearing of travel?" Tags="|meteorology|wind|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25326" PostTypeId="2" ParentId="25323" CreationDate="2023-06-28T02:19:04.333" Score="2" Body="&lt;p&gt;The nature of the surface of oceans varies according the weather conditions and other factors. During periods of no wind seas can be calm and the surface of the water is &amp;quot;flat&amp;quot;. As wind speed increases so can the turbulence (roughness) of the surface of the water which affects things such as wave height and periodicity of waves, swells and general sea roughness.&lt;/p&gt;&#xA;&lt;p&gt;The boundary conditions of seas affects the boundary conditions of the air in contact with the sea. A calm sea has a calm air flow and a rough sea will have a rough air flow over it. With rough seas, localized wind speeds can vary, due to turbulence. The degree of air turbulence decrease with height above the sea surface. At a height of 10 m air flow is considered to be uniform and thus wind speed will also be uniform.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-06-28T02:19:04.333" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25327" PostTypeId="2" ParentId="25325" CreationDate="2023-06-28T02:43:28.450" Score="2" Body="&lt;p&gt;This is more about navigation than earth science.&lt;/p&gt;&#xA;&lt;p&gt;Wind direction will obviously affect the direction of travel of a balloon. You are unlikely to get a wind that will correspond with the bearing you require. If you do you are lucky - use it!&lt;/p&gt;&#xA;&lt;p&gt;As with sailing, you will most likely have to travel on a given bearing for a certain amount of time before changing direction for another period of time and repeat this procedure until you reach your target. With different wind speeds and directions at different altitudes this will necessitate a change of altitude to the wind direction you require for the next leg of a journey.&lt;/p&gt;&#xA;&lt;p&gt;Unless you are a very experienced balloonist, planning on-the-go to determine when to change altitude and to which altitude, will be required.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-06-28T02:43:28.450" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25328" PostTypeId="2" ParentId="25322" CreationDate="2023-06-28T10:43:48.643" Score="1" Body="&lt;p&gt;Although it is unclear which model(s) you are using, mathematically speaking:&lt;/p&gt;&#xA;&lt;p&gt;Assuming that wind sea and swell are uncorrelated, combined wind sea and swell (total sea) can be described by a double peak frequency spectrum&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ S_{total}(\omega)=S_{ws}(\omega) + S_{swell}(\omega) $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$S_{ws}(\omega)$&lt;/span&gt; is the wind sea spectrum and &lt;span class=&quot;math-container&quot;&gt;$S_{swell}(\omega)$&lt;/span&gt; is the swell spectrum.&lt;/p&gt;&#xA;&lt;p&gt;The spectral moments &lt;span class=&quot;math-container&quot;&gt;$m_{n}$&lt;/span&gt; are additive&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$m_{n,total} = m_{n,ws} + m_{n,swell}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;so e.g. combined significant wave height can be calculated as&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$H_{s,total} = \sqrt{H^{2}_{s,ws} + H^{2}_{s, swell}}$$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="18907" LastActivityDate="2023-06-28T10:43:48.643" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25329" PostTypeId="1" CreationDate="2023-06-28T13:20:35.283" Score="0" ViewCount="21" Body="&lt;p&gt;I have monthly SST data (21 years = 252 months) and now I am wondering to figure out ΔSST in python.&#xA;Basically I am unable to understand the Δ term meaning as shown in below equation:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9FX6q.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9FX6q.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I am able to calculate the first part of the equation (i.e., partial change) using statsmodel.OLS regression slope, but stuck to multiply that slope value with ΔSST.&lt;/p&gt;&#xA;" OwnerUserId="28176" LastActivityDate="2023-06-28T13:20:35.283" Title="How to calculate ΔSST change in time series climate dataset" Tags="|climate|temperature|python|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25330" PostTypeId="1" CreationDate="2023-06-28T15:43:35.167" Score="0" ViewCount="65" Body="&lt;p&gt;The coordinates of A on Mars are 125°E and 25°N. The distance of point B is x meters due east from A and y meters due north from A. How to calculate the latitude and longitude of B. Please try to use Matlan language; the coordinate point is located on Mars.&lt;/p&gt;&#xA;" OwnerUserId="29000" LastActivityDate="2023-07-12T10:09:18.940" Title="How to calculate latitude and longitude based on relative distance" Tags="|geophysics|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25332" PostTypeId="1" CreationDate="2023-06-29T00:09:58.310" Score="3" ViewCount="184" Body="&lt;p&gt;Say you are on the shore of an arbitrary lake in the world, and you want to predict its likely depth. What do you consider?&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the height of the nearby mountains&lt;/li&gt;&#xA;&lt;li&gt;the size of the lake&lt;/li&gt;&#xA;&lt;li&gt;the average distance between nearby mountain peaks&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;In terms of data, you have whatever would be readily available to a person standing at the edge of the lake.&lt;/p&gt;&#xA;&lt;p&gt;Is there a good heuristic to answer this question? Is there a good numerical model to answer this question?&lt;/p&gt;&#xA;" OwnerUserId="29182" LastActivityDate="2023-07-14T09:48:06.317" Title="How do you estimate the depth of a lake?" Tags="|water|glaciation|lakes|altitude|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25333" PostTypeId="2" ParentId="25332" CreationDate="2023-06-29T02:04:47.057" Score="3" Body="&lt;p&gt;You may as well ask if you stand on the coast of east Africa, the Arabian peninsular, Iran, west coast of India, or the southern tip of India, the west coast of Sumatra, the east coast of Madagascar, the Kerguelen Islands, the Maladives, Diego Garcia, or the west coast of Australia, how deep is the Indian Ocean?&lt;/p&gt;&#xA;&lt;p&gt;Estimating the depth of a body of water from its nearby topographical features is impossible.&lt;/p&gt;&#xA;&lt;p&gt;What distinguishes &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Baikal&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Baikal&lt;/a&gt;, in Russia, from the great lakes of North America or Lake Victoria in Africa, or the Caspian Sea? The topographical features around Lake Baikal are not extraordinary and they give no hint as to the depth of Lake Baikal; yet it has a maximum depth of 1642 m and an average depth of 744 m. It is the deepest lake in the world.&lt;/p&gt;&#xA;&lt;p&gt;What makes Lake Baikal so deep is it is a rift valley lake. The lake is associated with a rift valley that is pulling that part of the Asia apart. The same way the east African rift valley is pulling apart Africa.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Malawi&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Malawi&lt;/a&gt; (Lake Nyasa), Lake Tanganyika and Lake Turkana are all lakes in the East African Rift. As with Lake Baikal, the depth of these lakes cannot be estimated from surrounding topology or size of the lakes - length, width or area.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="22292" LastEditDate="2023-07-14T09:48:06.317" LastActivityDate="2023-07-14T09:48:06.317" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25334" PostTypeId="2" ParentId="25330" CreationDate="2023-06-29T02:58:23.340" Score="1" Body="&lt;p&gt;This question is more complicated than you might think.&lt;/p&gt;&#xA;&lt;p&gt;Are you assuming that Mars is a perfect sphere, an oblate spheroid or another type of spheroid shape.&lt;/p&gt;&#xA;&lt;p&gt;Also, even on a perfect sphere, a change of position of 1 m east or west will translate to a different change in longitude co-ordinates than a similar change of position more poleward or equatorward.&lt;/p&gt;&#xA;&lt;p&gt;On Earth 1 minute of (great circle) arc is equivalent to 1 nautical mile, which is 1.852 km, which works for latitude here. Because Mars is smaller than Earth 1 minute of arc on Mars will be a smaller distance.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="6298" LastEditDate="2023-06-30T08:51:45.257" LastActivityDate="2023-06-30T08:51:45.257" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25335" PostTypeId="1" CreationDate="2023-06-29T12:55:06.287" Score="2" ViewCount="36" Body="&lt;p&gt;I am looking for relationships between different variables in a set of MET office data. The data set is for the months May to October in 2015 and 1987 in various places in the UK. The variables measured are listed at the bottom of this post.&lt;/p&gt;&#xA;&lt;p&gt;To add some context, the data set is part of the A-level maths specification &lt;a href=&quot;https://qualifications.pearson.com/content/dam/pdf/A%20Level/Mathematics/2017/specification-and-sample-assesment/Pearson%20Edexcel%20GCE%20AS%20and%20AL%20Mathematics%20data%20set%20-%20Issue%201%20(1).xls&quot; rel=&quot;nofollow noreferrer&quot;&gt;(spreadsheet linked here)&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;I am interested in how this data set would be analysed in a meteorological setting and replicate it in a maths lesson&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;An example would be to  calculate the PMCC and perform a hypothesis test to see if it is statistically significant.&lt;/p&gt;&#xA;&lt;p&gt;For example, one linear relationship would be between sunshine and cloud cover&#xA;&lt;a href=&quot;https://i.stack.imgur.com/zVvS5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zVvS5.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I lack the knowledge to know which variables would be connected and their relationships. It would be ideal to discover linear relationships of the form:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$y= a +bx$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\log(y)=a+ b\log(x)$$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$\log(y)=a+ bx$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Variables measured in the large dataset:&lt;/p&gt;&#xA;&lt;p&gt;Daily Mean Temperature&lt;/p&gt;&#xA;&lt;p&gt;Daily Total Rainfall&lt;/p&gt;&#xA;&lt;p&gt;Daily Total Sunshine&lt;/p&gt;&#xA;&lt;p&gt;Daily Maximum Relative Humidity&lt;/p&gt;&#xA;&lt;p&gt;Daily Mean Windspeed&lt;/p&gt;&#xA;&lt;p&gt;Daily Maximum Gust&lt;/p&gt;&#xA;&lt;p&gt;Daily Mean Wind Direction&lt;/p&gt;&#xA;&lt;p&gt;Daily Maximum Gust Direction&lt;/p&gt;&#xA;&lt;p&gt;Cloud Cover&lt;/p&gt;&#xA;&lt;p&gt;Visibility&lt;/p&gt;&#xA;&lt;p&gt;Pressure&lt;/p&gt;&#xA;" OwnerUserId="29183" LastEditorUserId="29183" LastEditDate="2023-06-29T16:29:04.093" LastActivityDate="2023-06-29T16:29:04.093" Title="Linear and non linear relationship in MET office data - A-level maths" Tags="|meteorology|correlation|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25336" PostTypeId="1" CreationDate="2023-06-29T22:33:53.300" Score="10" ViewCount="2325" Body="&lt;p&gt;On a sunny day, one can find the direction (NESW) by observing the Sun's movement across the sky.&lt;/p&gt;&#xA;&lt;p&gt;In the northern hemisphere, during a clear night, one can find the direction by looking at &lt;a href=&quot;https://en.wikipedia.org/wiki/Polaris&quot; rel=&quot;nofollow noreferrer&quot;&gt;Polaris&lt;/a&gt; or other stars and constellations.&lt;/p&gt;&#xA;&lt;p&gt;However, how can one know the correct direction during a cloudy day/night without using any gadget such as a compass, the Internet, or a watch?&lt;/p&gt;&#xA;" OwnerUserId="29184" LastEditorUserId="22922" LastEditDate="2023-07-02T04:59:50.610" LastActivityDate="2023-07-04T18:33:16.393" Title="How can one know the correct direction on a cloudy day?" Tags="|earth-observation|" AnswerCount="7" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25337" PostTypeId="2" ParentId="25336" CreationDate="2023-06-30T01:28:43.180" Score="7" Body="&lt;p&gt;The first thing that can be done is to wait for sunrise of sunset. These will give the direction of east and west. Even during overcast conditions one side of the sky will be illuminated and the opposite side will be much darker.&lt;/p&gt;&#xA;&lt;p&gt;During an overcast day, one can use a tool the Vikings used, &lt;a href=&quot;https://www.researchgate.net/figure/Estimating-the-sun-position-with-two-birefringent-calcite-sunstones-under-totally_fig3_257301232&quot; rel=&quot;noreferrer&quot;&gt;sunstones&lt;/a&gt;, also known as birefringent calcite sunstones.&lt;/p&gt;&#xA;&lt;p&gt;Another method for finding north or south is to look at the trunks of old trees. Moss can sometimes grown on the side of the tree shaded from the sun. In the northern hemisphere that would be the northern side and similarly in the southern hemisphere that would be the southern side.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-06-30T01:28:43.180" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25338" PostTypeId="2" ParentId="25336" CreationDate="2023-06-30T07:39:51.807" Score="5" Body="&lt;p&gt;This requires some preparation, but if you know the weather forecast and it predicted a steady wind from a certain direction, it's easy to identify that direction.&lt;/p&gt;&#xA;" OwnerUserId="2958" LastActivityDate="2023-06-30T07:39:51.807" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25339" PostTypeId="2" ParentId="25336" CreationDate="2023-06-30T08:49:55.670" Score="15" Body="&lt;p&gt;The book &lt;em&gt;Finding Your Way Without Map or Compass&lt;/em&gt; by Harold Gatty (&lt;a href=&quot;https://www.goodreads.com/en/book/show/325485&quot; rel=&quot;nofollow noreferrer&quot;&gt;Goodreads review&lt;/a&gt;) is well worth a read if you're interested in this sort of thing.  The chapters &lt;em&gt;Reflections in the Sky&lt;/em&gt; and &lt;em&gt;Directions from the Wind&lt;/em&gt; are particularly relevant&lt;/p&gt;&#xA;&lt;p&gt;It includes more accurate ways of solar navigation, tips about moss on trees, and many others.&lt;/p&gt;&#xA;&lt;h1&gt;Wind&lt;/h1&gt;&#xA;&lt;p&gt;If you know the dominant* wind direction in open country, isolated trees will lean away from it.  This is obvious on Dartmoor (an upland area in Southern England I know well) for example. This works less well in valleys that affect the local wind direction.  In mid-latitudes the prevailing wind is usually broadly from the west, but SW is a better estimate round here.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Di5Tl.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Di5Tl.jpg&quot; alt=&quot;Lone Tree near Combestone Tor,  Dartmoor, England.   Jeffrey Pardoen, cc-by-2.0 via Wikimedia Commons&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;Lone Tree near Combestone Tor,  Dartmoor, England.     Jeffrey Pardoen, cc-by-2.0 &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Dartmoor_-_Combestone_Tor_%286238818606%29.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;via Wikimedia Commons&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;Again, using the prevailing wind, airport runways are often aligned to it - but paved ones have their direction painted on them anyway; even grass strips are likely to have some indication if they have any infrastructure at all.&lt;/p&gt;&#xA;&lt;h1&gt;Orientation to the sun&lt;/h1&gt;&#xA;&lt;p&gt;Old factory buildings (predating cheap electric lighting), where they survive, often have northlights forming a &lt;a href=&quot;https://en.wikipedia.org/wiki/Saw-tooth_roof&quot; rel=&quot;nofollow noreferrer&quot;&gt;saw-tooth roof&lt;/a&gt; (Wikipedia) - the (near-)vertical panes face away from the equator.&lt;/p&gt;&#xA;&lt;p&gt;A more modern variation on that is solar panels - they will face towards the sun.  If sited freely on the ground, they will face S in the northern hemisphere. Rooftop panels will usually face more S than N (again in the northern hemisphere) but are constrained by the roof angle.&lt;/p&gt;&#xA;&lt;p&gt;Returning to trees, many species show greater growth on the sunward side, with longer, flatter, branches&lt;/p&gt;&#xA;&lt;h1&gt;If you have a map, even a basic or mental one, but no compass&lt;/h1&gt;&#xA;&lt;p&gt;This is becoming less common as mapping is increasingly electronic, but with a map but no compass, there are things you can do.&lt;/p&gt;&#xA;&lt;p&gt;In the dark, the lights of towns reflect off the clouds, giving you the direction towards them even if they're the other side of a hill.  Or in Gatty's words:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;On land an overcast sky can signal signal many different things to the traveler. One of the simplest and most important of these things is the well-lit human city, town, airfield beacon, or even powerful lighthouse.  The loom of these lights in the sky can often be seen when their source is below the observer's horizon.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Near the coast, you can often tell which way the sea is even if you can't see it. Gatty goes into more detail, but if in one direction there are clearly no hills behind the closest few, that will mean the sea (or a plain).  Sea birds can help here too.&lt;/p&gt;&#xA;&lt;p&gt;Of course if you know where you are, and there's a distinctive peak or similar feature on the map and visible, you can orient the map to that.  In that case even a mental map and knowledge of the area can help.  I know there's a radio mast called Mendip, as the eastern end of those hills.  That's enough to get my bearings if it's within sight, combined with knowing the terrain I'm in (if it's not hidden by cloud of course). On Dartmoor I can recognise some of the hills, and know roughly how they relate to each other. There I'd have a paper map, so even if my phone battery died and I lost my compass, that would be enough for navigation if the cloudbase was above the hills.&lt;/p&gt;&#xA;&lt;p&gt;---&lt;/p&gt;&#xA;&lt;p&gt;* I originally wrote &amp;quot;prevailing wind&amp;quot;, but on re-reading Gatty this weekend I realised that was a slight error or inconsistency : he defines the &lt;em&gt;dominant wind&lt;/em&gt; in a way that takes into account the strength as well as the frequency for a direction - a weighted average, while the &lt;em&gt;prevailing wind&lt;/em&gt; only considers the frequency.  In many areas they will be similar enough to make no difference for our purposes.&lt;/p&gt;&#xA;" OwnerUserId="12280" LastEditorUserId="12280" LastEditDate="2023-07-03T10:18:15.010" LastActivityDate="2023-07-03T10:18:15.010" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25340" PostTypeId="2" ParentId="25336" CreationDate="2023-06-30T18:47:46.240" Score="4" Body="&lt;h3&gt;You don't have a compass? Build one!&lt;/h3&gt;&#xA;&lt;p&gt;This solution still requires you to have a needle though... But it's often included in first aid kits.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Put some water in a small pool, or in a cup&lt;/li&gt;&#xA;&lt;li&gt;Put a leaf in the water&lt;/li&gt;&#xA;&lt;li&gt;Rub the needle against your clothes&lt;/li&gt;&#xA;&lt;li&gt;Put the needle on the leaf&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The leaf will turn on the water until the needle's thicker end points to the north.&lt;/p&gt;&#xA;&lt;p&gt;Note that contrary to a map, a GPS, or even Polaris, this solution will give you the &lt;em&gt;magnetic north&lt;/em&gt;, not the &amp;quot;true&amp;quot; or geographic north.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2023-06-30T18:47:46.240" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25342" PostTypeId="2" ParentId="25336" CreationDate="2023-07-01T09:59:18.717" Score="2" Body="&lt;p&gt;Look for moss, mildew and algae on trees, rocks, etc.  Even houses.&lt;/p&gt;&#xA;&lt;p&gt;In the Northern Hemisphere, the Sun arcs across the southern sky.  All that sunshine on the south side of such objects reduces moisture, which is not conducive to the growth of such plants.&lt;/p&gt;&#xA;&lt;p&gt;The northern side, though, in constant shadow, retains more moisture and therefor moss, mildew, etc grows.&lt;/p&gt;&#xA;&lt;p&gt;This in only a generality, though, since for example, the north face of a mountain will have less sun anyway.&lt;/p&gt;&#xA;&lt;p&gt;It's the exact opposite in the Southern hemisphere.&lt;/p&gt;&#xA;" OwnerUserId="13675" LastActivityDate="2023-07-01T09:59:18.717" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25343" PostTypeId="2" ParentId="25336" CreationDate="2023-07-01T21:38:46.540" Score="5" Body="&lt;p&gt;In cities, I actually look for satellite dishes. They are always directed towards the equator, in Germany usually mostly South, slightly East.&lt;/p&gt;&#xA;" OwnerUserId="29190" LastActivityDate="2023-07-01T21:38:46.540" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25345" PostTypeId="2" ParentId="25336" CreationDate="2023-07-02T09:03:01.867" Score="2" Body="&lt;p&gt;big props to the other replies. this only works in some instances: If it is cloudy and there is the slightest hint of radiant direcionality, you can prod a straight stick on white piece of paper and there can be enough shade to see where the sun is.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastActivityDate="2023-07-02T09:03:01.867" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25347" PostTypeId="1" CreationDate="2023-07-03T00:40:18.853" Score="6" ViewCount="3809" Body="&lt;p&gt;If Summer Solstice around June 21 every year is the longest day of the year and closest to the sun for the Northern Hemisphere (maybe I should say receive the most direct facing sunlight), then why isn't it plus and minus 90 days around this date the hottest?  Why does it seem like it is hottest between Summer Solstice and Nov 1st?&lt;/p&gt;&#xA;&lt;p&gt;That's because we know if the summit of a evenly distributed mountain is at Spot A, then plus and minus 300 feet away from Spot A should be equally near the summit.&lt;/p&gt;&#xA;" OwnerUserId="29197" LastEditorUserId="29197" LastEditDate="2023-07-04T16:34:13.777" LastActivityDate="2023-07-04T16:34:13.777" Title="Why isn't Summer Solstice plus and minus 90 days the hottest in Northern Hemisphere?" Tags="|meteorology|seasons|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25348" PostTypeId="2" ParentId="25347" CreationDate="2023-07-03T03:08:45.827" Score="22" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;If Summer Solstice around June 21 every year is the longest day of the year and closest to the sun for the Northern Hemisphere, then why isn't it plus and minus 90 days around this date the hottest? Why does it seem like it is hottest between Summer Solstice and Nov 1st?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;First things first: Summer solstice in the Northern Hemisphere is very close to the furthest rather than closest the Earth comes to the Sun. Earth perihileon (closest distance to the Sun) is in early January and Earth aphelion (furthest distance to the Sun) is in early July. The smallish eccentricity of the Earth's orbit about the Sun plays a very minor role in the Earth's seasons. Despite the apparently contradictory nature of Earth perihelion and Earth aphelion, it is the Northern Hemisphere rather that Southern Hemisphere that experiences stronger seasons. This is primarily the result of the disparate mix of land versus ocean in the two hemispheres. The Southern Hemisphere is predominately covered by oceans while the Northern Hemisphere is closer to even (but even then, it's not quite 50-50).&lt;/p&gt;&#xA;&lt;p&gt;The key reason that June 21 is only mildly hot in the Northern Hemisphere is because the Earth's climate has &amp;quot;momentum&amp;quot;. It takes some amount of time for the increased heating in Northern Hemisphere springtime to take effect. Similarly, it takes some amount of time for the decreased heating in Northern Hemisphere autumn to take effect. August is the hottest month in many parts of the Northern Hemisphere. North Atlantic hurricanes peak in September, which is well after the June 21 solstice.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-07-03T03:08:45.827" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25349" PostTypeId="1" AcceptedAnswerId="25352" CreationDate="2023-07-03T11:25:39.643" Score="3" ViewCount="55" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;The acceleration&#xA;of glacier shrinkage after 1985 indicates a transition toward rapid down- wasting rather than a&#xA;dynamic glacier response to a changed climate&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I am unable to distinguish between downwasting and glacier response to climate change.&#xA;The above extract is from the paper by Zemp, Michael, et al. &amp;quot;Glacier fluctuations in the European Alps, 1850–2000.&amp;quot; Darkening Peaks Glacier Retreat Sci. Soc (2008).&#xA;Thank you&lt;/p&gt;&#xA;" OwnerUserId="28184" LastActivityDate="2023-07-03T19:06:25.180" Title="Difference between downwasting and dynamic glacier response to climate change" Tags="|climate-change|glaciology|glaciation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25350" PostTypeId="2" ParentId="13990" CreationDate="2023-07-03T14:30:40.073" Score="0" Body="&lt;p&gt;The oxygen that we now see as &lt;span class=&quot;math-container&quot;&gt;$\ce{O2}$&lt;/span&gt;, or at least a large part of it, likely existed primordially in rocks.&lt;/p&gt;&#xA;&lt;p&gt;When Earth differentiated its rock andviron, more was involved than just a physicsl separation of metal from rock. Under the GPa-level pressures generated by Eath's self-gravity, seemingly stable  compounds undergo changes in their chemistry. One such change of properties is &lt;a href=&quot;https://www.esrf.fr/home/news/spotlight/content-news/spotlight/spotlight248.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;iron oxides can decompose to release oxygen[1]&lt;/a&gt;, forming the iron or iron-rich materials that were then dense enough to sink beneath the mantle rock.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;[A]bove ~60 GPa, iron oxides (particularly η-Fe2O3) start to decompose, producing oxygen. Based on estimates of the amount of BIFs subducted into the Earth’s mantle, the amount of oxygen produced by the formation of Fe5O7 alone can be as high as 8 to 10 times the mass of oxygen in the modern atmosphere.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Such reactiobs continue to occur in the mantle today.&lt;/p&gt;&#xA;&lt;p&gt;The oxygen released by such reactions does not necessarily appear directly as &lt;span class=&quot;math-container&quot;&gt;$\text{O}_2$&lt;/span&gt;; it might instead formed oxygenated compounds (such as atmospheric carbon dioxide or sulfate monerals), from which elemental oxygen can eventually be extracted through organic processes.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Cited Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;E. Bykova, L. Dubrovinsky, N. Dubrovinskaia, M. Bykov, C. McCammon, S.V. Ovsyannikov, H.-P. Liermann, I. Kupenko, A.I. Chumakov, R. Rüffer, M. Hanfland, V. Prakapenka (2016). &amp;quot;Structural complexity of simple Fe2O3 oxide at high pressures and temperatures&amp;quot;. &lt;em&gt;Nature Communications&lt;/em&gt; &lt;strong&gt;7&lt;/strong&gt;, 10661; doi: 10.1038/NCOMMS10661.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2023-07-03T19:11:36.957" LastActivityDate="2023-07-03T19:11:36.957" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25352" PostTypeId="2" ParentId="25349" CreationDate="2023-07-03T19:06:25.180" Score="3" Body="&lt;p&gt;Downwasting refers to glacier thinning due to melting ice.&#xA;The statement seems to try to clarify the ambiguity that occurs when glacier changes are studied using non-stereo satellite images.&#xA;With such images, people usually link changes in area (which can be observed in the images) to changes in glacier mass (which cannot be observed in such images). However, changes in area do not necessarily mean changes in mass.&lt;/p&gt;&#xA;&lt;p&gt;For example, a warmer climate means more melt in the ablation area, but warmer air also carries more moisture, leading to an increase in snow accumulation in the upper accumulation area. Therefore, such climate change triggers a dynamic response that can reduce the area of the glacier with or without a change in glacier mass. In this example, the upper accumulation area can get thicker and the ablation area smaller. This could, in some cases, lead to a reduction in area without a reduction in mass.&lt;/p&gt;&#xA;&lt;p&gt;In that sentence, as I understand it. The author is trying to make clear that the changes observed are due to overall glacier thinning and not to a dynamic response (or mass redistribution with some areas getting thicker and others thinner).&lt;/p&gt;&#xA;&lt;p&gt;With the context given by the author, I also find the sentence a bit unclear. But is it easier to understand if you look at the original citation they give:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Paul, F. 2004. The new Swiss glacier inventory 2000:&#xA;Application of remote sensing and GIS. Ph.D.&#xA;diss., University of Zurich.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;There they say:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Although changes in glacier surface elevation cannot be measured with TM, the observed changes in glacier geometry indicate a massive down-wasting since 1985 rather than a dynamic response to a changed climate.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Where TM refers to the &amp;quot;Thematic Mapper&amp;quot; sensor onboard the old Landsat satellites.&lt;/p&gt;&#xA;" OwnerUserId="11908" LastActivityDate="2023-07-03T19:06:25.180" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25353" PostTypeId="2" ParentId="25347" CreationDate="2023-07-04T03:41:22.677" Score="9" Body="&lt;h2&gt;It's all about thermal storage/momentum.&lt;/h2&gt;&#xA;&lt;p&gt;Consider spring and fall equinox.  They should be the same temperature, right?&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;On March 20, why are the lakes still frozen?  Because the hemisphere spent the previous 6 months with the least possible solarization, and the top few feet of topsoil, groundwater, and water bodies are pretty cold.&lt;/li&gt;&#xA;&lt;li&gt;On September 23, why is it so warm?  Because the hemisphere spent the previous 6 months with the &lt;em&gt;most&lt;/em&gt; possible solarization. The planet's surface has been soaking in that heat for 6 months.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;So it's really about energy storage in the planet's surface.  You probably know if you go to a certain depth, tempertures are consistent all year - but above those depths, the heat (or lack) of prior months affects the surface and atmosphere.&lt;/p&gt;&#xA;&lt;h2&gt;You get a micro-example of this with home heating and A/C.&lt;/h2&gt;&#xA;&lt;p&gt;Half the day's solarization happens before noon. (1 PM daylight savings). So why doesn't it start getting miserably hot in the summer until 2-3 PM (and/or that's when the A/C system really starts working in earnest)?  It's our buddy thermal momentum/storage again. This time, in the structure of your house. It takes hours for solarization to warm the exterior of the house against the prior night's cooldown, and then hours for that heat to soak through insulation.&lt;/p&gt;&#xA;&lt;p&gt;Now why doesn't that A/C just run when the sun is strongest from 7 AM to 5 PM?  Because we're using ancient designs that presume fossil fuel and hydro power, and focus on comfort - aiming for 23°C/73°F at all times. Solarization accounts for the lion's share of need to run A/C, so this &lt;em&gt;time delay&lt;/em&gt; in &amp;quot;solarization vs. A/C need&amp;quot; is a huge grid management problem, called the &amp;quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Duck_curve&quot; rel=&quot;noreferrer&quot;&gt;Duck Curve&lt;/a&gt;&amp;quot;.  Smarter people would realize &lt;a href=&quot;https://www.youtube.com/watch?v=0f9GpMWdvWI&quot; rel=&quot;noreferrer&quot;&gt;the value of the thermal mass&lt;/a&gt; &lt;em&gt;inside&lt;/em&gt; the house's insulation envelope... and have the A/C run when advantageous, e.g. exactly when the sun shines.  If everyone did that, the Duck Curve &lt;em&gt;would go away&lt;/em&gt;.&lt;/p&gt;&#xA;" OwnerUserId="22545" LastActivityDate="2023-07-04T03:41:22.677" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25354" PostTypeId="1" AcceptedAnswerId="25362" CreationDate="2023-07-04T10:03:43.907" Score="2" ViewCount="706" Body="&lt;p&gt;It's commonly said that the sun sets in the west.&lt;/p&gt;&#xA;&lt;p&gt;However from my balcony I can clearly see that it sets significantly farther in the south during winter, and much farther north in the summer.&lt;/p&gt;&#xA;&lt;p&gt;Why is this? Where does it set?&lt;/p&gt;&#xA;" OwnerUserId="29210" LastActivityDate="2023-07-17T17:11:30.957" Title="Where does the sun set?" Tags="|sun|seasons|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25362" PostTypeId="2" ParentId="25354" CreationDate="2023-07-04T18:58:07.367" Score="8" Body="&lt;p&gt;Where it sets depends on 1) your latitude and 2) the Sun's &lt;a href=&quot;https://en.wikipedia.org/wiki/Declination&quot; rel=&quot;noreferrer&quot;&gt;declination&lt;/a&gt;, which varies throughout the year between -23° (December) and +23° (June). Consider the following pictures, taken from &lt;a href=&quot;http://stars.astro.illinois.edu/celsph.html&quot; rel=&quot;noreferrer&quot;&gt;A Quick Guide to the Celestial Sphere by Jim Kaler&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Objects that are on the celestial equator (like the Sun on approximately March 20th and September 23rd), rise in exactly East and set in exactly West:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KoWOR.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KoWOR.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, if during the year the Sun travels more to the southern celestial pole (denoted SCP) in the winter on the northern hemisphere, or the northern one (denoted NCP) in the summer, that circle moves, and you see the point where it crosses the horizon (corresponding to sunset and sunrise) moves to the South resp. to the North as well:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/PecTQ.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PecTQ.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2958" LastActivityDate="2023-07-04T18:58:07.367" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25363" PostTypeId="1" CreationDate="2023-07-05T06:58:31.590" Score="1" ViewCount="28" Body="&lt;p&gt;I am curious about the necessity of demean/detrend before low/high pass filter.&lt;/p&gt;&#xA;&lt;p&gt;I have seismic data which had been processed by cross correlation or other things. I want to use low pass filter for the processed data. For the raw seismic data, I know demean/detrend are needed before low-pass filter. But for the processed data which were going through demean/detrend during processing, is it still necessary to apply demean/detrend?&lt;/p&gt;&#xA;" OwnerUserId="29214" LastEditorUserId="2470" LastEditDate="2023-07-05T09:16:16.890" LastActivityDate="2023-07-05T09:16:16.890" Title="Necessity of demean/detrend before low/high pass filter" Tags="|seismology|data-analysis|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25364" PostTypeId="2" ParentId="18681" CreationDate="2023-07-05T15:42:07.877" Score="3" Body="&lt;p&gt;Since version 0.43.0 Satpy is able to read GMS-05 and GOES-09 data in VISSR archive format: &lt;a href=&quot;https://satpy.readthedocs.io/en/stable/api/satpy.readers.gms.gms5_vissr_l1b.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://satpy.readthedocs.io/en/stable/api/satpy.readers.gms.gms5_vissr_l1b.html&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13738" LastActivityDate="2023-07-05T15:42:07.877" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25365" PostTypeId="1" CreationDate="2023-07-05T16:43:29.367" Score="1" ViewCount="24" Body="&lt;p&gt;In Meteorology there is a quantity called &amp;quot;Ertel Potential Vorticity&amp;quot; &lt;span class=&quot;math-container&quot;&gt;$q_e$&lt;/span&gt; which is conserved considering isentropic flow (&lt;span class=&quot;math-container&quot;&gt;$\theta=const)$&lt;/span&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{d}{dt}\left(\frac{1}{\rho} \vec \eta \cdot \vec \nabla \theta   \right)= \frac{dq_e}{dt}=0$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Since the gradient is nearly vertical, we have&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$q_e \approx \left( \zeta_z+f\right)\cdot \left( \frac{1}{\rho}\frac{\partial \theta}{\partial z}\right)$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;So, the conserved quantity is the total vorticity times a stability factor.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, applying quasi geostrophic approximation the following conserved quantity, called &amp;quot;quasi geostrophic potential vorticity):&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$q_g = \frac{1}{f_0} \vec \nabla ^2 \phi + f + \frac{f_0}{\sigma} \frac{\partial^2 \phi}{\partial p^2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;In this case the conserved quantity is the sum of total vorticity &lt;strong&gt;plus&lt;/strong&gt; some other term, since&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\frac{1}{f_0} \vec \nabla ^2 \phi = \zeta_g$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;I wonder, how the second form &lt;span class=&quot;math-container&quot;&gt;$q_g $&lt;/span&gt;is derived as a limit of the first form &lt;span class=&quot;math-container&quot;&gt;$q_e$&lt;/span&gt;. I'm not able to transform the &lt;strong&gt;sum&lt;/strong&gt; into a &lt;strong&gt;factorized&lt;/strong&gt; form.&lt;/p&gt;&#xA;" OwnerUserId="21047" LastActivityDate="2023-07-05T16:43:29.367" Title="Comparing expressions for Ertel Potential Vorticity and Quasi Geostrophic Potential Vorticity" Tags="|meteorology|atmosphere-modelling|fluid-dynamics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25366" PostTypeId="1" CreationDate="2023-07-05T19:18:11.963" Score="3" ViewCount="57" Body="&lt;p&gt;The quasi-geostrophic &lt;span class=&quot;math-container&quot;&gt;$\omega$&lt;/span&gt;-Equation&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/4RZ22.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/4RZ22.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;is a diagnostic equation for &lt;span class=&quot;math-container&quot;&gt;$\omega$&lt;/span&gt; (=dp/dt = vertical motion) in terms of geopotential. It is derived in a few steps by manipulating vorticity and temperature equation.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, by a similar manipulation or the same two equations, we obtain the quasi-geostrophic height tendency equation for &lt;span class=&quot;math-container&quot;&gt;$\chi := \partial \Phi /\partial t $&lt;/span&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/8S40I.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8S40I.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Both equations have are related to &amp;quot;vertical motion&amp;quot; (&lt;span class=&quot;math-container&quot;&gt;$\omega, \chi$&lt;/span&gt;), are they telling more or less the same? I marvel at the amazing similarities and the subtle differences of the two terms on the right. What are the applications of both equations in particular - when to use the first, when the second?&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2023-07-06T08:11:39.860" LastActivityDate="2023-07-06T08:11:39.860" Title="What is the deeper difference between QG Omega equation and QG Height tendency equation?" Tags="|meteorology|atmosphere-modelling|fluid-dynamics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25367" PostTypeId="1" CreationDate="2023-07-05T21:41:26.350" Score="2" ViewCount="116" Body="&lt;p&gt;I am trying to figure out whether 3 particular points on Earth's surface are on the same arc (of a great circle) or not. Using Google Earth's (also ArcGIS Earth's) line tool, I see that the points are approximately on the same arc as the one in the middle is only 3 km off where the distance between the neighboring points are more than 1000 km each.&lt;/p&gt;&#xA;&lt;p&gt;Considering the oblate spheroid shape of Earth, can I confidently conclude from Google (and ArcGIS) Earth measurements that these points are not exactly on the same arc? How probable is it that approximations or some other factors cause 3 km deviation in 1000 km? Is there any method or tool that can help reaching to exact results?&lt;/p&gt;&#xA;" OwnerUserId="13672" LastEditorUserId="13672" LastEditDate="2023-07-06T07:08:32.467" LastActivityDate="2023-07-12T09:24:54.163" Title="How to find out if three points on Earth are on the same great circle arc?" Tags="|mapping|gis|geodesy|coordinate-system|projection|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25368" PostTypeId="1" CreationDate="2023-07-06T01:08:56.810" Score="1" ViewCount="65" Body="&lt;p&gt;The news is reporting a global climate event:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The &lt;strong&gt;hottest day ever on Earth since records began&lt;/strong&gt; happened on July 3, 2023.&lt;br /&gt;&#xA;&lt;sub&gt;&lt;a href=&quot;https://www.nbcdfw.com/weather/weather-connection/earths-hottest-day-ever-was-recorded-on-july-3-2023/3289861/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth's hottest day ever recorded was on July 3, 2023&lt;/a&gt;&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Turns out, the record was broken again July 4:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zIDZi.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zIDZi.png&quot; alt=&quot;image showing &amp;quot;2m Temperature World&amp;quot; from 1979 to July 4, 2023&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;sub&gt;&lt;a href=&quot;https://climatereanalyzer.org/clim/t2_daily/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate Reanalyzer&lt;/a&gt;, University of Maine.&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The above website gives the description:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This page provides &lt;strong&gt;time series&lt;/strong&gt; and &lt;strong&gt;map&lt;/strong&gt; visualizations of daily mean &lt;strong&gt;2-meter air temperature&lt;/strong&gt; from the NCEP Climate Forecast System (CFS) version 2 (April 2011 – present) and CFS Reanalysis (January 1979 – March 2011). CFS/CFSR is a numerical climate/weather modeling framework that ingests surface, radiosonde, and satellite observations to estimate the state of the atmosphere at hourly time resolution onward from 1 January 1979. The horizontal gridcell resolution is 0.5°x0.5° (~ 55km at 45°N). Temperature anomalies are in reference to 1979–2000 climatology for each specific day of the year.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;strong&gt;time series chart&lt;/strong&gt; displays area-weighted means for the selected domain. For example, if World is selected, then each daily temperature value on the chart represents the average of all gridcells 90°S–90°N, 0–360°E and accounts for the convergence of longitudes at the poles. ...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Alright, so it's averaged over selected points around the globe.  But...&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question&lt;/strong&gt;: How is the &amp;quot;hottest day ever on Earth&amp;quot; determined?&lt;/p&gt;&#xA;&lt;p&gt;There are two issues here:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&amp;quot;day&amp;quot; is not defined in the same way across the globe, and when it's daytime (and thus hot) in one place, it's simultaneously not daytime in another place; and&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;I don't see a reason why the northern hemisphere's summer is hotter on a global plot than the southern hemisphere's summer.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="18754" LastEditorUserId="18754" LastEditDate="2023-07-06T01:17:50.600" LastActivityDate="2023-07-06T01:17:50.600" Title="How is the &quot;hottest day ever on Earth&quot; determined?" Tags="|climate-change|climate|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25369" PostTypeId="1" CreationDate="2023-07-06T09:29:58.113" Score="3" ViewCount="118" Body="&lt;p&gt;I know subduction in plate tectonics is mainly density driven.&lt;/p&gt;&#xA;&lt;p&gt;Probably a hypothetical question, but can weaknesses caused by tidal forces have an influence on the start of a subduction zone? Would this have been more likely in earlier earth history when the Moon's tidal forces where much stronger due to it having been closer?&lt;/p&gt;&#xA;" OwnerDisplayName="user29219" LastEditorUserId="2470" LastEditDate="2023-07-06T19:30:23.003" LastActivityDate="2024-01-18T16:06:55.800" Title="Do tidal forces affect subduction?" Tags="|plate-tectonics|tides|subduction|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25370" PostTypeId="1" CreationDate="2023-07-06T10:34:10.647" Score="0" ViewCount="14" Body="&lt;p&gt;I have an (maybe not so clever) idea to apply the shallow water model for computing the year-round watershed runoff of a catchment. It means using of real topography with variable slopes and roughness, length of the real time period about 31536000 seconds, real precipitation, temperature, snow cover and other data, etc. I read some books and papers about hydrodynamic models and many, many numerical methods for solving them. Shallow water model is usually applied for oceanic circulation, tides and estuaries, flood waves with relatively short time duration, etc. There are plenty of methods, described in the literature, like explicit and implicit ones, finite difference, finite volume, finite element, and so on. Every class of methods has its own pros and cons. There are also different flow regimes, different types of initial and boundary conditions, different conditions of the flow over the bottom, for example wet/dry conditions, etc. Not to mention some other processes and models like infiltration and porous media model which are also natural (but at the beginning only the shallow water model is important).&lt;/p&gt;&#xA;&lt;p&gt;So, the questions are:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Is this idea even applicable and doable (this is especially about year-round duration of the time period)?&lt;/li&gt;&#xA;&lt;li&gt;Which numerical methods are simple and stable, for starting the project, solving the shallow water model, and obtaining reasonable results at the beginning (which means positive water height, oscillations as small as possible, etc.)?&lt;/li&gt;&#xA;&lt;li&gt;Which numerical methods are not so simple but yet stable, for advanced modelling, and obtaining better results with the shallow water model?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;I appreciate every comment, suggestion, and advise.&lt;/p&gt;&#xA;" OwnerUserId="29220" LastActivityDate="2023-07-06T10:34:10.647" Title="Shallow water model for year-round watershed runoff" Tags="|numerical-modelling|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25371" PostTypeId="1" CreationDate="2023-07-07T08:07:01.220" Score="0" ViewCount="21" Body="&lt;p&gt;For an accurate flood forecast, up to what height maximum from the ground level one can put the &lt;a href=&quot;https://en.wikipedia.org/wiki/Rain_gauge#Tipping_bucket_rain_gauge&quot; rel=&quot;nofollow noreferrer&quot;&gt;TBRG&lt;/a&gt; without any obstacles and still receive accurate rainfall?&lt;/p&gt;&#xA;" OwnerUserId="29225" LastEditorUserId="6298" LastEditDate="2023-07-07T22:21:52.520" LastActivityDate="2023-07-07T22:21:52.520" Title="Accurate Rainfall with TBRG" Tags="|meteorology|weather-forecasting|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25372" PostTypeId="1" AcceptedAnswerId="25374" CreationDate="2023-07-07T08:48:37.947" Score="1" ViewCount="36" Body="&lt;p&gt;It's a wind map from the ICON (13km grid) model of the Atlantique ocean of this 7 July 2023. I get that there's two depression near each other interacting but how there's only a very thin line as the resulte of the interaction ? If it's not an artifact from the model, why is it SO thin and not align with the center of these depression ?&lt;/p&gt;&#xA;&lt;p&gt;I've also checked with other models (NEMS (4km) and UKV (2km)) and it's the same thing...&lt;/p&gt;&#xA;&lt;p&gt;Just so you know, I'm an engineering student, so it's not my main stuff by I'm still interested by the subject !&#xA;&lt;a href=&quot;https://i.stack.imgur.com/zaiPo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zaiPo.png&quot; alt=&quot;Strange thing the wind is doing in the Atlantic ocean&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29226" LastActivityDate="2023-07-07T09:17:56.017" Title="Wind wall of depression" Tags="|wind|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25373" PostTypeId="2" ParentId="25371" CreationDate="2023-07-07T09:10:56.963" Score="1" Body="&lt;p&gt;The top of all &lt;a href=&quot;http://www.bom.gov.au/climate/cdo/about/rain-measure.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;rain gauges&lt;/a&gt; need to be 30 cm above the ground. The lateral placement of all rain gauges is a distance that is twice the height of the nearer tallest item (tree, building, fence, etc.).&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-07-07T09:10:56.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25374" PostTypeId="2" ParentId="25372" CreationDate="2023-07-07T09:17:56.017" Score="1" Body="&lt;p&gt;From the synoptic chart from the UK Met Office, the thin line in your picture corresponds to a frontal system. Immediately to the west of Ireland there is a cold front (blue line with triangles) and to the southwest of that, and inline with that, is a warm front (red line with semicircles).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hZh4x.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hZh4x.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-07-07T09:17:56.017" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25375" PostTypeId="1" CreationDate="2023-07-07T17:07:03.287" Score="2" ViewCount="29" Body="&lt;p&gt;the closest i've got was with a table in the following manual that only went up to the year 2000.&#xA;&lt;a href=&quot;https://tidesandcurrents.noaa.gov/publications/SpecialPubNo98.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://tidesandcurrents.noaa.gov/publications/SpecialPubNo98.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29230" LastActivityDate="2023-07-07T17:07:03.287" Title="were can I find the Greenwich equilibrium argument for tidal prediction(Vo+u)?" Tags="|tides|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25376" PostTypeId="1" AcceptedAnswerId="25401" CreationDate="2023-07-08T04:40:12.387" Score="1" ViewCount="99" Body="&lt;p&gt;A well-known intercontinental country (a country that exists in two or more continents) is Egypt.&lt;/p&gt;&#xA;&lt;p&gt;It has been divided to two parts by the man-made Suez Canal. The Sinai peninsula which is at the east side of the Canal is contiguous with Asia, and the rest of the country is contiguous with Africa.&lt;/p&gt;&#xA;&lt;p&gt;Also, in the case of Panama there is a man-made canal (Panama Canal) which divides the country to two parts. The eastern part is contiguous with South America and the western part is contiguous with North America.&lt;/p&gt;&#xA;&lt;p&gt;So why isn't Panama considered an intercontinental country like Egypt is?&lt;/p&gt;&#xA;" OwnerUserId="29082" LastEditorUserId="29082" LastEditDate="2023-07-08T04:48:55.540" LastActivityDate="2023-07-13T21:15:53.070" Title="Why isn't Panama considered an intercontinental country?" Tags="|geography|continent|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25377" PostTypeId="1" CreationDate="2023-07-09T11:59:00.797" Score="1" ViewCount="39" Body="&lt;p&gt;The hottest and coldest days of the year lag the solstices by several weeks.  Where is the latent heat stored that causes that?  Obviously, it's some combination of land, sea, and air, but which (if any) is predominant?&lt;/p&gt;&#xA;&lt;p&gt;[Update] I guess this is a bad question, in that it's based on the parochial assumption that this seasonal lag is universal.  It's not - see &lt;a href=&quot;https://earthscience.stackexchange.com/questions/3193/how-can-the-average-coldest-day-of-the-year-be-before-the-winter-solstice&quot;&gt;How can the average coldest day of the year be before the winter solstice?&lt;/a&gt;.  I'll close this in a couple of days.&lt;/p&gt;&#xA;" OwnerUserId="640" LastEditorUserId="640" LastEditDate="2023-07-09T17:28:51.050" LastActivityDate="2023-07-09T17:28:51.050" Title="Where is seasonally latent heat stored?" Tags="|climate|temperature|seasons|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25378" PostTypeId="2" ParentId="25376" CreationDate="2023-07-09T17:36:19.477" Score="2" Body="&lt;p&gt;The boundary between North and South America is usually considered to be at (or very close to) the Colombia-Panama border.  See e.g., conflictingly, &lt;a href=&quot;https://en.wikipedia.org/wiki/Boundaries_between_the_continents#Mainland_2&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia on continent boundaries&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="640" LastActivityDate="2023-07-09T17:36:19.477" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25379" PostTypeId="1" CreationDate="2023-07-10T05:48:24.820" Score="1" ViewCount="33" Body="&lt;p&gt;I'm looking to create a map of the U.S. that depicts mean winter and summer temperatures. Is there a software suitable for this?&lt;/p&gt;&#xA;&lt;p&gt;I found CSVs of data here: &lt;a href=&quot;https://www.ncei.noaa.gov/data/normals-daily/2006-2020/access/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncei.noaa.gov/data/normals-daily/2006-2020/access/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But it is not easy to understand the format, or to plot it.&lt;/p&gt;&#xA;" OwnerUserId="29242" LastActivityDate="2023-07-10T05:48:24.820" Title="Temperature Data Software" Tags="|climate-change|climate|temperature|mapping|climate-data|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25380" PostTypeId="1" CreationDate="2023-07-10T07:39:45.840" Score="4" ViewCount="48" Body="&lt;p&gt;In Jonathan Martin's Book &amp;quot;Mid-Latitude Atmospheric Dynamics&amp;quot; there is a chapter about PV anomalies. As an example, a positive PV anomaly is discussed.&lt;a href=&quot;https://i.stack.imgur.com/fpBxc.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fpBxc.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;What is the reason, that high PV is advected from the north at the west and low PV is advected from the south at the east of the anomaly in the figure? I cannot follow the argumentation here: Is it because there is generally higher PV in the north near the tropopause?&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2023-07-11T05:50:55.860" LastActivityDate="2023-07-11T05:50:55.860" Title="Why positive PV Anomaly moves westwards?" Tags="|meteorology|atmosphere-modelling|vorticity|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25381" PostTypeId="1" CreationDate="2023-07-10T14:12:14.183" Score="0" ViewCount="18" Body="&lt;p&gt;I'm interested in knowing about &lt;a href=&quot;https://en.wikipedia.org/wiki/Sa%C3%B4ne&quot; rel=&quot;nofollow noreferrer&quot;&gt;Saône River&lt;/a&gt; sand found at the river's headwater just outside the city of Dijon, France, as seen in the image below, Saône highlighted red, Dijon highlighted yellow. (This would be the sand found along the riverbank).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/tb2e3l.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tb2e3l.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Referring to the figure below, what is known (or thought) about the sphericity and roundness of the Saône sand near Dijon? I.e., what value for sphericity (y-axis) and roundness (x-axis) characterizes the sand?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KwP5d.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KwP5d.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Can anyone provide a picture of the sand?&lt;/p&gt;&#xA;" OwnerUserId="538" LastActivityDate="2023-07-10T14:12:14.183" Title="What is the sphericity and roundness of Saône River Sand" Tags="|sedimentology|rivers|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25383" PostTypeId="2" ParentId="8364" CreationDate="2023-07-10T19:50:00.963" Score="2" Body="&lt;p&gt;I found this while looking for something else (a Larry Niven story, with the condemnation of Mars as being &amp;quot;useless, at the bottom of a hole&amp;quot;), but meh.&lt;/p&gt;&#xA;&lt;p&gt;Elsewhere I'd collated a number of equations relating height and atmospheric pressure. It's not the simplest of topics, which is why I made a pile of notes then forgot the gory details. But tweaking my collection of models for a 35km (below sea level, not below ground level ; if you'd done geological work at the shore of the Caspian Sea and altitude -23m, you too would have got fed up with debugging other people's software over this point) deep borehole. My collection gives bottom-hole pressures of 2,095,904.36 ; 1,529,809.85 and 6,098,523.97 Pa, or 20, 15 and 61 atmospheres. Considerable variation.&lt;/p&gt;&#xA;&lt;p&gt;From SCUBA training, any of those pressures would rapidly induce rapidly lethal oxygen toxicity if exposed to &amp;quot;air&amp;quot; at that pressure. The pressure itself is in the realm of &amp;quot;saturation diving&amp;quot;, where you'd take several days to &amp;quot;descend&amp;quot; (in a pressure chamber) to that depth, and simultaneously change your breathing gas to one dominated by helium (or even hydrogen - really scary stuff!). Coming back &amp;quot;up&amp;quot;, to surface, you'd take a week or two, on steadily changing gas mixtures.&lt;/p&gt;&#xA;&lt;p&gt;As a geologist, your wallrock temperatures could easily vary by a factor of &amp;quot;several&amp;quot;, from an upper range approaching 1000 K to low ranges of 500 or 600 K. The bottom ranges might, briefly, be survivable by unprotected human meat. Long enough that the oxygen poisoning would get you before you died of hyperthermia. But you wouldn't last long, and would come back up approximating &amp;quot;bil tong&amp;quot; or &amp;quot;jerkey&amp;quot;. Filling your descent suit with barbecue sauce and adding ... &amp;quot;plumbing&amp;quot; might be considerate for people who want to grok your fullness.&lt;/p&gt;&#xA;&lt;p&gt;My &amp;quot;Atmospheric Pressure&amp;quot; notes refers to Wiki (no article name), and &amp;quot;https://agupubs.pericles-prod.literatumonline.com/doi/10.1029/2002JA009430&amp;quot; but I honestly can't remember the gory details. That's what notes are for.&lt;/p&gt;&#xA;" OwnerUserId="29247" LastActivityDate="2023-07-10T19:50:00.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25385" PostTypeId="2" ParentId="22393" CreationDate="2023-07-12T09:03:51.840" Score="0" Body="&lt;p&gt;The West coast of Greenland facing onto the Davis Straight would probably be your best approximation today. Note that although there are extensive glaciers reaching the sea, the Eskimos can move around in the area with a degree of facility, living mostly on marine resources.&#xA;Don't forget that at glacial maximum, sea level was around 100m lower, so you'd need to adjust your mapping/ modelling to that different sea level.&lt;/p&gt;&#xA;" OwnerUserId="29247" LastActivityDate="2023-07-12T09:03:51.840" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25386" PostTypeId="2" ParentId="25369" CreationDate="2023-07-12T09:11:23.907" Score="0" Body="&lt;p&gt;My gut feeling would be, &amp;quot;no&amp;quot;. Not because the forces are too small, but because they reverse with such a high frequency.&#xA;People have been looking in databases of earthquakes and volcanic activity for decades for periodicities like this, because it seems reasonable to expect the state of the tide (position of the Moon) to have an effect. TTBOMK, any signals that have been reported are at quite low significance, and are disputed.&lt;/p&gt;&#xA;&lt;p&gt;There's a philosophical challenge too. Does a subduction zone have a beginning in time that is meaningful at the &amp;quot;month&amp;quot; level? Except during aftershock swarms, it's not normal to get multiple major earthquakes in a month on a modest length of a subduction zone.&lt;/p&gt;&#xA;" OwnerUserId="29247" LastActivityDate="2023-07-12T09:11:23.907" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25387" PostTypeId="2" ParentId="25367" CreationDate="2023-07-12T09:24:54.163" Score="1" Body="&lt;p&gt;I would take the same approach as Jean-Marie Prival, but using a different toolset, because I'm not familiar with GIS in general and have never been in a room that has ever seen Mathematica. But I do have, and have used a few times, a collection of aviation-relevant algorithms, which includes a tool that will take two Lat-Long pairs and give you the great circle course between them. For the (putative arc A-B-C, if the direction from A-&amp;gt;B is the same as from A-&amp;gt;C, then you're on the same great circle. (I'd double-check by comparing C-&amp;gt;A and C-&amp;gt;B, because I know I'm at the limits of my geometry.)&lt;/p&gt;&#xA;&lt;p&gt;In practical surveying - steering oil wells to hit each other, or to avoid hitting each other, treating the Earth as a simple oblate spheroid is sufficient ; you don't need to go around adding in the second and higher orders of difference from a sphere. Whether your survey tool is sitting exactly axially in your drilling string (or is centralised in the borehole  if surveying on wireline) is more significant, and has cause more blowouts (that I've heard of).&lt;/p&gt;&#xA;" OwnerUserId="29247" LastActivityDate="2023-07-12T09:24:54.163" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25388" PostTypeId="2" ParentId="25354" CreationDate="2023-07-12T09:32:40.137" Score="-1" Body="&lt;p&gt;I tried working this out myself years ago. Back in the days of dialup to a Compuserve local node, before they had an internet interface. But it was also the other side of a visit from the burglars, who thought the rack of &amp;quot;gold&amp;quot; CDs must be worth stealing too, and that was my backup.&lt;/p&gt;&#xA;&lt;p&gt;It's a common &amp;quot;problem&amp;quot; in celestial mechanics, and I recall the solution involving the square of the cosine of the observatory's latitude, as well as, obviously, the date. But I'd have to re-create 30 .... 26 year old notes from a college course to go any more detail. That course, and the college that did &amp;quot;Navigation by Sextant&amp;quot; as a compulsory course for sailors wanting to get their &amp;quot;Master&amp;quot; certificate are long since bulldozed. Along with the observatory.&lt;/p&gt;&#xA;" OwnerUserId="29247" LastActivityDate="2023-07-12T09:32:40.137" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25389" PostTypeId="2" ParentId="13990" CreationDate="2023-07-12T09:50:27.307" Score="1" Body="&lt;p&gt;Someone (I've lost track of whom. Tl;dr.) is seriously underestimating the amount of reduced carbon in sediments.&lt;/p&gt;&#xA;&lt;p&gt;Having examined (and logged, and submitted to oil companies and government, hundreds of thousands of descriptions of drill cuttings, I'd estimate (very crudely) the proportion of elemental carbon in fine-grained sediments (&amp;quot;mudrocks&amp;quot; if you work for BP ; &amp;quot;silt and shale&amp;quot; for the rest of the world)  at around 1%. That's of the total rock volume. Wherever you look in mudrocks, you see myriads of tiny (silt and finer grade) flakes of black elemental carbon. Some of them are palynomorphs (a whole industry in itself), but most are amorphous carbon to poorly crystalline graphite.&lt;/p&gt;&#xA;&lt;p&gt;Once carbon gets to graphite near the Earth's surface, it tends to stay there unless it gets finely dispersed in a wildfire - which is going to be generating charred organic matter of it's own.&lt;/p&gt;&#xA;&lt;p&gt;I don't see any problem with the Earth's atmosphere depositing around 1m total thickness of carbon dust over the approx 3 Gyr since the GOE started.&lt;/p&gt;&#xA;&lt;p&gt;Now, doing the same to terraform Venus ... that's going to produce about 90m of carbon dust on the surface. Still less of a challenge than making an atmosphere for Mars.&lt;/p&gt;&#xA;" OwnerUserId="29247" LastActivityDate="2023-07-12T09:50:27.307" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25390" PostTypeId="1" CreationDate="2023-07-12T09:58:27.420" Score="0" ViewCount="11" Body="&lt;p&gt;Whether swell and wind waves have same wind direction or it may have different wind direction?&#xA;what is the wave number range of swell waves and wind waves. Thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="28085" LastActivityDate="2023-07-12T09:58:27.420" Title="Wind direction and wave number of swell and wind waves" Tags="|oceanography|ocean-models|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25391" PostTypeId="2" ParentId="25330" CreationDate="2023-07-12T10:09:18.940" Score="1" Body="&lt;p&gt;It's clearly a homework question, so I'm going to answer it in the style of a &amp;quot;marking scheme&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;The answer needs to state somewhere &amp;quot;The radius of Mars is &amp;quot; and give a value, with units of metres. Units must be stated explicitly.&lt;/p&gt;&#xA;&lt;p&gt;The answer needs to calculate the length in degrees of arc (or minutes, or seconds, or radians, but STATE UNITS) of 1 m on the ground on the N-S great circle. It needs to be stated as being a GREAT circle.&lt;/p&gt;&#xA;&lt;p&gt;The answer needs to calculate the length in degrees of arc (etc) of 1 m on the ground along a SMALL circle 25 degrees from the equator (which is a GREAT circle). That it's a small circle must be stated.&lt;/p&gt;&#xA;&lt;p&gt;Given those factors, develop by simple arithmetic an expression for the Lat/Long of the new point in terms of the lengths X and Y of the ground displacements, and the Lat/Long of the original point.&lt;/p&gt;&#xA;&lt;p&gt;I think that covers it. I reckon there should be about 12 points for a perfect answer, with 4 of them being for the final expression.&lt;/p&gt;&#xA;&lt;p&gt;===&lt;/p&gt;&#xA;&lt;p&gt;I hated the bullies at school who would beat the answers to the homework out of me. So I'd give them solutions which were wrong &lt;em&gt;in an interesting way&lt;/em&gt;, so they had to explain &amp;quot;their&amp;quot; error to the whole class. Revenge is a dish best served at absolute zero. I'd get another beating, but it was worth it to see them squirm.&lt;/p&gt;&#xA;" OwnerUserId="29247" LastActivityDate="2023-07-12T10:09:18.940" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25392" PostTypeId="2" ParentId="25332" CreationDate="2023-07-12T10:23:43.197" Score="1" Body="&lt;p&gt;IF (a big if) you can see enough local topography to estimate the underwater slopes, you can get some likely bounds. If the lake had filled yesterday, projecting the slopes on either side until they meet will give you an estimate for the lake depth. But the lake is almost certain to be shallower than this, because sediment would have been accumulating for (however long the lake has been around.&lt;/p&gt;&#xA;&lt;p&gt;That's a defensible algorithm around here, where the landscape was covered by ice a few millennia ago, and lakes have been filling since the landscape was gouged more-or-less clean.&lt;/p&gt;&#xA;&lt;p&gt;But Fred's point about tectonically controlled lakes is very true - if the lake has been around for long enough for fault movement to have a significant effect, all bets are off.&lt;/p&gt;&#xA;&lt;p&gt;I'll add the extremely deep and highly lethal volcanic maar lakes of Cameroon to the list of &amp;quot;won't work here&amp;quot; situations.&lt;/p&gt;&#xA;&lt;p&gt;And my local Loch Ness, even if tectonically almost inactive, is extremely overdeepened compared to it's surrounding topography.&lt;/p&gt;&#xA;&lt;p&gt;And Loch Tay has three significantly different underwater topographies along it's length ...&lt;/p&gt;&#xA;&lt;p&gt;In the simplest of cases, you can make an educated guess. While you're loading the reels of rope and a heavy &amp;quot;sinker&amp;quot; onto your boat to go measure. Remember that detecting &amp;quot;bottom&amp;quot; can itself be a tricky question.&lt;/p&gt;&#xA;" OwnerUserId="29247" LastActivityDate="2023-07-12T10:23:43.197" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25393" PostTypeId="2" ParentId="25315" CreationDate="2023-07-12T10:38:17.100" Score="0" Body="&lt;p&gt;I got to about the same idea as Andy M, but weighing the photo evidence slightly differently.&lt;/p&gt;&#xA;&lt;p&gt;In the main, off-white, section of the exposed face, you can't see any of the the brown, resistant stones. But something similar is visible near the top of the cliff.&lt;/p&gt;&#xA;&lt;p&gt;Note that the cliff has colour and texture banding parallel to the land surface (before the recent erosion). The band of source material is also parallel to the ground surface.&lt;/p&gt;&#xA;&lt;p&gt;That looks like the development of a soil structure (in layers, parallel to the ground surface) and in particular a CALCRETE soil where (as Andy M says) carbonate minerals precipitate in the soil to form a hard band. This hard band is then protecting the softer material below from erosion until the hard carbonate blocks topple from the edge of the cliff. The soft material beneath is then rapidly washed away.&lt;/p&gt;&#xA;&lt;p&gt;The formation of calcrete soils in historical time in the Middle East, particularly in Mesopotamia, has seriously damaged agricultural productivity since the region was the centre of the &amp;quot;Fertile Crescent&amp;quot;. Abu Dhabi is a little distant from this classical (in several senses) example of man wrecking the topsoil he depends on, but has a similar climate.&lt;/p&gt;&#xA;&lt;p&gt;I remember the Monsoon arriving in Abu Dhabi, while working on a rig there. It went from 38° C and 10% humidity to 35° C and 90% humidity. In one day. Horrible!&lt;/p&gt;&#xA;" OwnerUserId="29247" LastActivityDate="2023-07-12T10:38:17.100" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25394" PostTypeId="2" ParentId="25314" CreationDate="2023-07-12T10:54:55.510" Score="1" Body="&lt;p&gt;Fred has it wrong for the right reason.&lt;/p&gt;&#xA;&lt;p&gt;The rope has weight (or if you follow @jpa, negative weight), so you want to detect the difference between (weight of rope) + (weight of sinker) and (weight of rope).&lt;/p&gt;&#xA;&lt;p&gt;In which case, you want as light a &amp;quot;rope&amp;quot; as possible, and as heavy a sinker. You probably also want some moderately accurate load indicator on your winch - running it over a pulley suspended on a suitably stiff spring would do, or you can get more sophisticated.&lt;/p&gt;&#xA;&lt;p&gt;@JPA's buoyant rope will eventually suspend the weight of the sinker and leave a pool of rope on the sea's surface.&lt;/p&gt;&#xA;&lt;p&gt;When the Challenger did the first oceanographic survey, I think they used &amp;quot;piano wire&amp;quot; (single strand, high-tensile steel) because they were routinely sounding in 5km of water.&lt;/p&gt;&#xA;&lt;p&gt;@RBarryYoung (Beanpole Barry, of &amp;quot;&amp;amp; Dr Toxic&amp;quot; fame ? ) - there is archaeological evidence of twisted fibre  ... well back into the Neolithic. Pierced bead decorations imply either a cord for stringing them or thread for sewing the beads onto clothes.&lt;/p&gt;&#xA;&lt;p&gt;Actually ... there are pierced ostrich shell fragments in the South African deposits ... not Bloombos Cave (of the grooved ochre), but nearby. It was in Nature a few years ago. Sorry, details not in mind, but a hundred thousand years ago if not more.&lt;/p&gt;&#xA;" OwnerUserId="29247" LastActivityDate="2023-07-12T10:54:55.510" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25395" PostTypeId="2" ParentId="25229" CreationDate="2023-07-12T11:47:16.943" Score="2" Body="&lt;p&gt;You seem to think that the Earth's magnetic field should be, in some sense, smooth?&lt;/p&gt;&#xA;&lt;p&gt;It's not.&lt;/p&gt;&#xA;&lt;p&gt;It approximates to a solenoid field. But it's not generated by electrical currents moving in a solenoid. It's (probably) generated by convection currents driven by density moving conducting fluids through an existing magnetic field (itself generated by the movement of the adjacent cells of the core).&lt;/p&gt;&#xA;&lt;p&gt;It may be helpful to consider the magnetic fields of Uranus and Neptune. They too are &amp;quot;approximately&amp;quot; solenoidal, and are probably formed by the same process as in Earth (but different materials). But the pseudo-solenoidal field of Uranus is inclined at ~59° to the rotation axis (compared to Earth's ~20°) and is &amp;quot;centred&amp;quot; 1/3 of the way from the core to the south pole. It's no where near symmetrical to the planet. Neptune is worse - it's magnetic &amp;quot;centre&amp;quot; is over half-way from the core to the surface, and not anywhere near the rotation axis. And it's inclined at ~47° to the rotation axis that it's not on.&lt;/p&gt;&#xA;&lt;p&gt;Compared to those, Earth's field is reasonably well behaved. The biggest (and most variable, within human lifetimes) anomaly is the &amp;quot;South Atlantic Anomaly&amp;quot;, which &lt;em&gt;may&lt;/em&gt; indicate the location of a rising plume in the core. But that's far from agreed.&lt;/p&gt;&#xA;" OwnerUserId="29247" LastActivityDate="2023-07-12T11:47:16.943" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25396" PostTypeId="1" AcceptedAnswerId="25397" CreationDate="2023-07-12T19:21:26.050" Score="1" ViewCount="103" Body="&lt;p&gt;On 22 June 2023 in my village in LE8, south Leicester, UK, there was a large deluge of rain and my house got lightly flooded - the only time ever in 30 years. I'm trying to make a claim now; the insurers have gone on the internet and looked at the weather for that date for Leicester via timeanddate.com, worldweatheronline, etc. They say there wasn't enough rain on that date to have caused flooding in a structurally sound building - which they do, only 2.2mm max I've seen.&lt;/p&gt;&#xA;&lt;p&gt;Why is this? Looking at meteo centre, we're kind of in the middle of an empty spot for professional weather stations. Could this be why? Are professional weather stations the only places to record weather? So when I look up our postcode in south Leicester historical weather on timeanddate or similar, is it just interpolating between adjacent weather stations?&lt;/p&gt;&#xA;&lt;p&gt;Will a city like Leicester have a weather recording device, or is it only in these fairly infrequent weather stations that it is officially recorded?&lt;/p&gt;&#xA;&lt;p&gt;Also, the met office seems to have data for the past 48 hrs, but for no longer than this (excepting special weather events) - why do they only show 48hrs worth?&lt;/p&gt;&#xA;" OwnerUserId="29257" LastEditorUserId="2470" LastEditDate="2023-07-13T00:28:19.827" LastActivityDate="2023-08-22T07:15:42.957" Title="Weather record last month in the UK" Tags="|meteorology|weather-forecasting|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25397" PostTypeId="2" ParentId="25396" CreationDate="2023-07-13T01:19:07.147" Score="2" Body="&lt;p&gt;To begin with, rainfall is not always uniform. Within any rainfall event there can be localized anomalies with lesser or greater amounts of rainfall, including deluge type events. In addition to looking at recorded rainfall data you should look for &lt;a href=&quot;https://www.metoffice.gov.uk/weather/maps-and-charts/rainfall-radar-forecast-map#?model=ukmo-ukv&amp;amp;layer=rainfall-rate&amp;amp;bbox=%5B%5B51.88583130730151,-3.4717675888511588%5D,%5B52.9296173475589,0.18942625880509215%5D%5D&quot; rel=&quot;nofollow noreferrer&quot;&gt;rain radar&lt;/a&gt; data. Such data is usually presented as a video with color coded moving images of rainfall intensity for a particular region during a given time period.&lt;/p&gt;&#xA;&lt;p&gt;The location of weather stations in the UK will be determined by the Met Office.&lt;/p&gt;&#xA;&lt;p&gt;Given the size of Leicester, it seems unusual that the &lt;a href=&quot;https://www.metoffice.gov.uk/weather/observations/gcr5qn5jy&quot; rel=&quot;nofollow noreferrer&quot;&gt;UK Met Office&lt;/a&gt; does not have at least one rain gauge or weather observation station in Leicester.&lt;/p&gt;&#xA;&lt;p&gt;Regarding the Met Office apparently only having data of 48 hours. It might only display such data online for 48 hours but it maintains all weather observation data within its database. You might have to pay to obtain the data for the date in question.&lt;/p&gt;&#xA;&lt;p&gt;Aviation can be greatly affected by weather, it is not unusual for weather stations to be located at airports. There may be a weather station at &lt;a href=&quot;https://en.wikipedia.org/wiki/Leicester_Airport&quot; rel=&quot;nofollow noreferrer&quot;&gt;Leicester Airport&lt;/a&gt;, for which you could obtain data. The caveat that I'll apply to this is as I stated in my first paragraph, weather can be highly variable and the rainfall event you claimed occurred at your house may not have occurred at the airport, or elsewhere.&lt;/p&gt;&#xA;&lt;p&gt;I would advise getting the rain radar data for that day, prior to and just after the time of the rainfall event in question.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-07-13T01:19:07.147" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25398" PostTypeId="1" CreationDate="2023-07-13T18:20:35.130" Score="-3" ViewCount="105" Body="&lt;p&gt;ok so iron came from asteroids that fell down on earth. but why do human body has iron if its not originally from earth. I just had this thought at like 12 am so please answer it i am really curious&lt;/p&gt;&#xA;" OwnerUserId="29264" LastActivityDate="2023-07-13T20:57:21.503" Title="If iron is a outer space material which it is then why do human body needs it" Tags="|astronomy|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25399" PostTypeId="2" ParentId="25398" CreationDate="2023-07-13T20:52:48.463" Score="3" Body="&lt;p&gt;Every &lt;a href=&quot;https://en.wikipedia.org/wiki/Periodic_table&quot; rel=&quot;nofollow noreferrer&quot;&gt;element&lt;/a&gt; on Earth came from outer space. Apart from hydrogen, which was formed during the Big Bang, every other element was &lt;a href=&quot;https://science.nasa.gov/origin-elements&quot; rel=&quot;nofollow noreferrer&quot;&gt;formed&lt;/a&gt; by different types of stars.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The carbon in your body was made by nuclear fusion in the interior of stars, as was the oxygen. Much of the iron in your body was made during supernovas of stars that occurred long ago and far away. The gold in your jewelry was likely made from neutron stars.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://education.nationalgeographic.org/resource/formation-earth/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth&lt;/a&gt; and asteroids formed from comic dust produced by exploding stars. Iron wasn't added as a late addition. It was an integral element from the earliest &lt;a href=&quot;https://en.wikipedia.org/wiki/History_of_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;formation of the Earth&lt;/a&gt;. When life developed on Earth, iron was already present for it to use.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-07-13T20:52:48.463" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25400" PostTypeId="2" ParentId="25398" CreationDate="2023-07-13T20:57:21.503" Score="0" Body="&lt;p&gt;Iron did not come primarily from &amp;quot;asteroids that fell onto Earth&amp;quot;. It came primarily from the original set of asteroids/boulders/whatever you want to call the solid particles that first accreted to form Earth, with a little more from the objects that hit the planet later on. In other words, iron has been a major part of Earth since primordial times, before life evolved. Lifeforms then found this iron and some of them (I would suppose most of them, in one way or another) proceeded to incorporate it into their biosystems.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2023-07-13T20:57:21.503" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25401" PostTypeId="2" ParentId="25376" CreationDate="2023-07-13T21:15:53.070" Score="2" Body="&lt;p&gt;Basically the reason is we say it isn't intercontinental.&lt;/p&gt;&#xA;&lt;p&gt;Panama differs from Egypt in two ways relevant to this question. First, even without the Suez Canal a clearly defined narrow neck exists between the &amp;quot;Asian&amp;quot; and &amp;quot;African&amp;quot; parts of Egypt, making the proposed intercontinental boundary a plausible natural one. With Panama the neck is less prominent; southern North America tapers much more gradually from Mexico to the canal.&lt;/p&gt;&#xA;&lt;p&gt;Second, eastern Panama has a much more definitive geographical feature that could serve as a boundary. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Dari%C3%A9n_Gap&quot; rel=&quot;nofollow noreferrer&quot;&gt;Darien Gap&lt;/a&gt;, with its jungle and mountains, is one of the most rugged regions on Earth. It therefore makes a good candidate for a boundary that effectively separates the continents of North and South America, like the Ural Mountains in Russia. No part of Panama is on the eastern side of this region; instead the Darien Gap spills over into northwestern Colombia and therefore all the way into &amp;quot;South America&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2023-07-13T21:15:53.070" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25403" PostTypeId="1" CreationDate="2023-07-14T15:04:12.130" Score="2" ViewCount="77" Body="&lt;p&gt;I want to find the vertical vapour flux divergence (1/g * ∂(qw)/∂z) as mentioned in section 3.3 of this paper &lt;a href=&quot;https://acp.copernicus.org/articles/20/5559/2020/#section5&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://acp.copernicus.org/articles/20/5559/2020/#section5&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;From few discussions here, I tried to plot using ncl:&lt;/p&gt;&#xA;&lt;p&gt;shum        =   mixhum_ptrh(pres,temp,rh,2) ; specific humidity in kg/kg&lt;/p&gt;&#xA;&lt;p&gt;uq          =   ua * shum                           ;vapor flux&lt;/p&gt;&#xA;&lt;p&gt;vq          =   va * shum&lt;/p&gt;&#xA;&lt;p&gt;div = uv2dvG_Wrap(uq,vq)&lt;/p&gt;&#xA;&lt;p&gt;My query is :&lt;/p&gt;&#xA;&lt;p&gt;The unit of div that I am getting is in 1/s. But what I intend to get is vertical vapor flux convergence in g  h−1  m−2  hPa−1.&lt;/p&gt;&#xA;&lt;p&gt;Are the both same or else how can I reach this unit. Kindly explain.&lt;/p&gt;&#xA;&lt;p&gt;I am wondering if I am wrong totally!&lt;/p&gt;&#xA;&lt;p&gt;Looking forward to any kind of help.&lt;/p&gt;&#xA;&lt;p&gt;Thank you&lt;/p&gt;&#xA;" OwnerUserId="29271" LastActivityDate="2023-07-14T15:04:12.130" Title="Calculating vertical vapor flux divergence from WRF model output using NCL" Tags="|wrf|moisture-flux|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25404" PostTypeId="2" ParentId="8806" CreationDate="2023-07-15T07:50:31.003" Score="0" Body="&lt;p&gt;I know two salty or brackish rivers&lt;/p&gt;&#xA;&lt;p&gt;The Desaguadero river in Bolívia and La Sorgente in Paestum, Italy.&lt;/p&gt;&#xA;&lt;p&gt;Desaguadero gets salty because the Titicaca lake has some salt in it, however when its waters reach the Poopo lake, which is a huge salt plain then the water gets hyper saline. That area is Rich with salt just like any desert. All deserts have huge amounts of salt, that's exactly why they have become deserts. Due to salt.&lt;/p&gt;&#xA;&lt;p&gt;La Sorgente is brackish from the Source at Capo di Fiume, in Paestum. It springs out already brackish. There must be contact of the water with the salt mines underground.&lt;/p&gt;&#xA;&lt;p&gt;It is a fallacy of pseudo scientists that rivers carry salt to lakes and oceans, salt is already there! There are huge salt mines underground,  like the ones under the Great Lakes. The springs located on the bottom of these Lakes inject fresh water, just like most springs on Earth, including the springs under the ocean! Nearly all springs inject freshwater. The water of rivers, Lakes and oceans become salty due to contact with salt mines.&lt;/p&gt;&#xA;&lt;p&gt;Most salt mines have been exposed after the big flood described in the bible. However many of them resisted the flood and remain underground. According to the bible , water was injected into Earth from underneath,  by springs. All that pressure of water must have burst open many salt mines , like the Dead Sea or any other salt depression. The ones under the great lakes resisted the pressure, and remain springing freshwater and collecting water from the drain on the niagara river without contact with the salt mines underground.  Those salt mines are considered the biggest on Earth and if there were collapse of that area and the water came into contact with the salt, then the whole of the USA and Canada could become a desert just like the west of the USA  where the salt was visibly exposed and salt lakes are abundant and the land is dry. There are lots of salt depressions in the West of the USA,  some dry and some still covered by lakes.&lt;/p&gt;&#xA;" OwnerUserId="29278" LastEditorUserId="29278" LastEditDate="2023-07-26T01:29:26.643" LastActivityDate="2023-07-26T01:29:26.643" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25406" PostTypeId="1" AcceptedAnswerId="25411" CreationDate="2023-07-15T21:01:05.147" Score="5" ViewCount="234" Body="&lt;p&gt;It is often said that meat is among the most damaging foods from a climate change perspective. However, I don't quite understand why that is true, in the long run.&lt;/p&gt;&#xA;&lt;p&gt;Disclaimer: I am a vegan for animal rights reasons, however I still want to understand those who make the environmental case against beef.&lt;/p&gt;&#xA;&lt;p&gt;If I understand correctly, the primary contribution of beef production to climate change is the burping and farting the cows do when they digest their food.&lt;/p&gt;&#xA;&lt;p&gt;Now, all carbon dioxide emitted by human and animal bodies should be carbon neutral. This is because we get our carbon from the food we eat and that food was just recently grown, the plants having built themselves out of carbon from the atmosphere. Thus, so long as we don't eat coal, we are all solar powered with a delay of a few months (or slightly longer, for non-vegans). The same must be true for farts, except that because methane is far more potent (maybe 20-30 times) as a greenhouse gas, it does more damage, once emitted, than the CO2 (captured a few months prior) that it is replacing. However, methane in the atmosphere is short lived: It breaks down to carbon dioxide after only about 12 years. So shouldn't this mean any environmental damage from cow burps and farts is temporary, lasting only 12 years? And shouldn't this mean that if meat consumption remains constant the planet would only warm a little for that amount of meat consumption and not continue warming?&lt;/p&gt;&#xA;" OwnerUserId="29281" LastActivityDate="2023-07-18T08:33:05.913" Title="Why do cow burps and farts harm the planet?" Tags="|climate-change|methane|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25407" PostTypeId="1" CreationDate="2023-07-16T13:10:58.077" Score="6" ViewCount="1458" Body="&lt;p&gt;Does air in the atmosphere suffer friction in some way due solely to the planet's rotation?&lt;/p&gt;&#xA;" OwnerUserId="27529" LastEditorUserId="543" LastEditDate="2023-07-17T05:10:12.970" LastActivityDate="2023-07-18T00:55:21.840" Title="Does air in the atmosphere get friction due to the planet's rotation?" Tags="|atmosphere|earth-rotation|thermodynamics|fluid-dynamics|air|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25408" PostTypeId="2" ParentId="25407" CreationDate="2023-07-16T19:24:54.730" Score="3" Body="&lt;p&gt;The short answer is yes.&lt;/p&gt;&#xA;&lt;p&gt;Whenever a fluid moves against something else it will experience &lt;a href=&quot;https://www.cambridge.org/core/books/abs/atmospheric-dynamics/friction-and-boundary-layers/E34F4EFCEC07EF5D7A4F0C37B6ACEC75&quot; rel=&quot;nofollow noreferrer&quot;&gt;friction&lt;/a&gt;, it's a function of fluid dynamics.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The atmosphere is a weakly viscous fluid, but friction is important wherever the velocity gradient is very large. The frictional effect is therefore strong at least in a layer next to the surface of the Earth. Such a layer is called the boundary layer.&lt;/p&gt;&#xA;&lt;p&gt;The amount of friction the atmosphere experiences depends on the roughness of the Earth. Over flat terrain it will experience less friction than over rough terrain such as mountains, forests or tall buildings.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.britannica.com/science/planetary-boundary-layer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Planetary Boundary Layer&lt;/a&gt; (PBL) or Atmospheric Boundary Layer is the part of the atmosphere that makes contact with the Earth's surface.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;As a result of surface friction, winds in the PBL are usually weaker than above and tend to blow toward areas of low pressure.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2023-07-16T19:50:03.963" LastActivityDate="2023-07-16T19:50:03.963" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25409" PostTypeId="1" CreationDate="2023-07-17T02:49:53.653" Score="1" ViewCount="33" Body="&lt;p&gt;I am trying to understand how Cirrus Vertebratus are formed.&lt;/p&gt;&#xA;&lt;p&gt;My book and many web pages simply say &amp;quot;waves orthogonally to the initial cloud formation direction, in fitting conditions, forming clouds in up movement and no clouds in down movement&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;So is the initial cloud moved from its starting position and leaves trails, or, is wind brushing through it, then how can the trails be on both sides of the initial cloud? Why are the trails left and right occuring only next to the cloud?&#xA;searching for an animation or something, I cant find videos online that &amp;quot;simulate&amp;quot;/visualize it. How do the waves happen? Is it light hot air brushing above dense colder air, or, the other way around, I've read both in my book.&lt;/p&gt;&#xA;&lt;p&gt;Do you have any source that explains it more thouroughly?&lt;/p&gt;&#xA;&lt;p&gt;Please excuse me if I use any terms wrongly, I am just trying to learn about it, and I am new, you need to start somewhere. Thank you in case any answers happen!&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DrECY.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DrECY.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29287" LastEditorUserId="29287" LastEditDate="2023-07-17T05:41:42.050" LastActivityDate="2023-07-17T05:41:42.050" Title="Visualization of formation of cirrus vertebratus?" Tags="|meteorology|wind|clouds|aerosol|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25410" PostTypeId="2" ParentId="25407" CreationDate="2023-07-17T05:03:38.493" Score="3" Body="&lt;p&gt;Since you say &amp;quot;due solely to the planet's rotation&amp;quot;, the best answer might be &amp;quot;No.&amp;quot; The atmosphere rotates as a body with the planet. The interplanetary medium is so diffuse there is essentially no friction between it and the atmosphere. Whenever there is a pressure difference between one location on the earth's surface and another nearby place, there is a force tending to cause wind from the higher pressure to the lower pressure location, and a friction force resisting that. But the planet's rotation does not apply any sideways force on the atmosphere, since the atmosphere is already rotating too. So there is no force for friction to resist, and therefore no friction caused solely by the earth's rotation.&lt;/p&gt;&#xA;" OwnerUserId="22292" LastEditorUserId="22292" LastEditDate="2023-07-18T00:55:21.840" LastActivityDate="2023-07-18T00:55:21.840" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25411" PostTypeId="2" ParentId="25406" CreationDate="2023-07-17T06:59:20.247" Score="3" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;If I understand correctly, the primary contribution of beef production to climate change is the burping and farting the cows do when they digest their food.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;There are other important factors, such as deforestation for growing animal fodder.  However, burping is a real issue as well.&lt;/p&gt;&#xA;&lt;p&gt;As you've already pointed out, cows burp &lt;strong&gt;methane&lt;/strong&gt;, not carbon dioxide.  Methane is a much stronger greenhouse gas than carbon dioxide.  Therefore, any process that turns carbon dioxide into methane and then releases it into the atmosphere contributes to climate change in the short-to-medium term.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;However, methane in the atmosphere is short lived: It breaks down to carbon dioxide after only about 12 years. So shouldn't this mean any environmental damage from cow burps and farts is temporary, lasting only 12 years? And shouldn't this mean that if meat consumption remains constant the planet would only warm a little for that amount of meat consumption and not continue warming?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I think 12 years is the half-life, not the total lifetime.  But even with constant meat consumption, that means there's constantly a higher level of methane in the atmosphere.  If we're unlucky, this triggers a climate threshold.&lt;/p&gt;&#xA;" OwnerUserId="6" LastActivityDate="2023-07-17T06:59:20.247" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25412" PostTypeId="1" CreationDate="2023-07-17T15:52:21.490" Score="2" ViewCount="52" Body="&lt;p&gt;With recent news about hottest global daily temps on record, I came across climatereanalyzer.org from the University of Maine.&lt;/p&gt;&#xA;&lt;p&gt;I ended up looking at their &lt;a href=&quot;https://climatereanalyzer.org/clim/sst_daily&quot; rel=&quot;nofollow noreferrer&quot;&gt;data for daily sea surface temperature&lt;/a&gt; and noticed that all other years substantially overlap with at least several other years in their trend.&lt;/p&gt;&#xA;&lt;p&gt;The same is true for 2023 until early March, when the OISST data increases rapidly so that by mid-March it no longer overlaps with any other years. In addition, the divergence seems to be continually increasing since then.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/SySBa.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SySBa.png&quot; alt=&quot;OISST chart showing temperature divergence in 2023&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Is there something wrong with the OISST data or does this represent an actual change in SST?&lt;/p&gt;&#xA;&lt;p&gt;I know next to nothing about this topic but I do note that this time period appears to correspond very closely with the Canadian wildfires. Is it possible atmospheric conditions from the fires have skewed the global record?&lt;/p&gt;&#xA;" OwnerUserId="29289" LastEditorUserId="29289" LastEditDate="2023-08-21T21:23:43.273" LastActivityDate="2023-08-21T21:23:43.273" Title="Why does OISST trend for this year appear to be increasingly diverging from the mean since early March?" Tags="|climate-change|climate-models|wildfire|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25414" PostTypeId="2" ParentId="25354" CreationDate="2023-07-17T17:11:30.957" Score="0" Body="&lt;p&gt;The expression &amp;quot;the sun sets in the west&amp;quot; means that it is generally in the west compared to North, South, or East. It is not meant to say that it sets due west.&lt;/p&gt;&#xA;&lt;p&gt;The position on the horizon where the Sun rises or sets can be calculated from the declination (dec) of the Sun (or any object) and latitude (lat) of the observer using&#xA;&lt;span class=&quot;math-container&quot;&gt;$$cos(\theta_R)=-sin(dec)/cos(lat)$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$\theta_R$&lt;/span&gt; is measured from due south (for us living in the northern hemisphere).&lt;/p&gt;&#xA;&lt;p&gt;The Sun's maximum declination is +23.5 around June 21. If at 40 N latitude, the sun rises 121 degrees from due south (placing it at 180-121=58 degrees azimuth which is between NE and NNE). The sunset occurs between the WNW and NW (at 180+121=301 degrees azimuth).&lt;/p&gt;&#xA;&lt;p&gt;The Sun's minimum declination is -23.5 around December 21. Sun rise and set are at 121 degrees (between SSE and SE) and 239 degrees azimuth (between SW and SSW), respectively.&lt;/p&gt;&#xA;&lt;p&gt;(All values are approximate in my calculations.)&lt;/p&gt;&#xA;" OwnerUserId="19137" LastActivityDate="2023-07-17T17:11:30.957" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25415" PostTypeId="2" ParentId="25406" CreationDate="2023-07-18T08:33:05.913" Score="1" Body="&lt;p&gt;In addition to all the valid points given in gerrit's answer, a critical part of the methane emissions from livestock is emmitted from their manure. Once solid and liquid manure (their poop and their pee-pee) are stored together like in a typical stable in industrial agriculture anaerobic microbes process the nitrogen present in both mainly into methane. This is in contrast to letting livestock graze on pasture, where they naturally do not poop in the same place they pee and carefully till the soil with their hoof - both of which lead to nitrogen fixation into the soil such that far less nitrogen (in the form of methane) is emitted to the air.&lt;/p&gt;&#xA;&lt;p&gt;In fact, pasture feeding (especially in locations where crop-based agriculture is not possible) has a considerably better ecological and climate impact than industrial, stable-based holding of livestock.&lt;/p&gt;&#xA;" OwnerUserId="28529" LastActivityDate="2023-07-18T08:33:05.913" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25417" PostTypeId="2" ParentId="7485" CreationDate="2023-07-18T15:06:07.583" Score="0" Body="&lt;p&gt;This is not about the Math involved but, the Question of what really is the Shortest distance between two points on the surface of a Sphere. But,what seems to be missing when explaining this topic is. There are &amp;quot;two&amp;quot; Geodesic arcs between any two points on the surface of a Sphere both equidistant and,a mirror image of each other unless, the points are 180 degrees apart  then it would be &amp;quot;0ne&amp;quot; path only over the curve. Thank You .&lt;/p&gt;&#xA;" OwnerUserId="29297" LastEditorUserId="29297" LastEditDate="2023-07-18T15:08:13.537" LastActivityDate="2023-07-18T15:08:13.537" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25418" PostTypeId="2" ParentId="18920" CreationDate="2023-07-18T15:36:53.847" Score="-1" Body="&lt;p&gt;Eh; what about heat tiles? Tiles that take heat and turn it into electricity?https://en.wikipedia.org/wiki/Thermoelectric_generator&#xA;I wanted to build an e-bike powered by these and cross the Arizona desert into Las Vegas (just a dumb dream).&#xA;But; do not these tiles fulfil the fundamental conversion required (on a much larger scale) to solve this problem?&#xA;I'm not a scientist. Don't beat up on people for having a desire to save our planet. Like the planet needs that; eh?&lt;/p&gt;&#xA;" OwnerUserId="29298" LastActivityDate="2023-07-18T15:36:53.847" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25419" PostTypeId="1" AcceptedAnswerId="25420" CreationDate="2023-07-19T03:05:30.783" Score="0" ViewCount="41" Body="&lt;p&gt;In &lt;a href=&quot;https://reliefweb.int/report/iran-islamic-republic/iran-national-disaster-meeting-be-held-tehran&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; site (published on 6 November 2001) I found the following information:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Historical data suggest there is a major earthquake in Tehran every 158 years and the last one there was in 1830.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.m.wikipedia.org/wiki/1990_Manjil%E2%80%93Rudbar_earthquake&quot; rel=&quot;nofollow noreferrer&quot;&gt;1990 Manjil-Rudbar earthquake&lt;/a&gt; occured 160 years after the last major earthquake in Tehran, just 2 years after reaching the 158 years interval.&lt;/p&gt;&#xA;&lt;p&gt;Can we say the 1990 earthquake postponed a major earthquake in Tehran for another century?&lt;/p&gt;&#xA;&lt;p&gt;It's true that the fault that caused the 1990 earthquake differs from the fault that caused the 1830 one; but the epicenters are close in a geographical sense and the seismic energy of the Earth got evacuated well in the region after the 1990 earthquake.&lt;/p&gt;&#xA;&lt;p&gt;There was alao a 5.2 magnitude earthquake near Tehran on &lt;a href=&quot;https://en.m.wikipedia.org/wiki/List_of_earthquakes_in_Iran&quot; rel=&quot;nofollow noreferrer&quot;&gt;2017-12-20&lt;/a&gt;; but that can't be counted a major earthquake. The 1830 earthquake had a magnitude of 7.1.&lt;/p&gt;&#xA;&lt;p&gt;P.S. I don't know if evacuated is a good word here.&lt;/p&gt;&#xA;" OwnerUserId="29082" LastEditorUserId="29082" LastEditDate="2023-07-19T05:24:37.347" LastActivityDate="2023-07-19T05:35:05.253" Title="Did the 1990 Manjil-Rudbar earthquake postpone a massive earthquake in Tehran?" Tags="|geology|geophysics|earthquakes|seismology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25420" PostTypeId="2" ParentId="25419" CreationDate="2023-07-19T05:35:05.253" Score="2" Body="&lt;p&gt;Statements such as:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Historical data suggest there is a major earthquake in Tehran every 158 years&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;should not be interpreted as a number without variation. It is an average number of years. What the statement doesn't state is the error range for the 158 year time period.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, such a statement is a very general statement. The statement doesn't state which locations in Iran this applies to, or which fault or faults it applies to. One cannot draw to many conclusions from it.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-07-19T05:35:05.253" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25421" PostTypeId="1" AcceptedAnswerId="25422" CreationDate="2023-07-19T10:03:33.427" Score="5" ViewCount="354" Body="&lt;p&gt;So the Atlantic Ocean exhibits record-breaking temperatures currently with about &lt;strong&gt;1 degree Celsius above-average mean surface temperatures&lt;/strong&gt;. &lt;a href=&quot;https://www.sciencenews.org/article/north-atlantic-heat-record-sea-surface-temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;This&lt;/a&gt; article, for example, mentions that a more severe hurricane season might be one possible result.&lt;/p&gt;&#xA;&lt;p&gt;I was wondering if there are any educated guesses or even probable predictions as to what the short-to-mid-range influence on weather in North America, Europe, Northern Africa, and the Caribbean will be. Maybe a stronger jet stream due to a stronger meridional temperature gradient or a wetter autumn in Europe with increased evaporation?&lt;/p&gt;&#xA;" OwnerUserId="28529" LastEditorUserId="-1" LastEditDate="2023-07-20T08:10:16.003" LastActivityDate="2023-07-20T08:10:16.003" Title="Will the hot Atlantic shape global/local weather and if so, how?" Tags="|meteorology|oceanography|weather-forecasting|mesoscale-meteorology|predictability|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25422" PostTypeId="2" ParentId="25421" CreationDate="2023-07-19T12:28:24.490" Score="4" Body="&lt;p&gt;More important is the behaviour of the AMOC (Atlantic meridional overturning circulation) with developing climate change. This collapse leads to very different effects, e.g. that the water masses are distributed more poorly and heat up. This reduced heat transport in the water has effects on global scales. For example, that the trade winds increase.&lt;/p&gt;&#xA;&lt;p&gt;If you want to know more, I would recommend this paper: &lt;a href=&quot;https://www.nature.com/articles/s41558-022-01380-y&quot; rel=&quot;noreferrer&quot;&gt;https://www.nature.com/articles/s41558-022-01380-y&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2023-07-19T12:28:24.490" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25423" PostTypeId="1" CreationDate="2023-07-20T08:13:35.433" Score="3" ViewCount="77" Body="&lt;p&gt;I notice this radially symmetric weather radar pattern over London, UK today.&lt;/p&gt;&#xA;&lt;p&gt;Is this a real weather pattern, or a measurement or model artefact? If it is a real weather pattern, what causes it?&lt;/p&gt;&#xA;&lt;p&gt;The image is from &lt;a href=&quot;https://www.netweather.tv/live-weather/radar&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.netweather.tv/live-weather/radar&lt;/a&gt;, which shows the following legend under the chart:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Weather Type Radar The weather type detection uses a combination of hi-resolution model data, along with ground observations to show whether rain, sleet, snow, hail or freezing rain is falling. It's an excellent guide, but bear in mind that in very localised situations some variation may occur.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The pattern seems to have started developing at around 21:35 BST today 2023-07-19.&lt;/p&gt;&#xA;&lt;p&gt;Edit: I've added an additional image that shows a more dramatic pattern from today 2023-07-22 superimposed on a real rainfall pattern, together with a red dot at postcode HP3 0EJ in the village of Bovingdon (relevant because of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Heathrow_arrival_stacks&quot; rel=&quot;nofollow noreferrer&quot;&gt;Bovingdon arrival stack&lt;/a&gt; for Heathrow airport).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Zt0Xh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Zt0Xh.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/oe6sL.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oe6sL.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29306" LastEditorUserId="29306" LastEditDate="2023-07-22T11:37:13.010" LastActivityDate="2023-07-23T06:50:50.737" Title="Radially symmetric rainfall radar pattern?" Tags="|meteorology|radar|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25424" PostTypeId="1" AcceptedAnswerId="25425" CreationDate="2023-07-20T18:11:11.513" Score="2" ViewCount="46" Body="&lt;p&gt;I am trying to understand how can I model the travel time of tsunami waves generated by volcanic explosions? I want to analyze the 2022 Tonga tsunami. I have been using the UNESCO CoMIT software with tsunamis generated by underwater earthquakes but not with volcanic eruptions, so any suggestions would be great.&lt;/p&gt;&#xA;" OwnerUserId="27360" LastEditorUserId="2470" LastEditDate="2023-07-21T00:59:08.443" LastActivityDate="2023-07-21T05:59:15.773" Title="How to model the travel time of tsunami waves generated by volcanic explosion?" Tags="|oceanography|earthquakes|volcanic-eruption|tsunami|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25425" PostTypeId="2" ParentId="25424" CreationDate="2023-07-21T05:59:15.773" Score="0" Body="&lt;p&gt;Tsunamis are shallow waves in the sense that the tsunamis have wavelengths that typically exceeds hundreds of kilometers. This is far greater than the depth any of the oceans. This means that tsunamis &amp;quot;feel&amp;quot; the bottom of the ocean, regardless of the depth of ocean water. The velocity of a shallow wave is &lt;span class=&quot;math-container&quot;&gt;$v\approx\sqrt{g d}$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$g$&lt;/span&gt; is the local acceleration due to gravitation (including fictitious centrifugal acceleration; &lt;span class=&quot;math-container&quot;&gt;$9.80665\,\text{m}/\text{s}^2$&lt;/span&gt; is a reasonable worldwide approximation) and &lt;span class=&quot;math-container&quot;&gt;$d$&lt;/span&gt; is the local depth.&lt;/p&gt;&#xA;&lt;p&gt;You will need a model of ocean depth as a function of location, the more detailed the better.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-07-21T05:59:15.773" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25426" PostTypeId="2" ParentId="25423" CreationDate="2023-07-21T09:26:20.850" Score="4" Body="&lt;p&gt;This is a measurement artifact, perhaps due to aeroplanes or misconfigured Wi-Fi.&lt;/p&gt;&#xA;&lt;p&gt;Weather radar detects not only precipitation, but also aeroplanes, birds, insects, wind turbines, mountains, and high buildings, among other things.  Additionally, active sources of interference can be ships or &lt;a href=&quot;https://journals.ametsoc.org/view/journals/bams/97/7/bams-d-15-00048.1.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;home Wi-Fi&lt;/a&gt;.  Met services, or people working at their request, routinely tell people to change their Wi-Fi settings.  Finding them in a city can be a challenge.&lt;/p&gt;&#xA;&lt;p&gt;Software that processes weather radar data for the purposes of precipitation monitoring needs to filter out those other sources; such filtering is always imperfect.  If the filter is set too strictly, light precipitation will be filtered out.  If it's set not strictly enough, artefacts such as the one in your example will remain in the data.&lt;/p&gt;&#xA;&lt;p&gt;Some artifacts show up as arcs, whereas others show up as rays.&lt;/p&gt;&#xA;&lt;p&gt;The figure below shows an example of what data may look like if they're not corrected at all.  The figure on the left is without a correction applied.  The figure on the right is corrected.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Gxvzk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Gxvzk.png&quot; alt=&quot;radar data with or without correction&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;em&gt;Source: &lt;a href=&quot;https://www.dwd.de/DE/forschung/wettervorhersage/met_fachverfahren/wetterradarverfahren/qualitaetssicherung_wetterradardaten_node.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Deutscher Wetterdienst (DWD)&lt;/a&gt;)&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;For the location in your image, I would suspect either aeroplanes or misconfigured Wi-Fi.&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="2470" LastEditDate="2023-07-23T06:50:50.737" LastActivityDate="2023-07-23T06:50:50.737" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25432" PostTypeId="1" CreationDate="2023-07-22T00:20:33.170" Score="0" ViewCount="14" Body="&lt;p&gt;@ralhecman:so why scientists say that the core of the earth is melted Iron, how that happens? if they also say that iron is the result of a dead start, and what about the other planets in the solar system,  are they also have an iron core?&lt;/p&gt;&#xA;" OwnerUserId="29324" LastActivityDate="2023-07-22T00:20:33.170" Title="iron of the core of earth" Tags="|earth-history|core|solar-terrestrial-physics|reanalysis|planetary-formation|" AnswerCount="0" CommentCount="0" ClosedDate="2023-07-22T01:18:30.367" ContentLicense="CC BY-SA 4.0" />
  <row Id="25433" PostTypeId="1" CreationDate="2023-07-22T08:41:48.820" Score="1" ViewCount="28" Body="&lt;p&gt;I want to perform tasks like crop area estimation, crop yield estimation, crop growth stage monitoring using Sentinel 2 or Landsat data for a particular region. What tech stack would I need to do that?&lt;/p&gt;&#xA;&lt;p&gt;I looked at AcrGIS but it's not free, I couldn't figure out how to do it using QGIS. Ideally I want to get it done using Python. For python, I believe I would have to:&lt;/p&gt;&#xA;&lt;p&gt;a) download the image,&lt;/p&gt;&#xA;&lt;p&gt;b) use ML for the tasks mentioned above,&lt;/p&gt;&#xA;&lt;p&gt;c) plot the results.&lt;/p&gt;&#xA;&lt;p&gt;But what data do I use to train my models? How can I determine which type of crop it is? How can I show the results like type of crop and area of crop in the map? (I think I can use leaflet for that)?&lt;/p&gt;&#xA;" OwnerUserId="29325" LastEditorUserId="2470" LastEditDate="2023-07-22T09:29:01.520" LastActivityDate="2023-07-22T09:29:01.520" Title="Tech stack for crop related information using satellte data" Tags="|remote-sensing|agriculture|python|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25434" PostTypeId="1" AcceptedAnswerId="25435" CreationDate="2023-07-22T10:16:24.470" Score="6" ViewCount="178" Body="&lt;p&gt;This is a close picture of a cliff in the north coast of Spain. As you can see, the rock is composed of multiple thin layers, alternating between dark and light materials. Could this be the result of anual freeze-thaw cycles of a glacier of something like that? I mean, each layer could roughly correspond to a year?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1WD5z.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1WD5z.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Location: &lt;a href=&quot;https://www.google.com/maps/place/43.562885,-6.306475/data=!4m6!3m5!1s0!7e2!8m2!3d43.5628849!4d-6.3064748999999996?utm_source=mstt_1&amp;amp;entry=gps&amp;amp;lucs=47068615&amp;amp;g_ep=CAESCTExLjg3LjMwMxgAINeCAyoINDcwNjg2MTVCAkVT&quot; rel=&quot;nofollow noreferrer&quot;&gt;Playa la Gairúa, Spain&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29327" LastEditorUserId="595" LastEditDate="2023-07-25T10:21:40.977" LastActivityDate="2023-07-25T10:21:40.977" Title="Do these rock layers correspond to different years?" Tags="|plate-tectonics|geologic-layers|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25435" PostTypeId="2" ParentId="25434" CreationDate="2023-07-22T11:46:33.897" Score="6" Body="&lt;p&gt;To me it looks like a &lt;a href=&quot;https://en.wikipedia.org/wiki/Mylonite&quot; rel=&quot;nofollow noreferrer&quot;&gt;mylonite&lt;/a&gt;, a type of metamorphic rock formed by intense ductile deformation. This deformation breaks the original minerals, which then recrystallize as small grains along the shear planes, resulting in this foliation. I've seen mylonites during a field trip at Cap de Creus, in the North of Spain, they look like your photo.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="2470" LastEditDate="2023-07-23T06:53:50.840" LastActivityDate="2023-07-23T06:53:50.840" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25436" PostTypeId="2" ParentId="25423" CreationDate="2023-07-22T11:54:49.917" Score="0" Body="&lt;p&gt;As @gerrit points out, this is a measurement artifact.&lt;/p&gt;&#xA;&lt;p&gt;The artifact is associated with the location of ground weather rather used by the site (see link in my edited question), rather than with planes in the Heathrow Bovingdon arrival stack, their contrails, or misconfigured WiFi (see the second image I've added to my question - in fact if I correct for the precise location of the radar in Bovingdon, the alignment with the radial pattern gets even better).&lt;/p&gt;&#xA;" OwnerUserId="29306" LastEditorUserId="2470" LastEditDate="2023-07-23T06:50:14.720" LastActivityDate="2023-07-23T06:50:14.720" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25437" PostTypeId="1" AcceptedAnswerId="25438" CreationDate="2023-07-22T20:31:20.967" Score="5" ViewCount="439" Body="&lt;p&gt;In this BBC News &lt;a href=&quot;https://www.bbc.com/news/science-environment-66229065&quot; rel=&quot;nofollow noreferrer&quot;&gt;article&lt;/a&gt;, there is a chart labelled &amp;quot;Hottest day on record globally - Daily average air temperature, 1940-2023&amp;quot;. It shows temperatures that are higher in summer and lower in winter for the northern hemisphere, which leads me to wonder what exactly this chart is showing. If it were a global average, would the temperature in summer (or winter) not be offset by the fact that the other side of the globe has its winter (or summer) at the same time?&lt;/p&gt;&#xA;&lt;p&gt;So what is the method used in this chart? Is it just for the northern hemisphere? Is it the temperature over the land mass but not over the sea? Is the data for the southern hemisphere offset by half a year? Or is the world actually hotter in July because there's more land mass in the nothern hemisphere?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/x8r3J.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/x8r3J.jpg&quot; alt=&quot;Daily average air temperature, 1940-2023&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29329" LastEditorUserId="29329" LastEditDate="2023-07-22T21:07:15.233" LastActivityDate="2023-07-23T06:46:37.983" Title="How is this global temperature chart compiled?" Tags="|meteorology|climate-change|temperature|seasons|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25438" PostTypeId="2" ParentId="25437" CreationDate="2023-07-22T21:14:26.627" Score="5" Body="&lt;p&gt;As stated in your linked article, the graph shows the global average temperature based on ERA5 reanalysis data.&lt;/p&gt;&#xA;&lt;p&gt;Typically for graphs like this you integrate the surface temperature over the whole domain (surface of earth) and normalise the result with Earth's surface area.&lt;/p&gt;&#xA;&lt;p&gt;A short explanation for the seasonal cycle is that the northern hemisphere has more land surface area (less water surface area) compared to the southern hemisphere. Water surfaces heat much slower than land surfaces, which introduces a phase lag with respect to the solar heating. Very simplified think about it like this: High solar radiation in the southern hemisphere leads to high temperatures a few weeks/months later, while in the northern hemisphere high temperatures coincide with high radiation levels. This leads to the sinusoidal pattern you observed in the graph.&lt;/p&gt;&#xA;&lt;p&gt;In the introduction of &lt;a href=&quot;https://doi.org/10.1175/JCLI-D-13-00021.1&quot; rel=&quot;nofollow noreferrer&quot;&gt;this article&lt;/a&gt; you can find many nice references if you are interested in some more details. Apparently, this has been textbook knowledge since at least 1903.&lt;/p&gt;&#xA;" OwnerUserId="18833" LastEditorUserId="2470" LastEditDate="2023-07-23T06:46:37.983" LastActivityDate="2023-07-23T06:46:37.983" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25439" PostTypeId="2" ParentId="5313" CreationDate="2023-07-22T23:34:51.793" Score="0" Body="&lt;p&gt;I have seen blue clouds, but not in connection with storms. They come about in some circumstances when the Sun is about to rise* but the local weather is overcast.&lt;/p&gt;&#xA;&lt;p&gt;What happens is this: when the Sun is approaching the horizon, scattered light from the sky filters through the clouds and this filtered light appears dark blue, most notably over water away from city lights. But this indirect filtered light is faint; it will get obscured when the Sun rises and the filtered white light coming directly through the clouds takes over. The clouds gray out.&lt;/p&gt;&#xA;&lt;p&gt;*I live in a city where a largw body of water is to the East, so the effect is easier for me to see at dawn than at dusk.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2023-07-22T23:34:51.793" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25440" PostTypeId="1" AcceptedAnswerId="25441" CreationDate="2023-07-23T23:14:58.200" Score="2" ViewCount="81" Body="&lt;p&gt;In Africa, particularly in the Democratic Republic of the Congo (DRC), approximately 70% of the world's cobalt is produced. However, I'm curious about the percentage of this 70% that comes from illegal mines. It's challenging to believe that illegal mines can efficiently produce a significant portion of this cobalt. Is the majority of the cobalt production in the DRC sourced from legal and industrial mines rather than illegal ones? Can anyone provide more insights and data on the proportion of cobalt production that comes from illegal mining operations in the DRC?&lt;/p&gt;&#xA;" OwnerUserId="29335" LastEditorUserId="2470" LastEditDate="2023-07-24T00:06:06.983" LastActivityDate="2023-07-24T01:03:55.977" Title="Cobalt production in the Democratic Republic of the Congo (DRC): What percentage of the 70% production comes from illegal mines?" Tags="|minerals|mining|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25441" PostTypeId="2" ParentId="25440" CreationDate="2023-07-24T01:03:55.977" Score="0" Body="&lt;p&gt;Illegal mining in the Democratic Republic of Congo (DRC) is also referred to as artisanal mining. For a number of decades DRC has been the main source of cobalt and tantalum (via &lt;a href=&quot;https://en.wikipedia.org/wiki/Coltan&quot; rel=&quot;nofollow noreferrer&quot;&gt;coltan&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;The DRC supplies about 70 percent of the world's mined cobalt. &lt;a href=&quot;https://elements.visualcapitalist.com/ranked-the-worlds-top-cobalt-producing-countries/&quot; rel=&quot;nofollow noreferrer&quot;&gt;In 2022&lt;/a&gt;, this amounted to 145 000 t. The table below gives the production figures for the top 9 producing countries.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6rlzE.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6rlzE.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Sources vary for the amount of artisanal mining done in the DRC. &lt;a href=&quot;https://en.wikipedia.org/wiki/Cobalt#Extraction&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; states between 17 percent and 40 percent of DRC cobalt production was from artisanal mines. The &lt;a href=&quot;https://www.weforum.org/whitepapers/making-mining-safe-and-fair-artisanal-cobalt-extraction-in-the-democratic-republic-of-the-congo&quot; rel=&quot;nofollow noreferrer&quot;&gt;World Economic Forum&lt;/a&gt; states between 15 percent and 30 percent.&lt;/p&gt;&#xA;&lt;p&gt;The news item &lt;a href=&quot;https://www.abc.net.au/news/2022-02-24/cobalt-mining-in-the-congo-green-energy/100802588&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;Blood Cobalt&lt;/em&gt;&lt;/a&gt; from September 2022 illustrates the conditions artisanal mining work under in the DRC.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-07-24T01:03:55.977" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25443" PostTypeId="1" CreationDate="2023-07-25T17:17:52.423" Score="4" ViewCount="122" Body="&lt;p&gt;For a couple of years The Atlantic meridional overturning circulation AMOC has been under observation. There have been examples in the past, when sudden state changes of it lead to short term and hefty cooling on the northern hemisphere (Younger Dryas).&lt;/p&gt;&#xA;&lt;p&gt;Now there may be immediate danger of this happening in the coming decades:&#xA;&lt;a href=&quot;https://www.nature.com/articles/s41467-023-39810-w&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nature.com/articles/s41467-023-39810-w&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Pop science:&#xA;&lt;a href=&quot;https://phys.org/news/2023-07-gloomy-climate-scientists-collapse-atlantic.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://phys.org/news/2023-07-gloomy-climate-scientists-collapse-atlantic.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Quite of few papers deal with possible implications on regional and global circulation patterns. My question is, as the AMOC is one of the main drivers of the global ocean heat exchange, could a collapse lead to a (more) stable layering, and thus possibly to suboxic conditions in parts of the great ocean basins?&lt;/p&gt;&#xA;" OwnerDisplayName="user29219" LastEditorUserId="18081" LastEditDate="2023-07-26T20:15:51.307" LastActivityDate="2024-02-13T11:03:35.510" Title="Can a collapse of the AMOC lead to suboxic conditions?" Tags="|climate-change|ocean-currents|thermohaline-circulation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25444" PostTypeId="2" ParentId="2226" CreationDate="2023-07-26T02:53:26.230" Score="-4" Body="&lt;p&gt;The theory that planets and moons form from accretion is ridiculous in my opinion. Though I have never used it professionally, I have a degree in Physics.  Unless a collision between a Mars sized object and an Earth sized object occurred when both were still molten, the alleged head-on collision event probably would have completely obliterated the smaller planet and left a highly deformed Earth behind.  Had the both still been molten, fluid dynamics would come much more into play.  However, it's still highly unlikely that the remains of the Mars sized object would have remained in orbit around the Earth.&lt;/p&gt;&#xA;&lt;p&gt;Want more evidence?  Look at Mars.  Something huge did impact with Mars, but it was probably smaller than Earth's moon.  The evidence is the huge 2km deep basin in the northern hemisphere as well as the boulders strewn across much of the landscape all around the planet.  To me, it is obvious that there was a large scale impact event that caused Valles Marineris.  This same event caused enough shock to shatter the crust on the opposite side of the planet.  The debris likely orbited Mars for a very long time before the overwhelming majority rained back down on the planet.  Phobos and Deimos being the only two pieces of debris currently still in orbit.  Nevertheless, they will crash back down on the planet many years into future.&lt;/p&gt;&#xA;&lt;p&gt;Following what I stated above, it's easy to see where something similar would have happened had Earth been struck by a Mars sized object; only the damage would have been much more severe as I stated above.&lt;/p&gt;&#xA;&lt;p&gt;Is it possible that the moon grazed Earth in the distant past prior to settling into a stable orbit?  That's a more likely scenario than a head-on collision in my opinion.  There still would have been a lot of interaction between the two bodies; including highly electrical interaction.  Thus, that could easily explain our geological findings as well as possibly the tidally locked situation.&lt;/p&gt;&#xA;" OwnerUserId="29348" LastActivityDate="2023-07-26T02:53:26.230" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25445" PostTypeId="1" AcceptedAnswerId="25446" CreationDate="2023-07-26T04:44:37.017" Score="2" ViewCount="35" Body="&lt;p&gt;I am working to create &lt;a href=&quot;https://bigladdersoftware.com/epx/docs/8-3/auxiliary-programs/energyplus-weather-file-epw-data-dictionary.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Energy Plus Weather (EPW) Actual Meteorological Year (AMY) files&lt;/a&gt; from &lt;a href=&quot;https://www.nco.ncep.noaa.gov/pmb/products/hrrr/hrrr.t00z.wrfsfcf00.grib2.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA HRRR Model analysis&lt;/a&gt;. The provided links detail the 35 parameters required for the AMY model and variables provided by the HRRR analysis. Most of these parameters are easily found with minor unit conversions. However, the AMY file requires the following in units of Wh/m&lt;sup&gt;2&lt;/sup&gt;:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Extraterrestrial Horizontal Radiation&lt;/li&gt;&#xA;&lt;li&gt;Extraterrestrial Direct Normal Radiation&lt;/li&gt;&#xA;&lt;li&gt;Horizontal Infrared Radiation Intensity&lt;/li&gt;&#xA;&lt;li&gt;Global Horizontal Radiation&lt;/li&gt;&#xA;&lt;li&gt;Direct Normal Radiation&lt;/li&gt;&#xA;&lt;li&gt;Diffuse Horizontal Irradiance&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Unfortunately, HRRR radiation-related variables are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Upward Long-Wave Rad. Flux&lt;/li&gt;&#xA;&lt;li&gt;Downward Short-Wave Radiation Flux&lt;/li&gt;&#xA;&lt;li&gt;Downward Long-Wave Rad. Flux&lt;/li&gt;&#xA;&lt;li&gt;Upward Short-Wave Radiation Flux&lt;/li&gt;&#xA;&lt;li&gt;Upward Long-Wave Rad. Flux&lt;/li&gt;&#xA;&lt;li&gt;Cloud Forcing Net Solar Flux&lt;/li&gt;&#xA;&lt;li&gt;Visible Beam Downward Solar Flux&lt;/li&gt;&#xA;&lt;li&gt;Visible Diffuse Downward Solar Flux&lt;/li&gt;&#xA;&lt;li&gt;Upward Short-Wave Radiation Flux&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I am struggling to convert the HRRR variables to the required AMY parameters. I understand from &lt;a href=&quot;https://earthscience.stackexchange.com/questions/5439/shortwave-and-longwave-radiation-terminology-direct-beam-par-flux&quot;&gt;this post&lt;/a&gt; that beam and direct are synonymous, however I am unsure how to calculate the extraterrestrial and horizontal infrared radiation from this data as well as global position and time.&lt;/p&gt;&#xA;&lt;p&gt;Are there any suggestions on how to approximate these values from the data I have and known approximations?&lt;/p&gt;&#xA;" OwnerUserId="29349" LastEditorUserId="2470" LastEditDate="2023-07-26T10:14:54.853" LastActivityDate="2023-07-27T20:20:45.873" Title="Estimate EPW AMY parameters from HRRR Analysis" Tags="|atmosphere-modelling|measurements|numerical-modelling|atmospheric-radiation|radiation-balance|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25446" PostTypeId="2" ParentId="25445" CreationDate="2023-07-26T14:41:34.207" Score="1" Body="&lt;p&gt;The &lt;a href=&quot;https://www.homerenergy.com/products/pro/docs/3.11/how_homer_calculates_the_radiation_incident_on_the_pv_array.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;HOMER documentation for solar radiance&lt;/a&gt; Describes how Extraterrestrial Horizontal Radiation and Extraterrestrial Direct Normal Radiation are calculated. &lt;strong&gt;These are theoretical quantities&lt;/strong&gt; that describe radiation at the surface of the Earth's atmosphere before atmospheric losses and absorption. These can be estimated as a function of &lt;code&gt;day of year&lt;/code&gt;, &lt;code&gt;solar zenith angle&lt;/code&gt;, and &lt;code&gt;solar constant&lt;/code&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Extraterrestrial Direct Normal Radiation&lt;/strong&gt; (&lt;span class=&quot;math-container&quot;&gt;$G_{on}$&lt;/span&gt;) is the radiation that strikes a surface &lt;em&gt;normal to the sun's rays&lt;/em&gt; at the edge of the atmosphere and is calculated as:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$G_{o n}=G_{s c}\left(1+0.033 \cdot \cos \frac{360 n}{365}\right)$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where &lt;span class=&quot;math-container&quot;&gt;$G_{sc}$&lt;/span&gt; is the solar constant which generally has a value of 1,367 &lt;span class=&quot;math-container&quot;&gt;$W$&lt;/span&gt;/&lt;span class=&quot;math-container&quot;&gt;$m^2$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$n$&lt;/span&gt; is the day of the year.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Extraterrestrial Horizontal Radiation&lt;/strong&gt; (&lt;span class=&quot;math-container&quot;&gt;$G_o$&lt;/span&gt;) is the radiation that strikes a horizontal surface at the edge of the atmosphere and is calculated using the solar zenith angle &lt;span class=&quot;math-container&quot;&gt;$\theta_z$&lt;/span&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$G_o = G_{on}\cos(\theta_z)$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://bigladdersoftware.com/epx/docs/8-3/auxiliary-programs/energyplus-weather-file-epw-data-dictionary.html#field-horizontal-infrared-radiation-intensity&quot; rel=&quot;nofollow noreferrer&quot;&gt;Energy Plus Weather documentation&lt;/a&gt; provides a Heuristic to estimate &lt;strong&gt;Horizontal Infrared Radiation Intensity&lt;/strong&gt; as a function of &lt;code&gt;dry bulb temperature&lt;/code&gt;, &lt;code&gt;dew point temperature&lt;/code&gt;, and &lt;code&gt;opaque sky cover&lt;/code&gt; based on&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Walton, G.N. Thermal Analysis Research Program Reference Manual; US Department of Commerce, National Bureau of Standards: Washington, DC, USA, March 1983.&lt;/li&gt;&#xA;&lt;li&gt;Clark, G.; Allen, C. The estimation of atmospheric radiation for clear and cloudy skies. In Proceedings of the 2nd National Passive Solar Conference (AS/ISES), Philadelphia, PA, USA, 16–18 March 1978; pp. 675–678.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="29349" LastEditorUserId="29349" LastEditDate="2023-07-27T20:20:45.873" LastActivityDate="2023-07-27T20:20:45.873" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25447" PostTypeId="1" CreationDate="2023-07-26T17:29:42.837" Score="3" ViewCount="220" Body="&lt;p&gt;What are the potential effects of an eventual collapse of the Atlantic meridional overturning circulation (AMOC)?&lt;/p&gt;&#xA;&lt;p&gt;I often see news viting everything ranging from droughts in India to increased climate change deniers' hair loss.&lt;/p&gt;&#xA;&lt;p&gt;However, I cannot find a definitive reference on the effects of the overturning circulation halt.&lt;/p&gt;&#xA;&lt;p&gt;Does anyone feel like describing the big picture and pointing me in the right direction?&lt;/p&gt;&#xA;" OwnerUserId="6001" LastEditorUserId="18081" LastEditDate="2023-07-26T20:12:32.877" LastActivityDate="2024-01-30T11:24:29.107" Title="Collapse of the AMOC - effects" Tags="|oceanography|climatology|thermohaline-circulation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25448" PostTypeId="2" ParentId="24376" CreationDate="2023-07-27T05:08:26.707" Score="2" Body="&lt;p&gt;From a quick search online using your question, the consensus is forests emit carbon dioxide as well as absorb carbon dioxide, but overall they absorb more than they emit.&lt;/p&gt;&#xA;&lt;p&gt;From &lt;em&gt;&lt;a href=&quot;https://www.nasa.gov/jpl/nasa-finds-good-news-on-forests-and-carbon-dioxide&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA Finds Good News on Forests and Carbon Dioxide&lt;/a&gt;&lt;/em&gt;, dated 30 December 2014.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A new NASA-led study shows that tropical forests may be absorbing far more carbon dioxide than many scientists thought, in response to rising atmospheric levels of the greenhouse gas. The study estimates that tropical forests absorb 1.4 billion metric tons of carbon dioxide out of a total global absorption of 2.5 billion -- more than is absorbed by forests in Canada, Siberia and other northern regions, called boreal forests.&lt;/p&gt;&#xA;&lt;p&gt;Forests and other land vegetation currently remove up to 30 percent of human carbon dioxide emissions from the atmosphere during photosynthesis. If the rate of absorption were to slow down, the rate of global warming would speed up in return.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;On 12 February 2021, the &lt;a href=&quot;https://www.weforum.org/agenda/2021/02/forests-climate-change-carbon-absorb-environment-earth-trees/&quot; rel=&quot;nofollow noreferrer&quot;&gt;World Economic Forum&lt;/a&gt; stated:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;New research, published in &lt;a href=&quot;https://www.nature.com/articles/s41558-020-00976-6&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nature Climate Change&lt;/a&gt; and &lt;a href=&quot;https://data.globalforestwatch.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;available&lt;/a&gt; on Global Forest Watch, found that the world’s forests sequestered about twice as much carbon dioxide as they emitted between 2001 and 2019. In other words, forests provide a “carbon sink” that absorbs a net 7.6 billion metric tonnes of CO2 per year, 1.5 times more carbon than the United States emits annually.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://www.climatecouncil.org.au/deforestation/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate Council&lt;/a&gt; website, similarly stated, more that 3 years ago,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;When forests are cleared or burnt, stored carbon is released into the atmosphere, mainly as carbon dioxide. Averaged over 2015—2017, &lt;a href=&quot;https://www.climatecouncil.org.au/2017-second-worst-for-global-tropical-forest-loss/&quot; rel=&quot;nofollow noreferrer&quot;&gt;global loss of tropical forests&lt;/a&gt; contributed about &lt;a href=&quot;https://www.wri.org/insights/numbers-value-tropical-forests-climate-change-equation&quot; rel=&quot;nofollow noreferrer&quot;&gt;4.8 billion tonnes of carbon dioxide per year (or about 8-10% of annual human emissions of carbon dioxide).&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Whilst forests are important carbon sinks, meaning they draw down carbon dioxide from the atmosphere, the carbon stored in these sinks is part of an active, relatively quick carbon cycle. As living things (including trees) die and decay, the carbon that they once stored is released back into the atmosphere.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The article, &lt;a href=&quot;https://theconversation.com/explainer-how-much-carbon-can-the-worlds-forests-absorb-14816&quot; rel=&quot;nofollow noreferrer&quot;&gt;Explainer: how much carbon can the world’s forests absorb?&lt;/a&gt;, from 2013, has a similar narrative: despite being both a carbon emitter and absorber, overall forests, particularly tropical forests are an overall absorber of carbon dioxide.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2023-07-27T08:21:04.073" LastActivityDate="2023-07-27T08:21:04.073" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25450" PostTypeId="1" CreationDate="2023-07-28T06:12:59.523" Score="0" ViewCount="33" Body="&lt;p&gt;I'm very new to climate modelling and forecasting, I have chosen a project to forecast wind energy output in the future using wind speed prediction, I wish to use CMIP6 to predict. But I have very little knowledge on how it works, or how to use the model. Can anyone help me get started?&lt;/p&gt;&#xA;" OwnerUserId="29362" LastActivityDate="2023-07-28T06:12:59.523" Title="How to use CMIP6 to predict windspeed in the future?" Tags="|meteorology|wind|weather-forecasting|atmosphere-modelling|energy|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25451" PostTypeId="1" CreationDate="2023-07-28T20:17:11.457" Score="0" ViewCount="105" Body="&lt;p&gt;Land that is currently zoned as agriculture with houses and businesses surrounding it is being proposed to be changed to commercial/industrial. The purpose is to build a Manganese processing plant. The area is populated by 25000 people but scattered up into the hills. Neighbors are mostly on ranchettes of 1 to 5 acres. It is an area of natural wildlife, greenry, agriculture and practically zero light or noise pollution. This plant will be built in the middle of town. Naturally there are concerns of water, air and noise pollution.&lt;/p&gt;&#xA;" OwnerUserId="29366" LastActivityDate="2024-01-07T23:28:16.683" Title="How far should a Manganese processing plant be built from a city?" Tags="|air-pollution|groundwater|mining|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25452" PostTypeId="1" CreationDate="2023-07-29T06:59:07.050" Score="1" ViewCount="106" Body="&lt;p&gt;I have been searching for the above answer for more than 25 years.&lt;/p&gt;&#xA;&lt;p&gt;I am providing a map of Australia for comparison&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/RRbn3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RRbn3.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;http://www.bom.gov.au/climate/maps/averages/evaporation/&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://www.bom.gov.au/climate/maps/averages/evaporation/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Is evaporation rate 4000 mm/year the highest recorded in the world?&lt;/p&gt;&#xA;" OwnerUserId="29369" LastEditorUserId="2470" LastEditDate="2023-07-29T08:12:37.607" LastActivityDate="2023-07-29T08:12:37.607" Title="What is the highest evaporation rate in the world? I know evaporation rates for Australia" Tags="|meteorology|climate|hydrology|water|climate-models|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25453" PostTypeId="2" ParentId="25451" CreationDate="2023-07-29T08:40:06.147" Score="1" Body="&lt;p&gt;You might want to read my answer to: &lt;a href=&quot;https://earthscience.stackexchange.com/questions/20136/urgent-please-help-where-can-i-find-worldwide-standards-of-manganese-mining&quot;&gt;&lt;em&gt;Urgent, Please help, where can I find worldwide standards of manganese mining?&lt;/em&gt;&lt;/a&gt;.  The question is about mining, not processing plants, &lt;strong&gt;but&lt;/strong&gt; it has four weblinks that provide information regarding health concerns regarding manganese.&lt;/p&gt;&#xA;&lt;p&gt;Briefly, the human body requires a certain level of manganese, but &lt;strong&gt;excessive&lt;/strong&gt; levels of manganese, can lead to neurological effects in people, leading to conditions similar to Parkinson's Disease.&lt;/p&gt;&#xA;&lt;p&gt;From the &lt;a href=&quot;https://ods.od.nih.gov/factsheets/manganese-healthprofessional/&quot; rel=&quot;nofollow noreferrer&quot;&gt;US National Institutes of Health website&lt;/a&gt;,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Manganese toxicity mainly affects the central nervous system and can cause tremors, muscle spasms, tinnitus, hearing loss, and the feeling of being unsteady on one’s feet. Additional symptoms include mania, insomnia, depression, delusions, anorexia, headaches, irritability, lower extremity weakness, changes in mood and short-term memory, altered reaction times, and reduced hand-eye coordination. These signs and symptoms can progress to neuromotor impairments similar to those associated with Parkinson’s disease, including changes in gait and balance, tremor, and rigidity.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;From &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3166881/&quot; rel=&quot;nofollow noreferrer&quot;&gt;another National Institutes of Health website&lt;/a&gt;,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Chronic Mn poisoning is a recognized health hazard associated with the mining and processing of Mn ores (6–9). Although the largest source of human exposure to Mn is via water and food, additional exposure may occur through air polluted with Mn emissions (1). Mn poisoning has been linked to impaired motor skills, cognitive disorders, and metabolic processes (10–15). Environmental Mn pollution and its long-term effect on the health of the pediatric population living in Mn-mining areas is a major concern.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;That website references a study of 683 children, aged between 5 and 7 years, in manganese rich area of Ukraine and states,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Impaired growth and rickets-like skeletal deformities were observed in 33% of the children. This was a significantly higher percentage than in children in the reference region (15%). The children from the Mn-mining region also had increased salivary levels of immunoglobulin A (104.4±14.2 mcg/ml vs. 49.7±6.1 mcg/ml among the controls (p&amp;lt;0.05), increased serum alpha 1 proteinase inhibitor levels (4.93±0.21 g/l compared with 2.91±0.22 g/l for controls; p&amp;lt;0.001) and greater numbers of micronuclei in the mucous cells of the oral cavity (0.070±0.008 vs. 0.012±0.009, p&amp;lt;0.001).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I will try to elaborate further when I have time, but I would be extremely concerned if a manganese processing plant were to be established anywhere near where I live.&lt;/p&gt;&#xA;&lt;p&gt;Any manganese processing plant would have to have &lt;strong&gt;exceptional&lt;/strong&gt; dust suppression and capture systems. It would also have to be located on the downwind side of any habitable location, based on prevailing wind directions, so that any fugitive dust is more likely to be blown away from human inhabited localities. Try to obtain a prevailing wind direction map from your local weather service.&lt;/p&gt;&#xA;&lt;p&gt;Any processing plant should not be allowed to store manganese as a heap outside exposed to the weather. It should be delivered or removed  to or from the site in sealed containers that would be stored under cover.&lt;/p&gt;&#xA;&lt;p&gt;Manganese is not immediately toxic. Its affects accumulate over time.&lt;/p&gt;&#xA;&lt;p&gt;I am not aware of restrictions on the proximity of manganese processing plants to human inhabited areas. It would also depend on what type of processing the plant would be undertaking. Would it process manganese ore from a mine or is going to process manganese compounds and produce health supplements for human consumption?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;em&gt;&lt;strong&gt;Edit 8 January 2024&lt;/strong&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;New information from: &lt;a href=&quot;https://www.abc.net.au/news/2024-01-08/nt-government-groote-eylandt-mine-dust-health-concerns/103288140&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;NT government still won't investigate health concerns of mine implicated in Natasha Fyles's resignation&lt;/em&gt;&lt;/a&gt; and &lt;em&gt;&lt;a href=&quot;https://www.abc.net.au/news/2021-12-07/manganese-mine-indigenous-community/100676998&quot; rel=&quot;nofollow noreferrer&quot;&gt;'Concerning' levels of heavy metals found in people living near the world's biggest manganese mine.&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;CDC-NIOSH information about &lt;a href=&quot;https://www.cdc.gov/niosh/topics/manganese/default.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Manganese&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The picture below shows manganese dust accumulated on cars near a manganese loader at a port on Groote Eylandt.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3ijbz.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3ijbz.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Groote Eylandt, where a manganese mine has been operating for 50 years is also home to quolls, pictured below:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/z7Dqs.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/z7Dqs.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;A 2018 study of the quolls found manganese dust had a detrimental effect on the small marsupials.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The study found the animals had elevated manganese concentrations within their hair, testes, and the neocortex and cerebellum brain regions, which are responsible for sensory perception and motor function.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;One of the results such manganese exposure was a reduction in the agility and speed of the quolls.&lt;/p&gt;&#xA;&lt;p&gt;One finding from studies undertaken on Groote Eylandt was,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;Fine manganese dust within the respirable size range is found at levels exceeding international recommendations even 20km from manganese extraction, processing and storage facilities on Groote Eylandt,&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2024-01-07T23:28:16.683" LastActivityDate="2024-01-07T23:28:16.683" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25455" PostTypeId="1" CreationDate="2023-07-29T14:01:29.743" Score="1" ViewCount="33" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/39blT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/39blT.png&quot; alt=&quot;A Diagram of gravity in the vicinity of Mare Sereniatis&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is from the book &amp;quot;&lt;em&gt;Isosatsy and Flexure of the Atmosphere&lt;/em&gt;&amp;quot; by A. B. Watts. According to him, evidence for the isostatic compensation of mascons (i.e. regions of higher density material in the Moon's crust) should induce a low gravity anomaly right next to the high gravity anomaly above the mascon. Measurements show that it indeed does. But how would compensation create this low anomaly? My thinking is, that compensation means, there is less moon crust material under the mascon than right beside it. But would that not mean, there is heavier mantle material instead right beneath of it? I would be happy if someone shine light upon my confusion.&lt;/p&gt;&#xA;" OwnerUserId="29372" LastEditorUserId="2470" LastEditDate="2023-07-29T19:20:54.297" LastActivityDate="2023-07-29T19:20:54.297" Title="Why is there a low gravity anomaly right next to a high gravity anomaly next to mascons on the Moon?" Tags="|gravity|isostasy|earth-moon|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25456" PostTypeId="1" AcceptedAnswerId="25458" CreationDate="2023-07-29T16:45:44.753" Score="1" ViewCount="54" Body="&lt;p&gt;I'm a newbie in meteorology so sorry if this is a dumb question.&lt;/p&gt;&#xA;&lt;p&gt;I get the general idea of how cyclones form, but one thing I can't wrap my head around is why must the air diverge laterally when forming the spin, instead of following the original drift by Coriolis force?&lt;/p&gt;&#xA;&lt;p&gt;For example, the formation of a cyclone in the northern hemisphere, &lt;a href=&quot;https://i.stack.imgur.com/qZYHw.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qZYHw.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;why isn't it the case on the left? What really happens when the cyclone starts to form that gives its direction, before gaining the rotational inertia that sucks more air in that direction?&lt;/p&gt;&#xA;" OwnerUserId="29373" LastEditorUserId="2470" LastEditDate="2023-07-29T19:22:55.870" LastActivityDate="2023-07-29T21:22:27.260" Title="Why air laterally diverges before entering a cyclone/anticyclone?" Tags="|meteorology|atmosphere|tropical-cyclone|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25457" PostTypeId="1" CreationDate="2023-07-29T16:55:01.173" Score="2" ViewCount="25" Body="&lt;p&gt;I need CCS data for Carbon Injection monitoring for a seismic hazard study. Is there any open source data that related Carbon Injection monitoring for example seismic, wells, 1/2/3/4D seismic and etc.&lt;/p&gt;&#xA;" OwnerUserId="27982" LastActivityDate="2023-07-29T16:55:01.173" Title="Where can I get Carbon Capture Storage data?" Tags="|geology|geophysics|carbon-capture|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25458" PostTypeId="2" ParentId="25456" CreationDate="2023-07-29T19:33:10.850" Score="1" Body="&lt;p&gt;It may help to focus on how pressure centers aren't initially about rotation.&lt;/p&gt;&#xA;&lt;p&gt;Picture you are air... you start moving towards a new cyclone (because of a lowered pressure).  Straight inwards...&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1QBQtm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1QBQtm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Then you start to turn to the right because of Coriolis (in the NH).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3goINm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3goINm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;That results in only the right diagram (try adding the arrows in from other directions)&lt;/p&gt;&#xA;&lt;p&gt;The thing is, even if you managed to get a clockwise circulation like your left diagram... its basic forces don't suggest it can continue to work.  Because the two forces of note typically directing the air (horizontally) in pressure systems... both point towards the low pressure if the low is rotating clockwise; coriolis (turning to the right, NH) and the pressure gradient both pull the wind directly inward towards the center.  The circulation would cease.&lt;/p&gt;&#xA;&lt;p&gt;Circulation is all about balance.&lt;/p&gt;&#xA;&lt;p&gt;It &lt;em&gt;is&lt;/em&gt; actually indeed possible to get a clockwise low pressure circulation.  But, given those pair of forces it would need to counteract, you need something relatively hefty to make it happen.  Probably the most viable method to start up a clockwise low capable of persisting is by the tilting of vertical rotation (i.e. wind shear), which will bring a counterclockwise area of rotation north (NH) of an updraft in a thunderstorm.  (See Figure 3 from &lt;a href=&quot;https://www.researchgate.net/publication/234150968_Dynamics_Of_Tornadic_Thunderstorms/link/56b37bf308ae1f8aa45348a7/download&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dynamics Of Tornadic Thunderstorms, Klemp, 1987&lt;/a&gt;)  So this means there are clockwise rotating &lt;a href=&quot;https://en.wikipedia.org/wiki/Mesocyclone&quot; rel=&quot;nofollow noreferrer&quot;&gt;mesocyclones&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;From there, you can have enough rotation speed that centrifugal force can begin to be a bigger factor, which does point outwards [that's the balance that keeps satellites rotating around the planet... gravity pulls them in... centrifugal force pushes them out... result is they can maintain their height].  And that can allow them to persist, and even tighten up... &lt;a href=&quot;https://www.youtube.com/watch?v=cYsznAuvKLs&quot; rel=&quot;nofollow noreferrer&quot;&gt;leading to anticyclonic tornadoes&lt;/a&gt;, which are indeed low pressures that are rotating clockwise.&lt;/p&gt;&#xA;&lt;p&gt;There are other options for forced clockwise circulation, like a downdraft/rear inflow jet surging, leading to a diagram like this one from &lt;a href=&quot;https://www.spc.noaa.gov/misc/AbtDerechos/bowechoprot.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;SPC's bow echo education&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ASWhH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ASWhH.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(Note the anticyclonic on the bottom)&lt;br /&gt;&#xA;However, these tend to weaken more/aren't in a favorable spot for continuation.&lt;/p&gt;&#xA;&lt;p&gt;But it's only that such clockwise rotation can't develop &amp;quot;on its own&amp;quot; without those additional forces/motions circumstances helping, and then needs just the right balance to continue (counterclockwise rotation does need just the right balance too, but those two opposing forces mentioned [PGF+Coriolis] tend to really help the balance be much more stable in the face of disturbance).&lt;/p&gt;&#xA;&lt;p&gt;For a little more discussion of the balancing tendency in a cyclonic (counterclockwise in NH) low pressure, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/24306/in-geostrophic-wind-what-is-the-mechanism-behind-the-tendency-of-the-coriolis-e/24327&quot;&gt;see also this question here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2023-07-29T21:22:27.260" LastActivityDate="2023-07-29T21:22:27.260" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25460" PostTypeId="1" CreationDate="2023-07-30T14:10:15.130" Score="13" ViewCount="2403" Body="&lt;p&gt;If lava is nothing but magma breaking through the earth's surface, then why is basalt more dense than granite?&lt;/p&gt;&#xA;&lt;p&gt;I understand that something happens during the cooling process, but cannot find any comprehensive answer.&lt;/p&gt;&#xA;" OwnerUserId="29378" LastEditorUserId="24938" LastEditDate="2023-07-31T17:42:00.170" LastActivityDate="2023-07-31T17:42:00.170" Title="Why is basalt denser than granite?" Tags="|geology|plate-tectonics|volcanology|rocks|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25461" PostTypeId="2" ParentId="25460" CreationDate="2023-07-30T18:08:05.100" Score="20" Body="&lt;p&gt;Magmas have a wide range of chemical (and mineralogical) compositions. Basalts come from &lt;em&gt;mafic&lt;/em&gt; magmas (they used to be called &amp;quot;basic&amp;quot; magmas), while granites come from &lt;em&gt;felsic&lt;/em&gt; magmas (used to be &amp;quot;acid&amp;quot;). (The reasons for such diversity is out of scope of the question ; you can look for &amp;quot;magmatic differentiation&amp;quot;.) It is this difference in chemistry that creates the difference in density. Felsic magmas are enriched in silica, which is light, while mafic magmas contain more heavy oxides such as &lt;span class=&quot;math-container&quot;&gt;$\ce{FeO}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\ce{Fe2O3}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\ce{CaO}$&lt;/span&gt;... Here are two geochemical analyses (in wt%) from the USGS &lt;a href=&quot;https://www.usgs.gov/centers/gggsc/science/usgs-geochemical-and-microanalytical-reference-materials-distribution&quot; rel=&quot;noreferrer&quot;&gt;Geology, Geophysics, and Geochemistry Science Center&lt;/a&gt;. BHVO-2 is a basalt from Kilauea while G-3 is a granite from Rhode Island. Both are used worldwide as rock standards for analytic calibration.&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th&gt;Oxide&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;BHVO-2&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;G-3&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{SiO2}$&lt;/span&gt;&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;49.60&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;68.66&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{Al2O3}$&lt;/span&gt;&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;13.44&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;15.92&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{CaO}$&lt;/span&gt;&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;11.40&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;1.830&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{Fe2O3T}$&lt;/span&gt;&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;12.39&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;2.866&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{K2O}$&lt;/span&gt;&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;0.5130&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;4.57&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{MgO}$&lt;/span&gt;&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;7.257&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;0.75&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{MnO}$&lt;/span&gt;&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;0.1690&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;0.0363&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{Na2O}$&lt;/span&gt;&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;2.219&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;3.968&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{P2O5}$&lt;/span&gt;&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;0.2685&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;0.136&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{TiO2}$&lt;/span&gt;&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;2.731&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;0.476&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;&#xA;&lt;p&gt;Of course these are just examples. There are basalts containing more potassium, or granites containing less aluminum, and these main rock types can be further divided depending on these criteria (e.g., a basalt can be alkali or subalkali; high-K, medium-K or low-K, etc., see &lt;a href=&quot;https://doi.org/10.1017/CBO9780511535581&quot; rel=&quot;noreferrer&quot;&gt;Le Maitre et al. 2002&lt;/a&gt; for a full classification). But overall the difference in silica content is always huge.&lt;/p&gt;&#xA;&lt;p&gt;Note that mafic magmas can also stay in the crust and crystalize, like granite, yielding a rock called gabbro. Conversely, felsic magmas can erupt at the surface, yielding a rock called rhyolite.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastEditorUserId="18081" LastEditDate="2023-07-31T12:49:59.270" LastActivityDate="2023-07-31T12:49:59.270" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25462" PostTypeId="1" CreationDate="2023-07-31T17:12:54.890" Score="1" ViewCount="58" Body="&lt;p&gt;I own a furniture business which is located next to a dog daycare.  When it rains the stench of the dog daycare appears in my space.  We recognize the smell as it is identical to what you smell when you enter the dog daycare.&lt;/p&gt;&#xA;&lt;p&gt;Can you explain why the stench appears after it rains?  We had an air duct and HVAC expert visit the dog daycare and they both agreed that it may be due to a lack of ventilation in the dog daycare.&lt;/p&gt;&#xA;&lt;p&gt;I am trying to, from a scientific perspective, explain what occurs when it rains i.e. high versus low pressure, moisture, etc. to my landlord and the gal that has the dog daycare.&lt;/p&gt;&#xA;&lt;p&gt;Much appreciate your assistance.&lt;/p&gt;&#xA;" OwnerUserId="29384" LastActivityDate="2023-07-31T17:12:54.890" Title="Odour from Tenant after it rains" Tags="|rain|barometric-pressure|air-quality|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25463" PostTypeId="1" AcceptedAnswerId="25469" CreationDate="2023-08-02T08:02:06.043" Score="7" ViewCount="113" Body="&lt;p&gt;We know that 67.3% of land mass is in the northern hemisphere, and 32.7% in the southern.&#xA;Now we go towards the north from the equator.&#xA;On which parallel the amount of landmass north of it and south of it is equal?&lt;/p&gt;&#xA;" OwnerUserId="29397" LastActivityDate="2023-08-04T14:41:11.797" Title="Which parallel divides landmass in half?" Tags="|land|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25467" PostTypeId="1" CreationDate="2023-08-03T16:24:42.557" Score="1" ViewCount="42" Body="&lt;p&gt;I really need help, I'm working on ERA5 hourly data on pressure levels. I've extracted relative humidity and temperature on several atmospheric pressure levels. I use Metpy's 'dewpoint_from_relative_humidity' function to calculate dewpoint. The table was quite large, so I use dask to create several chunks. I have the following table:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import numpy as np&#xA;import metpy as mp&#xA;import metpy.calc as mpcalc&#xA;import xarray as xr&#xA;import metpy.units as mpunit&#xA;&#xA;with dask.config.set(**{'array.slicing.split_large_chunks': True}):&#xA;    ncin_1 = xr.open_dataset(ncfname_1, engine='netcdf4').chunk('auto')&#xA;    ncin_1['t'] = ncin_1['t'] - 273.15&#xA;    ncin_1['r'] = ncin_1['r'] / 100.0&#xA;    ncin_1['r'] = ncin_1['r'].clip(min=0.01, max=1)&#xA;&#xA;# variable reprocessing with metpy unit registry&#xA;ncin_1['level'].attrs['units'] = 'hPa'&#xA;ncin_1 = ncin_1.metpy.quantify()&#xA;ncin_1['time']  = ncin_1['time'].metpy.time &#xA;ncin_1['latitude']  = ncin_1['latitude'].metpy.latitude&#xA;ncin_1['longitude']  = ncin_1['longitude'].metpy.longitude&#xA;ncin_1['level']  = ncin_1['level'].metpy.vertical&#xA;ncin_1['t'] = ncin_1['t'] * mpunit.units.degC&#xA;ncin_1['dewpoint'] = ncin_1['dewpoint'] * mpunit.units.degC&#xA;ncin_1['r'] = ncin_1['r'] * mpunit.units.dimensionless&#xA;&#xA;# pressures levels in descending order&#xA;ncin_1= ncin_1.where((ncin_1['level'] &amp;gt;= 100) &amp;amp; (test['level'] &amp;lt;= 1000), drop=True)&#xA;ncin_1=  ncin_1.sortby('level', ascending=False)&#xA;&#xA;# create a profile variable to be filled in&#xA;ncin_1['profil'] = (('time', 'level', 'latitude', 'longitude'),np.full_like(ncin_1['t'], fill_value=np.nan))&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;pre&gt;&lt;code&gt;&amp;lt;xarray.Dataset&amp;gt;&#xA;Dimensions:    (longitude: 60, latitude: 41, level: 21, time: 24836)&#xA;Coordinates:&#xA;  * longitude  (longitude) float32 -5.02 -4.77 -4.52 -4.27 ... 9.23 9.48 9.73&#xA;  * latitude   (latitude) float32 51.15 50.9 50.65 50.4 ... 41.65 41.4 41.15&#xA;  * level      (level) int32 20 50 100 150 200 250 ... 750 800 850 900 950 1000&#xA;  * time       (time) datetime64[ns] 2006-01-01 ... 2022-12-31T18:00:00&#xA;Data variables:&#xA;    r          (time, level, latitude, longitude) float32 0.03323 ... 0.7702&#xA;    t          (time, level, latitude, longitude) float32 -69.07 ... 14.25&#xA;    dewpoint   (time, level, latitude, longitude) float32 -90.23 ... 10.28&#xA;    profil     (time, level, latitude, longitude) float32 nan nan ... nan nan&#xA;Attributes:&#xA;    Conventions:  CF-1.6&#xA;    history:      2023-07-19 22:32:41 GMT by grib_to_netcdf-2.25.1: /opt/ecmw...&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;I'd like to calculate the lifted index (using metpy's lifted_index function), but first I need to calculate the parcel_profile variable. The problem is that this function is a 1D function, according to the documentation. I've made several scripts using either xarray.apply_ufunc or xarray.map_blocks.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;whit xarray.apply_ufunc :&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;pre&gt;&lt;code&gt;def wrapper_parcel_profile(pressure, temperature, dewpoint):&#xA;    return mpcalc.parcel_profile(pressure * units.hPa , temperature * units.degC , dewpoint * units.degC ).to('degC')&#xA;&#xA;&#xA;t_1000 = ncin_1['t'].metpy.sel(level=1000)&#xA;dewpoint_1000 = ncin_1['dewpoint'].metpy.sel(level=1000) &#xA;pressure = ncin_1['level'] &#xA;&#xA;ncin_1['profil'] = xr.apply_ufunc(&#xA;    wrapper_parcel_profile,  &#xA;    pressure, t_1000, dewpoint_1000,  &#xA;    input_core_dims=[['level'], ['time', 'latitude', 'longitude'], ['time', 'latitude', 'longitude']], &#xA;    output_core_dims=[['time', 'level' , 'latitude', 'longitude']],&#xA;    vectorize=True,&#xA;    dask='parallelized', &#xA;    output_dtypes=[float],&#xA;    dask_gufunc_kwargs={'allow_rechunk': True}&#xA;)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;This script runs because I'm using dask, so if I've understood correctly, as long as I don't run the ncin_1.compute() command, nothing is calculated directly. I get this error message:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;ValueError: operands could not be broadcast together with shapes (19,) (24836,41,60) (It must have something to do with ncin_1['level']?)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;with xarray.map_block :&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;pre&gt;&lt;code&gt;def wrapper_parcel_profile(pressure, temperature, dewpoint):&#xA;    return mpcalc.parcel_profile( pressure * units.hPa , temperature * units.degC , dewpoint * units.degC).to('degC')&#xA;&#xA;pressure = test['level']&#xA;t_1000 = test['t'].metpy.sel(level=1000) * units.degC&#xA;dewpoint_1000 = test['dewpoint'].metpy.sel(level=1000) * units.degC&#xA;test['profil'] = xr.map_blocks(wrapper_parcel_profile, test ,template= test['t'])&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;I get this error message when I use &amp;quot;ncin_1.compute()&amp;quot; in my database&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;TypeError: Mixing chunked array types is not supported, but received multiple types: {, }&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Is my approach the right one? Is it possible to do this simply by staying in an xarray dataset? Are the solutions I've found appropriate? Thanks in advance for your help&lt;/p&gt;&#xA;" OwnerUserId="29407" LastActivityDate="2023-08-03T16:24:42.557" Title="How to use 1D function metpy.parcel_profile in ERA5 xarray dataset open with dask" Tags="|meteorology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25468" PostTypeId="1" CreationDate="2023-08-03T20:41:55.773" Score="0" ViewCount="26" Body="&lt;p&gt;I was recently reading a paper in which nine planetary boundaries have been proposed. The paper uses modeling and literature assessment to quantify safe and just Earth system boundaries (ESBs) for climate, the biosphere, water and nutrient cycles, and aerosols at global and subglobal levels. It proposes ESBs for maintaining the resilience and stability of the Earth system and minimizing exposure to significant harm to humans from Earth system change (a necessary but not sufficient condition for justice).&lt;/p&gt;&#xA;&lt;p&gt;For aerosols, the paper defined the safe ESB defined by the interhemispheric difference in aerosol optical depth (AOD) based on evidence that a rising North/South Hemisphere difference can trigger regional-scale tipping points and cause substantial adverse effects on regional hydrological cycles, in addition to the existing Planetary boundary (PB) of 0.25–0.50 AOD based on regional considerations. Interhemispheric AOD difference and its impact on shifts in tropical precipitation are sensitive to the aerosol particle size and the latitudinal and altitudinal distribution of reflecting aerosols. Considering this and the range of these studies (approximately 0.05–0.20 of additional AOD difference), the paper assesses that these shifts may become disruptive if the interhemispheric AOD difference, currently approximately 0.0587 on average and approximately 0.1 in the boreal spring and summer, exceeds 0.15 due to air pollution or geoengineering-related aerosol asymmetries.&lt;/p&gt;&#xA;&lt;p&gt;The paper also states that a 15 μg/m3 PM2.5 concentration translates to an AOD of approximately 0.17, indicating that the just no significant harm (NSH) boundary for aerosols is more stringent than the safe regional boundary (0.25–0.50).&lt;/p&gt;&#xA;&lt;p&gt;Thus, I was thinking if someone could help me get started with the concept of quantifying the total emissions footprint for the planet (i.e. what should be its unit? how is different from the carbon footprint of the planet?).&lt;/p&gt;&#xA;" OwnerUserId="12660" LastActivityDate="2023-08-03T20:41:55.773" Title="How should one even try to start thinking about quantifying the total emissions footprint for the planet?" Tags="|atmospheric-chemistry|atmospheric-radiation|atmospheric-circulation|atmospheric-optics|atmospheric-dust|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25469" PostTypeId="2" ParentId="25463" CreationDate="2023-08-04T14:41:11.797" Score="3" Body="&lt;p&gt;Roughly half the land on Earth is north of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Tropic_of_Cancer&quot; rel=&quot;nofollow noreferrer&quot;&gt;Tropic of Cancer&lt;/a&gt; (23°N).&lt;/p&gt;&#xA;&lt;p&gt;To estimate this, I just modified the code used by @MyCarta in &lt;a href=&quot;https://earthscience.stackexchange.com/a/15139/27775&quot;&gt;their answer to &amp;quot;In the northern hemisphere only, what percentage of the surface is land?&amp;quot;&lt;/a&gt;. Using a Peters equal projection map of the world from Wikipedia, I counted the total land pixels and then found the row in the map array which divided them in half. I then converted pixel row in the map array to a latitude using the inverse of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Gall%E2%80%93Peters_projection#Formula&quot; rel=&quot;nofollow noreferrer&quot;&gt;Peters y projection formula&lt;/a&gt;.  Here are maps showing the northern and southern halves of the Earth's land.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/934Lq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/934Lq.png&quot; alt=&quot;Black and white map of Earth above 23°N&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/wvKdB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wvKdB.png&quot; alt=&quot;Black and white map of Earth below 23°N&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here is my (quick and inelegant) code:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import numpy as np&#xA;from skimage import io&#xA;from matplotlib import pyplot as plt&#xA;&#xA;# Load equal area projection map from wikipedia&#xA;url='https://upload.wikimedia.org/wikipedia/commons/e/e2/Peters_projection%2C_black.png'&#xA;total_equal_area =io.imread(url, as_gray=True)&#xA;&#xA;equal_area=total_equal_area&#xA;&#xA;# Get shape and size of map&#xA;rows, columns = np.shape(equal_area)&#xA;total_area = rows*columns&#xA;print(&amp;quot;Rows and columns in map: &amp;quot;, rows, columns)&#xA;&#xA;ocean_area  = np.sum(equal_area)&#xA;land_area = total_area - ocean_area&#xA;&#xA;print(&amp;quot;Total pixels in map: &amp;quot;, total_area,&#xA;      &amp;quot;;   Land pixels in map:  &amp;quot;, int(land_area),&#xA;      &amp;quot;\nFraction of pixels representing land:&amp;quot;,&#xA;      np.round(land_area/total_area*100, decimals=2))&#xA;&#xA;n=386&#xA;equal_area_n=total_equal_area[:n, :]&#xA;&#xA;r_n, c_n = np.shape(equal_area_n)&#xA;total_area_n = r_n*c_n&#xA;print(&amp;quot;Cutoff row: &amp;quot;, r_n, &amp;quot;;  Total land pixels above this row: &amp;quot;,total_area_n)&#xA;&#xA;ocean_area_n  = np.sum(equal_area_n)&#xA;land_area_n   = total_area_n - ocean_area_n&#xA;&#xA;# Convert rows to latitude using Pinvers of Peters y formula from&#xA;#   https://en.wikipedia.org/wiki/Gall%E2%80%93Peters_projection#Formula&#xA;latitude_n = np.degrees(np.arcsin(1-2*n/rows))&#xA;&#xA;print(np.round(total_area_n/total_area*100, decimals=1),&#xA;      &amp;quot;% of the Earth's total surface area and &amp;quot;,&#xA;      np.round(land_area_n/land_area*100, decimals=1),&#xA;      &amp;quot;% of the Earth's land area is North of Latitude: &amp;quot;,&#xA;      np.round(latitude_n, decimals=1),&amp;quot;°N&amp;quot;, sep='')&#xA;&#xA;# Plot map of area containing 50% of Earth's land&#xA;fig = plt.figure(figsize=(20,10))&#xA;ax  = fig.add_subplot(1,1,1)&#xA;ax.set_xticks([])&#xA;ax.set_yticks([])&#xA;plt.imshow(equal_area_n,cmap='gray')&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="27775" LastActivityDate="2023-08-04T14:41:11.797" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25470" PostTypeId="2" ParentId="420" CreationDate="2023-08-04T15:26:23.377" Score="-1" Body="&lt;p&gt;Because water particles move in eliptical or circular movement and since the wavelength of a tsunami is rather long (up to 500km) you see the lower part or the eliptical movement disappear on sand as it is above the sea level, which is the SWL (Still Water Level) of any wave.&lt;/p&gt;&#xA;&lt;p&gt;All waves in water do this and we can easily observe the back and forth movement of water waves, but tsunami have much longer wavelengths, that's why.&lt;/p&gt;&#xA;" OwnerUserId="29278" LastActivityDate="2023-08-04T15:26:23.377" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25471" PostTypeId="2" ParentId="421" CreationDate="2023-08-04T15:34:00.067" Score="1" Body="&lt;p&gt;It is called refraction.&#xA;Unlike most other waves, which refract at a change of media, water waves refract at a change of depth.&lt;/p&gt;&#xA;&lt;p&gt;As it gets shallower than 1/2 the wavelength,  waves begin to refract.  1/2 wavelength is the measure if the wave base. When the wave base touches the floor , the wave begins to refract, reducing its wavelength and speed, but increasing its amplitude.  If it continues to get increasingly shallower, refraction will peak and the wave will break , releasing its energy,  when the ratio between wavelength/amplitude  has reached 7:1&lt;/p&gt;&#xA;" OwnerUserId="29278" LastActivityDate="2023-08-04T15:34:00.067" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25474" PostTypeId="2" ParentId="10008" CreationDate="2023-08-04T22:43:44.593" Score="2" Body="&lt;p&gt;I’ve actually just updated the article you referenced on Wikipedia.&lt;/p&gt;&#xA;&lt;p&gt;In fact, there is no measure called “dissection rate” represented by these units that is used this way in earth science literature.  The 3.6 number in the text is merely the ratio of the total area of Franz Josef Land to its total coastline length, that is, 16,134 sq km / 4,425 km = 3.65 sq km per coastline km.&lt;/p&gt;&#xA;&lt;p&gt;This quantity shouldn’t really be called a rate, which in the Earth Sciences generally refers to a measurement whose units are divided by time, or otherwise a ratio describing the way in which one quantity changes in relation to another, because it is instead just a simple ratio of two known, fixed measurements: area and perimeter (i.e. coastline length).&lt;/p&gt;&#xA;&lt;p&gt;This particular ratio describes the degree to which a a landmass has been dissected/eroded, highly dissected landmasses having a relatively long, complex, tortuous coastlines and thus smaller ”dissection rates”, and landmasses that have not been so heavily eroded having a coastline that is much smoother—the perfectly “un-dissected” landmass would be in the shape of a circle.  A perfectly circular landmass with area equal to Franz Josef Land would have a “dissection rate” of 35.83, the highest possible number for that area.  It is an imperfect measure because it is dependent on the area—the larger the area, the greater the maximum dissection rate. What would be a better measurement is the ratio of the &lt;em&gt;square root&lt;/em&gt; of the total area to its coastline, which is constant and related to &lt;a href=&quot;https://en.wikipedia.org/wiki/Fractal_dimension%5D&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;for a perfect circle, which has the greatest area to perimeter ratio of any 2D shape, this constant is 1/(2*sqrt(pi&quot;&gt;fractal dimension&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The “dissection rate” as calculated in this Wikipedia article is also poorly conceived because it has an inverse relationship with the degree of erosion—that is, more dissection in a landmass equals a lower number, whereas one would expect that “dissection rate” should be a quantity that gets higher with more dissection.&lt;/p&gt;&#xA;&lt;p&gt;Because Franz Josef Land has been heavily glaciated since the Pleistocene and remains 85% glaciated, and because glaciers are by far the most erosive force on earth and also very massive, depressing the surface of the earth under their weight and causing more land to come into contact with the ocean at sea level, it has been thoroughly dissected.&lt;/p&gt;&#xA;&lt;h3&gt;Ratios of total area to total coastline length for Arctic Archipelagos:&lt;/h3&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th&gt;Archipelago&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Total Area, A (sq km)&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;Coastline Length, l (km)&lt;/th&gt;&#xA;&lt;th style=&quot;text-align: right;&quot;&gt;A/l&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Franz Josef Land&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;16,134&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;4,425&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;3.65&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Severnya Zemlya&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;37,000&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;2,782&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;13.30&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;New Siberian Islands&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;38,400&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;2,611&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;14.71&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Svalbard&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;62,045&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;3,587&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;17.29&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Novaya Zemlya&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;83,000&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;4,400&lt;/td&gt;&#xA;&lt;td style=&quot;text-align: right;&quot;&gt;18.86&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;&#xA;&lt;p&gt;As you can see in the table above, Franz Josef Land is much, much more dissected than any of the other archipelagos like it on the Eurasian Arctic passive margin, with a ratio of 3.65, compared to ratios of between 13 and 18.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Note: Coastline length data was not available in any reference I could find for Severnaya Zemlya and the New Siberian Islands.  I calculated the coastline lengths of these archipelagos in GIS using the Natural Earth 10m coastline and minor islands coastlines datasets, merged.  Additionally, the area given for New Siberian Islands on Wikipedia is incorrect—Encyclopedia Britannica provides the correct figure (which I also verified in GIS using an equal-area projection on the same data set).&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="24948" LastEditorUserId="24948" LastEditDate="2023-08-18T16:22:41.760" LastActivityDate="2023-08-18T16:22:41.760" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25476" PostTypeId="2" ParentId="13280" CreationDate="2023-08-05T10:40:23.240" Score="0" Body="&lt;p&gt;Nobody has mentioned the fact that on most summer days cumulus clouds will start appearing mid to late morning and come to occupy a significant proportion of the sky by mid afternoon, inevitably altering the perceived light quality&lt;/p&gt;&#xA;" OwnerUserId="29419" LastActivityDate="2023-08-05T10:40:23.240" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25478" PostTypeId="1" CreationDate="2023-08-05T19:13:46.900" Score="3" ViewCount="55" Body="&lt;p&gt;In Jonathan Martin's Book &amp;quot;Mid-Latitude Atmospheric Dynamics&amp;quot; there is a chapter dedicated to anomalies of potential vorticity (PV). The scenario shown in the image below depicts a situation, where a positive PV anomaly near tropopause moves eastwards. It is argued, that there must be ascent motion downstream the anomaly and descent motion upstream:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/aB72X.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aB72X.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The text is:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The structure of an upper-level, positive PV anomaly can be exploited&#xA;to gain insight into the relationship between positive PV advection&#xA;and cyclogenesis. Imagine a situation in which there is initially&#xA;barotropic flow (i.e. there is no ∇pθ) and the isentropes are unique&#xA;to individual isobars as shown in Figure 9.6(a). Now, if a positive,&#xA;upper-level PV anomaly enters this domain from the west, the&#xA;isentropes must deform so as to take on the characteristic structure&#xA;of a positive PV anomaly. As the PV anomaly migrates eastward,&#xA;adiabatic flow relative to the PV anomaly will head westward along the&#xA;newly sloping isentropes. Thus, there will be upward vertical motion&#xA;to the east of the anomaly and downward vertical motions to the west&#xA;as shown schematically in Figure 9.6(b).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Next this picture is confirmed using the geopotential height equation:&lt;/p&gt;&#xA;&lt;p&gt;With the definition (geostrophic) PV&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/uBBOA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uBBOA.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;this equation states simply&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GyrPE.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GyrPE.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Finally, the conclusion, drawn by this equation is:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/CqVtF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CqVtF.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;in Hoskins' seminal &lt;a href=&quot;http://speedy.aos.wisc.edu/Hoskins_etal_1985.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;publication&lt;/a&gt;, this is called the &amp;quot;Vacuum Cleaner&amp;quot; effect.&lt;/p&gt;&#xA;&lt;p&gt;My questions are:&lt;/p&gt;&#xA;&lt;p&gt;Q1: From the first place I cannot follow, why the wind flows from East to West relative to the easterly migrating anomaly: This could only be, when the anomaly moves faster eastwards than the basic wind field (assumingly from W to E). Sounds strange...&lt;/p&gt;&#xA;&lt;p&gt;Q2: Taking this wind direction relative to the anomaly as granted, where is there a region of positive PV advection? My blue arrow indicates this region of upward vertical motion: But since this region is &lt;strong&gt;completely outside&lt;/strong&gt; the PV anomaly, there is only the undisturbed &amp;quot;local average&amp;quot; of PV - I cannot see any positive PV advection using the given wind direction: Per definition of the term &amp;quot;advection&amp;quot; we have positive advection of PV whenever&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\vec v_g \cdot \vec \nabla PV_g &amp;lt; 0$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The indicated wind directs from east to west. So to achieve positive PV advection, PV must increase in an easterly direction within the indicated area. Why should that be so?&lt;/p&gt;&#xA;&lt;p&gt;The whole description is an absolute miracle for me...&lt;/p&gt;&#xA;&lt;p&gt;Note: There is a link to this topic in &lt;a href=&quot;https://physics.stackexchange.com/questions/774948/how-to-explain-vacuum-cleaner-effect-for-upper-level-pv-anomaly&quot;&gt;Physics Stack Exchange&lt;/a&gt;. Don't know in which forum the question should be better asked and where the right experts can be found...&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2023-08-05T19:33:34.620" LastActivityDate="2023-08-05T19:33:34.620" Title="How to explain &quot;Vacuum Cleaner Effect&quot; for upper level PV anomaly?" Tags="|meteorology|atmosphere-modelling|fluid-dynamics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25479" PostTypeId="1" AcceptedAnswerId="25480" CreationDate="2023-08-06T15:30:10.537" Score="12" ViewCount="2076" Body="&lt;p&gt;My book tells me that altocumulus lenticularis are not moved by wind but rather the air just flows through them without effect on their position. How come they are the only cloud type that is stationary?&lt;/p&gt;&#xA;" OwnerUserId="29287" LastEditorUserId="-1" LastEditDate="2023-08-07T20:20:25.290" LastActivityDate="2023-08-08T15:08:47.163" Title="Why aren't lenticular clouds moved by the wind?" Tags="|clouds|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25480" PostTypeId="2" ParentId="25479" CreationDate="2023-08-06T18:12:32.753" Score="23" Body="&lt;p&gt;Clouds form when particular conditions of temperature and humidity intersect.&lt;/p&gt;&#xA;&lt;p&gt;In the case of lenticular clouds, those conditions occur at specific locations slightly downwind from the tops of mountains -- a &lt;a href=&quot;https://en.wikipedia.org/wiki/Standing_wave&quot; rel=&quot;noreferrer&quot;&gt;standing wave&lt;/a&gt; forms in the air between areas of low and high humidity, much as standing waves form in river rapids.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/aSSNm.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/aSSNm.jpg&quot; alt=&quot;Niobrara standing waves&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Source: &lt;a href=&quot;https://www.nps.gov/niob/learn/nature/hydrology.htm&quot; rel=&quot;noreferrer&quot;&gt;National Park Service&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;The standing waves can only form when wind is blowing over the mountain, and so the region of air where the standing waves create the conditions to form clouds is pinned down by the mountain.&lt;/p&gt;&#xA;&lt;p&gt;The region doesn't move, but the air and water molecules do.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;New moist air blows over the mountain, following the standing wave, and into a zone of lower temperature, where it condenses into the droplets that form the cloud.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Still following the wave, the droplets blow into an area of higher temperature and evaporate again.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/l1Rxh.gif&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/l1Rxh.gif&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Source: &lt;a href=&quot;https://www.weather.gov/hfo/lenticular&quot; rel=&quot;noreferrer&quot;&gt;National Weather Service&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Also, the standing waves that guide moist air to form lenticular clouds are an example of laminar flow.&lt;/p&gt;&#xA;&lt;p&gt;Other clouds appear to move because and the air where they form is moving turbulently, and they are also not controlled by temperature (they move within a layer about the same temperature), only moisture.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2023-08-08T15:08:47.163" LastActivityDate="2023-08-08T15:08:47.163" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25481" PostTypeId="1" CreationDate="2023-08-07T02:03:16.570" Score="2" ViewCount="78" Body="&lt;p&gt;Please bear with me, since I don't know much about geography or geology.&lt;/p&gt;&#xA;&lt;p&gt;I was looking at an earth globe and noticed the pacific ocean covers virtually half of the planet (more or less). How is it even possible that this half is under water?&lt;/p&gt;&#xA;&lt;p&gt;Is it because the crust under the pacific ocean is heavier than the rest of the world? Otherwise I can't understand why it's sunk so much. Does this make sense?&lt;/p&gt;&#xA;" OwnerUserId="29427" LastEditorDisplayName="user29219" LastEditDate="2023-09-17T19:50:45.367" LastActivityDate="2023-09-17T19:50:45.367" Title="Is the earth crust under the pacific ocean heavier than in the rest of the planet?" Tags="|plate-tectonics|crust|oceanic-crust|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25482" PostTypeId="1" CreationDate="2023-08-07T08:26:36.833" Score="1" ViewCount="70" Body="&lt;p&gt;Wildfires seem to be more frequent in the southern Europe, meantime as the Arctic melts, there are speculations that the Gulf Stream might collapse, would lower the temperature &lt;a href=&quot;https://www.bbc.com/news/science-environment-66289494&quot; rel=&quot;nofollow noreferrer&quot;&gt;10-15 degrees&lt;/a&gt; in Europe. At the same time the Arctic region is getting warmer. If we were to combine all of these trends, what kind of the environment do we expect in the future? Will the geographic location of &amp;quot;cold&amp;quot; and &amp;quot;warm&amp;quot; regions going to shift or will the available regions on Earth that have &lt;em&gt;normal&lt;/em&gt; temperature amplitudes shrink?&lt;/p&gt;&#xA;" OwnerUserId="29428" LastEditorUserId="29428" LastEditDate="2023-08-07T08:27:13.053" LastActivityDate="2023-08-22T07:02:29.637" Title="Climate change impact on the geography" Tags="|climate-change|climate-models|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25483" PostTypeId="1" CreationDate="2023-08-07T18:57:07.893" Score="3" ViewCount="191" Body="&lt;p&gt;I've spent some time in the Leesburg, Virginia (USA) area and I've noticed that whenever a line of thunderstorms approaches the area, it frequently splits and goes around a particular spot just southeast of Leesburg, leaving it almost completely dry.  The locals even have a name for it.  They call it the &amp;quot;Leesburg split&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;I've been trying to investigate this and see objective confirmation that this is a real thing, perhaps with a high-resolution rainfall map of the area or a map of compounded/cumulative radar activity.  But I just can't seem to find the right tool.  Perhaps I don't know how to google for meteorological tools.  Any guidance would be appreciated.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;I would just like to see a cumulative rainfall map of the area.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="20991" LastEditorUserId="20991" LastEditDate="2023-08-14T15:37:47.170" LastActivityDate="2023-08-14T15:40:13.763" Title="Investigating the &quot;Leesburg split&quot; rainfall anomaly" Tags="|rainfall|mapping|thunderstorm|radar|united-states|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25484" PostTypeId="1" CreationDate="2023-08-07T19:14:23.207" Score="2" ViewCount="119" Body="&lt;p&gt;Rising from the ground in an airplane, I fly into the bottom of a cloud.&#xA;I can explain the bottom of the cloud as air temperature (which decreases&#xA;with altitude) being decreased to the dewpoint.&lt;/p&gt;&#xA;&lt;p&gt;I fly further up and the temperature decreases more.  The dewpoint also&#xA;decreases since water in vapor form is being removed as cloud droplets.&lt;/p&gt;&#xA;&lt;p&gt;Then, when I fly up through the top boundary of the cloud (which is very clear&#xA;in most of my flights), is the temperature still below the dewpoint?&#xA;In other words, is water condensing on particulate matter outside the&#xA;airplane even when above the cloud?&lt;/p&gt;&#xA;&lt;p&gt;I believe condensation is still occurring above the cloud even though that&#xA;seems to contradict my being outside of the cloud, so I am hoping someone&#xA;can also explain this apparent contradiction.&lt;/p&gt;&#xA;" OwnerUserId="18294" LastActivityDate="2024-01-04T23:07:55.960" Title="Is the air temperature usually below the dewpoint above the top of a cloud?" Tags="|temperature|clouds|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25486" PostTypeId="2" ParentId="25484" CreationDate="2023-08-07T21:58:29.377" Score="0" Body="&lt;p&gt;Above clouds, you're generally seeing a different layer of air which, typically, isn't cold enough to allow the lower (thus denser) air mass to continue rising.  The top of a cloud is often where the relevant air mass stopped rising and cooling, and condensation is not occurring above the cloud.  The upper mass can be dryer, so that its temperature is above the dew point.&lt;/p&gt;&#xA;&lt;p&gt;The temperature generally continues to decrease with altitude (though it can increase), but there is a minimum drop in temperature that's required for an air mass to keep rising, and the upper air mass can be colder but not enough colder for that.  The equilibrium temperature profile is described by an &lt;a href=&quot;https://glossary.ametsoc.org/wiki/Adiabatic_lapse_rate&quot; rel=&quot;nofollow noreferrer&quot;&gt;adiabatic lapse rate&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="26713" LastActivityDate="2023-08-07T21:58:29.377" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25488" PostTypeId="1" CreationDate="2023-08-09T20:50:19.050" Score="1" ViewCount="48" Body="&lt;p&gt;I was seeing the Caspian Sea from Google Maps satellite mode and I found most islands are elongated in shape (the biggest of them Ogurja ada or Ogurchinsky island).&lt;/p&gt;&#xA;&lt;p&gt;Also there are islands that have tails, like Khara Zira island and the one to the northwest of it.&lt;/p&gt;&#xA;&lt;p&gt;What's the geological reason for the existence of these islands?&lt;/p&gt;&#xA;&lt;p&gt;My hypothesis for the existence of these islands is that they aren't just underwater peaks. But short underwater mountain ranges.&lt;/p&gt;&#xA;" OwnerUserId="29082" LastEditorUserId="29082" LastEditDate="2023-08-09T22:59:31.970" LastActivityDate="2023-08-09T22:59:31.970" Title="Why are most islands in the Caspian Sea elongated and some of them even have tails?" Tags="|geology|islands|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25489" PostTypeId="1" AcceptedAnswerId="25492" CreationDate="2023-08-10T07:42:23.133" Score="0" ViewCount="86" Body="&lt;p&gt;I'm trying to derive the formula for gravitational acceleration as a function of Earth radius &lt;span class=&quot;math-container&quot;&gt;$g(r)$&lt;/span&gt;, given a spherical shell model where each shell has a constant density &lt;span class=&quot;math-container&quot;&gt;$\rho(r)$&lt;/span&gt;. If I set &lt;span class=&quot;math-container&quot;&gt;$r=0$&lt;/span&gt; to be the core-mantle boundary,&#xA;I think it's something like:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$g(r) = \frac{4\pi G}{3r^{2}}[ \int_{0}^{r}{\rho}(r)r^{2}.dr +F ]$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where &lt;span class=&quot;math-container&quot;&gt;$F$&lt;/span&gt; accounts for core mass. But I would like confirmation/references if possible!&#xA;Thanks!&lt;/p&gt;&#xA;&lt;p&gt;Edit:&#xA;Here's my thinking thus far: at a radius &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt;,&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$g(r) = \frac{G}{r^{2}}\int_{V}\rho.dV$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where &lt;span class=&quot;math-container&quot;&gt;$V$&lt;/span&gt; is the volume below &lt;span class=&quot;math-container&quot;&gt;$r$&lt;/span&gt;. Since &lt;span class=&quot;math-container&quot;&gt;$V = \frac{4\pi}{3} r^{3}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$dV = 4\pi r^{2}.dr$&lt;/span&gt;. So&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$g(r) = \frac{4\pi G}{r^{2}} \int_{0}^{r}\rho(r)r^{2}.dr$&lt;/span&gt;, plus a constant for the mass of the core.&lt;/p&gt;&#xA;" OwnerUserId="29448" LastEditorUserId="29448" LastEditDate="2023-08-10T12:39:38.327" LastActivityDate="2023-08-10T23:51:14.823" Title="What is a general formula for Earth gravity as a function of radius, given a spherical shell model?" Tags="|geophysics|gravity|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25490" PostTypeId="1" AcceptedAnswerId="25491" CreationDate="2023-08-10T10:13:55.417" Score="2" ViewCount="145" Body="&lt;p&gt;From the question &lt;a href=&quot;https://aviation.stackexchange.com/questions/88721/why-are-pressure-levels-raised-on-warm-days/88722&quot;&gt;Why are pressure levels raised on warm days?&lt;/a&gt;, my understanding is that the air pressure at surface level is not affected by temperature, as the mass of the imagined air column stays the same (even though it's extended higher due to lower density). Then, at any given true altitude, warmer temperatures would correspond to higher pressure. The air column analogy makes a lot of sense to me.&lt;/p&gt;&#xA;&lt;p&gt;However, I was reading &lt;a href=&quot;https://www.noaa.gov/jetstream/global/global-atmospheric-circulations&quot; rel=&quot;nofollow noreferrer&quot;&gt;NOAA's explanation of atmospheric circulations&lt;/a&gt;, which says &amp;quot;This region would become very hot, with hot air rising into the upper atmosphere. This would create a constant belt of low pressure around the equator&amp;quot;. That seems to contradict the concept above.&lt;/p&gt;&#xA;&lt;p&gt;My guess is, in the air column analogy, when the air column is extended higher, it's &amp;quot;leveled out&amp;quot; with the surrounding air, just like water. So we end up with the column with the same original height but lower density, meaning that the total weight at the bottom is lower than before (which means lower pressure). However, if this is true, then the pressure would be lower at any altitude, not just at the surface.&lt;/p&gt;&#xA;&lt;p&gt;I'm confused now. Please help, thank you!&lt;/p&gt;&#xA;" OwnerUserId="29449" LastEditorUserId="6298" LastEditDate="2023-08-11T08:29:14.487" LastActivityDate="2023-08-11T08:29:14.487" Title="Why do tropical areas have low air pressure?" Tags="|meteorology|temperature|barometric-pressure|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25491" PostTypeId="2" ParentId="25490" CreationDate="2023-08-10T13:47:25.327" Score="0" Body="&lt;p&gt;Your guess is correct. As the column of air gets heated, it expands, and that results in a higher pressure in the &lt;strong&gt;upper&lt;/strong&gt; troposphere.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/wK9oq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wK9oq.png&quot; alt=&quot;Image α&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As a result, the air from this warm column flows outwards along the &lt;strong&gt;tropopause&lt;/strong&gt;. This outflow of air is what causes a reduction in the net air mass within the column, and a subsequent reduction in the surface pressure. Therefore at the surface, the air will flow towards the column; so the air moves in a cyclonic sense:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xF0dy.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xF0dy.png&quot; alt=&quot;Image β&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;However, if this is true, then the pressure would be lower at any altitude, not just at the surface.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The surface pressure has indeed reduced, but so has the &lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/atmospheric-lapse-rate#:%7E:text=The%20mass%20of%20air%20above%20a%20given%20level%20decreases%20with,1%20in%20the%20lower%20atmosphere.&quot; rel=&quot;nofollow noreferrer&quot;&gt;pressure lapse rate&lt;/a&gt; (since the air has expanded upwards). Therefore, in the upper atmosphere, the pressure will actually be higher above the warm surface (as can be seen in the first image).&lt;/p&gt;&#xA;&lt;p&gt;&lt;sup&gt;(Images source: &lt;a href=&quot;https://files.moskvich.xyz/ATPL/CAE%20Oxford%20Aviation%20Academy%20-%20050%20Meteorology%20%28ATPL%20Ground%20Training%20Series%29%20-%202014.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Meteorology by Oxford&lt;/a&gt;)&lt;/sup&gt;&lt;/p&gt;&#xA;" OwnerUserId="29450" LastActivityDate="2023-08-10T13:47:25.327" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25492" PostTypeId="2" ParentId="25489" CreationDate="2023-08-10T23:41:37.490" Score="1" Body="&lt;p&gt;Properly, your formula should read&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$g(r) = \frac{4\pi G}{(r+r_c)^2}[ \int_{0}^{r}{\rho}(r)r^{2}.dr +F ]$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where your radial distance (which is the argument in the inverse square law) is measured from the center of the shells and thus includes the core radius &lt;span class=&quot;math-container&quot;&gt;$r_c$&lt;/span&gt;. Also you do not use the &lt;span class=&quot;math-container&quot;&gt;$3$&lt;/span&gt;. The mass of each shell is the surface area times the density times the shell thickness, and the surface area does not have the factor of &lt;span class=&quot;math-container&quot;&gt;$1/3$&lt;/span&gt;. Of course when you add the core mass, that is computed over a volume and thus does include the &lt;span class=&quot;math-container&quot;&gt;$1/3$&lt;/span&gt; factor if you are calling the core a homogemeous ball of radius &lt;span class=&quot;math-container&quot;&gt;$r_c$&lt;/span&gt; and density &lt;span class=&quot;math-container&quot;&gt;$\rho_c$&lt;/span&gt;. Thus &lt;span class=&quot;math-container&quot;&gt;$F=\rho_cr_c^3/3$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Otherwise your approach seems correct.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2023-08-10T23:51:14.823" LastActivityDate="2023-08-10T23:51:14.823" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25493" PostTypeId="2" ParentId="22393" CreationDate="2023-08-11T17:32:47.740" Score="2" Body="&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;There is no pacific coast to the The Laurentide Ice Sheet, you are thinking of the Cordilleran Ice Sheet.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;You are making a mistake in thinking the ice wall would be continuous. At its maximum it would look like that, but 25,000 years ago it was under retreat and would have been large patches of normal coastline with a few interspaced glaciers. It extended back out to the ocean later around 13,000 years ago.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;What would it look like when humans crossed it, sections like picture A and sections like picture B.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ZvFxY.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ZvFxY.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qeG9S.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qeG9S.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://faculty.washington.edu/dbooth/Ch_02_INQUA_volume.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://faculty.washington.edu/dbooth/Ch_02_INQUA_volume.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2023-08-11T17:32:47.740" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25495" PostTypeId="2" ParentId="7056" CreationDate="2023-08-12T21:17:12.340" Score="1" Body="&lt;p&gt;One of the simplest ways (not working I think): Ask them how can the Moon shine like a crescent if it's a flat shape like the Earth?&lt;/p&gt;&#xA;&lt;p&gt;A little harder (better working): Go on a ship journey with your flat-Earther friend from a port and come back to the same port after months. Also, in this way they will find out there is no &lt;em&gt;sudden edges&lt;/em&gt; on Earth.&lt;/p&gt;&#xA;&lt;p&gt;The hardest way (works I think): Ask them to become astronauts so that they go to space to see the Earth as a sphere by their own eyes (a sphere has shadows and/or lights on the edges just like a ball; just like a crescent Moon). Also, they can orbit around the Earth as astronauts parallel to the Equator or the Greenwich meridian. If parallel to the equator they will come back to the same spot after completion of an orbit just like the ship journey (of course, this time with a little error because of the rotation of Earth). And if parallel to the Greenwich meridian they will see the North and South Poles in each semi-orbit respectively.&lt;/p&gt;&#xA;" OwnerUserId="29082" LastEditorUserId="29082" LastEditDate="2023-08-13T08:07:27.043" LastActivityDate="2023-08-13T08:07:27.043" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25496" PostTypeId="2" ParentId="7056" CreationDate="2023-08-12T23:51:01.357" Score="4" Body="&lt;p&gt;I proved this to myself during a fishing trip a couple of years ago. I took a sequence of pictures of a well-known suspension bridge that could be seen from miles away (the boat actually passed under it). The suspension part in the middle is much higher than the ends.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/xoi7A.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xoi7A.jpg&quot; alt=&quot;first in sequence&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As I got farther and farther from the bridge, first the ends disappeared beyond the horizon, as did the lighthouse and bottoms of the suspension section's massive concrete anchors.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/nnBjK.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nnBjK.jpg&quot; alt=&quot;second in sequence&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/l7iac.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/l7iac.jpg&quot; alt=&quot;third in sequence&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/infM6.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/infM6.jpg&quot; alt=&quot;fourth in sequence&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/EL4ST.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EL4ST.jpg&quot; alt=&quot;fufth and last in sequence&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;If the Earth were flat, good binoculars could have picked out the features that disappeared.  But the curvature of the Earth was in the way.  Eventually the bridge disappeared altogether.&lt;/p&gt;&#xA;" OwnerUserId="6467" LastEditorUserId="6467" LastEditDate="2023-08-12T23:57:20.210" LastActivityDate="2023-08-12T23:57:20.210" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25497" PostTypeId="1" CreationDate="2023-08-14T04:21:59.443" Score="3" ViewCount="620" Body="&lt;p&gt;When we consider &lt;strong&gt;two oceanic&lt;/strong&gt; crusts, the older oceanic crust is heavier and the newer oceanic crust is lighter.&lt;/p&gt;&#xA;&lt;p&gt;But when we consider two crusts, one &lt;strong&gt;continental&lt;/strong&gt; and the other &lt;strong&gt;oceanic&lt;/strong&gt;, continental crust is the older one yet LIGHTER of the two; while oceanic crust, the newer one, is HEAVIER of the two.&lt;/p&gt;&#xA;&lt;p&gt;Why is that?&lt;/p&gt;&#xA;&lt;p&gt;I know that continental crust has a granite composition while oceanic crust has a basalt composition.&lt;/p&gt;&#xA;&lt;p&gt;Hence, I am not sure if the question can be reduced to: &amp;quot;&lt;strong&gt;Why is older basalt heavier than newer basalt?&lt;/strong&gt;&amp;quot; (iff that actually is the case)&lt;/p&gt;&#xA;" OwnerUserId="29378" LastEditorUserId="29378" LastEditDate="2023-08-14T04:28:02.520" LastActivityDate="2023-08-14T17:59:28.317" Title="If among oceanic crusts older means heavier, then why is old continental crust lighter than new oceanic crusts?" Tags="|oceanography|plate-tectonics|ocean-ridge|oceanic-crust|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25498" PostTypeId="2" ParentId="25497" CreationDate="2023-08-14T06:21:49.113" Score="5" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;I know that continental crust has a granite composition while oceanic crust has a basalt composition.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;That's the key. Granitic rock has a significantly higher silicon composition compared to basaltic rock and has a significantly lower iron and magnesium composition compared to basaltic rock. This results in continental crust being less dense than oceanic crust. Cooling does not change the chemical composition.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-08-14T06:21:49.113" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25499" PostTypeId="2" ParentId="25497" CreationDate="2023-08-14T17:59:28.317" Score="0" Body="&lt;p&gt;With oceanic, older crust is denser because it is cooler (old=cold=dense=faster subduction).&lt;/p&gt;&#xA;&lt;p&gt;Even when several millions of years old, the sheer thickness of the layer and the heat capacity of the rock require that there must be a lot of thermal energy locked up.&lt;/p&gt;&#xA;" OwnerUserId="29471" LastActivityDate="2023-08-14T17:59:28.317" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25502" PostTypeId="1" CreationDate="2023-08-15T08:03:21.523" Score="1" ViewCount="109" Body="&lt;p&gt;I’ve read about the Ice Albedo Feedback effect on global warming. Antarctica has had a large sea ice anomaly from late 2021 until now. What is the average change in energy flux over the period 21 June 2022 to 20 June 2023 (compared to the 2011-2020 average) because of this anomaly?&lt;/p&gt;&#xA;" OwnerUserId="29475" LastEditorUserId="29475" LastEditDate="2023-08-15T19:43:39.023" LastActivityDate="2023-08-22T07:05:38.713" Title="Estimate warming caused by the current sea ice anomaly in Antarctica" Tags="|climate-change|antarctica|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25504" PostTypeId="1" CreationDate="2023-08-15T13:00:14.797" Score="1" ViewCount="31" Body="&lt;p&gt;I once heard (read? I can't remember) an adage which stated something like this (my recall):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Show an outcrop to X geologists, you'll end up with X different&#xA;interpretations about its formation.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;(I wonder if it was not even Y interpretations, with Y &amp;gt; X.)&lt;/p&gt;&#xA;&lt;p&gt;I have a hard time finding this online with such generic keywords... As there are several geologists here, I'd like to ask:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;What is the exact wording of this adage?&lt;/strong&gt; (or let's say the most commonly found in the literature, written sources welcomed!)&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Who first said/wrote it&lt;/strong&gt;, if this can ever be tracked?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2023-08-15T13:00:14.797" Title="Source of an adage about geologists and their various interpreatations of outcrops" Tags="|terminology|history-of-science|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25505" PostTypeId="1" CreationDate="2023-08-15T20:35:42.517" Score="3" ViewCount="352" Body="&lt;p&gt;The JRA-3Q dataset is available from &lt;a href=&quot;https://search.diasjp.net/en/dataset/JRA3Q&quot; rel=&quot;nofollow noreferrer&quot;&gt;DIAS&lt;/a&gt;. There is an online interface to download what you need file-by-file.&lt;/p&gt;&#xA;&lt;p&gt;Other reanalyses like ERA5 and MERRA2 have access points that let you write a python script to get what you want (and often subset it on their servers using opendap or similar).&lt;/p&gt;&#xA;&lt;p&gt;I haven't been able to find an efficient way of downloading the JRA-3Q dataset in such a way.  Part of this is the file nomenclature that includes an obscure-looking string (e.g.&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;https://data.diasjp.net/dl/storages/file/L0pSQTNRL0NsaW05MTIwL0RhaWx5L2FubF9pc2VudHJvcC9hbmxfaXNlbnRyb3BfYnZmMi5jbGltOTEyMC5kYXkwMTA3&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;Has anyone come up with a way to download quite a lot of data in an efficient way?&lt;/p&gt;&#xA;" OwnerUserId="14348" LastActivityDate="2023-08-15T21:12:33.807" Title="Downloading JRA-3Q efficiently using a python script" Tags="|climate|open-data|python|reanalysis|climate-data|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25506" PostTypeId="2" ParentId="25505" CreationDate="2023-08-15T21:12:33.807" Score="3" Body="&lt;p&gt;The URL strings are base64-encoded, the example given decodes to:&#xA;&lt;code&gt;/JRA3Q/Client9120/Daily/anl_isentrop/anl_isentrop_bvf2.cglt9103.day0107&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;With this information, you can pretty easily figure out, for a given dataset, which parts of the string you need to replace.  Then, use the provided download script:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;#!/usr/bin/env python&#xA;&#xA;import urllib&#xA;import urllib2&#xA;import urlparse&#xA;import cookielib&#xA;import HTMLParser&#xA;import subprocess&#xA;import sys&#xA;import os&#xA;&#xA;&#xA;import optparse&#xA;import netrc&#xA;import getpass&#xA;&#xA;&#xA;class CASLoginParser(HTMLParser.HTMLParser):&#xA;    def __init__(self):&#xA;        HTMLParser.HTMLParser.__init__(self)&#xA;        self.action = None&#xA;        self.data = {}&#xA;&#xA;    def handle_starttag(self, tagname, attribute):&#xA;        if tagname.lower() == 'form':&#xA;            attribute = dict(attribute)&#xA;            if 'action' in attribute:&#xA;                self.action = attribute['action']&#xA;        elif tagname.lower() == 'input':&#xA;            attribute = dict(attribute)&#xA;            if 'name' in attribute and 'value' in attribute:&#xA;                self.data[attribute['name']] = attribute['value']&#xA;&#xA;class DIASAccess():&#xA;    def __init__(self, username, password):&#xA;        self.__cas_url = 'https://auth.diasjp.net/cas/login?'&#xA;        self.__username = username&#xA;        self.__password = password&#xA;        #self.__cj = cookielib.CookieJar()&#xA;        self.__cj = cookielib.MozillaCookieJar()&#xA;        self.__opener = urllib2.build_opener(&#xA;            urllib2.HTTPCookieProcessor(self.__cj))&#xA;&#xA;    def open(self, url, data=None):&#xA;        response = self.__opener.open(url, data)&#xA;        response_url = response.geturl()&#xA;&#xA;        if response_url != url and response_url.startswith(self.__cas_url):&#xA;            # redirected to CAS login page&#xA;            response = self.__login_cas(response)&#xA;            if data != None:&#xA;                # If POST (data != None), need reopen&#xA;                response.close()&#xA;                response = self.__opener.open(url, data)&#xA;&#xA;        return response&#xA;&#xA;    def __login_cas(self, response):&#xA;        parser = CASLoginParser()&#xA;        parser.feed(response.read())&#xA;        parser.close()&#xA;&#xA;        if parser.action == None:&#xA;            raise LoginError('Not login page')&#xA;&#xA;        action_url = urlparse.urljoin(response.geturl(), parser.action)&#xA;        data = parser.data&#xA;        data['username'] = self.__username&#xA;        data['password'] = self.__password&#xA;&#xA;        response.close()&#xA;        response = self.__opener.open(action_url, urllib.urlencode(data))&#xA;&#xA;        if response.geturl() == action_url:&#xA;            print 'Authorization fail'&#xA;            quit()&#xA;&#xA;        return response&#xA;&#xA;    def dl(self, url, path, file, data=None):&#xA;        try:&#xA;            response = self.__opener.open(url, data)&#xA;            if not os.path.exists('.' + path):&#xA;                os.makedirs('.' + path)&#xA;&#xA;            f = open('.' + path + file, 'wb')&#xA;            file_size_dl = 0&#xA;            block_size = 8192&#xA;            while True:&#xA;                buffer = response.read(block_size)&#xA;                if not buffer:&#xA;                    break&#xA;&#xA;                file_size_dl += len(buffer)&#xA;                f.write(buffer)&#xA;&#xA;            f.close&#xA;            print path + file + &amp;quot;  OK&amp;quot;&#xA;            return response&#xA;&#xA;        except urllib2.HTTPError,e:&#xA;            print path + file + &amp;quot;  NG&amp;quot;&#xA;&#xA;&#xA;class LoginError(Exception):&#xA;    def __init__(self, e):&#xA;        Exception.__init__(self, e)&#xA;&#xA;if __name__ == '__main__':&#xA;    host = 'data.diasjp.net'&#xA;&#xA;    usage ='''usage: %prog [options]'''&#xA;    parser = optparse.OptionParser(usage=usage)&#xA;    parser.add_option('-n', '--netrc', default=None,&#xA;                      help='specify the netrc file', metavar='FILE')&#xA;    parser.add_option('-u', '--user', default=None,&#xA;                      help='specify the DIAS account name',&#xA;                      metavar='USERNAME')&#xA;&#xA;    (options, args) = parser.parse_args()&#xA;&#xA;    (login, password) = (None, None)&#xA;&#xA;    try:&#xA;      auth = netrc.netrc(options.netrc).authenticators(host)&#xA;      if auth is not None:&#xA;            (login, account, password) = auth&#xA;    except (IOError):&#xA;      pass&#xA;&#xA;    if options.user is not None:&#xA;        login = options.user&#xA;        password = None&#xA;&#xA;    if login is None:&#xA;        login = raw_input('Username: ')&#xA;&#xA;    if password is None:&#xA;        password = getpass.getpass('Password: ')&#xA;&#xA;    access = DIASAccess(login, password)&#xA;&#xA;&#xA;    targeturl='https://data.diasjp.net/dl/storages/filelist/dataset:645'&#xA;    response = access.open(targeturl)&#xA;    response.close()&#xA;&#xA;&#xA;    access.dl('https://data.diasjp.net/dl/storages/downloadCmd/L0pSQTNRL0NsaW05MTIwL0RhaWx5L2FubF9pc2VudHJvcC9hbmxfaXNlbnRyb3BfYnZmMi5jbGltOTEyMC5kYXkwMTAx', '/JRA3Q/Clim9120/Daily/anl_isentrop/', 'anl_isentrop_bvf2.clim9120.day0101')&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;and replace the parameters in &lt;code&gt;access.dl&lt;/code&gt; appropriately.&lt;/p&gt;&#xA;" OwnerUserId="14348" LastActivityDate="2023-08-15T21:12:33.807" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25507" PostTypeId="1" AcceptedAnswerId="25508" CreationDate="2023-08-15T22:29:15.540" Score="1" ViewCount="80" Body="&lt;p&gt;&lt;a href=&quot;https://economymiddleeast.com/news/new-delta-the-largest-in-the-history-of-egyptian-agricultural-projects/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Egypt is planning to create a new delta&lt;/a&gt; on the left of the old one by building an artificial river that redirects agricultural waste water into the desert. The water should gradually turn the desert into land that's suitable for agriculture. &lt;a href=&quot;https://youtu.be/Ogsfn1D6xJw?t=177&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here's a video&lt;/a&gt; that explains the plan further.&lt;/p&gt;&#xA;&lt;p&gt;This ambitious plan will cost around 9 billion euro's to complete. What I don't understand about it though is how simply redirecting water to a desert can turn it into arable land. The Egyptian desert consists of sandy soil and this soil type usually lacks the nutrients necessary for crops to grow. So how will this work?&lt;/p&gt;&#xA;" OwnerUserId="18140" LastEditorUserId="2470" LastEditDate="2023-08-16T04:09:48.070" LastActivityDate="2023-08-16T04:21:02.630" Title="How can an artificial river turn desert into arable land?" Tags="|agriculture|desert|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25508" PostTypeId="2" ParentId="25507" CreationDate="2023-08-16T04:21:02.630" Score="0" Body="&lt;p&gt;Such projects take time to fully achieve their aims. In addition to providing water, the sand will need to undergo a process of &lt;a href=&quot;https://en.wikipedia.org/wiki/Soil_conditioner&quot; rel=&quot;nofollow noreferrer&quot;&gt;soil conditioning&lt;/a&gt;. This will include the progressive addition of &lt;a href=&quot;https://en.wikipedia.org/wiki/Biomass&quot; rel=&quot;nofollow noreferrer&quot;&gt;biomass&lt;/a&gt;, &lt;a href=&quot;https://en.wikipedia.org/wiki/Humus&quot; rel=&quot;nofollow noreferrer&quot;&gt;humus&lt;/a&gt; and compost. This will include a means of water retention, which may include the application of clay or slit either mechanically or via the outflow of the Nile River.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-08-16T04:21:02.630" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25509" PostTypeId="1" CreationDate="2023-08-16T05:58:04.343" Score="0" ViewCount="105" Body="&lt;p&gt;Along the same geographic latitude does magnetic field change or not, and the same for the gravitational field, does it change along a geographic latitude?  Please explain.&lt;/p&gt;&#xA;" OwnerUserId="29447" LastEditorUserId="6298" LastEditDate="2023-08-16T06:21:35.820" LastActivityDate="2023-08-16T17:09:45.050" Title="Do gravity and magnetic field change along a geographic latitude or not?" Tags="|geophysics|geomagnetism|gravity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25510" PostTypeId="1" CreationDate="2023-08-16T14:05:58.077" Score="1" ViewCount="63" Body="&lt;p&gt;Many people have asked how high above the earth one must be to see the horizon curve, but I have yet to see a mathematical answer that correlates to the dimensions of the earth. As you rise above the earth the horizon continues to seem to be a circle around you, all in the same plane, with your eyes in the center and your line of sight the radius. But at some altitude suddenly your eyes seem to be above the center and you are looking down at the circle. At that point you see the curvature. Surely that magical altitude is some multiple of the earth’s radius, no?&lt;/p&gt;&#xA;" OwnerUserId="29481" LastActivityDate="2023-08-16T14:05:58.077" Title="Necessary Altitude to See Curvature of the Horizon" Tags="|geophysics|" AnswerCount="0" CommentCount="0" ClosedDate="2023-08-19T02:05:16.640" ContentLicense="CC BY-SA 4.0" />
  <row Id="25511" PostTypeId="2" ParentId="25509" CreationDate="2023-08-16T17:09:45.050" Score="4" Body="&lt;p&gt;They can both change along any direction.&lt;/p&gt;&#xA;&lt;p&gt;Here's Earth's magnetic field strength in early 2014, from &lt;a href=&quot;https://climate.nasa.gov/news/3105/earths-magnetosphere-protecting-our-planet-from-harmful-space-energy/&quot; rel=&quot;nofollow noreferrer&quot;&gt;ESA via NASA&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zwpgu.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zwpgu.jpg&quot; alt=&quot;Earth's magnetic field, early 2014&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;And here's Earth's gravitational field strength courtesy of &lt;a href=&quot;https://www.earthdata.nasa.gov/learn/sensing-our-planet/matter-in-motion-earths-changing-gravity&quot; rel=&quot;nofollow noreferrer&quot;&gt;NASA's GRACE satellite&lt;/a&gt;.  Note that the anomalies are quite exaggerated; the gravitational field is very close to uniform.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.earthdata.nasa.gov/s3fs-public/imported/matter_2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://www.earthdata.nasa.gov/s3fs-public/imported/matter_2.jpg&quot; alt=&quot;Earth's gravitational field strength&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26713" LastActivityDate="2023-08-16T17:09:45.050" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25512" PostTypeId="1" CreationDate="2023-08-18T17:50:17.013" Score="1" ViewCount="78" Body="&lt;p&gt;My name is Steve. My question concerns two days in a row we had recently. Both days reached up to the high 90s, sunny with no rain or clouds. On the first day, the temperature only got down to about 70 degrees during the night. But on the second day, which had the same daily weather and temperature, the temperature got down to 48 degrees during the night. What causes this difference? Hope that makes sense. Feel free to email me for clarity. Thanks for your time.&lt;/p&gt;&#xA;&lt;p&gt;Steve&lt;/p&gt;&#xA;" OwnerUserId="29485" LastActivityDate="2023-08-19T10:10:56.673" Title="What determines the outside temperature when the sun goes down?" Tags="|temperature|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25513" PostTypeId="2" ParentId="3100" CreationDate="2023-08-19T03:45:15.243" Score="0" Body="&lt;p&gt;Based purely on a theoretical 'joining of the dots' it's appears somewhat probable that the trajectory of the impact site recently located near Deniliquin NSW and the remaining buried core of the offending meteor, caused mass vocanic activity in a (unique to the continent) region, now located in the south east part of the Australian mainland (above Melbourne for a rough description: &lt;a href=&quot;https://www.australiangeographic.com.au/topics/science-environment/2016/05/australias-volcanic-history-is-a-lot-more-recent-than-you-think/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.australiangeographic.com.au/topics/science-environment/2016/05/australias-volcanic-history-is-a-lot-more-recent-than-you-think/&lt;/a&gt;, and I further believe due to continental drift, this impact may have also been the possible catalyst for the Great Dividing Range (approximate age circa around impact period or thereafter) Imagine a (tectonic) plate grinding over a 'massive' foreign body, for example.&lt;/p&gt;&#xA;&lt;p&gt;Something both large and deep enough to potentially create a hotspot beneath our tectonic plate. Would definitely cause an upward effect, with and without volcanic activity, due to related fracturing caused by such an imlact.&lt;/p&gt;&#xA;&lt;p&gt;Once again, this is a brief summary of my theory, and I'm very keen to hear anyone's feedback or thoughts.&lt;/p&gt;&#xA;" OwnerUserId="29488" LastActivityDate="2023-08-19T03:45:15.243" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25514" PostTypeId="2" ParentId="25512" CreationDate="2023-08-19T10:10:56.673" Score="4" Body="&lt;p&gt;In general, a number of factors can come into play, it depends on local circumstances:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Cloud cover&lt;/strong&gt; - clouds can act as an insulator and retain heat between them and the Earth's surface. Open skies allow heat to escape; particularly during the night.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;The presence or absence of cold fronts&lt;/strong&gt; - as their name suggests, cold fronts bring with them cooler weather conditions and sometimes rain and storms.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;The movement or non movement of high and low pressure system&lt;/strong&gt; - high pressure systems tend to produce calm conditions with uniform temperatures, whereas low pressure systems can be chaotic, bringing variable temperatures and conditions. The proximity of low and high pressure systems to each other and the pressure differences between the two can affect wind speeds and directions.&lt;/p&gt;&#xA;&lt;p&gt;Without any additional information in the question, in your situation I am guessing that during the first night, your location may have been influenced by a high pressure system. As it moved, air from a cooler region was brought in by the wind and cooled your location. Such cooler regions can be arctic regions or oceans, possibly even the great lakes of north America.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-08-19T10:10:56.673" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25515" PostTypeId="1" CreationDate="2023-08-20T18:08:39.060" Score="2" ViewCount="45" Body="&lt;p&gt;I'm trying to help a general audience understand some important climate numbers, starting with the fact that we're about 1.14°C warmer than pre-industrial.  Is it helpful context or misleading oversimplification to say:&lt;/p&gt;&#xA;&lt;p&gt;Global mean temperature at the peak of the last ice age was 4&amp;deg;C or 5&amp;deg;C cooler than pre-industrial, so we are about a quarter of the way toward a world that could be as different, but in the warmer direction, as when most of North America was glaciated.&#xA;&lt;p&gt;where 4&amp;deg;C is via https://climatefeedback.org/explainer-how-the-rise-and-fall-of-co2-levels-influenced-the-ice-ages/,&lt;br&gt;&#xA;4&amp;deg;C or maybe 5&amp;deg;C is via p42 at https://open.oregonstate.education/climatechange/open/download?type=pdf, and&lt;br&gt;&#xA;1.14&amp;deg;C is via page 4 of https://library.wmo.int/doc_num.php?explnum_id=11593&#xA;" OwnerUserId="29493" LastEditorUserId="29493" LastEditDate="2023-08-20T19:30:23.470" LastActivityDate="2023-08-20T19:30:23.470" Title="How to contextualize climate &quot;1.14C warmer than pre-industrial&quot; for a general audience" Tags="|climate|education|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25516" PostTypeId="1" CreationDate="2023-08-21T11:14:18.070" Score="0" ViewCount="17" Body="&lt;p&gt;I want to show cloud movements from satellite imagery.&lt;/p&gt;&#xA;&lt;p&gt;How does sites like ZoomEarth.com make cloud animations? My understanding is:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;They download images from satellite image providers.&lt;/li&gt;&#xA;&lt;li&gt;Play those images sequentially.&#xA;Is that correct?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;How is the night time imagery handled?&lt;/p&gt;&#xA;" OwnerUserId="29495" LastActivityDate="2023-08-21T11:14:18.070" Title="Showing cloud animations on a website" Tags="|clouds|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25517" PostTypeId="2" ParentId="25369" CreationDate="2023-08-21T14:35:30.550" Score="0" Body="&lt;p&gt;Tons of articles on tidal triggering of global earthquakes. Like this one:&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;A review of tidal triggering of global earthquakes&amp;quot;&#xA;August 2022 Geodesy and Geodynamics 14(1)&#xA;DOI:10.1016/j.geog.2022.06.005&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.researchgate.net/publication/362666022_A_review_of_tidal_triggering_of_global_earthquakes&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/publication/362666022_A_review_of_tidal_triggering_of_global_earthquakes&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;And subduction can't be density driven. The average density of old and new crust is the same cuz their average temperatures are the same. Older crust is not getting colder, it's getting thicker. They both have the same temperatures on their bottoms and tops, thus their average temperatures are the same.&lt;/p&gt;&#xA;&lt;p&gt;Edit:&#xA;Actually, on de-lamination, an older slab produces a layer of material of density higher than the average density of the slab. But that happens at the end of subduction and couldn't normally be considered as the driving force for subduction.&lt;/p&gt;&#xA;" OwnerUserId="1360" LastEditorUserId="1360" LastEditDate="2023-08-21T14:51:35.397" LastActivityDate="2023-08-21T14:51:35.397" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25521" PostTypeId="1" CreationDate="2023-08-24T21:08:16.727" Score="0" ViewCount="12" Body="&lt;p&gt;I thought it would be a 0/1 mask that would tell if each pixel is covered by cloud or not but instead it has integer values.&#xA;What do they represent?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rx4d3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rx4d3.png&quot; alt=&quot;values in a CLD file&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29511" LastActivityDate="2023-08-24T21:08:16.727" Title="What do the values in Cloud Mask represent in landcovernet database?" Tags="|open-data|database|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25523" PostTypeId="1" CreationDate="2023-08-25T08:52:09.703" Score="0" ViewCount="121" Body="&lt;p&gt;I have a question about which forces cause alignment of objects with the rotation of the Earth and how:&lt;/p&gt;&#xA;&lt;p&gt;It is known to me from public sources that objects up to a height of about 36,000 meters above the surface of the Earth move (if we ignore their own speed) completely in line with the surface of the Earth, because they are attracted by the Earth's core. When, for example, an airplane flies at an altitude of 10,000 m, it is not decisive for the earth's rotation whether it flies east or west, north or south.&lt;/p&gt;&#xA;&lt;p&gt;Furthermore, the speed of the Earth's rotation at the equator is approximately 1670 km/h, and the core of the earth - to which objects are said to be attracted, according to scientists, rotates differently - there are even theories that the other way around - than the earth's shell.&lt;/p&gt;&#xA;&lt;p&gt;That's what I've studied.&lt;/p&gt;&#xA;&lt;p&gt;And my question is - what forces, and how, cause the fact that an object at a height of up to 36,000 m is still attracted to the same place on the Earth's surface despite all the rotations, i.e. that it exactly copies the rotation of the Earth's surface when it is 36,000 m above it (or 10,000 m for a normal aircraft).&lt;/p&gt;&#xA;" OwnerUserId="29514" LastEditorUserId="543" LastEditDate="2023-09-26T20:49:27.773" LastActivityDate="2023-09-26T20:49:27.773" Title="Which forces align objects with the rotation of the Earth and how?" Tags="|gravity|orbit|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25524" PostTypeId="2" ParentId="13959" CreationDate="2023-08-25T09:19:22.730" Score="0" Body="&lt;p&gt;Jumping off of the first answers in hopes of answering OP in the most succinct fashion --&lt;/p&gt;&#xA;&lt;p&gt;Seen calculations that PETM was 12C warmer, or 22 degrees Fahrenheit warmer.  That is of course a global average.  Key to understanding such climactic conditions is the harmonization of temperatures (and humidity) between Equator and Poles.  The Poles were only few degrees cooler than Equator and the Equator only slightly warmer than today.  Ofc nothing stops the 6 month dark winters at pole, even if they were warm by today's standards.  Imagine swimming in Arctic Ocean with aurora borealis aka Northern Lights above you and all sort of night-jungle sounds!  (We'll ignore the bitey predators)&lt;/p&gt;&#xA;&lt;p&gt;With minimal thermal differences of pole and equator... less violent weather just sluggish winds due to earth's spin, (suppose lunar tug?) and inherent cooling of one pole being in darkness.&lt;/p&gt;&#xA;&lt;p&gt;No deserts at first, under Eocene conditions, but as ice caps grow they take rain out of circulation and ends up not enough to go around it seems so as time progresses cooler and drier.&lt;/p&gt;&#xA;&lt;p&gt;All manner of strange beasts, mammals and birds we'd not regognize except from maybe nightmares of collective unconscious.  Flesh eating kangaroos in the following Miocene of Australia, just to help direct your imagination:&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Also on the dig was Dr Sue Hand, a vertebrate palaeontologist. &amp;quot;This group of animals we affectionately call killer kangaroos,&amp;quot; she said. Their teeth, she added, were not for grazing. &amp;quot;These things had slicing crests that could have crunched through bone.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;It was rad in my book.&lt;/p&gt;&#xA;" OwnerUserId="29516" LastActivityDate="2023-08-25T09:19:22.730" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25525" PostTypeId="2" ParentId="25523" CreationDate="2023-08-27T01:16:57.170" Score="1" Body="&lt;p&gt;I think what you are referring to is a &lt;a href=&quot;https://en.wikipedia.org/wiki/Geostationary_orbit&quot; rel=&quot;nofollow noreferrer&quot;&gt;geostationary orbit&lt;/a&gt;, judging from your statement:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;is still attracted to the same place on the Earth's surface despite all the rotations&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;However, I think your distance is out by a factor of 1000: 36,000 km not 36,000 m.&lt;/p&gt;&#xA;&lt;p&gt;For an object to orbit the Earth and still be above a particular location on the Earth's surface, the object needs to be at least 36,000 above the Earth.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;An object in such an orbit has an orbital period equal to Earth's rotational period, one sidereal day, and so to ground observers it appears motionless, in a fixed position in the sky. The concept of a geostationary orbit was popularised by the science fiction writer Arthur C. Clarke in the 1940s as a way to revolutionise telecommunications&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Objects in such orbits are usually weather or communications satellites and sometimes spy satellites.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-08-27T01:16:57.170" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25526" PostTypeId="1" CreationDate="2023-08-27T01:18:21.180" Score="1" ViewCount="49" Body="&lt;p&gt;Below is my dataframe&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/OQJf3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/OQJf3.png&quot; alt=&quot;This is my dataframe&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I want to calculate the climatological monthly average, the total average for each month.&lt;/p&gt;&#xA;&lt;p&gt;For example, when I use groupby to estimate the monthly average of the variable AREA as below&lt;/p&gt;&#xA;&lt;p&gt;annual_average = df.groupby(by=[pd.Grouper(key='TIME', freq='M')])['AREA'].mean().reset_index()&lt;/p&gt;&#xA;&lt;p&gt;it gives me this below (weekly average for each month for each year):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/uk63v.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uk63v.png&quot; alt=&quot;Weekly average for each month&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I want to calculate the average for each month but over the years from 1981 to 2018&lt;/p&gt;&#xA;&lt;p&gt;Many thanks&lt;/p&gt;&#xA;" OwnerUserId="26675" LastEditorUserId="26675" LastEditDate="2023-08-27T02:49:39.587" LastActivityDate="2023-08-27T02:49:39.587" Title="How to calculate seasonal component from weekly data using dataframepython?" Tags="|python|data-analysis|climate-data|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25527" PostTypeId="1" CreationDate="2023-08-27T03:34:54.030" Score="3" ViewCount="69" Body="&lt;p&gt;Hello fellow oceanographers, I just trying to design a fourth-order low-pass butterworth filter with a 15-days cutoff period, in python, with the aim to filter a ocean bottom pressure (OBP) time series sampled every hour. This is my code:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import pandas as pd&#xA;import numpy as np&#xA;import scipy &#xA;from scipy.signal import butter, filtfilt, sosfiltfilt&#xA;&#xA;&#xA;&#xA;M = len(OBP['SPFO4']) # Number of points &#xA;# OBP['SPFO4'] is the OBP time series.&#xA;&#xA;# === Applying the tapering function&#xA;beta = 2&#xA;window = scipy.signal.windows.kaiser(M,beta,sym=True)&#xA;OBP['SPFO4'] = window * OBP['SPFO4']&#xA;&#xA;########### Applying the filter&#xA;&#xA;fs = 1 # Sampling frecuency (sampled every hour)&#xA;fc = 1/360 # 24(hours)*15(days) = 360 hours, &#xA; # Am I correct in this step ?&#xA;fc_norm = fc/(fs/2) &#xA;# Define the filter order (4th order is commonly used)&#xA;filter_order = 2 # I used 2 because it is a forward-backward filtering,&#xA;                 # so the input is mulplied by two ?&#xA;&#xA;# Generate the Butterworth filter coefficients&#xA;b, a = butter(filter_order, fc_norm, btype='lowpass',analog=False)&#xA;&#xA;OBP['SPFO4']= filtfilt(b, a,OBP['SPFO4'])&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;I have documented myself to build a code correctly in the sense of signal analysis, since I am new to this. So my concern is that&#xA;(1) if my code is well written for the purposes I need it to be?&#xA;(2) As you know, I am using signal.filtfilt(), but I have seen other option: signal.sosfiltfilt(). I am confused  because the two pictures obtained look a little different. Why?&lt;/p&gt;&#xA;&lt;p&gt;Anyone could help me to understand the previous questions and and what depends on using a certain order in a butterworth filter (I took the order from this article: &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020JB020065&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020JB020065&lt;/a&gt;, page 4, second paragraph)?&#xA;Any scientific article that explain this would be grateful. I attached the pictures.&lt;/p&gt;&#xA;&lt;p&gt;This is obtained using signal.filtfilt()&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WOvXf.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WOvXf.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is obtained using signal.sosfiltfilt()&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Og07D.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Og07D.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27360" LastEditorUserId="27360" LastEditDate="2023-08-28T21:38:26.237" LastActivityDate="2023-08-28T21:38:26.237" Title="A low-pass butterworth filter to analyze ocean bottom pressure" Tags="|oceanography|python|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25529" PostTypeId="1" CreationDate="2023-08-28T20:25:49.617" Score="1" ViewCount="195" Body="&lt;p&gt;Is there a way to know, how fast can water erode stone? I mean, if I just put a single stone and drip water on it 24/7, how soon will erosion become noticable?&lt;/p&gt;&#xA;&lt;p&gt;I've seen a video about &amp;quot;15,25 and 50 years of erosion&amp;quot;, but is there a way that the difference can be noticable in like a month or several months? Maybe there are stones which tend to be eroded faster than others?&lt;/p&gt;&#xA;" OwnerUserId="29527" LastActivityDate="2023-08-29T04:36:39.400" Title="How fast can water erode stone?" Tags="|geology|water|erosion|time|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25530" PostTypeId="2" ParentId="25527" CreationDate="2023-08-28T21:20:41.003" Score="1" Body="&lt;p&gt;I think your best bet is to use the filter that comes with scipy: &lt;a href=&quot;https://docs.scipy.org/doc/scipy/reference/generated/scipy.signal.butter.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://docs.scipy.org/doc/scipy/reference/generated/scipy.signal.butter.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;from scipy import signal&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;import numpy as np&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;b, a = signal.butter(4, 100, 'low', analog=True)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="111" LastActivityDate="2023-08-28T21:20:41.003" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25531" PostTypeId="1" CreationDate="2023-08-28T21:40:05.167" Score="2" ViewCount="37" Body="&lt;p&gt;I don't understand the difference between radiative forcing and an energy budget. They seem like the same concept to me but I cannot find anything that directly compares them.&lt;/p&gt;&#xA;" OwnerUserId="29528" LastActivityDate="2023-08-28T21:40:05.167" Title="What is the difference between Radiative Forcing and Energy Budget" Tags="|atmospheric-radiation|radiation-balance|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25533" PostTypeId="2" ParentId="25529" CreationDate="2023-08-29T04:36:39.400" Score="2" Body="&lt;p&gt;In short, it depends on the type of stone, the energy of impact of the water and for how long water is applied with such an energy of impact.&lt;/p&gt;&#xA;&lt;p&gt;A weak stone such as sandstone will erode more quickly than basalt or obsidian. The hardness of the stone and the strength of the bonds between minerals comprising the stone will contribute to the stone's wear and erosion resistance; particularly hardness. The more obdurate a mineral the greater its resistance to wear and erosion. This is seen in nature, where softer minerals are eroded preferentially before hard minerals, whether the erosion be by water or wind.&lt;/p&gt;&#xA;&lt;p&gt;The average erosion rate for each type of stone needs to be determined from experimentation.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-08-29T04:36:39.400" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25534" PostTypeId="2" ParentId="25447" CreationDate="2023-08-29T08:46:11.480" Score="2" Body="&lt;p&gt;Essentially, its bad news for Europe and North America (and the rest of the world).&lt;/p&gt;&#xA;&lt;p&gt;The AMOC transports warm water from the equator up towards the North pole and cold waters from the north pole towards the equator. This is an important factor in regulating the climate of North America and Europe.&lt;/p&gt;&#xA;&lt;p&gt;Its very difficult to say exactly when or what will happen (we need more data) but its likely that when/if the AMOC collapses the northern hemisphere will go into an ice age. An AMOC collapse will also result in increased drought in some areas while others will have increased flooding. This will result in more disease and mass migrations of animals.&lt;/p&gt;&#xA;&lt;p&gt;Here is a reliable source: &lt;a href=&quot;https://www.whoi.edu/oceanus/feature/whats-happening-with-the-amoc/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.whoi.edu/oceanus/feature/whats-happening-with-the-amoc/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12663" LastEditorUserId="12663" LastEditDate="2024-01-30T11:24:29.107" LastActivityDate="2024-01-30T11:24:29.107" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25536" PostTypeId="1" CreationDate="2023-08-30T13:43:59.810" Score="3" ViewCount="108" Body="&lt;p&gt;I mean a part of a country that can't be reach from the rest without leaving the country or it's territorial water.&lt;/p&gt;&#xA;&lt;p&gt;I don't know if exclave really covers what I'm thinking of. For example would the Azores be called an exclave of Portugal?&lt;/p&gt;&#xA;" OwnerUserId="29547" LastActivityDate="2023-11-06T12:52:52.837" Title="Is there a term for part of a country separated from the rest in general" Tags="|geography|terminology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25537" PostTypeId="1" CreationDate="2023-08-30T15:36:09.710" Score="0" ViewCount="49" Body="&lt;p&gt;Todays Biue Moon (that wont happen again til 2036)  is the biggest brightest and closest the moon is to Earth&#xA;Im trying to determine how it appears at ones given latitude.Obviously the closest one is to the equator the larger and brighter it should appear. I asked  Google but could not find a formula to determine the thickness of the Earth by horizontal cross section at a given latitude. Those  show the distance from a given latitude to the Earths center as clearly indicated by their nearly uniform measurement whether from the equator or the poles!&lt;/p&gt;&#xA;" OwnerUserId="29548" LastActivityDate="2023-09-03T10:12:51.477" Title="Im trying to find a formula to calculate Earths radius/ diameter by horizontal cross section to see what effect that has on size of the moon appears" Tags="|earth-observation|moon|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25538" PostTypeId="1" CreationDate="2023-08-30T16:29:27.407" Score="1" ViewCount="55" Body="&lt;p&gt;Firstly, a REGO is a &lt;a href=&quot;https://www.ofgem.gov.uk/environmental-and-social-schemes/renewable-energy-guarantees-origin-rego/renewable-energy-guarantees-origin-rego-electricity-suppliers-and-generators&quot; rel=&quot;nofollow noreferrer&quot;&gt;Renewable Energy Guarantee of Origin&lt;/a&gt;. We have these in the UK, and they are probably quite self-explanatory: a windfarm (for example) generates a certain amount of kWh which are then pumped into the UK Grid. This then gives them a certificate stating that x kWh of sustainable energy have been contributed. They can sell these certificates to anyone interested in buying them. In your country you may have a different mechanism, or just a different name: I have no idea.&lt;/p&gt;&#xA;&lt;p&gt;Secondly, I'm slightly shocked that this appears to be best fit in terms of Stack Exchange forums: I'd have expected one dedicated to Climate Change, or maybe the environment ...&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;In the UK there is a lot of talk about &amp;quot;greenwashing&amp;quot; when it comes to the supply of electricity, and in fact there has been for quite a long time. The supplier I'm with, which has generally one of the better reps, claims that it is supplying &amp;quot;100% green&amp;quot; electricity to my house. But in fact it buys lots of electricity generated from hydrocarbons. It is allowed to claim &amp;quot;100% green&amp;quot; because it also buys these REGOs.&lt;/p&gt;&#xA;&lt;p&gt;Unless I have misunderstood, REGOs are a way of, if not &amp;quot;overcoming&amp;quot; this problem, at least trying to neutralise it. I have read &lt;a href=&quot;https://www.ecotricity.co.uk/our-green-energy/greenwashing&quot; rel=&quot;nofollow noreferrer&quot;&gt;this Ecotricity page&lt;/a&gt; on the subject, and I still don't understand. In particular I don't understand why REGOs are (said to be) so cheap.&lt;/p&gt;&#xA;&lt;p&gt;Is the key to understanding this issue that there are vast numbers of consumers (perhaps not just domestic consumers) who couldn't care less what kind of source their energy is coming from? Otherwise, wouldn't each precious kWh from sustainable sources be carefully bought by the various consumers (of all kinds) up and down the UK? How come vast amounts of REGOs are being produced (e.g. by a given windfarm somewhere) and are nevertheless cheap as chips, in 2023?&lt;/p&gt;&#xA;&lt;p&gt;NB I've also got the impression that there's an international dimension to this which may make things even more impenetrable.&lt;/p&gt;&#xA;&lt;p&gt;If my description of this situation is anything like close to the truth, this would imply that the reasoning behind &amp;quot;Level 3&amp;quot; on the Ecotricity page is puzzingly disingenuous. In the sense that it's a diversion to imagine that suppliers MUST generate their own electricity. In reality, if all consumers across the board were demanding electricity from sustainable sources, the price of REGOs would rise and create demand for construction of new renewable capacity. So the real question would then be: who are these consumers who are unconcerned about sustainable electricity?&lt;/p&gt;&#xA;&lt;p&gt;If you speak from a position of knowledge about these matters I'd be happy to hear any explanations.&lt;/p&gt;&#xA;" OwnerUserId="18505" LastEditorUserId="18505" LastEditDate="2023-08-30T18:06:27.213" LastActivityDate="2023-08-30T18:06:27.213" Title="Why are REGOs are so bad?" Tags="|climate-change|energy|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25539" PostTypeId="1" AcceptedAnswerId="25540" CreationDate="2023-08-30T17:30:39.167" Score="1" ViewCount="366" Body="&lt;p&gt;I am looking for a reference (e.g. book, peer-reviewed paper) that asserts that&#xA;absolute humidity is &amp;quot;equivalent&amp;quot; to the dew-point temperature.&lt;/p&gt;&#xA;&lt;p&gt;Such statement should be true, AFAIU. Online, &lt;a href=&quot;https://www.quora.com/Why-is-the-dew-point-a-consequence-of-the-absolute-humidity&quot; rel=&quot;nofollow noreferrer&quot;&gt;people say&lt;/a&gt; &lt;a href=&quot;https://www.memphisweather.blog/2013/08/how-humid-is-it-why-dew-point-is.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;they are the same&lt;/a&gt;, in scientific publications they look almost linearly related in some range of temperatures &lt;a href=&quot;https://www.naun.org/main/NAUN/mechanics/19-574.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here, figure 4&lt;/a&gt;, I tested their relation on data I have and their correlation is &lt;span class=&quot;math-container&quot;&gt;$ &amp;gt; 0.98$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;But I am unable to find a reference that states the absolute humidity and the dew-point temperature are &amp;quot;equivalent&amp;quot;, &amp;quot;highly correlated (under reasonable conditions)&amp;quot;, or that &amp;quot;one can serve as a proxy for the other&amp;quot;. Please help me find such reference.&lt;/p&gt;&#xA;" OwnerUserId="29551" LastActivityDate="2023-08-30T18:23:11.030" Title="Dew-point temperature and absolute humidity" Tags="|meteorology|temperature|humidity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25540" PostTypeId="2" ParentId="25539" CreationDate="2023-08-30T18:23:11.030" Score="1" Body="&lt;p&gt;They're not directly equivalent.  I think the problem is that &amp;quot;absolute humidity&amp;quot; is used to mean both &amp;quot;a measurement of the actual humidity content of the air&amp;quot; (&amp;quot;absolute&amp;quot; as in &amp;quot;non-relative&amp;quot;) and, in some sources, &amp;quot;mass of water vapor per unit volume&amp;quot; - which is temperature-dependent as well (using &lt;span class=&quot;math-container&quot;&gt;$PV=nRT$&lt;/span&gt; at fixed pressure and mass: &lt;span class=&quot;math-container&quot;&gt;$V$&lt;/span&gt; varies with &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt;).&lt;/p&gt;&#xA;&lt;p&gt;I think this &lt;a href=&quot;https://www.nasa.gov/centers/dryden/pdf/87878main_H-937.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;technical note&lt;/a&gt; covers it.  Key points:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Vapor pressure is a function of dew point alone (Eq. 16 - remaining variables are constants).&lt;/li&gt;&#xA;&lt;li&gt;Absolute humidity is a function of vapor pressure &lt;em&gt;and temperature&lt;/em&gt; (Eq. 3).&lt;/li&gt;&#xA;&lt;li&gt;Thus, absolute humidity is a function of both dew point and temperature (Eq. 20).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The reason they appear to be directly related, like in the dataset you looked at, is that &lt;span class=&quot;math-container&quot;&gt;$T$&lt;/span&gt; (in Kelvin) only varies by 20% or so in a typical temperature range (e.g., -20 to +40 C = 253 to 313 K), so it doesn't affect things that much.&lt;/p&gt;&#xA;&lt;p&gt;That technical note does work as a citation for dew point being an absolute measurement of humidity, since it corresponds directly to vapor pressure in Eq. 16.&lt;/p&gt;&#xA;" OwnerUserId="26713" LastActivityDate="2023-08-30T18:23:11.030" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25541" PostTypeId="1" AcceptedAnswerId="25551" CreationDate="2023-08-31T02:59:28.063" Score="1" ViewCount="215" Body="&lt;p&gt;I used to talk with a family friend who often sent me links to Nobel Prize winners, claiming that climate change is a myth.&lt;/p&gt;&#xA;&lt;p&gt;Last week, we had a disagreement over a link referencing a Nobel Prize recipient (I believe it was Dr. John Clauser). This link displayed a graph of CO&lt;sub&gt;2&lt;/sub&gt; levels spanning the past 140 million years, indicating a linear decreasing trend. The article posited that we are depleting our CO&lt;sub&gt;2&lt;/sub&gt; reserves, a vital gas for plants and, by extension, the biosphere.&lt;/p&gt;&#xA;&lt;p&gt;I responded by saying:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;Jorge, that graph is misleading. CO&lt;sub&gt;2&lt;/sub&gt; levels during the&#xA;Phanerozoic era are influenced by the Wilson Cycle, and they correlate&#xA;with the formation and fragmentation of Pangaea. We are not depleting&#xA;CO&lt;sub&gt;2&lt;/sub&gt; as the subduction process is initiating in the&#xA;Atlantic. In the forthcoming million years, CO&lt;sub&gt;2&lt;/sub&gt; stored by&#xA;organisms will be released.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9l4vO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9l4vO.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;Source: Wikimedia Commons.&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;I heard this argument at the University of Zaragoza. However, I am uncertain if both my teacher and I have a comprehensive understanding of this matter. One of my concerns is that CO&lt;sub&gt;2&lt;/sub&gt; dissolves below the Calcite Compensation Depth. I'm unsure if all sediments dissolve or just the top layers. This uncertainty leaves me pondering whether my argument could be refuted on this basis. I couldn't find any clarifications on Science Direct either.&lt;/p&gt;&#xA;&lt;p&gt;Could someone elucidate this matter for both my friend (who will read this) and me?&lt;/p&gt;&#xA;&lt;p&gt;Are the Phanerozoic CO&lt;sub&gt;2&lt;/sub&gt; levels indeed linked with the Wilson Cycle? If so, why?&lt;/p&gt;&#xA;&lt;p&gt;Bonus Question:&lt;/p&gt;&#xA;&lt;p&gt;If humans wouldn't exist, would we run out of CO&lt;sub&gt;2&lt;/sub&gt;? (To me, this seems like an absurd query, especially in the context of that Nobel Prize article, because we'll likely gain control over Earth's geochemistry and climate long before then.) To rephrase: if we exclude human influence, would shell organisms eventually consume all the CO&lt;sub&gt;2&lt;/sub&gt; by the end of the Phanerozoic era, leading to a mass extinction and the emergence of a distinct form of life? Would this scenario transpire in this cycle or the next?&lt;/p&gt;&#xA;" OwnerDisplayName="user29526" LastEditorDisplayName="user29526" LastEditDate="2023-09-01T23:11:04.193" LastActivityDate="2023-10-07T00:22:03.430" Title="Interpretation of Phanerozoic CO2 levels graph" Tags="|geochemistry|earth-history|co2|carbon-cycle|" AnswerCount="1" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25544" PostTypeId="1" CreationDate="2023-09-02T14:54:38.090" Score="2" ViewCount="55" Body="&lt;p&gt;Water vapor is the most significant greenhouse gas in the Earth's atmosphere. However, tropospheric water vapor has a short atmospheric half-life. Therefore, anthropogenic surface-level water vapor emissions are generally not considered to significantly contribute to climate change.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, stratospheric water vapor has a much longer half-life. Anthropogenic emission sources of stratospheric water include exhaust gases from aviation. What is the current scientific understanding of the significance of these emissions? How much do they contribute compared to other anthropogenic greenhouse gas emissions? How much do they contribute compared to CO&lt;sub&gt;2&lt;/sub&gt; emissions from aviation? Is the contribution different on shorter and longer timescales?&lt;/p&gt;&#xA;" OwnerUserId="29564" LastEditorUserId="2470" LastEditDate="2023-09-03T07:11:47.127" LastActivityDate="2023-09-03T07:11:47.127" Title="What is the role of stratospheric water vapor emissions in climate change?" Tags="|climate-change|atmosphere|water-vapour|stratosphere|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25546" PostTypeId="2" ParentId="14070" CreationDate="2023-09-03T07:10:34.477" Score="1" Body="&lt;p&gt;Looking the diagram you supplied in the question, at the bottom there is graphical representation of a cross section through a volcano. The structure in red represents the magma conduits. Magma is simply molten rock that has not reached the surface, when it does, it no longer is called magma, but lava.&lt;/p&gt;&#xA;&lt;p&gt;During a volcanic eruption, magma within the conduits is under pressure and it exerts pressure on the walls of the conduit - as can be explained by fluid mechanics.&lt;/p&gt;&#xA;&lt;p&gt;Where there is a weakness in the wall of the conduit pressurized magma exits the conduit. If the pressure of the magma is large enough, the release of magma can itself be forceful. If the overlying rock is doesn't have the strength and/or flexibility to contain the contain the injected magma the overlying rock can form a fissure through which magma can erupt on the surface as lava. Hence, such occurrences are called lava fissures.&lt;/p&gt;&#xA;&lt;p&gt;Something similar happens anatomically when arteries become weakened and can no longer withstand the pressure of blood within them and an artery ruptures, as occurs with ruptured aortas.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-09-03T07:10:34.477" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25547" PostTypeId="1" CreationDate="2023-09-03T09:53:30.210" Score="2" ViewCount="88" Body="&lt;p&gt;From the Wikipedia article for &lt;a href=&quot;https://en.m.wikipedia.org/wiki/Khone_Phapheng_Falls&quot; rel=&quot;nofollow noreferrer&quot;&gt;Khone Phapheng Falls&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;It is the widest waterfall in the world at &lt;span class=&quot;math-container&quot;&gt;$10783$&lt;/span&gt; metres (&lt;span class=&quot;math-container&quot;&gt;$35376$&lt;/span&gt; feet or &lt;span class=&quot;math-container&quot;&gt;$6.7$&lt;/span&gt; miles) in width from one edge of its multiple channels to the other.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;But on Google Maps the longest distance I measure is only &lt;span class=&quot;math-container&quot;&gt;$0.3$&lt;/span&gt; miles. Why is it incorrect?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/b7s0t.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/b7s0t.jpg&quot; alt=&quot;Khone&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/uk72E.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uk72E.jpg&quot; alt=&quot;Khone2&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29082" LastActivityDate="2023-09-05T17:51:09.863" Title="Why can't I measure the width of a waterfall on Google Maps?" Tags="|measurements|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25548" PostTypeId="2" ParentId="25537" CreationDate="2023-09-03T10:12:51.477" Score="-1" Body="&lt;p&gt;Method 1:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/thumb/7/72/Sinus_und_Kosinus_am_Einheitskreis_1.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://upload.wikimedia.org/wikipedia/commons/thumb/7/72/Sinus_und_Kosinus_am_Einheitskreis_1.svg&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;You know the Radius of the earth and the lattitude kindof, you can convert the lattitude using Sin or Cos function.&lt;/p&gt;&#xA;&lt;p&gt;Method 2:&lt;/p&gt;&#xA;&lt;p&gt;Rhumb line tool online, because parallels are rhumb lines:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.madinstro.net/sundry/navigation/rhumb_line.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.madinstro.net/sundry/navigation/rhumb_line.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;if you have a 1/2 or a full rhumb circle of a parallel using the GSM ellipsoid/spheroid, then you just need to know the radius.&lt;/p&gt;&#xA;" OwnerUserId="3315" LastActivityDate="2023-09-03T10:12:51.477" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25550" PostTypeId="2" ParentId="17697" CreationDate="2023-09-04T16:22:56.770" Score="1" Body="&lt;p&gt;Interesting question. I made a quick analysis based on &lt;a href=&quot;https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-era5-single-levels&quot; rel=&quot;nofollow noreferrer&quot;&gt;ERA5&lt;/a&gt; climate reanalysis. The maps below show the absolute maximum air temperature at 2 m height above ground (or simply air temperature), derived from latest 29 years (period 1994-2022). You find clear indication of the hottest regions.&lt;/p&gt;&#xA;&lt;p&gt;Global map of the absolute maximum air temperature&#xA;&lt;a href=&quot;https://i.stack.imgur.com/tk68D.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tk68D.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The same map with the focus on the regions with highest documented air temperature&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Tvnax.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Tvnax.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Note, that (of course) measured data by meteorological station locally can (slightly) differ from modeled ERA5 data.&lt;/p&gt;&#xA;" OwnerUserId="28538" LastActivityDate="2023-09-04T16:22:56.770" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25551" PostTypeId="2" ParentId="25541" CreationDate="2023-09-04T16:40:01.510" Score="0" Body="&lt;p&gt;On geological timescales, yes, the Wilson cycle (opening and closing of ocean basins) is bound to have an effect on atmospheric CO2 levels, if only because it will affect rainfall patterns, which in turn will affect chemical weathering of rocks, which is one of the things that removes CO2 from the air on very long timescales.&lt;/p&gt;&#xA;&lt;p&gt;This obviously doesn't explain the post-industrial rise in atmospheric CO2 though, which has occurred on the scale of a century or so, rather than tens to hundreds of millions of years.  So it seems like a grain of truth, but the argument is a non-sequitur.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;In the forthcoming million years, CO2 stored by organisms will be&#xA;released.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Citation required.&lt;/p&gt;&#xA;&lt;p&gt;As well as weathering (which is regarded as a thermostat that has been regulating planetary temperatures - see &amp;quot;The Global Carbon Cycle&amp;quot; by David Archer, Princeton University Press), they have also failed to mention that the sun's brightness has decreased (as it is a main sequence star) by about 6% over that timescale.  CO2 and temperature are part of a feedback loop, so the gradual dimming of the sun may be expected to reduce the amount of CO2 in the atmosphere, all things being otherwise equal.  It also ignores the evolution of land plants, and refinement of their photosynthetic machinery.&lt;/p&gt;&#xA;&lt;p&gt;So while it is reasonable to expect some linkage with the Wilson cycle, the claim seems to be highlighting only a cyclic component while ignoring other factors, without giving evidence of their relative importance.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;if we exclude human influence, would shell organisms eventually consume all the CO2 by the end of the Phanerozoic era&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;I very much doubt it, for a start CO2 is constantly being cycled from the sea floor via subduction and released by volcanos on the crust above.  This is an ongoing process.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Would this scenario transpire in this cycle or the next?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;It hasn't been established that there IS a cycle, rather than the combination of the effects of multiple factors affecting CO2 levels on geological timescales.  It is very easy to look at a graph and see something that looks like a cycle, what you need to demonstrate it is not spurious is some physics that explains not only the cycle but the magnitude of the effect.&lt;/p&gt;&#xA;" OwnerUserId="624" LastActivityDate="2023-09-04T16:40:01.510" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25552" PostTypeId="1" CreationDate="2023-09-04T19:51:14.153" Score="3" ViewCount="45" Body="&lt;p&gt;Why is so much of the literature I run across regarding global warming concerned with precipitating &lt;span class=&quot;math-container&quot;&gt;$\ce{CaCO3}$&lt;/span&gt; to the ocean floor?&lt;/p&gt;&#xA;&lt;p&gt;In areas of relatively lower pH, such as the eastern equatorial Pacific:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.nature.com/articles/s41598-019-55039-4&quot; rel=&quot;nofollow noreferrer&quot;&gt;Surface ocean pH and buffer capacity: past, present and future&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/f0fJo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/f0fJo.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Would not Ekman transport driven upwelling of &lt;span class=&quot;math-container&quot;&gt;$\ce{Ca+}$&lt;/span&gt; ions that remain in solution (due to the extreme depth and cold of the ocean floor in that area) reduce the surface &lt;span class=&quot;math-container&quot;&gt;$\ce{pCO2}$&lt;/span&gt;, hence reduce &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; transport to the atmosphere?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2bELJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2bELJ.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Indeed, if anything, it seems geoengineering proposals to reduce atmospheric &lt;span class=&quot;math-container&quot;&gt;$\ce{CO2}$&lt;/span&gt; should be considering exposure of &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonate_platform#Platforms_produced_by_the_%22tropical_factory%22&quot; rel=&quot;nofollow noreferrer&quot;&gt;eastern equatorial Pacific benthic carbonate platforms&lt;/a&gt; to dissolution in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonate_compensation_depth&quot; rel=&quot;nofollow noreferrer&quot;&gt;carbonate compensation depth&lt;/a&gt; (CCD) (i.e., below &lt;a href=&quot;https://en.wikipedia.org/wiki/Lysocline&quot; rel=&quot;nofollow noreferrer&quot;&gt;the lysocline&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/NLCV4.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/NLCV4.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22441" LastEditorUserId="6129" LastEditDate="2023-09-06T00:48:24.447" LastActivityDate="2023-09-06T00:48:24.447" Title="Since the upwelling of calcium carbonate reduces surface pCO2, why is its dissolution in the CCD below the lysocline of concern?" Tags="|climate-change|ocean-currents|carbon-cycle|ocean-models|carbonate|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25553" PostTypeId="2" ParentId="25547" CreationDate="2023-09-05T17:51:09.863" Score="2" Body="&lt;p&gt;Here's another view illustrating what is said above:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/szOsl.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/szOsl.jpg&quot; alt=&quot;Khone Phapheng Waterfall&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11587" LastActivityDate="2023-09-05T17:51:09.863" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25554" PostTypeId="1" CreationDate="2023-09-06T10:44:46.223" Score="0" ViewCount="86" Body="&lt;p&gt;In a &lt;a href=&quot;https://earthscience.stackexchange.com/questions/25547/why-cant-i-measure-the-width-of-a-waterfall-on-google-maps/25553#25553&quot;&gt;previous&lt;/a&gt; question I asked why I can't measure the width of Khone Phapheng Falls; and I found out from the comments that I didn't take this into account that Khone Phapheng Falls are sets of falls that all discharge water to the Mekong River.&lt;/p&gt;&#xA;&lt;p&gt;Now I have another question about the same falls:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JQDlH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JQDlH.jpg&quot; alt=&quot;Khone&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I found the westernmost fall of the system to be Sopheakmit Fall and Khone Phahpheng itself being the easternmost fall. I measured their distance and it turned out to be &lt;span class=&quot;math-container&quot;&gt;$6.7$&lt;/span&gt; miles which equals to &lt;span class=&quot;math-container&quot;&gt;$10783$&lt;/span&gt; meters that is reported as the width of the system of falls.&lt;/p&gt;&#xA;&lt;p&gt;But is it okay to measure the width of falls in this way? I mean even the rocks are included here! Shouldn't we just measure the width of each fall and then sum the numbers up to find the total width of the system?&lt;/p&gt;&#xA;&lt;p&gt;In the latter way the width is measured very less and it would be Victoria Falls that becomes the widest falls in the world instead of Khone Phapheng.&lt;/p&gt;&#xA;&lt;p&gt;Also, look at this picture which is from the answer on my previous question about the same falls:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/V2oiR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/V2oiR.jpg&quot; alt=&quot;Khone&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is the complete system of falls in the Khone Phapheng. But as I said before the &lt;span class=&quot;math-container&quot;&gt;$10783$&lt;/span&gt; meters width is from one edge of the easternmost fall to the edge of the wesrernmost fall and it includes the rocks between them. So is 10783 meters a correct number? Shouldn't we calculate the width of the system by summing up the widths of all falls?&lt;/p&gt;&#xA;" OwnerUserId="29082" LastEditorUserId="29082" LastEditDate="2023-10-11T13:53:30.857" LastActivityDate="2023-10-11T13:53:30.857" Title="Another question about the width of Khone Phapheng falls" Tags="|measurements|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25555" PostTypeId="2" ParentId="25227" CreationDate="2023-09-08T17:58:49.203" Score="0" Body="&lt;p&gt;The abstract of the paper says it is based on the assumption absorption bands are not saturated.  This is true only at low levels of CO2, much lower than at present.  See NASA Technical Memorandum 103957, Appendix E, which shows that zero IR energy gets to space in the 14-16micron band.  That is, the band is salready saturated&lt;/p&gt;&#xA;" OwnerUserId="29595" LastActivityDate="2023-09-08T17:58:49.203" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25561" PostTypeId="1" CreationDate="2023-09-11T08:34:06.160" Score="2" ViewCount="113" Body="&lt;p&gt;For reasons unknown, I started pondering what cities/towns in Sweden and Australia are the closest to each other. My hunch was that some town in the South such as Malmö or Karlskrona would be closest to some town in the North(west) of Australia such as Broome.&lt;/p&gt;&#xA;&lt;p&gt;Exploring the matter using &lt;a href=&quot;https://www.greatcirclemap.com/?routes=PJA-DRW%2C%20PER-MMX%2C%20BME-ARN%2C%20DRW-ARN%2C%20VBY-DRW&quot; rel=&quot;nofollow noreferrer&quot;&gt;greatcirclemap.com&lt;/a&gt; told me a different story - the closest town (airport) I could find was Pajala in the very North(east), which is closer to Darwin in the middle of the Australian North than to towns like Broome in the Northwest or Perth in the far West.&lt;/p&gt;&#xA;&lt;p&gt;Is there a simple, intuitive explanation for this fact? What is a good way to make educated guesses about great circle distances? How can Pajala be closer to Australia than Malmö, being about 1350 kilometers farther north but only 350 kilometers farther east?&lt;/p&gt;&#xA;" OwnerUserId="13314" LastActivityDate="2023-09-21T23:57:10.373" Title="Is there a way to intuitively explain that the North of Sweden is closer to Australia than the South?" Tags="|geodesy|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25562" PostTypeId="1" CreationDate="2023-09-11T19:16:27.793" Score="2" ViewCount="38" Body="&lt;p&gt;I have the &lt;em&gt;Soil Size Distribution Diagram&lt;/em&gt; shown below from a source that does not specify the meaning of the labels A1=60, A2=50, and A3=50. I understand that it is data for three different samples, but what do the numbers (60, 50, 50) indicates?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Yp5GH.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Yp5GH.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The diagram is constructed following a standard protocol where soil is collected, washed, dried, and sieved.&lt;/p&gt;&#xA;&lt;p&gt;If anyone can shed some light on the meaning of the labels A1=60, A2=50, and A3=50, it would be most helpful.&lt;/p&gt;&#xA;" OwnerUserId="29613" LastActivityDate="2023-09-11T19:16:27.793" Title="Reading a Soil Size Distribution Diagram" Tags="|soil|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25563" PostTypeId="1" CreationDate="2023-09-13T10:15:04.563" Score="1" ViewCount="54" Body="&lt;p&gt;This morning I took this picture pointing East, just before Sun rise (also the Moon and Venus are visible there): there's a tilted blue vertical ray amidst the golden horizon: I suppose this can be a crepuscular ray passing through a not yet visible cloud, but I'm wondering if this can be another phenomenon...&lt;/p&gt;&#xA;&lt;p&gt;Unfortunately I could not wait to see if there was a cloud with the Sun when it rose. What I can say is that there were no clouds visible in the sky at that moment.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/BUmmZ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BUmmZ.jpg&quot; alt=&quot;possible crepuscular ray, pointing East before Sun rise&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29620" LastActivityDate="2023-09-13T10:15:04.563" Title="name of this atmospheric phenomenon: possible crepuscular ray?" Tags="|sun|atmospheric-optics|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25564" PostTypeId="1" CreationDate="2023-09-15T05:59:44.957" Score="0" ViewCount="107" Body="&lt;p&gt;I have a netCDF file of stream function (psi) having dimension (latitude, level), level is pressure level. There are 5 pressure levels (700,600,500,400,300 hPa). I need to compute the mass weighted vertical average, i.e. before averaging I need to know the atmospheric mass at each pressure level which will be their weights and after that, average of psi will be computed. The final output will be one dimensional i.e. (latitude,). How to compute this weight and how to do it in Python?&lt;/p&gt;&#xA;" OwnerUserId="29632" LastEditorUserId="2470" LastEditDate="2023-09-17T06:05:53.377" LastActivityDate="2023-09-17T06:05:53.377" Title="Mass weighted vertical average of stream function in python" Tags="|meteorology|python|pressure|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25565" PostTypeId="1" AcceptedAnswerId="25566" CreationDate="2023-09-15T16:01:51.050" Score="4" ViewCount="343" Body="&lt;p&gt;I have watched storm Daniel on the internet while it was in Greece and what I saw was much heavier rain than what came down in Libya.  But in Libya, property damage and death toll were much heavier, with half a city washed away.  I don't understand why.&lt;/p&gt;&#xA;&lt;p&gt;Was there much more rainfall than reported on the internet?&lt;/p&gt;&#xA;&lt;p&gt;Or was the average rainfall correctly reported but unevenly distributed?&lt;/p&gt;&#xA;&lt;p&gt;Or did the landscape accumulate the water in a way that two dams could be broken so that all the water started to flow all at once?&lt;/p&gt;&#xA;" OwnerUserId="29637" LastEditorUserId="543" LastEditDate="2023-09-15T21:58:41.423" LastActivityDate="2023-09-25T23:22:08.310" Title="Why was the flooding in Derna, Libya so catastrophic?" Tags="|meteorology|hydrogeology|flooding|dams|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25566" PostTypeId="2" ParentId="25565" CreationDate="2023-09-16T08:09:11.137" Score="6" Body="&lt;p&gt;I hesitate to write this answer as I am neither a metereologist, nor a hydrologist, nor a civil engineer with expertise in dams.&lt;/p&gt;&#xA;&lt;p&gt;From what I gather from news reports and available data, the proximate cause of the Derna disaster was a flash flood of unprecedented magnitude, exacerbated by the failure of two flood-control dams.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Derna,_Libya&quot; rel=&quot;noreferrer&quot;&gt;Derna&lt;/a&gt; is a port city of some 90K-100K inhabitants on the Mediterranean coast of Libya, thus located almost at sea level. An intermittent river bed, Wadi Derna, bisects the city. According to &lt;a href=&quot;https://en.wikipedia.org/wiki/Wadi_Derna&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia&lt;/a&gt;, Wadi Derna has a length of about 75km and a drainage basin of about 575 km&lt;sup&gt;2&lt;/sup&gt;, with most of that area extending &lt;em&gt;west&lt;/em&gt; of the city, with the westernmost reaches about 25km east of Al-Bayda, at an elevation of about 600m according to Google Maps' terrain view. Based on the satellite view of Google Maps, the landscape is arid and rocky and almost completely devoid of vegetation.&lt;/p&gt;&#xA;&lt;p&gt;The World Meteorological Organization &lt;a href=&quot;https://public.wmo.int/en/media/news/storm-daniel-leads-extreme-rain-and-floods-mediterranean-heavy-loss-of-life-libya&quot; rel=&quot;noreferrer&quot;&gt;reports&lt;/a&gt; that during &amp;quot;Daniel&amp;quot;, precipitation of 414.1 mm was recorded in Al-Bayda within 24 hours (from 10 Sep 8am to 11 Sep 8am). If we assume, without knowledge of detailed precipitation patterns during the storm, that the entire drainage basin of Wadi Derna received 400mm of precipitation, this would amount to a total flood volume of 0.4m x 575 km&lt;sup&gt;2&lt;/sup&gt; = 0.23 km&lt;sup&gt;3&lt;/sup&gt;. Based on the landscape, almost all of the precipitation would have turned into surface run-off right away. Furthermore, the steep gradient of Wadi Derna would have caused the run-off to be conducted downstream at a rapid pace.&lt;/p&gt;&#xA;&lt;p&gt;For the massive flooding in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Ahr&quot; rel=&quot;noreferrer&quot;&gt;Ahr&lt;/a&gt; valley of Germany in 2021, with a somewhat lower gradient (&lt;a href=&quot;https://de.wikipedia.org/wiki/Ahr&quot; rel=&quot;noreferrer&quot;&gt;421m difference&lt;/a&gt; in elevation over 85km), an expert &lt;a href=&quot;https://www.zeit.de/news/2022-10/07/fachmann-sieht-hohe-fliessgeschwindigkeit-auf-flutnacht-foto&quot; rel=&quot;noreferrer&quot;&gt;estimated&lt;/a&gt; a flow speed of &amp;quot;several meters per second&amp;quot; (to my knowledge no actual measurements exist because necessary equipment was destroyed by the flood). If we take &amp;quot;several meters&amp;quot; to mean at least 3 meters, this would equate to about 11km per hour. This means that an unimpeded flood wave would have reached Derna within seven hours.&lt;/p&gt;&#xA;&lt;p&gt;Because of significant flood events affecting Wadi Derna every few decades, two flood-control dams were constructed in the 1970s: One at the southern city limit of Derna (32.753, 22.631) and a second one some 17km upstream (32.659, 22.577). These dams were of earthen construction: essentially layers of compacted clay. They each had a concrete bell-mouth &lt;a href=&quot;https://en.wikipedia.org/wiki/Spillway&quot; rel=&quot;noreferrer&quot;&gt;spillway&lt;/a&gt;, roughly in the shape of a vertically oriented trumpet. Both dams and their spillway structures are clearly visible on the satellite view of Google maps. Would the volume of water that could be impounded behind these dams have been sufficient to temporarily buffer a flood volume of 0.23 km&lt;sup&gt;3&lt;/sup&gt;?&lt;/p&gt;&#xA;&lt;p&gt;Reliable data on these two dams is hard to come by. According to one &lt;a href=&quot;https://eos.org/thelandslideblog/the-failed-dams-in-wadi-derna-in-libya&quot; rel=&quot;noreferrer&quot;&gt;source&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The dams were constructed in the 1970s by a Yugoslavian company. The upper dam was called the Al-Bilad Dam, with a storage capacity of 1.5 million cubic metres of water, whilst the lower dam, the Abu Mansour Dam, had a storage capacity of 22.5 million cubic metres. The dams had a core of compacted clay with a carapace of stone.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I am quite skeptical about the lower number here, as the two dams visually look similar in size, and even accounting for different valley cross sections should not lead to such a huge difference in impounded volume. A conservative upper estimate might be that both dams combined could hold 2 x 22.5 million = 45 million cubic meters, or 0.045 km&lt;sup&gt;3&lt;/sup&gt;, so about one fifth of the flood volume computed above. The spillways would have been unable to cope with the volume of water, leading to an overtopping of the two dams in sequence. Footage from other dam disasters, such as the collapse of the Teton Dam in 1976 indicates that a dam of earthen construction that is affected by water erosion on its downstream face will disintegrate &lt;em&gt;rapidly&lt;/em&gt;, leading to an equally rapid release of the water impounded behind it.&lt;/p&gt;&#xA;&lt;p&gt;Amateur &lt;a href=&quot;https://www.youtube.com/watch?v=YQfRHJpafK8&quot; rel=&quot;noreferrer&quot;&gt;video footage&lt;/a&gt; of one of the dams in its current state, posted on YouTube by &lt;em&gt;The Independent&lt;/em&gt;, shows that the dam is completely gone except for the concrete spillway structure, consistent with total destruction as a result of overtopping. According to &lt;a href=&quot;https://apnews.com/article/libya-floods-derna-storm-daniel-dams-collapse-40e48e454b6d903f1a194d95d4758d19&quot; rel=&quot;noreferrer&quot;&gt;news reports&lt;/a&gt;, both of the flood-control dams were destroyed, and as a consequence a massive wall of water inundated the city of Derna, located directly below the lower dam, &lt;a href=&quot;https://www.nbcnews.com/video/eyewitness-tells-of-60-foot-wall-of-water-flooding-derna-libya-192935493896&quot; rel=&quot;noreferrer&quot;&gt;claimed by eyewitnesses&lt;/a&gt; to be up to 60 feet (~ 18m) in height.&lt;/p&gt;&#xA;" OwnerUserId="5255" LastEditorUserId="5255" LastEditDate="2023-09-16T09:38:22.647" LastActivityDate="2023-09-16T09:38:22.647" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25567" PostTypeId="1" AcceptedAnswerId="25568" CreationDate="2023-09-15T20:28:23.633" Score="2" ViewCount="189" Body="&lt;p&gt;In discussions with physically educated among the deniers of the greenhouse effect, it is repeatedly claimed that it is completely pointless to state a quantity such as a global average temperature of the earth, since the temperatures of the earth's surface are very variable in time and space.&#xA;This objection does not seem to me to be completely absurd. Which physical content has actually this global average temperature?&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;Does its value say anything at all about the total energy stored in the atmosphere?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Can this value be used to check the radiation balance according to the Stefan-Boltzmann law? Especialy since the averages &lt;span class=&quot;math-container&quot;&gt;$\overline{T^4}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;${\overline T}^4$&lt;/span&gt; may be different.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I do not want to discuss here whether the measuring procedures for the production of such a value may be sufficient. My question refers only to the conceptual.&lt;/p&gt;&#xA;&lt;p&gt;I am also already grateful for references to articles, and I apologize in advance to the moderation if there is already a discussion on this that I have overlooked.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;REPLY I&lt;/p&gt;&#xA;&lt;p&gt;Thanks to all also for the references. Yes I was inaccurate myself, it is of course the global surface temperature that I mean.&lt;/p&gt;&#xA;&lt;p&gt;My question implies, whether it is possible, in principle at least, to calculate the current warming &lt;span class=&quot;math-container&quot;&gt;$\overline T(c)$&lt;/span&gt; ab initio starting from the temperature &lt;span class=&quot;math-container&quot;&gt;$\overline T(0)$&lt;/span&gt; of an atmosphere without any greenhouse gas &lt;span class=&quot;math-container&quot;&gt;$c_{\mathrm{CO}_2,...}=0$&lt;/span&gt; to additional input of carbon dioxide etc.&lt;/p&gt;&#xA;&lt;p&gt;The common textbook examples always assume very rough simplifications when determining this &lt;span class=&quot;math-container&quot;&gt;$\overline T(0)$&lt;/span&gt; in it: no spherical geometry, no rotation or very fast rotation etc.&#xA;(Maybe I should formulate another separate question thread to this pure calculation problem?)&lt;/p&gt;&#xA;&lt;p&gt;Regarding the public discussion: would you agree with my formulation that the common climate models consider temperature changes in contrast to absolute values? The relevant value for calculating would then not be this &lt;span class=&quot;math-container&quot;&gt;$\overline T(0)$&lt;/span&gt; but rather the climate sensitivity, which can be determined in other ways?&lt;/p&gt;&#xA;&lt;p&gt;REPLY II&lt;/p&gt;&#xA;&lt;p&gt;The mean temperature of the earth is therefore only an indicator. Simplified said, if the average temperature increases, then in any case also the total energy content of the atmosphere increases. In this respect this value is reasonable.&lt;/p&gt;&#xA;&lt;p&gt;My doubts refer to a calculation often reproduced in textbooks. One compares the temperature, which the earth would have without greenhouse gases (on the basis of a calculation with the law of Stefan-Boltzmann) with the &amp;quot;measured&amp;quot; global average temperature of the earth. One obtains a value around -20°C without greenhouse gases and attributes the difference to the &amp;quot;measured&amp;quot; approximate global temperature of +15°C to the greenhouse effect and from this also obtains an estimate of the climate sensitivity of climate gases.&#xA;However, this simple calculation alone seems physically disputable in several respects.&lt;/p&gt;&#xA;&lt;p&gt;So thanks for the clarifying addition.&lt;/p&gt;&#xA;" OwnerUserId="29644" OwnerDisplayName="Cisfinite" LastEditorUserId="29644" LastEditDate="2023-09-22T09:31:35.670" LastActivityDate="2023-09-22T09:31:35.670" Title="Is the global temperature of the earth a physical quantity at all?" Tags="|thermodynamics|temperature|geophysics|" AnswerCount="2" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="25568" PostTypeId="2" ParentId="25567" CreationDate="2023-09-15T22:53:39.160" Score="15" Body="&lt;p&gt;There is no unique way to define a global average temperature of the Earth, but that does not mean that calculation of such a quantity is &amp;quot;pointless&amp;quot;. If someone tells me that the average surface temperature of Venus is 475°C, I don't need to know the details of how it is determined or if it varies with time or place to know that I don't want to live there. Similarly, scientific understanding of how the Earth's surface is warming does not depend on a particular definition of the Earth's average surface temperature, but being able to state such a number and how it is changing can be very useful in communicating with policy makers and the public.&lt;/p&gt;&#xA;&lt;p&gt;A single global average temperature cannot be used to check the radiation balance according to the Stefan-Boltzmann law. Instead, the radiation balance can actually be used for a definition of an average temperature better known as the &lt;a href=&quot;https://en.wikipedia.org/wiki/Stefan%E2%80%93Boltzmann_law#Effective_temperature_of_the_Earth&quot; rel=&quot;noreferrer&quot;&gt;Earth's effective temperature&lt;/a&gt; of 255 K. Similarly, another well-known global average temperature is actually the the &lt;a href=&quot;https://en.wikipedia.org/wiki/UAH_satellite_temperature_dataset&quot; rel=&quot;noreferrer&quot;&gt;temperature of the lower troposphere&lt;/a&gt; based on satellite measurements of atmospheric oxygen radiance in the microwave band.&lt;/p&gt;&#xA;&lt;p&gt;Depending on one's definition, the &amp;quot;global average temperature of the Earth&amp;quot; could range from to 255K to 3000 K, where the &lt;a href=&quot;https://physics.stackexchange.com/a/758696/145491&quot;&gt;latter&lt;/a&gt; is the temperature averaged over the entire volume of the Earth.&lt;/p&gt;&#xA;&lt;p&gt;What I believe you are asking about is actually the Earth's global average &lt;strong&gt;surface&lt;/strong&gt; temperature.  When people quote this temperature, it is from a model (e.g. &lt;a href=&quot;https://data.giss.nasa.gov/gistemp/&quot; rel=&quot;noreferrer&quot;&gt;GISTEMP v4&lt;/a&gt;) based on many measurements from all over the Earth. &amp;quot;Surface&amp;quot; temperatures are usually nominally the temperature of the air about 2 metres above the Earth's surface.  Although different models may not agree precisely, &lt;a href=&quot;https://en.wikipedia.org/wiki/Instrumental_temperature_record#/media/File:20200324_Global_average_temperature_-_NASA-GISS_HadCrut_NOAA_Japan_BerkeleyE.svg&quot; rel=&quot;noreferrer&quot;&gt;their results are strongly correlated&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;None of these single global temperature values can be used to simply determine the total energy stored in the atmosphere since the temperature and pressure vary with location and height, but as @mmesser314 notes in their comment, it is the ocean, not the atmosphere, that &lt;a href=&quot;https://www.climate.gov/news-features/understanding-climate/climate-change-ocean-heat-content&quot; rel=&quot;noreferrer&quot;&gt;stores most (~90%)&lt;/a&gt; of the excess heat in the Earth's climate system.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;strong&gt;Addition in response to &amp;quot;REPLY&amp;quot; edit&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Yes, the important point for currently calculating a &lt;a href=&quot;https://en.wikipedia.org/wiki/Global_surface_temperature&quot; rel=&quot;noreferrer&quot;&gt;global average temperature&lt;/a&gt; is not to know its absolute value, but that the changes in that value show in a simple way that the Earth is slowly warming. These changes are not monotonic, but the trend is clear and our best scientific models predict that this warming will continue dangerously unless global humanity modifies its activities. If the &lt;a href=&quot;https://en.wikipedia.org/wiki/Boiling_frog&quot; rel=&quot;noreferrer&quot;&gt;fabled frog&lt;/a&gt; had monitored the average temperature of the water in its pot and extrapolated the trend, it might have jumped and survived.&lt;/p&gt;&#xA;&lt;p&gt;Simple models are very often useful in physics, but one must be cautious to avoid over-simplified &lt;a href=&quot;https://en.wikipedia.org/wiki/Spherical_cow&quot; rel=&quot;noreferrer&quot;&gt;&amp;quot;spherical cows&amp;quot;&lt;/a&gt; when trying to understand complex real-world phenomena. One could calculate a surface temperature for a simple model of an ideal uniform albedo featureless planet with an ideal cloudless &lt;a href=&quot;https://en.wikipedia.org/wiki/Greenhouse_effect&quot; rel=&quot;noreferrer&quot;&gt;greenhouse atmosphere&lt;/a&gt; illuminated by an ideal constant star, but such a model would be of very limited use in accurately understanding the Earth's climate system. If a galactic super-civilization actually created such a system as an solar-system sized experiment, all the initial simplifications would soon fail:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The surface would heat and then warm the atmosphere, starting convection which causes winds that distribute heat over the planet's surface.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;If the model atmosphere was based on the Earth's, then water vapour would be one of the major greenhouse gases and this would quickly wreck the &amp;quot;uniform featureless&amp;quot; assumption since it may precipitate out forming heat-absorbing oceans or heat-reflecting ice, or clouds that (depending on their details) may also trap or reflect heat and which dynamically form, move, and disappear.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Once there is moving water, it will start to erode the formerly featureless surface creating topography that affect the movements of oceans and atmosphere.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Depending on how the planet's interior is constructed, &lt;a href=&quot;https://earthscience.stackexchange.com/q/762/27775&quot;&gt;water might trigger plate tectonics&lt;/a&gt;, causing more topographic changes and volcanic activity modifying the atmosphere's composition and increasing its variability.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;…&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;You get the idea. Modelling planets and their climate system is complex and tough.&lt;/p&gt;&#xA;" OwnerUserId="27775" OwnerDisplayName="David Bailey" LastActivityDate="2023-09-16T16:02:44.500" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25569" PostTypeId="1" CreationDate="2023-09-18T08:47:04.637" Score="0" ViewCount="221" Body="&lt;p&gt;I downloaded the latent heat flux from fluxnet, the latent heat flux is per hour in W m-2. I summed each value per hour of the day to get the daily sum.&lt;/p&gt;&#xA;&lt;p&gt;Now I have the daily sum of latent heat flux in W m-2 and want to daily evapotranspiration in mm.&lt;/p&gt;&#xA;&lt;p&gt;You can calculate this with the formula ET= λ LE/λ. First you calculate the heat of vaporization; λ = 2.501 – (2.361 x 10^-3) x Ta. Where Ta is temperature air in celcius, I also have this daily data.&lt;/p&gt;&#xA;&lt;p&gt;My calculations in my code (df stands just for dataframe and double ** is ^):&lt;/p&gt;&#xA;&lt;p&gt;df['heat_of_vaporization'] = 2.501-(2.361*10**-3)*df['TA_daily_average']&lt;/p&gt;&#xA;&lt;p&gt;df['ET'] = df['LE_daily_sum']/(df['heat_of_vaporization']*1000 *1000)*3600&lt;/p&gt;&#xA;&lt;p&gt;Is the calculation right? It think I get the good data. I did * 3600 because of the seconds in an hour, added all the hours so not 3600*24 I think. Are the *1000 *1000 also right?&lt;/p&gt;&#xA;" OwnerUserId="29624" LastEditorUserId="29624" LastEditDate="2023-09-19T22:25:53.150" LastActivityDate="2024-02-13T20:31:20.740" Title="Conversion calculation latent heat flux in hours in W m-2 to evapotranspiration per day in mm" Tags="|evapotranspiration|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25571" PostTypeId="1" CreationDate="2023-09-18T22:49:54.267" Score="0" ViewCount="60" Body="&lt;p&gt;I recently came across some intriguing specimens near a lake shore in Texas and am seeking your expertise to help identify them. The objects have a few characteristics that lead me to believe they could be fossils, but I would appreciate a more knowledgeable perspective.&lt;/p&gt;&#xA;&lt;p&gt;Description:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Size&lt;/strong&gt;: Each specimen is approximately 1-2 cm tall and has a thickness of about 1-2 mm.&#xA;&lt;strong&gt;Shape&lt;/strong&gt;: They have a leaf-like appearance.&#xA;&lt;strong&gt;Color&lt;/strong&gt;: One side of the specimens is dark brown, while the other side exhibits a pearl-white hue.&#xA;&lt;strong&gt;Location&lt;/strong&gt;: Found near a lake shore in Texas.&#xA;&lt;strong&gt;Surrounding Geology&lt;/strong&gt;: The geological context is not yet determined.&#xA;I have taken multiple photographs from various angles, and have also captured images with a scale for size reference.&lt;/p&gt;&#xA;&lt;p&gt;Does anyone have an idea what these could be? Are these likely to be fossils, and if so, what era or source could they be originating from?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/XPscD.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XPscD.jpg&quot; alt=&quot;Front side of &amp;quot;leaves&amp;quot;&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/JZwdh.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JZwdh.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22276" LastActivityDate="2023-09-18T22:49:54.267" Title="Are These Leaf Fossils Found Near a Texas Lake Shore?" Tags="|geology|rocks|fossils|paleobotany|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25572" PostTypeId="1" CreationDate="2023-09-19T15:02:07.373" Score="1" ViewCount="117" Body="&lt;p&gt;The University of Maine website &lt;a href=&quot;https://climatereanalyzer.org&quot; rel=&quot;nofollow noreferrer&quot;&gt;climatereanalyzer.org&lt;/a&gt; has a plethora of data visualizations, among them a display of 2 meter temperature anomalies.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://climatereanalyzer.org/wx/todays-weather/?var_id=t2anom&amp;amp;ortho=7&amp;amp;wt=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;image of Antarctica today&lt;/a&gt; is below, with a green circle added by me:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Fr5hn.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Fr5hn.jpg&quot; alt=&quot;2m temperature anomalies over Antarctica, Sep 19, 2023&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The circle shows a warm spot approximately covering the Ross Ice Shelf. The bright maximum temperature deviation in the center amounts to roughly 28K. A &lt;a href=&quot;https://climatereanalyzer.org/wx/todays-weather/?var_id=t2&amp;amp;ortho=7&amp;amp;wt=1&quot; rel=&quot;nofollow noreferrer&quot;&gt;temperature map&lt;/a&gt; shows that there is a spot on the shelf that's as warm as 0°C, still in the Antarctic winter.&lt;/p&gt;&#xA;&lt;p&gt;Other incursions of warm air are visible as well.&lt;/p&gt;&#xA;&lt;p&gt;On other days the air may not be quite as warm, but I commonly see &amp;quot;incursions&amp;quot; of air much warmer than average. I'm aware that the extremely dry and cold air over Antarctica is prone to larger temperature oscillations than usually observed in other places. Still, 28K seem quite extreme.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, nobody seems overly worried by the current state of affairs.&lt;/p&gt;&#xA;&lt;p&gt;This is in contrast to some extreme events that &lt;em&gt;made&lt;/em&gt; the headlines outside the professional community in the past years. One example is the off-the-charts temperature record in &lt;a href=&quot;https://berkeleyearth.org/antarctic-heatwave-rapid-attribution-review-dome-c-record/&quot; rel=&quot;nofollow noreferrer&quot;&gt;March 2022&lt;/a&gt;. I was wondering whether there is an underlying increase in events which raise eyebrows in the professional world but don't reach the general public, and whether an observation like this one is an example.&lt;/p&gt;&#xA;&lt;p&gt;Therefore I'm wondering how common such a situation is. As an idea of what I'm asking:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Have such events been observed 50 years ago? (Did we even look?)&lt;/li&gt;&#xA;&lt;li&gt;If yes, have they become more frequent?&lt;/li&gt;&#xA;&lt;li&gt;If yes, are you worried? ;-)&lt;/li&gt;&#xA;&lt;li&gt;Is it within the prediction range of the models? Upper range, lower range of the predictions?&lt;/li&gt;&#xA;&lt;li&gt;If not, are you worried?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="5396" LastEditorUserId="5396" LastEditDate="2023-09-22T13:20:11.270" LastActivityDate="2023-09-22T13:20:11.270" Title="Assessment of Antarctic temperature anomalies" Tags="|climate|temperature|antarctica|extreme-weather|" AnswerCount="0" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25573" PostTypeId="2" ParentId="9192" CreationDate="2023-09-20T10:36:48.813" Score="1" Body="&lt;p&gt;The Tohoku earthquake registered on both the superconducting gravimeter (SG) and broadband seismic networks.  The SGs are accelerometers with roughly 0.1 nanometer/second^2 sensitivity at 1 sample per second. The broadband seismometers are about 10 times less sensitive, but usually store at 40 sps or 100 sps.  And the broadband seismometers are three axis, so you get the benefit of three independent signals. The most practical way to begin using and calibrating a gravimeter array is to use time of flight methods (the speed of gravity and speed of electromagnetism are identical, not close, identical) globally. Very sensitive detectors at picometer/second^2 are practical and relatively low cost now.  Operating those at 1 MegaSamplePerSecond (Msps) gives roughly 300 meter resolution. And you would be modeling and tracking the seismic waves at the surface and interior, and also motions at the source.  So you can image the source region and use the gravity data to constrain the seismic (acoustic) models of the energy, direction and timing of the event. The global seismic arrays are fairly stable and sophisticated. There are &amp;quot;Big N&amp;quot; experiments with thousands of three axis seismic sensor that run up to 5000 sps. I have tried to test many of the new ones to see if they are potential gravimeter array detectors.&lt;/p&gt;&#xA;&lt;p&gt;The broadband seismometer usually report velocity (meters/second), but take the first time derivative and it is an &amp;quot;accelerometer&amp;quot;.  My rule for groups is &amp;quot;if you can track the sun and moon with your &amp;quot;accelerometer&amp;quot; then you can call it a &amp;quot;gravimeter&amp;quot;.  There are MEMS &amp;quot;gravimeters&amp;quot; now by that definition, where groups take methods used to make cell phone MEMS three axis accelerometers, and beef up the read out.  Those MEMS gravimeters drift, but you use the sun moon tidal signal (a huge signal that is most of what the SG records look like) and calibrate them continuously.  It is the most elegant thing I have ever worked on to see that two numbers (an offset and scale factor) are enough to fit the complex signal at a SG or gravimeter station for a month of data.  The reason it works so simple is that gravitational acceleration is almost pure Newtonian GM/r^2 -if you use the precise positions of the sun moon earth and use vector calculations to the station. The &amp;quot;trick&amp;quot; is that you have to subtract the acceleration of the sun and moon on the center of the earth, add the rotational acceleration for latitude, and use JPL or Python to get the positions of the Earth Sun Moon every second.&lt;/p&gt;&#xA;&lt;p&gt;You could possibly use three LIGO &amp;quot;detectors&amp;quot; to try tracking earthquakes. But their strain data is only 16384 sps (about 18 km) and they are huge and really tedious to use their data. And they did not remove the &amp;quot;Newtonian noise&amp;quot; from their methods well. They do not share their earth and solar system data at all. And there are atom interferometer, atomic clock gravitational sensors, Bose Einstein gravimeters, electrochemical gravimeters, electron interferometers gravimeters, and many sensitive small ways to measure atomic scale displacements over time.  You can use an atomic force sensor and record the data at up to Msps or even Gsps now.  There are so many ways to measure gravity for this sort of thing now, I almost gave up trying to track them all.&lt;/p&gt;&#xA;&lt;p&gt;I paid attention to that earthquake because my son and his wife were living in north Tokyo and had just moved there from Sendai, near where the earthquake hit.  I studied gravitational detection at UMD College Park.  Joe Weber wanted his detector to be used for communication.  Robert Forward his student and collaborator wanted gravitational methods to be practical.  I call it &amp;quot;gravitational engineering&amp;quot; because of them.&lt;/p&gt;&#xA;&lt;p&gt;There are lots of ways to measure the speed of gravity now.  So that is my second hurdle. &amp;quot;If your array can measure speed of gravity precisely&amp;quot; then it it can be called &amp;quot;a gravitational imaging detector array&amp;quot;.  That is the first thing you want to do when you calibrate your array - check to make sure it measure the speed of gravity and use some earthquakes to calibrate.  You can also use cars on the highway if you track and classify them with precise locations and times. Surf waves with 3D models can also work.  I got into this because I used the SGs to measure the speed of gravity.  it was ambiguous because of &amp;quot;single axis&amp;quot; so that is why I spent close to a year to go through ALL the IRIS.edu seismometers and check decades of records to find quiet sites where the sun moon tidal signal is clear on all three axes. Those only require 6 numbers, linear regression for each axis.  Really very beautiful how well Newton and basic vector calculations work for everyday things.  When you do time of flight gravity sensing, it gets complex again, because all the frequency of &amp;quot;gravity signals&amp;quot; are accessible now - up to about 100 GHz. But people talk about x-ray and gamma ray frequencies for gravitational signals.  Most of the &amp;quot;quantum detectors&amp;quot; and many &amp;quot;entanglement&amp;quot; detectors and communications systems are likely very good high frequency gravitational sensors.  It starts with tracking the sun and moon vector tidal signal, and then &amp;quot;measure the speed of gravity&amp;quot;. After that it is just &amp;quot;gravitational engineering&amp;quot; with first year vector calculus and off the shelf low noise amplifiers and high bit high sampling rate ADCs.&lt;/p&gt;&#xA;&lt;p&gt;Richard Collins, The Internet Foundation&lt;/p&gt;&#xA;" OwnerUserId="29668" LastActivityDate="2023-09-20T10:36:48.813" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25575" PostTypeId="1" CreationDate="2023-09-21T05:38:57.723" Score="1" ViewCount="58" Body="&lt;p&gt;I've found it surprisingly hard to find an answer to this question.&lt;/p&gt;&#xA;&lt;p&gt;Niue is an uplifted coral reef jutting above the ocean. The rock is all limestone, and there is evidence for it being around for considerable time. There are many places where you can find caves that are exposed to air, and the formations inside those caves, while smoothed with time and exposure to the elements, are nonetheless impressive (Talava Arches and Avaiki cave are a couple of examples). The size of these formations suggests they were underground (but above water) for at least several hundred thousand years before becoming exposed to the outside world.&lt;/p&gt;&#xA;&lt;p&gt;That's as far as I've got. Various histories of the Island I've read always seem to start with colonisation in 900 AD.&lt;/p&gt;&#xA;" OwnerUserId="29675" LastActivityDate="2023-09-21T05:38:57.723" Title="How old is Niue?" Tags="|limestone|age|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25576" PostTypeId="1" AcceptedAnswerId="25577" CreationDate="2023-09-21T07:42:06.083" Score="3" ViewCount="439" Body="&lt;p&gt;Layman here, sorry if this is a stupid question. I have a geology friend who recently told me that plate tectonics is like how warm milk cools on top to form thin solid layers. The convection cells in the warm milk drive these solid layers around like a conveyor belt. You can have layers emerge through ridges at places of upwelling of mantle convection, and layers subduct at places of downwelling.&lt;/p&gt;&#xA;&lt;img src=&quot;https://i.stack.imgur.com/rNiaZ.png&quot; width=&quot;300&quot;&gt;&#xA;&lt;p&gt;But the idea of 'circulation' implies 'recycling', right?. Does continental crust that gets subduced inside the mantle, come back up on the other side as new crust at the ridges?&lt;/p&gt;&#xA;" OwnerUserId="27998" LastActivityDate="2023-09-21T19:50:07.357" Title="Do subducted continents rise up again through ridges?" Tags="|geology|plate-tectonics|crust|mantle|continental-crust|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25577" PostTypeId="2" ParentId="25576" CreationDate="2023-09-21T10:30:59.757" Score="5" Body="&lt;p&gt;Milk is a bad analogy because the earth's bulk, mantle and lithosphere, is solid. But the mantle - because of pressure and temperature - is not rigid, rather ductile. As such, it slowly (cm/year) convects as a solid body, and this convection is thought to play a (minor) role in driving plate tectonics.&lt;/p&gt;&#xA;&lt;p&gt;Mantle material rising under (and thus partly melting because of pressure release) and erupting at mid ocean ridges form new, hot oceanic crust. That cools and gets denser as it spreads until it finally is so dense that it sinks back into the mantle, forming a new subduction zone. A soft, partly (a few %) molten layer called Asthenosphere allows for this. In contrast to the ocean ridge the partial melt in a subduction happens because of fluid injection.&lt;/p&gt;&#xA;&lt;p&gt;Now what about continents? While the ocean floors around are constantly constructed in mid ocean ridges and destructed in subduction zones, limiting ocean floor age to about 200 million years (and supporting the notion of recycling processes and cycles at work), continents are of a less dense material that floats around without subducting. The oldest rocks on earth (current record holder &lt;a href=&quot;https://www.nature.com/articles/ngeo2075&quot; rel=&quot;nofollow noreferrer&quot;&gt;4.3 billion&lt;/a&gt; years are on continental crust and they have already been through something.&lt;/p&gt;&#xA;&lt;p&gt;We said &lt;strong&gt;continents don't subduct&lt;/strong&gt;, at least not like oceanic lithosphere, but when &lt;strong&gt;continents collide&lt;/strong&gt; after the ocean parting them has completely subducted, they get stacked and folded, some parts pushed up others down, which thickens crust and lithosphere and forms imposing mountains and elevated plateaus, like the Himalayas today. See &lt;a href=&quot;https://www.nps.gov/subjects/geology/plate-tectonics-collisional-mountain-ranges.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;this link&lt;/a&gt; for a visual approach to what happens when continents collide.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Can they come out again? No, not just like that&lt;/strong&gt;. Continental material that gets into some depth because of the stacking comes under &lt;a href=&quot;https://australian.museum/learn/minerals/shaping-earth/types-of-metamorphism/&quot; rel=&quot;nofollow noreferrer&quot;&gt;metamorphism&lt;/a&gt; which exists in different forms, but essentially means the rocks are transformed under pressure and heat. The mountains on top weather away and flow out at the sides under the forces of erosion and gravity, and even the lower storeys, the metamorphic rocks, can come to the surface again (remember, they are less dense than the underlying mantle material, they have a tendency to rise) and be exposed to weathering and erosion.&lt;/p&gt;&#xA;&lt;p&gt;So, tl,dr:&#xA;&lt;strong&gt;Continents do not subduct. They can collide and form huge mountain ranges. These weather and erode over time.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user29219" LastEditorDisplayName="user29219" LastEditDate="2023-09-21T19:50:07.357" LastActivityDate="2023-09-21T19:50:07.357" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25578" PostTypeId="1" CreationDate="2023-09-21T11:39:35.510" Score="4" ViewCount="173" Body="&lt;p&gt;The permanent snow line in the Alps is around 10,000 ft (3,000 m) elevation. This was further confirmed by a passenger flight I took late June where the screen showed 0°C (freeze point) around 10,000 ft north of NYC (and therefore, in summer above a temperate region).&lt;/p&gt;&#xA;&lt;p&gt;However, temperature is said to fall 6.5°C each 1000 m. In Central and Western Europe, temperatures reach up to 40°C each summer. If we assume 35°C for a mid-summer day at sea level, the temperature should be 9°C at 4000 m (13,100 ft) and 2.5°C at 5000 m (16,400 ft). So according to that formula, the permanent snow line should be well above all Alps (the highest is Mont Blanc around 4810 m) as all snow should have molten on a warm summer day. If we assume 26°C at sea level, 0°C should be reached at 4000 m according to the above formula. Yet, many considerably lower Alps are covered by snow year-round, as low as ~3,000 m.&lt;/p&gt;&#xA;&lt;p&gt;Did I miss something? Is the snow high up in the Alps just too robust to melt away even if temperatures are considerably above freeze point? Or can't one apply the above formula for temperate regions / mid-latitudes of Earth (as obviously was indicated in the airplane too)?&lt;/p&gt;&#xA;" OwnerDisplayName="user29677" LastActivityDate="2023-09-22T12:11:46.263" Title="Shouldn't the permanent snow line be considerably higher in the Alps and on Mt Hood if temperature falls 6.5°C per 1000 meters?" Tags="|temperature|atmosphere-modelling|mountains|snow|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25579" PostTypeId="1" AcceptedAnswerId="25625" CreationDate="2023-09-21T15:15:13.980" Score="3" ViewCount="115" Body="&lt;p&gt;Why are particulate matter measurements (like PM2.5) from an air quality monitor given in micrograms per cubic meter (μg / mm^3)?  Specifically, why &lt;em&gt;mass&lt;/em&gt;?&lt;/p&gt;&#xA;&lt;p&gt;I assume the device is using an optical system to count particles in a sample volume the air, and extrapolating as necessary to a standard volume like a cubic meter.&lt;/p&gt;&#xA;&lt;p&gt;If the device does indeed count particles, how does it convert that to mass?  Is the mass of 2.5 micron particles suspended in air consistent enough that multiplying the count by the average mass yields a good estimate?  Is a correction factor for air pressure applied to account for the fact that heavier particles are more likely to settle out of suspension when the air pressure drops?  (My particular monitor does not report air pressure, but I suppose it might still monitor it.)&lt;/p&gt;&#xA;&lt;p&gt;Is the health concern of breathing small particulates in a particular size category based on the total &lt;em&gt;mass&lt;/em&gt; of them inhaled or the &lt;em&gt;quantity&lt;/em&gt; of them?&lt;/p&gt;&#xA;&lt;p&gt;Intuitively, I would have expected the measurements to be presented in parts per million or as a count of particles per volume, not only because of how (I assume) it's measured, but also because of the utility.&lt;/p&gt;&#xA;" OwnerUserId="5164" LastActivityDate="2023-10-06T02:23:45.453" Title="Why (and how) is particulate matter measured in mass per volume?" Tags="|measurements|air-quality|pm2.5|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25580" PostTypeId="2" ParentId="25578" CreationDate="2023-09-21T17:42:56.310" Score="2" Body="&lt;p&gt;There are a couple of issues that you need to add to your picture.&lt;/p&gt;&#xA;&lt;p&gt;First, the temperature varies over time so it is not constant at a certain elevation throughout e.g. the summer.&lt;/p&gt;&#xA;&lt;p&gt;Second, snow will melt from the energy provided to the snow pack. This energy is not exclusively expressed as temperature. The energy fluxes that reach the ground and can provide energy for melt include&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Long wave radiation (infra red)&lt;/li&gt;&#xA;&lt;li&gt;Short wave radiation (visible light)&lt;/li&gt;&#xA;&lt;li&gt;Sensible heat (heat content of the air convected towards the surface&#xA;due to turbulence)&lt;/li&gt;&#xA;&lt;li&gt;Latent heat (Air moisture advected to the surface through turbulence;&#xA;a phase change from gas to liguid during condensation expells heat)&lt;/li&gt;&#xA;&lt;li&gt;Energy contained in rain drops, i.e. the temperature of the rain water, falling on the surface&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The radiation will in part be reflected so not all incoming radiation will be available for melting. A new fresh snow surface can reflect as much as 90% of the incoming radiation, we say the snow has an albedo of 0.9 where 1 is 100% reflection and 0 is no reflection at all. Snow surface commonly have lower albedo since there may be dust and other particles that can accumulate and lower the albedo making the snow pack absorb more radiation thereby allowing more energy to contribute to melting. Wet snow also lowers the albedo, particularly for long wave radiation.&lt;/p&gt;&#xA;&lt;p&gt;A melting snow surface will always be at the melting point, essentially zero but particularly the radiation components will contribute energy to cause melting at subzero temperatures. It is common to experience wet snow with a thin frozen crust in spring when incoming radiation is high but air temperature may be below zero. The radiation causes subsurface melt while the cold air keeps the crust frozen.&lt;/p&gt;&#xA;&lt;p&gt;When snow covers rocky ground some radiation will heat rocks that protrude the cover and help snow to melt in the proximity of such rocks. If the snow cover is thin the ground may be heated from absorbing the radiation and cause melting at the base of the snow pack. Radiation can penetrate about a meter of snow (depends on density) so when the snow pack is a few dm or so a fair portion of radiation will reach the ground beneath the snow pack.&lt;/p&gt;&#xA;&lt;p&gt;Bare paches of ground will absorb more radiation that the snow cover surrounding the patches and become heat islands in the general snow cover. The air above these patches will warm up due to the warm ground and in the presence of wind provide warm air for melting in the near surroundings.&lt;/p&gt;&#xA;&lt;p&gt;So, in conclusion, there are several processes we need to consider when trying to understand the snow line, one is the heat balance and the other is the micro-climate that result from surfaces having different albedo. Therefore the snow line elevation will move up in elevation during the melt season due to the cumulative effect of what has been discussed above.&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="20607" LastEditDate="2023-09-22T12:11:46.263" LastActivityDate="2023-09-22T12:11:46.263" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25581" PostTypeId="2" ParentId="25561" CreationDate="2023-09-21T23:57:10.373" Score="2" Body="&lt;p&gt;As some comments suggest, nothing substitutes for a globe and a tape measure. But there is a subtle hint of the outcome.&lt;/p&gt;&#xA;&lt;p&gt;Australia is southeast of Sweden according to latitudes and longitudes, but that means little on a spherical Earth. The latitude of Mecca is south of Chicago's, but mosques in the latter city are built to facilitate the Muslim patrons facing &lt;em&gt;north&lt;/em&gt;-east, along the Great Circle route which (in the Northern Hemisphere) deviates north from the compass direction.&lt;/p&gt;&#xA;&lt;p&gt;In the case of Sweden, that country is so far north that the &amp;quot;northern deviation&amp;quot; of Great Circle routes to distant lands around the Pacific Ocean carries that route near the North Pole itself. Then we may well expect northern Sweden, being closer to the North Pole, to be closer to those far-off destinations.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2023-09-21T23:57:10.373" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25582" PostTypeId="2" ParentId="25567" CreationDate="2023-09-22T00:38:29.327" Score="2" Body="&lt;p&gt;A global average surface air temperature is not a physical quantity in and of itself but it does provide a reliable indicator of changes to physical properties of global climate. When scientists began looking for indications of global climate change the existing archives of weather records, including (usually) daily maximums and minimums, were found to be useful and they continue to be a principle data source.&lt;/p&gt;&#xA;&lt;p&gt;These have been augmented by a variety of direct and indirect measurements, including proxy data going back before temperature records. Some are measuring physical properties, eg measurements of ocean, land and atmosphere heat content, or snow cover or ice mass changes or sea levels, but most do not go back as far as weather station data.&lt;/p&gt;&#xA;&lt;p&gt;Ocean heat content is a real physical quantity -&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/He1RW.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/He1RW.png&quot; alt=&quot;Ocean Heat Content&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The difference between how much energy reaches Earth and how much is radiated back to space is real physical quantity -&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/oJIxq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oJIxq.png&quot; alt=&quot;Energy Imbalance&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2023-09-22T00:38:29.327" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25583" PostTypeId="1" AcceptedAnswerId="25584" CreationDate="2023-09-22T09:30:21.687" Score="1" ViewCount="287" Body="&lt;p&gt;Why are eastern Oregon, southeastern Washington and southern Idaho so arid, as compared to the humid and lush western Oregon and Washington? In Oregon and Washington there is quite an abrupt boundary around the 121st longitude. Is the Cascade Range really that high to block most rain clouds from going further east? I've got the impression that only exceptional mountains of the range (volcanoes such as Mt Hood and Mt Adams) would be high enough for that.&lt;/p&gt;&#xA;" OwnerDisplayName="user29677" LastEditorDisplayName="user29677" LastEditDate="2023-09-22T09:37:03.753" LastActivityDate="2023-09-22T11:58:42.297" Title="Why are eastern Oregon and southeastern Washington so dry?" Tags="|meteorology|rainfall|humidity|vegetation|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25584" PostTypeId="2" ParentId="25583" CreationDate="2023-09-22T11:42:53.427" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://laulima.hawaii.edu/access/content/group/dbd544e4-dcdd-4631-b8ad-3304985e1be2/book/chapter_6/lifting.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;Orographic precipitation&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;There are mountain ranges (Coast and Cascade Range) perpendicular to the main wind direction. Mountains don't &amp;quot;block&amp;quot;, they force the air on the windward side up, thus &lt;a href=&quot;https://en.wikipedia.org/wiki/Adiabatic_process#Adiabatic_heating_and_cooling&quot; rel=&quot;nofollow noreferrer&quot;&gt;cooling&lt;/a&gt; it, and the water it contains to condensate end eventually rain out. That makes the windward side much wetter than the leeward side, where the air then arrives much drier, and in cases also warmer.&lt;/p&gt;&#xA;&lt;p&gt;See also:&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Climate_of_Oregon&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Climate_of_Oregon&lt;/a&gt; and the same for Washington.&lt;/p&gt;&#xA;&lt;p&gt;There's more:&#xA;When conditions are just right an effect called &lt;a href=&quot;https://en.wikipedia.org/wiki/Foehn_wind&quot; rel=&quot;nofollow noreferrer&quot;&gt;foehn&lt;/a&gt; develops, with a characteristic &lt;a href=&quot;https://www.weatheronline.co.uk/reports/wxfacts/Foehn-wall-picture.htm&quot; rel=&quot;nofollow noreferrer&quot;&gt;wall&lt;/a&gt; over the main ridge and &lt;a href=&quot;https://cloudatlas.wmo.int/es/species-altocumulus-lenticularis-ac-len.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Altocumulus lenticularis&lt;/a&gt; on the leeward side, with hot, very dry and windy conditions there.&lt;/p&gt;&#xA;" OwnerDisplayName="user29219" LastEditorDisplayName="user29219" LastEditDate="2023-09-22T11:58:42.297" LastActivityDate="2023-09-22T11:58:42.297" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25585" PostTypeId="1" CreationDate="2023-09-22T18:12:36.130" Score="1" ViewCount="56" Body="&lt;p&gt;I want to extract relative humidity at a specific pressure level (850 hPa) using metpy. Earlier, I tried with wrf-python function 'wrf.interplevel' and it worked successfully. But, I was getting some NaN values over high mountains like over the Himalaya region. Therefore, it is difficult to compare between the ERA-5 reanalysis data and model output as values are present over the high mountains in case of ERA-5 data.Therefore, I tried another approach using metpy function metpy.interpolate.interpolate_to_isosurface for the inetrpolation of relative humidity data at 850 hPa level.&lt;/p&gt;&#xA;&lt;p&gt;But, I am getting the follwoing error:&#xA;IndexError: &lt;strong&gt;Unlabeled multi-dimensional array cannot be used for indexing: bottom_top&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;For your convenience, my python code is given in the following:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;from netCDF4 import Dataset&#xA;import xarray as xr&#xA;import numpy as np&#xA;from wrf import (getvar, interplevel, interpz3d, vertcross, &#xA;                 CoordPair, ALL_TIMES, to_np,&#xA;                 get_cartopy, latlon_coords,&#xA;                 cartopy_xlim, cartopy_ylim)&#xA;import metpy.calc as mpcalc&#xA;from metpy.interpolate import interpolate_to_isosurface&#xA;from metpy.units import units    &#xA;input_path = &amp;quot;wrfout_d02_2017-10-26_00_00_00&amp;quot;&#xA;output_path = &amp;quot;/data/RelativeHumidity850hPa_d02.nc&amp;quot;&#xA;ncfile = Dataset(input_path, 'r')&#xA;ds = xr.open_dataset(input_path)&#xA;lat = np.nanmean(ds.XLAT, axis=(0, 2))&#xA;lon = np.nanmean(ds.XLONG, axis=(0, 1))&#xA;time_var = ncfile.variables['XTIME']&#xA;new_t = time_var[72:]&#xA;p = getvar(ncfile, &amp;quot;pressure&amp;quot;)&#xA;l = np.nanmean(p,axis=(1,2))&#xA;p_da = xr.DataArray(p, dims=('bottom_top', 'south_north',     'west_east'),coords=[('level', l), ('lat', lat), ('lon', lon)])&#xA;p_da=p_da * units.hPa&#xA;rh = getvar(ncfile, &amp;quot;rh&amp;quot;, timeidx=0)&#xA;rh = rh * units.percent&#xA;rh_da = xr.DataArray(rh, dims=('bottom_top', 'south_north', 'west_east'),coords=[('level', l), ('lat', lat), ('lon', lon)])&#xA;target_level = 850.0&#xA;target_level_hpa = target_level * units.hPa&#xA;rh_850 = interpolate_to_isosurface(p_da, rh_da, target_level_hpa)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Can anyone please help me to solve the error? That will be very helpful for me. Thank you for your time.&#xA;With regards,&#xA;Ankan&lt;/p&gt;&#xA;" OwnerUserId="29686" LastEditorUserId="6298" LastEditDate="2023-09-22T20:07:55.667" LastActivityDate="2023-09-22T20:07:55.667" Title="Error message in metpy function interpolate_to_isosurface for relative humidity variable from wrf" Tags="|python|wrf|wrf-chem|interpolation|metpy|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25586" PostTypeId="1" CreationDate="2023-09-22T19:34:38.737" Score="1" ViewCount="36" Body="&lt;p&gt;I am looking to get an averaging kernel (methane related calculations) for Sentinel 2 like the one for TROPOMI? Where do I find it? Trying to use this for simulating observed column concentrations from methane concentrations generated from dispersion models.&lt;/p&gt;&#xA;" OwnerUserId="29688" LastActivityDate="2024-03-11T07:31:37.517" Title="Sentinel 2p Averaging Kernel" Tags="|methane|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25588" PostTypeId="1" CreationDate="2023-09-23T13:56:53.560" Score="3" ViewCount="106" Body="&lt;p&gt;This is from paper &amp;quot;&lt;a href=&quot;https://ceramics.onlinelibrary.wiley.com/doi/abs/10.1111/j.1151-2916.1930.tb16222.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;The packing of particles&lt;/a&gt;&amp;quot; by A.E.R Westman and H.R. Hugill.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Here they give result as, &amp;quot;it is evident that if the diameter ratio is&#xA;unity, ie., the coarse and fine particles have the same diameter,&#xA;there will be no shrinkage on mixing and the Va curve will be the&#xA;straight line,  CF. On the other hand, if the coarse  particles have&#xA;a diameter which is infinitely  greater than that of the fine particles,&#xA;a different Vu curve will be obtained. On adding fine particles to a&#xA;quantity of coarse  particles, the fine will pack in the voids in the&#xA;coarse and the apparent volume of the mix will be equal to that of the&#xA;coarse particles. The Va curve corresponding to FIG. 4. -Packing in&#xA;two-size systems: Diameter ratio = 8.0. this state of affairs is a&#xA;straight line joining the point C in Fig. 2 with the right hand lower&#xA;corner of the diagram.  On adding coarse particles to a large quantity&#xA;of fines, the solid coarse particles will be immersed in the fines and&#xA;the Vu curve will be the straight line joining F, Fig. 2, to the point&#xA;1.00 at the left side of the diagram. These straight lines cross at R and thus CRF gives the Vu  curve for the case when the coarse&#xA;particles are infinitely larger than  the fine particles.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rzKIz.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rzKIz.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Can anyone explain what they mean and what they were trying to prove?&lt;/p&gt;&#xA;" OwnerUserId="29691" LastEditorUserId="6298" LastEditDate="2023-09-23T20:44:54.080" LastActivityDate="2023-10-03T18:28:47.113" Title="How is the apparent volume affected by particle packing?" Tags="|geology|geophysics|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25589" PostTypeId="1" CreationDate="2023-09-23T18:23:20.847" Score="1" ViewCount="128" Body="&lt;p&gt;Cumulonimbus clouds are associated with thunderstorms. Firecrackers which go up high in the sky and then burst into glittering show, can such crackers be injected in a cumulonimbus cloud and then burst to create a cloud seeding effect thus subsiding all the momentum building up in those clouds which can cause thunderstorms?&lt;/p&gt;&#xA;" OwnerUserId="22476" LastActivityDate="2023-09-23T18:23:20.847" Title="Can firecrackers be used to subside thunderstorms due to cumulonimbus clouds" Tags="|meteorology|clouds|" AnswerCount="0" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="25590" PostTypeId="2" ParentId="25588" CreationDate="2023-09-24T20:55:24.277" Score="5" Body="&lt;p&gt;In short, the issue is that we have no law of conservation of volume for mixing unequal components. The illustration is for macroscopic particles. It applies equally at the molecular to atomic scale.&lt;/p&gt;&#xA;&lt;p&gt;Imagine a set of 100 equally sized solid spheres. Pack them in a cubic arrangement. Now pack them in a close-packed arrangement. The volumes will be different.&lt;/p&gt;&#xA;&lt;p&gt;Imagine two sets of 100 spheres each, A and B. Pack them in different relative proportions, each always equaling 100 total spheres. By example 10 A + 90 B or 50 A + 50 B. The diagonal lines in the figure show the volumes in each set as you pick different numbers of spheres A and B. The sum is the topmost diagonal line. In the case of true conservation of volume, the total volume of the mixture will be the sum of the volumes of each set. The total volume will always follow the topmost diagonal line. As the particle mixture deviates from conservation of volume, the total volume of the mixture follows the individual lines rather than the total line.&lt;/p&gt;&#xA;&lt;p&gt;With the above in mind, the figure is stating that mixtures with large + small spheres follows more closely to total volume being controlled by each individual sphere sets. This is the greatest deviation from conservation of volume. Fundamentally, the smaller spheres intercalate within the larger spheres. As you make mixtures with more equally-sized spheres, they behave more closely to conservation of volume.&lt;/p&gt;&#xA;&lt;p&gt;Now, to appreciate the straight lines on the graph, consider that the discussion you quote talks about infinitely larger particles compared to the smaller particles. Infinitely larger is only possible when the size of the smallest particles is at some point allowed become zero volume. This is a &lt;em&gt;hypothetical&lt;/em&gt; state, not a real state. Even with the medium sized particles, they seem still to treat the ratio as infinitely larger at the limit of 100% of the smallest particles. Also note that a system with 100% fine particles is not shown as having zero volume, it is shown with a volume just greater than 100% course particles.&lt;/p&gt;&#xA;&lt;p&gt;So, start with the leftmost figure. As you add smaller particles you must remove larger particles &lt;em&gt;to keep some aspect of relative amounts (perhaps total number of particles) the same&lt;/em&gt;. This latter restriction on relative amounts must be explained din the source article. Hence, as you add smaller particles, the total volume decreases along a linear path as larger particles are removing more than smaller particles are adding back. At some point, the smaller particles become effective at increasing volume even though you are still removing larger particles. As the smaller particles become larger in size (right most figure), the point where they affect the volume change shifts to lower relative amount (shifts to the left on the graph. Also, the effect is less abrupt (the transition curve is smoother and further displaced from the two straight lines).&lt;/p&gt;&#xA;" OwnerUserId="13534" LastEditorUserId="13534" LastEditDate="2023-10-02T03:00:06.477" LastActivityDate="2023-10-02T03:00:06.477" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25595" PostTypeId="1" CreationDate="2023-09-27T18:56:26.777" Score="1" ViewCount="96" Body="&lt;p&gt;I'm interested in the physics/dynamics of a drop of water (2-5 mm dia) dropped from a height (terminal velocity is the limit) on smooth hydrophobic surfaces. Specifically the largest diameter of splattered droplets, height, number of droplets, etc.&lt;/p&gt;&#xA;&lt;p&gt;I have seen references to this with soil splatter and erosion from raindrops but I'm more interest in the dynamics of the drop itself.&lt;/p&gt;&#xA;" OwnerUserId="28036" LastEditorUserId="28036" LastEditDate="2023-09-28T00:27:10.770" LastActivityDate="2023-09-28T00:27:10.770" Title="Raindrop splash/splatter dynamics" Tags="|fluid-dynamics|erosion|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25596" PostTypeId="1" CreationDate="2023-09-28T20:53:46.040" Score="4" ViewCount="68" Body="&lt;p&gt;So because of Ekman transport, the middle of a gyre is slightly elevated. As a result water starts flowing down the pressure gradient. As it does so it is deflected by the coriolis force until the pressure gradient force and the coriolis effect balance each other out: this is called the geostrophic current.&lt;/p&gt;&#xA;&lt;p&gt;I'm reading in the book &amp;quot;The Earth System&amp;quot; by Kump et al. (2010) on p. 88 that this geostrophic current spirals &lt;em&gt;inwards&lt;/em&gt;. To be precise, Kump et al. say:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;In practice, the flow is a little less than 90° to the slope, so in fact the water tends to spiral inward as it moves around the gyre and the convergence in the gyre results in downwelling.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;My question: why does the geostrophic current spiral inwards?&lt;/p&gt;&#xA;&lt;p&gt;I know that geostrophic wind, when it experiences friction at the surface, also does not perfectly follow the isobars, but in this case the result is an effective flow &lt;em&gt;in the the same direction as the pressure gradient force&lt;/em&gt;, not in the opposite direction, as is suggested here.&lt;/p&gt;&#xA;" OwnerUserId="27611" LastEditorUserId="6298" LastEditDate="2023-09-29T06:21:58.023" LastActivityDate="2023-10-03T21:30:04.880" Title="Why does the geostrophic current spiraling around the slightly elevated middle of an oceanic gyre spiral inward?" Tags="|ocean-currents|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25597" PostTypeId="1" CreationDate="2023-09-29T08:28:31.557" Score="0" ViewCount="83" Body="&lt;p&gt;NASA has a land cover map that tells you what type of biome is on the Earth's surface:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://visibleearth.nasa.gov/images/61004/new-land-cover-classification-maps&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;There are 17 different land types. If you download one of the two tiffs here and zoom into a couple of places you'll see that some pixels are black. This ends up being a value of 254, whereas all the other values are 0 to 16, for the 17 different values. But the black pixels you see there have the value of 254. Would you happen to know what these are? And where would I be able to find out?&lt;/p&gt;&#xA;" OwnerUserId="13979" LastActivityDate="2023-09-29T08:28:31.557" Title="What does the value 254 mean on this map?" Tags="|mapping|land-surface|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25599" PostTypeId="1" CreationDate="2023-09-29T20:59:19.080" Score="2" ViewCount="33" Body="&lt;p&gt;I am trying to identify which stations within the NCEDC network are continuously recording ground motion, and which record only intermittently. I am using &lt;code&gt;obspy&lt;/code&gt;'s FDSN client to access station metadata and waveforms. Is there a way to do this without accessing the waveform data?&lt;/p&gt;&#xA;&lt;p&gt;For example, the station &lt;a href=&quot;https://ds.iris.edu/mda/NC/J032/?starttime=2009-11-25&amp;amp;endtime=3000-01-01&quot; rel=&quot;nofollow noreferrer&quot;&gt;NC.J032&lt;/a&gt; appears to record intermittently, as there was only 1 trace lasting about 3 minutes between 2023-01-01 and 2023-01-31. Is there some way I can figure this out using station metadata only, either using &lt;code&gt;obspy&lt;/code&gt; or through some other means?&lt;/p&gt;&#xA;" OwnerUserId="29730" LastActivityDate="2023-09-30T06:56:29.553" Title="Identifying continuously-recording seismic stations" Tags="|geophysics|seismology|data-analysis|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25600" PostTypeId="2" ParentId="25599" CreationDate="2023-09-30T06:56:29.553" Score="1" Body="&lt;p&gt;I think you can use WILBER3 by IRIS to find out more I'm not sure if that is what you need but give it a try. Also, have you tried retrieving the event data which got recorded by that station for whatever period of time the station is operating using Obspy get_events?&lt;/p&gt;&#xA;" OwnerUserId="26402" LastActivityDate="2023-09-30T06:56:29.553" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25601" PostTypeId="1" CreationDate="2023-09-30T19:58:46.507" Score="1" ViewCount="124" Body="&lt;p&gt;I am reading about the evolution of humans from ~2mya to today, and am running into some stuff on Geology like the &lt;a href=&quot;https://en.wikipedia.org/wiki/8.2-kiloyear_event&quot; rel=&quot;nofollow noreferrer&quot;&gt;8.2-kiloyear event&lt;/a&gt;, and other &amp;quot;cooling&amp;quot; events and warming events. I briefly saw something about &lt;a href=&quot;https://en.wikipedia.org/wiki/Axial_precession&quot; rel=&quot;nofollow noreferrer&quot;&gt;axial precession&lt;/a&gt;, but wasn't sure that was the main cause. I would imagine if it &lt;em&gt;was&lt;/em&gt; the main cause, like a spinning top sometimes the earth axis changes direction rapidly and that would mean different areas are further from or closer to the sun/moon, etc.. which would change their temperature and thus climate.&lt;/p&gt;&#xA;&lt;p&gt;So my layman question is, without having studied deeply all the various geological theory/background, what generally are the causes for the abrupt changes in climate/temperature for the past 10 million years? Is it solely the axial precession, or some other factors? If it is only mainly the axial precession, I'd be curious to know what &amp;quot;states&amp;quot; it can be in, how it occasionally abruptly transitions from hot to cold to hot to cold, etc..&lt;/p&gt;&#xA;&lt;p&gt;Basically I would just like to have a slightly better intuition for these things, not having a geology background.&lt;/p&gt;&#xA;" OwnerUserId="784" LastEditorUserId="784" LastEditDate="2023-09-30T20:04:12.540" LastActivityDate="2023-10-02T08:57:00.183" Title="What causes the rapid change in temperature / climate at various points in the past 10 million years, generally speaking?" Tags="|climate|temperature|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25602" PostTypeId="2" ParentId="25601" CreationDate="2023-10-01T02:28:36.153" Score="1" Body="&lt;p&gt;The mentioned &amp;quot;8.2ky event&amp;quot; was probably caused by a meltwater inflow surge or a change of meltwater inflow. Meltwater from parts of the thawing &lt;a href=&quot;https://en.wikipedia.org/wiki/Laurentide_Ice_Sheet&quot; rel=&quot;nofollow noreferrer&quot;&gt;Laurentide ice shield&lt;/a&gt; or a lake that formed or had oveflown, as written in the Wikipedia link. There is no link to &lt;a href=&quot;https://en.wikipedia.org/wiki/Milankovitch_cycles#Axial_precession&quot; rel=&quot;nofollow noreferrer&quot;&gt;earth's axial precession&lt;/a&gt;, which has a period of &lt;a href=&quot;https://climate.nasa.gov/news/2948/milankovitch-orbital-cycles-and-their-role-in-earths-climate/&quot; rel=&quot;nofollow noreferrer&quot;&gt;26,000 years&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;This inflow &lt;a href=&quot;https://www.nature.com/articles/s41598-021-84709-5&quot; rel=&quot;nofollow noreferrer&quot;&gt;suppressed the oceanic circulation&lt;/a&gt; in the North Atlantic. This thermohaline circulation is driven by &lt;a href=&quot;https://scied.ucar.edu/learning-zone/climate-change-impacts/melting-arctic-sea-ice-and-ocean-currents&quot; rel=&quot;nofollow noreferrer&quot;&gt;density differences&lt;/a&gt;, a sudden inflow of lesss dense fresh water at the spot of a main driver of that circulation would disturb that circulation, push it farther south or &lt;a href=&quot;https://www.metoffice.gov.uk/weather/learn-about/weather/oceans/amoc&quot; rel=&quot;nofollow noreferrer&quot;&gt;slow its overturning effect down&lt;/a&gt;, and thus influence the global heat distrubution, resulting in a cooling effect in the north.&lt;/p&gt;&#xA;&lt;p&gt;This cooling effect through temporarily suppressed heat distribution by density changes caused by the freshwater inflow was the probable cause of the 8.2ky cooling event.&lt;/p&gt;&#xA;&lt;p&gt;On a broader picture, during the 10 million years the &lt;a href=&quot;https://www.geomar.de/fileadmin/personal/fb1/p-oz/dnuernberg/Lehre_Skripte/FG_Fact_Sheet_engl.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;isthmus at Panama closes&lt;/a&gt;, thus changing global circulation and heat distribution, creating the golf stream and the &lt;a href=&quot;https://www.metoffice.gov.uk/weather/learn-about/weather/oceans/amoc&quot; rel=&quot;nofollow noreferrer&quot;&gt;AMOC&lt;/a&gt; and transporting moisture to the north, ice cap buildup in the north. Towards today, the Pleistocene, Milankovic cycles (of which axial precession is an element) take over control of the climate, as reflected in for example &lt;a href=&quot;https://upload.wikimedia.org/wikipedia/commons/7/77/Vostok_420ky_4curves_insolation.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;ice cores&lt;/a&gt; and sediment cores.&lt;/p&gt;&#xA;&lt;p&gt;So there is a lot going on the 10 million years.&lt;/p&gt;&#xA;" OwnerDisplayName="user29219" LastEditorDisplayName="user29219" LastEditDate="2023-10-02T08:57:00.183" LastActivityDate="2023-10-02T08:57:00.183" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25603" PostTypeId="1" CreationDate="2023-10-01T12:55:47.200" Score="4" ViewCount="1507" Body="&lt;p&gt;All of the literature at the heart of the current climate change debate talks about +1.5 degrees or +2.0 degrees above the pre-industrial average.&lt;/p&gt;&#xA;&lt;p&gt;I understand that, usually, &lt;em&gt;pre-industrial&lt;/em&gt; means 1850-1900 (as recorded by &lt;a href=&quot;https://www.ipcc.ch/sr15/faq/faq-chapter-1/&quot; rel=&quot;nofollow noreferrer&quot;&gt;the IPCC&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;This IPCC Special Report on Global Warming of 1.5°C uses the reference&#xA;period 1850–1900 to represent pre-industrial temperature. This is the&#xA;earliest period with near-global observations and is the reference&#xA;period used as an approximation of pre-industrial temperatures in the&#xA;IPCC Fifth Assessment Report.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I've tried to find a definition of exactly what temperature the pre-industrial average was in terms of degrees centigrade/Celsius - and exactly how that was determined/measured.&lt;/p&gt;&#xA;&lt;p&gt;Likewise, what is the current &lt;em&gt;absolute&lt;/em&gt; global-average temperature?  I can find plenty of deltas from an that unknown baseline, but am curious what the raw data shows.&lt;/p&gt;&#xA;" OwnerUserId="29739" LastActivityDate="2023-10-01T17:16:01.277" Title="What is the baseline temperature for the climate-change debate" Tags="|climate|temperature|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25604" PostTypeId="1" CreationDate="2023-10-01T14:34:54.973" Score="1" ViewCount="76" Body="&lt;p&gt;&lt;strong&gt;RH&lt;/strong&gt; is the symbol of relative humidity in many textbooks. But, in my experience, &lt;strong&gt;U&lt;/strong&gt; is often used in atmospheric measurements. For example, Vaisala PTU300 means pressure, temperature and humidity.&#xA;I think &lt;strong&gt;U&lt;/strong&gt; comes from h&lt;span class=&quot;math-container&quot;&gt;$u$&lt;/span&gt;midity, but this makes it curious why the symbol &lt;strong&gt;H&lt;/strong&gt; is used.&lt;/p&gt;&#xA;&lt;p&gt;Does anybody know, where the symbol &lt;strong&gt;U&lt;/strong&gt; come from in observation?&lt;/p&gt;&#xA;" OwnerUserId="29740" LastEditorUserId="2470" LastEditDate="2023-10-02T08:19:10.297" LastActivityDate="2023-11-05T11:39:58.757" Title="Why is U used for relative humidity in atmospheric measurement equipments?" Tags="|meteorology|atmosphere|earth-observation|humidity|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25605" PostTypeId="2" ParentId="25603" CreationDate="2023-10-01T17:16:01.277" Score="5" Body="&lt;p&gt;You have asked a very incisive and important question.  Nevertheless, the basic core of this question has been answered before, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/23139/1-5-above-what/23146#23146&quot;&gt;here&lt;/a&gt;. In sum, the determination is rather simple.  As summarized from NOAA in that answer -&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The 2020 global surface temperature was 1.76°F warmer than 57.0°F, which is 58.76°F. This temperature is 2.14°F warmer than the pre-industrial period (1880-1900). Consequently, the pre-industrial period temperature was 58.76°F - 2.14°F, or approximately 56.62°F (13.68°C).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The current average global temperature can be determined for any one year but is usually only an estimate based on the most recently assessed information.  The raw data consists of &lt;em&gt;substantially many hundreds of thousands&lt;/em&gt; of global sub-hourly/hourly/daily measurements from which the global average temperature is determined.  These measurements are taken, recorded, and reported, for many thousands of measurement sites on land, ships at sea, and aerial measurements by aircraft and balloons.  These data are adequately summarized for an average annual global surface temperature, and are available on the internet from the IPCC, British Met Office, NOAA, and others.  Although there may be slight differences in the time series presented by any particular entity (NOAA, for instance), these time series for the historic global average temperature are quite consistent and comparable.&lt;/p&gt;&#xA;&lt;p&gt;The pre-industrial temperature record is similarly assessed, based upon established meteorological sites and reported readings during the pre-1900 time period back to about 1850.  Keep in mind that as time recedes before 1900, land-based measurement sites become increasingly few and reported measurements increasingly sparse.  Hence, the average temperature for the pre-industrial period is established by statistical comparisons and adjustments for concurrent and comparable records later in the early 20th century.  Although the time series for these individual records forms the basis for determining the pre-industrial average temperature, the key word is average.  Consequently, as an average, the estimate is reasonably good because variations away from the average affect the outcome by a very small margin.&lt;/p&gt;&#xA;&lt;p&gt;As you have asked -&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;What is the baseline temperature for the climate-change debate...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;the answer is 13.68°C.&lt;/p&gt;&#xA;" OwnerUserId="29742" LastActivityDate="2023-10-01T17:16:01.277" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="25606" PostTypeId="1" AcceptedAnswerId="25610" CreationDate="2023-10-02T01:58:06.643" Score="3" ViewCount="150" Body="&lt;p&gt;Currently I am studying the period of oceanographic phenomena such as El Niño, and I have seen the next concepts: interannual, annual and intrannual and interseasonal, seasonal and intraseasonal. I can understand some of them, but I would like someone could help me to understand them very well  in the context of Oceanography.&#xA;Maybe if you provide me with some literature about those definitions it would be great? Thanks.&lt;/p&gt;&#xA;" OwnerUserId="27360" LastEditorDisplayName="user29219" LastEditDate="2023-10-03T02:31:11.780" LastActivityDate="2023-10-03T02:31:11.780" Title="What do interannual, annual and intrannual and interseasonal, seasonal and intraseasonal mean in the context of Oceanography?" Tags="|oceanography|sea-level|seasons|enso|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25607" PostTypeId="1" AcceptedAnswerId="25609" CreationDate="2023-10-02T08:07:21.200" Score="1" ViewCount="176" Body="&lt;p&gt;Found one publication &lt;a href=&quot;https://images.astronet.ru/pubd/2008/09/28/0001230856/195-213.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://images.astronet.ru/pubd/2008/09/28/0001230856/195-213.pdf&lt;/a&gt; &amp;quot;Deformations of the Earth's mantle due to core displacements&amp;quot;. In page 196. there are words &amp;quot;Using the above-mentioned Chinese results we have evaluated the velocity of the centre of the core of the Earth relative to the mantle centre as 8.0 cm year&amp;quot;. And in other places of the publication authors believe/confirms, that Earth's core is displaced.&lt;/p&gt;&#xA;&lt;p&gt;But i am trying to find more approval that Earth's core moved abnormally. Or to find basis to tell that Earth's core either does not move or moves in usual (normal) way. Found some more publications. Here &lt;a href=&quot;https://dornsife.usc.edu/news/stories/earths-inner-core-oscillates/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://dornsife.usc.edu/news/stories/earths-inner-core-oscillates/&lt;/a&gt;  writes about &amp;quot;six-year cycle&amp;quot;, so it would mean that Earth's core movement is normal process. From here &lt;a href=&quot;https://par.nsf.gov/servlets/purl/10417977&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://par.nsf.gov/servlets/purl/10417977&lt;/a&gt; i also understand that is is &amp;quot;usual&amp;quot; that Earth's core moves over time.&lt;/p&gt;&#xA;&lt;p&gt;The main question is whether since Year 1998 Earth's core moved abnormally? Do you know some &amp;quot;authoritative&amp;quot; publications / &amp;quot;proof&amp;quot;, &amp;quot;denial&amp;quot; of this?&lt;/p&gt;&#xA;&lt;p&gt;At the moment i found only Russian scientists' publications, that &amp;quot;proves&amp;quot; core displacement. And i can not find scientists from other countries, that &amp;quot;proves&amp;quot; it. Source is &lt;a href=&quot;http://vestnik.geospace.ru/index.php?id=569&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://vestnik.geospace.ru/index.php?id=569&lt;/a&gt; and at bottom of page is link to download pdf &lt;a href=&quot;http://vestnik.geospace.ru/php/download.php?id=UPLFa8f4af175cb6b43c89543e9dc24b4c71.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;http://vestnik.geospace.ru/php/download.php?id=UPLFa8f4af175cb6b43c89543e9dc24b4c71.pdf&lt;/a&gt;, page 9 bottom &amp;quot;Смещения ядра приводят к смещениям ЦМЗ по отношению к мантии&amp;quot; means like &amp;quot;Core displacements result in CentreOfEarthsMasses displacements relative to the mantle&amp;quot;. And in this video &lt;a href=&quot;https://youtu.be/ow2Dm-3SP24?t=5403&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://youtu.be/ow2Dm-3SP24?t=5403&lt;/a&gt; at 1:30:03 they tells about abnormal core displacement. Source again is Russian author &lt;a href=&quot;https://medcraveonline.com/PAIJ/PAIJ-02-00104.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://medcraveonline.com/PAIJ/PAIJ-02-00104.pdf&lt;/a&gt; And one more link &lt;a href=&quot;https://www.scirp.org/pdf/gep_2021020514133107.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.scirp.org/pdf/gep_2021020514133107.pdf&lt;/a&gt; (&amp;quot;northward drift of the Earth’score. &amp;quot;).&lt;/p&gt;&#xA;&lt;p&gt;As i understand scientists gets data about seismic waves, how long the waves goes through certain objects. And in such a way detects position of the Earth's core. And they somehow measures center of Earth's mass, using satellites. Where to get such data, and why, for example, some Russian scientists &amp;quot;proves&amp;quot; that Earth's core is displaced abnormally, but scientists from other countries &amp;quot;says&amp;quot; nothing. Could someone find errors in Russian scientists publications (calculations, examinations etc.)?&lt;/p&gt;&#xA;" OwnerUserId="29744" LastEditorUserId="29744" LastEditDate="2023-10-03T06:07:50.633" LastActivityDate="2023-10-03T06:52:01.253" Title="Is Earth's core displaced (abnormally changed its position)?" Tags="|core|" AnswerCount="1" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="25608" PostTypeId="2" ParentId="25604" CreationDate="2023-10-02T08:17:55.300" Score="1" Body="&lt;p&gt;Rarely are there standards when it come to using symbols in equations or abbreviations. Having tried Google Translate, Humidity in &lt;strong&gt;&lt;a href=&quot;https://translate.google.com/?sl=auto&amp;amp;tl=la&amp;amp;text=humidity&amp;amp;op=translate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Latin&lt;/a&gt;&lt;/strong&gt; is generally translated to humiditas, but &lt;em&gt;umor&lt;/em&gt; is also, apparently, well used  as a word for humidity, fluid &amp;amp; moisture in Latin.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-10-02T08:17:55.300" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25609" PostTypeId="2" ParentId="25607" CreationDate="2023-10-02T08:33:09.880" Score="3" Body="&lt;p&gt;Y. Barkin proposed that the inner core is displaced towards the north pole, I think to explain the slightly pear shaped form of the earth. But the earth is described as an &lt;a href=&quot;https://earthobservatory.nasa.gov/features/GRACE/page3.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;uneven oblate spheroid&lt;/a&gt;, with dynamic forces at work that change crust and mantle composition and densities causing anomalies in the earth's gravitational field. So I am not sure if that view of a displaced inner core is widely accepted.&lt;/p&gt;&#xA;&lt;p&gt;There are two different things in the question: Is the core displaced, or does it just spin differently than the rest of the earth's shells.&lt;/p&gt;&#xA;&lt;p&gt;Concentrating on the Science paper (second link in the question), they do not say that the core is displaced, if that means its center in relation to the center of the bulk of the earth. But its rotation &lt;strong&gt;oscillates&lt;/strong&gt;, explaining minuscule variations in the length of a day and &lt;a href=&quot;https://www.nature.com/articles/s41561-022-01112-z&quot; rel=&quot;nofollow noreferrer&quot;&gt;earth's magnetic field&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;So when they say &amp;quot;The earth's surface shifts in relation&amp;quot; they mean that they found out that the core rotates a bit faster and a bit slower in a six year period, making a point on the surface of the earth stay behind or be a bit in front of an imaginary point on the inner core's surface.&lt;/p&gt;&#xA;&lt;p&gt;This is different from a previous proposition that the inner core spins a bit faster than the outer shells of the earth, called &lt;a href=&quot;https://en.wikipedia.org/wiki/Inner_core_super-rotation&quot; rel=&quot;nofollow noreferrer&quot;&gt;inner core super rotation&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user29219" LastEditorDisplayName="user29219" LastEditDate="2023-10-03T06:52:01.253" LastActivityDate="2023-10-03T06:52:01.253" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25610" PostTypeId="2" ParentId="25606" CreationDate="2023-10-02T09:11:40.963" Score="2" Body="&lt;p&gt;I doubt there is literature, apart from dictionaries, it's simple semantics:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;interannual: from year to year&lt;/li&gt;&#xA;&lt;li&gt;annual: yearly&lt;/li&gt;&#xA;&lt;li&gt;intrannual: during the course of a year&lt;/li&gt;&#xA;&lt;li&gt;interseasonal: from season to season, or between seasons&lt;/li&gt;&#xA;&lt;li&gt;seasonal: during a season&lt;/li&gt;&#xA;&lt;li&gt;intraseasonal: during a season&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The seasonal stuff can depend on the context, as seasons fall differently over the surface of the earth. It also depends on context if someone is talking about a point in time, or a period, a punctual observation or a trend or development. These terms just help framing (that's a cool word) the subject at hand.&lt;/p&gt;&#xA;" OwnerDisplayName="user29219" LastActivityDate="2023-10-02T09:11:40.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25612" PostTypeId="2" ParentId="25588" CreationDate="2023-10-03T17:51:02.697" Score="1" Body="&lt;p&gt;This is meant as a supplement to Jeffrey Weimer's fine answer&lt;/p&gt;&#xA;&lt;p&gt;The apparent volume is based on the largest particle if the diameter ratios are large enough. If the smaller particle is much smaller (the diameter ratios in the graphs show  50.5 and 6.3) then it can occupy the space in-between the larger particles. If all the small particles fit then the apparent volume doesn't change. It will be the volume of the space occupied by the larger particles which is not the sum of the volumes of the larger particles.&lt;/p&gt;&#xA;&lt;p&gt;As a small thought experiment, fill a small box with tennis balls packed as efficiently as possible. The apparent volume is the volume of the box. The addition of sand won't alter the apparent volume (since it will settle in the empty space between tennis balls) until there is so much sand it overflows out of the box.&lt;/p&gt;&#xA;&lt;p&gt;Now (after the box is fully packed with tennis balls and sand) remove all of the tennis balls. The apparent volume of the remaining sand will be much less than the volume of the box.&lt;/p&gt;&#xA;" OwnerUserId="28036" LastEditorUserId="28036" LastEditDate="2023-10-03T18:28:47.113" LastActivityDate="2023-10-03T18:28:47.113" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25615" PostTypeId="1" CreationDate="2023-10-04T00:44:20.510" Score="11" ViewCount="3023" Body="&lt;p&gt;I wonder if this is even possible to know....&lt;/p&gt;&#xA;&lt;p&gt;Do geophysicists and geologists have even a 'theoretical' idea about how deep Earth's churning of its layers goes?&lt;/p&gt;&#xA;" OwnerUserId="20985" LastEditorUserId="2470" LastEditDate="2023-10-05T03:29:53.137" LastActivityDate="2023-10-05T03:29:53.137" Title="From how deep in the mantle has any rock ever been brought to the surface? Have scientists found anything they believe originated in the outer core?" Tags="|geology|geophysics|structural-geology|mantle|geologic-layers|" AnswerCount="2" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25616" PostTypeId="2" ParentId="25615" CreationDate="2023-10-04T05:06:10.640" Score="4" Body="&lt;p&gt;As far as I know the best estimate is &amp;quot;upper mantle&amp;quot; from &lt;a href=&quot;https://earthandsolarsystem.wordpress.com/2012/11/24/mantle-xenoliths-a-window-into-the-interior-of-the-earth/&quot; rel=&quot;nofollow noreferrer&quot;&gt;mantle xenoliths&lt;/a&gt; but that's not terribly specific. I am not sure if knowing more than that is possible right now.&lt;/p&gt;&#xA;" OwnerUserId="29758" LastActivityDate="2023-10-04T05:06:10.640" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25618" PostTypeId="1" AcceptedAnswerId="25619" CreationDate="2023-10-04T06:49:18.047" Score="4" ViewCount="174" Body="&lt;p&gt;The Earth's mantle, away from the occasional magma chamber, is solid. But it flows over time and so is described as &amp;quot;pliant&amp;quot;, &amp;quot;hot chocolate&amp;quot;, &amp;quot;toothpaste&amp;quot;, etc.&lt;/p&gt;&#xA;&lt;p&gt;Glaciers flow much faster. But ice is rigid, solid and brittle, reflected in words such as &amp;quot;hail&lt;em&gt;stone&lt;/em&gt;&amp;quot; and &amp;quot;on the rocks&amp;quot; (although above cryogenic temperatures it is much softer than most minerals).&lt;/p&gt;&#xA;&lt;p&gt;Would most of Earth's mantle material, &lt;em&gt;in situ&lt;/em&gt;, feel rigid like crustal rock? All the way from the upper mantle to the edge of core (extreme pressures counteracting the searing heat)? My (indestructible) hands are too impatient to sense deformations over geological time...&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt;&#xA;To clarify what (I think) the case is, based on the answer below:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Indeed, ice and most silicates (if in crystal form and not glass form) are brittle rocks all the way to their melting point &lt;em&gt;at low pressure&lt;/em&gt;. No &amp;quot;taffy&amp;quot;, &amp;quot;chocolate&amp;quot; etc. They get weaker as they get hotter, but always shatter under a hammer blow.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Both can flow slowly when near their melting point (glaciers). Flow happens in between crystal grains, as atoms re-arrange themselves to relieve the applied stress.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;At extremely high pressure we can still talk about &amp;quot;compressive strength&amp;quot; (and brittleness, etc) in terms of how much &lt;em&gt;difference&lt;/em&gt; in pressure the rock can take. We could in theory set up a hammer to strike the rock while the whole system is immersed in hot high-pressure helium. No voids could form in the material because of the pressure; it can only break from the surface by letting helium in, and even that isn't an instant process. This means the only choice under a heavy a hammer blow is to deform without breaking. &lt;em&gt;Not really &amp;quot;taffy&amp;quot; more like &amp;quot;blacksmith metal&amp;quot;.&lt;/em&gt; A Bingham plastic from miliseconds to years and a non-newtonain fluid on thousand or million year time-scales.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="8476" LastEditorUserId="8476" LastEditDate="2023-10-22T00:28:48.563" LastActivityDate="2023-10-22T00:28:48.563" Title="Is it inaccurate to describe Earth's mantle as &quot;soft and plastic&quot;?" Tags="|plate-tectonics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25619" PostTypeId="2" ParentId="25618" CreationDate="2023-10-04T07:57:56.153" Score="3" Body="&lt;p&gt;Though the mantle is not homogeneous, it is overwhelmingly solid and convects as a rigid body. But partial melting can happen, under mid ocean ridges, in subduction zones or over hot spots. Just very little partial melt already change the viscosity by much by &amp;quot;greasing&amp;quot; the contacts between minerals.&lt;/p&gt;&#xA;&lt;p&gt;One can say it is &amp;quot;plastic&amp;quot;, and there may even happen toothpaste like effects (thixotropy = melt under stress), but the correct term is ductile = &amp;quot;smithable&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;I can't say what it &amp;quot;feels like&amp;quot;, but maybe give some visual impressions of what ductile means:&lt;/p&gt;&#xA;&lt;p&gt;In this &lt;a href=&quot;https://www.youtube.com/watch?v=TH9eLtU9QC0&quot; rel=&quot;nofollow noreferrer&quot;&gt;video&lt;/a&gt;, at 11:06 they show 4 cylinders of a rock that was exposed to a longitudinal compressing stress. It shows brittle deformation when the pressure of the environment is low, and ductile deformation when the environmental pressure is that of a depth of 30km.&lt;/p&gt;&#xA;&lt;p&gt;Now 30km is not mantle everywhere on earth, and the material is a sample from continental crust (marble, a metamorphic rock), but I think one gets the impression that pressure alone is enough to make rocks start to move.&lt;/p&gt;&#xA;&lt;p&gt;Given enough time, some rocks even deform under surface conditions.&lt;/p&gt;&#xA;&lt;p&gt;Further reading:&#xA;&lt;a href=&quot;https://opentextbc.ca/physicalgeologyh5p/chapter/stress-and-strain/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://opentextbc.ca/physicalgeologyh5p/chapter/stress-and-strain/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user29219" LastEditorDisplayName="user29219" LastEditDate="2023-10-04T08:05:39.393" LastActivityDate="2023-10-04T08:05:39.393" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25620" PostTypeId="1" CreationDate="2023-10-04T13:24:16.050" Score="1" ViewCount="276" Body="&lt;p&gt;While looking for atmospheric data in CMIP6, I came across two Table entries: &lt;code&gt;Amon&lt;/code&gt; and &lt;code&gt;Emon&lt;/code&gt;, both seem to contain monthly-mean atmospheric data. For Example, the following two datasets are the same except for the Table ID:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;code&gt;CMIP6.HighResMIP.EC-Earth-Consortium.EC-Earth3P-HR.hist-1950.r1i1p2f1.Amon.ta.gr&lt;/code&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;code&gt;CMIP6.HighResMIP.EC-Earth-Consortium.EC-Earth3P-HR.hist-1950.r1i1p2f1.Emon.ta.gr&lt;/code&gt;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;The documentation doesn't mention much about the differences between those two Table IDs except that &lt;code&gt;Amon&lt;/code&gt; is &lt;em&gt;Monthly atmospheric data&lt;/em&gt; and that &lt;code&gt;Emon&lt;/code&gt; is &lt;em&gt;Monthly (time mean, extension)&lt;/em&gt;. After some searching, it seems that &lt;code&gt;Emon&lt;/code&gt; has more vertical levels (27 as opposed to 19 in &lt;code&gt;Amon&lt;/code&gt;).&#xA;I would like to if there are any other differences between these to Table IDs other than the difference the number of vertical levels?&lt;/p&gt;&#xA;" OwnerUserId="9633" LastActivityDate="2023-10-13T09:57:56.697" Title="What are the differences between 'Amon' and 'Emon' Table IDs in CMIP6?" Tags="|climate-models|climate-data|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25621" PostTypeId="2" ParentId="25615" CreationDate="2023-10-04T15:36:11.217" Score="5" Body="&lt;p&gt;Diamond is stable at high temperatures only under very high pressures. Mineral inclusions in a diamond, and the rocks in which a diamond are embedded, can offer further clues as to the depth from which the diamond came.&lt;/p&gt;&#xA;&lt;p&gt;The &lt;a href=&quot;https://en.wikipedia.org/wiki/Diamond#Geology&quot; rel=&quot;noreferrer&quot;&gt;Wikipedia article on diamond&lt;/a&gt; claims &amp;quot;A smaller fraction of diamonds (about 150 have been studied) come from depths of 330–660 km, a region that includes the transition zone. They formed in eclogite but are distinguished from diamonds of shallower origin by inclusions of majorite (a form of garnet with excess silicon). A similar proportion of diamonds comes from the &lt;strong&gt;lower mantle at depths between 660 and 800 km.&lt;/strong&gt; [20]&amp;quot; (my emphasis)&lt;/p&gt;&#xA;" OwnerUserId="18495" LastEditorUserId="18495" LastEditDate="2023-10-04T15:41:46.240" LastActivityDate="2023-10-04T15:41:46.240" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25622" PostTypeId="1" CreationDate="2023-10-05T04:24:55.753" Score="1" ViewCount="34" Body="&lt;p&gt;Is there a way to provide  data from Sentinel-5P for the air quality of Saudi Arabia for years 2018 and 2019 in an Excel spreadsheet.&lt;/p&gt;&#xA;" OwnerUserId="29767" LastEditorUserId="26841" LastEditDate="2023-10-16T08:40:51.933" LastActivityDate="2023-10-16T08:40:51.933" Title="Getting historic Sentinel-5P air quality data for Saudi Arabia" Tags="|air-quality|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25623" PostTypeId="2" ParentId="25579" CreationDate="2023-10-05T14:16:43.013" Score="1" Body="&lt;p&gt;Your post has multiple questions. Here are a few comments.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;If the device does indeed count particles, how does it convert that to mass?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Conversion from particles per volume (a number density &lt;span class=&quot;math-container&quot;&gt;$\rho_N$&lt;/span&gt; in units  m&lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt;) to mass per volume &lt;span class=&quot;math-container&quot;&gt;$\rho$&lt;/span&gt; (kg/m&lt;span class=&quot;math-container&quot;&gt;$^3$&lt;/span&gt;) requires knowing a mass per particle. One possible approach to estimate this value is to assume that particles have a specific, consistent size (e.g. diameter), shape (e.g. spherical), and mass density. Optical sensing methods are sensitive to particle size, and making a nominal assumption of specific gravity &lt;span class=&quot;math-container&quot;&gt;$= 1$&lt;/span&gt; will provide what is needed.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Is the health concern of breathing small particulates in a particular size category based on the total mass of them inhaled or the quantity of them?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Particle size determines where the particles get stuck in the nasal passage on the way to the lungs. Smaller particles are more damaging. Presuming that optical devices measure based on particle size, knowing the mass per volume at that size will be proportional to knowing the number of particles per volume.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Intuitively, I would have expected the measurements to be presented in parts per million ...&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Just FYI, the scale ppm (and ppb, ppt) has units mass per total mass.&lt;/p&gt;&#xA;" OwnerUserId="13534" LastActivityDate="2023-10-05T14:16:43.013" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25625" PostTypeId="2" ParentId="25579" CreationDate="2023-10-06T02:23:45.453" Score="3" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Why are particulate matter measurements (like PM2.5) from an air quality monitor given in micrograms per cubic meter (μg / mm^3)?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The fundamental measurement for particulate matter is done using a filter.  You pull in a known volume of air over a known period of time, and then you measure the mass of the filter before and afterwards.  This allows you to calculate mass per volume (on whatever time average you choose).  This method is the most accurate way to measure particulate matter and is the federal reference method for determining attainment of federal air quality PM standards.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;I assume the device is using an optical system to count particles in a sample volume the air, and extrapolating as necessary to a standard volume like a cubic meter.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;While these devices do exist (particle counters like purple air sensors) they don't measure mass directly and are incredibly dependent on the mass per particle assumptions.  There are also light scattering &lt;a href=&quot;https://gml.noaa.gov/aero/instrumentation/neph_desc.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;nephelometers&lt;/a&gt; that are more accurate than a particle counter, but they don't measure mass directly either.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;If the device does indeed count particles, how does it convert that to mass? Is the mass of 2.5 micron particles suspended in air consistent enough that multiplying the count by the average mass yields a good estimate?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;No it's not consistent enough, and the inference is incredibly dependent on the type of PM you assume you are measuring.  For instance, if you are measuring 1 million dust particles, it will be far heavier than 1 million smoke particles, and the particle counter won't know the difference.  But, they do it anyway.  For a nephelometer, best practice is to co-locate a nephelometer with a filter-based monitor so that you can build a correlation relationship that is appropriate for the PM sources in that region.  However, when PM emission source profiles change (e.g. a wildfire smoke event becomes more prominent than local sources) the correlation is no longer valid and thus reported concentrations are erroneous.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Is a correction factor for air pressure applied to account for the fact that heavier particles are more likely to settle out of suspension when the air pressure drops? (My particular monitor does not report air pressure, but I suppose it might still monitor it.)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Air pressure doesn't change due to suspended particulate matter, but air pressure is an important variable because in order to report consistent data you need to account for temperature and pressure to standardize your air volume to STP (or similar).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Is the health concern of breathing small particulates in a particular size category based on the total mass of them inhaled or the quantity of them?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The smaller the particles, the deeper they go into your lungs when you breathe them.  So, for instance, ultrafine particles (PM1.0) are a bigger health concern than fine particles (PM2.5), which are more of a health concern than coarse particles (e.g. PM10 - minus PM2.5).  All health based standards for particulate matter are based on mass concentrations.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Intuitively, I would have expected the measurements to be presented in parts per million or as a count of particles per volume, not only because of how (I assume) it's measured, but also because of the utility.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This is how gaseous measurements are reported.  Individual gases do not have different sizes because they represent a certain molecules.  Particulate matter can be many different molecules with different sizes.  Furthermore, particulate matter is in solid or liquid form, while gases are not.  And, gases are not measured using filters (which can be weighed) because they do not collect onto a filter.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2023-10-06T02:23:45.453" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25626" PostTypeId="2" ParentId="23329" CreationDate="2023-10-06T12:34:46.837" Score="1" Body="&lt;p&gt;This is a partial answer to the &amp;quot;how can it be predicted&amp;quot; part of the question. A new paper (&lt;a href=&quot;https://doi.org/10.1016/j.epsl.2023.118323&quot; rel=&quot;nofollow noreferrer&quot;&gt;Duputel et al., 2023&lt;/a&gt;) shows how Very-Long-Period (VLP) seismic events can be used to infer the end of an eruption at Piton de la Fournaise (and probably at other volcanoes).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;For all eruptions between 2014 and 2015 at Piton de la Fournaise, VLP events were detected primarily when the lava extrusion rate is rapidly decreasing (Fig. S30). This is particularly evident for the three later VLP swarms of the August-October 2015 eruptions, which systematically occurred before sudden drops in lava emissions. These swarms were accompanied by rapid summit deflations (Fig. 3), corresponding to the contraction of the dike above the shallow reservoir (see Fig. S20 and Fig. S22). Although the excitation process of the dike resonance is currently unknown, this suggests that VLP events are associated with rapid pressure variations in the volcano plumbing system. The detection of VLP events is therefore useful for monitoring purposes because they indicate changes in the magma flow that may lead to a permanent or temporary cessation of lava emissions.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The introduction also mentions another method currently used, that is the near real time eruption rate which is measured by satellites, but it comes with its own challenges:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Despite advances in volcano monitoring, it is currently difficult to forecast when an eruption will end. [...] Magma discharge rate can be quantified in near real time from satellite data and volcanic tremor amplitude (Coppola et al., 2009; Hibert et al., 2015). Using such observations, it is possible to predict the end date of eruptions by assuming that they are fed by a single magma reservoir releasing its elastic strain energy as it re-equilibrates with the lithostatic pressure (Bonny and Wright, 2017; Wadge, 1981). Although such forecast performs well for short lived eruptions at Piton de la Fournaise (Bonny and Wright, 2017), it does not work for longer eruptions that are associated with more complicated time-evolutions (Coppola et al., 2009).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2023-10-06T12:34:46.837" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25629" PostTypeId="1" AcceptedAnswerId="25632" CreationDate="2023-10-07T01:42:24.460" Score="3" ViewCount="115" Body="&lt;p&gt;This graph presents an estimate of Phanerozoic CO&lt;sub&gt;2&lt;/sub&gt; levels on Earth.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/HgCTn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HgCTn.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;From the onset of the graph, it appears that CO&lt;sub&gt;2&lt;/sub&gt; levels are rising. However, I've come across papers, such as &lt;a href=&quot;https://pubmed.ncbi.nlm.nih.gov/13679912/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this one&lt;/a&gt;, suggesting that Proterozoic CO&lt;sub&gt;2&lt;/sub&gt; levels were higher than those in the Phanerozoic.&lt;/p&gt;&#xA;&lt;p&gt;I'm seeking a summary of how multicellular life has influenced Earth's CO&lt;sub&gt;2&lt;/sub&gt; levels to better understand our planet. I recognize that this topic is vast and could span an entire book. So, to narrow it down:&lt;/p&gt;&#xA;&lt;p&gt;I understand that both foraminifera and other unicellular and multicellular organisms have been storing CO&lt;sub&gt;2&lt;/sub&gt; since the beginning of the Phanerozoic.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, multicellular organisms, especially plants, have acted as CO&lt;sub&gt;2&lt;/sub&gt; sinks. This began during the Devonian-Carboniferous period. However, data suggests a declining CO&lt;sub&gt;2&lt;/sub&gt; trend since the Cambrian. This leads me to believe that the decrease in atmospheric CO&lt;sub&gt;2&lt;/sub&gt; throughout half of the Phanerozoic might be mainly attributed to shell-forming organisms. This brings me to a central question:&lt;/p&gt;&#xA;&lt;p&gt;Which organisms have removed more CO&lt;sub&gt;2&lt;/sub&gt; in Phanerozoic and in total Earth's history, plants or shell organisms?&lt;/p&gt;&#xA;&lt;p&gt;Additionally, I'd appreciate it if you could answer &lt;a href=&quot;https://earthscience.stackexchange.com/questions/25541/interpretation-of-phanerozoic-co2-levels-graph&quot;&gt;this other related question I've posted with a bounty&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerDisplayName="user29779" LastEditorDisplayName="user29779" LastEditDate="2023-11-25T16:47:46.690" LastActivityDate="2023-11-25T16:47:46.690" Title="Pre-Phanerozoic CO2 levels and pluricell life influence in C Earth's cycle" Tags="|geology|planetary-science|carbon-cycle|geobiology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25630" PostTypeId="1" CreationDate="2023-10-07T07:10:28.757" Score="1" ViewCount="50" Body="&lt;p&gt;I am currently competing in a case study competition a part of which has asked us to estimate the amount of Nd, Pr, and Dy in the SUAC complex (&lt;a href=&quot;https://www.researchgate.net/publication/264791627_REE_mineralization_in_the_carbonatites_of_the_Sung_Valley_Ultramafic-Alkaline-Carbonatite_Complex_Meghalaya_India&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sung Valley Ultramafic-Alkaline-Carbonatite&lt;/a&gt;) in electric vehicle or wind turbine equivalents.&lt;/p&gt;&#xA;&lt;p&gt;I recently read a report on the surface exploration of the carbonatite bodies in the area and while they've given the width, length and concentration of these elements within the carbonatite bodies but they haven't given the depth.&lt;/p&gt;&#xA;&lt;p&gt;I was wondering as to how I would calculate the amount of those REEs with the given data. Any help would be appreciated.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;The part of the case study mentioned for your reference:&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Using publicly available data on the amount of REE contained within the Sung&#xA;Hill carbonatite, and estimates on the amount of specific elements required for&#xA;various magnets used in electric vehicle motors and wind power turbines,&#xA;estimate an “electric vehicle equivalent” and a “wind power turbine equivalent”&#xA;if the currently known REE resource at Sung Hill would be extracted to&#xA;completion.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="29783" LastEditorUserId="6298" LastEditDate="2023-10-08T20:59:25.013" LastActivityDate="2023-10-08T20:59:25.013" Title="Estimation of rare earth elements in the SUAC complex" Tags="|geology|geochemistry|mineralogy|petrology|rare-earth|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25631" PostTypeId="1" CreationDate="2023-10-07T10:43:43.157" Score="2" ViewCount="31" Body="&lt;p&gt;I am hoping to walk from Trabzon to Astara during October and November. I am hoping to take the route that will have the highest &amp;quot;average low&amp;quot; temperature across this period, to make camping more comfortable.&lt;/p&gt;&#xA;&lt;p&gt;I have all the temperature charts for the cities in the region from Wikipedia. However it would be better to have maps showing similar data (for each month, or even better each week), as Wikipedia's city charts don't do enough to reveal strips of warm climates in rural areas eg along Lake Van or along Lake Urmia, or along the Aras river valley.&lt;/p&gt;&#xA;&lt;p&gt;Is there any online map of average low temperatures for each month or week of the year which I can use?&lt;/p&gt;&#xA;" OwnerUserId="26584" LastActivityDate="2023-10-10T08:36:38.083" Title="Map showing monthly or weekly average low temperatures in Turkey and Iran" Tags="|climate|temperature|mapping|seasons|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25632" PostTypeId="2" ParentId="25629" CreationDate="2023-10-07T14:51:44.327" Score="2" Body="&lt;p&gt;It changes, there is no one overwhelming effect.&lt;/p&gt;&#xA;&lt;p&gt;At some times plants have dominated at others ocean sediments have dominated.&#xA;Position of continents, global temperature, sea level, and evolution of lifeforms all effect it.&lt;/p&gt;&#xA;&lt;p&gt;Also you have a problem that those time periods are time PERIODS, the Proterozoic is 5 times longer than the phanerozoic. It had higher AND lower levels.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://rock.geosociety.org/net/gsatoday/archive/9/11/pdf/i1052-5173-9-11-1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://rock.geosociety.org/net/gsatoday/archive/9/11/pdf/i1052-5173-9-11-1.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earthscience.rice.edu/wp-content/uploads/2017/08/Berner_nature-2003-1.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earthscience.rice.edu/wp-content/uploads/2017/08/Berner_nature-2003-1.pdf&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S1342937X18302818&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/S1342937X18302818&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2023-10-12T22:03:45.417" LastActivityDate="2023-10-12T22:03:45.417" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25633" PostTypeId="1" AcceptedAnswerId="25636" CreationDate="2023-10-07T15:18:43.373" Score="3" ViewCount="96" Body="&lt;p&gt;We understand that the Hadean Earth was basically a giant ball of magma, constantly bombarded, no atmosphere, and solidified material never accumulated as Earth was too hot at its surface. We know from the magma that eventually crust formed, and oceans began to form from comet/asteroid bombardment, as well as from volcanic degassing.&lt;/p&gt;&#xA;&lt;p&gt;...However, Hadean Earth formed after tens of millions of years as gas and dust accumulated to form the planet, &lt;strong&gt;but what even is meant by &amp;quot;gas and dust&amp;quot;?&lt;/strong&gt; When I think of those terms I think of our atmosphere and smog, and dust that would be in the corner of the house. How can it account for all the elements that occur naturally on Earth? It seems as if Earth was created from something that would have no grounds creating Earth. Is a certain temperature implied when &amp;quot;gas and dust&amp;quot; is stated? The dust in the corner of the house can not become magma.&lt;/p&gt;&#xA;&lt;p&gt;I know my hypothesizing is absurd, but I am doing that on purpose: what is even meant by &amp;quot;gas and dust&amp;quot;? What should be invoked in my mind, since mundane examples are not sufficient?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit:&lt;/strong&gt; I was led to this question through studying Geologic Time and its eras; if this would better fit in another stack exchange like astronomy, sorry for confusion.&lt;/p&gt;&#xA;" OwnerUserId="29777" LastEditorUserId="29777" LastEditDate="2023-10-07T16:11:20.550" LastActivityDate="2023-10-10T19:03:32.220" Title="How did &quot;dust and gas&quot; form into the Hadean Earth?" Tags="|earth-history|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25634" PostTypeId="1" CreationDate="2023-10-07T18:45:29.753" Score="3" ViewCount="74" Body="&lt;p&gt;I was researching solar insolation and found that solar insolation at the poles over summer is roughly equivalent to several places on earth that have relatively warm summers. Below is a Matlab graph showing the average insolation received by Fairbanks, Chicago, and the North Pole between June 1st - August 31. The only contradictory thing I can think of is that I calculated Solar Insolation, and not Direct insolation. Direct Insolation accounts for the length in the atmosphere that radiation has to travel through before reaching the surface, but attempting to graph it using the equation &lt;a href=&quot;https://i.stack.imgur.com/9HbYT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9HbYT.png&quot; alt=&quot;Equation&quot; /&gt;&lt;/a&gt; from &lt;a href=&quot;https://en.wikipedia.org/wiki/Direct_insolation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; resulted in the graph labeled &amp;quot;Direct Insolation Example&amp;quot;, which appears to be incorrect. In any case, that effect seems to be relatively minor. The only major difference that I can think of between the summer climate characteristics of the cities and the north pole is that the north pole is oceanic, and thus has to deal with the very high thermal inertia of the very cold water surrounding it, making it unable to have warm summers despite similar solar insolation. In addition, I understand ice has a higher Albedo than land, and thus the actual amount of energy received is lessened. However, how is that fundamentally different than locations with thick snowpack that eventually melts over the summer?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Chicago#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Chicago Avg Summer Temp&lt;/a&gt; - 73.3&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Fairbanks,_Alaska#Climate&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fairbanks Avg Summer Temp&lt;/a&gt; - 60.3&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/North_Pole#Climate,_sea_ice_at_North_Pole&quot; rel=&quot;nofollow noreferrer&quot;&gt;North Pole Avg Summer Temp&lt;/a&gt; - 32&#xA;&lt;a href=&quot;https://i.stack.imgur.com/vz4uo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vz4uo.png&quot; alt=&quot;&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/qRhHI.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qRhHI.png&quot; alt=&quot;&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Also a few related relevant questions.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Why does the North Pole have slightly warmer winters than extremely continental climates like Yakutsk? The difference isn't huge, but it's still odd considering that the poles should be surrounded by ice (Which should act like ground in terms of continentality) in the winter.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;" OwnerUserId="29681" LastActivityDate="2023-10-07T18:45:29.753" Title="Would the North Pole have a continental climate with warm summers if it was surrounded by land?" Tags="|climate|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25636" PostTypeId="2" ParentId="25633" CreationDate="2023-10-10T01:33:40.353" Score="3" Body="&lt;p&gt;Very simply. No disrespect, but this is the type of explanation aimed at a young elementary/primary school child.&lt;/p&gt;&#xA;&lt;p&gt;It starts with &lt;a href=&quot;https://en.wikipedia.org/wiki/Hydrogen&quot; rel=&quot;nofollow noreferrer&quot;&gt;hydrogen&lt;/a&gt;, helium and lithium . They've been around since the &lt;a href=&quot;https://en.wikipedia.org/wiki/Big_Bang&quot; rel=&quot;nofollow noreferrer&quot;&gt;Big Bang&lt;/a&gt;. &lt;a href=&quot;https://en.wikipedia.org/wiki/Quantum_fluctuation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Quantum fluctuations&lt;/a&gt; created random zones of differing density material within the early universe. This resulted in some hydrogen collapsing under gravity to form stars. When enough hydrogen was collected, the interior of the stars became very hot and started to fuse hydrogen into different elements. First to be created within the stars, under &lt;a href=&quot;https://en.wikipedia.org/wiki/Stellar_nucleosynthesis&quot; rel=&quot;nofollow noreferrer&quot;&gt;stellar nucleosynthesis&lt;/a&gt;, also known as stellar nuclear fusion, was more helium. As hydrogen became depleted within the star, the heavier elements began to be created under nuclear fusion.&lt;/p&gt;&#xA;&lt;p&gt;Within stars similar to the Sun, this process ends with the formation of iron, shortly before the star sheds its outer layers explodes; larger stars explode as &lt;a href=&quot;https://en.wikipedia.org/wiki/Supernova&quot; rel=&quot;nofollow noreferrer&quot;&gt;supernovae&lt;/a&gt;. The formation of elements heavier (see the &lt;a href=&quot;https://en.wikipedia.org/wiki/Periodic_table&quot; rel=&quot;nofollow noreferrer&quot;&gt;periodic table of elements&lt;/a&gt;) than iron results from an alternate process, such as merging neutron stars, which I'll let you to investigate -  I'm keeping things as simple as possible.&lt;/p&gt;&#xA;&lt;p&gt;As the stars explode during a supernova event they disperse the elements they made (He, B, C, O, N, F, Ne, Na, Mg, Al, Si, P, S, Cl Ar, K, Ca, ... Fe) into the nearby cosmos. From this clouds of gas, or gases (oxygen and nitrogen, etc.). The metallic elements are the precursors of &lt;a href=&quot;https://en.wikipedia.org/wiki/Cosmic_dust#Some_%22dusty%22_clouds_in_the_universe&quot; rel=&quot;nofollow noreferrer&quot;&gt;cosmic dust&lt;/a&gt;. These coalesce under gravity to form larger grains, which in turn coalesce under gravity to form larger particles. Eventually rocks are formed, similar to what is found in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Asteroid_belt&quot; rel=&quot;nofollow noreferrer&quot;&gt;asteroid belt&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Either via the influence of gravity or motion induced collisions, such materials start to coalesce further to form planets, or the cores or planets that later become gas giants.&lt;/p&gt;&#xA;&lt;p&gt;Each collision produces heat. This along with the heat from decaying nuclear isotopes makes the planets hot enough to become molten. Again, under gravity the heavier elements coalesce towards the center of the planet.&#xA;The heat and the molten nature of the planet results in the formation of various compounds. As the outer parts of the planet cools solid crystals precipitate out of the molten mass to form solid rock that creates the crust of the planet.&lt;/p&gt;&#xA;&lt;p&gt;Due to the molten nature of some of the rock, as the planet cools, volcanic activity continues, bring fresher molten material to the surface of the planet. It also release volcanic gases, such as carbon dioxide, to form the initial atmosphere of the planet (see Venus, Earth and Mars).&lt;/p&gt;&#xA;&lt;p&gt;While all this is going on, the planet will be bombarded by asteroids and comets which bring additional material to the surface of the planet, such as heavy metals and water. This essentially is the Hadean Earth.&lt;/p&gt;&#xA;&lt;p&gt;Later if life forms, such a &lt;a href=&quot;https://en.wikipedia.org/wiki/Cyanobacteria&quot; rel=&quot;nofollow noreferrer&quot;&gt;cyanobacteria&lt;/a&gt; and conditions are favorable, carbon dioxide from the atmosphere will be consumed and oxygen, created by the bacteria, will accumulate in the atmosphere. Having a protective planetary magnetic field helps with retention of the planetary atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2023-10-10T19:03:32.220" LastActivityDate="2023-10-10T19:03:32.220" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25637" PostTypeId="2" ParentId="25631" CreationDate="2023-10-10T08:36:38.083" Score="1" Body="&lt;p&gt;What you are referring to are &lt;em&gt;climate maps&lt;/em&gt;, which show average weather values over a 30 year period. Weather forecasters will often then look at '&lt;a href=&quot;https://www.ncei.noaa.gov/access/monitoring/dyk/anomalies-vs-temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;anomaly&lt;/a&gt;' maps which show how current conditions vary compared with the 30-year average.&lt;/p&gt;&#xA;&lt;p&gt;Both these terms will help you find what you are looking for.&lt;/p&gt;&#xA;&lt;p&gt;A quick search found &lt;a href=&quot;https://climatemaps.romgens.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;climatemaps.romgens.com/&lt;/a&gt;, but there will be others which show the same information, perhaps in a more useful format. The website I've linked to defaults to precipitation and you have to change the variable to '&lt;em&gt;Min. temperature&lt;/em&gt;' and then choose the month you are interested in.&lt;/p&gt;&#xA;&lt;p&gt;I also found a Turkey-specific map on Word Bank Group's &lt;a href=&quot;https://climateknowledgeportal.worldbank.org/country/turkiye/climate-data-historical&quot; rel=&quot;nofollow noreferrer&quot;&gt;Climate Knowledge Portal&lt;/a&gt;. Again, you will need to change the variable to '&lt;em&gt;average minimum surface air temperature&lt;/em&gt;' and choose the months you are interested in.&lt;/p&gt;&#xA;&lt;p&gt;Bear in mind that the thirty-year averages are for distinct periods defined by the World Meteorology Organisation. The latest one is 1991-2020, but the past few years have on average been warmer than that period. Any results you find are likely to be showing slightly cooler conditions than you will get on average these days, but climate is different to weather and the weather could be significantly warmer or colder. All you are doing is weighing the odds in your favour.&lt;/p&gt;&#xA;&lt;p&gt;Have a great trip.&lt;/p&gt;&#xA;" OwnerUserId="20542" LastActivityDate="2023-10-10T08:36:38.083" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25638" PostTypeId="1" CreationDate="2023-10-10T09:52:44.087" Score="1" ViewCount="84" Body="&lt;p&gt;I am currently working on a research project regarding climate sensitivities of plant species and I need to analyze future climate data. Worldclim.org has a broad spectrum of climate data based on current global climate models. I want to analyze the data using GIS applications such as ArcGIS Pro and QGIS as well as R.&lt;/p&gt;&#xA;&lt;p&gt;However one particular dataset I need to analyze (MPI-ESM 1.2 HR with 30 seconds spatial resolutuion for SSP5-8.5) seems to be completely empty. All cells have &amp;quot;no data&amp;quot; assigned to them. The dataset is still 2GB large as it covers the whole earth. All the other datasets I looked at are somewhat larger (e.g. 8-10 GB) and work fine. Is there something obvious I am missing or is the data indeed faulty?&lt;/p&gt;&#xA;&lt;p&gt;I tried contacting the people at worldclim.org regarding this issue a few weeks ago but I got no response as of today.&lt;/p&gt;&#xA;&lt;p&gt;Worldclim.org:&#xA;&lt;a href=&quot;https://worldclim.org/data/cmip6/cmip6climate.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://worldclim.org/data/cmip6/cmip6climate.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Download Link of the faulty dataset:&#xA;&lt;a href=&quot;https://geodata.ucdavis.edu/cmip6/30s/MPI-ESM1-2-HR/ssp585/wc2.1_30s_bioc_MPI-ESM1-2-HR_ssp585_2061-2080.tif&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://geodata.ucdavis.edu/cmip6/30s/MPI-ESM1-2-HR/ssp585/wc2.1_30s_bioc_MPI-ESM1-2-HR_ssp585_2061-2080.tif&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Has anyone experienced a similar issue or knows an alternative source for the same data?&lt;/p&gt;&#xA;" OwnerUserId="29792" LastActivityDate="2023-12-29T13:00:03.667" Title="Faulty dataset on Worldclim.org" Tags="|climate-models|open-data|gis|climate-data|r|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25639" PostTypeId="1" CreationDate="2023-10-10T21:29:45.847" Score="1" ViewCount="18" Body="&lt;p&gt;I would like to calculate the demand for biofertilizer for 5 farms based on their size. The farms have the following sizes: 50, 70, 90, 100, and 120 hectares (ha). Is it possible to estimate this value? I believe we need to assume a rate of application per hectare, correct? This average fertilizer application rate can vary depending on the type of crops, soil conditions, and other agronomic factors. However, I have no information about the farms other than their size. Any ideas on how to calculate this?&lt;/p&gt;&#xA;&lt;p&gt;Thank you very much!&lt;/p&gt;&#xA;" OwnerUserId="29795" LastActivityDate="2023-10-10T21:29:45.847" Title="How to calculate the biofertilizer demand of a farm?" Tags="|agriculture|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25640" PostTypeId="1" CreationDate="2023-10-11T10:02:36.683" Score="2" ViewCount="109" Body="&lt;p&gt;Having a look at the attached image (original at &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:CourtHotspots.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia Hot Spot page&lt;/a&gt;) I noticed that all mantle plumes originating from lower mantle (in red) are under oceans. Why?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DdGyP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DdGyP.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18490" LastActivityDate="2023-10-20T02:00:59.717" Title="Why are all lower mantle plumes under oceans?" Tags="|geology|volcanology|mantle-plumes|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25641" PostTypeId="1" AcceptedAnswerId="25644" CreationDate="2023-10-11T13:29:04.200" Score="3" ViewCount="211" Body="&lt;p&gt;I was exploring Kazakhstan in Google Maps satellite mode and these yellow areas caught my eyes:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ESW3t.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ESW3t.jpg&quot; alt=&quot;Yellow&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;There are numerous lookalike lands when you zoom back.&lt;/p&gt;&#xA;&lt;p&gt;First I thought these are small deserts because of their yellow color. But when I zoomed in I found they are very white; so the new thought was that these are snow and ice glaciers. But this one I published its image has a 22 miles length and most of them have trees in them. Can it still be a glacier?&lt;/p&gt;&#xA;&lt;p&gt;Also, a minor question: What are the small circles just to the right? They seem to be man-made and industrical.&lt;/p&gt;&#xA;" OwnerUserId="29082" LastEditorUserId="6298" LastEditDate="2023-10-12T10:23:29.080" LastActivityDate="2023-11-06T00:27:03.540" Title="What are these large yellow areas in Kazakhstan?" Tags="|satellite-oddities|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25642" PostTypeId="1" AcceptedAnswerId="25645" CreationDate="2023-10-11T17:42:58.977" Score="1" ViewCount="76" Body="&lt;p&gt;We have a set of old sections with drill data that I would like to extract and model. I can add sections just fine in Leapfrog, but I have issues with the drill holes, especially connecting the drill holes from the sections with the planar/top view of the section which is found directly under the section. How can I connect the drill hole with the planar view so I can get the dip and azimuth calculated automatically?&lt;/p&gt;&#xA;&lt;p&gt;The software we use includes QGIS, ArcGIS Pro, Global Mapper, and Leapfrog, but for this, we are ready to learn something new if needed.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JYBv2.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JYBv2.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27064" LastActivityDate="2023-10-12T10:25:48.297" Title="How to connect drillhole from section to the planar view to calculate dip and azimuth?" Tags="|geology|geophysics|drilling|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25644" PostTypeId="2" ParentId="25641" CreationDate="2023-10-12T00:50:34.633" Score="5" Body="&lt;p&gt;Those are sand dunes and other sand deposits associated with rivers.  If you use the Google Map &amp;quot;Explore&amp;quot; (aka Show Imagery) option, there are many photos showing the close-ups of those types of areas.  See &lt;a href=&quot;https://www.google.com/maps/@48.2268607,55.7716132,3a,75y,90t/data=!3m8!1e2!3m6!1sAF1QipPrqTiOfLfUBdM1L4TKTz01LQwrR2icfmErrzVF!2e10!3e12!6shttps:%2F%2Flh5.googleusercontent.com%2Fp%2FAF1QipPrqTiOfLfUBdM1L4TKTz01LQwrR2icfmErrzVF%3Dw203-h270-k-no!7i3024!8i4032!5m1!1e4?entry=ttu&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;https://www.google.com/maps/@49.0407305,54.7644564,3a,75y,90t/data=!3m8!1e2!3m6!1sAF1QipPLszEEIUDSiH6xS110VtfC-oTc9bdzxrdi1foK!2e10!3e12!6shttps:%2F%2Flh5.googleusercontent.com%2Fp%2FAF1QipPLszEEIUDSiH6xS110VtfC-oTc9bdzxrdi1foK%3Dw203-h203-k-no!7i1080!8i1080!5m1!1e4?entry=ttu&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;https://www.google.com/maps/@48.2268607,55.7716132,3a,75y,90t/data=!3m8!1e2!3m6!1sAF1QipNQDszbl7RZJdfs5dXFDrUQ_cBez8agk9U0hsqv!2e10!3e12!6shttps:%2F%2Flh5.googleusercontent.com%2Fp%2FAF1QipNQDszbl7RZJdfs5dXFDrUQ_cBez8agk9U0hsqv%3Dw203-h270-k-no!7i3024!8i4032!5m1!1e4?entry=ttu&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;https://www.google.com/maps/@48.2268607,55.7716132,3a,75y,90t/data=!3m8!1e2!3m6!1sAF1QipNoXF3uhoFcmudklFyHS5YZTBUCDYAn8l1yshsn!2e10!3e12!6shttps:%2F%2Flh5.googleusercontent.com%2Fp%2FAF1QipNoXF3uhoFcmudklFyHS5YZTBUCDYAn8l1yshsn%3Dw203-h270-k-no!7i3024!8i4032!5m1!1e4?entry=ttu&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; for examples.  The circles are part of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Zhanazhol_Field&quot; rel=&quot;noreferrer&quot;&gt;Zhanazhol Oil field&lt;/a&gt; (e.g. drilling).&lt;/p&gt;&#xA;&lt;p&gt;You can see a blurb about those types of sand dunes in the &lt;a href=&quot;https://earthobservatory.nasa.gov/images/150271/oyyl-dune-field-kazakhstan&quot; rel=&quot;noreferrer&quot;&gt;NASA Earth Observatory article on the Oyyl Dune Field&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Dune fields grow in regions where there is a significant supply of sand and sufficient wind speeds to transport the grains. Fluvial floodplains are one common source of sand, so dune fields often form immediately downwind of them. Floodplains and dune fields often occupy regions known as “sinks”—topographic low areas where sediment is deposited. The sink shown here sits approximately 90 meters (300 feet) below the elevation of the surrounding steppe.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fNdw7.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fNdw7.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2023-10-12T00:57:51.143" LastActivityDate="2023-10-12T00:57:51.143" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25645" PostTypeId="2" ParentId="25642" CreationDate="2023-10-12T10:25:48.297" Score="2" Body="&lt;p&gt;Digitizing paper based information, and more specifically the voids of underground mines, was not unusual from the mid 1980s until the mid to late 1990s. Then, large format &lt;a href=&quot;https://www.gtcocalcomp.com/large-format-digitizers/&quot; rel=&quot;nofollow noreferrer&quot;&gt;digitizers&lt;/a&gt; were readily available.&lt;/p&gt;&#xA;&lt;p&gt;Digitizing paper based drill hole information might have been done, but I'm not aware of anyone who did it the way you are trying to do it. If it needed to be done people tried to obtain the written geological logs of the holes and manually enter that data, with the collar survey data and the down hole survey data, if it existed, into a newly created digital database. It was tedious and what you will need to do will be equally tedious.&lt;/p&gt;&#xA;&lt;p&gt;I'm unaware of any software that can do what you need. That doesn't mean it doesn't exist, I'm just unaware of it because I've never needed to do it.&lt;/p&gt;&#xA;&lt;p&gt;What you need to do is direct mapping between the sectional data and the data in plan. I'm assuming the section data is on specific northings. Unless the northing has been written next to the collar of the hole in the plan view you will have to take the northing from the section northing and assign it to the collar of the drill hole. Sections typically have an easting and elevation grid. From this you will be able to get the easting and elevation of points down each hole. This will give you the three points you need to define the trace of the drill holes in three dimensions. I am also assuming the scale for northings is the same as the scale for eastings (or westings).&lt;/p&gt;&#xA;&lt;p&gt;From the picture in the question, the lateral length of the holes is not long compare to the down hole length.&lt;/p&gt;&#xA;&lt;p&gt;Initially for each hole, on the plan view, you will need to draw a faint horizontal line from the collar to the left. This will represent your section line.&lt;/p&gt;&#xA;&lt;p&gt;For each drill hole, you will need to mark the collar and toe in the plan diagram. You then draw a faint vertical line from each point on the plan diagram until it intersects the drill hole in the vertical (cross) section. The intersection point at the drill hole trace in sectional view will give you the easting and elevation of the point. To obtain the northing from the point you need to add or subtract the distance the drill hole trace, in plan, is from the northing line that was drawn for the hole. If the drill hole trace is to the north of the line the difference is added to the section northing. If it is south of the line it is subtracted.&lt;/p&gt;&#xA;&lt;p&gt;You will then have to do likewise for points in between the collar and the toe. To reduce the workload don't bother about taking points along straight portions of each hole. Mark the start and end of curved parts of the hole in plan view and get the data for those points. Then do the same for points along the curved parts. If you want reasonable accuracy have the points spaced at one meter intervals.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-10-12T10:25:48.297" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25646" PostTypeId="1" AcceptedAnswerId="25648" CreationDate="2023-10-12T13:21:19.533" Score="11" ViewCount="2502" Body="&lt;p&gt;I was looking at the Kura river in Google Maps satellite mode and I saw these U-shaped bodies of water:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/cOrf3.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/cOrf3.jpg&quot; alt=&quot;U-Shaped&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;There are other U-shaped bodies of water too:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://maps.app.goo.gl/ZNRfYApRkHVEnDpW6&quot; rel=&quot;noreferrer&quot;&gt;40.615881° N, 47.205031° E&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://goo.gl/maps/T5KKuHs2uZRDB7Fj8&quot; rel=&quot;noreferrer&quot;&gt;40.101139° N, 47.963825° E&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;And so many others.&lt;/p&gt;&#xA;&lt;p&gt;Why are these U-shaped bodies of water frequent in the region?&lt;/p&gt;&#xA;" OwnerUserId="29082" LastActivityDate="2023-10-12T14:39:53.993" Title="Why are these U-shaped bodies of water frequent near Kura river?" Tags="|water|rivers|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25647" PostTypeId="2" ParentId="24156" CreationDate="2023-10-12T13:46:14.047" Score="0" Body="&lt;p&gt;You can refer to &lt;a href=&quot;https://earthscience.stackexchange.com/questions/16570/how-to-calculate-relative-humidity-from-temperature-dew-point-and-pressure?newreg=86cf2a3bb5bb47c5afd5fcaccfea796a&quot;&gt;this question&lt;/a&gt; for more detail. I calculated RH by using ERA5-land t2m and d2m. I think the result was ok.&lt;/p&gt;&#xA;" OwnerUserId="29801" LastActivityDate="2023-10-12T13:46:14.047" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25648" PostTypeId="2" ParentId="25646" CreationDate="2023-10-12T14:39:53.993" Score="26" Body="&lt;p&gt;They look like &lt;a href=&quot;https://en.wikipedia.org/wiki/Oxbow_lake&quot; rel=&quot;noreferrer&quot;&gt;oxbow lakes&lt;/a&gt;. Some meander scars (crescent-shaped, but dry) are also visible. Here is an excerpt of the &amp;quot;OXBOW&amp;quot; entry in &lt;em&gt;&lt;a href=&quot;https://www.routledge.com/Encyclopedia-of-Geomorphology/Goudie/p/book/9780415863001&quot; rel=&quot;noreferrer&quot;&gt;Encyclopedia of Geomorphology&lt;/a&gt;&lt;/em&gt; (2013):&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;An abandoned meander (see MEANDERING) loop along an alluvial river. It&#xA;is the most common type of lake of fluvial origin. As a logical&#xA;consequence of the lateral shifting and the general downstream&#xA;migration of meanders, it develops from the interplay of channel&#xA;erosion and accumulation separated in space. Oxbows are produced by&#xA;meander cutoffs [...] The American name emphasizes the crescent shape,&#xA;while in many other languages an oxbow is called a ‘dead arm’ (e.g. in&#xA;French: &lt;em&gt;bras mort&lt;/em&gt;). [...] Meander scars are oxbows completely filled&#xA;up with mineral and organic matter. They remain discernible in the&#xA;landscape for a long time. Classic examples are found along several&#xA;major rivers of the world, including the Mississippi, the Amazon and&#xA;the large rivers of Siberia.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2023-10-12T14:39:53.993" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="25650" PostTypeId="2" ParentId="25620" CreationDate="2023-10-13T09:57:56.697" Score="2" Body="&lt;p&gt;The &lt;code&gt;miptable&lt;/code&gt; &lt;code&gt;Emon&lt;/code&gt; is the extended variable list, which is basically there to stop the large number of more niche, rarely-used variables from cluttering the core monthly tables like &lt;code&gt;Amon&lt;/code&gt;, &lt;code&gt;Omon&lt;/code&gt;, &lt;code&gt;Lmon&lt;/code&gt;, etc.  See the comment in the &lt;a href=&quot;https://clipc-services.ceda.ac.uk/dreq/u/MIPtable::Emon.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Data Request Record&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Data in the 'E...' tables is requested by specific endorsed MIPs, and is generally more specialised than other tables.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The variables in &lt;code&gt;Emon&lt;/code&gt; tend to have priorities 2 and 3, whereas those in the core monthly lists tend to have priority 1.&lt;/p&gt;&#xA;&lt;p&gt;I can't see any difference in the definitions of &lt;code&gt;Amon.ta&lt;/code&gt; and &lt;code&gt;Emon.ta&lt;/code&gt; other than the pressure levels, e.g., they are both monthly time means.  As always, check the metadata for the files you're using in case a modelling center has done something different from the Data Request.&lt;/p&gt;&#xA;" OwnerUserId="106" LastActivityDate="2023-10-13T09:57:56.697" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25651" PostTypeId="2" ParentId="25640" CreationDate="2023-10-13T14:13:18.770" Score="3" Body="&lt;p&gt;Mantle plumes are part of the movement driving plate tectonics.  These movements push continental plates apart making oceans.  It's not that they occur in oceans, they cause oceans.  As pointed out in a comment, the Afar spot in Africa is not under an ocean, but it is causing the rift valley in Africa, which is full of lakes, which given geological time will connect and result in the continental plates separating and the remaining space filling with water.&lt;/p&gt;&#xA;" OwnerUserId="12945" LastActivityDate="2023-10-13T14:13:18.770" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25652" PostTypeId="1" CreationDate="2023-10-13T14:18:46.857" Score="2" ViewCount="78" Body="&lt;p&gt;I always considered geothermal energy a vast, emission-free green energy source. That is, if you happen to live in the right place. That also seems to be the sentiment online.&lt;/p&gt;&#xA;&lt;p&gt;I live in Italy, in the &amp;quot;right place&amp;quot; — a seismically active area. A few “binary” geothermal plants are located nearby, with many more planned over the coming years, mainly due to the EU energy crisis. Here, many people vehemently oppose these projects. So, I did some research, and what I found surprised me. I would like to tap the wisdom of the crowd to understand if I got anything wrong and gain additional perspectives.&lt;/p&gt;&#xA;&lt;p&gt;I found that geothermal refers to two different technologies.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;The first uses geothermal heat for heating houses. Water is injected into the ground in a closed loop, heated, and used as a heat source. The underground temperature needed for this system is not high. This seems to be a clean and sustainable system. The only problem is that it is only possible to transport the hot water a short distance before the water in the pipes cools down. It is, therefore, limited in its utility and economic value.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;The second uses geothermal heat to drive a turbine. Electricity is then transported via the grid. The problem is that a much higher water temperature is required to turn water into steam. Also, much energy is lost in the conversion process from heat to electricity. To overcome these difficulties, fracking is used. Not just one time but periodically since the underground water temperature drops over time.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;This is problematic for several reasons:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;Fracking has been shown to trigger earthquakes [1], and since geothermal is viable mainly in areas that are already seismically active, such as where I live, it seems to be a bad match.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Since geothermal activity has started in the area, the level of arsenic, other toxic minerals, and heavy metals in the groundwater has risen. In some places, arsenic is now at twice the level recommended by the WHO and over the legal limit [2].&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Since geothermal activity has started in the area, the water level in the aquifer has dropped by 200 to 300 meters. In addition, the flow rate of many rivers has decreased significantly or even ceased completely. This seems to be related to the fracking activity, and since this area provides water to several cities in central Italy, it seems to be a big problem [3].&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Even more surprisingly, according to my calculations, Solar seems to be a more economical option. The last plant built here has a 40 MW capacity, and the construction cost around 130 million euros [4]. An equivalent solar installation only costs 30 million euros [5]. In addition, the running costs for solar plants seem to be lower than those of geothermal ones. Solar does require more land, about 100 hectares for a 40 MW plant, but land is abundant around here.&lt;/p&gt;&#xA;&lt;p&gt;Another important fact is that the Government of Italian incentivizes energy companies since geothermal electricity is considered green. For each MWh produced, a plant receives an incentive of 99 euros. Considering that it produces 300 gigawatt-hours annually, the incentive is 29.7 million euros. Incentives are given for a 25-year period, so overall, 742.5 million euros [6].&lt;/p&gt;&#xA;&lt;p&gt;Am I getting anything fundamentally wrong in my reasoning? If not, should we consider geothermal electricity green? Any advice is appreciated.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;[1] &lt;a href=&quot;https://doi.org/10.1126/science.aag2583&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1126/science.aag2583&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;[2] &lt;a href=&quot;https://www.ars.toscana.it/2-articoli/4707-geotermia-e-salute-in-toscana-presentato-il-rapporto-2021-di-ars.html#&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ars.toscana.it/2-articoli/4707-geotermia-e-salute-in-toscana-presentato-il-rapporto-2021-di-ars.html#&lt;/a&gt; (Italian)&lt;/p&gt;&#xA;&lt;p&gt;[3] &lt;a href=&quot;https://www.intechopen.com/chapters/79332&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.intechopen.com/chapters/79332&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;[4] &lt;a href=&quot;https://www.ilgiunco.net/2016/07/25/bagnore-4-ecco-la-centrale-costata-130-milioni-produrra-310-milioni-di-kilowattora-allanno/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ilgiunco.net/2016/07/25/bagnore-4-ecco-la-centrale-costata-130-milioni-produrra-310-milioni-di-kilowattora-allanno/&lt;/a&gt; (Italian)&lt;/p&gt;&#xA;&lt;p&gt;[5] &lt;a href=&quot;https://www.pfnexus.com/blog/starting-a-solar-farm&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.pfnexus.com/blog/starting-a-solar-farm&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;[6] &lt;a href=&quot;https://www.internazionale.it/reportage/stefano-liberti/2020/07/24/italia-energia-alto-rischio&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.internazionale.it/reportage/stefano-liberti/2020/07/24/italia-energia-alto-rischio&lt;/a&gt; (Italian)&lt;/p&gt;&#xA;" OwnerUserId="29811" LastEditorUserId="6129" LastEditDate="2023-10-16T17:18:55.500" LastActivityDate="2023-10-16T17:18:55.500" Title="Should geothermal electricity be considered green?" Tags="|geothermal-heat|fracking|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25653" PostTypeId="1" CreationDate="2023-10-13T19:22:14.643" Score="3" ViewCount="70" Body="&lt;p&gt;I'm examining several pollutant variables -- like CO2, lead, NOX etc -- and wondering how I can weight them appropriately to have some kind of comparability. Not all pollutants are equally bad for the environment and some have only local rather than global impacts.&lt;/p&gt;&#xA;&lt;p&gt;Could one transfer a ton of pollutant X and pollutant Y into a common comparison of say implied mortality costs, CO2 footprint equivalents?&lt;/p&gt;&#xA;&lt;p&gt;is there a literature on this, or some widely used methods?&lt;/p&gt;&#xA;" OwnerUserId="29812" LastEditorUserId="543" LastEditDate="2023-10-15T00:34:05.413" LastActivityDate="2024-03-15T06:02:45.300" Title="How to combine different air pollutants into a common measure?" Tags="|measurements|air-pollution|greenhouse-gases|pollution|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25654" PostTypeId="2" ParentId="18284" CreationDate="2023-10-14T08:28:54.147" Score="0" Body="&lt;p&gt;So, you are asking what our Magnetosphere would be like if the Earth's core was composed of something different than our current composition, and if it was copper, what effects would that have on it and the gravitational forces as well.&#xA;To answer there are 3 things that are most likely the most prevalent qualities of the Magnetosphere and core of Earth.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Consider that our current composition of inner and outer core is what allows our magnetosphere to be the most powerful electromagnetic field of any rocky celestial body in the known universe.&lt;/li&gt;&#xA;&lt;li&gt;the magnetosphere acts as a shield, protecting our planet&#xA;from harmful solar radiation and charged particles&lt;/li&gt;&#xA;&lt;li&gt;it is generated by the movement of molten iron in the Earth's outer core, which creates a dynamo effect that generates the magnetic field.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;-To logic out the most possible answer based on these considerations:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;If the Earth's core was composed of a different material, such as copper, it is likely that the magnetic field would be weaker or non-existent.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Copper is not a magnetic material, so it cannot generate a magnetic field. Therefore, if our core was made of copper, it is likely that our planet would not have a magnetosphere at all, or it would be much weaker than it currently is.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;-About Gravity-&lt;/p&gt;&#xA;&lt;p&gt;The gravitational forces on Earth would also be affected by a change in core composition because the strength of gravity is determined by the mass of an object, so if the Earth's core was made of a lighter or heavier material than iron, it would affect the planet's overall mass and therefore its gravitational force. However, it is difficult to predict exactly how this would affect the planet's gravity without more specific information about the new core composition.&lt;/p&gt;&#xA;&lt;p&gt;In summary, the current composition of Earth's core is crucial for generating our magnetosphere and protecting life on our planet. If the core was composed of a different material, such as copper, it is likely that our magnetosphere would be weaker or non-existent, and this would have significant implications for life on Earth. Since the planets of our solar system formed around the same time, and considering the current condition of Mars and Mercury, one can assume atmospheric death by this point in our timeline. We literally have the perfect conditions for life to exist and life only exists due to the ELectromagnetic Fields of this planet. It is akin to God in all honesty, for without them, life would have to develop its own or be wiped off the face of earth.&lt;/p&gt;&#xA;" OwnerUserId="29816" LastActivityDate="2023-10-14T08:28:54.147" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25655" PostTypeId="1" AcceptedAnswerId="25660" CreationDate="2023-10-14T12:10:50.877" Score="3" ViewCount="71" Body="&lt;p&gt;If I have wind speeds at 80m and 120m above the surface and I am interested in approximating the speed at 100m, is it valid to just average the 80 and 120 speeds? In other words, should I expect wind speed to be a linear function of height or would a nonlinear function be more appropriate?&lt;/p&gt;&#xA;" OwnerUserId="29818" LastActivityDate="2023-10-15T12:23:09.797" Title="Interpolating Wind Speed" Tags="|wind|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25656" PostTypeId="1" CreationDate="2023-10-14T15:03:42.957" Score="-2" ViewCount="50" Body="&lt;p&gt;I know how crazy this will sound so let me ease into the craziness.&lt;/p&gt;&#xA;&lt;p&gt;I recently read a paper on the Chicxulub crater and one line caught my attention detailing a hydrothermal vent system that resulted from the impact and “lived”&#xA;for tens of thousands of years-.  I then thought about the uniformity of impact craters both in structures and material compositions.l looked at some complex impact craters on mars and some had  internal structures which looked like they were arranged similar to a spectrophotometer used to split light into wavelengths and then thought generally how impact craters look like eyes and wondered if it was all more than metaphorical.&lt;/p&gt;&#xA;&lt;p&gt;Here’s my thought process: at a basic level an eye would need a material to convert light into an electrical signal (photoelectric), a material to carry the signal (conductive) and then something to process the signal (some type of processor/brain).&lt;/p&gt;&#xA;&lt;p&gt;Impact craters are usually rich in magnetite (photoelectric), have shock quartz veins (conductive- while the mechanism is a little complex) and this is the weakest part of the evidence but quartz can be also used to store and process info and shocked quartz has organized structure (I forget the name) that kinda seem like they could be binary.&lt;/p&gt;&#xA;&lt;p&gt;Is there any other evidence that impact craters may be part of some type of sensor/life? Maybe one that uses geothermal heat as its energy source. I realize it’s far fetched but some of the crazy complexity and organization of Martian impact craters I’ve seen makes me curious if there isn’t more intent in their formation- maybe coded in electromagnetism or something.&lt;/p&gt;&#xA;&lt;p&gt;And I’m not suggesting our understanding of the mechanisms behind impact crater formation is wrong, just incomplete and that there may be additional mechanism directing their formation.&lt;/p&gt;&#xA;" OwnerUserId="29821" LastEditorUserId="29821" LastEditDate="2023-10-14T16:29:33.500" LastActivityDate="2023-10-16T07:47:38.297" Title="Ocular similarities in Impact crater" Tags="|meteorite|astrobiology|impact-craters|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25657" PostTypeId="2" ParentId="25653" CreationDate="2023-10-14T17:53:03.307" Score="0" Body="&lt;p&gt;It’s not exactly what you’re asking for but  quality index is the closest that comes to mind.&#xA;&lt;a href=&quot;https://www.airnow.gov/aqi/aqi-basics/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.airnow.gov/aqi/aqi-basics/&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;There are so many variables,  it is difficult to develop one accurate unit of measure. For instance, high pollen count or high concentrations of an allergen could be deadly for some people and harmless to others. Different combinations and/or  attributes of pollutants might be deadly where as a small change to them might make them harmless.&lt;/p&gt;&#xA;&lt;p&gt;if the particulates in your particle size count were silica dust causing lung abrasions it could amplify the effects of something like formaldehyde. But the harm caused by the same concentration of formaldehyde and the same particle size count would be totally different if those particles were just dust from soil.&lt;/p&gt;&#xA;" OwnerUserId="29821" LastActivityDate="2023-10-14T17:53:03.307" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25658" PostTypeId="2" ParentId="25653" CreationDate="2023-10-15T00:12:36.410" Score="0" Body="&lt;p&gt;Climate pollutants and air-quality pollutants would not be part of the same index, except perhaps total &amp;quot;economic costs&amp;quot;.  Climate pollutants can be lumped into a &lt;a href=&quot;https://www.epa.gov/energy/greenhouse-gas-equivalencies-calculator&quot; rel=&quot;nofollow noreferrer&quot;&gt;CO2-equivalent value&lt;/a&gt;, which relies on the residence time and warming potential.&lt;/p&gt;&#xA;&lt;p&gt;For criteria air pollutants that are regularly monitored (NO2, CO, O3, PM2.5, SO2), EPA uses a method which reports the air quality index for the worst pollutant.  For toxic air pollutants, air quality agencies have typically done the same thing, just pick the worst one.&lt;/p&gt;&#xA;&lt;p&gt;Health based standards are usually expressed in terms of the cancer or mortality probability for a single pollutant. However, cumulative and combined exposure to multiple air pollutants can have more negative health effects than just &amp;quot;the worst one&amp;quot;, or even worse than the simple additive effects across all pollutants.  It is very difficult to come up with a cumulative and combined health metric because most health studies don't have that type of robust information.  But, we do know that the health effects are compounded when their are multiple stressors. In order to calculate the cumulative health impacts of multiple air pollutants, some people use &lt;a href=&quot;https://www.epa.gov/benmap/benmap-ce-manual-and-appendices&quot; rel=&quot;nofollow noreferrer&quot;&gt;BenMAP&lt;/a&gt;, which I believe incorporates the &lt;a href=&quot;http://www.sthda.com/english/wiki/cox-proportional-hazards-model#:%7E:text=The%20Cox%20proportional%2Dhazards%20model,one%20or%20more%20predictor%20variables.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cox proportional hazards model&lt;/a&gt; to make the calculation.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Cox proportional-hazards model (Cox, 1972) is essentially a [statistical] regression model commonly used in medical research for investigating the association between the survival time of patients and one or more predictor variables.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;You might find other useful models at the EPA's &lt;a href=&quot;https://www.epa.gov/fera&quot; rel=&quot;nofollow noreferrer&quot;&gt;Air: Fate, Exposure and Risk Analysis&lt;/a&gt; site.&lt;/p&gt;&#xA;&lt;p&gt;Environmental groups are pushing air quality agencies to now consider cumulative exposure when permitting facilities, especially under the environmental justice context.  See &lt;a href=&quot;https://www.oregon.gov/deq/aq/air-toxics/pages/chrp.aspx&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oregon's Cumulative Health Risk pilot study for toxics&lt;/a&gt;, as an example.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2023-10-17T05:13:21.040" LastActivityDate="2023-10-17T05:13:21.040" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25659" PostTypeId="1" CreationDate="2023-10-15T10:22:10.277" Score="1" ViewCount="32" Body="&lt;p&gt;It should be far enough away from land so that another country may not stake claim on the island, but in a shallow enough area such that dredging and depositing sand and other building materials is relatively easy.&lt;/p&gt;&#xA;" OwnerUserId="29825" LastActivityDate="2023-10-15T10:22:10.277" Title="I want to build a new island country in the ocean. Where is the best place to build it?" Tags="|oceanography|islands|" AnswerCount="0" CommentCount="1" ClosedDate="2023-10-17T04:56:14.483" ContentLicense="CC BY-SA 4.0" />
  <row Id="25660" PostTypeId="2" ParentId="25655" CreationDate="2023-10-15T12:23:09.797" Score="1" Body="&lt;p&gt;The content below is based on expressions found in &lt;a href=&quot;https://en.wikipedia.org/wiki/Wind_gradient&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wind gradient&lt;/a&gt; from Wikipedia.  See that link for more background information.&lt;/p&gt;&#xA;&lt;p&gt;Wind speed as a function of height can be modeled with the following expression:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$v_2 = v_1 \left(\frac{h_2}{h_1}\right)^a$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where &lt;span class=&quot;math-container&quot;&gt;$v_1$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$v_2$&lt;/span&gt; are the wind speeds are heights &lt;span class=&quot;math-container&quot;&gt;$h_1$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$h_2$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$a$&lt;/span&gt; is a parameter related to the atmospheric stability.&lt;/p&gt;&#xA;&lt;p&gt;Given your two values for wind speed at different height we want to solve for &lt;span class=&quot;math-container&quot;&gt;$a$&lt;/span&gt;:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$a = \frac{\ln(v_2/v_1)}{\ln(h_2/h_1)}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;You can now use this value, along with the original height / wind speed pairs to evaluate the wind speed at a different height.&lt;/p&gt;&#xA;&lt;p&gt;The model will likely be best when the evaluated hight is between the points used to compute &lt;span class=&quot;math-container&quot;&gt;$a$&lt;/span&gt;, basically interpolation will be better than extrapolation.&lt;/p&gt;&#xA;" OwnerUserId="18088" LastActivityDate="2023-10-15T12:23:09.797" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25661" PostTypeId="1" CreationDate="2023-10-15T21:35:47.060" Score="0" ViewCount="138" Body="&lt;p&gt;I recently measured groundwater levels using a tape in three different boreholes for where the holes are in same area. Each hole had a different level of water. Holes A and B are just 4 meters apart and hole C is about 70 m from holes A and B.&lt;/p&gt;&#xA;&lt;p&gt;The water depth in A was 12 ft (3.7 m), in B it was 9 ft (3 m) and in C it was about 71 ft (22 m). How can the water depth be different for holes so close to one another in the same area?&lt;/p&gt;&#xA;&lt;p&gt;I asked professor about this and he replied, it is due to different heights of each borehole and asked me to Google it. I assumed that since water in equilibrium has the same water level, so the water in each borehole will be at same depth. But the readings doesn't match with my assumption ? What could be the reason?&lt;/p&gt;&#xA;" OwnerUserId="29691" LastEditorUserId="21672" LastEditDate="2023-10-20T09:38:01.660" LastActivityDate="2023-10-20T09:38:01.660" Title="Why the groundwater depth is different in same area" Tags="|geology|groundwater|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="25662" PostTypeId="2" ParentId="18284" CreationDate="2023-10-15T22:04:59.400" Score="2" Body="&lt;p&gt;As explained in some comments, it is the dynamo effect from the flow of liquid metal that creates the magnetic field, not the magnetic properties the solid metal might reveal under surface conditions. In fact, the liquid does not even need to be a metal; it can be any electrical conductor such as water containing dissolved salts. On smaller objects that cannot support a metallic core, a (weak) magnetic field could be generated by a subterranean water-based solution, &lt;a href=&quot;https://science.nasa.gov/jupiter/moons/ganymede/facts/&quot; rel=&quot;nofollow noreferrer&quot;&gt;as on Jupiter's moon Ganymede&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Computer models show Ganymede might have ice and oceans stacked up in several layers like a club sandwich. Scientists first suspected Ganymede had an underground ocean in the 1970s. The Galileo spacecraft discovered Ganymede's magnetic field in 1996, providing evidence to support the theory.&lt;/p&gt;&#xA;&lt;p&gt;NASA’s Hubble Space Telescope has found more evidence for an underground saltwater ocean, and evidence of a thin oxygen atmosphere on Ganymede.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Where we have a liquid metal core, one metal is more or less as electrically conductive and as fluid as another, so any molten metal would be capable of generating the necessary dynamo effect.&lt;/p&gt;&#xA;&lt;p&gt;However, there is one subtlety. Under ambient pressure copper melts several hundred degrees Celsius lower than iron or nickel, or any of their alloys (alloying does not markedly depress the melting point with iron and nickel). If such a difference were to persist to Earth-core pressures, a copper-based core might solidify more extensively and leave less fluid for dynamo generation.&lt;/p&gt;&#xA;&lt;p&gt;In the end, however, it is iron and nickel that are the most common metals likely to get into the core, in terms of both element generation and chemistry (copper is usually considered chalcophile, tending to form sulfides in the crust/mantle), so the mostly fluid iron-nickel core with a strong dynamo effect is what we have.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2023-10-20T01:56:28.967" LastActivityDate="2023-10-20T01:56:28.967" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25663" PostTypeId="2" ParentId="25656" CreationDate="2023-10-16T07:47:38.297" Score="1" Body="&lt;p&gt;To begin with, hydrothermal vents lasting for &amp;quot;thousands of years&amp;quot; is a very small period of time in geological time scales.&lt;/p&gt;&#xA;&lt;p&gt;As to your hypothesis concerning shocked quartz &amp;amp; magnetite in impact craters somehow forming an optical sensing &amp;amp; processing system, until someone can provide evidence of such a possibility the answer would be, &lt;strong&gt;exceedingly unlikely&lt;/strong&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-10-16T07:47:38.297" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25664" PostTypeId="2" ParentId="12740" CreationDate="2023-10-16T16:51:58.213" Score="4" Body="&lt;p&gt;The loudest thunder will be heard where the lightning bolt hits, and this could be about 160 dB for the strongest &lt;a href=&quot;https://earthobservatory.nasa.gov/images/148933/superbolts-carry-super-power&quot; rel=&quot;nofollow noreferrer&quot;&gt;superbolts&lt;/a&gt;. Good places to observe and hear such bolts are on the Mediterranean Sea in winter or the Andean Plateau.&lt;/p&gt;&#xA;&lt;p&gt;The loudness next to the channel of &lt;a href=&quot;https://doi.org/10.1002/2015GL064451&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;Dayeh, M. A., et al. (2015), First images of thunder: Acoustic imaging of triggered lightning, Geophys. Res. Lett., 42, 6051–6057, doi:10.1002/2015GL064451.&quot;&gt;triggered lightning strikes&lt;/a&gt; is well correlated with the peak current and measurements indicate that this is as high as 142±3 dB for a peak lightning current of about 20 kA.&#xA;Lightning superbolts have been observed with &lt;a href=&quot;https://actu.epfl.ch/static/upload/files/LightningOnlineDatabase.pdf&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;Extreme Values of Lightning Parameters, A. Smorgonskii, M. Rubinstein, F. Rachidi, Proc. 25th International Lightning Detection Conference &amp;amp; 7th International Lightning Meteorology Conference, March. 2018.&quot;&gt;peak currents of almost 1000 kA&lt;/a&gt;, so we might expect their peak loudness to be 10 log(1000/20) = 17 dB louder, i.e. about 160 dB.  Such superbolts &lt;a href=&quot;https://doi.org/10.1029/2019JD030975&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;Global distribution of superbolts. Holzworth, R. H., McCarthy, M. P., Brundell, J. B., Jacobson, A. R., &amp;amp; Rodger, C. J. (2019). Journal of Geophysical Research: Atmospheres, 124, 9996–10005.&quot;&gt;are most common&lt;/a&gt; over the Northeast Atlantic, the Mediterranean, and the Andean plateau, but also occur elsewhere.&lt;/p&gt;&#xA;" OwnerUserId="27775" LastEditorUserId="27775" LastEditDate="2023-10-17T14:18:41.683" LastActivityDate="2023-10-17T14:18:41.683" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25665" PostTypeId="2" ParentId="25661" CreationDate="2023-10-17T08:57:36.640" Score="2" Body="&lt;p&gt;All things being equal your assumption that boreholes in close proximity to one another would have the same water level is correct. However there are a number of factors that could alter this (assuming you have corrected for any difference in surface elevation and none of the 3 boreholes are pumped).&lt;/p&gt;&#xA;&lt;p&gt;One possibility is that the holes have been drilled, or cased, to different depths, and are therefore connected to different aquifers. For instance A and B could be shallow and completed in a perched aquifer, and C drilled deeper into a regional aquifer. A similar picture would emerge if A and B are drilled deeper into confined semi-artesian aquifers, and C is the shallow borehole. The latter seems likely in the context of a paper that is discussing confined aquifers. Interpretation of measurements in confined aquifers can be complicated as the observed pressure at a particular depth depends not only on the aquifer water content, but also on the mechanical properties of different layers and the water content of overlying layers.&lt;/p&gt;&#xA;&lt;p&gt;Even in a homogeneous aquifer you can expect to see variation in pressure (which will be seen as variation in level) in boreholes that are cased to different depths if there is some vertical flow - so in a recharge area heads may reduce slightly with depth , whereas in a discharge area they would increase with depth.&lt;/p&gt;&#xA;&lt;p&gt;Disparate water levels in boreholes that are close to each other can also often be seen in aquifers where almost all the permeability is from fractures. If the fractures aren't interconnected the water level may vary depending which fracture happens to be intercepted. If there is another well pumping from one of the interconnected fractures, even at considerable distance, you can see wildly different water levels. An extreme version of this can occur when a borehole hasn't actually intercepted any fractures at all, so effectively operates as a cistern and is disconnected from the groundwater system.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2023-10-17T08:57:36.640" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25667" PostTypeId="1" CreationDate="2023-10-17T18:24:16.000" Score="2" ViewCount="37" Body="&lt;p&gt;I understand the additive time series formula is y = trend + Seasonal + cyclic + residual. But what is the value of y. Is it the the combination of trend, seasonal , cyclic and residual which is shown on first row of the graph below and we get value of trend and ger second row graph using trend = y - seasonal - cyclic-residual and so forth?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/STOwG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/STOwG.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29829" LastEditorUserId="29829" LastEditDate="2023-10-17T18:25:16.127" LastActivityDate="2023-10-17T18:25:16.127" Title="what is the value of y in additive time series decomposition" Tags="|geology|geophysics|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25668" PostTypeId="1" CreationDate="2023-10-18T08:02:33.340" Score="1" ViewCount="33" Body="&lt;p&gt;I have been inspecting the World Bank database, including development indicators based on FAO data. For some of these indicators, for instance &amp;quot;&lt;a href=&quot;https://data.worldbank.org/indicator/AG.LND.CROP.ZS?most_recent_value_desc=true&quot; rel=&quot;nofollow noreferrer&quot;&gt;Permanent cropland (% of land area)&lt;/a&gt;&amp;quot; and &amp;quot;&lt;a href=&quot;https://data.worldbank.org/indicator/AG.LND.CREL.HA?most_recent_value_desc=true&quot; rel=&quot;nofollow noreferrer&quot;&gt;Land under cereal production&lt;/a&gt;,&amp;quot; there is an abrupt dislocation in the time series between 1991 and 1992.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/unp77.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/unp77.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is not comparable to the year-to-year variability observed for the remaining years. I assume the dislocations are due to geopolitical events around the time, maybe incorporation of data from the former Soviet Union (the Russian Federation did not formally join the World Bank until 1992) or other states. However I can't tell whether the actual origin is changes in data because new regions or data sources were added or removed to the database, or because of problems on the ground with data reporting, acquisition, logging, sharing, etc, or due to actual changes in land use or production.&lt;/p&gt;&#xA;&lt;p&gt;I checked the World Bank &lt;a href=&quot;https://databank.worldbank.org/reports.aspx?source=2&amp;amp;type=metadata&amp;amp;series=AG.LND.CROP.ZS#&quot; rel=&quot;nofollow noreferrer&quot;&gt;meta data&lt;/a&gt; but found it of little help:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The Food and Agriculture Organization (FAO) tries to impose standard definitions and reporting methods, but complete consistency across countries and over time is not possible. Thus, data on agricultural land in different climates may not be comparable. For example, permanent pastures are quite different in nature and intensity in African countries and dry Middle Eastern countries.&lt;br /&gt;&#xA;True comparability of the data is limited by variations in definitions, statistical methods, and quality of data. Countries use different definitions land use. The Food and Agriculture Organization of the United Nations (FAO), the primary compiler of the data, occasionally adjusts its definitions of land use categories and revises earlier data. Because the data reflect changes in reporting procedures as well as actual changes in land use, apparent trends should be interpreted cautiously.&lt;br /&gt;&#xA;Satellite images show land use that differs from that of ground-based measures in area under cultivation and type of land use. Moreover, land use data in some countries (India is an example) are based on reporting systems designed for collecting tax revenue. With land taxes no longer a major source of government revenue, the quality and coverage of land use data have declined.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Can someone shed light on the exact origin of these dislocations (for instance what sources might have been added or removed to the database, or whether acquisition or processing was done differently, in as much detail as possible)? Based on this I might have some options on modifying the data in such a manner as to minimize the dislocations and make trends clearer (recording of course a note that modifications were made).&lt;/p&gt;&#xA;" OwnerUserId="15191" LastEditorUserId="15191" LastEditDate="2023-10-18T09:12:37.753" LastActivityDate="2023-10-18T09:12:37.753" Title="Origin of dislocations in FAO data between 1991 and 1992 (via World Bank)?" Tags="|open-data|agriculture|data-analysis|database|gis|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25669" PostTypeId="1" AcceptedAnswerId="25671" CreationDate="2023-10-18T08:27:43.070" Score="3" ViewCount="81" Body="&lt;p&gt;I am trying to understand how athmospheric scientists are quantifying effective radiative forcing of different aviation-related warming/cooling effects as a function of total emissions over time.&lt;/p&gt;&#xA;&lt;p&gt;For instance, a recent publication (Penner et al., 2018, &lt;a href=&quot;https://doi.org/10.1029/2018JD029204&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1029/2018JD029204&lt;/a&gt;) mentions, that:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Our best estimate for the forcing of aircraft soot in this model is -0.2 ± 0.06 W/m²;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I read the paper, but could not find &lt;em&gt;over what time period&lt;/em&gt; this level of absolute warming (mW/m²) is supposed to occur.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, the well-known figures by Lee et al. (&lt;a href=&quot;https://doi.org/10.1016/j.atmosenv.2020.117834&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/j.atmosenv.2020.117834&lt;/a&gt;, latest version from 2021) always provide the time horizon. In this example, the effective radiative forcing level from different aviation-related effects are all calculated for the time period 1940-2018.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/DY0ca.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/DY0ca.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Am I missing something in the publication by Penner et al.? Is it convention in atmospheric science to implicitly assume some time period (industrial revolution until the present day?)?&lt;/p&gt;&#xA;" OwnerUserId="29831" LastActivityDate="2023-10-19T14:10:51.727" Title="Effective Radiative Forcing of Aviation Soot: Time Period Considered" Tags="|climate-change|atmosphere|climate-models|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25670" PostTypeId="2" ParentId="24092" CreationDate="2023-10-18T08:34:24.570" Score="1" Body="&lt;p&gt;As a rule of thumb, you can put about 10MW per sq km of wind farm capacity in good areas.&lt;/p&gt;&#xA;&lt;p&gt;The Falklands cover 12,000 km. At 60% capacity factor, they could generate an average of about 70GW with 120GW capacity. Even more given many small islands (with a larger &amp;quot;wind footprint&amp;quot; than their area).&lt;/p&gt;&#xA;&lt;p&gt;Let's say a serious project established a 30GW wind farm averaging 20GW, plus electrolyzer capacity to make hydrogen. The jury is still out on whether hydrogen should be exported as Ammonia.&lt;/p&gt;&#xA;&lt;p&gt;The Falklands doesn't have the industrial capacity for that. It would need to arrive. This would need a new town, similar to some Australian mining towns or Alaskan oil towns, with a few thousand people. This would probably aim to build 300 X 7MW turbines per year. Turbines and towers would be imported, perhaps from Europe or from China, or maybe from a South American wind farm industry (would Argentina export?).&lt;/p&gt;&#xA;&lt;p&gt;This would change the character of the islands, which currently have a population of 2,500 (mostly in Stanley, one of the smallest capital cities). Arguably for the better, though a reclusive sheep farmer may not agree. So whether the Kelpers (the locals) would accept such development - who knows.&lt;/p&gt;&#xA;&lt;p&gt;It could also potentially lower wind speeds in some areas, allowing forestation. Another plus.&lt;/p&gt;&#xA;&lt;p&gt;There are too many variables to know whether such a venture could be profitable, but I think it has potential.&lt;/p&gt;&#xA;" OwnerUserId="29832" LastActivityDate="2023-10-18T08:34:24.570" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25671" PostTypeId="2" ParentId="25669" CreationDate="2023-10-18T14:45:31.020" Score="3" Body="&lt;p&gt;Soot is like water vapour in that its has a very short atmospheric lifetime,  so its forcing is not cumulative that way CO2 is.  There is no need to specify a time period for the contribution from soot.&lt;/p&gt;&#xA;&lt;p&gt;The lifetime of atmospheric CO2 is &lt;a href=&quot;https://doi.org/10.1088/1748-9326/ab3086&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;The contribution of carbon dioxide emissions from the aviation sector to future climate change. E Terrenoire et al 2019 Environ. Res. Lett. 14 084019&quot;&gt;hundreds of years&lt;/a&gt;, so to estimate the current forcing from aviation CO2, you need to know how much CO2 has ever been emitted by aviation. The table in Lee specifies the time period because it includes contributions from CO2 and other long-lived greenhouse gases such as nitrous oxides. (I am not sure why 1940 is the cutoff, but earlier contribution from aviation must be negligible.)&lt;/p&gt;&#xA;&lt;p&gt;The atmospheric lifetime of soot is &lt;a href=&quot;https://en.wikipedia.org/wiki/Black_carbon&quot; rel=&quot;nofollow noreferrer&quot;&gt;days to weeks&lt;/a&gt;, so the current forcing from aviation soot only depends on the current production rate of soot, not the production over a long historical period.  The forcing estimated by Penner is presumably the amount that would disappear in a few weeks if all aviation was grounded.  As the OP notes, it would still have been best if they had specified the base year or level of air traffic.&lt;/p&gt;&#xA;" OwnerUserId="27775" LastEditorUserId="27775" LastEditDate="2023-10-19T14:10:51.727" LastActivityDate="2023-10-19T14:10:51.727" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25672" PostTypeId="1" CreationDate="2023-10-19T09:33:07.337" Score="4" ViewCount="48" Body="&lt;p&gt;I'm trying to find a way to automatically detect the start/end of the 4 seasons based on a time series of daily mean temperature.&lt;/p&gt;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2020GL091753&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; paper summer and winter can be defined as (smoothed) mean temperature being higher or lower than the 75th and 25th percentiles, respectively. These are obviously arbitrary threhsolds, but they seem to work pretty well in many papers I've seen.&#xA;However when I'm trying to reproduce the results I have two main issues:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;the 3rd order polynomial fit is not continous at the boundaries, so I used a more precise spectral filter&lt;/li&gt;&#xA;&lt;li&gt;sometimes the smoothed temperature does not pass the thresholds, making it hard to identify the season&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;This figure shows an example of one of these years&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/IrdTP.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/IrdTP.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As a result some winter season are too short&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6BJY3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6BJY3.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Is there a better way to retrieve seasons from this time series? I'm looking for something simple but little bit more complex than this method solely based on percentile thresholds. I was thinking about K-means clustering maybe...&lt;/p&gt;&#xA;" OwnerUserId="27107" LastActivityDate="2023-10-19T09:33:07.337" Title="Better method to identify seasons in temperature time series?" Tags="|meteorology|temperature|seasons|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25674" PostTypeId="1" CreationDate="2023-10-20T07:14:46.290" Score="1" ViewCount="100" Body="&lt;p&gt;The question, &lt;a href=&quot;https://earthscience.stackexchange.com/questions/25640/why-are-all-lower-mantle-plumes-under-oceans&quot;&gt;Why are all lower mantle plumes under oceans?&lt;/a&gt; has the following diagram&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qMPLA.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qMPLA.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;which was taken from &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:CourtHotspots.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia Commons&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;About half of the large red dots occur on or near the boundaries of tectonic plates. Two others occur within the Pacific Plate: Hawaii and Caroline. Additionally, there are four yellow hot spots in the Pacific: Macdonald, Tahiti, Pitcairn and Marquesas.&lt;/p&gt;&#xA;&lt;p&gt;Based on this, is the Pacific Plate one large continuous plate or is it composed of a number of smaller plates?&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="543" LastEditDate="2023-10-30T16:30:34.337" LastActivityDate="2023-10-30T16:30:34.337" Title="Is the Pacific Plate composed of smaller plates?" Tags="|geology|plate-tectonics|volcanology|tectonics|mantle-plumes|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25675" PostTypeId="1" CreationDate="2023-10-20T18:25:54.717" Score="2" ViewCount="40" Body="&lt;p&gt;I am working on a disaster response logistics case study in which I am using Mi-17 helicopters for transportation of relief to the affected areas in main Chitral city.&lt;/p&gt;&#xA;&lt;p&gt;In this regard, I want to determine the maximum earthquake intensity which can be realized in Chitral City in northern Pakistan?&lt;/p&gt;&#xA;&lt;p&gt;I have searched various databases and on various platforms such as Google Scholar, Science Direct, Scopus etc., but cannot find any information regarding this..&lt;/p&gt;&#xA;" OwnerUserId="29850" LastEditorUserId="29850" LastEditDate="2023-10-21T10:32:38.823" LastActivityDate="2023-10-21T10:32:38.823" Title="What is the maximum intensity with which an earthquake can struck Chitral city in Northern Pakistan?" Tags="|plate-tectonics|earthquakes|natural-disasters|transform-fault|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25676" PostTypeId="1" CreationDate="2023-10-21T02:22:02.630" Score="2" ViewCount="58" Body="&lt;p&gt;I was redirected here from the mathematics StackExchange&lt;/p&gt;&#xA;&lt;p&gt;I am trying to wrap my head around Stommel's Two-Box Model of ocean circulation (specifically of the North Atlantic).&lt;/p&gt;&#xA;&lt;p&gt;The general idea of this model is as follows: &lt;a href=&quot;https://i.stack.imgur.com/wn4Gk.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;Diagram of Stommel's Two-Box Model&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$T_1$&lt;/span&gt; is the temperature of box 1 and &lt;span class=&quot;math-container&quot;&gt;$T_2$&lt;/span&gt; is the temperature of box 2. Also, &lt;span class=&quot;math-container&quot;&gt;$S_1$&lt;/span&gt; is the salinity of box 1, and &lt;span class=&quot;math-container&quot;&gt;$S_2$&lt;/span&gt; is the salinity of box 2. In a &amp;quot;normal&amp;quot; state, we have &lt;span class=&quot;math-container&quot;&gt;$T_2 &amp;gt; T_1$&lt;/span&gt; since box 2 represents water near the equatorial regions. The &lt;span class=&quot;math-container&quot;&gt;$T_1^*, T_2^*, S_1^*$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$S_2^*$&lt;/span&gt; represent the temperature and salinity of the surrounding basins (see posted image above).&lt;/p&gt;&#xA;&lt;p&gt;We also set &lt;span class=&quot;math-container&quot;&gt;$\rho_1$&lt;/span&gt; as the density of box 1, and &lt;span class=&quot;math-container&quot;&gt;$\rho_2$&lt;/span&gt; as the density of box 2. We can calculate the capillary flow &lt;span class=&quot;math-container&quot;&gt;$q$&lt;/span&gt; as follows:&#xA;&lt;span class=&quot;math-container&quot;&gt;$q = k  \frac{(\rho_1 -\rho_2)}{\rho_0}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\rho_0$&lt;/span&gt; is the density when &lt;span class=&quot;math-container&quot;&gt;$T=T_0$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$S=S_0$&lt;/span&gt; such that &lt;span class=&quot;math-container&quot;&gt;$T_0=\frac{1}{2}(T_1+T_2)$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$S_0=\frac{1}{2}(S_1+S_2)$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Then, we can compute the density of each box as:&#xA;&lt;span class=&quot;math-container&quot;&gt;$\rho = \rho_0 (1 - \alpha (T-T_0) + \beta(S - S_0))$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;We can compute the capillary flow as:&#xA;&lt;span class=&quot;math-container&quot;&gt;$q = k(\alpha(T_2-T_1) + \beta(S_2-S_1))$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here, we know that, &lt;span class=&quot;math-container&quot;&gt;$\alpha = 1.5 * 10^{-4}$&lt;/span&gt; deg &lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$\beta = 8*10^{-4}$&lt;/span&gt; psu &lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt;, and &lt;span class=&quot;math-container&quot;&gt;$k = 1.5*10^{-6}$&lt;/span&gt; s &lt;span class=&quot;math-container&quot;&gt;$^{-1}$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;So far, this makes sense. What I am having a hard time wrapping my head around is the second piece of this leading to a system of differential equations (&lt;a href=&quot;https://i.stack.imgur.com/XS0UJ.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;see attached image showing how the system of differential equations were obtained&lt;/a&gt;). How do I find realistic values of c, H, and d? Where would I start? I tried looking at some published papers, which tend to still not give realistic values for these variables. Similarly, I am not sure what typical values of &lt;span class=&quot;math-container&quot;&gt;$\rho_0$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$T_1^{*}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$T_2^{*}$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$S_1^{*}$&lt;/span&gt;, and &lt;span class=&quot;math-container&quot;&gt;$S_2^{*}$&lt;/span&gt; should be. This is not for an assignment. I'm just trying to wrap my head around this model.&lt;/p&gt;&#xA;" OwnerUserId="29852" LastActivityDate="2023-10-21T02:22:02.630" Title="Understanding the parameters in Stommel's Two-Box Model (a model of ocean circulation based on temperature and salinity)" Tags="|ocean-models|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25677" PostTypeId="1" AcceptedAnswerId="25682" CreationDate="2023-10-21T02:27:43.733" Score="3" ViewCount="127" Body="&lt;p&gt;In this table of elastic constants, indices m = 1 and n = 4 result in negative values.  What could the reason be?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Tv4Os.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Tv4Os.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29829" LastEditorUserId="6298" LastEditDate="2023-10-21T15:01:19.777" LastActivityDate="2023-10-23T14:04:36.887" Title="What is the reason that some elastic constants are negative?" Tags="|geology|geophysics|geochemistry|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25678" PostTypeId="1" CreationDate="2023-10-21T11:29:53.530" Score="1" ViewCount="35" Body="&lt;p&gt;I know this isn't readily available. I know that it is 68% Northern Hemisphere vs 32% Southern. And I know that it's 68% Eastern vs 32% Western.&#xA;My wife asked me why I wanted to know and she got the same answer as always, I am just a curious man.&lt;/p&gt;&#xA;" OwnerUserId="29854" LastActivityDate="2023-10-21T11:29:53.530" Title="How much of the planet's land mass is between the Tropic of Cancer and Tropic of Capricorn" Tags="|geology|" AnswerCount="0" CommentCount="2" ClosedDate="2023-10-23T13:55:22.553" ContentLicense="CC BY-SA 4.0" />
  <row Id="25679" PostTypeId="1" CreationDate="2023-10-22T15:08:21.970" Score="4" ViewCount="54" Body="&lt;p&gt;I am looking for research trips on recent sediments (from about 1880) from the Central Downwelling Zones of the AMOC. The focus is on the regions: the Irminger Basin and the Labrador Basin.&lt;/p&gt;&#xA;&lt;p&gt;I especially need shells of foraminifera to determine &lt;sup&gt;18&lt;/sup&gt;O.&lt;/p&gt;&#xA;&lt;p&gt;Do you have an idea of a database that keeps such data or where I can see which expeditions have sampled in the two regions?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-02-21T09:25:51.700" LastActivityDate="2024-02-21T09:25:51.700" Title="Recent sediments from the Central Downwelling Zones of the AMOC" Tags="|ocean-currents|atlantic|amoc|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25680" PostTypeId="1" CreationDate="2023-10-22T22:27:41.760" Score="2" ViewCount="71" Body="&lt;p&gt;I saw something that mentioned how, during the 2018 World Cup, after a victory, thousand of fans jumping simultaneously caused seismologists to detect the equivalent energy release of a magnitude 2.0 earthquake. They then rhetorically posited the question, &amp;quot;What if the entire global population gathered in one place and did the same thing?&amp;quot;, but gave no answer. Therefore, I am wondering, is it possible to calculate, and if so what would be, the equivalent seismic magnitude of 8 billion people jumping?&lt;/p&gt;&#xA;" OwnerUserId="29859" LastEditorUserId="6298" LastEditDate="2023-10-22T23:12:47.293" LastActivityDate="2023-10-22T23:12:47.293" Title="Could humans cause an earthquake?" Tags="|earthquakes|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25681" PostTypeId="1" CreationDate="2023-10-23T09:19:32.090" Score="2" ViewCount="47" Body="&lt;p&gt;I am currently looking for data for a thesis. I wanted to ask which marine research institutes outside the European Union (USA, Canada, China, etc.) deal with the Arctic and/or the AMOC.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2023-10-23T09:19:32.090" Title="What are the central institutes that take care of Arctic research?" Tags="|sea-ice|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25682" PostTypeId="2" ParentId="25677" CreationDate="2023-10-23T14:04:36.887" Score="1" Body="&lt;p&gt;This looks like something unquestionably from a minerology textbook, the content of which I was never great at learning (or testing in). Regardless, here's my take on your info and question.&lt;/p&gt;&#xA;&lt;p&gt;First, make sure you understand 2 terms enough before proceeding: 1] indices (for a mineral) and 2] elastic constants (@f.thorpe's comment motivates this).&lt;/p&gt;&#xA;&lt;p&gt;Now that you have said terms defined in this context and know (approximately) what they mean, let's proceed with a simple, short take for an answer...&lt;/p&gt;&#xA;&lt;p&gt;When rocks (or more specifically minerals) are &amp;quot;deformed (i.e. &amp;quot;strained&amp;quot;) in labs, in earth, or seismic energy, they &amp;quot;compress&amp;quot; and/or &amp;quot;extended&amp;quot; in different ways (and directions). Now, here's where I carefully throw out an important and hard-to-pronounce-at-first term: &lt;strong&gt;mechanical anisotropy&lt;/strong&gt;. As a short answer, this is likely what's going on. However, for more info, read on...&lt;/p&gt;&#xA;&lt;p&gt;Anisotropy is basically everywhere. Optics, seismics, ...mechanics - you name it! For this example, though, it's the non-linear relationship between &amp;quot;stress&amp;quot; (i.e. &amp;quot;load&amp;quot;) and &amp;quot;strain&amp;quot; (again, a &lt;em&gt;ratio of deformation&lt;/em&gt; - keep in mind that it's unitless). Think of it this way: when I push the keys on my keyboard to try and provide an answer here, they are (at a very small scale) mechanically shortened vertically and extended laterally. However, if I did the same action with typing and instead the key compressed laterally (&lt;em&gt;whoa&lt;/em&gt;, don't believe me - &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/S0261306915002812&quot; rel=&quot;nofollow noreferrer&quot;&gt;here's a common material&lt;/a&gt; that does this), that could be quantified as negative elastic constant (note though that &amp;quot;elastic constant(s) is a general term includes a lot of more specific terms provided &lt;a href=&quot;https://se.copernicus.org/articles/11/259/2020/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;).&lt;/p&gt;&#xA;&lt;p&gt;If you examine that last link (even just the intro), I think that'll help guide more understanding here.&lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2023-10-23T14:04:36.887" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25684" PostTypeId="1" CreationDate="2023-10-23T19:15:25.257" Score="2" ViewCount="31" Body="&lt;p&gt;Generally dynamic modulus is greater then static modulus and experimental data matches that. But in chalcedonic limestone, the static modulus looks to be greater than the dynamic modulus. What could be the reason for this?&lt;/p&gt;&#xA;&lt;p&gt;And what exactly is dynamic modulus and static modulus? Is it same as Young's modulus?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/2nnnW.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2nnnW.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29829" LastEditorUserId="6298" LastEditDate="2023-10-24T06:19:17.667" LastActivityDate="2023-10-24T06:19:17.667" Title="Why is static modulus greater then dynamic modulus in limestone?" Tags="|geology|geophysics|geomorphology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25686" PostTypeId="1" CreationDate="2023-10-25T18:55:43.213" Score="2" ViewCount="28" Body="&lt;p&gt;In the given figure, which is plot of various elastic parameter for sand (blue) and shale(red) sequence. How to find Which crossplot has has greater sensitivity to lithology? Also what is mean by sensitivity in crossplots?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sAblm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sAblm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I have the following formula for  squared p impedance, s impedance and asked to show the sensitivity for rho mu vs lambda mu and p impedance vs s impedance is same ? How to show that?&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Ls1uc.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Ls1uc.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29829" LastActivityDate="2023-10-25T18:55:43.213" Title="How to compare sensitivity with lithology between different crossplots?" Tags="|geology|geophysics|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25687" PostTypeId="1" CreationDate="2023-10-27T19:52:43.670" Score="3" ViewCount="647" Body="&lt;p&gt;I need some guidance or clarification regarding the units for precipitation rate or precipitation intensity (esp. for rainfall). I'm used to precipitation intensity being expressed in &lt;em&gt;millimeters per hour&lt;/em&gt; (mm h&lt;sup&gt;-1&lt;/sup&gt;), but I noticed that reanalysis datasets generally express precipitation intensity in &lt;em&gt;kilogram per square meter per second&lt;/em&gt; (kg m&lt;sup&gt;-2&lt;/sup&gt; s&lt;sup&gt;-1&lt;/sup&gt;) which somehow confuses me.&lt;/p&gt;&#xA;&lt;p&gt;I've read somewhere that when converting from kg m&lt;sup&gt;-2&lt;/sup&gt; s&lt;sup&gt;-1&lt;/sup&gt; to mm h&lt;sup&gt;-1&lt;/sup&gt;, the values just have to be divided by 3600. And that in terms of precipitation amount/accumulation, 1 mm of rain is equal to 1  kg m&lt;sup&gt;-2&lt;/sup&gt;. I knew that it has something to do with liquid water having a density roughly equal to 1 kg L&lt;sup&gt;-1&lt;/sup&gt;, but the explanations were rushed so I'm still confused on how these two units are related to each other.&lt;/p&gt;&#xA;&lt;p&gt;So, I would like to ask: how exactly do we convert precipitation rate from kilogram per square meter per second (kg m&lt;sup&gt;-2&lt;/sup&gt; s&lt;sup&gt;-1&lt;/sup&gt;) to millimeter per hour (mm h&lt;sup&gt;-1&lt;/sup&gt;), and vice versa? How does the dimensional analysis for these units work out, and what is the conversion factor for this? In addition, how exactly do we also convert precipitation amount from mm to kg m&lt;sup&gt;-2&lt;/sup&gt;, and vice versa?&lt;/p&gt;&#xA;" OwnerUserId="29891" LastEditorUserId="2470" LastEditDate="2023-11-27T07:25:51.947" LastActivityDate="2024-03-15T19:53:27.863" Title="How to convert precipitation rate from kilogram per square meter per second (kg m-2 s-1) to millimeter per hour (mm h-1)?" Tags="|precipitation|rainfall|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25688" PostTypeId="2" ParentId="25687" CreationDate="2023-10-27T20:44:41.827" Score="1" Body="&lt;p&gt;Yes, this can be confusing, but let's take a look.  One kilogram of water is a volume equivalent to 1000 cubic centimeters of water.  How do we know that?  Well, each cc of water has a mass (or &lt;em&gt;standard&lt;/em&gt; equivalent weight) of 1 gram. Consequently, one kilogram of water will cover an area of 1000 square centimeters to a depth of 1 centimeter.  But wait (!), a square meter is 10 times the area of 1000 square centimeters.  Consequently, &lt;strong&gt;if&lt;/strong&gt; a 1-kg volume of water covering an area of 1000 square centimeters to a 1-centimeter depth were then spread out to cover a square meter of area 10,000 square centimeters (i.e ten times the area of 1000 square centimeters) the resulting depth would be one-tenth as great, &lt;em&gt;or just 1 mm.&lt;/em&gt;  That means that the volumetric rainfall rate given in liters, or kilograms, per square meter per second, is already given in equivalent linear measure in mm/sec.  But we want mm/hr.  Consequently, since an hour is 3600 seconds, we would multiply the rainfall &lt;em&gt;rate&lt;/em&gt; in kg/sq-m/sec by 3600 to get the rainfall &lt;em&gt;rate&lt;/em&gt; in mm/hr. The total rainfall would then be the rainfall rate in mm/hr times the number of hours for a total rainfall in mm.&lt;/p&gt;&#xA;&lt;p&gt;I think this covers what you were interested in knowing.&lt;/p&gt;&#xA;" OwnerUserId="29892" LastEditorUserId="29892" LastEditDate="2023-10-27T20:49:17.803" LastActivityDate="2023-10-27T20:49:17.803" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25691" PostTypeId="1" CreationDate="2023-10-30T01:52:08.747" Score="1" ViewCount="73" Body="&lt;p&gt;This is the example density depth functions for various sedimentary sections world wide. But someof the sections marked with red, due to their last term, as i increase the value of z(depth) they become negative. But density can never be negative? What could be other possible reason for &lt;a href=&quot;https://i.stack.imgur.com/KIOwa.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/KIOwa.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29829" LastActivityDate="2023-11-30T09:07:50.933" Title="What is the reason behind the density being negative value" Tags="|geology|geophysics|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25693" PostTypeId="1" CreationDate="2023-10-31T08:20:46.217" Score="2" ViewCount="40" Body="&lt;p&gt;I understand the Coriolis Effect, but how does that make the rising air cool 1/3 of the way to the poles, as opposed to non rotating Earth?&lt;/p&gt;&#xA;" OwnerUserId="29907" LastEditorUserId="2470" LastEditDate="2023-10-31T08:31:38.750" LastActivityDate="2023-10-31T08:31:38.750" Title="Three cell model of prevailing winds" Tags="|meteorology|wind|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25694" PostTypeId="2" ParentId="25691" CreationDate="2023-10-31T08:22:20.303" Score="3" Body="&lt;p&gt;You are looking at low order polynomial approximations of density. Such approximations are only valid over a certain range, typically the range over which the underlying data were collected. Applying the polynomial to a value well outside that range, which is what you are doing, is quite simply invalid. &amp;quot;Garbage in, garbage out.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Do not extrapolate.&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2023-10-31T08:22:20.303" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25696" PostTypeId="1" AcceptedAnswerId="25698" CreationDate="2023-10-31T15:02:27.047" Score="2" ViewCount="101" Body="&lt;p&gt;Casual learner only.&#xA;Decades ago, I read, one ocean scientist stated, jokingly, probably, &amp;quot;Give me half a shipload of iron filings and I will give you another ice age.&amp;quot; This was in response to the fact of iron being the only deficit in the southern ocean holding back phytoplankton growth. Some experiments did take place since then revealing a danger of toxic blooms and that the iron did not stay long enough in the upper ocean to have significant effect. But I find no continued investigations into stimulating phytoplankton growth despite it being such a major source of carbon absorption.&lt;/p&gt;&#xA;" OwnerUserId="29910" LastEditorUserId="2470" LastEditDate="2023-10-31T18:31:10.453" LastActivityDate="2023-10-31T18:32:17.903" Title="Can phytoplankton growth be stimulated in oceans to sequester CO2?" Tags="|co2|ocean-models|carbon-capture|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25698" PostTypeId="2" ParentId="25696" CreationDate="2023-10-31T17:40:03.080" Score="3" Body="&lt;p&gt;Research into the topic has been intermittent for a variety of reasons. &lt;a href=&quot;https://bg.copernicus.org/articles/15/5847/2018/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Ocean iron fertilization experiments – past, present, and future looking to a future Korean Iron Fertilization Experiment in the Southern Ocean (KIFES) project&lt;/a&gt; reviewed the status of research on the topic in 2018 and recommended ways the concept could be tested.&lt;/p&gt;&#xA;&lt;p&gt;The &amp;quot;iron hypothesis&amp;quot; put forth by John Martin in 1990 was that iron dust carried into the ocean accelerated historic ice ages by fertilizing phytoplankton which then captured enormous volumes of carbon dioxide, reducing the greenhouse effect -- iron being a key nutrient for phytoplankton. The suggestion followed that one could combat modern global warming by artificially fertilizing oceans with iron filings.&lt;/p&gt;&#xA;&lt;p&gt;The KIFES paper linked above and other sources suggest no credible scientific organization has wanted to conduct the large-scale experimentation and risk the potential ecological impacts and public disapproval to test out whether iron fertilization will have the desired sequestration effects, though &lt;a href=&quot;https://www.technologyreview.com/2023/02/15/1068495/these-startups-hope-to-spray-iron-particles-above-the-ocean-to-fight-climate-change/&quot; rel=&quot;nofollow noreferrer&quot;&gt;some startups such as Blue Dot Change plan to try on their own, according to MIT Technology Review&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastEditorUserId="2470" LastEditDate="2023-10-31T18:32:17.903" LastActivityDate="2023-10-31T18:32:17.903" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25700" PostTypeId="1" CreationDate="2023-10-31T21:20:34.577" Score="3" ViewCount="66" Body="&lt;p&gt;Is it always mandatory to perform a bias correction when working with CMIP6 climate projections?&lt;/p&gt;&#xA;&lt;p&gt;I am working with multiple climate projections from CMPI6 and I'm not sure if this step is necessary, even if I work with coarse (0.5 degrees) resolution.&lt;/p&gt;&#xA;" OwnerUserId="21719" LastActivityDate="2023-11-08T08:10:54.627" Title="Bias correction of CMIP6 projections" Tags="|models|climate-models|numerical-modelling|data-analysis|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25701" PostTypeId="1" CreationDate="2023-11-01T00:49:36.453" Score="1" ViewCount="21" Body="&lt;p&gt;I'm looking for a recent paper that demonstrates how one would unambiguously differentiate glauconite from berthierine and have yet to find something useful.&lt;/p&gt;&#xA;&lt;p&gt;I'm running across a lot of papers seeming to do this without explaining how they are going about it, an example being identification of berthierine as an alteration phase within authigenic glauconite grains. This wasn't the goal of the paper nor a key observation so I can understand why it would be skipped over or not explained in detail, but I need to find something definitive, or at least convincing, that demonstrates a method.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, a colleague of mine wrote a paper that identifies berthierine using only the 2.141A peak. However, it is my understanding that glauconite also has a 2.141A peak and the (001) basal reflection peak should be used to distinguish between the two instead. Again, need a citation for this, not a vague recollection, but some comments would be useful.&lt;/p&gt;&#xA;" OwnerUserId="29917" LastEditorDisplayName="user29779" LastEditDate="2023-11-01T20:17:05.423" LastActivityDate="2023-11-01T20:17:05.423" Title="Good modern paper demonstrating differentiation of glauconite and berthierine using xrd or FTIR" Tags="|geology|mineralogy|sedimentology|crystallography|spectral-analysis|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25702" PostTypeId="1" AcceptedAnswerId="25789" CreationDate="2023-11-01T09:20:12.213" Score="3" ViewCount="79" Body="&lt;p&gt;I have collection of images of synoptic weather charts downloaded from Bureau of Meteorology (&lt;a href=&quot;http://www.bom.gov.au/cgi-bin/charts/charts.view.pl?idcode=IDX0102&amp;amp;file=IDX0102.202001010000.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;BoM&lt;/a&gt;) which is in GIF format. I'm interested in obtaining the lat lon coordinates of cold fronts (thick black lines with triangles). My idea is: First get the pixel coordinates of the cold fronts. After obtaining the pixel coordinates, get the lat lon coordinates based on map projection type. &lt;a href=&quot;http://www.bom.gov.au/climate/austmaps/about-rain-maps.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;BoM&lt;/a&gt; website mentions that the map projection type is Lambert Conformal Conic (LCC) projection. How can I speed up obtaining the pixel coordinates? And how to get the exact lat lon coordinates?&lt;/p&gt;&#xA;&lt;p&gt;First, I approached extracting pixel coordinates in two ways:&lt;/p&gt;&#xA;&lt;p&gt;Manual:- Obtain the pixel coordinates using the ginput function of MATLAB where with the help of mouse cursor I got the pixel coordinates.&#xA;Image processing:- Converted the image into Binary and used edge and boundary detection. But in some cases this is not working properly.&lt;/p&gt;&#xA;&lt;p&gt;% CODE IMAGE PROCESSING %&lt;br /&gt;&#xA;img = imread('IDX0102.201501010000.gif');&lt;br /&gt;&#xA;binaryImage = imbinarize(img, 'adaptive');&lt;br /&gt;&#xA;edgeImage = edge(binaryImage, 'Canny');&lt;br /&gt;&#xA;BW2 = bwareaopen(img,3000);&lt;br /&gt;&#xA;contourData = bwboundaries(edgeImage);&lt;/p&gt;&#xA;&lt;p&gt;For obtaining lat lon coordinates based on LCC, I tried in MATLAB using pix2latlon function and also in python using the pyproj. None of them gives the expected results. How do I approach this problem?&lt;/p&gt;&#xA;" OwnerUserId="29923" LastActivityDate="2023-12-07T13:28:03.057" Title="How do I obtain latitude and longitude coordinates from synoptic weather charts" Tags="|coordinate-system|projection|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25703" PostTypeId="1" CreationDate="2023-11-02T21:41:41.747" Score="0" ViewCount="25" Body="&lt;p&gt;I understand the Wyllie time average equation&lt;a href=&quot;https://i.stack.imgur.com/jEqOC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jEqOC.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;How to extend it to multiple constituents ?&lt;/p&gt;&#xA;" OwnerUserId="29691" LastActivityDate="2023-11-02T21:41:41.747" Title="How to extend the Wyllie time average equation to multiple constituents" Tags="|geology|geophysics|rocks|structural-geology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25704" PostTypeId="2" ParentId="25113" CreationDate="2023-11-04T11:23:13.690" Score="2" Body="&lt;p&gt;The zero point of the enthalpy is based on gaseous air and  &lt;em&gt;liquid&lt;/em&gt; water at 0°C, whereas the water content in the air is &lt;em&gt;water vapor&lt;/em&gt;. So to get from the defined zero point to the actual state, you have to add the latent heat to get the water from liquid into vapor.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2023-11-04T11:23:13.690" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25705" PostTypeId="1" AcceptedAnswerId="25762" CreationDate="2023-11-04T11:28:47.783" Score="3" ViewCount="124" Body="&lt;p&gt;It is now standard practice to use foraminifera to represent paleo &lt;sup&gt;18&lt;/sup&gt;O signatures from a marine system. However, there are some problems if you want to show &lt;sup&gt;18&lt;/sup&gt;O variations in the last 100 years using foraminifera. One such problem is, for example, low sedimentation rate, growth in the stratification of a water column etc.&lt;/p&gt;&#xA;&lt;p&gt;Therefore, I wonder if there are any biological or geological indicators that can be used to show the change in the &lt;sup&gt;18&lt;/sup&gt;O signature of a marine system in recent times (since 1880)?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-03-12T01:49:02.840" LastActivityDate="2024-03-12T01:49:02.840" Title="What 18O indicators are there besides foraminifera?" Tags="|climate-change|oceanography|foraminifera|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25706" PostTypeId="2" ParentId="25604" CreationDate="2023-11-04T15:00:45.273" Score="2" Body="&lt;p&gt;While I cannot add anything to the etymological discussion. I would like to note that capital &lt;code&gt;U&lt;/code&gt; is the notation for relative humidity in the standard synoptic code known as SYNOP or FM-12, that is used around the world.&lt;/p&gt;&#xA;&lt;p&gt;According to &lt;a href=&quot;https://library.wmo.int/idurl/4/35713&quot; rel=&quot;nofollow noreferrer&quot;&gt;WMO Manual on codes&lt;/a&gt; known as WMO–No. 306 Volume I.1 – International Codes, Part A – Alphanumeric Codes, The symbols &lt;code&gt;UUU&lt;/code&gt; are used as placeholders for relative humidity of the air in SYNOP code, and symbols &lt;code&gt;U₁&lt;/code&gt;, &lt;code&gt;U₂&lt;/code&gt;, etc. are used in FM-88 code used to report satellite observations. The relative humidity group is defined under section 12.2.3.3.1.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Under unusual conditions, when the dew-point temperature is temporarily unavailable (e.g. because of instrument failure) but relative humidity is available, the group &lt;code&gt;29UUU&lt;/code&gt; shall replace the group &lt;code&gt;2SnTdTdTd&lt;/code&gt;. Every attempt shall first be made, however, to convert relative humidity to dew-point temperature, and the relative humidity included only as a&#xA;last resort.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So I would say that &lt;strong&gt;U&lt;/strong&gt; is used for relative humidity in instrument descriptions because it has become the established notation in international meteorological data exchange protocols.&lt;/p&gt;&#xA;&lt;p&gt;Each position in SYNOP is indicated by a single letter possibly with a subscript. One may ask, why meteorologists do not use &lt;strong&gt;Rh&lt;/strong&gt; for relative humidity. I guess this is because they already use &lt;strong&gt;R&lt;/strong&gt; to specify the amount of precipitation. I am almost sure that &lt;strong&gt;R&lt;/strong&gt; here stands for &lt;em&gt;rain&lt;/em&gt; as much of modern meteorological notation comes from the codes invented by Sir Francis Beaufort in the XIX century.&lt;/p&gt;&#xA;&lt;p&gt;The reason dew point temperature is preferred to relative humidity in weather records is that manual observation of humidity is usually performed using a psychrometer, a type of hygrometer composed of two thermometers of which one has its bulb kept dry and another has its bulb wet. Humidity is determined from the pair of readings of the two thermometers.&lt;/p&gt;&#xA;" OwnerUserId="2511" LastEditorUserId="2511" LastEditDate="2023-11-05T11:39:58.757" LastActivityDate="2023-11-05T11:39:58.757" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25707" PostTypeId="1" CreationDate="2023-11-04T19:05:35.597" Score="1" ViewCount="51" Body="&lt;p&gt;&lt;strong&gt;Water on our planet, where did it come from?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;A water molecule is created when two atoms of hydrogen combine with one atom of oxygen. W&lt;/p&gt;&#xA;&lt;p&gt;The volume of all water (on our planet) is about 332.5 million cubic miles (mi&lt;sup&gt;3&lt;/sup&gt;), or 1,386 million cubic kilometers (km&lt;sup&gt;3&lt;/sup&gt;). A cubic mile of water equals more than 1.1 trillion gallons. A cubic kilometer of water equals about 264 billion gallons (1 trillion liters)&#xA;&lt;a href=&quot;https://tinyurl.com/fxa4yn69&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://tinyurl.com/fxa4yn69&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;When the water on our planet was created, how much energy was released?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Check out “snowball earth”&lt;/strong&gt;&#xA;&lt;a href=&quot;https://tinyurl.com/4ym4s3v8&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://tinyurl.com/4ym4s3v8&lt;/a&gt;&#xA;&lt;a href=&quot;https://en.wikipedia.org/wiki/Snowball_Earth&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Snowball_Earth&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="20575" LastEditorUserId="2470" LastEditDate="2023-11-04T20:00:13.387" LastActivityDate="2023-11-04T20:00:13.387" Title="Water on our planet, where did it come from?" Tags="|meteorology|climate-change|oceanography|" AnswerCount="0" CommentCount="5" ClosedDate="2023-11-06T10:27:28.303" ContentLicense="CC BY-SA 4.0" />
  <row Id="25708" PostTypeId="2" ParentId="25641" CreationDate="2023-11-06T00:17:20.707" Score="2" Body="&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/JGg5q.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/JGg5q.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/EMus8.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/EMus8.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/xSntY.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/xSntY.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;These look like dried up lake beds or places where a river over flowed its banks.  Look along the edges of the area for details like old river beds, deltas or straight edges like a man made dam or even irrigation systems for farms. These edges look natural. If you look at the top of the first image, you can see to the far left and the far right that there is a river system connected to it. There are oxbows on the upper edge close to the right inlet. This is where the river folded back on itself creating a loop or a horseshoe shape. It's possible its a dry lake bed. A Google search on largest cities or towns may tell you more. Wiki may give place names for lakes or rivers for further searches.&lt;/p&gt;&#xA;&lt;p&gt;My Image 1 oxbow at location of question.&lt;/p&gt;&#xA;&lt;p&gt;My Image 2 color change due to detail change on zoom. Notice you start to see the shape of the dunes at the top? Its a lighter color and more detailed because that portion is zoomed in. The lower portion of the image is zoomed farther out and has a different color.&lt;/p&gt;&#xA;&lt;p&gt;In the second image you posted, you can see the same thing on the right of the dune area. The oxbow.&lt;/p&gt;&#xA;&lt;p&gt;Sometimes when you zoom in on Google earth the image will change color naturally due to distance (image 2 that I posted).&lt;/p&gt;&#xA;&lt;p&gt;Other times I've seen the same thing and tend to think that it was the time of day when the satellite passed over and took the images. It will look brighter like the sun is directly behind the satellite as opposed to sunrise or sunset.  This may not be so.&lt;/p&gt;&#xA;&lt;p&gt;Other times its a distortion in the imaging process, computers or communication issue with the satellite.  Maybe like the recent aurora borealis affect. Those can disrupt satellite communications that could potentially cause an image to not fully send from satellite or receive on earth.&lt;/p&gt;&#xA;&lt;p&gt;I've seen pixelated images that make you think its under surface archeology or something because its very squared off. (Third image I've posted.) You can see the blocky chunks. This is usually at the edge of a satellite image like this one off of Easter Island. On all the ocean edges I've looked at, its like this. The detail only goes out to a certain point. The ocean floor detail is from bathemtry research by science and military.&lt;/p&gt;&#xA;&lt;p&gt;Have fun Google earth searching, I certainly do!&lt;/p&gt;&#xA;" OwnerUserId="29944" LastEditorUserId="29944" LastEditDate="2023-11-06T00:27:03.540" LastActivityDate="2023-11-06T00:27:03.540" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25709" PostTypeId="2" ParentId="25536" CreationDate="2023-11-06T01:43:40.183" Score="2" Body="&lt;p&gt;When we have landmass between the mainland and the rest, the only applicable terms are exclave and enclave.&lt;/p&gt;&#xA;&lt;p&gt;For example, Kaliningrad is an exclave of Russia. Lesotho is an enclave of South Africa. Also, Uzbekistan has several exclaves inside Kyrgyzstan, which are enclaves for Kyrgyzstan itself. And several other examples.&lt;/p&gt;&#xA;&lt;p&gt;But when there is water between the mainland and the rest the only term is &lt;strong&gt;overseas territory&lt;/strong&gt;. Of course the distance should be very much so that the term applies.&lt;/p&gt;&#xA;&lt;p&gt;For instance, we don't call Sicily an overseas territory of Italy! But Azores is an overseas territory of Portugal. Also, Guam is an overseas territory of the USA. And several other examples.&lt;/p&gt;&#xA;&lt;p&gt;We don't have any terms for islands that are near the mainland; like Sicily, Isle of Man, etc.&lt;/p&gt;&#xA;" OwnerUserId="29082" LastEditorUserId="29082" LastEditDate="2023-11-06T12:52:52.837" LastActivityDate="2023-11-06T12:52:52.837" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25710" PostTypeId="1" CreationDate="2023-11-06T18:51:07.383" Score="2" ViewCount="232" Body="&lt;p&gt;Edit: this is a very silly question, sorry about that :/ I won't delete it though.&lt;/p&gt;&#xA;&lt;p&gt;When I was little and learned about the IDL, my first thought was the following: if I could do a couple of circles around the North Pole on a plane, then I would have to add several days to the calendar, and therefore I would be able to skip school days! &lt;/p&gt;&#xA;&lt;p&gt;While this is obviously not true, this means that the line stops making any sense directly near the poles, where one can cross it even by simply walking around the pole. I have stumbled upon a video about the IDL and suddenly remembered my childhood dreams of skipping school this way, and realized that I still don't quite understand why exactly does the concept of IDL break down.&lt;/p&gt;&#xA;&lt;p&gt;The problem is not latitude: if I go around the equator at 0.99c, I will cross the IDL 7 full times in 1 second, yet just one second would have passed (obviously ignoring relativistic effects), and consequently, there will be no need to adjust my calendar. Perhaps the problem is the angular velocity around the Earth's rotation axis? But if for slow speeds we adjust the day, and for fast ones we don't, then what happens in the middle? And how do polar expeditions keep track of time then?&lt;/p&gt;&#xA;&lt;p&gt;I'd be glad to see an explanation for all that.&lt;/p&gt;&#xA;" OwnerUserId="29949" LastEditorUserId="29949" LastEditDate="2023-11-12T16:21:19.880" LastActivityDate="2023-11-14T23:59:07.520" Title="When does the International Date Line concept break down?" Tags="|geography|time|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25711" PostTypeId="2" ParentId="25710" CreationDate="2023-11-06T19:02:25.270" Score="3" Body="&lt;p&gt;Time zones and the date line are associated with the geography, not the traveler. In practical and mechanical terms, you don't &amp;quot;gain&amp;quot; or &amp;quot;lose&amp;quot; days by crossing the date line repeatedly; you're just adjusting to the local time and date.&lt;/p&gt;&#xA;&lt;p&gt;In the Antarctic, for the sake of convenience, &lt;a href=&quot;https://en.wikipedia.org/wiki/Time_in_Antarctica&quot; rel=&quot;nofollow noreferrer&quot;&gt;the various research stations use whatever time zone is most useful for them&lt;/a&gt; for interacting with their home countries or other nations of interest. International (and scientific data) coordination generally standardizes on &lt;a href=&quot;https://en.wikipedia.org/wiki/Coordinated_Universal_Time&quot; rel=&quot;nofollow noreferrer&quot;&gt;Coordinated Universal Time (UTC)&lt;/a&gt;, formerly known as Greenwich Mean Time (GMT). In the Arctic, of course, there's no land at or near the pole.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2023-11-06T19:02:25.270" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25714" PostTypeId="1" CreationDate="2023-11-07T11:56:52.300" Score="0" ViewCount="104" Body="&lt;p&gt;When meteorological conditions are favorable for generally unlimited visibility, does that mean the atmosphere is sufficiently clear under these conditions that horizontal visibility is truly unlimited?  Or is there a limit to the distance we can see under such conditions?&lt;/p&gt;&#xA;" OwnerUserId="29957" LastEditorUserId="-1" LastEditDate="2023-11-16T08:06:25.343" LastActivityDate="2023-11-16T08:06:25.343" Title="What is the ultimate limit of horizontal visibility in Earth's atmosphere?" Tags="|earth-observation|" AnswerCount="1" CommentCount="3" ClosedDate="2023-11-10T10:47:46.033" ContentLicense="CC BY-SA 4.0" />
  <row Id="25715" PostTypeId="2" ParentId="25714" CreationDate="2023-11-07T14:52:08.463" Score="2" Body="&lt;p&gt;&lt;strong&gt;No.&lt;/strong&gt; Horizontal visibility, in essence the distance we could see in a horizontal direction, would simply fade into the distant haze. The ultimate distance we could likely see given exceptionally clear, daylight conditions, would be about 300 km, more or less, due to Rayleigh scattering.&lt;/p&gt;&#xA;" OwnerUserId="29958" LastActivityDate="2023-11-07T14:52:08.463" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25716" PostTypeId="2" ParentId="25700" CreationDate="2023-11-08T08:10:54.627" Score="3" Body="&lt;p&gt;It depends on your goal. So, you should ask yourself first which variables you're studying, what you're doing with them, and which kind of questions you want to ask afterwards.&lt;/p&gt;&#xA;&lt;p&gt;In general, CMIP6 data is found to be &lt;a href=&quot;https://iopscience.iop.org/article/10.1088/1748-9326/ab7e4f/meta&quot; rel=&quot;nofollow noreferrer&quot;&gt;less biased&lt;/a&gt; than CMIP5, although there are still enough biases to warrant &lt;a href=&quot;https://www.nature.com/articles/s41597-021-01079-3&quot; rel=&quot;nofollow noreferrer&quot;&gt;bias-adjusted datasets&lt;/a&gt;. However, both bias adjustment and downscaling can &lt;a href=&quot;https://www.authorea.com/doi/full/10.22541/essoar.168286894.44910061&quot; rel=&quot;nofollow noreferrer&quot;&gt;contribute to uncertainty&lt;/a&gt; in CMIP6, as has also been discussed for other climate model generations and set-ups. As a sidenote: in my opinion, &lt;a href=&quot;https://books.google.be/books?hl=nl&amp;amp;lr=&amp;amp;id=AMhJDwAAQBAJ&amp;amp;oi=fnd&amp;amp;pg=PP1&amp;amp;dq=maraun%20and%20widmann%202018&amp;amp;ots=3XyvwLtT7E&amp;amp;sig=quggRwundGBvkYMcMiGkhmPRvhE&amp;amp;redir_esc=y#v=onepage&amp;amp;q=maraun%20and%20widmann%202018&amp;amp;f=false&quot; rel=&quot;nofollow noreferrer&quot;&gt;the book by Maraun and Widmann (2018)&lt;/a&gt; still has one of the best discussion on uncertainty increase in climate projections. If you don't have access to the book, I've mentioned this discussion in &lt;a href=&quot;https://www.researchgate.net/publication/363565313_Bias_adjustment_of_climate_model_outputs_for_the_stochastic_generation_of_meteorological_variables_and_river_discharge&quot; rel=&quot;nofollow noreferrer&quot;&gt;my PhD thesis&lt;/a&gt;, see p.31.&lt;/p&gt;&#xA;&lt;p&gt;Thus, what should you do? I'd suggest you ask yourself the following questions, and look up the literature for some more information. In essence, do whatever is necessary, but only that. But note that the literature is not always conclusive.&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Do you need information at the same grid level as the projections?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;No: downscaling is necessary, but the best downscaling method for you issue is another question altogether. Afterwards, check the biases according to the steps given here (note that these steps may also be in the opposite order).&lt;/li&gt;&#xA;&lt;li&gt;Yes: look at the biases&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;ol start=&quot;2&quot;&gt;&#xA;&lt;li&gt;Are there, based on literature of a quick data analysis, biases present for the relevant variables?&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;No: great, you should be able to use the data as-is.&lt;/li&gt;&#xA;&lt;li&gt;Yes: go to question 3&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;ol start=&quot;3&quot;&gt;&#xA;&lt;li&gt;Are these biases relevant for your application? You should check literature on this, it always depends.&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;No: great, you can use the data as-is.&lt;/li&gt;&#xA;&lt;li&gt;Yes: apply bias adjustment. Think - again - from the perspective of your application, and choose the adjustment method accordingly.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="15226" LastActivityDate="2023-11-08T08:10:54.627" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25717" PostTypeId="1" CreationDate="2023-11-09T08:41:42.663" Score="2" ViewCount="90" Body="&lt;p&gt;I'm not sure where to ask this question, but I thought there might be people on this list who are familiar with rocks and minerals. I've been thinking about the first smelting of ore (which seems to have happened just twice in all of human history) and wondering how it happened. Possibly it was just an accident that someone built a campfire over a bit of lead ore and noticed the lead the next day, but how likely is that have happened twice? The alternative is that someone was experimenting with burning different rocks, and I'm wondering how likely that second possibility is. Are there enough rocks that would be interesting to burn that it would have seemed worthwhile to experiment?&lt;/p&gt;&#xA;&lt;p&gt;Do any rocks explode at campfire temperatures? That might have been fun to play with if not actually useful. Coal might actually make a practical campfire (does it?) so someone might have been looking for other rocks to use as fuel. Sulfur would make a terrible campfire but might be interesting. I've been able to find references to shale tar and shale oil which supposedly burn, but can't find out if they burn in a campfire or need higher temperatures. Are there other rocks that would be useful or interesting to throw in a campfire that stone-age people might have known about? Basically, would they have found enough different rocks that are interesting to burn that it might have prompted experiments?&lt;/p&gt;&#xA;" OwnerUserId="29971" LastActivityDate="2023-11-11T16:33:22.530" Title="Are there enough rocks that are useful to burn that Paleolithic people would have experimented with them?" Tags="|rocks|fire|history|" AnswerCount="2" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25718" PostTypeId="1" CreationDate="2023-11-09T15:34:41.147" Score="2" ViewCount="66" Body="&lt;p&gt;I'm trying to display cloud cover info by altitude from sounding data in a compact widget of an app for free-flight pilots. It's basically the vertical bar showing different shades of gray according to cloud probability in some Skew-T plots. I'd like to confirm my knowledge here and complete some missing bits. I understand there are 2 different processes generating clouds:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;1) Non-convective clouds&lt;/strong&gt; (name?): These are generated when air that is humid enough is (already) at an altitude where it is cold enough. This is where the dew point and the temp lines in a Skew-T plot are &amp;quot;close enough&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;2) Convective clouds:&lt;/strong&gt; These are generated by the condensation of water in humid air masses pushed up by convective forces to a cold enough layer above.&lt;/p&gt;&#xA;&lt;p&gt;Let's assume I have &lt;em&gt;pressure&lt;/em&gt;, &lt;em&gt;altitude&lt;/em&gt;, &lt;em&gt;temperature&lt;/em&gt; and &lt;em&gt;dew point&lt;/em&gt; series and the &lt;em&gt;floor altitude&lt;/em&gt; and &lt;em&gt;temperature&lt;/em&gt; (given insolation, etc.). If the above is &amp;quot;right enough&amp;quot;, I still need to know:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;For 1, non-convective:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;(i)&lt;/strong&gt; How close is &amp;quot;close enough&amp;quot; for the temp and DP at a given pressure (altitude) to conclude there can be clouds forming? I guess the answer is probabilistic so maybe there's some rule like 3 deg. is about 0% probability to 0 deg. being 100% probability. I can perfectly sacrifice a bit of precision in favor of simple calculations.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;(ii)&lt;/strong&gt; I'd also like to understand if these non-convective clouds, while condensing, may generate any updraft of air. If not I may split the bar to show clouds generating from each of the 2 processes. The whole point of the widget is to aid pilots deciding how close they can get to clouds without being sucked up. Flying inside clouds is not only normally forbidden, but can also be quite dangerous.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;For 2, convective:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I understand I'd need to simulate lifting the air directly in contact with the floor (at floor temp and the humidity given by the DP series at that altitude). It follows the dry adiabat (easy, constant number approx. is probably enough) until it saturates (when the floor DP = sounding temp), and from there (cloud base, LCL?) it follows the moist adiabat, which is my main doubt:&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;(iii)&lt;/strong&gt; I've found formulas for calculating the actual lapse rate (Gamma_w) but I'd need an integration of that, a function yielding temperature from pressure, given the initial pressure and temp of the parcel the moment it gets fully saturated. Something like&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;t[] = malr(p[], p0, t0)&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;essentially what you'd need to plot the MALR lines in the background of a Skew-T chart. My idea is to simulate the rising of the parcel and calculate the probability of clouds being at that level by comparing the simulation temps to the sounding temps (I think this is like calculating CAPE for a particular pressure).&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;(iv)&lt;/strong&gt; I'd also need to understand &amp;quot;how close&amp;quot; those temps need to be (or how to interpret this &amp;quot;CAPE for given pressure&amp;quot;) to derive percentage probabilities at every altitude.&lt;/p&gt;&#xA;&lt;p&gt;Am I going into the right direction? This problem is solved in each software showing clouds in their Skew-T plots. Just haven't been able to find it. Thanks in advance!&lt;/p&gt;&#xA;" OwnerUserId="29973" LastEditorUserId="29973" LastEditDate="2023-11-09T15:41:35.803" LastActivityDate="2024-02-18T22:03:25.420" Title="Drawing the cloud cover bar of Skew-T plot" Tags="|meteorology|weather-forecasting|clouds|storms|convection|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25719" PostTypeId="1" AcceptedAnswerId="25722" CreationDate="2023-11-09T18:21:33.320" Score="2" ViewCount="51" Body="&lt;p&gt;In some places in the world it can be observed that spots which used to be forest (or with the potential to become a forest) were changed to fields of solar panels.&lt;/p&gt;&#xA;&lt;p&gt;I've been close to solar panels on a sunny day on top of buildings and felt the warmth.  So I am wondering how much the near-ground average temperature rises when changing from a forested area.&lt;/p&gt;&#xA;" OwnerUserId="29976" LastEditorUserId="6298" LastEditDate="2023-11-10T08:46:53.947" LastActivityDate="2023-11-10T10:10:15.443" Title="Estimated surface average temperature rise when forest is replaced by solar panels" Tags="|climate-change|climate|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25720" PostTypeId="2" ParentId="25717" CreationDate="2023-11-09T18:53:14.007" Score="2" Body="&lt;p&gt;From what I was made aware of a long time ago, it appears your serendipitous camp fire hypothesis is thought to be plausible by some historians. The lack of written records makes it difficult to be certain.&lt;/p&gt;&#xA;&lt;p&gt;Through serendipity and then further experimentation using the same type, or similar rocks, over time people acquired the knowledge of which rocks would yield what metals.&lt;/p&gt;&#xA;&lt;p&gt;Occasionally, surprises were encountered, such as when what was thought to be copper mineralization gave a metal that was totally new, troublesome and initially of no use. The metal that was produced was called Nick's copper, or the Devil's copper, which later lead to the metal being called &lt;a href=&quot;https://en.wikipedia.org/wiki/Nickel&quot; rel=&quot;nofollow noreferrer&quot;&gt;nickel&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Nickel was first isolated and classified as an element in 1751 by Axel Fredrik Cronstedt, who initially mistook the ore for a copper mineral, in the cobalt mines of Los, Hälsingland, Sweden. The element's name comes from a mischievous sprite of German miner mythology, Nickel (similar to Old Nick).&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-11-09T18:53:14.007" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25722" PostTypeId="2" ParentId="25719" CreationDate="2023-11-10T10:10:15.443" Score="2" Body="&lt;p&gt;The answer is almost certainly 'depends'. The dependencies are a) around the forest - what kind of tree, what density of plants, what season? Then around the solar panels - how densely packed, how efficient etc? But we can make some estimates using albedo as a measure of the ratio of light reflected vs converted to heat.&lt;/p&gt;&#xA;&lt;p&gt;If a solar panel is 15% efficient that would be broadly equivalent to an albedo of 0.15 . &lt;a href=&quot;https://en.wikipedia.org/wiki/Albedo&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt; suggests that deciduous forest has an albedo of 0.15 to 0.18, with conifer forest varying from 0.09 to 0.18. This implies that replacing forest with solar panels shouldn't have a great effect on albedo.&lt;/p&gt;&#xA;&lt;p&gt;Albedo won't be the only effect on temperature as a forest will cool through evapotranspiration, which may reduce temperatures by more than 1 or 2 &lt;span class=&quot;math-container&quot;&gt;$^\circ$&lt;/span&gt;C. (Though a solar farm may well have grass under the panels which will also cool through evapotranspiration.)&lt;/p&gt;&#xA;&lt;p&gt;There will also be a perception effect - when you stand beside a solar panel the heat is released close to you, whereas if you were in a forest the bulk of radiated heat is going to be released in the canopy.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastActivityDate="2023-11-10T10:10:15.443" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25723" PostTypeId="1" AcceptedAnswerId="25725" CreationDate="2023-11-10T16:07:58.473" Score="3" ViewCount="75" Body="&lt;p&gt;With &lt;span class=&quot;math-container&quot;&gt;$u, v$&lt;/span&gt; denoting the components of wind velocity along zonal (x) and meridional (y) direction, atmospheric (relative) vorticity is usually defined by&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\zeta_z = \frac{\partial v}{\partial x} -\frac{\partial u}{\partial y} $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is the z-Component of the 3D-Vorticity, defined by&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\vec \zeta = \vec \nabla \times \vec v$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, atmospheric flow is not on a flat earth but on a sphere. E.g. a westerly wind follows the curved earth's surface and is better described in spherical coordinates. There, the vertical component of the 3D-vorticity is obtained by carrying out the curl operation in spherical coordinates (see &lt;a href=&quot;https://en.wikipedia.org/wiki/Del_in_cylindrical_and_spherical_coordinates&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;). This would give&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\zeta_z = \frac{1}{r \sin \theta } \left[ \frac{\partial }{\partial \theta} (u \sin \theta )  + \frac{\partial v}{\partial \varphi}\right]$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$u, v$&lt;/span&gt; are the local horizontal velocities along the unity vectors &lt;span class=&quot;math-container&quot;&gt;$\vec e_\varphi$&lt;/span&gt; (zonal) and &lt;span class=&quot;math-container&quot;&gt;$-\vec e_\theta$&lt;/span&gt; (meridonal). Note that here latitude &lt;span class=&quot;math-container&quot;&gt;$\theta $&lt;/span&gt; is measured from pole and not, as usual, from equator.&lt;/p&gt;&#xA;&lt;p&gt;By expanding this expression, we get&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\zeta_z = \frac{1}{r \sin \theta } \left[ \sin \theta \frac{\partial u }{\partial \theta}  + u \frac{\partial \sin \theta }{\partial \theta} + \frac{\partial v}{\partial \varphi}\right]$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;On the local tangential plane we have &lt;span class=&quot;math-container&quot;&gt;$dx = r \sin \theta d \varphi $&lt;/span&gt; and  &lt;span class=&quot;math-container&quot;&gt;$dy = -r d \theta $&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;so the derivatves with respect to &lt;span class=&quot;math-container&quot;&gt;$\varphi$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; can be replaced by derivates with respect to x and y. This gives finally:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\zeta_z = \frac{\partial v}{\partial x} - \frac{\partial u}{\partial y} + \frac{u}{r} \cdot \frac{\cos \theta}{\sin\theta} $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;which is clearly not in accordance with the first equation: There is an extra term proportional to u. Why do we have this discrepancy and why is this not mentioned in standard textbooks?&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2023-11-10T17:50:53.617" LastActivityDate="2023-11-11T12:52:40.300" Title="Why does relative vorticity in spherical coordinates have an extra term as compared to the usual cartesian derivation?" Tags="|meteorology|atmosphere|fluid-dynamics|atmospheric-circulation|vorticity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25725" PostTypeId="2" ParentId="25723" CreationDate="2023-11-11T10:56:53.807" Score="2" Body="&lt;p&gt;The best way to see this extra term is to consider a bug moving along a latitude circle at constant speed &lt;span class=&quot;math-container&quot;&gt;$|u|$&lt;/span&gt; in a constant direction arounf the poles. If the bug is moving along a geodesic then there is no vorticity, but the latitude circle is not a geodesic except at the Equator (&lt;span class=&quot;math-container&quot;&gt;$\cos\theta=0$&lt;/span&gt;). So movement along any other latitude circle will entail some vorticity, even with the vector components remaining constant.&lt;/p&gt;&#xA;&lt;p&gt;The vorticity term with no component gradients has two additional features. First, we see that it is an odd function of displacement from the Equator; the Northern and Southern Hemispheres give opposite signs. This corresponds to the latitude circle deviating in opposite ways from the geodesic in the two hemispheres. If the &amp;quot;bug&amp;quot; in our example were to be taken as following the rotation of Earth itself, it would appear to be turning clockwise if it were seen from the South Pole (so it woukd be in the Southern Hemisphere) but counterclockwise if seen from the North Pole.&lt;/p&gt;&#xA;&lt;p&gt;Second, the term goes to infinity as we approach either pole (&lt;span class=&quot;math-container&quot;&gt;$\sin\theta\to0$&lt;/span&gt;). The closer our bug gets to a pole, tge more angular velocity it would need to attain a given nonzero target &lt;span class=&quot;math-container&quot;&gt;$u$&lt;/span&gt; value, and the vorticity in the absence of gradients follows suit. Natural motions near the pole a spherical body (including Earth) either have decreased speed in the latitude direction (balancing out the increased &lt;span class=&quot;math-container&quot;&gt;$\cot\theta$&lt;/span&gt; factor) or quickly move away from the pole (the vorticity is then balanced out by nonzero derivative terms).&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2023-11-11T12:52:40.300" LastActivityDate="2023-11-11T12:52:40.300" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25726" PostTypeId="2" ParentId="21236" CreationDate="2023-11-11T14:27:47.680" Score="0" Body="&lt;p&gt;On Earth, around 13,000 oscillations can be measured in the frequency range 1 &lt;span class=&quot;math-container&quot;&gt;$\mu$&lt;/span&gt;Hz to around 200 &lt;span class=&quot;math-container&quot;&gt;$\mu$&lt;/span&gt;Hz. A very strong peak is observed at 22.3643 &lt;span class=&quot;math-container&quot;&gt;$\mu$&lt;/span&gt;Hz. At this frequency the moon deforms the earth and the atmosphere (tides). The moon, the sun and the planets generate further, much weaker resonance frequencies, which are precisely known and tabulated in The HW95 tidal potential catalogue,&#xA;&lt;a href=&quot;https://publikationen.bibliothek.kit.edu/160395&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://publikationen.bibliothek.kit.edu/160395&lt;/a&gt;. A spectrum can be found in &lt;a href=&quot;https://vixra.org/abs/2311.0020&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://vixra.org/abs/2311.0020&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29994" LastEditorUserId="29994" LastEditDate="2023-11-11T14:28:21.543" LastActivityDate="2023-11-11T14:28:21.543" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25728" PostTypeId="1" CreationDate="2023-11-11T14:38:25.323" Score="2" ViewCount="47" Body="&lt;p&gt;I noticed Earth has variations in gravity similar to focal points for magnetic fields, both macro and micro in size, caused by magnetic material deposits. With oxygen being attracted to magnets, I wonder if the concentration of oxygen on Earth is greater where the magnetic field is stronger?&lt;/p&gt;&#xA;" OwnerUserId="21150" LastEditorUserId="6298" LastEditDate="2023-11-12T10:47:43.323" LastActivityDate="2023-11-12T10:47:43.323" Title="Does oxygen propagate towards stronger magnetic fields on Earth?" Tags="|geomagnetism|oxygen|electromagnetism|magnetosphere|ore|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25729" PostTypeId="2" ParentId="25717" CreationDate="2023-11-11T16:33:22.530" Score="0" Body="&lt;p&gt;**greetings.  This answer is predicated on the information I gleaned as the son of a Kennecott Copper Corp. engineer,  and metallurgist.&lt;/p&gt;&#xA;&lt;p&gt;It was said, then, (50+ years ago) that copper was mined by aboriginal people at least 6,000 years ago, according to anthropologists,  primarily because&amp;quot;native copper&amp;quot; could be recognized by them in attractive deposits that required a minimal amount of smelting in order to provide a material for crafts etc..&#xA;(It was hypothesized that the related amount of lead and zinc likely contributed to non-OSHA approved air quality in the vicinity, but that's a different story.)&lt;/p&gt;&#xA;" OwnerUserId="29995" LastActivityDate="2023-11-11T16:33:22.530" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25730" PostTypeId="1" AcceptedAnswerId="25733" CreationDate="2023-11-12T16:53:15.167" Score="2" ViewCount="239" Body="&lt;p&gt;When watching news about earthquakes, I think most people are used to hear about the &lt;a href=&quot;https://en.wikipedia.org/wiki/Richter_scale&quot; rel=&quot;nofollow noreferrer&quot;&gt;Richter scale&lt;/a&gt;, a logarithmic scale used to measure earthquake intensity. A very strong earthquake, like the &lt;a href=&quot;https://en.wikipedia.org/wiki/2011_T%C5%8Dhoku_earthquake_and_tsunami&quot; rel=&quot;nofollow noreferrer&quot;&gt;2011 one&lt;/a&gt; leading to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Fukushima_nuclear_accident&quot; rel=&quot;nofollow noreferrer&quot;&gt;Fukushima meltdown&lt;/a&gt;, happens about a couple times per century, and ranks over 9.0 in this scale. Small ones happen all the time. For example, here in Brazil we had &lt;a href=&quot;https://moho.iag.usp.br/eq/event/usp2023vrca&quot; rel=&quot;nofollow noreferrer&quot;&gt;one recorded a few days ago, at 2023-11-05&lt;/a&gt; in Bahia state, ranking 2.7 in this scale.&lt;/p&gt;&#xA;&lt;p&gt;A less know fact is that we can calculate an energy equivalent for an earthquake, from its Richter magnitude. &lt;a href=&quot;https://www.wolframalpha.com/input?i=earthquake%20energy%20formula&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wolframalpha&lt;/a&gt; gives us the following formula to calculate it:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ E = 10^{1.5M + 4.8} $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Where E is energy, in joules, and M the Richter magnitude.&lt;/p&gt;&#xA;&lt;p&gt;Using this formula I wrote a small Python script to calculate energies over the scale, but in &lt;a href=&quot;https://en.wikipedia.org/wiki/TNT_equivalent&quot; rel=&quot;nofollow noreferrer&quot;&gt;tons of TNT equivalent&lt;/a&gt;, a unit typically used to describe the energy released in explosions, together with its multiples (kiloton = 1000 tons, megaton = 1,000,000 tons, &lt;em&gt;et cetera&lt;/em&gt;):&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;ton = 4.184e9 #One ton of TNT corresponds to 4.184 billion joules&#xA;&#xA;for i in range(2, 20):&#xA;    print('Richter',&#xA;          (richter_magnitude := i/2),&#xA;          '~=',&#xA;          round(pow(10, 1.5*richter_magnitude + 4.8)/ton, 3),&#xA;          'tons of TNT.')&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Running it I got these results:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;Richter 1.0 ~= 0.0 tons of TNT.&#xA;Richter 1.5 ~= 0.003 tons of TNT.&#xA;Richter 2.0 ~= 0.015 tons of TNT.&#xA;Richter 2.5 ~= 0.085 tons of TNT.&#xA;Richter 3.0 ~= 0.477 tons of TNT.&#xA;Richter 3.5 ~= 2.682 tons of TNT.&#xA;Richter 4.0 ~= 15.08 tons of TNT.&#xA;Richter 4.5 ~= 84.802 tons of TNT.&#xA;Richter 5.0 ~= 476.879 tons of TNT.&#xA;Richter 5.5 ~= 2681.688 tons of TNT.&#xA;Richter 6.0 ~= 15080.242 tons of TNT.&#xA;Richter 6.5 ~= 84802.435 tons of TNT.&#xA;Richter 7.0 ~= 476879.138 tons of TNT.&#xA;Richter 7.5 ~= 2681688.466 tons of TNT.&#xA;Richter 8.0 ~= 15080242.459 tons of TNT.&#xA;Richter 8.5 ~= 84802435.285 tons of TNT.&#xA;Richter 9.0 ~= 476879138.377 tons of TNT.&#xA;Richter 9.5 ~= 2681688466.305 tons of TNT.&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;With this data now we can compare earthquakes to explosive power. For example, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Little_Boy&quot; rel=&quot;nofollow noreferrer&quot;&gt;nuclear weapon&lt;/a&gt; used to &lt;a href=&quot;https://en.wikipedia.org/wiki/Atomic_bombings_of_Hiroshima_and_Nagasaki&quot; rel=&quot;nofollow noreferrer&quot;&gt;level Hiroshima&lt;/a&gt; released an estimated energy (yield) of 15,000 tons (15 kilotons). In the table we see this is roughly the energy of an earthquake of 6.0 Richter magnitude. The first hydrogen bomb ever detonated in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Castle_Bravo&quot; rel=&quot;nofollow noreferrer&quot;&gt;Castle Bravo&lt;/a&gt; test had an estimated yield a thousand times higher, 15 megatons, worth close to a magnitude 8.0 in our table. In &lt;a href=&quot;https://physics.stackexchange.com/a/770120/266085&quot;&gt;a answer&lt;/a&gt; I gave previously to &lt;a href=&quot;https://physics.stackexchange.com/q/769418/266085&quot;&gt;a question&lt;/a&gt; in the physics stackexchange, I estimated the implosion energy of the failed &lt;a href=&quot;https://en.wikipedia.org/wiki/Titan_submersible_implosion&quot; rel=&quot;nofollow noreferrer&quot;&gt;Titan submersible expedition&lt;/a&gt; at roughly 30kg TNT equivalent, or 0.03 tons, corresponding to a small quake between 2.0 and 2.5 magnitude.&lt;/p&gt;&#xA;&lt;p&gt;Now, for the last weeks I'm following the harrowing news and social media posts documenting the ongoing &lt;a href=&quot;https://en.wikipedia.org/wiki/2023_Israeli_invasion_of_the_Gaza_Strip&quot; rel=&quot;nofollow noreferrer&quot;&gt;Gaza Strip siege&lt;/a&gt;. Amidst all the human suffering there, one thing that impressed me was the degree of buildings destruction by air raids and shelling, with imagery reminiscent of post-apocalyptic movies, or historical photos from &lt;a href=&quot;https://en.wikipedia.org/wiki/World_War_II&quot; rel=&quot;nofollow noreferrer&quot;&gt;World War II&lt;/a&gt;, as shown in those before and after satellite images (&lt;a href=&quot;https://twitter.com/wammezz/status/1717469105471524965&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vvUkU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vvUkU.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/zygRX.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zygRX.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/wjpPL.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/wjpPL.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/nvQKF.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nvQKF.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;A new analysis by two United States-based researchers, Jamon Van Den&#xA;Hoek and Corey Scher, and Al Jazeera’s AJ Labs unit showed that&#xA;overall at least 16 percent of all buildings in the Gaza Strip have&#xA;been destroyed. In Gaza City alone, the building destruction reached&#xA;at least 28 percent.&lt;/p&gt;&#xA;&lt;p&gt;According to the latest data from the United Nations Office for the&#xA;Coordination of Humanitarian Affairs (OCHA), the World Health&#xA;Organization (WHO) and the Palestinian government, and as of November&#xA;7, Israeli attacks have damaged at least 222,000 residential units,&#xA;with more than 40,000 completely destroyed. (&lt;a href=&quot;https://www.aljazeera.com/news/2023/11/10/israeli-bombardments-damage-more-than-half-of-gazas-housing-units&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Despite no nuclear weapons being used &lt;a href=&quot;https://www.newsweek.com/amichai-eliyahu-nuclear-threat-draws-outraged-rebuke-saudi-arabia-1840989&quot; rel=&quot;nofollow noreferrer&quot;&gt;so far&lt;/a&gt;, the sheer amount of conventional chemical explosives already dropped there is impressive. As of November 9, 2023:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;According to the Euro-Med Human Rights Monitor, Israel has dropped&#xA;more than 25,000 tonnes of explosives on the Gaza Strip since October&#xA;7, equivalent to two nuclear bombs.&lt;/p&gt;&#xA;&lt;p&gt;In comparison, the Little Boy nuclear bomb dropped by the United&#xA;States on Hiroshima during World War II yielded 15,000 tonnes of high&#xA;explosives and destroyed everything within a one-mile (1.6km) radius.&#xA;(&lt;a href=&quot;https://www.aljazeera.com/news/longform/2023/11/9/israel-attacks-on-gaza-weapons-and-scale-of-destruction&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Some of the individual bombs used are quite large, leaving craters over 10 meters wide, as shown in this photo of the aftermath of an air raid in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Jabalia_refugee_camp&quot; rel=&quot;nofollow noreferrer&quot;&gt;Jabalia refugee camp&lt;/a&gt; (&lt;a href=&quot;https://www.bellingcat.com/news/2023/10/31/confirming-a-strike-on-jabalia-refugee-camp-as-israeli-forces-approach-gaza-city/&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;):&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/O6VOW.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/O6VOW.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;But a visual analysis by the Guardian has identified at least five&#xA;craters in the densely populated refugee camp, which weapons experts&#xA;said were left by the use of multiple JDAMs – &lt;a href=&quot;https://en.wikipedia.org/wiki/Joint_Direct_Attack_Munition&quot; rel=&quot;nofollow noreferrer&quot;&gt;joint direct attack&#xA;munitions&lt;/a&gt; – in the airstrike.&lt;/p&gt;&#xA;&lt;p&gt;Marc Garlasco, a former Pentagon chief of high value targeting during&#xA;the Iraq war in 2003, told the Guardian the biggest crater at the site&#xA;looked like a hit with a GBU-31. “There are other bombs it could be.&#xA;That one just fits best with all the evidence. The estimated crater is&#xA;around 40ft [12 metres].”&lt;/p&gt;&#xA;&lt;p&gt;Chris Cobb-Smith, a former United Nations weapons inspector, said:&#xA;“The munition is almost certainly JDAM, either a GBU 31 (Warhead Mark&#xA;84) general purpose bomb or possibly a GBU 56 (Warhead BLU 109) bunker&#xA;buster. Both about 2,000lb [900kg].” (&lt;a href=&quot;https://www.theguardian.com/world/2023/nov/01/jabalia-camp-airstrike-gaza&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So, with individual bombs containing from at least a hundred of kilograms of explosives, up to a ton, I think we should expect resulting tremors from air raids ranging approximately from 2.0 up to 3.5 in the Richter scale, according to our table.&lt;/p&gt;&#xA;&lt;p&gt;So I ask, are seismometers over the world able to record the small earthquakes generated by these explosions? Is their sensibility enough to count or pinpoint individual strikes, or at least to record the noise? Another thing I wonder is if all this noise interfere with real earthquake detection.&lt;/p&gt;&#xA;" OwnerUserId="29988" LastEditorUserId="30066" LastEditDate="2023-11-21T20:05:33.920" LastActivityDate="2023-11-21T20:05:33.920" Title="Are seismometers over the world &quot;feeling&quot; the small earthquakes caused by air raids and shelling on Gaza Strip?" Tags="|earthquakes|seismology|remote-sensing|earth-observation|induced-seismicity|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25732" PostTypeId="2" ParentId="25710" CreationDate="2023-11-13T02:05:33.610" Score="1" Body="&lt;p&gt;Something to keep in mind about the International Date Line, or any time zone boundary, is that it is a human construct meant to help delineate an area of equal time for the local residents.  I'm not exactly sure what you are asking in your question, but traveling only requires that you change your clock when you reach your destination, not during transit.  It should be noted that the time zone map in Antarctica is already adjusted to account for the &amp;quot;polar time&amp;quot; phenomenon you are worried about.  See below, where it shows the polar area using one time zone. I don't think the North Pole has anything like this, because there is no land or &amp;quot;local area&amp;quot;, so sailors can just &lt;a href=&quot;https://www.sciencefocus.com/planet-earth/what-time-zones-are-used-at-the-north-pole-and-south-pole&quot; rel=&quot;nofollow noreferrer&quot;&gt;use whatever time zone they wish&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/pIgND.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/pIgND.png&quot; alt=&quot;Map of approximate time zones on the continent of Antarctica. Stations could use time zones not matching the map. From Wikipedia&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2023-11-13T02:17:28.530" LastActivityDate="2023-11-13T02:17:28.530" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25733" PostTypeId="2" ParentId="25730" CreationDate="2023-11-14T21:58:55.943" Score="6" Body="&lt;p&gt;Bomb explosions are detectable as seismic events, but the energy falls off with distance, so for quakes of less than magnitude 3 you'd have to be with a few 10s of kilometers, depending on your equipment.&lt;/p&gt;&#xA;&lt;p&gt;The closest such equipment would be part of the Israel Seismic Network and its map at &lt;a href=&quot;https://eq.gsi.gov.il/en/earthquake/lastEarthquakes.php&quot; rel=&quot;noreferrer&quot;&gt;https://eq.gsi.gov.il/en/earthquake/lastEarthquakes.php&lt;/a&gt; of the last 30 quakes in the region isn't currently showing anything in Gaza.&lt;a href=&quot;https://i.stack.imgur.com/HvQZf.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/HvQZf.png&quot; alt=&quot;map of the eastern Mediterranean Sea and the surrounding land regions showing earthquakes of magnitude 2 or greater, none near Gaza&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Individual bomb blasts are also short bursts of energy on the surface, often on top of or into compacted earth, unlike seismic activity which is commonly a large, longer release at depth along a faultline radiating through rock. A nuclear weapon, for example, has a much different seismic signature from the equivalent amount of TNT or modern high explosives.&lt;/p&gt;&#xA;" OwnerUserId="7314" LastActivityDate="2023-11-14T21:58:55.943" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25734" PostTypeId="2" ParentId="25710" CreationDate="2023-11-14T23:59:07.520" Score="2" Body="&lt;p&gt;The key is recognizing that as you walk around the pole, you not only cross the IDL. You cross all the other time zone boundaries that also converge to the pole. If you are going east so that you set your date back at the IDL, then you are setting your clock time forward hour by hour as you cross the other time zone boundaries. The net result is that the backwards time increment you got at the IDL is balanced out by the forward increments at all the other boundaries, so the only net time change is the (forward) time you took to make the lap. The same holds true, with signs reversed for the boundary crossings, if you walk westwards around the pole. Therefore the IDL may be rendered all the way from pole to pole without creating any apparent &amp;quot;time travel&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2023-11-14T23:59:07.520" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25735" PostTypeId="1" CreationDate="2023-11-15T07:31:19.543" Score="2" ViewCount="116" Body="&lt;p&gt;Sometimes, people say things like &amp;quot;It's only &lt;span class=&quot;math-container&quot;&gt;$5^\circ\mathrm{C}$&lt;/span&gt; outside, but there is a warm wind, and it feels much warmer&amp;quot; (I live in Austria, a region where there are &lt;em&gt;Föhn&lt;/em&gt; winds). I have a hard time agreeing to such statements, and I think they might not be correct. In the following, assume a cloudy day, so that we may ignore the effect of the sun, which is hard to quantify. Relevant aspects I am aware of are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;First of all, the air has a measurable temperature (the &lt;span class=&quot;math-container&quot;&gt;$5^\circ\mathrm{C}$&lt;/span&gt;). That one is unique (i.e. there is no second, &amp;quot;intrinsic&amp;quot; temperature that appears in the warm wind).&lt;/li&gt;&#xA;&lt;li&gt;There is the concept of &amp;quot;&lt;a href=&quot;https://en.wikipedia.org/wiki/Apparent_temperature&quot; rel=&quot;nofollow noreferrer&quot;&gt;apparent temperature&lt;/a&gt;&amp;quot;, which factors in humidity and wind chill. Generally, this is used to explain why the &amp;quot;feels-like&amp;quot; temperature is &lt;em&gt;lower&lt;/em&gt; than the one measured by the thermometer.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;Question&lt;/strong&gt;: Are there other factors that I am missing that might make the wind appear &amp;quot;warmer&amp;quot; (than the temperature shown on the thermometer)? Something that would justify a statement like this: &amp;quot;The thermometer shows &lt;span class=&quot;math-container&quot;&gt;$5^\circ\mathrm{C}$&lt;/span&gt;, but it &lt;em&gt;feels&lt;/em&gt; like &lt;span class=&quot;math-container&quot;&gt;$10^\circ\mathrm{C}$&lt;/span&gt;&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Explanation attempt&lt;/strong&gt;: Consider a couple of days, all with a measured temperature of &lt;span class=&quot;math-container&quot;&gt;$5^\circ\mathrm{C}$&lt;/span&gt;, and for most days, the humidity is at &lt;span class=&quot;math-container&quot;&gt;$50\%$&lt;/span&gt;, except for one day, where it is at &lt;span class=&quot;math-container&quot;&gt;$80\%$&lt;/span&gt;. Then the latter day would appear warmer than the other days:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;On low-humidity days, the apparent (&amp;quot;feels like&amp;quot;) temperature would be lower than &lt;span class=&quot;math-container&quot;&gt;$5^\circ\mathrm{C}$&lt;/span&gt;.&lt;/li&gt;&#xA;&lt;li&gt;On the high-humidity day, the apparent temperature would be close to the actual &lt;span class=&quot;math-container&quot;&gt;$5^\circ\mathrm{C}$&lt;/span&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;In comparison, the high-humidity day will feel warm. It's not so much that it feels warmer than &lt;span class=&quot;math-container&quot;&gt;$5^\circ\mathrm{C}$&lt;/span&gt;, but that the low-humidity days feel cooler than &lt;span class=&quot;math-container&quot;&gt;$5^\circ\mathrm{C}$&lt;/span&gt;. But I am not sure if this argument actually holds up, since the effect of humidity on humans is mostly due to perspiration, and it is much greater for higher temperatures.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Follow-up question&lt;/strong&gt;: Would you agree with this, or are there other explanations?&lt;/p&gt;&#xA;" OwnerUserId="30019" LastEditorUserId="30019" LastEditDate="2023-11-15T09:43:18.660" LastActivityDate="2023-11-15T09:43:18.660" Title="Is there such a thing as a &quot;warm wind&quot;?" Tags="|temperature|humidity|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25737" PostTypeId="1" CreationDate="2023-11-16T00:15:34.747" Score="5" ViewCount="50" Body="&lt;p&gt;The Iceland Met Office website has a status page at &lt;a href=&quot;https://en.vedur.is/about-imo/news/a-seismic-swarm-started-north-of-grindavik-last-night&quot; rel=&quot;noreferrer&quot;&gt;https://en.vedur.is/about-imo/news/a-seismic-swarm-started-north-of-grindavik-last-night&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It has mentioned using models to determine the location and size of the magma body which is threatening to erupt in the vicinity of Grindavík and the Blue Lagoon. They have also published estimates for the inflow rate of new magma into the linear chamber.&lt;/p&gt;&#xA;&lt;p&gt;How do they determine these things? What data are the estimates based upon? How confident are geologists in the model outputs?&lt;/p&gt;&#xA;" OwnerUserId="26208" LastActivityDate="2023-11-16T00:15:34.747" Title="How have Icelandic geologists determined the position and length of the magma under Grindavík?" Tags="|volcanology|models|volcanic-eruption|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25738" PostTypeId="1" CreationDate="2023-11-16T16:34:09.233" Score="2" ViewCount="90" Body="&lt;p&gt;According to &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_internal_heat_budget&quot; rel=&quot;nofollow noreferrer&quot;&gt;Earth's internal heat budget&lt;/a&gt; (Wikipedia) “About 50% of the Earth's internal heat originates from radioactive decay”.&lt;/p&gt;&#xA;&lt;p&gt;However, this makes up only a small portion of the Earth’s heat budget due to the large input of solar heating.&lt;/p&gt;&#xA;&lt;p&gt;How much cooler would the Earth’s surface be if there was no contribution from radiogenic heating?&lt;/p&gt;&#xA;" OwnerUserId="24794" LastEditorUserId="18088" LastEditDate="2023-11-17T16:57:52.333" LastActivityDate="2023-11-20T17:52:14.180" Title="How much cooler would the Earth’s surface be if there was no contribution from radiogenic heating?" Tags="|climate-change|temperature|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25740" PostTypeId="1" CreationDate="2023-11-17T13:21:24.090" Score="3" ViewCount="45" Body="&lt;p&gt;I am analyzing ERA5 climate data spanning from 1950 to 2023, covering 73 years. The dataset has a daily temporal resolution and a spatial resolution of 0.25° (1440 x 720).&lt;/p&gt;&#xA;&lt;p&gt;Each yearly data is stored in a NetCDF file, containing approximately 365 layers.&lt;/p&gt;&#xA;&lt;p&gt;Attempting to combine these into a single stack results in around 27000 layers, which is overwhelming for my computer, and even the workplace cluster struggles with this volume.&lt;/p&gt;&#xA;&lt;p&gt;As I'm new to handling large-scale datasets, I'm seeking advice on best practices and effective solutions for managing and processing this type of data.&lt;/p&gt;&#xA;&lt;p&gt;Note: I have a preference for working with dataframes over NetCDF files as I will perform time series analysis.&lt;/p&gt;&#xA;&lt;p&gt;Note 2: different types of analysis will be performed in the future. It's very wide: from simple statistics, to indices computations etc. On a grid cell level. So far, I am handling precipitation Prec and PET data to calculate a cumulative water deficit for each grid cell, followed by identifying the maximum deficit values annually, then conducting an extreme value analysis. But I would do other type of analysis in the future.&lt;/p&gt;&#xA;" OwnerUserId="29990" LastEditorUserId="29990" LastEditDate="2023-11-17T13:22:52.930" LastActivityDate="2023-11-17T13:22:52.930" Title="Handling large-scale climate dataset in R" Tags="|climate|netcdf|r|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25742" PostTypeId="1" AcceptedAnswerId="25910" CreationDate="2023-11-18T10:48:21.760" Score="4" ViewCount="86" Body="&lt;p&gt;Reading &lt;a href=&quot;https://earthscience.stackexchange.com/a/25733/6298&quot;&gt;jeffronicus' answer about how seismic stations record bomb explosions&lt;/a&gt;,  particularly the reminder that the intensity of earthquakes drops by distance, made me start wondering what scale of earthquakes can be missed if they occur in just the right place, due to gaps in the observing network and the energy dropping too low by the time it reaches the nearest seismic stations.&lt;/p&gt;&#xA;&lt;p&gt;Being a novice, I have no idea about typical resolution of instruments, the density/gaps in the observing network, nor whether earthquakes have other wave features that are more coherent and consistent than the impacts of weaponry explosions.  But I figure there must be an intensity and location that would be currently undetectable?  &lt;strong&gt;So how strong of an earthquake can be missed these days?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;For simplicity's sake, lets focus on fairly shallow earthquakes (in/near the crust?), as I'm figuring depth is an additional factor... and some quite strong movements thousands of km down go undetected!?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="6298" LastEditorUserId="6298" LastEditDate="2023-11-19T07:36:52.537" LastActivityDate="2024-01-24T09:51:05.177" Title="What's the strongest earthquake we currently can miss observing on Earth?" Tags="|earthquakes|seismology|remote-sensing|earth-observation|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25743" PostTypeId="1" CreationDate="2023-11-17T15:19:57.557" Score="2" ViewCount="65" Body="&lt;p&gt;Is there a list giving an estimate of the abundance of every element of the periodic table in the Earth's Core - possibly differentiating by inner core and outer core?&lt;/p&gt;&#xA;&lt;p&gt;I am specifically interested in estimates for extremely rare trace elements.&lt;/p&gt;&#xA;" OwnerUserId="30034" OwnerDisplayName="catalyst" LastActivityDate="2023-11-19T07:41:32.193" Title="Composition of Earth's Core" Tags="|geophysics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25744" PostTypeId="1" AcceptedAnswerId="25745" CreationDate="2023-11-18T22:03:37.383" Score="6" ViewCount="5093" Body="&lt;p&gt;Given the fact that &lt;a href=&quot;https://www.epa.gov/ghgemissions/sources-greenhouse-gas-emissions&quot; rel=&quot;nofollow noreferrer&quot;&gt;industries emit about 1.5 billion metric tons of carbon dioxide&lt;/a&gt; each year just in the US, why is it still such a small part of the atmosphere's composition (0.04%)?&lt;/p&gt;&#xA;" OwnerUserId="30038" LastEditorUserId="543" LastEditDate="2023-11-22T17:46:29.400" LastActivityDate="2023-11-22T21:31:21.763" Title="Why is CO₂ abundance in the atmosphere still small?" Tags="|atmosphere|greenhouse-gases|" AnswerCount="3" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="25745" PostTypeId="2" ParentId="25744" CreationDate="2023-11-19T00:12:35.330" Score="22" Body="&lt;p&gt;The &lt;a href=&quot;https://nssdc.gsfc.nasa.gov/planetary/factsheet/earthfact.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;mass of the atmosphere&lt;/a&gt; is 5.1 × 10&lt;sup&gt;18&lt;/sup&gt; kg, which is 5.1 × 10&lt;sup&gt;15&lt;/sup&gt; t.&lt;/p&gt;&#xA;&lt;p&gt;As stated in the edited question,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;industries emits 1.5 billion metric tons of carbon dioxide each year,&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;That's 1.5 × 10&lt;sup&gt;9&lt;/sup&gt; t.&lt;/p&gt;&#xA;&lt;p&gt;The mass of Earth's atmosphere is 3,400,000 times the mass of CO&lt;sub&gt;2&lt;/sub&gt; that industries produces each year in the US.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="543" LastEditDate="2023-11-22T17:50:05.707" LastActivityDate="2023-11-22T17:50:05.707" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="25746" PostTypeId="2" ParentId="25743" CreationDate="2023-11-19T00:29:51.907" Score="4" Body="&lt;p&gt;The radius of the Earth is 6371 km. The &lt;a href=&quot;https://en.wikipedia.org/wiki/Kola_Superdeep_Borehole&quot; rel=&quot;nofollow noreferrer&quot;&gt;deepest hole drilled&lt;/a&gt; reached a depth of 12.262 km, which is a long way from the center of the Earth. We haven't even punched the crust and reached the upper mantle. Consequently, we haven't been able to directly sample the Earth's core to accurately determine its composition.&lt;/p&gt;&#xA;&lt;p&gt;Its &lt;a href=&quot;https://en.wikipedia.org/wiki/Earth%27s_inner_core#Composition&quot; rel=&quot;nofollow noreferrer&quot;&gt;composition&lt;/a&gt; is based on inference,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;There is still no direct evidence about the composition of the inner core. However, based on the relative prevalence of various chemical elements in the Solar System, the theory of planetary formation, and constraints imposed or implied by the chemistry of the rest of the Earth's volume, the inner core is believed to consist primarily of an iron–nickel alloy.&lt;/p&gt;&#xA;&lt;p&gt;At the known pressures and estimated temperatures of the core, it is predicted that pure iron could be solid, but its density would exceed the known density of the core by approximately 3%. That result implies the presence of lighter elements in the core, such as silicon, oxygen, or sulfur, in addition to the probable presence of nickel. Recent estimates (2007) allow for up to 10% nickel and 2–3% of unidentified lighter elements.&lt;/p&gt;&#xA;&lt;p&gt;... the liquid outer core contains 8–13% of oxygen, but as the iron crystallizes out to form the inner core the oxygen is mostly left in the liquid.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Subsequently, there is no list of the abundances of all the elements that exist in the Earth's core. Some of the lighter elements do not occur within the core.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="6298" LastEditDate="2023-11-19T07:41:32.193" LastActivityDate="2023-11-19T07:41:32.193" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25747" PostTypeId="1" CreationDate="2023-11-19T14:44:07.850" Score="1" ViewCount="52" Body="&lt;p&gt;When I look at radar data (in Windy for example), and I'm looking into a thunderstorm, I often see thunderbolts appearing in 'real time' on the map. How does that work ? I assume some satellites have the ability to detect them, but I wonder what is the physical process behind that.&lt;/p&gt;&#xA;" OwnerUserId="30041" LastActivityDate="2023-11-19T14:44:07.850" Title="How do we detect thunderbolts in real time?" Tags="|meteorology|satellites|thunderstorm|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25749" PostTypeId="1" CreationDate="2023-11-19T21:06:50.217" Score="2" ViewCount="32" Body="&lt;p&gt;I'm studying for an exam and I'm having a problem understanding a picture from book &amp;quot;An Introduction to Dynamic Meteorology&amp;quot; by James R. Holton (fig 6.6 in version 2004).&lt;/p&gt;&#xA;&lt;p&gt;I'm not sure if I correctly understood what are a &amp;quot;ridge&amp;quot; and a &amp;quot;trough&amp;quot; on that picture. Are those lines group of points that show min/max of geopotential at each height in an isobaric coordinate system?&lt;/p&gt;&#xA;&lt;p&gt;For example, if I draw a straight line parallel to an X axis at some height (for example 500 hPa) would points of intersections with &amp;quot;ridge&amp;quot; and &amp;quot;trough&amp;quot; lines give me points of max/min values of geopotential at that height?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/sgb87.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/sgb87.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="22324" LastEditorUserId="2470" LastEditDate="2023-11-20T04:31:04.453" LastActivityDate="2023-11-20T04:31:04.453" Title="(topic: dynamic meteorology) Problem understanding a picture from Holton version 2004" Tags="|meteorology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25750" PostTypeId="1" AcceptedAnswerId="25753" CreationDate="2023-11-20T12:05:43.613" Score="3" ViewCount="61" Body="&lt;p&gt;In the book The Great Arc, John Keay writes this about the Trigonometrical Survey of India that started in the earlier part of the 19th century:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Survey work was conducted during and immediately after the monsoon&#xA;because, regardless of the discomfort, it was only then that the dust&#xA;was laid and the heat-haze dispersed. In the interludes of bright&#xA;sunshine, the atmosphere was at its clearest. . .&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;To me, this suggested that, for the surveyors, this problem was unique to India and they might not have faced this issue in places such as England (or maybe this conclusion is wrong?)&lt;/p&gt;&#xA;&lt;p&gt;Since this was in the earlier part of the 19th century, there was no pollution due to factories or cars. The surveyors would often be away from villages and towns so probably no pollution due to human activity (cooking fires etc.,).&lt;/p&gt;&#xA;&lt;p&gt;Does this imply that the subcontinet is hazier/dustier than other parts of the globe?&lt;/p&gt;&#xA;" OwnerUserId="30050" LastActivityDate="2023-11-21T01:37:38.223" Title="Is the Indian subcontinent naturally hazier and dustier than England" Tags="|atmospheric-dust|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25751" PostTypeId="2" ParentId="25744" CreationDate="2023-11-20T15:37:03.043" Score="20" Body="&lt;p&gt;As well as the atmosphere having a lot of mass, there are many processes which remove CO&lt;sub&gt;2&lt;/sub&gt; from the atmosphere, see the wikipedia article for &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbon_cycle&quot; rel=&quot;noreferrer&quot;&gt;the carbon cycle&lt;/a&gt;. Plants sequester it as biomass, some of which ultimately ends up in the soil long-term (the rest is either released again by organic decay or fires). The ocean also absorbs a lot, which is related to the problem of ocean acidification you may have heard of.&lt;/p&gt;&#xA;&lt;p&gt;It's a delicately balanced dynamic equilibrium that we are disrupting, not a static situation. Think of it like a sink with a half blocked drain that's slowly filling up as you run the water, rather than an empty bowl you're filling up.&lt;/p&gt;&#xA;" OwnerUserId="18772" LastEditorUserId="18772" LastEditDate="2023-11-21T19:02:17.917" LastActivityDate="2023-11-21T19:02:17.917" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25753" PostTypeId="2" ParentId="25750" CreationDate="2023-11-21T01:37:38.223" Score="1" Body="&lt;p&gt;There were two sources of solid matter polluting India air during the 19&lt;sup&gt;th&lt;/sup&gt; century, that are still applicable today: farmers burning stubble and dust raised from arid regions during dry, hot windy periods.&lt;/p&gt;&#xA;&lt;p&gt;In Britain and Europe during that period, dust raised from arid regions would not have been a usual occurrence. As, happens in the contemporary period, both would have experienced occasional dust storms from the Sahara Desert.&lt;/p&gt;&#xA;&lt;p&gt;The burning of stubble would have been practiced in Britain and Europe. It is questionable whether England would have experienced hazy conditions due to this during that time due to prevailing wind conditions and the amount of stubble that would have been burned.&lt;/p&gt;&#xA;&lt;p&gt;The comment made by the British surveyors in India at the time does not suggest air pollution conditions were neither better or worse than those in Britain at the time. I read it as a comment on how conditions were in India when they needed to do a particular survey and why they chose to conduct the survey when they did. Limited visibility due to air pollution makes surveying difficult because it reduces the length of the lines of sight and result in misreading of survey targets.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-11-21T01:37:38.223" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25754" PostTypeId="1" CreationDate="2023-11-21T23:32:01.750" Score="3" ViewCount="86" Body="&lt;p&gt;Earth's atmosphere has gone through &amp;quot;dramatic&amp;quot; composition &lt;a href=&quot;https://en.wikipedia.org/wiki/Atmosphere_of_Earth#Evolution_of_Earth%27s_atmosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;changes&lt;/a&gt; over millions of years. A well-known example is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Great_Oxidation_Event&quot; rel=&quot;nofollow noreferrer&quot;&gt;Great Oxidation Event&lt;/a&gt;. Currently the atmosphere is 78% nitrogen, 21% Oxygen, 1% Argon, and 0.04% Carbon Dioxide.&lt;/p&gt;&#xA;&lt;p&gt;Atmospheric composition is changing because of human activity. Is it also changing because of natural forces? For example, have oxygen levels stabilised or will they continue to change because of oxidation cycles from life on Earth? Is volcanic activity, solar activity, or other natural factors slowly changing the atmospheric composition?&lt;/p&gt;&#xA;&lt;p&gt;CODA: The motivation of my question is the fact that we humans evolved in and adapted to the current atmospheric composition, but we might not be adapted for future compositions if over millions of years the atmosphere continues to change.&lt;/p&gt;&#xA;" OwnerUserId="13541" LastEditorUserId="13541" LastEditDate="2023-11-23T13:40:33.467" LastActivityDate="2023-11-23T23:12:42.237" Title="Is the atmospheric composition still changing naturally?" Tags="|atmosphere|paleoclimatology|great-oxidation-event|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25755" PostTypeId="1" AcceptedAnswerId="25766" CreationDate="2023-11-22T00:21:18.080" Score="4" ViewCount="178" Body="&lt;p&gt;I'm just starting out in geology and I keep reading that ionic bonds predominate among minerals. However, the majority of minerals are silicates and the silicate ion has covalent bonds, so they obviously are everywhere, too. (Not to mention carbonates, sulfates, etc.).&lt;/p&gt;&#xA;&lt;p&gt;So why do geologists think ionic bonds are dominant?&lt;/p&gt;&#xA;" OwnerUserId="30068" LastEditorUserId="2470" LastEditDate="2023-11-22T02:12:03.243" LastActivityDate="2023-12-01T12:56:42.490" Title="Why are ionic bonds considered the &quot;dominant&quot; type in minerals?" Tags="|geochemistry|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25756" PostTypeId="1" CreationDate="2023-11-22T00:39:18.687" Score="3" ViewCount="280" Body="&lt;p&gt;At 100% relative humidity, the dew point temperature is the same as the current temperature. One would probably conclude that water would start condensing on surfaces.&lt;/p&gt;&#xA;&lt;p&gt;But seems that is not always the case.&lt;/p&gt;&#xA;&lt;p&gt;This morning in Hong Kong, the RH is around 100% and temperature is around 19 degree Celsius.&lt;/p&gt;&#xA;&lt;p&gt;But the air feels really dry, and there is no condensation on surface. In fact, we have practically a clear blue sky today. Hong Kong Observatory forecast the probability of rain less than 20%.&lt;/p&gt;&#xA;&lt;p&gt;So, how do we understand this situation?&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Is it possible? Or is it simply faulty equipment for reading 100% RH?&lt;/li&gt;&#xA;&lt;li&gt;How come at dew point that water droplet is not dripping on surfaces like in spring or summer when temperature is hotter?&lt;/li&gt;&#xA;&lt;li&gt;Is there are measurement we can use to better tell the possibility of condensation, cloud, rain, and generally how wet the weather is than RH?&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="30069" LastEditorUserId="30069" LastEditDate="2023-11-23T02:02:29.600" LastActivityDate="2023-12-07T10:45:28.580" Title="At 100% relative humidity, why does the air still feels dry?" Tags="|meteorology|humidity|condensation|" AnswerCount="2" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25757" PostTypeId="1" CreationDate="2023-11-22T09:37:58.477" Score="3" ViewCount="58" Body="&lt;p&gt;I understand that low pressure systems (like hurricanes), can move across oceans since they are constantly fed by warm air from below.&lt;/p&gt;&#xA;&lt;p&gt;But what is it that enables it to move across land? Especially in winter? From where is the warm air, needed to keep it rising, coming from?&lt;/p&gt;&#xA;" OwnerUserId="29907" OwnerDisplayName="Guy" LastEditorUserId="2470" LastEditDate="2023-11-22T19:13:01.953" LastActivityDate="2023-11-22T19:15:45.910" Title="How Low pressure moves across land" Tags="|meteorology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25758" PostTypeId="2" ParentId="25757" CreationDate="2023-11-22T10:01:53.790" Score="3" Body="&lt;p&gt;&lt;sub&gt;This will be an attempt to condense a very, very complicated description of earth's atmospheric system into a simple explanation. More than likely a failure will incur&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;First you have to realize that something being &amp;quot;warm&amp;quot; is relative. It would be better to use the word &amp;quot;warmer&amp;quot;, since for convection to emerge it is enough that the air mass is warmer than its surroundings.&lt;/p&gt;&#xA;&lt;p&gt;What basically keeps weather systems evolving and on the move is the rotation of the earth and the uneven solar radiation on surfaces.&lt;/p&gt;&#xA;&lt;p&gt;The earth's rotation will &amp;quot;drag&amp;quot; along the air mass in contact with it. The amount of dragging is relative to both altitude and latitude, as they increase, the earth's rotational effect on air mass will become smaller and other effects such as &lt;a href=&quot;https://oceanservice.noaa.gov/education/tutorial_currents/media/supp_cur04b.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Coriolis effect&lt;/a&gt; will become more prevalent.&lt;/p&gt;&#xA;&lt;p&gt;Variation in the sun's radiation longitudinally creates &lt;a href=&quot;https://www.noaa.gov/jetstream/global/global-atmospheric-circulations&quot; rel=&quot;nofollow noreferrer&quot;&gt;convection currents&lt;/a&gt;, and the daily changes in surface temperature due to sun's path across the earths surface create moving convection zones.&lt;/p&gt;&#xA;" OwnerUserId="30077" OwnerDisplayName="Jpe61" LastEditorUserId="2470" LastEditDate="2023-11-22T19:15:45.910" LastActivityDate="2023-11-22T19:15:45.910" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25760" PostTypeId="2" ParentId="25744" CreationDate="2023-11-22T21:31:21.763" Score="1" Body="&lt;p&gt;&amp;quot;Small&amp;quot; is a vague and slippery term. There is now a lot &lt;em&gt;more&lt;/em&gt; CO2 in the atmosphere than there was a century ago and that change has consequences, especially to climate stability. There is a lot more human emissions - around 40 billion metric tons per year globally now - and that is causing atmospheric concentrations to rise. Those emissions are in addition to natural sources and are moderated by natural processes that absorb and recycle Carbon and overall, so far, natural processes have been taking CO2 back out of the atmosphere at rates greater all the natural CO2 flow into the atmosphere, or the human addition would be making concentrations rise faster than they are.&lt;/p&gt;&#xA;&lt;p&gt;This diagram shows The Carbon Cycle. It is a few years out of date - the amounts of fossil fuel burning and other numbers will have changed a bit but it gives a good overview of where the carbon is coming from and going to.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/st9sM.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/st9sM.jpg&quot; alt=&quot;Global Carbon Cycle&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2023-11-22T21:31:21.763" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25761" PostTypeId="1" CreationDate="2023-11-23T06:16:30.663" Score="5" ViewCount="223" Body="&lt;p&gt;I saw a recent paper where it is claimed that aftershocks can occur years, decades or centuries after the main earthquake.&lt;/p&gt;&#xA;&lt;p&gt;When seismic activity is observed, what criteria determines the classification of whether that earthquake is new or an aftershock ?&lt;/p&gt;&#xA;&lt;p&gt;Some stories about the topic:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://science.slashdot.org/story/23/11/22/165204/aftershocks-can-occur-centuries-after-original-earthquake-says-study&quot; rel=&quot;noreferrer&quot;&gt;Slashdot&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://v&quot; rel=&quot;noreferrer&quot;&gt;Guardian&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2023JB026482&quot; rel=&quot;noreferrer&quot;&gt;AGU paper&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="29749" LastEditorUserId="6298" LastEditDate="2023-11-23T15:41:08.923" LastActivityDate="2023-11-28T17:19:15.303" Title="What criteria determines whether earthquakes are classified as new or aftershocks?" Tags="|geology|geophysics|earthquakes|measurements|earth-observation|" AnswerCount="3" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25762" PostTypeId="2" ParentId="25705" CreationDate="2023-11-23T10:48:49.177" Score="0" Body="&lt;p&gt;Well, the question is not easy to answer. On the one hand, we need a data carrier that sediments reliably over several million years and thus transmits the isotope signatures of the water from the past. On the other hand, many comparative studies are needed to understand factors such as kinetic fractionation during the uptake of isotopes into the skeleton. Unfortunately, after some research I only stumbled across formainifers which fufill this criteria. In my opinion, it is also good that other animals/plants/planktons are not used so that science can concentrate on one area according to the motto simple and short.&lt;/p&gt;&#xA;&lt;p&gt;Update:&lt;/p&gt;&#xA;&lt;p&gt;Ok I now have a little more understanding of geostratigraphy using formainifers.&lt;/p&gt;&#xA;&lt;p&gt;My findings that may be important:&lt;/p&gt;&#xA;&lt;p&gt;Foraminifera have existed for about 560 million years&lt;/p&gt;&#xA;&lt;p&gt;About 2% of all animals or animal-like organisms belong to foraminifera&lt;/p&gt;&#xA;&lt;p&gt;In the North Atlantic, for example, foraminifera are responsible for 0.71 Gt yr-1 of calcite deposition&lt;/p&gt;&#xA;&lt;p&gt;In short, the high biomass or the high mass of surviving biominerals as well as a long existence time are the reason why foraminifera are essential for biostratigraphy. How @Hexenbrei has also indicated, there is a solid data base on foraminifera.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-02-21T09:19:04.447" LastActivityDate="2024-02-21T09:19:04.447" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25763" PostTypeId="1" CreationDate="2023-11-23T14:48:40.763" Score="1" ViewCount="37" Body="&lt;p&gt;Cross-posted &lt;a href=&quot;https://mattermodeling.stackexchange.com/q/11965/5&quot;&gt;on MMSE&lt;/a&gt; and  &lt;a href=&quot;https://chemistry.stackexchange.com/q/177860/27342&quot;&gt;on Chemistry&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Does anyone know where can I find measured thermal conductivity and thermal diffusivity of diatomite for different temperatures? I'm looking for the temperature dependency for temperatures higher than 300K. The upper temperature limit shall be at least 1000K, but more is better. All I have found is thermal conductivity in &amp;quot;Touloukian, Y. S., et al. &amp;quot;Thermophysical properties of matter - The TPRC data series. Volume 2. Thermal conductivity - nonmetallic solids. (1971)&amp;quot;. I'm still missing data on thermal diffusivity though, and I'd like to see more data on thermal conductivity, if available.&lt;/p&gt;&#xA;&lt;p&gt;Any help will be appreciated.&lt;/p&gt;&#xA;" OwnerUserId="30079" LastEditorUserId="18946" LastEditDate="2023-12-20T10:13:44.697" LastActivityDate="2023-12-20T10:13:44.697" Title="Thermal conductivity and diffusivity of diatomite (also known as diatomaceous earth or kieselguhr)" Tags="|temperature|thermodynamics|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25764" PostTypeId="2" ParentId="25756" CreationDate="2023-11-23T17:45:02.553" Score="5" Body="&lt;p&gt;Humans cannot directly sense humidity since we lack the &lt;a href=&quot;https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4533066/&quot; rel=&quot;noreferrer&quot;&gt;sensory neurons&lt;/a&gt; for that specific purpose.&lt;/p&gt;&#xA;&lt;p&gt;Therefore our sensation of, say, relative humidity in the air is always a combination of different sensory inputs.&lt;/p&gt;&#xA;&lt;p&gt;These inputs consist of, for example, conductive heat from the air in contact with the skin, heat radiation from direct sunlight and the pressure of small water droplets condensing on our skin.&lt;/p&gt;&#xA;&lt;p&gt;A prolonged contact with high humidity, be it vapor or liquid water, will also swell the skin some. On the other hand even the slightest wind will carry away moisture from the skin quite effectively. Our brains are calibrated to these different sensations of how our skin feels to the touch or how it feels to touch other object with different &amp;quot;skin moisture conditions&amp;quot; so to say, and we can interpret these sensations as different levels of humidity in the surroundings.&lt;/p&gt;&#xA;&lt;p&gt;The human perception of air humidity is therefore not an exact sensation but rather a computation based on several factors, making it quite unreliable.&lt;/p&gt;&#xA;" OwnerUserId="30077" LastEditorUserId="6298" LastEditDate="2023-11-24T12:15:39.927" LastActivityDate="2023-11-24T12:15:39.927" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25765" PostTypeId="2" ParentId="25754" CreationDate="2023-11-23T23:12:42.237" Score="2" Body="&lt;h2&gt;Yes the atmosphere is always in mild flux, humans are just changing it MUCH more severely than it does naturally.&lt;/h2&gt;&#xA;&lt;p&gt;the atmosphere even changes from season to season, that is the little up and down on the line in this graph. Since the amount of land receiving sunlight effects co2 and oxygen levels, which will change from winter to summer because the northern and southern hemisphere have different amounts of land.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/S66Ph.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/S66Ph.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;All kinds of factors cause small changes, volcanoes, forest fires, algae bloom, all have an impact. humans are just vastly overwhelming all those small natural fluctuations both in time and intensity.&lt;/p&gt;&#xA;&lt;p&gt;If you look at ice core data humans only have a noticeable effect right at the end, basically all the rest of that fluctuation is natural. Even things like changes in tectonics has an impact, depending on what scale you want to look at you see different factors dominating humans are just overpowering all of them. Right now we should actually be cooling due to just natural factors, yet we are warming, which makes me wonder how bad it will be when the natural factors naturally cycle back to warming as well...&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/G3ea3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G3ea3.png&quot; alt=&quot;![enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;we can even correlate things like changes due to individual volcanic eruptions.&#xA;&lt;a href=&quot;https://www.researchgate.net/figure/Volcanism-and-temperature-variability-during-the-migration-period-500-705-ce-a_fig3_279965759&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.researchgate.net/figure/Volcanism-and-temperature-variability-during-the-migration-period-500-705-ce-a_fig3_279965759&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2023-11-23T23:12:42.237" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25766" PostTypeId="2" ParentId="25755" CreationDate="2023-11-24T13:22:33.307" Score="1" Body="&lt;p&gt;First off, we should also consider the bonding between the metals and oxygen, which also occur in common igneous-rock minerals. These bonds are predominantly ionic, as the metals have lower electronegativity and less ionization energy (to their normal ionic charges) than silicon (to its &amp;quot;normal ionic&amp;quot; charge of +4).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://doi.org/10.1016/0022-3697(82)90139-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Catti[1]&lt;/a&gt; fitted the charge distribution to observed structural characteristics of the mafic mineral forsterite (&lt;span class=&quot;math-container&quot;&gt;$\ce{Mg2SiO4}$&lt;/span&gt;), identifying the following results:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{Mg}: +1.38$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{Si}: +1.44$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{O}: -1.05$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Since the theoretical ionic charges would include -2 for the electronegative oxygen atom, this represents about half the fully ionic charge separation (magnesium is 69% ionized to its noble gas core, silicon 36% showing the greater ionic character of the metal-oxygen bond). We would regard this as towards the ionic end of the bonding scale, because we would not expect 100% charge separation between individual atoms even in &amp;quot;clearly ionic&amp;quot; compounds like sodium chloride.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Reference&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Michele Catti (1982),&#xA;&amp;quot;Atomic charges in Mg2SiO4 (forsterite), fitted to thermoelastic and structural properties&amp;quot;, &lt;em&gt;Journal of Physics and Chemistry of Solids&lt;/em&gt;,&#xA;Volume 43, Issue 12, Pages 1111-1118,&#xA;ISSN 0022-3697,&#xA;&lt;a href=&quot;https://doi.org/10.1016/0022-3697(82)90139-1&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1016/0022-3697(82)90139-1&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="2470" LastEditDate="2023-11-25T05:55:14.090" LastActivityDate="2023-11-25T05:55:14.090" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25767" PostTypeId="2" ParentId="24249" CreationDate="2023-11-25T00:14:16.653" Score="1" Body="&lt;p&gt;The thing is, even if the well logs were available for a deterministic approach, the logs are not aligned with seismic. To get the initial alignment one could use synthetic trace which is done by extracting the  &lt;em&gt;statistical wavelet&lt;/em&gt; and convolving it with impedance values. Then after the alignment the deterministic approach could be used.&lt;/p&gt;&#xA;" OwnerUserId="27481" LastEditorUserId="2470" LastEditDate="2023-11-25T05:52:30.963" LastActivityDate="2023-11-25T05:52:30.963" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25769" PostTypeId="2" ParentId="25761" CreationDate="2023-11-26T19:36:00.547" Score="1" Body="&lt;p&gt;That's an interesting question. &lt;em&gt;Without&lt;/em&gt; checking literature, this is my take for an answer...&lt;/p&gt;&#xA;&lt;p&gt;A given earthquake has a defined, estimated focus and epicenter. That being said, I assume that an &amp;quot;aftershock&amp;quot; event (from an initial earthquake) is one where displacement occurs at or near that corresponding focus/epicenter from the initial earthquake - also, perhaps even with the same or similar &lt;a href=&quot;https://www.iris.edu/hq/inclass/animation/focal_mechanisms_explained&quot; rel=&quot;nofollow noreferrer&quot;&gt;focal mechanism&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="8447" LastActivityDate="2023-11-26T19:36:00.547" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25770" PostTypeId="1" CreationDate="2023-11-27T02:49:01.777" Score="0" ViewCount="5" Body="&lt;p&gt;Is anyone using SLB Omega that knows how to input the source, relation and receptor files that are not using SPS format?&lt;/p&gt;&#xA;" OwnerUserId="30087" LastEditorUserId="2470" LastEditDate="2023-11-27T05:34:25.090" LastActivityDate="2023-11-27T05:34:25.090" Title="Input of the relation, source and receptor files into SLB Omega" Tags="|geology|geophysics|seismology|oil-reserves|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25771" PostTypeId="2" ParentId="25761" CreationDate="2023-11-28T02:19:46.180" Score="1" Body="&lt;p&gt;It's always beneficial to refer to what the USGS states:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&amp;quot;Foreshock&amp;quot; and &amp;quot;aftershock&amp;quot; are relative terms.&lt;/p&gt;&#xA;&lt;p&gt;Foreshocks are earthquakes that precede larger earthquakes in the same location. An earthquake cannot be identified as a foreshock until after a larger earthquake in the same area occurs.&lt;/p&gt;&#xA;&lt;p&gt;Aftershocks are smaller earthquakes that occur in the same general area during the days to years following a larger event or &amp;quot;mainshock.&amp;quot; They occur within 1-2 fault lengths away and during the period of time before the background seismicity level has resumed. As a general rule, aftershocks represent minor readjustments along the portion of a fault that slipped at the time of the mainshock. The frequency of these aftershocks decreases with time. Historically, deep earthquakes (&amp;gt;30 km) are much less likely to be followed by aftershocks than shallow earthquakes.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.usgs.gov/faqs/foreshocks-aftershocks-whats-difference&quot; rel=&quot;nofollow noreferrer&quot;&gt;USGS&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;From this, I've learned that there are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Foreshocks, which precede larger earthquakes.&lt;/li&gt;&#xA;&lt;li&gt;Major earthquakes.&lt;/li&gt;&#xA;&lt;li&gt;Aftershocks, which are adjustments of the fault plane.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;My background was in geochemistry, not geophysics, at university, so my ability to elaborate further is limited, and this might seem like a link-only answer.&lt;/p&gt;&#xA;&lt;p&gt;I believe that the readjustment of the fault plane is the criterion for classifying an earthquake as an aftershock.&lt;/p&gt;&#xA;" OwnerDisplayName="user29779" LastEditorDisplayName="user29779" LastEditDate="2023-11-28T02:31:00.517" LastActivityDate="2023-11-28T02:31:00.517" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25772" PostTypeId="2" ParentId="25761" CreationDate="2023-11-28T17:19:15.303" Score="1" Body="&lt;p&gt;I was able to figure out the Criteria , by a little armchair research &amp;amp; inputs from user &amp;quot;nate&amp;quot; &amp;amp; from user &amp;quot;Universal_learner&amp;quot; &amp;amp; from &lt;a href=&quot;https://www.britannica.com/science/aftershock-geology&quot; rel=&quot;nofollow noreferrer&quot;&gt;Britannica&lt;/a&gt; &amp;amp; from &lt;a href=&quot;https://en.wikipedia.org/wiki/Aftershock&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wiki&lt;/a&gt; :&lt;/p&gt;&#xA;&lt;p&gt;Particularly , the Wiki Section &lt;a href=&quot;https://en.wikipedia.org/wiki/Aftershock#Effect_of_aftershocks&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Aftershock#Effect_of_aftershocks&lt;/a&gt; gave the Major Hint :&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Bigger earthquakes have more and larger aftershocks and the sequences can last for years or even longer especially when a large event occurs in a seismically quiet area; see, for example, the New Madrid Seismic Zone, where events still follow Omori's law from the main shocks of 1811–1812. An aftershock sequence is deemed to have ended when the rate of seismicity drops back to a background level; i.e., no further decay in the number of events with time can be detected.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;Thus The Main Criterion (in addition to Position &amp;amp; type &amp;amp; Etc) is whether the seismic activity has returned to normal background level.&lt;/p&gt;&#xA;&lt;p&gt;When background &amp;quot;hum&amp;quot; or &amp;quot;rumble&amp;quot; or seismic activity is higher than normal when multiple earth quake occur , then all are treated in one large &amp;quot;sequence&amp;quot; , with the &amp;quot;largest&amp;quot; called main &amp;amp; the others called foreshocks &amp;amp; aftershocks.&lt;/p&gt;&#xA;&lt;p&gt;When background seismic activity goes back to normal , then that &amp;quot;sequence&amp;quot; is deemed over.&lt;br /&gt;&#xA;That terminal event might take Days or Weeks or Months or even 200 Years.&lt;/p&gt;&#xA;&lt;p&gt;[[ I will try to added Charts &amp;amp; Images later ]]&lt;/p&gt;&#xA;&lt;p&gt;Of course , the &amp;quot;sequence&amp;quot; must occur within the same Position &amp;amp; must have same triggers , though the background seismic activity decides whether it is new &amp;quot;sequence&amp;quot; or not.&lt;/p&gt;&#xA;" OwnerUserId="29749" LastActivityDate="2023-11-28T17:19:15.303" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25773" PostTypeId="1" AcceptedAnswerId="25780" CreationDate="2023-11-28T22:47:27.257" Score="5" ViewCount="169" Body="&lt;p&gt;There is a &lt;a href=&quot;https://phys.org/news/2023-10-periodic-table-superheavy-elements-ultradense.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;story&lt;/a&gt; going around in the popular science press at the moment on that there are asteroids in the solar system that have a higher density than any known normal (atomic) material, and that these asteroids might be made of &lt;a href=&quot;https://en.wikipedia.org/wiki/Island_of_stability&quot; rel=&quot;nofollow noreferrer&quot;&gt;superheavy elements&lt;/a&gt;, which are theorized to exist but which we haven't so-far found or synthesized on earth.&lt;/p&gt;&#xA;&lt;p&gt;As far as I understand, the idea is that these superheavy elements were part of the protoplanetary disk from which the planets and asteroids formed, but on earth they would have sunk into the core and therefore would not be found in the crust. The same is theorized to have happened to other dense elements like gold. The little gold that we do find in the crust was deposited by meteorites.&lt;/p&gt;&#xA;&lt;p&gt;Assuming that superheavy elements were indeed part of the protoplanetary disk and there are asteroids and other space rocks made from it in the solar system, is there any explanation on why we haven't found any such material on earth, just like we still find small amounts of gold?&lt;/p&gt;&#xA;" OwnerUserId="30095" LastEditorUserId="30095" LastEditDate="2023-12-11T15:26:42.483" LastActivityDate="2023-12-11T15:26:42.483" Title="If superheavy elements existed in the solar system, why wouldn't we find them on earth?" Tags="|asteroids|" AnswerCount="1" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="25774" PostTypeId="1" AcceptedAnswerId="25777" CreationDate="2023-11-29T12:47:37.433" Score="2" ViewCount="74" Body="&lt;p&gt;Will it live for several million years?&lt;/p&gt;&#xA;&lt;p&gt;Is 3-4 millions years normal?&lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="6298" LastEditDate="2023-12-01T19:57:42.703" LastActivityDate="2023-12-01T19:57:42.703" Title="How long does a stratovolcano live?" Tags="|volcanology|volcanic-eruption|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25775" PostTypeId="1" CreationDate="2023-11-29T16:47:50.157" Score="4" ViewCount="82" Body="&lt;p&gt;I recently came across a science writer's page according to which clouds are liquid water. I pointed out to this author that in reality clouds are made up of a dispersion of water micro-droplets in a gas and therefore are aerosols from the physical-chemistry point of view. I received a rather abrupt answer and therefore I wonder if slightly different definitions apply in the field of meteorology than in physical-chemistry. So my question is: how is defined the state of a cloud in meteorology, is it a liquid or an aerosol?&lt;/p&gt;&#xA;&lt;p&gt;quoting Wikipedia:&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;An aerosol is a suspension of fine solid particles or liquid droplets in air or another gas&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;A liquid is a nearly incompressible fluid that conforms to the shape of its container but retains a nearly constant volume independent of pressure&amp;quot;.&lt;/p&gt;&#xA;" OwnerUserId="28210" LastActivityDate="2023-11-29T16:47:50.157" Title="Are clouds aerosol?" Tags="|meteorology|clouds|aerosol|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25776" PostTypeId="2" ParentId="25755" CreationDate="2023-11-30T12:54:48.267" Score="2" Body="&lt;p&gt;Consider pure solid Ga: all the atoms have the same value of electronegativity and hence the maximum density of electronic charge will be found exactly at the center of the Ga-Ga bond.&lt;/p&gt;&#xA;&lt;p&gt;Now consider GaAs: As has a stronger tendency to attract electrons (higher electronegativity) and so the maximum density of electronic charge will be found displaced towards As&lt;/p&gt;&#xA;&lt;p&gt;Now consider ZnSe: the difference in the electronegativity between Zn and Se is larger than that calculated in GaAs for Ga and As. Hence, the maximum density of electronic charge will be found further nearer the electronegative element, that is Se.&lt;/p&gt;&#xA;&lt;p&gt;It is clear that in this way you can move almost continuously from a purely covalent bond (for example that found in Ga, C,...) to a situation where the percentage of the ionic bond increases. Nonetheless, even in CsF, the compound with the largest ionic character, a fraction of the bonding is covalent. So ionic and covalent bonding are aspects of the same kind of bonding, namely a bonding where bonding electrons are not free as in metals.&lt;/p&gt;&#xA;&lt;p&gt;In any case, you don't have to confuse the ionic charge, which is the charge that the atoms gain by transferring electrons for the bond formation, with the formal charge, that is used to describe the external electronic configuration of the atoms.&lt;/p&gt;&#xA;" OwnerUserId="28210" LastEditorUserId="28210" LastEditDate="2023-12-01T12:56:42.490" LastActivityDate="2023-12-01T12:56:42.490" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25777" PostTypeId="2" ParentId="25774" CreationDate="2023-11-30T21:36:56.830" Score="6" Body="&lt;p&gt;I was going to write an answer based on a few known examples (see my previous comment), but a few examples are not necessarily statistically representative. So I checked good old &lt;em&gt;Encyclopedia of Volcanoes&lt;/em&gt; (Sigurdsson et al., eds, 1999) and there is exactly what you need! Chapter 41, section III, &amp;quot;Lifetimes of Composite Volcanoes&amp;quot;&lt;span class=&quot;math-container&quot;&gt;$^1$&lt;/span&gt;, &lt;a href=&quot;https://booksite.elsevier.com/9780126431407/netscape4/Contents/Chapt43_08.htm&quot; rel=&quot;noreferrer&quot;&gt;states&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The general impression from the sparse and largely poorly constrained&#xA;geochronological data on composite volcanoes is that these are&#xA;long-lived. [...] Composite volcanoes stay active for periods of up to&#xA;500 ka. Mount Adams in the Cascades dates back to ~520 ka and appears&#xA;to be typical of other large composite cones in the Cascade arc of&#xA;North America. Although the data are sparse, Mounts Baker, Rainier,&#xA;Hood, Jefferson, Mazama, and Shasta are thought to have lasted 300 ka.&#xA;[...] The observations from the Cascades are ratified from other&#xA;regions. Tongariro (New Zealand) had been active since ~250-275 ka. In&#xA;the southern volcanic zone of the Andes, composite volcanoes are&#xA;thought to have been active for periods of up to 300 ka. Volcan&#xA;Parinacota, in the central Andes, was initiated ~250 ka, after the&#xA;vent shifted slightly s outhward from its older twin cone Pomerape.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So the usual lifespan is in the order of a few hundred thousands years. From my knowledge it can be longer, a few million years, but then they are generally subdivided into multiple edifices. For example, the monts Dore massif (France) is generally divided between the Guéry stratovolcano, which was active between 3.09 and 1.46 Ma, and the Sancy stratovolcano, which was active between 1.10 and 0.28 Ma (&lt;a href=&quot;https://doi.org/10.1007/s00445-014-0798-6&quot; rel=&quot;noreferrer&quot;&gt;Nomade et al., 2014&lt;/a&gt;). A current example of this is Mount Vesuvius, which has replaced older Mount Somma at the same place.&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;&lt;sub&gt;&lt;span class=&quot;math-container&quot;&gt;$^1$&lt;/span&gt; Composite volcano is synonymous, and generally preferred, to stratovolcano.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2023-11-30T21:36:56.830" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25778" PostTypeId="1" CreationDate="2023-12-02T16:37:45.950" Score="2" ViewCount="44" Body="&lt;p&gt;I'm trying to understand Box 7.1 &amp;quot;The Energy Budget Framework: Forcing and Response&amp;quot; in the IPCC 2021 document. The link is &lt;a href=&quot;https://www.ipcc.ch/report/ar6/wg1/chapter/chapter-7/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ipcc.ch/report/ar6/wg1/chapter/chapter-7/&lt;/a&gt; .&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$N(x_{1},x_{2},\ldots,T)$&lt;/span&gt; seems to be the net radiative flux at the top of the atmosphere. So &lt;span class=&quot;math-container&quot;&gt;$N$&lt;/span&gt; is inbound &lt;span class=&quot;math-container&quot;&gt;$W m^{-2}$&lt;/span&gt; minus outbound &lt;span class=&quot;math-container&quot;&gt;$W m^{-2}$&lt;/span&gt;. N is a function of the Global Surface Air Temperature (GSAT) T and a bunch of variables &lt;span class=&quot;math-container&quot;&gt;$x_{i}$&lt;/span&gt; specifying the state of the atmosphere. So, &lt;span class=&quot;math-container&quot;&gt;$x_{1}$&lt;/span&gt; (say) could be the mole fraction of CO2.&lt;/p&gt;&#xA;&lt;p&gt;The text says Effective Radiative Forcing (ERF) &lt;span class=&quot;math-container&quot;&gt;$\Delta F$&lt;/span&gt; (units power per unit area),&#xA;&amp;quot;quantifies the change in the net TOA energy flux of the Earth system due to an imposed perturbation  that are uncoupled to any GSAT change.&amp;quot;   So, I think this means,&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\Delta F=\frac{\partial N}{\partial x_{i}}\Delta x_{i}&#xA;\end{equation}&lt;/span&gt;&#xA;summed over repeated &lt;span class=&quot;math-container&quot;&gt;$i$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;The text also explicitly defines the feedback parameter &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt; (units &lt;span class=&quot;math-container&quot;&gt;$W m^{-2} K^{-1}$&lt;/span&gt;) as,&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\alpha=\frac{\partial N}{\partial x_{i}}\frac{dx_{i}}{dT}&#xA;\end{equation}&lt;/span&gt;&#xA;Earlier in the text, the following equation was written,&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\Delta N=\Delta F +\alpha \Delta T&#xA;\end{equation}&lt;/span&gt;&#xA;Now  mathematically, &lt;span class=&quot;math-container&quot;&gt;$\Delta N$&lt;/span&gt; has to be,&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\Delta N=\frac{\partial N}{\partial x_{i}}\Delta x_{i}+\frac{\partial N}{\partial T}\Delta T&#xA;=\frac{\partial N}{\partial x_{i}}\frac{dx_{i}}{dT}\Delta T+\frac{\partial N}{\partial T}\Delta T=\alpha\Delta T+\frac{\partial N}{\partial T}\Delta T \neq\alpha\Delta T +\Delta F&#xA;\end{equation}&lt;/span&gt;&#xA;The definition in the text for the ERF &lt;span class=&quot;math-container&quot;&gt;$\Delta F$&lt;/span&gt; doesn't seem consistent. What am I failing to understand?&lt;/p&gt;&#xA;" OwnerDisplayName="user30116" LastActivityDate="2023-12-02T16:37:45.950" Title="Need help to understand definitions in Box 7.1 (Forcing and Response) in IPCC 2021" Tags="|climate-change|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25780" PostTypeId="2" ParentId="25773" CreationDate="2023-12-03T11:31:51.377" Score="7" Body="&lt;p&gt;The most likely explanation for the lack of those superheavy elements on Earth is that those elements don't exist in that asteroid. The very high mass and hence very high density estimation of 33 Polyhymnia most likely is very incorrect. Benoît Carry, the author of the article in which the estimate of ~75 g/cc was published had himself deemed that estimate to be unreliable. In that same article, Carry similarly estimated asteroid 675 Ludmilla as having a density of ~74 g/cc. Later studies arrived at a much more reasonable figure of about 4 g/cc for that asteroid.&lt;/p&gt;&#xA;&lt;p&gt;It's important to remember that the &amp;quot;island of stability&amp;quot; (or islands of stability) would be better named as islands of &lt;em&gt;relative&lt;/em&gt; stability. A half life in centuries is very stable compared to isotopes with half lives in the nanoseconds. A half life in the centuries or even in the hundreds of thousands of years is not long enough to qualify as primordial.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2023-12-06T11:51:07.110" LastActivityDate="2023-12-06T11:51:07.110" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25782" PostTypeId="1" CreationDate="2023-12-05T03:23:38.313" Score="0" ViewCount="36" Body="&lt;p&gt;&lt;img src=&quot;https://im.gurl.eu.org/file/ca3482ba56ec929fcf8b6.jpg&quot; alt=&quot;https://link.springer.com/article/10.1007/s00382-022-06369-z&quot; /&gt;&lt;br /&gt;&#xA;from &lt;a href=&quot;https://link.springer.com/article/10.1007/s00382-022-06369-z&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://link.springer.com/article/10.1007/s00382-022-06369-z&lt;/a&gt;&#xA;&lt;img src=&quot;https://im.gurl.eu.org/file/ec25f0f66bf07415d21d7.jpg&quot; alt=&quot;enter link description here&quot; /&gt;&lt;br /&gt;&#xA;from &lt;a href=&quot;https://link.springer.com/article/10.1007/s00382-022-06577-7&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://link.springer.com/article/10.1007/s00382-022-06577-7&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;These two formulas aim to calculate cloud radiative feedback by adjusted cloud radiative forcings. In formula (1), 'F' represents 'Effective Radiative Forcing (ERF)' , while in formula (2), it denotes 'instantaneous radiative forcing (IRF)'. Which definition is correct? IRF can be directly calculated, but ERF involves adjustments that cannot be obtained directly.&lt;/p&gt;&#xA;" OwnerUserId="30128" LastEditorUserId="30128" LastEditDate="2023-12-06T08:57:29.983" LastActivityDate="2023-12-06T08:57:29.983" Title="Question about calculating cloud raditiave feedback by adjusted cloud radiative forcing" Tags="|climate-change|clouds|radiative-transfer|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25783" PostTypeId="1" CreationDate="2023-12-05T16:11:55.647" Score="1" ViewCount="45" Body="&lt;p&gt;(Alguien podría decirme qué es?)&lt;/p&gt;&#xA;&lt;p&gt;Could someone tell me what it is? Zapala is in Western Argentina, east of the Andes Mountains.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/KdqWd.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;enter image description here&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/r1xYq.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/r1xYq.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;English translation via Google Translate&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="30134" LastEditorUserId="2470" LastEditDate="2023-12-06T08:09:50.530" LastActivityDate="2023-12-06T08:09:50.530" Title="(Fósil hallado en Zapala, Neuquén) Fossil found in Zapala, Neuquén, Argentina" Tags="|paleontology|fossils|identification-request|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25784" PostTypeId="1" CreationDate="2023-12-06T11:36:11.853" Score="0" ViewCount="60" Body="&lt;p&gt;My question belongs to health and environment interactions, not to climate.&lt;/p&gt;&#xA;&lt;p&gt;I recently moved in a house close to a forest. I am living there temporarily.&lt;/p&gt;&#xA;&lt;p&gt;Wit respect to where I was living before, the apartament is basically the same, 2nd floor, same exposure to sun/wind, same size, same quality of the windows, same bed, same bedroom size (ceiling as well).&lt;/p&gt;&#xA;&lt;p&gt;My work is of intellectual nature, so I work (partially) on my own schedule from home. I work often into the late night, then I go to bed.&lt;/p&gt;&#xA;&lt;p&gt;There we go: I feel that my sleep is of worse quality, that I am less productive in my evening work ... and I decided to measure the CO₂ amount in the air. It turns out that it peaks at 1500/1800 ppm in the night. So I am considering that what I feel is due to CO₂-impairment (&lt;a href=&quot;https://earthscience.stackexchange.com/q/18390/5887&quot;&gt;see this question&lt;/a&gt; for a discussion on the topic).&lt;/p&gt;&#xA;&lt;p&gt;Taking into account that this question of mine is being written under such conditions, I am still wondering if there are studies on how strong is the CO₂ night forcing effect from forests and if it is possible to have peaks in excess of 5000ppm of CO₂ in the night, because of plant respiration not being counteracted by photosynthesis.&lt;/p&gt;&#xA;" OwnerUserId="5887" LastEditorUserId="5887" LastEditDate="2023-12-06T16:21:43.290" LastActivityDate="2023-12-06T16:21:43.290" Title="CO₂ night emissions from a forest?" Tags="|co2|plant|photosynthesis|day-night|" AnswerCount="0" CommentCount="13" ContentLicense="CC BY-SA 4.0" />
  <row Id="25785" PostTypeId="2" ParentId="25756" CreationDate="2023-12-06T11:45:26.513" Score="0" Body="&lt;p&gt;We feel absolute humidity, i.e. how heavy is air.&lt;/p&gt;&#xA;&lt;p&gt;----------CORRECTION NEEDED (thanks @Jeopardytempest)&lt;/p&gt;&#xA;&lt;p&gt;Humid air is lighter than dry air. See the relevant &lt;a href=&quot;https://en.wikipedia.org/wiki/Density_of_air&quot; rel=&quot;nofollow noreferrer&quot;&gt;wikipedia page&lt;/a&gt;. With changes in temperature temperature, the difference between densities of 100%/0% RH air increases non linearly.&lt;/p&gt;&#xA;&lt;p&gt;At 20°C, the difference is a negligible 1%.&lt;/p&gt;&#xA;&lt;p&gt;At 40°C, the difference is about 5%, which is something you surely notice.&lt;/p&gt;&#xA;&lt;p&gt;When your body requires sweating, then the blockage of evo-transpiration can be noticed and it is an indirect feeling of relative humidity.&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;----------WRONG ANSWER LEFT HERE FOR HISTORICAL REASONS&#xA;How much water can be present in air is non-linear with temperature (see here for a &lt;a href=&quot;https://%20https://www.tis-gdv.de/tis_e/misc/klima-htm/&quot; rel=&quot;nofollow noreferrer&quot;&gt;table&lt;/a&gt; to have an idea about its change).&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;At 0°C and 100% relative humidity, absolute humidity is 4.8 g/m3 (negligble, since air density is ~1200 g/m3).&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;At 20°C and 100% relative humidity, absolute humidity is 17.3 g/m3 (air density is ~1200 g/m3, it starts to be ~1% more).&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;At 40°C and 100% relative humidity, absolute humidity is 51.1 g/m3 (~5% of the air density, definitely noticeable, it is like the difference between swimming in sea water and in fresh water).&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;It is 3 times more than at 20°C, even if temperature &amp;quot;just&amp;quot; doubled (actually temperatures must be compared in K, so the temperature increase of 20°C over 293-313°K is less than 10%, and water content can increase of 300%).&lt;/sub&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;sub&gt;When your body requires sweating, then the blockage of evo-transpiration can be noticed and it is an indirect feeling of relative humidity.&lt;/sub&gt;&lt;/p&gt;&#xA;" OwnerUserId="5887" LastEditorUserId="30077" LastEditDate="2023-12-07T10:45:28.580" LastActivityDate="2023-12-07T10:45:28.580" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25789" PostTypeId="2" ParentId="25702" CreationDate="2023-12-07T13:28:03.057" Score="2" Body="&lt;p&gt;This is what I have done:&#xA;First, using the parameters for LCC projection I did a coordinate transformation on the weather charts using QGIS. For this the charts needs to be georeferenced first based on lat-lon values of grid intersection. After transforming the charts in LCC to rectilinear grid I implemented &amp;quot;detectMSERFeatures&amp;quot;, a computer vision tool in MATLAB, to identify the desired pixel. The pixels have one-to-one relationship with lat-lon using which I was able to get the desired feature's coordinates.&lt;/p&gt;&#xA;" OwnerUserId="29923" LastActivityDate="2023-12-07T13:28:03.057" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25790" PostTypeId="1" AcceptedAnswerId="25791" CreationDate="2023-12-08T09:26:42.193" Score="3" ViewCount="89" Body="&lt;p&gt;I would not be surprised if the answer is the South Pole, because it is much colder and the vapor pressure drops very quickly with temperature.&lt;/p&gt;&#xA;" OwnerUserId="7416" LastEditorUserId="6298" LastEditDate="2023-12-08T10:01:43.877" LastActivityDate="2023-12-09T04:58:45.347" Title="Which is drier, the Sahara Desert or the South Pole?" Tags="|humidity|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25791" PostTypeId="2" ParentId="25790" CreationDate="2023-12-08T17:45:42.170" Score="1" Body="&lt;p&gt;This is a fun question since the Sahara and Antarctica are not points but areas, and figuring out averages for areas in these cases are difficult because measurements are scarce. That said we can consider the following:&lt;/p&gt;&#xA;&lt;p&gt;The Sahara is a desert region caused by the general circulation pattern on the earth. As such, measurements indicate less than 100 mm/y (Babaousmail et al., 2022). This number will, however, vary from year to year, and in addition it will also be highly dependent on climate variability; the Sahara during the ice ages was a wet region (Tierney et al., 2017).&lt;/p&gt;&#xA;&lt;p&gt;Antarctica is also very dry but this is because its central surface largely sits at very high elevation 2000--4000 m a.s.l. and is also very distant from the moisture source of the surrounding ocean. The central parts of Antarctica is thus classified as a desert. The accumulation of snow is on the order of a mm to cm/year (e.g. Richardson et al 1997).&lt;/p&gt;&#xA;&lt;p&gt;The problem comparing the two regions is that they differ not only in the obvious latitude but also in elevation and are subject to very different circulation patterns. Antarctica is largely isolated by both ocean circulation and wind patterns from the rest of the globe while the Sahara is part of the general and expected pattern of circulation caused by the Hadley cells. To be somewhat provocative, in some sense the driest point on Earth depends on where we place the stations measuring precipitation and indeed that true point may still be unknown.&lt;/p&gt;&#xA;&lt;p&gt;References&lt;/p&gt;&#xA;&lt;p&gt;Babaousmail, H., Hou, R., Ayugi, B., Sian, K. T. C. L. K., Ojara, M., Mumo, R., Chehbouni, A., &amp;amp; Ongoma, V. (2022). Future changes in mean and extreme precipitation over the Mediterranean and Sahara regions using bias-corrected CMIP6 models. International Journal of Climatology, 42(14), 7280–7297. &lt;a href=&quot;https://doi.org/10.1002/joc.7644&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://doi.org/10.1002/joc.7644&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Richardson, C., Aarholt, E., Hamran, S.-E., Holmlund, P., and Isaksson, E. (1997), Spatial distribution of snow in western Dronning Maud Land, East Antarctica, mapped by a ground-based snow radar, J. Geophys. Res., 102(B9), 20343–20353, doi:10.1029/97JB01441. &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/97JB01441&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/97JB01441&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Tierney, J.E., Pausata, F.S.R, deMenocal, P.B. (2017), Rainfall regimes of the Green Sahara.Sci. Adv. 3,e1601503. DOI:10.1126/sciadv.1601503&lt;/p&gt;&#xA;" OwnerUserId="81" LastEditorUserId="6298" LastEditDate="2023-12-09T04:58:45.347" LastActivityDate="2023-12-09T04:58:45.347" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25792" PostTypeId="1" CreationDate="2023-12-08T18:36:47.867" Score="1" ViewCount="23" Body="&lt;p&gt;I have data of P-wave polarity related to an earthquake. I tried to find the focal mechanism from the azimuth, takeoff angle, and P-wave polarity. I found that two packages, FOCMEC and HASHPY, are used, but I cannot get them to run properly. Is there any free software that I can use?&lt;/p&gt;&#xA;&lt;p&gt;I am also looking for article or book that can explain the whole process of finding focal mechanism in greater detail.&lt;/p&gt;&#xA;" OwnerUserId="30157" LastEditorUserId="6298" LastEditDate="2023-12-08T22:32:52.897" LastActivityDate="2023-12-08T22:32:52.897" Title="How can the focal mechanism of an earthquake be determined from P-wave polarity?" Tags="|seismology|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25793" PostTypeId="5" CreationDate="2023-12-08T23:04:30.037" Score="0" Body="&lt;p&gt;includes the relative and absolute age of a sample/fossil&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2023-12-08T23:37:19.147" LastActivityDate="2023-12-08T23:37:19.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25794" PostTypeId="4" CreationDate="2023-12-08T23:04:30.037" Score="0" Body="includes the relative and absolute age of a sample/fossil" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2023-12-08T23:37:08.827" LastActivityDate="2023-12-08T23:37:08.827" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25795" PostTypeId="5" CreationDate="2023-12-08T23:06:58.113" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2023-12-08T23:06:58.113" LastActivityDate="2023-12-08T23:06:58.113" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25796" PostTypeId="4" CreationDate="2023-12-08T23:06:58.113" Score="0" Body="Glacially covered continental mass in the Southern Hemisphere. " OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2023-12-11T12:51:04.903" LastActivityDate="2023-12-11T12:51:04.903" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25797" PostTypeId="1" CreationDate="2023-12-09T16:47:09.290" Score="1" ViewCount="86" Body="&lt;p&gt;Consider a measurement of the concentration of a gas such as ozone in Earth's atmosphere in pseudo-units of parts-per-million (ppm). What is needed to convert such a measurement to density of the gas? Do we just need to multiply by the density of air at the altitude that the measurement was taken? If so, this can be done using using the ideal gas law, at least for low altitudes. I'm not sure at higher altitudes where compressibility matters more.&lt;/p&gt;&#xA;&lt;p&gt;If is is easier, assume that this measurement is constant within a small box.&lt;/p&gt;&#xA;" OwnerUserId="30160" LastEditorUserId="543" LastEditDate="2023-12-11T04:11:02.593" LastActivityDate="2023-12-19T22:59:42.150" Title="How can gaseous abundance in ppm be converted to density?" Tags="|meteorology|atmosphere|climate|atmospheric-chemistry|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25798" PostTypeId="2" ParentId="25797" CreationDate="2023-12-10T22:16:51.720" Score="3" Body="&lt;p&gt;I think the ppm figure means mole fraction. So, if the CO2 concentration is 400ppm it means the mole fraction for this species is &lt;span class=&quot;math-container&quot;&gt;$x=400\times 10^{-6}$&lt;/span&gt;. Suppose the mole fraction of the ith species is &lt;span class=&quot;math-container&quot;&gt;$x_{i}=N_{i}/N$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$N_{i}$&lt;/span&gt; is the number of moles of the ith species and &lt;span class=&quot;math-container&quot;&gt;$N$&lt;/span&gt; is the total number of moles of the gas as a whole. Let &lt;span class=&quot;math-container&quot;&gt;$M_{i}$&lt;/span&gt; be the molar mass of the ith species. The density of the ith species is,&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\rho_{i}=\frac{M_{i}N_{i}}{V}=\frac{M_{i}N_{i}}{N}\frac{N}{V}=M_{i}x_{i}\frac{P}{RT}&#xA;\end{equation}&lt;/span&gt;&#xA;and the final replacement used the ideal gas law &lt;span class=&quot;math-container&quot;&gt;$PV=NRT$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;As an example, for CO2, the molar mass is 0.044kg/mol and the mole fraction is &lt;span class=&quot;math-container&quot;&gt;$x=400\times 10^{-6}$&lt;/span&gt;. Take the atmospheric pressure as &lt;span class=&quot;math-container&quot;&gt;$P=10^{5}$&lt;/span&gt;Pa and &lt;span class=&quot;math-container&quot;&gt;$T=300$&lt;/span&gt;K and the gas constant &lt;span class=&quot;math-container&quot;&gt;$R=8.314$&lt;/span&gt;J/mol/K so the density of CO2 is,&#xA;&lt;span class=&quot;math-container&quot;&gt;\begin{equation}&#xA;\rho=\frac{0.044\times 4\times 10^{-4}\times 10^{5}}{8.314\times 300}=7\times 10^{-4}kg/m^{3} &#xA;\end{equation}&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerDisplayName="user30116" LastEditorDisplayName="user30116" LastEditDate="2023-12-10T22:22:59.830" LastActivityDate="2023-12-10T22:22:59.830" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25799" PostTypeId="1" CreationDate="2023-12-11T08:12:48.393" Score="1" ViewCount="75" Body="&lt;p&gt;I'm not an expert in the sustainable aviation fuel field, but I have a descent understanding of science and the energy sector.&lt;/p&gt;&#xA;&lt;p&gt;I recently attended a conference where there were several presentations on Sustainable Aviation Fuels (SAF). As I absorbed the information, I started to form a opinion - that it might be cheaper and easier to sequester, deep underground, the raw materials used in the production of Sustainable Aviation Fuels (SAF), and then just continue to use kerosene to fuel jets. The process of converting those raw materials into SAF seems to be unnecessary and inefficient, if the goal is to reduce greenhouse gas emissions.&lt;/p&gt;&#xA;&lt;p&gt;I've since learned that my alternative approach is called &amp;quot;offsetting&amp;quot;. Presumably, the proponents of SAF believe that they can come up with an SAF generation processes that in some way will outperform offsetting.&lt;/p&gt;&#xA;&lt;p&gt;Is it probable that a fully mature SAF generation process will outperform offsetting? Or, should we deprioritize SAF and focus our research dollars on a more promising solutions?&lt;/p&gt;&#xA;" OwnerUserId="27098" LastActivityDate="2023-12-11T14:13:59.633" Title="Do sustainable aviation fuels make sense?" Tags="|climate|air-pollution|energy|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25800" PostTypeId="2" ParentId="25799" CreationDate="2023-12-11T13:03:34.520" Score="3" Body="&lt;p&gt;A full answer to your question could probably be book length, so I'll try to sum up the main arguments:&lt;/p&gt;&#xA;&lt;p&gt;There are a couple of options for making non-oil-based aviation fuels. One is to grow specific crops which can yield a kind of bio-oil. This requires land, and energy for the refining process. Bio-oil crops for diesel have already &lt;a href=&quot;https://www.theguardian.com/global-development/poverty-matters/2013/nov/26/burning-food-crops-biofuels-crime-humanity&quot; rel=&quot;nofollow noreferrer&quot;&gt;affected food prices&lt;/a&gt;, and pushed further rainforest deforestation as available land for food growing is shifted. Should we be reserving vast quantities of a scarce resource for plane fuel rather than food? And if there is any spare cropland around which we don't necessarily need for food, what's the opportunity cost of not planting trees on it, with much better carbon sequestration and biodiversity benefits?&lt;/p&gt;&#xA;&lt;p&gt;The other problem with biofuels is that the processing, transport, land use change and so on (everything except the burning) creates emissions. So although the premise is that by burning the crops we're just releasing CO2 already sequestered, that's not the whole picture. And processing the fuels is usually very energy intensive. For aviation in particular as well, a large chunk of emissions comes not from CO2 but from radiative forcing of high altitude emissions. So alternative fuels don't automatically fix the global warming aspect.&lt;/p&gt;&#xA;&lt;p&gt;The logic of offsets isn't strong. We need to drastically reduce emissions, fast. &amp;quot;Offsetting&amp;quot; so overall emissions level stays the same doesn't cut it. Not to mention that offsetting schemes have mainly turned out to be scams.&lt;/p&gt;&#xA;&lt;p&gt;For aviation in particular, this is all happening against a backdrop of massive inequity. Hardly anyone in the world flies, only the rich. Why should the poorest in the world (those who already cause almost no damage in emissions terms, and who have the most precarious access to food) accept the rich maintaining a massive share of cropland and energy to fund their excesses?&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;Other alternative fuels exist, e.g. hydrogen, or waste cooking oil. But for hydrogen see the massive energy usage argument (it needs energy to generate, store, transport etc.) and there's hardly any waste cooking oil around, definitely not enough to maintain anything like the level of today's flying.&lt;/p&gt;&#xA;&lt;p&gt;Flying is extremely energy-intensive. In a world in which we need to be using vast amounts of today's available energy in building renewables, why should we be making that energy sacrifice worse on something that's so inefficient and profligate?&lt;/p&gt;&#xA;" OwnerUserId="27942" LastEditorUserId="27942" LastEditDate="2023-12-11T14:13:59.633" LastActivityDate="2023-12-11T14:13:59.633" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25801" PostTypeId="1" CreationDate="2023-12-11T21:08:46.603" Score="0" ViewCount="82" Body="&lt;p&gt;I am doing a hobby project and am in search of a high quality hydrophone for less than $500. I really do not have any idea about such instruments, so I am struggling to make sense of the products on the market -- specifically in terms of how to determine which is better/worse.&lt;/p&gt;&#xA;&lt;p&gt;And most of the websites, for whatever reason, do not show prices.... e.g., &lt;a href=&quot;https://oceansonics.com/products/iclisten-sj9/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://oceansonics.com/products/iclisten-sj9/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Importantly, I'd like to be able to hook my hydrophone up to an &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/B0BYGB3WV4&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;NVidia Jetson&lt;/a&gt; for data analysis.&lt;/p&gt;&#xA;&lt;p&gt;I would really appreciate it if someone could kindly point me to some decent hydrophones that cost $500 or less, and can be interfaced with via something like an &lt;a href=&quot;https://rads.stackoverflow.com/amzn/click/com/B0BYGB3WV4&quot; rel=&quot;nofollow noreferrer&quot; rel=&quot;nofollow noreferrer&quot;&gt;NVidia Jetson&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="30169" LastActivityDate="2024-01-12T09:05:15.587" Title="High quality hydrophone for less than $500?" Tags="|oceanography|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25803" PostTypeId="1" CreationDate="2023-12-12T00:08:10.243" Score="1" ViewCount="75" Body="&lt;p&gt;I keep hearing that the models used for global ocean simulations are not actually dissipative, even though they clearly have dissipative terms and we couldn't solve them if they didn't (here, &amp;quot;solve&amp;quot; means they don't blow up numerically).  I don't find this obvious in the least, and I have not seen this mentioned or discussed in the relevant literature/textbooks (but then I have not spent the hours digging through the literature to find such an explanation, though I anticipate it would take longer to comb the literature than to take a global ocean model and figure it out directly).  The primitive equations are clearly dissipative with a finite-dimensional attractor (moreover one has to artificially inflate the diffusion coefficients to make the simulations run in the first place), so if one tries to solve these equations for a simple model, without implementing any parameterizations, it should simply be dissipative.  Numerical discretization in space definitely creates new issues, but in general such approximations &lt;em&gt;add&lt;/em&gt; spurious dissipation.  Any insight into the non-dissipativity of large-scale climate models (with the parameterizations turned off) would be greatly appreciated.&lt;/p&gt;&#xA;" OwnerUserId="30170" LastActivityDate="2023-12-20T18:39:08.137" Title="Global Ocean Models not dissipative?" Tags="|climate-models|numerical-modelling|fluid-dynamics|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25805" PostTypeId="2" ParentId="25801" CreationDate="2023-12-13T07:52:58.037" Score="0" Body="&lt;p&gt;After a bit of research I've found a hydrophone that seems to suit your requirements and is within your budget (It's approximately 210 USD)&lt;/p&gt;&#xA;&lt;p&gt;The H2D hydrophone from Aquarian Hydrophones is recommended for enthusiasts. The H2dm is compatible with Raspberry Pi and Arduino. The hydrophone has low self noise good sensitivity.&lt;/p&gt;&#xA;&lt;p&gt;Here is a buyers guide: &lt;a href=&quot;https://acousticnature.com/journal/best-hydrophone-microphones-for-field-recording#google_vignette=&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://acousticnature.com/journal/best-hydrophone-microphones-for-field-recording#google_vignette=&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="12663" LastEditorUserId="12663" LastEditDate="2023-12-13T08:11:14.677" LastActivityDate="2023-12-13T08:11:14.677" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25806" PostTypeId="1" CreationDate="2023-12-13T09:33:47.043" Score="2" ViewCount="109" Body="&lt;p&gt;I've learnt that water evaporates from the Earth's surface into the atmosphere. However, during hot/dry seasons, evaporation and transpiration occurs continuously without any sign of rainfall. What causes the absence of rainfall during dry seasons?&lt;/p&gt;&#xA;" OwnerUserId="30179" LastEditorUserId="543" LastEditDate="2023-12-14T06:17:55.153" LastActivityDate="2024-02-01T10:42:58.303" Title="What causes the absence of rainfall during dry seasons?" Tags="|atmosphere|precipitation|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25809" PostTypeId="1" CreationDate="2023-12-16T11:05:52.003" Score="3" ViewCount="39" Body="&lt;p&gt;Canada's larger lakes (minus the &amp;quot;Great Lakes&amp;quot; that it shares with the USA) sit on the edge of the Canadian Shield (&lt;a href=&quot;https://www.youtube.com/watch?v=2TmSP02zPaI&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=2TmSP02zPaI&lt;/a&gt;). On the other side of the basin, formed as a result, sits the American Cordillera which is already prime lake forming area. This plus their size and shape implies that like the Great Lakes, they have an origin beyond glaciation.&lt;/p&gt;&#xA;&lt;p&gt;Specifically, Great Slave Lake sits upon the Precambrian Great Slave Lake shear zone, so shouldn't much of it should still exist even without glaciation?&lt;/p&gt;&#xA;&lt;p&gt;Which other large lakes would still exist without glaciation, instead caused by geological features?  And how would the mentioned lakes (and any other similar Canadian lakes with origins beyond glaciation) look if Canada never glaciated? Or at the very least, what features do they show that are not the result of glaciation?.&lt;/p&gt;&#xA;" OwnerUserId="27828" LastEditorUserId="6298" LastEditDate="2023-12-17T06:49:31.777" LastActivityDate="2023-12-17T06:49:31.777" Title="What would Canada's larger lakes (Bear, Great Slave, Winnipeg, and Athabasca) look like without glaciation?" Tags="|plate-tectonics|lakes|continental-rifting|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25810" PostTypeId="1" CreationDate="2023-12-16T20:17:36.107" Score="0" ViewCount="137" Body="&lt;p&gt;How is aqua aura quartz made?&lt;/p&gt;&#xA;&lt;p&gt;Is it a transparent non color quartz transformed into a blue quarts but only on the outside or on the inside too? What happens if I break an aqua aura crystal? Can the quartz be blue before the dying process begins? Do you have a before and after photo of a quartz turned into a aqua aura?&lt;/p&gt;&#xA;" OwnerUserId="30193" LastEditorUserId="2470" LastEditDate="2023-12-16T23:35:18.363" LastActivityDate="2024-01-16T01:02:25.297" Title="Is aqua aura quartz blue inside" Tags="|minerals|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25811" PostTypeId="2" ParentId="25810" CreationDate="2023-12-16T23:37:53.733" Score="0" Body="&lt;p&gt;&lt;a href=&quot;https://geologyscience.com/gemstone/aqua-aura-quartz/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Aqua aura quartz&lt;/a&gt; does not occur naturally. It is created by vapor deposition.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;clear quartz crystals are placed in a vacuum chamber, and a combination of pure gold and other trace metals are vaporized at high temperatures. The vaporized metal bonds to the surface of the quartz crystals, creating a thin, permanent layer of metallic iridescence. The specific metal used in this process, typically gold, is what gives Aqua Aura Quartz its distinct blue or aqua color.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2023-12-16T23:37:53.733" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25812" PostTypeId="1" CreationDate="2023-12-17T13:50:13.447" Score="1" ViewCount="14" Body="&lt;p&gt;I have worked about the wave calibration in these days, and I met a problem that the significant wave height from Delft-WAVE is much lower than the observation data. I have searched for ways from the user manual and google, and found an advice to change the whitecapping coefficient Cds. However, in Delft-WAVE GUI of Windows, there is no place to change Cds. The Cds is the default data and can not be changed in Delft-WAVE.&#xA;I know that Delft-WAVE is based on SWAN, and in the independent SWAN can change Cds in the .swn file. However, I want to run DelftWAVE module together with DelftFLOW. Is there any way to change the Cds in Delft-WAVE? I will very appreciate if you can give me an advice&#xA;There is the picture from the user manual.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/VJ8Qz.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VJ8Qz.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="30201" LastActivityDate="2023-12-17T13:50:13.447" Title="How to change the whitecapping coefficient Cds in Delft-Wave" Tags="|oceanography|wind|ocean-models|coastal|wave-modeling|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25813" PostTypeId="1" CreationDate="2023-12-17T23:40:02.520" Score="2" ViewCount="34" Body="&lt;p&gt;I guess, what they looked like before Glaciation could also work as an answer.&lt;/p&gt;&#xA;&lt;p&gt;Everything I have seen on the lakes only mention their post-glacial forms even when some of them mention that they formed on rifts and shears. Do we just know that the tectonic activity wasn't sufficient to form any Lakes at at those times in the past or have I just not come across the right resources yet?.&lt;/p&gt;&#xA;" OwnerUserId="27828" LastActivityDate="2023-12-17T23:40:02.520" Title="If there was no Glaciation, what would the USA great Lakes look like?" Tags="|plate-tectonics|lakes|watershed|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25814" PostTypeId="1" AcceptedAnswerId="25821" CreationDate="2023-12-18T10:02:33.970" Score="0" ViewCount="72" Body="&lt;p&gt;Why is it that underground facilities (or underground military bases) are almost always built into hollowed out mountains? Examples of (publicly known ones anyway) are Cheyenne Mountain Complex and Mount Weather government/ military facilities. Is having a highland/mountain a prerequisite for construction of military/government facilities? Is is not possible to construct facilities beneath lower ground, plains, dessert or under cities, besides subway stations and tunnels? Say if we wanted to build NORAD bunker somewhere deep beneath San Jose population centers, is this possible discounting the fault lines and permits for now?&lt;/p&gt;&#xA;" OwnerUserId="30206" LastEditorUserId="30206" LastEditDate="2023-12-18T10:03:15.900" LastActivityDate="2023-12-19T13:17:55.387" Title="Question regarding underground man-made facilities" Tags="|earthquakes|soil-science|bedrock|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25816" PostTypeId="2" ParentId="25814" CreationDate="2023-12-18T10:20:51.343" Score="1" Body="&lt;p&gt;It is possible, but three reasons at least play in favours of remote mountain locations:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;It is easier to dig into mountains, because you can start with the excavation directly from the mountain side, instead of having a vertical huge shaft that brings your equipment at depth into the rock formation of interest: it is easier to excavate tunnel horizontally than large diameter shaft vertically (easier, not easy :) );&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;It is easier to control access and safety of a remote installation, rather than an installation build in the middle of an urban environment;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;the structure in the mountain allows for easier control of water infiltrations and air circulation.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="5887" LastEditorUserId="5887" LastEditDate="2023-12-19T13:17:55.387" LastActivityDate="2023-12-19T13:17:55.387" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25817" PostTypeId="1" CreationDate="2023-12-18T12:19:58.300" Score="16" ViewCount="7845" Body="&lt;p&gt;I left a wheelbarrow outside overnight and it rained heavily. This morning, the water in the wheelbarrow is five (5) inches deep. It's not sitting under an eave where water might have been channeled to it, but out in the back yard fully exposed to the sky. And it's sitting quite level; I'm not measuring &amp;quot;at the deep end&amp;quot;. The weather news is saying we had two (2) inches of rain. Are there local pockets of heavier rain that would explain the discrepancy, or is the wheelbarrow not an appropriate way to measure rainfall? Is there some sort of averaging involved?&lt;/p&gt;&#xA;" OwnerUserId="28321" LastEditorUserId="4849" LastEditDate="2023-12-20T10:13:25.363" LastActivityDate="2023-12-20T10:13:25.363" Title="How is rainfall measured when the news speaks of &quot;two inches of rain&quot;" Tags="|measurements|rainfall|" AnswerCount="5" CommentCount="8" ContentLicense="CC BY-SA 4.0" />
  <row Id="25819" PostTypeId="2" ParentId="25817" CreationDate="2023-12-18T16:29:32.033" Score="23" Body="&lt;p&gt;A wheelbarrow is usually considerably wider at the top than at the bottom, so the accumulated water at the bottom will likely be deeper than what actually fell.&lt;/p&gt;&#xA;&lt;p&gt;However, rainfall can also have considerable variation in space.  I often see reported rainfall totals being for the local airport or similar.  For example, if &lt;a href=&quot;https://www.weather.gov/bou/Number1September2013Floods&quot; rel=&quot;noreferrer&quot;&gt;this rainfall&lt;/a&gt; were reported for the airport (northeast of the highway intersection in the little black outline), people a short ways southwest would have gotten half again more rain.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.weather.gov/images/bou/Kleyla2013Rainfall4.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://www.weather.gov/images/bou/Kleyla2013Rainfall4.png&quot; alt=&quot;Rainfall distribution for Colorado September 2013 floods&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Averaging will depend on what's being reported.  As mentioned, it's often at the airport or similar, but you can also see area-wide averages.  Any given reporting method could still vary significantly from the precipitation at a given point unless it's measured right there.&lt;/p&gt;&#xA;" OwnerUserId="26713" LastActivityDate="2023-12-18T16:29:32.033" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25820" PostTypeId="2" ParentId="25817" CreationDate="2023-12-18T21:56:13.860" Score="20" Body="&lt;p&gt;Weather stations measure the depth of rain that falls over a small, set area by setting an open topped cylinder of precise diameter in the open at a standard height above the ground and measuring how high the water rises within it over (usually) a 24 hour period. A standard 8&amp;quot;/203mm diameter is widely used for weather station rain gauges but is not required to give accurate measurements.&lt;/p&gt;&#xA;&lt;p&gt;At its simplest the height of the water within the cylinder - which must be flat bottomed as well as the same diameter top to bottom is measured. Buckets, wheelbarrows that are wider at the open top than the bottom - or jars that are smaller at the top - are not suitable.&lt;/p&gt;&#xA;&lt;p&gt;In practice, to make it easier and for greater accuracy a separate calibrated measuring cylinder of smaller diameter is used to measure what has collected. Each mm or inch marked on the measuring cylinder is equivalent to one mm or inch in the collecting cylinder.&lt;/p&gt;&#xA;&lt;p&gt;(The use of a separate measuring cylinder - or automated measuring equipment - means the collecting container shape or size becomes irrelevant. Measurement is calibrated to the size of the opening - the top rim of brass in the example shown. Automated rain gauges are becoming more common.)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/eb45c.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/eb45c.jpg&quot; alt=&quot;Standard manual rain gauge&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="18145" LastEditDate="2023-12-20T02:21:32.230" LastActivityDate="2023-12-20T02:21:32.230" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25821" PostTypeId="2" ParentId="25814" CreationDate="2023-12-19T00:42:41.030" Score="1" Body="&lt;p&gt;This question is not about earth science. If anything, it has more to do with engineering.&lt;/p&gt;&#xA;&lt;p&gt;Strategic or critical defense or government infrastructure needs to be protected against explosive attacks, particularly nuclear attacks. A mountain offers a sizeable protective cap/roof to an underground installation. Similar levels of protection can be provided in flat ground, but the underground installation would need to be significantly deeper.&lt;/p&gt;&#xA;&lt;p&gt;Critical parts of the installation would not be established within the mountain above the level of the ground surrounding the mountain; it would be established below.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, many mountains are composed on igneous rock: rock that solidified from a molten mass. Such rock, such as basalt or dolerite (diabase), is typically stronger than sedimentary rock and can thus offer better blast protection than sedimentary rock.&lt;/p&gt;&#xA;&lt;p&gt;Also, if the installation is established igneous rock, the same strength parameters can also mean reduced geotechnical and subsequent ground support measures would be required for the underground voids that if they were established in sedimentary rock.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.popularmechanics.com/military/a32380097/norad-cheyenne-mountain-fortress/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cheyanne Mountain&lt;/a&gt; is composed of granite, and igneous rock that solidified while still underground. The NORAD installation within Cheyanne Mountain &amp;quot;was designed to ride out a nuclear attack&amp;quot;. Having been completed in 1966, when tunnel boring machines were not a consideration, it was established using drill and blast methods and consumed &lt;a href=&quot;https://en.wikipedia.org/wiki/Cheyenne_Mountain#NORAD_operations_center&quot; rel=&quot;nofollow noreferrer&quot;&gt;500 tons of explosives&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastEditorUserId="2470" LastEditDate="2023-12-19T00:55:01.427" LastActivityDate="2023-12-19T00:55:01.427" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25822" PostTypeId="2" ParentId="25817" CreationDate="2023-12-19T03:03:25.577" Score="3" Body="&lt;p&gt;It’s the depth of water in a container of any arbitrary size (more specifically, arbitrary area of ground it covers¹, the height has to be enough to measure the volume of rain that fell) with a perfectly flat bottom and perfectly vertical sides, collected over the course of the entire period of rainfall.&lt;/p&gt;&#xA;&lt;p&gt;This is a proxy for the &lt;em&gt;volume&lt;/em&gt; of water that fell, but is particularly useful because it’s invariant of the total area that the water fell over¹ and can thus be easily used to calculate the volume for any given area of interest (because you can just multiply it by the area, instead of having to know the size of the measurement container and rely on ratios like you would if you just used the volume). This ability to use quick math to figure out the volume for a given area of ground is &lt;em&gt;really&lt;/em&gt; useful because it lets you more quickly calculate:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;How much the level of a lake is likely to rise as a result of runoff from the rainfall.&lt;/li&gt;&#xA;&lt;li&gt;How much the flow rate of a river or stream is likely to change given the rainfall (this is &lt;em&gt;super&lt;/em&gt; important for ships navigating the river).&lt;/li&gt;&#xA;&lt;li&gt;How much water needs to be let through a dam to maintain a constant reservoir depth given the rainfall.&lt;/li&gt;&#xA;&lt;li&gt;How much water needs to be used when irrigating a field to ensure the crops are not over or under watered.&lt;/li&gt;&#xA;&lt;li&gt;How likely it is that ponding (buildup of standing water in areas with poor drainage) will occur in a given area.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;em&gt;But&lt;/em&gt;, for such measurements to be accurate, the container used for measuring &lt;em&gt;must&lt;/em&gt; be designed to actually make the measurements. This means that the bottom must be flat &lt;em&gt;and&lt;/em&gt; level, and that the sides must be perfectly vertical and perfectly parallel to each other. A wheelbarrow almost never meets those requirements.&lt;/p&gt;&#xA;&lt;p&gt;Additionally, these measurements are almost always taken at some central location for the region being covered. Quite often it’s based on the nearest airport, seaport, or military installation as they typically have very accurate weather stations. Otherwise, it may be some government operated weather station in the region, or possibly a station operated by whatever entity is providing the reporting. If you’re more than a few kilometers from the measurement site, you’re actually reasonably likely to see different numbers².&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;1: I mentioned above that the measurement container can cover any area, and that the depth is invariant of the total area covered. This may seem unintuitive, but it’s actually a logical side-effect of the random nature of precipitation when observing at the scale of individual raindrops or snowflakes. If you have a infinitesimally small point, the probability that it gets hit by a raindrop in a rainstorm follows a (roughly) uniform distribution dependent on the rate of rainfall (unless there are objects nearby that might obstruct the flow, in which case their positions together with the wind direction and speed also influence the probability). Because of the law of large numbers, this means that any two arbitrary points near each other will see roughly the same number of raindrops hit them in a rainstorm, provided enough total raindrops fall proportionate to the area the storm covers (which almost always happens). This same effect is why the ground eventually ends up uniformly wet during a rainstorm no matter the rate of rainfall.&lt;/p&gt;&#xA;&lt;p&gt;2: In contrast to the point above about small-scale uniformity of precipitation, when measuring at large scales there’s quite a bit of variance (otherwise meteorology would be a much simpler science with far more accurate predictions), and the possible variance increases proportionate to the distance between the measurement sites. What this means is that the further away you are from the site the data you’re seeing is being measured at, the more likely it is that you will see different measurements locally.&lt;/p&gt;&#xA;" OwnerUserId="11498" LastEditorUserId="11498" LastEditDate="2023-12-19T03:11:35.113" LastActivityDate="2023-12-19T03:11:35.113" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25823" PostTypeId="2" ParentId="25817" CreationDate="2023-12-19T04:09:36.630" Score="6" Body="&lt;p&gt;Properly designed rain gauges can give accurate results for a given location or point in space, but the problem is that it's hard to have enough of them packed densely enough in an area to give the level of detail that you might see in maps on news stations or weather websites. Models and extrapolation can fill in the gaps to a degree, but there could be a lot of error with it.&lt;/p&gt;&#xA;&lt;p&gt;On the other hand, Doppler radar (a remote sensing tool) can measure the type and intensity of precipitation at various altitudes across an area with a radius of 100+ miles. By &amp;quot;scanning&amp;quot; periodically (it might miss very short bursts of precipitation!), this data can give a pretty good idea of what the accumulation was to a pretty fine level of spatial detail. It's the data used to create those animated maps showing the progress of a storm you might see on news channels or weather websites. Ground stations/rain gauges are then used to calibrate/verify the Doppler data; you don't need many of them for this purpose.&lt;/p&gt;&#xA;&lt;p&gt;As others mentioned, a wheelbarrow will likely overestimate how much rain accumulates. But also, the models that use the Doppler data to create precipitation accumulation estimates won't be 100% perfect; averaged across a large area (or time), they're probably really good, but as you start to zoom in towards a small enough area or point, you could very well see some deviation (variance) from the true amount.&lt;/p&gt;&#xA;&lt;p&gt;Here are a few links related to the topic of weather radar and precipitation accumulation (I'm not an expert by any means):&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Weather_radar#Accumulations&quot; rel=&quot;noreferrer&quot;&gt;(Wikipedia) Weather Radar: Accumulations&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Rain#Measurement&quot; rel=&quot;noreferrer&quot;&gt;(Wikipedia) Rain: Measurement&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.weather.gov/iwx/wsr_88d&quot; rel=&quot;noreferrer&quot;&gt;National Weather Service (United States): About our WSR 88-D Radar&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="30213" LastActivityDate="2023-12-19T04:09:36.630" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25824" PostTypeId="1" CreationDate="2023-12-19T06:30:03.833" Score="3" ViewCount="94" Body="&lt;p&gt;Shooting Stars &amp;amp; Comets have tails.&lt;/p&gt;&#xA;&lt;p&gt;Here is Example &lt;a href=&quot;https://en.wikipedia.org/wiki/Comet_tail&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wiki&lt;/a&gt; Image showing &lt;a href=&quot;https://en.wikipedia.org/wiki/Comet_tail#/media/File:Cometorbit01.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Comet with 2 tails&lt;/a&gt; :&lt;br /&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/tAXkc.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tAXkc.png&quot; alt=&quot;2 tails&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;With the Earth revolving around the Sun , is there some [invisible] &amp;quot;tail&amp;quot; like Comets have ?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;It might be invisible to earthlings. It might be outside of visible spectrum.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;It might be visible in heat or infrared or ultraviolet Image techniques , when visualized or recorded from Moon or Mars ?&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="29749" LastActivityDate="2023-12-20T16:23:38.877" Title="With the Earth revolving around the Sun , is there some [invisible] &quot;tail&quot; like Shooting Stars &amp; Comets have?" Tags="|atmosphere|geophysics|visualization|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25825" PostTypeId="2" ParentId="25817" CreationDate="2023-12-19T08:33:40.837" Score="8" Body="&lt;p&gt;In addition to what others have mentioned, sometimes measurements are simply wrong, in particular where measurements are automated.&lt;/p&gt;&#xA;&lt;p&gt;Some weeks ago, two weather stations in Germany reported over 60 mm of rain, when all the others nearby reported zero, radar reported zero, model reported zero, and satellite imagery was not consistent with precipitation.  What was going on?  You would think that automatic rainfall measurements shouldn't be too hard?  Those were automated weather stations with automated rain gauges.  During those erroneous measurements, there was a snowpack that was melting.  Most likely, rather than measuring rainfall, those gauges had been measuring snowmelt and reporting it as rain.  Since there's nobody present at weather stations in Germany any more, this will remain a hypothesis and it's up to the data users to filter out measurements that are clearly wrong.&lt;/p&gt;&#xA;&lt;p&gt;There are many other things that can go wrong with automated weather stations, but they satisfy politicians who want to reduce public spending, so...&lt;/p&gt;&#xA;" OwnerUserId="6" LastEditorUserId="6" LastEditDate="2023-12-19T08:44:59.083" LastActivityDate="2023-12-19T08:44:59.083" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25827" PostTypeId="1" CreationDate="2023-12-19T14:26:05.990" Score="1" ViewCount="32" Body="&lt;p&gt;I'm moving this question from Worldbuilding StackExchange (&lt;a href=&quot;https://worldbuilding.stackexchange.com/questions/252919/wind-patterns-on-a-tidally-locked-planets-contradict-my-logic-looking-for-corre&quot;&gt;Link&lt;/a&gt;). I know it's not strictly about Earth, but I'm hoping it will still be accepted here since it's related to meteorology. Here we go:&lt;/p&gt;&#xA;&lt;hr /&gt;&#xA;&lt;p&gt;My take on the wind patterns on a tidally locked planet (TDL) does not lead to the information given in papers and videos. Please tell me where I went wrong.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;My take:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;On a TLP, the sub-solar point is a region of low air pressure (due to its high temperature), while the night side has relative higher air pressure. Wind flows from high to low air pressure, resulting in a wind pattern as depicted below (ground level).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/3NMk3.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/3NMk3.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Additionally, the coriolis effect leads to (ground level) winds to the west, similar to earth (earth has three cells per hemisphere, but since this planet rotates slower and for simplicity, it has only one cell per hemisphere - also, I'm assuming the same direction of rotation as earth); see below.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dHJGe.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dHJGe.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;That would result in an overall pattern like this:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MUAZw.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MUAZw.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;H O W E V E R,&lt;/strong&gt;&#xA;this is not consistent with information I found online.&lt;/p&gt;&#xA;&lt;p&gt;Most prominent, there is &lt;a href=&quot;https://www.pnas.org/doi/full/10.1073/pnas.1315215111&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt; which looks into ocean currents, but since they are influenced by wind, they seem contrary to the logic above.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6rSEB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6rSEB.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Furthermore, &lt;a href=&quot;https://www.youtube.com/watch?v=LifRswfCxFU&quot; rel=&quot;nofollow noreferrer&quot;&gt;this video&lt;/a&gt; explains that the situation is as depicted below and thus coherent with what the research paper suggests.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fN2nn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fN2nn.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Please help me figure out why my understanding of wind patterns does not match the results of the research paper and the information in the video. Thanks!&lt;/strong&gt;&lt;/p&gt;&#xA;" OwnerUserId="30216" LastEditorUserId="30216" LastEditDate="2023-12-19T17:10:03.203" LastActivityDate="2023-12-19T17:10:03.203" Title="Wind patterns on a tidally locked planet (one side always faces the sun)" Tags="|wind|planetary-science|world-building|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25828" PostTypeId="2" ParentId="25824" CreationDate="2023-12-19T15:29:15.300" Score="2" Body="&lt;p&gt;&lt;strong&gt;(1) Strangely , Earth has a Dust tail though it is not similar to the Comet type !&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;A Comet will have tails made of Matter coming out of the Comet itself.&lt;br /&gt;&#xA;Earth has a tail which not made of Dusty Matter coming out of the Earth , rather it is Matter &amp;quot;floating&amp;quot; in the Solar System which is getting swirled or rearranged by the Earth.&lt;/p&gt;&#xA;&lt;p&gt;Earth tail is not visible to naked eye :&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;&amp;quot;Earth has a dust tail not because the planet itself is particularly dusty, but rather because the whole solar system is. Interplanetary space is littered with dusty fragments of comets and colliding asteroids. When Earth orbits through this dusty environment, a tail forms in the rear, akin to swaths of fallen leaves swirling up behind a streetsweeper.&amp;quot;&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://phys.org/news/2010-11-earth-tail-alien-planets.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://phys.org/news/2010-11-earth-tail-alien-planets.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;(2) Stranger Cases are Moon &amp;amp; Mercury which have the Comet type of tails !&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Moon tail is not visible to naked eye :&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/YyjG4.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/YyjG4.png&quot; alt=&quot;MOON&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.wral.com/story/mercury-s-tail/20260519/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.wral.com/story/mercury-s-tail/20260519/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Mercury tail is somewhat visible to naked eye :&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/GHtuT.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/GHtuT.png&quot; alt=&quot;MERCURY&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencealert.com/the-tail-of-mercury&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencealert.com/the-tail-of-mercury&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29749" LastActivityDate="2023-12-19T15:29:15.300" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25829" PostTypeId="2" ParentId="25797" CreationDate="2023-12-19T16:27:49.633" Score="0" Body="&lt;p&gt;The ppm designation means parts in mass per million parts in total mass.&lt;/p&gt;&#xA;&lt;p&gt;Consider component A in a gas mixture of A + B. Assume the gas is ideal (it is at high enough temperature or low enough pressure such that non-ideal effects are insignificant). Define molar masses &lt;span class=&quot;math-container&quot;&gt;$M_A$&lt;/span&gt;, &lt;span class=&quot;math-container&quot;&gt;$M_B$&lt;/span&gt;, and &lt;span class=&quot;math-container&quot;&gt;$M_G$&lt;/span&gt; (for the total gas). Under these conditions, 1 ppm A in the gas means by definition 1 mg A per 1 kg gas total. The molar mass of an ideal gas mixture is obtained by the mole fraction of A &lt;span class=&quot;math-container&quot;&gt;$y_A$&lt;/span&gt; as&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ M_G = y_A\ M_A + (1 - y_A)\ M_B $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Conversion of any &lt;span class=&quot;math-container&quot;&gt;$ppm$&lt;/span&gt; to moles A per total moles is&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$y_A = ppm\ \left(\frac{10^{-3}}{10^3}\right)\left(\frac{M_G}{M_A}\right)$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;leading to&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$M_G = \frac{M_B}{1 - ppm\ 10^{-6}\ (M_B - M_A)} \approx M_B$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The density of an ideal gas depends &lt;span class=&quot;math-container&quot;&gt;$\rho_G^\star$&lt;/span&gt; depends only on pressure, temperature, and molar mass as&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\rho_G^\star = \frac{p\ M_G}{RT}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;By example, for 2 ppm NO&lt;span class=&quot;math-container&quot;&gt;$_2$&lt;/span&gt; in air, where &lt;span class=&quot;math-container&quot;&gt;$M_{air} \approx 28$&lt;/span&gt; g/mol and &lt;span class=&quot;math-container&quot;&gt;$M_{NO2} \approx 46$&lt;/span&gt; g/mol.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$M_G = \frac{46}{1 - 2\times 10^{-6}(46 - 28)} = 46.0016... $$&lt;/span&gt;&#xA;&lt;span class=&quot;math-container&quot;&gt;$$ y_{NO2} = 2\times 10^{-6}\ \frac{46.0016...}{46} = 2.00007.. \times 10^{-6} $$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The exact conversion &lt;span class=&quot;math-container&quot;&gt;$y = ppm \times 10^{-6}$&lt;/span&gt; is approached in an ideal gas at low ppm and when no significant difference occurs between the molar masses of the added component and the gas to which the component is added.&lt;/p&gt;&#xA;" OwnerUserId="13534" LastEditorUserId="13534" LastEditDate="2023-12-19T22:59:42.150" LastActivityDate="2023-12-19T22:59:42.150" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25830" PostTypeId="1" CreationDate="2023-12-20T03:59:22.077" Score="0" ViewCount="45" Body="&lt;p&gt;&lt;a href=&quot;https://youtu.be/F0tmu-zaXig?t=81&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://youtu.be/F0tmu-zaXig?t=81&lt;/a&gt;&lt;br/&gt;&lt;a href=&quot;https://youtu.be/m3okcIdkLjk?t=452&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://youtu.be/m3okcIdkLjk?t=452&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;These lava flows have cooler, solidified lava in the center, and hotter, molten lava on their flanks, pretty consistently across every stream of the flow. However, it seems to me like the opposite should occur, for the same reason lava cools from the outside in. The outside edge of the flow is in contact with the cooler surrounding rock, so it should cool first. Does this have anything to do with the faster speed of the lava in the center? I can't find anything about the relative cooling of different locations of lava flows online.&lt;/p&gt;&#xA;" OwnerUserId="30220" LastActivityDate="2023-12-20T03:59:22.077" Title="Why do lava flows solidify faster in the center rather than the margins?" Tags="|volcanology|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25831" PostTypeId="2" ParentId="25824" CreationDate="2023-12-20T16:23:38.877" Score="3" Body="&lt;p&gt;A different take to the dust tail answer - Earth has a very well known &amp;quot;invisible tail&amp;quot;: the &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnetosphere#Structure&quot; rel=&quot;nofollow noreferrer&quot;&gt;magnetotail&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Earth's internal magnetic field compresses ahead of the Earth in its travel around the Sun due to interaction with the solar wind, and is drawn out into a long tail behind.&lt;/p&gt;&#xA;&lt;p&gt;This kind of structure is not unique to Earth.&lt;/p&gt;&#xA;" OwnerUserId="14123" LastActivityDate="2023-12-20T16:23:38.877" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25833" PostTypeId="1" CreationDate="2023-12-21T17:53:33.857" Score="3" ViewCount="56" Body="&lt;p&gt;From &lt;a href=&quot;https://futurism.com/the-byte/scientists-simulated-runaway-greenhouse-effect&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; article:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;the team from the University of Geneva (UNIGE) and the French National Centre for Scientific Research (CNRS) studied what would happen if the greenhouse effect were trapped inside the Earth's atmosphere as if under an emergency thermal blanket.&lt;/p&gt;&#xA;&lt;p&gt;If the effect were to rise too much, the amount of water vapor from evaporating oceans could be lethal.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;There is a critical threshold for this amount of water vapor, beyond which the planet cannot cool down anymore,&amp;quot; said main author and UNIGE postdoctoral researcher Guillaume Chaverot in the statement. &amp;quot;From there, everything gets carried away until the oceans end up getting fully evaporated and the temperature reaches several hundred degrees.&amp;quot;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The Earth was hotter than this in the past, so water vapour in the atmosphere would have been an effect in place then, right?&lt;/p&gt;&#xA;&lt;p&gt;How did the Earth previously cool down from these levels?&lt;/p&gt;&#xA;" OwnerUserId="770" LastActivityDate="2023-12-21T17:53:33.857" Title="How did the Earth cool from a temperature of hundreds-of-degrees, if runaway greenhouse effects also happen?" Tags="|atmosphere|climate|temperature|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25834" PostTypeId="1" CreationDate="2023-12-22T00:55:23.423" Score="1" ViewCount="69" Body="&lt;p&gt;There is an idyllic verdant valley where I live, full of mountains and hills. Most mountains are covered by vegetation, but some have flat steppe-like tops where people have small farms and homesteads. There is this particular mountain that has a farm on top that is for sale; even though the foot of the mountain is full of trees and bushes, when I get closer to the edge on top I can see there are rocky parts which the current owner told me was basalt. I can also see random rocky spots engulfed by grass and flowers on top; actually such spots are scattered across the farm. I wonder if I could hire a geologist to inspect the internal part of the mountain. Can a geologist tell me how much of it is made of basalt and how much of it is just dirt? How about the depth of such layers? Does such an examination exist? If so, how does it work?&lt;/p&gt;&#xA;&lt;p&gt;Thanks in advance.&lt;/p&gt;&#xA;" OwnerUserId="30230" LastEditorUserId="30230" LastEditDate="2023-12-22T00:57:46.747" LastActivityDate="2023-12-22T00:57:46.747" Title="How do geologists examine mountains and hills inwardly?" Tags="|geology|mountains|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25835" PostTypeId="1" CreationDate="2023-12-22T10:03:49.537" Score="0" ViewCount="38" Body="&lt;p&gt;Specifically these maps.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://imgur.com/a/Pvpm2Zy#dpWSjah&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://imgur.com/a/Pvpm2Zy#dpWSjah&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The image and mapping apps I have can't do want I want with the techniques I know, on the map like this.&lt;/p&gt;&#xA;&lt;p&gt;But If I could convert it to equirectangular, it should work but I don't know how to do that. I was told to try in G.projector but it has no settings for Polar projection and the stuff I have tried to try and brute force a polar projection, don't work (set half of the map to -70ishN and 0S and 90 - 180 east to west) so any program that I can just input polar projection directly into? and how to do it?&lt;/p&gt;&#xA;" OwnerUserId="27828" LastActivityDate="2023-12-22T10:03:49.537" Title="How to I change polar projection to equirectangular?" Tags="|mapping|interpolation|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25837" PostTypeId="1" CreationDate="2023-12-22T16:29:11.240" Score="2" ViewCount="59" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Argentobaumhauerite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Argentobaumhauerite's Wikipedia page&lt;/a&gt; lists its chemical formula as &lt;span class=&quot;math-container&quot;&gt;$\require{mhchem}\ce{Ag_{1.5}Pb_{22}As_{33.5}S_{72}}$&lt;/span&gt;. Is there a reason this chemical formula is not represented as whole-number ratios of each element?&lt;/p&gt;&#xA;" OwnerUserId="30236" LastEditorUserId="21346" LastEditDate="2023-12-27T01:39:28.473" LastActivityDate="2023-12-27T01:39:28.473" Title="Why does Argentobaumhauerite have decimals in its chemical formula?" Tags="|mineralogy|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25838" PostTypeId="2" ParentId="19789" CreationDate="2023-12-22T17:55:14.893" Score="0" Body="&lt;p&gt;Actually magnesium has lower temperature of melting compared&#xA;to aluminium (by about 10 degrees Celsius), which means that in the lower layers of the earth where aluminium particles aren't melting magnesium particles would keep dripping down. Aluminium also has higher electronegativity, which means that aluminium forms stronger bonds. Finally, the granular convection (the Brazil nut effect) may add to this, forcing bigger lumps with aluminium to roll over up to the surface following every earthquake.&lt;/p&gt;&#xA;" OwnerUserId="30167" LastEditorUserId="2470" LastEditDate="2023-12-23T03:49:09.993" LastActivityDate="2023-12-23T03:49:09.993" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25839" PostTypeId="1" CreationDate="2023-12-22T19:52:29.820" Score="2" ViewCount="88" Body="&lt;p&gt;Are there any formulas to predict population density of a geography based on known geographic factors like water, food etc. in the vicinity. Either for humans or any living organisms.&lt;/p&gt;&#xA;" OwnerUserId="30237" LastActivityDate="2024-01-14T21:34:31.757" Title="Population density formulas" Tags="|geography|" AnswerCount="3" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25840" PostTypeId="1" AcceptedAnswerId="25843" CreationDate="2023-12-22T20:46:19.633" Score="2" ViewCount="205" Body="&lt;p&gt;I'll be in Iceland in a few weeks and would love to see glowing red hot lava, however, the recent &lt;a href=&quot;https://en.wikipedia.org/wiki/2023_Sundhn%C3%BAkur_eruption&quot; rel=&quot;nofollow noreferrer&quot;&gt;Sundhnúkur eruption&lt;/a&gt; just ended, after erupting for three days. So no new lava is being pumped out, I guess, but I imagine it'll take the lava that's already come out some time to cool.&lt;/p&gt;&#xA;&lt;p&gt;My question is...  how long will it take for the lava to cool such that it's not glowing red?&lt;/p&gt;&#xA;" OwnerUserId="3157" LastEditorUserId="3157" LastEditDate="2023-12-23T00:28:45.370" LastActivityDate="2023-12-23T21:01:30.307" Title="How long will red hot lava from the Sundhnúkur eruption in Iceland be visible?" Tags="|volcanology|volcanic-hazard|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25841" PostTypeId="1" CreationDate="2023-12-23T01:21:06.150" Score="0" ViewCount="28" Body="&lt;p&gt;I have estimated the emissions (NOx, CO and HC) from a certain route, hence this is a list with emissions in grams per minute. Now I want to give some idea on the climate impact, so use the thesis from Emily Schwartz Dallara (2011) with the title &amp;quot;Aircraft Design for Reduced Climate Impact&amp;quot;, chapter 5.&lt;/p&gt;&#xA;&lt;p&gt;I want to use the following formulas:&lt;/p&gt;&#xA;&lt;p&gt;CH4 and O3L&#xA;&lt;a href=&quot;https://i.stack.imgur.com/Giqxm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Giqxm.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;H2O and O3S&#xA;&lt;a href=&quot;https://i.stack.imgur.com/vdXZn.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vdXZn.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Both formulas require the forcing factor, which is defined as:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/BiDXB.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BiDXB.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here I have my problem: I need to know the RF of CH4, O3L and O3S (for this forcing factor) but I have no clue how to determine this. I cannot find it in the thesis either.&lt;/p&gt;&#xA;&lt;p&gt;Can someone help me with obtaining this information? Again: I have the NOx, CO and HC emissions with the corresponding altitudes.&lt;/p&gt;&#xA;&lt;p&gt;The thesis can be found here:&#xA;&lt;a href=&quot;https://stacks.stanford.edu/file/druid:yf499mg3300/thesis_online_final-augmented.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://stacks.stanford.edu/file/druid:yf499mg3300/thesis_online_final-augmented.pdf&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="30239" LastActivityDate="2023-12-23T01:21:06.150" Title="Calculating the forcing factor for CH4, O3L and O3S" Tags="|climate|climate-models|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25843" PostTypeId="2" ParentId="25840" CreationDate="2023-12-23T21:01:30.307" Score="3" Body="&lt;p&gt;I have experienced a similar situation two years ago. I visited the site of the 2021 Fagradalsfjall eruption on November 18, 2021, exactly two months after the last emission of lava (and one month before the Icelandic Met Office declared the eruption officially over on December 18). We walked on top of the solidified crust of the lava pond to reach the main vent (don't do it, see below). There were some fissures in the crust, like this one, about 20 cm wide:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/0HeWhl.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0HeWhl.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;And if you looked inside the fissure, you could actually see some red glowing lava at the bottom, maybe 3 meters deep:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/g2FQ7l.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/g2FQ7l.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Nothing impressive, and maybe not what you had in mind, but it definitely qualifies as &amp;quot;red hot lava&amp;quot;, two months after the magma supply had ended. That being said, here are some thoughts about your trip plans:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;The eruption may be over, but the area is still closed for the time being. Here is the current hazard map, valid until December 29 (check for updates to see how the situation evolve). &lt;a href=&quot;https://i.stack.imgur.com/SkvCPl.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/SkvCPl.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Compared to other countries, Icelanders usually have very relaxed&#xA;rules regarding access to eruption sites (the freedom to access&#xA;private lands is a cultural thing called &lt;em&gt;almannaréttur&lt;/em&gt; and is even&#xA;written in law). So if the access is forbidden, it means Iceland&#xA;authorities have very good reasons to do it.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;Indeed, &lt;a href=&quot;https://en.vedur.is/about-imo/news/a-seismic-swarm-started-north-of-grindavik-last-night&quot; rel=&quot;nofollow noreferrer&quot;&gt;there is still ground inflation measured in the area&lt;/a&gt;, below the Svartsengi geothermal plant. It means that magma accumulation has resumed and another eruption is already on its way, although it could take weeks or months. It could be during your stay if you're lucky—and if access is allowed...&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;In any case, if you do manage to reach the last eruption site, &lt;strong&gt;don't walk on the lava flow crust in the hope to see some active lava&lt;/strong&gt;. I did it with a group of visiting volcanologists, guided by local volcanologists who had been in the field every day for six months. They knew the site very well and we just followed their tracks. It can remain dangerous for months. I hope that you'll get to see this wonder of nature, but don't risk your life for it!&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2023-12-23T21:01:30.307" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25846" PostTypeId="2" ParentId="25839" CreationDate="2023-12-29T21:27:15.093" Score="0" Body="&lt;p&gt;Population density is equal to the total population divided by the area it takes up.  The area would likely be held constant when calculating change in population density, so I think a population formula would be all you need.  That being said, I don't think a single formula would be sufficient.  Instead, you would need several formulas that relate population factors and a model that can test various assumptions.  At a minimum, you need birth rates and death rates, but those should probably be made dynamic and based on other factors.  You could use the &amp;quot;&lt;a href=&quot;https://serc.carleton.edu/NAGTWorkshops/complexsystems/stella.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stella&lt;/a&gt;&amp;quot; program to build such a model.  There are trainings and examples available &lt;a href=&quot;https://www.gaininginsight.org/learn-do/stella-online-population-modeling&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="543" LastActivityDate="2023-12-29T21:27:15.093" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25848" PostTypeId="1" AcceptedAnswerId="25850" CreationDate="2024-01-03T22:29:27.660" Score="5" ViewCount="97" Body="&lt;p&gt;A spring tide is an unusually high tide that ooccurs when the sun, earth, and moon are colinear. I understand why this would be the case when the earth is on the far side of the sun and moon. The cumulative gravitational effect of the sun and moon are additive as both are acting on the earth in the same direction. But spring tides are also deemed to occur when the earth lies in between the moon and sun. In this configuration, I would expect the gravitational attraction of the sun to be diminished by the moon since they are acting on the earth in opposite directions. So the tides should be the lowest, but they are not. Can someone explain this?&lt;/p&gt;&#xA;" OwnerUserId="30299" OwnerDisplayName="aquagremlin" LastActivityDate="2024-01-04T13:39:54.440" Title="Difference between two types of spring tides that occur every month" Tags="|tides|" AnswerCount="2" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25849" PostTypeId="2" ParentId="25848" CreationDate="2024-01-04T09:28:47.290" Score="-1" Body="&lt;p&gt;To slightly correct your definition of a spring tide, it is not one that is especially high, but one that has the biggest range between low and high tide (as opposed to a neap tide, which has the smallest range between low and high tide).&lt;/p&gt;&#xA;&lt;p&gt;As per &lt;a href=&quot;https://ntslf.org/about-tides/tides&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;, spring tides occur after every full and every new moon (so, twice per lunar cycle, or roughly twice per calendar month).&lt;/p&gt;&#xA;&lt;p&gt;In the case of your latter example, the low tide is lower than normal even though the high tide is not as high as in your first example. Hence, the difference betweeen the high and low tides is still larger than average. You will find that one spring and one neap tide per month is larger than the other (growing up by the sea, I'm sure they had different names but I can't find a reference to that now (it is not the same as a perigean spring tide), so possibly this was a local thing).&lt;/p&gt;&#xA;" OwnerUserId="30277" LastEditorUserId="30277" LastEditDate="2024-01-04T13:39:54.440" LastActivityDate="2024-01-04T13:39:54.440" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25850" PostTypeId="2" ParentId="25848" CreationDate="2024-01-04T10:25:31.653" Score="3" Body="&lt;p&gt;Tides are caused by a difference in the gravitational force on the Earth and the ocean. So their magnitude depends on how big that difference is. Their magnitude is not proportional to the strength of gravity here on Earth (of course — you don't feel the dependence of gravity by moon phases, while you do see the tides).&lt;/p&gt;&#xA;&lt;p&gt;The gravitational force on the surface of the Earth depends on the distance to the other celestial body (the Sun of the Moon, doesn't matter). If you look at the difference between gravity at the surface of the Earth and its center, the difference will be greatest at two points — closest and farthest from the body. The &lt;em&gt;direction&lt;/em&gt; of that difference will be away from the center of the Earth. So if all three are collinear, the tidal effects of the Sun and the Moon add up regardless of their order.&lt;/p&gt;&#xA;&lt;p&gt;This is explained in much more detail &lt;a href=&quot;https://earthscience.stackexchange.com/q/16556/20809&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Maybe the following thought experiment clarifies it the best. Imagine the Earth without the Sun but with two Moons, which are equal and always opposite. Their gravitational force will cancel out at the center of the Earth, but their tidal effects will be amplified.&lt;/p&gt;&#xA;" OwnerUserId="20809" LastEditorUserId="20809" LastEditDate="2024-01-04T10:33:09.800" LastActivityDate="2024-01-04T10:33:09.800" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25851" PostTypeId="1" AcceptedAnswerId="25852" CreationDate="2024-01-05T00:43:26.167" Score="1" ViewCount="84" Body="&lt;p&gt;The percentage of oxygen in the atmosphere is 21 percent, according to NASA.gov. I was trying to make a mathematical calculation about oxygen consumption of humans, when I realised that there is a gap in my understanding of the above mentioned fact. Is 21% of the MASS of the atmosphere that of oxygen, or is 21% of the VOLUME of the atmosphere that of oxygen? The mass is not evenly distributed in the atmosphere, and the volume of it is fixed. And for that matter, I have another question, how exactly is the percentage of oxygen in the atmosphere calculated?&lt;/p&gt;&#xA;" OwnerUserId="30282" LastActivityDate="2024-01-06T03:31:46.330" Title="On the percentage of oxygen in the atmosphere" Tags="|atmosphere|oxygen|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25852" PostTypeId="2" ParentId="25851" CreationDate="2024-01-06T03:31:46.330" Score="1" Body="&lt;p&gt;The atmosphere is 20.95% Oxygen by volume, on a dry basis (i.e. without any water vapor).  See &lt;a href=&quot;http://www.atmo.arizona.edu/students/courselinks/fall16/atmo336/lectures/sec1/composition.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; for detailed composition information.&lt;/p&gt;&#xA;&lt;p&gt;Your second question, how is the oxygen percentage calculated, is misguided I believe.  The composition of the atmosphere is measured with gas analyzers, not calculated.&lt;/p&gt;&#xA;" OwnerUserId="8163" LastActivityDate="2024-01-06T03:31:46.330" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25853" PostTypeId="1" CreationDate="2024-01-07T13:26:36.013" Score="3" ViewCount="52" Body="&lt;p&gt;Rossby Waves have different phase- and group velocities.&lt;/p&gt;&#xA;&lt;p&gt;For a pure zonal wave with wave number k they are&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$v_p=\overline u - \frac{\beta}{k^2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$v_g=\overline u + \frac{\beta}{k^2}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;So group velocity is bigger than phase velocity.&lt;/p&gt;&#xA;&lt;p&gt;I'm wondering what speed I should use to calculate the approximate speed of a wave like this:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/nYtVt.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/nYtVt.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It propagates eastward, but since it appears to consist of only a single wave number k (the wavelength is roughly the distance from the east to west coast of the US), why should I use group velocity? The group velocity is the velocity of the envelope of a wave packet tightly centered around a mean wave number. How can I know if a through or ridge (like in the picture) is a wave packet or a single harmonic wave?&lt;/p&gt;&#xA;" OwnerUserId="21047" LastActivityDate="2024-01-07T13:26:36.013" Title="What is the correct velocity to calculate propagation speed of a Rossby Wave?" Tags="|meteorology|atmosphere|atmosphere-modelling|waves|fluid-dynamics|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25854" PostTypeId="1" CreationDate="2024-01-08T09:15:02.890" Score="1" ViewCount="28" Body="&lt;p&gt;If I was near Australia and China when the 10km meteorite hit Chixulub 65 million years ago, the first thing I would have noticed is an earthquake high above magnitude 9, and the ground would shake by perhaps an entire meter up and down and side to side I don't know how fast perhaps at the speed of sound? Is that wrong and what about places closer to the impact? Later there would be tsunamis and the entire planet would be hot and all the super volcanoes be flowing for ages and then it would be freezing for years. So what about the shakes that the birds, rats, dinos, frogs, rivers and trees had to deal with?&lt;/p&gt;&#xA;" OwnerUserId="3315" LastActivityDate="2024-01-08T09:15:02.890" Title="How fast and big would the waves be in the rocks from the Richter scale 10 earthquake at Chixulub" Tags="|geology|earthquakes|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25855" PostTypeId="2" ParentId="14133" CreationDate="2024-01-08T15:55:38.530" Score="3" Body="&lt;p&gt;Here is a &lt;a href=&quot;https://arxiv.org/abs/2310.10904&quot; rel=&quot;nofollow noreferrer&quot;&gt;recent preprint&lt;/a&gt; about a possible super cryovolcano on Pluto. In this study, Cruikshank et al. analyzed the morphology and composition of Kiladze, a wide (~44 km in diameter) depression at Pluto's surface. Based on its morphology and the nature of the deposits surrounding it, the authors conclude that the structure is not an impact crater but rather a caldera which would have erupted almost 1000 km&lt;sup&gt;3&lt;/sup&gt; of water-ice cryomagma:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;In consideration of the size, structure, composition, and youth of Kiladze and surroundings, we interpret this region as a super cryovolcano with a resurgent caldera, having a history of one or more eruptions ejecting 103 km&lt;sup&gt;3&lt;/sup&gt; of cryolava, and possibly an unknown number of eruptions of smaller scale.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;The 1815 eruption of Mount Tambora ejected about 175 km&lt;sup&gt;3&lt;/sup&gt; of material. Volcanologists usually speak in terms of volume of ejected material, which is used to define the &lt;a href=&quot;https://en.wikipedia.org/wiki/Volcanic_explosivity_index&quot; rel=&quot;nofollow noreferrer&quot;&gt;Volcanic Explosivity Index&lt;/a&gt; (VEI) scale, rather than in terms of energy released. Both the Tambora and the proposed Kiladze eruption are classified VEI-7, the former in the lower end, the later in the upper, so I would argue that these events have been similar in terms of energy released. For more details about volume to energy conversion, see &lt;a href=&quot;https://earthscience.stackexchange.com/a/15887/18081&quot;&gt;this answer&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/6gQCz.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/6gQCz.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;em&gt;(a, b) 2D visualization of digital elevation model (DEM) and a triangulated irregular network (TIN) contour map at Kiladze area and surroundings. (c, d) 3D visualization of base map and triangulated irregular network (TIN) map at Kiladze area and surrounding. CC BY Cruikshank et al. (2023).&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2024-01-08T15:55:38.530" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25857" PostTypeId="1" CreationDate="2024-01-09T20:57:44.453" Score="3" ViewCount="25" Body="&lt;p&gt;Coud you help me to resolve this situation? : I have a raw daily averaged sea level time series, as you know when we perform a harmonic analysis (e.g. using T_Tide from MATLAB) we need to put our data in hourly measurements. For example, if you analyze a data series sampled every minute, in T_Tide you must put: 'interval', 1/60.  But in my case I don´t know how to do such analysis since my data are in daily measurements. Any suggestion?&#xA;Thank you so much.&lt;/p&gt;&#xA;" OwnerUserId="27360" LastActivityDate="2024-01-09T20:57:44.453" Title="How to de-tide a daily averaged sea level data?" Tags="|oceanography|sea-level|tides|tide-station|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25858" PostTypeId="1" CreationDate="2024-01-09T23:44:12.487" Score="1" ViewCount="64" Body="&lt;p&gt;I'm also interested in understanding the mechanisms that affect what happens to the various gases in the atmosphere over time. That is, do they get locked away in minerals, stay in the atmosphere, or get blown off into space by the solar wind? How are these mechanisms affected by the planet's mass, distance from the sun, rate of rotation, size and distance of the moon, etc. in the absence of life?&lt;/p&gt;&#xA;&lt;p&gt;For example, &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonate%E2%80%93silicate_cycle#:%7E:text=The%20carbonate%E2%80%93silicate%20geochemical%20cycle,rocks%20by%20metamorphism%20and%20volcanism.&quot; rel=&quot;nofollow noreferrer&quot;&gt;according to Wikipedia's article on the Carbonate–silicate cycle&lt;/a&gt;, Venus lost its water by photodissociation and hydrogen escape, then Venus stopped removing carbon dioxide from its atmosphere, began instead to build it up, and experienced a runaway greenhouse effect. Is life the reason why this didn't also happen on Earth, or is there a different reason?&lt;/p&gt;&#xA;" OwnerUserId="27098" LastActivityDate="2024-02-13T23:01:35.290" Title="What would Earth's atmosphere be like today if life had never existed on it?" Tags="|atmosphere|atmosphere-modelling|sedimentology|carbon-cycle|greenhouse-gases|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25860" PostTypeId="1" CreationDate="2024-01-10T19:44:46.837" Score="4" ViewCount="124" Body="&lt;p&gt;Magnesium is one of the most abundant elements in the Universe and on Earth....&lt;/p&gt;&#xA;&lt;p&gt;So why is it not used in the forms of Magnesium Carbonate and Magnesium Phosphates (Hydroxyapatites, etc.) to make shells and bones?&lt;/p&gt;&#xA;&lt;p&gt;Is it not as widely available in the oceans and/or crust?&lt;/p&gt;&#xA;&lt;p&gt;Is it not quite as 'versatile', chemically speaking, as calcium?&lt;/p&gt;&#xA;&lt;p&gt;Is it not soluble enough, or too soluble?&lt;/p&gt;&#xA;&lt;p&gt;Or are Magnesium compounds just too brittle or weak?&lt;/p&gt;&#xA;&lt;p&gt;I've always wondered about this.....&lt;/p&gt;&#xA;" OwnerUserId="20985" LastActivityDate="2024-01-14T23:08:45.467" Title="Why don't most organisms use magnesium in their shells and bones if it is lighter and more common than calcium?" Tags="|geochemistry|biogeochemistry|geobiology|" AnswerCount="1" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25861" PostTypeId="2" ParentId="25839" CreationDate="2024-01-10T23:04:47.647" Score="0" Body="&lt;p&gt;Humans don't move to places based on the availability of water and food. They bring these things to them as necessary, and that has enabled big cities in places that are otherwise quite dry (say, Las Vegas or Denver) or that do not lend themselves much to agriculture (Fairbanks).&lt;/p&gt;&#xA;" OwnerUserId="5259" LastActivityDate="2024-01-10T23:04:47.647" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25863" PostTypeId="1" CreationDate="2024-01-11T18:04:34.727" Score="2" ViewCount="63" Body="&lt;p&gt;There is a lot of weather forecast data available online, such as this one&#xA;&lt;a href=&quot;https://www.wetter3.de/animation_dt.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.wetter3.de/animation_dt.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But as a student, where do I get according raw GFS data instead of images to do my own (poor) data analysis?&#xA;To give an example: Is raw 500 hPa geopotential height data (see link above) available as a public downloadable file in some specific format or is this paid stuff just for professional organizations?&lt;/p&gt;&#xA;&lt;p&gt;I found a lot of data here, but I'm not sure if this is the right entry point.&#xA;&lt;a href=&quot;https://www.nco.ncep.noaa.gov/pmb/products/gfs/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nco.ncep.noaa.gov/pmb/products/gfs/&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="543" LastEditDate="2024-01-12T08:17:26.660" LastActivityDate="2024-01-13T14:10:17.540" Title="Where can I obtain the raw atmospheric data that weather forecast images are based on?" Tags="|meteorology|weather-forecasting|atmosphere-modelling|gfs|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25864" PostTypeId="1" CreationDate="2024-01-12T16:28:33.123" Score="0" ViewCount="26" Body="&lt;p&gt;Surely wars cause emission of a huge amount of CO2, but does that have a tangible effect in the short-term? For example, can someone claim that while currently there are 2 active wars (in Ukraine and in Gaza) they may have contributed to climate change? Or are the effects negligible to be felt in the short term?&lt;/p&gt;&#xA;" OwnerUserId="28507" LastEditorUserId="6467" LastEditDate="2024-01-12T17:54:00.813" LastActivityDate="2024-01-12T17:54:00.813" Title="Do military conflicts have tangible effects on climate change?" Tags="|climate-change|" AnswerCount="0" CommentCount="0" ClosedDate="2024-01-12T20:05:12.780" ContentLicense="CC BY-SA 4.0" />
  <row Id="25865" PostTypeId="2" ParentId="25863" CreationDate="2024-01-13T14:10:17.540" Score="1" Body="&lt;p&gt;You can fetch GFS from NCEP servers directly. It is documented here:&#xA;&lt;a href=&quot;https://www.nco.ncep.noaa.gov/pmb/products/gfs/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.nco.ncep.noaa.gov/pmb/products/gfs/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;For example, if you want today's 06 UTC run in 0.25-degree resolution, you would go &lt;a href=&quot;https://nomads.ncep.noaa.gov/pub/data/nccf/com/gfs/prod/gfs.20240113/06/atmos/&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt; and look for the files named &lt;code&gt;gfs.t06z.pgrb2.0p25.f*&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;You will get the files in the usual GRIB format. If you are unfamiliar with this format a good starting point would be to look at ecCodes from ECMWF (&lt;a href=&quot;https://github.com/ecmwf/eccodes&quot; rel=&quot;nofollow noreferrer&quot;&gt;github.com/ecmwf/eccodes&lt;/a&gt;).&#xA;If speed or easier access to the data, is important to you I would encourage you to have a look at gribscan (&lt;a href=&quot;https://github.com/gribscan/gribscan&quot; rel=&quot;nofollow noreferrer&quot;&gt;github.com/gribscan/gribscan&lt;/a&gt;)&lt;/p&gt;&#xA;" OwnerUserId="17522" LastActivityDate="2024-01-13T14:10:17.540" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25866" PostTypeId="1" CreationDate="2024-01-13T23:04:20.617" Score="0" ViewCount="100" Body="&lt;p&gt;I am trying to download &lt;a href=&quot;https://atmosphere.copernicus.eu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CAMS&lt;/a&gt; data from CDS and the error in the header is printed. If I understand well a necessary file is missing from my &lt;a href=&quot;https://docs.conda.io/projects/conda/en/latest/user-guide/tasks/manage-environments.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;conda&lt;/a&gt; environment. (I am working in a cluster with CentOS 7).&lt;/p&gt;&#xA;&lt;p&gt;nc-config --all&lt;/p&gt;&#xA;&lt;p&gt;This netCDF 4.8.1 has been built with the following features:&lt;/p&gt;&#xA;&lt;p&gt;--cc            -&amp;gt; x86_64-conda-linux-gnu-cc&#xA;--cflags        -&amp;gt; -I/mnt/..../ditsiaou/0203_385/0203_385/include&#xA;--libs          -&amp;gt; -L/mnt/..../ditsiaou/0203_385/0203_385/lib -lnetcdf&#xA;--static        -&amp;gt; -lmfhdf -ldf -lhdf5_hl -lhdf5 -lm -lcurl -lzip&lt;/p&gt;&#xA;&lt;p&gt;--has-c++       -&amp;gt; no&#xA;--cxx           -&amp;gt;&lt;/p&gt;&#xA;&lt;p&gt;--has-c++4      -&amp;gt; no&#xA;--cxx4          -&amp;gt;&lt;/p&gt;&#xA;&lt;p&gt;--has-fortran   -&amp;gt; yes&#xA;--fc            -&amp;gt; /home/conda/feedstock_root/build_artifacts/netcdf-fortran_1674656969142/_build_env/bin/x86_64-conda-linux-gnu-gfortran&#xA;--fflags        -&amp;gt; -I/mnt/..../ditsiaou/0203_385/0203_385/include -I/..../ditsiaou/0203_385/0203_385/include&#xA;--flibs         -&amp;gt; -L/mnt/..../ditsiaou/0203_385/0203_385/lib -lnetcdff -lnetcdf -lnetcdf&#xA;--has-f90       -&amp;gt; TRUE&#xA;--has-f03       -&amp;gt; yes&lt;/p&gt;&#xA;&lt;p&gt;--has-dap       -&amp;gt; yes&#xA;--has-dap2      -&amp;gt; yes&#xA;--has-dap4      -&amp;gt; yes&#xA;--has-nc2       -&amp;gt; yes&#xA;--has-nc4       -&amp;gt; yes&#xA;--has-hdf5      -&amp;gt; yes&#xA;--has-hdf4      -&amp;gt; yes&#xA;--has-logging   -&amp;gt; no&#xA;--has-pnetcdf   -&amp;gt; no&#xA;--has-szlib     -&amp;gt; no&#xA;--has-cdf5      -&amp;gt; yes&#xA;--has-parallel4 -&amp;gt; no&#xA;--has-parallel  -&amp;gt; no&#xA;--has-nczarr    -&amp;gt; yes&lt;/p&gt;&#xA;&lt;p&gt;--prefix        -&amp;gt; /mnt/..../ditsiaou/0203_385/0203_385&#xA;--includedir    -&amp;gt; /mnt/..../ditsiaou/0203_385/0203_385/include&#xA;--libdir        -&amp;gt; /mnt/..../ditsiaou/0203_385/0203_385/lib&#xA;--version       -&amp;gt; netCDF 4.8.1&lt;/p&gt;&#xA;&lt;p&gt;conda info&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt; active environment : /mnt/..../ditsiaou/0203_385/0203_385&#xA;active env location : /mnt/..../ditsiaou/0203_385/0203_385&#xA;        shell level : 1&#xA;   user config file : /home/d/ditsiaou/.condarc&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;populated config files : /home/d/ditsiaou/.condarc&#xA;conda version : 22.9.0&#xA;conda-build version : not installed&#xA;python version : 3.7.13.final.0&#xA;virtual packages : __linux=3.10.0=0&#xA;__glibc=2.17=0&#xA;__unix=0=0&#xA;__archspec=1=x86_64&#xA;base environment : /mnt/apps/..../linux-centos7-x86_64/gcc-8.2.0/miniconda3-4.6.14-vsbegnyf5k7bjibmedkatrn73vtq4ims  (read only)&#xA;conda av data dir : /mnt/apps/..../linux-centos7-x86_64/gcc-8.2.0/miniconda3-4.6.14-vsbegnyf5k7bjibmedkatrn73vtq4ims/etc/conda&#xA;conda av metadata url : None&#xA;channel URLs : &lt;a href=&quot;https://repo.anaconda.com/pkgs/main/linux-64&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://repo.anaconda.com/pkgs/main/linux-64&lt;/a&gt;&#xA;&lt;a href=&quot;https://repo.anaconda.com/pkgs/main/noarch&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://repo.anaconda.com/pkgs/main/noarch&lt;/a&gt;&#xA;&lt;a href=&quot;https://repo.anaconda.com/pkgs/r/linux-64&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://repo.anaconda.com/pkgs/r/linux-64&lt;/a&gt;&#xA;&lt;a href=&quot;https://repo.anaconda.com/pkgs/r/noarch&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://repo.anaconda.com/pkgs/r/noarch&lt;/a&gt;&#xA;package cache : /mnt/..../ditsiaou/2609_385_intel/2609_385_intel/.conda/pkgs&#xA;/mnt/..../ditsiaou/2023/conda_env/2309_385/2309_385/.conda/pkgs&#xA;/mnt/..../ditsiaou/models/280923v1/2609_385_intel/2609_385_intel/.conda/pkgs&#xA;/mnt/..../ditsiaou/2609_385_intel/2609_385_intel/.conda/pkgs/&#xA;/mnt/..../ditsiaou/0203_385/0203_385/.conda/pkgs&#xA;/mnt/..../ditsiaou/0203_385/0207_385_gcc730/.conda/pkgs&#xA;/mnt/..../ditsiaou/gcc_020223_py385/.conda/pkgs&#xA;/mnt/..../ditsiaou/intel_3101_py385/.conda/pkgs&#xA;envs directories : /mnt/..../ditsiaou/2609_385_intel/2609_385_intel/.conda/envs&#xA;/mnt/..../ditsiaou/2023/conda_env/2309_385/2309_385/.conda/envs&#xA;/mnt/..../ditsiaou/models/280923v1/2609_385_intel/2609_385_intel/.conda/envs&#xA;/mnt/..../ditsiaou/2609_385_intel/2609_385_intel/.conda/envs/&#xA;/mnt/..../ditsiaou/gcc_020223_py385/0203_385/.conda/envs&#xA;/mnt/..../ditsiaou/gcc_020223_py385/0207_385_gcc730/.conda/envs&#xA;/mnt/..../ditsiaou/gcc_020223_py385/.conda/envs&#xA;/home/d/ditsiaou/.conda/envs&#xA;/mnt/apps/..../linux-centos7-x86_64/gcc-8.2.0/miniconda3-4.6.14-vsbegnyf5k7bjibmedkatrn73vtq4ims/envs&#xA;platform : linux-64&#xA;user-agent : conda/22.9.0 requests/2.28.1 CPython/3.7.13 Linux/3.10.0-1160.105.1.el7.x86_64 centos/7.9.2009 glibc/2.17&#xA;UID:GID : 165170:2000&#xA;netrc file : None&#xA;offline mode : False&lt;/p&gt;&#xA;" OwnerUserId="30273" LastEditorUserId="30273" LastEditDate="2024-01-19T13:03:55.947" LastActivityDate="2024-02-18T14:02:20.317" Title="grib_to_netcdf: error while loading shared libraries: libnetcdf.so.11: cannot open shared object file: No such file or directory" Tags="|atmosphere-modelling|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25867" PostTypeId="2" ParentId="25443" CreationDate="2024-01-14T09:43:58.523" Score="1" Body="&lt;p&gt;To cite Bryam Orihuela-Pinto et al. You will see that the collaps of the amoc changes Wind pattern and the heat structure of the oceans. These two factors, along with salinity, are the most important factors responsible for ocean upheaval. In the absence of overturning, this leads to strong accumulations of nutrient-rich deep waters, which are then subject to upwelling due to the inflow of warm waters. This boosts primary production extremely strongly, which in turn leads to increased respiration. Oxygen is consumed during respiration, resulting in suboxic conditions.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Climate projections suggest a weakening or collapse of the Atlantic Meridional Overturning Circulation (AMOC) under global warming, with evidence that a slowdown is already underway. This could have significant ramifications for Atlantic Ocean heat transport, Arctic sea ice extent and regional North Atlantic climate. However, the potential for far-reaching effects, such as teleconnections to adjacent basins and into the Southern Hemisphere, remains unclear. Here, using a global climate model we show that AMOC collapse can accelerate the Pacific trade winds and Walker circulation by leaving an excess of heat in the tropical South Atlantic. This tropical warming drives anomalous atmospheric convection, resulting in enhanced subsidence over the east Pacific and a strengthened Walker circulation and trade winds. Further teleconnections include weakening of the Indian and South Atlantic subtropical highs and deepening of the Amundsen Sea Low. These findings have important implications for understanding the global climate response to ongoing greenhouse gas increases.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-01-14T10:14:43.260" LastActivityDate="2024-01-14T10:14:43.260" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25868" PostTypeId="1" CreationDate="2024-01-14T12:40:55.407" Score="1" ViewCount="18" Body="&lt;p&gt;I want to give lithostragraphic name for a stratovolcanoe rocks. Is it suitable to use &amp;quot;FORMATION&amp;quot; for these rocks, where it composed  of mainly lava, dome lavas, autobreccia, and minor pyroclastic density current units with feeder dykes.&lt;/p&gt;&#xA;" OwnerUserId="15195" LastActivityDate="2024-01-14T12:40:55.407" Title="Is it suitable to use &quot;formation&quot; for mainly lava units as a lithostratigraphic unit?" Tags="|stratigraphy|volcanics|lava|stratovolcanoe|formation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25869" PostTypeId="2" ParentId="13034" CreationDate="2024-01-14T13:55:33.797" Score="1" Body="&lt;p&gt;You are right it is about the angle.&lt;/p&gt;&#xA;&lt;p&gt;there is a limit to how much curvature we can detect without aid and the earth is very very big. so you need to see a lot of the horizon before the curve becomes obvious. lets look at this illustration, it way out of scale but illustrates the point.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/1Hqp3.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1Hqp3.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Note that the closer you are to the surface the shallower the angle and the less length of horizon is visible. The shorter the length of horizon the less we can detect the same curve. its a lot easier to detect the displacement form flat on this circle with a larger arc than with with a small one. The curve is the the same but our eyes don't see curve well we see divergence from flat which gets more and more obvious the larger segment of the circle you can see. the higher you are the larger segment of the circle you can see.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zoM3O.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zoM3O.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LjfAi.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LjfAi.png&quot; alt=&quot;![![enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastActivityDate="2024-01-14T13:55:33.797" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25870" PostTypeId="2" ParentId="17253" CreationDate="2024-01-14T15:47:54.107" Score="1" Body="&lt;p&gt;Differentiation is often spoken of as occurring between mantle and core, but it may also occur between crust and mantle and even within the crust.&lt;/p&gt;&#xA;&lt;p&gt;Tectonic activity leads to this differentiation between the rocky layers of Earth. While we think of this process as mixing crust and mantle together, that mixing is not uniform: denser rock is favored for subduction from crust into mantle and downards through the mantle. Therefore over time lighter rock is favored for the top, or the crust, and even within upper/outer regions of the crust (continental versus ocean crust).&lt;/p&gt;&#xA;&lt;p&gt;This sorting of lighter rock to the top due to nonuniform tectonic mixing then impacts the chemistry of the crust, or at least of the uppermost crust. Felsic rock such as granite, generally containing alkali metals and aluminum (and to some extent also pure silica), is less dense than mafic rock such as basalt which, basically, contains all the other common metals. So felsic rock is most prominent in the upper crust. With the felsic rock come alkali metals and aluminum.&lt;/p&gt;&#xA;&lt;p&gt;More subtly, mafic rock is also variable in density, with &lt;a href=&quot;https://earthscience.stackexchange.com/a/24863/20607&quot;&gt;calcium-rich rock being less dense than more purely magnesium-iron silicates&lt;/a&gt;. So calcium is also enriched in our crust — and also in shells and in our bones and teeth that are made from this crust.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2024-01-26T14:21:25.983" LastActivityDate="2024-01-26T14:21:25.983" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25871" PostTypeId="1" CreationDate="2024-01-14T17:23:30.290" Score="1" ViewCount="30" Body="&lt;p&gt;About a year ago I read about the &amp;quot;arctic oasis of the Lake Hazen&amp;quot; in the Ellesmere Island Wiki article. According to &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/000632079390503S&quot; rel=&quot;nofollow noreferrer&quot;&gt;that article&lt;/a&gt;, it is a thermal oasis. In the nearest Greenland areas, there are mud volcanoes, so, warming up from below such a deep lake as Hazen can be easily understandable.&lt;/p&gt;&#xA;&lt;p&gt;But if you look at the weather map (14 Jan 2024) of the area, you can see, that the area around the lake is warmed up by merely about a pair of degrees, whereas some higher areas are warmed by 10C or even up to 17 degrees.&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;(These warmer spots have a temperature of about -7 - -14C. The background, including the coast, has a temperature of about -24C. The winds here at the moment were all below 5km/h. The cloud map is clean in the whole area. So, there is a clean Polar night both in warm and cold areas. Wetness of the air is below 20%. There are wetter areas to the east, but they haven't higher temperatures. Visibility is 20-30km everywhere)&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;Why numerous mountainous areas on Ellesmere and Axel Heiberg are so much warmer than their surrounding? The reason cannot be the sea current - for they are not on the coast, and the air above the sea has monotonous -24C. The reason cannot be thermals - for if you look at the map of the usual ice/snow coverage, these places are mostly covered by snow, in contrast to colder places. The second reason for the non-thermal source of warmth is that only Lake Hazen is mentioned as a thermal oasis in the literature.&lt;/p&gt;&#xA;&lt;p&gt;The landscape of these islands contains not only arctic deserts but also large areas of tundra, in contrast to Devon Island, which is further to the south. So, this warmth is not a caprice of the moment.&lt;/p&gt;&#xA;&lt;p&gt;Other Canadian islands and Greenland have no such anomalies. Already the near Devon island, or Baffin have the traditional picture of colder weather in the mountains and warmer in the valleys or near warmer sea areas, and the difference itself is noticeably smaller. (Though I had not checked the small islands - they simply haven't a place for such spots)&lt;/p&gt;&#xA;&lt;p&gt;I thought about the effect of the black body - regions, covered by snow, radiate less warmth than the naked areas because of the color... But the other Canadian islands have &lt;a href=&quot;https://en.wikipedia.org/wiki/Nunatak&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;em&gt;nunataks&lt;/em&gt;&lt;/a&gt; (naked stone areas), too, but without any such effects.&lt;/p&gt;&#xA;&lt;p&gt;So, &lt;strong&gt;What is the reason for the existence of numerous very warm (10-17C warmer than background) 5-20km areas on these two large islands?&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/vxvjf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/vxvjf.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/tOX1s.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/tOX1s.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This question is NOT about the well-known Arctic paradox, connected to global climate change. It is about the climate differences of the numerous close localities.&lt;/p&gt;&#xA;" OwnerUserId="13833" LastActivityDate="2024-01-14T17:23:30.290" Title="The reason for numerous warmer spots on Ellesmere and Axel Heiberg" Tags="|climate|arctic|canada|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25872" PostTypeId="2" ParentId="25860" CreationDate="2024-01-14T19:32:43.690" Score="5" Body="&lt;p&gt;First off, magnesium is not more common than calcium where it counts for Earth organisms, namely the crust. By mass calcium is more common in the crust, by atoms they are about equal (the enrichment of calcium in Earth's crust is described &lt;a href=&quot;https://earthscience.stackexchange.com/a/20798/20607&quot;&gt;here&lt;/a&gt;). Plus, at least some organisms might prefer to save their magnesium for chlorophyll, which is rather important for biology in Earth in its own right.&lt;/p&gt;&#xA;&lt;p&gt;Calcium and magnesium are both alkaline earth metals, but their compounds have subtly different properties. Solubility, which us a major consideration for forming stable and robust skeletal structures, is among them. Among carbonates, calcium carbonate has a solubility of &lt;a href=&quot;https://en.wikipedia.org/wiki/Calcium_carbonate&quot; rel=&quot;noreferrer&quot;&gt;&lt;span class=&quot;math-container&quot;&gt;$0.013\text{ g/L}$&lt;/span&gt;&lt;/a&gt; at &lt;span class=&quot;math-container&quot;&gt;$25°\text{C}$&lt;/span&gt;; the corresponding figure for magnesium carbonate is &lt;a href=&quot;https://en.wikipedia.org/wiki/Magnesium_carbonate&quot; rel=&quot;noreferrer&quot;&gt;&lt;span class=&quot;math-container&quot;&gt;$0.139\text{ g/L}$&lt;/span&gt;&lt;/a&gt;. When magnesium carbonate is dissolved in water, much of it is in the form of ion pairs which favors greater solubility and also makes that solubility greater than that predicted from the usual solubility product. Calcium ions, being bulkier, are less effective at forming ion pairs with multiple charged anions. Clearly calcium carbonate is more likely to precipitate from ocean water to form shells, pearls, etc. Even where there is magnesium carbonate, it is often in the form of a double salt with the less soluble calcium carbonate component (dolomite).&lt;/p&gt;&#xA;&lt;p&gt;Phosphates tell a similar story. Wikipedia does not give quantitative data for the solubility if &lt;span class=&quot;math-container&quot;&gt;$\ce{Mg3(PO4)2}$&lt;/span&gt; or &lt;span class=&quot;math-container&quot;&gt;$\ce{Ca3(PO4)2}$&lt;/span&gt;, but the latter has a lower solubility product &lt;a href=&quot;https://www.chm.uri.edu/weuler/chm112/refmater/KspTable.html&quot; rel=&quot;noreferrer&quot;&gt;(&lt;span class=&quot;math-container&quot;&gt;$2×10^{-29}\text{(Ca)}&amp;lt;1×10^{-25}\text{(Mg)}$&lt;/span&gt;)&lt;/a&gt; and again, we would expect ion pairing with a multiple charged anion to favor magnesium phosphate dissolution even more. So as with carbonates, calcium phosphate is easier to precipitate and more resistant to (re)dissolution than the magnesium counterpart.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="2470" LastEditDate="2024-01-14T23:08:45.467" LastActivityDate="2024-01-14T23:08:45.467" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25873" PostTypeId="2" ParentId="25839" CreationDate="2024-01-14T21:34:31.757" Score="1" Body="&lt;p&gt;The main reason why people move to some area or multiply more or less in some area is the already existent distribution and the way of living of the existent population. For example, if there is a cross of two roads, the first one connects large cities A and B and the second one connects also large cities C and D, obviously a new town appears on the cross. The speed of growth of the town depends on the importance of the cities A, B, C, and D in comparison to other cities of the land, the character of goods, transported along the roads, and so on. Naturally, the geographic information is also important.&lt;/p&gt;&#xA;&lt;p&gt;So, the derivations of the population and industries' densities depend on more or less static geographic factors and the researched densities in the wide area. &lt;strong&gt;The dependency on geography alone simply does not exist.&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;We know that complex dependency exists, but we can only guess about its character and make some applications that can model the development, but with great mistakes.&lt;/p&gt;&#xA;&lt;p&gt;For example, in the early Middle Ages in the lands of Eastern Europe, Slavs settled between rivers, on hills, and Ugrofinnish tribes settled along rivers. According to geography alone, they should try to settle in the same places and fight for them. But they had different economic processes, and different customs and could easily coexist, striving for different points in the same area.&lt;/p&gt;&#xA;" OwnerUserId="13833" LastActivityDate="2024-01-14T21:34:31.757" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25874" PostTypeId="2" ParentId="23740" CreationDate="2024-01-14T21:44:02.860" Score="0" Body="&lt;p&gt;You can surely add the mountains of Burma, Afghanistan, Pakistan, and Tajikistan (Pamir) to the picture. They are also the result of the impact, only the direction of the pressure was not perpendicular to the edge of the platform, for India moved not only to the north but a bit to the east, too. So, the mountains are not so high.&lt;/p&gt;&#xA;&lt;p&gt;As for the northern mountains, they are rather the result of the Baykal ridge and the consequent movement of the Tarim craton to the south.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/kzq60.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/kzq60.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13833" LastActivityDate="2024-01-14T21:44:02.860" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25875" PostTypeId="2" ParentId="25858" CreationDate="2024-01-14T21:52:57.303" Score="0" Body="&lt;p&gt;On Earth, it was life that absorbed the CO2 from the atmosphere. But we cannot tell that without life there wouldn't be any other global chemical process that would do the same thing, or something absolutely different that we even cannot imagine. The global processes consist of many reactions and we cannot predict which of them would play the main roles, and in what sequence. Especially while we don't know the exact state of the ancient atmosphere. The explanation postfactum, as in the article mentioned by You, is NOT the real science, let's not forget it. It is merely pre-science. And you are trying to ask the question about the prediction of processes due to the start state - it is a serious question that only a real science can answer.&lt;/p&gt;&#xA;&lt;p&gt;The conditions on Earth and Venus were very different from the times of the Gaian impact, our atmosphere was a thousand times weaker. There is no evidence that so much weaker atmosphere would have the same evolution. We could have an atmosphere evolution similar to Mars or something specific to our planet. Or we could be a snowball like Europe. Don't forget, that some atmospheres can have a negative greenhouse effect.&lt;/p&gt;&#xA;" OwnerUserId="13833" LastEditorUserId="13833" LastEditDate="2024-01-14T22:04:36.063" LastActivityDate="2024-01-14T22:04:36.063" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25876" PostTypeId="1" CreationDate="2024-01-15T18:13:34.023" Score="4" ViewCount="185" Body="&lt;p&gt;I live near a river in the Pacific NW (USA) and it has been cold (low teens °F, around -10°C) for over a week. The river is about 5-6 feet (1.5–1.8 metre) deep and moving fast enough so the river at the surface is completely ice free. The bottom of the river has ice attached to the rocks and occasionally the ice pops off and floats to the surface. This seems to indicate that either the rocks are below freezing or the water is supercooled and forms ice at the rock because the speed of the water at the rock surface is slower.&lt;/p&gt;&#xA;&lt;p&gt;Has there been an analysis of this phenomenon?&lt;/p&gt;&#xA;" OwnerUserId="28036" LastEditorUserId="6" LastEditDate="2024-01-16T08:45:18.967" LastActivityDate="2024-01-16T08:45:18.967" Title="Ice on rocks at bottom of flowing river" Tags="|rivers|thermodynamics|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25877" PostTypeId="1" CreationDate="2024-01-16T03:26:23.307" Score="0" ViewCount="35" Body="&lt;p&gt;I am working with inversion of magnetic data and one colleague of my supervisor has said this about subtracting the IGRF for inversions:&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;””&lt;/p&gt;&#xA;&lt;p&gt;He needs to subtract a value from them to make the dataset closer to 0 centred. The inversion is very sensitive to that number. If you get it wrong it will put material in the padding or at the bottom of the model to compensate.&lt;/p&gt;&#xA;&lt;p&gt;We find dipole anomalies that appear to be only induced and gauge the zero level based on a synthetic model at that latitude.&lt;/p&gt;&#xA;&lt;p&gt;If he needs a quick synthetic modelling package we use pblock - written by the same block who writes potent. Its free and runs on Windows and Wine.&#xA;&lt;a href=&quot;https://www.geoss.com.au/downloads.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.geoss.com.au/downloads.html&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The average rarely cuts it, you'd likely get closer by using the IGRF value but still not close enough.&lt;/p&gt;&#xA;&lt;p&gt;They'll need to estimate it more closely. If they are a geophysicist then just tell them to estimate the zero level for the anomaly and they should know what to do if they have been taught properly. If they are a data scientist pretending to be a geophysicist have them generate a synthetic model for a simple body at the same magnetic latitude as the area to be inverted. Measure the amplitude of the high and the low to get the ratio of positive/negative.&lt;/p&gt;&#xA;&lt;p&gt;Now find a dipole which appears to only have an induced component and measure the range between the high and low and using the ratio from the synthetic model estimate zero. Do it on as many dipoles as possible to get a feel for the average value of zero.&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;&amp;quot;&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;This guy just told me that you can find this method in any geophysics textbook. However, I am unable to find this technique in the literature and he did not develop any further his suggestion (also my background is in geology). Any ideas or suggestions of publications that explain what is he talking about? I looked in textbooks such as Hinze, Dentith and Mudge, Blakely, Isles and Rankin, etc, and could not find it.&lt;/p&gt;&#xA;&lt;p&gt;I was first doing the subtraction of the average value from each magnetic observation to get the data zero centred. I know that I can remove the IGRF from a software process packaging, like Oasis Montaj, but it seems that he is saying to first create synthetic models to then remove the regional signal, which I am unaware of.&lt;/p&gt;&#xA;&lt;p&gt;Thank you in advance.&lt;/p&gt;&#xA;" OwnerUserId="20620" LastActivityDate="2024-01-16T03:26:23.307" Title="Inversion of magnetic data" Tags="|geophysics|inversion|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25879" PostTypeId="1" CreationDate="2024-01-16T10:36:00.357" Score="3" ViewCount="39" Body="&lt;p&gt;Era5 data for wind&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;grib_ls -p shortName,name,paramId,table2Version,indicatorOfParameter era5_wdir-ws.grib&#xA;ws     Wind speed       10   128   10&#xA;ws     Wind speed       10   128   10&#xA;ws     Wind speed       10   128   10&#xA;...&#xA;wdir   Wind direction   3031   3   31&#xA;wdir   Wind direction   3031   3   31&#xA;wdir   Wind direction   3031   3   31&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;So, grib_ls gives the proper variable name.&#xA;Under python, using xarray with cfgrib backend:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;ws_dataset = xr.open_dataset(&#xA;    grib_file_path_wind_str,&#xA;    engine='cfgrib',&#xA;    indexpath='',    # Evita que cfgrib cree un fichero índice&#xA;    backend_kwargs={'filter_by_keys': {'table2Version': 128,&#xA;                                       'indicatorOfParameter': 10}}&#xA;)&#xA;wdir_dataset = xr.open_dataset(&#xA;        grib_file_path_wind_str,&#xA;        engine='cfgrib',&#xA;        indexpath='',&#xA;        backend_kwargs={'filter_by_keys': {'table2Version': 3,&#xA;                                           'indicatorOfParameter': 31}}&#xA;    )&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;And ws_dataset is:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;&amp;lt;xarray.Dataset&amp;gt;&#xA;Dimensions:     (time: 8760, latitude: 13, longitude: 23)&#xA;Coordinates:&#xA;    number      int64 0&#xA;  * time        (time) datetime64[ns] 2010-01-01 ... 2010-12-31T23:00:00&#xA;    step        timedelta64[ns] 00:00:00&#xA;    surface     float64 0.0&#xA;  * latitude    (latitude) float64 30.0 29.75 29.5 29.25 ... 27.5 27.25 27.0&#xA;  * longitude   (longitude) float64 -18.5 -18.25 -18.0 ... -13.5 -13.25 -13.0&#xA;    valid_time  (time) datetime64[ns] ...&#xA;Data variables:&#xA;    ws          (time, latitude, longitude) float32 ...&#xA;Attributes:&#xA;    GRIB_edition:            1&#xA;    GRIB_centre:             ecmf&#xA;    GRIB_centreDescription:  European Centre for Medium-Range Weather Forecasts&#xA;    GRIB_subCentre:          0&#xA;    Conventions:             CF-1.7&#xA;    institution:             European Centre for Medium-Range Weather Forecasts&#xA;    history:                 2024-01-16T10:25 GRIB to CDM+CF via cfgrib-0.9.1...&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;So, the variable name has been properly set, but for wdir_dataset:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;&amp;lt;xarray.Dataset&amp;gt;&#xA;Dimensions:     (time: 8760, latitude: 13, longitude: 23)&#xA;Coordinates:&#xA;    number      int64 ...&#xA;  * time        (time) datetime64[ns] 2010-01-01 ... 2010-12-31T23:00:00&#xA;    step        timedelta64[ns] ...&#xA;    surface     float64 ...&#xA;  * latitude    (latitude) float64 30.0 29.75 29.5 29.25 ... 27.5 27.25 27.0&#xA;  * longitude   (longitude) float64 -18.5 -18.25 -18.0 ... -13.5 -13.25 -13.0&#xA;    valid_time  (time) datetime64[ns] ...&#xA;Data variables:&#xA;    p3031       (time, latitude, longitude) float32 ...&#xA;Attributes:&#xA;    GRIB_edition:            1&#xA;    GRIB_centre:             ecmf&#xA;    GRIB_centreDescription:  European Centre for Medium-Range Weather Forecasts&#xA;    GRIB_subCentre:          0&#xA;    Conventions:             CF-1.7&#xA;    institution:             European Centre for Medium-Range Weather Forecasts&#xA;    history:                 2024-01-16T10:25 GRIB to CDM+CF via cfgrib-0.9.1...&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Why does the grib tool grib_ls get the proper variable name and cfgrib not?&#xA;I have installed both grib tools and python/xarray/cfgrib under a conda environment, and use them from that conda environment.&lt;/p&gt;&#xA;" OwnerUserId="30337" LastActivityDate="2024-01-17T10:07:44.043" Title="cfgrib does not take the proper variable name" Tags="|meteorology|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25880" PostTypeId="1" AcceptedAnswerId="25882" CreationDate="2024-01-17T01:54:58.077" Score="3" ViewCount="181" Body="&lt;p&gt;I had a physics professor that said that it becomes colder after snow because heat from the air is absorbed by the snow as it melts.&lt;/p&gt;&#xA;&lt;p&gt;This makes sense to me in that the snow should lower the temperature from what it would have been had the snow not been on the ground because the phase change of the snow should absorb ambient heat, but it does not make sense to me in that the ambient temperature should be lower than when it was snowing in an absolute sense, because the temperature would have to be &amp;gt; 0 C for the snow to melt and the snow would have to have been falling at a temperature &amp;lt; 0 C.&lt;/p&gt;&#xA;&lt;p&gt;Does anyone know if temperature is lower following snow than it is during snow and if it is lower whether my professor got the mechanism wrong? Or, if there is something that I'm not accounting for?&lt;/p&gt;&#xA;&lt;p&gt;Alternatively, does anyone know of good atmospheric data in the United States that I could use to confirm or disprove the correlation? (I would need temperature, precipitation, and whether it was snowing or not - more granular the better - I have strong python / data science skills and could do the confirmation myself).&lt;/p&gt;&#xA;" OwnerUserId="30338" LastActivityDate="2024-02-24T08:01:41.893" Title="colder after snow" Tags="|temperature|precipitation|snow|" AnswerCount="2" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25881" PostTypeId="1" CreationDate="2024-01-17T09:35:23.810" Score="2" ViewCount="37" Body="&lt;p&gt;We all know that ERA5 is a reanalysis product based on a frozen version of IFS, so the results coming from both models are kind of comparable because they at least use a similar setup in the dynamical core and physics parametrizations.&lt;/p&gt;&#xA;&lt;p&gt;However, I cannot find the analogue of ERA5 for GFS. The only products that I found are the operational analysis of GFS (but this is NOT a reanalysis) and the CFSR reanalysis, which is instead based on CFS, so the climate fully-coupled version of GFS at lower resolution.&lt;/p&gt;&#xA;&lt;p&gt;While I believe CFSR is the closest we can get, it is not exactly the same thing because it uses a completely different model and is not updated.&lt;/p&gt;&#xA;&lt;p&gt;As I'm not using GFS products often I may just be confused by their architecture. So...is there or not an ERA5 counterpart for GFS?&lt;/p&gt;&#xA;" OwnerUserId="27107" LastActivityDate="2024-01-17T09:35:23.810" Title="What is the ERA5 counterpart for GFS?" Tags="|gfs|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25882" PostTypeId="2" ParentId="25880" CreationDate="2024-01-17T10:04:05.553" Score="4" Body="&lt;p&gt;I think you're mixing two things together. There are generally 2 processes that correlate low temperatures during and after a snowfall, but they are separated. These are both based on physical laws but also on my personal experience :)&lt;/p&gt;&#xA;&lt;p&gt;First of all, during a strong snowfall (the same usually does not happen for light snowfall) the snowflakes have to fall through different layers to finally arrive at the surface. If the temperature at the surface is not extremely low (and this is the case for most mid-latitudes snowfalls) most of the snowflakes will melt, at least partially, when falling. This melting process is what causes a sudden drop of temperature that can be observed during strong snowfall.&lt;/p&gt;&#xA;&lt;p&gt;To observe this you need to get temperature data with high sampling (at least 5 minutes) because the process is really fast and hourly observations will not capture it. Plus, it is not always visible because it really depends on the temperature you have at the beginning of the snowfall. If you're starting from 1/2°C, you'd see a strong drop to values close to 0. If you're already starting from temperatures close to 0 or negative probably you won't see a change at all.&lt;/p&gt;&#xA;&lt;p&gt;Atmospheric vertical profilers can also catpure snow melting and associated temperature drops, but this kind of data is obviously hard to find.&lt;/p&gt;&#xA;&lt;p&gt;Second, the process of surface cooling after a snowfall is mostly related to radiative balance. In fact, after a strong snowfall usually the sky clears up (this is because again in mid-latitudes strong snowfall are associated with cold fronts moving in and bringing dry and cold air from the north). This enhances surface cooling because there are no clouds reflecting the infrared radiation irradiated towards the sky. Snow (especially when fresh) is really effective in radiate energy, way more than bare soil, and that's why the surface temperature decreases rapidly. Also, during the day, snow reflects a lot of incoming solar radiation, preventing the surface from heating up. If the snow persists for many days this process amplifies and can lead to surface thermal inversions. There are some other processes causing cooling at the surface, like snow sublimation and snow melting.&lt;/p&gt;&#xA;" OwnerUserId="27107" LastActivityDate="2024-01-17T10:04:05.553" CommentCount="10" ContentLicense="CC BY-SA 4.0" />
  <row Id="25883" PostTypeId="2" ParentId="25879" CreationDate="2024-01-17T10:07:44.043" Score="2" Body="&lt;p&gt;&lt;code&gt;cfgrib&lt;/code&gt; uses &lt;code&gt;eccodes&lt;/code&gt; under the hood, and not anymore the deprecated &lt;code&gt;grib_api&lt;/code&gt; you're using, so that may be the source of the difference you're seeing.&#xA;However, regardless of &lt;code&gt;eccodes&lt;/code&gt; or &lt;code&gt;grib_api&lt;/code&gt; the name of the variables only depends on the GRIB tables installed and shouldn't depend on the executable used. Understanding which grib tables are used is a pain in the ...., especially because the way &lt;code&gt;cfgrib&lt;/code&gt; is installed (conda, pip...?) would mean it also installed other dependencies that may come with different GRIB tables.&#xA;Plus, &lt;code&gt;cfrgib&lt;/code&gt; is doing some additional preprocessing when interpreting the data as hypercubes.&lt;/p&gt;&#xA;&lt;p&gt;If you're using only &lt;code&gt;cfgrib&lt;/code&gt; I'd suggest you to forget about &lt;code&gt;grib_ls&lt;/code&gt; and use the variable name that &lt;code&gt;cfgrib&lt;/code&gt; is finding, which shouldn't change if you don't make any modification in the environment where it is installed.&lt;/p&gt;&#xA;" OwnerUserId="27107" LastActivityDate="2024-01-17T10:07:44.043" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25885" PostTypeId="1" CreationDate="2024-01-18T18:26:03.157" Score="2" ViewCount="91" Body="&lt;p&gt;When the Earth was hit by a meteor in Jurassic era, did it change its orbit or not?&lt;/p&gt;&#xA;&lt;p&gt;Here is a National Geograpic video about the event:&#xA;&lt;a href=&quot;https://www.youtube.com/watch?v=dNRTtLLuNM8&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=dNRTtLLuNM8&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29817" LastEditorUserId="7064" LastEditDate="2024-01-19T11:40:47.573" LastActivityDate="2024-01-19T11:40:47.573" Title="When the Earth was hit by a meteor in Jurassic era, did it change its orbit or not?" Tags="|earth-history|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25886" PostTypeId="2" ParentId="25885" CreationDate="2024-01-18T19:00:40.193" Score="1" Body="&lt;p&gt;Not by a lot. Meteors have only a tiny fraction of Earth's mass, so at entry velocities roughly equivalent to our own orbital speed around the Sun (which would be typical of meteors) there is only a tiny impact on Earth's orbit. It would be something like what happened in the 1990s when Comet &lt;a href=&quot;https://www.britannica.com/topic/Comet-Shoemaker-Levy-9&quot; rel=&quot;nofollow noreferrer&quot;&gt;Shoemaket-Levy 9 was broken up and flew to its demise at Jupiter&lt;/a&gt;; the surface effects were spectacular but the impact on the orbit of the whole mass was negligible.&lt;/p&gt;&#xA;&lt;p&gt;True, the meteor strike that apparently killed off most of the dinosaurs (what we now call birds may have evolved from survivors) had major impacts on the climate that could have led to this extinction. But both the biosphere and the troposphere (the latter is where weather occurs) are tiny fractions of Earth as a whole that were most directly exposed to the impact; the vast bulk of Earth's mass and volume went on about its business hardly affected.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2024-01-18T19:00:40.193" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25887" PostTypeId="2" ParentId="25885" CreationDate="2024-01-18T22:56:38.920" Score="3" Body="&lt;p&gt;Undetectably.&lt;/p&gt;&#xA;&lt;p&gt;The mass of the Chicxulub impactor is estimated at about &lt;span class=&quot;math-container&quot;&gt;$m_1=10^{13}  \ kg$&lt;/span&gt;. The Earth's mass is nearly &lt;span class=&quot;math-container&quot;&gt;$m_2=6 \cdot 10^{24}\ kg$&lt;/span&gt;, while their velocities were similar (same order of magnitude).&lt;/p&gt;&#xA;&lt;p&gt;Therefore the former played a very small effect in both the conservation of momentum&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$m_1 \cdot v_1 + m_2 \cdot v_2 = (m_1+m_2) \cdot v_{final}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;and the conservation of energy after an inelastic collision&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$m_1 \cdot v_1^2  + m_2 \cdot v_2^2 = (m_1+m_2) \cdot v_{final}^2 $&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;This yields (some assumptions made for this example) a change in Earth's velocity of &lt;span class=&quot;math-container&quot;&gt;$v_{final}-v_2 ~= 6  \cdot 10^{-7} km/h$&lt;/span&gt; , thirteen orders of magnitude smaller than the average orbital velocity of the Earth, &lt;span class=&quot;math-container&quot;&gt;$107,000 \ km/h$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Undetectable after 65 million years and definitely negligible in comparison to many other changes in orbital speed such as those exerted by the Moon and other planets.&lt;/p&gt;&#xA;" OwnerUserId="1379" LastEditorUserId="2470" LastEditDate="2024-01-19T06:31:42.850" LastActivityDate="2024-01-19T06:31:42.850" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25888" PostTypeId="1" CreationDate="2024-01-19T10:02:37.653" Score="0" ViewCount="19" Body="&lt;p&gt;I should know where clouds form in the atmosphere from the skew-T diagram below. The anwer should be that there is a big stromcloud from a height of 300hPa to 900hPa, but I don't get why.&lt;/p&gt;&#xA;&lt;p&gt;My reasoning was as follows: the left black line is the dew point temperature, while the right black line is the actual air temperature in the atmosphere. The blue line represents a particle that rises adiabatically from the ground. As long as the blue line is on the right of the right black line, the temperature of the air parcel is higher than the temperature of the surrounding air and the parcel keeps rising. This means an air parcel keeps rising adiabatically until it reaches a height of 930hPa.&lt;/p&gt;&#xA;&lt;p&gt;But the air is only saturated from 300hPa to 600hPa, because only there the air temperature is close enough to the dew point temperature.&#xA;Why is it then that clouds form above that height? Is it because the saturated air is lifted up due to convection (the air parcel keeps rising until 930hPa)?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qfWHj.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qfWHj.png&quot; alt=&quot;Skew-T&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="30346" LastActivityDate="2024-01-19T10:02:37.653" Title="How do I know where clouds form from a skew-T diagram?" Tags="|meteorology|weather-forecasting|clouds|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25889" PostTypeId="2" ParentId="25866" CreationDate="2024-01-19T10:16:37.507" Score="0" Body="&lt;p&gt;This question will likely be deleted because there's too little information to answer it and it's really more a question for your cluster support/colleagues.  In the meantime...&lt;/p&gt;&#xA;&lt;p&gt;The shared library &lt;code&gt;libnetcdf.so.11&lt;/code&gt; isn't visible in the environment where you're executing the program.  This may be because,&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The cluster doesn't have &lt;code&gt;netcdf&lt;/code&gt; installed in the default user environment&lt;/li&gt;&#xA;&lt;li&gt;You don't have &lt;code&gt;netcdf&lt;/code&gt; installed in the Conda environment you have active when you run the program (IIRC installing &lt;code&gt;cdsapi&lt;/code&gt; doesn't install &lt;code&gt;netcdf&lt;/code&gt; as a dependency)&lt;/li&gt;&#xA;&lt;li&gt;You don't have the right Conda environment active when you run your program (people often miss this if they're submitting jobs to a cluster via SLURM, PBS, etc)&lt;/li&gt;&#xA;&lt;li&gt;Your Conda environment contains a mixture of incompatible package versions (this can happen if you've been manually installing/updating individual packages)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;It's worth running things like &lt;code&gt;conda info&lt;/code&gt; and &lt;code&gt;nc-config --all&lt;/code&gt; at the start of your script to diagnose what the shell environment is at run time.&lt;/p&gt;&#xA;&lt;p&gt;My install of NetCDF v4.8.1 comes with &lt;code&gt;libnetcdf.so.19&lt;/code&gt;.  As your &lt;code&gt;grib_to_netcdf&lt;/code&gt; is looking for &lt;code&gt;libnetcdf.so.11&lt;/code&gt; I suspect that it was compiled against an earlier version of NetCDF, probably something like v4.4.  If you've compiled it yourself, you need to make sure the Conda environment is active when you do the the configure step so that it sees the correct version.  Even then you may need to tell configure more explicitly where to look for the correct NetCDF libraries.&lt;/p&gt;&#xA;" OwnerUserId="106" LastEditorUserId="106" LastEditDate="2024-01-19T13:56:21.850" LastActivityDate="2024-01-19T13:56:21.850" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25890" PostTypeId="1" AcceptedAnswerId="25985" CreationDate="2024-01-19T12:59:10.933" Score="1" ViewCount="72" Body="&lt;p&gt;I am currently struggling to really understand geopotential height on a conceptual level.&lt;br /&gt;&#xA;Let's say we look at the geopotential height of 500hPa over Europe, where it is usually around 5.5km.&lt;br /&gt;&#xA;Does it mean that at a height of 5.5km the remaining air column (above 5.5km) exerts a pressure of 500hPa?&lt;/p&gt;&#xA;" OwnerUserId="30349" LastActivityDate="2024-02-19T19:30:05.643" Title="Explanation of geopotential height" Tags="|meteorology|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25891" PostTypeId="1" CreationDate="2024-01-19T17:06:01.103" Score="1" ViewCount="34" Body="&lt;p&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Agassiz&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake Agassiz&lt;/a&gt; and &lt;a href=&quot;https://en.wikipedia.org/wiki/Lake_Ojibway&quot; rel=&quot;nofollow noreferrer&quot;&gt;Lake_Ojibway&lt;/a&gt; drained around the time of the &lt;a href=&quot;https://en.wikipedia.org/wiki/8.2-kiloyear_event&quot; rel=&quot;nofollow noreferrer&quot;&gt;8.2 kiloyear event&lt;/a&gt;, &lt;a href=&quot;https://doi.org/10.1016/j.quascirev.2021.107269&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;A framework for the timing of the final meltwater outbursts from glacial Lake Agassiz-Ojibway, Etienne Brouard, Martin Roy, Pierre-Marc Godbout, Jean J. Veillette, Quaternary Science Reviews, Volume 274, 2021, 107269, ISSN 0277-3791, https://doi.org/10.1016/j.quascirev.2021.107269.&quot;&gt;perhaps in a couple of pulses&lt;/a&gt;, the first subglacially and the second when the glacial ice dam finally broke. Clearly these pulses were fast on a geological time scale, but how fast were they?&lt;/p&gt;&#xA;&lt;p&gt;I found &lt;a href=&quot;https://doi.org/10.1029/2021GL093919&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;Catastrophic Drainage From the Northwestern Outlet of Glacial Lake Agassiz During the Younger Dryas, S. L. Norris et al., (2021). Geophysical Research Letters, 48, e2021GL093919.&quot;&gt;one study&lt;/a&gt; reported that a flow through the Clearwater Lower Athabasca Spillway took 6-9 months.  Is this a lower bound on the length of the second pulse?&lt;/p&gt;&#xA;" OwnerUserId="27775" LastActivityDate="2024-01-19T17:06:01.103" Title="How fast did Lake Agassiz and Lake Ojibway drain?" Tags="|ice-age|glaciation|lakes|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25892" PostTypeId="2" ParentId="25890" CreationDate="2024-01-19T18:03:59.373" Score="0" Body="&lt;p&gt;&lt;strong&gt;Not exactly&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;The medium atmospheric pressure at sea level is 1013.25 hPa. 1013.25 - 500 = 513.25 hPa, which is close to 500 hPa, but is not the same.&#xA;The medium atmospheric pressure at sea level is a universal constant, not dependent on the place. Oh, sorry, of course, it IS dependent, but only if we count with precision, far than unreachable by meteorology medium numbers.&lt;/p&gt;&#xA;" OwnerUserId="13833" LastActivityDate="2024-01-19T18:03:59.373" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25893" PostTypeId="2" ParentId="25718" CreationDate="2024-01-19T21:26:11.670" Score="0" Body="&lt;p&gt;I don't know the answer to every of your questions but I will answer as much as possible.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;1) Non-convective clouds&lt;/strong&gt; (also called stratiform clouds):&lt;/p&gt;&#xA;&lt;p&gt;i) In most cases, the relative humidity (RH) of the air is the best indicator for cloud formation. The vapour in the air would theoretically only condensate into clouds when the RH of the air is 100% (and the air is saturated). But because the air contains a lot of particles (condensation nuclei) where water molecules can stick to, this helps condensation a lot and you can start seeing clouds from a relative humidity of around 80%.&lt;/p&gt;&#xA;&lt;p&gt;ii) Normally not, stratiform clouds only form in a stable atmosphere, where the formation occurs because of the rise in relative humidity and not because of convection.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;2) Convective clouds:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I'm sorry but there I can't answer any of your questions.&lt;/p&gt;&#xA;" OwnerUserId="30346" LastEditorUserId="30346" LastEditDate="2024-01-19T21:49:24.183" LastActivityDate="2024-01-19T21:49:24.183" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25894" PostTypeId="1" AcceptedAnswerId="25897" CreationDate="2024-01-20T10:37:54.680" Score="6" ViewCount="560" Body="&lt;p&gt;I found this figure in the paper: &lt;a href=&quot;https://royalsocietypublishing.org/doi/10.1098/rsta.2022.0196&quot; rel=&quot;noreferrer&quot;&gt;&lt;em&gt;Atlantic overturning: new observations and challenges&lt;/em&gt;&lt;/a&gt; by Srokosz et al. I wonder what kind of projection this is and what the advantages of it are? It looks to me as if the surface orgin. Do you have more information&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FUXtG.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FUXtG.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;(Fig from: Srokosz et al)&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="18088" LastEditDate="2024-01-20T12:50:27.617" LastActivityDate="2024-01-20T17:15:54.697" Title="What kind of projection is that?" Tags="|mapping|projection|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25897" PostTypeId="2" ParentId="25894" CreationDate="2024-01-20T17:15:54.697" Score="8" Body="&lt;p&gt;It looks to me like a &lt;a href=&quot;https://en.wikipedia.org/wiki/Sinusoidal_projection&quot; rel=&quot;noreferrer&quot;&gt;sinusoidal projection&lt;/a&gt; centred on -30°W, with edges at -90°W and 30°E. For that projection, the length of the parallels goes as cos(latitude), so we expect the ratio of the widths of the map at 75°S and at the equator to be 0.26, which agrees exactly with my quick measurement of the figure.&lt;/p&gt;&#xA;&lt;p&gt;The sinusoidal projection is equal area, but I think in this case they also like it because its east-west scale is constant. All the labeled lines on the map are roughly east-west, so their relative lengths on the map are all roughly correct. For example, we can immediately see that real length of the &amp;quot;SAMBA 34.5°S&amp;quot; track is more than twice as long as the &amp;quot;NOAC 47°N&amp;quot; track.&lt;/p&gt;&#xA;" OwnerUserId="27775" LastActivityDate="2024-01-20T17:15:54.697" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25898" PostTypeId="2" ParentId="20921" CreationDate="2024-01-20T20:39:37.900" Score="1" Body="&lt;p&gt;I used go-cart.com to generate a cartogram showing every country the same size. It looks like this:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/uatTG.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/uatTG.png&quot; alt=&quot;World cartogram showing every country the same size&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Generated today at &lt;a href=&quot;https://go-cart.io/cartogram&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://go-cart.io/cartogram&lt;/a&gt; - Gastner MT, Seguy V, More P. Fast low-based algorithm for creating density-equalizing map projections. Proc Natl Acad Sci USA 115(10):E2156–E2164 (2018).&lt;/p&gt;&#xA;" OwnerUserId="30358" LastActivityDate="2024-01-20T20:39:37.900" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25899" PostTypeId="2" ParentId="14397" CreationDate="2024-01-21T02:33:13.770" Score="0" Body="&lt;p&gt;The gradient is about 25C/km on average. So about 4000m down, the temperature would be around 100C. The exact gradient varies with location on the planet, of course, but this is the average.&lt;/p&gt;&#xA;&lt;p&gt;A concrete example data-point is the KTB superdeep borehole (German Continental Deep Drilling Programme, 1987–1995) at Windischeschenbach in northern Bavaria. It was drilled to a depth of 9,101 metres (29,859 ft), reaching temperatures of more than 260 °C (500 °F). (Source: Wikipedia).&lt;/p&gt;&#xA;" OwnerUserId="30363" LastActivityDate="2024-01-21T02:33:13.770" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25900" PostTypeId="1" AcceptedAnswerId="25903" CreationDate="2024-01-21T07:27:23.413" Score="2" ViewCount="67" Body="&lt;p&gt;I want to check the precipitation, temperature, and rainfall data of South Asian locations.&lt;/p&gt;&#xA;&lt;p&gt;I downloaded the data from: &lt;a href=&quot;https://www.ncei.noaa.gov/access/search/data-search/global-hourly?stations=44454099999&amp;amp;pageNum=2&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncei.noaa.gov/access/search/data-search/global-hourly?stations=44454099999&amp;amp;pageNum=2&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, I am having difficulty understanding the units.&lt;/p&gt;&#xA;&lt;p&gt;For example the Temperature has data in the column as&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/MZKVY.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/MZKVY.png&quot; alt=&quot;Temp data&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I can't understand in what unit the data is. Can anyone tell me? Also how to check precipitation. I tried reading manual but didn't understand it.&lt;/p&gt;&#xA;" OwnerUserId="20906" LastActivityDate="2024-01-22T10:01:20.193" Title="Units of meteorological data from the NOAA website" Tags="|meteorology|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25903" PostTypeId="2" ParentId="25900" CreationDate="2024-01-22T10:01:20.193" Score="6" Body="&lt;p&gt;You should read the documentation available &lt;a href=&quot;https://www.ncei.noaa.gov/data/global-hourly/doc/isd-format-document.pdf&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;For some reason (probably just legacy) NOAA uses really weird encoding for many variables. In the case of the temperature the value after the comma represents the quality code (1 means it passed all quality control checks), while the rest of the numeric is scaled by a 10 factor.&#xA;Again, don't ask me why... :)&lt;/p&gt;&#xA;&lt;p&gt;But stop! Don't implement something to decode this data. Other people already thought about this and made some packages that let you parse the data directly without worrying about the format.&lt;/p&gt;&#xA;&lt;p&gt;Have a look &lt;a href=&quot;https://www.visualcrossing.com/resources/documentation/weather-data/how-we-process-integrated-surface-database-historical-weather-data/&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;, &lt;a href=&quot;https://pypi.org/project/isd/&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt; and &lt;a href=&quot;https://pypi.org/project/eeweather/&quot; rel=&quot;noreferrer&quot;&gt;here&lt;/a&gt;. There are many other packages that let you fetch this kind of data online.&lt;/p&gt;&#xA;" OwnerUserId="27107" LastActivityDate="2024-01-22T10:01:20.193" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25904" PostTypeId="1" CreationDate="2024-01-22T16:33:10.430" Score="1" ViewCount="82" Body="&lt;p&gt;I have limited experience with the different SEG file formats and I was hoping if someone could shed some light on the current preffered file formats used in software applications and for sharing seismic data please? My current understanding is that the following 3 formats are predominantly used:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;&lt;p&gt;SEG-Y: a flexible and widely supported format used by different applications. Recently updated and widely documented. The go to format for processing and sharing?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;SEG-D: a stricter format and (only?) used for data acquistion.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;SEG-2: less documentation available and less widely supported. A depreciated / obsolete format?&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Any corrections or clarifications, especially on the use of the SEG-2 format, would be much appreicated.&lt;/p&gt;&#xA;" OwnerUserId="28154" LastActivityDate="2024-01-25T13:53:22.247" Title="SEG-2 vs SEG-Y file formats" Tags="|geophysics|seismology|seismic|open-data|data-formats|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25905" PostTypeId="1" CreationDate="2024-01-22T16:38:55.343" Score="1" ViewCount="20" Body="&lt;p&gt;I am working with NEXRAD radar data, and I am trying to plot the U and V wind velocity for each point on a grid. There is a channel in the data called &amp;quot;Velocity&amp;quot; described as &amp;quot;&lt;a href=&quot;https://www.ncei.noaa.gov/products/radar/next-generation-weather-radar&quot; rel=&quot;nofollow noreferrer&quot;&gt;A measure of the radial component of the wind either toward the radar (negative values) or away from the radar (positive values)&lt;/a&gt;&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;I am using the &lt;a href=&quot;https://arm-doe.github.io/pyart/notebooks/mapping_data_to_a_cartesian_grid.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Py-Art library to create a grid&lt;/a&gt; of this velocity data. Now that I have a grid of the velocity (m/s) and angle (theta) for each point on my grid, can I simply calculate the U and V velocties with sin and cos?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/hxwOs.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/hxwOs.png&quot; alt=&quot;Calculating U and V components&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="30368" LastActivityDate="2024-01-22T16:38:55.343" Title="Is this the correct way to extract U and V wind components from NEXRAD weather radar?" Tags="|meteorology|wind|python|radar|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25906" PostTypeId="1" AcceptedAnswerId="25920" CreationDate="2024-01-22T18:46:19.260" Score="6" ViewCount="130" Body="&lt;p&gt;Wikipedia &lt;a href=&quot;https://en.wikipedia.org/wiki/Gotthard_Base_Tunnel&quot; rel=&quot;nofollow noreferrer&quot;&gt;article&lt;/a&gt; says about the Gotthard Base Tunnel:&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;It is the deepest railway tunnel in the world, with a maximum depth of 2,450 m (8,040 ft), comparable to that of the deepest mines on Earth. Without ventilation, the temperature inside the mountain reaches 46 °C (115 °F).&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;More authoritative source with detailed temperature profile, a paper by L. Rybach and A. Busslinger (&lt;a href=&quot;https://www.hbi.ch/fileadmin/user_upload/unternehmen/publikationen/04_Verification..._WTC-2013_Genf.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;pdf&lt;/a&gt;) gives the following diagram:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/87M4l.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/87M4l.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;What is the cause of the elevated temperature? Why does temperature follow depth below surface despite virtually uniform height above sea level of the tunnel?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;In quite simplified model I have homogeneous (the same thermal properties, geothermal gradient etc.) rock with heat flow (conduction only) from the bottom kept at some high temperature (say 1000 °C) to the surface with average annual temperature say 10 °C. Isotherm 50 °C is at some depth below horizontal surface (left diagram, not to scale). Does the isotherm follows surface even in mountains?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/TqHfB.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/TqHfB.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18490" LastEditorUserId="18490" LastEditDate="2024-01-24T09:39:16.417" LastActivityDate="2024-01-26T19:07:49.467" Title="What determines rock temperature inside mountains?" Tags="|mountains|geothermal-heat|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25909" PostTypeId="1" CreationDate="2024-01-24T08:24:32.327" Score="1" ViewCount="37" Body="&lt;p&gt;What would be the behavior of seismic waves when it hit the geological media?&lt;/p&gt;&#xA;&lt;p&gt;The waves coming from a source hits different boundaries with different energies, the wave will be reduced in energy by then (let us say at boundary number 100), the wave will reflect back due to changes in rock physical properties and so on, the reflected wave will pass through boundary 99, I am pretty sure it will not just pass and it will face different boundary (99) with low energy, and so on with boundaries 98, 88, 87..etc. The issue is how we're going to detect boundary 100, what will be the equation for it?&lt;/p&gt;&#xA;&lt;p&gt;I have been revising the well known Zoeppritz and Shuey equations, and they didn't give more details on this.&lt;/p&gt;&#xA;" OwnerUserId="30373" LastEditorUserId="5513" LastEditDate="2024-01-25T09:56:24.333" LastActivityDate="2024-01-25T09:56:24.333" Title="What happens to seismic waves reflected back to the surface?" Tags="|geology|geophysics|waves|seismic|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25910" PostTypeId="2" ParentId="25742" CreationDate="2024-01-24T09:51:05.177" Score="3" Body="&lt;p&gt;What you are looking for is called the &lt;em&gt;Magnitude of Completeness&lt;/em&gt; or &lt;em&gt;Completeness Magnitude&lt;/em&gt;.&#xA;There are several ways to estimate this quantity, one of the common ways is to look at the power law distribution the events such as earthquakes are supposed to follow, and check below which magnitude the actual detected distribution begins to deviate from the theoretical case.&lt;/p&gt;&#xA;&lt;p&gt;See e.g. &lt;a href=&quot;https://pubs.geoscienceworld.org/ssa/bssa/article/95/2/684/146883/Assessing-the-Quality-of-Earthquake-Catalogues&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://pubs.geoscienceworld.org/ssa/bssa/article/95/2/684/146883/Assessing-the-Quality-of-Earthquake-Catalogues&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;As mentioned in other comments, this value varies greatly depending on the catalogue or network you are looking at. There is also some variability depending on how the value is calculated.&lt;/p&gt;&#xA;&lt;p&gt;Just as rough numbers: for an arbitrary earthquake happening anywhere on the planet (i.e. global catalogue), the completeness magnitude is around 5.5. For local networks this value can improve to between 2 to 4. For local network specifically designed to monitor active areas, such as in California, Japan, this value can be from 1 to 2.&lt;/p&gt;&#xA;" OwnerUserId="30374" LastActivityDate="2024-01-24T09:51:05.177" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25913" PostTypeId="2" ParentId="24891" CreationDate="2024-01-24T21:10:20.183" Score="2" Body="&lt;p&gt;Interesting question. This time as often reported is referred to as the &lt;em&gt;origin time&lt;/em&gt;, and ideally this should really correspond to the start of the rupture (rupturing of the fault, breaking of the materials). See e.g. &lt;a href=&quot;https://gfzpublic.gfz-potsdam.de/rest/items/item_4109_1/component/file_4110/content&quot; rel=&quot;nofollow noreferrer&quot;&gt;this document&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Most networks and earthquake services automatically determine this origin time together with the location of the earthquake simply by fitting the arrival times of the seismic waves recorded at the stations. This means finding the location and origin time of the earthquake &lt;span class=&quot;math-container&quot;&gt;$(x_0,y_0,z_0,t_0)$&lt;/span&gt; that best fits the recorded arrival times. This procedure views the earthquake source as a dimensionless point, and I could imagine that the result might differ slightly from the actual start time of rupture, especially for large ruptures and large earthquakes.&lt;/p&gt;&#xA;&lt;p&gt;This result might be improved using further techniques such as finite-fault inversion (see e.g. &lt;a href=&quot;https://pubs.geoscienceworld.org/ssa/bssa/article/92/4/1192/120765/Source-Description-of-the-1999-Hector-Mine&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt;), in which one tries to estimate the whole rupturing process on the fault. I won't go into detail but the parameterization usually requires further prior information on the earthquake, such as the orientation and size of the fault, etc.&lt;/p&gt;&#xA;" OwnerUserId="30374" LastActivityDate="2024-01-24T21:10:20.183" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25914" PostTypeId="1" CreationDate="2024-01-25T11:26:34.553" Score="5" ViewCount="147" Body="&lt;p&gt;I am trying to compute daily climatology of ERA5 data, but without using &lt;strong&gt;append&lt;/strong&gt; and &lt;strong&gt;concat&lt;/strong&gt; so that I do not consume a lot of memory.&lt;/p&gt;&#xA;&lt;p&gt;My idea was to read every file and update it by adding the next file and then dividing it by 2 in a loop. To do this, I tried to use the += operator. I am writing it in the code-snippet below. Since, I am reading inside the loop, I am not really updating it. Can anyone please tell me, how I can update &lt;strong&gt;rain_clim&lt;/strong&gt; as I read along. Many thanks.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;rain_clim=[]&#xA;for i in flood_years:&#xA;        rain_clim=xr.open_dataset('Rainfall-'+str(i)+'.nc')&#xA;        rain_clim+=rain_clim&#xA;        rain_clim=rain_clim/2```&#xA;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="20531" LastActivityDate="2024-01-25T16:09:21.483" Title="Compute ERA5 daily climatology without consuming lot of memory" Tags="|climatology|era|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25915" PostTypeId="2" ParentId="25914" CreationDate="2024-01-25T16:06:49.977" Score="3" Body="&lt;p&gt;On line 3, &lt;code&gt;rain_clim=xr.open_dataset('Rainfall-'+str(i)+'.nc')&lt;/code&gt;, every time the loop iterates, &lt;code&gt;rain_clim&lt;/code&gt; gets set to the value of the current data set. Follow user arkaia's suggestion, along the lines of either &lt;code&gt;rain_clim += xr.open_dataset('My_File')&lt;/code&gt; or&lt;/p&gt;&#xA;&lt;p&gt;&lt;code&gt;rain_clim = []&lt;/code&gt; &lt;br/&gt;&#xA;&lt;code&gt;for i in range(n_flood_years):&lt;/code&gt; &lt;br/&gt;&#xA;&lt;code&gt;    tmp = xr.open_dataset(files[i])&lt;/code&gt; &lt;br/&gt;&#xA;&lt;code&gt;    rain_clim += tmp&lt;/code&gt; &lt;br/&gt;&#xA;&lt;code&gt;rain_clim = rain_clim / (i+1)  # sensitive to 0-based or 1-based indexing&lt;/code&gt;&lt;/p&gt;&#xA;&lt;p&gt;Apologies for the poor formatting&lt;/p&gt;&#xA;" OwnerUserId="30388" LastEditorUserId="30388" LastEditDate="2024-01-25T16:09:21.483" LastActivityDate="2024-01-25T16:09:21.483" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="25916" PostTypeId="2" ParentId="25880" CreationDate="2024-01-26T14:18:48.170" Score="3" Body="&lt;p&gt;The aftermath of a snowfall can also cause a cooling near the surface, if an air mass moves in that's warm enough to melt the snow. The snow indeed starts to melt, thereby absorbing the latent heat required to do so and cooling the otherwise warmer air near the surface. If, as often happens during the winter, the warmer air also brings in a dew point above 0°C/32°F, then this near-surface cooling can lead to water vapor condensation and thus induce fog.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2024-02-24T08:01:41.893" LastActivityDate="2024-02-24T08:01:41.893" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25918" PostTypeId="1" CreationDate="2024-01-26T18:54:49.623" Score="1" ViewCount="75" Body="&lt;p&gt;I am collecting every mineral of the year since 2012, and I have not found anything on last year's mineral. Thank you.&lt;/p&gt;&#xA;" OwnerUserId="30397" LastActivityDate="2024-02-26T03:10:26.203" Title="Does anyone know what the mineral of the year 2023 is?" Tags="|geochemistry|mineralogy|minerals|mining|soil-science|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25919" PostTypeId="2" ParentId="18582" CreationDate="2024-01-26T18:57:06.153" Score="2" Body="&lt;p&gt;No it is not by chance. As an ion, rare-Earth metals and compounds behave like alkaline Earth metals, so they form near each other. For example, neodymium has similar chemical properties to barium. They can both modify and cause fluorescence in calcite and/or fluorite.&lt;/p&gt;&#xA;" OwnerUserId="30397" LastEditorUserId="30397" LastEditDate="2024-01-26T18:58:40.183" LastActivityDate="2024-01-26T18:58:40.183" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25920" PostTypeId="2" ParentId="25906" CreationDate="2024-01-26T19:07:49.467" Score="5" Body="&lt;p&gt;You are on track to answering this yourself. Temperature is a continuous field, so near any surface it has to follow the boundary conditions, with the effect of any surface topography decaying away with depth.&lt;/p&gt;&#xA;&lt;p&gt;For a steady-state heat flow in a homogeneous media, the &lt;a href=&quot;https://en.wikipedia.org/wiki/Heat_equation&quot; rel=&quot;noreferrer&quot;&gt;Heat equation&lt;/a&gt; reduces to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Laplace%27s_equation&quot; rel=&quot;noreferrer&quot;&gt;Laplace Equation&lt;/a&gt;, which is easy to solve numerically. For example, here are the steady-state temperature contours for a 4 km tall square &amp;quot;mountain&amp;quot; with a 10°C surface temperature being heated from below by a 40 km deep 1000°C mantle boundary, assuming homogeneous rock.&#xA;&lt;a href=&quot;https://i.stack.imgur.com/RZkfM.jpg&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/RZkfM.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The real profile, of course, also depends on the details of the subsurface geology and history.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Different rocks have different thermal conductivities, so even if the surface is flat, changes in rock types along a transit will change the underground temperature profiles.  An example of this is the temperature dip at kilometre 135 in the Gotthard Base Tunnel that is due to porous rocks allowing cold surface water to penetrate deep underground.&lt;/li&gt;&#xA;&lt;li&gt;The time it takes for heat to diffuse into topography can be comparable to the time it takes for the topography to form, so the geological history matters as well. For example, a typical rock thermal diffusivity is &lt;span class=&quot;math-container&quot;&gt;$\kappa~\sim 1.2\times 10^{-6}\,\mathrm{m^2/s}$&lt;/span&gt;, so the thermal diffusion time (&lt;span class=&quot;math-container&quot;&gt;$d^2/\kappa$&lt;/span&gt;) into a 4 km mountain is about a half-million years.  According to &lt;a href=&quot;https://doi.org/10.1007/BF01020206&quot; rel=&quot;noreferrer&quot; title=&quot;Rybach, L., Pfister, M. Rock Mech Rock Engng 27, 77–88 (1994).&quot;&gt;&amp;quot;Temperature Predictions and Predictive Temperatures in Deep Tunnels&amp;quot;&lt;/a&gt;, the time of topology evolution in the Alps is about two million years. (This seems reasonable given their current &lt;a href=&quot;https://en.wikipedia.org/wiki/Geology_of_the_Alps#Quaternary&quot; rel=&quot;noreferrer&quot;&gt;uplift&lt;/a&gt; and &lt;a href=&quot;https://www.mic.com/impact/somehow-the-swiss-alps-are-still-growing-shocking-scientists-47686827&quot; rel=&quot;noreferrer&quot;&gt;erosion&lt;/a&gt; rates are on the order of millimetres per year.)&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="27775" LastActivityDate="2024-01-26T19:07:49.467" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25921" PostTypeId="2" ParentId="25918" CreationDate="2024-01-27T02:14:46.323" Score="0" Body="&lt;p&gt;Based on the following from &lt;a href=&quot;https://mineralogy-ima-wordpress.website/&quot; rel=&quot;nofollow noreferrer&quot;&gt;IMA&lt;/a&gt;. Their MOY  will be announced in spring:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Each spring, CNMNC is electing a “Mineral of the Year”. For 2022, this award has been assigned to lazaraskeite. The mineral was discovered in the area of Oro Valley, north of Tucson, Pima County, Arizona, USA.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;We do already have a Mineral Cup  winner from 2023: &lt;a href=&quot;https://www.mineralcup.org/bracket&quot; rel=&quot;nofollow noreferrer&quot;&gt;Zircon&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/zN5gp.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/zN5gp.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Alt text:  A 32-mineral elimination bracket for Mineral Cup 2023 with results from  matches marked, with minerals eliminated left-to-right top-to-bottom culminating in Zircon’s victory. (Retrieved 26 January 2024.)&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2024-01-27T02:14:46.323" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25924" PostTypeId="1" CreationDate="2024-01-28T15:22:13.723" Score="5" ViewCount="39" Body="&lt;p&gt;Some years ago I made a weather app based on a yearly updated Copernicus dataset.&#xA;Its main features are monthly wind roses that summarize the last 5 years for a selected area.&#xA;My idea was that this would be a nice tool for holiday or passage planning.&#xA;This &lt;a href=&quot;https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-era5-single-levels?tab=overview&quot; rel=&quot;nofollow noreferrer&quot;&gt;ERA5 hourly data on single levels&lt;/a&gt; dataset from &lt;a href=&quot;https://cds.climate.copernicus.eu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;cds.climate.copernicus.eu&lt;/a&gt; is used.&lt;/p&gt;&#xA;&lt;p&gt;What I am currently missing are the ocean currents. I saw that the dataset includes Stokes drift but unfortunately this is much lower than the ocean currents. Is there any related dataset that includes such currents? Or another dataset with a similar resolution?&lt;/p&gt;&#xA;&lt;p&gt;Currently, I am using 8 measurements per day of the previous 5 years minus 20° from the poles (70°S to 70°N).&lt;/p&gt;&#xA;" OwnerUserId="30407" LastEditorUserId="6" LastEditDate="2024-01-29T10:52:45.627" LastActivityDate="2024-01-29T10:52:45.627" Title="Are there good public datasets for ocean currents?" Tags="|ocean-currents|open-data|reanalysis|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25925" PostTypeId="1" CreationDate="2024-01-29T07:58:56.993" Score="1" ViewCount="42" Body="&lt;p&gt;I pose this question as a curious enthusiast lacking formal education in chemistry or Earth sciences. My intrigue has been kindled by various articles and discussions and while I may not be certain of the words needed to convey this, I'm hopeful that you can guide me in the right direction.&lt;/p&gt;&#xA;&lt;p&gt;My curiosity is about theories around Earth's early prehistoric atmosphere and the conditions that might have facilitated the existence of vast quantities of water in an as of yet unknown gaseous or vapor state.&lt;/p&gt;&#xA;&lt;p&gt;What types of gases and atmospheric pressures would have been requisite to maintain a substantial amount of water in the atmosphere? What specific hypothetical Earth states or conditions would be necessary to sustain it?&lt;/p&gt;&#xA;&lt;p&gt;Conversely what shifts or processes might lead to the consolidation of this &amp;quot;state&amp;quot; into downpours or bodies of liquid water and oceans?&lt;/p&gt;&#xA;&lt;p&gt;I have encountered theories suggesting that Earth's water oceans did not exist in a distant prehistory. And that the early Earth's atmosphere may have been rich in greenhouse gases like CO2 and CH4, contributing to higher temperatures and pressures than those we are familiar with today. Your guidance and insights would be appreciated. Because these questions have bothered me for a while.&lt;/p&gt;&#xA;" OwnerUserId="30410" LastEditorUserId="30410" LastEditDate="2024-01-29T08:00:59.570" LastActivityDate="2024-01-29T08:00:59.570" Title="Water and Atmospheric Conditions in Earth prehistory" Tags="|earth-history|climate-models|atmosphere-modelling|atmospheric-chemistry|precambrian|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25927" PostTypeId="1" AcceptedAnswerId="25928" CreationDate="2024-01-29T23:13:42.683" Score="7" ViewCount="4456" Body="&lt;p&gt;I was searching for the baobabs in Madagascar and found these wide circles near Avenue of the Baobabs...What are these?&lt;a href=&quot;https://i.stack.imgur.com/XHP2U.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XHP2U.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Here's the coordonates 20°16'53&amp;quot;S 44°28'49&amp;quot;E, and here is a link: &lt;a href=&quot;https://maps.app.goo.gl/PWqZ6BioBrV1sRbt7&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://maps.app.goo.gl/PWqZ6BioBrV1sRbt7&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="30413" LastEditorUserId="6298" LastEditDate="2024-02-02T20:09:48.537" LastActivityDate="2024-02-02T20:09:48.537" Title="What are these very wide circles I saw on google map in Madagascar?" Tags="|geography|satellite-oddities|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25928" PostTypeId="2" ParentId="25927" CreationDate="2024-01-30T00:22:18.777" Score="18" Body="&lt;p&gt;It's called center pivot irrigation. A long irrigation rig sprays water over a small part of a crop field to be irrigated. To cover the entire field, the irrigation rig rotates in a very large circle about a central pivot point. The result is circles such as those shown in the question. This technique is used worldwide for agriculture in semiarid areas where water is somewhat abundant but rain is not abundant (or is infrequent). Those circles are even more impressive in desert-like areas. What one sees is circles of green surrounded by brown.&lt;/p&gt;&#xA;" OwnerUserId="239" LastEditorUserId="543" LastEditDate="2024-01-30T01:17:11.743" LastActivityDate="2024-01-30T01:17:11.743" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25930" PostTypeId="1" AcceptedAnswerId="25936" CreationDate="2024-01-30T20:58:36.063" Score="3" ViewCount="89" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;On the night of 27 January 1887, a fierce winter storm dropped&#xA;snowflakes described as &amp;quot;larger than milk pans&amp;quot; over the Clark Fork&#xA;River valley, in the vicinity of a ranch owned by Matt Coleman, near&#xA;Missoula in Montana, USA. Reports suggest that they were up to 1 ft 3&#xA;in (38 cm) wide and 8 in (20 cm) thick.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Source: &lt;a href=&quot;https://www.guinnessworldrecords.com/world-records/73325-largest-snowflake&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.guinnessworldrecords.com/world-records/73325-largest-snowflake&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;That being said, its a report. And it's from 1887 with word of mouth. No pictures. Are there any documented cases of large snowflakes that are actually documented?&lt;/p&gt;&#xA;" OwnerUserId="6949" LastEditorUserId="6949" LastEditDate="2024-01-31T16:20:21.347" LastActivityDate="2024-02-01T19:28:11.873" Title="Have snowflakes (or chained snowflakes) really been documented in sizes as 'large as milk pans'?" Tags="|snow|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25931" PostTypeId="2" ParentId="14306" CreationDate="2024-01-31T07:51:41.270" Score="1" Body="&lt;p&gt;I will cite &lt;a href=&quot;https://medium.com/@wenzhao.li1989/soil-moisture-convert-mm-kg-m-2-and-m%C2%B3-m-3-e52be1fe98ef&quot; rel=&quot;nofollow noreferrer&quot;&gt;this medium post&lt;/a&gt; referring to LDAS datasets&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Many of the output fields for water amounts (e.g., precipitation, evapotranspiration, soil moisture, etc.) are given in units of &lt;span class=&quot;math-container&quot;&gt;$[kg\ m^{-2}]$&lt;/span&gt;. Many users prefer units of &lt;span class=&quot;math-container&quot;&gt;$[mm]$&lt;/span&gt;. If the assumption is made that the density of the water in the soil is 1000 &lt;span class=&quot;math-container&quot;&gt;$[kg\ m^{-3}]$&lt;/span&gt;, then the value in &lt;span class=&quot;math-container&quot;&gt;$[kg\ m^{-2}]$&lt;/span&gt; is identical to the value in &lt;span class=&quot;math-container&quot;&gt;$[mm]$&lt;/span&gt;:&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Also, the post explains some datasets present the data in&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The NCA-LDAS dataset currently provide soil moisture values in units of &lt;span class=&quot;math-container&quot;&gt;$[m^3\ m^{-3}]$&lt;/span&gt; for volumetric soil moisture. To convert to units of &lt;span class=&quot;math-container&quot;&gt;$[kg\ m^{-2}]$&lt;/span&gt; for the total soil moisture amount in each layer, all you do is multiply the &lt;span class=&quot;math-container&quot;&gt;$[m^3\ m^{-3}]$&lt;/span&gt; value by the thickness of the layer in &lt;span class=&quot;math-container&quot;&gt;$[mm]$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;So. You can divide the data by the soil depth.&lt;/p&gt;&#xA;" OwnerUserId="27672" LastActivityDate="2024-01-31T07:51:41.270" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25932" PostTypeId="1" CreationDate="2024-01-31T12:19:35.077" Score="2" ViewCount="25" Body="&lt;p&gt;I have read that alkaline rock dust added to the sea can increase algal growth and sequestration of CO2. Is this part of a natural negative feedback for global warming because a typical scenario for global warming is that warm air moves further north carrying more moisture than cooler times. We seem to be seeing this in the UK at the moment with frequent flooding and there will be associated erosion of soils. Also in mountainous areas melting glaciers expose rock and carry erosion to the sea. I am anticipating that if it is a feedback mechanism it will be too slow to deal with the rate we are adding greenhouse gases to the atmosphere, we will step over that oportunity?&lt;/p&gt;&#xA;" OwnerUserId="22160" LastActivityDate="2024-01-31T12:19:35.077" Title="Is increased erosion due to flooding part of a negative feedback mechanism for global warming?" Tags="|climate-change|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25933" PostTypeId="1" CreationDate="2024-01-31T16:01:45.453" Score="1" ViewCount="20" Body="&lt;p&gt;I wanted to ask this question as it relates to a project I am working on. In this &amp;quot;timeline&amp;quot; when India broke away from Gondwana the Indian Plate took a small piece of land from Eastern Antarctica; forming a large island located south of India. Could the break up of the tectonic plates allowed for such a landmass to exist. If so, how would it affect the oceanography of the Indian ocean with its movement? Any help would be greatly appreciated!&lt;/p&gt;&#xA;" OwnerUserId="30426" LastEditorUserId="2470" LastEditDate="2024-02-01T07:33:27.000" LastActivityDate="2024-02-01T07:33:27.000" Title="Question regarding the breakup of India from Eastern Gondwana" Tags="|geophysics|climate|oceanography|plate-tectonics|" AnswerCount="0" CommentCount="1" ClosedDate="2024-02-22T17:40:38.540" ContentLicense="CC BY-SA 4.0" />
  <row Id="25935" PostTypeId="2" ParentId="25806" CreationDate="2024-02-01T10:42:58.303" Score="1" Body="&lt;p&gt;Evaporation is neither a sufficient nor necessary conditions for rainfall to occur over a certain region.&lt;/p&gt;&#xA;&lt;p&gt;First of all, due to moisture being &amp;quot;moved around&amp;quot; by atmospheric motions, even when rainfall does occur, nothing guarantees you that the droplets falling in that area are made by moisture that was evaporated from the same area. There are many old studies (Budyko) quantifying the ratio of &amp;quot;moisture recycling&amp;quot; and, in general, one can see that the majority of moisture causing rainfall is advected from other areas which could be hundreds (if not thousands) of kilometers away.&lt;/p&gt;&#xA;&lt;p&gt;Second, and most importantly, as someone already said in the comments, evaporation contributes locally to increase the concentration of water vapour in the atmosphere. However, for rainfall to occur you need many different conditions to be satisfied. There are many dynamical or thermodynamical processes that lead to condensation of water vapour into suspended droplets (clouds) which can then grow and form rainfall. Adding water vapour to the atmosphere locally has a negligible effect in most cases, as it can only change the atmospheric profile close to the surface.&lt;/p&gt;&#xA;&lt;p&gt;The question still touches an interesting subject, because there are many studies looking at soil moisture-precipitation interaction which suggest that, in some limited cases, more evaporation could lead, in cases where rainfall is triggered by some external factors, to higher rainfall totals. In other words, a wetter soil could lead to more rainfall than a dry soil. However, this only happens in small to nonexistent synoptic forcing, so it is something that you almost never observe in reality. In fact, as soon as you have some wetter/drier patch, mesoscale circulations similar to land-sea breezes form and advect the moist air somewhere else.&lt;/p&gt;&#xA;" OwnerUserId="27107" LastActivityDate="2024-02-01T10:42:58.303" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25936" PostTypeId="2" ParentId="25930" CreationDate="2024-02-01T19:28:11.873" Score="2" Body="&lt;p&gt;Large aggregate snowflakes an inch or so across formed from dendritic ice crystals sticking together are not uncommon, and according to research summarized by the New York Times, &lt;a href=&quot;https://www.nytimes.com/2007/03/20/science/20snow.html&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;William J. Broad, New York Times, 20 March 2007&quot;&gt;&amp;quot;Snowflakes as Big as Frisbees?&amp;quot;&lt;/a&gt; may be extremely unlikely but not impossible.&lt;/p&gt;&#xA;&lt;p&gt;Larger aggregates &lt;a href=&quot;https://www.research-collection.ethz.ch/handle/20.500.11850/144352&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;Fall Velocity and Shape of Snowflakes, Monika Hanesch, Ph.D. Thesis, 1999, Swiss Federal Institute of Technology, Figure 6.1&quot;&gt;fall faster&lt;/a&gt;, so as they fall they will sweep out and agglomerate smaller snowflakes, growing ever larger until broken up by wind or they land. To get the largest aggregates, one needs temperatures around freezing so the snowflakes are sticky, a very large density of snowflakes, and relatively still air. There is no simple theoretical upper limit on their size.&lt;/p&gt;&#xA;&lt;p&gt;The Montana report is definitely sketchy, but William Pike's 1988 article on &lt;a href=&quot;http://www.ijmet.org/wp-content/uploads/2014/09/125.pdf&quot; rel=&quot;nofollow noreferrer&quot; title=&quot;W.S. Pike, Journal of Meteorology, UK, January 1988, Vol. 13, No. 125, pages 3-16&quot;&gt;&amp;quot;Unusually-Large Snowflakes&amp;quot;&lt;/a&gt; noted that there are reports from &amp;quot;reliable observers&amp;quot; of 2-6 inch diameter aggregate snowflakes. (Pike was inspired to do the research after he observed 2-3 inch snowflakes himself in Vancouver, Canada.)&lt;/p&gt;&#xA;&lt;p&gt;As noted in the New York Times article, the problem with both forming and documenting large snowflakes is that they are so fragile. Large aggregates are weakly bound, can be easily broken by air movements, and disappear on landing.  This can be contrasted with large hailstones which can be very robust, so they stick around after landing and are easily photographed. Large snowflakes need to be imaged as they fall.&lt;/p&gt;&#xA;&lt;p&gt;There are lots of videos online showing 1-2 inch aggregates falling. Interestingly, some of the best (such as &lt;a href=&quot;https://youtu.be/adpOXRsUVz0?si=OkXqhIxNoxIZIz6G&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; or &lt;a href=&quot;https://www.facebook.com/viralhog/videos/285993029403702/&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt;) do come from Montana. The apparent lack of videos or images of larger aggregate snowflakes shows that they are clearly very rare.&lt;/p&gt;&#xA;" OwnerUserId="27775" LastActivityDate="2024-02-01T19:28:11.873" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25938" PostTypeId="2" ParentId="24151" CreationDate="2024-02-02T01:49:18.950" Score="1" Body="&lt;p&gt;Natural carbon sedimentation rates are - compared to fossil fuel emissions - very low, around 1/1000th, therefore must be increased a thousand fold to send enough Carbon to sediments to compensate for emissions. Ocean fertilization does not automatically lead to greater sedimentation as the organisms that benefit become part of the greater ocean food chain. Some increase in ocean biomass may use some of the CO2 that is dissolved in oceans but it is not clear how ocean biology will respond,  nor how such an increase would become irreversible.&lt;/p&gt;&#xA;&lt;p&gt;Note the relative amounts - 9.3 Petagrams per year (2017) of FF emissions versus 0.01 Petagrams of Burial to Sediments -&#xA;&lt;a href=&quot;https://i.stack.imgur.com/oLYCa.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oLYCa.jpg&quot; alt=&quot;The Carbon Cycle&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Reducing emissions by building an abundance of low emissions energy appears to be the most effective - and cost effective - way to mitigate global warming.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2024-02-02T01:49:18.950" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25939" PostTypeId="1" CreationDate="2024-02-03T01:46:16.080" Score="1" ViewCount="17" Body="&lt;p&gt;I am trying to make sense as to why salinity levels impact the density of ocean water more than temperature. This is in an attempt to understand the two-box model of ocean circulation.&lt;/p&gt;&#xA;&lt;p&gt;I know there are graphs/data available that show the salinity levels vs density of water, as well as graphs that show temperature vs the density of water. However, in order for these to make more sense in terms of why salinity makes more of a difference in determining the density, I wanted to understand first what are the lowest and highest salinity levels/temperature of ocean water in the Atlantic Meridional Overturning Circulation (AMOC).&lt;/p&gt;&#xA;&lt;p&gt;I realize this is a bit of a simplification. However, in the density calculations, salinity holds more weight than temperature in determining the density of the ocean water. I just want to have a concrete way (even if it's oversimplified for the sake of a mathematics exercise) to understand why salinity has a greater effect.&lt;/p&gt;&#xA;&lt;p&gt;Thank you!!!&lt;/p&gt;&#xA;" OwnerUserId="30438" LastActivityDate="2024-02-03T01:46:16.080" Title="What are realistic salinity level ranges (in psu) and temperature ranges (in celsius) of the North Atlantic Ocean?" Tags="|oceanography|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25940" PostTypeId="1" AcceptedAnswerId="25942" CreationDate="2024-02-03T02:46:42.600" Score="2" ViewCount="70" Body="&lt;p&gt;I have a question about &lt;a href=&quot;https://serc.carleton.edu/integrate/teaching_materials/earth_modeling/student_materials/unit8_article1.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;a module on Stommel's Two-Box model&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I am uncertain about the following density equation:&#xA;&lt;span class=&quot;math-container&quot;&gt;$ \Delta  \rho =  | R \Delta S - \Delta T| $&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;A larger difference between temperatures/salinity levels across the two regions of the North Atlantic should both increase the density difference. Why is this a subtraction? Is this because of the opposite relationship between salinity/temperature at each pole (i.e., high salinity increasing the density at the equatorial region with high temp decreasing density at the equatorial region, and vice versa at the poles)?&lt;/p&gt;&#xA;" OwnerUserId="30438" LastActivityDate="2024-02-04T23:16:16.017" Title="Questions about Stommel's Two-Box Model (North Atlantic Current)" Tags="|oceanography|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25941" PostTypeId="1" CreationDate="2024-02-03T11:31:54.947" Score="2" ViewCount="65" Body="&lt;p&gt;I am working on the &lt;a href=&quot;https://cds.climate.copernicus.eu/cdsapp#!/dataset/reanalysis-oras5?tab=overview&quot; rel=&quot;nofollow noreferrer&quot;&gt;ORAS5&lt;/a&gt; dataset which comes as an archive of netCDF files. Currently, I am using python and &lt;a href=&quot;https://unidata.github.io/netcdf4-python&quot; rel=&quot;nofollow noreferrer&quot;&gt;netcdf4&lt;/a&gt; to process it.&lt;/p&gt;&#xA;&lt;p&gt;My goal is to get surface level ocean currents across the globe (almost, 70°N to 70°S).&#xA;The dataset itself has several variables.&#xA;These are relevant for my problem:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;depth&lt;/strong&gt; 1D (75,) array describing increasing depths&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;lat&lt;/strong&gt; 2D (1021, 1442) array describing latitude&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;lon&lt;/strong&gt; 2D (1021, 1442) array describing longitude&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;vozocrte/vomecrtn&lt;/strong&gt; 3D (75, 1021, 1442) array describing zonal or meridional velocity&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Currently, I am creating a lat-lon grid with desired resolution and then loop over this grid to extract &lt;code&gt;vozocrte&lt;/code&gt; or &lt;code&gt;vomecrtn&lt;/code&gt;.&#xA;In principle it looks like this:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import numpy as np&#xA;from netCDF4 import Dataset&#xA;&#xA;def mask_map(vals: np.ndarray, range: tuple[int, int], res=0.25) -&amp;gt; dict[float, np.ndarray]:&#xA;    return {&#xA;        d: (vals &amp;gt;= d - res / 2) &amp;amp; (vals &amp;lt;= d + res / 2)&#xA;        for d in np.arange(range[0], range[1] + res, res)&#xA;    }&#xA;&#xA;ds = Dataset(file, &amp;quot;r&amp;quot;, format=&amp;quot;NETCDF4&amp;quot;)&#xA;depths = ds.variables[&amp;quot;depth&amp;quot;][:]  # (75,) depth in m&#xA;lats = ds.variables[&amp;quot;nav_lat&amp;quot;][:]  # (1021, 1442) lat in degrees&#xA;lons = ds.variables[&amp;quot;nav_lon&amp;quot;][:]  # (1021, 1442) lon in degrees&#xA;vals = ds.variables[&amp;quot;vozocrte&amp;quot;][:]  # (76, 1021, 1442) in m/s&#xA;vals = vals[0, depths &amp;lt; 5]&#xA;lon_2_mask = mask_map(vals=lons, range=lon_range)&#xA;lat_2_mask = mask_map(vals=lats, range=lat_range)&#xA;&#xA;records = []&#xA;for lon, lons_mask in lon_2_mask.items():&#xA;    for lat, lats_mask in lat_2_mask.items():&#xA;        masked = vals[..., lats_mask &amp;amp; lons_mask]&#xA;        if not masked.mask.all():&#xA;            records.append({&amp;quot;component&amp;quot;: masked.mean(), &amp;quot;lat&amp;quot;: lat, &amp;quot;lon&amp;quot;: lon})&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;It works but it is very slow.&lt;/p&gt;&#xA;&lt;p&gt;I am unfamiliar with this type of dataset (mapping depth-lon-lat to z-y-x, then using z-y-x to get some values).&#xA;Is there a more efficient way of doing this?&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Edit&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I realized I should explain the data better.&#xA;The variables &lt;code&gt;depth&lt;/code&gt;, &lt;code&gt;nav_lat&lt;/code&gt;, &lt;code&gt;nav_lon&lt;/code&gt;, &lt;code&gt;vozocrte&lt;/code&gt;/&lt;code&gt;vomecrtn&lt;/code&gt; mentioned above all contain masked numpy arrays of different shape.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;code&gt;vozocrte&lt;/code&gt;/&lt;code&gt;vomecrtn&lt;/code&gt; describe a velocity in m/s as &lt;code&gt;velocity(z, y, x)&lt;/code&gt;.&lt;/li&gt;&#xA;&lt;li&gt;&lt;code&gt;depth&lt;/code&gt; describes depth in m as &lt;code&gt;depth(z)&lt;/code&gt;.&lt;/li&gt;&#xA;&lt;li&gt;&lt;code&gt;nav_lon&lt;/code&gt; describes longitude in degree as &lt;code&gt;longitude(y, x)&lt;/code&gt;.&lt;/li&gt;&#xA;&lt;li&gt;&lt;code&gt;nav_lat&lt;/code&gt; describes latitude in degree as &lt;code&gt;latitude(y, x)&lt;/code&gt;.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;em&gt;E.g.&lt;/em&gt; &lt;code&gt;nav_lat&lt;/code&gt; can contain a masked array of &lt;code&gt;[[87.021, 86.721, 86.101, ...], ...]&lt;/code&gt;.&#xA;And &lt;code&gt;nav_lon&lt;/code&gt; can contain a masked array of &lt;code&gt;[[178.131, 177.809, 176.980, ...], ...]&lt;/code&gt;.&#xA;&lt;code&gt;depth&lt;/code&gt; a masked array of &lt;em&gt;e.g.&lt;/em&gt; &lt;code&gt;[0.023, 1.201, ...]&lt;/code&gt;.&lt;/p&gt;&#xA;&lt;p&gt;My naive approach above follows the logic of first getting a mask for &lt;code&gt;z, y, x&lt;/code&gt; from the variables depth, nav_lat, nav_lon, then using them to get velocities.&#xA;&lt;em&gt;E.g.&lt;/em&gt; if I wanted 10°-11°N, 15°-16°E, less than 5m deep:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;depth_mask = depths &amp;lt; 5&#xA;lon_mask = (lons &amp;gt;= 15) &amp;amp; (lons &amp;lt; 16)&#xA;lat_mask = (lats &amp;gt;= 10) &amp;amp; (lats &amp;lt; 11)&#xA;vals[depth_mask, ..., lon_mask &amp;amp; lat_mask]&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="30407" LastEditorUserId="30407" LastEditDate="2024-02-05T16:36:52.457" LastActivityDate="2024-02-05T16:36:52.457" Title="Efficient way to parse lat-lon grid at certain depth in tripolar model from nc file?" Tags="|ocean-currents|python|netcdf|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25942" PostTypeId="2" ParentId="25940" CreationDate="2024-02-03T11:46:00.440" Score="1" Body="&lt;p&gt;Modifiing my previous answer thanks to you comment, I realized I not clear at all. Here it's better.&lt;/p&gt;&#xA;&lt;p&gt;First, I want to state that the notations in your material seem weird to me as the normalizing and adimentionnality of the values are not properly presented. For the eq. 1 and 2, &lt;span class=&quot;math-container&quot;&gt;$T_{eq}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$S_{eq}$&lt;/span&gt; are said to be dimensionless yet they are added to &lt;span class=&quot;math-container&quot;&gt;$\Delta T$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\Delta S$&lt;/span&gt; that are not introduced as dimensionless.&lt;/p&gt;&#xA;&lt;p&gt;In any case, it seems akin to the &lt;em&gt;density anomaly&lt;/em&gt; (see &lt;a href=&quot;https://scholarship.claremont.edu/cgi/viewcontent.cgi?article=1040&amp;amp;context=codee&quot; rel=&quot;nofollow noreferrer&quot;&gt;THIS LINK&lt;/a&gt;, page 6). The same pdf file the link leads to bears a thorough explanation of the model (page 9 and following).&lt;/p&gt;&#xA;&lt;p&gt;Without going trough the nondimensionalization process, by taking the density equation of salty waters, &lt;span class=&quot;math-container&quot;&gt;$\rho=\rho_0(1-\alpha T+\beta S)$&lt;/span&gt; (increases with increasing S and decreases with increasing T with rate respectively &lt;span class=&quot;math-container&quot;&gt;$\alpha$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\beta$&lt;/span&gt;), you have that &lt;span class=&quot;math-container&quot;&gt;\begin{align}\Delta \rho&amp;amp;=\rho_{A}-\rho_{B}\\&amp;amp;=\rho_0(1-\alpha T_{A}+\beta S_{A})-\rho_0(1-\alpha T_{B}+\beta S_{B})\\&amp;amp;=\rho_0(-\alpha \Delta T+\beta \Delta S).\end{align}&lt;/span&gt; Using &lt;span class=&quot;math-container&quot;&gt;$R=\frac{\beta}{\alpha}$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\Delta \rho_*=\frac{\Delta \rho}{\alpha\rho_0}$&lt;/span&gt; leads to &lt;span class=&quot;math-container&quot;&gt;$$\Delta\rho_*=-\Delta T+R\Delta S.$$&lt;/span&gt; I'm not sure about why the absolute value is introduced, maybe because the textbook authors weren't interested in wich part of the ocean was the most dense?&lt;/p&gt;&#xA;&lt;p&gt;You can take a look at the original paper by Stommel at he following &lt;a href=&quot;https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.2153-3490.1961.tb00079.x&quot; rel=&quot;nofollow noreferrer&quot;&gt;LINK&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="21235" LastEditorUserId="21235" LastEditDate="2024-02-04T23:16:16.017" LastActivityDate="2024-02-04T23:16:16.017" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25943" PostTypeId="1" CreationDate="2024-02-03T14:25:16.093" Score="2" ViewCount="100" Body="&lt;p&gt;To see Hawaii from Texas how high in altitude would you have to be?  I know the curvature of the earth has a big role in this&lt;/p&gt;&#xA;" OwnerUserId="30441" LastActivityDate="2024-02-07T13:50:17.657" Title="What is the line of sight altitude to see hawaii from texas" Tags="|geography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25944" PostTypeId="2" ParentId="25943" CreationDate="2024-02-03T22:11:34.303" Score="6" Body="&lt;p&gt;TL;DR: It depends on what one means by Hawaii, what one means by Texas, and whether one is concerned with atmospheric effects. The answer is somewhere between less than 2400 km and over 12600 km.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;A note regarding the edit&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;This answer is a significant change from the previous answer where I focused solely on Honolulu and El Paso. I also made a mistake in that previous version of the answer; I used the longitude of El Paso where I should have used its latitude.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Assumptions&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;I'll be&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Assuming a spherical Earth with a radius of 6371 km&lt;/li&gt;&#xA;&lt;li&gt;Completely ignoring atmospheric effects&lt;/li&gt;&#xA;&lt;li&gt;Assuming &amp;quot;seeing&amp;quot; means the altitude at which the point in question is barely visible on the limb of the Earth as seen from that altitude.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;strong&gt;Locations&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;The Hawaiian Archipelago is a very long chain of islands, stretching from Hawaii Island to Kure Atoll.I'll be using the following locations in the Hawaii Archipelago :&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th&gt;Location&lt;/th&gt;&#xA;&lt;th&gt;Coordinates&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Mauna Kea&lt;/td&gt;&#xA;&lt;td&gt;19°49'14.4&amp;quot;N 155°28'5.0&amp;quot;W&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Honolulu&lt;/td&gt;&#xA;&lt;td&gt;21°18'25&amp;quot;N 157°51'30&amp;quot;W&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Ni'ihau&lt;/td&gt;&#xA;&lt;td&gt;21°54'0&amp;quot;N 160°10'0&amp;quot;W&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Midway Atoll&lt;/td&gt;&#xA;&lt;td&gt;28°12'27&amp;quot;N 177°21'0&amp;quot;W&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Kure Atoll&lt;/td&gt;&#xA;&lt;td&gt;28°25'0&amp;quot;N 178°20'0&amp;quot;W&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;&#xA;&lt;p&gt;The peak of Mauna Kea on Hawaii Island is about 4.2 km above sea level. I'll be using that elevation for Mauna Kea; for all other locations I'll be using sea level.&lt;/p&gt;&#xA;&lt;p&gt;I'll be using the following locations in Texas:&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th&gt;Location&lt;/th&gt;&#xA;&lt;th&gt;Coordinates&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;El Paso&lt;/td&gt;&#xA;&lt;td&gt;31°45'33&amp;quot;N 106°29'19&amp;quot;W&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Sweetwater&lt;/td&gt;&#xA;&lt;td&gt;32°28'5&amp;quot;N 100°24'26&amp;quot;W&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Texarkana&lt;/td&gt;&#xA;&lt;td&gt;33°26'14&amp;quot;N 94°4'3&amp;quot;W&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;&#xA;&lt;p&gt;EL Paso is about as far west as one can get in Texas; it's closer to Los Angeles than it is to Texarkana. I'm guessing Texarkana is the furthest location in Texas from the Hawaiian islands. Sweetwater is about halfway between El Paso and Texarkana.&lt;/p&gt;&#xA;&lt;p&gt;The elevation of the Texas locales is irrelevant as I'll be reporting height above sea level (height above 6371 km).&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Mathematics&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;&amp;quot;Barely seeing&amp;quot; a point at sea level from another point at elevation requires calculating the angular separation between the two points via&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$\cos\theta = \sin\phi_1\sin\phi_2 + \cos\phi_1\cos\phi_2\cos(\lambda_1-\lambda_2) \tag{1}$$&lt;/span&gt;&#xA;where &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; is the angular separation, &lt;span class=&quot;math-container&quot;&gt;$\phi_1$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\phi_2$&lt;/span&gt; are the latitudes of the two points, and &lt;span class=&quot;math-container&quot;&gt;$\lambda_1$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\lambda_2$&lt;/span&gt; are the longitudes of the two points.&lt;/p&gt;&#xA;&lt;p&gt;Since we're just barely seeing the point in Hawaii, the angle between the line segment from the center of the Earth to the point in Hawaii and the line segment from the point in Hawaii to the observation point (the point above the location in Texas) is 90°. This makes the triangle formed by the center of the Earth, the point in Hawaii, and the observation point a right triangle&lt;/p&gt;&#xA;&lt;p&gt;Denoting &lt;span class=&quot;math-container&quot;&gt;$R=6371~\text{km}$&lt;/span&gt; as the radius of the spherical Earth, &lt;span class=&quot;math-container&quot;&gt;$h$&lt;/span&gt; as the height above sea level the Earth at the point in question, and &lt;span class=&quot;math-container&quot;&gt;$\theta$&lt;/span&gt; as calculated via equation (1), this means &lt;span class=&quot;math-container&quot;&gt;$$\cos\theta = \frac R{R+h} \tag{2}$$&lt;/span&gt; or&#xA;&lt;span class=&quot;math-container&quot;&gt;$$h = R\left(\frac1{\cos\theta}-1\right) \tag{3}$$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;For locations in Hawaii at sea level (all but Mauna Kea), equations (1) and (3) suffice to find the requisite altitude. A couple of extra steps are needed for Mauna Kea: Use equation (2) to the angular separation at which a point 4.2 km above sea level just becomes visible from sea level. (The answer is 2.0799° with the spherical Earth assumption, which corresponds to about 231.2 km on the surface of the Earth.) This reduces the altitude at the Texas site as all that is needed to be able to see that point at sea level.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Results&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;The following table portrays the angular separation between the points in Hawaii and the points in Texas (first line in each table cell) and the altitude above sea level for the point in Texas needed to barely see the point in Hawaii (the second line in each cell). For Mauna Kea, the table also reports in parentheses the reduced angular distance (the angular distance via equation (1) less 2.0799°).&lt;/p&gt;&#xA;&lt;div class=&quot;s-table-container&quot;&gt;&#xA;&lt;table class=&quot;s-table&quot;&gt;&#xA;&lt;thead&gt;&#xA;&lt;tr&gt;&#xA;&lt;th&gt;&lt;/th&gt;&#xA;&lt;th&gt;El Paso&lt;/th&gt;&#xA;&lt;th&gt;Sweetwater&lt;/th&gt;&#xA;&lt;th&gt;Texarkana&lt;/th&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/thead&gt;&#xA;&lt;tbody&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Mauna Kea&lt;/td&gt;&#xA;&lt;td&gt;45.294° (43.214°)&lt;br&gt;2371 km&lt;/td&gt;&#xA;&lt;td&gt;50.462° (48.382°)&lt;br&gt;3222 km&lt;/td&gt;&#xA;&lt;td&gt;55.762° (53.682°)&lt;br&gt;4386 km&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Honolulu&lt;/td&gt;&#xA;&lt;td&gt;46.702°&lt;br&gt;2919 km&lt;/td&gt;&#xA;&lt;td&gt;51.833°&lt;br&gt;3939 km&lt;/td&gt;&#xA;&lt;td&gt;57.072°&lt;br&gt; 5349 km&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Niʻihau&lt;/td&gt;&#xA;&lt;td&gt;48.424°&lt;br&gt;3230 km&lt;/td&gt;&#xA;&lt;td&gt;53.525°&lt;br&gt;4346 km&lt;/td&gt;&#xA;&lt;td&gt;58.720°&lt;br&gt;5899 km&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Midway Atoll&lt;/td&gt;&#xA;&lt;td&gt;60.367°&lt;br&gt;6514 km&lt;/td&gt;&#xA;&lt;td&gt;65.057°&lt;br&gt;8736 km&lt;/td&gt;&#xA;&lt;td&gt;69.728°&lt;br&gt;12017 km&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;tr&gt;&#xA;&lt;td&gt;Kure Atoll&lt;/td&gt;&#xA;&lt;td&gt;61.086°&lt;br&gt;6806 km&lt;/td&gt;&#xA;&lt;td&gt;65.752°&lt;br&gt;9142 km&lt;/td&gt;&#xA;&lt;td&gt;70.394°&lt;br&gt;12616 km&lt;/td&gt;&#xA;&lt;/tr&gt;&#xA;&lt;/tbody&gt;&#xA;&lt;/table&gt;&#xA;&lt;/div&gt;" OwnerUserId="239" LastEditorUserId="239" LastEditDate="2024-02-07T13:50:17.657" LastActivityDate="2024-02-07T13:50:17.657" CommentCount="6" ContentLicense="CC BY-SA 4.0" />
  <row Id="25949" PostTypeId="2" ParentId="25941" CreationDate="2024-02-05T13:26:04.680" Score="3" Body="&lt;p&gt;First of all: &lt;strong&gt;NEVER, EVER, EVER&lt;/strong&gt; (I repeat, &lt;strong&gt;EVER&lt;/strong&gt;) loop in &lt;code&gt;Python&lt;/code&gt; over an array to subset some values :)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://docs.xarray.dev/en/latest/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;xarray&lt;/a&gt; was created exactly to avoid having to write something like this by exploiting the native coordinates/dimensions indexing. For a brief introduction on how to subset an array&lt;/p&gt;&#xA;&lt;p&gt;List item&lt;/p&gt;&#xA;&lt;p&gt;have a look &lt;a href=&quot;https://docs.xarray.dev/en/latest/user-guide/indexing.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Regarding your specific issue, it is not clear what you are trying to achieve because you don't state what you want to &amp;quot;extract&amp;quot; in the description. Judging from the code, it seems you're trying to downsample the grid to a specific resolution (&lt;code&gt;res&lt;/code&gt;). In pure &lt;code&gt;xarray&lt;/code&gt; going from e.g. 0.25 to 0.5 degrees resolution would be as simple as doing&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import xarray as xr&#xA;&#xA;ds = xr.open_dataset(&amp;quot;test.nc&amp;quot;)&#xA;&#xA;ds.sel(lon=ds.lon[::2], lat=ds.lat[::2])&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;There are many other ways of subsetting data to extract a single point or set of points using the &lt;code&gt;sel&lt;/code&gt; operator, for example&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;ds.sel(lon=43, lat=0, method='nearest') # single point&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;There are many functions that are written to do operations on geospatial multi-dimensional arrays (interpolation, subsetting,...). As a general rule of thumb, if you're writing your own low-level function to access element one by one in Python...you're doing it wrong :D There's almost surely another function that does that in a vectorized way!&lt;/p&gt;&#xA;&lt;p&gt;Please take some time to learn how to use &lt;code&gt;xarray&lt;/code&gt; to work with Netcdf files and subset data, you'll save a lot of time in the future!&lt;/p&gt;&#xA;&lt;p&gt;P.S. Even when using &lt;code&gt;xarray&lt;/code&gt;, &lt;code&gt;Python&lt;/code&gt; remains quite slow with large dataset. If you need to do operations on large files I'd suggest you to pre-process the file BEFORE loading it into &lt;code&gt;Python&lt;/code&gt; using something like &lt;a href=&quot;https://code.mpimet.mpg.de/projects/cdo&quot; rel=&quot;nofollow noreferrer&quot;&gt;CDO&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="27107" LastActivityDate="2024-02-05T13:26:04.680" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25950" PostTypeId="2" ParentId="25941" CreationDate="2024-02-05T14:38:38.480" Score="0" Body="&lt;p&gt;There is a very simple way to do this.&#xA;The point here is that these arrays are all ordered consistently.&#xA;The dataset needs only to be subset by depth if all &lt;code&gt;lon,lat&lt;/code&gt; pairs should be extracted.&#xA;Lat and lon values can still be corrected later on to create a specific resolution.&lt;/p&gt;&#xA;&lt;p&gt;What I ended up doing is in essence this:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import numpy as np&#xA;import pandas as pd&#xA;from netCDF4 import Dataset&#xA;&#xA;&#xA;def _rm_mask(masked: np.ma.MaskedArray, fill=np.nan) -&amp;gt; np.ndarray:&#xA;    return np.where(masked.mask, fill, masked.data).astype(masked.dtype)&#xA;&#xA;&#xA;def _digitize(df: pd.DataFrame, var: str, interval: tuple[float, float], res: float):&#xA;    for target in np.arange(interval[0], interval[1] + res, res):&#xA;        mask = (df[var] &amp;gt;= target - res / 2) &amp;amp; (df[var] &amp;lt; target + res / 2)&#xA;        df.loc[mask, var] = target&#xA;&#xA;&#xA;ds = Dataset(file, &amp;quot;r&amp;quot;, format=&amp;quot;NETCDF4&amp;quot;)&#xA;depths = _rm_mask(ds.variables[&amp;quot;depth&amp;quot;][:])  # (75,) depth in m&#xA;lats = _rm_mask(ds.variables[&amp;quot;nav_lat&amp;quot;][:])  # (1021, 1442) lat in degrees&#xA;lons = _rm_mask(ds.variables[&amp;quot;nav_lon&amp;quot;][:])  # (1021, 1442) lon in degrees&#xA;vals = _rm_mask(ds.variables[&amp;quot;vozocrte&amp;quot;][:])  # (76, 1021, 1442) in m/s&#xA;vals = vals[0, depths &amp;lt; 5]&#xA;&#xA;dfdict = {&amp;quot;lat&amp;quot;: lats.flatten().tolist(), &amp;quot;lon&amp;quot;: lons.flatten().tolist()}&#xA;for layer_i in range(vals.shape[0]):&#xA;    dfdict[f&amp;quot;l{layer_i}&amp;quot;] = vals[layer_i].flatten().tolist()&#xA;&#xA;df = pd.DataFrame(dfdict)&#xA;_digitize(df=df, var=&amp;quot;lon&amp;quot;, interval=(-180, 180), res=0.25)&#xA;_digitize(df=df, var=&amp;quot;lat&amp;quot;, interval=(-70, 70), res=0.25)&#xA;df = df.groupby([&amp;quot;lon&amp;quot;, &amp;quot;lat&amp;quot;]).mean()&#xA;df.sort_index(inplace=True)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Here, most heavy lifting is done by numpy and is multithreaded.&#xA;&lt;code&gt;_digitize&lt;/code&gt; can also be written using &lt;a href=&quot;https://numpy.org/doc/stable/reference/generated/numpy.digitize.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;np.digitize&lt;/a&gt; but it looks a bit confusing (mapping to bin indices) and doesn't make such a huge difference.&#xA;Overall this computes ~36 times faster (now just a few seconds).&lt;/p&gt;&#xA;&lt;p&gt;However, as Droid mentioned &lt;a href=&quot;https://docs.xarray.dev/en/latest/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;xarray&lt;/a&gt; might be even faster.&lt;/p&gt;&#xA;" OwnerUserId="30407" LastActivityDate="2024-02-05T14:38:38.480" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25951" PostTypeId="2" ParentId="5018" CreationDate="2024-02-05T16:48:17.553" Score="1" Body="&lt;p&gt;According to the United Nations Framework Convention to Combat Climate Change (UNFCCC)&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;“Reservoir” means a component or components of the climate system where a&#xA;greenhouse gas or a precursor of a greenhouse gas is stored.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;“Sink” means any process, activity or mechanism which removes a greenhouse gas, an aerosol or a precursor of a greenhouse gas from the atmosphere.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="30447" LastActivityDate="2024-02-05T16:48:17.553" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25953" PostTypeId="1" AcceptedAnswerId="25996" CreationDate="2024-02-06T12:34:29.720" Score="2" ViewCount="47" Body="&lt;p&gt;There is subduction-related arc magmatism, such as the Andes, Indonesia, New Zealand, and elsewhere. In the same tectonic environment there's post-collisional extension magmatism such as in New Zealand.&lt;/p&gt;&#xA;&lt;p&gt;What properties differ between these two kinds of magmatism?&lt;/p&gt;&#xA;&lt;p&gt;For example Taupo Volcanic Zone is a Quaternary back arc spreading zone. A coinciding place with arc magmatism&#xA;Here is a paper relating the subject.&#xA;Wright, I. C. (1992). Shallow structure and active tectonism of an offshore continental back-arc spreading system: the Taupo Volcanic Zone, New Zealand. Marine geology, 103(1-3), 287-309.&lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="15195" LastEditDate="2024-02-07T11:29:20.307" LastActivityDate="2024-02-23T00:30:59.223" Title="Is there any diferrence between arc magmatism and post-collisional extension magmatism?" Tags="|subduction|magmatism|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25954" PostTypeId="1" CreationDate="2024-02-07T08:14:28.283" Score="1" ViewCount="23" Body="&lt;p&gt;I want to learn where the youngest subduction is in the world.   Where is the most recently started subduction zone? (The most recent place on Earth that arc magmatism has started)&lt;/p&gt;&#xA;&lt;p&gt;And the oldest subduction zone?&lt;/p&gt;&#xA;&lt;p&gt;Is the dip of the subducting slab proportional to the age of subduction?&lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="6298" LastEditDate="2024-02-07T09:13:57.117" LastActivityDate="2024-02-07T09:13:57.117" Title="Where are the youngest and oldest subduction zones in the world? Is the dip of the subducting slab proportional with the age of subduction?" Tags="|tectonics|subduction|magmatism|plate|arc|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25955" PostTypeId="2" ParentId="10128" CreationDate="2024-02-07T10:07:52.623" Score="0" Body="&lt;p&gt;Gerrit wrote:&#xA;&amp;quot;Stefan-Beltzmann and Kirchhoff laws apply always, everything radiates, including convecting gases&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;Incorrect.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.imgur.com/QErszYW.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://i.imgur.com/QErszYW.gif&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Idealized blackbody objects &amp;gt; 0 K emit at all times, whereas graybody objects &amp;gt; 0 K above their ambient emit. That's why the S-B equation in graybody form includes the temperature of the cooler object.&lt;/p&gt;&#xA;&lt;p&gt;In reality, what is happening with the S-B equation (the form meant to be used with graybody objects) is a subtraction of the energy density of the cooler object from the energy density of the warmer object to arrive at the energy density gradient; the radiant exitance of the warmer object predicated upon the energy density gradient.&lt;/p&gt;&#xA;&lt;p&gt;Idealized Blackbody Object (assumes emission to 0 K and ε = 1 by definition):&lt;/p&gt;&#xA;&lt;p&gt;q_bb = ε σ (T_h^4 - T_c^4) A_h&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt; = 1 σ (T_h^4 - 0 K) 1 m^2&#xA;&#xA; =    σ  T^4&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Graybody Object (assumes emission to &amp;gt; 0 K and ε &amp;lt; 1):&lt;/p&gt;&#xA;&lt;p&gt;q_gb = ε σ (T_h^4 - T_c^4) A_h&lt;/p&gt;&#xA;&lt;p&gt;The 'A_h' term is merely a multiplier, used if one is calculating for an area larger than unity [for instance: &amp;gt;1 m^2], which converts the result from radiant exitance (W m-2, radiant flux per unit area) to radiant flux (W).&lt;/p&gt;&#xA;&lt;p&gt;Temperature is equal to the fourth root of radiation energy density divided by Stefan's Constant (ie: the radiation constant).&lt;/p&gt;&#xA;&lt;p&gt;e = T^4 a&lt;/p&gt;&#xA;&lt;p&gt;a = 4σ/c&lt;/p&gt;&#xA;&lt;p&gt;e = T^4 4σ/c&lt;/p&gt;&#xA;&lt;p&gt;T^4 = e/(4σ/c)&lt;/p&gt;&#xA;&lt;p&gt;T = 4^√(e/(4σ/c))&lt;/p&gt;&#xA;&lt;p&gt;T = 4^√(e/a)&lt;/p&gt;&#xA;&lt;p&gt;q = ε σ (T_h^4 – T_c^4)&lt;/p&gt;&#xA;&lt;p&gt;∴ q = ε σ ((e_h / (4σ / c)) – (e_c / (4σ / c))) A_h&lt;/p&gt;&#xA;&lt;p&gt;Canceling units, we get J sec-1 m-2, which is W m-2 (1 J sec-1 = 1 W).&lt;/p&gt;&#xA;&lt;p&gt;W m-2 = W m-2 K-4 * (Δ(J m-3 / (W m-2 K-4 / m sec-1)))&lt;/p&gt;&#xA;&lt;p&gt;∴ q = (ε c (e_h - e_c)) / 4&lt;/p&gt;&#xA;&lt;p&gt;Canceling units, we get J sec-1 m-2, which is W m-2 (1 J sec-1 = 1 W).&lt;/p&gt;&#xA;&lt;p&gt;W m-2 = (m sec-1 (ΔJ m-3)) / 4&lt;/p&gt;&#xA;&lt;p&gt;One can see from the immediately-above equation that the Stefan-Boltzmann equation is all about subtracting the radiation energy density of the cooler object from the radiation energy density of the warmer object.&lt;/p&gt;&#xA;&lt;p&gt;∴ q = σ / a * Δe&lt;/p&gt;&#xA;&lt;p&gt;Canceling units, we get W m-2.&lt;/p&gt;&#xA;&lt;p&gt;W m-2 = (W m-2 K-4 / J m-3 K-4) * ΔJ m-3&lt;/p&gt;&#xA;&lt;p&gt;For graybody objects, it is the radiation energy density differential between warmer object and cooler object which determines warmer object radiant exitance.&lt;/p&gt;&#xA;&lt;p&gt;Remember that a warmer object will have higher energy density at all wavelengths than a cooler object:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qPJ94.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://i.stack.imgur.com/qPJ94.png&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This is why 2LoT in the Clausius Statement sense implies that system energy cannot ascend an energy density gradient,&amp;quot;without some other change, connected therewith, occurring at the same time&amp;quot;... that &amp;quot;some other change&amp;quot; typically being external energy pumping that system energy up the energy density gradient. That's what happens in, for instance, AC units and refrigerators.&lt;/p&gt;&#xA;&lt;p&gt;Most people cannot think in terms of energy, energy density and energy density gradient. We need to analogize to something they’re familiar with. Thus, just as, for instance, water only spontaneously flows down a pressure gradient, energy only spontaneously flows down an energy density gradient. That’s 2LoT in the Clausius Statement sense, in a nutshell. So one tack to take is to ask people if water can ever spontaneously flow uphill. Of course they’ll say, “No, water cannot flow uphill on its own.” Then show them dimensional analysis.&lt;/p&gt;&#xA;&lt;p&gt;mass (M), length (L), time (T), absolute temperature (K), amount of substance (N), electric charge (Q), luminous intensity (C)&lt;/p&gt;&#xA;&lt;p&gt;We denote the dimensions like this: [Mx, Lx, Tx, Kx, Nx, Qx, Cx] where x = the number of that dimension. We typically remove dimensions that are not used.&lt;/p&gt;&#xA;&lt;p&gt;Force:                      [M1 L1 T-2]     /&lt;/p&gt;&#xA;&lt;p&gt;Area:                       [M0 L2 T0]      =&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Pressure:                 [M1 L-1 T-2]&lt;/strong&gt;  /&lt;/p&gt;&#xA;&lt;p&gt;Length:                     [M0 L1 T0]      =&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Pressure Gradient:            [M1 L-2 T-2]&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Explain to them that Pressure is Force / Area, and that Pressure Gradient is Pressure / Length. Remind them that water only spontaneously flows down a pressure gradient (ie: downhill). Then introduce energy. Tell them that energy is much like water. It requires an impetus to flow, just as water requires an impetus (pressure gradient) to flow. In the case of radiative energy, that impetus is a radiation energy density gradient, which is analogous to (and in fact, literally is) a radiation pressure gradient.&lt;/p&gt;&#xA;&lt;p&gt;Energy:                     [M1 L2 T−2] /&lt;/p&gt;&#xA;&lt;p&gt;Volume:                     [M0 L3 T0]      =&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Energy Density:               [M1 L-1 T-2]&lt;/strong&gt;  /&lt;/p&gt;&#xA;&lt;p&gt;Length:                     [M0 L1 T0]      =&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Energy Density Gradient:  [M1 L-2 T-2]&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;p&gt;Explain to them that Energy Density is Energy / Volume, and Energy Density Gradient is Energy Density / Length. Highlight the fact that Pressure and Energy Density have the same units (&lt;strong&gt;bolded above&lt;/strong&gt;). Also highlight the fact that Pressure Gradient and Energy Density Gradient have the same units (&lt;strong&gt;bolded above&lt;/strong&gt;).&lt;/p&gt;&#xA;&lt;p&gt;So we’re talking about the same concept as water only spontaneously flowing down a pressure gradient (ie: downhill) when we talk of energy (of any form) only spontaneously flowing down an energy density gradient. Energy density &lt;strong&gt;is&lt;/strong&gt; pressure, an energy density gradient &lt;strong&gt;is&lt;/strong&gt; a pressure gradient… for energy.&lt;/p&gt;&#xA;&lt;p&gt;It’s a bit more complicated for gases because they can convert that energy density to a change in volume (1 J m-3 = 1 Pa), for constant-pressure processes, which means the unconstrained volume of a gas will change such that its energy density (in J m-3) will tend toward being equal to pressure (in Pa). This is the underlying mechanism for convection.&lt;/p&gt;&#xA;" OwnerUserId="30455" LastEditorUserId="30455" LastEditDate="2024-02-07T10:17:09.757" LastActivityDate="2024-02-07T10:17:09.757" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25956" PostTypeId="2" ParentId="10128" CreationDate="2024-02-07T10:30:17.817" Score="0" Body="&lt;p&gt;Backradek wrote:&#xA;&amp;quot;No, this is not the case. The atmosphere is almost black and opaque at certain wavelengths such as 15um (CO2). Then only the external layers radiate, mostly.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;Absolutely correct.&lt;/p&gt;&#xA;&lt;p&gt;Also remember that there exists a mean free path length / altitude / air density relation. Mean free path length increases exponentially with an increase in altitude.&lt;/p&gt;&#xA;&lt;p&gt;Thus the net mean free path length for upwelling radiation is longer than for downwelling radiation, and given the potentially millions upon millions of times re-emitted radiation could be re-absorbed / re-emitted in random directions, this means that a very great majority of downwelling radiation is redirected to upwelling... especially so with the ~10.4 m surface-level extinction depth at 14.98352 µm wavelength.&lt;/p&gt;&#xA;&lt;p&gt;Given that ~10.4 m extinction depth and the nature of absorption (50% being absorbed within the first 10% of that depth,50% of the remainder being absorbed in the next 10% of that depth, 50% of the remainder being absorbed in the next 10% of that depth, etc., etc., etc.) that would mean that fully 50% of the so-called 'backradiation' from CO2 would have to come from within ~1.04 m of the surface... where there would be practically no energy density gradient between surface and atmosphere.&lt;/p&gt;&#xA;" OwnerUserId="30455" LastActivityDate="2024-02-07T10:30:17.817" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25957" PostTypeId="1" CreationDate="2024-02-08T16:50:11.623" Score="0" ViewCount="87" Body="&lt;p&gt;Since climate change is such a big topic and the world is investing billions of dollars each year.&#xA;Are there any controlled studies of CO2 as a greenhouse gas?&lt;/p&gt;&#xA;&lt;p&gt;It's quite simple:&#xA;build two 3mx3mx3m transparent cubes beside each other, one with CO2 at 350ppm, the other with CO2 at 700 ppm, record all the temperatures every hour, and compare them.&#xA;It would be amazing to put those in Science Centers around the world. So the public can have a clear ideas on how CO2 induced climate change works.&lt;/p&gt;&#xA;" OwnerUserId="30459" LastEditorUserId="30459" LastEditDate="2024-02-08T16:50:36.977" LastActivityDate="2024-02-11T00:55:04.003" Title="Controlled studies of CO2 as a greenhouse gas" Tags="|climate-change|climate|co2|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25958" PostTypeId="1" CreationDate="2024-02-09T10:59:38.420" Score="3" ViewCount="88" Body="&lt;p&gt;I am currently looking for a good illustration of the currents in the N atlantic. They should not be extremely complex, but they should be realistic. I have now found a figure that I am very happy with, but I am wondering where the AMOC is located in the figure, because the AMOC is NOT the Gulf Stream. Do you have better illustrations or do you know where the AMOC is located or why it is not specifically shown?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LgNQJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LgNQJ.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://courses.seas.harvard.edu/climate/eli/Courses/misc/201209-Mallorca/Sources/2-THC/from-EPS131/2-RAPID/gulf_stream.php.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-02-21T09:25:13.580" LastActivityDate="2024-02-21T09:25:13.580" Title="Where is the AMOC located in this Fig?" Tags="|ocean-currents|atlantic|amoc|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="25960" PostTypeId="1" CreationDate="2024-02-09T21:14:58.793" Score="3" ViewCount="35" Body="&lt;p&gt;Thinking about arc volcanism in a region, and there are two neighboring composite volcanoes 50 km apart from each other.&lt;/p&gt;&#xA;&lt;p&gt;Do you expect any differences about their products (lavas, pyroclastic deposits)?&#xA;Does each volcano have a fingerprint property?&lt;/p&gt;&#xA;&lt;p&gt;Possibly a geochemical difference...&lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="2470" LastEditDate="2024-02-10T05:35:25.427" LastActivityDate="2024-02-10T05:35:25.427" Title="Does each volcano have a fingerprint?" Tags="|geochemistry|volcanology|magmatism|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25961" PostTypeId="2" ParentId="25957" CreationDate="2024-02-10T04:42:51.753" Score="2" Body="&lt;p&gt;It may be possible to have a demonstration experiment that shows the absorptive properties of CO2 but not as described. Nothing so simple -&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/LaozO.gif&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/LaozO.gif&quot; alt=&quot;greenhouse effect diagram&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;It is important to consider that the greenhouse effect works within a depth of atmosphere from sea level to low to mid stratosphere, ie much greater distance than 3m (up to 20,000m)- albeit with declining density and effect as the altitude rises. The rate of current warming &lt;em&gt;averages&lt;/em&gt; around 0.2 C per decade, with periods of 3 decades preferred to avoid misconstruing natural climate variability for a trend. That is not conducive to hour to hour or day to day or even year to year measurement; averaging of highly varying temperatures over a sufficient time that a longer term trend can be determined is required.&lt;/p&gt;&#xA;&lt;p&gt;I think John Tyndall's equipment for testing the radiant heat absorption of gases including CO2 - that, as a consequence of explaining how Earth's average temperature could be what it was, laid the groundwork for understanding that human activities, especially fossil fuel burning could change it - does look the part -&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/qILPm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/qILPm.png&quot; alt=&quot;Tyndall&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="18145" LastEditorUserId="18145" LastEditDate="2024-02-11T00:55:04.003" LastActivityDate="2024-02-11T00:55:04.003" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25963" PostTypeId="1" CreationDate="2024-02-10T20:59:50.613" Score="2" ViewCount="34" Body="&lt;p&gt;Do Pumice and obsidian pyroclasts from a single explosion have the same chemical composition?&lt;/p&gt;&#xA;&lt;p&gt;For same vent, same eruption.&#xA;Obsidian is a glass and pumice is a glass too.&#xA;They must have the same chemical composition. Have they?&lt;/p&gt;&#xA;" OwnerUserId="15195" LastActivityDate="2024-02-10T20:59:50.613" Title="Do Pumice and obsidian pyroclasts from a single explosion have the same chemical composition?" Tags="|volcanology|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25966" PostTypeId="2" ParentId="10396" CreationDate="2024-02-11T12:19:26.840" Score="0" Body="&lt;p&gt;Not only have we mined mountains out of existence (and are still doing so), we have also done the same with at least one mineral. &lt;a href=&quot;https://en.wikipedia.org/wiki/Cryolite&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cryolite&lt;/a&gt; was once present as a large deposit in Greenland, where it was mined as an aluminum ore and later for a flux in the electrowinning of aluminum from refined oxide ores. In 1987 this source became too depleted for commercial mining to continue, and while the mineral still technically exists in Greenland and elsewhere it is now considered rare and not commercially mineable. As if in a real-life version of the 2012 sequel of &lt;em&gt;The Lorax&lt;/em&gt;, cryolite used today is now made artificially using fluorite as the fluoride sourflce.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastActivityDate="2024-02-11T12:19:26.840" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25967" PostTypeId="1" CreationDate="2024-02-11T14:35:31.910" Score="4" ViewCount="219" Body="&lt;p&gt;This question is related to this &lt;a href=&quot;https://earthscience.stackexchange.com/questions/25958/where-is-the-amoc-located-in-this-fig&quot;&gt;question&lt;/a&gt;. I am currently trying to understand which currents in the North Atlantic are counted as part of the AMOC:&lt;/p&gt;&#xA;&lt;p&gt;I am sure about the currents:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;N. Atlantic current&lt;/li&gt;&#xA;&lt;li&gt;Norwegian Current&lt;/li&gt;&#xA;&lt;li&gt;Gulf Stream&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;For the currents:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Norwegan Current&lt;/li&gt;&#xA;&lt;li&gt;Baffin Bay&lt;/li&gt;&#xA;&lt;li&gt;Canarias current&lt;/li&gt;&#xA;&lt;li&gt;North Atlantic Deep Water Current&lt;/li&gt;&#xA;&lt;li&gt;Irminger Current&lt;/li&gt;&#xA;&lt;li&gt;West Greenland Current&lt;/li&gt;&#xA;&lt;li&gt;E Greenland Current&lt;/li&gt;&#xA;&lt;li&gt;Irminger Current&lt;/li&gt;&#xA;&lt;li&gt;North Iceland Irminger Current&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;I´m not so sure. I find some contradictory &lt;a href=&quot;https://en.wikipedia.org/wiki/North_Atlantic_Current&quot; rel=&quot;nofollow noreferrer&quot;&gt;literature&lt;/a&gt; (I do know Wiki isn´t the best source but nice to get an overview) on these currents. Whilst some mention these currents, they are hardly mentioned in other &lt;a href=&quot;https://www.whoi.edu/know-your-ocean/ocean-topics/how-the-ocean-works/ocean-circulation/the-ocean-conveyor/&quot; rel=&quot;nofollow noreferrer&quot;&gt;literature&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Even this figure didn´t make it clear which currents are related towards the AMOC&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ACzh8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ACzh8.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Do you have a good list of which currents are included?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-03-12T10:26:27.333" LastActivityDate="2024-03-12T10:26:27.333" Title="Which currents are counted as AMOC in the North Atlantic and which are not?" Tags="|oceanography|ocean-currents|ocean-models|amoc|northatlantic|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25968" PostTypeId="1" CreationDate="2024-02-12T21:00:45.063" Score="2" ViewCount="22" Body="&lt;p&gt;I'm an engineer doing some R&amp;amp;D designing a new product to measure some interesting soil parameters, and integrating a multi-pronged sensor probe to take the measurements. I'm considering making this product just because it's possible to do it. The probe claims to be able to provide measurements for:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Conductivity [mS/cm in the range of 0 to 10000 with resolution of 10]&lt;/li&gt;&#xA;&lt;li&gt;pH [in the range of 3 to 9 with resolution of 0.01pH and accuracy of +/-0.3pH]&lt;/li&gt;&#xA;&lt;li&gt;Nitrogen, Phosphorus, and Potassium content [mg/kg in the range of 0 to 2000 with accuracy of +/-40 (2% of full scale)]&lt;/li&gt;&#xA;&lt;li&gt;Temperature and Humidity&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I had an old pot with some (very dry / loose) dirt that I grabbed from the garage because I wanted to see what the probe measured, and it consistently gave me a reading of 7pH and zeros for everything else. Not very scientific.&lt;/p&gt;&#xA;&lt;p&gt;How do I create repeatable test soil samples that I can stick the probe into that gives me non-zero / known values for these parameters (besides temperature, which seems reasonable) so I can tell if this probe provides anything resembling useful information?&lt;/p&gt;&#xA;" OwnerUserId="30480" LastActivityDate="2024-02-12T21:00:45.063" Title="Meaningful Tests to challenge a Soil Probe" Tags="|soil|soil-science|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25969" PostTypeId="1" CreationDate="2024-02-13T17:03:10.863" Score="1" ViewCount="15" Body="&lt;p&gt;Is there any scientific guess/measurement of the average strain rate as a function of depth in the Earth's mantle?&#xA;Thinking about mantle convection, I'm curious if there was ever an estimation about the average strain rates that are happening across the mantle. I couldn't find any references for olivine, but maybe someone knows better.&lt;/p&gt;&#xA;" OwnerUserId="8049" LastActivityDate="2024-02-13T17:03:10.863" Title="Strain rates of olivine in the upper mantle?" Tags="|mantle|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25971" PostTypeId="1" CreationDate="2024-02-13T20:03:09.527" Score="0" ViewCount="35" Body="&lt;p&gt;From &lt;a href=&quot;https://www.youtube.com/watch?v=ouTJkNLepF0&quot; rel=&quot;nofollow noreferrer&quot;&gt;Crash Course Engineering&lt;/a&gt;, understanding the movement of fluids requires knowing:&lt;/p&gt;&#xA;&lt;ol&gt;&#xA;&lt;li&gt;Shear Stress&lt;/li&gt;&#xA;&lt;li&gt;Shear Strain&lt;/li&gt;&#xA;&lt;li&gt;Viscosity&lt;/li&gt;&#xA;&lt;/ol&gt;&#xA;&lt;p&gt;Now, I understand that &lt;em&gt;Shear Stress&lt;/em&gt; causes &lt;em&gt;Shear Strain&lt;/em&gt;, and depending on the &lt;em&gt;Viscosity&lt;/em&gt; of the fluid, this makes the fluid move in some way. However, in my Sedimentology class, they never talk about shear strain, and only about shear stress. The example they use is from Boggs:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/dlH1L.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dlH1L.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This makes no sense whatsoever, as it is treating shear strain like shear stress, and yet they are completely different concepts. It gets more confusing, as the equations they are using are for shear strain, and not shear stress. Furthermore, every single diagram for shear &amp;quot;stress&amp;quot; in a liquid involves the one above, but what is even happening here? If I take a block of wood, place it on a tub of water, and push it across the water, I do not see how the motion depicted above is even possible. This also contradicts the example my professor shown in class:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/BixuH.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BixuH.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Why is the velocity gradient larger for the molasses? Since it is more viscous, should not the gradient be extremely small?&lt;/p&gt;&#xA;&lt;p&gt;I am a visual learner, and not only are they using &amp;quot;shear stress&amp;quot; wrong to my knowledge, but the visual makes no practical sense; I can not find any demonstration online either. Can anyone better explain how &amp;quot;shear stress&amp;quot; and viscosity work? Why is &amp;quot;shear stress&amp;quot; used incorrectly, and why is a visual of shear strain used for the visual of &amp;quot;shear stress&amp;quot;?&lt;/p&gt;&#xA;" OwnerUserId="29777" LastEditorUserId="29777" LastEditDate="2024-02-13T20:26:41.833" LastActivityDate="2024-02-13T20:26:41.833" Title="How exactly does &quot;shear stress&quot; and &quot;viscosity&quot; work when it comes to a fluid?" Tags="|hydrology|sedimentology|visualization|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25973" PostTypeId="1" CreationDate="2024-02-13T21:08:09.307" Score="2" ViewCount="69" Body="&lt;p&gt;When surveying penguin colonies on subantarctic Antipodes Island, we found a cave that features a strange rock formation:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/VBMZO.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/VBMZO.jpg&quot; alt=&quot;Rock cairn or natural formation?&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The formation does not appear to be particularly exposed to the elements so that abrasive forces may not be at work here. The cave is located in a large bay in the northwest of the island that is only accessible from the sea. Today the bay hosts a large colony of fur seals that were nearly hunted to extinction by sealers in the early 1800s. The cave would be a perfect spot for the sealers to camp out and stash the skins, so it is plausible that it served as a base for sealing operations. Hence, the possibility that the formation is indeed man made.&lt;/p&gt;&#xA;&lt;p&gt;However, the rocks it consists of look rather large and potentially heavy which would speak for a natural rock formation.&lt;/p&gt;&#xA;&lt;p&gt;Probably relevant to mention that Antipodes Island is of volcanic origin.&lt;/p&gt;&#xA;&lt;p&gt;Any opinions of folks with knowledge in Geology would be greatly appreciated!&lt;/p&gt;&#xA;&lt;p&gt;Here is a 4K video of the &amp;quot;cairn&amp;quot; filmed with a drone: &lt;a href=&quot;https://www.youtube.com/watch?v=j9imJUytp6Y&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.youtube.com/watch?v=j9imJUytp6Y&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="30487" LastActivityDate="2024-03-15T02:05:00.553" Title="Subantarctic islands: man-made rock cairn or natural formation?" Tags="|rocks|geomorphology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25975" PostTypeId="2" ParentId="25973" CreationDate="2024-02-14T01:54:02.320" Score="-1" Body="&lt;p&gt;The fur collection on Antipodes Island lasted for about seven years or so, from 1800 to 1807. This is an extremely isolated island that lies at the boundary between the roaring forties and furious fifties.&lt;/p&gt;&#xA;&lt;p&gt;How could a small, ragtag group of sailors have brought the heavy machinery to that extremely remote island needed to carve that cave in a mere seven years? OTOH, the island is volcanic, is chock full of caves, and is subject to some of the most severe storms on the planet. It's almost certainly a natural formation.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2024-02-14T01:54:02.320" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25976" PostTypeId="1" AcceptedAnswerId="26000" CreationDate="2024-02-14T05:19:11.383" Score="2" ViewCount="83" Body="&lt;p&gt;I'm a meteorology student, and this sentence in my lab book confused me: &amp;quot;Both sensible and latent heat are transferred by winds.&amp;quot;&lt;/p&gt;&#xA;&lt;p&gt;I understand how sensible heat could be transported by wind—it literally blows air which has a higher temperature to a different place. I understand what latent heat is (energy which goes into evaporation rather than actually changing the air temperature), but I don't understand how this could be transported the same way by winds.&lt;/p&gt;&#xA;&lt;p&gt;Is this just moisture advection? Would it be correct to say that it is the transport of air with moisture that has more energy (closer to phase change), but no more temperature?&lt;/p&gt;&#xA;&lt;p&gt;Thanks in advance!&lt;/p&gt;&#xA;" OwnerUserId="30490" LastActivityDate="2024-02-23T20:51:32.030" Title="How does the wind transport latent heat?" Tags="|meteorology|" AnswerCount="2" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25977" PostTypeId="1" CreationDate="2024-02-14T10:41:25.887" Score="1" ViewCount="39" Body="&lt;p&gt;I would like to know if there is a link between WHC and humidity. I have a compost with a maximum retention capacity of 500 mL/L and a moisture content of 77%. I have about 290g of compost in each container and this compost has a density of 588g/L. Is there any way of knowing from this data what percentage of WHC I have? For example 80% WHC, 20% ... ?&lt;/p&gt;&#xA;&lt;p&gt;Thank you in advance for your help.&lt;/p&gt;&#xA;" OwnerUserId="30493" LastActivityDate="2024-02-14T10:41:25.887" Title="Relation between water holding capacity and moisture content" Tags="|soil|soil-science|soil-moisture|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="25978" PostTypeId="1" AcceptedAnswerId="25987" CreationDate="2024-02-16T09:09:47.737" Score="4" ViewCount="44" Body="&lt;p&gt;In metamorphic petrogenesis; you can infer the occurrence pressure and temperature of the rock from the minerals and other features inside, with various instrumental techniques.&lt;/p&gt;&#xA;&lt;p&gt;Is there any scientific method (possible a forensic method) which gives the temperature of the burning?&lt;/p&gt;&#xA;&lt;p&gt;A wood specimen is found in the field and it is known that it was heated before, in some degree, in a volcanic environment and one wants to investigate the heating temperature that the wood had encountered.&lt;/p&gt;&#xA;" OwnerUserId="15195" LastEditorUserId="15195" LastEditDate="2024-02-18T08:29:04.180" LastActivityDate="2024-02-20T16:56:50.750" Title="How can you infer the burning degree (Celcius etc) of a wood from a heat effected specimen?" Tags="|volcanology|volcanic-hazard|metamorphism|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25979" PostTypeId="1" AcceptedAnswerId="25980" CreationDate="2024-02-16T14:37:54.510" Score="0" ViewCount="38" Body="&lt;p&gt;I would like to convert &lt;code&gt;μmol C/m2&lt;/code&gt; to &lt;code&gt;kg C/ ha&lt;/code&gt;. Does anybody have any suggestions on how to do it? Based on ChatGPT It can be converted as follows:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rF7cd.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rF7cd.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;But I am not sure if this is correct. Thank you in advance&lt;/p&gt;&#xA;" OwnerUserId="30501" LastActivityDate="2024-02-16T17:54:34.360" Title="Coversion of μmol/m2 to kg/ m2" Tags="|carbon|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25980" PostTypeId="2" ParentId="25979" CreationDate="2024-02-16T17:54:34.360" Score="2" Body="&lt;p&gt;Yes, that's just unit conversion, so convert umol to mol (&lt;span class=&quot;math-container&quot;&gt;$10^{-6}$&lt;/span&gt;), multiply by the molar mass (~44 g/mol), and convert g to kg (&lt;span class=&quot;math-container&quot;&gt;$10^{-3}$&lt;/span&gt;) and &lt;span class=&quot;math-container&quot;&gt;$m^{-2}$&lt;/span&gt; to &lt;span class=&quot;math-container&quot;&gt;$ha^{-1}$&lt;/span&gt; (&lt;span class=&quot;math-container&quot;&gt;$10^4$&lt;/span&gt;).  The final conversion factor should be:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$$ 4.4\times10^1\times10^{-6}\times10^{-3}\times10^4 = 4.4\times10^{-4} \frac{kg/ha}{\mu mol/m^2} $$&lt;/span&gt;&lt;/p&gt;&#xA;" OwnerUserId="26713" LastActivityDate="2024-02-16T17:54:34.360" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25981" PostTypeId="1" CreationDate="2024-02-17T21:24:11.540" Score="3" ViewCount="96" Body="&lt;p&gt;In this image from the 2023 earthquake in Turkey (and many others online), the railway is badly deformed, but structures around it (e.g., the concrete wall to the right and berm to the left) seem unaffected.  What's the mechanism that causes this kind of seemingly-isolated damage to railroads in a earthquake?&lt;/p&gt;&#xA;&lt;p&gt;&lt;img src=&quot;https://media.zenfs.com/en/gizmodo_news_915/00a5bd213cc664babaaadcf7bc03fe7c&quot; alt=&quot;&quot; /&gt;&lt;/p&gt;&#xA;" OwnerUserId="30504" LastActivityDate="2024-02-20T23:17:51.427" Title="How does an earthquake bend rail road rails, but not damage the surrounding structures?" Tags="|earthquakes|" AnswerCount="1" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="25982" PostTypeId="2" ParentId="25976" CreationDate="2024-02-18T00:02:49.110" Score="1" Body="&lt;p&gt;In a fundamental sense, it is advection. The difference between advection and turbulent transport is a question of averages.&lt;/p&gt;&#xA;&lt;p&gt;What I think this is referring to is known as the drag law. Consider the turbulent flux (or covariance) of moisture (&lt;span class=&quot;math-container&quot;&gt;$\overline{w'q'}$&lt;/span&gt;): &lt;span class=&quot;math-container&quot;&gt;$$\overline{w'q'}=C_qU\Delta q$$&lt;/span&gt; where &lt;span class=&quot;math-container&quot;&gt;$C_q$&lt;/span&gt; is the transfer (or drag) coefficient, &lt;span class=&quot;math-container&quot;&gt;$U$&lt;/span&gt; is the wind speed, and &lt;span class=&quot;math-container&quot;&gt;$\Delta q$&lt;/span&gt; is the difference in moisture between the surface and the air. There is a similar relationship between sensible heat flux- simply replace &lt;span class=&quot;math-container&quot;&gt;$C_q$&lt;/span&gt; with &lt;span class=&quot;math-container&quot;&gt;$C_h$&lt;/span&gt; and &lt;span class=&quot;math-container&quot;&gt;$\Delta q$&lt;/span&gt; with &lt;span class=&quot;math-container&quot;&gt;$\Delta T$&lt;/span&gt;. You can think of this as a fan blowing heat and sweat off of a professional athlete. All of this should boil into &lt;a href=&quot;https://geo.libretexts.org/Bookshelves/Meteorology_and_Climate_Science/Practical_Meteorology_(Stull)/18%3A_Atmospheric_Boundary_Layer/18.04%3A_Section_5-&quot; rel=&quot;nofollow noreferrer&quot;&gt;K-theory&lt;/a&gt; and the log-wind profile.&lt;/p&gt;&#xA;&lt;p&gt;There is a second way that I interpret this statement. When water is condensed, the water itself can be transported. So really latent heat is just your latent heat of vaporization (or deposition) multiplied against the air density and mixing ratio. Since the wind can blow microphyics, it inherently blows latent heat. But since sensible heat is mentioned, I am inclined more towards the first explanation.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2024-02-18T00:02:49.110" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25983" PostTypeId="1" CreationDate="2024-02-18T13:02:39.600" Score="1" ViewCount="44" Body="&lt;p&gt;Devitrification is the crystallization of volcanic glass to crystals. Obsidian groundmass -black in color- turns to white with devitrification.&lt;/p&gt;&#xA;&lt;p&gt;I want to learn why devitrification takes place.&lt;/p&gt;&#xA;&lt;p&gt;Attached photo, exhibits an example of devitrification, which i had taken in the field. &lt;a href=&quot;https://i.stack.imgur.com/1s6P6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1s6P6.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="15195" LastActivityDate="2024-02-18T13:02:39.600" Title="In which conditions ignimbrites devitrifies?" Tags="|volcanology|volcanic-eruption|pyroclastic-flows|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="25984" PostTypeId="1" AcceptedAnswerId="25986" CreationDate="2024-02-19T09:58:07.287" Score="4" ViewCount="87" Body="&lt;p&gt;I recently stumbled on the images of the &lt;a href=&quot;https://en.wikipedia.org/wiki/Cosquer_Cave&quot; rel=&quot;nofollow noreferrer&quot;&gt;Cosquer cave&lt;/a&gt;, located in France, famous for being a comparatively recently discovered as a Paleolithic decorated cave.&lt;/p&gt;&#xA;&lt;p&gt;The entrance to cave now is more than 30m below waterline, and, according to Wikipedia, has presumably been underwater since Holocene.&lt;/p&gt;&#xA;&lt;p&gt;In the photo attached, we can see the diver breathing the cave air.&lt;/p&gt;&#xA;&lt;p&gt;I started to wonder, what would the initial air composition be, when the cave was entered by humans, if we assume the cave was in rocky strata, and the only source of gas for a long period of time was the seawater column.&lt;/p&gt;&#xA;&lt;p&gt;Would it be correct to say that the air composition should be similar to what it was when cave started being underwater, or are there processes which would ensure the air in it would be similar to the one in the outside atmosphere nearby?&lt;/p&gt;&#xA;&lt;p&gt;I understand there can be several ways in which gas exchange could happen&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5CVQa.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5CVQa.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="11756" LastActivityDate="2024-02-19T19:39:24.040" Title="Likely air composition in cave only accessible from underwater?" Tags="|geology|geochemistry|hydrology|atmospheric-chemistry|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25985" PostTypeId="2" ParentId="25890" CreationDate="2024-02-19T19:30:05.643" Score="3" Body="&lt;p&gt;The atmospheric height is a difficult concept to explain to someone new. I've learned that the best way to talk about it is to specify it parenthetically. In other words, it is the geopotential height (of the 500 hPa isobaric surface).&lt;/p&gt;&#xA;&lt;p&gt;The 5.5 km estimate is just that- an estimate or rule of thumb. It goes down in areas of low pressure (and when the average column of air is cool) and goes up in areas of high pressure (and when the average column of air is warm). So while those who may be very particular with their numbers may object, it is &lt;em&gt;roughly&lt;/em&gt; about 50% of the pressure and 50% of the mass. So you are roughly correct. If you go up halfway through the atmosphere, you still have half of the atmosphere weighing down on you. I'd give that a correct on an exam.&lt;/p&gt;&#xA;&lt;p&gt;Generally, as you go up into the atmosphere, you have less atmosphere weighing down on you. That's why people need oxygen masks on Mt. Everest and some higher altitude flights are pressurized.&lt;/p&gt;&#xA;&lt;p&gt;Now my experience is that students struggle more with the spatiotemporal variations (as I stated in the beginning). But really it is the pressure varying in time and space, and plots of the geopotential heights of isobaric surfaces showing how far up until you reach that pressure. And the key to this is the &lt;a href=&quot;https://en.wikipedia.org/wiki/Barometric_formula#Derivation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Barometric formula&lt;/a&gt;, used interchangeably with the &lt;a href=&quot;https://en.wikipedia.org/wiki/Hypsometric_equation#Derivation&quot; rel=&quot;nofollow noreferrer&quot;&gt;Hypsometric equation&lt;/a&gt; and hydrostatic equation. Synoptic scale variations in the geopotential height of isobaric surfaces are often attributable to the &lt;a href=&quot;https://en.wikipedia.org/wiki/Scale_height&quot; rel=&quot;nofollow noreferrer&quot;&gt;scale height&lt;/a&gt;.&lt;/p&gt;&#xA;" OwnerUserId="704" LastActivityDate="2024-02-19T19:30:05.643" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25986" PostTypeId="2" ParentId="25984" CreationDate="2024-02-19T19:39:24.040" Score="4" Body="&lt;p&gt;Considering the presence of speleothems, indicating the infiltration of water along fractures (i.e. fracture permeability), and the range of daily tides in the vicinity (noted as presently about 0.8 ft, or 0.24 m), one would suspect that there is at present an exchange of air with the exterior atmosphere.  Air would be gently pulled into the cave along permeable fractures during the transition to low tide, and be similarly exhausted during the transition to high tide.  Consequently, the composition of the air in the cave would be similar to, or exactly the same as, the exterior air outside of the cave.&lt;/p&gt;&#xA;" OwnerUserId="30512" LastActivityDate="2024-02-19T19:39:24.040" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25987" PostTypeId="2" ParentId="25978" CreationDate="2024-02-20T16:56:50.750" Score="2" Body="&lt;p&gt;There has been a recent study about this: &lt;a href=&quot;https://doi.org/10.1038/s41598-023-32623-3&quot; rel=&quot;nofollow noreferrer&quot;&gt;Pensa et al. (2023)&lt;/a&gt; used charcoal samples found in the deposits of the 79 CE eruption of Mount Vesuvius to infer the temperature of its pyroclastic density currents. They used reflectance analysis of the charcoal samples, with the maximum reflectance values being associated with the &lt;em&gt;minimum temperature of the peak thermal conditions&lt;/em&gt;. You can read the &amp;quot;Charcoal reflectance analysis&amp;quot; section and references therein for more details about this method.&lt;/p&gt;&#xA;&lt;p&gt;However, bear in mind that you need several charcoal pieces sampled across various sites of your volcanic environment to have a better idea of the heat distribution it experienced while being emplaced. This study found quite a wide range of temperatures depending on the unit considered and/or the location sampled within the same unit. With one wood sample, you'd only have an idea of the temperature this exact location experienced, which is still valuable but cannot be extrapolated to the whole unit.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2024-02-20T16:56:50.750" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25988" PostTypeId="1" CreationDate="2024-02-20T21:51:40.183" Score="1" ViewCount="22" Body="&lt;p&gt;I read that the deepest part of the Grand Canyon that we can see are the Vishnu Basement Rocks, deposited 2 billion years ago (according to the Grand Canyon Wikipedia page). But what kind of rock lies beneath the Vishnu rock layer? The Grand Canyon is a mile deep, but continental crust is tens of miles thick. What makes up the remainder?&lt;/p&gt;&#xA;" OwnerUserId="30520" LastActivityDate="2024-02-20T21:51:40.183" Title="What rock layer is beneath the Vishnu Basement Rock in the Grand Canyon?" Tags="|geology|regional-geology|bedrock|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25989" PostTypeId="2" ParentId="25981" CreationDate="2024-02-20T23:10:35.357" Score="1" Body="&lt;p&gt;this is what liquefaction looks like, the ground acts like a liquid, this is not ground flow, this is the ground as a whole doing the chacha (s-wave) and the rail going along for the ride. but the rail is strong enough to hold the tailings in place as the ground returns to normal but the rail remains bent. you are basically looking at a freeze frame if what the ground was doing at time time but the rails kind of lock it in place. you are just looking at where the rails bent but did not return.&lt;/p&gt;&#xA;&lt;p&gt;also remember a rail like this is essentially one continuous piece of steel for miles, there could be a lot of stress being transferred from other areas.&lt;/p&gt;&#xA;&lt;p&gt;This is what happens when the rails are not as well anchored. and pull themselves away from the soil as the ground returns to normal.  &lt;a href=&quot;https://i.stack.imgur.com/0XhEW.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/0XhEW.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/B9780857092687500050&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/abs/pii/B9780857092687500050&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="7080" LastEditorUserId="7080" LastEditDate="2024-02-20T23:17:51.427" LastActivityDate="2024-02-20T23:17:51.427" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25990" PostTypeId="1" CreationDate="2024-02-21T06:57:02.867" Score="3" ViewCount="32" Body="&lt;p&gt;The title pretty much says it all. I cannot find a satisfactory definition of &amp;quot;lattice bound&amp;quot;, just a number of examples of it being used in literature. For example, in &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0892687518302553&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; paper about removing lattice bound trace elements from quartz, I understand how germanium or titanium is quite literally a part of the lattice and not interstitial and the charge compensators are not, but quartz has a very simple unit cell.&lt;/p&gt;&#xA;&lt;p&gt;In illite or, more importantly for me, in glauconite is iron bound in the octahedral sites considered &amp;quot;lattice bound&amp;quot; and why? Is this an octahedral void they are occupying or not?&#xA;As a bonus I would love to know how both oxidation states of iron (2+ and 3+) can be bound in glauconite simultaneously. Are they both occupying octahedral sites or are they bound in different structural sites depending on oxidation number?&lt;/p&gt;&#xA;" OwnerUserId="29921" LastActivityDate="2024-02-27T00:40:20.117" Title="What is a good definition for &quot;lattice bound&quot; and is iron within octahedral sites of illite considered lattice bound or interstitial?" Tags="|geochemistry|mineralogy|sedimentology|crystallography|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25991" PostTypeId="2" ParentId="228" CreationDate="2024-02-22T03:03:02.817" Score="1" Body="&lt;p&gt;The Calcite Compensation Depth (CCD) is the depth at which the dissolution of calcite outpaces the accumulation of calcitic sediments. This is distinct from the Aragonite Compensation Depth (ACD), which is similar to the CCD in that it is the depth at which aragonite sediments dissolve faster than they can accumulate. The ACD is generally shallower than the CCD.&lt;/p&gt;&#xA;&lt;p&gt;Further below the CCD, where the dissolution of opal outpaces the accumulation rate of opaline sediments we have the, you guessed it, Opal Compensation Depth (OPC). These depth boundaries are all a function of pressure and temperature; carbonaceous materials being more soluble at low temperatures and high pressures. Thus, deep cold seawater can hold more calcite and aragonite and will dissolve it faster than those sediments are able to accumulate. There is no net accumulation of these sediments below their relevant compensation depth.&lt;/p&gt;&#xA;&lt;p&gt;The sediments we are referring to are biogenic carbonate (and silica/opal, I'll go over  that in a second) tests, or skeletal and shell materials, made by planktonic, nektonic, and benthonic organisms floating around in the water column. These sorts of sediments generally only become important away from the continental edge, where they are no longer diluted by terrigenous sediments. I'll say that in a different way in case it isn't clear: there is a gradational pattern of sedimentation on the seafloor as you move away from continents, further out into ocean proper. When fine sands and silts are no longer being carried out and deposited onto the seafloor, then these biogenic sediments become relatively enriched because they are really the only thing accumulating (along with some red clays) and form carbonaceous and siliceous oozes (unconsolidated sediments that are &amp;gt;30% biogenic material). Above the ACD aragonitic, calcitic, and siliceous sediments dominate. Further out, and/or, deeper in the ocean, we hit the ACD and those aragonitic sediments are winnowed out. Now we only have calcitic and siliceous sediments so we're making carbonaceous oozes generally. Even further/deeper and we hit the CCD, the calcite seds are removed and now we're only accumulating siliceous sediments; we're making siliceous oozes. Again, we go deeper, and we hit the OCD. Now only red clays are accumulating. This is an idealized gradational scale, changes in topography can bring the seafloor back up above one of these boundaries, for example at a mid ocean ridge. Or maybe the continental shelf drops off too quickly and those terrigenous continent derived sediments are not winnowed out before we cross the CCD. In that case we would never form carbonaceous oozes.&lt;/p&gt;&#xA;&lt;p&gt;Because these depths are related to the solubility of the minerals, they can be raised or depressed by increasing the amount of that mineral we are pumping into the system. In other words, if you have a big boom in primary productivity somewhere over the pacific and plankton are growing like crazy, the CCD is &lt;em&gt;&lt;strong&gt;depressed&lt;/strong&gt;&lt;/em&gt;, often by as much as 500m. This is because all of that calcite floating down is saturating those cold bottom waters, so we have to move even deeper to reach a point where the water is able to hold more calcite and dissolution outpaces accumulation again.&lt;/p&gt;&#xA;&lt;p&gt;The depth of the CCD is also higher at the poles/rises towards northern (colder) latitudes and sinks towards the warmer equatorial waters.&lt;/p&gt;&#xA;&lt;p&gt;Hope that helps.&lt;/p&gt;&#xA;&lt;p&gt;here is a good resource if you'd like to learn more or rake in those details: &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/B9780444530004000044&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/science/article/pii/B9780444530004000044&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="29921" LastActivityDate="2024-02-22T03:03:02.817" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25992" PostTypeId="1" AcceptedAnswerId="26017" CreationDate="2024-02-22T13:01:01.757" Score="3" ViewCount="112" Body="&lt;p&gt;Hi If you look at the warm water currents in the N Atlantic, you can see how they have an overall eastward movement pattern:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/dTRBE.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/dTRBE.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.whoi.edu/know-your-ocean/ocean-topics/how-the-ocean-works/ocean-circulation/the-ocean-conveyor/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;If you compare this with the Coriolis forces, which also turn in an easterly direction in the N hemisphere, I wonder if there is a correlation? Or whether the current is only controlled by the continental masses?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/y0fEI.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/y0fEI.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://studyflix.de/ingenieurwissenschaften/corioliskraft-berechnen-1915&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-02-23T08:16:42.237" LastActivityDate="2024-02-27T09:53:32.967" Title="Are oceanic currents influenced by the Coriolis forces?" Tags="|oceanography|ocean-currents|atlantic|amoc|northatlantic|" AnswerCount="2" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25993" PostTypeId="5" CreationDate="2024-02-22T13:56:05.560" Score="0" Body="&lt;p&gt;Atlantic meridional overturning circulation&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-02-24T04:09:08.477" LastActivityDate="2024-02-24T04:09:08.477" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25994" PostTypeId="4" CreationDate="2024-02-22T13:56:05.560" Score="0" Body="Atlantic meridional overturning circulation" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-02-24T04:09:20.953" LastActivityDate="2024-02-24T04:09:20.953" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25995" PostTypeId="1" CreationDate="2024-02-22T20:31:56.017" Score="2" ViewCount="41" Body="&lt;p&gt;My guess as to the answer to my own question:&lt;/p&gt;&#xA;&lt;p&gt;Over a long period of time, no matter what the &lt;em&gt;original&lt;/em&gt; composition of the air pocket was, it will exchange gases with the seawater just below it, which will in turn mix with the effectively unlimited supply of seawater beyond. As a result, the proportional gas composition of the air pocket will eventually match that of the seawater, which tends to be lower in dissolved N2, and higher in O2 and CO2 than the regular atmosphere. As a result, it would not be breathable by people because of the excess of CO2.&lt;/p&gt;&#xA;&lt;p&gt;Is my reasoning sound, or have I missed something?&lt;/p&gt;&#xA;" OwnerUserId="30530" LastActivityDate="2024-02-22T20:31:56.017" Title="Assuming no nearby animal/plant life or other 'artifical' influences, would a trapped pocket of air under 50-60 meters of seawater be breathable?" Tags="|oceanography|water|co2|barometric-pressure|oxygen|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="25996" PostTypeId="2" ParentId="25953" CreationDate="2024-02-23T00:30:59.223" Score="3" Body="&lt;p&gt;The answer is yes, but the differences, if you mean tangible differences in composition and nature of the melt and not just primary melt source, are  minor and technical. This is a complex subject but I will try and give a reasonably accurate general answer.&lt;/p&gt;&#xA;&lt;p&gt;Melts in arc settings are dominantly produced by flux melting of the mantle wedge overlying a subducting slab, with variable melt inputs from the slab itself and the sediments that slab has carried down with it. We now know, and there is general consensus among igneous petrologists, that the flux for mantle melting is provided by a mixture (supercritical fluid) of melt and fluids derived from the subducting slab and associated sediments, and the ratio of these two components varies from system to system as we would expect in nature. There are, however, rare cases where it appears the majority of a melt was sourced from the subducting oceanic basalt slab (adakites), however in most cases the majority of the melt is primitive mantle derived stuff.&lt;/p&gt;&#xA;&lt;p&gt;In back-arc/extensional settings the melt is typically (assuming passive rifting here) derived from adiabatically upwelling asthenospheric mantle that is reacting to thinning of the overlying crust. This might at first glance appear to indicate that both arc and extensional magmas are deriving partial melts from essentially the same source (lets not discuss mantle heterogeneity here). However, the addition of that flux component to the arc magma changes the composition of the melt ever so slightly (your feelings about scale here might differ), and this can be observed through isotopic and trace element analysis. Indeed, we know that the slab is affecting our melt for that very reason: we can see it in the chemistry.&lt;/p&gt;&#xA;&lt;p&gt;In fact, there appears to be a great deal of variation in magma chemistry as you move away from or towards the arc as well as along an individual arc, which reflects the influence of fluids derived from a subducting slab and the thermal structure of the subduction zone and slab. &lt;a href=&quot;https://www.frontiersin.org/articles/10.3389/feart.2022.1055255/full&quot; rel=&quot;nofollow noreferrer&quot;&gt;Here&lt;/a&gt; is a recent paper on that.&lt;/p&gt;&#xA;&lt;p&gt;Further, one setting can effect the other. Depleted asthenospheric mantle from the back-arc extensional setting can be cycled into the sub-arc/mantle wedge melting region and affect the chemistry of melts as well as the volcanism in the arc. See &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/S0012821X19302766&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt; for some discussion of how this might work.&#xA;It has also been shown that fluids from the subduction zone can be incorporated in, and affect, the chemistry of back-arc extension related melts. The proximity of the spreading center/zone of extension to the subduction zone/sub-arc melting region controls how much of an influence the subduction zone has on the magma. See &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/JB090iB13p11431?casa_token=P26SrTFGWjUAAAAA:S7ap_CfzELXLateFXuiU6mmT7Oh4jqM2f3SsOrXPxZxXCYvUHcbKtaXXaLUcW4cUUMyBnOVMJ68MDRs&quot; rel=&quot;nofollow noreferrer&quot;&gt;this paper&lt;/a&gt; for a bit on that from a case-study point of view. This is mostly the result of viscous mantle flow, although that is an immense simplification and there is significant room for nuance there.&lt;/p&gt;&#xA;&lt;p&gt;If you would like specifics on what exactly the chemical differences are between melts in these two settings the sources I've provided are a good place to look. However, I am also happy to provide a more detailed/less simplified response that includes those aspects as well.&lt;/p&gt;&#xA;" OwnerUserId="29921" LastActivityDate="2024-02-23T00:30:59.223" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25997" PostTypeId="1" CreationDate="2024-02-23T12:54:20.253" Score="1" ViewCount="55" Body="&lt;p&gt;My team developed a method to detect PM2.5 hotspots in a city using mobile sensor measurements. Now, we want to simulate a validation dataset to test our method. We want simulated data so that we can set a 'ground truth' for where hotspots are located, and thus compute accuracy metrics.&lt;/p&gt;&#xA;&lt;p&gt;Does anyone know a free software for this? I imagine it takes pollution source locations, wind speed, etc. as inputs, then outputs a time series of pollution values in a defined region.&lt;/p&gt;&#xA;&lt;p&gt;&lt;strong&gt;Already tried:&lt;/strong&gt;&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://cerea.enpc.fr/polyphemus/index.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;Polyphemus&lt;/a&gt;: looks good, but apparently the software packages have not been updated in 13 years&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://en.wikipedia.org/wiki/List_of_atmospheric_dispersion_models&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikipedia&lt;/a&gt;: has a list of atmospheric dispersion models, but it is unclear which are readily available as software&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="30534" LastActivityDate="2024-03-24T17:07:35.890" Title="Free software for simulating the dispersion of air pollution" Tags="|air-pollution|software|simulation|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="25998" PostTypeId="2" ParentId="25997" CreationDate="2024-02-23T16:08:24.580" Score="1" Body="&lt;p&gt;In addition to those listed in @f.thorpe's comment (I want to at least point to him to give credit for his choices, which are my first choices too), some other readily available models include:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.epa.gov/cameo/aloha-software&quot; rel=&quot;nofollow noreferrer&quot;&gt;ALOHA&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.epa.gov/scram/air-quality-dispersion-modeling-alternative-models&quot; rel=&quot;nofollow noreferrer&quot;&gt;A bunch of alternative EPA models.&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.flexpart.eu/&quot; rel=&quot;nofollow noreferrer&quot;&gt;FLEXPART&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://src.com/&quot; rel=&quot;nofollow noreferrer&quot;&gt;CALPUFF&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="704" LastActivityDate="2024-02-23T16:08:24.580" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="25999" PostTypeId="2" ParentId="25992" CreationDate="2024-02-23T18:49:08.560" Score="2" Body="&lt;p&gt;Yes, the Coriolis effect does impact some of the oceanic currents. One related phenomenon is the &lt;em&gt;western intensification&lt;/em&gt; that is leading to the &lt;em&gt;western boudaries currents&lt;/em&gt;.&lt;/p&gt;&#xA;&lt;p&gt;You can find more on wikipedia : &lt;a href=&quot;https://en.wikipedia.org/wiki/Boundary_current#Western_intensification&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Boundary_current#Western_intensification&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;An eastern-flowing current (~ like a jet current) will also form if there is a significant extension of the eastern boundary ( i.e. a continental barrier), and will be located at the same latitude than the land's extension.&lt;/p&gt;&#xA;&lt;p&gt;If I remember correctly, the Stommels &amp;amp; Arons model as explained in &lt;em&gt;Ocean Circulation Theory&lt;/em&gt; by Pedlosky explains it well (&lt;a href=&quot;https://link.springer.com/book/10.1007/978-3-662-03204-6?utm_medium=referral&amp;amp;utm_source=google_books&amp;amp;utm_campaign=3_pier05_buy_print&amp;amp;utm_content=en_08082017&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://link.springer.com/book/10.1007/978-3-662-03204-6?utm_medium=referral&amp;amp;utm_source=google_books&amp;amp;utm_campaign=3_pier05_buy_print&amp;amp;utm_content=en_08082017&lt;/a&gt;).&lt;/p&gt;&#xA;" OwnerUserId="21235" LastEditorUserId="21235" LastEditDate="2024-02-27T09:53:32.967" LastActivityDate="2024-02-27T09:53:32.967" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26000" PostTypeId="2" ParentId="25976" CreationDate="2024-02-23T20:51:32.030" Score="1" Body="&lt;p&gt;As you said, latent heat is the heat stocked into the water vapour and thus transported by the winds. You can see great example of how latent heat transport may influence temperatures with Foehn-like winds (&lt;a href=&quot;https://en.wikipedia.org/wiki/Foehn_wind&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://en.wikipedia.org/wiki/Foehn_wind&lt;/a&gt;) creating warm region after having crossed mountain ranges : the moist rising air heats up (and dries out thanks to rain) faster than the dry subsiding air cools down, so the latent heat initially stocked in the water vapour turns into sensible heat.&lt;/p&gt;&#xA;" OwnerUserId="21235" LastActivityDate="2024-02-23T20:51:32.030" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26001" PostTypeId="1" CreationDate="2024-02-24T07:03:58.207" Score="1" ViewCount="59" Body="&lt;p&gt;Why is it that negative lightning leaders step much more frequently compared to positive leaders&#xA;Unfortunately,the only paper on it I could find was paywalled: &lt;em&gt;&lt;a href=&quot;https://iopscience.iop.org/article/10.1088/1361-6463/aca103&quot; rel=&quot;nofollow noreferrer&quot;&gt;Toward a theory of 'stepped-leaders' in lightning&lt;/a&gt;&lt;/em&gt; (DOI 10.1088/1361-6463/aca103).&lt;/p&gt;&#xA;" OwnerUserId="30498" LastEditorUserId="30498" LastEditDate="2024-02-26T23:40:54.777" LastActivityDate="2024-02-26T23:40:54.777" Title="Why do negative and positive leaders behave differently" Tags="|atmosphere|lightning|electromagnetism|" AnswerCount="0" CommentCount="9" ContentLicense="CC BY-SA 4.0" />
  <row Id="26002" PostTypeId="5" CreationDate="2024-02-24T07:36:11.347" Score="0" Body="&lt;p&gt;Erupted magma due to volcanic activity&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-02-25T08:06:22.463" LastActivityDate="2024-02-25T08:06:22.463" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26003" PostTypeId="4" CreationDate="2024-02-24T07:36:11.347" Score="0" Body="Erupted magma due to volcanic activity" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-02-26T20:38:16.373" LastActivityDate="2024-02-26T20:38:16.373" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26004" PostTypeId="5" CreationDate="2024-02-24T07:37:39.803" Score="0" Body="&lt;p&gt;A water body (ocean) that separates North and South America from Africa and Europe.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-02-26T05:26:19.560" LastActivityDate="2024-02-26T05:26:19.560" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26005" PostTypeId="4" CreationDate="2024-02-24T07:37:39.803" Score="0" Body="A water body (ocean) that separates North and South America from Africa and Europe. " OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-02-26T05:09:41.490" LastActivityDate="2024-02-26T05:09:41.490" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26006" PostTypeId="5" CreationDate="2024-02-24T07:38:47.747" Score="0" Body="&lt;p&gt;A mineral is an element or chemical compound that is normally crystalline and has been formed by geological processes.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-02-26T05:28:24.633" LastActivityDate="2024-02-26T05:28:24.633" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26007" PostTypeId="4" CreationDate="2024-02-24T07:38:47.747" Score="0" Body="A mineral is an element or chemical compound that is normally crystalline and has been formed by geological processes." OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-02-25T13:25:05.527" LastActivityDate="2024-02-25T13:25:05.527" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26008" PostTypeId="2" ParentId="9620" CreationDate="2024-02-25T10:11:49.203" Score="1" Body="&lt;p&gt;A big part of this is that lightning strikes are easy to protect against using lightning rods on buildings and metal framing with conductive tires on cars&lt;/p&gt;&#xA;&lt;p&gt;In terms of fatalities, the truth is lightning is usually too brief to cause significant  heating of the body and the very high voltage generally prevents fibrillation&lt;/p&gt;&#xA;" OwnerUserId="30498" LastActivityDate="2024-02-25T10:11:49.203" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26009" PostTypeId="2" ParentId="12003" CreationDate="2024-02-25T16:02:21.000" Score="2" Body="&lt;p&gt;I’m just now learning about velum clouds, but have been familiar with pileus clouds for a while. It seems to me that the main difference is size if I’m understanding correctly. That doesn’t really help your question, but I mainly wanted to address the ending of your post.&lt;/p&gt;&#xA;&lt;p&gt;When an updraft occurs, this essentially acts as an obstruction in the horizontal flow. When this reaches high enough in the atmosphere to perturb a stable, near saturated environment in the upper levels, that can lead to lenticulars.&lt;/p&gt;&#xA;&lt;p&gt;While the trigger is vastly different, a mountain vs a cloud, the mechanical mechanism is almost identical. Your inducing wave like motion to a nearly saturated layer and the rising condenses, the lowering evaporates.&lt;/p&gt;&#xA;&lt;p&gt;Being in a few weather groups on Facebook, you see a lot of people post from flat areas (relatively) and wondering how they are seeing lenticulars… absent of large cumulonimbus updrafts or mountains, you can also get them downwind of mountains, for several hundred miles, or even an atmospheric trigger. Two airmasses with different densities interacting and sending some of that energy/motion upwards is all it takes.&lt;/p&gt;&#xA;&lt;p&gt;As for the pileus/velum debate, moving forward, I’ll hold off on using “velum” unless the cloud covers an area bigger than the parent cloud. But that’s just an interpretation.&lt;/p&gt;&#xA;" OwnerUserId="31544" LastActivityDate="2024-02-25T16:02:21.000" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26010" PostTypeId="2" ParentId="9620" CreationDate="2024-02-25T21:50:29.550" Score="0" Body="&lt;p&gt;The fires lightning starts cause enormous damage and harms including significant loss of life. Lightning is the Proximate Cause - what &lt;em&gt;starts&lt;/em&gt; a fire - but is not what directly does the damage and harms. Other factors determine how damaging.&lt;/p&gt;&#xA;&lt;p&gt;Dry lightning storms during periods of high wildfire danger are the greatest danger and often start fires that reach great size and intensity. 2019 Bushfires in Australia included fires started by dry storms, one of which burned around my home (saved by firefighters) but burned down many other homes and took human lives.&lt;/p&gt;&#xA;" OwnerUserId="18145" LastActivityDate="2024-02-25T21:50:29.550" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26011" PostTypeId="5" CreationDate="2024-02-26T07:00:59.853" Score="0" Body="&lt;p&gt;CO2 is the chemical formula for the molecule carbon dioxide, which consists of carbon and oxygen.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-02-27T09:23:33.230" LastActivityDate="2024-02-27T09:23:33.230" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26012" PostTypeId="4" CreationDate="2024-02-26T07:00:59.853" Score="0" Body="&#xD;&#xA;CO2 is the chemical formula for the molecule carbon dioxide, which consists of carbon and oxygen." OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-02-27T09:24:00.943" LastActivityDate="2024-02-27T09:24:00.943" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26013" PostTypeId="5" CreationDate="2024-02-26T07:02:35.533" Score="0" Body="&lt;p&gt;The Anthropocene Epoch represents an informal designation within the geological time scale, employed to delineate the contemporary era in Earth's chronology.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-02-26T20:38:22.430" LastActivityDate="2024-02-26T20:38:22.430" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26014" PostTypeId="4" CreationDate="2024-02-26T07:02:35.533" Score="0" Body="&#xD;&#xA;The Anthropocene Epoch represents an informal designation within the geological time scale, employed to delineate the contemporary era in Earth's chronology." OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-02-26T20:38:09.693" LastActivityDate="2024-02-26T20:38:09.693" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26015" PostTypeId="1" AcceptedAnswerId="26016" CreationDate="2024-02-26T14:32:34.843" Score="1" ViewCount="31" Body="&lt;p&gt;In Greece, the daily limit for PM10 is the 50 μg/m3 and the annual limit is 40 μg/m3. I think that WHO have proposed lower limits although these have not proposed adopted.&lt;/p&gt;&#xA;&lt;p&gt;But, there is no hourly limit for the concentration of PM10. PM10 is a very important pollutant with various effects to human health, so I would like to ask if there are rules in other countries or other proposal about establishing hourly limits.&lt;/p&gt;&#xA;" OwnerUserId="30273" LastActivityDate="2024-02-26T19:04:17.500" Title="PM10 hourly limits" Tags="|air-pollution|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="26016" PostTypeId="2" ParentId="26015" CreationDate="2024-02-26T16:49:52.943" Score="2" Body="&lt;p&gt;There are no hourly standards for particulate matter in the USA.  However, sensors and metrics are displayed hourly on websites so that the public can assess their near-real-time exposure and act accordingly.  Air is extremely dynamic, so a single hourly value does not necessarily represent typical conditions in the area.  A longer-term value (or average) is needed to assess what people are breathing regularly.  The main point of a regulatory health-based standard is to be able to compel industrial sources to enact controls or some other limitation on their emissions, but we cannot attribute a single hourly value of particulate matter to a particular facility and then expect them to change their practices because of it.  Particulate matter comes from a variety of source categories and is quite common, unlike many toxics pollutants which can only be emitted from very particular types of sources (and therefore be attributed to those sources when they are monitored at high levels).  Furthermore, regulatory health standards are usually enforced over a longer time period (e.g. annually) by using the average of the highest hourly (or daily) values over that year.  So, one hourly (or daily) value above the standard does not equate to an exceedance of the standard.&lt;/p&gt;&#xA;&lt;p&gt;In the USA, the only pollutants with an hourly regulatory standard (e.g. in the &lt;a href=&quot;https://www.epa.gov/criteria-air-pollutants/naaqs-table&quot; rel=&quot;nofollow noreferrer&quot;&gt;NAAQS&lt;/a&gt;) are Carbon Monoxide, Nitrogen Dioxide, and Sulfur Dioxide.  These are gaseous pollutants that can be measured at sub-hourly intervals.  However, the benchmark for particulate matter measurements uses a filter.  So, measuring particulate data hourly would require a new filter to be set every hour, which is impractical.  In fact, many PM2.5 regulatory monitors only measure once every 6th day, so that operators have time to go change filters for all monitors across the network.  The health effects of particulate matter will also take a long time to become a problem because it is not hazardous like other toxic pollutants can be.  Some pollutants can literally be fatal (or cancer causing) within an hour of exposure while typical particulate matter concentrations need to recur for years of your life before acute health problems would typically occur.&lt;/p&gt;&#xA;&lt;p&gt;Regarding PM10, it is a rather old metric for particulate matter regulatory standards.  In general, fine particulate matter (e.g. PM2.5) is more of a health concern.  In fact, ultra-fine particles (e.g. PM1.0) is of most concern since the particles can go deep into the lungs.  I don't think the USA plans to update PM10 standards, but PM2.5 standards are &lt;a href=&quot;https://www.epa.gov/pm-pollution/national-ambient-air-quality-standards-naaqs-pm#:%7E:text=%E2%80%8B%20EPA%20is%20setting%20the,with%20the%20available%20health%20science.&quot; rel=&quot;nofollow noreferrer&quot;&gt;currently being revised&lt;/a&gt; to a lower level.&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2024-02-26T19:04:17.500" LastActivityDate="2024-02-26T19:04:17.500" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26017" PostTypeId="2" ParentId="25992" CreationDate="2024-02-26T19:16:47.590" Score="5" Body="&lt;p&gt;Yes, a major factor in ocean currents is the &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/B9780750645522100071#s0120&quot; rel=&quot;noreferrer&quot;&gt;geostrophic balance&lt;/a&gt;, where Coriolis forces balance pressure gradient forces.  In the northern hemisphere, Coriolis-driven currents flow clockwise around areas of high pressure, such as where the sea surface height is elevated.  This sustains currents like the subtropical north Atlantic gyre.&lt;/p&gt;&#xA;&lt;p&gt;The Coriolis effect plays into several other processes, such as the &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/B9780750645522100071#s0180&quot; rel=&quot;noreferrer&quot;&gt;Sverdrup balance&lt;/a&gt;, which contributes to western boundary currents, and the more general process of &lt;a href=&quot;https://www.sciencedirect.com/science/article/pii/B9780750645522100071#s0090&quot; rel=&quot;noreferrer&quot;&gt;Ekman transport&lt;/a&gt;.  Convergent or divergent Ekman transport, driven by wind stress curl, produces sea surface height anomalies (by &amp;quot;piling up&amp;quot;, or moving apart, water at the surface) and thus geostrophic currents.&lt;/p&gt;&#xA;" OwnerUserId="26713" LastActivityDate="2024-02-26T19:16:47.590" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26018" PostTypeId="2" ParentId="25990" CreationDate="2024-02-26T23:53:02.783" Score="1" Body="&lt;p&gt;We definitely have +2 and +3 ions bonded within the same type of site. And it's not just iron; magnesium can become involved among the +2 ions and aluminum among the +3 ions. As for whether they are &amp;quot;lattice bound&amp;quot; or not, I would say that those multiply charged ions are tighly bound into a lattice structure that covers their part of the overall layered mineral structure, and only some weakly bound alkali metal ions elsewhere, between the layers, &amp;quot;look&amp;quot; interstitial.&lt;/p&gt;&#xA;&lt;p&gt;Glauconite has a &lt;a href=&quot;https://en.wikipedia.org/wiki/Mica&quot; rel=&quot;nofollow noreferrer&quot;&gt;mica&lt;/a&gt;-group phyllosilicate structure and the (nominal) &lt;a href=&quot;https://en.wikipedia.org/wiki/Glauconite&quot; rel=&quot;nofollow noreferrer&quot;&gt;chemical formula&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{(K,Na)\color{blue}{(Fe,Al,Mg)2}\color{brown}{(Si,Al)4O10}\color{blue}{(OH)2}}.$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;where I mark parts of the formula is different colors for the purpose of understanding this structure.&lt;/p&gt;&#xA;&lt;p&gt;Mica, as readers of this question thread probably know, consists of layers that are weakly bound by interlayer ions. The black ions noted above, which are akali metals carrying one positive charge per ion (&lt;span class=&quot;math-container&quot;&gt;$\ce{Na^+,K^+}$&lt;/span&gt;), are the interlayer ions. It is these interlayer iins, which are only weakly bound and give micas their sheetlike structure and low Mohs hardness, that most qualify as &amp;quot;interstitail&amp;quot;; the more strongly bound rest of the structure is more arguably &amp;quot;lattice-bound&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;The brown part of the formula is the silicate sheets that form the outer parts of the layers, like buns of a burger. These are polymrized tetrahedral silicate networks in which some of the silicon (&lt;span class=&quot;math-container&quot;&gt;$\ce{Si^{4+}}$&lt;/span&gt;) may be replaced by aluminum (&lt;span class=&quot;math-container&quot;&gt;$\ce{Al^{3+}}$&lt;/span&gt;), All of these are bound tetrahedrally to oxygen (&lt;span class=&quot;math-container&quot;&gt;$\ce{O^{2-}}$&lt;/span&gt;), with three of the oxygen atoms bonded to each silicon serving as bridges within the &amp;quot;bun&amp;quot; and the fourth oxygen open for bonding to the &amp;quot;meat&amp;quot; inside.&lt;/p&gt;&#xA;&lt;p&gt;Which brings us to the meat of the burger, indicated in blue. The open oxygen valences from the silicate layers are bonded to the multiply charged ions indicated in blue, which are additionally bonded to hydroxide ions (&lt;span class=&quot;math-container&quot;&gt;$\ce{OH^-}$&lt;/span&gt;) also shown in blue. The metals ions are octahedrally coordinated and may be any combination of those indicated in the formula: &lt;span class=&quot;math-container&quot;&gt;$\ce{Fe^{2+},Fe^{3+},Al^{3+},Mg^{2+}}$&lt;/span&gt;. The mixed charges come from the fact that the two positive ions have to balance out with the net negative charge in the rest of the structure, and that charge balance can't be done wuth one type of ion charge.&lt;/p&gt;&#xA;&lt;p&gt;Let's look at the charge balance, recalling the chemical formula above:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{(K,Na)\color{blue}{(Fe,Al,Mg)2}\color{brown}{(Si,Al)4O10}\color{blue}{(OH)2}}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;The &amp;quot;black&amp;quot;, interlayer alkali metal iobs contribute one positive charge per site. The &amp;quot;brown&amp;quot; or &amp;quot;bun&amp;quot; layer can contribute anywhere from four to eight negative charges per &lt;span class=&quot;math-container&quot;&gt;$\ce{(Si,Al)4O10}$&lt;/span&gt; unit, with four corresponding to all silicon and eight to all aluminum; in practice the tetrahedrally bound atoms are mostly silicon and thus this figure is really between four (&lt;span class=&quot;math-container&quot;&gt;$\ce{Si4O10^{4-}}$&lt;/span&gt;) and five ((&lt;span class=&quot;math-container&quot;&gt;$\ce{AlSi3O10^{5-}}$&lt;/span&gt;)). The hydroxide ions within the &amp;quot;meat&amp;quot; add two more negative charges per formula unit. Adding all this up we find that the two metal ion sites per formula unit in the &amp;quot;meat&amp;quot; must add up to between five and six positive charges. Thus the mixture of +2 and +3 ions, with the latter becoming more predominant if the &amp;quot;buns&amp;quot; are relatively rich in aluminum. Given the ion size constraints to fit in the mica structure and which metallic ions are most common in the crust, we will end up with some combination of primarily iron, aluminum and magnesium satisfying this mixed charge requirement.&lt;/p&gt;&#xA;" OwnerUserId="20607" LastEditorUserId="20607" LastEditDate="2024-02-27T00:40:20.117" LastActivityDate="2024-02-27T00:40:20.117" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26020" PostTypeId="1" CreationDate="2024-02-28T08:50:01.070" Score="3" ViewCount="32" Body="&lt;p&gt;I understand plate tectonics at approximately the level of the Wikipedia entry, but I have not idea what factors determine the particular locations of the plate boundaries.&lt;/p&gt;&#xA;&lt;p&gt;Do we have a model for the processes that determine this? Is it completely random (for example, sites impacted later by large meteorites stay molten longer and end up as boundaries, just for a quick hypothesis off the top of my head) or is it determined by some predictable process (pre-established stable subsurface magma currents, perhaps)?&lt;/p&gt;&#xA;&lt;p&gt;Are all final shapes equally likely? If I was imagining an Earth-like planet whose plate boundaries looked like Homer Simpson is that as plausible as any other specific (if meaningless) jumble of lines?&lt;/p&gt;&#xA;" OwnerUserId="770" LastActivityDate="2024-02-28T08:50:01.070" Title="What determines the shape of tectonic plates?" Tags="|plate-tectonics|tectonics|planetary-formation|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26021" PostTypeId="2" ParentId="7244" CreationDate="2024-02-28T15:20:12.653" Score="1" Body="&lt;p&gt;It's the Black Belt Prairie. NASA's Earth Observatory featured it:&lt;br /&gt;&#xA;&lt;a href=&quot;https://earthobservatory.nasa.gov/images/92321/black-belt-prairie&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://earthobservatory.nasa.gov/images/92321/black-belt-prairie&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="31557" LastActivityDate="2024-02-28T15:20:12.653" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="26022" PostTypeId="1" CreationDate="2024-03-01T06:12:30.873" Score="1" ViewCount="39" Body="&lt;p&gt;i am trying to find out moisture divergence using metpy divergence module and i used&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;qu12=q3b*u3b&#xA;qv12=q3b*v3b&#xA;HMD12 = mpcalc.divergence(qu12, qv12)&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;here qu12 ,qv12 are 4d xarray data array, and i got the moisture divergence correctly using this. Usually we need to give dx=lon,dy=lat in the last line of this code but when i add this i was getting the error&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;&amp;gt; too many indices for array: array is 2-dimensional, but 4 were indexed&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;since i was getting the divergence without giving this i didn't paid attention to this error. But now I need to find the moisture divergence for another xarray. Now i am doing it for a dictionary with years being the keys&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;HMD = {}&#xA;&#xA;    for year in [2012, 2018, 2019]:&#xA;        # Get the resampled dataset for the current year&#xA;        resampled_ds = resampled_data[year]&#xA;        # Slice latitude and longitude ranges&#xA;        # Select latitude values within the desired range(8-12, 75-77)&#xA;        lat_range = resampled_ds['latitude'].where((resampled_ds['latitude'] &amp;gt;= 8) &amp;amp; (resampled_ds['latitude'] &amp;lt;= 12), drop=True)&#xA;        sliced_ds = resampled_ds.sel(latitude=lat_range, longitude=slice(75, 78))&#xA;        # Calculate the moisture flux components&#xA;        qu_l = (sliced_ds['Q'] * sliced_ds['U'])&#xA;        qv_l = (sliced_ds['Q'] * sliced_ds['V'])&#xA;        # Compute the grid deltas (dx, dy) in meters&#xA;        dx, dy = mpcalc.lat_lon_grid_deltas(sliced_ds['longitude'], sliced_ds['latitude'])&#xA;        # Compute the divergence of the moisture flux&#xA;        HMD[year] = mpcalc.divergence(qu_l, qv_l, dx=dx, dy=dy)&#xA;        HMD[year] = HMD&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;here also qu_l and qv_l are 4d xarrays(lon,lat,level,time) same as qu12 the only difference is for qu12 the lat and lon are in float32 and for qu_l it is in float64. can any one tell why it works for qu12 (4darray) but not for another 4d array qu_l?&lt;/p&gt;&#xA;" OwnerUserId="22424" LastActivityDate="2024-03-01T06:12:30.873" Title="metpy divergence module array indexing error" Tags="|meteorology|atmosphere|python|data-analysis|metpy|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26024" PostTypeId="2" ParentId="24127" CreationDate="2024-03-02T03:45:47.950" Score="1" Body="&lt;p&gt;Shadows in the atmosphere are pretty common.  Light that is being scattered in the non-shadow area makes the atmosphere brighter, and the shadow (being shielded from the sun) is darker.&#xA;Look up mountain shadows, or check out this link&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://physics.stackexchange.com/questions/264869/what-is-this-shadow-being-cast-upon&quot;&gt;Mountain Shadow&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="31567" LastActivityDate="2024-03-02T03:45:47.950" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26025" PostTypeId="5" CreationDate="2024-03-02T07:12:13.020" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2024-03-02T07:12:13.020" LastActivityDate="2024-03-02T07:12:13.020" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26026" PostTypeId="4" CreationDate="2024-03-02T07:12:13.020" Score="0" Body="Rainfall refers to a meteorological phenomenon and the most commonly occurring form of precipitation." OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-03-07T23:56:22.353" LastActivityDate="2024-03-07T23:56:22.353" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26027" PostTypeId="5" CreationDate="2024-03-02T07:13:16.103" Score="0" Body="&lt;p&gt;Snow consists of fine ice crystals and is the most common form of solid precipitation.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-03-03T20:49:06.310" LastActivityDate="2024-03-03T20:49:06.310" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26028" PostTypeId="4" CreationDate="2024-03-02T07:13:16.103" Score="0" Body="Snow consists of fine ice crystals and is the most common form of solid precipitation." OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-03-03T20:49:17.420" LastActivityDate="2024-03-03T20:49:17.420" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26029" PostTypeId="1" AcceptedAnswerId="26039" CreationDate="2024-03-02T22:19:40.327" Score="2" ViewCount="40" Body="&lt;p&gt;I am looking for ways to present real-time meteorological and pollutant data in a website. Searching the internet for pollutant data, I've found interesting sites for &lt;a href=&quot;https://dublincityairandnoise.ie/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dublin&lt;/a&gt;, &lt;a href=&quot;https://app.thermiair.gr/dashboard&quot; rel=&quot;nofollow noreferrer&quot;&gt;Thermi&lt;/a&gt; (in Greece), and &lt;a href=&quot;https://www.airqualityengland.co.uk/local-authority/?la_id=86&quot; rel=&quot;nofollow noreferrer&quot;&gt;London&lt;/a&gt; (if I understand correctly, the measurements from all of England are actually presented)&lt;/p&gt;&#xA;&lt;p&gt;Finding those, I would like to ask if you know of any other sites from municipalities that present real time data about air pollution and meteorological parameters. (If you have data from states or country, I would like to know, but I would prefer it from municipalities)&lt;/p&gt;&#xA;" OwnerUserId="30273" LastEditorUserId="6298" LastEditDate="2024-03-04T09:36:23.297" LastActivityDate="2024-03-05T15:00:38.450" Title="Municipal websites with air pollution information" Tags="|air-pollution|open-data|" AnswerCount="1" CommentCount="7" ContentLicense="CC BY-SA 4.0" />
  <row Id="26031" PostTypeId="5" CreationDate="2024-03-03T18:04:35.057" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2024-03-03T18:04:35.057" LastActivityDate="2024-03-03T18:04:35.057" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26032" PostTypeId="4" CreationDate="2024-03-03T18:04:35.057" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2024-03-03T18:04:35.057" LastActivityDate="2024-03-03T18:04:35.057" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26034" PostTypeId="5" CreationDate="2024-03-04T06:02:19.417" Score="0" Body="&lt;p&gt;Glacially covered continental mass in the Southern Hemisphere.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-03-07T23:56:34.113" LastActivityDate="2024-03-07T23:56:34.113" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26035" PostTypeId="4" CreationDate="2024-03-04T06:02:19.417" Score="0" Body="Glacially covered continental mass in the Southern Hemisphere." OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-03-06T09:28:49.047" LastActivityDate="2024-03-06T09:28:49.047" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26036" PostTypeId="1" AcceptedAnswerId="26037" CreationDate="2024-03-04T10:19:10.003" Score="3" ViewCount="170" Body="&lt;p&gt;In many introductory geology courses, a great deal of time is spent on the historical composition of earth's atmosphere: the great oxygenation event, oxygen maximum during the carboniferous, ups and downs for the CO2 trend...&lt;/p&gt;&#xA;&lt;p&gt;The graphs supporting those discussions always (according to my memory) show the fractional composition of the atmosphere. But given that for many of the phenomena one wants to explain with this composition trend it would rather be the partial pressures or total mass of each of the composing gases that would be relevant, my question is whether there is (in the scientific literature) an account of the total pressure and / or the total mass of earth's atmosphere on geological time scales?&lt;/p&gt;&#xA;" OwnerUserId="22315" LastActivityDate="2024-03-04T13:32:46.807" Title="The total pressure / total mass of earth's atmosphere on geological time scales" Tags="|geology|atmosphere|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26037" PostTypeId="2" ParentId="26036" CreationDate="2024-03-04T13:32:46.807" Score="3" Body="&lt;p&gt;There are few studies of paleobarometry, but to my knowledge at least three different proxies have been used to infer past atmospheric pressures, and they pretty much agree:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;strong&gt;Fossil raindrop imprints&lt;/strong&gt;. &lt;a href=&quot;https://doi.org/10.1038/nature10890&quot; rel=&quot;nofollow noreferrer&quot;&gt;Som et al. (2012)&lt;/a&gt; used such imprints found in tuffs of the Ventersdorp Supergroup (South Africa), dated around 2.7 Ga, to determine the terminal velocity of raindrops and, finally, surface air density. They estimate that it was, at that time, less than twice modern levels (2.3 kg m&lt;sup&gt;−3&lt;/sup&gt; compared 1.2 kg m&lt;sup&gt;−3&lt;/sup&gt;).&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;&lt;span class=&quot;math-container&quot;&gt;$\ce{N2}/\ce{^36Ar}$&lt;/span&gt; ratio&lt;/strong&gt;. &lt;a href=&quot;https://doi.org/10.1126/science.1240971&quot; rel=&quot;nofollow noreferrer&quot;&gt;Marty et al. (2013)&lt;/a&gt; used fluid inclusions trapped in three different Archean hydrothermal quartz samples to determine the past partial pressure of nitrogen and carbon dioxide, finding &lt;span class=&quot;math-container&quot;&gt;$P_{\ce{N2}} \leq 1.1$&lt;/span&gt; bar and &lt;span class=&quot;math-container&quot;&gt;$P_{\ce{CO2}} \leq 0.7$&lt;/span&gt; bar.&lt;/li&gt;&#xA;&lt;li&gt;&lt;strong&gt;Lava flow vesicle size&lt;/strong&gt;. &lt;a href=&quot;https://doi.org/10.1038/ngeo2713&quot; rel=&quot;nofollow noreferrer&quot;&gt;Som et al. (2016)&lt;/a&gt; used this proxy in a basaltic lava flow from the Pilbara Craton (Australia), emplaced around 2.7 Ga, finding that the late Archaean atmospheric pressure was likely less than 0.5 bar.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;But these are only a few data points giving a snapshot of a particular moment in time. I'm not aware that there has been efforts to reconstruct a more comprehensive paleobarometric record.&lt;/p&gt;&#xA;" OwnerUserId="18081" LastActivityDate="2024-03-04T13:32:46.807" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="26038" PostTypeId="1" CreationDate="2024-03-04T14:06:59.860" Score="1" ViewCount="39" Body="&lt;p&gt;Why do we see a bipartite cliff,i.e., a vertical top portion and a slanted bottom portion at the edge of a mesa or butte? I came to know from the internet that the top portion is the hard caprock And the bottom is composed of softer Rock which is more easily eroded by the wind. But why is the cap Rock have vertical edges but the underlying portion have a slanted edge? Why can't the wind erode that cone of soft rock? Is the outer cone belt entirely made up of caprock material with the original soft rock lying inside?&#xA;Is it protected by the talus deposits of the caprock cliff? I later found that the caprock protects the underlying soft rock from being eroded away. But how so? Same for hoodoos(called 'demoiselles' in my textbook). The wind can erode from the side, right? I suspect eroding the soft rock from the top is more effective, but can't find the logic behind it. Please note that I am a high school student(grade 10) trying to understand this for an hour. So a simple yet satisfying answer would be very useful.&lt;/p&gt;&#xA;" OwnerUserId="31576" LastEditorUserId="31576" LastEditDate="2024-03-05T05:30:26.590" LastActivityDate="2024-03-05T18:27:11.747" Title="How does the caprock of aeolian landforms such as mesas, buttes and hoodoos protect the underlying soft rock?" Tags="|geology|wind|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26039" PostTypeId="2" ParentId="26029" CreationDate="2024-03-05T07:48:09.687" Score="2" Body="&lt;p&gt;I'm not very familiar with air quality monitoring website maps in Europe, but in the USA there are many of them.  However, most only show pollutants being monitored, and do not include meteorology.  There are some that include both, since many air quality monitor stations also include some meteorological instrumentation.  Here are a few examples of sites that include both:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://www.arb.ca.gov/aqmis2/map_pages/gmap.php&quot; rel=&quot;nofollow noreferrer&quot;&gt;California&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://desaqmonitoring.clarkcountynv.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Nevada&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://aqi.oregon.gov/&quot; rel=&quot;nofollow noreferrer&quot;&gt;Oregon&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://tceq.maps.arcgis.com/apps/webappviewer/index.html?id=ab6f85198bda483a997a6956a8486539&quot; rel=&quot;nofollow noreferrer&quot;&gt;Texas&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://enviwa.ecology.wa.gov/home/map&quot; rel=&quot;nofollow noreferrer&quot;&gt;Washington&lt;/a&gt;&lt;/li&gt;&#xA;&lt;li&gt;&lt;a href=&quot;https://njdep.maps.arcgis.com/apps/webappviewer/index.html?id=76194937cbbe46b1ab9a9ec37c7d709b&quot; rel=&quot;nofollow noreferrer&quot;&gt;New Jersey&lt;/a&gt;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://www.airnowtech.org/index.cfm?page=login&quot; rel=&quot;nofollow noreferrer&quot;&gt;AirNow Tech Navigator&lt;/a&gt; is the best site, since it pulls in weather data from the National Weather Service as well as satellite data and other sources of information that you can plot alongside the air quality data.  It also allows you to do HYSPLIT trajectories and wind roses on the fly.  However, it requires that you are a member of an agency, company, or university on their list in order to get an account.  Below is an example of the type of map plot you can make with the tool, from &lt;a href=&quot;https://apps.ecology.wa.gov/publications/documents/1902004.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;.  Though, the site doesn't show &amp;quot;current&amp;quot; air quality.  Instead it lets you pick the date/time to within a few hours of current (or maybe &amp;quot;yesterday&amp;quot;).&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/f9dvR.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/f9dvR.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;em&gt;24-hour HYSPLIT back trajectories at 50 (green), 500 (blue), and 2000 (red) meter starting heights on September 6, 2017 for Yakima. Four back trajectories are shown starting at 4 am, 10 am, 4 pm, and 10 pm PST. HMS-detected hot-spots are shown as red triangles. The background layer is Aqua/MODIS imagery (~2 pm LT). The wind barbs and hourly PM2.5 shown are monitored values at 2 PM PST.&lt;/em&gt;&lt;/p&gt;&#xA;" OwnerUserId="543" LastEditorUserId="543" LastEditDate="2024-03-05T15:00:38.450" LastActivityDate="2024-03-05T15:00:38.450" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="26040" PostTypeId="1" CreationDate="2024-03-05T13:48:48.280" Score="1" ViewCount="28" Body="&lt;p&gt;I am looking for a database where I can access 18O data from planktonic foraminifera, but so far, I have only come across the &lt;a href=&quot;https://www.pangaea.de/&quot; rel=&quot;nofollow noreferrer&quot;&gt;PANGAEA&lt;/a&gt; database. Since this site is primarily maintained by German research institutes, are there any international databases or other national databases available?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2024-03-05T13:48:48.280" Title="Which global scientific platforms exist to access ocean science-related data?" Tags="|oceanography|database|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="26041" PostTypeId="2" ParentId="26038" CreationDate="2024-03-05T18:27:11.747" Score="1" Body="&lt;p&gt;Over long periods of time, the slope tends towards having the same net erosion rate everywhere so that the shape remains constant (equilibrium).  For a uniform material that's not excessively steep, that gives you the stereotypical rounded hill, since erosion at lower slopes is roughly proportional to the slope, so the slope has to steadily increase to keep &lt;span class=&quot;math-container&quot;&gt;$erosion_{net}=erosion_{here} - erosion_{above}$&lt;/span&gt; constant (where erosion from above provides new soil here).&lt;/p&gt;&#xA;&lt;p&gt;In the case of a mesa, the harder rock above has a much lower erosion rate than the softer rock below, so a consistent shape is maintained if the lower slopes are much shallower than the upper slopes.  Consider two alternative starting points:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The whole thing is very steep.  Fast erosion of the softer material below quickly levels out the slopes there (stuff falls to the bottom) while undermining the caprock, which leads to slope failure above and a cliff.  You now have a mesa.&lt;/li&gt;&#xA;&lt;li&gt;The whole thing is shallowly-sloped.  Very little erosion happens from the caprock, while the softer material below is eroded more quickly until it undermines the caprock, resulting in slope failure and a cliff.  You now have a mesa.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I'm not too familiar with hoodoos, but it appears that some of the &amp;quot;protection&amp;quot; is because the column is under relatively high compression.  Rock/soil material that's under high compression is more resistant to shear stress.&lt;/p&gt;&#xA;" OwnerUserId="26713" LastActivityDate="2024-03-05T18:27:11.747" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26042" PostTypeId="1" CreationDate="2024-03-06T03:24:19.740" Score="2" ViewCount="48" Body="&lt;p&gt;I have already searched the web for information on the formation of &lt;a href=&quot;https://en.wikipedia.org/wiki/Satellite_tornado&quot; rel=&quot;nofollow noreferrer&quot;&gt;satellite tornadoes&lt;/a&gt; but all the sites say the mechanism is unknown.&lt;/p&gt;&#xA;&lt;p&gt;What are the current leading theories for their formation?&lt;/p&gt;&#xA;" OwnerUserId="30498" LastEditorUserId="30498" LastEditDate="2024-03-10T22:13:37.000" LastActivityDate="2024-03-10T22:13:37.000" Title="What are the current theories on the formation of satellite tornados" Tags="|meteorology|wind|storms|thunderstorm|tornado|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="26044" PostTypeId="1" CreationDate="2024-03-07T14:21:50.453" Score="0" ViewCount="27" Body="&lt;p&gt;I have ERA5 wind data information in GRIB format for the whole earth for September 2017 (all days and hours). This gives me around 912 variables in the list.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FkfHL.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FkfHL.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;I am trying to plot it using the code I found online in jupyterlab. However, it does not show me any plot.&#xA;Also, when I run these codes, the jupyter lab kernel restarts.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;ax1 = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))&#xA;&#xA;ax1.coastlines()&#xA;&#xA;ax1.stock_img()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;Apart from that, I am also trying to extract information the information only for island of Dominica or boundary box extent [N:15.88, W:-62.21, S:14.78, E:-60.68]&#xA;Please tell me how can I modify this code so I can plot the information fo my aoi and also extract the information.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;import pygrib&#xA;import numpy as np&#xA;import matplotlib.pyplot as plt&#xA;import cartopy.crs as ccrs&#xA;from cartopy.mpl.ticker import LongitudeFormatter, LatitudeFormatter&#xA;import sys&#xA;&#xA;file = 'Whole_earth.grib'&#xA;grbs = pygrib.open(file)&#xA;for g in grbs:&#xA;    lats, lons = g.latlons() # lats - latitude, lons - longitude&#xA;    lats, lons = np.array(lats), np.array(lons)&#xA;&#xA;grb_uwind = grbs.select()[0] #U 10m wind component for 2017-09-08 &#xA;grb_vwind = grbs.select()[1] #V 10m wind component for 2017-09-08&#xA;data_uwind = grb_uwind.values #U 10m wind values in m/s&#xA;data_vwind = grb_vwind.values #V 10m wind values in m/s&#xA;&#xA;print(lons.shape)&#xA;print(lats.shape)&#xA;print(data_uwind.shape)&#xA;print(data_vwind.shape)&#xA;&#xA;ax1 = plt.axes(projection=ccrs.PlateCarree(central_longitude=180))&#xA;&#xA;ax1.coastlines()&#xA;&#xA;ax1.stock_img()&#xA;&#xA;ax1.set_xticks([0, 60, 120, 180, 240, 300, 359.99], crs=ccrs.PlateCarree())&#xA;ax1.set_yticks([-90, -60, -30, 0, 30, 60, 90], crs=ccrs.PlateCarree())&#xA;lon_formatter = LongitudeFormatter(zero_direction_label=True,&#xA;                               number_format='.0f')&#xA;lat_formatter = LatitudeFormatter()&#xA;ax1.xaxis.set_major_formatter(lon_formatter)&#xA;ax1.yaxis.set_major_formatter(lat_formatter)&#xA;ax1.barbs(lons[::50,::50],lats[::50,::50],data_uwind[::50,::50],&#xA;  data_vwind[::50,::50],transform=ccrs.PlateCarree())&#xA;&#xA;plt.savefig('esse.png')&#xA;plt.show()&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="31596" LastEditorUserId="31596" LastEditDate="2024-03-07T15:27:07.157" LastActivityDate="2024-03-07T15:27:07.157" Title="Plot and export ERA5 wind data for the whole world: GRIB format" Tags="|wind|python|" AnswerCount="0" CommentCount="3" ClosedDate="2024-03-13T09:50:49.103" ContentLicense="CC BY-SA 4.0" />
  <row Id="26045" PostTypeId="5" CreationDate="2024-03-08T07:18:37.297" Score="0" Body="&lt;p&gt;For questions concerning or related to subjects, locations, and fields focused on the state of California&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-03-19T23:14:12.640" LastActivityDate="2024-03-19T23:14:12.640" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26046" PostTypeId="4" CreationDate="2024-03-08T07:18:37.297" Score="0" Body="For questions concerning or related to subjects, locations, and fields focused on the state of California " OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-03-19T23:14:31.600" LastActivityDate="2024-03-19T23:14:31.600" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26047" PostTypeId="1" CreationDate="2024-03-08T15:31:48.173" Score="3" ViewCount="53" Body="&lt;p&gt;I am talking about the Northern hemisphere, specifically Europe. And it's true in every Europen country I've visited. The sky always seems to be paler in the Northern direction, compared to the Western/Eastern directions. Due South is even paler than the North due to the Sun being there during most the day of course. My question is why are East and West are darker shades when the sun isn't there, for example during midday? When the sun is still in the Eastern sky the West is very dark. When the sun goes to the Western part of the sky the  East looks a darker shade of blue than the West and the North. And I'mn not talking about sunrises and sunsets. At the same time during midday when the Sun is shining in the South, the oppsosite direction (North) isn't as dark as East and West, it's quite a pale shade of blue.&lt;/p&gt;&#xA;&lt;p&gt;Go to any European city during midday. The Southern portion of the sky with the sun will be the brightest hue of blues, it turns to deeper shades quite fast on the Eastern and Western parts of the sky. And when you look at the North the hue starts becomign paler again.&lt;/p&gt;&#xA;&lt;p&gt;This 360 degree photo of Prague shows it best, the Northern potion of the sky is in the right and there's almost like a whitish hallo there, while the deeper blues in the East/West porions (maybe not true East/West) go closer to the Earth:&#xA;&lt;a href=&quot;https://i.stack.imgur.com/C46RS.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/C46RS.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="31599" LastActivityDate="2024-03-14T13:56:51.803" Title="Why is the sky a paler shade of blue in the Northern part of the sky compared to the East and West?" Tags="|astronomy|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26048" PostTypeId="1" CreationDate="2024-03-08T17:37:07.220" Score="-1" ViewCount="54" Body="&lt;p&gt;What did Ptolemy mean when he said that&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Geography is the wonderful science of seeing the glimpse of earth in heaven.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Does it have to do with the differences in celestial bodies when seen from different areas of the earth?&lt;/p&gt;&#xA;" OwnerUserId="31601" LastEditorUserId="31601" LastEditDate="2024-03-08T17:38:39.373" LastActivityDate="2024-03-08T17:38:39.373" Title="What did Ptolemy mean when he" Tags="|geography|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="26049" PostTypeId="1" CreationDate="2024-03-08T22:47:02.413" Score="1" ViewCount="57" Body="&lt;p&gt;The weaker local gravity in the &lt;a href=&quot;https://en.wikipedia.org/wiki/Indian_Ocean_Geoid_Low&quot; rel=&quot;nofollow noreferrer&quot;&gt;Indian Ocean geoid low&lt;/a&gt; (IOGL) causes the sea level to be 106 m below the &lt;a href=&quot;https://en.wikipedia.org/wiki/Global_mean_sea_level&quot; rel=&quot;nofollow noreferrer&quot;&gt;global mean sea level&lt;/a&gt;. Why is that ?&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;&lt;em&gt;&amp;quot;Because of this lower density, the gravitational pull in the IOGL&#xA;region is weaker than normal.&amp;quot;&lt;/em&gt; &lt;a href=&quot;https://en.wikipedia.org/wiki/Indian_Ocean_Geoid_Low&quot; rel=&quot;nofollow noreferrer&quot;&gt;source&lt;/a&gt;&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;I would have expected the exact opposite: namely that &lt;strong&gt;stronger&lt;/strong&gt; (not weaker) gravitational pull would pull the water down &lt;strong&gt;stronger&lt;/strong&gt; and therefore cause a lower sea level. What is wrong with my logic ?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/5rMVo.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/5rMVo.png&quot; alt=&quot;earth gravitational model&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="13784" LastEditorUserId="13784" LastEditDate="2024-03-09T21:28:25.200" LastActivityDate="2024-03-09T21:28:25.200" Title="Why does weaker local gravity cause lower sea level?" Tags="|geophysics|oceanography|sea-level|gravity|ocean-models|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="26050" PostTypeId="1" AcceptedAnswerId="26059" CreationDate="2024-03-09T03:16:54.113" Score="2" ViewCount="78" Body="&lt;p&gt;It seems there are multiple chemical reactions (&lt;a href=&quot;https://chemistry.stackexchange.com/questions/915/how-can-carbon-dioxide-be-converted-into-carbon-and-oxygen&quot;&gt;from this question&lt;/a&gt; and internet in general) where &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; can be converted to &lt;span class=&quot;math-container&quot;&gt;$O_2$&lt;/span&gt;. If this is the case, can someone please explain the challenges (manufacturing, setup costs, raw material scarcity etc) we are facing in reducing &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt; in atmosphere? Also, what are the state-of-the-art techniques used to reduce &lt;span class=&quot;math-container&quot;&gt;$CO_2$&lt;/span&gt;?&lt;/p&gt;&#xA;" OwnerUserId="31602" LastEditorUserId="239" LastEditDate="2024-03-09T23:16:27.700" LastActivityDate="2024-03-27T02:35:18.170" Title="What are the state-of-art techniques in capturing carbon dioxide and/or converting it to oxygen and their challenges?" Tags="|climate-change|carbon-cycle|" AnswerCount="3" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26051" PostTypeId="2" ParentId="26050" CreationDate="2024-03-09T23:34:47.347" Score="0" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;Also, what are the state-of-the-art techniques used to reduce &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt;?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;That the easy part of the question to answer: Drastically reduce human use of fossil fuels, thereby drastically reducing the amount of fossil fuel based &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; into the atmosphere. Humanity is partway on the path toward achieving that. Multiple solutions do exist.&lt;/p&gt;&#xA;&lt;p&gt;As for the rest of the question, there are no other viable solutions. Most proposed alternatives don't scale up well, most are ridiculously expensive, many have lots of nasty side effects, and many turn out to be not carbon neutral due to energy consumption (assuming energy production remains fossil fuel based).&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2024-03-09T23:34:47.347" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="26052" PostTypeId="1" CreationDate="2024-03-10T09:29:40.720" Score="1" ViewCount="23" Body="&lt;p&gt;In the book by &lt;em&gt;S. Pal Arya &amp;quot;Introduction to Micrometeorology&amp;quot;&lt;/em&gt; there is a chapter about Laminar Ekman Layers.&#xA;I refer to the following example:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/CDWri.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/CDWri.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Variables are:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;U, V wind velocity in x, y direction&lt;/li&gt;&#xA;&lt;li&gt;G Geostrophic wind magnitude&lt;/li&gt;&#xA;&lt;li&gt;Ug, Vg geostrophic wind in x, y&lt;/li&gt;&#xA;&lt;li&gt;f Coriolis Parameter&lt;/li&gt;&#xA;&lt;li&gt;&lt;span class=&quot;math-container&quot;&gt;$h_s$&lt;/span&gt; a reference height at which Us is given (Vs is zero)&lt;/li&gt;&#xA;&lt;li&gt;K effective viscosity&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;The boundary condition is in particular:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/rDjaU.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/rDjaU.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;In a subsequent consideration, they state, that at &lt;span class=&quot;math-container&quot;&gt;$z=h_s$&lt;/span&gt; we need to have the following:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/FPCqd.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/FPCqd.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Why this is the case? Why must shear stress be parallel to the wind? I understand the mathematical condition derived from the statement, but why must stress in y-direction be zero? There could be a shear of v along z and this would give rise to non vanishing &lt;span class=&quot;math-container&quot;&gt;$\tau_{zy}$&lt;/span&gt;, even when &lt;span class=&quot;math-container&quot;&gt;$v(z)=0$&lt;/span&gt; - so in general this is not the case!&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2024-03-11T13:29:37.240" LastActivityDate="2024-03-11T13:29:37.240" Title="Why shear stress vector must be parallel to flow in this example?" Tags="|atmosphere-modelling|fluid-dynamics|planetary-boundary-layer|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26053" PostTypeId="2" ParentId="17995" CreationDate="2024-03-10T10:04:30.310" Score="1" Body="&lt;p&gt;It depends on which latitude you are in. In polar regions, a relatively linear equation can be used. This is because the so-called Liatiude effect has an extreme influence on the 18O signature.&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$\delta^{18}\textrm{O} = (0.521 \pm 0.014)t_a - (14.96 \pm 0.21)^0\!\!/\!_{00}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;For further information: &lt;a href=&quot;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/isotopic-fractionation&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.sciencedirect.com/topics/earth-and-planetary-sciences/isotopic-fractionation&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;However, in latitudes such as those of Europe, there are additional effects that strongly influence the isotopic signature. For example, the intensity of precipitation is responsible for causing the 18O signature to become more negative with increasing rainfall. As far as I know, a paper on this topic will hopefully be published soon, and I will then provide the link.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2024-03-10T10:04:30.310" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26055" PostTypeId="1" CreationDate="2024-03-10T18:06:46.170" Score="1" ViewCount="30" Body="&lt;p&gt;(For context, this is for a science fiction novel in which a chunk of an earth-like planet is expelled. I suppose the nearest real-world situation would be a large meteorite strike.)&lt;/p&gt;&#xA;&lt;p&gt;Suppose an impact, explosion, or other &amp;quot;large&amp;quot; event strips away the lithosphere over a reasonably large chunk of the Earth's surface. For about how long would the area remain highly volcanic?&lt;/p&gt;&#xA;&lt;p&gt;To explore this, I wrote a crude numerical simulation of radiation into space (using the Stefan-Boltzmann law, assuming no atmospheric blanket) and conduction in the mantle (using Newton's Law of Cooling, assuming no convection).&lt;/p&gt;&#xA;&lt;p&gt;If you're curious, the code is &lt;a href=&quot;https://pastebin.com/V01fZR2h&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. It produces somewhat sane results.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/bf0B6.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/bf0B6.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;This shows temperature (Kelvin) at various depths (metres) over a few decades. The surface cools to boiling after a few years, and we have 20 metres of solid rock after about 20 years.&lt;/p&gt;&#xA;&lt;p&gt;That much seems intuitively reasonable, but it doesn't answer my question. Perhaps this model in combination with some other information would get me there.&lt;/p&gt;&#xA;&lt;p&gt;For example, if we could say &amp;quot;we need about 100m of solidified surface rock at &amp;lt;1000K to prevent volcanic activity generally, but we would still expect specific points of intense volcanic activity for at least a hundred years after that&amp;quot;, that would answer the question for my purposes.&lt;/p&gt;&#xA;&lt;p&gt;What geological conditions would need to occur after such a cataclysm for the surface to stabilise? Say, to the point that a human with breathing apparatus could walk around on it, or that it would look fairly boring from space?&lt;/p&gt;&#xA;" OwnerUserId="770" LastActivityDate="2024-03-10T18:06:46.170" Title="How long would it take for a large impact crater to stop being volcanic?" Tags="|volcanology|mantle|meteorite|lithosphere|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="26056" PostTypeId="1" CreationDate="2024-03-11T02:24:28.850" Score="0" ViewCount="83" Body="&lt;p&gt;The only things I could find on the internet were that they had vortices and are marked by an isolated cloud, for example, in the American Met. Soc. glossary: &lt;a href=&quot;https://glossary.ametsoc.org/wiki/Bull%27s_eye_squall&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://glossary.ametsoc.org/wiki/Bull%27s_eye_squall&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;How do bulls eye squalls occur?&lt;/p&gt;&#xA;" OwnerUserId="30498" LastEditorUserId="106" LastEditDate="2024-03-14T13:29:58.380" LastActivityDate="2024-03-14T13:29:58.380" Title="How do bull’s eye squalls occur?" Tags="|atmosphere|wind|clouds|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="26057" PostTypeId="1" CreationDate="2024-03-11T07:08:25.340" Score="0" ViewCount="11" Body="&lt;p&gt;When the Zanclean flood filled the Mediterranean after the Messinian Salinity Crisis then sea levels around the world would have dropped leaving many stranded reefs and beaches.&lt;/p&gt;&#xA;&lt;p&gt;Are there any instances of these stranded reefs and beaches around the world?&lt;/p&gt;&#xA;&lt;p&gt;Also the sudden drop in sea level would have left reef building communities high and dry with no means to reproduce except any larvae that happened to be floating in the sea at the time of the flood. Is there any sign of a sudden catastrophe in reef building ecosystems?&lt;/p&gt;&#xA;" OwnerUserId="14354" LastActivityDate="2024-03-11T07:08:25.340" Title="Stranded reefs after the Zanclean flood?" Tags="|zanclean|reefs|messinian|stranded|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26059" PostTypeId="2" ParentId="26050" CreationDate="2024-03-11T12:15:17.480" Score="1" Body="&lt;p&gt;Carbon capture and storage (CCS) and direct air capture (DAC) are massively energy intensive processes. So a large barrier to deployment is finding the energy to run the capture plants.&lt;/p&gt;&#xA;&lt;p&gt;Since we emit so much CO2 from our power generation it's better to just turn off that power generation than use any of the resulting energy to then partly undo the process done in the power station. So in a world with any energy generation from fossil fuels, it basically makes no sense to use energy on capturing carbon, we should just turn off that energy generation.&lt;/p&gt;&#xA;&lt;p&gt;There are some tiny carbon capture plants operating in Iceland since they have an abundance of geothermal energy.&lt;/p&gt;&#xA;&lt;p&gt;After/if we transition to renewable energy it will still take energy/resources to build renewable energy infrastructure. Energy doesn't suddenly magically become free. So the massive energy bill of trying to capture carbon is still going to be a problem. As ever, the best solution is to stop emitting carbon dioxide. Carbon capture is pushed hard by oil companies for several reasons, and one of those is that it justifies them continuing to profit off destroying the atmosphere for decades more while they watch their delaying tactics play out.&lt;/p&gt;&#xA;" OwnerUserId="27942" LastActivityDate="2024-03-11T12:15:17.480" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26062" PostTypeId="2" ParentId="12712" CreationDate="2024-03-12T02:50:40.937" Score="5" Body="&lt;p&gt;Six plus years after the fact, I find the accepted answer to be a bit insufficient. With that,&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;but what specifically caused the CO2 to fluctuate?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;Notice in the two graphs how the temperature drop and carbon dioxide drop gradually at the onset of a glaciation while the temperature rise and carbon dioxide rise at the end of a glaciation are comparatively sharp.&lt;/p&gt;&#xA;&lt;p&gt;The onset of a glaciation was triggered by summertime temperatures in the far north being mild, mild enough for snow from the previous winter to last through the summer. A very widely used metric is whether the mean temperature over land at 65° north latitude was under 0° Celsius (32° Fahrenheit). Several things occur once snow can last over the summer:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The Earth's albedo increases due to the snow (and later, ice) coverage.&lt;/li&gt;&#xA;&lt;li&gt;The oceans cool, thereby increasing the oceans ability to dissolve carbon dioxide as &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; dissolves much more readily in cold water as opposed to warm water.&lt;/li&gt;&#xA;&lt;li&gt;Just as the Antarctic ice has trapped &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt;, so does the snow / firn / ice that is beginning to cover the far north.&lt;/li&gt;&#xA;&lt;li&gt;The reduced &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; levels in the atmosphere result in even more cooling.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;While this is a vicious loop, it nonetheless is a gradual process. This is why the onset of a glaciation is slow. Compare this with the end of a glaciation, which is very quick in comparison. Once conditions are ripe for warming&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The melting glacial ice releases the &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; that it had trapped. At high enough pressures and low enough temperatures, the &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; embedded in the snow (and then firn, and then ice) forms clathrates. Clathrates are unstable not-quite molecules.&lt;/li&gt;&#xA;&lt;li&gt;The warming temperatures cause the ocean temperatures to rise. Because &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; is less soluble in warm water than in cold water, the atmospheric &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; that had been absorbed by the oceans is released back to the atmosphere.&lt;/li&gt;&#xA;&lt;li&gt;The increased &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; levels in the atmosphere cause the Earth to warm even more.&lt;/li&gt;&#xA;&lt;li&gt;The melting ice exposes bare rock, which has a very low albedo (about 10%), compared with snow and ice (about 90%).&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Like the onset of a glaciation, the end of a glaciation is also a vicious cycle. The vicious cycle at the end of a glaciation tends to be very vicious indeed as the melting glacial ice and warming oceans release their bottled-up &lt;span class=&quot;math-container&quot;&gt;$\text{CO}_2$&lt;/span&gt; quickly once the process starts.&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;I assume that Milankovich Cycles are what caused the variations observed in temperature in the ice record&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;That is true, to some extent. One of the biggest mysteries with regard to paleoclimate is why the Earth switched from a 41000 year glaciation cycle to a 100000 year cycle. This happened about a million years ago. The problem is that while there is a roughly 100000 year cycle in one of the drivers of the Milankovich cycles, it supposedly is a very weak driver. The ~41000 year drivers are much stronger. While the onset of a glaciation is highly consistent Milankovich cycle theory (the conditions have to be ripe for temperatures at 65° latitude to remain below freezing all summer long), the end of a glaciation for the last million years is not. Why did ice sheets start persisting for ~100000 years?&lt;/p&gt;&#xA;&lt;p&gt;This 100000 year problem remains a bit of a mystery, but one explanation I particularly like is that the ~41000 glaciations eventually scraped the regolith in the far north out to sea. The scraped clean rock gave the ice a nice solid surface to cling on to and thereby persist over what would have been the end of a weak ~41000 glaciation cycle. (Those older ~41000 glaciation cycles were weaker than are the current ~100000 year cycles.) The weaker ~100000 year signal eventually came to dominate due to hysteresis effects.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2024-03-12T02:50:40.937" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="26063" PostTypeId="2" ParentId="26056" CreationDate="2024-03-12T08:11:38.290" Score="0" Body="&lt;p&gt;This weather phenomenon occurs when, due to ascending winds above a typically invisible storm or vortex, there is a significant acceleration (for at least 1 minute). Hence the term &amp;quot;squall,&amp;quot; which describes the increase in wind speed.&#xA;However during storms, Bulls Eye is the term used when it causes significant damage to property (similar to hitting the bull's eye in archery). Besides these fast winds, there are also Bulls Eye storms, etc.&lt;/p&gt;&#xA;&lt;p&gt;This phenomenon often occurs in countries where high air temperatures can be generated, such as Argentina, Chile, etc.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="26841" LastEditDate="2024-03-12T13:58:24.247" LastActivityDate="2024-03-12T13:58:24.247" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="26065" PostTypeId="1" CreationDate="2024-03-13T08:08:34.587" Score="3" ViewCount="81" Body="&lt;p&gt;UPDATE: I believe I have found the mistake. I had missed that the project instructions stated that conductance of sensible heat flux should be equal to aerodynamic conductance. The model behaves as expected now that I've made that adjustment. Thank you to everyone who chimed in!&lt;/p&gt;&#xA;&lt;p&gt;Original question:&lt;/p&gt;&#xA;&lt;p&gt;I am trying to model Penman-Monteith reference evapotranspiration in MATLAB using Ameriflux data (&lt;a href=&quot;https://ameriflux.lbl.gov/sites/siteinfo/US-Ro4&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://ameriflux.lbl.gov/sites/siteinfo/US-Ro4&lt;/a&gt;, data from June 17, 2021). The task is to calibrate the model to the evapotranspiration data (the latter calculated using latent heat flux) by adjusting the value for canopy conductance. The canopy conductance was expected to lie somewhere between 0.002 and 0.03 m/s. I was asked to plot an overestimate, an underestimate, and a best fit model on the same plot as the ET data.&lt;/p&gt;&#xA;&lt;p&gt;Unfortunately, it seems that the model is off. Regardless of the choice of G_c, the plot oscillates in unexpected places, and contains negative values. Also, the G_c value that minimizes error--as far as I've found with the current approach of manual adjustment--lies outside the recommended range.&lt;/p&gt;&#xA;&lt;p&gt;I will owe a life debt to anyone who can point me toward my mistake(s). Apologies for the needlessly bothersome aspects of the code, the large images, and any breaches I may have made of forum etiquette: I'm a newbie to both MATLAB and StackExchange.&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;clear&#xA;load Project2_AmerifluxData_2021.mat&#xA;dates = datevec(FluxData.TIMESTAMP_START);&#xA;selector = dates(:, 1) == 2021 &amp;amp; dates(:, 2) == 6 &amp;amp; dates(:, 3) == 17;&#xA;Flux_6_17_21 = FluxData(selector, :);&#xA;&#xA;% Calculate evapotranspiration from LE data&#xA;Lv = 2257000; % Latent heat of vaporization [J/kg]&#xA;E = Flux_6_17_21.LE/Lv; % Evapotranspiration rate from LE data [kg/(s·m^2)]&#xA;&#xA;% Account for other terms in the Penman-Monteith equation&#xA;&#xA;% Temperature&#xA;TA_K = Flux_6_17_21.TA + 273.15; % Air temperature [K] at measurement height z&#xA;TS_all = [Flux_6_17_21.TS_1_1_1, Flux_6_17_21.TS_1_2_1, Flux_6_17_21.TS_1_3_1, Flux_6_17_21.TS_1_4_1];&#xA;TS_C = mean(TS_all, 2); % Mean of different sensors' surface temperature readings [deg C]&#xA;TS_K = TS_C + 273.15; % Mean surface temperature [K]&#xA;&#xA;% Vapor pressure&#xA;PA = 1000 * Flux_6_17_21.PA; % Atmospheric pressure [Pa]&#xA;a = 611; % Clausius-Clapeyron fitting parameter [Pa]&#xA;b = 17.27; % C-C parameter [-]&#xA;c = 237.3; % C-C parameter [deg C]&#xA;e_ss = a * exp(b * TS_C ./ (TS_C + c)); % Saturated water vapor &#xA;% pressure [Pa] at surface, from Clausius-Clapeyron&#xA;e_sz = a * exp(b * Flux_6_17_21.TA ./ (Flux_6_17_21.TA + c)); % Sat &#xA;% water vapor pressure [Pa] at z&#xA;e_az = e_sz .* Flux_6_17_21.RH ./ 100; % Actual water vapor pressure [Pa] at z&#xA;D = Flux_6_17_21.VPD_PI .* 100; % Vapor pressure deficit [Pa]&#xA;&#xA;% Delta [Pa/K]&#xA;delt = a * b * c ./ (Flux_6_17_21.TA + c).^2 .* exp(b * Flux_6_17_21.TA ./ (Flux_6_17_21.TA + c));&#xA;% Slope of C-C eqn&#xA;&#xA;% Air density&#xA;R = 8.314; % Universal gas constant [J/(K·mol)]&#xA;c_pd = 1005; % Specific heat capacity of dry air [J/(kg·K)]&#xA;c_pw = 1930; % Specific heat capacity of water vapor [J/(kg·K)]&#xA;mol_fract = e_az ./ PA; % Mol fraction [-] of water vapor at z&#xA;c_p = (1-mol_fract) .* c_pd + mol_fract .* c_pw; % Specific heat capacity &#xA;% of moist air [J/(kg·K)]&#xA;p_d = PA - e_az; % Partial pressure of dry air [Pa] at z&#xA;M_a = 0.02897; % Molar mass of dry air [kg/mol]&#xA;M_w = 0.018; % Molar mass of water [kg/mol]&#xA;rho_a = (M_w * e_az + M_a * p_d) ./ (R * TA_K); % Mass density of air [kg/m^3]&#xA;&#xA;% Aerodynamic conductance&#xA;kappa = 0.41; % von Karman constant [-]&#xA;z = 10; % Measurement height [m]&#xA;h = 0.5; % Height of vegetation canopy [m]&#xA;d = 0.667 * h; % Zero plane displacement [m]&#xA;zm = 0.123 * h; % Roughness length for momentum transfer [m]&#xA;zh = 0.1 * zm; % Roughness length for heat &amp;amp; water vapor [m]&#xA;G_a = kappa^2 * Flux_6_17_21.WS ./ (log((z - d)/zm) * log((z - d)/zh)); % Aerodynamic &#xA;% conductance [m/s]&#xA;&#xA;% Other conductances (all [m/s])&#xA;G_c = 0.12; % Canopy conductance, used interchangeably with surface conductance. Vary this to find best fit&#xA;G_L = G_c .* G_a ./ (G_c + G_a); % Total conductance of latent heat flux&#xA;G_H = Flux_6_17_21.H ./ (rho_a .* c_p .* (TS_K - TA_K)); % Conductance of sensible heat flux&#xA;&#xA;% Psychrometric constant [Pa·K]&#xA;gamma = c_p .* PA / (Lv * M_w / M_a);&#xA;&#xA;% Recalculate ET with Penman-Monteith equation&#xA;E_PM = (delt .* (Flux_6_17_21.NETRAD - Flux_6_17_21.G) + rho_a .* c_p .* G_H .* D) ./ (Lv ...&#xA;    * (delt + gamma .* G_H ./ G_L)); % [kg/(s·m^2)]&#xA;&#xA;Error = mean(rmse(E, E_PM, 2)) % Look for value of G_c that minimizes error between E and E_PM&#xA;&#xA;% Variation #1&#xA;G_c_1 = 0.03; % [m/s]&#xA;G_L_ov = G_c_1 .* G_a ./ (G_c_1 + G_a); % [m/s]&#xA;E_PM_ov = (delt .* (Flux_6_17_21.NETRAD - Flux_6_17_21.G) + rho_a .* c_p .* G_H .* D) ./ (Lv ...&#xA;    * (delt + gamma .* G_H ./ G_L_ov)); % [kg/(s·m^2)]&#xA;&#xA;% Variation #2&#xA;G_c_2 = 0.002; % [m/s]&#xA;G_L_und = G_c_2 .* G_a ./ (G_c_2 + G_a); % [m/s]&#xA;E_PM_und = (delt .* (Flux_6_17_21.NETRAD - Flux_6_17_21.G) + rho_a .* c_p .* G_H .* D) ./ (Lv ...&#xA;    * (delt + gamma .* G_H ./ G_L_und)); % [kg/(s·m^2)]&#xA;&#xA;figure(1)&#xA;plot (Flux_6_17_21.TIMESTAMP_START, E, '-b')&#xA;hold on&#xA;plot (Flux_6_17_21.TIMESTAMP_START, E_PM, '--g')&#xA;plot (Flux_6_17_21.TIMESTAMP_START, E_PM_ov, '-.k')&#xA;plot (Flux_6_17_21.TIMESTAMP_START, E_PM_und, ':r')&#xA;datetick('x', 'HHPM')&#xA;xlabel('Hour')&#xA;ylabel('Evapotranspiration rate [kg/(s·m^{2})]')&#xA;legend ('Data', ['Penman-Monteith equation with G_c = ', num2str(G_c), ...&#xA;    ' m/s'], ['Penman-Monteith equation with G_c = ', num2str(G_c_1), ...&#xA;    ' m/s'], ['Penman-Monteith equation with G_c = ', num2str(G_c_2), ' m/s'])&#xA;legend('Location', 'northoutside')&#xA;hold off&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/9a4bC.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/9a4bC.png&quot; alt=&quot;Table of data variable descriptions&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/jaeNm.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/jaeNm.png&quot; alt=&quot;Data variables in MATLAB&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/1AQzr.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/1AQzr.png&quot; alt=&quot;More data variables in MATLAB&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/XXNrt.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XXNrt.png&quot; alt=&quot;Graph example 1&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/a7yga.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/a7yga.png&quot; alt=&quot;Graph example 2&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/fnp6k.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fnp6k.png&quot; alt=&quot;Graph example 3&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="31625" LastEditorUserId="31625" LastEditDate="2024-03-17T00:14:38.283" LastActivityDate="2024-03-17T00:14:38.283" Title="What's wrong with my Penman-Monteith model?" Tags="|hydrology|models|evaporation|matlab|" AnswerCount="0" CommentCount="11" ContentLicense="CC BY-SA 4.0" />
  <row Id="26066" PostTypeId="1" CreationDate="2024-03-13T16:32:16.157" Score="1" ViewCount="21" Body="&lt;p&gt;I want to calculate &amp;quot;feels like&amp;quot; temperature indoors, with no sunlight or wind. But I don't know which method to use or if I should combine methods. Below I've given some research results I obtained but the correct method can be something else.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;&lt;p&gt;&lt;a href=&quot;https://www.wpc.ncep.noaa.gov/html/heatindex_equation.shtml&quot; rel=&quot;nofollow noreferrer&quot;&gt;Heat Index Calculation&lt;/a&gt; looks promising but I know it is mostly used for high temperatures. At least there are adjustments for low temperatures as well.&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;li&gt;&lt;p&gt;There is also &amp;quot;apparent temperature&amp;quot; calculation given as:&lt;/p&gt;&#xA;&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;AT = Ta + .348&lt;em&gt;e - .70&lt;/em&gt;ws + .70*(Q/ws + 10) - 4.25&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;Where AT is the apparent temperature (C)&lt;/li&gt;&#xA;&lt;li&gt;Ta is the dry bulb temperature (C)&lt;/li&gt;&#xA;&lt;li&gt;e is the humidity (hPa)&lt;/li&gt;&#xA;&lt;li&gt;ws is the wind speed (m/s)&lt;/li&gt;&#xA;&lt;li&gt;Q is the net radiation absorbed per unit of body surface area&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;I can substitude zero for ws but even then I don't know Q value thus I am not sure if I can use this.&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;There is WetBulb Globe Temperature (WBGT) but it is for outdoor (i guess) because it involves sunlight.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;" OwnerUserId="31626" LastEditorUserId="18088" LastEditDate="2024-03-18T17:39:55.020" LastActivityDate="2024-03-18T17:39:55.020" Title="How to Calculate Indoors Feels Like Temperature for All Seasons?" Tags="|temperature|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="26067" PostTypeId="1" CreationDate="2024-03-14T03:47:15.457" Score="2" ViewCount="66" Body="&lt;p&gt;I was reading the Press Release of World Meteorological Organization press release that was dated March 5, 2024 and I was curious on what they meant by the sentence &amp;quot;The 2023-24 El Niño season has peaked as one of the five strongest on record&amp;quot;. What do they mean by that? Did they mean that since 1900 when they recorded El Nino, the 2023-24 El Niño season was the fifth strongest on record recorded by World Meteorological Organization?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/euQKJ.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/euQKJ.png&quot; alt=&quot;ElNino&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The article that I'm referring to is:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://wmo.int/news/media-centre/el-nino-weakens-impacts-continue&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://wmo.int/news/media-centre/el-nino-weakens-impacts-continue&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Any clarifications will be appreciated. Thank you all!&lt;/p&gt;&#xA;" OwnerUserId="31628" LastEditorUserId="31628" LastEditDate="2024-03-14T03:47:47.390" LastActivityDate="2024-03-22T14:17:03.660" Title="2023-2024 El Nino Season 5th Strongest on Record Meaning" Tags="|meteorology|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="26068" PostTypeId="5" CreationDate="2024-03-14T07:38:50.500" Score="0" Body="&lt;p&gt;Phase transition of water vapor from gas to liquid&lt;/p&gt;&#xA;" OwnerUserId="-1" LastEditorUserId="6298" LastEditDate="2024-03-14T08:37:01.883" LastActivityDate="2024-03-14T08:37:01.883" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26069" PostTypeId="4" CreationDate="2024-03-14T07:38:50.500" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2024-03-14T07:38:50.500" LastActivityDate="2024-03-14T07:38:50.500" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26070" PostTypeId="2" ParentId="26047" CreationDate="2024-03-14T11:59:42.737" Score="0" Body="&lt;p&gt;if I understand well your question there are two cases:&#xA;a) midday: in Prague, Berlin etc the sun is in the south and the angle is the smallest one. (see the attachment)&lt;a href=&quot;https://i.stack.imgur.com/BhJJj.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/BhJJj.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;In this case, the light of the sun has to cover less distance to reach the Earth. In other words, less scattering. Thus, it is more common for the light to go straight without scattering as direct flux.&lt;/p&gt;&#xA;&lt;p&gt;b) other phases of the day. Thus, the angle is higher. The distance the light has to cover increases with the cosine. In this case, the light has to cover more distance and is more likely to be randomly scattered as it is scattered by the atoms in the atmosphere.&lt;/p&gt;&#xA;&lt;p&gt;When the atmosphere is polluted, larger particles = Mie, there is no preference according to wavelength, so in very polluted atmosphere the sun more difficult to be seen.&lt;/p&gt;&#xA;&lt;p&gt;Note that there are two kinds of scattering Mie and Rayleigh. Rayleigh scattering applies more for violet and blue and is the reason for the blue color of the sky.&lt;/p&gt;&#xA;&lt;p&gt;But in other case further study of Rayleigh and Mie scattering will help you more (than me) to understand this phenomenon.&#xA;Hope that helps&lt;/p&gt;&#xA;" OwnerUserId="30273" LastEditorUserId="30273" LastEditDate="2024-03-14T13:56:51.803" LastActivityDate="2024-03-14T13:56:51.803" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26071" PostTypeId="2" ParentId="24705" CreationDate="2024-03-14T14:35:25.697" Score="2" Body="&lt;p&gt;The scale refers to the significant wave height H1/3, which is defined as the mean height of the higher third of all waves occurring in a sea area at a given time.&lt;/p&gt;&#xA;&lt;p&gt;Further reading (but in german):&#xA;&lt;a href=&quot;https://www.dwd.de/DE/service/lexikon/begriffe/S/Signifikante_Wellenhoehe.html?view=renderHelp&amp;amp;nn=17570&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.dwd.de/DE/service/lexikon/begriffe/S/Signifikante_Wellenhoehe.html?view=renderHelp&amp;amp;nn=17570&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/8uV3I.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/8uV3I.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;Fig. &lt;a href=&quot;https://www.scribd.com/doc/208117763/Beaufort-Scale-of-Wind-Force-and-Its-Probable-Wave-Height&quot; rel=&quot;nofollow noreferrer&quot;&gt;Source&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2024-03-14T14:35:25.697" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26072" PostTypeId="1" CreationDate="2024-03-14T22:17:41.083" Score="0" ViewCount="22" Body="&lt;p&gt;We just had a very low low tide in the UK, an equinoctial tide on the 12th of March that was calculated as -0.13m above chart datum, i.e 13cm below the 'Lowest Astronomical Tide'.&lt;/p&gt;&#xA;&lt;p&gt;Check here for tidal heights- &lt;a href=&quot;https://ntslf.org/tides/hilo&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://ntslf.org/tides/hilo&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;How can a tide be lower than the 'Lowest Astronomical Tide' on a chart?&lt;/p&gt;&#xA;" OwnerUserId="31631" LastActivityDate="2024-03-14T22:17:41.083" Title="How can a tidal height be lower than 'Chart Datum'/'LAT' e.g 'Lowest Astronomical Tide'?" Tags="|sea-level|mapping|tides|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="26075" PostTypeId="1" CreationDate="2024-03-15T08:31:25.563" Score="2" ViewCount="64" Body="&lt;p&gt;I want to define different study areas and want to do this here, for example, using the Nordic Seas.&lt;/p&gt;&#xA;&lt;p&gt;According to the definition, this area lies north of Iceland and south of Svalbard.&lt;/p&gt;&#xA;&lt;p&gt;However, are there precise coordinates somewhere that are based on a standardised system (preferably scientifically recognised)?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastEditorUserId="6467" LastEditDate="2024-03-15T12:28:10.580" LastActivityDate="2024-03-19T11:06:01.667" Title="How to define sea areas" Tags="|oceanography|mapping|coordinate-system|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="26076" PostTypeId="2" ParentId="25687" CreationDate="2024-03-15T17:51:27.683" Score="2" Body="&lt;p&gt;Thomas' reasoning is approximately correct but relies on the assumption that the density of water is equal to 1000 &lt;span class=&quot;math-container&quot;&gt;$\frac{kg}{m^3}$&lt;/span&gt;. Since the density of water changes slightly with temperature the above reasoning will fail (slightly) over different temperatures. While these temperature variations are often ignored I think it is still less confusing to express this mathematically. So, if we ignore the time units for now and answer your last question of how to get the depth of water in &lt;span class=&quot;math-container&quot;&gt;$mm$&lt;/span&gt; from &lt;span class=&quot;math-container&quot;&gt;$\frac{kg}{m^2}$&lt;/span&gt;:&lt;/p&gt;&#xA;&lt;p&gt;Given the density of water is ~ 1000 &lt;span class=&quot;math-container&quot;&gt;$\frac{kg}{m^3}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Then the equivilent depth of water in metres is:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$[m] = \frac{\frac{kg}{m^2}}{1000\frac{kg}{m^3}}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;And so the depth of water in mm is:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$[mm] = [m]*1000[\frac{mm}{m}]$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Back to where we started! Thus we've shown &lt;span class=&quot;math-container&quot;&gt;$\frac{kg}{m^2}$&lt;/span&gt; = &lt;span class=&quot;math-container&quot;&gt;$mm$&lt;/span&gt; only if the density of water is ~ 1000 &lt;span class=&quot;math-container&quot;&gt;$\frac{kg}{m^3}$&lt;/span&gt;.&lt;/p&gt;&#xA;&lt;p&gt;Now if we bring back in the seconds we can do:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$[\frac{m}{s}] = \frac{\frac{kg}{m^2s}}{1000\frac{kg}{m^3}}$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$[\frac{mm}{s}] = [\frac{m}{s}]*1000[\frac{mm}{m}]$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;And since there are 3600 seconds in an hour:&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$[\frac{mm}{hr}] = [\frac{m}{s}]*3600[\frac{s}{hr}]$&lt;/span&gt;&lt;/p&gt;&#xA;&lt;p&gt;Slightly over complicated but hopefully helps understand the reasoning...&lt;/p&gt;&#xA;" OwnerUserId="31636" LastEditorUserId="31636" LastEditDate="2024-03-15T19:53:27.863" LastActivityDate="2024-03-15T19:53:27.863" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26077" PostTypeId="1" AcceptedAnswerId="26079" CreationDate="2024-03-15T18:40:42.840" Score="3" ViewCount="39" Body="&lt;p&gt;I am looking at &lt;a href=&quot;https://courses.seas.harvard.edu/climate/eli/Courses/EPS281r/Sources/Thermohaline-circulation/2-THC-Stommel-model-notes.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;Stommel's Two-Box model of ocean circulation&lt;/a&gt;.&lt;/p&gt;&#xA;&lt;p&gt;I get that deep water formation occurs in the polar regions due to cooling of the water and sinking to the bottom. However, just looking at the box model, it looks like the equatorial regions should actually be more dense since salinity has a stronger effect on the density of the water?&lt;/p&gt;&#xA;&lt;p&gt;I am trying to come up with an intuitive explanation of the two-box model, but it isn't making sense with salinity (only temperature). I want a way to explain this concept to anyone, but, right now, explaining the impact of salinity in polar vs equatorial regions is throwing me off.&lt;/p&gt;&#xA;&lt;p&gt;Thanks!&lt;/p&gt;&#xA;" OwnerUserId="30438" LastActivityDate="2024-03-16T21:25:09.053" Title="If salinity affects density more than temperature, why is there a surface current in the N. Atlantic by equatorial regions where the water is saltier?" Tags="|climate-models|ocean-currents|" AnswerCount="1" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26078" PostTypeId="1" CreationDate="2024-03-15T22:06:22.113" Score="1" ViewCount="55" Body="&lt;p&gt;Based on my intuition, I would expect a dust devil to rapidly entrain slow-moving air and stop spinning.&lt;/p&gt;&#xA;&lt;p&gt;My logic goes something like this:&lt;/p&gt;&#xA;&lt;ul&gt;&#xA;&lt;li&gt;The dust devil is made of air that is warmer than the surroundings.&lt;/li&gt;&#xA;&lt;li&gt;Therefore the base of the dust devil will have lower pressure.&lt;/li&gt;&#xA;&lt;li&gt;Friction with the ground prevents gradient wind balance.&lt;/li&gt;&#xA;&lt;li&gt;So environmental air is sucked in and mixes with the air in the dust  devil, slowing down the dust devil’s rotation.&lt;/li&gt;&#xA;&lt;/ul&gt;&#xA;&lt;p&gt;Why doesn't this happen?  &lt;a href=&quot;https://www.weather.gov/fgz/DustDevil#:%7E:text=In%20most%20locations%2C%20dust%20devils,reach%2060%20mph%20or%20greater.&quot; rel=&quot;nofollow noreferrer&quot;&gt;Dust devils typically last minutes, but can even last hours at times.&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="30498" LastEditorUserId="6298" LastEditDate="2024-03-16T00:39:35.180" LastActivityDate="2024-03-16T00:39:35.180" Title="Why aren't dust devils extremely unstable?" Tags="|wind|tornado|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="26079" PostTypeId="2" ParentId="26077" CreationDate="2024-03-16T21:25:09.053" Score="2" Body="&lt;p&gt;In practice in the ocean, density is &lt;a href=&quot;https://www.sciencedirect.com/science/article/abs/pii/B9780750645522100034&quot; rel=&quot;nofollow noreferrer&quot;&gt;dominated by temperature, not salinity&lt;/a&gt; because the range of salinity is relatively small compared to the range of temperature.&lt;/p&gt;&#xA;&lt;p&gt;That wouldn't apply with the addition of fresh water or similar; as far as I can interpret those notes, it looks like that's why a large fresh water flux would shut down the circulation (density gradient large enough to outweigh temperature gradient).&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;The sea surface thermal forcing, which acts in the direction of the present thermohaline circulation in the North Atlantic, is opposite to the haline forcing from the freshwater flux. [From &lt;a href=&quot;https://journals.ametsoc.org/view/journals/phoc/29/12/1520-0485_1999_029_3101_tsotci_2.0.co_2.xml&quot; rel=&quot;nofollow noreferrer&quot;&gt;this&lt;/a&gt; Introduction section.]&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;" OwnerUserId="26713" LastActivityDate="2024-03-16T21:25:09.053" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26080" PostTypeId="1" CreationDate="2024-03-17T00:43:10.593" Score="2" ViewCount="49" Body="&lt;p&gt;This is a set of differential equations originally produced by Stommel (1961) has been simplified in this source (&lt;a href=&quot;https://serc.carleton.edu/integrate/teaching_materials/earth_modeling/student_materials/unit8_article1.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://serc.carleton.edu/integrate/teaching_materials/earth_modeling/student_materials/unit8_article1.html&lt;/a&gt;)&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/H55q8.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/H55q8.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The values of these parameters were picked (somewhat) arbitrarily. So, I am instead trying to think of an intuitive way to understand this through temperature first (without taking into account salinity). It makes sense that, in an absence of water flow, the system would tend toward the equilibrium temperature difference (ΔT_{equilibrium} - ΔT). When there &lt;em&gt;is&lt;/em&gt; ocean flow, I am curious about describing this in an intuitive sense. Does it make sense (with just focusing on the temperature first) that the rate of circulation/ocean flow is directly proportional to these temperature differences (if we ignore salinity first)? How could this be adapted from these ODEs? Is this okay as a conceptual model? Are there too many things behing left unaccounted for even though this is meant to be a simple model? Could it simply be a constant times deltaT for the first equation instead of QdelT if only temperature is the focus at first? This is not meant to be predictive.&lt;/p&gt;&#xA;" OwnerUserId="30438" LastActivityDate="2024-03-17T00:43:10.593" Title="Examining thermohaline circulation first with just temperature differences" Tags="|oceanography|ocean-currents|ocean-models|thermohaline-circulation|northatlantic|" AnswerCount="0" CommentCount="4" ContentLicense="CC BY-SA 4.0" />
  <row Id="26081" PostTypeId="1" CreationDate="2024-03-17T14:36:41.313" Score="3" ViewCount="23" Body="&lt;p&gt;When traveling through the northern parts of Chile (La Serena, Antofagasta) during November and December, I noticed a thin layer of coastal fog very close to the coastline.&lt;/p&gt;&#xA;&lt;p&gt;Since this fog was present for several weeks, I assume it to be not a short-term weather phenomenon - but why does it arise then?&lt;br /&gt;&#xA;Is it the same phenomenon as in San Francisco, for example (i. e. cold(er) Humboldt Current meets hot continental air → air cools down → fog)?&lt;/p&gt;&#xA;" OwnerUserId="31641" LastActivityDate="2024-03-17T14:36:41.313" Title="How does coastal fog form on the Chilean coast?" Tags="|meteorology|climate|clouds|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26082" PostTypeId="1" CreationDate="2024-03-18T12:12:23.210" Score="0" ViewCount="20" Body="&lt;p&gt;It dehydrates rapidly (hours) to mbobomkulite. So how would I be able to store it?&lt;/p&gt;&#xA;" OwnerUserId="30397" LastActivityDate="2024-03-18T12:12:23.210" Title="How would I be able to store Hydrombobomkulite?" Tags="|mineralogy|minerals|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26083" PostTypeId="1" CreationDate="2024-03-18T15:01:46.280" Score="2" ViewCount="21" Body="&lt;p&gt;There is a well known solution to Navier-Stokes equations for atmospheric boundary layer according to Ekman (see for instance PalArya's book &amp;quot;Introduction to Micrometeorology&amp;quot; or Holton's &amp;quot;Introduction to dynamic Meteorology&amp;quot;):&#xA;&lt;a href=&quot;https://i.stack.imgur.com/UD5ta.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/UD5ta.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;span class=&quot;math-container&quot;&gt;$u_g$&lt;/span&gt; is the geostrophic wind (assumed in x direction), u, v denote the real wind components , &lt;span class=&quot;math-container&quot;&gt;$\gamma=\sqrt{f/2\nu}$&lt;/span&gt;, f=Coriolis parameter, &lt;span class=&quot;math-container&quot;&gt;$\nu$&lt;/span&gt; denotes viscosity.&lt;/p&gt;&#xA;&lt;p&gt;By plotting this z-behavior of u and v I made the observation, that frictional force is in general &lt;strong&gt;not antiparallel&lt;/strong&gt; to the wind. Taking the extreme z=0, wind is even zero and there must be a balance of frictional force with Coriolis force. In the following graph the vectors of real wind &lt;span class=&quot;math-container&quot;&gt;$\vec v$&lt;/span&gt; (green), geostrophic wind &lt;span class=&quot;math-container&quot;&gt;$\vec v_g$&lt;/span&gt; (red) and ageostrophic wind &lt;span class=&quot;math-container&quot;&gt;$\vec v_a$&lt;/span&gt; (yellow) are drawn together with the forces for total Coriolis (dotted green), negative pressure gradient force (dotted red) and frictional force (dotted yellow).&lt;/p&gt;&#xA;&lt;p&gt;I'm surprised that in this solution the frictional force (as calculated from second derivatives of u and v with regard to z) is not parallel to the overall wind, even though it is the case in many meteorology books and online material, e.g. B. &lt;a href=&quot;https://apollo.nvu.vsc.edu/classes/met130/notes/chapter8/fr_aloft_gr.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;here&lt;/a&gt;. Why is there such a “discrepancy” between the Ekman solution above and what we find elsewhere?&lt;/p&gt;&#xA;&lt;p&gt;I find it a bit counterintuitive that friction is not aligned with the wind direction. Could it be that I have a misunderstanding?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/Pa4a5.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/Pa4a5.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="21047" LastEditorUserId="21047" LastEditDate="2024-03-20T06:59:41.887" LastActivityDate="2024-03-20T06:59:41.887" Title="Can frictional force be un-aligned with wind direction?" Tags="|meteorology|wind|atmosphere-modelling|planetary-boundary-layer|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26084" PostTypeId="1" CreationDate="2024-03-18T22:24:24.920" Score="4" ViewCount="59" Body="&lt;p&gt;Earth Science community,&lt;/p&gt;&#xA;&lt;p&gt;I've encountered a puzzling issue with a dataset from NOAA's Local Climatological Data Airports Database (which can be accessed here: &lt;a href=&quot;https://www.ncei.noaa.gov/data/local-climatological-data/access&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.ncei.noaa.gov/data/local-climatological-data/access&lt;/a&gt;). After converting the precipitation data from inches per hour to millimeters per hour, I noticed an abrupt and sustained increase in the mean values, (i.e mean monthly or monthly totals) starting in 2001 across all stations in the dataset.&lt;/p&gt;&#xA;&lt;p&gt;The transformation applied was a straightforward conversion (1 inch = 25.4 millimeters), but the resultant values post-2001 seem abnormally high when compared to previous years. This is noticeable when plotting the data, which shows a significant jump in the mean precipitation amounts that don't align with historical trends.&lt;/p&gt;&#xA;&lt;p&gt;The jump persists even without the conversion.&#xA;This is clearly an artifact and not related to precipitation trends. The monthly values after 2001 are too high for mean monthly precipitation in New England Region.&lt;/p&gt;&#xA;&lt;p&gt;Have there been any known changes in measurement techniques, data recording, or other methodological shifts at NOAA stations during this period that might explain this anomaly? Is it possible that a reporting change could have affected the data collection?&lt;/p&gt;&#xA;&lt;p&gt;Any insights or tips on why there could be such a discrepancy or where to look further would be greatly appreciated. I am using the Airports Database since it has other variables in addition to precipitation that are relevant to my analysis.&lt;/p&gt;&#xA;&lt;p&gt;Thank you for your assistance&lt;img src=&quot;https://i.stack.imgur.com/XcVf9.png&quot; alt=&quot;Trends: See the difference before and after 2001&quot; /&gt;&lt;/p&gt;&#xA;" OwnerUserId="30006" LastEditorUserId="30006" LastEditDate="2024-03-18T22:43:58.923" LastActivityDate="2024-03-27T04:19:59.393" Title="Unexplained Jump in NOAA Climatological Data Post-2001" Tags="|climate|temperature|precipitation|statistics|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="26085" PostTypeId="1" CreationDate="2024-03-19T00:13:35.987" Score="7" ViewCount="80" Body="&lt;p&gt;A picture is better than a long explanation. The boat is long gone but its wake is visible for a very long time and forms a pattern looking like a trail on the sea surface. The two lines are not even divergent like the envelope of the wake. My first guess is that it is created by a change in refractive index of the water due to a non uniform mixing of the water temperature in the rear of the boat. But I can't explain why the perturbation is stable. It should diffuse or be conic as the wake of the boat.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/2Lt4D.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/2Lt4D.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/PrOXi.png&quot; rel=&quot;noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/PrOXi.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="31649" LastActivityDate="2024-04-02T21:13:20.380" Title="Why does the wake of boats leave a long lasting print on the sea surface?" Tags="|oceanography|ocean-currents|ocean-models|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="26086" PostTypeId="2" ParentId="26075" CreationDate="2024-03-19T11:06:01.667" Score="1" Body="&lt;p&gt;Yes, check the &lt;a href=&quot;https://nsidc.org/data/nsidc-0780/versions/1&quot; rel=&quot;nofollow noreferrer&quot;&gt;Arctic and Antarctic Regional Masks for Sea Ice and Related Data Products&lt;/a&gt;. You will need to create an account to be able to download files (masks), for example in NetCDF format, with spatial definitions of Arctic regional seas. Files are available in multiple resolutions.&lt;/p&gt;&#xA;&lt;p&gt;Here is a short part of their metadata describing several (sea-ice) regions:&lt;/p&gt;&#xA;&lt;pre&gt;&lt;code&gt;netcdf NSIDC-0780_SeaIceRegions_PS-N25km_v1.0 {&#xA;dimensions:&#xA;    y = 448 ;&#xA;    x = 304 ;&#xA;variables:&#xA;    ubyte sea_ice_region(y, x) ;&#xA;        sea_ice_region:_FillValue = 255UB ;&#xA;        sea_ice_region:standard_name = &amp;quot;region&amp;quot; ;&#xA;        sea_ice_region:long_name = &amp;quot;sea ice region mask&amp;quot; ;&#xA;        sea_ice_region:grid_mapping = &amp;quot;crs&amp;quot; ;&#xA;        sea_ice_region:valid_range = 0UB, 18UB ;&#xA;        sea_ice_region:_Unsigned = &amp;quot;true&amp;quot; ;&#xA;        sea_ice_region:flag_values = 0UB, 1UB, 2UB, 3UB, 4UB, 5UB, 6UB, 7UB, 8UB, 9UB, 10UB, 11UB, 12UB, 13UB, 14UB, 15UB, 16UB, 17UB, 18UB ;&#xA;        sea_ice_region:flag_meanings = &amp;quot;ocean_no_region_specified central_arctic beaufort_sea chukchi_sea east_siberian_sea laptev_sea kara_sea barents_sea east_greenland_sea baffin_bay_and_labrador_seas gulf_of_st_lawrence hudson_bay canadian_archipelago bering_sea sea_of_okhotsk sea_of_japan bohai_and_yellow_seas baltic_sea gulf_of_alaska&amp;quot; ;&#xA;&lt;/code&gt;&lt;/pre&gt;&#xA;" OwnerUserId="8396" LastActivityDate="2024-03-19T11:06:01.667" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="26087" PostTypeId="1" CreationDate="2024-03-19T11:21:16.690" Score="1" ViewCount="56" Body="&lt;p&gt;Do tropical cyclones (TCs) have a global impact on climate? Maybe in terms of their impact on air-sea heat or gas fluxes? For example cooling the surface ocean, or enhancing CO2 fluxes?&lt;/p&gt;&#xA;&lt;p&gt;The motivation behind this question is that CMIP6-type Earth system models (ESMs) are often too coarse in resolution to represent TCs. If climate were represented with a high-resolution model, which can reproduce TCs and their air-sea interactions, what aspect of the global climate would potentially be better represented? Would this improvement be relevant at the global scale? Would this be a good reason to push ESMs towards high resolution?&lt;/p&gt;&#xA;" OwnerUserId="8396" LastActivityDate="2024-03-31T10:57:38.067" Title="Do tropical cyclones impact climate?" Tags="|meteorology|oceanography|climate-models|tropical-cyclone|" AnswerCount="1" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="26089" PostTypeId="1" AcceptedAnswerId="26119" CreationDate="2024-03-20T20:56:56.757" Score="5" ViewCount="77" Body="&lt;p&gt;The coldest temperature ever measured at &lt;a href=&quot;https://en.wikipedia.org/wiki/Vostok_Station&quot; rel=&quot;noreferrer&quot;&gt;Vostok Station&lt;/a&gt; is -89.2 °C, well below the sea-level sublimation point of carbon dioxide at -78.5 °C.  However, Vostok Station is well above sea level (3488 m).  Is this still cold enough to get natural dry ice, or is there some other location with a combination of temperature and altitude that can form dry ice?  (&lt;a href=&quot;https://en.wikipedia.org/wiki/Plateau_Station&quot; rel=&quot;noreferrer&quot;&gt;Plateau Station&lt;/a&gt;, for example, is slightly higher and is suspected to be even colder.)&lt;/p&gt;&#xA;" OwnerUserId="2643" LastActivityDate="2024-04-01T19:55:33.570" Title="Does carbon dioxide naturally freeze on Earth?" Tags="|climate|" AnswerCount="1" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="26090" PostTypeId="1" CreationDate="2024-03-20T21:45:44.097" Score="0" ViewCount="22" Body="&lt;p&gt;Is there a rough empirical formula that approximates local average annual air temperature and pressure from geographical latitude, altitude and distance from ocean shore?&lt;/p&gt;&#xA;" OwnerUserId="31658" LastActivityDate="2024-03-20T21:45:44.097" Title="Rough empirical formula for average temperature and pressure" Tags="|climate|temperature|models|climate-models|barometric-pressure|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="26091" PostTypeId="2" ParentId="2241" CreationDate="2024-03-20T23:43:27.273" Score="1" Body="&lt;p&gt;there actually is a continuum of size , examples include mesovorticesa and remnant lows&lt;/p&gt;&#xA;" OwnerUserId="30498" LastActivityDate="2024-03-20T23:43:27.273" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="26092" PostTypeId="2" ParentId="22476" CreationDate="2024-03-21T01:03:11.593" Score="1" Body="&lt;p&gt;The energy for the the evaporation of cloud droplet generally comes from the thermal energy present in the droplets themselves&#xA;The reason some clouds dissipate only partially is several-fold&lt;br /&gt;&#xA;1: the thermal energy becomes depleted and is insufficient to produce further evaporation.&lt;br /&gt;&#xA;2: the cooler water droplet absorbs heat from the air, causing it to contract which changes the air flow.&lt;br /&gt;&#xA;3: the amount of water Vapor in the air increases to a point where water is replaced from water Vapor at a speed that balances out evaporation.&lt;/p&gt;&#xA;" OwnerUserId="30498" LastActivityDate="2024-03-21T01:03:11.593" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26093" PostTypeId="5" CreationDate="2024-03-21T07:06:41.713" Score="0" Body="" OwnerUserId="-1" LastEditorUserId="-1" LastEditDate="2024-03-21T07:06:41.713" LastActivityDate="2024-03-21T07:06:41.713" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26094" PostTypeId="4" CreationDate="2024-03-21T07:06:41.713" Score="0" Body="A tornado is a rapidly rotating column of air connected to a cumulus or cumulonimbus cloud as well as the ground" OwnerUserId="30498" LastEditorUserId="30498" LastEditDate="2024-03-27T21:47:40.903" LastActivityDate="2024-03-27T21:47:40.903" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26095" PostTypeId="1" CreationDate="2024-03-21T13:43:45.813" Score="1" ViewCount="39" Body="&lt;p&gt;I keep reading that global air temperature has been recorded since 1880, but considering that it wasn't until 1911 that Amundsen became the first person to reach the South Pole, it cannot be assumed that air temperature was globally recorded. Since when have regular air temperature data been available from, for example, the two polar regions?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2024-03-21T13:43:45.813" Title="Since when are there global air temperature measurements?" Tags="|climate-change|temperature|weather-satellites|" AnswerCount="0" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="26096" PostTypeId="1" CreationDate="2024-03-21T20:09:39.050" Score="2" ViewCount="79" Body="&lt;p&gt;I am curious about how various estimates can divert. The first picture is taken from a recent publication of VisualCapitalist&#xA;&lt;a href=&quot;https://www.visualcapitalist.com/sp/hf01-visualizing-all-of-the-worlds-water/&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.visualcapitalist.com/sp/hf01-visualizing-all-of-the-worlds-water/&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;The second picture can be found in an older Soviet book by Larionov published in 1989, the book's called &amp;quot;Amusing hydrogeology&amp;quot;.&lt;/p&gt;&#xA;&lt;p&gt;As can be seen, the estimates of the groundwater are rather different. The Russian book puts its estimate at roughly the same level with oceans, while Visual Capitalist estimated it at the same level with glaciers.&lt;/p&gt;&#xA;&lt;p&gt;So the question remains, what estimate is more valid?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/fCzRf.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/fCzRf.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/XAfnN.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/XAfnN.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="30167" LastActivityDate="2024-03-25T09:32:15.440" Title="How much water does the Earth contain?" Tags="|water|groundwater|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="26097" PostTypeId="1" CreationDate="2024-03-22T10:40:31.147" Score="1" ViewCount="41" Body="&lt;p&gt;I evaluate the performance of the model through the computation of statistical parameter such as bias, R, IOA and other. (i compare it with in situ measurements)&#xA;However, wind direction (range 0 to 360 in degrees) has difficult characteristics. Thus, I would like to ask if you know statistics tailored to wind direction.&lt;/p&gt;&#xA;&lt;p&gt;Thanks&lt;/p&gt;&#xA;" OwnerUserId="30273" LastActivityDate="2024-03-22T10:40:31.147" Title="Wind direction statistics" Tags="|wind|statistics|" AnswerCount="0" CommentCount="5" ContentLicense="CC BY-SA 4.0" />
  <row Id="26098" PostTypeId="2" ParentId="26096" CreationDate="2024-03-22T11:12:20.470" Score="4" Body="&lt;p&gt;The accompanying text to the second image states &lt;em&gt;&amp;quot;The second place is occupied by the mass of invisible water in the earth's crust and partly in the mantle. Here it contains about 1300 million km³.&amp;quot;&lt;/em&gt; The key statement is that the estimate includes water in the mantle, as well as the crust. The smaller figure, of 23 million km³, quoted in the first image, is an estimate of groundwater that might be considered to be in active circulation, albeit in some cases at millennial timescales.  Estimates of groundwater volume can vary considerably, depending on assumptions about depth, movement and porosity etc. Groundwater volume is often quoted as high as 60 million km³, twice the volume of glaciers. The amount that might be actually accessible to ecosystems or abstraction is likely to be at least an order of magnitude lower, maybe as low as or as low as 4 million km³.&lt;/p&gt;&#xA;" OwnerUserId="21672" LastEditorUserId="21672" LastEditDate="2024-03-25T09:32:15.440" LastActivityDate="2024-03-25T09:32:15.440" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26099" PostTypeId="2" ParentId="26067" CreationDate="2024-03-22T14:17:03.660" Score="2" Body="&lt;blockquote&gt;&#xA;&lt;p&gt;What do they mean by that? Did they mean that since 1900 when they recorded El Nino, the 2023-24 El Niño season was the fifth strongest on record recorded by World Meteorological Organization?&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;While the World Meteorological Organization did not qualify what they meant by &amp;quot;fifth strongest&amp;quot;, apparently they meant since 1950, which is when reliable temperature readings of sea surface temperatures in what is now called the Niño 3.4 region began. The Southern Oscillation Index (SOI), the pressure difference between Tahiti and Darwin Australia, goes back to 1900. The SOI and Oceanic Niño Index (ONI) based on the Niño 3.4 region are strongly but not perfectly correlated (actually, anti-correlated; when the SOI is high the ONI tends to be low, and the other way around). The ONI is now widely used as the measure of whether an El Niño or La Niña is occurring (or about to occur). Here's a chart of strong El Niños since 1950:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/ynWKq.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/ynWKq.png&quot; alt=&quot;Monthly sea surface temperature Niño 3.4 Index values, showing every strong El Niño since 1950&quot; /&gt;&lt;/a&gt;&lt;br /&gt;&#xA;&lt;sup&gt;Source: &lt;a href=&quot;https://www.climate.gov/media/15936&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://www.climate.gov/media/15936&lt;/a&gt;&lt;/sup&gt;&lt;/p&gt;&#xA;&lt;p&gt;The ENSO blog team at climate.gov wrote &lt;a href=&quot;https://www.climate.gov/news-features/blogs/enso/december-2023-el-nino-update-adventure&quot; rel=&quot;nofollow noreferrer&quot;&gt;this back in December 2023&lt;/a&gt;:&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;We use a three-month average because ENSO is a seasonal phenomenon, meaning it persists for at least several months. We don’t have official strength definitions, but, unofficially, an ONI anomaly of 1.5 °C or warmer is considered a strong El Niño, with 2.0 °C the threshold for “very strong” or “historically strong.”&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;This was before the current El Niño peaked at just about 2.0 °C, so just at the threshold of &amp;quot;historically strong.&amp;quot; From the graph, there are four other El Niños that were clearly stronger than the current one, and one other that also peaked at just about 2.0 °C. However, that other one (1965-1966) peaked a bit early. Using the November to January average, which is widely used as the bellwether indicator of the strength of an El Niño, the current one ranks as the fifth strongest since 1950. However, if one instead uses an &amp;quot;all-winter&amp;quot; point of view, the current one is &amp;quot;only&amp;quot; tied for fifth -- and that's only since 1950.&lt;/p&gt;&#xA;" OwnerUserId="239" LastActivityDate="2024-03-22T14:17:03.660" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26100" PostTypeId="1" CreationDate="2024-03-23T15:46:27.817" Score="-1" ViewCount="21" Body="&lt;p&gt;Earth magnetic field is produced by the convection currents of Ni and Fe in the outer core, but why should the movement of Fe and Ni produce a magnetic field? Fe and Ni form a metallic compound, made of ions as well as electrons, thus it should be neutral and should not cause any electric currents while moving.&lt;/p&gt;&#xA;" OwnerUserId="31666" LastActivityDate="2024-03-23T15:46:27.817" Title="Why does Ni and Fe alloy that forms the outer core produce earth magnetic field?" Tags="|geomagnetism|core|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="26101" PostTypeId="1" CreationDate="2024-03-23T16:31:57.190" Score="3" ViewCount="75" Body="&lt;p&gt;Since the first rocks of the pacific Ocean plates solidified from magma coming out of a rift 750 million years ago, shouldn't they be much older than the maximum age of oceanic crust (around 200 million years)?&lt;/p&gt;&#xA;" OwnerUserId="31666" LastActivityDate="2024-04-03T10:56:58.147" Title="If the Pacific Ocean is 750 million years old, Why can't oceanic crust be older than 200 million years?" Tags="|plate-tectonics|oceanic-crust|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="26102" PostTypeId="1" CreationDate="2024-03-24T11:05:29.173" Score="1" ViewCount="51" Body="&lt;p&gt;I was casually browsing the google earth street view map today. And I noticed strange cavities in a rock wall on Henderson Island, a coral island in the South Pacific. What could have caused this to form?&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://earth.app.goo.gl/?apn=com.google.earth&amp;amp;isi=293622097&amp;amp;ius=googleearth&amp;amp;link=https%3A%2F%2Fearth.google.com%2Fweb%2F%40-24.34041526,-128.3284743,28.870924a,0d,90y,119.85663851h,103.66404756t,0r%2Fdata%3DIhoKFlJJMzBsVUVOSnFraUpOS2xsUmUzVmcQAjoDCgEw&quot; rel=&quot;nofollow noreferrer&quot;&gt;link&lt;/a&gt;&#xA;&lt;a href=&quot;https://i.stack.imgur.com/oUG3O.jpg&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/oUG3O.jpg&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="30280" LastActivityDate="2024-03-24T11:15:56.687" Title="How do these holes form?" Tags="|geology|rocks|islands|pacific|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="26103" PostTypeId="2" ParentId="26102" CreationDate="2024-03-24T11:15:56.687" Score="0" Body="&lt;p&gt;These are calcite-based rock layers and the reaction between these and H2CO3 (CO2 +H2O) causes the calcite to erode.&lt;/p&gt;&#xA;&lt;p&gt;Consequently, the reaction:&lt;/p&gt;&#xA;&lt;p&gt;H2O +CO2 -&amp;gt; H2CO3&lt;/p&gt;&#xA;&lt;p&gt;H2CO3 +CaCO3 &amp;lt;-&amp;gt; Ca + 2 HCO3&lt;/p&gt;&#xA;&lt;p&gt;This reactin is mainly found in slightly acidic environments.&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2024-03-24T11:15:56.687" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26104" PostTypeId="1" CreationDate="2024-03-25T11:31:15.567" Score="1" ViewCount="40" Body="&lt;p&gt;The Arctic has lost 3.6 million km^2 of sea ice due to climate change. This is also referred to as freshening. Are there any studies focussing on the development of the salinity of the North Atlantic?&lt;/p&gt;&#xA;" OwnerUserId="26841" LastActivityDate="2024-03-25T11:31:15.567" Title="How the salinity of the North Atlantic is changing" Tags="|climate-change|arctic|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="26105" PostTypeId="2" ParentId="26101" CreationDate="2024-03-26T09:50:34.107" Score="6" Body="&lt;p&gt;Expanding on @Jean-Marie Prival's comment:&lt;/p&gt;&#xA;&lt;p&gt;Basically, on geological timescales the ocean has a convener belt of &lt;a href=&quot;https://en.wikipedia.org/wiki/Oceanic_crust&quot; rel=&quot;nofollow noreferrer&quot;&gt;oceanic crust&lt;/a&gt; underneath it, where new crust forms and old crust is destroyed. This means the ocean can be much older than the age of crust underneath it.&lt;/p&gt;&#xA;&lt;p&gt;Oceanic plates are driven by convection currents in the mantle which is formed of molten rock, with the top-most part of the mantle (the &lt;a href=&quot;https://en.wikipedia.org/wiki/Asthenosphere&quot; rel=&quot;nofollow noreferrer&quot;&gt;asthenosphere&lt;/a&gt;) only being partially melted.&lt;/p&gt;&#xA;&lt;p&gt;These convection currents create areas up uplift where magma (molten rock) pushes through to the crust and solidifies forming a &lt;a href=&quot;https://en.wikipedia.org/wiki/Mid-ocean_ridge&quot; rel=&quot;nofollow noreferrer&quot;&gt;mid-oceanic ridge&lt;/a&gt; and so new oceanic crust.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/7u5QO.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/7u5QO.png&quot; alt=&quot;Simplified schematic of convection currents in the mantle driving plate tectonics with areas of uplift where new oceanic crust is formed and areas of subduction where it is melted.&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;&lt;em&gt;Credit &lt;a href=&quot;https://commons.wikimedia.org/wiki/File:Oceanic_spreading.svg&quot; rel=&quot;nofollow noreferrer&quot;&gt;Wikimedia User:Surachit&lt;/a&gt; Licence: &lt;a href=&quot;https://creativecommons.org/licenses/by-sa/3.0/deed.en&quot; rel=&quot;nofollow noreferrer&quot;&gt;CC BY-SA 3.0 DEED&lt;/a&gt;&lt;/em&gt;&lt;/p&gt;&#xA;&lt;p&gt;This crust is moved along by the convection currents. The ridge is there because of the upwards pressure of the convection current. When the rock moves away this upwards pressure is no longer present so the surface lowers. Eventually the crust reaches a &lt;a href=&quot;https://en.wikipedia.org/wiki/Subduction&quot; rel=&quot;nofollow noreferrer&quot;&gt;subduction zone&lt;/a&gt; and is reabsorbed by the mantle. If you traced some freshly-made rock you can find that the solid-rock's lifetime can be significantly shorter than the ocean's lifetime above it.&lt;/p&gt;&#xA;&lt;p&gt;Subduction zones exist, because oceanic crust, which is mainly made up of low-silica &lt;a href=&quot;https://en.wikipedia.org/wiki/Basalt&quot; rel=&quot;nofollow noreferrer&quot;&gt;basalts&lt;/a&gt;, is denser than &lt;a href=&quot;https://en.wikipedia.org/wiki/Continental_crust&quot; rel=&quot;nofollow noreferrer&quot;&gt;continental crust&lt;/a&gt;, which is mainly made up of high-silica &lt;a href=&quot;https://en.wikipedia.org/wiki/Granite&quot; rel=&quot;nofollow noreferrer&quot;&gt;granites&lt;/a&gt;. This means, when the two meet, the denser oceanic crust goes underneath and the less-dense continental crust floats on top. The weight of the continental crust, pushes the oceanic crust further down where there is more heat so it begins to melt.&lt;/p&gt;&#xA;&lt;p&gt;As an aside, the earth's magnetic field flips periodically. The &lt;a href=&quot;https://flexbooks.ck12.org/cbook/ck-12-middle-school-earth-science-flexbook-2.0/section/5.5/primary/lesson/magnetic-evidence-for-seafloor-spreading-ms-es/&quot; rel=&quot;nofollow noreferrer&quot;&gt;polarity of the magnetic field is recorded in the rocks&lt;/a&gt; as they solidify. This means this polarity signal forms a mirror image on either side of the mid-oceanic ridge. This is one of the initial pieces of information that was used to show that oceanic plates move and also one of the ways the speed of the movement was calculated.&lt;/p&gt;&#xA;" OwnerUserId="20542" LastEditorUserId="20542" LastEditDate="2024-04-03T10:56:58.147" LastActivityDate="2024-04-03T10:56:58.147" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26106" PostTypeId="2" ParentId="26050" CreationDate="2024-03-27T02:28:39.323" Score="2" Body="&lt;p&gt;There may be potential in &lt;a href=&quot;https://agupubs.onlinelibrary.wiley.com/doi/10.1029/2023EF003698&quot; rel=&quot;nofollow noreferrer&quot;&gt;carbon capture&lt;/a&gt; using the &lt;a href=&quot;https://en.wikipedia.org/wiki/Carbonate%E2%80%93silicate_cycle&quot; rel=&quot;nofollow noreferrer&quot;&gt;carbon silicate cycle&lt;/a&gt; to our advantage. The carbon silicate cycle occurs on geologic timescales, but &amp;quot;enhanced rock weathering&amp;quot; seeks to speed up the process by finely grinding basalt or silicates, giving them greater surface area and greater exposure to air.&lt;/p&gt;&#xA;&lt;p&gt;Scientists in the first article found using their model that&lt;/p&gt;&#xA;&lt;blockquote&gt;&#xA;&lt;p&gt;Applying a fixed rate of 10 tons of basalt dust per hectare on these sites sequesters 64 gigatons of CO2 over a 75-year period; when extrapolated to all agricultural land, ERW sequesters 217 gigatons of CO2 over the same time interval.&lt;/p&gt;&#xA;&lt;/blockquote&gt;&#xA;&lt;p&gt;217 gigatons of CO2 is not trivial, although distributing 10 tons of basalt per hectare over all agricultural land is also not trivial. There is discussion on its viability because of cost of implementation, and the fossil fuels that will be used to mine the basalt or whatever type of substrate, and then distribute it.&lt;/p&gt;&#xA;&lt;p&gt;edit: I feel compelled to add that of course, this is not a remotely viable solution itself. The only solution is a push towards complete decarbonization immediately.&lt;/p&gt;&#xA;" OwnerUserId="31679" LastEditorUserId="31679" LastEditDate="2024-03-27T02:35:18.170" LastActivityDate="2024-03-27T02:35:18.170" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26107" PostTypeId="2" ParentId="26084" CreationDate="2024-03-27T04:19:59.393" Score="1" Body="&lt;p&gt;I'm using a &lt;a href=&quot;https://scacis.rcc-acis.org/&quot; rel=&quot;nofollow noreferrer&quot;&gt;quick NOAA tool&lt;/a&gt; to check precipitation values and I don't see any kind of jump in 2001.&lt;/p&gt;&#xA;&lt;p&gt;I'm looking at &amp;quot;single station products&amp;quot;, Boston Logan Airport, and precipitation (sum) from 1999-2005 to see monthly total precipitation. Then, averaging those monthly totals.&lt;/p&gt;&#xA;&lt;p&gt;In 2001, I'm getting 2.56  (65 mm) inches precipitation per month, and your plot is saying closer to 100mm. I'm not sure where this discrepancy is coming from but you may want to check what you're averaging. I think your problems do not just start after 2001, but are high throughout your plots.&lt;/p&gt;&#xA;" OwnerUserId="31679" LastActivityDate="2024-03-27T04:19:59.393" CommentCount="2" ContentLicense="CC BY-SA 4.0" />
  <row Id="26108" PostTypeId="1" CreationDate="2024-03-27T12:03:26.840" Score="2" ViewCount="28" Body="&lt;p&gt;I understand that wrf.getvar will give both the speed (dim 0) and the direction (dim 1)&#xA;V1 = wrf.getvar(ncdin, &amp;quot;uvmet10_wspd_wdir&amp;quot;, units=&amp;quot;m s-1&amp;quot;,timeidx=wrf.ALL_TIMES,meta=False)[1,...]&lt;/p&gt;&#xA;&lt;p&gt;But, I would like to ask about the way that direction is provided by the package. 0 degrees is wind from the north, 90 from the east etc?&#xA;For example if the output for dim 1 is 45 the wind is northestearn?&lt;/p&gt;&#xA;&lt;p&gt;P.S. The link (&lt;a href=&quot;https://wrf-python.readthedocs.io/en/latest/internal_api/generated/wrf.g_uvmet.get_uvmet10_wspd_wdir.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;https://wrf-python.readthedocs.io/en/latest/internal_api/generated/wrf.g_uvmet.get_uvmet10_wspd_wdir.html&lt;/a&gt;) may be useful.&lt;/p&gt;&#xA;&lt;p&gt;Thanks,&#xA;Dimitris&lt;/p&gt;&#xA;" OwnerUserId="30273" LastEditorUserId="30273" LastEditDate="2024-03-28T08:25:15.600" LastActivityDate="2024-03-28T08:25:15.600" Title="Providing wind direction with wrf-python package" Tags="|wind|python|wrf|" AnswerCount="0" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26110" PostTypeId="1" CreationDate="2024-03-28T22:59:21.213" Score="0" ViewCount="33" Body="&lt;p&gt;I have a question regarding zoeppritz equations. The equations from Telford are as follwoing:&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/WHyRp.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/WHyRp.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;&lt;p&gt;When trying to put in a matrix form, by converting amplitudes to reflection and transmission coefficients, doing so, by dividing by 'A0'&lt;/p&gt;&#xA;&lt;p&gt;Comparing my results and the standard matrix form of Zoeppritz equation, I found that the last column in the &amp;quot;A&amp;quot; matrix has an opposed sign. What am I missing ? How can i convert these set of equations to the matrix form.&lt;/p&gt;&#xA;&lt;p&gt;&lt;a href=&quot;https://i.stack.imgur.com/G6KhS.png&quot; rel=&quot;nofollow noreferrer&quot;&gt;&lt;img src=&quot;https://i.stack.imgur.com/G6KhS.png&quot; alt=&quot;enter image description here&quot; /&gt;&lt;/a&gt;&lt;/p&gt;&#xA;" OwnerUserId="31690" LastEditorUserId="31690" LastEditDate="2024-03-30T18:43:00.953" LastActivityDate="2024-03-30T18:43:00.953" Title="Zoeppritz equations" Tags="|seismology|seismic|" AnswerCount="0" CommentCount="3" ContentLicense="CC BY-SA 4.0" />
  <row Id="26111" PostTypeId="1" CreationDate="2024-03-29T07:37:28.440" Score="2" ViewCount="33" Body="&lt;p&gt;How is information concerning the height of a tsunami obtained?&#xA;Does not the incoming and out going wave scour the area of natural and man made structures, hindering an accurate measurement?&lt;/p&gt;&#xA;" OwnerUserId="31694" LastActivityDate="2024-03-29T07:37:28.440" Title="How do scientists determine the height measurement of a tsunami wave after the event?" Tags="|tsunami|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="26112" PostTypeId="1" CreationDate="2024-03-29T16:02:30.483" Score="1" ViewCount="8" Body="&lt;p&gt;any ideas how to convert Rcd and Dst seismic data into SEGY?&lt;/p&gt;&#xA;" OwnerUserId="31696" LastActivityDate="2024-03-29T16:02:30.483" Title="hi, any ideas how to convert Rcd and Dst seismic data into SEGY?" Tags="|geology|geophysics|seismic|" AnswerCount="0" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="26113" PostTypeId="1" CreationDate="2024-03-31T03:13:48.640" Score="0" ViewCount="58" Body="&lt;p&gt;They say humans would need to mine 1% of moons mass to have an effect on earth's gravitational pull.&lt;/p&gt;&#xA;&lt;p&gt;Since the moon is 1.2% of the size of earth (tiny) &amp;amp; the minerals mined on the moon will be removed from the moon, is it in the realm of possibility that humans could achieve that 1% mass reduction, via mining?&lt;/p&gt;&#xA;&lt;p&gt;Humans have mined a fair amount on earth - but most of it stays on earth&lt;/p&gt;&#xA;&lt;p&gt;There's no direct answer from -Google search -on how much of earth's mass has been mined, I'm unable to do calculations in comparison to moon's mass, hense asking this question on your website&lt;/p&gt;&#xA;" OwnerUserId="31701" LastEditorUserId="31701" LastEditDate="2024-03-31T03:16:26.260" LastActivityDate="2024-03-31T19:51:39.663" Title="Have we mined more on earth than 1% mass of moon? Because doing that to moon could potentially effect its gravitational pull" Tags="|tides|mining|earth-moon|" AnswerCount="1" CommentCount="1" ContentLicense="CC BY-SA 4.0" />
  <row Id="26114" PostTypeId="2" ParentId="26113" CreationDate="2024-03-31T10:09:26.130" Score="2" Body="&lt;p&gt;The &lt;a href=&quot;https://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html&quot; rel=&quot;nofollow noreferrer&quot;&gt;mass of the Moon&lt;/a&gt; is 0.07346 × 10&lt;sup&gt;24&lt;/sup&gt; kg (or 7.346 × 10&lt;sup&gt;22&lt;/sup&gt; kg). One percent of that is 7.346 × 10&lt;sup&gt;20&lt;/sup&gt; kg, or 7.346 × 10&lt;sup&gt;19&lt;/sup&gt; tonnes.&lt;/p&gt;&#xA;&lt;p&gt;If you consider &lt;a href=&quot;https://www.statista.com/statistics/267380/iron-ore-mine-production-by-country/&quot; rel=&quot;nofollow noreferrer&quot;&gt;iron ore&lt;/a&gt; alone, global production in 2023 was 2.544 billion tonnes (2.544 × 10 &lt;sup&gt;9&lt;/sup&gt;).&lt;/p&gt;&#xA;&lt;p&gt;Global &lt;a href=&quot;https://www.iea.org/data-and-statistics/charts/global-coal-production-2018-2021&quot; rel=&quot;nofollow noreferrer&quot;&gt;production of coal&lt;/a&gt; in 2021 was 7.574 billion tonnes. Combined with iron the total is in excess of 10 billion tonnes. These two items are the two that are mined in such quantities globally. In 2020 &lt;a href=&quot;https://www.world-mining-data.info/wmd/downloads/PDF/WMD2022.pdf&quot; rel=&quot;nofollow noreferrer&quot;&gt;total global production of minerals&lt;/a&gt; was just under 18 billion tonnes.&lt;/p&gt;&#xA;&lt;p&gt;Mining production only increases with time. Humans have not come close to mining one percent the mass of the Moon.&lt;/p&gt;&#xA;&lt;p&gt;The other thing to consider is that not all that is mined is useful; some of it is waste that needs to be mined to get what is wanted. This is particularly the situation with open pit mining where, depending on the commodity, orebody geometry and depth and mining parameters such as slope angle and catch bench widths and haul road widths more waste can be mined that the mineral desired. The waste material would stay on the Moon as waste or spoil dumps and the waste from processing plants would be stored in tailing dumps.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2024-03-31T10:09:26.130" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
  <row Id="26115" PostTypeId="2" ParentId="26087" CreationDate="2024-03-31T10:57:38.067" Score="0" Body="&lt;p&gt;When the overall energy of the atmosphere is considered, mainly &lt;a href=&quot;https://pressbooks-dev.oer.hawaii.edu/atmo/chapter/chapter-3-thermodynamics/&quot; rel=&quot;nofollow noreferrer&quot;&gt;thermal&lt;/a&gt; and kinetic, the energy contained by tropical cyclones is much smaller. Climate change affects the severity &amp;amp; frequency of tropical cyclones, not the other way around. The tail doesn't wag the dog.&lt;/p&gt;&#xA;" OwnerUserId="2470" LastActivityDate="2024-03-31T10:57:38.067" CommentCount="0" ContentLicense="CC BY-SA 4.0" />
</posts>